Science.gov

Sample records for cold leg thermocouple

  1. Fluid and thermal mixing in a model cold leg and downcomer with loop flow

    SciTech Connect

    Rothe, P.H.; Ackerson, M.F.

    1982-04-01

    This report describes an experimental program of fluid mixing experiments performed at atmospheric pressure in a 1/5-scale transparent model of the cold leg and downcomer of typical Westinghouse and Combustion Engineering pressurized water reactors. The results include transient data from a grid of thermocouples and exensive flow visualization photographs. Substantial mixing of cold injected water with hot primary coolant occurred during many of the tests.

  2. Fluid and thermal mixing in a model cold leg and downcomer with vent-valve flow. [PWR

    SciTech Connect

    Rothe, P.H.; Marscher, W.D.; Block, J.A.

    1982-03-01

    This report describes an experimental program of fluid mixing experiments performed at atmospheric pressure in a 1/5-scale transparent model of the cold leg and downcomer of typical Babcock and Wilcox pressurized water reactors with vent valves. The results include transient data from a grid of thermocouples and extensive flow visualization photographs. Substantial mixing of cold injected water with hot primary coolant occurred during many of the tests.

  3. Transient cooldown in a model cold leg and downcomer. [PWR

    SciTech Connect

    Fanning, M.W.; Rothe, P.H.

    1983-05-01

    This report describes an experimental program of fluid mixing experiments performed at atmospheric pressure in a 1/5-scale, transparent model of a cold leg, downcomer, lower plenum, pump simulator and loop seal typical of Westinghouse and Combustion Engineering Pressurized Water Reactor (PWRs). The tests were transient cooldown tests in that they simulated an extreme condition of Small Break Loss of Coolant Accident (SBLOCA) during which cold High Pressure Injection (HPI) fluid is injected into stagnant, hot, primary fluid with complete loss of natural circulation in the loop. Cooldown in this new test series is much slower than in previous tests that did not model the pump simulator and loop seal volumes. For the stagnant loop condition, the dominant buoyancy force diverts cool HPI water to the additional volumes.

  4. Boric acid precipitation following a cold-leg LOCA

    SciTech Connect

    Twogood, F.J. ); Strong, B.R. ); Lew, B.S. ); Kramer, C. )

    1993-01-01

    For a postulated cold-leg loss-of-coolant accident (LOCA) in a pressurized water reactor, borated water from the safety injection and recirculation systems is predicted to flow preferentially around the reactor pressure vessel (RPV) downcomer and out the rupture, bypassing the core. Flow to the core may therefore be limited to just the flow that is required to make up for boil-off in the core and to maintain an equal static head between the downcomer and core regions. Lacking any mixing of dilute injection water in the core, this would result in the accumulation of boron in the core region until saturation concentrations are reached and boric acid begins to precipitate out of solution. Boric acid precipitation is undesirable because it may interfere with long-term core cooling. Without a reliable estimate of reflux condensation, this time to precipitation establishes the minimum time for the initiation of hot-leg recirculation to flush the core and terminate boric acid concentration. This analysis estimates the boric acid concentration over time for the postulated conditions of a cold-leg LOCA in San Onofre nuclear generating station unit 1, including the explicit incorporation of the stored heat release from the RPV and structures discussed in a companion paper. Earlier analyses assumed that the RPV stored energy was released during the safety injection phase immediately after the LOCA. Recent analyses showed that a significant portion of this stored energy is released into the coolant after core safety injection and needs to be explicitly addressed.

  5. Repeating thermocouple

    SciTech Connect

    Falk, R. A.

    1985-06-04

    Disclosed herein is a repeating use thermocouple assembly and method of making the same in which a cavity adjacent the tip of the thermocouple is filled with a thermosetting foundry sand and baked in place to provide support for the thermocouple tube without causing stresses during use which could cause breakage of the thermocouple tube.

  6. Flow visualization during transient cooldown in a model PWR cold leg and downcomer

    SciTech Connect

    Rothe, P.H.; Valenzuela, J.A.

    1985-02-01

    This report documents flow visualization studies performed in a 1/5 scale model of the cold leg and downcomer typical of Westinghouse or Combustion Engineering pressurized water reactors which have a horizontal cold leg. Tests were performed with stagnant loop flow and prototypical HPI flow (Froude number F/sub CL/ = 0.04). In addition to photographs and movies illustrating phenomena and mechanistic descriptions of the behavior, the results include transient velocity profiles in the cold leg and downcomer, HPI buoyant jet entrainment rates and flow split ratios, and transient density profiles in the cold leg. This study will help to clarify the detailed mixing phenomena that are relevant to the thermal-hydraulic aspects of the Pressurized Thermal Shock concern.

  7. Thermocouple shield

    SciTech Connect

    Ripley, Edward B.

    2009-11-24

    A thermocouple shield for use in radio frequency fields. In some embodiments the shield includes an electrically conductive tube that houses a standard thermocouple having a thermocouple junction. The electrically conductive tube protects the thermocouple from damage by an RF (including microwave) field and mitigates erroneous temperature readings due to the microwave or RF field. The thermocouple may be surrounded by a ceramic sheath to further protect the thermocouple. The ceramic sheath is generally formed from a material that is transparent to the wavelength of the microwave or RF energy. The microwave transparency property precludes heating of the ceramic sheath due to microwave coupling, which could affect the accuracy of temperature measurements. The ceramic sheath material is typically an electrically insulating material. The electrically insulative properties of the ceramic sheath help avert electrical arcing, which could damage the thermocouple junction. The electrically conductive tube is generally disposed around the thermocouple junction and disposed around at least a portion of the ceramic sheath. The concepts of the thermocouple shield may be incorporated into an integrated shielded thermocouple assembly.

  8. High temperature, oxidation resistant noble metal-Al alloy thermocouple

    NASA Technical Reports Server (NTRS)

    Smialek, James L. (Inventor); Gedwill, Michael G. (Inventor)

    1994-01-01

    A thermocouple is disclosed. The thermocouple is comprised of an electropositive leg formed of a noble metal-Al alloy and an electronegative leg electrically joined to form a thermocouple junction. The thermocouple provides for accurate and reproducible measurement of high temperatures (600 - 1300 C) in inert, oxidizing or reducing environments, gases, or vacuum. Furthermore, the thermocouple circumvents the need for expensive, strategic precious metals such as rhodium as a constituent component. Selective oxidation of rhodium is also thereby precluded.

  9. High-Temperature, Oxidation-Resistant Thermocouples

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Gedwill, Michael A.

    1994-01-01

    Aluminum substituted for rhodium, which is scarce and expensive. Electromotive force increases with aluminum content in Pt/Al leg of Pt(Pt/Al) thermocouple. Wires baked longer in aluminizing bed produce larger voltages. Thermocouples containing platinum/aluminum legs used instead of thermocouples of type R in furnaces, heat engines, and chemical reactors. Expecially suited to high-velocity oxidizing environments. Constructed as thin-film sensors on turbine blades and vanes, where pre-oxidation provides insulating film needed between thermocouple legs. Because aluminum content slowly depleted by oxidation, long-term use recommended only where maximum temperature is 1,200 degrees C or less.

  10. Thermocouple assembly

    DOEpatents

    Thermos, Anthony Constantine; Rahal, Fadi Elias

    2002-01-01

    A thermocouple assembly includes a thermocouple; a plurality of lead wires extending from the thermocouple; an insulating jacket extending along and enclosing the plurality of leads; and at least one internally sealed area within the insulating jacket to prevent fluid leakage along and within the insulating jacket. The invention also provides a method of preventing leakage of a fluid along and through an insulating jacket of a thermocouple including the steps of a) attaching a plurality of lead wires to a thermocouple; b) adding a heat sensitive pseudo-wire to extend along the plurality of lead wires; c) enclosing the lead wires and pseudo-wire inside an insulating jacket; d) locally heating axially spaced portions of the insulating jacket to a temperature which melts the pseudo-wire and fuses it with an interior surface of the jacket.

  11. Locating hot and cold-legs in a nuclear powered steam generation system

    DOEpatents

    Ekeroth, D.E.; Corletti, M.M.

    1993-11-16

    A nuclear reactor steam generator includes a reactor vessel for heating water and a steam generator with a pump casing at the lowest point on the steam generator. A cold-leg pipe extends horizontally between the steam generator and the reactor vessel to return water from the steam generator to the reactor vessel. The bottom of the cold-leg pipe is at a first height above the bottom of the reactor vessel. A hot-leg pipe with one end connected to the steam generator and a second end connected to the reactor vessel has a first pipe region extending downwardly from the steam generator to a location between the steam generator and the reactor vessel at which a bottom of the hot-leg pipe is at a second height above the bottom of the reactor vessel. A second region extends from that location in a horizontal direction at the second height to the point at which the hot-leg pipe connects to the reactor vessel. A pump is attached to the casing at a location below the first and second heights and returns water from the steam generator to the reactor vessel over the cold-leg. The first height is greater than the second height and the bottom of the steam generator is at a height above the bottom of the reactor vessel that is greater than the first and second heights. A residual heat recovery pump is below the hot-leg and has an inlet line from the hot-leg that slopes down continuously to the pump inlet. 2 figures.

  12. Locating hot and cold-legs in a nuclear powered steam generation system

    DOEpatents

    Ekeroth, Douglas E.; Corletti, Michael M.

    1993-01-01

    A nuclear reactor steam generator includes a reactor vessel for heating water and a steam generator with a pump casing at the lowest point on the steam generator. A cold-leg pipe extends horizontally between the steam generator and the reactor vessel to return water from the steam generator to the reactor vessel. The bottom of the cold-leg pipe is at a first height above the bottom of the reactor vessel. A hot-leg pipe with one end connected to the steam generator and a second end connected to the reactor vessel has a first pipe region extending downwardly from the steam generator to a location between the steam generator and the reactor vessel at which a bottom of the hot-leg pipe is at a second height above the bottom of the reactor vessel. A second region extends from that location in a horizontal direction at the second height to the point at which the hot-leg pipe connects to the reactor vessel. A pump is attached to the casing at a location below the first and second heights and returns water from the steam generator to the reactor vessel over the cold-leg. The first height is greater than the second height and the bottom of the steam generator is at a height above the bottom of the reactor vessel that is greater than the first and second heights. A residual heat recovery pump is below the hot-leg and has an inlet line from the hot-leg that slopes down continuously to the pump inlet.

  13. RELAP5 Analyses of OECD/NEA ROSA-2 Project Experiments on Intermediate-Break LOCAs at Hot Leg or Cold Leg

    NASA Astrophysics Data System (ADS)

    Takeda, Takeshi; Maruyama, Yu; Watanabe, Tadashi; Nakamura, Hideo

    Experiments simulating PWR intermediate-break loss-of-coolant accidents (IBLOCAs) with 17% break at hot leg or cold leg were conducted in OECD/NEA ROSA-2 Project using the Large Scale Test Facility (LSTF). In the hot leg IBLOCA test, core uncovery started simultaneously with liquid level drop in crossover leg downflow-side before loop seal clearing (LSC) induced by steam condensation on accumulator coolant injected into cold leg. Water remained on upper core plate in upper plenum due to counter-current flow limiting (CCFL) because of significant upward steam flow from the core. In the cold leg IBLOCA test, core dryout took place due to rapid liquid level drop in the core before LSC. Liquid was accumulated in upper plenum, steam generator (SG) U-tube upflow-side and SG inlet plenum before the LSC due to CCFL by high velocity vapor flow, causing enhanced decrease in the core liquid level. The RELAP5/MOD3.2.1.2 post-test analyses of the two LSTF experiments were performed employing critical flow model in the code with a discharge coefficient of 1.0. In the hot leg IBLOCA case, cladding surface temperature of simulated fuel rods was underpredicted due to overprediction of core liquid level after the core uncovery. In the cold leg IBLOCA case, the cladding surface temperature was underpredicted too due to later core uncovery than in the experiment. These may suggest that the code has remaining problems in proper prediction of primary coolant distribution.

  14. Evaluation of thermal mixing data from a model cold leg and downcomer. [PWR

    SciTech Connect

    Rothe, P.H.; Fanning, M.W.

    1982-12-01

    This report describes an evaluation of thermal mixing data obtained in a 1/5-scale, transparent model of the cold leg and downcomer of a Pressurized Water Reactor (PWR). The data are relevant to the phenomenon of fluid and thermal mixing following HPI (High Pressure Injection) of coolant water in a PWR loop. The data are reduced, correlated and compared with theoretically derived values and scaling approaches.

  15. Thermal mixing in a model cold leg and downcomer at low flow rates. [PWR

    SciTech Connect

    Rothe, P.H.; Fanning, M.W.

    1983-03-01

    This report describes an experimental program of fluid-mixing experiments performed at atmospheric pressure in a 1/5-scale, transparent model of a cold leg and downcomer typical of Combustion Engineering and Westinghouse Pressurized Water Reactors (PWRs). The test program simulated steady-state conditions thought to be extreme for small break Loss of Coolant Accidents (LOCAs). Analysis of transient and steady-state temperature records indicates that the cold High-Pressure Injection (HPI) coolant water and the hot primary coolant water are well mixed prior to flowing over the reactor vessel wall.

  16. Instrumentation System Diagnoses a Thermocouple

    NASA Technical Reports Server (NTRS)

    Perotti, Jose; Santiago, Josephine; Mata, Carlos; Vokrot, Peter; Zavala, Carlos; Burns, Bradley

    2008-01-01

    An improved self-validating thermocouple (SVT) instrumentation system not only acquires readings from a thermocouple but is also capable of detecting deterioration and a variety of discrete faults in the thermocouple and its lead wires. Prime examples of detectable discrete faults and deterioration include open- and short-circuit conditions and debonding of the thermocouple junction from the object, the temperature of which one seeks to measure. Debonding is the most common cause of errors in thermocouple measurements, but most prior SVT instrumentation systems have not been capable of detecting debonding. The improved SVT instrumentation system includes power circuitry, a cold-junction compensator, signal-conditioning circuitry, pulse-width-modulation (PWM) thermocouple-excitation circuitry, an analog-to-digital converter (ADC), a digital data processor, and a universal serial bus (USB) interface. The system can operate in any of the following three modes: temperature measurement, thermocouple validation, and bonding/debonding detection. The software running in the processor includes components that implement statistical algorithms to evaluate the state of the thermocouple and the instrumentation system. When the power is first turned on, the user can elect to start a diagnosis/ monitoring sequence, in which the PWM is used to estimate the characteristic times corresponding to the correct configuration. The user also has the option of using previous diagnostic values, which are stored in an electrically erasable, programmable read-only memory so that they are available every time the power is turned on.

  17. SPACE code simulation of cold leg small break LOCA in the ATLAS integral test

    SciTech Connect

    Kim, B. J.; Kim, H. T.; Kim, J.; Kim, K. D.

    2012-07-01

    SPACE code is a system analysis code for pressurized water reactors. This code uses a two-fluid and three-field model. For a few years, intensive validations have been performed to secure the prediction accuracy of models and correlations for two-phase flow and heat transfer. Recently, the code version 1.0 was released. This study is to see how well SPACE code predicts thermal hydraulic phenomena of an integral effect test. The target experiment is a cold leg small break LOCA in the ATLAS facility, which has the same two-loop features as APR1400. Predicted parameters were compared with experimental observations. (authors)

  18. Theory and performance of plated thermocouples.

    NASA Technical Reports Server (NTRS)

    Pesko, R. N.; Ash, R. L.; Cupschalk, S. G.; Germain, E. F.

    1972-01-01

    A theory has been developed to describe the performance of thermocouples which have been formed by electroplating portions of one thermoelectric material with another. The electroplated leg of the thermocouple was modeled as a collection of infinitesimally small homogeneous thermocouples connected in series. Experiments were performed using several combinations of Constantan wire sizes and copper plating thicknesses. A transient method was used to develop the thermoelectric calibrations, and the theory was found to be in quite good agreement with the experiments. In addition, data gathered in a Soviet experiment were also found to be in close agreement with the theory.

  19. A mixing model for transient cooldown in a reactor cold leg and downcomer under stagnant loop flow

    SciTech Connect

    Oh, S.; Sun, B.K.M.; Sursock, J.P.

    1983-07-01

    The mixing of the high pressure coolant injected into a reactor cold leg pipe and the water in the reactor loop causes the temperature of water in the cold leg and the downcomer annulus to decrease. The transient cooldown of the water in the downcomer adjacent to the vessel wall is an important factor in determining thermal stress in the vessel. An analytical model has been developed to describe the phenomena of mixing between the coolant and the hot water in the cold leg and the downcomer for the condition of stagnant loop flow. The model divides the volume of the cold leg and the downcomer into several segments based on the understanding of the phenomenon and the governing physical mechanisms associated with them. In each segmented volume, a first-order ordinary differential equation is used along with appropriate mixing correlations to characterize the mass and energy balances. By satisfying the boundary conditions at the conjunctions of the volumes, the differential equations are solved simultaneously to yield the transient cooldown history of the water in each volume. The model predictions are in agreement with data obtained from the EPRI/CREARE 1/5 scale model facility and the EPRI/SAI rectangular geometry fullheight facility.

  20. Transit time of mixed high pressure injection water and primary loop water in pressurized water reactor cold legs

    SciTech Connect

    Sun, B.H.; Oh, S.; Rothe, P.H.

    1984-03-01

    During an overcooling transient in a pressurized water reactor, cold water from the high pressure injection (HPI) mixes with the hot primary coolant in the cold leg. The transit time is a gauge for the assessment of the time and the velocity of the mixed flow that passes through the cold leg to the downcomer. Existing data from mixing tests at the Electric Power Research Institute (EPRI)/CREARE and EPRI/SAI facilities are analyzed. By means of models for HPI jet entrainment as well as the propagation of a gravity current, dimensionless correlations have been developed for the transit time and cold water front velocity at stagnant loop flow conditions. Based on this transit time correlation for stagnant loop flow and the limiting condition for large loop flow, a general correlation has been developed to account for the loop flow effect on transit time. These correlations unify a wide range of data obtained from five geometrically different test sections with two fluids (pure water and saline solution). In addition to the geometric factors, the governing dimensionless parameters for the transit time are the HPI jet Froude number, the Froude number for the cold-leg channel, and the ratio of loop flow to HPI flow.

  1. Possible quantum phase manipulation of a two-leg ladder in mixed-dimensional fermionic cold atoms

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Min; Irwin, Kyle; Tsai, Shan-Wen

    2013-03-01

    The recent realization of mixed-dimensional systems of cold atoms has attracted much attention from both experimentalists and theorists. In this article we investigate a two-species Fermi atom mixture: one species of atom exists in two hyperfine states and is confined to move in a two-leg ladder, interacting with an on-site interaction, and the other moves freely in a two-dimensional square lattice that contains the two-leg ladder. The two species of atoms interact via an on-site interaction on the ladder. In the limit of weak interspecies interactions, the two-dimensional gas can be integrated out, leading to an effective long-range mediated interaction in the ladder, generated by the on-site interspecies interaction. We show that the form of the mediated interaction can be controlled by the density of the two-dimensional gas and that it enhances the charge-density wave instability in the two-leg ladder after the renormalization-group transformation. Parametrizing the phase diagram with various experimentally controllable quantities, we discuss the possible tuning of the macroscopic quantum many-body phases of the two-leg ladder in this mixed-dimensional fermionic cold atom system.

  2. Self-Validating Thermocouple

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M. (Inventor); Mata, Carlos T. (Inventor); Santiago, Josephine B. (Inventor); Vokrot, Peter (Inventor); Zavala, Carlos E. (Inventor); Burns, Bradley M. (Inventor)

    2010-01-01

    Self-Validating Thermocouple (SVT) Systems capable of detecting sensor probe open circuits, short circuits, and unnoticeable faults such as a probe debonding and probe degradation are useful in the measurement of temperatures. SVT Systems provide such capabilities by incorporating a heating or excitation element into the measuring junction of the thermocouple. By heating the measuring junction and observing the decay time for the detected DC voltage signal, it is possible to indicate whether the thermocouple is bonded or debonded. A change in the thermal transfer function of the thermocouple system causes a change in the rise and decay times of the thermocouple output. Incorporation of the excitation element does not interfere with normal thermocouple operation, thus further allowing traditional validation procedures as well.

  3. COMMIX-1A analysis of fluid and thermal mixing in a model cold leg and downcomer of a PWR

    SciTech Connect

    Chen, B.C.J.; Cha, B.K.; Miao, C.C.; Sha, W.T.; Kim, J.H.; Sun, B.K.H.

    1983-01-01

    The issue of thermal shock of a PWR pressure vessel has been under considerable attention recently. A number of experimental as well as analytical studies have been performed to investigate the effect of the thermal transient on the pressure vessel due to the high pressure injection (HPI) of the cold fluid into the cold leg. This process has been called Pressurized Thermal Shock (PTS). This paper is an analytical study of PTS by using COMMIX-1A. Experimental investigations were performed at CREARE and SAI. In the CREARE experiment, a 1/5 scale model was set up to simulate a cold leg and downcomer of a PWR. Tests with several different ratios of hot loop flow versus cold HPI flow were performed to study the effect of the flow ratio on the fluid and thermal mixing process in the system, especially in the downcomer region. Analytical investigations also proceeded in parallel with the experiments. Quite a few analytical investigations were performed with the COMMIX-1A code. However, in this version of COMMIX, the effect of the numerical diffusion was not addressed.

  4. HIGH TEMPERATURE THERMOCOUPLE

    DOEpatents

    Eshayu, A.M.

    1963-02-12

    This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact. The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream. (AEC)

  5. Thin film ceramic thermocouples

    NASA Technical Reports Server (NTRS)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  6. Modern Thermocouple Experiment.

    ERIC Educational Resources Information Center

    Chang, K. N.; And Others

    1978-01-01

    Describes a thermocouple circuit used to measure Joule heating as well as Peltier heating and cooling for a copper-Constantan metallic junction. Shows how the Seebeck effect from a thermocouple can monitor the temperature condition of a junction with regard to input power and Peltier effect. (Author/GA)

  7. THERMOCOUPLE READOUT INSTRUMENT

    EPA Science Inventory

    An electronic circuit has been developed which acts as an electronic ice bath for chromel-constantan thermocouples. The electronic ice bath is accurate to within plus or minus 0.2C from -25C to +50C. Simultaneously, the thermocouple output is scaled and linearized such that the t...

  8. COMMIX-1A analysis of fluid and thermal mixing in a model cold leg and downcomer of a PWR

    SciTech Connect

    Chen, B.C.J.; Cha, B.K.; Sha, W.T.

    1984-06-01

    Fluid and thermal mixing in a model cold leg and downcomer of a PWR was analyzed using COMMIX-1A. The present analysis differs from previous analyses reported in EPRI NP-3321 in three major aspects. First, extremely fine meshes were used to minimize numerical diffusion in the analysis. Second, one-equation (k) turbulence model was used to better model the turbulent flow. Third, curved surfaces were modeled by several slanted planes to better represent the geometries. By using these improvements, CREARE 1/5-scale test No. 51 was reanalyzed. Significant improvements were achieved in the comparisons between the COMMIX-1A calculations and the experimental data.

  9. Multiwire thermocouples: Frequency response

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Fralick, G. C.

    1994-01-01

    Experimental measurements are made with a novel two wire thermocouple. Signals from two wires of unequal diameters are recorded from the thermocouple suspended in constant flow with a periodic temperature fluctuation. It is demonstrated that the reconstructed signal from the two wire thermocouple requires no compensation for omega less than or equal to 2 omega(sub 1) where omega is the natural frequency of the smaller wire. A compensation factor is recommended for larger frequencies omega greater than 2 omega(sub 1). Theory and experimental measurements are compared with a novel three wire thermocouple. Signals from three wires of unequal diameters are recorded from the thermocouple suspended in constant flow with a periodic temperature fluctuation. It is demonstrated that the reconstructed signal from the three wire thermocouple requires no compensation for omega less than or equal to 5 omega(sub 1) where omega (sub 1) is the natural frequency of the smaller wire. The latter result represents a significant improvement compared to previous work with two wire thermocouples. A correction factor has also been derived to account for wires of arbitrary diameter. Measurements are recorded for multiwire thermocouples consisting of either two or three wires of unequal diameters. Signals from the multiwire probe are recorded for a reversing gas flow with a periodic temperature fluctuation. It is demonstrated that the reconstructed signal from the multiwire thermocouple requires no compensation provided omega/omega(sub 1) is less than 2.3 for two wires or omega/omega(sub 1) is less than 3.6 for three wires where omega(sub 1) is the natural frequency of the smaller wire based on the maximum gas velocity. The latter results were possible provided Fourier transformed data were used and knowledge of the gas velocity is available.

  10. Spring loaded thermocouple module

    DOEpatents

    McKelvey, Thomas E.; Guarnieri, Joseph J.

    1985-01-01

    A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

  11. Spring loaded thermocouple module

    DOEpatents

    McKelvey, T.E.; Guarnieri, J.J.

    1984-03-13

    A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

  12. ITS-90 Thermocouple Database

    National Institute of Standards and Technology Data Gateway

    SRD 60 NIST ITS-90 Thermocouple Database (Web, free access)   Web version of Standard Reference Database 60 and NIST Monograph 175. The database gives temperature -- electromotive force (emf) reference functions and tables for the letter-designated thermocouple types B, E, J, K, N, R, S and T. These reference functions have been adopted as standards by the American Society for Testing and Materials (ASTM) and the International Electrotechnical Commission (IEC).

  13. Microminiature thermocouple monitors own installation

    NASA Technical Reports Server (NTRS)

    Garrett, A. J.; Sellers, J. P., Jr.

    1966-01-01

    Microminiature thermocouple makes precision gas sidewall temperature readings inside large thrust chambers. It is installed by a technique whereby the sensor monitors its own installation to insure against thermal damage to the thermocouple and ensure minimum disturbance to chamber surfaces.

  14. Thermocouple-Signal-Conditioning Circuit

    NASA Technical Reports Server (NTRS)

    Simon, Richard A.

    1991-01-01

    Thermocouple-signal-conditioning circuit acting in conjunction with thermocouple, exhibits electrical behavior of voltage in series with resistance. Combination part of input bridge circuit of controller. Circuit configured for either of two specific applications by selection of alternative resistances and supply voltages. Includes alarm circuit detecting open circuit in thermocouple and provides off-scale output to signal malfunctions.

  15. Advanced thin film thermocouples

    NASA Astrophysics Data System (ADS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-10-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  16. Program Processes Thermocouple Readings

    NASA Technical Reports Server (NTRS)

    Quave, Christine A.; Nail, William, III

    1995-01-01

    Digital Signal Processor for Thermocouples (DART) computer program implements precise and fast method of converting voltage to temperature for large-temperature-range thermocouple applications. Written using LabVIEW software. DART available only as object code for use on Macintosh II FX or higher-series computers running System 7.0 or later and IBM PC-series and compatible computers running Microsoft Windows 3.1. Macintosh version of DART (SSC-00032) requires LabVIEW 2.2.1 or 3.0 for execution. IBM PC version (SSC-00031) requires LabVIEW 3.0 for Windows 3.1. LabVIEW software product of National Instruments and not included with program.

  17. Advanced thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-01-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  18. Three-dimensional analysis of thermal and fluid mixing in cold leg and downcomer of PWR geometries

    SciTech Connect

    Lyczkowski, R.W.; Miao, C.C.; Domanus, H.M.; Hull, J.R.; Sha, W.T.; Schmitt, R.C.

    1983-12-01

    This report describes the three-dimensional transient and steady-state computations using the COMMIX-1A computer code for the analysis of six (6) 1/5-scale thermal and fluid mixing experiments conducted at Creare, Inc. under EPRI sponsorship. The tests chosen for analyses emphasized the effects of vent valve flow, cold leg and high pressure injection (HPI) coolant flow rates, and HPI location and geometry. The COMMIX-1A computations will provide fluid temperatures and velocities in the belt-line region of the downcomer for assessment of boundary conditions for thermal stress analysis in the vessel walls. A realistic prediction for thermal and fluid mixing significantly helps establish what overcooling transients can lead to in pressurized thermal shock (PTS) events. Sample three-dimensional steady-state computations are presented for three (3) generic full-scale pressurized water reactors (PWR's) typical of Westinghouse (W), Combustion Engineering (CE), and Babcock and Wilcox (B and W) configurations as part of the code assessment.

  19. Assessment of RELAP/MOD3 using BETHSY 6.2TC 6-inch cold leg side break comparative test

    SciTech Connect

    Chung, Young-Jong; Jeong, Jae-Jun; Chang, Won-Pyo; Kim, Dong-Su

    1996-10-01

    This report presents the results of the RELAP5/MOD3 Version 7j assessment on BETHSY 6.2TC. BETHSY 6.2TC test corresponding to a six inch cold leg break LOCA of the Pressurizer Water Reactor(PWR). The primary objective of the test was to provide reference data of two facilities of different scales (BETHSY and LSTF facility). On the other hand, the present calculation aims at analysis of RELAP5/N4OD3 capability on the small break LOCA simulation, The results of calculation have shown that the RELAP5/MOD3 reasonably predicts occurrences as well as trends of the major phenomena such as primary pressure, timing of loop seal clearing, liquid hold up, etc. However, some disagreements also have been found in the predictions of loop seal clearing, collapsed core water level after loop seal clearing, and accumulator injection behaviors. For better understanding of discrepancies in same predictions, several sensitivity calculations have been performed as well. These include the changes of two-phase discharge coefficient at the break junction and some corrections of the interphase drag term. As result, change of a single parameter has not improved the overall predictions and it has been found that the interphase drag model has still large uncertainties.

  20. Pressurized thermal shock: TEMPEST computer code simulation of thermal mixing in the cold leg and downcomer of a pressurized water reactor. [Creare 61 and 64

    SciTech Connect

    Eyler, L.L.; Trent, D.S.

    1984-04-01

    The TEMPEST computer program was used to simulate fluid and thermal mixing in the cold leg and downcomer of a pressurized water reactor under emergency core cooling high-pressure injection (HPI), which is of concern to the pressurized thermal shock (PTS) problem. Application of the code was made in performing an analysis simulation of a full-scale Westinghouse three-loop plant design cold leg and downcomer. Verification/assessment of the code was performed and analysis procedures developed using data from Creare 1/5-scale experimental tests. Results of three simulations are presented. The first is a no-loop-flow case with high-velocity, low-negative-buoyancy HPI in a 1/5-scale model of a cold leg and downcomer. The second is a no-loop-flow case with low-velocity, high-negative density (modeled with salt water) injection in a 1/5-scale model. Comparison of TEMPEST code predictions with experimental data for these two cases show good agreement. The third simulation is a three-dimensional model of one loop of a full size Westinghouse three-loop plant design. Included in this latter simulation are loop components extending from the steam generator to the reactor vessel and a one-third sector of the vessel downcomer and lower plenum. No data were available for this case. For the Westinghouse plant simulation, thermally coupled conduction heat transfer in structural materials is included. The cold leg pipe and fluid mixing volumes of the primary pump, the stillwell, and the riser to the steam generator are included in the model. In the reactor vessel, the thermal shield, pressure vessel cladding, and pressure vessel wall are thermally coupled to the fluid and thermal mixing in the downcomer. The inlet plenum mixing volume is included in the model. A 10-min (real time) transient beginning at the initiation of HPI is computed to determine temperatures at the beltline of the pressure vessel wall.

  1. Thermocouple homogeneity scanning

    NASA Astrophysics Data System (ADS)

    Webster, E.; White, D. R.

    2015-02-01

    The inhomogeneities within a thermocouple influence the measured temperature and contribute the largest component to uncertainty. Currently there is no accepted best practice for measuring the inhomogeneities or for forecasting their effects on real-world measurements. The aim of this paper is to provide guidance on the design and performance assessment of thermocouple inhomogeneity scanners by characterizing the qualitative performance of the various designs reported in the literature, and developing a quantitative measure of scanner resolution. Numerical simulations incorporating Fourier transforms and convolutions are used to gauge the levels of attenuation and distortion present in single- and double-gradient scanners. Single-gradient scanners are found to be far superior to double-gradient scanners, which are unsuitable for quantitative measurements due to their blindness to inhomogeneities at many spatial frequencies and severe attenuation of signals at other frequencies. It is recommended that the standard deviation of the temperature gradient within the scanner is used as a measure of the scanner resolution and spatial bandwidth. Recommendations for the design of scanners are presented, and include advice on the basic design of scanners, the media employed, operating temperature, scan rates, construction of survey probes, data processing, gradient symmetry, and the spatial resolution required for research and calibration applications.

  2. Method for forming a thermocouple

    DOEpatents

    Metz, Hugh J.

    1979-01-01

    A method is provided for producing a fast response, insulated junction thermocouple having a uniform diameter outer sheath in the region of the measuring junction. One step is added to the usual thermocouple fabrication process that consists in expanding the thermocouple sheath following the insulation removal step. This makes it possible to swage the sheath back to the original diameter and compact the insulation to the desired high density in the final fabrication step.

  3. Advanced Microscopic Integrated Thermocouple Arrays

    NASA Technical Reports Server (NTRS)

    Pettigrew, Penny J.

    1999-01-01

    The purpose of this research is to develop and refine a technique for making microscopic thermocouple arrays for use in measuring the temperature gradient across a solid-liquid interface during the solidification process. Current thermocouple technology does not allow for real-time measurements across the interface due to the prohibitive size of available thermocouples. Microscopic thermocouple arrays will offer a much greater accuracy and resolution of temperature measurements across the solid-liquid interface which will lead to a better characterization of the solidification process and interface reaction which affect the properties of the resulting material.

  4. Cobra Probes Containing Replaceable Thermocouples

    NASA Technical Reports Server (NTRS)

    Jones, John; Redding, Adam

    2007-01-01

    A modification of the basic design of cobra probes provides for relatively easy replacement of broken thermocouples. Cobra probes are standard tube-type pressure probes that may also contain thermocouples and that are routinely used in wind tunnels and aeronautical hardware. They are so named because in side views, they resemble a cobra poised to attack. Heretofore, there has been no easy way to replace a broken thermocouple in a cobra probe: instead, it has been necessary to break the probe apart and then rebuild it, typically at a cost between $2,000 and $4,000 (2004 prices). The modified design makes it possible to replace the thermocouple, in minimal time and at relatively low cost, by inserting new thermocouple wire in a tube.

  5. Annealing Increases Stability Of Iridium Thermocouples

    NASA Technical Reports Server (NTRS)

    Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.; Ahmed, Shaffiq

    1989-01-01

    Metallurgical studies carried out on samples of iridium versus iridium/40-percent rhodium thermocouples in condition received from manufacturer. Metallurgical studies included x-ray, macroscopic, resistance, and metallographic studies. Revealed large amount of internal stress caused by cold-working during manufacturing, and large number of segregations and inhomogeneities. Samples annealed in furnace at temperatures from 1,000 to 2,000 degree C for intervals up to 1 h to study effects of heat treatment. Wire annealed by this procedure found to be ductile.

  6. High-temperature thermocouples and related methods

    DOEpatents

    Rempe, Joy L.; Knudson, Darrell L.; Condie, Keith G.; Wilkins, S. Curt

    2011-01-18

    A high-temperature thermocouple and methods for fabricating a thermocouple capable of long-term operation in high-temperature, hostile environments without significant signal degradation or shortened thermocouple lifetime due to heat induced brittleness.

  7. A study of thermal stratification in the cold legs during the subcooled blowdown phase of a loss of coolant accident in the OSU APEX thermal hydraulic testing facility.

    SciTech Connect

    Wachs, D. M.

    1998-11-04

    Thermal stratification, which has been linked to the occurrence of pressurized thermal shock (PTS), is observed to occur during the early stages of simulated loss of coolant accidents (LOCAS) in the Oregon State University Advanced Plant Experiment (OSU APEX) Thermal Hydraulic Test Facility. The OSU APEX Test Facility is a scaled model of the Westinghouse AP600 nuclear power plant. Analysis of the OSU APEX facility data has allowed the determination of an onset criteria for thermal stratification and has provided support for the postulated mechanisms leading to thermal stratification. CFX 4.1, a computational fluid dynamics code, was used to generate a model of the cold legs and the downcomer that described the phenomena occurring within them. Some mixing phenomena were predicted that lead to non-uniformity between the two cold legs attached to the steam generator on the side of the facility containing the Passive Residual Heat Removal (PRHR) injection system. The stratification was found to be two phase and unlikely to be a factor in PTS.

  8. Using an IIST 1% Cold-Leg SBLOCA Experiment with Passive Safety Injection to Assess the RELAP5/MOD3.2 Code

    SciTech Connect

    Lee, C.-H.; Huang, I-M.; Chang, C.-J

    2001-08-15

    The thermal-hydraulic behavior of a postulated 1% cold-leg break loss-of-coolant accident (LOCA) in a pressurized water reactor system was investigated experimentally by the three-loop Institute of Nuclear Energy Research (INER) Integral System Test (IIST) facility with the passive core cooling system (PCCS) and numerically by the RELAP5/MOD3.2 computer code. The PCCS of the IIST facility includes three core makeup tanks (CMTs), three accumulators, and a four-stage automatic depressurization system. The aim of this research is to study the performance of the CMTs with the actuation of the ADS during a small-break LOCA. The experimental results show that the IIST PCCS has the capability to maintain long-term cooling under a postulated 1% cold-leg break LOCA. The comparison of the RELAP5/MOD3.2 simulation against the experimental data shows good agreement in major thermal-hydraulic phenomena in the reactor coolant system, but the prediction of the asymmetric behavior for the three CMTs during a gravity drain period is inadequate.

  9. Restless Legs

    MedlinePlus

    Restless legs syndrome (RLS) causes a powerful urge to move your legs. Your legs become uncomfortable when you are lying down or sitting. ... your legs feel better, but not for long. RLS can make it hard to fall asleep and ...

  10. Blackbody comparator for thermocouple calibration

    SciTech Connect

    Ojanen, M.; Hahtela, O. M.; Heinonen, M.

    2013-09-11

    MIKES is developing a measurement set-up for calibrating thermocouples in the temperature range 960 °C - 1500 °C. The calibration method is based on direct comparison of thermocouples and radiation thermometers. We have designed a graphite blackbody comparator cell, which is operated in a horizontal single-zone tube furnace. The cell includes two blackbody cavities for radiation temperature measurements. The cavities have openings on opposite sides of the cell, allowing simultaneous measurement with two radiation thermometers. The design of the comparator allows three thermocouples to be calibrated simultaneously. The thermocouples to be calibrated are inserted in thermometer wells around one of the measurement cavities. We characterize the blackbody comparator in terms of repeatability, temperature distribution and emissivity. Finally, we validate the uncertainty analysis by comparing calibration results obtained for type B and S thermocouples to the calibration results reported by Technical Research Institute of Sweden (SP), and MIKES. The agreement in the temperature range 1000 °C - 1500 °C is within 0.90 °C, the average deviation being 0.17 °C.

  11. Temperature monitoring device and thermocouple assembly therefor

    DOEpatents

    Grimm, Noel P.; Bauer, Frank I.; Bengel, Thomas G.; Kothmann, Richard E.; Mavretish, Robert S.; Miller, Phillip E.; Nath, Raymond J.; Salton, Robert B.

    1991-01-01

    A temperature monitoring device for measuring the temperature at a surface of a body, composed of: at least one first thermocouple and a second thermocouple; support members supporting the thermocouples for placing the first thermocouple in contact with the body surface and for maintaining the second thermocouple at a defined spacing from the body surface; and a calculating circuit connected to the thermocouples for receiving individual signals each representative of the temperature reading produced by a respective one of the first and second thermocouples and for producing a corrected temperature signal having a value which represents the temperature of the body surface and is a function of the difference between the temperature reading produced by the first thermocouple and a selected fraction of the temperature reading provided by the second thermocouple.

  12. Heat penetration and thermocouple location in home canning

    PubMed Central

    Etzel, Mark R; Willmore, Paola; Ingham, Barbara H

    2015-01-01

    We processed applesauce, tomato juice, and cranberries in pint jars in a boiling water canner to test thermal processing theories against home canning of high-acid foods. For each product, thermocouples were placed at various heights in the jar. Values for fh (heating), fcl (cooling), and F82.2°C (lethality) were determined for each thermocouple location, and did not depend substantially on thermocouple location in accordance with heat transfer theory. There was a cold spot in the jar, but the cold spot during heating became the hot spot during cooling. During heating, the geometric center was the last to heat, and remained coldest the longest, but during coooling, it was also the last to cool, and remained hottest the longest. The net effect was that calculated lethality in home canning was not affected by thermocouple location. Most of the lethality during home canning occurred during air cooling, making cooling of home canned foods of great importance. Calculated lethality was far greater than the required 5-log reduction of spores in tomato juice and vegetative cells in cranberries, suggesting a wide margin of safety for approved home-canning processes for high-acid foods. PMID:25649758

  13. Heat penetration and thermocouple location in home canning.

    PubMed

    Etzel, Mark R; Willmore, Paola; Ingham, Barbara H

    2015-01-01

    We processed applesauce, tomato juice, and cranberries in pint jars in a boiling water canner to test thermal processing theories against home canning of high-acid foods. For each product, thermocouples were placed at various heights in the jar. Values for f h (heating), f cl (cooling), and F 82.2°C (lethality) were determined for each thermocouple location, and did not depend substantially on thermocouple location in accordance with heat transfer theory. There was a cold spot in the jar, but the cold spot during heating became the hot spot during cooling. During heating, the geometric center was the last to heat, and remained coldest the longest, but during coooling, it was also the last to cool, and remained hottest the longest. The net effect was that calculated lethality in home canning was not affected by thermocouple location. Most of the lethality during home canning occurred during air cooling, making cooling of home canned foods of great importance. Calculated lethality was far greater than the required 5-log reduction of spores in tomato juice and vegetative cells in cranberries, suggesting a wide margin of safety for approved home-canning processes for high-acid foods. PMID:25649758

  14. ASTM standards on thermocouples, 2nd edition

    SciTech Connect

    Not Available

    1986-01-01

    This edition has been expanded to include sixteen selected ASTM methods and practices on thermocouples. It also contains a Temperature Electromotive Force (EMF) Table for the NICROSIL-NISIL Thermocouple System.

  15. Multiwire Thermocouples in Reversing Flow

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Fralick, G. C.

    1995-01-01

    Measurements are recorded for multiwire thermocouples consisting of either two or three wires of unequal diameters. Signals from the multiwire probe are recorded for a reversing gas flow with both a periodic temperature and time constant fluctuation. It is demonstrated that the reconstructed signal from the multiwire thermocouple requires no compensation provided omega/omega(sub 1) less than 2.3 for two wires or omega/omega(sub 1) less than 3.6 for three wires where omega(sub 1) (= 2(pi)f) is the natural frequency of the smaller wire based on the maximum gas velocity. The latter results were possible provided Fourier transformed data from the wires were used and knowledge of the gas velocity phase angle was available.

  16. Correction for Thermal EMFs in Thermocouple Feedthroughs

    NASA Technical Reports Server (NTRS)

    Ziemke, Robert A.

    2006-01-01

    A straightforward measurement technique provides for correction of thermal-electromotive-force (thermal-EMF) errors introduced by temperature gradients along the pins of non-thermocouple-alloy hermetic feedthrough connectors for thermocouple extension wires that must pass through bulkheads. This technique is an alternative to the traditional technique in which the thermal-EMF errors are eliminated by use of custom-made multipin hermetic feedthrough connectors that contain pins made of the same alloys as those of the thermocouple extension wires. One disadvantage of the traditional technique is that it is expensive and time-consuming to fabricate multipin custom thermocouple connectors. In addition, the thermocouple-alloy pins in these connectors tend to corrode easily and/or tend to be less rugged compared to the non-thermocouple-alloy pins of ordinary connectors. As the number of thermocouples (and thus pins) is increased in a given setup, the magnitude of these disadvantages increases accordingly. The present technique is implemented by means of a little additional hardware and software, the cost of which is more than offset by the savings incurred through the use of ordinary instead of thermocouple connectors. The figure schematically depicts a typical measurement setup to which the technique is applied. The additional hardware includes an isothermal block (made of copper) instrumented with a reference thermocouple and a compensation thermocouple. The reference thermocouple is connected to an external data-acquisition system (DAS) through a two-pin thermocouple-alloy hermetic feedthrough connector, but this is the only such connector in the apparatus. The compensation thermocouple is connected to the DAS through two pins of the same ordinary multipin connector that connects the measurement thermocouples to the DAS.

  17. Method for bonding thin film thermocouples to ceramics

    DOEpatents

    Kreider, Kenneth G.

    1993-01-01

    A method is provided for adhering a thin film metal thermocouple to a ceramic substrate used in an environment up to 700 degrees Centigrade, such as at a cylinder of an internal combustion engine. The method includes the steps of: depositing a thin layer of a reactive metal on a clean ceramic substrate; and depositing thin layers of platinum and a platinum-10% rhodium alloy forming the respective legs of the thermocouple on the reactive metal layer. The reactive metal layer serves as a bond coat between the thin noble metal thermocouple layers and the ceramic substrate. The thin layers of noble metal are in the range of 1-4 micrometers thick. Preferably, the ceramic substrate is selected from the group consisting of alumina and partially stabilized zirconia. Preferably, the thin layer of reactive metal is in the range of 0.015-0.030 micrometers (15-30 nanometers) thick. The preferred reactive metal is chromium. Other reactive metals may be titanium or zirconium. The thin layer of reactive metal may be deposited by sputtering in ultra high purity argon in a vacuum of approximately 2 milliTorr (0.3 Pascals).

  18. Simulation of cold leg manifold break and station blackout revised sequences for reduced ECCS (emergency core cooling system) in the N Reactor

    SciTech Connect

    Bolander, M.A.; Chapman, J.C.; Fletcher, C.D.

    1988-02-01

    This report presents analyses of two loss-of-coolant-accident sequences of the N Reactor using the RELAPS/MOD2 computer code. RELAP5/MOD2 is a best estimate, two phase, nonhomogeneous, nonequilibrium, thermal-hydraulic, computer code designed for light water pressurized reactor transient. The N Reactor is a graphite- moderated, pressurized water reactor. The primary coolant is channeled through 1003 horizontal pressure tubes which contain two concentric tubular metallic fuel elements. The two accident sequences simulated were a double-ended guillotine break in the cold leg manifold and a station blackout. Both simulations cover the period beginning with the initiating event, either the break or the loss of ac power, to the stabilization of the core fuel element temperatures. (The station blackout calculation was carried out until the core was quenched.) The discussion presented in this report includes brief descriptions of the N Reactor, of the computer code and specific code modifications for horizontal reflood, and the computer code model used for the simulation. This discussion also presents the results and the analyses of the two calculations.

  19. Probe with integrated heater and thermocouple pack

    DOEpatents

    McCulloch, Reginald W.; Dial, Ralph E.; Finnell, Wilber K. R.

    1988-01-01

    A probe for measuring heat includes an elongate rod fitted within a sheath, and a plurality of annular recesses are formed on the surface of the rod in a spaced-apart relationship to form annular chambers that are resistant to heat flow. A longitudinal bore extends axially into the rod and within the cylinders defined by the annular chambers, and an integrated heater and thermocouple pack is dimensioned to fit within the bore. In construction, the integrated pack includes a plurality of wires disposed in electrical insulation within a sheath and a heater cable. These wires include one common wire and a plurality of thermocouple wires. The common wire is constructed of one type of conductive material while the thermocouple wires are each constructed of two types of materials so that at least one thermocouple junction is formed therein. All of the wires extend the length of the integrated pack and are connected together at their ends. The thermocouple wires are constructed to form thermocouple junctions proximate to each annular chamber for producing electromotive forces corresponding to the temperature of the rod within the annular chambers relative to outside the chambers. In the preferred embodiment, each thermocouple wire forms two thermocouple junctions, one junction being disposed within an annular chamber and the second junction being disposed outside of, but proximate to, the same annular chamber. In one embodiment two thermocouple wires are configured to double the sensitivity of the probe in one region.

  20. Improvement of COBRA-TF for modeling of PWR cold- and hot-legs during reactor transients

    NASA Astrophysics Data System (ADS)

    Salko, Robert K.

    capture of more advanced physics in the coolant-line that can be expected during Loss-of-Coolant Accident. One of the package's benefits is its ability to be used as a platform for future coolant-line model development and implementation, including capturing of the important de-entrainment behavior in reactor hot-legs (steam-binding effect) and flow convection in the upper-plenum region of the vessel.

  1. Probe with integrated heater and thermocouple pack

    SciTech Connect

    McCulloch, Reg W.; Dial, Ralph E.; Finnell, Wilber K. R.

    1990-01-01

    A probe for measuring heat includes an elongate rod fitted within a sheath, and a plurality of annular recesses are formed on the surface of the rod in a spaced-apart relationship to form annular chambers that are resistant to heat flow. A longitudinal bore extends axially into the rod and within the cylinders defined by the annular chambers, and an integrated heater and thermocouple pack is dimensioned to fit within the bore. In construction, the integrated pack includes a plurality of wires disposed in electrical insulation within a sheath and a heater cable. These wires include one common wire and a plurality of thermocuple wires. The common wire is constructed of one type of conductive material while the thermocouple wires are each constructed of two types of materials so that at least one thermocouple junction is formed therein. All of the wires extend the length of the integrated pack and are connected together at their ends. The thermocouple wires are constructed to form thermocouple junctions proximate to each annular chamber for producing electromotive forces corresponding to the temperature of the rod within the annular chambers relative to outside the chambers. In the preferred embodiment, each thermocouple wire forms two thermocouple junctions, one junction being disposed within an annular chamber and the second junction being disposed outside of, but proximate to, the same annular chamber. In one embodiment two thermocouple wires are configured to double the sensitivity of the probe in one region.

  2. NUCLEAR REACTOR SLUG PROVIDED WITH THERMOCOUPLE

    DOEpatents

    Kanne, W.R.

    1958-10-14

    A temperature measuring apparatus is described for use in a reactor. In this invention a cylindrlcal fuel slug is provided with an axial bore in which is disposed a thermocouple. The lead wires extend to a remote indicating device which indicates the temperature in the fuel element measured by the thermocouple.

  3. Probe with integrated heater and thermocouple pack

    SciTech Connect

    McCulloch, R.W.; Dial, R.E.; Finnell, W.F.R.

    1988-02-16

    This patent describes a gamma thermometer probe for detecting heat produced within the thermometer probe. It comprises: an outer elongate thermometer sheath; an elongate rod; annular recesses; a longitudinal bore; and an integrated thermocouple pack. The thermocouple pack comprises: a first type wire, and second type wires. The second type wires comprises: an outer section; and an inner segment.

  4. Attaching Thermocouples by Peening or Crimping

    NASA Technical Reports Server (NTRS)

    Murtland, Kevin; Cox, Robert; Immer, Christopher

    2006-01-01

    Two simple, effective techniques for attaching thermocouples to metal substrates have been devised for high-temperature applications in which attachment by such conventional means as welding, screws, epoxy, or tape would not be effective. The techniques have been used successfully to attach 0.005- in. (0.127-mm)-diameter type-S thermocouples to substrates of niobium alloy C-103 and stainless steel 416 for measuring temperatures up to 2,600 F (1,427 C). The techniques are equally applicable to other thermocouple and substrate materials. In the first technique, illustrated in the upper part of the figure, a hole slightly wider than twice the diameter of one thermocouple wire is drilled in the substrate. The thermocouple is placed in the hole, then the edge of the hole is peened in one or more places by use of a punch (see figure). The deformed material at the edge secures the thermocouple in the hole. In the second technique a hole is drilled as in the first technique, then an annular relief area is machined around the hole, resulting in structure reminiscent of a volcano in a crater. The thermocouple is placed in the hole as in the first technique, then the "volcano" material is either peened by use of a punch or crimped by use of sidecutters to secure the thermocouple in place. This second technique is preferable for very thin thermocouples [wire diameter .0.005 in. (.0.127 mm)] because standard peening poses a greater risk of clipping one or both of the thermocouple wires. These techniques offer the following advantages over prior thermocouple-attachment techniques: . Because these techniques involve drilling of very small holes, they are minimally invasive . an important advantage in that, to a first approximation, the thermal properties of surrounding areas are not appreciably affected. . These techniques do not involve introduction of any material, other than the substrate and thermocouple materials, that could cause contamination, could decompose, or oxidize

  5. Improving thermocouple service life in slagging gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A.; Thomas, Hugh; Krabbe, Rick

    2005-01-01

    The measurement of temperature within slagging gasifiers for long periods of time is difficult/impossible because of sensor failure or blockage of inputs used to monitor gasifier temperature. One of the most common means of temperature measurement in a gasifier is physically, through the use of thermocouples in a gasifier sidewall. These units can fail during startup, standby, or during the first 40-90 days of gasifier service. Failure can be caused by a number of issues; including thermocouple design, construction, placement in the gasifier, gasifier operation, and molten slag attack of the materials used in a thermocouple assembly. Lack of temperature control in a gasifier can lead to improper preheating, slag buildup on gasifier sidewalls, slag attack of gasifier refractories used to line a gasifier, or changes in desired gas output from a gasifier. A general outline of thermocouple failure issues and attempts by the Albany Research Center to improve the service life of thermocouples will be discussed.

  6. AGR-1 Thermocouple Data Analysis

    SciTech Connect

    Jeff Einerson

    2012-05-01

    This report documents an effort to analyze measured and simulated data obtained in the Advanced Gas Reactor (AGR) fuel irradiation test program conducted in the INL's Advanced Test Reactor (ATR) to support the Next Generation Nuclear Plant (NGNP) R&D program. The work follows up on a previous study (Pham and Einerson, 2010), in which statistical analysis methods were applied for AGR-1 thermocouple data qualification. The present work exercises the idea that, while recognizing uncertainties inherent in physics and thermal simulations of the AGR-1 test, results of the numerical simulations can be used in combination with the statistical analysis methods to further improve qualification of measured data. Additionally, the combined analysis of measured and simulation data can generate insights about simulation model uncertainty that can be useful for model improvement. This report also describes an experimental control procedure to maintain fuel target temperature in the future AGR tests using regression relationships that include simulation results. The report is organized into four chapters. Chapter 1 introduces the AGR Fuel Development and Qualification program, AGR-1 test configuration and test procedure, overview of AGR-1 measured data, and overview of physics and thermal simulation, including modeling assumptions and uncertainties. A brief summary of statistical analysis methods developed in (Pham and Einerson 2010) for AGR-1 measured data qualification within NGNP Data Management and Analysis System (NDMAS) is also included for completeness. Chapters 2-3 describe and discuss cases, in which the combined use of experimental and simulation data is realized. A set of issues associated with measurement and modeling uncertainties resulted from the combined analysis are identified. This includes demonstration that such a combined analysis led to important insights for reducing uncertainty in presentation of AGR-1 measured data (Chapter 2) and interpretation of

  7. Side-welded fast response sheathed thermocouple

    DOEpatents

    Carr, Kenneth R.

    1981-01-01

    A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4-5 times faster and the thermal shock and cycling capabilities are substantially improved.

  8. Side-welded fast response sheathed thermocouple

    DOEpatents

    Carr, K.R.

    A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4 to 5 times faster and the thermal shock and cycling capabilities are substantially improved.

  9. Gold ink coating of thermocouple sheaths

    DOEpatents

    Ruhl, H. Kenneth

    1992-01-01

    A method is provided for applying a gold ink coating to a thermocouple sheath which includes the steps of electropolishing and oxidizing the surface of the thermocouple sheath, then dipping the sheath into liquid gold ink, and finally heat curing the coating. The gold coating applied in this manner is highly reflective and does not degrade when used for an extended period of time in an environment having a temperature over 1000.degree. F. Depending on the application, a portion of the gold coating covering the tip of the thermocouple sheath is removed by abrasion.

  10. Improved thermocouple assemblies for slagging gasifiers

    SciTech Connect

    Chinn, Richard E.; Bennett, James P.; Dahlin, Cheryl L.; Dogan, Cynthia P.; Kwong, Kyei-Sing; Petty, Arthur V.

    2002-09-01

    The thermocouple devices currently employed to monitor temperatures in slagging coal gasifiers typically fail within a few weeks of exposure to the harsh operating environment. As a result, gasifier operators are often left to optimize their system’s performance without precise knowledge of the gasifier operating temperature. Engineers at the Albany Research Center are exploring ways to extend thermocouple life in gasifier environments by enhancing the thermocouple assembly’s resistance to slag penetration and attack. In this presentation, several strategies will be examined that can reduce thermocouple susceptibility to corrosive attack by coal slag, including the use of barrier coatings and improved filler materials. The relative effectiveness of these techniques in laboratory exposure tests will be discussed.

  11. Connecting to Thermocouples with Fewer Lead Wires

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.

    2003-01-01

    A simple technique has been devised to reduce the number of lead wires needed to connect an array of thermocouples to the instruments (e.g., voltmeters) used to read their output voltages. Because thermocouple wires are usually made of expensive metal alloys, reducing the number of lead wires can effect a considerable reduction in the cost of such an array. Reducing the number of wires also reduces the number of terminals and the amount of space needed to accommodate the wires.

  12. Tubular electric heater with a thermocouple assembly

    DOEpatents

    House, R.K.; Williams, D.E.

    1975-08-01

    This patent relates to a thermocouple or other instrumentation which is installed within the walls of a tubular sheath surrounding a process device such as an electric heater. The sheath comprises two concentric tubes, one or both of which have a longitudinal, concave crease facing the other tube. The thermocouple is fixedly positioned within the crease and the outer tube is mechanically reduced to form an interference fit onto the inner tube. (auth)

  13. Adhesive-Bonded Tab Attaches Thermocouples to Titanium

    NASA Technical Reports Server (NTRS)

    Cook, C. F.

    1982-01-01

    Mechanical strength of titanium-alloy structures that support thermocouples is preserved by first spotwelding thermocouples to titanium tabs and then attaching tabs to titanium with a thermosetting adhesive. In contrast to spot welding, a technique previously used for thermocouples, fatigue strength of the titanium is unaffected by adhesive bonding. Technique is also gentler than soldering or attaching thermocouples with a tap screw.

  14. Venogram - leg

    MedlinePlus

    ... the leg. X-rays are a form of electromagnetic radiation like light, but of higher energy, so ... provider if you are pregnant, if you have allergies to any medication, which medications you are taking ( ...

  15. Thin film thermocouples for high temperature measurement

    NASA Astrophysics Data System (ADS)

    Kreider, Kenneth G.

    1989-05-01

    Thin film thermocouples have unique capabilities for measuring surface temperatures at high temperatures (above 800 K) under harsh conditions. Their low mass, approximately 2 x 10(-5) g/mm permits very rapid response and very little disturbance of heat transfer to the surface being measured. This has led to applications inside gas turbine engines and diesel engines measuring the surface temperature of first stage turbine blades and vanes and ceramic liners in diesel cylinders. The most successful high temperature (up to 1300 K) thin film thermocouples are sputter deposited from platinum and platinum-10 percent rhodium targets although results using base metal alloys, gold, and platinel will also be presented. The fabrication techniques used to form the thermocouples, approaches used to solve the high temperature insulation and adherence problems, current applications, and test results using the thin film thermocouples are reviewed. In addition a discussion will be presented on the current problems and future trends related to applications of thin film thermocouples at higher temperatures up to 1900 K.

  16. A coaxial thermocouple for shock tunnel applications.

    PubMed

    Menezes, Viren; Bhat, Sandeep

    2010-10-01

    A chromel-constantan coaxial surface junction thermocouple has been designed, fabricated, calibrated, and tested to measure the temperature-time history on the surface of a body in a hypersonic freestream of Mach 8 in a shock tunnel. The coaxial thermocouple with a diameter of 3.25 mm was flush mounted in the surface of a hemisphere of 25 mm diameter. The hypersonic freestream was of a very low temperature and density, and had a flow time of about a millisecond. Preliminary test results indicate that the thermocouple is quite sensitive to low temperature-rarefied freestreams, and also has a response time of a few microseconds (≈5 μs) to meet the requirements of short duration transient measurements. The sensor developed is accurate, robust, reproducible, and is highly inexpensive. PMID:21034112

  17. [Leg ulcers].

    PubMed

    Wollina, U; Unger, L; Stelzner, C; Machetanz, J; Schellong, S

    2013-11-01

    The lower leg is in particular prone to the development of ulceration. Many different causes may lead to ulceration. Thus, a thorough diagnosis is mandatory, and a biopsy is often required. By far the most common type is the classical venous ulcer due to chronic venous insufficiency, located at the medial ankle. A more complicated-and more difficult to treat-type of venous ulcer is arthrogenic congestion syndrome with its extreme variant of a "legging" ulcer. In cases with severe peripheral arterial disease, an arterial ulcer may develop. The hypertensive ulcer Martorell is associated with arterial hypertension and diabetes; the underlying pathology is occlusion of arteriolar vessels. A typical diabetic ulceration is the necrobiosis lipoidica. Important differential diagnoses of leg ulceration include pyoderma gangrenosum and the calciphylactic ulcer. Due to a long-standing course, an ulceration may turn malignant. Vice versa, ulceration may occur as sign of a primary malignant lesion. PMID:24005788

  18. A thermocouple thermode for small animals

    NASA Technical Reports Server (NTRS)

    Williams, B. A.

    1972-01-01

    Thermode composed of two thin-walled stainless steel hypodermic needles and cooper-constantan thermocouple or small thermistor to indicate temperature at point of perfusion is used to measure brain temperature in animals. Because of relatively small size of thermode, structural damage to brain is minimized.

  19. Accurate temperature measurements with a degrading thermocouple

    SciTech Connect

    Skripnik, Y.A.; Khimicheva, A.I.

    1995-04-01

    Ways are considered of enhancing the accuracy of thermoelectric measurement of temperature. The high accuracy method proposed for monitoring the temperature of an aggressive medium can determine the temperature, irrespective of the instantaneous values of the Seebeck and Peltier coefficients, i.e., irrespective of the uncontrolled thermocouple sensitivity, which varies during use.

  20. Semiconductor cooling by thin-film thermocouples

    NASA Technical Reports Server (NTRS)

    Tick, P. A.; Vilcans, J.

    1970-01-01

    Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

  1. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... Saunders; 2012:chap 11. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  2. Leg Injuries and Disorders

    MedlinePlus

    ... can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures. These injuries can affect the entire leg, or just the foot, ankle, knee, or hip. Certain diseases also lead to leg ...

  3. A program in refractory metal thermocouple research.

    NASA Technical Reports Server (NTRS)

    Burns, G. W.; Hurst, W. S.

    1971-01-01

    Description of a refractory metal thermocouple research program, directed towards establishing the parameters that are necessary to achieve reliable, long term, high temperature thermocouple performance. A description of special apparatus for exposing bare-wire thermoelements to high temperatures in vacuum and in high purity gaseous environments is given, and the design and performance of an ultra-high-vacuum, high-temperature furnace system are described. Bare-wire W-3 per cent Re and W-25 per cent Re thermoelements were exposed at 2400 K in argon, hydrogen, or vacuum, and experienced a shift in their emf-temperature relationship upon initial exposure. After the initial shift, the thermoelements exposed in the gaseous environments experienced no significant further change in their emf-temperature relationship for periods up to 1000 hrs. The thermoelements exposed in vacuum continually drifted in their emf-temperature relationship as a result of the preferential loss of Re by evaporation.

  4. A Miniature Stem Thermocouple Hygrometer 1

    PubMed Central

    Michel, Burlyn E.

    1977-01-01

    An unprotected chromel-constantan thermocouple was mounted in a cavity (4 × 2 × 1 mm) with rounded corners in a chrome-plated brass block (10 × 6 × 4 mm). When installed against a soybean (Glycine max [L.] Merr.) xylem face, sealed with caulking gum, and insulated with polyurethane foam and aluminum foil, even rapidly changing stem water potentials could be followed accurately. Temperature gradients can be a problem. PMID:16660155

  5. Frequency response in short thermocouple wires

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Meeks, E. L.; Ma, J.; Fralick, G. C.

    1992-01-01

    Theoretical expressions are derived for the steady state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for a nonuniform wire with unequal material properties and wire diameters across the junction. The amplitude ratio at low frequency omega approaches 0 agrees with the results of Scadron and Warshawsky (1952) for a steady state temperature distribution. Moreover, the frequency response for a nonuniform wire in the limit of infinite length l approaches infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties. Theoretical expressions are also derived for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire and a two material wire with unequal material properties across the junction. For the case of a one material supported wire, an exact solution is derived which compares favorably with an approximate expression that only matches temperatures at the support junction. Moreover, for the case of a two material supported wire, an analytical expression is derived that closely correlates numerical results. Experimental measurements are made for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 pct. with the theoretical predictions of Forney and Fralick (1991). This is accomplished by choosing a natural frequency omega sub n for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at

  6. Computer program for pulsed thermocouples with corrections for radiation effects

    NASA Technical Reports Server (NTRS)

    Will, H. A.

    1981-01-01

    A pulsed thermocouple was used for measuring gas temperatures above the melting point of common thermocouples. This was done by allowing the thermocouple to heat until it approaches its melting point and then turning on the protective cooling gas. This method required a computer to extrapolate the thermocouple data to the higher gas temperatures. A method that includes the effect of radiation in the extrapolation is described. Computations of gas temperature are provided, along with the estimate of the final thermocouple wire temperature. Results from tests on high temperature combustor research rigs are presented.

  7. A preliminary study of factors affecting the calibration stability of the iridium versus iridium-40 percent rhodium thermocouple

    NASA Technical Reports Server (NTRS)

    Ahmed, Shaffiq; Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.

    1987-01-01

    An iridium versus iridium-40% rhodium thermocouple was studied. Problems associated with the use of this thermocouple for high temperature applications (up to 2000 C) were investigated. The metallurgical studies included X-ray, macroscopic, resistance, and metallographic studies. The thermocouples in the as-received condition from the manufacturer revealed large amounts of internal stress caused by cold working during manufacturing. The thermocouples also contained a large amount of inhomogeneities and segregations. No phase transformations were observed in the alloy up to 1100 C. It was found that annealing the thermocouple at 1800 C for two hours, and then at 1400 C for 2 to 3 hours yielded a fine grain structure, relieving some of the strains, and making the wire more ductile. It was also found that the above annealing procedure stabilized the thermal emf behavior of the thermocouple for application below 1800 C (an improvement from + or - 1% to + or - 0.02% within the range of the test parameters used).

  8. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  9. Leg MRI scan

    MedlinePlus

    ... imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg ... or bone scan Birth defects of the leg, ankle, or foot Bone pain and fever Broken bone ...

  10. Leg Injuries and Disorders

    MedlinePlus

    ... Common leg injuries include sprains and strains, joint dislocations, and fractures. These injuries can affect the entire leg, or just the foot, ankle, knee, or hip. Certain diseases also lead to leg problems. For ...

  11. Performance of Core Exit Thermocouple for PWR Accident Management Action in Vessel Top Break LOCA Simulation Experiment at OECD/NEA ROSA Project

    NASA Astrophysics Data System (ADS)

    Suzuki, Mitsuhiro; Takeda, Takeshi; Nakamura, Hideo

    Presented are experiment results of the Large Scale Test Facility (LSTF) conducted at the Japan Atomic Energy Agency (JAEA) with a focus on core exit thermocouple (CET) performance to detect core overheat during a vessel top break loss-of-coolant accident (LOCA) simulation experiment. The CET temperatures are used to start accident management (AM) action to quickly depressurize steam generator (SG) secondary side in case of core temperature excursion. Test 6-1 is the first test of the OECD/NEA ROSA Project started in 2005, simulating withdraw of a control rod drive mechanism penetration nozzle at the vessel top head. The break size is equivalent to 1.9% cold leg break. The AM action was initiated when CET temperature rose up to 623K. There was no reflux water fallback onto the CETs during the core heat-up period. The core overheat, however, was detected with a time delay of about 230s. In addition, a large temperature discrepancy was observed between the CETs and the hottest core region. This paper clarifies the reasons of time delay and temperature discrepancy between the CETs and heated core during boil-off including three-dimensional steam flows in the core and core exit. The paper discusses applicability of the LSTF CET performance to pressurized water reactor (PWR) conditions and a possibility of alternative indicators for earlier AM action than in Test 6-1 is studied by using symptom-based plant parameters such as a reactor vessel water level detection.

  12. Protective sheath for a continuous measurement thermocouple

    DOEpatents

    Phillippi, R.M.

    1991-12-03

    Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device. 4 figures.

  13. Protective sheath for a continuous measurement thermocouple

    DOEpatents

    Phillippi, R. Michael

    1991-01-01

    Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device.

  14. Leg lengthening.

    PubMed

    Bridgman, S A; Bennet, G C; Evans, G A; Stirling, J

    1993-04-01

    The combined experience of the Royal Hospital for Sick Children, Glasgow and the Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry in lengthening 52 lower limb segments with the Orthofix device is reviewed. Forty-eight segments were lengthened by callotasis, 24 in patients with achondroplasia. Attempted lengthening with chondrodiatasis was performed in 4 patients with leg length discrepancy. With callotasis, planned lengthening was achieved in 43/48 (90%) of segments. There was a small number of significant complications. Angulation or buckling of the new bone was the commonest major complication, and was seen in 10% of segments. Pin tract infection was the predominant minor complication. Premature union was noted commonly in the femurs of achondroplastics, but could usually be overcome with manipulation under anaesthesia. We confirm that callotasis achieves its objectives with fewer complications and operations than the commonly used Wagner method which it should supersede. By contrast, we had major complications in all cases with chondrodiatasis and have abandoned this method. PMID:8478826

  15. Blind-blind prediction by RELAP5/MOD1 for a 0. 1% very small cold-leg break experiment at ROSA-IV large-scale test facility

    SciTech Connect

    Koizumi, Y.; Kumamaru, H.; Kukita, Y.; Kawaji, M.; Osakabe, M.; Schultz, R.R.; Tanaka, M.; Tasaka, K.

    1986-06-01

    The large-scale test facility (LSTF) of the Rig of Safety Assessment No. 4 (ROSA-IV) program is a volumetrically scaled (1/48) pressurized water reactor (PWR) system with an electrically heated core used for integral simulation of small break loss-of-coolant accidents (LOCAs) and operational transients. The 0.1% very small cold-leg break experiment was conducted as the first integral experiment at the LSTF. The test provided a good opportunity to truly assess the state-of-the-art predictability of the safety analysis code RELAP5/MODI CY18 through a blind-blind prediction of the experiment since there was no prior experience in analyzing the experimental data with the code; furthermore, detailed operational characteristics of LSTF were not yet known. The LOCA transient was mitigated by high-pressure charging pump injection to the primary system and bleed and feed operation of the secondary system. The simulated reactor system was safely placed in hot standby condition by engineered safety features similar to those on a PWR. Natural circulation flow was established to effectively remove the decay heat generated in the core. No cladding surface temperature excursion was observed. The RELAP5 code showed good capability to predict thermal-hydraulic phenomena during the very small break LOCA transient. Although all the information needed for the analysis by the RELAP5 code was obtained solely from the engineering drawings for fabrication and the operational specifications, the code predicted key phenomena satisfactorily.

  16. Current drag in two leg quantum ladders

    NASA Astrophysics Data System (ADS)

    Giamarchi, Thierry

    2016-03-01

    A two-leg ladder of either interacting bosons or tightly bound cooper pairs is investigated when a supercurrent is forced in one of the legs of the ladder. The two legs of the ladder are connected by a tunneling term. Using a bosonization representation of such an interacting ladder we show that up to a certain critical current the current in the first wire induces an identical supercurrent in the second wire. When this threshold is exceeded vortices are formed in the system and the current in the second wire reduces even if the driving current increases. Potential applications to condensed matter or cold atomic systems are discussed.

  17. Probe with integrated heater and thermocouple pack

    SciTech Connect

    McCulloch, R.W.; Dial, R.E.; Finnell, W.R.

    1988-02-16

    A gamma thermometer probe for detecting heat produced within the thermometer probe is described comprising: an outer elongate thermometer sheath having a cylindrical cross-section, a length, an outer end and an inner end; an elongate rod having a cylindrical cross-section fitted within the elongate thermometer sheath, the rod being constructed of material that absorbs radiation and produces heat; annular recesses formed between the rod, and sheath and being spaced apart along the length of the rod, the recesses forming annular chambers that are resistive to heat flow; a longitudinal bore extending axially into the rod and being positioned to extend through the cylinders defined by the annular chambers; and an integrated thermocouple pack dimensioned to fit within the longitudinal bore and extending through the cylinders defined by the annular chambers.

  18. Connector for thermocouple leads saves costly wire, makes reliable connectors

    NASA Technical Reports Server (NTRS)

    Miller, H. B.

    1964-01-01

    A connector for use in the thermocouple circuits which is silver-brazed to the metal thermocouple sheath on one end and crimped over the insulation of the flexible lead on the other, assures protection against breakage and abrasion. A moisture-proof insulating material is used to encapsulate the wire junctions.

  19. Thermocouple Extension-Wire-Connections and Low Temperatures

    NASA Technical Reports Server (NTRS)

    Figueroa, Fernando; Mitchell, Mark; Richardson, Gregory

    2000-01-01

    Experiments were carried out to determine the casue of erroneous readings from thermocouples of type K when measuring temperatures of liquid hydrogen. It was believed to be linked to te temperature of the connector used to extend the thermocouple wires to the voltage meter.

  20. Problems encountered in fluctuating flame temperature measurements by thermocouple.

    SciTech Connect

    Donaldson, A. Burl; Lucero, Ralph E.; Gill, Walter; Yilmaz, Nadir

    2008-11-01

    Some thermocouple experiments were carried out in order to obtain sensitivity of thermocouple readings to fluctuations in flames and to determine if the average thermocouple reading was representative of the local volume temperature for fluctuating flames. The thermocouples considered were an exposed junction thermocouple and a fully sheathed thermocouple with comparable time constants. Either the voltage signal or indicated temperature for each test was recorded at sampling rates between 300-4,096 Hz. The trace was then plotted with respect to time or sample number so that time variation in voltage or temperature could be visualized and the average indicated temperature could be determined. For experiments where high sampling rates were used, the signal was analyzed using Fast Fourier Transforms (FFT) to determine the frequencies present in the thermocouple signal. This provided a basic observable as to whether or not the probe was able to follow flame oscillations. To enhance oscillations, for some experiments, the flame was forced. An analysis based on thermocouple time constant, coupled with the transfer function for a sinusoidal input was tested against the experimental results.

  1. Automatic thermocouple positioner for use in vacuum furnaces

    DOEpatents

    Mee, David K.; Stephens, Albert E.

    1981-01-01

    The invention is a simple and reliable mechanical arrangement for automatically positioning a thermocouple-carrying rod in a vacuum-furnace assembly of the kind including a casing, a furnace mounted in the casing, and a charge-containing crucible mounted in the furnace for vertical movement between a lower (loading) position and a raised (charge-melting) position. In a preferred embodiment, a welded-diaphragm metal bellows is mounted above the furnace, the upper end of the bellows being fixed against movement and the lower end of the bellows being affixed to support means for a thermocouple-carrying rod which is vertically oriented and extends freely through the furnace lid toward the mouth of the crucible. The support means and rod are mounted for relative vertical movement. Before pumpdown of the furnace, the differential pressure acting on the bellows causes it to contract and lift the thermocouple rod to a position where it will not be contacted by the crucible charge when the crucible is elevated to its raised position. During pumpdown, the bellows expands downward, lowering the thermocouple rod and its support. The bellows expands downward beyond a point where downward movement of the thermocouple rod is arrested by contact with the crucible charge and to a point where the upper end of the thermocouple extends well above the thermocouple support. During subsequent melting of the charge, the thermocouple sinks into the melt to provide an accurate measurement of melt temperatures.

  2. Automatic thermocouple positioner for use in vacuum furnaces

    DOEpatents

    Mee, D.K.; Stephens, A.E.

    1980-06-06

    The invention is a simple and reliable mechanical arrangement for automatically positioning a thermocouple-carrying rod in a vacuum-furnace assembly of the kind including a casing, a furnace mounted in the casing, and a charge-containing crucible mounted in the furnace for vertical movement between a lower (loading) position and a raised (charge-melting) position. In a preferred embodiment, a welded-diaphragm metal bellows is mounted above the furnace, the upper end of the bellows being fixed against movement and the lower end of the bellows being affixed to support means for a thermocouple-carrying rod which is vertically oriented and extends freely through the furnace lid toward the mouth of the crucible. The support means and rod are mounted for relative vertical movement. Before pumpdown of the furnace, the differential pressure acting on the bellows causes it to contract and lift the thermocouple rod to a position where it will not be contacted by the crucible charge when the crucible is elevated to its raised position. During pumpdown, the bellows expands downward, lowering the thermocouple rod and its support. The bellows expands downward beyond a point where downward movement of the thermocouple rod is arrested by contact with the crucible charge and to a point where the upper end of the thermocouple extends well above the thermocouple support. During subsequent melting of the charge, the thermocouple sinks into the melt to provide an accurate measurement of melt temperatures.

  3. Problems Encountered in Fluctuating Flame Temperature Measurements by Thermocouple

    PubMed Central

    Yilmaz, Nadir; Gill, Walt; Donaldson, A. Burl; Lucero, Ralph E.

    2008-01-01

    Some thermocouple experiments were carried out in order to obtain sensitivity of thermocouple readings to fluctuations in flames and to determine if the average thermocouple reading was representative of the local volume temperature for fluctuating flames. The thermocouples considered were an exposed junction thermocouple and a fully sheathed thermocouple with comparable time constants. Either the voltage signal or indicated temperature for each test was recorded at sampling rates between 300-4,096 Hz. The trace was then plotted with respect to time or sample number so that time variation in voltage or temperature could be visualized and the average indicated temperature could be determined. For experiments where high sampling rates were used, the signal was analyzed using Fast Fourier Transforms (FFT) to determine the frequencies present in the thermocouple signal. This provided a basic observable as to whether or not the probe was able to follow flame oscillations. To enhance oscillations, for some experiments, the flame was forced. An analysis based on thermocouple time constant, coupled with the transfer function for a sinusoidal input was tested against the experimental results.

  4. Miniature sheathed thermocouples for turbine blade temperature measurement

    NASA Technical Reports Server (NTRS)

    Holanda, R.; Glawe, G. E.; Krause, L. N.

    1974-01-01

    An investigation was made of sheathed thermocouples for turbine blade temperature measurements. Tests were performed on the Chromel-Alumel sheathed thermocouples with both two-wire and single-wire configurations. Sheath diameters ranged from 0.25 to 0.76 mm, and temperatures ranged from 1080 to 1250 K. Both steady-state and thermal cycling tests were performed for times up to 450 hr. Special-order and commercial-grade thermocouples were tested. The tests showed that special-order single-wire sheathed thermocouples can be obtained that are reliable and accurate with diameters as small as 0.25 mm. However, all samples of 0.25-mm-diameter sheathed commercial-grade two-wire and single-wire thermocouples that were tested showed unacceptable drift rates for long-duration engine testing programs. The drift rates were about 1 percent in 10 hr. A thermocouple drift test is recommended in addition to the normal acceptance tests in order to select reliable miniature sheathed thermocouples for turbine blade applications.

  5. Correcting thermocouple measurements for radiation loss: A critical review

    SciTech Connect

    Shaddix, C.R.

    1999-07-01

    Thermocouples are one of the simplest and most ubiquitous experimental diagnostics in combustion research and high-temperature process flows. However, quantitative interpretation of thermocouple measurements in high-temperature environments is hampered by the need to account for important heat transfer mechanisms associated with the thermocouple wire and junction, especially thermal radiation. A number of assumptions and simplifications are of necessity incorporated in applying a radiation-correction to a thermocouple measurement, but the assumptions made in different investigations have often been poorly-documented or are inconsistent with the relevant literature guidance. This paper reviews the considerations in performing an energy balance on practical thermocouple junctions and assesses the best available information regarding the appropriate choices to make in performing radiation corrections. In particular, the effects of Nusselt number correlation, thermocouple wire and junction size, the local gas mixture transport properties, and the thermocouple emissivity are explored. The magnitude of the calculated radiation correction for different assumed values of the relevant variables is illustrated.

  6. Metallic and ceramic thin film thermocouples for gas turbine engines.

    PubMed

    Tougas, Ian M; Amani, Matin; Gregory, Otto J

    2013-01-01

    Temperatures of hot section components in today's gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today's engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire) thermocouples. PMID:24217356

  7. Applications of Thin Film Thermocouples for Surface Temperature Measurement

    NASA Technical Reports Server (NTRS)

    Martin, Lisa C.; Holanda, Raymond

    1994-01-01

    Thin film thermocouples provide a minimally intrusive means of measuring surface temperature in hostile, high temperature environments. Unlike wire thermocouples, thin films do not necessitate any machining of the surface, therefore leaving intact its structural integrity. Thin films are many orders of magnitude thinner than wire, resulting in less disruption to the gas flow and thermal patterns that exist in the operating environment. Thin film thermocouples have been developed for surface temperature measurement on a variety of engine materials. The sensors are fabricated in the NASA Lewis Research Center's Thin Film Sensor Lab, which is a class 1000 clean room. The thermocouples are platinum-13 percent rhodium versus platinum and are fabricated by the sputtering process. Thin film-to-leadwire connections are made using the parallel-gap welding process. Thermocouples have been developed for use on superalloys, ceramics and ceramic composites, and intermetallics. Some applications of thin film thermocouples are: temperature measurement of space shuttle main engine turbine blade materials, temperature measurement in gas turbine engine testing of advanced materials, and temperature and heat flux measurements in a diesel engine. Fabrication of thin film thermocouples is described. Sensor durability, drift rate, and maximum temperature capabilities are addressed.

  8. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    PubMed Central

    Tougas, Ian M.; Amani, Matin; Gregory, Otto J.

    2013-01-01

    Temperatures of hot section components in today's gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today's engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire) thermocouples. PMID:24217356

  9. Thermocouple Calibration and Accuracy in a Materials Testing Laboratory

    NASA Technical Reports Server (NTRS)

    Lerch, B. A.; Nathal, M. V.; Keller, D. J.

    2002-01-01

    A consolidation of information has been provided that can be used to define procedures for enhancing and maintaining accuracy in temperature measurements in materials testing laboratories. These studies were restricted to type R and K thermocouples (TCs) tested in air. Thermocouple accuracies, as influenced by calibration methods, thermocouple stability, and manufacturer's tolerances were all quantified in terms of statistical confidence intervals. By calibrating specific TCs the benefits in accuracy can be as great as 6 C or 5X better compared to relying on manufacturer's tolerances. The results emphasize strict reliance on the defined testing protocol and on the need to establish recalibration frequencies in order to maintain these levels of accuracy.

  10. Development of Thin Film Ceramic Thermocouples for High Temperature Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2004-01-01

    The maximum use temperature of noble metal thin film thermocouples of 1100 C (2000 F) may not be adequate for use on components in the increasingly harsh conditions of advanced aircraft and next generation launch technology. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically found in the form of rods or probes. NASA Glenn Research Center is investigating the feasibility of ceramics as thin film thermocouples for extremely high temperature applications to take advantage of the stability and robustness of ceramics and the non-intrusiveness of thin films. This paper will discuss the current state of development in this effort.

  11. Restless legs syndrome

    MedlinePlus

    Restless legs syndrome (RLS) is a nervous system problem that causes you to feel an unstoppable urge to get ... DA, Bista SR, et al. The treatment of restless legs syndrome and periodic limb movement disorder in adults-an ...

  12. Leg MRI scan

    MedlinePlus

    ... resonance imaging) scan of the leg uses strong magnets to create pictures of the leg. This may ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  13. High Temperature Irradiation Resistant Thermocouple (HTIR-TC)

    SciTech Connect

    2011-01-01

    INL researchers have created a new thermocouple that can resist high temperature and radiation. This device will improve safety and reduce costs associated with unit failures. Learn more about INL research at http://www.facebook.com/idahonationallaboratory

  14. Type C Thermocouple Performance at 1500 ºC

    SciTech Connect

    Joy L. Rempe; Darrell L. Knudson; Joshua E. Daw; S. Curtis Wilkins

    2008-11-01

    Experience with Type C thermocouples operating for long periods in the 1400 to 1600 °C temperature range indicate that significant decalibration occurs, often leading to expensive downtime and material waste. As part of an effort to understand the mechanisms causing drift in these thermocouples, the Idaho National Laboratory conducted a long duration test at 1500 °C containing eight Type C thermocouples. As reported in this paper, results from this long duration test were adversely affected due to oxygen ingress. Nevertheless, results provide important insights about the impact of precipitate formation on thermoelectric response. Post-test examinations indicate that the thermocouple signal was not adversely impacted by the precipitates detected after 1000 hours of heating at 1500 °C and suggest that the signal would not have been adversely impacted by these precipitates for longer durations (if oxygen ingress had not occurred in this test).

  15. High Temperature Irradiation Resistant Thermocouple (HTIR-TC)

    ScienceCinema

    None

    2013-05-28

    INL researchers have created a new thermocouple that can resist high temperature and radiation. This device will improve safety and reduce costs associated with unit failures. Learn more about INL research at http://www.facebook.com/idahonationallaboratory

  16. Type C thermocouple performance at 1500 °C

    NASA Astrophysics Data System (ADS)

    Rempe, J. L.; Knudson, D. L.; Daw, J. E.; Wilkins, S. C.

    2008-11-01

    Experience with Type C thermocouples operating for extended times in the 1400-1600 °C temperature range indicates that significant decalibration occurs, often leading to expensive downtime and material waste. As part of an effort to understand the mechanisms causing drift in these thermocouples, the Idaho National Laboratory conducted a long duration (3000 h) test at 1500 °C containing eight Type C thermocouples. As reported in this paper, results from this long duration test were adversely affected due to oxygen ingress. Nevertheless, results provide important insights about the impact of precipitate formation due to material phase changes on thermoelectric response. Post-test examinations indicate that the thermocouple signal was not adversely impacted by the formation of precipitates detected after 1000 h of heating at 1500 °C and suggest that the signal would not be adversely impacted by these precipitates for longer durations.

  17. SP-100 W/Re thermocouple calibration techniques

    SciTech Connect

    Cannon, N.S.; Knight, R.C.

    1992-01-01

    The accuracy requirement of the SP-100 Temperature Sensor Program for the reference tungsten/rhenium metal-sheathed thermocouple sensor is {plus minus}1.4% of the reading (in Kelvin) at space reactor operating temperature (nominally 1375 K) over the operating life of the reactor. This is a stringent requirement considering that the as-fabricated base wire limits of error'' are generally specified at roughly {plus minus}1.0% for exposure temperatures above 700 K. Although the thermocouples will be located out of the reactor's neutron field so that irradiation decalibration is expected to be negligible, thermal exposure effects will probably cause the thermocouple to drift out of specification during the 10-yr reactor operating life. A plan to accurately quantify thermocouple drift with aging time, and thus provide on-board calibration for the sensor is described.

  18. Foot, leg, and ankle swelling

    MedlinePlus

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Foot, leg, and ankle swelling is common when the person also: Is overweight Has a blood clot in the leg Is older Has ...

  19. Thin-Film Ceramic Thermocouples Fabricated and Tested

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Gregory, Otto J.; Blaha, Charles A.

    2004-01-01

    The Sensors and Electronics Technology Branch of the NASA Glenn Research Center is developing thin-film-based sensors for surface measurement in propulsion system research. Thin-film sensors do not require special machining of the components on which they are mounted, and they are considerably thinner than wire- or foil-based sensors. One type of sensor being advanced is the thin-film thermocouple, specifically for applications in high-temperature combustion environments. Ceramics are being demonstrated as having the potential to meet the demands of thin-film thermocouples in advanced aerospace environments. The maximum-use temperature of noble metal thin-film thermocouples, 1500 C (2700 F), may not be adequate for components used in the increasingly harsh conditions of advanced aircraft and next-generation launch vehicles. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically in the form of bulky rods or probes. As part of ASTP, Glenn's Sensors and Electronics Technology Branch is leading an in-house effort to apply ceramics as thin-film thermocouples for extremely high-temperature applications as part of ASTP. Since the purity of the ceramics is crucial for the stability of the thermocouples, Glenn's Ceramics Branch and Case Western Reserve University are developing high-purity ceramic sputtering targets for fabricating high-temperature sensors. Glenn's Microsystems Fabrication Laboratory, supported by the Akima Corporation, is using these targets to fabricate thermocouple samples for testing. The first of the materials used were chromium silicide (CrSi) and tantalum carbide (TaC). These refractory materials are expected to survive temperatures in excess of 1500 C. Preliminary results indicate that the thermoelectric voltage output of a thin-film CrSi versus TaC thermocouple is 15 times that of the standard type R (platinum-rhodium versus platinum) thermocouple, producing 20 mV with a 200

  20. Rocket plume temperature measurement by wire welded thermocouples

    NASA Astrophysics Data System (ADS)

    Xu, Qiang

    2006-05-01

    The plume of solid rocket motor is a high velocity flow with high temperature. Temperature distribution in the plume is of great interest for analyzing the compatibility of rocket weapon system. The high temperature exhausted flow field would cause damage on certain equipment and loading vehicles. An instantaneous temperature field with sharp step is established by the exhausted flow field of rocket motor. The increasing rate of the step depends on the flow velocity at cross section of nozzle exit. To perform an accurate measurement of temperature inside the flow field, a thermocouple must be sturdy enough to endure the flow impingement. In the meantime, the thermocouple must have a short time constant to trace the temperature fluctuation in flow field and a small size to avoid disturbing the flow field severely. The dynamic performance of the thermocouples used in exhausted flow temperature measurement must be evaluated before the experiment. The thermocouple which can be used in measuring the temperature distribution in rocket plume was presented in this paper. A NAMNAC (R) self-renew-erode thermocouples with a nominal time constant of 10 microseconds was used as a reference in a dynamic calibration test for this kind of thermocouple. The thermocouple could trace the temperature increase in the exhausted flow perfectly. This kind of thermocouples was used in several real tests of rocket motors, such as the temperature in free exhausted flow field of a stationary rocket motor test, the stagnate temperature in a shock flow field during the launching of a rocket, and the temperature in a launch tube.

  1. Design and Analysis of Novel Micromachined Thermocouples with Vertical Free-Standing High-Aspect-Ratio Geometry

    NASA Astrophysics Data System (ADS)

    Wick, M.; Hedler, H.; Seidel, H.

    2015-06-01

    This paper describes the design and analysis of free-standing three-dimensional (3D) thermocouples (TCs) for uncooled high-resolution infrared imaging. In contrast to the conventional horizontal thermocouple design, our 3D TCs consist of vertically oriented coaxial thermoelectric legs covered by an infrared absorber plate. The high aspect ratio of the 3D TCs of up to 100:1 leads to increased thermal resistance and, thus, higher electrical responsivity. Furthermore, reduced lateral dimensions of the device are achieved by coaxial mounting. This allows a closely packed arrangement of 3D TCs, which results in a high-resolution microarray sensor setup. These features represent the 3D TC's innovative uniqueness and open up new possibilities for further minimized uncooled thermal sensors and low-cost high-resolution imagers. We developed a fabrication process for 3D TCs with doped polysilicon as thermoelectric legs and a geometry with diameter of m and length of m. Performance analysis has been carried out using the lumped-heat-capacity method, resulting in an electrical responsivity and specific detectivity of a 3D TC of 383 V/W and cm /W, respectively.

  2. An updated T-series thermocouple measurement system for high-accuracy temperature measurements of the MMT primary mirror

    NASA Astrophysics Data System (ADS)

    Clark, D.; Gibson, J. D.

    2012-09-01

    Starting in 2009, MMTO began design and installation of a new set of electronics to measure a set of radiallydistributed type T thermocouples installed after the primary mirror polishing was completed. These thermocouples are arranged in both single measurement points and as thermopiles for differential temperature sensing. Since the goal of the primary mirror temperature control system is to minimize mirror seeing and mirror figure errors induced by temperature variation across the primary mirror, it depends on excellent accuracy from the temperature sensing system. The new electronics encompass on-board cold-junction compensation, real-time ITS-90 curve fitting, and Ethernet connectivity to the data servers running in the MMTO software infrastructure. We describe the hardware design, system wiring, and software used in this system.

  3. Traceable Co-C eutectic points for thermocouple calibration

    SciTech Connect

    Jahan, F.; Ballico, M. J.

    2013-09-11

    National Measurement Institute of Australia (NMIA) has developed a miniature crucible design suitable for measurement by both thermocouples and radiation thermometry, and has established an ensemble of five Co-C eutectic-point cells based on this design. The cells in this ensemble have been individually calibrated using both ITS-90 radiation thermometry and thermocouples calibrated on the ITS-90 by the NMIA mini-coil methodology. The assigned ITS-90 temperatures obtained using these different techniques are both repeatable and consistent, despite the use of different furnaces and measurement conditions. The results demonstrate that, if individually calibrated, such cells can be practically used as part of a national traceability scheme for thermocouple calibration, providing a useful intermediate calibration point between Cu and Pd.

  4. High Temperature Thermocouples For In-pile Applications

    SciTech Connect

    J. L. Rempe; S. C. Wilkins

    2005-10-01

    Traditional methods for measuring temperature in-pile degrade at temperatures above 1080 degrees C. Hence, a project has been initiated to explore the use of specialized thermocouples that are composed of materials that are able to withstand higher temperature, in-pile test conditions. Results from efforts to develop, fabricate and evaluate the performance of these specialized thermocouples are reported in this paper. Candidate materials were evaluated for their ability to withstand irradiation, to resit material interactions and to remain ductile at high temperatures. In addition, candidate thermocouples were evaluated based on their resolution over the temperature ranges of interest. Results from these evaluations are reported, and additional on-going development activities are summarized.

  5. Frequency response of a thermocouple wire: Effects of axial conduction

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Fralick, G. C.

    1990-01-01

    Theoretical expressions are derived for the steady-state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a uniform thermocouple wire and a nonuniform wire with unequal material properties and wire diameters across the junction. For the case of a uniform wire, the amplitude ratio and phase angle compare favorably with the series solution of Scadron and Warshawsky (1952) except near the ends of the wire. For the case of a non-uniform wire, the amplitude ratio at low frequency omega yields 0 agrees with the results of Scadron and Warshawsky for a steady-state temperature distribution. Moreover, the frequency response for a non-uniform wire in the limit of infinite length l yields infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties.

  6. An Innovative Flow-Measuring Device: Thermocouple Boundary Layer Rake

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Wrbanek, John D.; Blaha, Charles A.

    2001-01-01

    An innovative flow-measuring device, a thermocouple boundary layer rake, was developed. The sensor detects the flow by using a thin-film thermocouple (TC) array to measure the temperature difference across a heater strip. The heater and TC arrays are microfabricated on a constant-thickness quartz strut with low heat conductivity. The device can measure the velocity profile well into the boundary layer, about 65 gm from the surface, which is almost four times closer to the surface than has been possible with the previously used total pressure tube.

  7. Thermocouples For High Temperature In-Pile Testing

    SciTech Connect

    J. L. Rempe

    2005-11-01

    Many advanced nuclear reactor designs require new fuel, cladding and structural materials. Data are needed to characeterize the performance of these new materials in high temperature, oxidizing and radiation conditions. To obtain this data, robust instrumentation is needed htat can survive proposed test conditions. Traditional methods for measuring temperature in-pile degrade at temperatures above 1080 degrees C. Hence, a project was intiated to develop specialized thermocouples for high temperature in-pile applications (see Rempe and Wilkins, 2005). This paper summarizes efforts to develop, fabricate and evaluate these specialized thermocouples.

  8. Failure of sheathed thermocouples due to thermal cycling

    SciTech Connect

    Anderson, R.L.; Ludwig, R.L.

    1982-03-01

    Open circuit failures (up to 100%) in small-diameter thermocouples used in electrically heated nuclear fuel rod simulator prototypes during thermal cycling tests were investigated to determine the cause(s) of the failures. The experiments conducted to determine the relative effects of differential thermal expansion, wire size, grain size, and manufacturing technology are described. It was concluded that the large grain size and embrittlement which result from certain common manufacturing annealing and drawing procedures were a major contributing factor in the breakage of the thermocouple wires.

  9. In Situ Observation and Investigation of Mold Flux Crystallization by Using Double Hot Thermocouple Technology

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin; Huang, Daoyuan; Wei, Juan; Li, Jin

    2012-08-01

    The crystallization processes of mold fluxes for casting low-carbon (LC) and medium-carbon (MC) steels were investigated by using double hot thermocouple technology (DHTT) in this article. The results showed that the glass phase was first formed at the cold side thermocouple (CH-2), when the LC mold flux (mold flux for casting low-carbon steel) was exposed to the temperature gradient of 1773 K (1500 °C) to 1073 K (800 °C); then, the fine crystals were precipitated at the liquid/glass interface and grew toward glass and later on to liquid phase. However, the crystals were directly formed at CH-2 when MC flux (mold flux for casting medium-carbon steel) was under the same thermal gradient. The growth rate of MC flux crystals was much faster than that of LC ones. Scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS) analyses suggested that the crystals formed in LC mold flux were mainly dendritic cuspidine Ca4Si2O7F2, and the crystals formed from the liquid phase were larger than those from the glass. For MC mold flux, the earlier precipitated crystals were large dendritic Ca4Si2O7F2, whereas the later ones were composed of equiaxed Ca2Al2SiO7 crystals. The results of DHTT measurements were consistent with the time-temperature-transformation (TTT) diagrams and X-ray diffraction (XRD) analysis.

  10. A Comparison of Contemporary Gold Versus Platinum Thermocouples with NIST SRM 1749-Based Thermocouples and Reference Function

    NASA Astrophysics Data System (ADS)

    Coleman, M. J.; Wiandt, T. J.; Harper, T.

    2015-12-01

    Fluke Calibration (formerly Hart Scientific) in American Fork, Utah, USA is a manufacturer of temperature calibration instruments. The company manufactured reference standard gold versus platinum (Au-Pt) thermocouples from 1992 to about 2002. Manufacturing was halted in 2002 because a trend of poor curve-fit results was observed in new batches of wire. After reviewing the possible sources of the problem, it was decided to sample wire from multiple manufacturers and investigate ways to make the curve-fit work better. This paper presents the results from the study of the wire and a characterization technique to help improve characterization of thermocouples made with lower purity wire. Calibration results from NIST SRM material and older Fluke thermocouples are included as well to provide a means of comparison of contemporary wire to NIST SRM era wire.

  11. Thermocouples of molybdenum and iridium alloys for more stable vacuum-high temperature performance

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1978-01-01

    Thermocouples providing stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor are described. Each metal of the sensor is selected from a group of metals comprising molybdenum and iridium and alloys containing only those two metals. The molybdenum, iridium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibility and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys result in improved emf, temperature properties and thermocouple hot junction performance.

  12. Long Duration Performance of High Temperature Irradiation Resistant Thermocouples

    SciTech Connect

    Rempe, Joy L; Knudson, D. L.; Condie, K. G.; Wilkins, S. C.

    2007-05-01

    Many advanced nuclear reactor designs require new fuel, cladding, and structural materials. Data are needed to characterize the performance of these new materials in high temperature, radiation conditions. However, traditional methods for measuring temperature inpile degrade at temperatures above 1100 ºC. To address this instrumentation need, the Idaho National Laboratory (INL) developed and evaluated the performance of a high temperature irradiation-resistant thermocouple that contains alloys of molybdenum and niobium. To verify the performance of INL’s recommended thermocouple design, a series of high temperature (from 1200 to 1800 ºC) long duration (up to six months) tests has been initiated. This paper summarizes results from the tests that have been completed. Data are presented from 4000 hour tests conducted at 1200 and 1400 ºC that demonstrate the stability of this thermocouple (less than 2% drift). In addition, post test metallographic examinations are discussed which confirm the compatibility of thermocouple materials throughout these long duration, high temperature tests.

  13. Thermocouples--The Most Widely Used Temperature Sensor in Manufacturing

    ERIC Educational Resources Information Center

    Mitts, Charles R.

    2006-01-01

    Researchers predict that future developments in nanotechnology will bring incredible, almost inconceivable, change to the manufacturing industry. For now, though, one of technology's most trusted tools remains very relevant: In the field of thermometry, thermocouples are a tried and true technology. As a consequence, material on thermocouples…

  14. Studies of noble-metal thermocouple stability at high temperatures

    NASA Technical Reports Server (NTRS)

    Freeze, P.; Thomas, D. B.

    1976-01-01

    Two investigatory studies on performance characteristics of noble-metal thermocouples are described. (1) thermoelectric stability as affected by preferential oxidation of iridium in the system iridium-40% rhodium versus iridium, and (2) the effects of temperature gradients on the emf stability of the systems platinum-13% rhodium versus platinum and iridium-40% rhodium versus iridium, operating in air. The stability investigation was carried out at three temperatures - 1700, 1850, and 2000 C - by comparing the output of the test thermocouple in air with the output of an identically constructed reference thermocouple in nitrogen. The results show that no calibration shift was observed producing a change in output greater than that corresponding to a 2.0% change in the indicated temperature for all samples tested. The investigation of gradient effects was carried out by subjecting test thermocouples to both severe and mild gradients for periods up to 200 hours. For the platinum system, the operating temperature was 1500 C with gradients of 1475 and 700 C/cm; for the iridium system, 2000 C with gradients of 700, 1500, and 1975 C/cm. Exposure to temperature gradients was found to introduce significant changes in calibration for both systems. In both investigations, the thermoelements were examined by means of electron-probe analysis and by metallographic methods to detect chemical and structural changes. Data and micrographs are presented.

  15. High temperature thermocouple development program, part A and part B

    NASA Technical Reports Server (NTRS)

    Toenshoff, D. A.; Zysk, E. D.; Fleischner, P. L.

    1972-01-01

    The problem of extending the useful life of thermocouples intended for in-core and out-of-core thermionic applications in a vacuum environment at temperatures up to 2273 K for periods of time up to 10,000 hours was investigated. Many factors that may influence this useful life were examined, and a basic probe design was developed. With a few modifications, twenty-three thermocouple assemblies were fabricated. Generally the finished thermocouple consisted of solid doped W-3% Re and W-25% Re wires and high purity and high density BeO insulators, and was sheathed in a high purity tantalum tube. In a few probes, stranded thermocouple wires were substituted; commercial grade BeO was used; and in two cases, CVD W-22% Re tubing was used. Each of the components was made of the highest purity materials available; was subjected to special cleaning steps, and was assembled in a class 10,000 clean room. Pertinent physical and chemical properties were determined on each of the components. Special processing techniques were used in the fabrication of the high purity (99.95%), high density (over 95% of theoretical) BeO.

  16. Low-Cost Thermocouple Signal-Conditioning Module

    ERIC Educational Resources Information Center

    Lenzi, Marcelo K.; Silva, Fabricio M.; Lima, Enrique L.; Pinto, Jose Carlos; Cunningham, Michael F.

    2005-01-01

    It is well known that reaction rates and physical properties of any substance depend on the temperature. Therefore, an accurate temperature measurement is a key factor for successful activities both in chemical laboratories and industrial plants. Although plenty of sensors can be adopted for temperature measurements, thermocouples are the most…

  17. A Multiple-range Self-balancing Thermocouple Potentiometer

    NASA Technical Reports Server (NTRS)

    Warshawsky, I; Estrin, M

    1951-01-01

    A multiple-range potentiometer circuit is described that provides automatic measurement of temperatures or temperature differences with any one of several thermocouple-material pairs. Techniques of automatic reference junction compensation, span adjustment, and zero suppression are described that permit rapid selection of range and wire material, without the necessity for restandardization, by setting of two external tap switches.

  18. Restless legs syndrome

    MedlinePlus

    ... they sleep. This condition is called periodic limb movement disorder. All of these symptoms make it hard to ... treatment of restless legs syndrome and periodic limb movement disorder in adults-an update for 2012: practice parameters ...

  19. Leg lengthening and shortening

    MedlinePlus

    ... to very unequal leg lengths. They include: Poliomyelitis Cerebral palsy Small, weak muscles or short, tight (spastic) muscles, ... Mosby; 2012:chap 29. Read More Broken bone Cerebral palsy Legg-Calve-Perthes disease Long bones Polio Update ...

  20. Restless Legs Syndrome

    MedlinePlus

    ... Funding Information Research Programs Training & Career Awards Enhancing Diversity Find People About NINDS NINDS Restless Legs Syndrome ... News From NINDS | Find People | Training | Research | Enhancing Diversity Careers@NINDS | FOIA | Accessibility Policy | Contact Us | Privacy ...

  1. Reprint of : Current drag in two leg quantum ladders

    NASA Astrophysics Data System (ADS)

    Giamarchi, Thierry

    2016-08-01

    A two-leg ladder of either interacting bosons or tightly bound cooper pairs is investigated when a supercurrent is forced in one of the legs of the ladder. The two legs of the ladder are connected by a tunneling term. Using a bosonization representation of such an interacting ladder we show that up to a certain critical current the current in the first wire induces an identical supercurrent in the second wire. When this threshold is exceeded vortices are formed in the system and the current in the second wire reduces even if the driving current increases. Potential applications to condensed matter or cold atomic systems are discussed.

  2. Human responses to cold.

    PubMed

    Rintamäki, Hannu

    2007-01-01

    The thermoneutral ambient temperature for naked and resting humans is ca. 27 degrees C. Exposure to cold stimulates cold receptors of the skin which causes cold thermal sensations and stimulation of the sympathetic nervous system. Sympathetic stimulation causes vasoconstriction in skin, arms and legs. Diminished skin and extremity blood flow increases the thermal insulation of superficial tissues more than 300% corresponding to 0.9 clo (0.13 degrees C x m(-2) x W(-1)). With thermoregulatory vasoconstriction/ vasodilatation the body heat balance can be maintained within a range of ca. 4 degrees C, the middle of the range being at ca. 21 degrees C when light clothing is used. Below the thermoneutral zone metabolic heat production (shivering) is stimulated and above the zone starts heat loss by evaporation (sweating). Cold induced vasoconstriction increases blood pressure and viscosity and decreases plasma volume consequently increasing cardiac work. Cold induced hypertensive response can be counteracted by light exercise, while starting heavy work in cold markedly increases blood pressure. Under very cold conditions the sympathetic stimulation opens the anastomoses between arterioles and venules which increases skin temperatures markedly but temporarily, especially in finger tips. Adaptation to cold takes ca. 2 weeks, whereafter the physiological responses to cold are attenuated and cold exposure is subjectively considered less stressful. PMID:17929604

  3. Actuator device for artificial leg

    NASA Technical Reports Server (NTRS)

    Burch, J. L. (Inventor)

    1976-01-01

    An actuator device is described for moving an artificial leg of a person having a prosthesis replacing an entire leg and hip joint. The device includes a first articulated hip joint assembly carried by the natural leg and a second articulated hip joint assembly carried by the prosthesis whereby energy from the movement of the natural leg is transferred by a compressible fluid from the first hip joint assembly to the second hip joint assembly for moving the artificial leg.

  4. Thin film thermocouples for thermoelectric characterization of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Grayson, Matthew; Zhou, Chuanle; Varrenti, Andrew; Chyung, Seung Hye; Long, Jieyi; Memik, Seda

    2011-03-01

    The increased use of nanostructured materials as thermoelectrics requires reliable and accurate characterization of the anisotropic thermal coefficients of small structures, such as superlattices and quantum wire networks. Thin evaporated metal films can be used to create thermocouples with a very small thermal mass and low thermal conductivity, in order to measure thermal gradients on nanostructures and thereby measure the thermal conductivity and the Seebeck coefficient of the nanostructure. In this work we confirm the known result that thin metal films have lower Seebeck coefficients than bulk metals, and we also calibrate the Seebeck coefficient of a thin-film Ni/Cr thermocouple with 50 nm thickness, showing it to have about 1/4 the bulk value. We demonstrate reproducibility of this thin-filmSeebeck coefficient on multiple substrates, and we show that this coefficient does, in fact, change as a function of film thickness. We will discuss prototype measurement designs and preliminary work as to how these thin films can be used to study both Seebeck coefficients and thermal conductivities of superlattices in various geometries. The same technology can in principle be used on integrated circuits for thermal mapping, under the name ``Integrated On-Chip Thermocouple Array'' (IOTA).

  5. Venous leg ulcers

    PubMed Central

    2011-01-01

    Introduction Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 101 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids

  6. Enhancements to High Temperature In-Pile Thermocouple Performance

    SciTech Connect

    J. C. Crepeau; J. L. Rempe; J. E. Daw; D. L. Knudson; K. G. Condie; S. C. Wilkins

    2008-03-01

    A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped lybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of the art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 °C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing them to

  7. Enhancements to High Temperature In-Pile Thermocouple Performance

    SciTech Connect

    J.C. Crepeau; J.L. Rempe; J.E. Daw; D.L. Knudson: K.G. Condie; S.C. Wilkins

    2008-03-31

    A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped molybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of the art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing them to

  8. Hysteresis Effects and Strain-Induced Homogeneity Effects in Base Metal Thermocouples

    NASA Astrophysics Data System (ADS)

    Pavlasek, P.; Elliott, C. J.; Pearce, J. V.; Duris, S.; Palencar, R.; Koval, M.; Machin, G.

    2015-03-01

    Thermocouples are used in a wide variety of industrial applications in which they play an important role for temperature control and monitoring. Wire inhomogeneity and hysteresis effects are major sources of uncertainty in thermocouple measurements. To efficiently mitigate these effects, it is first necessary to explore the impact of strain-induced inhomogeneities and hysteresis, and their contribution to the uncertainty. This article investigates homogeneity and hysteresis effects in Types N and K mineral-insulated metal-sheathed (MIMS) thermocouples. Homogeneity of thermocouple wires is known to change when mechanical strain is experienced by the thermoelements. To test this influence, bends of increasingly small radii, typical in industrial applications, were made to a number of thermocouples with different sheath diameters. The change in homogeneity was determined through controlled immersion of the thermocouple into an isothermal liquid oil bath at and was found to be very small at for Type K thermocouples, with no measureable change in Type N thermocouples found. An experiment to determine the hysteresis effect in thermocouples was performed on swaged, MIMS Type N and Type K thermocouples, in the temperature range from to . The hysteresis measurements presented simulate the conditions that thermocouples may be exposed to in industrial applications through continuous cycling over 136 h. During this exposure, a characteristic drift from the reference function has been observed but no considerable difference between the heating and cooling measurements was measureable. The measured differences were within the measurement uncertainties; therefore, no hysteresis was observed.

  9. A joint computational and experimental study to evaluate Inconel-sheathed thermocouple performance in flames.

    SciTech Connect

    Brundage, Aaron L.; Nicolette, Vernon F.; Donaldson, A. Burl; Kearney, Sean Patrick; Gill, Walter

    2005-09-01

    A joint experimental and computational study was performed to evaluate the capability of the Sandia Fire Code VULCAN to predict thermocouple response temperature. Thermocouple temperatures recorded by an Inconel-sheathed thermocouple inserted into a near-adiabatic flat flame were predicted by companion VULCAN simulations. The predicted thermocouple temperatures were within 6% of the measured values, with the error primarily attributable to uncertainty in Inconel 600 emissivity and axial conduction losses along the length of the thermocouple assembly. Hence, it is recommended that future thermocouple models (for Inconel-sheathed designs) include a correction for axial conduction. Given the remarkable agreement between experiment and simulation, it is recommended that the analysis be repeated for thermocouples in flames with pollutants such as soot.

  10. A modified hot thermocouple apparatus for the study of molten oxide solidification and crystallization

    NASA Astrophysics Data System (ADS)

    Esfahani, Shaghayegh; Danaei, Karim; Budurea, Daniel; Barati, Mansoor

    2016-03-01

    The hot thermocouple technique (HTT) is an experimental method primarily used for studying high temperature phase transformations and interactions. The thermocouple driver is the main component of the apparatus, allowing heating and temperature measurement of the thermocouple that acts as a heating element and temperature sensor simultaneously. Previous setups have employed an ac (alternating current) power feed to the thermocouple, creating inherent limitations to the time interval and frequency of temperature sensing and control. In this article, the development of a dc (direct current)-based thermocouple driver is discussed. The new setup allows higher frequency (480 Hz) of heating pulses applied to the thermocouple. The higher switching frequency improves the thermocouple temperature reading accuracy and decreases the time interval between the measurements by a factor of eight, compared to existing HTT devices. The development of a dc power HTT apparatus, its calibration, and examples of its use in the studies of the crystallization of oxide mixtures are presented in this article.

  11. Thermocouples of tantalum and rhenium alloys for more stable vacuum-high temperature performance

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1977-01-01

    Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising tantalum and rhenium and alloys containing only those two metals. The tantalum, rhenium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the tantalum, rhenium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.

  12. [Sonographic leg length measurement].

    PubMed

    Holst, A; Thomas, W

    1989-03-01

    After brief presentation of the clinical and radiological methods to measure the leg length and the leg length difference the authors outline the new diagnostic method for measuring the leg length and the leg length difference by means of real time sonography. Postmortem tests and clinical examples show that ultrasound is ideal to determine exactly the length of femur and tibia. The joint gaps on the hip, knee and upper ankle joint can be demonstrated by means of a 5 MHz linear scanner. A 1 mm strong metal bar on the skin and under the scanner is placed at right angles to the longitudinal axis of the body so that the bar can be seen in the centre. A measuring device gives the distances of the joint gaps in cm so that the difference correspond to the real length of femur and tibia. This standardised measuring is done by a particularly developed bearing and measuring device. The results of the sonographical measurements on 20 corpses and checking after consecutive dissections showed in 75% of cases a 100% sonographic measuring accuracy of the total leg length. The separately considered results for femur (85%) and tibia (90) were even better. The maximum sonographic measuring fault was 1.0 cm for the femur (in one case) and 0.5 cm for the tibia, respectively. All sonographic measurements were performed with the Sonoline SL-1 of the Siemens Company (Erlangen, W-Germany). Thus, sonographical measuring of the leg length offers a reliable, non-invasive method that can be repeated as often as necessary and is simply executed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2652268

  13. 20. DETAIL, TYPICAL LEG CONNECTION, CROSS BRACING AT LEG, WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL, TYPICAL LEG CONNECTION, CROSS BRACING AT LEG, WITH CROSSED BRACE BLOCK, GROUND WIRES AND GUIDE WIRE. - Hat Point Fire Lookout Tower, Forest Service Road #4340, 24 miles from Imnaha, Imnaha, Wallowa County, OR

  14. [List of diagnostic tests and procedures in leg ulcer].

    PubMed

    Spoljar, Sanja

    2013-10-01

    Many factors contribute to the pathogenesis of leg ulcer. Most patients have venous leg ulcer due to chronic venous insufficiency. Less often, patients have arterial leg ulcer resulting from peripheral arterial occlusive disease, the most common cause of which is arteriosclerosis. Leg ulcer may be of a mixed arteriovenous origin. In diabetic patients, distal symmetric neuropathy and peripheral vascular disease are probably the most important etiologic factors in the development of diabetic leg ulcer. Other causes of chronic leg ulcers are hematologic diseases, autoimmune diseases, genetic defects, infectious diseases, primary skin diseases, cutaneous malignant diseases, use of some medications and therapeutic procedures, and numerous exogenous factors. Diagnosis of leg ulcer is based on medical history, inspection, palpation of skin temperature, palpation of arteries, fascia holes, presence and degree of edema, firm painful cords, and functional testing to assess peripheral occlusive arterial disease or identify superficial and deep venous reflux of the legs. Knowledge of differential diagnosis is essential for ensuring treatment success in patients with leg ulcer. There are many possible etiologic factors of leg ulcers and sometimes, clinical findings are similar. Additional testing should be performed, e.g., serologic testing such as blood count, C-reactive protein, HBA1c, erythrocyte sedimentation rate, differential blood count, total proteins, electrolytes, coagulation parameters, circulating immune complex, cryoglobulins, homocysteins, AT, PAI-1, APC resistance, proteins C and S, paraproteins, ANA, ENA, ANCA, dsDNA, antiphospholipid antibodies, urea, creatinine, blood lipids, vitamins and trace elements. Also, biopsy of the lesion for histopathology, direct immunofluorescence, bacteriology and mycology should be included. Other tests are Raynaud (cold stimulation) test and pathergy test. Device-based diagnostic testing should be performed for future

  15. Foot, leg, and ankle swelling

    MedlinePlus

    ... feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... 51. Trayes KP, Studdiford JS, Pickle S, Tully AS. Edema: Diagnosis and management. Am Fam Phys . 2013;88( ...

  16. Other Causes of Leg Pain

    MedlinePlus

    ... Past Issues Special Section Other Causes of Leg Pain Past Issues / Summer 2008 Table of Contents For ... a crowd of people walking. Photo: iStock Leg pain can come from a variety of causes. Your ...

  17. Correction of Thermal Gradient Errors in Stem Thermocouple Hygrometers

    PubMed Central

    Michel, Burlyn E.

    1979-01-01

    Stem thermocouple hygrometers were subjected to transient and stable thermal gradients while in contact with reference solutions of NaCl. Both dew point and psychrometric voltages were directly related to zero offset voltages, the latter reflecting the size of the thermal gradient. Although slopes were affected by absolute temperature, they were not affected by water potential. One hygrometer required a correction of 1.75 bars water potential per microvolt of zero offset, a value that was constant from 20 to 30 C. PMID:16660685

  18. Correction of thermal gradient errors in stem thermocouple hygrometers.

    PubMed

    Michel, B E

    1979-01-01

    Stem thermocouple hygrometers were subjected to transient and stable thermal gradients while in contact with reference solutions of NaCl. Both dew point and psychrometric voltages were directly related to zero offset voltages, the latter reflecting the size of the thermal gradient. Although slopes were affected by absolute temperature, they were not affected by water potential. One hygrometer required a correction of 1.75 bars water potential per microvolt of zero offset, a value that was constant from 20 to 30 C. PMID:16660685

  19. Revision of the standard reference data for thermocouples.

    NASA Technical Reports Server (NTRS)

    Powell, R. L.

    1972-01-01

    Revision of the International Practical Temperature Scale requires that there be changes for all accurately tabulated thermophysical values. Revised reference data for thermocouples have been generated in a program carried out by the National Bureau of Standards. The new reference data reflect not only revisions in the temperature scale, but also slight changes in the materials themselves and improvements in data fitting methods. A new NBS monograph that contains tables, analytic expressions, various approximations, and explanatory text has been prepared. A general discussion of the project and some specific examples are given.

  20. Summary of Thermocouple Performance During Advanced Gas Reactor Fuel Irradiation Experiments in the Advanced Test Reactor and Out-of-Pile Thermocouple Testing in Support of Such Experiments

    SciTech Connect

    A. J. Palmer; DC Haggard; J. W. Herter; M. Scervini; W. D. Swank; D. L. Knudson; R. S. Cherry

    2011-07-01

    High temperature gas reactor experiments create unique challenges for thermocouple based temperature measurements. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time dependent change in composition and, as a consequence, a time dependent drift of the thermocouple signal. This drift is particularly severe for high temperature platinum-rhodium thermocouples (Types S, R, and B); and tungsten-rhenium thermocouples (Types C and W). For lower temperature applications, previous experiences with type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly type N thermocouples are expected to be only slightly affected by neutron fluxes. Currently the use of these Nickel based thermocouples is limited when the temperature exceeds 1000°C due to drift related to phenomena other than nuclear irradiation. High rates of open-circuit failure are also typical. Over the past ten years, three long-term Advanced Gas Reactor (AGR) experiments have been conducted with measured temperatures ranging from 700oC – 1200oC. A variety of standard Type N and specialty thermocouple designs have been used in these experiments with mixed results. A brief summary of thermocouple performance in these experiments is provided. Most recently, out of pile testing has been conducted on a variety of Type N thermocouple designs at the following (nominal) temperatures and durations: 1150oC and 1200oC for 2000 hours at each temperature, followed by 200 hours at 1250oC, and 200 hours at 1300oC. The standard Type N design utilizes high purity crushed MgO insulation and an Inconel 600 sheath. Several variations on the standard Type N design were tested, including Haynes 214 alloy sheath, spinel (MgAl2O4) insulation instead of MgO, a customized sheath developed at the University of Cambridge, and finally a loose assembly thermocouple with hard fired alumina

  1. Acute Effects of Normobaric Hypoxia on Hand-Temperature Responses During and After Local Cold Stress

    PubMed Central

    Kölegård, Roger; Mekjavic, Igor B.; Eiken, Ola

    2014-01-01

    Abstract Keramidas, Michail E, Roger Kölegård, Igor B. Mekjavic, and Ola Eiken. Acute effects of normobaric hypoxia on hand-temperature responses during and after local cold stress. High Alt Med Biol. 15:183–191, 2014.—The purpose was to investigate acute effects of normobaric hypoxia on hand-temperature responses during and after a cold-water hand immersion test. Fifteen males performed two right-hand immersion tests in 8°C water, during which they were inspiring either room air (Fio2: 0.21; AIR), or a hypoxic gas mixture (Fio2: 0.14; HYPO). The tests were conducted in a counterbalanced order and separated by a 1-hour interval. Throughout the 30-min cold-water immersion (CWI) and the 15-min spontaneous rewarming (RW) phases, finger-skin temperatures were measured continuously with thermocouple probes; infrared thermography was also employed during the RW phase to map all segments of the hand. During the CWI phase, the average skin temperature (Tavg) of the fingers did not differ between the conditions (AIR: 10.2±0.5°C, HYPO: 10.0±0.5°C; p=0.67). However, Tavg was lower in the HYPO than the AIR RW phase (AIR: 24.5±3.4°C; HYPO: 22.0±3.8°C; p=0.002); a response that was alike in all regions of the immersed hand. Accordingly, present findings suggest that acute exposure to normobaric hypoxia does not aggravate the cold-induced drop in hand temperature of normothermic males. Still, hypoxia markedly impairs the rewarming responses of the hand. PMID:24666109

  2. Temporary Thermocouple Attachment for Thermal/Vacuum Testing at Non-Extreme Temperatures

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Wright, Sarah E.

    2016-01-01

    Post-test examination and data analysis that followed a two week long vacuum test showed that numerous self-stick thermocouples became detached from the test article. The thermocouples were reattached with thermally conductive epoxy and the test was repeated to obtain the required data. Because the thermocouple detachment resulted in significant expense and rework, it was decided to investigate the temporary attachment methods used around NASA and to perform a test to assess their efficacy. The present work describes the original test and the analysis that showed that the thermocouples had become detached, temporary thermocouple attachment methods assessed in the retest and in the thermocouple attachment test, and makes a recommendation for attachment methods for future tests.

  3. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  4. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature. PMID:16662241

  5. High Temperature Irradiation-Resistant Thermocouple Performance Improvements

    SciTech Connect

    Joshua Daw; Joy Rempe; Darrell Knudson; John Crepeau; S. Curtis Wilkins

    2009-04-01

    Traditional methods for measuring temperature in-pile degrade at temperatures above 1100 ºC. To address this instrumentation need, the Idaho National Laboratory (INL) developed and evaluated the performance of a high temperature irradiation-resistant thermocouple (HTIR-TC) that contains alloys of molybdenum and niobium. Data from high temperature (up to 1500 ºC) long duration (up to 4000 hours) tests and on-going irradiations at INL’s Advanced Test Reactor demonstrate the superiority of these sensors to commercially-available thermocouples. However, several options have been identified that could further enhance their reliability, reduce their production costs, and allow their use in a wider range of operating conditions. This paper presents results from on-going Idaho National Laboratory (INL)/University of Idaho (UI) efforts to investigate options to improve HTIR-TC ductility, reliability, and resolution by investigating specially-formulated alloys of molybdenum and niobium and alternate diameter thermoelements (wires). In addition, on-going efforts to evaluate alternate fabrication approaches, such as drawn and loose assembly techniques will be discussed. Efforts to reduce HTIR-TC fabrication costs, such as the use of less expensive extension cable will also be presented. Finally, customized HTIR-TC designs developed for specific customer needs will be summarized to emphasize the varied conditions under which these sensors may be used.

  6. Heat flux measurements on ceramics with thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Holanda, Raymond; Anderson, Robert C.; Liebert, Curt H.

    1993-01-01

    Two methods were devised to measure heat flux through a thick ceramic using thin film thermocouples. The thermocouples were deposited on the front and back face of a flat ceramic substrate. The heat flux was applied to the front surface of the ceramic using an arc lamp Heat Flux Calibration Facility. Silicon nitride and mullite ceramics were used; two thicknesses of each material was tested, with ceramic temperatures to 1500 C. Heat flux ranged from 0.05-2.5 MW/m2(sup 2). One method for heat flux determination used an approximation technique to calculate instantaneous values of heat flux vs time; the other method used an extrapolation technique to determine the steady state heat flux from a record of transient data. Neither method measures heat flux in real time but the techniques may easily be adapted for quasi-real time measurement. In cases where a significant portion of the transient heat flux data is available, the calculated transient heat flux is seen to approach the extrapolated steady state heat flux value as expected.

  7. Restless legs syndrome.

    PubMed

    Klingelhoefer, Lisa; Bhattacharya, Kalyan; Reichmann, Heinz

    2016-08-01

    Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is a common movement disorder characterised by an uncontrollable urge to move because of uncomfortable, sometimes painful sensations in the legs with a diurnal variation and a release with movement. The pathophysiology is only partially known and a genetic component together with dopaminergic and brain iron dysregulation plays an important role. Secondary causes for RLS need to be excluded. Treatment depends on the severity and frequency of RLS symptoms, comprises non-pharmacological (eg lifestyle changes) and pharmacological interventions (eg dopaminergic medication, alpha-2-delta calcium channel ligands, opioids) and relieves symptoms only. Augmentation is the main complication of long-term dopaminergic treatment of RLS. This article will provide a clinically useful overview of RLS with provision of diagnostic criteria, differential diagnoses, possible investigations and different treatment strategies with their associated complications. PMID:27481386

  8. ORTHOPEDIC LEG BRACE

    NASA Technical Reports Server (NTRS)

    Myers, William Neil (Inventor)

    2005-01-01

    Knee braces generally have been rigid in both the knee bending direction and in the knee straightening direction unless a manually operated release is incorporated in them to allow the knee to bend. Desirably a braced knee joint should effectively duplicate the compound, complex, actions of a normal knee. The key to knee braces is the knee joint housing. The housing herein carries a number of cam action pawls. with teeth adapted to engage the internal teeth of a ratchet ring mounted in the housing. Cam action return springs and the shape of the cam action pawl teeth allow rotation of the ratchet ring in a leg straightening direction while still supporting a load. The leg can then be extended during walking while at the same time being prevented by the cam action pawls from buckling in the knee bending direction.

  9. Spot weld attachment of thermocouples to a fuel rod cladding interior surface

    SciTech Connect

    Page, R.E.; Bates, S.O.; Pilger, J.P.

    1984-08-01

    Research was conducted by Pacific Northwest Laboratory to weld 0.020-inch-diameter thermocouples to the interior surface of Zircaloy 4 light-water reactor fuel cladding. Inconel sheathed Type K thermocouples were attached to fuel cladding to register cladding temperatures during loss-of-coolant accident testing. This report describes the development of welding parameters and the effects of thermocouple attachment on the burst strength and integrity of the cladding at temperatures up to 1550/sup 0/F.

  10. Thin-Film Thermocouple Technology Demonstrated for Reliable Heat Transfer Measurements

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Exploratory work is in progress to apply thin-film thermocouples to localized heat transfer measurements on turbine engine vanes and blades. The emerging thin-film thermocouple technology shows great potential to improve the accuracy of local heat transfer measurements. To verify and master the experimental methodology of thin-film thermocouples, the NASA Lewis Research Center conducted a proof-of-concept experiment in a controlled environment before applying the thin-film sensors to turbine tests.

  11. Study of performance characteristics of noble metal thermocouple materials to 2000 C

    NASA Technical Reports Server (NTRS)

    Freeze, P. D.; Thomas, D.; Edelman, S.; Stern, J.

    1972-01-01

    Three performance characteristics of noble metal thermocouples in various environments are discussed. Catalytic effects cause significant errors when noble metal thermocouple materials are exposed to air containing unburned gases in temperature ranges from 25 C to 1500 C. The thermoelectric stability of the iridium 40 rhodium to iridium thermocouple system at 2000 C in an oxidizing medium is described. The effects of large and small temperature gradients on the accuracy and stability of temperature measurements are analyzed.

  12. Venous Leg Ulcers.

    PubMed

    Vivas, Alejandra; Lev-Tov, Hadar; Kirsner, Robert S

    2016-08-01

    This issue provides a clinical overview of venous leg ulcers, focusing on prevention, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers. PMID:27479227

  13. Pt/Pd thermocouple resilience over 327 operating hours in an industrial calibration laboratory

    NASA Astrophysics Data System (ADS)

    Elliott, C. J.; Pearce, J. V.; Machin, G.; Ford, T.; Hicks, K.

    2013-09-01

    Two Pt/Pd thermocouples have been manufactured industrially at CCPI-Europe to a robust design optimised by NPL. The first has been exposed to temperatures up to 1000 °C for 93 operating hours and the second exposed to higher temperatures (up to 1300 °C) for 327 operating hours, over the course of a year. No significant drift is observed in the temperature measurement for either Pt/Pd thermocouple, when compared against reference Type R thermocouples. This work demonstrates the long-term stability and reliability of Pt/Pd thermocouples in use within an industrial calibration environment with this optimised, robust design.

  14. Cold Sores

    MedlinePlus

    ... delivered directly to your desktop! more... What Are Cold Sores? Article Chapters What Are Cold Sores? Cold ... January 2012 Previous Next Related Articles: Canker and Cold Sores Aloe Vera May Help Relieve Mouth Sores ...

  15. Leg size and muscle functions associated with leg compliance

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.; Doerr, Donald F.; Flores, Jose F.; Hoffler, G. Wyckliffe; Buchanan, Paul

    1988-01-01

    The relationship between the leg compliance and factors related to the size of leg muscle and to physical fitness was investigated in ten healthy subjects. Vascular compliance of the leg, as determined by a mercury strain gauge, was found to be not significantly correlated with any variables associated with physical fitness per se (e.g., peak O2 uptake, calf strength, age, body weight, or body composition. On the other hand, leg compliance correlated with the calf cross-sectional area (CSA) and the calculated calf volume, with the CSA of calf muscle being the most dominant contributing factor (while fat and bone were poor predicators). It is suggested that leg compliance can be lowered by increasing calf muscle mass, thus providing structural support to limit the expansion of leg veins.

  16. Differential diagnosis of leg ulcers.

    PubMed

    Pannier, F; Rabe, E

    2013-03-01

    Leg and foot ulcers are symptoms of very different diseases. The aim of this paper is to demonstrate the differential diagnosis of leg ulcers. The majority of leg ulcers occur in the lower leg or foot. In non-venous ulcers the localization in the foot area is more frequent. The most frequent underlying disease is chronic venous disease. In 354 leg ulcers, Koerber found 75.25% venous leg ulcers, 3.66% arterial leg ulcers, 14.66% ulcers of mixed venous and arterial origin and 13.5% vasculitic ulcers. In the Swedish population of Skaraborg, Nelzen found a venous origin in 54% of the ulcer patients. Each leg ulcer needs a clinical and anamnestic evaluation. Duplex ultrasound is the basic diagnostic tool to exclude vascular anomalies especially chronic venous and arterial occlusive disease. Skin biopsies help to find a correct diagnosis in unclear or non-healing cases. In conclusion, chronic venous disease is the most frequent cause of leg ulcerations. Because 25% of the population have varicose veins or other chronic venous disease the coincidence of pathological venous findings and ulceration is very frequent even in non-venous ulcerations. Leg ulcers without the symptoms of chronic venous disease should be considered as non-venous. PMID:23482536

  17. High-Temperature, Thin-Film Ceramic Thermocouples Developed

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2005-01-01

    To enable long-duration, more distant human and robotic missions for the Vision for Space Exploration, as well as safer, lighter, quieter, and more fuel efficient vehicles for aeronautics and space transportation, NASA is developing instrumentation and material technologies. The high-temperature capabilities of thin-film ceramic thermocouples are being explored at the NASA Glenn Research Center by the Sensors and Electronics Branch and the Ceramics Branch in partnership with Case Western Reserve University (CWRU). Glenn s Sensors and Electronics Branch is developing thin-film sensors for surface measurement of strain, temperature, heat flux, and surface flow in propulsion system research. Glenn s Ceramics Branch, in conjunction with CWRU, is developing structural and functional ceramic technology for aeropropulsion and space propulsion.

  18. Measurement of frequency response in short thermocouple wires

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Meeks, E. L.; Ma, J.

    1991-01-01

    Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decreas the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

  19. Reference data for thermocouple materials below the ice point.

    NASA Technical Reports Server (NTRS)

    Sparks, L. L.; Powell, R. L.

    1972-01-01

    Standard thermoelectric data have been determined for four thermocouple combinations used below the ice point: commercial types E, K, and T and the special combination of KP vs Au-0.07 at.% Fe. Power series coefficients necessary to generate E = f(T) data for these combinations are given. In addition, extensive tests were carried out to ascertain the variability between materials from different manufacturers. Typical wires processed for low-temperature usage often have slightly thermoelectric properties (up to 1%) from those, nominally identical, wires made for high-temperature applications. Generally, type E is the most satisfactory standardized commercial combination. The Au-0.07 at.% Fe material has been examined in particular detail, because it is not yet an ISA standard material. It has excellent sensitivity in the liquid helium/liquid hydrogen temperature range and a nearly linear thermovoltage at higher temperatures.

  20. Leg cramps and restless legs syndrome during pregnancy.

    PubMed

    Hensley, Jennifer G

    2009-01-01

    Sleep disturbance during pregnancy can result in excessive daytime sleepiness, diminished daytime performance, inability to concentrate, irritability, and the potential for an increased length of labor and increased risk of operative birth. Sleep disturbance may be the result of a sleep disorder, such as leg cramps, a common yet benign disorder, or restless legs syndrome, a sensorimotor disorder. Both disrupt sleep, are distressing to the pregnant woman, and mimic one another and other serious disorders. During pregnancy, up to 30% of women can be affected by leg cramps, and up to 26% can be affected by restless legs syndrome. PMID:19410213

  1. Exertional Leg Pain.

    PubMed

    Rajasekaran, Sathish; Finnoff, Jonathan T

    2016-02-01

    Exertional leg pain is a common condition seen in runners and the general population. Given the broad differential diagnosis of this complaint, this article focuses on the incidence, anatomy, pathophysiology, clinical presentation, diagnostic evaluation, and management of common causes that include medial tibial stress syndrome, tibial bone stress injury, chronic exertional compartment syndrome, arterial endofibrosis, popliteal artery entrapment syndrome, and entrapment of the common peroneal, superficial peroneal, and saphenous nerves. Successful diagnosis of these conditions hinges on performing a thorough history and physical examination followed by proper diagnostic testing and appropriate management. PMID:26616179

  2. Tension leg platform system

    SciTech Connect

    Burns, R.B.

    1983-12-20

    A tension leg platform system for use in drilling wellbores into the floor of an offshore body of water. Includes in the system is a buoyancy control vessel having a plurality of pull down cables attached thereto which extend to the ocean floor. A plurality of spaced apart anchors disposed at the ocean floor are positioned to receive the lower ends of the respective pull down cables. A submergible hull slidably engages the respective hold down cables such that the hull can be controllably lowered to the ocean floor whereby a canopy carried on the hull will cover an uncontrollably flowing well to conduct the effluent to the water's surface.

  3. High-temperature, long-term drift of platinum-rhodium thermocouples

    NASA Technical Reports Server (NTRS)

    Szaniszlo, A. J.

    1970-01-01

    Contamination of thermocouples is minimized by use of pure alumina insulators and a controlled low-impurity-level high-vacuum environment. Average thermal electromotive force change for platinum-rhodium thermocouples was -2.8 deg K after 3700 hours exposure to a mean temperature of 1530 deg K.

  4. Dynamic modeling and compensation of fine wire thermocouple based on rocket engine

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Liao, Guangxuan

    2001-08-01

    When transient temperature is measured by thermocouples, the result is largely influenced by thermocouple's dynamic performance. This problem is encountered in measuring flame temperature fluctuation by using of fine wire thermocouple. Because the heat transfer coefficient mostly depends upon the gas temperature and flow speed, the time constant of fine wire thermocouple is not equal in different temperature ranges. The time constant calibrated in low temperature is not valid in this kind of measurement. Typically frequency of fluctuation in flame is less than 7KHz. The fine wire thermocouple often has to be compensated to meet this working frequency band. The compensation range is determined by its time constant in high temperature. High temperature step source with sharp rise is needed in dynamic calibrating this kind of fine wire thermocouples. A dynamic calibration system based on a set of rocket engine and different propellant is introduced to study the dynamic performance of the thermocouples. This set of rocket engine is designed to have same nozzle exhaust Mach number. Different engines with different propellant provide different high temperature step sources. Experiment is conducted in rocket engine static state experiment laboratory. The position of thermocouple is determined according to numerical simulation results. Dynamic modeling and compensation methods are introduced to process the calibration results.

  5. Development of a Sheathed Miniature Aerothermal Reentry Thermocouple for Thermal Protection System Materials

    NASA Technical Reports Server (NTRS)

    Martinez, Edward R.; Weber, Carissa Tudryn; Oishi, Tomo; Santos, Jose; Mach, Joseph

    2011-01-01

    The Sheathed Miniature Aerothermal Reentry Thermocouple is a micro-miniature thermocouple for high temperature measurement in extreme environments. It is available for use in Thermal Protection System materials for ground testing and flight. This paper discusses the heritage, and design of the instrument. Experimental and analytical methods used to verify its performance and limitations are described.

  6. Modeling and control of thermocouples for reduced measurement uncertainty in diffusion furnaces

    NASA Astrophysics Data System (ADS)

    Yelverton, Mark E.; McBride, Michael J.

    2000-08-01

    Thermocouples are a widely used sensor in Semiconductor manufacturing because of their relatively low cost and ease of use. Most users in an attempt to improve measurement accuracy, purchase pre-calibrated thermocouples and establish replacement or re-calibration schedules. Unfortunately, these processes are often not based on actual thermocouple drift data, but most likely base don historical practice, opinion, or misinformation. This paper addresses the simple, but often misunderstood physics behind how thermocouples 'feel' temperature, and models the various sources of error that can occur with this sensor. Using this information, this paper outlines a procedure for ensuring accurate measurement in a production environment. The electronics used to convert the thermocouple signal to a temperature is discussed, along with how thermocouples are calibrated and why in-situ calibration in the field is not practical. Sources of measurement error are modeled including incoming calibration error, manual data-entry error of calibration data, tool or electronically induced error, and drift over time. These sources of error are described and modeled for 'type R' thermocouples, the most widely used thermocoupled for high temperature diffusion applications, using over five years of manufacturing data from over 70 horizontal and vertical diffusion furnaces.

  7. Refractory oxide insulated thermocouple designed and analyzed for high temperature applications

    NASA Technical Reports Server (NTRS)

    Popper, G. F.; Zeren, T. Z.

    1969-01-01

    Study establishes design criteria for constructing high temperature thermocouple to measure nuclear fuel pin temperature. The study included a literature search to determine the compatibility of material useful for thermocouples, a hot zone error analysis, and a prototype design for hot junction and connector pin connections.

  8. Structural evaluation of thermocouple probes for 241-AZ-101 waste tank

    SciTech Connect

    Kanjilal, S.K.

    1994-12-06

    This document reports on the structural analysis of the thermocouple probe to be installed in 241-AZ-101 waste tank. The thermocouple probe is analyzed for normal pump mixing operation and potential earthquake induced loads required by the Hanford Site Design Criteria SDC-4.1.

  9. Method of preventing leakage of a fluid along and through an insulating jacket of a thermocouple

    DOEpatents

    Thermos, Anthony Constantine; Rahal, Fadi Elias

    2002-01-01

    A thermocouple assembly includes a thermocouple; a plurality of lead wires extending from the thermocouple; an insulating jacket extending along and enclosing the plurality of leads; and at least one internally sealed area within the insulating jacket to prevent fluid leakage along and within the insulating jacket. The invention also provides a method of preventing leakage of a fluid along and through an insulating jacket of a thermocouple including the steps of a) attaching a plurality of lead wires to a thermocouple; b) adding a heat sensitive pseudo-wire to extend along the plurality of lead wires; c) enclosing the lead wires and pseudo-wire inside an insulating jacket; d) locally heating axially spaced portions of the insulating jacket to a temperature which melts the pseudo-wire and fuses it with an interior surface of the jacket.

  10. Thermocouples fabricated on trench sidewall in microfluidic channel bonded with film cover

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Takahiro; Shibata, Masahiro; Kumagai, Shinya; Sasaki, Minoru

    2015-03-01

    Thermocouples on a trench sidewall fronting a flow are fabricated by three-dimensional (3D) photolithography. The conventional thermocouples on the wafer top surface are also fabricated. The performances of these devices are compared. Without the flow inside the microchannel, the thermocouple on the trench sidewall shows the same output voltage as that on the wafer top surface positioned 40 µm from the channel. As a static response, when the microchannel is heated and room-temperature air flows inside the channel, the thermocouple on the sidewall shows a lower voltage. As a dynamic response, when hot air flows inside the channel and replaces the room-temperature air, the thermocouple on the sidewall shows a faster response, increasing its output voltage, and the local temperature of the flow can be measured more precisely.

  11. Investigation of factors affecting the heater wire method of calibrating fine wire thermocouples

    NASA Technical Reports Server (NTRS)

    Keshock, E. G.

    1972-01-01

    An analytical investigation was made of a transient method of calibrating fine wire thermocouples. The system consisted of a 10 mil diameter standard thermocouple (Pt, Pt-13% Rh) and an 0.8 mil diameter chromel-alumel thermocouple attached to a 20 mil diameter electrically heated platinum wire. The calibration procedure consisted of electrically heating the wire to approximately 2500 F within about a seven-second period in an environment approximating atmospheric conditions at 120,000 feet. Rapid periodic readout of the standard and fine wire thermocouple signals permitted a comparison of the two temperature indications. An analysis was performed which indicated that the temperature distortion at the heater wire produced by the thermocouple junctions appears to be of negligible magnitude. Consequently, the calibration technique appears to be basically sound, although several practical changes which appear desirable are presented and discussed. Additional investigation is warranted to evaluate radiation effects and transient response characteristics.

  12. The reliability of calibration for thermocouples in industry at around 1300 °C

    NASA Astrophysics Data System (ADS)

    Ogura, H.; Numajiri, H.; Kobayashi, T.

    2013-09-01

    Recently, the eutectic points are being studied by many national institutes, and considered being useful for the calibration laboratories in industry to improve their uncertainty of thermocouple calibration at high temperature. To conduct a cooperative research for investigation on the reliability of thermocouple calibration in industry at high temperature, a working group has been established within the Japan Society for the Promotion of Science (JSPS). AIST and nine domestic laboratories participated to this working group. In this working group, thermocouple comparison measurements were performed at around 1300 °C in nine laboratories by using two Pt/Pd thermocouples and one type R thermocouple following calibration at Co-C eutectic point. It was found that the uncertainties of calibration at around 1300°C in industry would be improved by utilizing the calibration at Co-C eutectic point.

  13. Lifetime improvement of sheathed thermocouples for use in high-temperature and thermal transient operations

    SciTech Connect

    McCulloch, R.W.; Clift, J.H.

    1982-01-01

    Premature failure of small-diameter, magnesium-oxide-insulated sheathed thermocouples occurred when they were placed within nuclear fuel rod simulators (FRSs) to measure high temperatures and to follow severe thermal transients encountered during simulation of nuclear reactor accidents in Oak Ridge National Laboratory (ORNL) thermal-hydraulic test facilities. Investigation of thermally cycled thermocouples yielded three criteria for improvement of thermocouple lifetime: (1) reduction of oxygen impurities prior to and during their fabrication, (2) refinement of thermoelement grain size during their fabrication, and (3) elimination of prestrain prior to use above their recrystallization temperature. The first and third criteria were satisfied by improved techniques of thermocouple assembly and by a recovery anneal prior to thermocouple use.

  14. Maneuvers during legged locomotion

    NASA Astrophysics Data System (ADS)

    Jindrich, Devin L.; Qiao, Mu

    2009-06-01

    Maneuverability is essential for locomotion. For animals in the environment, maneuverability is directly related to survival. For humans, maneuvers such as turning are associated with increased risk for injury, either directly through tissue loading or indirectly through destabilization. Consequently, understanding the mechanics and motor control of maneuverability is a critical part of locomotion research. We briefly review the literature on maneuvering during locomotion with a focus on turning in bipeds. Walking turns can use one of several different strategies. Anticipation can be important to adjust kinematics and dynamics for smooth and stable maneuvers. During running, turns may be substantially constrained by the requirement for body orientation to match movement direction at the end of a turn. A simple mathematical model based on the requirement for rotation to match direction can describe leg forces used by bipeds (humans and ostriches). During running turns, both humans and ostriches control body rotation by generating fore-aft forces. However, whereas humans must generate large braking forces to prevent body over-rotation, ostriches do not. For ostriches, generating the lateral forces necessary to change movement direction results in appropriate body rotation. Although ostriches required smaller braking forces due in part to increased rotational inertia relative to body mass, other movement parameters also played a role. Turning performance resulted from the coordinated behavior of an integrated biomechanical system. Results from preliminary experiments on horizontal-plane stabilization support the hypothesis that controlling body rotation is an important aspect of stable maneuvers. In humans, body orientation relative to movement direction is rapidly stabilized during running turns within the minimum of two steps theoretically required to complete analogous maneuvers. During straight running and cutting turns, humans exhibit spring-mass behavior in the

  15. Common cold

    MedlinePlus

    ... are the most common reason that children miss school and parents miss work. Parents often get colds ... other children. A cold can spread quickly through schools or daycares. Colds can occur at any time ...

  16. Common Cold

    MedlinePlus

    ... coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In ... people in the United States suffer 1 billion colds. You can get a cold by touching your ...

  17. Cold Stress

    MedlinePlus

    ... be at risk of cold stress. Extreme cold weather is a dangerous situation that can bring on ... the country. In regions relatively unaccustomed to winter weather, near freezing temperatures are considered factors for cold ...

  18. Cold intolerance

    MedlinePlus

    ... intolerance is an abnormal sensitivity to a cold environment or cold temperatures. ... can be a symptom of a problem with metabolism. Some people (often very thin women) do not tolerate cold environments because they have very little body fat and ...

  19. A System for High-Temperature Homogeneity Scanning of Noble-Metal Thermocouples

    NASA Astrophysics Data System (ADS)

    Webster, E.; Mason, R.; Greenen, A.; Pearce, J.

    2015-11-01

    Noble-metal thermocouples are amongst the most widely used thermocouples for high-temperature process measurement and as references. Although they are less susceptible to inhomogeneity effects than the more-common base-metal thermocouples, inhomogeneity is still the major source of uncertainty. Currently, most estimates of the uncertainty due to inhomogeneity are based on thermocouple specifications or historical performance of similar thermocouples. It is not common for the inhomogeneity to be measured directly, in part because there is no accepted method for measuring the inhomogeneities, and in part because there is no conclusive evidence linking the magnitude of inhomogeneities determined at the scanning temperature to the effects of the same inhomogeneities at other temperatures. This paper describes an inhomogeneity scanner able to be fitted to sodium heat-pipe furnaces to operate between 600°C and 1000°C. Comparison of scans made at 100°C demonstrates the scalability of some types of inhomogeneity in Type S and R thermocouples. It is concluded that for Type R and S thermocouples, a robust uncertainty assessment can be obtained from a scan made at a single temperature.

  20. Contact Thermocouple Methodology and Evaluation for Temperature Measurement in the Laboratory

    NASA Technical Reports Server (NTRS)

    Brewer, Ethan J.; Pawlik, Ralph J.; Krause, David L.

    2013-01-01

    Laboratory testing of advanced aerospace components very often requires highly accurate temperature measurement and control devices, as well as methods to precisely analyze and predict the performance of such components. Analysis of test articles depends on accurate measurements of temperature across the specimen. Where possible, this task is accomplished using many thermocouples welded directly to the test specimen, which can produce results with great precision. However, it is known that thermocouple spot welds can initiate deleterious cracks in some materials, prohibiting the use of welded thermocouples. Such is the case for the nickel-based superalloy MarM-247, which is used in the high temperature, high pressure heater heads for the Advanced Stirling Converter component of the Advanced Stirling Radioisotope Generator space power system. To overcome this limitation, a method was developed that uses small diameter contact thermocouples to measure the temperature of heater head test articles with the same level of accuracy as welded thermocouples. This paper includes a brief introduction and a background describing the circumstances that compelled the development of the contact thermocouple measurement method. Next, the paper describes studies performed on contact thermocouple readings to determine the accuracy of results. It continues on to describe in detail the developed measurement method and the evaluation of results produced. A further study that evaluates the performance of different measurement output devices is also described. Finally, a brief conclusion and summary of results is provided.

  1. Field installed brazed thermocouple feedthroughs for high vacuum experiments

    NASA Astrophysics Data System (ADS)

    Anderson, P. M.; Messick, C.

    1983-12-01

    In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer O ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs were used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: (1) melting temperature in excess of the 250 C (482 F) bakeout temperature; (2) no high vapor pressure elements; (3) good wetting properties when used in air with acceptable flux; and (4) good wettability to 300 series stainless steel and Inconel.

  2. Calibration of thermocouple psychrometers and moisture measurements in porous materials

    NASA Astrophysics Data System (ADS)

    Guz, Łukasz; Sobczuk, Henryk; Połednik, Bernard; Guz, Ewa

    2016-07-01

    The paper presents in situ method of peltier psychrometric sensors calibration which allow to determine water potential. Water potential can be easily recalculated into moisture content of the porous material. In order to obtain correct results of water potential, each probe should be calibrated. NaCl salt solutions with molar concentration of 0.4M, 0.7M, 1.0M and 1.4M, were used for calibration which enabled to obtain osmotic potential in range: -1791 kPa to -6487 kPa. Traditionally, the value of voltage generated on thermocouples during wet-bulb temperature depression is calculated in order to determine the calibration function for psychrometric in situ sensors. In the new method of calibration, the field under psychrometric curve along with peltier cooling current and duration was taken into consideration. During calibration, different cooling currents were applied for each salt solution, i.e. 3, 5, 8 mA respectively, as well as different cooling duration for each current (from 2 to 100 sec with 2 sec step). Afterwards, the shape of each psychrometric curve was thoroughly examined and a value of field under psychrometric curve was computed. Results of experiment indicate that there is a robust correlation between field under psychrometric curve and water potential. Calibrations formulas were designated on the basis of these features.

  3. Leg or foot amputation - dressing change

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000018.htm Leg or foot amputation - dressing change To use the sharing features ... chap 16. Read More Compartment syndrome Leg or foot amputation Peripheral artery disease - legs Type 1 diabetes ...

  4. Measurement and simulation of thermoelectric efficiency for single leg.

    PubMed

    Hu, Xiaokai; Yamamoto, Atsushi; Ohta, Michihiro; Nishiate, Hirotaka

    2015-04-01

    Thermoelectric efficiency measurements were carried out on n-type bismuth telluride legs with the hot-side temperature at 100 and 150°C. The electric power and heat flow were measured individually. Water coolant was utilized to maintain the cold-side temperature and to measure heat flow out of the cold side. Leg length and vacuum pressure were studied in terms of temperature difference across the leg, open-circuit voltage, internal resistance, and heat flow. Finite-element simulation on thermoelectric generation was performed in COMSOL Multiphysics, by inputting two-side temperatures and thermoelectric material properties. The open-circuit voltage and resistance were in good agreement between the measurement and simulation. Much larger heat flows were found in measurements, since they were comprised of conductive, convective, and radiative contributions. Parasitic heat flow was measured in the absence of bismuth telluride leg, and the conductive heat flow was then available. Finally, the maximum thermoelectric efficiency was derived in accordance with the electric power and the conductive heat flow. PMID:25933893

  5. Measurement and simulation of thermoelectric efficiency for single leg

    SciTech Connect

    Hu, Xiaokai; Yamamoto, Atsushi Ohta, Michihiro; Nishiate, Hirotaka

    2015-04-15

    Thermoelectric efficiency measurements were carried out on n-type bismuth telluride legs with the hot-side temperature at 100 and 150°C. The electric power and heat flow were measured individually. Water coolant was utilized to maintain the cold-side temperature and to measure heat flow out of the cold side. Leg length and vacuum pressure were studied in terms of temperature difference across the leg, open-circuit voltage, internal resistance, and heat flow. Finite-element simulation on thermoelectric generation was performed in COMSOL Multiphysics, by inputting two-side temperatures and thermoelectric material properties. The open-circuit voltage and resistance were in good agreement between the measurement and simulation. Much larger heat flows were found in measurements, since they were comprised of conductive, convective, and radiative contributions. Parasitic heat flow was measured in the absence of bismuth telluride leg, and the conductive heat flow was then available. Finally, the maximum thermoelectric efficiency was derived in accordance with the electric power and the conductive heat flow.

  6. Investigations of Thermocouple Drift Irregularity Impact on Error of their Inhomogeneity Correction

    NASA Astrophysics Data System (ADS)

    Jun, Su; Kochan, Orest

    2014-02-01

    The article examines: (i) the reasons of error due to thermoelectric inhomogeneity of electrodes of thermocouples acquired during prolonged use; (ii) the neural network method of error correction based on a generalization of verification results in several temperature fields; (iii) the method of investigating the impact of changing the speed of the conversion characteristic drift of thermocouple on error correction; (iv) results of this investigation. It is shown that residual error for type K thermocouples at the 5 % level of significance does not exceed μ±0.46 oС and one at the 10 % level of significance does not exceed ±0.25 °С

  7. Pressurized water nuclear reactor system with hot leg vortex mitigator

    SciTech Connect

    Lau, L.K.S.

    1990-09-18

    This patent describes an improvement in a pressurized water nuclear reactor system having a reactor pressure vessel, at least one steam generator, a hot leg conduit for charging of hot fluid from the reactor pressure vessel to the steam generator, and at least one cold leg conduit for return of cool fluid from the steam generator back to the reactor pressure vessel. The improvement comprises a residual heat removal device wherein: the hot leg has an inside diameter D{sub 1}; a first section of residual heat removal conduit is provided, having an inside diameter D{sub 2}, a first end for receipt of fluid from the hot leg, and a second end; a second section of residual heat removal conduit is provided connected to the reactor pressure vessel; a pump interconnects the second end of the first section of residual heat removal conduit with the second section of residual heat removal conduit; and a step nozzle of an inside diameter D{sub 3} and a length L interconnects the hot leg to the first end of the first section of residual heat removal conduit, with D{sub 3}/D{sub 1} {ge} 0.55, with D{sub 3}/D{sub 2}1.9 and L/D{sub 3} {ge} 1.44.

  8. Getting Your Sea Legs

    PubMed Central

    Stoffregen, Thomas A.; Chen, Fu-Chen; Varlet, Manuel; Alcantara, Cristina; Bardy, Benoît G.

    2013-01-01

    Sea travel mandates changes in the control of the body. The process by which we adapt bodily control to life at sea is known as getting one's sea legs. We conducted the first experimental study of bodily control as maritime novices adapted to motion of a ship at sea. We evaluated postural activity (stance width, stance angle, and the kinematics of body sway) before and during a sea voyage. In addition, we evaluated the role of the visible horizon in the control of body sway. Finally, we related data on postural activity to two subjective experiences that are associated with sea travel; seasickness, and mal de debarquement. Our results revealed rapid changes in postural activity among novices at sea. Before the beginning of the voyage, the temporal dynamics of body sway differed among participants as a function of their (subsequent) severity of seasickness. Body sway measured at sea differed among participants as a function of their (subsequent) experience of mal de debarquement. We discuss implications of these results for general theories of the perception and control of bodily orientation, for the etiology of motion sickness, and for general phenomena of perceptual-motor adaptation and learning. PMID:23840560

  9. Attachment of Free Filament Thermocouples for Temperature Measurements on CMC

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

    1997-01-01

    Ceramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.

  10. Exercise training using arms and legs versus legs along.

    PubMed

    Mostardi, R A; Gandee, R N; Norris, W A

    1981-07-01

    This study was undertaken to determine whether levels of conditioning associated with conventional leg work are comparable to those associated with both arm and leg work. Six healthy men conditioned for 6 weeks using both arms and legs while a similar group of 5 men conditioned using legs alone. The subjects trained 3 times per week on a bicycle ergometer, and covered a distance of 3 miles (4.83 km) per session using interval training techniques. Oxygen consumption (VO2) and heart rate (HR) were the primary comparative measures. There were no differences in improvement of maximal aerobic power between the 2 groups. However, the arm and leg subjects were able to do more work at a lower HR during the conditioning program. This implies considerably less physical stress on the heart and skeletal muscle, and indicates that the feeling of stress is related to metabolic rate per square area of working muscle rather than to total metabolism. Since this type of conditioning provides high levels of improvement in aerobic power wit less demands on the myocardium, it is suggested that arm and leg exercise be incorporated in the rehabilitation of cardiac patients. PMID:7247660

  11. Options to Extend the Applicability of High Temperature Irradiation Resistant Thermocouples

    SciTech Connect

    Joy L. Rempe; Darrell L. Knudson; Keith G. Condie; S. Curtis Wilkins; John C. Crepeau; Joshua E. Daw; Patrick J. Green

    2007-09-01

    Several options have been identified that could further enhance the reliability and increase the applicability of recently developed Idaho National Laboratory (INL) High Temperature Irradiation Resistant thermocouples (HTIR-TCs) for in-pile testing, allowing their use in higher temperature applications (up to at least 1700 °C). INL and the University of Idaho (UI) are investigating these options with the ultimate objective of providing recommendations for alternate thermocouple designs that are optimized for various applications. This paper reports the status of INL/UI investigations. Results are reported from tests completed to evaluate the ductility, resolution, transient response, and stability of thermocouples made from specially formulated alloys of molybdenum and niobium. In addition, this paper reports preliminary insights gained by comparing the performance of thermocouples fabricated with various heat treatments and alternate geometries.

  12. Long Duration Testing of Type C Thermocouples at 1500 °C

    SciTech Connect

    Joy L. Rempe; Darrell L. Knudson; J. E. Daw; S. C. Wilkins

    2008-04-01

    Experience with Type C thermocouples operating for long periods in the 1400 to 1600 °C temperature range indicate that significant decalibration occurs, often leading to expensive downtime and material waste. As part of an effort to understand the mechanisms causing drift in these thermocouples, the Idaho National Laboratory conducted a long duration test at 1500 °C containing eight Type C thermocouples. As report in this document, results from this long duration test were adversely affected due to oxygen ingress. Nevertheless, results provide key insights about the impact of precipitate formation on thermoelectric response. Post-test examinations indicate that thermocouple signal was not adversely impacted by the precipitates detected after 1,000 hours of heating at 1,500 °C and suggest that the signal would not have been adversely impacted by these precipitates for longer durations (if oxygen ingress had not occurred in this test).

  13. Options Extending the Applicability of High-Temperature Irradiation-Resistant Thermocouples

    SciTech Connect

    Joy L. Rempe; Darrell L. Knudson; Keith G. Condie; John C. Crepeau; Joshua E. Daw

    2009-07-01

    Several options have been identified that could further enhance the reliability and extend the applicability of High Temperature Irradiation Resistant ThermoCouples (HTIR-TCs) developed by the Idaho National Laboratory (INL) for in-pile testing, allowing their use in temperature applications as high as 1800 °C. The INL and the University of Idaho (UI) investigated these options with the ultimate objective of providing recommendations for alternate thermocouple designs that are optimized for various applications. This paper reports results from INL/UI investigations. Results are reported from tests completed to evaluate the ductility, resolution, transient response, and stability of thermocouples made from specially formulated alloys of molybdenum and niobium. In addition, this paper reports insights gained by comparing the performance of thermocouples fabricated with various heat treatments and alternate geometries.

  14. Design and Operation of a Fast, Thin-Film Thermocouple Probe on a Turbine Engine

    NASA Technical Reports Server (NTRS)

    Meredith, Roger D.; Wrbanek, John D.; Fralick, Gustave C.; Greer, Lawrence C., III; Hunter, Gary W.; Chen, Liang-Yu

    2014-01-01

    As a demonstration of technology maturation, a thin-film temperature sensor probe was fabricated and installed on a F117 turbofan engine via a borescope access port to monitor the temperature experienced in the bleed air passage of the compressor area during an engine checkout test run. To withstand the harsh conditions experienced in this environment, the sensor probe was built from high temperature materials. The thin-film thermocouple sensing elements were deposited by physical vapor deposition using pure metal elements, thus avoiding the inconsistencies of sputter-depositing particular percentages of materials to form standardized alloys commonly found in thermocouples. The sensor probe and assembly were subjected to a strict protocol of multi-axis vibrational testing as well as elevated temperature pressure testing to be qualified for this application. The thin-film thermocouple probe demonstrated a faster response than a traditional embedded thermocouple during the engine checkout run.

  15. Thermocouples calibration and analysis of the influence of the length of the sensor coating

    NASA Astrophysics Data System (ADS)

    Noriega, M.; Ramírez, R.; López, R.; Vaca, M.; Morales, J.; Terres, H.; Lizardi, A.; Chávez, S.

    2015-01-01

    This paper presents the design and construction of a lab prototype, with a much lower cost compared to the ones commercially sold, enabling the manufacture of thermocouples which are then calibrated to verify their functionality and acceptance. We also analyze the influence of the external insulation over the wires, to determine whether it influences temperature measurement. The tested lengths ranged from 0.00 m up to 0.030 m. The thermocouple was compared against the behavior of a thermocouple of the same type that was purchased with a commercial supplier. The obtained measurement showed less than 1 °C difference in some points. This makes the built thermocouple reliable, since the standard allows a difference of up to 2.2 °C.

  16. Temperature field acquisition during gas metal arc welding using thermocouples, thermography and fibre Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Moreira, P. M. G. P.; Frazão, O.; Tavares, S. M. O.; de Figueiredo, M. A. V.; Restivo, M. T.; Santos, J. L.; de Castro, P. M. S. T.

    2007-03-01

    The paper presents the application of temperature acquisition systems integrating thermocouples, a thermographic camera and fibre Bragg grating (FBG) sensors in gas metal arc welding (GMAW) process, MIG (metal inert gas) welding type. Efficient procedures to use FBG sensors and thermocouples were developed. The paper presents and compares measurements made in welded plates of aluminium alloy 6082-T6. Tests were performed in both plate surfaces and good agreement between the three techniques was found.

  17. Film Thickness Influences on the Thermoelectric Properties of NiCr/NiSi Thin Film Thermocouples

    NASA Astrophysics Data System (ADS)

    Chen, Y. Z.; Jiang, H. C.; Zhang, W. L.; Liu, X. Z.; Jiang, S. W.

    2013-06-01

    NiCr/NiSi thin film thermocouples (TFTCs) with a multi-layer structure were fabricated on Ni-based superalloy substrates (95 mm × 35 mm × 2 mm) by magnetron sputtering and electron beam evaporation. The five-layer structure is composed of NiCrAlY buffer layer (2 μm), thermally grown Al2O3 bond layer (200 nm), Al2O3 insulating layer (10 μm), NiCr/NiSi TFTCs (1 μm), and Al2O3 protective layer (500 nm). Influences of thermocouple layer thickness on thermoelectric properties were investigated. Seebeck coefficient of the samples with the increase in thermocouple layer thickness from 0.5 μm to 1 μm increased from 27.8 μV/°C to 33.8 μV/°C, but exhibited almost no change with further increase in thermocouple layer thickness from 1 μm to 2 μm. Dependence on temperature of the thermal electromotive force of the samples almost followed standard thermocouple characteristic curves when the thickness of the thermocouple layer was 1 μm and 2 μm. Sensitive coefficient K of the samples increased greatly with the increase in thickness of the thermocouple layer from 0.5 μm to 1 μm, but decreased insignificantly with the increase in thermocouple layer thickness from 1 μm to 2 μm, and continuously decreased with the increase in temperature. The sensitive coefficient and the stability of NiCr/NiSi TFTCs were both improved after annealing at 600°C.

  18. Thermocouple module halt failure acceptance test procedure for Tank 241-SY-101 DACS-1

    SciTech Connect

    Ermi, A.M.

    1997-12-09

    The readiness of the Tank 241-SY-101 Data Acquisition and Control System (DACS-1) to provide monitoring and alarms for a halt failure of any thermocouple module will be tested during the performance of this procedure. Updated DACS-1 ``1/0 MODULE HEALTH STATUS``, ``MININ1``, and ``MININ2`` screens, which now provide indication of thermocouple module failure, will also be tested as part of this procedure.

  19. Restless leg syndrome in pregnancy.

    PubMed

    Grover, Aarti; Clark-Bilodeau, Courtney; D'Ambrosio, Carolyn M

    2015-09-01

    Restless leg syndrome, more recently renamed Willis-Ekbom disease, is a condition that disrupts sleep and occurs more frequently in the pregnant population. We present a 39-year-old woman with restless legs syndrome in the third trimester and discuss the epidemiology, pathophysiology and therapeutic options in the pregnant population while highlighting the challenges posed by the lack of safety data of approved drugs. PMID:27512466

  20. High reliability sheathed, beryllia insulated, tungsten-rhenium alloy thermocouple assemblies; their fabrication and EMF stability

    NASA Technical Reports Server (NTRS)

    Burns, G. W.; Hurst, W. S.; Scroger, M. G.

    1974-01-01

    Tantalum sheathed, BeO insulated, W-3% Re/W-25% Re thermocouple assemblies were fabricated and their emf drift determined during 2059 hours of exposure at 2073 K in a gaseous helium environment. The sheathed thermocouple assemblies were constructed from aged thermoelements, specially heat-treated BeO insulators, and specially cleaned and etched tantalum sheaths. Their thermal emf drifts ranged from the equivalent of only -0.3 to -0.8 K drift per 1000 hours of exposure at 2073 K. No evidence of any gross chemical attack or degradation of the component materials was found. The emf drift and material behavior of some unsheathed, BeO insulated, W-3% Re/W-25% Re thermocouples at 2250 and 2400 K were also determined. Unsheathed thermocouples tested in an argon environment at 2250 K for 1100 hours and at 2400 K for 307 hours exhibited changes in thermal emf that typically ranged from the equivalent of a few degrees K to as much as +11 K. Post-test examinations of these thermocouples revealed some undesirable material degradation and interaction which included erosion of the BeO insulators and contamination of the thermoelements by tantalum from the tantalum blackbody enclosure in which the thermocouples were contained.

  1. An Evaluation of the PBF LOFT Lead Rod Test Results Concerning Surface Thermocouple Perturbation Effects

    SciTech Connect

    M. L. Carboneau E. L. Tolman

    1980-02-08

    The purpose of the Power Burst Facility Loss of Fluid Test (PBF LOFT) Lead Rod (LLR) Test program was to provide experimental data to characterize the mechanical behavior of LOFT type nuclear fuel rods under loss of coolant accident (LOCA) conditions, simulating the test conditions expected for the LOFT Power Ascension (L2) Test series. Although the LLR tests were not explicitly designed to evaluate cladding surface thermocouple perturbation effects, comparison of the Linear Variable Differential Transformer (LVDT) data for rods instrumented with and without cladding thermocouples provided pertinent information concerning the effects of cladding thermocouples on the time to DNB and time to quench data. Documentation and review of this data is presented in the following report. It will be shown that most of the LLR data indicate that the cladding surface thermocouples did not enhance the rewetting characteristics of the rods they are attached to, even though other evidence shows that the surface clad thermocouples did quench early. Finally, in order to accurately interpret and understand the limitations of the LVDT instrumentation, upon which thermocouple perturbation effects were evaluated, an analysis of the LVDT data as well as a review of the atypical response events that occurred during the LLR tests are presented in appendices to this document.

  2. Thermocouples in an alternating magnetic field (AMF) for studying magnetic nanoparticle hyperthermia

    NASA Astrophysics Data System (ADS)

    Hartzell, S.; Boekelheide, Z.

    Magnetic nanoparticle hyperthermia, a method of cancer therapy, is currently a subject of active research. A critical parameter during therapy or laboratory research is the temperature of the system (tissue or nanoparticle suspension). Thermocouples are affordable and ubiquitous temperature sensors which could be used in this capacity; however, their metallic nature results in self-heating due to eddy currents when placed in an AMF. This presentation will quantitatively discuss calculations and measurements of the self-heating of three common types of thermocouples. Type T, K, and E thermocouples of both thin (40 gauge) and thick (20 gauge) wires were tested in a range of applied magnetic field magnitudes (235 kHz, 0-0.4 T rms). Among the thermocouples, all three types demonstrated large self-heating in 20 gauge wires. For the 40 gauge wires, type K showed large self-heating, while type T showed small but significant self-heating and type E showed no significant self-heating in comparison to the background. Our results indicate that thin type E thermocouples can be accurately used as temperature sensors in an AMF environment similar to the one used here, and type T thermocouples may be appropriate under conditions with lower magnetic field strength or frequency.

  3. INITIAL RESULTS FROM INVESTIGATIONS TO ENHANCE THE PERFORMANCE OF HIGH TEMPERATURE IRRADIATION-RESISTANT THERMOCOUPLES

    SciTech Connect

    Crepeau, John; Rempe, Joy; Wilkins, S. Curtis; Knudson, Darrell L.; Condie, Keith G.; Daw, Joshua

    2007-04-01

    New fuel, cladding, and structural materials offer the potential for safer and more economic energy from existing reactor and advanced nuclear reactor designs. However, insufficient data are available to characterize these materials in high temperature, radiation conditions. To evaluate candidate material performance, robust instrumentation is needed that can survive these conditions. However, traditional thermocouples either drift due to degradation at high temperatures (above 1100 °C) or due to transmutation of thermocouple components. Thermocouples are needed which can withstand both high temperature and high radiation environments. To address this instrumentation need, the Idaho National Laboratory (INL) recently developed the design and evaluated the performance of a high temperature radiation-resistant thermocouple that contains commercially-available alloys of molybdenum and niobium (Rempe, 2006). Candidate thermocouple component materials were first identified based on their ability to withstand high temperature and radiation. Then, components were selected based on data obtained from materials interaction tests, ductility investigations, and resolution evaluations. Results from long duration (over 4000 hours) tests at high temperatures (up to 1400 °C) and thermal cycling tests demonstrate the stability and reliability of the INL-developed design. Tests in INL’s Advanced Test Reactor (ATR) are underway to demonstrate the in-pile performance of these thermocouples. However, several options have been identified that could further enhance the lifetime and reliability of the INL-developed thermocouples, allowing their use in higher temperature applications (up to at least 1700 °C). A joint University of Idaho (UI) and INL University Nuclear Energy Research Initiative (UNERI) is underway to investigate these options and ultimately, provide recommendations for an enhanced thermocouple design. This paper presents preliminary results from this UI/INL effort

  4. Restless Legs Syndrome and Leg Motor Restlessness in Parkinson's Disease

    PubMed Central

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-01-01

    Sleep disturbances are important nonmotor symptoms in Parkinson's disease (PD) that are associated with a negative impact on quality of life. Restless legs syndrome (RLS), which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR), which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders. PMID:26504610

  5. Common Cold

    MedlinePlus

    ... News & Events Volunteer NIAID > Health & Research Topics > Common Cold Skip Website Tools Website Tools Print this page ... Help people who are suffering from the common cold by volunteering for NIAID clinical studies on ClinicalTrials. ...

  6. Popliteal artery entrapment syndrome: a common cause of a rare clinical entity--critical leg ischemia in the young.

    PubMed

    Tsilogianni, Zoi; Grapatsas, Konstantinos; Papanikolaou, Zisis; Kokkini-Paschou, Aggeliki; Tsantilas, Apostolos; Tsiligiris, Vasileios; Vourliotakis, Georgios

    2014-01-01

    Popliteal artery entrapment syndrome (PAES) is a rare but important cause of leg ischemia and even disability in young athletes. Entrapment occurs because of an abnormal relationship between the popliteal artery and the surrounding muscular structures in the popliteal fossa. These anomalies lead to decreased blood flow to the affected leg with signs of claudication, coldness, and symptoms of exercise-induced leg pain. In this article, we present a case of a young soldier who presented with the above signs and symptoms in his left foot after exercise. On questioning, he admitted to having chronic lower leg pain. He was diagnosed with PAES in both legs and he was emergently treated with an arterial bypass procedure in the left one. He had no postoperative complications. PAES should be considered in the differential diagnosis of chronic or acute lower leg pain in any young patient. Early diagnosis and treatment can prevent limb loss and lead to a good operative outcome. PMID:24402998

  7. Beam localization in HIFU temperature measurements using thermocouples, with application to cooling by large blood vessels.

    PubMed

    Dasgupta, Subhashish; Banerjee, Rupak K; Hariharan, Prasanna; Myers, Matthew R

    2011-02-01

    Experimental studies of thermal effects in high-intensity focused ultrasound (HIFU) procedures are often performed with the aid of fine wire thermocouples positioned within tissue phantoms. Thermocouple measurements are subject to several types of error which must be accounted for before reliable inferences can be made on the basis of the measurements. Thermocouple artifact due to viscous heating is one source of error. A second is the uncertainty regarding the position of the beam relative to the target location or the thermocouple junction, due to the error in positioning the beam at the junction. This paper presents a method for determining the location of the beam relative to a fixed pair of thermocouples. The localization technique reduces the uncertainty introduced by positioning errors associated with very narrow HIFU beams. The technique is presented in the context of an investigation into the effect of blood flow through large vessels on the efficacy of HIFU procedures targeted near the vessel. Application of the beam localization method allowed conclusions regarding the effects of blood flow to be drawn from previously inconclusive (because of localization uncertainties) data. Comparison of the position-adjusted transient temperature profiles for flow rates of 0 and 400ml/min showed that blood flow can reduce temperature elevations by more than 10%, when the HIFU focus is within a 2mm distance from the vessel wall. At acoustic power levels of 17.3 and 24.8W there is a 20- to 70-fold decrease in thermal dose due to the convective cooling effect of blood flow, implying a shrinkage in lesion size. The beam-localization technique also revealed the level of thermocouple artifact as a function of sonication time, providing investigators with an indication of the quality of thermocouple data for a given exposure time. The maximum artifact was found to be double the measured temperature rise, during initial few seconds of sonication. PMID:20817250

  8. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, William T.

    1992-01-01

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler.

  9. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, W.T.

    1992-06-16

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long as a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler. 8 figs.

  10. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  11. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  12. Prometheus Hot Leg Piping Concept

    NASA Astrophysics Data System (ADS)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  13. Intramuscular pressures beneath elastic and inelastic leggings

    NASA Technical Reports Server (NTRS)

    Murthy, G.; Ballard, R. E.; Breit, G. A.; Watenpaugh, D. E.; Hargens, A. R.

    1994-01-01

    Leg compression devices have been used extensively by patients to combat chronic venous insufficiency and by astronauts to counteract orthostatic intolerance following spaceflight. However, the effects of elastic and inelastic leggings on the calf muscle pump have not been compared. The purpose of this study was to compare in normal subjects the effects of elastic and inelastic compression on leg intramuscular pressure (IMP), an objective index of calf muscle pump function. IMP in soleus and tibialis anterior muscles was measured with transducer-tipped catheters. Surface compression between each legging and the skin was recorded with an air bladder. Subjects were studied under three conditions: (1) control (no legging), (2) elastic legging, and (3) inelastic legging. Pressure data were recorded for each condition during recumbency, sitting, standing, walking, and running. Elastic leggings applied significantly greater surface compression during recumbency (20 +/- 1 mm Hg, mean +/- SE) than inelastic leggings (13 +/- 2 mm Hg). During recumbency, elastic leggings produced significantly higher soleus IMP of 25 +/- 1 mm Hg and tibialis anterior IMP of 28 +/- 1 mm Hg compared to 17 +/- 1 mm Hg and 20 +/- 2 mm Hg, respectively, generated by inelastic leggings and 8 +/- 1 mm Hg and 11 +/- 1 mm Hg, respectively, without leggings. During sitting, walking, and running, however, peak IMPs generated in the muscular compartments by elastic and inelastic leggings were similar. Our results suggest that elastic leg compression applied over a long period in the recumbent posture may impede microcirculation and jeopardize tissue viability.(ABSTRACT TRUNCATED AT 250 WORDS).

  14. Assessment of tungsten/rhenium thermocouples with metal-carbon eutectic fixed points up to 1500°C

    SciTech Connect

    Gotoh, M.

    2013-09-11

    Four Type A thermocouples and two Type C thermocouples were calibrated at the Au fixed point and Co-C and Pd-C eutectic fixed points. The thermocouples were exposed to 1330 °C for a total of 100 hours. The maximum drift due to the exposure was found to be 4.8 °C. The fixed-point calibration EMF of these thermocouples deviated by less than 0.86% from the temperature specified by the standards ASTM E230-2003 for Type C and GOSTR 8.585-2001 for Type A. The length of one of Type A thermocouples A52 is longer than the others by 150mm. Making use of this provision it was possible to place annealed part of A52 to the temperature gradient part of calibration arrangement every time. Therefore observed aging effect was as low as 0.5 °C compared to the other thermocouples.

  15. Noncatalytic thermocouple coatings produced with chemical vapor deposition for flame temperature measurements.

    PubMed

    Bahlawane, N; Struckmeier, U; Kasper, T S; Osswald, P

    2007-01-01

    Chemical vapor deposition (CVD) and metal-organic chemical vapor deposition (MOCVD) have been employed to develop alumina thin films in order to protect thermocouples from catalytic overheating in flames and to minimize the intrusion presented to the combustion process. Alumina films obtained with a CVD process using AlCl(3) as the precursor are dense, not contaminated, and crystallize in the corundum structure, while MOCVD using Al(acetyl acetone)(3) allows the growth of corundum alumina with improved growth rates. These films, however, present a porous columnar structure and show some carbon contamination. Therefore, coated thermocouples using AlCl(3)-CVD were judged more suitable for flame temperature measurements and were tested in different fuels over a typical range of stoichiometries. Coated thermocouples exhibit satisfactory measurement reproducibility, no temporal drifts, and do not suffer from catalytic effects. Furthermore, their increased radiative heat loss (observed by infrared spectroscopy) allows temperature measurements over a wider range when compared to uncoated thermocouples. A flame with a well-known temperature profile established with laser-based techniques was used to determine the radiative heat loss correction to account for the difference between the apparent temperature measured by the coated thermocouple and the true flame temperature. The validity of the correction term was confirmed with temperature profile measurements for several flames previously studied in different laboratories with laser-based techniques. PMID:17503931

  16. Features of High-Temperature Calibration of W/Re Thermocouples

    NASA Astrophysics Data System (ADS)

    Ulanovskiy, A.; Edler, F.; Fischer, J.; Oleynikov, P.; Zaytsev, P.; Pokhodun, A.

    2015-03-01

    Investigations of Type A (W-5 %Re/W-20 %Re) thermocouples were performed at several laboratories to validate their reference function before its standardization in the new issue of the international standard IEC 60584. The Type A thermocouples investigated were equipped with sealed protection tubes made of sapphire which were filled with an inert gas (argon). The investigations at Russian laboratories were performed mainly in carbon-free high-temperature furnaces. The calibration results obtained in the temperature range (600 to 1850) in the carbon-free environment were within % tolerance limits and confirmed the suitability of Type A thermocouples for industrial applications. In contrast, the Type A thermocouple 89/95-P investigated at PTB (Germany) was exposed to a carbon environment when annealed at and when it was calibrated at metal-carbon eutectic (Me-C) fixed points. Measurements made at Me-C fixed points did not deviate from the reference function by more than about 6 K at the first stage when temperatures were below . However, the inhomogeneity of the thermoelements increased continuously after the calibration at the Me-C eutectic fixed points. The additional measurements at the peritectic fixed point () resulted in a continuous emf drift to deviations from the reference function of about (100 to 150) which corresponds to a temperature equivalent of about (9 to 14) K. The thermoelectric stability and homogeneity of the thermocouple 89/95-P during these investigations was checked by repeated measurements at the freezing point of copper ().

  17. Noncatalytic thermocouple coatings produced with chemical vapor deposition for flame temperature measurements

    NASA Astrophysics Data System (ADS)

    Bahlawane, N.; Struckmeier, U.; Kasper, T. S.; Oßwald, P.

    2007-01-01

    Chemical vapor deposition (CVD) and metal-organic chemical vapor deposition (MOCVD) have been employed to develop alumina thin films in order to protect thermocouples from catalytic overheating in flames and to minimize the intrusion presented to the combustion process. Alumina films obtained with a CVD process using AlCl3 as the precursor are dense, not contaminated, and crystallize in the corundum structure, while MOCVD using Al(acetylwidth="0.3em"/>acetone)3 allows the growth of corundum alumina with improved growth rates. These films, however, present a porous columnar structure and show some carbon contamination. Therefore, coated thermocouples using AlCl3-CVD were judged more suitable for flame temperature measurements and were tested in different fuels over a typical range of stoichiometries. Coated thermocouples exhibit satisfactory measurement reproducibility, no temporal drifts, and do not suffer from catalytic effects. Furthermore, their increased radiative heat loss (observed by infrared spectroscopy) allows temperature measurements over a wider range when compared to uncoated thermocouples. A flame with a well-known temperature profile established with laser-based techniques was used to determine the radiative heat loss correction to account for the difference between the apparent temperature measured by the coated thermocouple and the true flame temperature. The validity of the correction term was confirmed with temperature profile measurements for several flames previously studied in different laboratories with laser-based techniques.

  18. HYPERTENSIVE-ISCHEMIC LEG ULCERS

    PubMed Central

    Farber, Eugene M.; Schmidt, Otto E. L.

    1950-01-01

    Ischemic ulcers of the leg having characteristics different from those of ordinary leg ulcers have been observed in a small number of hypertensive patients, mostly women, during the past few years. Such ulcers are usually located above the ankle. They begin with a small area of purplish discoloration at the site of slight trauma, and progress to acutely tender ulceration. In studies of tissue removed from the margin and the base of an ulcer of this kind, obliterative arteriolar sclerotic changes, ischemic-appearing connective tissue and inflammatory changes were noted. Two additional cases are reported. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:15398887

  19. Development of ac Calorimetric Method for Thermal Diffusivity Measurement I. Contribution of Thermocouple Attachment in a Thin Sample

    NASA Astrophysics Data System (ADS)

    Hatta, Ichiro; Kato, Ryozo; Maesono, Akikazu

    1986-06-01

    In a very thin sample, the contribution of addenda, thermocouple, glue etc., to the precise measurement is considered especially in two typical cases, in which the thermocouple is attached to the sample surface using glue. In the one case, glue is painted over the whole one-sided region starting from the thermocouple on the surface and in the other, a small amount of glue is used to fix the thermocouple at a particular point on the surface. Consistent with the theoretical consideration, it is experimentally verified in both cases that the addenda do not affect determination of the thermal diffusivity.

  20. Printed organic conductive polymers thermocouples in textile and smart clothing applications.

    PubMed

    Seeberg, Trine M; Røyset, Arne; Jahren, Susannah; Strisland, Frode

    2011-01-01

    This work reports on an experimental investigation of the potential of using selected commercially available organic conductive polymers as active ingredients in thermocouples printed on textiles. Poly(3, 4-ethylenedioxythiophene): poly(4 styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI) were screen printed onto woven cotton textile. The influence of multiple thermocycles between 235 K (-38 °C) and 350 K (+77 °C) on resistivity and thermoelectric properties was examined. The Seebeck coefficients of PEDOT:PSS and PANI were found to be about +18 μV/K and +15 uV/K, respectively, when "metal-polymer" thermocouples were realized by combining the polymer with copper. When "polymer-polymer" thermocouples were formed by combining PEDOT:PSS and PANI, a thermoelectric voltage of about +10 μV/K was observed. A challenge recognized in the experiments is that the generated voltage exhibited drift and fluctuations. PMID:22255039

  1. Thermocouple protection systems for longer service life in slagging gasifier environments

    SciTech Connect

    Kwong, Kyei-Sing; Chinn, Richard E.; Iverson, Larissa A.; Bennett, James P.; Dogan, Cynthia P.

    2003-01-01

    To ensure reliable and efficient operation, gasifier operators would like to be able to continuously monitor system temperature. In many slagging gasifiers, temperature measurement is accomplished by several thermocouples embedded at various locations in the gasifier wall. Unfortunately, these thermocouple devices are very susceptible to early failure, either as the result of mechanical stresses or exposure to the harsh slagging environment, making long-term continuous temperature monitoring difficult. At the Albany Research Center, we are developing strategies to improve the ceramic protection assembly that is used to shield the thermocouple wires from direct exposure to the gasifier atmosphere. In this talk we will describe this multi-component ceramic protection system and present test results, which indicate that, the protection system should provide longer device service life in slagging gasifier environments.

  2. Prototype thin-film thermocouple/heat-flux sensor for a ceramic-insulated diesel engine

    NASA Technical Reports Server (NTRS)

    Kim, Walter S.; Barrows, Richard F.

    1988-01-01

    A platinum versus platinum-13 percent rhodium thin-film thermocouple/heat-flux sensor was devised and tested in the harsh, high-temperature environment of a ceramic-insulated, low-heat-rejection diesel engine. The sensor probe assembly was developed to provide experimental validation of heat transfer and thermal analysis methodologies applicable to the insulated diesel engine concept. The thin-film thermocouple configuration was chosen to approximate an uninterrupted chamber surface and provide a 1-D heat-flux path through the probe body. The engine test was conducted by Purdue University for Integral Technologies, Inc., under a DOE-funded contract managed by NASA Lewis Research Center. The thin-film sensor performed reliably during 6 to 10 hr of repeated engine runs at indicated mean surface temperatures up to 950 K. However, the sensor suffered partial loss of adhesion in the thin-film thermocouple junction area following maximum cyclic temperature excursions to greater than 1150 K.

  3. Frequency response of a supported thermocouple wire: Effects of axial conduction

    NASA Technical Reports Server (NTRS)

    Forney, L. J.; Meeks, E. L.; Fralick, G. C.

    1991-01-01

    Theoretical expressions are derived for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire and a two material wire with unequal material properties across the junction. For the case of a one material supported wire, an exact solution is derived which compares favorably with an approximate expression that only matches temperatures at the support junction. Moreover, for the case of a two material supported wire, an analytical expression is derived that closely correlates numerical results. Experimental data were taken with a type K supported thermocouple. The test thermocouple was constructed with dimensions to demonstrate the effects of axial heat conduction assuming constant physical properties across the junction.

  4. Mixing Hot and Cold Water Streams at a T-Junction

    ERIC Educational Resources Information Center

    Sharp, David; Zhang, Mingqian; Xu, Zhenghe; Ryan, Jim; Wanke, Sieghard; Afacan, Artin

    2008-01-01

    A simple mixing of a hot- and cold-water stream at a T-junction was investigated. The main objective was to use mass and energy balance equations to predict mass low rates and the temperature of the mixed stream after the T-junction, and then compare these with the measured values. Furthermore, the thermocouple location after the T-junction and…

  5. Thermocouple Rakes for Measuring Boundary Layer Flows Extremely Close to Surface

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Blaha, Charles A.

    2001-01-01

    Of vital interest to aerodynamic researchers is precise knowledge of the flow velocity profile next to the surface. This information is needed for turbulence model development and the calculation of viscous shear force. Though many instruments can determine the flow velocity profile near the surface, none of them can make measurements closer than approximately 0.01 in. from the surface. The thermocouple boundary-layer rake can measure much closer to the surface than conventional instruments can, such as a total pressure boundary layer rake, hot wire, or hot film. By embedding the sensors (thermocouples) in the region where the velocity is equivalent to the velocity ahead of a constant thickness strut, the boundary-layer flow profile can be obtained. The present device fabricated at the NASA Glenn Research Center microsystem clean room has a heater made of platinum and thermocouples made of platinum and gold. Equal numbers of thermocouples are placed both upstream and downstream of the heater, so that the voltage generated by each pair at the same distance from the surface is indicative of the difference in temperature between the upstream and downstream thermocouple locations. This voltage differential is a function of the flow velocity, and like the conventional total pressure rake, it can provide the velocity profile. In order to measure flow extremely close to the surface, the strut is made of fused quartz with extremely low heat conductivity. A large size thermocouple boundary layer rake is shown in the following photo. The latest medium size sensors already provide smooth velocity profiles well into the boundary layer, as close as 0.0025 in. from the surface. This is about 4 times closer to the surface than the previously used total pressure rakes. This device also has the advantage of providing the flow profile of separated flow and also it is possible to measure simultaneous turbulence levels within the boundary layer.

  6. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient.

    PubMed

    Hindasageri, V; Vedula, R P; Prabhu, S V

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively. PMID:23464237

  7. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient

    NASA Astrophysics Data System (ADS)

    Hindasageri, V.; Vedula, R. P.; Prabhu, S. V.

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively.

  8. Other Causes of Leg Pain

    MedlinePlus

    ... in the same position for a long time Injuries caused by: A torn or overstretched muscle (strain) Hairline crack in the bone (stress fracture) Inflamed tendon (tendinitis) Shin splints—pain in the front of your leg related to overuse or repetitive pounding Deep vein thrombosis (DVT) , which occurs when ...

  9. Rotational joint for prosthetic leg

    NASA Technical Reports Server (NTRS)

    Jones, W. C.; Owens, L. J.

    1977-01-01

    Device is installed in standard 30 millimeter tubing used for lower leg prosthetics. Unit allows proper rotation (about 3 degrees) of foot relative to the hip, during normal walking or running. Limited rotational movement with restoring force results in a more natural gait.

  10. Psychiatric Comorbidities in Restless Legs Syndrome.

    PubMed

    Kallweit, Ulf; Werth, Esther; Seiz, Angela; Sefidan, Sandra; Dahmen, Norbert; Manconi, Mauro; Ehlert, Ulrike; Bassetti, Claudio L A

    2016-01-01

    Restless legs syndrome (RLS) is a neurological sleep disorder with frequent (39%) coexisting psychiatric comorbidities. Patients with any psychiatric comorbidity had fewer periodic leg movements in sleep. Psychiatric disorders should be taken into account in patients with RLS. PMID:27019065