2900-218-R Report of Project MICHIGAN USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEMPERATURE DISTURBANCES PHILIP L. JACKSON Jannuary- 1961 Fluid and Solid Mechanics Laboratory fu^Utitue i^ Saer~te EaWCe 7ec4o91 THE UNIVERSITY OF MICHIGAN Ann Arbor, Michigan

NOTICES Sponsorship. The work reported herein was conducted by the Institute of Science and Technology for the U. S. Army Signal Corps under Project MICHIGAN, Contract DA-36-039 SC-78801. Contracts and grants to The University of Michigan for the support of sponsored research by the Institute of Science and Technology are administered through the Office of the Vice-President for Research. Distribution. Initial distribution is indicated at the end of this document. Distribution control of Project MICHIGAN documents has been delegated by the U. S. Army Signal Corps to the office named below. Please address correspondence concerning distribution of reports to: U. S. Army Liaison Group Project MICHIGAN The University of Michigan P. 0. Box 618 Ann Arbor, Michigan ASTIA Availability. Qualified requesters may obtain copies of this document from: Armed Services Technical Information Agency Arlington Hall Station Arlington 12, Virginia Final Disposition. After this document has served its purpose, it may be destroyed. Please do not return it to the Institute of Science and Technology. ii

Institute of Science and Technology The University of Michigan PREFACE Documents issued in this series of Technical Memorandums are published by the Institute of Science and Technology in order to disseminate scientific and engineering information as speedily and as widely as possible. The work reported may be incomplete, but it is considered to be useful, interesting, or suggestive enough to warrant this early publication. Any conclusions are tentative, of course. Also included in this series will be reports of work in progress which will later be combined with other materials to form a more comprehensive contribution in the field. A primary reason for publishing any paper in this series is to invite technical and professional comments and suggestions. All correspondence should be addressed to the Technical Director of Project MICHIGAN. Project MICHIGAN, which engages in research and development for the U. S. Army Combat Surveillance Agency of the U. S. Army Signal Corps, is carried on by the Institute of Science and Technology as part of The University of Michigan's service to various government agencies and to industrial organizations. Robert L. Hess Technical Director Project MICHIGAN iii

Institute of Science and Technology The University of Michigan CONTENTS Notices................................ ii Preface...............................iii Lists of Figures and Table....................... vi Abstract............................... 1 1. Introduction............................ 1 2. Analysis.............................. 1 3. Experiments........................ 4 3.1. Discrete Heat Source Applied to an Unheated Long Junction 5 3.2. Small Cooling Jet Applied to a Heated Long Junction 5 3.3. Mixing of Boiling and Freezing Water 8 3.4. Measurement of Liquid Level 8 3. 5. Discrete Heat Source Location in Two Dimensions 10 4. Discussion............................ 11 Appendix A: Voltage Reference for a Long Thermocouple........ 12 Appendix B: Voltage Decrement for a Large Flat Thermocouple...... 13 Distribution List............................ 15

Institute of Science and Technology The University of Michigan FIGURES 1. Construction of Long Thermocouple.................. 2 2. Construction of a Large Thermocouple of Two Flat Elements...... 4 3. Long Iron-Constantan Thermocouple Voltage Differences between Constantan Leads at Each End.................. 6 4. Long Iron-Constantan Thermocouple Voltage Differences between Various Leads..........................7 5. Oscillograph Time History of Long Thermocouple Output in Mixing of Boiling with 0~ C Water...................... 8 6. Long Iron-Constantan Thermocouple Water-Level Indication....... 9 TABLE I. Voltages across the Two Diagonals of A 1 x 0. 9-Inch NichromeAluminum Thermocouple.....................10 vi

USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEMPERATURE DISTURBANCES1 ABSTRACT A temperature disturbance within a large thermocouple junction produces a voltage which decreases with distance from the disturbance. With proper junction geometry, resulting voltage residues may be compared at two or more points on the junction. Positions and magnitudes of temperature disturbances are thereby determined. Useful measurement applications result. 1 INTRODUCTION This report describes a unique use of a common sensing device-the thermocouple. Unlike the customary thermocouple junction, which measures temperature at a point, the large thermocouple junction locates temperature disturbances within the junction. A temperature disturbance at a point located on a large thermocouple junction will produce currents which fall off with distance from disturbance. Residual potential differences between selected leads indicate the location of the disturbance. The voltage residues so produced can be used advantageously for a number of measuring applications. These include measurement of the magnitude and position of discrete heat sources, liquid level, fluid mixing, velocity gradients, and temperature equilibrium over a continuum. A large thermocouple may also be used to measure the atmospheric turbulence which deteriorates infrared and radar information in combat surveillance. Analysis of the voltage potentials in a large thermocouple junction and confirming experiments are presented in this paper. 2 ANALYSIS A special case of the large thermocouple junction is shown in Figure 1. This is a long junction, electrically equivalent to a transmission line.'The author appreciates the help of W. C. Meecham and V. L. Larrowe for discussions and suggestions concerning this work. 1

Institute of Science and Technology The University of Michigan The transmission-line equation E =E sech JRGx (1) o x where E is voltage generated x E is output voltage at end of junction R is resistance per unit length of element x is the distance from source to end of junction G is conductance per unit length between elements describes the voltage decrement from the disturbance to the end of a long junction. A large thermocouple junction may be viewed as a number of nonadditive point thermocouple junctions placed along a transmission line. A temperature disturbance causes a voltage to be generated at one of these points. This voltage decreases with distance along the junction due to current leakage between elements. Position of Temperature Disturbance Generating Ex Thermocouple Element A / 7a D /\ / at ba / bx Thermocouple Element B FIGURE 1. CONSTRUCTION OF LONG THERMOCOUPLE Figure 1 illustrates a long thermocouple junction constructed by twisting, soldering or fusing two wires together. Five fixed leads are shown in Figure 1: a, a', a", b, b', four located at the junction ends and one at a distance from an end. If a temperature disturbance occurs at point x, generating a voltage Ex, the two leads from the left end of the junction will produce a voltage difference of E sech'RG x. x 2

Institute of Science and Technology The University of Michigan Since elements A and B may have different values of resistance per unit length, a referRb ence voltage level of + R E above element B at point x is taken (see Appendix A). R is R + Rb x a a b resistance per unit length for element A, and Rb for element B. Letting iG = K, the voltages Ea, Ea,, E,, Eb, E,, at locations indicated by the subscript, follow: a a a b' b R E = a E sech Kx (2) a R + R x a b a (3) a R +b x R R + R Ex sech K(1 - x) cosh K(1 - 2) x< e2 (4) Ea" R +Rb x 1 a b R Ea =R + R Ex sech Kx cosh Ke2 x > (4a) b R +Rb x Rb Eb' = -R R E sech K( - x) (6) a b The voltage differences between leads are readily found by subtracting the value at one lead from the value at another. For instance, the voltage difference between lead a and lead a' is E - E -. Ex sech Kx - sech K(1 - x) (7) a a' R a +Rb L A voltage difference of zero occurs at x = 2 e. For the two-dimensional junction of the voltage decrement is described by the equation E gE 2 e e- x (8) 0 xf 7rg x for large value of x when edge effects are ignored (see Appendix B). r is resistance per unit square, g conductance per unit area. Thus, if the junction in Figure 2 extends sufficiently beyond the edges shown, the voltagedifferencebetweentwo leads on element A at the corners c,d is 3

Institute of Science and Technology The University of Michigan - - Xrg c -g xd 2 e e E E e(9) c Ed= r g ) Also, I-rgx Xe i xf EE f= g -E e- e (9a) Ee - Ef= 41rEX 0 W q j (9a) Thus a location on a plane may be found. Position of Temperature Disturbance Generating Thermocouple Element A "x' Vx c f e Xd e Thermocouple Element B FIGURE 2. CONSTRUCTION OF A LARGE THERMOCOUPLE OF TWO FLAT ELEMENTS. Distance from point x to leads c, d, e, f shown at corners of element A. 3 EXPERIMENTS Five experiments were performed to confirm the basic idea of using a large junction for position measurement, and to explore its applicability to several measurement applications. These experiments were preliminary in the sense that they were only intended to explore the measurement possibilities of a large thermocouple junction, and they do not exhaust the possible applications of this device. Ultimate sensitivity and accuracy were not investigated, nor were refinements for particular applications. Therefore, such techniques as linearizing by varying resistance or conductance in the junction, using many leads along a junction, using focused radiation for a heat source, or varying the impedances of the measuring instruments were beyond the scope of this effort. 4

Institute of Science and Technology The University of Michigan Measurements were made with a Leeds and Northrup K-potentiometer and a 2430-A galvanometer in all but the fluid-mixing experiment, for which a Consolidated Electrodynamics Model 9-116 oscillograph with a 5-315 galvanometer was employed. 3.1. DISCRETE HEAT SOURCE APPLIED TO AN UNHEATED LONG JUNCTION A discrete heat source was applied at various positions along junctions approximately 10cm long. Voltage residue differences between pairs of the four end leads were plotted against the positions of the heat source. These experiments were performed to determine the dependence of voltage outputs on heat position and to give a basis to the above theory. Long thermocouples were constructed of iron-constantan elements by twisting or soldering two parallel wires. Three wire sizes were used. The junction rested upon a large aluminum block insulated by 0. 001-inch Mylar tape. Heat was conducted to a small portion of the couple through a wire attached to a 60-watt soldering iron. A lathe bed was used to position the heat source. Results are shown in Figures 3 and 4 in the form of millivolt outputs between various pairs of leads plotted as functions of heat source position. In each case, the output is seen to be dependent upon the position of the applied heat source. In Figure 3, the voltage between two end leads of the same element (E - E, of Figure 1) is of similar magnitude and opposite polarity a a when heat is applied at opposite ends of the couple. A null voltage occurs when the temperature disturbance is near the center. This corresponds to Equation 7. In Figure 4, the voltage between leads of opposite elements at one end of the long couple (E - Eb of Figure 1) is at a a o maximum when heat is applied at this end. As predicted in Equations 2 and 3, the voltage decreases as the heat source moves toward the opposite end. Figure 4 also shows the voltage between opposing elements at opposite ends of the junction (Ea - Eb, of Figure 1). With heat at one end, the voltage is relatively large. Its lowest value is near the center, and its maximum value is at x = e1. Since element B (constantan) has a higher resistance than element A (iron), this result is expected considering Equations 2 and 6. 3.2. SMALL COOLING JET APPLIED TO A HEATED LONG JUNCTION A long junction was heated for the purpose of locating heat conduction anomalies. This use of a heated junction extends the measuring possibilities to environments where no temperature disturbance normally exists. A small jet of air was placed on the junction at various distances from the ends. The cooled spot from the jet resulted in thermoelectric voltages of opposite polarities from those found in Type 1 experiments. 5

Institute of Science and Technology The University of Michigan 6 -60 5 -50 4 1 2 3 40 0 2 20 Z — 4 (cm) -1 20 B & S gauge, twisted, unbonded ~~~6~~~~~~ —0 -5 0 2I - 320 -3 30 B & S gauge, twisted, unbonded ~ 2 3 4 5 6 7 8 9' lo Heated by { * 30 B & S gauge, twisted, unbonded metal contact * 20 B & S gauge, twisted, unbonded * 20 B & S gauge, twisted, unbonded Cooled by 0. 5- f A 30 B & S gauge, not twisted, soldered, cm-diameter air jet ~ heated by 1.25-amp, 1000-cps current (~~~~

Institute of Science and Technology The University of Michigan c j 0 I t o _ I I I I I I 1 2 3 4 5 6 7 8 9 10 DISTANCE OF TEMPERATURE DISTURBANCE FROM END (cm) FIGURE 4. LONG IRON-CONSTANTAN THERMOCOUPLE VOLTAGE DIFFERENCES BETWEEN VARIOUS LEADS * 30 B & S gauge, twisted, unbonded, iron against constantan at end x = 0 O 24 B & S gauge, twisted, unbonded, iron lead at x = 0, constantan lead at x = e * 20 B & S gauge, twisted, unbonded, iron lead at each end 7

Institute of Science and Technology The University of Michigan Joule law heating (1. 25 amp at a frequency of 1000 cps) was applied across the thermocouple junction. The air jet-0. 5 cm in diameter with a velocity of 6. 5 x 10 cm/sec-was positioned with a micrometer actuated lathe bed. Figure 3 shows the output across the two constantan end leads as a function of position. These results are predicted by Equation 7, and indicate that the long thermocouple junction is capable of measuring other than temperature disturbances-in this case a fluid flow disturbance. 3.3. MIXING OF BOILING AND FREEZING WATER The large thermocouple is particularly adapted to measuring gross temperature balance. To illustrate such an application, boiling and freezing water were stirred together until temperature equilibrium resulted. Figure 5 is the reduction of an oscillograph time history of the temperature balance in the mixture. Two constantan end leads of a 30-gauge iron-constantan thermocouple 10 cm long were used. The mixing container was a 12 x 10 x 1 3/4-inch plastic tray. Temperature equilibrium was reached in 70 seconds. The temperature variations along the junction were of the same frequency as the mixing strokes. 0. 5 in. /sec 0. 32 mv/in. I-< —----—, —-- ~70 seconds --- --- FIGURE 5. OSCILLOGRAPH TIME HISTORY OF LONG THERMOCOUPLE OUTPUT IN MIXING OF BOILING WITH 0~ C WATER Thus the degree of temperature balance over a continuum is shown. Its frequency, magnitude, polarity, and damping are indicated from a time history. 3.4. MEASUREMENT OF LIQUID LEVEL A large thermocouple may be used to locate an interface between two substances. To illustrate this application, the water level in a container was measured by means of a heated long junction. Measurement was possible because the water-immersed portion of the junction cools faster than that remaining in air. 8

Institute of Science and Technology The University of Michigan Again,Joule law heating (1. 25 amp at a frequency of 1000 cps) was applied to the junction. The heated 30-gauge iron-constantan junction was supported vertically, and the water level was raised and lowered. Also, the results of minute water-level changes were observed. The resolution was limited by air currents in the room. The results in Figure 6 show that the voltage output is a function of water level. A voltage R output of the form R +R —-- -- E [ 1 - sech K (e - x)] is caused when end ab is immersed (see a b 80 0 70 -70 a 60- 60 - Q z w z z Iz 0 40 / 40 H 1? / \ %z \0 30 30 4 0 o ^ 20 20 > H Z 10 00//*A — 10 U 0^ \ 0 2 4 6 8 10 12 14 16 18 WATER LEVEL (cm) 0.01 0.02 0.03 0.04 SMALL CHANGE IN WATER LEVEL (cm) FIGURE 6. LONG IRON-CONSTANTAN THERMOCOUPLE WATER-LEVEL INDICATION Water level increased t Water level decreased -- -* Small change in water level (uiv changes) 9

Institute of Science and Technology The University of Michigan Figure 1). x is the position of the interface. Lead a (Figure 1) always responds as if the temperature disturbance were at x = 0, because the end of the junction is the same temperature as that close to the interface. 3.5. DISCRETE HEAT-SOURCE LOCATION IN TWO DIMENSIONS In this experiment temperature disturbances in two dimensions were investigated to demonstrate that the first four types of measurements can be extended to a surface from a length. In this case a rectangular plane was employed, but the type of surface does not appear limited. For example, a spherical or cylindrical surface could be employed. A 1 x 0. 9-inch rectangle of 0. 001-inch Nichrome was taped to a commercial-grade aluminum plate. Copper-wire connections were taped to each corner of the Nichrome element. A sharpened 60-watt soldering-iron point was then placed at the indicated positions (Figure 2). The voltage outputs across the two opposite pairs of corners are recorded in Table I. TABLE I. VOLTAGES ACROSS THE TWO DIAGONALS OF A 1 x 0.9-INCH NICHROME-ALUMINUM THERMOCOUPLE A: -.32 + 3.85 + 5.76 + 12.2 + 30.8 + 160.0 0. 9 B: - 128.0 - 14.5 - 6.72 -3.85 - 0.64 + 2.64 A: - 4.50 - 7.05 + 2.63 + 12.2 + 18.0 + 128.0 0. 8 B: -80.0 - 23.2 - 6.4 - 0.64 - 1.93 + 3.22; 0. A: -1.28 + 0.64 + 1.28 + 3.85 + 8.00 + 4.50 0.6 o B: +1.93 - 12.2 - 8.40 -5.14 0.32 + 1.24 U 0 4 A: -3.80 - 2.30 0 + 2.30 + 4.17 + 9.62 0.4 ~ _B: -6.73 - 3.80 -5.10 - 1.93 + 0.64 + 2.63 z A: - 12.8 - 10.25 - 4.50 + 1.93 0 + 1.93 0. 2 B: -0.96 - 3.52 - 0.64 + 1.28 + 3.70 + 8.66 A: - 48.2 - 20.0 - 10.25 - 11.0 - 4.80 + 3.20 0 B: + 3.80 0 + 3.80 + 9.60 + 27.0 + 145.0 0 0.2 0.4 0.6 0.8 1.0 INCHES FROM CORNER Boxes indicate position of applied heat. A is voltage between 0, 0 and 1, 0. 9. B is voltage between 0, 0. 9 and 1, 0. 10

Institute of Science and Technology The University of Michigan This rough experiment indicates that position measurement is possible on a surface as well as on a length. It is thus concluded that a temperature disturbance corresponding to a point on the surface of a large thermocouple can be located by means of voltage residues. 4 DISCUSSION These preliminary experiments introduce the kinds of measurements possible with the large thermocouple junction. However, they also expose several limitations and difficulties. Because of the nature of the voltage decrement, linearity is difficult to achieve. Two approaches are possible. First, a relatively low resistance and low conductance in a junction allows the use of only a small portion of the decrement. Thus, as shown in Figure 2, the curve referring to the largest diameter of thermocouple (lowest resistance) is the closest to a linear curve. The second approach is to adjust the resistance or conductance so that the value (RG)1/2 in Equation 1 varies with distance x in such a manner that sech iRGx= 1 - Kx, where K is a constant. The experiments also indicate that accuracy depends upon the type of junction and the uniformity of heat conduction to the junction. Thus, the twisted and unbonded junctions produce more erratic data points than the straight, soldered junction. The variations in conductivity between the elements and the difficulty of reproducing heater conduction to the twisted wires degrade the data. Additional limitations are caused by the finite width of the heat source, conduction of heat along the junction, and the difficulty in maintaining constant temperature over the nondisturbed portion of the junction. These provide obvious obstacles to accuracy. 11

Institute of Science and Technology The University of Michigan Appendix A VOLTAGE REFERENCE FOR A LONG THERMOCOUPLE The voltage decrements are unequal in two elements with different resistivities. As distance from the generating point is increased, the voltage in each element approaches asymptotically a voltage level which serves as a reference voltage for the entire length of the junction. At the position of this reference voltage, current flows only perpendicularly from one element to the other. The voltage generated in element A is E, and in element B the voltage is Eb. As the reference voltage level is somewhere between E and Eb, E is posibD'~~~~~ ~a b a tive, and Eb is negative when element A is positive with respect to element B. 1/2 1/2 The propagation constant for element A is (RaGa), and for element B is (RbGb)/ As the form of the voltage decrement is the same in each element, the following equality holds at the end of the junction: sech R G )t/2x = sech (RbGb/2x where x is the distance to the temperature disturbance from the junction end. From this, R G= RbGb (10) The size of the voltage decrement in each element is determined by the magnitudes of E and a Eb. The change in current along the junction is due to conductance between the elements, and is therefore equal in magnitude in both elements. The current change is the voltage at x divided by the characteristic resistance: E sech G 1/x cosh aGa)/ xdx E sech G x cosh ( xdx a a a a b b b b b x (R /G a/2 (R/G,)/2 (11) where x is the distance of the temperature disturbance from the measuring end of the junction. The sech function represents the voltage decrease from x to the end of the junction, and the cosh function represents the voltage increase from the end of the junction to the variable distance x. Through the differentiation of Equation 2 and the use of Equation 1 to remove the hyperbolic functions, it is found that 12

Institute of Science and Technology The University of Michigan (R G 1/2 (RbGb)1/2 ( a a) (E b b E, / 1/72 a (, 1/)'/2 Eb and therefore, E Gb R a a _b _ Eb G Rb b a b As the generated voltage is E =E -E,=E 1 + x a b =a\ R then R E a E a R + Rb x a b and Rb Eb = R REx a b Appendix B VOLTAGE DECREMENT FOR A LARGE FLAT THERMOCOUPLE The voltage decrement between two infinite plates of resistance r per square and conductance g per unit area is derived as follows. An annulus; with center at the voltage source position, with radial thickness Ax, and average circumference 2rx, is considered. The resistance from the inner to the outer edge of the annulus is rAx/ 27rx, giving a voltage drop of AE = -I(rAx/ 2rx); so that, in the limit, dE/dx = -Ir/27rx, where I is current from the inner to the outer edge of the annulus. The conductance is gAx27rx, giving current between the plates of AI = EgAx27rx in the annulus; in the limit, this becomes d = - Eg2arx as dE Ir dx 271 13

Institute of Science and Technology The University of Michigan d dE\ dI r = RgxE dx dXcI - dx 2 Rg and d2E 1 dE d +x-dE- rgE =. dx Let x' = i \ rgx dx' dx =i^^Tg where i = \-1. Then d2 E rgdE rg x,2 x'dx' When the common factor (- rg) is removed, the solutions of this equation are Bessel functions. The solution for x large is found by the real part of the Hankel functions. AH 1) + BH0(2) 0-v The real part of H ) is iH(1) = [iJo(i rgx) + iNo(i Irgx)] i ^ exp (ii -rgx) exp - vrgix exp (-i ~ i -- exp (- Rx as exp_( 4 1 i - i iH(1) ~ 2 exp(- gx) H0 - f 1TY rgxX and as H(2) = J(i Yrgx) - iN0(i rxgx) diverges, B = 0, and A = E0. Therefore, E ~ E 0 ~Fgx exp (-'-Yx), for x large. 14

Institute of Science and Technology The University of Michigan PROJECT MICHIGAN DISTRIBUTION LIST 7 1 January 1961- Effective Date Copy No. Addressee Copy No. Addressee 1 Army Research Office, ORCD, DA 56 Commandant, U. S. Army Infantry School Washington 25, D. C. Fort Benning, Georgia ATTN: Research Support Division ATTN: Combat Developments Office 2-3 Commanding General 57-58 Assistant Commandant U. S. Army Combat Surveillance Agency U. S. Army Artillery & Missile School 1124 N. Highland Street Fort Sill, Oklahoma Arlington 1, Virginia ~Arlington 1, Virginia ~59 Assistant Commandant, U. S. Army Air Defense School 4-40 Commanding Officer Fort Bliss, Texas U. S. Army Signal Research & Development Laboratory 60 Commandant, U. S. Army Engineer School Fort Monmouth, New Jersey Fort Belvoir, Virginia Fort Belvoir, Virginia ATTN: SIGFM/EL-DR ATTN: ESSY-L 41 Commanding General 61 Commandant, U. S. Army Signal School U. S. Army Electronic Proving Ground Fort Monmouth, New Jersey Fort Huachuca, Arizona ATTN: SIGFM/SC-DO ATTN: SIGPG-DXP 62 Commandant, U. S. Army Aviation School 42 Commanding General Fort Rucker, Alabama Quartermaster Research & Engineering Command U. S. Army, Natick, Massachusetts 63-64 President, U. S. Army Intelligence Board 43 Chief, Human Factors Research Division Fort Holabird, Baltimore 19, Maryland Office of the Chief of Research & Development Department of the Army, Washington 25, D. C. 65 Commanding Officer, U. S. Army Signal Electronic Research Unit, P. 0. Box 205 44-45 Commander, Army Rocket & Guided Missile Agency Mountain View, California Redstone Arsenal, Alabama ATTN: Technical Lirary, ORDXR-OTL 66-69 Office of Naval Research, Department of the Navy 17th & Constitution Avenue, N. W. ~~~~~46-47 ~~Commanding Officer ~Washington 25, D. C. 46-47 Commanding Officer U. S. Army Transportation Research Command (66-67) ATTN: Code 463 Fort Eustis, Virginia (68-69) ATTN: Code 461 ATTN: Research Reference Center 70 The Hydrographer, U. S. NavyHydrographic Office Washington 25, D. C. 48 Commanding General ATTN: Code 4100 Army Medical Research & Development Command Main Navy Building, Washington 25, D. C. 71 Chief, Bureau of Ships ATTN: Neuropsychiatry & Psychophysiology Department of the Navy, Washington 25, D. C. Research Branch ATTN: Code 690 49 Commanding Officer, Ordnance Weapons Command 72-73 Director, U. S. Naval Research Laboratory Rock Island, Illinois Washington 25, D. C. ATTN: ORDOW-GN ATTN: Code 2027 50-53 Director, U. S. Army Engineer 74 Commanding Officer, U. S. Navy Ordnance Laboratory 50-53 Director, U. S. Army Engineer Research & Development Laboratoriesorona, ornia Fort Belvoir, Virginia ATTN: Library (50) ATTN: Chief, Topographic Engineer Department 75 Commanding Officer & Director (51-52) ATTN: Chief, Electrical Engineering Department U. S. Navy Electronics Laboratory (53) ATTN: Technical Documents Center San Diego 52, California ATTN: Library 54 Commandant, U. S. Army War College Carlisle Barracks, Pennsylvania 76-77 Department of the Air Force, Headquarters, USAF ATTN: Library Washington 25, D. C. ATTN: AFOIN-1B1 55 Commandant, U. S. Army Command & General Staff College 78 Commander in Chief, Headquarters Fort Leavenworth, Kansas Strategic Air Command, OffuttAir Force Base, Nebraska ATTN: Archives ATTN: DINC 15

Institute of Science and Technology The University of Michigan Distribution List 7, 1 January 1961- Effective Date Copy No. Addressee Copy No. Addressee 79 Aerospace Technical Intelligence Center 122 Chief, U. S. Army Armor Human Research Unit U. S. Air Force Fort Knox, Kentucky Wright-Patterson AFB, Ohio ATTN: Security Officer ATTN: AFCIN-4Bla, Library -~~80-89 ASTIA123 Chief, U. S. Army Infantry HumanResearch Unit 80-89 ASTIA (TIPCR) P. O. Box 2086 Arlington Hall Station, Arlington 12, Virginia Fort Benning, Georgia 90-98 Commander, Wright Air Development Division 124 Chief, USA Leadership Human Research Unit Wright-Patterson AFB, Ohio P. O. Box 2086, Presidio of Monterey, California (90-93) ATTN: WWDE (94) ATTN: WWAD-DIST 125 Chief Scientist, Department of the Army (95) ATTN: WWRDLP-2 Office of the Chief Signal Officer (96-98) ATTN: WWRNOO (Staff Physicist) Research & Development Division, SIGRD-2 Washington 25, D. C. 99-100 Commander, Rome Air Development Center Griffiss AFB, New York 126 Columbia University Electronics Research Laboratories (99) ATTN: RCOIL-2 632 W. 125th Street (100) ATTN: RCWIP-3 Ne ork 27, NewYork New York 27, New York 101-103 Commander, AF Command & Control Development ATTN: Technical Library Division VIA: Commander, Rome Air Development Center Laurence G. Hanscom Field Griffiss AFB, New York Bedford, Massachusetts ATTN: RCKCS ATTN: CCRHA-Stop 36 ~~~104 ~~APGC(PGTRI) ~127 Coordinated Science Laboratory 0 APGCAPGTRIr Fc Be, F d Uniiversity of Illinois, Urbana Illinois Eglin Air Force Base, Florida ATTN: Librarian 105-108 Central Intelligence Agency VIA: ONR Resident Representative 2430 E Street, N. W. 605 S. Goodwin Avenue Washington 25, D. C. Urbana, Illinois ATTN: OCR Mail Room 128 Polytechnic Institute of Brooklyn 109-114 National Aeronautics & Space Administration 55 Johnson Street 1520 H Street, N. W. Brooklyn 1, New York Washington 25, D. C. ATTN: Microwave Research Institute Library 115 Combat Surveillance Project VIA: Air Force Office of Scientific Research Cornell Aeronautical Laboratory, Inc. Washington 25, D. C. Box 168, Arlington 10, Virginia 129 Visibility Laboratory Scripps Institution of Oceanography 116 The RAND Corporation University of California, SanDiego 52, California 1700 Main Street *VIA: ONR Resident Representative, University of California Santa Monica, California Scripps Institution of Oceanography, Bldg. 349 ATTN: Library La Jolla, California 117-118 Cornell Aeronautical Laboratory, Inc. 130 U. S. Army Aviation, Human Research Unit 4455 Genesee Street U. S. Continental Army Command Buffalo 21, New York P. 0. Box 428, Fort Rucker, Alabama ATTN: Librarian 131 Cooley Electronics Laboratory VIA: Bureau of Naval Weapons Representative University of Michigan Research Institute 4455 Genesee Street Ann Arbor, Michigan Buffalo 21, New York ATTN: Director 119-120 Director, Human Resources Research Office 132 U. S. Continental Army Command The George Washington University Liaison Officer, Project MICHIGAN P. 0. Box 3596, Washington 7, D. C. The University of Michigan ~~~~~~ATTN: Library p ~P. O. Box 618, Ann Arbor, Michigan ATTN: Library 133 Commanding Officer, U. S. Army 121 Chief, U. S. Army Air Defense Human Research Unit 133 Commanding Officer, U. S. Army Fort Bliss, Texas Liaison Group, Project MICHIGAN The University of Michigan ATTN: Library P. O. Box 618, Ann Arbor, Michigan 16

AD Div. 30/5 UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- B. Jackson, Philip L. USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- II. Jackson, Philip L. PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 (Rept. no. 2900-218-R) SC-78801 (Rept. no. 2900-218-R) SC-78101 (Contract DA-36-039 SC-78801) Unclassified report (Contract DA-36-039 SC-78801) Unclassified report A temperature disturbance within a large thermocouple junction pro- A temperature disturbance within a large thermocouple junction produces a voltage which decreases with distance from the disturbance. duces a voltage which decreases with distance from the disturbance. With proper junction geometry, resulting voltage residues may be With proper junction geometry, resulting voltage residues may be compared at two or more points on the junction. Positions and mag- compared at two or more points on the junction. Positions and magnitudes of temperature disturbances are thereby determined. Use- Armed Services nitudes of temperature disturbances are thereby determined. Use- Armed Services ful measurement applications result. (over) Technical Information Agency ful measurement applications result. (over) Technical Information Agency UNCLASSIFIED UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- B. Jackson, Philip L. USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- H. Jackson, Philip L. PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- HI. U. S. Army Signal Corps PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- HI. U. S. Army Signal Corps ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 (Rept. no. 2900-218-R) SC-78801 (Rept. no. 2900-218-R) SC-78801 (Contract DA-36-039 SC-78801) Unclassified report (Contract DA-36-039 SC-78801) Unclassified report A temperature disturbance within a large thermocouple junction pro- A temperature disturbance within a large thermocouple junction produces a voltage which decreases with distance from the disturbance. duces a voltage which decreases with distance from the disturbance. With proper junction geometry, resulting voltage residues may be With proper junction geometry, resulting voltage residues may be compared at two or more points on the junction. Positions and mag- compared at two or more points on the junction. Positions and magnitudes of temperature disturbances are thereby determined. Use- Armed Services nitudes of temperature disturbances are thereby determined. Use- Armed Services ful measurement applications result. (over) Technical Information Agency ful measurement applications result. (over) Technical Information Agency UNCLASSIFIED UNCLASSIFIED

AD UNCLASSIFIED AD UNCLASSIFIED DESCRIPTORS DESCRIPTORS Thermocouples Thermocouples Oscillographs Oscillographs Voltage Voltage Temperature Temperature UNCLASSIFIED UNCLASSIFIED AD UNCLASSIFIED AD UNCLASSIFIED DESCRIPTORS DESCRIPTORS Thermocouples Thermocouples Oscillographs Oscillographs Voltage Voltage Temperature Temperature UNCLASSIFIED UNCLASSIFIED

+ AD Div. 30/5 UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- II. Jackson, Philip L. USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- II. Jackson, Philip L. PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 (Rept. no. 2900-218-R) SC-78801 (Rept. no. 2900-218-R) SC-78801 (Contract DA-36-039 SC-78801) Unclassified report (Contract DA-36-039 SC-78801) Unclassified report A temperature disturbance within a large thermocouple junction pro- A temperature disturbance within a large thermocouple junction produces a voltage which decreases with distance from the disturbance. duces a voltage which decreases with distance from the disturbance. With proper junction geometry, resulting voltage residues may be With proper junction geometry, resulting voltage residues may be compared at two or more points on the junction. Positions and mag- compared at two or more points on the junction. Positions and magnitudes of temperature disturbances are thereby determined. Use- Armed Services nitudes of temperature disturbances are thereby determined. Use- Armed Services ful measurement applications result. (over) Technical Information Agency ful measurement applications result. (over) Technical Inormation Agency UNCLASSIFIED UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED AD Div. 30/5 UNCLASSIFIED Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN Institute of Science and Technology, U. of Michigan, Ann Arbor I. Title: Project MICHIGAN USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- II. Jackson, Philip L. USE OF A LARGE THERMOCOUPLE JUNCTION TO LOCATE TEM- II. Jackson, Philip L. PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps PERATURE DISTURBANCES by Philip L. Jackson. Rept. of Proj- III. U. S. Army Signal Corps ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 ect MICHIGAN. Jan 61. 14 p. incl. table, illus. IV. Contract DA-36-039 (Rept. no. 2900-218-R) SC-78801 (Rept. no. 2900-218-R) SC-78801 (Contract DA-36-039 SC-78801) Unclassified report (Contract DA-36-039 SC-78801) Unclassified report A temperature disturbance within a large thermocouple junction pro- A temperature disturbance within a large thermocouple junction produces a voltage which decreases with distance from the disturbance. duces a voltage which decreases with distance from the disturbance. With proper junction geometry, resulting voltage residues may be With proper junction geometry, resulting voltage residues may be compared at two or more points on the junction. Positions and mag- compared at two or more points on the junction. Positions and magnitudes of temperature disturbances are thereby determined. Use- Armed Services nitudes of temperature disturbances are thereby determined. Use- Armed Services ful measurement applications result. (over) Technical Information Agency ful measurement applications result. (over) Technical Information Agency (over) UNCLASSIFIED (over) UNCLASSIFIED ++ ~~~~~+

AD UNCLASSIFIED AD UNCLASSIFIED DESCRIPTORS DESCRIPTORS Thermocouples Thermocouples Oscillographs Oscillographs Voltage Voltage Temperature Temperature UNCLASSIFIED UNCLASSIFIED AD UNCLASSIFIED AD UNCLASSIFIED DESCRIPTORS DESCRIPTORS Thermocouples Thermocouples Oscillographs Oscillographs Voltage Voltage Temperature Temperature UNCLASSIFIED UNCLASSIFIED