WorldWideScience

Sample records for thermal modulation measurements

  1. Thermal performance measurements on ATLAS-SCT KB forward modules

    CERN Document Server

    Donegà, M; D'Onofrio, M; Ferrère, D; Hirt, C; Ikegami, Y; Kohriki, T; Kondo, T; Lindsay, S; Mangin-Brinet, M; Niinikoski, T O; Pernegger, H; Perrin, E; Taylor, G; Terada, S; Unno, Y; Wallny, R; Weber, M

    2003-01-01

    The thermal design of the KB module is presented. A Finite Elements Analysis (FEA) has been used to finalize the module design. The thermal performance of an outer irradiated KB module has been measured at different cooling conditions. The thermal runaway of the module has been measured. The FEA model has been compared with the measurements and has been used to predict the thermal performance in a realistic SCT scenario.

  2. Measurements of thermal parameters of solar modules

    International Nuclear Information System (INIS)

    Górecki, K; Krac, E

    2016-01-01

    In the paper the methods of measuring thermal parameters of photovoltaic panels - transient thermal impedance and the absorption factor of light-radiation are presented. The manner of realising these methods is described and the results of measurements of the considered thermal parameters of selected photovoltaic panels are presented. The influence of such selected factors as a type of the investigated panel and its mounting manner on transient thermal impedance of the considered panels is also discussed. (paper)

  3. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    Science.gov (United States)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  4. Application of double modulation for measurement of the thermal expansion coefficient of liquid metals

    International Nuclear Information System (INIS)

    Blagonravov, L A; Karchevskiy, O O; Ivannikov, P V; Soboleva, A V

    2008-01-01

    The first results of the thermal expansion coefficient measurement obtained for liquid conductors using a new modulation method are presented. The method is based on a superposition of two periodical influences on a liquid metal. The thermal expansion coefficient α P is determined by means of measuring the amplitudes of oscillations of electric current power w ∼ and pressure p ∼ . In the present work the K-Na alloy of the eutectic composition was used as a sample. Distinction of the experimental data obtained by authors from the literature data is 30 to 40%. Such a difference is in the range of error of determination of α P from the density data of K-Na alloy. The method allows direct determination of the thermal expansion coefficient of liquid conductors in absolute units

  5. In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Hacke, Peter; Sera, Dezso

    We analyze the degradation of multi-crystalline silicon photovoltaic modules undergoing simultaneous thermal, mechanical, and humidity-freeze stress testing to develop a dark environmental chamber in-situ measurement procedure for determining module power loss. We analyze dark I-V curves measured...

  6. Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

    Science.gov (United States)

    Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

    2009-05-01

    The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

  7. Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

    International Nuclear Information System (INIS)

    Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

    2009-01-01

    The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

  8. Temperature Modulated Nanomechanical Thermal Analysis

    DEFF Research Database (Denmark)

    Alves, Gustavo Marcati A.; Bose-Goswami, Sanjukta; Mansano, Ronaldo D.

    2018-01-01

    The response of microcantilever deflection to complex heating profiles was used to study thermal events like glass transition and enthalpy relaxation on nanograms of the biopolymer Poly(lactic-co-glycolic acid) (PLGA). The use of two heating rates enables the separation of effects on the deflection...... response that depends on previous thermal history (non-reversing signal) and effects that depends only on the heating rate variation (reversing signal). As these effects may appear superposed in the total response, temperature modulation can increase the measurement sensitivity to some thermal events when...

  9. Modulated Current Drive Measurements

    International Nuclear Information System (INIS)

    Petty, C.C.; Lohr, J.; Luce, T.C.; Prater, R.; Cox, W.A.; Forest, C.B.; Jayakumar, R.J.; Makowski, M.A.

    2005-01-01

    A new measurement approach is presented which directly determines the noninductive current profile from the periodic response of the motional Stark effect (MSE) signals to the slow modulation of the external current drive source. A Fourier transform of the poloidal magnetic flux diffusion equation is used to analyze the MSE data. An example of this measurement technique is shown using modulated electron cyclotron current drive (ECCD) discharges from the DIII-D tokamak

  10. Three frequency modulated combination thermal neutron lifetime log and porosity

    International Nuclear Information System (INIS)

    Paap, H.J.; Arnold, D.M.; Smith, M.P.

    1976-01-01

    Methods are disclosed for measuring simultaneously the thermal neutron lifetime of the borehole fluid and earth formations in the vicinity of a well borehole, together with the formation porosity. A harmonically intensity modulated source of fast neutrons is used to irradiate the earth formations with fast neutrons at three different modulation frequencies. Intensity modulated clouds of thermal neutrons at each of the three modulation frequencies are detected by dual spaced detectors and the relative phase shift of the thermal neutrons with respect to the fast neutrons is determined at each of the three modulation frequencies at each detector. These measurements are then combined to determine simultaneously the thermal neutron decay time of the borehole fluid, the thermal neutron decay time of surrounding earth formation media and the porosity of the formation media

  11. Reduced thermal conductivity of isotopically modulated silicon multilayer structures

    DEFF Research Database (Denmark)

    Bracht, H.; Wehmeier, N.; Eon, S.

    2012-01-01

    We report measurements of the thermal conductivity of isotopically modulated silicon that consists of alternating layers of highly enriched silicon-28 and silicon-29. A reduced thermal conductivity of the isotopically modulated silicon compared to natural silicon was measured by means of time......-resolved x-ray scattering. Comparison of the experimental results to numerical solutions of the corresponding heat diffusion equations reveals a factor of three lower thermal conductivity of the isotope structure compared to natural Si. Our results demonstrate that the thermal conductivity of silicon can...

  12. Thermal Properties Measurement Report

    Energy Technology Data Exchange (ETDEWEB)

    Carmack, Jon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Braase, Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Papesch, Cynthia [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hurley, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tonks, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gofryk, Krzysztof [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fielding, Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Knight, Collin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Meyer, Mitch [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The Thermal Properties Measurement Report summarizes the research, development, installation, and initial use of significant experimental thermal property characterization capabilities at the INL in FY 2015. These new capabilities were used to characterize a U3Si2 (candidate Accident Tolerant) fuel sample fabricated at the INL. The ability to perform measurements at various length scales is important and provides additional data that is not currently in the literature. However, the real value of the data will be in accomplishing a phenomenological understanding of the thermal conductivity in fuels and the ties to predictive modeling. Thus, the MARMOT advanced modeling and simulation capability was utilized to illustrate how the microstructural data can be modeled and compared with bulk characterization data. A scientific method was established for thermal property measurement capability on irradiated nuclear fuel samples, which will be installed in the Irradiated Material Characterization Laboratory (IMCL).

  13. Measurement of thermal conductance

    International Nuclear Information System (INIS)

    Kuchnir, M.

    1977-01-01

    The 6-m long, 45-kG, warm-iron superconducting magnets envisioned for the Energy Doubler stage of the Fermilab accelerator require stiff supports with minimized thermal conductances in order to keep the refrigeration power reasonable. The large number of supports involved in the system required a careful study of their heat conduction from the room temperature wall to the intercepting refrigeration at 20 0 K and to the liquid helium. For this purpose the thermal conductance of this support was measured by comparing it with the thermal conductance of a copper strap of known geometry. An association of steady-state thermal analysis and experimental thermal conductivity techniques forms the basis of this method. An important advantage is the automatic simulation of the 20 0 K refrigeration intercept by the copper strap, which simplifies the apparatus considerably. This relative resistance technique, which uses electrical analogy as a guideline, is applicable with no restrictions for materials with temperature-independent thermal conductivity. For other materials the results obtained are functions of the specific temperature interval involved in the measurements. A comprehensive review of the literature on thermal conductivity indicates that this approach has not been used before. A demonstration of its self-consistency is stressed here rather than results obtained for different supports

  14. Thermal Testing Measurements Report

    Energy Technology Data Exchange (ETDEWEB)

    R. Wagner

    2002-09-26

    The purpose of the Thermal Testing Measurements Report (Scientific Analysis Report) is to document, in one report, the comprehensive set of measurements taken within the Yucca Mountain Project Thermal Testing Program since its inception in 1996. Currently, the testing performed and measurements collected are either scattered in many level 3 and level 4 milestone reports or, in the case of the ongoing Drift Scale Test, mostly documented in eight informal progress reports. Documentation in existing reports is uneven in level of detail and quality. Furthermore, while all the data collected within the Yucca Mountain Site Characterization Project (YMP) Thermal Testing Program have been submitted periodically to the Technical Data Management System (TDMS), the data structure--several incremental submittals, and documentation formats--are such that the data are often not user-friendly except to those who acquired and processed the data. The documentation in this report is intended to make data collected within the YMP Thermal Testing Program readily usable to end users, such as those representing the Performance Assessment Project, Repository Design Project, and Engineered Systems Sub-Project. Since either detailed level 3 and level 4 reports exist or the measurements are straightforward, only brief discussions are provided for each data set. These brief discussions for different data sets are intended to impart a clear sense of applicability of data, so that they will be used properly within the context of measurement uncertainty. This approach also keeps this report to a manageable size, an important consideration because the report encompasses nearly all measurements for three long-term thermal tests. As appropriate, thermal testing data currently residing in the TDMS have been reorganized and reformatted from cumbersome, user-unfriendly Input-Data Tracking Numbers (DTNs) into a new set of Output-DTNs. These Output-DTNs provide a readily usable data structure

  15. Thermal power measurement apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Thermal power measurements are important in nuclear power plants, fossil-fuel plants and other closed loop systems such as heat exchangers and chemical reactors. The main object of this invention is to determine the enthalpy of a fluid using only acoustically determined sound speed and correlating the speed with enthalpy. An enthalpy change is measured between two points in the fluid flow: the apparatus is described in detail. (U.K.)

  16. Thermal performance of the Atlas SCT forward modules

    CERN Document Server

    Clark, A; Nasteva, I; Snow, S W; Wallny, R; Wilmut, I

    2003-01-01

    We describe the thermal design of the Atlas SCT forward modules and their cooling blocks. We report on the performance of the $C_3 F_8$ evaporative cooling system and the blocks alone, then on the performance of an irradiated inner module mounted on two alternative prototype cooling blocks (baseline and PEEK split). Runs are presented at different cooling conditions, representative of those expected to be used in the final experiment. We have also measured thermal runaway, with the module mounted on the PEEK split block and cooled with liquid cooling.

  17. Nonreciprocal Thermal Material by Spatiotemporal Modulation

    Science.gov (United States)

    Torrent, Daniel; Poncelet, Olivier; Batsale, Jean-Chirstophe

    2018-03-01

    The thermal properties of a material with a spatiotemporal modulation, in the form of a traveling wave, in both the thermal conductivity and the specific heat capacity are studied. It is found that these materials behave as materials with an internal convectionlike term that provides them with nonreciprocal properties, in the sense that the heat flux has different properties when it propagates in the same direction or in the opposite one to the modulation of the parameters. An effective medium description is presented which accurately describes the modulated material, and numerical simulations support this description and verify the nonreciprocal properties of the material. It is found that these materials are promising candidates for the design of thermal diodes and other advanced devices for the control of the heat flow at all scales.

  18. Thermal Module Tests with Irradiated 070 Detectors.

    CERN Document Server

    HOWCROFT, C L F

    1998-01-01

    Four n-in-n detectors were irradiated at KEK to a fluence of 3*1014 protons cm-2. These were used to construct a thermal barrel module to 070 drawings with an A3-90 baseboard at the Rutherford Appleton Laboratory. Thermal testes were conducted on the module, examining the runaway point and the temperatures across the silicon. The results obtained were used to calculate the runaway point under ATLAS conditions. It was concluded that this module meets the specifications in the Technical Design Report, of 160 mW mm-2@ 0°C for runaway and less than 5°C across the silicon. The module was also compared to a Finite Element Analysis, and showed a good agreement.

  19. Modulation characteristics of graphene-based thermal emitters

    Science.gov (United States)

    Mahlmeister, Nathan Howard; Lawton, Lorreta Maria; Luxmoore, Isaac John; Nash, Geoffrey Richard

    2016-01-01

    We have investigated the modulation characteristics of the emission from a graphene-based thermal emitter both experimentally and through simulations using finite element method modelling. Measurements were performed on devices containing square multilayer graphene emitting areas, with the devices driven by a pulsed DC drive current over a range of frequencies. Simulations show that the dominant heat path is from the emitter to the underlying substrate, and that the thermal resistance between the graphene and the substrate determines the modulation characteristics. This is confirmed by measurements made on devices in which the emitting area is encapsulated by hexagonal boron nitride.

  20. Thermal effects in microfluidics with thermal conductivity spatially modulated

    Science.gov (United States)

    Vargas Toro, Agustín.

    2014-05-01

    A heat transfer model on a microfluidic is resolved analytically. The model describes a fluid at rest between two parallel plates where each plate is maintained at a differentially specified temperature and the thermal conductivity of the microfluidic is spatially modulated. The heat transfer model in such micro-hydrostatic configuration is analytically resolved using the technique of the Laplace transform applying the Bromwich Integral and the Residue theorem. The temperature outline in the microfluidic is presented as an infinite series of Bessel functions. It is shown that the result for the thermal conductivity spatially modulated has as a particular case the solution when the thermal conductivity is spatially constant. All computations were performed using the computer algebra software Maple. It is claimed that the analytical obtained results are important for the design of nanoscale devices with applications in biotechnology. Furthermore, it is suggested some future research lines such as the study of the heat transfer model in a microfluidic resting between coaxial cylinders with radially modulated thermal conductivity in order to achieve future developments in this area.

  1. Outdoor thermal and electrical characterisation of photovoltaic modules and systems

    OpenAIRE

    Herteleer, Bert

    2016-01-01

    Current and future investors in photovoltaic systems are interested in how well the system performs, and how predictable this is over the expected lifetime. To do so, models have been developed and measurements of photovoltaic systems have been done. This dissertation presents the outdoor measurement set-up that has been developed for thermal and electrical characterisation of photovoltaic modules and systems, aimed at measuring transient effects and changes. The main design decisions and ...

  2. Thermal diffusivity effect in opto-thermal skin measurements

    International Nuclear Information System (INIS)

    Xiao, P; Imhof, R E; Cui, Y; Ciortea, L I; Berg, E P

    2010-01-01

    We present our latest study on the thermal diffusivity effect in opto-thermal skin measurements. We discuss how thermal diffusivity affects the shape of opto-thermal signal, and how to measure thermal diffusivity in opto-thermal measurements of arbitrary sample surfaces. We also present a mathematical model for a thermally gradient material, and its corresponding opto-thermal signal. Finally, we show some of our latest experimental results of this thermal diffusivity effect study.

  3. Thermal management, systems and modules; Thermomanagement, Systeme und Module

    Energy Technology Data Exchange (ETDEWEB)

    Flik, M. [Behr GmbH und Co., Stuttgart (Germany)

    1999-11-01

    Up till now the individual systems for engine temperature control and air conditioning of the vehicle cabin have to a large extent been viewed independently of one another. With the progress of electronic control systems, however, Behr has adopted an integrative approach to managing all heat and substance flows outside of the engine. This perspective, which is known as thermal management, has significantly boosted the rate of innovation. In a short period of time, new and optimized modules and systems have allowed considerable improvements to be made in relation to passenger comfort and safety, the integration of subsystems and modules into the vehicle and environmental compatibility. This innovation drive, which also extends to the design of major modules, will continue to gain impetus in the future. (orig.) [German] Bisher wurden die verschiedenen Systeme zur Temperierung des Motors und zur Klimatisierung der Fahrzeugkabine weitgehend unabhaengig voneinander betrachtet. Mit dem Vordringen der elektronischen Regelung hat bei Behr jedoch eine gesamtheitliche Betrachtung aller Waerme- und Stoffstroeme ausserhalb des Motors eingesetzt. Diese Sichtweise, Thermomanagement genannt, hat eine erhebliche Innovationsdynamik ermoeglicht. Mit neuen und optimierten Modulen und Systemen konnten in kurzer Zeit betraechtliche Verbesserungen erzielt werden - bei Komfort und Sicherheit der Fahrzeuginsassen, bei der Integration der Subsysteme und Module ins Fahrzeug sowie bei seiner oekologischen Vertraeglichkeit. Diese Innovationsdynamik, die auch die Bildung von Grossmodulen einschliesst, wird in Zukunft noch zunehmen. (orig.)

  4. Thermally modulated biomolecule transport through nanoconfined channels.

    Science.gov (United States)

    Liu, Lei; Zhu, Lizhong

    2015-01-01

    In this work, a nanofluidic device containing both a feed cell and a permeation cell linked by nanopore arrays has been fabricated, which is employed to investigate thermally controlled biomolecular transporting properties through confined nanochannels. The ionic currents modulated by the translocations of goat antibody to human immunoglobulin G (IgG) or bovine serum albumin (BSA) are recorded and analyzed. The results suggest that the modulation effect decreases with the electrolyte concentration increasing, while the effects generated by IgG translocation are more significant than that generated by BSA translocation. More importantly, there is a maximum decreasing value in each modulated current curve with biomolecule concentration increasing for thermally induced intermolecular collision. Furthermore, the turning point for the maximum shifts to lower biomolecule concentrations with the system temperature rising (from 4°C to 45°C), and it is mainly determined by the temperature in the feed cell if the temperature difference exists in the two separated cells. These findings are expected to be valuable for the future design of novel sensing device based on nanopore and/or nanopore arrays.

  5. Measuring thermal neutron characteristics

    International Nuclear Information System (INIS)

    Johnstone, C.W.; Jacobson, L.A.

    1983-01-01

    A method for providing a background-compensated measurement of the level of inducted radiation within an earth formation is claimed. The formation is irradiated with a discrete burst of neutrons and the level of radiation in the formation measured. The level of background radiation is then measured. An average level of both measurements is obtained

  6. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  7. A Lumped Thermal Model Including Thermal Coupling and Thermal Boundary Conditions for High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2018-01-01

    Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three......-dimensional thermal models based on Finite Element Method (FEM) need massive computations, which make the long-term thermal dynamics difficult to calculate. In this paper, a new lumped three-dimensional thermal model is proposed, which can be easily characterized from FEM simulations and can acquire the critical...

  8. Mirage effect from thermally modulated transparent carbon nanotube sheets.

    Science.gov (United States)

    Aliev, Ali E; Gartstein, Yuri N; Baughman, Ray H

    2011-10-28

    The single-beam mirage effect, also known as photothermal deflection, is studied using a free-standing, highly aligned carbon nanotube aerogel sheet as the heat source. The extremely low thermal capacitance and high heat transfer ability of these transparent forest-drawn carbon nanotube sheets enables high frequency modulation of sheet temperature over an enormous temperature range, thereby providing a sharp, rapidly changing gradient of refractive index in the surrounding liquid or gas. The advantages of temperature modulation using carbon nanotube sheets are multiple: in inert gases the temperature can reach > 2500 K; the obtained frequency range for photothermal modulation is ~100 kHz in gases and over 100 Hz in high refractive index liquids; and the heat source is transparent for optical and acoustical waves. Unlike for conventional heat sources for photothermal deflection, the intensity and phase of the thermally modulated beam component linearly depends upon the beam-to-sheet separation over a wide range of distances. This aspect enables convenient measurements of accurate values for thermal diffusivity and the temperature dependence of refractive index for both liquids and gases. The remarkable performance of nanotube sheets suggests possible applications as photo-deflectors and for switchable invisibility cloaks, and provides useful insights into their use as thermoacoustic projectors and sonar. Visibility cloaking is demonstrated in a liquid.

  9. High-precision thermal and electrical characterization of thermoelectric modules

    Science.gov (United States)

    Kolodner, Paul

    2014-05-01

    This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.

  10. Periodic and stochastic thermal modulation of protein folding kinetics.

    Science.gov (United States)

    Platkov, Max; Gruebele, Martin

    2014-07-21

    Chemical reactions are usually observed either by relaxation of a bulk sample after applying a sudden external perturbation, or by intrinsic fluctuations of a few molecules. Here we show that the two ideas can be combined to measure protein folding kinetics, either by periodic thermal modulation, or by creating artificial thermal noise that greatly exceeds natural thermal fluctuations. We study the folding reaction of the enzyme phosphoglycerate kinase driven by periodic temperature waveforms. As the temperature waveform unfolds and refolds the protein, its fluorescence color changes due to FRET (Förster resonant Energy Transfer) of two donor/acceptor fluorophores labeling the protein. We adapt a simple model of periodically driven kinetics that nicely fits the data at all temperatures and driving frequencies: The phase shifts of the periodic donor and acceptor fluorescence signals as a function of driving frequency reveal reaction rates. We also drive the reaction with stochastic temperature waveforms that produce thermal fluctuations much greater than natural fluctuations in the bulk. Such artificial thermal noise allows the recovery of weak underlying signals due to protein folding kinetics. This opens up the possibility for future detection of a stochastic resonance for protein folding subject to noise with controllable amplitude.

  11. Characterization of a photovoltaic-thermal module for Fresnel linear concentrator

    International Nuclear Information System (INIS)

    Chemisana, D.; Ibanez, M.; Rosell, J.I.

    2011-01-01

    Highlights: → A combined domed Fresnel lens - CPC PVT system is designed and characterized. → Electrical and thermal experiments have been performed. → CFD analysis has been used to determine thermal characteristic dimensionless numbers. - Abstract: An advanced solar unit is designed to match the needs of building integration and concentrating photovoltaic/thermal generation. The unit proposed accurately combines three elements: a domed linear Fresnel lens as primary concentrator, a compound parabolic reflector as secondary concentrator and a photovoltaic-thermal module. In this work the photovoltaic-thermal generator is built, analysed and characterized. Models for the electrical and thermal behaviour of the module are developed and validated experimentally. Applying a thermal resistances approach the results from both models are combined. Finally, efficiency electrical and thermal curves are derived from theoretical analysis showing good agreement with experimental measurements.

  12. Pattern-free thermal modulator via thermal radiation between Van der Waals materials

    Science.gov (United States)

    Liu, Xianglei; Shen, Jiadong; Xuan, Yimin

    2017-10-01

    Modulating heat flux provides a platform for a plethora of emerging devices such as thermal diodes, thermal transistors, and thermal memories. Here, a pattern-free noncontact thermal modulator is proposed based on the mechanical rotation between two Van der Waals films with optical axes parallel to the surfaces. A modulation contrast can reach a value higher than 5 for hexagonal Boron Nitride (hBN) films separated by a nanoscale gap distance. The dominant radiative heat exchange comes from the excitation of both Type I and Type II hyperbolic surface phonon polaritons (HSPhPs) at the vacuum-hBN interface for different orientations, while the large modulation contrast is mainly attributed to the mismatching Type I HSPhPs induced by rotation. This work opens the possibility to design cheap thermal modulators without relying on nanofabrication techniques, and paves the way to apply natural Van der Waals materials in manipulating heat currents in an active way.

  13. A review of passive thermal management of LED module

    NARCIS (Netherlands)

    Ye, H.; Sau, K.; Zeijl, H. van; Gielen, A.W.J.; Zhang, G.

    2011-01-01

    Recently, the high-brightness LEDs have begun to be designed for illumination application. The increased electrical currents used to drive LEDs lead to thermal issues. Thermal management for LED module is a key design parameter as high operation temperature directly affects their maximum light

  14. Thermal Diffusivity Measurements in Edible Oils using Transient Thermal Lens

    Science.gov (United States)

    Valdez, R. Carbajal.; Pérez, J. L. Jiménez.; Cruz-Orea, A.; Martín-Martínez, E. San.

    2006-11-01

    Time resolved thermal lens (TL) spectrometry is applied to the study of the thermal diffusivity of edible oils such as olive, and refined and thermally treated avocado oils. A two laser mismatched-mode experimental configuration was used, with a He Ne laser as a probe beam and an Ar+ laser as the excitation one. The characteristic time constant of the transient thermal lens was obtained by fitting the experimental data to the theoretical expression for a transient thermal lens. The results showed that virgin olive oil has a higher thermal diffusivity than for refined and thermally treated avocado oils. This measured thermal property may contribute to a better understanding of the quality of edible oils, which is very important in the food industry. The thermal diffusivity results for virgin olive oil, obtained from this technique, agree with those reported in the literature.

  15. Mechanical and Thermal Characterisation of a TT Half-Module Prototype

    CERN Document Server

    Lehner, F; Pangilinan, M; Siegler, M

    2005-01-01

    This note describes the mechanical effects of thermal cycles on a TT half-module, to demonstrate that the detectors can withstand the expected thermal gradients without damage. The stress transferred by the carbon fiber rails and the ceramic to the silicon sensors was investigated, and the deformation that occurred during these tests was measured by strain gauges that were attached to sensors on a test half-module. In addition, heat transfer through the carbon fiber rails was studied. Furthermore, we present a comparison of different materials proposed to build the carbon fiber rails of the modules.

  16. Thermal management of solid state lighting module

    NARCIS (Netherlands)

    Ye, H.

    2014-01-01

    Solid-State Lighting (SSL), powered by Light-Emitting Diodes (LEDs), is an energy-efficient technology for lighting systems. In contrast to incandescent lights which obtain high efficiency at high temperatures, the highest efficiency of LEDs is reached at low temperatures. The thermal management in

  17. Continuous measurements on a modulating system

    International Nuclear Information System (INIS)

    Gariod, R.; Tournier, E.

    1963-01-01

    We have developed a number of measuring and testing instruments for which interesting characteristics have been obtained through modulation. In this paper, we would like to emphasize the interest of using the synchronous demodulation when a previous modulation has been used in the device. We give the fundamentals of some embodiments applied to nuclear and physical parameters measurements. (authors) [fr

  18. Laboratory measurements of rock thermal properties

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Balling, N.; Nielsen, S.B.

    The thermal properties of rocks are key elements in understanding and modelling the temperature field of the subsurface. Thermal conductivity and thermal diffusivity can be measured in the laboratory if rock samples can be provided. We have introduced improvements to the divided bar and needle...... probe methods to be able to measure both thermal conductivity and thermal diffusivity. The improvements we implement include, for both methods, a combination of fast numerical finite element forward modelling and a Markov Chain Monte Carlo inversion scheme for estimating rock thermal parameters...

  19. Thermal analysis of compositionally modulated Fe/Y films

    International Nuclear Information System (INIS)

    Kajiura, M.; Morishita, T.; Togami, Y.; Tsushima, K.

    1987-01-01

    Structures of compositionally modulated Fe/Y films were studied by thermal analysis. The exothermic peak found in the DSC curve of (Fe 12 A/Y 12 A) most probably corresponds to crystallization of an amorphous material. SEM analysis suggested that the composition of crystallized (Fe 12 A/Y 12 A) was YFe2. It is concluded that a compositionally modulated (Fe 12 A/Y 12 A) is amorphous in structure as well as in magnetic properties

  20. Thermal and Performance Analysis of a Photovoltaic Module with an Integrated Energy Storage System

    Directory of Open Access Journals (Sweden)

    Manel Hammami

    2017-10-01

    Full Text Available This paper is proposing and analyzing an electric energy storage system fully integrated with a photovoltaic PV module, composed by a set of lithium-iron-phosphate (LiFePO4 flat batteries, which constitutes a generation-storage PV unit. The batteries were surface-mounted on the back side of the PV module, distant from the PV backsheet, without exceeding the PV frame size. An additional low-emissivity sheet was introduced to shield the batteries from the backsheet thermal irradiance. The challenge addressed in this paper is to evaluate the PV cell temperature increase, due to the reduced thermal exchanges on the back of the module, and to estimate the temperature of the batteries, verifying their thermal constraints. Two one-dimensional (1D thermal models, numerically implemented by using the thermal library of Simulink-Matlab accounting for all the heat exchanges, are here proposed: one related to the original PV module, the other related to the portion of the area of the PV module in correspondence of the proposed energy-storage system. Convective and radiative coefficients were then calculated in relation to different configurations and ambient conditions. The model validation has been carried out considering the PV module to be at the nominal operating cell temperature (NOCT, and by specific experimental measurements with a thermographic camera. Finally, appropriate models were used to evaluate the increasing cell batteries temperature in different environmental conditions.

  1. Bone assessment via thermal photoacoustic measurements

    Science.gov (United States)

    Feng, Ting; Kozloff, Kenneth M.; Hsiao, Yi-Sing; Tian, Chao; Perosky, Joseph; Du, Sidan; Yuan, Jie; Deng, Cheri X.; Wang, Xueding

    2015-03-01

    The feasibility of an innovative biomedical diagnostic technique, thermal photoacoustic (TPA) measurement, for nonionizing and non-invasive assessment of bone health is investigated. Unlike conventional photoacoustic PA methods which are mostly focused on the measurement of absolute signal intensity, TPA targets the change in PA signal intensity as a function of the sample temperature, i.e. the temperature dependent Grueneisen parameter which is closely relevant to the chemical and molecular properties in the sample. Based on the differentiation measurement, the results from TPA technique is less susceptible to the variations associated with sample and system, and could be quantified with improved accurately. Due to the fact that the PA signal intensity from organic components such as blood changes faster than that from non-organic mineral under the same modulation of temperature, TPA measurement is able to objectively evaluate bone mineral density (BMD) and its loss as a result of osteoporosis. In an experiment on well established rat models of bone loss and preservation, PA measurements of rat tibia bones were conducted over a temperature range from 370 C to 440 C. The slope of PA signal intensity verses temperature was quantified for each specimen. The comparison among three groups of specimens with different BMD shows that bones with lower BMD have higher slopes, demonstrating the potential of the proposed TPA technique in future clinical management of osteoporosis.

  2. New simultaneous thermogravimetry and modulated molecular beam mass spectrometry apparatus for quantitative thermal decomposition studies

    International Nuclear Information System (INIS)

    Behrens, R. Jr.

    1987-01-01

    A new type of instrument has been designed and constructed to measure quantitatively the gas phase species evolving during thermal decompositions. These measurements can be used for understanding the kinetics of thermal decomposition, determining the heats of formation and vaporization of high-temperature materials, and analyzing sample contaminants. The new design allows measurements to be made on the same time scale as the rates of the reactions being studied, provides a universal detection technique to study a wide range of compounds, gives quantitative measurements of decomposition products, and minimizes interference from the instrument on the measurements. The instrument design is based on a unique combination of thermogravimetric analysis (TGA), differential thermal analysis (DTA), and modulated beam mass spectroscopy (MBMS) which are brought together into a symbiotic relationship through the use of differentially pumped vacuum systems, modulated molecular beam techniques, and computer control and data-acquisition systems. A data analysis technique that calculates partial pressures in the reaction cell from the simultaneous microbalance force measurements and the modulated mass spectrometry measurements has been developed. This eliminates the need to know the ionization cross section, the ion dissociation channels, the quadrupole transmission, and the ion detector sensitivity for each thermal decomposition product prior to quantifying the mass spectral data. The operation of the instrument and the data analysis technique are illustrated with the thermal decomposition of contaminants from a precipitated palladium powder

  3. Photovoltaic thermal module concepts and their performance analysis: A review

    International Nuclear Information System (INIS)

    Hasan, M. Arif; Sumathy, K.

    2010-01-01

    This paper presents a review of the available literature covering the latest module aspects of different photovoltaic/thermal (PV/T) collectors and their performances in terms of electrical as well as thermal output. The review covers detailed description of flat-plate and concentrating PV/T systems, using liquid or air as the working fluid, numerical model analysis, experimental work and qualitative evaluation of thermal and electrical output. Also an in-depth review on the performance parameters such as, optimum mass flow rate, PV/T dimensions, air channel geometry is presented in this study. Based on the thorough review, it is clear that PV/T modules are very promising devices and there exists lot of scope to further improve their performances. Appropriate recommendations are made which will aid PV/T systems to improve their efficiency and reducing their cost, making them more competitive in the present market. (author)

  4. Photovoltaic thermal module concepts and their performance analysis: A review

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, M. Arif; Sumathy, K. [Department of Mechanical Engineering, North Dakota State University, Fargo, ND (United States)

    2010-09-15

    This paper presents a review of the available literature covering the latest module aspects of different photovoltaic/thermal (PV/T) collectors and their performances in terms of electrical as well as thermal output. The review covers detailed description of flat-plate and concentrating PV/T systems, using liquid or air as the working fluid, numerical model analysis, experimental work and qualitative evaluation of thermal and electrical output. Also an in-depth review on the performance parameters such as, optimum mass flow rate, PV/T dimensions, air channel geometry is presented in this study. Based on the thorough review, it is clear that PV/T modules are very promising devices and there exists lot of scope to further improve their performances. Appropriate recommendations are made which will aid PV/T systems to improve their efficiency and reducing their cost, making them more competitive in the present market. (author)

  5. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  6. Analyzing Thermal Module Developments and Trends in High-Power LED

    Directory of Open Access Journals (Sweden)

    Jung-Chang Wang

    2014-01-01

    Full Text Available The solid-state light emitting diode (SSLED has been verified as consumer-electronic products and attracts attention to indoor and outdoor lighting lamp, which has a great benefit in saving energy and environmental protection. However, LED junction temperature will influence the luminous efficiency, spectral color, life cycle, and stability. This study utilizes thermal performance experiments with the illumination-analysis method and window program (vapour chamber thermal module, VCTM V1.0 to investigate and analyze the high-power LED (Hi-LED lighting thermal module, in order to achieve the best solution of the fin parameters under the natural convection. The computing core of the VCTM program employs the theoretical thermal resistance analytical approach with iterative convergence stated in this study to obtain a numerical solution. Results showed that the best geometry of thermal module is 4.4 mm fin thickness, 9.4 mm fin pitch, and 37 mm fin height with the LED junction temperature of 58.8°C. And the experimental thermal resistances are in good agreement with the theoretical thermal resistances; calculating error between measured data and simulation results is no more than ±7%. Thus, the Hi-LED illumination lamp has high life cycle and reliability.

  7. Measurements of Silicon Detector Thermal Runaway

    CERN Document Server

    Heusch, C A; Moser, H G

    1999-01-01

    We measured thermal runaway properties of previously irradiated silicon detectors cooled by TPG bars. We simulated their expected behaviour to measure the energy gap in the detector material and to test the validity of various underlying assumptions.

  8. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I; Araujo, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, C. P. 98060, Zacatecas, Zac. (Mexico); Marin, E, E-mail: emarin63@yahoo.e, E-mail: emarinm@ipn.m [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Instituto Politecnico Nacional, LegarIa 694, Colonia Irrigacion, C. P. 11500, Mexico D. F. (Mexico)

    2010-06-09

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  9. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    International Nuclear Information System (INIS)

    Ivanov, R; Moreno, I; Araujo, C; Marin, E

    2010-01-01

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  10. Longitudinal On-Column Thermal Modulation for Comprehensive Two-Dimensional Liquid Chromatography.

    Science.gov (United States)

    Creese, Mari E; Creese, Mathew J; Foley, Joe P; Cortes, Hernan J; Hilder, Emily F; Shellie, Robert A; Breadmore, Michael C

    2017-01-17

    Longitudinal on-column thermal modulation for comprehensive two-dimensional liquid chromatography is introduced. Modulation optimization involved a systematic investigation of heat transfer, analyte retention, and migration velocity at a range of temperatures. Longitudinal on-column thermal modulation was realized using a set of alkylphenones and compared to a conventional valve-modulator employing sample loops. The thermal modulator showed a reduced modulation-induced pressure impact than valve modulation, resulting in reduced baseline perturbation by a factor of 6; yielding a 6-14-fold improvement in signal-to-noise. A red wine sample was analyzed to demonstrate the potential of the longitudinal on-column thermal modulator for separation of a complex sample. Discrete peaks in the second dimension using the thermal modulator were 30-55% narrower than with the valve modulator. The results shown herein demonstrate the benefits of an active focusing modulator, such as reduced detection limits and increased total peak capacity.

  11. Peltier coefficient measurement in a thermoelectric module

    International Nuclear Information System (INIS)

    Garrido, Javier; Casanovas, Alejandro; Chimeno, José María

    2013-01-01

    A new method for measuring the Peltier coefficient in a thermocouple X/Y based on the energy balance at the junction has been proposed recently. This technique needs only the hot and cold temperatures of a thermoelectric module when an electric current flows through it as the operational variables. The temperature evolutions of the two module sides provide an evident and accurate idea of the Peltier effect. From these temperatures, the heat transfer between the module and the ambient is also evaluated. The thermoelectric phenomena are described in the framework of an observable theory. Based on this procedure, an experiment is presented for a university teaching laboratory at the undergraduate level. (paper)

  12. Thermal modelling of PV module performance under high ambient temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Diarra, D.C.; Harrison, S.J. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mechanical and Materials Engineering Solar Calorimetry Lab; Akuffo, F.O. [Kwame Nkrumah Univ. of Science and Technology, Kumasi (Ghana). Dept. of Mechanical Engineering

    2005-07-01

    When predicting the performance of photovoltaic (PV) generators, the actual performance is typically lower than test results conducted under standard test conditions because the radiant energy absorbed in the module under normal operation raises the temperature of the cell and other multilayer components. The increase in temperature translates to a lower conversion efficiency of the solar cells. In order to address these discrepancies, a thermal model of a characteristic PV module was developed to assess and predict its performance under real field-conditions. The PV module consisted of monocrystalline silicon cells in EVA between a glass cover and a tedlar backing sheet. The EES program was used to compute the equilibrium temperature profile in the PV module. It was shown that heat is dissipated towards the bottom and the top of the module, and that its temperature can be much higher than the ambient temperature. Modelling results indicate that 70-75 per cent of the absorbed solar radiation is dissipated from the solar cells as heat, while 4.7 per cent of the solar energy is absorbed in the glass cover and the EVA. It was also shown that the operating temperature of the PV module decreases with increased wind speed. 2 refs.

  13. Quantitative subsurface analysis using frequency modulated thermal wave imaging

    Science.gov (United States)

    Subhani, S. K.; Suresh, B.; Ghali, V. S.

    2018-01-01

    Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

  14. KMRR thermal power measurement error estimation

    International Nuclear Information System (INIS)

    Rhee, B.W.; Sim, B.S.; Lim, I.C.; Oh, S.K.

    1990-01-01

    The thermal power measurement error of the Korea Multi-purpose Research Reactor has been estimated by a statistical Monte Carlo method, and compared with those obtained by the other methods including deterministic and statistical approaches. The results show that the specified thermal power measurement error of 5% cannot be achieved if the commercial RTDs are used to measure the coolant temperatures of the secondary cooling system and the error can be reduced below the requirement if the commercial RTDs are replaced by the precision RTDs. The possible range of the thermal power control operation has been identified to be from 100% to 20% of full power

  15. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    DEFF Research Database (Denmark)

    Wu, Rui; Wang, Huai; Ma, Ke

    2014-01-01

    Thermal impedance of IGBT modules may vary with operating conditions due to that the thermal conductivity and heat capacity of materials are temperature dependent. This paper proposes a Cauer thermal model for a 1700 V/1000 A IGBT module with temperature-dependent thermal resistances and thermal ...... relevant reliability aspect performance. A test bench is built up with an ultra-fast infrared (IR) camera to validate the proposed thermal impedance model....

  16. Electrochemical-thermal Modeling to Evaluate Active Thermal Management of a Lithium-ion Battery Module

    International Nuclear Information System (INIS)

    Bahiraei, Farid; Fartaj, Amir; Nazri, Gholam-Abbas

    2017-01-01

    Lithium-ion batteries are commonly used in hybrid electric and full electric vehicles (HEV and EV). In HEV, thermal management is a strict requirement to control the batteries temperature within an optimal range in order to enhance performance, safety, reduce cost, and prolong the batteries lifetime. The optimum design of a thermal management system depends on the thermo-electrochemical behavior of the batteries, operating conditions, and weight and volume constraints. The aim of this study is to investigate the effects of various operating and design parameters on the thermal performance of a battery module consisted of six building block cells. An electrochemical-thermal model coupled to conjugate heat transfer and fluid dynamics simulations is used to assess the effectiveness of two indirect liquid thermal management approaches under the FUDC driving cycle. In this study, a novel pseudo 3D electrochemical-thermal model of the battery is used. It is found that the cooling plate thickness has a significant effect on the maximum and gradient of temperature in the module. Increasing the Reynolds number decreases the average temperature but at the expense of temperature uniformity. The results show that double channel cooling system has a lower maximum temperature and more uniform temperature distribution compared to a single channel cooling system.

  17. Conditioned pain modulation dampens the thermal grill illusion.

    Science.gov (United States)

    Harper, D E; Hollins, M

    2017-10-01

    The thermal grill illusion (TGI) refers to the perception of burning heat and often pain that arises from simultaneous cutaneous application of innocuous warm and cool stimuli. This study utilized conditioned pain modulation (CPM) to help elucidate the TGI's underlying neural mechanisms, including the debated role of ascending nociceptive signals in generating the illusion. To trigger CPM, subjects placed the left hand in noxious cold (6 °C) water before placing the right volar forearm onto a thermal grill. Lower pain and unpleasantness ratings of the grill in this CPM run compared to those in a control run (i.e. 33 °C water) were taken as evidence of CPM. To determine whether CPM reduces noxious heat pain and illusory heat pain equally, an experimental group of subjects rated pain and unpleasantness of a grill consisting of innocuous alternating warm (42 °C) and cool (18 °C) bars, while a control group rated a grill with all bars controlled to a noxious temperature (45 °C). CPM produced significant and comparable reductions in pain, unpleasantness and perceived heat of both noxious heat and the TGI. This result suggests that the TGI results from signals in nociceptive dorsal horn convergent neurons, since CPM involves descending inhibition with high selectivity for this neuronal population. More broadly, CPM's ability to produce a shift in perceived thermal sensation of both noxious heat and the TGI from 'hot' to 'warm' implies that nociceptive signals generated by a cutaneous stimulus can contribute to its perceived thermal intensity. Conditioned pain modulation reduces the perceived painfulness, unpleasantness and heat of the thermal grill illusion and noxious heat similarly. The results have important theoretical implications for both types of pain. © 2017 European Pain Federation - EFIC®.

  18. A Method for testing the integrated thermal resistance of thermoelectric modules

    Science.gov (United States)

    Gao, Junling; Du, Qungui; Chen, Min

    2013-11-01

    The integrated thermal resistance (ITR) of thermoelectric modules (TEMs) is an important parameter that represents the thermal-conduction of ceramic substrates, copper conducting strips, and welding material used in the TEM as well as the thermal contact resistances between different materials. In this study, an accurate and practical test method is proposed for the ITR of TEMs according to thermoelectric heat transfer theory and the equivalent characteristics of heat flux through the cold and hot sides of TEMs in an open-circuit situation. By using such measurements and comparisons, it is verified that the measured ITR value in our mode is accurate and reliable. In particular this method accurately predicts the actual operating conditions of TEMs, in which TEMs are under certain mechanical pressure. It effectively solves the problem of thermal resistance extraction from operating TEMs and is of great significance in their analysis and optimization.

  19. Thermal equilibrium control by frequent bang-bang modulation.

    Science.gov (United States)

    Yang, Cheng-Xi; Wang, Xiang-Bin

    2010-05-01

    In this paper, we investigate the non-Markovian heat transfer between a weakly damped harmonic oscillator (system) and a thermal bath. When the system is initially in a thermal state and not correlated with the environment, the mean energy of the system always first increases, then oscillates, and finally reaches equilibrium with the bath, no matter what the initial temperature of the system is. Moreover, the heat transfer between the system and the bath can be controlled by fast bang-bang modulation. This modulation does work on the system, and temporarily inverts the direction of heat flow. In this case, the common sense that heat always transfers from hot to cold does not hold any more. At the long time scale, a new dynamic equilibrium is established between the system and the bath. At this equilibrium, the energy of the system can be either higher or lower than its normal equilibrium value. A comprehensive analysis of the relationship between the dynamic equilibrium and the parameters of the modulation as well as the environment is presented.

  20. Measurement of thermal neutron capture cross section

    International Nuclear Information System (INIS)

    Huang Xiaolong; Han Xiaogang; Yu Weixiang; Lu Hanlin; Zhao Wenrong

    2001-01-01

    The thermal neutron capture cross sections of 71 Ga(n, γ) 72 Ga, 94 Zr(n, γ) 95 Zr and 191 Ir(n, γ) 192 Ir m1+g,m2 reactions were measured by using activation method and compared with other measured data. Meanwhile the half-life of 72 Ga was also measured. The samples were irradiated with the neutron in the thermal column of heavy water reactor of China Institute of Atomic Energy. The activities of the reaction products were measured by well-calibrated Ge(Li) detector

  1. Thermal neutron albedo measurements for multilithic reflectors

    International Nuclear Information System (INIS)

    Mehboob, Khurram; Ahmed, Raheel; Ali, Majid; Tabassam, Uzma

    2013-01-01

    Highlights: • Measurement of thermal neuron albedo for multilithic reflectors. • Modeling of experiments in MATLAB. • Comparison of numerical calculated and experimental values. • Study of thermal neutron albedo in different multilayered shielding. - Abstract: An experimental measurement of the thermal neutron (0.025 eV) albedo (αth) has been carried out for multilithic shielding by using Am–Be neutron source and BF 3 detector. The measured saturation value for the thermal albedo of paraffin wax has been found to be 0.734 ± 0.020, which is in close agreement to the corresponding value 0.83 quoted in the literature. The thermal neutron albedo has been measured for the multilayered shielding in copper–wood, copper–aluminum, wood–paraffin and paraffin–iron combinations in horizontal geometric configurations. Modeling and numerical simulation have been carried out by developing a MATLAB code which solves the diffusion equation in order to calculate the experimental results. Good agreement has been found between the numerical calculated and experimental results. The uncertainties in the measurements have also been calculated based on error propagation of the underlying Poisson distribution

  2. Effective Thermal Analysis of Using Peltier Module for Desalination Process

    Directory of Open Access Journals (Sweden)

    Hayder Al-Madhhachi

    2018-01-01

    Full Text Available The key objective of this study is to analyse the heat transfer processes involved in the evaporation and condensation of water in a water distillation system employing a thermoelectric module. This analysis can help to increase the water production and to enhance the system performance. For the analysis, a water distillation unit prototype integrated with a thermoelectric module was designed and fabricated. A theoretical model is developed to study the effect of the heat added, transferred and removed, in forced convection and laminar flow, during the evaporation and condensation processes. The thermoelectric module is used to convert electricity into heat under Peltier effect and control precisely the absorbed and released heat at the cold and hot sides of the module, respectively. Temperatures of water, vapour, condenser, cold and hot sides of the thermoelectric module and water production have been measured experimentally under steady state operation. The theoretical and experimental water production were found to be in agreement. The amount of heat that needs to be evaporated from water-vapour interface and transferred through the condenser surface to the thermoelectric module is crucial for the design and optimization of distillation systems.

  3. Thermal conductivity measurements of pacific illite sediment

    Science.gov (United States)

    Hickox, C. E.; McVey, D. F.; Miller, J. B.; Olson, L. O.; Silva, A. J.

    1986-07-01

    Results are reported for effective thermal conductivity measurements performed in situ and in core samples of illite marine sediment. The measurements were obtained during a recent oceanographic expedition to a study site in the north central region of the Pacific Ocean. This study was undertaken in support of the U.S. Subseabed Disposal Project, the purpose of which is to investigate the scientific feasibility of using the fine-grained sediments of the sea floor as a repository for high-level nuclear waste. In situ measurements were made and 1.5-m-long hydrostatic piston cores were taken, under remote control, from a platform that was lowered to the sea floor, 5844 m below sea level. The in situ measurement of thermal conductivity was made at a nominal depth of 80 cm below the sediment surface using a specially developed, line-source, needle probe. Thermal conductivity measurements in three piston cores and one box core (obtained several kilometers from the study site) were made on shipboard using a miniature needle probe. The in situ thermal conductivity was approximately 0.91 W · m-1 · K-1. Values determined from the cores were within the range 0.81 to 0.89 W · m-1 · K-1.

  4. Thermal conductivity measurements of Pacific illite sediment

    International Nuclear Information System (INIS)

    Hickox, C.E.; McVey, D.F.; Miller, J.B.; Olson, L.O.; Silva, A.J.

    1986-01-01

    Results are reported for effective thermal conductivity measurements performed in situ and in core samples of illite marine sediment. The measurements were obtained during a recent oceanographic expedition to a study site in the north central region of the Pacific Ocean. This study was undertaken in support of the US Subseabed Disposal Project, the purpose of which is to investigate the scientific feasibility of using the fine grained sediments of the sea floor as a repository for high level nuclear waste. In situ measurements were made and 1.5-meter long hydrostatic piston cores were taken, under remote control, from a platform that was lowered to the sea floor, 5844 m below sea level. The in situ measurement of thermal conductivity was made at a nominal depth of 80 cm below the sediment surface using a specially developed, line source, needle probe. Thermal conductivity measurements in three piston cores and one box core (obtained several kilometers from the study site) were made on shipboard using a miniature needle probe. The in situ thermal conductivity was approximately 0.91 W/m.K. Values determined from the cores were within the range 0.81 to 0.89 W/m.K

  5. EXPERIMENTAL MEASUREMENT OF NANOFLUIDS THERMAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Adnan M. Hussein

    2013-07-01

    Full Text Available Solid particles dispersed in a liquid with sizes no larger than 100nm, known as nanofluids, are used to enhance Thermophysical properties compared to the base fluid. Preparations of alumina (Al2O3, titania (TiO2 and silica (SiO2 in water have been experimentally conducted in volume concentrations ranging between 1 and 2.5%. Thermal conductivity is measured by the hot wire method and viscosity with viscometer equipment. The results of thermal conductivity and viscosity showed an enhancement (0.5–20% and 0.5–60% respectively compared with the base fluid. The data measured agreed with experimental data of other researchers with deviation of less than 5%. The study showed that alumina has the highest thermal conductivity, followed silica and titania, on the other hand silica has the highest viscosity followed alumina and titania.

  6. A non-destructive method to measure the thermal properties of frozen soils during phase transition

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2015-04-01

    Full Text Available Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energy balances affecting the climate. Measurement of the thermal properties of frozen soils during phase transition is important for analyzing the thermal transport process. Due to the involvement of phase transition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of a multifunctional instrument that integrates time domain reflectometry (TDR sensor and thermal pulse technology (TPT to measure the thermal properties of soil during phase transition. With this method, the extent of phase transition (freezing/thawing was measured with the TDR module; and the corresponding thermal properties were measured with the TPT module. Therefore, the variation of thermal properties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate the performance of this measurement method. The performance of individual modules was first validated with designed experiments. The new sensor was then used to monitor the properties of soils during freezing–thawing process, from which the freezing/thawing degree and thermal properties were simultaneously measured. The results are consistent with documented trends of thermal properties variations.

  7. Measurements of thermal properties of rocks

    International Nuclear Information System (INIS)

    Kumada, Toshiaki

    2001-02-01

    The report concerns the measurement of thermal conductivity and specific heat of supplied sedimental rock B and Funyu rock. The method of measurement of these properties was done with the method which was developed at 1997 and improved much in its accuracy by the present author et al. The porosity of sedimental rock B is 0.55, which is deduced from the density of rock (the porosity deduced from the difference between dry and water filled conditions is 0.42) and the shape and size of pores in rock are much different. Its thermal conductivity is 0.238 W/mK in dry and 1.152 W/mK in water filled conditions respectively, while the thermal conductivity of bentonite is 0.238 W/mK in dry and 1.152 W/mK in water saturated conditions. The difference of thermal conductivity between dry and water saturated conditions is little difference in sedimental rock B and bentonite at same porosity. The porosity of Funyu rock is 0.26 and the shape and size of pores in the rock are uniform. Its thermal conductivity is 0.914 W/mK in dry and 1.405 W/mK in water saturated conditions, while the thermal conductivity of bentonite is 0.606 W/mK in dry and 1.591 W/mK in water saturated conditions respectively. The correlation estimating thermal conductivity of rocks was derived based on Fricke correlation by presuming rocks as a suspension. (author)

  8. Temperature-modulated direct thermoelectric gas sensors: thermal modeling and results for fast hydrocarbon sensors

    International Nuclear Information System (INIS)

    Rettig, Frank; Moos, Ralf

    2009-01-01

    Direct thermoelectric gas sensors are a promising alternative to conductometric gas sensors. For accurate results, a temperature modulation technique in combination with a regression analysis is advantageous. However, the thermal time constant of screen-printed sensors is quite large. As a result, up to now the temperature modulation frequency (20 mHz) has been too low and the corresponding principle-related response time (50 s) has been too high for many applications. With a special design, respecting the physical properties of thermal waves and the use of signal processing similar to a lock-in-amplifier, it is possible to achieve response times of about 1 s. As a result, direct thermoelectric gas sensors with SnO 2 as a gas-sensitive material respond fast and are reproducible to the propane concentration in the ambient atmosphere. Due to the path-independent behavior of the thermovoltage and the temperature, the measured thermopower of two sensors is almost identical

  9. Thermal effects in shales: measurements and modeling

    International Nuclear Information System (INIS)

    McKinstry, H.A.

    1977-01-01

    Research is reported concerning thermal and physical measurements and theoretical modeling relevant to the storage of radioactive wastes in a shale. Reference thermal conductivity measurements are made at atmospheric pressure in a commercial apparatus; and equipment for permeability measurements has been developed, and is being extended with respect to measurement ranges. Thermal properties of shales are being determined as a function of temperature and pressures. Apparatus was developed to measure shales in two different experimental configurations. In the first, a disk 15 mm in diameter of the material is measured by a steady state technique using a reference material to measure the heat flow within the system. The sample is sandwiched between two disks of a reference material (single crystal quartz is being used initially as reference material). The heat flow is determined twice in order to determine that steady state conditions prevail; the temperature drop over the two references is measured. When these indicate an equal heat flow, the thermal conductivity of the sample can be calculated from the temperature difference of the two faces. The second technique is for determining effect of temperature in a water saturated shale on a larger scale. Cylindrical shale (or siltstone) specimens that are being studied (large for a laboratory sample) are to be heated electrically at the center, contained in a pressure vessel that will maintain a fixed water pressure around it. The temperature is monitored at many points within the shale sample. The sample dimensions are 25 cm diameter, 20 cm long. A micro computer system has been constructed to monitor 16 thermocouples to record variation of temperature distribution with time

  10. Measuring Thermal Conductivity at LH2 Temperatures

    Science.gov (United States)

    Selvidge, Shawn; Watwood, Michael C.

    2004-01-01

    For many years, the National Institute of Standards and Technology (NIST) produced reference materials for materials testing. One such reference material was intended for use with a guarded hot plate apparatus designed to meet the requirements of ASTM C177-97, "Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus." This apparatus can be used to test materials in various gaseous environments from atmospheric pressure to a vacuum. It allows the thermal transmission properties of insulating materials to be measured from just above ambient temperature down to temperatures below liquid hydrogen. However, NIST did not generate data below 77 K temperature for the reference material in question. This paper describes a test method used at NASA's Marshall Space Flight Center (MSFC) to optimize thermal conductivity measurements during the development of thermal protection systems. The test method extends the usability range of this reference material by generating data at temperatures lower than 77 K. Information provided by this test is discussed, as are the capabilities of the MSFC Hydrogen Test Facility, where advanced methods for materials testing are routinely developed and optimized in support of aerospace applications.

  11. Thermal cycling fatigue of organic thermal interface materials using a thermal-displacement measurement technique

    Science.gov (United States)

    Steill, Jason Scott

    The long term reliability of polymer-based thermal interface materials (TIM) is essential for modern electronic packages which require robust thermal management. The challenge for today's materials scientists and engineers is to maximize the heat flow from integrated circuits through a TIM and out the heat sink. Thermal cycling of the electronic package and non-uniformity in the heat flux with respect to the plan area can lead to void formation and delamination which re-introduces inefficient heat transfer. Measurement and understanding at the nano-scale is essential for TIM development. Finding and documenting the evolution of the defects is dependent upon a full understanding of the thermal probes response to changing environmental conditions and the effects of probe usage. The response of the thermal-displacement measurement technique was dominated by changes to the environment. Accurate measurement of the thermal performance was hindered by the inability to create a model system and control the operating conditions. This research highlights the need for continued study into the probe's thermal and mechanical response using tightly controlled test conditions.

  12. Thermally modulated nano-trampoline material as smart skin for gas molecular mass detection

    Science.gov (United States)

    Xia, Hua

    2012-06-01

    Conventional multi-component gas analysis is based either on laser spectroscopy, laser and photoacoustic absorption at specific wavelengths, or on gas chromatography by separating the components of a gas mixture primarily due to boiling point (or vapor pressure) differences. This paper will present a new gas molecular mass detection method based on thermally modulated nano-trampoline material as smart skin for gas molecular mass detection by fiber Bragg grating-based gas sensors. Such a nanomaterial and fiber Bragg grating integrated sensing device has been designed to be operated either at high-energy level (highly thermal strained status) or at low-energy level (low thermal strained status). Thermal energy absorption of gas molecular trigs the sensing device transition from high-thermal-energy status to low-thermal- energy status. Experiment has shown that thermal energy variation due to gas molecular thermal energy absorption is dependent upon the gas molecular mass, and can be detected by fiber Bragg resonant wavelength shift with a linear function from 17 kg/kmol to 32 kg/kmol and a sensitivity of 0.025 kg/kmol for a 5 micron-thick nano-trampoline structure and fiber Bragg grating integrated gas sensing device. The laboratory and field validation data have further demonstrated its fast response characteristics and reliability to be online gas analysis instrument for measuring effective gas molecular mass from single-component gas, binary-component gas mixture, and multi-gas mixture. The potential industrial applications include fouling and surge control for gas charge centrifugal compressor ethylene production, gas purity for hydrogen-cooled generator, gasification for syngas production, gasoline/diesel and natural gas fuel quality monitoring for consumer market.

  13. Three-Dimensional Modeling of the Thermal Behavior of a Lithium-Ion Battery Module for Hybrid Electric Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Jaeshin Yi

    2014-11-01

    Full Text Available This paper reports a modeling methodology to predict the effects of operating conditions on the thermal behavior of a lithium-ion battery (LIB module. The potential and current density distributions on the electrodes of an LIB cell are predicted as a function of discharge time based on the principle of charge conservation. By using the modeling results of the potential and current density distributions of the LIB cell, the non-uniform distribution of the heat generation rate in a single LIB cell within the module is calculated. Based on the heat generation rate in the single LIB cell determined as a function of the position on the electrode and time, a three-dimensional thermal modeling of an LIB module is performed to calculate the three-dimensional velocity, pressure, and temperature distributions within the LIB module as a function of time at various operating conditions. Thermal modeling of an LIB module is validated by the comparison between the experimental measurements and the modeling results. The effect of the cooling condition of the LIB module on the temperature rise of the LIB cells within the module and the uniformity of the distribution of the cell temperatures are analyzed quantitatively based on the modeling results.

  14. Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

    Directory of Open Access Journals (Sweden)

    Strąkowska Maria

    2016-09-01

    Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

  15. Measurement of Thermal Radiation Properties of Solids

    Science.gov (United States)

    Richmond, J. C. (Editor)

    1963-01-01

    The overall objectives of the Symposium were to afford (1) an opportunity for workers in the field to describe the equipment and procedures currently in use for measuring thermal radiation properties of solids, (2) an opportunity for constructive criticism of the material presented, and (3) an open forum for discussion of mutual problems. It was also the hope of the sponsors that the published proceedings of the Symposium would serve as a valuable reference on measurement techniques for evaluating thermal radiation properties of solids, partic.ularly for those with limited experience in the field. Because of the strong dependence of emitted flux upon temperature, the program committee thought it advisable to devote the first session to a discussion of the problems of temperature measurement. All of the papers in Session I were presented at the request of and upon topics suggested by the Committee. Because of time and space limitations, it, was impossible to consider all temperature measurement problems that might arise--the objective was rather to call to the attention of the reader some of the problems that might be encountered, and to provide references that might provide solutions.

  16. 47 CFR 2.1047 - Measurements required: Modulation characteristics.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Measurements required: Modulation characteristics. 2.1047 Section 2.1047 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY... Certification § 2.1047 Measurements required: Modulation characteristics. (a) Voice modulated communication...

  17. Thermal Modeling of NUHOMS HSM-15 and HSM-1 Storage Modules at Calvert Cliffs Nuclear Power Station ISFSI

    Energy Technology Data Exchange (ETDEWEB)

    Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.; Cuta, Judith M.; Collins, Brian A.; Siciliano, Edward R.

    2012-10-01

    As part of the Used Fuel Disposition Campaign of the Department of Energy (DOE), visual inspections and temperature measurements were performed on two storage modules in the Calvert Cliffs Nuclear Power Station’s Independent Spent Fuel Storage Installation (ISFSI). Detailed thermal models models were developed to obtain realistic temperature predictions for actual storage systems, in contrast to conservative and bounding design basis calculations.

  18. Experimental research of limits for thermal modulation transfer function

    Directory of Open Access Journals (Sweden)

    Tomić Ljubiša D.

    2009-01-01

    Full Text Available The paper presented testing of surface defects by pulse video thermography techniques. Such techniques rely on transient infrared radiation from the sample heated by the short duration flux initiated by flesh. Experimental measurements are realized by infrared sensor (FLIR camera. Testing results are considered for the samples with controlled designed defects beyond observed surfaces. The effects of response through the transparent wall are measured as infrared visible radiance. Researches with controlled samples are performed to verify visibility threshold of defect dimensions and forms, for possible use as modulation transfer function of defects hidden beyond the surfaces of thin metal walls. Dimensionless coefficients are derived for method estimations as the results from experimental research.

  19. Thermal lens measurements in the cornea.

    Science.gov (United States)

    Venkatesh, S; Guthrie, S; Cruickshank, F R; Bailey, R T; Foulds, W S; Lee, W R

    1985-02-01

    Q-switched pulses from a neodymium/YAG (yttrium-aluminium-garnet) laser were passed through corneal discs taken from the enucleated eyes of three baboons and four rabbits. The time course of heat dissipation following absorption of laser energy by the tissue was studied with the use of a second continuous wave laser beam acting as a probe. It was found that the absorption of each neodymium/YAG pulse created a transient divergent lens within the cornea as theoretical considerations predicted. The relaxation time that characterised the decay of this thermal lens for a 1/e laser beam diameter of 2.0 mm was found to be 2.3 +/- 0.1 s (mean +/- standard error for 12 separate groups of measurements). Our results show that Q-switched laser pulses passing through apparently unaffected transparent tissues can induce thermal lens effects which persist for several seconds. The optical transfer of each pulse in a stream will be identical only if enough time is left between pulses for the tissues to return to their initial state. Therefore, when such laser pulses sharply focused to perform high precision intraocular surgery are used, thermal lensing in the transparent ocular media must limit the rate at which pulses can be usefully delivered.

  20. Measuring Thermal Characteristics of Urban Landscapes

    Science.gov (United States)

    Luvall, Jeffrey C.; Quattrochi, Dale A.; Rickman, Doug L.

    1999-01-01

    The additional heating of the air over the city is the result of the replacement of naturally vegetated surfaces with those composed of asphalt, concrete, rooftops and other man-made materials. The temperatures of these artificial surfaces can be 20 to 40 C higher than vegetated surfaces. Materials such as asphalt store much of the sun's energy and remains hot long after sunset. This produces a dome of elevated air temperatures 5 to 8 C greater over the city, compared to the air temperatures over adjacent rural areas. This effect is called the "urban heat island". Urban landscapes are a complex mixture of vegetated and nonvegetated surfaces. It is difficult to take enough temperature measurements over a large city area to characterize the complexity of urban radiant surface temperature variability. However, the use of remotely sensed thermal data from airborne scanners are ideal for the task. In a study funded by NASA, a series of flights over Huntsville, Alabama were performed in September 1994 and over Atlanta, Georgia in May 1997. Analysis of thermal energy responses for specific or discrete surfaces typical of the urban landscape (e.g., asphalt, building rooftops, vegetation) requires measurements at a very fine spatial scale (i.e., energy regimes. Additionally, very fine scale spatial resolution thermal infrared data, such as that obtained from aircraft, are very useful for demonstrating to planning officials, policy makers, and the general populace, what the benefits are of the urban forest in both mitigating the urban heat island effect, in making cities more aesthetically pleasing and more habitable environments, and in overall cooling of the community. In this presentation we will examine the techniques of analyzing remotely sensed data for measuring the effect of various urban surfaces on their contribution to the urban heat island effect.

  1. Pressure measurement using thermal properties of materials

    International Nuclear Information System (INIS)

    Cruz Pessoa, Jose Dalton; Calbo, Adonai Gimenes

    2004-01-01

    This work presents a design and two methods, one isothermal and one isovolumetric, for pressure measurements based on the compressibility coefficient (κ) and thermal expansibility (α) of the fluid under test. The setup and relevant construction details are described. To demonstrate the applicability of the isovolumetric measurement method, the setup was calibrated with respect to a Bourdon-type manometer; the other isothermic method was analyzed to determine construction details that could realize resolution requirements. The authors determined the effect of ambient temperature on device operation and the time response of the isovolumetric method. The device can be used to estimate the compressibility of a fluid and, in addition, could become an alternative for direct plant cell turgor measurement

  2. Thermal and optical performance of encapsulation systems for flat-plate photovoltaic modules

    Science.gov (United States)

    Minning, C. P.; Coakley, J. F.; Perrygo, C. M.; Garcia, A., III; Cuddihy, E. F.

    1981-01-01

    The electrical power output from a photovoltaic module is strongly influenced by the thermal and optical characteristics of the module encapsulation system. Described are the methodology and computer model for performing fast and accurate thermal and optical evaluations of different encapsulation systems. The computer model is used to evaluate cell temperature, solar energy transmittance through the encapsulation system, and electric power output for operation in a terrestrial environment. Extensive results are presented for both superstrate-module and substrate-module design schemes which include different types of silicon cell materials, pottants, and antireflection coatings.

  3. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.; Yang, P.E.; Lin, Y.P.; Lin, B.Y.; Chen, H.J.; Lai, R.C.; Cheng, J.S.

    2011-01-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well

  4. Calibration-free absolute frequency response measurement of directly modulated lasers based on additional modulation.

    Science.gov (United States)

    Zhang, Shangjian; Zou, Xinhai; Wang, Heng; Zhang, Yali; Lu, Rongguo; Liu, Yong

    2015-10-15

    A calibration-free electrical method is proposed for measuring the absolute frequency response of directly modulated semiconductor lasers based on additional modulation. The method achieves the electrical domain measurement of the modulation index of directly modulated lasers without the need for correcting the responsivity fluctuation in the photodetection. Moreover, it doubles measuring frequency range by setting a specific frequency relationship between the direct and additional modulation. Both the absolute and relative frequency response of semiconductor lasers are experimentally measured from the electrical spectrum of the twice-modulated optical signal, and the measured results are compared to those obtained with conventional methods to check the consistency. The proposed method provides calibration-free and accurate measurement for high-speed semiconductor lasers with high-resolution electrical spectrum analysis.

  5. Measuring Thermal Characteristics of Urban Landscapes

    Science.gov (United States)

    Luvall, Jeffrey C.; Quattrochi, Dale A.; Rickman, Doug L.

    1999-01-01

    The additional heating of the air over the city is the result of the replacement of naturally vegetated surfaces with those composed of asphalt, concrete, rooftops and other man-made materials. The temperatures of these artificial surfaces can be 20 to 40 C higher than vegetated surfaces. Materials such as asphalt store much of the sun's energy and remains hot long after sunset. This produces a dome of elevated air temperatures 5 to 8 C greater over the city, compared to the air temperatures over adjacent rural areas. This effect is called the "urban heat island". Urban landscapes are a complex mixture of vegetated and nonvegetated surfaces. It is difficult to take enough temperature measurements over a large city area to characterize the complexity of urban radiant surface temperature variability. However, the use of remotely sensed thermal data from airborne scanners are ideal for the task. In a study funded by NASA, a series of flights over Huntsville, Alabama were performed in September 1994 and over Atlanta, Georgia in May 1997. Analysis of thermal energy responses for specific or discrete surfaces typical of the urban landscape (e.g., asphalt, building rooftops, vegetation) requires measurements at a very fine spatial scale (i.e., urban forest in both mitigating the urban heat island effect, in making cities more aesthetically pleasing and more habitable environments, and in overall cooling of the community. In this presentation we will examine the techniques of analyzing remotely sensed data for measuring the effect of various urban surfaces on their contribution to the urban heat island effect.

  6. Strain measurements during pressurized thermal shock experiment

    International Nuclear Information System (INIS)

    Tarso Vida Gomes, P. de; Julio Ricardo Barreto Cruz; Tanius Rodrigues Mansur; Denis Henrique Bianchi Scaldaferri; Miguel Mattar Neto

    2005-01-01

    For the life extension of nuclear power plants, the residual life of most of their components must be evaluated along all their operating time. Concerning the reactor pressure vessel, the pressurized thermal shock (PTS) is a very important event to be considered. For better understanding the effects of this kind of event, tests are made. The approach described here consisted of building a simplified in-scale physical model of the reactor pressure vessel, submitting it to the actual operating temperature and pressure conditions and provoking a thermal shock by means of cold water flow in its external surface. To conduct such test, the Nuclear Technology Development Center (CDTN) has been conducting several studies related to PTS and has also built a laboratory that has made possible the simulation of the PTS loading conditions. Several cracks were produced in the external surface of the reactor pressure vessel model. Strain gages were fixed by means of electrical discharge welding over the cracks regions in both external and internal surfaces. The temperature was monitored in 10 points across the vessel wall. The internal pressure was manually controlled and monitored using a pressure transducer. Two PTS experiments were conducted and this paper presents the strain measurement procedures applied to the reactor pressure vessel model, during the PTS, using strain gages experimental methodology. (authors)

  7. Experimental investigation of an optical water filter for Photovoltaic/Thermal conversion module

    International Nuclear Information System (INIS)

    Al-Shohani, Wisam A.M.; Sabouri, Aydin; Al-Dadah, Raya; Mahmoud, Saad; Butt, Haider

    2016-01-01

    Highlights: • New design of Photovoltaic/Thermal system is proposed. • Using the optical water layer as a spectrum splitter is tested experimentally. • Optical rig is developed to study the optical performance of water layer. • Energy conversion under different water layer thicknesses is determined. - Abstract: This paper presents an experimental investigation of a novel optical water filter used for Photovoltaic/Thermal and Concentrating Photovoltaic/Thermal modules. A water layer is used as a spectrum splitter of solar radiation placed above the photovoltaic cells and as a thermal working fluid simultaneously. The water layer absorbs the ultraviolet and part of infrared, which are not used by the photovoltaic, but transmits the visible and some of infrared to the solar cell surface which are used by the photovoltaic. In this work, the transmittance of the optical water filter was measured for different water thicknesses (1, 2, 3, 4, and 5 cm) and radiation wavelength ranging from 0.35 to 1 μm. Results show that there is a significant effect of the water layer thickness on the transmittance of the spectra where the transmittance decreases as the water layer increases. Moreover, energy conversion rate of photovoltaic with the optical water filter at different water layer thicknesses has been determined.

  8. The Measurement of Thermal Diffusivity in Conductor and Insulator by Photodeflection Technique

    Science.gov (United States)

    Achathongsuk, U.; Rittidach, T.; Tipmonta, P.; Kijamnajsuk, P.; Chotikaprakhan, S.

    2017-09-01

    The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

  9. A Module For Thermal Pest Control In Stored Raw Materials Used In ...

    African Journals Online (AJOL)

    Pests are heterogeneous both in space and time, creating gradients and patterns depending on the prevailing environmental variables. Pest control efforts have utilized manipulations of these variables. This project is ona module for thermal control of pests using the hitherto waste steam from the indusries. The module is an ...

  10. A Thermal Runaway Simulation on a Lithium Titanate Battery and the Battery Module

    Directory of Open Access Journals (Sweden)

    Man Chen

    2015-01-01

    Full Text Available Based on the electrochemical and thermal model, a coupled electro-thermal runaway model was developed and implemented using finite element methods. The thermal decomposition reactions when the battery temperature exceeds the material decomposition temperature were embedded into the model. The temperature variations of a lithium titanate battery during a series of charge-discharge cycles under different current rates were simulated. The results of temperature and heat generation rate demonstrate that the greater the current, the faster the battery temperature is rising. Furthermore, the thermal influence of the overheated cell on surrounding batteries in the module was simulated, and the variation of temperature and heat generation during thermal runaway was obtained. It was found that the overheated cell can induce thermal runaway in other adjacent cells within 3 mm distance in the battery module if the accumulated heat is not dissipated rapidly.

  11. A high-stability non-contact dilatometer for low-amplitude temperature-modulated measurements

    Energy Technology Data Exchange (ETDEWEB)

    Luckabauer, Martin; Sprengel, Wolfgang; Würschum, Roland [Institute of Materials Physics, Graz University of Technology, A-8010 Graz (Austria)

    2016-07-15

    Temperature modulated thermophysical measurements can deliver valuable insights into the phase transformation behavior of many different materials. While especially for non-metallic systems at low temperatures numerous powerful methods exist, no high-temperature device suitable for modulated measurements of bulk metallic alloy samples is available for routine use. In this work a dilatometer for temperature modulated isothermal and non-isothermal measurements in the temperature range from room temperature to 1300 K is presented. The length measuring system is based on a two-beam Michelson laser interferometer with an incremental resolution of 20 pm. The non-contact measurement principle allows for resolving sinusoidal length change signals with amplitudes in the sub-500 nm range and physically decouples the length measuring system from the temperature modulation and heating control. To demonstrate the low-amplitude capabilities, results for the thermal expansion of nickel for two different modulation frequencies are presented. These results prove that the novel method can be used to routinely resolve length-change signals of metallic samples with temperature amplitudes well below 1 K. This high resolution in combination with the non-contact measurement principle significantly extends the application range of modulated dilatometry towards high-stability phase transformation measurements on complex alloys.

  12. General 3D Lumped Thermal Model with Various Boundary Conditions for High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2016-01-01

    Accurate thermal dynamics modeling of high power Insulated Gate Bipolar Transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated...... thermal behaviors in the IGBTs. In this paper, a new three-dimensional (3D) lumped thermal model is proposed, which can easily be characterized from Finite Element Methods (FEM) based simulation and acquire the thermal distribution in critical points. Meanwhile the boundary conditions including...... the cooling system and power losses are modeled in the 3D thermal model, which can be adapted to different real field applications of power electronic converters. The accuracy of the proposed thermal model is verified by experimental results....

  13. Application of advanced thermal management technologies to the ATLAS SCT barrel module baseboards

    Energy Technology Data Exchange (ETDEWEB)

    Apsimon, R.J. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 OQX (United Kingdom); Batchelor, L.E. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 OQX (United Kingdom); Beck, G.A. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Canard, P. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Carter, A.A. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)]. E-mail: a.a.carter@qmul.ac.uk; Carter, J.R. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Davis, V.R. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 OQX (United Kingdom); Oliveira, R. de [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Gibson, M.D. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 OQX (United Kingdom); Hominal, L. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Ilie, D.M. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Ilie, S.D. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Leboube, C.G. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Mistry, J. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Morin, J. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Morris, J.; Nagai, K. [Department of Physics, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Sexton, I.; Thery, X. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland); Tyndel, M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 OQX (United Kingdom)

    2006-09-15

    The paper describes the application of advanced thermal management technologies to the design and production of the barrel module baseboard of the SemiConductor Tracker (SCT) of the ATLAS experiment at the Large Hadron Collider (LHC). The barrel modules contain silicon microstrip sensors and readout ASICs for tracking charged particles, and the baseboard forms the central element of the module, providing both its necessary thermal management and its mechanical structure. The baseboard requirements and specifications are given, and design and fabrication details are described. The properties of the 3000 baseboards successfully produced for the SCT are summarised.

  14. Effective Thermal Analysis of Using Peltier Module for Desalination Process

    OpenAIRE

    Hayder Al-Madhhachi

    2018-01-01

    The key objective of this study is to analyse the heat transfer processes involved in the evaporation and condensation of water in a water distillation system employing a thermoelectric module. This analysis can help to increase the water production and to enhance the system performance. For the analysis, a water distillation unit prototype integrated with a thermoelectric module was designed and fabricated. A theoretical model is developed to study the effect of the heat added, transferred a...

  15. Reducing Contact Resistance Errors In Measuring Thermal ...

    African Journals Online (AJOL)

    Values of thermal conductivity (k) of glass beads, quartz sand, stone dust and clay were determined using a thermal probe with and without heat sink compounds (arctic silver grease (ASG) and white grease (WG)) at different water contents, bulk densities and particle sizes. The heat sink compounds (HSC) increased k at ...

  16. Thermal conductivity engineering in width-modulated silicon nanowires and thermoelectric efficiency enhancement

    Science.gov (United States)

    Zianni, Xanthippi

    2018-03-01

    Width-modulated nanowires have been proposed as efficient thermoelectric materials. Here, the electron and phonon transport properties and the thermoelectric efficiency are discussed for dimensions above the quantum confinement regime. The thermal conductivity decreases dramatically in the presence of thin constrictions due to their ballistic thermal resistance. It shows a scaling behavior upon the width-modulation rate that allows for thermal conductivity engineering. The electron conductivity also decreases due to enhanced boundary scattering by the constrictions. The effect of boundary scattering is weaker for electrons than for phonons and the overall thermoelectric efficiency is enhanced. A ZT enhancement by a factor of 20-30 is predicted for width-modulated nanowires compared to bulk silicon. Our findings indicate that width-modulated nanostructures are promising for developing silicon nanostructures with high thermoelectric efficiency.

  17. Scaling behavior of the thermal conductivity of width-modulated nanowires and nanofilms for heat transfer control at the nanoscale.

    Science.gov (United States)

    Zianni, Xanthippi; Jean, Valentin; Termentzidis, Konstantinos; Lacroix, David

    2014-11-21

    We report on scaling behavior of the thermal conductivity of width-modulated nanowires and nanofilms that have been studied with the phonon Monte Carlo technique. It has been found that the reduction of the thermal conductivity scales with the nanostructure transmissivity, a property entirely determined by the modulation geometry, irrespectively of the material choice. Tuning of the thermal conductivity is possible by the nanostructure width-modulation without strict limitations for the modulation profile. In addition, a very significant constriction thermal resistance due to width-discontinuity has been identified, in analogy to the contact thermal resistance between two dissimilar materials. The constriction thermal resistance also scales with the modulated nanostructure transmissivity. Our conclusions are generic indicating that a wide range of materials can be used for the modulated nanostructures. Direct heat flow control can be provided by designing the nanostructure width-modulation.

  18. Embryonic developmental temperatures modulate thermal acclimation of performance curves in tadpoles of the frog Limnodynastes peronii.

    Directory of Open Access Journals (Sweden)

    Frank Seebacher

    Full Text Available Performance curves of physiological rates are not fixed, and determining the extent to which thermal performance curves can change in response to environmental signals is essential to understand the effect of climate variability on populations. The aim of this study was to determine whether and how temperatures experienced during early embryonic development affect thermal performance curves of later life history stages in the frog Limnodynastes peronii. We tested the hypotheses that a the embryonic environment affects mean trait values only; b temperature at which performance of tadpoles is maximal shifts with egg incubation temperatures so that performance is maximised at the incubation temperatures, and c incubation temperatures modulate the capacity for reversible acclimation in tadpoles. Growth rates were greater in warm (25°C compared to cold (15°C acclimated (6 weeks tadpoles regardless of egg developmental temperatures (15°C or 25°C, representing seasonal means. The breadth of the performance curve of burst locomotor performance (measured at 10, 15, 20, 25, and 30°C, representing annual range is greatest when egg developmental and acclimation temperatures coincide. The mode of the performance curves shifted with acclimation conditions and maximum performance was always at higher temperatures than acclimation conditions. Performance curves of glycolytic (lactate dehydrogenase activities and mitochondrial (citrate synthase and cytochrome c oxidase enzymes were modulated by interactions between egg incubation and acclimation temperatures. Lactate dehydrogenase activity paralleled patterns seen in burst locomotor performance, but oxygen consumption rates and mitochondrial enzyme activities did not mirror growth or locomotor performance. We show that embryonic developmental conditions can modulate performance curves of later life-history stages, thereby conferring flexibilty to respond to environmental conditions later in life.

  19. Thermal analysis of a prototype cryogenic polarization modulator for use in a space-borne CMB polarization experiment

    Science.gov (United States)

    Iida, T.; Sakurai, Y.; Matsumura, T.; Sugai, H.; Imada, H.; Kataza, H.; Ohsaki, H.; Hazumi, M.; Katayama, N.; Yamamoto, R.; Utsunomiya, S.; Terao, Y.

    2017-12-01

    We report a thermal analysis of a polarization modulator unit (PMU) for use in a space-borne cosmic microwave background (CMB) project. A measurement of the CMB polarization allows us to probe the physics of early universe, and that is the best method to test the cosmic inflation experimentally. One of the key instruments for this science is to use a halfwave plate (HWP) based polarization modulator. The HWP is required to rotate continuously at about 1 Hz below 10 K to minimize its own thermal emission to a detector system. The rotating HWP system at the cryogenic environment can be realized by using a superconducting magnetic bearing (SMB) without significant heat dissipation by mechanical friction. While the SMB achieves the smooth rotation due to the contactless bearing, an estimation of a levitating HWP temperature becomes a challenge. We manufactured a one-eighth scale prototype model of PMU and built a thermal model. We verified our thermal model with the experimental data. We forecasted the projected thermal performance of PMU for a full-scale model based on the thermal model. From this analysis, we discuss the design requirement toward constructing the full-scale model for use in a space environment such as a future CMB satellite mission, LiteBIRD.

  20. The measurements of thermal neutron flux distribution in a paraffin

    Indian Academy of Sciences (India)

    The term `thermal flux' implies a Maxwellian distribution of velocity and energy corresponding to the most probable velocity of 2200 ms-1 at 293.4 K. In order to measure the thermal neutron flux density, the foil activation method was used. Thermal neutron flux determination in paraffin phantom by counting the emitted rays of ...

  1. A review of test results on solar thermal power modules with dish-mounted Stirling and Brayton cycle engines

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-01-01

    This paper presents results of development tests of various solar thermal parabolic dish modules and assemblies that used dish-mounted Brayton or Stirling cycle engines for production of electric power. These tests indicate that early modules achieve net efficiencies up to 29 percent in converting sunlight to electricity, as delivered to the grid. Various equipment deficiencies were observed and a number of malfunctions occurred. The performance measurements, as well as the malfunctions and other test experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  2. A review of test results on solar thermal power modules with dish-mounted Stirling and Brayton cycle engines

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-11-01

    This paper presents results of development tests of various solar thermal parabolic dish modules and assemblies that used dish-mounted Brayton or Stirling cycle engines for production of electric power. These tests indicate that early modules achieve net efficiencies up to 29 percent in converting sunlight to electricity, as delivered to the grid. Various equipment deficiencies were observed and a number of malfunctions occurred. The performance measurements, as well as the malfunctions and other test experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  3. Measurements of Thermal Emittance for Cesium Telluride Photocathodes at PITZ

    CERN Document Server

    Miltchev, V; Grabosch, H J; Han, J H; Krasilnikov, M; Oppelt, A; Petrosian, B; Staykov, L; Stephan, F

    2005-01-01

    The thermal emittance determines the lower emittance limit and its measurement is of high importance to understand the ultimate injector performance. In this contribution we present results of thermal emittance measurements under rf operation conditions for various Cs2Te cathodes and different accelerating gradients. Measurements of thermal emittance scaling with the cathode laser spot size are presented and analysed. The significance of the Schottky effect in the emittance formation process is discussed.

  4. Development of whole core thermal-hydraulic analysis program ACT. 3. Coupling core module with primary heat transport system module

    International Nuclear Information System (INIS)

    Ohtaka, Masahiko; Ohshima, Hiroyuki

    1998-10-01

    A whole core thermal-hydraulic analysis program ACT is being developed for the purpose of evaluating detailed in-core thermal hydraulic phenomena of fast reactors including inter-wrapper flow under various reactor operation conditions. In this work, the core module as a main part of the ACT developed last year, which simulates thermal-hydraulics in the subassemblies and the inter-subassembly gaps, was coupled with an one dimensional plant system thermal-hydraulic analysis code LEDHER to simulate transients in the primary heat transport system and to give appropriate boundary conditions to the core model. The effective algorithm to couple these two calculation modules was developed, which required minimum modification of them. In order to couple these two calculation modules on the computing system, parallel computing technique using PVM (Parallel Virtual Machine) programming environment was applied. The code system was applied to analyze an out-of-pile sodium experiment simulating core with 7 subassemblies under transient condition for code verification. It was confirmed that the analytical results show a similar tendency of experimental results. (author)

  5. Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

    Science.gov (United States)

    Deng, Y. C.; Li, Q. P.; Wang, G. J.

    2017-11-01

    A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

  6. A four-probe thermal transport measurement method for nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li, E-mail: lishi@mail.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-04-15

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models.

  7. A four-probe thermal transport measurement method for nanostructures

    International Nuclear Information System (INIS)

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li

    2015-01-01

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models

  8. Thermal Diffusivity Measurement for Thermal Spray Coating Attached to Substrate Using Laser Flash Method

    Science.gov (United States)

    Akoshima, Megumi; Tanaka, Takashi; Endo, Satoshi; Baba, Tetsuya; Harada, Yoshio; Kojima, Yoshitaka; Kawasaki, Akira; Ono, Fumio

    2011-11-01

    Ceramic-based thermal barrier coatings are used as heat and wear shields of gas turbine blades. There is a strong need to evaluate the thermal conductivity of coating for thermal design and use. The thermal conductivity of a bulk material is obtained as the product of thermal diffusivity, specific heat capacity, and density above room temperature in many cases. Thermal diffusivity and thermal conductivity are unique for a given material because they are sensitive to the structure of the material. Therefore, it is important to measure them in each sample. However it is difficult to measure the thermal diffusivity and thermal conductivity of coatings because coatings are attached to substrates. In order to evaluate the thermal diffusivity of a coating attached to the substrate, we have examined the laser flash method with the multilayer model on the basis of the response function method. We carried out laser flash measurements in layered samples composed of a CoNiCrAlY bond coating and a 8YSZ top coating by thermal spraying on a Ni-based superalloy substrate. It was found that the procedure using laser flash method with the multilayer model is useful for the thermal diffusivity evaluation of a coating attached to a substrate.

  9. Development of additional module to neutron-physic and thermal-hydraulic computer codes for coolant acoustical characteristics calculation

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, K.N.; Bogomazov, D.N.; Poliakov, N. [Moscow Power Engineering Institute (Technical University), Moscow (Russian Federation)

    2007-07-01

    The new special module to neutron-physic and thermal-hydraulic computer codes for coolant acoustical characteristics calculation is worked out. The Russian computer code Rainbow has been selected for joint use with a developed module. This code system provides the possibility of EFOCP (Eigen Frequencies of Oscillations of the Coolant Pressure) calculations in any coolant acoustical elements of primary circuits of NPP. EFOCP values have been calculated for transient and for stationary operating. The calculated results for nominal operating were compared with results of measured EFOCP. For example, this comparison was provided for the system: 'pressurizer + surge line' of a WWER-1000 reactor. The calculated result 0.58 Hz practically coincides with the result of measurement (0.6 Hz). The EFOCP variations in transients are also shown. The presented results are intended to be useful for NPP vibration-acoustical certification. There are no serious difficulties for using this module with other computer codes.

  10. Development of additional module to neutron-physic and thermal-hydraulic computer codes for coolant acoustical characteristics calculation

    International Nuclear Information System (INIS)

    Proskuryakov, K.N.; Bogomazov, D.N.; Poliakov, N.

    2007-01-01

    The new special module to neutron-physic and thermal-hydraulic computer codes for coolant acoustical characteristics calculation is worked out. The Russian computer code Rainbow has been selected for joint use with a developed module. This code system provides the possibility of EFOCP (Eigen Frequencies of Oscillations of the Coolant Pressure) calculations in any coolant acoustical elements of primary circuits of NPP. EFOCP values have been calculated for transient and for stationary operating. The calculated results for nominal operating were compared with results of measured EFOCP. For example, this comparison was provided for the system: 'pressurizer + surge line' of a WWER-1000 reactor. The calculated result 0.58 Hz practically coincides with the result of measurement (0.6 Hz). The EFOCP variations in transients are also shown. The presented results are intended to be useful for NPP vibration-acoustical certification. There are no serious difficulties for using this module with other computer codes

  11. Microfabricated thermal modulator for comprehensive two-dimensional micro gas chromatography: design, thermal modeling, and preliminary testing.

    Science.gov (United States)

    Kim, Sung-Jin; Reidy, Shaelah M; Block, Bruce P; Wise, Kensall D; Zellers, Edward T; Kurabayashi, Katsuo

    2010-07-07

    In comprehensive two-dimensional gas chromatography (GC x GC), a modulator is placed at the juncture between two separation columns to focus and re-inject eluting mixture components, thereby enhancing the resolution and the selectivity of analytes. As part of an effort to develop a microGC x microGC prototype, in this report we present the design, fabrication, thermal operation, and initial testing of a two-stage microscale thermal modulator (microTM). The microTM contains two sequential serpentine Pyrex-on-Si microchannels (stages) that cryogenically trap analytes eluting from the first-dimension column and thermally inject them into the second-dimension column in a rapid, programmable manner. For each modulation cycle (typically 5 s for cooling with refrigeration work of 200 J and 100 ms for heating at 10 W), the microTM is kept approximately at -50 degrees C by a solid-state thermoelectric cooling unit placed within a few tens of micrometres of the device, and heated to 250 degrees C at 2800 degrees C s(-1) by integrated resistive microheaters and then cooled back to -50 degrees C at 250 degrees C s(-1). Thermal crosstalk between the two stages is less than 9%. A lumped heat transfer model is used to analyze the device design with respect to the rates of heating and cooling, power dissipation, and inter-stage thermal crosstalk as a function of Pyrex-membrane thickness, air-gap depth, and stage separation distance. Experimental results are in agreement with trends predicted by the model. Preliminary tests using a conventional capillary column interfaced to the microTM demonstrate the capability for enhanced sensitivity and resolution as well as the modulation of a mixture of alkanes.

  12. Development of core thermal-hydraulics module for intelligent reactor design system (IRDS)

    International Nuclear Information System (INIS)

    Kugo, Teruhiko; Nakagawa, Masayuki; Fujii, Sadao.

    1994-08-01

    We have developed an innovative reactor core thermal-hydraulics module where a designer can easily and efficiently evaluate his design concept of a new type reactor in the thermal-hydraulics field. The main purpose of this module is to decide a feasible range of basic design parameters of a reactor core in a conceptual design stage of a new type reactor. The module is to be implemented in Intelligent Reactor Design System (IRDS). The module has the following characteristics; 1) to deal with several reactor types, 2) four thermal hydraulics and fuel behavior analysis codes are installed to treat different type of reactors and design detail, 3) to follow flexibly modification of a reactor concept, 4) to provide analysis results in an understandable way so that a designer can easily evaluate feasibility of his concept, and so on. The module runs on an engineering workstation (EWS) and has a user-friendly man-machine interface on a pre- and post-processing. And it is equipped with a function to search a feasible range called as Design Window, for two design parameters by artificial intelligence (AI) technique and knowledge engineering. In this report, structure, guidance for users of an usage of the module and instruction of input data for analysis modules are presented. (author)

  13. Thermal conductivity measurements in unsaturated hydrate-bearing sediments

    Science.gov (United States)

    Dai, Sheng; Cha, Jong-Ho; Rosenbaum, Eilis J.; Zhang, Wu; Seol, Yongkoo

    2015-08-01

    Current database on the thermal properties of hydrate-bearing sediments remains limited and has not been able to capture their consequential changes during gas production where vigorous phase changes occur in this unsaturated system. This study uses the transient plane source (TPS) technique to measure the thermal conductivity of methane hydrate-bearing sediments with various hydrate/water/gas saturations. We propose a simplified method to obtain thermal properties from single-sided TPS signatures. Results reveal that both volume fraction and distribution of the pore constituents govern the thermal conductivity of unsaturated specimens. Thermal conductivity hysteresis is observed due to water redistribution and fabric change caused by hydrate formation and dissociation. Measured thermal conductivity increases evidently when hydrate saturation Sh > 30-40%, shifting upward from the geometric mean model prediction to a Pythagorean mixing model. These observations envisage a significant drop in sediment thermal conductivity when residual hydrate/water saturation falls below ~40%, hindering further gas production.

  14. Plasma flow velocity measurements using a modulated Michelson interferometer

    International Nuclear Information System (INIS)

    Howard, J.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (orig.)

  15. Numerical Investigation of the Thermal Management Performance of MEPCM Modules for PV Applications

    Directory of Open Access Journals (Sweden)

    Chao-Yang Huang

    2013-08-01

    Full Text Available The efficiency of photovoltaic modules decreases as the cell temperature increases. It is necessary to have an adequate thermal management mechanism for a photovoltaic module, especially when combined with a building construction system. This study aims to investigate via computational fluid dynamics simulations the heat transfer characteristics and thermal management performance of microencapsulated phase change material modules for photovoltaic applications under temporal variations of daily solar irradiation. The results show that the aspect ratio of the microencapsulated phase change material layer has significant effects on the heat transfer characteristics and the overall thermal performance of the two cases examined with different melting points (26 °C and 34 °C are approximately the same.

  16. Thermal Conductivity Measurement of Anisotropic Biological Tissue In Vitro

    Science.gov (United States)

    Yue, Kai; Cheng, Liang; Yang, Lina; Jin, Bitao; Zhang, Xinxin

    2017-06-01

    The accurate determination of the thermal conductivity of biological tissues has implications on the success of cryosurgical/hyperthermia treatments. In light of the evident anisotropy in some biological tissues, a new modified stepwise transient method was proposed to simultaneously measure the transverse and longitudinal thermal conductivities of anisotropic biological tissues. The physical and mathematical models were established, and the analytical solution was derived. Sensitivity analysis and experimental simulation were performed to determine the feasibility and measurement accuracy of simultaneously measuring the transverse and longitudinal thermal conductivities. The experimental system was set up, and its measurement accuracy was verified by measuring the thermal conductivity of a reference standard material. The thermal conductivities of the pork tenderloin and bovine muscles were measured using the traditional 1D and proposed methods, respectively, at different temperatures. Results indicate that the thermal conductivities of the bovine muscle are lower than those of the pork tenderloin muscle, whereas the bovine muscle was determined to exhibit stronger anisotropy than the pork tenderloin muscle. Moreover, the longitudinal thermal conductivity is larger than the transverse thermal conductivity for the two tissues and all thermal conductivities increase with the increase in temperature. Compared with the traditional 1D method, results obtained by the proposed method are slightly higher although the relative deviation is below 5 %.

  17. Design and Construction of a Thermal Contact Resistance and Thermal Conductivity Measurement System

    Science.gov (United States)

    2015-09-01

    thank my Mom, Dad , Allison, Jessica, and father-in-law, Tom, for always being there to listen and encourage me. xxiv THIS PAGE INTENTIONALLY...thermal conductivity is temperature measurement inaccuracies. A probe constructed of a poor thermally conductive material when inserted into a hot...interface- resistance-measurement-using-a-transient-method/ [26] H. Fukushima, L. T. Drzal, B. P. Rook and M. J. Rich , “Thermal conductivity of exfoliated

  18. Thermal-hydraulic interfacing code modules for CANDU reactors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.S.; Gold, M.; Sills, H. [Ontario Hydro Nuclear, Toronto (Canada)] [and others

    1997-07-01

    The approach for CANDU reactor safety analysis in Ontario Hydro Nuclear (OHN) and Atomic Energy of Canada Limited (AECL) is presented. Reflecting the unique characteristics of CANDU reactors, the procedure of coupling the thermal-hydraulics, reactor physics and fuel channel/element codes in the safety analysis is described. The experience generated in the Canadian nuclear industry may be useful to other types of reactors in the areas of reactor safety analysis.

  19. Thermal-hydraulic interfacing code modules for CANDU reactors

    International Nuclear Information System (INIS)

    Liu, W.S.; Gold, M.; Sills, H.

    1997-01-01

    The approach for CANDU reactor safety analysis in Ontario Hydro Nuclear (OHN) and Atomic Energy of Canada Limited (AECL) is presented. Reflecting the unique characteristics of CANDU reactors, the procedure of coupling the thermal-hydraulics, reactor physics and fuel channel/element codes in the safety analysis is described. The experience generated in the Canadian nuclear industry may be useful to other types of reactors in the areas of reactor safety analysis

  20. Thermal Simulation of Switching Pulses in an Insulated Gate Bipolar Transistor (IGBT) Power Module

    Science.gov (United States)

    2015-02-01

    executed with SolidWorks Flow Simulation , a computational fluid-dynamics code. The graph in Fig. 2 shows the timing and amplitudes of power pulses...defined a convective flow of air perpendicular to the bottom surface of the mounting plate, with a velocity of 10 ft/s. The thermal simulations were...Thermal Simulation of Switching Pulses in an Insulated Gate Bipolar Transistor (IGBT) Power Module by Gregory K Ovrebo ARL-TR-7210

  1. Coherent gradient sensing method for measuring thermal stress field of thermal barrier coating structures

    Directory of Open Access Journals (Sweden)

    Kang Ma

    2017-01-01

    Full Text Available Coherent gradient sensing (CGS method can be used to measure the slope of a reflective surface, and has the merits of full-field, non-contact, and real-time measurement. In this study, the thermal stress field of thermal barrier coating (TBC structures is measured by CGS method. Two kinds of powders were sprayed onto Ni-based alloy using a plasma spraying method to obtain two groups of film–substrate specimens. The specimens were then heated with an oxy-acetylene flame. The resulting thermal mismatch between the film and substrate led to out-of-plane deformation of the specimen. The deformation was measured by the reflective CGS method and the thermal stress field of the structure was obtained through calibration with the help of finite element analysis. Both the experiment and numerical results showed that the thermal stress field of TBC structures can be successfully measured by CGS method.

  2. Measurement of mismatch loss in CPV modul

    Science.gov (United States)

    Liu, Mingguo; Kinsey, Geoffrey S.; Bagienski, Will; Nayak, Adi; Garboushian, Vahan

    2012-10-01

    A setup capable of simultaneously measuring I-V curves of a full string and its individual cells has been developed. This setup enables us to measure mismatch loss from individual cells in concert with various string combinations under varying field conditions. Mismatch loss from cells to plates at different off-track angles and mismatch from plates to strings in Amonix system during normal operation have been investigated.

  3. PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING

    International Nuclear Information System (INIS)

    LUO, Y.; PILAT, F.; ROSER, T.

    2004-01-01

    The measurement of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of different skew quadrupole families the two eigentunes are precisely measured with the phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation directions are determined. The residual linear coupling could be corrected according to the measurement. An analytical solution for skew quadrupole modulation based on Hamiltonian perturbation approximation is given, and simulation code using smooth accelerator model is also developed. Some issues concerning the practical applications of this technique are discussed

  4. Wide-range measurement of thermal effusivity using molybdenum thin film with low thermal conductivity for thermal microscopes

    Science.gov (United States)

    Miyake, Shugo; Matsui, Genzou; Ohta, Hiromichi; Hatori, Kimihito; Taguchi, Kohei; Yamamoto, Suguru

    2017-07-01

    Thermal microscopes are a useful technology to investigate the spatial distribution of the thermal transport properties of various materials. However, for high thermal effusivity materials, the estimated values of thermophysical parameters based on the conventional 1D heat flow model are known to be higher than the values of materials in the literature. Here, we present a new procedure to solve the problem which calculates the theoretical temperature response with the 3D heat flow and measures reference materials which involve known values of thermal effusivity and heat capacity. In general, a complicated numerical iterative method and many thermophysical parameters are required for the calculation in the 3D heat flow model. Here, we devised a simple procedure by using a molybdenum (Mo) thin film with low thermal conductivity on the sample surface, enabling us to measure over a wide thermal effusivity range for various materials.

  5. Method and apparatus for implementing material thermal property measurement by flash thermal imaging

    Science.gov (United States)

    Sun, Jiangang

    2017-11-14

    A method and apparatus are provided for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property. The test apparatus includes an infrared camera, a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data, a flash lamp providing an input of heat onto the surface of a two-layer sample with an enhanced optical filter covering the flash lamp attenuating an entire infrared wavelength range with a series of thermal images is taken of the surface of the two-layer sample.

  6. Characteristics of Laser Flash Technique for Thermal Diffusivity Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Park, D. G.; Kim, H. M.; Hong, G. P

    2008-08-15

    In relation to selection of thermal conductivity measurement technology, various thermal conductivity measurement technique are investigated for characteristics of each technique and it's measurable range. For the related laser flash techniques, various technical characteristics are reviewed and discussed. Especially, Parker adiabatic model are reviewed because of importance for basic theory of the thermal diffusivity determination. Finite pulse time effect, heat loss effect and non-uniform heating effect, which are main technical factors for laser flash technique, are considered. Finally, characteristics of constituent elements for laser flash measurement system are reviewed and investigated in detail.

  7. Development of Light Powered Sensor Networks for Thermal Comfort Measurement

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-10-01

    Full Text Available Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

  8. Numerical model analysis of thermal performance for a dye-sensitized solar cell module

    International Nuclear Information System (INIS)

    Chen, Shuanghong; Huang, Yang; Weng, Jian; Fan, Xiaqin; Mo, Lie; Pan, Bin; Dai, Songyuan

    2013-01-01

    Temperature is one of the major factors that influence a dye-sensitized solar cell's (DSC's) photovoltaic efficiency. Temperature control is very important when solar cell modules are designed. In the present paper, a numerical model of a DSC module is built for the simulation of the solar cell's temperature. In this model, energy balance and three methods of heat transfer (conduction, convection, and radiation) are taken into account, and the simulation results are consistent with the experimental results. The influence of wind speeds and interfacial thermal resistance on the temperature inside the DSC modules is discussed in detail based on theoretical analysis. (paper)

  9. Thermal and electrical energy yield analysis of a directly water cooled photovoltaic module

    Directory of Open Access Journals (Sweden)

    Mtunzi Busiso

    2016-01-01

    Full Text Available Electrical energy of photovoltaic modules drops by 0.5% for each degree increase in temperature. Direct water cooling of photovoltaic modules was found to give improved electrical and thermal yield. A prototype was put in place to analyse the field data for a period of a year. The results showed an initial high performance ratio and electrical power output. The monthly energy saving efficiency of the directly water cooled module was found to be approximately 61%. The solar utilisation of the naturally cooled photovoltaic module was found to be 8.79% and for the directly water cooled module its solar utilisation was 47.93%. Implementation of such systems on households may reduce the load from the utility company, bring about huge savings on electricity bills and help in reducing carbon emissions.

  10. Microscopic cross-section measurements by thermal neutron activation

    International Nuclear Information System (INIS)

    Avila L, J.

    1987-08-01

    Microscopic cross sections measured by thermal neutron activation using RP-0 reactor at the Peruvian Nuclear Energy Institute. The method consists in measuring microscopic cross section ratios through activated samples, requiring being corrected in thermal and epithermal energetic range by Westcott formalism. Furthermore, the comptage ratios measured for each photopeak to its decay fraction should be normalized from interrelation between both processes above, activation microscopic cross sections are obtained

  11. New methodology of measurement the unsteady thermal cooling of objects

    Science.gov (United States)

    Winczek, Jerzy

    2018-04-01

    The problems of measurements of unsteady thermal turbulent flow affect a many of domains, such as heat energy, manufacturing technologies, and many others. The subject of the study is focused on the analysis of current state of the problem, overview of the design solutions and methods to measure non-stationary thermal phenomena, presentation, and choice of adequate design of the cylinder, development of the method to measure and calculate basic values that characterize the process of heat exchange on the model surface.

  12. Electro-thermal modeling of high power IGBT module short-circuits with experimental validation

    DEFF Research Database (Denmark)

    Wu, Rui; Iannuzzo, Francesco; Wang, Huai

    2015-01-01

    A novel Insulated Gate Bipolar Transistor (IGBT) electro-thermal modeling approach involving PSpice and ANSYS/Icepak with both high accuracy and simulation speed has been presented to study short-circuit of a 1.7 kV/1 kA commercial IGBT module. The approach successfully predicts the current...

  13. System to Measure Thermal Conductivity and Seebeck Coefficient for Thermoelectrics

    Science.gov (United States)

    Kim, Hyun-Jung; Skuza, Jonathan R.; Park, Yeonjoon; King, Glen C.; Choi, Sang H.; Nagavalli, Anita

    2012-01-01

    The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at elevated temperatures. This has led to the implementation of nonstandardized practices that have further complicated the confirmation of reported high ZT materials. The major objective of the procedure described is for the simultaneous measurement of the Seebeck coefficient and thermal diffusivity within a given temperature range. These thermoelectric measurements must be precise, accurate, and reproducible to ensure meaningful interlaboratory comparison of data. The custom-built thermal characterization system described in this NASA-TM is specifically designed to measure the inplane thermal diffusivity, and the Seebeck coefficient for materials in the ranging from 73 K through 373 K.

  14. Measurements of thermal diffusivity, specific heat capacity and thermal conductivity with LFA 447 apparatus

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub; Heiselberg, Per

    The LFA 447 can be successfully used for measurements of thermal diffusivity, specific heat and thermal conductivity of various samples. It is especially useful when determining the properties of materials on a very small scale. The matrix measurement mode allows for determining the local...... that the heat losses from both samples during the measurement are similar. Finally, the leveling of the samples is very important. Very small discrepancies can cause a massive error in the derivation of specific heat capacity and, as a result, thermal conductivity....

  15. Engineering aspects of a thermal control subsystem for the 25 kW power module

    Science.gov (United States)

    Schroeder, P. E.

    1979-01-01

    The paper presents the key trade study results, analysis results, and the recommended thermal control approach for the 25 kW power module defined by NASA. Power conversion inefficiencies and component heat dissipation results in a minimum heat rejection requirement of 9 kW to maintain the power module equipment at desired temperature levels. Additionally, some cooling capacity should be provided for user payloads in the sortie and free-flying modes. The baseline thermal control subsystem includes a dual-loop-pumped Freon-21 coolant with the heat rejected from deployable existing orbiter radiators. Thermal analysis included an assessment of spacecraft orientations, radiator shapes and locations, and comparison of hybrid heat pipe and all liquid panels.

  16. Measurement of through-thickness thermal diffusivity of thermoplastics using thermal wave method

    Science.gov (United States)

    Singh, R.; Mellinger, A.

    2015-04-01

    Thermo-physical properties, such as thermal conductivity, thermal diffusivity and specific heat are important quantities that are needed to interpret and characterize thermoplastic materials. Such characterization is necessary for many applications, ranging from aerospace engineering to food packaging, electrical and electronic industry and medical science. In this work, the thermal diffusivity of commercially available polymeric films is measured in the thickness direction at room temperature using thermal wave method. The results obtained with this method are in good agreement with theoretical and experimental values.

  17. Use of the Long Duration Exposure Facility's thermal measurement system for the verification of thermal models

    Science.gov (United States)

    Berrios, William M.

    1992-01-01

    The Long Duration Exposure Facility (LDEF) postflight thermal model predicted temperatures were matched to flight temperature data recorded by the Thermal Measurement System (THERM), LDEF experiment P0003. Flight temperatures, recorded at intervals of approximately 112 minutes for the first 390 days of LDEF's 2105 day mission were compared with predictions using the thermal mathematical model (TMM). This model was unverified prior to flight. The postflight analysis has reduced the thermal model uncertainty at the temperature sensor locations from +/- 40 F to +/- 18 F. The improved temperature predictions will be used by the LDEF's principal investigators to calculate improved flight temperatures experienced by 57 experiments located on 86 trays of the facility.

  18. Measurement and model on thermal properties of sintered diamond composites

    International Nuclear Information System (INIS)

    Moussa, Tala; Garnier, Bertrand; Peerhossaini, Hassan

    2013-01-01

    Highlights: ► Thermal properties of sintered diamond used for grinding is studied. ► Flash method with infrared temperature measurement is used to investigate. ► Thermal conductivity increases with the amount of diamond. ► It is very sensitive to binder conductivity. ► Results agree with models assuming imperfect contact between matrix and particles. - Abstract: A prelude to the thermal management of grinding processes is measurement of the thermal properties of working materials. Indeed, tool materials must be chosen not only for their mechanical properties (abrasion performance, lifetime…) but also for thermal concerns (thermal conductivity) for efficient cooling that avoids excessive temperatures in the tool and workpiece. Sintered diamond is currently used for grinding tools since it yields higher performances and longer lifetimes than conventional materials (mineral or silicon carbide abrasives), but its thermal properties are not yet well known. Here the thermal conductivity, heat capacity and density of sintered diamond are measured as functions of the diamond content in composites and for two types of metallic binders: hard tungsten-based and soft cobalt-based binders. The measurement technique for thermal conductivity is derived from the flash method. After pulse heating, the temperature of the rear of the sample is measured with a noncontact method (infrared camera). A parameter estimation method associated with a three-layer nonstationary thermal model is used to obtain sample thermal conductivity, heat transfer coefficient and absorbed energy. With the hard metallic binder, the thermal conductivity of sintered diamond increased by up to 64% for a diamond content increasing from 0 to 25%. The increase is much less for the soft binder: 35% for diamond volumes up to 25%. In addition, experimental data were found that were far below the value predicted by conventional analytical models for effective thermal conductivity. A possible explanation

  19. Calculations of flexibility module in measurements instruments

    Science.gov (United States)

    Wróbel, A.; Płaczek, M.; Baier, A.

    2017-08-01

    Piezoelectricity has found a lot of applications since it were discovered in 1880 by Pierre and Jacques Curie. There are many applications of the direct piezoelectric effect - the production of an electric potential when stress is applied to the piezoelectric material, as well as the reverse piezoelectric effect - the production of strain when an electric field is applied. This work presents a mathematical model of a new model of vibration sensor. The principle of operation of currently used sensors is based on the idea: changes in thickness of the piezoelectric plates cause the vibration of the mechanical element, so-called “fork”. If the “forks” are not buried by the material deformation of the full tiles broadcasting is transmitted to receiver piezoelectric plate. As a result of vibration of receiver plates the cladding is formed on the potential difference proportional to the force. The value of this voltage is processed by an electronic circuit. In the case of backfilling “forks” the electric signal is lower. At the same time is not generated the potential for cladding tiles. Such construction have a lot of drawbacks, for example: need to use several piezoelectric plates, with the increase in number of components is increased failure of sensors, sensors have now produced two forks resonance, using these sensors in moist materials is often the case that the material remains between the forks and at the same time causes a measurement error. Mentioned disadvantages do not appear in the new proposed sensor design. The Galerkin method of the analysis of considered systems will be presented started from development of the mathematical model, to determine the graphs of flexibility and confirm two methods: exact and approximate. Analyzed beam is a part of the vibration level sensor and the results will be used to identify the electrical parameters of the generator. Designing of technical systems containing piezoelectric transducers is a complex process

  20. Apparatus for measuring low thermal fluxes

    International Nuclear Information System (INIS)

    Aranovitch, R.; Warnery, M.

    1972-01-01

    Device for the measurement of slight wall heat fluxes, made up of a metallic contact plate combined with a shaft; temperature measurement elements are spaced along the shaft which is kept at a cold adjustable reference temperature lower than that of the walls; heat insulation is provided for the exposed part of the plate and for the shaft [fr

  1. Influence of coil current modulation on polycrystalline diamond film deposition by irradiation of Ar/CH4/H2 inductively coupled thermal plasmas

    Science.gov (United States)

    Betsuin, Toshiki; Tanaka, Yasunori; Arai, T.; Uesugi, Y.; Ishijima, T.

    2018-03-01

    This paper describes the application of an Ar/CH4/H2 inductively coupled thermal plasma with and without coil current modulation to synthesise diamond films. Induction thermal plasma with coil current modulation is referred to as modulated induction thermal plasma (M-ITP), while that without modulation is referred to as non-modulated ITP (NM-ITP). First, spectroscopic observations of NM-ITP and M-ITP with different modulation waveforms were made to estimate the composition in flux from the thermal plasma by measuring the time evolution in the spectral intensity from the species. Secondly, we studied polycrystalline diamond film deposition tests on a Si substrate, and we studied monocrystalline diamond film growth tests using the irradiation of NM-ITP and M-ITP. From these tests, diamond nucleation effects by M-ITP were found. Finally, following the irradiation results, we attempted to use a time-series irradiation of M-ITP and NM-ITP for polycrystalline diamond film deposition on a Si substrate. The results indicated that numerous larger diamond particles were deposited with a high population density on the Si substrate by time-series irradiation.

  2. Measuring modulated luminescence using non-modulated stimulation: Ramping the sample period

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Andersen, C.E.

    2003-01-01

    . Directly analogous results to LM-OSL can, however, be achieved with non-modulated excitation sources, by ramping the sample period (RSP) of luminescence detection. RSP-OSL has the distinct advantage over LM-OSL in that, since the excitation remains at full power, data accumulation times (that can...... be considerable) can be reduced by typically 50%. RSP methods are universally applicable and can be employed, for example, where the excitation source is constant heat, rather than light: here, iso-thermal decay of phosphorescence becomes recorded as a sequence of peaks, corresponding to de-trapping of charge...

  3. Comparison of Thermal Properties Measured by Different Methods

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, Jan [Geo Innova AB, Linkoeping (Sweden); Kukkonen, Ilmo [Geological Survey of Finland, Helsinki (Finland); Haelldahl, Lars [Hot Disk AB, Uppsala (Sweden)

    2003-04-01

    A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

  4. Comparison of Thermal Properties Measured by Different Methods

    International Nuclear Information System (INIS)

    Sundberg, Jan; Kukkonen, Ilmo; Haelldahl, Lars

    2003-04-01

    A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

  5. Implementation of CFD module in the KORSAR thermal-hydraulic system code

    Energy Technology Data Exchange (ETDEWEB)

    Yudov, Yury V.; Danilov, Ilia G.; Chepilko, Stepan S. [Alexandrov Research Inst. of Technology (NITI), Sosnovy Bor (Russian Federation)

    2015-09-15

    The Russian KORSAR/GP (hereinafter KORSAR) computer code was developed by a joint team from Alexandrov NITI and OKB ''Gidropress'' for VVER safety analysis and certified by the Rostechnadzor of Russia in 2009. The code functionality is based on a 1D two-fluid model for calculation of two-phase flows. A 3D CFD module in the KORSAR computer code is being developed by Alexandrov NITI for representing 3D effects in the downcomer and lower plenum during asymmetrical loop operation. The CFD module uses Cartesian grid method with cut cell approach. The paper presents a numerical algorithm for coupling 1D and 3D thermal- hydraulic modules in the KORSAR code. The combined pressure field is calculated by the multigrid method. The performance efficiency of the algorithm for coupling 1D and 3D modules was demonstrated by solving the benchmark problem of mixing cold and hot flows in a T-junction.

  6. A Novel 3D Thermal Impedance Model for High Power Modules Considering Multi-layer Thermal Coupling and Different Heating/Cooling Conditions

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2015-01-01

    accurate temperature estimation either vertically or horizontally inside the power devices is still hard to identify. This paper investigates the thermal behavior of high power module in various operating conditions by means of Finite Element Method (FEM). A novel 3D thermal impedance network considering......Thermal management of power electronic devices is essential for reliable performance especially at high power levels. One of the most important activities in the thermal management and reliability improvement is acquiring the temperature information in critical points of the power module. However...

  7. Thermal conductivity measurements at cryogenic temperatures at LASA

    International Nuclear Information System (INIS)

    Broggi, F.; Pedrini, D.; Rossi, L.

    1995-08-01

    Here the improvement realised to have better control of the reference junction temperature and measurements carried out on Nb 3 Sn cut out from 2 different coils (named LASA3 and LASA5), showing the difference between the longitudinal and the transverse thermal conductivity, is described. Two different methods of data analysis are presented, the DAM (derivative approximated method) and the TCI (thermal conductivity integral. The data analysis for the tungsten and the LASA5 coil has been done according to the two methods showing that the TCI method with polynomial functions is not adequate to describe the thermal conductivity. Only a polynomial fit based on the TCI method but limited at a lower order than the nominal, when the data are well distributed along the range of measurements, can describe reasonably the thermal conductivity dependence with the temperature. Finally the measurements on a rod of BSCCO 2212 high T c superconductor are presented

  8. Cryogenic Thermal Conductivity Measurements on Candidate Materials for Space Missions

    Science.gov (United States)

    Tuttle, JIm; Canavan, Ed; Jahromi, Amir

    2017-01-01

    Spacecraft and instruments on space missions are built using a wide variety of carefully-chosen materials. In addition to having mechanical properties appropriate for surviving the launch environment, these materials generally must have thermal conductivity values which meet specific requirements in their operating temperature ranges. Space missions commonly propose to include materials for which the thermal conductivity is not well known at cryogenic temperatures. We developed a test facility in 2004 at NASAs Goddard Space Flight Center to measure material thermal conductivity at temperatures between 4 and 300 Kelvin, and we have characterized many candidate materials since then. The measurement technique is not extremely complex, but proper care to details of the setup, data acquisition and data reduction is necessary for high precision and accuracy. We describe the thermal conductivity measurement process and present results for several materials.

  9. A 3D Lumped Thermal Network Model for Long-term Load Profiles Analysis in High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Ghimire, Pramod

    2016-01-01

    )-based simulation is another method which is often used to analyze the steady-state thermal distribution of IGBT modules, but it is not possible to be used for long-term analysis of load profiles of power converter, which is needed for reliability assessments and better thermal design. This paper proposes a novel...... enables both accurate and fast temperature estimation of high power IGBT modules in the real loading conditions of the converter; meanwhile the critical details of the thermal dynamics and thermal distribution are also maintained. The proposed thermal model is verified by both FEM simulation......The conventional RC lumped thermal networks are widely used to estimate the temperature of power devices, but they are lack of accuracy in addressing detailed thermal behaviors/couplings in different locations and layers of the high power IGBT modules. On the other hand, Finite Element (FE...

  10. Mathematical model for solar drying of potato cylinders with thermal conductivity radially modulated

    Science.gov (United States)

    Trujillo Arredondo, Mariana

    2014-05-01

    A mathematical model for drying potato cylinders using solar radiation is proposed and solved analytically. The model incorporates the energy balance for the heat capacity of the potato, the radiation heat transfer from the potato toward the drying chamber and the solar radiation absorbed by the potato during the drying process. Potato cylinders are assumed to exhibit a thermal conductivity which is radially modulated. The method of the Laplace transform, with integral Bromwich and residue theorem will be applied and the analytic solutions for the temperature profiles in the potato cylinder will be derived in the form of an infinite series of Bessel functions, when the thermal conductivity is constant; and in the form of an infinite series of Heun functions, when the thermal conductivity has a linear radial modulation. All computations are performed using computer algebra, specifically Maple. It is expected that the analytical results obtained will be useful in food engineering and industry. Our results suggest some lines for future investigations such as the adoption of more general forms of radial modulation for the thermal conductivity of potato cylinders; and possible applications of other computer algebra software such as Maxima and Mathematica.

  11. Thermal conductivity of Al–Cu–Mg–Si alloys: Experimental measurement and CALPHAD modeling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Du, Yong, E-mail: yong-du@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Liu, Shuhong; Liu, Yuling [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Sundman, Bo. [INSTN, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2016-07-10

    Highlights: • The thermal conductivities of Al–x wt% Cu (x = 1, 3, 5, 15 and 30) and Al–y wt% Si (y = 2, 12.5 and 20) alloys were determined. • The reported thermal conductivities of Al–Cu–Mg–Si system were critically reviewed. • The CALPHAD approach was applied for the modeling of thermal conductivity. • The applicability of CALPHAD technique in the modeling of thermal conductivity was discussed. - Abstract: In the present work, the thermal conductivities and microstructure of Al–x wt% Cu (x = 1, 3, 5, 15 and 30) and Al–y wt% Si (y = 2, 12.5 and 20) alloys were investigated by using laser-flash method, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Besides, a CALPHAD (CALculation of PHAse Diagram) approach to evaluate the thermal conductivity of Al–Cu–Mg–Si system was performed. The numerical models for the thermal conductivity of pure elements and stoichiometric phases were described as polynomials, and the coefficients were optimized via PARROT module of Thermal-Calc software applied to the experimental data. The thermal conductivity of (Al)-based solid solutions was described by using Redlich–Kister interaction parameters. For alloys in two-phase region, the interface scattering parameter was proposed in the modeling to describe the impediment of interfaces on the heat transfer. Finally, a set of self-consistent parameters for the description of thermal conductivity in Al–Cu–Mg–Si system was obtained, and comprehensive comparisons between the calculated and measured thermal conductivities show that the experimental information is satisfactorily accounted for by the present modeling.

  12. Thermomechanical fields measurement for fatigue investigation under cyclic thermal shocks

    International Nuclear Information System (INIS)

    Charbal, Ali

    2017-01-01

    Thermal fatigue occurs in nuclear power plant pipes. The temperature variations are due to the turbulent mixing of fluids that have different temperatures. Many experimental setups have been designed but the measured temperatures have only been punctual and out of the zone of interest (e.g., via thermocouples). The equivalent strain variation in the crack initiation region is calculated with numerical thermomechanical simulations. In many cases, the comparisons between numerical and experimental results have shown that the crack initiation predictions in thermal fatigue are non-conservative. a new testing setup is proposed where thermal shocks are applied with a pulsed laser beam while the thermal and kinematic fields on the specimen surface are measured with infrared (IR) and visible cameras, respectively. Experimental testings are performed and different measurement techniques for temperature and kinematic fields are used. IR camera and pyrometers allow to measure the temperature variations in the zone impacted by the laser beam. To estimate the absolute temperature, the surface emissivities at the respective wavelengths are determined by different methods. The absolute temperature field is then used to apply the actual thermal loading in a decoupled FE model after an identification process of the parameters of the laser beam. Once the thermal loading is generated based upon the experimental data, the stress and strain fields can be computed in the region of interest with an elastoplastic law.The experimental strain variations calculated from the DIC measurements are compared with the predictions obtained with the FE simulation. (author) [fr

  13. A transient divided-bar method for simultaneous measurements of thermal conductivity and thermal diffusivity

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, Søren Bom; Balling, Niels

    2016-01-01

    and volumetric heat capacity, and thereby also thermal diffusivity, are measured simultaneously. As the density of samples is easily determined independently, specific heat capacity may also be determined. Finite element formulation provides a flexible forward solution for heat transfer across the bar...... and thermal properties are estimated by inverse Monte Carlo modelling. This methodology enables a proper quantification of experimental uncertainties on measured thermal properties. The developed methodology was applied to laboratory measurements of various materials, including a standard ceramic material......-3 %, and for diffusivity uncertainty may be reduced to about 3-5 %. The main uncertainty originates from the presence of thermal contact resistance associated with the internal interfaces of the bar. They are not resolved during inversion, and it is highly important that they are minimized by careful sample preparation....

  14. Solid Layer Thermal-conductivity Measurement Techniques

    Science.gov (United States)

    1994-03-01

    deposited on the sample, and the absorption of laser radiation. Temperature-measurement tools include thermocouples, infrared (IR) pyrometers , and...A, Nishimura H, and Sawada T (1990), Laser-Induc~d Surface Acoustic Waves and Photothc:rmal Surfitce Gratings Generated by Crossing Two Pulsed

  15. A new method of measuring the thermal flow

    Directory of Open Access Journals (Sweden)

    Grexová Slávka

    2001-03-01

    Full Text Available The subject of this article is the measurement of thermal flow under laboratory conditions. We can define thermal flow as the amount of heat transmitted through the surface of rock over a certain period of time.According to the Atlas of Geothermal Energy the thermal flow ranges from 40 to 120 mW/m2; it is not possible to measure directly on the surface of the rock. The conventional method of measurement is the use of “separation bar” thermic conduction measurement system or to measure the temperature of the rock in two different places at selected underground depth intervals.The method of measurement suggested by us combines these two techniques. The measurement is based on a sample of processed store from the Slovak Academy of Science. This sample represents the rock massiv:The complex model includes:- a heating system to imitate the thermal flow,- an isolation box to maintain stable conditions,- temperature stabilizing components (thermostat, bulbs, electric conductors,- a heat accumulator including a temperature sensor.A special computer program to measure the thermal flow was created using the Borland Delphi 3.0 programming language. The role of the program is to process extensive data quickly. The results of the measured temperatures and modelled thermal flow are displayed graphically in this article. As seen from the graph, the course of measurement thermal flow is linear. In our geographical location this value is cca 120 m W.m-2. This value proves, that at the projection physical model we are approximating to the reality in areas of sensitive elements. Another fact is that Joule heat which rose into a heater system of transformer straps under muster would thermal flow 2,25 W.m-2. From the present results that by follow the sensitivity measurement scanners it is needed to measure a minimum threefold during a longer time or to improve the sensitivity measurement chains.These measurements and analyses are not sufficient to make a final

  16. Color of hot soup modulates postprandial satiety, thermal sensation, and body temperature in young women.

    Science.gov (United States)

    Suzuki, Maki; Kimura, Rie; Kido, Yasue; Inoue, Tomoko; Moritani, Toshio; Nagai, Narumi

    2017-07-01

    The color of food is known to modulate not only consumers' motivation to eat, but also thermal perception. Here we investigated whether the colors of hot soup can influence thermal sensations and body temperature, in addition to the food acceptability and appetite. Twelve young female participants consumed commercial white potage soup, modified to yellow or blue by adding food dyes, at 9 a.m. on 3 separated days. During the test, visual impression (willingness to eat, palatability, comfort, warmth, and anxiety) and thermal sensations were self-reported using visual analog scales. Core (intra-aural) and peripheral (toe) temperatures were continuously recorded 10 min before and 60 min after ingestion. Blue soup significantly decreased willingness to eat, palatability, comfort, and warmth ratings, and significantly increased anxiety feelings compared to the white and yellow soups. After ingestion, the blue soup showed significantly smaller satiety ratings and the tendency of lower thermal sensation scores of the whole body compared to the white and yellow soups. Moreover, a significantly greater increase in toe temperature was found with the yellow soup than the white or blue soup. In conclusion, this study provides new evidence that the colors of hot food may modulate postprandial satiety, thermal sensations and peripheral temperature. Such effects of color may be useful for dietary strategies for individuals who need to control their appetite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Absolute rate measurement by light modulation - ESR technique

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K Y; Gaspar, P P

    1977-01-01

    A rate constant is deduced for the reaction of tert-butoxy radicals and trimethylsilane from the measurement of the phase shift between the modulated light source and the ESR signal of trimethylsilyl radical. The rate constant was found to be 3 x 10/sup -2/M/sup -1/. sec/sup -1/ at -50/sup 0/C.

  18. Beam-quality measurements using a spatial light modulator

    CSIR Research Space (South Africa)

    Schulze, C

    2012-11-01

    Full Text Available We present a fast and easy technique for measuring the beam propagation ratio, M2, of laser beams using a spatial light modulator. Our technique is based on digitally simulating the free-space propagation of light, thus eliminating the need...

  19. Plasma flow velocity measurements using a modulated Michelson interferometer

    NARCIS (Netherlands)

    Howard, J.; Meijer, F. G.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (C) 1997 Elsevier Science S.A.

  20. Efficiency Measurement Using a Motor-Dynamo Module

    Science.gov (United States)

    Ng, Pun-hon; Wong, Siu-ling; Mak, Se-yuen

    2009-01-01

    In this article, we describe a simple method which can be used to measure the efficiency of a low power dc motor, a motor-converted dynamo and a coupled motor-dynamo module as a function of the speed of rotation. The result can also be used to verify Faraday's law of electromagnetic induction. (Contains 1 table and 8 figures.)

  1. Chemical and thermal modulation of molecular motor activities

    Science.gov (United States)

    Hong, Weili

    Molecular motors of kinesin and dynein families are responsible for various intracellular activities, from long distance movement of organelles, vesicles, protein complexes, and mRNAs to powering mitotic processes. They can take nanometer steps using chemical energy from the hydrolysis of ATP (adenosine triphosphate), and their dysfunction is involved in many neurodegenerative diseases that require long distance transport of cargos. Here I report on the study of the properties of molecular motors at a single-molecule level using optical trappings. I first studied the inhibition properties of kinesin motors by marine natural compound adociasulfates. I showed that adociasulfates compete with microtubules for binding to kinesins and thus inhibit kinesins' activity. Although adociasulfates are a strong inhibitor for all kinesin members, they show a much higher inhibition effect for conventional kinesins than for mitotic kinesins. Thus adociasulfates can be used to specifically inhibit conventional kinesins. By comparing the inhibition of kinesins by two structurally similar adociasulfates, one can see that the negatively charged sulfate residue of adociasulfates can be replaced by other negative residues and thus make it possible for adociasulfate-derived compounds to be more cell permeable. Kinesins and dyneins move cargos towards opposite directions along a microtubule. Cargos with both kinesins and dyneins attached often move bidirectionally due to undergoing a tug-of-war between the oppositely moving kinesin and dynein motors. Here I studied the effect of temperature on microtubule-based kinesin and dynein motor transport. While kinesins' and dyneins' velocities are closely matched above 15 °C, below this temperature the dyneins' velocity decreases much faster than the kinesins'. The kinesins' and dyneins' forces do not measurably change with temperature. The results suggest that temperature has significant effects on bidirectional transport and can be used to

  2. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Science.gov (United States)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  3. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse-Helmreich, Carissa J., E-mail: carissahelmreich@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States); Corbin, Rob, E-mail: rcorbin@terrapower.com [TerraPower, LLC, 330 120th Ave NE, Suite 100, Bellevue, WA 98005 (United States); McDeavitt, Sean M., E-mail: mcdeavitt@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States)

    2014-03-15

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  4. Measurement of thermal diffusivity of depleted uranium metal microspheres

    International Nuclear Information System (INIS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-01-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal

  5. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    Science.gov (United States)

    Barbagallo, C.; Malgioglio, G. L.; Petrone, G.; Cammarata, G.

    2017-05-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

  6. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    International Nuclear Information System (INIS)

    Barbagallo, C; Petrone, G; Cammarata, G; Malgioglio, G L

    2017-01-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers. (paper)

  7. Thermal behavior and phase identification of Valsartan by standard and temperature-modulated differential scanning calorimetry.

    Science.gov (United States)

    Skotnicki, Marcin; Gaweł, Agnieszka; Cebe, Peggy; Pyda, Marek

    2013-10-01

    Thermal behavior of angiotensin II type 1 (AT1) receptor antagonist, Valsartan (VAL), was examined employing thermogravimetric analysis (TGA), standard differential scanning calorimetry (DSC) and temperature-modulated differential scanning calorimetry (TMDSC). The stability of VAL was measured by TGA from 25 to 600°C. Decomposition of Valsartan starts around 160°C. The DSC curve shows two endotherms, occurring around 80°C and 100°C, related to evaporation of water and enthalpy relaxation, respectively. Valsartan was identified by DSC as an amorphous material and it was confirmed by X-ray powder diffraction. The glass transition of fresh Valsartan appears around 76°C (fictive temperature). TMDSC allows separation of the total heat flow rate into reversing and nonreversing parts. The nonreversing curve corresponds to the enthalpy relaxation and the reversing curve shows changes of heat capacity around 94°C. In the second run, TMDSC curve shows the glass transition process occurring at around 74°C. Results from standard DSC and TMDSC of Valsartan were compared over the whole range of temperature.

  8. Thermal sensation during mild hyperthermia is modulated by acute postural change in humans.

    Science.gov (United States)

    Takeda, Ryosuke; Imai, Daiki; Suzuki, Akina; Ota, Akemi; Naghavi, Nooshin; Yamashina, Yoshihiro; Hirasawa, Yoshikazu; Yokoyama, Hisayo; Miyagawa, Toshiaki; Okazaki, Kazunobu

    2016-12-01

    Thermal sensation represents the primary stimulus for behavioral and autonomic thermoregulation. We assessed whether the sensation of skin and core temperatures for the driving force of behavioral thermoregulation was modified by postural change from the supine (Sup) to sitting (Sit) during mild hyperthermia. Seventeen healthy young men underwent measurements of noticeable increase and decrease (±0.1 °C/s) of skin temperature (thresholds of warm and cold sensation on the skin, 6.25 cm 2 of area) at the forearm and chest and of the whole-body warm sensation in the Sup and Sit during normothermia (NT; esophageal temperature (T es ), ∼36.6 °C) and mild hyperthermia (HT; T es , ∼37.2 °C; lower legs immersion in 42 °C of water). The threshold for cold sensation on the skin at chest was lower during HT than NT in the Sit (P sensation on the skin at both sites remained unchanged with changes in body posture or temperature. The whole-body warm sensation was higher during HT than NT in both postures and higher in the Sit than Sup during both NT and HT (all, P sensation during mild hyperthermia is modulated by postural change from supine to sitting to sense lesser cold on the skin and more whole-body warmth.

  9. Thermal and Electrical Characterization of a Semi-Transparent Dye-Sensitized Photovoltaic Module under Real Operating Conditions

    Directory of Open Access Journals (Sweden)

    Cristina Cornaro

    2018-01-01

    Full Text Available Dye-sensitized solar cell technology is having an important role in renewable energy research due to its features and low-cost manufacturing processes. Devices based on this technology appear very well suited for integration into glazing systems due to their characteristics of transparency, color tuning and manufacturing directly on glass substrates. Field data of thermal and electrical characteristics of dye-sensitized solar modules (DSM are important since they can be used as input of building simulation models for the evaluation of their energy saving potential when integrated into buildings. However, still few studies in the literature provide this information. The study presented here aims to contribute to fill this lack providing a thermal and electrical characterization of a DSM in real operating conditions using a method developed in house. This method uses experimental data coming from test boxes exposed outdoor and dynamic simulation to provide thermal transmittance (U-value and solar heat gain coefficient (SHGC of a DSM prototype. The device exhibits a U-value of 3.6 W/m2·K, confirmed by an additional measurement carried on in the lab using a heat flux meter, and a SHGC of 0.2, value compliant with literature results. Electrical characterization shows an increase of module power with respect to temperature resulting DSM being suitable for integration in building facades.

  10. Simultaneous measurement of thermal conductivity and heat capacity by flash thermal imaging methods

    Science.gov (United States)

    Tao, N.; Li, X. L.; Sun, J. G.

    2017-06-01

    Thermal properties are important for material applications involved with temperature. Although many measurement methods are available, they may not be convenient to use or have not been demonstrated suitable for testing of a wide range of materials. To address this issue, we developed a new method for the nondestructive measurement of the thermal effusivity of bulk materials with uniform property. This method is based on the pulsed thermal imaging-multilayer analysis (PTI-MLA) method that has been commonly used for testing of coating materials. Because the test sample for PTI-MLA has to be in a two-layer configuration, we have found a commonly used commercial tape to construct such test samples with the tape as the first-layer material and the bulk material as the substrate. This method was evaluated for testing of six selected solid materials with a wide range of thermal properties covering most engineering materials. To determine both thermal conductivity and heat capacity, we also measured the thermal diffusivity of these six materials by the well-established flash method using the same experimental instruments with a different system setup. This paper provides a description of these methods, presents detailed experimental tests and data analyses, and discusses measurement results and their comparison with literature values.

  11. Welding pool measurement using thermal array sensor

    Science.gov (United States)

    Cho, Chia-Hung; Hsieh, Yi-Chen; Chen, Hsin-Yi

    2015-08-01

    Selective laser melting (SLM) is an additive manufacturing (AM) technology that uses a high-power laser beam to melt metal powder in chamber of inert gas. The process starts by slicing the 3D CAD data as a digital information source into layers to create a 2D image of each layer. Melting pool was formed by using laser irradiation on metal powders which then solidified to consolidated structure. In a selective laser melting process, the variation of melt pool affects the yield of a printed three-dimensional product. For three dimensional parts, the border conditions of the conductive heat transport have a very large influence on the melt pool dimensions. Therefore, melting pool is an important behavior that affects the final quality of the 3D object. To meet the temperature and geometry of the melting pool for monitoring in additive manufacturing technology. In this paper, we proposed the temperature sensing system which is composed of infrared photodiode, high speed camera, band-pass filter, dichroic beam splitter and focus lens. Since the infrared photodiode and high speed camera look at the process through the 2D galvanometer scanner and f-theta lens, the temperature sensing system can be used to observe the melting pool at any time, regardless of the movement of the laser spot. In order to obtain a wide temperature detecting range, 500 °C to 2500 °C, the radiation from the melting pool to be measured is filtered into a plurality of radiation portions, and since the intensity ratio distribution of the radiation portions is calculated by using black-body radiation. The experimental result shows that the system is suitable for melting pool to measure temperature.

  12. Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Sanna F.; Knipe, Kevin; Manero, Albert; Raghavan, Seetha [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Meid, Carla; Wischek, Janine; Bartsch, Marion [German Aerospace Center (DLR), Institute of Materials Research, 51147 Cologne (Germany); Okasinski, John; Almer, Jonathan [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Karlsson, Anette M. [Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115 (United States)

    2013-08-15

    Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along with variations in collection parameters are compared for their ability to attain high-resolution XRD data from the internal layers. This study displays the ability to monitor in situ, the response of the internal layers within the TBC, while implementing a thermal gradient across the thickness of the coated sample. The thermal setup maintained coating surface temperatures in the range of operating conditions, while monitoring the substrate cooling, for a controlled thermal gradient. Through variation in measurement location and beam parameters, sufficient intensities are obtained from the internal layers which can be used for depth resolved strain measurements. Results are used to establish the various techniques for obtaining XRD measurements through multi-layered coating systems and their outcomes will pave the way towards goals in achieving realistic in situ testing of these coatings.

  13. Miniaturized module for the wireless transmission of measurements with Bluetooth.

    Science.gov (United States)

    Roth, H; Schwaibold, M; Moor, C; Schöchlin, J; Bolz, A

    2002-01-01

    The wiring of patients for obtaining medical measurements has many disadvantages. In order to limit these, a miniaturized module was developed which digitalizes analog signals and sends the signal wirelessly to the receiver using Bluetooth. Bluetooth is especially suitable for this application because distances of up to 10 m are possible with low power consumption and robust transmission with encryption. The module consists of a Bluetooth chip, which is initialized in such a way by a microcontroller that connections from other bluetooth receivers can be accepted. The signals are then transmitted to the distant end. The maximum bit rate of the 23 mm x 30 mm module is 73.5 kBit/s. At 4.7 kBit/s, the current consumption is 12 mA.

  14. Modeling of Short-Circuit-Related Thermal Stress in Aged IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Iannuzzo, Francesco; Uhrenfeldt, Christian

    2017-01-01

    In this paper, the thermal stress on bond wires of aged IGBT modules under short-circuit conditions has been studied with respect to different solder delamination levels. To ensure repeatable test conditions, ad-hoc DBC (direct bond copper) samples with delaminated solder layers have been purposely...... in the surface temperature distribution, which confirms the hypothesis that short-circuit events produce significantly uneven stresses on bond wires....

  15. Prediction of Short-Circuit-Related Thermal Stress in Aged IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Iannuzzo, Francesco; Uhrenfeldt, Christian

    2016-01-01

    In this paper, the thermal stress on bond wires of aged IGBT modules under short-circuit conditions has been studied with respect to different solder delamination levels. To ensure repeatable test conditions, ad-hoc DBC (direct bond copper) samples with delaminated solder layers have been purposely...... in the surface temperature distribution which confirms the hypothesis that short-circuit events produce significantly uneven stresses on bond wires....

  16. Thermal Conductivity Measurement and Analysis of Fully Ceramic Microencapsulated fuel

    International Nuclear Information System (INIS)

    Lee, H. G.; Kim, D. J.; Park, J. Y.; Kim, W. J.; Lee, S. J.

    2015-01-01

    FCM nuclear fuel is composed of tristructural isotropic(TRISO) fuel particle and SiC ceramic matrix. SiC ceramic matrix play an essential part in protecting fission product. In the FCM fuel concept, fission product is doubly protected by TRISO coating layer and SiC ceramic matrix in comparison with the current commercial UO2 fuel system of LWR. In addition to a safety enhancement of FCM fuel, thermal conductivity of SiC ceramic matrix is better than that of UO2 fuel. Because the centerline temperature of FCM fuel is lower than that of the current UO2 fuel due to the difference of thermal conductivity of fuel, an operational release of fission products from the fuel can be reduced. SiC ceramic has attracted for nuclear fuel application due to its high thermal conductivity properties with good radiation tolerant properties, a low neutron absorption cross-section and a high corrosion resistance. Thermal conductivity of ceramic matrix composite depends on the thermal conductivity of each component and the morphology of reinforcement materials such as fibers and particles. There are many results about thermal conductivity of fiber-reinforced composite like as SiCf/SiC composite. Thermal conductivity of SiC ceramics and FCM pellets with the volume fraction of TRISO particles were measured and analyzed by analytical models. Polycrystalline SiC ceramics and FCM pellets with TRISO particles were fabricated by hot press sintering with sintering additives. Thermal conductivity of the FCM pellets with TRISO particles of 0 vol.%, 10 vol.%, 20 vol.%, 30 vol.% and 40 vol.% show 68.4, 52.3, 46.8, 43.0 and 34.5 W/mK, respectively. As the volume fraction of TRISO particles increased, the measured thermal conductivity values closely followed the prediction of Maxwell's equation

  17. Preliminary Studies Of A Phase Modulation Technique For Measuring Chromaticity

    International Nuclear Information System (INIS)

    Tan, C.-Y.

    2006-01-01

    The classical method for measuring chromaticity is to slowly modulate the RF frequency and then measure the betatron tune excursion. The technique that is discussed in this paper instead modulates the phase of the RF and then the chromaticity is obtained by phase demodulating the betatron tune. This technique requires knowledge of the betatron frequency in real time in order for the phase to be demodulated. Fortunately, the Tevatron has a tune tracker based on the phase locked loop principle which fits this requirement. A preliminary study with this technique has showed that it is a promising method for doing continuous chromaticity measurement and raises the possibility of doing successful chromaticity feedback with it

  18. Gravity modulation of thermal instability in a viscoelastic fluid saturated anisotropic porous medium

    Energy Technology Data Exchange (ETDEWEB)

    Bhadauria, Beer S. [Babasaheb Bhimrao Ambedkar Univ., Lucknow (India). Dept. of Applied Mathematics and Statistics; Banaras Hindu Univ., Varanasi (India). Dept. of Mathematics; Srivastava, Atul K. [Banaras Hindu Univ., Varanasi (India). Dept. of Mathematics; Sacheti, Nirmal C.; Chandran, Pallath [Sultan Qaboos Univ., Muscat (Oman). Dept. of Mathematics

    2012-01-15

    The present paper deals with a thermal instability problem in a viscoelastic fluid saturating an anisotropic porous medium under gravity modulation. To find the gravity modulation effect, the gravity field is considered in two parts: a constant part and an externally imposed time-dependent periodic part. The time-dependent part of the gravity field, which can be realized by shaking the fluid, has been represented by a sinusoidal function. Using Hill's equation and the Floquet theory, the convective threshold has been obtained. It is found that gravity modulation can significantly affect the stability limits of the system. Further, we find that there is a competition between the synchronous and subharmonic modes of convection at the onset of instability. Effects of various parameters on the onset of instability have also been discussed. (orig.)

  19. 25Gb/s 1V-driving CMOS ring modulator with integrated thermal tuning.

    Science.gov (United States)

    Li, Guoliang; Zheng, Xuezhe; Yao, Jin; Thacker, Hiren; Shubin, Ivan; Luo, Ying; Raj, Kannan; Cunningham, John E; Krishnamoorthy, Ashok V

    2011-10-10

    We report a high-speed ring modulator that fits many of the ideal qualities for optical interconnect in future exascale supercomputers. The device was fabricated in a 130 nm SOI CMOS process, with 7.5 μm ring radius. Its high-speed section, employing PN junction that works at carrier-depletion mode, enables 25 Gb/s modulation and an extinction ratio >5 dB with only 1V peak-to-peak driving. Its thermal tuning section allows the device to work in broad wavelength range, with a tuning efficiency of 0.19 nm/mW. Based on microwave characterization and circuit modeling, the modulation energy is estimated ~7 fJ/bit. The whole device fits in a compact 400 μm2 footprint.

  20. Double modulation pyrometry: A radiometric method to measure surface temperatures of directly irradiated samples

    Science.gov (United States)

    Potamias, Dimitrios; Alxneit, Ivo; Wokaun, Alexander

    2017-09-01

    The design, implementation, calibration, and assessment of double modulation pyrometry to measure surface temperatures of radiatively heated samples in our 1 kW imaging furnace is presented. The method requires that the intensity of the external radiation can be modulated. This was achieved by a rotating blade mounted parallel to the optical axis of the imaging furnace. Double modulation pyrometry independently measures the external radiation reflected by the sample as well as the sum of thermal and reflected radiation and extracts the thermal emission as the difference of these signals. Thus a two-step calibration is required: First, the relative gains of the measured signals are equalized and then a temperature calibration is performed. For the latter, we transfer the calibration from a calibrated solar blind pyrometer that operates at a different wavelength. We demonstrate that the worst case systematic error associated with this procedure is about 300 K but becomes negligible if a reasonable estimate of the sample's emissivity is used. An analysis of the influence of the uncertainties in the calibration coefficients reveals that one (out of the five) coefficient contributes almost 50% to the final temperature error. On a low emission sample like platinum, the lower detection limit is around 1700 K and the accuracy typically about 20 K. Note that these moderate specifications are specific for the use of double modulation pyrometry at the imaging furnace. It is mainly caused by the difficulty to achieve and maintain good overlap of the hot zone with a diameter of about 3 mm Full Width at Half Height and the measurement spot both of which are of similar size.

  1. Double modulation pyrometry: A radiometric method to measure surface temperatures of directly irradiated samples.

    Science.gov (United States)

    Potamias, Dimitrios; Alxneit, Ivo; Wokaun, Alexander

    2017-09-01

    The design, implementation, calibration, and assessment of double modulation pyrometry to measure surface temperatures of radiatively heated samples in our 1 kW imaging furnace is presented. The method requires that the intensity of the external radiation can be modulated. This was achieved by a rotating blade mounted parallel to the optical axis of the imaging furnace. Double modulation pyrometry independently measures the external radiation reflected by the sample as well as the sum of thermal and reflected radiation and extracts the thermal emission as the difference of these signals. Thus a two-step calibration is required: First, the relative gains of the measured signals are equalized and then a temperature calibration is performed. For the latter, we transfer the calibration from a calibrated solar blind pyrometer that operates at a different wavelength. We demonstrate that the worst case systematic error associated with this procedure is about 300 K but becomes negligible if a reasonable estimate of the sample's emissivity is used. An analysis of the influence of the uncertainties in the calibration coefficients reveals that one (out of the five) coefficient contributes almost 50% to the final temperature error. On a low emission sample like platinum, the lower detection limit is around 1700 K and the accuracy typically about 20 K. Note that these moderate specifications are specific for the use of double modulation pyrometry at the imaging furnace. It is mainly caused by the difficulty to achieve and maintain good overlap of the hot zone with a diameter of about 3 mm Full Width at Half Height and the measurement spot both of which are of similar size.

  2. NCTM workshop splinter session, IR thermal measurement instruments

    Science.gov (United States)

    Kaplan, Herbert

    1989-06-01

    The splinter session dealing with commercial industrial thermal measurement state-of-the-hardware had a total attendance of 15. Two papers were presented in the splinter session as follows: (1) Development of an Infrared Imaging System for the Surface Tension Driven Convection Experiment, Alexander D. Pline, NASA LeRC; (2) A Space-qualified PtSi Thermal Imaging System, Robert W. Astheimer, Barnes Engineering Div., EDO Corp. In addition a brief description of SPRITE detector technology was presented by Richard F. Leftwich of Magnovox. As anticipated, the discussions were concerned mainly with thermal imaging figures of merit rather than those for point measurement instruments. The need for uniform guidelines whereby infrared thermal imaging instruments could be specified and evaluated was identified as most important, particularly where temperature measurements are required. Presently there are differences in the way different manufacturers present significant performance parameters in their instrument data sheets. Furthermore, the prospective user has difficulty relating these parameters to actual measurement needs, and procedures by which performance can be verified are poorly defined. The current availability of powerful thermal imaging diagnostic software was discussed.

  3. Caliper variable sonde for thermal conductivity measurements in situ

    Energy Technology Data Exchange (ETDEWEB)

    Oelsner, C; Leischner, H; Pischel, S

    1968-01-01

    For the measurement of the thermal conductivity of the formations surrounding a borehole, a sonde having variable diameter (consisting of an inflatable rubber cylinder with heating wires embedded in its wall) is described. The conditions for the usual sonde made of metal are no longer fulfilled, but the solution to the problem of determining the thermal conductivity from the temperature rise is given, based on an approach by Carslaw and Jaeger, which contains the Bessel functions of the second kind. It is shown that a simpler solution for large values of time can be obtained through the Laplace transformation, and the necessary series developments for computer application are also given. The sonde and the necessary measuring circuitry are described. Tests measurements have indicated that the thermal conductivity can be determined with this sonde with a precision of + 10%.

  4. Thermal Expansion of Vitrified Blood Vessels Permeated with DP6 and Synthetic Ice Modulators

    Science.gov (United States)

    Eisenberg, David P.; Taylor, Michael J.; Jimenez-Rios, Jorge L.; Rabin, Yoed

    2014-01-01

    This study provides thermal expansion data for blood vessels permeated with the cryoprotective cocktail DP6, when combined with selected synthetic ice modulators (SIMs): 12% polyethylene glycol 400, 6% 1,3-cyclohexanediol, and 6% 2,3-butanediol. The general classification of SIMs includes molecules that modulate ice nucleation and growth, or possess properties of stabilizing the amorphous state, by virtue of their chemical structure and at concentrations that are not explained on a purely colligative basis. The current study is part of an ongoing effort to characterize thermo-mechanical effects on structural integrity of cryopreserved materials, where thermal expansion is the driving mechanism to thermo-mechanical stress. This study focuses on the lower part of the cryogenic temperature range, where the cryoprotective agent (CPA) behaves as a solid for all practical applications. By combining results obtained in the current study with literature data on the thermal expansion in the upper part of the cryogenic temperature range, unified thermal expansion curves are presented. PMID:24769313

  5. Nanoscale phase engineering of thermal transport with a Josephson heat modulator

    Science.gov (United States)

    Fornieri, Antonio; Blanc, Christophe; Bosisio, Riccardo; D'Ambrosio, Sophie; Giazotto, Francesco

    2016-03-01

    Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect, which manifests itself both in charge and energy transport. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics, and is expected to be a key tool in a number of nanoscience fields, including solid-state cooling, thermal isolation, radiation detection, quantum information and thermal logic. Here, we show the realization of the first balanced Josephson heat modulator designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters, heat pumps and time-dependent electronic engines.

  6. Thermal Stress Analysis and Structure Parameter Selection for a Bi2Te3-Based Thermoelectric Module

    Science.gov (United States)

    Gao, Jun-Ling; Du, Qun-Gui; Zhang, Xiao-Dan; Jiang, Xin-Qiang

    2011-05-01

    The output power and conversion efficiency of thermoelectric modules (TEMs) are mainly determined by their material properties, i.e., Seebeck coefficient, electrical resistivity, and thermal conductivity. In practical applications, due to the influence of the harsh environment, the mechanical properties of TEMs should also be considered. Using the finite-element analysis (FEA) model in ANSYS software, we present the thermal stress distribution of a TEM based on the anisotropic mechanical properties and thermoelectric properties of hot-pressed materials. By analyzing the possibilities of damage along the cleavage plane of Bi2Te3-based thermoelectric materials and by optimizing the structure parameters, a TEM with better mechanical performance is obtained. Thus, a direction for improving the thermal stress resistance of TEMs is presented.

  7. Thermal conductivity of a film of single walled carbon nanotubes measured with infrared thermal imager

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    Heat dissipation has restricted the modern miniaturization trend with the development of electronic devices. Theoretically proven to be with high axial thermal conductivity, single walled carbon nanotubes (SWNT) have long been expected to cool down the nanoscale world. Even though the tube-tube contact resistance limits the capability of heat transfer of the bulk film, the high intrinsic thermal conductivity of SWNT still glorify the application of films of SWNT network as a thermal interface material. In this work, we proposed a new method to straightly measure the thermal conductivity of SWNT film. We bridged two cantilevered Si thin plate with SWNT film, and kept a steady state heat flow in between. With the infrared camera to record the temperature distribution, the Si plates with known thermal conductivity can work as a reference to calculate the heat flux going through the SWNT film. Further, the thermal conductivity of the SWNT film can be obtained through Fourier's law after deducting the effect of thermal radiation. The sizes of the structure, the heating temperature, the vacuum degree and other crucial impact factors are carefully considered and analyzed. The author Y. F. was supported through the Advanced Integration Science Innovation Education and Research Consortium Program by the Ministry of Education, Culture, Sport, Science and Technology.

  8. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K.; Gabanska, B.; Igielski, A.; Krynicka, E.; Woznicka, U. [Institute of Nuclear Physics, Cracow (Poland)

    1993-12-31

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a {sup 3}He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs.

  9. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Gabanska, B.; Igielski, A.; Krynicka, E.; Woznicka, U.

    1993-01-01

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a 3 He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs

  10. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K; Gabanska, B; Igielski, A; Krynicka, E; Woznicka, U [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-31

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a {sup 3}He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs.

  11. Measurement methodology of natural radioactivity in the thermal establishments

    International Nuclear Information System (INIS)

    Ameon, R.; Robe, M.C.

    2004-11-01

    The thermal baths have been identified as an activity susceptible to expose to ionizing radiations the workers through the natural sources of radon and radon 220. The new regulation obliges these facilities to realize radioactivity measurements. The principal ways of exposure are radon and its daughters inhalation,, exposure to gamma radiation, ingestion of radioelements in thermal waters. I.R.S.N. proposes two methods of measurements of the natural radioactivity in application to the regulation relative to the protection of persons and workers. Some principles to reduce exposure to radon are reminded. (N.C.)

  12. Thermal measurement a requirement for monolithic microwave integrated circuit design

    OpenAIRE

    Hopper, Richard; Oxley, C. H.

    2008-01-01

    The thermal management of structures such as Monolithic Microwave Integrated Circuits (MMICs) is important, given increased circuit packing densities and RF output powers. The paper will describe the IR measurement technology necessary to obtain accurate temperature profiles on the surface of semiconductor devices. The measurement procedure will be explained, including the device mounting arrangement and emissivity correction technique. The paper will show how the measurement technique has be...

  13. Thermal conductivity of the cryoprotective cocktail DP6 in cryogenic temperatures, in the presence and absence of synthetic ice modulators.

    Science.gov (United States)

    Ehrlich, Lili E; Malen, Jonathan A; Rabin, Yoed

    2016-10-01

    The thermal conductivity of the cryoprotective agent (CPA) cocktail DP6 in combination with synthetic ice modulators (SIMs) is measured in this study, using a transient hot-wire method. DP6 is a mixture of 3 M dimethyl sulfoxide (DMSO) and 3 M propylene glycol, which received significant attention in the cryobiology community in recent years. Tested SIMs include 6% 1,3Cyclohexanediol, 6% 2,3Butanediol, and 12% PEG400 (percentage by volume). This study integrates the scanning cryomacroscope for visual verification of crystallization and vitrification events. It is demonstrated that the thermal conductivity of the vitrifying CPA cocktail decreases monotonically with the decreasing temperature down to -180 °C. By contrast, the thermal conductivity of the crystalline material increases with decreasing temperature in the same temperature range. Results of this study demonstrate that the thermal conductivity may vary by three fold between the amorphous and crystalline phases of DP6 below the glass transition temperature of DP6 (Tg = -119 °C). The selected SIMs demonstrate the ability to inhibit crystallization in DP6, even at subcritical cooling rates. An additional ice suppression capability is observed by the Euro-Collins as a vehicle solution, disproportionate to its volume ratio in the cocktail. The implication of the observed thermal conductivity differences between the amorphous and crystalline phases of the same cocktail on cryopreservation simulations is significant in some cases and must be taken into account in thermal analyses of cryopreservation protocols. Copyright © 2016. Published by Elsevier Inc.

  14. Quantitative Method to Measure Thermal Conductivity of One-Dimensional Nanostructures Based on Scanning Thermal Wave Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Bae; Chung, Jae Hun; Hwang, Gwang Seok; Jung, Eui Han; Kwon, Oh Myoung [Korea University, Seoul (Korea, Republic of)

    2014-12-15

    We present a method to quantitatively measure the thermal conductivity of one-dimensional nanostructures by utilizing scanning thermal wave microscopy (STWM) at a nanoscale spatial resolution. In this paper, we explain the principle for measuring the thermal diffusivity of one-dimensional nanostructures using STWM and the theoretical analysis procedure for quantifying the thermal diffusivity. The SWTM measurement method obtains the thermal conductivity by measuring the thermal diffusivity, which has only a phase lag relative to the distance corresponding to the transferred thermal wave. It is not affected by the thermal contact resistances between the heat source and nanostructure and between the nanostructure and probe. Thus, the heat flux applied to the nanostructure is accurately obtained. The proposed method provides a very simple and quantitative measurement relative to conventional measurement techniques.

  15. A study of mini-channel thermal module design for achieving high stability and high capability in electronic cooling

    International Nuclear Information System (INIS)

    Wang, Hsiang-Li; Wu, Huang-Ching; Kong Wang, S.; Hung, Tzu-Chen; Yang, Ruey-Jen

    2013-01-01

    In this study, pressure drop and heat transfer characteristics of multiple-mini-channel thermal modules were investigated quantitatively. The flow channels, which were mounted on one side of a copper test section, were designed in three types: (1) the first module consists of fourteen straight and parallel channels with a rectangular cross section of 1 mm × 3 mm, (2) the second module consists of fourteen gradually widening channels with a U-shaped cross section starting from an inlet section of 0.5 mm × 3 mm and increasing to an outlet section of 1 mm × 3 mm, and (3) the third module is similar to the second module except for the rectangular cross section. Visual observations and the measured boiling curves show that, in the straight channels, some bubbles cannot be flushed out of the channels fast enough, so they tend to flow back and accumulate at the entrance. This results in a rather dry channel condition for CHF (critical heat flux) to occur for the cases with low flow rates. For the widening channel modules, no occurrence of CHF was observed under an even lower operating pressure in an attempt to induce the incipient of CHF. Under a similar temperature rise at the channel exit, the maximum heat removal rate of the widening channels reaches 27 W/cm 2 which is at least twice as high as that of the straight channels. -- Highlights: ► Three mini-channel modules were designed, and experiments were carried out on pressure drop and heat transfer characteristics. ► Comparisons were made between one regular straight-channel module and two widening-channel modules with rectangular and U-shaped cross sections. ► It was found that the widening channels yield a stable two-phase heat transfer mode with no occurrence of CHF due to a better movement of the bubbles and the absence of backflow which causes accumulation of bubbles commonly occur at the entrance of the straight-shaped parallel channels. ► The maximum heat removal rate of the widening channels reaches

  16. Measurement of the diffusion length of thermal neutrons inside graphite

    International Nuclear Information System (INIS)

    Ertaud, A.; Beauge, R.; Fauquez, H.; De Laboulay, H.; Mercier, C.; Vautrey, L.

    1948-11-01

    The diffusion length of thermal neutrons inside a given industrial graphite is determined by measuring the neutron density inside a parallelepipedal piling up of graphite bricks (2.10 x 2.10 x 2.442 m). A 3.8 curies (Ra α → Be) source is placed inside the parallelepipedal block of graphite and thin manganese detectors are used. Corrections are added to the unweighted measurements to take into account the effects of the damping of supra-thermal neutrons in the measurement area. These corrections are experimentally deduced from the differential measurements made with a cadmium screen interposed between the source and the first plane of measurement. An error analysis completes the report. The diffusion length obtained is: L = 45.7 cm ± 0.3. The average density of the graphite used is 1.76 and the average apparent density of the piling up is 1.71. (J.S.)

  17. Temperature measurement by thermal strain imaging with diagnostic power ultrasound, with potential for thermal index determination.

    Science.gov (United States)

    Liang, Hai-Dong; Zhou, Li-Xia; Wells, Peter N T; Halliwell, Michael

    2009-05-01

    Over the years, there has been a substantial increase in acoustic exposure in diagnostic ultrasound as new imaging modalities with higher intensities and frame rates have been introduced; and more electronic components have been packed into the probe head, so that there is a tendency for it to become hotter. With respect to potential thermal effects, including those which may be hazardous occurring during ultrasound scanning, there is a correspondingly growing need for in vivo techniques to guide the operator as to the actual temperature rise occurring in the examined tissues. Therefore, an in vivo temperature estimator would be of considerable practical value. The commonly-used method of tissue thermal index (TI) measurement with a hydrophone in water could underestimate the actual value of TI (in one report by as much as 2.9 times). To obtain meaningful results, it is necessary to map the temperature elevation in 2-D (or 3-D) space. We present methodology, results and validation of a 2-D spatial and temporal thermal strain ultrasound temperature estimation technique in phantoms, and its apparently novel application in tracking the evolution of heat deposition at diagnostic exposure levels. The same ultrasound probe is used for both transmission and reception. The displacement and thermal strain estimation methods are similar to those used in high-intensity focused ultrasound thermal monitoring. The use of radiofrequency signals permits the application of cross correlation as a similarity measurement for tracking feature displacement. The displacement is used to calculate the thermal strain directly related to the temperature rise. Good agreement was observed between the temperature rise and the ultrasound power and scan duration. Thermal strain up to 1.4% was observed during 4000-s scan. Based on the results obtained for the temperature range studied in this work, the technique demonstrates potential for applicability in phantom (and possibly in vivo tissue

  18. Method and apparatus for measuring thermal neutron characteristics

    International Nuclear Information System (INIS)

    Johnstone, C.W.

    1983-01-01

    The thermal neutron decay characteristics of an earth formation are measured by detecting indications of the thermal neutron concentration in the formation during a selected set of two measurement intervals following irradiation of the formation with a burst of fast neutrons. These measurement intervals may comprise a sequence of time gates following a delay after the neutron burst. The duration of the neutron bursts, of the delay between the burst and the start of the sequence, and of the individual time gates, may all be adjusted by a common, selected one of a finite number of scale factor values. The set of two measurement intervals is selected from among a number of possible sets as a function of a previously measured value of the decay characteristic. Each measurement interval set is used over only a specific range of decay characteristic values for which it has been determined, in accordance with a previously established relationship between the decay characteristic value and a function of the thermal neutron concentration measurements for the set, to afford enhanced statistical accuracy in the measured value of the decay characteristic. (author)

  19. A 3D thermal runaway propagation model for a large format lithium ion battery module

    International Nuclear Information System (INIS)

    Feng, Xuning; Lu, Languang; Ouyang, Minggao; Li, Jiangqiu; He, Xiangming

    2016-01-01

    In this paper, a 3D thermal runaway (TR) propagation model is built for a large format lithium ion battery module. The 3D TR propagation model is built based on the energy balance equation. Empirical equations are utilized to simplify the calculation of the chemical kinetics for TR, whereas equivalent thermal resistant layer is employed to simplify the heat transfer through the thin thermal layer. The 3D TR propagation model is validated by experiment and can provide beneficial discussions on the mechanisms of TR propagation. According to the modeling analysis of the 3D model, the TR propagation can be delayed or prevented through: 1) increasing the TR triggering temperature; 2) reducing the total electric energy released during TR; 3) enhancing the heat dissipation level; 4) adding extra thermal resistant layer between adjacent batteries. The TR propagation is successfully prevented in the model and validated by experiment. The model with 3D temperature distribution provides a beneficial tool for researchers to study the TR propagation mechanisms and for engineers to design a safer battery pack. - Highlights: • A 3D thermal runaway (TR) propagation model for Li-ion battery pack is built. • The 3D TR propagation model can fit experimental results well. • Temperature distributions during TR propagation are presented using the 3D model. • Modeling analysis provides solutions for the prevention of TR propagation. • Quantified solutions to prevent TR propagation in battery pack are discussed.

  20. Thermal Hydraulic Analysis of K-DEMO Single Blanket Module for Preliminary Accident Analysis using MELCOR

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sung Bo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    To develop the Korean fusion commercial reactor, preliminary design concept for K-DEMO (Korean fusion demonstration reactor) has been announced by NFRI (National Fusion Research Institute). This pre-conceptual study of K-DEMO has been introduced to identify technical details of a fusion power plant for the future commercialization of fusion reactor in Korea. Before this consideration, to build the K-DEMO, accident analysis is essential. Since the Fukushima accident, which is severe accident from unexpected disaster, safety analysis of nuclear power plant has become important. The safety analysis of both fission and fusion reactors is deemed crucial in demonstrating the low radiological effect of these reactors on the environment, during severe accidents. A risk analysis of K-DEMO should be performed, as a prerequisite for the construction of a fusion reactor. In this research, thermal-hydraulic analysis of single blanket module of K-DEMO is conducted for preliminary accident analysis for K-DEMO. Further study about effect of flow distributer is conducted. The normal K-DEMO operation condition is applied to the boundary condition and simulated to verify the material temperature limit using MELCOR. MELCOR is fully integrated, relatively fast-running code developed by Sandia National Laboratories. MELCOR had been used for Light Water Reactors and fusion reactor version of MELCOR was developed for ITER accident analysis. This study shows the result of thermal-hydraulic simulation of single blanket module with MELCOR which is severe accident code for nuclear fusion safety analysis. The difference of mass flow rate for each coolant channel with or without flow distributer is presented. With flow distributer, advantage of broadening temperature gradient in the K-DEMO blanket module and increase mass flow toward first wall is obtained. This can enhance the safety of K-DEMO blanket module. Most 13 .deg. C temperature difference in blanket module is obtained.

  1. Safe affordable fission engine (SAFE 30) module conductivity test thermal model correlation

    International Nuclear Information System (INIS)

    Roman, Jose

    2001-01-01

    The SAFE 30 is a simple, robust space fission power system that is comprised of several independent modules. Each module contains 4 fuel tubes bonded to a central heatpipe. Fission energy is conducted from the fuel tubes to the heatpipe, which in turn transfers the energy to a power conversion system. This paper benchmarks a thermal model of the SAFE 30 with actual test data from simulated SAFE 30 module tests. Two 'dummy' SAFE 30 modules were fabricated - each consisted of 4 1-inch dia. tubes (simulating the fuel tubes) bonded to a central '1' dia. tube (simulating the heatpipe). In the first module the fuel tubes were simply brazed to the heatpipe along the line of contact (leaving void space in the interstices), and in the second module the tubes and heatpipe were brazed via tri-cusps that completely fill the interstices between the tubes. In these tests, fission energy is simulated by placing resistance heaters within each of the 4 fuel tubes. The tests were conducted in a vacuum chamber in 4 configurations: tri-cusps filled with and without an outer insulation wrap, and no tri-cusps with and without an outer insulation wrap. The baseline SAFE 30 configuration uses the brazed tri-cusps. During the tests, the power applied to the heaters was varied in a stepwise fashion, until a steady-state temperature profile was reached. These temperature levels varied between 773 K and 1073 K. To benchmark the thermal model, the input energy and chamber surface temperature were used as boundary conditions for the model. The analytical results from the nodes at the same location as the test thermocouples were plotted again test data to determinate the accuracy of the analysis. The unknown variables on the analysis are the radiation emissivity of the pipe and chamber and the radiation view factor between the module and the chamber. A correlation was determined using a parametric analysis by varying the surface emissivity and view factor until a good match was reached. This

  2. Digital module for neutron flux measurement by Campbell method

    International Nuclear Information System (INIS)

    Baratte, G.

    1987-02-01

    The study reported here concerns a wide range measurement channel for reactor control instrumentation but it may also be useful for specific measurements requiring the Campbell method. A wide range measurement channel allows the processing of the signal issued from a single fission chamber so it's possible to insure control of nuclear reactors in three different running modes: pulse processing, fluctuations and current. The study described in this note includes three parts: - the analogical wide range neutron measurement channel is presented in the first chapter; the fluctuation mode is thoroughly studied; the results of tests and proper limitations of analogical processing are summarized. A theoretical study of the neutron flux measurement by numerical calculation of the fluctuation signal variance is given in the second chapter. The digital module is described in the third chapter; the results of experiments are analysed. The validity of the digital method is proved by means of a practical realisation. The performances obtained with the digital fluctuation test model may be compared with those given by the analogical fluctuation channel which can be used for the control of lower fission rates. The digital module may also be used for any fluctuation measurement where very short response time and broad spectral band of analysis are not strictly necessary [fr

  3. Measuring high-frequency responses of an electro-optic phase modulator based on dispersion induced phase modulation to intensity modulation conversion

    Science.gov (United States)

    Zhang, Shangjian; Wang, Heng; Wang, Yani; Zou, Xinhai; Zhang, Yali; Liu, Shuang; Liu, Yong

    2014-11-01

    We investigate the phase modulation to intensity modulation conversion in dispersive fibers for measuring frequency responses of electro-optic phase modulators, and demonstrate two typical measurements with cascade path and fold-back path. The measured results achieve an uncertainty of less than 2.8% within 20 GHz. Our measurements show stable and repeatable results because the optical carrier and its phase-modulated sidebands are affected by the same fiber impairments. The proposed method requires only dispersive fibers and works without any small-signal assumption, which is applicable for swept frequency measurement at different driving levels and operating wavelengths.

  4. Equipment for thermal neutron flux measurements in reactor R2

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E; Nilsson, T; Claeson, S

    1960-04-15

    For most of the thermal neutron flux measurements in reactor R2 cobalt wires will be used. The loading and removal of these wires from the reactor core will be performed by means of a long aluminium tube and electromagnets. After irradiation the wires will be scanned in a semi-automatic device.

  5. Thermal lensing measurement from the coefficient of defocus aberration

    CSIR Research Space (South Africa)

    Bell, Teboho

    2016-03-01

    Full Text Available We measured the thermally induced lens from the coefficient of defocus aberration using a Shack-Hartmann wavefront sensor (SHWFS). As a calibration technique, we infer the focal length of standard lenses probed by a collimated Gaussian beam...

  6. Thermal investigation of lithium-ion battery module with different cell arrangement structures and forced air-cooling strategies

    International Nuclear Information System (INIS)

    Wang, Tao; Tseng, K.J.; Zhao, Jiyun; Wei, Zhongbao

    2014-01-01

    Highlights: • Three-dimensional CFD model with forced air cooling are developed for battery modules. • Impact of different air cooling strategies on module thermal characteristics are investigated. • Impact of different model structures on module thermal responses are investigated. • Effect of inter-cell spacing on cell thermal characteristics are also studied. • The optimal battery module structure and air cooling strategy is recommended. - Abstract: Thermal management needs to be carefully considered in the lithium-ion battery module design to guarantee the temperature of batteries in operation within a narrow optimal range. This article firstly explores the thermal performance of battery module under different cell arrangement structures, which includes: 1 × 24, 3 × 8 and 5 × 5 arrays rectangular arrangement, 19 cells hexagonal arrangement and 28 cells circular arrangement. In addition, air-cooling strategies are also investigated by installing the fans in the different locations of the battery module to improve the temperature uniformity. Factors that influence the cooling capability of forced air cooling are discussed based on the simulations. The three-dimensional computational fluid dynamics (CFD) method and lumped model of single cell have been applied in the simulation. The temperature distributions of batteries are quantitatively described based on different module patterns, fan locations as well as inter-cell distance, and the conclusions are arrived as follows: when the fan locates on top of the module, the best cooling performance is achieved; the most desired structure with forced air cooling is cubic arrangement concerning the cooling effect and cost, while hexagonal structure is optimal when focus on the space utilization of battery module. Besides, the optimized inter-cell distance in battery module structure has been recommended

  7. Design, modeling and performance analysis of dual channel semitransparent photovoltaic thermal hybrid module in the cold environment

    International Nuclear Information System (INIS)

    Singh, Sonveer; Agrawal, Sanjay; Avasthi, D.V.

    2016-01-01

    Highlights: • Thermal modeling of novel dual channel semitransparent PVT hybrid module. • Exergy and carbon credit analysis has been performed. • Annual performance has been evaluated for Srinagar (India). • There are improvements in results for case-I as compared to case-II. - Abstract: In this work, thermal modeling and performance analysis of the dual channel semitransparent photovoltaic thermal (DCSPVT) module has been carried out. For extracting heat associated with the lower and upper surface of the solar cell, two channels have been proposed; (i) one is above the solar cell called upper channel and (ii) second is below the solar cell called lower channel. Firstly, thermal modeling of DCSPVT module has been developed. After that, performance analysis of the above system has been carried out for Srinagar, Indian climatic condition. Performance in terms of electrical gain (EG), thermal gain (TG), overall exergy gain (OEG), overall thermal gain (OTG), electrical efficiency (EE) and overall exergy efficiency (OEE) of the DCSPVT module (case-I) have been compared with single channel semitransparent photovoltaic thermal (SCSPVT) hybrid module (case-II). The average improvement in EG, TG, OEG, OTG of the case-I have been observed by 71.51%, 34.57%, 5.78% and 35.41% respectively as compared to case-II.

  8. Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering

    Science.gov (United States)

    Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.

    1999-01-01

    The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.

  9. Measurements of He II Thermal Counterflow Using PIV Technique

    International Nuclear Information System (INIS)

    Zhang, T.; Van Sciver, S.W.

    2004-01-01

    Our previous experiments on the measurements of He II thermal counterflow using Particle Image Velocimetry (PIV) have shown that there exists a substantial discrepancy between the measured and theoretical values of normal fluid velocity. It was assumed that this is due to the slip velocity between tracer particles and liquid helium. In the present work, tracer particles with a much smaller mean diameter and a more uniform size distribution were selected in order to reduce the effect of slip velocity, and an improved two phase fluidized bed technique was used to introduce the particles into liquid helium. The normal fluid velocity of thermal counterflow was then measured using the PIV technique at various heat fluxes and bath temperatures. The experimental results, however, still show the existence of discrepancy between PIV measured particle velocities and the theoretical normal fluid velocity. A preliminary explanation of these results is given based on an interaction of tracer particles with the superfluid component in the He II

  10. Osmotically and thermally isolated forward osmosis-membrane distillation (fo-md) integrated module for water treatment applications

    KAUST Repository

    Ghaffour, Noreddine

    2016-09-01

    An integrated forward osmosis-membrane distillation (FO-MD) module and systems and methods incorporating the module is disclosed providing higher efficiencies and using less energy. The FO-MD module is osmotically and thermally isolated. The isolation can prevent mixing of FO draw solution/FO permeate and MD feed, and minimize dilution of FO draw solution and cooling of MD feed. The module provides MD feed solution and FO draw solution streams that flow in the same module but are separated by an isolation barrier. The osmotically and thermally isolated FO-MD integrated module, systems and methods offer higher driving forces of both FO and MD processes, higher recovery, and wider application than previously proposed hybrid FO- MD systems.

  11. Osmotically and thermally isolated forward osmosis-membrane distillation (fo-md) integrated module for water treatment applications

    KAUST Repository

    Ghaffour, NorEddine; Francis, Lijo; Li, Zhenyu; Valladares, Rodrigo; Alsaadi, Ahmad S.; Ghdaib, Muhannad Abu; Amy, Gary L.

    2016-01-01

    An integrated forward osmosis-membrane distillation (FO-MD) module and systems and methods incorporating the module is disclosed providing higher efficiencies and using less energy. The FO-MD module is osmotically and thermally isolated. The isolation can prevent mixing of FO draw solution/FO permeate and MD feed, and minimize dilution of FO draw solution and cooling of MD feed. The module provides MD feed solution and FO draw solution streams that flow in the same module but are separated by an isolation barrier. The osmotically and thermally isolated FO-MD integrated module, systems and methods offer higher driving forces of both FO and MD processes, higher recovery, and wider application than previously proposed hybrid FO- MD systems.

  12. Mechanical modulation method for ultrasensitive phase measurements in photonics biosensing.

    Science.gov (United States)

    Patskovsky, S; Maisonneuve, M; Meunier, M; Kabashin, A V

    2008-12-22

    A novel polarimetry methodology for phase-sensitive measurements in single reflection geometry is proposed for applications in optical transduction-based biological sensing. The methodology uses altering step-like chopper-based mechanical phase modulation for orthogonal s- and p- polarizations of light reflected from the sensing interface and the extraction of phase information at different harmonics of the modulation. We show that even under a relatively simple experimental arrangement, the methodology provides the resolution of phase measurements as low as 0.007 deg. We also examine the proposed approach using Total Internal Reflection (TIR) and Surface Plasmon Resonance (SPR) geometries. For TIR geometry, the response appears to be strongly dependent on the prism material with the best values for high refractive index Si. The detection limit for Si-based TIR is estimated as 10(-5) in terms Refractive Index Units (RIU) change. SPR geometry offers much stronger phase response due to a much sharper phase characteristics. With the detection limit of 3.2*10(-7) RIU, the proposed methodology provides one of best sensitivities for phase-sensitive SPR devices. Advantages of the proposed method include high sensitivity, simplicity of experimental setup and noise immunity as a result of a high stability modulation.

  13. Efficiency maximization and performance evaluation of hybrid dual channel semitransparent photovoltaic thermal module using fuzzyfied genetic algorithm

    International Nuclear Information System (INIS)

    Singh, Sonveer; Agrawal, Sanjay

    2016-01-01

    Highlights: • Thermal modeling of novel dual channel semitransparent photovoltaic thermal hybrid module. • Efficiency maximization and performance evaluation of dual channel photovoltaic thermal module. • Annual performance has been evaluated for Srinagar, Jodhpur, Bangalore and New Delhi (India). • There are improvements in results for optimized system as compared to un-optimized system. - Abstract: The work has been carried out in two steps; firstly the parameters of hybrid dual channel semitransparent photovoltaic thermal module has been optimized using a fuzzyfied genetic algorithm. During the course of optimization, overall exergy efficiency is considered as an objective function and different design parameters of the proposed module have been optimized. Fuzzy controller is used to improve the performance of genetic algorithms and the approach is called as a fuzzyfied genetic algorithm. In the second step, the performance of the module has been analyzed for four cities of India such as Srinagar, Bangalore, Jodhpur and New Delhi. The performance of the module has been evaluated for daytime 08:00 AM to 05:00 PM and annually from January to December. It is to be noted that, an average improvement occurs in electrical efficiency of the optimized module, simultaneously there is also a reduction in solar cell temperature as compared to un-optimized module.

  14. Method for Measuring Thermal Conductivity of Small Samples Having Very Low Thermal Conductivity

    Science.gov (United States)

    Miller, Robert A.; Kuczmarski, Maria a.

    2009-01-01

    This paper describes the development of a hot plate method capable of using air as a standard reference material for the steady-state measurement of the thermal conductivity of very small test samples having thermal conductivity on the order of air. As with other approaches, care is taken to ensure that the heat flow through the test sample is essentially one-dimensional. However, unlike other approaches, no attempt is made to use heated guards to block the flow of heat from the hot plate to the surroundings. It is argued that since large correction factors must be applied to account for guard imperfections when sample dimensions are small, it may be preferable to simply measure and correct for the heat that flows from the heater disc to directions other than into the sample. Experimental measurements taken in a prototype apparatus, combined with extensive computational modeling of the heat transfer in the apparatus, show that sufficiently accurate measurements can be obtained to allow determination of the thermal conductivity of low thermal conductivity materials. Suggestions are made for further improvements in the method based on results from regression analyses of the generated data.

  15. A low-noise measurement system for scanning thermal microscopy resistive nanoprobes based on a transformer ratio-arm bridge

    Science.gov (United States)

    Świątkowski, Michał; Wojtuś, Arkadiusz; Wielgoszewski, Grzegorz; Rudek, Maciej; Piasecki, Tomasz; Jóźwiak, Grzegorz; Gotszalk, Teodor

    2018-04-01

    Atomic force microscopy (AFM) is a widely used technology for the investigation and characterization of nanomaterials. Its functionality can be easily expanded by applying dedicated extension modules, which can measure the electrical conductivity or temperature of a sample. In this paper, we introduce a transformer ratio-arm bridge setup dedicated to AFM-based thermal imaging. One of the key features of the thermal module is the use of a low-power driving signal that prevents undesirable tip heating during resistance measurement, while the other is the sensor location in a ratio-arm transformer bridge working in the audio frequency range and ensuring galvanic isolation of the tip, enabling contact-mode scanning of electronic circuits. The proposed expansion module is compact and it can be integrated onto the AFM head close to the cantilever. The calibration process and the resolution of 11 mK of the proposed setup are shown.

  16. High-Temperature Thermal Diffusivity Measurements of Silicate Glasses

    Science.gov (United States)

    Pertermann, M.; Hofmeister, A. M.; Whittington, A. G.; Spera, F. J.; Zayac, J.

    2005-12-01

    Transport of heat in geologically relevant materials is of great interest because of its key role in heat transport, magmatism and volcanic activity on Earth. To better understand the thermal properties of magmatic materials at high temperatures, we measured the thermal diffusivity of four synthetic end-member silicate glasses with the following compositions: albite (NaAlSi3O8), orthoclase (KAlSi3O8), anorthite (CaAl2Si2O8), and diopside (CaMgSi2O6). Thermal diffusivity measurements were conducted with the laser-flash technique and data were acquired from room temperature to a maximum temperature near 1100°C, depending on the glass transition temperature. The presence of sub-mm sized bubbles in one of the orthoclase samples had no discernable effect on measured diffusivities. At room temperature, the three feldspar-type glasses have thermal diffusivity (D) values of 0.58-0.61 mm2/s, whereas the diopside glass has 0.52 mm2/s. With increasing temperature, D decreases by 5-10% (relative) for all samples and becomes virtually constant at intermediate temperatures. At higher temperatures, the anorthite and diopside glasses exhibit significant drops in thermal diffusivity over a 50-100°C interval, correlating with previously published heat capacity changes near the glass transition for these compositions. For anorthite, D (in mm2/s) decreases from 0.48 at 750-860°C to 0.36 at 975-1075°C; for diopside, D changes from 0.42 at 630-750°C to 0.30 at 850-910°C, corresponding to relative drops of 24 and 29%, respectively. Albite and orthoclase glasses do not exhibit this change and also lack significant changes in heat capacity near the glass transition. Instead, D is constant at 400-800°C for albite, and for orthoclase values go through a minimum at 500-600°C before increasing slightly towards 1100°C but it never exceeds the room temperature D. Our data on thermal diffusivity correlate closely with other thermophysical properties. Thus, at least in case of simple

  17. Argonne National Laboratory's thermal plume measurements: instruments and techniques

    International Nuclear Information System (INIS)

    Van Loon, L.S.; Frigo, A.A.; Paddock, R.A.

    1977-12-01

    Instrumentation and techniques were developed at Argonne National Laboratory for measuring the three-dimensional temperature structure of thermal plumes from power plants, along with the limnological, meteorological, and plant operating conditions affecting their behavior. The equipment and procedures were designed to provide field data for use in evaluating predictive models that describe thermal plume behavior, and over 100 sets of these data have been collected. The instrument systems and techniques employed in a typical thermal discharge survey are highly integrated. Continuous monitoring of ambient and plant conditions is coupled with plume mapping from a moving survey boat. The instantaneous location of the boat together with subsurface temperature measurements from a towed thermistor chain provide a quasisynoptic view of the plume structure. Real-time, onboard display of the boat path and vertical temperatures supply feedback to investigators for determining the extent and spatial resolution of measurements required. The unique design, reliability, accuracy, calibration, and historical development of the components of these integrated systems are described. Survey system interfaces with data handling and processing techniques are also explained. Special supportive studies to investigate plume dynamics, values of eddy diffusivities, time-temperature histories of water parcels in thermal plumes, and rapid changes in plume shape are also described along with instrumentation used

  18. Gas loop - continuous measurement of thermal and fast neutron fluxes

    International Nuclear Information System (INIS)

    Droulers, Y.; Pleyber, G.; Sciers, P.; Maurin, G.

    1964-01-01

    The measurement method described in this report can be applied both to thermal and fast neutron fluxes. A description is given of two practical applications in each of these two domains. This method is particularly suitable for measurements carried out on 'loop' type equipment. The measurement of the relative flux variations are carried out with an accuracy of 5 per cent. The choice of the shape of the gas circuit leaves a considerable amount of liberty for the adaptation of the measurement circuit to the experimental conditions. (authors) [fr

  19. Activation measurements for thermal neutrons. Part J. Evaluation of thermal neutron transmission factors

    International Nuclear Information System (INIS)

    Egbert, Stephen D.

    2005-01-01

    In order to relate thermal neutron activation measurements in samples to the calculated free-in-air thermal neutron activation levels given in Chapter 3, use is made of sample transmission factors. Transmission factors account for the modification of the fluence and activation at each sample's in situ location. For the purposes of this discussion, the transmission factor (TF) is defined as the ratio of the in situ sample activation divided by the free-in-air (FIA) activation at a height of 1 m above ground at the same ground range. The procedures for calculation of TF's and example results are presented in this section. (author)

  20. Using thermalizers in measuring 'Ukryttia' object's FCM neutron fluxes

    CERN Document Server

    Krasnyanskaya, O G; Odinokin, G I; Pavlovich, V N

    2003-01-01

    The results of research of a thermalizer (heater) width influence on neutron thermalization efficiency during FCM neutron flux measuring in the 'Ukryttia' are described. The calculations of neutron flux densities were performed by the Monte-Carlo method with the help of computer code MCNP-4C for FCM different models.Three possible installations of detectors were considered: on FCM surface,inside the FCM, and inside the concrete under the FCM layer. It was shown,that in order to increase the sensitivity of neutron detectors in intermediate and fast neutrons field,and consequently, to decrease the dependence of the readings of spectral distribution of neutron flux,it is necessary to position the detector inside the so-called thermalizer or heater. The most reasonable application of thick 'heaters' is the situation, when the detector is placed on FCM surface.

  1. Thermal and Electrical Conductivity Measurements of CDA 510 Phosphor Bronze

    Science.gov (United States)

    Tuttle, James E.; Canavan, Edgar; DiPirro, Michael

    2009-01-01

    Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze's electrical and thermal conductivity values have been published, there is significant variation among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). The heat conducted into the JWST instrument stage is dominated by these harnesses, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to just keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment which measured the electrical and thermal conductivity of this material between 4 and 295 Kelvin.

  2. ICRF power deposition profile and determination of the electron thermal diffusivity by modulation experiments in JET

    International Nuclear Information System (INIS)

    Gambier, D.J.; Evrard, M.P.; Adam, J.

    1990-01-01

    The power deposition profile in the ion cyclotron range of frequencies (ICRF) has been investigated experimentally in JET by means of a square wave modulated RF perturbation. The study has been conducted in D(H) and D( 3 He) plasmas for two heating scenarios. In D( 3 He) plasmas and for central heating in a scenario where mode conversion to Bernstein waves is accessible, the direct power deposition profile on electrons has been derived. It accounts for 15% of the total coupled power and extends over 25% of the minor radius. Outside the RF power deposition zone, the electron thermal diffusivity χ e inside the inversion radius surface (r i ) can be estimated through observation of the diffusive electronic transport. In discharges without monster sawteeth and for a low central temperature gradient (∇T e (r ≤ r i ) ≤ ∇T e (r ≥ r i ) approx. = 5 keV·m -1 ) the value obtained is small (approx. =0.24 +- 0.05 m 2 · s -1 ), typically ten times lower than χ e values deduced from heat pulse propagation in similar discharges at radii larger than the inversion radius. For the D(H) minority heating scheme, a large fraction of the ICRF modulated power is absorbed by minority ions, and the minority tail is modulated with a characteristic ion-electron (i-e) slowing-down time. In this scheme, electron heating occurs only through collisions with the minority ion tail and no modulation of the electron temperature is observed in sawtoothing discharges. This is interpreted as a consequence of the long i-e equipartition time, acting as an integrator for the modulated ICRF signal. Finally, a correlation between the time of the sawtooth crash and the periodic turn-off of the ICRF power is found and its consequence for modulation experiments is reviewed. (author). 22 refs, 16 figs

  3. Sinusoidal modulation analysis for optical system MTF measurements.

    Science.gov (United States)

    Boone, J M; Yu, T; Seibert, J A

    1996-12-01

    The modulation transfer function (MTF) is a commonly used metric for defining the spatial resolution characteristics of imaging systems. While the MTF is defined in terms of how an imaging system demodulates the amplitude of a sinusoidal input, this approach has not been in general use to measure MTFs in the medical imaging community because producing sinusoidal x-ray patterns is technically difficult. However, for optical systems such as charge coupled devices (CCD), which are rapidly becoming a part of many medical digital imaging systems, the direct measurement of modulation at discrete spatial frequencies using a sinusoidal test pattern is practical. A commercially available optical test pattern containing spatial frequencies ranging from 0.375 cycles/mm to 80 cycles/mm was sued to determine the MRF of a CCD-based optical system. These results were compared with the angulated slit method of Fujita [H. Fujita, D. Tsia, T. Itoh, K. Doi, J. Morishita, K. Ueda, and A. Ohtsuka, "A simple method for determining the modulation transfer function in digital radiography," IEEE Trans. Medical Imaging 11, 34-39 (1992)]. The use of a semiautomated profiled iterated reconstruction technique (PIRT) is introduced, where the shift factor between successive pixel rows (due to angulation) is optimized iteratively by least-squares error analysis rather than by hand measurement of the slit angle. PIRT was used to find the slit angle for the Fujita technique and to find the sine-pattern angle for the sine-pattern technique. Computer simulation of PIRT for the case of the slit image (a line spread function) demonstrated that it produced a more accurate angle determination than "hand" measurement, and there is a significant difference between the errors in the two techniques (Wilcoxon Signed Rank Test, p < 0.001). The sine-pattern method and the Fujita slit method produced comparable MTF curves for the CCD camera evaluated.

  4. Non-thermal continuous and modulated electromagnetic radiation fields effects on sleep EEG of rats☆

    Science.gov (United States)

    Mohammed, Haitham S.; Fahmy, Heba M.; Radwan, Nasr M.; Elsayed, Anwar A.

    2012-01-01

    In the present study, the alteration in the sleep EEG in rats due to chronic exposure to low-level non-thermal electromagnetic radiation was investigated. Two types of radiation fields were used; 900 MHz unmodulated wave and 900 MHz modulated at 8 and 16 Hz waves. Animals has exposed to radiation fields for 1 month (1 h/day). EEG power spectral analyses of exposed and control animals during slow wave sleep (SWS) and rapid eye movement sleep (REM sleep) revealed that the REM sleep is more susceptible to modulated radiofrequency radiation fields (RFR) than the SWS. The latency of REM sleep increased due to radiation exposure indicating a change in the ultradian rhythm of normal sleep cycles. The cumulative and irreversible effect of radiation exposure was proposed and the interaction of the extremely low frequency radiation with the similar EEG frequencies was suggested. PMID:25685416

  5. Modulation instability of ion thermal waves in a pair-ion plasma containing charged dust impurities

    International Nuclear Information System (INIS)

    Sabry, R.

    2008-01-01

    Modulation instability of ion thermal waves (ITWs) is investigated in a plasma composed of positive and negative ions as well as a fraction of stationary charged (positive or negative) dust impurities. For this purpose, a linear dispersion relation and a nonlinear Schroedinger equation are derived. The latter admits localized envelope solitary wave solutions of bright (pulses) and dark (holes, voids) type. The envelope soliton depends on the intrinsic plasma parameters. It is found that modulation instability of ITWs is significantly affected by the presence of positively/negatively charged dust grains. The findings of this investigation should be useful in understanding the stable electrostatic wave packet acceleration mechanisms in pair-ion plasma, and also enhances our knowledge on the occurrence of instability associated to the existence of charged dust impurities in pair-ion plasmas. Our results should be of relevance for laboratory plasmas.

  6. Non-thermal continuous and modulated electromagnetic radiation fields effects on sleep EEG of rats

    Directory of Open Access Journals (Sweden)

    Haitham S. Mohammed

    2013-03-01

    Full Text Available In the present study, the alteration in the sleep EEG in rats due to chronic exposure to low-level non-thermal electromagnetic radiation was investigated. Two types of radiation fields were used; 900 MHz unmodulated wave and 900 MHz modulated at 8 and 16 Hz waves. Animals has exposed to radiation fields for 1 month (1 h/day. EEG power spectral analyses of exposed and control animals during slow wave sleep (SWS and rapid eye movement sleep (REM sleep revealed that the REM sleep is more susceptible to modulated radiofrequency radiation fields (RFR than the SWS. The latency of REM sleep increased due to radiation exposure indicating a change in the ultradian rhythm of normal sleep cycles. The cumulative and irreversible effect of radiation exposure was proposed and the interaction of the extremely low frequency radiation with the similar EEG frequencies was suggested.

  7. Water cooling thermal power measurement in a vacuum diffusion pump

    Directory of Open Access Journals (Sweden)

    Luís Henrique Cardozo Amorin

    2012-04-01

    Full Text Available Diffusion vacuum pumps are used both in industry and in laboratory science for high vacuum production. For its operation they must be refrigerated, and it is done by circulating water in open circuit. Considering that, vacuum systems stays operating by hours, the water consumption may be avoided if the diffusion vacuum pumps refrigeration were done in closed circuit. However, it is necessary to know the diffusion vacuum pump thermal power (the heat transferred to circulate water by time units to implement one of these and get in the refrigeration system dimension. In this paper the diffusion vacuum pump thermal power was obtained by measuring water flow and temperature variation and was calculated through the heat quantity variation equation time function. The thermal power value was 935,6 W, that is 397 W smaller and 35 W bigger than, respectively, the maximum and minimum diffusion pump thermal power suggested by its operation manual. This procedure have been shown useful to precisely determine the diffusion pump thermal power or of any other system that needs to be refrigerated in water closed circuit.

  8. MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY

    International Nuclear Information System (INIS)

    Garrett, A.; Kurzeja, R.; Villa-Aleman, E.; Tuckfield, C.; Pendergast, M.

    2009-01-01

    The Savannah River National Laboratory (SRNL) collected thermal imagery and ground truth data at two commercial power plant cooling lakes to investigate the applicability of laboratory empirical correlations between surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper (1] that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that the skewness of the temperature distribution derived from cooling lake thermal images correlates with instantaneous wind speed measured at the same location. SRNL collected thermal imagery, surface meteorology and water temperatures from helicopters and boats at the Comanche Peak and H. B. Robinson nuclear power plant cooling lakes. SRNL found that decreasing skewness correlated with increasing wind speed, as was the case for the laboratory experiments. Simple linear and orthogonal regression models both explained about 50% of the variance in the skewness - wind speed plots. A nonlinear (logistic) regression model produced a better fit to the data, apparently because the thermal convection and resulting skewness are related to wind speed in a highly nonlinear way in nearly calm and in windy conditions

  9. Thermal conductivity of mesoporous films measured by Raman spectroscopy

    Science.gov (United States)

    Stoib, B.; Filser, S.; Petermann, N.; Wiggers, H.; Stutzmann, M.; Brandt, M. S.

    2014-04-01

    We measure the in-plane thermal conductance of mesoporous Ge and SiGe thin films using the Raman-shift method and, based on a finite differences simulation accounting for the geometry of the sample, extract the in-plane thermal conductivity. For a suspended thin film of laser-sintered SiGe nanoparticles doped with phosphorus, we find an effective in-plane thermal conductivity of 0.05 W/m K in vacuum for a temperature difference of 400 K and a mean temperature of 500 K. Under similar conditions, the effective in-plane thermal conductivity of a laser-sintered undoped Ge nanoparticle film is 0.5 W/m K. Accounting for a porosity of approximately 50%, the normalized thermal conductivities are 0.1 W/m K and 1 W/m K, respectively. The thermoelectric performance is discussed, considering that the electrical in-plane conductivity is also affected by the mesoporosity.

  10. Bulk temperature measurement in thermally striped pipe flows

    International Nuclear Information System (INIS)

    Lemure, N.; Olvera, J.R.; Ruggles, A.E.

    1995-12-01

    The hot leg flows in some Pressurized Water Reactor (PWR) designs have a temperature distribution across the pipe cross-section. This condition is often referred to as a thermally striped flow. Here, the bulk temperature measurement of pipe flows with thermal striping is explored. An experiment is conducted to examine the feasibility of using temperature measurements on the external surface of the pipe to estimate the bulk temperature of the flow. Simple mixing models are used to characterize the development of the temperature profile in the flow. Simple averaging techniques and Backward Propagating Neural Net are used to predict bulk temperature from the external temperature measurements. Accurate bulk temperatures can be predicted. However, some temperature distributions in the flow effectively mask the bulk temperature from the wall and cause significant error in the bulk temperature predicted using this technique

  11. Thermal transport measurements of uv laser irradiated spherical targets

    International Nuclear Information System (INIS)

    Jaanimagi, P.A.; Delettrez, J.; Henke, B.L.; Richardson, M.C.

    1985-01-01

    New measurements are presented of thermal transport in spherical geometry using time-resolved x-ray spectroscopy. We determine the time dependence of the mass ablation rate m(dot) by following the progress of the ablation surface through thin layers of material embedded at various depths below the surface of the target. These measurements made with 6 and 12 uv (351 nm) beams from OMEGA are compared to previous thermal transport data and are in qualitative agreement with detailed LILAC hydrodynamic code simulations which predict a sharp decrease in m(dot) after the peak of the laser pulse. Non-uniform laser irradiation of the target results in the anomalously high values of m(dot) measured in these experiments

  12. A generalized interface module for the coupling of spatial kinetics and thermal-hydraulics codes

    Energy Technology Data Exchange (ETDEWEB)

    Barber, D.A.; Miller, R.M.; Joo, H.G.; Downar, T.J. [Purdue Univ., West Lafayette, IN (United States). Dept. of Nuclear Engineering; Wang, W. [SCIENTECH, Inc., Rockville, MD (United States); Mousseau, V.A.; Ebert, D.D. [Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research

    1999-03-01

    A generalized interface module has been developed for the coupling of any thermal-hydraulics code to any spatial kinetics code. The coupling scheme was designed and implemented with emphasis placed on maximizing flexibility while minimizing modifications to the respective codes. In this design, the thermal-hydraulics, general interface, and spatial kinetics codes function independently and utilize the Parallel Virtual Machine software to manage cross-process communication. Using this interface, the USNRC version of the 3D neutron kinetics code, PARCX, has been coupled to the USNRC system analysis codes RELAP5 and TRAC-M. RELAP5/PARCS assessment results are presented for two NEACRP rod ejection benchmark problems and an NEA/OECD main steam line break benchmark problem. The assessment of TRAC-M/PARCS has only recently been initiated, nonetheless, the capabilities of the coupled code are presented for a typical PWR system/core model.

  13. A generalized interface module for the coupling of spatial kinetics and thermal-hydraulics codes

    International Nuclear Information System (INIS)

    Barber, D.A.; Miller, R.M.; Joo, H.G.; Downar, T.J.; Mousseau, V.A.; Ebert, D.D.

    1999-01-01

    A generalized interface module has been developed for the coupling of any thermal-hydraulics code to any spatial kinetics code. The coupling scheme was designed and implemented with emphasis placed on maximizing flexibility while minimizing modifications to the respective codes. In this design, the thermal-hydraulics, general interface, and spatial kinetics codes function independently and utilize the Parallel Virtual Machine software to manage cross-process communication. Using this interface, the USNRC version of the 3D neutron kinetics code, PARCX, has been coupled to the USNRC system analysis codes RELAP5 and TRAC-M. RELAP5/PARCS assessment results are presented for two NEACRP rod ejection benchmark problems and an NEA/OECD main steam line break benchmark problem. The assessment of TRAC-M/PARCS has only recently been initiated, nonetheless, the capabilities of the coupled code are presented for a typical PWR system/core model

  14. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    Science.gov (United States)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  15. Modulation of thermal conductivity in kinked silicon nanowires: phonon interchanging and pinching effects.

    Science.gov (United States)

    Jiang, Jin-Wu; Yang, Nuo; Wang, Bing-Shen; Rabczuk, Timon

    2013-04-10

    We perform molecular dynamics simulations to investigate the reduction of the thermal conductivity by kinks in silicon nanowires. The reduction percentage can be as high as 70% at room temperature. The temperature dependence of the reduction is also calculated. By calculating phonon polarization vectors, two mechanisms are found to be responsible for the reduced thermal conductivity: (1) the interchanging effect between the longitudinal and transverse phonon modes and (2) the pinching effect, that is, a new type of localization, for the twisting and transverse phonon modes in the kinked silicon nanowires. Our work demonstrates that the phonon interchanging and pinching effects, induced by kinking, are brand-new and effective ways in modulating heat transfer in nanowires, which enables the kinked silicon nanowires to be a promising candidate for thermoelectric materials.

  16. Pump and Flow Control Subassembly of Thermal Control Subsystem for Photovoltaic Power Module

    Science.gov (United States)

    Motil, Brian; Santen, Mark A.

    1993-01-01

    The pump and flow control subassembly (PFCS) is an orbital replacement unit (ORU) on the Space Station Freedom photovoltaic power module (PVM). The PFCS pumps liquid ammonia at a constant rate of approximately 1170 kg/hr while providing temperature control by flow regulation between the radiator and the bypass loop. Also, housed within the ORU is an accumulator to compensate for fluid volumetric changes as well as the electronics and firmware for monitoring and control of the photovoltaic thermal control system (PVTCS). Major electronic functions include signal conditioning, data interfacing and motor control. This paper will provide a description of each major component within the PFCS along with performance test data. In addition, this paper will discuss the flow control algorithm and describe how the nickel hydrogen batteries and associated power electronics will be thermally controlled through regulation of coolant flow to the radiator.

  17. Analysis of thermal issues associated with the pre-amplifier modules in the National Ignition Facility

    International Nuclear Information System (INIS)

    Lam, K.L.

    1998-01-01

    The design of the National Ignition Facility (NIF) calls for a desired temperature field of 20.00 ± 0.28 C throughout the facility. This design requirement is needed to prevent degradation of the operating performance and net yield of the NIF by heat loads generated within the facility. In particular, the potential interference of waste heat from the lighting fixtures and equipment such as the electronics racks, and pre-amplifier modules (PAMs), and its impact on the operational performance of the laser beam transport tubes and optical alignment components must be evaluated. This report describes the thermal analyses associated with the PAMs. Evaluation of thermal issues for the other equipment is discussed elsewhere

  18. The Measurement of Thermal Conductivities of Silica and Carbon Black Powders at Different pressures by Thermal COnductivity Probe

    Institute of Scientific and Technical Information of China (English)

    X.G.Liang; X.S.Ge; 等

    1992-01-01

    This investigation was done to study the gas filled powder insulation and thermal conductivity probe for the measurent of thermal conductivity of powders.The mathematical analysis showed that the heat capacity of the probe itself and the thermal rsistance between the probe and powder must be considered .The authors developed a slender probe and measured the effective thermal conductivity of sillca and carbon black powders under a variety of conditions.

  19. Impact of measurable physical phenomena on contact thermal comfort

    Science.gov (United States)

    Fojtlín, Miloš; Pokorný, Jan; Fišer, Jan; Toma, Róbert; Tuhovčák, Ján

    Cabin HVAC (Heating Ventilation and Air-conditioning) systems have become an essential part of personal vehicles as demands for comfortable transport are still rising. In fact, 85 % of the car trips in Europe are shorter than 18 km and last only up to 30 minutes. Under such conditions, the HVAC unit cannot often ensure desired cabin environment and passengers are prone to experience thermal stress. For this reason, additional comfort systems, such as heated or ventilated seats, are available on the market. However, there is no straightforward method to evaluate thermal comfort at the contact surfaces nowadays. The aim of this work is to summarise information about heated and ventilated seats. These technologies use electrical heating and fan driven air to contact area in order to achieve enhanced comfort. It is also expected, that such measures may contribute to lower energy consumption. Yet, in real conditions it is almost impossible to measure the airflow through the ventilated seat directly. Therefore, there is a need for an approach that would correlate measurable physical phenomena with thermal comfort. For this reason, a method that exploits a measurement of temperatures and humidity at the contact area is proposed. Preliminary results that correlate comfort with measurable physical phenomena are demonstrated.

  20. Impact of measurable physical phenomena on contact thermal comfort

    Directory of Open Access Journals (Sweden)

    Fojtlín Miloš

    2017-01-01

    Full Text Available Cabin HVAC (Heating Ventilation and Air-conditioning systems have become an essential part of personal vehicles as demands for comfortable transport are still rising. In fact, 85 % of the car trips in Europe are shorter than 18 km and last only up to 30 minutes. Under such conditions, the HVAC unit cannot often ensure desired cabin environment and passengers are prone to experience thermal stress. For this reason, additional comfort systems, such as heated or ventilated seats, are available on the market. However, there is no straightforward method to evaluate thermal comfort at the contact surfaces nowadays. The aim of this work is to summarise information about heated and ventilated seats. These technologies use electrical heating and fan driven air to contact area in order to achieve enhanced comfort. It is also expected, that such measures may contribute to lower energy consumption. Yet, in real conditions it is almost impossible to measure the airflow through the ventilated seat directly. Therefore, there is a need for an approach that would correlate measurable physical phenomena with thermal comfort. For this reason, a method that exploits a measurement of temperatures and humidity at the contact area is proposed. Preliminary results that correlate comfort with measurable physical phenomena are demonstrated.

  1. Robust, Rework-able Thermal Electronic Packaging: Applications in High Power TR Modules for Space

    Science.gov (United States)

    Hoffman, James Patrick; Del Castillo, Linda; Hunter, Don; Miller, Jennifer

    2012-01-01

    The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires improvements in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and are now being implemented side-by-side with more standard technology typically used in flight hardware.

  2. Non-thermal continuous and modulated electromagnetic radiation fields effects on sleep EEG of rats ?

    OpenAIRE

    Mohammed, Haitham S.; Fahmy, Heba M.; Radwan, Nasr M.; Elsayed, Anwar A.

    2012-01-01

    In the present study, the alteration in the sleep EEG in rats due to chronic exposure to low-level non-thermal electromagnetic radiation was investigated. Two types of radiation fields were used; 900 MHz unmodulated wave and 900 MHz modulated at 8 and 16 Hz waves. Animals has exposed to radiation fields for 1 month (1 h/day). EEG power spectral analyses of exposed and control animals during slow wave sleep (SWS) and rapid eye movement sleep (REM sleep) revealed that the REM sleep is more susc...

  3. Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

    Science.gov (United States)

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-05

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  4. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    Directory of Open Access Journals (Sweden)

    Shi-Zhou Xu

    2016-01-01

    Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

  5. Digital measurement system for the LHC klystron high voltage modulator.

    CERN Document Server

    Mikkelsen, Anders

    Accelerating voltage in the Large Hadron Collider (LHC) is created by a means of 16 superconducting standing wave RF cavities, each fed by a 400MHz/300kW continuous wave klystron amplifier. Part of the upgrade program for the LHC long shutdown one is to replace the obsolete analogue current and voltage measurement circuitry located in the high voltage bunkers by a new, digital system, using ADCs and optical fibres. A digital measurement card is implemented and integrated into the current HV modulator oil tank (floating at -58kV) and interfaced to the existing digital VME boards collecting the data for several klystrons at the ground potential. Measured signals are stored for the logging, diagnostics and post-mortem analysis purposes.

  6. Spatial distribution measured by the modulation transfer function

    International Nuclear Information System (INIS)

    Rossi, P.; Brice, D.K.; Doyle, B.L.

    2003-01-01

    Spatial distributions in ion micro-beam and IBA experimental practice are regularly characterized through the parameters of FWHM and tail area percentage (TF, tail fraction). Linear and stationary transducer theory allows these distributions to be described in the Fourier-dual frequency space, and provides an indirect method to evaluate them through measurement of the modulation transfer function (MTF). We suggest direct measurement of MTF by employing bar pattern grids, similar to those used for calibration of radiological equipment. Assuming spatial distributions of the form exp(-(|αx|) η ), we are able to relate the MTF measurements to the more popular FWHM and TF. This new approach to determine spatial resolution can become a standard for use by the micro-beam community

  7. Linear thermal expansion coefficient measurement technology in hot cell

    International Nuclear Information System (INIS)

    Park, Dae Gyu; Choo, Yong Sun; Ahn, Sang Bok; Hong, Kwon Pyo; Lee, K. S.

    1998-06-01

    To establish linear thermal expansion coefficient measurement technology in hot cell, we reviewed and evaluated various measuring technology by paper and these were compared with the data produced with pre-installed dilatometer in hot cell. Detailed contents are as follows; - The theory of test. - Review of characteristics for various measurement technology and compatibility with hot cell. - Review of standard testing regulations(ASTM). - System calibration of pre-installed dilatometer. - Performance test of pre-installed dilatometer. (author). 12 refs., 15 tabs., 8 figs

  8. Thermal conductivity and emissivity measurements of uranium carbides

    International Nuclear Information System (INIS)

    Corradetti, S.; Manzolaro, M.; Andrighetto, A.; Zanonato, P.; Tusseau-Nenez, S.

    2015-01-01

    Highlights: • Thermal conductivity and emissivity measurements of uranium carbides were performed. • The tested materials are candidates as targets for radioactive ion beam production. • The results are correlated with the materials composition and microstructure. - Abstract: Thermal conductivity and emissivity measurements on different types of uranium carbide are presented, in the context of the ActiLab Work Package in ENSAR, a project within the 7th Framework Program of the European Commission. Two specific techniques were used to carry out the measurements, both taking place in a laboratory dedicated to the research and development of materials for the SPES (Selective Production of Exotic Species) target. In the case of thermal conductivity, estimation of the dependence of this property on temperature was obtained using the inverse parameter estimation method, taking as a reference temperature and emissivity measurements. Emissivity at different temperatures was obtained for several types of uranium carbide using a dual frequency infrared pyrometer. Differences between the analyzed materials are discussed according to their compositional and microstructural properties. The obtainment of this type of information can help to carefully design materials to be capable of working under extreme conditions in next-generation ISOL (Isotope Separation On-Line) facilities for the generation of radioactive ion beams.

  9. High Resolution Viscosity Measurement by Thermal Noise Detection

    Directory of Open Access Journals (Sweden)

    Felipe Aguilar Sandoval

    2015-11-01

    Full Text Available An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD of thermal fluctuations together with Sader’s model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0.03 mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 µL.

  10. Measurement of thermal properties of soil and concrete samples

    DEFF Research Database (Denmark)

    Pagola, Maria Alberdi; Jensen, Rasmus Lund; Madsen, Søren

    February 2016 and February 2017. The presented work mainly consists of thermal property measurements. They become important as they form the basis for dimensioning a planned ground source heat pump installation based on closed loop vertical ground heat exchangers. This report complements the report......, the measurements of the properties of the concrete are treated. The work is extended in appendixes.......This document aims to present the laboratory work undertaken to analyse the thermal properties of the soil at two test sites in Denmark and the concrete produced by Centrum Pæle A/S, used to produce the pile heat exchangers studied in the present PhD project. The tasks have been carried out between...

  11. Thermal conductivity and PVT measurements of pentafluoroethane (refrigerant HFC-125)

    International Nuclear Information System (INIS)

    Tsvetkov, O.B.; Kletski, A.V.; Laptev, Yu.A.

    1995-01-01

    By means of the transient and steady-state coaxial cylinder methods, the thermal conductivity of pentfluoroethane was investigated at temperatures from 187 to 419 K and pressures from atmospheric to 6.0 MPa. The estimated uncertainty of the measured results is ± (2-3)%. The operation of the experimental apparatus was validated by measuring the thermal conductivity of R22 and R12. Determinations of the vapor pressure and PVT properties were carried out by a constant-volume apparatus for the temperature range 263 to 443 K, pressures up to 6 MPa, and densities from 36 to 516 kg m -3 . The uncertainties in temperature, pressure, and density are less than ±10 mK, ±0.08%, and ±0.1%, respectively

  12. Experimental and modeling analysis of thermal runaway propagation over the large format energy storage battery module with Li_4Ti_5O_1_2 anode

    International Nuclear Information System (INIS)

    Huang, Peifeng; Ping, Ping; Li, Ke; Chen, Haodong; Wang, Qingsong; Wen, Jennifer; Sun, Jinhua

    2016-01-01

    Highlights: • The heat generation and gas production of four main thermal-chemical reactions are detected. • The fire-impingement takes an unordinary thermal runaway propagation for battery module. • There is a “smoldering period” before the explosion of lithium ion battery module. • Semenov and Frank-Kamenetskii models are used to analysis and predict the onset of runaway. - Abstract: Insight of the thermal characteristics and potential flame spread over lithium-ion battery (LIB) modules is important for designing battery thermal management system and fire protection measures. Such thermal characteristics and potential flame spread are also dependent on the different anode and cathode materials as well as the electrolyte. In the present study, thermal behavior and flame propagation over seven 50 A h Li(Ni_1_/_3Mn_1_/_3Co_1_/_3)O_2/Li_4Ti_5O_1_2 large format LIBs arranged in rhombus and parallel layouts were investigated by directly heating one of the battery units. Such batteries have already been used commercially for energy storage while relatively little is known about its safety features in connection with potential runaway caused fire and explosion hazards. It was found in the present heating tests that fire-impingement resulted in elevated temperatures in the immediate vicinity of the LIBs that were in the range of between 200 °C and 900 °C. Such temperature aggravated thermal runaway (TR) propagation, resulting in rapid temperature rise within the battery module and even explosions after 20 min of “smoldering period”. The thermal runaway and subsequent fire and explosion observed in the heating test was attributed to the violent reduction of the cathode material which coexisted with the electrolyte when the temperature exceeded 260 °C. Separate laboratory tests, which measured the heat and gases generation from samples of the anode and cathode materials using C80 calorimeter, provided insight of the physical-chemistry processes inside the

  13. Parameters measurement for the thermal neutron beam in the thermal column hole of Xi’an pulse reactor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The distribution of the neutron spectra in the thermal column hole of Xi’an pulse reactor was measured with the time-of-flight method.Compared with the thermal Maxwellian theory neutron spectra,the thermal neutron spectra measured is a little softer,and the average neutron energy of the experimental spectra is about 0.042±0.01 eV.The thermal neutron fluence rate at the front end of thermal column hole,measured with gold foil activation techniques,is about 1.18×105 cm-2 s-1.The standard uncertainty of the measured thermal neutron fluence is about 3%.The spectra-averaged cross section of 197Au(n,γ) determined by the experimental thermal neutron spectra is(92.8±0.93) ×10-24 cm2.

  14. Thermal conductivity measurement below 40 K of the CFRP tubes for the Mid-Intrared Instrument mounting struts

    DEFF Research Database (Denmark)

    Shaughnessy, B. M.; Eccleston, P.; Fereday, K. J.

    2007-01-01

    The Mid-Infrared Instrument (MIRI) is one of four instruments on the James Webb Space Telescope observatory, scheduled for launch in 2013. It must be cooled to about 7 K and is supported within the telescope’s 40 K instrument module by a hexapod of carbon fibre reinforced plastic (CFRP) tubing. T....... This article describes the measurement of cryogenic thermal conductivity of the candidate CFRP. Measured thermal conductivities were about 0.05 W/m K at a mean temperature of 10 K increasing to about 0.20 W/m K at a mean temperature of 40 K....

  15. Thermal effects influencing measurements in a supersonic blowdown wind tunnel

    Directory of Open Access Journals (Sweden)

    Vuković Đorđe S.

    2016-01-01

    Full Text Available During a supersonic run of a blowdown wind tunnel, temperature of air in the test section drops which can affect planned measurements. Adverse thermal effects include variations of the Mach and Reynolds numbers, variation of airspeed, condensation of moisture on the model, change of characteristics of the instrumentation in the model, et cetera. Available data on thermal effects on instrumentation are pertaining primarily to long-run-duration wind tunnel facilities. In order to characterize such influences on instrumentation in the models, in short-run-duration blowdown wind tunnels, temperature measurements were made in the wing-panel-balance and main-balance spaces of two wind tunnel models tested in the T-38 wind tunnel. The measurements showed that model-interior temperature in a run increased at the beginning of the run, followed by a slower drop and, at the end of the run, by a large temperature drop. Panel-force balance was affected much more than the main balance. Ways of reducing the unwelcome thermal effects by instrumentation design and test planning are discussed.

  16. Thermal performance measurements on ultimate heat sinks--cooling ponds

    International Nuclear Information System (INIS)

    Hadlock, R.K.; Abbey, O.B.

    1977-12-01

    The primary objective of the studies described is to obtain the requisite data, with respect to modeling requirements, to characterize thermal performance of heat sinks for nuclear facilities existing at elevated water temperatures in result of experiencing a genuinely large heat load and responding to meteorological influence. The data should reflect thermal performance for combinations leading to worst-case meteorological influence. A geothermal water retention basin has been chosen as the site for the first measurement program and data have been obtained in the first of several experiments scheduled to be performed there. These data illustrate the thermal and water budgets during episodes of cooling from an initially high pond water bulk temperature. Monitoring proceeded while the pond experienced only meteorological and seepage influence. The data are discussed and are presented as a data volume which may be used for calculation purposes. Suggestions for future measurement programs are stated with the intent to maintain and improve relevance to nuclear ultimate heat sinks while continuing to examine the performance of the analog geothermal pond. It is further suggested that the geothermal pond, with some modification, may be a suitable site for spray pond measurements

  17. Validation of Storm Water Management Model Storm Control Measures Modules

    Science.gov (United States)

    Simon, M. A.; Platz, M. C.

    2017-12-01

    EPA's Storm Water Management Model (SWMM) is a computational code heavily relied upon by industry for the simulation of wastewater and stormwater infrastructure performance. Many municipalities are relying on SWMM results to design multi-billion-dollar, multi-decade infrastructure upgrades. Since the 1970's, EPA and others have developed five major releases, the most recent ones containing storm control measures modules for green infrastructure. The main objective of this study was to quantify the accuracy with which SWMM v5.1.10 simulates the hydrologic activity of previously monitored low impact developments. Model performance was evaluated with a mathematical comparison of outflow hydrographs and total outflow volumes, using empirical data and a multi-event, multi-objective calibration method. The calibration methodology utilized PEST++ Version 3, a parameter estimation tool, which aided in the selection of unmeasured hydrologic parameters. From the validation study and sensitivity analysis, several model improvements were identified to advance SWMM LID Module performance for permeable pavements, infiltration units and green roofs, and these were performed and reported herein. Overall, it was determined that SWMM can successfully simulate low impact development controls given accurate model confirmation, parameter measurement, and model calibration.

  18. Silicate bonding properties: Investigation through thermal conductivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzini, M; Cesarini, E; Cagnoli, G; Campagna, E; Losurdo, G; Martelli, F; Piergiovanni, F; Vetrano, F [INFN, Istituto Nazionale di Fisica Nucleare, Sez. di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Haughian, K; Hough, J; Martin, I; Reid, S; Rowan, S; Veggel, A A van, E-mail: lorenzini@fi.infn.i [SUPA, University of Glasgow, Department of Physics and Astronomy, Kelvin Building G12 8QQ Glasgow, Scotland (United Kingdom)

    2010-05-01

    A direct approach to reduce the thermal noise contribution to the sensitivity limit of a GW interferometric detector is the cryogenic cooling of the mirrors and mirrors suspensions. Future generations of detectors are foreseen to implement this solution. Silicon has been proposed as a candidate material, thanks to its very low intrinsic loss angle at low temperatures and due to its very high thermal conductivity, allowing the heat deposited in the mirrors by high power lasers to be efficiently extracted. To accomplish such a scheme, both mirror masses and suspension elements must be made of silicon, then bonded together forming a quasi-monolithic stage. Elements can be assembled using hydroxide-catalysis silicate bonding, as for silica monolithic joints. The effect of Si to Si bonding on suspension thermal conductance has therefore to be experimentally studied. A measurement of the effect of silicate bonding on thermal conductance carried out on 1 inch thick silicon bonded samples, from room temperature down to 77 K, is reported. In the explored temperature range, the silicate bonding does not seem to affect in a relevant way the sample conductance.

  19. Measurement of Turbulence Modulation by Non-Spherical Particles

    DEFF Research Database (Denmark)

    Mandø, Matthias; Rosendahl, Lasse

    2010-01-01

    The change in the turbulence intensity of an air jet resulting from the addition of particles to the flow is measured using Laser Doppler Anemometry. Three distinct shapes are considered: the prolate spheroid, the disk and the sphere. Measurements of the carrier phase and particle phase velocities...... at the centerline of the jet are carried out for mass loadings of 0.5, 1, 1.6 and particle sizes 880μm, 1350μm, 1820μm for spherical particles. For each non-spherical shape only a single size and loading are considered. The turbulence modulation of the carrier phase is found to highly dependent on the turbulence......, the particle mass flow and the integral length scale of the flow. The expression developed on basis of spherical particles only is applied on the data for the non-spherical particles. The results suggest that non-spherical particles attenuate the carrier phase turbulence significantly more than spherical...

  20. Thermally moderated hollow fiber sorbent modules in rapidly cycled pressure swing adsorption mode for hydrogen purification

    KAUST Repository

    Lively, Ryan P.; Bessho, Naoki; Bhandari, Dhaval A.; Kawajiri, Yoshiaki; Koros, William J.

    2012-01-01

    We describe thermally moderated multi-layered pseudo-monolithic hollow fiber sorbents entities, which can be packed into compact modules to provide small-footprint, efficient H2 purification/CO2 removal systems for use in on-site steam methane reformer product gas separations. Dual-layer hollow fibers are created via dry-jet, wet-quench spinning with an inner "active" core of cellulose acetate (porous binder) and zeolite NaY (69 wt% zeolite NaY) and an external sheath layer of pure cellulose acetate. The co-spun sheath layer reduces the surface porosity of the fiber and was used as a smooth coating surface for a poly(vinyl-alcohol) post-treatment, which reduced the gas permeance through the fiber sorbent by at least 7 orders of magnitude, essentially creating an impermeable sheath layer. The interstitial volume between the individual fibers was filled with a thermally-moderating paraffin wax. CO2 breakthrough experiments on the hollow fiber sorbent modules with and without paraffin wax revealed that the "passively" cooled paraffin wax module had 12.5% longer breakthrough times than the "non-isothermal" module. The latent heat of fusion/melting of the wax offsets the released latent heat of sorption/desorption of the zeolites. One-hundred rapidly cycled pressure swing adsorption cycles were performed on the "passively" cooled hollow fiber sorbents using 25 vol% CO2/75 vol% He (H2 surrogate) at 60 °C and 113 psia, resulting in a product purity of 99.2% and a product recovery of 88.1% thus achieving process conditions and product quality comparable to conventional pellet processes. Isothermal and non-isothermal dynamic modeling of the hollow fiber sorbent module and a traditional packed bed using gPROMS® indicated that the fiber sorbents have sharper fronts (232% sharper) and longer adsorbate breakthrough times (66% longer), further confirming the applicability of the new fiber sorbent approach for H2 purification. © 2012, Hydrogen Energy Publications, LLC

  1. The module CCM for the simulation of the thermal-hydraulic situation within a coolant channel

    International Nuclear Information System (INIS)

    Hoeld, A.

    2000-01-01

    A coolant channel module (Cc) will be presented which aim is to simulate, in a very general way, the thermal-hydraulic behaviour of single- and two-phase fluids flowing along a heated (or cooled) vertical, inclined or horizontal coolant channel. It is based on a theoretical drift-flux supported 3-equation mixture-fluid model describing the steady state and transient behaviour of characteristic thermal-hydraulic parameters of a single- and two-phase flow within such a channel. The module can be applied as an element within an overall theoretical model for large and complex plant assemblies (PWR and BWR core channels, parallel channels in 3D cores, primary and secondary sides of different steam generators types etc.). The model refers to a general (basic) coolant channel (BC) which can consists of different flow regimes. The BC has thus to be subdivided accordingly into a number of subchannels (SC-s). All of them can belong, however, to only two types of SC-s (single-phase fluid with subcooled water or superheated steam or a two-phase flow regime). For both of them the possibility of variable entrance or outlet positions has to be considered. For discretization purposes the BC (and thus also the SC-s) have to be subdivided into a number of (BC and SC) nodes, discretizing thus the conservation equations for mass, energy and momentum along these nodes by applying a very general spatial procedure, namely a 'modified finite volume method'. A special quadratic polygon approximation method (PAX procedure) helps then to establish a connection between nodal boundary and mean nodal parameters. Considering their constitutive equations (among them an adequate drift-flux correlation package) yields finally a set of non-linear algebraic and non-linear ordinary differential equations for the characteristic parameters of each of these SC nodes (mass flow, pressure drop, coolant temperature and/or void fraction). Based on this theory a code package (CCM) could be established

  2. Thermally moderated hollow fiber sorbent modules in rapidly cycled pressure swing adsorption mode for hydrogen purification

    KAUST Repository

    Lively, Ryan P.

    2012-10-01

    We describe thermally moderated multi-layered pseudo-monolithic hollow fiber sorbents entities, which can be packed into compact modules to provide small-footprint, efficient H2 purification/CO2 removal systems for use in on-site steam methane reformer product gas separations. Dual-layer hollow fibers are created via dry-jet, wet-quench spinning with an inner "active" core of cellulose acetate (porous binder) and zeolite NaY (69 wt% zeolite NaY) and an external sheath layer of pure cellulose acetate. The co-spun sheath layer reduces the surface porosity of the fiber and was used as a smooth coating surface for a poly(vinyl-alcohol) post-treatment, which reduced the gas permeance through the fiber sorbent by at least 7 orders of magnitude, essentially creating an impermeable sheath layer. The interstitial volume between the individual fibers was filled with a thermally-moderating paraffin wax. CO2 breakthrough experiments on the hollow fiber sorbent modules with and without paraffin wax revealed that the "passively" cooled paraffin wax module had 12.5% longer breakthrough times than the "non-isothermal" module. The latent heat of fusion/melting of the wax offsets the released latent heat of sorption/desorption of the zeolites. One-hundred rapidly cycled pressure swing adsorption cycles were performed on the "passively" cooled hollow fiber sorbents using 25 vol% CO2/75 vol% He (H2 surrogate) at 60 °C and 113 psia, resulting in a product purity of 99.2% and a product recovery of 88.1% thus achieving process conditions and product quality comparable to conventional pellet processes. Isothermal and non-isothermal dynamic modeling of the hollow fiber sorbent module and a traditional packed bed using gPROMS® indicated that the fiber sorbents have sharper fronts (232% sharper) and longer adsorbate breakthrough times (66% longer), further confirming the applicability of the new fiber sorbent approach for H2 purification. © 2012, Hydrogen Energy Publications, LLC

  3. Finite Element Model for Thermal-Structural analysis of CLIC Lab Module type 0#2

    CERN Document Server

    Moilanen, Antti; Vamvakas, Alex; Vainola, Jukka Ilmari; Doebert, Steffen

    2017-01-01

    Temperature changes lead to unwanted thermo-mechanical deformations in the components of the Compact Linear Collider (CLIC) module. There are several sources and sinks of heat around the CLIC two-beam module. Heat is generated in the components that produce, transfer, and extract radio frequency (RF) power. Excess heat is removed from the components by cooling water as well as dissipated to air by convection from the outer surfaces of the components. The ambient temperature might also vary along the tunnel during the operation of CLIC. Due to tight assembling and alignment tolerances, it is necessary to minimize the thermo-mechanical deformations in the components. In this paper, the steps of thermal-structural Finite Element Analysis (FEA) of CLIC lab module type 0#2 are described from geometry model simplification to setting up the simulation. The description is accompanied by useful hints for CATIA and ANSYS users performing similar modelling tasks. A reliable computer simulation is important for studying ...

  4. Thermal-hydraulic analysis on the whole module of water cooled ceramic breeder blanket for CFETR

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Kecheng; Ma, Xuebin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230027 (China); Cheng, Xiaoman [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Lin, Shuang [University of Science and Technology of China, Hefei, Anhui, 230027 (China); Huang, Kai [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Liu, Songlin, E-mail: slliu@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230027 (China)

    2016-11-15

    Highlights: • The 3D thermal hydraulic analysis on the whole module of WCCB is performed by CFD method. • Temperature field and mass flow distribution have been obtained. • The design of WCCB is reasonable from the perspective of thermal-hydraulics. • The scheme for further optimization has been proposed. - Abstract: The Water Cooled Ceramic Breeder blanket (WCCB) is being researched for Chinese Fusion Engineering Test Reactor (CFETR). The thermal-hydraulic analysis is essential because the blanket should remove the high heat flux from the plasma and the volumetric heat generated by neutrons. In this paper, the detailed three dimensional (3D) thermal hydraulic analysis on the whole module of WCCB blanket has been performed by Computational Fluid Dynamics (CFD) method, which is capable of solving conjugate heat transfer between solid structure and fluid. The main results, including temperature field, distribution of mass flow rate and coolant pressure drop, have been calculated simultaneously. These provides beneficial guidance data for the further structural optimization and for the design arrangement of primary and secondary circuit. Under the total heat source of 1.23 MW, the coolant mass flow rate of 5.457 kg/s is required to make coolant water corresponding to the Pressurized Water Reactor (PWR) condition (15.5 MPa, 285 °C–325 °C), generating the total coolant pressure drop (△P) of 0.467 MPa. The results show that the present structural design can make all the materials effectively cooled to the allowable temperature range, except for a few small modifications on the both sides of FW. The main components, including the first wall (FW), cooling plates (CPs), side wall (SWs)&stiffening plates (SPs) and the manifold(1–4), dominate 4.7%/41.7%/13%/40.6% of the total pressure drop, respectively. Additionally, the mass flow rate of each channel has been obtained, showing the peak relative deviation of 3.4% and 2% from the average for the paratactic

  5. Thermal expansion of the cryoprotectant cocktail DP6 combined with synthetic ice modulators in presence and absence of biological tissues.

    Science.gov (United States)

    Eisenberg, David P; Taylor, Michael J; Rabin, Yoed

    2012-10-01

    This study explores physical effects associated with the application of cryopreservation via vitrification using a class of compounds which are defined here as synthetic ice modulators (SIMs). The general classification of SIMs includes molecules that modulate ice nucleation and growth, or possess properties of stabilizing the amorphous state, by virtue of their chemical structure and at concentrations that are not explained on a purely colligative basis. A sub-category of SIMs, referred to in the literature as synthetic ice blockers (SIBs), are compounds that interact directly with ice nuclei or crystals to modify their structure and/or rate of growth. The current study is part of an ongoing effort to characterize thermo-mechanical effects during vitrification, with emphasis on measuring the physical property of thermal expansion-the driving mechanism to thermo-mechanical stress. Materials under investigation are the cryoprotective agent (CPA) cocktail DP6 in combination with one of the following SIMs: 12% polyethylene glycol 400, 6% 1,3 cyclohexanediol, and 6% 2,3 butanediol. Results are presented for the CPA-SIM cocktail in the absence and presence of bovine muscle and goat artery specimens. This study focuses on the upper part of the cryogenic temperature range, where the CPA behaves as a fluid for all practical applications. Results of this study indicate that the addition of SIMs to DP6 allows lower cooling rates to ensure vitrification and extends the range of measurements. It is demonstrated that the combination of SIM with DP6 increases the thermal expansion of the cocktail, with implications for the likelihood of fracture formation-the most dramatic outcome of thermo-mechanical stress. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Development of thermal-hydraulic analysis methodology for multiple modules of water-cooled breeder blanket in fusion DEMO reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon-Woo; Lee, Jeong-Hun [Department of Nuclear Engineering, Seoul National University 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Cho, Hyoung-Kyu, E-mail: chohk@snu.ac.kr [Department of Nuclear Engineering, Seoul National University 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Goon-Cherl [Department of Nuclear Engineering, Seoul National University 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Im, Kihak [National Fusion Research Institute, 169-148, Yuseong-gu, Daejeon 305-806 (Korea, Republic of)

    2016-02-15

    Highlights: • A methodology to simulate the K-DEMO blanket system was proposed. • The results were compared with the CFD, to verify the prediction capability of MARS. • 46 Blankets in a single sector in K-DEMO were simulated using MARS-KS. • Supervisor program was devised to handle each blanket module individually. • The calculation results showed the flow rates, pressure drops, and temperatures. - Abstract: According to the conceptual design of the fusion DEMO reactor proposed by the National Fusion Research Institute of Korea, the water-cooled breeding blanket system incorporates a total of 736 blanket modules. The heat flux and neutron wall loading to each blanket module vary along their poloidal direction, and hence, thermal analysis for at least one blanket sector is required to confirm that the temperature limitations of the materials are satisfied in all the blanket modules. The present paper proposes a methodology of thermal analysis for multiple modules of the blanket system using a nuclear reactor thermal-hydraulic analysis code, MARS-KS. In order to overcome the limitations of the code, caused by the restriction on the number of computational nodes, a supervisor program was devised, which handles each blanket module separately at first, and then corrects the flow rate, considering pressure drops that occur in each module. For a feasibility test of the proposed methodology, 46 blankets in a single sector were simulated; the calculation results of the parameters, such as mass flow, pressure drops, and temperature distribution in the multiple blanket modules showed that the multi-module analysis method can be used for efficient thermal-hydraulic analysis of the fusion DEMO reactor.

  7. Measurement of thermal conductivity of Bi2Te3 nanowire using high-vacuum scanning thermal wave microscopy

    Science.gov (United States)

    Park, Kyungbae; Hwang, Gwangseok; Kim, Hayeong; Kim, Jungwon; Kim, Woochul; Kim, Sungjin; Kwon, Ohmyoung

    2016-02-01

    With the increasing application of nanomaterials in the development of high-efficiency thermoelectric energy conversion materials and electronic devices, the measurement of the intrinsic thermal conductivity of nanomaterials in the form of nanowires and nanofilms has become very important. However, the current widely used methods for measuring thermal conductivity have difficulties in eliminating the influence of interfacial thermal resistance (ITR) during the measurement. In this study, by using high-vacuum scanning thermal wave microscopy (HV-STWM), we propose a quantitative method for measuring the thermal conductivity of nanomaterials. By measuring the local phase lag of high-frequency (>10 kHz) thermal waves passing through a nanomaterial in a high-vacuum environment, HV-STWM eliminates the measurement errors due to ITR and the distortion due to heat transfer through air. By using HV-STWM, we measure the thermal conductivity of a Bi2Te3 nanowire. Because HV-STWM is quantitatively accurate and its specimen preparation is easier than in the thermal bridge method, we believe that HV-STWM will be widely used for measuring the thermal properties of various types of nanomaterials.

  8. Measurement and analysis of thermal conductivity of isotopically controlled silicon layers by time-resolved X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Eon, S.; Frieling, R.; Bracht, H. [Institute for Materials Physics, University of Muenster, 48149 Muenster (Germany); Plech, A. [Institute for Photon Science and Synchrotron Radiation (IPS), 76344 Eggenstein-Leopoldshafen (Germany)

    2016-11-15

    Nanostructuring is considered to be an efficient way to tailor phonon scattering and to reduce the thermal conductivity while keeping good electronic properties. This can be ideally realized by mass modulation of chemical identical elements. In this work, we report measurements of the crossplane thermal conductivity of isotopically modulated {sup 28}Si/{sup 30}Si multilayer structures and of isotopically pure {sup 28}Si layers by means of time-resolved X-ray scattering. Compared to earlier investigations, an improved measurement technique has been applied to determine the cooling behavior of a top gold metal layer after laser excitation with picosecond time resolution until thermal equilibration is established. Detailed analysis of the cooling behavior not only confirms a reduced thermal conductivity of {sup 28}Si/{sup 30}Si multilayer structures compared to natural and isotopically enriched {sup 28}Si layers but also provides evidence of direct laser heating of the Si layer. This and extrinsic effects affecting the cooling behavior of the gold layer are taken into account to determine the thermal conductivity by means of the pump-and-probe measurement technique. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Burn-up measurement in the HTR-module-reactor

    International Nuclear Information System (INIS)

    Gerhards, E.

    1993-05-01

    The burn-up status of spherical HTR-fuel elements is determined by a γ-spectrometric analysis of Cs-137 activity. The γ-spectrum recorded by a semiconductor detector up to now is analyzed by complex mathematical and time-consuming methods. For the operation of the HTR-Module-Reactor, however, a fast evaluation of the burn-up status is necessary. It is shown that this can be ensured by a comparison between the measured spectra and simulation results. Using the computer-program HTROGEN and the program system SPECCALC especially developed for this problem the γ-spectra are evaluated as a function of the burn-up status. The method is applied to results available from the operation of the AVR-reactor. The burn-up status determined with different methods corresponds very well within the limits of accuracy. (orig.)

  10. Characterisation of advanced windows. Determination of thermal properties by measurements

    Energy Technology Data Exchange (ETDEWEB)

    Duer, K.

    2001-04-01

    This report describes work carried out with the aim of facilitating a full energy performance characterisation of advanced windows and glazings by means of measurements. The energy performance of windows and glazings are characterised by two parameters: The thermal transmittance (U-value) and the total solar energy transmittance (g-value) and methods to determine these two parameters by measurements have been investigated. This process has included the improvement of existing equipment and existing measuring methods as well as the development of new measuring equipment and new methods of measuring and data treatment. Measurements of the thermal transmittance of windows and glazings in a guarded hot box have been investigated. The calibration and measuring procedures for determining the U-values of facade windows were analysed and a suggestion for a new calibration and measuring procedure for determining the U-values of roof windows in a guarded hot box was elaborated. The accuracy of the guarded hot box measurements was examined by comparisons to measurements in a hot-plate device and excellent agreement between the results was obtained. Analysis showed that the expected uncertainty in the U-value measurement is about 5% for a specimen with a U-value of 1.75 W/m{sup 2}K. The U-values of three different windows were measured in two separate round robin tests applying two different calibration procedures. The windows U-values where ranging from 1.1 to 2.5 W/m{sup 2}K and all measured results were within the expected uncertainties of the measurements. On the basis of the investigations on hot box measurements a high degree of confidence in the measurement accuracy and the measuring procedure of the guarded hot box at the Department of Buildings and Energy has been obtained. Indoor g-value measurements in a calorimetric test facility (the METSET) mounted in a solar simulator have been investigated and a number of problems regarding these measurements have been

  11. Can Cell to Cell Thermal Runaway Propagation be Prevented in a Li-ion Battery Module?

    Science.gov (United States)

    Jeevarajan, Judith; Lopez, Carlos; Orieukwu, Josephat

    2014-01-01

    Increasing cell spacing decreased adjacent cell damage center dotElectrically connected adjacent cells drained more than physically adjacent cells center dotRadiant barrier prevents propagation when fully installed between BP cells center dotBP cells vent rapidly and expel contents at 100% SOC -Slower vent with flame/smoke at 50% -Thermal runaway event typically occurs at 160 degC center dotLG cells vent but do not expel contents -Thermal runaway event typically occurs at 200 degC center dotSKC LFP modules did not propagate; fuses on negative terminal of cell may provide a benefit in reducing cell to cell damage propagation. New requirement in NASA-Battery Safety Requirements document: JSC 20793 Rev C 5.1.5.1 Requirements - Thermal Runaway Propagation a. For battery designs greater than a 80-Wh energy employing high specific energy cells (greater than 80 watt-hours/kg, for example, lithium-ion chemistries) with catastrophic failure modes, the battery shall be evaluated to ascertain the severity of a worst-case single-cell thermal runaway event and the propensity of the design to demonstrate cell-to-cell propagation in the intended application and environment. NASA has traditionally addressed the threat of thermal runaway incidents in its battery deployments through comprehensive prevention protocols. This prevention-centered approach has included extensive screening for manufacturing defects, as well as robust battery management controls that prevent abuse-induced runaway even in the face of multiple system failures. This focused strategy has made the likelihood of occurrence of such an event highly improbable. b. The evaluation shall include all necessary analysis and test to quantify the severity (consequence) of the event in the intended application and environment as well as to identify design modifications to the battery or the system that could appreciably reduce that severity. In addition to prevention protocols, programs developing battery designs with

  12. Thermal Design and Performance results of the first High-Beta Cryo-module for HIE-ISOLDE at CERN

    CERN Document Server

    Valdarno, L; Leclercq, Y; Parma, V; Vandoni, G; Williams, L

    2015-01-01

    The High Energy and Intensity HIE-ISOLDE is a facility under construction at CERN whose target is ultimately, after the installation of six cryo-modules, to produce radioactive ion beams at 10MeV/u maximum energy in order to significantly expand the nuclear physics programme carried out by REX-ISOLDE. Since thermal control is essential to the performance of the whole cryo-module, a combination of a passive (materials, coatings, and surface finishes) and active (cryogenic loops, heaters) control has been designed to keep the cryostat operating within the allowable thermal budget. A numerical model based on Finite Element has been developed in order to generate a faithful global mapping of temperatures and heat fluxes inside the cryo-module. The numerical model, combined with the experimental results of the first test campaign, will serve as an optimization tool for the future cryo-modules in terms of improvement in the global and specific heat loads management.

  13. Absolute Thermal SST Measurements over the Deepwater Horizon Oil Spill

    Science.gov (United States)

    Good, W. S.; Warden, R.; Kaptchen, P. F.; Finch, T.; Emery, W. J.

    2010-12-01

    Climate monitoring and natural disaster rapid assessment require baseline measurements that can be tracked over time to distinguish anthropogenic versus natural changes to the Earth system. Disasters like the Deepwater Horizon Oil Spill require constant monitoring to assess the potential environmental and economic impacts. Absolute calibration and validation of Earth-observing sensors is needed to allow for comparison of temporally separated data sets and provide accurate information to policy makers. The Ball Experimental Sea Surface Temperature (BESST) radiometer was designed and built by Ball Aerospace to provide a well calibrated measure of sea surface temperature (SST) from an unmanned aerial system (UAS). Currently, emissive skin SST observed by satellite infrared radiometers is validated by shipborne instruments that are expensive to deploy and can only take a few data samples along the ship track to overlap within a single satellite pixel. Implementation on a UAS will allow BESST to map the full footprint of a satellite pixel and perform averaging to remove any local variability due to the difference in footprint size of the instruments. It also enables the capability to study this sub-pixel variability to determine if smaller scale effects need to be accounted for in models to improve forecasting of ocean events. In addition to satellite sensor validation, BESST can distinguish meter scale variations in SST which could be used to remotely monitor and assess thermal pollution in rivers and coastal areas as well as study diurnal and seasonal changes to bodies of water that impact the ocean ecosystem. BESST was recently deployed on a conventional Twin Otter airplane for measurements over the Gulf of Mexico to access the thermal properties of the ocean surface being affected by the oil spill. Results of these measurements will be presented along with ancillary sensor data used to eliminate false signals including UV and Synthetic Aperture Radar (SAR

  14. Thermal decomposition of hydroxylamine: Isoperibolic calorimetric measurements at different conditions

    International Nuclear Information System (INIS)

    Adamopoulou, Theodora; Papadaki, Maria I.; Kounalakis, Manolis; Vazquez-Carreto, Victor; Pineda-Solano, Alba; Wang, Qingsheng; Mannan, M.Sam

    2013-01-01

    Highlights: • Hydroxylamine thermal decomposition enthalpy was measured using larger quantities. • The rate at which heat is evolved depends on hydroxylamine concentration. • Decomposition heat is strongly affected by the conditions and the selected baseline. • The need for enthalpy measurements using a larger reactant mass is pinpointed. • Hydroxylamine decomposition in the presence of argon is much faster than in air. -- Abstract: Thermal decomposition of hydroxylamine, NH 2 OH, was responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting its decomposition are not being understood. In this work, the global enthalpy of hydroxylamine decomposition has been measured in the temperature range of 130–150 °C employing isoperibolic calorimetry. Measurements were performed in a metal reactor, employing 30–80 ml solutions containing 1.4–20 g of pure hydroxylamine (2.8–40 g of the supplied reagent). The measurements showed that increased concentration or temperature, results in higher global enthalpies of reaction per unit mass of reactant. At 150 °C, specific enthalpies as high as 8 kJ per gram of hydroxylamine were measured, although in general they were in the range of 3−5 kJ g −1 . The accurate measurement of the generated heat was proven to be a cumbersome task as (a) it is difficult to identify the end of decomposition, which after a fast initial stage, proceeds very slowly, especially at lower temperatures and (b) the environment of gases affects the reaction rate

  15. Thermal decomposition of hydroxylamine: Isoperibolic calorimetric measurements at different conditions

    Energy Technology Data Exchange (ETDEWEB)

    Adamopoulou, Theodora [Department of Environmental and Natural Resources Management, University of Western Greece (formerly of University of Ioannina), Seferi 2, Agrinio GR30100 (Greece); Papadaki, Maria I., E-mail: mpapadak@cc.uoi.gr [Department of Environmental and Natural Resources Management, University of Western Greece (formerly of University of Ioannina), Seferi 2, Agrinio GR30100 (Greece); Kounalakis, Manolis [Department of Environmental and Natural Resources Management, University of Western Greece (formerly of University of Ioannina), Seferi 2, Agrinio GR30100 (Greece); Vazquez-Carreto, Victor; Pineda-Solano, Alba [Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States); Wang, Qingsheng [Department of Fire Protection and Safety and Department of Chemical Engineering, Oklahoma State University, 494 Cordell South, Stillwater, OK 74078 (United States); Mannan, M.Sam [Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States)

    2013-06-15

    Highlights: • Hydroxylamine thermal decomposition enthalpy was measured using larger quantities. • The rate at which heat is evolved depends on hydroxylamine concentration. • Decomposition heat is strongly affected by the conditions and the selected baseline. • The need for enthalpy measurements using a larger reactant mass is pinpointed. • Hydroxylamine decomposition in the presence of argon is much faster than in air. -- Abstract: Thermal decomposition of hydroxylamine, NH{sub 2}OH, was responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting its decomposition are not being understood. In this work, the global enthalpy of hydroxylamine decomposition has been measured in the temperature range of 130–150 °C employing isoperibolic calorimetry. Measurements were performed in a metal reactor, employing 30–80 ml solutions containing 1.4–20 g of pure hydroxylamine (2.8–40 g of the supplied reagent). The measurements showed that increased concentration or temperature, results in higher global enthalpies of reaction per unit mass of reactant. At 150 °C, specific enthalpies as high as 8 kJ per gram of hydroxylamine were measured, although in general they were in the range of 3−5 kJ g{sup −1}. The accurate measurement of the generated heat was proven to be a cumbersome task as (a) it is difficult to identify the end of decomposition, which after a fast initial stage, proceeds very slowly, especially at lower temperatures and (b) the environment of gases affects the reaction rate.

  16. Advances in estimation technology of thermal conductivity of irradiated fuels (1). Application of a thermal microscope to measure the thermal conductivity of the second phases in irradiated pellets

    International Nuclear Information System (INIS)

    Uno, Masayoshi; Murakami, Yukihiro

    2011-01-01

    CeO 2 sample as a surrogate for fuel and BaCeO 3 and BaMoO 4 samples as surrogates for the second phases, which have a lower thermal conductivity than the fuel matrix, were made. The thermal conductivity of these samples was measured by a thermal microscope. In this method, the thermal conductivity of a small region (e.g. 20 μm x 20 μm) of the sample can be measured. The valid thermal conductivity values for all the samples were obtained and the conditions of sample surface preparation and the thermal microscope measurement were found out. The thermal conductivity of a CeO 2 composite pellet which had the BaCeO 3 or BaMoO 4 second phase layer was also estimated. (author)

  17. Hydro-Thermal Fatigue Resistance Measurements on Polymer Interfaces

    Science.gov (United States)

    Gurumurthy, Charan K.; Kramer, Edward J.; Hui, Chung-Yuen

    1998-03-01

    We have developed a new technique based on a fiber optic displacement sensor for rapid determination of hydro-thermal fatigue crack growth rate per cycle (da/dN) of an epoxy/polyimide interface used in flip chip attach microelectronic assembly. The sample is prepared as a trilayered cantilever beam by capillary flow of the epoxy underfill over a polyimide coated metallic beam. During hydro-thermal cycling the crack growth along the interface (from the free end) changes the displacement of this end of the beam and we measure the free end displacement at the lowest temperature in each hydro-thermal cycle. The change in beam displacement is then converted into crack growth rate (da/dN). da/dN depends on the maximum change in the strain energy release rate of the crack and the phase angle in each cycle. The relation between da/dN and maximum strain energy release rate characterizes the fatigue crack growth resistance of the interface. We have developed and used a simple model anhydride cured and a commercially available PMDA/ODA passivation for this study.

  18. Compact electro-thermal modeling of a SiC MOSFET power module under short-circuit conditions

    DEFF Research Database (Denmark)

    Ceccarelli, Lorenzo; Reigosa, Paula Diaz; Bahman, Amir Sajjad

    2017-01-01

    A novel physics-based, electro-thermal model which is capable of estimating accurately the short-circuit behavior and thermal instabilities of silicon carbide MOSFET multi-chip power modules is proposed in this paper. The model has been implemented in PSpice and describes the internal structure.......2 kV breakdown voltage and about 300 A rated current. The short-circuit behavior of the module is investigated experimentally through a non-destructive test setup and the model is validated. The estimation of overcurrent and temperature distribution among the chips can provide useful information...

  19. Using Paraffin PCM to Make Optical Communication Type of Payloads Thermally Self-Sufficient for Operation in Orion Crew Module

    Science.gov (United States)

    Choi, Michael K.

    2016-01-01

    An innovative concept of using paraffin phase change material with a melting point of 28 C to make Optical Communication type of payload thermally self-sufficient for operation in the Orion Crew Module is presented. It stores the waste heat of the payload and permits it to operate for about one hour by maintaining its temperature within the maximum operating limit. It overcomes the problem of relying on the availability of cold plate heat sink in the Orion Crew Module.

  20. Thermal Efficiency of Power Module “Boiler with Solar Collectors as Additional Heat Source” For Combined Heat Supply System

    Directory of Open Access Journals (Sweden)

    Denysova A.E.

    2015-04-01

    Full Text Available The purpose of work is to increase the efficiency of the combined heat supply system with solar collectors as additional thermal generators. In order to optimize the parameters of combined heat supply system the mathematical modeling of thermal processes in multi module solar collectors as additional thermal generators for preheating of the water for boiler have been done. The method of calculation of multi-module solar collectors working with forced circulation for various configurations of hydraulic connection of solar collector modules as the new result of our work have been proposed. The results of numerical simulation of thermal efficiency of solar heat source for boiler of combined heat supply system with the account of design features of the circuit; regime parameters of thermal generators that allow establishing rational conditions of its functioning have been worked out. The conditions of functioning that provide required temperature of heat carrier incoming to boiler and value of flow rate at which the slippage of heat carrier is not possible for different hydraulic circuits of solar modules have been established.

  1. Modelling measurement microphones using BEM with visco-thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2012-01-01

    For many decades, models that can explain the behaviour of measurement condenser microphones have been proposed in the literature. These devices have an apparently simple working principle, a charged capacitor whose charge varies when one of its electrodes, the diaphragm, moves as a result of sound...... waves. However, measurement microphones must be manufactured very carefully due to their sensitivity to small changes of their physical parameters. There are different elements in a microphone, the diaphragm, the gap behind it, a back cavity, a vent for pressure equalization and an external medium. All...... visco-thermal losses is used to model measurement condenser microphones. The models presented are fully coupled and include a FEM model of the diaphragm. The behaviour of the acoustic variables in the gap and the effect of the pressure equalization vent are discussed, as well as the practical difficulty...

  2. Innovation of fission gas release and thermal conductivity measurement methods

    International Nuclear Information System (INIS)

    Van der Meer, K.; Soboler, V.

    1998-01-01

    This presentation described two innovative measurement methods being currently developed at SCK-CEN in order to support the modeling of fuel performance. The first one is an acoustic method to measure the fission gas release in a fuel rod in a non destructive way. The total rod pressure is determined by generating a heat pulse causing a pressure wave that propagates through the gas to an ultrasound transducer. The final pulse width being proportional to the pressure, the latter can thus be determined. The measurement of the acoustic resonance frequency at fixed temperatures enables the distinction between different gas components. The second method is a non-stationary technique to investigate the thermal properties of the fuel rod, like thermal conductivity, diffusivity and heat capacity. These properties are derived from the amplitude and the phase shift of the fuel centre temperature response induced by a periodic temperature variation. These methods did not reveal any physical limitations for the practical applicability. Furthermore, they are rather simple. Preliminary investigations have proven both methods to be more accurate than techniques usually utilized. (author)

  3. Measurement of Thermal Dependencies of PBG Fiber Properties

    International Nuclear Information System (INIS)

    Laouar, Rachik

    2011-01-01

    Photonic crystal fibers (PCFs) represent a class of optical fibers which have a wide spectrum of applications in the telecom and sensing industries. Currently, the Advanced Accelerator Research Department at SLAC is developing photonic bandgap particle accelerators, which are photonic crystal structures with a central defect used to accelerate electrons and achieve high longitudinal electric fields. Extremely compact and less costly than the traditional accelerators, these structures can support higher accelerating gradients and will open a new era in high energy physics as well as other fields of science. Based on direct laser acceleration in dielectric materials, the so called photonic band gap accelerators will benefit from mature laser and semiconductor industries. One of the key elements to direct laser acceleration in hollow core PCFs, is maintaining thermal and structural stability. Previous simulations demonstrate that accelerating modes are sensitive to the geometry of the defect region and the variations in the effective index. Unlike the telecom modes (for which over 95% of the energy propagates in the hollow core) most of the power of these modes is located in the glass at the periphery of the central hole which has a higher thermal constant than air (γ SiO# sub 2# = 1.19 x 10 -6 1/K, γ air = -9 x 10 -7 1/K with γ = dn/dT). To fully control laser driven acceleration, we need to evaluate the thermal and structural consequences of such modes on the PCFs. We are conducting series of interferometric tests to quantify the dependencies of the HC-633-02 (NKT Photonics) propagation constant (k z ) on temperature, vibration amplitude, stress and electric field strength. In this paper we will present the theoretical principles characterizing the thermal behavior of a PCF, the measurements realized for the fundamental telecom mode (TE 00 ), and the experimental demonstration of TM-like mode propagation in the HC-633-02 fiber.

  4. Measuring energy expenditure in sports by thermal video analysis

    DEFF Research Database (Denmark)

    Gade, Rikke; Larsen, Ryan Godsk; Moeslund, Thomas B.

    2017-01-01

    Estimation of human energy expenditure in sports and exercise contributes to performance analyses and tracking of physical activity levels. The focus of this work is to develop a video-based method for estimation of energy expenditure in athletes. We propose a method using thermal video analysis...... to automatically extract the cyclic motion pattern, in walking and running represented as steps, and analyse the frequency. Experiments are performed with one subject in two different tests, each at 5, 8, 10, and 12 km/h. The results of our proposed video-based method is compared to concurrent measurements...

  5. High-throughput heterodyne thermoreflectance: Application to thermal conductivity measurements of a Fe-Si-Ge thin film alloy library

    Science.gov (United States)

    d'Acremont, Quentin; Pernot, Gilles; Rampnoux, Jean-Michel; Furlan, Andrej; Lacroix, David; Ludwig, Alfred; Dilhaire, Stefan

    2017-07-01

    A High-Throughput Time-Domain ThermoReflectance (HT-TDTR) technique was developed to perform fast thermal conductivity measurements with minimum user actions required. This new setup is based on a heterodyne picosecond thermoreflectance system. The use of two different laser oscillators has been proven to reduce the acquisition time by two orders of magnitude and avoid the experimental artefacts usually induced by moving the elements present in TDTR systems. An amplitude modulation associated to a lock-in detection scheme is included to maintain a high sensitivity to thermal properties. We demonstrate the capabilities of the HT-TDTR setup to perform high-throughput thermal analysis by mapping thermal conductivity and interface resistances of a ternary thin film silicide library FexSiyGe100-x-y (20 deposited by wedge-type multi-layer method on a 100 mm diameter sapphire wafer offering more than 300 analysis areas of different ternary alloy compositions.

  6. Reexamination of basal plane thermal conductivity of suspended graphene samples measured by electro-thermal micro-bridge methods

    Directory of Open Access Journals (Sweden)

    Insun Jo

    2015-05-01

    Full Text Available Thermal transport in suspended graphene samples has been measured in prior works and this work with the use of a suspended electro-thermal micro-bridge method. These measurement results are analyzed here to evaluate and eliminate the errors caused by the extrinsic thermal contact resistance. It is noted that the room-temperature thermal resistance measured in a recent work increases linearly with the suspended length of the single-layer graphene samples synthesized by chemical vapor deposition (CVD, and that such a feature does not reveal the failure of Fourier’s law despite the increase in the reported apparent thermal conductivity with length. The re-analyzed apparent thermal conductivity of a single-layer CVD graphene sample reaches about 1680 ± 180 W m−1 K−1 at room temperature, which is close to the highest value reported for highly oriented pyrolytic graphite. In comparison, the apparent thermal conductivity values measured for two suspended exfoliated bi-layer graphene samples are about 880 ± 60 and 730 ± 60 Wm−1K−1 at room temperature, and approach that of the natural graphite source above room temperature. However, the low-temperature thermal conductivities of these suspended graphene samples are still considerably lower than the graphite values, with the peak thermal conductivities shifted to much higher temperatures. Analysis of the thermal conductivity data reveals that the low temperature behavior is dominated by phonon scattering by polymer residue instead of by the lateral boundary.

  7. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    OpenAIRE

    Xu, Shi-Zhou; He, Feng-You

    2016-01-01

    In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single pe...

  8. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice.

    Science.gov (United States)

    Chen, Yong; Boettger, Michael K; Reif, Andreas; Schmitt, Angelika; Uçeyler, Nurcan; Sommer, Claudia

    2010-03-02

    Although it has been largely demonstrated that nitric oxide synthase (NOS), a key enzyme for nitric oxide (NO) production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Intraperitoneal (i.p.) pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor), aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor), L-N(G)-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor), but not L-N(5)-(1-iminoethyl)-ornithine (L-NIO, a selective endothelial NOS inhibitor), significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl.) injection of complete Freund's adjuvant (CFA). Real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1beta), and interleukin-10 (IL-10) gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1beta. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO) mice had lower gene expression of TNF, IL-1beta, and IL-10 following CFA, overall corroborating the inhibitor data. These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  9. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice

    Directory of Open Access Journals (Sweden)

    Üçeyler Nurcan

    2010-03-01

    Full Text Available Abstract Background Although it has been largely demonstrated that nitric oxide synthase (NOS, a key enzyme for nitric oxide (NO production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Results Intraperitoneal (i.p. pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor, aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor, L-N(G-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor, but not L-N(5-(1-iminoethyl-ornithine (L-NIO, a selective endothelial NOS inhibitor, significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl. injection of complete Freund's adjuvant (CFA. Real-time reverse transcription-polymerase chain reaction (RT-PCR revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF, interleukin-1 beta (IL-1β, and interleukin-10 (IL-10 gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1β. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO mice had lower gene expression of TNF, IL-1β, and IL-10 following CFA, overall corroborating the inhibitor data. Conclusion These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  10. Alignment Methods Developed for the Validation of the Thermal and Mechanical Behaviour of the Two Beam Test Modules for the CLIC Project

    CERN Document Server

    Mainaud Durand, Helene; Sosin, Mateusz; Rude, Vivien

    2014-01-01

    CLIC project will consist of more than 20 000 two meters long modules. A test setup made of three modules is being built at CERN to validate the assembly and integration of all components and technical systems and to validate the short range strategy of pre-alignment. The test setup has been installed in a room equipped with a sophisticated system of ventilation able to reproduce the environmental conditions of the CLIC tunnel. Some of the components have been equipped with electrical heaters to simulate the power dissipation, combined with a water cooling system integrated in the RF components. Using these installations, to have a better understanding of the thermal and mechanical behaviour of a module under different operation modes, machine cycles have been simulated; the misalignment of the components and their supports has been observed. This paper describes the measurements methods developed for such a project and the results obtained.

  11. A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-11-01

    This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  12. Thermal and chemical denaturation of Bacillus circulans xylanase: A biophysical chemistry laboratory module.

    Science.gov (United States)

    Raabe, Richard; Gentile, Lisa

    2008-11-01

    A number of institutions have been, or are in the process of, modifying their biochemistry major to include some emphasis on the quantitative physical chemistry of biomolecules. Sometimes this is done as a replacement for part for the entire physical chemistry requirement, while at other institutions this is incorporated as a component into the traditional two-semester biochemistry series. The latter is the model used for biochemistry and molecular biology majors at the University of Richmond, whose second semester of biochemistry is a course entitled Proteins: Structure, Function, and Biophysics. What is described herein is a protein thermodynamics laboratory module, using the protein Bacillus circulans xylanase, which reinforces many lecture concepts, including: (i) the denatured (D) state ensemble of a protein can be different, depending on how it was populated; (ii) intermediate states may be detected by some spectroscopic techniques but not by others; (iii) the use and assumptions of the van't Hoff approach to calculate ΔH(o) , ΔS(o) , and ΔG(o) (T) for thermal protein unfolding transitions; and (iv) the use and assumptions of an approach that allows determination of the Gibb's free energy of a protein unfolding transition based on the linear dependence of ΔG(o) on the concentration of denaturant used. This module also requires students to design their own experimental protocols and spend time in the primary literature, both important parts of an upper division lab. Copyright © 2008 International Union of Biochemistry and Molecular Biology, Inc.

  13. Contribution of modulated DSc to study the thermal behaviour of PET films drawn in hot water

    International Nuclear Information System (INIS)

    Zumalian, Abubaker

    2003-01-01

    PET films uni-axially drawn in hot water are studied by means of conventional DSc and modulated DSc. The glass transition is studied by modulated DSc which allows access to the values of the glass transition temperature T g and the variations of δ C p = C p 1-C p g (difference between thermal capacity in the liquid-like and glassy states at T = T g ). Variations of T g with the water content (which act as plasticizer) and with the drawing (which rigidifies the amorphous phase) are discussed in regard to the structure engaged in these materials. The variations of δ C p are also interpreted with the help of a three phase model and a strong-fragile glass former liquid concept. We show that the fragility of the medium increases by the conjugated effects of deformation and water as soon as a strain induced crystalline phase is obtained, and it decreases drastically when the rigid amorphous phase occurs. (author)

  14. Thermal diffusivity measurement of erythritol and numerical analysis of heat storage performance on a fin-type heat exchanger

    International Nuclear Information System (INIS)

    Zamengo, Massimiliano; Funada, Tomohiro; Morikawa, Junko

    2017-01-01

    Highlights: • Thermal diffusivity of Erythritol was measured by temperature wave method. • Thermal diffusivity was measured in function of temperature and during phase change. • Database of temperature-dependent thermal properties is used for numerical analysis. • Heat transfer and heat storage were analyzed in a fin-type heat exchanger. • Use of temperature-dependent properties in calculations lead to longer melting time. - Abstract: Temperature dependency of thermal diffusivity of erythritol was measured by temperature wave analysis (TWA) method. This modulating technique allowed measuring thermal diffusivity continuously, even during the phase transition solid-liquid. Together with specific heat capacity and specific enthalpy measured by differential scanning calorimetry, the values of measured properties were utilized in a bi-dimensional numerical model for analysis of heat transfer and heat storage performance. The geometry of the model is representative of a cross section of a fin-type heat exchanger, in which erythritol is filling the interspaces between fins. Time-dependent temperature change and heat storage performance were analyzed by considering the variation of thermophysical properties as a function of temperature. The numerical method can be utilized for a fast parametric analysis of heat transfer and heat storage performance into heat storage systems of phase-change materials and composites.

  15. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

    Science.gov (United States)

    Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-01-01

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to –40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments. PMID:25993037

  16. Amplified spontaneous emission measurements on the Aurora large aperture module

    International Nuclear Information System (INIS)

    Oertel, J.A.; Czuchlewski, S.J.; Leland, W.T.; Turner, T.P.

    1990-01-01

    The large aperture module (LAM) of the Aurora KrF laser can be used to address a number of issues that relate to the scaling of KrF amplifiers to larger ICF systems. Perhaps foremost among these are the possible effects of amplified spontaneous emission (ASE) on laser performance. To assess this problem a 3-D computer code has been developed to model these ASE effects. The code uses an iterative procedure to arrive at a self-consistent steady state solution to the 3-D distribution of coherent and incoherent fluxes within the amplifier. Two-pass energy extraction, wall reflectivity, and nonuniform excitation are included in the model. The authors previously reported the effects of ASE on the small signal gains measured in the 1- x 1- x 2-m 3 LAM. The code also makes quantitative predictions of the ASE that should be generated in the amplifier. This paper indicates the radiance expected for a medium of uniform gain in terms of the (g - ν)L product and the parameter g/a. The quantity (g - ν)L is the product of the net gain and the path length along the direction of observation. The present experiments compare values of ASE measured at various locations around the LAM with the code predictions. The impact of ASE on amplifier output, is also discussed

  17. Measurement of the thermal Sunyaev-Zel'dovich effect around cosmic voids

    Science.gov (United States)

    Alonso, David; Hill, J. Colin; Hložek, Renée; Spergel, David N.

    2018-03-01

    We stack maps of the thermal Sunyaev-Zel'dovich effect produced by the Planck Collaboration around the centers of cosmic voids defined by the distribution of galaxies in the CMASS sample of the Baryon Oscillation Spectroscopic Survey, scaled by the void effective radii. We report a first detection of the associated cross-correlation at the 3.4 σ level: voids are under-pressured relative to the cosmic mean. We compare the measured Compton-y profile around voids with a model based solely on the spatial modulation of halo abundance with environmental density. The amplitude of the detected signal is marginally lower than predicted by an overall amplitude αv=0.67 ±0.2 . We discuss the possible interpretations of this measurement in terms of modeling uncertainties, excess pressure in low-mass halos, or nonlocal heating mechanisms.

  18. Thermal neutron cross section measurements for technetium-99

    International Nuclear Information System (INIS)

    Yates, M.A.; Schroeder, N.C.; Fowler, M.M.

    1993-01-01

    Technetium, because of its long half-like (213,000 years) and ability to migrate in the environment, is a primary contributor to the long-term radioactivity related risk associated with geologic nuclear waste disposal. One proposal for converting technetium to an environmentally benign element investigating transmutation with an accelerator-based system, (i.e., Accelerator Transmutation of Waste, ATW). Planning for efficient processing of technetium through the transmuter will require knowledge of the thermal neutron cross section for the 99 Tc (n,γ) 100 Tc reaction. The authors have recently remeasured this cross section. Weighed aliquots (19-205 μg) of a NIST traceable 99 Tc standard were irradiated for 30-150 sec using the pneumatic open-quotes rabbitclose quotes system of LANL's Omega West Reactor. The two gamma rays from the 15.7-sec half-life product were measured immediately after irradiation on a high-resolution Ge detector. Thermal fluxes were measured using gold foils and Cd wrapped gold foils. The observation cross section is 19 ± 1 b. This agrees well with the 1977 value but has half the uncertainty

  19. Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

    International Nuclear Information System (INIS)

    Zhang Yue-Fei; Wang Li; Wei Bin; Ji Yuan; Han Xiao-Dong; Zhang Ze; Heiderhoff, R.; Geinzer, A. K.; Balk, L. J.

    2012-01-01

    The local thermal conductivity of polycrystalline aluminum nitride (AlN) ceramics is measured and imaged by using a scanning thermal microscope (SThM) and complementary scanning electron microscope (SEM) based techniques at room temperature. The quantitative thermal conductivity for the AlN sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3ω method. A thermal conductivity of 308 W/m·K within grains corresponding to that of high-purity single crystal AlN is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy. (condensed matter: structural, mechanical, and thermal properties)

  20. Evaluation of thermal performance of all-GaN power module in parallel operation

    International Nuclear Information System (INIS)

    Chou, Po-Chien; Cheng, Stone; Chen, Szu-Hao

    2014-01-01

    This work presents an extensive thermal characterization of a single discrete GaN high-electron-mobility transistor (HEMT) device when operated in parallel at temperatures of 25 °C–175 °C. The maximum drain current (I D max ), on-resistance (R ON ), pinch-off voltage (V P ) and peak transconductance (g m ) at various chamber temperatures are measured and correlations among these parameters studied. Understanding the dependence of key transistor parameters on temperature is crucial to inhibiting the generation of hot spots and the equalization of currents in the parallel operation of HEMTs. A detailed analysis of the current imbalance between two parallel HEMT cells and its consequential effect on the junction temperature are also presented. The results from variations in the characteristics of the parallel-connected devices further verify that the thermal stability and switching behavior of these cells are balanced. Two parallel HEMT cells are operated at a safe working distance from thermal runaway to prevent destruction of the hottest cell. - Highlights: • This work reveals the sorting process of GaN devices for parallel operation. • The variations of I D max , R ON , V P , and g m with temperature are established. • The temperature-dependence parameters are crucial to prevent hot spots generation. • Safe working operation prevents thermal runaway and hottest cell destruction

  1. Thermal conductivity and diffusivity of biomaterials measured with self-heated thermistors

    Science.gov (United States)

    Valvano, J. W.; Cochran, J. R.; Diller, K. R.

    1985-05-01

    This paper presents an experimental method to measure the thermal conductivity and thermal diffusivity of biomaterials. Self-heated thermistor probes, inserted into the tissue of interest, are used to deliver heat as well as to monitor the rate of heat removal. An empirical calibration procedure allows accurate thermal-property measurements over a wide range of tissue temperatures. Operation of the instrument in three media with known thermal properties shows the uncertainty of measurements to be about 2%. The reproducibility is 0.5% for the thermal-conductivity measurements and 2% for the thermal-diffusivity measurements. Thermal properties were measured in dog, pig, rabbit, and human tissues. The tissues included kidney, spleen, liver, brain, heart, lung, pancreas, colon cancer, and breast cancer. Thermal properties were measured for 65 separate tissue samples at 3, 10, 17, 23, 30, 37, and 45°C. The results show that the temperature coefficient of biomaterials approximates that of water.

  2. Solar intensity measurement using a thermoelectric module; experimental study and mathematical modeling

    International Nuclear Information System (INIS)

    Rahbar, Nader; Asadi, Amin

    2016-01-01

    Highlights: • Solar intensity could be explained as a linear function of voltage and ambient temperature. • The maximum output voltage is approximately 120 mV which was occurred in midday. • The average value of the heat-sink thermal resistance could be measured with this device. • The average values of total heat transfer coefficients could be measured with this device. • Two correlations were proposed to predict the solar intensity with the accuracy of 10%. - Abstract: The present study is intended to design, manufacture, and modeling an inexpensive pyranometer using a thermoelectric module. The governing equations relating the solar intensity, output voltage, and ambient temperature have been derived by applying the mathematical and thermodynamic models. According to the thermodynamics modeling, the output voltage is a function of solar intensity, ambient temperature, internal parameters of thermoelectric module, convection and radiation coefficients, and geometrical characteristics of the setup. Moreover, the solar intensity can be considered as a linear function of voltage and ambient temperature within an acceptable range of accuracy. The experiments have been carried out on a typical winter day under climatic conditions of Semnan (35°33′N, 53°23′E), Iran. The results also indicated that the output voltage is dependent on the solar intensity and its maximum value was 120 mV. Finally, based on the experimental results, two correlations, with the accuracy of 10%, have been proposed to predict the solar intensity as a function of output voltage and ambient temperature. The average values of total heat transfer coefficient and thermal resistance of the heat-sink have been also calculated according to the thermodynamic modeling and experimental results.

  3. Thermal decomposition of hydroxylamine: isoperibolic calorimetric measurements at different conditions.

    Science.gov (United States)

    Adamopoulou, Theodora; Papadaki, Maria I; Kounalakis, Manolis; Vazquez-Carreto, Victor; Pineda-Solano, Alba; Wang, Qingsheng; Mannan, M Sam

    2013-06-15

    Thermal decomposition of hydroxylamine, NH2OH, was responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting its decomposition are not being understood. In this work, the global enthalpy of hydroxylamine decomposition has been measured in the temperature range of 130-150 °C employing isoperibolic calorimetry. Measurements were performed in a metal reactor, employing 30-80 ml solutions containing 1.4-20 g of pure hydroxylamine (2.8-40 g of the supplied reagent). The measurements showed that increased concentration or temperature, results in higher global enthalpies of reaction per unit mass of reactant. At 150 °C, specific enthalpies as high as 8 kJ per gram of hydroxylamine were measured, although in general they were in the range of 3-5 kJ g(-1). The accurate measurement of the generated heat was proven to be a cumbersome task as (a) it is difficult to identify the end of decomposition, which after a fast initial stage, proceeds very slowly, especially at lower temperatures and (b) the environment of gases affects the reaction rate. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Study on the Thermal Resistance of Multi-chip Module High Power LED Packaging Heat Dissipation System

    Directory of Open Access Journals (Sweden)

    Kailin Pan

    2014-10-01

    Full Text Available Thermal resistance is a key technical index which indicates the thermal management of multi-chip module high power LED (MCM-LED packaging heat dissipation system. In this paper, the prototype structure of MCM-LED packaging heat dissipation system is proposed to study the reliable thermal resistance calculation method. In order to analyze the total thermal resistance of the MCM-LED packaging heat dissipation system, three kinds of thermal resistance calculation method including theoretical calculation, experimental testing and finite element simulation are developed respectively. Firstly, based on the thermal resistance network model and the principle of steady state heat transfer, the theoretical value of total thermal resistance is 6.111 K/W through sum of the thermal resistance of every material layer in the major direction of heat flow. Secondly, the thermal resistance experiment is carried out by T3Ster to obtain the experimental result of total thermal resistance, and the value is 6.729 K/W. Thirdly, a three-dimensional finite element model of MCM-LED packaging heat dissipation system is established, and the junction temperature experiment is also performed to calculated the finite element simulated result of total thermal resistance, the value is 6.99 K/W. Finally, by comparing the error of all the three kinds of result, the error of total thermal resistance between the theoretical value and experimental result is 9.2 %, and the error of total thermal resistance between the experimental result and finite element simulation is only about -3.9 %, meanwhile, the main reason of each error is discussed respectively.

  5. Magneto-optically modulated CH/sub 3/OH laser For faraday rotation measurements in tokamaks

    International Nuclear Information System (INIS)

    Mansfield, D.K.; Johnson, L.C.

    1981-01-01

    Distortion-free intracavity polarization modulation of an optically pumped CH/sub 3/OH laser is shown to be viable. The possible use of this modulation technique to make a multichannel Faraday rotation measurement on a Tokamak device is discussed. In addition, the CdTe Faraday modulator employed in this study is shown to have an anomalously large Verdet constant. 12 refs

  6. A magneto-optically modulated CH3OH laser for Faraday rotation measurements in tokamaks

    International Nuclear Information System (INIS)

    Mansfield, D.K.; Johnson, L.C.

    1981-01-01

    Distortion-free intracavity polarization modulation of an optically pumped CH3OH laser is shown to be viable. The possible use of this modulation technique to make a multichannel Faraday rotation measurement on a tokamak device is discussed. In addition, the CdTe Faraday modulator employed in this study is shown to have an anomalously large Verdet constant

  7. Measurements of the thermal radiative properties of liquid uranium

    International Nuclear Information System (INIS)

    Havstad, M.A.; McLean, W. II; Self, S.A.

    1992-07-01

    Measurements of the thermal radiative properties of liquid uranium have been made using an instrument with two optical systems, one for measuring the complex index of refraction by ellipsometry, the other for measuring the normal spectral emissivity by direct comparison to an integral blackbody cavity. The measurements cover the wavelength range 0.4 to 10 μm with sample temperatures between 940 and 1630 K. Two 5keV ion sputter guns and an Auger spectrometer produce and verify, in-situ, atomically pure sample surfaces. Good agreement between the two methods is observed for the normal spectral emissivity, which varies with wavelength in a manner typical of transition metals. The two components of the complex index of refraction, the index of refraction and the extinction coefficient, increase with wavelength, from ∼3 at 0.4 μm to -20 at 9.5 μm. Both components of polarized reflectivity are shown for visible to infrared wavelengths

  8. Security camera resolution measurements: Horizontal TV lines versus modulation transfer function measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Birch, Gabriel Carisle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Griffin, John Clark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    The horizontal television lines (HTVL) metric has been the primary quantity used by division 6000 related to camera resolution for high consequence security systems. This document shows HTVL measurements are fundamen- tally insufficient as a metric to determine camera resolution, and propose a quantitative, standards based methodology by measuring the camera system modulation transfer function (MTF), the most common and accepted metric of res- olution in the optical science community. Because HTVL calculations are easily misinterpreted or poorly defined, we present several scenarios in which HTVL is frequently reported, and discuss their problems. The MTF metric is discussed, and scenarios are presented with calculations showing the application of such a metric.

  9. Nuclear Engineering Computer Modules, Thermal-Hydraulics, TH-3: High Temperature Gas Cooled Reactor Thermal-Hydraulics.

    Science.gov (United States)

    Reihman, Thomas C.

    This learning module is concerned with the temperature field, the heat transfer rates, and the coolant pressure drop in typical high temperature gas-cooled reactor (HTGR) fuel assemblies. As in all of the modules of this series, emphasis is placed on developing the theory and demonstrating its use with a simplified model. The heart of the module…

  10. Simultaneous measurement of thermal conductivity, thermal diffusivity and prediction of effective thermal conductivity of porous consolidated igneous rocks at room temperature

    International Nuclear Information System (INIS)

    Aurangzeb; Ali, Zulqurnain; Gurmani, Samia Faiz; Maqsood, Asghari

    2006-01-01

    Thermal conductivity, thermal diffusivity and heat capacity per unit volume of porous consolidated igneous rocks have been measured, simultaneously by Gustafsson's probe at room temperature and normal pressure using air as saturant. Data are presented for eleven samples of dunite, ranging in porosity from 0.130 to 0.665% by volume, taken from Chillas near Gilgit, Pakistan. The porosity and density parameters have been measured using American Society of Testing and Materials (ASTM) standards at ambient conditions. The mineral composition of samples has been analysed from their thin sections (petrography). An empirical model to predict the thermal conductivity of porous consolidated igneous rocks is also proposed. The thermal conductivities are predicted by some of the existing models along with the proposed one. It is observed that the values of effective thermal conductivity predicted by the proposed model are in agreement with the experimental thermal conductivity data within 6%

  11. Heterodyne technique for measuring the amplitude and phase transfer functions of an optical modulator

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2002-01-01

    In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From the measure...... the measurements we derive the small-signal alpha-parameter and the time-dependent chirp for different operation conditions.......In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From...

  12. Transient plane source (tps) sensors for simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and conductors

    Science.gov (United States)

    Maqsood, Asghari; Anis-ur-Rehman, M.

    2013-12-01

    Thermal conductivity and thermal diffusivity are two important physical properties for designing any food engineering processes1. The knowledge of thermal properties of the elements, compounds and different materials in many industrial applications is a requirement for their final functionality. Transient plane source (tps) sensors are reported2 to be useful for the simultaneous measurement of thermal conductivity, thermal diffusivity and volumetric heat capacity of insulators, conductor liquids3 and high-TC superconductors4. The tps-sensor consists of a resistive element in the shape of double spiral made of 10 micrometer thick Ni-foils covered on both sides with 25 micrometer thick Kapton. This sensor acts both as a heat source and a resistance thermometer for recording the time dependent temperature increase. From the knowledge of the temperature co-efficient of the metal spiral, the temperature increase of the sensor can be determined precisely by placing the sensor in between two surfaces of the same material under test. This temperature increase is then related to the thermal conductivity, thermal diffusivity and volumetric heat capacity by simple relations2,5. The tps-sensor has been used to measure thermal conductivities from 0.001 Wm-1K-1to 600 Wm-1K-1 and temperature ranges covered from 77K- 1000K. This talk gives the design, advantages and limitations of the tpl-sensor along with its applications to the measurementof thermal properties in a variety of materials.

  13. Transient plane source (tps) sensors for simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and conductors

    International Nuclear Information System (INIS)

    Maqsood, Asghari; Anis-ur-Rehman, M

    2013-01-01

    Thermal conductivity and thermal diffusivity are two important physical properties for designing any food engineering processes 1 . The knowledge of thermal properties of the elements, compounds and different materials in many industrial applications is a requirement for their final functionality. Transient plane source (tps) sensors are reported 2 to be useful for the simultaneous measurement of thermal conductivity, thermal diffusivity and volumetric heat capacity of insulators, conductor liquids 3 and high-T C superconductors 4 . The tps-sensor consists of a resistive element in the shape of double spiral made of 10 micrometer thick Ni-foils covered on both sides with 25 micrometer thick Kapton. This sensor acts both as a heat source and a resistance thermometer for recording the time dependent temperature increase. From the knowledge of the temperature co-efficient of the metal spiral, the temperature increase of the sensor can be determined precisely by placing the sensor in between two surfaces of the same material under test. This temperature increase is then related to the thermal conductivity, thermal diffusivity and volumetric heat capacity by simple relations 2,5 . The tps-sensor has been used to measure thermal conductivities from 0.001 Wm −1 K −1 to 600 Wm −1 K −1 and temperature ranges covered from 77K– 1000K. This talk gives the design, advantages and limitations of the tpl-sensor along with its applications to the measurementof thermal properties in a variety of materials

  14. Characterization of Thermal Parameters for Improving Pyranometer and Pyrgeometer Measurements

    Science.gov (United States)

    Tsay, Si-Chee; Jhabvala, Murzy D.; Ji, Qiang; Rapshun, David; Shu, Peter K.

    2000-01-01

    Since the introduction of thermopile, pyranometers (solar, e.g., 0.3-3.0 micrometers) and pyrgeometers (terrestrial, e.g., 4-50 micrometers) have become instruments commonly used for measuring the broadband hemispherical irradiances at the surface in a long-term, monitoring mode for decades. These commercially available radiometers have been manufactured in several countries such as from the United States, Asia, and Europe, and are generally reliable and economical. These worldwide distributions of surface measurements become even more important in the era of Earth remote sensing in studying climate change. However, recent studies from field campaigns have pointed out that erroneous factors (e.g., temperature gradients between the filter dome and detector, emissivity of the thermopile) are responsible for the unacceptable level of uncertainty (e.g., 20 W m(exp -2)). Using a newly developed instrument of Quantum Well Infrared Photodetector (QWTP), we have characterized the brightness temperature fields of pyranometers and pyrgeometers under various sky conditions. The QWIP is based on the superlattice (GaAs/AlGaAs) technology and has a noise equivalent temperature (NEAT) less than 0.1 K. The quality of pyranometer and pyrgeometer measure- ments can be improved largely by applying proper knowledge of the thermal parameters affecting the operation of the thermopile systems. Data correction procedure and algorithm will be presented and discussed.

  15. In-situ measurements of material thermal parameters for accurate LED lamp thermal modelling

    NARCIS (Netherlands)

    Vellvehi, M.; Perpina, X.; Jorda, X.; Werkhoven, R.J.; Kunen, J.M.G.; Jakovenko, J.; Bancken, P.; Bolt, P.J.

    2013-01-01

    This work deals with the extraction of key thermal parameters for accurate thermal modelling of LED lamps: air exchange coefficient around the lamp, emissivity and thermal conductivity of all lamp parts. As a case study, an 8W retrofit lamp is presented. To assess simulation results, temperature is

  16. Assessing thermally induced errors of machine tools by 3D length measurements

    NARCIS (Netherlands)

    Florussen, G.H.J.; Delbressine, F.L.M.; Schellekens, P.H.J.

    2003-01-01

    A new measurement technique is proposed for the assessment of thermally induced errors of machine tools. The basic idea is to measure changes of length by a telescopic double ball bar (TDEB) at multiple locations in the machine's workspace while the machine is thermally excited. In addition thermal

  17. Study of thermal transitions in polymers by a multifrequency modulated DSC technique

    OpenAIRE

    Fraga Rivas, Iria

    2010-01-01

    Premi extraordinari doctorat curs 2009-2010, àmbit de Ciències Differential Scanning Calorimetry (DSC) is one of the most widely used thermal analysis techniques for the study of transitions and relaxation processes in polymers and also in other materials. It measures the heat flow as a function of time and/or temperature, and determines the energy released or absorbed by a sample when it is heated (cooled) or maintained at a constant temperature. Its advantages are that it is fast a...

  18. Changes to the forward SCT module design and their effect on thermal performance

    International Nuclear Information System (INIS)

    Lindsay, S.; Taylor, G.

    2000-01-01

    This paper presents detailed calculations of a module design of a module design with separate cooling to the hybrid and detector. In this paper, comparison of the baseline module with the separated-cooling module are presented to help identify critical elements of the baseline

  19. Methods and pitfalls of measuring thermal preference and tolerance in lizards.

    Science.gov (United States)

    Camacho, Agustín; Rusch, Travis W

    2017-08-01

    Understanding methodological and biological sources of bias during the measurement of thermal parameters is essential for the advancement of thermal biology. For more than a century, studies on lizards have deepened our understanding of thermal ecophysiology, employing multiple methods to measure thermal preferences and tolerances. We reviewed 129 articles concerned with measuring preferred body temperature (PBT), voluntary thermal tolerance, and critical temperatures of lizards to offer: a) an overview of the methods used to measure and report these parameters, b) a summary of the methodological and biological factors affecting thermal preference and tolerance, c) recommendations to avoid identified pitfalls, and d) directions for continued progress in our application and understanding of these thermal parameters. We emphasize the need for more methodological and comparative studies. Lastly, we urge researchers to provide more detailed methodological descriptions and suggest ways to make their raw data more informative to increase the utility of thermal biology studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Deficient conditioned pain modulation after spinal cord injury correlates with clinical spontaneous pain measures.

    Science.gov (United States)

    Albu, Sergiu; Gómez-Soriano, Julio; Avila-Martin, Gerardo; Taylor, Julian

    2015-02-01

    The contribution of endogenous pain modulation dysfunction to clinical and sensory measures of neuropathic pain (NP) has not been fully explored. Habituation, temporal summation, and heterotopic noxious conditioning stimulus-induced modulation of tonic heat pain intensity were examined in healthy noninjured subjects (n = 10), and above the level of spinal cord injury (SCI) in individuals without (SCI-noNP, n = 10) and with NP (SCI-NP, n = 10). Thermoalgesic thresholds, Cz/AFz contact heat evoked potentials (CHEPs), and phasic or tonic (30 seconds) heat pain intensity were assessed within the C6 dermatome. Although habituation to tonic heat pain intensity (0-10) was reported by the noninjured (10 s: 3.5 ± 0.3 vs 30 s: 2.2 ± 0.5 numerical rating scale; P = 0.003), loss of habituation was identified in both the SCI-noNP (3.8 ± 0.3 vs 3.6 ± 0.5) and SCI-NP group (4.2 ± 0.4 vs 4.9 ± 0.8). Significant temporal summation of tonic heat pain intensity was not observed in the 3 groups. Inhibition of tonic heat pain intensity induced by heterotopic noxious conditioning stimulus was identified in the noninjured (-29.7% ± 9.7%) and SCI-noNP groups (-19.6% ± 7.0%), but not in subjects with SCI-NP (+1.1% ± 8.0%; P pain modulation response correlated positively with Cz/AFz CHEP amplitude (ρ = 0.8; P = 0.015) and evoked heat pain intensity (ρ = 0.8; P = 0.007) in the SCI-NP group. Stepwise regression analysis revealed that the mean conditioned pain modulation (R = 0.72) correlated with pain severity and pressing spontaneous pain in the SCI-NP group. Comprehensive assessment of sensory dysfunction above the level of injury with tonic thermal test and conditioning stimuli revealed less-efficient endogenous pain modulation in subjects with SCI-NP.

  1. Marginal thermal-neutron peak fluxes in systems with modulation of reactivity

    International Nuclear Information System (INIS)

    Alekseev, N.I.; Stolypin, V.S.

    1978-01-01

    A possibility of obtaining high (including marginal) thermal neutron peak fluxes PHIsub(m) in a light water trap of a pulsed fast reactor with modulation of reactivity has been studied. The dependences of sub(m) on the subcriticality and supercriticality as well as on the supercritical state duration have been calculated on stepped variations of the reactivity. The calculations show that PHIsub(m) of about 7.3x10 18 neutron/cm 2 xs with the effective pulse duration of approximately 150 μc, pulse frequency of approximately 1 Hz and at fuel temperature of approximately 1300 deg C can be obtained with the reactor. The comparative calculations show that sub(m) is 1.5 times higher than that of a booster obtained using a ''meson plant'' (designs of the booster and the reactor are equivalent). The neutron background between pulses in the reactor is much lower than in the booster, and there is no need for a power injector in the reactor altogether. Meanwhile the maximum attainable PHIsub(m) for the booster and the reactor are the same and equal approximately 2x10 19 neutron/cm 2 xs

  2. Measurement of thermal conductivity and diffusivity in situ: Literature survey and theoretical modelling of measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kukkonen, I.; Suppala, I. [Geological Survey of Finland, Espoo (Finland)

    1999-01-01

    In situ measurements of thermal conductivity and diffusivity of bedrock were investigated with the aid of a literature survey and theoretical simulations of a measurement system. According to the surveyed literature, in situ methods can be divided into `active` drill hole methods, and `passive` indirect methods utilizing other drill hole measurements together with cutting samples and petrophysical relationships. The most common active drill hole method is a cylindrical heat producing probe whose temperature is registered as a function of time. The temperature response can be calculated and interpreted with the aid of analytical solutions of the cylindrical heat conduction equation, particularly the solution for an infinite perfectly conducting cylindrical probe in a homogeneous medium, and the solution for a line source of heat in a medium. Using both forward and inverse modellings, a theoretical measurement system was analysed with an aim at finding the basic parameters for construction of a practical measurement system. The results indicate that thermal conductivity can be relatively well estimated with borehole measurements, whereas thermal diffusivity is much more sensitive to various disturbing factors, such as thermal contact resistance and variations in probe parameters. In addition, the three-dimensional conduction effects were investigated to find out the magnitude of axial `leak` of heat in long-duration experiments. The radius of influence of a drill hole measurement is mainly dependent on the duration of the experiment. Assuming typical conductivity and diffusivity values of crystalline rocks, the measurement yields information within less than a metre from the drill hole, when the experiment lasts about 24 hours. We propose the following factors to be taken as basic parameters in the construction of a practical measurement system: the probe length 1.5-2 m, heating power 5-20 Wm{sup -1}, temperature recording with 5-7 sensors placed along the probe, and

  3. Measurement of thermal conductivity and diffusivity in situ: Literature survey and theoretical modelling of measurements

    International Nuclear Information System (INIS)

    Kukkonen, I.; Suppala, I.

    1999-01-01

    In situ measurements of thermal conductivity and diffusivity of bedrock were investigated with the aid of a literature survey and theoretical simulations of a measurement system. According to the surveyed literature, in situ methods can be divided into 'active' drill hole methods, and 'passive' indirect methods utilizing other drill hole measurements together with cutting samples and petrophysical relationships. The most common active drill hole method is a cylindrical heat producing probe whose temperature is registered as a function of time. The temperature response can be calculated and interpreted with the aid of analytical solutions of the cylindrical heat conduction equation, particularly the solution for an infinite perfectly conducting cylindrical probe in a homogeneous medium, and the solution for a line source of heat in a medium. Using both forward and inverse modellings, a theoretical measurement system was analysed with an aim at finding the basic parameters for construction of a practical measurement system. The results indicate that thermal conductivity can be relatively well estimated with borehole measurements, whereas thermal diffusivity is much more sensitive to various disturbing factors, such as thermal contact resistance and variations in probe parameters. In addition, the three-dimensional conduction effects were investigated to find out the magnitude of axial 'leak' of heat in long-duration experiments. The radius of influence of a drill hole measurement is mainly dependent on the duration of the experiment. Assuming typical conductivity and diffusivity values of crystalline rocks, the measurement yields information within less than a metre from the drill hole, when the experiment lasts about 24 hours. We propose the following factors to be taken as basic parameters in the construction of a practical measurement system: the probe length 1.5-2 m, heating power 5-20 Wm -1 , temperature recording with 5-7 sensors placed along the probe, and

  4. Development of Thermal-hydraulic Analysis Methodology for Multi-module Breeding Blankets in K-DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon-Woo; Lee, Jeong-Hun; Park, Goon-Cherl; Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of); Im, Kihak [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    In this paper, the purpose of the analyses is to extend the capability of MARS-KS to the entire blanket system which includes a few hundreds of single blanket modules. Afterwards, the plan for the whole blanket system analysis using MARS-KS is introduced and the result of the multiple blanket module analysis is summarized. A thermal-hydraulic analysis code for a nuclear reactor safety, MARS-KS, was applied for the conceptual design of the K-DEMO breeding blanket thermal analysis. Then, a methodology to simulate multiple blanket modules was proposed, which uses a supervisor program to handle each blanket module individually at first and then distribute the flow rate considering pressure drops arises in each module. For a feasibility test of the proposed methodology, 10 outboard blankets in a toroidal field sector were simulated, which are connected with each other through the inlet and outlet common headers. The calculation results of flow rates, pressure drops, and temperatures showed the validity of the calculation and thanks to the parallelization using MPI, almost linear speed-up could be obtained.

  5. Angle Resolved Performance Measurements on PV Glass and Modules

    DEFF Research Database (Denmark)

    Juutilainen, Line Tollund; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    The angular response of PV-modules has significant impact on the energy production. This is especially pronounced in BIPV where installation angles often are far from optimal. Nevertheless, a gain in energy yield may be obtained by choosing a proper glass as superstrate. In this work we present...... the concept of PV balconies as cost efficient and easy way of integrating PV into buildings. The experimental work consists of the fabrication of single cell mini modules with different glass covering, and characterizing their angular response in a custom made setup, where only the direct sunlight is used...... as a light source. As a special case we estimate the annual yield for each glass in the case of PV balconies for a specific geographical location and orientation of the module....

  6. Accurate photopyroelectric measurements of thermal diffusivity of (semi)liquids

    NARCIS (Netherlands)

    Dadarlat, D.; Neamtu, C.; Surducan, E.; Sahraoui, A.H.; Longuemart, S.; Bicanic, D.

    2002-01-01

    The back photopyroelectric (PPE) configuration, with opaque sample and thermally thick sample and sensor, was applied in order to obtain room temperature values of the thermal diffusivity of some (semi)liquid materials. The methodology is based on a sample's thickness scan, and not on a frequency

  7. Thermal Properties of Some Organic Liquids Using Ultrasonic Velocity Measurements

    Directory of Open Access Journals (Sweden)

    P. Ramadoss

    2011-01-01

    Full Text Available Debye temperature and thermal relaxation time has been calculated in normal and boiling temperature. Using thermal relaxation time, the heat of fusion has been calculated for nineteen organic liquids and the results throw light on the method of calculating heat of fusion.

  8. Sliding force measurements of the LHC RF contact Plug In Modules at 15 K and in UHV

    CERN Document Server

    Artoos, K; Renaglia, T; CERN. Geneva. TS Department

    2008-01-01

    Some sliding RF contacts mounted in the Plug In Modules in the LHC interconnects failed during a thermal cycle between 4.2 K and room temperature. Some of the gold-coated copper-beryllium RF fingers buckled during the warm up of the machine, indicating that one or more parameters during operation (e.g. the friction coefficient) could be different from what was used in the calculations. This report describes the measurement of the longitudinal forces acting on the sliding RF fingers at operating vacuum and temperatures.

  9. Sliding force measurements on the LHC RF contact Plug In Modules at 15 K and in UHV

    CERN Document Server

    Artoos, K; Renaglia, T

    2008-01-01

    Some sliding RF contacts mounted in the Plug In Modules in the LHC interconnects failed during a thermal cycle between 4.2 K and room temperature. Gold-coated copperberyllium RF fingers buckled during the warm up of the machine, indicating that one or more parameters during operation (e.g. the friction coefficient under vacuum) could be different from what was used in the calculations. This report describes the measurement of the longitudinal forces acting on the sliding RF fingers at operating vacuum and temperatures.

  10. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Fasong [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Tan, Yidong; Zhang, Shulian, E-mail: zsl-dpi@mail.tsinghua.edu.cn [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Lin, Jing; Ding, Yingchun [Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-04-15

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10{sup −6}(K{sup −1}) at the range of 298 K–598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K–748 K.

  11. All-optical time-resolved measurement of laser energy modulation in a relativistic electron beam

    Directory of Open Access Journals (Sweden)

    D. Xiang

    2011-11-01

    Full Text Available We propose and demonstrate an all-optical method to measure laser energy modulation in a relativistic electron beam. In this scheme the time-dependent energy modulation generated from the electron-laser interaction in an undulator is converted into time-dependent density modulation with a chicane, which is measured to infer the laser energy modulation. The method, in principle, is capable of simultaneously providing information on femtosecond time scale and 10^{-5} energy scale not accessible with conventional methods. We anticipate that this method may have wide applications in many laser-based advanced beam manipulation techniques.

  12. Development of a Novel Scanning Thermal Microscopy (SThM) Method to Measure the Thermal Conductivity of Biological Cells.

    Science.gov (United States)

    Nakanishi, Kouichi; Kogure, Akinori; Kuwana, Ritsuko; Takamatsu, Hiromu; Ito, Kiyoshi

    2017-01-01

     Differences in the physical properties of individual cells cannot be evaluated with conventional experimental methods that are used to study groups of cells obtained from pure cultures. To examine the differences in the thermal tolerance of individual cells that are genetically identical, a method is needed to measure the thermal energy required to kill single cells. We developed a scanning thermal microscopy (SThM) system and measured the thermal conductivity of various bacterial cells, for example, spore formeing Bacillus genus and non spore-forming bacteria such as Escherichia coli. The thermal conductivity of vegetative cells (0.61 to 0.75 W/m・K) was found to be higher than that of spores (0.29 to 0.45 W/m・K). Furthermore the newly developed method enables us to estimate the thermal energy needed to kill individual cells or spores. We believe that this method can estimate the thermal energy required to achieve the cell for sterilization by heating.

  13. Measuring modules for the research of compensators of reactive power with voltage stabilization in MATLAB

    Science.gov (United States)

    Vlasayevsky, Stanislav; Klimash, Stepan; Klimash, Vladimir

    2017-10-01

    A set of mathematical modules was developed for evaluation the energy performance in the research of electrical systems and complexes in the MatLab. In the electrotechnical library SimPowerSystems of the MatLab software, there are no measuring modules of energy coefficients characterizing the quality of electricity and the energy efficiency of electrical apparatus. Modules are designed to calculate energy coefficients characterizing the quality of electricity (current distortion and voltage distortion) and energy efficiency indicators (power factor and efficiency) are presented. There are described the methods and principles of building the modules. The detailed schemes of modules built on the elements of the Simulink Library are presented, in this connection, these modules are compatible with mathematical models of electrical systems and complexes in the MatLab. Also there are presented the results of the testing of the developed modules and the results of their verification on the schemes that have analytical expressions of energy indicators.

  14. Thermal diffusivity measurement by lock-in photothermal shadowgraph method

    Energy Technology Data Exchange (ETDEWEB)

    Cifuentes, A. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Ciudad de México 11500 (Mexico); Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao (Spain); Alvarado, S. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Ciudad de México 11500 (Mexico); Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, Heverlee B-3001 (Belgium); Cabrera, H. [Centro Multidisciplinario de Ciencias, Instituto Venezolano de Investigaciones Científicas, IVIC, Mérida 5101, Venezuela and SPIE-ICTP Anchor Research in Optics Program Lab, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste (Italy); Calderón, A.; Marín, E., E-mail: emarinm@ipn.mx [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Ciudad de México 11500 (Mexico)

    2016-04-28

    Here, we present a novel application of the shadowgraph technique for obtaining the thermal diffusivity of an opaque solid sample, inspired by the orthogonal skimming photothermal beam deflection technique. This new variant utilizes the shadow projected by the sample when put against a collimated light source. The sample is then heated periodically by another light beam, giving rise to thermal waves, which propagate across it and through its surroundings. Changes in the refractive index of the surrounding media due to the heating distort the shadow. This phenomenon is recorded and lock-in amplified in order to determine the sample's thermal diffusivity.

  15. Electro-optic modulation measurement technique and enhancement

    DEFF Research Database (Denmark)

    Jacobsen, Rune Shim

    2005-01-01

    indeks bølgeleder blev påbegyndt. Når denne koefficient opnås i en sådan bølgeleder vil fremtidige forsøg kunne fastlægge hvor stor den inducerede ikke-lineare koefficient i silicium kan blive. Fremtidige forsøg vil også fastlægge om den inducerede effekt eksisterer for hurtig elektrisk modulation....

  16. Thermal Design and Performance results of the first High-Beta Cryo-module for HIE-ISOLDE at CERN

    International Nuclear Information System (INIS)

    Valdarno, L; Delruelle, N; Leclercq, Y; Parma, V; Vandoni, G; Williams, L

    2015-01-01

    The High Energy and Intensity HIE-ISOLDE is a facility under construction at CERN whose target is ultimately, after the installation of six cryo-modules, to produce radioactive ion beams at 10MeV/u maximum energy in order to significantly expand the nuclear physics programme carried out by REX-ISOLDE. Since thermal control is essential to the performance of the whole cryo-module, a combination of a passive (materials, coatings, and surface finishes) and active (cryogenic loops, heaters) control has been designed to keep the cryostat operating within the allowable thermal budget. A numerical model based on Finite Element has been developed in order to generate a faithful global mapping of temperatures and heat fluxes inside the cryo-module. The numerical model, combined with the experimental results of the first test campaign, will serve as an optimization tool for the future cryo-modules in terms of improvement in the global and specific heat loads management. (paper)

  17. A thermal comparator sensor for measuring autogenous deformation in hardening Portland cement paste

    DEFF Research Database (Denmark)

    Østergaard, Thomas; Jensen, Ole Mejlhede

    2003-01-01

    This paper describes a simple and accurate experimental device specially developed to measure autogenous deformation in hardening cement-based materials. The measuring system consists of a so-called thermal comparator sensor and a modular thermostatically controlled system. The operating principle...... of the thermal comparator is based on thermal expansion of aluminium. A particular characteristic of the measuring system is the fixation of the thermal comparator sensor to the deforming specimen. The modular system ensures effective thermostatic control of the hydrating cement paste samples. The technique...... allows continuous measurement with high accuracy of the linear deformation as well as determination of the activation energy of autogenous deformation....

  18. Results of measurements of thermal interaction between molten metal and water

    International Nuclear Information System (INIS)

    Zyszkowski, W.

    1975-10-01

    The report describes results of an experimental investigation into thermal interaction of molten metals with water. The experiments were performed in two stages: the aim of the first stage was to study the general character of thermal interaction between molten metal and water and to measure the Leidenfrost temperature of the inverse Leidenfrost phenomenon. The second stage was directed to the experimental study of the triggering mechanism of thermal explosion. The experimental material gathered in this study includes: 1) transient temperature measurements in the hot material and in water, 2) measurements of pressure and reactive force combined with thermal explosion, 3) high-speed films of thermal interaction, 4) investigation results of thermal explosion debris (microscopic, mechanical, metallographical and chemical). The most significant observation is, that small jets from the main particle mass occuring 1 to 10 msec before, precede thermal explosion. (orig.) [de

  19. 10 CFR 431.224 - Uniform test method for the measurement of energy consumption for traffic signal modules and...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Uniform test method for the measurement of energy consumption for traffic signal modules and pedestrian modules. 431.224 Section 431.224 Energy DEPARTMENT OF... measurement of energy consumption for traffic signal modules and pedestrian modules. (a) Scope. This section...

  20. Note: Development of a microfabricated sensor to measure thermal conductivity of picoliter scale liquid samples.

    Science.gov (United States)

    Park, Byoung Kyoo; Yi, Namwoo; Park, Jaesung; Kim, Dongsik

    2012-10-01

    This paper presents a thermal analysis device, which can measure thermal conductivity of picoliter scale liquid sample. We employ the three omega method with a microfabricated AC thermal sensor with nanometer width heater. The liquid sample is confined by a micro-well structure fabricated on the sensor surface. The performance of the instrument was verified by measuring the thermal conductivity of 27-picoliter samples of de-ionized (DI) water, ethanol, methanol, and DI water-ethanol mixtures with accuracies better than 3%. Furthermore, another analytical scheme allows real-time thermal conductivity measurement with 5% accuracy. To the best of our knowledge, this technique requires the smallest volume of sample to measure thermal property ever.

  1. Application of Hot-wire Method for Measuring Thermal Conductivity of Fine Ceramics

    Directory of Open Access Journals (Sweden)

    Shangxi WANG

    2016-11-01

    Full Text Available Ceramic substrate is preferred in high density packaging due to its high electrical resistivity and moderate expansion coefficient. The thermal conductivity is a key parameter for packaging substrates. There are two common methods to measure the thermal conductivity, which are the hot-wire method and the laser-flash method. Usually, the thermal conductivities of porcelain is low and meet the measurement range of hot-wire method, and the measured value by hot-wire method has little difference with that by laser-flash method. In recent years, with the requirement of high-powered LED lighting, some kinds of ceramic substrates with good thermal conductivity have been developed and their thermal conductivity always measured by the means of laser flash method, which needs expensive instrument. In this paper, in order to detect the thermal conductivity of fine ceramic with convenience and low cost, the feasibility of replacing the laser flash method with hot wire method to measure thermal conductivity of ceramic composites was studied. The experiment results showed that the thermal conductivity value of fine ceramics measured by the hot-wire method is severely lower than that by the laser-flash method. However, there is a positive relationship between them. It is possible to measure the thermal conductivity of fine ceramic workpiece instantly by hot-wire method via a correction formula.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12543

  2. Measuring of nonlinearity of dye doped liquid crystals using of self phase modulation effect

    International Nuclear Information System (INIS)

    Abedi, M.; Jafari, A.; Tajalli, H.

    2007-01-01

    Self phase modulation in dye doped liquid crystals has investigated and the nonlinearity of dye doped liquid crystals is measured by this effect. The Self phase modulation effect can be used for producing optical micro rings that have many applications in photonics and laser industries.

  3. Magnet measurement interfacing to the G-64 Euro standard bus and testing G-64 modules

    International Nuclear Information System (INIS)

    Hogrefe, R.L.

    1995-01-01

    The Magnet Measurement system utilizes various modules with a G-64 Euro (Gespac) Standard Interface. All modules are designed to be software controlled, normally under the constraints of the OS-9 operating system with all data transfers to a host computer accomplished by a serial link

  4. Meteorological Instrumentation and Measurements Open Resource Training Modules for Undergraduate and Graduate Education

    Science.gov (United States)

    Rockwell, A.; Clark, R. D.; Stevermer, A.

    2017-12-01

    The National Center for Atmospheric Research Earth Observing Laboratory, Millersville University and The COMET Program are collaborating to produce a series of nine online modules on the the topic of meteorological instrumentation and measurements. These interactive, multimedia educational modules can be integrated into undergraduate and graduate meteorology courses on instrumentation, measurement science, and observing systems to supplement traditional pedagogies and enhance blended instruction. These freely available and open-source training tools are designed to supplement traditional pedagogies and enhance blended instruction. Three of the modules are now available and address the theory and application of Instrument Performance Characteristics, Meteorological Temperature Instrumentation and Measurements, and Meteorological Pressure Instrumentation and Measurements. The content of these modules is of the highest caliber as it has been developed by scientists and engineers who are at the forefront of the field of observational science. Communicating the availability of these unique and influential educational resources with the community is of high priority. These modules will have a profound effect on the atmospheric observational sciences community by fulfilling a need for contemporary, interactive, multimedia guided education and training modules integrating the latest instructional design and assessment tools in observational science. Thousands of undergraduate and graduate students will benefit, while course instructors will value a set of high quality modules to use as supplements to their courses. The modules can serve as an alternative to observational research training and fill the void between field projects or assist those schools that lack the resources to stage a field- or laboratory-based instrumentation experience.

  5. Experimental study on the effects of the number of heat exchanger modules on thermal characteristics in a premixed combustion system

    International Nuclear Information System (INIS)

    Yu, Byeonghun; Lee, Chang-Eon; Kum, Sung Min; Lee, Seungro

    2016-01-01

    The effects of the number of heat exchanger modules on thermal characteristics were experimentally studied in a premixed combustion system with a cross-flow staggered-tube heat exchanger. The various heat exchanger modules, from 4 to 8, combined with a premixed burner were tested to investigate the performance of the heat exchanger through the surface area of the heat exchanger at various equivalence ratios. Additionally, the performance of the heat exchanger was analyzed by applying entropy generation theory to the heat exchanger system. As a result, although the heat transfer rate increases with the increase of the equivalence ratio, the NOx and CO concentrations also increase due to the increasing flame temperature. In addition, the entropy generation increases with an increase of the equivalence ratio. Furthermore, the heat transfer rate and the effectiveness are increased with the increase of the number of the heat exchanger modules. Also, the effectiveness is sharply increased when the number of the heat exchanger modules is increased from 4 to 5. Consequently, the optimal operating conditions regarding pollutant emission, effectiveness and entropy generation in this experimental range are 0.85 for the equivalence ratio and 8 for the number of heat exchanger modules

  6. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change...... material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module......, recommendations on how best to transfer heat to and from the seasonal heat storage module are given....

  7. Aluminum nitride coatings using response surface methodology to optimize the thermal dissipated performance of light-emitting diode modules

    Science.gov (United States)

    Jean, Ming-Der; Lei, Peng-Da; Kong, Ling-Hua; Liu, Cheng-Wu

    2018-05-01

    This study optimizes the thermal dissipation ability of aluminum nitride (AlN) ceramics to increase the thermal performance of light-emitting diode (LED) modulus. AlN powders are deposited on heat sink as a heat interface material, using an electrostatic spraying process. The junction temperature of the heat sink is developed by response surface methodology based on Taguchi methods. In addition, the structure and properties of the AlN coating are examined using X-ray photoelectron spectroscopy (XPS). In the XPS analysis, the AlN sub-peaks are observed at 72.79 eV for Al2p and 398.88 eV for N1s, and an N1s sub-peak is assigned to N-O at 398.60eV and Al-N bonding at 395.95eV, which allows good thermal properties. The results have shown that the use of AlN ceramic material on a heat sink can enhance the thermal performance of LED modules. In addition, the percentage error between the predicted and experimental results compared the quadric model with between the linear and he interaction models was found to be within 7.89%, indicating that it was a good predictor. Accordingly, RSM can effectively enhance the thermal performance of an LED, and the beneficial heat dissipation effects for AlN are improved by electrostatic spraying.

  8. Instrument for Measuring Thermal Conductivity of Materials at Low Temperatures

    Science.gov (United States)

    Fesmire, James; Sass, Jared; Johnson, Wesley

    2010-01-01

    With the advance of polymer and other non-metallic material sciences, whole new series of polymeric materials and composites are being created. These materials are being optimized for many different applications including cryogenic and low-temperature industrial processes. Engineers need these data to perform detailed system designs and enable new design possibilities for improved control, reliability, and efficiency in specific applications. One main area of interest is cryogenic structural elements and fluid handling components and other parts, films, and coatings for low-temperature application. An important thermal property of these new materials is the apparent thermal conductivity (k-value).

  9. Rating PV Power and Energy: Cell, Module, and System Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  10. Iodine-frequency-stabilized laser diode and displacement-measuring interferometer based on sinusoidal phase modulation

    Science.gov (United States)

    Duong, Quang Anh; Vu, Thanh Tung; Higuchi, Masato; Wei, Dong; Aketagawa, Masato

    2018-06-01

    We propose a sinusoidal phase modulation method to achieve both the frequency stabilization of an external-cavity laser diode (ECLD) to an 127I2 saturated absorption transition near 633 nm and displacement measurement using a Mach–Zehnder interferometer. First, the frequency of the ECLD is stabilized to the b 21 hyperfine component of the P(33) 6-3 transition of 127I2 by combining sinusoidal phase modulation by an electro-optic modulator and frequency modulation spectroscopy by chopping the pump beam using an acousto-optic modulator. Even though a small modulation index of m  =  3.768 rad is utilized, a relative frequency stability of 10‑11 order is obtained over a sampling time of 400 s. Secondly, the frequency-stabilized ECLD is applied as a light source to a Mach–Zehnder interferometer. From the two consecutive modulation harmonics (second and third orders) involved in the interferometer signal, the displacement of the moving mirror is determined for four optical path differences (L 0  =  100, 200, 500, and 1000 mm). The measured modulation indexes for the four optical path differences coincide with the designated value (3.768 rad) within 0.5%. Compared with the sinusoidal frequency modulation Michelson interferometer (Vu et al 2016 Meas. Sci. Technol. 27 105201) which was demonstrated by some of the same authors of this paper, the phase modulation Mach–Zhender interferometer could fix the modulation index to a constant value for the four optical path differences. In this report, we discuss the measurement principle, experimental system, and results.

  11. Electrical Parasitics and Thermal Modeling for Optimized Layout Design of High Power SiC Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Blaabjerg, Frede; Dutta, Atanu

    2016-01-01

    , the presented models are verified by a conventional and an optimized power module layout. The optimized layout is designed based on the reduction of stray inductance and temperature in a P-cell and N-cell half-bridge module. The presented models are verified by FEM simulations and also experiment....

  12. Application of pulsed power and power modulation to the non-thermal plasma treatment of hazardous gaseous wastes

    International Nuclear Information System (INIS)

    Penetrante, B.M.

    1992-10-01

    Acid rain, global warming, ozone depletion, and smog are preeminent environmental problems facing the world today. Non-thermal plasma techniques offer an innovative approach to the cost-effective solution of these problems. Many potential applications of non-thermal plasmas to air pollution control have already been demonstrated. The use of pulsed power and power modulation is essential to the successful implementation of non-thermal plasma techniques. This paper provides an overview of the most recent developments in non-thermal plasma systems that have been applied to gaseous waste treatment. In the non-thermal plasma approach, the nonequilibrium properties of the plasma are fully exploited. These plasmas are characterized by high electron temperatures, while the gas remains at near ambient temperature and pressure. The energy is directed preferentially to the undesirable components, which are often present in very small concentrations. These techniques utilize the dissociation and ionization of the background gas to produce radicals which, in turn, decompose the toxic compounds. The key to success in the non-thermal plasma approach is to produce a discharge in which the majority of the electrical energy goes into the production of energetic electrons, rather than into gas heating. For example, in a typical application to flue gas cleanup, these electrons produce radicals, such as O and OH, through the dissociation or ionization of molecules such as H 2 O or O 2 . The radicals diffuse through the gas and preferentially oxidize the nitrogen oxides and sulfur oxides to form acids that can then be easily neutralized to form non-toxic, easily-collectible (and commercially salable) compounds. Non-thermal plasmas can be created in essentially two different ways: by electron-beam irradiation, and by electrical discharges

  13. Measurement of thermal properties of magnetic nanoparticles using infrared thermal microscopy

    DEFF Research Database (Denmark)

    Kim, Jae Young; Chang, Ki Soo; Kook, Myung Ho

    2013-01-01

    Magnetic nanoparticles (MNPs) are considered promising for biomedical applications such as hyperthermia treatment and disease diagnosis owing to their distinctive thermal properties. For these applications, it is essential to screen the temperature distribution in the targeted disease site....... This study aimed to investigate and observe the thermal properties of a small amount of MNPs used as highly sensitive biomarkers for disease diagnosis by microthermography. Toward this end, we used polyacrylamide and agarose phantoms containing a small amount of MNPs (30 mg Fe-1). In phantoms, the increasing...

  14. A method of measuring the thermal conductivity of liquids

    NARCIS (Netherlands)

    Held, E.F.M. van der; Drunen, F.G. van

    1949-01-01

    We described the development of an apparatus for the determination of the thermal conductivity of liquids. The apparatus is suitable for all kinds of liquids, including the strongest acids. From a given time we pass an electric current through a thin straight wire, placed in a homogeneous material

  15. Quantitative measurement of productivity loss due to thermal discomfort

    DEFF Research Database (Denmark)

    Lan, Li; Wargocki, Pawel; Lian, Zhiwei

    2011-01-01

    discomfort caused by elevated air temperature had a negative effect on performance. A quantitative relationship was established between thermal sensation votes and task performance. It can be used for economic calculations pertaining to building design and operation when occupant productivity is considered...

  16. Measurement of the stimulated thermal Rayleigh scattering instability

    International Nuclear Information System (INIS)

    Karr, T.J.; Rushford, M.C.; Murray, J.R.; Morris, J.R.

    1989-04-01

    Growth of perturbations due to stimulated thermal Rayleigh scattering was observed on a laser beam propagating in a 1 meter cell of CC14. Initial sinusoidal irradiance perturbations were seeded onto the laser leam, and their amplification in the cell was recorded by a near field camera. The perturbation growth rate is in agreement with analytical predictions of linearized propagation theory

  17. Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

    Science.gov (United States)

    Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

    2014-09-20

    This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

  18. Validation of CESAR Thermal-hydraulic Module of ASTEC V1.2 Code on BETHSY Experiments

    Science.gov (United States)

    Tregoures, Nicolas; Bandini, Giacomino; Foucher, Laurent; Fleurot, Joëlle; Meloni, Paride

    The ASTEC V1 system code is being jointly developed by the French Institut de Radioprotection et Sûreté Nucléaire (IRSN) and the German Gesellschaft für Anlagen und ReaktorSicherheit (GRS) to address severe accident sequences in a nuclear power plant. Thermal-hydraulics in primary and secondary system is addressed by the CESAR module. The aim of this paper is to present the validation of the CESAR module, from the ASTEC V1.2 version, on the basis of well instrumented and qualified integral experiments carried out in the BETHSY facility (CEA, France), which simulates a French 900 MWe PWR reactor. Three tests have been thoroughly investigated with CESAR: the loss of coolant 9.1b test (OECD ISP N° 27), the loss of feedwater 5.2e test, and the multiple steam generator tube rupture 4.3b test. In the present paper, the results of the code for the three analyzed tests are presented in comparison with the experimental data. The thermal-hydraulic behavior of the BETHSY facility during the transient phase is well reproduced by CESAR: the occurrence of major events and the time evolution of main thermal-hydraulic parameters of both primary and secondary circuits are well predicted.

  19. Measurement of Linear Coefficient of Thermal Expansion and Temperature-Dependent Refractive Index Using Interferometric System

    Science.gov (United States)

    Corsetti, James A.; Green, William E.; Ellis, Jonathan D.; Schmidt, Greg R.; Moore, Duncan T.

    2017-01-01

    A system combining an interferometer with an environmental chamber for measuring both coefficient of thermal expansion (CTE) and temperature-dependent refractive index (dn/dT) simultaneously is presented. The operation and measurement results of this instrument are discussed.

  20. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    Energy Technology Data Exchange (ETDEWEB)

    Zavattini, G.; Ejlli, A. [Universita di Ferrara, Dipt. di Fisica e Scienze della Terra (Italy); INFN, Sezione di Ferrara (Italy); Della Valle, F. [Universita di Trieste, Dipt. di Fisica, Trieste (Italy); INFN, Sezione di Trieste, TS (Italy); Ruoso, G. [INFN, Lab. Nazionali di Legnaro (Italy)

    2016-05-15

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the measurement of the magnetic birefringence of vacuum with the HERA superconducting magnets in the ALPS-II configuration is discussed. (orig.)

  1. Relationship Between Peripheral and Psychophysical Measures of Amplitude Modulation Detection in Cochlear Implant Users.

    Science.gov (United States)

    Tejani, Viral D; Abbas, Paul J; Brown, Carolyn J

    This study investigates the relationship between electrophysiological and psychophysical measures of amplitude modulation (AM) detection. Prior studies have reported both measures of AM detection recorded separately from cochlear implant (CI) users and acutely deafened animals, but no study has made both measures in the same CI users. Animal studies suggest a progressive loss of high-frequency encoding as one ascends the auditory pathway from the auditory nerve to the cortex. Because the CI speech processor uses the envelope of an ongoing acoustic signal to modulate pulse trains that are subsequently delivered to the intracochlear electrodes, it is of interest to explore auditory nerve responses to modulated stimuli. In addition, psychophysical AM detection abilities have been correlated with speech perception outcomes. Thus, the goal was to explore how the auditory nerve responds to AM stimuli and to relate those physiologic measures to perception. Eight patients using Cochlear Ltd. Implants participated in this study. Electrically evoked compound action potentials (ECAPs) were recorded using a 4000 pps pulse train that was sinusoidally amplitude modulated at 125, 250, 500, and 1000 Hz rates. Responses were measured for each pulse over at least one modulation cycle for an apical, medial, and basal electrode. Psychophysical modulation detection thresholds (MDTs) were also measured via a three-alternative forced choice, two-down, one-up adaptive procedure using the same modulation frequencies and electrodes. ECAPs were recorded from individual pulses in the AM pulse train. ECAP amplitudes varied sinusoidally, reflecting the sinusoidal variation in the stimulus. A modulated response amplitude (MRA) metric was calculated as the difference in the maximal and minimum ECAP amplitudes over the modulation cycles. MRA increased as modulation frequency increased, with no apparent cutoff (up to 1000 Hz). In contrast, MDTs increased as the modulation frequency increased. This

  2. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    DEFF Research Database (Denmark)

    Wu, Rui; Wang, Huai; Pedersen, Kristian Bonderup

    2016-01-01

    A basic challenge in the IGBT transient simulation study is to obtain the realistic junction temperature, which demands not only accurate electrical simulations but also precise thermal impedance. This paper proposed a transient thermal model for IGBT junction temperature simulations during short...

  3. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges.

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  4. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  5. Heat capacity measurements on ThO2 by temperature modulated differential scanning calorimetry (TMDSC)

    International Nuclear Information System (INIS)

    Venkatakrishnan, R.; Nagarajan, K.; Vasudeva Rao, P.R.

    2001-01-01

    Heat capacity measurements were carried out on ThO 2 in the temperature range 330-820 K by using temperature modulated DSC. An underlying heating rate of 5 K. min -1 , a temperature modulation with an amplitude of 0.398K and a period of 150s were used for these measurements. The heat capacity values are within ± 2-4% of the literature data. (author)

  6. Thermal sensation during mild hyperthermia is modulated by acute postural change in humans

    Science.gov (United States)

    Takeda, Ryosuke; Imai, Daiki; Suzuki, Akina; Ota, Akemi; Naghavi, Nooshin; Yamashina, Yoshihiro; Hirasawa, Yoshikazu; Yokoyama, Hisayo; Miyagawa, Toshiaki; Okazaki, Kazunobu

    2016-12-01

    Thermal sensation represents the primary stimulus for behavioral and autonomic thermoregulation. We assessed whether the sensation of skin and core temperatures for the driving force of behavioral thermoregulation was modified by postural change from the supine (Sup) to sitting (Sit) during mild hyperthermia. Seventeen healthy young men underwent measurements of noticeable increase and decrease (±0.1 °C/s) of skin temperature (thresholds of warm and cold sensation on the skin, 6.25 cm2 of area) at the forearm and chest and of the whole-body warm sensation in the Sup and Sit during normothermia (NT; esophageal temperature (Tes), ˜36.6 °C) and mild hyperthermia (HT; Tes, ˜37.2 °C; lower legs immersion in 42 °C of water). The threshold for cold sensation on the skin at chest was lower during HT than NT in the Sit ( P body posture or temperature. The whole-body warm sensation was higher during HT than NT in both postures and higher in the Sit than Sup during both NT and HT (all, P cold on the skin and more whole-body warmth.

  7. 47 CFR 2.1513 - Measurements of modulation characteristics.

    Science.gov (United States)

    2010-10-01

    ... AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS FCC Procedure for Testing Class A, B and S... waveform. Step (3) Measure the period (T) of the waveform. The period is the time difference between the... results will be obtained. Step (3) Measure the maximum voltage (Vmax), and the minimum voltage (Vmin) for...

  8. Measuring technique of super high temperature thermal properties of reactor core materials

    International Nuclear Information System (INIS)

    Ono, Akira; Baba, Tetsuya; Watanabe, Hideo; Matsumoto, Tsuyoshi

    1998-01-01

    In this study, thermal properties of reactor core materials used for water cooled reactors and FBR were tried to develop a technique to measure their melt states at less than 3,000degC in order to contribute more correct evaluation of the reactor core behavior at severe accident. Then, a thermal property measuring method of high temperature melt by using floating method was investigated and its fundamental design was begun to investigate under a base of optimum judgement on the air flow floating throw-down method. And, in order to measure emissivity of melt specimen surface essential for correct temperature measurement using the throw down method, a spectroscopic emissivity measuring unit using an ellipsometer was prepared and induced. On the thermal properties measurement using the holding method, a specimen container to measure thermal diffusiveness of the high temperature melts by using laser flashing method was tried to prepare. (G.K.)

  9. Simulation of thermal properties of the silicon detector modules in ATLAS

    CERN Document Server

    Duerdoth, I P; Yuldashev, B S

    2002-01-01

    The temperature distribution and power flow from cell on the Silicon Module of the Forward Semiconductor Tracker in the ATLAS experiment have been simulated for irradiated detector. Power generated by conduction was compared for the modules with one and two cooling points. To obtain an optimal cooling temperature, the temperature of the hottest cell was plotted against power on the silicon module. The analysis of the approximation function and values for the critical power for each cooling temperature are presented. The optimal value of the cooling temperature occurred to be 260 K. (author)

  10. A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

    International Nuclear Information System (INIS)

    Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

    2017-01-01

    This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler–Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges. (paper)

  11. A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

    Science.gov (United States)

    Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

    2017-08-01

    This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler-Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges.

  12. A large amount synthesis of nanopowder using modulated induction thermal plasmas synchronized with intermittent feeding of raw materials

    International Nuclear Information System (INIS)

    Tanaka, Y; Tsuke, T; Guo, W; Uesugi, Y; Ishijima, T; Watanabe, S; Nakamura, K

    2012-01-01

    A large amount synthesis method for titanium dioxide (TiO 2 ) nanopowder is proposed by direct evaporation of titanium powders using Ar-O 2 pulse-modulated induction thermal plasma (PMITP). To realize a large amount synthesis of nanopowder, the PMITP method was combined with the intermittent and heavy load feeding of raw material powder, as well as the quenching gas injection. The intermittent powder feeding was synchronized with the modulation of the coil current sustaining the PMITP for complete evaporation of the injected powder. Synthesized particles by the developed method were analyzed by FE-SEM and XRD. Results indicated that the synthesized particles by the 20-kW PMITP with a heavy loading rate of 12.3 g min −1 had a similar particle size distribution with the mean diameter about 40 nm to those with light loading of 4.2 g min −1 .

  13. In-pile measurement of the thermal conductivity of irradiated metallic fuel

    International Nuclear Information System (INIS)

    Bauer, T.H.; Holland, J.W.

    1995-01-01

    Transient test data and posttest measurements from recent in-pile overpower transient experiments are used for an in situ determination of metallic fuel thermal conductivity. For test pins that undergo melting but remain intact, a technique is described that relates fuel thermal conductivity to peak pin power during the transient and a posttest measured melt radius. Conductivity estimates and their uncertainty are made for a database of four irradiated Integral Fast Reactor-type metal fuel pins of relatively low burnup (<3 at.%). In the assessment of results, averages and trends of measured fuel thermal conductivity are correlated to local burnup. Emphasis is placed on the changes of conductivity that take place with burnup-induced swelling and sodium logging. Measurements are used to validate simple empirically based analytical models that describe thermal conductivity of porous media and that are recommended for general thermal analyses of irradiated metallic fuel

  14. Visualization and measurement by image processing of thermal hydraulic phenomena by neutron radiography

    International Nuclear Information System (INIS)

    Takenaka, Nobuyuki

    1996-01-01

    Neutron Radiography was applied to visualization of thermal hydraulic phenomena and measurement was carried out by image processing the visualized images. Since attenuation of thermal neutron rays is high in ordinary liquids like water and organic fluid while it is low in most of metals, liquid flow behaviors can be visualized through a metallic wall by neutron radiography. Measurement of void fraction and flow vector field which is important to study thermal hydraulic phenomena can be carried out by image processing the images obtained by the visualization. Various two-phase and liquid metal flows were visualized by a JRR-3M thermal neutron radiography system in the present study. Multi-dimensional void fraction distributions in two-phase flows and flow vector fields in liquid metals, which are difficult to measure by the other methods, were successfully measured by image processing. It was shown that neutron radiography was efficiently applicable to study thermal hydraulic phenomena. (author)

  15. Bond strength and stress measurements in thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M.; Jordan, E. [Univ. of Connecticut, Storrs, CT (United States)

    1995-10-01

    Thermal barrier coatings have been used extensively in aircraft gas turbines for more than 15 years to insulate combustors and turbine vanes from the hot gas stream. Plasma sprayed thermal barrier coatings (TBCs) provide metal temperature reductions as much as 300{degrees}F, with improvements in durability of two times or more being achieved. The introduction of TBCs deposited by electron beam physical vapor deposition (EB-PVD) processes in the last five years has provided a major improvement in durability and also enabled TBCs to be applied to turbine blades for improved engine performance. To meet the aggressive Advanced Turbine Systems goals for efficiency, durability and the environment, it will be necessary to employ thermal barrier coatings on turbine airfoils and other hot section components. For The successful application of TBCs to ATS engines with 2600{degrees}F turbine inlet temperatures and required component lives 10 times greater than those for aircraft gas turbine engines, it is necessary to develop quantitative assessment techniques for TBC coating integrity with time and cycles in ATS engines. Thermal barrier coatings in production today consist of a metallic bond coat, such as an MCrAlY overlay coating or a platinum aluminide (Pt-Al) diffusion coating. During heat treatment, both these coatings form a thin, tightly adherent alumina (Al{sub 2}O{sub 3}) film. Failure of TBC coatings in engine service occurs by spallation of the ceramic coating at or near the bond coat to alumina or the alumina to zirconia bonds. Thus, it is the initial strength of these bonds and the stresses at the bond plane, and their changes with engine exposure, that determines coating durability. The purpose of this program is to provide, for the first time, a quantitative assessment of TBC bond strength and bond plane stresses as a function of engine time and cycles.

  16. Nanoscale Electromechanics To Measure Thermal Conductivity, Expansion, and Interfacial Losses.

    Science.gov (United States)

    Mathew, John P; Patel, Raj; Borah, Abhinandan; Maliakkal, Carina B; Abhilash, T S; Deshmukh, Mandar M

    2015-11-11

    We study the effect of localized Joule heating on the mechanical properties of doubly clamped nanowires under tensile stress. Local heating results in systematic variation of the resonant frequency; these frequency changes result from thermal stresses that depend on temperature dependent thermal conductivity and expansion coefficient. The change in sign of the linear expansion coefficient of InAs is reflected in the resonant response of the system near a bath temperature of 20 K. Using finite element simulations to model the experimentally observed frequency shifts, we show that the thermal conductivity of a nanowire can be approximated in the 10-60 K temperature range by the empirical form κ = bT W/mK, where the value of b for a nanowire was found to be b = 0.035 W/mK(2), significantly lower than bulk values. Also, local heating allows us to independently vary the temperature of the nanowire relative to the clamping points pinned to the bath temperature. We suggest a loss mechanism (dissipation ~10(-4)-10(-5)) originating from the interfacial clamping losses between the metal and the semiconductor nanostructure.

  17. Alkyl side chain on the 1-methylimidazolium ring of countercation modulating thermal and magnetic properties of metal-dithiolene complexes

    Science.gov (United States)

    Duan, Hai-Bao; Yu, Shan-Shan; Cai, Ying; Zhang, Hui

    2015-05-01

    Two low-dimensional ion-pair compounds [1,5-bis(1-methylimidazolium)pentane][Ni(mnt)2]2 (1) and [1,9-bis(1-methylimidazolium)nonane][Ni(mnt)2]2 (2) (mnt2- = maleonitriledithiolate) were designed and synthesized. The cations and anions formed mixed column along the crystallographic a-axis direction in the crystal of 1·0.5DMF. Two compounds display different thermal and magnetic behaviors. Multi-step solid to solid state phase transition was observed for 1 by DSC. 1 exhibits weak paramagnetism over the temperature range of 2-400 K and 2 shows spin gap in the low-temperature phase. Thus by changing of the alky chain length of the counter-cation allows the modulation thermal and magnetic behaviors for such system.

  18. Development of a direct push based in-situ thermal conductivity measurement system

    Science.gov (United States)

    Chirla, Marian Andrei; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

    2016-04-01

    Heat pump systems are commonly utilized in Europe, for the exploitation of the shallow geothermal potential. To guarantee a sustainable use of the geothermal heat pump systems by saving resources and minimizing potential negative impacts induced by temperature changes within soil and groundwater, new geothermal exploration methods and tools are required. The knowledge of the underground thermal properties is a necessity for a correct and optimum design of borehole heat exchangers. The most important parameter that indicates the performance of the systems is thermal conductivity of the ground. Mapping the spatial variability of thermal conductivity, with high resolution in the shallow subsurface for geothermal purposes, requires a high degree of technical effort to procure adequate samples for thermal analysis. A collection of such samples from the soil can disturb sample structure, so great care must be taken during collection to avoid this. Factors such as transportation and sample storage can also influence measurement results. The use of technologies like Thermal Response Test (TRT) require complex mechanical and electrical systems for convective heat transport in the subsurface and longer monitoring times, often three days. Finally, by using thermal response tests, often only one integral value is obtained for the entire coupled subsurface with the borehole heat exchanger. The common thermal conductivity measurement systems (thermal analyzers) can perform vertical thermal conductivity logs only with the aid of sample procurement, or by integration into a drilling system. However, thermal conductivity measurements using direct push with this type of probes are not possible, due to physical and mechanical limitations. Applying vertical forces using direct push technology, in order to penetrate the shallow subsurface, can damage the probe and the sensors systems. The aim of this study is to develop a new, robust thermal conductivity measurement probe, for direct

  19. Thermal analysis of a helium-cooled, tube-bank blanket module for a tandem mirror fusion reactor

    International Nuclear Information System (INIS)

    Werner, R.W.

    1983-01-01

    A blanket module concept for the central cell of a tandem mirror reactor is described which takes advantage of the excellent heat transfer and low pressure drop characteristics of tube banks in cross-flow. The blanket employs solid Li 2 O as the tritium breeding material and helium as the coolant. The lithium oxide is contained in tubes arranged within the submodules as a two-pass, cross-flow heat exchanger. Primarily, the heat transfer and thermal-hydraulic aspects of the blanket design study are described in this paper. In particular, the analytical model used for selection of the best tube-bank design parameters is discussed in some detail

  20. Thermal analysis of a helium-cooled, tube-bank blanket module for a tandem-mirror fusion reactor

    International Nuclear Information System (INIS)

    Werner, R.W.; Hoffman, M.A.; Johnson, G.L.

    1983-01-01

    A blanket module concept for the central cell of a tandem mirror reactor is described which takes advantage of the excellent heat transfer and low pressure drop characteristics of tube banks in cross-flow. The blanket employs solid Li 2 O as the tritium breeding material and helium as the coolant. The lithium oxide is contained in tubes arranged within the submodules as a two-pass, cross-flow heat exchanger. Primarily, the heat transfer and thermal-hydraulic aspects of the blanket design study are described in this paper. In particular, the analytical model used for selection of the best tube-bank design parameters is discussed in some detail

  1. Verification of the thermal module in the ELESIM code and the associated uncertainty analysis

    International Nuclear Information System (INIS)

    Arimescu, V.I.; Williams, A.F.; Klein, M.E.; Richmond, W.R.; Couture, M.

    1997-09-01

    Temperature is a critical parameter in fuel modelling because most of the physical processes that occur in fuel elements during irradiation are thermally activated. The focus of this paper is the temperature distribution calculation used in the computer code ELESIM, developed at AECL to model the steady-state behaviour of CANDU fuel. A validation procedure for fuel codes is described and applied to ELESIM's thermal calculation.The effects of uncertainties in model parameters, like Uranium Dioxide thermal conductivity, and input variables, such as fuel element linear power, are accounted for through an uncertainty analysis using Response Surface and Monte Carlo techniques

  2. Phonon scattering and thermal conductance properties in two coupled graphene nanoribbons modulated with bridge atoms

    International Nuclear Information System (INIS)

    Tan, Shi-Hua; Tang, Li-Ming; Chen, Ke-Qiu

    2014-01-01

    The phonon scattering and thermal conductance properties have been studied in two coupled graphene nanoribbons connected by different bridge atoms by using density functional theory in combination with non-equilibrium Green's function approach. The results show that a wide range of thermal conductance tuning can be realized by changing the chemical bond strength and atom mass of the bridge atoms. It is found that the chemical bond strength (bridge atom mass) plays the main role in phonon scattering at low (high) temperature. A simple equation is presented to describe the relationship among the thermal conductance, bridge atom, and temperature.

  3. Parameter Estimation of the Thermal Network Model of a Machine Tool Spindle by Self-made Bluetooth Temperature Sensor Module

    Directory of Open Access Journals (Sweden)

    Yuan-Chieh Lo

    2018-02-01

    Full Text Available Thermal characteristic analysis is essential for machine tool spindles because sudden failures may occur due to unexpected thermal issue. This article presents a lumped-parameter Thermal Network Model (TNM and its parameter estimation scheme, including hardware and software, in order to characterize both the steady-state and transient thermal behavior of machine tool spindles. For the hardware, the authors develop a Bluetooth Temperature Sensor Module (BTSM which accompanying with three types of temperature-sensing probes (magnetic, screw, and probe. Its specification, through experimental test, achieves to the precision ±(0.1 + 0.0029|t| °C, resolution 0.00489 °C, power consumption 7 mW, and size Ø40 mm × 27 mm. For the software, the heat transfer characteristics of the machine tool spindle correlative to rotating speed are derived based on the theory of heat transfer and empirical formula. The predictive TNM of spindles was developed by grey-box estimation and experimental results. Even under such complicated operating conditions as various speeds and different initial conditions, the experiments validate that the present modeling methodology provides a robust and reliable tool for the temperature prediction with normalized mean square error of 99.5% agreement, and the present approach is transferable to the other spindles with a similar structure. For realizing the edge computing in smart manufacturing, a reduced-order TNM is constructed by Model Order Reduction (MOR technique and implemented into the real-time embedded system.

  4. Thermal management of cylindrical power battery module for extending the life of new energy electric vehicles

    International Nuclear Information System (INIS)

    Zhao, Jiateng; Rao, Zhonghao; Huo, Yutao; Liu, Xinjian; Li, Yimin

    2015-01-01

    Thermal management especially cooling plays an important role in power battery modules for electric vehicles. In order to comprehensively understand the heat transfer characteristics of air cooling system, the air cooling numerical simulation battery models for cylindrical lithium-ion power battery pack were established in this paper, and a detailed parametric investigation was undertaken to study effects of different ventilation types and velocities, gap spacing between neighbor batteries, temperatures of environment and entrance air, amount of single row cells and battery diameter on the thermal management performance of battery pack. The results showed that the local temperature difference increased firstly and then decreased with the increase of wind speed. Reversing the air flow direction between adjacent rows is not necessarily appropriate and the gap spacing should not be too small and too large. It is prone to thermal runaway when the ambient temperature is too high, and the most suitable value of S/D (the ratio of spacing distance between neighbor cells and cell diameter) is gradually reduced along with the increase of cell diameter. - Highlights: • Air cooling models were established for cylindrical lithium-ion power battery pack. • Local temperature difference increased firstly and then decreased with wind speed. • The gap spacing size of battery pack should not be too small and too large. • It is prone to thermal runaway when the ambient temperature is too high. • The ratio of S/D is gradually reduced with the increase of cell diameter

  5. A detailed thermal-electrical model of three photovoltaic/thermal (PV/T) hybrid air collectors and photovoltaic (PV) module: Comparative study under Algiers climatic conditions

    International Nuclear Information System (INIS)

    Slimani, Mohamed El Amine; Amirat, Madjid; Kurucz, Ildikó; Bahria, Sofiane; Hamidat, Abderrahmane; Chaouch, Wafa Braham

    2017-01-01

    Highlights: • A detailed thermal and electrical model for PV and PV/T systems has been presented. • The developed numerical model was validated successfully with previously published experimental results. • A comparative study between four solar devices (PV and PV/T systems) was carried out. • The experimental weather conditions of Algiers site are used in the numerical model. • The glazed double-pass photovoltaic/thermal air collector shows the best overall energy efficiency. - Abstract: The thermal photovoltaic hybrid collector is a genuine cogeneration technology; it can produce electricity and heat simultaneously. In this paper, a comparative study is presented between four solar device configurations: photovoltaic module (PV-I), conventional hybrid solar air collector (PV/T-II), glazed hybrid solar air collector (PV/T-III) and glazed double-pass hybrid solar air collector (PV/T-IV). A numerical model is developed and validated through experimental results indicated in the previous literature. The numerical model takes the heat balance equations and different thermal and electrical parameters into account for each configuration included in this study, the energy performances are evaluated with a sample weather data of Algiers site. The numerical results show that the daily average of overall energy efficiency reaches: 29.63%, 51.02%, 69.47% and 74% for the first (PV-I), the second (PV/T-II), the third (PV/T-III) and the fourth (PV/T-IV) configurations respectively. These values are obtained with an air flow of 0.023 kg/s and introducing a sample of experimental weather data collected in Algiers site for a sunny day in summer.

  6. Thermal conductivity measurement of the He-ion implanted layer of W using transient thermoreflectance technique

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Shilian; Li, Yuanfei [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, Zhigang [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Jia, Yuzhen [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu 610213 (China); Li, Chun [School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144 (China); Xu, Ben; Chen, Wanqi [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bai, Suyuan [School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Huang, Zhengxing; Tang, Zhenan [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-02-15

    Transient thermoreflectance method was applied on the thermal conductivity measurement of the surface damaged layer of He-implanted tungsten. Uniform damages tungsten surface layer was produced by multi-energy He-ion implantation with thickness of 450 nm. Result shows that the thermal conductivity is reduced by 90%. This technique was further applied on sample with holes on the surface, which was produced by the He-implanted at 2953 K. The thermal conductivity decreases to 3% from the bulk value.

  7. Temperature-Modulated Radiative Coatings for Dynamic Thermal Management of Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — During the course of its mission, a spacecraft is often exposed to significant thermal cycling. Hardware components, such as batteries, transmitters, etc. will only...

  8. Verification of the thermal module in the ELESIM code and the associated uncertainty analysis

    International Nuclear Information System (INIS)

    Arimescu, V.I.; Williams, A.F.; Klein, M.E.; Richmond, W.R.; Couture, M.

    1997-01-01

    Temperature is a critical parameter in fuel modelling because most of the physical processes that occur in fuel elements during irradiation are thermally activated. The focus of this paper is the temperature distribution calculation used in the computer code ELESIM, developed at AECL to model the steady state behaviour of CANDU fuel. A validation procedure for fuel codes is described and applied to ELESIM's thermal calculation

  9. Improving the thermal efficiency of a jaggery production module using a fire-tube heat exchanger.

    Science.gov (United States)

    La Madrid, Raul; Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel

    2017-12-15

    Jaggery is a product obtained after heating and evaporation processes have been applied to sugar cane juice via the addition of thermal energy, followed by the crystallisation process through mechanical agitation. At present, jaggery production uses furnaces and pans that are designed empirically based on trial and error procedures, which results in low ranges of thermal efficiency operation. To rectify these deficiencies, this study proposes the use of fire-tube pans to increase heat transfer from the flue gases to the sugar cane juice. With the aim of increasing the thermal efficiency of a jaggery installation, a computational fluid dynamic (CFD)-based model was used as a numerical tool to design a fire-tube pan that would replace the existing finned flat pan. For this purpose, the original configuration of the jaggery furnace was simulated via a pre-validated CFD model in order to calculate its current thermal performance. Then, the newly-designed fire-tube pan was virtually replaced in the jaggery furnace with the aim of numerically estimating the thermal performance at the same operating conditions. A comparison of both simulations highlighted the growth of the heat transfer rate at around 105% in the heating/evaporation processes when the fire-tube pan replaced the original finned flat pan. This enhancement impacted the jaggery production installation, whereby the thermal efficiency of the installation increased from 31.4% to 42.8%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Measuring proton beam thermal noises on the NAP-M storage ring

    International Nuclear Information System (INIS)

    Dement'ev, E.N.; Dikanskij, N.S.; Medvedko, A.S.; Parkhomchuk, V.V.; Pestrikov, D.V.

    1980-01-01

    The data on experimental investigation of thermal noises of an asimuthally homogeneous proton beam on the NAP-M storage ring are given. The noise spectra are measured at the 5th and 8th harmonics of the ciculation frequency using pick-up electrodes. The dependencies of the noise power on the proton current for noncooled and cooled beams are presented. It is shown that as a result of electron cooling the noise power decreases by two orders and in the 0.5-10 μA current range the noise power of the cooled beam does not depend on the proton current. The noise power of the noncooled beam linearly increases with the proton current. It is also shown that with the modulation growth the noise power increases. The conclusions are made that while analyzing noises of the continuous beam in the storage ring the changes of the noise spectra due to particle interaction in the beam should be taken into account

  11. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    International Nuclear Information System (INIS)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-01-01

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm 2 and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO 2 lasers

  12. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    Energy Technology Data Exchange (ETDEWEB)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-10-18

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm{sup 2} and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO{sub 2} lasers.

  13. Initial Measurements on Pixel Detector Modules for the ATLAS Upgrades

    CERN Document Server

    Gallrapp, C; The ATLAS collaboration

    2011-01-01

    Delicate conditions in terms of peak and integrated luminosity in the Large Hadron Collider (LHC) will raise the ATLAS Pixel Detector to its performance limits. Silicon planar, silicon 3D and diamond pixel sensors are three possible sensor technologies which could be implemented in the upcoming Pixel Detector upgrades of the ATLAS experiment. Measurements of the IV-behavior and measurements with radioactive Americium-241 and Strontium-90 are used to characterize the sensor properties and to understand the interaction between the ATLAS FE-I4 front-end chip and the sensor. Comparisons of results from before and after irradiation for silicon planar and 3D pixel sensors, which give a first impression on the charge collection properties of the different sensor technologies, are presented.

  14. Initial Measurements On Pixel Detector Modules For The ATLAS Upgrades

    CERN Document Server

    Gallrapp, C; The ATLAS collaboration

    2011-01-01

    Sophisticated conditions in terms of peak and integrated luminosity in the Large Hadron Collider (LHC) will raise the ATLAS Pixel detector to its performance limits. Silicon planar, silicon 3D and diamond pixel sensors are three possible sensor technologies which could be implemented in the upcoming pixel detector upgrades of the ATLAS experiment. Measurements of the IV-behavior and measurements with radioactive Americium-241 and Strontium-90 are used to characterize the sensor properties and to understand the interaction between the ATLAS FE-I4 front-end chip and the sensor. Comparisons of results from before and after irradiation, which give a first impression on the charge collection properties of the different sensor technologies are presented.

  15. Measurement of elastic modules of structural ceramic by acoustic resonance

    International Nuclear Information System (INIS)

    Ahn, Bong Young; Lee Seong Suck; Kim, Young Gil

    1993-01-01

    Elastic moduli of structural ceramic materials, Al 2 O 3 , SiC, Si 3 N 4 , were measured by acoustic resonance method. Young's modulus, shear modulus, and Poisson's ratio were calculated from the torsional and flexural resonant frequencies, densities, and the dimensions of the specimen. The results by acoustic resonance method were compared with the results by ultrasonic method and the differences were less than 4%.

  16. Hydrocarbon Fuel Thermal Performance Modeling based on Systematic Measurement and Comprehensive Chromatographic Analysis

    Science.gov (United States)

    2016-07-31

    distribution unlimited Hydrocarbon Fuel Thermal Performance Modeling based on Systematic Measurement and Comprehensive Chromatographic Analysis Matthew...vital importance for hydrocarbon -fueled propulsion systems: fuel thermal performance as indicated by physical and chemical effects of cooling passage... analysis . The selection and acquisition of a set of chemically diverse fuels is pivotal for a successful outcome since test method validation and

  17. Thermal modelling of the calorimeter used for energy measurement of LMJ laser pulse

    Directory of Open Access Journals (Sweden)

    Crespy C.

    2013-11-01

    Full Text Available In this work, a 3D thermal model of the LMJ calorimeter is developed using Comsol multiphysics. The unknown thermal properties of the system are identified by comparing the model results with the measured temperature. Several model's applications, such as comparing deposition modes (electrical and optical or defining calibration procedure, are presented.

  18. Measurement of the thermal diffusivity on ceramics and metals using the laser flash method

    International Nuclear Information System (INIS)

    Blumm, J.; Sauseng, B.

    2001-01-01

    Full Text: In the past few decades measurement of the thermophysical properties such as thermal expansion, specific heat, thermal diffusivity or thermal conductivity has become increasingly important for industrial applications. One example is the optimization of the heat transfer in industrial assemblies used for automotive or space applications. The thermal diffusivity and thermal conductivity of all components exposed to high and/or sub-ambient temperatures or large temperature gradients should be accurately known. Another well known example is the characterization of materials such as graphite used in nuclear reactors. Furthermore, analysis of solid and liquid metals is of paramount importance for the simulation of casting processes using finite element software programs. Thermal barrier coatings (zirconia) are used more and more often for high-temperature turbine blades. Reducing the thermal conductivity and the heat transfer through such coatings usually allows higher working temperatures and therefore higher efficiency of the gas turbine. These examples clearly demonstrate the need of instrumentation for the accurate measurement of the required thermophysical properties. The laser flash method has been developed to become one of the most commonly used techniques for the measurement of the thermal diffusivity of various kinds of solids and liquids. Easy sample preparation, small sample dimensions, fast measurement times and high accuracy are only some of the advantages of this non-destructive measurement technique. In addition, temperature dependent measurements can easily be realized. Since the development of the method by Parker et al. new routines for processing of the raw data have been established. Analytical mathematical descriptions were found to compensate for heat loss and finite pulse effects. Using modern personal computers and non-linear regression routines, mathematical models can be used to fit the raw data, yielding improved results for thermal

  19. Innovative measuring system for wear-out indication of high power IGBT modules

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup; Due, Jens; Munk-Nielsen, Stig

    2011-01-01

    Power converter failures are a major issue in modern Wind turbines. One of the key elements of power converters for high power application is the IGBT modules. A test bench capable of performing an accelerated wear-out test through power cycling of IGBT modules has been made. In the test bench...... it is possible to stress the IGBT module in a real life working point, controlling the voltage, current and phase of the device under test. An analysis of failure mechanisms has been carried out, indicating that VCE can be used as an sign of wear out of the IGBT module. Therefore an innovative measuring system...... for VCE monitoring with an accuracy as low as a few mV has been implemented. The measurements on the IGBT in the test bench show that it is possible to monitor VCE and use this as an indicator of wear-out....

  20. Measurement with SR-0 experimental modules of the SPHINX nuclear transmutation system. Variants 2008

    International Nuclear Information System (INIS)

    Rypar, Vojtech; Juricek, Vlastimil; Svadlenkova, Marie; Heraltova, Lenka; Viererbl, Ladislav; Lahodova, Zdena

    2008-12-01

    Experiments were performed with two LR-0 rector core arrangements and 3 variants of SR-0 insertion modules with a view to establishing the critical parameters of the reactor cores for the 3 module variants comprising different materials and different numbers of LR-0 fuel pins. The effect of the materials on the photon dose distribution and, on the axial and radial neutron field distributions (via 140 Ba and 140 La activities) was examined and the reaction rate distribution of activation foils inside the experimental module was measured

  1. Network module detection: Affinity search technique with the multi-node topological overlap measure.

    Science.gov (United States)

    Li, Ai; Horvath, Steve

    2009-07-20

    Many clustering procedures only allow the user to input a pairwise dissimilarity or distance measure between objects. We propose a clustering method that can input a multi-point dissimilarity measure d(i1, i2, ..., iP) where the number of points P can be larger than 2. The work is motivated by gene network analysis where clusters correspond to modules of highly interconnected nodes. Here, we define modules as clusters of network nodes with high multi-node topological overlap. The topological overlap measure is a robust measure of interconnectedness which is based on shared network neighbors. In previous work, we have shown that the multi-node topological overlap measure yields biologically meaningful results when used as input of network neighborhood analysis. We adapt network neighborhood analysis for the use of module detection. We propose the Module Affinity Search Technique (MAST), which is a generalized version of the Cluster Affinity Search Technique (CAST). MAST can accommodate a multi-node dissimilarity measure. Clusters grow around user-defined or automatically chosen seeds (e.g. hub nodes). We propose both local and global cluster growth stopping rules. We use several simulations and a gene co-expression network application to argue that the MAST approach leads to biologically meaningful results. We compare MAST with hierarchical clustering and partitioning around medoid clustering. Our flexible module detection method is implemented in the MTOM software which can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/MTOM/

  2. Experimental Investigation on Thermal Management of Electric Vehicle Battery Module with Paraffin/Expanded Graphite Composite Phase Change Material

    Directory of Open Access Journals (Sweden)

    Jiangyun Zhang

    2017-01-01

    Full Text Available The temperature has to be controlled adequately to maintain the electric vehicles (EVs within a safety range. Using paraffin as the heat dissipation source to control the temperature rise is developed. And the expanded graphite (EG is applied to improve the thermal conductivity. In this study, the paraffin and EG composite phase change material (PCM was prepared and characterized. And then, the composite PCM have been applied in the 42110 LiFePO4 battery module (48 V/10 Ah for experimental research. Different discharge rate and pulse experiments were carried out at various working conditions, including room temperature (25°C, high temperature (35°C, and low temperature (−20°C. Furthermore, in order to obtain the practical loading test data, a battery pack with the similar specifications by 2S∗2P with PCM-based modules were installed in the EVs for various practical road experiments including the flat ground, 5°, 10°, and 20° slope. Testing results indicated that the PCM cooling system can control the peak temperature under 42°C and balance the maximum temperature difference within 5°C. Even in extreme high-discharge pulse current process, peak temperature can be controlled within 50°C. The aforementioned results exhibit that PCM cooling in battery thermal management has promising advantages over traditional air cooling.

  3. Dynamic Efficiency Measurements for Irradiated ATLAS Pixel Single Chip Modules

    CERN Document Server

    Pfaff, Mike; Grosse-Knetter, Jorn

    2011-01-01

    The ATLAS pixel detector is the innermost subdetector of the ATLAS experiment. Due to this, the pixel detector has to be particularly radiation hard. In this diploma thesis effects on the sensor and the electronics which are caused by irradiation are examined. It is shown how the behaviour changes between an unirradiated sample and a irradiated sample, which was treated with the same radiation dose that is expected at the end of the lifetime of ATLAS. For this study a laser system, which is used for dynamic efficiency measurements was constructed. Furthermore, the behaviour of the noise during the detection of a particle was evaluated studied.

  4. Space station common module thermal management: Design and construction of a test bed

    Science.gov (United States)

    Barile, R. G.

    1986-01-01

    In this project, a thermal test bed was designed, simulated, and planned for construction. The thermal system features interior and exterior thermal loads and interfacing with the central-radiator thermal bus. Components of the test bed include body mounted radiator loop with interface heat exchangers (600 Btu/hr); an internal loop with cabin air-conditioning and cold plates (3400 Btu/hr); interface heat exchangers to the central bus (13,000 Btu/hr); and provisions for new technology including advanced radiators, thermal storage, and refrigeration. The apparatus will be mounted in a chamber, heated with lamps, and tested in a vacuum chamber with LN2-cooled walls. Simulation of the test bed was accomplished using a DEC PRO 350 computer and the software package TK! olver. Key input variables were absorbed solar radiation and cold plate loads. The results indicate temperatures on the two loops will be nominal when the radiation and cold plate loads are in the range of 25% to 75% of peak loads. If all loads fall to zero, except the cabin air system which was fixed, the radiator fluid will drop below -100 F and may cause excessive pressure drop. If all loads reach 100%, the cabin air temperature could rise to 96 F.

  5. Measuring and assessing the effective in-plane thermal conductivity of lithium iron phosphate pouch cells

    International Nuclear Information System (INIS)

    Bazinski, S.J.; Wang, X.; Sangeorzan, B.P.; Guessous, L.

    2016-01-01

    The objective of this research is to experimentally determine the effective in-plane thermal conductivity of a lithium iron phosphate pouch cell. An experimental setup is designed to treat the battery cell as a straight rectangular fin in natural convection. Thermography and heat sensors were used to collect data that yields the temperature distribution and heat transfer rate of the fin, respectively. One-dimensional fin equations were combined with the experimental data to yield the in-plane thermal conductivity through an iterative process that best-fits the data to the model. The experiment was first calibrated using reference plates of different metals. The fin model predicts the thermal conductivity value well with a correction factor of approximately 7%–9%. Using this experimental method, the in-plane thermal conductivity of the pouch cells is measured at different state of charge (SOC) levels. The in-plane thermal conductivity decreases approximately 0.13 Wm"−"1 °C"−"1 per 10% increase in SOC for the LFP cells. This translates to a 4.2% overall decrease in the thermal conductivity as the cell becomes fully charged. - Highlights: • A method is proposed to measure the in-plane thermal conductivity of a pouch cell. • The thermal conductivity decreases slightly with increase in SOC for the LFP cells. • The fin model predicts the thermal conductivity well with a correction factor.

  6. Penumbra measurements of BeamModulatorTM multi leaf collimator

    International Nuclear Information System (INIS)

    Lu Xiaoguang; Wang Yunlai; Huo Xiaoqing; Sha Xiangyan; Miao Xiongfei

    2010-01-01

    Objective: To evaluate the penumbra of a new multileaf collimator equipped with Elekta Synergy accelerator. Methods: The penumbra were derived from beam profiles measured in air and water using PinPoint ion chamber with PTW MP3 water phantom. Variations of penumbra with X-ray beam energy, depth in water, and leaf position were investigated. Results: The penumbra in air for 6 MV X-ray was 2 mm less than that at depth of maximal dose in water. The penumbra of leaf side was 1 mm less than that of the leaf end. The penumbra had close relationship with beam energy, depth in water and leaf position. penumbra increased with beam quality and water depth. The leaf position had great influence on the penumbra. Conclusions: The penumbra of the multileaf collimator is related to its original design and radiation delivery technique. Special considerations should be taken into during treatment planning. Regular measurement should be performed to guarantee the delivery quality. (authors)

  7. Thermal Diffusivity Measurement for p-Si and Ag/p-Si by Photoacoustic Technique

    Science.gov (United States)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi

    2015-10-01

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f c . In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm2/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon.

  8. Thermal diffusivity measurement for p-Si and Ag/p-Si by photoacoustic technique

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi, E-mail: mohammed55865@yahoo.com [Department of Physics, Faculty of Science, Universiti PutraMalaysia (UPM), Serdang (Malaysia)

    2015-10-15

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f{sub c.} In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm{sup 2}/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon. (author)

  9. New Technique for Luminosity Measurement Using 3D Pixel Modules in the ATLAS IBL Detector

    CERN Document Server

    Liu, Peilian; The ATLAS collaboration

    2017-01-01

    The Insertable b-Layer ( IBL ) is the innermost layer of the ATLAS tracking system. It consists of planar pixel modules in the central region and 3D modules at two extremities. We use the cluster length distributions in 3D sensor modules of the IBL to determine the number of primary charged particles per event and suppress backgrounds. This Pixel Cluster Counting ( PCC ) algorithm provides a bunch-by-bunch luminosity measurement. An accurate luminosity measurement is a key component for precision measurements at the Large Hadron Collider and one of the largest uncertainties on the luminosity determination in ATLAS arises from the long-term stability of the measurement technique. The comparison of the PCC algorithm with other existing algorithms provides key insights in assessing and reducing such uncertainty.

  10. Method for measuring retardation of infrared wave-plate by modulated-polarized visible light

    Science.gov (United States)

    Zhang, Ying; Song, Feijun

    2012-11-01

    A new method for precisely measuring the optical phase retardation of wave-plates in the infrared spectral region is presented by using modulated-polarized visible light. An electro-optic modulator is used to accurately determine the zero point by the frequency-doubled signal of the Modulated-polarized light. A Babinet-Soleil compensator is employed to make the phase delay compensation. Based on this method, an instrument is set up to measure the retardations of the infrared wave-plates with visible region laser. Measurement results with high accuracy and sound repetition are obtained by simple calculation. Its measurement precision is less than and repetitive precision is within 0.3%.

  11. Accurate and cost-effective MTF measurement system for lens modules of digital cameras

    Science.gov (United States)

    Chang, Gao-Wei; Liao, Chia-Cheng; Yeh, Zong-Mu

    2007-01-01

    For many years, the widening use of digital imaging products, e.g., digital cameras, has given rise to much attention in the market of consumer electronics. However, it is important to measure and enhance the imaging performance of the digital ones, compared to that of conventional cameras (with photographic films). For example, the effect of diffraction arising from the miniaturization of the optical modules tends to decrease the image resolution. As a figure of merit, modulation transfer function (MTF) has been broadly employed to estimate the image quality. Therefore, the objective of this paper is to design and implement an accurate and cost-effective MTF measurement system for the digital camera. Once the MTF of the sensor array is provided, that of the optical module can be then obtained. In this approach, a spatial light modulator (SLM) is employed to modulate the spatial frequency of light emitted from the light-source. The modulated light going through the camera under test is consecutively detected by the sensors. The corresponding images formed from the camera are acquired by a computer and then, they are processed by an algorithm for computing the MTF. Finally, through the investigation on the measurement accuracy from various methods, such as from bar-target and spread-function methods, it appears that our approach gives quite satisfactory results.

  12. Calorimetric Measurement for Internal Conversion Efficiency of Photovoltaic Cells/Modules Based on Electrical Substitution Method

    Science.gov (United States)

    Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato

    2018-02-01

    We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.

  13. Thermal strain measurements in graphite using electronic speckle pattern interferometry

    International Nuclear Information System (INIS)

    Tamulevicius, S.; Augulis, L.; Augulis, R.; Zabarskas, V.; Levinskas, R.; Poskas, P.

    2001-01-01

    Two 1500 MW(e) RBMK Units are operated at Ignalina NPP in Lithuania. Due to recent decision of the Parliament on the earlier closure of Unit 1, preparatory work for decommissioning have been initiated. Preferred decommissioning strategy is based on delayed dismantling after rather long safe enclosure period. Since graphite is one of the basic and probably the most voluminous components of the reactor internals, a sufficient information on status and behaviour of graphite moderator and reflector during long time safe enclosure period is of special significance. In this context, thermal strain in graphite is one of the parameters requiring particular interest. Electronic speckle pattern interferometry has been proposed and successfully tested to control this parameter using the real samples of graphite from Ignalina NPP Units. (author)

  14. Design and implementation of VUV-CD and LD measurements using an ac modulated polarizing undulator

    International Nuclear Information System (INIS)

    Yagi-Watanabe, K.; Yamada, T.; Tanaka, M.; Kaneko, F.; Kitada, T.; Ohta, Y.; Nakagawa, K.

    2005-01-01

    VUV circular dichroism (CD) and linear dichroism (LD) have been successfully measured at wavelengths beyond the conventional limit by using an ac modulated polarizing undulator. We have developed CD and LD measuring technique by polarization modulation at the source, without using transmission type polarizing modulator, to extend to the coverage to wavelengths shorter than 140-bar nm. AIST developed in 1986 ac polarizing undulator by using a electron storage ring 'TERAS' based on an original concept. The undulator which can produce any desired polarization of vertical- and horizontal-linear polarization (VLP and HLP) and right- and left-handed circular polarization (RCP and LCP) is specially well suited to both measurements of CD and LD. With this undulator, the polarization alternate in the order of VLP-RCP-HLP-RCP-VLP-LCP-HLP-LCP-VLP-, i.e. when circular polarization is modulated in f Hz, linear polarization alters in 2f Hz. This allows us simultaneous measurements of CD and LD. Since the TERAS can produce ac-modulated polarized radiation of wavelength as short as 40-bar nm, it is expected to have CD and LD measurement extended to 40-bar nm

  15. Design of capacitance measurement module for determining critical cold temperature of tea leaves

    Directory of Open Access Journals (Sweden)

    Yongzong Lu

    2016-12-01

    Full Text Available Critical cold temperature is one of the most crucial control factors for crop frost protection. Tea leaf's capacitance has a significant response to cold injury and appears as a peak response to a typical low temperature which is the critical temperature. However, the testing system is complex and inconvenient. In view of these, a tea leaf's critical temperature detector based on capacitance measurement module was designed and developed to measure accurately and conveniently the capacitance. Software was also designed to measure parameters, record data, query data as well as data deletion module. The detector utilized the MSP430F149 MCU as the control core and ILI9320TFT as the display module, and its software was compiled by IAR5.3. Capacitance measurement module was the crucial part in the overall design which was based on the principle of oscillator. Based on hardware debugging and stability analysis of capacitance measurement module, it was found that the output voltage of the capacitance measurement circuit is stable with 0.36% average deviation. The relationship between capacitance and 1/Uc2 was found to be linear distribution with the determination coefficient above 0.99. The result indicated that the output voltage of capacitance measurement module well corresponded to the change in value of the capacitance. The measurement error of the circuit was also within the required range of 0 to 100 pF which meets the requirement of tea leaf's capacitance. Keywords: Tea leaves, Critical cold temperature, Capacitance peak response, Frost protection, Detector

  16. Simplified Thermal Modeling for IGBT Modules with Periodic Power Loss Profiles in Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Zhang, Yi; Wang, Huai; Wang, Zhongxu

    2018-01-01

    One of the future challenges in Modular Multilevel Converters (MMCs) is how to size key components with compromised costs and design margins while fulfilling specific reliability targets. It demands better thermal modeling compared to the state-of-the-art in terms of both accuracy and simplicity....... Different from two-level power converters, MMCs have inherent dc-bias in arm currents and the power device conduction time is affected by operational parameters. A time-wise thermal modeling for the power devices in MMCs is, therefore, an iteration process and time-consuming. This paper thus proposes...

  17. Microinverter Thermal Performance in the Real-World: Measurements and Modeling

    Science.gov (United States)

    Hossain, Mohammad Akram; Xu, Yifan; Peshek, Timothy J.; Ji, Liang; Abramson, Alexis R.; French, Roger H.

    2015-01-01

    Real-world performance, durability and reliability of microinverters are critical concerns for microinverter-equipped photovoltaic systems. We conducted a data-driven study of the thermal performance of 24 new microinverters (Enphase M215) connected to 8 different brands of PV modules on dual-axis trackers at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University, based on minute by minute power and thermal data from the microinverters and PV modules along with insolation and environmental data from July through October 2013. The analysis shows the strengths of the associations of microinverter temperature with ambient temperature, PV module temperature, irradiance and AC power of the PV systems. The importance of the covariates are rank ordered. A multiple regression model was developed and tested based on stable solar noon-time data, which gives both an overall function that predicts the temperature of microinverters under typical local conditions, and coefficients adjustments reecting refined prediction of the microinverter temperature connected to the 8 brands of PV modules in the study. The model allows for prediction of internal temperature for the Enphase M215 given similar climatic condition and can be expanded to predict microinverter temperature in fixed-rack and roof-top PV systems. This study is foundational in that similar models built on later stage data in the life of a device could reveal potential influencing factors in performance degradation. PMID:26147339

  18. Uncertainty analysis of thermal quantities measurement in a centrifugal compressor

    Science.gov (United States)

    Hurda, Lukáš; Matas, Richard

    2017-09-01

    Compressor performance characteristics evaluation process based on the measurement of pressure, temperature and other quantities is examined to find uncertainties for directly measured and derived quantities. CFD is used as a tool to quantify the influences of different sources of uncertainty of measurements for single- and multi-thermocouple total temperature probes. The heat conduction through the body of the thermocouple probe and the heat-up of the air in the intake piping are the main phenomena of interest.

  19. Absolute measurement of the thermal conductivity of insulating materials at high temperature

    International Nuclear Information System (INIS)

    Liermann, J.

    1975-01-01

    A device was developed at the CEA for the absolute measurement of the thermal conductivity of insulators. It can operate in controlled atmospheres (air, CO 2 , Ar, He) and between 100 and 1050 deg C [fr

  20. Thermal pulse measurements of space charge distributions under an applied electric field in thin films

    International Nuclear Information System (INIS)

    Zheng, Feihu; An, Zhenlian; Zhang, Yewen; Liu, Chuandong; Lin, Chen; Lei, Qingquan

    2013-01-01

    The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films. (paper)

  1. Self-consistent photothermal techniques: Application for measuring thermal diffusivity in vegetable oils

    Science.gov (United States)

    Balderas-López, J. A.; Mandelis, Andreas

    2003-01-01

    The thermal wave resonator cavity (TWRC) was used to measure the thermal properties of vegetable oils. The thermal diffusivity of six commercial vegetable oils (olive, corn, soybean, canola, peanut, and sunflower) was measured by means of this device. A linear relation between both the amplitude and phase as functions of the cavity length for the TWRC was observed and used for the measurements. Three significant figure precisions were obtained. A clear distinction between extra virgin olive oil and other oils in terms of thermal diffusivity was shown. The high measurement precision of the TWRC highlights the potential of this relatively new technique for assessing the quality of this kind of fluids in terms of their thermophysical properties.

  2. An optimised instrument to measure thermal diffusivities of gases with opto-acoustic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Soldner, J.; Stephan, K. [Institute of Technical Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, 70550, Stuttgart (Germany)

    2004-11-01

    The paper describes the theory and application of opto-acoustics to determine thermal diffusivities of gases. An experimental device, already described in previous papers of the authors [Internat. J. Thermophys. 19 (1998) 1099; Proc. 2. European Thermal Science and 14. UIT National Heat Transfer Conf., 1996, pp. 1071-1078] permitted the detection of thermal diffusivities of gases at moderate pressures with an experimental uncertainty of about {+-}1.25%.Based on the experience gained with this device, a comprehensive error analysis is presented in this paper. It shows how the experimental uncertainties can be considerably reduced to about -0.45 to +0.35%. The parameters for optical cell design are dealt with, as well as the appropriate characteristics, such as frequencies of the modulated laser beam, and the microphone used in the experiment. (authors)

  3. Research and development of thermal-fluid measuring instrument

    International Nuclear Information System (INIS)

    Tuzla, K.; Chen, J.C.

    1991-01-01

    The goal of this program is to develop an instrument to measure the time-fraction of liquid contact in the transition and film boiling regimes for flow within a vertical tube. The work was carried out at Lehigh University between February 15, 1989 to February 15, 1991. The instrument to measure time-fraction of liquid contact was successfully developed and tested

  4. Measuring transient high temperature thermal phenomena in hostile environment

    International Nuclear Information System (INIS)

    Brenden, B.B.; Hartman, J.S.; Reich, F.R.

    1980-01-01

    The design of equipment for measuring temperature and strain in a rapidly heated and pressurized cylinder of stainless steel is discussed. Simultaneous cinematography of the full circumference of the cylinder without interference with temperature and strain measurements is also illustrated. The integrated system uses a reflective chamber for the sample and requires careful consideration of the spectral energy distribution utilized by each instrument

  5. Diamond Thermal Expansion Measurement Using Transmitted X-ray Back-diffraction.

    OpenAIRE

    Giles, Carlos; Adriano, Cris; Lubambo, Adriana Freire; Cusatis, Cesar; Mazzaro, Irineu; Hönnicke, Marcelo Goncalves

    2015-01-01

    The linear thermal expansion coefficient of diamond has been measured using forward-diffracted profiles in X-ray backscattering. This experimental technique is presented as an alternative way of measuring thermal expansion coefficients of solids in the high-resolution Bragg backscattering geometry without the intrinsic difficulty of detecting the reflected beam. The temperature dependence of the lattice parameter is obtained from the high sensitivity of the transmitted profiles to the Bragg a...

  6. Thermal conductivity measurements in relation to the geothermal exploration of the Gorleben salt dome

    International Nuclear Information System (INIS)

    Kopietz, J.

    1985-01-01

    The results of thermal conductivity measurements on rock salt and associated structures are presented in this paper. Thermal conductivity data obtained from laboratory measurements on the core material are compared with high-precision temperature gradient logs from the exploration boreholes. This work is part of an extensive investigation into the suitability of the Gorleben salt done in northern Germany as a radioactive waste disposal site

  7. Simbol-X Mirror Module Thermal Shields: I-Design and X-Ray Transmission

    Science.gov (United States)

    Collura, A.; Barbera, M.; Varisco, S.; Basso, S.; Pareschi, G.; Tagliaferri, G.; Ayers, T.

    2009-05-01

    The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.

  8. Simbol-X Mirror Module Thermal Shields: I - Design and X-Ray Transmission

    International Nuclear Information System (INIS)

    Collura, A.; Varisco, S.; Barbera, M.; Basso, S.; Pareschi, G.; Tagliaferri, G.; Ayers, T.

    2009-01-01

    The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.

  9. Thermal Properties and Thermal Analysis:

    Science.gov (United States)

    Kasap, Safa; Tonchev, Dan

    The chapter provides a summary of the fundamental concepts that are needed to understand the heat capacity C P, thermal conductivity κ, and thermal expansion coefficient α L of materials. The C P, κ, and α of various classes of materials, namely, semiconductors, polymers, and glasses, are reviewed, and various typical characteristics are summarized. A key concept in crystalline solids is the Debye theory of the heat capacity, which has been widely used for many decades for calculating the C P of crystals. The thermal properties are interrelated through Grüneisen's theorem. Various useful empirical rules for calculating C P and κ have been used, some of which are summarized. Conventional differential scanning calorimetry (DSC) is a powerful and convenient thermal analysis technique that allows various important physical and chemical transformations, such as the glass transition, crystallization, oxidation, melting etc. to be studied. DSC can also be used to obtain information on the kinetics of the transformations, and some of these thermal analysis techniques are summarized. Temperature-modulated DSC, TMDSC, is a relatively recent innovation in which the sample temperature is ramped slowly and, at the same time, sinusoidally modulated. TMDSC has a number of distinct advantages compared with the conventional DSC since it measures the complex heat capacity. For example, the glass-transition temperature T g measured by TMDSC has almost no dependence on the thermal history, and corresponds to an almost step life change in C P. The new Tzero DSC has an additional thermocouple to calibrate better for thermal lags inherent in the DSC measurement, and allows more accurate thermal analysis.

  10. Measuring thermal conductivity of polystyrene nanowires using the dual-cantilever technique.

    Science.gov (United States)

    Canetta, Carlo; Guo, Samuel; Narayanaswamy, Arvind

    2014-10-01

    Thermal conductance measurements are performed on individual polystyrene nanowires using a novel measurement technique in which the wires are suspended between two bi-material microcantilever sensors. The nanowires are fabricated via electrospinning process. Thermal conductivity of the nanowire samples is found to be between 6.6 and 14.4 W m(-1) K(-1) depending on sample, a significant increase above typical bulk conductivity values for polystyrene. The high strain rates characteristic of electrospinning are believed to lead to alignment of molecular polymer chains, and hence the increase in thermal conductivity, along the axis of the nanowire.

  11. Studies on the under ground heating in greenhouse. Measuring of thermal conductivity of soil

    Energy Technology Data Exchange (ETDEWEB)

    Iwao, Toshio; Takeyama, Koichi

    1987-12-21

    The underground heating system is an effective method of heating a greenhouse, because the system controls directly the temperature of soil near the roots. The thermal conductivity of soil was measured by the steady-state method, and the heat transfer characteristics in soil were examined in this study. In measuring the thermal conductivity through experiments, firstly the thermal conductivity of a reference plate was measured by the steady-state method, then on the basis of the above mentioned result, the thermal conuctivity of soil was obtained by the comparative method. Toyoura standard sands with particle size of 0.21-0.25mm were used as the sample. As the experiment result, the relations between the thermal conductivity of the reference plate (glass) and temperature was made clear, furthermore through the measurements using these relations, it was clarified that the apparent thermal conductivity is influenced by soil water content. It seems that the difference between the apparent thermal conductivity and the real one is caused mainly by a migration of latent heat with a migration of steam. (10 figs, 7 refs)

  12. Estimation of thermal transmittance based on temperature measurements with the application of perturbation numbers

    Science.gov (United States)

    Nowoświat, Artur; Skrzypczyk, Jerzy; Krause, Paweł; Steidl, Tomasz; Winkler-Skalna, Agnieszka

    2018-05-01

    Fast estimation of thermal transmittance based on temperature measurements is uncertain, and the obtained results can be burdened with a large error. Nevertheless, such attempts should be undertaken merely due to the fact that a precise measurement by means of heat flux measurements is not always possible in field conditions (resentment of the residents during the measurements carried out inside their living quarters), and the calculation methods do not allow for the nonlinearity of thermal insulation, heat bridges or other fragments of building envelope of diversified thermal conductivity. The present paper offers the estimation of thermal transmittance and internal surface resistance with the use of temperature measurements (in particular with the use of thermovision). The proposed method has been verified through tests carried out on a laboratory test stand built in the open space, subjected to the influence of real meteorological conditions. The present elaboration involves the estimation of thermal transmittance by means of temperature measurements. Basing on the mentioned estimation, the authors present correction coefficients which have impact on the estimation accuracy. Furthermore, in the final part of the paper, various types of disturbance were allowed for using perturbation numbers, and the introduced by the authors "credibility area of thermal transmittance estimation" was determined.

  13. Thermal striping heat transfer measurements in sodium AKB experiments

    International Nuclear Information System (INIS)

    Sheriff, N.; Sephton, K.P.; Gleave, C.

    1988-01-01

    Temperature fluctuations are produced in the sodium flow of fast reactors where hot and cold flow streams mix. A sodium experiment mounted on the Interatom facility AKB has been used to measure the heat transfer conditions in a flow stream with typical temperature fluctuations. The measurements were made at locations near to the leading edge of a plate, where in practice the most severe conditions are expected. With tests carried out over a wide range of flows good correlations of the heat transfer data with flow have been obtained. A simple theoretical model is proposed to explain the magnitude of the measured heat transfer coefficients, and the use of reasonable assumptions in the model produce good agreement with the experimental measurements

  14. Ionic liquids-modulated two-phase thermal synthesis of three-dimensional CuS nanostructures

    International Nuclear Information System (INIS)

    Yao, Kaisheng; Lu, Weiwei; Li, Xinying; Wang, Jianji

    2012-01-01

    A novel method was proposed for successful fabrication of CuS nanostructures with various morphologies. At the ionic liquids (ILs)-modulated CHCl 3 –H 2 O interface, copper cupferronate [Cu(cup) 2 ] in CHCl 3 reacted with thiourea in water to generate CuS nanostructures via a solvothermal reaction process. The effects of alkyl chain length of imidazolium cations and nature of anions of the ILs, molar ratio of Cu(cup) 2 to thiourea, the reaction temperature and time on the morphology of the products were studied systematically. It was shown that by changing alkyl chain length of imidazolium cations and nature of anions of the ILs, CuS nanostructures with various morphologies, including flowers, urchins, large nanodisks and nanoparticles, could be obtained at the liquid–liquid interface, and the ILs played important template roles in directing the formation of CuS nanostructures. Furthermore, the as-prepared CuS samples exhibited high catalytic activity for photodegradation of methyl orange and thermal decomposition of ammonium perchlorate. - Graphical abstract: At the ionic liquids-modulated CHCl 3 –H 2 O interface, the CuS nanostructures with the various morphologies of flowers, urchins, large nanodisks and nanoparticles have been successfully prepared via a solvothermal reaction process. Highlights: ► The properties of oil–H 2 O interface can be modulated by employing different ILs. ► The modulated interface has been used to prepare CuS nanostructures with various morphologies. ► The CuS samples exhibited high catalytic activity for the photodegradation of methyl orange.

  15. Measurement of thermal expansion for a Li2TiO3 pebble bed

    International Nuclear Information System (INIS)

    Hisashi Tanigawa; Mikio Enoeda; Masato Akiba

    2006-01-01

    In the current design of the blanket with ceramic breeders, pebbles of breeding materials are packed into a container and used as a pebble bed. Thermal and mechanical conditions externally loaded on the bed affect thermal and mechanical properties of the bed. It is necessary to analyze thermo-mechanical properties of the bed under controlled thermal and mechanical conditions. In the present paper, thermal expansion of a Li 2 TiO 3 pebble bed was investigated. Our apparatus consists of a tensile test-apparatus and a measurement chamber. Pebbles of Li 2 TiO 3 with 2 mm diameter were used. They were packed into a container made of alumina. At first, thermal expansion of the apparatus was calibrated because the measured deformation included thermal expansions of the load rods and the container. Instead of the pebble bed, a column made of copper was installed and thermal expansion of the system was measured for the calibration. Taking into account the estimated thermal expansion of the column, thermal expansion of the rods and the container could be analyzed. Based on the correction, thermal expansion of the pebble bed was measured under compression of 0.1 MPa. Temperature of the bed was regulated from room temperature to 973 K. From the measured expansion of the bed, average thermal expansion coefficient was estimated. For the beds with different packing factors ranging from 65.5 to 68.5 %, thermal expansion coefficients were 1.4 ± 0. 10-5 K -1 . In the first measurement of the beds without pre-loading, expansion coefficients were larger for the cooling process than heating. When the beds were successively heated and cooled, the difference decreased. This means that relocation of the pebbles arises in the first heat treatment and progress of compaction is larger in the cooling process than heating. After a few heat treatments, packing states of the beds reach stable and expansion coefficients for both heat and cooling processes are close. In the case of the beds that

  16. Total uncertainty of low velocity thermal anemometers for measurement of indoor air movements

    DEFF Research Database (Denmark)

    Jørgensen, F.; Popiolek, Z.; Melikov, Arsen Krikor

    2004-01-01

    For a specific thermal anemometer with omnidirectional velocity sensor the expanded total uncertainty in measured mean velocity Û(Vmean) and the expanded total uncertainty in measured turbulence intensity Û(Tu) due to different error sources are estimated. The values are based on a previously...... developed mathematical model of the anemometer in combination with a large database of representative room flows measured with a 3-D Laser Doppler anemometer (LDA). A direct comparison between measurements with a thermal anemometer and a 3-D LDA in flows of varying velocity and turbulence intensity shows...... good agreement not only between the two instruments but also between the thermal anemometer and its mathematical model. The differences in the measurements performed with the two instruments are all well within the measurement uncertainty of both anemometers....

  17. Thin-film-based CdTe photovoltaic module characterization: measurements and energy prediction improvement.

    Science.gov (United States)

    Lay-Ekuakille, A; Arnesano, A; Vergallo, P

    2013-01-01

    Photovoltaic characterization is a topic of major interest in the field of renewable energy. Monocrystalline and polycrystalline modules are mostly used and, hence characterized since many laboratories have data of them. Conversely, cadmium telluride (CdTe), as thin-film module are, in some circumstances, difficult to be used for energy prediction. This work covers outdoor testing of photovoltaic modules, in particular that regarding CdTe ones. The scope is to obtain temperature coefficients that best predict the energy production. A First Solar (K-275) module has been used for the purposes of this research. Outdoor characterizations were performed at Department of Innovation Engineering, University of Salento, Lecce, Italy. The location of Lecce city represents a typical site in the South Italy. The module was exposed outdoor and tested under clear sky conditions as well as under cloudy sky ones. During testing, the global-inclined irradiance varied between 0 and 1500 W/m(2). About 37,000 I-V characteristics were acquired, allowing to process temperature coefficients as a function of irradiance and ambient temperature. The module was characterized by measuring the full temperature-irradiance matrix in the range from 50 to 1300 W/m(2) and from -1 to 40 W/m(2) from October 2011 to February 2012. Afterwards, the module energy output, under real conditions, was calculated with the "matrix method" of SUPSI-ISAAC and the results were compared with the five months energy output data of the same module measured with the outdoor energy yield facility in Lecce.

  18. Further elucidation of nanofluid thermal conductivity measurement using a transient hot-wire method apparatus

    Science.gov (United States)

    Yoo, Donghoon; Lee, Joohyun; Lee, Byeongchan; Kwon, Suyong; Koo, Junemo

    2018-02-01

    The Transient Hot-Wire Method (THWM) was developed to measure the absolute thermal conductivity of gases, liquids, melts, and solids with low uncertainty. The majority of nanofluid researchers used THWM to measure the thermal conductivity of test fluids. Several reasons have been suggested for the discrepancies in these types of measurements, including nanofluid generation, nanofluid stability, and measurement challenges. The details of the transient hot-wire method such as the test cell size, the temperature coefficient of resistance (TCR) and the sampling number are further investigated to improve the accuracy and consistency of the measurements of different researchers. It was observed that smaller test apparatuses were better because they can delay the onset of natural convection. TCR values of a coated platinum wire were measured and statistically analyzed to reduce the uncertainty in thermal conductivity measurements. For validation, ethylene glycol (EG) and water thermal conductivity were measured and analyzed in the temperature range between 280 and 310 K. Furthermore, a detailed statistical analysis was conducted for such measurements, and the results confirmed the minimum number of samples required to achieve the desired resolution and precision of the measurements. It is further proposed that researchers fully report the information related to their measurements to validate the measurements and to avoid future inconsistent nanofluid data.

  19. Passive Sun seeker/tracker and a thermally activated power module

    Science.gov (United States)

    Siebert, C. J.; Morris, F. A.

    1984-01-01

    Development and testing of two mechanisms using a shape memory alloy metal (NITINOL) as the power source are described. The two mechanisms developed are a passive Sun Seeker/Tracker and a generic type power module. These mechanisms use NITINOL wire initially strained in pure torsion which provides the greatest mechanical work capacity upon recovery, as compared to other deformation modes (i.e., tension, helical springs, and bending).

  20. Influence of pre-measurement thermal treatment on OSL of synthetic quartz measured at room temperature

    International Nuclear Information System (INIS)

    Kale, Y.D.; Gandhi, Y.H.

    2008-01-01

    Much effort has been made to study the influence of pre-measurement thermal treatment and ionizing radiation on quartz specimens owing to its use in a large number of applications. Optically stimulated luminescence (OSL) being a structured and sensitive phenomenon promises to correlate the responsible color center and luminescence emission. OSL studies on quartz with such conditions can reveal many significant results. The aim of the present investigation is to understand the effect of annealing temperature on OSL characteristics of synthetic quartz recorded at room temperature. At identical annealing duration and β-dose, the shape of OSL decay curve remains non-exponential; when specimens annealed at lower temperature (∼400 deg. C). The shape of decay curve changes to exponential in nature along with rise in OSL intensity when the specimen was given higher temperature of annealing (>400 deg. C). The effects of such protocol on pattern of OSL sensitivity as well as area under the OSL decay curve are also presented here. The presence of shallow traps, when OSL decay curve was recorded at room temperature seems to be responsible for the changes in OSL pattern. The influence of shallow traps is attributed to non-exponential decay of OSL recorded at room temperature

  1. Dynamic measurement of coal thermal properties and elemental composition of volatile matter during coal pyrolysis

    Directory of Open Access Journals (Sweden)

    Rohan Stanger

    2014-01-01

    Full Text Available A new technique that allows dynamic measurement of thermal properties, expansion and the elemental chemistry of the volatile matter being evolved as coal is pyrolysed is described. The thermal and other properties are measured dynamically as a function of temperature of the coal without the need for equilibration at temperature. In particular, the technique allows for continuous elemental characterisation of tars as they are evolved during pyrolysis and afterwards as a function of boiling point. The technique is demonstrated by measuring the properties of maceral concentrates from a coal. The variation in heats of reaction, thermal conductivity and expansion as a function of maceral composition is described. Combined with the elemental analysis, the results aid in the interpretation of the chemical processes contributing to the physical and thermal behaviour of the coal during pyrolysis. Potential applications in cokemaking studies are discussed.

  2. Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of Inflatable Modules

    Science.gov (United States)

    Mohammed, Anil

    2011-01-01

    This paper focuses on integrating a large hatch penetration into inflatable modules of various constructions. This paper also compares load predictions with test measurements. The strain was measured by utilizing photogrammetric methods and strain gages mounted to select clevises that interface with the structural webbings. Bench testing showed good correlation between strain data collected from an extensometer and photogrammetric measurements, even when the material transitioned from the low load to high load strain region of the curve. The full-scale torus design module showed mixed results as well in the lower load and high strain regions. After thorough analysis of photogrammetric measurements, strain gage measurements, and predicted load, the photogrammetric measurements seem to be off by a factor of two.

  3. Comparison of four-probe thermal and thermoelectric transport measurements of thin films and nanostructures with microfabricated electro-thermal transducers

    Science.gov (United States)

    Kim, Jaehyun; Fleming, Evan; Zhou, Yuanyuan; Shi, Li

    2018-03-01

    Two different four-probe thermal and thermoelectric measurement methods have been reported for measuring the thermal conductivity, Seebeck coefficient, and electrical conductivity of suspended thin films and nanostructures with microfabricated electro-thermal transducers. The thermal contact resistance was extracted from the measured thermoelectric voltage drop at the contacts in the earlier four-probe method based on the assumption of constant thermal and thermoelectric properties along the sample. In comparison, the latter four-probe method can directly obtain the contact thermal resistance together with the intrinsic sample thermal resistance without making this assumption. Here, the measurement theory and data reduction processes of the latter four-probe measurement method are re-examined and improved. The measured thermal conductivity result of this improved method on representative thin film samples are found to agree with those obtained from the earlier four-probe method, which has obtained similar Seebeck coefficient and electrical conductivity as those measured with a different method for a supported thin film. The agreement provides further validation of the latest four-probe thermal transport measurement method of thin films and nanostructures.

  4. Environmental measures for Escuintla No. 3 unit thermal power project

    Energy Technology Data Exchange (ETDEWEB)

    Quisquinay, Carlos; Fabian Rosales, Alejandro [Instituto Nacional de Electrificacion, (Guatemala)

    1996-12-31

    The environmental measures in relation to the project implementation was studied with reference to the Japanese Standards and incorporated in the Implementation Program. This report is prepared however, to review the environmental measures for the project in more detail as to the allowable standards and regulations concerning the measures for the environmental pollution. The authors present the environmental conditions around the Escuintla Power Station in Guatemala; the measures for environmental pollution and evaluation; the measures for prevention of air pollution and diffusion calculations (estimation and assessment of environmental impacts) [Espanol] Las medidas ambientales con relacion a la consolidacion del proyecto, se estudiaron con referencia a los Estandares Japoneses e incorporados en el Programa de Consolidacion. Sin embargo, este reporte ha sido preparado para revisar las medidas ambientales para el proyecto mas detalladamente, con relacion a los estandares y reglamentaciones admisibles concernientes a las medidas de contaminacion ambiental. Los autores presentan las condiciones ambientales en los alrededores de la Central Termoelectrica de Escuintla de Guatemala; las medidas para la prevencion de la contaminacion del aire y los calculos de difusion (estimacion y evaluacion del impacto ambiental)

  5. Environmental measures for Escuintla No. 3 unit thermal power project

    Energy Technology Data Exchange (ETDEWEB)

    Quisquinay, Carlos; Fabian Rosales, Alejandro [Instituto Nacional de Electrificacion, (Guatemala)

    1997-12-31

    The environmental measures in relation to the project implementation was studied with reference to the Japanese Standards and incorporated in the Implementation Program. This report is prepared however, to review the environmental measures for the project in more detail as to the allowable standards and regulations concerning the measures for the environmental pollution. The authors present the environmental conditions around the Escuintla Power Station in Guatemala; the measures for environmental pollution and evaluation; the measures for prevention of air pollution and diffusion calculations (estimation and assessment of environmental impacts) [Espanol] Las medidas ambientales con relacion a la consolidacion del proyecto, se estudiaron con referencia a los Estandares Japoneses e incorporados en el Programa de Consolidacion. Sin embargo, este reporte ha sido preparado para revisar las medidas ambientales para el proyecto mas detalladamente, con relacion a los estandares y reglamentaciones admisibles concernientes a las medidas de contaminacion ambiental. Los autores presentan las condiciones ambientales en los alrededores de la Central Termoelectrica de Escuintla de Guatemala; las medidas para la prevencion de la contaminacion del aire y los calculos de difusion (estimacion y evaluacion del impacto ambiental)

  6. Calorimeter probes for measuring high thermal flux. [in arc jets

    Science.gov (United States)

    Russell, L. D.

    1979-01-01

    Expendable, slug-type calorimeter probes were developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes were constructed with thin tungsten caps mounted on Teflon bodies. The temperature of the back surface of the tungsten cap is measured, and its time rate of change gives the steady-state absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. Design, construction, test, and performance data are presented.

  7. Interpretation of Simultaneous Mechanical-Electrical-Thermal Failure in a Lithium-Ion Battery Module: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Santhanagopalan, Shriram; Stock, Mark J.; Brunhart-Lupo, Nicholas; Gruchalla, Kenny

    2016-12-01

    Lithium-ion batteries are currently the state-of- the-art power sources for electric vehicles, and their safety behavior when subjected to abuse, such as a mechanical impact, is of critical concern. A coupled mechanical-electrical-thermal model for simulating the behavior of a lithium-ion battery under a mechanical crush has been developed. We present a series of production-quality visualizations to illustrate the complex mechanical and electrical interactions in this model.

  8. Thermal management of closed computer modules utilizing high density circuitry. [in Airborne Information Management System

    Science.gov (United States)

    Hoadley, A. W.; Porter, A. J.

    1990-01-01

    This paper presents data on a preliminary analysis of the thermal dynamic characteristics of the Airborne Information Management System (AIMS), which is a continuing design project at NASA Dryden. The analysis established the methods which will be applied to the actual AIMS boards as they become available. The paper also describes the AIMS liquid cooling system design and presents a thermodynamic computer model of the AIMS cooling system, together with an experimental validation of this model.

  9. Evaluation of long term performance measurements of PV modules with different technologies

    OpenAIRE

    Degner, T.; Ries, M.

    2004-01-01

    PV modules of six different technologies (m-Si, mc-Si, EFG, CIS, CdTe, a-Si) have been monitored concerning the performance under external conditions for a period of more than 2 years. In addition to the standard solar radiation measurements with pyranometer solar sensors with corresponding cell technology have been used to supplement the measurements. This allows in principle to consider spectral effects. The solar radiation measured with the sensor and the pyranometer is analysed on monthly...

  10. Measuring Thermal Conductivity of a Small Insulation Sample

    Science.gov (United States)

    Miller, Robert A.; Kuczmarski, Maria A.

    2009-01-01

    A multiple-throat venturi system has been invented for measuring laminar flow of air or other gas at low speed (1 to 30 cm/s) in a duct while preserving the laminar nature of the flow and keeping the velocity profile across the duct as nearly flat as possible. While means for measuring flows at higher speeds are well established, heretofore, there have been no reliable means for making consistent, accurate measurements in this speed range. In the original application for which this system was invented, the duct leads into the test section of a low-speed wind tunnel wherein uniform, low-speed, laminar flow is required for scientific experiments. The system could also be used to monitor a slow flow of gas in an industrial process like chemical vapor deposition. In the original application, the multiple- throat venturi system is mounted at the inlet end of the duct having a rectangular cross section of 19 by 14 cm, just upstream of an assembly of inlet screens and flow straighteners that help to suppress undesired flow fluctuations (see Figure 1). The basic venturi measurement principle is well established: One measures the difference in pressure between (1) a point just outside the inlet, where the pressure is highest and the kinetic energy lowest; and (2) the narrowest part (the throat) of the venturi passage, where the kinetic energy is highest and the pressure is lowest. Then by use of Bernoulli s equation for the relationship between pressure and kinetic energy, the volumetric flow speed in the duct can be calculated from the pressure difference and the inlet and throat widths. The design of this system represents a compromise among length, pressure recovery, uniformity of flow, and complexity of assembly. Traditionally, venturis are used to measure faster flows in narrower cross sections, with longer upstream and downstream passages to maintain accuracy. The dimensions of the passages of the present venturi system are sized to provide a readily measurable

  11. The Analysis Of Accuracy Of Selected Methods Of Measuring The Thermal Resistance Of IGBTs

    Directory of Open Access Journals (Sweden)

    Górecki Krzysztof

    2015-09-01

    Full Text Available In the paper selected methods of measuring the thermal resistance of an IGBT (Insulated Gate Bipolar Transistor are presented and the accuracy of these methods is analysed. The analysis of the measurement error is performed and operating conditions of the considered device, at which each measurement method assures the least measuring error, are pointed out. Theoretical considerations are illustrated with some results of measurements and calculations.

  12. Design and calibration of a test facility for MLI thermal performance measurements below 80K

    International Nuclear Information System (INIS)

    Boroski, W.; Kunzelman, R.; Ruschman, M.; Schoo, C.

    1992-04-01

    The design geometry of the SSC dipole cryostat includes active thermal radiation shields operating at 80K and 20K respectively. Extensive measurements conducted in a Heat Leak Test Facility (HLTF) have been used to evaluate the thermal performance of candidate multilayer insulation (MLI) systems for the 80K thermal shield, with the present system design based upon those measurement results. With the 80K MLI geometry established, efforts have focused on measuring the performance of MLI systems near 20K. A redesign of the HLTF has produced a measurement facility capable of conducting measurements with the warm boundary fixed at 80K and the cold boundary variable from 10K to 50K. Removing the 80K shield permits measurements with a warm boundary at 300K. The 80K boundary consists of a copper shield thermally anchored to a liquid nitrogen reservoir. The cold boundary consists of a copper anchor plate whose temperature is varied through boil-off gas from a 500 liter helium supply dewar. A transfer line heat exchanger supplies the boil-off gas to the anchor plate at a constant and controlled rate. The gas, which serves as cooling gas, is routed through a copper cooling tube soldered into the anchor plate. Varying the cooling gas flow rate varies the amount of refrigeration supplied to the anchor plate, thereby determining the plate temperature. A resistance heater installed on the anchor plate is regulated by a cryogenic temperature controller to provide final temperature control. Heat leak values are measured using a heatmeter which senses heat flow as a temperature gradient across a fixed thermal impedance. Since the thermal conductivity of the thermal impedance changes with temperature, the heatmeter is calibrated at key cold boundary temperatures. Thus, the system is capable of obtaining measurement data under a variety of system conditions. 7 refs

  13. Investigation of the thermal and optical performance of a spatial light modulator with high average power picosecond laser exposure for materials processing applications

    Science.gov (United States)

    Zhu, G.; Whitehead, D.; Perrie, W.; Allegre, O. J.; Olle, V.; Li, Q.; Tang, Y.; Dawson, K.; Jin, Y.; Edwardson, S. P.; Li, L.; Dearden, G.

    2018-03-01

    Spatial light modulators (SLMs) addressed with computer generated holograms (CGHs) can create structured light fields on demand when an incident laser beam is diffracted by a phase CGH. The power handling limitations of these devices based on a liquid crystal layer has always been of some concern. With careful engineering of chip thermal management, we report the detailed optical phase and temperature response of a liquid cooled SLM exposed to picosecond laser powers up to 〈P〉  =  220 W at 1064 nm. This information is critical for determining device performance at high laser powers. SLM chip temperature rose linearly with incident laser exposure, increasing by only 5 °C at 〈P〉  =  220 W incident power, measured with a thermal imaging camera. Thermal response time with continuous exposure was 1-2 s. The optical phase response with incident power approaches 2π radians with average power up to 〈P〉  =  130 W, hence the operational limit, while above this power, liquid crystal thickness variations limit phase response to just over π radians. Modelling of the thermal and phase response with exposure is also presented, supporting experimental observations well. These remarkable performance characteristics show that liquid crystal based SLM technology is highly robust when efficiently cooled. High speed, multi-beam plasmonic surface micro-structuring at a rate R  =  8 cm2 s-1 is achieved on polished metal surfaces at 〈P〉  =  25 W exposure while diffractive, multi-beam surface ablation with average power 〈P〉  =100 W on stainless steel is demonstrated with ablation rate of ~4 mm3 min-1. However, above 130 W, first order diffraction efficiency drops significantly in accord with the observed operational limit. Continuous exposure for a period of 45 min at a laser power of 〈P〉  =  160 W did not result in any detectable drop in diffraction efficiency, confirmed afterwards by the efficient

  14. Experimental studies for improvement of thermal effects in a high-power fiber-coupled diode laser module operating at 808 nm

    Science.gov (United States)

    El-Sherif, Ashraf F.; Hussein, Khalid; Hassan, Mahmoud F.; Talat, Mahmoud M.

    2012-03-01

    High power diode laser module operating at 808 nm is required for different applications, such as developing an efficient high power Nd3+-doped solid state laser and Tm3+ -doped silica fiber laser, industrial, medical and military applications. Optical and thermal images characterization for a fiber-coupled high power diode laser module is presented experimentally for 6.6 Watt output optical power .An external temperature controller system was designed, which stabilizes the central wavelength at 808 nm at 25°C over a wide range of diode laser driving current from 1A to 6 A. without this cooling system, the wavelength changes by 0.35nm/°C for temperature changes from 20°C to 40°C at the same range of the driving current. In this paper we have present a methodology for temperature reduction of a 808 nm high power diode laser module, based on dynamically thermal control, which is known as dynamic thermal management. Stabilization of the output wavelength has been done by using proportional speed control (PSC) of a CPU cooling fan with certain scheme of straight fins heat sink. Two electronic circuits based on pulse width modulation (PWM) in microcontroller and comparators IC have been used. This technique can be considered as an effective mechanism for reducing temperature and power dissipation to make stabilization of the diode laser output wavelength by preventing heat accumulation from the thermo electric cooling (TEC) inside the diode laser module confirmed by thermal images.

  15. Measurements of ocean wave spectra and modulation transfer function with the airborne two-frequency scatterometer

    Science.gov (United States)

    Weissman, D. E.; Johnson, J. W.

    1986-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  16. Measurements of ocean wave spectra and modulation transfer function with the airborne two frequency scatterometer

    Science.gov (United States)

    Weissman, D. E.; Johnson, J. W.

    1984-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  17. A method to measure the thermal-physical parameter of gas hydrate in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Diao, S.B.; Ye, Y.G.; Yue, Y.J.; Zhang, J.; Chen, Q.; Hu, G.W. [Qingdao Inst. of Marine Geology, Qingdao (China)

    2008-07-01

    It is important to explore and make good use of gas hydrates through the examination of the thermal-physical parameters of sediment. This paper presented a new type of simulation experiment using a device that was designed based on the theories of time domain reflection and transient hot wire method. A series of investigations were performed using this new device. The paper described the experiment, with reference to the experiment device and materials and method. It also presented the results of thermal physical properties; result of the thermal conductivity of water, dry sand and wet sand; and results of wet sand under various pressures. The time domain reflection (TDR) method was utilized to monitor the saturation of the hydrates. Both parallel hot-wire method and cross hot-wire method were utilized to measure the thermal conductivity of the gas hydrate in porous media. A TDR sensor which was equipped with both cross hot-wire probe and parallel hot-wire probe was developed in order to measure the cell temperature with these two methods at one time. It was concluded that the TDR probe could be taken as an online measurement skill in investigating the hydrate thermal physical property in porous media. The TDR sensor could monitor the hydrate formation process and the parallel hot-wire method and cross hot-wire method could effectively measure the thermal physical properties of the hydrates in porous media. 10 refs., 7 figs.

  18. Estimation of the thermal diffusion coefficient in fusion plasmas taking frequency measurement uncertainties into account

    International Nuclear Information System (INIS)

    Van Berkel, M; Hogeweij, G M D; Van den Brand, H; De Baar, M R; Zwart, H J; Vandersteen, G

    2014-01-01

    In this paper, the estimation of the thermal diffusivity from perturbative experiments in fusion plasmas is discussed. The measurements used to estimate the thermal diffusivity suffer from stochastic noise. Accurate estimation of the thermal diffusivity should take this into account. It will be shown that formulas found in the literature often result in a thermal diffusivity that has a bias (a difference between the estimated value and the actual value that remains even if more measurements are added) or have an unnecessarily large uncertainty. This will be shown by modeling a plasma using only diffusion as heat transport mechanism and measurement noise based on ASDEX Upgrade measurements. The Fourier coefficients of a temperature perturbation will exhibit noise from the circular complex normal distribution (CCND). Based on Fourier coefficients distributed according to a CCND, it is shown that the resulting probability density function of the thermal diffusivity is an inverse non-central chi-squared distribution. The thermal diffusivity that is found by sampling this distribution will always be biased, and averaging of multiple estimated diffusivities will not necessarily improve the estimation. Confidence bounds are constructed to illustrate the uncertainty in the diffusivity using several formulas that are equivalent in the noiseless case. Finally, a different method of averaging, that reduces the uncertainty significantly, is suggested. The methodology is also extended to the case where damping is included, and it is explained how to include the cylindrical geometry. (paper)

  19. Direct measurement of thermal conductivity in solid iron at planetary core conditions.

    Science.gov (United States)

    Konôpková, Zuzana; McWilliams, R Stewart; Gómez-Pérez, Natalia; Goncharov, Alexander F

    2016-06-02

    The conduction of heat through minerals and melts at extreme pressures and temperatures is of central importance to the evolution and dynamics of planets. In the cooling Earth's core, the thermal conductivity of iron alloys defines the adiabatic heat flux and therefore the thermal and compositional energy available to support the production of Earth's magnetic field via dynamo action. Attempts to describe thermal transport in Earth's core have been problematic, with predictions of high thermal conductivity at odds with traditional geophysical models and direct evidence for a primordial magnetic field in the rock record. Measurements of core heat transport are needed to resolve this difference. Here we present direct measurements of the thermal conductivity of solid iron at pressure and temperature conditions relevant to the cores of Mercury-sized to Earth-sized planets, using a dynamically laser-heated diamond-anvil cell. Our measurements place the thermal conductivity of Earth's core near the low end of previous estimates, at 18-44 watts per metre per kelvin. The result is in agreement with palaeomagnetic measurements indicating that Earth's geodynamo has persisted since the beginning of Earth's history, and allows for a solid inner core as old as the dynamo.

  20. In situ generated gas bubble-assisted modulation of the morphologies, photocatalytic, and magnetic properties of ferric oxide nanostructures synthesized by thermal decomposition of iron nitrate

    International Nuclear Information System (INIS)

    Tong Guoxiu; Guan Jianguo; Xiao Zhidong; Huang Xing; Guan Yao

    2010-01-01

    Ferric oxide (Fe 2 O 3 ) complex nanoarchitectures with high BET specific surface area, superior photocatalytic activity and modulated magnetic properties are facilely synthesized via controlled thermal decomposition of iron(III) nitrate nonahydrate. The products are characterized by X-ray diffraction, Fourier-transforming infrared spectra, field-emission scanning electron microscope, field-emission high-resolution transmission electron microscope, and nitrogen physisorption and micrometrics analyzer. The corresponding photocatalytic activity and static magnetic properties are also evaluated by measuring the photocatalytic degradation of Rhodamine B aqueous solution under visible light illumination and vibrating sample magnetometer, respectively. Simply tuning the decomposition temperature can conveniently modulate the adsorbing/desorbing behaviors of the in situ generated gases on the nucleus surfaces, and consequently the crystalline structures and morphologies of the Fe 2 O 3 complex nanoarchitectures. The as-prepared Fe 2 O 3 complex nanoarchitectures show strong crystal structure and/or morphology-dependent photocatalytic and magnetic performances. The Fe 2 O 3 complex nanoarchitectures with high specific surface area and favorable crystallization are found to be beneficial for improving the photocatalytic activity. This work not only reports a convenient and low-cost decomposition procedure and a novel formation mechanism of complex nanoarchitectures but also provides an efficient route to enhance catalytic and magnetic properties of Fe 2 O 3 .

  1. Thermal hydraulics-II. 2. Benchmarking of the TRIO Two-Phase-Flow Module

    International Nuclear Information System (INIS)

    Helton, Donald; Kumbaro, Anela; Hassan, Yassin

    2001-01-01

    The Commissariat a l'Energie Atomique (CEA) is currently developing a two-phase-flow module for the Trio-U CFD computer program. Work in the area of advanced numerical technique application to two-phase flow is being carried out by the SYSCO division at the CEA Saclay center. Recently, this division implemented several advanced numerical solvers, including approximate Riemann solvers and flux vector splitting schemes. As a test of these new advances, several benchmark tests were executed. This paper describes the pertinent results of this study. The first benchmark problem was the Ransom faucet problem. This problem consists of a vertical column of water acting under the gravity force. The appeal of this problem is that it tests the program's handling of the body force term and it has an analytical solution. The Trio results [based on a two-fluid, two-dimensional (2-D) simulation] for this problem were very encouraging. The two-phase-flow module was able to reproduce the analytical velocity and void fraction profiles. A reasonable amount of numerical diffusion was observed, and the numerical solution converged to the analytical solution as the grid size was refined, as shown in Fig. 1. A second series of benchmark problems is concerned with the employment of a drag force term. In a first approach, we test the capability of the code to take account of this source term, using a flux scheme solution technique. For this test, a rectangular duct was utilized. As shown in Fig. 2, mesh refinement results in an approach to the analytical solution. Next, a convergent/divergent nozzle problem is proposed. The nozzle is characterized by a brief contraction section and a long expansion section. A two-phase, 2-D, non-condensing model is used in conjunction with the Rieman solver. Figure 3 shows a comparison of the pressure profile for the experimental case and for the values calculated by the TRIO U two-phase-flow module. Trio was able to handle the drag force term and

  2. Thermal diffusion through amalgam and cement base: comparison of in vitro and in vivo measurements.

    Science.gov (United States)

    Tibbetts, V R; Schnell, R J; Swartz, M L; Phillips, R W

    1976-01-01

    Thermal diffusion was measured in vitro and in vivo through amalgam and amalgam underlaid with bases of zinc phosphate, zinc oxide-eugenol, and calcium hydroxide cements. Although the magnitudes differed, there generally was good agreement between in vitro and in vivo data with respect to the relative rates of thermal diffusivity through amalgam restorations underlaid with bases of each of the three materials. In all tests, both in vitro and in vivo, the zinc oxide-eugenol base proved to be the best thermal insulator. Calcium hydroxide was the next best thermal barrier and was followed by zinc phosphate cement. In vitro tests indicated dentin to be a better thermal insulator than zinc phosphate cement but inferior to the zinc oxide-eugenol and calcium hydroxide base materials used here. Although a method has been presented here for the in vivo assessment of the efficacy of thermal insulating bases and a number of in vivo experiments were conducted, much research remains to be done in this area. Additional investigation is needed to better define the parameters of thermal change beneath various types of restoratives and also to establish more exactly the role of base thickness in providing thermal protection beneath clinical metallic restorations.

  3. Measurement and Estimation of Effective Thermal Conductivity for Sodium based Nanofluid using 3-Omega Method

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sun Ryung; Park, Hyun Sun [POSTECH, Pohang (Korea, Republic of); Kim, Moo Hwan [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The sodium-cooled fast reactor (SFR) is one of generation IV type reactors and has been extensively researched since 1950s. A strong advantage of the SFR is its liquid sodium coolant which is well-known for its superior thermal properties. However, in terms of possible pipe leakage or rupture, a liquid sodium coolant possesses a critical issue due to its high chemical reactivity which leads to fire or explosion. Due to its safety concerns, dispersion of nanoparticles in liquid sodium has been proposed to reduce the chemical reactivity of sodium. In case of sodium based titanium nanofluid (NaTiNF), the chemical reactivity suppression effect when interacting with water has been proved both experimentally and theoretically [1,2]. Suppression of chemical reactivity is critical without much loss of high heat transfer characteristic of sodium. As there is no research conducted for applying 3-omega sensor in liquid metal as well as high temperature liquid, the sensor development is performed for using in NaTiNF as well as effective thermal conductivity model validation. Based on the acquired effective thermal conductivity of NaTiNF, existing effective thermal conductivity models are evaluated. Thermal conductivity measurement is performed for liquid sodium based titanium nanofluid (NaTiNF) through 3-Omega method. The experiment is conducted at three temperature points of 120, 150, and 180 .deg. C for both pure liquid sodium and NaTiNF. By using 3- omega sensor, thermal conductivity measurement of liquid metal can be more conveniently conducted in labscale. Also, its possibility to measure the thermal conductivity of high temperature liquid metal with metallic nanoparticles being dispersed is shown. Unlike other water or oil-based nanofluids, NaTiNF exhibits reduction of thermal conductivity compare with liquid sodium. Various nanofluid models are plotted, and it is concluded that the MSBM which considers interfacial resistance and Brownian motion can be used in predicting

  4. Measurement and Estimation of Effective Thermal Conductivity for Sodium based Nanofluid using 3-Omega Method

    International Nuclear Information System (INIS)

    Oh, Sun Ryung; Park, Hyun Sun; Kim, Moo Hwan

    2016-01-01

    The sodium-cooled fast reactor (SFR) is one of generation IV type reactors and has been extensively researched since 1950s. A strong advantage of the SFR is its liquid sodium coolant which is well-known for its superior thermal properties. However, in terms of possible pipe leakage or rupture, a liquid sodium coolant possesses a critical issue due to its high chemical reactivity which leads to fire or explosion. Due to its safety concerns, dispersion of nanoparticles in liquid sodium has been proposed to reduce the chemical reactivity of sodium. In case of sodium based titanium nanofluid (NaTiNF), the chemical reactivity suppression effect when interacting with water has been proved both experimentally and theoretically [1,2]. Suppression of chemical reactivity is critical without much loss of high heat transfer characteristic of sodium. As there is no research conducted for applying 3-omega sensor in liquid metal as well as high temperature liquid, the sensor development is performed for using in NaTiNF as well as effective thermal conductivity model validation. Based on the acquired effective thermal conductivity of NaTiNF, existing effective thermal conductivity models are evaluated. Thermal conductivity measurement is performed for liquid sodium based titanium nanofluid (NaTiNF) through 3-Omega method. The experiment is conducted at three temperature points of 120, 150, and 180 .deg. C for both pure liquid sodium and NaTiNF. By using 3- omega sensor, thermal conductivity measurement of liquid metal can be more conveniently conducted in labscale. Also, its possibility to measure the thermal conductivity of high temperature liquid metal with metallic nanoparticles being dispersed is shown. Unlike other water or oil-based nanofluids, NaTiNF exhibits reduction of thermal conductivity compare with liquid sodium. Various nanofluid models are plotted, and it is concluded that the MSBM which considers interfacial resistance and Brownian motion can be used in predicting

  5. Thermal conductivity measurement of HTS tapes and stacks for current lead applications

    International Nuclear Information System (INIS)

    Schwarz, Michael; Weiss, Klaus-Peter; Heller, Reinhard; Fietz, Walter H.

    2009-01-01

    The use of high-temperature-superconductors (HTS) within current leads offers a high potential to save cooling-power. The principle of HTS current leads is well established, e.g. for particle accelerators (LHC-CERN) but also on the commercial sector, which offer HTS current leads ready for use in small scale magnets and magnets systems. Future fusion machines currently under construction like ITER, W7-X or JT-60SA also will use HTS current leads. At the moment the standard material for HTS current leads is a Bi 2 Sr 2 Ca 2 Cu 3 O x (BSCCO)-AgAu composite tape. The common way to receive high current capacity current leads is to form stacks by sintering or soldering these tapes together. The solder changes the thermal conductivity of the stacks compared to the single tape in the temperature range from 4 K to 60 K. To estimate the heat flux from the warm environment to the cold application the measurement of the thermal conductivity of the soldered stack is mandatory. Therefore the thermal conductivity of stacks with different number of tapes is investigated. To measure the thermal conduction in the current flow direction, the axial heat flow method is used. Combining these results with FEM simulations gives the possibility to estimate the thermal conductivity normal to the flat tape plane. The resulting anisotropic thermal conductivity can be used to model the behaviour of the HTS tape under thermal disturbances more accurately.

  6. The design of high-temperature thermal conductivity measurements apparatus for thin sample size

    Directory of Open Access Journals (Sweden)

    Hadi Syamsul

    2017-01-01

    Full Text Available This study presents the designing, constructing and validating processes of thermal conductivity apparatus using steady-state heat-transfer techniques with the capability of testing a material at high temperatures. This design is an improvement from ASTM D5470 standard where meter-bars with the equal cross-sectional area were used to extrapolate surface temperature and measure heat transfer across a sample. There were two meter-bars in apparatus where each was placed three thermocouples. This Apparatus using a heater with a power of 1,000 watts, and cooling water to stable condition. The pressure applied was 3.4 MPa at the cross-sectional area of 113.09 mm2 meter-bar and thermal grease to minimized interfacial thermal contact resistance. To determine the performance, the validating process proceeded by comparing the results with thermal conductivity obtained by THB 500 made by LINSEIS. The tests showed the thermal conductivity of the stainless steel and bronze are 15.28 Wm-1K-1 and 38.01 Wm-1K-1 with a difference of test apparatus THB 500 are −2.55% and 2.49%. Furthermore, this apparatus has the capability to measure the thermal conductivity of the material to a temperature of 400°C where the results for the thermal conductivity of stainless steel is 19.21 Wm-1K-1 and the difference was 7.93%.

  7. Measurement of thermal neutron spectra using LINAC in Japan Atomic Energy Research Institute (JAERI)

    International Nuclear Information System (INIS)

    Akino, Fujiyoshi

    1982-01-01

    The exact grasp of thermal neutron spectra in a core region is very important for obtaining accurate thermal neutron group constants in the calculation for the nuclear design of a reactor core. For the accurate grasp of thermal neutron spectra, the capability of thermal neutron spectra to describe the moderator cross-sections for thermal neutron scattering is a key factor. Accordingly, 0 deg angular thermal neutron spectra were measured by the time of flight (TOF) method using the JAERI LINAC as a pulsed neutron source, for light water system added with Cd and In, high temperature graphite system added with boron, and light water-natural uranium heterogeneous multiplication system among the reactor moderators of light water or graphite systems. First, the equations to give the time of flight and neutron flux by TOF method were analyzed, and several corrections were investigated, such as those for detector efficiency, background, the transmission coefficient of air and the Al window of a flight tube, mean emission time of neutrons, and the distortion effect of re-entrant hole on thermal neutron spectra. Then, the experimental system, results and calculation were reported for the experiments on the above three moderator systems. Finally, the measurement of fast neutron spectra in natural uranium system and that of the efficiency of a 6 Li glass scintillator detector are described. (Wakatsuki, Y.)

  8. A novel test method for measuring the thermal properties of clothing ensembles under dynamic conditions

    International Nuclear Information System (INIS)

    Wan, X; Fan, J

    2008-01-01

    The dynamic thermal properties of clothing ensembles are important to thermal transient comfort, but have so far not been properly quantified. In this paper, a novel test procedure and new index based on measurements on the sweating fabric manikin-Walter are proposed to quantify and measure the dynamic thermal properties of clothing ensembles. Experiments showed that the new index is correlated to the changing rate of the body temperature of the wearer, which is an important indicator of thermal transient comfort. Clothing ensembles having higher values of the index means the wearer will have a faster changing rate of body temperature and shorter duration before approaching a dangerous thermo-physiological state, when he changes from 'resting' to 'exercising' mode. Clothing should therefore be designed to reduce the value of the index

  9. A new method for measuring the thermal regulatory properties of phase change material (PCM) fabrics

    International Nuclear Information System (INIS)

    Wan, X; Fan, J

    2009-01-01

    Several methods already exist for the measurement of the thermal regulatory properties of fabrics containing phase change materials (PCMs). However, they do not adequately simulate the actual use condition; consequently the measurements may not have relevance to the performance of PCM fabrics in actual use. Here we report on the development of a new method, which better simulates the real use situation. In this method, a hot plate, simulating the human body, generates a constant amount of heat depending on the type of human activity to be simulated. The hot plate covered by the PCM fabric is then exposed to a thermal transient simulating a wearer moving from one thermal environment to another; the changes of surface temperature and heat loss of the hot plate are then recorded and used to characterize the thermal regulatory properties of the PCM fabrics

  10. A heat source probe for measuring thermal conductivity in waste rock dumps

    International Nuclear Information System (INIS)

    Blackford, M.G.; Harries, J.R.

    1985-10-01

    The development and use of a heat source probe to measure the thermal conductivity of the material in a waste rock dump is described. The probe releases heat at a constant rate into the surrounding material and the resulting temperature rise is inversely related to the thermal conductivity. The probe was designed for use in holes in the dump which are lined with 50 mm i.d. polyethylene liners. The poor thermal contact between the probe and the liner and the unknown conductivity of the backfill material around the liner necessitated long heating and cooling times (>10 hours) to ensure that the thermal conductivity of the dump material was being measured. Temperature data acquired in the field were analysed by comparing them with temperatures calculated using a two-dimensional cylindrical model of the probe and surrounding material, and the heat transfer code HEATRAN

  11. THERMAL LENSING MEASUREMENTS IN THE ANISOTROPIC LASER CRYSTALS UNDER DIODE PUMPING

    Directory of Open Access Journals (Sweden)

    P. A. Loiko

    2012-01-01

    Full Text Available An experimental setup was developed for thermal lensing measurements in the anisotropic diode-pumped laser crystals. The studied crystal is placed into the stable two-mirror laser cavity operating at the fundamental transversal mode. The output beam radius is measured with respect to the pump intensity for different meridional planes (all these planes contain the light propagation direction. These dependencies are fitted using the ABCD matrix method in order to obtain the sensitivity factors showing the change of the optical power of thermal lens due to variation of the pump intensity. The difference of the sensitivity factors for two mutually orthogonal principal meridional planes describes the thermal lens astigmatism degree. By means of this approach, thermal lensing was characterized in the diode-pumped monoclinic Np-cut Nd:KGd(WO42 laser crystal at the wavelength of 1.067 μm for light polarization E || Nm.

  12. Thermal indoor environment and energy consumption in a plus-energy house: cooling season measurements

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Olesen, Bjarne W.

    2015-01-01

    indoor environment. For the energy consumption of the HVAC system, air-to-brine heat pump, mixing station and controller of the radiant floor, and the air handling unit were considered. The measurements were analyzed based on the achieved indoor environment category (according to EN 15251...... the floor cooling system) and increasing the ventilation rate provided a better thermal indoor environment but with increased energy consumption. The thermal indoor environment and energy performance of the house can be improved with decreased glazing area, increased thermal mass, installation of solar...

  13. Relative measurement of the fluxes of thermal, resonant and rapid neutrons in reactor G1

    International Nuclear Information System (INIS)

    Carle, R.; Mazancourt, T. de

    1957-01-01

    We sought to determine the behavior of the thermal, resonant and rapid neutron fluxes in the multiplier-reflector transition region, in the two principal directions of the system. We have also measured the variation of these different fluxes in the body of the multiplier medium in a canal filled with graphite and in an empty canal. The results are given in the form of curves representing: - the variation of the ratio of the thermal flux to the rapid flux in axial and radial transitions - the behavior of the thermal and resonant fluxes and the variation of their ratio in the same regions. (author) [fr

  14. Pressure Wave Measurements from Thermal Cook-Off of an HMX Based High Explosive PBX 9501

    International Nuclear Information System (INIS)

    Garcia, F.; Forbes, J.W.; Tarver, C.M.; Urtiew, P.A.; Greenwood, D.W.; Vandersall, K.S.

    2001-01-01

    A better understanding of thermal cook-off is important for safe handling and storing explosive devices. A number of safety issues exist about what occurs when a cased explosive thermally cooks off. For example, violence of the events as a function of confinement are important for predictions of collateral damage. This paper demonstrates how adjacent materials can be gauged to measure the resulting pressure wave and how this wave propagates in this adjacent material. The output pulse from the thermal cook-off explosive containing fixture is of obvious interest for assessing many scenarios

  15. Low-temperature thermal expansion measurements in PrV2Al20

    International Nuclear Information System (INIS)

    Magata, A.; Matsumoto, Y.; Tsujimoto, M.; Tomita, T.; Sakai, A.; Nakatsuji, S.; Kiichler, R.

    2016-01-01

    We have measured thermal expansion of PrV 2 Al 20 and LaV 2 Al 20 from room temperature down to 2 K, using a capacitance dilatometer. Linear thermal expansion ΔL/L along [111] direction decreases monotonically on cooling in both materials. The extracted 4ƒ electrons contribution of the linear thermal expansion coefficient a clearly shows a broad peak at ∼ 30 K which may correspond to the crystal electric field excited state at 40 K suggested in the previous specific heat study. (paper)

  16. Measurements of scattering, transmittance/reflectance, IR-transmittance and thermal conductivity of small aerogel samples

    DEFF Research Database (Denmark)

    Duer, Karsten; Svendsen, Sv Aa Højgaard

    1997-01-01

    By providing at the same time thermal insulation and transparency the silica aerogel is a very attractive material for the purpose of improving the thermal performance of windows. Nevertheless a lot of problems have to be solved on the way from concept to the developed product. The B1 Aerogels...... project deals with some of these problems.This report summarizes the work that has been carried out on the subject of characterizing the optical and thermal performance of different types of aerogels and aerogel-like materials for the purpose of using aerogel in clear glazings.All measurements presented...

  17. Degradation and performance evaluation of PV module in desert climate conditions with estimate uncertainty in measuring

    Directory of Open Access Journals (Sweden)

    Fezzani Amor

    2017-01-01

    Full Text Available The performance of photovoltaic (PV module is affected by outdoor conditions. Outdoor testing consists installing a module, and collecting electrical performance data and climatic data over a certain period of time. It can also include the study of long-term performance under real work conditions. Tests are operated in URAER located in desert region of Ghardaïa (Algeria characterized by high irradiation and temperature levels. The degradation of PV module with temperature and time exposure to sunlight contributes significantly to the final output from the module, as the output reduces each year. This paper presents a comparative study of different methods to evaluate the degradation of PV module after a long term exposure of more than 12 years in desert region and calculates uncertainties in measuring. Firstly, this evaluation uses three methods: Visual inspection, data given by Solmetric PVA-600 Analyzer translated at Standard Test Condition (STC and based on the investigation results of the translation equations as ICE 60891. Secondly, the degradation rates calculated for all methods. Finally, a comparison between a degradation rates given by Solmetric PVA-600 analyzer, calculated by simulation model and calculated by two methods (ICE 60891 procedures 1, 2. We achieved a detailed uncertainty study in order to improve the procedure and measurement instrument.

  18. Advanced intensity-modulation continuous-wave lidar techniques for ASCENDS CO2 column measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. W.; Obland, Michael D.; Meadows, Byron

    2015-10-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  19. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for ASCENDS O2 Column Measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Meadows, Byron

    2015-01-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  20. Oscillatory instability of a self-rewetting film driven by thermal modulation

    Science.gov (United States)

    Batson, William; Agnon, Yehuda; Oron, Alex

    2016-11-01

    Here we consider the self-rewetting fluids (SRWFs) that exhibit a well-defined minimum surface tension with respect to temperature, in contrast to those where surface tension decreases linearly. Utilization of SRWFs has grown significantly in the past decade, due to observations that heat transfer is enhanced in applications such as film boiling and pulsating heat pipes. With similar applications in mind, we investigate the dynamics of a thin SRWF film which is subjected to a temperature modulation in the bounding gas. A model is developed within the framework of the long-wave approximation, and a time-averaged thermocapillary driving force for destabilization is uncovered for SRWFs that results from the nonlinear surface tension. Linear analysis of the nonlinear PDE for the film thickness is used to determine the critical conditions at which this driving force destabilizes the film, and, numerical integration of this evolution equation reveals that linearly unstable perturbations saturate to regular periodic solutions (when the modulational frequency is set properly). Properties of these flows such as bifurcation and long-domain flows, where multiple unstable linear modes interact, will also be discussed.

  1. Thermal insulation

    International Nuclear Information System (INIS)

    Aspden, G.J.; Howard, R.S.

    1988-01-01

    The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

  2. Measuring Airflow in Local Exhaust Ventilation Systems. Module 23. Vocational Education Training in Environmental Sciences.

    Science.gov (United States)

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on measuring airflow in local exhaust ventilation systems. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each…

  3. Evaluation of the quasi-isothermal method of modulated DSC for heat capacity measurement

    International Nuclear Information System (INIS)

    Venkata Krishnan, R.; Nagarajan, K.

    2004-01-01

    Heat capacity measurements were carried out on ThO 2 by Modulated Differential Scanning Calorimetry (MDSC) using quasi-isothermal method in the temperature range 323-723 K. The highest accuracy of the heat capacity data obtained by this method was ± 2-3% which is much lower than that reported in the literature. (author)

  4. Thermal expansion measurements on boron carbide and europium sesquioxide by laser interferometry

    International Nuclear Information System (INIS)

    Preston, S.D.

    1980-01-01

    A laser interferometer technique for measuring the absolute linear thermal expansion of small annular specimens is described. Results are presented for unirradiated boron carbide (B 4 C) and europia (Eu 2 O 3 ) up to 1000 0 C. Both compounds are neutron-absorbing materials of potential use in fast-reactor control rods and data on their thermophysical properties, in particular linear thermal expansion, are essential to the control rod designers. (author)

  5. Measurement of the effective thermal cross section of {sup 134}Cs by triple neutron capture reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Shoji; Harada, Hideo; Katoh, Toshio [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works; Hatsukawa, Yuichi; Shinohara, Nobuo; Hata, Kentaro; Kobayashi, Katsutoshi; Motoishi, Shoji; Tanase, Masakazu

    1998-03-01

    The effective thermal cross section ({sigma}{sub eff}) of the {sup 134}Cs(n,{gamma}){sup 135}Cs reaction was measured by the activation method and the {gamma}-ray spectroscopic method in order to obtain fundamental data for research on the transmutation of nuclear wastes. The effective thermal cross section of the reaction {sup 134}Cs(n,{gamma}){sup 135}Cs was found to be 140.6{+-}8.5 barns. (author)

  6. Measurement of thermal conductivity of uranium metal using transient plane source technique

    International Nuclear Information System (INIS)

    Subramanian, G.G.S.; Bapuji, T.; Panneerselvam, G.; Antony, M.P.; Nagarajan, K.

    2012-01-01

    Thermo physical properties of fuel, cladding and structural materials play a significant role in the reactor operation. Thermal conductivity is one of the most important physical properties of the fuel which determines the maximum linear heat rating of the fuel in a reactor. As part of this study, the thermal conductivity of uranium metal was measured using a transient plane source (TPS) by Hot-disc method

  7. Measured Thermal and Fast Neutron Fluence Rates for ATF-1 Holders During ATR Cycle 157D

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Larry Don [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, David Torbet [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 157D which were measured by the Radiation Measurements Laboratory (RML) as requested by the Power Reactor Programs (ATR Experiments) Radiation Measurements Work Order. This report contains measurements of the fluence rates corresponding to the particular elevations relative to the 80-ft. core elevation. The data in this report consist of (1) a table of the ATR power history and distribution, (2) a hard copy listing of all thermal and fast neutron fluence rates, and (3) plots of both the thermal and fast neutron fluence rates. The fluence rates reported are for the average power levels given in the table of power history and distribution.

  8. Online In-Core Thermal Neutron Flux Measurement for the Validation of Computational Methods

    International Nuclear Information System (INIS)

    Mohamad Hairie Rabir; Muhammad Rawi Mohamed Zin; Yahya Ismail

    2016-01-01

    In order to verify and validate the computational methods for neutron flux calculation in RTP calculations, a series of thermal neutron flux measurement has been performed. The Self Powered Neutron Detector (SPND) was used to measure thermal neutron flux to verify the calculated neutron flux distribution in the TRIGA reactor. Measurements results obtained online for different power level of the reactor. The experimental results were compared to the calculations performed with Monte Carlo code MCNP using detailed geometrical model of the reactor. The calculated and measured thermal neutron flux in the core are in very good agreement indicating that the material and geometrical properties of the reactor core are modelled well. In conclusion one can state that our computational model describes very well the neutron flux distribution in the reactor core. Since the computational model properly describes the reactor core it can be used for calculations of reactor core parameters and for optimization of RTP utilization. (author)

  9. Te(R,t) Measurements using Electron Bernstein Wave Thermal Emission on NSTX

    International Nuclear Information System (INIS)

    Diem, S.J.; Taylor, G.; Efthimion, P.C.; LeBlanc, B.P.; Carter, M.; Caughman, J.; Wilgen, J.B.; Harvey, R.W.; Preinhaelter, J.; Urban, J.

    2006-01-01

    The National Spherical Torus Experiment (NSTX) routinely studies overdense plasmas with n e of (1-5) x 10 19 m -3 and total magnetic field of e measurement. A significant upgrade to the previous NSTX EBW emission diagnostic to measure thermal EBW emission via the oblique B-X-O mode conversion process has been completed. The new EBW diagnostic consists of two remotely steerable, quad-ridged horn antennas, each of which is coupled to a dual channel radiometer. Fundamental (8-18 GHz) and second and third harmonic (18-40 GHz) thermal EBW emission and polarization measurements can be obtained simultaneously.

  10. Thermal conductivity measurements of PTFE and Al2O3 ceramic at sub-Kelvin temperatures

    Science.gov (United States)

    Drobizhev, Alexey; Reiten, Jared; Singh, Vivek; Kolomensky, Yury G.

    2017-07-01

    The design of low temperature bolometric detectors for rare event searches necessitates careful selection and characterization of structural materials based on their thermal properties. We measure the thermal conductivities of polytetrafluoroethylene (PTFE) and Al2O3 ceramic (alumina) in the temperature ranges of 0.17-0.43 K and 0.1-1.3 K, respectively. For the former, we observe a quadratic temperature dependence across the entire measured range. For the latter, we see a cubic dependence on temperature above 0.3 K, with a linear contribution below that temperature. This paper presents our measurement techniques, results, and theoretical discussions.

  11. Thermal diffusivity measurements of liquid materials at high temperature with the ''laser flash'' method

    International Nuclear Information System (INIS)

    Otter, Claude; Vandevelde, Jean

    1982-01-01

    Two solutions, one analytical and the other numerical are proposed to solve the thermokinetic problem encountered when measuring the thermal diffusivity of liquid materials at very high temperature (T>3123K). The liquid material is contained in a parallel faced vessel. This liquid is traversed by a short thermal pulse from a relaxed laser. The temperature response of the back face of the measurement cell is analysed. The first model proposed which does not take thermal losses into consideration, is a mathematical model derived from the ''two layer model'' (Larson and Koyama, 1968) extended to ''three layers''. In order to take the possibility of thermal losses to the external environment at high temperature into consideration, a Crank-Nicolson (1947) type numerical model utilizing finite differences is employed. These thermokinetic studies were performed in order to interpret temperature response curves obtained from the back face of a tungsten-liquid UO 2 -tungsten thermal wall, the purpose of the measurements made being to determine the thermal properties of liquid uranium oxide [fr

  12. Thermal conductivity measurements in porous mixtures of methane hydrate and quartz sand

    Science.gov (United States)

    Waite, W.F.; deMartin, B.J.; Kirby, S.H.; Pinkston, J.; Ruppel, C.D.

    2002-01-01

    Using von Herzen and Maxwell's needle probe method, we measured thermal conductivity in four porous mixtures of quartz sand and methane gas hydrate, with hydrate composing 0, 33, 67 and 100% of the solid volume. Thermal conductivities were measured at a constant methane pore pressure of 24.8 MPa between -20 and +15??C, and at a constant temperature of -10??C between 3.5 and 27.6 MPa methane pore pressure. Thermal conductivity decreased with increasing temperature and increased with increasing methane pore pressure. Both dependencies weakened with increasing hydrate content. Despite the high thermal conductivity of quartz relative to methane hydrate, the largest thermal conductivity was measured in the mixture containing 33% hydrate rather than in hydrate-free sand. This suggests gas hydrate enhanced grain-to-grain heat transfer, perhaps due to intergranular contact growth during hydrate synthesis. These results for gas-filled porous mixtures can help constrain thermal conductivity estimates in porous, gas hydrate-bearing systems.

  13. Surface energy budget and thermal inertia at Gale Crater: Calculations from ground-based measurements.

    Science.gov (United States)

    Martínez, G M; Rennó, N; Fischer, E; Borlina, C S; Hallet, B; de la Torre Juárez, M; Vasavada, A R; Ramos, M; Hamilton, V; Gomez-Elvira, J; Haberle, R M

    2014-08-01

    The analysis of the surface energy budget (SEB) yields insights into soil-atmosphere interactions and local climates, while the analysis of the thermal inertia ( I ) of shallow subsurfaces provides context for evaluating geological features. Mars orbital data have been used to determine thermal inertias at horizontal scales of ∼10 4  m 2 to ∼10 7  m 2 . Here we use measurements of ground temperature and atmospheric variables by Curiosity to calculate thermal inertias at Gale Crater at horizontal scales of ∼10 2  m 2 . We analyze three sols representing distinct environmental conditions and soil properties, sol 82 at Rocknest (RCK), sol 112 at Point Lake (PL), and sol 139 at Yellowknife Bay (YKB). Our results indicate that the largest thermal inertia I  = 452 J m -2  K -1  s -1/2 (SI units used throughout this article) is found at YKB followed by PL with I  = 306 and RCK with I  = 295. These values are consistent with the expected thermal inertias for the types of terrain imaged by Mastcam and with previous satellite estimations at Gale Crater. We also calculate the SEB using data from measurements by Curiosity's Rover Environmental Monitoring Station and dust opacity values derived from measurements by Mastcam. The knowledge of the SEB and thermal inertia has the potential to enhance our understanding of the climate, the geology, and the habitability of Mars.

  14. Advanced Sine Wave Modulation of Continuous Wave Laser System for Atmospheric CO2 Differential Absorption Measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.

    2014-01-01

    NASA Langley Research Center in collaboration with ITT Exelis have been experimenting with Continuous Wave (CW) laser absorption spectrometer (LAS) as a means of performing atmospheric CO2 column measurements from space to support the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission.Because range resolving Intensity Modulated (IM) CW lidar techniques presented here rely on matched filter correlations, autocorrelation properties without side lobes or other artifacts are highly desirable since the autocorrelation function is critical for the measurements of lidar return powers, laser path lengths, and CO2 column amounts. In this paper modulation techniques are investigated that improve autocorrelation properties. The modulation techniques investigated in this paper include sine waves modulated by maximum length (ML) sequences in various hardware configurations. A CW lidar system using sine waves modulated by ML pseudo random noise codes is described, which uses a time shifting approach to separate channels and make multiple, simultaneous online/offline differential absorption measurements. Unlike the pure ML sequence, this technique is useful in hardware that is band pass filtered as the IM sine wave carrier shifts the main power band. Both amplitude and Phase Shift Keying (PSK) modulated IM carriers are investigated that exibit perfect autocorrelation properties down to one cycle per code bit. In addition, a method is presented to bandwidth limit the ML sequence based on a Gaussian filter implemented in terms of Jacobi theta functions that does not seriously degrade the resolution or introduce side lobes as a means of reducing aliasing and IM carrier bandwidth.

  15. Measurement of βeff in the coupled fast-thermal system HERBE

    International Nuclear Information System (INIS)

    Milosevic, M.; Pesic, M.; Avdic, S.

    1994-01-01

    The delayed neutron parameters and methods used in reactor safety studies are verified by measurement of the effective delayed neutron fraction β eff in the coupled fast-thermal system HERBE. The HERBE system is strongly heterogeneous. Methods applied in the calculation and interpretation of β eff measurement are described. The measured and calculated quantities and estimated uncertainties are presented. Agreement between the computation and measurement suggests the validity of the calculation method

  16. Thermal surface characteristics of coal fires 1 results of in-situ measurements

    Science.gov (United States)

    Zhang, Jianzhong; Kuenzer, Claudia

    2007-12-01

    Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO 2 and - under certain circumstances - to spontaneous combustion. Coal fires occur in many countries world wide - however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N 2O). They additionally contribute to the emission of green house relevant gasses such as CO 2 and CH 4 to the atmosphere. In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered. Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime

  17. Thermal and Optical Modulation of the Carrier Mobility in OTFTs Based on an Azo-anthracene Liquid Crystal Organic Semiconductor.

    Science.gov (United States)

    Chen, Yantong; Li, Chao; Xu, Xiuru; Liu, Ming; He, Yaowu; Murtaza, Imran; Zhang, Dongwei; Yao, Chao; Wang, Yongfeng; Meng, Hong

    2017-03-01

    One of the most striking features of organic semiconductors compared with their corresponding inorganic counterparts is their molecular diversity. The major challenge in organic semiconductor material technology is creating molecular structural motifs to develop multifunctional materials in order to achieve the desired functionalities yet to optimize the specific device performance. Azo-compounds, because of their special photoresponsive property, have attracted extensive interest in photonic and optoelectronic applications; if incorporated wisely in the organic semiconductor groups, they can be innovatively utilized in advanced smart electronic applications, where thermal and photo modulation is applied to tune the electronic properties. On the basis of this aspiration, a novel azo-functionalized liquid crystal semiconductor material, (E)-1-(4-(anthracen-2-yl)phenyl)-2-(4-(decyloxy)phenyl)diazene (APDPD), is designed and synthesized for application in organic thin-film transistors (OTFTs). The UV-vis spectra of APDPD exhibit reversible photoisomerizaton upon photoexcitation, and the thin films of APDPD show a long-range orientational order based on its liquid crystal phase. The performance of OTFTs based on this material as well as the effects of thermal treatment and UV-irradiation on mobility are investigated. The molecular structure, stability of the material, and morphology of the thin films are characterized by thermal gravimetric analysis (TGA), polarizing optical microscopy (POM), (differential scanning calorimetry (DSC), UV-vis spectroscopy, atomic force microscopy (AFM), and scanning tunneling microscopy (STM). This study reveals that our new material has the potential to be applied in optical sensors, memories, logic circuits, and functional switches.

  18. Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 160A

    International Nuclear Information System (INIS)

    Walker, B. J.; Miller, D. T.

    2017-01-01

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 160A which were measured by the Radiation Measurements Laboratory (RML).

  19. Opto-thermal moisture content and moisture depth profile measurements in organic materials

    NARCIS (Netherlands)

    Xiao, P.; Guo, X.; Cui, Y.Y.; Imhof, R.; Bicanic, D.D.

    2004-01-01

    Opto-thermal transient emission radiometry(OTTER) is a infrared remote sensing technique, which has been successfully used in in vivo skin moisture content and skin moisture depth profiling measurements.In present paper, we extend this moisture content measurement capability to analyze the moisture

  20. Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 160A

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, D. T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-06

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 160A which were measured by the Radiation Measurements Laboratory (RML).