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realization of active filters using operational transconductance

1. PORT A A0 A7 PORT B B0 67 DECODER BUFFER DO D A13 A15 8255 PORT C CO C3 ADO AD DO D7 QC Q7 gt PORT C C4 C2 j DECODER AS8 A12 BUFFER 8085 BUFFER 1A1 1A4 amp 2A1 1Yi 1Y4 amp 2Y1i Fig 2 Block Diagram of Microprocessor Card 36 A K Hanjura position marker The frame is divided into ten sub frames each of 10 pulses First sub frame starts with two consecutive position markers followed by eight binary bits representing second Second sub frame starts with a position marker followed by 9 data bits representing the minute Third fourth and fifth sub frames are quite similar to the second one and represent the hour days and hundreds of days 3 SYSTEM HARDWARE 3 1 Microprocessor Card for Decoding of IRIG B Time Code The decoding of the incoming IRIG B time code is done using INTEL 8085 CPU based card The block diagram of the card designed for this purpose is shown in fig 2 It comprises the CPU 8085 a Programmable Peripheral Interface 8255 an 8k RAM 6264 an 8k EPROM 2764 various buffers and decoders All the input output lines are terminated on a 64 pin connector 3 2 Display Card The block diagram of the display card is shown in fig 3 A total of ten 7 segment displays are used to display the time and day of the year in the format HHMMSS DDD Where HR MM and SS are hour minute and second and DDD is the day of the year The data to
2. Fig 4 Input output chracteristics of wind speed sensor 3 SIGNAL CONDITIONING 3 1 Signal Conditioning for Solar Intensity Sensor The resistance of the LDR is 12KQ at near darkness The bridge is designed to have an output voltage range of 0 2 5 V Differential amplifier and clipper circuits are used to amplify the bridge output to 0 5 V and to restrict the output within 0 5 V respectively Design and implementation of remote data acquisition system for meteorology 87 Fig 5 Signal Conditioning for Solar Intensity sensor 3 2 Signal Conditioning for Wind Speed Signal The precision rectifier circuit is designed to convert the alternating voltage signal to varying DC signal A peak detector circuit is used to convert varying DC signal to constant DC signal Clipper circuits are used to restrict the output within 0 5 V 4 MICROCONTROLLER PROGRAMMING 4 1 Programming ADC 08094 The program uses 8255A programmable peripheral interface into share control signals and data signals with ADC 0809 Initially 8255 is configured in input output mode with port A as input port port B as output port port C upper as input port and port C lower as output port Port A is used for receiving analog to digital converted signal Port B is used to send channel to be selected for conversion Port C is used for control signaling ALE and SOC signals are given as a pulse through the port C lower in order to initiate the analog to digital c
3. 1 BA Ze 3 00 4 I QT 2Z k 3 Power fed to the antenna from a single source Vg in one arm m Lidge He OOM WI 2 7 k j Isolated Power in load Z in one arm P 7 I 4 where I is obtained by substituting 35a and 35b into 30b T jVz ron SS AES 00 ake 7iZ Anz Z Hk 3 Ze And P _ Zg Z Gke7 p k l 3k47 r AZ 643 BK 2 3 where Z and Z have been taken from 13 and 14 37 38 39a 39b 40a 40b 41a 41b 42a 42b 43 44 71 For k taking values 1 2 3 P P becomes 2 04 1 58 and 1 42 i e by increasing k the desired power P fed to the antenna decreases So a compromise in choosing the value of k is necessary 72 A K Agrawal 6 CONCLUSION A 4 way Power Divider cum Combiner using transmission lines has been analyzed In the analysis the lines were assumed to be a quarter wavelength long at the centre frequency of the Power Divider cum Combiner For the power divider a ratio k 1 between the powers in the coupled and isolated arms as been assumed where k is greater than unity As k is increased it was found that the coupled power increased in the power divider but decreased in the power combiner Hence a compromise value of k is required Once k is selected the characteristic impedances of the respective transmission lines can then be determined REFERENCES l R E Collin Foundations for Micro
4. H i X iJ Q Real contact TEMPERATURE TEMPERATURE AXIAL DISTANCE AXIAL DISTANCE a m Fig 1 Details of axial temperature profiles and heat flow across a joint Fig la Experimental Test Setup Development of a thermal contact conductance test facility 109 The apparatus developed to meet the above requirements is shown in Fig 1a It consists of five sub systems namely 1 Test column 2 Mechanical loading system 3 Heating circuit 4 Cooling circuit and 5 Instrumentation The system is capable of 1 operating between 0 to 250 C 2 varying the contact pressure in the range of 0 1 MPa to 40MPa 3 changing the direction of heat flow without disturbing the contact to study the directional effects 4 accommodating different sizes 10 mm to 50mm diameter of specimens in the test column 4 TEST COLUMN The test column consists of two heater cooler blocks two heat flux meters two test specimens two pairs of ball and conical seating arrangement stacked one over the other as shown in Fig 2 Fig 2 Test Column Details 1 Loading pin 2 Upper end plate 3 M S Bush 4 Tie rod 5 Heater Cooler Block 6 Heater coil 7 Teflon insulation 8 Thermocouple 9 Aluminium radiation shields 10 Copper cooling Tube 11 Heater Cooler Block 12 Ball and conical seating arrangement 13 Stack of SS 304 washers 14 Lower end plate 15 SS 304 washer H1
5. daas RIOTS J NS uu Tu E f VILLIS a a Har MGPFENVEL Tan MOLLUS HEL JanEd zEJNMgIz Jas NTI SYN To JE SRIAOTHe OMI Se 23 Aleka Es hk DH NES us vuus fn E d gue AEE AA ZH SF l E i Xi i Joes i i z RWL JE LA EL u uf YE mod aL 32 d e Arvind Kumar K K Radhakrishnan and V K Bhat from storage drum to intermediate tank is to open and the valve to close when level in TDI intermediate tank reaches the desired level Vacuum valve to close when vacuum in intermediate tank reaches to desired level and to open again when it falls below set point All these operations to takes place automatically in auto mode by just clicking the start transfer button in SCADA In manual mode these operation is to be done manually If any interlock is not fulfilling during operation then that interlock will display in SCADA 4 1 2 Intermediate tank to measuring vessel by gravity vacuum flow a b c d e f System to check the level of trap vessel amp vent seal pot If levels of both tanks are found okay then further operation to start In case of TDI transfer by vacuum start the vacuum pump and open vacuum valve of measuring vessel provided the level of measuring vessel is not high In case of gravity transfer vacuum pump and valve will not operate and vent valve of measuring vessel will open Vent valve of intermediate tank
6. e Pre liming separations and mixing Pre liming below neutral and part of juice is heated and remaining part limed upto 9 3 pH and mixing for clarity e Compound clarification the dear juice pH is about 6 8 to 7 1 Sulphitation Procedures e Cold sulphitation Sulphitation liming heating process The clear juice pH is about 6 9 to 7 0 e Hotsulphitation Heating liming sulphitation reheating settling process Sulphitation upto pH of 7 2 e Fractional liming and sulphitation Heating pre liming sulphitation final liming reheating process The final liming to pH of 7 4 In some sugar industries liming before sulphitation is carried out while in others sulphitation before liming is done 1 2 pH control Manual or Automatic controllers are used for this purpose 1 Manually or ii Automatically Manual control Different ways are used in the manual pH control One of them is an operator maintain the juice flow Mt h and SO gas flow compressor air pressure in kg cm rates constant and by adjusting the lime control valve he get the desired value of pH By using the mechanical valve the diameter of the outlet pipe of lime milk tank is changed If the incoming juice flow rates are 85 and 115 Mt h then the diameter of the pipe is 15 and 17 mm respectively In this case raw juice temperature is kept constant The pH value of clear juice is laying in between 6 9 to 7 2 This adjustment is based on the operator experience Such
7. Many stages are involved in the process of sugar production Each stage in turn involves many processes some of which require process controlling for the better end results and yield After a survey of some sugar mills established in western Maharashtra India it has been found that the result of many processes depends largely on human experts Some sugar industries attempts for the conventional automation but have not given the desired results As such even today sugar factories heavily rely on the manual control of various processes hence fuzzy logic is used 1 1 Clarification and pH of juice For the clarification of raw juice hundreds of materials have been tried But maximum sugar industries in India use the lime defecation and sulphitation processes to get clear juice The juice becomes clear after defecation and sulphitation where it is at neutral level i e its pH is about 7 The raw juice pH leaving the mills is generally in the neighborhood of 5 1 to 5 5071 40 B T Jadhav G G Tengshe A B Kulkarni R R Mudholkar and S R Sawant Defecation Procedures e Cold liming Lime is added to a pH of 7 2 to 8 3 and then heated e Hot liming First heated and then lime is added to a pH about 7 8 e Fractional liming with double heating Liming to a pH 6 2 to 6 4 then heated up to boiling and re liming to a pH 7 6 to 8 2 and reheating for settling e Liming while boiling After boiling juice sample is cooled then pH is observed
8. fluids of unit Measurement of weights in Fig AH mim of water Up Expl y ym wg Model Cm head Model Fluid are to be replaced Equation Accuracy Range i by the following mm mm 0 Yn Yn O GTT4B 34 56 1 A water Yu Tm 401768 3536 0 01496 29 92 lH air coy Ys water Yw i Ym Rp ee a 0 01516 30 32 water 000110 2 20 0 00130 2 60 Q01486 2972 Eq 7 96 0 01496 39 92 m E eee es ae s Note The notation Ym 13 6 yy and y 0 0012 gmifem are unit weights of mercury water and air respectively It is assumed that A Ar Ag A and Ag WA O and AR or AZz is measured with an accuracy of 0 001 mm and its range is up to 2mm Table 1 Some Models of Micromanometers and their Resolutions Accuracy Range of Measurement NOTE A patent is pending on the product of digital micromanometers developed and presented in this paper Those who are interested are advised to contact the author for more details REFERENCES 1 Brow J E and Schwertz E A A simple micromanometer Rev Sci Instrum Vol 18 pp 183 1947 2 Duncan W J On a Modification of the Chattock Tilting Pressure Gauge Designed to Eliminate the Change of the Zero with Temperature 1 Sci Instrum V 4 pp 376 1927 3 Hodgson J L A Sensitive Micromanometer J Sci Instrum Vol 6 pp 153
9. 2109 6F 9 210A 80 Point 210B 00 Blank 210C 40 Dash 210D 73 p 210E 76 H 210F 00 Blank 2110 00 2111 00 2112 00 2113 00 2114 00 2115 00 2116 00 2117 00 2118 00 2119 00 211A 00 211B 00 211C 00 211D 00 211E 00 211F 00 2120 79 E 2121 50 r 2122 50 r 2123 5C o 2124 50 r 2125 00 2126 00 2127 00 2128 00 2129 00 212A 00 212B 00 Microprocessor Based pH Measuring System 83 e Sending the equivalent seven segment code of the contents of registers D and E e Subroutine to check the data received is within the defined range or not e Subroutine to send the message Error to the display when data is out of range e Seven segment equivalent codes for the pH values of 0 to 9 point blank dash p H blank spaces Error and blank spaces The assembly language program developed for this system is given in the Table III 7 RESULTS AND CONCLUSION The sample results generated by this system are given in the Table IV The results are comparable with the pH measured by the laboratory meter By corresponding changes in the software the system is able to measure the pH in the two decimal digit forms Such type of system is suitable for laboratory applications to measure the pH of a solutions having fixed temperature By adding the extra circuitry and proper tuning of the parameters we utilize this system for pH controlling applications Further improvement is that we are going to utilize the micro controller in place o
10. 7158 715A 715D 7200 7202 7203 7205 7206 7207 720A 720D 720E 720F 7210 7213 NEXTI DEND D4 CHECK Error DENDI D5 Microprocessor Based pH Measuring System 81 MVI L OI MOV AM OUT 14 DCR C MOV LB MOV AM OUT 14 DCR C MVI LOA MOV AM OUT 14 DCR C MOV LE MOV AM OUT 14 DCR C MVI L OB MOV AM OUT 14 INR L DCR C JNZ LXIHFF FF DCX H MOV AL ORA L JNZ D4 C2 94 70 JMP START Subroutine LDA 2800 CPI 3A JC Error CPI C6 JNC Error JMP CONT Subroutine MVI L 20 MOV A M OUT 14 INX H DCR C JNZ DENDI LXIH FF FF DCX H MOV A H ORA L JNZ D5 JMP LI 2E 01 directly and data is stored in L TE now D3 14 OD Second bit of 2 digit or first bit OD of 1 digit data is displayed TE Display point 1 Display fractional part which is in register E 7C Delay C3 DA 6F To check the data received is within the defined Ranee or not 3A or gt C6 3A 00 28 FE 3A DA 00 72 FE C6 Data less than 3 AH Data greater than C6 H C3 66 70 to send the messaee Error to the disolav when data is out of ranee 2E 20 TE D3 14 23 OD C2 02 72 21 FF FF 2B 7 Delay B5 C2 OD 72 C3 DA 6F 82 B T Jadhav Y S Shinde B B Godabale and S R Sawant Te Display Memory Seven segment Seven segment equivalent code location equivalent of the data 2100 3F 0 2101 06 1 2102 5B 2 2103 4F 3 2104 66 4 2105 6D D 2106 7D 6 2107 07 7 2108 7F 8
11. 98 10 11 A Vimala Juliet and S Renganathan Wallace E Larimore Automated multivariable system identification and industrial identification ACC Proc 1999 p 1148 Wallace E Larimore Optimal order selection and efficiency of canonical variate analysis system identification Proc 13 IFAC World Conference vol I p 151 Wallace E Larimore System identification of feedback and casuality structure using canonical variate analysis IFAC SYSID 1997 Fukuoka Japan July 8 11 1997 p 1 Wallace E Larimore et Al The ADAPTx software for Automated multivariate system identification IFACSYSID 1999 Santa Barbara p 1 Peter J Diggle Time series A Bio statistical Introduction Oxford science publications 1990 p 21 J Instrum Soc India 35 1 99 105 DESIGN OF AT89C52 MICROCONTROLLER BASED SYSTEM FOR THE MEASUREMENT OF TEMPERATURE AND CONTROL A Rajendran and P Neelamegam Research amp PG Department of Applied Physics Nehru Memorial College Puthanampatti Tiruchirappalli Tamil Nadu 621 007 Research amp PG Department of Physics A YYM Sri Pushpam College Poondi Thanjavur Tamil Nadu 613 503 ABSTRACT An AT89C52 microcontroller based system is developed to measure and to control temperature for conductivity studies of liquids The system improves the accuracy of recorded data eliminates varying degrees of human participation and saves operator time Software program
12. A set of 8 pairs of specimens is included in the present investigation of which 4 pairs are tested with 20um aluminium foils and 4 pairs without a foil It is concluded from the results of the present investigation that the enhancement of contact conductance as a function of contact pressure is relatively high in the range of 0 1 to 4MPa when compared to that in the range of 4 to 10 MPa This can be attributed to the transformation from plastic to elastic deformation mode due to work hardening of contacting asperities within the range of applied pressure The measured contact conductance of bare joints is less when compared to the joints with metallic foils under the same set of conditions Effect of Al Metallic foils on Thermal Contact Conductance across Contacts of Stainless Steel 304 121 As the experimental results of the present investigation are encouraging further experiments are planned and some are underway The effect of other types of interstitial materials like coating greases and gases are being investigated using the test facility The results of these tests will be published in future There is a scope for developing mathematical models as the experimental results are available for comparison ACKNOWLEDGEMENT The authors would like to thank the management of Sreenidhi Institute of Science and Technology SNIST for the financial assistance to develop the test facility The authors would also like to thank Prof P Narasimha Red
13. Heat flux meter Top H2 Heat flux meter Bottom S1 SS 304 specimen Top S2 SS 304 specimen Bottom 110 V Vasudeva Rao R Raghukulender and M V Krishna Murthy 5 MECHANICAL LOADING SYSTEM The mechanical loading system consists of a C frame that grips the test column with a spindle above the loading pin and a base plate at the bottom of the test column The applied pressure is transmitted along the axial direction of the test column This is ensured by the two pairs of ball and conical seating arrangement one at the top and other at the bottom of the test column The load on the test column is varied by adding the dead weights to the lever attached to the C frame Proving ring that is attached to the spindle of the frame senses the load that is transmitted to the test column and the load indicator displays the load in kN The C frame described earlier takes care of the reactive forces developed during loading 6 HEATING CIRCUIT The heating circuit consists of a servo stabiliser of 3 k V A rating single phase dimmerstats of 0 to 250V range with 8Amps rating analog Watt meters of 0 to 600W range The heat generation in the heaters is by simple ohmic heating The source temperature can be varied from room temperature to 250 C by changing the input voltage to the heater element by regulating the dimmerstats 3 kV A continuously varying servo stabiliser incorporated in the heating circuit maintains the output voltage at 230V with a var
14. maintained in a steady state condition for a period of 30 mins and numbers of readings were taken at the rate of 2 data per second The deviation observed during thermocouple calibration is within 0 7 and deviation from uncooled probe reading is within 0 54 The probe has successfully used for 100 hrs without failure Constant modification has been carried out to minimise the error to a great extent ACKNOWLEDGEMENT The authors are grateful to Shri A Raju and team of Compressor group to carryout the pressure calibration and also grateful to Members of Heat transfer Group for the assembly and testing of probe NOMENCLATURE HPTNGV High pressure turbine nozzle guide vane Tm Probe stem temperature V Velocity Cp Specific heat at constant pressure T Static temperature Y Specific heat ratio M Mach number AT Temperature difference r Recovery factor T Junction temperature Test probe T Total temperature of gas REFERENCES 1 Aerodynamics Measurement by Robert Dean h Heat transfer coefficient D Diameter of thermocouple k Thermal conductivity L Length of thermocouple Tw Wall temperature Ps Static pressure p Density P Test probe total pressure q Dynamic pressure Po Master probe total pressure a Stefan Boltzman constant 2 3 4 Agard AR 245 Year June 1990 Recommended practice for measurement of gas and temp Heat transfer and application Year 1999
15. 0 1 962 0 296 EE 362 4 300 1969 1 969 0 348 1 969 1 969 1 969 1969 0 364 0221 0 369 0 221 1 969 Wor A Vimala Juliet and S Renganathan Table 1 Open loop response data TP Top pressure TRE Top Reflux flaw NIR Maphthu crew rate EDR Kerosene draw este DDR Diese draw rate ITERAR Top pump around rate MPAR Iviidile pump around rale BPAR Iotiorn purnp around rate KSS8 E eroscne smripper stripping steam BSS Bottem stripping scam KDR DDR MPAR BPAR KS 8 BSS 0 000 dal j G 105 0 070 002 Ati 6 251 i 0 005 0005 796 0489 0 009 0 006 0 942 0782 80 3 0 007 0565 0 963 0 015 0008 0 209 1 105 0 017 amp 008 L173 L201 ONT 0 008 2073 340 0 017 D O08 BR bat 015 0007 4775 1857 0 005 4 015 0 007 4 921 1 913 0 004 9015 1 0 007 5 047 1 969 0 005 015 0 007 5131 L997 007 oun 0 006 j 0 043 0006 5 382 2220 0 007 0 040 006 p015 0 005 5382 227 0 007 0 039 0 007 0 05 0 005 5 424 2 360 6007 6 039 007 0 015 0 008 3403 2413 0 007 0 088 0007 0 015 005 5445 2 513 70 00 0 008 0 007 0 018 0004 5445 2 597 0 007 0 038 0007 0 015 0 004 5 445 j 268 0 007 Q038 U 007 wis 0004 5 443 2 778 9 007 0 038 0 007
16. 1929 4 Macmillan E A Liquid Manometer with High Sensivity and Small Time lag J Sci Instrum Vol 31 pp 17 1954 64 10 11 Achanta Ramakrishna Rao Ower E and Pankhurst R C Measurement of Air Flow 4th ed Oxford Pergamon Press 1966 Pankhurst R C and Holder D W Wind Tunnel Technique London Sir Isaac Pitman 1968 Ramakrishna Rao A Seepage Effects on the Resistance Characteristics of Sand Bed Channels Ph D Thesis Indian Institute of Science Bangalore 1979 Ramakrishna Rao A and Vedula S Liquid Bubble Manometer for Low Differential Heads Proceedings Indian Acad Sci Engg Sci Vol 4 pp 87 94 1981 Smith AM D and Murphy J S Micromanometer for Measuring Boundary Layer Profiles Rev of Sci Instrum Vol 26 pp 775 1955 Stalhane O A New Micromanometer J Sci Instrum Vol 11 pp 79 1934 Streeter V L amp Wylie E B Fluid Mechanics 7 ed McGraw Hill Kogakusha Tokyo 1979 J Instrum Soc India 35 1 65 72 4 WAY POWER DIVIDER CUM COMBINER A K Agrawal Mody College of Engineering and Technology Laxmangarh Rajasthan 332311 ABSTRACT A 4 way Power Divider cum Combiner has been analyzed which uses transmission lines Instead of Resistors connected between the various output ports Unlike resistors used by Wilkinson the transmission lines dissipate little power The lengths of the transmission lines are assumed to be a quar
17. 6 31 microns 1 2 mierens Linear 12 0 e 5 0 Thermal Contact Conductance he kWisq m K oo 0 20 30 40 30 60 FO BO 96 100 llb Applied Presure P M pa Fig 7 Comparison of Contact Conductance Vs Applied Pressure for Joints with Foil at the Interface of 1 2um The two curves shown in fig 2 are one with an interstitial material 20 Im aluminium foil and one with out interstitial material It is observed that the insertion of aluminium metallic foil has enhanced the joint conductance Similarly Fig 3 shows the results of a joint with equivalent RMS surface roughness 6 5m The joint conductance with a metallic foil is substantially high when compared to a bare joint Fig 6 and Fig 7 represent the variation of contact conductance with applied pressure for all the data sets with 1 2 6 5 9 5 and 12 5um as equivalent RMS surface roughness with and without an aluminium metallic foil From these graphs it is evident that the use of interstitial material enhances the joint conductance Also from fig 4 and fig 5 it is observed that the rate of enhancement is high in the range of 0 1 to 4MPa when compared to that in the range of 4 to 10 MPa This can be attributed to the transformation from plastic to elastic deformation mode due to work hardening of contacting asperities within the range of applied pressure 5 CONCLUSIONS In the present work 56 data points are obtained and the results are reported in graphical form
18. CAP Li INTL P2 3 RE T Fo oR IN sogis 19 cu PZG STATUS nz B8 PR li a 81pBER eur 2 RE 13 HR BUF OUT 4 PSEN i5 n EZB TEST IN HI 6 TO MOCE D7 5d T RUN AHOLD IN LO amp E osc SEL 54 ose iM COMMON SET eur osc our LCD E SOS ULT Li ATeScS5hNC jasc vias us Fig 2 AT89C52 microcontroller and 12 bit A D converter Design of AT89C52 microcontroller based system for the measurement of temperature and control 101 integrating 12 bit A D converter which can make 30 conversions per second It is used to convert the analog temperature into digital values B to B and B to B 12 bit sign and overflow signal of ADC 7109 are connected through port 0 A 4MHz crystal is connected in between the pins 22 and 23 The LBEN and HBEN signals are used for reading lower byte and higher byte of digital word of ADC 3 In the higher byte we get the four bits of the most significant data on D D and also the polarity and over range indication on bits D and D The pin 29 generates the internal reference voltage As recommended by the data sheet a preset of 25K is connected between pin 29 and 5V A tap from reset is given to pin 36 the reference input pin Pins 30 32 are for auto zero circuit components This IC uses 5V and 5V power supply The output signal from the thermocouple after amplification is connected to the pin 35 of AOC 7109 through 1 MQ resistance to convert analogue signals to
19. K NM SD PM T PL 10 i 12 13 14 15 1G 7 18 19 LEPVOD Fig 2b Membership Functions 2 2 Knowledge Representation The knowledge pertaining to the pH control strategy is structurally formulated in terms of situation based action rules These refer to the required information from database The knowledge base is thus composed of rule base and database 2 2 1 Data Base The database provides the required infqrmation kept in data files to Fuzzification Inference Engine and Defuzzification modules This includes e Membership functions representing the meaning of linguistic values of pH and Lime Flow Pipe Valve Opening LFPVO in mm e Labels of fuzzy sets representing linguistic variables e Operating ranges Universe of Discourse of linguistic variables Typical membership functions for pH are defined as follows Hyi pH L 6 71 6 83 u pH A 6 71 6 83 6 91 Hyu PH A 6 83 6 91 7 10 Hp PH A 6 91 7 10 7 17 Hy pH A 7 10 7 17 7 21 pH A 7 17 7 21 7 33 Ha pH T 7 21 7 33 Typical membership functions for Lime Flow Pipe Valve Opening mm are defined as follows I LF L 12 13 ULF A 12 13 14 IL LE A 13 14 15 uSD LF A 14 15 16 44 B T Jadhav G G Tengshe A B Kulkarni R R Mudholkar and S R Sawant LU LF A 15 16 17 Jip LF A 16 17 18 ua LF r07 18 User can carry out the tuning of membership functions to suit well to his contro
20. LE 2 Rosa d LET 5 era n Hn an ante dn E r di Lr a xa 28 i TESI GENETTE 2 t n Eum A c To 1 Y n x j E oL xz 3 H E i romae a i aaa gu f Ep une Ada ee Ua S re 94 A Vimala Juliet and S Renganathan S No Manipulated Variables Range Operating point Top pressure Top reflux flow rate Heavy naphtha draw rate 0 73 25 Kero draw rate 0 260 92 M hr Diesel draw rate 0 200 82 M hr Top pump around draw rate 375 middle pump around draw rate Bottom pump around draw rate Kerosene stripper stripping rate 1 2 1 25 Ton hr Bottom stripping rate 0 6 4 Ton hr Table 2 List of Manipulated Variables and their units S No Control Variables Range Operating Unit point an Top product temp 0 200 C 2 Heavy Naphtha draw temp MPA kerosene draw temp BPA diesel draw temp Bottom level 0 400 Table 3 List of Control Variables and their units Lag p is determined by fitting Auto Regressive models with eXogenous inputs ARX as given in Eq 1 p p d Yi EaY i E BU Enjj D i 0 1 0 j l where p is the past lag and d is the polynomial degree and are determined by fitting procedure a D and y are the estimated coefficients a O O Q al 2 B D B p riai B 3 T 2 n T n Nl 4 In CVA computation the AIC
21. Lo 8m8 Vi VD for Bm Zm Bn SC SC g has been simulated ml Om Floating inductor of value L C g Floating inductors which are difficult to simulate with op amps are very easy to be simulated by the use of OTA The only task is to lift the inverting gm1 terminal of fig 7 off the ground and devise a circuit that generates I I at the second impedance terminal Fig 8 shows a simple method which needs only one additional OTA 6 Prasant K Mahapatra Manjeet Singh and Neelesh Kumar Fig 6 Simulation of floating inductor 12 4 DERIVATION OF OTA C FILTERS FROM PASSIVE FILTERS We have considered two cases to visualize our design methodology First order low pass filter 1 Passive Filter Consider a first order low pass filter as shown in fig 9 below I R Onw OO E A i T OMM 9 3 Fig 9 First order low pass filter passive filter 1 And V 14 Realization of Active filters using Operational Transconductance Amplifier OTA After substituting the value of Z from equation 14 into equation 1 we have V 1 CR T s 15 Va S 1 CR Realization using OTAs From fig 10 we get 7 2 g V V 16 From equation 16 and equation 14 the transfer function for considered filter is gc gm o 17 S g C Fig 10 First order low pass filter active filter Passive filter Now consider a low pass filt
22. PI controllers thus obtained were as primary controller K 2 3 and K 0 0001 secondary controller K 0 46 and K 0 008 The NNC was implemented using the direct inverse model of the CSTH process The equations of CSTH were solved using Runga Kutta 4th order method Thirty five random combinations of plant inputs were generated and the system response was obtained for each combination using the numerical solution Eleven samples at regular time intervals were taken from each response Thus 386 training samples were generated to train the NNC ANN Controllers for Industrial Temperature Control Systems 51 ii B Lj pupi Tem pami eo e E ai Hl m Xn dud Tug Bop Aue e Sample dumber a b Fig 2 Multistep Tracking Performance a CFC and b NNC for Water Bath System A three layered neural network having 10 hidden neurons and two output neuron was used The input layer consisted of 6 neurons to account for the inputs F Ti Tji tank reference temperature and previous tank and jacket temperatures The backpropagation algorithm was used for training the controller The learning rate was fixed at 0 0 I The training was stopped once the sum squared error goal 0 001 was obtained Then the NNC was configured as a direct controller to control the CSTH 4 RESULTS AND DISCUSSION Three sets of experiments were conducted on the processes A multi step reference was used to test the ability of the two controllers with resp
23. R 12 Grounded Resistor R Consider fig 4 below which visualizes the simulation of grounded resistor R Applying KCL at node A we have J g V 4 m m Substituting equation 4 in equation 1 we have Z 1 5 Fig 4 Circuit for simulating a grounded resistor R 12 4 Prasant K Mahapatra Manjeet Singh and Neelesh Kumar Floating Resistor After analyzing figures 5 amp 6 we have Ty gy V V 157 Smo V V But J and J I Thus from equation 6 and 7 if g Sm g we have I L Grounded Inductor Fig 7 shows the resulting circuit for grounded inductor if we choose Z Here it can be concluded that J g V Fig 5 Floating resistor R I g for g gm g 15 R 1 g Fig 6 Equivalent circuit of floating resistor 12 6 7 1 SC 8 Realization of Active filters using Operational Transconductance Amplifier OTA 5 and Ja I I This expression reduces to J 7 9 as I 0 By substituting value of J in 8 we have J gV ml 1 But we know that V f X denas 1 ane 10 SC So we can say that Z NO 11 Sm 8m2 The standard form of representing inductive reactance is Z SL Hence we have L 12 Emi 8m2 This inductor is electronically tunable by varying g where i 1 2 amp Matched Fig 7 Simulation of grounded inductor 12 Floating Inductor From fig 8 we have L g g V V and
24. The CSTH and its NNC and CFC are described in Section III The results obtained are then discussed in Section IV Finally the conclusions are drawn in Section V Primary Controller Secondary Controller Secondary Loop Primary Loop Fig l General Block Diagram of Cascade Control Scheme 2 WATER BATH TEMPERATURE CONTROL SYSTEM The water bath system consists of a water tank in which cold water is entering from one side and heated water is leaving from the other The capacity of water tank used is 12 liters The water in the tank is heated by a 2500W base heater A stirrer rotating at 120 rpm is used to ensure even temperature distribution A transport delay 30 sec has been incorporated into the mathematical model of the system The inlet water temperature is taken as 25 C The volume of water is assumed to be constant and therefore the inlet flow rate is equal to outlet flow rate and is maintained at 1 liter min It is further assumed that there is no change of state The set point for output tank water temperature is equal to 40 C The equation defining the system is given below dT E ih TD 2 0 1 dt V Vor fe where T and Ti are tank temp and inlet temp F is the water flow rate V is the volume of the tank Q is heat input p and cp are the density and heat capacity of water respectively The CFC was implemented using MA TLAB and SIMULINK The sampling time of 30 sec was used in the simulation
25. and improved user interface for better operations MAIN MENU Fig l Main Menu Figure 1 shows the main menu of the Real Time RT system developed on virtual environment graphical programming The main menu has four pull up menus sub menus They are LOGIN CONFIGURE PROCESS and QUIT as shown in Figure 1 The main menu was needed a valid password id identification to LOGIN for entering into other menus Therefore the software operations of RT system were protected from unauthorized operations Figure 2 shows configuration menu of the RT system The configuration menu also needs a valid password id for working on this menu The configuration menu was played a major role in data acquisition and analysis The configuration menu was facilitated to configure various underground sensors from remote surface RT system The configuration of various sensors was includes location of sensors in underground along with chock number type units date of installation date of replaced initial readings data acquisition rate warning limits name of the data file and number of sensors as shown in Fig 2 Each Field Point FP I module of data acquisition system was interfaced to 8 sensors Figure 2 and 3 Therefore this configuration menu can support to configure 40 sensors The capacity of the configuration menu can be extendable The data processing menu Figure 3 was followed the configuration Graphical Programming Applications to Data Acquisition 1
26. are day to day becoming more and more difficult as mining has extended to deeper horizons resulting in more adverse geo mining conditions This situation obviously demands more and more sophisticated and advanced instrumental checking for monitoring of the strata and supports behavior Therefore the authors were successfully developed a real time system indigenously for improving efficiency of longwall operations However this paper will discuss the innovations in user friendly menus of RT system LabVIEW is a graphical programming language that uses icons instead of line of text to create applications The software was successfully developed on LabVIEW environment for data acquisition and analysis The software programs were incorporated in Real Time System for acquiring data from underground sensors The PXI real time system was successfully commissioned in one of the Indian coal mines for continuous monitoring and analysis of longwall powered supports behavior in real time First time the RT system was successfully developed and applied to Indian mining applications This paper will discuss various software menus developed under LabVIEW programming environment to facilitate user friendly operations for effective data acquisition and analysis 1 INTRODUCTION The tremendous potential of longwall mining can be realized only if adequate ground control is maintained Barczak amp Oyler 1991 Longwall mining technology very much proven world wide c
27. be displayed is sent by the microprocessor over B port followed by an appropriate number at the C port The value at C port is decoded by a 4 to 10 decoder to generate latch i m 7 segment displays BCD to 7 segmenk Decoders Latches B B3 B4 B7 co ci Latch Enable 4 to 10 decoder Fig 3 Block Diagram of Display Card Design of Decoder for IRIG B Time Code 37 pulse corresponding to the digit where the data is to be displayed The entire data stream is sent over B port in quick succession and each byte is followed by the generation of the corresponding latch pulses This enables the numbers to be displayed 3 3 Interconnections The IRIG B time signal TTL level to be decoded is fed to the Serial Input Data SID pin as well as to the interrupt pin RST 7 5 of the CPU 8085 The 8 lines of B port of 8255 are connected to the data input lines of the display card The 4 lines of C port C0 C3 of the 8255 are connected to the input lines of the 4 to 10 decoder of the display card 4 SYSTEM SOFTWARE The assembly language program is written into the EPROM The instructions for the Main Program and the Interrupt Service Subroutine RST 7 5 when executed perform the following tasks 4 1 Main Program The ports Band C are initialized as output ports In addition certain RAM locations used as counters are initialized These co
28. hand book of thermal conductivity for a given constant heat input Proving tests are conducted and the experimental setup is free from directional bias when compared to the earlier test facilities ACKNOWLEDGEMENTS The authors wish to acknowledge the Department of Mechanical Engineering for providing the facilities to this project The authors also wish to acknowledge Sreenidhi Institute of Science and Technology for funding the project REFERENCES 1 Fletcher L S Recent developments in contact conductance Transactions of the ASME Journal of Heat Transfer Vol 110 pp 1059 1070 1988 Development of a thermal contact conductance test facility 113 Madhusudana C V and Fletcher L S Contact Heat Transfer The Last Decade AIAA Journal Vol 24 No 3 pp 510 523 1986 Fletcher L S Experimental Techniques for Thermal Contact Resistance Measurements Experimental Heat Transfer Fluid Mechanics and Thermodynamics M D Kelleher et al Editors Elsevier Publishers pp 195 206 1993 O Callaghan P W and Probert S D The Effects of Transverse Heat losses on Longitudinal Heat Transport Observations Transactions of the Institute of Measurement and Control Vol 4 No 3 pp 25 T34 1971 O Callaghan P W and Probert S D An Improved Thermal Contact Resistance Rig Transactions of the Institute of Measurement and Control Vol 5 No 8 pp 311 315 1972 Snaith B O Callaghan P W a
29. in fail safe condition it will be in closed condition 5 2 Actuators Actuators used for ball valves in transfer amp weighing system are spring return types so that if power or air fail these valve will close in fail safe condition Design of a TDI transfer and weighing system 33 5 3 Interlocks and Logics Interlocks amp logics for operation are made for each and every operation and redundancy is given in control logic so that even in case of one of the instrument malfunctioning other instrument will take care As an example in case of Level transmitter malfunctioning the weighing machine will take care of safe operation as only exact quantity will be filled in the container and no liquid spillage is ensured For operating this system PLC amp SCADA system is used to make environment user friendly and to improve process control In the present case as I Os are not many PLC works out less costly and is used instead of DCS Distributed Control System Instrument used are of smart type transmitter with HART protocol Calibration of these transmitters is easier than analogue transmitters Smart transmitters have built in diagnostic and hence will be easy to diagnose in case of any malfunctioning of instruments 6 TEST RESULTS Trial run using toluene was undertaken to validate the design The functioning was found with an accuracy of 10gm for weighing up to 5kg The equipment was adopted to TDI after fine Pill tuning of control va
30. in the digital form and stored in the memory The pH reading is displayed on the microprocessor display by proper calibration of digital data and initialization of IC 8279 With proper logic and software support a pH measuring is achieved Microprocessor Based pH Measuring System 75 3 HARDWARE 3 1 Sensor We used the combined Electrode as a pH sensor because it is very easy to manipulate and process it as well as it is possible to fill the reference chemical again and again hence it is cost effective 2 Sensor generates the voltage at its output terminals in mV range which is proportional to the concentration of the H ion in the solution The output of sensor depends on the temperature of solution in which it is dipped and the variation in the output voltage is 0 019V pH degree Celsius C For unit change of the pH value it s output changes by 49 m V at room temperature 25 C The output of sensor is 0 mV at 7 pH amp it gives ve output voltage for pH values less than 7 and ve output for pH values greater than 7 The total voltage variation range is 343 mV OmV and 343 mV for pH values 0 7 and 14 respectively The variation in output voltage is almost linear up to 100 C so it is easy for calibration but at higher temperature variations increases Initially this sensor is tested in the Elico based pH meter 3 2 Isolator follower As the pH sensor does not have any current driving capacity it requires the voltage controlled or v
31. pois 0004 5 466 2 848 0 007 0 038 D 007 wors 0 004 5 466 2 960 0 007 0 038 0 007 W015 0 004 5 487 3 058 6 038 0 007 0 015 0 004 5487 3 141 0 038 U 007 0015 0 003 3487 3211 0 038 DAOO7 0 015 0 003 5487 3295 maag 0 007 0 015 0 003 5 487 3351 uL C038 D o07 0015 i ihia 4467 3 421 3 9 038 0007 0015 0 003 5467 3 490 0038 0007 0 015 0 003 5 487 1 546 38 0007 0015 0 003 5487 3 574 0038 0007 o 01s 0 003 S 4x7 3 602 TT a Ss TE pt eee ae ater dar Modeling of middle product of a distillation column using akaike information criteria 93 SIME IE LYA Re DI Us e IIR SIXE X ani rope sp 34 Edad Arp SSS Oy apppi y je apeas aanp Spek da sive sp8nr Da T Ea F r _ 3 5 em T T x amp mor UwOR m z a nisu enn x apap Kanal tml E r tr u E Y 1 1 i p s E i A 1 1 M aver es pi AAD aS 00332044 SPE A EE Y HR Biagi eric audam er vei Lar TIR m I as qr3 lai ama a toot Eno 3 t F se tS l AZ MAKAN aD IRS oe STU Bye nn RI EP PaKa di acp i u 4 dz ur MEE culos ap w l ace X SSS pe v Eo pqgniea pore mz 1 ni aces days menyesal acp atasodeq ayy jo esucdisaa adeo udo ay iie aig 1 Bly Camas HE eseme 4 E r APADI MISR PAIN ba Ph Aa
32. probe which was calibrated with tracebility to National standard by a third party A dedicated data acquisition system by M s Scanivalve is used for this purpose The calibration of test probe was carried out for a Mach no range of 0 3 to 0 67 The different set points and percentage error obtained during the calibration is given in Table 1 Fig 3a and Fig 3b shows the typical graph of recovery factor vs Mach number and error vs Mach number 4 2 Temperature measurement The various errors estimated as follows 4 2 1 Velocity error The velocity error estimated for Mach number 0 15 is 3 33 C Set Mach No Master Test probe Recovery No Probe pressure P factor Pressure Po psi P Po D si 4 04608 13 907 13963 1 884 0 9997 021 6 0 5462 144001 14369 2636 09977 121 8 0662 15314 15305 3 895 0 9994 0 23 9 oe 16586 16 571 4925 09990 034 Table 1 Pressure Calibration report Recovery factor PIPa error P Po iq Design and development of water cooled probes to measure pressure and temperature 25 0 095 0 08 0 085 5 E 0 976 37 D a 0 35 4 O45 O35 0 55 DE 0 65 Di Mach No Mach No Vs Recovery factor Fig 3a 1 5 0 3 0 35 0 4 0 45 0 5 0 55 0 6 0 65 0 7 Mach No Mach No Vs error Fig 3b 26 K Anil Kumar S A Vasudev and Meera Kaushal 4 2 2 Conduction error and Radiation error Th
33. the earlier paragraph As such in the present system TDI is initially transferred from drums to intermediate storage tank by vacuum through a trap vessel so no TDI vapour escape into the atmosphere through vacuum pump Intermediate vessel is used as storage vessel for TDI and is positioned at a height so that gravity head can be used in subsequent transfer processes The required quantity is transferred to the measuring vessel by gravity through seal pot so that no air from atmosphere come in contact and contaminates the TDI inside the system Measuring vessel is found necessary as storage capacity of intermediate vessel is 300ltr and transfer of 1 5 kg per batch can not be directly controlled with 10gm accuracy A P amp I diagram is given in figure I The logic and design step details are given below under different sub sections 4 1 1 Main storage to intermediate tank The steps involved are as follows a System to check whether level is up to mark or not in the trap vessel and if it is okay then only the vacuum pump will start b Check the level of TDI intermediate tank level and only if level is up to the mark vacuum ball valve will open c Drain valve of intermediate to be kept closed TDI storage drum to be kept at the position and dip rod inserted manually into it After this valve in transferring line 31 Design of a TDI transfer and weighing system ajpupn amp oosn q auanjoy 4of ui2js amp g Sulysiay P 42fsuDAT
34. then passes through several filter stages A stable DC output is obtained at the last stage This DC voltage is fed to a digital display which displays the distance between the transducer and mercury meniscus directly in mm Block schematic diagram of the instrument is shown in Fig 2 The signal output can be connected to a computer through a data acquisition system for a continuous recording of data Turbulent fluctuations in the experimental fluid flow are expected to transmit through the manometric circuit and finally in to the signal output Hence provisions are made in the circuit to suppress such minor and continuous fluctuations in the signal to get a stable readable display AC DC converter Filter Amplifier Detector Fig 2 Block Schematic Diagram of Signal Processing The capacitive transducer thus developed has a range of up to 2 mm and a resolution of 0 001 mm It may be noted that the range of measurement can be increased by increasing the cross sectional area of the probe M as well as the cross sectional area of the sump S according to capacitance principle The operating range of temperature is 8 C to 40 C 2 3 Working Principle Due to the application of differential pressure the level of manometric fluid of unit weight y in sump S lowers by a distance of AZ where as its level in sump S rises by AZ compared the datum O O As a consequence the levels of the manometric fluid of unit wei
35. to open Feeding valve to intermediate tank to be closed If level of measuring vessel shows low level then bottom valve of intermediate tank to open As level in measuring vessel reaches to set point ball valve to measuring vessel to close 4 1 3 Filling amp weighing of TDI in container a b c d System to check the readiness of vent seal pot Weight of TDI to be filled in container has to be entered in SCADA and place the container on the weighing machine Vent valve of measuring vessel to open Ball valve to container open only after the measuring vessel bottom control valve gradually open and filling starts The control valve gradually closes as weight of filling container approaches to its set point Ball valve and control valve both close as the required weight of TDI is filled in the container 5 EQUIPMENT AND INSTRUMENT SELECTION IN THIS SYSTEM 5 1 Control valves Leakage from control valve is one of the major bottlenecks in manufacturing process and as TDI is carcinogenic in nature even in low concentration control valve used in this system has to be selected with utmost caution Leakage from globe type valve is from the stuffing box However in bellow seal type valves bellow element act as a protective cover for valve stem and no liquid or gas will be in touch with valve stem Hence there is no possibility of leakage of fluid through stuffing box Control valve used in this system is of air to open type so that
36. type of technique is used in the Damaji Co Operative Sugar Mill Ltd Mangalwedha M S Auto control In auto control different types controller s used to maintain the desired pH values Some sugar industries use the electronic controller to control the pH to the required value by adjusting the lime flow amp SO gas flow rates simultaneously and the raw juice flow rate is kept constant Here only one pH sensor is used to observe the pH value This type of controller is utilized in the Ajinkyatara Co Operative sugar Mill Ltd Satara M S In Kumbhi Kasari Co Operative Sugar Mill Ltd Kuditre Kolhapur M S pH value of clear juice is maintained to the desired level by adjusting the lime flow rate but in this case SO gas and raw juice flow rates are constants In this microprocessor based control system Fuzzy logic pH controller in sugar industry 41 two pH sensors are used to sense the limed juice pH and clear juice pH The chemist decides these pH values The stepper motor is used for valve adjustment of lime flow In another auto controller raw juice and SO gas flow rates are kept constant Only clear juice pH is sensed and maintain by varying the lime flow rate using stepper motor valve adjustment technique Some sugar factories initially keep the raw juice flow rate constant and adjust the lime flow rate to get the pH up to 9 6 to 10 5 for alkalinity Then SO gas is bubbled to reduce the limed juice pH value about 7 The SO gas f
37. 14 70 A K Agrawal Zi j Z2 z zyput 22 6212 Z383B a Fig 3 Power Combiner Circuit 5 ANALYSIS OF POWER COMBINER Fig 3 shows the Power Combiner circuit with assumed voltage and current waves The voltages and currents at the nodes are V B Vue V te L V tet Vre ZI Viet e Vte 4Zg V Vit V V V Vg V 30a L V tet Vre ZI Viet V e 4Zg A LZ WV V pA D b V2 e V2 e Z2 V V Z From 29b V 4Zg Z 4Zg Z V e Substituting for V in 30a V V Vi Ie 4Zg Z 4Zg Z e V or V V2 1 4Zg Z 4Zg Z e From 31a and 31b Ve L Z4Z 2 Z V V Z Ve L Z Z 29 V Vy V QZ Then 30 becomes V V Vy L Z cosd jZ sing jZ V V sino 2 Z V V7 L Z coso jZ sinp Z V Vy sin o 2Z From Fig 3 L L Y Y V V Z V Z 29 a 29b 30b 31a 32 33 34a 34b 35a 35b 36 4 way power divider cum combiner Substituting for Y From 6 v V LY Yin jY tant IY Z Y Y j3Yin n 3Y Yin E 21 2 Substituting for Yin From 15 into 37 IY V OZ EHD L GT3 62 72 Substituting 38 into 35 V Vy Vs j T GRET 2 k 3 Voy jZ I Substituting 39a into 33 j L 37 44g Z From 32 Seen vo Lc R7 Zz Z From 29b A K 3 j L 3k 7 Z cost jd Zz sin
38. 3 menu to produce results Consequently the configuration menu was a very important menu in successful real time operations Ceased nn ee dm Fig 2 Configuration Menu 1 18 E E Meet Ped ip orsus E smm u iep E or sities Fig 3 Data Processing Menu Figure 3 shows the data processing menu of the RT system The data processing menu was output display of RT system as shown in Figure 3 and 6 The data processing menu is also called real time display The RT system was executed the various software routines as per the instructions of configuration menu for acquiring data from underground sensors and 14 Srinivasulu Tadisetty Kikuo Matsui and R N Gupta displayed on data processing menu after analysis The various features of the data processing menu are shown in Figure 6 The data processing menu cannot accept user instructions directly However it follows the instructions of the configuration menu Thus the configuration menu is controlling the data processing menu 4 FLOW OF RT OPERATIONS Enter Valid Password ID Yes Configuration Menu No Configuration Valid Data Processing Menu Yes Fig 4 Flow of major real time operations Graphical Programming Applications to Data Acquisition 15 The major software flow of real time operations is shown in Figure 4 The operator user is required a valid password and ID for operating Moreover he should be familiar with systematic
39. Analysis and Akaike Information Criteria for system identification and reduction in order of a Distillation Column model The optimal model stmcture of distillation column is found using Akaike Information Criteria In the method proposed the statistically significant values are first obtained using Canonical Variate Analysis approach thus providing a mathematical basis for the model The open loop response data are collected from a distillation column Ten manipulated variables are reduced to two which in turn is used for calculation in another refined model 1 INTRODUCTION There are about hundreds of variables related with distillation process out of which five variables are taken as Control Variables and ten are taken as Manipulated Variables In fact a distillation column presents the following characteristics it is a non linear process it is multi variable with strong interactions and it exhibits pure time delays between its input and output variables 1 Consequently the application of Canonical Variate Analysis CVA and Akaike Information Information Criteria AIC for modeling will be a real and challenging one 2 Determining a model using a conventional method is difficult because it needs complete understanding of the process even if it is found it would be with higher dynamics obviously very complicated It would be difficult to determine the appropriate model structure particularly in the presence of unknown feedback Additi
40. Author Kirk D Hagen Published by Prentic Hall Measurements in Flames Year 1972 Authors J Chedaille and Y Braud Published by Edward Arnold Publishers Limited J Instrum Soc India 35 1 28 33 DESIGN OF A TDI TRANSFER AND WEIGHING SYSTEM Arvind Kumar K K Radhakrishnan and V K Bhat High Energy Materials Research Laboratory Pune 411 021 ABSTRACT In the field of Defence and Space the matrix that gives the strength to the solid composite propellant is generally a polyurethane formed by cross linking of telechelic polymer and toluene diisocyanate TDI TDI is widely used all over the globe for propellant manufacturing and also as a cross linking agent in polyurethane industry The use of TDI though may be to the extent of 1 of propellant weight is observed to be hazardous and causes great discomfort to the workers Spillage and exposure are observed to be maximum during transfer of required quantity of TDI from big size drums to smaller containers for further processing Environmental interference due to moisture susceptibility has been found to be a major factor that affects its use as well as quality of the product To reduce the risk and hazard in transfer of such toxic compounds attempts for process automation are continuously made in resin and polymer industries However many of the indigenous propellant plants still continue with the manual system A TDI transfer and weighing system has been designed at HEMRL Pu
41. BES TO MEASURE PRESSURE AND TEMPERATURE IN HIGH TEMPERATURE HIGH PRESSURE ENVIRONMENT K Anil Kumar S A Vasudev and Meera Kaushal Gas Turbine Research Establishment Bangalore 560 093 ABSTRACT The measurement of total pressure and total temperature of gas at the inlet of a turbine cascade is essential during the testing of the cooling configuration of turbine blade A Water cooled probe was designed and developed to operate in a high pressure high temperature environment to measure the gas parameters in the order of pressure 25 bar temp 1700 K and velocity up to 150 m sec The pressure calibration of probe was carried out in the Calibration lab of GTRE at Mach numbers in the range of 0 3 0 6 The temperature calibration to find out recovery factor was not carried out due to lack of a suitable facility but a comparative study was carried out in Heat transfer rig of GTRE with a similar uncooled probe The total estimated uncertainty in pressure and temperature calibration is in the range of 2 4 1 INTRODUCTION In Heat Transfer rig the turbine blade HPT NGV is housed in a sectorial test section immediately after a combustor as shown in fig 1 The aerodynamic flow parameters of gas i e Total pressure and total temperature to be measured between the combustor exit and HPTNGYV in a restricted area but in the same time any insertion in the gas flow path should not create wake effect at the entrance of stator blade which may affec
42. C s LF 356 LM 324 and Transistor BC 109 are useful for signal conditioning The eight channels ADC IC 0809 is suitable to convert the data in the digital form The DAS Data Acquisition System stores the data coming from the sensor The output of defuzzifier is read by the DAC IC 0808 and drives the stepper motor using the driver circuitry The stepper motor arrangement is essential for the opening and closing of the valve at the required diameter Immediately after the measurement of pH the Fuzzy Control takes control of lime milk regulation This involves the following steps 5 2 l e Fuzzification e Knowledge Representation e Inference Process e Defuzzification 2 I Fuzzification The input variable pH and output variable Lime Flow Valve Opening Diameter mm are selected for fuzzification Based on the on line observations the operating ranges are decided and variables are assigned using meaningful linguistic values Fuzzification is carry out by using appropriate membership functions over practical ranges The fuzzy sets so obtained are then labeled using the term set T NL N NM SP SD PM P PH NL Negative Large N Negative NM Negative Medium SP Set pH SD Set Diameter PM Positive Medium P Positive PH Positive High The membership functions are shown in Fig 2 lee NI MOO NM SP PM P TH Fig 2a Membership Functions of pH Fuzzy logic pH controller in sugar industry 43 1 2 j NL
43. Godabale and S R Sawant Convert Data in the MVI H 00 MOV EA MVI A 39 INR H ADI OA CMP E JZ NEXT JC ADD SUB E MOV B A MVI A 09 SUB B MOV L A DCR H MOV A H CPI 0A JC DEC ADI 06 MOV H A XCHG Use Of 8279 hv MYI A D3 OUT 15 MVI C FF DCR C JNZ D3 MVI A 00 OUT 15 MVI A 32 OUT 15 MVI A 90 OUT 15 The equivalent MVI C 08 MVI H 21 JMP Check MOV L D MOV AD CPI OA JC NEXT 1 MOV AD SBI 10 MOV BA Corresponding pH equivalent and Store it 26 00 Sendinff different 3E D3 D3 15 OE FF OD C2 4F 70 3E 00 D3 15 3E 32 D3 15 3E 90 D3 15 Seven segment OE 08 Get data in reg E Load acc With 39H How many times 10 Should be added to the 39H to make it greater than the data received This gives ffactional part of pH Number of times 1 Ifno of times required to make 39 greater are more than 09 i e A OB etc then this is converted to decimal equivalent by adding 6 to it Get converted data in DE Control Words Delay Out various control words Codes for the contents of the registers D and E Go to the subroutine if the accepted data is in range or not Check data in D is greater than 9 or not If the data is greater than 9 then first digit is displayed as 1 7071 7073 7074 7076 7077 7078 7079 707B 707C 707E 707F 7081 7082 7083 7084 7086 7087 7089 708A 708C 708D 708E 7091 7094 7095 7096 7097 709A 7150 7153 7155
44. Hanjura and B S Mathur Satellite Broadcasting of Time and Frequency Signals Proc IEEE Vol 79 No 7 973 981 July 1991 2 P Kartaschoff Frequency and Time Academic Press 1978 J Instrum Soc India 35 1 39 47 FUZZY LOGIC pH CONTROLLER IN SUGAR INDUSTRY B T Jadhav G G Tengshe A B Kulkarni R R Mudholkar and S R Sawant Department Of Electronics Yashavantrao Chavan Institute Of Science Satara M S Department Of Electronics D Y Patil College of Engineering Kolhapur 416004 M S Department of Applied Electronics Gulbarga University gulbarga 585 105 K S Department Of Electronics Shivaji University Kolhapur 416004 M S ABSTRACT The process of pH control in sugar industry forms an important clarification phase But no fixed value of pH can be prescribed however for optimum clarification the desirable figure varies with the type of juice i e with the nature of impurities Rapid changes in pH are likely to give secondary precipitation in the juice in or after sub siders Adjustment of pH is necessary to minimize decomposition of sugars in clarification and subsequent boiling house operation In the narrow limits of pH satisfactory removal of impurities from raw juice is practicable To embed the knowledge of human expert for satisfactory clarity of juice we propose a fuzzy logic pH control technique to maintain the desired level of pH 1 HUMAN EXPERTS IN SUGAR PROCESS
45. J Instrum Soc India 35 1 1 9 1 REALIZATION OF ACTIVE FILTERS USING OPERATIONAL TRANSCONDUCTANCE AMPLIFIER OTA Prasant K Mahapatra Manjeet Singh and Neelesh Kumar Central Scientific Instruments Organization Sector 30C Chandigarh India ABSTRACT The performance of filters designed by the use of passive components degrades at audio frequencies and the required resistances and inductances values calculated from the mathematical expression are very difficult to meet from the market To find a solution to this problem we have performed a study to realize Passive Filters into Active Filters using Operational Transconductance Amplifier OTA By controlling the Voltage Gain of OTA one can change its transconductance which is very useful in the designing the first order and second order active filters In this article we have confined our discussions only to the design of first order low pass filters using OTA It is concluded that the new approach gives us a wide range of tunable cutoff frequencies Basic properties of OTA are discussed 1 INTRODUCTION This paper describes the usefulness of OTA 3 5 over the conventional Op Amp in the design of both first order amp second order active filters as an active element OTA is a differential voltage controlled current source VCCS where the output current is controlled by an applied input voltage signal To achieve any required cutoff frequency in passive filter we require different valu
46. S and S are only used and the remaining two sumps are not needed in the manometer circuit However the sump S which contains the probe M is open to atmosphere In this model also either air or water can be used as an experimental fluid Thus the governing equation for this model with water as the working fluid can be obtained by making use of the conditions of yml ym y yw and as usual the geometric conditions A A A A and A a in Eq 3 as AH AZ Y Y a A Y Y D 7 Hence the manometer constant CM is about 14 86 when y 13 6 gmf cm y 1 gmf cm and a A 0 1 As AZ is measured with an accuracy of 0 001 the accuracy AH measurement is about 0 01486 mm and its range is about 29 72 mm of water head The following equation can be obtained if air is used the experimental fluid instead of water in the fourth model AH AZ y y AAY YY 7a 4 CALIBRATION The working principle of the micro manometer is verified with Eq 7 of the fourth model with mercury and water as manometric and experimental fluids respectively by conducting a calibration test The head H is varied in steps by adding water in to the glass tube of the sump and the corresponding display reading of the capacitance manometer AR in Fig 1 is noted The water level in the glass tube from the sump S is noted by using a powerful traveling microscope with a least count of 0 01 mm Sumps S and S are made out of glass with internal diam
47. The initial values of K K and K the proportional integral and derivative gain parameters of the CFC were calculated using Ziegler Nichols method and were further tuned using hit and trial method The final tuned values of K K and K are equal to 1 5 0 01 and 3 0 respectively For the NNC thirty five random combinations of plant inputs were generated and the response of the system was obtained for each combination Eight samples at regular time intervals were taken from each response Thus a total of 280 training samples were generated to train the NNC 50 A K Goel Manoj Kumar Sharma and Neeraj Gill A three layered MLP was used to implement the NNe The input layer consisted of 4 neurons which account for the F Ti reference tank temperature and the delayed plant output Ten neurons were employed in the hidden layer One output neuron accounted for the lone output Backpropagation learning algorithm was used to train the NNC8 The training was stopped once the sum squared error goal of 0 001 was achieved The trained NNC was then configured as a direct controller to control the process 3 CSTH TEMPERATURE CONTROL SYSTEM The CSTH system consists of stirred tank heater where the tank inlet stream is received from another process unit The objective is to raise the temperature of the inlet stream to a desired value A heat transfer fluid is circulated through a jacket to heat the fluid in the tank It is assumed that there is no chan
48. Yg kYg K 1 11 Using the equations 3 to 8 we obtain 3Y Y Yg Ay 12 kYg 4Y 7 Yg From 11 and 12 Y1 and Y2 are determined as Y 1 Z Yg Yg k 1 2 13 Y 1 Z 2Y Yg k k 2 k 3 14 iti Determination of Y On substitution of Y and Y into 3 4 and 5 Yin Y k43 GY k 15 From 1 the external admittance seen by any one arm at node 4 is Y a Yin Y k 3 Y k 1 16 Hence Y can be suitably adjusted by selecting Y3 and k Y4 it should be small so as to prevent the power from leaking out from any one arm into the three arms of the power Divider 4 ANALYSIS OF POWER DIVIDER The Power divider of Fig 2 is analyzed by assuming voltage and current waves in lines 1 2 and 3 as shown Equating the voltages and the currents at the nodes the following equations are obtained V VW t Vy Vg 41gZg 17 Ig V V Z 18 V VV V te Vv 2 19 L V fZg V te Vv 99 Z V Vy Z 19b 68 A K Agrawal T Wan Fig 1 Power Divider cum combiner V V V Vite V e 20a L V Z V tet V ert S vs VIZ i Determination of V and V From 17 and 18 Zin Vi Ig 4Zg1 2 AZg Z V V HY t Vp Or V V 4Zg Z 4Zg Z 21 On eliminating Ig we get Vg V V V V Z Using 21 Vg 16Zg V 4Zg Z Therefore ve Vg 4Zg Z 16Zg Ve Vg 4Zg Z 16Zg ii Power
49. ances Int J of Circuit Theory and Appl Vol 10 pp 27 42 1982 National Semiconductor Application Note LM 13600 Dual Operational Transconductance Amplifiers with Linearizing Diodes and Buffers Feb 1995 W R Grise Application of the Operational Transconductance Amplifier to Voltage Controlled Amplifiers and Active Filters TECHNOLOGY INTREFACE The Electronic Journal for Engg Technology Vol 2 2 Winter s98 URL http et nmsu edu etti M Bialco amp R W Newcomb Generation of All finite Linear circuits using the Integrated DVCCS IEEE Trans on circuit theory vol CT 18 pp 733 736 Nov 1971 Linear Integrated ICs by Roy Chowdary Sclof Sidney Design and application of Analog Integrated Circuits Chapter 9 3 Prentice Hall Inc Englewood Cliffs N J 1991 Geiger R L and Sanchez Edgar Active Filter Design using Operational transconductance Amplifier a tutorial IEEE Circuits and Devices Magazine Vol 1 Number 2 pp 20 32 March 1985 C F Wheatley and H A Wittinger OTA Obsoletes OPAMP P Nat Econ Conf pp 152 157 Dec 1969 J Instrum Soc India 35 1 10 19 GRAPHICAL PROGRAMMING APPLICATIONS TO DATA ACQUISITION AND ANALYSIS OF LONGWALL POWERED SUPPORTS BEHAVIOR IN REAL TIME Srinivasulu Tadisetty Kikuo Matsui and R N Gupta National Institute of Rock Mechanics Kolar Gold Fields India Faculty of Engineering Kyushu University Japan ABSTRACT Indian mining operations
50. anometers are essential to measure such small pressure heads with high accuracy The author of this paper has faced such a serious problem in his experimental research which had prompted him to develop couple of micro manometers to meet such measuring requirements A Digital micromanometer for very low pressure measurement 55 Such low differential pressures are often measured with a V tube using suitable manometric liquids whose density is very close to that of the working or experimental fluid Micromanometers using two manometric liquids which are immiscible and whose densities are close to each other Brow amp Schwertz 1947 Streeter amp Wylie 1979 are often used for such measurements To improve the sensitivity of the manometers inclined manometers are often preferred to vertical limb manometers although these manometers have their own limitations in use For instance even a small change in the difference of densities of the manometric liquids is likely to cause significant variation in the measurement of head in differential liquid density manometers Also it is experienced that the response of such manometers are slow and sluggish Inclined manometers cannot be effectively used below about 10 of inclination to the horizontal plane because of difficulties in reading and of possible errors due to the alignment of the manometric tube itself Many types of other sensitive manometers given in literature are often delicate difficult to
51. ansmission and thermal resistance Veziroglu et al analyzed Thermal Conductance of Contacts with Interstitial Plates and concluded that the TCC is a function of the properties of plate materials O Callaghan et al developed and demonstrated a theoretical optimization procedure to establish the appropriate interstitial filler material thickness for Minimum Thermal Contact Resistance But their theory is based on the assumption of ideal plastic asperity deformation Cook et al proposed a novel concept for reducing Thermal Contact Resistance by introducing interstitial materials whose melting temperature is slightly more than the room temperature This interstitial material will be in liquid state when the joint reaches the actual working temperature Antonetti and Yovanovich developed a thermo mechanical model that predicts the Thermal Contact Conductance of silver coated nominally flat contacting surfaces Yovanovich in his review on thermal management of electronic equipment stated that the contact resistance problem require simultaneous solution of thermal mechanical and metrological problems Chung et al developed analytical expressions for TCC of cylindrical contact spots for phase mixed metallic coatings using plasma enhanced deposition on to a cold surface Couedel et al used the experimental data on metallic foils tin lead and copper available in the published literature and presented a correlation to determine TCC But these models
52. are successful only to a certain extent due to the assumptions they make Therefore in the present work it is proposed to experimentally determine the effect of AI Metallic foils on Thermal Contact Conductance across Contacts of Stainless Steel 304 3 EXPERIMENTAL INVESTIGATION a Specimen Preparation The test specimens are fabricated as follows Stainless Steel 304 rod of 28mm diameter is taken from a bar stock and machined to 25 mm dia x 25mm length so that the from ratio 116 V Vasudeva Rao A Kumara Swamy R Raghukulender and M V Krishna Murthy is 1 1 In order to measure the temperature gradients in the test specimens temperature measurements are to be made along the axis of the test column with temperature sensors To install the temperature sensors Thermocouples in the present case in the test specimens 1 2 mm dia holes are drilled up to the axis i e to a depth of 12 5 mm such that the depth to hole diameter ratio is about to In each test specimen 3 such holes are drilled with an axial distance of 6 25mm In the present investigation the test specimens are machined with varying surface roughness between one and 10um The contacting surfaces of the steel specimens are specifically designed and generated by turning on a precision lathe The specimens are first cleaned with kerosene and then with soap solution to remove any traces of oil on the contacting surfaces The contacting surfaces are then cleaned with acetone before
53. at 2199C It is trivial to note that all the ten manipulated variables mentioned in Table 1 would affect the process In order to determine the variables that would affect the system most significantly when disturbed detailed statistical analysis has to be performed From the time series data obtained from the open loop response Table 1 the mean and standard deviation for all the variables are calculated and results shown in Table 4 As the table shows the kerosene stripping rate and bottom stripping rate has got the most significant values The variables which have large magnitude affects the process more significantly as pointed by Larimore 8 9 Hence the middle product temperature is most affected when changes are made in these two manipulated variables To build a mathematical model these two variables are used as manipulated variables TP TRF NDR KDR DDR TPAR MPAR BPAR KSSS BSS Mean 1 524 0 237 0 159 0 0043 0 033 0 005 0 015 0 005 4 284 2 323 Std 0 705 0 124 0 066 0 005 0 009 0 003 0 004 0 002 2 08 0 99 Dev Table 4 List of Manipulated Variables and their Statistical parameters The Canonical Yariate Analysis uses singular value decomposition technique on the selected memory length and the rank of the matrix is found which is nothing but the order of the model This order is further used in Markov s process to predict the future values ba
54. at present and easy to fabricate and use however it has a serious disadvantage of slow in operation as its response to pressure variations is slow and normally takes about 5 minutes time to record a single reading Due to the advancements in present day technology pressure transducers hot wire film anemometers laser Doppler anemometers etc are extensively used for measuring small pressure velocity heads But these instruments are prohibitively expensive for Indian conditions Hence there appears to be a need to develop a simple economical and quick responsive micro manometer to satisfy the modern needs Such a manometer which works on capacitance measurement principle is developed and presented here The manometer quickly senses the applied pressures and displays the corresponding reading digitally It is capable of measuring pressure heads up to a maximum of 2mm of mercury with a resolution of 0 0 01 mm It can be attached to a computer through a data logging system for continuous monitoring recording of the data 2 DESCRIPTION AND WORKING PRINCIPLE The micromanometer as a unit consists of three major components namely manometer circuit capacitance transducer and governing equation or working principle They are described here 2 4 Manometer Circuit The micro manometer consists of four interconnected cylindrical glass sumps S S S and S as shown in Fig 1 All the sumps are of uniform cross sectional areas of A A A and A
55. aulic and aerodynamic laboratories especially useful in the measurement of water surface elevations in open channels and velocity profiles in boundary layers Four models with different measurement accuracies of pressure head are presented which show that the measurement accuracy of the pressure head can be achieved from 0 0011mm to 0 0175mm and cover the ranges up to 2 2mm to 35 mm of water head 1 INTRODUCTION In experimental investigations either in hydraulic or aerodynamic laboratories measurement of small pressure variations with high accuracy is extremely important For example the measurement of water surface elevations along the flow direction in an open channel and the measurement of local velocities along the flow depth or boundary layer thickness as well as the measurement of relatively small pressure drops over a pipe flow are some of the challenging tasks in laboratories Generally the magnitude of water surface slopes could be in the order of about 10 thus the water surface drop over a distance of a meter length is only one tenth of a millimeter Many times the local or point velocities along the flow depth in an open channel or even in pipes are to be measured at least with an accuracy of v 1 cm s and this is to say that the velocity head v 2g could be about 0 005 mm of water Hence such measurements demand very high accuracy Thus while investigating the fluid flow behavior either in open channels pipes or wind tunnels micro m
56. c building blocks of R R Grounded Inductor Floating Resistor Floating Inductor and in the fourth section we have confined discussions for the derivations of OT A C active filters from first order passive filters Last section gives the concluding remarks 2 OTA FUNDAMENTALS The OTA is a transconductance device in which the input voltage controls the output current The transconductance gm makes the OTA as voltage controlled current source where as the op amps are voltage controlled voltage source An ideal OTA 12 is defined by 1 7 g V V Where input amp output impedances are infinite The transconductace g is directly proportional to control bias current J Characteristics of Ideal OTA 15 can be summarized as follows Input impedance Z e Output Impedance Z ee Inverting input current J Non inverting input current Bandwidth oo The Figures I amp 2 shows the basic schematic and equivalent circuit of OTA SS Fig 2 Small signal equivalent circuit of OTA 1 Realization of Active filters using Operational Transconductance Amplifier OTA 3 3 BASIC BUILDING BLOCKS USING OTA Grounded Resistor R Consider fig 3 which simulates grounded resistor R using OTA Applying KCL at Node A gives us J I 0 1 where I Vm x gm 2 Substituting the value of Z from equation 2 in equitation 1 we have I Z 3 Eu Fig 3 Circuit for simulating a grounded resistor
57. cal Engineering Progress 55 March 1998 10 Cecil L Smith Process Engineers Take Control J Chemical Engineering Progress 19 Aug 2000 D J Instrum Soc India 35 1 34 38 DESIGN OF DECODER FOR IRIG B TIME CODE A K Hanjura National Physical Laboratory Dr K S Krishnan Marg New Delhi 110 012 ABSTRACT Among the Inter Range Instrumentation Group IRIG time codes IRIG B is most popular worldwide Most of the digital clocks provide this time code as an output This time code can be transmitted over a long distance and needs to be decoded and displayed Transmission can be as potential free contacts or as radio signals The present paper describes the design of a microprocessor based IRIG B time code decoder and display unit designed specially to decode and display time of the day from Standard Time and Frequency Signals STFS transmitted from National Physical Laboratory New Delhi via INSAT satellite for the hundred odd users all over the country 1 INTRODUCTION Inter Range Instrument Group IRIG time codes were developed and used extensively during World War II Out of various IRIG time codes IRIG B time code is most widely used This code carries information on the time of the day hours minutes and seconds and also the day of the year 1 to 365 or 366 Other information in this code is not relevant in the present context IRIG B time code is available as an output in many standard clocks It is general
58. cost particularly because of the accessories attached to it For example in the Chattock gauge one needs a powerful microscope and a fine wheel vernier to keep the oil film back to the zero position When a microscope is used however there appears to be of no need for a tilting arrangement or even the oil film because the traveling microscope attached with a fine vernier can itself measure small differential heads directly on a simple V tube manometer or a piezometer The Chattock gauge has certain serious limitations that the oil film may break during its operation and restoring the film is a tedious job also it has a delicate glass work and also the maintenance required like cleaning etc is not easy The modified Chattock gauge looks attractive due to the mobility of the air bubble which was used as an indicator with xylol as the manometric fluid instead of the middle cup or bulb of the Chattock gauge However the other limitations are not avoided also the flow past the air bubble is possible particularly when there are fluctuations in applied pressures because the air bubble is easily susceptible to change of shape 56 Achanta Ramakrishna Rao Most of the manometers mentioned above find their best use with air as the working fluid For measurements with water however several problems may arise when these manometers are used F or example in open channel flow experiments it is likely that the water working or experimental fluid used may n
59. ctionation as practiced in refineries involves heating the crude to a temperature high enough to effect product separation and heating cost of crude is significant So in order to reduce the fuel cost crude is preheated in heat exchangers with products and pump around streams of unit so that maximum heat is recovered Crude distillation column has two sections The bottom section known as stripping section has 6 trays and the upper section known as fractionating section has 34 trays The vaporized portion of the feed strip out vapours from stripping section and steam emanate from the bottom section rises up the column In order to condense the vapours into various distillate fractions at appropriate zones it is necessary to maintain a temperature gradient across the tower This is maintained by three pump around circuits in the column The Top Pump Around TPA liquid stream is drawn from 37 tray at a temperature of 219 C through a pump This TPA returns to the tower at tray 39 only The cooled TPA returns to tower at a temperature of 94 C The Middle Pump Around MPA and kerosene distillate product share the same tray 20 The cooled MP A at a temperature of 165 c returns to the tower at tray 25 only The Bottom Pump around BPA and diesel product share the same draw tray 12 BPA drawn at 311 C The cooled BPA returns to the column at a temperature of 250 C to the tray 14 Thus TPA MPA amp BPA heat duties have been used to reduce vapour load in
60. curacy and range of AH measurement Also on many times a higher range of AH is desirable at the expense of a lower accuracy This can be achieved by increasing the value of alA i e the ratio of cross sectional areas of sumps S and S such that a gt gt A It may be noted that A gt gt a in the previous models For an example if a A 10 the manometer constant C becomes 11 and thus the accuracy of measurement of AH is now reduced to 0 011mm and its range is increased to A Digital micromanometer for very low pressure measurement 61 22 mm of water head This model is the most economical when compared to all other models because mercury is totally avoided However pressure fluctuations are relatively more in this model and some special techniques have to be adopted in the manometer circuit to suppress such fluctuations In this model too air can be used as the experimental fluid instead of water Hence by making use of the conditions Y Y YW Y Y and as usual A A A A and A a in Eq 3 the following equation can be obtained for air as the experimental fluid for the third model AH AZ 1 3a A 1 y 6a 3 4 Fourth Model In this model the micro manometer is used as a piezometer to measure a single pressure P only instead of measuring a differential pressure heads like in the previous three models This model is useful only when the pressure head P y is relatively small In this model only the sumps
61. d self learning abilities of neural networks have been motivating factors for development of intelligent control systems The back propagation neural network based on the generalized delta learning rule a gradient descent search technique has been widely used Yabuta and Yamada proposed a neural control learning scheme where a neural network is trained to implement a non linear optimum regulator by minimizing a quadratic cost function Psaltis Sideris and Yamamura designed a neural network controller using MLP Narendra and Parthasarathi proposed an indirect inverse dynamics model learning approach The process control systems often exhibit some non linearity and variations in their parameters due to noise disturbances and other environmental factors making them difficult to control accurately In this paper two temperature control systems have been considered namely Water Bath Temperature Control System and Continually Stirred Tank Heater CSTH Neural Network Controllers NNC using MLPs are designed for both the systems and their performance is compared with the Conventional Feedback Controllers CFC with respect to set point regulation the effect of unknown load disturbance and variable dead time in the system ANN Controllers for Industrial Temperature Control Systems 49 This paper is organized as follows Section II includes a brief description of the water bath temperature control system and its CFC and NNC implementation
62. diabatic manner The relation between Static temperature the temperature when probe moves along at the velocity V of the flow and Total temperature is T Ts mn M2 The most important aerodynamic and thermodynamic factors affecting thermocouple design are 2 1 1 Velocity error In a probe the gas is not brought to rest adiabatically the velocity error caused by incomplete kinetic energy recovery is defined as 22 K Anil Kumar S A Vasudev and Meera Kaushal AT 1 r The velocity error can be minimised by decreasing Mach no MJ at the thermocouple junction by means of a stagnation tube 2 1 2 Conduction error The error caused by the heat conduction along the thermocouple wire is quantified as T T AT a 1 2 cosh L ox 2 1 3 Radiation error Radiation error is caused by radiation from thermocouple junction to the enclosure Wall O AT T 1 2 aT 2 2 Pressure measurement In a flowing gas the static pressure can be measured through a hole in a wall If the fluid is brought to rest by an isentropic process the pressure to a maximum value called Total pressure Total pressure Static pr Ps Dynamic pr p V 2 Fig 2 Probe Assembly Design and development of water cooled probes to measure pressure and temperature 23 Materty hia pg Es pap ovdi Der i 1 IFFT d E E a ERA a 1 FAT Oh if wee l i r LU IV ESH T aF
63. digital value FROM T C Fig 3 Circuit for temperature measurement 3 2 Temperature Measurement The signal generated by the thermocouple junction due to thermal changes is fed to an amplifier circuit is shown in figure 3 The output signal is amplified to a suitable level by using a instrumentation amplifier read by the microcontroller through AID Converter A semiconductor temperature sensor A0590 is used in the circuit to simulate a reference junction 102 A Rajendran and P Neelamegam MGC Ro OL Ti Ac Ro L P H 2 Be a os Da E N z Re ps Ra F1 Ra 13 3 Mee S 4i 10 i i 1 BD 138 RS i tid yew yi a GUEC EE NSE E HEATER RE Pe i A ge cal Cie Tn TO l Up ES a Pun Fig 4 Circuit for solid state power controller 3 3 Solid state power controller Figure 4 shows solid state power controller which is used to control the power to the heater The power controller is establishing a variable duty cycle switch with zero cross over switching The circuit is built around IC 555 timers triac driver MOC 3041 triac BD136 U7 wired as a variable duty cycle oscillator with a constant time period of around 0 1 second Duty cycle can be varied from 0 to 10096 using the resistance R1 to R7 which are selected by the multiplexer 4051 The duty cycle can be changed by proper words from the microcontroller to pin 9 10 and 11 of 4051 U8 wired as comparator with hys
64. dissipated in Zg2 From 19a and 22 V Vte V e Vgl 4Zg1 cos s 89 At centre frequency 6 II 2 and V2 jZ1 Vg1 8Zg1 Power dissipated in Zg assumed to be real P2 Z Vg 128 Zg Zg 20b 22a 22b 23 24a 4 way power divider cum combiner 69 Iz p zi a z3 Fra 1 er Anema zLmh a 22820 3 ud jp joue Vh Yu Var Ta Yu i I b Yin Fig 2 Power Divider iii Power output in the load ZO From 19 V and V can be obtained in terms of V and V Vt te I Z Z Z1Zg V 1 Z IZ Z Zg 25a Vx 2 2 V et 1 Z Z Z Zg V 1 Z Z Z Zg 25b Vez 2 2 Substituting in 20 a V V e cos j Z Zg Z sing V cosQ j Z Zg Z Z sin Q VS Zg Z V Z Zg 4Z Z 6 2 I2 Substituting for V1 and V1 from 22 V Vg Z Z Zg Zg 4 Z 8 26 Power in the load Z P Vg Z Z Zg Zg 4 Z 128 Z 27a Substituting for Z and Z from 13 and 14 into 24a and 27a Vg k k 3 27b P 64 Zg k 1 k 2 P Vg 32Zg k 1 24b And P P k k 3 2 k 2 28 As k takes values 1 2 3 P P becomes 0 66 1 25 and 1 8 i e the desired load power P can be increased relative to the isolated power P by increasing k For k unity P is less than P The transmission line characteristic admittances Y and Y can then be determined for a given value of k from 13 and
65. djusted to 8 so that the ADC will change its output by one LSB for 0 1 changes in pH at the sensor 5 DATA AND RESPECTIVE VALUE OF pH At the 7 pH the output of sensor is 0 000V hence the output of amplifier is OV and due to dual range working the data corresponding to 7 pH 0 00 V is 1000 0000 80 H Hence the microprocessor will read the value as 80 H As the maximum variation in the pH value is from 0 to 14 the ADC will give 70 different successive outputs above and bellow the value 80 H for total specified range of input So the total data corresponding to the specified values of pH will changes from 3A H to C6 H The corresponding data to the 0 pH 0 343 V 78 B T Jadhav Y S Shinde B B Godabale and S R Sawant output of follower and 2 744 V output of amplifier and the 14 pH 0 343 V o p of follower and 42 744 V o p of the amplifier are 3AH and C6H respectively Some data samples are shown in the Table II pH Hex data pH Hex data pH Hex data pH Hex data 0 3A 6 4 7A 7 1 81 8 8A 1 44 6 5 7B 7 2 82 9 94 2 4E 6 6 7C 7 3 83 10 9E 3 58 6 7 7D 7 4 84 11 A8 4 62 6 8 7E 7 5 85 12 B2 5 6C 6 9 7F 7 6 86 13 BC 6 76 7 80 7 8 87 14 C6 Table 2 Data samples 5 1 Conversion in real pH value The data corresponding to particular pH is available in the HEX form should be converted into the real pH value and displayed using the 8279 chip on the microprocessor display For this conver
66. dy Principal Prof I S Rao and Prof P R Naga Srinivasa of Department of Mechanical Engineering SNIST REFERENCES 1 E Fried and M J Kelley Thennal Conduction of Metallic Contacts in a Vacuum AIAA Paper No 65 661 AIAA Thennophysics Specialists Conference Monterey Ca USA Sept 1965 2 V A Mal kov and P A Dobashin The Effect of Soft Metal Coatings and Linings on Contact Thermal Resistance Inzhenemo Fizicheskii Zhurnal Vol 17 No 5 pp 871 879 1969 3 J Molgaard and Smeltzer The Thennal Contact Resistance at Gold Foil Surfaces Int J Heat Mass Transfer Vol 13 pp 1153 1161 1970 4 B B Mikic and G Carnaciali The Effect of Thennal Conductivity of Plating Material in Thennal Contact Resistance Trans ASME J of Heat Transfer Vol 92 No 3 pp 475 482 1970 5 L S Fletcher A Review of Thennal Control Materials for Metallic Junctions J of Spacecraft and Rockets Vol 9 pp 849 850 1972 6 L S Fletcher and T E Shoup Optimum Design of Elastomeric Gaskets for Combined Thermal and Vibration Perfonnance 1 of Spacecraft and Rockets V 01 11 No 5 p p 344 346 1974 7 T N Veziroglu H Yuneu and S Kakac Analysis of Thennal Conductance of Contacts with Interstitial Plates Int J Heat Mass Transfer Vol 19 pp 959 966 1976 8 PW O Callaghan S D Probert B Snait and F R Al Astrabadi Prediction of Interstitial filler Thickness for Minimum Thennal Contac
67. e CA 3080 OT A it is possible to achieve extremely linear transconductance characteristic with respect to amplifier bias current Readers who are interested in making active low pass filter can try out this design idea and discussions are cordially invited REFERENCES 1 10 11 12 13 14 15 16 Adel S Sedra amp Kenneth C Smith Microelectronic Circuits 4 Edition New Oxford Oxford University Press 1998 Vasudev K Aatre Network Theory amp Filter Design 2 Edition New Age International P Ltd 1980 Schaumann et Al Design of Analog Filters Passive Active RC and Switched Capacitor Prentice Hall Englewood Cliff New Jersy 1990 Louis Weinberg Network Analysis amp Synthesis McGraw Hill Book Company Inc 1962 S Franco Use of Transconductance Amplifier to make programmable active filters Electronic Design Vol 24 pp 98 101 Sep 1976 A M Soliman A Grounded Inductance Simulation Using the DVCCS DVCVS Proc IEEE Vol 66 pp 1089 1091 Sep 1978 H S Malvar Electronically Controlled Active Filters with Operational Transconductance Amplifier IEEE Tarns Circuits Syst Vol CAS 29 pp 333 336 May 1982 K Fukahori A Bipolar Voltage Controlled Tunable Filter IEEE J Solid State Circuits SC 16 pp 729 737 Dec 1981 V W Burgger B J Hosticka and G S Moschytz A Comparison of Semiconductor Controlled Sources for The Design of Active RC Imped
68. e can form dimers which are solids and lead to scale formation Hence frequent exposure to atmosphere during transfer is highly detrimental 2 3 Health hazard Exposure to TDI affects the respiratory system leading to irritation and breathing problem and in extreme cases requiring hospitalisation even for short exposure TDI is also carcinogenic in nature 3 GENERAL TRANSFER SYSTEM FOR HAZARDOUS CHEMICALS Two types of system are generally followed for transfer of hazardous liquid chemicals in the industry a Manual b Semi automatic In the manual system drums are tilted manually and material poured into a can for weighing Disadvantages of adopting this system are too many and high exposure is expected to persons handling the transfer as accurate weighing necessitates repeated handling Also tilting of drums is risky and involves inherent hazards In this method TDI exposed to moisture in the atmosphere forming dimers and affect the quality of TDI 30 Arvind Kumar K K Radhakrishnan and V K Bhat In semiautomatic system pedallistic stroke pump diaphragm pumps vertical pumps are used to transfer material from drum to measuring can In such a system pumps can be operated through control panel However because of pump discharge pressure such transfer involves more risk involving gland seal leakage from pumps Also another disadvantage is that pump has to be stopped manually and any error may cause disastrous consequences Besides t
69. e estimated conduction and radiation errors are 3 5 C and 12 5 C Generally two types of calibration need to be carried out for a stagnation temperature probe as per ASTM procedure 4 3 1 Normal temperature calibration A Cavity type black body is used to calibrate test Thermocouple of R Type Black body cavity is an isothermal cavity which emits radiation with an emissivity of approx 1 0 The cavity length is sufficient to accommodate the thermocouple enough to reduce the conduction error The test thermocouple is placed inside the cavity and setting of temperature is done with an accuracy of 5 C at 1000 c A multifunction calibrator MCX IT of M s Druck make is used to measure the signal of test thermocouple The values of temp and emf generated against standard value are given in Table 2 It shows the deviation between calibration value and standard value of R Type test thermocouple is within 0 8 2 387 0 58309 400 550 60 5 583 0 26867 650 8 157 6 157 0 00000 6 743 6 740 0 04449 0 00000 800 7 95 7 935 0 18868 Table 2 Comparison of standard output with actual thermocouple output for R Type Thermocouple 4 3 2 Recovery factor calibration The recovery factor of a stagnation temperature probe should always be known before using it for temperature measurement Probe calibration for temperature was not carried out but an experimental comparative study was carried out using an uncooled probe as refe
70. e of the other 3 arms looking outward from anyone arm at node 4 will be Yin 3Yin 1 The electrical lengths of the lines Zi Bi are assumed to be equal i e p BI B L 0 2 Therefore for lines of characteristic admittances Y Y and Y where Y 1 Z Y I Z and Y 1 Z we have Yg jY tano 4 AY Yin Yg Y Yg 0 II 2 3 i Y jYg tan0 Ys 4 Yin jY tan0 Yy Yin Y _________ Y Y ________ 9 1 2 4 YJ Yin tan Yin Yin jY tan xr Yin Y Y 8 7 2 5 Y Yin tanO Yin Now using 1 the admittances looking from the left are 3Yin j Y tano Y Yo Y Y Y Y ______ 9 9 2 6 Y 3 Yin tanO 3Yin Y t Y tano Y YY YE Yg t ________ 8 1 2 7 Y j Y tano Y 4 way power divider cum combiner 67 Y AVY tano X Ye MENU EMT 8 Y 1 j Y tano Y 3 CHARACTERISTIC ADMITTANCES OF TRANSMISSION LINES It is desirable that the antenna feeds the loads Z with as little power going into Zg as possible as shown in Fig 2 Hence the following requirements must be met i For matching between the antenna and Power Divider input Y n Yg 4 9 From 3 to 8 Y in is determined and equated to Yg1 4 This gives the following equation X410Y Yap Yan e2Y Y Yg V Ys Yo 10 ii This is also desirable that the power from the antenna arriving at port 2 is not ab sorbed in Zg Let Y n
71. ect to set point regulation The ability of the controllers to withstand load disturbance was also tested The last set of experiments was used to evaluate the performance of the two controllers with respect to variable dead time It is pertinent to add that neither the NNC was re trained nor the CFC was retuned for their performance comparison experiments z az gs m i f HES x LN d B ix ir gn ki di z zi F E I I ELI ined E n EH FT a Ed 1m DIES Tn amzlz dumb a b Fig 3 Disturbance Rejection Performance a CFC and b NNC for Water Bath System 52 A K Goel Manoj Kumar Sharma and Neeraj Gill 34 p L 31 B E Piu eme t g P 7 a Ez im a l 3 z a o 28 28 25 25 n a a a a 100 ta 10 D zu LU 5 m 100 1m 14 Sample Hunde e sampe Bunter a b Fig 4 Variable Time Delay Performance a CFC and b NNC for Water Bath System 4 1 Water Bath Temperature Control System The multi step reference tank temperature was given over 120 samples 30 C 40 C and 50 C for 40 samples each The tracking performance for CFC and NNC is shown in the fig 2a and 2b respectively For disturbance rejection test disturbances of 2 C and 2 C were added to the output at the 40th and 80th sampling instants resp The response of both the controllers is shown in the fig 3a and 3b respectively In the third set of experiments a delay of two samples was incorporated The response ob
72. ed in the late 30 s Thermal contact resistance plays an important role in aerospace electrical and electronic equipment when heat transfer from or to the equipment is very critical Earlier investigators observed that the thermal contact resistance conductance is influenced by 1 contact pressure 2 mean interface temperature 3 ambient pressure and temperature 4 interstitial material 5 heat flow direction 6 external magnetic field 7 vibration 8 surface roughness 9 waviness 10 thermal conductivity of the contacts and 11 micro hardness Each of these parameters will have its influence on thermal Development of a thermal contact conductance test facility 107 contact conductance It is due to this reason that the mathematical modeling of contact resistance problem is not fully successful and remains a research topic till today Therefore the designer of heat transfer equipment still depends on experimental results rather than the predicted values for a particular set of operating conditions for more reliability Keeping this in view several investigators developed test facilities to measure thermal contact conductance However each of these facilities that are developed in the past has their own advantages and limitations Hence to investigate the influence of each of these parameters on the thermal contact resistance a test facility is designed and developed which facilitates varying one parameter at a time keeping all other parameters consta
73. er 1 mm The wires are insulated by a layer of thin Teflon tape and are wrapped on the individual wires With all this the thermocouple junction measured 1 1 mm and tightly fits in to the drilled holes of 1 2 mm diameter in the heat flux meters and test specimens The total stretch of thermocouple wires from measuring junction to the cold junction is continuous and uninterrupted Fourteen thermocouples are used to measure the temperature in the test column and one thermocouple to measure the reference bath temperature Thermocouple extension cables are used to connect the cold junctions to the measuring instrument The cold junction of the thermocouple is maintained at O C using a reference bath that contains melting ice in Development of a thermal contact conductance test facility 111 distilled water The reference bath is capable of maintaining the temperature with in 0 05 C The output from the temperature sensors is read through a precession multimeter The output e m f is converted into the corresponding temperature using the calibration curve of the thermocouples The temperature measurement accuracy of the system is I C 9 EXPERIMENTAL PROCEDURE To start the experiment the heat flux meters and the test specimens are installed in the test column in accordance with the arrangement shown in the Fig 2 The holes that are meant for installing the thermocouples are filled with silicon heat sink compound with a syringe and thermocouples are in
74. er deals with the design and development of wireless data acquisition system for meteorological variables Two variables namely solar intensity and wind speed are measured and their outputs are conditioned The Remote Data Acquisition System is designed using a micro controller and its output is fed to the FSK modulator A cordless circuit is used to transmit and receive the modulated signal The received signal is demodulated and fed to the Pc The values are displayed in a user friendly format The designed system is tested in the laboratory for a range of 100m I INTRODUCTION 1 1 Meteorology Meteorology is the science of the earth s atmosphere and its changes used especially in forecasting the weather Continuous monitoring of atmospheric parameters is an essential aspect for this Wind speed and wind direction are measured using a wind anemograph or cup anemometer Solar intensity or Sunshine is measured by concentrating the beam of sunlight by a convex lens on to a strip with markings on it Due to the heat the strip turns brownish and the level of brownish area based on markings can be related to solar intensity From the meteorological instruments the readings are taken manually processed and then sent to the Central Meteorological Center by the meteorological observer Usually readings are taken at the interval of 3 hrs which make up to 8 observations a day 1 2 Wireless Data Acquisition System To overcome the difficulty of measur
75. er of fig 11 Here V SL R 18 and V IR 19 Solution of equation 18 and equation 19 gives us transfer function R L T s 20 Fig 11 First order passive low pass filter second method 1 7 8 Prasant K Mahapatra Manjeet Singh and Neelesh Kumar Realization using OTAs From fig 12 it can be inferred that V IJSC 21 L mn 7 V Em 22 Var Yd Em Solving equation 21 and 22 we have V 23 SG L E 24 I Vau 25 But we see that L 4 I 0 26 Solution of equations 24 25 and 26 gives the transfer function of the designed filter a S ni m2 C E RR EM E 27 Fig 12 First order active low pass filter second method 5 CONCLUSIONS The above discussion concludes that we can achieve a tunable range of cut off frequency And for low pass filter we can change cut off frequency by changing only one parameter g The advantage of using first method can be summarized as follows 1 Number of OTA used is only one 2 We can change cut off frequency by changing gm but the degree of freedom for changing g is only one Realization of Active filters using Operational Transconductance Amplifier OTA 9 In case of second method cut off frequency can be changed by tuning or g separately or in combination So we have a larger tunable than the first one A number of different OTAs are available in market from various manufacturers With the use th
76. es of resistors amp inductors as calculated from mathematical expression which mayor may not be available in the market To solve this problem we can use OT As We achieve the required resistance and inductance values by varying its gm What follows describes the use of OTAs as basic building blocks I 2 in the design of low pass active filters Electric filter 1 3 can be defined as a frequency selective electrical circuit that passes electrical signals of specified band of frequencies and attenuates gt the signals of frequencies outside the band Passive components are generally the basic building blocks of filters which work normally on high frequencies but at audio frequencies inductor causes problem Inductor size increases at audio frequency and become bulky amp expensive At low frequencies inductor requires more number of turns which adds series resistances and degrades inductor s performance because of its low quality factor Q which results in high power dissipation Using OTA the above mentioned problems are solved For Low pass filter 1 the general first order transfer function can be written as 2 Prasant K Mahapatra Manjeet Singh and Neelesh Kumar HoWo T s S Qo Where Ho DC gain 6 resonant frequency or cutoff frequency The current section has described the fundamental problems in general filter design the second section gives the general description of OT A third section describes the basi
77. estigated Heat flow through the contact can be measured over a wide range of contact pressures 0 1 to 40MPa and mean interface temperatures 0 to 250 C The associated thermal potential differences required for calculation of thermal contact resistance can be measured The use and the reliability of this apparatus are established by the measurements made on nominally flat contacts of 88 304 An additional and more important feature is that the direction of heat flow can be reversed without disturbing the contact under investigation The apparatus also facilitates measurement of thermal conductivity Using this test facility Thermal contact conductance across 88 304 test specimens is measured with and with out copper foils as interstitial materials in the contact pressure range of 0 1 to 2 MPa The results showed that in the presence of copper metallic foils the contact conductance increased rapidly with increase in contact pressure when compared to the bare joint under the same set of conditions The results are presented in graphical form 1 INTRODUCTION When two solid surfaces are brought in contact with each other for the purpose of transmitting energy in the form of heat or electricity the interface formed between them is known as contact When conduction heat transfer takes place across the interface an extra resistance known as thermal contact resistance exists at the interface The importance of thermal contact conductance has been recognis
78. eters of 63mm and 28 mm respectively Therefore a A 0 1975 and from Eq 7 C 16 09 A plot between the display reading of the manometer and the head All measured by a traveling microscope is shown in Fig 3 The data points fall on a linear line with a slope of 16 83 suggests that the manometer is working very well as per the principle However theory suggests C 16 09 where as from calibration it is obtained as 16 83 thus there is a variation in the manometer constant Such a variation is generally expected and it is attributed mainly due to functioning of the capacitive transducer it self Also it is due to some variations in unit weights of liquids and variation in the sump diameters as well as their verticality which 62 Achanta Ramakrishna Rao can affect directly the value of a A Thus the micromanometer is working very well and serving the purpose of low pressure measurements 8 M BB ee o Eg i H 05 10 15 20 Manometer Display reading rnm 50 00 Fig 3 Calibration of Micromanometer 5 RESULTS A digital micromanometer for low differential pressure heads is developed as shown schematically in Fig 1 It contains three major components namely 1 manometer circuit it is conveniently designed to use either water or air as experimental fluid 2 a capacitive transducer the main innovations in this component are either to make use of i mercury meniscus as a moving p
79. f Fig 2a Temperature Probe Fig 2b Combination Probe 3 PROBE DESIGN The variety of physical and aerodynamic conditions of gas flowing through the test section needs close attention while deciding the geometric design of probe Two types of Water cooled probes were designed as shown in Fig 2a viz Temperature rake which measure Total temperature and Fig 2b viz Combination probe which measure Total pressure and Total temperature both The probe stem was made with Nickel based super alloy The required water flow rate for cooling the entire probe when subjected to maximum operating condition is estimated as 2 5 Itrs min and the actual flow measured is in safer side Though the probe was first made with Nickel based super alloy the usage of low cost SS material is also possible as sufficient water flows through the probe to maintain its properties The aerodynamic shape allows the probe to eliminate the wake effect to a great extent The SS tubes are used inside the probe to route thermocouple as well as pressure line out of the probe stem The wall thickness between the water and gas side in the probe was crucial because of space constraint in the probe But in actual use water pressure is maintained equal to gas pressure during all rig operating conditions thus maintaining the structural integrity of the probe During the testing of probes one of the main areas of concern was temperature measurement The hot junction of t
80. f 0 00 Imm for a range up to 2mm 3 MODELS OF MICROMANOMETERS It may be appropriate to mention here that lesser the value of C then the measurement accuracy of AH is higher however the range of AH is reduced the reverse is also true such that the range of AH can be increased by increasing the value of C however the accuracy of AH measurement decreases Above Eq 3 is the general or governing equation of the micro manometer as shown in Fig l and such an equation can be used to develop several models of micro manometers with different values of CM with certain relative technical and economic advantages Four of such models are discussed here under the common conditions of A A A A A a a A 0 1 and AZ is measured with an accuracy of 0 001 mm and its range is up to 2mm 3 1 First Model In this model mercury is used as manometric liquid in all the sumps thus Yor Ym Y the unit weight of mercury Also the cross sectional areas of the sumps S S and S are equal to A i e A A A A where as the sump S containing the probe M is of a relatively smaller cross sectional area A a The unit weight of air in sump S and S at their top is Ya In this model both water and air can be used as experimental or working fluid If water is taken as the experimental fluid then y y unit weight of water and a governing equation for this model can be deduced from Eq 3 as AH AZ l a A y Y Y 2a A Y Y D 4 The u
81. f Continually Stirred Tank Heater with ANNs using Successive Over Relaxation Back propagation Algorithm Asian Control Conference ASCC 2002 Singapore 614 617 2002 7 Ogata K Modem Control Systems Third Edition Prentice Hall Englewood Cliffs New Jersey 1998 8 A K Goel and Surekha Bhanot Successive Overrelaxation Back Propagation Algorithm for ANN Training A Simulation Study Int Conf on Computer Applications in Electrical Engg IIT Rorkee 245 249 2002 J Instrum Soc India 35 1 54 64 A DIGITAL MICROMANOMETER FOR VERY LOW PRESSURE MEASUREMENT Achanta Ramakrishna Rao Dept of Civil Engg Indian Institute of Science Bangalore 560 012 ABSTRACT A highly sensitive micromanometer to measure low differential pressure heads is developed It works on capacitance principle by which it measures the air gap up to 2mm with an accuracy of 0 001 mm between either a mercury meniscus or a metallic float and a sensing element with an accuracy of 0 001 mm The movement of mercury meniscus or a metallic float is due to the applied differential pressure in the manometer circuit It has a digital display and can be connected to a computer through a data acquisition system for continuous recording of data It can be used either for water or air as experimental fluids Also it is easy to operate and maintain as well as reasonably very economical too and ideally suited for Indian conditions It has applications in hydr
82. f the microprocessor Sr No pH indicated by std Meter pH indicated by this system 1 7 01 7 0 2 4 96 5 0 3 8 55 8 4 4 10 15 10 0 5 11 00 10 9 Table IV Sample results REFERENCES 1 N U Nayak R H Suresh Bapu Nalini Tondiraj and Y Mahadev Iyer PC CONTROLLED ON LINE pH MEASUREMENT AND CONTROL SYSTEM USING INDIGENOUS pH TRANSMITTER 1 Instrument Society of India 31 2 p 150 154 Yadagiri P Thyagarajan T Panda R C Rao P G Advances in modeling and analysis B Signals Information s Patterns Data acquisition Transmission Processing Classification 43 3 p 41 63 Gopal M Kumar S et al Synthesis of a robust pH controller using QFT Proceedings of IEEE TENCON 1998 IEEE USA p 214 217 Vol 1 M N Aoutade Improved techniques for measurement of ph unit 5 Ph D Thesis submitted to Pune University p 99 114 National semiconductor Data manual P 7 105 D Patranabis Principles of Industrial Instrumentation Tata McGraw Hill Publishing Company Limited p 475 481 B Ram Microprocessor PHI Publishing Company Limited New Delhi J Instrum Soc India 35 1 84 89 DESIGN AND IMPLEMENTATION OF REMOTE DATA ACQUISITION SYSTEM FOR METEOROLOGY S Meenatchisundaram S Dwaragha Arumugham and K Venugopal Department of Instrumentation and Control Engineering Regional Engineering College Tiruchirappalli Tamilnadu ABSTRACT This pap
83. for all state orders up to the maximum 12 is computed The optimal order k is the order for which AIC is minimum which is the order of the true simulation model Modeling of middle product of a distillation column using akaike information criteria 95 Alom top pressure Ea Top temp Top reflux N phtra flaw rule Kerosene siripping rate Diesel Craw raie Crude from vrude healers i To vacuum heaters oo um healers Fig 2 Process flow diagram Atmosphere tower The AIC is calculated 5 using the expression as given in eq 5 AIC k 2log p Y UN 0 2M 5 where p is the lag and M is the number of parameters in the state space model given by M k 2n m mn n n 1 2 6 Here k is the number of states n the number of outputs and m is the number of inputs to the system 6 The optimal state order is used to compute the state space model of the form 96 A Vimala Juliet and S Renganathan X 6X GU W 7 and the output eg is given by Y HX AU BW V 8 where X is the Markov state order W and V are white noise processes that are independent with covariance matrices Q and R G H A and B are coefficient matrices and their optimal estimates are found by CVA procedure 7 4 RESULTS AND DISCUSSION In the present work we have taken the middle product temperature of the distillation column as the control variable The middle product is accurately maintained
84. ge of phase in either the tank fluid or the jacket fluid The volume of water in the tank and the jacket is assumed to be constant Therefore the inlet and outlet flow rates are same The tank and the jacket inlet temperatures are equal to 10 C and 90 C respectively The objective is to attain the output tank temperature at 50 C The two equations for this system are obtained as dor p ie dt V p C Teen Ga TE dt V V pt where T and Tj are tank and jacket temperatures F and Fj are tank and jacket flow rates Ti and Tji are the tank and jacket inlet temperatures U is the overall heat transfer coefficient and A is the area for heat transfer C and C are the tank and the jacket heat capacities p and p are the tank and jacket fluid density Y and Yj are the tank and jacket volumes and t is time For this system cascade control scheme as shown in fig I is used In the control scheme two PI controllers are used in cascade The primary controller is used to set the reference point Tj for the secondary controller The objective of the secondary controller is to attain the set Tj by manipulating Fj in the range 0 to 60 It min The cascade control scheme was implemented in MATLAB and SIMULINK The sampling time of 6 sec was used in the simulation The transfer functions used were obtained by linearizing the equations 2 amp 3 The primary and secondary controllers were tuned by hit and trial method The gain parameters for the two
85. ght y in sumps S and S have to under go a similar change such that it lowers by AZ and rises by AZ in the respective sumps By assuming all the manometric fluids including air are incompressible the volumetric displacement in each of the sumps is the same hence the following expression is valid A AZ A AZ AAZ A AZ a constant 2 Where A A A and are the cross sectional areas of the sumps S S S and S respectively The following general expression or governing equation can be derived for the differential pressure head AH in terms of water while balancing the pressures at various levels in the manometer circuit AH AZ y YANASA DOn DP ECALZA Y a YNNN AAD Qr WY 3 Where y is the unit weight of water One may prefer to express the differential pressure head AH in terms of mercury then unit weight of mercury Ym has to be used in place of y The value of terms inside the square brackets is called as the manometer constant C and hence Eq 3 can be expressed as follows AH C AZ 3a A Digital micromanometer for very low pressure measurement 59 The probe M measures the air gap AR between the mercury meniscus and itself as shown in Fig 1 It may be noted that as AR reduces there is an increase in AZ and vice versa and thus there exists a direct relation between AZ and AR Therefore one may say that the capacitive transducer measures indirectly the relative changes in AZ with an accuracy o
86. given as output The irradiation or the solar intensity is equal to the ratio of the output of pyranometer in uV and the sensitivity of the pyranometer in mV W m The sensitivity of the pyranometer used is 5 11 yV W m The resistance variation with intensity of light for a full 24 hr day are measured A data logger is used to record the pyranometer output and resistance of LDR Each value of pyranometer output in mY recorded for a day is converted into solar intensity A chart is drawn showing the Input Output characteristic of the chosen LDR with the help of recorded readings as shown in figure 2 LOR resistancetohm 500 0 500 1000 1500 2000 2500 Solar intensity Wa m Fig 2 Input output characteristics of LDR 86 S Meenatchisundaram S Dwaragha Arumugham and K Venugopal 2 2 Atmospheric Wind Speed Sensor An alternator with rotating blades on its rotor is chosen as a sensor as in the figure 3 The output of the transducer is 0 12 V ac m Line P gt LLLA Atmospheric 4 1 e f nnd t Nx ELE THU l Neutral N Res uis cafe e a Side View b Front View Fig 3 Layout of the atmospheric wind speed sensor By placing a hot wire anemometer 3 near the chosen transducer the Input Output characteristics are determined as shown in figure 4 MON Peak ta peak eutputoftne wind treed m senseri m Atmespharie yuna p aed m s
87. hermocouple is surrounded by cooled walls of probe stem and exposed to gas through an opening It was not possible to provide a Kiel type sensor because of space constraint The error observed during the test was 50 to 70 C as radiation and conduction losses were too much Later a metallic shield was incorporated surrounding 24 K Anil Kumar S A Vasudev and Meera Kaushal the hot junction and that helped to reduce the error But the use of metallic shield is restricted as there is a chance of melting Finally a radiation shield made out of cemented carbide was used The thermocouple can be inserted into the probe as a replaceable unit Provisions are made to bleed the air through tube to ambient with high velocity which increases the coefficient of convective heat transfer but up to a level of the maximum allowable velocity error The loss because of conduction and radiation can be minimised by having high velocity through stagnation tube 4 CALIBRATION AND ERROR ESTIMATION 4 1 Pressure measurement Probes are fabricated and assembled after undergoing various manufacturing process brazing and welding So precision in the pressure measurement depends on the final geometrical dimensions of probe In order to achieve the precision in pressure measurement the probe was calibrated against a master probe Pressure calibration is carried out in calibration facility GTRE A master probe Wedge shaped supplied by M s Rotodata was used as reference
88. his contamination due to moisture and consequent formation of impurities will be the same as in case of manual transfer 4 DESIGN APPROACH In the present design remotely operated PLC Programmable Logic Controller based SCADA Supervisory Control amp Data Acquisition system is incorporated with safety interlocks and logics for transferring TDI with a weighing accuracy of 10 gm in 5 kg The design and the logics added to the system overrule any accidental spillage and subsequent environmental pollution and thus take care of human safety In the present transfer system set point only has to be entered on control screen and if all the safety interlocks are checked and found okay then only transfer of material will start and automatically stop at desired set point Consequently accuracy and repeatability is expected to be of high order The transfer mechanism is a combination of vacuum and gravity flow and as such risk and hazards involved will be reduced to a large extent Because of PLC amp SCADA all the necessary safety interlock and effective control can be given in this type of transfer system Along with these aspects contamination due to moisture will also be negligible as exposure to atmospheric moisture is minimized 4 1 Design description The selection of instruments and interlocks in the present design is to ensure accurate weighing of clear liquid TDI received from trade in drums without any normal impurities as detailed in
89. his instrument the conductivity of KCL solution at various temperatures is measured and it is shown in figure 6 p a E 5 3 3 s o 40 50 60 70 80 0 Temperature deg cen Fig 6 Conductivity of Kcl solution at various temperatures REFERENCES 1 J R Engstrom and W H Weinberg Design and construction of a digital temperature controller for use in surface studies Rev Sci Instrum Yo1 55 pp 404 1984 2 J E Maclennan M R Meadows M A Handschy and N A Clark Persollal computer based programmable temperature controller for general laboratory applications Rev Sci Instrum vol 56 pp 775 1985 3 P Neelamegam K Padmanabhan and S Selvasekarapandian Automated Thermoluminescence measurements using 6502 microcomputer board Meas Sci Technol 3 1992 pp 581 587 J Instrum Soc India 35 1 106 113 DEVELOPMENT OF A THERMAL CONTACT CONDUCTANCE TEST FACILITY V Vasudeva Rao R Raghukulender and M V Krishna Murthy Department of Mechanical Engineering Sreenidhi Institute of Science and Technology Hyderabad 501 301 Department of Mechanical Engineering Indian Institute of Science Bangalore 560 012 ABSTRACT This paper presents the details of a test facility developed to measure thermal contact resistance across metallic contacts The construction and instrumentation is such that contacts of various geometry nominally flat hemisphere to flat cone to flat contacts can be inv
90. hydraulic leakages and periodic weightings as per above discussions Graphical Programming Applications to Data Acquisition 19 The setting pressure of C30 chock shield was 300 bars at 8 29 hrs on 27 March 2003 as shown in Figure 10 The support was advanced at 15 00 16 13 and 19 31 hrs The support pressure was increased to 400 bars at 21 00 hrs due to onset of periodic weighting The support pressure was reduced to 250 bars at 21 44 hrs due to face hydraulic leakage The support was in the centre of the panel The RT system was successfully recorded chock shield C30 behavior as per above discussions 5 CONCLUSIONS Software menus were successfully developed on LabVIEW programming environment and incorporated in the RT system for user friendly operations The graphical programming environment was successfully explored for developing compatible software menus to mining applications with password id protection In Indian mines security of the systems and software is very important due to most expensive mining systems and machinery In addition the productivity and safety of mining operations are also very important Therefore compatible software with required security was successfully developed and implemented The RT system was successfully recorded and forecasted various failures of mining machinery and adverse strata behavior as per real time analysis to effective mining operations First time the RT system was successfully developed indigeno
91. iation of less than I Volt This resulted in a constant heat generation and thereby a stable temperature of the heater cooler block Analog Watt meter connected in series indicates the power dissipated in the heater 7 COOLING CIRCUIT A closed loop cooling circuit consisting of a constant temperature bath a centrifugal pump cooling coils embedded in the heater cooler blocks is used The temperature of the heater cooler block can be varied in the range of 195 C to 150 C and maintained with in 1 C by choosing an appropriate coolant When the temperatures are to be varied between 30 C to 0 c ethylene glycol may be replaced for distilled water and Methyl cyclohexane may be replaced to reach 85 C Liquid Nitrogen may be used as a coolant to go down to 195 C LN can be circulated in the coils by pressurising the LN dewar with compressed Nitrogen and can be let out to the atmosphere after it boils off 8 INSTRUMENTATION The basic measurements involved in contact conductance and thermal conductivity tests are temperature measurements The instrumentation in the present test facility consists of temperature sensors T Type thermocouples constant temperature reference bath and a precession multimeter SWG 24 gauge thermocouple wire is drawn from a single spool and cut to required lengths The measuring junctions of the thermocouples are formed by fme soldering The beads so formed are shining bright and their diameter measured slightly ov
92. ical Variate Analysis and Akaike Information Criteria has been performed to determine State variables State transitions have been obtained by computing the nonlinear regression The Canonical variate analysis has been used to determine the state of a distillation column directly from the data without making any assumptions about the functional form of the nonlinear dynamics Akaike Information Criteria has been used to find an appropriate model order Thus the Canonical Variate Analysis has yielded satisfactory results when state space form of the model proposed by Larimore has been used REFERENCES 1 Peter Eserin et al Application of CVA to the Dynamical Modeling amp Control of Drum level in an Boiler Proc ACC 1999 p1163 2 Charles D Schaper et al Identification of Chemical Processes using Canonical Variate Analysis Proc 29th Conference on Decision and Control Hawaii Dec 1990 p605 3 Akaike H A New look at Statistical model identification IEEE Trans Auto Con Dec vol 19 6 1974 p716 4 Wallace E Larimore Automated multi variable system Identification Short Course University of California Santa Barbara p1 5 Dale E Seborg et al Identification of the Tennesse Eastman challenge process with subspace methods p106 6 Wallace E Larimore Identification of co linear and co integrated multi variable system using canonical variate analysis IFAC SYSID 1999 Santa Barbara Jun 2000 pl
93. ing ICs 8255 PPI and 8279 respectively 4 CALIBRATION ADC converts the analog data to the digital equivalent and is stored in the memory in the hex form but user can t estimate correct value of pH accurately So it is required to convert this data into its equivalent value of pH that is understandable to the user directly without any need of conversion The calibration is done with the help of proper software programming in such a way that it will represent the equivalent pH directly and display it 7 4 1 Logic for gain adjustment of the amplifier The ADC is used in the dual range we can apply any voltage between 5V to 5V and the total voltage accepted by it is 10 V in magnitude The ADC has 8 bit resolution so it makes the 2 8 i e 256 different output combinations hence it makes 255 parts of the 10V The voltage corresponding to single part is 10 V 255 0 0392 V As we need the accuracy of 0 1 in pH the output of the follower changes by 0 049 V for change of 1 pH at the sensor hence for 0 1 variations in the pH value the follower output will changes by 0 0049 V Hence the output of amplifier changes by value A 0 0049 V where A is the gain of the amplifier The ADC will be able to differentiate this change in the voltage if it is equal to the voltage required for changing its output by one LSB Mathematically Gain A 0 0049 0 03921 A 0 03921 0 0049 A 8 003 A 8 To have proper calibration the gain of amplifier is a
94. ing the meteorological variables manually a wireless data acquisition system is designed and implemented as shown in figure 1 Two variables namely solar intensity and atmospheric wind speed are chosen as variables The Solar Intensity and Wind speed are measured using Solar Intensity Sensor LDR and Wind Speed Sensor Alternator respectively The measured signals are fed to the micro controller then transmitted and received using FSK modulation Design and implementation of remote data acquisition system for meteorology 85 FSE Modulation HE Ds play m To Computer Cordless Cordless FSK De TTL i au o lassression Reception Modulaticn R5 Bae Part L i C mversicn 1 Fig l Block diagram of the wireless data acquisition system 2 SENSORS 2 1 Solar Intensity Sensor LDR is used as the sensor Its input output characteristics are determined with the help of a pyranometer Pyranometer has the thermal detector which responds to the total power absorbed and theoretically it is non selective to the spectral distribution of radiation This implies that the naked thermal detector is also sensitive to long wave IR radiation from environment The radiation energy is absorbed by a black painted disk present in it The heat generated flows through a thermal resistance to the heat sink the pyranometer body The temperature difference across the thermal resistance of the disk is converted to a voltage and
95. its using microprocessor micro controllers and personal computers Some instruments cannot prescribe correct value of pH and also there are variations in the readings 1 We design and develop a simple laboratory purpose microprocessor based pH measuring system 2 MEASURING TECHNIQUE The Fig 1 Shows the complete block diagram of microprocessor based pH measuring System The buffer solution having pH values 0 to 14 is used for testing and calibration purpose in practice it may be any chemical The combined electrode consists of pH glass and reference electrode in a single entity converts the H ion concentration into the corresponding voltage The isolator cum follower circuit follows the mV output from the sensor the MOS FET IC CA 3140 acts as a follower The mV output is amplified and temperature compensated using the inverting stage of the OP AMP IC 741 and signal is set at desired value To convert analog signal in to the digital ADC form IC 0809 is used and IC LF 398 74 B T Jadhav Y S Shinde B B Godabale and S R Sawant Buffer pit Isolator Solution Sensor Follower Microprocessor ADC System Fig l Block diagram of microprocessor based pH measuring System Amplifier Gain and temp compensation Sample and hold Tue Ke peo lerkth pyp Fig 2 Circuit Diagram provides the sample and hold facility By utilizing the one of the port of IC 8255 the microprocessor 8085 collects the pH values
96. ity of the NNC over the CFC figure 4 and 7 ANN Controllers for Industrial Temperature Control Systems 53 5 CONCLUSION Two control systems for temperature regulations of Water Bath and Continually Stirred Tank Heater CSTH have been implemented The CFC scheme is found to be simple to implement but performs poorly with respect to set point regulation disturbance rejection and variable time delays Neural Network based controller performed far better and therefore it is concluded that they offer a large scope in further advancement in the field of intelligent instrumentation ACKNOWLEDGEMENT This work was supported by the grant from AICTE Govt of India for the TAPTEC project TAP 325 REFERENCES 1 White D A and D A Sofge Handbook of intelligent control Van Nostrand Reinhold New York 1992 2 T Yabuta and T Yamata Learning control using neural networks proc 1991 IEEE Int Conf Robotics Automation Sacramento CA 1991 3 D Psaltis A Sideris and A Yamamura A multilayered neural network controller IEEE control Syst Mag 10 no 3 44 48 1989 4 K S Narendra and K Parthasarathy Identification and control of dynamical systems using neural networks IEEE Trans Neural Networks 1 4 27 1990 5 Sigeru Omatu Marzuki Khalid and Rubiyah Yusof Neuro Control and its Applications Springer Verlag London Limited 1996 6 A K Goel and Surekha Bhanot Modeling o
97. l becomes smooth amp robust The main advantage of fuzzy pH control is that it doesn t required detailed mathematical model of pH controlling process to make stability The results are good amp it is expected to be better than those of conventional control method 3 Rules fires IF pH is SP THEN LFPVO IS SD with DoM 0 3 IF pH is PM THEN LFPVO is NM with DoM 0 7 4 Defuzzified LFPVO LFPVO 14 3 mm 5 The New pH attained 7 13 Table 3 Sample results Modulated pH ae O CO N ID Nn A wN Table 4 pH modulation through Iteration Optinivation of pH value through iteration T4 Y 1 a h 2 61 E M EON m9 5 6 8 a7 L ee x Q 2 4 amp 8 10 No of ltcratiau Fig 4 Optimization of pH value through Iteration Fuzzy logic pH controller in sugar industry 47 REFERENCES L 10 11 12 13 14 15 E Hugot Handbook of Cane Sugar Engineering 1972 Elsevier Publishing Company New York ch 25 pp 407 408 P Honing Principles of Sugar Technology 1953 Volume I 2 Elsevier Publishing Company New York L Foullay S Galichet Fuzzy Sensors For Fuzzy Control Vol 2 No 1 1994 55 66 Editorial Staff Developments in process control and instrumentation in sugar in dustry INT SUGAR JNL 2000 Vol 102 No 1222 M Benn B Grondin Perez J D Lan Sun Luk and J P Chabriat Modelling Cane Sugar va
98. l policy 2 2 2 Rule Base The control policy of pH control is formulated in terms of fuzzy inference rules 9 4 3 These rules are either gathered from experienced buman operator or careful study of existing pH control systems The rule base thus represents the control strategy employed in the pH control Typical set of rules is given in the Table II User can modify the rule base to suit well to his control policy M pH is NL THEN LFPVO is PL pH is N THEN LEPVO is P pH is MM THEN LTPVO i PM pH is SP THEN LEPVO is SD pli is PM THEN LFPVO is MM pl ow P THEN LEPVO is NM pH is PH THEN LFPVO is NH ee m Table 2 Set of Fuzzy action rules The incoming pH value from sensor fires the rules from rule base system then enter into the fuzzy inference process 2 2 3 Inference Engine The inference scheme employed in pH control is based on individual rule firing of Mamadani type In this scheme contribution of each rule is evaluated and overall decision is derived 101 During inference process each rule is individually fired by a crisp value of pH coming from sensor and fuzzification module determines degrees of satisfaction of rules This generates clipped fuzzy sets CFS representing opening of the valve for lime flow The process of inference is illustrated in Fig 3 Fuzzy logic pH controller in sugar industry 45 2 2 4 Defuzzification Defuzzification of clipped fuzzy sets generated in the fuzzy
99. l system using PID algorithm is shown in figure 5 C start Initialize System Sampler Mea tem Find crror signal Measured temp set point Cooling Process gt rs Error signal Perform PID algorithm i Output control value via multiplexer Update error signal 3 Fig 5a Flowchart for temperature measurement and control using PID algorithm 104 A Rajendran and P Neelamegam Create proportional part Kp X ej nT ei nT e n 1 Tx T e nT ei n 1 T T 2 Prepare set value x T Set Value x T T ei nT ei n 1 T X Ki 2 Ka T ei nT ei n 1 T Fig 5b Flowchart for temperature measurement and control using PID algorithm 5 RESULTS AND DISCUSSION During the development stages the various circuit units of the hardware system were evaluated individually and as an integrated unit All the software systems were enhanced to achieve optimum operation In addition for different samples the experiment was run under different environments in the completely automated mode to illustrate the capabilities of the system The instrument was tested by measuring temperatures in a wide range 30 to 500 C Design of AT89C52 microcontroller based system for the measurement of temperature and control 105 The performance of the instrument is compared with the electrx digital temperature controller to check accuracy of the instrument Using t
100. l words check the data received HEX LOOP ADDRESS I Read the 6FDA Start 6FDC 6FDE 6FEO 6FE2 6FE4 DO 6FE5 6FE8 6FEA 6FEC 6FEE 6FFO 6FF2 6FFA 6FF6 DI 6FF7 6FFA 6FFC 6FFE 7000 7001 7003 7005 Loop 7006 7009 700B 700D EOC 700F 7010 7013 7015 7017 7019 D2 701A 701D 701F 7022 7024 7026 Microprocessor Based pH Measuring System 79 Table 3 Assembly Language program MNEMONICS Data from the MVI OUT MVI OUT 09 MVI DCR JNZ OUT DCR JNZ OUT MVI Nap OUT MVI DCR JNZ OUT IN JNC OUT DCR JNZ IN STA OUT A 98 OB 1 02 D3 09 D 03 D DO 1 00 09 A 03 OA A 04 09 C FF C A 00 09 A OB OA C FF C Loop 1 03 OA OA A 08 09 C FF 08 2800 A 00 2800 OP CODE ADC using 3E 98 D3 OB 3E 02 16 03 15 C2 E4 6F 3E 00 D3 09 3E 03 D3 OA 3E 04 D3 09 OE FF OD C2 F6 6F 3E 00 D3 09 3E OB 00 D3 0A OE FF OD C2 05 70 3E 03 D3 OA DB OA 17 D2 OD 70 3E 08 D3 09 OE FF OD C2 19 70 DB 08 32 00 28 3E 00 D3 09 3A 00 28 COMMENTS Sample amp Hold Control word Send logic high Adjust delay for logic Make logic low Select channel 3 ALE high Delay ALE low Send SOC high Delay Send SOC low Check EOC Send OE high Delay Read data and store at 2800 H Make OE low 80 NEXT DEC D3 Sendin CONT B T Jadhav Y S Shinde B B
101. late in capacitance circuit in some models 1 2 and 4 models or ii a metallic float as a moving plate in some other models 3rd model with a view to measure accurately and display digitally the air gap AR between the fixed plate probe M and the movable plate either mercury meniscus or metallic float which moves because of the applied differential pressure head AH and 3 a general equation governing the working principle as given in Eq 3 connecting the functioning of components 1 and 2 Several types of micro manometers can be designed from Eq 3 however for sake of illustration some models are discussed and presented in Table 1 by assuming the following conditions A A A A A a and AR 0 1 and AR indirectly the AZ is measured by the capacitance circuit with an accuracy of 0 00lmm and its range is up to 2mm 6 CONCLUSIONS A micro manometer which works on capacitance principle is developed and presented It has a direct digital display with a provision to monitor continuous monitoring of data It can be used to measure differential pressures with either air or water as the experimental fluids Four different models of micromanometer are presented for use under different conditions along with their economy for a real use The working principle of the manometer is verified by conducting a calibration study A Digital micromanometer for very low pressure measurement 63 The manometric mE
102. lender and M V Krishna Murthy Bare Joint Foil Joint Linear Foil Joint Linear BareJoint Thermal Joint Conductance KW sq m K 0 1 2 3 4 5 6 7 8 9 10 1l Applied Presure P MPa Fig 3 Improvement in Thermal Joint Conductance due to Al foil as Thermal Control Material Bare Joint 6 49um Foil Joint 6 51 um A Bare Joint a Foil Joint Linear Foil Joint Thermal Joint Conductance hj kW sq m K Linear Bare Joint Applied Pressure P MPa Fig 4 Improvement in Thermal Joint Conductance due to A1 foil as Thermal Control Material Bare Joint 9 49um Foil Joint 9 51 um Effect of Al Metallic foils on Thermal Contact Conductance across Contacts of Stainless Steel 304 119 je 4 b 3 o Bare Joint Foil Joint Linear Bare Joint Linear Foil Joint Thermal Joint Conductance hj kW Sq m K 1 2 3 4 3 6 7 8 9 10 1 Applied Pressure P MPa Fig 5 Improvement in Thermal Joint Conductance due to A1 foil as Thermal Control Material Bare Joint 12 42 um Foil Joint 13 4 um oS 1 2 microns cO o C D 6 73 microns 9 49 microns 12 42 microns Linear kW sq m K I 0 A CO Thermal Contact Conductance he 0 2 4 8 8 10 12 Applied Pressure P MPa Fig 6 Comparison of Contact Conductance Vs Applied Pressure for Bare Joints 120 V Vasudeva Rao A Kumara Swamy R Raghukulender and M V Krishna Murthy 15 13 4 microns 9 5 microns in
103. ler and AT89C52 microcontroller A two row 16 characters LCD display from Hitachi is interfaced with microcontroller to allow user communications and to display the results 100 A Rajendran and P Neelamegam Thermocouple Instrumentation 12 bit A D amplifier Converter Solid State Power AT89C52 Controller Microcontroller Fig 1 Block diagram of temperature measurement and control 3 HARDWARE SYSTEM 3 1 A T89C52 Microcontroller and A D converter Figure 2 shows AT89C52 microcontroller and 12 bit A D converter IC7109 The AT89C52 microcontroller is a low power high performance CMOS 8 bit microcontroller with 8 KB of flash programmable and erasable memory and 256 bytes of RAM It has 16 bit timer counters a full duplex serial port on chip oscillator clock circuitry and low power idle and power down modes and it has the facility of three level program memory lock Port 0 of the microcontroller is interfaced with 12 bit A D converter IC 7109 The 7109 A D converter is a high performance low power integrating device which provides the used with high accuracy low noise low drift versatile and economical A D converter of the dual slope ZCLID STATE VEC Ud ME OF POWER CONTROLLER MOC er 2 zl FAAP Pa ga REF OUT 4 i5 PO 1 Ler xL Pa Pa 3 REF IN ie PO 4 x2 Pols L_ f PO C B REF IN Pa aol RESET BS REF CAP ni P2 a Pos PZ SEER 3 INTO PELE BIR REF
104. low rate is adjusted by varying the airflow to the compressor using the potentiometer and stepper motor auto arrangement Here also two pH sensors are used Such controller is used in Jawahar Sugar Ltd Hupari Kolhapur M S For lime flow variation valve is adjusted using stepper motor Whatever may be the way of control the pH the target is get the clear juice To embed the practical knowledge of human operator in the conventional controller to control the pH we propose fuzzy logic based pH controller by keeping the raw juice and SO gas flow rates constant and controlling the lime flow by varying the valve opening diameter mm The variations of pH values with respect to the lime flow valve opening diameter LFVOD mm are given in the Table 1 Table 1 pH Variation with lime flow 2 DEVELOPMENT OF FUZZY LOGIC PH CONTROL SYSTEM The complete set up of fuzzy logic based pH control system is shown in Fig 1 The combined glass pH electrode is calibrated with the ELICO based pH meter This electrode is pH Sensor Signal Conditioning i h pH Indicator ABC FUZZY CONTROL MODULE FICATION FUZI INFERENCE ENGINE DEFUZZIFICATION Knowledge Base DA amp Stepper motor drive I Fig l Block diagram of Fuzzy pH Control system in 42 B T Jadhav G G Tengshe A B Kulkarni R R Mudholkar and S R Sawant easily available in the market The I
105. lve with actual run of TDI The effectiveness of filter was also tested by deliberate inclusion of solid dimer in TDI liquid The weighed out material was found to be clear TDI liquid with 10gm accuracy 7 CONCLUSIONS The transfer and weighing system designed is incorporating the control logic with safety interlocks for transfer and weighing of hazardous liquid like Toluene diisocyanate and is found useful in reducing the health hazards associated with such chemicals The scheme can be adapted to other similar liquid transfer systems where in automatic control on accuracy and non exposure is required REFERENCES 1 G Weirs Hazardous Chemical data book second edition 2 Ullmann Ullmann s Encyclopedia of Industrial Chemistry 3 DJ Davis J A Davis G T Cristianson Fire Fighter s Hazardous material 2nd edition 4 Jeffrey W Vincoli Risk seal valves for hazardous chemicals 5 Rajesh Salins Bellow seal valves for hazardous applications J Chemical Industry Digest Pumps amp Valves Special Issue 77 1993 Vinod C Bhasin Actuator Selection J Chemical Engineering 140 Nov 1990 7 S Ram Mohan Valves Actuator Sizing and Selection J Chemical Industry Digest Pumps amp Valves Special Issue 81 1993 8 Christopher Read Start to Improve Batch Operations J Chemical ENgineering Progress 69 Jan 2000 9 Joseph La Fauci Choose the Right Control System J Chemi
106. ly in the form of voltage pulses of 5 10 volts In case where the code is intended to be transmitted over long distances it is available as potential free contacts to be converted into voltage pulses at the other end National Physical Laboratory New Delhi is transmitting Indian Standard Time via INSAT satellite The users of this time service usually have a commercial master clock which can get synchronized by IRIG B time code For this purpose we have designed the receiving system of the satellite based time service so as to provide the time in IRIG B format Other users who do not have such a master clock would like to get the correct time of NPL displayed remotely For this it is necessary to decode the IRIG B time code and to display it The present design is in that context 2 IRIG B FORMAT The format of IRIG B serial time code is shown in fig 1 Each frame of IRIG B is of one second duration and comprises a pulses at intervals of 10 ms a total of 100 pulses These pulses are either 2 ms or 5 ms or 8 ms wide representing a logical 0 or 1 or a Design of Decoder for IRIG B Time Code 35 OO 1Qigi1 ia o 1 acici1oo0 pj 11109 10 0 of 10 o 1icj00 0 a 4 ii s ii X 7 iib oa g rr g seconds 34 minutes 12 hours 17 days 1 09 2 ms 4 3 715 01001500 2 0 _ 4 2 ii a ll 1 bit days 100 02 8 ms Position marker Fig 1 IRIG B Time Code Format l A1 A8 B1 B amp
107. make and maintain A highly sensitive tilting gauge capable of reading 2 5x10 cm of water called Chattock tilting gauge was in use and it was later modified by Duncan 1927 Ower and Pankhurst 1966 and Pankhurst and Holder 1968 Other types of sensitive manometers with zero adjustment of the indicator were developed by various investigators They generally consist of a reservoir with a plunger an inclined sight tube and a vernier arrangement A manometer developed by Hodgson 1929 with such an arrangement was found to be ten times more accurate than the Chattock gauge Later Macmillan 1954 and Smith amp Murphy 1955 also developed similar manometers with certain improvements The manometer showed an accuracy of 2 x 10 inch 0 005 mm of water for differential pressures of less than 0 8 inch 20 mm of water Stalhane 1934 developed yet another null type manometer using two different sized horizontally kept cylindrical vessels containing alcohol The smaller vessel contains an air bubble which is like an air bubble in spirit level which is used as an indicator This manometer was designed for field use and it has an accuracy of 0 01 mm of water Some others used flexible bellows in the manometer whose sensitivity was comparable to the Chattock gauge While reviewing the various types of sensitive micro manometers one may come to a conclusion that they still have certain limitations A major limitation in a null type manometer is its
108. mean interface temperature and direction of heat flow 10 SYSTEM RESPONSE The output from the developed system is in the form of temperature data The input to the system is in the form of externally controlled parameters In the present context the system response basically means that how the system responds in the form of a change in the contact conductance output for a known change in the externally controlled parameters input To show the system response typical experimental data are presented in which one parameter namely contact pressure is varied keeping all the other parameters constant 10 a System Response for a Change in Contact Pressure Fig 3 shows the variation of thermal contact conductance in the test column when the contact pressure load on the test column is increased in steps as and when the system attained steady state conditions according to a pre set condition The object of the experiment is to determine the effect of contact pressure on thermal contact conductance at constant electrical power 64W input to the top heater in atmospheric environment of atm pressure In this experiment top heating with bottom cooling configuration is used The experiments were also conducted to determine the effect of 100um thickness copper foil on thermal contact conductance when compared to bare joints under the same test conditions 112 V Vasudeva Rao R Raghukulender and M V Krishna Murthy Stainless Steel 304 test speci
109. mens used in the present investigation are with RMS surface roughness of 2 56um for the top specimen and 1 01um for the bottom specimen The results indicate that the thermal contact conductance for the bare joint is higher than the contact conductance of the joint with copper foil of 100J 1m thickness as interstitial material for a given set of conditions This undesirable trend is due to the dominating bulk thermal resistance offered by the thick copper foil than the plastic flow of deformed foil to fill the voids and reduce Thermal Contact Resistance With this it is predicted that the enhancement in the contact conductance takes place with the foil of lesser thickness that conforms to the surface texture of the contacting surfaces with the application of pressure gs o Bare Joint om o A FoilJoint Linear Foil Joint A Linear Bare Joint p o Pd e N E 7 p or o Thermal Contact Conductance hc kW sq m K e E 0 0 0 5 1 0 i 2 0 Applied Pressure P MPa Fig 3 Comparison of Thermal Contact Conductance Vs Applied Pressure for Bare and Foil Joint 11 CONCLUSIONS The developed test facility to measure thermal contact conductance across metal metal contacts is proven to be effective in terms of measured thermal conductivity of the specimens The maximum error in the measured value of thermal conductivity is found to be 6 86 and a minimum of 0 78 when compare to the ASM metals
110. mitting antenna and radio modem The pressure and leg closure ireless receiving antenna Real Time System Intelligent dump terminal Surface monitoring system Data acquisition system Wireless transmitting antenna Abounded exploration bore hole Tower Over ground Surface reddidi Under ground Under ground ultipair double armored data cable Underground pressure and leg closure from leg closure and pressure sensors sensors interfaced to chock shields Fig 5 Instrumentation layout of over and underground 16 Srinivasulu Tadisetty Kikuo Matsui and R N Gupta sensors interfaced to the surface data acquisition system Figure 5 The output of data acquisition system was interfaced to radio modem The output of radio modem interfaced to the wireless transmitter as shown in Figure5 The surface monitoring system Figure 6 was mainly comprises of radio modem with wireless receiver RT system and intelligent dump terminal The wireless receiver was received data from wireless transmitter The RT system was received data from wireless radio modem The RT system was executed in built data analysis software routines The result of the analysis was sent to intelligent dump terminal Intelligent dump terminal has in built display This display also called as a real time display Therefore the received data was displayed on real time display as shown in Figure 6 5 3 Real Time Sy
111. nal Boston Ch 3 7 9 pp 45 469 T Terano K Asai and M Sugeno Applied Fuzzy Systems 1997 AP Professional London chap 1 pp 1 7 ch 2 3 pp 26 49 51 56 J Instrum Soc India 35 1 48 53 ANN CONTROLLERS FOR INDUSTRIAL TEMPERATURE CONTROL SYSTEMS A K Goel Manoj Kumar Sharma and Neeraj Gill GZS College of Engg amp Tech Bathinda 151 001 ABSTRACT Temperature control systems play an important role in the process industry In this paper Artificial Neural Network ANN controllers using multilayer perceptrons MLPs are designed for a simple water bath system and a Continually Stirred Tank Heater Their performance is compared with the conventional feedback controllers CFC with respect to set point regulation the effect of unknown disturbances and variable time delay in the systems On comparison the performance of neural network controller NNC is found better in tracking the reference than the CFC From simulation results it is concluded that the NNC outperform the CFC and offer a large scope in further advancement in the field of intelligent instrumentation I INTRODUCTION The conventional feedback controllers find wide applications in the process industry as they can be implemented very easily However to compensate for plant parameter variations and set point changes etc such fixed gain feedback controllers are insufficient and need to be retuned The massive parallel processing nonlinear mapping an
112. nd Probert S D Can Standards Be Set for Reliable Measurements of Thermal Contact Conductance AIAA 83 0533 AIAA 21st Aerospace Science Meeting January 10 13 Reno Nevada 1983 J Instrum Soc India 35 1 114 121 EFFECT OF Al METALLIC FOILS ON THERMAL CONTACT CONDUCTANCE ACROSS CONTACTS OF STAINLESS STEEL 304 V Vasudeva Rao A Kumara Swamy R Raghukulender and M V Krishna Murthy Department of Mechanical Engineering Sreenidhi Institute of Science and Technology Hyderabad 501 301 Department of Mechanical Engineering Indian Institute of Science Bangalore 560 012 ABSTRACT This paper presents the results of an experimental investigation conducted to determine the effect of Aluminium metallic foils on the thermal contact conductance between nominally flat contacts of 88 304 The contacting surfaces of the steel specimens are generated by turning on a precision lathe and then characterized for surface parameters using a Taly Surf surface roughness tester A set of 8 pairs of specimens is included in the present investigation A set of 4 pairs is tested with Aluminium foils of thickness 20um and another set of 4 pairs is tested without a foil In the present work 56 data points are obtained and results are reported in graphical form Experiments are conducted to determine Thermal Contact Conductance in the pressure range of 0 1 to 10 MPa The results of the present investigation revealed that the enhancement of contac
113. ne In this design remotely operated PLC based SCADA system is incorporated with safety interlocks and logics for transferring TDI with a weighing accuracy of 10g in 5 kg The design and the logics added to the system overrule any accidental spillage and subsequent environmental pollution and thus take care of human safety The total scheme uses various electronic field instruments Selection of instruments and their application has been done in such a way that operation of TDI transfer and weighing becomes more accurate and safe to environment This can be used for any similar application where hazardous chemicals are to be transferred 1 INTRODUCTION In the field of defence and space the new class of heterogeneous solid composite propellant has come to stay for application in large size boosters and also in small tactical missile propulsion requirements This class of propellant is heterogeneous in nature and consist of inorganic oxidisers and metallic fuel embedded in a polymeric binder matrix The matrix which provides the required structural rigidity to the solid propellant is generally polyurethane formed by cross linking of telechelic polymer and an isocyanate Toluene diisocyanate TDI is widely used in the industry all over the globe as the isocyanate not only for propellant Design of a TDI transfer and weighing system 29 manufacturing but also in most of the polyurethane industries TDI is reported to cause health hazards even a
114. nt ftom the capacitor The capacitor has no any leakage current so that its voltage remains constant and followed at olp of slh circuit until the logic is low Afterward when logic is high capacitor charges to the new value and same process followed to have constant output 3 5 Analog to Digital Converter ADC As the analog data cannot be processed or handled and stored using microprocessor which can handle the large data with very high processing speed it is required to converts into digital equivalent form This is done with the monolithic package IC 0809 using successive approximation technique It has 8 bit data bus and is connected to the one of the port of the 8255 The data can be stored and processed using up 8085 and the proper software The ADC 0809 is provided with additional circuit at its input stage to have its working in bipolar rage of input voltage The Clock applied to ADC may vary from 10KHz to 1 2 MHz For clock ftequency of 640 KHz the conversion time is 100 microseconds and the error of conversion is 1 LSB Care should be taken that the Ve reference voltage should not exceed the Vcc and Ve reference should not be less than the Vcc or ground Out of eight input channels input is accepted from one amp is selected by sending the proper address of the channel followed by address latch signal The start of conversion SOC pulse is sent to start the conversion and end of conversion EOC pulse is checked If EOC is recei
115. nt throughout the experiment irrespective of the other operating conditions 2 LITERATURE REVIEW Fletcher and Madhusudana and Fletcher 2 presented excellent reviews on the developments in contact heat transfer its importance and applications in various fields Fletcher presented various experimental techniques for thermal contact resistance measurements and test facilities developed by different investigators O Callaghan and Probert suggested certain specific modifications to take care of transverse losses in the test column O Callaghan and Probert developed an improved test facility by duly incorporating the suggestions of O Callaghan and Probert Snaith et al discussed several difficulties associated when accurate measurements of thermal contact conductance are to be made The accuracy of measurement depends on specimen geometry form ratio transverse heat losses the apparatus design heat metering temperature measurement and measurement procedures The authors recommended a number of special criteria for thermal contact conductance testing and analysis However there has been little serious consideration or implementation of these recommendations The apparatus design which is the most important one among all the above mentioned factors can suffice all the other requirements From the published literature it is known that there are no test facilities designed duly implementing the recommendations of Snaith et al Precisely it is
116. nterstitial materials to improve thermal joint conductance is known for the last two decades Due to the limitations associated with the mathematical predictions experimental results are very much required when the role of contact conductance is very critical 2 LITERATURE SURVEY There are several theoretical and experimental investigations that involve the determination of the effect of interstitial materials on Thermal contact conductance TCC Some of the most important contributions in this area have been presented here to give the current state of the art Fried and Kelley investigated the influence of aluminium vapour deposited coating on the Thermal Conduction of Metallic Contacts in a Vacuum environment Mal kov and Dobashin considered soft sliver coating on SS contacts for enhancement of contact conductance in vacuum Molgaard and Smeltzer presented the results of Thermal Contact Resistance of Gold Foil Surfaces in the range of 30 to 500 C Mikic and Carnaciali studied the Effect of Thermal Conductivity of Plating Material in Thermal Contact Resistance and validated the solutions with experimental results Fletcher presented a Review of Thermal Control Materials for Metallic Junctions and introduced concept of non dimensional conductance for thermal joints with interstitial materials Fletcher and Shoup proposed Optimum Design of Elastomeric Gaskets for Combined Thermal and Vibration Performance in a view to reduce both vibration tr
117. oltage operated device which will not draw any current from the sensor and hence loading of sensor is avoided The only remedy for this is use of isolated gate FET or MOS FET IC which acts as a follower 3 As it was required to follow the sensor output it is needed to use amplifier with unit gain so we use the easily available MOS FET IC CA 3140 that is pin compatible to the normal OP AMP The IC CA 3140 have very high input impedance about 1 5 Tera ohm and bias current is also very low about 1 Pico Ampere hence it avoids any loading on sensor Practically CA 3140 has better current driving capacity and acts as an insulator at the input stage its speed of operation is also very high because of the FET S used in it A follower is used in the non inverting mode so its gain is 1 Rf Ri which approximately equals to the unity because the input resistance Ri is very high as compare to Rf The offset null is achieved by feeding the appropriate voltage at the inverting terminal Thus this stage so follow the same voltage that is fed to it by the pH sensor 3 3 Amplifier The output from follower stage is fed to inverting amplifier IC 741 and its gain is adjusted by varying feedback resistor for proper calibration The OP AMP IC 741 has very wide bandwidth and starts from zero frequency The gain of inverting amplifier is Rf Ri and is adjusted by varying the 100K ohm potentiometer connected in series with the 10K resistor that is same as input resi
118. onally the parameter estimation requires nonlinear iterative parameter optimization that encounters convergence problems especially for multi variable systems The Canonical Variate Analysis provides an alternative method for finding state space or equivalent ARMAX models using a computation ally efficient and stable algorithm Once model of this process is developed then the refined model selection can be determined using Akaike Information Criteria In Section 2 we discuss the working of the Distillation Column The State space model along with Canonical Variate Analysis is briefly discussed in Sections 3 Modeling of middle product of a distillation column using akaike information criteria 91 2 PROCESS DESCRIPTION The physical separation of mixtures can be achieved by various methods like filters extraction etc But Distillation Column method is most suitable in Petrochemical industries It separates based on the volatility of the components present in the crude oil The Distillation tower at Chennai Petroleum Corporation Ltd Tamil Nadu India is 40 3m tall vertical column with 4 5m diameter in the fractionating section The detailed model of the distillation column dynamics is not available Data for the present work collected from the open loop response of the column is shown in Table and graphically shown in Figs a j The ten Manipulated Variables and five Control Variables and their ranges are shown in Tables 2 and 3 The fra
119. onversion process Port C 7 is checked for EOC The digital data is received through port A and stored in register RI 4 2 Transmission Programming The data that is received and stored in register R1 of micro controller is sent out serially though the on chip serial ports at a baud rate of 1200 8051 has a serial data communication circuit that uses register SBUF to hold data Register SCON controls data communication register and baud rate is determined by the mode chosen and by initializing the timer with required count for baud rate Typically timer 1 is used in timer mode 2 as an auto load 8 bit timer Transmission of serial data bits begins anytime data is written to SBUF The flag TI in SCON is set to a 1 when the data has been transmitted and signifies that SBUF is empty So the program waits for the TI flag before transmitting next data Each data byte is sent with a frame that has 2 start bytes channel number corresponding to the data byte and data byte 88 S Meenatchisundaram S Dwaragha Arumugham and K Venugopal T Fig 6 Signal Conditioning for Wind Speed Sensor A delay of 6 5ms is included between the transmissions of 2 individual bytes The output of serial ports is given to the FSK modulator after passing through a RS232C TTL level converter 5 COMMUNICATION CIRCUITS 5 1 FSK MODEM The Frequency Shifting Keying FSK is employed in modulation demodulation of digital information using an XR2206 and XR2211 res
120. ot always be pure and may slowly contaminate the whole manometric system Also these manometers are either too rigid or too delicate to facilitate day today operation and maintenance It is therefore essential to have a manometer which is highly sensitive simple in operation and maintenance and easy in fabrication Keeping these in view a high sensitive liquid bubble manometer for measuring low differential heads primarily intended for use in open channel flow has been developed by Rao 1979 It can also be seen in reference Rao and Vedula 1981 It has a built in calibration facility and can be used to measure differential pressure heads up to a maximum of 20 mm with an accuracy of 0 0 1 mm of water The liquid bubble consists of two miscible liquids viz benzaldehyde and normal hexane each of which is immiscible in water in such a proportion that the bubble density is very close to that of water density The liquid bubble which occupies the full cross sectional area of the glass tube containing the water traverses in a glass tube in proportion to the differential pressure applied This too has the following minor limitations The density of the liquid bubble must be carefully maintained within 2 of the density of water and the liquid bubble has to be frequently replaced Water in the manometer should be chemically clean The major advantage of this manometer is its cost and accuracy in measurement It hardly costs few hundred Indian rupees
121. ould not be very well established in India Longwall powered supports leg pressure changes as a function of time and distance with longwall face advancement A loading peak intensity is related to the occurrence of severe roof movement when a crack is propagating in the main roof A strong and thick overhang corresponds to a large overhang and high loading peak by the time the overhang reaches its maximum length Most of the longwall mines contain multiple layers in the main roof resulting in a complex loading history due to the combined effect of individual layer The variation of loading history over a considerable period of time Graphical Programming Applications to Data Acquisition 11 and inhibits the analysis for trends and correlations with loading events It is rather difficult to interpret the monitored data using traditional conventional data analysis techniques but recent technological development in the area of instrumentation provides a great opportunity to solve complex problems Microcomputers have made it practical to install a high speed acquisition to collect data from longwall face in near real time Jiang et al 1996 This paper will highlight the innovative LabVIEW menus which were incorporated in the RT system for better user interface 2 GRAPHICAL PROGRAMMING ENVIRONMENT LabVIEW Laboratory Virtual Instrument Engineering Workbench is a graphical programming environment that uses icons instead of lines of text to create a
122. paper a 4 way Power Divider cum Combiner has been analyzed which uses transmission lines instead of resistors connected between the output ports The lengths of the lines are taken to be A 4 at the centre frequency The Power Divider is assumed to be matched at the input port Also the power fed into the divider is assumed to be split in the ratio k l between the coupled and isolated ports With these assumptions the expressions for coupled power and power into the isolated port are derived The corresponding expressions are like ise derived for the Power Combiner 66 A K Agrawal The structure of Power Divider cum Combiner is shown in Fig t In the Power Divider the power from the antenna represented by source Vg with internal impedance Zg is distributed into four 50 ohm loads In the Power Combiner the powers from four sources Vg with internal impedances Zg are combined and fed into the antenna at port 1 In the latter case the ports with 50 ohm loads are the isolated ports 2 THE POWER DIVIDER For convenience and due to symmetry only one arm of the 4 way Power Divider need be considered as shown in Fig 2 The assumed input admittances looking from either side at the four nodes are also shown in the figure The antenna admittance in each arm will then become Yg 4 where Yg 1 Zg Similarly the admittance of sources Vg is Yg l Zg Let Yin be the admittance looking leftward into any arm from node 4 Then the total input admittanc
123. pectively In this technique the logic 0 and 1 are transmitted using two different frequencies 2200Hz and 1200Hz called preset carrier frequencies The signal that is sent out serially from the micro controller is taken to the FSK modulator via the RS232 C Interface The signal amplitude is converted from RS232 to TTL level using MC1489 5 2 Cordless Transmitter and Receiver FM transmitter of handset of cordless phone is used to transmit the FSK signal and the base is used to receive the FM signal To perform the operation the following modifications are made in the cordless phone Dialing section is removed bypassed in both base and handset so that the cordless phone operates as if it were an intercom Design and implementation of remote data acquisition system for meteorology 89 Telephone line interface is disconnected Power to handset is supplied with direct variable voltage source and battery is removed Mike in handset is removed and FSK signal is given to the nodes The output signal is given as input to the FSK Demodulator instead of giving it to speaker and the speaker is removed The FSK demodulated signal and the ground signal are connected to the 2nd and 5th pin of the pin connector of the RS 232C interface of the computer A code in C language is written to display the measurement values in the computer The code first initializes the baud rate number of bits per character number of stop bits 6 CONCLUSIONS The Remo
124. poration and Crystallisation J of Indian Sugar June 2000 pp 141 146 G Eggleeston Hot and Cold lime clarification in raw sugar manufacture II Lime addition and settling behaviour INT SUGARJNL 2000 VOL 102 NO 122 G J Klir and B Yuan Fuzzy Sets and Fuzzy Logic 1997 Prentice Hall of India New Delhi Ch 1 12 pp 1 29 327 339 D Driankov H Hellendoom and M Reinfrank An Introduction to Fuzzy Control 1996 Narosa Publishing House New Delhi Ch I 3 pp 1 144 K Tanaka Translated by T Tiimira An Introduction to Fuzzy Logic for Practical Applications 1996 Springer Verlag New York Ch 1 4 5 pp 1 13 81 86 121 130 R R Yager amp D P Pilev Essentials of Fuzzy Modeling and Control 1994 A Wiley Interscience Publications New York ch 4 pp 109 148 Parvati C S amp Prahlad V Fuzzy Controller For A Separately Excited DC Motor 1993 Proceedings of National Science Conference IIT Kanpur India pp 202 207 K C Cheok K Kobayashi S Scaccia and G Scaccia 1996 A Fuzzy Logic Based Smart Automatic Windshield Wiper IEEE Control Systems pp 28 33 R R Mudholkar S R Sawant G G Tengshe and AB Bagwan Fuzzy Logic Transformer Design Algorithm FLTDA 1999 Active and Passive Elec Comp Overseas Publishers Association N V Vol 22 pp 17 29 E Cox The Fuzzy Systems Handbook A Practitioners Guide to building using and maintaining Fuzzy Systems 1998 AP Professio
125. pplications In contrast to text based programming languages where instructions determine program execution LabVIEW is a program development environment much like modern C or Basic development environment It is a general purpose programming system with extensive libraries of functions for any programming task LabVIEW gives the flexibility and performance of a powerful programming language without the associated difficulty and complexity It can reduce system development and increase productivity LabVIEW programs are called virtual instruments or VIs virtual instruments because their appearance and operation imitate physical instruments VIs are hierarchical and modular It can be used to top level programming or subprograms within other programs The VI comprises the following three components Front panel The front panel is the user interface of the VI and has controls and indicators which are interactive input and output terminals of the VI respectively Controls are knobs pushbuttons dials and other input devices and supply data to the block diagram of the VI Indicators will simulate instrument output devices and display data Block diagram After building the front panel add code using graphical representations of functions to control the front panel objects The block diagram is contains this graphical source code Front panel objects appear as terminals on the block diagram Additionally the block diagram comprises of functions and str
126. pports in standard format for easy and quick access The data continuity and reliability was maintained due to in built reliable wireless operations Graphical Programming Applications to Data Acquisition 17 Wiehe meek Beal dae badiy Hed tese sysdem iria miamba Conon infir ion Wm ae Img agora chap ierni SETTE ee ETI Fig 6 Real Time System interfaced to Wireless Receiver and intelligent dump terminal 5 4 REAL TIME ANALYSIS AND INTERPRETATION OF FIELD DATA The real time data analysis and interpretation of selected data records of RT system are as follows Chock shield C64 setting pressure was 250 bars initially at 20 23 hrs on 26 April 2002 as shown in Figure 7 The chock shield pressure increased in steps to 278 bars from 20 23 to 22 53 hrs due to face operations The support pressure reduced to 262 bars at 23 00 hrs due to fall in the goal The chock shield was near the tailgate The RT system was successfully recorded and forewarned the adverse shield behavior for implementing necessary precautionary measures during fall in the goal at 23 00 hrs The RT system was successfully recorded the behavior of C64 chock shield as discussed above Support behaviour of C64 on 27 04 2002 375 370 365 360 355 350 345 340 335 330 325 320 r T T T r r r r r T T r r r r 1 20 02 21 17 22 32 23 47 Elapsed time hh mm Ressueinkas Fig 7 Chock shields C64 behavior on 26 April 2002 18 Srinivasulu Tadiset
127. process yields the single crisp value of Lime Flow Pipe Valve Opening mm that represents the overall fuzzy outcome Many defuzzification methods are available however Height Defuzzification HD being computationally simple and fast is employed here 5 _ The crisp rate of lime flow pipe valve opening is given by equation 7 q Y Pm h r 1 LFPVO mm e Y hh r 1 Where P peak value of r clipped fuzzy set h height of r clipped fuzzy set and q number of fuzzy rules fired The process of HD is shown is illustrated in Fig 3 Defuzzified value of LFPVO works to keep the pH value of sugar juice to a target value SP PM rq m DoM 0 7 DoM 03 l ns 691 710 747 721 pH Membership functions pH for p A pH 7 15 MN IF pis SP THEN LFPD is SD RULES si IF pH is PM THEN EFPD is NM p apen mm NM 8D DoS 0 7 h Po 0 0 p 13 i4 15 16 17 Membership functions Lime Flow Valve3Opening mm Fig 3 Inference Process and Defuzzification 46 B T Jadhav G G Tengshe A B Kulkarni R R Mudholkar and S R Sawant 3 SAMPLE RESULTS Sample results are highlighted in Table III The modulation of pH value adjusted by pipe valve opening diameter carrying the lime juice is shown in the Table IV followed by graphical variation of pH in the Fig 4 The loop of pH variation continuous till pH reaches to set value hence the contro
128. programming of configuration menu Otherwise he will not be allowed to modify or program the system operations Therefore the RT system operations were fully protected from unauthorized operations Thus the system operations are reliable and accurate 5 APPLICATION OF REAL TIME SYSTEM 5 1 Experimental mine The problematic longwall mine was selected at Ramagundem area II The longwall panel No 4 was prepared in one seam bottom section leaving the 3m clay shale coal in the roof at GDK Godavarikhani 10A SCCL Singareni Collieries Company Limited Ramagundem Depth of the panel varies from 247 to 297m The compressive strength of the stone roof is 13 6 MPa The overlying strata was highly water bearing Longwall retreat was 4 to 5 m per day An average daily production was 2000 t The panel and face length were of 940 and 116 m respectively The panel working height was 3 0 m This panel was equipped with 80 chock shields of capacity 4X800 t The seam thickness was 6 40 m with a 0 30 m clay band and an average gradient of 1 in 6 towards N73 E The strata overlying in the coal seam was composed of coarse to medium grained ferruginous sandstone coarse grained kaolinised felspathic massive sandstone with clay and gray shale s 5 2 Instrumentation Layout Figure 5 shows instrumentation layout of over and under ground All the systems and modules were controlled by RT system The wireless data acquisition system was mainly comprises of wireless trans
129. rence An Air preheater increases the temperature of compressed air to 555 C and pass through a long duct to settle the temperature uniform and allows passing through a test section where test and uncooled probes are fitted Temperature of gas is controlled within 2 C using a microprocessor based Moore controller A PLC Programmable logic controller based data acquisition system used to acquire the data in every 500 millisec The system is capable to process the data at a scan rate of 50 samples sec The experiment result is given in Table 3 Design and development of water cooled probes to measure pressure and temperature 27 Uncooled probe Temp Hub Pee ce 3 Point Temperature Test probe Mean Deviation Deg e B De o To Deviation ER 0 540541 553 0 36036 0 0 71 9424 x 0 179856 0 540541 555 Q 0 540541 554 0 18018 Cloe e 0 540541 e sss sss 0 3e03e_ eea osaoser s2 0 540541 0 38036 0 540541 Table 3 Comparison of water cooled probe readings with uncooled probe readings 5 RESULTS AND DISCUSSIONS The pressure probe calibration was carried out from 0 33 to 0 672 Mach numbers Total 9 readings were taken and duration of each reading was approximately 60 mins The probe has shown the error within 1 5 of the dynamic head The temperature probe checking was carried at 0 15 Mach number The gas flow
130. respectively The sumps S and S as well as S and S are connected at their bottom where as the sumps S and S are connected at the top as shown in Fig 1 The sumps S and S and the sumps S and S are filled with heavier liquids A Digital micromanometer for very low pressure measurement 57 Sump S4 S3 S3 S4 area A A 83 Aa not drawn to scale Fig l Schematic Diagram of Micromanometer of unit weights y and Y respectively Air of unit weight y is trapped on the top of the sumps S and S Let the levels of manometric fluids stand at a datum of 0 0 before the application of differential pressure as shown in Fig 1 The cocks C C and C can be used appropriately to induct sufficient quantities of manometric fluids and to apply differential pressures as well as to remove any air bubbles in the experimental fluids The sump S is connected with a higher pressure P where as the sump S is connected with a lower pressure of P Thus the applied differential pressure head is AH HH P P y 1 Where y is the unit weight of the experimental fluid The micromanometer is expected to measure and display the differential pressure head AH with highest possible accuracy A probe M which measures the air gap AR between the mercury meniscus and itself is rigidly fixed at the top of the sump S such that there is free communication of pressure through air in the sumps S and S However sufficient gap i
131. rface are smeared with a thin layer of silicon heat sink compound to reduce the thermal resistance at these interfaces to a minimum value Then the ball and conical seating are kept in position along with the loading pin three radiation shields as shown in the Fig 1 This completes the assembly of the test column c Experimental Procedure The test column is instrumented with calibrated thermocouples of T type The out put of the thermocouples via a zero degrees centigrade reference bath is measured using a precision multi meter The loading of the test column is achieved by a lever and static hanging weights Heating and cooling circuits are switched ON to set a temperature gradient Temperature measurements are taken after the test column attaining the steady state conditions The experiment is continued in a similar way after increasing the load to a next higher value 4 RESULTS AND DISCUSSION The results of the present experimental investigation are presented graphically in fig 2 through fig 7 Fig 2 shows the results of a thermal joint that has a surface roughness Foil Jom Bare Joint Linear Foil Joint Thermal Joint Conductance hj kW sq m K Linear Bare Joint D 1 2 3 4 5 6 7 8 9 l H Applied Pressure P MPa Fig 2 Improvement in Thermal Joint Conductance due to A1 foil as Thermal Control Material Bare Joint 1 20um Foil Joint 1 28 um 118 V Vasudeva Rao A Kumara Swamy R Raghuku
132. s developed in this system are simple to use and provide versatility in programming temperature ranges and timing processes 1 INTRODUCTION The measurement of temperature is important in medicine ecology industry and plant science research Accurate measurements are required with close attention to the sensitivity of the instrument used over the whole measured range in order to achieve reliable results Conventionally these measurements were performed byvarying the temperature manually in steps are recorded either manually or on the chart The main aim of this paper is to describe a data acquisition system for measurement of temperature and control the system based on a microcontroller that has been designed and developed using PID algorithm Electronic temperature controllers are commercially available and some of them have been reported in literature 1 2 The continuous and tedious attention required for manual adjustment is eliminated Typical applications of this system are melting point studies and the cyclic annealing of semiconductor devices water bath temperature control conductivity measurement system thermoluminescence measurement system and also suitable for general use 2 SYSTEM DESCRIPTION The block diagram of temperature measurement and control set up is shown in figure 1 The system hardware consists of a k type thermocouple instrumentation amplifier 1C714 12 bit analog to digital converter solid state power control
133. s provided between the level 0 0 and the probe M to facilitate a free vertical movement of mercury level as per the applied differential pressure intensity In the present arrangement the maximum gap provided is 2mm It may be noted that a metallic float can be used in place of mercury meniscus in sump S the details of which are explained later in this paper 2 2 Capacitive Transducer A precise displacement measuring device based on variable capacitance principle with a non contact type transducer is developed and used to measure the air gap AR in the sump S The capacitance between two parallel conductive plates in an electrical circuit varies with the distance between the plates in a fixed relation to the change in distance The main innovations in this component are to make use of either 1 mercury meniscus as a moving plate grounded through G for the purpose in capacitance circuit or ii a metallic float as a moving plate in some other occasions not shown in Fig 1 with 58 Achanta Ramakrishna Rao view to measure accurately and display digitally the air gap AR between a fixed plate the probe M and the movable plate either a mercury meniscus or a metallic float which moves because of the applied differential pressure head AH The capacitance between the transducer and the mercury is detected and compared with a fixed capacitor in a detector circuit The output of the detector circuit is fed to an AC DC converter circuit and
134. sed on the past values to fit the state space model for the middle portion of the distillation column Thus the reduced order is found and refined model is selected using AIC AIC s for various lags and polynomial degrees are calculated by fitting data in the ARX model 10 11 The calculated values for degree 1 is shown in Table 5 The past lag is the one corresponding to the minimum value of AIC which in this case is 5 Using singular value decomposition in CVA the number of nonsingular elements is the rank of the matrix This rank is the order of the model which in the case of middle product turns out to be 4 The calculated AIC values for various orders and parameters are shown in Table 6 The AIC is minimised and its corresponding values gives the optimal state order and the number of parameters Modeling of middle product of a distillation column using akaike information criteria 97 Table 5 The Optimal selection of LAGP for CVA computations is one larger AIC for Degree 1 j Order Parameters AIC 0 1 1355 6549 1 17 2592 9602 2 23 8002 8793 3 29 8997 5000 4 35 9388 6610 5 41 9375 6655 6 47 9362 4771 7 53 9349 0839 8 59 9335 5594 9 65 9321 8160 l0 7 9307 8988 n 7 9293 8078 12 83 9279 5387 Table 6 The Optimal order chosen minimizes the AIC than the Lags of MIN 5 CONCLUSIONS The computation of the nonlinear Canon
135. sefulness of the above equation can best be illustrated by using certain numerical values Thus by taking values of a A 1 10 y 213 6 gmf cm y 1 gmf cm and Y 1 2x10 gmt cm the value of manometer constant Cu 17 48 which is the value of the terms inside the square brackets of Eq 4 As AH is measured with an accuracy of 0 001 mm the differential head AH can be measured with an accuracy of 0 01748 mm of water head or about 1 69 micro bar This is reasonably a sufficient accuracy of measurement for most problems with low pressure heads in pipe and open channel flow experiments As the design value of AZ is up to a maximum of 2mm the range of the differential head AH that can be measured in this model is up to 35 mm of water head with an accuracy of 0 01748 mm In general the measurement accuracy of AH can be increased by decreasing the value of a A where as the range of AH decreases It may be noted here that air can be used as experimental fluid y y instead of water An appropriate equation similar to Eq 4 can be derived from the general Eq 3 as AH AH 143a A Cy Y Y 4a The major advantage of the first model is such that the turbulent fluctuations in the experimental fluid are significantly dampened due to the presence of heavier manometric fluid of mercury in all the four sumps and hence the signal output as seen in the digital display is stable The major disadvantage is the increased cost of the manometer due
136. sion simple logic is used We know that the data 3A H corresponds to the 0 pH value Now if the available data is m then the one register accumulator is loaded with data 39 H it is incremented by 0A H each time and compared with m for increment of pH by unit value the output of the ADC will jump OA H i e 10 places forward Then it is found that how many times OA H should be added to the value 39 H to make it greater than m The number of times is supposing j this j is measured using the counter register Then j 1 t that 1 gives the integer part of pH To get the tractional part of the pH m is subtracted from the data 39 H j OAH which is available in incremented register accumulator Suppose the answer of this is k This K is subtracted from the 09 H Let the answer be n which gives the tractional value digit Finally our real pH value is t n and is stored in one of the register pair In this way any data is converted to its equivalent pH value But the data allowed to display is 0 pH to 14 pH and if hex data goes out of the range 3A H to C6 H then ERROR message is displayed on the display 6 SOFTWARE The algorithm developed for pH measurement using microprocessor is given e Read the data from the ADC e Convert the data in to the corresponding pH equivalent and store integer part in the D register and tractional part in the E register e Use of 8279 by sending different contro
137. stalled The radiation shields are installed in position and this completes the test column assembly The loading pin is lowered gently so as to align the test column properly All the thermocouple circuits are checked for continuity and proper functioning The top heater is switched on and the cooling water is circulated to the bottom cooling coils Adjusting the input voltage to the heater coil through a dimmerstat and constant temperature bath sets the mean interface temperature Adding the dead weights to the end of the lever sets the contact pressure The tests can be conducted by varying the contact pressure in the range of 0 1 to 40 MPa with increments of 0 1 MPa approximately and maintaining the mean interface temperature constant Then the contact pressure can be decreased in steps of 0 1 MPa This completes one load cycle i e one loading and one unloading at a constant mean interface temperature The mean interface temperature is set to the next higher value by increasing the input voltage to the heater coil The loading and unloading processes are repeated in the same manner at each value of the mean interface temperature Similarly tests can be conducted by varying the mean interface temperature and maintaining the contact pressure constant It is also possible to change the direction of heat flow in the test column without disturbing the test specimens In this manner the contact conductance can be measured as a function of contact pressure
138. stance to ensure that the amplifier will work at least with unit gain The offset null is achieved by connecting the 10K ohm preset in 1 4 5 pin s of the OP AMP At 25 C temperature 100K is adjusted to obtain the proper gain of the amplifier For other temperature values the RTD has been used in the feed back path for temperature compensation and WOK works as a temperature calibration knob The output of this amplifier is fed to the sample and hold circuit 4 5 76 B T Jadhav Y S Shinde B B Godabale and S R Sawant 3 4 Sample and hold As the analog output from the sensor is not constant the ADC can t tolerate it to convert it in proper digital equivalent When ADC is reading the input it needs of constant value during the conversion time The sample and hold circuitry will hold the signal at constant level when ADC is converting it in the digital form Using the IC LF 398 with proper choice of hold capacitor and acquisition time does this Acquisition time is the time required to charge the hold capacitor to the new value ftom its previous hold voltage level after logic is made high It is 40 microseconds for the hold capacitor of 0 047 micro fared When the logic input is high it samples the signal and charges the hold capacitor to the certain value and when the logic input is low then the input of IC is tri stated using internal FET The charged capacitor act s as an input source to the internal MOS OP AMP which does not derive any curre
139. stem The RT system was developed on advanced virtual instrumentation environment Tadisetty et al 2002 Therefore software plays a vital role in this innovative new system The RT system was an economically viable and reliable system Since the system developed on virtual environment the system capacity can be extended as and when required The RT system was successfully commissioned at one of the longwall mine GDK Godavarikhani 10A SCCL Ramagundem India for continuous monitoring and analysis of longwall strata behavior and supports performance to effective mining operations The RT system was interfaced to wireless receiver and intelligent dump terminal as shown in Figure 6 The RT system was commissioned on the surface around 25 km away from wireless transmitter Tadisetty et al 2003 The line of sight was maintained for effective data transmissions The RT system was acquired underground sensors data from wireless receiver and displayed on real time monitor after analysis as shown in Figure 6 The detailed discussion on wireless system was reported by the same authors March 2003 in same journal Therefore the more discussions on wireless data transmissions are restricted All the underground powered supports chock shields leg closure and pressure sensors were configured on configuration menu of the RT system The data acquisition time selected was one minute The warning limit selected for chock shields was 400 bars The RT system
140. such a case the following governing equation similar to Eq 5 is derived from Eq 3 AH AZ a A y y hy HAAN Y y 5a 3 3 Third Model This is a very interesting model because the mercury is totally avoided in all the sumps It contains only water and air and one can consider it as an inverted air manometer however with a difference that a metallic float is used in Sump S The probe M and the metallic float forms a capacitance in which M is a fixed plate where as the float is a movable plate and its movement is due to the pressure changes Thus in this model Yo Ym Y Y and substituting them in Eq 3 the governing equation for the third model for water as the experimental fluid is obtained as follows AH AZ 1 a A y 6 By taking the usual values of a A 0 1 and y y 1 02x10 the manometer constant C 1 1 Hence the sensitivity of the instrument is 0 0011 mm or 1 909 of mm of water head because like in all the models AZ is measured with an accuracy of 0 001 mm Even though it has remarkably a very high accuracy but the range of AH is limited only to 2 2mm of water head because the maximum range of AZ is 2mm It is of importance to note that in this model while using water as the experimental fluid cross sectional areas of the sumps S and S have no consequence as they are filled completely with water however cross sectional areas of the sumps S and S can effect significantly the ac
141. t 0 02 ppm level for 5 min and short and long term effects of TDI on respiratory system are available Though the use of TDI may be to the extent of 1 of propellant weight it is observed to adversely affect the health and cause great discomfort to the workers during processing Spillage and exposure is observed to be maximum during transfer weighing of TDI during propellant processing Hence design of TDI transfer and weighing system becomes important in propellant processing To reduce the risk and hazard in transfer of such toxic compounds attempts to do the process automation is continuous in resin and polymer industries However many of the indigenous propellant plants still continue with the manual system Present paper describes a TDI transfer and weighing system designed at HEMRL Pune for using in propellant processing 2 BASIC REQUIREMENTS OF TRANSFER SYSTEM Three aspects of the process requirement are considered in designing the transfer amp weighing system 2 1 Accurate measurement TDI is a critical component in the polymer reactions and accurate quantity has to be incorporated to get repeatable mechanical properties Any deviations can affect the product quality and may lead to major process problems 2 2 Moisture effect TDI is highly moisture sensitive and can react with trace moisture and form impurities deteriorating the product quality and also liberate gases to the environment In addition on prolonged storag
142. t Resistance AIAA Journal vol 21 No 9 pp 1325 1330 1983 9 R S Cook K H Token and R L Calkins A Novel Concept for Reducing Thennal Contact Resistance J of Spacecraft and Rocket Vol 21 No 1 pp 122 124 1984 10 V W Antonetti and M M Yovanovich Enhancement ofthennal Contact Conductance by Metallic Coatings Theory and Experiment Trans ASME J of Heat Transfer Vol 107 pp 513 519 1985 11 M M Yovanovich Theory and Applications of Constriction and Spreading Resistance Concepts for Micro Electronics thennal Management Proceedings of the Int Sym on Cooling Technology for Electronic equipment Pacific institute for Thennal Engineering Honolulu 1987 12 K C Chung J W Sheffield and H J Sauker Jr Thennal Constriction Resistance of Phase Mixed Metallic Coatings Trans ASME Journal of Heat Transfer Vol 114 pp 811 818 1992 13 D Couedel L S Fletcher and G P Peterson A correlation for the Thermal Contact Conductance of interstitial Metallic Foils Proceedings of the 10 International Heat Transfer Conference Brighton U K Vol 6 pp 337 341 1994
143. t conductance as a function of contact pressure is relatively high in the range of 0 1 to 4MPa when compared to that in the range of 4 to 10 MPa This can be attributed to the transformation from plastic to elastic deformation mode due to work hardening of contacting asperities within the range of applied pressure The measured contact conductance of bare joints is less when compared to the joint with metallic foils under the same set of conditions 1 INTRODUCTION Thermal Contact Resistance TCR is an interface resistance between two solid contacting surfaces at different temperatures and is defined as the ratio of temperature drop at the interface to the heat flux Thermal contact Resistance plays a very important role in many engineering applications But even today the estimation of contact resistance is very difficult and even questionable due to its dependence on many parameters like contact pressure mean interface temperature material properties surface parameters interstitial medium etc that influence the contact heat transfer phenomenon SS 304 is an engineering material that is used in many process equipment It is inevitable to have joints and assemblies in the construction of any Effect of Al Metallic foils on Thermal Contact Conductance across Contacts of Stainless Steel 304 115 heat transfer equipment Bare joints offer much greater thermal resistance when compared to joints with sandwiched interstitial materials The use of i
144. t the cooling effectiveness of turbine blade To measure the gas temperature profile at the exit of combustor needs more points of measurements in radial direction for accurate assessing The mounting hole available on test section is just 13mm in diameter The use of any uncooled probe is restricted up to 900 C gas temperature Having considered all the above problems rig testing at high pressures and temperatures of 30 bar and 1500 C demands a complex test vehicle probe that must be water cooled to maintain the properties Two types of Water cooled probes viz Temperature probe and Combination probe were designed fabricated and calibrated against the Master probe Temperature probe has three calibrated shielded R type Pt 13 Rh thermocouples at 3 radial locations and Combination probe has two temperature points and one pressure point at different radial locations This Design and development of water cooled probes to measure pressure and temperature 21 APROBE ASSY c d Fig l Test Section paper describes design considerations errors and calibration details involved in probe development 2 DESIGN CONSIDERATION FOR MEASUREMENT FOR PRESSURE AND TEMPERATURE 2 1 Temperature measurement Care must be taken to minimise errors in gas temperature measurement when a thermocouple is inserted into a fluid The total temperature of a fluid at a velocity V is equal to the thermodynamic temp of a fluid when this fluid is stopped in an a
145. tained for the CFC and NNC is shown in the fig 4a and 4b respectively 4 2 CSTH Temperature Control System The multi step reference tank temperature was given over 600 samples 40 C 45 C and 50 C for 200 samples each The tracking performance for CFC and NNC is shown in the fig 5a amp 5b resp For disturbance rejection test disturbances of 2 C and 2 C were added to the output at the 150th and 350th sampling instants resp The response of both the controllers is shown in the fig 6a amp 6b resp In the third set gf experiments a delay of two samples was incorporated The response obtained for the CFC and NNC is shown in the fig 7a amp 7b respectively It can be observed that the NNCs performed better for all the three sets of experiments The NNC tracked the reference temperature and the rise time is considerably less as compared to CEC The CFC performs poorly for the first set point in case of water bath temperature control system figure 2 The CSTH PI controller tracks the last set point very well but fails badly in tracking first and the second set points figure 5 The CFC actually needs to be retuned The NNC once trained does not require to be trained again The NNC and CFC showed comparable performance in load disturbance rejection in Water Bath System figure 3 but for CSTH figure 6 the NNC outplays the CFC The CFC performed poorly The performance comparison with respect to variable delay also re affirms the superior
146. te Data Acquisition System is designed and implemented for the meteorological variables Solar Intensity and Wind Speed The performance of the system is tested in the laboratory for a distance of 100m The recorded display obtained during the laboratory test is 14 30 54 The Solar Intensity is 1200 w sq m 14 30 54 and the atmospheric wind speed is 0 86 m s REFERENCES 1 Pyranometer CM 11 14 Instruction Manual Kipp amp Zonen UK 2 DELTA T DL2e LOGGER User Manual Version 2 02 Delta T Devices Ltd 128 Low Road Burwell Cambridge CB OFI UK Hot wire Anemometer Testo 490 Manual Testo Instruments UK 4 Micro 51 EB Technical Reference Version 1 0 Vi Microsystems Pvt Ltd Plot No 75 Electronics Estate Perungude Chennai 96 XR 2206 and XR 2211 Datasheets www exar com 6 Manahor Lotia Modem Telephone amp Cordless Circuits Volume 1 BPB Publications New Delhi First Edition 1997 7 National Data Acquisition Data book National Semiconductor Germany 1995 for ADC 0809 J Instrum Soc India 35 1 90 98 MODELING OF MIDDLE PRODUCT OF A DISTILLATION COLUMN USING AKAIKE INFORMATION CRITERIA A Vimala Juliet and S Renganathan Department of Instmmentation and Control Engineering S R M Engineering College Kattankulathur 603203 Tamil Nadu India Bharath Institute of Science amp Technology Salaiyur Tambaram Chennai India ABSTRACT We present an approach that uses Canonical Variate
147. ter wavelength at the centre frequency The expressions for the coupled power and the power into the isolated arm are derived for a presumed power split k 1 between the coupled and isolated powers in the power divider which is matched at the input port The coresponding power expressions are likewise derived for the power combiner 1 INTRODUCTION Wilkinson developed an N way power divider that would split the input power into N output ports and also provide isolation between the output ports The unique feature of the Wilkinson Power divider was the use of resistors connected between the various output ports When the output ports are terminated in the correct load imped ances there is no current in the resistors so they do not absorb any power However if any port is not matched the reflected power from that port is partly absorbed by the resistor network and partly returned to the input but no power is wupled into the other output ports as long as they remain properly terminatedz But the aforesaid elimination of power dissipation in the resistors is possible only at the centre frequency of the power divider The resistors do dissipatc power at other frequencies within the band width of the divider So replacing resistors with transmission lines will reduce power dissipation except for the possible mismatch at the ports which can be taken care of by proper selection of the characteristic impedances of the transmission lines In this
148. teresis i e schmitt trigger The transformer TI with rectifying diodes 01 and 02 delivers unidirectional The low AC voltage is given to pin 2 and 6 of U8 The output of U8 from pin3 is connected to pin2 of triac driver as shown in the figure MOC 304 which incorporates a zero voltage crossing bilateral triac driver providing low power dc control of power triac is used to drive the triac By outputting 0 to 7 to port 2 of microcontroller the duty cycle of oscillator of an U7 can be changed and hence the power to the heater can be varied 4 SOFTWARE SYSTEM When the temperature is being measured a set temperature is read to compute the error The proportional integral and derivative constant of the error are computed individually and their sum the Proportional Integral Derivative PID constant is then calculated and the Design of AT89C52 microcontroller based system for the measurement of temperature and control 103 computed data is sent to 4051 By this the firing angle of the triac can be changed to the desired value and hence the power of the heater Software is developed in assembly language to initialize LCD display to start AQC conversion to check end of conversion to read higher and lower bytes of ADC by enabling LBEN and HBEN signal measure the temperature of the sample indication of over range and sign of data data computation for acquired data storage of data for temperature Flowchart for temperature measurement and contro
149. the column for the revamped capacity The Process flow diagram of a distillation column is shown in Fig 2 The middle product temperatures are tabulated for various manipulated variables by giving step changes The operating point is taken as zero and changes taking place in the variables are scaled with respect to the operating point For example if the operating point of the manipulated variable top pressure is 2 7 kg cm and a step change is given to this manipulated variable the changes in the controlled variable middle product temperature decreases from 219 C to 217 476 C Here 219 C corresponds to 0 and 219 476 C would corresponds to 1 524 as recorded in Tables 3 STATE SPACE MODEL AND CANONICAL VARIATE ANALYSIS Data collected from the petroleum industry are the time series data which consist of output variables Y and input variables U as shown in Table 1 The first step in statistical procedure is to fit the ARX model using these input and output variables to find parameters like past lags p and degree d as described later in this section This past lags and degree are used in canonical variate analysis to determine the order K of the system 3 Then the State Space model for the Distillation column is fitted using Markov s process 4 92 TP TRE 0 000 odoo 000 0 004 0 000 0 080 0 098 L710 1 773 934 0264 0 180 1941 amp 271 0 184 4 27 9 1 065 0 288
150. the purpose of this paper to design and develop a test facility in the light of the recommendations of Snaith et al 3 METHODOLOGY MEASUREMENT PRINCIPLE Thermal contact resistance is defined as a ratio of the temperature drop across the interface to the average heat flow rate through the interface Mathematically it is expressed as the following Rc AT Q hc M Aa Rc Thermal contact conductance hc is the reciprocal of the product of the nominal contact area Aa and contact resistance Rc To estimate thermal contact resistance or contact conductance the knowledge of A T and Q are required The average heat flow rate Q is determined from an arithmetic average of heat flow rates Q and Q passing through the upper and lower heat flux meters The heat flow rates Q and Q are estimated from the least square fits of the measured temperatures along each heat flux meter shown in Fig I Q k Aa dT dx Q k Aa dT dx ea 108 V Vasudeva Rao R Raghukulender and M V Krishna Murthy Where k and k are the known thermal conductivities of the heat flux meters and dT dx and dT dx are the temperature gradients obtained using least squares fit of the measured temperatures by thermocouples The interface temperature drop AT is determined by linear extrapolation of the temperature profiles to the interface of the test specimens D vii i ACT A an a
151. they are characterized for surface parameters using a Taly Surf surface roughness tester Test Column Assembly The test column consists of two similar test specimens a 20um thick aluminium foil two similar heat flux meters made of SS304 two heater cooler blocks made of electrolytic E F t FE CREPE ALE PL XE m l p i i LET ETE ELE ELEME Fig 1 Test Column Details 1 Loading pin 2 Upper end plate 3 MS Bush 4 Tie rod 5 Heater Coil 6 Heater Cooler block 7 Thermocouple 8 Teflon insulation 9 Radiation Shields 10 Heater Cooler block 11 Copper cooling coil 12 SS 304 washer 13 Ball and conical seating arrangement 14 Stack of SS 304 washers 15 Lower end plate H1 Hop Heat Flux Meter S1 Top Specimen S2 Bottom Specimen H2 Bottom Heat Flux Meter Effect of Al Metallic foils on Thermal Contact Conductance across Contacts of Stainless Steel 304 117 grade copper and two pairs of ball and conical seating Aluminium foil is sandwiched between two test specimens These are stacked as shown in the Fig 1 such that the test column is exactly symmetric about the interface formed between the test specimens The test specimens and the heat flux meters are inserted in a 6mm thick Poly Tetra Fluoro Ethane PTFE tube which has a vertical slit in its wall The test column is then inserted between the heater and cooler blocks All the interfaces thus formed except the test inte
152. to large amounts 60 Achanta Ramakrishna Rao of expensive mercury in all the four sumps It may be noted that about 2 to 3 kgf of mercury is required for a A 0 1 for the manometer shown in Fig 1 It is experienced that the cost of the mercury itself is about 25 of the total cost of manometer in this model In the next models attempts are made to reduce or totally avoid the use of mercury in the sumps there by reducing the cost of making the micro manometers 3 2 Second Model In this model the usage of mercury is reduced to half when compared to the first model Here mercury is avoided in the sumps S and S by allowing the experimental fluid itself to get filled in those two sumps Except this change all are kept identical to the first model Hence by making use of Y y and y y the following governing equation for this second model is obtained when water y y is used as the experimental fluid as AH AZ 1 a A y 7 d By taking values of a A 1 10 y 213 6 gmf cm y 1 gmf cm and y 1 2x10 gmf cm the value of manometer constant is C 214 96 The accuracy of AH measurement is 0 01496 mm of water head and its range is up to a maximum of about 30mm The second model is more economical than the first model because of the reduced quantities of mercury Also there is a slight improvement in the measurement accuracy of AH In this model too air can be used as an experimental fluid y y instead of water and in
153. ty Kikuo Matsui and R N Gupta Chock shield C64 setting pressure was 338 bars initially at 20 02 hrs on 27 April 2002 as shown in Figure 8 The pressure suddenly increased and then decreased and again increased and decreased between 20 32 to 22 00 hrs due to periodic falls in the goal behind the support The chock shield pressure returns back to setting pressure at 23 09 hrs The chock shield was near the tailgate The RT system was successfully evaluated the chock shield performance and initiated warning module during the periodic falls Support C35 behavior on 20th March 2003 o 5 500 2 400 300 200 3 100 E 0 Eo oq 4 d wo o WS ah X X nD 4 d X 4X nO X Elapsed time hrs min Fig 8 Chock sheld C64 behavior on 27th April 2002 Support C30 behavior on 27th March 2003 7 E 450 350 o 250 5 150 2 50 E 50 o o y bs S o 9 o N X b S 4 Pie Ww dw 6 S SU GN NO 4 4 cM 0 o aY Q S NN xv gt AS S SY S S Y qv Y Elapsed time hrs min Fig 9 Chock sield C64 behavior on 27th April 2002 The setting pressure of C35 chock shield was 380 bars at 8 23 hrs on 20 March 2003 as shown in Figure 9 It was advanced at 12 24 16 25 19 25 and 20 25 hrs The support pressure was reduced to 150 bars at 14 24 hrs due to face hydraulic leakage Support pressure was yielding from 15 24 to 21 25 hrs due to periodic weight The support was in the centre of the panel The RT system was successfully forecasted the
154. uctures from built in LabVIEW VI libraries Wires are connected each of the nodes on the block diagram including control and indicator terminals functions and structures Palettes LabVIEW palette gives the options need to create and edit the front panel and block diagram Palettes are of two types They are tools and controls palette Tools palette The tools palette is available on the front panel and the block diagram A tool is a special operating mode of the mouse cursor When tool is selected the cursor icon changes to the tool icon The tools are used to operate and modify front panel and block diagram objects Controls palette The controls palette is available only on the front panel The controls palette contains the controls and indicators to create the front panel Functions palette The functions palette is available only on the block diagram The functions palette contains the VIs and functions to build the block diagram All the palettes can be placed anywhere on the screen 12 Srinivasulu Tadisetty Kikuo Matsui and R N Gupta 3 LABVIEW MENUS Only three software menus are required for implementing real time operations These menus also called real time menus Three menus were developed on LabVIEW programming environment They are main menu configuration menu and processing menu as shown in Figuresl to 3 All these menus were successfully incorporated in RT system These menus were facilitated the user friendly operations
155. unters are used for e Number of times the program has executed the delay loop of 3 ms in order to find out whether the pulse is logical 0 or 1 or a position marker e Keeping a count of the pulses in a given sub frame e Identifying two successive position markers After this the program idles in a wait loop until an interrupt pulse is detected at RST 7 5 pin of the CPU On detection the program jumps to the location in EPOM where the instructions for RST 7 5 are written executes them and returns to the wait loop Fig 4 Photograph of the IRIG B Decoder 38 A K Hanjura 4 2 Interrupt Service Subroutine RST 7 5 This subroutine is serviced when the input pulse arrives This subroutine does the following e Executes a 3 ms delay loop till the input level becomes zero A counter keeps track of the number of times the loop is executed If the loop is executed only once it is 0 bit if executed twice it is l bit otherwise it is a position marker e Looks for two successive position markers for the start of a frame e Checks the widths of data bits and places them in appropriate places e At the end of five sub frames it converts the stored data into BCD numbers e Runs the display subroutine to display the BCD numbers 5 CONCLUSION The decoder based on the above design was developed and operated The cards designed and the interconnections are photographed as shown in fig 4 6 REFERENCES 1 A Sen Gupta A K
156. usly and applied to Indian mining applications to effective and efficient longwall operations ACKNOWLEDGEMENTS The SCCL Singareni Collieries Company Limited management and Department of Coal Government of India was strongly acknowledged for supporting field experimentation and providing necessary funds respectively Further acknowledged the Japan Society for Promotion of Science for approving fellowship to carry out the research at Kyushu University The views expressed in this paper are those of the authors and not necessarily of the organization they represents REFERENCES 1 Y M Jiang D W Park D Deb and R L Sanford Development of on line evaluation of longwall roof behavior using neural networks and fuzzy sets Journal of society for mining metallurgy and exploration 1996 2 Srinivasulu Tadisetty Kikuo Matsui and Gupta R N Virtual instrumentation for real time analysis of supports behavior Journal of mines metals and fuels special issue on annual review 2002 December 2002 3 Srinivasulu Tadisetty Kikuo Matsui and Gupta R N Frequency hopping techniques for reliable geomechanical data transmission Journal of the instrument society of India Vol 33 No 1 15 March 2003 4 Thomas M Barczak and David C Oyler A model of shield strata interaction and its implications for active shield setting requirements USBM RI 9394 1991 J Instrum Soc India 35 1 20 27 DESIGN AND DEVELOPMENT OF WATER COOLED PRO
157. ved output buffer is enabled and digital data is read in the one of the port of 8255 lastly output buffer is disabled 3 5 1 Dual range working for the ADC As the sensor and amplified voltages are bipolar Ve as well V e the ADC should handle these voltages properly 6 7 It can be achieved by using both Ve and Ve reference levels but the other channels may not have any need of working in the bipolar range The external voltage divider network is used and the input given to the channel should remain Ve for the maximum Ve input voltage of the divider If the Vcc is the Ve reference voltage amp zero or Ground is the V e reference voltage then first the input voltage is made of its half and it is then clamped at V cc 2 so that the range of the input that can be given to the voltage divider is Vcc hence the ADC can be used in the dual range Table I shows actual voltages applied the voltage at the channel and its converted hex equivalent Microprocessor Based pH Measuring System TI Input votlages Voltages at the channel Hex Equivalent 5 0 00 0 2 5 80 5 5 FF Table I Voltages applied and converted Hex equivalent 3 6 Microprocessor The 8085 microprocessor kit manufactured by Anshuman is used Its working frequency is 3 MHz It has facility of reading amp writing and has 8 digit seven segment LED displays which can be controlled by using the keyboard and display interface using the support
158. was initiated inbuilt warning modules whenever the support pressure crosses warning limit threshold The real time display was updated for every minute with the latest information of strata and supports This information was facilitated to management for taking prompt decisions for implementing precautionary measures to effective mining operations The real time display was includes cluster of various informations like underground sensors and strata and supports behavior as shown in Figure 6 The underground sensor display information was includes type location units calibration date of commissioned and date of replaced The chock shields display information was includes setting pressure yield pressure supply pressure hydraulic circuit failures influence of shearer cutting influence of adjacent shield advancement and dynamic loading in graphically and numerically as shown in Figure 6 Further the numerical display was indicates the rate of change in parameters The display of strata behavior was includes caving of immediate and main roof face spalling stress levels in face and cavities All the aforesaid information was continuously updated for every minute promptly after detailed analysis on real time The RT system was initiated warning modules during adverse behavior of strata and supports for implementing necessary precautionary measures to avoid safety and productivity loss The RT system was successfully recorded behavior of strata and su
159. wave Engineering Mc Grew Hill 1992 2 PA Rizzy Microwave Engineering Passive circuits Prentice Hall 1988 J Instrum Soc India 35 1 73 83 73 MICROPROCESSOR BASED pH MEASURING SYSTEM B T Jadhav Y S Shinde B B Godabale and S R Sawant Department of Electronics Yashwantrao Chavan Institute of Science Satara 415 001 M S Department of Electro nics K B Patil College of Engineering amp Polyte Satara 415 001 M S Department of Electronics Shivaji University Kolhapur 416 004 M S ABSTRACT In many processes accurate measurement of pH value and its control is the important phase To measure the desired level of pH different techniques are in use designed for specific type of electrode and signal conditioning Here we design and develop the microprocessor based pH measuring system which has good acquisition time and accuracy 1 INTRODUCTION The pH quantity pH log Hl shows the hydrogen Hl ion concentration indicates whether given solution is acidic neutral or basic The pH is an important parameter in various chemical and electrochemical processes In many industries it becomes necessary to measure and control accurately the value of pH For e g In Sugar industry at the clarification processes the measurement and control of pH of cane juice is very important There are so many references on the developments of pH meters So many of them are based on the analog as well as digital circu

realization of active filters using operational transconductance

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