Sample records for constantan

  1. Biaxially Textured Constantan Alloy (Cu 55 wt%, Ni 44 wt%, Mn 1 wt%) Substrates for YBa2Cu3O7-x Coated Conductors (Postprint)

    DTIC Science & Technology


    deposit YBCO and other buffer layers using a Lambda Physic KrF (λ = 248 nm ) excimer laser. Typical processing parameters that were used for oxide...nearly 100 % as the annealing temperature of the rolled substrates was increased from 750 to 1200 ◦C. A full width half maximum (FWHM) of 6.5◦ in (111...phi scans and an FWHM of 4.9◦ in ( 100 ) omega scans were observed in the substrates annealed at 1200 ◦C for 2 h. These substrates were found to have a

  2. One-wire thermocouple

    NASA Technical Reports Server (NTRS)

    Goodrich, W. D.; Staimach, C. J.


    Nickel alloy/constantan device accurately measures surface temperature at precise locations. Device is moderate in cost and simplifies fabrication of highly-instrumented seamless-surface heat-transfer models. Device also applies to metal surfaces if constantan wire has insulative coat.

  3. High-Sensitivity Temperature Measurement

    ERIC Educational Resources Information Center

    Leadstone, G. S.


    Describes a method of measuring small temperature differences that amount to a .01K, using an arrangement of a copper-constantan thermocouple, a microamplifier and a galvanometer, as an indirect way of measuring heat energy. (GA)

  4. A hot probe setup for the measurement of Seebeck coefficient of thin wires and thin films using integral method.


    Kumar, S R Sarath; Kasiviswanathan, S


    An experimental setup is developed for the measurement of the Seebeck coefficient of thin wires and thin films in the temperature range of 300-650 K. The setup makes use of the integral method for measuring the Seebeck voltage across the sample. Two pointed copper rods with in-built thermocouples serve as hot and cold probes as well as leads for measuring the Seebeck voltage. The setup employs localized heating and enables easy sample loading using a spring loaded mounting system and is fully automated. Test measurements are made on a constantan wire and indium tin oxide (ITO) thin film for illustration. The Seebeck voltage obtained for constantan wire is in agreement with the NIST data for copper constantan couple with an error of 1%. The calculated carrier concentration of ITO film from the Seebeck coefficient measurement is comparable with that obtained by electrical transport measurements. The error in the Seebeck coefficient is estimated to be within 3%.

  5. A hot probe setup for the measurement of Seebeck coefficient of thin wires and thin films using integral method

    NASA Astrophysics Data System (ADS)

    Sarath Kumar, S. R.; Kasiviswanathan, S.


    An experimental setup is developed for the measurement of the Seebeck coefficient of thin wires and thin films in the temperature range of 300-650K. The setup makes use of the integral method for measuring the Seebeck voltage across the sample. Two pointed copper rods with in-built thermocouples serve as hot and cold probes as well as leads for measuring the Seebeck voltage. The setup employs localized heating and enables easy sample loading using a spring loaded mounting system and is fully automated. Test measurements are made on a constantan wire and indium tin oxide (ITO) thin film for illustration. The Seebeck voltage obtained for constantan wire is in agreement with the NIST data for copper constantan couple with an error of 1%. The calculated carrier concentration of ITO film from the Seebeck coefficient measurement is comparable with that obtained by electrical transport measurements. The error in the Seebeck coefficient is estimated to be within 3%.

  6. Laboratory Determination of Thermal Protection System Materials Surface Catalytic Properties

    DTIC Science & Technology


    using a variety of electrical discharge sources. Traditional methods of atom detection have included chemical titration,41 electron spin resonance...Probabilities Material Experiments γO, × 10-3 Quartz 11 0.098 ± 0.013 SS304 (Cr 18%, Ni 10%, Fe balance) 11 16 ± 7 Constantan (Ni 45%, Cu balance) 10 46...or b. Similar measurements with Inconel 617 at room temperature,76 and SS304 , Constantan, and Chromel at room temperature and 250 °C,68 also

  7. Experiments on Liquid Immersion Natural Convection Cooling of Leadless Chip Carriers Mounted on Ceramic Substrate

    DTIC Science & Technology


    Tfilm Average dielectric liquid 0C temperature TLC Thermochromic Liquid Crystal Dimensionless Tlid Average package lid temperature c TSE Temperature...the temperature sensitive Thermochromic Liquid Crystal (TLC). For additional thermal response measurement, nine Copper Constantan thermocouples of...heater assembly for Thermochromic Liquid Crystal (TLC) calibration. Approximately 1.27 centimeters diagonally from one of the corners, a 2.95

  8. STINGER Launch and Flight Motor Squib Electrical Safety and Functional Performance Evaluation

    DTIC Science & Technology


    equivalent electrostatic sensitivity. The circuit is a 3 nano - farad capacitor charged to 30 kilovolts with no resistor in series and then...conducted by placing a copper-constantan thermocouple referenced to a 0 C ice bath on an untested 105C squib case and encasing the squib in ground charcoal

  9. A thermocouple thermode for small animals

    NASA Technical Reports Server (NTRS)

    Williams, B. A.


    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.

  10. Investigation into Hydraulic Gear Pump Efficiencies during the First Few Hours of the Pumps’ Lives and a Comparative Study of Accelerated Life Test Methods on Hydraulic Fluid Power Gear Pumps. Parts 1 and 2.

    DTIC Science & Technology


    Institute Doug Gerber, Associate Technical Fellow, Fluid Power Institute Dave Jaccobuci, Associate Technical Fellow, Fluid Power Institute Harry Marquass...FLUID POtER INSTITUTE IIILWAUKE[ SCHOL OF [;iGI:1EERIIN j "LT Omega Iron- Constantan PROJECT ,jn. 50560 -- - . . ..hermocouple Calibration DAT.: 10

  11. Modern Thermocouple Experiment.

    ERIC Educational Resources Information Center

    Chang, K. N.; And Others


    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)

  12. Cavity Expansion Experiments with Spherical Explosive Charges in Concrete

    DTIC Science & Technology


    used to convert the recorded data to stress units. Although the vapor - deposited carbon element’s resistance is also sensitive to in-plane strain, its...manufacturing process is not compatible with vapor - depositing a companion constantan element, so strain was not monitored in those gages. The Dremin loop...4 Figure 3. Carbon and PVDF flatpacks

  13. Dynamic buckling behavior of thin metal film lines from substrate

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Xie, Huimin; Wang, Heling; Zhang, Jie; Li, Chuanwei


    The dynamic buckling behavior of thin films from substrate is studied in this work. The experimental results show that the buckling morphology of the constantan film lines from the polymer substrate is inconsistent and non-sinusoidal, which is different from the sinusoidal form of the buckling morphology under static loads. The plastic deformation of the film lines results in the non-sinusoidal buckling morphology and residual deformation when unloaded. Finite element modeling results with regard to the plastic dissipation of the constantan film lines reveal that the plastic dissipation suppresses the buckling-driven delaminating under impact loads. This study will give some new perspectives on the buckling behavior of thin film from substrate.

  14. Project SQUID: Quarterly Progress Report

    DTIC Science & Technology


    effect of mixing temperature upon the ignition lag of the bipropellant system, white fuming nitric acid and furfuryl alcohol , has been molecular activity with decreasing mixing temrerature and the poor mixing resulting from the marked increase in viscosity of the furfuryl alcohol ...micrometer mounted on the outside of the tubeo A traveling thermocouple constructed with No. 40B and S copper and constantan wires butt-welded together to

  15. Instrumentation and Techniques for the Measurement of Muscular Strength and Endurance in the Human Body

    DTIC Science & Technology


    Isometric-Isokinetic Torque Units 8 Isotonic Torque Units 8 Subject-Machine Couplings 10 Hand Grip and Plantar Flexor Ergometers 12 Electronic Processing of... Electronics (Waltham, MA) SR-4, constantan foil strain gauges which were attached to the bar at the point of maximal deflection close to the axis (B... Electronics Barrier E). These were coupled with resistors chosen so as to have an equal resistive value as the strain gauges. The resistors and strain

  16. Thermal and electrical properties of Evanohm and other resistance alloys below 4 K

    NASA Technical Reports Server (NTRS)

    Cieloszyk, G. S.; Cote, P. J.; Williams, J. C.; Salinger, G. L.


    Evanohm in the form of a fine wire is widely used in low-temperature experiments. It has a composition of 75% Ni, 20% Cr, 2.5% Cu, and 2.5% Al. The heat capacity of a rod of Evanohm was measured in the temperature range from 0.1 to 1.3 K. It was found that the specific heat of Evanohm does not display the increase found for constantan, manganin, and nichrome at low temperatures. Measurements of the thermal conductivity and the electrical and magnetic properties are also reported.

  17. Heat transfer tests of a 0.006-scale thin skin space shuttle model (50-0, 41-T) in the Langley Research Center nitrogen tunnel at Mach 19 (IH19)

    NASA Technical Reports Server (NTRS)

    Walstad, D. G.


    Data are presented from heat transfer tests on an 0.0006-scale space shuttle vehicle in the Langley Research Center Nitrogen Tunnel. The purpose of this test was to obtain ascent heating data at a high hypersonic Mach number. Configurations tested were integrated orbiter and external tank, orbiter alone, and external tank alone. All configurations were tested with and without boundary layer transition. Testing was conducted at a Mach number of 19, a Reynolds number of 0.5 million per foot, and angles of attack of 0, + or - 5, and + or - 10 degrees. Heat transfer data was obtained from 77 orbiter and 90 external tank iron-constantan thermocouples.

  18. Triple-material stress-strain resistivity gage


    Stout, R.B.


    A triple material piezoresistive gage provides multi-component elastic stress or strain measurements. Thin foils of three piezoresistive materials, e.g., ytterbium, manganin, and constantan, are configured in a nested serpentine rectilinear grind or other grind arrangement and embedded in a medium, preferably normal to the direction of shock wave propagation. The output of the gage is a resistivity change history for each material of gage. Each resistivity change is independent of the others so that three diagonal components of the elastic stress or strain tensor can be calculated form the resistivity measurements. 4 figs.

  19. Triple-material stress-strain resistivity gage


    Stout, Ray B.


    A triple material piezoresistive gage provides multi-component elastic stress or measurements. Thin foils of three piezoresistive materials, e.g. ytterbium, manganin, and constantan, are configured in a nested serpentine rectilinear grid or other grid arrangement and embedded in a medium, preferably normal to the direction of shock wave propagation. The output of the gage is a resistivity change history for each material of the gage. Each resistivity change is independent of the others so that three diagonal components of the elastic stress or strain tensor can be calculated from the resistivity measurements.

  20. Triple-material stress-strain resistivity gage


    Stout, R.B.


    A triple material piezoresistive gage provides multi-component elastic stress measurements is disclosed. Thin foils of three piezoresistive materials, e.g. ytterbium, manganin, and constantan, are configured in a nested serpentine rectilinear grid or other grid arrangement and embedded in a medium, preferably normal to the direction of shock wave propagation. The output of the gage is a resistivity change history for each material of the gage. Each resistivity change is independent of the others so that three diagonal components of the elastic stress or strain tensor can be calculated from the resistivity measurements. 4 figs.

  1. Multichannel temperature controller for hot air solar house

    NASA Technical Reports Server (NTRS)

    Currie, J. R.


    This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

  2. Theory and performance of plated thermocouples.

    NASA Technical Reports Server (NTRS)

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


    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.

  3. Developments in convective heat transfer models featuring seamless and selected detail surfaces, employing electroless plating

    NASA Technical Reports Server (NTRS)

    Stalmach, C. J., Jr.


    Several model/instrument concepts employing electroless metallic skin were considered for improvement of surface condition, accuracy, and cost of contoured-geometry convective heat transfer models. A plated semi-infinite slab approach was chosen for development and evaluation in a hypersonic wind tunnel. The plated slab model consists of an epoxy casting containing fine constantan wires accurately placed at specified surface locations. An electroless alloy was deposited on the plastic surface that provides a hard, uniformly thick, seamless skin. The chosen alloy forms a high-output thermocouple junction with each exposed constantan wire, providing means of determining heat transfer during tunnel testing of the model. A selective electroless plating procedure was used to deposit scaled heatshield tiles on the lower surface of a 0.0175-scale shuttle orbiter model. Twenty-five percent of the tiles were randomly selected and plated to a height of 0.001-inch. The purpose was to assess the heating effects of surface roughness simulating misalignment of tiles that may occur during manufacture of the spacecraft.

  4. [Influence of implants on human body during MRI examinations: fundamental experiment using metal balls].


    Muranaka, Hiroyuki; Nakamura, Osamu; Usui, Shuji; Ueda, Yoshitake; Morikawa, Kaoru


    It is increasingly the case that patients who have implants feel pain during high-field MRI examinations. A probable reason for the pain is the generation by irradiation of RF pulses and changing of the magnetic field gradient. As a fundamental study on the effect of implants on the human body under MRI procedures, temperature measurements were obtained from metal balls incorporated into gel-filled phantoms by using two kinds of measuring instruments, a copper-constantan thermocouple and a fluorescence fiber thermometer. At first we pursued a correlation between a copper-constantan thermocouple (absolute measurement) and fluoroptic thermometer and confirmed the precision and stability of the fluoroptic thermometer under MRI procedures. When a stainless steel ball with or without a loop antenna was used, only in the former case did the temperature rise during RF pulse irradiation. There was no significant difference between the magnetic field gradient ON and OFF. Furthermore, differences in metal (steel, aluminum, brass, stainless steel, copper) and size (5, 10, 20 mmPhi) were affected according to the increase of temperature. In conclusion, both RF pulse irradiation and a loop antenna are necessary for heat generation on the surface of metals.

  5. Experimental investigation of heat transfer in a rivulet on the inclined foil

    NASA Astrophysics Data System (ADS)

    Cheverda, V. V.; Marchuk, I. V.; Karchevsky, A. L.; Orlik, E. V.; Kabov, O. A.


    Heat transfer at rivulet water flow over the constantan foil with the length of 80 mm, width of 35 mm, and thickness of 25 mm was studied experimentally. The foil surface temperature was measured by an IR-scanner. Distributions of heat flux density on the surface of the foil, where the liquid flowed, were obtained. To determine the heat flux density from the foil to liquid near the contact line, the Cauchy problem was solved for the stationary heat equation using the thermographic data. Calculation results showed that the maximal heat flux occurs in the area of the contact line and exceeds the average heat flux from the entire foil surface by several times. This is explained by the influx of heat from the periphery of foil to the rivulet due to the relatively high value of heat conductivity coefficient of the foil material and high evaporation rate in the region of the contact line.

  6. Heat transfer tests of an 0.006-scale thin-skin space shuttle thermocouple model (41-OTS) in the Langley Research Center unitary plan wind tunnel at M equals 3.7 (IH16)

    NASA Technical Reports Server (NTRS)

    Walstad, D. G.


    The results are presented of supersonic heat transfer tests performed on the .006 scale space shuttle vehicle model (41-OTS) in the Langley Research Center Unitary Plan Wind Tunnel. These tests were conducted to parametrically investigate ascent heating of the integrated vehicle and its components. The tests were conducted at a nominal Mach number of 3.7 and Reynolds numbers per foot of 2 and 5 million. The model configurations investigated were the integrated vehicle and each component alone (i.e. orbiter, tank and SRB). All the configurations were run with and without transition strips and through an angle of attack range of 0 deg to minus 5 deg with the exception of the SRB which was tested through an angle of attack range of minus 5 deg to 90 deg. The heat transfer data were obtained from 223 iron constantan thermocouples attached to stainless steel thin-skin areas of the model.

  7. High Pressure and Temperature Effects on the Viscosity, Density, and Bulk Modulus of Four Liquid Lubricants.

    DTIC Science & Technology


    stainless—steel sheath which is silver— brazed to an air-quenched tool- steel plug. Six conductors, four iron and two constantan, are containec in the 0.63...intermittent short circuit between coils and had tr ~e rep laced . The new coil was heat treated and then pressure aged to minimize drift during...N cm cm —St —St C-~ C- ’ . SN C” ‘ -tO C —1 C..) —I N. -.1- cm r i U’ 0 ‘0 C ft (N cm U) N. N. cm. -ft -C U’ N. ‘0 N. — i f’ U’ Cl) El — U) —St U

  8. Thermocouple design for measuring temperatures of small insects.


    Hanson, A A; Venette, R C


    Contact thermocouples often are used to measure surface body temperature changes of insects during cold exposure. However, small temperature changes of minute insects can be difficult to detect, particularly during the measurement of supercooling points. We developed two thermocouple designs, which use 0.51 mm diameter or 0.127 mm diameter copper-constantan wires, to improve our ability to resolve insect exotherms. We tested the designs with adults from three parasitoid species: Tetrastichus planipennisi, Spathius agrili, and S. floridanus. These species are <3 mm long and <0.1 mg. Mean exotherms were greater for fine-gauge thermocouples than thick-gauge thermocouples for the smallest species tested, T. planipennisi. This difference was not apparent for larger species S. agrili and S. floridanus. Thermocouple design did not affect the mean supercooling point for any of the species. The cradle thermocouple design developed with the fine gauge wire was reusable and allowed for easy insect recovery after cold exposure.

  9. Surface Catalysis and Oxidation on Stagnation Point Heat Flux Measurements in High Enthalpy Arc Jets

    NASA Technical Reports Server (NTRS)

    Nawaz, Anuscheh; Driver, David M.; Terrazas-Salinas


    Heat flux sensors are routinely used in arc jet facilities to determine heat transfer rates from plasma plume. The goal of this study is to assess the impact of surface composition changes on these heat flux sensors. Surface compositions can change due to oxidation and material deposition from the arc jet. Systematic surface analyses of the sensors were conducted before and after exposure to plasma. Currently copper is commonly used as surface material. Other surface materials were studied including nickel, constantan gold, platinum and silicon dioxide. The surfaces were exposed to plasma between 0.3 seconds and 3 seconds. Surface changes due to oxidation as well as copper deposition from the arc jets were observed. Results from changes in measured heat flux as a function of surface catalycity is given, along with a first assessment of enthalpy for these measurements. The use of cupric oxide is recommended for future heat flux measurements, due to its consistent surface composition arc jets.

  10. Note: A sample holder design for sensitive magnetic measurements at high temperatures in a magnetic properties measurement system

    SciTech Connect

    Arauzo, A.; Guerrero, E.; Urtizberea, A.; Stankiewicz, J.; Rillo, C.


    A sample holder design for high temperature measurements in a commercial MPMS SQUID magnetometer from Quantum Design is presented. It fulfills the requirements for the simultaneous use of the oven and reciprocating sample option (RSO) options, thus allowing sensitive magnetic measurements up to 800 K. Alternating current susceptibility can also be measured, since the holder does not induce any phase shift relative to the ac driven field. It is easily fabricated by twisting Constantan Copyright-Sign wires into a braid nesting the sample inside. This design ensures that the sample be placed tightly into a tough holder with its orientation fixed, and prevents any sample displacement during the fast movements of the RSO transport, up to high temperatures.

  11. Heat transfer tests of an 0.006-scale thin-skin space shuttle model (41-OTS) in the Ames 3.5-foot HWT at M equals 5.3 (IH15)

    NASA Technical Reports Server (NTRS)

    Walstad, D. G.; Lockman, W. K.


    Data obtained from heat transfer tests of an 0.006-scale space shuttle vehicle in a 3.5-foot hypersonic wind tunnel are presented. The purpose of these tests was to parametrically investigate the ascent heating of the integrated vehicle. Configurations tested were complete for integrated vehicle, orbiter alone, external tank alone, and SRB alone. All configurations were tested with and without transition grit. Testing was conducted at a Mach number of 5.3, and at Reynolds numbers of 2 and 5 million per foot. The angle of attack range varied from 0 to minus 5 degress, execpt for SRB alone, which was tested from minus 5 to 90 degrees. Heat transfer data were obtained from 223 iron-constantan thermocouples attached to thin-skin stainless steel inserts.

  12. Aeroheating model advancements featuring electroless metallic plating

    NASA Technical Reports Server (NTRS)

    Stalmach, C. J., Jr.; Goodrich, W. D.


    Discussed are advancements in wind tunnel model construction methods and hypersonic test data demonstrating the methods. The general objective was to develop model fabrication methods for improved heat transfer measuring capability at less model cost. A plated slab model approach was evaluated with cast models containing constantan wires that formed single-wire-to-plate surface thermocouple junctions with a seamless skin of electroless nickel alloy. The surface of a space shuttle orbiter model was selectively plated with scaled tiles to simulate, with high fidelity, the probable misalignments of the heatshield tiles on a flight vehicle. Initial, Mach 8 heating results indicated a minor effect of tile misalignment roughness on boundary layer transition, implying a possible relaxation of heatshield manufacturing tolerances. Some loss of the plated tiles was experienced when the model was tested at high heating rates.

  13. BOREAS TE-6 1994 Soil and Air Temperatures in the NSA

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Norman, John; Wilson, Tim


    The BOREAS TE-6 team collected several data sets to examine the influence of vegetation, climate, and their interactions on the major carbon fluxes for boreal forest species. This data set contains measurements of the air temperature at a single height and soil temperature at several depths in the NSA from 25-May to 08-Oct- 1994. Chromel-Constantan thermocouple wires run by a miniprogrammable data logger (Model 21X, Campbell Scientific, Inc., Logan, UT) provided direct measurements of temperature. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

  14. Statistical Analysis of a Round-Robin Measurement Survey of Two Candidate Materials for a Seebeck Coefficient Standard Reference Material.


    Lu, Z Q J; Lowhorn, N D; Wong-Ng, W; Zhang, W; Thomas, E L; Otani, M; Green, M L; Tran, T N; Caylor, C; Dilley, N R; Downey, A; Edwards, B; Elsner, N; Ghamaty, S; Hogan, T; Jie, Q; Li, Q; Martin, J; Nolas, G; Obara, H; Sharp, J; Venkatasubramanian, R; Willigan, R; Yang, J; Tritt, T


    In an effort to develop a Standard Reference Material (SRM™) for Seebeck coefficient, we have conducted a round-robin measurement survey of two candidate materials-undoped Bi2Te3 and Constantan (55 % Cu and 45 % Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active thermoelectric research using a number of different commercial and custom-built measurement systems and techniques. In this paper we report the detailed statistical analyses on the interlaboratory measurement results and the statistical methodology for analysis of irregularly sampled measurement curves in the interlaboratory study setting. Based on these results, we have selected Bi2Te3 as the prototype standard material. Once available, this SRM will be useful for future interlaboratory data comparison and instrument calibrations.

  15. Temperature field in rubber vibration isolators

    NASA Astrophysics Data System (ADS)

    Abdulhadi, M. Issa


    The temperature field inside a vibrating rubber solid cylinder is investigated. The rubber cylinder, a specimen of a vibration isolator rubber (Neoprene GR), is subjected to a repeatedly cyclic compressive force by means of an electrodynamic shaker. In the experimental investigation the temperatures at 16 different locations inside the cylinder have been measured by means of copper-constantan thermocouples. After the estimation of the heat generated per unit volume per unit time with the help of the estimated damping and stiffness coefficients of rubber, one can attempt the solution of the heat conduction equation describing the temperature field inside the rubber specimen. The values of the temperature found from the analytical investigation compare fairly well with the experimental measurements.

  16. Evaluation of measurement errors of temperature and relative humidity from HOBO data logger under different conditions of exposure to solar radiation.


    da Cunha, Antonio Ribeiro


    This study aimed to assess measurements of temperature and relative humidity obtained with HOBO a data logger, under various conditions of exposure to solar radiation, comparing them with those obtained through the use of a temperature/relative humidity probe and a copper-constantan thermocouple psychrometer, which are considered the standards for obtaining such measurements. Data were collected over a 6-day period (from 25 March to 1 April, 2010), during which the equipment was monitored continuously and simultaneously. We employed the following combinations of equipment and conditions: a HOBO data logger in full sunlight; a HOBO data logger shielded within a white plastic cup with windows for air circulation; a HOBO data logger shielded within a gill-type shelter (multi-plate prototype plastic); a copper-constantan thermocouple psychrometer exposed to natural ventilation and protected from sunlight; and a temperature/relative humidity probe under a commercial, multi-plate radiation shield. Comparisons between the measurements obtained with the various devices were made on the basis of statistical indicators: linear regression, with coefficient of determination; index of agreement; maximum absolute error; and mean absolute error. The prototype multi-plate shelter (gill-type) used in order to protect the HOBO data logger was found to provide the best protection against the effects of solar radiation on measurements of temperature and relative humidity. The precision and accuracy of a device that measures temperature and relative humidity depend on an efficient shelter that minimizes the interference caused by solar radiation, thereby avoiding erroneous analysis of the data obtained.

  17. Characterizing the effective density and primary particle diameter of airborne nanoparticles produced by spark discharge using mobility and mass measurements (tandem DMA/APM)

    NASA Astrophysics Data System (ADS)

    Charvet, Augustin; Bau, Sébastien; Paez Coy, Natalia Estefania; Bémer, Denis; Thomas, Dominique


    Nanoparticles are increasingly used in a wide variety of industries. As yet, their health effects are incompletely characterized. Effective density is among the key characteristics of airborne nanoparticles due to its role in particle deposition in the human respiratory tract and in the conversion of number distributions to mass distributions. Because it cannot be measured directly, different methods have been developed to accede to this parameter. The approach chosen in this study is based on the tandem measurement of airborne nanoparticles electrical mobility and mass (tandem differential mobility analyzer/aerosol particle mass analyzer), which major advantage lies in the absence of hypothesis contrary to the tandem differential mobility analyzer/electrical low pressure impactor (DMA/ELPI). The methodology was first applied to spherical model particles to validate the associated data treatment and protocol. In particular, the influence of APM rotational velocity and airflow rate were investigated with regards to the separation of multiply charged particles and electrometer signal. It emerged from experimental data that a compromise between separation efficiency and detection limit shall be found, depending on the nanoparticles to characterize. Accounting for their wide use in different domains, airborne nanoparticles of constantan®, copper, graphite, iron, silver and titanium, produced by spark discharge appear to be representative of ultrafine particles stemming from different industrial processes. In addition to their effective density, the mass-mobility exponents and primary particle diameters were determined for these particles, and found to agree well with published data.

  18. A Surface-Enhanced Raman Scattering Sensor Integrated with Battery-Controlled Fluidic Device for Capture and Detection of Trace Small Molecules

    PubMed Central

    Zhou, Qitao; Meng, Guowen; Zheng, Peng; Cushing, Scott; Wu, Nianqiang; Huang, Qing; Zhu, Chuhong; Zhang, Zhuo; Wang, Zhiwei


    For surface-enhanced Raman scattering (SERS) sensors, one of the important issues is the development of substrates not only with high SERS-activity but also with strong ability to capture analytes. However, it is difficult to achieve the two goals simultaneously especially when detecting small molecules. Herein a compact battery-controlled nanostructure-assembled SERS system has been demonstrated for capture and detection of trace small molecule pollutants in water. In this SERS fluidic system, an electrical heating constantan wire covered with the vertically aligned ZnO nanotapers decorated with Ag-nanoparticles is inserted into a glass capillary. A mixture of thermo-responsive microgels, Au-nanorods colloids and analyte solution is then filled into the remnant space of the capillary. When the system is heated by switching on the battery, the thermo-responsive microgels shrink, which immobilizes the analyte and drives the Au-nanorod close to each other and close to the Ag-ZnO nanotapers. This process has also created high-density “hot spots” due to multi-type plasmonic couplings in three-dimensional space, amplifying the SERS signal. This integrated device has been successfully used to measure methyl parathion in lake water, showing a great potential in detection of aquatic pollutants. PMID:26238799

  19. Apparatus for the Measurement of Thermoelectric Power

    NASA Astrophysics Data System (ADS)

    Hishida, Shoji; Ho, Pei-Chun

    The Seebeck Effect refers to the electric potential that is established in a material under an imposed temperature gradient. This effect provides a useful tool for characterizing the thermal and electric transport behavior of materials. A measurement probe is under development in order to measure the Seebeck Coefficient (Thermoelectric Power) of a sample over the temperature range from 10 - 300 K in a cryocooler system. The sample is mounted between two platforms: one that is thermally connected with the measurement probe and another that is thermally isolated, referred to as the cold and hot platforms respectively. A 2k Ω resistance heater on the hot platform is used to establish a temperature gradient across the sample and between the two platforms. A Cernox resistance thermometer measures the temperature of the cold platform, and a Type T differential thermocouple, composed of copper-constantan-copper wires, is used to measure the temperature difference. The probe will be calibrated using the known thermopowers of Nickel, Platinum, and Chromel samples. The performance results of this design will be presented. Research at CSU-Fresno is supported by NSF DMR-1506677. Shoji Hishida is also supported by the Undergraduate Research Grant at CSU Fresno.

  20. Experimental verification of bioheat transfer theories: measurement of temperature profiles around large artificial vessels in perfused tissue.


    Crezee, J; Lagendijk, J J


    The verification of thermal models for use in hyperthermia treatment planning is essential. We investigated the heat transfer between a single vessel and the surrounding vascularised tissue, comparing the conventional bioheat transfer theory and the recently developed keff model using analytical and numerical methods. A plastic tube inserted into the tissue of an isolated perfused organ served as an artificial vessel. This enabled us to vary the blood flow in the vessel and in the tissue independently. The organ used was a bovine kidney, turned into a perfused tissue phantom using an alcohol fixation technique. The temperature profile within the tissue was mapped with constantan-manganin thermocouple wire sensors with a total diameter of 50 microns. The temperature profile relative to the temperature difference between the vessel and organ was measured; increased perfusion caused a reduction of the vessel wall temperature but did not affect the width of the profile. Studying the transient tissue temperature after a step-wise change of the blood temperature in the vessel revealed a faster diffusion of heat at higher perfusion rates. These facts are in accordance with the keff model, but not with the conventional heat-sink theory.

  1. Finite element analysis of (SA) mechanoreceptors in tactile sensing application

    NASA Astrophysics Data System (ADS)

    N, Syamimi; Yahud, S.


    This paper addresses the structural design of a fingertip model in order to analyse the sensory function of slow adapting (SA) mechanoreceptors by using the finite element analysis (FEA) method. A biologically inspired tactile sensor was designed to mimic a similar response of the human mechanoreceptors in the human glabrous skin. The simulation work was done by using COMSOL Multiphysics. The artificial skin was modelled as a solid square block of silicone elastomer with a semi cylinder protrusion on top. It was modelled as a nearly incompressible and linear hyperelastic material defined by Neo Hookean constitutive law. The sensing element on the other hand was modelled by using constantan alloy mimicking the SA1 receptor. Boundary loads of 1 N/m² to 4 N/m² with the increment of 1 N/m² were applied to the top surface of the protrusion in z and x-direction for normal and shear stress, respectively. The epidermal model base was constrained to maintain the same boundary conditions throughout all simulations. The changes of length experienced by the sensing element were calculated. The simulations result in terms of strain was identified. The simulated result was plotted in terms of sensing element strain against the boundary load and the graph should produce a linear response.

  2. Thermocyclic stability of candidate Seebeck coefficient standard reference materials at high temperature

    NASA Astrophysics Data System (ADS)

    Martin, Joshua; Wong-Ng, Winnie; Caillat, Thierry; Yonenaga, I.; Green, Martin L.


    The Seebeck coefficient is the most widely measured property specific to thermoelectric materials. There is currently no consensus on measurement protocols, and researchers employ a variety of techniques to measure the Seebeck coefficient. The implementation of standardized measurement protocols and the use of reliable Seebeck Coefficient Standard Reference Materials (SRMs®) will allow the accurate interlaboratory comparison and validation of materials data, thereby accelerating the development and commercialization of more efficient thermoelectric materials and devices. To enable members of the thermoelectric materials community the means to calibrate Seebeck coefficient measurement equipment, NIST certified SRM® 3451 "Low Temperature Seebeck Coefficient Standard (10 K to 390 K)". Due to different practical requirements in instrumentation, sample contact methodology, and thermal stability, a complementary SRM® is required for the high temperature regime (300 K to 900 K). The principal requirement of a SRM® for the Seebeck coefficient at high temperature is thermocyclic stability. We therefore characterized the thermocyclic behavior of the Seebeck coefficient for a series of candidate materials: constantan, p-type single crystal SiGe, and p-type polycrystalline SiGe, by measuring the temperature dependence of the Seebeck coefficient as a function of 10 sequential thermal cycles, between 300 K and 900 K. We employed multiple regression analysis to interpolate and analyze the thermocyclic variability in the measurement curves.

  3. Studies on microwave and blood-brain barrier interaction

    SciTech Connect

    Lin, J.C.; Lin, M.F.


    This investigation was aimed at correlating changes of blood-brain-barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats anesthetized by sodium pentobarbital. Through use of thermographic methods and a direct-contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein and in the left external carotid artery. Evans blue and sodium fluorescein in isotonic saline were used as visual indicators of barrier permeation. Exposure to pulsed 2,450-MHz radiation for 20 min at average power densities of 0.5, 1, 5, 20, 145 or 1,000 mW/cm2, which resulted in average specific absorption rates (SARs) of 0.04, 0.08, 0.4, 1.6, 11.5 or 80.0 mW/g in the brain, did not produce staining, except in the pineal body, the pituitary gland, and the choroid plexus - regions that normally are highly permeable. Except for these regions, staining was also absent in the brains of sham-exposed animals. The rectal temperature, as monitored by a copper-constantan thermocouple, showed a maximum increase of less than 0.75 degrees C from a mean pre-exposure temperature of 36.6 degrees C. The highest brain temperature recorded in a similar group of animals using a thickfilm carbon thermistor was less than 41.0 degrees C.

  4. A new method for simultaneous measurement of Seebeck coefficient and resistivity

    NASA Astrophysics Data System (ADS)

    He, Xu; Yang, Junyou; Jiang, Qinghui; Luo, Yubo; Zhang, Dan; Zhou, Zhiwei; Ren, Yangyang; Li, Xin; Xin, Jiwu; Hou, Jingdi


    A new method has been proposed and verified to measure the Seebeck coefficient and electrical resistivity of a sample in the paper. Different from the conventional method for Seebeck coefficient and resistivity measurement, the new method adopts a four-point configuration to measure both the Seebeck coefficient and resistivity. It can well identify the inhomogeneity of the sample by simply comparing the four Seebeck coefficients of different probe combinations, and it is more accurate and appropriate to take the average value of the four Seebeck coefficients as the measured result of the Seebeck coefficient of the sample than that measured by the two-point method. Furthermore, the four-point configuration makes it also very convenient to measure the resistivity by using the Van der Pauw method. The validity of this method has been verified with both the constantan alloy and p-type Bi2Te3 semiconductor samples, and the measurement results are in good agreement with those obtained by commercial available equipment.

  5. A new method for simultaneous measurement of Seebeck coefficient and resistivity.


    He, Xu; Yang, Junyou; Jiang, Qinghui; Luo, Yubo; Zhang, Dan; Zhou, Zhiwei; Ren, Yangyang; Li, Xin; Xin, Jiwu; Hou, Jingdi


    A new method has been proposed and verified to measure the Seebeck coefficient and electrical resistivity of a sample in the paper. Different from the conventional method for Seebeck coefficient and resistivity measurement, the new method adopts a four-point configuration to measure both the Seebeck coefficient and resistivity. It can well identify the inhomogeneity of the sample by simply comparing the four Seebeck coefficients of different probe combinations, and it is more accurate and appropriate to take the average value of the four Seebeck coefficients as the measured result of the Seebeck coefficient of the sample than that measured by the two-point method. Furthermore, the four-point configuration makes it also very convenient to measure the resistivity by using the Van der Pauw method. The validity of this method has been verified with both the constantan alloy and p-type Bi2Te3 semiconductor samples, and the measurement results are in good agreement with those obtained by commercial available equipment.

  6. Development of MEMS-based thermal flow sensors for high sensitivity and wide range of flow rate

    NASA Astrophysics Data System (ADS)

    Kang, Woong; Choi, Hae Man; Choi, Yong Moon


    We have proposed and demonstrated a novel design of MEMS-based thermal mass flow sensor for high sensitivity and wide flow range. Thermal mass flow sensors are able to measure small amount of gas flow such as process control gas via heat transfer phenomena between heater and thermopiles. To understand characteristics of the correlation between sensing performance and geometry of sensor components like heater and thermopile, various designed models were fabricated by using MEMS technology considering manufacturing efficiency. A evanohm R alloy heater and chromel-constantan thermopiles were formed on a Si3N4/SiO2/Si3N4 sandwich type membrane for thermal performance enhancement. Characteristics tests between flow rate, heat power and sensitivity for fabricated models were conducted in low pressure gas flow standard system of KRISS (Korea Research Institute of Standard and Science) with MFC (Mass Flow Controller). Finally, the optimum geometry based on the non-uniform distribution of heater and thermopiles was determined according to characteristics comparison of designed and fabricated models. The developed thermal mass flow sensor can be adopted for low range flow rate (0 - 200 sccm) and also high one (up to 10 SLM) with high sensitivity. This work was supported by the Korea Research Institute of Standards and Science under the project `Establishment of National Physical Measurement Standards and Improvements of Calibration/Measurement Capability,' grant 12011002.

  7. Evaluation of the effect of V2O5 on the electrical and thermoelectric properties of poly(vinyl alcohol)/graphene nanoplatelets nanocomposite

    NASA Astrophysics Data System (ADS)

    Morad, M.; Fadlallah, M. M.; Hassan, M. A.; Sheha, E.


    The aim of this contribution is to introduce high performance materials for thermoelectric devices. A nanopolymer composite of PVAGNP ((polyvinyl alcohol ((PVA)0.6/graphene nanoplatelets (GNP)0.4))1-x(V2O5)x where x = 0, 2.5, 5, 7.5 and 10 wt% has been prepared using a solution cast technique. The influence of V2O5 additives on the morphology, structure, thermal and electrical properties of PVA has been examined by FTIR, XRD, TGA, DC and IV techniques. The disassociation of V2O5 to (V4+) and (V5+) in the composites acts as a co-bridge which can facilitate the translational electronic motion, which enhances the charge carrier mobility and the electrical conductivity. A prototype cell was constructed using (PVAGNP)1-x(GNP)x nanocomposites with constantan wire. The addition of V2O5 improves the thermoelectric properties of the (PVA)0.6(GNP)0.4 nanocomposite, where the Seebeck coefficient is increased from 23.1 to 45.8 μV K-1 from 0 to 10 wt% V2O5, respectively. The power factor is increased from 1.17 × 10-2 to 36.30 × 10-2 μWm-1 K-2 from 0 to 10 wt% V2O5, respectively, and the ZT is increased from 4.47 × 10-9 to 1.46 × 10-7.

  8. Simulation, design and fabrication of a planar micro thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Pelegrini, S.; Adami, A.; Collini, C.; Conci, P.; Lorenzelli, L.; Pasa, A. A.


    This study describes the design, simulation, and micro fabrication of a micro thermoelectric generator (μTEG) based on planar technology using constantan (CuNi) and copper (Cu) thermocouples deposited electrochemically (ECD) on silicon substrate. The present thin film technology can be manufactured into large area and also on flexible substrate with low cost of production and can be used to exploit waste heat from equipments or hot surfaces in general. In the current implementation, the silicon structure has been designed and optimized with analytical models and FE simulations in order to exploit the different thermal conductivity of silicon and air gaps to produce the maximum temperature difference on a planar surface. The results showed that a temperature difference of 10K across the structure creates a temperature difference of 5.3K on the thermocouples, thus providing an efficiency of thermal distribution up to 55%, depending on the heat convection at the surface. Efficiency of module has been experimentally tested under different working condition, showing the dependence of module output on the external heat exchange (natural and forced convection). Maximum generated potential at 6m/s airflow is 5.7V/m2 K and thermoelectric efficiency is 1.9μW K-2 m-2.

  9. Dual mode fracture of composite laminates penetrated by spherical projectiles

    NASA Astrophysics Data System (ADS)

    Czarnecki, G. J.

    The basic for delamination initiation and propagation within an impacted laminate was studied, with an explanation provided for the fracture mode transformation along the projectile's path. Post-impact observations of graphite/epoxy (AS4/3501-6) laminates penetrated by steel spheres (0.5-inch diameter) reveal a fracture mode, similar to shear plugging adjacent to the impacted surface. This fracture mode is contrasted with that of delamination adjacent to the rear surface. The sudden transition from shear plugging to delamination is believed to occur when the projectile interacts with the returning impact-generated tensile wave. To demonstrate the transition, results are presented from ballistically impacted laminates containing a series of imbedded carbon stress and constantan strain gages. Results are based on impact velocities of 1300, 1850, and 2380 f/s. Transverse stress waves are shown capable of creating delamination until attenuated by a local zone of compressed material associated with the on-coming projectile. Based on experimental results, the location of the fracture mode transition plane is predicted both graphically and through a simple equation of motion.

  10. Performance of a small, low-lift regenerator-based thermoacoustic refrigerator

    NASA Astrophysics Data System (ADS)

    Poese, Matthew E.; Garrett, Steven L.


    A regenerator-based thermoacoustic refrigerator [Swift, Gardner, and Backhaus, ''Acoustic recovery of lost power in pulse tube refrigerators,'' J. Acoust. Soc. Am. 105(2), 711 (1999)] has been constructed. It is capable of moving about 5 W across a 40degC temperature span. The machine operates with air at atmospheric pressure and is driven by an off-the-shelf electro-dynamic loudspeaker capable of producing peak-to-mean pressure ratios up to 12%. The thermal core of this research device contains an exhaust-side shell and tube heat exchanger (with water as the secondary heat transfer fluid), a regenerator made of 88 annular stainless-steel screens, and a constantan wire electrical heater that applies a measurable heat load to the cold side of the regenerator. An annular latex diaphragm is placed over the cold side of the regenerator to stop time-averaged mass flow through the regenerator and insulate the cold side [Gedeon, ''DC Gas Flows in Stirling and Pulse Tube Cryocoolers,'' in Cryocoolers 9, edited by R. G. Ross (Plenum, New York, 1997)]. Detailed measurements of heat load, temperature span, and exhaust heat flux will be presented and compared to DeltaE. [Work supported by ONR.

  11. Practical system for the direct measurement of magneto-caloric effect by micro-thermocouples.


    Kamarád, J; Kaštil, J; Arnold, Z


    A system for direct measurements of the magneto-caloric effect (MCE) exploits a rapid transport of a sample into or from magnetic field in permanent Halbach-type (1 T) or superconducting (4.7 T) magnets. Time dependence of induced changes of the sample temperature, ΔT(t), is detected directly by the differential Cu-Constantan-Cu micro-thermocouples with time steps of 300 ms. A sample placed inside an evacuated simple LN(2) cryostat is either totally isolated (adiabatic conditions) or partly connected with the copper sample holder (non-adiabatic conditions). The last arrangement (a model of the Brayton cycle) is used to simulate an application of MCE in refrigeration techniques. The relations describing ΔT(t) that allow an analysis of MCE of the studied materials are based on the general cooling law. The effect of the first-order magnetic transition on MCE of selected sample is also demonstrated by non-standard ΔT(t) curves measured in the last mentioned experimental arrangements.

  12. Heat transfer characteristics of igniter output plumes

    NASA Astrophysics Data System (ADS)

    Evans, N. A.; Durand, N. A.

    Seven types of pyrotechnic igniters were each mounted at one end of a closed cylindrical bore hole representative of the center hole in a thermal battery. Measurements of local bore wall temperature, T(sub w), using commercially available, fast response (10 microsec) sheathed chromel-constantan thermocouples allowed calculation of local heat transfer rates, q, and wall heat flows, Q. The principal charge constituents of all these igniters were titanium and potassium perchlorate, while three types also contained barium styphnate as an ignition sensitizer. Igniter closure disc materials included glass-ceramic, glass, metal (plain, scored, with and without capture cone), and kapton/RTV. All igniters produced the lowest values of T(sub w) and q at the beginning of the bore, and, except for the igniter with the kapton/RTV closure disc, these quantities increased with distance along the bore. For igniters containing only titanium/potassium perchlorate, the rates of increase of Q along the bore length, compared with those for T(sub w) and q, were generally lower and more variable. The inclusion of barium styphnate produced rates of change in Q that were essentially constant to the end of the bore. The highest overall average wall temperatures were achieved by two igniter types with metal closure discs and no capture cone. No clear correlation was established between peak bore pressure and maximum wall temperature.

  13. Sliding bubbles on a hot horizontal wire in a subcooled bath

    NASA Astrophysics Data System (ADS)

    Duchesne, Alexis; Dubois, Charles; Caps, Hervé


    When a wire is heated up to the boiling point in a liquid bath some bubbles will nucleate on the wire surface. Traditional nucleate boiling theory predicts that bubbles generate from active nucleate site, grow up and depart from the heating surface due to buoyancy and inertia. However, an alternative scenario is presented in the literature for a subcooled bath: bubbles slide along the horizontal wire before departing. New experiments were performed by using a constantan wire and different liquids, varying the injected power. Silicone oil, water and even liquid nitrogen were tested in order to vary wetting conditions, liquid viscosities and surface tensions. We explored the influence of the wire diameter and of the subcooled bath temperature. We observed, of course, sliding motion, but also a wide range of behaviors from bubbles clustering to film boiling. We noticed that bubbles could change moving sense, especially when encountering with another bubble. The bubble speed is carefully measured and can reach more than 100 mm/s for a millimetric bubble. We investigated the dependence of the speed on the different parameters and found that this speed is, for a given configuration, quite independent of the injected power. We understand these phenomena in terms of Marangoni effects. This project has been financially supported by ARC SuperCool contract of the University of Liège.

  14. Aeroheating Measurement of Apollo Shaped Capsule with Boundary Layer Trip in the Free-piston Shock Tunnel HIEST

    NASA Technical Reports Server (NTRS)

    Hideyuki, TANNO; Tomoyuki, KOMURO; Kazuo, SATO; Katsuhiro, ITOH; Lillard, Randolph P.; Olejniczak, Joseph


    An aeroheating measurement test campaign of an Apollo capsule model with laminar and turbulent boundary layer was performed in the free-piston shock tunnel HIEST at JAXA Kakuda Space Center. A 250mm-diameter 6.4%-scaled Apollo CM capsule model made of SUS-304 stainless steel was applied in this study. To measure heat flux distribution, the model was equipped with 88 miniature co-axial Chromel-Constantan thermocouples on the heat shield surface of the model. In order to promote boundary layer transition, a boundary layer trip insert with 13 "pizza-box" isolated roughness elements, which have 1.27mm square, were placed at 17mm below of the model geometric center. Three boundary layer trip inserts with roughness height of k=0.3mm, 0.6mm and 0.8mm were used to identify the appropriate height to induce transition. Heat flux records with or without roughness elements were obtained for model angles of attack 28º under stagnation enthalpy between H(sub 0)=3.5MJ/kg to 21MJ/kg and stagnation pressure between P(sub 0)=14MPa to 60MPa. Under the condition above, Reynolds number based on the model diameter was varied from 0.2 to 1.3 million. With roughness elements, boundary layer became fully turbulent less than H(sub 0)=9MJ/kg condition. However, boundary layer was still laminar over H(sub 0)=13MJ/kg condition even with the highest roughness elements. An additional experiment was also performed to correct unexpected heat flux augmentation observed over H(sub 0)=9MJ/kg condition.

  15. Brain temperature and pH measured by (1)H chemical shift imaging of a thulium agent.


    Coman, Daniel; Trubel, Hubert K; Rycyna, Robert E; Hyder, Fahmeed


    Temperature and pH are two of the most important physiological parameters and are believed to be tightly regulated because they are intricately related to energy metabolism in living organisms. Temperature and/or pH data in mammalian brain are scarce, however, mainly because of lack of precise and non-invasive methods. At 11.7 T, we demonstrate that a thulium-based macrocyclic complex infused through the bloodstream can be used to obtain temperature and pH maps of rat brain in vivo by (1)H chemical shift imaging (CSI) of the sensor itself in conjunction with a multi-parametric model that depends on several proton resonances of the sensor. Accuracies of temperature and pH determination with the thulium sensor - which has a predominantly extracellular presence - depend on stable signals during the course of the CSI experiment as well as redundancy for temperature and pH sensitivities contained within the observed signals. The thulium-based method compared well with other methods for temperature ((1)H MRS of N-acetylaspartate and water; copper-constantan thermocouple wire) and pH ((31)P MRS of inorganic phosphate and phosphocreatine) assessment, as established by in vitro and in vivo studies. In vitro studies in phantoms with two compartments of different pH value observed under different ambient temperature conditions generated precise temperature and pH distribution maps. In vivo studies in alpha-chloralose-anesthetized and renal-ligated rats revealed temperature (33-34 degrees C) and pH (7.3-7.4) distributions in the cerebral cortex that are in agreement with observations by other methods. These results show that the thulium sensor can be used to measure temperature and pH distributions in rat brain in vivo simultaneously and accurately using Biosensor Imaging of Redundant Deviation in Shifts (BIRDS).

  16. Pulvinus activity, leaf movement and leaf water-use efficiency of bush bean ( Phaseplus vulgaris L.) in a hot environment

    NASA Astrophysics Data System (ADS)

    Raeini-Sarjaz, Mahmoud; Chalavi, Vida


    Pulvinus activity of Phaseolus species in response to environmental stimuli plays an essential role in heliotropic leaf movement. The aims of this study were to monitor the continuous daily pulvinus movement and pulvinus temperature, and to evaluate the effects of leaf movements, on a hot day, on instantaneous leaf water-use efficiency (WUEi), leaf gas exchange, and leaf temperature. Potted plants of Phaseolus vulgaris L. var. Provider were grown in Chicot sandy loam soil under well-watered conditions in a greenhouse. When the second trifoliate leaf was completely extended, one plant was selected to measure pulvinus movement using a beta-ray gauging (BRG) meter with a point source of thallium-204 (204Tl). Leaf gas exchange measurements took place on similar leaflets of three plants at an air temperature interval of 33-42°C by a steady-state LI-6200 photosynthesis system. A copper-constantan thermocouple was used to monitor pulvinus temperature. Pulvinus bending followed the daily diurnal rhythm. Significant correlations were found between the leaf-incident angle and the stomatal conductance ( R 2 = 0.54; P < 0.01), and photosynthesis rate ( R 2 = 0.84; P < 0.01). With a reduction in leaf-incidence angle and increase in air temperature, WUEi was reduced. During the measurements, leaf temperature remained below air temperature and was a significant function of air temperature ( r = 0.92; P < 0.01). In conclusion, pulvinus bending followed both light intensity and air temperature and influenced leaf gas exchange.

  17. Unileg Thermoelectric Generator Design for Oxide Thermoelectrics and Generalization of the Unileg Design Using an Idealized Metal

    NASA Astrophysics Data System (ADS)

    Wijesekara, Waruna; Rosendahl, Lasse; Brown, David R.; Snyder, G. Jeffrey


    The unileg thermoelectric generator (U-TEG) is an increasingly popular concept in the design of thermoelectric generators (TEGs). In this study, an oxide U-TEG design for high-temperature applications is introduced. For the unicouple TEG design, Ca3Co4O9 and Al-doped ZnO are used as the p- and n-leg thermoelectric materials, respectively. For the U-TEG design, constantan and Ca3Co4O9 are employed as conductor and semiconductor, respectively. The reduced current approach (RCA) technique is used to design the unicouple TEG and U-TEG in order to obtain the optimal area ratio. When both the unicouple TEG and U-TEG were subjected to a heat flux of 20 W/cm2, the volumetric power density was 0.18 W/cm3 and 0.44 W/cm3, respectively. Thermal shorting between the hot and cold sides of the generator through the highly thermally conducting conductor, which is one of the major drawbacks of the U-TEG, is overcome by using the optimal area ratio for conductor and semiconductor given by the RCA. The results are further confirmed by finite-element analysis using COMSOL Multiphysics software. Furthermore, the U-TEG design is generalized by using an idealized metal with zero Seebeck coefficient. Even though the idealized metal has no impact on the power output of the U-TEG and all the power in the system is generated by the semiconductor, the U-TEG design succeeded in producing a higher volumetric power density than the unicouple TEG design.

  18. Uncertainty analysis of thermocouple measurements used in normal and abnormal thermal environment experiments at Sandia's Radiant Heat Facility and Lurance Canyon Burn Site.

    SciTech Connect

    Nakos, James Thomas


    It would not be possible to confidently qualify weapon systems performance or validate computer codes without knowing the uncertainty of the experimental data used. This report provides uncertainty estimates associated with thermocouple data for temperature measurements from two of Sandia's large-scale thermal facilities. These two facilities (the Radiant Heat Facility (RHF) and the Lurance Canyon Burn Site (LCBS)) routinely gather data from normal and abnormal thermal environment experiments. They are managed by Fire Science & Technology Department 09132. Uncertainty analyses were performed for several thermocouple (TC) data acquisition systems (DASs) used at the RHF and LCBS. These analyses apply to Type K, chromel-alumel thermocouples of various types: fiberglass sheathed TC wire, mineral-insulated, metal-sheathed (MIMS) TC assemblies, and are easily extended to other TC materials (e.g., copper-constantan). Several DASs were analyzed: (1) A Hewlett-Packard (HP) 3852A system, and (2) several National Instrument (NI) systems. The uncertainty analyses were performed on the entire system from the TC to the DAS output file. Uncertainty sources include TC mounting errors, ANSI standard calibration uncertainty for Type K TC wire, potential errors due to temperature gradients inside connectors, extension wire uncertainty, DAS hardware uncertainties including noise, common mode rejection ratio, digital voltmeter accuracy, mV to temperature conversion, analog to digital conversion, and other possible sources. Typical results for 'normal' environments (e.g., maximum of 300-400 K) showed the total uncertainty to be about {+-}1% of the reading in absolute temperature. In high temperature or high heat flux ('abnormal') thermal environments, total uncertainties range up to {+-}2-3% of the reading (maximum of 1300 K). The higher uncertainties in abnormal thermal environments are caused by increased errors due to the effects of imperfect TC attachment to the test item. 'Best

  19. Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test

    SciTech Connect

    Forbes, J.W.; Tarver, C.M.; Chidester, S.K.; Garcia, F.; Greenwood, D.W.; Garza, R.


    The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. This test has a hemispherical projectile traveling at tens of m/s impacting a metal cased explosive target. To assist in the understanding of this safety test, two-dimensional shock wave gauge techniques were used to measure the pressures of a few kilobars and times of reactions less than a millisecond. This work is in accord with a long-term goal to develop two-dimensional shock diagnostic techniques that are more than just time of arrival indicators. Experiments were performed where explosives were impacted at levels below shock initiation levels but caused low level reactions. Carbon foil and carbon resistor pressure gauges were used to measure pressures and time of events. The carbon resistor gauges indicate a late time low level reaction at 350 {micro}s after impact of the hemispherical projectile creating 0.5-6 kb peak shocks at the center of PBX 9501 (HMX/Estane/BDNPA-F; 95/2.5/2.5 wt %) explosive discs. The Steven test calculations are based on an ignition and growth criteria and found that the low level reaction occurs at 335 {micro}s, which is in good agreement with the experimental data. Some additional experiments simulating the Steven impact test were done on a gas gun with carbon foil and constantan strain gauges in a PMMA target. Hydrodynamic calculations can be used to evaluate the gauge performance in these experiments and check the lateral strain measurements.

  20. High-Speed Automated Tester for Vacuum Chamber Feedthrough Connectors and Cables

    NASA Technical Reports Server (NTRS)

    Swope, Robert H.; Powers, Edward I. (Technical Monitor)


    The Goddard Space Flight Center's thermal vacuum laboratory has developed a high-speed automated system for testing the integrity of 37-pin MIL-C-5015 cylindrical electrical feedthrough connectors used on penetration plates of thermal vacuum chambers. The system consists of a desktop PC driving a data acquisition front end. The latter measures the resistance through each pin of the connector and the resistance from each pin to all other pins and the connector shell. In addition to identifying unacceptable feedthroughs, the system is also used for testing cables. In the special case of Type T thermocouples (used almost exclusively at the lab), the difference in resistance between the copper and constantan wires provides positive proof of accidentally reversed connector wiring. Data acquisition time to completely test a cable or feedthrough connector is less than thirty seconds. The system provides a hardcopy printout of the resistance readings. Connectors or cables with fewer wires are tested using simple adapter cables. Initial tests indicate that the performance of a given feedthrough connector can be predicted on the basis of measured resistance readings, reducing ongoing cost of connector replacement. The opportunity to positively certify the integrity of cables, cable connectors and feedthroughs before the start of a thermal vacuum test minimizes the likelihood of a circuit problem that would require returning the chamber to ambient conditions for repair. This system has two principal advantages for the Goddard thermal vacuum laboratory. Its only significant cost was the labor to fabricate the test cable and shorting cable -- about 40 man-hours total. The system was built around a computer and data acquisition unit that were already on hand. The second advantage is that it very quickly tests both of the parameters that are essential.

  1. Performance study of a laboratory model shallow solar pond with and without single transparent glass cover for solar thermal energy conversion applications.


    Ganesh, S; Arumugam, S


    The thermal performance of a shallow solar pond with and without the single transparent glass cover has been investigated experimentally. This experiment has been performed during the summer season of 2014 under the operational condition for five different storage volumes of water upto a maximum of 10liter. The pond performance is investigated in terms of the rate of energy collected and its collection efficiency. A Low Density Polyethylene (LDPE) black sheet liner of 200μm thickness was laid on all the interior sides of the pond for solar energy absorption. A clear transparent PVC plastic sheet of 150μm thickness was laid over the water surface as evaporation suppressing membrane. Calibrated Copper constantan thermocouples were used to measure the temperatures of the system. A highest temperature of 81.5°C has been achieved for the stored volume of 2liter of water, when the pond was used with a single transparent glass cover of 5mm thickness. When the shallow solar pond was used without the transparent glass cover the system attained a maximum temperature of 62°C for the same stored volume of 2liter. A comparison between the two conditions of with and without the transparent glass cover, on the thermal performance of the SSP has been reported. A shallow solar pond system of the present type could be used us a source of warm water, of desired temperature, below 10°C which are required for the domestic and industrial utilities. The global warming is increased day by day; inorder to reduce global warming a typical method of small scale shallow solar pond has been used to absorb the radiation from the sun to convert it to useful heat energy by the source of water. The SSP is an eco friendly way to generate energy without polluting our environment and in an environment safety manner. Based on environmental safety this study has experimentally investigated the thermal performance of the shallow solar pond.

  2. Numerical heat transfer during partially-confined, confined, and free liquid jet impingement with rotation and chemical mechanical planarization process modeling

    NASA Astrophysics Data System (ADS)

    Lallave Cortes, Jorge C.

    This work presents the use of numerical modeling for the analysis of transient and steady state liquid jet impingement for cooling application of electronics, and energy dissipation during a CMP process under the influence of a series of parameters that controls the transport phenomena mechanism. Seven thorough studies were done to explore how the flow structure and conjugated heat transfer in both the solid and fluid regions was affected by adding a secondary rotational flow during the jet impingement process. Axis-symmetrical numerical models of round jets with a spinning or static nozzle were developed using the following configurations: confined, partially-confined, and free liquid jet impingement on a rotating or stationary uniformly heated disk of finite thickness and radius. Calculations were done for various materials, namely copper, silver, Constantan, and silicon with a solid to fluid thermal conductivity ratio covering a range of 36.91.2222, at different laminar Reynolds numbers ranging from 220 to 2,000, under a broad rotational rate range of 0 to 1,000 RPM (Ekman number=infinity--3.31x10--5), nozzle-to-plate spacing (beta=, dimensionless disk thicknesses (b/dn=, confinement ratio (rp/rd=, and Prandtl number ( using NH3, H2O, FC.77 and MIL.7808 as working fluids. An engineering correlation relating the average Nusselt number with the above parameters was developed for the prediction of system performance. The simulation results compared reasonably well with previous experimental studies. The second major contribution of this research was the development of a three dimensional CMP model that shows the temperature distributions profile as an index of energy dissipation at the wafer and pad surfaces, and slurry interface. A finite element analysis was done with FIDAP 8.7.4 package under the influence of physical parameters, such as slurry flow rates ( cc/s), polishing pressures ( kPa), pad

  3. An Innovative Modeling and Measurement Approach to Improve Rice Water Use Efficiency in California

    NASA Astrophysics Data System (ADS)

    Montazar, A.; Little, C.; Rejmanek, H.; Tindula, G.; Snyder, R. L.


    California is amongst the top rice producing states in the USA, and more than 95 percent of California's rice is grown in the Sacramento Valley. Based on older literature, the rice water requirement (ETc), ranges between 914 and 1,100 mm. In this study, the actual rice water requirement was measured using the residual of the energy balance method over three paddy rice fields during 2011-2013 seasons in the Sacramento Valley. Net radiation and ground heat flux density were measured, and both eddy covariance (EC) and the surface renewal (SR) technique were employed to determine the sensible heat flux density. The surface renewal method uses high frequency temperature measurements from fine wire thermocouples above the canopy. Mean amplitude and duration of the ramps over half hour periods were determined using a structure function and the characteristics are employed to estimate the direction and magnitude of sensible heat flux using the ratio of the amplitude to the ramp duration as the change in temperature per unit time and the volumetric heat capacity of the air to estimate the magnitude of the heat flux. In the study, 76.2 mm diameter chromel-constantan thermocouples were used to measure high frequency temperature at 10 Hz. The results indicate that there is considerable variability in rice water use both spatially and temporally. The average three-year measured ET of the experimental fields located in Butte County was 734 and 725 mm; and in Colusa County was 771 mm. A typical crop coefficient (Kc) curve was derived from the measured ETc and reference ET (ETo) data. Spatial estimates of monthly climate data from the Sacramento Valley were used to calculate monthly mean ETo, and smooth curve fits of the monthly data gave estimates of typical daily ETo. The daily ETc was calculated as the product of ETo and Kc, and seasonal ETc was calculated by summing the daily ETc values. The results reveal that the seasonal rice ETc was less than earlier estimates. Surface

  4. Real-time RNN-based acoustic thermometry with feedback control

    NASA Astrophysics Data System (ADS)

    Hsu, Stephen J.; Nam, Joana H.; Fan, Liexiang; Brunke, Shelby S.; Sekins, K. Michael


    A major obstacle to the widespread adoption of HIFU therapy is the development of a suitable method of monitoring the a blation therapy in real-time. While MR-thermometry has emerged as a promising method for HIFU therapy monitoring, acoustic guidance has continuously been sought for reasons of cost and practicality. We have previously demonstrated the potential of acoustic thermometry, by using a recurrent neural network (RNN) to estimate changes in tissue temperature during HIFU ablation therapies. A limitation of this method is that an excessive therapeutic dose can cause multiple, non-linear changes within the ultrasound data, resulting in unreliable temperature estimates from the RNN. Accordingly, we propose a revised method of dosing wherein closed loop feedback is used to provide a controlled and specific dose; not only to ensure an efficacious lesion, but also to preserve the integrity of the ultrasound image, thereby producing accurate temperature estimates from the RNN. This investigation of controlling the thermal dose using feedback was performed on ex vivo bovine liver. The acoustic parameters used as inputs to the RNN were: changes in integrated backscatter intensity, thermal strain, and decorrelation. The therapeutic dose was delivered using a 1.1 MHz, 2D-array HIFU transducer transmitting at regular intervals during a 40-second dose. Interleaved between these regular HIFU dose intervals, volumetric ultrasound images were acquired on a Siemens ACUSON SC2000, with a 4Zlc probe. Feedback was introduced to the system by varying the HIFU duty cycle, in order to minimize the difference between a desired temperature curve (assigned a priori) and the estimated focal temperature values. Two methods were used for obtaining the focal temperature: the first was direct measurement using a 75-micron copper-constantan thermocouple embedded within the liver sample, and the second was temperature estimation as calculated from the RNN-based output temperatures

  5. U.S. Space Radioisotope Power Systems and Applications: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Cataldo, Robert L.; Bennett, Gary L.


    -1906) and R. J. Strut. Almost 100 years ago, in 1913, English physicist H. G. J. Moseley (1887-1915) constructed the first nuclear battery using a vacuum flask and 20 mCi of radium (Corliss and Harvey, 1964, Proceedings of the Royal Society, 1913). After World War II, serious interest in radioisotope power systems in the U.S. was sparked by studies of space satellites such as North American Aviation s 1947 report on nuclear space power and the RAND Corporation s 1949 report on radioisotope power. (Greenfield, 1947, Gendler and Kock, 1949). Radioisotopes were also considered in early studies of nuclear-powered aircraft (Corliss and Harvey, 1964). In 1951, the U.S. Atomic Energy Commission (AEC) signed several contracts to study a 1-kWe space power plant using reactors or radioisotopes. Several of these studies, which were completed in 1952, recommended the use of RPS. (Corliss and Harvey, 1964). In 1954, the RAND Corporation issued the summary report of the Project Feedback military satellite study in which radioisotope power was considered (Lipp and Salter, 1954, RAND). Paralleling these studies, in 1954, K. C. Jordan and J. H. Birden of the AEC s Mound Laboratory conceived and built the first RTG using chromel-constantan thermocouples and a polonium-210 (210Po or Po-210) radioisotope heat source (see Figure 2). While the power produced (1.8 mWe) was low by today s standards, this first RTG showed the feasibility of RPS. A second thermal battery was built with more Po-210, producing 9.4 mWe. Jordan and Birden concluded that the Po-210 thermal battery would have about ten times the energy of ordinary dry cells of the same mass (Jordan and Birden, 1954). The heat source consisted of a 1-cm-diameter sphere of 57 Ci (1.8 Wt) of Po-210 inside a capsule of nickel-coated cold-rolled steel all inside a container of Lucite. The thermocouples were silver-soldered chromel-constantan. The thermal battery produced 1.8 mWe.

  6. Assessment of groundwater availability in the Northern Atlantic Coastal Plain aquifer system From Long Island, New York, to North Carolina

    USGS Publications Warehouse

    Masterson, John P.; Pope, Jason P.; Fienen, Michael N.; Monti, Jr., Jack; Nardi, Mark R.; Finkelstein, Jason S.


    , and the boundary between freshwater and saltwater as it approaches equilibrium. The largest change in water budget components is the reduction in the amount of water released from storage.Across the entire NACP aquifer system, the reduction of storage release from 7 to 4 percent of the total water budget change is accounted for by reductions in groundwater discharge to streams and coastal waters. Locally, a similar response is calculated for each of the geographic areas except for Virginia where the amount of water released from storage accounts for about 25 percent of the total change in water budget. This finding suggests that the groundwater flow system in Virginia is not approaching equilibrium under the current [2013] stresses and, therefore, water levels will continue to decrease even if the pumping remains constant.An analysis of the change in water levels in the Potomac-Patapsco aquifer as pumping is continued 30 years into the future reveals that the largest decreases in water levels throughout the NACP aquifer system will occur in the southern Virginia and northeastern North Carolina parts of the study area. It is these areas that also see the greatest potential for increased lateral movement of saline groundwater in the deep, confined portion of the groundwater flow system in response to a continuation of the current [2013] pumping rates.The potential effects of long-term climate change and variability on the hydrologic system and availability of water resources in the NACP aquifer system continue to be of serious societal concern. These concerns include the effects of changes in aquifer recharge and in sea-level rise on the groundwater flow system. An assessment of the potential effects of a prolonged drought during current [2013] pumping conditions indicated that the reductions in recharge associated with droughts, including additional irrigation withdrawals required to meet increased crop water demand, have the greatest effects on water levels and