Study of polytropic exponent based on high pressure switching expansion reduction

NASA Astrophysics Data System (ADS)

Wang, Xuanyin; Luo, Yuxi; Xu, Zhipeng

2011-10-01

Switching expansion reduction (SER) uses a switch valve to substitute the throttle valve to reduce pressure for high pressure pneumatics. The experiments indicate that the simulation model well predicts the actual characteristics. The heat transfers and polytropic exponents of the air in expansion tank and supply tanks of SER have been studied on the basis of the experiments and the simulation model. Through the mathematical reasoning in this paper, the polytropic exponent can be calculated by the air mass, heat, and work exchanges of the pneumatic container. For the air in a constant volume tank, when the heat-absorption is large enough to raise air temperature in discharging process, the polytropic exponent is less than 1; when the air is experiencing a discharging and heat-releasing process, the polytropic exponent exceeds the specific heat ratio (the value of 1.4).

Experiments Demonstrate Geothermal Heating Process

ERIC Educational Resources Information Center

Roman, Harry T.

2012-01-01

When engineers design heat-pump-based geothermal heating systems for homes and other buildings, they can use coil loops buried around the perimeter of the structure to gather low-grade heat from the earth. As an alternative approach, they can drill well casings and store the summer's heat deep in the earth, then bring it back in the winter to warm…

Boiling Experiment Facility for Heat Transfer Studies in Microgravity

NASA Technical Reports Server (NTRS)

Delombard, Richard; McQuillen, John; Chao, David

2008-01-01

Pool boiling in microgravity is an area of both scientific and practical interest. By conducting tests in microgravity, it is possible to assess the effect of buoyancy on the overall boiling process and assess the relative magnitude of effects with regards to other "forces" and phenomena such as Marangoni forces, liquid momentum forces, and microlayer evaporation. The Boiling eXperiment Facility is now being built for the Microgravity Science Glovebox that will use normal perfluorohexane as a test fluid to extend the range of test conditions to include longer test durations and less liquid subcooling. Two experiments, the Microheater Array Boiling Experiment and the Nucleate Pool Boiling eXperiment will use the Boiling eXperiment Facility. The objectives of these studies are to determine the differences in local boiling heat transfer mechanisms in microgravity and normal gravity from nucleate boiling, through critical heat flux and into the transition boiling regime and to examine the bubble nucleation, growth, departure and coalescence processes. Custom-designed heaters will be utilized to achieve these objectives.

Solution Calorimetry Experiments for Physical Chemistry.

ERIC Educational Resources Information Center

Raizen, Deborah A.; And Others

1988-01-01

Presents two experiments: the first one measures the heat of an exothermic reaction by the reduction of permanganate by the ferris ion; the second one measures the heat of an endothermic process, the mixing of ethanol and cyclohexane. Lists tables to aid in the use of the solution calorimeter. (MVL)

Influence of the heat transfer on the thermoelastic response of metals on heating by the laser pulse

NASA Astrophysics Data System (ADS)

Sudenkov, Y. V.; Zimin, B. A.; Sventitskaya, V. E.

2018-05-01

The paper presents an analysis of the effect of the heat transfer process in metals on the parameters of thermal stresses under pulsed laser action. The dynamic problem of thermoelasticity is considered as a two-stage process. The first stage is determined by the time of action of the radiation pulse. The second stage is caused by the dynamics of the heat transfer process after the end of the laser pulse. For showing the continuity of thermoelastic and thermoelectric processes, the analysis of the electronic mechanism for the propagation of heat in metals and the results of experimental studies of these processes are presented. The results of the experiments demonstrate the high sensitivity of the parameters of thermoelastic and thermoelectric pulses to the microstructure of metals.

Influence of heating experiments on parameters of Schumann resonances

NASA Astrophysics Data System (ADS)

Agranat, Irina; Sivokon, Vladimir

2017-10-01

Recently the significant increase in intensity of researches in the field of the fissile impact on geophysical processes in various environments is noted. Special attention is paid to a research of impact on an ionosphere of a potent short-wave radio emission of heating stands. Today experiments on change of an ionosphere are made generally at stands HAARP, EISCAT in Tromse (Norway). Within the Russian campaign (Tomsk) EISCAT/heating (AARI_HFOX) made from October 19 to October 30, 2016 experiments on impact on an ionosphere F-layer by the radiation potent HF. For assessment of impact of these experiments on geophysical processes mathematical methods carried out the analysis of change of the parameters of the Schumann resonances received on the basis of data from the station of constant observation of the Schumann resonances in the city of Tomsk, the Tomsk State University (Russia).

Heat transfer, diffusion, and evaporation

NASA Technical Reports Server (NTRS)

Nusselt, Wilhelm

1954-01-01

Although it has long been known that the differential equations of the heat-transfer and diffusion processes are identical, application to technical problems has only recently been made. In 1916 it was shown that the speed of oxidation of the carbon in iron ore depends upon the speed with which the oxygen of the combustion air diffuses through the core of gas surrounding the carbon surface. The identity previously referred to was then used to calculate the amount of oxygen diffusing to the carbon surface on the basis of the heat transfer between the gas stream and the carbon surface. Then in 1921, H. Thoma reversed that procedure; he used diffusion experiments to determine heat-transfer coefficients. Recently Lohrisch has extended this work by experiment. A technically very important application of the identity of heat transfer and diffusion is that of the cooling tower, since in this case both processes occur simultaneously.

Restoration of the Apollo 15 Heat Flow Experiment Data from 1975 to 1977

NASA Technical Reports Server (NTRS)

Nagihara, S.; Nakamura, Y.; Taylor, P. T.; Williams, D. R.; Kiefer, W. S.

2017-01-01

The Apollo 15 Heat Flow Experiment (HFE) was conducted from July 1971 through January 1977. Two heat flow probes were deployed roughly 8.5 meters apart. Probe 1 and Probe 2 penetrated to 1.4-meters and 1-meter depths into the lunar regolith, respectively. Temperatures at different depths and the surface were logged with 7.25-minute intervals and transmitted to Earth. At the conclusion of the experiment, only data obtained from July 1971 through December 1974 were processed and archived at the National Space Science Data Center (NSSDC) by the principal investigator of the experiment, Marcus Langseth of Columbia University. Langseth died in 1997. It is not known what happened to the HFE data tapes he used. Current researchers have strong interests in re-examining the HFE data for the full duration of the experiment. We have recovered and processed large portions of the Apollo 15 HFE data from 1975 through 1977 by assembling data and metadata from various sources.

Practical and efficient magnetic heat pump

NASA Technical Reports Server (NTRS)

Brown, G. V.

1978-01-01

Method for pumping heat magnetically at room temperature is more economical than existing refrigeration systems. Method uses natural magneto-thermal effect of gadolinium metal to establish temperature gradient across length of tube. Regenerative cyclic process in which gadolinium sample is magnetized and gives off heat at one end of tube, and then is demagnetized at other end to absorb heat has established temperature gradients of 144 degrees F in experiments near room temperature. Other materials with large magnetothermal effects can be used below room temperature. Possible commercial applications include freeze-drying and food processing, cold storage, and heating and cooling of buildings, plants, and ships.

Tank Pressure Control Experiment: Thermal Phenomena in Microgravity. Video 3 of 4

NASA Technical Reports Server (NTRS)

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83 percent by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/m(exp 2)). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 deg C, respectively. The boiling process during the entire heating period, as well a jet-induced mixing process for the first 2 min. of the mixing period, was also recorded on video. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number. This is video 3 of 4.

Tank Pressure Control Experiment: Thermal Phenomena in Microgravity. Video 4 of 4

NASA Technical Reports Server (NTRS)

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83 percent by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/m(exp 2)). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 deg C, respectively. The boiling process during the entire heating period, as well a jet-induced mixing process for the first 2 min. of the mixing period, was also recorded on video. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number. This is video 4 of 4.

Tank Pressure Control Experiment: Thermal Phenomena in Microgravity. Video 1 of 4

NASA Technical Reports Server (NTRS)

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83 percent by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/m(exp 2)). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 deg C, respectively. The boiling process during the entire heating period, as well a jet-induced mixing process for the first 2 min. of the mixing period, was also recorded on video. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number. This is video 1 of 4.

Tank Pressure Control Experiment: Thermal Phenomena in Microgravity. Video 2 of 4

NASA Technical Reports Server (NTRS)

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83 percent by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/m(exp 2)). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 deg C, respectively. The boiling process during the entire heating period, as well a jet-induced mixing process for the first 2 min. of the mixing period, was also recorded on video. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number. This is video 2 of 4.

Tank Pressure Control Experiment: Thermal Phenomena in Microgravity

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Lin, Chin S.; Knoll, Richard H.; Bentz, Michael D.

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83% by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/sq m). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 C, respectively. The boiling process during the entire heating period, as well as the jet-induced mixing process for the first 2 min of the mixing period, was also recorded on video. The unique features of the experimental results are the sustainability of high liquid superheats for long periods and the occurrence of explosive boiling at low heat fluxes (0.86 to 1.1 kW/sq m). For a heat flux of 0.97 kW/sq m, a wall superheat of 17.9 C was attained in 10 min of heating. This superheat was followed by an explosive boiling accompanied by a pressure spike of about 38% of the tank pressure at the inception of boiling. However, at this heat flux the vapor blanketing the heating surface could not be sustained. Steady nucleate boiling continued after the explosive boiling. The jet-induced fluid mixing results were obtained for jet Reynolds numbers of 1900 to 8000 and Weber numbers of 0.2 to 6.5. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number.

Utilization of Induction Bonding for Automated Fabrication of TIGR

NASA Technical Reports Server (NTRS)

Hinkley, Jeffrey A.; Johnston, Norman J.; Hulcher, A. Bruce; Marchello, Joseph M.; Messier, Bernadette C.

1999-01-01

A laboratory study of magnetic induction heat bonding of titanium foil and graphite fiber reinforced polymer prepreg tape, TiGr, demonstrated that the process is a viable candidate for low cost fabrication of aircraft structure made of this new material form. Data were obtained on weld bonding of PIXA and PETI-5 prepreg to titanium. Both the foil and honeycomb forms of titanium were investigated. The process relies on magnetic susceptor heating of titanium, not on high frequency heating of graphite fiber. The experiments showed that with a toroid magnet configuration, good weld bonds might be obtained with heating times of a few seconds. These results suggest the potential is good for the induction heating process to achieve acceptable commercial production rates.

Basic Comfort Heating Principles.

ERIC Educational Resources Information Center

Dempster, Chalmer T.

The material in this beginning book for vocational students presents fundamental principles needed to understand the heating aspect of the sheet metal trade and supplies practical experience to the student so that he may become familiar with the process of determining heat loss for average structures. Six areas covered are: (1) Background…

Forging of Advanced Disk Alloy LSHR

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.; Gayda, John; Falsey, John

2005-01-01

The powder metallurgy disk alloy LSHR was designed with a relatively low gamma precipitate solvus temperature and high refractory element content to allow versatile heat treatment processing combined with high tensile, creep and fatigue properties. Grain size can be chiefly controlled through proper selection of solution heat treatment temperatures relative to the gamma precipitate solvus temperature. However, forging process conditions can also significantly influence solution heat treatment-grain size response. Therefore, it is necessary to understand the relationships between forging process conditions and the eventual grain size of solution heat treated material. A series of forging experiments were performed with subsequent subsolvus and supersolvus heat treatments, in search of suitable forging conditions for producing uniform fine grain and coarse grain microstructures. Subsolvus, supersolvus, and combined subsolvus plus supersolvus heat treatments were then applied. Forging and subsequent heat treatment conditions were identified allowing uniform fine and coarse grain microstructures.

Modeling conductive heat transfer during high-pressure thawing processes: determination of latent heat as a function of pressure.

PubMed

Denys, S; Van Loey, A M; Hendrickx, M E

2000-01-01

A numerical heat transfer model for predicting product temperature profiles during high-pressure thawing processes was recently proposed by the authors. In the present work, the predictive capacity of the model was considerably improved by taking into account the pressure dependence of the latent heat of the product that was used (Tylose). The effect of pressure on the latent heat of Tylose was experimentally determined by a series of freezing experiments conducted at different pressure levels. By combining a numerical heat transfer model for freezing processes with a least sum of squares optimization procedure, the corresponding latent heat at each pressure level was estimated, and the obtained pressure relation was incorporated in the original high-pressure thawing model. Excellent agreement with the experimental temperature profiles for both high-pressure freezing and thawing was observed.

Determination of heat transfer coefficient for an interaction of sub-cooled gas and metal

NASA Astrophysics Data System (ADS)

Zaidi Sidek, Mohd; Syahidan Kamarudin, Muhammad

2016-02-01

Heat transfer coefficient (HTC) for a hot metal surface and their surrounding is one of the need be defined parameter in hot forming process. This study has been conducted to determine the HTC for an interaction between sub-cooled gas sprayed on a hot metal surface. Both experiments and finite element have been adopted in this work. Initially, the designated experiment was conducted to obtain temperature history of spray cooling process. Then, an inverse method was adopted to calculate the HTC value before we validate in a finite element simulation model. The result shows that the heat transfer coefficient for interaction of subcooled gas and hot metal surface is 1000 W/m2K.

High Power Ion Cyclotron Heating in the VASIMR

NASA Astrophysics Data System (ADS)

Longmier, B. W.; Brukardt, M. S.; Bering, E. A.; Chang Diaz, F.; Squire, J.

2009-12-01

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) is an electric propulsion system under development at Ad Astra Rocket Company that utilizes several processes of ion acceleration and heating that occur in the Birkeland currents of an auroral arc system. Among these processes are parallel electric field acceleration, lower hybrid resonance heating, and ion cyclotron resonance heating. The VASIMR® is capable of laboratory simulation of electromagnetic ion cyclotron wave heating during a single pass of ions through the resonance region. The plasma is generated by a helicon discharge of 35 kW then passes through a 176 kW RF booster stage that couples left hand polarized slow mode waves from the high field side of the resonance. VX-200 auroral simulation results from the past year are discussed. Ambipolar acceleration has been shown to produce 35eV argon ions in the helicon exhaust. The effects on the ion exhaust with an addition of 150-200 kW of ion cyclotron heating are presented. The changes to the VASIMR® experiment at Ad Astra Rocket Company's new facility in Webster, Texas will also be discussed, including the possibility of collaborative experiments.

Charging and Discharging Processes of Thermal Energy Storage System Using Phase change materials

NASA Astrophysics Data System (ADS)

Kanimozhi, B., Dr.; Harish, Kasilanka; Sai Tarun, Bellamkonda; Saty Sainath Reddy, Pogaku; Sai Sujeeth, Padakandla

2017-05-01

The objective of the study is to investigate the thermal characteristics of charging and discharge processes of fabricated thermal energy storage system using Phase change materials. Experiments were performed with phase change materials in which a storage tank have designed and developed to enhance the heat transfer rate from the solar tank to the PCM storage tank. The enhancement of heat transfer can be done by using a number of copper tubes in the fabricated storage tank. This storage tank can hold or conserve heat energy for a much longer time than the conventional water storage system. Performance evaluations of experimental results during charging and discharging processes of paraffin wax have discussed. In which heat absorption and heat rejection have been calculated with various flow rate.

On the development of nugget growth model for resistance spot welding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Kang, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk; Cai, Lilong, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk

2014-04-28

In this paper, we developed a general mathematical model to estimate the nugget growth process based on the heat energy delivered into the welds by the resistance spot welding. According to the principles of thermodynamics and heat transfer, and the effect of electrode force during the welding process, the shape of the nugget can be estimated. Then, a mathematical model between heat energy absorbed and nugget diameter can be obtained theoretically. It is shown in this paper that the nugget diameter can be precisely described by piecewise fractal polynomial functions. Experiments were conducted with different welding operation conditions, such asmore » welding currents, workpiece thickness, and widths, to validate the model and the theoretical analysis. All the experiments confirmed that the proposed model can predict the nugget diameters with high accuracy based on the input heat energy to the welds.« less

Numerical simulation of the alloying process during impulse induction heating of the metal substrate

NASA Astrophysics Data System (ADS)

Popov, V. N.

2017-10-01

2D numerical modeling of the processes during the alloying of the substrate surface metal layer is carried out. Heating, phase transition, heat and mass transfer in the molten metal, solidification of the melt are considered with the aid the proposed mathematical model. Under study is the applicability of the high-frequency electromagnetic field impulse for metal heating and melting. The distribution of the electromagnetic energy in the metal is described by empirical formulas. According to the results of numerical experiments, the flow structure in the melt and distribution of the alloying substances is evaluated.

Heat treatment study 2

NASA Technical Reports Server (NTRS)

Workman, Gary L.

1990-01-01

The microstructural variations in nickel based superalloys that result from modifications in processing were examined. These superalloys include MAR-M246(HF) and PWA1480. Alternate heat treatments for equiaxed as-cast specimens were studied and a sample matrix of 42 variations in the heat treatments were processed, as well as different directional solidification parameters. Variation in temperature and times for both solution and aging were performed. Photomicrographs were made of the microstructure and volume fraction analysis of primary gamma-prime and aged gamma-prime precipitates were performed. The results of the heat treatment, cooling rate, and directional solidification experiments are discussed.

Radiation-Thermal Sintering of Zirconia Powder Compacts Under Conditions of Bilateral Heating Using Beams of Low-Energy Electrons

NASA Astrophysics Data System (ADS)

Ghyngazov, S. A.; Frangulyan, T. S.; Chernyavskii, A. V.; Goreev, A. K.; Naiden, E. P.

2015-06-01

Comparative experiments on sintering zirconia ceramics are performed using colliding beams of low-energy electrons and under conditions of thermal heating. The density and microhardness of ceramic materials manufactured via different processes are determined. The use of a regime of bilateral heating by high-intensity,low-energy electron beams is shown to intensify the sintering process and yield material specimens with improved characteristics compared to those formed by thermal sintering.

Heat transfer characteristics of building walls using phase change material

NASA Astrophysics Data System (ADS)

Irsyad, M.; Pasek, A. D.; Indartono, Y. S.; Pratomo, A. W.

2017-03-01

Minimizing energy consumption in air conditioning system can be done with reducing the cooling load in a room. Heat from solar radiation which passes through the wall increases the cooling load. Utilization of phase change material on walls is expected to decrease the heat rate by storing energy when the phase change process takes place. The stored energy is released when the ambient temperature is low. Temperature differences at noon and evening can be utilized as discharging and charging cycles. This study examines the characteristics of heat transfer in walls using phase change material (PCM) in the form of encapsulation and using the sleeve as well. Heat transfer of bricks containing encapsulated PCM, tested the storage and released the heat on the walls of the building models were evaluated in this study. Experiments of heat transfer on brick consist of time that is needed for heat transfer and thermal conductivity test as well. Experiments were conducted on a wall coated by PCM which was exposed on a day and night cycle to analyze the heat storage and heat release. PCM used in these experiments was coconut oil. The measured parameter is the temperature at some points in the brick, walls and ambient temperature as well. The results showed that the use of encapsulation on an empty brick can increase the time for thermal heat transfer. Thermal conductivity values of a brick containing encapsulated PCM was lower than hollow bricks, where each value was 1.3 W/m.K and 1.6 W/m.K. While the process of heat absorption takes place from 7:00 am to 06:00 pm, and the release of heat runs from 10:00 pm to 7:00 am. The use of this PCM layer can reduce the surface temperature of the walls of an average of 2°C and slows the heat into the room.

Analysis of collapse in flattening a micro-grooved heat pipe by lateral compression

NASA Astrophysics Data System (ADS)

Li, Yong; He, Ting; Zeng, Zhixin

2012-11-01

The collapse of thin-walled micro-grooved heat pipes is a common phenomenon in the tube flattening process, which seriously influences the heat transfer performance and appearance of heat pipe. At present, there is no other better method to solve this problem. A new method by heating the heat pipe is proposed to eliminate the collapse during the flattening process. The effectiveness of the proposed method is investigated through a theoretical model, a finite element(FE) analysis, and experimental method. Firstly, A theoretical model based on a deformation model of six plastic hinges and the Antoine equation of the working fluid is established to analyze the collapse of thin walls at different temperatures. Then, the FE simulation and experiments of flattening process at different temperatures are carried out and compared with theoretical model. Finally, the FE model is followed to study the loads of the plates at different temperatures and heights of flattened heat pipes. The results of the theoretical model conform to those of the FE simulation and experiments in the flattened zone. The collapse occurs at room temperature. As the temperature increases, the collapse decreases and finally disappears at approximately 130 °C for various heights of flattened heat pipes. The loads of the moving plate increase as the temperature increases. Thus, the reasonable temperature for eliminating the collapse and reducing the load is approximately 130 °C. The advantage of the proposed method is that the collapse is reduced or eliminated by means of the thermal deformation characteristic of heat pipe itself instead of by external support. As a result, the heat transfer efficiency of heat pipe is raised.

Induction hardening: Differences to a conventional heat treatment process and optimization of its parameters

NASA Astrophysics Data System (ADS)

Vieweg, A.; Ressel, G.; Prevedel, P.; Raninger, P.; Panzenböck, M.; Marsoner, S.; Ebner, R.

2016-03-01

The possibility of obtaining similar mechanical properties with faster heating processes than the conventional ones has been of interest for several years. In the present study, investigations were performed in terms of the influences of such fast heat-treatments on the microstructure and mechanical properties of the material. This investigation compares an inductive with a conventional furnace heat treating process of a 50CrMo4 steel, however only the austenitizing treatment was changed and subsequent quenching and tempering was done in the same way. To this end experiments with a middle frequency generator, using different heating rates and austenitizing temperatures, were conducted and followed by oil quenching of the workpieces. The resulting structures were characterized regarding their microstructures and mechanical properties in order to gather a better understanding of the differences between the inductive and the conventional heat treating process. As a main result it was found, that the fast austenitized samples exhibited worse ductility than the conventional treated material.

Some limitations on processing materials in acoustic levitation devices

NASA Technical Reports Server (NTRS)

Oran, W. A.; Witherow, W. K.; Ross, B. B.; Rush, J. E.

1979-01-01

The spot heating of samples, suspended in an acoustic field, was investigated to determine if the technique could be used to process materials. A single axis resonance device operating in air at 25 C with an rms pressure maximum of 160 to 170 db was used in the experiments. The heat flow from a hot object suspended in a levitation node is dominated by the effects of the field, with the heat loss approximately 20 times larger than that due to natural convection. The acoustic forces which suspend the body at a node also serve to eject the heated air. The coupling between the locally heated region around the body and the acoustic field results in instabilities in both the pressure wave and force field. The investigations indicated the extreme difficulties in developing a materials processing device based on acoustic/spot heating for use in a terrestrial environment.

Orion Heat Shield Manufacturing Producibility Improvements for the EM-1 Flight Test Program

NASA Technical Reports Server (NTRS)

Koenig, William J.; Stewart, Michael; Harris, Richard F.

2018-01-01

This paper describes how the ORION program is incorporating improvements in the heat shield design and manufacturing processes reducing programmatic risk and ensuring crew safety in support of NASA's Exploration missions. The approach for the EFT-1 heat shield utilized a low risk Apollo heritage design and manufacturing process using an Avcoat TPS ablator with a honeycomb substrate to provide a one piece heat shield to meet the mission re-entry heating environments. The EM-1 mission will have additional flight systems installed to fly to the moon and return to Earth. Heat shield design and producibility improvements have been incorporated in the EM-1 vehicle to meet deep space mission requirements. The design continues to use the Avcoat material, but in a block configuration to enable improvements in consistant and repeatable application processes using tile bonding experience developed on the Space Shuttle Transportation System Program.

Electromagnetic containerless undercooling facility and experiments for the Shuttle

NASA Technical Reports Server (NTRS)

Frost, R. T.; Flemings, M. C.; Szekely, J.; El-Kaddah, N.; Shiohara, Y.

1984-01-01

An electromagnetic furnace is being prepared for flights aboard the Space Shuttle. This apparatus is capable of melting metals and alloys up to 1400 C melting point by induction heating with subsequent solidification of the freely levitated melt without contact with any container. The solidification can be carried out with greatly reduced fields resulting in minimal heating and stirring of the free melt. Sequential specimens can be processed during flight. Several experiments are planned for a series of flights, beginning in 1985 with an undercooling experiment of NiSn alloys. These will be interspersed with detailed studies of fluid flow caused by low and high field levels in order to quantify the corresponding effect upon the solidification process.

Design and test of a compact optics system for the pool boiling experiment

NASA Technical Reports Server (NTRS)

Ling, Jerri S.; Laubenthal, James R.

1990-01-01

The experiment described seeks to improve the understanding of the fundamental mechanisms that constitute nucleate pool boiling. The vehicle for accomplishing this is an investigation, including tests to be conducted in microgravity and coupled with appropriate analyses, of the heat transfer and vapor bubble dynamics associated with nucleation, bubble growth/collapse and subsequent motion, considering the interrelations between buoyancy, momentum and surface tension which will govern the motion of the vapor and surrounding liquid, as a function of the heating rate at the heat transfer surface and the temperature level and distribution in the bulk liquid. The experiment is designed to be contained within the confines of a Get-Away-Special Canister (GAS Can) installed in the bay of the space shuttle. When the shuttle reaches orbit, the experiment will be turned on and testing will proceed automatically. In the proposed Pool Boiling Experiment a pool of liquid, initially at a precisely defined pressure and temperature, will be subjected to a step imposed heat flux from a semitransparent thin-film heater forming part of one wall of the container such that boiling is initiated and maintained for a defined period of time at a constant pressure level. Transient measurements of the heater surface and fluid temperatures near the surface will be made, noting especially the conditions at the onset of boiling, along with motion photography of the boiling process in two simultaneous views, from beneath the heating surface and from the side. The conduct of the experiment and the data acquisition will be completely automated and self-contained. For the initial flight, a total of nine tests are proposed, with three levels of heat flux and three levels of subcooling. The design process used in the development and check-out of the compact photographic/optics system for the Pool Boiling Experiment is documented.

Study of Variable Frequency Induction Heating in Steel Making Process

NASA Astrophysics Data System (ADS)

Fukutani, Kazuhiko; Umetsu, Kenji; Itou, Takeo; Isobe, Takanori; Kitahara, Tadayuki; Shimada, Ryuichi

Induction heating technologies have been the standard technologies employed in steel making processes because they are clean, they have a high energy density, they are highly the controllable, etc. However, there is a problem in using them; in general, frequencies of the electric circuits have to be kept fixed to improve their power factors, and this constraint makes the processes inflexible. In order to overcome this problem, we have developed a new heating technique-variable frequency power supply with magnetic energy recovery switching. This technique helps us in improving the quality of steel products as well as the productivity. We have also performed numerical calculations and experiments to evaluate its effect on temperature distributions on heated steel plates. The obtained results indicate that the application of the technique in steel making processes would be advantageous.

Multiphysics numerical modeling of the continuous flow microwave-assisted transesterification process.

PubMed

Muley, Pranjali D; Boldor, Dorin

2012-01-01

Use of advanced microwave technology for biodiesel production from vegetable oil is a relatively new technology. Microwave dielectric heating increases the process efficiency and reduces reaction time. Microwave heating depends on various factors such as material properties (dielectric and thermo-physical), frequency of operation and system design. Although lab scale results are promising, it is important to study these parameters and optimize the process before scaling up. Numerical modeling approach can be applied for predicting heating and temperature profiles including at larger scale. The process can be studied for optimization without actually performing the experiments, reducing the amount of experimental work required. A basic numerical model of continuous electromagnetic heating of biodiesel precursors was developed. A finite element model was built using COMSOL Multiphysics 4.2 software by coupling the electromagnetic problem with the fluid flow and heat transfer problem. Chemical reaction was not taken into account. Material dielectric properties were obtained experimentally, while the thermal properties were obtained from the literature (all the properties were temperature dependent). The model was tested for the two different power levels 4000 W and 4700 W at a constant flow rate of 840ml/min. The electric field, electromagnetic power density flow and temperature profiles were studied. Resulting temperature profiles were validated by comparing to the temperatures obtained at specific locations from the experiment. The results obtained were in good agreement with the experimental data.

Surface energy and radiation balance systems - General description and improvements

NASA Technical Reports Server (NTRS)

Fritschen, Leo J.; Simpson, James R.

1989-01-01

Surface evaluation of sensible and latent heat flux densities and the components of the radiation balance were desired for various vegetative surfaces during the ASCOT84 experiment to compare with modeled results and to relate these values to drainage winds. Five battery operated data systems equipped with sensors to determine the above values were operated for 105 station days during the ASCOT84 experiment. The Bowen ratio energy balance technique was used to partition the available energy into the sensible and latent heat flux densities. A description of the sensors and battery operated equipment used to collect and process the data is presented. In addition, improvements and modifications made since the 1984 experiment are given. Details of calculations of soil heat flow at the surface and an alternate method to calculate sensible and latent heat flux densities are provided.

Development and test of combustion chamber for Stirling engine heated by natural gas

NASA Astrophysics Data System (ADS)

Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

2014-04-01

The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

General purpose rocket furnace

NASA Technical Reports Server (NTRS)

Aldrich, B. R.; Whitt, W. D. (Inventor)

1979-01-01

A multipurpose furnace for space vehicles used for material processing experiments in an outer space environment is described. The furnace contains three separate cavities designed to process samples of the widest possible range of materials and thermal requirements. Each cavity contains three heating elements capable of independent function under the direction of an automatic and programmable control system. A heat removable mechanism is also provided for each cavity which operates in conjunction with the control system for establishing an isothermally heated cavity or a wide range of thermal gradients and cool down rates. A monitoring system compatible with the rocket telemetry provides furnace performance and sample growth rate data throughout the processing cycle.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehl, M; Kukkadapu, G; Kumar, K

The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history duringmore » ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first-stage (when observed) and second-stage ignition delay times and of heat release rate. The experimental and computational results are used to gain insight into low and intermediate temperature processes during gasoline ignition.« less

Condensation of vapor bubble in subcooled pool

NASA Astrophysics Data System (ADS)

Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

2017-02-01

We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

A Modeling Study of Oceanic Response to Daily and Monthly Surface Forcing

NASA Technical Reports Server (NTRS)

Sui, Chung-Hsiung; Li, Xiao-Fan; Rienecker, Michele M.; Lau, William K.-M.; Einaudi, Franco (Technical Monitor)

2001-01-01

The goal of this study is to investigate the effect of high-frequency surface forcing (wind stresses and heat fluxes) on upper-ocean response. We use the reduced-gravity quasi-isopycnal ocean model by Schopf and Loughe (1995) for this study. Two experiments are performed: one with daily and the other with monthly surface forcing. The two experiments are referred to as DD and MM, respectively. The daily surface wind stress is produced from the SSM/I wind data (Atlas et al. 1991) using the drag coefficient of Large and Pond (1982). The surface latent and sensible heat fluxes are estimated using the atmospheric mixed layer model by Seager et al. (1995) with the time-varying air temperature and specific humidity from the NCEP-NCAR reanalysis (Kalnay et al. 1996). The radiation is based on climatological shortwave radiation from the Earth Radiation Budget Experiment (ERBE) [Harrison et al. 1993] and the daily GEWEX SRB data. The ocean model domain is restricted to the Pacific Ocean with realistic land boundaries. At the southern boundary the model temperature and salinity are relaxed to the Levitus (1994) climatology. The time-mean SST distribution from MM is close to the observed SST climatology while the mean SST field from DD is about 1.5 C cooler. To identify the responsible processes, we examined the mean heat budgets and the heat balance during the first year (when the difference developed) in the two experiments. The analysis reveals that this is contributed by two factors. One is the difference in latent heat flux. The other is the difference in mixing processes. To further evaluate the responsible processes, we repeated the DD experiment by reducing the based vertical diffusion from 1e-4 to 0.5e-5. The resultant SST field becomes quite closer to the observed SST field. SST variability from the two experiments is generally similar, but the equatorial SST differences between the two experiments show interannual variations. We are investigating the possible mechanisms responsible for the different responses.

Slow Impacts on Strong Targets Bring on the Heat

NASA Astrophysics Data System (ADS)

Melosh, H. J.; Ivanov, B. A.

2018-03-01

An important new paper by Kurosawa and Genda (2017, https://doi.org/10.1002/2017GL076285) reports a previously overlooked source of heating in low velocity meteorite impacts. Plastic deformation of the pressure-strengthened rocks behind the shock front dissipates energy, which appears as heat in addition to that generated across the shock wave itself. This heat source has surprisingly escaped explicit attention for decades: First, because it is minimized in the geometry typically chosen for laboratory experiments; and second because it is most important in rocks, and less so for the metals usually used in experiments. Nevertheless, modern numerical computer codes that include strength do compute this heating correctly. This raises the philosophical question of whether we can claim to understand some process just because our computer codes compute the results correctly.

Generation of whistler waves by continuous HF heating of the upper ionosphere

NASA Astrophysics Data System (ADS)

Vartanyan, A.; Milikh, G. M.; Eliasson, B. E.; Sharma, A.; Chang, C.; Parrot, M.; Papadopoulos, K.

2013-12-01

We report observations of VLF waves by the DEMETER satellite overflying the HAARP facility during ionospheric heating experiments. The detected VLF waves were in the range 8-17 kHz and coincided with times of continuous heating. The experiments indicate whistler generation due to conversion of artificial lower hybrid waves to whistlers on small scale field-aligned plasma density striations. The observations are compared with theoretical models, taking into account both linear and nonlinear processes. Implications of the mode conversion technique on VLF generation with subsequent injection into the radiation belts to trigger particle precipitation are discussed.

Scaling water and energy fluxes in climate systems - Three land-atmospheric modeling experiments

NASA Technical Reports Server (NTRS)

Wood, Eric F.; Lakshmi, Venkataraman

1993-01-01

Three numerical experiments that investigate the scaling of land-surface processes - either of the inputs or parameters - are reported, and the aggregated processes are compared to the spatially variable case. The first is the aggregation of the hydrologic response in a catchment due to rainfall during a storm event and due to evaporative demands during interstorm periods. The second is the spatial and temporal aggregation of latent heat fluxes, as calculated from SiB. The third is the aggregation of remotely sensed land vegetation and latent and sensible heat fluxes using TM data from the FIFE experiment of 1987 in Kansas. In all three experiments it was found that the surface fluxes and land characteristics can be scaled, and that macroscale models based on effective parameters are sufficient to account for the small-scale heterogeneities investigated.

Harwell high pressure heat transfer loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, A.W.; Keeys, R.K.F.

1967-12-15

A detailed description is presented of the Harwell (Chemical Engineering and Process Technology Division) high pressure, steam-water heat transfer loop; this description is aimed at supplementing the information given in reports on individual experiments. The operating instructions for the loop are given in an appendix. (auth)

Conceptual design for spacelab pool boiling experiment

NASA Technical Reports Server (NTRS)

Lienhard, J. H.; Peck, R. E.

1978-01-01

A pool boiling heat transfer experiment to be incorporated with a larger two-phase flow experiment on Spacelab was designed to confirm (or alter) the results of earth-normal gravity experiments which indicate that the hydrodynamic peak and minimum pool boiling heat fluxes vanish at very low gravity. Twelve small sealed test cells containing water, methanol or Freon 113 and cylindrical heaters of various sizes are to be built. Each cell will be subjected to one or more 45 sec tests in which the surface heat flux on the heaters is increased linearly until the surface temperature reaches a limiting value of 500 C. The entire boiling process will be photographed in slow-motion. Boiling curves will be constructed from thermocouple and electric input data, for comparison with the motion picture records. The conduct of the experiment will require no more than a few hours of operator time.

View of equipment used for Heat Flow and Convection Experiment

NASA Image and Video Library

1972-12-17

AS17-162-24063 (7-19 Dec. 1972) --- A close-up view of the equipment used for the Heat Flow and Convection Experiment, an engineering and operational test and demonstration carried out aboard the Apollo 17 command module during the final lunar landing mission in NASA's Apollo program. Three test cells were used in the demonstration for measuring and observing fluid flow behavior in the absence of gravity in space flight. Data obtained from such demonstrations will be valuable in the design of future science experiments and for manufacturing processes in space.

Influence of collector heat capacity and internal conditions of heat exchanger on cool-down process of small gas liquefier

NASA Astrophysics Data System (ADS)

Saberimoghaddam, Ali; Bahri Rasht Abadi, Mohammad Mahdi

2018-01-01

Joule-Thomson cooling systems are commonly used in gas liquefaction. In small gas liquefiers, transient cool-down time is high. Selecting suitable conditions for cooling down process leads to decrease in time and cost. In the present work, transient thermal behavior of Joule-Thomson cooling system including counter current helically coiled tube in tube heat exchanger, expansion valve, and collector was studied using experimental tests and simulations. The experiments were performed using small gas liquefier and nitrogen gas as working fluid. The heat exchanger was thermally studied by experimental data obtained from a small gas liquefier. In addition, the simulations were performed using experimental data as variable boundary conditions. A comparison was done between presented and conventional methods. The effect of collector heat capacity and convection heat transfer coefficient inside the tubes on system performance was studied using temperature profiles along the heat exchanger.

Adsorptive Water Removal from Dichloromethane and Vapor-Phase Regeneration of a Molecular Sieve 3A Packed Bed

PubMed Central

2017-01-01

The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation of the experiments. The breakthrough curves are adequately described by a mathematical model that includes external mass transfer, pore diffusion, and surface diffusion. During the desorption step, the main heat transfer mechanism is the condensation of the superheated dichloromethane vapor. The regeneration time is shortened significantly by external bed heating. Cyclic steady-state experiments demonstrate the feasibility of this novel, zero-emission drying process. PMID:28539701

Estimation and Optimization of the Parameters Preserving the Lustre of the Fabrics

NASA Astrophysics Data System (ADS)

Prodanova, Krasimira

2009-11-01

The paper discusses the optimization of the continuance of the Damp-Heating Process of a steaming iron press machine, and the preserving of the lustre of the fabrics. In order to be obtained high qualitative damp-heating processing, it is necessary to monitor parameters such as temperature, damp, and pressure during the process. The purpose of the present paper is a mathematical model to be constructed that adequately describes the technological process using multivariate data analysis. It was established that the full factorial design of type 23 is not adequate. The research has proceeded with central rotatable design of experiment. The obtained model adequately describes the technological process of damp-heating treatment in the defined factor space. The present investigation is helpful to the technological improvement and modernization in sewing companies.

Processing and refinement of steel microstructure images for assisting in computerized heat treatment of plain carbon steel

NASA Astrophysics Data System (ADS)

Gupta, Shubhank; Panda, Aditi; Naskar, Ruchira; Mishra, Dinesh Kumar; Pal, Snehanshu

2017-11-01

Steels are alloys of iron and carbon, widely used in construction and other applications. The evolution of steel microstructure through various heat treatment processes is an important factor in controlling properties and performance of steel. Extensive experimentations have been performed to enhance the properties of steel by customizing heat treatment processes. However, experimental analyses are always associated with high resource requirements in terms of cost and time. As an alternative solution, we propose an image processing-based technique for refinement of raw plain carbon steel microstructure images, into a digital form, usable in experiments related to heat treatment processes of steel in diverse applications. The proposed work follows the conventional steps practiced by materials engineers in manual refinement of steel images; and it appropriately utilizes basic image processing techniques (including filtering, segmentation, opening, and clustering) to automate the whole process. The proposed refinement of steel microstructure images is aimed to enable computer-aided simulations of heat treatment of plain carbon steel, in a timely and cost-efficient manner; hence it is beneficial for the materials and metallurgy industry. Our experimental results prove the efficiency and effectiveness of the proposed technique.

Heat treatment of wet wood fiber: A study of the effect of reaction conditions on the formation of furfurals

Treesearch

Mandla A. Tshabalala; James D. McSweeny; Roger M. Rowell

2012-01-01

Furan monomers are produced when wood is heated at high temperatures. To understand the process conditions for production of furfural (FF) and hydroxymethylfurfural (HMF) from wood, samples of milled aspen wood were subjected to autohydrolyzis by microwave heating in a sealed Teflon reactor. The experiments were designed to simulate temperature and pressure variables...

Design analysis of levitation facility for space processing applications. [Skylab program, space shuttles

NASA Technical Reports Server (NTRS)

Frost, R. T.; Kornrumpf, W. P.; Napaluch, L. J.; Harden, J. D., Jr.; Walden, J. P.; Stockhoff, E. H.; Wouch, G.; Walker, L. H.

1974-01-01

Containerless processing facilities for the space laboratory and space shuttle are defined. Materials process examples representative of the most severe requirements for the facility in terms of electrical power, radio frequency equipment, and the use of an auxiliary electron beam heater were used to discuss matters having the greatest effect upon the space shuttle pallet payload interfaces and envelopes. Improved weight, volume, and efficiency estimates for the RF generating equipment were derived. Results are particularly significant because of the reduced requirements for heat rejection from electrical equipment, one of the principal envelope problems for shuttle pallet payloads. It is shown that although experiments on containerless melting of high temperature refractory materials make it desirable to consider the highest peak powers which can be made available on the pallet, total energy requirements are kept relatively low by the very fast processing times typical of containerless experiments and allows consideration of heat rejection capabilities lower than peak power demand if energy storage in system heat capacitances is considered. Batteries are considered to avoid a requirement for fuel cells capable of furnishing this brief peak power demand.

Physical modeling and monitoring of the process of thermal-erosion of an ice-wedge during a partially-controlled field experiment (Bylot Island, NU, Canada)

NASA Astrophysics Data System (ADS)

Godin, E.; Fortier, D.

2013-12-01

Syngenetic ice-wedges polygons are widespread periglacial features of the Arctic. On Bylot Island, Nunavut, Canada, numerous thermo-erosion gullies up to several 100's m in length developed in polygonal wetlands during the last decades. These gullies contributed to drainage of these wetlands and changed dramatically local ecological conditions. Concentrated and repeated snowmelt surface runoff infiltrated frost cracks, where convective heat transfer between flowing water and ice initiated piping in ice wedges leading to the rapid development of tunnels and gullies in the permafrost (Fortier D. et al., 2007). We conducted field experiments to quantify the convection process and speed of ice wedges ablation. The experiments were accomplished between the 23/06/2013 and the 05/07/2013 over A; an exposed sub-horizontal ice-wedge surface and B; a tunnel in an ice-wedge crack. The ice was instrumented with graduated sticks to calculate the ice ablation following the flow of a defined amount of water. A fixed quantity of water obtained from a nearby waterfall was diverted over the ice through a PVC pipe. Water temperature Wt (K), quantity Wq (L s-1 or m3 s-1), ice ablation rate Iar (m s-1) and convective heat transfer coefficient α (W m-2 K) were obtained during the 5 experiments. The objective of this paper is to quantify the heat transfer process from field measurements from an ice wedge under ablation and to compare with coefficients from previous researches and in the literature. For each experiment with the ice-surface scenario, water temperature varied between 280 K and 284 K. Discharge varied between 0.0001 and 0.0003 m3 s-1. Ablation rate varied between 1.8 * 10-5 and 0.0004 m s-1. Heat transfer coefficient varied between 706 and 11 655 W m-2 K and between 54 and 4802 W of heat was transferred to ice. For each experiment with the tunnel scenario, water temperature was 284 K × 1 K. Discharge was 0.0002 m3 s-1. Ablation rate varied between 0.0001 and 0.0003 m s-1. Heat transfer coefficient varied between 2644 and 7934 W m-2 K and between 1791 and 5374 W of heat was transferred to ice. Water temperature exiting the tunnel was less than 279 K. Both contexts of experimentation are occurring frequently during gully development. A small input of water over exposed massive-ice can erode significant volume of ice-wedges ice, thermally and mechanically. Empiric determination of the heat transfer coefficient using the parameters measured in the field will provide a better understanding of water temperature and discharge relative importance in the thermo-erosion of ice. Fortier, D., Allard, M., et al. (2007). "Observation of rapid drainage system development by thermal erosion of ice wedges on Bylot island, Canadian Arctic Archipelago." Permafrost and Periglacial Processes 18(3): 229-243.

Modeling of laser transmission contour welding process using FEA and DoE

NASA Astrophysics Data System (ADS)

Acherjee, Bappa; Kuar, Arunanshu S.; Mitra, Souren; Misra, Dipten

2012-07-01

In this research, a systematic investigation on laser transmission contour welding process is carried out using finite element analysis (FEA) and design of experiments (DoE) techniques. First of all, a three-dimensional thermal model is developed to simulate the laser transmission contour welding process with a moving heat source. The commercial finite element code ANSYS® multi-physics is used to obtain the numerical results by implementing a volumetric Gaussian heat source, and combined convection-radiation boundary conditions. Design of experiments together with regression analysis is then employed to plan the experiments and to develop mathematical models based on simulation results. Four key process parameters, namely power, welding speed, beam diameter, and carbon black content in absorbing polymer, are considered as independent variables, while maximum temperature at weld interface, weld width, and weld depths in transparent and absorbing polymers are considered as dependent variables. Sensitivity analysis is performed to determine how different values of an independent variable affect a particular dependent variable.

Whole body heat stress increases motor cortical excitability and skill acquisition in humans

PubMed Central

Littmann, Andrew E.; Shields, Richard K.

2015-01-01

Objective Vigorous systemic exercise stimulates a cascade of molecular and cellular processes that enhance central nervous system (CNS) plasticity and performance. The influence of heat stress on CNS performance and learning is novel. We designed two experiments to determine whether passive heat stress 1) facilitated motor cortex excitability and 2) improved motor task acquisition compared to no heat stress. Methods Motor evoked potentials (MEPs) from the first dorsal interosseus (FDI) were collected before and after 30 minutes of heat stress at 73° C. A second cohort of subjects performed a motor learning task using the FDI either following heat or the no heat condition. Results Heat stress increased heart rate to 65% of age-predicted maximum. After heat, mean resting MEP amplitude increased 48% (P < 0.05). MEP stimulus-response amplitudes did not differ according to stimulus intensity. In the second experiment, heat stress caused a significant decrease in absolute and variable error (p < 0.05) during a novel movement task using the FDI. Conclusions Passive environmental heat stress 1) increases motor cortical excitability, and 2) enhances performance in a motor skill acquisition task. Significance Controlled heat stress may prime the CNS to enhance motor skill acquisition during rehabilitation. PMID:26616546

Preliminary Results on Thermal Shock Behavior of CuZnAl Shape Memory Alloy Using a Solar Concentrator as Heating Source

NASA Astrophysics Data System (ADS)

Tudora, C.; Abrudeanu, M.; Stanciu, S.; Anghel, D.; Plaiaşu, G. A.; Rizea, V.; Ştirbu, I.; Cimpoeşu, N.

2018-06-01

It is highly accepted that martensitic transformation can be induced by temperature variation and by stress solicitation. Using a solar concentrator, we manage to increase the material surface temperature (till 573 respectively 873 K) in very short periods of time in order to analyze the material behavior under thermal shocks. The heating/cooling process was registered and analyzed during the experiments. Material surface was analyzed before and after thermal shocks by microstructure point of view using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The experiments follow the material behavior during fast heating and propose the possibility of activating smart materials using the sun heat for aerospace applications.

Experimental approach for thermal parameters estimation during glass forming process

NASA Astrophysics Data System (ADS)

Abdulhay, B.; Bourouga, B.; Alzetto, F.; Challita, C.

2016-10-01

In this paper, an experimental device designed and developedto estimate thermal conditions at the Glass / piston contact interface is presented. This deviceis made of two parts: the upper part contains the piston made of metal and a heating device to raise the temperature of the piston up to 500 °C. The lower part is composed of a lead crucible and a glass sample. The assembly is provided with a heating system, an induction furnace of 6 kW for heating the glass up to 950 °C.The developed experimental procedure has permitted in a previous published study to estimate the Thermal Contact ResistanceTCR using the inverse technique developed by Beck [1]. The semi-transparent character of the glass has been taken into account by an additional radiative heat flux and an equivalent thermal conductivity. After the set-up tests, reproducibility experiments for a specific contact pressure have been carried outwith a maximum dispersion that doesn't exceed 6%. Then, experiments under different conditions for a specific glass forming process regarding the application (Packaging, Buildings and Automobile) were carried out. The objective is to determine, experimentallyfor each application,the typical conditions capable to minimize the glass temperature loss during the glass forming process.

Effect of heating rate on thermal cracking characteristics and kinetics of Xinjiang oil sand bitumen by TG-FTIR

NASA Astrophysics Data System (ADS)

Hao, Junhui; Zhang, Jinhong; Qiao, Yingyun; Tian, Yuanyu

2017-08-01

This work was aimed to investigate effects of heating rate on thermal cracking behaviors, distribution of gaseous products and activation energy of the thermal cracking process of Xinjiang oil sand bitumen (OSB). The thermal cracking experiments of Xinjiang OSB were performed by using thermogravimetric analyzer (TGA) at various heating rates of 10, 20, 50, 80 and 120 K/min. The evolving characteristic of gaseous products produced from the thermal cracking process was evaluated by the Fourier transform infrared spectrometry (FTIR) connected with TG. The kinetic parameters of the thermal cracking process of Xinjiang OSB at each of heating rate were determined by the Coats-Redfern model. The result show that the temperature intervals of DE volatilization stage and main reaction stage, the ((dw/dt) max and Tmax in thermal cracking process of Xinjiang OSB all increased with the increasing heating rate. While the heating rate has not obvious effect on the coke yield of Xinjiang OSB. Furthermore, the maximum absorbance of gaseous products and corresponding temperature became larger as the heating rate increases. The activation energy of this two stage both presented increasing trend with the rising heating rate, while the increasing content of that of DE volatilization stage was weaker compared to that of main reaction stage.

Interaction of adhered metallic dust with transient plasma heat loads

NASA Astrophysics Data System (ADS)

Ratynskaia, S.; Tolias, P.; Bykov, I.; Rudakov, D.; De Angeli, M.; Vignitchouk, L.; Ripamonti, D.; Riva, G.; Bardin, S.; van der Meiden, H.; Vernimmen, J.; Bystrov, K.; De Temmerman, G.

2016-06-01

The first study of the interaction of metallic dust (tungsten, aluminum) adhered on tungsten substrates with transient plasma heat loads is presented. Experiments were carried out in the Pilot-PSI linear device with transient heat fluxes up to 550 MW m-2 and in the DIII-D divertor tokamak. The central role of the dust-substrate contact area in heat conduction is highlighted and confirmed by heat transfer simulations. The experiments provide evidence of the occurrence of wetting-induced coagulation, a novel growth mechanism where cluster melting accompanied by droplet wetting leads to the formation of larger grains. The physical processes behind this mechanism are elucidated. The remobilization activity of the newly formed dust and the survivability of tungsten dust on hot surfaces are documented and discussed in the light of implications for ITER.

[Acceleration of osmotic dehydration process through ohmic heating of foods: raspberries (Rubus idaeus)].

PubMed

Simpson, Ricardo R; Jiménez, Maite P; Carevic, Erica G; Grancelli, Romina M

2007-06-01

Raspberries (Rubus idaeus) were osmotically dehydrated by applying a conventional method under the supposition of a homogeneous solution, all in a 62% glucose solution at 50 degrees C. Raspberries (Rubus idaeus) were also osmotically dehydrated by using ohmic heating in a 57% glucose solution at a variable voltage (to maintain temperature between 40 and 50 degrees C) and an electric field intensity <100 V/cm. When comparing the results from both experiments it was evident that processing time is reduced when ohmic heating technique was used. In some cases this reduction reached even 50%. This is explained by the additional effect to the thermal damage that is generated in an ohmic process, denominated electroporation.

Numerical and experimental analysis of fusion offset in splicing photonic crystal fiber with CO2 laser

NASA Astrophysics Data System (ADS)

Jin, Wa; Bi, Weihong; Fu, Guangwei

2014-09-01

Single mode fibers (SMFs) need more fusion energy than PCFs during a splicing process, and it is necessary to make some offsets of the center of heat source toward to the SMFs. Based on the study of characteristics of heat transfer of PCFs and SMFs during splicing process with CO2 laser as the heat source, this paper reports the first systematic analysis of the optimal splicing offset of splicing SMFs and PCFs in theory and experiments. The results show that fusion splicing offsets can be applied to control the air-hole collapse and realize the practical splicing process between PCFs and SMFs with low loss.

Improved silicon nitride for advanced heat engines

NASA Technical Reports Server (NTRS)

Yeh, H. C.; Wimmer, J. M.

1986-01-01

Silicon nitride is a high temperature material currently under consideration for heat engine and other applications. The objective is to improve the net shape fabrication technology of Si3N4 by injection molding. This is to be accomplished by optimizing the process through a series of statistically designed matrix experiments. To provide input to the matrix experiments, a wide range of alternate materials and processing parameters was investigated throughout the whole program. The improvement in the processing is to be demonstrated by a 20 percent increase in strength and a 100 percent increase in the Weibull modulus over that of the baseline material. A full characterization of the baseline process was completed. Material properties were found to be highly dependent on each step of the process. Several important parameters identified thus far are the starting raw materials, sinter/hot isostatic pressing cycle, powder bed, mixing methods, and sintering aid levels.

Chemistry Notes.

ERIC Educational Resources Information Center

School Science Review, 1983

1983-01-01

Presents chemistry experiments, laboratory procedures, demonstrations, and classroom materials/activities. These include: experiments on colloids, processing of uranium ore, action of heat on carbonates; color test for phenols and aromatic amines; solvent properties of non-electrolytes; stereoscopic applications/methods; a valency balance;…

Helium refrigeration system for hydrogen liquefaction applications

NASA Astrophysics Data System (ADS)

Nair, J. Kumar, Sr.; Menon, RS; Goyal, M.; Ansari, NA; Chakravarty, A.; Joemon, V.

2017-02-01

Liquid hydrogen around 20 K is used as cold moderator for generating “cold neutron beam” in nuclear research reactors. A cryogenic helium refrigeration system is the core upon which such hydrogen liquefaction applications are built. A thermodynamic process based on reversed Brayton cycle with two stage expansion using high speed cryogenic turboexpanders (TEX) along with a pair of compact high effectiveness process heat exchangers (HX), is well suited for such applications. An existing helium refrigeration system, which had earlier demonstrated a refrigeration capacity of 470 W at around 20 K, is modified based on past operational experiences and newer application requirements. Modifications include addition of a new heat exchanger to simulate cryogenic process load and two other heat exchangers for controlling the temperatures of helium streams leading out to the application system. To incorporate these changes, cryogenic piping inside the cold box is suitably modified. This paper presents process simulation, sizing of new heat exchangers as well as fabrication aspects of the modified cryogenic process piping.

Testing a Constrained MPC Controller in a Process Control Laboratory

ERIC Educational Resources Information Center

Ricardez-Sandoval, Luis A.; Blankespoor, Wesley; Budman, Hector M.

2010-01-01

This paper describes an experiment performed by the fourth year chemical engineering students in the process control laboratory at the University of Waterloo. The objective of this experiment is to test the capabilities of a constrained Model Predictive Controller (MPC) to control the operation of a Double Pipe Heat Exchanger (DPHE) in real time.…

Space processing applications payload equipment study. Volume 2D: SPA supplemental power and heat rejection kit

NASA Technical Reports Server (NTRS)

Hammel, R. L. (Editor); Smith, A. G. (Editor)

1974-01-01

The design and application of a supplementary power and heat rejection kit for the Spacelab are discussed. Two subsystems of electric power and thermal control were analyzed to define the requirements for the power and heat rejection kit (PHRK). Twelve exemplary experiments were defined and power timelines were developed. From these timeline, the experiment requirements for sustained power, peak power, and energy were determined. The electrical power subsystem of the PHRK will consist of two fuel cells, oxygen and hydrogen reactant tank assemblies, water storage tanks, plumbing, cabling, and inverters to convert the nominal 28 volt dc fuel cell output to ac power.

Smouldering (thermal) remediation of soil contaminated with industrial organic liquids: novel insights into heat transfer and kinetics uncovered by integrating experiments and modelling

NASA Astrophysics Data System (ADS)

Gerhard, J.; Zanoni, M. A. B.; Torero, J. L.

2017-12-01

Smouldering (i.e., flameless combustion) underpins the technology Self-sustaining Treatment for Active Remediation (STAR). STAR achieves the in situ destruction of nonaqueous phase liquids (NAPLs) by generating a self-sustained smouldering reaction that propagates through the source zone. This research explores the nature of the travelling reaction and the influence of key in situ and engineered characteristics. A novel one-dimensional numerical model was developed (in COMSOL) to simulate the smouldering remediation of bitumen-contaminated sand. This model was validated against laboratory column experiments. Achieving model validation depended on correctly simulating the energy balance at the reaction front, including properly accounting for heat transfer, smouldering kinetics, and heat losses. Heat transfer between soil and air was demonstrated to be generally not at equilibrium. Moreover, existing heat transfer correlations were found to be inappropriate for the low air flow Reynold's numbers (Re < 30) relevant in this and similar thermal remediation systems. Therefore, a suite of experiments were conducted to generate a new heat transfer correlation, which generated correct simulations of convective heat flow through soil. Moreover, it was found that, for most cases of interest, a simple two-step pyrolysis/oxidation set of kinetic reactions was sufficient. Arrhenius parameters, calculated independently from thermogravimetric experiments, allowed the reaction kinetics to be validated in the smouldering model. Furthermore, a simple heat loss term sufficiently accounted for radial heat losses from the column. Altogether, these advances allow this simple model to reasonably predict the self-sustaining process including the peak reaction temperature, the reaction velocity, and the complete destruction of bitumen behind the front. Simulations with the validated model revealed numerous unique insights, including how the system inherently recycles energy, how air flow rate and NAPL saturation dictate contaminant destruction rates, and the extremes that lead to extinction. Overall, this research provides unique insights into the complex interplay of thermochemical processes that govern the success of smouldering as well as other thermal remediation approaches.

The Law of Entropy Increase - A Lab Experiment

NASA Astrophysics Data System (ADS)

Dittrich, William; Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

2016-09-01

The second law of thermodynamics has various formulations. There is the "Clausius formulation," which can be stated in a very intuitive way: "No process is possible whose sole result is the transfer of heat from a cooler to a hotter body." There is also the "Kelvin-Plank principle," which states that "no cyclic process exists whose sole result is the absorption of heat from a reservoir and the conversion of all this heat into work" [emphasis added] (since this would require perfect energy conversion efficiency). Both these statements can be presented to physics students in a conceptual manner, and students' "everyday" experiences will support either statement of the second law of thermodynamics. However, when the second law of thermodynamics is expressed using the concept of entropy (ΔS ≥ 0, for a closed system), most first-year physics students lack any direct experimental experience with this parameter. This paper describes a calculation of the increase in entropy that can be performed while completing three traditional thermodynamics experiments. These simple and quick calculations help students become familiar and comfortable with the concept of entropy. This paper is complementary to prior work where classroom activities were developed to provide insight into the statistical nature of entropy.

Convection measurement package for space processing sounding rocket flights. [low gravity manufacturing - fluid dynamics

NASA Technical Reports Server (NTRS)

Spradley, L. W.

1975-01-01

The effects on heated fluids of nonconstant accelerations, rocket vibrations, and spin rates, was studied. A system is discussed which can determine the influence of the convective effects on fluid experiments. The general suitability of sounding rockets for performing these experiments is treated. An analytical investigation of convection in an enclosure which is heated in low gravity is examined. The gravitational body force was taken as a time-varying function using anticipated sounding rocket accelerations, since accelerometer flight data were not available. A computer program was used to calculate the flow rates and heat transfer in fluids with geometries and boundary conditions typical of space processing configurations. Results of the analytical investigation identify the configurations, fluids and boundary values which are most suitable for measuring the convective environment of sounding rockets. A short description of fabricated fluid cells and the convection measurement package is given. Photographs are included.

Experiments in Transitional Boundary Layers With Emphasis on High Free-Stream Disturbance Level, Surface Concave Curvature and Strong Favorable Streamwise Pressure Gradient Effects

NASA Technical Reports Server (NTRS)

Simon, T. W.; Volino, R. J.

2007-01-01

Experiments on boundary layer transition with flat, concave and convex walls and various levels of free-stream disturbance and with zero and strong streamwise acceleration have been conducted. Measurements of both fluid mechanics and heat transfer processes were taken. Examples are profiles of mean velocity and temperature; Reynolds normal and shear stresses; turbulent streamwise and cross-stream heat fluxed; turbulent Prandtl number; and streamwise variations of wall skin friction and heat transfer coefficient values. Free-stream turbulence levels were varied over the range from about 0.3 percent to about 8 percent. The effects of curvature on the onset of transition under low disturbance conditions are clear; concave curvature leads to an earlier and more rapid transition and the opposite is true for convex curvature This was previously known but little documentation of the transport processes in the flow was available

Unit Operation Experiment Linking Classroom with Industrial Processing

ERIC Educational Resources Information Center

Benson, Tracy J.; Richmond, Peyton C.; LeBlanc, Weldon

2013-01-01

An industrial-type distillation column, including appropriate pumps, heat exchangers, and automation, was used as a unit operations experiment to provide a link between classroom teaching and real-world applications. Students were presented with an open-ended experiment where they defined the testing parameters to solve a generalized problem. The…

Centrifugal Gas Compression Cycle

NASA Astrophysics Data System (ADS)

Fultun, Roy

2002-11-01

A centrifuged gas of kinetic, elastic hard spheres compresses isothermally and without flow of heat in a process that reverses free expansion. This theorem follows from stated assumptions via a collection of thought experiments, theorems and other supporting results, and it excludes application of the reversible mechanical adiabatic power law in this context. The existence of an isothermal adiabatic centrifugal compression process makes a three-process cycle possible using a fixed sample of the working gas. The three processes are: adiabatic mechanical expansion and cooling against a piston, isothermal adiabatic centrifugal compression back to the original volume, and isochoric temperature rise back to the original temperature due to an influx of heat. This cycle forms the basis for a Thomson perpetuum mobile that induces a loop of energy flow in an isolated system consisting of a heat bath connectable by a thermal path to the working gas, a mechanical extractor of the gas's internal energy, and a device that uses that mechanical energy and dissipates it as heat back into the heat bath. We present a simple experimental procedure to test the assertion that adiabatic centrifugal compression is isothermal. An energy budget for the cycle provides a criterion for breakeven in the conversion of heat to mechanical energy.

Optical Properties and Microstructure of Barium Titanate Thin Film (BaTiO3) for Solar Cell Applications

NASA Astrophysics Data System (ADS)

Setyadi, A. U. L. S.; Iriani, Y.; Nurosyid, F.

2018-03-01

Barium Titanate thin films were prepared with variations in the number of layers and variation of the solution on a Quartz substrate using the sol-gel method with spin coating technique, at rotation speed 3000 rpm for 30 seconds. The first solution was made with heated and the second with stirred and heated. In this experiment, BaTiO3 were heated at 900°C for 2 hours. The characterization of optical properties was performed by UV-Vis spectrometer and microstructural characterization was performed by X-Ray Diffraction (XRD). Variation of layers number affects the intensity of the diffraction peaks. The more layers of the intensity are also greater. The variation of solution making process affects the intensity of diffraction peak. The process of making the solution with stirred and heated has greater intensity than the process of solution by simply heating it. When stirred at the same time heated to produce atoms diffuses more easily with other atoms so the bonds between atoms are more orderly and strong. The process of making the solution in the heated is larger in the crystallite size of than preparation of solution by stirred and heated. The stirred which the solution is produced influences the appearance of the size of the crystal. Variation number of layers influences the absorbance value of layer. The absorbance increases with increasing number of layers. The absorbance of the sample was made with heated the higher than with stirred and heated.

Viking heat sterilization - Progress and problems

NASA Technical Reports Server (NTRS)

Daspit, L. P.; Cortright, E. M.; Stern, J. A.

1974-01-01

The Viking Mars landers to be launched in 1975 will carry experiments in biology, planetology, and atmospheric physics. A terminal dry-heat sterilization process using an inert gas was chosen to meet planetary quarantine requirements and preclude contamination of the biology experiment by terrestrial organisms. Deep sterilization is performed at the component level and terminal surface sterilization at the system level. Solutions to certain component problems relating to sterilization are discussed, involving the gyroscope, tape recorder, battery, electronic circuitry, and outgassing. Heat treatment placed special requirements on electronic packaging, including fastener preload monitoring and solder joints. Chemical and physical testing of nonmetallic materials was performed to establish data on their behavior in heat-treatment and vacuum environments. A Thermal Effects Test Model and a Proof Test Capsule were used. It is concluded that a space vehicle can be designed and fabricated to withstand heat sterilization requirements.

Qualitative analysis of Pb liquid sample using laser-induced breakdown spectroscopy (LIBS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suyanto, Hery; Rupiasih, Ni Nyoman; Winardi, T. B.

2013-09-03

Qualitative analysis of liquid sample containing 1,000 ppm of Pb was performed by using LIBS technique. In order to avoid splashing off of the liquid sample during laser irradiation, a sample pretreatment was done, namely the liquid sample was absorbed by using commercial available stomach medicine. Two kinds of absorbent materials were chosen in this experiment, first containing 125 mg activated carbon and second 600 mg activated attapulgite. These absorbent materials were used since carbon sample gives better absorption of infrared laser irradiation used in this experiment. In order to characterize the absorption process, three treatments were conducted in thismore » experiment; first, without heating the sample but varying the absorption time before laser irradiation; second by varying the heating temperature after certain time of absorption process and third by varying the temperature only. The maximum emission intensity of Pb I 405.7 nm was found in the second treatment of heating the sample till 85°C after 30 minutes absorption of the liquid sample in both absorbent materials.« less

Transient experiments with thermite melts for a core catcher concept based on water addition from below

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tromm, W.; Alsmeyer, H.

1995-09-01

A core catcher concept is proposed to be integrated into a new pressurized water reactor. The core catcher achieves coolability by spreading and fragmentation of the ex-vessel core melt based on a process of water inlet from the bottom through the melt. By highly effective heat removal that uses evaporating water in direct contact with the fragmented melt, the corium melt would solidify in a short time period, and long-term cooling could be maintained by continuous water evaporation from the flooded porous or fragmented corium bed. The key process for obtaining coolability is the coupling of the three effects: (a)more » water ingression from below and its evaporation, (b) break up and fragmentation of the corium layer, and (c) heat transfer and solidification of the let. These mechanisms are investigated in transient medium-scale experiments with thermite melts. The experimental setup represents a section of the proposed core catcher design. A thermite melt is located on the core catcher plate with a passive water supply from the bottom. After generation of the melt, the upper sacrificial layer is eroded until water penetrates into the melt for the bottom through plugs in the supporting plate. Fragmentation and fast solidification of the melt are observed, and long-term heat removal is guaranteed by the coolant water flooding the porous melt. Water inflow is sufficient to safely remove the decay heat in a comparable corium layer. The open porosity is created by the vapor streaming through the melt during the solidification process. Fracture of the solid by thermomechanical stresses is not observed. The experiments in their current stage show the principal feasibility of the proposed cooling concept and are used to prepare large-scale experiments to be performed in the modified BETA facility with sustained heating of the melt.« less

Formation of Azaspiracids-3, -4, -6, and -9 via decarboxylation of carboxyazaspiracid metabolites from shellfish.

PubMed

McCarron, Pearse; Kilcoyne, Jane; Miles, Christopher O; Hess, Philipp

2009-01-14

The azaspiracid (AZA) class of phycotoxins has been responsible for extended closures of shellfisheries in various locations around Europe, where levels of AZA1-3 are regulated in shellfish. Since their discovery in 1995, AZAs have been the focus of much research, resulting in the discovery of numerous analogues. During studies of procedures for processing of AZA-contaminated mussels ( Mytilus edulis ), an unusual phenomenon was observed involving AZA3. In uncooked tissues, AZA3 levels would increase significantly when heated for short periods of time in the absence of water loss. A similar increase in AZA3 concentrations occurred during storage of shellfish tissue reference materials for several months at temperatures as low as 4 degrees C. Concentrations of AZA1 and AZA2 did not change during these experiments. Several possible explanations were investigated, including an AZA3-specific matrix effect upon heating of tissues, release of AZA3 from the matrix, and formation of AZA3 from a precursor. Preliminary experiments indicated that toxin conversion was responsible, and more detailed studies focused on this possibility. LC-MS analysis of heating trials, deuterium labeling experiments, and kinetic studies demonstrated that a carboxylated AZA analogue, AZA17, undergoes rapid decarboxylation when heated to produce AZA3. Heat-induced decarboxylation of AZA19, AZA21, and AZA23 to form AZA6, AZA4, and AZA9, respectively, was also demonstrated. This finding is of great significance in terms of procedures used in the processing of shellfish for regulatory analysis, and it exemplifies the role that chemical analysis can play in understanding the contribution of metabolic processes to the toxin profiles observed in shellfish samples.

Detection of Heating Processes in Coronal Loops by Soft X-ray Spectroscopy

NASA Astrophysics Data System (ADS)

Kawate, Tomoko; Narukage, Noriyuki; Ishikawa, Shin-nosuke; Imada, Shinsuke

2017-08-01

Imaging and Spectroscopic observations in the soft X-ray band will open a new window of the heating/acceleration/transport processes in the solar corona. The soft X-ray spectrum between 0.5 and 10 keV consists of the electron thermal free-free continuum and hot coronal lines such as O VIII, Fe XVII, Mg XI, Si XVII. Intensity of free-free continuum emission is not affected by the population of ions, whereas line intensities especially from highly ionized species have a sensitivity of the timescale of ionization/recombination processes. Thus, spectroscopic observations of both continuum and line intensities have a capability of diagnostics of heating/cooling timescales. We perform a 1D hydrodynamic simulation coupled with the time-dependent ionization, and calculate continuum and line intensities under different heat input conditions in a coronal loop. We also examine the differential emission measure of the coronal loop from the time-integrated soft x-ray spectra. As a result, line intensity shows a departure from the ionization equilibrium and shows different responses depending on the frequency of the heat input. Solar soft X-ray spectroscopic imager will be mounted in the sounding rocket experiment of the Focusing Optics X-ray Solar Imager (FOXSI). This observation will deepen our understanding of heating processes to solve the “coronal heating problem”.

A study of the impact of moist-heat and dry-heat treatment processes on hazardous trace elements migration in food waste.

PubMed

Chen, Ting; Jin, Yiying; Qiu, Xiaopeng; Chen, Xin

2015-03-01

Using laboratory experiments, the authors investigated the impact of dry-heat and moist-heat treatment processes on hazardous trace elements (As, Hg, Cd, Cr, and Pb) in food waste and explored their distribution patterns for three waste components: oil, aqueous, and solid components. The results indicated that an insignificant reduction of hazardous trace elements in heat-treated waste-0.61-14.29% after moist-heat treatment and 4.53-12.25% after dry-heat treatment-and a significant reduction in hazardous trace elements (except for Hg without external addition) after centrifugal dehydration (P < 0.5). Moreover, after heat treatment, over 90% of the hazardous trace elements in the waste were detected in the aqueous and solid components, whereas only a trace amount of hazardous trace elements was detected in the oil component (<0.01%). In addition, results indicated that heat treatment process did not significantly reduce the concentration of hazardous trace elements in food waste, but the separation process for solid and aqueous components, such as centrifugal dehydration, could reduce the risk considerably. Finally, combined with the separation technology for solid and liquid components, dry-heat treatment is superior to moist-heat treatment on the removal of external water-soluble ionic hazardous trace elements. An insignificant reduction of hazardous trace elements in heat-treated waste showed that heat treatment does not reduce trace elements contamination in food waste considerably, whereas the separation process for solid and aqueous components, such as centrifugal dehydration, could reduce the risk significantly. Moreover, combined with the separation technology for solid and liquid components, dry-heat treatment is superior to moist-heat treatment for the removal of external water-soluble ionic hazardous trace elements, by exploring distribution patterns of trace elements in three waste components: oil, aqueous, and solid components.

Heat-Assisted Machining for Material Removal Improvement

NASA Astrophysics Data System (ADS)

Mohd Hadzley, A. B.; Hafiz, S. Muhammad; Azahar, W.; Izamshah, R.; Mohd Shahir, K.; Abu, A.

2015-09-01

Heat assisted machining (HAM) is a process where an intense heat source is used to locally soften the workpiece material before machined by high speed cutting tool. In this paper, an HAM machine is developed by modification of small CNC machine with the addition of special jig to hold the heat sources in front of the machine spindle. Preliminary experiment to evaluate the capability of HAM machine to produce groove formation for slotting process was conducted. A block AISI D2 tool steel with100mm (width) × 100mm (length) × 20mm (height) size has been cut by plasma heating with different setting of arc current, feed rate and air pressure. Their effect has been analyzed based on distance of cut (DOC).Experimental results demonstrated the most significant factor that contributed to the DOC is arc current, followed by the feed rate and air pressure. HAM improves the slotting process of AISI D2 by increasing distance of cut due to initial cutting groove that formed during thermal melting and pressurized air from the heat source.

Ion Cyclotron Waves in the VASIMR

NASA Astrophysics Data System (ADS)

Brukardt, M. S.; Bering, E. A.; Chang-Diaz, F. R.; Squire, J. P.; Longmier, B.

2008-12-01

The Variable Specific Impulse Magnetoplasma Rocket is an electric propulsion system under development at Ad Astra Rocket Company that utilizes several processes of ion acceleration and heating that occur in the Birkeland currents of an auroral arc system. Among these processes are parallel electric field acceleration, lower hybrid resonance heating, and ion cyclotron resonance heating. The VASIMR is capable of laboratory simulation of electromagnetic ion cyclotron wave heating during a single pass of the plasma through the resonance region. The plasma is generated by a helicon discharge of about 25 kW then passes through an RF booster stage that shoots left hand polarized slow mode waves from the high field side of the resonance. This paper will focus on the upgrades to the VX-200 test model over the last year. After summarizing the VX- 50 and VX-100 results, the new data from the VX-200 model will be presented. Lastly, the changes to the VASIMR experiment due to Ad Astra Rocket Company's new facility in Webster, Texas will also be discussed, including the possibility of collaborative experiments at the new facility.

[MSW incineration fly ash melting by DSC-DTA].

PubMed

Li, Rundong; Chi, Yong; Li, Shuiqing; Wang, Lei; Yan, Jianhua; Cen, Kefa

2002-07-01

Melting characteristics of two kinds of municipal solid waste incineration(MSWI) fly ash were studied in this paper by high temperature differential scanning calorimetry and differential temperature analysis. MSWI fly ash was considered as hazardous waste because it contains heavy metals and dioxins. The experiments were performed in either N2 or O2 atmosphere in temperature range of 20 degrees C-1450 degrees C at various heating rates. Two different MSW incineration fly ashes used in the experiments were collected from our country and France respectively. The process of fly ash melting exhibits two reactions occurring at temperature ranges of about 480 degrees C-670 degrees C and 1136 degrees C-1231 degrees C, respectively. The latent heat of polymorphic transformation and fusion were approximately 20 kJ/kg and 700 kJ/kg, while the total heat required for melting process was about 1800 kJ/kg. The paper also studied effect of CaO to melting. A heat flux thermodynamic model for fly ash melting was put forward and it agrees well with experimental data.

Electromagnetic containerless processing requirements and recommended facility concept and capabilities for space lab

NASA Technical Reports Server (NTRS)

Frost, R. T.; Bloom, H. L.; Napaluch, L. J.; Stockhoff, E. H.; Wouch, G.

1974-01-01

Containerless melting, reaction, and solidification experiments and processes which potentially can lead to new understanding of material science and production of new or improved materials in the weightless space environment are reviewed in terms of planning for spacelab. Most of the experiments and processes discussed are amenable to the employment of electromagnetic position control and electromagnetic induction or electron beam heating and melting. The spectrum of relevant properties of materials, which determine requirements for a space laboratory electromagnetic containerless processing facility are reviewed. Appropriate distributions and associated coil structures are analyzed and compared on the basis of efficiency, for providing the functions of position sensing, control, and induction heating. Several coil systems are found capable of providing these functions. Exchangeable modular coils in appropriate sizes are recommended to achieve the maximum power efficiencies, for a wide range of specimen sizes and resistivities, in order to conserve total facility power.

Experimental and numerical investigation of one and two phase natural convection in storage tanks

NASA Astrophysics Data System (ADS)

Aszodi, A.; Krepper, E.; Prasser, H.-M.

Experiments were performed to investigate heating up processes of fluids in storage tanks under the influence of an external heat source. As a consequence of an external fire, the heat-up of the inventory may lead to the evaporation of the liquid and to release of significant quantities of dangerous gases into the environment. Several tests were performed both with heating from the bottom and with heating from the side walls. In recent tests in addition to thermocouples, the tank was equipped with needle probes for measuring of the local void fraction. The paper presents experimental and numerical investigations of single and two phase heating up processes of tanks with side wall heating. The measurement of the temperature and of the void fraction makes interesting phenomena evident, which could be explained by an own 2D model. The gained experimental results may be used for the validation of boiling models in 3D CFD codes.

Whole body heat stress increases motor cortical excitability and skill acquisition in humans.

PubMed

Littmann, Andrew E; Shields, Richard K

2016-02-01

Vigorous systemic exercise stimulates a cascade of molecular and cellular processes that enhance central nervous system (CNS) plasticity and performance. The influence of heat stress on CNS performance and learning is novel. We designed two experiments to determine whether passive heat stress (1) facilitated motor cortex excitability and (2) improved motor task acquisition compared to no heat stress. Motor evoked potentials (MEPs) from the first dorsal interosseus (FDI) were collected before and after 30 min of heat stress at 73 °C. A second cohort of subjects performed a motor learning task using the FDI either following heat or the no heat condition. Heat stress increased heart rate to 65% of age-predicted maximum. After heat, mean resting MEP amplitude increased 48% (p<0.05). MEP stimulus-response amplitudes did not differ according to stimulus intensity. In the second experiment, heat stress caused a significant decrease in absolute and variable error (p<0.05) during a novel movement task using the FDI. Passive environmental heat stress (1) increases motor cortical excitability, and (2) enhances performance in a motor skill acquisition task. Controlled heat stress may prime the CNS to enhance motor skill acquisition during rehabilitation. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Coupling heat and chemical tracer experiments for estimating heat transfer parameters in shallow alluvial aquifers.

PubMed

Wildemeersch, S; Jamin, P; Orban, P; Hermans, T; Klepikova, M; Nguyen, F; Brouyère, S; Dassargues, A

2014-11-15

Geothermal energy systems, closed or open, are increasingly considered for heating and/or cooling buildings. The efficiency of such systems depends on the thermal properties of the subsurface. Therefore, feasibility and impact studies performed prior to their installation should include a field characterization of thermal properties and a heat transfer model using parameter values measured in situ. However, there is a lack of in situ experiments and methodology for performing such a field characterization, especially for open systems. This study presents an in situ experiment designed for estimating heat transfer parameters in shallow alluvial aquifers with focus on the specific heat capacity. This experiment consists in simultaneously injecting hot water and a chemical tracer into the aquifer and monitoring the evolution of groundwater temperature and concentration in the recovery well (and possibly in other piezometers located down gradient). Temperature and concentrations are then used for estimating the specific heat capacity. The first method for estimating this parameter is based on a modeling in series of the chemical tracer and temperature breakthrough curves at the recovery well. The second method is based on an energy balance. The values of specific heat capacity estimated for both methods (2.30 and 2.54MJ/m(3)/K) for the experimental site in the alluvial aquifer of the Meuse River (Belgium) are almost identical and consistent with values found in the literature. Temperature breakthrough curves in other piezometers are not required for estimating the specific heat capacity. However, they highlight that heat transfer in the alluvial aquifer of the Meuse River is complex and contrasted with different dominant process depending on the depth leading to significant vertical heat exchange between upper and lower part of the aquifer. Furthermore, these temperature breakthrough curves could be included in the calibration of a complex heat transfer model for estimating the entire set of heat transfer parameters and their spatial distribution by inverse modeling. Copyright © 2014 Elsevier B.V. All rights reserved.

Harnessing the Sun for development: Actions for consideration by the international community at the UN Conference on New and Renewable Sources of Energy for promoting the use of renewable energy in developing countries

NASA Astrophysics Data System (ADS)

Jhirad, D. J.; Mubayi, V.; Weingart, J.

1981-08-01

The technical and economic evidence is reviewed for solar industrial process heat, highlighting the fact that financial parameters such as tax credits and depreciation allowance play a very large role in determining the economic competitiveness of solar investments. An analysis of the energy (and oil) consumed in providing industrial process heat in a number of selected developing countries is presented. Solar industrial process heat technology is discussed including the operating experience of several demonstration plants in the US Solar ponds are also described briefly. A financial and economic analysis of solar industrial process heat systems under different assumptions on future oil prices and various financial parameters is given. Financial analyses are summarized for a solar industrial process heat retrofit of a brewery in Zimbabwe and a high efficiency system operating in financial conditions typical of the US and a number of other industrialized nations. A set of recommended policy actions for countries wishing to enhance the commercial feasibility of renewable energy technologies in the commercial and industrial sections is presented.

One-dimensional thermohydraulic code THESEUS and its application to chilldown process simulation in two-phase hydrogen flows

NASA Astrophysics Data System (ADS)

Papadimitriou, P.; Skorek, T.

THESUS is a thermohydraulic code for the calculation of steady state and transient processes of two-phase cryogenic flows. The physical model is based on four conservation equations with separate liquid and gas phase mass conservation equations. The thermohydraulic non-equilibrium is calculated by means of evaporation and condensation models. The mechanical non-equilibrium is modeled by a full-range drift-flux model. Also heat conduction in solid structures and heat exchange for the full spectrum of heat transfer regimes can be simulated. Test analyses of two-channel chilldown experiments and comparisons with the measured data have been performed.

Thermal Inactivation of Feline Calicivirus in Pet Food Processing.

PubMed

Haines, J; Patel, M; Knight, A I; Corley, D; Gibson, G; Schaaf, J; Moulin, J; Zuber, S

2015-12-01

Extrusion is the most common manufacturing process used to produce heat-treated dry dog and cat food (pet food) for domestic use and international trade. Due to reoccurring outbreaks of notifiable terrestrial animal diseases and their impact on international trade, experiments were undertaken to demonstrate the effectiveness of heat-treated extruded pet food on virus inactivation. The impact of extrusion processing in a pet food matrix on virus inactivation has not been previously reported and very few inactivation studies have examined the thermal inactivation of viruses in complex food matrices. The feline calicivirus vaccine strain FCV F-9 was used as a surrogate model RNA virus pathogen. Small-scale heat inactivation experiments using animal-derived pet food raw materials showed that a > 4 log10 reduction (log10 R) in infectivity occurred at 70 °C prior to reaching the minimum extrusion manufacturing operating temperature of 100 °C. As anticipated, small-scale pressure studies at extrusion pressure (1.6 MPa) showed no apparent effect on FCV F-9 inactivation. Additionally, FCV F-9 was shown not to survive the acidic conditions used to produce pet food palatants of animal origin that are typically used as a coating after the extrusion process.

A multi-step reaction model for ignition of fully-dense Al-CuO nanocomposite powders

NASA Astrophysics Data System (ADS)

Stamatis, D.; Ermoline, A.; Dreizin, E. L.

2012-12-01

A multi-step reaction model is developed to describe heterogeneous processes occurring upon heating of an Al-CuO nanocomposite material prepared by arrested reactive milling. The reaction model couples a previously derived Cabrera-Mott oxidation mechanism describing initial, low temperature processes and an aluminium oxidation model including formation of different alumina polymorphs at increased film thicknesses and higher temperatures. The reaction model is tuned using traces measured by differential scanning calorimetry. Ignition is studied for thin powder layers and individual particles using respectively the heated filament (heating rates of 103-104 K s-1) and laser ignition (heating rate ∼106 K s-1) experiments. The developed heterogeneous reaction model predicts a sharp temperature increase, which can be associated with ignition when the laser power approaches the experimental ignition threshold. In experiments, particles ignited by the laser beam are observed to explode, indicating a substantial gas release accompanying ignition. For the heated filament experiments, the model predicts exothermic reactions at the temperatures, at which ignition is observed experimentally; however, strong thermal contact between the metal filament and powder prevents the model from predicting the thermal runaway. It is suggested that oxygen gas release from decomposing CuO, as observed from particles exploding upon ignition in the laser beam, disrupts the thermal contact of the powder and filament; this phenomenon must be included in the filament ignition model to enable prediction of the temperature runaway.

Experimental investigation on phase change materials as heating element for non-electric neonatal incubator

NASA Astrophysics Data System (ADS)

Matahari, Rho Natta; Putra, Nandy; Ariantara, Bambang; Amin, Muhammad; Prawiro, Erwin

2017-02-01

High number of preterm births is one of the issues in improving health standard. The effort to help premature babies is hampered by high cost of NICU care in hospital. In addition, uneven distribution of electricity to remote area made it hard to operate the incubator. Utilization of phase change material beeswax to non-electricity incubator as heating element becomes alternative option to save premature babies. The objective of this experiment is to investigate the most efficient mass of beeswax according to Indonesian National Standard to earn over time and ideal temperature of incubator. Experiment was performed using prototype incubator, which utilizes natural convection phenomenon in the heating process of incubator. Utilization of fin is to accelerate heat distribution in the incubator. Result of experiment showed that the most efficient mass of PCM is 3 kg, which has 2.45 hours of running time for maintaining temperature of incubator in range of 32-36 °C.

Marangoni Effects on Near-Bubble Microscale Transport During Boiling of Binary Fluid Mixtures

NASA Technical Reports Server (NTRS)

V. Carey; Sun, C.; Carey, V. P.

2000-01-01

In earlier investigations, Marangoni effects were observed to be the dominant mechanism of boiling transport in 2-propanol/water mixtures under reduced gravity conditions. In this investigation we have examined the mechanisms of binary mixture boiling by exploring the transport near a single bubble generated in a binary mixture between a heated surface and cold surface. The temperature field created in the liquid around the bubble produces vaporization over the portion of its interface near the heated surface and condensation over portions of its interface near the cold surface. Experiments were conducted using different mixtures of water and 2-propanol under 1g conditions and under reduced gravity conditions aboard the KC135 aircraft. Since 2-propanol is more volatile than water, there is a lower concentration of 2-propanol near the hot surface and a higher concentration of 2-propanol near the cold plate relative to the bulk quantity. This difference in interface concentration gives rise to strong Marangoni effects that move liquid toward the hot plate in the near bubble region for 2-propanol and water mixtures. In the experiments in this study, the pressure of the test system was maintained at about 5 kPa to achieve the full spectrum of boiling behavior (nucleate boiling, critical heat flux and film boiling) at low temperature and heat flux levels. Heat transfer data and visual documentation of the bubble shape were extracted from the experimental results. In the 1-g experiments at moderate to high heat flux levels, the bubble was observed to grow into a mushroom shape with a larger top portion near the cold plate due to the buoyancy effect. The shape of the bubble was somewhat affected by the cold plate subcooling and the superheat of the heated surface. At low superheat levels for the heated surface, several active nucleation sites were observed, and the vapor stems from them merged to form a larger bubble. The generation rate of vapor is moderate in this regime and the bubble shape is cylindrical in appearance. In some instances, the bubble interface appeared to oscillate. At higher applied heat flux levels, the top of the bubble became larger, apparently to provide more condensing interface area adjacent to the cold plate. Increasing the applied heat flux ultimately led to dry-out of the heated surface, with conditions just prior to dryout corresponding to the maximum heat flux (CHF). A more stable bubble was observed when the system attained the minimum heat flux (for film boiling). In this regime, most of the surface under the bottom of the bubble was dry with nucleate boiling sometimes occuring around the contact perimeter of the bubble at heated surface. Different variations (e.g. gap between two plates, molar concentration of the liquid mixture) of the experiments were examined to determine parametric effects on the boiling process and to determine the best conditions for the KC135 reduced gravity tests. Variation of the gap was found to have a minor impact on the CHF. However, reducing the gap between the hot and cold surface was observed to significantly reduce the minimum heat flux for fixed molar concentration of 2-propanol. In the reduced gravity experiments aboard the KC135 aircraft, the bubble formed in the 6.4 mm gap was generally cylindrical or barrel shaped and it increased its extent laterally as the surface superheat increased. In reduced gravity experiments, dryout of the heated surface under the bubble was observed to occur at a lower superheated temperature than for 1g conditions. Observed features of the boiling process and heat transfer data under reduced gravity will be discussed in detail. The results of the reduced gravity experiments will also be compared to those obtained in comparable 1g experiments. In tandem with the experiments we are also developing a computational model of the transport in the liquid surrounding the bubble during the boiling process. The computational model uses a level set method to model motion of the interface. It will incorporate a macroscale treatment of the transport in the liquid gap between the surfaces and a microscale treatment of transport in the regions between the bubble interface and the solid surfaces. The features of the model will be described in detail. Future research directions suggested by the results to date will also be discussed.

Simulation of the planetary interior differentiation processes in the laboratory.

PubMed

Fei, Yingwei

2013-11-15

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to that layered structure, (1) percolation of liquid metal in a solid silicate matrix by planet differentiation, and (2) inner core crystallization by subsequent planet cooling. We conduct high-pressure and high-temperature experiments to simulate both processes in the laboratory. Formation of percolative planetary core depends on the efficiency of melt percolation, which is controlled by the dihedral (wetting) angle. The percolation simulation includes heating the sample at high pressure to a target temperature at which iron-sulfur alloy is molten while the silicate remains solid, and then determining the true dihedral angle to evaluate the style of liquid migration in a crystalline matrix by 3D visualization. The 3D volume rendering is achieved by slicing the recovered sample with a focused ion beam (FIB) and taking SEM image of each slice with a FIB/SEM crossbeam instrument. The second set of experiments is designed to understand the inner core crystallization and element distribution between the liquid outer core and solid inner core by determining the melting temperature and element partitioning at high pressure. The melting experiments are conducted in the multi-anvil apparatus up to 27 GPa and extended to higher pressure in the diamond-anvil cell with laser-heating. We have developed techniques to recover small heated samples by precision FIB milling and obtain high-resolution images of the laser-heated spot that show melting texture at high pressure. By analyzing the chemical compositions of the coexisting liquid and solid phases, we precisely determine the liquidus curve, providing necessary data to understand the inner core crystallization process.

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

PubMed Central

Fei, Yingwei

2013-01-01

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to that layered structure, (1) percolation of liquid metal in a solid silicate matrix by planet differentiation, and (2) inner core crystallization by subsequent planet cooling. We conduct high-pressure and high-temperature experiments to simulate both processes in the laboratory. Formation of percolative planetary core depends on the efficiency of melt percolation, which is controlled by the dihedral (wetting) angle. The percolation simulation includes heating the sample at high pressure to a target temperature at which iron-sulfur alloy is molten while the silicate remains solid, and then determining the true dihedral angle to evaluate the style of liquid migration in a crystalline matrix by 3D visualization. The 3D volume rendering is achieved by slicing the recovered sample with a focused ion beam (FIB) and taking SEM image of each slice with a FIB/SEM crossbeam instrument. The second set of experiments is designed to understand the inner core crystallization and element distribution between the liquid outer core and solid inner core by determining the melting temperature and element partitioning at high pressure. The melting experiments are conducted in the multi-anvil apparatus up to 27 GPa and extended to higher pressure in the diamond-anvil cell with laser-heating. We have developed techniques to recover small heated samples by precision FIB milling and obtain high-resolution images of the laser-heated spot that show melting texture at high pressure. By analyzing the chemical compositions of the coexisting liquid and solid phases, we precisely determine the liquidus curve, providing necessary data to understand the inner core crystallization process. PMID:24326245

Low-Temperature Oxidation-Free Selective Laser Sintering of Cu Nanoparticle Paste on a Polymer Substrate for the Flexible Touch Panel Applications.

PubMed

Kwon, Jinhyeong; Cho, Hyunmin; Eom, Hyeonjin; Lee, Habeom; Suh, Young Duk; Moon, Hyunjin; Shin, Jaeho; Hong, Sukjoon; Ko, Seung Hwan

2016-05-11

Copper nanomaterials suffer from severe oxidation problem despite the huge cost effectiveness. The effect of two different processes for conventional tube furnace heating and selective laser sintering on copper nanoparticle paste is compared in the aspects of chemical, electrical and surface morphology. The thermal behavior of the copper thin films by furnace and laser is compared by SEM, XRD, FT-IR, and XPS analysis. The selective laser sintering process ensures low annealing temperature, fast processing speed with remarkable oxidation suppression even in air environment while conventional tube furnace heating experiences moderate oxidation even in Ar environment. Moreover, the laser-sintered copper nanoparticle thin film shows good electrical property and reduced oxidation than conventional thermal heating process. Consequently, the proposed selective laser sintering process can be compatible with plastic substrate for copper based flexible electronics applications.

Influence of heat transmission mode on heating rates and on the selection of patches for heating in a mediterranean lizard.

PubMed

Belliure, Josabel; Carrascal, Luis M

2002-01-01

Heliothermy (heat gain by radiation) has been given a prominent role in basking lizards. However, thigmothermy (heat gain by conduction) could be relevant for heating in small lizards. To ascertain the importance of the different heat transmission modes to the thermoregulatory processes, we conducted an experimental study where we analyzed the role of heat transmission modes on heating rates and on the selection of sites for heating in the Mediterranean lizard Acanthodactylus erythrurus (Lacertidae). The study was conducted under laboratory conditions, where two situations of different operative temperatures (38 degrees and 50 degrees C) were simulated in a terrarium. In a first experiment, individuals were allowed to heat up during 2 min at both temperatures and under both heat transmission modes. In a second experiment, individuals were allowed to select between patches differing in the main transmission mode, at both temperatures, to heat up. Experiences were conducted with live, nontethered lizards with a starting body temperature of 27 degrees C. Temperature had a significant effect on the heating rate, with heat gain per unit of time being faster at the higher operative temperature (50 degrees C). The effect of the mode of heat transmission on the heating rate was also significant: at 50 degrees C, heating rate was greater when the main heat transmission mode was conduction from the substrate (thigmothermy) than when heating was mainly due to heat gain by radiation (heliothermy); at 38 degrees C, heating rates did not significantly differ between transmission modes. At 38 degrees C, selection of the site for heating was not significantly different from that expected by chance. However, at 50 degrees C, the heating site offering the slowest heating rate (heliothermic patch) was selected. These results show that heating rates vary not only with environmental temperature but also with different predominant heat transmission modes. Lizards are able to identify and exploit this heterogeneity, selecting the source of heat gain (radiation) that minimizes the risk of overheating when temperature is high.

Alloy Development, Processing and Characterization of Devitrified Titanium Base Microcrystalline Alloys.

DTIC Science & Technology

1984-12-01

quench rates (10V 10V [/sec). Since the heat transport and temperature profile of Ti melt in the cold copper crucible are not well known, melting...experiments in a cold copper crucible by arc heating were conducted using Ti-6.3Si alloy. The temperature measurement at both the surface and the bottom of the...melt spinning compart- ment B, and ribbon processing chamber C. The pre-melted alloy ingot is . - " charged directly into a cold copper crucible while

Enhancement of Pool Boiling Heat Transfer and Control of Bubble Motion in Microgravity Using Electric Fields - BCOEL

NASA Technical Reports Server (NTRS)

Herman, Cila; Iacona, Estelle; Acquaviva, Tom; Coho, Bill; Grant, Nechelle; Nahra, Henry; Sankaran, Subramanian; Taylor, Al; Julian, Ed; Robinson, Dale;

Enhancement of Pool Boiling Heat Transfer and Control of Bubble Motion in Microgravity Using Electric Fields (BCOEL)

NASA Technical Reports Server (NTRS)

Herman, Cila; Iacona, Estelle; Acquaviva, Tom; Coho, Bill; Grant, Nechelle; Nahra, Henry; Taylor, Al; Julian, Ed; Robinson, Dale; VanZandt, Dave

2001-01-01

The BCOEL project focuses on improving pool boiling heat transfer and bubble control in microgravity by exposing the fluid to electric fields. The electric fields induce a body force that can replace gravity in the low gravity environment, and enhance bubble removal from the heated surface. A better understanding of microgravity effects on boiling with and without electric fields is critical to the proper design of the phase-change-heat-removal equipment for use in spacebased applications. The microgravity experiments will focus on the visualization of bubble formation and shape during boiling. Heat fluxes on the boiling surface will be measured, and, together with the measured driving temperature differences, used to plot boiling curves for different electric field magnitudes. Bubble formation and boiling processes were found to be extremely sensitive to g-jitter. The duration of the experimental run is critical in order to achieve steady state in microgravity experiments. The International Space Station provides conditions suitable for such experiments. The experimental apparatus to be used in the study is described in the paper. The apparatus will be tested in the KC-135 first, and microgravity experiments will be conducted on board of the International Space Station using the Microgravity Science Glovebox as the experimental platform.

Development and validation of a predictive model for the influences of selected product and process variables on ascorbic acid degradation in simulated fruit juice.

PubMed

Gabriel, Alonzo A; Cayabyab, Jochelle Elysse C; Tan, Athalie Kaye L; Corook, Mark Lester F; Ables, Errol John O; Tiangson-Bayaga, Cecile Leah P

2015-06-15

A predictive response surface model for the influences of product (soluble solids and titratable acidity) and process (temperature and heating time) parameters on the degradation of ascorbic acid (AA) in heated simulated fruit juices (SFJs) was established. Physicochemical property ranges of freshly squeezed and processed juices, and a previously established decimal reduction times of Escherichiacoli O157:H7 at different heating temperatures were used in establishing a Central Composite Design of Experiment that determined the combinations of product and process variable used in the model building. Only the individual linear effects of temperature and heating time significantly (P<0.05) affected AA reduction (%AAr). Validating systems either over- or underestimated actual %AAr with bias factors 0.80-1.20. However, all validating systems still resulted in acceptable predictive efficacy, with accuracy factor 1.00-1.26. The model may be useful in establishing unique process schedules for specific products, for the simultaneous control and improvement of food safety and quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanical and Metallurgical Evolution of Stainless Steel 321 in a Multi-step Forming Process

NASA Astrophysics Data System (ADS)

Anderson, M.; Bridier, F.; Gholipour, J.; Jahazi, M.; Wanjara, P.; Bocher, P.; Savoie, J.

2016-04-01

This paper examines the metallurgical evolution of AISI Stainless Steel 321 (SS 321) during multi-step forming, a process that involves cycles of deformation with intermediate heat treatment steps. The multi-step forming process was simulated by implementing interrupted uniaxial tensile testing experiments. Evolution of the mechanical properties as well as the microstructural features, such as twins and textures of the austenite and martensite phases, was studied as a function of the multi-step forming process. The characteristics of the Strain-Induced Martensite (SIM) were also documented for each deformation step and intermediate stress relief heat treatment. The results indicated that the intermediate heat treatments considerably increased the formability of SS 321. Texture analysis showed that the effect of the intermediate heat treatment on the austenite was minor and led to partial recrystallization, while deformation was observed to reinforce the crystallographic texture of austenite. For the SIM, an Olson-Cohen equation type was identified to analytically predict its formation during the multi-step forming process. The generated SIM was textured and weakened with increasing deformation.

Direct numerical simulation of transitional and turbulent flow over a heated flat plate using finite-difference schemes

NASA Technical Reports Server (NTRS)

Madavan, Nateri K.

1995-01-01

This report deals with the direct numerical simulation of transitional and turbulent flow at low Mach numbers using high-order-accurate finite-difference techniques. A computation of transition to turbulence of the spatially-evolving boundary layer on a heated flat plate in the presence of relatively high freestream turbulence was performed. The geometry and flow conditions were chosen to match earlier experiments. The development of the momentum and thermal boundary layers was documented. Velocity and temperature profiles, as well as distributions of skin friction, surface heat transfer rate, Reynolds shear stress, and turbulent heat flux, were shown to compare well with experiment. The results indicate that the essential features of the transition process have been captured. The numerical method used here can be applied to complex geometries in a straightforward manner.

Forging; Heat Treating and Testing; Technically Oriented Industrial Materials and Process 1: 5898.05.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

The course provides students with advanced and exploratory experience in the area of plastic deformation of metals and in the changing of the physical characteristics of metals by the controlled application and timed removal of heat. Course content includes goals, specific objectives, safety in forge work, forging tools and equipment, industrial…

Experimental Validation for Hot Stamping Process by Using Taguchi Method

NASA Astrophysics Data System (ADS)

Fawzi Zamri, Mohd; Lim, Syh Kai; Razlan Yusoff, Ahmad

2016-02-01

Due to the demand for reduction in gas emissions, energy saving and producing safer vehicles has driven the development of Ultra High Strength Steel (UHSS) material. To strengthen UHSS material such as boron steel, it needed to undergo a process of hot stamping for heating at certain temperature and time. In this paper, Taguchi method is applied to determine the appropriate parameter of thickness, heating temperature and heating time to achieve optimum strength of boron steel. The experiment is conducted by using flat square shape of hot stamping tool with tensile dog bone as a blank product. Then, the value of tensile strength and hardness is measured as response. The results showed that the lower thickness, higher heating temperature and heating time give the higher strength and hardness for the final product. In conclusion, boron steel blank are able to achieve up to 1200 MPa tensile strength and 650 HV of hardness.

Magma Mixing Chronometry: Quantitative 3D Tomographic Analysis of Biotite Breakdown in Heating Experiments

NASA Astrophysics Data System (ADS)

Grocke, S. B.; Andrews, B. J.; Manga, M.; Quinn, E. T.

2015-12-01

Dacite lavas from Chaos Crags, Lassen Volcanic Center, CA contain inclusions of more mafic magmas, suggesting that mixing or mingling of magmas occurred just prior to lava dome extrusion, and perhaps triggered the eruption. The timescales between the mixing event and eruption are unknown, but reaction rims on biotite grains hosted in the Chaos Crags dacite may provide a record of the timescale (i.e., chronometer) between mixing and eruption. To quantify the effect of pre-eruptive heating on the formation of reaction rims on biotite, we conducted isobaric (150 MPa), H2O-saturated, heating experiments on the dacite end-member. In heating experiments, we held the natural dacite at 800°C and 150MPa for 96 hours and then isobarically heated the experiments to 825 and 850°C (temperatures above the biotite liquidus, <815°C at 150MPa) for durations ≤96 hours. We analyzed run products using high-resolution SEM imaging and synchrotron-based X-ray tomography, which provides a 3-dimensional rendering of biotite breakdown reaction products and textures. X-ray tomography images of experimental run products reveal that in all heating experiments, biotite breakdown occurs and reaction products include orthopyroxenes, Fe-Ti oxides, and vapor (inferred from presence of bubbles). Experiments heated to 850°C for 96 h show extensive breakdown, consisting of large orthopyroxene crystals, Fe-Ti oxide laths (<100μm), and bubbles. When the process of biotite breakdown goes to completion, the resulting H2O bubble comprises roughly the equivalent volume of the original biotite crystal. This observation suggests that biotite breakdown can add significant water to the melt and lead to extensive bubble formation. Although bubble expansion and magma flow may disrupt the reaction products in some magmas, our experiments suggest that biotite breakdown textures in natural samples can be used as a chronometer for pre-eruptive magma mixing.

Improved silicon nitride for advanced heat engines

NASA Technical Reports Server (NTRS)

Yeh, Hun C.; Fang, Ho T.

1987-01-01

The technology base required to fabricate silicon nitride components with the strength, reliability, and reproducibility necessary for actual heat engine applications is presented. Task 2 was set up to develop test bars with high Weibull slope and greater high temperature strength, and to conduct an initial net shape component fabrication evaluation. Screening experiments were performed in Task 7 on advanced materials and processing for input to Task 2. The technical efforts performed in the second year of a 5-yr program are covered. The first iteration of Task 2 was completed as planned. Two half-replicated, fractional factorial (2 sup 5), statistically designed matrix experiments were conducted. These experiments have identified Denka 9FW Si3N4 as an alternate raw material to GTE SN502 Si3N4 for subsequent process evaluation. A detailed statistical analysis was conducted to correlate processing conditions with as-processed test bar properties. One processing condition produced a material with a 97 ksi average room temperature MOR (100 percent of goal) with 13.2 Weibull slope (83 percent of goal); another condition produced 86 ksi (6 percent over baseline) room temperature strength with a Weibull slope of 20 (125 percent of goal).

A heating experiment in the argillites in the Meuse/Haute-Marne underground research laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wileveau, Yannick; Su, Kun; Ghoreychi, Mehdi

2007-07-01

A heating experiment named TER is being conducted with the objectives to identify the thermal properties, as well as to enhance the knowledge on THM processes in the Callovo-Oxfordian clay at the Meuse/Haute Marne Underground Research Laboratory (France). The in situ experiment has being switched on from early 2006. The heater, 3 m length, is designed to inject the power in the undisturbed zone at 6 m from the gallery wall. A heater packer is inflated in a metallic tubing. During the experiment, numerous sensors are emplaced in the surrounding rock and are experienced to monitor the evolution in temperature,more » pore-water pressure and deformation. The models and numerical codes applied should be validated by comparing the modeling results with the measurements. In parallel, some lab testing have been achieved in order to compare the results given with two different scales (cm up to meter scale). In this paper, we present a general description of the TER experiment with installation of the heater equipment and the surrounding instrumentation. Details of the in situ measurements of temperature, pore-pressure and strain evolutions are given for the several heating and cooling phases. The thermal conductivity and some predominant parameters in THM processes (as linear thermal expansion coefficient and permeability) will be discussed. (authors)« less

Heat transfer simulation and retort program adjustment for thermal processing of wheat based Haleem in semi-rigid aluminum containers.

PubMed

Vatankhah, Hamed; Zamindar, Nafiseh; Shahedi Baghekhandan, Mohammad

2015-10-01

A mixed computational strategy was used to simulate and optimize the thermal processing of Haleem, an ancient eastern food, in semi-rigid aluminum containers. Average temperature values of the experiments showed no significant difference (α = 0.05) in contrast to the predicted temperatures at the same positions. According to the model, the slowest heating zone was located in geometrical center of the container. The container geometrical center F0 was estimated to be 23.8 min. A 19 min processing time interval decrease in holding time of the treatment was estimated to optimize the heating operation since the preferred F0 of some starch or meat based fluid foods is about 4.8-7.5 min.

On numerical model of time-dependent processes in three-dimensional porous heat-releasing objects

NASA Astrophysics Data System (ADS)

Lutsenko, Nickolay A.

2016-10-01

The gas flows in the gravity field through porous objects with heat-releasing sources are investigated when the self-regulation of the flow rate of the gas passing through the porous object takes place. Such objects can appear after various natural or man-made disasters (like the exploded unit of the Chernobyl NPP). The mathematical model and the original numerical method, based on a combination of explicit and implicit finite difference schemes, are developed for investigating the time-dependent processes in 3D porous energy-releasing objects. The advantage of the numerical model is its ability to describe unsteady processes under both natural convection and forced filtration. The gas cooling of 3D porous objects with different distribution of heat sources is studied using computational experiment.

A Study of the Response of Deep Tropical Clouds to Mesoscale Processes. Part 1; Modeling Strategies and Simulations of TOGA-COARE Convective Systems

NASA Technical Reports Server (NTRS)

Johnson, Daniel E.; Tao, W.-K.; Simpson, J.; Sui, C.-H.; Einaudi, Franco (Technical Monitor)

2001-01-01

Interactions between deep tropical clouds over the western Pacific warm pool and the larger-scale environment are key to understanding climate change. Cloud models are an extremely useful tool in simulating and providing statistical information on heat and moisture transfer processes between cloud systems and the environment, and can therefore be utilized to substantially improve cloud parameterizations in climate models. In this paper, the Goddard Cumulus Ensemble (GCE) cloud-resolving model is used in multi-day simulations of deep tropical convective activity over the Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). Large-scale temperature and moisture advective tendencies, and horizontal momentum from the TOGA-COARE Intensive Flux Array (IFA) region, are applied to the GCE version which incorporates cyclical boundary conditions. Sensitivity experiments show that grid domain size produces the largest response to domain-mean temperature and moisture deviations, as well as cloudiness, when compared to grid horizontal or vertical resolution, and advection scheme. It is found that a minimum grid-domain size of 500 km is needed to adequately resolve the convective cloud features. The control experiment shows that the atmospheric heating and moistening is primarily a response to cloud latent processes of condensation/evaporation, and deposition/sublimation, and to a lesser extent, melting of ice particles. Air-sea exchange of heat and moisture is found to be significant, but of secondary importance, while the radiational response is small. The simulated rainfall and atmospheric heating and moistening, agrees well with observations, and performs favorably to other models simulating this case.

Vapor Compression and Thermoelectric Heat Pump Heat Exchangers for a Condensate Distillation System: Design and Experiment

NASA Technical Reports Server (NTRS)

Erickson, Lisa R.; Ungar, Eugene K.

2013-01-01

Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.

Measurement of heat pump processes induced by laser radiation

NASA Technical Reports Server (NTRS)

Garbuny, M.; Henningsen, T.

1983-01-01

A series of experiments was performed in which a suitably tuned CO2 laser, frequency doubled by a Tl3AsSe37 crystal, was brought into resonance with a P-line or two R-lines in the fundamental vibration spectrum of CO. Cooling or heating produced by absorption in CO was measured in a gas-thermometer arrangement. P-line cooling and R-line heating could be demonstrated, measured, and compared. The experiments were continued with CO mixed with N2 added in partial pressures from 9 to 200 Torr. It was found that an efficient collisional resonance energy transfer from CO to N2 existed which increased the cooling effects by one to two orders of magnitude over those in pure CO. Temperature reductions in the order of tens of degrees Kelvin were obtained by a single pulse in the core of the irradiated volume. These measurements followed predicted values rather closely, and it is expected that increase of pulse energies and durations will enhance the heat pump effects. The experiments confirm the feasibility of quasi-isentropic engines which convert laser power into work without the need for heat rejection. Of more immediate potential interest is the possibility of remotely powered heat pumps for cryogenic use, such applications are discussed to the extent possible at the present stage.

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

NASA Astrophysics Data System (ADS)

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.

Energy Conversion Loop: A Testbed for Nuclear Hybrid Energy Systems Use in Biomass Pyrolysis

NASA Astrophysics Data System (ADS)

Verner, Kelley M.

Nuclear hybrid energy systems are a possible solution for contemporary energy challenges. Nuclear energy produces electricity without greenhouse gas emissions. However, nuclear power production is not as flexible as electrical grids demand and renewables create highly variable electricity. Nuclear hybrid energy systems are able to address both of these problems. Wasted heat can be used in processes such as desalination, hydrogen production, or biofuel production. This research explores the possible uses of nuclear process heat in bio-oil production via biomass pyrolysis. The energy conversion loop is a testbed designed and built to mimic the heat from a nuclear reactor. Small scale biomass pyrolysis experiments were performed and compared to results from the energy conversion loop tests to determine future pyrolysis experimentation with the energy conversion loop. Further improvements must be made to the energy conversion loop before more complex experiments may be performed. The current conditions produced by the energy conversion loop are not conducive for current biomass pyrolysis experimentation.tion.

Modelling of heat transfer during torrefaction of large lignocellulosic biomass

NASA Astrophysics Data System (ADS)

Regmi, Bharat; Arku, Precious; Tasnim, Syeda Humaira; Mahmud, Shohel; Dutta, Animesh

2018-02-01

Preparation of feedstock is a major energy intensive process for the thermochemical conversion of biomass into fuel. By eliminating the need to grind biomass prior to the torrefaction process, there would be a potential gain in the energy requirements as the entire step would be eliminated. In regards to a commercialization of torrefaction technology, this study has examined heat transfer inside large cylindrical biomass both numerically and experimentally during torrefaction. A numerical axis-symmetrical 2-D model for heat transfer during torrefaction at 270°C for 1 h was created in COMSOL Multiphysics 5.1 considering heat generation evaluated from the experiment. The model analyzed the temperature distribution within the core and on the surface of biomass during torrefaction for various sizes. The model results showed similarities with experimental results. The effect of L/D ratio on temperature distribution within biomass was observed by varying length and diameter and compared with experiments in literature to find out an optimal range of cylindrical biomass size suitable for torrefaction. The research demonstrated that a cylindrical biomass sample of 50 mm length with L/D ratio of 2 can be torrefied with a core-surface temperature difference of less than 30 °C. The research also demonstrated that sample length has a negligible effect on core-surface temperature difference during torrefaction when the diameter is fixed at 25 mm. This information will help to design a torrefaction processing system and develop a value chain for biomass supply without using an energy-intensive grinding process.

Modelling of heat transfer during torrefaction of large lignocellulosic biomass

NASA Astrophysics Data System (ADS)

Regmi, Bharat; Arku, Precious; Tasnim, Syeda Humaira; Mahmud, Shohel; Dutta, Animesh

2018-07-01

Preparation of feedstock is a major energy intensive process for the thermochemical conversion of biomass into fuel. By eliminating the need to grind biomass prior to the torrefaction process, there would be a potential gain in the energy requirements as the entire step would be eliminated. In regards to a commercialization of torrefaction technology, this study has examined heat transfer inside large cylindrical biomass both numerically and experimentally during torrefaction. A numerical axis-symmetrical 2-D model for heat transfer during torrefaction at 270°C for 1 h was created in COMSOL Multiphysics 5.1 considering heat generation evaluated from the experiment. The model analyzed the temperature distribution within the core and on the surface of biomass during torrefaction for various sizes. The model results showed similarities with experimental results. The effect of L/D ratio on temperature distribution within biomass was observed by varying length and diameter and compared with experiments in literature to find out an optimal range of cylindrical biomass size suitable for torrefaction. The research demonstrated that a cylindrical biomass sample of 50 mm length with L/D ratio of 2 can be torrefied with a core-surface temperature difference of less than 30 °C. The research also demonstrated that sample length has a negligible effect on core-surface temperature difference during torrefaction when the diameter is fixed at 25 mm. This information will help to design a torrefaction processing system and develop a value chain for biomass supply without using an energy-intensive grinding process.

Extraction and Capture of Water from Martian Regolith Experimental Proof-of-Concept

NASA Technical Reports Server (NTRS)

Linne, Diane; Kleinhenz, Julie; Bauman, Steve; Johnson, Kyle

2016-01-01

Mars Design Reference Architecture 5.0:Lists in-situ resource utilization (ISRU) as enabling for robust human Mars missionsLO2LCH4 ascent propulsion 25,000 kg oxygen from atmosphere for ascent and life support Atmospheric based ISRU processes less operationally complex than surface based limited concept evaluation to date and Mars surface water property and distribution uncertainty would not allow [Mars soil water processing] to be base lined at this time Limited Concept Evaluation to Date Lunar regolith O2 extraction processing experience Lunar regolith is fluidized and heated to high temperatures with H2 to produce H2O from iron-bearing minerals Mars similarity concept: Soil placed in fluidized bed reactor Heated to moderate temperatures Inert gas flow used to fluidize the bed and help with water desorption Challenges: High-temperature dusty seals Working gas requires downstream separation and recycling to reduce consumables loss Batch process heating thermally inefficient.

Thermal energy management process experiment

NASA Technical Reports Server (NTRS)

Ollendorf, S.

1984-01-01

The thermal energy management processes experiment (TEMP) will demonstrate that through the use of two-phase flow technology, thermal systems can be significantly enhanced by increasing heat transport capabilities at reduced power consumption while operating within narrow temperature limits. It has been noted that such phenomena as excess fluid puddling, priming, stratification, and surface tension effects all tend to mask the performance of two-phase flow systems in a 1-g field. The flight experiment approach would be to attack the experiment to an appropriate mounting surface with a 15 to 20 meter effective length and provide a heat input and output station in the form of heaters and a radiator. Using environmental data, the size, location, and orientation of the experiment can be optimized. The approach would be to provide a self-contained panel and mount it to the STEP through a frame. A small electronics package would be developed to interface with the STEP avionics for command and data handling. During the flight, heaters on the evaporator will be exercised to determine performance. Flight data will be evaluated against the ground tests to determine any anomalous behavior.

Radiographic measurements of viscosity in Comp B

NASA Astrophysics Data System (ADS)

Oschwald, Dave; Suvorova, Natalya; Remelius, Dennis; Henson, Bryan; Smilowitz, Laura

2017-06-01

Experiments were preformed using standard Composition B which is an explosive consisting of castable mixtures of RDX and TNT. Comp B is most commonly described as 60/40 RDX/TNT. This material was pressed into cylindrical samples with a spherical bead of various materials imbedded into the center. The samples were then incased into aluminum tubes that were wrapped in heat tape for external heating. A table top CW X-ray system coupled with a scintillator/camera system was used to observe the heating process and the time to temperature where the bead started to move inside the melt of the TNT due to gravity. These experiments where aiming to measure viscosity of Comp B versus temperature. The beads embedded into the pellets were made of various materials and differ in density and sizes to increase accuracy of the viscosity measurements. This work will focus on the experimental set-up and the suite of diagnostic used in these experiments.

Hardness of H13 Tool Steel After Non-isothermal Tempering

NASA Astrophysics Data System (ADS)

Nelson, E.; Kohli, A.; Poirier, D. R.

2018-04-01

A direct method to calculate the tempering response of a tool steel (H13) that exhibits secondary hardening is presented. Based on the traditional method of presenting tempering response in terms of isothermal tempering, we show that the tempering response for a steel undergoing a non-isothermal tempering schedule can be predicted. Experiments comprised (1) isothermal tempering, (2) non-isothermal tempering pertaining to a relatively slow heating to process-temperature and (3) fast-heating cycles that are relevant to tempering by induction heating. After establishing the tempering response of the steel under simple isothermal conditions, the tempering response can be applied to non-isothermal tempering by using a numerical method to calculate the tempering parameter. Calculated results are verified by the experiments.

Improvement of efficiency and temperature control of induction heating vapor source on electron cyclotron resonance ion source.

PubMed

Takenaka, T; Kiriyama, R; Muramatsu, M; Kitagawa, A; Uchida, T; Kurisu, Y; Nozaki, D; Yano, K; Yoshida, Y; Sato, F; Kato, Y; Iida, T

2012-02-01

An electron cyclotron resonance ion source (ECRIS) is used to generate multicharged ions for many kinds of the fields. We have developed an evaporator by using induction heating method that can generate pure vapor from solid state materials in ECRIS. We develop the new matching and protecting circuit by which we can precisely control the temperature of the induction heating evaporator. We can control the temperature within ±15 °C around 1400 °C under the operation pressure about 10(-4) Pa. We are able to use this evaporator for experiment of synthesizing process to need pure vapor under enough low pressure, e.g., experiment of generation of endohedral Fe-fullerene at the ECRIS.

Integration of experimental and computational methods for identifying geometric, thermal and diffusive properties of biomaterials

NASA Astrophysics Data System (ADS)

Weres, Jerzy; Kujawa, Sebastian; Olek, Wiesław; Czajkowski, Łukasz

2016-04-01

Knowledge of physical properties of biomaterials is important in understanding and designing agri-food and wood processing industries. In the study presented in this paper computational methods were developed and combined with experiments to enhance identification of agri-food and forest product properties, and to predict heat and water transport in such products. They were based on the finite element model of heat and water transport and supplemented with experimental data. Algorithms were proposed for image processing, geometry meshing, and inverse/direct finite element modelling. The resulting software system was composed of integrated subsystems for 3D geometry data acquisition and mesh generation, for 3D geometry modelling and visualization, and for inverse/direct problem computations for the heat and water transport processes. Auxiliary packages were developed to assess performance, accuracy and unification of data access. The software was validated by identifying selected properties and using the estimated values to predict the examined processes, and then comparing predictions to experimental data. The geometry, thermal conductivity, specific heat, coefficient of water diffusion, equilibrium water content and convective heat and water transfer coefficients in the boundary layer were analysed. The estimated values, used as an input for simulation of the examined processes, enabled reduction in the uncertainty associated with predictions.

Experimental research and numerical simulation on cryogenic line chill-down process

NASA Astrophysics Data System (ADS)

Jin, Lingxue; Cho, Hyokjin; Lee, Cheonkyu; Jeong, Sangkwon

2018-01-01

The empirical heat transfer correlations are suggested for the fast cool down process of the cryogenic transfer line from room temperature to cryogenic temperature. The correlations include the heat transfer coefficient (HTC) correlations for single-phase gas convection and film boiling regimes, minimum heat flux (MHF) temperature, critical heat flux (CHF) temperature and CHF. The correlations are obtained from the experimental measurements. The experiments are conducted on a 12.7 mm outer diameter (OD), 1.25 mm wall thickness and 7 m long stainless steel horizontal pipe with liquid nitrogen (LN2). The effect of the lengthwise position is verified by measuring the temperature profiles in near the inlet and the outlet of the transfer line. The newly suggested heat transfer correlations are applied to the one-dimensional homogeneous transient model to simulate the cryogenic line chill-down process, and the chill-down time and the cryogen consumption are well predicted in the mass flux range from 26.0 kg/m2 s to 73.6 kg/m2 s through the correlations.

Experimental Determination of in Situ Utilization of Lunar Regolith for Thermal Energy Storage

NASA Technical Reports Server (NTRS)

Richter, Scott W.

1993-01-01

A Lunar Thermal Energy from Regolith (LUTHER) experiment has been designed and fabricated at the NASA Lewis Research Center to determine the feasibility of using lunar soil as thermal energy storage media. The experimental apparatus includes an alumina ceramic canister (25.4 cm diameter by 45.7 cm length) which contains simulated lunar regolith, a heater (either radiative or conductive), 9 heat shields, a heat transfer cold jacket, and 19 type B platinum rhodium thermocouples. The simulated lunar regolith is a basalt, mined and processed by the University of Minnesota, that closely resembles the lunar basalt returned to earth by the Apollo missions. The experiment will test the effects of vacuum, particle size, and density on the thermophysical properties of the regolith. The properties include melt temperature (range), specific heat, thermal conductivity, and latent heat of storage. Two separate tests, using two different heaters, will be performed to study the effect of heating the system using radiative and conductive heat transfer. The physical characteristics of the melt pattern, material compatibility of the molten regolith, and the volatile gas emission will be investigated by heating a portion of the lunar regolith to its melting temperature (1435 K) in a 10(exp -4) pascal vacuum chamber, equipped with a gas spectrum analyzer. A finite differencing SINDA model was developed at NASA Lewis Research Center to predict the performance of the LUTHER experiment. The analytical results of the code will be compared with the experimental data generated by the LUTHER experiment. The code will predict the effects of vacuum, particle size, and density has on the heat transfer to the simulated regolith.

The direct heat measurement of mechanical energy storage metal-organic frameworks.

PubMed

Rodriguez, Julien; Beurroies, Isabelle; Loiseau, Thierry; Denoyel, Renaud; Llewellyn, Philip L

2015-04-07

In any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal-organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL-53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature and heat flux datasets of a complex object in a fire plume for the validation of fire and thermal response codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jernigan, Dann A.; Blanchat, Thomas K.

It is necessary to improve understanding and develop temporally- and spatially-resolved integral scale validation data of the heat flux incident to a complex object in addition to measuring the thermal response of said object located within the fire plume for the validation of the SIERRA/FUEGO/SYRINX fire and SIERRA/CALORE codes. To meet this objective, a complex calorimeter with sufficient instrumentation to allow validation of the coupling between FUEGO/SYRINX/CALORE has been designed, fabricated, and tested in the Fire Laboratory for Accreditation of Models and Experiments (FLAME) facility. Validation experiments are specifically designed for direct comparison with the computational predictions. Making meaningful comparisonmore » between the computational and experimental results requires careful characterization and control of the experimental features or parameters used as inputs into the computational model. Validation experiments must be designed to capture the essential physical phenomena, including all relevant initial and boundary conditions. This report presents the data validation steps and processes, the results of the penlight radiant heat experiments (for the purpose of validating the CALORE heat transfer modeling of the complex calorimeter), and the results of the fire tests in FLAME.« less

Recent changes in the summer monsoon circulation and their impact on dynamics and thermodynamics of the Arabian Sea

NASA Astrophysics Data System (ADS)

Pratik, Kad; Parekh, Anant; Karmakar, Ananya; Chowdary, Jasti S.; Gnanaseelan, C.

2018-05-01

The present study examines changes in the low-level summer monsoon circulation over the Arabian Sea and their impact on the ocean dynamics using reanalysis data. The study confirms intensification and northward migration of low-level jet during 1979 to 2015. Further during the study period, an increase in the Arabian Sea upper ocean heat content is found in spite of a decreasing trend in the net surface heat flux, indicating the possible role of ocean dynamics in the upper ocean warming. Increase in the anti-cyclonic wind stress curl associated with the change in the monsoon circulation induces downwelling over the central Arabian Sea, favoring upper ocean warming. The decreasing trend of southward Ekman transport, a mechanism transporting heat from the land-locked north Indian Ocean to southern latitudes, also supports increasing trend of the upper ocean heat content. To reinstate and quantify the role of changing monsoon circulation in increasing the heat content over the Arabian Sea, sensitivity experiment is carried out using ocean general circulation model. In this experiment, the model is forced by inter-annual momentum forcing while rest of the forcing is climatological. Experiment reveals that the changing monsoon circulation increases the upper ocean heat content, effectively by enhancing downwelling processes and reducing southward heat transport, which strongly endorses our hypothesis that changing ocean dynamics associated with low-level monsoon circulation is causing the increasing trend in the heat content of the Arabian Sea.

Experiments and Modeling in Support of Generic Salt Repository Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourret, Suzanne Michelle; Stauffer, Philip H.; Weaver, Douglas James

Salt is an attractive material for the disposition of heat generating nuclear waste (HGNW) because of its self-sealing, viscoplastic, and reconsolidation properties (Hansen and Leigh, 2012). The rate at which salt consolidates and the properties of the consolidated salt depend on the composition of the salt, including its content in accessory minerals and moisture, and the temperature under which consolidation occurs. Physicochemical processes, such as mineral hydration/dehydration salt dissolution and precipitation play a significant role in defining the rate of salt structure changes. Understanding the behavior of these complex processes is paramount when considering safe design for disposal of heat-generatingmore » nuclear waste (HGNW) in salt formations, so experimentation and modeling is underway to characterize these processes. This report presents experiments and simulations in support of the DOE-NE Used Fuel Disposition Campaign (UFDC) for development of drift-scale, in-situ field testing of HGNW in salt formations.« less

Study the effect of elevated dies temperature on aluminium and steel round deep drawing

NASA Astrophysics Data System (ADS)

Lean, Yeong Wei; Azuddin, M.

2016-02-01

Round deep drawing operation can only be realized by expensive multi-step production processes. To reduce the cost of processes while expecting an acceptable result, round deep drawing can be done at elevated temperature. There are 3 common problems which are fracture, wrinkling and earing of deep drawing a round cup. The main objective is to investigate the effect of dies temperature on aluminium and steel round deep drawing; with a sub-objective of eliminate fracture and reducing wrinkling effect. Experimental method is conducted with 3 different techniques on heating the die. The techniques are heating both upper and lower dies, heating only the upper dies, and heating only the lower dies. 4 different temperatures has been chosen throughout the experiment. The experimental result then will be compared with finite element analysis software. There is a positive result from steel material on heating both upper and lower dies, where the simulation result shows comparable as experimental result. Heating both upper and lower dies will be the best among 3 types of heating techniques.

Visualization of various working fluids flow regimes in gravity heat pipe

NASA Astrophysics Data System (ADS)

Nemec, Patrik

Heat pipe is device working with phase changes of working fluid inside hermetically closed pipe at specific pressure. The phase changes of working fluid from fluid to vapour and vice versa help heat pipe to transport high heat flux. Amount of heat flux transferred by heat pipe, of course depends on kind of working fluid. The article deal about visualization of various working fluids flow regimes in glass gravity heat pipe by high speed camera and processes casing inside during heat pipe operation. Experiment working fluid flow visualization is performed with two glass heat pipes with different inner diameter (13 mm and 22 mm) filled with water, ethanol and fluorinert FC 72. The working fluid flow visualization explains the phenomena as a working fluid boiling, nucleation of bubbles, and vapour condensation on the wall, vapour and condensate flow interaction, flow down condensate film thickness on the wall occurred during the heat pipe operation.

Influences of elevated heating effect by the Himalaya on the changes in Asian summer monsoon

NASA Astrophysics Data System (ADS)

He, Bian

2017-04-01

Based on a series of topographical and thermal sensitivity experiments, the physical processes on the changes of Asian summer monsoon caused by the Himalaya elevated heating were investigated. Six different Himalaya-Iranian Plateau mountain heights were used: 0%, 20%, 40%, 60%, 80%, and 100% in the first group (called HIM). The no sensible heating experiments (called HIM_NS) were also performed with the same six mountain heights but the surface sensible heating was not allowed to heat the atmosphere. The results indicate that the elevated heating effect of Himalaya gradually intensified when Himalaya uplift. The establishment of SASM over South Asian land which is characterized by the strong precipitation over South slope of Tibetan Plateau and the huge warm anticyclone in the upper troposphere are in proportion to the elevated heating effect of Himalaya. Further analysis suggests that the surface heat fluxes over Himalaya keep almost unchanged during the uplifting, but the lifted condensation level reduces gradually over the regions where the mountain uplift. The condensation moisturing increases correspondingly and leads to the increase of latent heating in the upper troposphere. Therefore, the positive feedback between the moist convection over south slope of Himalaya and monsoon circulation over Indian sub-continent forms and the successive precipitation over South Asian land is maintained.

Applications of Radiative Heating for Space Exploration

NASA Technical Reports Server (NTRS)

Brandis, Aaron

2017-01-01

Vehicles entering planetary atmospheres at high speeds (6 - 12 kms) experience intense heating by flows with temperatures of the order 10 000K. The flow around the vehicle experiences significant dissociation and ionization and is characterized by thermal and chemical non-equilibrium near the shock front, relaxing toward equilibrium. Emission from the plasma is intense enough to impart a significant heat flux on the entering spacecraft, making it necessary to predict the magnitude of radiative heating. Shock tubes represent a unique method capable of characterizing these processes in a flight-similar environment. The Electric Arc Shock tube (EAST) facility is one of the only facilities in its class, able to produce hypersonic flows at speeds up to Mach 50. This talk will review the characterization of radiation measured in EAST with simulations by the codes DPLR and NEQAIR, and in particular, focus on the impact these analyses have on recent missions to explore the solar system.

Laser materials processing facility

NASA Technical Reports Server (NTRS)

Haggerty, J. S.

1982-01-01

The laser materials processing facility and its capabilities are described. A CO2 laser with continuous wave, repetitive pulse, and shaped power-time cycles is employed. The laser heated crystal growth station was used to produce metal and metal oxide single crystals and for cutting and shaping experiments using Si3N4 to displace diamond shaping processes.

Performance of the cometary experiment MUPUS on the body Earth

NASA Astrophysics Data System (ADS)

Marczewski, W.; Usowicz, B.; Schröer, K.; Seiferlin, K.; Spohn, T.

2003-04-01

Thermal experiment MUPUS for the Rosetta mission was extensively experience in field and laboratory conditions to predict its performance under physical processes available on the Earth. The goal was not guessing a cometary material in the ground but available behavior of thermal sensor responses monitoring mass and energy transfer. The processes expected on a comet are different in composition and environmental from those met on the Earth but basically similar in physics. Nature of energy powering the processes is also essentially the same - solar radiation. Several simple laboratory experiments with freezing and thawing with water ice, with mixture of water and oil and water layers strongly diverged by salinity revealed capability of recognition layered structure of the medium under test. More over effects of slow convection and latent heat related to the layers are also observed well. Cometary environment without atmosphere makes process of sublimation dominant. Open air conditions on the Earth may also offer a change of state in matter but between different phases. Learning temperature gradient in snow layers under thawing show that effects stimulated by a cause of daily cycling may be detected thermally. Results from investigations in snow made on Spitzbergen are good proofs on capability of the method. Relevance of thermal effects to heat powered processes of mass transport in the matter of ground is meaningful for the cometary experiment of MUPUS and for Earth sciences much concerned on water, gas and solid matter transport in the terrestrial ground. Results leading to energy balance studied on the Earth surface may be interesting also for the experiment on the comet and are to be discussed.

Correlation of heat transfer coefficient in quenching process using ABAQUS

NASA Astrophysics Data System (ADS)

Davare, Sandeep Kedarnath; Balachandran, G.; Singh, R. K. P.

2018-04-01

During the heat treatment by quenching in a liquid medium the convective heat transfer coefficient plays a crucial role in the extraction of heat. The heat extraction ultimately influences the cooling rate and hence the hardness and mechanical properties. A Finite Element analysis of quenching a simple flat copper sample with different orientation of sample and with different quenchant temperatures were carried out to check and verify the results obtained from the experiments. The heat transfer coefficient (HTC) was calculated from temperature history in a simple flat copper disc sample experimentally. This HTC data was further used as input to simulation software and the cooling curves were back calculated. The results obtained from software and using experimentation shows nearly consistent values.

Transpiration Cooling Experiment

NASA Technical Reports Server (NTRS)

Song, Kyo D.; Ries, Heidi R.; Scotti, Stephen J.; Choi, Sang H.

1997-01-01

The transpiration cooling method was considered for a scram-jet engine to accommodate thermally the situation where a very high heat flux (200 Btu/sq. ft sec) from hydrogen fuel combustion process is imposed to the engine walls. In a scram-jet engine, a small portion of hydrogen fuel passes through the porous walls of the engine combustor to cool the engine walls and at the same time the rest passes along combustion chamber walls and is preheated. Such a regenerative system promises simultaneously cooling of engine combustor and preheating the cryogenic fuel. In the experiment, an optical heating method was used to provide a heat flux of 200 Btu/sq. ft sec to the cylindrical surface of a porous stainless steel specimen which carried helium gas. The cooling efficiencies by transpiration were studied for specimens with various porosity. The experiments of various test specimens under high heat flux have revealed a phenomenon that chokes the medium flow when passing through a porous structure. This research includes the analysis of the system and a scaling conversion study that interprets the results from helium into the case when hydrogen medium is used.

Seasonal changes in the atmospheric heat balance simulated by the GISS general circulation model

NASA Technical Reports Server (NTRS)

Stone, P. H.; Chow, S.; Helfand, H. M.; Quirk, W. J.; Somerville, R. C. J.

1975-01-01

Tests of the ability of numerical general circulation models to simulate the atmosphere have focussed so far on simulations of the January climatology. These models generally present boundary conditions such as sea surface temperature, but this does not prevent testing their ability to simulate seasonal changes in atmospheric processes that accompany presented seasonal changes in boundary conditions. Experiments to simulate changes in the zonally averaged heat balance are discussed since many simplified models of climatic processes are based solely on this balance.

[A review on research of land surface water and heat fluxes].

PubMed

Sun, Rui; Liu, Changming

2003-03-01

Many field experiments were done, and soil-vegetation-atmosphere transfer(SVAT) models were stablished to estimate land surface heat fluxes. In this paper, the processes of experimental research on land surface water and heat fluxes are reviewed, and three kinds of SVAT model(single layer model, two layer model and multi-layer model) are analyzed. Remote sensing data are widely used to estimate land surface heat fluxes. Based on remote sensing and energy balance equation, different models such as simplified model, single layer model, extra resistance model, crop water stress index model and two source resistance model are developed to estimate land surface heat fluxes and evapotranspiration. These models are also analyzed in this paper.

Thermally-driven Coupled THM Processes in Shales

NASA Astrophysics Data System (ADS)

Rutqvist, J.

2017-12-01

Temperature changes can trigger strongly coupled thermal-hydrological-mechanical (THM) processes in shales that are important to a number of subsurface energy applications, including geologic nuclear waste disposal and hydrocarbon extraction. These coupled processes include (1) direct pore-volume couplings, by thermal expansion of trapped pore-fluid that triggers instantaneous two-way couplings between pore fluid pressure and mechanical deformation, and (2) indirect couplings in terms of property changes, such as changes in mechanical stiffness, strength, and permeability. Direct pore-volume couplings have been studied in situ during borehole heating experiments in shale (or clay stone) formations at Mont Terri and Bure underground research laboratories in Switzerland and France. Typically, the temperature changes are accompanied with a rapid increase in pore pressure followed by a slower decrease towards initial (pre-heating) pore pressure. Coupled THM modeling of these heater tests shows that the pore pressure increases because the thermal expansion coefficient of the fluid is much higher than that of the porous clay stone. Such thermal pressurization induces fluid flow away from the pressurized area towards areas of lower pressure. The rate of pressure increase and magnitude of peak pressure depends on the rate of heating, pore-compressibility, and permeability of the shale. Modeling as well as laboratory experiments have shown that if the pore pressure increase is sufficiently large it could lead to fracturing of the shale or shear slip along pre-existing bedding planes. Another set of data and observations have been collected associated with studies related to concentrated heating and cooling of oil-shales and shale-gas formations. Heating may be used to enhance production from tight oil-shale, whereas thermal stimulation has been attempted for enhanced shale-gas extraction. Laboratory experiments on shale have shown that strength and elastic deformation modulus decreases with temperature while the rate creep deformations increase with temperature. Such temperature dependency also affects the well stability and zonal sealing across shale layers.

Thermal - Hydraulic Behavior of Unsaturated Bentonite and Sand-Bentonite Material as Seal for Nuclear Waste Repository: Numerical Simulation of Column Experiments

NASA Astrophysics Data System (ADS)

Ballarini, E.; Graupner, B.; Bauer, S.

2015-12-01

For deep geological repositories of high-level radioactive waste (HLRW), bentonite and sand bentonite mixtures are investigated as buffer materials to form a a sealing layer. This sealing layer surrounds the canisters and experiences an initial drying due to the heat produced by HLRW and a successive re-saturation with fluid from the host rock. These complex thermal, hydraulic and mechanical processes interact and were investigated in laboratory column experiments using MX-80 clay pellets as well as a mixture of 35% sand and 65% bentonite. The aim of this study is to both understand the individual processes taking place in the buffer materials and to identify the key physical parameters that determine the material behavior under heating and hydrating conditions. For this end, detailed and process-oriented numerical modelling was applied to the experiments, simulating heat transport, multiphase flow and mechanical effects from swelling. For both columns, the same set of parameters was assigned to the experimental set-up (i.e. insulation, heater and hydration system), while the parameters of the buffer material were adapted during model calibration. A good fit between model results and data was achieved for temperature, relative humidity, water intake and swelling pressure, thus explaining the material behavior. The key variables identified by the model are the permeability and relative permeability, the water retention curve and the thermal conductivity of the buffer material. The different hydraulic and thermal behavior of the two buffer materials observed in the laboratory observations was well reproduced by the numerical model.

Acoustic levitation technique for containerless processing at high temperatures in space

NASA Technical Reports Server (NTRS)

Rey, Charles A.; Merkley, Dennis R.; Hammarlund, Gregory R.; Danley, Thomas J.

1988-01-01

High temperature processing of a small specimen without a container has been demonstrated in a set of experiments using an acoustic levitation furnace in the microgravity of space. This processing technique includes the positioning, heating, melting, cooling, and solidification of a material supported without physical contact with container or other surface. The specimen is supported in a potential energy well, created by an acoustic field, which is sufficiently strong to position the specimen in the microgravity environment of space. This containerless processing apparatus has been successfully tested on the Space Shuttle during the STS-61A mission. In that experiment, three samples wer successfully levitated and processed at temperatures from 600 to 1500 C. Experiment data and results are presented.

Distortion of Digital Image Correlation (DIC) Displacements and Strains from Heat Waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, E. M. C.; Reu, P. L.

“Heat waves” is a colloquial term used to describe convective currents in air formed when different objects in an area are at different temperatures. In the context of Digital Image Correlation (DIC) and other optical-based image processing techniques, imaging an object of interest through heat waves can significantly distort the apparent location and shape of the object. We present that there are many potential heat sources in DIC experiments, including but not limited to lights, cameras, hot ovens, and sunlight, yet error caused by heat waves is often overlooked. This paper first briefly presents three practical situations in which heatmore » waves contributed significant error to DIC measurements to motivate the investigation of heat waves in more detail. Then the theoretical background of how light is refracted through heat waves is presented, and the effects of heat waves on displacements and strains computed from DIC are characterized in detail. Finally, different filtering methods are investigated to reduce the displacement and strain errors caused by imaging through heat waves. The overarching conclusions from this work are that errors caused by heat waves are significantly higher than typical noise floors for DIC measurements, and that the errors are difficult to filter because the temporal and spatial frequencies of the errors are in the same range as those of typical signals of interest. In conclusion, eliminating or mitigating the effects of heat sources in a DIC experiment is the best solution to minimizing errors caused by heat waves.« less

Distortion of Digital Image Correlation (DIC) Displacements and Strains from Heat Waves

DOE PAGES

Jones, E. M. C.; Reu, P. L.

2017-11-28

“Heat waves” is a colloquial term used to describe convective currents in air formed when different objects in an area are at different temperatures. In the context of Digital Image Correlation (DIC) and other optical-based image processing techniques, imaging an object of interest through heat waves can significantly distort the apparent location and shape of the object. We present that there are many potential heat sources in DIC experiments, including but not limited to lights, cameras, hot ovens, and sunlight, yet error caused by heat waves is often overlooked. This paper first briefly presents three practical situations in which heatmore » waves contributed significant error to DIC measurements to motivate the investigation of heat waves in more detail. Then the theoretical background of how light is refracted through heat waves is presented, and the effects of heat waves on displacements and strains computed from DIC are characterized in detail. Finally, different filtering methods are investigated to reduce the displacement and strain errors caused by imaging through heat waves. The overarching conclusions from this work are that errors caused by heat waves are significantly higher than typical noise floors for DIC measurements, and that the errors are difficult to filter because the temporal and spatial frequencies of the errors are in the same range as those of typical signals of interest. In conclusion, eliminating or mitigating the effects of heat sources in a DIC experiment is the best solution to minimizing errors caused by heat waves.« less

Long-lasting Science Returns from the Apollo Heat Flow Experiments

NASA Astrophysics Data System (ADS)

Nagihara, S.; Taylor, P. T.; Williams, D. R.; Zacny, K.; Hedlund, M.; Nakamura, Y.

2012-12-01

The Apollo astronauts deployed geothermal heat flow instruments at landing sites 15 and 17 as part of the Apollo Lunar Surface Experiments Packages (ALSEP) in July 1971 and December 1972, respectively. These instruments continuously transmitted data to the Earth until September 1977. Four decades later, the data from the two Apollo sites remain the only set of in-situ heat flow measurements obtained on an extra-terrestrial body. Researchers continue to extract additional knowledge from this dataset by utilizing new analytical techniques and by synthesizing it with data from more recent lunar orbital missions such as the Lunar Reconnaissance Orbiter. In addition, lessons learned from the Apollo experiments help contemporary researchers in designing heat flow instruments for future missions to the Moon and other planetary bodies. For example, the data from both Apollo sites showed gradual warming trends in the subsurface from 1971 to 1977. The cause of this warming has been debated in recent years. It may have resulted from fluctuation in insolation associated with the 18.6-year-cycle precession of the Moon, or sudden changes in surface thermal environment/properties resulting from the installation of the instruments and the astronauts' activities. These types of re-analyses of the Apollo data have lead a panel of scientists to recommend that a heat flow probe carried on a future lunar mission reach 3 m into the subsurface, ~0.6 m deeper than the depths reached by the Apollo 17 experiment. This presentation describes the authors' current efforts for (1) restoring a part of the Apollo heat flow data that were left unprocessed by the original investigators and (2) designing a compact heat flow instrument for future robotic missions to the Moon. First, at the conclusion of the ALSEP program in 1977, heat flow data obtained at the two Apollo sites after December 1974 were left unprocessed and not properly archived through NASA. In the following decades, heat flow data from January 1975 through February 1976, as well as the metadata necessary for processing the data (the data reduction algorithm, instrument calibration data, etc.), were somehow lost. In 2010, we located 450 original master archival tapes of unprocessed data from all the ALSEP instruments for a period of April through June 1975 at the Washington National Records Center. We are currently extracting the heat flow data packets from these tapes and processing them. Second, on future lunar missions, heat flow probes will likely be deployed by a network of small robotic landers, as recommended by the latest Decadal Survey of the National Academy of Science. In such a scenario, the heat flow probe must be a compact system, and that precludes use of heavy excavation equipment such as a rotary drill for reaching the 3-m target depth. The new heat flow system under development uses a pneumatically driven penetrator. It utilizes a stem that winds out of a reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab experiments have demonstrated its effectiveness in lunar vacuum.

Long-Lasting Science Returns from the Apollo Heat Flow Experiments

NASA Technical Reports Server (NTRS)

Nagihara, S.; Taylor, P. T.; Williams, D. R.; Zacny, K.; Hedlund, M.; Nakamura, Y.

2012-01-01

The Apollo astronauts deployed geothermal heat flow instruments at landing sites 15 and 17 as part of the Apollo Lunar Surface Experiments Packages (ALSEP) in July 1971 and December 1972, respectively. These instruments continuously transmitted data to the Earth until September 1977. Four decades later, the data from the two Apollo sites remain the only set of in-situ heat flow measurements obtained on an extra-terrestrial body. Researchers continue to extract additional knowledge from this dataset by utilizing new analytical techniques and by synthesizing it with data from more recent lunar orbital missions such as the Lunar Reconnaissance Orbiter. In addition, lessons learned from the Apollo experiments help contemporary researchers in designing heat flow instruments for future missions to the Moon and other planetary bodies. For example, the data from both Apollo sites showed gradual warming trends in the subsurface from 1971 to 1977. The cause of this warming has been debated in recent years. It may have resulted from fluctuation in insolation associated with the 18.6-year-cycle precession of the Moon, or sudden changes in surface thermal environment/properties resulting from the installation of the instruments and the astronauts' activities. These types of reanalyses of the Apollo data have lead a panel of scientists to recommend that a heat flow probe carried on a future lunar mission reach 3 m into the subsurface, approx 0.6 m deeper than the depths reached by the Apollo 17 experiment. This presentation describes the authors current efforts for (1) restoring a part of the Apollo heat flow data that were left unprocessed by the original investigators and (2) designing a compact heat flow instrument for future robotic missions to the Moon. First, at the conclusion of the ALSEP program in 1977, heat flow data obtained at the two Apollo sites after December 1974 were left unprocessed and not properly archived through NASA. In the following decades, heat flow data from January 1975 through February 1976, as well as the metadata necessary for processing the data (the data reduction algorithm, instrument calibration data, etc.), were somehow lost. In 2010, we located 450 original master archival tapes of unprocessed data from all the ALSEP instruments for a period of April through June 1975 at the Washington National Records Center. We are currently extracting the heat flow data packets from these tapes and processing them. Second, on future lunar missions, heat flow probes will likely be deployed by a network of small robotic landers, as recommended by the latest Decadal Survey of the National Academy of Science. In such a scenario, the heat flow probe must be a compact system, and that precludes use of heavy excavation equipment such as a rotary drill for reaching the 3-m target depth. The new heat flow system under development uses a pneumatically driven penetrator. It utilizes a stem that winds out of a reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab experiments have demonstrated its effectiveness in lunar vacuum.

3D Material Response Analysis of PICA Pyrolysis Experiments

NASA Technical Reports Server (NTRS)

Oliver, Brandon A.

2017-01-01

Primarily interested in improving ablation modeling for use in inverse reconstruction of flight environments on ablative heat shields. Ablation model is essentially a component of the heat flux sensor, so model uncertainties lead to measurement uncertainties. Non-equilibrium processes have been known to be significant in low density ablators for a long time, but increased accuracy requirements of the reconstruction process necessitates incorporating this physical effect. Attempting to develop a pyrolysis model for implementation in material response based on the PICA data produced by Bessire and Minton. Pyrolysis gas species molar yields as a function of temperature and heating rate. Several problems encountered while trying to fit Arrhenius models to the data led to further investigation of the experimental setup.

Three phase heat and mass transfer model for unsaturated soil freezing process: Part 2 - model validation

NASA Astrophysics Data System (ADS)

Zhang, Yaning; Xu, Fei; Li, Bingxi; Kim, Yong-Song; Zhao, Wenke; Xie, Gongnan; Fu, Zhongbin

2018-04-01

This study aims to validate the three-phase heat and mass transfer model developed in the first part (Three phase heat and mass transfer model for unsaturated soil freezing process: Part 1 - model development). Experimental results from studies and experiments were used for the validation. The results showed that the correlation coefficients for the simulated and experimental water contents at different soil depths were between 0.83 and 0.92. The correlation coefficients for the simulated and experimental liquid water contents at different soil temperatures were between 0.95 and 0.99. With these high accuracies, the developed model can be well used to predict the water contents at different soil depths and temperatures.

Transient nucleate pool boiling in microgravity: Some initial results

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.; Lee, H. S.; Ervin, J. S.

1994-01-01

Variable gravity provides an opportunity to test the understanding of phenomena which are considered to depend on buoyancy, such as nucleate pool boiling. The active fundamental research in nucleate boiling has sought to determine the mechanisms or physical processes responsible for its high effectiveness, manifested by the high heat flux levels possible with relatively low temperature differences. Earlier research on nucleate pool boiling at high gravity levels under steady conditions demonstrated quantitatively that the heat transfer is degraded as the buoyancy normal to the heater surfaced increases. Correspondingly, it was later shown, qualitatively for short periods of time only, that nucleate boiling heat transfer is enhanced as the buoyancy normal to the heater surface is reduced. It can be deduced that nucleate pool boiling can be sustained as a quasi-steady process provided that some means is available to remove the vapor generated from the immediate vicinity of the heater surface. One of the objectives of the research, the initial results of which are presented here, is to quantify the heat transfer associated with boiling in microgravity. Some quantitative results of nucleate pool boiling in high quality microgravity (a/g approximately 10(exp -5)) of 5s duration, obtained in an evacuated drop tower, are presented here. These experiments were conducted as precursors of longer term space experiments. A transient heating technique is used, in which the heater surface is a transparent gold film sputtered on a qua rtz substrate, simultaneously providing the mean surface temperature from resistance thermometry and viewing of the boiling process both from beneath and across the surface. The measurement of the transient mean heater surface temperature permits the computation, by numerical means, of the transient mean heat transfer coefficient. The preliminary data obtained demonstrates that a quasi-steady boiling process can occur in microgravity if the bulk liquid subcooling is sufficiently high and if the imposed heat flux is sufficiently low. This is attributed to suface tension effects at the liquid-vapor-solid junction causing rewetting to take place, sustaining the nucleate boiling. Otherwise, dryout at the heater surface will occur, as observed.

Listeria Infection (Listeriosis)

MedlinePlus

... made with unpasteurized milk or poorly heated hot dogs or deli meats. If you experience a high ... Certain processed foods — such as soft cheeses, hot dogs and deli meats that have been contaminated after ...

The effects of cold rolling and the subsequent heat treatments on the shape memory and the superelasticity characteristics of Cu73Al16Mn11 shape memory alloy

NASA Astrophysics Data System (ADS)

Babacan, N.; Ma, J.; Turkbas, O. S.; Karaman, I.; Kockar, B.

2018-01-01

In the present study, the effect of thermo-mechanical treatments on the shape memory and the superelastic characteristics of Cu73Al16Mn11 (at%) shape memory alloy were investigated. 10%, 50% and 70% cold rolling and subsequent heat treatment processes were conducted to achieve strengthening via grain size refinement. 70% grain size reduction compared to the homogenized condition was obtained using 70% cold rolling and subsequent recrystallization heat treatment technique. Moreover, 10% cold rolling was applied to homogenized specimen to reveal the influence of the low percentage cold rolling reduction with no heat treatment on shape memory properties of Cu73Al16Mn11 (at%) alloy. Stress free transformation temperatures, monotonic tension and superelasticity behaviors of these samples were compared with those of the as-aged sample. Isobaric heating-cooling experiments were also conducted to see the dimensional stability of the samples as a function of applied stress. The 70% grain-refined sample exhibited better dimensional stability showing reduced residual strain levels upon thermal cycling under constant stress compared with the as-aged material. However, no improvement was achieved with grain size reduction in the superelasticity experiments. This distinctive observation was attributed to the difference in the magnitude of the stress levels achieved during two different types of experiments which were the isobaric heating-cooling and superelasticity tests. Intergranular fracture due to the stress concentration overcame the strengthening effect via grain refinement in the superelasticity tests at higher stress values. On the other hand, the strength of the material and resistance of material against plastic deformation upon phase transformation were increased as a result of the grain refinement at lower stress values in the isobaric heating-cooling experiments.

The Design, Fabrication and Characterization of a Transparent Atom Chip

PubMed Central

Chuang, Ho-Chiao; Huang, Chia-Shiuan; Chen, Hung-Pin; Huang, Chi-Sheng; Lin, Yu-Hsin

2014-01-01

This study describes the design and fabrication of transparent atom chips for atomic physics experiments. A fabrication process was developed to define the wire patterns on a transparent glass substrate to create the desired magnetic field for atom trapping experiments. An area on the chip was reserved for the optical access, so that the laser light can penetrate directly through the glass substrate for the laser cooling process. Furthermore, since the thermal conductivity of the glass substrate is poorer than other common materials for atom chip substrate, for example silicon, silicon carbide, aluminum nitride. Thus, heat dissipation copper blocks are designed on the front and back of the glass substrate to improve the electrical current conduction. The testing results showed that a maximum burnout current of 2 A was measured from the wire pattern (with a width of 100 μm and a height of 20 μm) without any heat dissipation design and it can increase to 2.5 A with a heat dissipation design on the front side of the atom chips. Therefore, heat dissipation copper blocks were designed and fabricated on the back of the glass substrate just under the wire patterns which increases the maximum burnout current to 4.5 A. Moreover, a maximum burnout current of 6 A was achieved when the entire backside glass substrate was recessed and a thicker copper block was electroplated, which meets most requirements of atomic physics experiments. PMID:24922456

A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

NASA Astrophysics Data System (ADS)

Jakkareddy, Pradeep S.; Balaji, C.

2017-02-01

This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

Vertical structure and physical processes of the Madden-Julian Oscillation: Biases and uncertainties at short range

NASA Astrophysics Data System (ADS)

Xavier, Prince K.; Petch, Jon C.; Klingaman, Nicholas P.; Woolnough, Steve J.; Jiang, Xianan; Waliser, Duane E.; Caian, Mihaela; Cole, Jason; Hagos, Samson M.; Hannay, Cecile; Kim, Daehyun; Miyakawa, Tomoki; Pritchard, Michael S.; Roehrig, Romain; Shindo, Eiki; Vitart, Frederic; Wang, Hailan

2015-05-01

An analysis of diabatic heating and moistening processes from 12 to 36 h lead time forecasts from 12 Global Circulation Models are presented as part of the "Vertical structure and physical processes of the Madden-Julian Oscillation (MJO)" project. A lead time of 12-36 h is chosen to constrain the large-scale dynamics and thermodynamics to be close to observations while avoiding being too close to the initial spin-up of the models as they adjust to being driven from the Years of Tropical Convection (YOTC) analysis. A comparison of the vertical velocity and rainfall with the observations and YOTC analysis suggests that the phases of convection associated with the MJO are constrained in most models at this lead time although the rainfall in the suppressed phase is typically overestimated. Although the large-scale dynamics is reasonably constrained, moistening and heating profiles have large intermodel spread. In particular, there are large spreads in convective heating and moistening at midlevels during the transition to active convection. Radiative heating and cloud parameters have the largest relative spread across models at upper levels during the active phase. A detailed analysis of time step behavior shows that some models show strong intermittency in rainfall and differences in the precipitation and dynamics relationship between models. The wealth of model outputs archived during this project is a very valuable resource for model developers beyond the study of the MJO. In addition, the findings of this study can inform the design of process model experiments, and inform the priorities for field experiments and future observing systems.

Numerical simulations of thermal conductivity in dissipative two-dimensional Yukawa systems.

PubMed

Khrustalyov, Yu V; Vaulina, O S

2012-04-01

Numerical data on the heat transfer constants in two-dimensional Yukawa systems were obtained. Numerical study of the thermal conductivity and diffusivity was carried out for the equilibrium systems with parameters close to conditions of laboratory experiments with dusty plasma. For calculations of heat transfer constants the Green-Kubo formulas were used. The influence of dissipation (friction) on the heat transfer processes in nonideal systems was investigated. The approximation of the coefficient of thermal conductivity is proposed. Comparison of the obtained results to the existing experimental and numerical data is discussed.

Brazing of refractory, superalloy, and composite materials for Space Shuttle applications.

NASA Technical Reports Server (NTRS)

Beuyukian, C. S.

1972-01-01

Research work concerning the metallic portion of the shuttle-orbiter heat shield (expected to experience temperatures up to 2500 F) is described. The five metals being evaluated are TD-Ni-Cr, Cb-C129Y, Cb752, Hayes 188, and Inconel 625. Brazing techniques whereby pairs of these materials are joined into thin-membered assemblies for heat shield applications are described. Results obtained with the vacuum-furnace brazing process are examined. In addition, the use of brazed aluminum-boron metal-matrix-contoured composite structures for heat shield applications is evaluated.

Optimal fusion offset in splicing photonic crystal fibers

NASA Astrophysics Data System (ADS)

Jin, Wa; Bi, Weihong; Fu, Guangwei

2013-08-01

Heat transfer is very complicate in fusion splicing process of photonic crystal fibers (PCFs) due to different structures and sizes of air hole, which requires different fusion splicing power and offsets of heat source. Based on the heat transfer characteristics, this paper focus on the optimal splicing offset splicing the single mode fiber and PCFs with a CO2 laser irradiation. The theory and experiments both show that the research results can effectively calculate the optimal fusion splicing offset and guide the practical splicing between PCFs and SMFs.

[Extraction method suitable for detection of unheated crustaceans including cephalothorax by ELISA].

PubMed

Shibahara, Yusuke; Yamada, Itta; Uesaka, Yoshihiko; Uneo, Noriko; Abe, Akihisa; Ohashi, Eiji; Shiomi, Kazuo

2009-08-01

When unheated whole samples of crustaceans (shrimp, prawn and crab) were analyzed with our ELISA kit (FA test EIA-Crustacean 'Nissui') using anti-tropomyosin antibodies, a remarkable reduction in reactivity was recognized. This reduction in activity was found to be due to the digestion of tropomyosin during the extraction process by proteases contained in cephalothorax. To avoid the digestion of tropomyosin by proteases, we developed an extraction method (heating method) suitable for the detection of tropomyosin in unheated crustaceans including cephalothorax. Experiments with unheated whole samples of various species of crustaceans confirmed that the heating method greatly improved the low reactivity in the standard method; the heating method gave extraction efficiencies of as high as 93-107%. Various processed crustaceans with cephalothorax, such as dry products (unheated or weakly heated products) and pickles in soy sauce (unheated products), that showed low reactivity with the standard method were confirmed to give superior results with the heating method. These results indicated that the developed heating method is suitable for detecting unheated crustaceans with cephalothorax by means of the ELISA kit.

Influence of Strain Rate on Heat Release under Quasi-Static Stretching of Metals. Experiment

NASA Astrophysics Data System (ADS)

Zimin, B. A.; Sventitskaya, V. E.; Smirnov, I. V.; Sud'enkov, Yu. V.

2018-04-01

The paper presents the results of experimental studies of energy dissipation during a quasi-static stretching of metals and alloys at room temperature. The strain rates varied in the range of 10-3-10-2 s-1. Samples of M1 copper, AZ31B magnesium alloy, BT6 titanium, 12Cr18Ni10Ti steel, and D16AM aluminum alloy were analyzed. The experimental results demonstrated a significant dependence of the heat release on the strain rate in the absence of its influence on stress-strain diagrams for all the metals studied in this range of strain rates. The correlation of the changes in the character of heat release with the processes of structural transformations at various stages of plastic flow is shown on the qualitative level. A difference in the nature of the processes of heat release in materials with different ratios of the plasticity and strength is noted.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anameric, B.; Kawatra, S.K.

The pig iron nugget process is gaining in importance as an alternative to the traditional blast furnace. Throughout the process, self-reducing-fluxing dried greenballs composed of iron ore concentrate, reducing-carburizing agent (coal), flux (limestone) and binder (bentonite) are heat-treated. During the heat treatment, dried greenballs are first transformed into direct reduced iron (DRI), then to transition direct reduced iron (TDRI) and finally to pig iron nuggets. The furnace temperature and/or residence time and the corresponding levels of carburization, reduction and metallization dictate these transformations. This study involved the determination of threshold furnace temperatures and residence times for completion of all ofmore » the transformation reactions and pig iron nugget production. The experiments involved the heat treatment of self-reducing-fluxing dried greenballs at various furnace temperatures and residence times. The products of these heat treatments were identified by utilizing optical microscopy, apparent density and microhardness measurements.« less

Fault-Tolerant Heat Exchanger

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Crowley, Christopher J.

2005-01-01

A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

Vapor Compression and Thermoelectric Heat Pumps for a Cascade Distillation Subsystem: Design and Experiment

NASA Technical Reports Server (NTRS)

Erickson, Lisa R.; Ungar, Eugene K.

2012-01-01

Humans on a spacecraft require significant amounts of water for drinking, food, hydration, and hygiene. Maximizing the reuse of wastewater while minimizing the use of consumables is critical for long duration space exploration. One of the more promising consumable-free methods of reclaiming wastewater is the distillation/condensation process used in the Cascade Distillation Subsystem (CDS). The CDS heats wastewater to the point of vaporization then condenses and cools the resulting water vapor. The CDS wastewater flow requires heating for evaporation and the product water flow requires cooling for condensation. Performing the heating and cooling processes separately would require two separate units, each of which would demand large amounts of electrical power. Mass, volume, and power efficiencies can be obtained by heating the wastewater and cooling the condensate in a single heat pump unit. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the CDS system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump analysis and performance tests are provided. The mass, volume, and power requirement for each heat pump option is compared and the advantages and disadvantages of each system are listed.

The Adiabatic Expansion of Gases and the Determination of Heat Capacity Ratios: A Physical Chemistry Experiment.

ERIC Educational Resources Information Center

Moore, William M.

1984-01-01

Describes the procedures and equipment for an experiment on the adiabatic expansion of gases suitable for demonstration and discussion in the physical chemical laboratory. The expansion produced shows how the process can change temperature and still return to a different location on an isotherm. (JN)

Physical and chemical behavior of flowing endothermic jet fuels

NASA Astrophysics Data System (ADS)

Ward, Thomas Arthur

Hydrocarbon fuels have been used as cooling media for aircraft jet engines for decades. However, modern aircraft engines are reaching a practical heat transfer limit beyond which the convective heat transfer provided by fuels is no longer adequate. One solution is to use an endothermic fuel that absorbs heat through a series of pyrolytic chemical reactions. However, many of the physical and chemical processes involved in endothermic fuel degradation are not well understood. The purpose of this dissertation is to study different characteristics of endothermic fuels using experiments and computational models. In the first section, data from three flow experiments using heated Jet-A fuel and additives were analyzed (with the aid of CFD calculations) to study the effects of treated surfaces on surface deposition. Surface deposition is the primary impediment in creating an operational endothermic fuel heat exchanger system, because deposits can obstruct fuel pathways causing a catastrophic system failure. As heated fuel flows through a fuel system, trace species within the fuel react with dissolved O2 to form surface deposits. At relatively higher fuel temperatures, the dissolved O2 is depleted, and pyrolytic chemistry becomes dominant (at temperatures greater than ˜500 °C). In the first experiment, the dissolved O2 consumption of heated fuel was measured on different surface types over a range of temperatures. It is found that use of treated tubes significantly delays oxidation of the fuel. In the second experiment, the treated length of tubing was progressively increased, which varied the characteristics of the thermal-oxidative deposits formed. In the third experiment, pyrolytic surface deposition in either fully treated or untreated tubes is studied. It is found that the treated surface significantly reduced the formation of surface deposits for both thermal oxidative and pyrolytic degradation mechanisms. Moreover, it is found that the chemical reactions resulting in pyrolytic deposition on the untreated surface are more sensitive to pressure level than those causing pyrolytic deposition on the treated surface. The second section describes the development of a two-dimensional computational model of the heat and mass transport associated with a flowing fuel using a unique global chemical kinetics model. This model calculates the changing flow properties of a supercritical reacting fuel by use of experimentally derived proportional product distributions. The third section studies the effects of pressure on flowing; mildly-cracked, supercritical n-decane. The experimental results are studied with the aid of the computational model described in section 2, expanded to deal with variable pressures. The experiments indicate that increasing pressure enhances the processes in which n-decane converts to (C5--C9) n-alkane products instead of decomposing into lower molecular weight products (C1--C4): Increasing pressure also increases the overall conversion rate of supercritical n-decane flowing through a reactor. Computational modeling of the experiment shows how the flow properties are influenced by pressure. (Abstract shortened by UMI.)

The bromodomain protein BRD4 regulates splicing during heat shock

PubMed Central

Hussong, Michelle; Kaehler, Christian; Kerick, Martin; Grimm, Christina; Franz, Alexandra; Timmermann, Bernd; Welzel, Franziska; Isensee, Jörg; Hucho, Tim; Krobitsch, Sylvia; Schweiger, Michal R.

2017-01-01

The cellular response to heat stress is an ancient and evolutionarily highly conserved defence mechanism characterised by the transcriptional up-regulation of cyto-protective genes and a partial inhibition of splicing. These features closely resemble the proteotoxic stress response during tumor development. The bromodomain protein BRD4 has been identified as an integral member of the oxidative stress as well as of the inflammatory response, mainly due to its role in the transcriptional regulation process. In addition, there are also several lines of evidence implicating BRD4 in the splicing process. Using RNA-sequencing we found a significant increase in splicing inhibition, in particular intron retentions (IR), following heat treatment in BRD4-depleted cells. This leads to a decrease of mRNA abundancy of the affected transcripts, most likely due to premature termination codons. Subsequent experiments revealed that BRD4 interacts with the heat shock factor 1 (HSF1) such that under heat stress BRD4 is recruited to nuclear stress bodies and non-coding SatIII RNA transcripts are up-regulated. These findings implicate BRD4 as an important regulator of splicing during heat stress. Our data which links BRD4 to the stress induced splicing process may provide novel mechanisms of BRD4 inhibitors in regard to anti-cancer therapies. PMID:27536004

Mixing in heterogeneous internally-heated convection

NASA Astrophysics Data System (ADS)

Limare, A.; Kaminski, E. C.; Jaupart, C. P.; Farnetani, C. G.; Fourel, L.; Froment, M.

2017-12-01

Past laboratory experiments of thermo chemical convection have dealt with systems involving fluids with different intrinsic densities and viscosities in a Rayleigh-Bénard setup. Although these experiments have greatly improved our understanding of the Earth's mantle dynamics, they neglect a fundamental component of planetary convection: internal heat sources. We have developed a microwave-based method in order to study convection and mixing in systems involving two layers of fluid with different densities, viscosities, and internal heat production rates. Our innovative laboratory experiments are appropriate for the early Earth, when the lowermost mantle was likely enriched in incompatible and heat producing elements and when the heat flux from the core probably accounted for a small fraction of the mantle heat budget. They are also relevant to the present-day mantle if one considers that radioactive decay and secular cooling contribute both to internal heating. Our goal is to quantify how two fluid layers mix, which is still very difficult to resolve accurately in 3-D numerical calculations. Viscosities and microwave absorptions are tuned to achieve high values of the Rayleigh-Roberts and Prandtl numbers relevant for planetary convection. We start from a stably stratified system where the lower layer has higher internal heat production and density than the upper layer. Due to mixing, the amount of enriched material gradually decreases to zero over a finite time called the lifetime. Based on more than 30 experiments, we have derived a scaling law that relates the lifetime of an enriched reservoir to the layer thickness ratio, a, to the density and viscosity contrasts between the two layers, and to their two different internal heating rates in the form of an enrichment factor beta=1+2*a*H1/H, where H1 is the heating rate of the lower fluid and H is the average heating rate. We find that the lifetime of the lower enriched reservoir varies as beta**(-7/3) in the low viscosity contrast limit, and as beta**(-4/3) in the large viscosity contrast limit. Our state-of-the-art experimental technique thus provides insights on chemical differentiation processes and on the evolution of mantle heterogeneities on both short and long time-scales.

Influences of elevated heating effect by the Himalaya on the changes in Asian summer monsoon

NASA Astrophysics Data System (ADS)

He, Bian

2017-05-01

Based on a series of topographical and thermal sensitivity experiments, the physical processes on the changes of Asian summer monsoon caused by the Himalaya elevated heating were investigated. Six different Himalaya-Iranian Plateau mountain heights were used: 0, 20, 40, 60, 80, and 100 % in the first group (called HIM). The no sensible heating experiments (called HIM_NS) were also performed with the same six mountain heights, but the surface sensible heating was not allowed to heat the atmosphere. The results indicate that the elevated heating effect of the Himalaya gradually intensified when the Himalaya uplifts. The establishment of SASM over the South Asian land which is characterized by the strong precipitation over south slope of the Tibetan Plateau and the huge warm anticyclone in the upper troposphere are in proportion to the elevated heating effect of the Himalaya. Further analysis suggests that the surface heat fluxes over the Himalaya keep almost unchanged during the uplifting, but the lifted condensation level reduces gradually over the regions where the mountain uplifts. The condensation moisturing increases correspondingly and leads to the increase of latent heating in the upper troposphere. Therefore, the positive feedback between the moist convection over the south slope of the Himalaya and monsoon circulation over Indian subcontinent forms and the successive precipitation over the South Asian land is maintained.

CFD Analysis of nanofluid forced convection heat transport in laminar flow through a compact pipe

NASA Astrophysics Data System (ADS)

Yu, Kitae; Park, Cheol; Kim, Sedon; Song, Heegun; Jeong, Hyomin

2017-08-01

In the present paper, developing laminar forced convection flows were numerically investigated by using water-Al2O3 nano-fluid through a circular compact pipe which has 4.5mm diameter. Each model has a steady state and uniform heat flux (UHF) at the wall. The whole numerical experiments were processed under the Re = 1050 and the nano-fluid models were made by the Alumina volume fraction. A single-phase fluid models were defined through nano-fluid physical and thermal properties calculations, Two-phase model(mixture granular model) were processed in 100nm diameter. The results show that Nusselt number and heat transfer rate are improved as the Al2O3 volume fraction increased. All of the numerical flow simulations are processed by the FLUENT. The results show the increment of thermal transfer from the volume fraction concentration.

Light Microscopy Module: On-Orbit Microscope Planned for the Fluids Integrated Rack on the International Space Station

NASA Technical Reports Server (NTRS)

Motil, Susan M.

2002-01-01

The Light Microscopy Module (LMM) is planned as a remotely controllable, automated, on-orbit facility, allowing flexible scheduling and control of physical science and biological science experiments within the Fluids Integrated Rack (FIR) on the International Space Station. Initially four fluid physics experiments in the FIR will use the LMM the Constrained Vapor Bubble, the Physics of Hard Spheres Experiment-2, Physics of Colloids in Space-2, and Low Volume Fraction Entropically Driven Colloidal Assembly. The first experiment will investigate heat conductance in microgravity as a function of liquid volume and heat flow rate to determine, in detail, the transport process characteristics in a curved liquid film. The other three experiments will investigate various complementary aspects of the nucleation, growth, structure, and properties of colloidal crystals in microgravity and the effects of micromanipulation upon their properties.

A source mechanism producing HF-induced plasma lines (HFPLS) with up-shifted frequencies

NASA Technical Reports Server (NTRS)

Kuo, S. P.; Lee, M. C.

1992-01-01

Attention is given to a nonlinear scattering process analyzed as a source mechanism producing the frequency up-shifted HFPLs observed in the Arecibo ionospheric heating experiments. A physical picture is offered to explain how Langmuir waves with frequencies greater than the HF heater wave frequency can be produced in the heating experiments and be detected by incoherent radars as frequency up-shifted HFPLs. Since the considered scattering process occurs in a region near the reflection height, it explains why the frequency up-shifted HFPLs should originate from the altitude near the reflection height as observed. The theory also shows that the amount of frequency up-shift is inversely proportional to the frequency of the HF heater and increases linearly with the electron temperature. The quantitative analysis of the theory shows a good agreement with the experimental results.

Numerical Simulation of Thermal Performance of Glass-Fibre-Reinforced Polymer

NASA Astrophysics Data System (ADS)

Zhao, Yuchao; Jiang, Xu; Zhang, Qilin; Wang, Qi

2017-10-01

Glass-Fibre-Reinforced Polymer (GFRP), as a developing construction material, has a rapidly increasing application in civil engineering especially bridge engineering area these years, mainly used as decorating materials and reinforcing bars for now. Compared with traditional construction material, these kinds of composite material have obvious advantages such as high strength, low density, resistance to corrosion and ease of processing. There are different processing methods to form members, such as pultrusion and resin transfer moulding (RTM) methods, which process into desired shape directly through raw material; meanwhile, GFRP, as a polymer composite, possesses several particular physical and mechanical properties, and the thermal property is one of them. The matrix material, polymer, performs special after heated and endue these composite material a potential hot processing property, but also a poor fire resistance. This paper focuses on thermal performance of GFRP as panels and corresponding researches are conducted. First, dynamic thermomechanical analysis (DMA) experiment is conducted to obtain the glass transition temperature (Tg) of the object GFRP, and the curve of bending elastic modulus with temperature is calculated according to the experimental data. Then compute and estimate the values of other various thermal parameters through DMA experiment and other literatures, and conduct numerical simulation under two condition respectively: (1) the heat transfer process of GFRP panel in which the panel would be heated directly on the surface above Tg, and the hot processing under this temperature field; (2) physical and mechanical performance of GFRP panel under fire condition. Condition (1) is mainly used to guide the development of high temperature processing equipment, and condition (2) indicates that GFRP’s performance under fire is unsatisfactory, measures must be taken when being adopted. Since composite materials’ properties differ from each other and their high temperature parameters can’t be obtained through common methods, some parameters are estimated, the simulation is to guide the actual high temperature experiment, and the parameters will also be adjusted by then.

Some Considerations Relating to Combustion in Rocket Motors

DTIC Science & Technology

1950-03-01

evaporation and chemical reaction. Even the separate processes of heat and mass transfer under varying conditions are too complex for adequate theoretical...treatment although with the aid of dimensional analysis and experiment useful relationships for the heat transfer to spheres and for the evaporation of...if they do not evaporate sufficiently rapidly they may be carriod out of the rocket in the gas stream with a consequent loss in performance. 4

Experimental Studies of the Aerothermal Characteristics of the Project Orion CEV heat Shield in High Speed Transitional and Turbulent Flows

NASA Technical Reports Server (NTRS)

Wadhams, T.P.; MacLean, M.; Holden, M.S.; Cassady, A.M.

2009-01-01

An experimental program has been completed by CUBRC exploring laminar, transitional, and turbulent flows over a 7.0% scale model of the Project ORION CEV geometry. This program was executed primarily to answer questions concerning the increase in heat transfer on the windward, or "hot shoulder" of the CEV heat shield from laminar to turbulent flow. To answer these questions CUBRC constructed and instrumented a 14.0 inch diameter Project ORION CEV model and ran a range of Reynolds numbers based on diameter from 1.0 to over 40 million at a Mach number of 8.0. These Reynolds numbers were selected to cover laminar to turbulent heating data on the "hot shoulder". Data obtained during these runs will be used to guide design decisions as they apply to heat shield thickness and extent. Several experiments at higher enthalpies were achieved to obtain data for code validation with real gas effects and transition. CUBRC also performed computation studies of these experiments to aid in the data reduction process and study turbulence modeling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Wei; Faculty of Science, Kunming University of Science and Technology, Kunming 650093; Peng Jinhui

Experiments to prepare activated carbon by microwave heating indicated that microwave energy can decrease reaction temperature, save the energy and shorten processing time remarkably compared to conventional heating, owing to its internal and volumetric heating effects. The above results were based on the laboratory-scale experiments. It is desirable to develop a pilot-scale microwave heating equipment and investigate the parameters with the aim of technological industrialization. In the present study, the components and features of the self-invented equipment were introduced. The temperature rise curves of the chars were obtained. Iodine numbers of the activated carbons all exceed the state standard ofmore » China under the following conditions: 25 kg/h charging rate, 0.42 rev/min turning rate of ceramic tube, flow rate of steam at pressure of 0.01 MPa and 40 kW microwave heating power after 60 kW pre-activation for 30 min. Pore structure of the sample obtained at a time point of 46 h, which contained BET surface area, and pore size distributions of micropores and total pores, was tested by nitrogen adsorption at 77 K.« less

Pollen germination and in vivo fertilization in response to high-temperature during flowering in hybrid and inbred rice.

PubMed

Shi, Wanju; Li, Xiang; Schmidt, Ralf C; Struik, Paul C; Yin, Xinyou; Jagadish, S V Krishna

2018-01-15

High-temperature during flowering in rice causes spikelet sterility and is a major threat to rice productivity in tropical and subtropical regions, where hybrid rice development is increasingly contributing to sustain food security. However, the sensitivity of hybrids to increasing temperature and physiological responses in terms of dynamic fertilization processes is unknown. To address these questions, several promising hybrids and inbreds were exposed to control temperature and high day-time temperature (HDT) in Experiment 1, and hybrids having contrasting heat tolerance were selected for Experiment 2 for further physiological investigation under HDT and high-night-time-temperature treatments. The day-time temperature played a dominant role in determining spikelet fertility compared with the night-time temperature. HDT significantly induced spikelet sterility in tested hybrids, and hybrids had higher heat susceptibility than the high-yielding inbred varieties. Poor pollen germination was strongly associated with sterility under high-temperature. Our novel observations capturing the series of dynamic fertilization processes demonstrated that pollen tubes not reaching the viable embryo sac was the major cause for spikelet sterility under heat exposure. Our findings highlight the urgent need to improve heat tolerance in hybrids and incorporating early-morning flowering as a promising trait for mitigating HDT stress impact at flowering. © 2018 John Wiley & Sons Ltd.

A composite model for a class of electric-discharge shock tubes

NASA Technical Reports Server (NTRS)

Elkins, R. T.; Baganoff, D.

1973-01-01

A gasdynamic model is presented and analyzed for a class of shock tubes that utilize both Joule heating and electromagnetic forces to produce high-speed shock waves. The model consists of several stages of acceleration in which acceleration to sonic conditions is achieved principally through heating, and further acceleration of the supersonic flow is obtained principally through use of electromagnetic forces. The utility of the model results from the fact that it predicts a quasi-steady flow process, mathematical analysis is straightforward, and it is even possible to remove one or more component stages and still have the model related to a possible shock-tube flow. Initial experiments have been performed where the electrical discharge configuration and current level were such that Joule heating was the dominant form of energy addition present. These experiments indicate that the predictions of the model dealing with heat addition correspond quite closely to reality. The experimental data together with the theory show that heat addition to the flowing driver gas after diaphragm rupture (approach used in the model) is much more effective in producing high-speed shock waves than heating the gas in the driver before diaphragm rupture, as in the case of the arc-driven shock tube.

Bulk water freezing dynamics on superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

2017-01-01

In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm < Lc < 6 mm) using carefully designed freezing experiments in a temperature-controlled, zero-humidity environment on thin water slabs. To probe the effect of surface wettability, we investigated the total time for room temperature water to completely freeze into ice on superhydrophilic ( θaapp→ 0°), hydrophilic (0° < θa < 90°), hydrophobic (90° < θa < 125°), and superhydrophobic ( θaapp→ 180°) surfaces. Our results show that at macroscopic length scales, heat conduction through the bulk water/ice layer dominates the freezing process when compared to heat conduction through the functional coatings or nanoscale gaps at the superhydrophobic substrate-water/ice interface. In order to verify our findings, and to determine when the surface structure thermal resistance approaches the water/ice resistance, we fabricated and tested the additional substrates coated with commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

Agile green process design for the intensified Kolbe-Schmitt synthesis by accompanying (simplified) life cycle assessment.

PubMed

Kressirer, Sabine; Kralisch, Dana; Stark, Annegret; Krtschil, Ulrich; Hessel, Volker

2013-05-21

In order to investigate the potential for process intensification, various reaction conditions were applied to the Kolbe-Schmitt synthesis starting from resorcinol. Different CO₂ precursors such as aqueous potassium hydrogencarbonate, hydrogencarbonate-based ionic liquids, DIMCARB, or sc-CO₂, the application of microwave irradiation for fast volumetric heating of the reaction mixture, and the effect of harsh reaction conditions were investigated. The experiments, carried out in conventional batch-wise as well as in continuously operated microstructured reactors, aimed at the development of an environmentally benign process for the preparation of 2,4-dihydroxybenzoic acid. To provide decision support toward a green process design, a research-accompanying simplified life cycle assessment (SLCA) was performed throughout the whole investigation. Following this approach, it was found that convective heating methods such as oil bath or electrical heating were more beneficial than the application of microwave irradiation. Furthermore, the consideration of workup procedures was crucial for a holistic view on the environmental burdens.

Model Stirrer Based on a Multi-Material Turntable for Microwave Processing Materials

PubMed Central

Ye, Jinghua; Hong, Tao; Wu, Yuanyuan; Wu, Li; Liao, Yinhong; Zhu, Huacheng; Yang, Yang; Huang, Kama

2017-01-01

Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE) and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation. During the heating process, the processed material is placed on a fixed Teflon bracket which covers the constantly rotating turntable. Experiments are conducted to measure the surface and point temperatures using an infrared thermal imaging camera and optical fibers. Simulated results are compared qualitatively with the measured ones, which verifies the simulated models. Compared with the turntables consisting of a single material, a 26%–47% increase in temperature uniformity from adapting the multi-material turntable can be observed for the microwave-processed materials. PMID:28772457

Exploration of photosensitive polyimide as the modification layer in thin film microcircuit

NASA Astrophysics Data System (ADS)

Liu, Lily; Song, Changbin; Xue, Bin; Li, Jing; Wang, Junxi; Li, Jinmin

2018-02-01

Positive type photosensitive polyimide is used as the modification layer in the thin film transistors production process. The photosensitive polyimide is not only used as the second insulating layer, it can also be used instead of a mask because of the photosensitivity. A suitable curing condition can help photosensitive polyimide form the high performance polyimide with orderly texture inside, and the performance of imidization depends on the precise control of temperature, time, and heat control during the curing process. Therefore, experiments of different stepped up heating tests are made, and the ability of protecting silicon dioxide is analyzed.

Results from a lab study of melting sea ice

NASA Astrophysics Data System (ADS)

Wiese, M.; Griewank, P.; Notz, D.

2012-04-01

Sea-ice melting is a complex process which is not fully understood yet. In order to study sea-ice melt in detail we perform lab experiments in an approximately 2x0.7x1.2 m large tank in a cold room. We grow sea ice with different salinities at least 10 cm thick. Then we let the ice melt at different air temperatures and oceanic heat fluxes. During the melt period, we measure the evolution of ice thickness, internal temperature, salinity and surface temperature. We will present results from roughly five months of experiments. Topics will include the influence of bulk salinity on melt rates and the surface temperature. The effects of flushing on the salinity evolution and detailed thermal profiles will also be included. To investigate these processes we focus on the energy budget and the salinity evolution. These topics are linked since the thermodynamic properties of sea ice (heat capacity, heat conductivity and latent heat of fusion) are very sensitive to salinity variations. For example the heat capacity of sea ice increases greatly as the temperature approaches the melting point. This increase results in non-linear temperature profiles and enhances heat conduction into the ice. The salinity evolution during the growth phase has been investigated and measured in multiple studies over the last decades. In contrast there are no detailed lab measurements of melting ice available to quantify the effects of flushing melt water and ponding. This is partially due to the fact that the heterogeneity of melting sea ice makes it much more difficult to measure representative values.

Pretest parametric calculations for the heated pillar experiment in the WIPP In-Situ Experimental Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branstetter, L.J.

Results are presented for a pretest parametric study of several configurations and heat loads for the heated pillar experiment (Room H) in the Waste Isolation Pilot Plant (WIPP) In Situ Experimental Area. The purpose of this study is to serve as a basis for selection of a final experiment geometry and heat load. The experiment consists of a pillar of undisturbed rock salt surrounded by an excavated annular room. The pillar surface is covered by a blanket heat source which is externally insulated. A total of five thermal and ten structural calculations are described in a four to five yearmore » experimental time frame. Results are presented which include relevant temperature-time histories, deformations, rock salt stress component and effective stress profiles, and maximum stresses in anhydrite layers which are in close proximity to the room. Also included are predicted contours of a conservative post-processed measure of potential salt failure. Observed displacement histories are seen to be highly dependent on pillar and room height, but insensitive to other geometrical variations. The use of a tensile cutoff across slidelines is seen to produce more accurate predictions of anhydrite maximum stress, but to have little effect on rock salt stresses. The potential for salt failure is seen to be small in each case for the time frame of interest, and is only seen at longer times in the center of the room floor.« less

Experience Modulates the Reproductive Response to Heat Stress in C. elegans via Multiple Physiological Processes

PubMed Central

Gouvêa, Devin Y.; Aprison, Erin Z.; Ruvinsky, Ilya

2015-01-01

Natural environments are considerably more variable than laboratory settings and often involve transient exposure to stressful conditions. To fully understand how organisms have evolved to respond to any given stress, prior experience must therefore be considered. We investigated the effects of individual and ancestral experience on C. elegans reproduction. We documented ways in which cultivation at 15°C or 25°C affects developmental time, lifetime fecundity, and reproductive performance after severe heat stress that exceeds the fertile range of the organism but is compatible with survival and future fecundity. We found that experience modulates multiple aspects of reproductive physiology, including the male and female germ lines and the interaction between them. These responses vary in their environmental sensitivity, suggesting the existence of complex mechanisms for coping with unpredictable and stressful environments. PMID:26713620

Effect of thermal interface on heat flow in carbon nanofiber composites.

PubMed

Gardea, F; Naraghi, M; Lagoudas, D

2014-01-22

The thermal transport process in carbon nanofiber (CNF)/epoxy composites is addressed through combined micromechanics and finite element modeling, guided by experiments. The heat exchange between CNF constituents and matrix is studied by explicitly accounting for interface thermal resistance between the CNFs and the epoxy matrix. The effects of nanofiber orientation and discontinuity on heat flow and thermal conductivity of nanocomposites are investigated through simulation of the laser flash experiment technique and Fourier's model of heat conduction. Our results indicate that when continuous CNFs are misoriented with respect to the average temperature gradient, the presence of interfacial resistance does not affect the thermal conductivity of the nanocomposites, as most of the heat flow will be through CNFs; however, interface thermal resistance can significantly alter the patterns of heat flow within the nanocomposite. It was found that very high interface resistance leads to heat entrapment at the interface near to the heat source, which can promote interface thermal degradation. The magnitude of heat entrapment, quantified via the peak transient temperature rise at the interface, in the case of high thermal resistance interfaces becomes an order of magnitude more intense as compared to the case of low thermal resistance interfaces. Moreover, high interface thermal resistance in the case of discontinuous fibers leads to a nearly complete thermal isolation of the fibers from the matrix, which will marginalize the contribution of the CNF thermal conductivity to the heat transfer in the composite.

Ion Bernstein wave heating research

NASA Astrophysics Data System (ADS)

Ono, Masayuki

1993-02-01

Ion Bernstein wave heating (IBWH) utilizes the ion Bernstein wave (IBW), a hot plasma wave, to carry the radio frequency (rf) power to heat the tokamak reactor core. Earlier wave accessibility studies have shown that this finite-Larmor-radius (FLR) mode should penetrate into a hot dense reactor plasma core without significant attenuation. Moreover, the IBW's low perpendicular phase velocity (ω/k⊥≊VTi≪Vα) greatly reduces the otherwise serious wave absorption by the 3.5 MeV fusion α particles. In addition, the property of IBW's that k⊥ρi≊1 makes localized bulk ion heating possible at the ion cyclotron harmonic layers. Such bulk ion heating can prove useful in optimizing fusion reactivity. In another vein, with proper selection of parameters, IBW's can be made subject to strong localized electron Landau damping near the major ion cyclotron harmonic resonance layers. This property can be useful, for example, for rf current drive in the reactor plasma core. IBW's can be excited with loop antennas or with a lower-hybrid-like waveguide launcher at the plasma edge, the latter structure being one that is especially compatible with reactor application. In either case, the mode at the plasma edge is an electron plasma wave (EPW). Deeper in the plasma, the EPW is mode transformed into an IBW. Such launching and mode transformation of IBW's were first demonstrated in experiments in the Advanced Concepts Torus-1 (ACT-1) [Phys. Rev. Lett. 45, 1105 (1980)] plasma torus and in particle simulation calculations. These and other aspects of IBW heating physics have been investigated through a number of experiments performed on ACT-1, the Japanese Institute of Plasma Physics Tokamak II-Upgrade (JIPPTII-U) [Phys. Rev. Lett. 54, 2339 (1985)], the Tokyo University Non-Circular Tokamak (TNT) [Nucl. Fusion 26, 1097 (1986)], the Princeton Large Tokamak (PLT) [Phys. Rev. Lett. 60, 294 (1988)], and Alcator-C [Phys. Rev. Lett. 60, 298 (1988)]. In these experiments both linear and nonlinear heating processes have been observed. Interestingly, improvement of plasma confinement was also observed in the PLT and Alcator-C experiments, opening up the possible use of IBW's for the active control of plasma transport. Two theoretical explanations have been proposed: one based on four-wave mixing of IBW with low-frequency turbulence, the other on the nonlinear generation of a velocity-shear layer. Both models are consistent with the observed threshold power level of a few hundred kW in the experiments. Experiments on lower field plasmas on JFTII-M [Eighth Topical Conference on Radio-Frequency Power in Plasmas, Irvine, CA, 1989 (American Institute of Physics, New York, 1989), p. 350] and DIII-D [Eighth Topical Conference on Radio-Frequency Power in Plasmas, Irvine, CA, 1989 (American Institute of Physics, New York, 1989), p. 314] have raised some concern with the IBW wave-launching process. The experiments showed serious impurity release from the walls but little or no core heating, a combination of circumstances strongly suggestive of edge heating. Possible parasitic channels could include the excitation of short wavelength modes by the Faraday shield's fringing fields, antenna-sheath-wave excitation, an axial-convective loss channel, and nonlinear processes such as parametric instability and ponderomotive effects. Suggested remedies include changes in the antenna phasing, the use of low-Z insulators, operating at higher frequencies, positioning the plasma differently with respect to the antenna, eliminating the Faraday shields, and using a waveguide launcher. The recent JIPPTII-U experiment, employing a 0-π phased antenna array with a higher frequency 130 MHz source, demonstrated that those remedies can indeed work. Looking to the future, one seeks additional ways in which IBWH can improve tokamak performance. The strong ponderomotive potential of the IBWH antenna may be used to stabilize external kinks and, acting as an rf limiter, to control the plasma edge. Control of the plasma pressure profile with local IBWH heating is already an important part of the Princeton Beta Experiment-Modified (PBX-M) [Ninth Topical Conference on Radio-Frequency Power in Plasmas, Charleston, SC, 1991 (American Institute of Physics, New York, 1991), p. 129] program in its exploration of the second-stability regime. Application of IBWH may also improve the performance of neutral beam heating and the efficiency and localization of lower-hybrid current drive for current profile control. Used with pellet injection, IBWH may also prolong the period of good confinement. The three planned high-power IBWH experiments covering vastly different parameters: f=40-80 MHz for PBX-M; f=130 MHz for JIPPT-II-U; and f=430 MHz for the Frascati Tokamak-Upgrade (FT-U) [16th European Physical Society Conference on Controlled Fusion and Plasma Physics, Venice, Italy, 1989 (European Physical Society, Amsterdam, 1989), Vol. III, p. 1069] appear to be well positioned to explore these possibilities and to clarify other issues including the physics of wave launching and associated nonlinear processes.

Engineering aspects of the HT-6M Tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-05-01

The HT-6M is a medium-sized tokamak being built in China. The principal aim of the project is to study high-power auxiliary heating (1-MW neutral beam injection, 1-MW ion cyclotron resonance heating, and 100-kW electron cyclotron resonance heating), high-..beta.. experiments, the transport process, and the formation and diffusion process of impurities. The main device parameters are: major plasma radius R = 65 cm, minor plasma radius a = 20 cm, plasma current I/subP/ = 150 kA, discharge time tau = 150 ms, toroidal field B/subT/ = 15 kG. Simplicity of construction, accessibility to the plasma, reliability in operation, and convenience formore » maintenance were particularly emphasized in the design. The important design features of the device and power supply system are described.« less

Microgravity

NASA Image and Video Library

1995-09-15

Large Isothermal Furnace (LIF) was flown on a mission in cooperation with the National Space Development Agency (NASDA) of Japan. LIF is a vacuum-heating furnace designed to heat large samples uniformly. The furnace consists of a sample container and heating element surrounded by a vacuum chamber. A crewmemeber will insert a sample cartridge into the furnace. The furnace will be activated and operations will be controlled automatically by a computer in response to an experiment number entered on the control panel. At the end of operations, helium will be discharged into the furnace, allowing cooling to start. Cooling will occur through the use of a water jacket while rapid cooling of samples can be accomplished through a controlled flow of helium. Data from experiments will help scientists better understand this important process which is vital to the production of high-quality semiconductor crystals.

Mixed convection heat transfer: an experimental study on Cu/heat transfer oil nanofluids inside annular tube

NASA Astrophysics Data System (ADS)

Abbasian Arani, Ali Akbar; Aberoumand, Hossein; Jafarimoghaddam, Amin; Aberoumand, Sadegh

2017-09-01

The heat transfer and flow characteristics of Cu-heat transfer oil nanofluid during mixed convection through horizontal annular tubes under uniform heat flux as boundary condition are investigated experimentally. Data were acquired at low Reynolds number ranged from about 26 to 252. The applied nanofluid prepared by Electrical Explosion of Wire technique with no nanoparticles agglomeration during nanofluid preparation process and experiments. Pure heat transfer oil and nanofluids with nanoparticles weight concentrations of 0.12, 0.36 and 0.72% were used as the working fluids. Based on these results, Effects of nanoparticles concentration, heat flux and free convection on the thermal field development are studied under buoyancy assisted flow condition for Grashof number, Richardson number between 2820 and 12,686, and 0.1-10, respectively. Results show that Nusselt number increases with an increase of nanoparticles weight concentrations from 0 to 0.72% under certain Richardson numbers.

Alpha heating and isotopic mass effects in JET plasmas with sawteeth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budny, R. V.; Team, JET

2016-02-09

The alpha heating experiment in the Joint European Torus (JET) 1997 DTE1 campaign is re-examined. Several effects correlated with tritium content and thermal hydrogenic isotopic mass < A> weaken the conclusion that alpha heating was clearly observed. These effects delayed the occurrence of significant sawtooth crashes allowing the electron and ion temperatures T e and T i to achieve higher values. Under otherwise equal circumstances T e and T i were typically higher for discharges with higher < A >, and significant scaling of T i, T e, and total stored energy with < A > were observed. The highermore » T i led to increased ion–electron heating rates with magnitudes comparable to those computed for alpha electron heating. Rates of other heating/loss processes also had comparable magnitudes. Simulations of T e assuming the observed scaling of T i are qualitatively consistent with the measured profiles, without invoking alpha heating« less

Correlating measured transient temperature rises with damage rate processes in cultured cells

NASA Astrophysics Data System (ADS)

Denton, Michael L.; Tijerina, Amanda J.; Gonzalez, Cherry C.; Gamboa, B. Giovana; Noojin, Gary D.; Ahmed, Elharith M.; Rickman, John M.; Dyer, Phillip H.; Rockwell, Benjamin A.

2017-02-01

Thermal damage rate processes in biological tissues are usually characterized by a kinetics approach. This stems from experimental data that show how the transformation of a specified biological property of cells or biomolecule (plating efficiency for viability, change in birefringence, tensile strength, etc.) is dependent upon both time and temperature. Here, two disparate approaches were used to study thermal damage rate processes in cultured retinal pigment epithelial cells. Laser exposure (photothermal) parameters included 2-μm laser exposure of non-pigmented cells and 532-nm exposures of cells possessing a variety of melanosome particle densities. Photothermal experiments used a mid-IR camera to record temperature histories with spatial resolution of about 8 μm, while fluorescence microscopy of the cell monolayers identified threshold damage at the boundary between live and dead cells. Photothermal exposure durations ranged from 0.05-20 s, and the effects of varying ambient temperature were investigated. Temperature during heat transfer using a water-jacketed cuvette was recorded with a fast microthermister, while damage and viability of the suspended cells were determined as percentages. Exposure durations for the heat transfer experiments ranged from 50- 60 s. Empirically-determined kinetic parameters for the two heating methods were compared with each other, and with values found in the literature.

A Didactic Experiment and Model of a Flat-Plate Solar Collector

ERIC Educational Resources Information Center

Gallitto, Aurelio Agliolo; Fiordilino, Emilio

2011-01-01

We report on an experiment performed with a home-made flat-plate solar collector, carried out together with high-school students. To explain the experimental results, we propose a model that describes the heating process of the solar collector. The model accounts quantitatively for the experimental data. We suggest that solar-energy topics should…

Welding Metallurgy and Processing Issues for Joining of Power Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lienert, Thomas J.; Reardon, Patrick T.

2012-08-14

Weldability issues with the pertinent alloys have been reviewed and preliminary results of our work on Haynes 25 have been presented. Further results on the mechanical properties and metallography on the EB welds are imminent. Hot-ductility experiments will commence within a few weeks. Aging studies on the effects of heat treatment using the Gleeble are also planned. MST-6 has extensive background in the welding metallurgy of the pertinent alloys. We also have considerable experience with the various welding processes to be used.

Containerless solidification of BiFeO3 oxide under microgravity

NASA Astrophysics Data System (ADS)

Yu, Jianding; Arai, Yasutomo; Koshikawa, Naokiyo; Ishikawa, Takehito; Yoda, Shinichi

1999-07-01

Containerless solidification of BiFeO3 oxide has been carried out under microgravity with Electrostatic Levitation Furnace (ELF) aboard on the sounding rocket (TR-IA). It is a first containerless experiment using ELF under microgravity for studying the solidification of oxide insulator material. Spherical BiFeO3 sample with diameter of 5mm was heated by two lasers in oxygen and nitrogen mixing atmosphere, and the sample position by electrostatic force under pinpoint model and free drift model. In order to compare the solidification behavior in microgravity with on ground, solidification experiments of BiFeO3 in crucible and drop tube were carried out. In crucible experiment, it was very difficult to get single BiFeO3 phase, because segregation of Fe2O3 occured very fast and easily. In drop tube experiment, fine homogeneous BiFeO3 microstructure was obtained in a droplet about 300 μm. It implies that containerless processing can promote the phase selection in solidification. In microgravity experiment, because the heating temperature was lower than that of estimated, the sample was heated into Fe2O3+liquid phase region. Fe2O3 single crystal grew on the surface of the spherical sample, whose sample was clearly different from that observed in ground experiments.

Heat stress enhances LTM formation in Lymnaea: role of HSPs and DNA methylation.

PubMed

Sunada, Hiroshi; Riaz, Hamza; de Freitas, Emily; Lukowiak, Kai; Swinton, Cayley; Swinton, Erin; Protheroe, Amy; Shymansky, Tamila; Komatsuzaki, Yoshimasa; Lukowiak, Ken

2016-05-01

Environmentally relevant stressors alter the memory-forming process in Lymnaea following operant conditioning of aerial respiration. One such stressor is heat. Previously, we found that following a 1 h heat shock, long-term memory (LTM) formation was enhanced. We also had shown that the heat stressor activates at least two heat shock proteins (HSPs): HSP40 and HSP70. Here, we tested two hypotheses: (1) the production of HSPs is necessary for enhanced LTM formation; and (2) blocking DNA methylation prevents the heat stressor-induced enhancement of LTM formation. We show here that the enhancing effect of the heat stressor on LTM formation occurs even if snails experienced the stressor 3 days previously. We further show that a flavonoid, quercetin, which inhibits HSP activation, blocks the enhancing effect of the heat stressor on LTM formation. Finally, we show that injection of a DNA methylation blocker, 5-AZA, before snails experience the heat stressor prevents enhancement of memory formation. © 2016. Published by The Company of Biologists Ltd.

Influence of dimension parameters of the gravity heat pipe on the thermal performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kosa, Ľuboš, E-mail: lubos.kosa@fstroj.uniza.sk; Nemec, Patrik, E-mail: patrik.nemec@fstroj.uniza.sk; Jobb, Marián, E-mail: marian.jobb@fstroj.uniza.sk

Currently the problem with the increasing number of electronic devices is a problem with the outlet Joule heating. Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. Perfect dustproof cooling of electronic components ensures longer life of the equipment. One of more alternatives of heat transfer without the using of mechanical equipment is the use of the heat pipe. Heat pipes are easy to manufacture and maintenance of low input investment cost. The advantage of using the heat pipe is its use inmore » hermetic closed electronic device which is separated exchange of air between the device and the environment. This experiment deals with the influence of changes in the working tube diameter and changing the working fluid on performance parameters. Changing the working fluid and the tube diameter changes the thermal performance of the heat pipe. The result of this paper is finding the optimal diameter with ideal working substance for the greatest heat transfer for 1cm{sup 2} sectional area tube.« less

Thermo-mechanical simulation of liquid-supported stretch blow molding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zimmer, J.; Stommel, M.

2015-05-22

Stretch blow molding is the well-established plastics forming method to produce Polyehtylene therephtalate (PET) bottles. An injection molded preform is heated up above the PET glass transition temperature (Tg∼85°C) and subsequently inflated by pressurized air into a closed cavity. In the follow-up filling process, the resulting bottle is filled with the final product. A recently developed modification of the process combines the blowing and filling stages by directly using the final liquid product to inflate the preform. In a previously published paper, a mechanical simulation and successful evaluation of this liquid-driven stretch blow molding process was presented. In this way,more » a realistic process parameter dependent simulation of the preform deformation throughout the forming process was enabled, whereas the preform temperature evolution during forming was neglected. However, the formability of the preform is highly reduced when the temperature sinks below Tg during forming. Experimental investigations show temperature-induced failure cases due to the fast heat transfer between hot preform and cold liquid. Therefore, in this paper, a process dependent simulation of the temperature evolution during processing to avoid preform failure is presented. For this purpose, the previously developed mechanical model is used to extract the time dependent thickness evolution. This information serves as input for the heat transfer simulation. The required material parameters are calibrated from preform cooling experiments recorded with an infrared-camera. Furthermore, the high deformation ratios during processing lead to strain induced crystallization. This exothermal reaction is included into the simulation by extracting data from preform measurements at different stages of deformation via Differential Scanning Calorimetry (DSC). Finally, the thermal simulation model is evaluated by free forming experiments, recorded by a high-speed infrared camera.« less

RUBI -a Reference mUltiscale Boiling Investigation for the Fluid Science Laboratory

NASA Astrophysics Data System (ADS)

Schweizer, Nils; Stelzer, Marco; Schoele-Schulz, Olaf; Picker, Gerold; Ranebo, Hans; Dettmann, Jan; Minster, Olivier; Toth, Balazs; Winter, Josef; Tadrist, Lounes; Stephan, Peter; Grassi, Walter; di Marco, Paolo; Colin, Catherine; Piero Celata, Gian; Thome, John; Kabov, Oleg

Boiling is a two-phase heat transfer process where large heat fluxes can be transferred with small driving temperature differences. The high performance of boiling makes the process very interesting for heat transfer applications and it is widely used in industry for example in power plants, refrigeration systems, and electronics cooling. Nevertheless, due to the large number of involved phenomena and their often highly dynamic nature a fundamental understanding and closed theoretical description is not yet accomplished. The design of systems incorporating the process is generally based on empirical correlations, which are commonly accompanied by large uncertainties and, thus, has to be verified by expensive test campaigns. Hence, strong efforts are currently made to develop applicable numerical tools for a reliable prediction of the boiling heat transfer performance and limits. In order to support and validate this development and, in particular as a precondition, to enhance the basic knowledge about boiling the comprehensive multi-scale experiment RUBI (Reference mUlti-scale Boiling Investigation) for the Fluid Science Laboratory on board the ISS is currently in preparation. The scientific objectives and requirements of RUBI have been defined by the members of the ESA topical team "Boiling and Multiphase Flow" and addresses fundamental aspects of boiling phenomena. The main objectives are the measurement of wall temperature and heat flux distribution underneath vapour bubbles with high spatial and tem-poral resolution by means of IR thermography accompanied by the synchronized high-speed observation of the bubble shapes. Furthermore, the fluid temperature in the vicinity and inside of the bubbles will be measured by a micro sensor array. Additional stimuli are the generation of an electric field above the heating surface and a shear flow created by a forced convection loop. The objective of these stimuli is to impose forces on the bubbles and investigate the resulting bubble behaviour such as bubble sliding on and detaching from the surface. The experiments benefits from the absence of vapour buoyancy and natural convection in the high quality and long-term microgravity of the ISS. Effects and phenomena like thermocapillary convection that are hardly observable in normal gravity conditions can be investigated. Clearly predefined conditions particularly of the thermal layer at the heating surface can be established without disturbances by natural convection. Vapour buoyancy as the main detaching force in normal gravity is missing. Hence, it is possible to study stationary, attached bubbles and alternative detaching forces. With RUBI a long history of boiling experiments is perpetuated that used microgravity as a tool for a deeper understanding of the fundamental phenomena. Several precursor experiments closely related to the RUBI project have already been conducted on parabolic flights. The subject of the paper is to provide an overview on the RUBI project, its scientific objectives and the corresponding experimental principle. The current design of the experiment container that is under development at ASTRIUM Space Transportation in Friedrichshafen will be introduced. Furthermore, results from the precursor experiments are presented. The industrial activities of the RUBI project are funded and the science team is supported by ESA.

Transition from Pool to Flow Boiling: The Effect of Reduced Gravity

NASA Technical Reports Server (NTRS)

Dhir, Vijay K.

2004-01-01

Applications of boiling heat transfer in space can be found in the areas of thermal management, fluid handling and control, power systems, on-orbit storage and supply systems for cryogenic propellants and life support fluids, and for cooling of electronic packages for power systems associated with various instrumentation and control systems. Recent interest in exploration of Mars and other planets, and the concepts of in-situ resource utiliLation on Mars highlights the need to understand the effect of gravity on boiling heat transfer at gravity levels varying from 1>= g/g(sub e) >=10(exp -6). The objective of the proposed work was to develop a mechanistic understanding of nucleate boiling and critical heat flux under low and micro-gravity conditions when the velocity of the imposed flow is small. For pool boiling, the effect of reduced gravity is to stretch both the length scale as well as the time scale for the boiling process. At high flow velocities, the inertia of the liquid determines the time and the length scales and as such the gravitational acceleration plays little role. However, at low velocities and at low gravity levels both liquid inertia and buoyancy are of equal importance. At present, we have little understanding of the interacting roles of gravity and liquid inertia on the nucleate boiling process. Little data that has been reported in the literature does not have much practical value in that it can not serve as a basis for design of heat exchange components to be used in space. Both experimental and complete numerical simulations of the low velocity, low-gravity nucleate boiling process were carried out. A building block type of approach was used in that first the growth and detachment process of a single bubble and flow and heat transfer associated with the sliding motion of the bubble over the heater surface after detachment was studied. Liquid subcooling and flow velocity were varied parametrically. The experiments were conducted at 1 g(sub e), while varying the orientation of surface with respect to the gravity vector. In the laboratory experiments, holographic interferometry was used to obtain data on velocity and temperature fields associated with a bubble prior to, and after detachment and during sliding motion. A test rig for conducting experiments in the KC-135 was developed, but experiments could not be conducted due to the unavailability of the aircraft prior to completion of the project. Numerical simulations modeling the micro and macro regions of the bubble were carried out in three dimensions. The results of the experiments were used to validate analytical/numerical models.

Toward Assessing the Causes of Volcanic Diversity in the Cascades Arc

NASA Astrophysics Data System (ADS)

Till, C. B.; Kent, A. J.; Abers, G. A.; Pitcher, B.; Janiszewski, H. A.; Schmandt, B.

2017-12-01

A fundamental unanswered question in subduction system science is the cause of the observed diversity in volcanic arc style at an arc-segment to whole-arc scale. Specifically, we have yet to distinguish the predominant mantle and crustal processes responsible for the diversity of arc volcanic phenomenon, including the presence of central volcanoes vs. dispersed volcanism; episodicity in volcanic fluxes in time and space; variations in magma chemistry; and differences in the extent of magmatic focusing. Here we present a thought experiment using currently available data to estimate the relative role of crustal magmatic processes in producing the observed variations in Cascades arc volcanism. A compilation of available major element compositions of Quaternary arc volcanism and estimates of eruptive volumes are used to examine variations in the composition of arc magmas along strike. We then calculate the Quaternary volcanic heat flux into the crust, assuming steady state, required to produce the observed distribution of compositions via crystallization of mantle-derived primitive magmas vs. crustal melting using experiment constraints on possible liquid lines of descent and crustal melting scenarios. For pure crystallization, heat input into the crust scales with silica content, with dacitic to rhyolite compositions producing significantly greater latent heat relative to basalts to andesites. In contrast, the heat required to melt lower crustal amphibolite decreases with increasing silica and is likely provided by the latent heat of crystallization. Thus we develop maximum and minimum estimates for heat added to the crust at a given SiO2 range. When volumes are considered, we find that the average Quaternary volcanic heat flux at latitudes south of South Sister to be more than twice that to the north. Distributed mafic volcanism produces only a quarter to half the heat flux calculated for the main edifices at a given latitude because of their lesser eruptive volumes and quantities of evolved magma. When we compare our Quaternary heat flux calculations to a variety of geophysical observations, we find that regions of calculated higher volcanic heat flux coincide with regions of significantly lower crustal seismic wave speeds beneath and behind the arc, as well as with regions of significantly higher heat flow.

High Temperature, Slow Strain Rate Forging of Advanced Disk Alloy ME3

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.; OConnor, Kenneth

2001-01-01

The advanced disk alloy ME3 was designed in the HSR/EPM disk program to have extended durability at 1150 to 1250 F in large disks. This was achieved by designing a disk alloy and process producing balanced monotonic, cyclic, and time-dependent mechanical properties. combined with robust processing and manufacturing characteristics. The resulting baseline alloy, processing, and supersolvus heat treatment produces a uniform, relatively fine mean grain size of about ASTM 7, with as-large-as (ALA) grain size of about ASTM 3. There is a long term need for disks with higher rim temperature capabilities than 1250 F. This would allow higher compressor exit (T3) temperatures and allow the full utilization of advanced combustor and airfoil concepts under development. Several approaches are being studied that modify the processing and chemistry of ME3, to possibly improve high temperature properties. Promising approaches would be applied to subscale material, for screening the resulting mechanical properties at these high temperatures. n obvious path traditionally employed to improve the high temperature and time-dependent capabilities of disk alloys is to coarsen the grain size. A coarser grain size than ASTM 7 could potentially be achieved by varying the forging conditions and supersolvus heat treatment. The objective of this study was to perform forging and heat treatment experiments ("thermomechanical processing experiments") on small compression test specimens of the baseline ME3 composition, to identify a viable forging process allowing significantly coarser grain size targeted at ASTM 3-5, than that of the baseline, ASTM 7.

Air-cooling characteristics of simulated grape packages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederick, R.L.; Comunian, F.

Experimental simulation of the external forced convection on the outside of grape packages was performed. Average heat transfer coefficients for air flow around such containers were found to range from 8 to 13.4 W/(m[sup 2]K). A physical description of the convective process was formulated on the basis of data obtained in three types of experiment. Expressions for the average heat transfer coefficient from single packages in air flow were proposed.

Nanoparticle coating of a microchannel surface is an effective method for increasing the critical heat flux

NASA Astrophysics Data System (ADS)

Shustov, M. V.; Kuzma-Kichta, Yu. A.; Lavrikov, A. V.

2017-04-01

Results are presented of an investigation into water boiling in a single microchannel 0.2 mm high, 3 mm wide, and 13.7 mm long with a smooth heating surface or with a coating from aluminum oxide nanoparticles. The experimental procedure and the test setup are described. The top wall of the microchannel is made of glass so that video recording in the reflected light of the process can be made. A coating of Al2O3 particles is applied onto the heating surface before the experiments using a method developed by the authors of the paper. The experiments yielded data on heat transfer and void fraction and its fluctuations for the bubble and transient boiling in the microchannel. The dependence was established of the heat flux on the temperature of the microchannel wall with a smooth surface or a surface with Al2O3 nanoparticle coating for various mass flows in the microchannel. The boiling crisis has been found to occur in the microchannel with a nanoparticle coating at a considerably higher heat flux than that in the channel without coating. The experimental data also suggest that the nanoparticle coating improves heat transfer in the transition boiling region. Processing of the data obtained using a high-speed video revealed void fraction fluctuations enabling us to describe two-phase flow regimes with the flow boiling in a microchannel. It has been found that a return flow occurs in the microchannel under certain conditions. A hypothesis for its causes is proposed. The dependence of the void fraction on the steam quality in the microchannel with or without a nanoparticle coating was determined from the video records. The experimental data on void fraction for boiling in the microchannel without coating are approximated by an empirical correlation. The experiments demonstrate that the void fraction during boiling in the microchannel with a nanoparticle coating is higher than during boiling in the channel without coating (where φ and x are the void fraction and the steam quality, respectively) in the region of a sharp increase in the φ( x) curve.

Vertical structure and physical processes of the Madden-Julian Oscillation: Biases and uncertainties at short range

DOE PAGES

Xavier, Prince K.; Petch, Jon C.; Klingaman, Nicholas P.; ...

2015-05-26

We present an analysis of diabatic heating and moistening processes from 12 to 36 h lead time forecasts from 12 Global Circulation Models as part of the “Vertical structure and physical processes of the Madden-Julian Oscillation (MJO)” project. A lead time of 12–36 h is chosen to constrain the large-scale dynamics and thermodynamics to be close to observations while avoiding being too close to the initial spin-up of the models as they adjust to being driven from the Years of Tropical Convection (YOTC) analysis. A comparison of the vertical velocity and rainfall with the observations and YOTC analysis suggests thatmore » the phases of convection associated with the MJO are constrained in most models at this lead time although the rainfall in the suppressed phase is typically overestimated. Although the large-scale dynamics is reasonably constrained, moistening and heating profiles have large intermodel spread. In particular, there are large spreads in convective heating and moistening at midlevels during the transition to active convection. Radiative heating and cloud parameters have the largest relative spread across models at upper levels during the active phase. A detailed analysis of time step behavior shows that some models show strong intermittency in rainfall and differences in the precipitation and dynamics relationship between models. In conclusion, the wealth of model outputs archived during this project is a very valuable resource for model developers beyond the study of the MJO. Additionally, the findings of this study can inform the design of process model experiments, and inform the priorities for field experiments and future observing systems.« less

Stovetop Earth Pecan Pie

NASA Astrophysics Data System (ADS)

Robin, C. M.

2005-12-01

Many fluid mechanical experiments with direct applications to Earth Science are performed with sugary syrups using conceptually straightforward procedures. Corn syrup has indeed proven to be a godsend for those studying convection and related non-linear phenomena. In addition, however, it gives experimentalists a deep physical intuition for the interior workings of hot planets. The basic concepts behind plate tectonics and mantle convection are not difficult; indeed, although they may not be aware of it, most students probably have a basic intuitive understanding of fluid mechanics gained in their daily life. However, the large size and long time scale of geophysical processes may be quite intimidating to young students. Even a simple geophysical experiment requires a complicated array of coolers, heaters and measuring and recording equipment. It is of interest to introduce students to the geodynamical concepts that can be visualized in a high-tech lab using familiar processes and equipment. Using a homemade apparatus and grocery store supplies, I propose using a 'Stove-top Earth pecan pie' to introduce simple geodynamic concepts to middle- and high-school students. The initially cold syrup heats up and the pecans begin to float (continent formation), the syrup begins to convect (mantle convection), and convection slows down after the heat is removed (secular cooling). Even Wilson cycles can be simulated by moving the pan to one side or the other of the stovetop or heating element. The activity formally introduces students to convection and its application to the earth, and makes them think about plate motion, heat transfer, scaling, and experimental procedures. As an added bonus, they can eat their experiments after recess!

The Viking biological investigation - Preliminary results

NASA Technical Reports Server (NTRS)

Klein, H. P.; Oyama, V. I.; Berdahl, B. J.; Horowitz, N. H.; Hobby, G. L.; Levin, G. V.; Straat, P. A.; Lederberg, J.; Rich, A.; Hubbard, J. S.

1976-01-01

A preliminary progress report is presented for the Viking biological investigation through its first month. The carbon assimilation, gas exchange, and labeled release experiments are described in detail, and the chronology of the experiments is outlined. For the first experiment, it is found that a small amount of gas was converted into organic material in one sample and that heat treatment of a duplicate sample prevented such conversion. In the second experiment, a substantial amount of O2 was detected along with significant increases in CO2 and small changes in N2. In the third experiment, a significant amount of radioactive gas was evolved from one sample, but not from a duplicate heat-treated sample. Possible biological and nonbiological interpretations are considered for these results. It is concluded that while the experiments provide clear evidence for the occurrence of chemical reactions and while the results do not violate any prima facie criteria for biological processes, a definitive answer cannot yet be given to the question of whether life exists on Mars.

Impact of various operating modes on performance and emission parameters of small heat source

NASA Astrophysics Data System (ADS)

Vician, Peter; Holubčík, Michal; Palacka, Matej; Jandačka, Jozef

2016-06-01

Thesis deals with the measurement of performance and emission parameters of small heat source for combustion of biomass in each of its operating modes. As the heat source was used pellet boiler with an output of 18 kW. The work includes design of experimental device for measuring the impact of changes in air supply and method for controlling the power and emission parameters of heat sources for combustion of woody biomass. The work describes the main factors that affect the combustion process and analyze the measurements of emissions at the heat source. The results of experiment demonstrate the values of performance and emissions parameters for the different operating modes of the boiler, which serve as a decisive factor in choosing the appropriate mode.

Heat transfer enhancement at increasing water concentration in alcohol in the process of non-stationary film boiling

NASA Astrophysics Data System (ADS)

Kanin, P. K.; Ryazantsev, V. A.; Lexin, M. A.; Zabirov, A. R.; Yagov, V. V.

2018-03-01

New experimental data on heat transfer in pool film boiling of subcooled ethanol-water mixtures at spherical surfaces are considered. The water solutions with ethanol mass fraction from 10 to 91% and temperature of liquid 50°C were examined. All the experiments were conducted under atmospheric pressure, using the stainless steel sphere of 39 mm in diameter as a cooled body. The sphere was heated up to 450-750°C, depending on ethanol concentration, and immersed into the experimental vessel with subcooled mixture. As it is expected, boiling heat transfer intensifies with ethanol concentration decrease, and duration of cooling decreases. It means that stable film boiling duration decreases, and earlier transition to intensive heat transfer regime occurs.

Experiment plans to study preignition processes of a pool fire in low gravity. M.S. Thesis - 1988 Final Report

NASA Technical Reports Server (NTRS)

Schiller, David N.

1989-01-01

Science requirements are specified to guide experimental studies of transient heat transfer and fluid flow in an enclosure containing a two-layer gas-and-liquid system heated unevenly from above. Specifications are provided for experiments in three separate settings: (1) a normal gravity laboratory, (2) the NASA-LeRC Drop towers, and (3) a space-based laboratory (e.g., Shuttle, Space Station). A rationale is developed for both minimum and desired requirement levels. The principal objective of the experimental effort is to validate a computational model of the enclosed liquid fuel pool during the preignition phase and to determine via measurement the role of gravity on the behavior of the system. Preliminary results of single-phase normal gravity experiments and simulations are also presented.

Experimental constraints on the origin of chondrules

NASA Astrophysics Data System (ADS)

Boynton, W. V.; Drake; Hildebrand; Jones; Lewis; Treiman; Wark

1987-11-01

Chrondule formation was an important (perhaps ubiguitous) process in the early solar system, yet their origins remain elusive. Some points, however, are clear. The precursor material of chondules (dust) was rapidly heated at rates of perhaps thousands of degrees per second and was cooled more slowly. It was proposed to investigate chondrule formation in the Space Station environment via a dust-box (a chamber in which dust can be suspended, heated, and cooled. A microgravity environment is conducive to this kind of experiment because of the significant retardation of settling rates compared with a terrestrial laboratory environment. These long-duration experiments might require the development of technologies to counteract even the small, but finite and permanent gravitation field of the Space Station. Simple, but interesting experiments on dust suspensions immediately present themselves.

Exothermic furnace module development. [space processing

NASA Technical Reports Server (NTRS)

Darnell, R. R.; Poorman, R. M.

1982-01-01

An exothermic furnace module was developed to rapidly heat and cool a 0.820-in. (2.1 cm) diameter by 2.75-in. (7.0 cm) long TZM molybdenum alloy crucible. The crucible contains copper, oxygen, and carbon for processing in a low-g environment. Peak temperatures of 1270 C were obtainable 3.5 min after start of ignition, and cooling below 950 C some 4.5 min later. These time-temperature relationships were conditioned for a foam-copper experiment, Space Processing Applications Rocket experiment 77-9, in a sounding rocket having a low-g period of 5 min.

DIY soundcard based temperature logging system. Part II: applications

NASA Astrophysics Data System (ADS)

Nunn, John

2016-11-01

This paper demonstrates some simple applications of how temperature logging systems may be used to monitor simple heat experiments, and how the data obtained can be analysed to get some additional insight into the physical processes.

Analysis of Microgravity Experiments Conducted on the Apollo Spacecraft

NASA Technical Reports Server (NTRS)

Sharpe, R. J.; Wright, M. D.

2009-01-01

This Technical Memorandum (TM) discusses the microgravity experiments carried out during the later missions of the Apollo program. Microgravity experiments took place during the Apollo 14, 16, and 17 missions and consisted of four experiments in various materials processing concentrations with two of the four experiments taking place over the course of two missions. Experiments consist of composite casting, electrophoresis, heat flow and convection, and liquid transfer. This TM discusses the background, the workup, execution, and results of each experiment. In addition, the historical significance of each experiment to future applications/NASA programs is discussed.

The bromodomain protein BRD4 regulates splicing during heat shock.

PubMed

Hussong, Michelle; Kaehler, Christian; Kerick, Martin; Grimm, Christina; Franz, Alexandra; Timmermann, Bernd; Welzel, Franziska; Isensee, Jörg; Hucho, Tim; Krobitsch, Sylvia; Schweiger, Michal R

2017-01-09

The cellular response to heat stress is an ancient and evolutionarily highly conserved defence mechanism characterised by the transcriptional up-regulation of cyto-protective genes and a partial inhibition of splicing. These features closely resemble the proteotoxic stress response during tumor development. The bromodomain protein BRD4 has been identified as an integral member of the oxidative stress as well as of the inflammatory response, mainly due to its role in the transcriptional regulation process. In addition, there are also several lines of evidence implicating BRD4 in the splicing process. Using RNA-sequencing we found a significant increase in splicing inhibition, in particular intron retentions (IR), following heat treatment in BRD4-depleted cells. This leads to a decrease of mRNA abundancy of the affected transcripts, most likely due to premature termination codons. Subsequent experiments revealed that BRD4 interacts with the heat shock factor 1 (HSF1) such that under heat stress BRD4 is recruited to nuclear stress bodies and non-coding SatIII RNA transcripts are up-regulated. These findings implicate BRD4 as an important regulator of splicing during heat stress. Our data which links BRD4 to the stress induced splicing process may provide novel mechanisms of BRD4 inhibitors in regard to anti-cancer therapies. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Laboratory experimental investigation of heat transport in fractured media

NASA Astrophysics Data System (ADS)

Cherubini, Claudia; Pastore, Nicola; Giasi, Concetta I.; Allegretti, Nicoletta Maria

2017-01-01

Low enthalpy geothermal energy is a renewable resource that is still underexploited nowadays in relation to its potential for development in society worldwide. Most of its applications have already been investigated, such as heating and cooling of private and public buildings, road defrosting, cooling of industrial processes, food drying systems or desalination. Geothermal power development is a long, risky and expensive process. It basically consists of successive development stages aimed at locating the resources (exploration), confirming the power generating capacity of the reservoir (confirmation) and building the power plant and associated structures (site development). Different factors intervene in influencing the length, difficulty and materials required for these phases, thereby affecting their cost. One of the major limitations related to the installation of low enthalpy geothermal power plants regards the initial development steps that are risky and the upfront capital costs that are huge. Most of the total cost of geothermal power is related to the reimbursement of invested capital and associated returns. In order to increase the optimal efficiency of installations which use groundwater as a geothermal resource, flow and heat transport dynamics in aquifers need to be well characterized. Especially in fractured rock aquifers these processes represent critical elements that are not well known. Therefore there is a tendency to oversize geothermal plants. In the literature there are very few studies on heat transport, especially on fractured media. This study is aimed at deepening the understanding of this topic through heat transport experiments in fractured networks and their interpretation. Heat transfer tests have been carried out on the experimental apparatus previously employed to perform flow and tracer transport experiments, which has been modified in order to analyze heat transport dynamics in a network of fractures. In order to model the obtained thermal breakthrough curves, the Explicit Network Model (ENM) has been used, which is based on an adaptation of Tang's solution for the transport of the solutes in a semi-infinite single fracture embedded in a porous matrix. Parameter estimation, time moment analysis, tailing character and other dimensionless parameters have permitted a better understanding of the dynamics of heat transport and the efficiency of heat exchange between the fractures and the matrix. The results have been compared with the previous experimental studies on solute transport.

Validation of design procedure and performance modeling of a heat and fluid transport field experiment in the unsaturated zone

NASA Astrophysics Data System (ADS)

Nir, A.; Doughty, C.; Tsang, C. F.

Validation methods which developed in the context of deterministic concepts of past generations often cannot be directly applied to environmental problems, which may be characterized by limited reproducibility of results and highly complex models. Instead, validation is interpreted here as a series of activities, including both theoretical and experimental tests, designed to enhance our confidence in the capability of a proposed model to describe some aspect of reality. We examine the validation process applied to a project concerned with heat and fluid transport in porous media, in which mathematical modeling, simulation, and results of field experiments are evaluated in order to determine the feasibility of a system for seasonal thermal energy storage in shallow unsaturated soils. Technical details of the field experiments are not included, but appear in previous publications. Validation activities are divided into three stages. The first stage, carried out prior to the field experiments, is concerned with modeling the relevant physical processes, optimization of the heat-exchanger configuration and the shape of the storage volume, and multi-year simulation. Subjects requiring further theoretical and experimental study are identified at this stage. The second stage encompasses the planning and evaluation of the initial field experiment. Simulations are made to determine the experimental time scale and optimal sensor locations. Soil thermal parameters and temperature boundary conditions are estimated using an inverse method. Then results of the experiment are compared with model predictions using different parameter values and modeling approximations. In the third stage, results of an experiment performed under different boundary conditions are compared to predictions made by the models developed in the second stage. Various aspects of this theoretical and experimental field study are described as examples of the verification and validation procedure. There is no attempt to validate a specific model, but several models of increasing complexity are compared with experimental results. The outcome is interpreted as a demonstration of the paradigm proposed by van der Heijde, 26 that different constituencies have different objectives for the validation process and therefore their acceptance criteria differ also.

Recycling of spent adsorbents for oxyanions and heavy metal ions in the production of ceramics.

PubMed

Verbinnen, Bram; Block, Chantal; Van Caneghem, Jo; Vandecasteele, Carlo

2015-11-01

Spent adsorbents for oxyanion forming elements and heavy metals are classified as hazardous materials and they are typically treated by stabilization/solidification before landfilling. The use of lime or cement for stabilization/solidification entails a high environmental impact and landfilling costs are high. This paper shows that mixing spent adsorbents in the raw material for the production of ceramic materials is a valuable alternative to stabilize oxyanion forming elements and heavy metals. The produced ceramics can be used as construction material, avoiding the high economic and environmental impact of stabilization/solidification followed by landfilling. To study the stabilization of oxyanion forming elements and heavy metals during the production process, two series of experiments were performed. In the first series of experiments, the main pollutant, Mo was adsorbed onto iron-based adsorbents, which were then mixed with industrial sludge (3 w/w%) and heated at 1100°C for 30 min. Mo was chosen, as this element is easily adsorbed onto iron-based adsorbents and it is the element that is the most difficult to stabilize (i.e. the highest temperatures need to be reached before the concentrations in the leachate are reduced). Leaching concentration from the 97/3 sludge/adsorbent mixture before heating ranged between 85 and 154 mg/kg; after the heating process they were reduced to 0.42-1.48 mg/kg. Mo was actually stabilized, as the total Mo concentration after addition was not affected by the heat treatment. In the second series of experiments, the sludge was spiked with other heavy metals and oxyanion forming elements (Cr, Ni, Cu, Zn, As, Cd and Pb) in concentrations 5 times higher than the initial concentrations; after heat treatment the leachate concentrations were below the regulatory limit values. The incorporation of spent adsorbents in ceramic materials is a valuable and sustainable alternative to the existing treatment methods, saving raw materials in the ceramics production process and avoiding the use of stabilizing agents. Besides, spent adsorbents added to the raw material for ceramic products, may improve their aesthetic and structural properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Risk Mitigation in Preventing Adventitious Agent Contamination of Mammalian Cell Cultures.

PubMed

Shiratori, Masaru; Kiss, Robert

2017-11-14

Industrial-scale mammalian cell culture processes have been contaminated by viruses during the culturing phase. Although the historical frequency of such events has been quite low, the impact of contamination can be significant for the manufacturing company and for the supply of the product to patients. This chapter discusses sources of adventitious agent contamination risk in a cell culture process, provides a semiquantitative assessment of such risks, and describes potential process barriers that can be used to reduce contamination risk. High-temperature, short-time (HTST) heat treatment is recommended as the process barrier of choice, when compatible with the process. A case study assessing the compatibility of HTST heat treatment with a cell culture medium is presented, and lessons learned are shared from our experiences over many years of developing and implementing virus barriers in mammalian cell culture processes. Graphical Abstract.

Performance analysis of a solar still coupled with evacuated heat pipes

NASA Astrophysics Data System (ADS)

Pramod, B. V. N.; Prudhvi Raj, J.; Krishnan, S. S. Hari; Kotebavi, Vinod

2018-02-01

In developing countries the need for better quality drinking water is increasing steadily. We can overcome this need by using solar energy for desalination purpose. This process includes fabrication and analysis of a pyramid type solar still coupled with evacuated heat pipes. This experiment using evacuated heat pipes are carried in mainly three modes namely 1) Still alone 2) Using heat pipe with evacuated tubes 3)Using evacuated heat pipe. For this work single basin pyramid type solar still with 1m2 basin area is fabricated. Black stones and Black paint are utilised in solar still to increase evaporation rate of water in basin. The heat pipe’s evaporator section is placed inside evacuated tube and the heat pipe’s condenser section is connected directly to the pyramid type solar still’s lower portion. The output of distillate water from still with evacuated heat pipe is found to be 40% more than the still using only evacuated tubes.

Calibrated heat flow model for the determination of different heat-affected zones in single-pass laser-cut CFRP using a cw CO2 laser

NASA Astrophysics Data System (ADS)

Mucha, P.; Berger, P.; Weber, R.; Speker, N.; Sommer, B.; Graf, T.

2015-03-01

Laser machining has great potential for automated manufacturing of parts made of carbon-fiber-reinforced plastic (CFRP) due to the nearly force and tool-wear free processing. The high vaporization temperatures and the large heat conductivity of the carbon fibers, however, lead to unintentional heat conduction into the material causing damage in zones close to the process. In this paper, the matrix damage zone (MDZ) is subdivided into a matrix sublimation zone (MSZ) where the matrix material was sublimated and a zone where the temperature temporarily exceeded a value causing structural damage in the matrix. In order to investigate the extent of these zones, a one-dimensional heat flow model was applied, which was calibrated by cutting experiments using temperature sensors embedded in the CFRP samples. The investigations showed that the extents of the MSZ and MDZ are dominated by a total interaction time, which includes the passage of the laser beam and the continued interaction of the cloud of hot ablation products with the carbon fibers at the kerf wall and that from a practical point of view, the experimentally determined effective heat conductivity is suitable for simple estimations of the heat-affected zones in CFRP.

Experimental Studies of Heat-Transfer Behavior at a Casting/Water-Cooled-Mold Interface and Solution of the Heat-Transfer Coefficient

NASA Astrophysics Data System (ADS)

Zeng, Y. D.; Wang, F.

2018-02-01

In this paper, we propose an experimental model for forming an air gap at the casting/mold interface during the solidification process of the casting, with the size and formation time of the air gap able to be precisely and manually controlled. Based on this model, experiments of gravity casting were performed, and on the basis of the measured temperatures at different locations inside the casting and the mold, the inverse analysis method of heat transfer was applied to solve for the heat-transfer coefficient at the casting/mold interface during the solidification process. Furthermore, the impacts of the width and formation time of the air gap on the interface heat-transfer coefficient (IHTC) were analyzed. The results indicate that the experimental model succeeds in forming an air gap having a certain width at any moment during solidification of the casting, thus allowing us to conveniently and accurately study the impact of the air gap on IHTC using the model. In addition, the casting/mold IHTC is found to first rapidly decrease as the air gap forms and then slowly decrease as the solidification process continues. Moreover, as the width of the air gap and the formation time of the air gap increase, the IHTC decreases.

Theoretical and Experimental Investigation of the Stability of an Evaporating Constrained Vapor Bubble

NASA Technical Reports Server (NTRS)

Wayner, P. C., Jr.; Plawsky, J. L.; Wong, Harris

2004-01-01

The major accomplishments of the experimental portion of the research were documented in Ling Zheng's doctoral dissertation. Using Pentane, he obtained a considerable amount of data on the stability and heat transfer characteristics of an evaporating meniscus. The important points are that experimental equipment to obtain data on the stability and heat transfer characteristics of an evaporating meniscus were built and successfully operated. The data and subsequent analyses were accepted by the Journal of Heat Transfer for publication in 2004 [PU4]. The work was continued by a new graduate student using HFE-7000 [PU3] and then Pentane at lower heat fluxes. The Pentane results are being analyzed for publication. The experimental techniques are currently being used in our other NASA Grant. The oscillation of the contact line observed in the experiments involves evaporation (retraction part) and spreading. Since both processes occur with finite contact angles, it is important to derive a precise equation of the intermolecular forces (disjoining pressure) valid for non-zero contact angles. This theoretical derivation was accepted for publication by Journal of Fluid Mechanics [PU5]. The evaporation process near the contact line is complicated, and an idealized micro heat pipe has been proposed to help in elucidating the detailed evaporation process [manuscripts in preparation].

NASA-sponsored containerless processing experiments

NASA Technical Reports Server (NTRS)

Hofmeister, William H.

1990-01-01

An outline is presented of containerless processing and facilities at Intersonics which is sponsored by NASA. There are electromagnetic, acoustic, and aerodynamic levitation facilities. There are also laser beam and arc lamp heating systems along with state of the art noncontact temperature and optical property measurement facilities. Nonintrusive diagnostic techniques with Laser Induced Fluorescence and mass spectrometer are also available. Controlled atmosphere processing, gas quenching, and proven microgravity processing technology is part of the Intersonics capabilities.

[Steam and air co-injection in removing TCE in 2D-sand box].

PubMed

Wang, Ning; Peng, Sheng; Chen, Jia-Jun

2014-07-01

Steam and air co-injection is a newly developed and promising soil remediation technique for non-aqueous phase liquids (NAPLs) in vadose zone. In this study, in order to investigate the mechanism of the remediation process, trichloroethylene (TCE) removal using steam and air co-injection was carried out in a 2-dimensional sandbox with different layered sand structures. The results showed that co-injection perfectly improved the "tailing" effect compared to soil vapor extraction (SVE), and the remediation process of steam and air co-injection could be divided into SVE stage, steam strengthening stage and heat penetration stage. Removal ratio of the experiment with scattered contaminant area was higher and removal speed was faster. The removal ratios from the two experiments were 93.5% and 88.2%, and the removal periods were 83.9 min and 90.6 min, respectively. Steam strengthened the heat penetration stage. The temperature transition region was wider in the scattered NAPLs distribution experiment, which reduced the accumulation of TCE. Slight downward movement of TCE was observed in the experiment with TCE initially distributed in a fine sand zone. And such downward movement of TCE reduced the TCE removal ratio.

Direct Heating of a Laser-Imploded Core by Ultraintense Laser-Driven Ions

NASA Astrophysics Data System (ADS)

Kitagawa, Y.; Mori, Y.; Komeda, O.; Ishii, K.; Hanayama, R.; Fujita, K.; Okihara, S.; Sekine, T.; Satoh, N.; Kurita, T.; Takagi, M.; Watari, T.; Kawashima, T.; Kan, H.; Nishimura, Y.; Sunahara, A.; Sentoku, Y.; Nakamura, N.; Kondo, T.; Fujine, M.; Azuma, H.; Motohiro, T.; Hioki, T.; Kakeno, M.; Miura, E.; Arikawa, Y.; Nagai, T.; Abe, Y.; Ozaki, S.; Noda, A.

2015-05-01

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D (d ,n )He 3 -reacted neutrons (DD beam-fusion neutrons) with the yield of 5 ×108 n /4 π sr . Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6 ×107 n /4 π sr , raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g /cm3 in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g /cm3 ); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Direct heating of a laser-imploded core by ultraintense laser-driven ions.

PubMed

Kitagawa, Y; Mori, Y; Komeda, O; Ishii, K; Hanayama, R; Fujita, K; Okihara, S; Sekine, T; Satoh, N; Kurita, T; Takagi, M; Watari, T; Kawashima, T; Kan, H; Nishimura, Y; Sunahara, A; Sentoku, Y; Nakamura, N; Kondo, T; Fujine, M; Azuma, H; Motohiro, T; Hioki, T; Kakeno, M; Miura, E; Arikawa, Y; Nagai, T; Abe, Y; Ozaki, S; Noda, A

2015-05-15

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D(d,n)^{3}He-reacted neutrons (DD beam-fusion neutrons) with the yield of 5×10^{8} n/4π sr. Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6×10^{7} n/4π sr, raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g/cm^{3} in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g/cm^{3}); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Physical and Theoretical Models of Heat Pollution Applied to Cramped Conditions Welding Taking into Account the Different Types of Heat

NASA Astrophysics Data System (ADS)

Bulygin, Y. I.; Koronchik, D. A.; Legkonogikh, A. N.; Zharkova, M. G.; Azimova, N. N.

2017-05-01

The standard k-epsilon turbulence model, adapted for welding workshops, equipped with fixed workstations with sources of pollution took into account only the convective component of heat transfer, which is quite reasonable for large-volume rooms (with low density distribution of sources of pollution) especially the results of model calculations taking into account only the convective component correlated well with experimental data. For the purposes of this study, when we are dealing with a small confined space where necessary to take account of the body heated to a high temperature (for welding), located next to each other as additional sources of heat, it can no longer be neglected radiative heat exchange. In the task - to experimentally investigate the various types of heat transfer in a limited closed space for welding and behavior of a mathematical model, describing the contribution of the various components of the heat exchange, including radiation, influencing the formation of fields of concentration, temperature, air movement and thermal stress in the test environment. Conducted field experiments to model cubic body, allowing you to configure and debug the model of heat and mass transfer processes with the help of the developed approaches, comparing the measurement results of air flow velocity and temperature with the calculated data showed qualitative and quantitative agreement between process parameters, that is an indicator of the adequacy of heat and mass transfer model.

Optical/thermal analysis methodology for a space-qualifiable RTP furnace

NASA Technical Reports Server (NTRS)

Bugby, D.; Dardarian, S.; Cole, E.

1993-01-01

A methodology to predict the coupled optical/thermal performance of a reflective cavity heating system was developed and a laboratory test to verify the method was carried out. The procedure was utilized to design a rapid thermal processing (RTP) furnace for the Robot-Operated Material Processing in Space (ROMPS) Program which is a planned STS HH-G canister experiment involving robotics and material processing in microgravity. The laboratory test employed a tungsten-halogen reflector/lamp to heat thin, p-type silicon wafers. Measurements instrumentation consisted of 5-mil Pt/Pt-Rh thermocouples and an optical pyrometer. The predicted results, utilizing an optical ray-tracing program and a lumped-capacitance thermal analyzer, showed good agreement with the measured data for temperatures exceeding 1300 C.

Impact of heating method on the flocculation process using thermosensitive polymer.

PubMed

Lemanowicz, Marcin; Kuźnik, Wojciech; Gibas, Mirosław; Dzido, Grzegorz; Gierczycki, Andrzej

2012-09-01

The impact of suspension heating method on the flocculation process using thermosensitive polymer is reported in this paper. In experiments a model suspension of chalk in RO water (purified by Reverse Osmosis) was destabilized using a copolymer of N-isopropylacrylamide (NIPAM) and cationic diallyldimethyl ammonium chloride (DADMAC). The measurements were made using a laboratory setup consisting of a mixing tank with four baffles, Rushton turbine, laser particle sizer Analysette 22 by Fritsch and a system of pump and thermostating devices. Two different modes of heating were used. In the first case the temperature of the system was gently raised above the Lower Critical Solution Temperature (LCST) using an electrical heater placed inside the tank, while in the second case the system temperature was rapidly raised by an injection of hot water directly into the tank. It was proven that heating method as well as the polymer concentration was crucial to the shape and size of created flocs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modeling of Convective-Stratiform Precipitation Processes: Sensitivity to Partitioning Methods

NASA Technical Reports Server (NTRS)

Lang, S. E.; Tao, W.-K.; Simpson, J.; Ferrier, B.; Starr, David OC. (Technical Monitor)

2001-01-01

Six different convective-stratiform separation techniques, including a new technique that utilizes the ratio of vertical and terminal velocities, are compared and evaluated using two-dimensional numerical simulations of a tropical [Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment (TOGA COARE)] and midlatitude continental [Preliminary Regional Experiment for STORM-Central (PRESTORM)] squall line. Comparisons are made in terms of rainfall, cloud coverage, mass fluxes, apparent heating and moistening, mean hydrometeor profiles, CFADs (Contoured Frequency with Altitude Diagrams), microphysics, and latent heating retrieval. Overall, it was found that the different separation techniques produced results that qualitatively agreed. However, the quantitative differences were significant. Observational comparisons were unable to conclusively evaluate the performance of the techniques. Latent heating retrieval was shown to be sensitive to the use of separation technique mainly due to the stratiform region for methods that found very little stratiform rain.

Experimental test of liquid droplet radiator performance

NASA Astrophysics Data System (ADS)

Mattick, A. T.; Simon, M. A.

The liquid droplet radiator (LDR) is a heat rejection system for space power systems wherein an array of heated liquid droplets radiates energy directly to space. The use of submillimeter droplets provides large radiating area-to-mass ratio, resulting in radiator systems which are several times lighter than conventional solid surface radiators. An experiment is described in which the power radiated by an array of 2300 streams of silicone oil droplets is measured to test a previously developed theory of the LDR radiation process. This system would be capable of rejecting several kW of heat in space. Furthermore, it would be suitable as a modular unit of an LDR designed for 100-kW power levels. The experiment provided confirmation of the theoretical dependence of droplet array emissivity on optical depth. It also demonstrated the ability to create an array of more than 1000 droplet streams having a divergence less than 1 degree.

Experimental test of liquid droplet radiator performance

NASA Technical Reports Server (NTRS)

Mattick, A. T.; Simon, M. A.

1987-01-01

The liquid droplet radiator (LDR) is a heat rejection system for space power systems wherein an array of heated liquid droplets radiates energy directly to space. The use of submillimeter droplets provides large radiating area-to-mass ratio, resulting in radiator systems which are several times lighter than conventional solid surface radiators. An experiment is described in which the power radiated by an array of 2300 streams of silicone oil droplets is measured to test a previously developed theory of the LDR radiation process. This system would be capable of rejecting several kW of heat in space. Furthermore, it would be suitable as a modular unit of an LDR designed for 100-kW power levels. The experiment provided confirmation of the theoretical dependence of droplet array emissivity on optical depth. It also demonstrated the ability to create an array of more than 1000 droplet streams having a divergence less than 1 degree.

The effect of physical parameterizations and initial data on the numerical prediction of the President's Day cyclone

NASA Technical Reports Server (NTRS)

Atlas, R.

1984-01-01

Results are presented from a series of forecast experiments which were conducted to assess the importance of large-scale dynamical processes, diabatic heating, and initial data to the prediction of the President's Day cyclone. The synoptic situation and NMC model forecasts for this case are summarized, and the analysis/forecast system and experiments are described. The GLAS Model forecast from the GLAS analysis at 0000 GMT 18 February is found to have correctly predicted intense coastal cyclogenesis and heavy precipitation. A forecast with surface heat and moisture fluxes eliminated failed to predict any cyclogenesis while a similar forecast with only the surface moisture flux excluded showed weak development. Diabatic heating resulting from oceanic fluxes significantly contributed to the generation of low-level cyclonic vorticity and the intensification and slow rate of movement of an upper level ridge over the western Atlantic.

On buoyancy-driven natural ventilation of a room with a heated floor

NASA Astrophysics Data System (ADS)

Gladstone, Charlotte; Woods, Andrew W.

2001-08-01

The natural ventilation of a room, both with a heated floor and connected to a cold exterior through two openings, is investigated by combining quantitative models with analogue laboratory experiments. The heated floor generates an areal source of buoyancy while the openings allow displacement ventilation to operate. When combined, these produce a steady state in which the air in the room is well-mixed, and the heat provided by the floor equals the heat lost by displacement. We develop a quantitative model describing this process, in which the advective heat transfer through the openings is balanced with the heat flux supplied at the floor. This model is successfully tested with observations from small-scale analogue laboratory experiments. We compare our results with the steady-state flow associated with a point source of buoyancy: for a given applied heat flux, an areal source produces heated air of lower temperature but a greater volume flux of air circulates through the room. We generalize the model to account for the effects of (i) a cooled roof as well as a heated floor, and (ii) an external wind or temperature gradient. In the former case, the direction of the flow through the openings depends on the temperature of the exterior air relative to an averaged roof and floor temperature. In the latter case, the flow is either buoyancy dominated or wind dominated depending on the strength of the pressure associated with the wind. Furthermore, there is an intermediate multiple-solution regime in which either flow regime may develop.

Measurements of plasma sheath heat flux in the Alcator C-Mod divertor

NASA Astrophysics Data System (ADS)

Brunner, Dan; Labombard, Brian; Terry, Jim; Reinke, Matt

2010-11-01

Heat flux is one of the most important parameters controlling the lifetime of first-wall components in fusion experiments and reactors. The sheath heat flux coefficient (γ) is a parameter relating heat flux (from a plasma to a material surface) to the electron temperature and ion saturation current. Being such a simple expression for a kinetic process, it is of great interest to plasma edge fluid modelers. Under the assumptions of equal ion and electron temperatures, no secondary electron emission, and no net current to the surface the value of γ is approximately 7 [1]. Alcator C-Mod provides a unique opportunity among today's experiments to measure reactor-relevant heat fluxes (100's of MW/m^2 parallel to the magnetic field) in reactor-like divertor geometry. Motivated by the DoE 2010 joint milestone to measure heat flux footprints, the lower outer divertor of Alcator has been instrumented with a suite of Langmuir probes, novel surface thermocouples, and calorimeters in tiles purposefully ramped to eliminate shadowing; all within view of an IR camera. Initial results indicate that the experimentally inferred values of γ are found to agree with simple theory in the sheath limited regime and diverges to lower values as the density increases.

Improving the installation of renewable heating technology in UK social housing properties through user centred design.

PubMed

Moore, Natalie; Haines, Victoria; Lilley, Debra

2015-11-01

Social housing organisations are increasingly installing renewable energy technologies, particularly for the provision of heating and hot water. To meet carbon reduction targets, uptake and installation must allow occupants to use the technology effectively. This paper describes research which investigated the service of installing heat pumps into UK social housing properties, from both landlords' and tenants' experiences. Adopting a user centred design approach, the research was in three phases: an exploration study to investigate landlords' and tenants' experiences of heat pump installation and use; refinement and development of the requirements for improved service delivery, primarily technology introduction and control; and the development and initial evaluation of an information leaflet as a key touchpoint in the service delivery. Recommendations for improved service delivery, to enable heat pumps to be accepted and used more effectively, are presented, as well as reflection on the process of applying user centred design in this context. In a relatively immature area of industry, installations to date have been heavily focused on technical aspects. This paper provides an insight into the human aspects of the service delivery of heat pumps in social housing, providing designers and social housing landlords with insight about how to improve the service.

Improving the installation of renewable heating technology in UK social housing properties through user centred design

PubMed Central

Moore, Natalie; Lilley, Debra

2015-01-01

Social housing organisations are increasingly installing renewable energy technologies, particularly for the provision of heating and hot water. To meet carbon reduction targets, uptake and installation must allow occupants to use the technology effectively. This paper describes research which investigated the service of installing heat pumps into UK social housing properties, from both landlords’ and tenants’ experiences. Adopting a user centred design approach, the research was in three phases: an exploration study to investigate landlords’ and tenants’ experiences of heat pump installation and use; refinement and development of the requirements for improved service delivery, primarily technology introduction and control; and the development and initial evaluation of an information leaflet as a key touchpoint in the service delivery. Recommendations for improved service delivery, to enable heat pumps to be accepted and used more effectively, are presented, as well as reflection on the process of applying user centred design in this context. In a relatively immature area of industry, installations to date have been heavily focused on technical aspects. This paper provides an insight into the human aspects of the service delivery of heat pumps in social housing, providing designers and social housing landlords with insight about how to improve the service. PMID:26539060

Influence of mold surface temperature on polymer part warpage in rapid heat cycle molding

NASA Astrophysics Data System (ADS)

Berger, G. R.; Pacher, G. A.; Pichler, A.; Friesenbichler, W.; Gruber, D. P.

2014-05-01

Dynamic mold surface temperature control was examined for its influence on the warpage. A test mold, featuring two different rapid heat cycle molding (RHCM) technologies was used to manufacture complex plate-shaped parts having different ribs, varying thin-wall regions, and both, circular and rectangular cut-outs. The mold's nozzle side is equipped with the areal heating and cooling technology BFMOLD®, where the heating/cooling channels are replaced by a ball-filled slot near the cavity surface flooded through with hot and cold water sequentially. Two local electrical ceramic heating elements are installed into the mold's ejection side. Based on a 23 full-factorial design of experiments (DoE) plan, varying nozzle temperature (Tnozzle), rapid heat cycle molding temperature (TRHCM) and holding pressure (pn), specimens of POM were manufactured systematically. Five specimens were examined per DoE run. The resulting warpage was measured at 6 surface line scans per part using the non-contact confocal topography system FRT MicroProf®. Two warpage parameters were calculated, the curvature of a 2nd order approximation a, and the vertical deflection at the profile center d. Both, the influence strength and the acting direction of the process parameters and their interactions on a and d were calculated by statistical analysis. Linear mathematical process models were determined for a and d to predict the warpage as a function of the process parameter settings. Finally, an optimum process setting was predicted, based on the process models and Microsoft Excel GRG solver. Clear and significant influences of TRHCM, pn, Tnozzle, and the interaction of TRHCM and pn were determined. While TRHCM was dominant close to the gate, pn became more effective as the flow length increased.

Long-duration heat load measurement approach by novel apparatus design and highly efficient algorithm

NASA Astrophysics Data System (ADS)

Zhu, Yanwei; Yi, Fajun; Meng, Songhe; Zhuo, Lijun; Pan, Weizhen

2017-11-01

Improving the surface heat load measurement technique for vehicles in aerodynamic heating environments is imperative, regarding aspects of both the apparatus design and identification efficiency. A simple novel apparatus is designed for heat load identification, taking into account the lessons learned from several aerodynamic heating measurement devices. An inverse finite difference scheme (invFDM) for the apparatus is studied to identify its surface heat flux from the interior temperature measurements with high efficiency. A weighted piecewise regression filter is also proposed for temperature measurement prefiltering. Preliminary verification of the invFDM scheme and the filter is accomplished via numerical simulation experiments. Three specific pieces of apparatus have been concretely designed and fabricated using different sensing materials. The aerodynamic heating process is simulated by an inductively coupled plasma wind tunnel facility. The identification of surface temperature and heat flux from the temperature measurements is performed by invFDM. The results validate the high efficiency, reliability and feasibility of heat load measurements with different heat flux levels utilizing the designed apparatus and proposed method.

Validation of the Land-Surface Energy Budget and Planetary Boundary Layer for Several Intensive field Experiments

NASA Technical Reports Server (NTRS)

Bosilovich, Michael G.; Schubert, Siegfried; Molod, Andrea; Houser, Paul R.

1999-01-01

Land-surface processes in a data assimilation system influence the lower troposphere and must be properly represented. With the recent incorporation of the Mosaic Land-surface Model (LSM) into the GEOS Data Assimilation System (DAS), the detailed land-surface processes require strict validation. While global data sources can identify large-scale systematic biases at the monthly timescale, the diurnal cycle is difficult to validate. Moreover, global data sets rarely include variables such as evaporation, sensible heat and soil water. Intensive field experiments, on the other hand, can provide high temporal resolution energy budget and vertical profile data for sufficiently long periods, without global coverage. Here, we evaluate the GEOS DAS against several intensive field experiments. The field experiments are First ISLSCP Field Experiment (FIFE, Kansas, summer 1987), Cabauw (as used in PILPS, Netherlands, summer 1987), Atmospheric Radiation Measurement (ARM, Southern Great Plains, winter and summer 1998) and the Surface Heat Budget of the Arctic Ocean (SHEBA, Arctic ice sheet, winter and summer 1998). The sites provide complete surface energy budget data for periods of at least one year, and some periods of vertical profiles. This comparison provides a detailed validation of the Mosaic LSM within the GEOS DAS for a variety of climatologic and geographic conditions.

Three-dimensional modeling of diesel engine intake flow, combustion and emissions

NASA Technical Reports Server (NTRS)

Reitz, R. D.; Rutland, C. J.

1992-01-01

A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation, and the intake flow process. Improved and/or new submodels which were completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and finally, the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To date, comparisons with measured engine cylinder pressure and heat flux data were made for homogeneous charge, spark-ignited and compression-ignited engines. The model results are in good agreement with the experiments.

Optimizing an ELF/VLF Phased Array at HAARP

NASA Astrophysics Data System (ADS)

Fujimaru, S.; Moore, R. C.

2013-12-01

The goal of this study is to maximize the amplitude of 1-5 kHz ELF/VLF waves generated by ionospheric HF heating and measured at a ground-based ELF/VLF receiver. The optimization makes use of experimental observations performed during ELF/VLF wave generation experiments at the High-frequency Active Auroral Research Program (HAARP) Observatory in Gakona, Alaska. During these experiments, the amplitude, phase, and propagation delay of the ELF/VLF waves were carefully measured. The HF beam was aimed at 15 degrees zenith angle in 8 different azimuthal directions, equally spaced in a circle, while broadcasting a 3.25 MHz (X-mode) signal that was amplitude modulated (square wave) with a linear frequency-time chirp between 1 and 5 kHz. The experimental observations are used to provide reference amplitudes, phases, and propagation delays for ELF/VLF waves generated at these specific locations. The presented optimization accounts for the trade-off between duty cycle, heated area, and the distributed nature of the source region in order to construct a "most efficient" phased array. The amplitudes and phases generated by modulated heating at each location are combined in post-processing to find an optimal combination of duty cycle, heating location, and heating order.

Utilization of Aluminum Waste with Hydrogen and Heat Generation

NASA Astrophysics Data System (ADS)

Buryakovskaya, O. A.; Meshkov, E. A.; Vlaskin, M. S.; Shkolnokov, E. I.; Zhuk, A. Z.

2017-10-01

A concept of energy generation via hydrogen and heat production from aluminum containing wastes is proposed. The hydrogen obtained by oxidation reaction between aluminum waste and aqueous solutions can be supplied to fuel cells and/or infrared heaters for electricity or heat generation in the region of waste recycling. The heat released during the reaction also can be effectively used. The proposed method of aluminum waste recycling may represent a promising and cost-effective solution in cases when waste transportation to recycling plants involves significant financial losses (e.g. remote areas). Experiments with mechanically dispersed aluminum cans demonstrated that the reaction rate in alkaline solution is high enough for practical use of the oxidation process. In theexperiments aluminum oxidation proceeds without any additional aluminum activation.

Fault Lubrication and Earthquake Propagation in Thermally Unstable Rocks

NASA Astrophysics Data System (ADS)

de Paola, Nicola; Hirose, Takehiro; Mitchell, Tom; di Toro, Giulio; Viti, Cecilia; Shimamoto, Toshiko

2010-05-01

During earthquake propagation in thermally unstable rocks, the frictional heat generated can induce thermal reactions which lead to chemical and physical changes in the slip zone. We performed laboratory friction experiments on thermally unstable minerals (gypsum, dolomite and calcite) at about 1 m/s slip velocities, more than 1 m displacements and calculated temperature rise above 500 C degrees. These conditions are typical during the propagation of large earthquakes. The main findings of our experimental work are: 1) Dramatic fault weakening is characterized by a dynamic frictional strength drop up to 90% of the initial static value in the Byerlee's range. 2) Seismic source parameters, calculated from our experimental results, match those obtained by modelling of seismological data from the 1997 Cofliorito earthquake nucleated in carbonate rocks in Italy (i.e. same rocks used in the friction experiments). Fault lubrication observed during the experiments is controlled by the superposition of multiple, thermally-activated, slip weakening mechanisms (e.g., flash heating, thermal pressurization and nanoparticle lubrication). The integration of mechanical and CO2 emission data, temperature rise calculations and XRPD analyses suggests that flash heating is not the main dynamic slip weakening process. This process was likely inhibited very soon (t < 1s) for displacements d < 0.20 m, when intense grain size reduction by both cataclastic and chemical/thermal processes took place. Conversely, most of the dynamic weakening observed was controlled by thermal pressurization and nanoparticle lubrication processes. The dynamic shear strength of experimental faults was reduced when fluids (CO2, H2O) were trapped and pressurized within the slip zone, in accord with the effective normal stress principle. The fluids were not initially present in the slip zone, but were released by decarbonation (dolomite and Mg-rich calcite) and dehydration (gypsum) reactions, both activated by frictional heating during seismic slip. The dynamic weakening effects of nanoparticles (e.g. powder lubrication) are still unclear due to the poorly understood mechanical properties of nanoparticles at high velocities and temperatures, typical of seismic slip. The experimental results improve our understanding of the controls exerted on the dynamic frictional strength of faults by the coseismic operation of chemical (mineral decomposition) and physical (grain size reduction, fluids release and pressurization) processes. The estimation of this parameter is out of the range of seismological studies, although it controls the magnitude of the stress drop, the seismic fault heat flow and the relative partitioning of the earthquake energy budget, which are all controversial and still debated issues in the scientific community.

Fault Lubrication and Earthquake Propagation in Thermally Unstable Rocks

NASA Astrophysics Data System (ADS)

de Paola, N.; Hirose, T.; Mitchell, T. M.; di Toro, G.; Viti, C.; Shimamoto, T.

2009-12-01

During earthquake propagation in thermally unstable rocks, the frictional heat generated can induce thermal reactions which lead to chemical and physical changes in the slip zone. We performed laboratory friction experiments on thermally unstable minerals (gypsum, dolomite and calcite) at about 1 m/s slip velocities, more than 1 m displacements and calculated temperature rise above 500 C degrees. These conditions are typical during the propagation of large earthquakes. The main findings of our experimental work are: 1) Dramatic fault weakening is characterized by a dynamic frictional strength drop up to 90% of the initial static value in the Byerlee’s range. 2) Seismic source parameters, calculated from our experimental results, match those obtained by modelling of seismological data from the 1997 Cofliorito earthquake nucleated in carbonate rocks in Italy (i.e. same rocks used in the friction experiments). Fault lubrication observed during the experiments is controlled by the superposition of multiple, thermally-activated, slip weakening mechanisms (e.g., flash heating, thermal pressurization and nanoparticle lubrication). The integration of mechanical and CO2 emission data, temperature rise calculations and XRPD analyses suggests that flash heating is not the main dynamic slip weakening process. This process was likely inhibited very soon (t < 1s) for displacements d < 0.20 m, when intense grain size reduction by both cataclastic and chemical/thermal processes took place. Conversely, most of the dynamic weakening observed was controlled by thermal pressurization and nanoparticle lubrication processes. The dynamic shear strength of experimental faults was reduced when fluids (CO2, H2O) were trapped and pressurized within the slip zone, in accord with the effective normal stress principle. The fluids were not initially present in the slip zone, but were released by decarbonation (dolomite and Mg-rich calcite) and dehydration (gypsum) reactions, both activated by frictional heating during seismic slip. The dynamic weakening effects of nanoparticles (e.g. powder lubrication) are still unclear due to the poorly understood mechanical properties of nanoparticles at high velocities and temperatures, typical of seismic slip. The experimental results improve our understanding of the controls exerted on the dynamic frictional strength of faults by the coseismic operation of chemical (mineral decomposition) and physical (grain size reduction, fluids release and pressurization) processes. The estimation of this parameter is out of the range of seismological studies, although it controls the magnitude of the stress drop, the seismic fault heat flow and the relative partitioning of the earthquake energy budget, which are all controversial and still debated issues in the scientific community.

Effects of Gravity on Processing Heavy Metal Fluoride Fibers

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

1997-01-01

The effects of gravity on the crystal nucleation of heavy metal fluoride fibers have been studied in preliminary experiments utilizing NASA's KC-135 reduced gravity aircraft and a microgravity sounding rocket flight. Commercially produced fibers were heated to the crystallization temperature in normal and reduced gravity. The fibers processed in normal gravity showed complete crystallization while the fibers processed in reduced gravity did not show signs of crystallization.

Wind and Wind Stress Measurements in HiRes

DTIC Science & Technology

2008-09-30

to design the experimental system to be conducted on R /P FLIP. Data from a past experiment are also being analyzed with respect to processes...For the HiRes experiment on R /P FLIP, the air temperature profile will be measured along with wind stress, surface heat flux, sea surface...the best as it registered the lower ambient temperature. In preparation for the HiRes experiment onboard R /P FLIP a mast prototype was built in

[Microwave thermal remediation of soil contaminated with crude oil enhanced by granular activated carbon].

PubMed

Li, Da-Wei; Zhang, Yao-Bin; Quan, Xie; Zhao, Ya-Zhi

2009-02-15

The advantage of rapid, selective and simultaneous heating of microwave heating technology was taken to remediate the crude oil-contaminated soil rapidly and to recover the oil contaminant efficiently. The contaminated soil was processed in the microwave field with addition of granular activated carbon (GAC), which was used as strong microwave absorber to enhance microwave heating of the soil mixture to remove the oil contaminant and recover it by a condensation system. The influences of some process parameters on the removal of the oil contaminant and the oil recovery in the remediation process were investigated. The results revealed that, under the condition of 10.0% GAC, 800 W microwave power, 0.08 MPa absolute pressure and 150 mL x min(-1) carrier gas (N2) flow-rate, more than 99% oil removal could be obtained within 15 min using this microwave thermal remediation enhanced by GAC; at the same time, about 91% of the oil contaminant could be recovered without significant changes in chemical composition. In addition, the experiment results showed that GAC can be reused in enhancing microwave heating of soil without changing its enhancement efficiency obviously.

Numerical investigation for formability of aluminum 6016 alloy under non-isothermal warm forming process

NASA Astrophysics Data System (ADS)

Hu, P.; Dai, M. H.; Ying, L.; Shi, D. Y.; Zhao, K. M.; Lu, J. D.

2013-05-01

The warm forming technology of aluminum alloy has attracted attention from worldwide automotive engineering sector in recent years, with which the complex geometry parts can be realized at elevated temperature. A non-isothermal warm forming process for the heat treatable aluminum can quickly carry out its application on traditional production line by adding a furnace to heat up the aluminum alloy sheet. The 6000 aluminum alloy was investigated by numerical simulation and experiment using the Nakajima test model in this paper. A modified Fields-Backofen model was introduced into numerical simulation process to describe the thermo-mechanical flow behavior of a 6000 series aluminum alloy. The experimental data was obtained by conducting thermal-mechanical uniaxial tensile experiment in temperatures range of 25˜400°C to guarantee the numerical simulation more accurate. The numerical simulation was implemented with LS_DYNA software in terms of coupled dynamic explicit method for investigating the effect of initial forming temperature and the Binder Holder Force (BHF), which are critical process parameters in non-isothermal warm forming. The results showed that the optimal initial forming temperature range was 300°C˜350°C. By means of conducting numerical simulation in deep drawing box model, the forming window of BHF and temperature around the optimal initial forming temperature (275°, 300° and 325°) are investigated, which can provide guidance to actual experiment.

Development of a Hybrid Deep Drawing Process to Reduce Springback of AHSS

NASA Astrophysics Data System (ADS)

Boskovic, Vladimir; Sommitsch, Christoph; Kicin, Mustafa

2017-09-01

In future, the steel manufacturers will strive for the implementation of Advanced High Strength Steels (AHSS) in the automotive industry to reduce mass and improve structural performance. A key challenge is the definition of optimal and cost effective processes as well as solutions to introduce complex steel products in cold forming. However, the application of these AHSS often leads to formability problems such as springback. One promising approach in order to minimize springback is the relaxation of stress through the targeted heating of materials in the radius area after the deep drawing process. In this study, experiments are conducted on a Dual Phase (DP) and TWining Induced Plasticity (TWIP) steel for the process feasibility study. This work analyses the influence of various heat treatment temperatures on the springback reduction of deep drawn AHSS.

Optical droplet vaporization of nanoparticle-loaded stimuli-responsive microbubbles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Si, Ting; Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210; Li, Guangbin

2016-03-14

A capillary co-flow focusing process is developed to generate stimuli-responsive microbubbles (SRMs) that comprise perfluorocarbon (PFC) suspension of silver nanoparticles (SNPs) in a lipid shell. Upon continuous laser irradiation at around their surface plasmon resonance band, the SNPs effectively absorb electromagnetic energy, induce heat accumulation in SRMs, trigger PFC vaporization, and eventually lead to thermal expansion and fragmentation of the SRMs. This optical droplet vaporization (ODV) process is further simulated by a theoretical model that combines heat generation of SNPs, phase change of PFC, and thermal expansion of SRMs. The model is validated by benchtop experiments, where the ODV processmore » is monitored by microscopic imaging. The effects of primary process parameters on behaviors of ODV are predicted by the theoretical model, indicating the technical feasibility for process control and optimization in future drug delivery applications.« less

Nucleate pool boiling in subcooled liquid under microgravity: Results of TEXUS experimental investigations

NASA Astrophysics Data System (ADS)

Zell, M.; Straub, J.; Weinzierl, A.

1984-12-01

Experiments on subcooled nucleate pool boiling in microgravity were carried out to separate gravity driven effects on heat transfer within the boiling process. A ballistic trajectory by sounding rocket flight (TEXUS 5 and 10) achieved a gravity level of a/g = 0.0001 for 360 sec. For determination of geometrical effects on heat transport two different experimental configurations (platinum wire and flat plate) were employed. Boiling curves and bubble dynamics recorded by cinematography lead to gravity independent modelling of the boiling phenomena. The results ensure the applicability and high efficiency of nucleate pool boiling for heat exchangers in space laboratories.

Development Unit Configuration and Current Status of the MIP/MAAC Experiment

NASA Technical Reports Server (NTRS)

Karlmann, P. B.; Johnson, K. R.; Rapp, D.; Wu, J. J.

1999-01-01

The Mars In-Situ Propellant Production (ISPP) Precursor (MIP) experiment package is planned for inclusion on the Mars 2001 Lander. This experiment package consists of five experiments whose purpose is to demonstrate the performance of various ISPP processes in-situ on Mars. The demonstrated ability to produce propellant for Mars Return Vehicles (MRV) is considered to be a necessary precursor to any future manned mission to Mars. The Mars Atmosphere Acquisition and Compression (MAAC) experiment is part of the MIP package and is intended to demonstrate that, by using a sorption compressor, CO2 can be preferentially adsorbed at about 6 torr from the Mars atmosphere during the night when the bed is cold then subsequently compressed to about 800 torr by heating the bed and desorbing CO2 during the day. The compressed CO2 produced by MAAC is to be fed to the Oxygen Generator Subsystem (OGS) where pure oxygen is to be produced. Pure oxygen is considered to be one of the primary constituents of a future manned MRV propellant system. A MAAC Development Unit (DU) has been fabricated and tested at JPL. The MAAC DU consists of 1) a sorption bed filled with a CO2 selective sorbent material, 2) a purge system to be used to periodically backflush non-CO2 gases from the sorbent bed during adsorption, 3) a JPL-developed gas-gap heat switch that allows heat transfer to a radiator for heat removal from the bed during the night time adsorption period and that impedes heat transfer during the day time desorption period, 4) a radiator to radiate heat to the night sky during the adsorption period, 5) a set of three isolation valves and connecting tubing. 6) two pressure transducers and several thermocouples for monitoring the MAAC operating conditions, and command and data handling electronics. This paper will describe the operational theory and the configuration of the MAAC DU and will discuss the current status of the MAAC experiment development including some selected results of performance testing that has been completed prior to the ISRU III meeting.

Development Unit Configuration Status of the MIP/MAAC Experiment

NASA Technical Reports Server (NTRS)

Karlmann, P. B.; Johnson, K. R.; Rapp, D.; Wu, J. J.

1999-01-01

The Mars In-Situ Propellant Production (ISPP) Precursor (MIP) experiment package is planned for inclusion on the Mars 2001 Lander. This experiment package consists of five experiments whose purpose is to demonstrate the performance of various ISPP processes in-situ on Mars. The demonstrated ability to produce propellant for Mars Return Vehicles (MRV) is considered to be a necessary precursor to any future manned mission to Mars. The Mars Atmosphere Acquisition and Compression (MAAC) experiment is part of the MIP package and is intended to demonstrate that, by using a sorption compressor, CO2 can be preferentially adsorbed at about 6 torr from the Mars atmosphere during the night when the bed is cold then subsequently compressed to about 800 torr by heating the bed and desorbing C02 during the day. The compressed CO2 produced by MAAC is to be fed to the Oxygen Generator Subsystem (OGS) where pure oxygen is to be produced. Pure oxygen is considered to be one of the primary constituents of a future manned MRV propellant system. A MAAC Development Unit (DU) has been fabricated and tested at JPL. The MAAC DU consists of: (1) a sorption bed filled with a CO2 selective sorbent material; (2) a purge system to be used to periodically backflush non-CO2 gases from the sorbent bed during adsorption; (3) a JPL-developed gas-gap heat switch that allows heat transfer to a radiator for heat removal from the bed during the night time adsorption period and that impedes heat transfer during the day time desorption period; (4) a radiator to radiate heat to the night sky during the adsorption period; (5) a set of three isolation valves and connecting tubing; (6) two pressure transducers and several thermocouples for monitoring the MAAC operating conditions, and command and data handling electronics. This paper will describe the operational theory and the configuration of the MAAC DU and will discuss the current status of the MAAC experiment development including some selected results of performance testing that has been completed prior to the ISRU III meeting.

Transition process leading to microbubble emission boiling on horizontal circular heated surface in subcooled pool

NASA Astrophysics Data System (ADS)

Ueno, Ichiro; Ando, Jun; Horiuchi, Kazuna; Saiki, Takahito; Kaneko, Toshihiro

2016-11-01

Microbubble emission boiling (MEB) produces a higher heat flux than critical heat flux (CHF) and therefore has been investigated in terms of its heat transfer characteristics as well as the conditions under which MEB occurs. Its physical mechanism, however, is not yet clearly understood. We carried out a series of experiments to examine boiling on horizontal circular heated surfaces of 5 mm and of 10 mm in diameter, in a subcooled pool, paying close attention to the transition process to MEB. High-speed observation results show that, in the MEB regime, the growth, condensation, and collapse of the vapor bubbles occur within a very short time. In addition, a number of fine bubbles are emitted from the collapse of the vapor bubbles. By tracking these tiny bubbles, we clearly visualize that the collapse of the vapor bubbles drives the liquid near the bubbles towards the heated surface, such that the convection field around the vapor bubbles under MEB significantly differs from that under nucleate boiling. Moreover, the axial temperature gradient in a heated block (quasi-heat flux) indicates a clear difference between nucleate boiling and MEB. A combination of quasi-heat flux and the measurement of the behavior of the vapor bubbles allows us to discuss the transition to MEB. This work was financially supported by the 45th Research Grant in Natural Sciences from The Mitsubishi Foundation (2014 - 2015), and by Research Grant for Boiler and Pressurized Vessels from The Japan Boiler Association (2016).

Impact of Electromagnetic Field upon Temperature Measurement of Induction Heated Charges

NASA Astrophysics Data System (ADS)

Smalcerz, A.; Przylucki, R.

2013-04-01

The use of thermoelements is a commonly applied method in industry and engineering. It provides a wide measurement range of temperature, a direct voltage signal from the transducer, low cost of the thermoelement, and its resistance to many unfavorable factors which occur in an industrial environment. Unfortunately, thermoelements may not be resistant to interferences of a strong electromagnetic field because of the nature and design of a transducer. Induction heating is the most commonly used type of heating, at present, for metals. In order to guarantee the correctness of the carried out heating process, it is essential to control the temperature of the heated element. The impact of a strong electromagnetic field upon the thermocouple temperature measurement of the inductively heated elements has been analyzed in this paper. The experiment includes dozens of measurements where the following parameters have been varied: frequency of the current which feeds the heating inductor, power supplied to the heating system, geometry of heat inductor, and the charge material and its geometrical dimensions. Interferences of the power-line frequency have been eliminated in part of the carried out measurements.

Thermal modifications of root transparency and implications for aging: a pilot study.

PubMed

Gibelli, Daniele; De Angelis, Danilo; Rossetti, Francesca; Cappella, Annalisa; Frustaci, Michela; Magli, Francesca; Mazzarelli, Debora; Mazzucchi, Alessandra; Cattaneo, Cristina

2014-01-01

Root transparency has proven to be related to age and has been considered by different odontological methods for age estimation. Very little is known concerning possible variations of root transparency with heat, although the applicability of the method to burnt remains depends on the possible modifications of this specific variable. This pilot study presents the results of an experiment performed on 105 teeth obtained from dental patients and autopsy material, heated in an industrial oven at 50°C, 100°C, 150°C and 200°C. Root transparency was measured before and after the charring experiment. The heating process proved to radically modify root transparency, which decreased in 20% of samples at 50°C, in 34.6% at 100°C, in 50% at 150°C, in 77% at 200°C. The overall correlation index (CI) between decrease in root transparency and increase in temperature amounted to 0.96. These results show that heat may modify root transparency and suggest caution in using methods based on root transparency for age estimation. © 2013 American Academy of Forensic Sciences.

On computational experiments in some inverse problems of heat and mass transfer

NASA Astrophysics Data System (ADS)

Bilchenko, G. G.; Bilchenko, N. G.

2016-11-01

The results of mathematical modeling of effective heat and mass transfer on hypersonic aircraft permeable surfaces are considered. The physic-chemical processes (the dissociation and the ionization) in laminar boundary layer of compressible gas are appreciated. Some algorithms of control restoration are suggested for the interpolation and approximation statements of heat and mass transfer inverse problems. The differences between the methods applied for the problem solutions search for these statements are discussed. Both the algorithms are realized as programs. Many computational experiments were accomplished with the use of these programs. The parameters of boundary layer obtained by means of the A.A.Dorodnicyn's generalized integral relations method from solving the direct problems have been used to obtain the inverse problems solutions. Two types of blowing laws restoration for the inverse problem in interpolation statement are presented as the examples. The influence of the temperature factor on the blowing restoration is investigated. The different character of sensitivity of controllable parameters (the local heat flow and local tangent friction) respectively to step (discrete) changing of control (the blowing) and the switching point position is studied.

Application of response surface methodology for optimization of parameters for microwave heating of rare earth carbonates

NASA Astrophysics Data System (ADS)

Yin, Shaohua; Lin, Guo; Li, Shiwei; Peng, Jinhui; Zhang, Libo

2016-09-01

Microwave heating has been applied in the field of drying rare earth carbonates to improve drying efficiency and reduce energy consumption. The effects of power density, material thickness and drying time on the weight reduction (WR) are studied using response surface methodology (RSM). The results show that RSM is feasible to describe the relationship between the independent variables and weight reduction. Based on the analysis of variance (ANOVA), the model is in accordance with the experimental data. The optimum experiment conditions are power density 6 w/g, material thickness 15 mm and drying time 15 min, resulting in an experimental weight reduction of 73%. Comparative experiments show that microwave drying has the advantages of rapid dehydration and energy conservation. Particle analysis shows that the size distribution of rare earth carbonates after microwave drying is more even than those in an oven. Based on these findings, microwave heating technology has an important meaning to energy-saving and improvement of production efficiency for rare earth smelting enterprises and is a green heating process.

Enhanced heat transfer is dependent on thickness of graphene films: the heat dissipation during boiling

PubMed Central

Ahn, Ho Seon; Kim, Jin Man; Kim, TaeJoo; Park, Su Cheong; Kim, Ji Min; Park, Youngjae; Yu, Dong In; Hwang, Kyoung Won; Jo, HangJin; Park, Hyun Sun; Kim, Hyungdae; Kim, Moo Hwan

2014-01-01

Boiling heat transfer (BHT) is a particularly efficient heat transport method because of the latent heat associated with the process. However, the efficiency of BHT decreases significantly with increasing wall temperature when the critical heat flux (CHF) is reached. Graphene has received much recent research attention for applications in thermal engineering due to its large thermal conductivity. In this study, graphene films of various thicknesses were deposited on a heated surface, and enhancements of BHT and CHF were investigated via pool-boiling experiments. In contrast to the well-known surface effects, including improved wettability and liquid spreading due to micron- and nanometer-scale structures, nanometer-scale folded edges of graphene films provided a clue of BHT improvement and only the thermal conductivity of the graphene layer could explain the dependence of the CHF on the thickness. The large thermal conductivity of the graphene films inhibited the formation of hot spots, thereby increasing the CHF. Finally, the provided empirical model could be suitable for prediction of CHF. PMID:25182076

Condensation on Highly Superheated Surfaces: Unstable Thin Films in a Wickless Heat Pipe

NASA Astrophysics Data System (ADS)

Kundan, Akshay; Nguyen, Thao T. T.; Plawsky, Joel L.; Wayner, Peter C.; Chao, David F.; Sicker, Ronald J.

2017-03-01

A wickless heat pipe was operated on the International Space Station to provide a better understanding of how the microgravity environment might alter the physical and interfacial forces driving evaporation and condensation. Traditional heat pipes are divided into three zones: evaporation at the heated end, condensation at the cooled end, and intermediate or adiabatic in between. The microgravity experiments reported herein show that the situation may be dramatically more complicated. Beyond a threshold heat input, there was a transition from evaporation at the heated end to large-scale condensation, even as surface temperatures exceeded the boiling point by 160 K. The hotter the surface, the more vapor was condensed onto it. The condensation process at the heated end is initiated by thickness and temperature disturbances in the thin liquid film that wet the solid surface. Those disturbances effectively leave the vapor "superheated" in that region. Condensation is amplified and sustained by the high Marangoni stresses that exist near the heater and that drive liquid to cooler regions of the device.

Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangers

NASA Astrophysics Data System (ADS)

Taler, Dawid; Sury, Adam

2011-12-01

The aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.

Coarsening Kinetics and Morphological Evolution in a Two-Phase Titanium Alloy During Heat Treatment

NASA Astrophysics Data System (ADS)

Xu, Jianwei; Zeng, Weidong; Jia, Zhiqiang; Sun, Xin; Zhao, Yawei

2016-03-01

The effects of alpha/beta heat treatment on microstructure evolution of Ti-17 alloy with a lamellar colony structure are established. Heat treatment experiments are conducted at 1103 or 1063 K for times ranging from 10 min to 8 h. The main features of microstructure evolution during heat treatment comprise static globularization and coarsening of primary alpha phase. Such behaviors can be accelerated by higher heat treatment temperature. Furthermore, globularization and coarsening behaviors show a faster rate at higher prestrain. In order to better understand the microstructure evolution of Ti-17 alloy during alpha/beta heat treatment, static globularization and coarsening behaviors are modeled in the theoretical frame of the Johnson-Mehl-Avarmi-Kolmogorov (JMAK) and Lifshitz-Slyozov-Wagner (LSW) theories, respectively. The JMAK and LSW kinetics parameters are derived under different experimental conditions. Agreements between measurements and predictions are found, indicating that the JMAK and LSW theories can be used to predict and trace static globularization and coarsening processes of Ti-17 alloy during alpha/beta heat treatment.

A hot-cracking mitigation technique for welding high-strength aluminum alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Y.P.; Dong, P.; Zhang, J.

2000-01-01

A hot-cracking mitigation technique for gas tungsten arc welding (GTAW) of high-strength aluminum alloy 2024 is presented. The proposed welding technique incorporates a trailing heat sink (an intense cooling source) with respect to the welding torch. The development of the mitigation technique was based on both detailed welding process simulation using advanced finite element techniques and systematic laboratory experiments. The finite element methods were used to investigate the detailed thermomechanical behavior of the weld metal that undergoes the brittle temperature range (BTR) during welding. As expected, a tensile deformation zone within the material BTR region was identified behind the weldmore » pool under conventional GTA welding process conventional GTA welding process conditions for the aluminum alloy studied. To mitigate hot cracking, the tensile zone behind the weld pool must be eliminated or reduce to a satisfactory level if the weld metal hot ductility cannot be further improved. With detailed computational modeling, it was found that by the introduction of a trailing heat sink at some distance behind the welding arc, the tensile strain rate with respect to temperature in the zone encompassing the BTR region can be significantly reduced. A series of parametric studies were also conducted to derive optimal process parameters for the trailing heat sink. The experimental results confirmed the effectiveness of the trailing heat sink technique. With a proper implementation of the trailing heat sink method, hot cracking can be completely eliminated in welding aluminum alloy 2024 (AA 2024).« less

ERTS-C (Landsat 3) cryogenic heat pipe experiment definition

NASA Technical Reports Server (NTRS)

Brennan, P. J.; Kroliczek, E. J.

1975-01-01

A flight experiment designed to demonstrate current cryogenic heat pipe technology was defined and evaluated. The experiment package developed is specifically configured for flight aboard an ERTS type spacecraft. Two types of heat pipes were included as part of the experiment package: a transporter heat pipe and a thermal diode heat pipe. Each was tested in various operating modes. Performance data obtained from the experiment are applicable to the design of cryogenic systems for detector cooling, including applications where periodic high cooler temperatures are experienced as a result of cyclic energy inputs.

A Preliminary Report on the Strength and Metallography of a Bimetallic Friction Stir Weld Joint Between AA6061 and MIL-DTL-46100E High Hardness Steel Armor

DTIC Science & Technology

2012-11-26

alloy and High Hardness steel armor (MIL- STD-46100) were successfully joined by the friction stir welding (FSW) process using a tungsten- rhenium ...tungsten- rhenium stir tool. Process parameter variation experiments, which included inductive pre-heating, tool design geometry, plunge and traverse

Molecular Mechanisms Contributing to the Growth and Physiology of an Extremophile Cultured with Dielectric Heating

PubMed Central

Cusick, Kathleen D.; Lin, Baochuan; Malanoski, Anthony P.; Strycharz-Glaven, Sarah M.; Cockrell-Zugell, Allison; Fitzgerald, Lisa A.; Cramer, Jeffrey A.; Barlow, Daniel E.; Boyd, Thomas J.

2016-01-01

ABSTRACT The effect of microwave frequency electromagnetic fields on living microorganisms is an active and highly contested area of research. One of the major drawbacks to using mesophilic organisms to study microwave radiation effects is the unavoidable heating of the organism, which has limited the scale (<5 ml) and duration (<1 h) of experiments. However, the negative effects of heating a mesophile can be mitigated by employing thermophiles (organisms able to grow at temperatures of >60°C). This study identified changes in global gene expression profiles during the growth of Thermus scotoductus SA-01 at 65°C using dielectric (2.45 GHz, i.e., microwave) heating. RNA sequencing was performed on cultures at 8, 14, and 24 h after inoculation to determine the molecular mechanisms contributing to long-term cellular growth and survival under microwave heating conditions. Over the course of growth, genes associated with amino acid metabolism, carbohydrate metabolism, and defense mechanisms were upregulated; the number of repressed genes with unknown function increased; and at all time points, transposases were upregulated. Genes involved in cell wall biogenesis and elongation were also upregulated, consistent with the distinct elongated cell morphology observed after 24 h using microwave heating. Analysis of the global differential gene expression data enabled the identification of molecular processes specific to the response of T. scotoductus SA-01 to dielectric heating during growth. IMPORTANCE The residual heating of living organisms in the microwave region of the electromagnetic spectrum has complicated the identification of radiation-only effects using microorganisms for 50 years. A majority of the previous experiments used either mature cells or short exposure times with low-energy high-frequency radiation. Using global differential gene expression data, we identified molecular processes unique to dielectric heating using Thermus scotoductus SA-01 cultured over 30 h in a commercial microwave digestor. Genes associated with amino acid metabolism, carbohydrate metabolism, and defense mechanisms were upregulated; the number of repressed genes with unknown function increased; and at all time points, transposases were upregulated. These findings serve as a platform for future studies with mesophiles in order to better understand the response of microorganisms to microwave radiation. PMID:27520819

Improved silicon nitride for advanced heat engines

NASA Technical Reports Server (NTRS)

Yeh, Harry C.; Fang, Ho T.

1991-01-01

The results of a four year program to improve the strength and reliability of injection-molded silicon nitride are summarized. Statistically designed processing experiments were performed to identify and optimize critical processing parameters and compositions. Process improvements were monitored by strength testing at room and elevated temperatures, and microstructural characterization by optical, scanning electron microscopes, and scanning transmission electron microscope. Processing modifications resulted in a 20 percent strength and 72 percent Weibull slope improvement of the baseline material. Additional sintering aids screening and optimization experiments succeeded in developing a new composition (GN-10) capable of 581.2 MPa at 1399 C. A SiC whisker toughened composite using this material as a matrix achieved a room temperature toughness of 6.9 MPa m(exp .5) by the Chevron notched bar technique. Exploratory experiments were conducted on injection molding of turbocharger rotors.

The kinetics of reaction of the by-products of ablative materials at high temperatures and the rate of heat transfer between hot surfaces and reactive gases

NASA Technical Reports Server (NTRS)

Spokes, G. N.; Beadle, P. C.; Gac, N. A.; Golden, D. M.; King, K. D.; Benson, S. W.

1971-01-01

Research has been conducted by means of laboratory experiments to enhance understanding of the fundamental mechanisms of heterogeneous and homogeneous chemical reactions taking place during ablative processes that accompany the reentry or manned space vehicles into planetary atmospheres. Fundamental mechanisms of those chemical reactions believed to be important in the thermal degradation of ablative plastic heat shield materials, and the gases evolved, are described.

Project HEAT: Temperature as an Organizing Theme for Inquiry-Based Learning in the Environmental Sciences

NASA Astrophysics Data System (ADS)

Albright, T. P.; Howard, K. L.; Ewing-Taylor, J.

2014-12-01

Professionals in science, technology, engineering, and mathematics (STEM) fields do not reflect the diversity of the US population. Among the most effective ways to attract and retain underrepresented students in STEM disciplines is to provide opportunities for participation in the scientific process and interaction with practicing scientists. Project HEAT (Hot Environments, Animals, & Temperature) is "boot-camp"-style workshop aimed at increasing interest in STEM topics among underrepresented, first-generation, college-bound middle school students. Linking to our NASA-funded research project "Desert Birds in a Warming World", we focused on how surprisingly variable temperature is in space and time, why temperature is important to plants, animals, and people, and how we measure temperature in the field and from space. Perhaps more importantly, this theme was a vehicle for students to experience science as a process: field observations, brainstorming questions and hypotheses, designing experiments to test them, and analyzing and reporting their data. The centerpiece was a set of experiments with small temperature sensors and radiation shields that teams of students designed, executed at a local park, analyzed, and reported. Two years of pre and post assessments revealed that Project HEAT participants increased understanding in content areas and showed slight increases in STEM interest. Year two results were markedly stronger than year one in both assessments as well as our perception. We attribute this to earlier summer timing of the workshop, a change from two half-day weeks to one full-day week, and a more age-homogeneous selection of students. In comments, participants expressed their special enjoyment of the hands-on nature of the program and the outdoor learning. Though providing such opportunities can be challenging, our experience here suggests that it can be worth while. Project HEAT also benefited our cadre of graduate student mentors by providing exposure to K-12 learning. Although successful on the whole, the limited improvement in STEM interest suggests a fundamental challenge of making an impact during a short period of time.

Beyond the bipolar seesaw: Toward a process understanding of interhemispheric coupling

NASA Astrophysics Data System (ADS)

Pedro, Joel B.; Jochum, Markus; Buizert, Christo; He, Feng; Barker, Stephen; Rasmussen, Sune O.

2018-07-01

The thermal bipolar ocean seesaw hypothesis was advanced by Stocker and Johnsen (2003) as the 'simplest possible thermodynamic model' to explain the time relationship between Dansgaard-Oeschger (DO) and Antarctic Isotope Maxima (AIM) events. In this review we combine palaeoclimate observations, theory and general circulation model experiments to advance from the conceptual model toward a process understanding of interhemispheric coupling and the forcing of AIM events. We present four main results: (1) Changes in Atlantic heat transport invoked by the thermal seesaw are partially compensated by opposing changes in heat transport by the global atmosphere and Pacific Ocean. This compensation is an integral part of interhemispheric coupling, with a major influence on the global pattern of climate anomalies. (2) We support the role of a heat reservoir in interhemispheric coupling but argue that its location is the global interior ocean to the north of the Antarctic Circumpolar Current (ACC), not the commonly assumed Southern Ocean. (3) Energy budget analysis indicates that the process driving Antarctic warming during AIM events is an increase in poleward atmospheric heat and moisture transport following sea ice retreat and surface warming over the Southern Ocean. (4) The Antarctic sea ice retreat is itself driven by eddy-heat fluxes across the ACC, amplified by sea-ice-albedo feedbacks. The lag of Antarctic warming after AMOC collapse reflects the time required for heat to accumulate in the ocean interior north of the ACC (predominantly the upper 1500 m), before it can be mixed across this dynamic barrier by eddies.

Influence of biofilm formation on corrosion and scaling in geothermal plants

NASA Astrophysics Data System (ADS)

Kleyböcker, Anne; Lerm, Stephanie; Monika, Kasina; Tobias, Lienen; Florian, Eichinger; Andrea, Seibt; Markus, Wolfgramm; Hilke, Würdemann

2017-04-01

Process failures may occur due to corrosion and scaling processes in open loop geothermal systems. Especially after heat extraction, sulfate reducing bacteria (SRB) contribute to corrosion processes due to a more favorable temperature for their growth. In biofilms containing FeS scales, corrosion processes are enhanced. Furthermore, scales can lead to reduced pipe profiles, to a diminished heat transfer and a decrease in the wellbore injectivity. Inhibitors are frequently applied to minimize scaling in technical systems. A prerequisite for the application of inhibitors in geothermal plants located in the Molasse basin is their degradability under reservoir conditions, e. g. in a reduced environment. In order to determine the effects of scale-inhibitors on the subsurface and microbial processes, laboratory experiments were performed focusing on the microbial inhibitor degradation. First results indicate that the inhibitor degradation under anaerobic conditions is possible. Besides the inhibitor application also other techniques are investigated to economically reduce corrosion and scaling in geothermal plants. In a mobile bypass system, the influence of biofilm formation on corrosion and scaling was investigated. The bypass system was tested at a geothermal heat store in the North German Basin. The plant is operated with highly saline fluid (salinity 130 g/L) and known to be affected by SRB. The SRB contributed to corrosion damages especially at the pump in the well on the cold side. Heat shocks were successfully used in the bypass system to reduce biofilm formation as well as corrosion and scaling processes.

Coupled electro-thermal field in a high current electrolysis cell or liquid metal batteries

PubMed Central

Cai, Liwei; Ni, Haiou; Lu, Gui-Min; Yu, Jian-Guo

2018-01-01

Coupled electro-thermal field exists widely in chemical batteries and electrolysis industry. In this study, a three-dimensional numerical model, which is based on the finite-element software ANSYS, has been built to simulate the electro-thermal field in a magnesium electrolysis cell. The adjustment of the relative position of the anode and cathode can change the energy consumption of the magnesium electrolysis process significantly. Besides, the current intensity has a nonlinear effect on heat balance, and the effects of heat transfer coefficients, electrolysis and air temperature on the heat balance have been released to maintain the thermal stability in a magnesium electrolysis cell. The relationship between structure as well as process parameters and electro-thermal field has been obtained and the simulation results can provide experience for the scale-up design in liquid metal batteries. PMID:29515848

A Reconstruction Method for the Estimation of Temperatures of Multiple Sources Applied for Nanoparticle-Mediated Hyperthermia.

PubMed

Steinberg, Idan; Tamir, Gil; Gannot, Israel

2018-03-16

Solid malignant tumors are one of the leading causes of death worldwide. Many times complete removal is not possible and alternative methods such as focused hyperthermia are used. Precise control of the hyperthermia process is imperative for the successful application of such treatment. To that end, this research presents a fast method that enables the estimation of deep tissue heat distribution by capturing and processing the transient temperature at the boundary based on a bio-heat transfer model. The theoretical model is rigorously developed and thoroughly validated by a series of experiments. A 10-fold improvement is demonstrated in resolution and visibility on tissue mimicking phantoms. The inverse problem is demonstrated as well with a successful application of the model for imaging deep-tissue embedded heat sources. Thereby, allowing the physician then ability to dynamically evaluate the hyperthermia treatment efficiency in real time.

Simulation of extreme rainfall event of November 2009 over Jeddah, Saudi Arabia: the explicit role of topography and surface heating

NASA Astrophysics Data System (ADS)

Almazroui, Mansour; Raju, P. V. S.; Yusef, A.; Hussein, M. A. A.; Omar, M.

2018-04-01

In this paper, a nonhydrostatic Weather Research and Forecasting (WRF) model has been used to simulate the extreme precipitation event of 25 November 2009, over Jeddah, Saudi Arabia. The model is integrated in three nested (27, 9, and 3 km) domains with the initial and boundary forcing derived from the NCEP reanalysis datasets. As a control experiment, the model integrated for 48 h initiated at 0000 UTC on 24 November 2009. The simulated rainfall in the control experiment depicts in well agreement with Tropical Rainfall Measurement Mission rainfall estimates in terms of intensity as well as spatio-temporal distribution. Results indicate that a strong low-level (850 hPa) wind over Jeddah and surrounding regions enhanced the moisture and temperature gradient and created a conditionally unstable atmosphere that favored the development of the mesoscale system. The influences of topography and heat exchange process in the atmosphere were investigated on the development of extreme precipitation event; two sensitivity experiments are carried out: one without topography and another without exchange of surface heating to the atmosphere. The results depict that both surface heating and topography played crucial role in determining the spatial distribution and intensity of the extreme rainfall over Jeddah. The topography favored enhanced uplift motion that further strengthened the low-level jet and hence the rainfall over Jeddah and adjacent areas. On the other hand, the absence of surface heating considerably reduced the simulated rainfall by 30% as compared to the observations.

Planetary heat flow measurements.

PubMed

Hagermann, Axel

2005-12-15

The year 2005 marks the 35th anniversary of the Apollo 13 mission, probably the most successful failure in the history of manned spaceflight. Naturally, Apollo 13's scientific payload is far less known than the spectacular accident and subsequent rescue of its crew. Among other instruments, it carried the first instrument designed to measure the flux of heat on a planetary body other than Earth. The year 2005 also should have marked the launch of the Japanese LUNAR-A mission, and ESA's Rosetta mission is slowly approaching comet Churyumov-Gerasimenko. Both missions carry penetrators to study the heat flow from their target bodies. What is so interesting about planetary heat flow? What can we learn from it and how do we measure it?Not only the Sun, but all planets in the Solar System are essentially heat engines. Various heat sources or heat reservoirs drive intrinsic and surface processes, causing 'dead balls of rock, ice or gas' to evolve dynamically over time, driving convection that powers tectonic processes and spawns magnetic fields. The heat flow constrains models of the thermal evolution of a planet and also its composition because it provides an upper limit for the bulk abundance of radioactive elements. On Earth, the global variation of heat flow also reflects the tectonic activity: heat flow increases towards the young ocean ridges, whereas it is rather low on the old continental shields. It is not surprising that surface heat flow measurements, or even estimates, where performed, contributed greatly to our understanding of what happens inside the planets. In this article, I will review the results and the methods used in past heat flow measurements and speculate on the targets and design of future experiments.

Vapor Hydrogen Peroxide as Alternative to Dry Heat Microbial Reduction

NASA Technical Reports Server (NTRS)

Cash, Howard A.; Kern, Roger G.; Chung, Shirley Y.; Koukol, Robert C.; Barengoltz, Jack B.

2006-01-01

The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with appropriate specification, in NPG8020.12C as a low temperature complementary technique to the dry heat sterilization process. A series of experiments were conducted in vacuum to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. With this knowledge of D values, sensible margins can be applied in a planetary protection specification. The outcome of this study provided an optimization of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D value may be imposed, a process humidity range for which the worst case D value may be imposed, and robustness to selected spacecraft material substrates.

Temperature field simulation on Ti6Al4V and Inconel718 heated by continuous infrared laser

NASA Astrophysics Data System (ADS)

Wang, Yanshen; Zhang, Zheng; Feng, Weiwei; Wang, Bo; Gai, Yuxian

2014-08-01

Laser assisted machining technology can heat and soften metals, which can be used for improving the machinability of superalloys such as Ti6Al4V and Inconel718. Researches on temperature field simulation of Ti6Al4V and Inconel718 are conducted in this paper. A thermal differential equation is established based on Fourier's law and energy conservation law. Then, a model using ABAQUS for simulating heat transfer process is brought out, which is then experimentally validated. Using the simulation model, detailed investigations on temperature field simulation are carried out in Ti6Al4V and Inconel718. According to simulation, surface temperature of the two superalloys eventually reaches their peak values, and the peak temperature of Ti6Al4V is much higher than that of Inconel718. To further investigate temperature heated by laser, laser parameters such as power, scanning velocity, laser spot radius and inclination angle are set to be variables separately for simulation. Simulation results show that laser power and laser spot radius are predominant factors in heating process compared with the influence of scanning velocity and inclination angle. Simulations in this paper provide valuable references for parameter optimization in the following laser heating experiments, which plays an important role in laser assisted machining.

Development of processes for the production of solar grade silicon from halides and alkali metals

NASA Technical Reports Server (NTRS)

Dickson, C. R.; Gould, R. K.

1980-01-01

High temperature reactions of silicon halides with alkali metals for the production of solar grade silicon in volume at low cost were studied. Experiments were performed to evaluate product separation and collection processes, measure heat release parameters for scaling purposes, determine the effects of reactants and/or products on materials of reactor construction, and make preliminary engineering and economic analyses of a scaled-up process.

Laboratory Experiments Lead to a New Understanding of Wildland Fire Spread

NASA Astrophysics Data System (ADS)

Cohen, J. D.; Finney, M.; McAllister, S.

2015-12-01

Wildfire flame spread results from a sequence of ignitions where adjacent fuel particles heat from radiation and convection leading to their ignition. Surprisingly, after decades of fire behavior research an experimentally based, fundamental understanding of wildland fire spread processes has not been established. Modelers have commonly assumed radiation to be the dominant heating mechanism; that is, radiation heat transfer primarily determines wildland fire spread. We tested this assumption by focusing on how fuel ignition occurs with a renewed emphasis on experimental research. Our experiments show that fuel particle size can non-linearly influence a fuel particle's convective heat transfer. Fine fuels (less than 1 mm) can convectively cool in ambient air such that radiation heating is insufficient for ignition and thus fire spread. Given fire spread with insufficient radiant heating, fuel particle ignition must occur convectively from flame contact. Further experimentation reveals that convective heating and particle ignition occur when buoyancy-induced instabilities and vorticity force flames down and forward to produce intermittent contact with the adjacent fuel bed. Experimental results suggest these intermittent forward flame extensions are buoyancy driven with predictable average frequencies for flame zones ranging from laboratory (10-2 m) to field scales (101m). Measured fuel particle temperatures and boundary conditions during spreading laboratory fires reveal that convection heat transfer from intermittent flame contact is the principal mechanism responsible for heating fine fuel particles to ignition. Our experimental results describe how fine fuel particles convectively heat to ignition from flame contact related to the buoyant dynamics of spreading flame fronts. This research has caused a rethinking of some of the most basic concepts in wildland fuel particle ignition and flame spread.

Demonstration of Efficient Core Heating of Magnetized Fast Ignition in FIREX project

NASA Astrophysics Data System (ADS)

Johzaki, Tomoyuki

2017-10-01

Extensive theoretical and experimental research in the FIREX ``I project over the past decade revealed that the large angular divergence of the laser generated electron beam is one of the most critical problems inhibiting efficient core heating in electron-driven fast ignition. To solve this problem, beam guiding using externally applied kilo-tesla class magnetic field was proposed, and its feasibility has recently been numerically demonstrated. In 2016, integrated experiments at ILE Osaka University demonstrated core heating efficiencies reaching > 5 % and heated core temperatures of 1.7 keV. In these experiments, a kilo-tesla class magnetic field was applied to a cone-attached Cu(II) oleate spherical solid target by using a laser-driven capacitor-coil. The target was then imploded by G-XII laser and heated by the PW-class LFEX laser. The heating efficiency was evaluated by measuring the number of Cu-K- α photons emitted. The heated core temperature was estimated by the X-ray intensity ratio of Cu Li-like and He-like emission lines. To understand the detailed dynamics of the core heating process, we carried out integrated simulations using the FI3 code system. Effects of magnetic fields on the implosion and electron beam transport, detailed core heating dynamics, and the resultant heating efficiency and core temperature will be presented. I will also discuss the prospect for an ignition-scale design of magnetized fast ignition using a solid ball target. This work is partially supported by JSPA KAKENHI Grant Number JP16H02245, JP26400532, JP15K21767, JP26400532, JP16K05638 and is performed with the support and the auspices of the NIFS Collaboration Research program (NIFS12KUGK057, NIFS15KUGK087).

Meta-Stable Magnetic Domain States That Prevent Reliable Absolute Palaeointensity Experiments Revealed By Magnetic Force Microscopy

NASA Astrophysics Data System (ADS)

de Groot, L. V.; Fabian, K.; Bakelaar, I. A.; Dekkers, M. J.

2014-12-01

Obtaining reliable estimates of the absolute palaeointensity of the Earth's magnetic field is notoriously difficult. Many methods to obtain paleointensities from suitable records such as lavas and archeological artifacts involve heating the samples. These heating steps are believed to induce 'magnetic alteration' - a process that is still poorly understood but prevents obtaining correct paleointensity estimates. To observe this magnetic alteration directly we imaged the magnetic domain state of titanomagnetite particles - a common carrier of the magnetic remanence in samples used for paleointensity studies. We selected samples from the 1971-flow of Mt. Etna from a site that systematically yields underestimates of the known intensity of the paleofield - in spite of rigorous testing by various groups. Magnetic Force Microscope images were taken before and after a heating step typically used in absolute palaeointensity experiments. Before heating, the samples feature distinct, blocky domains that sometimes seem to resemble a classical magnetite domain structure. After imparting a partial thermo-remanent magnetization at a temperature often critical to paleointensity experiments (250 °C) the domain state of the same titanomagnetite grains changes into curvier, wavy domains. Furthermore, these structures appeared to be unstable over time: after one-year storage in a magnetic field-free environment the domain states evolved into a viscous remanent magnetization state. Our observations may qualitatively explain reported underestimates from technically successful paleointensity experiments for this site and other sites reported previously. Furthermore the occurrence of intriguing observations such as 'the drawer storage effect' by Shaar et al (EPSL, 2011), and viscous magnetizations observed by Muxworthy and Williams (JGR, 2006) may be (partially) explained by our observations. The major implications of our study for all palaeointensity methods involving heating may be evident.

STS-87 Day 07 Highlights

NASA Technical Reports Server (NTRS)

1997-01-01

On this seventh day of the STS-87 mission, the flight crew, Cmdr. Kevin R. Kregel, Pilot Steven W. Lindsey, Mission Specialists Winston E. Scott, Kalpana Chawla, and Takao Doi, and Payload Specialist Leonid K. Kadenyuk turn their attention to a variety of experiments inside the Shuttle's cabin. These experiments include the processing of several samples of materials in the glovebox facility in Columbia's middeck; the experiment called PEP, which involves heating samples and then recording the mixture as it resolidifies; and the study of plant growth in space.

Comparison of Tobacco Host Cell Protein Removal Methods by Blanching Intact Plants or by Heat Treatment of Extracts.

PubMed

Buyel, Johannes F; Hubbuch, Jürgen; Fischer, Rainer

2016-08-08

Plants not only provide food, feed and raw materials for humans, but have also been developed as an economical production system for biopharmaceutical proteins, such as antibodies, vaccine candidates and enzymes. These must be purified from the plant biomass but chromatography steps are hindered by the high concentrations of host cell proteins (HCPs) in plant extracts. However, most HCPs irreversibly aggregate at temperatures above 60 °C facilitating subsequent purification of the target protein. Here, three methods are presented to achieve the heat precipitation of tobacco HCPs in either intact leaves or extracts. The blanching of intact leaves can easily be incorporated into existing processes but may have a negative impact on subsequent filtration steps. The opposite is true for heat precipitation of leaf extracts in a stirred vessel, which can improve the performance of downstream operations albeit with major changes in process equipment design, such as homogenizer geometry. Finally, a heat exchanger setup is well characterized in terms of heat transfer conditions and easy to scale, but cleaning can be difficult and there may be a negative impact on filter capacity. The design-of-experiments approach can be used to identify the most relevant process parameters affecting HCP removal and product recovery. This facilitates the application of each method in other expression platforms and the identification of the most suitable method for a given purification strategy.

Heat Transfer of Thermocapillary Convection in a Two-Layered Fluid System Under the Influence of Magnetic Field

NASA Technical Reports Server (NTRS)

Ramachandran, N.; Ludovisis, D.; Cha, S. S.

2006-01-01

Heat transfer of a two-layer fluid system has been of great importance in a variety of industrial applications. For example, the phenomena of immiscible fluids can be found in materials processing and heat exchangers. Typically in solidification from a melt, the convective motion is the dominant factor that affects the uniformity of material properties. In the layered flow, thermocapillary forces can come into an important play, which was first emphasized by a previous investigator in 1958. Under extraterrestrial environments without gravity, thermocapillary effects can be a more dominant factor, which alters material properties in processing. Control and optimization of heat transfer in an immiscible fluid system need complete understanding of the flow phenomena that can be induced by surface tension at a fluid interface. The present work is focused on understanding of the magnetic field effects on thermocapillary convection, in order to optimize material processing. That is, it involves the study of the complicated phenomena to alter the flow motion in crystal growth. In this effort, the Marangoni convection in a cavity with differentially heated sidewalls is investigated with and without the influence of a magnetic field. As a first step, numerical analyses are performed, by thoroughly investigating influences of all pertinent physical parameters. Experiments are then conducted, with preliminary results, for comparison with the numerical analyses.

Processing of Bulk YBa2Cu3O(7-x) High Temperature Superconductor Materials for Gravity Modification Experiments and Performance Under AC Levitation

NASA Technical Reports Server (NTRS)

Koczor, Ronald; Noever, David; Hiser, Robert

1999-01-01

We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of bulk-processed high temperature superconductor disks. Others have indicated that large annular disks (on the order of 25cm diameter) and AC levitation fields play an essential role in their observed experiments. We report experiments in processing such large bulk superconductors. Successful results depend on material mechanical characteristics, and pressure and heat treat protocols. Annular disks having rough dimensions of 30cm O.D., 7cm I.D. and 1 cm thickness have been routinely fabricated and tested under AC levitation fields ranging from 45 to 300OHz. Implications for space transportation initiatives and power storage flywheel technology will be discussed.

A probabilistic model of a porous heat exchanger

NASA Technical Reports Server (NTRS)

Agrawal, O. P.; Lin, X. A.

1995-01-01

This paper presents a probabilistic one-dimensional finite element model for heat transfer processes in porous heat exchangers. The Galerkin approach is used to develop the finite element matrices. Some of the submatrices are asymmetric due to the presence of the flow term. The Neumann expansion is used to write the temperature distribution as a series of random variables, and the expectation operator is applied to obtain the mean and deviation statistics. To demonstrate the feasibility of the formulation, a one-dimensional model of heat transfer phenomenon in superfluid flow through a porous media is considered. Results of this formulation agree well with the Monte-Carlo simulations and the analytical solutions. Although the numerical experiments are confined to parametric random variables, a formulation is presented to account for the random spatial variations.

The Effects of Gravity on the Crystallization Behavior of Heavy Metal Fluoride Glasses

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.; Smith, Guy A.

2004-01-01

Heavy metal fluoride glasses are used in such applications as fiber lasers and laser amplifiers. ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) is one of the more commonly used heavy metal fluoride glasses. ZBLAN is an infrared transmitter and has a theoretical attenuation coefficient of 0.002 db/km. However, due to impurities and small crystallites this attenuation coefficient has not been achieved to date. ZBLAN is a fragile glass which can lead to rapid crystallization, if the glass is not cooled rapidly to below the glass transition temperature or if the glass is reheated near the crystallization temperature for any period of time. Studies carried on at Marshall Space Flight Center and the University of Alabama in Huntsville since 1993 have shown that heating ZBLAN glass at the crystallization temperature in reduced gravity results in a suppression of crystallization when compared to ZBLAN processed in unit gravity. These studies utilized NASA's KC-135 aircraft and the Conquest sounding rocket. In the first series of experiments, short lengths of ZBLAN fiber were heated to the crystallization temperature in reduced gravity on board the KC- 135 and the Conquest sounding rocket and compared with fibers heated in unit gravity. The fibers processed in reduced gravity showed no evidence of crystallization when studied with x-ray diffraction and scanning electron microscopy. However, the fibers processed in unit gravity were completely crystallized. Subsequent experiments included heating small pieces of ZBLAN glass at the crystallization temperature while viewing with a video camera to follow the crystallization phenomenon. In this experiment crystallization was observed in reduced gravity, however, it was suppressed when compared to heating in unit gravity. In the most recent experiment on board the KC-135, rapid thermal analysis of ZBLAN was performed. A mechanism to explain the observations has been proposed. This mechanism is based on shear thinning whereby, the glass undergoes a reduction in viscosity in the 10(exp 5) - 10(exp 7) poise range, allowing more rapid diffusion and thus crystallization. It is proposed that this mechanism is suppressed in reduced gravity. An experiment is presently being conducted to test this theory. With increased knowledge of ZBLAN behavior in reduced gravity, three low earth orbit tiber drawing facilities have been designed. One would be suitable for use on the International Space Station, another while aboard the Space Shuttle and the third system is a fully automated facility which would operate independently of the ISS or Shuttle in a free float mode. The primary benefits of free floating a facility in LEO includes a higher quality of microgravity and reduced safety concerns since it is not in a manned environment.

Experimental metrology to obtain thermal phonon transmission coefficients at solid interfaces

NASA Astrophysics Data System (ADS)

Hua, Chengyun; Chen, Xiangwen; Ravichandran, Navaneetha K.; Minnich, Austin J.

2017-05-01

Interfaces play an essential role in phonon-mediated heat conduction in solids, impacting applications ranging from thermoelectric waste heat recovery to heat dissipation in electronics. From the microscopic perspective, interfacial phonon transport is described by transmission coefficients that link vibrational modes in the materials composing the interface. However, direct experimental determination of these coefficients is challenging because most experiments provide a mode-averaged interface conductance that obscures the microscopic detail. Here, we report a metrology to extract thermal phonon transmission coefficients at solid interfaces using ab initio phonon transport modeling and a thermal characterization technique, time-domain thermoreflectance. In combination with transmission electron microscopy characterization of the interface, our approach allows us to link the atomic structure of an interface to the spectral content of the heat crossing it. Our work provides a useful perspective on the microscopic processes governing interfacial heat conduction.

Thermal design, rating and second law analysis of shell and tube condensers based on Taguchi optimization for waste heat recovery based thermal desalination plants

NASA Astrophysics Data System (ADS)

Chandrakanth, Balaji; Venkatesan, G; Prakash Kumar, L. S. S; Jalihal, Purnima; Iniyan, S

2018-03-01

The present work discusses the design and selection of a shell and tube condenser used in Low Temperature Thermal Desalination (LTTD). To optimize the key geometrical and process parameters of the condenser with multiple parameters and levels, a design of an experiment approach using Taguchi method was chosen. An orthogonal array (OA) of 25 designs was selected for this study. The condenser was designed, analysed using HTRI software and the heat transfer area with respective tube side pressure drop were computed using the same, as these two objective functions determine the capital and running cost of the condenser. There was a complex trade off between the heat transfer area and pressure drop in the analysis, however second law analysis was worked out for determining the optimal heat transfer area vs pressure drop for condensing the required heat load.

Effect of hyperthermia on the repair of sublethal radiation damage in normal and membrane fatty acid substituted fibroblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolters, H.; Kelholt, D.; Konings, A.W.

1987-02-01

The interaction of heat and X irradiation was studied in normal and polyunsaturated fatty acid (PUFA) substituted mouse fibroblast LM cells. As a result of the substitution the membranes of the PUFA cells were more fluid than the membranes of the normal cells. Three different heat doses were applied (60 min 42 degrees C, 20 min 43 degrees C, and 10 min 44 degrees C) in combination with single or split doses of X rays. Heat radiosensitization was the largest for the 60 min 42 degrees C treatment. Heat radiosensitization and the heat-induced inhibition of the rate of sublethal damagemore » repair were the same for the normal and the PUFA cells. It is concluded from the experiments reported that the processes of hyperthermic inhibition of SLD repair and hyperthermic radiosensitization are independent of membrane fluidity and membrane fatty acid composition.« less

Experimental metrology to obtain thermal phonon transmission coefficients at solid interfaces

DOE PAGES

Hua, Chengyun; Chen, Xiangwen; Ravichandran, Navaneetha K.; ...

2017-05-17

Interfaces play an essential role in phonon-mediated heat conduction in solids, impacting applications ranging from thermoelectric waste heat recovery to heat dissipation in electronics. From the microscopic perspective, interfacial phonon transport is described by transmission coefficients that link vibrational modes in the materials composing the interface. But, direct experimental determination of these coefficients is challenging because most experiments provide a mode-averaged interface conductance that obscures the microscopic detail. Here, we report a metrology to extract thermal phonon transmission coefficients at solid interfaces using ab initio phonon transport modeling and a thermal characterization technique, time-domain thermoreflectance. In combination with transmission electronmore » microscopy characterization of the interface, our approach allows us to link the atomic structure of an interface to the spectral content of the heat crossing it. This work provides a useful perspective on the microscopic processes governing interfacial heat conduction.« less

Experimental research on the application of HTAC in small-size heating furnace

NASA Astrophysics Data System (ADS)

Zhou, Yu; Qin, Chaokui; Yang, Jun; Chen, Zhiguang

2018-03-01

High temperature air combustion (HTAC) technology, which is also known as regenerative combustion technology, has realized energy saving, CO2 and NOx emissions reduction and low-noise combustion. It has been widely applied in various types of heating furnace and has achieved good energy-saving effect. However, there is little application of this technology in small-size furnace. In this paper, a small-size regenerative heating furnace was built in the laboratory and experiments were carried out on it. The result shows that, if the transport frequency was set to a group per min, the center temperature of processed workpiece at the rated conditions (i.e. burner power is 300 kW and switching time is 60s) reached 1133°C. And the efficiency of the heating furnace was 36.8%. Then the derived comprehensive heat transfer coefficient was 168 W/(m2˙°C).

Process optimization of joining by upset bulging with local heating

NASA Astrophysics Data System (ADS)

Rusch, Michael; Almohallami, Amer; Sviridov, Alexander; Bonk, Christian; Behrens, Bernd-Arno; Bambach, Markus

2017-10-01

Joining by upset bulging is a mechanical joining method where axial load is applied to a tube to form two revolving bulges, which clamp the parts to be joined and create a force and form fit. It can be used to join tubes with other structures such as sheets, plates, tubes or profiles of the same or different materials. Other processes such as welding are often limited in joining multi-material assemblies or high-strength materials. With joining by upset bulging at room temperature, the main drawback is the possible initiation of damage (cracks) in the inner buckling zone because of high local stresses and strains. In this paper, a method to avoid the formation of cracks is introduced. Before forming the bulge the tube is locally heated by an induction coil. For the construction steel (E235+N) a maximum temperature of 700 °C was used to avoid phase transformation. For the numerical study of the process the mechanical properties of the tube material were examined at different temperatures and strain rates to determine its flow curves. A parametrical FE model was developed to simulate the bulging process with local heating. Experiments with local heating were executed and metallographic studies of the bulging area were conducted. While specimens heated to 500 °C showed small cracks left, damage-free flanges could be created at 600 and 700 °C. Static testing of damage-free bulges showed improvements in tensile strength and torsion strength compared to bulges formed at room-temperature, while bending and compression behavior remained nearly unchanged. In cyclic testing the locally heated specimens underwent about 3.7 times as many cycles before failure as the specimens formed at room temperature.

Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

NASA Astrophysics Data System (ADS)

Andrzejczyk, Rafał; Muszyński, Tomasz

2016-12-01

The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

DOE PAGES

Myra, J. R.; Russell, D. A.; D’Ippolito, D. A.; ...

2011-01-01

Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from themore » simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.« less

Figuring process of potassium dihydrogen phosphate crystal using ion beam figuring technology.

PubMed

Li, Furen; Xie, Xuhui; Tie, Guipeng; Hu, Hao; Zhou, Lin

2017-09-01

Currently, ion beam figuring (IBF) technology has presented many excellent performances in figuring potassium dihydrogen phosphate (KDP) crystals, such as it is a noncontact figuring process and it does not require polishing fluid. So, it is a very clean figuring process and does not introduce any impurities. However, the ion beam energy deposited on KDP crystal will heat the KDP crystal and may generate cracks on it. So, it is difficult directly using IBF technology to figure KDP crystal, as oblique incident IBF (OI-IBF) has lower heat deposition, higher removal rate, and smoother surface roughness compared to normal incident IBF. This paper studied the process of using OI-IBF to figure KDP crystal. Removal rates and removal functions at different incident angles were first investigated. Then heat depositions on a test work piece were obtained through experiments. To validate the figuring process, a KDP crystal with a size of 200  mm×200  mm×12  mm was figured by OI-IBF. After three iterations using the OI-IBF process, the surface error decreases from the initial values with PV 1.986λ RMS 0.438λ to PV 0.215λ RMS 0.035λ. Experimental results indicate that OI-IBF is feasible and effective to figure KDP crystals.

Cutaway line drawing of STS-34 middeck experiment Polymer Morphology (PM)

NASA Technical Reports Server (NTRS)

1989-01-01

Cutaway line drawing shows components of STS-34 middeck experiment Polymer Morphology (PM). Components include the EAC, heat exchanger, sample cell control (SCC), sample cells, source, interferometer, electronics, carousel drive, infrared (IR) beam, and carousel. PM, a 3M-developed organic materials processing experiment, is designed to explore the effects of microgravity on polymeric materials as they are processed in space. The samples of polymeric materials being studied in the PM experiment are thin films (25 microns or less) approximately 25mm in diameter. The samples are mounted between two infrared transparent windows in a specially designed infrared cell that provides the capability of thermally processing the samples to 200 degrees Celsius with a high degree of thermal control. The samples are mounted on a carousel that allows them to be positioned, one at a time, in the infrared beam where spectra may be acquired. The Generic Electronics Module (GEM) provides all carousel and

Experiments on aerosol-induced cooling in the nocturnal boundary layer

NASA Astrophysics Data System (ADS)

Sreenivas, K.; Singh, D. K.; Vk, P.; Mukund, V.; Subramanian, G.

2012-12-01

In the nocturnal boundary layer (NBL), under calm & clear-sky conditions, radiation is the principal mode of heat transfer & it determines the temperature distribution close to the ground. Radiative processes thus influence the surface energy budget, & play a decisive role in many micro-meteorological processes including the formation of radiation-fog & inversion layer. Here, we report hyper-cooling of air layers close to the ground that has a radiative origin. Resulting vertical temperature distribution has an anomalous profile with an elevated minimum few decimetres above the ground (known as Lifted Temperature Minimum; LTM). Even though the first observation of this type of profile dates back to 1930s, its origin has not been explained till recently. We report field experiments to elucidate effects of emissivity and other physical properties of the ground on the LTM profile. Field observations clearly indicate that LTM-profiles are observed as a rule in the lowest meter of the NBL. We also demonstrate that the air-layer near the ground, rather than the ground itself, leads the post sunset cooling. This fact changes the very nature of the sensible heat-flux boundary condition. A laboratory experimental setup has been developed that can reproduce LTM. Lab-experiments demonstrate that the high cooling rates observed in the field experiments arise from the presence of aerosols & the intensity of cooling is proportional to aerosol concentration (Fig-1). We have also captured penetrative convection cells in the field experiments (Fig-2). Results presented here thus help in parameterizing transport processes in the NBL.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, Amy B.; Stauffer, Philip H.; Reed, Donald T.

The primary objective of the experimental effort described here is to aid in understanding the complex nature of liquid, vapor, and solid transport occurring around heated nuclear waste in bedded salt. In order to gain confidence in the predictive capability of numerical models, experimental validation must be performed to ensure that (a) hydrological and physiochemical parameters and (b) processes are correctly simulated. The experiments proposed here are designed to study aspects of the system that have not been satisfactorily quantified in prior work. In addition to exploring the complex coupled physical processes in support of numerical model validation, lessons learnedmore » from these experiments will facilitate preparations for larger-scale experiments that may utilize similar instrumentation techniques.« less

Materials International Space Station Experiment (MISSE) Arrival

NASA Image and Video Library

2017-10-02

The Materials International Space Station Experiment-Flight Facility, or MISSE-FF, hardware arrived at the Space Station Processing Facility low bay at NASA's Kennedy Space Center in Florida. MISSE will be unpacked for integration and processing. MISSE will be used to test various materials and computing elements on the exterior of the space station. They will be exposed to the harsh environment of low-Earth orbit, including to a vacuum, atomic oxygen, ultraviolet radiation, direct sunlight and extreme heat and cold. The experiment will provide a better understanding of material durability, from coatings to electronic sensors, which could be applied to future spacecraft designs. MISSE will be delivered to the space station on a future commercial resupply mission.

Crystallization of Calcium Carbonate in a Large Scale Field Study

NASA Astrophysics Data System (ADS)

Ueckert, Martina; Wismeth, Carina; Baumann, Thomas

2017-04-01

The long term efficiency of geothermal facilities and aquifer thermal energy storage in the carbonaceous Malm aquifer in the Bavarian Molasse Basin is seriously affected by precipitations of carbonates. This is mainly caused by pressure and temperature changes leading to oversaturation during production. Crystallization starts with polymorphic nuclei of calcium carbonate and is often described as diffusion-reaction controlled. Here, calcite crystallization is favoured by high concentration gradients while aragonite crystallization is occurring at high reaction rates. The factors affecting the crystallization processes have been described for simplified, well controlled laboratory experiments, the knowledge about the behaviour in more complex natural systems is still limited. The crystallization process of the polymorphic forms of calcium carbonate were investigated during a heat storage test at our test site in the eastern part of the Bavarian Molasse Basin. Complementary laboratory experiments in an autoclave were run. Both, field and laboratory experiments were conducted with carbonaceous tap water. Within the laboratory experiments additionally ultra pure water was used. To avoid precipitations of the tap water, a calculated amount of {CO_2} was added prior to heating the water from 45 - 110°C (laboratory) resp. 65 - 110°C (field). A total water volume of 0.5 L (laboratory) resp. 1 L (field) was immediately sampled and filtrated through 10 - 0.1

Some aspects of the problem of secondary eyewall formation in idealized three-dimensional nonlinear simulations

NASA Astrophysics Data System (ADS)

Menelaou, K.; Yau, M. K.; Martinez, Y.

2014-09-01

Some aspects of the problem of secondary eyewall formation (SEF) are investigated with the aid of an idealized model. A series of experiments are conducted, starting with a strong annular vortex embedded in a quiescent background flow and forced by the sustained heating associated with a spiral rainband (control experiment). Following this, two experiments are configured to assess the impact of vertical wind shear (VWS) in the SEF process. The importance of the boundary layer force imbalance is finally investigated in a number of simulations in which surface and boundary layer physics are included. From the control experiment, it is found that in the absence of background environmental flow, the sustained latent heating associated with a spiral rainband can form a secondary eyewall even in the absence of a frictional boundary layer. The presence of VWS acts negatively in the SEF process by disrupting the organization of the potential vorticity induced by the rainband. When boundary layer physics is included, some similarities with previous studies are seen, but there is no SEF. These results suggest that the boundary layer most likely contributes to, rather than initiate, a secondary eyewall. This article was corrected on 10 OCT 2014. See the end of the full text for details.

LABORATORY MICROCOSM EXPERIMENTS OF OXIDATION PROCESSES AFTER STEAM INJECTION

EPA Science Inventory

Aggressive thermal methods such as steam injection or resistive heating are known to be effective for the recovery of many types of volatile and semivolatile compounds. It has been suggested that oxidation or other chemical reactions that occur at remediation temperatures can ai...

Experiments and Modeling to Support Field Test Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Peter Jacob; Bourret, Suzanne Michelle; Zyvoloski, George Anthony

Disposition of heat-generating nuclear waste (HGNW) remains a continuing technical and sociopolitical challenge. We define HGNW as the combination of both heat generating defense high level waste (DHLW) and civilian spent nuclear fuel (SNF). Numerous concepts for HGNW management have been proposed and examined internationally, including an extensive focus on geologic disposal (c.f. Brunnengräber et al., 2013). One type of proposed geologic material is salt, so chosen because of its viscoplastic deformation that causes self-repair of damage or deformation induced in the salt by waste emplacement activities (Hansen and Leigh, 2011). Salt as a repository material has been tested atmore » several sites around the world, notably the Morsleben facility in Germany (c.f. Fahland and Heusermann, 2013; Wollrath et al., 2014; Fahland et al., 2015) and at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. Evaluating the technical feasibility of a HGNW repository in salt is an ongoing process involving experiments and numerical modeling of many processes at many facilities.« less

Fast gene ontology based clustering for microarray experiments.

PubMed

Ovaska, Kristian; Laakso, Marko; Hautaniemi, Sampsa

2008-11-21

Analysis of a microarray experiment often results in a list of hundreds of disease-associated genes. In order to suggest common biological processes and functions for these genes, Gene Ontology annotations with statistical testing are widely used. However, these analyses can produce a very large number of significantly altered biological processes. Thus, it is often challenging to interpret GO results and identify novel testable biological hypotheses. We present fast software for advanced gene annotation using semantic similarity for Gene Ontology terms combined with clustering and heat map visualisation. The methodology allows rapid identification of genes sharing the same Gene Ontology cluster. Our R based semantic similarity open-source package has a speed advantage of over 2000-fold compared to existing implementations. From the resulting hierarchical clustering dendrogram genes sharing a GO term can be identified, and their differences in the gene expression patterns can be seen from the heat map. These methods facilitate advanced annotation of genes resulting from data analysis.

Heavy Ion Fusion Science Virtual National Laboratory 4th Quarter 2009 Milestone Report: Measure and simulate target temperature and dynamic response in optimized NDCX-I configurations with initial diagnostics suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bieniosek, F.M.; Barnard, J.J.; Henestroza, E.

2009-09-30

This milestone has been met. The effort contains two main components: (1) Experimental results of warm dense matter target experiments on optimized NDCX-I configurations that include measurements of target temperature and transient target behavior. (2) A theoretical model of the target response to beam heating that includes an equilibrium heating model of the target foil and a model for droplet formation in the target for comparison with experimental results. The experiments on ion-beam target heating use a 300-350-keV K{sup +} pulsed beam from the Neutralized Compression Drift Experiment (NDCX-I) accelerator at LBNL. The NDCX-I accelerator delivers an uncompressed pulse beammore » of several microseconds with a typical power density of >100 kW/cm{sup 2} over a final focus spot size of about 1 mm. An induction bunching module the NDCX-I compresses a portion of the beam pulse to reach a much higher power density over 2 nanoseconds. Under these conditions the free-standing foil targets are rapidly heated to temperatures to over 4000 K. We model the target thermal dynamics using the equation of heat conduction for the temperature T(x,t) as a function of time (t) and spatial dimension along the beam direction (x). The competing cooling processes release energy from the surface of the foil due to evaporation, radiation, and thermionic (Richardson) emission. A description of the experimental configuration of the target chamber and results from initial beam-target experiments are reported in our FY08 4th Quarter and FY09 2nd Quarter Milestone Reports. The WDM target diagnostics include a high-speed multichannel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. The fast optical pyrometer is a unique and significant new diagnostic which provides valuable information on the temperature evolution of the heated target.« less

Wear behavior of carbonitride-treated ploughshares produced from 30MnB5 steel for soil tillage applications

NASA Astrophysics Data System (ADS)

Yazici, A.

2011-09-01

The effects of gaseous carbonitriding processes on wear characteristics of 30MnB5 steel were investigated. The matrix of the carbonitride treated samples has a better wear resistance compared to the substrates of the conventionally heat-treated sample in laboratory conditions. The carbonitriding treatment condition giving rise to the lowest wear weight loss with the pin-on-disc wear machine was selected in order to harden ploughshare specimens to be tested in field experiments. The carbonitriding process at 860°C, with 0.9% C, and 0.6 m3/h NH3 for 105 min and quenched in 60°C oil followed by a 60 min tempering process at 140°C decreased 14.65% of total wear weight loss and 26.47% of total wear dimension loss of the ploughshare specimens in comparison to the conventional heat treatment process in field operational conditions.

Enabling two-phase microfluidic thermal transport systems using a novel thermal-flux degassing and fluid charging approach

NASA Astrophysics Data System (ADS)

Singh Dhillon, Navdeep; Pisano, Albert P.

2014-03-01

A novel two-port thermal-flux method has been proposed and demonstrated for degassing and charging two-phase microfluidic thermal transport systems with a degassed working fluid. In microscale heat pipes and loop heat pipes (mLHPs), small device volumes and large capillary forces associated with smaller feature sizes render conventional vacuum pump-based degassing methods quite impractical. Instead, we employ a thermally generated pressure differential to purge non-condensable gases from these devices before charging them with a degassed working fluid in a two-step process. Based on the results of preliminary experiments studying the effectiveness and reliability of three different high temperature-compatible device packaging approaches, an optimized compression packaging technique was developed to degas and charge a mLHP device using the thermal-flux method. An induction heating-based noninvasive hermetic sealing approach for permanently sealing the degassed and charged mLHP devices has also been proposed. To demonstrate the efficacy of this approach, induction heating experiments were performed to noninvasively seal 1 mm square silicon fill-hole samples with donut-shaped solder preforms. The results show that the minimum hole sealing induction heating time is heat flux limited and can be estimated using a lumped capacitance thermal model. However, further continued heating of the solder uncovers the hole due to surface tension-induced contact line dynamics of the molten solder. It was found that an optimum mass of the solder preform is required to ensure a wide enough induction-heating time window for successful sealing of a fill-hole.

Features of Afterbody Radiative Heating for Earth Entry

NASA Technical Reports Server (NTRS)

Johnston, Christopher O.; Brandis, Aaron

2014-01-01

Radiative heating is identified as a major contributor to afterbody heating for Earth entry capsules at velocities above 10 km/s. Because of rate-limited electron-ion recombination processes, a large fraction of the electronically-excited N and O atoms produced in the high temperature/pressure forebody remain as they expand into the afterbody region, which results in significant afterbody radiation. Large radiative heating sensitivities to electron-impact ionization rates and escape factors are identified. Ablation products from a forebody ablator are shown to increase the afterbody radiation by as much as 40%. The tangent-slab radiation transport approach is shown to over-predict the radiative flux by as much as 40% in the afterbody, therefore making the more computationally expensive ray-tracing approach necessary for accurate radiative flux predictions. For the Stardust entry, the afterbody radiation is predicted to be nearly twice as large as the convective heating during the peak heating phase of the trajectory. Comparisons between simulations and the Stardust Echelle observation measurements, which are shown to be dominated by afterbody emission, indicate agreement within 20% for various N and O lines. Similarly, calorimeter measurements from the Fire II experiment are identified as a source of validation data for afterbody radiation. For the afterbody calorimeter measurement closest to the forebody, which experiences the largest afterbody radiative heating component, the convective heating alone is shown to under-predict the measurement, even for the fullycatalytic assumption. Agreement with the measurements is improved with the addition of afterbody radiation. These comparisons with Stardust and Fire II measurements provide validation that the significant afterbody radiation values proposed in this work are legitimate.

Gradient Heating Facility in the Materials Science Double Rack (MSDR) on Spacelab-1 Module

NASA Technical Reports Server (NTRS)

1983-01-01

The Space Shuttle was designed to carry large payloads into Earth orbit. One of the most important payloads is Spacelab. The Spacelab serves as a small but well-equipped laboratory in space to perform experiments in zero-gravity and make astronomical observations above the Earth's obscuring atmosphere. In this photograph, Payload Specialist, Ulf Merbold, is working at Gradient Heating Facility on the Materials Science Double Rack (MSDR) inside the science module in the Orbiter Columbia's payload bay during STS-9, Spacelab-1 mission. Spacelab-1, the joint ESA (European Space Agency)/NASA mission, was the first operational flight for the Spacelab, and demonstrated new instruments and methods for conducting experiments that are difficult or impossible in ground-based laboratories. This facility performed, in extremely low gravity, a wide variety of materials processing experiments in crystal growth, fluid physics, and metallurgy. The Marshall Space Flight Center had overall management responsibilities.

Surface currents in the Canary Basin from drifter observations

NASA Astrophysics Data System (ADS)

Zhou, Meng; Paduan, Jeffrey D.; Niiler, Pearn P.

2000-09-01

Satellite-tracked drifting buoys, deployed in the Canary Basin as part of the Subduction Experiment between July 1991 and October 1993 and the French Semaphore Experiment during October 1993, were used to obtain a description of surface currents and temperature in the Canary Basin. The study focuses on surface water convergence, eddy energy production, and heat transport. The Azores Current associated with the subtropical convergence zone is clearly visible at 34°N, and bifurcates around 22°W, with the major branch of the current circling the Madeira plateau and joining the Canary Current along the continental slope. Eddy kinetic energy maxima are found along the Azores Current. The mean current revealed a region of maximum convergence north of the Azores Current around longitude 29°W occurring with a negative heating anomaly and positive work done by the Reynolds stress. The southward meridional temperature fluxes in the Ekman layer (0-50 m) between 37°W and the African and European coast are estimated between -0.076±0.022×l015 W, produced by mean southward volume transport in our study area. The residual between local surface heat fluxes and horizontal convergence of heat implies a vertical heat convergence process associated with mesoscale temperature and flow fields.

A review on acidifying treatments for vegetable canned food.

PubMed

Derossi, A; Fiore, A G; De Pilli, T; Severini, C

2011-12-01

As is well known, pasteurization treatments are not sufficient for destroying heat resistance of spore forming microorganisms, which are prevented from germination and growing by pH reducing. So, the acidification process becomes one of the most important pre-treatments for the canning industry. It is commonly applied before pasteurization treatment with the purpose of inhibiting spore germination and for reducing heat resistance of the microorganism, thereby allowing to reduce the time or temperature values of the heat treatment. With the aim to reduce the pH of vegetables several techniques are available but their application is not easy to plan. Often, industries define operative conditions only on the basis of empirical experience, thus increasing the risk of microbial growth or imparting an unpleasant sour taste. With the aim of highlighting the correct plan and management of acidification treatments to reach safety without degrading quality of canned fruit and vegetables, the topics that are reviewed and discussed are the effects of low pH on heat resistance of the most important microorganisms, acidification techniques and significant process variables, the effect of low pH on sensorial properties, and future trends.

BUNDLE: A Novel Furnace for Performing Controlled Directional Solidification Experiments in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Carrasquillo, Edgar J.; Griffin, Mark R.; Hammond, Monica S.; Johnson, Martin L.; Grugel, R. N.

2000-01-01

NASA Marshall Space Flight Center has developed a novel directional solidification furnace prototype for processing metals and alloys experiments in a microgravity environment. The BUNDLE (Bridgman Unidirectional Dendrite in Liquid Experiment) furnace is intended to accommodate the science requirements of Flight Definition Principle Investigators studying cellular/dendritic growth in aluminum and lead alloys at processing temperatures up to 1200 C. The furnace implements a number of innovative features to achieve high thermal gradients and quench rates in a low-power, light-weight design. These include a pyrolytic boron nitride/graphite composite heating element surrounded by layers of self-supporting refractory metal shielding, and a graphite fiber enhanced cold zone allowing high levels of heat extraction from the sample crucible. Novel to the BUNDLE design is an in-situ helium gas quench capability that ensures rapid freezing of the solidifying region (mushy zone) of the metal sample within the furnace without sample disturbance prior to quenching; this is a stringent requirement for subsequent analysis and understanding of microstructural development. The experiment hardware concept features multiple furnaces that may be "bundled" together so many samples, currently up to eight, can be processed at one time. The design of BUNDLE is flexible enough to be implemented on the Shuttle and Space Station in a number of locations (SpaceHab, Express Rack, MPESS, ISPR, etc). BUNDLE prototype furnaces have directionally solidified and quenched 1cm diameter lead - 5.8 weight percent antimony and aluminum - 4 weight percent copper alloys. Quenching of the mushy zone, as recorded by in-situ thermocouples, occurred on the order of 0.5 seconds or less, a rate within the PI's requirements. Subsequent metallographic examination revealed the solidified microstructure to be, as expected, unidirectional. Both the dendrite tips and the eutectic reaction were planar in nature indicating uniform axial heat flow. Delineation between the growing dendrites and eutectic structure with the "quenched-in" liquid was sharp, attesting to the efficacy of the helium quench. BUNDLE's conception, development, capability, and adaptability are presented (in view of Flight PI's needs and science requirements) through viewgraphs depicting actual hardware, generated thermal analysis, and micrographs prepared from BUNDLE processed, flight-like samples.

BUNDLE - A Novel Furnace for Performing Controlled Directional Solidification Experiments in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Carrasquillo, Edgar J.; Griffin, Mark R.; Hammond, Monica S.; Johnson, Martin L.; Grugel, R. N.

2001-01-01

NASA Marshall Space Flight Center has developed a novel directional solidification furnace prototype for processing metals and alloys experiments in a microgravity environment. The BUNDLE (Bridgman Unidirectional Dendrite in Liquid Experiment) furnace is intended to accommodate the science requirements of Flight Definition Principle Investigators studying cellular/dendritic growth in aluminum and lead alloys at processing temperatures up to 1200 C. The furnace implements a number of innovative features to achieve high thermal gradients and quench rates in a low-power, light-weight design. These include a pyrolytic boron nitride/graphite composite heating element surrounded by layers of self-supporting refractory metal shielding, and a graphite fiber enhanced cold zone allowing high levels of heat extraction from the sample crucible. Novel to the BUNDLE design is an in-situ helium gas quench capability that ensures rapid freezing of the solidifying region (mushy zone) of the metal sample within the furnace without sample disturbance prior to quenching; this is a stringent requirement for subsequent analysis and understanding of microstructural development. The experiment hardware concept features multiple furnaces that may be "bundled" together so many samples, currently up to eight, can be processed at one time. The design of BUNDLE is flexible enough to be implemented on the Shuttle and Space Station in a number of locations (SpaceHab, Express Rack, MPESS, ISPR, etc). BUNDLE prototype furnaces have directionally solidified and quenched 1cm diameter lead - 5.8 weight percent antimony and aluminum - 4 weight percent copper alloys. Quenching of the mushy zone, as recorded by in-situ thermocouples, occurred on the order of 0.5 seconds or less, a rate within the PI's requirements. Subsequent metallographic examination revealed the solidified microstructure to be, as expected, unidirectional. Both the dendrite tips and the eutectic reaction were planar in nature indicating uniform axial heat flow. Delineation between the growing dendrites and eutectic structure with the "quenched-in" liquid was sharp, attesting to the efficacy of the helium quench. BUNDLE's conception, development, capability, and adaptability are presented (in view of Flight PI's needs and science requirements) through viewgraphs depicting actual hardware, generated thermal analysis, and micrographs prepared from BUNDLE processed, flight-like samples.

Heat Exchange in “Human body - Thermal protection - Environment” System

NASA Astrophysics Data System (ADS)

Khromova, I. V.

2017-11-01

This article is devoted to the issues of simulation and calculation of thermal processes in the system called “Human body - Thermal protection - Environment” under low temperature conditions. It considers internal heat sources and convective heat transfer between calculated elements. Overall this is important for the Heat Transfer Theory. The article introduces complex heat transfer calculation method and local thermophysical parameters calculation method in the system called «Human body - Thermal protection - Environment», considering passive and active thermal protections, thermophysical and geometric properties of calculated elements in a wide range of environmental parameters (water, air). It also includes research on the influence that thermal resistance of modern materials, used in special protective clothes development, has on heat transfer in the system “Human body - Thermal protection - Environment”. Analysis of the obtained results allows adding of the computer research data to experiments and optimizing of individual life-support system elements, which are intended to protect human body from exposure to external factors.

Thermal stability analysis of a superconducting magnet considering heat flow between magnet surface and liquid helium

NASA Astrophysics Data System (ADS)

Jang, J. Y.; Hwang, Y. J.; Ahn, M. C.; Choi, Y. S.

2018-07-01

This paper represents a numerical calculation method that enables highly-accurate simulations on temperature analysis of superconducting magnets considering the heat flow between the magnet and liquid helium during a quench. A three-dimensional (3D) superconducting magnet space was divided into many cells and the finite-difference method (FDM) was adopted to calculate the superconducting magnet temperatures governed by the heat transfer and joule heating of the each cell during a quench. To enhance the accuracy of the temperature calculations during a quench, the heat flow between the superconducting magnet surface and liquid helium, which lowers the magnet temperatures, was considered in this work. The electrical equation coupled with the governing thermal equation was also applied to calculate the change of the decay of the magnet current related to the joule heating. The proposed FDM method for temperatures calculation of a superconducting magnet during a quench process achieved results that were in good agreement with those obtained from an experiment.

Process optimization of an auger pyrolyzer with heat carrier using response surface methodology.

PubMed

Brown, J N; Brown, R C

2012-01-01

A 1 kg/h auger reactor utilizing mechanical mixing of steel shot heat carrier was used to pyrolyze red oak wood biomass. Response surface methodology was employed using a circumscribed central composite design of experiments to optimize the system. Factors investigated were: heat carrier inlet temperature and mass flow rate, rotational speed of screws in the reactor, and volumetric flow rate of sweep gas. Conditions for maximum bio-oil and minimum char yields were high flow rate of sweep gas (3.5 standard L/min), high heat carrier temperature (∼600 °C), high auger speeds (63 RPM) and high heat carrier mass flow rates (18 kg/h). Regression models for bio-oil and char yields are described including identification of a novel interaction effect between heat carrier mass flow rate and auger speed. Results suggest that auger reactors, which are rarely described in literature, are well suited for bio-oil production. The reactor achieved liquid yields greater than 73 wt.%. Copyright © 2011 Elsevier Ltd. All rights reserved.

High Energy Antimatter Telescope (HEAT) Balloon Experiment

NASA Technical Reports Server (NTRS)

Beatty, J. J.

1995-01-01

This grant supported our work on the High Energy Antimatter Telescope(HEAT) balloon experiment. The HEAT payload is designed to perform a series of experiments focusing on the cosmic ray positron, electron, and antiprotons. Thus far two flights of the HEAT -e+/- configuration have taken place. During the period of this grant major accomplishments included the following: (1) Publication of the first results of the 1994 HEAT-e+/- flight in Physical Review Letters; (2) Successful reflight of the HEAT-e+/- payload from Lynn Lake in August 1995; (3) Repair and refurbishment of the elements of the HEAT payload damaged during the landing following the 1995 flight; and (4) Upgrade of the ground support equipment for future flights of the HEAT payload.

Effect of heating on the suppression of tearing modes in tokamaks.

PubMed

Classen, I G J; Westerhof, E; Domier, C W; Donné, A J H; Jaspers, R J E; Luhmann, N C; Park, H K; van de Pol, M J; Spakman, G W; Jakubowski, M W

2007-01-19

The suppression of (neoclassical) tearing modes is of great importance for the success of future fusion reactors like ITER. Electron cyclotron waves can suppress islands, both by driving noninductive current in the island region and by heating the island, causing a perturbation to the Ohmic plasma current. This Letter reports on experiments on the TEXTOR tokamak, investigating the effect of heating, which is usually neglected. The unique set of tools available on TEXTOR, notably the dynamic ergodic divertor to create islands with a fully known driving term, and the electron cyclotron emission imaging diagnostic to provide detailed 2D electron temperature information, enables a detailed study of the suppression process and a comparison with theory.

PBDEs emission from waste printed wiring boards during thermal process.

PubMed

Guo, Jie; Zhang, Ran; Xu, Zhenming

2015-03-03

Polybrominated diphenyl ethers (PBDEs) contained in waste printed wiring board (PWB) matrix and surface dust can be emitted into the air during thermal process, which is widely used to detach the electronic components from the base boards of waste PWB. In this study, PBDEs concentrations in air and dust samples were detected in a PWB-heating workshop, and then heating experiments of PBDEs-containing materials in a quartz tube furnace were performed to investigate the PBDEs emission mechanism. The results showed that the mean concentrations of Σ8PBDEs in PM10 and TSP were 479 and 1670 ng/m(3), respectively. Compared with surface dust collected from waste PWB (15600 ng/g), PBDEs concentrations in dust from the workshop floor (31,100 ng/g), heating machine inside (84,700 ng/g), and the cyclone extractor (317,000 ng/g), were condensed after thermal process. Heating experiments showed that the emission rates of PBDEs from PBDEs-containing dust were obviously higher than those from PWB fragments in the first 1-h time. The cumulative amounts of PBDEs emitted from dust increased rapidly at first, and then leveled off to become asymptotic to the maximum amounts. At the temperature of 300 °C, the PBDEs emission from dust mainly occurred within the first 5 min, and the average emission rates for BDE-28, -47, and -99 among the first 5 min were 1230, 4480, and 1950 ng/(g·min), respectively. During the initial 1-h period, the trends of PBDEs emission from PWB fragments had a linear increase, and the emission rates of penta-BDE (BDE-47, -99, -100) at different temperatures were at a range of 9.75-11.5 ng/(g·min). All the results showed that PBDEs emission from PWB waste happened during thermal process, and management strategies were provided to reduce the occupational exposure level of PBDEs for workers.

Comparing the transient response of a resistive-type sensor with a thin film thermocouple during the post-exposure bake process

NASA Astrophysics Data System (ADS)

Kreider, Kenneth G.; DeWitt, David P.; Fowler, Joel B.; Proctor, James E.; Kimes, William A.; Ripple, Dean C.; Tsai, Benjamin K.

2004-04-01

Recent studies on dynamic temperature profiling and lithographic performance modeling of the post-exposure bake (PEB) process have demonstrated that the rate of heating and cooling may have an important influence on resist lithographic response. Measuring the transient surface temperature during the heating or cooling process with such accuracy can only be assured if the sensors embedded in or attached to the test wafer do not affect the temperature distribution in the bare wafer. In this paper we report on an experimental and analytical study to compare the transient response of embedded platinum resistance thermometer (PRT) sensors with surface-deposited, thin-film thermocouples (TFTC). The TFTCs on silicon wafers have been developed at NIST to measure wafer temperatures in other semiconductor thermal processes. Experiments are performed on a test bed built from a commercial, fab-qualified module with hot and chill plates using wafers that have been instrumented with calibrated type-E (NiCr/CuNi) TFTCs and commercial PRTs. Time constants were determined from an energy-balance analysis fitting the temperature-time derivative to the wafer temperature during the heating and cooling processes. The time constants for instrumented wafers ranged from 4.6 s to 5.1 s on heating for both the TFTC and PRT sensors, with an average difference less than 0.1 s between the TFTCs and PRTs and slightly greater differences on cooling.

Influence of heating and acidification on the flavor of whey protein isolate.

PubMed

White, S S; Fox, K M; Jervis, S M; Drake, M A

2013-03-01

Previous studies have established that whey protein manufacture unit operations influence the flavor of dried whey proteins. Additionally, manufacturers generally instantize whey protein isolate (WPI; ≥ 90% protein) by agglomeration with lecithin to increase solubility and wettability. Whey protein isolate is often subjected to additional postprocessing steps in beverage manufacturing, including acidification and heat treatment. These postprocessing treatments may further influence formation or release of flavors. The objective of the first study was to characterize the effect of 2 processing steps inherent to manufacturing of acidic protein beverages (acidification and heat treatment) on the flavor of non-instant WPI. The second study sought to determine the effect of lecithin agglomeration, a common form of instantized (INST) WPI used in beverage manufacturing, on the flavor of WPI after acidification and heat treatment. In the first experiment, commercial non-instantized (NI) WPI were rehydrated and evaluated as is (control); acidified to pH 3.2; heated to 85°C for 5 min in a benchtop high temperature, short time (HTST) pasteurizer; or acidified to 3.2 and heated to 85°C for 30s (AH-HTST). In the second experiment, INST and NI commercial WPI were subsequently evaluated as control, acidified, heated, or AH-HTST. All samples were evaluated by descriptive sensory analysis, solid-phase microextraction (SPME), and gas chromatography-mass spectrometry. Acidification of NI WPI produced higher concentrations of dimethyl disulfide (DMDS) and sensory detection of potato/brothy flavors, whereas heating increased cooked/sulfur flavors. Acidification and heating increased cardboard, potato/brothy, and malty flavors and produced higher concentrations of aldehydes, ketones, and sulfur compounds. Differences between INST and NI WPI existed before treatment; INST WPI displayed cucumber flavors not present in NI WPI. After acidification, INST WPI were distinguished by higher intensity of cucumber flavor and higher concentrations of E-2-nonenal. No perceivable differences were observed between INST and NI WPI after heating; sulfur and eggy flavors increased in both types of WPI. After treatment, AH-INST-HTST samples were differentiated from AH-NI-HTST by grassy/hay and grainy flavor and increased lipid oxidation products. Further processing of WPI in food applications has negative effects on the flavor contributions of WPI. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The space shuttle payload planning working groups: Volume 9: Materials processing and space manufacturing

NASA Technical Reports Server (NTRS)

1973-01-01

The findings and recommendations of the Materials Processing and Space Manufacturing group of the space shuttle payload planning activity are presented. The effects of weightlessness on the levitation processes, mixture stability, and control over heat and mass transport in fluids are considered for investigation. The research and development projects include: (1) metallurgical processes, (2) electronic materials, (3) biological applications, and (4)nonmetallic materials and processes. Additional recommendations are provided concerning the allocation of payload space, acceptance of experiments for flight, flight qualification, and private use of the space shuttle.

ORGANIZATION 6, NOVA SCIENCE UNIT 7.

ERIC Educational Resources Information Center

1964

DIRECTIONS FOR CONDUCTING A SERIES OF SCIENCE EXPERIMENTS ARE PRESENTED. THE EXPERIMENTS CONCERN THE STUDY OF HEAT AND MOLECULAR MOTION, HEAT EXCHANGE IN A MIXTURE, SPECIFIC HEAT, HEAT AND SIZE, EXPANSION OF LIQUID, EXPANSION OF AIR, HEAT OF FUSION OF ICE, HEAT OF VAPORIZATION OF WATER, LIGHT AND SOUND, LAW OF REFLECTION, PLANE MIRROR IMAGES,…

Effects of latent heat in various cloud microphysics processes on autumn rainstorms with different intensities on Hainan Island, China

NASA Astrophysics Data System (ADS)

Li, Jiangnan; Wu, Kailu; Li, Fangzhou; Chen, Youlong; Huang, Yanbin; Feng, YeRong

2017-06-01

In this study, we used the Weather Research and Forecasting (WRF) and WRF-3DVAR models to perform a series of simulations of two autumn rainstorms on Hainan Island. The results of neighborhood fractions and Hanssen skill scoring (FSS, HSS) methods show that the control experiments reproduced well two heavy rainfall episodes. Effects of latent heat in various cloud microphysical processes are different at distinct intensities or stages of precipitation. In the absence of any heating effect of deposition, precipitation weakened. The greater was the precipitation, the more significant was the weakening effect. Ascending movement at upper troposphere could be weakened or descending movement at lower troposphere enhanced. With decreases in the strength of precipitation, cloud ice, snow, graupel, and rainwater, increases in latent heat lessened. With weak precipitation, at upper troposphere the rainwater content increased and snow and ice content decreased, whereas at middle troposphere, the ice, snow, and graupel contents increased. Latent heating increased at middle and lower troposphere and decreased at upper troposphere. The absence of any heating effect of freezing had little effect on precipitation. By removing the evaporative cooling of cloud water, the interactions between vertical movement and cloud microphysical processes resulted in a weakening of strong precipitation and an intensification of weak precipitation. However, in the preliminary stages of these two precipitation events, snow, graupel, cloud ice, and rainwater all increased, and precipitation was enhanced in both. In the later stages, strong precipitation systems weakened and weak precipitation systems strengthened. Latent heating first increased and then dropped in strong precipitation systems, whereas they continuously increased in weak precipitation systems.

Effect of steam generator configuration in a loss of the RHR during mid-loop operation at PKL facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villanueva, J. F.; Carlos, S.; Martorell, S.

The loss of the residual heat removal system in mid-loop conditions may occur with a non-negligible contribution to the plant risk, so the analysis of the accidental sequences and the actions to mitigate the accident are of great interest in shutdown conditions. In order to plan the appropriate measures to mitigate the accident is necessary to understand the thermal-hydraulic processes following the loss of the residual heat removal system during shutdown. Thus, transients of this kind have been simulated using best-estimate codes in different integral test facilities and compared with experimental data obtained in different facilities. In PKL (Primaerkreislauf-Versuchsanlage, primarymore » coolant loop test facility) test facility different series of experiments have been undertaken to analyze the plant response in shutdown. In this context, the E3 and F2 series consist of analyzing the loss of the residual heat removal system with a reduced inventory in the primary system. In particular, the experiments were developed to investigate the influence of the steam generators secondary side configuration on the plant response, what involves the consideration of different number of steam generators filled with water and ready for activation, on the heat transfer mechanisms inside the steam generators U-tubes. This work presents the results of such experiments calculated using, RELAP5/Mod 3.3. (authors)« less

Ceramic processing: Experimental design and optimization

NASA Technical Reports Server (NTRS)

Weiser, Martin W.; Lauben, David N.; Madrid, Philip

1992-01-01

The objectives of this paper are to: (1) gain insight into the processing of ceramics and how green processing can affect the properties of ceramics; (2) investigate the technique of slip casting; (3) learn how heat treatment and temperature contribute to density, strength, and effects of under and over firing to ceramic properties; (4) experience some of the problems inherent in testing brittle materials and learn about the statistical nature of the strength of ceramics; (5) investigate orthogonal arrays as tools to examine the effect of many experimental parameters using a minimum number of experiments; (6) recognize appropriate uses for clay based ceramics; and (7) measure several different properties important to ceramic use and optimize them for a given application.

Improved silicon carbide for advanced heat engines

NASA Technical Reports Server (NTRS)

Whalen, Thomas J.

1988-01-01

This is the third annual technical report for the program entitled, Improved Silicon Carbide for Advanced Heat Engines, for the period February 16, 1987 to February 15, 1988. The objective of the original program was the development of high strength, high reliability silicon carbide parts with complex shapes suitable for use in advanced heat engines. Injection molding is the forming method selected for the program because it is capable of forming complex parts adaptable for mass production on an economically sound basis. The goals of the revised program are to reach a Weibull characteristic strength of 550 MPa (80 ksi) and a Weibull modulus of 16 for bars tested in 4-point loading. Two tasks are discussed: Task 1 which involves materials and process improvements, and Task 2 which is a MOR bar matrix to improve strength and reliability. Many statistically designed experiments were completed under task 1 which improved the composition of the batches, the mixing of the powders, the sinter and anneal cycles. The best results were obtained by an attritor mixing process which yielded strengths in excess of 550 MPa (80 ksi) and an individual Weibull modulus of 16.8 for a 9-sample group. Strengths measured at 1200 and 1400 C were equal to the room temperature strength. Annealing of machined test bars significantly improved the strength. Molding yields were measured and flaw distributions were observed to follow a Poisson process. The second iteration of the Task 2 matrix experiment is described.

Investigation on microwave heating for direct leaching of chalcopyrite ores and concentrates

NASA Astrophysics Data System (ADS)

Onol, Kubra; Saridede, Muhlis Nezihi

2013-03-01

The use of microwave energy in materials processing is a relatively new development presenting numerous advantages because of the rapid heating feature. Microwave technology has great potential to improve the extraction efficiency of metals in terms of both a reduction in required leaching time and an increase in the recovery of valuable metals. This method is especially pertinent in view of the increased demand for environment-friendly processes. In the present study, the influence of microwave heating on the direct leaching of chalcopyrite ores and concentrates were investigated. The results of microwave leaching experiments were compared with those obtained under conventional conditions. During these processes, parameters such as leaching media, temperature, and time have been worked to determine the optimum conditions for proper copper dissolution. Experimental results show that microwave leaching is more efficient than conventional leaching. The optimum leaching conditions for microwave leaching are the solid-to-liquid ratio of 1:100 g/mL, the temperature of 140°C, the solution of 0.5 M H2SO4 + 0.05 M Fe2(SO4)3, and the time of 1 h.

Undergraduate Laboratory on a Turbulent Impinging Jet

NASA Astrophysics Data System (ADS)

Ivanosky, Arnaud; Brezzard, Etienne; van Poppel, Bret; Benson, Michael

2017-11-01

An undergraduate thermal sciences laboratory exercise that includes both experimental fluid mechanics and heat transfer measurements of an impinging jet is presented. The flow field is measured using magnetic resonance velocimetry (MRV) of a water flow, while IR thermography is used in the heat transfer testing. Flow Reynolds numbers for both the heat transfer and fluid mechanics tests range from 20,000-50,000 based on the jet diameter for a fully turbulent flow condition, with target surface temperatures in the heat transfer test reaching a maximum of approximately 50 Kelvin. The heat transfer target surface is subject to a measured uniform Joule heat flux, a well-defined boundary condition that allows comparison to existing correlations. The MRV generates a 3-component 3-dimensional data set, while the IR thermography provides a 2-dimensional heat transfer coefficient (or Nusselt number) map. These data sets can be post-processed and compared to existing correlations to verify data quality, and the sets can be juxtaposed to understand how flow features drive heat transfer. The laboratory setup, data acquisition, and analysis procedures are described for the laboratory experience, which can be incorporated as fluid mechanics, experimental methods, and heat transfer courses

Extreme learning machine: a new alternative for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters.

PubMed

Liu, Zhijian; Li, Hao; Tang, Xindong; Zhang, Xinyu; Lin, Fan; Cheng, Kewei

2016-01-01

Heat collection rate and heat loss coefficient are crucial indicators for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, wasting too much time and manpower. To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by "portable test instruments" as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing.

Optimization of torrefaction conditions of coffee industry residues using desirability function approach.

PubMed

Buratti, C; Barbanera, M; Lascaro, E; Cotana, F

2018-03-01

The aim of the present study is to analyze the influence of independent process variables such as temperature, residence time, and heating rate on the torrefaction process of coffee chaff (CC) and spent coffee grounds (SCGs). Response surface methodology and a three-factor and three-level Box-Behnken design were used in order to evaluate the effects of the process variables on the weight loss (W L ) and the Higher Heating Value (HHV) of the torrefied materials. Results showed that the effects of the three factors on both responses were sequenced as follows: temperature>residence time>heating rate. Data obtained from the experiments were analyzed by analysis of variance (ANOVA) and fitted to second-order polynomial models by using multiple regression analysis. Predictive models were determined, able to obtain satisfactory fittings of the experimental data, with coefficient of determination (R 2 ) values higher than 0.95. An optimization study using Derringer's desired function methodology was also carried out and the optimal torrefaction conditions were found: temperature 271.7°C, residence time 20min, heating rate 5°C/min for CC and 256.0°C, 20min, 25°C/min for SCGs. The experimental values closely agree with the corresponding predicted values. Copyright © 2017 Elsevier Ltd. All rights reserved.

Process-level model evaluation: a snow and heat transfer metric

NASA Astrophysics Data System (ADS)

Slater, Andrew G.; Lawrence, David M.; Koven, Charles D.

2017-04-01

Land models require evaluation in order to understand results and guide future development. Examining functional relationships between model variables can provide insight into the ability of models to capture fundamental processes and aid in minimizing uncertainties or deficiencies in model forcing. This study quantifies the proficiency of land models to appropriately transfer heat from the soil through a snowpack to the atmosphere during the cooling season (Northern Hemisphere: October-March). Using the basic physics of heat diffusion, we investigate the relationship between seasonal amplitudes of soil versus air temperatures due to insulation from seasonal snow. Observations demonstrate the anticipated exponential relationship of attenuated soil temperature amplitude with increasing snow depth and indicate that the marginal influence of snow insulation diminishes beyond an effective snow depth of about 50 cm. A snow and heat transfer metric (SHTM) is developed to quantify model skill compared to observations. Land models within the CMIP5 experiment vary widely in SHTM scores, and deficiencies can often be traced to model structural weaknesses. The SHTM value for individual models is stable over 150 years of climate, 1850-2005, indicating that the metric is insensitive to climate forcing and can be used to evaluate each model's representation of the insulation process.

Process-level model evaluation: a snow and heat transfer metric

DOE PAGES

Slater, Andrew G.; Lawrence, David M.; Koven, Charles D.

2017-04-20

Land models require evaluation in order to understand results and guide future development. Examining functional relationships between model variables can provide insight into the ability of models to capture fundamental processes and aid in minimizing uncertainties or deficiencies in model forcing. This study quantifies the proficiency of land models to appropriately transfer heat from the soil through a snowpack to the atmosphere during the cooling season (Northern Hemisphere: October–March). Using the basic physics of heat diffusion, we investigate the relationship between seasonal amplitudes of soil versus air temperatures due to insulation from seasonal snow. Observations demonstrate the anticipated exponential relationshipmore » of attenuated soil temperature amplitude with increasing snow depth and indicate that the marginal influence of snow insulation diminishes beyond an effective snow depth of about 50 cm. A snow and heat transfer metric (SHTM) is developed to quantify model skill compared to observations. Land models within the CMIP5 experiment vary widely in SHTM scores, and deficiencies can often be traced to model structural weaknesses. The SHTM value for individual models is stable over 150 years of climate, 1850–2005, indicating that the metric is insensitive to climate forcing and can be used to evaluate each model's representation of the insulation process.« less

Process-level model evaluation: a snow and heat transfer metric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slater, Andrew G.; Lawrence, David M.; Koven, Charles D.

Land models require evaluation in order to understand results and guide future development. Examining functional relationships between model variables can provide insight into the ability of models to capture fundamental processes and aid in minimizing uncertainties or deficiencies in model forcing. This study quantifies the proficiency of land models to appropriately transfer heat from the soil through a snowpack to the atmosphere during the cooling season (Northern Hemisphere: October–March). Using the basic physics of heat diffusion, we investigate the relationship between seasonal amplitudes of soil versus air temperatures due to insulation from seasonal snow. Observations demonstrate the anticipated exponential relationshipmore » of attenuated soil temperature amplitude with increasing snow depth and indicate that the marginal influence of snow insulation diminishes beyond an effective snow depth of about 50 cm. A snow and heat transfer metric (SHTM) is developed to quantify model skill compared to observations. Land models within the CMIP5 experiment vary widely in SHTM scores, and deficiencies can often be traced to model structural weaknesses. The SHTM value for individual models is stable over 150 years of climate, 1850–2005, indicating that the metric is insensitive to climate forcing and can be used to evaluate each model's representation of the insulation process.« less

Large-scale boiling experiments of the flooded cavity concept for in-vessel core retention

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, T.Y.; Slezak, S.E.; Bentz, J.H.

1994-03-01

This paper presents results of ex-vessel boiling experiments performed in the CYBL (CYlindrical BoiLing) facility. CYBL is a reactor-scale facility for confirmatory research of the flooded cavity concept for accident management. CYBL has a tank-within-a-tank design; the inner tank simulates the reactor vessel and the outer tank simulates the reactor cavity. Experiments with uniform and edge-peaked heat flux distributions up to 20 W/cm{sup 2} across the vessel bottom were performed. Boiling outside the reactor vessel was found to be subcooled nucleate boiling. The subcooling is mainly due to the gravity head which results from flooding the sides of the reactormore » vessel. The boiling process exhibits a cyclic pattern with four distinct phases: direct liquid/solid contact, bubble nucleation and growth, coalescence, and vapor mass dispersion (ejection). The results suggest that under prototypic heat load and heat flux distributions, the flooded cavity in a passive pressurized water reactor like the AP-600 should be capable of cooling the reactor pressure vessel in the central region of the lower head that is addressed by these tests.« less

Brain mediators of predictive cue effects on perceived pain

PubMed Central

Atlas, Lauren Y.; Bolger, Niall; Lindquist, Martin A.; Wager, Tor D.

2010-01-01

Information about upcoming pain strongly influences pain experience in experimental and clinical settings, but little is known about the brain mechanisms that link expectation and experience. To identify the pathways by which informational cues influence perception, analyses must jointly consider both the effects of cues on brain responses and the relationship between brain responses and changes in reported experience. Our task and analysis strategy were designed to test these relationships. Auditory cues elicited expectations for low or high painful thermal stimulation, and we assessed how cues influenced human subjects’ pain reports and BOLD fMRI responses to matched levels of noxious heat. We used multi-level mediation analysis to identify brain regions that 1) are modulated by predictive cues, 2) predict trial-to-trial variations in pain reports, and 3) formally mediate the relationship between cues and reported pain. Cues influenced heat-evoked responses in most canonical pain-processing regions, including both medial and lateral pain pathways. Effects on several regions correlated with pre-task expectations, suggesting that expectancy plays a prominent role. A subset of pain-processing regions, including anterior cingulate cortex, anterior insula, and thalamus, formally mediated cue effects on pain. Effects on these regions were in turn mediated by cue-evoked anticipatory activity in the medial orbitofrontal cortex (OFC) and ventral striatum, areas not previously directly implicated in nociception. These results suggest that activity in pain-processing regions reflects a combination of nociceptive input and top-down information related to expectations, and that anticipatory processes in OFC and striatum may play a key role in modulating pain processing. PMID:20881115

Cryogenic Heat Pipe Experiment (CRYOHP)

NASA Technical Reports Server (NTRS)

Mcintosh, Roy

1992-01-01

The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios

DTIC Science & Technology

1999-07-01

handled as a dry solid. This approach was recommended by vendors and is typical of dewatering equipment used in the utility flue gas desulfurization ...in a large continuous stirred- tank reactor (CSTR). 21 H. Majdeski, personal experience in the flue gas desulfurization industry, 1998. 22 Letter to B...defined as the percentage of the feed heat that is converted to steam heat, is 62% (see Figure 15). Flue gas from the dryer cyclone enters a baghouse to

An empirical investigation on thermal characteristics and pressure drop of Ag-oil nanofluid in concentric annular tube

NASA Astrophysics Data System (ADS)

Abbasian Arani, A. A.; Aberoumand, H.; Aberoumand, S.; Jafari Moghaddam, A.; Dastanian, M.

2016-08-01

In this work an experimental study on Silver-oil nanofluid was carried out in order to present the laminar convective heat transfer coefficient and friction factor in a concentric annulus with constant heat flux boundary condition. Silver-oil nanofluid prepared by Electrical Explosion of Wire technique with no nanoparticles agglomeration during nanofluid preparation process and experiments. The average sizes of particles were 20 nm. Nanofluids with various particle Volume fractions of 0.011, 0.044 and 0.171 vol% were employed. The nanofluid flowing between the tubes is heated by an electrical heating coil wrapped around it. The effects of different parameters such as flow Reynolds number, tube diameter ratio and nanofluid particle concentration on heat transfer coefficient are studied. Results show that, heat transfer coefficient increased by using nanofluid instead of pure oil. Maximum enhancement of heat transfer coefficient occurs in 0.171 vol%. In addition the results showed that, there are slight increases in pressure drop of nanofluid by increasing the nanoparticle concentration of nanofluid in compared to pure oil.

Sensor fault detection and isolation via high-gain observers: application to a double-pipe heat exchanger.

PubMed

Escobar, R F; Astorga-Zaragoza, C M; Téllez-Anguiano, A C; Juárez-Romero, D; Hernández, J A; Guerrero-Ramírez, G V

2011-07-01

This paper deals with fault detection and isolation (FDI) in sensors applied to a concentric-pipe counter-flow heat exchanger. The proposed FDI is based on the analytical redundancy implementing nonlinear high-gain observers which are used to generate residuals when a sensor fault is presented (as software sensors). By evaluating the generated residual, it is possible to switch between the sensor and the observer when a failure is detected. Experiments in a heat exchanger pilot validate the effectiveness of the approach. The FDI technique is easy to implement allowing the industries to have an excellent alternative tool to keep their heat transfer process under supervision. The main contribution of this work is based on a dynamic model with heat transfer coefficients which depend on temperature and flow used to estimate the output temperatures of a heat exchanger. This model provides a satisfactory approximation of the states of the heat exchanger in order to allow its implementation in a FDI system used to perform supervision tasks. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Condensation on Highly Superheated Surfaces: Unstable Thin Films in a Wickless Heat Pipe.

PubMed

Kundan, Akshay; Nguyen, Thao T T; Plawsky, Joel L; Wayner, Peter C; Chao, David F; Sicker, Ronald J

2017-03-03

A wickless heat pipe was operated on the International Space Station to provide a better understanding of how the microgravity environment might alter the physical and interfacial forces driving evaporation and condensation. Traditional heat pipes are divided into three zones: evaporation at the heated end, condensation at the cooled end, and intermediate or adiabatic in between. The microgravity experiments reported herein show that the situation may be dramatically more complicated. Beyond a threshold heat input, there was a transition from evaporation at the heated end to large-scale condensation, even as surface temperatures exceeded the boiling point by 160 K. The hotter the surface, the more vapor was condensed onto it. The condensation process at the heated end is initiated by thickness and temperature disturbances in the thin liquid film that wet the solid surface. Those disturbances effectively leave the vapor "superheated" in that region. Condensation is amplified and sustained by the high Marangoni stresses that exist near the heater and that drive liquid to cooler regions of the device.

Modeling the pyrolysis study of non-charring polymers under reduced pressure environments

NASA Astrophysics Data System (ADS)

Zong, Ruowen; Kang, Ruxue; Hu, Yanghui; Zhi, Youran

2018-04-01

In order to study the pyrolysis of non-charring polymers under reduced pressure environments, a series of experiments based on black acrylonitrile butadiene styrene (ABS) was conducted in a reduced pressure chamber under different external heat fluxes. The temperatures of the top surface and the bottom of the sample and the mass loss during the whole process were measured in real time. A one-dimensional numerical model was developed to predict the top surface and the bottom surface temperatures of ABS during the pyrolysis at different reduced pressures and external heat fluxes, and the model was validated by the experimental data. The results of the study indicate that the profiles of the top surface and the bottom surface temperatures are different at different pressures and heat fluxes. The temperature and the mass loss rate of the sample under a lower heat flux decreased significantly as the pressure was increased. However, under a higher heat flux, the temperature and the mass loss rate showed little sensitivity to the pressure. The simulated results fitted the experimental results better at the higher heat flux than at the lower heat flux.

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE PAGES

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry; ...

2018-05-19

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. Experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Origin of temperature plateaus in laser-heated diamond anvil cell experiments

NASA Astrophysics Data System (ADS)

Geballe, Zachary M.; Jeanloz, Raymond

2012-06-01

Many high-pressure high-temperature studies using laser-heated diamond cells have documented plateaus in the increase of temperature with increasing laser power or with time. By modeling heat transfer in typical laser-heated diamond anvil cell experiments, we demonstrate that latent heat due to melting or other phase transformation is unlikely to be the source of observed plateaus in any previously published studies, regardless of whether pulsed or continuous lasers were used. Rather, large increases (˜10-fold) in thermal conductivity can explain some of the plateaus, and modest increases in reflectivity (tens of percent) can explain any or all of them. Modeling also shows that the sub-microsecond timescale of heating employed in recent pulsed heating experiments is fast enough compared to heat transport into and through typical insulations, but too slow compared to heat transport into metallic laser absorbers themselves to allow the detection of a large plateau due to latent heat of fusion. Four new designs are suggested for future experiments that could use the simple observation of a latent heat-induced plateau to provide reliable high-pressure melting data.

Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

NASA Technical Reports Server (NTRS)

Berisford, Daniel F.; Birur, Gajanana C.; Miller, Jennifer R.; Sunada, Eric T.; Ganapathi, Gani B.; Stephan, Ryan; Johnson, Mark

2011-01-01

The digital radiator technology is one of three variable heat rejection technologies being investigated for future human-rated NASA missions. The digital radiator concept is based on a mechanically pumped fluid loop with parallel tubes carrying coolant to reject heat from the radiator surface. A series of valves actuate to start and stop fluid flow to di erent combinations of tubes, in order to vary the heat rejection capability of the radiator by a factor of 10 or more. When the flow in a particular leg is stopped, the fluid temperature drops and the fluid can freeze, causing damage or preventing flow from restarting. For this reason, the liquid in a stopped leg must be partially or fully evacuated upon shutdown. One of the challenges facing fluid evacuation from closed tubes arises from the vapor generated during pumping to low pressure, which can cause pump cavitation and incomplete evacuation. Here we present a series of laboratory experiments demonstrating fluid evacuation techniques to overcome these challenges by applying heat and pumping to partial vacuum. Also presented are results from qualitative testing of the freezing characteristics of several different candidate fluids, which demonstrate significant di erences in freezing properties, and give insight to the evacuation process.

The concept and science process skills analysis in bomb calorimeter experiment as a foundation for the development of virtual laboratory of bomb calorimeter

NASA Astrophysics Data System (ADS)

Kurniati, D. R.; Rohman, I.

2018-05-01

This study aims to analyze the concepts and science process skills in bomb calorimeter experiment as a basis for developing the virtual laboratory of bomb calorimeter. This study employed research and development method (R&D) to gain the answer to the proposed problems. This paper discussed the concepts and process skills analysis. The essential concepts and process skills associated with bomb calorimeter are analyze by optimizing the bomb calorimeter experiment. The concepts analysis found seven fundamental concepts to be concerned in developing the virtual laboratory that are internal energy, burning heat, perfect combustion, incomplete combustion, calorimeter constant, bomb calorimeter, and Black principle. Since the concept of bomb calorimeter, perfect and incomplete combustion created to figure out the real situation and contain controllable variables, in virtual the concepts displayed in the form of simulation. Meanwhile, the last four concepts presented in the form of animation because no variable found to be controlled. The process skills analysis detect four notable skills to be developed that are ability to observe, design experiment, interpretation, and communication skills.

The single grain fusion dating approach: Determining the factors that control white mica 40Ar/39Ar age formation during HP metamorphism of the Cycladic Blueschist Unit, Greece

NASA Astrophysics Data System (ADS)

Uunk, Bertram; Wijbrans, Jan; Brouwer, Fraukje

2017-04-01

White mica 40Ar/39Ar dating is a proven powerful tool for constraining the timing and rate of metamorphism, deformation and exhumation. However, for high-pressure metamorphic rocks dating often results in wide age ranges, which are not in agreement with constraints from other isotopic systems, indicating that geological and chemical processes complicate straightforward 40Ar/39Ar dating. Despite hosting one of the largest geochronological datasets in the world, the Cycladic Blueschist Unit in Greece is presently one of the focal areas in the discussion on the interpretation of metamorphic 40Ar/39Ar ages. Previous phengite multi grain step heating experiments commonly yielded undulating age spectra ranging between 20 - 60 Ma. While some studies attempt to assign geological significance to these ages, others argue the ages are geologically meaningless and the result of the interplay between partial diffusive resetting and continued crystallization. By taking an alternative approach of multiple single grain fusion experiments, this study investigates age heterogeneity between samples of contrasting metamorphic facies, rheology and strain from the Cycladic islands of Syros and Sifnos. Comparing the size and shape of single grain fusion age distributions at the grain, rock, outcrop and island scale allows determination of the scale at which different age-forming processes operate. Resulting ages show a previously unreported consistent variation between different outcrops, moving from the eclogite-blueschist facies (55-45 Ma) to greenschist overprinting (40-30 Ma). This indicates that outcrop scale homogeneous resetting is the dominant processes for age formation in the CBU. Single grain age variation at the sample and outcrop scale is only limited to 10 Ma, indicating a smaller but observable role for local age perturbing processes of incomplete resetting, continued (re)crystallization or infiltration of excess argon. Some of the partially overprinted samples show homogeneous single grain age populations, indicating at least a partial role for efficient resetting by thermally activated diffusion at the outcrop scale. Traditional multi grain step heating experiments on the same samples yield flat plateaus for various single grain age distributions, indicating that age heterogeneities resolved by single grain fusion dating are mixed to a meaningless average in step heating experiments. In contrast, our approach leads to a better understanding of the processes responsible for age formation during high pressure metamorphism.

Containerless Liquid-Phase Processing of Ceramic Materials

NASA Technical Reports Server (NTRS)

Weber, J. K. Richard (Principal Investigator); Nordine, Paul C.

1996-01-01

The present project builds on the results of research supported under a previous NASA grant to investigate containerless liquid-phase processing of molten ceramic materials. The research used an aero-acoustic levitator in combination with cw CO2 laser beam heating to achieve containerless melting, superheating, undercooling, and solidification of poorly-conducting solids and liquids. Experiments were performed on aluminum oxide, binary aluminum oxide-silicon dioxide materials, and oxide superconductors.

Detect the sensitivity and response of protein molecular structure of whole canola seed (yellow and brown) to different heat processing methods and relation to protein utilization and availability using ATR-FT/IR molecular spectroscopy with chemometrics.

PubMed

Samadi; Theodoridou, Katerina; Yu, Peiqiang

2013-03-15

The objectives of this experiment were to detect the sensitivity and response of protein molecular structure of whole canola seed to different heat processing [moisture (autoclaving) vs. dry (roasting) heating] and quantify heat-induced protein molecular structure changes in relation to protein utilization and availability. In this study, whole canola seeds were autoclaved (moisture heating) and dry (roasting) heated at 120 °C for 1h, respectively. The parameters assessed included changes in (1) chemical composition profile, (2) CNCPS protein subfractions (PA, PB1, PB2, PB3, PC), (3) intestinal absorbed true protein supply, (4) energy values, and (5) protein molecular structures (amide I, amide II, ratio of amide I to II, α-helix, β-sheet, ratio of α-helix to β-sheet). The results showed that autoclave heating significantly decreased (P<0.05) but dry heating increased (P<0.05) the ratio of protein α-helix to β-sheet (with the ratios of 1.07, 0.95, 1.10 for the control (raw), autoclave heating and dry heating, respectively). The multivariate molecular spectral analyses (PCA, CLA) showed that there were significantly molecular structural differences in the protein amide I and II fingerprint region (ca. 1714-1480 cm(-1)) among the control, autoclave and dry heating. These differences were indicated by the form of separate class (PCA) and group of separate ellipse (CLA) between the treatments. The correlation analysis with spearman method showed that there were significantly and highly positive correlation (P<0.05) between heat-induced protein molecular structure changes in terms of α-helix to β-sheet ratios and in situ protein degradation and significantly negative correlation between the protein α-helix to β-sheet ratios and intestinal digestibility of undegraded protein. The results indicated that heat-induced changes of protein molecular structure revealed by vibration molecular spectroscopy could be used as a potential predictor to protein degradation and intestinal protein digestion of whole canola seed. Future study is needed to study response and impact of heat processing to each inherent layer of canola seed from outside to inside tissues and between yellow canola and brown canola. Copyright © 2012 Elsevier B.V. All rights reserved.

Resin Film Infusion (RFI) Process Modeling for Large Transport Aircraft Wing Structures

NASA Technical Reports Server (NTRS)

Loos, Alfred C.; Caba, Aaron C.; Furrow, Keith W.

2000-01-01

This investigation completed the verification of a three-dimensional resin transfer molding/resin film infusion (RTM/RFI) process simulation model. The model incorporates resin flow through an anisotropic carbon fiber preform, cure kinetics of the resin, and heat transfer within the preform/tool assembly. The computer model can predict the flow front location, resin pressure distribution, and thermal profiles in the modeled part. The formulation for the flow model is given using the finite element/control volume (FE/CV) technique based on Darcy's Law of creeping flow through a porous media. The FE/CV technique is a numerically efficient method for finding the flow front location and the fluid pressure. The heat transfer model is based on the three-dimensional, transient heat conduction equation, including heat generation. Boundary conditions include specified temperature and convection. The code was designed with a modular approach so the flow and/or the thermal module may be turned on or off as desired. Both models are solved sequentially in a quasi-steady state fashion. A mesh refinement study was completed on a one-element thick model to determine the recommended size of elements that would result in a converged model for a typical RFI analysis. Guidelines are established for checking the convergence of a model, and the recommended element sizes are listed. Several experiments were conducted and computer simulations of the experiments were run to verify the simulation model. Isothermal, non-reacting flow in a T-stiffened section was simulated to verify the flow module. Predicted infiltration times were within 12-20% of measured times. The predicted pressures were approximately 50% of the measured pressures. A study was performed to attempt to explain the difference in pressures. Non-isothermal experiments with a reactive resin were modeled to verify the thermal module and the resin model. Two panels were manufactured using the RFI process. One was a stepped panel and the other was a panel with two 'T' stiffeners. The difference between the predicted infiltration times and the experimental times was 4% to 23%.

The effect of methanogenesis inhibition, inoculum and substrate concentration on hydrogen and carboxylic acids production from cassava wastewater.

PubMed

Amorim, Norma C S; Amorim, Eduardo L C; Kato, Mario T; Florencio, Lourdinha; Gavazza, Savia

2018-02-01

Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2.3-L flasks during two operational phases. In the first phase (P1), inhibition of methanogens in the sludge was evaluated using acetylene (1% v/v of headspace) and heat treatment (120 °C, 1 atm for 30 min). In the second phase (P2), three inoculum types obtained from common anaerobic sludges (bovine rumen and sludges from municipal and textile industrial wastewater treatment plants) were individually assayed. P2 aimed to identify the best inoculum, based on hydrogen production ability, which was tested for three initial concentrations of manipueira in terms of chemical oxygen demand (COD) (10, 20 and 40 g O 2 /L). Results of P1 indicated that either acetylene or heat treatment efficiently inhibited methanogenesis, with no methane production. However, the maximum H 2 production potential by applying heat treatment (~ 563 mL) was more than twice compared with that by acetylene treatment (~ 257 mL); and butyrate was the main carboxylic acid by-product (~ 3 g/L). In P2 experiments after sludge heat treatment, the highest hydrogen yield (1.66 ± 0.07 mol H 2 /mol glucose) and caproic acid production (~ 2 g/L) were observed at 20 g O 2 /L of manipueira COD, when bovine rumen was the inoculum. The primary metabolic degradation products in all P2 experiments were ethanol, acetic, butyric, propionic and caproic acids. The finding of caproic acid detection indicated that the applied conditions in manipueira anaerobic degradation favored carbon chain elongation over methanogenesis.

The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

USDA-ARS?s Scientific Manuscript database

The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown during...

Empirical Modeling of ICMEs Using ACE/SWICS Ionic Distributions

NASA Astrophysics Data System (ADS)

Rivera, Y.; Landi, E.; Lepri, S. T.; Gilbert, J. A.

2017-12-01

Coronal Mass Ejections (CMEs) are some of the largest, most energetic events in the solar system releasing an immense amount of plasma and magnetic field into the Heliosphere. The Earth-bound plasma plays a large role in space weather, causing geomagnetic storms that can damage space and ground based instrumentation. As a CME is released, the plasma experiences heating, expansion and acceleration; however, the physical mechanism supplying the heating as it lifts out of the corona still remains uncertain. From previous work we know the ionic composition of solar ejecta undergoes a gradual transition to a state where ionization and recombination processes become ineffective rendering the ionic composition static along its trajectory. This property makes them a good indicator of thermal conditions in the corona, where the CME plasma likely receives most of its heating. We model this so-called `freeze-in' process in Earth-directed CMEs using an ionization code to empirically determine the electron temperature, density and bulk velocity. `Frozen-in' ions from an ensemble of independently modeled plasmas within the CME are added together to fit the full range of observational ionic abundances collected by ACE/SWICS during ICME events. The models derived using this method are used to estimate the CME energy budget to determine a heating rate used to compare with a variety of heating mechanisms that can sustain the required heating with a compatible timescale.

Spectral Retrieval of Latent Heating Profiles from TRMM PR Data: Comparison of Look-Up Tables

NASA Technical Reports Server (NTRS)

Shige, Shoichi; Takayabu, Yukari N.; Tao, Wei-Kuo; Johnson, Daniel E.; Shie, Chung-Lin

2003-01-01

The primary goal of the Tropical Rainfall Measuring Mission (TRMM) is to use the information about distributions of precipitation to determine the four dimensional (i.e., temporal and spatial) patterns of latent heating over the whole tropical region. The Spectral Latent Heating (SLH) algorithm has been developed to estimate latent heating profiles for the TRMM Precipitation Radar (PR) with a cloud- resolving model (CRM). The method uses CRM- generated heating profile look-up tables for the three rain types; convective, shallow stratiform, and anvil rain (deep stratiform with a melting level). For convective and shallow stratiform regions, the look-up table refers to the precipitation top height (PTH). For anvil region, on the other hand, the look- up table refers to the precipitation rate at the melting level instead of PTH. For global applications, it is necessary to examine the universality of the look-up table. In this paper, we compare the look-up tables produced from the numerical simulations of cloud ensembles forced with the Tropical Ocean Global Atmosphere (TOGA) Coupled Atmosphere-Ocean Response Experiment (COARE) data and the GARP Atlantic Tropical Experiment (GATE) data. There are some notable differences between the TOGA-COARE table and the GATE table, especially for the convective heating. First, there is larger number of deepest convective profiles in the TOGA-COARE table than in the GATE table, mainly due to the differences in SST. Second, shallow convective heating is stronger in the TOGA COARE table than in the GATE table. This might be attributable to the difference in the strength of the low-level inversions. Third, altitudes of convective heating maxima are larger in the TOGA COARE table than in the GATE table. Levels of convective heating maxima are located just below the melting level, because warm-rain processes are prevalent in tropical oceanic convective systems. Differences in levels of convective heating maxima probably reflect differences in melting layer heights. We are now extending our study to simulations of other field experiments (e.g. SCSMEX and ARM) in order to examine the universality of the look-up table. The impact of look-up tables on the retrieved latent heating profiles will also be assessed.

PID Controller Settings Based on a Transient Response Experiment

ERIC Educational Resources Information Center

Silva, Carlos M.; Lito, Patricia F.; Neves, Patricia S.; Da Silva, Francisco A.

2008-01-01

An experimental work on controller tuning for chemical engineering undergraduate students is proposed using a small heat exchange unit. Based upon process reaction curves in open-loop configuration, system gain and time constant are determined for first order model with time delay with excellent accuracy. Afterwards students calculate PID…

Not-from-concentrate blueberry juice extraction utilizing frozen fruit, heated mash, and enzyme processes

USDA-ARS?s Scientific Manuscript database

Juice production is a multibillion dollar industry and an economical way to use fruit past seasonal harvests. To evaluate how production steps influence not-from-concentrate (NFC) blueberry (Vaccinium sp.) juice recovery, bench top and pilot scale experiments were performed. In bench-top, southern h...

Energy--What to Do until the Computer Comes.

ERIC Educational Resources Information Center

Johnston, Archie B.

Drawing from Tallahassee Community College's (TCC's) experiences with energy conservation, this paper offers suggestions for reducing energy costs through computer-controlled systems and other means. After stating the energy problems caused by TCC's multi-zone heating and cooling system, the paper discusses the five-step process by which TCC…

DIY Soundcard Based Temperature Logging System. Part II: Applications

ERIC Educational Resources Information Center

Nunn, John

2016-01-01

This paper demonstrates some simple applications of how temperature logging systems may be used to monitor simple heat experiments, and how the data obtained can be analysed to get some additional insight into the physical processes. [For "DIY Soundcard Based Temperature Logging System. Part I: Design," see EJ1114124.

Studying Photosynthesis by Measuring Fluorescence

ERIC Educational Resources Information Center

Sanchez, Jose Francisco; Quiles, Maria Jose

2006-01-01

This paper describes an easy experiment to study the absorption and action spectrum of photosynthesis, as well as the inhibition by heat, high light intensity and the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the photosynthetic process. The method involves measuring the chlorophyll fluorescence emitted by intact…

Teaching Process Engineering Principles Using an Ice Cream Maker

ERIC Educational Resources Information Center

Kaletunc, Gonul; Duemmel, Kevin; Gecik, Christopher

2007-01-01

The ice cream laboratory experiment is designed to illustrate and promote discussion of several engineering and science topics including material and energy balances, heat transfer, freezing, mass transfer, mixing, viscosity, and freezing point depression in a sophomore level engineering class. A pre-lab assignment requires the students to develop…

Manufacture and quality control of interconnecting wire harnesses, Volume 3

NASA Technical Reports Server (NTRS)

1972-01-01

The document covers interconnecting wire harnesses defined in the design standard, including type 6, enclosed in TFE heat shrink tubing; and type 7, flexible armored. Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated into this document.

Helping Students Understand Challenging Topics in Science through Ontology Training

ERIC Educational Resources Information Center

Slotta, James D.; Chi, Michelene T. H.

2006-01-01

Chi (2005) proposed that students experience difficulty in learning about physics concepts such as light, heat, or electric current because they attribute to these concepts an inappropriate ontological status of material substances rather than the more veridical status of emergent processes. Conceptual change could thus be facilitated by training…

Learning by Brewing: Beer Production Experiments in the Chemical Engineering Laboratory

ERIC Educational Resources Information Center

Cerretani, Colin; Kelkile, Esayas; Landry, Alexandra

2017-01-01

We discuss the successful creation and implementation of a biotechnology track within the chemical engineering unit operations course. The track focuses on engineering principles relevant to brewing. Following laboratory modules investigating heat transfer processes and yeast fermentation kinetics, student groups design and implement a project to…

Modeling of thermal processes arising during shaping gears with internal non-involute teeth

NASA Astrophysics Data System (ADS)

Kanatnikov, N. V.; Kanatnikova, P. A.; Vlasov, V. V.; Pashmentova, A. S.

2018-03-01

The paper presents a model for predicting the thermal processes arising during shaping gears with internal non-involute teeth. The kinematics of cutting is modeled due to the analytical model. Chipping is modeled using the finite element method. The experiment is based on the method of infrared photography of the cutting process. The simulation results showed that the maximum temperatures and heat flows in the tool vary by more than 10% when the rake and clearance angels of the cutting are changed.

Electron Transport Modeling of Molecular Nanoscale Bridges Used in Energy Conversion Schemes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunietz, Barry D

2016-08-09

The goal of the research program is to reliably describe electron transport and transfer processes at the molecular level. Such insight is essential for improving molecular applications of solar and thermal energy conversion. We develop electronic structure models to study (1) photoinduced electron transfer and transport processes in organic semiconducting materials, and (2) charge and heat transport through molecular bridges. We seek fundamental understanding of key processes, which lead to design new experiments and ultimately to achieve systems with improved properties.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthew R. Kumjian; Giangrande, Scott E.; Mishra, Subashree

Polarimetric radar observations increasingly are used to understand cloud microphysical processes, which is critical for improving their representation in cloud and climate models. In particular, there has been recent focus on improving representations of ice collection processes (e.g., aggregation, riming), as these influence precipitation rate, heating profiles, and ultimately cloud life cycles. However, distinguishing these processes using conventional polarimetric radar observations is difficult, as they produce similar fingerprints. This necessitates improved analysis techniques and integration of complementary data sources. Furthermore, the Midlatitude Continental Convective Clouds Experiment (MC3E) provided such an opportunity.

Experimental investigation of heat transfer coefficient of mini-channel PCHE (printed circuit heat exchanger)

NASA Astrophysics Data System (ADS)

Kwon, Dohoon; Jin, Lingxue; Jung, WooSeok; Jeong, Sangkwon

2018-06-01

Heat transfer coefficient of a mini-channel printed circuit heat exchanger (PCHE) with counter-flow configuration is investigated. The PCHE used in the experiments is two layered (10 channels per layer) and has the hydraulic diameter of 1.83 mm. Experiments are conducted under various cryogenic heat transfer conditions: single-phase, boiling and condensation heat transfer. Heat transfer coefficients of each experiments are presented and compared with established correlations. In the case of the single-phase experiment, empiricial correlation of modified Dittus-Boelter correlation was proposed, which predicts the experimental results with 5% error at Reynolds number range from 8500 to 17,000. In the case of the boiling experiment, film boiling phenomenon occurred dominantly due to large temperature difference between the hot side and the cold side fluids. Empirical correlation is proposed which predicts experimental results with 20% error at Reynolds number range from 2100 to 2500. In the case of the condensation experiment, empirical correlation of modified Akers correlation was proposed, which predicts experimental results with 10% error at Reynolds number range from 3100 to 6200.

Localized Electrical Heating System for Various Types of Buildings

NASA Astrophysics Data System (ADS)

Shelehov, I. Y.; Smirnov, E. I.; Inozemsev, V. P.

2017-11-01

The article presents an overview of the factors determining the establishment of zones with high temperature in industrial, public and administrative buildings. The authors state the task on the improvement of the electric energy use efficiency and cost savings associated with the heating of these buildings by infrared electric heater devices. Materials and methods: The experiments were conducted in a room with the sizes of 3x6 m2 with a ceiling height of 3 m, the concrete floor was covered with laminate, in which increments of 250 mm were drilled and installed the thermocouple. In the process, had used the patented heating element with distributed heating layer. Signals from the thermocouples were recorded by instruments of the firm “ARIES” brand TPM138 with the standard software delivered together with devices (Owen Process Manager). The obtained distributions of the temperature fields were imported into MS Excel. Control voltage, current consumption, power was carried out by the device of firm “ARIES” brand of IMS. The results of the study: the article defines the purpose of the study and carried out the characterization of infrared heaters with various types of heating elements. The authors detail the main parameters of different types of infrared heaters, evaluated its possibility for application in other areas where the need to create areas of increased temperature. Discussion and conclusion: the result of this work it was determined that heating appliances that use patented heating element with distributed heating layer, improve thermal performance and bring you maximum comfort at a much greater distance compared to existing similar devices

Determination of the natural convection coefficient in low-gravity

NASA Technical Reports Server (NTRS)

Goldmeer, J.; Motevalli, V.; Haghdoust, M.; Jumper, G.

1992-01-01

Fire safety is an important issue in the current space program; ignition in low-g needs to be studied. The reduction in the gravitational acceleration causes changes in the ignition process. This paper examines the effect of gravity on natural convection, which is one of the important parameters in the ignition process. The NASA-Lewis 2.2 Second Drop Tower provided the low-gravity environment for the experiments. A series of experiments was conducted to measure the temperature of a small copper plate which was heated by a high intensity lamp. These experiments verified that in low-gravity the plate temperature increased faster than in the corresponding 1-g cases, and that the natural convection coefficient rapidly decreased in the low-gravity environment.

Methodology for the investigation of ignition near hot surfaces in a high-pressure shock tube

NASA Astrophysics Data System (ADS)

Niegemann, P.; Fikri, M.; Wlokas, I.; Röder, M.; Schulz, C.

2018-05-01

Autoignition of fuel/air mixtures is a determining process in internal combustion engines. Ignition can start either homogeneously in the gas phase after compression or in the vicinity of hot surfaces. While ignition properties of commercial fuels are conventionally described by a single quantity (octane number), it is known that some fuels have a varying propensity to the two processes. We present a new experimental concept that generates well-controlled temperature inhomogeneities in the shock-heated gases of a high-pressure shock tube. A shock-heated reactive mixture is brought into contact with a heated silicon nitride ceramic glow plug. The glow-plug temperature can be set up to 1200 K, higher than the post-reflected-shock gas temperatures (650-1050 K). High-repetition-rate chemiluminescence imaging is used to localize the onset of ignition in the vicinity of the hot surface. In experiments with ethanol, the results show that in most cases under shock-heated conditions, the ignition begins inhomogeneously in the vicinity of the glow plug and is favored because of the high wall temperature. Additionally, the interaction of geometry, external heating, and gas-dynamic effects was investigated by numerical simulations of the shock wave in a non-reactive flow.

Methodology for the investigation of ignition near hot surfaces in a high-pressure shock tube.

PubMed

Niegemann, P; Fikri, M; Wlokas, I; Röder, M; Schulz, C

2018-05-01

Autoignition of fuel/air mixtures is a determining process in internal combustion engines. Ignition can start either homogeneously in the gas phase after compression or in the vicinity of hot surfaces. While ignition properties of commercial fuels are conventionally described by a single quantity (octane number), it is known that some fuels have a varying propensity to the two processes. We present a new experimental concept that generates well-controlled temperature inhomogeneities in the shock-heated gases of a high-pressure shock tube. A shock-heated reactive mixture is brought into contact with a heated silicon nitride ceramic glow plug. The glow-plug temperature can be set up to 1200 K, higher than the post-reflected-shock gas temperatures (650-1050 K). High-repetition-rate chemiluminescence imaging is used to localize the onset of ignition in the vicinity of the hot surface. In experiments with ethanol, the results show that in most cases under shock-heated conditions, the ignition begins inhomogeneously in the vicinity of the glow plug and is favored because of the high wall temperature. Additionally, the interaction of geometry, external heating, and gas-dynamic effects was investigated by numerical simulations of the shock wave in a non-reactive flow.

Molecular Mechanisms Contributing to the Growth and Physiology of an Extremophile Cultured with Dielectric Heating.

PubMed

Cusick, Kathleen D; Lin, Baochuan; Malanoski, Anthony P; Strycharz-Glaven, Sarah M; Cockrell-Zugell, Allison; Fitzgerald, Lisa A; Cramer, Jeffrey A; Barlow, Daniel E; Boyd, Thomas J; Biffinger, Justin C

2016-10-15

The effect of microwave frequency electromagnetic fields on living microorganisms is an active and highly contested area of research. One of the major drawbacks to using mesophilic organisms to study microwave radiation effects is the unavoidable heating of the organism, which has limited the scale (<5 ml) and duration (<1 h) of experiments. However, the negative effects of heating a mesophile can be mitigated by employing thermophiles (organisms able to grow at temperatures of >60°C). This study identified changes in global gene expression profiles during the growth of Thermus scotoductus SA-01 at 65°C using dielectric (2.45 GHz, i.e., microwave) heating. RNA sequencing was performed on cultures at 8, 14, and 24 h after inoculation to determine the molecular mechanisms contributing to long-term cellular growth and survival under microwave heating conditions. Over the course of growth, genes associated with amino acid metabolism, carbohydrate metabolism, and defense mechanisms were upregulated; the number of repressed genes with unknown function increased; and at all time points, transposases were upregulated. Genes involved in cell wall biogenesis and elongation were also upregulated, consistent with the distinct elongated cell morphology observed after 24 h using microwave heating. Analysis of the global differential gene expression data enabled the identification of molecular processes specific to the response of T. scotoductus SA-01 to dielectric heating during growth. The residual heating of living organisms in the microwave region of the electromagnetic spectrum has complicated the identification of radiation-only effects using microorganisms for 50 years. A majority of the previous experiments used either mature cells or short exposure times with low-energy high-frequency radiation. Using global differential gene expression data, we identified molecular processes unique to dielectric heating using Thermus scotoductus SA-01 cultured over 30 h in a commercial microwave digestor. Genes associated with amino acid metabolism, carbohydrate metabolism, and defense mechanisms were upregulated; the number of repressed genes with unknown function increased; and at all time points, transposases were upregulated. These findings serve as a platform for future studies with mesophiles in order to better understand the response of microorganisms to microwave radiation. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe.

PubMed

Zhao, Shanguo; Xu, Guoying; Wang, Ning; Zhang, Xiaosong

2018-01-28

The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties-including the thermal conductivity and viscosity-of nanofluid with various graphene nanoplatelets (GNPs) concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe's start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected.

Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe

PubMed Central

Zhao, Shanguo; Xu, Guoying; Wang, Ning; Zhang, Xiaosong

2018-01-01

The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties—including the thermal conductivity and viscosity—of nanofluid with various graphene nanoplatelets (GNPs) concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe’s start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected. PMID:29382094

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leigh, Christi D.; Hansen, Francis D.

This report summarizes the state of salt repository science, reviews many of the technical issues pertaining to disposal of heat-generating nuclear waste in salt, and proposes several avenues for future science-based activities to further the technical basis for disposal in salt. There are extensive salt formations in the forty-eight contiguous states, and many of them may be worthy of consideration for nuclear waste disposal. The United States has extensive experience in salt repository sciences, including an operating facility for disposal of transuranic wastes. The scientific background for salt disposal including laboratory and field tests at ambient and elevated temperature, principlesmore » of salt behavior, potential for fracture damage and its mitigation, seal systems, chemical conditions, advanced modeling capabilities and near-future developments, performance assessment processes, and international collaboration are all discussed. The discussion of salt disposal issues is brought current, including a summary of recent international workshops dedicated to high-level waste disposal in salt. Lessons learned from Sandia National Laboratories' experience on the Waste Isolation Pilot Plant and the Yucca Mountain Project as well as related salt experience with the Strategic Petroleum Reserve are applied in this assessment. Disposal of heat-generating nuclear waste in a suitable salt formation is attractive because the material is essentially impermeable, self-sealing, and thermally conductive. Conditions are chemically beneficial, and a significant experience base exists in understanding this environment. Within the period of institutional control, overburden pressure will seal fractures and provide a repository setting that limits radionuclide movement. A salt repository could potentially achieve total containment, with no releases to the environment in undisturbed scenarios for as long as the region is geologically stable. Much of the experience gained from United States repository development, such as seal system design, coupled process simulation, and application of performance assessment methodology, helps define a clear strategy for a heat-generating nuclear waste repository in salt.« less

Computational modeling of the pressurization process in a NASP vehicle propellant tank experimental simulation

NASA Technical Reports Server (NTRS)

Sasmal, G. P.; Hochstein, J. I.; Wendl, M. C.; Hardy, T. L.

1991-01-01

A multidimensional computational model of the pressurization process in a slush hydrogen propellant storage tank was developed and its accuracy evaluated by comparison to experimental data measured for a 5 ft diameter spherical tank. The fluid mechanic, thermodynamic, and heat transfer processes within the ullage are represented by a finite-volume model. The model was shown to be in reasonable agreement with the experiment data. A parameter study was undertaken to examine the dependence of the pressurization process on initial ullage temperature distribution and pressurant mass flow rate. It is shown that for a given heat flux rate at the ullage boundary, the pressurization process is nearly independent of initial temperature distribution. Significant differences were identified between the ullage temperature and velocity fields predicted for pressurization of slush and those predicted for pressurization of liquid hydrogen. A simplified model of the pressurization process was constructed in search of a dimensionless characterization of the pressurization process. It is shown that the relationship derived from this simplified model collapses all of the pressure history data generated during this study into a single curve.

Thermal resistance of naturally occurring airborne bacterial spores. [Viking spacecraft dry heat decontamination simulation

NASA Technical Reports Server (NTRS)

Puleo, J. R.; Bergstrom, S. L.; Peeler, J. T.; Oxborrow, G. S.

1978-01-01

Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 C. The 30-h cycle differs from the 5- and 15-h cycles at 125 C. Thus, the heating cycle can be reduced if a small fraction (about 0.001 to 0.0001) of very resistant spores can be tolerated.

Did an Impact Make the Mysterious Microscopic Magnetite Crystals in ALH 84001?

NASA Astrophysics Data System (ADS)

Taylor, G. J.

2007-10-01

Fervent debate swirls around microscopic crystals of magnetite (Fe3O4) in Martian meteorite ALH 84001. Some investigators suggest that the crystals are evidence of past life on Mars, citing magnetite crystals of similar chemical compositions and sizes made by magnetotactic bacteria on Earth. Others cite assorted experiments and observations to argue that the important little crystals formed entirely by non-biological processes, hence say nothing about life on Mars. One of those processes is the decomposition of iron carbonate (the mineral siderite), which occurs in ALH 84001. Researchers argue that heating this mineral causes it to decompose into magnetite and CO2 gas. Experiments showing this were done by heating siderite and observing that it decomposed and formed magnetite, but nobody had shock-heated siderite to see if magnetite crystals formed. (Shock is a rapid, strong rise and fall in pressure. It happens under many circumstances, including meteorite impacts.) The lack of shock experiments has been solved by Mary Sue Bell (University of Houston and Jacobs Engineering). She experimentally shocked samples of siderite at the Experimental Impact Laboratory at the Johnson Space Center. She shows that magnetite crystals of the right size and composition formed when samples were shocked to 49 GPa (about 500,000 times the pressure at the Earth's surface). This is more evidence for a non-biological origin for the magnetite crystals in ALH 84001 and is consistent with what we know about the impact history of the rock. There seems to be growing evidence against a biological origin, but don't expect these results to completely settle the debate!

The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD

NASA Astrophysics Data System (ADS)

Thienel, Lee; Stouffer, Chuck

1995-09-01

This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.

The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD

NASA Technical Reports Server (NTRS)

Thienel, Lee; Stouffer, Chuck

1995-01-01

This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.

Supporting flight data analysis for Space Shuttle Orbiter Experiments at NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Green, M. J.; Budnick, M. P.; Yang, L.; Chiasson, M. P.

1983-01-01

The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.

Supporting flight data analysis for Space Shuttle Orbiter experiments at NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Green, M. J.; Budnick, M. P.; Yang, L.; Chiasson, M. P.

1983-01-01

The space shuttle orbiter experiments program is responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The infrared imagery of shuttle (IRIS), catalytic surface effects, and tile gap heating experiments sponsored by Ames Research Center are part of this program. The software required to process the flight data which support these experiments is described. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques provide information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third shuttle mission.

Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

NASA Astrophysics Data System (ADS)

Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao

2017-09-01

In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

Observations of the effect of wind on the cooling of active lava flows

USGS Publications Warehouse

Keszthelyi, L.; Harris, A.J.L.; Dehn, J.

2003-01-01

We present the first direct observations of the cooling of active lava flows by the wind. We confirm that atmospheric convective cooling processes (i.e., the wind) dominate heat loss over the lifetime of a typical pahochoe lava flow. In fact, the heat extracted by convection is greater than predicted, especially at wind speeds less than 5 m/s and surface temperatures less than 400??C. We currently estimate that the atmospheric heat transfer coefficient is about 45-50 W m-2 K-1 for a 10 m/s wind and a surface temperature ???500??C. Further field experiments and theoretical studies should expand these results to a broader range of surface temperatures and wind speeds.

Safety studies on vacuum insulated liquid helium cryostats

NASA Astrophysics Data System (ADS)

Weber, C.; Henriques, A.; Zoller, C.; Grohmann, S.

2017-12-01

The loss of insulating vacuum is often considered as a reasonable foreseeable accident for the dimensioning of cryogenic safety relief devices (SRD). The cryogenic safety test facility PICARD was designed at KIT to investigate such events. In the course of first experiments, discharge instabilities of the spring loaded safety relief valve (SRV) occurred, the so-called chattering and pumping effects. These instabilities reduce the relief flow capacity, which leads to impermissible over-pressures in the system. The analysis of the process dynamics showed first indications for a smaller heat flux than the commonly assumed 4W/cm2. This results in an oversized discharge area for the reduced relief flow rate, which corresponds to the lower heat flux. This paper presents further experimental investigations on the venting of the insulating vacuum with atmospheric air under variation of the set pressure (p set) of the SRV. Based on dynamic process analysis, the results are discussed with focus on effective heat fluxes and operating characteristics of the spring-loaded SRV.

The effects of maintaining temperature in annealing heat treatment for an FSWed 6061-T6 Al alloy.

PubMed

Lee, Seung-Jun; Han, Min-Su; Kim, Seong-Jong

2013-08-01

The technological development of all kinds of lightweight transportation devices including vehicles, aircraft, ships, etc. has progressed markedly with the demand for energy saving and environmental protection. Aluminum alloy is in the spotlight as it is a suitable environmentally friendly material. However, deformation is a major problem during the welding process because aluminum alloy has a large thermal expansion coefficient. In addition, it is known that its corrosion resistance is excellent; nevertheless, in practice, considerable corrosion is generated and this is a major problem. To solve this problem, the friction stir welding (FSW) technology is applied extensively at various industrial fields as a new welding technique. This method involves a process in which materials are joined by frictional heat and physical force. Therefore, we evaluated improvements in mechanical properties and corrosion resistance through annealing heat treatment after FSW. The electrochemical experiment did not show a significant difference. However, the microstructure observation showed defectless, fine crystal particles, indicating excellent properties at 200-225°C.

Drilling of optical glass with electroplated diamond tools

NASA Astrophysics Data System (ADS)

Wang, A. J.; Luan, C. G.; Yu, A. B.

2010-10-01

K9 optical glass drilling experiments were carried out. Bright nickel electroplated diamond tools with small slots and under heat treatment in different temperature were fabricated. Scan electro microscope was applied to analyze the wear of electroplated diamond tool. The material removal rate and grinding ratio were calculated. Machining quality was observed. Bond coating hardness was measured. The experimental results show that coolant is needed for the drilling processes of optical glasses. Heat treatment temperature of diamond tool has influence on wearability of diamond tool and grinding ratio. There were two wear types of electroplated diamond tool, diamond grit wear and bond wear. With the machining processes, wear of diamond grits included fracture, blunt and pull-out, and electroplated bond was gradually worn out. High material removal rates could be obtained by using diamond tool with suitable slot numbers. Bright nickel coating bond presents smallest grains and has better mechanical properties. Bright nickel electroplated diamond tool with slot structure and heat treatment under 200°C was suitable for optical glass drilling.

Effect of mixing during fermentation in yogurt manufacturing.

PubMed

Aguirre-Ezkauriatza, E J; Galarza-González, M G; Uribe-Bujanda, A I; Ríos-Licea, M; López-Pacheco, F; Hernández-Brenes, C M; Alvarez, M M

2008-12-01

In traditional yogurt manufacturing, the yogurt is not agitated during fermentation. However, stirring could be beneficial, particularly for improving heat and mass transport across the fermentation tank. In this contribution, we studied the effect of low-speed agitation during fermentation on process time, acidity profile, and microbial dynamics during yogurt fermentation in 2 laboratory-scale fermenters (3 and 5 L) with different heat-transfer characteristics. Lactobacillus bulgaricus and Streptococcus thermophilus were used as fermenting bacteria. Curves of pH, lactic acid concentration, lactose concentration, and bacterial population profiles during fermentation are presented for static and low-agitation conditions during fermentation. At low-inoculum conditions, agitation reduced the processing time by shortening the lag phase. However, mixing did not modify the duration or the shape of the pH profiles during the exponential phase. In fermentors with poor heat-transfer characteristics, important differences in microbial dynamics were observed between the agitated and nonagitated fermentation experiments; that is, agitation significantly increased the observable specific growth rate and the final microbial count of L. bulgaricus.

The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies

PubMed Central

Turchinovich, Dmitry; Kläui, Mathias; Hendry, Euan; Polini, Marco

2018-01-01

For many of the envisioned optoelectronic applications of graphene, it is crucial to understand the subpicosecond carrier dynamics immediately following photoexcitation and the effect of photoexcitation on the electrical conductivity—the photoconductivity. Whereas these topics have been studied using various ultrafast experiments and theoretical approaches, controversial and incomplete explanations concerning the sign of the photoconductivity, the occurrence and significance of the creation of additional electron-hole pairs, and, in particular, how the relevant processes depend on Fermi energy have been put forward. We present a unified and intuitive physical picture of the ultrafast carrier dynamics and the photoconductivity, combining optical pump–terahertz probe measurements on a gate-tunable graphene device, with numerical calculations using the Boltzmann equation. We distinguish two types of ultrafast photo-induced carrier heating processes: At low (equilibrium) Fermi energy (EF ≲ 0.1 eV for our experiments), broadening of the carrier distribution involves interband transitions (interband heating). At higher Fermi energy (EF ≳ 0.15 eV), broadening of the carrier distribution involves intraband transitions (intraband heating). Under certain conditions, additional electron-hole pairs can be created [carrier multiplication (CM)] for low EF, and hot carriers (hot-CM) for higher EF. The resultant photoconductivity is positive (negative) for low (high) EF, which in our physical picture, is explained using solely electronic effects: It follows from the effect of the heated carrier distributions on the screening of impurities, consistent with the DC conductivity being mostly due to impurity scattering. The importance of these insights is highlighted by a discussion of the implications for graphene photodetector applications. PMID:29756035

The Role of the Persian Gulf in Shaping Southwest Asian Surface Climate

NASA Astrophysics Data System (ADS)

Pal, J. S.; Eltahir, E. A. B.

2015-12-01

Summer surface climate of the Persian Gulf region is characterized by hot and humid conditions. Despite such conditions - which in other regions tends to trigger moist convection - typically this region experiences clear sky conditions and very little rainfall in the summer. In this study, we customize the MIT Regional Climate Model specifically for the Southwest Asia region and apply it at a 25-km grid spacing using reanalysis boundary conditions for present-day climate (1975-2005). Specific customizations include accurate representations of surface albedo and emissivity as well as mineral dust processes, all of which improve model bias. To assess the role of the Persian Gulf in shaping the region's climate, a 30-year experiment is performed without the Persian Gulf characterized. Results suggest that observed conditions over the Persian Gulf are due to a combination of physical processes involving adiabatic and diabatic descent. First, virtually clear sky conditions, due to subsidence during summer associated with the rising air motion over the monsoon region to the east, suppress upward motion and deep convection and increase incoming solar radiation. Second, the low surface albedo of the Persian Gulf results in enhanced absorption of solar radiation and total heat flux. Third, high evaporation rates increase water vapor, and therefore trap heat at the surface via the greenhouse effect for water vapor. Fourth, the relatively shallow boundary layer over the Persian Gulf concentrates water vapor and heat close to the surface. These combined factors maximize the total flux of heat in the boundary layer and hence moist static energy over the Persian Gulf.

On the meaning of peak temperature profiles in inverted metamorphic sequences

NASA Astrophysics Data System (ADS)

Duprat-Oualid, Sylvia; Yamato, Philippe

2017-07-01

Inverted metamorphic sequences (IMS) are common features of main thrust systems on Earth. They exhibit an upwards continuous increase in peak temperature conditions and thereby constitute evidence of the close relationship between the thermal field evolution and tectonic processes. Heat advection and shear heating are known to allow the formation of such metamorphic signatures. Heat diffusion also plays an important role in temperature distribution on both sides of the thrust. Other advection processes such as erosion or accretion may also cause a local peak temperature inversion. Each one of these processes therefore affects the thermal field around the thrust. However, despite the crucial importance of all these processes for the interpretation of the inverted peak temperature signatures, their respective influences have never been quantified and compared all together. To address this issue, we propose an innovative coupled approach. (i) We use two-dimensional numerical models that simulate various thrust systems, allowing for a wide diversity of setups. To illustrate this study, we focus on intracontinental thrust systems for which all processes listed are likely to play a key role in the thermal evolution. We perform a parametric study including kinematic settings (i.e. convergence, erosion and accretion), thermal properties, mechanical strength and heat sources. (ii) Dimensionless numbers based on parameters are used to quantify the relative contributions of each process to the thermal budget evolution. Hence, the three thermal processes (i.e. heat diffusion, heat advection and shear heating) are compared with each other via three dimensionless combinations of the Peclet and Brinkman numbers: RDif, RAdv and RPro, respectively. Erosion and accretion are compared separately, based on a fourth dimensionless number Rea. (iii) We analytically examine the inverted peak temperature recorded along profiles that are perpendicular to the thrust zone defined in our numerical experiments. Each peak temperature profile presenting an inversion can then be characterized by a function of approximation involving six meaningful parameters: the location μFF and width σFF of the maximum peak temperature inversion, the characteristic peak temperature Tcte and gradient GLB beneath the inversion zone, and the inversion-related contrasts in the peak temperature ΔT and gradient ΔG. This coupled approach, linking numerical modelling and analytical treatment, allows to quantitatively interpret IMS in terms of the processes involved. The application of our method to intracontinental thrust systems demonstrates that shear heating and erosion support significant inversions, but that the relative contributions of each process have meaningful consequences. Our results reveal that competition between shear heating and heat diffusion on the one hand, and between erosion and accretion on the other hand have a high impact. In particular, the variability in the rock's mechanical strength strongly influences the features of peak temperature inversions. Consequently, none of these processes can be ignored. Our results highlight the major importance of the rheology of rocks in the thermal evolution of shear zones. Finally, our methodology is not only restricted to the analysis of numerical data but also constitutes a way of broad interest to analyse peak temperature signatures around any shear zone.

Capillary Pumped Heat Transfer (CHT) Experiment

NASA Technical Reports Server (NTRS)

Hallinan, Kevin P.; Allen, J. S.

1998-01-01

The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

Calculation and experimental determination of the geometric parameters of the coatings by laser cladding

NASA Astrophysics Data System (ADS)

Birukov, V. P.; Fichkov, A. A.

2017-12-01

In the present work the experiments on laser cladding of powder Fe-B-Cr-6-2 on samples of steel 20. Metallographic studies of geometric parameters of deposited layers and the depth of the heat affected zone (HAZ). Using is the method of full factorial experiment (FFE) mathematical dependences of the geometrical sizes of the deposited layers of processing modes. Deviation of calculated values from experimental data is not more than 3%.

Future Experiments to Measure Liquid-Gas Phase Change and Heat Transfer Phenomena on the International Space Station

NASA Astrophysics Data System (ADS)

Tóth, Balázs; Development; Operations Teams, ESA's Science Management, Payload; Teams, Science; Industry, Space

2012-06-01

The article presents the approach of the European Space Agency to promote research in weightlessness and in particular onboard the International Space Station. In order to maximize the return on investments, a strong international scientific collaboration is encouraged. These Science Teams support the preparation and utilisation of the flight hardware and exploit the measurement data. In the domain of physical sciences the topics dealt with at the time of writing the present paper cover fundamental physics, fluid physics, material sciences research and specific preparatory studies in anticipation of space exploration missions. The present article focuses on two-phase (liquid-gas phase change) heat transfer related experiments. These activities cover evaporation driven thermocapillary convection, pool- and flow boiling, evaporation and condensation of films together with wettability realted issues on both reference and structured surfaces, and heat pipe systems. Some hardware are in an advanced state of development, the feasibility of some was studied or is under definition at the time of the preparation of this paper. The objectives of the experiments are described together with their expected capabilities. Beyond the understanding of mostly fundamental physical processes, the data of all the described experiments are intended to be used to validate theoretical approaches and numerical tools, which are often developed by the Science Teams in parallel with the the flight hardware design activities of space industry.

Characterization of simultaneous heat and mass transfer phenomena for water vapour condensation on a solid surface in an abiotic environment--application to bioprocesses.

PubMed

Tiwari, Akhilesh; Kondjoyan, Alain; Fontaine, Jean-Pierre

2012-07-01

The phenomenon of heat and mass transfer by condensation of water vapour from humid air involves several key concepts in aerobic bioreactors. The high performance of bioreactors results from optimised interactions between biological processes and multiphase heat and mass transfer. Indeed in various processes such as submerged fermenters and solid-state fermenters, gas/liquid transfer need to be well controlled, as it is involved at the microorganism interface and for the control of the global process. For the theoretical prediction of such phenomena, mathematical models require heat and mass transfer coefficients. To date, very few data have been validated concerning mass transfer coefficients from humid air inflows relevant to those bioprocesses. Our study focussed on the condensation process of water vapour and developed an experimental set-up and protocol to study the velocity profiles and the mass flux on a small size horizontal flat plate in controlled environmental conditions. A closed circuit wind tunnel facility was used to control the temperature, hygrometry and hydrodynamics of the flow. The temperature of the active surface was controlled and kept isothermal below the dew point to induce condensation, by the use of thermoelectricity. The experiments were performed at ambient temperature for a relative humidity between 35-65% and for a velocity of 1.0 ms⁻¹. The obtained data are analysed and compared to available theoretical calculations on condensation mass flux.

Prediction of temperature and HAZ in thermal-based processes with Gaussian heat source by a hybrid GA-ANN model

NASA Astrophysics Data System (ADS)

Fazli Shahri, Hamid Reza; Mahdavinejad, Ramezanali

2018-02-01

Thermal-based processes with Gaussian heat source often produce excessive temperature which can impose thermally-affected layers in specimens. Therefore, the temperature distribution and Heat Affected Zone (HAZ) of materials are two critical factors which are influenced by different process parameters. Measurement of the HAZ thickness and temperature distribution within the processes are not only difficult but also expensive. This research aims at finding a valuable knowledge on these factors by prediction of the process through a novel combinatory model. In this study, an integrated Artificial Neural Network (ANN) and genetic algorithm (GA) was used to predict the HAZ and temperature distribution of the specimens. To end this, a series of full factorial design of experiments were conducted by applying a Gaussian heat flux on Ti-6Al-4 V at first, then the temperature of the specimen was measured by Infrared thermography. The HAZ width of each sample was investigated through measuring the microhardness. Secondly, the experimental data was used to create a GA-ANN model. The efficiency of GA in design and optimization of the architecture of ANN was investigated. The GA was used to determine the optimal number of neurons in hidden layer, learning rate and momentum coefficient of both output and hidden layers of ANN. Finally, the reliability of models was assessed according to the experimental results and statistical indicators. The results demonstrated that the combinatory model predicted the HAZ and temperature more effective than a trial-and-error ANN model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsytovich, Vadim, E-mail: tsytov@lpi.ru; Max Planck Institute for Extraterrestrial Physics, Garching; Gusein-zade, Namik

Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, themore » total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere.« less

Sensitivity Analysis and Optimization of Enclosure Radiation with Applications to Crystal Growth

NASA Technical Reports Server (NTRS)

Tiller, Michael M.

1995-01-01

In engineering, simulation software is often used as a convenient means for carrying out experiments to evaluate physical systems. The benefit of using simulations as 'numerical' experiments is that the experimental conditions can be easily modified and repeated at much lower cost than the comparable physical experiment. The goal of these experiments is to 'improve' the process or result of the experiment. In most cases, the computational experiments employ the same trial and error approach as their physical counterparts. When using this approach for complex systems, the cause and effect relationship of the system may never be fully understood and efficient strategies for improvement never utilized. However, it is possible when running simulations to accurately and efficiently determine the sensitivity of the system results with respect to simulation to accurately and efficiently determine the sensitivity of the system results with respect to simulation parameters (e.g., initial conditions, boundary conditions, and material properties) by manipulating the underlying computations. This results in a better understanding of the system dynamics and gives us efficient means to improve processing conditions. We begin by discussing the steps involved in performing simulations. Then we consider how sensitivity information about simulation results can be obtained and ways this information may be used to improve the process or result of the experiment. Next, we discuss optimization and the efficient algorithms which use sensitivity information. We draw on all this information to propose a generalized approach for integrating simulation and optimization, with an emphasis on software programming issues. After discussing our approach to simulation and optimization we consider an application involving crystal growth. This application is interesting because it includes radiative heat transfer. We discuss the computation of radiative new factors and the impact this mode of heat transfer has on our approach. Finally, we will demonstrate the results of our optimization.

Proportional integral derivative, modeling and ways of stabilization for the spark plasma sintering process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manière, Charles; Lee, Geuntak; Olevsky, Eugene A.

The stability of the proportional–integral–derivative (PID) control of temperature in the spark plasma sintering (SPS) process is investigated. The PID regulations of this process are tested for different SPS tooling dimensions, physical parameters conditions, and areas of temperature control. It is shown that the PID regulation quality strongly depends on the heating time lag between the area of heat generation and the area of the temperature control. Tooling temperature rate maps are studied to reveal potential areas for highly efficient PID control. The convergence of the model and experiment indicates that even with non-optimal initial PID coefficients, it is possiblemore » to reduce the temperature regulation inaccuracy to less than 4 K by positioning the temperature control location in highly responsive areas revealed by the finite-element calculations of the temperature spatial distribution.« less

Aeration control of thermophilic aerobic digestion using fluorescence monitoring.

PubMed

Kim, Young-Kee; Oh, Byung-Keun

2009-01-01

The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate.

Chill Down Process of Hydrogen Transport Pipelines

NASA Technical Reports Server (NTRS)

Mei, Renwei; Klausner, James

2006-01-01

A pseudo-steady model has been developed to predict the chilldown history of pipe wall temperature in the horizontal transport pipeline for cryogenic fluids. A new film boiling heat transfer model is developed by incorporating the stratified flow structure for cryogenic chilldown. A modified nucleate boiling heat transfer correlation for cryogenic chilldown process inside a horizontal pipe is proposed. The efficacy of the correlations is assessed by comparing the model predictions with measured values of wall temperature in several azimuthal positions in a well controlled experiment by Chung et al. (2004). The computed pipe wall temperature histories match well with the measured results. The present model captures important features of thermal interaction between the pipe wall and the cryogenic fluid, provides a simple and robust platform for predicting pipe wall chilldown history in long horizontal pipe at relatively low computational cost, and builds a foundation to incorporate the two-phase hydrodynamic interaction in the chilldown process.

Proportional integral derivative, modeling and ways of stabilization for the spark plasma sintering process

DOE PAGES

Manière, Charles; Lee, Geuntak; Olevsky, Eugene A.

2017-04-21

The stability of the proportional–integral–derivative (PID) control of temperature in the spark plasma sintering (SPS) process is investigated. The PID regulations of this process are tested for different SPS tooling dimensions, physical parameters conditions, and areas of temperature control. It is shown that the PID regulation quality strongly depends on the heating time lag between the area of heat generation and the area of the temperature control. Tooling temperature rate maps are studied to reveal potential areas for highly efficient PID control. The convergence of the model and experiment indicates that even with non-optimal initial PID coefficients, it is possiblemore » to reduce the temperature regulation inaccuracy to less than 4 K by positioning the temperature control location in highly responsive areas revealed by the finite-element calculations of the temperature spatial distribution.« less

Improved silicon carbide for advanced heat engines. I - Process development for injection molding

NASA Technical Reports Server (NTRS)

Whalen, Thomas J.; Trela, Walter

1989-01-01

Alternate processing methods have been investigated as a means of improving the mechanical properties of injection-molded SiC. Various mixing processes (dry, high-sheer, and fluid) were evaluated along with the morphology and particle size of the starting beta-SiC powder. Statistically-designed experiments were used to determine significant effects and interactions of variables in the mixing, injection molding, and binder removal process steps. Improvements in mechanical strength can be correlated with the reduction in flaw size observed in the injection molded green bodies obtained with improved processing methods.

Application of functionalized nanofluid in thermosyphon

PubMed Central

2011-01-01

A water-based functionalized nanofluid was made by surface functionalizing the ordinary silica nanoparticles. The functionalized nanofluid can keep long-term stability. and no sedimentation was observed. The functionalized nanofluid as the working fluid is applied in a thermosyphon to understand the effect of this special nanofluid on the thermal performance of the thermosyphon. The experiment was carried out under steady operating pressures. The same work was also explored for traditional nanofluid (consisting of water and the same silica nanoparticles without functionalization) for comparison. Results indicate that a porous deposition layer exists on the heated surface of the evaporator during the operating process using traditional nanofluid; however, no coating layer exists for functionalized nanofluid. Functionalized nanofluid can enhance the evaporating heat transfer coefficient, while it has generally no effect on the maximum heat flux. Traditional nanofluid deteriorates the evaporating heat transfer coefficient but enhances the maximum heat flux. The existence of the deposition layer affects mainly the thermal performance, and no meaningful nanofluid effect is found in the present study. PMID:21846362

AMTEC powered residential furnace and auxiliary power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanenok, J.F. III; Sievers, R.K.

1996-12-31

Residential gas furnaces normally rely on utility grid electric power to operate the fans and/or the pumps used to circulate conditioned air or water and they are thus vulnerable to interruptions of utility grid service. Experience has shown that such interruptions can occur during the heating season, and can lead to serious consequences. A gas furnace coupled to an AMTEC conversion system retains the potential to produce heat and electricity (gas lines are seldom interrupted during power outages), and can save approximately $47/heating season compared to a conventional gas furnace. The key to designing a power system is understanding, andmore » predicting, the cell performance characteristics. The three main processes that must be understood and modeled to fully characterize an AMTEC cell are the electro-chemical, sodium vapor flow, and heat transfer. This paper will show the results of the most recent attempt to model the heat transfer in a multi-tube AMTEC cell and then discusses the conceptual design of a self-powered residential furnace.« less

Analytical determination of the heat transfer coefficient for gas, liquid and liquid metal flows in the tube based on stochastic equations and equivalence of measures for continuum

NASA Astrophysics Data System (ADS)

Dmitrenko, Artur V.

2017-11-01

The stochastic equations of continuum are used for determining the heat transfer coefficients. As a result, the formulas for Nusselt (Nu) number dependent on the turbulence intensity and scale instead of only on the Reynolds (Peclet) number are proposed for the classic flows of a nonisothermal fluid in a round smooth tube. It is shown that the new expressions for the classical heat transfer coefficient Nu, which depend only on the Reynolds number, should be obtained from these new general formulas if to use the well-known experimental data for the initial turbulence. It is found that the limitations of classical empirical and semiempirical formulas for heat transfer coefficients and their deviation from the experimental data depend on different parameters of initial fluctuations in the flow for different experiments in a wide range of Reynolds or Peclet numbers. Based on these new dependences, it is possible to explain that the differences between the experimental results for the fixed Reynolds or Peclet numbers are caused by the difference in values of flow fluctuations for each experiment instead of only due to the systematic error in the experiment processing. Accordingly, the obtained general dependences of Nu for a smooth round tube can serve as the basis for clarifying the experimental results and empirical formulas used for continuum flows in various power devices. Obtained results show that both for isothermal and for nonisothermal flows, the reason for the process of transition from a deterministic state into a turbulent one is determined by the physical law of equivalence of measures between them. Also the theory of stochastic equations and the law of equivalence of measures could determine mechanics which is basis in different phenomena of self-organization and chaos theory.

In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

NASA Technical Reports Server (NTRS)

Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

1990-01-01

Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

Fluid physics, thermodynamics, and heat transfer experiments in space

NASA Technical Reports Server (NTRS)

Dodge, F. T.; Abramson, H. N.; Angrist, S. W.; Catton, I.; Churchill, S. W.; Mannheimer, R. J.; Otrach, S.; Schwartz, S. H.; Sengers, J. V.

1975-01-01

An overstudy committee was formed to study and recommend fundamental experiments in fluid physics, thermodynamics, and heat transfer for experimentation in orbit, using the space shuttle system and a space laboratory. The space environment, particularly the low-gravity condition, is an indispensable requirement for all the recommended experiments. The experiments fell broadly into five groups: critical-point thermophysical phenomena, fluid surface dynamics and capillarity, convection at reduced gravity, non-heated multiphase mixtures, and multiphase heat transfer. The Committee attempted to assess the effects of g-jitter and other perturbations of the gravitational field on the conduct of the experiments. A series of ground-based experiments are recommended to define some of the phenomena and to develop reliable instrumentation.

Experience gained in France on heat recovery from nuclear plants for agriculture and pisciculture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balligand, P.; Le Gouellec, P.; Dumont, M.

1978-04-01

Since 1972, the Commissariat a l'Energie Atomique, Electricite de France, and the French Ministry of Agriculture have jointly examined the possibility of using thermal wastes from nuclear power plants for the benefit of agricultural production. A new process to heat greenhouses with water at 303 K using a double-wall plastic mulching laid directly on the soil has been successfully used for a few years on several hectares. When necessary, heat pumps are utilized. Very good results have been obtained for tomatoes, cucumbers, flowers, and strawberries, etc. Outdoor soil heating with buried pipes has been tested in Cadarache near an experimentalmore » pressurized water reactor for market garden crops and forestry. Gains in precocity and yield have been excellent, especially for asparagus, strawberries, and potatoes. Growing of eels has been four times faster in warm water over one year.« less

Molecular dynamics simulations of aggregation of copper nanoparticles with different heating rates

NASA Astrophysics Data System (ADS)

Li, Qibin; Wang, Meng; Liang, Yunpei; Lin, Liyang; Fu, Tao; Wei, Peitang; Peng, Tiefeng

2017-06-01

Molecular dynamics simulations were employed to investigate the heating rates' effect on aggregation of two copper nanoparticles. The aggregation can be distinguished into three distinct regimes by the contacting and melting of nanoparticles. The nanoparticles contacting at a lower temperature during the sintering with lower heating rate, meanwhile, some temporary stacking fault exists at the contacting neck. The aggregation properties of the system, i.e. neck diameter, shrinkage ratio, potential energy, mean square displacement (MSD) and relative gyration radius, experience drastic changes due to the free surface annihilation. After the nanoparticles coalesced for a stable period, the shrinkage ratio, MSD, relative gyration radius and neck diameter of the system are dramatically changed during the melting process. It is shown that the shrinkage ratio and MSD have relative larger increasing ratio for a lower heating rate. While the evolution of the relative gyration radius and neck diameter is only sensitive to the temperature.

Method and apparatus for studying high-temperature properties of conductive materials in the interests of nuclear power engineering

NASA Astrophysics Data System (ADS)

Savvatimskiy, A. I.; Onufriev, S. V.

2016-12-01

Physical processes during a rapid (microsecond) heating of metals, carbon, and their compounds by a single pulse of electric current are discussed. Effects arising in such short-term heating near the melting point are noted: the electron emission and heat capacity anomalies and the possible occurrence of Frenkel pair (interstitial atom and vacancy). The problem of measuring the temperature using optical methods under pulse heating is considered, including the use of a specimen in the form of a blackbody model. The melting temperature of carbon (4800-4900 K) is measured at increased pulse pressure. The results of studying the properties of metals (by example of zirconium and hafnium) and of zirconium carbide at high temperatures are discussed. The schematics of the pulse setups and the instrumentation, as well as specimens for a pulse experiment, are presented.

Toward a new < 250 °C pyrrhotite-magnetite geothermometer for claystones

NASA Astrophysics Data System (ADS)

Aubourg, Charles; Pozzi, Jean-Pierre

2010-05-01

We investigate the effects of burial and moderate experimental heating on claystones from three regions with different degrees of maturation: immature (burial temperature ˜ 40 °C) of Bure Callovo-Oxfordian claystones in the Basin of Paris (France); early mature (burial temperature ˜ 85 °C) of Opalinus Lower Dogger claystones from the Mont Terri anticline in front of the Jura fold belt (Switzerland); and mature to overmature (burial temperature < 170 °C) of Chartreuse Callovian-Oxfordian claystones from Chartreuse Sub-Alpine chains. To have information about the nature of the magnetic assemblage, we perform low-temperature (10 K-300 K) investigation of an isothermal remanent magnetization. In a first set of laboratory heating experiments, we aim to impart a chemical remanent magnetization (CRM) at 95 °C for several weeks in Bure and Opalinus claystones. Thermal demagnetization of the CRM reveals that magnetite is formed by heating the Opalinus claystones while an assemblage of magnetite and iron sulphide is formed in Bure claystones. Further, we document the appearance of a magnetic transition at ˜ 35 K in Bure claystones after heating. We name this transition the P-transition and we propose that it is related to the formation of fine-grained pyrrhotite (Fe 7S 8). The P-transition is also detected in early mature to mature Opalinus and Chartreuse claystones. We conduct additional experimental heating of natural Opalinus claystones. One set of experiments is referred to as short-term heating (1 h) from 100 °C to 200 °C. It is dedicated to an investigation of the effect of short-lived heating processes in geology. A second set of heating experiments is designed to approach burial conditions using a gold capsule. In burial-like experiments, we heated Opalinus claystones from 150 °C to 250 °C for several weeks under a pressure of 100 MPa. In both experiments, we observe a correlative diminution of the pyrrhotite signature at 35 K with increasing temperature. We interpret this trend as the appearance of magnetite. We derive a parameter PM from the warming curve of a saturated isothermal remanent magnetization acquired at 10 K (ZFC). We report on a consistent evolution of PM with temperature in the range of 40 °C to 250 °C, including natural samples, heated samples at 95 °C, and burial-like heated samples. PM first increases between ˜ 40 °C up to ˜ 85 °C, implying that pyrrhotite gradually dominates the magnetic assemblage at low temperature. For temperatures above 85 °C, PM decreases up to 250 °C, implying that the formation of magnetite gradually overshadows the magnetic input of pyrrhotite. PM values obtained from mature to overmature claystones from the Chartreuse are lower than the PM values obtained from the burial-like heated Opalinus claystones, suggesting that the formation of magnetite is driven by kinetics. The continuous trend of the PM parameter suggests that the magnetic properties of pyrrhotite-magnetite claystones can be used to infer paleo-temperatures and we propose to name this geothermometer MagEval.

Shock recovery analogs and the origin of mesosiderites. [Abstract only

NASA Technical Reports Server (NTRS)

Rowan, L. R.

1994-01-01

The origin of mesosiderites, which consist of approximately equal-weight proportions of Fe-Ni metal and silicates (gabbros, basalts, orthopyroxenites, dunites), remains an interesting and complex problem in meteoritics. There is general agreement that multiple impact events were probably involved in the formation of these brecciated stony-iron meteorites, but given the heterogeneity of mesosiderites, additional processes have been invoked to explain the unique and intricate textural and compositional makeup of mesosiderites. We conducted a series of shock recovery experiments to test the impact event(s) scenario. The results indicated significant similarities between the shocked analogs and many mesosiderites. We have compared our analogs with a suite of thin sections of Barea mesosiderite. I have conducted a series of flash heating experiments in which equal-weight proportions of gabbro and stainless steel (SS304) powders were compressed into small charges and heated under reducing conditions for short times. These experiments were used to bracket localized, peak postshock temperatures in our analog shots and to compare the mixing relations between the silicate and metal. The shock recovery experiments used porous metal-silicate powder starting mixtures, therefore our experiments are most analogous to an impact scenario where the target is an asteroidal regolith surface composed of a loose mixture of Fe-Ni metal and heterogeneous silicates. Analog experiments may really describe a secondary impact process similar to the late-stage, localized impact melting event. This leaves one of the crucial questions about mesosiderite genesis unanswered, namely what is the source of the Fe-Ni metal that is so intimately distributed in these meteorites?

Automated Fiber Placement of PEEK/IM7 Composites with Film Interleaf Layers

NASA Technical Reports Server (NTRS)

Hulcher, A. Bruce; Banks, William I., III; Pipes, R. Byron; Tiwari, Surendra N.; Cano, Roberto J.; Johnston, Norman J.; Clinton, R. G., Jr. (Technical Monitor)

2001-01-01

The incorporation of thin discrete layers of resin between plies (interleafing) has been shown to improve fatigue and impact properties of structural composite materials. Furthermore, interleafing could be used to increase the barrier properties of composites used as structural materials for cryogenic propellant storage. In this work, robotic heated-head tape placement of PEEK/IM7 composites containing a PEEK polymer film interleaf was investigated. These experiments were carried out at the NASA Langley Research Center automated fiber placement facility. Using the robotic equipment, an optimal fabrication process was developed for the composite without the interleaf. Preliminary interleaf processing trials indicated that a two-stage process was necessary; the film had to be tacked to the partially-placed laminate then fully melted in a separate operation. Screening experiments determined the relative influence of the various robotic process variables on the peel strength of the film-composite interface. Optimization studies were performed in which peel specimens were fabricated at various compaction loads and roller temperatures at each of three film melt processing rates. The resulting data were fitted with quadratic response surfaces. Additional specimens were fabricated at placement parameters predicted by the response surface models to yield high peel strength in an attempt to gage the accuracy of the predicted response and assess the repeatability of the process. The overall results indicate that quality PEEK/lM7 laminates having film interleaves can be successfully and repeatability fabricated by heated head automated fiber placement.

Hydraulic characterization of aquifers by thermal response testing

NASA Astrophysics Data System (ADS)

Wagner, Valentin; Blum, Philipp; Bayer, Peter

2014-05-01

Temperature as a major physical quantity of the subsurface, and naturally occurring thermal anomalies are recognized as promising passive tracers to characterize the subsurface. Accelerated by the increasing popularity of geothermal energy, also active thermal field experiments have gained interest in hydrogeology. Such experiments involve artificial local ground heating or cooling. Among these, the thermal response test (TRT) is one of the most established field investigation techniques in shallow geothermal applications. It is a common method to investigate important subsurface heat transport parameters to design sustainable ground-source heat pump (GSHP) systems. During the test, the borehole heat exchanger (BHE) is heated up with a defined amount of energy by circulating a heat carrier fluid. By comparing temperature change between BHE inlet and outlet, the ability of the BHE to transfer heat or cold to the ambient ground is assessed. However, standard interpretation does not provide any insight into the governing processes of in-situ heat transfer. We utilize a groundwater advection sensitive TRT evaluation approach based on the analytical moving line source equation. It is shown that the TRT as a classical geothermal field test can also be used as a hydrogeological field test. Our approach benefits from the fact that thermal properties, such as thermal conductivity, of natural aquifers typically are much less variable than hydraulic properties, such as hydraulic conductivity. It is possible to determine a relatively small hydraulic conductivity range with our TRT evaluation approach, given realistic ranges for thermal conductivity, volumetric heat capacity, thermal dispersivity and thermal borehole resistance. The method is successfully tested on a large-scale geothermal laboratory experiment (9 m × 6 m × 4.5 m) and with a commercially performed TRT in the field scale. The laboratory experiment consists of a layered artificial aquifer, which is penetrated by a short BHE. This BHE is used to record a groundwater influenced TRT dataset. The performed field TRT is measured at a BHE located in the Upper Rhine Valley in South-West Germany, which penetrates a 68 m thick gravel aquifer with significant horizontal groundwater flow. At both sites, the derived hydraulic conductivity ranges obtained from TRT evaluation are shown to be within the ranges obtained from classical hydrogeological methods such as sieve analysis and pumping tests. This confirms that the temperature signal recorded during thermal response tests can be employed as a thermal tracer and that the evaluation of such a signal can be applied to estimate aquifer hydraulic conductivities.

Experimental study on pool boiling of distilled water and HFE7500 fluid under microgravity

NASA Astrophysics Data System (ADS)

Yang, Yan-jie; Chen, Xiao-qian; Huang, Yi-yong; Li, Guang-yu

2018-02-01

The experimental study on bubble behavior and heat transfer of pool boiling for distilled water and HFE7500 fluid under microgravity has been conducted by using drop tower in the National Microgravity Laboratory of China (NMLC). Two MCH ceramic plates of 20 mm(L) × 10 mm(W) × 1.2 mm(H) were used as the heaters. The nucleate boiling evolution under microgravity was observed during the experiment. It has been found that at the same heat flux, the bubbles of HFE7500 (which has smaller contact angle) grew faster and bigger, moved quickly on the heater surface, and were easier to merge into a central big bubble with other bubbles than that of distilled water. The whole process of bubbles coalescence from seven to one was recorded by using video camera. For distilled water (with bigger contact angle), the bubbles tended to keep at the nucleate location on heater surface, and the central big bubble evolved at its nucleate cite by absorbing smaller bubbles nearby. Compared with the bubbles under normal gravity, bubble radius of distilled water under microgravity was about 1.4 times bigger and of HFE7500 was about more than 6 times bigger till the end of experiment. At the beginning, pool boiling heat transfer of distilled water was advanced and then impeded under microgravity. As to HFE7500, the pool boiling impedes the heat transfer from heater to liquid under microgravity throughout the experiment.

A high density field reversed configuration (FRC) target for magnetized target fusion: First internal profile measurements of a high density FRC

NASA Astrophysics Data System (ADS)

Intrator, T.; Zhang, S. Y.; Degnan, J. H.; Furno, I.; Grabowski, C.; Hsu, S. C.; Ruden, E. L.; Sanchez, P. G.; Taccetti, J. M.; Tuszewski, M.; Waganaar, W. J.; Wurden, G. A.

2004-05-01

Magnetized target fusion (MTF) is a potentially low cost path to fusion, intermediate in plasma regime between magnetic and inertial fusion energy. It requires compression of a magnetized target plasma and consequent heating to fusion relevant conditions inside a converging flux conserver. To demonstrate the physics basis for MTF, a field reversed configuration (FRC) target plasma has been chosen that will ultimately be compressed within an imploding metal liner. The required FRC will need large density, and this regime is being explored by the FRX-L (FRC-Liner) experiment. All theta pinch formed FRCs have some shock heating during formation, but FRX-L depends further on large ohmic heating from magnetic flux annihilation to heat the high density (2-5×1022m-3), plasma to a temperature of Te+Ti≈500 eV. At the field null, anomalous resistivity is typically invoked to characterize the resistive like flux dissipation process. The first resistivity estimate for a high density collisional FRC is shown here. The flux dissipation process is both a key issue for MTF and an important underlying physics question.

Remote enzyme activation using gold coated magnetite as antennae for radio frequency fields

NASA Astrophysics Data System (ADS)

Collins, Christian B.; Ackerson, Christopher J.

2018-02-01

The emerging field of remote enzyme activation, or the ability to remotely turn thermophilic increase enzyme activity, could be a valuable tool for understanding cellular processes. Through exploitation of the temperature dependence of enzymatic processes and high thermal stability of thermophilic enzymes these experiments utilize nanoparticles as `antennae' that convert radiofrequency (RF) radiation into local heat, increasing activity of the enzymes without increasing the temperature of the surrounding bulk solution. To investigate this possible tool, thermolysin, a metalloprotease was covalently conjugated to 4nm gold coated magnetite particles via peptide bond formation with the protecting ligand shell. RF stimulated protease activity at 17.76 MHz in a solenoid shaped antenna, utilizing both electric and magnetic field interactions was investigated. On average 40 percent higher protease activity was observed in the radio frequency fields then when bulk heating the sample to the same temperature. This is attributed to electrophoretic motion of the nanoparticle enzyme conjugates and local regions of heat generated by the relaxation of the magnetite cores with the oscillating field. Radio frequency local heating of nanoparticles conjugated to enzymes as demonstrated could be useful in the activation of specific enzymes in complex cellular environments.

A full 3D model of fluid flow and heat transfer in an E.B. heated liquid metal bath

NASA Astrophysics Data System (ADS)

Matveichev, A.; Jardy, A.; Bellot, J. P.

2016-07-01

In order to study the dissolution of exogeneous inclusions in the liquid metal during processing of titanium alloys, a series of dipping experiments has been performed in an Electron Beam Melting laboratory furnace. Precise determination of the dissolution kinetics requires knowing and mastering the exact thermohydrodynamic behavior of the melt pool, which implies full 3D modeling of the process. To achieve this goal, one needs to describe momentum and heat transfer, phase change, as well as the development of flow turbulence in the liquid. EB power input, thermal radiation, heat loss through the cooling circuit, surface tension effects (i.e. Marangoni-induced flow) must also be addressed in the model. Therefore a new solver dealing with all these phenomena was implemented within OpenFOAM platform. Numerical results were compared with experimental data from actual Ti melting, showing a pretty good agreement. In the second stage, the immersion of a refractory sample rod in the liquid pool was simulated. Results of the simulations showed that the introduction of the sample slightly disturbs the flow field inside the bath. The amount of such disturbance depends on the exact location of the dipping.

Proposal of experimental setup on boiling two-phase flow on-orbit experiments onboard Japanese experiment module "KIBO"

NASA Astrophysics Data System (ADS)

Baba, S.; Sakai, T.; Sawada, K.; Kubota, C.; Wada, Y.; Shinmoto, Y.; Ohta, H.; Asano, H.; Kawanami, O.; Suzuki, K.; Imai, R.; Kawasaki, H.; Fujii, K.; Takayanagi, M.; Yoda, S.

2011-12-01

Boiling is one of the efficient modes of heat transfer due to phase change, and is regarded as promising means to be applied for the thermal management systems handling a large amount of waste heat under high heat flux. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. The experiments onboard Japanese Experiment Module "KIBO" in International Space Station on boiling two-phase flow under microgravity conditions are proposed to clarify both of heat transfer and flow characteristics under microgravity conditions. To verify the feasibility of ISS experiments on boiling two-phase flow, the Bread Board Model is assembled and its performance and the function of components installed in a test loop are examined.

Cutaway line drawing of STS-34 middeck experiment Polymer Morphology (PM)

NASA Technical Reports Server (NTRS)

1989-01-01

Cutaway line drawing shows components of STS-34 middeck experiment Polymer Morphology (PM). Generic Electronics Module (GEM) components include the control housing, circulating fans, hard disk, tape drives, computer boards, and heat exchanger. PM, a 3M-developed organic materials processing experiment, is designed to explore the effects of microgravity on polymeric materials as they are processed in space. The samples of polymeric materials being studied in the PM experiment are thin films (25 microns or less) approximately 25mm in diameter. The samples are mounted between two infrared transparent windows in a specially designed infrared cell that provides the capability of thermally processing the samples to 200 degrees Celsius with a high degree of thermal control. The samples are mounted on a carousel that allows them to be positioned, one at a time, in the infrared beam where spectra may be acquired. The GEM provides all carousel and sample cell control (SCC). The first flight of P

Experimental and Computational Investigations of Phase Change Thermal Energy Storage Canisters

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Kerslake, Thomas; Sokolov, Pavel; Tolbert, Carol

1996-01-01

Two sets of experimental data are examined in this paper, ground and space experiments, for cylindrical canisters with thermal energy storage applications. A 2-D computational model was developed for unsteady heat transfer (conduction and radiation) with phase-change. The radiation heat transfer employed a finite volume method. The following was found in this study: (1) Ground Experiments: the convection heat transfer is equally important to that of the radiation heat transfer; radiation heat transfer in the liquid is found to be more significant than that in the void; including the radiation heat transfer in the liquid resulted in lower temperatures (about 15 K) and increased the melting time (about 10 min.); generally, most of the heat flow takes place in the radial direction. (2) Space Experiments: radiation heat transfer in the void is found to be more significant than that in the liquid (exactly the opposite to the Ground Experiments); accordingly, the location and size of the void affects the performance considerably; including the radiation heat transfer in the void resulted in lower temperatures (about 40 K).

An Improved Heat Budget Estimation Including Bottom Effects for General Ocean Circulation Models

NASA Technical Reports Server (NTRS)

Carder, Kendall; Warrior, Hari; Otis, Daniel; Chen, R. F.

2001-01-01

This paper studies the effects of the underwater light field on heat-budget calculations of general ocean circulation models for shallow waters. The presence of a bottom significantly alters the estimated heat budget in shallow waters, which affects the corresponding thermal stratification and hence modifies the circulation. Based on the data collected during the COBOP field experiment near the Bahamas, we have used a one-dimensional turbulence closure model to show the influence of the bottom reflection and absorption on the sea surface temperature field. The water depth has an almost one-to-one correlation with the temperature rise. Effects of varying the bottom albedo by replacing the sea grass bed with a coral sand bottom, also has an appreciable effect on the heat budget of the shallow regions. We believe that the differences in the heat budget for the shallow areas will have an influence on the local circulation processes and especially on the evaporative and long-wave heat losses for these areas. The ultimate effects on humidity and cloudiness of the region are expected to be significant as well.

Thermal Excitation System for Shearography (TESS)

NASA Technical Reports Server (NTRS)

Lansing, Matthew D.; Bullock, Michael W.

1996-01-01

One of the most convenient and effective methods of stressing a part or structure for shearographic evaluation is thermal excitation. This technique involves heating the part, often convectively with a heat gun, and then monitoring with a shearography device the deformation during cooling. For a composite specimen, unbonds, delaminations, inclusions, or matrix cracking will deform during cooling differently than other more structurally sound regions and thus will appear as anomalies in the deformation field. However, one of the difficulties that cause this inspection to be dependent on the operator experience is the conventional heating process. Fanning the part with a heat gun by hand introduces a wide range of variability from person to person and from one inspection to the next. The goal of this research effort was to conduct research in the methods of thermal excitation for shearography inspection. A computerized heating system was developed for inspection of 0.61 m (24 in.) square panels. The Thermal Excitation System for Shearography (TESS) provides radiant heating with continuous digital measurement of the surface temperature profile to ensure repeatability. The TESS device functions as an accessory to any electronic shearography device.

Thermal processing differentially affects lycopene and other carotenoids in cis-lycopene containing, tangerine tomatoes.

PubMed

Cooperstone, Jessica L; Francis, David M; Schwartz, Steven J

2016-11-01

Tangerine tomatoes, unlike red tomatoes, accumulate cis-lycopenes instead of the all-trans isomer. cis-Lycopene is the predominating isomeric form of lycopene found in blood and tissues. Our objective was to understand how thermal processing and lipid concentration affect carotenoid isomerisation and degradation in tangerine tomatoes. We conducted duplicated factorial designed experiments producing tangerine tomato juice and sauce, varying both processing time and lipid concentration. Carotenoids were extracted and analysed using high-performance liquid chromatography with photodiode array detection. Phytoene, phytofluene, ζ-carotene, neurosporene, tetra-cis-lycopene, all-trans-lycopene and other-cis-lycopenes were quantified. Tetra-cis-lycopene decreased with increasing heating time and reached 80% of the original level in sauce after processing times of 180min. All-trans-lycopene and other-cis-lycopenes increased with longer processing times. Total carotenoids and total lycopene decreased with increased heating times while phytoene and phytofluene were unchanged. These data suggest limiting thermal processing of tangerine tomato products if delivery of tetra-cis-lycopene is desirable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Implementation of New System for Oxygen Generation and Carbon Dioxide Removal =

NASA Astrophysics Data System (ADS)

Karavolos, Angelo Peter

This research effort develops an integrated system for CO2 removal and O2 production. A unique material, dodeca-tungsto-phosphoric acid (H3PO4W12O3; henceforth referred to as DTPA) is mixed with tetra-ethyl-ortho-silicate Si(OC2H 5)4 or TEOS. This mixture exhibits unique properties of heat absorption and high electrical conductivity. In the system described herein, the DTPA resides within a cross linked arrangement of TEOS. The DTPA furnishes a source of O2, while the TEOS furnishes structural support for the large DTPA crystals. In addition, the large amount of H2O within the crystal also adsorbs CO2. It can also be cross-linked with other polymers such as polycarbonate, for different applications and properties such as flexible textiles. A set of isolated bench experiments were designed to test CO2 adsorption, O2 production, heat production, and voltage production were conducted to test the hypothesis that DTPA can provide CO2 adsorption, O2 generation, heat generation and electrical generation. Five experiments with this apparatus were conducted: (1) a mass balance experiment; (2) an X-ray diffraction experiment; (3) a photo spectroscopic experiment; (4) a calorimetric experiment; and (5) a dielectric experiment. Results illustrate that approximately 2880 grams of this material produces 576 grams of O2, and removes 1760 grams of CO2. The reaction also produces approximately 844 kJ/mole heat, and can supply 12.2 V potential over a period of 4.5 hours. The amount of unused material and the recycling ability suggests the usefulness of the technique to achieve between a 50-75% closed system. In addition, an experiment using 18O tracer demonstrated that approximately 20% of the O2 produced comes from processed CO2 adsorbed by the crystal, while the remaining 80% of the O2 produced comes from replaced O2 within the crystal itself. The device has multiple applications including environmental control and life support for aircraft cabins, space vehicle interiors, submarine pressure vessels, sealed armored vehicles, and personal protective equipment for individuals working in confined spaces such as mines. None

Residual Stress Analysis in Welded Component.

NASA Astrophysics Data System (ADS)

Rouhi, Shahab; Yoshida, Sanichiro; Miura, Fumiya; Sasaki, Tomohiro

Due to local heating, thermal stresses occur during welding; and residual stress and distortion result remain welding. Welding distortion has negative effects on the accuracy of assembly, exterior appearance, and various strengths of the welded structures. Up to date, a lot of experiments and numerical analysis have been developed to assess residual stress. However, quantitative estimation of residual stress based on experiment may involve massive uncertainties and complexity of the measurement process. To comprehensively understand this phenomena, it is necessary to do further researches by means of both experiment and numerical simulation. In this research, we conduct Finite Element Analysis (FEA) for a simple butt-welded metal plate specimen. Thermal input and resultant expansion are modeled with a thermal expansion FEA module and the resultant constitutive response of the material is modeled with a continuous mechanic FEA module. The residual stress is modeled based on permanent deformation occurring during the heating phase of the material. Experiments have also been carried out to compare with the FEA results. Numerical and experimental results show qualitative agreement. The present work was supported by the Louisiana Board of Regents (LEQSF(2016-17)-RD-C-13).

ICRF mode conversion in three-ion species heating experiment and in flow drive experiment on the Alcator C-Mod tokamak

NASA Astrophysics Data System (ADS)

Lin, Y.; Wukitch, S. J.; Edlund, E.; Ennever, P.; Hubbard, A. E.; Porkolab, M.; Rice, J.; Wright, J.

2017-10-01

In recent three-ion species (majority D and H plus a trace level of 3He) ICRF heating experiments on Alcator C-Mod, double mode conversion on both sides of the 3He cyclotron resonance has been observed using the phase contrast imaging (PCI) system. The MC locations are used to estimate the species concentrations in the plasma. Simulation using TORIC shows that with the 3He level <1%, most RF power is absorbed by the 3He ions and the process can generate energetic 3He ions. In mode conversion (MC) flow drive experiment in D(3He) plasma at 8 T, MC waves were also monitored by PCI. The MC ion cyclotron wave (ICW) amplitude and wavenumber kR have been found to correlate with the flow drive force. The MC efficiency, wave-number k of the MC ICW and their dependence on plasma parameters like Te0 have been studied. Based on the experimental observation and numerical study of the dispersion solutions, a hypothesis of the flow drive mechanism has been proposed.

The Law of Entropy Increase--A Lab Experiment

ERIC Educational Resources Information Center

Dittrich, William; Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

2016-01-01

The second law of thermodynamics has various formulations. There is the "Clausius formulation," which can be stated in a very intuitive way: "No process is possible whose sole result is the transfer of heat from a cooler to a hotter body." There is also the "Kelvin-Plank principle," which states that "no cyclic…

A Pilot-Scale Heat Recovery System for Computer Process Control Teaching and Research.

ERIC Educational Resources Information Center

Callaghan, P. J.; And Others

1988-01-01

Describes the experimental system and equipment including an interface box for displaying variables. Discusses features which make the circuit suitable for teaching and research in computing. Feedforward, decoupling, and adaptive control, examination of digital filtering, and a cascade loop are teaching experiments utilizing this rig. Diagrams and…

Relevance of Tidal Heating on Large TNOs

NASA Technical Reports Server (NTRS)

Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry A.

2017-01-01

We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100 s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

Relevance of tidal heating on large TNOs

NASA Astrophysics Data System (ADS)

Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry

2018-03-01

We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100‧s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

Experimental Study and Analytical Methods for Particle Bed Dryout With Heterogeneous Particles and Pressure Variation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miettinen, Jaakko; Sairanen, Risto; Lindholm, Ilona

2002-07-01

The interest to study the dryout heat flux in particle beds is related to interest of quantify the debris coolability margins during a hypothetical severe reactor accident. When the molten core has relocated to the containment floor, one accident management concept is based on the cooling of the corium by the water injection on top. Earlier experimental and analytical work has concentrated on homogeneous particle beds at atmospheric pressures. For plant safety assessment in Finland, there is a need to consider heterogeneous particle mixtures, layered particle bed setups and varied pressures. A facility has been constructed at VTT to measuremore » dryout heat flux in a heterogeneous particle bed. The bed dimensions are 0.3 m in diameter and 0.6 m in height, with a mixture of 0.1 to 10 mm particles. The facility has a pressure range from atmospheric to 6 bar (overpressure). The bed is heated by spirals of a resistance band. The preliminary experiments have been carried out, but a more systematic set of data is expected to be available in the spring 2002. To support the experiments analytical models have been developed for qualification of the experimental results. The first comparison is done against various critical heat flux correlations developed in 1980's and 1990's for homogeneous bed conditions. The second comparison is done against 1-D and 0-D models developed by Lipinski. The most detailed analysis of the transient process conditions and dryout predictions are done by using the two-dimensional, drift-flux based thermohydraulic solution for the particle bed immersed into the water. The code is called PILEXP. Already the first validation results against the preliminary tests indicate that the transient process conditions and the mechanisms related to the dryout can be best explained and understood by using a multidimensional, transient code, where all details of the process control can be modeled as well. The heterogeneous bed and stratified bed can not be well considered by single critical heat flux correlations. (authors)« less

CVB: the Constrained Vapor Bubble Capillary Experiment on the International Space Station MARANGONI FLOW REGION

NASA Technical Reports Server (NTRS)

Wayner, Peter C., Jr.; Kundan, Akshay; Plawsky, Joel

2014-01-01

The Constrained Vapor Bubble (CVB) is a wickless, grooved heat pipe and we report on a full- scale fluids experiment flown on the International Space Station (ISS). The CVB system consists of a relatively simple setup a quartz cuvette with sharp corners partially filled with either pentane or an ideal mixture of pentane and isohexane as the working fluids. Along with temperature and pressure measurements, the two-dimensional thickness profile of the menisci formed at the corners of the quartz cuvette was determined using the Light Microscopy Module (LMM). Even with the large, millimeter dimensions of the CVB, interfacial forces dominate in these exceedingly small Bond Number systems. The experiments were carried out at various power inputs. Although conceptually simple, the transport processes were found to be very complex with many different regions. At the heated end of the CVB, due to a high temperature gradient, we observed Marangoni flow at some power inputs. This region from the heated end to the central drop region is defined as a Marangoni dominated region. We present a simple analysis based on interfacial phenomena using only measurements from the ISS experiments that lead to a predictive equation for the thickness of the film near the heated end of the CVB. The average pressure gradient for flow in the film is assumed due to the measured capillary pressure at the two ends of the liquid film and that the pressure stress gradient due to cohesion self adjusts to a constant value over a distance L. The boundary conditions are the no slip condition at the wall interface and an interfacial shear stress at the liquid- vapor interface due to the Marangoni stress, which is due to the high temperature gradient. Although the heated end is extremely complex, since it includes three- dimensional variations in radiation, conduction, evaporation, condensation, fluid flow and interfacial forces, we find that using the above simplifying assumptions, a simple successful model can be developed.

Dependence of core heating properties on heating pulse duration and intensity

NASA Astrophysics Data System (ADS)

Johzaki, Tomoyuki; Nagatomo, Hideo; Sunahara, Atsushi; Cai, Hongbo; Sakagami, Hitoshi; Mima, Kunioki

2009-11-01

In the cone-guiding fast ignition, an imploded core is heated by the energy transport of fast electrons generated by the ultra-intense short-pulse laser at the cone inner surface. The fast core heating (˜800eV) has been demonstrated at integrated experiments with GEKKO-XII+ PW laser systems. As the next step, experiments using more powerful heating laser, FIREX, have been started at ILE, Osaka university. In FIREX-I (phase-I of FIREX), our goal is the demonstration of efficient core heating (Ti ˜ 5keV) using a newly developed 10kJ LFEX laser. In the first integrated experiments, the LFEX laser is operated with low energy mode (˜0.5kJ/4ps) to validate the previous GEKKO+PW experiments. Between the two experiments, though the laser energy is similar (˜0.5kJ), the duration is different; ˜0.5ps in the PW laser and ˜ 4ps in the LFEX laser. In this paper, we evaluate the dependence of core heating properties on the heating pulse duration on the basis of integrated simulations with FI^3 (Fast Ignition Integrated Interconnecting) code system.

Ion and electron heating characteristics of magnetic reconnection in tokamak plasma merging experiments

NASA Astrophysics Data System (ADS)

Ono, Y.; Tanabe, H.; Yamada, T.; Inomoto, M.; T, Ii; Inoue, S.; Gi, K.; Watanabe, T.; Gryaznevich, M.; Scannell, R.; Michael, C.; Cheng, C. Z.

2012-12-01

Recently, the TS-3 and TS-4 tokamak merging experiments revealed significant plasma heating during magnetic reconnection. A key question is how and where ions and electrons are heated during magnetic reconnection. Two-dimensional measurements of ion and electron temperatures and plasma flow made clear that electrons are heated inside the current sheet mainly by the Ohmic heating and ions are heated in the downstream areas mainly by the reconnection outflows. The outflow kinetic energy is thermalized by the fast shock formation and viscous damping. The magnetic reconnection converts the reconnecting magnetic field energy mostly to the ion thermal energy in the outflow region whose size is much larger than the current sheet size for electron heating. The ion heating energy is proportional to the square of the reconnection magnetic field component B_p^2 . This scaling of reconnection heating indicates the significant ion heating effect of magnetic reconnection, which leads to a new high-field reconnection heating experiment for fusion plasmas.

Heat extraction from salinity-gradient solar ponds using heat pipe heat exchangers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tundee, Sura; Terdtoon, Pradit; Sakulchangsatjatai, Phrut

This paper presents the results of experimental and theoretical analysis on the heat extraction process from solar pond by using the heat pipe heat exchanger. In order to conduct research work, a small scale experimental solar pond with an area of 7.0 m{sup 2} and a depth of 1.5 m was built at Khon Kaen in North-Eastern Thailand (16 27'N102 E). Heat was successfully extracted from the lower convective zone (LCZ) of the solar pond by using a heat pipe heat exchanger made from 60 copper tubes with 21 mm inside diameter and 22 mm outside diameter. The length ofmore » the evaporator and condenser section was 800 mm and 200 mm respectively. R134a was used as the heat transfer fluid in the experiment. The theoretical model was formulated for the solar pond heat extraction on the basis of the energy conservation equations and by using the solar radiation data for the above location. Numerical methods were used to solve the modeling equations. In the analysis, the performance of heat exchanger is investigated by varying the velocity of inlet air used to extract heat from the condenser end of the heat pipe heat exchanger (HPHE). Air velocity was found to have a significant influence on the effectiveness of heat pipe heat exchanger. In the present investigation, there was an increase in effectiveness by 43% as the air velocity was decreased from 5 m/s to 1 m/s. The results obtained from the theoretical model showed good agreement with the experimental data. (author)« less

Assessing heat treatment of chicken breast cuts by impedance spectroscopy.

PubMed

Schmidt, Franciny C; Fuentes, Ana; Masot, Rafael; Alcañiz, Miguel; Laurindo, João B; Barat, José M

2017-03-01

The aim of this work was to develop a new system based on impedance spectroscopy to assess the heat treatment of previously cooked chicken meat by two experiments; in the first, samples were cooked at different temperatures (from 60 to 90 ℃) until core temperature of the meat reached the water bath temperature. In the second approach, temperature was 80 ℃ and the samples were cooked for different times (from 5 to 55 min). Impedance was measured once samples had cooled. The examined processing parameters were the maximum temperature reached in thermal centre of the samples, weight loss, moisture and the integral of the temperature profile during the cooking-cooling process. The correlation between the processing parameters and impedance was studied by partial least square regressions. The models were able to predict the studied parameters. Our results are essential for developing a new system to control the technological, sensory and safety aspects of cooked meat products on the whole meat processing line.

Status and future trends of radiation processing in Brazil

NASA Astrophysics Data System (ADS)

Lugão, A. B.; Andrade, E.; Silva, L. G.

1998-06-01

Electron-beam and gamma irradiation of polymers are widely applied in Brazil today. The main applications are: - radio-induced crosslinking of wire and cable for automobile and appliance industry; - heat shrinkable tubes for appliance, automobile and electronic; - heat shrinkable packing for food processing industry; - sterilization of medical supplies and so on. Nevertheless, there are only a few industrial facilities about 20 years old in full operation at present and there are some new low energy machines for food packing. The reason for such absence of investment in this area was studied and the relation between automobile and appliance production with radiation processing was fully demonstrated for Brazil case. In conclusion, it was shown that the industry of radiation processing of polymers is likely to experience a strong growth based on the continuous increase in the production of automobiles and appliances. The R&D activities of IPEN are an important support for developing the necessary technology and developing the necessary confidence in the radiation as tool for economical and social growth.

On the limitations of General Circulation Climate Models

NASA Technical Reports Server (NTRS)

Stone, Peter H.; Risbey, James S.

1990-01-01

General Circulation Models (GCMs) by definition calculate large-scale dynamical and thermodynamical processes and their associated feedbacks from first principles. This aspect of GCMs is widely believed to give them an advantage in simulating global scale climate changes as compared to simpler models which do not calculate the large-scale processes from first principles. However, it is pointed out that the meridional transports of heat simulated GCMs used in climate change experiments differ from observational analyses and from other GCMs by as much as a factor of two. It is also demonstrated that GCM simulations of the large scale transports of heat are sensitive to the (uncertain) subgrid scale parameterizations. This leads to the question whether current GCMs are in fact superior to simpler models for simulating temperature changes associated with global scale climate change.

The interactive role of subsynoptic scale jet streak and planetary boundary layer processes in organizing an isolated convective complex

NASA Technical Reports Server (NTRS)

Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Coats, G. D.

1984-01-01

Surface analyses and numerical simulation sensitivity studies are compared in order to determine the role played by deep, well-mixed, and well-heated boundary layers in perturbing a weak jet streak in proximity to the development of an isolated but intense convective complex associated with the Grand Island, Nebraska tornado outbreak of June 3-4, 1980. A brief description of the case is first presented, emphasizing three-hourly surface analyses, radar, and satellite data. The results of numerical experiments comparing differences in the runs with and without diurnal surface sensible heating are discussed and related to observations. The dynamical processes responsible for these simulation differences are discussed, and the significance of these differences are considered in terms of their effect on the preconvective environment.

Experimental and numerical investigation of a scalable modular geothermal heat storage system

NASA Astrophysics Data System (ADS)

Nordbeck, Johannes; Bauer, Sebastian; Beyer, Christof

2017-04-01

Storage of heat will play a significant role in the transition towards a reliable and renewable power supply, as it offers a way to store energy from fluctuating and weather dependent energy sources like solar or wind power and thus better meet consumer demands. The focus of this study is the simulation-based design of a heat storage system, featuring a scalable and modular setup that can be integrated with new as well as existing buildings. For this, the system can be either installed in a cellar or directly in the ground. Heat supply is by solar collectors, and heat storage is intended at temperatures up to about 90°C, which requires a verification of the methods used for numerical simulation of such systems. One module of the heat storage system consists of a helical heat exchanger in a fully water saturated, high porosity cement matrix, which represents the heat storage medium. A lab-scale storage prototype of 1 m3 volume was set up in a thermally insulated cylinder equipped with temperature and moisture sensors as well as flux meters and temperature sensors at the inlet and outlet pipes in order to experimentally analyze the performance of the storage system. Furthermore, the experimental data was used to validate an accurate and spatially detailed high-resolution 3D numerical model of heat and fluid flow, which was developed for system design optimization with respect to storage efficiency and environmental impacts. Three experiments conducted so far are reported and analyzed in this work. The first experiment, consisting of cooling of the fully loaded heat storage by heat loss across the insulation, is designed to determine the heat loss and the insulation parameters, i.e. heat conductivity and heat capacity of the insulation, via inverse modelling of the cooling period. The average cooling rate experimentally found is 1.2 °C per day. The second experiment consisted of six days of thermal loading up to a storage temperature of 60°C followed by four days of heat extraction. The experiment was performed for the determination of heat losses during a complete thermal loading and extraction cycle. The storage could be charged with 54 kWh of heat energy during thermal loading. 36 kWh could be regained during the extraction period, which translates to a heat loss of 33% during the 10 days of operation. Heat exchanger fluid flow rates and supply temperature were measured during the experiment and used as input for the 3D finite element model. Numerically simulated temperature distribution in the storage, return temperature and heat balances were compared to the measured data and showed that the 3D model accurately reflects the storage behavior. Also the third experiment, consisting of six days of cyclic operation after five days of continuous thermal loading, a good agreement between observed and modelled heat storage behavior is found. In addition to determining the storage performance during cyclic operation, the experiment will also be used to further validate the numerical model. This abstract will present the laboratory setup as well as the experimental data obtained from the experiment. It will also present the modelling approach chosen for the numerical representation of the experiment and give a comparison between measured and modelled temperatures and heat balances for the modular heat storage system.

Evaluate the urban effect on summer convective precipitation by coupling a urban canopy model with a Regional Climate Model

NASA Astrophysics Data System (ADS)

Liu, Z.; Liu, S.; Xue, Y.; Oleson, K. W.

2013-12-01

One of the most significant urbanization in the world occurred in Great Beijing Area of China during the past several decades. The land use and land cover changes modifies the land surface physical characteristics, including the anthropogenic heat and thermo-dynamic conduction. All of those play important roles in the urban regional climate changes. We developed a single layer urban canopy module based on the Community Land Surface Model Urban Module (CLMU). We have made further improvements in the urban module: the energy balances on the five surface conditions are considered separately: building roof, sun side and shade side wall, pervious and impervious land surface. Over each surface, a method to calculate sky view factor (SVF) is developed based on the physically process while most urban models simply provide an empirical value; A new scheme for calculating the latent heat flux is applied on both wall and impervious land; anthropogenic heat is considered in terms of industrial production, domestic wastes, vehicle and air condition. All of these developments improve the accuracy of surface energy balance processing in urban area. The urban effect on summer convective precipitation under the unstable atmospheric condition in the Great Beijing Area was investigated by simulating a heavy rainfall event in July 21st 2012. In this storm, strong meso-scale convective complexes (MCC) brought precipitation of averagely 164 mm within 6 hours, which is the record of past 60 years in the region. Numerical simulating experiment was set up by coupling MCLMU with WRF. Several condition/blank control cases were also set up. The horizontal resolution in all simulations was 2 km. While all of the control results drastically underestimate the urban precipitation, the result of WRF-MCLMU is much closer to the observation though still underestimated. More sensitive experiments gave a preliminary conclusion of how the urban canopy physics processing affects the local precipitation: the existence of large area of impervious surfaces restrain the surface evaporation and latent heat flux in urban while the anthropogenic heat and enhanced sensible heat flux warm up the lower atmospheric layer and strengthen the vertical stratification instability; In this storm event, the water supply of the MCC was thought to be sufficient, thus the instability of the vertical stratification was the key factor for precipitation.

Optical absorption in recycled waste plastic polyethylene

NASA Astrophysics Data System (ADS)

Aji, M. P.; Rahmawati, I.; Priyanto, A.; Karunawan, J.; Wati, A. L.; Aryani, N. P.; Susanto; Wibowo, E.; Sulhadi

2018-03-01

We investigated the optical properties of UV spectrum absorption in recycled waste plastic from polyethylene polymer type. Waste plastic polyethylene showed an optical spectrum absorption after it’s recycling process. Spectrum absorption is determined using spectrophotometer UV-Nir Ocean Optics type USB 4000. Recycling method has been processed using heating treatment around the melting point temperature of the polyethylene polymer that are 200°C, 220°C, 240°C, 260°C, and 280°C. In addition, the recycling process was carried out with time variations as well, which are 1h, 1.5h, 2h, and 2.5h. The result of this experiment shows that recycled waste plastic polyethylene has a spectrum absorption in the ∼ 340-550 nm wavelength range. The absorbance spectrum obtained from UV light which is absorbed in the orbital n → π* and the orbital π → π*. This process indicates the existence of electron transition phenomena. This mechanism is affected by the temperature and the heating time where the intensity of absorption increases and widens with the increase of temperature and heating time. Furthermore this study resulted that the higher temperature affected the enhancement of the band gap energy of waste plastic polyethylene. These results show that recycled waste plastic polyethylene has a huge potential to be absorber materials for solar cell.

Experiments Towards Mitigation of Motional Heating in Trapped Ion Quantum Information Processing

DTIC Science & Technology

2016-02-27

in our surface electrode trap chips. The distance-dependence measurement was taken by Deslauri- ers et al . using a 3D needle trap [9]. These results...heating rate fit for this data is shown in Figure 6-5. 68 Delay time (ms) A ve ra ge M o ti o n al O cc u p at io n al L ev el ( ) <n...Wineland. Cooling in traps. Physica Scripta, 22:216–223, 1988 . [18] W. Itano and D. Wineland. Laser cooling of ions stored in harmonic and penning traps

Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

NASA Technical Reports Server (NTRS)

Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

1973-01-01

From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

Screening of liquids for thermocapillary bubble movement

NASA Technical Reports Server (NTRS)

Wilcox, W. R.; Subramanian, R. S.; Papazian, J. M.; Smith, H. D.; Mattox, D. M.

1979-01-01

Ground-based methods for pretesting qualitatively the thermocapillary movement of gas bubbles in a liquid to be used in space processing are discussed. Theoretical considerations are shown to require the use of a thin, enclosed, horizontal liquid film in order that the bubbles move faster than the bulk convection of the liquid, with insulating boundaries to prevent the onset of instabilities. Experimental realizations of horizontal cells in which to test the thermocapillary movement of bubbles in sheets of molten glass heated from below and organic melts in tubes heated from both ends are briefly described and the results of experiments are indicated.

Local feedback mechanisms of the shallow water region around the Maritime Continent

NASA Astrophysics Data System (ADS)

Xue, Pengfei; Eltahir, Elfatih A. B.; Malanotte-Rizzoli, Paola; Wei, Jun

2014-10-01

The focus of this study is the local-scale air-sea feedback mechanisms over the shallow shelf water region (water depth <200 m) of the Maritime Continent (MC). MC was selected as a pilot study site for its extensive shallow water coverage, geographic complexity, and importance in the global climate system. To identify the local-scale air-sea feedback processes, we ran numerical experiments with perturbed surface layer water temperature using a coupled ocean-atmosphere model and an uncoupled ocean model. By examining the responses of the coupled and uncoupled models to the water temperature perturbation, we identify that, at a local-scale, a negative feedback process through the coupled dynamics that tends to restore the SST from its perturbation could dominate the shallow water region of the MC at a short time scale of several days. The energy budget shows that 38% of initial perturbation-induced heat energy was adjusted through the air-sea feedback mechanisms within 2 weeks, of which 58% is directly transferred into the atmosphere by the adjustment of latent heat flux due to the evaporative cooling mechanism. The increased inputs of heat and moisture into the lower atmosphere then modifies its thermal structure and increases the formation of low-level clouds, which act as a shield preventing incoming solar radiation from reaching the sea surface, accounts for 38% of the total adjustment of surface heat fluxes, serving as the second mechanism for the negative feedback process. The adjustment of sensible heat flux and net longwave radiation play a secondary role. The response of the coupled system to the SST perturbation suggests a response time scale of the coupled feedback process of about 3-5 days. The two-way air-sea feedback tightly links the surface heat fluxes, clouds and SST, and can play an important role in regulating the short-term variability of the SST over the shallow shelf water regions.

Some relevant parameters for assessing fire hazards of combustible mine materials using laboratory scale experiments

PubMed Central

Litton, Charles D.; Perera, Inoka E.; Harteis, Samuel P.; Teacoach, Kara A.; DeRosa, Maria I.; Thomas, Richard A.; Smith, Alex C.

2018-01-01

When combustible materials ignite and burn, the potential for fire growth and flame spread represents an obvious hazard, but during these processes of ignition and flaming, other life hazards present themselves and should be included to ensure an effective overall analysis of the relevant fire hazards. In particular, the gases and smoke produced both during the smoldering stages of fires leading to ignition and during the advanced flaming stages of a developing fire serve to contaminate the surrounding atmosphere, potentially producing elevated levels of toxicity and high levels of smoke obscuration that render the environment untenable. In underground mines, these hazards may be exacerbated by the existing forced ventilation that can carry the gases and smoke to locations far-removed from the fire location. Clearly, materials that require high temperatures (above 1400 K) and that exhibit low mass loss during thermal decomposition, or that require high heat fluxes or heat transfer rates to ignite represent less of a hazard than materials that decompose at low temperatures or ignite at low levels of heat flux. In order to define and quantify some possible parameters that can be used to assess these hazards, small-scale laboratory experiments were conducted in a number of configurations to measure: 1) the toxic gases and smoke produced both during non-flaming and flaming combustion; 2) mass loss rates as a function of temperature to determine ease of thermal decomposition; and 3) mass loss rates and times to ignition as a function of incident heat flux. This paper describes the experiments that were conducted, their results, and the development of a set of parameters that could possibly be used to assess the overall fire hazard of combustible materials using small scale laboratory experiments. PMID:29599565

Some relevant parameters for assessing fire hazards of combustible mine materials using laboratory scale experiments.

PubMed

Litton, Charles D; Perera, Inoka E; Harteis, Samuel P; Teacoach, Kara A; DeRosa, Maria I; Thomas, Richard A; Smith, Alex C

2018-04-15

When combustible materials ignite and burn, the potential for fire growth and flame spread represents an obvious hazard, but during these processes of ignition and flaming, other life hazards present themselves and should be included to ensure an effective overall analysis of the relevant fire hazards. In particular, the gases and smoke produced both during the smoldering stages of fires leading to ignition and during the advanced flaming stages of a developing fire serve to contaminate the surrounding atmosphere, potentially producing elevated levels of toxicity and high levels of smoke obscuration that render the environment untenable. In underground mines, these hazards may be exacerbated by the existing forced ventilation that can carry the gases and smoke to locations far-removed from the fire location. Clearly, materials that require high temperatures (above 1400 K) and that exhibit low mass loss during thermal decomposition, or that require high heat fluxes or heat transfer rates to ignite represent less of a hazard than materials that decompose at low temperatures or ignite at low levels of heat flux. In order to define and quantify some possible parameters that can be used to assess these hazards, small-scale laboratory experiments were conducted in a number of configurations to measure: 1) the toxic gases and smoke produced both during non-flaming and flaming combustion; 2) mass loss rates as a function of temperature to determine ease of thermal decomposition; and 3) mass loss rates and times to ignition as a function of incident heat flux. This paper describes the experiments that were conducted, their results, and the development of a set of parameters that could possibly be used to assess the overall fire hazard of combustible materials using small scale laboratory experiments.

Two-phase nanofluid-based thermal management systems for LED cooling

NASA Astrophysics Data System (ADS)

Kiseev, V.; Aminev, D.; Sazhin, O.

2017-04-01

This research focuses on two-phase thermal control systems, namely loop thermosyphons (LTS) filled with nanofluids, and their use as LED cooling devices. The behavior of the fluid in the thermosyphons and the mechanisms explaining the possible impact of nanoparticles on thermal properties of the working fluid as well as the processes in the LTS are addressed. Nanoparticle distribution in the nanofluid, methods of preparation of nanofluids and nanofluid degradation processes (aging) are studied. The results are obtained from a set of experiments on thermosyphon characteristics depending on the thermophysical properties of the working fluid, filling volume, geometry and materials of radiators. The impact of nanofluids on heat-transfer process occurring inside thermosyphon is also studied. Results indicate strong influence of nanoparticles on the thermal properties of the thermosyphons, with up to 20% increase of the heat transfer coefficient. Additionally, a method of calculating the hydrodynamic limit of the LTS is proposed, which allows for estimation of the maximum heat flux that can be transferred by means of the LTS. Possible ways for further improvement of the model are proposed. The nanofluids are shown to be effective means of enhancing two-phase systems of thermal management.

Large-scale Generation of Patterned Bubble Arrays on Printed Bi-functional Boiling Surfaces

NASA Astrophysics Data System (ADS)

Choi, Chang-Ho; David, Michele; Gao, Zhongwei; Chang, Alvin; Allen, Marshall; Wang, Hailei; Chang, Chih-Hung

2016-04-01

Bubble nucleation control, growth and departure dynamics is important in understanding boiling phenomena and enhancing nucleate boiling heat transfer performance. We report a novel bi-functional heterogeneous surface structure that is capable of tuning bubble nucleation, growth and departure dynamics. For the fabrication of the surface, hydrophobic polymer dot arrays are first printed on a substrate, followed by hydrophilic ZnO nanostructure deposition via microreactor-assisted nanomaterial deposition (MAND) processing. Wettability contrast between the hydrophobic polymer dot arrays and aqueous ZnO solution allows for the fabrication of heterogeneous surfaces with distinct wettability regions. Heterogeneous surfaces with various configurations were fabricated and their bubble dynamics were examined at elevated heat flux, revealing various nucleate boiling phenomena. In particular, aligned and patterned bubbles with a tunable departure frequency and diameter were demonstrated in a boiling experiment for the first time. Taking advantage of our fabrication method, a 6 inch wafer size heterogeneous surface was prepared. Pool boiling experiments were also performed to demonstrate a heat flux enhancement up to 3X at the same surface superheat using bi-functional surfaces, compared to a bare stainless steel surface.

Initial results from the NASA Lewis Bumpy Torus experiment. [of steady-state ion heating method based on modified Penning discharge

NASA Technical Reports Server (NTRS)

Roth, J. R.; Richardson, R. W.; Gerdin, G. A.

1973-01-01

Initial results were obtained from low power operation of the NASA Lewis Bumpy Torus experiment, in which a steady-state ion heating method based on the modified Penning discharge is applied in a bumpy torus confinement geometry. The magnet facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 T, equally spaced in a toroidal array 1.52 m in major diameter. A 18 cm i.d. anode ring is located at each of the 12 midplanes and is maintained at high positive potentials by a dc power supply. Initial observations indicate electron temperatures from 10 to 150 eV, and ion kinetic temperatures from 200 eV to 1200 eV. Two modes of operation were observed, which depend on background pressure, and have different radial density profiles. Steady state neutron production was observed. The ion heating process in the bumpy torus appears to parallel closely the mechanism observed when the modified Penning discharge was operated in a simple magnetic mirror field.

Experimental examination of a targeted hyperthermia system using inductively heated ferromagnetic microspheres in rabbit kidney

NASA Astrophysics Data System (ADS)

Jones, S. K.; Winter, J. G.

2001-02-01

It is known that significant heating can be generated by magnetic hysteresis effects in small ferromagnetic particles exposed to a rapidly alternating magnetic field. If such particles can be made to infiltrate the vascular bed surrounding a tumour by intravascular infusion then it may be possible to generate sufficient heating to destroy the tumour by hyperthermia. One of the constraints on such a technique is the limited amount of magnetic material that can be delivered to a tumour via the intravascular route and the consequent heating that can be induced by this material. Here, we report on a series of experiments in which doses of microspheres containing different amounts of ferromagnetic material were infused into rabbit kidneys via the renal artery with the aim of testing whether adequate tissue heating could be achieved using realistic concentrations of the embolised material. Heating rates were measured for each infused quantity under similar conditions with the animal alive and dead to examine the role of blood flow in the heating process. The results show that tissue temperatures above the therapeutic threshold of 42 °C can be readily achieved using this method with clinically relevant concentrations of microspheres in living tissue.

Heat exchange between a bouncing drop and a superhydrophobic substrate

PubMed Central

Shiri, Samira; Bird, James C.

2017-01-01

The ability to enhance or limit heat transfer between a surface and impacting drops is important in applications ranging from industrial spray cooling to the thermal regulation of animals in cold rain. When these surfaces are micro/nanotextured and hydrophobic, or superhydrophobic, an impacting drop can spread and recoil over trapped air pockets so quickly that it can completely bounce off the surface. It is expected that this short contact time limits heat transfer; however, the amount of heat exchanged and precise role of various parameters, such as the drop size, are unknown. Here, we demonstrate that the amount of heat exchanged between a millimeter-sized water drop and a superhydrophobic surface will be orders of magnitude less when the drop bounces than when it sticks. Through a combination of experiments and theory, we show that the heat transfer process on superhydrophobic surfaces is independent of the trapped gas. Instead, we find that, for a given spreading factor, the small fraction of heat transferred is controlled by two dimensionless groupings of physical parameters: one that relates the thermal properties of the drop and bulk substrate and the other that characterizes the relative thermal, inertial, and capillary dynamics of the drop. PMID:28630306

Origin of two maxima in specific heat in enthalpy relaxation under thermal history composed of cooling, annealing, and heating.

PubMed

Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

2016-12-01

The origin of two maxima in specific heat observed at the higher and the lower temperatures in the glass-transition region in the heating process has been studied for polymethyl methacrylate and polyvinyl chloride using differential scanning calorimetry, and the calculation was done using the phenomenological model equation under a thermal history of the typical annealing experiment composed of cooling, annealing, and heating. The higher maximum is observed above the glass-transition temperature, and it remains almost unchanged independent of annealing time t_{a}, while the lower one is observed above an annealing temperature T_{a} and shifts toward the higher one, increasing its magnitude with t_{a}. The analysis by the phenomenological model equation proposed in order to interpret the memory effect in the glassy state clarifies that under a typical annealing history, two maxima in specific heat essentially appear. The shift of the lower maximum toward higher temperatures from above T_{a} is caused by an increase in the amount of relaxation during annealing with t_{a}. The annealing temperature and the amount of relaxation during annealing play a major role in the determination of the number of maxima in the specific heat.

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows.

PubMed

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-06-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future.

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows*

PubMed Central

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-01-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future. PMID:26055916

The viking biological investigation: preliminary results.

PubMed

Klein, H P; Horowitz, N H; Levin, G V; Oyama, V I; Lederberg, J; Rich, A; Hubbard, J S; Hobby, G L; Straat, P A; Berdahl, B J; Carle, G C; Brown, F S; Johnson, R D

1976-10-01

Three different types of biological experiments on samples of martian surface material ("soil") were conducted inside the Viking lander. In the carbon assimilation or pyrolytic release experiment, (14)CO(2) and (14)CO were exposed to soil in the presence of light. A small amount of gas was found to be converted into organic material. Heat treatment of a duplicate sample prevented such conversion. In the gas exchange experiment, soil was first humidified (exposed to water vapor) for 6 sols and then wet with a complex aqueous solution of metabolites. The gas above the soil was monitored by gas chromatography. A substantial amount of O(2) was detected in the first chromatogram taken 2.8 hours after humidification. Subsequent analyses revealed that significant increases in CO(2) and only small changes in N(2) had also occurred. In the labeled release experiment, soil was moistened with a solution containing several (14)C-labeled organic compounds. A substantial evolution of radioactive gas was registered but did not occur with a duplicate heat-treated sample. Alternative chemical and biological interpretations are possible for these preliminary data. The experiments are still in process, and these results so far do not allow a decision regarding the existence of life on the plonet Mars.

Understanding Wave-mean Flow Feedbacks and Tropospheric Annular Variability

NASA Astrophysics Data System (ADS)

Lorenz, D. J.

2016-12-01

The structure of internal tropospheric variability is important for determining the impact of the stratosphere on the troposphere. This study aims to better understand the fundamental dynamical mechanisms that control the feedbacks between the eddies and the mean flow, which in turn select the tropospheric annular mode. Recent work using Rossby Wave Chromatography suggests that "barotropic processes", which directly impact the meridional propagation of wave activity (specifically the reflectivity of the poleward flank of the mid-latitude jet), are more important for the positive feedback between the annular mode and the eddies than "baroclinic processes", which involve changes in the generation of wave activity by baroclinic instability. In this study, experiments with a fully nonlinear quasi-geostrophic model are discussed which provide independent confirmation of the importance of barotropic versus baroclinic processes. The experiments take advantage of the steady-state balance at upper-levels between the meridional gradient in diabatic heating and the second derivative of the upper-level EP flux divergence. Simulations with standard Newtonian heating are compared to simulations with constant-in-time heating taken from the climatology of the standard run and it is found that the forced annular mode response to changes in surface friction is very similar. Moreover, as expected from the annular mode response, the eddy momentum fluxes are also very similar. This is despite the fact that the upper-level EP flux divergence is very different between the two simulations (upper-level EP flux divergence must remain constant in the constant heating simulation while in the standard simulation there is no such constraint). The upper-level balances are maintained by a large change in the baroclinic wave source (i.e. vertical EP flux), which is accompanied by little momentum flux change. Therefore the eddy momentum fluxes appear to be relatively insensitive to the wave activity source. A more detailed comparison suggests a helpful rule-of-thumb relating the amplitude of the baroclinic wave source to the upper-level vorticity flux forced by this wave source.

Experiments and numerical simulations of flow field and heat transfer coefficients inside an autoclave model

NASA Astrophysics Data System (ADS)

Ghamlouch, T.; Roux, S.; Bailleul, J.-L.; Lefèvre, N.; Sobotka, V.

2017-10-01

Today's aerospace industrial first priority is the quality improvement of the composite material parts with the reduction of the manufacturing time in order to increase their quality/cost ratio. A fabrication method that could meet these specifications especially for large parts is the autoclave curing process. In fact the autoclave molding ensures the thermal control of the composite parts during the whole curing cycle. However the geometry of the tools as well as their positioning in the autoclave induce non uniform and complex flows around composite parts. This heterogeneity implies non-uniform heat transfers which can directly impact on part quality. One of the main challenges is therefore to describe the flow field inside an autoclave as well as the convective heat transfer from the heated pressurized gas to the composite part and the mold. For this purpose, and given the technical issues associated with instrumentation and measurements in actual autoclaves, an autoclave model was designed and then manufactured based on similarity laws. This tool allows the measurement of the flow field around representative real industrial molds using the PIV technique and the characterization of the heat transfer thanks to thermal instrumentation. The experimental results are then compared with those derived from numerical simulations using a commercial RANS CFD code. This study aims at developing a semi-empirical approach for the prediction of the heat transfer coefficient around the parts and therefore predicts its thermal history during the process with a view of optimization.

The Sensitivity of the Midlatitude Moist Isentropic Circulation on Both Sides of the Climate Model Hierarchy

NASA Astrophysics Data System (ADS)

Fajber, R. A.; Kushner, P. J.; Laliberte, F. B.

2017-12-01

In the midlatitude atmosphere, baroclinic eddies are able to raise warm, moist air from the surface into the midtroposphere where it condenses and warms the atmosphere through latent heating. This coupling between dynamics and moist thermodynamics motivates using a conserved moist thermodynamic variable, such as the equivalent potential temperature, to study the midlatitude circulation and associated heat transport since it implicitly accounts for latent heating. When the equivalent potential temperature is used to zonally average the circulation, the moist isentropic circulation takes the form of a single cell in each hemisphere. By utilising the statistical transformed Eulerian mean (STEM) circulation we are able to parametrize the moist isentropic circulation in terms of second order dynamic and moist thermodynamic statistics. The functional dependence of the STEM allows us to analytically calculate functional derivatives that reveal the spatially varying sensitivity of the moist isentropic circulation to perturbations in different statistics. Using the STEM functional derivatives as sensitivity kernels we interpret changes in the moist isentropic circulation from two experiments: surface heating in an idealised moist model, and a climate change scenario in a comprehensive atmospheric general circulation model. In both cases we find that the changes in the moist isentropic circulation are well predicted by the functional sensitivities, and that the total heat transport is more sensitive to changes in dynamical processes driving local changes in poleward heat transport than it is to thermodynamic and/or radiative processes driving changes to the distribution of equivalent potential temperature.

Effect of Heat Input on Geometry of Austenitic Stainless Steel Weld Bead on Low Carbon Steel

NASA Astrophysics Data System (ADS)

Saha, Manas Kumar; Hazra, Ritesh; Mondal, Ajit; Das, Santanu

2018-05-01

Among different weld cladding processes, gas metal arc welding (GMAW) cladding becomes a cost effective, user friendly, versatile method for protecting the surface of relatively lower grade structural steels from corrosion and/or erosion wear by depositing high grade stainless steels onto them. The quality of cladding largely depends upon the bead geometry of the weldment deposited. Weld bead geometry parameters, like bead width, reinforcement height, depth of penetration, and ratios like reinforcement form factor (RFF) and penetration shape factor (PSF) determine the quality of the weld bead geometry. Various process parameters of gas metal arc welding like heat input, current, voltage, arc travel speed, mode of metal transfer, etc. influence formation of bead geometry. In the current experimental investigation, austenite stainless steel (316) weld beads are formed on low alloy structural steel (E350) by GMAW using 100% CO2 as the shielding gas. Different combinations of current, voltage and arc travel speed are chosen so that heat input increases from 0.35 to 0.75 kJ/mm. Nine number of weld beads are deposited and replicated twice. The observations show that weld bead width increases linearly with increase in heat input, whereas reinforcement height and depth of penetration do not increase with increase in heat input. Regression analysis is done to establish the relationship between heat input and different geometrical parameters of weld bead. The regression models developed agrees well with the experimental data. Within the domain of the present experiment, it is observed that at higher heat input, the weld bead gets wider having little change in penetration and reinforcement; therefore, higher heat input may be recommended for austenitic stainless steel cladding on low alloy steel.

Using Waste Heat for External Processes (English/Chinese) (Fact Sheet) (in Chin3se; English)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Chinese translation of the Using Waste Heat for External Processes fact sheet. Provides suggestions on how to use waste heat in industrial applications. The temperature of exhaust gases from fuel-fired industrial processes depends mainly on the process temperature and the waste heat recovery method. Figure 1 shows the heat lost in exhaust gases at various exhaust gas temperatures and percentages of excess air. Energy from gases exhausted from higher temperature processes (primary processes) can be recovered and used for lower temperature processes (secondary processes). One example is to generate steam using waste heat boilers for the fluid heaters used inmore » petroleum crude processing. In addition, many companies install heat exchangers on the exhaust stacks of furnaces and ovens to produce hot water or to generate hot air for space heating.« less

Anode energy transfer in a transient arc

NASA Astrophysics Data System (ADS)

Valensi, F.; Ratovoson, P.; Razafinimanana, M.; Gleizes, A.

2017-04-01

This work deals with experimental investigation of a transient arc. Arc configuration and electrode erosion were studied in order to quantify the energy transfer to the electrodes as a function of maximal current, time constant and electrodes material. Experiments with two consecutive arcs allow demonstrating non stationary behaviour of the arc electrode interaction. This is due to the fact that while the duration of the experiments is far larger than plasma phenomena time constants, it is comparable to those of electrode heating and melting processes.

Transmitter experiment package for the communications technology satellite

NASA Technical Reports Server (NTRS)

Farber, B.; Goldin, D. S.; Marcus, B.; Mock, P.

1977-01-01

The operating requirements, system design characteristics, high voltage packaging considerations, nonstandard components development, and test results for the transmitter experiment package (TEP) are described. The TEP is used for broadcasting power transmission from the Communications Technology Satellite. The TEP consists of a 12 GHz, 200-watt output stage tube (OST), a high voltage processing system that converts the unregulated spacecraft solar array power to the regulated voltages required for OST operation, and a variable conductance heat pipe system that is used to cool the OST body.

Modeling nuclear processes by Simulink

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashid, Nahrul Khair Alang Md, E-mail: nahrul@iium.edu.my

2015-04-29

Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox softwaremore » that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples.« less

Artificial plasma cusp generated by upper hybrid instabilities in HF heating experiments at HAARP

NASA Astrophysics Data System (ADS)

Kuo, Spencer; Snyder, Arnold

2013-05-01

High Frequency Active Auroral Research Program digisonde was operated in a fast mode to record ionospheric modifications by the HF heating wave. With the O mode heater of 3.2 MHz turned on for 2 min, significant virtual height spread was observed in the heater off ionograms, acquired beginning the moment the heater turned off. Moreover, there is a noticeable bump in the virtual height spread of the ionogram trace that appears next to the plasma frequency (~ 2.88 MHz) of the upper hybrid resonance layer of the HF heating wave. The enhanced spread and the bump disappear in the subsequent heater off ionograms recorded 1 min later. The height distribution of the ionosphere in the spread situation indicates that both electron density and temperature increases exceed 10% over a large altitude region (> 30 km) from below to above the upper hybrid resonance layer. This "mini cusp" (bump) is similar to the cusp occurring in daytime ionograms at the F1-F2 layer transition, indicating that there is a small ledge in the density profile reminiscent of F1-F2 layer transitions. Two parametric processes exciting upper hybrid waves as the sidebands by the HF heating waves are studied. Field-aligned purely growing mode and lower hybrid wave are the respective decay modes. The excited upper hybrid and lower hybrid waves introduce the anomalous electron heating which results in the ionization enhancement and localized density ledge. The large-scale density irregularities formed in the heat flow, together with the density irregularities formed through the parametric instability, give rise to the enhanced virtual height spread. The results of upper hybrid instability analysis are also applied to explain the descending feature in the development of the artificial ionization layers observed in electron cyclotron harmonic resonance heating experiments.

Measurements of Doppler-ion temperature and flow in the multi-pulsing CHI experiment on HIST

NASA Astrophysics Data System (ADS)

Hanao, T.; Ishihara, M.; Hirono, H.; Hyobu, T.; Ito, K.; Matsumoto, K.; Nakayama, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

The steady-state current sustainment of spherical torus (ST) configurations is expected to be achieved by Multi-pulsing Coaxial Helicity Injection (M-CHI) method. In the double-pulsing discharges, the plasma current can be sustained much longer against the resistive decay compared to the single CHI. The M-CHI has capabilities as a static ion heating method. Ion Doppler Spectrometer (IDS) measurements confirmed a significant increase in the ion temperature after the second CHI pulse. The ion heating mechanism is an important issue to be explored in the M-CHI experiments. It is considered due to the magnetic reconnection process of plasmoids and/or the damping of the Alfven wave. The ion heating becomes suppressed around the separatrix layer in the high field side where the amplitude of the magnetic fluctuations is minimized due to the poloidal flow shear. The shear flow generation is caused by ExB drift and ion diamagnetic drift. The contribution from the diamagnetic drift on the shear flow can be evaluated by measuring the flow velocity of hydrogen and impurity ions by using Mach probe and IDS. We will discuss the dependence of the ion heating characteristics on the variation of the density gradient by varying TF coil current.

Thermal anomalies of the transmitter experiment package on the communications technology satellite

NASA Technical Reports Server (NTRS)

Alexovich, R. E.; Curren, A. N.

1979-01-01

The causes of four temporary thermal-control-system malfunctions that gave rise to unexpected temperature excursions in the 12-gigahertz, 200-watt transmitter experiment package (TEP) on the Communications Technology Satellite were investigated. The TEP consists of a nominal 200-watt output stage tube (OST), a supporting power-processing system (PPS), and a variable-conductance heat-pipe system (VCHPS). The VCHPS, which uses three heat pipes to conduct heat from the body of the OST to a radiator fin, was designed to maintain the TEP at safe operating temperatures at all operating conditions. On four occasions during 1977, all near the spring and fall equinoxes, the OST body temperature and related temperatures displayed sudden, rapid, and unexpected rises above normal levels while the TEP was operating at essentially constant, normal conditions. The temperature excursions were terminated without TEP damage by reducing the radio frequency (RF) output power of the OST. Between the anomalies and since the fourth, the thermal control system has apparently functioned as designed. The results indicate the most probable cause of the temperature anomalies is depriming of the arteries in the variable-conductance heat pipes. A mode was identified in which the TEP, as presently configured, may operate with stable temperatures and with minimum change in performance level.

Male-Specific Coliphages as Indicators of Thermal Inactivation of Pathogens in Biosolids

PubMed Central

Nappier, Sharon P.; Aitken, Michael D.; Sobsey, Mark D.

2006-01-01

Male-specific (F+) coliphages have been proposed as a candidate indicator of fecal contamination and of virus reduction in waste treatment. However, in this and earlier work with a laboratory thermophilic anaerobic digester, a heat-resistant fraction of F+ coliphage populations indigenous to municipal wastewater and sludge was evident. We therefore isolated coliphages from municipal wastewater sludge and from biosolid samples after thermophilic anaerobic digestion to evaluate the susceptibility of specific groups to thermal inactivation. Similar numbers of F+ DNA and F+ RNA coliphages were found in untreated sludge, but the majority of isolates in digested biosolids were group I F+ RNA phages. Separate experiments on individual isolates at 53°C confirmed the apparent heat resistance of group I F+ RNA coliphages as well as the susceptibility of group III F+ RNA coliphages. Although few F+ DNA coliphages were recovered from the treated biosolid samples, thermal inactivation experiments indicated heat resistance similar to that of group I F+ RNA phages. Hence, F+ DNA coliphage reductions during thermophilic anaerobic digestion are probably related to mechanisms other than thermal inactivation. Further studies should focus on the group III F+ RNA coliphages as potential indicators of reductions of heat-resistant pathogens in thermal processes for sludge treatment. PMID:16597945

Numerical Simulation and Experimental Validation of MIG Welding of T-Joints of Thin Aluminum Plates for Top Class Vehicles

NASA Astrophysics Data System (ADS)

Bonazzi, Enrico; Colombini, Elena; Panari, Davide; Vergnano, Alberto; Leali, Francesco; Veronesi, Paolo

2017-01-01

The integration of experiments with numerical simulations can efficiently support a quick evaluation of the welded joint. In this work, the MIG welding operation on aluminum T-joint thin plate has been studied by the integration of both simulation and experiments. The aim of the paper is to enlarge the global database, to promote the use of thin aluminum sheets in automotive body industries and to provide new data. Since the welding of aluminum thin plates is difficult to control due to high speed of the heat source and high heat flows during heating and cooling, a simulation model could be considered an effective design tool to predict the real phenomena. This integrated approach enables new evaluation possibilities on MIG-welded thin aluminum T-joints, as correspondence between the extension of the microstructural zones and the simulation parameters, material hardness, transient 3D temperature distribution on the surface and inside the material, stresses, strains, and deformations. The results of the mechanical simulations are comparable with the experimental measurements along the welding path, especially considering the variability of the process. The results could well predict the welding-induced distortion, which together with local heating during welding must be anticipated and subsequently minimized and counterbalance.

Parameters optimization of laser brazing in crimping butt using Taguchi and BPNN-GA

NASA Astrophysics Data System (ADS)

Rong, Youmin; Zhang, Zhen; Zhang, Guojun; Yue, Chen; Gu, Yafei; Huang, Yu; Wang, Chunming; Shao, Xinyu

2015-04-01

The laser brazing (LB) is widely used in the automotive industry due to the advantages of high speed, small heat affected zone, high quality of welding seam, and low heat input. Welding parameters play a significant role in determining the bead geometry and hence quality of the weld joint. This paper addresses the optimization of the seam shape in LB process with welding crimping butt of 0.8 mm thickness using back propagation neural network (BPNN) and genetic algorithm (GA). A 3-factor, 5-level welding experiment is conducted by Taguchi L25 orthogonal array through the statistical design method. Then, the input parameters are considered here including welding speed, wire speed rate, and gap with 5 levels. The output results are efficient connection length of left side and right side, top width (WT) and bottom width (WB) of the weld bead. The experiment results are embed into the BPNN network to establish relationship between the input and output variables. The predicted results of the BPNN are fed to GA algorithm that optimizes the process parameters subjected to the objectives. Then, the effects of welding speed (WS), wire feed rate (WF), and gap (GAP) on the sum values of bead geometry is discussed. Eventually, the confirmation experiments are carried out to demonstrate the optimal values were effective and reliable. On the whole, the proposed hybrid method, BPNN-GA, can be used to guide the actual work and improve the efficiency and stability of LB process.

The influence of double-diffusive processes on the melting of ice in the Arctic Ocean: laboratory analogue experiments and their interpretation

NASA Astrophysics Data System (ADS)

Turner, J. S.; Veronis, G.

2004-03-01

This study has been motivated by two oceanographic observations: an increased rate of melting of sea ice in the Arctic Ocean, and the advance of an anomalously warm tongue of Atlantic water across the Arctic below the halocline over the last few decades. A series of laboratory experiments has been carried out in order to explore the physical principles underlying these phenomena, and the possibility that the extra heating at depth is responsible for the enhanced melting rate. A tank was filled with salt solution having various constant vertical density gradients. A block of ice one third of the length of the tank was floated on the surface at one end, and the rest of the surface and the walls of the tank were insulated. When no extra heat was supplied the melting rate (loss of weight of the ice in 1 h) systematically decreased as the stratification was changed from homogeneous fluid to increasingly large density gradients, while keeping the salinity of the solution in contact with the ice constant. An analogue of the intruding Atlantic water was produced by heating the lower portion of the vertical end wall at the end of the tank opposite to the ice end, keeping its temperature constant, and using the same range of salinity gradients as in the unheated experiments. Again the melting rate decreased as the density gradient was increased, but for low gradients it was larger than that in the unheated experiments. Above a certain intermediate gradient there was no significant difference in melting rate between the unheated and heated runs. The melting data were supplemented by photographs and vertical temperature and salinity profiles. The upward transfer of heat from the body of the fluid to melt the ice was clearly double-diffusive: overturning layers, separated by 'diffusive' interfaces, were visible on shadowgraphs, and the thickness of the layers decreased as the density gradient increased. The mean thickness of the layers through the depth of the tank also systematically decreased as the density gradient increased. With weak gradients an extra heat flux to the ice came from the intruding heated layer, but at large gradients this tongue of warm water at depth did not add to the flux near the surface. Though they were obtained in a simple, arbitrary and fixed geometry, we believe that the results of these experiments can be used as the basis for a better physical understanding of the melting rates of ice in the Arctic under various conditions.

Heat and Mass Transfer Processes in Scrubber of Flue Gas Heat Recovery Device

NASA Astrophysics Data System (ADS)

Veidenbergs, Ivars; Blumberga, Dagnija; Vigants, Edgars; Kozuhars, Grigorijs

2010-01-01

The paper deals with the heat and mass transfer process research in a flue gas heat recovery device, where complicated cooling, evaporation and condensation processes are taking place simultaneously. The analogy between heat and mass transfer is used during the process of analysis. In order to prepare a detailed process analysis based on heat and mass process descriptive equations, as well as the correlation for wet gas parameter calculation, software in the Microsoft Office Excel environment is being developed.

Effect of Graphitic Content on Carbon Supported Catalyst Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Anant; Artyushkova, Kateryna; Atanassov, Plamen

2011-07-01

The effect of graphitic content on carbon supported platinum catalysts was investigated in order to investigate its influence on catalyst performance. Four catalysts of varying surface areas and graphitic content were analyzed using XPS, HREELS, and tested using RDE experiments. The catalysts were also heat treated at 150oC and 100%RH as means to uniformly age them. The heat treated samples were analyzed using the same methods to determine what changes had occurred due to this aging process. When compared to the BOL catalysts, heat treated catalysts displayed increased graphitic carbon and platinum metalic content, however they also showed depressed catalyticmore » activity. The primary cause is still under investigation, though it is believed to be related to loss of amorphous carbon content.« less

Compact heat and mass exchangers of the plate fin type in thermal sorption systems: Application in an absorption heat pump with the working pair CH3OH-LiBr/ZnBr2

NASA Astrophysics Data System (ADS)

Becker, Harry

The possible application of Compact Heat and Mass Exchangers (CHME) in a gas fired Absorption Heat Pump (AHP) for domestic heating is studied. The above mentioned heat and mass exchangers are of the plate type. The space between the parallel and plain plates is filled up with corrugated plates of a certain height. The plain and finned plates are stacked and welded together. This gives a heat and mass exchanger which is very compact, expressed by a high area density (m2/m3). This leads to heat and mass transfer processes with small temperature and concentration differences. For testing purposes a pilot plant was built using the above type of components in order to test their heat and/or mass transfer performance. Only the generator is of the Shell And Tube (SAT) type. As the working pair, CH3OH - LiBr/ ZnBr2 was chosen, with the alcohol as the solvent and the salt mixture as the absorbent. This leads to sub atmospheric working pressures with only solvent in the vapor phase. Three series of experiments have been carried out, during which the input parameters were varied over a certain range. It is concluded that the plate fin CHMES are very suitable for application in an AHP for domestic heating purposes.

EEG frequency tagging using ultra-slow periodic heat stimulation of the skin reveals cortical activity specifically related to C fiber thermonociceptors

PubMed Central

Colon, Elisabeth; Liberati, Giulia; Mouraux, André

2017-01-01

The recording of event-related brain potentials triggered by a transient heat stimulus is used extensively to study nociception and diagnose lesions or dysfunctions of the nociceptive system in humans. However, these responses are related exclusively to the activation of a specific subclass of nociceptive afferents: quickly-adapting thermonociceptors. In fact, except if the activation of Aδ fibers is avoided or if A fibers are blocked, these responses specifically reflect activity triggered by the activation of Type 2 quickly-adapting A fiber mechano-heat nociceptors (AMH-2). Here, we propose a novel method to isolate, in the human electroencephalogram (EEG), cortical activity related to the sustained periodic activation of heat-sensitive thermonociceptors, using very slow (0.2 Hz) and long-lasting (75 s) sinusoidal heat stimulation of the skin between baseline and 50°C. In a first experiment, we show that when such long-lasting thermal stimuli are applied to the hand dorsum of healthy volunteers, the slow rises and decreases of skin temperature elicit a consistent periodic EEG response at 0.2 Hz and its harmonics, as well as a periodic modulation of the magnitude of theta, alpha and beta band EEG oscillations. In a second experiment, we demonstrate using an A fiber block that these EEG responses are predominantly conveyed by unmyelinated C fiber nociceptors. The proposed approach constitutes a novel mean to study C fiber function in humans, and to explore the cortical processing of tonic heat pain in physiological and pathological conditions. PMID:27871921