Effects of Post Heat Treatments on ZnO Thin-Films Grown on Zn-coated Teflon Substrates

Energy Technology Data Exchange (ETDEWEB)

Kim, Ikhyun; Nam, Giwoong; Lee, Cheoleon; Kim, Dongwhan; Choi, Hyonkwang; Kim, Yangsoo; Leem, Jae-Young [Inje University, Gimhae (Korea, Republic of); Kim, Jin Soo [Chonbuk National University, Jeonju (Korea, Republic of); Kim, Jong Su [Yeungnam University, Gyeongsan (Korea, Republic of); Son, Jeong-Sik [Kyungwoon University, Gumi (Korea, Republic of)

2015-06-15

ZnO thin films were first grown on Zn-coated Teflon substrates using a spin-coating method, with various post-heating temperatures. The structural and optical properties of the ZnO thin films were then investigated using field-effect scanning-electron microscopy, X-ray diffractometry, and photoluminescence (PL) spectroscopy. The surface morphology of these ZnO thin films exhibited dendritic structures. With increasing post-heating temperature, all samples preferentially exhibited preferential c-axis orientation and increased residual tensile stress. All of the films exhibited preferential c-axis orientation, and the residual tensile stress of those increased with increasing post-heating temperature. The near-band-edge emission (NBE) peaks were red-shifted after post-heating treatment at 400 ℃. The intensity of the deep-level emission (DLE) peaks gradually decreased with increasing post- heating temperature. Moreover, the narrowest ‘full width at half maximum’ (FWHM) and the highest intensity ratio of the NBE to the DLE for thin films, were observed after post-heating at 400 ℃. The ZnO thin films fabricated with the 400 ℃ post-heating process provided the highest crystallinity and optical properties.

Significant questions in thin liquid film heat transfer

International Nuclear Information System (INIS)

Bankoff, S.G.

1994-01-01

Thin liquid films appear in many contexts, such as the cooling of gas turbine blade tips, rocket engines, microelectronics arrays, and hot fuel element surfaces in hypothetical nuclear reactor accidents. Apart from these direct cooling applications of thin liquid layers, thin films form a crucial element in determining the allowable heat flux limits in boiling. This is because the last stages of dryout almost invariably involve the rupture of a residual liquid film, either as a microlayer underneath the bubbles, or a thin annular layer in a high-quality burnout scenario. The destabilization of these thin films under the combined actions of shear stress, evaporation, and thermocapillary effects is quite complex. The later stages of actual rupture to form dry regions, which then expand, resulting in possible overheating, are even more complex and less well understood. However, significant progress has been made in understanding the behavior of these thin films, which are subject to competing instabilities prior to actual rupture. This will be reviewed briefly. Recent work on the advance, or recession, of contact lines will also be described briefly, and significant questions that still remain to be answered will be discussed. 68 refs., 7 figs

Ultrahigh Flux Thin Film Boiling Heat Transfer Through Nanoporous Membranes.

Science.gov (United States)

Wang, Qingyang; Chen, Renkun

2018-05-09

Phase change heat transfer is fundamentally important for thermal energy conversion and management, such as in electronics with power density over 1 kW/cm 2 . The critical heat flux (CHF) of phase change heat transfer, either evaporation or boiling, is limited by vapor flux from the liquid-vapor interface, known as the upper limit of heat flux. This limit could in theory be greater than 1 kW/cm 2 on a planar surface, but its experimental realization has remained elusive. Here, we utilized nanoporous membranes to realize a new "thin film boiling" regime that resulted in an unprecedentedly high CHF of over 1.2 kW/cm 2 on a planar surface, which is within a factor of 4 of the theoretical limit, and can be increased to a higher value if mechanical strength of the membranes can be improved (demonstrated with 1.85 kW/cm 2 CHF in this work). The liquid supply is achieved through a simple nanoporous membrane that supports the liquid film where its thickness automatically decreases as heat flux increases. The thin film configuration reduces the conductive thermal resistance, leads to high frequency bubble departure, and provides separate liquid-vapor pathways, therefore significantly enhances the heat transfer. Our work provides a new nanostructuring approach to achieve ultrahigh heat flux in phase change heat transfer and will benefit both theoretical understanding and application in thermal management of high power devices of boiling heat transfer.

Heat wave propagation in a thin film irradiated by ultra-short laser pulses

International Nuclear Information System (INIS)

Yoo, Jae Gwon; Kim, Cheol Jung; Lim, C. H.

2004-01-01

A thermal wave solution of a hyperbolic heat conduction equation in a thin film is developed on the basis of the Green's function formalism. Numerical computations are carried out to investigate the temperature response and the propagation of the thermal wave inside a thin film due to a heat pulse generated by ultra-short laser pulses with various laser pulse durations and thickness of the film

Specific heat measurement set-up for quench condensed thin superconducting films.

Science.gov (United States)

Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

2014-05-01

We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

Measuring and predicting the dynamic effects of a confined thin metal plate pulse heated into the liquid-vapor regime

International Nuclear Information System (INIS)

Baxter, R.C.

1977-01-01

The dynamic response of a confined thin layer of lead heated rapidly and uniformly to a supercritical state was investigated. Lead targets 0.025 mm and 0.05 mm thick were contained between a thin titanium tamping layer and a thick layer of fused quartz with several different gap widths between the lead and the confining surfaces. After being heated by an electron beam for about 50 ns, lead specimens expanded to a state of approximately half liquid and half vapor. Measurements of the stress in the quartz and the velocity of the tamper produced by the expanding lead were compared with one dimensional hydrodynamic computer program predictions. Measured and predicted peak stresses in the quartz for no gaps were approximately 12 kilobars and agreed within one kilobar. Peak stresses decreased rapidly with gap size to values, at 0.02 mm gaps, of about one kilobar for the 0.025 mm lead targets and five kilobars for the 0.05 mm targets. These values were confirmed by measurements. Predictions and measurements of tamper velocity (momentum) were within 10% only when the lead and confining walls were in close contact. The observed velocities for even very small gaps were substantially below predictions. These differences are attributed primarily to separation of the liquid and vapor phases during the expansion

Enhancement of Heat and Mass Transfer in Mechanically Contstrained Ultra Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kevin Drost; Jim Liburdy; Brian Paul; Richard Peterson

2005-01-01

Oregon State University (OSU) and the Pacific Northwest National Laboratory (PNNL) were funded by the U.S. Department of Energy to conduct research focused on resolving the key technical issues that limited the deployment of efficient and extremely compact microtechnology based heat actuated absorption heat pumps and gas absorbers. Success in demonstrating these technologies will reduce the main barriers to the deployment of a technology that can significantly reduce energy consumption in the building, automotive and industrial sectors while providing a technology that can improve our ability to sequester CO{sub 2}. The proposed research cost $939,477. $539,477 of the proposed amount funded research conducted at OSU while the balance ($400,000) was used at PNNL. The project lasted 42 months and started in April 2001. Recent developments at the Pacific Northwest National Laboratory and Oregon State University suggest that the performance of absorption and desorption systems can be significantly enhanced by the use of an ultra-thin film gas/liquid contactor. This device employs microtechnology-based structures to mechanically constrain the gas/liquid interface. This technology can be used to form very thin liquid films with a film thickness less then 100 microns while still allowing gas/liquid contact. When the resistance to mass transfer in gas desorption and absorption is dominated by diffusion in the liquid phase the use of extremely thin films (<100 microns) for desorption and absorption can radically reduce the size of a gas desorber or absorber. The development of compact absorbers and desorbers enables the deployment of small heat-actuated absorption heat pumps for distributed space heating and cooling applications, heat-actuated automotive air conditioning, manportable cooling, gas absorption units for the chemical process industry and the development of high capacity CO{sub 2} absorption devices for CO{sub 2} collection and sequestration. The energy

Initial verification of an induction heating set-up for injection molding

DEFF Research Database (Denmark)

Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

2013-01-01

Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object...... selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured...

Heat treatment and aging effect on the structural and optical properties of plasma polymerized 2,6-diethylaniline thin films

International Nuclear Information System (INIS)

Matin, Rummana; Bhuiyan, A.H.

2012-01-01

The monomer, 2,6-diethylaniline has been used to deposit plasma polymerized 2,6-diethylaniline (PPDEA) thin films at room temperature on to glass substrates by a capacitively coupled parallel plate glow discharge reactor. A comparative analysis on the changes of morphological, structural and optical properties of as-deposited, heat treated and aged PPDEA thin films is ascertained. Scanning electron microscopy shows uniform and pinhole free surface of PPDEA thin films and no significant difference in the surface morphology is observed due to heat treatment. Electron dispersive X-ray and Fourier transform infrared spectroscopic investigations indicate some structural rearrangement in PPDEA thin films due to heat treatment. Differential thermal analysis, thermogravimetric analysis and differential thermogravimetric analysis suggest that the PPDEA is thermally stable up to about 580 K. The study on the optical absorption spectra of as-deposited, heat treated and aged PPDEA thin films of different thicknesses lead to the determination of the allowed direct and indirect transition energies ranging from 3.63 to 2.73 and 2.38 to 1.26 eV respectively. Urbach energy, steepness parameter and extinction coefficient are also assessed. It is observed that the optical parameters of as-deposited PPDEA thin films change due to heat treatment and do not change appreciably due to aging. - Highlights: ► Heat treatment and aging effect of plasma polymerized 2,6-diethylaniline thin films. ► The surface morphology of PPDEA is found uniform for all types of sample. ► Heat treatment introduces some elemental and structural rearrangement. ► The thermal stability is found up to about 580 K. ► Optical parameters were changed for heat treatment but not markedly for aging.

Homotopy Perturbation Method for Thin Film Flow and Heat Transfer over an Unsteady Stretching Sheet with Internal Heating and Variable Heat Flux

Directory of Open Access Journals (Sweden)

I-Chung Liu

2012-01-01

Full Text Available We have analyzed the effects of variable heat flux and internal heat generation on the flow and heat transfer in a thin film on a horizontal sheet in the presence of thermal radiation. Similarity transformations are used to transform the governing equations to a set of coupled nonlinear ordinary differential equations. The obtained differential equations are solved approximately by the homotopy perturbation method (HPM. The effects of various parameters governing the flow and heat transfer in this study are discussed and presented graphically. Comparison of numerical results is made with the earlier published results under limiting cases.

Enhancement and Tunability of Near-Field Radiative Heat Transfer Mediated by Surface Plasmon Polaritons in Thin Plasmonic Films

Directory of Open Access Journals (Sweden)

Svetlana V. Boriskina

2015-06-01

Full Text Available The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength of thermal radiation. Using a rigorous fluctuational electrodynamics approach, we predict that ultra-thin films of plasmonic materials can be used to dramatically enhance near-field heat transfer. The total spectrally integrated film-to-film heat transfer is over an order of magnitude larger than between the same materials in bulk form and also exceeds the levels achievable with polar dielectrics such as SiC. We attribute this enhancement to the significant spectral broadening of radiative heat transfer due to coupling between surface plasmon polaritons (SPPs on both sides of each thin film. We show that the radiative heat flux spectrum can be further shaped by the choice of the substrate onto which the thin film is deposited. In particular, substrates supporting surface phonon polaritons (SPhP strongly modify the heat flux spectrum owing to the interactions between SPPs on thin films and SPhPs of the substrate. The use of thin film phase change materials on polar dielectric substrates allows for dynamic switching of the heat flux spectrum between SPP-mediated and SPhP-mediated peaks.

Characterization of a high performance ultra-thin heat pipe cooling module for mobile hand held electronic devices

Science.gov (United States)

Ahamed, Mohammad Shahed; Saito, Yuji; Mashiko, Koichi; Mochizuki, Masataka

2017-11-01

In recent years, heat pipes have been widely used in various hand held mobile electronic devices such as smart phones, tablet PCs, digital cameras. With the development of technology these devices have different user friendly features and applications; which require very high clock speeds of the processor. In general, a high clock speed generates a lot of heat, which needs to be spreaded or removed to eliminate the hot spot on the processor surface. However, it is a challenging task to achieve proper cooling of such electronic devices mentioned above because of their confined spaces and concentrated heat sources. Regarding this challenge, we introduced an ultra-thin heat pipe; this heat pipe consists of a special fiber wick structure named as "Center Fiber Wick" which can provide sufficient vapor space on the both sides of the wick structure. We also developed a cooling module that uses this kind of ultra-thin heat pipe to eliminate the hot spot issue. This cooling module consists of an ultra-thin heat pipe and a metal plate. By changing the width, the flattened thickness and the effective length of the ultra-thin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module. In addition, other experiments were also conducted to determine the effects of changes in the number of heat pipes in a single module. Characterization and comparison of the module have also been conducted both experimentally and theoretically.

Rapid thermal annealing of Ti-rich TiNi thin films: A new approach to fabricate patterned shape memory thin films

International Nuclear Information System (INIS)

Motemani, Y.; Tan, M.J.; White, T.J.; Huang, W.M.

2011-01-01

This paper reports the rapid thermal annealing (RTA) of Ti-rich TiNi thin films, synthesized by the co-sputtering of TiNi and Ti targets. Long-range order of aperiodic alloy could be achieved in a few seconds with the optimum temperature of 773 K. Longer annealing (773 K/240 s), transformed the film to a poorly ordered vitreous phase, suggesting a novel method for solid state amorphization. Reitveld refinement analyses showed significant differences in structural parameters of the films crystallized by rapid and conventional thermal annealing. Dependence of the elastic modulus on the valence electron density (VED) of the crystallized films was studied. It is suggested that RTA provides a new approach to fabricate patterned shape memory thin films.

Shock-induced thermal wave propagation and response analysis of a viscoelastic thin plate under transient heating loads

Science.gov (United States)

Li, Chenlin; Guo, Huili; Tian, Xiaogeng

2018-04-01

This paper is devoted to the thermal shock analysis for viscoelastic materials under transient heating loads. The governing coupled equations with time-delay parameter and nonlocal scale parameter are derived based on the generalized thermo-viscoelasticity theory. The problem of a thin plate composed of viscoelastic material, subjected to a sudden temperature rise at the boundary plane, is solved by employing Laplace transformation techniques. The transient responses, i.e. temperature, displacement, stresses, heat flux as well as strain, are obtained and discussed. The effects of time-delay and nonlocal scale parameter on the transient responses are analyzed and discussed. It can be observed that: the propagation of thermal wave is dynamically smoothed and changed with the variation of time-delay; while the displacement, strain, and stress can be rapidly reduced by nonlocal scale parameter, which can be viewed as an important indicator for predicting the stiffness softening behavior for viscoelastic materials.

Thin absorbers for large-area soft X-ray microcalorimeters

Energy Technology Data Exchange (ETDEWEB)

Rocks, L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)]. E-mail: rocks@wisp.physics.wisc.edu; Anderson, M.B. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bilgri, N. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Brekosky, R. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gwynne Crowder, S. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Figueroa-Feliciano, E. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lai, T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Lindeman, M.A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Man, J. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); McCammon, D. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Nelms, K.L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Porter, F.S. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sivananthan, S. [University of Illinois at Chicago, Chicago, IL 60607 (United States); Vidugiris, G. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Zhao, J. [University of Illinois at Chicago, Chicago, IL 60607 (United States)

2006-04-15

The X-ray Quantum Calorimeter (XQC) sounding rocket experiment utilizes a microcalorimeter array for observing the diffuse soft X-ray background. Observations of such low surface-brightness targets require a large-area detector. We will be using an array of large absorbers. Good absorbers must rapidly and completely thermalize photons, have small heat capacity for high stopping efficiency and have good lateral thermal transport. For observing the soft X-ray background (energies <1 keV), the volume and heat capacity of absorber material can be kept to a minimum by making the absorbers only as thick as needed for high quantum efficiency at these low energies. These thin, large-area absorbers are not self-supporting and have poor lateral heat transport. Depositing the absorber material on a Si substrate provides support and improves lateral thermal conduction. We present heat capacity results for thin HgTe and thin Bi, each on Si substrates. We also describe the HgTe absorber fabrication.

Improved damp heat stability of Ga-Doped ZnO thin film by pretreatment of the polyethylene terephthalate substrate

Science.gov (United States)

Kim, B. B.; Seo, S. G.; Lim, Y. S.; Choi, H.-S.; Seo, W.-S.; Park, H.-H.

2013-09-01

A study on the damp heat stability of transparent conducting ZnO thin film grown on a polyethylene terephthalate substrate (PET) is reported. By thermal annealing of the PET substrate at 100°C with Ar flow in a vacuum chamber prior to the sputtering growth of Ga-doped ZnO (GZO) thin film, significantly enhanced damp heat stability was achieved at 60°C with a 90% relative humidity. Electrical and structural characterizations of the GZO thin films were carried out and the effects of the pretreatment on the improved damp heat stability are discussed.

Implantable polymer/metal thin film structures for the localized treatment of cancer by Joule heating

Science.gov (United States)

Kan-Dapaah, Kwabena; Rahbar, Nima; Theriault, Christian; Soboyejo, Wole

2015-04-01

This paper presents an implantable polymer/metal alloy thin film structure for localized post-operative treatment of breast cancer. A combination of experiments and models is used to study the temperature changes due to Joule heating by patterned metallic thin films embedded in poly-dimethylsiloxane. The heat conduction within the device and the surrounding normal/cancerous breast tissue is modeled with three-dimensional finite element method (FEM). The FEM simulations are used to explore the potential effects of device geometry and Joule heating on the temperature distribution and lesion (thermal dose). The FEM model is validated using a gel model that mimics biological media. The predictions are also compared to prior results from in vitro studies and relevant in vivo studies in the literature. The implications of the results are discussed for the potential application of polymer/metal thin film structures in hyperthermic treatment of cancer.

Terminal project heat convection in thin cylinders

International Nuclear Information System (INIS)

Morales Corona, J.

1992-01-01

Heat convection in thin cylinders and analysis about natural convection for straight vertical plates, and straight vertical cylinders submersed in a fluid are presented some works carry out by different authors in the field of heat transfer. In the part of conduction, deduction of the equation of heat conduction in cylindrical coordinates by means of energy balance in a control volume is presented. Enthalpy and internal energy are used for the outlining of the equation and finally the equation in its vectorial form is obtained. In the convection part development to calculate the Nusselt number for a straight vertical plate by a forces analysis, an energy balance and mass conservation over a control volume is outlined. Several empiric correlations to calculate the Nusselt number and its relations with other dimensionless numbers are presented. In the experimental part the way in which a prototype rode is assembled is presented measurements of temperatures attained in steady state and in free convection for working fluids as air and water are showed in tables. Also graphs of Nusselt numbers obtained in the experimental way through some empiric correlations are showed (Author)

Investigation of stacked elemental layers for Cu(In,Ga)Se{sub 2} thin film preparation by rapid thermal selenization

Energy Technology Data Exchange (ETDEWEB)

Stroth, Christiane; Ohland, Joerg; Mikolajczak, Ulf; Madena, Thomas; Keller, Jan; Parisi, Juergen; Hammer, Maria; Riedel, Ingo [Energy and Semiconductor Research Laboratory, Department of Physics, University of Oldenburg, 26111 Oldenburg (Germany)

2013-07-01

Rapid thermal selenization of pure metallic (Cu-In-Ga) or selenium-containing (Cu-In-Ga-Se) precursors is a favorable method to fabricate Cu(In,Ga)Se{sub 2} absorber films for application in thin film solar cells. Because of its upscaling potential and the short process time it is a promising approach for the fabrication of CIGSe photovoltaic modules on industrial scale. As a preliminary work for prospective plasma-enhanced selenization of stacked elemental layers (SEL) the elements copper, indium and gallium were sequentially deposited on molybdenum coated soda-lime glass by thermal evaporation. The stacking order was varied and the precursors were annealed with different heating rates. Morphology, elemental depth distribution and phases of the layers were investigated before and after annealing using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Furthermore the influence of different heating rates on phase transitions during annealing was studied by in-situ X-ray diffraction.

Rapid preparation of solution-processed InGaZnO thin films by microwave annealing and photoirradiation

International Nuclear Information System (INIS)

Cheong, Heajeong; Ogura, Shintaro; Ushijima, Hirobumi; Yoshida, Manabu; Fukuda, Nobuko; Uemura, Sei

2015-01-01

We fabricated solution-processed indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs) by microwave (MW) annealing an IGZO precursor film followed by irradiating with vacuum ultraviolet (VUV) light. MW annealing allows more rapid heating of the precursor film than conventional annealing processes using a hot plate or electric oven and promotes the crystallization of IGZO. VUV irradiation was used to reduce the duration and temperature of the post-annealing step. Consequently, the IGZO TFTs fabricated through MW annealing for 5 min and VUV irradiation for 1 min exhibited an on/off current ratio of 10 8 and a field-effect mobility of 0.3 cm 2  V −1  s −1 . These results indicate that MW annealing and photoirradiation is an effective combination for annealing solution processed IGZO precursor films to prepare the semiconductor layers of TFTs

ITO thin films prepared by a microwave heating

International Nuclear Information System (INIS)

Okuya, Masayuki; Ito, Nobuyuki; Shiozaki, Katsuyuki

2007-01-01

ITO thin films were prepared by irradiating 2.45 GHz of microwave with an output power of 700 W using a commercial kitchen microwave oven. A substrate temperature went up and down rapidly between 100 and 650 deg. C in a minute by a dielectric loss of SnO 2 layer pre-deposited on a glass substrate. We found that the electrical and optical properties of films were affected by the atmosphere in a microwave irradiation, while the sintering was completed within a few minutes. Although the electrical resistivity was not reduced below 5.0 x 10 -4 Ω.cm in this study, the results lead to the possibility of a practical rapid synthesis of ITO transparent conducting oxide films

Rapid preparation of solution-processed InGaZnO thin films by microwave annealing and photoirradiation

Energy Technology Data Exchange (ETDEWEB)

Cheong, Heajeong; Ogura, Shintaro; Ushijima, Hirobumi; Yoshida, Manabu; Fukuda, Nobuko; Uemura, Sei, E-mail: sei-uemura@aist.go.jp [Flexible Electronics Research Center (FLEC), National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

2015-06-15

We fabricated solution-processed indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs) by microwave (MW) annealing an IGZO precursor film followed by irradiating with vacuum ultraviolet (VUV) light. MW annealing allows more rapid heating of the precursor film than conventional annealing processes using a hot plate or electric oven and promotes the crystallization of IGZO. VUV irradiation was used to reduce the duration and temperature of the post-annealing step. Consequently, the IGZO TFTs fabricated through MW annealing for 5 min and VUV irradiation for 1 min exhibited an on/off current ratio of 10{sup 8} and a field-effect mobility of 0.3 cm{sup 2} V{sup −1} s{sup −1}. These results indicate that MW annealing and photoirradiation is an effective combination for annealing solution processed IGZO precursor films to prepare the semiconductor layers of TFTs.

Simultaneous measurement of thermal conductivity and heat capacity of bulk and thin film materials using frequency-dependent transient thermoreflectance method.

Science.gov (United States)

Liu, Jun; Zhu, Jie; Tian, Miao; Gu, Xiaokun; Schmidt, Aaron; Yang, Ronggui

2013-03-01

The increasing interest in the extraordinary thermal properties of nanostructures has led to the development of various measurement techniques. Transient thermoreflectance method has emerged as a reliable measurement technique for thermal conductivity of thin films. In this method, the determination of thermal conductivity usually relies much on the accuracy of heat capacity input. For new nanoscale materials with unknown or less-understood thermal properties, it is either questionable to assume bulk heat capacity for nanostructures or difficult to obtain the bulk form of those materials for a conventional heat capacity measurement. In this paper, we describe a technique for simultaneous measurement of thermal conductivity κ and volumetric heat capacity C of both bulk and thin film materials using frequency-dependent time-domain thermoreflectance (TDTR) signals. The heat transfer model is analyzed first to find how different combinations of κ and C determine the frequency-dependent TDTR signals. Simultaneous measurement of thermal conductivity and volumetric heat capacity is then demonstrated with bulk Si and thin film SiO2 samples using frequency-dependent TDTR measurement. This method is further testified by measuring both thermal conductivity and volumetric heat capacity of novel hybrid organic-inorganic thin films fabricated using the atomic∕molecular layer deposition. Simultaneous measurement of thermal conductivity and heat capacity can significantly shorten the development∕discovery cycle of novel materials.

Heat transfer fouling characteristics of microfiltered thin stillage from the dry grind process.

Science.gov (United States)

Arora, Amit; Dien, Bruce S; Belyea, Ronald L; Singh, Vijay; Tumbleson, M E; Rausch, Kent D

2010-08-01

We investigated effects of microfiltration (MF) on heat transfer fouling tendencies of thin stillage. A stainless steel MF membrane (0.1 micron pore size) was used to remove solids from thin stillage. At filtration conditions of 690kPa, the MF process effectively recovered total solids from thin stillage. Thin stillage was concentrated from 7.0% to 22.4% solids with average permeate flux rates of 180+/-30 L/m(2)/h at 75 degrees C. In retentate streams, protein and fat contents were increased from 23.5 and 16.7% db to 27.6 and 31.1% db, respectively, and ash content was reduced from 10.5% to 3.8% db. Removal of solids, protein and fat generated a microfiltration permeate (MFP) that was used as an input stream to the fouling probe system; MFP fouling tendencies were measured. An annular fouling probe was used to measure fouling tendencies of thin stillage from a commercial dry grind facility. When comparing diluted thin stillage (DTS) stream and MFP, a reduction in solids concentration was not the only reason of fouling decrement. Selective removal of protein and fat played an important role in mitigating the fouling. At t=10h, mean fouling rates of MFP were an order of magnitude lower when compared to thin stillage and diluted streams. When maximum probe temperature (200 degrees C) was reached, mean fouling rates for thin stillage, DTS and MFP were 7.1x10(-4), 4.2x10(-4) and 2.6x10(-4) m(2) degrees C/kW/min, respectively. In DTS and MFP, the induction period was prolonged by factors of 4.3 and 9.5, respectively, compared to the induction period for thin stillage fouling. Mean fouling rates were decreased by factors of 2.3 and 23.4 for DTS and MFP, respectively. Fouling of MFP took twice the time to reach a probe temperature of 200 degrees C than did thin stillage (22 h vs 10 h, respectively). A reduction in heat transfer fouling could be achieved by altering process stream composition using microfiltration. Copyright 2010 Elsevier Ltd. All rights reserved.

On the characteristics and application of thin wall welded titanium tubes for heat transfer

International Nuclear Information System (INIS)

Nishimura, Takashi; Miyamoto, Yoshiyuki

1985-01-01

Because of the excellent corrosion resistance, thin wall welded titanium tubes have become to be used in large number as the heat transfer tubes of condensers and seawater desalting plants using seawater in place of conventional copper alloy tubes. Especially in nuclear power plants, the all titanium condensers using thin wall welded titanium tubes and titanium tube plates were adopted in the almost all plants under construction or expected to be constructed. In this report, the various characteristics of thin wall welded titanium tubes required for using them as heat transfer tubes, such as corrosion resistance, heat transfer characteristics, fatigue strength and expanding characteristics, are outlined, and the state of use is described. At first, relatively thick seamless titanium tubes were used for chemical industry, but thereafter, due to the advance of the mass production techniques, the welded titanium tubes of less than 0.7 mm thickness and high quality have become to be supplied at low cost. In 1969, titanium tubes were used for the first time in Japan for the air cooler in the condenser of Akita Power Station, Tohoku Electric Power Co., Inc. The features of titanium are small specific gravity, small linear expansion coefficient and small Young's modulus. (Kako, I.)

Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute

Energy Technology Data Exchange (ETDEWEB)

Xu, Ting; Kao, Joseph

2016-11-08

Functional nanocomposites containing nanoparticles of different chemical compositions may exhibit new properties to meet demands for advanced technology. It is imperative to simultaneously achieve hierarchical structural control and to develop rapid, scalable fabrication to minimize degradation of nanoparticle properties and for compatibility with nanomanufacturing. The assembly kinetics of supramolecular nanocomposite in thin films is governed by the energetic cost arising from defects, the chain mobility, and the activation energy for inter-domain diffusion. By optimizing only one parameter, the solvent fraction in the film, the assembly kinetics can be precisely tailored to produce hierarchically structured thin films of supramolecular nanocomposites in approximately one minute. Moreover, the strong wavelength dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present invention opens a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films.

Rapid onset of squamous cell carcinoma in a thin skin graft donor site.

Science.gov (United States)

Herard, C; Arnaud, D; Goga, D; Rousseau, P; Potier, B

2016-01-01

Squamous cell carcinomas are malignant tumours of epithelial origin that can appear on sites subjected to chronic inflammation after a period of several years. The rapid development of squamous cell carcinoma at the donor site for a thin skin graft is a rare and poorly understood situation. We report the case of a patient undergoing thin skin grafting to cover the area of removal of a vertex squamous cell carcinoma and in whom squamous cell carcinoma appeared at the donor site within 9 weeks. In our case, we ruled out intraoperative contamination because two sets of surgical instruments were used. Given the number of cases reported in the literature, a chance event seems unlikely. The hypothesis of an acute inflammatory process caused by scarring of the thin skin graft site appears to us the most convincing. Development of cancer at the graft donor site may thus be added to the list of complications of thin skin grafting. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

Energy Technology Data Exchange (ETDEWEB)

Grapes, Michael D., E-mail: mgrapes1@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Friedman, Lawrence H.; LaVan, David A., E-mail: david.lavan@nist.gov [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2014-08-15

Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

Acoustically enhanced heat transport

Energy Technology Data Exchange (ETDEWEB)

Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)

2016-01-15

We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

A novel high performance, ultra thin heat sink for electronics

International Nuclear Information System (INIS)

Escher, W.; Michel, B.; Poulikakos, D.

2010-01-01

We present an ultra thin heat sink for electronics, combining optimized impinging slot-jets, micro-channels and manifolds for efficient cooling. We first introduce a three-dimensional numerical model of the heat transfer structure, to investigate its hydrodynamic and thermal performance and its sensitivity to geometric parameters. In a second step we propose a three-dimensional hydrodynamic numerical model representing the complete system. Based on this model we design a novel manifold providing uniform fluid distribution. In order to save computational time a simpler semi-empirical model is proposed and validated. The semi-empirical model allows a robust optimization of the heat sink geometric parameters. The design is optimized for a 2 x 2 cm 2 chip and provides a total thermal resistance of 0.087 cm 2 K/W for flow rates 2 for a temperature difference between fluid inlet and chip of 65 K.

Thermal and mechanical effect during rapid heating of astroloy for improving structural integrity

International Nuclear Information System (INIS)

Popoolaa, A.P.I.; Oluwasegun, K.M.; Olorunniwo, O.E.; Atanda, P.O.; Aigbodion, V.S.

2016-01-01

The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astroloy(Turbine Disc alloy) a Powder metallurgy (PM) nickel base superalloy has been investigated. The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ) microstructure of an inertia friction welded Astroloy were simulated using a Gleeble thermo-mechanical simulation system. Detailed microstructural examination of the simulated TMAZ and HAZ and those present in actual inertial friction welded specimens showed that γ′ particles persisted during rapid heating up to a temperature where the formation of liquid is thermodynamically favoured, and subsequently re-solidified eutectically. The result obtained showed that forging during the thermo-mechanical simulation significantly enhanced resistance to weld liquation cracking of the alloy. This is attributable to strain-induced rapid isothermal dissolution of the constitutional liquation products within 150 μm from the centre of the forged sample. This was not observed in purely thermally simulated samples. The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens. - Highlights: • The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astrology • The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ). • significantly enhanced resistance to weld liquation cracking of the alloy. • This was not observed in purely thermally simulated samples. • The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens.

Thermal and mechanical effect during rapid heating of astroloy for improving structural integrity

Energy Technology Data Exchange (ETDEWEB)

Popoolaa, A.P.I., E-mail: popoolaapi@tut.ac.za [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Oluwasegun, K.M. [Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Olorunniwo, O.E., E-mail: segun_nniwo@yahoo.com [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Atanda, P.O. [Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Aigbodion, V.S. [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Metallurgical and Materials Engineering, University of Nigeria, Nsukka (Nigeria)

2016-05-05

The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astroloy(Turbine Disc alloy) a Powder metallurgy (PM) nickel base superalloy has been investigated. The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ) microstructure of an inertia friction welded Astroloy were simulated using a Gleeble thermo-mechanical simulation system. Detailed microstructural examination of the simulated TMAZ and HAZ and those present in actual inertial friction welded specimens showed that γ′ particles persisted during rapid heating up to a temperature where the formation of liquid is thermodynamically favoured, and subsequently re-solidified eutectically. The result obtained showed that forging during the thermo-mechanical simulation significantly enhanced resistance to weld liquation cracking of the alloy. This is attributable to strain-induced rapid isothermal dissolution of the constitutional liquation products within 150 μm from the centre of the forged sample. This was not observed in purely thermally simulated samples. The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens. - Highlights: • The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astrology • The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ). • significantly enhanced resistance to weld liquation cracking of the alloy. • This was not observed in purely thermally simulated samples. • The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens.

Preparation of RF reactively sputtered indium-tin oxide thin films with optical properties suitable for heat mirrors

International Nuclear Information System (INIS)

Boyadzhiev, S; Dobrikov, G; Rassovska, M

2008-01-01

Technologies are discussed for preparing and characterizing indium-tin oxide (ITO) thin films with properties appropriate for usage as heat mirrors in solar thermal collectors. The samples were prepared by means of radio frequency (RF) reactive sputtering of indium-tin targets in oxygen. The technological parameters were optimized to obtain films with optimal properties for heat mirrors. The optical properties of the films were studied by visible and infra-red (IR) spectrophotometry and laser ellipsometry. The reflectance of the films in the thermal IR range was investigated by a Fourier transform infra-red (FTIR) spectrophotometer. Heating of the substrates during the sputtering and their post deposition annealing in different environments were also studied. The ultimate purpose of the present research being the development of a technological process leading to low-cost ITO thin films with high transparency in the visible and near IR (0.3-2.4 μm) and high reflection in the thermal IR range (2.5-25 μm), we investigated the correlation of the ITO thin films structural and optical properties with the technological process parameters - target composition and heat treatment

Improvement of formability for fabricating thin continuously corrugated structures in sheet metal forming process

International Nuclear Information System (INIS)

Choi, Sung Woo; Park, Sang Hu; Park, Seong Hun; Ha, Man Yeong; Jeong, Ho Seung; Cho, Jong Rae

2012-01-01

A stamping process is widely used for fabricating various sheet metal parts for vehicles, airplanes, and electronic devices by the merit of low processing cost and high productivity. Recently, the use of thin sheets with a corrugated structure for sheet metal parts has rapidly increased for use in energy management devices, such as heat exchangers, separators in fuel cells, and many others. However, it is not easy to make thin corrugated structures directly using a single step stamping process due to their geometrical complexity and very thin thickness. To solve this problem, a multi step stamping (MSS) process that includes a heat treatment process to improve formability is proposed in this work: the sequential process is the initial stamping, heat treatment, and final shaping. By the proposed method, we achieved successful results in fabricating thin corrugated structures with an average thickness of 75μm and increased formability of about 31% compared to the single step stamping process. Such structures can be used in a plate-type heat exchanger requiring low weight and a compact shape

Rapid self-heating and internal temperature sensing of lithium-ion batteries at low temperatures

International Nuclear Information System (INIS)

Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Yang, Xiao-Guang; Tian, Hua; Wang, Chao-Yang

2016-01-01

Highlights: • Self-heating lithium-ion battery (SHLB) structure provided a practical solution to the poor performance at subzero temperatures. • We report an improved SHLB that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than previously reported. • The nickel foil heating element embedded inside a SHLB cell plays a dominant role in rapid self-heating. • The embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS). • 2-sheet design self-heats faster than 1-sheet design due to more uniform internal temperature distribution. - Abstract: The recently discovered self-heating lithium-ion battery structure provided a practical solution to the poor performance at subzero temperatures that has hampered battery technology for decades. Here we report an improved self-heating lithium-ion battery (SHLB) that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than that reported previously. We reveal that a nickel foil heating element embedded inside a SHLB cell plays a dominant role in self-heating and we experimentally demonstrate that a 2-sheet design can achieve dramatically accelerated self-heating due to more uniform internal temperature distribution. We also report, for the first time, that this embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS) due to the perfectly linear relationship between the foil’s electrical resistance and temperature.

A Rapid Method for Deposition of Sn-Doped GaN Thin Films on Glass and Polyethylene Terephthalate Substrates

Science.gov (United States)

Pat, Suat; Özen, Soner; Korkmaz, Şadan

2018-01-01

We report the influence of Sn doping on microstructure, surface, and optical properties of GaN thin films deposited on glass and polyethylene terephthalate (PET) substrate. Sn-doped GaN thin films have been deposited by thermionic vacuum arc (TVA) at low temperature. TVA is a rapid deposition technology for thin film growth. Surface and optical properties of the thin films were presented. Grain size, height distribution, roughness values were determined. Grain sizes were calculated as 20 nm and 13 nm for glass and PET substrates, respectively. Nano crystalline forms were shown by field emission scanning electron microscopy. Optical band gap values were determined by optical methods and photoluminescence measurement. The optical band gap values of Sn doped GaN on glass and PET were determined to be approximately ˜3.40 eV and ˜3.47 eV, respectively. As a result, TVA is a rapid and low temperature deposition technology for the Sn doped GaN deposited on glass and PET substrate.

Rapid thinning and collapse of lake calving Yakutat Glacier, Southeast Alaska

Science.gov (United States)

Trussel, Barbara Lea

Glaciers around the globe are experiencing a notable retreat and thinning, triggered by atmospheric warming. Tidewater glaciers in particular have received much attention, because they have been recognized to contribute substantially to global sea level rise. However, lake calving glaciers in Alaska show increasingly high thinning and retreat rates and are therefore contributors to sea level rise. The number of such lake calving systems is increasing worldwide as land-terminating glaciers retreat into overdeepened basins and form proglacial lakes. Yakutat Glacier in Southeast Alaska is a low elevation lake calving glacier with an accumulation to total area ratio of 0.03. It experienced rapid thinning of 4.43 +/- 0.06 m w.e. yr-1 between 2000-2010 and terminus retreat of over 15 km since the beginning of the 20th century. Simultaneously, adjacent Yakutat Icefield land-terminating glaciers thinned at lower but still substantial rates (3.54 +/- 0.06 m w.e. yr -1 for the same time period), indicating lake calving dynamics help drive increased mass loss. Yakutat Glacier sustained a ˜3 km long floating tongue for over a decade, which started to disintegrate into large tabular icebergs in 2010. Such floating tongues are rarely seen on temperate tidewater glaciers. The floating ice was weakened by surface ablation, which then allowed rifts to form and intersect. Ice velocity from GPS measurements showed that the ice on the floating tongue was moving substantially faster than grounded ice, which was attributed to rift opening between the floating and grounded ice. Temporal variations of rift opening were determined from time-lapse imagery, and correlated well with variations in ice speeds. Larger rift opening rates occurred during and after precipitation or increased melt episodes. Both of these events increased subglacial discharge and could potentially increase the subaqueous currents towards the open lake and thus increase drag on the ice underside. Simultaneously

Characteristics of rapid-thermal-annealed LiCoO2 cathode film for an all-solid-state thin film microbattery

International Nuclear Information System (INIS)

Kim, Han-Ki; Yoon, Young Soo

2004-01-01

We report on the fabrication of a LiCoO 2 film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The LiCoO 2 films were grown by rf magnetron sputtering using a synthesized LiCoO 2 target in a [O 2 /(Ar+O 2 )] ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited LiCoO 2 film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed LiCoO 2 film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm2 μm. These results show the possibility of the RTA LiCoO 2 film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively

Rapid charging of thermal energy storage materials through plasmonic heating.

Science.gov (United States)

Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

2014-09-01

Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

Rapid IV Versus Oral Rehydration: Responses to Subsequent Exercise Heat Stress

National Research Council Canada - National Science Library

Kenefick, Robert W; O'Moore, Kathleen M; Mahood, Nicholas V; Castellani, John W

2006-01-01

This study sought to determine the effect of rapid intravenous (IV) versus oral (ORAL) rehydration immediately after dehydration, on cardiovascular, thermoregulatory, and perceptual responses during subsequent exercise in the heat.

Standard Test Method for Measuring Heat Transfer Rate Using a Thin-Skin Calorimeter

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 This test method covers the design and use of a thin metallic calorimeter for measuring heat transfer rate (also called heat flux). Thermocouples are attached to the unexposed surface of the calorimeter. A one-dimensional heat flow analysis is used for calculating the heat transfer rate from the temperature measurements. Applications include aerodynamic heating, laser and radiation power measurements, and fire safety testing. 1.2 Advantages 1.2.1 Simplicity of ConstructionThe calorimeter may be constructed from a number of materials. The size and shape can often be made to match the actual application. Thermocouples may be attached to the metal by spot, electron beam, or laser welding. 1.2.2 Heat transfer rate distributions may be obtained if metals with low thermal conductivity, such as some stainless steels, are used. 1.2.3 The calorimeters can be fabricated with smooth surfaces, without insulators or plugs and the attendant temperature discontinuities, to provide more realistic flow conditions for ...

Functional Design of Dielectric-Metal-Dielectric-Based Thin-Film Encapsulation with Heat Transfer and Flexibility for Flexible Displays.

Science.gov (United States)

Kwon, Jeong Hyun; Choi, Seungyeop; Jeon, Yongmin; Kim, Hyuncheol; Chang, Ki Soo; Choi, Kyung Cheol

2017-08-16

In this study, a new and efficient dielectric-metal-dielectric-based thin-film encapsulation (DMD-TFE) with an inserted Ag thin film is proposed to guarantee the reliability of flexible displays by improving the barrier properties, mechanical flexibility, and heat dissipation, which are considered to be essential requirements for organic light-emitting diode (OLED) encapsulation. The DMD-TFE, which is composed of Al 2 O 3 , Ag, and a silica nanoparticle-embedded sol-gel hybrid nanocomposite, shows a water vapor transmission rate of 8.70 × 10 -6 g/m 2 /day and good mechanical reliability at a bending radius of 30 mm, corresponding to 0.41% strain for 1000 bending cycles. The electrical performance of a thin-film encapsulated phosphorescent organic light-emitting diode (PHOLED) was identical to that of a glass-lid encapsulated PHOLED. The operational lifetimes of the thin-film encapsulated and glass-lid encapsulated PHOLEDs are 832 and 754 h, respectively. After 80 days, the thin-film encapsulated PHOLED did not show performance degradation or dark spots on the cell image in a shelf-lifetime test. Finally, the difference in lifetime of the OLED devices in relation to the presence and thickness of a Ag film was analyzed by applying various TFE structures to fluorescent organic light-emitting diodes (FOLEDs) that could generate high amounts of heat. To demonstrate the difference in heat dissipation effect among the TFE structures, the saturated temperatures of the encapsulated FOLEDs were measured from the back side surface of the glass substrate, and were found to be 67.78, 65.12, 60.44, and 39.67 °C after all encapsulated FOLEDs were operated at an initial luminance of 10 000 cd/m 2 for sufficient heat generation. Furthermore, the operational lifetime tests of the encapsulated FOLED devices showed results that were consistent with the measurements of real-time temperature profiles taken with an infrared camera. A multifunctional hybrid thin-film encapsulation

Heat Transfer to a Thin Solid Combustible in Flame Spreading at Microgravity

Science.gov (United States)

Bhattacharjee, S.; Altenkirch, R. A.; Olson, S. L.; Sotos, R. G.

1991-01-01

The heat transfer rate to a thin solid combustible from an attached diffusion flame, spreading across the surface of the combustible in a quiescent, microgravity environment, was determined from measurements made in the drop tower facility at NASA-Lewis Research Center. With first-order Arrhenius pyrolysis kinetics, the solid-phase mass and energy equations along with the measured spread rate and surface temperature profiles were used to calculate the net heat flux to the surface. Results of the measurements are compared to the numerical solution of the complete set of coupled differential equations that describes the temperature, species, and velocity fields in the gas and solid phases. The theory and experiment agree on the major qualitative features of the heat transfer. Some fundamental differences are attributed to the neglect of radiation in the theoretical model.

Grain Growth in Nanocrystalline Mg-Al Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kruska, Karen; Rohatgi, Aashish; Vemuri, Venkata Rama Ses; Kovarik, Libor; Moser, Trevor H.; Evans, James E.; Browning, Nigel D.

2017-10-05

An improved understanding of grain growth kinetics in nanocrystalline materials, and in metals and alloys in general, is of continuing interest to the scientific community. In this study, Mg - Al thin films containing ~10 wt.% Al and with 14.5 nm average grain size were produced by magnetron-sputtering and subjected to heat-treatments. The grain growth evolution in the early stages of heat treatment at 423 K (150 °C), 473 K (200 °C) and 573K (300 °C) was observed with transmission electron microscopy and analyzed based upon the classical equation developed by Burke and Turnbull. The grain growth exponent was found to be 7±2 and the activation energy for grain growth was 31.1±13.4 kJ/mol, the latter being significantly lower than in bulk Mg-Al alloys. The observed grain growth kinetics are explained by the Al supersaturation in the matrix and the pinning effects of the rapidly forming beta precipitates and possibly shallow grain boundary grooves. The low activation energy is attributed to the rapid surface diffusion which is dominant in thin film systems.

Numerical Simulation of Vapor Bubble Growth and Heat Transfer in a Thin Liquid Film

International Nuclear Information System (INIS)

Yu-Jia, Tao; Xiu-Lan, Huai; Zhi-Gang, Li

2009-01-01

A mathematical model is developed to investigate the dynamics of vapor bubble growth in a thin liquid film, movement of the interface between two fluids and the surface heat transfer characteristics. The model takes into account the effects of phase change between the vapor and liquid, gravity, surface tension and viscosity. The details of the multiphase now and heat transfer are discussed for two cases: (1) when a water micro-droplet impacts a thin liquid film with a vapor bubble growing and (2) when the vapor bubble grows and merges with the vapor layer above the liquid film without the droplet impacting. The development trend of the interface between the vapor and liquid is coincident qualitatively with the available literature, mostly at the first stage. We also provide an important method to better understand the mechanism of nucleate spray cooling. (fundamental areas of phenomenology (including applications))

The Structural Changes of the Sn(y)OX Thin Films Under Influence of Heat Treament

Science.gov (United States)

Vong, V.

2001-04-01

Composite oxide Sn(y) Ox made by thermal oxidation of the Sn(y)-bimetal thin films, in which y is the doped-materials as well as Sb, Ag or Pd. The Sn(y)-bimetal thin films have been made by evaporation in high vacuum onto NaCl-monocrystall and optical glass substrates. In the work the tin and the doped material (y) were put on two different boats and then both the boats were simultaniously heated to evaporate. The Sn(y)Ox thin films were annealed at the differential temperatures. The structural changes of its have been investigated by using X-ray diffraction and transmission electron microscope.

Preparation of silicon carbide nanowires via a rapid heating process

International Nuclear Information System (INIS)

Li Xintong; Chen Xiaohong; Song Huaihe

2011-01-01

Silicon carbide (SiC) nanowires were fabricated in a large quantity by a rapid heating carbothermal reduction of a novel resorcinol-formaldehyde (RF)/SiO 2 hybrid aerogel in this study. SiC nanowires were grown at 1500 deg. C for 2 h in an argon atmosphere without any catalyst via vapor-solid (V-S) process. The β-SiC nanowires were characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM) equipped with energy dispersive X-ray (EDX) facility, Fourier transformed infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The analysis results show that the aspect ratio of the SiC nanowires via the rapid heating process is much larger than that of the sample produced via gradual heating process. The SiC nanowires are single crystalline β-SiC phase with diameters of about 20-80 nm and lengths of about several tens of micrometers, growing along the [1 1 1] direction with a fringe spacing of 0.25 nm. The role of the interpenetrating network of RF/SiO 2 hybrid aerogel in the carbothermal reduction was discussed and the possible growth mechanism of the nanowires is analyzed.

Influence of heat conducting substrates on explosive crystallization in thin layers

Science.gov (United States)

Schneider, Wilhelm

2017-09-01

Crystallization in a thin, initially amorphous layer is considered. The layer is in thermal contact with a substrate of very large dimensions. The energy equation of the layer contains source and sink terms. The source term is due to liberation of latent heat in the crystallization process, while the sink term is due to conduction of heat into the substrate. To determine the latter, the heat diffusion equation for the substrate is solved by applying Duhamel's integral. Thus, the energy equation of the layer becomes a heat diffusion equation with a time integral as an additional term. The latter term indicates that the heat loss due to the substrate depends on the history of the process. To complete the set of equations, the crystallization process is described by a rate equation for the degree of crystallization. The governing equations are then transformed to a moving co-ordinate system in order to analyze crystallization waves that propagate with invariant properties. Dual solutions are found by an asymptotic expansion for large activation energies of molecular diffusion. By introducing suitable variables, the results can be presented in a universal form that comprises the influence of all non-dimensional parameters that govern the process. Of particular interest for applications is the prediction of a critical heat loss parameter for the existence of crystallization waves with invariant properties.

Transparent conductive Ta2O5-codoped ITO thin films prepared by different heating process

International Nuclear Information System (INIS)

Zhang, B.; Dong, X.P.; Wu, J.S.; Xu, X.F.

2008-01-01

Tantalum-doped indium tin oxide thin films were deposited by a cosputtering technique with an ITO target and a Ta 2 O 5 target. The variations of microstructure, electrical and optical properties with substrate temperature and annealing temperature were investigated in some detail. Ta-doped ITO thin films showed better crystalline structure with different prominent plane orientation by different heating process. ITO:Ta thin films deposited at room temperature showed better optical and electrical properties. Increasing substrate temperature and reasonable annealing temperature could remarkably improve the optical and electrical properties of the films. The variation of carrier concentration had an important influence on near-IR reflection, near-UV absorption and optical bandgap. ITO:Ta thin films showed wider optical bandgap. ITO:Ta thin films under the optimum parameters had a sheet resistance of 10-20 and ohm;/sq and a transmittance of 85% with an optical bandgap of above 4.0 eV. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

Science.gov (United States)

Kal, S.; Kasko, I.; Ryssel, H.

1995-10-01

The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (micrographs of the ion-beam mixed and unmixed CoSi2 films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

Numerical modeling of heat transfer during hydrogen absorption in thin double-layered annular ZrCo beds

Science.gov (United States)

Cui, Yehui; Zeng, Xiangguo; Kou, Huaqin; Ding, Jun; Wang, Fang

2018-06-01

In this work a three-dimensional (3D) hydrogen absorption model was proposed to study the heat transfer behavior in thin double-layered annular ZrCo beds. Numerical simulations were performed to investigate the effects of conversion layer thickness, thermal conductivity, cooling medium and its flow velocity on the efficiency of heat transfer. Results reveal that decreasing the layer thickness and improving the thermal conductivity enhance the ability of heat transfer. Compared with nitrogen and helium, water appears to be a better medium for cooling. In order to achieve the best efficiency of heat transfer, the flow velocity needs to be maximized.

Rapid shift in thermal resistance between generations through maternal heat exposure

NARCIS (Netherlands)

Zizzari, Z.V.; Ellers, J.

2014-01-01

Given the current rapid climate change, understanding the mechanisms underlying heat tolerance and its plasticity is an important goal of global change biology. Soil fauna communities are especially vulnerable because of their limited dispersal ability. It is generally recognized that

Phonon and electron temperature and non-Fourier heat transport in thin layers

Energy Technology Data Exchange (ETDEWEB)

Carlomagno, I.; Cimmelli, V.A. [Department of Mathematics, Computer Science and Economics, University of Basilicata, Campus Macchia Romana, Viale dell' Ateneo Lucano 10, 85100 Potenza (Italy); Sellitto, A. [Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (Italy)

2017-04-15

We present a thermodynamic model of heat conductor which allows for different temperatures of phonons and electrons. This model is applied to calculate the steady-state radial temperature profile in a circular thin layer. The compatibility of the obtained temperature profiles with the second law of thermodynamics is investigated in view of the requirement of positive entropy production and of a nonlocal constitutive equation for the entropy flux.

Numerical modeling of heat transfer during hydrogen absorption in thin double-layered annular ZrCo beds

Directory of Open Access Journals (Sweden)

Yehui Cui

2018-06-01

Full Text Available In this work a three-dimensional (3D hydrogen absorption model was proposed to study the heat transfer behavior in thin double-layered annular ZrCo beds. Numerical simulations were performed to investigate the effects of conversion layer thickness, thermal conductivity, cooling medium and its flow velocity on the efficiency of heat transfer. Results reveal that decreasing the layer thickness and improving the thermal conductivity enhance the ability of heat transfer. Compared with nitrogen and helium, water appears to be a better medium for cooling. In order to achieve the best efficiency of heat transfer, the flow velocity needs to be maximized. Keywords: Hydrogen storage, ZrCo metal hydride, Heat transfer, Three-dimensional simulation

Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

Science.gov (United States)

Felker, Daniel L.; Burggraf, Larry W.

2014-01-01

Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

Reversible p-type conductivity in H passivated nitrogen and phosphorous codoped ZnO thin films using rapid thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Mannam, Ramanjaneyulu, E-mail: ramu.nov9@gmail.com [Department of Physics, Nano Functional Materials Technology Centre and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600036 (India); Kumar, E. Senthil [SRM Research Institute, Department of Physics and Nanotechnology, SRM University, Kattankulathur 603203, Tamil Nadu (India); DasGupta, Nandita [Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600036 (India); Ramachandra Rao, M.S., E-mail: msrrao@iitm.ac.in [Department of Physics, Nano Functional Materials Technology Centre and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600036 (India)

2017-04-01

Highlights: • Electrical transport measurements revel that the (P, N) codoped ZnO thin films exhibited change in conductivity from p-type to n-type over a span of 120 days. • Hydrogen and carbon are found to be the main unintentional impurities in n-type (P, N) codoped ZnO thin films. • Rapid thermal annealing has been used to remove both H and C from the films. • Carbon can be removed at an annealing temperature of 600 °C, whereas, the dissociation of N−H complex takes place only at 800 °C. • The n-type (P, N) codoped ZnO thin film exhibited change in conductivity to p-type at an annealing temperature of 800 °C. - Abstract: We demonstrate reversible p-type nature of pulsed laser deposited (P, N) codoped ZnO thin films using rapid thermal annealing process. As grown thin films exhibited change in conductivity from p to n-type over a span of 120 days. Non-annealed n-type thin films contain unintentional donor impurities such as hydrogen and carbon. X-ray photoelectron spectroscopy and Raman measurements conclusively show that hydrogen passivates nitrogen acceptors by forming N−H complex. Carbon can be annealed out at 600 °C, whereas, the dissociation of N−H complex takes place at 800 °C. The films revert its p-type nature at an annealing temperature of 800 °C.

Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

Directory of Open Access Journals (Sweden)

Burungale Vishal V.

2016-03-01

Full Text Available Rapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

Nonlinear periodic wavetrains in thin liquid films falling on a uniformly heated horizontal plate

Science.gov (United States)

Issokolo, Remi J. Noumana; Dikandé, Alain M.

2018-05-01

A thin liquid film falling on a uniformly heated horizontal plate spreads into fingering ripples that can display a complex dynamics ranging from continuous waves, nonlinear spatially localized periodic wave patterns (i.e., rivulet structures) to modulated nonlinear wavetrain structures. Some of these structures have been observed experimentally; however, conditions under which they form are still not well understood. In this work, we examine profiles of nonlinear wave patterns formed by a thin liquid film falling on a uniformly heated horizontal plate. For this purpose, the Benney model is considered assuming a uniform temperature distribution along the film propagation on the horizontal surface. It is shown that for strong surface tension but a relatively small Biot number, spatially localized periodic-wave structures can be analytically obtained by solving the governing equation under appropriate conditions. In the regime of weak nonlinearity, a multiple-scale expansion combined with the reductive perturbation method leads to a complex Ginzburg-Landau equation: the solutions of which are modulated periodic pulse trains which amplitude and width and period are expressed in terms of characteristic parameters of the model.

Review of Critical Heat Flux Correlations for Upward Flow in a Vertical Thin Rectangular Channel

International Nuclear Information System (INIS)

Choi, Gil Sik; Chang, Soon Heung

2014-01-01

From the view point of safety, this type of fuel has higher resistance to earthquake and external impact. The cross section of coolant flow channel in the reactor core composed with the plate fuel is a thin rectangular shape. Thermal-hydraulic characteristics of this thin rectangular channel are different with those of general circular rod fuel bundle flow channel. Accordingly it could be thought that the CHF correlation in a thin rectangular channel is different with that in a circular channel, for which a large number of researches on CHF prediction have been carried out. The objective of this paper is to review previous researches on CHF in a thin rectangular channel, summarize the important conclusion and propose the new simple CHF correlation, which is based on the data set under high pressure and high flow rate condition. The researches on CHF in rectangular channel have been partially carried out according to the pressure, heated surface number, heated surface wettability effect, flow driving force and flow direction conditions. From the literature researches on CHF for upward flow in a vertical thin rectangular channel, some CHF prediction methods were reviewed and compared. There is no universal correlation which can predict CHF at all conditions, but generally, Katto empirical correlation is known to be useful at high pressure and high flow rate. The new simple correlation was developed from the restricted data set, the CHF prediction capacity of which is better than that of Katto. Even though the prediction consistency of the new simple correlation is lower, MAE and RMS error decreased quite. For the more development of the new simple CHF correlation, the more advanced regression analysis method and theoretical analysis should be studied in future

Review of Critical Heat Flux Correlations for Upward Flow in a Vertical Thin Rectangular Channel

Energy Technology Data Exchange (ETDEWEB)

Choi, Gil Sik; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-05-15

From the view point of safety, this type of fuel has higher resistance to earthquake and external impact. The cross section of coolant flow channel in the reactor core composed with the plate fuel is a thin rectangular shape. Thermal-hydraulic characteristics of this thin rectangular channel are different with those of general circular rod fuel bundle flow channel. Accordingly it could be thought that the CHF correlation in a thin rectangular channel is different with that in a circular channel, for which a large number of researches on CHF prediction have been carried out. The objective of this paper is to review previous researches on CHF in a thin rectangular channel, summarize the important conclusion and propose the new simple CHF correlation, which is based on the data set under high pressure and high flow rate condition. The researches on CHF in rectangular channel have been partially carried out according to the pressure, heated surface number, heated surface wettability effect, flow driving force and flow direction conditions. From the literature researches on CHF for upward flow in a vertical thin rectangular channel, some CHF prediction methods were reviewed and compared. There is no universal correlation which can predict CHF at all conditions, but generally, Katto empirical correlation is known to be useful at high pressure and high flow rate. The new simple correlation was developed from the restricted data set, the CHF prediction capacity of which is better than that of Katto. Even though the prediction consistency of the new simple correlation is lower, MAE and RMS error decreased quite. For the more development of the new simple CHF correlation, the more advanced regression analysis method and theoretical analysis should be studied in future.

Heat and fluid flow during rapid solidification of non-equilibrium materials

International Nuclear Information System (INIS)

Negli, S.C.; Eddingfield, D.L.; Brower, W.E. Jr.

1990-01-01

Rapid solidification technology (RST) is an advanced solidification process which is being utilized to produce non-equilibrium structures with properties not previously available with conventionally cast materials. An iron based alloy rapidly quenched to form a metallic glass is being installed on a large scale in electric power transformers where it cuts heat losses dramatically. The formation of a non-equilibrium structure usually requires a cooling rate of at least a million degrees per second. Achieving this high a cooling rate depends not only on the heat transfer conditions during the quenching process, but also on the fluid flow conditions in the molten metal before and during solidification. This paper presents a model of both heat and fluid flow during RST by the hammer and anvil method. The symmetry of two sided cooling permits analysis which is still applicable to the one sided cooling that occurs during melt spinning, the prevalent method of RST. The heat flow is modeled as one dimensional, normal to the quench surface. Previous models have shown the heat flow in the plane of the quench surface not to be significant. The fluid flow portion of the model utilizes the squeeze film solution for flow between two parallel flat plates. The model predicts the effects of superheat of the melt and of the quench hammer speed upon cooling rate during the formation of nonequilibrium phases. An unexpected result is that increased superheat results in much higher cooling rates, due to fluid flow before a potential transformation would take place; this enhanced liquid metal flow results in a thinner section casting which in turn has a dominant effect on the cooling rate. The model also predicts an expanded regime of Newtonian (interface controlled) cooling by about a factor of ten as compared to previous model of RST

Application of rapid thermal processing on SiNx thin film to solar cells

Institute of Scientific and Technical Information of China (English)

Youjie LI; Peiqing LUO; Zhibin ZHOU; Rongqiang CUI; Jianhua HUANG; Jingxiao WANG

2008-01-01

Rapid thermal processing (RTP) of SiNx thin films from PECVD with low temperature was investigated. A special processing condition of this technique which could greatly increase the minority lifetime was found in the experiments. The processing mechanism and the application of the technique to silicon solar cells fabrication were dis-cussed. A main achievement is an increase of the minority lifetime in silicon wafer with SiNx thin film by about 200% after the RTP was reached. PC-1D simulation results exhibit an enhancement of the efficiency of the solar cell by 0.42% coming from the minority lifetime improvement. The same experiment was also conducted with P-diffusion silicon wafers, but the increment of minority lifetime is just about 55%. It could be expected to improve the solar cell efficiency if it would be used in silicon solar cells fabrication with the combination of laser firing contact technique.

Enhanced heat transfer in partially open square cavities with thin fin by using electric field

International Nuclear Information System (INIS)

Kasayapanand, N.; Kiatsiriroat, T.

2009-01-01

Numerical modeling of the electric field effect on the natural convection in the partially open square cavities with thin fin attached is investigated. The interactions among electric, flow, and temperature fields are analyzed by using a computational fluid dynamics technique. It is found that the flow and heat transfer enhancements are a decreasing function of the Rayleigh number. Moreover, the volume flow rate and heat transfer coefficient are substantially improved by electrohydrodynamic especially at low aperture size, high aperture position, and high inclined angle. Surprisingly, the maximum convective heat transfer is obtained at the minimum electrical energy consumption by placing electrodes at a suitable position. The optimum electrode arrangements for both single fin and multiple fins are also achieved

Developing a theoretical model to investigate thermal performance of a thin membrane heat-pipe solar collector

International Nuclear Information System (INIS)

Riffat, S.B.; Zhao, X.; Doherty, P.S.

2005-01-01

A thin membrane heat-pipe solar collector was designed and constructed to allow heat from solar radiation to be collected at a relatively high efficiency while keeping the capital cost low. A theoretical model incorporating a set of heat balance equations was developed to analyse heat transfer processes occurring in separate regions of the collector, i.e., the top cover, absorber and condenser/manifold areas, and examine their relationship. The thermal performance of the collector was investigated using the theoretical model. The modelling predictions were validated using the experimental data from a referred source. The test efficiency was found to be in the range 40-70%, which is a bitter lower than the values predicted by modelling. The factors influencing these results were investigated

Rapid heating of Alaska pollock and chicken breast myofibrillar protein gels as affecting water-holding properties.

Science.gov (United States)

Stevenson, Clinton D; Liu, Wenjie; Lanier, Tyre C

2012-10-10

The gelation response of salted muscle minces to rapid versus slow heating rates is thought to differ between homeotherm and poikilotherm species. This study investigated water-holding (WH) properties of pastes prepared from refined myofibrils, at equal pH, of chicken breast versus Alaska pollock both during [cook loss (CL)] and following [expressible water (EW)] their cooking by rapid [microwave (MW)] versus slow [water bath (WB)] heating and whether such properties were related to gel matrix structure parameters and water mobility. Results did not confirm the industrial experience that pastes of meat from homeotherms benefit from slower cooking. Gels of equally high WH ability (low CL or EW) were made by rapid heating when the holding time did not exceed 5 min prior to cooling, which was sufficient for completion of gelation. Reduced CL and EW correlated with larger and smaller amplitudes of T21 and T22 water pools, respectively, measured by time-domain nuclear magnetic resonance (TD-NMR).

Rapid Holocene thinning of outlet glaciers followed by readvance in the western Ross Embayment, Antarctica

Science.gov (United States)

Jones, R. S.; Whitmore, R.; Mackintosh, A.; Norton, K. P.; Eaves, S.; Stutz, J.

2017-12-01

Investigating Antarctic deglaciation following the LGM provides an opportunity to better understand patterns, mechanisms and drivers of ice sheet retreat. In the Ross Sea sector, geomorphic features preserved on the seafloor indicate that streaming East Antarctic outlet glaciers once extended >100 km offshore of South Victoria Land prior to back-stepping towards their modern configurations. In order to adequately interpret the style and causes of this retreat, the timing and magnitude of corresponding ice thickness change is required. We present new constraints on ice surface lowering from Mawson Glacier, an outlet of the East Antarctic Ice Sheet that flows into the western Ross Sea. Surface-exposure (10Be) ages from samples collected in elevation transects above the modern ice surface reveal that rapid thinning occurred at 5-8 ka, broadly coeval with new ages of grounding-line retreat at 6 ka and rapid thinning recorded at nearby Mackay Glacier at 7 ka. Our data also show that a moraine formed near to the modern ice margin of Mawson Glacier at 0.8 ka, which, together with historical observations, indicates that glaciers in this region readvanced during the last thousand years. We argue that 1) the accelerated thinning of outlet glaciers was driven by local grounding-line retreat through overdeepened basins during the early-mid Holocene, and 2) the glaciers subsequently readvanced, possibly linked to late Holocene sea-ice expansion, before retreating to their current positions. Our work demonstrates that these outlet glaciers were closely coupled to environmental and topography-induced perturbations near their termini throughout the Holocene.

Current-induced metal-insulator transition in VO x thin film prepared by rapid-thermal-annealing

International Nuclear Information System (INIS)

Cho, Choong-Rae; Cho, SungIl; Vadim, Sidorkin; Jung, Ranju; Yoo, Inkyeong

2006-01-01

The phenomenon of metal-insulator transition (MIT) in polycrystalline VO x thin films and their preparations have been studied. The films were prepared by sputtering of vanadium thin films succeeded by Rapid Thermal Annealing (RTA) in oxygen ambient at 500 deg. C. Crystalline, compositional, and morphological characterizations reveal a continuous change of phase from vanadium metal to the highest oxide phase, V 2 O 5 , with the time of annealing. Electrical MIT switching has been observed in these films. Sweeping mode, electrode area, and temperature dependent MIT has been studied in Pt/VO x /Pt vertical structure. The important parameters for MIT in VO x have been found to be the current density and the electric field, which depend on carrier density in the films

Orientation of rapid thermally annealed lead zirconate titanate thin films on (111) Pt substrate

International Nuclear Information System (INIS)

Brooks, K.G.; Reaney, I.M.; Klissurska, R.; Huang, Y.; Bursill, L.A.; Setter, N.

1994-01-01

The nucleation, growth and orientation of lead zirconate titanate thin films prepared from organometallic precursor solutions by spin coating on (111) oriented platinum substrates and crystallized by rapid thermal annealing was investigated. The effects of pyrolysis temperature, post-pyrolysis thermal treatments, excess lead addition, and Nb dopant substitution are reported. The use of post pyrolysis oxygen anneals at temperatures in the regime of 350-450 deg C was found to strongly effect the kinetics of subsequent amorphous-pyrochlore perovskite crystallization by rapid thermal annealing. It has also allowed films of reproducible microstructure and textures (both (100) and (111)) to be prepared by rapid thermal annealing. It is suggested that such anneals and pyrolysis temperature affect the oxygen concentration/average Pb valence in the amorphous films prior to annealing. The changes in Pb valence state then affect the stability of the transient pyrochlore phase and thus the kinetics of perovskite crystallization. Nb dopant was also found to influence the crystallization kinetics. 28 refs., 18 figs

Determination of crystal growth rates during rapid solidification of polycrystalline aluminum by nano-scale spatio-temporal resolution in situ transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Zweiacker, K., E-mail: Kai@zweiacker.org; Liu, C.; Wiezorek, J. M. K. [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 648 Benedum Hall, 3700 OHara Street, Pittsburgh, Pennsylvania 15261 (United States); McKeown, J. T.; LaGrange, T.; Reed, B. W.; Campbell, G. H. [Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551 (United States)

2016-08-07

In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of the metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ∼1.3 m s{sup −1} to ∼2.5 m s{sup −1} during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s{sup −1} have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. Using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.

Strain-tempering of low carbon martensite steel wire by rapid heating

International Nuclear Information System (INIS)

Torisaka, Yasunori; Kihara, Junji

1978-01-01

In the production of prestressed concrete steel wires, a series of the cold drawing-patenting process are performed to improve the strength. In order to reduce cyclic process, the low carbon martensite steel wire which can be produced only by the process of hot rolling and direct quench has been investigated as strain-tempering material. When strain-tempering is performed on the low carbon martensite steel wire, stress relaxation (Re%) increases and mechanical properties such as total elongation, reduction of area, ultimate tensile strength and proof stress decrease remarkably by annealing. In order to shorten the heating time, the authors performed on the steel wire the strain-tempering with a heating time of 1.0 s using direct electrical resistance heating and examined the effects of rapid heating on the stress relaxation and the mechanical properties. Stress relaxation decreases without impairment of the mechanical properties up to a strain-tempering temperature of 573 K. Re(%) after 10.8 ks is 0% at the testing temperature 301 K, 0.49% at 363 K and 1.39% at 433 K. (auth.)

Coupling of near-field thermal radiative heating and phonon Monte Carlo simulation: Assessment of temperature gradient in n-doped silicon thin film

International Nuclear Information System (INIS)

Wong, Basil T.; Francoeur, Mathieu; Bong, Victor N.-S.; Mengüç, M. Pinar

2014-01-01

Near-field thermal radiative exchange between two objects is typically more effective than the far-field thermal radiative exchange as the heat flux can increase up to several orders higher in magnitudes due to tunneling of evanescent waves. Such an interesting phenomenon has started to gain its popularity in nanotechnology, especially in nano-gap thermophotovoltaic systems and near-field radiative cooling of micro-/nano-devices. Here, we explored the existence of thermal gradient within an n-doped silicon thin film when it is subjected to intensive near-field thermal radiative heating. The near-field radiative power density deposited within the film is calculated using the Maxwell equations combined with fluctuational electrodynamics. A phonon Monte Carlo simulation is then used to assess the temperature gradient by treating the near-field radiative power density as the heat source. Results indicated that it is improbable to have temperature gradient with the near-field radiative heating as a continuous source unless the source comprises of ultra-short radiative pulses with a strong power density. - Highlights: • This study investigates temperature distribution in an n-doped silicon thin film. • Near-field radiative heating is treated as a volumetric phenomenon. • The temperature gradient is computed using phonon MC simulation. • Temperature of thin film can be approximated as uniform for radiation calculations. • If heat source is a pulsed radiation, a temperature gradient can be established

Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates

DEFF Research Database (Denmark)

Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

2013-01-01

, char properties, measured at room temperature, were dependent on the preceding storage conditions (in air or in a desiccator). The char was found to have the highest mechanical strength against compression in the outer crust facing the heat source. For thin (147μm) free coating films, a tendency...... with respect to the mechanical resistance against compression, degree of expansion, and residual mass fraction. Experimental results show that when using this type of shock heating, the mechanical resistance of the char against compression cannot meaningfully be correlated to the expansion factor. In addition...

Prediction of Experimental Surface Heat Flux of Thin Film Gauges using ANFIS

Science.gov (United States)

Sarma, Shrutidhara; Sahoo, Niranjan; Unal, Aynur

2018-05-01

Precise quantification of surface heat fluxes in highly transient environment is of paramount importance from the design point of view of several engineering equipment like thermal protection or cooling systems. Such environments are simulated in experimental facilities by exposing the surface with transient heat loads typically step/impulsive in nature. The surface heating rates are then determined from highly transient temperature history captured by efficient surface temperature sensors. The classical approach is to use thin film gauges (TFGs) in which temperature variations are acquired within milliseconds, thereby allowing calculation of surface heat flux, based on the theory of one-dimensional heat conduction on a semi-infinite body. With recent developments in the soft computing methods, the present study is an attempt for the application of intelligent system technique, called adaptive neuro fuzzy inference system (ANFIS) to recover surface heat fluxes from a given temperature history recorded by TFGs without having the need to solve lengthy analytical equations. Experiments have been carried out by applying known quantity of `impulse heat load' through laser beam on TFGs. The corresponding voltage signals have been acquired and surface heat fluxes are estimated through classical analytical approach. These signals are then used to `train' the ANFIS model, which later predicts output for `test' values. Results from both methods have been compared and these surface heat fluxes are used to predict the non-linear relationship between thermal and electrical properties of the gauges that are exceedingly pertinent to the design of efficient TFGs. Further, surface plots have been created to give an insight about dimensionality effect of the non-linear dependence of thermal/electrical parameters on each other. Later, it is observed that a properly optimized ANFIS model can predict the impulsive heat profiles with significant accuracy. This paper thus shows the

Weld Repair of Thin Aluminum Sheet

Science.gov (United States)

Beuyukian, C. S.; Mitchell, M. J.

1986-01-01

Weld repairing of thin aluminum sheets now possible, using niobium shield and copper heat sinks. Refractory niobium shield protects aluminum adjacent to hole, while copper heat sinks help conduct heat away from repair site. Technique limits tungsten/inert-gas (TIG) welding bombardment zone to melt area, leaving surrounding areas around weld unaffected. Used successfully to repair aluminum cold plates on Space Shuttle, Commercial applications, especially in sealing fractures, dents, and holes in thin aluminum face sheets or clad brazing sheet in cold plates, heat exchangers, coolers, and Solar panels. While particularly suited to thin aluminum sheet, this process also used in thicker aluminum material to prevent surface damage near weld area.

General-purpose heat source: Research and development program, radioisotope thermoelectric generator/thin fragment impact test

International Nuclear Information System (INIS)

Reimus, M.A.H.; Hinckley, J.E.

1996-11-01

The general-purpose heat source provides power for space missions by transmitting the heat of 238 Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system. The results of this test indicated that impact by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel

Influence of heat treatment on field emission characteristics of boron nitride thin films

International Nuclear Information System (INIS)

Li Weiqing; Gu Guangrui; Li Yingai; He Zhi; Feng Wei; Liu Lihua; Zhao Chunhong; Zhao Yongnian

2005-01-01

Boron nitride (BN) nanometer thin films are synthesized on Si (1 0 0) substrates by RF reactive magnetron sputtering. Then the film surfaces are treated in the case of the base pressure below 5 x 10 -4 Pa and the temperature of 800 and 1000 deg. C, respectively. And the films are studied by Fourier transform infrared spectra (FTIR), atomic force microscopic (AFM) and field emission characteristics at different annealing temperature. The results show that the surface heat treatment makes no apparent influence on the surface morphology of the BN films. The transformations of the sample emission characteristics have to do with the surface negative electron affinity (NEA) of the films possibly. The threshold electric fields are lower for BN samples without heat-treating than the treated films, which possibly ascribed to the surface negative electron affinity effect. A threshold field of 8 V/μm and the emission current of 80 μA are obtained. The surface NEA is still presence at the heat treatment temperature of 800 deg. C and disappeared at temperature of 1000 deg. C

Influence of inclined Lorentz force on micropolar fluids in a square cavity with uniform and nonuniform heated thin plate

Energy Technology Data Exchange (ETDEWEB)

Periyadurai, K. [Department of Mathematics, Bharathiar University, Coimbatore 641046, Tamil Nadu (India); Muthtamilselvan, M., E-mail: muthtamill@yahoo.co.in [Department of Mathematics, Bharathiar University, Coimbatore 641046, Tamil Nadu (India); Doh, Deog-Hee [Division of Mechanical Engineering, College of Engineering,Korea Maritime Ocean University, Busan 606781 (Korea, Republic of)

2016-12-15

In the present study, the effect of inclined magnetic field on natural convection of micro-polar fluid in a square cavity with uniform and nonuniform heated thin plate built in centrally is investigated numerically. The vertical walls are cooled while the top and bottom walls are insulated. The thin plate is assumed to be isothermal with a linearly varying temperature. The governing equations were solved by finite volume method using second order central difference scheme and upwind differencing scheme. The numerical investigation is carried out for different governing parameters namely, the Hartmann number, inclination angle of magnetic field, Rayleigh number, vortex viscosity and source non-uniformity parameters. The result shows that the heat transfer rate is decreased when increasing Hartmann number, inclination angle of magnetic field and vortex viscosity parameter. It is found that the non-uniformity parameter affects the fluid flow and temperature distribution especially for the high Rayleigh numbers. Finally, the overall heat transfer rate of micro-polar fluids is found to be smaller than that of Newtonian fluid. - Highlights: • We investigate the effect of inclined magnetic field on micropolar fluid in a cavity. • The effects of uniform and non-uniform heated plate are studied. • The present numerical results are compared with the experimental results. • The addition of vortex viscosity parameter declines the heat transfer performance. • The high heat transfer rate occurs in the vertical plate compared to the horizontal one.

Validation of ANSYS CFX for gas and liquid metal flows with conjugate heat transfer within the European project THINS

Energy Technology Data Exchange (ETDEWEB)

Papukchiev, A., E-mail: angel.papukchiev@grs.de; Buchholz, S.

2017-02-15

Highlights: • ANSYS CFX is validated for gas and liquid metal flows. • L-STAR and TALL-3D experiments are simulated. • Complex flow and heat transfer phenomena are modelled. • Conjugate heat transfer has to be considered in CFD analyses. - Abstract: Within the FP7 European project THINS (Thermal Hydraulics of Innovative Nuclear Systems), numerical tools for the simulation of the thermal-hydraulics of next generation rector systems were developed, applied and validated for innovative coolants. The Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH participated in THINS with activities related to the development and validation of computational fluid dynamics (CFD) and coupled System Thermal Hydraulics (STH) – CFD codes. High quality measurements from the L-STAR and TALL-3D experiments were used to assess the numerical results. Two-equation eddy viscosity and scale resolving turbulence models were used in the validation process of ANSYS CFX for gas and liquid metal flows with conjugate heat transfer. This paper provides a brief overview on the main results achieved at GRS within the project.

Rapid PCR amplification using a microfluidic device with integrated microwave heating and air impingement cooling.

Science.gov (United States)

Shaw, Kirsty J; Docker, Peter T; Yelland, John V; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2010-07-07

A microwave heating system is described for performing polymerase chain reaction (PCR) in a microfluidic device. The heating system, in combination with air impingement cooling, provided rapid thermal cycling with heating and cooling rates of up to 65 degrees C s(-1) and minimal over- or under-shoot (+/-0.1 degrees C) when reaching target temperatures. In addition, once the required temperature was reached it could be maintained with an accuracy of +/-0.1 degrees C. To demonstrate the functionality of the system, PCR was successfully performed for the amplification of the Amelogenin locus using heating rates and quantities an order of magnitude faster and smaller than current commercial instruments.

Half-Space Temperature Field with a Movable Thermally Thin-Coated Boundary Under External Heat Flux

Directory of Open Access Journals (Sweden)

P. A. Vlasov

2014-01-01

Full Text Available In engineering practice analytical methods of the mathematical theory of heat conduction hold a special place. This is due to many reasons, in particular, because of the fact that the solutions of the relevant problems represented in analytically closed form, can be used not only for a parametric analysis of the studied temperature field and to explore the specific features of its formation, but also to test the developed computational algorithms, which are aimed at solving real-world application heat and mass transfer problems. Difficulties arising when using the analytical mathematical theory methods of heat conduction in practice are well known. Also they are significantly exacerbated if the boundaries of the system under study are movable, even in the simplest case, when the law of motion is known.The main goal of the conducted research is to have an analytically closed-form problem solution for finding the orthotropic half-space temperature field, a boundary of which has thermally thin coating exposed to extremely concentrated stationary external heat flux and uniformly moves parallel to itself.The assumption that the covering of the boundary is thermally thin, allowed to realize the idea of \\concentrated capacity", that is to accept the hypothesis that the mean-thickness coating temperature is equal to the temperature of its boundaries. This assumption allowed us to reduce the problem under consideration to a mixed problem for a parabolic equation with a specific boundary condition.The Hankel integral transform of zero order with respect to the radial variable and the Laplace transform with respect to the temporal variable were used to solve the reduced problem. These techniques have allowed us to submit the required solution as an iterated integral.

Effects of Post- Heat Treatment of Nanocrystalline ZnO Thin Films deposited on Zn-Deposited FTO Substrates

Energy Technology Data Exchange (ETDEWEB)

Kim, Ikhyun; Kim, Younggyu; Nam, Giwoong; Leem, Jae-Young [Inje University, Gimhae (Korea, Republic of)

2015-10-15

The effects of heat-treatment temperature on the structural and optical properties of ZnO thin films were investigated with field-effect scanning electron microscopy (SEM), X-ray diffraction analysis, and photoluminescence (PL) measurements. The ZnO thin films were grown on Zn-deposited fluorine-doped tin oxide substrates by sol-gel spin coating. The SEM images of the samples showed that their surfaces had a mountain-chain-like structure. The film annealed at 400 ℃ had the highest degree of alignment along the c-axis, and its residual stress was close to zero. The PL spectra of the ZnO thin films consisted of sharp near-band-edge emissions (NBE) and broad deep-level emissions (DLE) in the visible range. The DLE peaks exhibited a green-to-red shift with an increase in the temperature. The highest INBE/IDLE ratio was observed in the film annealed at 400 ℃. Thus, the optimal temperature for growing high-quality ZnO thin films on Zn-deposited FTO substrates is 400 ℃.

Rapid differentiation of Listeria monocytogenes epidemic clones III and IV and their intact compared with heat-killed populations using Fourier transform infrared spectroscopy and chemometrics.

Science.gov (United States)

Nyarko, Esmond B; Puzey, Kenneth A; Donnelly, Catherine W

2014-06-01

The objectives of this study were to determine if Fourier transform infrared (FT-IR) spectroscopy and multivariate statistical analysis (chemometrics) could be used to rapidly differentiate epidemic clones (ECs) of Listeria monocytogenes, as well as their intact compared with heat-killed populations. FT-IR spectra were collected from dried thin smears on infrared slides prepared from aliquots of 10 μL of each L. monocytogenes ECs (ECIII: J1-101 and R2-499; ECIV: J1-129 and J1-220), and also from intact and heat-killed cell populations of each EC strain using 250 scans at a resolution of 4 cm(-1) in the mid-infrared region in a reflectance mode. Chemometric analysis of spectra involved the application of the multivariate discriminant method for canonical variate analysis (CVA) and linear discriminant analysis (LDA). CVA of the spectra in the wavelength region 4000 to 600 cm(-1) separated the EC strains while LDA resulted in a 100% accurate classification of all spectra in the data set. Further, CVA separated intact and heat-killed cells of each EC strain and there was 100% accuracy in the classification of all spectra when LDA was applied. FT-IR spectral wavenumbers 1650 to 1390 cm(-1) were used to separate heat-killed and intact populations of L. monocytogenes. The FT-IR spectroscopy method allowed discrimination between strains that belong to the same EC. FT-IR is a highly discriminatory and reproducible method that can be used for the rapid subtyping of L. monocytogenes, as well as for the detection of live compared with dead populations of the organism. Fourier transform infrared (FT-IR) spectroscopy and multivariate statistical analysis can be used for L. monocytogenes source tracking and for clinical case isolate comparison during epidemiological investigations since the method is capable of differentiating epidemic clones and it uses a library of well-characterized strains. The FT-IR method is potentially less expensive and more rapid compared to genetic

Local thermodynamic equilibrium in rapidly heated high energy density plasmas

International Nuclear Information System (INIS)

Aslanyan, V.; Tallents, G. J.

2014-01-01

Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance

Development of CuInTe{sub 2} thin film solar cells by electrochemical route with low temperature (80 °C) heat treatment procedure

Energy Technology Data Exchange (ETDEWEB)

Lakhe, Manorama [Electrochemical Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Mahapatra, S.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Chaure, Nandu B., E-mail: n.chaure@physics.unipune.ac.in [Electrochemical Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-02-15

Graphical abstract: Dark and illuminated J–V characteristic for Cell B, successively heat treated at 80 °C for 60 min and corresponding dV/d(J + J{sub L}) versus 1/(J + J{sub L}) plot. Efficiency, η = 3.8%, series resistance, R{sub s} = 43 Ω and ideality factor, n = 1.9 are measured for Cell B. - Highlights: • Temperature, 80 °C is sufficient to produce highly crystalline CuInTe{sub 2} thin films. • Stoichiometric, uniform and well adherent thin films of CuInTe{sub 2} were electrodeposited. • 3.8% efficiency was measured for a cell prepared by successive heat treatment at 80 °C. • ‘R{sub s}’ and ‘n’ investigated for Cell A and B were 47, 43 Ω and 2.0 and 1.9, respectively. - Abstract: The effect of successive low-temperature heat treatment on the properties of electrodeposited CuInTe{sub 2} (CIT) thin films is investigated. The electrodeposition potential, −0.8 V versus Ag/AgCl was optimized by cyclic voltammetry onto CdS coated Fluorine doped tin oxide substrate. The samples were successively heat treated at 80 °C for 5, 30 and 60 min in an air ambient. The structural, morphological, compositional, electrical and optoelectronic properties were studied using XRD, Raman spectroscopy, SEM, FESEM, EDS, Current–Voltage and Capacitance–Voltage measurements. As-prepared CIT film exhibited amorphous nature, whereas the systematic development in the crystallinity was observed in successively heat treated samples. Compact, densely packed, globular surface morphology was observed. The Cu/In ratio was found to be increased systematically from 0.60 to 0.82 with heat treatment duration. The solar cell devices successively heat treated at 80 °C for 30 and 60 min measured an efficiency (η), 3.4% and 3.8%, respectively.

Electromagnetic induction heating for single crystal graphene growth: morphology control by rapid heating and quenching

Science.gov (United States)

Wu, Chaoxing; Li, Fushan; Chen, Wei; Veeramalai, Chandrasekar Perumal; Ooi, Poh Choon; Guo, Tailiang

2015-03-01

The direct observation of single crystal graphene growth and its shape evolution is of fundamental importance to the understanding of graphene growth physicochemical mechanisms and the achievement of wafer-scale single crystalline graphene. Here we demonstrate the controlled formation of single crystal graphene with varying shapes, and directly observe the shape evolution of single crystal graphene by developing a localized-heating and rapid-quenching chemical vapor deposition (CVD) system based on electromagnetic induction heating. Importantly, rational control of circular, hexagonal, and dendritic single crystalline graphene domains can be readily obtained for the first time by changing the growth condition. Systematic studies suggest that the graphene nucleation only occurs during the initial stage, while the domain density is independent of the growth temperatures due to the surface-limiting effect. In addition, the direct observation of graphene domain shape evolution is employed for the identification of competing growth mechanisms including diffusion-limited, attachment-limited, and detachment-limited processes. Our study not only provides a novel method for morphology-controlled graphene synthesis, but also offers fundamental insights into the kinetics of single crystal graphene growth.

Evolution of lateral ordering in symmetric block copolymer thin films upon rapid thermal processing

International Nuclear Information System (INIS)

Ceresoli, Monica; Ferrarese Lupi, Federico; Seguini, Gabriele; Perego, Michele; Sparnacci, Katia; Gianotti, Valentina; Antonioli, Diego; Laus, Michele; Boarino, Luca

2014-01-01

This work reports experimental findings about the evolution of lateral ordering of lamellar microdomains in symmetric PS-b-PMMA thin films on featureless substrates. Phase separation and microdomain evolution are explored in a rather wide range of temperatures (190–340 °C) using a rapid thermal processing (RTP) system. The maximum processing temperature that enables the ordering of block copolymers without introducing any significant degradation of macromolecules is identified. The reported results clearly indicate that the range of accessible temperatures in the processing of these self-assembling materials is mainly limited by the thermal instability of the grafted random copolymer layer, which starts to degrade at T > 300 °C, inducing detachment of the block copolymer thin film. For T ⩽ 290 °C, clear dependence of correlation length (ξ) values on temperature is observed. The highest level of lateral order achievable in the current system in a quasi-equilibrium condition was obtained at the upper processing temperature limit after an annealing time as short as 60 s. (paper)

Performance test of a vertically-directed electric-field cavity resonator made for the rapid gelation apparatus with microwave heating

International Nuclear Information System (INIS)

Yamagishi, Shigeru; Ogawa, Toru; Hasegawa, Atsushi.

1996-06-01

A cavity resonator with vertically-directed electric field was produced and attached to 'the rapid gelation apparatus with microwave heating' previously reported. Using the rapid gelation apparatus, drops of a simulated solution and of U-containing solutions for internal gelation were heated. The results indicated that the heating required for gelation of the U-containing solutions was possible. However, the electric field strength in the cavity resonator at that time was comparable to that causing the discharge due to the gaseous ammonia released from the heated drops. As a result, gel microspheres were not obtained in a stable state. The discussion suggests that the stable gelation would be realized by improving the cavity resonator shape and/or by modifying the power supply accompanied with using a power stabilizer. (author)

Development of laser cladding system to repair wall thinning of 1-inch heat exchanger tube

International Nuclear Information System (INIS)

Terada, Takaya

2013-01-01

We developed a laser cladding system to repair the inner wall wastage of heat exchanger tubes. Our system, which is designed to repair thinning tube walls within 100 mm from the edge of a heat exchanger tube, consists of a fiber laser, a composite-type optical fiberscope, a coupling device, a laser processing head, and a wire-feeding device. All of these components were reconfigured from the technologies of FBR maintenance. The laser processing head, which has a 15-mm outer diameter, was designed to be inserted into a 1-inch heat exchanger tube. We mounted a heatproof broadband mirror for laser cladding and fiberscope observation with visible light inside the laser processing head. The wire-feeding device continuously supplied 0.4-mm wire to the laser irradiation spot with variable feeding speeds from 0.5 to 20 mm/s. We are planning to apply our proposed system to the maintenance of aging industrial plants. (author)

Positioning a thin-wall round wrapper within a heavy wall out-of-round shell of a heat exchanger

International Nuclear Information System (INIS)

Hargrove, H.G.; Thompson, E.G.; Bayless, J.R.

1983-01-01

A thin-wall, generally round wrapper is installed within a heavy wall, rolled heat exchanger shell which has greater out-of-round tolerances than the wrapper and the wrapper is maintained in its round state by utilizing a plurality of jacks disposed adjacent spaced tube support plates within the wrapper. (author)

Baking process of thin plate carbonaceous compact

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Yoshio; Shimada, Toyokazu

1987-06-27

As a production process of a thin plate carbonaceous compact for separator of phosphoric acid fuel cell, there is a process to knead carbonaceous powder and thermosetting resin solution, to form and harden the kneaded material and then to bake, carbonize and graphitize it. However in this baking and carbonization treatment, many thin plate compacts are set in a compiled manner within a heating furnace and receive a heat treatment from their circumference. Since the above compacts to be heated tend generally to be heated from their peripheries, their baked conditions are not homogeneous easily causing the formation of cracks, etc.. As a process to heat and bake homogeneously by removing the above problematical points, this invention offers a process to set in a heating furnace a laminate consisting of the lamination of thin plate carbonaceous compacts and the heat resistant soaking plates which hold the upper and lower ends of the above lamination, to fill the upper and under peripheries of the laminate above with high heat conductive packing material and its side periphery with low heat conductive packing material respectively and to heat and sinter it. In addition, the invention specifies the high and low heat conductive packing materials respectively. (1 fig, 2 tabs)

Hard magnetic properties of rapidly annealed NdFeB thin films on Nb and V buffer layers

International Nuclear Information System (INIS)

Jiang, H.; Evans, J.; O'Shea, M.J.; Du Jianhua

2001-01-01

NdFeB thin films of the form A (20 nm)/NdFeB(d nm)/A(20 nm), where d ranges from 54 to 540 nm and the buffer layer A is Nb or V were prepared on a Si(1 0 0) substrate by magnetron sputtering. The hard Nd 2 Fe 14 B phase is formed by a 30 s rapid anneal or a 20 min anneal. Average crystallite size ranged from 20 to 35 nm with the rapidly annealed samples having the smaller crystallite size. These samples also exhibited a larger coercivity and energy product than those treated by a 20 min vacuum anneal. A maximum coercivity of 26.3 kOe at room temperature was obtained for a Nb/NdFeB (180 nm)/Nb film after a rapid anneal at 725 deg. C. Initial magnetization curves indicate magnetization rotation rather than nucleation of reverse domains is important in the magnetization process. A Brown's equation analysis of the coercivity as a function of temperature allowed us to compare the rapidly annealed and 20 min annealed samples. This analysis suggests that rapid annealing gives higher quality crystalline grains than the 20 min annealed sample leading to the observed large coercivity in the rapidly annealed samples

Rapidly cast crystalline thin sheet materials

International Nuclear Information System (INIS)

Warlimont, H.; Emmerich, K.

1986-01-01

The current state and progress of casting thin sheet and ribbons directly from the melt are reviewed. First, the solidification phenomena pertinent to the process are outlined. Subsequently, Fe-Si,l Fe-Si-Al, Fe-Nd-B, Ag-Cu-Ti, alloy steels, Ni superalloys and Si are treated as examples. Finally, the information available on process development is critically assessed

Electrowetting-based microfluidic operations on rapid-manufactured devices for heat pipe applications

Science.gov (United States)

Hale, Renee S.; Bahadur, Vaibhav

2017-07-01

The heat transport capacity of traditional heat pipes is limited by the capillary pressure generated in the internal wick that pumps condensate to the evaporator. Recently, the authors conceptualized a novel heat pipe architecture, wherein wick-based pumping is replaced by electrowetting (EW)-based pumping of microliter droplets in the adiabatic section. An electrowetting heat pipe (EHP) can overcome the capillary limit to heat transport capacity and enable compact, planar, gravity-insensitive, and ultralow power consumption heat pipes that transport kiloWatt heat loads over extended distances. This work develops a novel technique for rapid, scalable fabrication of EW-based devices and studies critical microfluidic operations underlying the EHP, with the objective of predicting the key performance parameters of the EHP. Devices are fabricated on a printed circuit board (PCB) substrate with mechanically-milled electrodes, and a removable polyimide dielectric film. The first set of experiments uncovers the maximum channel gap (1 mm) for reliable EW-based pumping; this parameter determines the heat transport capacity of the EHP, which scales linearly with the channel gap. The second set of experiments uncovers the maximum channel gap (375 microns) at which EW voltages can successfully split droplets. This is an important consideration which ensures EHP operability in the event of unintentional droplet merging. The third set of experiments demonstrate and study EW-induced droplet generation from an open-to-air reservoir, which mimics the interface between the condenser and adiabatic sections of the EHP. The experimental findings predict that planar, water-based EHPs with a (10 cm by 4 mm) cross section can transport 1.6 kW over extended distances (>1 m), with a thermal resistance of 0.01 K W-1.

Extending the 3ω method: thermal conductivity characterization of thin films.

Science.gov (United States)

Bodenschatz, Nico; Liemert, André; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

2013-08-01

A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3ω approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

Rapid fabrication of mesoporous TiO2 thin films by pulsed fibre laser for dye sensitized solar cells

Science.gov (United States)

Hadi, Aseel; Alhabradi, Mansour; Chen, Qian; Liu, Hong; Guo, Wei; Curioni, Michele; Cernik, Robert; Liu, Zhu

2018-01-01

In this paper we demonstrate for the first time that a fibre laser with a wavelength of 1070 nm and a pulse width of milliseconds can be applied to generate mesoporous nanocrystalline (nc) TiO2 thin films on ITO coated glass in ambient atmosphere, by complete vaporisation of organic binder and inter-connection of TiO2 nanoparticles, without thermally damaging the ITO layer and the glass substrate. The fabrication of the mesoporous TiO2 thin films was achieved by stationary laser beam irradiation of 1 min. The dye sensitized solar cell (DSSC) with the laser-sintered TiO2 photoanode reached higher power conversion efficiency (PCE) of 3.20% for the TiO2 film thickness of 6 μm compared with 2.99% for the furnace-sintered. Electrochemical impedance spectroscopy studies revealed that the laser sintering under the optimised condition effectively decreased charge transfer resistance and increased electron lifetime of the TiO2 thin films. The use of the fibre laser with over 40% wall-plug efficiency offers an economically-feasible, industrial viable solution to the major challenge of rapid fabrication of large scale, mass production of mesoporous metal oxide thin film based solar energy systems, potentially for perovskite and monolithic tandem solar cells, in the future.

Cyclic Solvent Vapor Annealing for Rapid, Robust Vertical Orientation of Features in BCP Thin Films

Science.gov (United States)

Paradiso, Sean; Delaney, Kris; Fredrickson, Glenn

2015-03-01

Methods for reliably controlling block copolymer self assembly have seen much attention over the past decade as new applications for nanostructured thin films emerge in the fields of nanopatterning and lithography. While solvent assisted annealing techniques are established as flexible and simple methods for achieving long range order, solvent annealing alone exhibits a very weak thermodynamic driving force for vertically orienting domains with respect to the free surface. To address the desire for oriented features, we have investigated a cyclic solvent vapor annealing (CSVA) approach that combines the mobility benefits of solvent annealing with selective stress experienced by structures oriented parallel to the free surface as the film is repeatedly swollen with solvent and dried. Using dynamical self-consistent field theory (DSCFT) calculations, we establish the conditions under which the method significantly outperforms both static and cyclic thermal annealing and implicate the orientation selection as a consequence of the swelling/deswelling process. Our results suggest that CSVA may prove to be a potent method for the rapid formation of highly ordered, vertically oriented features in block copolymer thin films.

Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

Energy Technology Data Exchange (ETDEWEB)

Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

2016-06-07

In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods

Directory of Open Access Journals (Sweden)

Kuang-Li Lee

2017-07-01

Full Text Available We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit. The rapid fabrication is also achieved by using radio-frequency (RF sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications.

Energy deposition, heat flow, and rapid solidification during laser and electron beam irradiation of materials

Energy Technology Data Exchange (ETDEWEB)

White, C.W.; Aziz, M.J.

1985-10-01

The fundamentals of energy deposition, heat flow, and rapid solidification during energy deposition from lasers and electron beams is reviewed. Emphasis is placed on the deposition of energy from pulsed sources (10 to 100 ns pulse duration time) in order to achieve high heating and cooling rates (10/sup 8/ to 10/sup 10/ /sup 0/C/s) in the near surface region. The response of both metals and semiconductors to pulsed energy deposition is considered. Guidelines are presented for the choice of energy source, wavelength, and pulse duration time.

Evaporation thermal anslysis of Swallow-tailed Axial-grooved Heat Pipe

Science.gov (United States)

Zhang, Renping

2018-03-01

A detailed mathematical model that describes evaporating characteristics through thin liquid film at the evaporator section of swallow-tailed axial-grooved heat pipe was developed. The numerical simulation results about thin film profile, liquid-vapour interface temperature, evaporating rate and heat flux at the evaporating thin film region were given by the current investigation and the effect of superheat on the liquid-vapour interface temperature, evaporating mass rate and heat flux was discussed. Meanwhile, thermal model of the meniscus region at the evaporating section was developed to calculate the rate of heat transfer. The ratio of the heat conduction in the evaporating thin liquid film region and total heat rate were also discussed. It is indicated that the thickness of thin liquid film rises in a nearly linear fashion. The disjoining pressure can be neglected with increasing the liquid film thickness, tends to be negligibly small. The heat transfer rate at the intrinsic meniscus cannot be compared with that of the evaporating liquid film region.

Temperature of Heating and Cooling of Massive, Thin, and Wedge-Shaped Plates from Hard-to-Machine Steels During Their Grinding

Science.gov (United States)

Dement‧ev, V. B.; Ivanova, T. N.; Dolginov, A. M.

2017-01-01

Grinding of flat parts occurs by solid abrasive particles due to the physicomechanical process of deformation and to the action of a process liquid at high temperatures in a zone small in volume and difficult for observation. The rate of heating and cooling depends on the change in the intensity of the heat flux and in the velocity and time of action of the heat source. A study has been made of the regularities of the influence of each of these parameters on the depth and character of structural transformations during the grinding of flat parts from hard-to-machine steels. A procedure to calculate temperature in grinding massive, thin, and wedge-shaped parts has been developed with account taken of the geometric and thermophysical parameters of the tool and the treated part, and also of cutting regimes. The procedure can be used as a constituent part in developing a system for automatic design of the technological process of grinding of flat surfaces. A relationship between the temperature in the grinding zone and the regimes of treatment has been established which makes it possible to control the quality of the surface layer of massive, thin, and wedge-shaped plates from hard-to-machine steels. The rational boundaries of shift of cutting regimes have been determined.

Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

Science.gov (United States)

Lee, Hyun-Woo; Cho, Won-Ju

2018-01-01

We investigated the effects of vacuum rapid thermal annealing (RTA) on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO) thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs) with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

Rapid heating evaporation of Pb(NO3)2. Evidence for heterogeneous ion-molecule reactions

International Nuclear Information System (INIS)

Radus, T.P.; Udseth, H.R.; Friedman, L.

1979-01-01

A mass spectrometric investigation of the lead nitrate system is reported in which the lead nitrate was evaporated from a probe filament that was heated as rapidly as 5000 0 C/s. Both electron impact (EI) and chemical ionization (CI) source techniques were used in this study. Fragment ions and decomposition products were observed under EI conditions. Under CI conditions solvated fragment ions and protonated solvated molecular ions were detected. Temperature measurements of rates of evaporation were made by monitoring the resistance of the probe filament as it was heated. Activation energies calculated by using these temperature coefficients of evaporation rates indicate that evaporations under CI conditions are assisted by heterogeneous ion-molecule reactions

Development and Demonstration of a High Efficiency, Rapid Heating, Low NOx Alternative to Conventional Heating of Round Steel Shapes, Steel Substrate (Strip) and Coil Box Transfer Bars

Energy Technology Data Exchange (ETDEWEB)

Kurek, Harry; Wagner, John

2010-01-25

Direct Flame Impingement involves the use of an array of very high-velocity flame jets impinging on a work piece to rapidly heat the work piece. The predominant mode of heat transfer is convection. Because of the locally high rate of heat transfer at the surface of the work piece, the refractory walls and exhaust gases of a DFI furnace are significantly cooler than in conventional radiant heating furnaces, resulting in high thermal efficiency and low NOx emissions. A DFI furnace is composed of a successive arrangement of heating modules through or by which the work piece is conveyed, and can be configured for square, round, flat, and curved metal shapes (e.g., billets, tubes, flat bars, and coiled bars) in single- or multi-stranded applications.

Effect of Heat and Laser Treatment on Cu2S Thin Film Sprayed on Polyimide Substrate

Science.gov (United States)

Magdy, Wafaa; Mahmoud, Fawzy A.; Nassar, Amira H.

2018-02-01

Three samples of copper sulfide Cu2S thin film were deposited on polyimide substrate by spray pyrolysis using deposition temperature of 400°C and deposition time of about 45 min. One of the samples was left as deposited, another was heat treated, while the third was laser treated. The structural, surface morphological, optical, mechanical, and electrical properties of the films were investigated. X-ray diffraction (XRD) analysis showed that the copper sulfide films were close to copper-rich phase (Cu2S). Increased crystallite size after heat and laser treatment was confirmed by XRD analysis and scanning electron microscopy. Vickers hardness measurements showed that the samples' hardness values were enhanced with increasing crystallite size, representing an inverse Hall-Petch (H-P) effect. The calculated optical bandgap of the treated films was lower than that of the deposited film. Finally, it was found that both heat and laser treatment enhanced the physical properties of the sprayed Cu2S films on polyimide substrate for use in solar energy applications.

Thin-Layer Solutions of the Helmholtz and Related Equations

KAUST Repository

Ockendon, J. R.

2012-01-01

This paper concerns a certain class of two-dimensional solutions to four generic partial differential equations-the Helmholtz, modified Helmholtz, and convection-diffusion equations, and the heat conduction equation in the frequency domain-and the connections between these equations for this particular class of solutions.S pecifically, we consider thin-layer solutions, valid in narrow regions across which there is rapid variation, in the singularly perturbed limit as the coefficient of the Laplacian tends to zero.F or the wellstudied Helmholtz equation, this is the high-frequency limit and the solutions in question underpin the conventional ray theory/WKB approach in that they provide descriptions valid in some of the regions where these classical techniques fail.E xamples are caustics, shadow boundaries, whispering gallery, and creeping waves and focusing and bouncing ball modes.It transpires that virtually all such thin-layer models reduce to a class of generalized parabolic wave equations, of which the heat conduction equation is a special case. Moreover, in most situations, we will find that the appropriate parabolic wave equation solutions can be derived as limits of exact solutions of the Helmholtz equation.W e also show how reasonably well-understood thin-layer phenomena associated with any one of the four generic equations may translate into less well-known effects associated with the others.In addition, our considerations also shed some light on the relationship between the methods of matched asymptotic, WKB, and multiple-scales expansions. © 2012 Society for Industrial and Applied Mathematics.

Modeling and Analysis of Entropy Generation in Light Heating of Nanoscaled Silicon and Germanium Thin Films

Directory of Open Access Journals (Sweden)

José Ernesto Nájera-Carpio

2015-07-01

Full Text Available In this work, the irreversible processes in light heating of Silicon (Si and Germanium (Ge thin films are examined. Each film is exposed to light irradiation with radiative and convective boundary conditions. Heat, electron and hole transport and generation-recombination processes of electron-hole pairs are studied in terms of a phenomenological model obtained from basic principles of irreversible thermodynamics. We present an analysis of the contributions to the entropy production in the stationary state due to the dissipative effects associated with electron and hole transport, generation-recombination of electron-hole pairs as well as heat transport. The most significant contribution to the entropy production comes from the interaction of light with the medium in both Si and Ge. This interaction includes two processes, namely, the generation of electron-hole pairs and the transferring of energy from the absorbed light to the lattice. In Si the following contribution in magnitude comes from the heat transport. In Ge all the remaining contributions to entropy production have nearly the same order of magnitude. The results are compared and explained addressing the differences in the magnitude of the thermodynamic forces, Onsager’s coefficients and transport properties of Si and Ge.

Molecular dynamics study on the effect of boundary heating rate on the phase change characteristics of thin film liquid

Energy Technology Data Exchange (ETDEWEB)

Hasan, Mohammad Nasim, E-mail: nasim@me.buet.ac.bd.com; Morshed, A. K. M. Monjur, E-mail: shavik@me.buet.ac.bd.com; Rabbi, Kazi Fazle, E-mail: rabbi35.me10@gmail.com; Haque, Mominul, E-mail: mominulmarup@gmail.com [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 (Bangladesh)

2016-07-12

In this study, theoretical investigation of thin film liquid phase change phenomena under different boundary heating rates has been conducted with the help of molecular dynamics simulation. To do this, the case of argon boiling over a platinum surface has been considered. The study has been conducted to get a better understanding of the nano-scale physics of evaporation/boiling for a three phase system with particular emphasis on the effect of boundary heating rate. The simulation domain consisted of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system was brought to an equilibrium state at 90 K with the help of equilibrium molecular dynamics and then the temperature of the bottom wall was increased to a higher temperature (250 K/130 K) over a finite heating period. Depending on the heating period, the boundary heating rate has been varied in the range of 1600×10{sup 9} K/s to 8×10{sup 9} K/s. The variations of argon region temperature, pressure, net evaporation number with respect to time under different boundary heating rates have been determined and discussed. The heat fluxes normal to platinum wall for different cases were also calculated and compared with theoretical upper limit of maximum possible heat transfer to elucidate the effect of boundary heating rate.

Micro-architecture embedding ultra-thin interlayer to bond diamond and silicon via direct fusion

Science.gov (United States)

Kim, Jong Cheol; Kim, Jongsik; Xin, Yan; Lee, Jinhyung; Kim, Young-Gyun; Subhash, Ghatu; Singh, Rajiv K.; Arjunan, Arul C.; Lee, Haigun

2018-05-01

The continuous demand on miniaturized electronic circuits bearing high power density illuminates the need to modify the silicon-on-insulator-based chip architecture. This is because of the low thermal conductivity of the few hundred nanometer-thick insulator present between the silicon substrate and active layers. The thick insulator is notorious for releasing the heat generated from the active layers during the operation of devices, leading to degradation in their performance and thus reducing their lifetime. To avoid the heat accumulation, we propose a method to fabricate the silicon-on-diamond (SOD) microstructure featured by an exceptionally thin silicon oxycarbide interlayer (˜3 nm). While exploiting the diamond as an insulator, we employ spark plasma sintering to render the silicon directly fused to the diamond. Notably, this process can manufacture the SOD microarchitecture via a simple/rapid way and incorporates the ultra-thin interlayer for minute thermal resistance. The method invented herein expects to minimize the thermal interfacial resistance of the devices and is thus deemed as a breakthrough appealing to the current chip industry.

Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

Directory of Open Access Journals (Sweden)

Hyun-Woo Lee

2018-01-01

Full Text Available We investigated the effects of vacuum rapid thermal annealing (RTA on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

Rapid further heating of tokamak plasma by fast-rising magnetic pulse

International Nuclear Information System (INIS)

Inoue, N.; Nihei, H.; Yamazaki, K.; Ichimura, M.; Morikawa, J.; Hoshino, K.; Uchida, T.

1977-01-01

The object of the experiment was to study the rapid further heating of a tokamak plasma and its influence on confinement. For this purpose, a high-voltage theta-pinch pulse was applied to a tokamak plasma and production of a high-temperature (keV) plasma was ensured within a microsecond. The magnetic pulse is applied at the plasma current maximum parallel or antiparallel to the study toroidal field. In either case, the pulsed field quickly penetrates the plasma and the plasma resistivity estimated from the penetration time is about 100 times larger than the classical. A burst of energetic neutrals of approximately 1 μs duration was observed and the energy distribution had two components of the order of 1 keV and 0.1 keV in the antiparallel case. Doppler broadening measurement shows heating of ions to a temperature higher than 200 eV; however, the line profile is not always Maxwellian distribution. The X-rays disappear at the moment of applying the magnetic pulse and reappear about 100 μs later with an intensive burst, while both energy levels are the same (approximately 100 keV). (author)

A new method for fabrication of thin plates and thin-walled cylinder made of fiber reinforced metal (FRM) and its application for the rotating drum of the nuclear fuel centrifugal separator

International Nuclear Information System (INIS)

Okamura, Tatsuya

1978-01-01

The composite materials using resins as the base materials show the defect that the characteristics deteriorate rapidly at elevated temperature. Therefore the FRMs using relatively ductile metals as the base materials combined with reinforcing fibers have been considered. The result of study on the combination of base materials and fibers and the manufacturing method is rarely reported in Japan. In FRMs, direct contact of fibers mutually must be avoided, especially making nodes lowers the strength extremely. The fibers must be long monofilaments of 0.1 to 0.2 mm diameter. High precision wire winding machines are required for making uniform FRMs. For the diffusion joining of preformed materials, in which fibers are put in order on metallic foils, pressure and heat are applied. The author succeeded to develop the technique for making thin-walled cylinders of FRMs, including the method of winding brittle filaments and the method of pressurizing and heating based on the difference of thermal expansion of dies. The mechanical properties of thin plates and thin-walled cylinders made of monofilaments of B, SiC and SUS and aluminum alloy foils were obtained, and rotation test of the cylinders was carried out. It was clarified that the FRMs of B-Al and SiC-Al groups are very excellent materials, and most suitable for the rotary drums of super-high speed centrifuges. (Kako, I.)

Investigation of the unidirectional spin heat conveyer effect in a 200 nm thin Yttrium Iron Garnet film

Science.gov (United States)

Wid, Olga; Bauer, Jan; Müller, Alexander; Breitenstein, Otwin; Parkin, Stuart S. P.; Schmidt, Georg

2016-06-01

We have investigated the unidirectional spin wave heat conveyer effect in sub-micron thick yttrium iron garnet (YIG) films using lock-in thermography (LIT). Although the effect is small in thin layers this technique allows us to observe asymmetric heat transport by magnons which leads to asymmetric temperature profiles differing by several mK on both sides of the exciting antenna, respectively. Comparison of Damon-Eshbach and backward volume modes shows that the unidirectional heat flow is indeed due to non-reciprocal spin-waves. Because of the finite linewidth, small asymmetries can still be observed when only the uniform mode of ferromagnetic resonance is excited. The latter is of extreme importance for example when measuring the inverse spin-Hall effect because the temperature differences can result in thermovoltages at the contacts. Because of the non-reciprocity these thermovoltages reverse their sign with a reversal of the magnetic field which is typically deemed the signature of the inverse spin-Hall voltage.

A thin-walled pressurized sphere exposed to external general corrosion and nonuniform heating

Science.gov (United States)

Sedova, Olga S.; Pronina, Yulia G.; Kuchin, Nikolai L.

2018-05-01

A thin-walled spherical shell subjected to simultaneous action of internal and external pressure, nonuniform heating and outside mechanochemical corrosion is considered. It is assumed that the shell is homogeneous, isotropic and linearly elastic. The rate of corrosion is linearly dependent on the equivalent stress, which is the sum of mechanical and temperature stress components. Paper presents a new analytical solution, which takes into account the effect of the internal and external pressure values themselves, not only their difference. At the same time, the new solution has a rather simple form as compared to the results based on the solution to the Lame problem for a thick-walled sphere under pressure. The solution obtained can serve as a benchmark for numerical analysis and for a qualitative forecast of durability of the vessel.

Development of a rapid thermal annealing process for polycrystalline silicon thin-film solar cells on glass

Energy Technology Data Exchange (ETDEWEB)

Rau, B. [Helmholtz Centre Berlin for Materials and Energy, Kekulestr. 5, D-12489 Berlin (Germany)], E-mail: bjoern.rau@helmholtz-berlin.de; Weber, T.; Gorka, B.; Dogan, P.; Fenske, F.; Lee, K.Y.; Gall, S.; Rech, B. [Helmholtz Centre Berlin for Materials and Energy, Kekulestr. 5, D-12489 Berlin (Germany)

2009-03-15

In this report, we discuss the influence of rapid thermal annealing (RTA) on the performance of polycrystalline Si (poly-Si) thin-film solar cells on glass where the poly-Si layers are differently prepared. The first part presents a comprehensive study of RTA treatments on poly-Si thin-films made by solid phase crystallization (SPC) (standard material of CSG Solar AG, Thalheim). By varying both plateau temperature (up to 1050 deg. C) and duration (up to 1000 s) of the annealing profile, we determined the parameters for a maximum open-circuit voltage (V{sub OC}). In addition, we applied our standard plasma hydrogenation treatment in order to passivate the remaining intra-grain defects and grain boundaries by atomic hydrogen resulting in a further increase of V{sub OC}. We found, that the preceding RTA treatment increases the effect of hydrogenation already at comparable low RTA temperatures. The effect on hydrogenation increases significantly with RTA temperature. In a second step we investigated the effect of the RTA and hydrogenation on large-grained poly-Si films based on the epitaxial thickening of poly-Si seed layers.

Thinning and rupture of a thin liquid film on a heated surface

Energy Technology Data Exchange (ETDEWEB)

Bankoff, S.G.; Davis, S.H.

1992-08-05

Results on the dynamics and stability of thin films are summarized on the following topics: forced dryout, film instabilities on a horizontal plane and on inclined planes, instrumentation, coating flows, and droplet spreading. (DLC)

Thin-film solar cells

International Nuclear Information System (INIS)

Aberle, Armin G.

2009-01-01

The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

The influence of wavelength-dependent radiation in simulation of lamp-heated rapid thermal processing systems

Energy Technology Data Exchange (ETDEWEB)

Ting, A. [Sandia National Labs., Livermore, CA (United States). Computational Mechanics Dept.

1994-08-01

Understanding the thermal response of lamp-heated rapid thermal processing (RTP) systems requires understanding relatively complex radiation exchange among opaque and partially transmitting surfaces and materials. The objective of this paper is to investigate the influence of wavelength-dependent radiative properties. The examples used for the analysis consider axisymmetric systems of the kind that were developed by Texas Instruments (TI) for the Microelectronics Manufacturing Science and Technology (MMST) Program and illustrate a number of wavelength-dependent (spectral) effects. The models execute quickly on workstation class computing flatforms, and thus permit rapid comparison of alternative reactor designs and physical models. The fast execution may also permit the incorporation of these models into real-time model-based process control algorithms.

Thin Film Photovoltaic/Thermal Solar Panels

Institute of Scientific and Technical Information of China (English)

David JOHNSTON

2008-01-01

A solar panel is described.in which thin films of semiconductor are deposited onto a metal substrate.The semiconductor-metal combination forms a thin film photovoltaic cell,and also acts as a reflector,absorber tandem, which acts as a solar selective surface,thus enhancing the solar thermal performance of the collector plate.The use of thin films reduces the distance heat is required to flow from the absorbing surface to the metal plate and heat exchange conduits.Computer modelling demonstrated that,by suitable choice of materials,photovohaic efficiency call be maintained,with thermal performance slishtly reduced,compared to that for thermal-only panels.By grading the absorber layer-to reduce the band gap in the lower region-the thermal performance can be improved,approaching that for a thermal-only solar panel.

Numerical analysis of natural convection and radiation heat transfer from various shaped thin fin-arrays placed on a horizontal plate-a conjugate analysis

International Nuclear Information System (INIS)

Dogan, M.; Sivrioglu, Mecit; Yılmaz, Onder

2014-01-01

Highlights: • Optimum fin shape is determined for natural convection and radiation heat transfer. • Fin array with the optimum shape has a much greater average heat transfer coefficient. • The most important factors affecting the heat transfer coefficient are determined. - Abstract: Steady state natural convection and radiation heat transfer from various shaped thin fin-arrays on a horizontal base plate has been numerically investigated. A conjugate analysis has been carried out in which the conservation equations of mass, momentum and energy for the fluid in the two fin enclosure are solved together with the heat conduction equation in the fin and the base plate. Heat transfer by radiation is also considered in analysis. The heat transfer coefficient has been determined for each of the fin array considered in the present study at the same base and the same total area. The results of the analysis show that there are some important geometrical factors affecting the design of fin arrays. Taking into consideration these factors, an optimum fin shape that yields the highest average heat transfer coefficient has been determined

Blast-Wave Generation and Propagation in Rapidly Heated Laser-Irradiated Targets

Science.gov (United States)

Ivancic, S. T.; Stillman, C. R.; Nilson, P. M.; Solodov, A. A.; Froula, D. H.

2017-10-01

Time-resolved extreme ultraviolet (XUV) spectroscopy was used to study the creation and propagation of a >100-Mbar blast wave in a target irradiated by an intense (>1018WWcm2 cm2) laser pulse. Blast waves provide a platform to generate immense pressures in the laboratory. A temporal double flash of XUV radiation was observed when viewing the rear side of the target, which is attributed to the emergence of a blast wave following rapid heating by a fast-electron beam generated from the laser pulse. The time-history of XUV emission in the photon energy range of 50 to 200 eV was recorded with an x-ray streak camera with 7-ps temporal resolution. The heating and expansion of the target was simulated with an electron transport code coupled to 1-D radiation-hydrodynamics simulations. The temporal delay between the two flashes measured in a systematic study of target thickness and composition was found to evolve in good agreement with a Sedov-Taylor blast-wave solution. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and Department of Energy Office of Science Award Number DE-SC-0012317.

Bounds on heat transport in rapidly rotating Rayleigh–Bénard convection

International Nuclear Information System (INIS)

Grooms, Ian; Whitehead, Jared P

2015-01-01

The heat transport in rotating Rayleigh–Bénard convection is considered in the limit of rapid rotation (small Ekman number E) and strong thermal forcing (large Rayleigh number Ra). The analysis proceeds from a set of asymptotically reduced equations appropriate for rotationally constrained dynamics; the conjectured range of validity for these equations is Ra ≲ E −8/5 . A rigorous bound on heat transport of Nu ⩽ 20.56Ra 3 E 4 is derived in the limit of infinite Prandtl number using the background method. We demonstrate that the exponent in this bound cannot be improved on using a piece-wise monotonic background temperature profile like the one used here. This is true for finite Prandtl numbers as well, i.e. Nu ≲ Ra 3 is the best upper bound for this particular setup of the background method. The feature that obstructs the availability of a better bound in this case is the appearance of small-scale thermal plumes emanating from (or entering) the thermal boundary layer. The derived upper bound is consistent with, although significantly higher than the observed behaviour in simulations of the reduced equations, which find at most Nu ∼ Ra 2 E 8/3 . (paper)

In situ transmission electron microscopy investigation of the interfacial reaction between Ni and Al during rapid heating in a nanocalorimeter

Energy Technology Data Exchange (ETDEWEB)

Grapes, Michael D., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Material Measurement Laboratory, Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Lawrence Livermore National Laboratory, Materials Science and Technology Division, Livermore, California 94550 (United States); Woll, Karsten [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Institute of Applied Materials, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); LaVan, David A., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Material Measurement Laboratory, Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2014-11-01

The Al/Ni formation reaction is highly exothermic and of both scientific and technological significance. In this report, we study the evolution of intermetallic phases in this reaction at a heating rate of 830 K/s. 100-nm-thick Al/Ni bilayers were deposited onto nanocalorimeter sensors that enable the measurement of temperature and heat flow during rapid heating. Time-resolved transmission electron diffraction patterns captured simultaneously with thermal measurements allow us to identify the intermetallic phases present and reconstruct the phase transformation sequence as a function of time and temperature. The results show a mostly unaltered phase transformation sequence compared to lower heating rates.

Frequency-dependent heat capacity

DEFF Research Database (Denmark)

Behrens, Claus Flensted

The frequency–dependent heat capacity of super-cooled glycerol near the glass transition is measured using the 3w detection technique. An electrical conducting thin film with a temperature–dependent electrical resistance is deposited on a substrate. The thin film is used simultaneously as a heater...

Analysis of Hydrodynamics and Heat Transfer in a Thin Liquid Film Flowing over a Rotating Disk by Integral Method

Science.gov (United States)

Basu, S.; Cetegen, B. M.

2005-01-01

An integral analysis of hydrodynamics and heat transfer in a thin liquid film flowing over a rotating disk surface is presented for both constant temperature and constant heat flux boundary conditions. The model is found to capture the correct trends of the liquid film thickness variation over the disk surface and compare reasonably well with experimental results over the range of Reynolds and Rossby numbers covering both inertia and rotation dominated regimes. Nusselt number variation over the disk surface shows two types of behavior. At low rotation rates, the Nusselt number exhibits a radial decay with Nusselt number magnitudes increasing with higher inlet Reynolds number for both constant wall temperature and heat flux cases. At high rotation rates, the Nusselt number profiles exhibit a peak whose location advances radially outward with increasing film Reynolds number or inertia. The results also compare favorably with the full numerical simulation results from an earlier study as well as with the reported experimental results.

Rutile TiO{sub 2} active-channel thin-film transistor using rapid thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung-Jin; Heo, Kwan-Jun; Yoo, Su-Chang; Choi, Seong-Gon [Chungbuk National University, Cheongju (Korea, Republic of); Chang, Seung-Wook [Samsung Display, Co., Ltd., Suwon (Korea, Republic of)

2014-10-15

TiO{sub 2} active-channel thin-film transistors (TFTs), in which the bottom-gate top-contact architecture was prepared with atomic layer deposition grown TiO{sub 2} as the semiconducting layer, were fabricated and then investigated based on key process parameters, such as the rapid thermal annealing (RTA) temperature. Structural analyses suggested that TiO{sub 2} films annealed at temperatures above 500 .deg. C changed from an amorphous to a rutile phase. The TFT with a TiO{sub 2} semiconductor annealed at 600 .deg. C exhibited strongly-saturated output characteristics, a much higher on/off current ratio of 4.3 x 10{sup 5}, and an electron mobility of 0.014 cm{sup 2}/Vs. Moreover, the potential for manipulating TiO{sub 2}-based TFTs with RTA methodology was demonstrated through the realization of a simple resistive-load inverter.

Investigation of modified thin SnO2 layers treated by rapid thermal annealing by means of hollow cathode spectroscopy and AFM technique

International Nuclear Information System (INIS)

Djulgerova, R; Popova, L; Beshkov, G; Petrovic, Z Lju; Rakocevic, Z; Mihailov, V; Gencheva, V; Dohnalik, T

2006-01-01

By means of hollow cathode spectroscopy and atomic force microscopy the surface morphology and composition of SnO 2 thin film, modified with hexamethyldisilazane after rapid thermal annealing treatment (800-1200 deg. C), are investigated. Formation of crystalline structure is suggested at lower temperatures. Depolimerization, destruction and dehydration are developed at temperatures of 1200 deg. C. It is shown that the rapid thermal annealing treatment could modify both the surface morphology and the composition of the layer, thus changing the adsorption ability of the sensing layer. The results confirm the ability of hollow cathode emission spectroscopy for depth profiling of new materials especially combined with standard techniques

Laser short-pulse heating of an aluminum thin film: Energy transfer in electron and lattice sub-systems

Energy Technology Data Exchange (ETDEWEB)

Bin Mansoor, Saad; Sami Yilbas, Bekir, E-mail: bsyilbas@kfupm.edu.sa

2015-08-15

Laser short-pulse heating of an aluminum thin film is considered and energy transfer in the film is formulated using the Boltzmann equation. Since the heating duration is short and the film thickness is considerably small, thermal separation of electron and lattice sub-systems is incorporated in the analysis. The electron–phonon coupling is used to formulate thermal communication of both sub-systems during the heating period. Equivalent equilibrium temperature is introduced to account for the average energy of all phonons around a local point when they redistribute adiabatically to an equilibrium state. Temperature predictions of the Boltzmann equation are compared with those obtained from the two-equation model. It is found that temperature predictions from the Boltzmann equation differ slightly from the two-equation model results. Temporal variation of equivalent equilibrium temperature does not follow the laser pulse intensity in the electron sub-system. The time occurrence of the peak equivalent equilibrium temperature differs for electron and lattice sub-systems, which is attributed to phonon scattering in the irradiated field in the lattice sub-system. In this case, time shift is observed for occurrence of the peak temperature in the lattice sub-system.

Laser short-pulse heating of an aluminum thin film: Energy transfer in electron and lattice sub-systems

International Nuclear Information System (INIS)

Bin Mansoor, Saad; Sami Yilbas, Bekir

2015-01-01

Laser short-pulse heating of an aluminum thin film is considered and energy transfer in the film is formulated using the Boltzmann equation. Since the heating duration is short and the film thickness is considerably small, thermal separation of electron and lattice sub-systems is incorporated in the analysis. The electron–phonon coupling is used to formulate thermal communication of both sub-systems during the heating period. Equivalent equilibrium temperature is introduced to account for the average energy of all phonons around a local point when they redistribute adiabatically to an equilibrium state. Temperature predictions of the Boltzmann equation are compared with those obtained from the two-equation model. It is found that temperature predictions from the Boltzmann equation differ slightly from the two-equation model results. Temporal variation of equivalent equilibrium temperature does not follow the laser pulse intensity in the electron sub-system. The time occurrence of the peak equivalent equilibrium temperature differs for electron and lattice sub-systems, which is attributed to phonon scattering in the irradiated field in the lattice sub-system. In this case, time shift is observed for occurrence of the peak temperature in the lattice sub-system

Particulates reduction in laser-ablated YBa2Cu3O7-δ thin films by laser-induced plume heating

International Nuclear Information System (INIS)

Koren, G.; Baseman, R.J.; Gupta, A.; Lutwyche, M.I.; Laibowitz, R.B.

1990-01-01

Experimental demonstration of reduction in the number and size of particulates formed in the laser ablation deposition of YBa 2 Cu 3 O 7-δ thin films is obtained by the use of a second laser which further heats and fragments the blowoff material in the plume formed by the first laser. This results in a smoother film with higher critical current density as compared to that obtained without the second laser irradiation of the plume

Theoretical investigation of the thermodynamic properties of metallic thin films

International Nuclear Information System (INIS)

Hung, Vu Van; Phuong, Duong Dai; Hoa, Nguyen Thi; Hieu, Ho Khac

2015-01-01

The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks

Theoretical investigation of the thermodynamic properties of metallic thin films

Energy Technology Data Exchange (ETDEWEB)

Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)

2015-05-29

The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.

Thermoluminescence fast neutron dosimetry by laser heating

International Nuclear Information System (INIS)

Mathur, V.K.; Brown, M.D.; Braeunlich, P.

1984-01-01

Heating rates in excess of 10 4 K.sec -1 have been achieved for thin layers of TL dosemeters by laser heating. The high heating rate improves the signal to noise ratio up to a factor of 10 3 . Thus sensitive thin film fast neutron dosemeters with negligible self-shielding have become a practical reality. Thin samples of CaSO 4 :Dy have been investigated for their response to fast neutrons from a Pu-Be source and a 14.6 MeV neutron generator by using a hydrogenous radiator. A 15 watt CO 2 laser was focussed on the thin TLD layer to a spot size of less than 1 mm to heat it. An exposure of a few tens of milliseconds was sufficient to obtain a TLD curve, which was displayed and processed by a wave form digitiser. The laser spot could be scanned over the TLD sample by a x-y positioner and a large number of observations were obtained on each sample. Preliminary results show that it is possible to obtain a figure of merit of approx. 5% in a mixed n, γ field. A practical design for a fast neutron dosemeter is proposed. (author)

Rapid amplification/detection of nucleic acid targets utilizing a HDA/thin film biosensor.

Science.gov (United States)

Jenison, Robert; Jaeckel, Heidi; Klonoski, Joshua; Latorra, David; Wiens, Jacinta

2014-08-07

Thin film biosensors exploit a flat, optically coated silicon-based surface whereupon formation of nucleic acid hybrids are enzymatically transduced in a molecular thin film that can be detected by the unaided human eye under white light. While the limit of sensitivity for detection of nucleic acid targets is at sub-attomole levels (60 000 copies) many clinical specimens containing bacterial pathogens have much lower levels of analyte present. Herein, we describe a platform, termed HDA/thin film biosensor, which performs helicase-dependant nucleic acid amplification on a thin film biosensor surface to improve the limit of sensitivity to 10 copies of the mecA gene present in methicillin-resistant strains of Staphylococcus. As double-stranded DNA is unwound by helicase it was either bound by solution-phase DNA primers to be copied by DNA polymerase or hybridized to surface immobilized probe on the thin film biosensor surface to be detected. Herein, we show that amplification reactions on the thin film biosensor are equivalent to in standard thin wall tubes, with detection at the limit of sensitivity of the assay occurring after 30 minutes of incubation time. Further we validate the approach by detecting the presence of the mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) from positive blood culture aliquots with high specificity (signal/noise ratio of 105).

Numerical study of heat and mass transfer during evaporation of a thin liquid film

Directory of Open Access Journals (Sweden)

Oubella M’hand

2015-01-01

Full Text Available A numerical study of mixed convection heat and mass transfer with film evaporation in a vertical channel is developed. The emphasis is focused on the effects of vaporization of three different liquid films having widely different properties, along the isothermal and wetted walls on the heat and mass transfer rates in the channel. The induced laminar downward flow is a mixture of blowing dry air and vapour of water, methanol or acetone, assumed as ideal gases. A two-dimensional steady state and elliptical flow model, connected with variable thermo-physical properties, is used and the phase change problem is based on thin liquid film assumptions. The governing equations of the model are solved by a finite volume method and the velocity-pressure fields are linked by SIMPLE algorithm. The numerical results, including the velocity, temperature and concentration profiles, as well as axial variations of Nusselt numbers, Sherwood number and dimensionless film evaporation rate are presented for two values of inlet temperature and Reynolds number. It was found that lower the inlet temperature and Re, the higher the induced flows cooling with respect of most volatile film. The better mass transfer rates related with film evaporation are found for a system with low mass diffusion coefficient.

Thin-film calorimetry. In-situ characterization of materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Omelcenko, Alexander; Wulfmeier, Hendrik; Albrecht, Daniel; Fritze, Holger [Clausthal Univ. of Technology, Goslar (Germany). Inst. of Energy Research and Physical Technologies; El Mofid, Wassima; Ivanov, Svetlozar; Bund, Andreas [Ilmenau Univ. of Technology (Germany). Dept. of Electrochemistry

2017-11-15

Thin-film calorimetry allows for qualitative and quantitative in-situ analysis of thermodynamic properties of thin films and thin-film systems from room temperature up to 1000 C. It is based on highly sensitive piezoelectric langasite resonators which serve simultaneously as planar temperature sensors and substrates for the films of interest. Generation or consumption of heat during phase transformations of the films cause deviations from the regular course of the resonance frequency. Thermodynamic data such as phase transformation temperatures and enthalpies are extracted from these deviations. Thin-film calorimetry on Sn and Al thin films is performed to prove the concept. The results demonstrate high reproducibility of the measurement approach and are in agreement with literature data obtained by established calorimetric techniques. The calibration of the system is done in different atmospheres by application of defined heat pulses via heating structures. The latter replace the films of interest and simulate phase transformations to provide detailed analysis of the heat transfer mechanisms occurring in the measurement system. Based on this analysis, a data evaluation concept is developed. Application-relevant studies are performed on thin films of the lithium-ion battery materials NMC(A), NCA, LMO, and MoS{sub 2}. Their phase transformation temperatures and enthalpies are evaluated in oxidizing and reducing atmospheres. Furthermore, their thermodynamic stability ranges are presented. Finally, measurements on all-solid-state thin-film batteries during electrochemical cycling are performed. They demonstrate the suitability of the system for in-situ investigations.

Mechanical Testing of PMCs under Simulated Rapid Heat-Up Propulsion Environments. II; In-Plane Compressive Behavior

Science.gov (United States)

Stokes, Eric H.; Shin, E. Eugene; Sutter, James K.

2003-01-01

Carbon fiber thermoset polymer matrix composites (PMC) with high temperature polyimide based in-situ polymerized monomer reactant (PMR) resin has been used for some time in applications which can see temperatures up to 550 F. Currently, graphite fiber PMR based composites are used in several aircraft engine components including the outer bypass duct for the GE F-404, exit flaps for the P&W F-100-229, and the core cowl for the GE/Snecma CF6-80A3. Newer formulations, including PMR-II-50 are being investigated as potential weight reduction replacements of various metallic components in next generation high performance propulsion rocket engines that can see temperatures which exceed 550 F. Extensive FEM thermal modeling indicates that these components are exposed to rapid heat-up rates (up to -200 F/sec) and to a maximum temperature of around 600 F. Even though the predicted maximum part temperatures were within the capability of PW-II-50, the rapid heat-up causes significant through-thickness thermal gradients in the composite part and even more unstable states when combined with moisture. Designing composite parts for such extreme service environments will require accurate measurement of intrinsic and transient mechanical properties and the hygrothermal performance of these materials under more realistic use conditions. The mechanical properties of polymers degrade when exposed to elevated temperatures even in the absence of gaseous oxygen. Accurate mechanical characterization of the material is necessary in order to reduce system weight while providing sufficient factors of safety. Historically, the testing of PMCs at elevated temperatures has been plagued by the antagonism between two factors. First, moisture has been shown to profoundly affect the mechanical response of these materials at temperatures above their glass transition temperature while concurrently lowering the material's Tg. Moisture phenomena is due to one or a combination of three effects, i

Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

Science.gov (United States)

Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

2015-02-01

Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

Electrospun fibrous thin film microextraction coupled with desorption corona beam ionization-mass spectrometry for rapid analysis of antidepressants in human plasma.

Science.gov (United States)

Chen, Di; Hu, Yu-Ning; Hussain, Dilshad; Zhu, Gang-Tian; Huang, Yun-Qing; Feng, Yu-Qi

2016-05-15

Appropriate sample preparations prior to analysis can significantly enhance the sensitivity of ambient ionization techniques, especially during the enrichment or purification of analytes in the presence of complex biological matrix. Here in, we developed a rapid analysis method by the combination of thin film microextraction (TFME) and desorption corona beam ionization (DCBI) for the determination of antidepressants in human plasma. Thin films used for extraction consisted of sub-micron sized highly ordered mesoporous silica-carbon composite fibers (OMSCFs), simply prepared by electrospinning and subsequent carbonization. Typically, OMSCFs thin film was immersed into the diluted plasma for extraction of target analytes and then directly subjected to the DCBI-MS for detection. Size-exclusion effect of mesopores contributed to avoid of the protein precipitation step prior to extraction. Mass transfer was benefited from high surface-to-volume ratio which is attributed to macroporous network and ordered mesostructures. Moreover, the OMSCFs provided mixed-mode hydrophobic/ion-exchange interactions towards target analytes. Thus, the detection sensitivity was greatly improved due to effective enrichment of the target analytes and elimination of matrix interferences. After optimization of several parameters related to extraction performance, the proposed method was eventually applied for the determination of three antidepressants in human plasma. The calibration curves were plotted in the range of 5-1000 ng/mL with acceptable linearity (R(2) >0.983). The limits of detection (S/N=3) of three antidepressants were in ranges of 0.3-1 ng/mL. Reproducibility was achieved with RSD less than 17.6% and the relative recoveries were in ranges of 83.6-116.9%. Taken together, TFME-DCBI-MS method offers a powerful capacity for rapid analysis to achieve much-improved sensitivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface plasmon resonance assisted rapid laser joining of glass

Energy Technology Data Exchange (ETDEWEB)

Zolotovskaya, Svetlana A.; Tang, Guang; Abdolvand, Amin, E-mail: a.abdolvand@dundee.ac.uk [School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, Zengbo [School of Electronic Engineering, Bangor University, Bangor LL57 1UT (United Kingdom)

2014-08-25

Rapid and strong joining of clear glass to glass containing randomly distributed embedded spherical silver nanoparticles upon nanosecond pulsed laser irradiation (∼40 ns and repetition rate of 100 kHz) at 532 nm is demonstrated. The embedded silver nanoparticles were ∼30–40 nm in diameter, contained in a thin surface layer of ∼10 μm. A joint strength of 12.5 MPa was achieved for a laser fluence of only ∼0.13 J/cm{sup 2} and scanning speed of 10 mm/s. The bonding mechanism is discussed in terms of absorption of the laser energy by nanoparticles and the transfer of the accumulated localised heat to the surrounding glass leading to the local melting and formation of a strong bond. The presented technique is scalable and overcomes a number of serious challenges for a widespread adoption of laser-assisted rapid joining of glass substrates, enabling applications in the manufacture of microelectronic devices, sensors, micro-fluidic, and medical devices.

Temperature studies of optical parameters of (Ag3AsS3)0.6(As2S3)0.4 thin films prepared by rapid thermal evaporation and pulse laser deposition

Science.gov (United States)

Studenyak, I. P.; Kutsyk, M. M.; Buchuk, M. Yu.; Rati, Y. Y.; Neimet, Yu. Yu.; Izai, V. Yu.; Kökényesi, S.; Nemec, P.

2016-02-01

(Ag3AsS3)0.6(As2S3)0.4 thin films were deposited using rapid thermal evaporation (RTE) and pulse laser deposition (PLD) techniques. Ag-enriched micrometre-sized cones (RTE) and bubbles (PLD) were observed on the thin film surface. Optical transmission spectra of the thin films were studied in the temperature range 77-300 K. The Urbach behaviour of the optical absorption edge in the thin films due to strong electron-phonon interaction was observed, the main parameters of the Urbach absorption edge were determined. Temperature dependences of the energy position of the exponential absorption edge and the Urbach energy are well described in the Einstein model. Dispersion and temperature dependences of refractive indices were analysed; a non-linear increase of the refractive indices with temperature was revealed. Disordering processes in the thin films were studied and compared with bulk composites, the differences between the thin films prepared by RTE and PLD were analysed.

Parametric study of thin film evaporation from nanoporous membranes

Science.gov (United States)

Wilke, Kyle L.; Barabadi, Banafsheh; Lu, Zhengmao; Zhang, TieJun; Wang, Evelyn N.

2017-10-01

The performance and lifetime of advanced electronics are often dictated by the ability to dissipate heat generated within the device. Thin film evaporation from nanoporous membranes is a promising thermal management approach, which reduces the thermal transport distance across the liquid film while also providing passive capillary pumping of liquid to the evaporating interface. In this work, we investigated the dependence of thin film evaporation from nanoporous membranes on a variety of geometric parameters. Anodic aluminum oxide membranes were used as experimental templates, where pore radii of 28-75 nm, porosities of 0.1-0.35, and meniscus locations down to 1 μm within the pore were tested. We demonstrated different heat transfer regimes and observed more than an order of magnitude increase in dissipated heat flux by operating in the pore-level evaporation regime. The pore diameter had little effect on pore-level evaporation performance due to the negligible conduction resistance from the pore wall to the evaporating interface. The dissipated heat flux scaled with porosity as the evaporative area increased. Furthermore, moving the meniscus as little as 1 μm into the pore decreased the dissipated heat flux by more than a factor of two due to the added resistance to vapor escaping the pore. The experimental results elucidate thin film evaporation from nanopores and confirm findings of recent modeling efforts. This work also provides guidance for the design of future thin film evaporation devices for advanced thermal management. Furthermore, evaporation from nanopores is relevant to water purification, chemical separations, microfluidics, and natural processes such as transpiration.

Characterization of Alq3 thin films by a near-field microwave microprobe.

Science.gov (United States)

Hovsepyan, Artur; Lee, Huneung; Sargsyan, Tigran; Melikyan, Harutyun; Yoon, Youngwoon; Babajanyan, Arsen; Friedman, Barry; Lee, Kiejin

2008-09-01

We observed tris-8-hydroxyquinoline aluminum (Alq3) thin films dependence on substrate heating temperatures by using a near-field microwave microprobe (NFMM) and by optical absorption at wavelengths between 200 and 900 nm. The changes of absorption intensity at different substrate heating temperatures are correlated to the changes in the sheet resistance of Alq3 thin films.

Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation.

Science.gov (United States)

Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao

2016-09-07

The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

Oscillating heat pipes

CERN Document Server

Ma, Hongbin

2015-01-01

This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

Study of instantaneous unsteady heat transfer in a rapid compression-expansion machine using zero dimensional k- ε turbulence model

International Nuclear Information System (INIS)

Bakhshan, Y.; Karim, G. A.; Mansouri, S. H.

2003-01-01

In this investigation, the instantaneous unsteady heat transfer within a pneumatically driven rapid compression-expansion machine that offers simple, well-controlled and known boundary conditions was studied. Values of the instantaneous apparent overall heat flux from the cylinder gas to the wall surfaces were calculated using a thermodynamics analysis of the experimentally measured pressure and volume temporal development. Corresponding heat flux values were also calculated through the application of a zero-dimensional k- ε turbulence model the characteristic velocity is a contribution of turbulence kinetic energy, mean kinetic energy of charged air into cylinder and piston motion for the calculation of Reynolds, Nusselt and Prandtl numbers. Comparison of the zero-dimensional k- ε turbulence model prediction with experimental data shows good agreement for all compression ratios

Rapidly curable electrically conductive clear coatings

Energy Technology Data Exchange (ETDEWEB)

Bowman, Mark P.; Anderson, Lawrence G.; Post, Gordon L.

2018-01-16

Rapidly curable electrically conductive clear coatings are applied to substrates. The electrically conductive clear coating includes to clear layer having a resinous binder with ultrafine non-stoichiometric tungsten oxide particles dispersed therein. The clear coating may be rapidly cured by subjecting the coating to infrared radiation that heats the tungsten oxide particles and surrounding resinous binder. Localized heating increases the temperature of the coating to thereby thermally cure the coating, while avoiding unwanted heating of the underlying substrate.

Thulium-170 heat source

Science.gov (United States)

Walter, Carl E.; Van Konynenburg, Richard; VanSant, James H.

1992-01-01

An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

Fast Adaptive Thermal Camouflage Based on Flexible VO₂/Graphene/CNT Thin Films.

Science.gov (United States)

Xiao, Lin; Ma, He; Liu, Junku; Zhao, Wei; Jia, Yi; Zhao, Qiang; Liu, Kai; Wu, Yang; Wei, Yang; Fan, Shoushan; Jiang, Kaili

2015-12-09

Adaptive camouflage in thermal imaging, a form of cloaking technology capable of blending naturally into the surrounding environment, has been a great challenge in the past decades. Emissivity engineering for thermal camouflage is regarded as a more promising way compared to merely temperature controlling that has to dissipate a large amount of excessive heat. However, practical devices with an active modulation of emissivity have yet to be well explored. In this letter we demonstrate an active cloaking device capable of efficient thermal radiance control, which consists of a vanadium dioxide (VO2) layer, with a negative differential thermal emissivity, coated on a graphene/carbon nanotube (CNT) thin film. A slight joule heating drastically changes the emissivity of the device, achieving rapid switchable thermal camouflage with a low power consumption and excellent reliability. It is believed that this device will find wide applications not only in artificial systems for infrared camouflage or cloaking but also in energy-saving smart windows and thermo-optical modulators.

Furnace for rapid thermal processing

NARCIS (Netherlands)

Roozeboom, F.; Duine, P.A.; Sluis, P. van der

2001-01-01

A Method (1) for Rapid Thermal Processing of a wafer (7), wherein the wafer (7) is heated by lamps (9), and the heat radiation is reflected by an optical switching device (15,17) which is in the reflecting state during the heating stage. During the cooling stage of the wafer (7), the heat is

Rapid dynamic thinning on Upernavik Icestream, West Greenland

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

2011-01-01

The main outlet glaciers in Greenland have more than doubled their contribution to global sea level rise over the last decade. Several studies have shown increase in ice discharge from the main outlet glaciers (notably Kangerdlugssuaq (KG) and Helheim glaciers (HG) in Southeast Greenland, and Jak......) laser altimetry data supplemented with altimeter surveys from NASA’s Airborne Topographic Mapper (ATM). To assess thinning prior to 2003, we analyze 1985 aerial photos and derived a 2x2 m grid digital elevation model (DEM)....

Simplified and rapid method for extraction of ergosterol from natural samples and detection with quantitative and semi-quantitative methods using thin-layer chromatography

OpenAIRE

Larsen, Cand.scient Thomas; Ravn, Senior scientist Helle; Axelsen, Senior Scientist Jørgen

2004-01-01

A new and simplified method for extraction of ergosterol (ergoste-5,7,22-trien-3-beta-ol) from fungi in soil and litter was developed using pre-soaking extraction and paraffin oil for recovery. Recoveries of ergosterol were in the range of 94 - 100% depending on the solvent to oil ratio. Extraction efficiencies equal to heat-assisted extraction treatments were obtained with pre-soaked extraction. Ergosterol was detected with thin-layer chromatography (TLC) using fluorodensitometry with a quan...

Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

2005-11-21

A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops.

Large Area Thin Film Silicon: Synergy between Displays and Solar Cells

NARCIS (Netherlands)

Schropp, R.E.I.

2012-01-01

Thin-film silicon technology has changed our society, owing to the rapid advance of its two major application fields in communication (thin-film displays) and sustainable energy (thin-film solar cells). Throughout its development, advances in these application fields have always benefitted each

Thermoelectric prospects of chemically deposited PbSe and SnSe thin films

Science.gov (United States)

Nair, P. K.; Martínez, Ana Karen; Rosa García Angelmo, Ana; Barrios Salgado, Enue; Nair, M. T. S.

2018-03-01

Thin films of PbSe of 400-600 nm in thickness, were obtained via chemical deposition from a solution containing lead nitrate, thiourea and selenosufate. SnSe thin films of 90-180 nm in thickness, were also obtained by chemical deposition from a solution containing selenosulfate. Optical and electrical properties of these thin films were significantly altered by heating them in selenium vapor at 300 °C. Thin film PbSe has a bandgap (Eg) of 1.17 eV (direct gap, forbidden transitions), which decreases to 0.77 eV when it has been heated. Its electrical conductivity (σ) is p-type: 0.18 Ω-1 cm-1 (as-prepared), and 6.4 Ω-1 cm-1 when heated. Thin film SnSe is of orthorhombic crystalline structure which remains stable when heated at 300 °C, but its Eg increases from 1.12 eV (indirect) in as-prepared film to 1.5 eV (direct, forbidden transitions) upon heating. Its electrical conductivity is p-type, which increases from 0.3 Ω-1 cm-1 (as-prepared) to 1 Ω-1 cm-1 when heated (without Se-vapor). When SnSe film is heated at 300 °C in the presence of Se-vapor, they transform to SnSe2, with Eg of 1.5 eV (direct, forbidden) with n-type electrical conductivity, 11 Ω-1 cm-1. The Seebeck coefficient for the PbSe films is: +0.55 mV K-1 (as prepared) and +0.275 mV K-1 (heated); for SnSe films it is: +0.3 mV K-1 (as prepared) and +0.20 mV K-1 (heated); and for SnSe2 film, - 0.35 mV K-1. A five-element PbSe-SnSe2-PbSe-SnSe2-PbSe thermoelectric device demonstrated 50 mV for a temperature difference ΔT = 20 °C (2.5 mV K-1). For SnSe-SnSe2-SnSe-SnSe2-SnSe device, the value is 15 mV for ΔT = 20 °C (0.75 mV K-1). Prospect of these thin films in thermoelectric devices of hybrid materials, in which the coatings may be applied on distinct substrate and geometries is attractive.

Inkjet printable nanosilver suspensions for enhanced sintering quality in rapid manufacturing

International Nuclear Information System (INIS)

Bai, John G; Creehan, Kevin D; Kuhn, Howard A

2007-01-01

Inkjet printable nanosilver suspensions were prepared by dispersing 30 nm silver particles into a water-based binder system to enhance the sintering quality in rapid manufacturing. During three-dimensional printing (3DP), the nanosilver suspensions were inkjet printed onto repetitively spread microsilver powder for selective joining. Since the nanosilver particles in the suspensions can be sintered at relatively low temperatures to bond the neighbouring microsilver powder, they were used to provide the continuous bonding strength of the manufacturing parts during the heat-up procedure of the sintering operation. Comparative study shows that the silver parts printed using the nanosilver suspension were significantly enhanced in sintering quality than those printed using the binder system, especially when the silver parts had thin or small features with high aspect ratios

Simple gun for vapor deposition of organic thin films

International Nuclear Information System (INIS)

Sato, N.; Seki, K.; Inokuchi, H.

1987-01-01

A simple evaporation gun for preparing organic thin films was fabricated using commercially available parts of an electron gun for a TV Braun tube. The device permits sample heating to be easily controlled because of the small heat capacity

Rapid preparation method for technetium-99m bicisate

Energy Technology Data Exchange (ETDEWEB)

Hung, J.C. [Nuclear Medicine, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota (United States); Chowdhury, S. [Nuclear Medicine, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota (United States); Redfern, M.G. [Nuclear Medicine, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota (United States); Mahoney, D.W. [Section of Biostatistics, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota (United States)

1997-06-10

The method currently recommended for the preparation of technetium-99m bicisate ({sup 99m}Tc-bicisate) requires a lengthy 30-min incubation at room temperature. The purpose of this study was to evaluate an alternative method to shorten the preparation time. {sup 99m}Tc-bicisate was prepared with 3.7 GBq (100 mCi) {sup 99m}Tc according to the manufacturer`s instructions, except for the final incubation step, which was replaced with the microwave heating procedure. A standard thin-layer chromatography (TLC) method (i.e., Baker-Flex silica gel IB-F TLC plate with ethyl acetate as mobile phase) was used for the determination of the radiochemical purity (RCP) of {sup 99m}Tc-bicisate. Our evaluation with different microwave heating processes (300 W with different heating times) demonstrated that as the microwave heating temperature was increased (i.e., 44 -71 C), an increased percentage of samples reached 95% within 5 min post preparation (n=58). The highest RCP value (i.e., 97.4%{+-}0.5%, n=10) could be obtained immediately after an 8-s microwave heating time at 300 W (microwave temperature at 69 C), and an average RCP value of 96.4%{+-}1.3% (n=90) was maintained throughout the 24-h evaluation period. However, the trend seemed to reverse at higher microwave temperatures (i.e., 76 -90 C), which reconfirmed our initial findings that overheating had no benefit for the preparation of {sup 99m}Tc-bicisate. To ensure that temperature was the only determining factor, a hot water incubator set at 69 C was used (n=6). Similar RCP results were achieved. In conclusion, the use of a microwave oven at a low heat cycle provides a rapid and efficient way to prepare {sup 99m}Tc-bicisate. (orig.). With 3 figs., 1 tab.

Simulation of heat pipe rapid transient performance using a multi-nodal implicit finite difference scheme

International Nuclear Information System (INIS)

Peery, J.S.; Best, F.R.

1987-01-01

A model to simulate heat pipe rapid transients has been developed. This model uses a one-dimensional development of the continuity and momentum equations to solve for the velocity and pressure distributions in both the liquid and vapor regions. A two-dimensional development of the energy equation is used to determine the temperature distributions in the liquid and vapor regions, as well as in the walls of the heat pipe. The vapor and liquid regions are coupled through mass and energy transfer due to evaporation and condensation. The model used for this phenomenon is based on the physical conditions of the vapor and liquid for a given node. However, this model for evaporation and condensation not only causes the energy equation to be nonlinear but also constrains the time step to 10 -4 seconds for convergence to be reached. The model has been run for small transients up to 2 seconds to produce temperature distributions and demonstrate the convergence difficulties associated with the evaporation/condensation model used

Loop-Mediated Isothermal Amplification Using a Lab-on-a-Disc Device with Thin-film Phase Change Material.

Science.gov (United States)

Ko, Junguk; Yoo, Jae-Chern

2018-03-05

The design and fabrication of temperature measurement systems that facilitate successful realization of DNA amplification using a lab-on-a-disc (LOD) device are a highly challenging task. The major challenge lies in the fact that such a system must be directly attached to a heating chamber in a way that enables the accurate measurement of temperature of the chamber while allowing the LOD to rotate. This paper presents a temperature control system for implementing isothermal amplification of DNA samples using an LOD device. The proposed system utilizes a thin-film phase change material and non-contact heating system to remotely measure the actual temperature of the chamber and, if required, rapidly heat it to the desired temperature. The results of the experiments performed in this study demonstrate that the proposed system provides an automated platform for molecular amplification and exhibits an operational performance comparable to that of traditional microcentrifuge tube-based isothermal amplification systems.

Shape memory characteristics of sputter-deposited Ti-Ni thin films

International Nuclear Information System (INIS)

Miyazaki, Shuichi; Ishida, Akira.

1994-01-01

Ti-Ni shape memory alloy thin films were deposited using an RF magnetron sputtering apparatus. The as-sputtered films were heat-treated in order to crystallize and memorize. After the heat treatment, the shape memory characteristics have been investigated using DSC and thermomechanical tests. Upon cooling the thin films, the solution-treated films showed a single peak in the DSC curve indicating a single stage transformation occurring from B2 to the martensitic phase, while the age-treated films showed double peaks indicating a two-stage transformation, i.e., from B2 to the R-phase, then to the martensitic phase. A perfect shape memory effect was achieved in these sputter-deposited Ti-Ni thin films in association both with the R-phase and martensitic transformations. Transformation temperatures increased linearly with increasing applied stress. The transformation strain also increased with increasing stress. The shape memory characteristics were strongly affected by heat-treatment conditions. (author)

Status of Joining Thin Sheet and Thin Wall Tubes of 14YWT

Energy Technology Data Exchange (ETDEWEB)

Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-09-18

Beginning this fiscal year, the FCRD research project initiated an investigation on joining thin sections of the advanced ODS 14YWT ferritic alloy. Friction stir welding (FSW) was investigated as a method to join thin plate and tubing of 14YWT since it is a solid state joining method that has been shown in past studies to be a promising method for joining plates of ODS alloys, such as 14YWT. However, this study will attempt to be the first to demonstrate if FSW can successfully join thin plates and thin wall tubing of 14YWT. In the first FSW attempt, a 1.06 cm thick plate of 14YWT (SM13 heat) was successfully rolled at 1000ºC to the target thickness of 0.1 cm with no edge cracking. This achievement is a highlight since previous attempts to roll 14YWT plates have resulted in extensive cracking. For the FSW run, a pin tool being developed by the ORNL FSW Process Development effort was used. The first FSW run successfully produced a bead-on-plate weld in the 0.1 cm thick plate. The quality of the weld zone appears very good with no evidence of large defects such as cavities. The microstructural characterization study of the bead-on-plate weld zone has been initiated to compare the results of the microstructure analysis with those obtained in the reference microstructural analysis of the 14YWT (SM13 heat) that showed ultra-fine grain size of 0.43 μm and a high number density of ~2-5 nm sizes oxygen-enriched nanoclusters.

Modeling microscale heat transfer using Calore.

Energy Technology Data Exchange (ETDEWEB)

Gallis, Michail A.; Rader, Daniel John; Wong, Chung-Nin Channy; Bainbridge, Bruce L.; Torczynski, John Robert; Piekos, Edward Stanley

2005-09-01

Modeling microscale heat transfer with the computational-heat-transfer code Calore is discussed. Microscale heat transfer problems differ from their macroscopic counterparts in that conductive heat transfer in both solid and gaseous materials may have important noncontinuum effects. In a solid material, three noncontinuum effects are considered: ballistic transport of phonons across a thin film, scattering of phonons from surface roughness at a gas-solid interface, and scattering of phonons from grain boundaries within the solid material. These processes are modeled for polycrystalline silicon, and the thermal-conductivity values predicted by these models are compared to experimental data. In a gaseous material, two noncontinuum effects are considered: ballistic transport of gas molecules across a thin gap and accommodation of gas molecules to solid conditions when reflecting from a solid surface. These processes are modeled for arbitrary gases by allowing the gas and solid temperatures across a gas-solid interface to differ: a finite heat transfer coefficient (contact conductance) is imposed at the gas-solid interface so that the temperature difference is proportional to the normal heat flux. In this approach, the behavior of gas in the bulk is not changed from behavior observed under macroscopic conditions. These models are implemented in Calore as user subroutines. The user subroutines reside within Sandia's Source Forge server, where they undergo version control and regression testing and are available to analysts needing these capabilities. A Calore simulation is presented that exercises these models for a heated microbeam separated from an ambient-temperature substrate by a thin gas-filled gap. Failure to use the noncontinuum heat transfer models for the solid and the gas causes the maximum temperature of the microbeam to be significantly underpredicted.

Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

International Nuclear Information System (INIS)

Gandy, J.H.; Pruden, E.L.; Cox, F.R.

1983-01-01

Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units

Rapid NMR method for the quantification of organic compounds in thin stillage.

Science.gov (United States)

Ratanapariyanuch, Kornsulee; Shen, Jianheng; Jia, Yunhua; Tyler, Robert T; Shim, Youn Young; Reaney, Martin J T

2011-10-12

Thin stillage contains organic and inorganic compounds, some of which may be valuable fermentation coproducts. This study describes a thorough analysis of the major solutes present in thin stillage as revealed by NMR and HPLC. The concentration of charged and neutral organic compounds in thin stillage was determined by excitation sculpting NMR methods (double pulse field gradient spin echo). Compounds identified by NMR included isopropanol, ethanol, lactic acid, 1,3-propanediol, acetic acid, succinic acid, glycerophosphorylcholine, betaine, glycerol, and 2-phenylethanol. The concentrations of lactic and acetic acid determined with NMR were comparable to those determined using HPLC. HPLC and NMR were complementary, as more compounds were identified using both methods. NMR analysis revealed that stillage contained the nitrogenous organic compounds betaine and glycerophosphorylcholine, which contributed as much as 24% of the nitrogen present in the stillage. These compounds were not observed by HPLC analysis.

Multi-step cure kinetic model of ultra-thin glass fiber epoxy prepreg exhibiting both autocatalytic and diffusion-controlled regimes under isothermal and dynamic-heating conditions

Science.gov (United States)

Kim, Ye Chan; Min, Hyunsung; Hong, Sungyong; Wang, Mei; Sun, Hanna; Park, In-Kyung; Choi, Hyouk Ryeol; Koo, Ja Choon; Moon, Hyungpil; Kim, Kwang J.; Suhr, Jonghwan; Nam, Jae-Do

2017-08-01

As packaging technologies are demanded that reduce the assembly area of substrate, thin composite laminate substrates require the utmost high performance in such material properties as the coefficient of thermal expansion (CTE), and stiffness. Accordingly, thermosetting resin systems, which consist of multiple fillers, monomers and/or catalysts in thermoset-based glass fiber prepregs, are extremely complicated and closely associated with rheological properties, which depend on the temperature cycles for cure. For the process control of these complex systems, it is usually required to obtain a reliable kinetic model that could be used for the complex thermal cycles, which usually includes both the isothermal and dynamic-heating segments. In this study, an ultra-thin prepreg with highly loaded silica beads and glass fibers in the epoxy/amine resin system was investigated as a model system by isothermal/dynamic heating experiments. The maximum degree of cure was obtained as a function of temperature. The curing kinetics of the model prepreg system exhibited a multi-step reaction and a limited conversion as a function of isothermal curing temperatures, which are often observed in epoxy cure system because of the rate-determining diffusion of polymer chain growth. The modified kinetic equation accurately described the isothermal behavior and the beginning of the dynamic-heating behavior by integrating the obtained maximum degree of cure into the kinetic model development.

Effect of oxygen partial pressure on texture development in lead zirconate titanate thin films processed from metalorganic precursors

International Nuclear Information System (INIS)

Norton, Jarrod L.; Liedl, Gerald L.; Slamovich, Elliott B.

1999-01-01

Metalorganic liquid precursors were used to examine the effects of processing atmosphere on texture development in oriented Pb(Zr 0.60 Ti 0.40 )O 3 thin films. After removal of organic ligands via pyrolysis, the films were heated at 25 degree sign C/min in a 5% H 2 /Ar atmosphere until a switching temperature, after which the atmosphere was switched to pure oxygen. The films were heated to a maximum temperature of 650 degree sign C with switching temperatures ranging from 450 to 600 degree sign C. The degree of (111) orientation in the lead zirconate titanate (PZT) films increased with increasing switching temperature, resulting in highly textured (111) PZT films. These results suggest that atmosphere control plays a significant role in texture development during rapid thermal processing. (c) 1999 Materials Research Society

Preparation and characterization of nanocrystalline porous TiO2/WO3 composite thin films

International Nuclear Information System (INIS)

Hsu, C.-S.; Lin, C.-K.; Chan, C.-C.; Chang, C.-C.; Tsay, C.-Y.

2006-01-01

TiO 2 materials possessing not only photocatalytic but also electrochromic properties have attracted many research and development interests. Though WO 3 exhibits excellent electrochromic properties, the much higher cost and water-sensitivity of WO 3 as compared with the TiO 2 may restrict the practical application of WO 3 materials. In the present study, the feasibility of preparing nanocrystalline porous TiO 2 /WO 3 composite thin films was investigated. Precursors of sols TiO 2 and/or WO 3 and polystyrene microspheres were used to prepare nanocrystalline pure TiO 2 , WO 3 , and composite TiO 2 /WO 3 thin films by spin coating. The spin-coated thin films were amorphous and, after heat treating at a temperature of 500 o C, nanocrystalline TiO 2 , TiO 2 /WO 3 , and WO 3 thin films with or without pores were prepared successfully. The heat-treated thin films were colorless and coloration-bleaching phenomena can be observed during cyclic voltammetry tests. The heat-treated thin films exhibited good reversible electrochromic behavior while the porous TiO 2 /WO 3 composite film exhibited improved electrochromic properties

Residual stresses estimation in tubes after rapid heating of surface

International Nuclear Information System (INIS)

Serikov, S.V.

1992-01-01

Results are presented on estimation of residual stresses in tubes of steel types ShKh15, EhP836 and 12KIMF after heating by burning pyrotechnic substance inside tubes. External tube surface was heated up to 400-450 deg C under such treatment. Axial stresses distribution over tube wall thickness was determined for initial state, after routine heat treatment and after heating with the use of fireworks. Inner surface heating was shown to essentially decrease axial stresses in tubes

Discovery of Rapid and Reversible Water Insertion in Rare Earth Sulfates: A New Process for Thermochemical Heat Storage.

Science.gov (United States)

Hatada, Naoyuki; Shizume, Kunihiko; Uda, Tetsuya

2017-07-01

Thermal energy storage based on chemical reactions is a prospective technology for the reduction of fossil-fuel consumption by storing and using waste heat. For widespread application, a critical challenge is to identify appropriate reversible reactions that occur below 250 °C, where abundant low-grade waste heat and solar energy might be available. Here, it is shown that lanthanum sulfate monohydrate La 2 (SO 4 ) 3 ⋅H 2 O undergoes rapid and reversible dehydration/hydration reactions in the temperature range from 50 to 250 °C upon heating/cooling with remarkably small thermal hysteresis (water is removed from, or inserted in La 2 (SO 4 ) 3 ⋅H 2 O with progressive change in hydration number x without phase change. It is also revealed that only a specific structural modification of La 2 (SO 4 ) 3 exhibits this reversible dehydration/hydration behavior. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electro-thermo-mechanical coupling analysis of deep drawing with resistance heating for aluminum matrix composites sheet

Science.gov (United States)

Zhang, Kaifeng; Zhang, Tuoda; Wang, Bo

2013-05-01

Recently, electro-plastic forming to be a focus of attention in materials hot processing research area, because it is a sort of energy-saving, high efficient and green manufacturing technology. An electro-thermo-mechanical model can be adopted to carry out the sequence simulation of aluminum matrix composites sheet deep drawing via electro-thermal coupling and thermal-mechanical coupling method. The first step of process is resistance heating of sheet, then turn off the power, and the second step is deep drawing. Temperature distribution of SiCp/2024Al composite sheet by resistance heating and sheet deep drawing deformation were analyzed. During the simulation, effect of contact resistances, temperature coefficient of resistance for electrode material and SiCp/2024Al composite on temperature distribution were integrally considered. The simulation results demonstrate that Sicp/2024Al composite sheet can be rapidly heated to 400° in 30s using resistances heating and the sheet temperature can be controlled by adjusting the current density. Physical properties of the electrode materials can significantly affect the composite sheet temperature distribution. The temperature difference between the center and the side of the sheet is proportional to the thermal conductivity of the electrode, the principal cause of which is that the heat transfers from the sheet to the electrode. SiCp/2024Al thin-wall part can be intactly manufactured at strain rate of 0.08s-1 and the sheet thickness thinning rate is limited within 20%, which corresponds well to the experimental result.

Laser heated solenoid as a neutron source facility

International Nuclear Information System (INIS)

Steinhauer, L.C.; Rose, P.H.

1975-01-01

Conceptual designs are presented for a radiation test facility based on a laser heated plasma confined in a straight solenoid. The thin plasma column, a few meters in length and less than a centimeter in diameter, serves as a line source of neutrons. Test samples are located within or just behind the plasma tube, at a radius of 1-2 cm from the axis. The plasma is heated by an axially-directed powerful long-wavelength laser beam. The plasma is confined radially in the intense magnetic field supplied by a pulsed solenoid surrounding the plasma tube. The facility is pulsed many times a second to achieve a high time-averaged neutron flux on the test samples. Based on component performance achievable in the near term (e.g., magnetic field, laser pulse energy) and assuming classical physical processes, it appears that average fluxes of 10 13 to 10 14 neutrons/cm 2 -sec can be achieved in such a device. The most severe technical problems in such a facility appear to be rapid pulsing design and lifetime of some electrical and laser components

Heat-pipe Earth.

Science.gov (United States)

Moore, William B; Webb, A Alexander G

2013-09-26

The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

Energy Technology Data Exchange (ETDEWEB)

Jahangir, S.; Cheng, Xuan; Huang, H. H.; Nagarajan, V. [School of Materials Science and Engineering, University of New South Wales, Sydney 2052 (Australia); Ihlefeld, J. [Electronic, Optical, and Nanomaterials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2014-10-28

Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO{sub 2}/(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

International Nuclear Information System (INIS)

Jahangir, S.; Cheng, Xuan; Huang, H. H.; Nagarajan, V.; Ihlefeld, J.

2014-01-01

Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO 2 /(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

Causes and consequences of mid–21st-century rapid ice loss events simulated by the Rossby centre regional atmosphere-ocean model

Directory of Open Access Journals (Sweden)

Jean-Philippe Paquin

2013-08-01

Full Text Available Recent observations and modelling studies suggest that the Arctic climate is undergoing important transition. One manifestation of this change is seen in the rapid sea-ice cover decrease as experienced in 2007 and 2012. Although most numerical climate models cannot adequately reproduce the recent changes, some models produce similar Rapid Ice Loss Events (RILEs during the mid–21st-century. This study presents an analysis of four specific RILEs clustered around 2040 in three transient climate projections performed with the coupled Rossby Centre regional Atmosphere-Ocean model (RCAO. The analysis shows that long-term thinning causes increased vulnerability of the Arctic Ocean sea-ice cover. In the Atlantic sector, pre-conditioning (thinning of sea ice combined with anomalous atmospheric and oceanic heat transport causes large ice loss, while in the Pacific sector of the Arctic Ocean sea-ice albedo feedback appears important, particularly along the retreating sea-ice margin. Although maximum sea-ice loss occurs in the autumn, response in surface air temperature occurs in early winter, caused by strong increase in ocean-atmosphere surface energy fluxes, mainly the turbulent fluxes. Synchronicity of the events around 2040 in the projections is caused by a strong large-scale atmospheric circulation anomaly at the Atlantic lateral boundary of the regional model. The limited impact on land is caused by vertical propagation of the surface heat anomaly rather than horizontal, caused by the absence of low-level temperature inversion over the ocean.

Heat Flux Instrumentation Laboratory (HFIL)

Data.gov (United States)

Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

Electrochromic properties of nanocrystalline MoO3 thin films

International Nuclear Information System (INIS)

Hsu, C.-S.; Chan, C.-C.; Huang, H.-T.; Peng, C.-H.; Hsu, W.-C.

2008-01-01

Electrochromic MoO 3 thin films were prepared by a sol-gel spin-coating technique. The spin-coated films were initially amorphous; they were calcined, producing nanocrystalline MoO 3 thin films. The effects of annealing temperatures ranging from 100 o C to 500 o C were investigated. The electrochemical and electrochromic properties of the films were measured by cyclic voltammetry and by in-situ optical transmittance techniques in 1 M LiClO 4 /propylene carbonate electrolyte. Experimental results showed that the transmittance of MoO 3 thin films heat-treated at 350 o C varied from 80% to 35% at λ = 550 nm (ΔT = ∼ 45%) and from 86% to 21% at λ ≥ 700 nm (ΔT = ∼ 65%) after coloration. Films heat-treated at 350 deg. C exhibited the best electrochromic properties in the present study

Heating patterns during cancer heat therapy as a function of blood flow

International Nuclear Information System (INIS)

Mendecki, J.; Friedenthal, E.; Botstein, C.; Sterzer, F.; Paglione, R.W.

1984-01-01

Heating patterns as a function of regional blood flow were evaluated in healthy tissues with different vascular characteristics as well as in a variety of tumors submitted to microwave and RF-induced hyperthermia. Generally, faster heating and slower cooling was demonstrated for tumors. Definite correlation was found between the power needed to heat given tissue volume to a specific temperature and the ability of this tissue to dissipate heat via vascular flow. The measurements show that during the early phase of heating of tumors temperature rises slowly up to about 40 0 C. indicating good heat exchanges but that at this level rapid increase of temperature occurs for relatively small increments of power input. It is suggested that blood flow in malignant tissue remains competent and responsive to low grade heating, but that at higher temperature levels, in contrast to normal tissue, tumor blood flow rapidly decreases indicating compromised vascular system. Implication for treatment protocols are discussed

Quantitative effects of rapid heating on soot-particle sizing through analysis of two-pulse LII

KAUST Repository

Cenker, Emre

2017-02-27

During the rapid laser pulse heating and consecutive cooling in laser-induced incandescence (LII), soot particles may undergo thermal annealing and sublimation processes which lead to a permanent change in its optical properties and its primary particle size, respectively. Overall, effects of these two processes on soot and LII model-based particle sizing are investigated by measuring the two-color time-resolved (2C-TiRe) LII signal decay from in-flame soot after two consecutive laser pulses at 1064-nm wavelength. Experiments are carried out on a non-premixed laminar ethylene/air flame from a Santoro burner with both low and moderate laser fluences suitable for particle sizing. The probe volume is set to a radial position close to the flame axis where the soot particles are known to be immature or less graphitic. With the first pulse, soot is pre-heated, and the LII signal after the consecutive second pulse is used for analysis. The two-color incandescence emission technique is used for the pyrometric determination of the LII-heated peak soot temperature at the second pulse. A new LII simulation tool is developed which accounts for particle heating via absorption and annealing, and cooling via sublimation, conduction, and radiation with various existing sub-models from the literature. The same approach of using two laser pulses is implemented in the simulations. Measurements indicate that thermal annealing and associated absorption enhancement becomes important at laser fluences above 0.17 J/cm2 for the immature in-flame soot. After a heating pulse at 0.33 J/cm2, the increase of the soot absorption function is calculated as 35% using the temperature measured at the second pulse and an absorption model based on the Rayleigh approximation. Present annealing model, on the other hand, predicts graphitization of soot even in the absence of laser heating at typical flame temperatures. Recorded experimental LII signal decays and LII-heated peak soot temperature

Thin film ceramic thermocouples

Science.gov (United States)

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

2011-01-01

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

Thin films of copper antimony sulfide: A photovoltaic absorber material

Energy Technology Data Exchange (ETDEWEB)

Ornelas-Acosta, R.E. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Shaji, S. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico)

2015-01-15

Highlights: • CuSbS{sub 2} thin films were prepared by heating Sb{sub 2}S{sub 3}/Cu layers. • Analyzed the structure, composition, optical, and electrical properties. • PV structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag were formed at different conditions. • The PV parameters (J{sub sc}, V{sub oc}, and FF) were evaluated from the J–V characteristics. • J{sub sc}: 0.52–3.20 mA/cm{sup 2}, V{sub oc}:187–323 mV, FF: 0.27–0.48 were obtained. - Abstract: In this work, we report preparation and characterization of CuSbS{sub 2} thin films by heating glass/Sb{sub 2}S{sub 3}/Cu layers and their use as absorber material in photovoltaic structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag. The Sb{sub 2}S{sub 3} thin films of 600 nm were prepared by chemical bath deposition on which copper thin films of 50 nm were thermally evaporated, and the glass/Sb{sub 2}S{sub 3}/Cu multilayers were heated in vacuum at different temperatures. X-ray diffraction analysis showed the formation of orthorhombic CuSbS{sub 2} after heating the precursor layers. Studies on identification and chemical state of the elements were done using X-ray photoelectron spectroscopy. The optical band gap of the CuSbS{sub 2} thin films was 1.55 eV and the thin films were photoconductive. The photovoltaic parameters of the devices using CuSbS{sub 2} as absorber and CdS as window layer were evaluated from the J–V curves, yielding J{sub sc}, V{sub oc}, and FF values in the range of 0.52–3.20 mA/cm{sup 2}, 187–323 mV, and 0.27–0.48, respectively, under illumination of AM1.5 radiation.

Rapid quantitative analysis of elemental composition and depth profile of Cu(In,Ga)Se{sub 2} thin solar cell film using laser-induced breakdown spectroscopy

Energy Technology Data Exchange (ETDEWEB)

In, Jung-Hwan; Kim, Chan-Kyu; Lee, Seok-Hee; Choi, Jang-Hee; Jeong, Sungho, E-mail: shjeong@gist.ac.kr

2015-03-31

Laser-induced breakdown spectroscopy (LIBS) is reported as a method for rapid quantitative analysis of elemental composition and depth profile of Cu(In,Ga)Se{sub 2} (CIGS) thin film. A calibration model considering compositional grading over depth was developed and verified with test samples. The results from eight test samples showed that the average concentration of Cu, In, Ga and Se could be predicted with a root mean square error of below 1% and a relative standard deviation of also below 1%. The depth profile of each constituent element of CIGS predicted by LIBS was close to those by Auger electron spectroscopy and secondary ion mass spectrometry. The average ablation depth per pulse during depth profiling was about 100 nm. - Highlights: • LIBS was adopted for quantitative analysis of CIGS thin film. • A calibration model considering compositional grading over depth was developed. • Concentration prediction of CIGS thin film was accurate and precise. • Quantitative depth profiling by LIBS was compared with those by AES and SIMS.

Application of heat pump by using the earth temperature gradient for winter heating and summer cooling

International Nuclear Information System (INIS)

Gacevski, Marijan; Tanev, Pepi

2003-01-01

Because of the rapid technique development as well as modern human life, in order to satisfy the energy needs it is necessary to use a new apparatus and devices. In this manner, the electric power consumption, especially for heating and cooling, rapidly increases. One of the possible ways to reduce the consumption of electric energy for heating and cooling is that, to use heat pumps. In this paper a heat pump that uses the heat of the earth by a horizontal polyethylene pipe heat exchanger is proposed. Also, all parameters are examined and comparison with already existing ones is done. The heat gradient of the earth in spite of saving electrical energy is analyzed as well. (Original)

Numerical simulation of fluid flow and heat transfer in a thin liquid film over a stationary and rotating disk and comparison with experimental data

Science.gov (United States)

Faghri, Amir; Swanson, Theodore D.

1990-01-01

In the first section, improvements in the theoretical model and computational procedure for the prediction of film height and heat-transfer coefficient of the free surface flow of a radially-spreading thin liquid film adjacent to a flat horizontal surface of finite extent are presented. Flows in the presence and absence of gravity are considered. Theoretical results are compared to available experimental data with good agreement. In the presence of gravity, a hydraulic jump is present, isolating the flow into two regimes: supercritical upstream from the jump and subcritical downstream of it. In this situation, the effects of surface tension are important near the outer edge of the disk where the fluid experiences a free fall. A region of flow separation is present just downstream of the jump. In the absence of gravity, no hydraulic jump or separated flow region is present. The variation of the heat-transfer coefficient for flows in the presence and absence of gravity are also presented. In the second section, the results of a numerical simulation of the flow field and associated heat transfer coefficients are presented for the free surface flow of a thin liquid film adjacent to a horizontal rotating disk. The computation was performed for different flow rates and rotational velocities using a 3-D boundary-fitted coordinate system. Since the geometry of the free surface is unknown and dependent on flow rate, rate of rotation, and other parameters, an iterative procedure had to be used to ascertain its location. The computed film height agreed well with existing experimental measurements. The flow is found to be dominated by inertia near the entrance and close to the free surface and dominated by centrifugal force at larger radii and adjacent to the disk. The rotation enhances the heat transfer coefficient by a significant amount.

Measurement errors for thermocouples attached to thin plates

International Nuclear Information System (INIS)

Sobolik, K.B.; Keltner, N.R.; Beck, J.V.

1989-01-01

This paper discusses Unsteady Surface Element (USE) methods which are applied to a model of a thermocouple wire attached to a thin disk. Green's functions are used to develop the integral equations for the wire and the disk. The model can be used to evaluate transient and steady state responses for many types of heat flux measurement devices including thin skin calorimeters and circular foil (Gardon) head flux gauges. The model can accommodate either surface or volumetric heating of the disk. The boundary condition at the outer radius of the disk can be either insulated or constant temperature. Effect on the errors of geometrical and thermal factors can be assessed. Examples are given

The inaccuracy of heat transfer characteristics for non-insulated and insulated spherical containers neglecting the influence of heat radiation

International Nuclear Information System (INIS)

Wong, King-Leung; Salazar, Jose Luis Leon; Prasad, Leo; Chen, Wen-Lih

2011-01-01

In this investigation, the differences of heat transfer characteristics for insulated and non-insulated spherical containers between considering and neglecting the influence of heat radiation are studied by the simulations in some practical situations. It is found that the heat radiation effect cannot be ignored in conditions of low ambient convection heat coefficients (such ambient air) and high surface emissivities, especially for the non-insulated and thin insulated cases. In most practical situations when ambient temperature is different from surroundings temperature and the emissivity of insulation surface is different from that of metal wall surface, neglecting heat radiation will result in inaccurate insulation effect and heat transfer errors even with very thick insulation. However, the insulation effect considering heat radiation will only increase a very small amount after some dimensionless insulated thickness (such insulation thickness/radius ≥0.2 in this study), thus such dimensionless insulated thickness can be used as the optimum thickness in practical applications. Meanwhile, wrapping a material with low surface emissivity (such as aluminum foil) around the oxidized metal wall or insulation layer (always with high surface emissivity) can achieve very good insulated effect for the non-insulated or thin insulated containers.

Textured indium tin oxide thin films by chemical solution deposition and rapid thermal processing

International Nuclear Information System (INIS)

Mottern, Matthew L.; Tyholdt, Frode; Ulyashin, Alexander; Helvoort, Antonius T.J. van; Verweij, Henk; Bredesen, Rune

2007-01-01

The microstructure of state-of-the-art chemical solution deposited indium tin oxide thin films typically consists of small randomly oriented grains, high porosity and poor homogeneity. The present study demonstrates how the thin film microstructure can be improved significantly by tailoring the precursor solutions and deposition conditions to be kinetically and thermodynamically favorable for generation of homogeneous textured thin films. This is explained by the occurrence of a single heterogeneous nucleation mechanism. The as-deposited thin films, crystallized at 800 deg. C, have a high apparent density, based on a refractive index of ∼ 1.98 determined by single wavelength ellipsometry at 633 nm. The microstructure of the films consists of columnar grains with preferred orientation as determined by X-ray diffraction and transmission electron microscopy. The resistivity, measured by the four point probe method, is ∼ 2 x 10 -3 Ω cm prior to post-deposition treatments

Heat flow study of the Emeishan large igneous province region: Implications for the geodynamics of the Emeishan mantle plume

Science.gov (United States)

Jiang, Qiang; Qiu, Nansheng; Zhu, Chuanqing

2018-01-01

The Emeishan large igneous province (ELIP) is widely considered to be a consequence of a mantle plume. The supporting evidence includes rapid emplacement, voluminous flood basalt eruptions, and high mantle potential temperature estimates. Several studies have suggested that there was surface uplift prior to the eruption of the Emeishan flood basalts. Additionally, the plume's lateral extent is hard to constrain and has been variously estimated to be 800-1400 km in diameter. In this study, we analyzed present-day heat flow data and reconstructed the Permian paleo-heat flow using vitrinite reflectance and zircon (U-Th)/He thermochronology data in the ELIP region and discussed implications for the geodynamics of the Emeishan mantle plume. The present-day heat flow is higher in the inner and intermediate zones than in the outer zone, with a decrease of average heat flow from 76 mW/m2 to 51 mW/m2. Thermal history modeling results show that an abnormal high paleo-heat flow of 90-110 mW/m2 was caused by the Emeishan mantle plume activity. Based on the present-day heat flow data, we can calculate that there is lithospheric thinning in the central ELIP region, which may be due to the destruction of the lithosphere by mantle plume upwelling and magmatic underplating. The Permian paleo-heat flow anomaly implies that there was a temperature anomaly in the mantle. The ascending high-temperature mantle plume and the thinned lithosphere may have induced the large-scale uplift in the ELIP region. According to the range of the surface heat flow anomaly, it can be estimated that the diameter of the flattened head of the Emeishan mantle plume could have reached 1600-1800 km. Our research provides new insights into the geodynamics of the Emeishan mantle plume through study of heat flow.

Compact interior heat exchangers for CO{sub 2} mobile heat pumping systems

Energy Technology Data Exchange (ETDEWEB)

Hafner, Armin

2003-07-01

The natural refrigerant carbon dioxide (CO{sub 2}) offers new possibilities for design of flexible, efficient and environmentally safe mobile heat pumping systems. As high-efficient car engines with less waste heat are developed, extra heating of the passenger compartment is needed in the cold season. A reversible transcritical CO{sub 2} system with gliding temperature heat rejection can give high air delivery temperature which results in rapid heating of the passenger compartment and rapid defogging or defrosting of windows. When operated in cooling mode, the efficiency of transcritical CO{sub 2} systems is higher compared to common (HFC) air conditioning systems, at most dominant operating conditions. Several issues were identified for the design of compact interior heat exchangers for automotive reversible CO{sub 2} heat pumping systems. Among theses issues are: (1) Refrigerant flow distribution, (2) Heat exchanger fluid flow circuiting, (3) Air temperature uniformity downstream of the heat exchanger, (4) Minimization of temperature approach, (5) Windshield flash fogging due to retained water inside the heat exchanger, (6) Internal beat conduction in heating mode operation, and (7) Refrigerant side pressure drop In order to provide a basis for understanding these issues, the author developed a calculation model and set up a test facility and investigated different prototype heat exchangers experimentally.

Ageing Management Programme: An Experience of In-Service Inspection of the Kartini Heat Exchanger

Energy Technology Data Exchange (ETDEWEB)

Nitiswati, S., E-mail: nitis@batan.go.id [Centre for Reactor Technology and Nuclear Safety, National Nuclear Energy Agency (BATAN), Jakarta (Indonesia); Syarip,; Tjiptono, T.; Wantana, [Centre for Accelerator and Material Process Technology, National Nuclear Energy Agency (BATAN), Yogyakarta (Indonesia)

2014-08-15

This paper discusses an experience on ISI of the Kartini reactor heat exchanger, as part of the implementation of an ageing management programme. Kartini reactor is located in Yogyakarta, Indonesia. The heat exchanger was constructed for 250 kW capacity. The type of heat exchanger is shell with tube recirculation. Tube material is stainless steel 304, and the shell and baffle plate materials are carbon steel. The heat exchanger has 72 tubes, its outer and inner diameters respectively are 19 and 16 mm, and tube thickness is 1.5 mm. The aim of ISI was to obtain and evaluate the heat exchanger’s condition including the detection of any possible local tube thinning, pitting corrosion or gradual thinning, and determine whether any degradation or deterioration of the heat exchanger could have a significant impact to safety. The heat exchanger was inspected utilizing eddy current equipment in 2003 and 2006. Inspection results in 2003 determined that 12 heat exchanger tubes have a thinning degradation level ranging from 10% up to 60% of the outer diameter due to pitting corrosion. Deterioration of baffle plates has been linked to general corrosion attack. Inspection results in 2006 showed a consistent thinning degradation level with the previous inspection in 2003. So far heat exchanger performance is still satisfactory, as defined by the transfer of primary heat for a 2°C difference between inlet and outlet as required. (author)

Controlled bending and folding of a bilayer structure consisting of a thin stiff film and a heat shrinkable polymer sheet

Science.gov (United States)

Cui, Jianxun; Adams, John G. M.; Zhu, Yong

2018-05-01

Bending pre-designed flat sheets into three-dimensional (3D) structures is attracting much interest, as it provides a simple approach to make 3D devices. Here we report controlled bending and folding of a bilayer structure consisting of a heat shrinkable polymer sheet and a thin stiff film (not thermally responsive). Upon heating, the prestrained polymer sheet shrinks, leading to bending or folding of the bilayer. We studied the effect of relative dimensions of the two layers on the bending behavior and demonstrated the transition from longitudinal bending to transverse bending of the bilayer strip. Transverse bending was utilized to fold origami structures, including several flat letters, a crane, and a corrugated metal sheet via Miura-ori folding. We developed a method to further control the bending orientation based on bio-inspired anisotropic bending stiffness. By bending the metal foil in different orientations, several structures were obtained, including cylindrical surfaces and left-handed/right-handed helical structures.

Sensors for Metering Heat Flux Area Density and Metrological Equipment for the Heat Flux Density Measurement

Science.gov (United States)

Doronin, D. O.

2018-04-01

The demand in measuring and studies of heat conduction of various media is very urgent now. This article considers the problem of heat conduction monitoring and measurement in various media and materials in any industries and branches of science as well as metrological support of the heat flux measurement equipment. The main study objects are both the sensors manufactured and facilities onto which these sensors will be installed: different cladding structures of the buildings, awnings, rocket fairings, boiler units, internal combustion engines. The Company develops and manufactures different types of heat flux sensors: thermocouple, thin-film, heterogeneous gradient as well as metrological equipment for the gauging calibration of the heat flux density measurement. The calibration shall be performed using both referencing method in the unit and by fixed setting of the heat flux in the unit. To manufacture heterogeneous heat flux gradient sensors (HHFGS) the Company developed and designed a number of units: diffusion welding unit, HHFGS cutting unit. Rather good quality HHFGS prototypes were obtained. At this stage the factory tests on the equipment for the heat flux density measurement equipment are planned. A high-sensitivity heat flux sensor was produced, now it is tested at the Construction Physics Research Institute (Moscow). It became possible to create thin-film heat flux sensors with the sensitivity not worse than that of the sensors manufactured by Captec Company (France). The Company has sufficient premises to supply the market with a wide range of sensors, to master new sensor manufacture technologies which will enable their application range.

Measurement of a surface heat flux and temperature

Science.gov (United States)

Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

1994-04-01

The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The

Weight restoration therapy rapidly reverses cortical thinning in anorexia nervosa: A longitudinal study.

Science.gov (United States)

Bernardoni, Fabio; King, Joseph A; Geisler, Daniel; Stein, Elisa; Jaite, Charlotte; Nätsch, Dagmar; Tam, Friederike I; Boehm, Ilka; Seidel, Maria; Roessner, Veit; Ehrlich, Stefan

2016-04-15

Structural magnetic resonance imaging studies have documented reduced gray matter in acutely ill patients with anorexia nervosa to be at least partially reversible following weight restoration. However, few longitudinal studies exist and the underlying mechanisms of these structural changes are elusive. In particular, the relative speed and completeness of brain structure normalization during realimentation remain unknown. Here we report from a structural neuroimaging study including a sample of adolescent/young adult female patients with acute anorexia nervosa (n=47), long-term recovered patients (n=34), and healthy controls (n=75). The majority of acutely ill patients were scanned longitudinally (n=35): at the beginning of standardized weight restoration therapy and again after partial weight normalization (>10% body mass index increase). High-resolution structural images were processed and analyzed with the longitudinal stream of FreeSurfer software to test for changes in cortical thickness and volumes of select subcortical regions of interest. We found globally reduced cortical thickness in acutely ill patients to increase rapidly (0.06 mm/month) during brief weight restoration therapy (≈3 months). This significant increase was predicted by weight restoration alone and could not be ascribed to potentially mediating factors such as duration of illness, hydration status, or symptom improvements. By comparing cortical thickness in partially weight-restored patients with that measured in healthy controls, we confirmed that cortical thickness had normalized already at follow-up. This pattern of thinning in illness and rapid normalization during weight rehabilitation was largely mirrored in subcortical volumes. Together, our findings indicate that structural brain insults inflicted by starvation in anorexia nervosa may be reversed at a rate much faster than previously thought if interventions are successful before the disorder becomes chronic. This provides

Transient heat transfer characteristics of liquid helium

International Nuclear Information System (INIS)

Tsukamoto, Osami

1976-01-01

The transient heat transfer characteristics of liquid helium are investigated. The critical burnout heat fluxes for pulsive heating are measured, and empirical relations between the critical burnout heat flux and the length of the heat pulse are given. The burnout is detected by observing the super-to-normal transition of the temperature sensor which is a thin lead film prepared on the heated surface by vacuum evaporation. The mechanism of boiling heat transfer for pulsive heating is discussed, and theoretical relations between the critical burnout heat flux and the length of the heat pulse are derived. The empirical data satisfy the theoretical relations fairly well. (auth.)

Study of nanocluster-assembled ZnO thin films by nanocluster-beam deposition

Energy Technology Data Exchange (ETDEWEB)

Zhao, Zhiwei; Lei, Wei; Zhang, Xiaobing [School of Electronic Science and Engieering, Southeast University, Nanjing (China); Tay, Beng Kang [School of Electronical and Electronic Engineering, Nanyang Technological University, Nanyang (Singapore)

2012-01-15

Nanocluster-assembled ZnO thin films were obtained by nanocluster-beam deposition, in which nanoclusters were produced by a magnetron sputtering gas aggregation source. Two kinds of ZnO thin films were obtained using this method with the one grown under the on-line heating temperature of 700 C, and the other grown without on-line heating. Film microstructure and optical properties are investigated by various diagnostic techniques. It was found that both of film microstructure of ZnO thin films keep wurtzite structure as that of ZnO bulk materials. The averaged particle size for the film grown without on-line heating is around 6 nm, which is a little lower than that grown with the on-line heating. It was also found that as increasing the wavelength, both of the absorbance spectra for the films decrease sharply near ultra-visible to extend slowly to the visible and infrared wavelength range. For the film grown without on-line heating, the bandgap energy was estimated to 3.77 eV, while for the film grown with on-line heating, the bandgap energy was redshift to 3.71 eV. Similar behavior was also found for PL spectra analysis, where PL spectrum exhibited a peak centered at 3.31 eV without on-line heating, while it redshift to 3.20 eV with on-line heating. The mechanisms behind these behaviors were presented in this article. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Evaluation of the thin agar layer method for the recovery of pressure-injured and heat-injured Listeria monocytogenes.

Science.gov (United States)

Lavieri, Nicolas A; Sebranek, Joseph G; Cordray, Joseph C; Dickson, James S; Jung, Stephanie; Manu, David K; Mendonça, Aubrey F; Brehm-Stecher, Byron F; Stock, Joseph; Stalder, Kenneth J

2014-05-01

A sublethally injured bacterial cell has been defined as a cell that survives a stress such as heating, freezing, acid treatment, or other antimicrobial intervention but can repair the cellular damage exerted by the stressor and later regain its original ability to grow. Consequently, sublethally injured cells are not likely to be included in conventional enumeration procedures, which could result in unrealistically low counts unless efforts are made to encourage recovery of the injured cells before enumeration. The objective of this study was to evaluate the use of the thin agar layer (TAL) method for the recovery of pressure-injured and heat-injured Listeria monocytogenes in a tryptic soy broth with 0.6% yeast extract system. Pressure injury consisted of treatment of a culture of mixed L. monocytogenes strains with high hydrostatic pressure at 400 or 600 MPa for 1 s, 2 min, 4 min, or 6 min at a process temperature of 12±2 °C. Heat injury consisted of treatment of a culture of mixed L. monocytogenes strains at 60±1 °C for 3, 6, or 9 min. Growth media were tryptic soy agar (TSA) with 0.6% yeast extract, modified Oxford medium (MOX), and TAL, which consisted of a 7-ml layer of TSA overlaid onto solidified MOX. Counts of viable L. monocytogenes on TAL were higher than those on MOX in the heat-injury experiment but not in the pressure-injury experiment. Therefore, the effectiveness of the TAL method may be specific to the type of injury applied to the microorganism and should be investigated in a variety of cellular injury scenarios.

Heat treatment and thickness-dependent electrical study of Se{sub 50}Te{sub 20}S{sub 30} thin film

Energy Technology Data Exchange (ETDEWEB)

Abd-Elrahman, M.I.; Hafiz, M.M.; Qasem, Ammar; Abdel-Rahim, M.A. [Assiut University, Physics Department, Faculty of Science, Assiut (Egypt)

2016-08-15

Chalcogenide Se{sub 50}Te{sub 20}S{sub 30} thin film of different thickness was deposited using thermal evaporation technique. The thermogram of the chalcogenide bulk Se{sub 50}Te{sub 20}S{sub 30} was obtained using a differential scanning calorimetry (DSC) with heating rate of 7.5 K/min. The glass transition temperature T{sub g}, crystallization temperature T{sub c} and peak crystallization temperature T{sub p} were identified. The X-ray diffraction (XRD) examination indicates the amorphous nature of the as-deposited film and polycrystalline structure of the thermal annealed ones. The dark electrical resistivity (ρ) measurements were taken in temperature range (300-500 K) and thickness range (200-450 nm). Analysis of the electrical resistivity results revealed two types of conduction mechanisms: conduction due to extended states in the temperature range (T > T{sub c}) and variable range hopping in the temperature range (T < T{sub c}). The effect of the heat treatment and thickness on the density of localized states at the Fermi level N(E{sub F}) and hopping parameters were studied. (orig.)

Thin-layer agar (TL7H11 for rapid isolation of Mycobacterium tuberculosis in sputum specimens

Directory of Open Access Journals (Sweden)

Habiba Binte Alam

2016-08-01

Full Text Available Background: Tuberculosis (TB remains one of the major causes of death from a single infectious agent worldwide. The early detection of new cases of pulmonary tuberculosis is an important goal in tuberculosis control program.Objective: 1n this study, thin layer agar (TLA culture was compared with Lowenstein-Jensen (LJ culture for rapid detection of pulmonary tuberculosis. Methods: It was a cross sectional study conducted in National Tuberculosis Reference Labora­tory (NTRL of National Institute of Disease of Chest and Hospital (NIDCH, Dhaka, from July 2010 to June 2011. A total of 100 sputum smear positive for acid fast bacilli (AFB by Z-N staining, pulmonary tuberculosis patients were included in this study. Samples were processed by modified Petroff method and then cultured on thin layer 7H11(TL7H11 plates and L-J tubes. TL7H11 plates were observed microscopically for rnicrocolony growth once a week for 6 weeks, and L-J tubes were observed once a week for 8 weeks. Results: The recovery rates of mycobacteria on only TLA, only LJ and on both media were 90%, 97% and 88% respectively. Overall positivity was 99% in both L-J and TLA media. Mean time for detection of mycobacteria on TLA was 9.04±1.66 days compared to 21.78±6.19 days on L-J media. The rate of contamination was higher (6% in L-J media than in TLA media (4%. Conclusion: The TL7H11 media can be used as an alternative to the Lowenstein-Jensen medium for early isolation of mycobacteria in resource constrained settings.

Study on Induction Heating Coil for Uniform Mold Cavity Surface Heating

OpenAIRE

Yu-Ting Sung; Sheng-Jye Hwang; Huei-Huang Lee; Durn-Yuan Huang

2014-01-01

Recently, energy saving is one of the important issues for polymer processing industry. Electromagnetic induction heating has many advantages such as fast heating and low energy consumption. Previous studies using electromagnetic induction heating for rapid tool heating have indicated that the temperature uniformity on a cavity surface is not easy to be achieved. In this paper, two different coils were used for heating uniform 7 mm thick hot work tool steel (JIS SKD61) surface. One is a four-...

Heat-Related Illnesses

Medline Plus

Full Text Available ... exhaustion symptoms include cool, moist, pale or flushed skin; headache; dizziness; weakness; feeling exhausted; heavy sweating; nausea; ... stage of heat illness) include flushed, hot, dry skin; fainting; a rapid, weak pulse; rapid, shallow breathing; ...

Cathodic electrodeposition of CuInSe sub 2 thin films

Energy Technology Data Exchange (ETDEWEB)

Guillen, C; Galiano, E; Herrero, J [Inst. de Energias Renovables (CIEMAT), Madrid (Spain)

1991-01-01

In order to study the preparation process of CuInSe{sub 2} thin films by a one-step electrodeposition method, thin films of the compound were prepared from aqueous citric acid (C{sub 6}H{sub 8}O{sub 7} . H{sub 2}O) plating baths onto titanium substrates. During electrodeposition, the bath composition and deposition potential were changed to obtain stoichiometric thin films. In general, close to stoichiometry, layers rich in selenium were observed, and this excess of selenium was removed after heat treatment. Best quality films were obtained after annealing at 400deg C during 15 min. X-ray diffraction showed the formation of CuInSe{sub 2} films, the chalcopyrite structure, at heating treatment temperatures higher than 350deg C. Optical measurements showed that the band gap of the deposited material was 0.99 eV. (orig.).

The evolution of droplet impacting on thin liquid film at superhydrophilic surface

Science.gov (United States)

Li, Yun; Zheng, Yi; Lan, Zhong; Xu, Wei; Ma, Xuehu

2017-12-01

Thin films are ubiquitous in nature, and the evolution of a liquid film after droplet impact is critical in many industrial processes. In this paper, a series of experiments and numerical simulations are conducted to investigate the distribution and evolution features of local temperature as the droplet impacts a thin film on the superhydrophilic surface by the thermal tracing method. A cold area is formed in the center after droplet impacts on heated solid surfaces. For the droplet impact on thin heated liquid film, a ring-shaped low temperature zone is observed in this experiment. Meanwhile, numerical simulation is adopted to analyze the mechanism and the interaction between the droplet and the liquid film. It is found that due to the vortex velocity distribution formed inside the liquid film after the impact, a large part of the droplet has congested. The heating process is not obvious in the congested area, which leads to the formation of a low-temperature area in the results.

TEM Characterization and Properties of Cu-1 wt.% TiB2 Nanocomposite Prepared by Rapid Solidification and Subsequent Heat Treatment

Directory of Open Access Journals (Sweden)

M. Sobhani

2012-12-01

Full Text Available Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to the formation of secondary TiB2 particles via spinodal decomposition of titanium-rich zone inside the grains. Mechanical properties (after 50% reduction in area as well as electrical conductivity of composite were evaluated after heat treatment and were compared with those of pure copper. The results indicated that, due to the formation of secondary TiB2 particles in the matrix, electrical conductivity increased along with hardness up to 10 hrs of heat treatment and reached 65% IACS and 155 HV, respectively. Moreover, the maximum ultimate (i.e. 580 MPa and yield (i.e. 555 MPa strengths of composite were achieved at this time.

Rapid Tooling via Stereolithography

OpenAIRE

Montgomery, Eva

2006-01-01

Approximately three years ago, composite stereolithography (SL) resins were introduced to the marketplace, offering performance features beyond what traditional SL resins could offer. In particular, the high heat deflection temperatures and high stiffness of these highly filled resins have opened the door to several new rapid prototyping (RP) applications, including wind tunnel test modelling and, more recently, rapid tooling.

Characterization of Mycobacterium paratuberculosis by gas-liquid and thin-layer chromatography and rapid demonstration of mycobactin dependence using radiometric methods

International Nuclear Information System (INIS)

Damato, J.J.; Knisley, C.; Collins, M.T.

1987-01-01

Thirty-six Mycobacterium paratuberculosis isolates of bovine, caprine, and ovine origins were evaluated by using gas-liquid chromatography (GLC), thin-layer chromatography (TLC), and BACTEC 7H12 Middlebrook TB medium in an effort to more rapidly differentiate this group of organisms from other mycobacteria. Bacterial suspensions (0.1 ml) were inoculated by syringe into 7H12 broth containing 2 micrograms of mycobactin P per ml and control broth without mycobactin P. Cultures were incubated at 37 0 C and read daily with a BACTEC Model 301. After 8 days of incubation, the growth index readings for the test broths containing mycobactin P were twice those of the control broths without mycobactin P. Sixty-five isolates of mycobacteria other than M. paratuberculosis were also examined. No difference was noted between the growth index readings of control and mycobactin-containing broths. Except for Mycobacterium avium-Mycobacterium intracellulare, TLC studies differentiated M. paratuberculosis from the other mycobacterial species tested. The GLC data reveal that all M. paratuberculosis isolates had a distinctive peak (14A) which was not found among M. avium-M. intracellulare complex organisms. These data indicate that 7H12 radiometric broth was able to rapidly demonstrate the mycobactin dependence of M. paratuberculosis and GLC and TLC procedures were capable of rapidly differentiating this organism from the other mycobacteria studied

Carbonyl Compounds Produced by Vaporizing Cannabis Oil Thinning Agents.

Science.gov (United States)

Troutt, William D; DiDonato, Matthew D

2017-11-01

Cannabis use has increased in the United States, particularly the use of vaporized cannabis oil, which is often mixed with thinning agents for use in vaporizing devices. E-cigarette research shows that heated thinning agents produce potentially harmful carbonyls; however, similar studies have not been conducted (1) with agents that are commonly used in the cannabis industry and (2) at temperatures that are appropriate for cannabis oil vaporization. The goal of this study was to determine whether thinning agents used in the cannabis industry produce potentially harmful carbonyls when heated to a temperature that is appropriate for cannabis oil vaporization. Four thinning agents (propylene glycol [PG], vegetable glycerin [VG], polyethylene glycol 400 [PEG 400], and medium chain triglycerides [MCT]) were heated to 230°C and the resulting vapors were tested for acetaldehyde, acrolein, and formaldehyde. Each agent was tested three times. Testing was conducted in a smoking laboratory. Carbonyl levels were measured in micrograms per puff block. Analyses showed that PEG 400 produced significantly higher levels of acetaldehyde and formaldehyde than PG, MCT, and VG. Formaldehyde production was also significantly greater in PG compared with MCT and VG. Acrolein production did not differ significantly across the agents. PG and PEG 400 produced high levels of acetaldehyde and formaldehyde when heated to 230°C. Formaldehyde production from PEG 400 isolate was particularly high, with one inhalation accounting for 1.12% of the daily exposure limit, nearly the same exposure as smoking one cigarette. Because PG and PEG 400 are often mixed with cannabis oil, individuals who vaporize cannabis oil products may risk exposure to harmful formaldehyde levels. Although more research is needed, consumers and policy makers should consider these potential health effects before use and when drafting cannabis-related legislation.

Method for the manufacture of a thin film electrochemical energy source and device

NARCIS (Netherlands)

2008-01-01

The invention relates to a method for the manuf. of a thin film electrochem. energy source. The invention also relates to a thin film electrochem. energy source. The invention also relates to an elec. device comprising such a thin film electrochem. energy source. The invention enables a more rapid

Can cognitive dissonance methods developed in the West for combatting the 'thin ideal' help slow the rapidly increasing prevalence of eating disorders in non-Western cultures?

Science.gov (United States)

Witcomb, Gemma L; Arcelus, Jon; Chen, Jue

2013-12-01

Eating disorders are common, life-threatening conditions in Western countries, but until relatively recently they were regarded as uncommon in non-Western cultures. However, the prevalence of eating disorders in many of the more affluent non-Western countries is rising rapidly as community members, particularly young women, internalize the 'thin ideal' that has been widely promoted by the international media. This review discusses the factors involved in the development of eating disorders in non-Western settings with a particular emphasis on the influences of urbanization, modernization, Westernization, and the resulting changes in women's roles. The cognitive dissonance programs developed in Western countries that have proven successful in countering the negative effects of the thin idea are described and their potential application to East Asia and other non-Western countries are discussed.

Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora

International Nuclear Information System (INIS)

Johnson, Jay R.; Okuda, Hideo

2008-01-01

Nearly half of the time, auroral displays exhibit thin, bright layers known as 'enhanced aurora'. There is a substantial body of evidence that connects these displays with thin, dense, heavy ion layers in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that they result when wave-particle interaction heats ambient electrons to energies at or just above the 17 eV ionization energy of N2. While there are several possible instabilities that could produce suprathermal electrons in thin layers, there has been no clear theoretical investigation which examines in detail how wave instabilities in the thin ionization layers could develop and produce the suprathermal electrons. We examine instabilities which would occur in thin, dense, heavy ion layers using extensive analytical analysis combined with particle simulations. We analyze a cross field current instability that is found to be strongly unstable in the heavy ion layers. Electrostatic simulations show that substantial heating of the ambient electrons occurs with energization at or above the N2 ionization energy.

Rapid thermal process by RF heating of nano-graphene layer/silicon substrate structure: Heat explosion theory approach

Science.gov (United States)

Sinder, M.; Pelleg, J.; Meerovich, V.; Sokolovsky, V.

2018-03-01

RF heating kinetics of a nano-graphene layer/silicon substrate structure is analyzed theoretically as a function of the thickness and sheet resistance of the graphene layer, the dimensions and thermal parameters of the structure, as well as of cooling conditions and of the amplitude and frequency of the applied RF magnetic field. It is shown that two regimes of the heating can be realized. The first one is characterized by heating of the structure up to a finite temperature determined by equilibrium between the dissipated loss power caused by induced eddy-currents and the heat transfer to environment. The second regime corresponds to a fast unlimited temperature increase (heat explosion). The criterions of realization of these regimes are presented in the analytical form. Using the criterions and literature data, it is shown the possibility of the heat explosion regime for a graphene layer/silicon substrate structure at RF heating.

Rapid, simple, and highly sensitive analysis of drugs in biological samples using thin-layer chromatography coupled with matrix-assisted laser desorption/ionization mass spectrometry.

Science.gov (United States)

Kuwayama, Kenji; Tsujikawa, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

2012-01-01

Rapid and precise identification of toxic substances is necessary for urgent diagnosis and treatment of poisoning cases and for establishing the cause of death in postmortem examinations. However, identification of compounds in biological samples using gas chromatography and liquid chromatography coupled with mass spectrometry entails time-consuming and labor-intensive sample preparations. In this study, we examined a simple preparation and highly sensitive analysis of drugs in biological samples such as urine, plasma, and organs using thin-layer chromatography coupled with matrix-assisted laser desorption/ionization mass spectrometry (TLC/MALDI/MS). When the urine containing 3,4-methylenedioxymethamphetamine (MDMA) without sample dilution was spotted on a thin-layer chromatography (TLC) plate and was analyzed by TLC/MALDI/MS, the detection limit of the MDMA spot was 0.05 ng/spot. The value was the same as that in aqueous solution spotted on a stainless steel plate. All the 11 psychotropic compounds tested (MDMA, 4-hydroxy-3-methoxymethamphetamine, 3,4-methylenedioxyamphetamine, methamphetamine, p-hydroxymethamphetamine, amphetamine, ketamine, caffeine, chlorpromazine, triazolam, and morphine) on a TLC plate were detected at levels of 0.05-5 ng, and the type (layer thickness and fluorescence) of TLC plate did not affect detection sensitivity. In addition, when rat liver homogenate obtained after MDMA administration (10 mg/kg) was spotted on a TLC plate, MDMA and its main metabolites were identified using TLC/MALDI/MS, and the spots on a TLC plate were visualized by MALDI/imaging MS. The total analytical time from spotting of intact biological samples to the output of analytical results was within 30 min. TLC/MALDI/MS enabled rapid, simple, and highly sensitive analysis of drugs from intact biological samples and crude extracts. Accordingly, this method could be applied to rapid drug screening and precise identification of toxic substances in poisoning cases and

Trapping ultracold gases near cryogenic materials with rapid reconfigurability

Energy Technology Data Exchange (ETDEWEB)

Naides, Matthew A.; Turner, Richard W.; Lai, Ruby A.; DiSciacca, Jack M.; Lev, Benjamin L. [Departments of Applied Physics and Physics and Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States)

2013-12-16

We demonstrate an atom chip trapping system that allows the placement and high-resolution imaging of ultracold atoms within microns from any ≲100 μm-thin, UHV-compatible material, while also allowing sample exchange with minimal experimental downtime. The sample is not connected to the atom chip, allowing rapid exchange without perturbing the atom chip or laser cooling apparatus. Exchange of the sample and retrapping of atoms has been performed within a week turnaround, limited only by chamber baking. Moreover, the decoupling of sample and atom chip provides the ability to independently tune the sample temperature and its position with respect to the trapped ultracold gas, which itself may remain in the focus of a high-resolution imaging system. As a first demonstration of this system, we have confined a 700-nK cloud of 8 × 10{sup 4} {sup 87}Rb atoms within 100 μm of a gold-mirrored 100-μm-thick silicon substrate. The substrate was cooled to 35 K without use of a heat shield, while the atom chip, 120 μm away, remained at room temperature. Atoms may be imaged and retrapped every 16 s, allowing rapid data collection.

Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

International Nuclear Information System (INIS)

Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon; Fu, Dejun; Yoon, Hyungdo

2011-01-01

The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon [Dongguk University-Seoul, Seoul (Korea, Republic of); Fu, Dejun [Wuhan University, Wuhan (China); Yoon, Hyungdo [Korea Electronics Technology Institute, Seongnam (Korea, Republic of)

2011-10-15

The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

Microbubble-Triggered Spontaneous Separation of Transparent Thin Films from Substrates Using Evaporable Core-Shell Nanocapsules.

Science.gov (United States)

Son, Intae; Lee, Byungsun; Kim, Jae Hong; Kim, Chunho; Yoo, Ji Yong; Ahn, Byung Wook; Hwang, Jeongho; Lee, Jonghyuk; Lee, Jun Hyup

2018-05-23

The spontaneous separation of a polymer thin film from a substrate is an innovative technology that will enable material recycling and reduce manufacturing cost in the film industry, and this can be applied in a wide range of applications, from optical films to wearable devices. Here, we present an unprecedented spontaneous strategy for separating transparent polymer films from substrates on the basis of microbubble generation using nanocapsules containing an evaporable material. The core-shell nanocapsules are prepared from poly(methyl methacrylate)-polyethyleneimine nanoparticles via the encapsulation of methylcyclohexane (MCH). A spherical nanostructure with a vaporizable core is obtained, with the heat-triggered gas release ability leading to the formation of microbubbles. Our separation method applied to transparent polymer films doped with a small amount of the nanocapsules encapsulating evaporable MCH enables spontaneous detachment of thin films from substrates via vacuum-assisted rapid vaporization of MCH over a short separation time, and clear detachment of the film is achieved with no deterioration of the inherent optical transparency and adhesive property compared to a pristine film.

Heat flux microsensor measurements

Science.gov (United States)

Terrell, J. P.; Hager, J. M.; Onishi, S.; Diller, T. E.

1992-01-01

A thin-film heat flux sensor has been fabricated on a stainless steel substrate. The thermocouple elements of the heat flux sensor were nickel and nichrome, and the temperature resistance sensor was platinum. The completed heat flux microsensor was calibrated at the AEDC radiation facility. The gage output was linear with heat flux with no apparent temperature effect on sensitivity. The gage was used for heat flux measurements at the NASA Langley Vitiated Air Test Facility. Vitiated air was expanded to Mach 3.0 and hydrogen fuel was injected. Measurements were made on the wall of a diverging duct downstream of the injector during all stages of the hydrogen combustion tests. Because the wall and the gage were not actively cooled, the wall temperature reached over 1000 C (1900 F) during the most severe test.

Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

Science.gov (United States)

Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

2014-04-01

The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

Prediction of heat treatment in food processing machinery

DEFF Research Database (Denmark)

Karlson, Torben; Friis, Alan; Szabo, Peter

1997-01-01

The velocity and temperature fields of a shear thinning fluid in a co-rotating disc scraped surface heat exchanger (CDHE) are calculated using the finite element method. By tracking and timingparticles through the heat exchanger residence time and thermal time distributions are computed. The resi...

Theoretical models of Kapton heating in solar array geometries

Science.gov (United States)

Morton, Thomas L.

1992-01-01

In an effort to understand pyrolysis of Kapton in solar arrays, a computational heat transfer program was developed. This model allows for the different materials and widely divergent length scales of the problem. The present status of the calculation indicates that thin copper traces surrounded by Kapton and carrying large currents can show large temperature increases, but the other configurations seen on solar arrays have adequate heat sinks to prevent substantial heating of the Kapton. Electron currents from the ambient plasma can also contribute to heating of thin traces. Since Kapton is stable at temperatures as high as 600 C, this indicates that it should be suitable for solar array applications. There are indications that the adhesive sued in solar arrays may be a strong contributor to the pyrolysis problem seen in solar array vacuum chamber tests.

The thickness of DLC thin film affects the thermal conduction of HPLED lights

Science.gov (United States)

Hsu, Ming Seng; Huang, Jen Wei; Shyu, Feng Lin

2016-09-01

Thermal dissipation had an important influence in the quantum effect and life of light emitting diodes (LED) because it enabled heat transfer away from electric devices to the aluminum plate for heat removal. In the industrial processing, the quality of the thermal dissipation was decided by the gumming technique between the PCB and aluminum plate. In this study, we made the ceramic thin films of diamond like carbon (DLC) by vacuum sputtering between the substrate and high power light emitting diodes (HPLED) light to check the influence of heat transfer by DLC thin films. The ceramic dielectric coatings were characterized by several subsequent analyses, especially the measurement of real work temperature of HPLEDs. The X-Ray photoelectron spectroscopy (XPS) patterns revealed that ceramic phases were successfully grown onto the substrate. At the same time, the real work temperatures showed the thickness of DLC thin film coating effectively affected the thermal conduction of HPLEDs.

ANL ITER high-heat-flux blanket-module heat transfer experiments

International Nuclear Information System (INIS)

Kasza, K.E.

1992-02-01

An Argonne National Laboratory facility for conducting tests on multilayered slab models of fusion blanket designs is being developed; some of its features are described. This facility will allow testing under prototypic high heat fluxes, high temperatures, thermal gradients, and variable mechanical loadings in a helium gas environment. Steady and transient heat flux tests are possible. Electrical heating by a two-sided, thin stainless steel (SS) plate electrical resistance heater and SS water-cooled cold panels placed symmetrically on both sides of the heater allow achievement of global one-dimensional heat transfer across blanket specimen layers sandwiched between the hot and cold plates. The heat transfer characteristics at interfaces, as well as macroscale and microscale thermomechanical interactions between layers, can be studied in support of the ITER engineering design effort. The engineering design of the test apparatus has shown that it is important to use multidimensional thermomechanical analysis of sandwich-type composites to adequately analyze heat transfer. This fact will also be true for the engineering design of ITER

Sorptive thin film microextraction followed by direct solid state spectrofluorimetry: A simple, rapid and sensitive method for determination of carvedilol in human plasma.

Science.gov (United States)

Karimi, Shima; Talebpour, Zahra; Adib, Noushin

2016-06-14

A poly acrylate-ethylene glycol (PA-EG) thin film is introduced for the first time as a novel polar sorbent for sorptive extraction method coupled directly to solid-state spectrofluorimetry without the necessity of a desorption step. The structure, polarity, fluorescence property and extraction performance of the developed thin film were investigated systematically. Carvedilol was used as the model analyte to evaluate the proposed method. The entire procedure involved one-step extraction of carvedilol from plasma using PA-EG thin film sorptive phase without protein precipitation. Extraction variables were studied in order to establish the best experimental conditions. Optimum extraction conditions were the followings: stirring speed of 1000 rpm, pH of 6.8, extraction temperature of 60 °C, and extraction time of 60 min. Under optimal conditions, extraction of carvedilol was carried out in spiked human plasma; and the linear range of calibration curve was 15-300 ng mL(-1) with regression coefficient of 0.998. Limit of detection (LOD) for the method was 4.5 ng mL(-1). The intra- and inter-day accuracy and precision of the proposed method were evaluated in plasma sample spiked with three concentration levels of carvedilol; yielding a recovery of 91-112% and relative standard deviation of less than 8%, respectively. The established procedure was successfully applied for quantification of carvedilol in plasma sample of a volunteer patient. The developed PA-EG thin film sorptive phase followed by solid-state spectrofluorimetric method provides a simple, rapid and sensitive approach for the analysis of carvedilol in human plasma. Copyright © 2016 Elsevier B.V. All rights reserved.

Thin-plate spline analysis of treatment effects of rapid maxillary expansion and face mask therapy in early Class III malocclusions.

Science.gov (United States)

Baccetti, T; Franchi, L; McNamara, J A

1999-06-01

An effective morphometric method (thin-plate spline analysis) was applied to evaluate shape changes in the craniofacial configuration of a sample of 23 children with Class III malocclusions in the early mixed dentition treated with rapid maxillary expansion and face mask therapy, and compared with a sample of 17 children with untreated Class III malocclusions. Significant treatment-induced changes involved both the maxilla and the mandible. Major deformations consisted of forward displacement of the maxillary complex from the pterygoid region and of anterior morphogenetic rotation of the mandible, due to a significant upward and forward direction of growth of the mandibular condyle. Significant differences in size changes due to reduced increments in mandibular dimensions were associated with significant shape changes in the treated group.

Single phase flow pressure drop and heat transfer in rectangular metallic microchannels

International Nuclear Information System (INIS)

Sahar, Amirah M.; Özdemir, Mehmed R.; Fayyadh, Ekhlas M.; Wissink, Jan; Mahmoud, Mohamed M.; Karayiannis, Tassos G.

2016-01-01

Numerical simulations were performed using Fluent 14.5 to investigate single phase flow and conjugate heat transfer in copper rectangular microchannels. Two different configurations were simulated: (1) single channel with hydraulic diameter of 0.561 mm and (2) multichannel configuration consisting of inlet and outlet manifolds and 25 channels with hydraulic diameter of 0.409 mm. In the single channel configuration, four numerical models were investigated namely, 2D thin-wall, 3D thin-wall (heated from the bottom), 3D thin-wall (three side heated) and 3D full conjugate models. In the multichannel configuration, only 3D full conjugate model was used. The simulation results of the single channel configuration were validated using experimental data of water as a test fluid while the results of the multichannel configuration were validated using experimental data of R134a refrigerant. In the multichannel configuration, flow distribution among the channels was also investigated. The 3D thin-wall model simulation was conducted at thermal boundary conditions similar to those assumed in the experimental data reduction (uniform heat flux) and showed excellent agreement with the experimental data. However, the results of the 3D full conjugate model demonstrated that there is a significant conjugate effect and the heat flux is not uniformly distributed along the channel resulting in significant deviation compared to the experimental data (more than 50%). Also, the results demonstrated that there is a significant difference between the 3D thin-wall and full conjugate models. The simulation of the multichannel configuration with an inlet manifold having gradual decrease in cross sectional area achieved very reasonable uniform flow distribution among the channels which will provide uniform heat transfer rates across the base of the microchannels.

Geometric structure of thin SiO xN y films on Si(100)

Science.gov (United States)

Behrens, K.-M.; Klinkenberg, E.-D.; Finster, J.; Meiwes-Broer, K.-H.

1998-05-01

Thin films of amorphous stoichometric SiO xN y are deposited on radiation-heated Si(100) by rapid thermal low-pressure chemical vapour deposition. We studied the whole range of possible compositions. In order to determine the geometric structure, we used EXAFS and photoelectron spectroscopy. Tetrahedrons constitute the short-range units with a central Si atom connected to N and O. The distribution of the possible tetrahedrons can be described by a mixture of the Random Bonding Model and the Random Mixture Model. For low oxygen contents x/( x+ y)≤0.3, the geometric structure of the film is almost the structure of a-Si 3N 4, with the oxygen preferably on top of Si-N 3 triangles. Higher oxygen contents induce changes in the bond lengths, bond angles and coordination numbers.

Heat transfer enhancement in cross-flow heat exchanger using vortex generator

International Nuclear Information System (INIS)

Yoo, S. Y.; Kwon, H. K.; Kim, B. C.; Park, D. S.; Lee, S. S.

2003-01-01

Fouling is very serious problem in heat exchanger because it rapidly deteriorates the performance of heat exchanger. Cross-flow heat exchanger with vortex generators is developed, which enhance heat transfer and reduce fouling. In the present heat exchanger, shell and baffle are removed from the conventional shell-and-tube heat exchanger. The naphthalene sublimation technique is employed to measure the local heat transfer coefficients. The experiments are performed for single circular tube, staggered array tube bank and in-line array tube bank with and without vortex generators. Local and average Nusselt numbers of single tube and tube bank with vortex generator are investigated and compared to those of without vortex generator

On-Chip Sensing of Thermoelectric Thin Film’s Merit

OpenAIRE

Xiao, Zhigang; Zhu, Xiaoshan

2015-01-01

Thermoelectric thin films have been widely explored for thermal-to-electrical energy conversion or solid-state cooling, because they can remove heat from integrated circuit (IC) chips or micro-electromechanical systems (MEMS) devices without involving any moving mechanical parts. In this paper, we report using silicon diode-based temperature sensors and specific thermoelectric devices to characterize the merit of thermoelectric thin films. The silicon diode temperature sensors and thermoelect...

Large carbon cluster thin film gauges for measuring aerodynamic heat transfer rates in hypersonic shock tunnels

International Nuclear Information System (INIS)

Srinath, S; Reddy, K P J

2015-01-01

Different types of Large Carbon Cluster (LCC) layers are synthesized by a single-step pyrolysis technique at various ratios of precursor mixture. The aim is to develop a fast responsive and stable thermal gauge based on a LCC layer which has relatively good electrical conduction in order to use it in the hypersonic flow field. The thermoelectric property of the LCC layer has been studied. It is found that these carbon clusters are sensitive to temperature changes. Therefore suitable thermal gauges were developed for blunt cone bodies and were tested in hypersonic shock tunnels at a flow Mach number of 6.8 to measure aerodynamic heating. The LCC layer of this thermal gauge encounters high shear forces and a hostile environment for test duration in the range of a millisecond. The results are favorable to use large carbon clusters as a better sensor than a conventional platinum thin film gauge in view of fast responsiveness and stability. (paper)

Can cognitive dissonance methods developed in the West for combatting the ‘thin ideal’ help slow the rapidly increasing prevalence of eating disorders in non-Western cultures?

Science.gov (United States)

Witcomb, Gemma L.; Arcelus, Jon; Chen, Jue

2013-01-01

Summary Eating disorders are common, life-threatening conditions in Western countries, but until relatively recently they were regarded as uncommon in non-Western cultures. However, the prevalence of eating disorders in many of the more affluent non-Western countries is rising rapidly as community members, particularly young women, internalize the ‘thin ideal’ that has been widely promoted by the international media. This review discusses the factors involved in the development of eating disorders in non-Western settings with a particular emphasis on the influences of urbanization, modernization, Westernization, and the resulting changes in women's roles. The cognitive dissonance programs developed in Western countries that have proven successful in countering the negative effects of the thin idea are described and their potential application to East Asia and other non-Western countries are discussed. PMID:24991176

An On-Line Method for Thermal Diffusivity Detection of Thin Films Using Infrared Video

Directory of Open Access Journals (Sweden)

Dong Huilong

2016-03-01

Full Text Available A novel method for thermal diffusivity evolution of thin-film materials with pulsed Gaussian beam and infrared video is reported. Compared with common pulse methods performed in specialized labs, the proposed method implements a rapid on-line measurement without producing the off-centre detection error. Through mathematical deduction of the original heat conduction model, it is discovered that the area s, which is encircled by the maximum temperature curve rTMAX(θ, increases linearly over elapsed time. The thermal diffusivity is acquired from the growth rate of the area s. In this study, the off-centre detection error is avoided by performing the distance regularized level set evolution formulation. The area s was extracted from the binary images of temperature variation rate, without inducing errors from determination of the heat source centre. Thermal diffusivities of three materials, 304 stainless steel, titanium, and zirconium have been measured with the established on-line detection system, and the measurement errors are: −2.26%, −1.07%, and 1.61% respectively.

Impact of thermodynamic properties and heat loss on ignition of transportation fuels in rapid compression machines

KAUST Repository

Ahmed, Ahfaz

2018-01-30

Rapid compression machines (RCM) are extensively used to study autoignition of a wide variety of fuels at engine relevant conditions. Fuels ranging from pure species to full boiling range gasoline and diesel can be studied in an RCM to develop a better understanding of autoignition kinetics in low to intermediate temperature ranges. In an RCM, autoignition is achieved by compressing a fuel/oxidizer mixture to higher pressure and temperature, thereby initiating chemical reactions promoting ignition. During these experiments, the pressure is continuously monitored and is used to deduce significant events such as the end of compression and the onset of ignition. The pressure profile is also used to assess the temperature evolution of the gas mixture with time using the adiabatic core hypothesis and the heat capacity ratio of the gas mixture. In such RCM studies, real transportation fuels containing many components are often represented by simpler surrogate fuels. While simpler surrogates such as primary reference fuels (PRFs) and ternary primary reference fuel (TPRFs) can match research and motor octane number of transportation fuels, they may not accurately replicate thermodynamic properties (including heat capacity ratio). This non-conformity could exhibit significant discrepancies in the end of compression temperature, thereby affecting ignition delay (τign) measurements. Another aspect of RCMs that can affect τign measurement is post compression heat loss, which depends on various RCM parameters including geometry, extent of insulation, pre-heating temperature etc. To, better understand the effects of these non-chemical kinetic parameters on τign, thermodynamic properties of a number of FACE G gasoline surrogates were calculated and simulated in a multi-zone RCM model. The problem was further investigated using a variance based analysis and individual sensitivities were calculated. This study highlights the effects on τign due to thermodynamic properties of

Impact of thermodynamic properties and heat loss on ignition of transportation fuels in rapid compression machines

KAUST Repository

Ahmed, Ahfaz; Hantouche, Mireille; Khurshid, Muneeb; Mohamed, Samah; Nasir, Ehson Fawad; Farooq, Aamir; Roberts, William L.; Knio, Omar; Sarathy, Mani

2018-01-01

Rapid compression machines (RCM) are extensively used to study autoignition of a wide variety of fuels at engine relevant conditions. Fuels ranging from pure species to full boiling range gasoline and diesel can be studied in an RCM to develop a better understanding of autoignition kinetics in low to intermediate temperature ranges. In an RCM, autoignition is achieved by compressing a fuel/oxidizer mixture to higher pressure and temperature, thereby initiating chemical reactions promoting ignition. During these experiments, the pressure is continuously monitored and is used to deduce significant events such as the end of compression and the onset of ignition. The pressure profile is also used to assess the temperature evolution of the gas mixture with time using the adiabatic core hypothesis and the heat capacity ratio of the gas mixture. In such RCM studies, real transportation fuels containing many components are often represented by simpler surrogate fuels. While simpler surrogates such as primary reference fuels (PRFs) and ternary primary reference fuel (TPRFs) can match research and motor octane number of transportation fuels, they may not accurately replicate thermodynamic properties (including heat capacity ratio). This non-conformity could exhibit significant discrepancies in the end of compression temperature, thereby affecting ignition delay (τign) measurements. Another aspect of RCMs that can affect τign measurement is post compression heat loss, which depends on various RCM parameters including geometry, extent of insulation, pre-heating temperature etc. To, better understand the effects of these non-chemical kinetic parameters on τign, thermodynamic properties of a number of FACE G gasoline surrogates were calculated and simulated in a multi-zone RCM model. The problem was further investigated using a variance based analysis and individual sensitivities were calculated. This study highlights the effects on τign due to thermodynamic properties of

New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

NARCIS (Netherlands)

Budding, A.; Vaneker, Thomas H.J.

2013-01-01

In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of

Radiation transmission type pipe wall thinning detection device and measuring instruments utilizing ionizing radiation

International Nuclear Information System (INIS)

Higashi, Yasuhiko

2009-01-01

We developed the device to detect thinning of pipe thorough heat insulation in Power Plant, etc, even while the plant is under operation. It is necessary to test many parts of many pipes for pipe wall thinning management, but it is difficult within a limited time of the routine test. This device consists of detector and radiation source, which can detect the pipe (less than 500 mm in external diameter, less than 50 mm in thickness) with 1.6%-reproducibility (in a few-minutes measurement), based on the attenuation rate. Operation is easy and effective without removing the heat insulation. We will expand this thinning detection system, and contribute the safety of the Plant. (author)

Analysis of heating effect on the process of high deposition rate microcrystalline silicon

International Nuclear Information System (INIS)

Xiao-Dan, Zhang; He, Zhang; Chang-Chun, Wei; Jian, Sun; Guo-Fu, Hou; Shao-Zhen, Xiong; Xin-Hua, Geng; Ying, Zhao

2010-01-01

A possible heating effect on the process of high deposition rate microcrystalline silicon has been studied. It includes the discharge time-accumulating heating effect, discharge power, inter-electrode distance, and total gas flow rate induced heating effect. It is found that the heating effects mentioned above are in some ways quite similar to and in other ways very different from each other. However, all of them will directly or indirectly cause the increase of the substrate surface temperature during the process of depositing microcrystalline silicon thin films, which will affect the properties of the materials with increasing time. This phenomenon is very serious for the high deposition rate of microcrystalline silicon thin films because of the high input power and the relatively small inter-electrode distance needed. Through analysis of the heating effects occurring in the process of depositing microcrystalline silicon, it is proposed that the discharge power and the heating temperature should be as low as possible, and the total gas flow rate and the inter-electrode distance should be suitable so that device-grade high quality deposition rate microcrystalline silicon thin films can be fabricated

Microstructures and Mechanical Properties of Austempering SUS440 Steel Thin Plates

Directory of Open Access Journals (Sweden)

Cheng-Yi Chen

2016-02-01

Full Text Available SUS440 is a high-carbon stainless steel, and its martensite matrix has high heat resistance, high corrosion resistance, and high pressure resistance. It has been widely used in mechanical parts and critical materials. However, the SUS440 martempered matrix has reliability problems in thin plate applications and thus research uses different austempering heat treatments (tempering temperature: 200 °C–400 °C to obtain a matrix containing bainite, retained austenite, martensite, and the M7C3 phase to investigate the relationships between the resulting microstructure and tensile mechanical properties. Experimental data showed that the austempering conditions of the specimen affected the volume fraction of phases and distribution of carbides. After austenitizing heat treatment (1080 °C for 30 min, the austempering of the SUS440 thin plates was carried out at a salt-bath temperature 300 °C for 120 min and water quenching was then used to obtain the bainite matrix with fine carbides, with the resulting material having a higher tensile fracture strength and average hardness (HRA 76 makes it suitable for use as a high-strength thin plate for industrial applications.

Preparation and characterization of ZnO transparent semiconductor thin films by sol-gel method

International Nuclear Information System (INIS)

Tsay, Chien-Yie; Fan, Kai-Shiung; Chen, Sih-Han; Tsai, Chia-Hao

2010-01-01

Transparent semiconductor thin films of zinc oxide (ZnO) were deposited onto alkali-free glass substrates by the sol-gel method and spin-coating technique. In this study, authors investigate the influence of the heating rate of the preheating process (4 or 10 o C/min) on the crystallization, surface morphology, and optical properties of sol-gel derived ZnO thin films. The ZnO sol was synthesized by dissolving zinc acetate dehydrate in ethanol, and then adding monoethanolamine. The as-coated films were preheated at 300 o C for 10 min and annealed at 500 o C for 1 h in air ambiance. Experimental results indicate that the heating rate of the preheating process strongly affected the surface morphology and transparency of ZnO thin film. Specifically, a heating rate of 10 o C/min for the preheating process produces a preferred orientation along the (0 0 2) plane and a high transmittance of 92% at a wavelength of 550 nm. Furthermore, this study reports the fabrication of thin-film transistors (TFTs) with a transparent ZnO active channel layer and evaluates their electrical performance.

Magnetization in permalloy thin films

Indian Academy of Sciences (India)

Thin films of permalloy (Ni80Fe20) were prepared using an Ar+N2 mixture with magnetron ... alloys of Ni and Fe) take an important place. NiFe alloy with a ... room temperature (∼298 K, without intentional heating) on Si(100) substrates. A base pressure of 1×10−6 mbar was achieved prior to the deposition. Three different ...

Thermoelectric Cooling-Aided Bead Geometry Regulation in Wire and Arc-Based Additive Manufacturing of Thin-Walled Structures

Directory of Open Access Journals (Sweden)

Fang Li

2018-01-01

Full Text Available Wire and arc-based additive manufacturing (WAAM is a rapidly developing technology which employs a welding arc to melt metal wire for additive manufacturing purposes. During WAAM of thin-walled structures, as the wall height increases, the heat dissipation to the substrate is slowed down gradually and so is the solidification of the molten pool, leading to variation of the bead geometry. Though gradually reducing the heat input via adjusting the process parameters can alleviate this issue, as suggested by previous studies, it relies on experience to a large extent and inevitably sacrifices the deposition rate because the wire feed rate is directly coupled with the heat input. This study introduces for the first time an in-process active cooling system based on thermoelectric cooling technology into WAAM, which aims to eliminate the difference in heat dissipation between upper and lower layers. The case study shows that, with the aid of thermoelectric cooling, the bead width error is reduced by 56.8%, the total fabrication time is reduced by 60.9%, and the average grain size is refined by 25%. The proposed technique provides new insight into bead geometry regulation during WAAM with various benefits in terms of geometric accuracy, productivity, and microstructure.

Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing

KAUST Repository

Wang, N.; Komvopoulos, K.; Rose, F.; Marchon, B.

2013-01-01

Ultrathin amorphous carbon (a-C) films are extensively used as protective overcoats of magnetic recording media. Increasing demands for even higher storage densities have necessitated the development of new storage technologies, such as heat-assisted magnetic recording (HAMR), which uses laser-assisted heating to record data on high-stability media that can store single bits in extremely small areas (∼1 Tbit/in.2). Because HAMR relies on locally changing the coercivity of the magnetic medium by raising the temperature above the Curie temperature for data to be stored by the magnetic write field, it raises a concern about the structural stability of the ultrathin a-C film. In this study, rapid thermal annealing (RTA) experiments were performed to examine the thermal stability of ultrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition. Structural changes in the a-C:H films caused by RTA were investigated by x-ray photoelectron spectroscopy, Raman spectroscopy, x-ray reflectivity, and conductive atomic force microscopy. The results show that the films exhibit thermal stability up to a maximum temperature in the range of 400-450 °C. Heating above this critical temperature leads to hydrogen depletion and sp 2 clustering. The critical temperature determined by the results of this study represents an upper bound of the temperature rise due to laser heating in HAMR hard-disk drives and the Curie temperature of magnetic materials used in HAMR hard disks. © 2013 American Institute of Physics.

Performance Characteristics of PTC Elements for an Electric Vehicle Heating System

Directory of Open Access Journals (Sweden)

Yoon Hyuk Shin

2016-10-01

Full Text Available A high-voltage positive temperature coefficient (PTC heater has a simple structure and a swift response. Therefore, for cabin heating in electric vehicles (EVs, such heaters are used either on their own or with a heat pump system. In this study, the sintering process in the manufacturing of PTC elements for an EV heating system was improved to enhance surface uniformity. The electrode production process entailing thin-film sputtering deposition was applied to ensure the high heating performance of PTC elements and reduce the electrode thickness. The allowable voltage and surface heat temperature of the high-voltage PTC elements with thin-film electrodes were 800 V and 172 °C, respectively. The electrode layer thickness was uniform at approximately 3.8 μm or less, approximately 69% less electrode materials were required compared to that before process improvement. Furthermore, a heater for the EV heating system was manufactured using the developed high-voltage PTC elements to verify performance and reliability.

Alloying process of sputter-deposited Ti/Ni multilayer thin films

International Nuclear Information System (INIS)

Cho, H.; Kim, H.Y.; Miyazaki, S.

2006-01-01

Alloying process of a Ti/Ni multilayer thin film was investigated in detail by differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The Ti/Ni multilayer thin film was prepared by depositing Ti and Ni layers alternately on a SiO 2 /Si substrate. The number of each metal layer was 100, and the total thickness was 3 μm. The alloy composition was determined as Ti-51 at.%Ni by electron probe micro analysis (EPMA). The DSC curve exhibited three exothermic peaks at 621, 680 and 701 K during heating the as-sputtered multilayer thin film. In order to investigate the alloying process, XRD and TEM observation was carried out for the specimens heated up to various temperatures with the heating rate same as the DSC measurement. The XRD profile of the as-sputtered film revealed only diffraction peaks of Ti and Ni. But reaction layers of 3 nm in thickness were observed at the interfaces of Ti and Ni layers in cross-sectional TEM images. The reaction layer was confirmed as an amorphous phase by the nano beam diffraction analysis. The XRD profiles exhibited that the intensity of Ti diffraction peak decreased in the specimen heat-treated above 600 K. The peak from Ni became broad and shifted to lower diffraction angle. The amorphous layer thickened up to 6 nm in the specimen heated up to 640 K. The diffraction peak corresponding to Ti-Ni B2 phase appeared and the peak from Ni disappeared for the specimen heated up to 675 K. The Ti-Ni B2 crystallized from the amorphous reaction layer. After further heating above the third exothermic peak, the intensity of the peak from the Ti-Ni B2 phase increased, the peak from Ti disappeared and the peaks corresponding to Ti 2 Ni appeared. The Ti 2 Ni phase was formed by the reaction of the Ti-Ni B2 and Ti

Manipulation and simulations of thermal field profiles in laser heat-mode lithography

Science.gov (United States)

Wei, Tao; Wei, Jingsong; Wang, Yang; Zhang, Long

2017-12-01

Laser heat-mode lithography is a very useful method for high-speed fabrication of large-area micro/nanostructures. To obtain nanoscale pattern structures, one needs to manipulate the thermal diffusion channels. This work reports the manipulation of the thermal diffusion in laser heat-mode lithography and provides methods to restrain the in-plane thermal diffusion and improve the out-of-plane thermal diffusion. The thermal field profiles in heat-mode resist thin films have been given. It is found that the size of the heat-spot can be decreased by decreasing the thickness of the heat-mode resist thin films, inserting the thermal conduction layers, and shortening the laser irradiation time. The optimized laser writing strategy is also given, where the in-plane thermal diffusion is completely restrained and the out-of-plane thermal diffusion is improved. The heat-spot size is almost equal to that of the laser spot, accordingly. This work provides a very important guide to laser heat-mode lithography.

Rapid, non-destructive and non-contact inspection of solid foods by means of photothermal radiometry; thermal effusivity and initial heating coefficient

Science.gov (United States)

Gijsbertsen, A.; Bicanic, D.; Gielen, J. L. W.; Chirtoc, M.

2004-03-01

CO 2-laser photothermal radiometry (PTR) was demonstrated to be suitable for the non-destructive and non-contact characterization (both optical and thermal) of solid phase agricultural commodities (fresh vegetables, fruits) and confectionery products (candy). Proper interpretation of PTR signals enable one to calculate two parameters, i.e. the well known thermal effusivity e ( e= λρc p, where λ and ρcp are the thermal conductivity and the volume specific heat, respectively) and a newly introduced physical quantity termed 'initial heating coefficient' chi ( χ= β/( ρcp), β is the absorption coefficient). Obtained values for e are in a good agreement with data reported in the literature. PTR enables one to rapidly determine e via a single measurement. As opposed to this, the knowledge of two out of three thermophysical parameters (thermal diffusivity, thermal conductivity and volume specific heat) is a condition sine qua non for determining effusivity in the conventional manner.

Time-resolved plasma spectroscopy of thin foils heated by a relativistic-intensity short-pulse laser

International Nuclear Information System (INIS)

Audebert, P.; Gauthier, J.-C.; Shepherd, R.; Fournier, K.B.; Price, D.; Lee, R.W.; Springer, P.; Peyrusse, O.; Klein, L.

2002-01-01

Time-resolved K-shell x-ray spectra are recorded from sub-100 nm aluminum foils irradiated by 150-fs laser pulses at relativistic intensities of Iλ 2 =2x10 18 W μm 2 /cm 2 . The thermal penetration depth is greater than the foil thickness in these targets so that uniform heating takes place at constant density before hydrodynamic motion occurs. The high-contrast, high-intensity laser pulse, broad spectral band, and short time resolution utilized in this experiment permit a simplified interpretation of the dynamical evolution of the radiating matter. The observed spectrum displays two distinct phases. At early time, ≤500 fs after detecting target emission, a broad quasicontinuous spectral feature with strong satellite emission from multiply excited levels is seen. At a later time, the He-like resonance line emission is dominant. The time-integrated data is in accord with previous studies with time resolution greater than 1 ps. The early time satellite emission is shown to be a signature of an initial large area, high density, low-temperature plasma created in the foil by fast electrons accelerated by the intense radiation field in the laser spot. We conclude that, because of this early time phenomenon and contrary to previous predictions, a short, high-intensity laser pulse incident on a thin foil does not create a uniform hot and dense plasma. The heating mechanism has been studied as a function of foil thickness, laser pulse length, and intensity. In addition, the spectra are found to be in broad agreement with a hydrodynamic expansion code postprocessed by a collisional-radiative model based on superconfiguration average rates and on the unresolved transition array formalism

Synthesis of thin films by the pyrosol process

Directory of Open Access Journals (Sweden)

Tucić Aleksandar

2002-01-01

Full Text Available Among many aerosol routes, the Pyrosol process, due to its simplicity, low cost and quality of obtained films, represents a promising technique for the synthesis of thin films. The pyrosol process is based on the transport and pyrolysls of an aerosol of processor solution, generated in an ultrasonic atomizer, on a heated substrate. The theoretical principles of the pyrosol process are presented in this paper, as well as the influence of some synthesis parameters on the deposition of SnO2 thin films.

Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

International Nuclear Information System (INIS)

Zhu Nai-Wei; Hu Ming; Xia Xiao-Xu; Wei Xiao-Ying; Liang Ji-Ran

2014-01-01

The VO 2 thin film with high performance of metal–insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO 2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO 2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO 2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively. (interdisciplinary physics and related areas of science and technology)

Heat Generation by Irradiated Complex Composite Nanostructures

DEFF Research Database (Denmark)

Ma, Haiyan; Tian, Pengfei; Pello, Josselin

2014-01-01

Heating of irradiated metallic e-beam generated nanostructures was quantified through direct measurements paralleled by novel model-based numerical calculations. By comparing discs, triangles, and stars we showed how particle shape and composition determines the heating. Importantly, our results...... revealed that substantial heat is generated in the titanium adhesive layer between gold and glass. Even when the Ti layer is as thin as 2 nm it absorbs as much as a 30 nm Au layer and hence should not be ignored....

Transformation Heat Treatment of Rapidly Quenched Nb3A1 Precursor Monitored in situ by High Energy Synchrotron Diffraction

CERN Document Server

Scheuerlein, C; Di Michiel, M; Jin, X; Takeuchi, T; Kikuchi, A; Tsuchiya, K; Nakagawa, K; Nakamoto, T

2013-01-01

Nb3Al superconductors are studied for use in high field magnets. Fine grained Nb3Al with nearly stoichiometric Al content is obtained by a Rapid Heating Quenching and Transformation (RHQT) process. We describe a non destructive in situ study of the transformation process step of a RHQ Nb3Al precursor wire with ramp rates of either 120 °C/h or 800 °C/h. High energy synchrotron x-ray diffraction measurements show the transformation from a Nb(Al)SS supersaturated solid solution into Nb3Al. When heating with a ramp rate of 120 °C/h a strong reduction of the Nb(Al)SS (110) diffraction peak component is observed when the temperature exceeds 660 °C. Additional diffraction peaks are detectable in the approximate temperature interval 610 °C - 750 °C and significant Nb3Al growth is observed above 730 °C.

Feasibility Study of Thin Film Thermocouple Piles

Science.gov (United States)

Sisk, R. C.

2001-01-01

Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

Heat waves imposed during early pod development in soybean (Glycine max) cause significant yield loss despite a rapid recovery from oxidative stress.

Science.gov (United States)

Siebers, Matthew H; Yendrek, Craig R; Drag, David; Locke, Anna M; Rios Acosta, Lorena; Leakey, Andrew D B; Ainsworth, Elizabeth A; Bernacchi, Carl J; Ort, Donald R

2015-08-01

Heat waves already have a large impact on crops and are predicted to become more intense and more frequent in the future. In this study, heat waves were imposed on soybean using infrared heating technology in a fully open-air field experiment. Five separate heat waves were applied to field-grown soybean (Glycine max) in central Illinois, three in 2010 and two in 2011. Thirty years of historical weather data from Illinois were analyzed to determine the length and intensity of a regionally realistic heat wave resulting in experimental heat wave treatments during which day and night canopy temperatures were elevated 6 °C above ambient for 3 days. Heat waves were applied during early or late reproductive stages to determine whether and when heat waves had an impact on carbon metabolism and seed yield. By the third day of each heat wave, net photosynthesis (A), specific leaf weight (SLW), and leaf total nonstructural carbohydrate concentration (TNC) were decreased, while leaf oxidative stress was increased. However, A, SLW, TNC, and measures of oxidative stress were no different than the control ca. 12 h after the heat waves ended, indicating rapid physiological recovery from the high-temperature stress. That end of season seed yield was reduced (~10%) only when heat waves were applied during early pod developmental stages indicates the yield loss had more to do with direct impacts of the heat waves on reproductive process than on photosynthesis. Soybean was unable to mitigate yield loss after heat waves given during late reproductive stages. This study shows that short high-temperature stress events that reduce photosynthesis and increase oxidative stress resulted in significant losses to soybean production in the Midwest, U.S. The study also suggests that to mitigate heat wave-induced yield loss, soybean needs improved reproductive and photosynthetic tolerance to high but increasingly common temperatures. Published 2015. This article is a U.S. Government work and is

Magnetic and magneto-optical properties of FeRh thin films

International Nuclear Information System (INIS)

Inoue, Sho; Nam, Nguyen T.; Phuoc, Nguyen N.; Cao Jiangwei; Yu Ko, Hnin Yu; Suzuki, Takao

2008-01-01

The magnetic and magneto-optical properties of FeRh thin films epitaxially deposited onto MgO(1 0 0) substrates by RF sputter-deposition system have been investigated in conjunction with the structure. An intriguing virgin effect has been found in the M-T curves of the as-deposited FeRh thin films, which is presumably interpreted in term of a change in structural phase when heating. Also, a (negative) maximum peak of Kerr rotation at around 3.8 eV has been observed when FeRh thin films are in ferromagnetic state. The polar Kerr rotation angle is found to increase at temperatures above 100 deg. C, which corresponds to the antiferromagnet (AF)-ferromagnet (FM) transition of FeRh thin films

Crystallization of sol-gel derived lead zirconate titanate thin films in argon and oxygen atmospheres

International Nuclear Information System (INIS)

Bursill, L.A.

1994-01-01

Electron diffraction and high-resolution electron microscopic techniques are applied to reveal the mechanisms of crystallization of 75 nm thin films of ferroelectric lead-zirconate-titanate (PZT). Sol-gel methods, followed by pyrolysis at 350 deg C, were used to provide a common starting point after which a variety of rapid-thermal annealing (RTA) experiments in the temperature range 400-700 deg C were made in argon, oxygen and nitrogen/hydrogen atmospheres. The results are interpreted in terms of the crystal chemical analysis, which points out that partial pressure of oxygen and heating rate are important experimental parameters which must be controlled if ferroelectric perovskite-type Pb 2 ZrTiO 6 , rather than pyrochlore-type Pb 2 ZrTiO 6+x , where O < X < 1 or -1 < X < O, is to be obtained after the RTA step. Thus significant improvements in the crystallization of perovskite-type PZT were clearly demonstrated by using argon atmospheres for the RTA step. The results have significance for the production of high-quality ferroelectric thin films, with improved switching and fatigue characteristics, since even small amounts of the pyrochlore phase prove detrimental for these properties. 18 refs., 1 tab., 10 figs

Heat insulation support device

International Nuclear Information System (INIS)

Takahashi, Hiroyuki; Koda, Tomokazu; Motojima, Osamu; Yamamoto, Junya.

1994-01-01

The device of the present invention comprises a plurality of heat insulation legs disposed in a circumferential direction. Each of the heat insulative support legs has a hollow shape, and comprises an outer column and an inner column as support structures having a heat insulative property (heat insulative structure), and a thermal anchor which absorbs compulsory displacement by a thin flat plate (displacement absorber). The outer column, the thermal anchor and the inner column are connected by a support so as to offset the positional change of objects to be supported due to shrinkage when they are shrunk. In addition, the portion between the superconductive coils as the objects to be supported and the inner column is connected by the support. The superconductive thermonuclear device is entirely contained in a heat insulative vacuum vessel, and the heat insulative support legs are disposed on a lower lid of the heat insulative vacuum vessel. With such a constitution, they are strengthened against lateral load and buckling, thereby enabling to reduce the amount of heat intrusion while keeping the compulsory displacement easy to be absorbed. (I.N.)

DLC and AlN thin films influence the thermal conduction of HPLED light

Science.gov (United States)

Hsu, Ming Seng; Hsu, Ching Yao; Huang, Jen Wei; Shyu, Feng Lin

2015-08-01

Thermal dissipation had an important influence in the effect and life of light emitting diodes (LED) because it enables transfer the heat away from electric device to the aluminum plate that can be used for heat removal. In the industrial processing, the quality of the thermal dissipation decides by the gumming technique between the PCB and aluminum plate. In this study, we fabricated double layer ceramic thin films of diamond like carbon (DLC) and alumina nitride (AlN) by vacuum sputtering soldered the substrate of high power light emitting diodes (HPLED) light to check the heat conduction. The ceramic dielectric coatings were characterized by several subsequent analyses, especially the measurement of real work temperature. The X-Ray photoelectron spectroscopy (XPS) patterns reveal those ceramic phases were successfully grown onto the substrate. The work temperatures show DLC and AlN films coating had limited the heat transfer by the lower thermal conductivity of these ceramic films. Obviously, it hadn't transferred heat and limited work temperature of HPLED better than DLC thin film only.

Platinum containing amorphous hydrogenated carbon (a-C:H/Pt) thin films as selective solar absorbers

International Nuclear Information System (INIS)

Lan, Yung-Hsiang; Brahma, Sanjaya; Tzeng, Y.H.; Ting, Jyh-Ming

2014-01-01

We have investigated a double-cermet structured thin film in which an a-C:H thin film was used as an anti-reflective (AR) layer and two platinum-containing amorphous hydrogenated carbon (a-C:H/Pt) thin films were used as the double cermet layers. A reactive co-sputter deposition method was used to prepare both the anti-reflective and cermet layers. Effects of the target power and heat treatment were studied. The obtained films were characterized using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy. The optical absorptance and emittance of the as deposited and annealed films were determined using UV–vis-NIR spectroscopy. We show that the optical absorptance of the resulting double-cermet structured thin film is as high as 96% and remains to be 91% after heat treatment at 400 °C, indicating the thermal stability of the film

Investigation of the correlation between dielectric function, thickness and morphology of nano-granular ZnO very thin films

Energy Technology Data Exchange (ETDEWEB)

Gilliot, Mickaël, E-mail: mickael.gilliot@univ-reims.fr [Laboratoire d' Ingénierie et Sciences des Matériaux, Université de Reims Champagne-Ardenne (France); Hadjadj, Aomar [Laboratoire d' Ingénierie et Sciences des Matériaux, Université de Reims Champagne-Ardenne (France); Martin, Jérôme [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Université de Technologie de Troyes (France)

2015-12-31

Thin nano-granular ZnO layers were prepared using a sol–gel synthesis and spin-coating deposition process with a thickness ranging between 20 and 120 nm. The complex dielectric function (ϵ) of the ZnO film was determined from spectroscopic ellipsometry measurements. Up to a critical thickness close to 60 nm, the magnitude of both the real and the imaginary parts of ϵ rapidly increases and then slowly tends to values closer to the bulk ZnO material. This trend suggests a drastic change in the film porosity at both sides of this critical thickness, due to the pre-heating and post-crystallization processes, as confirmed by additional characterization of the structure and the morphology of the ZnO films. - Highlights: • c-Axis oriented ZnO thin films were grown with different morphological states. • The morphology and structures are controlled by controlling the thickness. • The optical properties are correlated to morphological evolution. • Two growth behaviors and property evolutions are identified around a critical thickness.

Ocean disposal of heat generating radioactive waste

International Nuclear Information System (INIS)

1986-03-01

The objective of this study was to predict tensile stress levels in thin-walled titanium alloy and thick-walled carbon steel containers designed for the ocean disposal of heat-generating radioactive wastes. Results showed that tensile stresses would be produced in both designs by the expansion of the lead filter, for a temperature rise of 200 0 C. Tensile stress could be reduced if the waste heat output at disposal was reduced. Initial stresses for the titanium-alloy containers could be relieved by heat treatment. (UK)

Self-consistent viscous heating of rapidly compressed turbulence

Science.gov (United States)

Campos, Alejandro; Morgan, Brandon

2017-11-01

Given turbulence subjected to infinitely rapid deformations, linear terms representing interactions between the mean flow and the turbulence dictate the evolution of the flow, whereas non-linear terms corresponding to turbulence-turbulence interactions are safely ignored. For rapidly deformed flows where the turbulence Reynolds number is not sufficiently large, viscous effects can't be neglected and tend to play a prominent role, as shown in the study of Davidovits & Fisch (2016). For such a case, the rapid increase of viscosity in a plasma-as compared to the weaker scaling of viscosity in a fluid-leads to the sudden viscous dissipation of turbulent kinetic energy. As shown in Davidovits & Fisch, increases in temperature caused by the direct compression of the plasma drive sufficiently large values of viscosity. We report on numerical simulations of turbulence where the increase in temperature is the result of both the direct compression (an inviscid mechanism) and the self-consistent viscous transfer of energy from the turbulent scales towards the thermal energy. A comparison between implicit large-eddy simulations against well-resolved direct numerical simulations is included to asses the effect of the numerical and subgrid-scale dissipation on the self-consistent viscous This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Soft chemistry routes to transparent metal oxide thin films. The case of sol–gel synthesis and structural characterization of Ta2O5 thin films from tantalum chloromethoxide

International Nuclear Information System (INIS)

Epifani, Mauro; Zamani, Reza; Arbiol, Jordi; Fabrega, Cristian; Andreu, Teresa; Pace, Giovanni Battista; Siciliano, Pietro; Morante, Joan R.

2014-01-01

Ta 2 O 5 thin films were prepared by spin-coating methanol solutions of Ta chloromethoxide. It was prepared by reacting TaCl 5 with methanol, followed by water addition (H 2 O: Ta molar ratio was 16). Thin films were deposited by spin-coating onto SiO 2 /Si substrates, followed by drying at 90 °C and heat-treatment up to 700 °C. The films were characterized by X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. Crystallization was obtained only after heating at 700 °C, in the Ta 2 O 5 orthorhombic phase. The resulting films had a thickness of 100 nm. Their structure was constituted by porous crystals with size up to 50 nm, while the pores had a size of about 10 nm. The results demonstrated that TaCl 5 is very convenient precursor for the wet chemical synthesis of Ta 2 O 5 thin films. - Highlights: • Development of convenient solution synthesis of Ta 2 O 5 thin films; • The precursor chemistry was established and related to the synthesis process; • Uniform films crystallized in the most stable orthorombic Ta 2 O 5 phase;

Vibration welding system with thin film sensor

Science.gov (United States)

Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

2014-03-18

A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

Radial flow heat exchanger

Science.gov (United States)

Valenzuela, Javier

2001-01-01

A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

Development of Falling Film Heat Transfer Coefficient for Industrial Chemical Processes Evaporator Design

KAUST Repository

Shahzad, Muhammad Wakil

2018-03-07

In falling film evaporators, the overall heat transfer coefficient is controlled by film thickness, velocity, liquid properties and the temperature differential across the film layer. This chapter presents the heat transfer behaviour for evaporative film boiling on horizontal tubes, but working at low pressures of 0.93–3.60 kPa as well as seawater salinity of 15,000–90,000 mg/l or ppm. Owing to a dearth of literature on film-boiling at these conditions, the chapter is motivated by the importance of evaporative film-boiling in the process industries. It is observed that in addition to the above-mentioned parameters, evaporative heat transfer of seawater is affected by the emergence of micro-bubbles within the thin film layer, particularly when the liquid saturation temperatures drop below 25°C (3.1 kPa). Such micro-bubbles are generated near to the tube wall surfaces, and they enhanced the heat transfer by two or more folds when compared with the predictions of conventional evaporative film-boiling. The appearance of micro-bubbles is attributed to the rapid increase in the specific volume of vapour, i.e. dv/dT, at low saturation temperature conditions. A new correlation is thus proposed in this chapter and it shows good agreement to the measured data with an experimental uncertainty less than ±8%.

Thin-layer chromatographic technique for rapid detection of bacterial phospholipases.

Science.gov (United States)

Legakis, N J; Papavassiliou, J

1975-11-01

Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.

Tank wall thinning -- Process and programs

International Nuclear Information System (INIS)

Greer, S.D.; McBrine, W.J.

1994-01-01

In-service thinning of tank walls has occurred in the power industry and can pose a significant risk to plant safety and dependability. Appropriate respect for the energy stored in a high-pressure drain tank warrants a careful consideration of this possibility and appropriate action in order to assure the adequate safety margins against leakage or rupture. Although it has not proven to be a widespread problem, several cases of wall thinning and at least one recent tank rupture has highlighted this issue in recent years, particularly in nuclear power plants. However, the problem is not new or unique to the nuclear power industry. Severe wall thinning in deaerator tanks has been frequently identified at fossil-fueled power plants. There are many mechanisms which can contribute to tank wall thinning. Considerations for a specific tank are dictated by the system operating conditions, tank geometry, and construction material. Thinning mechanisms which have been identified include: Erosion/Corrosion Impingement Erosion Cavitation Erosion General Corrosion Galvanic Corrosion Microbial-induced Corrosion of course there are many other possible types of material degradation, many of which are characterized by pitting and cracking. This paper specifically addresses wall thinning induced by Erosion/Corrosion (also called Flow-Accelerated Corrosion) and Impingement Erosion of tanks in a power plant steam cycle. Many of the considerations presented are applicable to other types of vessels, such as moisture separators and heat exchangers

Perovskite phase thin films and method of making

Science.gov (United States)

Boyle, Timothy J.; Rodriguez, Mark A.

2000-01-01

The present invention comprises perovskite-phase thin films, of the general formula A.sub.x B.sub.y O.sub.3 on a substrate, wherein A is selected from beryllium, magnesium, calcium, strontium, and barium or a combination thereof; B is selected from niobium and tantalum or a combination thereof; and x and y are mole fractions between approximately 0.8 and 1.2. More particularly, A is strontium or barium or a combination thereof and B is niobium or tantalum or a combination thereof. Also provided is a method of making a perovskite-phase thin film, comprising combining at least one element-A-containing compound, wherein A is selected from beryllium, magnesium, calcium, strontium or barium, with at least one element-B-containing compound, wherein B niobium or tantalum, to form a solution; adding a solvent to said solution to form another solution; spin-coating the solution onto a substrate to form a thin film; and heating the film to form the perovskite-phase thin film.

Nanofluid application: liquid sublayer structure and heat transfer mechanism

International Nuclear Information System (INIS)

Bang, In Cheol; Chang, Soon Heung

2005-01-01

Boiling has important modern applications for macroscopic heat transfer exchangers, such as those in nuclear and fossil power plants, and for microscopic heat transfer devices, such as heat pipes and microchannels for cooling electronic chips. The use of boiling is limited by critical heat flux which is characterized by both its highest efficient heat transport capability and the initiation of surface damage caused by suddenly deteriorating heat transfer. For instance, damage can be directly related to the physical burnout of the materials of a heat exchanger. However, the physical mechanism of this limitation has not been understood clearly. In relation to the mechanisms, there is a general consensus that fully developed nucleate boiling on a heated solid surface is characterized by the existence of a liquid film on the heated solid surface. The occurrence of the boiling limitation, the so-called critical heat flux (CHF) has been linked closely to the behavior of the liquid film. This liquid film is generally referred to as the 'thin liquid layer' or the 'macrolayer' to distinguish it from the microlayer that exists under the base of discrete nucleating bubbles. The question to be answered is whether a stable thin liquid layer under a vapor boiling environment could actually exist. If so, what precisely is the role of such a liquid film in relation to the boiling limitation? Reliable answers will depend on direct experimental observations. Currently, there has been no direct observation of the liquid layer. Numerous subsequent studies have failed to provide a direct confirmation of a stable thin liquid layer under a vapor boiling environment. In 1977, Yu and Mesler offered a hypothesis of the existence of the layer, as illustrated in Figure 1. Katto and Yokoya demonstrated the importance of Yu and Mesler's hypothesis; they used it to show that it is possible to approach the very complicated boiling limitation phenomenon with a relatively simple liquid layer

MINIVER: Miniature version of real/ideal gas aero-heating and ablation computer program

Science.gov (United States)

Hendler, D. R.

1976-01-01

Computer code is used to determine heat transfer multiplication factors, special flow field simulation techniques, different heat transfer methods, different transition criteria, crossflow simulation, and more efficient thin skin thickness optimization procedure.

Experimental investigation of thermal loading of a horizontal thin plate using infrared camera

Directory of Open Access Journals (Sweden)

M.Y. Abdollahzadeh Jamalabadi

2014-07-01

Full Text Available This study reports the results of experimental investigations of the characteristics of thermal loading of a thin plate by discrete radiative heat sources. The carbon–steel thin plate is horizontally located above the heat sources. Temperature distribution of the plate is measured using an infrared camera. The effects of various parameters, such as the Rayleigh number, from 107 to 1011, the aspect ratio, from 0.05 to 0.2, the distance ratio, from 0.05 to 0.2, the number of heaters, from 1 to 24, the thickness ratio, from 0.003 to 0.005, and the thermal radiative emissivity, from 0.567 to 0.889 on the maximum temperature and the length of uniform temperature region on a thin plate are explored. The results indicate that the most effective parameters on the order of impact on the maximum temperature is Rayleigh number, the number of heat sources, the distance ratio, the aspect ratio, the surface emissivity, and the plate thickness ratio. Finally, the results demonstrated that there is an optimal distance ratio to maximize the region of uniform temperature on the plate.

The structural design of the experimental equipment for unconventional heating water using heat transfer surfaces located in the heat source

Directory of Open Access Journals (Sweden)

Jandačka J.

2013-04-01

Full Text Available Flue gas temperature at throat of most industrially produced fireplaces is around 250 to 350 °C. It's quite interesting thermal potential, which can be even before sucking up the chimney back utilize. One of the potential uses of this device to heat the hot water. Article refers to the structural design of such a device, which works with the transfer of heat through a substance changes phase from liquid to steam in a sealed tube (heat pipe. Benefits of heat pipes is their light weight, the thermal effect of a rapid and low maintenance costs.

The structural design of the experimental equipment for unconventional heating water using heat transfer surfaces located in the heat source

Science.gov (United States)

Kaduchová, K.; Lenhard, R.; Gavlas, S.; Jandačka, J.

2013-04-01

Flue gas temperature at throat of most industrially produced fireplaces is around 250 to 350 °C. It's quite interesting thermal potential, which can be even before sucking up the chimney back utilize. One of the potential uses of this device to heat the hot water. Article refers to the structural design of such a device, which works with the transfer of heat through a substance changes phase from liquid to steam in a sealed tube (heat pipe). Benefits of heat pipes is their light weight, the thermal effect of a rapid and low maintenance costs.

Thin-film antifuses for pellistor type gas sensors

NARCIS (Netherlands)

Kovalgin, Alexeij Y.; Holleman, J.; van den Berg, Albert; Wallinga, Hans

2001-01-01

This work extends our previously reported idea of using the nano-scale conductive link (antifuse) as a combined heating /detecting element in a Pellistor-type gas sensor. Our new thin-film antifuse is designed in such a way that the oxide, for minimising the bulk influence on surface temperature,

Optimisation of chemical solution deposition of indium tin oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Sunde, Tor Olav Løveng; Einarsrud, Mari-Ann; Grande, Tor, E-mail: grande@ntnu.no

2014-12-31

An environmentally friendly aqueous sol–gel process has been optimised to deposit indium tin oxide (ITO) thin films, aiming to improve the film properties and reduce the deposition costs. It was demonstrated how parameters such as cation concentration and viscosity could be applied to modify the physical properties of the sol and thereby reduce the need for multiple coatings to yield films with sufficient conductivity. The conductivity of the thin films was enhanced by adjusting the heat treatment temperature and atmosphere. Both increasing the heat treatment temperature of the films from 530 to 800 °C and annealing in reducing atmosphere significantly improved the electrical conductivity, and conductivities close to the state of the art sputtered ITO films were obtained. A pronounced decreased conductivity was observed after exposing the thin films to air and the thermal reduction and ageing of the film was studied by in situ conductivity measurements. - Highlights: • Spin coating of indium tin oxide using an aqueous solution was optimised. • The conductivity was enhanced by thermal annealing in reducing atmosphere. • The conductivity of is comparable to the conductivity of sputtered films. • A relaxation process in the reduced thin film was observed after exposure in air.

Investigation of ultrafast lattice heating in thin (semi-)metal films using time-resolved electron diffraction; Untersuchung der schnellen Gitteraufheizung in duennen (Halb-)Metallfilmen mit Hilfe zeitaufgeloester Elektronenbeugung

Energy Technology Data Exchange (ETDEWEB)

Ligges, Manuel

2009-07-21

In the framework of the present thesis the fast lattice heating in thin metal and bismuth layers after optical short-pulse excitation was studied. By irradiation of ultrathin solid films with ultrashort (femtosecond) laser pulses for sort times an extreme nonequilibrium state occurs: The electronic system is strongly excited, while the lattice system remains cold. An energetic exchange between both systems follows, which is based on the electron-phonon interaction and leads to heating of the lattice system. This lattice heating can be observed by means of the Debye-Waller effect in the electron diffraction image. By means of the excitation-interrogation scheme by a series of moment records this lattice heating can be observed time-resolvedly. The experimentally determind time scales for this process permit conclusions on the electron-phonon coupling in the studied materials. In this thesis a time-resolving transmissi9on-electron diffraction experiment with sub-picosecond time resolution was constructed and optimized. By means of this experiment the fast lattice heating in thin gold, silver, copper, and bismuth films was studied. The observed heating behaviour of the metal films shows agreement with theoretical predictions of different model calculations. The results of the measurements on bismuth films show a hitherto not observed coupling behaviour. [German] Im Rahmen der vorliegenden Arbeit wurde die schnelle Gitteraufheizung in duennen Metall- und Wismutschichten nach optischer Kurzimpulsanregung untersucht. Durch Bestrahlung duenner Festkoerperfilme mit ultrakurzen (Femtosekunden-) Laserimpulsen entsteht fuer kurze Zeiten ein extremer Nichtgleichgewichtszustand: Das elektronische System wird stark angeregt, waehrend das Gittersystem kalt bleibt. Es folgt ein energetischer Austausch zwischen beiden Systemen, der auf der Elektron-Phonon-Wechselwirkung beruht und zur Aufheizung des Gittersystems fuehrt. Diese Gitteraufheizung kann anhand des Debye

The effects of heat treatment on optical, structural, electrochromic and bonding properties of Nb{sub 2}O{sub 5} thin films

Energy Technology Data Exchange (ETDEWEB)

Coşkun, Özlem Duyar, E-mail: duyar@hacettepe.edu.tr [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey); Demirel, Selen, E-mail: nymph24@gmail.com [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey); Hacettepe University, Nanotechnology and Nanomedicine Department, Ankara (Turkey); Atak, Gamze, E-mail: gbaser@hacettepe.edu.tr [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey)

2015-11-05

Nb{sub 2}O{sub 5} thin films were deposited onto heated glass substrates by RF magnetron sputtering using a Nb{sub 2}O{sub 5} target. The films were annealed in air at temperatures between 400 and 700 °C for 6 h. Effects of the crystalline structure on optical, structural, electrochromic and bonding properties of the Nb{sub 2}O{sub 5} thin films were investigated by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, optical spectrophotometry and electrochemical measurements. The film refractive index varied between 2.09 and 2.22 at the wavelength of 550 nm depending on the annealing temperature. The decrease of the optical band gap revealed for the films with increasing annealing temperature is attributed to oxygen-ion vacancies in the film structure. The orthorhombic structure of Nb{sub 2}O{sub 5} films resulted in good electrochromic properties with high colouration efficiencies of 19.56 cm{sup 2}/C and 53.24 cm{sup 2}/C at 550 nm and 1000 nm, respectively. The optical, structural and electrochromic properties of the different crystalline polymorphic forms of the Nb{sub 2}O{sub 5} films make them attractive for optical applications. - Highlights: • Stoichiometric Nb{sub 2}O{sub 5} films prepared using RF magnetron sputtering technique. • The different crystalline forms of Nb{sub 2}O{sub 5} thin films obtained by annealing. • The optical, structural and electrochromic properties of the films were investigated. • The optical band gap decreased with increasing annealing temperature. • The orthorhombic T-Nb{sub 2}O{sub 5} films exhibited a higher colouration efficiency.

Heat transfer characteristics of the two-phase closed thermosyphon (wickless heat pipe)

International Nuclear Information System (INIS)

Andros, F.E.; Florschuetz, L.W.

1982-01-01

Steady-state heat transfer characteristics and heat transfer limits (dry-out) for a vertical stainless steel tubular two-phase closed thermosyphon with Freon-113 working fluid are reported as a function of certain geometric parameters and liquid fill quantity. Condenser section heat transfer characteristics agreed reasonably well with existing laminar film condensation correlations and were found to be independent of the evaporator section, except for larger liquid fills. Evaporator characteristics were quite complex and appeared, under some conditions, to be coupled to condenser characteristics through effects of system pressure and/or surface wave as present on the descending condensate film. A laminar thin film evaporation model was found to give reasonable agreement with local evaporator temperature measurements in those regions of the evaporator where a continuous film apparently persisted. The measured heat transfer characteristics are interpreted relative to an earlier investigation by the authors in which flow characteristics in a similar device were visually and photographically observed. 10 references

High-intensity, thin-target He-jet production source

International Nuclear Information System (INIS)

Bai, Y.; Vieira, D.J.; Wouters, J.M.; Butler, G.W.; Rosenauer, Dk; Loebner, K.E.G.; Lind, V.G.; Phillips, D.R.

1996-01-01

A thin-target He-jet system suited to the production and rapid transport of non-volatile radioactive species has been successfully operated with proton beam intensities of up to 700 μA. The system consists of a water-cooled, thin-target chamber, capillary gas transport system, moving tape/Ge detection system, and an aerosol generator/gas recirculator. The yields for a wide variety of uranium fission and deep spallation products have been measured and robust operation of the system demonstrated for several weeks. He-jet transport and collection efficiencies ranged between 15 and 25% with collection rates of 10 7 to 10 8 atoms/sec/isotope. The high-intensity, thin-target He-jet approach represents a robust production source for nonvolatile radioactive heavy ion beams

Application of electron accelerator for thin film in Indonesia

International Nuclear Information System (INIS)

Danu, Sugiarto; Darsono, Dadang

2004-01-01

Electron accelerator is widely used for the crosslinking of wire and cable insulation, the treatment of heat shrinkable products, precuring of tire components, and the sterilization of medical products. Research and development the use of electron accelerator for thin film in Indonesia covered radiation curing of surface coating, crosslinking of poly (butylenes succinate), crosslinking of wire, cable and heat shrinkable, sterilization of wound dressing, and prevulcanization of tire. In general, comparing with conventional method, electron beam processing have some advantages, such as, less energy consumption, much higher production rate, processing ability at ambient temperature and environmental friendly. Indonesia has a great potential to develop the application of electron accelerator, due to the remarkable growth industrial sector, the abundant of natural resources and the increasing demand of the high quality products. This paper describes the activities concerning with R and D, and application of electron accelerator for processing of thin film. (author)

Solution-deposited CIGS thin films for ultra-low-cost photovoltaics

Science.gov (United States)

Eldada, Louay A.; Hersh, Peter; Stanbery, Billy J.

2010-09-01

We describe the production of photovoltaic modules with high-quality large-grain copper indium gallium selenide (CIGS) thin films obtained with the unique combination of low-cost ink-based precursors and a reactive transfer printing method. The proprietary metal-organic inks contain a variety of soluble Cu-, In- and Ga- multinary selenide materials; they are called metal-organic decomposition (MOD) precursors, as they are designed to decompose into the desired precursors. Reactive transfer is a two-stage process that produces CIGS through the chemical reaction between two separate precursor films, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage, these precursors are rapidly reacted together under pressure in the presence of heat. The use of two independent thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the synthesis of CIGS. In a few minutes, the process produces high quality CIGS films, with large grains on the order of several microns, and preferred crystallographic orientation, as confirmed by compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 14% and module efficiencies of 12% were achieved using this method. The atmospheric deposition processes include slot die extrusion coating, ultrasonic atomization spraying, pneumatic atomization spraying, inkjet printing, direct writing, and screen printing, and provide low capital equipment cost, low thermal budget, and high throughput.

In situ nanocalorimetry of thin glassy organic films

Science.gov (United States)

León-Gutierrez, E.; Garcia, G.; Lopeandía, A. F.; Fraxedas, J.; Clavaguera-Mora, M. T.; Rodríguez-Viejo, J.

2008-11-01

In this work, we describe the design and first experimental results of a new setup that combines evaporation of liquids in ultrahigh vacuum conditions with in situ high sensitivity thermal characterization of thin films. Organic compounds are deposited from the vapor directly onto a liquid nitrogen cooled substrate, permitting the preparation and characterization of glassy films. The substrate consists of a microfabricated, membrane-based nanocalorimeter that permits in situ measurements of heat capacity under ultrafast heating rates (up to 105 K/s) in the temperature range of 100-300 K. Three glass forming liquids—toluene, methanol, and acetic acid—are characterized. The spikes in heat capacity related to the glass-transition temperature, the fictive temperature and, in some cases, the onset temperature of crystallization are determined for several heating rates.

Morphological changes in polyoxymethylene on heating and cooling

Science.gov (United States)

Guruswamy, K.; Surve, N.; Mathew, R.; Bulakh, N.; Ajithkumar, T.; Rajamohanan, P.; Ratnagiri, R.

2010-03-01

We use modulated DSC, SAXS and solid state NMR to characterize melting, lamellar-level structure and nuclear environments respectively during heating of polyoxymethylene. Two model samples are investigated -- a melt crystallized injection molded sample and a sample obtained by dilute solution crystallization. On heating the molded sample, we observe evidence for pre-melting at temperatures significantly lower than the nominal melting point, and show that this correlates with the melting of thin, imperfect lamellae inserted in-between thicker lamellae. When the temperature is increased from room temperature to around 100^oC, the microstructural changes are essentially reversible on cooling to room temperature. However, on heating to temperatures above 135^oC, melting of the thin lamellae results in irreversible reorganization of the semicrystalline microstructure to form thicker lamellae. In contrast to the behavior of the melt crystallized samples, the solution crystals exhibit no change in the lamellar stacking on heating to 150^oC. With increase in temperature, there is amorphization at the basal surfaces of the lamellae, but the thermal motions of the amorphous chain segments remain highly constrained due to their connectivity to the lamellar surface.

Rapid fabrication of detachable three-dimensional tissues by layering of cell sheets with heating centrifuge.

Science.gov (United States)

Haraguchi, Yuji; Kagawa, Yuki; Hasegawa, Akiyuki; Kubo, Hirotsugu; Shimizu, Tatsuya

2018-01-18

Confluent cultured cells on a temperature-responsive culture dish can be harvested as an intact cell sheet by decreasing temperature below 32°C. A three-dimensional (3-D) tissue can be fabricated by the layering of cell sheets. A resulting 3-D multilayered cell sheet-tissue on a temperature-responsive culture dish can be also harvested without any damage by only temperature decreasing. For shortening the fabrication time of the 3-D multilayered constructs, we attempted to layer cell sheets on a temperature-responsive culture dish with centrifugation. However, when a cell sheet was attached to the culture surface with a conventional centrifuge at 22-23°C, the cell sheet hardly adhere to the surface due to its noncell adhesiveness. Therefore, in this study, we have developed a heating centrifuge. In centrifugation (55g) at 36-37°C, the cell sheet adhered tightly within 5 min to the dish without significant cell damage. Additionally, centrifugation accelerated the cell sheet-layering process. The heating centrifugation shortened the fabrication time by one-fifth compared to a multilayer tissue fabrication without centrifugation. Furthermore, the multilayered constructs were finally detached from the dishes by decreasing temperature. This rapid tissue-fabrication method will be used as a valuable tool in the field of tissue engineering and regenerative therapy. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018. © 2018 American Institute of Chemical Engineers.

Design of Faraday cup ion detectors built by thin film deposition

Energy Technology Data Exchange (ETDEWEB)

Szalkowski, G.A., E-mail: gszalkowski3@gatech.edu [Department of Nuclear Engineering, Georgia Institute of Technology, 770 State St., Atlanta, GA 30332 (United States); Darrow, D.S., E-mail: ddarrow@pppl.gov [Princeton Plasma Physics Laboratory, P. O. Box 451, Princeton, NJ 08543 (United States); Cecil, F.E., E-mail: fcecil@mines.edu [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States)

2017-03-11

Thin film Faraday cup detectors can provide measurements of fast ion loss from magnetically confined fusion plasmas. These multilayer detectors can resolve the energy distribution of the lost ions in addition to giving the total loss rate. Prior detectors were assembled from discrete foils and insulating sheets. Outlined here is a design methodology for creating detectors using thin film deposition that are suited to particular scientific goals. The intention is to use detectors created by this method on the Joint European Torus (JET) and the National Spherical Torus Experiment-Upgrade (NSTX-U). The detectors will consist of alternating layers of aluminum and silicon dioxide, with layer thicknesses chosen to isolate energies of interest. Thin film deposition offers the advantage of relatively simple and more mechanically robust construction compared to other methods, as well as allowing precise control of film thickness. Furthermore, this depositional fabrication technique places the layers in intimate thermal contact, providing for three-dimensional conduction and dissipation of the ion-produced heating in the layers, rather than the essentially two-dimensional heat conduction in the discrete foil stack implementation.

Bioactive glass and hydroxyapatite thin films obtained by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Gyorgy, E. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG 36, 77125 Bucharest (Romania) and Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Barcelona, Campus UAB, 08193 Bellaterra (Spain)]. E-mail: egyorgy@icmab.es; Grigorescu, S. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG 36, 77125 Bucharest (Romania); Socol, G. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG 36, 77125 Bucharest (Romania); Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG 36, 77125 Bucharest (Romania); Janackovic, D. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Dindune, A. [Institute of Inorganic Chemistry of the Riga Technical University (Latvia); Plasma and Ceramic Technologies Ltd. (PCT Ltd.) (Latvia); Kanepe, Z. [Institute of Inorganic Chemistry of the Riga Technical University (Latvia); Plasma and Ceramic Technologies Ltd. (PCT Ltd.) (Latvia); Palcevskis, E. [Plasma and Ceramic Technologies Ltd. (PCT Ltd.) (Latvia); Zdrentu, E.L. [Institute of Biochemistry, Splaiul Independentei 296, Bucharest (Romania); Petrescu, S.M. [Institute of Biochemistry, Splaiul Independentei 296, Bucharest (Romania)

2007-07-31

Bioactive glass (BG), calcium hydroxyapatite (HA), and ZrO{sub 2} doped HA thin films were grown by pulsed laser deposition on Ti substrates. An UV KrF{sup *} ({lambda} = 248 nm, {tau} {>=} 7 ns) excimer laser was used for the multi-pulse irradiation of the targets. The substrates were kept at room temperature or heated during the film deposition at values within the (400-550 deg. C) range. The depositions were performed in oxygen and water vapor atmospheres, at pressure values in the range (5-40 Pa). The HA coatings were heat post-treated for 6 h in a flux of hot water vapors at the same temperature as applied during deposition. The surface morphology, chemical composition, and crystalline quality of the obtained thin films were studied by scanning electron microscopy, atomic force microscopy, and X-ray diffractometry. The films were seeded for in vitro tests with Hek293 (human embryonic kidney) cells that revealed a good adherence on the deposited layers. Biocompatibility tests showed that cell growth was better on HA than on BG thin films.

Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century

Science.gov (United States)

Coffel, Ethan D.; Horton, Radley M.; de Sherbinin, Alex

2018-01-01

As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100-250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world’s population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150-750 million person-days of exposure to wet bulb temperatures above those seen in today’s most severe heat waves by 2070-2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.

Photoluminescence properties of BaMoO4 amorphous thin films

International Nuclear Information System (INIS)

Marques, Ana Paula Azevedo; Melo, Dulce M.A. de; Longo, Elson; Paskocimas, Carlos A.; Pizani, Paulo S.; Leite, Edson R.

2005-01-01

BaMoO 4 amorphous and crystalline thin films were prepared from polymeric precursors. The BaMoO 4 was deposited onto Si wafers by means of the spinning technique. The structure and optical properties of the resulting films were characterized by FTIR reflectance spectra, X-ray diffraction (XRD), atomic force microscopy (AFM) and optical reflectance. The bond Mo-O present in BaMoO 4 was confirmed by FTIR reflectance spectra. XRD characterization showed that thin films heat-treated at 600 and 200 deg. C presented the scheelite-type crystalline phase and amorphous, respectively. AFM analyses showed a considerable variation in surface morphology by comparing samples heat-treated at 200 and 600 deg. C. The reflectivity spectra showed two bands, positioned at 3.38 and 4.37 eV that were attributed to the excitonic state of Ba 2+ and electronic transitions within MoO 2- 4 , respectively. The optical band gaps of BaMoO 4 were 3.38 and 2.19 eV, for crystalline (600 deg. C/2 h) and amorphous (200 deg. C/8 h) films, respectively. The room-temperature luminescence spectra revealed an intense single-emission band in the visible region. The PL intensity of these materials was increased upon heat-treatment. The excellent optical properties observed for BaMoO 4 amorphous thin films suggested that this material is a highly promising candidate for photoluminescent applications

Tin oxide transparent thin-film transistors

International Nuclear Information System (INIS)

Presley, R E; Munsee, C L; Park, C-H; Hong, D; Wager, J F; Keszler, D A

2004-01-01

A SnO 2 transparent thin-film transistor (TTFT) is demonstrated. The SnO 2 channel layer is deposited by RF magnetron sputtering and then rapid thermal annealed in O 2 at 600 deg. C. The TTFT is highly transparent, and enhancement-mode behaviour is achieved by employing a very thin channel layer (10-20 nm). Maximum field-effect mobilities of 0.8 cm 2 V -1 s -1 and 2.0 cm 2 V -1 s -1 are obtained for enhancement- and depletion-mode devices, respectively. The transparent nature and the large drain current on-to-off ratio of 10 5 associated with the enhancement-mode behaviour of these devices may prove useful for novel gas-sensor applications

The transgenerational effects of heat stress in the nematode Caenorhabditis remanei are negative and rapidly eliminated under direct selection for increased stress resistance in larvae.

Science.gov (United States)

Sikkink, Kristin L; Ituarte, Catherine M; Reynolds, Rose M; Cresko, William A; Phillips, Patrick C

2014-12-01

Parents encountering stress environments can influence the phenotype of their offspring in a form of transgenerational phenotypic plasticity that has the potential to be adaptive if offspring are thereby better able to deal with future stressors. Here, we test for the existence of anticipatory parental effects in the heat stress response in the highly polymorphic nematode Caenorhabditis remanei. Rather providing an anticipatory response, parents subject to a prior heat stress actually produce offspring that are less able to survive a severe heat shock. Selection on heat shock resistance within the larvae via experimental evolution leads to a loss of sensitivity (robustness) to environmental variation during both the parental and larval periods. Whole genome transcriptional analysis of both ancestor and selected lines shows that there is weak correspondence between genetic pathways induced via temperature shifts during parental and larval periods. Parental effects can evolve very rapidly via selection acting directly on offspring. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle molding

International Nuclear Information System (INIS)

Wang, Guilong; Zhao, Guoqun; Wang, Xiaoxin

2013-01-01

Highlights: ► Higher cavity surface temperature reduces tensile strength of non-weldline part. ► Higher cavity surface temperature increases weldline tensile strength for PS and PP. ► Higher cavity surface temperature reduces weldline tensile strength for ABS, ABS/PMMA, ABS/PMMA/nano-C a CO 3 and FRPP. ► Tensile strength is reduced more by the weldline than impact strength. ► FRPP has the lowest weld line factor than other plastics without reinforced fibers. - Abstract: Rapid heat cycle molding (RHCM) is a recently developed injection molding technology to enhance surface esthetic of the parts. By rapid heating and cooling of mold cavity surfaces in molding process, it can greatly alleviate or even eliminate the surface defects such as flow mark, weld line, glass fiber rich surface, silver mark, jetting mark, and swirl mark, and also improve gloss finish and dimensional accuracy without prolonging the molding cycle. Besides surface esthetic, mechanical property is also a very import issue for the molded plastic part. The aim of this study is focusing on the effects of the cavity surface temperature just before filling, T cs , in RHCM on the mechanical strength of the specimen with and without weld line. Six kinds of typical plastics including polystyrene (PS), polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene/polymethylmethacrylate (ABS/PMMA), ABS/PMMA/nano-C a CO 3 and glass fiber reinforced polypropylene (FRPP) are used in experiments. The specimens with and without a weld line are produced with the different T cs on the developed electric-heating RHCM system. Tensile tests and notched Izod impact tests are conducted to characterize the mechanical strength of the specimens molded with different cavity surface temperatures. Simulations, differential scanning calorimetry (DSC), scanning electron microscope (SEM) and optical microscope are implemented to explain the impact mechanism of T cs on mechanical properties

Numerical and experimental analysis of a thin liquid film on a rotating disk related to development of a spacecraft absorption cooling system

Science.gov (United States)

Faghri, Amir; Swanson, Theodore D.

1989-01-01

The numerical and experimental analysis of a thin liquid film on a rotating and a stationary disk related to the development of an absorber unit for a high capacity spacecraft absorption cooling system, is described. The creation of artificial gravity by the use of a centrifugal field was focused upon in this report. Areas covered include: (1) One-dimensional computation of thin liquid film flows; (2) Experimental measurement of film height and visualization of flow; (3) Two-dimensional computation of the free surface flow of a thin liquid film using a pressure optimization method; (4) Computation of heat transfer in two-dimensional thin film flow; (5) Development of a new computational methodology for the free surface flows using a permeable wall; (6) Analysis of fluid flow and heat transfer in a thin film in the presence and absence of gravity; and (7) Comparison of theoretical prediction and experimental data. The basic phenomena related to fluid flow and heat transfer on rotating systems reported here can also be applied to other areas of space systems.

Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition

Directory of Open Access Journals (Sweden)

Jingjin Wu

2016-08-01

Full Text Available The 4 at. % zirconium-doped zinc oxide (ZnO:Zr films grown by atomic layer deposition (ALD were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV–vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350–550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

Rapid mixing chemical oxidative polymerization: an easy route to ...

Indian Academy of Sciences (India)

Administrator

(SDCNTs)/PANI nanofibres (NFs) has been prepared using an easy in situ rapid mixing chemical ... SDCNTs thin film was obtained using thermal chemical vapour deposition method in ... In the next step, 250 mL of aqueous HCl was taken in a.

Production of thin carbon stripper foils using heated-substrates in a cathodic arc deposition system

International Nuclear Information System (INIS)

Merchant, A.R.; Lobanov, N.; Elliman, R.G.; Ophel, T.R.; Rode, A.; Weisser, D.C.; Turkentine, R.B.

1998-01-01

The lifetime of carbon stripper foil can have a marked impact on the successful running of a beam line. Standard techniques for production of carbon stripper foils include evaporation of carbon (ec) and laser-pulsed ablation (Ipa). Recent work by a using Ipa has been successful in substantially increasing the lifetime of a very thin foil. The suspected mechanism for the increased lifetime of the foil is that the amorphous carbon foil is density-matched to that of graphite (around 2.26g/cc). In this work, we attempt to reproduce this result by producing carbon stripper foils with a mass-density similar to graphite using a cathodic arc deposition system. The cathodic arc is well known for the production of tetrahedral amorphous carbon: a high density, high stress form of carbon with over 90% sp 3 -like bonds; to reduce the density of the carbon and promote more graphitic structure, a high bias was initially attempted but this proved unsuccessful. Another method is to use a heated-substrate holder to reduce compressive stress within the deposited film. The performance of the density-matched carbon stripper foils and the implications for future production of high-quality carbon stripper foils in our laboratory will be discussed. (authors)

Frequency-domain Harman technique for rapid characterization of bulk and thin film thermoelectric materials

Science.gov (United States)

Moran, Samuel

Nanostructured thermoelectrics, often in the form of thin films, may potentially improve the generally poor efficiency of bulk thermoelectric power generators and coolers. In order to characterize the efficiency of these new materials it is necessary to measure their thermoelectric figure of merit, ZT. The only direct measurement of ZT is based on the Harman technique and relies on measuring the voltage drop across a sample subjected to a passing continuous current. Application of this technique to thin films is currently carried out as a time-domain measurement of the voltage as the thermal component decays after switching off an applied voltage. This work develops a technique for direct simultaneous measurement of figure of merit and Seebeck coefficient from the harmonic response of a thermoelectric material under alternating current excitation. A thermocouple mounted on the top surface measures voltage across the device as the frequency of the applied voltage is varied. A thermal model allows the sample thermal conductivity to also be determined and shows good agreement with measurements. This technique provides improved signal-to-noise ratio and accuracy compared to time-domain ZT measurements for comparable conditions while simultaneously measuring Seebeck coefficient. The technique is applied to both bulk and thin film thermoelectric samples.

An ultra-thin miniature loop heat pipe cooler for mobile electronics

International Nuclear Information System (INIS)

Zhou, Guohui; Li, Ji; Lv, Lucang

2016-01-01

Highlights: • A 1.2 mm thick miniature loop heat pipe was developed. • The mLHP can manage a wide range of heat loads at natural convection. • A minimum mLHP thermal resistance of 0.111 °C/W was achieved at 11 W. • The proposed mLHP is a promising solution for cooling mobile electronics. - Abstract: In this paper, we present a miniature loop heat pipe (mLHP) employing a 1.2 mm thick flat evaporator and a vapor line, liquid line and condenser with a 1.0 mm thickness. The mLHP employs an internal wick structure fabricated of sintered fine copper mesh, comprised of a primary wick structure in the evaporator to provide the driving force for circulating the working fluid, and a secondary wick inside the liquid line to promote the flow of condensed working fluid back to the evaporator. All tests were conducted under air natural convection at an ambient temperature of 24 ± 1 °C. The proposed mLHP demonstrated stable start-up behavior at a low heat load of 2 W in the horizontal orientation with an evaporator temperature of 43.9 °C and efficiently dissipates a maximum heat load of 12 W without dry-out occurring. A minimum mLHP thermal resistance of 0.111 °C/W was achieved at a heat load of 11 W in a gravity favorable operation mode, at which the evaporator temperature was about 97.2 °C. In addition, an analytical analysis was conducted, and the devised equation could be used to evaluate the performance of the mLHP.

Rapid control of mold temperature during injection molding process

Energy Technology Data Exchange (ETDEWEB)

Liparoti, Sara; Titomanlio, Giuseppe [Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II, 132, 84084 Fisciano (Italy); Hunag, Tsang Min; Cakmak, Mukerrem [Department of Polymer Engineering, The University of Akron, Akron, OH 44325 (United States); Sorrentino, Andrea [Institute for Polymers, Composite and Biomaterials (IPCB) - CNR, P. Enrico Fermi 1, 80055 Portici (Italy)

2015-05-22

The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

Shell-side single-phase flows and heat transfer in shell-and-tube heat exchangers, 4

International Nuclear Information System (INIS)

Matsushita, Hitoshi; Nakayama, Wataru; Yanagida, Takehiko; Kudo, Akio.

1987-01-01

Refering to the results of our previous works, a procedure for estimating the distribution of heat flux in shell-and-tube heat exchangers is proposed. The steam generator used in a high temperature reactor plant is taken up as the subject of analysis. Particular attention is paid to critical conditions for burnout and the strength of material in high temperature conditions. It is found that the distribution of heat transfer coefficient on the shell-side is crucial to the occurrence of burnout in the tubes. The use of a relatively large inlet nozzle (the ratio of its diameter to the shell is roughly half) is recommended. A low level of thermal stress on heat transfer tubes can be realized by the adoption of a relatively thin 2.25 Cr-1 Mo Steel tube wall of 1.24 mm thickness. (author)

Synthesis of photosensitive nanograined TiO2 thin films by SILAR method

International Nuclear Information System (INIS)

Patil, U.M.; Gurav, K.V.; Joo, Oh-Shim; Lokhande, C.D.

2009-01-01

Nanocrystalline TiO 2 thin films are deposited by simple successive ionic layer adsorption and reaction (SILAR) method on glass and fluorine-doped tin oxide (FTO)-coated glass substrate from aqueous solution. The as-deposited films are heat treated at 673 K for 2 h in air. The change in structural, morphological and optical properties are studied by means of X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and UV-vis-NIR spectrophotometer. The results show that the SILAR method allows the formation of anatase, nanocrystalline, and porous TiO 2 thin films. The heat-treated film showed conversion efficiency of 0.047% in photoelectrochemical cell with 1 M NaOH electrolyte.

Meanings of thinness and dysfunctional eating in black South ...

African Journals Online (AJOL)

meanings of thinness and food refusal may not only vary from culture to culture, but ... the rapidly westernizing socio-cultural context of post-apartheid South Africa. Method: Four .... she first arrived in South Africa as an immigrant from a French-.

Investigation of monitoring technologies for heat transfer corrosion in reprocessing equipment

International Nuclear Information System (INIS)

Tsukatani, I.; Kiuchi, K.

2004-01-01

Two types of in-situ monitoring techniques using electrical resistance methods were developed for estimating the wall thinning of heat transfer tubes used in evaporators for Purex process on commercial reprocessing plants. The corrosion rate is accelerated with oxidizer ions formed by the thermal decomposition of nitric acid under heat flux. An in-situ corrosion sensor was developed for estimating the corrosion rate of heat transfer tubes using miniature heat transfer tube specimens under heat flux control. It is possible to simulate the heating condition as same as heat transfer tubes. The applicability was evaluated by setting it in gas-liquid separator in a mock-up evaporator for acid recovery. The sensitivity of electric resistance methods is increased with decreasing the residual thickness of probe tube. The other is the electrical potential drop method using direct current so-called the field signature method. It is applicable to estimate the corrosiveness of reprocessing nitric acid by setting it on the drain tube in evaporator. The sensitivity to the thinning rate of tubes wall machined artificially was obtained within ±10% to the wall thickness. It has the non-sensitive region nearly 0.1mm up to begin working. The practical applicability has been also evaluated by setting it in a mock-up evaporator. (author)

Heat pipe nuclear reactor for space power

Science.gov (United States)

Koening, D. R.

1976-01-01

A heat-pipe-cooled nuclear reactor has been designed to provide 3.2 MWth to an out-of-core thermionic conversion system. The reactor is a fast reactor designed to operate at a nominal heat-pipe temperature of 1675 K. Each reactor fuel element consists of a hexagonal molybdenum block which is bonded along its axis to one end of a molybdenum/lithium-vapor heat pipe. The block is perforated with an array of longitudinal holes which are loaded with UO2 pellets. The heat pipe transfers heat directly to a string of six thermionic converters which are bonded along the other end of the heat pipe. An assembly of 90 such fuel elements forms a hexagonal core. The core is surrounded by a thermal radiation shield, a thin thermal neutron absorber, and a BeO reflector containing boron-loaded control drums.

Heat stress related dairy cow mortality during heat waves and control periods in rural Southern Ontario from 2010?2012

OpenAIRE

Bishop-Williams, Katherine E.; Berke, Olaf; Pearl, David L.; Hand, Karen; Kelton, David F.

2015-01-01

Background Heat stress is a physiological response to extreme environmental heat such as heat waves. Heat stress can result in mortality in dairy cows when extreme heat is both rapidly changing and has a long duration. As a result of climate change, heat waves, which are defined as 3 days of temperatures of 32 ?C or above, are an increasingly frequent extreme weather phenomenon in Southern Ontario. Heat waves are increasing the risk for on-farm dairy cow mortality in Southern Ontario. Heat st...

Numerical Modelling of Indution Heating - Fundamentals

DEFF Research Database (Denmark)

Zhang, Wenqi

Induction heating is extensively used for brazing and heat treatment of materials to produce consumer and industrial products; structural assemblies; electrical and electronic products; mining, machine, and hand tools; ordnance equipment; and aerospace assemblies. It is often applied when rapid a...

Rapid and Complete Enzyme Hydrolysis of Lignocellulosic Nanofibrils

Science.gov (United States)

Raquel Martin-Sampedro; Ilari Filpponen; Ingrid C. Hoeger; J.Y. Zhu; Janne Laine; Orlando J. Rojas

2012-01-01

Rapid enzymatic saccharification of lignocellulosic nanofibrils (LCNF) was investigated by monitoring nanoscale changes in mass via quartz crystal microgravimetry and also by measuring reducing sugar yields. In only a few minutes LCNF thin films were completely hydrolyzed upon incubation in multicomponent enzyme systems. Conversion to sugars and oligosaccharides of...

New device architecture of a thermoelectric energy conversion for recovering low-quality heat

Science.gov (United States)

Kim, Hoon; Park, Sung-Geun; Jung, Buyoung; Hwang, Junphil; Kim, Woochul

2014-03-01

Low-quality heat is generally discarded for economic reasons; a low-cost energy conversion device considering price per watt, /W, is required to recover this waste heat. Thin-film based thermoelectric devices could be a superior alternative for this purpose, based on their low material consumption; however, power generated in conventional thermoelectric device architecture is negligible due to the small temperature drop across the thin film. To overcome this challenge, we propose new device architecture, and demonstrate approximately 60 Kelvin temperature differences using a thick polymer nanocomposite. The temperature differences were achieved by separating the thermal path from the electrical path; whereas in conventional device architecture, both electrical charges and thermal energy share same path. We also applied this device to harvest body heat and confirmed its usability as an energy conversion device for recovering low-quality heat.

Crystallization of Sr0.5Ba0.5Nb2O6 Thin Films on LaNiO3 Electrodes by RF Magnetron Reactive Sputtering

Science.gov (United States)

Jong, Chao-An; Gan, Jon-Yiew

2000-02-01

Strontium barium niobium (Sr0.5Ba0.5Nb2O6) (SBN) thin films are prepared on conductive-oxide LNO (LaNiO3) electrodes by the rf magnetron sputtering system. Instead of conventional furnace annealing, SBN thin films are crystallized by rapid thermal annealing (RTA) above 700°C for 5 min. The textured SBN films are crystallized with two orientations: one is the (001) or (310) direction, and the other is the (002) or (620) direction. Films compositions measured by the electron spectroscopy of chemical analysis (ESCA) quantitative analysis method show nearly the same stoichiometric ratio as the target. The depth profiles of SBN films and the target are examined by secondary ion mass spectrometer (SIMS). The concentrations of the films are quite uniform. After being heat treated at 800°C for 5 min by RTA, La and Ni diffuse into the SBN film. The diffusion coefficient of La in SBN films is also calculated.

A Green's function solution for a rectangular heat source on an infinite plate

International Nuclear Information System (INIS)

Bainbridge, B.L.

1989-01-01

The applications associated with a rectangular heat source on an infinite plate range from integrated circuits to thin film heat flux sensors on thin substrates. The particular problem from which the solution is developed concerns the use of a resistive strip for monitoring currents generated in circuits exposed to electromagnetic fields. The Green's function formulation is solved by using early and late time approximations for which analytical solutions can be derived. In this paper expressions are developed for three sets of boundary conditions and compared to the experimental performance of a physical device

Heat-Related Illnesses

Medline Plus

Full Text Available ... moist, pale skin, rapid pulse, elevated or lowered blood pressure, nausea, loss of consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool the person further by positioning ...

Multiscale solutions of radiative heat transfer by the discrete unified gas kinetic scheme

Science.gov (United States)

Luo, Xiao-Ping; Wang, Cun-Hai; Zhang, Yong; Yi, Hong-Liang; Tan, He-Ping

2018-06-01

The radiative transfer equation (RTE) has two asymptotic regimes characterized by the optical thickness, namely, optically thin and optically thick regimes. In the optically thin regime, a ballistic or kinetic transport is dominant. In the optically thick regime, energy transport is totally dominated by multiple collisions between photons; that is, the photons propagate by means of diffusion. To obtain convergent solutions to the RTE, conventional numerical schemes have a strong dependence on the number of spatial grids, which leads to a serious computational inefficiency in the regime where the diffusion is predominant. In this work, a discrete unified gas kinetic scheme (DUGKS) is developed to predict radiative heat transfer in participating media. Numerical performances of the DUGKS are compared in detail with conventional methods through three cases including one-dimensional transient radiative heat transfer, two-dimensional steady radiative heat transfer, and three-dimensional multiscale radiative heat transfer. Due to the asymptotic preserving property, the present method with relatively coarse grids gives accurate and reliable numerical solutions for large, small, and in-between values of optical thickness, and, especially in the optically thick regime, the DUGKS demonstrates a pronounced computational efficiency advantage over the conventional numerical models. In addition, the DUGKS has a promising potential in the study of multiscale radiative heat transfer inside the participating medium with a transition from optically thin to optically thick regimes.

Crystallization of sol-gel derived lead zirconate titanate thin films in argon and oxygen atmospheres

Energy Technology Data Exchange (ETDEWEB)

Bursill, L A [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Brooks, K G [Ecole Polytechnique Federale, Lausanne (Switzerland)

1994-12-31

Electron diffraction and high-resolution electron microscopic techniques are applied to reveal the mechanisms of crystallization of 75 nm thin films of ferroelectric lead-zirconate-titanate (PZT). Sol-gel methods, followed by pyrolysis at 350 deg C, were used to provide a common starting point after which a variety of rapid-thermal annealing (RTA) experiments in the temperature range 400-700 deg C were made in argon, oxygen and nitrogen/hydrogen atmospheres. The results are interpreted in terms of the crystal chemical analysis, which points out that partial pressure of oxygen and heating rate are important experimental parameters which must be controlled if ferroelectric perovskite-type Pb{sub 2}ZrTiO{sub 6}, rather than pyrochlore-type Pb{sub 2}ZrTiO{sub 6+x}, where O < X < 1 or -1 < X < O, is to be obtained after the RTA step. Thus significant improvements in the crystallization of perovskite-type PZT were clearly demonstrated by using argon atmospheres for the RTA step. The results have significance for the production of high-quality ferroelectric thin films, with improved switching and fatigue characteristics, since even small amounts of the pyrochlore phase prove detrimental for these properties. 18 refs., 1 tab., 10 figs.

Heat flux microsensor measurements and calibrations

Science.gov (United States)

Terrell, James P.; Hager, Jon M.; Onishi, Shinzo; Diller, Thomas E.

1992-01-01

A new thin-film heat flux gage has been fabricated specifically for severe high temperature operation using platinum and platinum-10 percent rhodium for the thermocouple elements. Radiation calibrations of this gage were performed at the AEDC facility over the available heat flux range (approx. 1.0 - 1,000 W/cu cm). The gage output was linear with heat flux with a slight increase in sensitivity with increasing surface temperature. Survivability of gages was demonstrated in quench tests from 500 C into liquid nitrogen. Successful operation of gages to surface temperatures of 750 C has been achieved. No additional cooling of the gages is required because the gages are always at the same temperature as the substrate material. A video of oxyacetylene flame tests with real-time heat flux and temperature output is available.

MultiLayer solid electrolyte for lithium thin film batteries

Science.gov (United States)

Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

2015-07-28

A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

Magnetite thin films: A simulational approach

International Nuclear Information System (INIS)

Mazo-Zuluaga, J.; Restrepo, J.

2006-01-01

In the present work the study of the magnetic properties of magnetite thin films is addressed by means of the Monte Carlo method and the Ising model. We simulate LxLxd magnetite thin films (d being the film thickness and L the transversal linear dimension) with periodic boundary conditions along transversal directions and free boundary conditions along d direction. In our model, both the three-dimensional inverse spinel structure and the interactions scheme involving tetrahedral and octahedral sites have been considered in a realistic way. Results reveal a power-law dependence of the critical temperature with the film thickness accordingly by an exponent ν=0.81 and ruled out by finite-size scaling theory. Estimates for the critical exponents of the magnetization and the specific heat are finally presented and discussed

Heat-induced accumulation and futile cycling of trehalose in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Hottiger, T.; Schmutz, P.; Wiemken, A.

1987-01-01

Heat shock resulted in rapid accumulation of large amounts of trehalose in Saccharomyces cerevisiae. In cultures growing exponentially on glucose, the trehalose content of the cells increased from 0.01 to 1 g/g of protein within 1 h after the incubation temperature was shifted from 27 to 40 0 C. When the temperature was readjusted to 27 0 C, the accumulated trehalose was rapidly degraded. In parallel, the activity of the trehalose-phosphate synthase, the key enzyme of trehalose biosynthesis, increased about six fold during the heat shock and declined to normal level after readjustment of the temperature. Surprisingly, the activity of neutral trehalase, the key enzyme of trehalose degradation, also increased about threefold during the heat shock and remained almost constant during recovery of the cells at 27 0 C. In pulse-labeling experiments with [ 14 C] glucose, trehalose was found to be turned over rapidly in heat-shocked cells, indicating that both anabolic and catabolic enzymes of trehalose metabolism were active in vivo. Possible functions of the heat-induced accumulation of trehalose and its rapid turnover in an apparently futile cycle during heat shock are discussed

Thin Glass Coatings for the Corrosion Protection of Metals

DEFF Research Database (Denmark)

Lampert, Felix

in corrosion sensitive applications. Since the deposition of SiOx thin films is a well-established technology, the SOG technology was directly benchmarked to PVD-based SiO2 coatings. The coating adhesion was assessed by cross cut testing and increasing load scratch testing and the efficiency of the sub...... with localized corrosion and do not impact the heat transfer or the component performance. The herein presented approach focuses primarily on the formation of SiOx-like thin films from Hydrogen Silsesquioxane (HSQ) –based “spin-on-glass” (SOG) precursor. The technology is well known for the deposition...

Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

Directory of Open Access Journals (Sweden)

Swati Arora

2017-01-01

Full Text Available Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te and bismuth (Bi were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD and scanning electron microscopy (SEM to show granular growth.

Performance Measurements of a 7 mm-Diameter Hydrogen Heat Pipe

International Nuclear Information System (INIS)

Abdel-Bary, M.; Abdel-Samad, S.; Kiliana, K.; Ritman, J.; Abdel-Bary, M.; Abdel-Samad, S.

2008-01-01

A gravity assisted heat pipe with 7-mm diameter has been developed and tested to cool a liquid hydrogen target for extracted beam experiments at COSY. The liquid flowing down from the condenser surface is separated from the vapor flowing up by a thin wall 3 mm diameter plastic tube located concentrically inside the heat pipe. The heat pipe was tested at different inclination angles with respect to the horizontal plane. The heat pipe showed good operating characteristics because of the low radiation heat load from the surroundings, low heat capacity due to the small mass, higher sensitivity to heat loads (to overcome the heat load before the complete vaporization of the liquid in the target cell) due to the higher vapor speed inside the heat pipe which transfers the heat load to the condenser

Heat-Related Illnesses

Medline Plus

Full Text Available ... weak pulse; rapid, shallow breathing; vomiting; and increased body temperature of more than 104 degrees. People with ... nausea, loss of consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool ...

Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass

Directory of Open Access Journals (Sweden)

Mason L. Terry

2007-01-01

Full Text Available The changes in open-circuit voltage (Voc, short-circuit current density (Jsc, and internal quantum efficiency (IQE of aLuminum induced crystallization, ion-assisted deposition (ALICIA polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.

Rapid plasma heating by collective interactions, using strong turbulence and relativistic electron beams

International Nuclear Information System (INIS)

Wharton, C.B.

1977-01-01

A multi-kilovolt, moderate density plasma was generated in a magnetic mirror confinement system by two methods: turbulent heating and relativistic electron beam. Extensive diagnostic development permitted the measurement of important plasma characteristics, leading to interesting and novel conclusions regarding heating and loss mechanisms. Electron and ion heating mechanisms were categorized, and parameter studies made to establish ranges of importance. Nonthermal ion and electron energy distributions were measured. Beam propagation and energy deposition studies yielded the spatial dependence of plasma heating

A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer

Science.gov (United States)

Sui, Jize; Zhao, Peng; Cheng, Zhengdong; Zheng, Liancun; Zhang, Xinxin

2017-02-01

The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized "n-diffusion theory," which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponent n and the modified material parameter K 0 introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial to n with high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system.

Advanced platform for the in-plane ZT measurement of thin films

Science.gov (United States)

Linseis, V.; Völklein, F.; Reith, H.; Nielsch, K.; Woias, P.

2018-01-01

The characterization of nanostructured samples with at least one restricted dimension like thin films or nanowires is challenging, but important to understand their structure and transport mechanism, and to improve current industrial products and production processes. We report on the 2nd generation of a measurement chip, which allows for a simplified sample preparation process, and the measurement of samples deposited from the liquid phase using techniques like spin coating and drop casting. The new design enables us to apply much higher temperature gradients for the Seebeck coefficient measurement in a shorter time, without influencing the sample holder's temperature distribution. Furthermore, a two membrane correction method for the 3ω thermal conductivity measurement will be presented, which takes the heat loss due to radiation into account and increases the accuracy of the measurement results significantly. Errors caused by different sample compositions, varying sample geometries, and different heat profiles are avoided with the presented measurement method. As a showcase study displaying the validity and accuracy of our platform, we present temperature-dependent measurements of the thermoelectric properties of an 84 nm Bi87Sb13 thin film and a 15 μm PEDOT:PSS thin film.

Soft chemistry routes to transparent metal oxide thin films. The case of sol–gel synthesis and structural characterization of Ta{sub 2}O{sub 5} thin films from tantalum chloromethoxide

Energy Technology Data Exchange (ETDEWEB)

Epifani, Mauro, E-mail: mauro.epifani@le.imm.cnr.it [Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via Monteroni, 73100 Lecce (Italy); Zamani, Reza [Catalonia Institute for Energy Research, IREC c/Jardins de les Dones de Negre, 1, 08930-Sant Adria del Besos, Barcelona (Spain); Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, 08193 Bellaterra, CAT (Spain); Arbiol, Jordi [Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, 08193 Bellaterra, CAT (Spain); Institucio Catalana de Recerca i Estudis Avançats, ICREA, 08010, Barcelona (Spain); Fabrega, Cristian; Andreu, Teresa [Catalonia Institute for Energy Research, IREC c/Jardins de les Dones de Negre, 1, 08930-Sant Adria del Besos, Barcelona (Spain); Pace, Giovanni Battista; Siciliano, Pietro [Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via Monteroni, 73100 Lecce (Italy); Morante, Joan R. [Catalonia Institute for Energy Research, IREC c/Jardins de les Dones de Negre, 1, 08930-Sant Adria del Besos, Barcelona (Spain); M2E-IN2UB-XaRMAE, Departament d’Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona, CAT (Spain)

2014-03-31

Ta{sub 2}O{sub 5} thin films were prepared by spin-coating methanol solutions of Ta chloromethoxide. It was prepared by reacting TaCl{sub 5} with methanol, followed by water addition (H{sub 2}O: Ta molar ratio was 16). Thin films were deposited by spin-coating onto SiO{sub 2}/Si substrates, followed by drying at 90 °C and heat-treatment up to 700 °C. The films were characterized by X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. Crystallization was obtained only after heating at 700 °C, in the Ta{sub 2}O{sub 5} orthorhombic phase. The resulting films had a thickness of 100 nm. Their structure was constituted by porous crystals with size up to 50 nm, while the pores had a size of about 10 nm. The results demonstrated that TaCl{sub 5} is very convenient precursor for the wet chemical synthesis of Ta{sub 2}O{sub 5} thin films. - Highlights: • Development of convenient solution synthesis of Ta{sub 2}O{sub 5} thin films; • The precursor chemistry was established and related to the synthesis process; • Uniform films crystallized in the most stable orthorombic Ta{sub 2}O{sub 5} phase;.

Radioisotope thermoelectric generator/thin fragment impact test

International Nuclear Information System (INIS)

Reimus, M.A.H.; Hinckley, J.E.

1998-01-01

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238 Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the convertor housing, failure of one fueled clad, and release of a small quantity of fuel

Program Computes Flows Of Fluids And Heat

Science.gov (United States)

Cullimore, Brent; Ring, Steven; Welch, Mark

1993-01-01

SINDA'85/FLUINT incorporates lumped-parameter-network and one-dimensional-flow mathematical models. System enables analysis of mutual influences of thermal and flow phenomena. Offers two finite-difference numerical solution techniques: forward-difference explicit approximation and Crank-Nicholson approximation. Enables simulation of nonuniform heating and facilitates mathematical modeling of thin-walled heat exchangers. Ability to model nonequilibrium behavior within two-phase volumes included. Recent changes in program improve modeling of real evaporator pumps and other capillary-assist evaporators. Written in FORTRAN 77.

Bubble development and fission gas release during rapid heating of 18 GWd/TeU UO2

International Nuclear Information System (INIS)

Small, G.J.

1985-01-01

Small samples (approximately 50 mg) of UO 2 irradiated to 18 GWd/TeU have been heated rapidly in an out-of-pile furnace. Ramp rates were in the range 10-80 deg. C.s -1 , peak temperatures varied from 1400 deg. C to 2500 deg. C and dwell times from one to fifteen min. The specimens were sealed in small capsules which were subsequently pierced to determine the total amount of fission gas ( 85 Kr) released during each test. Changes in the size and number of gas bubbles on grain boundaries were examined using SEM, TEM, replication and fractography techniques will be employed later. In this paper are reported the first series of gas release results and some metallography. The results are compared with related experiments and some qualitative conclusions are drawn regarding the mechanisms and kinetics of transient fission gas behaviour. (author)

Theoretical study of evaporation heat transfer in horizontal microfin tubes: stratified flow model

Energy Technology Data Exchange (ETDEWEB)

Honda, H; Wang, Y S [Kyushu Univ., Inst. for Materials Chemistry and Engineering, Kasuga, Fukuoka (Japan)

2004-08-01

The stratified flow model of evaporation heat transfer in helically grooved, horizontal microfin tubes has been developed. The profile of stratified liquid was determined by a theoretical model previously developed for condensation in horizontal microfin tubes. For the region above the stratified liquid, the meniscus profile in the groove between adjacent fins was determined by a force balance between the gravity and surface tension forces. The thin film evaporation model was applied to predict heat transfer in the thin film region of the meniscus. Heat transfer through the stratified liquid was estimated by using an empirical correlation proposed by Mori et al. The theoretical predictions of the circumferential average heat transfer coefficient were compared with available experimental data for four tubes and three refrigerants. A good agreement was obtained for the region of Fr{sub 0}<2.5 as long as partial dry out of tube surface did not occur. (Author)

Necessity for usage of geothermal heat pump

International Nuclear Information System (INIS)

Dimitrov, Konstantin; Armenski, Slave; Gacevski, Marijan

2004-01-01

Every day we are witnesses of constantly rapid increase of consumption of Electric energy in R. of Macedonia as so as in the other countries in all the world. This rapid increase of consumption of Electric energy independent of a lot of electrical units, which are applying in human life like: homes, administration and publication objects, as well as in industry. All of this conditions make us to thinking how is possible more rational consumption of electric energy in all areas in human life. One of the possible manners to reduce the consumption of electrical energy for heating and cooling is to use geothermal heat pumps. In this paper will be proposed geothermal heat pump, which is going to use the heat of earth by vertical and horizontal cupper pipe heat exchanger with data from-GHP (Geothermal Heat Pump) NORDIC, factory in Canada. Also, it will be examined all parameters and done comparison with already existing ones. It is analyzed comparison of GHP with other energy units and what it means for rational consumption of electric energy, economic saving and ecology saving. (Author)

Effect of Thermal Cycling on Zinc Antimonide Thin Film Thermoelectric Characteristics

DEFF Research Database (Denmark)

Mirhosseini, M.; Rezania, A.; Rosendahl, L.

2017-01-01

In this study, performance and stability of zinc antimonide thin film thermoelectric sample is analyzed under transient thermal conditions. The thermoelectric materials are deposited on glass based substrate where the heat flow is parallel with the thermoelectric element length. The specimen...

Heat-Related Illnesses

Medline Plus

Full Text Available ... weak pulse; rapid, shallow breathing; vomiting; and increased body temperature of more than 104 degrees. People with these ... nausea, loss of consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool the ...

A simple and rapid method for the determination of taxol produced by fungal endophytes from medicinal plants using high performance thin layer chromatography.

Science.gov (United States)

Gangadevi, V; Muthumary, J

2008-01-01

Taxol is an important anticancer drug used widely in the clinical field. In this study, some endophytic fungi were isolated from selected medicinal plants, and were screened for their potential in the production of taxol, using a rapid separation technique of high performance thin layer chromatography (HPTLC). Of the 20 screened fungi, only 13 fungal species produced taxol in the artificial culture medium. The results of HPTLC showed that the 13 fungal species had identical ultraviolet (UV) characteristics, positive reactivity with a spray reagent, yielding a blue spot, which turned to dark gray after 24 hours, and had Rf values identical to that of the authentic taxol. The amount of taxol was also quantified by comparing the peak area and the peak height of the fungal samples with those of authentic taxol.

Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Lei, Jih-Fen; Kiser, J. Douglas; Singh, Mrityunjay; Cuy, Mike; Blaha, Charles A.; Androjna, Drago

2000-01-01

An advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.

Marangoni instability in a thin film heated from below: Effect of nonmonotonic dependence of surface tension on temperature

Science.gov (United States)

Sarma, Rajkumar; Mondal, Pranab Kumar

2018-04-01

We investigate Marangoni instability in a thin liquid film resting on a substrate of low thermal conductivity and separated from the surrounding gas phase by a deformable free surface. Considering a nonmonotonic variation of surface tension with temperature, here we analytically derive the neutral stability curve for the monotonic and oscillatory modes of instability (for both the long-wave and short-wave perturbations) under the framework of linear stability analysis. For the long-wave instability, we derive a set of amplitude equations using the scaling k ˜(Bi) 1 /2 , where k is the wave number and Bi is the Biot number. Through this investigation, we demonstrate that for such a fluid layer upon heating from below, both monotonic and oscillatory instability can appear for a certain range of the dimensionless parameters, viz., Biot number (Bi ) , Galileo number (Ga ) , and inverse capillary number (Σ ) . Moreover, we unveil, through this study, the influential role of the above-mentioned parameters on the stability of the system and identify the critical values of these parameters above which instability initiates in the liquid layer.

Formation of Ag nanoparticles in percolative Ag–PbTiO3 composite thin films through lead-rich Ag–Pb alloy particles formed as transitional phase

International Nuclear Information System (INIS)

Hu, Tao; Wang, Zongrong; Su, Yanbo; Tang, Liwen; Shen, Ge; Song, Chenlu; Han, Gaorong; Weng, Wenjian; Ma, Ning; Du, Piyi

2012-01-01

The Ag nanoparticle dispersed percolative PbTiO 3 ceramic thin film was prepared in situ by sol–gel method with excess lead introduced into a sol precursor. The influence of excess lead and the heat treatment time on the formation of Ag nanoparticles was investigated by energy dispersive X-ray spectra, scanning electron microscopy, X-ray diffraction, and ultraviolet–visible absorption spectra. Results showed that the excess lead introduced into the sol precursor was in favor of the crystallization of the thin film and in favor of formation of the perovskite phase without the pyrochlore phase. Lead-rich Ag–Pb alloy particles first formed in the thin films and then decomposed to become large numbers of Ag nanoparticles of about 3 nm in size in the thin films when the heat treatment time was longer than 2 min. The content of the Ag nanoparticles increased with increasing the heat treatment time. The percolative behavior appears typically in the Ag nanoparticle dispersed thin films. The dielectric constant of the thin film was about 3 times of that without Ag nanoparticles. - Highlights: ► The Ag nanoparticles formed in the PbTiO 3 percolative ceramic thin film. ► The Ag–Pb alloy particles formed as transitional phase during thin film preparation. ► The lead-rich Ag–Pb alloy particles decomposed to form Ag nanoparticles in the film. ► Permittivity of the thin film is 3 times higher than that without Ag nanoparticles.

Structuring of thin-film polymer mixtures upon solvent evaporation

NARCIS (Netherlands)

Schaefer, C.; Michels, J.J.; van der Schoot, P.P.A.M.

2016-01-01

We theoretically study the impact of solvent evaporation on the dynamics of isothermal phase separation of ternary polymer solutions in thin films. In the early stages we obtain a spinodal length scale that decreases with time under the influence of ongoing evaporation. After that rapid demixing

Structuring of Thin-Film Polymer Mixtures upon Solvent Evaporation

NARCIS (Netherlands)

Schaefer, C.; Michels, J. J.; van der Schoot, P.

2016-01-01

We theoretically study the impact of solvent evaporation on the dynamics of isothermal phase separation of ternary polymer solutions in thin films. In the early stages we obtain a spinodal length scale that decreases with time under the influence of ongoing evaporation. After that rapid demixing

Molecular dynamics simulation of Cu/Au thin films under temperature gradient

International Nuclear Information System (INIS)

Li, Qibin; Peng, Xianghe; Peng, Tiefeng; Tang, Qizhong; Zhang, Xiaomin; Huang, Cheng

2015-01-01

Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

Molecular dynamics simulation of Cu/Au thin films under temperature gradient

Energy Technology Data Exchange (ETDEWEB)

Li, Qibin, E-mail: qibinli@cqu.edu.cn [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Peng, Xianghe [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Peng, Tiefeng, E-mail: pengtiefeng@cqu.edu.cn [State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Tang, Qizhong [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Xiaomin [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Huang, Cheng [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China)

2015-12-01

Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

Evaluation of empirical heat transfer models using TFG heat flux sensors

International Nuclear Information System (INIS)

De Cuyper, T.; Broekaert, S.; Chana, K.; De Paepe, M.; Verhelst, S.

2017-01-01

Thermodynamic engine cycle models are used to support the development of the internal combustion engine (ICE) in a cost and time effective manner. The sub model which describes the in-cylinder heat transfer from the working gases to the combustion chamber walls plays an important role in the accuracy of these simulation tools. The heat transfer affects the power output, engine efficiency and emissions of the engine. The most common heat transfer models in engine research are the models of Annand and Woschni. These models provide an instantaneous spatial averaged heat flux. In this research, prototype thin film gauge (TFG) heat flux sensors are used to capture the transient in-cylinder heat flux behavior within a production spark ignition (SI) engine as they are small, robust and able to capture the highly transient temperature swings. An inlet valve and two different zones of the cylinder head are instrumented with multiple TFG sensors. The heat flux traces are used to calculate the convection coefficient which includes all information of the convective heat transfer phenomena inside the combustion chamber. The implementation of TFG sensors inside the combustion chamber and the signal processing technique are discussed. The heat transfer measurements are used to analyze the spatial variation in heat flux under motored and fired operation. Spatial variation in peak heat flux was observed even under motored operation. Under fired operation the observed spatial variation is mainly driven by the flame propagation. Next, the paper evaluates the models of Annand and Woschni. These models fail to predict the total heat loss even with calibration of the models coefficients using a reference motored operating condition. The effect of engine speed and inlet pressure is analyzed under motored operation after calibration of the models. The models are able to predict the trend in peak heat flux value for a varying engine speed and inlet pressure. Next, the accuracy of the

New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

OpenAIRE

Budding, A.; Vaneker, T.H.J.

2013-01-01

In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of applications, but this study solely focuses on the application for powder -based three-dimensional printing (e.g. SLS, 3DP). This research is primarily interested in powder compaction for creating membrane...

Influence of time presetting procedure for rapid local heat;.ng on brazing temperature conditions

International Nuclear Information System (INIS)

Lezhnin, G.P.; Tul'skikh, V.E.

1985-01-01

Correlation of known and suggested presetting procedures for heating period during induction brazing was conducted. It is shown that brazing time must be established considering heat propagation during heating in order to obtain the assigned joint temperature regardless of heating rate change. Methods for temperature calculation in assigned zones of the joint are suggested. The suggested presetting procedure for heating time was applied for induction vacuum brazing of a tube of 12Kh18N10T steel to a pipe connection of VT20 alloy

Electrical contacts on polyimide substrates for flexible thin film photovoltaic devices

Energy Technology Data Exchange (ETDEWEB)

Guillen, C.; Herrero, J

2003-05-01

Both frontal and back electrical contacts have been developed onto polyimide sheets (Kapton KJ[reg]) as alternative substrates to the conventional glasses, for application in lightweight and flexible thin film photovoltaic devices. Transparent and conductive indium tin oxide (ITO) thin films have been deposited by r.f.-magnetron sputtering as the frontal electrical contact. On the other hand, Mo, Cr and Ni layers have been prepared by e-gun evaporation for the back electrical connections. ITO films deposited onto polyimide have shown similar optical transmittance and higher electrical conductivity than onto glass substrates. The transmittance decreases and the conductivity increases after heating at 400 sign C in vacuum atmosphere. Mo, Cr and Ni layers deposited onto polyimide showed similar structure and electrical conductivity than onto conventional glasses. The properties of Mo and Cr layers remained unchanged after heating at 400 sign C in selenium atmosphere.

Optimizing the Parameters in Heat Treatment for Achieving High Hardness and Efficient Bending of Thin BS 2014 Aluminium Alloy Sheets

Directory of Open Access Journals (Sweden)

Abirami Priyadarshini B.

2016-05-01

Full Text Available The present work targets in setting a standard heat treatment procedure for obtaining high hardness values of the order of 80 HRB in BS 2014 aluminium alloy sheets of 2mm thick commonly used in aerospace industries. A hardness range of 60HRB to 72HRB is possible in low thickness sheets as stated in the standard BS EN 485-2:2013. Experiments were performed to achieve higher hardness values by controlling the heat treatment temperatures thereby understanding the ageing mechanism of the Al-Cu alloy to a wider extent. The validated process sequence in turn resulted in complications where bending of the sheets resulted in cracking. Further investigation was performed and it was found that the BS 2014 alloy has to be bent within two hours of solution annealing in order to have an efficient bending. The results showed that the natural ageing is so rapid in this alloy, which strengthens the material so quickly by the formation of CuAl2 precipitates, thereby, demanding the bending procedure to be performed before the growth of precipitates becomes dominant.

Production technique for thin undecalcified bone sections suitable for autoradiography

International Nuclear Information System (INIS)

Farnham, J.E.; Schlenker, R.A.

1985-01-01

The production of thin bone sections using power-driven grinding equipment is described. With such equipment, sections can be readily ground to thicknesses between 30 and 40 μm in a rapid and controlled fashion. The yield of usable sections is nearly 100%

XPS analysis of the activation process in non-evaporable getter thin films

CERN Document Server

Lozano, M

2000-01-01

The surface activation process of sputter-coated non-evaporable getter (NEG) thin films based on Ti-Zr and Ti-Zr-V alloys has been studied in situ by means of X-ray photoelectron spectroscopy. After exposure of the NEG thin films to ambient air they become reactivated after a thermal treatment in an ultrahigh vacuum. In our case the films are heated up to ~250 degrees C for 2 h in a base pressure of ~10/sup -9/ Torr. (18 refs).

Logistic characteristics of phonon transport in silicon thin film: the S-curve

Energy Technology Data Exchange (ETDEWEB)

Yilbas, B.S., E-mail: bsyilbas@kfupm.edu.sa; Mansoor, S. Bin

2013-10-01

The logistic characteristics of the averaged heat flux are investigated across the thin film incorporating the S-curve. Temporal behaviour of the heat flux vector is computed using the Boltzmann transport equation. The dispersion relations are introduced to account for the frequency dependent phonon transport across the film. The influence of film width on the characteristics of the averaged heat flux is also examined. It is found that temporal behaviour of the averaged heat flux follows the S-curve. The S-curve characteristics change for different film widths. The time to reach 95% steady value of the averaged heat flux is short for the film with small widths, which is attributed to the ballistic behaviour of phonons in the film.

Logistic characteristics of phonon transport in silicon thin film: the S-curve

International Nuclear Information System (INIS)

Yilbas, B.S.; Mansoor, S. Bin

2013-01-01

The logistic characteristics of the averaged heat flux are investigated across the thin film incorporating the S-curve. Temporal behaviour of the heat flux vector is computed using the Boltzmann transport equation. The dispersion relations are introduced to account for the frequency dependent phonon transport across the film. The influence of film width on the characteristics of the averaged heat flux is also examined. It is found that temporal behaviour of the averaged heat flux follows the S-curve. The S-curve characteristics change for different film widths. The time to reach 95% steady value of the averaged heat flux is short for the film with small widths, which is attributed to the ballistic behaviour of phonons in the film

Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

OpenAIRE

Lee, Youngseok; Oh, Woongkyo; Dao, Vinh Ai; Hussain, Shahzada Qamar; Yi, Junsin

2012-01-01

It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT) solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO) process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get high Voc by lowering the leakage current (I0) which improves the efficie...

A Dual-Plane PIV Study of Turbulent Heat Transfer Flows

Science.gov (United States)

Wernet, Mark P.; Wroblewski, Adam C.; Locke, Randy J.

2016-01-01

Thin film cooling is a widely used technique in turbomachinery and rocket propulsion applications, where cool injection air protects a surface from hot combustion gases. The injected air typically has a different velocity and temperature from the free stream combustion flow, yielding a flow field with high turbulence and large temperature differences. These thin film cooling flows provide a good test case for evaluating computational model prediction capabilities. The goal of this work is to provide a database of flow field measurements for validating computational flow prediction models applied to turbulent heat transfer flows. In this work we describe the application of a Dual-Plane Particle Image Velocimetry (PIV) technique in a thin film cooling wind tunnel facility where the injection air stream velocity and temperatures are varied in order to provide benchmark turbulent heat transfer flow field measurements. The Dual-Plane PIV data collected include all three components of velocity and all three components of vorticity, spanning the width of the tunnel at multiple axial measurement planes.

Enhanced Absorption in Organic Thin-Films from Imprinted Concave Nanostructures

DEFF Research Database (Denmark)

Goszczak, Arkadiusz Jaroslaw; Rubahn, Horst-Günter; Madsen, Morten

2017-01-01

In this work, a rapid, replicable method for imprinting concave nanostructures to be used as functional light-trapping nanostructures in organic thin-films is presented. Porous anodic alumina templates were fabricated both by anodization of thick Al foils and by anodization of submicrometer thin Al...... patterns and used for imprinting of spin coated photoresist on glass substrates. We have investigated semi-periodic and aperiodic imprinted large concave patterns fabricated from rigid masters after anodization of Al in H3PO4. We show that metal covered imprinted concaves show enhancement in absorption...

The influence of heat accumulation on the surface roughness in powder-bed additive manufacturing

International Nuclear Information System (INIS)

Jamshidinia, Mahdi; Kovacevic, Radovan

2015-01-01

The influence of heat accumulation on surface roughness during powder-bed additive manufacturing was investigated. A series of Ti-6Al-4V thin plates were produced by using an identical heat input by electron beam melting® (EBM). Spacing distances of 5 mm, 10 mm, and 20 mm were used. The surface roughness of as-built thin plates was measured using a two-axis profilometer. A numerical model was developed to study the influence of spacing distance on heat accumulation. An inverse relationship between the spacing distance and surface roughness was revealed. The experimental and numerical results showed that the surface quality of buildups could be controlled not only by process parameters, but also by the arrangement of components in the buildup chamber. At a constant spacing distance, an increase in the number of powder layers resulted in the accumulation of more heat between the thin plates. An increase in the spacing distance resulted in an upward translation of the Bearing Area Curve (BAC) toward shallower depths, with a reduced core roughness depth (R k ) and peak height (R pk ). A logarithmic regression equation was established from the experimental data. This equation could be used to predict the surface roughness of parts fabricated by EBM® in the studied range of spacing distances. (paper)

Nonequilibrium temperatures and second-sound propagation along nanowires and thin layers

International Nuclear Information System (INIS)

Jou, D.; Cimmelli, V.A.; Sellitto, A.

2009-01-01

It is shown that the dispersion relation of heat waves along nanowires or thin layers could allow to compare two different definitions of nonequilibrium temperature, since thermal waves are predicted to propagate with different phase speed depending on the definition of nonequilibrium temperature being used. The difference is small, but it could be in principle measurable in nanosystems, as for instance nanowires and thin layers, in a given frequency range. Such an experiment could provide a deeper view on the problem of the definition of temperature in nonequilibrium situations.

Development of Ultrafast Laser Flash Methods for Measuring Thermophysical Properties of Thin Films and Boundary Thermal Resistances

Science.gov (United States)

Baba, Tetsuya; Taketoshi, Naoyuki; Yagi, Takashi

2011-11-01

Reliable thermophysical property values of thin films are important to develop advanced industrial technologies such as highly integrated electronic devices, phase-change memories, magneto-optical disks, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), semiconductor lasers (LDs), flat-panel displays, and power electronic devices. In order to meet these requirements, the National Metrology Institute of Japan of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed ultrafast laser flash methods heated by picosecond pulse or nanosecond pulse with the same geometrical configuration as the laser flash method, which is the standard method to measure the thermal diffusivity of bulk materials. Since these pulsed light heating methods induce one-dimensional heat diffusion across a well-defined length of the specimen thickness, the absolute value of thermal diffusivity across thin films can be measured reliably. Using these ultrafast laser flash methods, the thermal diffusivity of each layer of multilayered thin films and the boundary thermal resistance between the layers can be determined from the observed transient temperature curves based on the response function method. The thermophysical properties of various thin films important for modern industries such as the transparent conductive films used for flat-panel displays, hard coating films, and multilayered films of next-generation phase-change optical disks have been measured by these methods.

[Thin layer agar represents a cost-effective alternative for the rapid diagnosis of multi-drug resistant tuberculosis].

Science.gov (United States)

Hernández-Sarmiento, José M; Martínez-Negrete, Milton A; Castrillón-Velilla, Diana M; Mejía-Espinosa, Sergio A; Mejía-Mesa, Gloria I; Zapata-Fernández, Elsa M; Rojas-Jiménez, Sara; Marín-Castro, Andrés E; Robledo-Restrepo, Jaime A

2014-01-01

Using cost-benefit analysis for comparing the thin-layer agar culture method to the standard multiple proportion method used in diagnosing multidrug-resistant tuberculosis (MDR TB). A cost-benefit evaluation of two diagnostic tests was made at the Corporación para Investigaciones Biológicas (CIB) in Medellín, Colombia. 100 patients were evaluated; 10.8% rifampicin resistance and 14.3% isoniazid resistance were found. A computer-based decision tree model was used for cost-effectiveness analysis (Treeage Pro); the thin-layer agar culture method was most cost-effective, having 100% sensitivity, specificity and predictive values for detecting rifampicin and isoniazid resistance. The multiple proportion method value was calculated as being US$ 71 having an average 49 day report time compared to US$ 18 and 14 days for the thin-layer agar culture method. New technologies have been developed for diagnosing tuberculosis which are apparently faster and more effective; their operating characteristics must be evaluated as must their effectiveness in terms of cost-benefit. The present study established that using thin-layer agar culture was cheaper, equally effective and could provide results more quickly than the traditional method. This implies that a patient could receive MDR TB treatment more quickly.

Rapid preparation of α-FeOOH and α-Fe2O3 nanostructures by microwave heating and their application in electrochemical sensors

International Nuclear Information System (INIS)

Marinho, J.Z.; Montes, R.H.O.; Moura, A.P. de; Longo, E.; Varela, J.A.; Munoz, R.A.A.; Lima, R.C.

2014-01-01

Graphical abstract: - Highlights: • Simple microwave method leads to the rapid formation of the goethite and hematite. • Homogenous nucleation and growth of particles are controlled by synthesis time. • Modified electrode with α-FeOOH nanoplates improved the electrochemical response. • The sample is directly heated by microwaves and its crystallization is accelerated. • Fe 3+ nanostructures are promising for development of electrochemical sensors. - Abstract: α-FeOOH (goethite) and α-Fe 2 O 3 (hematite) nanostructures have been successfully synthesized using the microwave-assisted hydrothermal (MAH) method and by the rapid burning in a microwave oven of the as-prepared goethite, respectively. The orthorhombic α-FeOOH to rhombohedralα-Fe 2 O 3 structural transformation was observed by X-ray diffraction (XRD) and Raman spectroscopy results. Plates-like α-FeOOH prepared in 2 min and rounded and quasi-octahedral shaped α-Fe 2 O 3 particles obtained in 10 min were observed using field emission gun scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The use of microwave heating allowed iron oxides to be prepared with shorter reaction times when compared to other synthesis methods. α-FeOOH nanoplates were incorporated into graphite-composite electrodes, which presented electrocatalytic properties towards the electrochemical oxidation of ascorbic acid in comparison with unmodified electrodes. This result demonstrates that such α-FeOOH nanostructures are very promising chemical modifiers for the development of improved electrochemical sensors

In-situ X-Ray Analysis of Rapid Thermal Processing for Thin-Film Solar Cells: Closing the Gap between Production and Laboratory Efficiency

Energy Technology Data Exchange (ETDEWEB)

Toney, Michael F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); van Hest, Maikel F. A. M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-02-21

For materials synthesis, it is well known that the material final state may not reach equilibrium and depends on the synthetic process. In particular, processes that quickly remove the available energy from the material may leave it in a metastable state and the metastability may actually impart desirable functional properties. By its very nature, Rapid thermal processing (RTP) is ideally suited to produce such metastable materials. However, metastability and the dynamics of reaching a metastable state are poorly understood, since this is best accomplished through in situ monitoring. In this regard, RTP is particularly challenging as the processing time are very short (seconds to minutes). As a result, there is only poor understanding, and hence use, of RTP in industry. This is potentially a cost-increasing limitation, because RTP can decrease cost by decreasing processing time, and as such, increase throughput and decrease the total thermal budget of processing - a significant cost. RTP is already being used for key processing steps in PV technologies. With silicon wafer PV, it is used for establishing electrical contact between the Ag metal grid and the silicon (known as firing). In this process, a silicon wafer with deposited metal/frit in a grid pattern is heated rapidly to temperatures between 750 and 800 ºC. The processing time when the temperature is held above 600ºC is short (<5 seconds). This process has historically been optimized empirically and it is unclear how the thermal processing affects formation of the final contact between the metal and the silicon. In the case of thin-film PV, RTP has been demonstrated in the process of making absorber layers, i.e. CIGS and CZTS. Use of RTP can reduce the processing time from 10s of minutes to seconds, reducing the thermal budget and increasing the throughput significantly. The conversion from precursor material to final PV material is not well understood, and most of the process optimization is done

Zirconia thin films from aqueous precursors: Processing, microstructural development, and epitaxial growth

International Nuclear Information System (INIS)

Miller, K.T.

1991-01-01

Thin films of ZrO 2 (Y 2 O 3 ) were prepared from aqueous salt precursors by spin coating. Films were pyrolyzed to produce porous polycrystalline thin films of 5-10 nm grain size. Subsequent microstructural development depends greatly upon the nature of the substrate. Upon randomly oriented sapphire, the films initially sintered to full density; further heat treatment and grain growth causes these films to break into interconnected islands and finally isolated particles. Thermodynamic calculations predict that breakup is energetically favorable when the grain-size film-thickness ratio exceeds a critical value. Upon basal-plane-oriented sapphire, grain growth and breakup prefer the (100) oriented grains, presumably because this orientation is a special interface of low energy. The isolated, oriented grains produced by film breakup act as seeds for the growth of newly deposited material. Upon (100) cubic zirconia, true epitaxial films develop. Epitaxial growth was observed for lattice mismatches up to 1.59%. Growth proceeds from a fine epitaxial layer which is produced during the initial stages of heat treatment, consuming the porous polycrystalline material and producing a dense epitaxial thin film whose misfit is accommodated by a combination of film strain and misfit dislocations

Magnetic structures in ultra-thin Holmium films: Influence of external magnetic field

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, L.J. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59600-900, RN (Brazil); Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró 59625-620, RN (Brazil); Mello, V.D. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró 59625-620, RN (Brazil); Anselmo, D.H.A.L. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59600-900, RN (Brazil); Vasconcelos, M.S., E-mail: mvasconcelos@ect.ufrn.br [Escola de Ciência e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil)

2015-03-01

We address the magnetic phases in very thin Ho films at the temperature interval between 20 K and 132 K. We show that slab size, surface effects and magnetic field due to spin ordering impact significantly the magnetic phase diagram. Also we report that there is a relevant reduction of the external field strength required to saturate the magnetization and for ultra-thin films the helical state does not form. We explore the specific heat and the susceptibility as auxiliary tools to discuss the nature of the phase transitions, when in the presence of an external magnetic field and temperature effects. The presence of an external field gives rise to the magnetic phase Fan and the spin-slip structures. - Highlights: • We analyze the magnetic phases of very thin Ho films in the temperature interval 20–132 K. • We show that slab size, etc. due to spin ordering may impact the magnetic phase diagram. • All magnetic phase transitions, for strong magnetic fields, are marked by the specific heat. • The presence of an external field gives rise to the magnetic phase Fan and the spin-slip one.

Formation of thermal fatigue cracks in periodic rapid quenching of metal

Energy Technology Data Exchange (ETDEWEB)

Ots, A [Tallinn Technical University, Thermal Engineering Department, Tallinn (Estonia)

1999-12-31

Water lancing is an effective technique for cleaning boiler heating surfaces from ash deposits by burning low-grade fuels with complicated composition of mineral matter. In water cleaning cycles of boiler`s heat transfer surfaces due to rapid quenching destruction of corrosion protective oxide film and formation of thermal fatigue cracks on the outer surface of the tube`s metal occur. The criterion of the thermal fatigue cracks` formation and their growth intensity depend on the character of temperature field in the tube`s metal outer layer. The solution of non-stationary heat conductivity equation for metal rapid quenching conditions is given. The convective heat transfer coefficients from hot metal surface to water jet were established experimentally. Thermal fatigue crack growth intensity was investigated in real boilers` heat transfer surfaces` tubes as well as in laboratory conditions. The formula for predicting thermal fatigue cracks` depth depending on the number of cleaning cycles. (orig.) 5 refs.

Formation of thermal fatigue cracks in periodic rapid quenching of metal

Energy Technology Data Exchange (ETDEWEB)

Ots, A. [Tallinn Technical University, Thermal Engineering Department, Tallinn (Estonia)

1998-12-31

Water lancing is an effective technique for cleaning boiler heating surfaces from ash deposits by burning low-grade fuels with complicated composition of mineral matter. In water cleaning cycles of boiler`s heat transfer surfaces due to rapid quenching destruction of corrosion protective oxide film and formation of thermal fatigue cracks on the outer surface of the tube`s metal occur. The criterion of the thermal fatigue cracks` formation and their growth intensity depend on the character of temperature field in the tube`s metal outer layer. The solution of non-stationary heat conductivity equation for metal rapid quenching conditions is given. The convective heat transfer coefficients from hot metal surface to water jet were established experimentally. Thermal fatigue crack growth intensity was investigated in real boilers` heat transfer surfaces` tubes as well as in laboratory conditions. The formula for predicting thermal fatigue cracks` depth depending on the number of cleaning cycles. (orig.) 5 refs.

Development of wear resistant zirconium oxide thin films on stainless steel substrates

International Nuclear Information System (INIS)

Then, I.K.; Mujahid, M.; Zhang, B.

2005-01-01

The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 μm in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650 C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced. (orig.)

Development of wear resistant zirconium oxide thin films on stainless steel substrates

Energy Technology Data Exchange (ETDEWEB)

Then, I.K.; Mujahid, M. [School of Materials Engineering, Nanyang Technological Univ. (Singapore); Zhang, B. [Dou Yee Technologies Pte Ltd, Bedok Industrial Park C (Singapore)

2005-07-01

The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 {mu}m in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650 C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced. (orig.)

Overhaul of the heat exchanger in JRR-3

International Nuclear Information System (INIS)

Ouchi, Yasuhiro; Kawamata, Satoshi; Taguchi, Yuji; Kamiishi, Eigo; Koda, Nobuyuki

2013-01-01

In JRR-3, heat exchangers are installed in the cooling system equipment to remove the heat generated in the nuclear reactor, For the heat exchangers, overhaul inspection based on the JRR-3 reactor facility maintenance plan, as well as the inspection and maintenance based on reactor facility security provisions and JRR-3 operation guidelines are systematically conducted. Considering the results of overhaul inspection, the second overhaul inspection was applied to the primary coolant heat exchanger. The thinning of heat transfer tubes is within judgment standards with little effects of aging, which verified their soundness. From the fact that the effects of corrosion have been confirmed on the inside of the water chamber, repair work through overlay welding or the like is planned in the next overhaul. As for heavy water heat exchanger and the spent fuel pool water heat exchanger, it is planned to conduct the second overhaul inspection in FY2013 to confirm their soundness. (A.O.)

Harnessing Thin-Film Continuous-Flow Assembly Lines.

Science.gov (United States)

Britton, Joshua; Castle, Jared W; Weiss, Gregory A; Raston, Colin L

2016-07-25

Inspired by nature's ability to construct complex molecules through sequential synthetic transformations, an assembly line synthesis of α-aminophosphonates has been developed. In this approach, simple starting materials are continuously fed through a thin-film reactor where the intermediates accrue molecular complexity as they progress through the flow system. Flow chemistry allows rapid multistep transformations to occur via reaction compartmentalization, an approach not amenable to using conventional flasks. Thin film processing can also access facile in situ solvent exchange to drive reaction efficiency, and through this method, α-aminophosphonate synthesis requires only 443 s residence time to produce 3.22 g h(-1) . Assembly-line synthesis allows unprecedented reaction flexibility and processing efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of excitation intensity on the photocurrent response of thin film silicon solar modules

Science.gov (United States)

Kim, Q.; Shumka, A.; Trask, J.

1986-01-01

Photocurrent responses of amorphous thin film silicon solar modules at room temperature were studied at different excitation intensities using various monochromatic light sources. Photocurrent imaging techniques have been effectively used to locate rapidly, and non-destructively, failure and defect sites in the multilayer thin film device. Differences observed in the photocurrent response characteristics for two different cells in the same amorphous thin film silicon solar module suggest the possibility of the formation of dissimilarly active devices, even though the module is processed in the same fabrication process. Possible mechanisms are discussed.

Incremental heating of Bishop Tuff sanidine reveals preeruptive radiogenic Ar and rapid remobilization from cold storage

Science.gov (United States)

Andersen, Nathan L.; Jicha, Brian R.; Singer, Brad S.; Hildreth, Wes

2017-11-01

Accurate and precise ages of large silicic eruptions are critical to calibrating the geologic timescale and gauging the tempo of changes in climate, biologic evolution, and magmatic processes throughout Earth history. The conventional approach to dating these eruptive products using the 40Ar/39Ar method is to fuse dozens of individual feldspar crystals. However, dispersion of fusion dates is common and interpretation is complicated by increasingly precise data obtained via multicollector mass spectrometry. Incremental heating of 49 individual Bishop Tuff (BT) sanidine crystals produces 40Ar/39Ar dates with reduced dispersion, yet we find a 16-ky range of plateau dates that is not attributable to excess Ar. We interpret this dispersion to reflect cooling of the magma reservoir margins below ˜475 °C, accumulation of radiogenic Ar, and rapid preeruption remobilization. Accordingly, these data elucidate the recycling of subsolidus material into voluminous rhyolite magma reservoirs and the effect of preeruptive magmatic processes on the 40Ar/39Ar system. The youngest sanidine dates, likely the most representative of the BT eruption age, yield a weighted mean of 764.8 ± 0.3/0.6 ka (2σ analytical/full uncertainty) indicating eruption only ˜7 ky following the Matuyama‑Brunhes magnetic polarity reversal. Single-crystal incremental heating provides leverage with which to interpret complex populations of 40Ar/39Ar sanidine and U-Pb zircon dates and a substantially improved capability to resolve the timing and causal relationship of events in the geologic record.

Transparent thin-film transistor exploratory development via sequential layer deposition and thermal annealing

International Nuclear Information System (INIS)

Hong, David; Chiang, Hai Q.; Presley, Rick E.; Dehuff, Nicole L.; Bender, Jeffrey P.; Park, Cheol-Hee; Wager, John F.; Keszler, Douglas A.

2006-01-01

A novel deposition methodology is employed for exploratory development of a class of high-performance transparent thin-film transistor (TTFT) channel materials involving oxides composed of heavy-metal cations with (n - 1)d 10 ns 0 (n ≥ 4) electronic configurations. The method involves sequential radio-frequency sputter deposition of thin, single cation oxide layers and subsequent post-deposition annealing in order to obtain a multi-component oxide thin film. The viability of this rapid materials development methodology is demonstrated through the realization of high-performance TTFTs with channel layers composed of zinc oxide/tin oxide, and tin oxide/indium oxide

Measurement of Two-Phase Flow and Heat Transfer Parameters using Infrared Thermometry

Science.gov (United States)

Kim, Tae-Hoon; Kommer, Eric; Dessiatoun, Serguei; Kim, Jungho

2012-01-01

A novel technique to measure heat transfer and liquid film thickness distributions over relatively large areas for two-phase flow and heat transfer phenomena using infrared (IR)thermometry is described. IR thermometry is an established technology that can be used to measure temperatures when optical access to the surface is available in the wavelengths of interest. In this work, a midwave IR camera (3.6-5.1 microns) is used to determine the temperature distribution within a multilayer consisting of a silicon substrate coated with a thin insulator. Since silicon is largely transparent to IR radiation, the temperature of the inner and outer walls of the multilayer can be measured by coating selected areas with a thin, IR opaque film. If the fluid used is also partially transparent to IR, the flow can be visualized and the liquid film thickness can be measured. The theoretical basis for the technique is given along with a description of the test apparatus and data reduction procedure. The technique is demonstrated by determining the heat transfer coefficient distributions produced by droplet evaporation and flow boiling heat transfer.

Role of heat treatment on structural and optical properties of thermally evaporated Ga{sub 10}Se{sub 81}Pb{sub 9} chalcogenide thin films

Energy Technology Data Exchange (ETDEWEB)

El-Sebaii, A.A., E-mail: ahmedelsebaii@yahoo.com [Department of Physics, Faculty of Science, King Abdulaziz University, 80203 Jeddah 21589 (Saudi Arabia); Khan, Shamshad A. [Department of Physics, St. Andrews College, Gorakhpur 273001 (India); Al-Marzouki, F.M.; Faidah, A.S.; Al-Ghamdi, A.A. [Department of Physics, Faculty of Science, King Abdulaziz University, 80203 Jeddah 21589 (Saudi Arabia)

2012-08-15

Amorphous chalcogenides, based on Se, have become materials of commercial importance and were widely used for optical storage media. The present work deals with the structural and optical properties of Ga{sub 10}Se{sub 81}Pb{sub 9} ternary chalcogenide glass prepared by melt quenching technique. The glass transition, crystallization and melting temperatures of the synthesized glass were measured by non-isothermal DSC measurements at a constant heating rate of 30 K/min. Thin films of thickness 4000 A were prepared by thermal evaporation techniques on glass/Si (1 0 0) wafer substrate. These thin films were thermally annealed for two hours at three different annealing temperatures of 345, 360 and 375 K, which were in between the glass transition and crystallization temperatures of the Ga{sub 10}Se{sub 81}Pb{sub 9} glass. The structural, morphological and optical properties of as-prepared and annealed thin films were studied. Analysis of the optical absorption data showed that the rules of the non-direct transitions predominate. It was also found that the optical band gap decreases while the absorption coefficient, refractive index and extinction coefficient increase with increasing the annealing temperature. Due to the higher values of absorption coefficient and annealing dependence of the optical band gap and optical constants, the investigated material could be used for optical storage. - Highlights: Black-Right-Pointing-Pointer Annealing effect on structure and optical band gap has been investigated. Black-Right-Pointing-Pointer The amorphous nature has been verified by x-ray diffraction and DSC measurements. Black-Right-Pointing-Pointer Thermal annealing causes a decrease in optical band gap in Ga{sub 10}Se{sub 81}Pb{sub 9} thin films. Black-Right-Pointing-Pointer The decrease in optical band gap can be interpreted on the basis of amorphous-crystalline phase transformation. Black-Right-Pointing-Pointer Optical absorption data showed that the rules of the non

Macroscopic and microscopic determinations of residual stresses in thin oxide dispersion strengthened steel tubes

International Nuclear Information System (INIS)

Bechade, J.L.; Toualbi, L.; Bosonnet, S.; Carlan, Y. de; Castelnau, O.

2014-01-01

To improve the efficiency of components operating at high temperatures, many efforts are deployed to develop new materials. Oxide Dispersion Strengthened (ODS) materials could be used for heat exchangers or cladding tubes for the new GENIV nuclear reactors. This type of materials are composed with a metallic matrix (usually iron base alloy for nuclear applications or nickel base alloy for heat exchangers) reinforced by a distribution of nano-oxides. They are obtained by powder metallurgy and mechanical alloying. The creep resistance of these materials is excellent, and they usually exhibit a high tensile strength at room temperature. Depending on the cold working and/or the heat treatments, several types of microstructure can be obtained: recrystallised, stress relieved. One of the key challenges is to transform ODS materials into thin tubes (up to 500 microns thick) within a robust fabrication route while keeping the excellent mechanical properties. To prevent cracking during the process or to obtain a final product with low residual stresses, it is important to quantify the effect of the heat treatments on the release of internal stresses. The aim of this study is to show how residual stresses can be determined on different thin tubes using two complementary approaches: (i) macroscopic stresses determination in the tube using beam theory (small cuts along the longitudinal and circumferential directions and measurements of the deflection), (ii) stress determination from x-ray diffraction analyses (surface analyses, using 'sin"2ψ' method with different hypothesis). Depending on the material and the heat treatment, residual stresses vary dramatically and can reach 800 MPa which is not far from the yield stress; comparisons between both methods are performed and suggestions are given in order to optimize the thermo-mechanical treatment of thin ODS tubes. (authors)

The inaccuracy of heat transfer characteristics of insulated and non-insulated circular duct while neglecting the influence of heat radiation

International Nuclear Information System (INIS)

Hsien, T.-L.; Wong, K.-L.; Yu, S.-J.

2009-01-01

The non-insulated and insulated ducts are commonly applied in the industries and various buildings, because the heat radiation equation contains the 4th order exponential of temperature which is very complicate in calculations. Most heat transfer experts recognized from their own experiences that the heat radiation effect can be ignored due to the small temperature difference between insulated and non-insulated surface and surroundings. This paper studies in detail to check the inaccuracies of heat transfer characteristics non-insulated and insulated duct by comparing the results between considering and neglecting heat radiation effect. It is found that neglecting the heat radiation effect is likely to produce large errors of non-insulated and thin-insulated ducts in situations of ambient air with low external convection heat coefficients and larger surface emissivity, especially while the ambient air temperature is different from that of surroundings and greater internal fluid convection coefficients. It is also found in this paper that using greater duct surface emissivity can greatly improve the heat exchanger effect and using smaller insulated surface emissivity can obtain better insulation.

Improvement of Self-Heating of Indium Gallium Zinc Aluminum Oxide Thin-Film Transistors Using Al2O3 Barrier Layer

Science.gov (United States)

Jian, Li-Yi; Lee, Hsin-Ying; Lin, Yung-Hao; Lee, Ching-Ting

2018-02-01

To study the self-heating effect, aluminum oxide (Al2O3) barrier layers of various thicknesses have been inserted between the channel layer and insulator layer in bottom-gate-type indium gallium zinc aluminum oxide (IGZAO) thin-film transistors (TFTs). Each IGZAO channel layer was deposited on indium tin oxide (ITO)-coated glass substrate by using a magnetron radiofrequency cosputtering system with dual targets composed of indium gallium zinc oxide (IGZO) and Al. The 3 s orbital of Al cation provided an extra transport pathway and widened the conduction-band bottom, thus increasing the electron mobility of the IGZAO films. The Al-O bonds were able to sustain the oxygen stability of the IGZAO films. The self-heating behavior of the resulting IGZAO TFTs was studied by Hall measurements on the IGZAO films as well as the electrical performance of the IGZAO TFTs with Al2O3 barrier layers of various thicknesses at different temperatures. IGZAO TFTs with 50-nm-thick Al2O3 barrier layer were stressed by positive gate bias stress (PGBS, at gate-source voltage V GS = 5 V and drain-source voltage V DS = 0 V); at V GS = 5 V and V DS = 10 V, the threshold voltage shifts were 0.04 V and 0.2 V, respectively, much smaller than for the other IGZAO TFTs without Al2O3 barrier layer, which shifted by 0.2 V and 1.0 V when stressed under the same conditions.

A rapidly equilibrating, thin film, passive water sampler for organic contaminants; characterization and field testing

Energy Technology Data Exchange (ETDEWEB)

St George, Tiffany [Department of Marine Science, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 (United States); Department of Science, United States Coast Guard Academy, 27 Mohegan Ave., New London, CT 06320 (United States); Vlahos, Penny, E-mail: penny.vlahos@uconn.ed [Department of Chemistry, University of Connecticut, 55 Eagleville Road, Storrs, CT 06269 (United States); Department of Marine Science, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 (United States); Harner, Tom [Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada); Helm, Paul [Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Rd, Toronto, Ontario M9P 3V6 (Canada); Wilford, Bryony [Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada)

2011-02-15

Improving methods for assessing the spatial and temporal resolution of organic compound concentrations in marine environments is important to the sustainable management of our coastal systems. Here we evaluate the use of ethylene vinyl acetate (EVA) as a candidate polymer for thin-film passive sampling in waters of marine environments. Log K{sub EVA-W} partition coefficients correlate well (r{sup 2} = 0.87) with Log K{sub OW} values for selected pesticides and polychlorinated biphenyls (PCBs) where Log K{sub EVA-W} = 1.04 Log K{sub OW} + 0.22. EVA is a suitable polymer for passive sampling due to both its high affinity for organic compounds and its ease of coating at sub-micron film thicknesses on various substrates. Twelve-day field deployments were effective in detecting target compounds with good precision making EVA a potential multi-media fugacity meter. - Research highlights: Calibration and field testing of a thin-film passive sampler in marine systems. Ethylene vinyl acetate (EVA) is effective for a wide spectrum of organic compounds. EVA performs with high precision and reproducibility. EVA is effective in marine systems at environmentally relevant concentrations. EVA is recommended as a multi-media fugacity meter for environmental applications. - An ethylene vinyl acetate (EVA), thin-film passive sampler for the detection of organic compounds in marine environments is calibrated and field tested.

The effect of heat generation in inclined slats on the natural convective heat transfer from an isothermal heated vertical plate

International Nuclear Information System (INIS)

Oosthuizen, P.H.; Sun, L.; Naylor, D.

2003-01-01

Natural convective heat transfer from a wide heated vertical isothermal plate with adiabatic surfaces above and below the heated surface has been considered. There are a series of equally spaced vertical thin, flat surfaces (termed 'slats') near the heated surface, these surfaces being, in general, inclined to the heated surface. There is, in general, a uniform heat generation in the slats. The slats are pivoted about their centre-point and thus as their angle is changed, the distance of the tip of the slat from the plate changes. The situation considered is an approximate model of a window with a vertical blind, the particular case where the window is hotter than the room air being considered. The heat generation in the slats in this situation is the result of solar radiation passing through the window and falling on and being absorbed by the slats of the blind. The flow has been assumed to be laminar and steady. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces. The governing equations have been written in dimensionless form and the resulting dimensionless equations have been solved using a commercial finite-element package. The solution has the following parameters: (1) the Rayleigh number (2) the Prandtl number (3) the dimensionless heat generation rate in the slats per unit frontal area (4) the dimensionless distance of the slat center point (the pivot point) from the surface (5) the dimensionless slat size (6) the dimensionless slat spacing (7) the angle of inclination of the slats. Because of the application that motivated the study, results have only been obtained for a Prandtl number of 0.7. The effect of the other dimensionless variables on the mean dimensionless heat transfer rate from the heated vertical surface has been examined. (author)

Optical approach to thermopower and conductivity measurements in thin-film semiconductors

International Nuclear Information System (INIS)

Dersch, H.; Amer, N.M.

1984-01-01

An optical beam deflection technique is applied to measure the Joule and Peltier heat generated by electric currents through thin-film semiconductors. The method yields a spatially resolved conductivity profile and allows the determination of Peltier coefficients. Results obtained on doped hydrogenated amorphous silicon films are presented

Homogenization and dimension reduction of filtration combustion in heterogeneous thin layers

NARCIS (Netherlands)

Fatima, T.; Ijioma, E.R.; Ogawa, T.; Muntean, A.

2014-01-01

We study the homogenization of a reaction-diffusion-convection system posed in an e-periodic d-thin layer made of a two-component (solid-air) composite material. The microscopic system includes heat flow, diffusion and convection coupled with a nonlinear surface chemical reaction. We treat two

A thin gold coated hydrogen heat pipe -cryogenic target for external experiments at cosy

International Nuclear Information System (INIS)

Abdel-Bary, M.; Abdel-Samad, S.; Elawadi, G.A.; Kilian, K.; Ritman, J.

2008-01-01

A gravity assisted Gold Coated Heat Pipe (GCHP) with 5-mm diameter has been developed and tested to cool a liquid hydrogen target for external beam experiments at COSY. The need for a narrow target diameter leads us to study the effect of reducing the heat pipe diameter to 5 mm instead of 7 mm, to study the effect of coating the external surface of the heat pipe by a polished gold layer (to decrease the radiation heat load), and to study the effect of using the heat pipe without using 20 layers super isolation around it (aluminized Mylar foil) to keep the target diameter as small as possible. The developed gold coated heat pipe was tested with 20 layers of super isolation and without. The operating characteristics for both conditions were compared to show the advantages and disadvantages

X-ray-induced thinning of 3He and 3He/4He mixture films

International Nuclear Information System (INIS)

Penanen, Konstantin; Fukuto, Masafumi; Silvera, Isaac F.; Pershan, Peter

2000-01-01

Films of isotopic mixtures of helium have been studied using x-ray specular reflectivity techniques. In contrast with superfluid 4 He films, x-ray exposure causes a reduction in the thickness of 4 He films above the superfluid transition as well as films of pure 3 He and 3 He/ 4 He mixtures. One proposed model that could account for this effect is a charging model, in which thinning is caused by electrostatic pressure of free charges that accumulate on the helium surface. Unfortunately, this model is not fully consistent with all of the experimental observations. A localized heating model, in which indirect heating of the film causes it to thin would explain the data if there were dissipative film flow in the 3 He/ 4 He mixtures at temperatures where the bulk is superfluid. We argue that various published experimental results suggest such an effect. In this model, film thinning data for dilute 3 He/ 4 He films indicates dissipation that is linear in 3 He content of the film over two orders of magnitude

Rapid thermal pulse annealing

International Nuclear Information System (INIS)

Miller, M.G.; Koehn, B.W.; Chaplin, R.L.

1976-01-01

Characteristics of recovery processes have been investigated for cases of heating a sample to successively higher temperatures by means of isochronal annealing or by using a rapid pulse annealing. A recovery spectra shows the same features independent of which annealing procedure is used. In order to determine which technique provides the best resolution, a study was made of how two independent first-order processes are separated for different heating rates and time increments of the annealing pulses. It is shown that the pulse anneal method offers definite advantages over isochronal annealing when annealing for short time increments. Experimental data by means of the pulse anneal techniques are given for the various substages of stage I of aluminium. (author)

AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films for solar cell applications

Energy Technology Data Exchange (ETDEWEB)

González, J.O. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); Shaji, S.; Avellaneda, D. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León, México (Mexico); Castillo, A.G.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); and others

2013-05-15

Highlights: ► AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films were formed by heating Na{sub 2}SeSO{sub 3} dipped Sb{sub 2}S{sub 3}/Ag layers. ► S/Se ratio was varied by changing the dipping time in Na{sub 2}SeSO{sub 3} solution. ► Characterized the films using XRD, XPS, SEM, Optical and electrical measurements. ► Band gap engineering of 1−1.1 eV for x = 0.51 and 0.52 respectively. ► PV Glass/FTO/CdS/AgSb(S{sub x}Se{sub 1−x}){sub 2}/C were prepared showing V{sub oc} = 410 mV, J{sub sc} = 5.7 mA/cm{sup 2}. - Abstract: Silver antimony sulfoselenide (AgSb(S{sub x}Se{sub 1−x}){sub 2}) thin films were prepared by heating glass/Sb{sub 2}S{sub 3}/Ag layers after selenization using sodium selenosulphate solution. First, Sb{sub 2}S{sub 3} thin films were deposited on glass substrates from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}. Then Ag thin films were thermally evaporated onto glass/Sb{sub 2}S{sub 3}, followed by selenization by dipping in an acidic solution of Na{sub 2}SeSO{sub 3}. The duration of selenium dipping was varied as 30 min and 2 h. The heating condition was at 350 °C for 1 h in vacuum. Analysis of X-ray diffraction pattern of the thin films formed after heating showed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Morphology and elemental analysis were done by scanning electron microscopy and energy dispersive X-ray detection. Depth profile of composition of the thin films was performed by X-ray Photoelectron Spectroscopy. The spectral study showed the presence of Ag, Sb, S, and Se, and the corresponding binding energy analysis confirmed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Photovoltaic structures (PV) were prepared using AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films as absorber and CdS thin films as window layers on FTO coated glass substrates. The PV structures were heated at 60–80 °C in air for 1 h to improve ohmic contact. Analysis of J–V characteristics of the PV structures showed V

Shivering and rewarming after cardiac surgery: comparison of ventilator circuits with humidifier and heated wires to heat and moisture exchangers.

Science.gov (United States)

McEvoy, M T; Carey, T J

1995-07-01

Detrimental physiologic effects of shivering in the cardiac surgery patient have been well documented. Rewarming techniques have been compared, with noted differences in the incidence of shivering. Ventilator circuits have not been examined independently from other rewarming variables. To compare heated wire humidification circuits with heat and moisture exchanger circuits on the incidence of shivering and speed and pattern of rewarming in mechanically ventilated patients. A prospective, descriptive, correlational study was done on 140 adult cardiac surgery patients in a university teaching medical center. All subjects underwent cardiac surgical procedures with hypothermic cardiopulmonary bypass. Subjects were randomized to humidified, heated wire circuits (n = 70) or heat and moisture exchanger circuits (n = 70). Heated water blankets were used on all patients. Mean intensive care unit admission temperature was 35.28 degrees C. No statistical differences were found in preoperative, demographic, or operative course data between treatment and control groups. Shivering was more common in the heat and moisture exchanger group than in the heated wire group. In our analysis, the only variable associated with shivering was the type of ventilator circuit. Patients using heated wire systems rewarmed more rapidly and had significantly higher temperatures than did patients using heat and moisture exchangers. These data suggest that use of heated wire humidified ventilator circuits with heated water blankets in adult cardiac surgery patients significantly reduces the incidence of shivering and results in a more rapid return to normothermia.

Optimization of the energy resolution and of the radioactive background rejection for ionization-heat detectors equipped with thermometric thin films for the direct WIMPs detection

International Nuclear Information System (INIS)

Dolgorouky, Y.W.

2008-09-01

The EDELWEISS experiment aims at the direct detection of WIMPs as possible candidates for dark matter. It uses heat-and-ionization detectors that can discriminate these particles from the radioactive background. To date, this method is limited by events with incomplete charge collection that occur just beneath the detectors electrodes. In order to identify and reject these undesirable events, we have developed detectors equipped with thin films used both as thermometers - and hence sensitive to the transient athermal regime - and as electrodes for the charge collection. This thesis focuses on the optimization of such thin films regarding surface events rejection and on the modelling of the physical processes enabling this identification. The optimization must both maximize the fiducial volume and conserve an energy resolution such that the recoil energy threshold is of the order of 30 keV. Our work explores four generations of detectors each of which corresponds to successive evolutions in their conception. In all cases, the electrode-thermometer is an amorphous Anderson insulator NbSi thin film polarized by two interleaved comb-shaped niobium electrodes. In spite of constant progress in the successive detectors performances, the latest generation does not display the performances required for the EDELWEISS II experiment. Our work has shown the difficulty of the transient thermal signal modelling due to the complex contribution of the charge collection. This works has lead to new ideas regarding the detectors configuration, so that the athermal regime can be optimized to enhance both the rejection capability and the resolution. (author)

Determination of ferulic acid and related compounds by thin layer ...

African Journals Online (AJOL)

The analysis of certain phenolic compounds from plants, and their chemical transformation with microorganisms or isolated enzymes, has application in the food and pharmaceutical industry. The rapid quantitative estimation of ferulic acid by thin layer chromatography is described by measurement of the area of the ...

Pulsed laser induced heat transfer from a phthalocyanine-based thin film to a Bi, Al-substituted DyIG substrate: photothermal demagnetization observed by magnetic circular dichroism and numerical analysis.

Science.gov (United States)

Karasawa, Masanobu; Ishii, Kazuyuki

2018-05-03

We have investigated the demagnetization of a ferrimagnetic substrate, Bi, Al-substituted dysprosium iron garnet (Bi0.8Dy2.2Fe4.3Al0.7O12), based on selective pulsed laser irradiation of a molecular thin film consisting of μ-oxo-bis[hydroxyl{2,9(or 10),16(or 17),23(or 24)-tetra-tert-butylphthalocyanato}silicon] ((SiPc)2) and poly(vinylidene fluoride), and succeeded in reproducing photothermal energy transfer from a molecular thin film to an inorganic magnetic substrate in a submicrometer-order and a submicrosecond time scale using numerical analysis. After the instant temperature rise due to nanosecond pulsed laser irradiation of the (SiPc)2-based film, followed by heat transfer from the film to the neighboring magnetic substrate, demagnetization of the magnetic substrate was spectroscopically monitored by the decrease in its magnetic circular dichroism (MCD) intensity. The MCD intensity decreased with increasing pulsed laser energy, which reflects the fact that the submicrometer-order region of the substrate was demagnetized as a result of temperature rise reaching high Curie temperature. This heat transfer phenomenon resulting in the demagnetization of the magnetic substrate was numerically analyzed in a submicrometer-order and a submicrosecond time scale using the finite difference method: the demagnetized regions were calculated to be the same order of magnitude as those experimentally evaluated. These results would provide a more detailed understanding of photothermal energy transfer in organic-inorganic hybrid materials, which would be useful for developing photofunctional materials.

Development of Amorphous/Microcrystalline Silicon Tandem Thin-Film Solar Modules with Low Output Voltage, High Energy Yield, Low Light-Induced Degradation, and High Damp-Heat Reliability

Directory of Open Access Journals (Sweden)

Chin-Yi Tsai

2014-01-01

Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film solar modules with low output voltage, high energy yield, low light-induced degradation, and high damp-heat reliability were successfully designed and developed. Several key technologies of passivation, transparent-conducting-oxide films, and cell and segment laser scribing were researched, developed, and introduced into the production line to enhance the performance of these low-voltage modules. A 900 kWp photovoltaic system with these low-voltage panels was installed and its performance ratio has been simulated and projected to be 92.1%, which is 20% more than the crystalline silicon and CdTe counterparts.

APCVD hexagonal boron nitride thin films for passive near-junction thermal management of electronics

Science.gov (United States)

KC, Pratik; Rai, Amit; Ashton, Taylor S.; Moore, Arden L.

2017-12-01

The ability of graphene to serve as an ultrathin heat spreader has been previously demonstrated with impressive results. However, graphene is electrically conductive, making its use in contact with electronic devices problematic from a reliability and integration perspective. As an alternative, hexagonal boron nitride (h-BN) is a similarly structured material with large in-plane thermal conductivity but which possesses a wide band gap, thereby giving it potential to be utilized for directing contact, near-junction thermal management of electronics without shorting or the need for an insulating intermediate layer. In this work, the viability of using large area, continuous h-BN thin films as direct contact, near-junction heat spreaders for electronic devices is experimentally evaluated. Thin films of h-BN several square millimeters in size were synthesized via an atmospheric pressure chemical vapor deposition (APCVD) method that is both simple and scalable. These were subsequently transferred onto a microfabricated test device that simulated a multigate transistor while also allowing for measurements of the device temperature at various locations via precision resistance thermometry. Results showed that these large-area h-BN films with thicknesses of 77-125 nm are indeed capable of significantly lowering microdevice temperatures, with the best sample showing the presence of the h-BN thin film reduced the effective thermal resistance by 15.9% ± 4.6% compared to a bare microdevice at the same power density. Finally, finite element simulations of these experiments were utilized to estimate the thermal conductivity of the h-BN thin films and identify means by which further heat spreading performance gains could be attained.

Thermal expansion coefficient and thermomechanical properties of SiN(x) thin films prepared by plasma-enhanced chemical vapor deposition.

Science.gov (United States)

Tien, Chuen-Lin; Lin, Tsai-Wei

2012-10-20

We present a new method based on fast Fourier transform (FFT) for evaluating the thermal expansion coefficient and thermomechanical properties of thin films. The silicon nitride thin films deposited on Corning glass and Si wafers were prepared by plasma-enhanced chemical vapor deposition in this study. The anisotropic residual stress and thermomechanical properties of silicon nitride thin films were studied. Residual stresses in thin films were measured by a modified Michelson interferometer associated with the FFT method under different heating temperatures. We found that the average residual-stress value increases when the temperature increases from room temperature to 100°C. Increased substrate temperature causes the residual stress in SiN(x) film deposited on Si wafers to be more compressive, but the residual stress in SiN(x) film on Corning glass becomes more tensile. The residual-stress versus substrate-temperature relation is a linear correlation after heating. A double substrate technique is used to determine the thermal expansion coefficients of the thin films. The experimental results show that the thermal expansion coefficient of the silicon nitride thin films is 3.27×10(-6)°C(-1). The biaxial modulus is 1125 GPa for SiN(x) film.

A thin gold coated hydrogen heat pipe-cryogenic target for external experiments at COSY

Science.gov (United States)

Abdel-Bary, M.; Abdel-Samad, S.; Elawadi, G. A.; Kilian, K.; Ritman, J.

2009-05-01

A gravity assisted Gold coated heat pipe (GCHP) with 5-mm diameter has been developed and tested to cool a liquid hydrogen target for external beam experiments at COSY. The need for a narrow target diameter leads us to study the effect of reducing the heat pipe diameter to 5 mm instead of 7 mm, to study the effect of coating the external surface of the heat pipe by a shiny gold layer (to decrease the radiation heat load), and to study the effect of using the heat pipe without using 20 layers of' super-insulation around it (aluminized Mylar foil) to keep the target diameter as small as possible. The developed gold coated heat pipe was tested with 20 layers of super-insulation (WI) and without super-insulation (WOI). The operating characteristics for both conditions were compared to show the advantages and disadvantages.

Study on residual stress across the pipes' thickness using outer surface rapid heating. Development of pipe outer surface irradiated laser stress improvement process (L-SIP)

International Nuclear Information System (INIS)

Ohta, Takahiro; Terasaki, Toshio

2009-01-01

The new process called L-SIP (outer surface irradiated Laser Stress Improvement Process) is developed to improve the tensile residual stress of the inner surface near the butt welded joints of pipes in the compression stress. The temperature gradient occurs in the thickness of pipes in heating the outer surface rapidly by laser beam. By the thermal expansion difference between the inner surface and the outer surface, the compression plastic strain generates near the outer surface and the tensile plastic strain generates near the inner surface of pipes. The compression stress occurs near the inner surface of pipes by the plastic deformation. In this paper, the theoretical equation which calculates residual stress distribution from the inherent strain distribution in the thickness of pipes is derived. And, the relation between the distribution of temperature and the residual stress in the thickness is examined for various pipes size. (1) By rapidly heating from the outer surface, the residual stress near the inner surface of the pipe is improved to the compression stress. (2) Pipes size hardly affects the distribution of the residual stress in the stainless steel pipes for piping (JISG3459). (3) The temperature rising area from the outside is smaller, the area of the compression residual stress near the inner surface becomes wider. (author)

[Clothing and heat disorder].

Science.gov (United States)

Satsumoto, Yayoi

2012-06-01

The influence of the clothing material properties(like water absorbency and rapid dryness, water vapor absorption, water vapor permeability and air permeability) and the design factor of the clothing(like opening condition and fitting of clothing), which contributed to prevent heat disorder, was outlined. WBGT(wet-bulb globe temperature) is used to show a guideline for environmental limitation of activities to prevent heat disorder. As the safety function is more important than thermal comfort for some sportswear and protective clothing with high cover area, clothing itself increases the risk of heat disorder. WBGT is corrected by CAF (clothing adjustment factor) in wearing such kind of protective clothing.

Thick or Thin Ice Shell on Europa?

Science.gov (United States)

2007-01-01

Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

Methodical Specifics of Thermal Experiments with Thin Carbon Reinforced Plates

Directory of Open Access Journals (Sweden)

O. V. Denisov

2015-01-01

Full Text Available Polymer composite materials (CM are widely used in creation of large space constructions, especially reflectors of space antennas. Composite materials should provide high level of specific stiffness and strength for space structures. Thermal conductivity in reinforcement plane is a significant factor in case of irregular heating space antennas. Nowadays, data on CM reinforcement plane thermal conductivity are limited and existing methods of its defining are imperfect. Basically, traditional methods allow us to define thermal conductivity in perpendicular direction towards the reinforcement plane on the samples of round or rectangular plate. In addition, the thickness of standard samples is larger than space antenna thickness. Consequently, new methods are required. Method of contact heating, which was developed by BMSTU specialists with long hollow carbon beam, could be a perspective way. This article is devoted to the experimental method of contact heating on the thin carbon plates.Thermal tests were supposed to provide a non-stationary temperature field with a gradient being co-directional with the plane reinforcement in the material sample. Experiments were conducted in vacuum chamber to prevent unstructured convection. Experimental thermo-grams processing were calculated by 1-d thermal model for a thin plate. Influence of uncertainty of experimental parameters, such as (radiation emission coefficients of sample surface, glue, temperature sensors and uncertainty of sensors placement on the result of defined thermal conductivity has been estimated. New data on the thermal conductivity in reinforcement plane were obtained within 295 - 375 K temperature range, which can be used to design and develop reflectors of precision space antennas. In the future it is expedient to conduct tests of thin-wall plates from carbon fiber-reinforced plastic in wide temperature range, especially in the low-range temperatures.

Seebeck coefficient of synthesized Titanium Dioxide thin film on FTO glass substrate

Science.gov (United States)

Usop, R.; Hamed, N. K. A.; Megat Hasnan, M. M. I.; Ikeda, H.; Sabri, M. F. M.; Ahmad, M. K.; Said, S. M.; Salleh, F.

2018-04-01

In order to fabricate a thermoelectric device on glass substrate for harvesting waste heat energy through house appliances, the Seebeck coefficient of translucent TiO2 thin film was investigated. The TiO2 thin film was synthesized by using hydrothermal method with F-SnO2 coated glass as substrate. From scanning electron microscopy analysis, the synthesized TiO2 thin film was found to be in nanometer-scale rod structure with a thickness of 4 µm. The Seebeck coefficient was measured in the temperature range of 300 – 400 K. The Seebeck coefficient is found to be in negative value which shows that synthesized film is an n-type semiconductor material, and is lower than the value of bulk-size material. This reduction in Seebeck coefficient of TiO2 thin film is likely due to the low dimensional effect and the difference of carrier concentration.

Tailoring the light absorption of Ag-PZT thin films by controlling the growth of hexagonal- and cubic-phase Ag nanoparticles

Science.gov (United States)

Hu, Tao; Wang, Zongrong; Ma, Ning; Du, Piyi

2017-12-01

PbZr0.52Ti0.48O3 thin films containing hexagonal and cubic Ag nanoparticles (Ag NPs) of various sizes were prepared using the sol-gel technique. During the aging process, Ag ions were photo-reduced to form hexagonal Ag NPs. These NPs were uniform in size, and their uniformity was maintained in the thin films during the heat treatment process. Both the total volume and average size of the hexagonal Ag NPs increased with an increasing Ag ion concentration from 0.02 to 0.08 mol l-1. Meanwhile, the remaining Ag ions were reduced to form unstable Ag-Pb alloy particles with Pb ions during the early heating stage. During subsequent heat treatment, these alloys decomposed to form cubic Ag NPs in the thin films. The absorption range of the thin films, quantified as the full width at half maximum in the ultraviolet-visible absorption spectrum, expanded from 6.3 × 1013 Hz (390-425 nm) to 8.4 × 1013 Hz (383-429 nm) as the Ag NPs/PZT ratio increased from 0.2 to 0.8. This work provides an effective way to broaden the absorption range and enhance the optical properties of such films.

Tailoring the light absorption of Ag-PZT thin films by controlling the growth of hexagonal- and cubic-phase Ag nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hu, Tao; Wang, Zongrong; Ma, Ning; Du, Piyi [Zhejiang University, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Hangzhou (China)

2017-12-15

PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} thin films containing hexagonal and cubic Ag nanoparticles (Ag NPs) of various sizes were prepared using the sol-gel technique. During the aging process, Ag ions were photo-reduced to form hexagonal Ag NPs. These NPs were uniform in size, and their uniformity was maintained in the thin films during the heat treatment process. Both the total volume and average size of the hexagonal Ag NPs increased with an increasing Ag ion concentration from 0.02 to 0.08 mol l{sup -1}. Meanwhile, the remaining Ag ions were reduced to form unstable Ag-Pb alloy particles with Pb ions during the early heating stage. During subsequent heat treatment, these alloys decomposed to form cubic Ag NPs in the thin films. The absorption range of the thin films, quantified as the full width at half maximum in the ultraviolet-visible absorption spectrum, expanded from 6.3 x 10{sup 13} Hz (390-425 nm) to 8.4 x 10{sup 13} Hz (383-429 nm) as the Ag NPs/PZT ratio increased from 0.2 to 0.8. This work provides an effective way to broaden the absorption range and enhance the optical properties of such films. (orig.)

Measurement of incident molecular temperature in the formation of organic thin films

Science.gov (United States)

Abe, Takahiro; Matsubara, Ryosuke; Hayakawa, Munetaka; Shimoyama, Akifumi; Tanaka, Takaaki; Tsuji, Akira; Takahashi, Yoshikazu; Kubono, Atsushi

2018-03-01

To investigate the effects of incident molecular temperature on organic-thin-film growth by vacuum evaporation, quantitative analysis of molecular temperature is required. In this study, we propose a method of determining molecular temperature based on the heat exchange between a platinum filament and molecular vapor. Molecular temperature is estimated from filament temperature, which remains unchanged even under molecular vapor supply. The results indicate that our method has sufficient sensitivity to evaluate the molecular temperature under the typical growth rate used for fabrication of functional organic thin films.

Low grade heat utilisation for seawater desalination by the HTTF process

Energy Technology Data Exchange (ETDEWEB)

Chandrasekhar, M. [Desalination Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai (India)]. E-mail: mchansh@magnum.barc.ernet.in; Majumdar, M.; Srivastava, V.K.; Tewari, P.K. [Desalination Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai (India)

2006-07-01

To improve heat transfer efficiency, Horizontal Tube Thin Film (HTTF) evaporators are being used in multieffect desalination plants. These plants require less pumping energy than thermal-based desalination plants. To generate the design data, experimental studies were carried out in a single-tube HTTF experimental setup, and heat transfer correlations were developed at BARC. The experimental findings and results are presented and discussed in this paper. (author)

The Characterization of Thin Film Nickel Titanium Shape Memory Alloys

Science.gov (United States)

Harris Odum, Nicole Latrice

Shape memory alloys (SMA) are able to recover their original shape through the appropriate heat or stress exposure after enduring mechanical deformation at a low temperature. Numerous alloy systems have been discovered which produce this unique feature like TiNb, AgCd, NiAl, NiTi, and CuZnAl. Since their discovery, bulk scale SMAs have undergone extensive material property investigations and are employed in real world applications. However, its thin film counterparts have been modestly investigated and applied. Researchers have introduced numerous theoretical microelectromechanical system (MEMS) devices; yet, the research community's overall unfamiliarity with the thin film properties has delayed growth in this area. In addition, it has been difficult to outline efficient thin film processing techniques. In this dissertation, NiTi thin film processing and characterization techniques will be outlined and discussed. NiTi thin films---1 mum thick---were produced using sputter deposition techniques. Substrate bound thin films were deposited to analysis the surface using Scanning Electron Microscopy; the film composition was obtained using Energy Dispersive Spectroscopy; the phases were identified using X-ray diffraction; and the transformation temperatures acquired using resistivity testing. Microfabrication processing and sputter deposition were employed to develop tensile membranes for membrane deflection experimentation to gain insight on the mechanical properties of the thin films. The incorporation of these findings will aid in the movement of SMA microactuation devices from theory to fruition and greatly benefit industries such as medicinal and aeronautical.

Effects of the substrate temperature on the properties of CuIn5S8 thin films

International Nuclear Information System (INIS)

Gannouni, M.; Kanzari, M.

2011-01-01

Structural, optical and electrical properties of CuIn 5 S 8 thin films grown by thermal evaporation have been studied relating the effects of substrate heating conditions of these properties. The CuIn 5 S 8 thin films were carried out at substrate temperatures in the temperature range 100-300 deg. C. The effects of heated substrate on their physico-chemical properties were investigated using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), optical transmission and hot probe method. X-ray diffraction revealed that the films are strong preferred orientation along the (3 1 1) plane upon substrate temperature 200 deg. C and amorphous for the substrate temperatures below 200 deg. C. No secondary phases are observed for all the films. The composition is greatly affected by heated substrate. From the optical transmission and reflection, an important absorption coefficient exceeds 10 5 cm -1 at 800 nm was found. As increasing the substrate temperature, the optical energy band gap decreases from 1.70 eV for the unheated films to 1.25 eV for the deposited films at 300 deg. C. It was found that CuIn 5 S 8 thin film is an n-type semiconductor at 250 deg. C.

Using Gravity Inversion to Estimate Antarctic Geothermal Heat Flux

Science.gov (United States)

Vaughan, Alan P. M.; Kusznir, Nick J.; Ferraccioli, Fausto; Leat, Phil T.; Jordan, Tom A. R. M.; Purucker, Michael E.; (Sasha) Golynsky, A. V.; Rogozhina, Irina

2014-05-01

New modelling studies for Greenland have recently underlined the importance of GHF for long-term ice sheet behaviour (Petrunin et al. 2013). Revised determinations of top basement heat-flow for Antarctica and adjacent rifted continental margins using gravity inversion mapping of crustal thickness and continental lithosphere thinning (Chappell & Kusznir 2008), using BedMap2 data have provided improved estimates of geothermal heat flux (GHF) in Antarctica where it is very poorly known. Continental lithosphere thinning and post-breakup residual thicknesses of continental crust determined from gravity inversion have been used to predict the preservation of continental crustal radiogenic heat productivity and the transient lithosphere heat-flow contribution within thermally equilibrating rifted continental and oceanic lithosphere. The sensitivity of present-day Antarctic top basement heat-flow to initial continental radiogenic heat productivity, continental rift and margin breakup age has been examined. Recognition of the East Antarctic Rift System (EARS), a major Permian to Cretaceous age rift system that appears to extend from the continental margin at the Lambert Rift to the South Pole region, a distance of 2500 km (Ferraccioli et al. 2011) and is comparable in scale to the well-studied East African rift system, highlights that crustal variability in interior Antarctica is much greater than previously assumed. GHF is also important to understand proposed ice accretion at the base of the EAIS in the GSM and its links to sub-ice hydrology (Bell et al. 2011). References Bell, R.E., Ferraccioli, F., Creyts, T.T., Braaten, D., Corr, H., Das, I., Damaske, D., Frearson, N., Jordan, T., Rose, K., Studinger, M. & Wolovick, M. 2011. Widespread persistent thickening of the East Antarctic Ice Sheet by freezing from the base. Science, 331 (6024), 1592-1595. Chappell, A.R. & Kusznir, N.J. 2008. Three-dimensional gravity inversion for Moho depth at rifted continental margins

Process for forming epitaxial perovskite thin film layers using halide precursors

Science.gov (United States)

Clem, Paul G.; Rodriguez, Mark A.; Voigt, James A.; Ashley, Carol S.

2001-01-01

A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

ZnO-Based Transparent Conductive Thin Films: Doping, Performance, and Processing

International Nuclear Information System (INIS)

Liu, Y.; Li, Y.; Zeng, H.

2013-01-01

ZnO-based transparent conductive thin films have attracted much attention as a promising substitute material to the currently used indium-tin-oxide thin films in transparent electrode applications. However, the detailed function of the dopants, acting on the electrical and optical properties of ZnO-based transparent conductive thin films, is not clear yet, which has limited the development and practical applications of ZnO transparent conductive thin films. Growth conditions such as substrate type, growth temperature, and ambient atmosphere all play important roles in structural, electrical, and optical properties of films. This paper takes a panoramic view on properties of ZnO thin films and reviews the very recent works on new, efficient, low-temperature, and high-speed deposition technologies. In addition, we highlighted the methods of producing ZnO-based transparent conductive film on flexible substrate, one of the most promising and rapidly emerging research areas. As optimum-processing-parameter conditions are being obtained and their influencing mechanism is becoming clear, we can see that there will be a promising future for ZnO-based transparent conductive films.

Fabrication of a Cu(InGaSe2 Thin Film Photovoltaic Absorber by Rapid Thermal Annealing of CuGa/In Precursors Coated with a Se Layer

Directory of Open Access Journals (Sweden)

Chun-Yao Hsu

2013-01-01

Full Text Available Cu(InGaSe2 (CIGS thin film absorbers are prepared using sputtering and selenization processes. The CuGa/In precursors are selenized during rapid thermal annealing (RTA, by the deposition of a Se layer on them. This work investigates the effect of the Cu content in precursors on the structural and electrical properties of the absorber. Using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurement, it is found that the CIGS thin films produced exhibit facetted grains and a single chalcopyrite phase with a preferred orientation along the (1 1 2 plane. A Cu-poor precursor with a Cu/( ratio of 0.75 demonstrates a higher resistance, due to an increase in the grain boundary scattering and a reduced carrier lifetime. A Cu-rich precursor with a Cu/( ratio of 1.15 exhibits an inappropriate second phase ( in the absorber. However, the precursor with a Cu/( ratio of 0.95 exhibits larger grains and lower resistance, which is suitable for its application to solar cells. The deposition of this precursor on Mo-coated soda lime glass substrate and further RTA causes the formation of a MoSe2 layer at the interface of the Mo and CIGS.

A chemical route to room-temperature synthesis of nanocrystalline TiO2 thin films

International Nuclear Information System (INIS)

Pathan, Habib M.; Kim, Woo Young; Jung, Kwang-Deog; Joo, Oh-Shim

2005-01-01

A lot of methods are developed for the deposition of TiO 2 thin films; however, in each of these methods as-deposited films are amorphous and need further heat treatment at high temperature. In the present article, a chemical bath deposition (CBD) method was used for the preparation of TiO 2 thin films. We investigated nanocrystalline TiO 2 thin films using CBD at room temperature onto glass and ITO coated glass substrate. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The chemically synthesized films were nanocrystalline and composed of crystal grains of 2-3 nm

Turbulent energy losses during orchard heating

Energy Technology Data Exchange (ETDEWEB)

Bland, W.L.

1979-01-01

Two rapid-response drag anemometers and low time constant thermocouples, all at 4 m above a heated orchard floor, sampled wind component in the vertical direction and temperature at 30 Hz. The turbulent heat flux calculated revealed not more than 10% of the heat lost from the orchard was via turbulent transort. The observations failed to support previous estimates that at least a third of the energy applied was lost through turbulent transport. Underestimation of heat loss due to mean flow and a newly revealed flux due to spatial variations in the mean flow may explain the unaccounted for loss.

Analysis of flow distribution instability in parallel thin rectangular multi-channel system

Energy Technology Data Exchange (ETDEWEB)

Xia, G.L. [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an City 710049 (China); Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin City 150001 (China); Su, G.H., E-mail: ghsu@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an City 710049 (China); Peng, M.J. [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin City 150001 (China)

2016-08-15

Highlights: • Flow distribution instability in parallel thin rectangular multi-channel system is studied using RELAP5 codes. • Flow excursion may bring parallel heating channel into the density wave oscillations region. • Flow distribution instability is more likely to happen at low power/flow ratio conditions. • The increase of channel number will not affect the flow distribution instability boundary. • Asymmetry inlet throttling and heating will make system more unstable. - Abstract: The flow distribution instability in parallel thin rectangular multi-channel system has been researched in the present study. The research model of parallel channel system is established by using RELAP5/MOD3.4 codes. The transient process of flow distribution instability is studied at imposed inlet mass flow rate and imposed pressure drop conditions. The influence of heating power, mass flow rate, system pressure and channel number on flow distribution instability are analyzed. Furthermore, the flow distribution instability of parallel two-channel system under asymmetric inlet throttling and heating power is studied. The results show that, if multi-channel system operates at the negative slope region of channel ΔP–G curve, small disturbance in pressure drop will lead to flow redistribution between parallel channels. Flow excursion may bring the operating point of heating channel into the density-wave oscillations region, this will result in out-phase or in-phase flow oscillations. Flow distribution instability is more likely to happen at low power/flow ratio conditions, the stability of parallel channel system increases with system pressure, the channel number has a little effect on system stability, but the asymmetry inlet throttling or heating power will make the system more unstable.

Exertional heat illness: emerging concepts and advances in prehospital care.

Science.gov (United States)

Pryor, Riana R; Roth, Ronald N; Suyama, Joe; Hostler, David

2015-06-01

Exertional heat illness is a classification of disease with clinical presentations that are not always diagnosed easily. Exertional heat stroke is a significant cause of death in competitive sports, and the increasing popularity of marathons races and ultra-endurance competitions will make treating many heat illnesses more common for Emergency Medical Services (EMS) providers. Although evidence is available primarily from case series and healthy volunteer studies, the consensus for treating exertional heat illness, coupled with altered mental status, is whole body rapid cooling. Cold or ice water immersion remains the most effective treatment to achieve this goal. External thermometry is unreliable in the context of heat stress and direct internal temperature measurement by rectal or esophageal probes must be used when diagnosing heat illness and during cooling. With rapid recognition and implementation of effective cooling, most patients suffering from exertional heat stroke will recover quickly and can be discharged home with instructions to rest and to avoid heat stress and exercise for a minimum of 48 hours; although, further research pertaining to return to activity is warranted.

Correlations of Nucleate Boiling Heat Transfer and Critical Heat Flux for External Reactor Vessel Cooling

International Nuclear Information System (INIS)

J. Yang; F. B. Cheung; J. L. Rempe; K. Y. Suh; S. B. Kim

2005-01-01

Four types of steady-state boiling experiments were conducted to investigate the efficacy of two distinctly different heat transfer enhancement methods for external reactor vessel cooling under severe accident conditions. One method involved the use of a thin vessel coating and the other involved the use of an enhanced insulation structure. By comparing the results obtained in the four types of experiments, the separate and integral effect of vessel coating and insulation structure were determined. Correlation equations were obtained for the nucleate boiling heat transfer and the critical heat flux. It was found that both enhancement methods were quite effective. Depending on the angular location, the local critical heat flux could be enhanced by 1.4 to 2.5 times using vessel coating alone whereas it could be enhanced by 1.8 to 3.0 times using an enhanced insulation structure alone. When both vessel coating and insulation structure were used simultaneously, the integral effect on the enhancement was found much less than the product of the two separate effects, indicating possible competing mechanisms (i.e., interference) between the two enhancement methods

Effects of X irradiation and high field electron injection of the electrical properties of rapid thermal oxides

International Nuclear Information System (INIS)

Schubert, W.K.; Seager, C.H.

1988-01-01

Rapid thermal oxidation (RTO) is a promising tool for fabricating the thin gate oxides (5 to 15 nm) that will be needed in future submicron integrated circuits, because of its inherently superior time-temperature control when compared to conventional oxidation methods. It is important to demonstrate that RTO can be used without adversely affecting the radiation hardness or high field properties of the oxide. Beyond this demonstration, rapid thermal processing makes it possible to determine more precisely how the kinetics of oxidation and post oxidation annealing affect the device properties. Information of this type should prove useful in modeling relevant defect formation mechanisms. The present paper is part of a systematic study of the effect of rapid thermal processing on the radiation and high field response of thin oxides

Investigation of phase transformation for ferrite–austenite structure in stainless steel thin films

Energy Technology Data Exchange (ETDEWEB)

Merakeb, Noureddine [Laboratory of Physical Metallurgy and Property of Materials (LM2PM), Metallurgy and Materials Engineering Department, Badji Mokhtar University, P.O. Box 12, Annaba 23000 (Algeria); Messai, Amel [Laboratoire d' Ingénierie et Sciences des Matériaux Avancés (ISMA), Institut des Sciences et Technologie, Abbès Laghrour University, Khenchela 40000 (Algeria); Ayesh, Ahmad I., E-mail: ayesh@qu.edu.qa [Department of Mathematics, Statistics and Physics, Qatar University, Doha (Qatar)

2016-05-01

In this work we report on phase transformation of 304 stainless steel thin films due to heat treatment. Ex-situ annealing was applied for evaporated 304 stainless steel thin films inside an ultra-high vacuum chamber with a pressure of 3 × 10{sup −7} Pa at temperatures of 500 °C and 600 °C. The structure of thin films was studied by X-ray diffraction (XRD) and conversion electron Mössbauer spectroscopy (CEMS) techniques. The results revealed a transformation from α-phase that exhibits a body-centered cubic structure (BCC) to γ-phase that exhibits a face-centered cubic (FCC) due to annealing. In addition, the percentage of γ-phase structure increased with the increase of annealing temperature. Annealing thin films increased the crystal size of both phases (α and γ), however, the increase was nonlinear. The results also showed that phase transformation was produced by recrystallization of α and γ crystals with a temporal evolution at each annealing temperature. The texture degree of thin films was investigated by XRD rocking curve method, while residual stress was evaluated using curvature method. - Highlights: • Stainless steel thin films were fabricated by thermal evaporation on quartz. • Alpha to gamma phase transformation of thin films was investigated. • Annealing of thin films reduces disruption in crystal lattice. • The stress of as-grown thin films was independent on the thin film thickness. • The stress of the thin films was reduced due to annealing.

Development of laser cladding technology for maintenance of pipe wall thinning

International Nuclear Information System (INIS)

Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi

2011-01-01

We are developing the laser welding and cladding device for the maintenance of heat exchanger pipes. In the case of flow accelerated corrosion where pipe wall thinning occurred after a long time operation, laser cladding is mostly expected. A laser processing head was proposed in order to access the pipe wall. A composite-type optical fiber scope was used for real time observation and laser processing. An air-cooled compact fiber laser was used for spot heating. We present the concept of the laser cladding device which have the following features: 1) Wire feeding modules, 2) Module capable of laser irradiation in the vertical heat exchanger pipe, 3) Assist gas injection module. (author)

Estimating Antarctic Geothermal Heat Flux using Gravity Inversion

Science.gov (United States)

Vaughan, Alan P. M.; Kusznir, Nick J.; Ferraccioli, Fausto; Leat, Phil T.; Jordan, Tom A. R. M.; Purucker, Michael E.; Golynsky, A. V.; Sasha Rogozhina, Irina

2013-04-01

Geothermal heat flux (GHF) in Antarctica is very poorly known. We have determined (Vaughan et al. 2012) top basement heat-flow for Antarctica and adjacent rifted continental margins using gravity inversion mapping of crustal thickness and continental lithosphere thinning (Chappell & Kusznir 2008). Continental lithosphere thinning and post-breakup residual thicknesses of continental crust determined from gravity inversion have been used to predict the preservation of continental crustal radiogenic heat productivity and the transient lithosphere heat-flow contribution within thermally equilibrating rifted continental and oceanic lithosphere. The sensitivity of present-day Antarctic top basement heat-flow to initial continental radiogenic heat productivity, continental rift and margin breakup age has been examined. Knowing GHF distribution for East Antarctica and the Gamburtsev Subglacial Mountains (GSM) region in particular is critical because: 1) The GSM likely acted as key nucleation point for the East Antarctic Ice Sheet (EAIS); 2) the region may contain the oldest ice of the EAIS - a prime target for future ice core drilling; 3) GHF is important to understand proposed ice accretion at the base of the EAIS in the GSM and its links to sub-ice hydrology (Bell et al. 2011). An integrated multi-dataset-based GHF model for East Antarctica is planned that will resolve the wide range of estimates previously published using single datasets. The new map and existing GHF distribution estimates available for Antarctica will be evaluated using direct ice temperature measurements obtained from deep ice cores, estimates of GHF derived from subglacial lakes, and a thermodynamic ice-sheet model of the Antarctic Ice Sheet driven by past climate reconstructions and each of analysed heat flow maps, as has recently been done for the Greenland region (Rogozhina et al. 2012). References Bell, R.E., Ferraccioli, F., Creyts, T.T., Braaten, D., Corr, H., Das, I., Damaske, D., Frearson, N

Heating effects in a liquid metal ion source

International Nuclear Information System (INIS)

Mair, G.L.R.; Aitken, K.L.

1984-01-01

A reassessment is made of the heating occurring at the anode of a liquid metal ion source, in the light of new microscopic observations. The apex region of the cones is in the form of a cusp, or jet, even at very low currents. The calculation for ohmic heating is conclusive for low currents; no heating occurs at the anode; for high currents (approx. 50-100 μA), substantial heating is conceivable, if a long, very thin, cylindrical jet exists at the apex of the anode. The answer to the problem of external heating, in the form of electrons bombarding the anode, is not quite conclusive; this is because of the impossibility of correctly assessing the electron flux entering the anode. However, it would appear to be a definite conclusion that for reasons of self-consistency field-ionisation of thermally released atoms cannot be a significant ion emission mechanism. (author)

Origin of room temperature ferromagnetic moment in Rh-rich [Rh/Fe] multilayer thin films

International Nuclear Information System (INIS)

Kande, Dhishan; Laughlin, David; Zhu Jiangang

2010-01-01

B2 ordered FeRh thin films switch from antiferromagnetic (AFM) to ferromagnetic (FM) state on heating above 350 K and switch back on cooling, with a hysteresis. This property makes FeRh a very attractive choice as a write-assist layer material for low temperature heat assisted magnetic recording (HAMR) media. Studies have shown that as we decrease the thickness of the FeRh films, the B2 phase is no longer AFM even below 350 K and there is a thickness dependant FM stabilization of the B2 phase. It was also proved that slightly Rh-richer compositions (>50 at. % Rh) were more preferable to stabilize the AFM phase. The current study focuses on growing highly ordered FeRh films by alternate layer rf sputtering of thin layers of iron and rhodium onto a heated substrate. It has been shown that films with rhodium content beyond 55 at. % contain a disordered bcc FM phase which gives rise to residual moment at room temperature even for thicker films.

In-situ observations of stress-induced thin film failures

Energy Technology Data Exchange (ETDEWEB)

Zhao, Z.B., E-mail: zzhao@firstsolar.co [Delphi Research Labs, 51786 Shelby Parkway, Shelby Twp., MI 48315 (United States); Hershberger, J. [Laird Technologies, 4707 Detroit Avenue, Cleveland, Ohio, 44102 (United States); Bilello, J.C. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109-2136 (United States)

2010-02-01

In this work, the failure modes of thin films under thermo-mechanical treatments were observed via in-situ white beam X-ray topography. The in-situ experiments were carried out using an experimental setup on Beamline 2-2 at the Stanford Synchrotron Radiation Laboratory. Magnetron sputtered polycrystalline thin films of Ta and CrN on Si substrates were selected for the present study due to their disparate states of intrinsic residual stresses: the Ta film was anisotropically compressive and the CrN film was isotropically tensile. Under a similar heating-cooling cycle in air, the two types of films exhibited distinct failure modes, which were observed in-situ and in a quasi-real-time fashion. The failures of the samples have been interpreted based on their distinctive growth stress states, superimposed on the additional stress development associated with different forms of thermal instabilities upon heating. These included the formation of oxide for the Ta/Si sample, which led to an increase in compressive stress, and a phase change for the CrN/Si sample, which caused the isotropic stress in the film to become increasingly tensile.

In-situ observations of stress-induced thin film failures

International Nuclear Information System (INIS)

Zhao, Z.B.; Hershberger, J.; Bilello, J.C.

2010-01-01

In this work, the failure modes of thin films under thermo-mechanical treatments were observed via in-situ white beam X-ray topography. The in-situ experiments were carried out using an experimental setup on Beamline 2-2 at the Stanford Synchrotron Radiation Laboratory. Magnetron sputtered polycrystalline thin films of Ta and CrN on Si substrates were selected for the present study due to their disparate states of intrinsic residual stresses: the Ta film was anisotropically compressive and the CrN film was isotropically tensile. Under a similar heating-cooling cycle in air, the two types of films exhibited distinct failure modes, which were observed in-situ and in a quasi-real-time fashion. The failures of the samples have been interpreted based on their distinctive growth stress states, superimposed on the additional stress development associated with different forms of thermal instabilities upon heating. These included the formation of oxide for the Ta/Si sample, which led to an increase in compressive stress, and a phase change for the CrN/Si sample, which caused the isotropic stress in the film to become increasingly tensile.

Possible artefacts in thin layer chromatography of tritium-labelled hydrocortisone

International Nuclear Information System (INIS)

Sofronie, E.

1982-12-01

Artefacts appearing in thin layer chromatography of tritium labelled hydrocortisone are reported. Evidences are presented that these artefacts cause misleading results concerning radiocheemical purity determiniation. Finally, it is reported a rapid and efficient chromatographic technique allowing the elimination of these artefacts and obtaining of an accurate value for radiochemical purity. (author)

Note: Anodic bonding with cooling of heat-sensitive areas

DEFF Research Database (Denmark)

Vesborg, Peter Christian Kjærgaard; Olsen, Jakob Lind; Henriksen, Toke Riishøj

2010-01-01

Anodic bonding of silicon to glass always involves heating the glass and device to high temperatures so that cations become mobile in the electric field. We present a simple way of bonding thin silicon samples to borosilicate glass by means of heating from the glass side while locally cooling hea......-sensitive areas from the silicon side. Despite the high thermal conductivity of silicon, this method allows a strong anodic bond to form just millimeters away from areas essentially at room temperature....