Effects of Combined Surface and In-Depth Absorption on Ignition of PMMA

PubMed Central

Gong, Junhui; Chen, Yixuan; Li, Jing; Jiang, Juncheng; Wang, Zhirong; Wang, Jinghong

2016-01-01

A one-dimensional numerical model and theoretical analysis involving both surface and in-depth radiative heat flux absorption are utilized to investigate the influence of their combination on ignition of PMMA (Polymethyl Methacrylate). Ignition time, transient temperature in a solid and optimized combination of these two absorption modes of black and clear PMMA are examined to understand the ignition mechanism. Based on the comparison, it is found that the selection of constant or variable thermal parameters of PMMA barely affects the ignition time of simulation results. The linearity between tig−0.5 and heat flux does not exist anymore for high heat flux. Both analytical and numerical models underestimate the surface temperature and overestimate the temperature in a solid beneath the heat penetration layer for pure in-depth absorption. Unlike surface absorption circumstances, the peak value of temperature is in the vicinity of the surface but not on the surface for in-depth absorption. The numerical model predicts the ignition time better than the analytical model due to the more reasonable ignition criterion selected. The surface temperature increases with increasing incident heat flux. Furthermore, it also increases with the fraction of surface absorption and the radiative extinction coefficient for fixed heat flux. Finally, the combination is optimized by ignition time, temperature distribution in a solid and mass loss rate. PMID:28773940

Effects of Combined Surface and In-Depth Absorption on Ignition of PMMA.

PubMed

Gong, Junhui; Chen, Yixuan; Li, Jing; Jiang, Juncheng; Wang, Zhirong; Wang, Jinghong

2016-10-05

A one-dimensional numerical model and theoretical analysis involving both surface and in-depth radiative heat flux absorption are utilized to investigate the influence of their combination on ignition of PMMA (Polymethyl Methacrylate). Ignition time, transient temperature in a solid and optimized combination of these two absorption modes of black and clear PMMA are examined to understand the ignition mechanism. Based on the comparison, it is found that the selection of constant or variable thermal parameters of PMMA barely affects the ignition time of simulation results. The linearity between t ig -0.5 and heat flux does not exist anymore for high heat flux. Both analytical and numerical models underestimate the surface temperature and overestimate the temperature in a solid beneath the heat penetration layer for pure in-depth absorption. Unlike surface absorption circumstances, the peak value of temperature is in the vicinity of the surface but not on the surface for in-depth absorption. The numerical model predicts the ignition time better than the analytical model due to the more reasonable ignition criterion selected. The surface temperature increases with increasing incident heat flux. Furthermore, it also increases with the fraction of surface absorption and the radiative extinction coefficient for fixed heat flux. Finally, the combination is optimized by ignition time, temperature distribution in a solid and mass loss rate.

An analytic formula for heating due to ozone absorption

NASA Technical Reports Server (NTRS)

Lindzen, R. S.; Will, D. I.

1972-01-01

An attempt was made to devise a simple expression or formula to describe radiative heating in the atmosphere by ozone absorption. Such absorption occurs in the Hartley, Huggins, and Chappuis bands and is only slightly temperature and pressure dependent.

Slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating

NASA Astrophysics Data System (ADS)

Mohamed, Muhammad Khairul Anuar; Noar, Nor Aida Zuraimi Md; Ismail, Zulkhibri; Kasim, Abdul Rahman Mohd; Sarif, Norhafizah Md; Salleh, Mohd Zuki; Ishak, Anuar

2017-08-01

Present study solved numerically the velocity slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating. The governing equations which in the form of partial differential equations are transformed to ordinary differential equations before being solved numerically using the Runge-Kutta-Fehlberg method in MAPLE. The numerical solution is obtained for the surface temperature, heat transfer coefficient, reduced skin friction coefficient as well as the temperature and velocity profiles. The flow features and the heat transfer characteristic for the pertinent parameter such as Prandtl number, stretching parameter, heat generation/absorption parameter, velocity slip parameter and conjugate parameter are analyzed and discussed.

Absorption Heat Pump Cycles

NASA Astrophysics Data System (ADS)

Kunugi, Yoshifumi; Kashiwagi, Takao

Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

NASA Astrophysics Data System (ADS)

Williams, Gareth O.; Künzel, S.; Daboussi, S.; Iwan, B.; Gonzalez, A. I.; Boutu, W.; Hilbert, V.; Zastrau, U.; Lee, H. J.; Nagler, B.; Granados, E.; Galtier, E.; Heimann, P.; Barbrel, B.; Dovillaire, G.; Lee, R. W.; Dunn, J.; Recoules, V.; Blancard, C.; Renaudin, P.; de la Varga, A. G.; Velarde, P.; Audebert, P.; Merdji, H.; Zeitoun, Ph.; Fajardo, M.

2018-02-01

We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. We compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data, suggestive of a temperature-dependent electronic structure in warm dense matter.

Variability of absorption heat pump efficiency for domestic water heating and space heating based on time-weighted bin analysis

DOE PAGES

Ally, Moonis Raza; Sharma, Vishaldeep

2017-11-02

Natural gas-driven absorption heat pumps are under renewed scrutiny as a viable technology for space conditioning and water heating for residential and commercial applications because of natural gas production trends, pricing, and the speculation that it might be a “bridge fuel” in the global transition towards energy sustainability. Since any level of natural gas combustion contributes to atmospheric carbon dioxide accumulation, the merits of natural gas consuming absorption technology are re-examined in this paper from the point of view of expected efficiency throughout the United States using a time-weighted bin temperature analysis. Such analyses are necessary because equipment standards formore » rated performance is restricted to one set ambient condition, whereas in actual practice, the absorption heat pump (AHP) must perform over a considerably wider range of external conditions, where its efficiency may be vastly different from that at the rated condition. Quantification of variation in efficiency and system performance are imperative to address how to provide the desired utility with the least environmental impact. In this paper, we examine limiting features in absorption heat pumps and relate it to systemic performances in sixteen cities across all eight climate zones in the U.S, each containing fifteen bin temperatures. The results indicate that the true expectation of performance of an AHP is significantly less than what might be optimized for the rated condition. Statistical measures of the variation in water heating COPs show that for most cities, the COP at the rated conditions is outside the 95% Confidence Interval. Moreover, it is concluded that deployment of absorption heat pump water heaters (AHPWH) may be restricted geographically by outdoor temperature constraints.« less

Variability of absorption heat pump efficiency for domestic water heating and space heating based on time-weighted bin analysis

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

Ally, Moonis Raza; Sharma, Vishaldeep

Natural gas-driven absorption heat pumps are under renewed scrutiny as a viable technology for space conditioning and water heating for residential and commercial applications because of natural gas production trends, pricing, and the speculation that it might be a “bridge fuel” in the global transition towards energy sustainability. Since any level of natural gas combustion contributes to atmospheric carbon dioxide accumulation, the merits of natural gas consuming absorption technology are re-examined in this paper from the point of view of expected efficiency throughout the United States using a time-weighted bin temperature analysis. Such analyses are necessary because equipment standards formore » rated performance is restricted to one set ambient condition, whereas in actual practice, the absorption heat pump (AHP) must perform over a considerably wider range of external conditions, where its efficiency may be vastly different from that at the rated condition. Quantification of variation in efficiency and system performance are imperative to address how to provide the desired utility with the least environmental impact. In this paper, we examine limiting features in absorption heat pumps and relate it to systemic performances in sixteen cities across all eight climate zones in the U.S, each containing fifteen bin temperatures. The results indicate that the true expectation of performance of an AHP is significantly less than what might be optimized for the rated condition. Statistical measures of the variation in water heating COPs show that for most cities, the COP at the rated conditions is outside the 95% Confidence Interval. Moreover, it is concluded that deployment of absorption heat pump water heaters (AHPWH) may be restricted geographically by outdoor temperature constraints.« less

The Modeling of Coupled Electromagnetic-Thermo-Mechanical Laser Interactions and Microstructural Behavior of Energetic Aggregates

DTIC Science & Technology

2015-01-01

analytical Beer - Lambert absorption profile to model laser heating of pure energetic crystals without considering any EM wave propagation effects...temperature. These aggregates were studied using both an analytical distribution for laser heating following Beer - Lambert absorption and the full EM finite...surface (ysurface - y) and material absorption coefficient, α, following a Beer - Lambert absorption relation given by , = !()

Contribution of particulate brown carbon to light absorption in the rural and urban Southeast US

NASA Astrophysics Data System (ADS)

Devi, J. Jai; Bergin, Michael H.; Mckenzie, Michael; Schauer, James J.; Weber, Rodney J.

2016-07-01

Measurements of wavelength dependent aerosol light absorption coefficients were carried out as part of the Southern Oxidant and Aerosol Study (SOAS) during the summer of 2013 to determine the contribution of light absorbing organic carbon (BrC) to total aerosol light absorption in a rural location (Centreville, AL) and an urban area (Atlanta, GA). The light absorption coefficients in the near UV and visible wavelengths were measured for both ambient air, as well as ambient air heated in a thermal denuder to 200 °C to remove the semi-volatile organic compounds. Atlanta measurements show dominance of semi-volatile brown carbon with an average absorption angstrom exponent (AAE) of 1.4 before heating and about 1.0 after heating. In urban Atlanta, a decrease of about ∼35% in the light absorption coefficient at 370 nm after heating indicates that light absorbing organic compounds are a substantial fraction of the light absorption budget. Furthermore, a considerable increase in the fraction of light absorption by the semi-volatile aerosol occurs during the daytime, likely linked with photochemistry. Measurements at rural Centerville, on the other hand, do not show any major change in AAE with values before and after heating of 0.99 and 0.98, respectively. Overall the results suggest that photochemical aged urban emissions result in the presence of light absorbing BrC, while at rural locations which are dominated by aged aerosol and local biogenic emissions (based on measurements of Angstrom exponents) BrC does not significantly contribute to light absorption.

Enhanced absorption cycle computer model

NASA Astrophysics Data System (ADS)

Grossman, G.; Wilk, M.

1993-09-01

Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

Experimental investigation of the heat and mass transfer in a tube bundle absorber of an absorption chiller

NASA Astrophysics Data System (ADS)

Olbricht, Michael; Luke, Andrea

2018-05-01

The design of the absorber of absorption chillers is still subject to great uncertainty since the coupled processes of heat and mass transfer as well as the influence of systemic interactions on the absorption process are not fully understood. Unfortunately, only a few investigations on the transport phenomena in the absorber during operation in an absorption chiller are reported in the literature. Therefore, experimental investigations on the heat and mass transfer during falling film absorption of steam in aqueous LiBr-solution are carried out in an absorber installed in an absorption chiller in this work. An improvement of heat and mass transfer due to the increase in convective effects are observed as the Ref number increases. Furthermore, an improvement of the heat transfer in the absorber with increasing coolant temperature can be identified in the systemic context. This is explained by a corresponding reduction in the average viscosity of the solution in the absorber. A comparison with experimental data from literature obtained from so-called absorber-generator test rigs shows a good consistency. Thus, it has been shown that the findings obtained on these simplified experimental setups can be transferred to the absorber in an absorption chiller. However, a comparison with correlations from the literature reveals a strong deviation between experimental and calculated results. Hence, further research activities on the development of better correlations are required in future.

Research of waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water

NASA Astrophysics Data System (ADS)

Zhang, Li; Zhang, Yu; Zhou, Liansheng; E, Zhijun; Wang, Kun; Wang, Ziyue; Li, Guohao; Qu, Bin

2018-02-01

The waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water has been analyzed. After the operation of heat pump, the influences on power generation and heat generation of unit were taken into account. In the light of the characteristics of heat pump in different operation stages, the energy efficiency of heat pump was evaluated comprehensively on both sides of benefits belonging to electricity and benefits belonging to heat, which adopted the method of contrast test. Thus, the reference of energy efficiency for same type projects was provided.

Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

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

Williams, Gareth O.; Künzel, S.; Daboussi, S.

We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. Here, we compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data,more » suggestive of a temperature-dependent electronic structure in warm dense matter.« less

Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

DOE PAGES

Williams, Gareth O.; Künzel, S.; Daboussi, S.; ...

2018-02-14

We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. Here, we compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data,more » suggestive of a temperature-dependent electronic structure in warm dense matter.« less

Energy and Exergy Analysis of Vapour Absorption Refrigeration Cycle—A Review

NASA Astrophysics Data System (ADS)

Kanabar, Bhaveshkumar Kantilal; Ramani, Bharatkumar Maganbhai

2016-07-01

In recent years, an energy crisis and the energy consumption have become global problems which restrict the sustainable growth. In these scenarios the scientific energy recovery and the utilization of various kinds of waste heat become very important. The waste heat can be utilized in many ways and one of the best practices is to use it for vapour absorption refrigeration system. To ensure efficient working of absorption cycle and utilization of optimum heat, exergy is the best tool for analysis. This paper provides the comprehensive picture of research and development of absorption refrigeration technology, practical and theoretical analysis with different arrangements of the cycle.

Ionospheric absorption, typical ionization, conductivity, and possible synoptic heating parameters in the upper atmosphere

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

Walker, J.K.; Bhatnagar, V.P.

1989-04-01

Relations for the average energetic particle heating and the typical Hall and Pedersen conductances, as functions of the ground-based Hf radio absorption, are determined. Collis and coworkers used the geosynchronous GEOS 2 particle data to relate or ''calibrate'' the auroral absorption on the same magnetic field lines with five levels of D region ionization. These ionospheric models are related to a Chapman layer that extends these models into the E region. The average energetic particle heating is calculated for each of these models using recent expressions for the effective recombination coefficient. The corresponding height-integrated heating rates are determined and relatedmore » to the absorption with a quadratic expression. The average Hall and Pedersen conductivities are calculated for each of the nominal absorption ionospheric models. The corresponding height-integrated conductances for nighttime conditions are determined and related to the absorption. Expressions for these conductances during disturbed sunlit conditions are also determined. These relations can be used in conjunction with simultaneous ground-based riometric and magnetic observations to determines the average Hall and Pedersen currents and the Joule heating. The typical daily rate of temperature increase in the mesosphere for storm conditions is several 10 K for both the energetic particle and the Joule heating. The increasing importance of these parameters of the upper and middle atmospheres is discussed. It is proposed that northern hemisphere ionospheric, current, and heating synoptic models and parameters be investigated for use on a regular basis. copyright American Geophysical Union 1989« less

Waste heat driven absorption refrigeration process and system

DOEpatents

Wilkinson, William H.

1982-01-01

Absorption cycle refrigeration processes and systems are provided which are driven by the sensible waste heat available from industrial processes and other sources. Systems are disclosed which provide a chilled water output which can be used for comfort conditioning or the like which utilize heat from sensible waste heat sources at temperatures of less than 170.degree. F. Countercurrent flow equipment is also provided to increase the efficiency of the systems and increase the utilization of available heat.

Triple effect absorption chiller utilizing two refrigeration circuits

DOEpatents

DeVault, Robert C.

1988-01-01

A triple effect absorption method and apparatus having a high coefficient of performance. Two single effect absorption circuits are combined with heat exchange occurring between a condenser and absorber of a high temperature circuit, and a generator of a low temperature circuit. The evaporators of both the high and low temperature circuits provide cooling to an external heat load.

Network Simulation solution of free convective flow from a vertical cone with combined effect of non- uniform surface heat flux and heat generation or absorption

NASA Astrophysics Data System (ADS)

Immanuel, Y.; Pullepu, Bapuji; Sambath, P.

2018-04-01

A two dimensional mathematical model is formulated for the transitive laminar free convective, incompressible viscous fluid flow over vertical cone with variable surface heat flux combined with the effects of heat generation and absorption is considered . using a powerful computational method based on thermoelectric analogy called Network Simulation Method (NSM0, the solutions of governing nondimensionl coupled, unsteady and nonlinear partial differential conservation equations of the flow that are obtained. The numerical technique is always stable and convergent which establish high efficiency and accuracy by employing network simulator computer code Pspice. The effects of velocity and temperature profiles have been analyzed for various factors, namely Prandtl number Pr, heat flux power law exponent n and heat generation/absorption parameter Δ are analyzed graphically.

LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

DOEpatents

Ko, Suk M.

1980-01-01

This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

Study of the effects of MeV Ag, Cu, Au, and Sn implantation on the optical properties of LiNbO3

NASA Technical Reports Server (NTRS)

Williams, E. K.; Ila, D.; Sarkisov, S.; Curley, M.; Poker, D. B.; Hensley, D. K.; Borel, C.

1998-01-01

The authors present the results of characterization of linear absorption and nonlinear refractive index of Au, Ag, Cu and Sn ion implantation into LiNbO3. Ag was implanted at 1.5 MeV to fluences of 2 to 17 x 17(exp 16)/sq cm at room temperature. Au and Cu were implanted to fluences of 5 to 20 x 10(exp 16)/sq cm at an energy of 2.0 MeV. Sn was implanted to a fluence of 1.6 x 10(exp 17)/sq cm at 160 kV. Optical absorption spectrometry indicated an absorption peak for the Au implanted samples after heat treatment at 1,000 C at approx. 620 nm. The Ag implanted samples absorption peaks shifted from approx. 450 nm before heat treatment to 550 nm after 500 C for 1h. Heat treatment at 800 C returned the Ag implanted crystals to a clear state. Cu nanocluster absorption peaks disappears at 500 C. No Sn clusters were observed by optical absorption or XRD. The size of the Ag and Au clusters as a function of heat treatment were determined from the absorption peaks. The Ag clusters did not change appreciably in size with heat treatment. The Au clusters increased from 3 to 9 nm diameter upon heat treatment at 1000 C. TEM analysis performed on a Au implanted crystal indicated the formation of Au nanocrystals with facets normal to the c-axis. Measurements of the nonlinear refractive indices were carried out using the Z-scan method with a tunable dye laser pumped by a frequency doubled mode-locked Nd:YAG laser. The dye laser had a 4.5 ps pulse duration time and 76 MHz pulse repetition rate (575 nm).

The economics of solar powered absorption cooling

NASA Technical Reports Server (NTRS)

Bartlett, J. C.

1978-01-01

Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.

Chemical reaction and heat generation/absorption aspects in MHD nonlinear convective flow of third grade nanofluid over a nonlinear stretching sheet with variable thickness

NASA Astrophysics Data System (ADS)

Qayyum, Sajid; Hayat, Tasawar; Alsaedi, Ahmed

Nonlinear thermal radiation and chemical reaction in magnetohydrodynamic (MHD) flow of third grade nanofluid over a stretching sheet with variable thickness are addressed. Heat generation/absorption and nonlinear convection are considered. The sheet moves with nonlinear velocity. Sheet is convectively heated. In addition zero mass flux condition for nanoparticle concentration is imposed. Results for velocity, temperature, concentration, skin friction and local Nusselt number are presented and examined. It is found that velocity and boundary layer thickness are increasing for Reynolds number. Temperature is a increasing function of the heat generation/absorption parameter while it causes a decrease in the heat transfer rate. Moreover effect of Brownian motion and chemical reaction on the concentration are quite reverse.

Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

NASA Technical Reports Server (NTRS)

Tiwari, S. N.; Manian, S. V. S.

1976-01-01

Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

Fast wave direct electron heating in advanced inductive and ITER baseline scenario discharges in DIII-D

DOE PAGES

Pinsker, R. I.; Austin, M. E.; Diem, S. J.; ...

2014-02-12

Fast Wave (FW) heating and electron cyclotron heating (ECH) are used in the DIII-D tokamak to study plasmas with low applied torque and dominant electron heating characteristic of burning plasmas. FW heating via direct electron damping has reached the 2.5 MW level in high performance ELMy H-mode plasmas. In Advanced Inductive (AI) plasmas, core FW heating was found to be comparable to that of ECH, consistent with the excellent first-pass absorption of FWs predicted by ray-tracing models at high electron beta. FW heating at the ~2 MW level to ELMy H-mode discharges in the ITER Baseline Scenario (IBS) showed unexpectedlymore » strong absorption of FW power by injected neutral beam (NB) ions, indicated by significant enhancement of the D-D neutron rate, while the intended absorption on core electrons appeared rather weak. As a result, the AI and IBS discharges are compared in an effort to identify the causes of the different response to FWs.« less

Fast wave direct electron heating in advanced inductive and ITER baseline scenario discharges in DIII-D

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

Pinsker, R. I.; Jackson, G. L.; Luce, T. C.

Fast Wave (FW) heating and electron cyclotron heating (ECH) are used in the DIII-D tokamak to study plasmas with low applied torque and dominant electron heating characteristic of burning plasmas. FW heating via direct electron damping has reached the 2.5 MW level in high performance ELMy H-mode plasmas. In Advanced Inductive (AI) plasmas, core FW heating was found to be comparable to that of ECH, consistent with the excellent first-pass absorption of FWs predicted by ray-tracing models at high electron beta. FW heating at the ∼2 MW level to ELMy H-mode discharges in the ITER Baseline Scenario (IBS) showed unexpectedlymore » strong absorption of FW power by injected neutral beam (NB) ions, indicated by significant enhancement of the D-D neutron rate, while the intended absorption on core electrons appeared rather weak. The AI and IBS discharges are compared in an effort to identify the causes of the different response to FWs.« less

Fast wave direct electron heating in advanced inductive and ITER baseline scenario discharges in DIII-D

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

Pinsker, R. I.; Austin, M. E.; Diem, S. J.

Fast Wave (FW) heating and electron cyclotron heating (ECH) are used in the DIII-D tokamak to study plasmas with low applied torque and dominant electron heating characteristic of burning plasmas. FW heating via direct electron damping has reached the 2.5 MW level in high performance ELMy H-mode plasmas. In Advanced Inductive (AI) plasmas, core FW heating was found to be comparable to that of ECH, consistent with the excellent first-pass absorption of FWs predicted by ray-tracing models at high electron beta. FW heating at the ~2 MW level to ELMy H-mode discharges in the ITER Baseline Scenario (IBS) showed unexpectedlymore » strong absorption of FW power by injected neutral beam (NB) ions, indicated by significant enhancement of the D-D neutron rate, while the intended absorption on core electrons appeared rather weak. As a result, the AI and IBS discharges are compared in an effort to identify the causes of the different response to FWs.« less

Cascade heat recovery with coproduct gas production

DOEpatents

Brown, William R.; Cassano, Anthony A.; Dunbobbin, Brian R.; Rao, Pradip; Erickson, Donald C.

1986-01-01

A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange.

Champagne Heat Pump

NASA Technical Reports Server (NTRS)

Jones, Jack A.

2004-01-01

The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

Liquid for absorption of solar heat

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

Nakamura, T.; Iwamoto, Y.; Kadotani, K.

A liquid for the absorption of solar heat, useful as an heat-absorbing medium in water heaters and heat collectors comprises: a dispersing medium selected from the group consisting of propylene glycol, mixture of propylene glycol with water, mixture of propylene glycol with water and glycerin, and mixture of glycerin with water, a dispersant selected from the group consisting of polyvinylpyrrolidone, caramel, and mixture of polyvinylpyrrolidone with caramel, and a powdered activated carbon as a black coloring material.

A generic analysis of energy use and solvent selection for CO2 separation from post-combustion flue gases

USGS Publications Warehouse

Lu, Y.; Chen, S.; Rostam-Abadi, M.

2008-01-01

A thermodynamic calculation was performed to determine the theoretical minimum energy used to separate CO2 from a coal combustion flue gas in a typical adsorption-desorption system. Under ideal conditions, the minimum energy required to separate CO2 from post-combustion flue gas and produce pure CO2 at 1 atmospheric pressure was only about 1183 kJ/kg CO2. This amount could double with the addition of the driving forces of mass and heat transfer and the adverse impacts of absorption heat release on adsorption capacity. Thermodynamic analyses were also performed for the aqueous amine-based absorption process. Two CO2 reaction mechanisms, the carbamate formation reaction with primary/secondary amines and the CO2 hydration reaction with tertiary amines, were included in the absorption reaction. The reaction heat, sensible heat, and stripping heat were all important to the total heat requirement. The heat use of an ideal tertiary amine amounted to 2786 kJ/kg, compared to 3211 kJ/kg for an ideal primary amine. The heat usage of an ideal amine was about 20% lower than that of commercially available amines. Optimizing the absorption process configuration could further reduce energy use. This is an abstract of a paper presented at the 2008 AIChE Spring National Meeting (New Orleans, LA 4/6-10/2008).

Full-time response of starch subjected to microwave heating.

PubMed

Fan, Daming; Wang, Liyun; Zhang, Nana; Xiong, Lei; Huang, Luelue; Zhao, Jianxin; Wang, Mingfu; Zhang, Hao

2017-06-21

The effect of non-ionizing microwave radiation on starch is due to a gelatinization temperature range that changes starch structure and properties. However, the changes in starch upon microwave heating are observable throughout the heating process. We compared the effects on starch heating by microwaves to the effects by rapid and regular conventional heating. Our results show that microwave heating promotes the rapid rearrangement of starch molecules at low temperatures; starch showed a stable dielectric response and a high dielectric constant. Microwave heating changed the Cole-Cole curve and the polarization of starch suspension at low temperatures. A marked transition at 2.45 GHz resulted in a double-polarization phenomenon. At temperatures below gelatinization, microwave-induced dielectric rearrangement and changes in the polarization characteristics of starch suspensions reduced the absorption properties; at temperatures above gelatinization, these characteristics became consistent with conventional heating. Throughout the heating process, microwaves change the electrical response and polarization characteristics of the starch at low temperatures, but on the macro level, there is no enhancement of the material's microwave absorption properties. In contrast, with the warming process, the starch exhibited a "blocking effect", and the absorption properties of the starch quickly returned to the level observed in conductive heating after gelatinization.

Physical aspects of heat generation/absorption in the second grade fluid flow due to Riga plate: Application of Cattaneo-Christov approach

NASA Astrophysics Data System (ADS)

Anjum, Aisha; Mir, N. A.; Farooq, M.; Javed, M.; Ahmad, S.; Malik, M. Y.; Alshomrani, A. S.

2018-06-01

The present article concentrates on thermal stratification in the flow of second grade fluid past a Riga plate with linear stretching towards a stagnation region. Heat transfer phenomenon is disclosed with heat generation/absorption. Riga plate is known as electromagnetic actuator which comprises of permanent magnets and alternating electrodes placed on a plane surface. Cattaneo-Christov heat flux model is implemented to analyze the features of heat transfer. This new heat flux model is the generalization of classical Fourier's law with the contribution of thermal relaxation time. For the first time heat generation/absorption effect is computed with non-Fourier's law of heat conduction (i.e., Cattaneo-Christov heat flux model). Transformations are used to obtain the governing non-linear ordinary differential equations. Approximate convergent solutions are developed for the non-dimensionalized governing problems. Physical features of velocity and temperature distributions are graphically analyzed corresponding to various parameters in 2D and 3D. It is noted that velocity field enhances with an increment of modified Hartman number while it reduces with increasing variable thickness parameter. Increment in modified heat generation parameter results in reduction of temperature field.

Cermet Coatings for Solar Stirling Space Power

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Raack, Taylor

2004-01-01

Cermet coatings, molecular mixtures of metal and ceramic are being considered for the heat inlet surface of a solar Stirling space power converter. This paper will discuss the solar absorption characteristics of as-deposited cermet coatings as well as the solar absorption characteristics of the coatings after heating. The role of diffusion and island formation, during the deposition process and during heating will also be discussed.

Spray generators for absorption refrigeration systems

DOEpatents

Sibley, Howard W.

1979-06-19

A spray generator for an absorption refrigeration system that includes a heat exchanger comprised of a multiplicity of variably spaced heat exchange tubes. The tubes are spaced close together near the top of the heat exchanger and spaced more widely apart near the bottom of the heat exchanger. Dilute absorbent solution is sprayed down through the heat exchanger. The close nesting of the tubes in the top portion of the heat exchanger retards liquid flow and aids heating of the solution. The wide spacing of the tubes in the lower section of the heat exchanger facilitate vapor flow out of the heat exchanger and eliminates liquid "blow-off". The top tubes are covered by a baffle to prevent the liquid solution from splashing out of the heat exchanger off of these top tubes.

Cascade heat recovery with coproduct gas production

DOEpatents

Brown, W.R.; Cassano, A.A.; Dunbobbin, B.R.; Rao, P.; Erickson, D.C.

1986-10-14

A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange. 4 figs.

Cattaneo-Christov double-diffusion theory for three-dimensional flow of viscoelastic nanofluid with the effect of heat generation/absorption

NASA Astrophysics Data System (ADS)

Hayat, Tasawar; Qayyum, Sajid; Shehzad, Sabir Ali; Alsaedi, Ahmed

2018-03-01

The present research article focuses on three-dimensional flow of viscoelastic(second grade) nanofluid in the presence of Cattaneo-Christov double-diffusion theory. Flow caused is due to stretching sheet. Characteristics of heat transfer are interpreted by considering the heat generation/absorption. Nanofluid theory comprises of Brownian motion and thermophoresis. Cattaneo-Christov double-diffusion theory is introduced in the energy and concentration expressions. Such diffusions are developed as a part of formulating the thermal and solutal relaxation times framework. Suitable variables are implemented for the conversion of partial differential systems into a sets of ordinary differential equations. The transformed expressions have been explored through homotopic algorithm. Behavior of sundry variables on the velocities, temperature and concentration are scrutinized graphically. Numerical values of skin friction coefficients are also calculated and examined. Here thermal field enhances for heat generation parameter while reverse situation is noticed for heat absorption parameter.

A Lithium Bromide Absorption Chiller with Cold Storage

DTIC Science & Technology

2011-01-15

Research ABSTRACT A LiBr -based absorption chiller can use waste heat or solar energy to produce useful space cooling for small buildings...high wa- ter consumption for heat rejection to the ambient. To alleviate these issues, a novel LiBr - based absorption chiller with cold storage is...proposed in this study. The cold storage includes tanks for storing liquid water and LiBr solution, associated piping, and control devices. The cold

Characterization by optical and magnetic spectroscopy of a synthesized SiO2 thin film used for radiation detector

NASA Astrophysics Data System (ADS)

Abdelaziz, T. D.; Ezz-Eldin, F. M.

2017-09-01

This work reports the synthesis and characterization of silica glass prepared by sol-gel procedure and finds out the effects of doses of gamma irradiation on the steps route of the heat-treated sample at 600 and 1100 °C. Combined characterizations of the glassy samples have been carried out by optical absorption and electron paramagnetic resonance. Also, FT infrared absorption spectra have been measured for both the heat-treated samples before and after gamma irradiation. Optical absorption spectra have identified an absorption band at 212-215 nm beside a broad band at 230-265 nm and the correlation of E' center with heat-treatment and gamma irradiation have been followed. FT infrared absorption spectra indicate the bands within near IR region representing the vibrational modes due to water, OH and SiOH within the wavenumber range 2500-3700 cm-1 are affected by heat treatment due to the elimination of organic residue and amount of OH and water. ESR investigations confirm the results obtained from optical and FTIR measurements. It is concluded from the collective data that sol-gel silica glass can serve as acceptable candidate for gamma-rays irradiator and gamma chamber dosimetry.

Absorption fluids data survey

NASA Astrophysics Data System (ADS)

Macriss, R. A.; Zawacki, T. S.

Development of improved data for the thermodynamic, transport and physical properties of absorption fluids were studied. A specific objective of this phase of the study is to compile, catalog and coarse screen the available US data of known absorption fluid systems and publish it as a first edition document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. The methodology and findings of the compilation, cataloguing and coarse screening of the available US data on absorption fluid properties and presents current status and future work on this project are summarized. Both in house file and literature searches were undertaken to obtain available US publications with pertinent physical, thermodynamic and transport properties data for absorption fluids. Cross checks of literature searches were also made, using available published bibliographies and literature review articles, to eliminate secondary sources for the data and include only original sources and manuscripts. The properties of these fluids relate to the liquid and/or vapor state, as encountered in normal operation of absorption equipment employing such fluids, and to the crystallization boundary of the liquid phase, where applicable. The actual data were systematically classified according to the type of fluid and property, as well as temperature, pressure and concentration ranges over which data were available. Data were sought for 14 different properties: Vapor-Liquid Equilibria, Crystallization Temperature, Corrosion Characteristics, Heat of Mixing, Liquid-Phase-Densities, Vapor-Liquid-Phase Enthalpies, Specific Heat, Stability, Viscosity, Mass Transfer Rate, Heat Transfer Rate, Thermal Conductivity, Flammability, and Toxicity.

Seasonal Solar Thermal Absorption Energy Storage Development.

PubMed

Daguenet-Frick, Xavier; Gantenbein, Paul; Rommel, Mathias; Fumey, Benjamin; Weber, Robert; Gooneseker, Kanishka; Williamson, Tommy

2015-01-01

This article describes a thermochemical seasonal storage with emphasis on the development of a reaction zone for an absorption/desorption unit. The heat and mass exchanges are modelled and the design of a suitable reaction zone is explained. A tube bundle concept is retained for the heat and mass exchangers and the units are manufactured and commissioned. Furthermore, experimental results of both absorption and desorption processes are presented and the exchanged power is compared to the results of the simulations.

Carbon Dioxide Absorption Heat Pump

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor)

2002-01-01

A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

Triple loop heat exchanger for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

Nanoplasmon-enabled macroscopic thermal management

PubMed Central

Jonsson, Gustav Edman; Miljkovic, Vladimir; Dmitriev, Alexandre

2014-01-01

In numerous applications of energy harvesting via transformation of light into heat the focus recently shifted towards highly absorptive nanoplasmonic materials. It is currently established that noble metals-based absorptive plasmonic platforms deliver significant light-capturing capability and can be viewed as super-absorbers of optical radiation. Naturally, approaches to the direct experimental probing of macroscopic temperature increase resulting from these absorbers are welcomed. Here we derive a general quantitative method of characterizing heat-generating properties of optically absorptive layers via macroscopic thermal imaging. We further monitor macroscopic areas that are homogeneously heated by several degrees with nanostructures that occupy a mere 8% of the surface, leaving it essentially transparent and evidencing significant heat generation capability of nanoplasmon-enabled light capture. This has a direct bearing to a large number of applications where thermal management is crucial. PMID:24870613

Significant consequences of heat generation/absorption and homogeneous-heterogeneous reactions in second grade fluid due to rotating disk

NASA Astrophysics Data System (ADS)

Hayat, Tasawar; Qayyum, Sumaira; Alsaedi, Ahmed; Ahmad, Bashir

2018-03-01

Flow of second grade fluid by a rotating disk with heat and mass transfer is discussed. Additional effects of heat generation/absorption are also analyzed. Flow is also subjected to homogeneous-heterogeneous reactions. The convergence of computed solution is assured through appropriate choices of initial guesses and auxiliary parameters. Investigation is made for the effects of involved parameters on velocities (radial, axial, tangential), temperature and concentration. Skin friction and Nusselt number are also analyzed. Graphical results depict that an increase in viscoelastic parameter enhances the axial, radial and tangential velocities. Opposite behavior of temperature is observed for larger values of viscoelastic and heat generation/absorption parameters. Concentration profile is increasing function of Schmidt number, viscoelastic parameter and heterogeneous reaction parameter. Magnitude of skin friction and Nusselt number are enhanced for larger viscoelastic parameter.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

Heat generation and light scattering of green fluorescent protein-like pigments in coral tissue

NASA Astrophysics Data System (ADS)

Lyndby, Niclas H.; Kühl, Michael; Wangpraseurt, Daniel

2016-05-01

Green fluorescent protein (GFP)-like pigments have been proposed to have beneficial effects on coral photobiology. Here, we investigated the relationships between green fluorescence, coral heating and tissue optics for the massive coral Dipsastraea sp. (previously Favia sp.). We used microsensors to measure tissue scalar irradiance and temperature along with hyperspectral imaging and combined imaging of variable chlorophyll fluorescence and green fluorescence. Green fluorescence correlated positively with coral heating and scalar irradiance enhancement at the tissue surface. Coral tissue heating saturated for maximal levels of green fluorescence. The action spectrum of coral surface heating revealed that heating was highest under red (peaking at 680 nm) irradiance. Scalar irradiance enhancement in coral tissue was highest when illuminated with blue light, but up to 62% (for the case of highest green fluorescence) of this photon enhancement was due to green fluorescence emission. We suggest that GFP-like pigments scatter the incident radiation, which enhances light absorption and heating of the coral. However, heating saturates, because intense light scattering reduces the vertical penetration depth through the tissue eventually leading to reduced light absorption at high fluorescent pigment density. We conclude that fluorescent pigments can have a central role in modulating coral light absorption and heating.

Effect of heat treatment on absorption and fluorescence properties of PbS-doped silica optical fibre

NASA Astrophysics Data System (ADS)

Qin, Fu; Dong, Yanhua; Wen, Jianxiang; Pang, Fufei; Luo, Yanhua; Peng, Gang-Ding; Chen, Zhenyi; Wang, Tingyun

2017-02-01

The effect of heat treatment on the optical properties of a PbS-doped silica optical fibre was investigated. The experimental results showed that the absorption peak of the fibre red shifted from 1032 to 1133 nm when the heat treatment temperatures were carried out at 900, 950, 1000, and 1100 °C for 1 h, respectively. At the same time, when the heat treatment at 900 °C was carried out for 2, 5, 10, 20, and 40 h, the absorption spectra of the fibre showed a red shift from 1074 to 1143 nm. In addition, the intensity of the absorption peak increased from 0.258 to 1.384 dB/m and the full width at half maximum (FWHM) became narrower (from 130 to 50 nm) as the heat treatment proceeded. Moreover, the photoluminescence (PL) intensity in the wavelength range of 1100-1500 nm decreased with an increase in the heat treatment temperature. The theoretical analysis, using an effective mass method, showed that the effective band gap energy and average size of the lead sulphide (PbS) quantum dots (QDs) in the silica fibre core varied from 1.199 to 1.083 eV and from 4.28 to 4.81 nm, respectively. The results indicate that the size of the PbS QDs present in the silica fibre core could be controlled by a proper heat treatment, which is of great interest in optical fibre amplifiers and other fibre optic devices.

Ultraviolet absorption spectra of shock-heated carbon dioxide and water between 900 and 3050 K

NASA Astrophysics Data System (ADS)

Schulz, C.; Koch, J. D.; Davidson, D. F.; Jeffries, J. B.; Hanson, R. K.

2002-03-01

Spectrally resolved UV absorption cross-sections between 190 and 320 nm were measured in shock-heated CO 2 between 880 and 3050 K and H 2O between 1230 and 2860 K. Absorption spectra were acquired with 10 μs time resolution using a unique kinetic spectrograph, thereby enabling comparisons with time-dependent chemical kinetic modeling of post-shock thermal decomposition and chemical reactions. Although room temperature CO 2 is transparent (σ<10 -22 cm2) at wavelengths longer than 200 nm, hot CO 2 has significant absorption (σ>10 -20 cm2) extending to wavelengths longer than 300 nm. The temperature dependence of CO 2 absorption strongly suggests sharply increased transition probabilities from excited vibrational levels.

Direct fired absorption machine flue gas recuperator

DOEpatents

Reimann, Robert C.; Root, Richard A.

1985-01-01

A recuperator which recovers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine. The recuperator includes a housing with liquid flowing therethrough, the liquid being in direct contact with the combustion gas for increasing the effectiveness of the heat transfer between the gas and the liquid.

Laser-heated thruster

NASA Technical Reports Server (NTRS)

Kemp, N. H.; Lewis, P. F.

1980-01-01

The development of a computer program for the design of the thrust chamber for a CW laser heated thruster was examined. Hydrodgen was employed as the propellant gas and high temperature absorber. The laser absorption coefficient of the mixture/laser radiation combination is given in temperature and species densities. Radiative and absorptive properties are given to determine radiation from such gas mixtures. A computer code for calculating the axisymmetric channel flow of a gas mixture in chemical equilibrium, and laser energy absorption and convective and radiative heating is described. It is concluded that: (1) small amounts of cesium seed substantially increase the absorption coefficient of hydrogen; (2) cesium is a strong radiator and contributes greatly to radiation of cesium seeded hydrogen; (3) water vapor is a poor absorber; and (4) for 5.3mcm radiation, both H2O/CO and NO/CO seeded hydrogen mixtures are good absorbers.

Effects of heat induced by two-photon absorption and free-carrier absorption in silicon-on-insulator nanowaveguides operating as all-optical wavelength converters.

PubMed

Abdollahi, Siamak; Moravvej-Farshi, Mohammad Kazem

2009-05-01

We propose a new numerical model to analyze heat induced by two-photon absorption and free-carrier absorption, while high intensity optical pulses propagate along silicon-on-insulator (SOI) nanowaveguides (NWGs). Using this model, we demonstrate that such induced heat causes a shift in the amount of wavelength conversion and hence deteriorates the converter output characteristics for pulses in the picosecond regime. The wavelength shift induced by a pulse with maximum input intensity and full width at half-maximum of I(max)=1.5x10(10) W x cm(-2) and T(FWHM)=30 ps, propagating along a SOI NWG with an effective cross-sectional area of a(eff)=0.15 microm(2), is shown to be Delta lambda(s) approximately 8 pm. We also demonstrate that such a shift can be compensated by tuning the pump intensity down by approximately 6.33%.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, David A.; Keller, Richard A.

1984-01-01

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10.sup.-5 cm.sup.-1 can then be determined in the presence of background absorptions in excess of 10.sup.-3 cm.sup.-1. In addition, the smallest absorption measured with the instant apparatus and method is about 5.times. 10.sup.-6 cm.sup.-1.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1982-06-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10/sup -5/ cm/sup -1/ can then be determined in the presence of background absorptions in excess of 10/sup -3/ cm/sup -1/. In addition, the smallest absorption measured with the instant apparatus and method is about 5 x 10/sup -6/ cm/sup -1/.

Heat exchanger bypass system for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

Preparation of gold nanoparticle aggregates and their photothermal heating property.

PubMed

Kim, Jun-Hyun; Lavin, Brian W

2011-01-01

This report describes simple synthetic strategies to prepare partially aggregated gold nanoparticles (GNPs) and their ability to produce photothermally-induced heating of an aqueous medium upon exposure to broadband light. The formation of various GNPs and their aggregates were accomplished in the absence of surfactants at room temperature. The morphologies, structures, and absorption properties of these GNPs were carefully characterized. Given that the resulting GNPs possessing strong and wide absorption bands fall in the most intense solar radiation spectrum, the photothermally-induced heating of water was examined in the presence of the GNPs via irradiation with a solar simulator (i.e., 100 mW/cm2; 1-sun condition). Our GNPs exhibited a slightly greater increase in the water temperature (3-4 degrees C) than that of conventional citrate-stabilized GNPs. This superior photothermal heating property of our GNPs directly indicated that the intense and broad absorption band effectively improved the conversion of highly absorbed photon energy into heat.

Plasmonic near-touching titanium oxide nanoparticles to realize solar energy harvesting and effective local heating.

PubMed

Yan, Jiahao; Liu, Pu; Ma, Churong; Lin, Zhaoyong; Yang, Guowei

2016-04-28

Through the excitation of plasmon resonance, the energy of plasmonic nanoparticles either reradiates through light scattering or decays into energetic electrons (absorption). The plasmon-induced absorption can greatly enhance the efficiency of solar energy harvesting, local heating, photodetection and photocatalysis. Here, we demonstrate that heavily self-doped titanium oxide nanoparticles (TiO1.67 analogue arising from oxygen vacancies in rutile TiO2) with the plasmon resonance dominated by an interband transition shows strong absorption to build a broadband perfect absorber in the wavelength range from 300 to 2000 nm covering the solar irradiation spectrum completely. The absorptivity of the fabricated array is greater than 90% in the whole spectral range. And the broadband and strong absorption is due to the plasmon hybridization and hot spot generation from near-touching TiO1.67 nanoparticles with different sizes. What is more, the local heating of a TiO1.67 nanoparticle layer is fast and effective. The temperature increases quickly from 30 °C to 80 °C within 200 seconds. This local heating can realize rapid solar-enabled evaporation which can find applications in large-scale distillation and seawater desalination. These findings actually open a pathway for applications of these newly developed plasmonic materials in the energy and environment fields.

Thermal energy transformer

NASA Technical Reports Server (NTRS)

Berdahl, C. M.; Thiele, C. L. (Inventor)

1979-01-01

For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

How gas cools (or, apples can fall up)

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

Not Available

1987-01-01

This primer on gas cooling systems explains the basics of heat exchange within a refrigeration system, the principle of reverse-cycle refrigeration, and how a gas-engine-driven heat pump can provide cooling, additional winter heating capacity, and hot water year-round. Gas cooling equipment available or under development include natural gas chillers, engine-driven chillers, and absorption chillers. In cogeneration systems, heat recovered from an engine's exhaust and coolant may be used in an absorption chiller to provide air-conditioning. Gas desiccant cooling systems may be used in buildings and businesses that are sensitive to high humidity levels.

The Radiative Heat Transfer Properties of Molten Salts and Their Relevance to the Design of Advanced Reactors

NASA Astrophysics Data System (ADS)

Chaleff, Ethan Solomon

Molten salts, such as the fluoride salt eutectic LiF-NaF-KF (FLiNaK) or the transition metal fluoride salt KF-ZrF4, have been proposed as coolants for numerous advanced reactor concepts. These reactors are designed to operate at high temperatures where radiative heat transfer may play a significant role. If this is the case, the radiative heat transfer properties of the salt coolants are required to be known for heat transfer calculations to be performed accurately. Chapter 1 describes the existing literature and experimental efforts pertaining to radiative heat transfer in molten salts. The physics governing photon absorption by halide salts is discussed first, followed by a more specific description of experimental results pertaining to salts of interest. The phonon absorption edge in LiF-based salts such as FLiNaK is estimated and the technique described for potential use in other salts. A description is given of various spectral measurement techniques which might plausibly be employed in the present effort, as well as an argument for the use of integral techniques. Chapter 2 discusses the mathematical treatments required to approximate and solve for the radiative flux in participating materials. The differential approximation and the exact solutions to the radiative flux are examined, and methods are given to solve radiative and energy equations simultaneously. A coupled solution is used to examine radiative heat transfer to molten salt coolants. A map is generated of pipe diameters, wall temperatures, and average absorption coefficients where radiative heat transfer will increase expected heat transfer by more than 10% compared to convective methods alone. Chapter 3 presents the design and analysis of the Integral Radiative Absorption Chamber (IRAC). The IRAC employs an integral technique for the measurement of the entire electromagnetic spectrum, negating some of the challenges associated with the methods discussed in Chapter 1 at the loss of spectral information. The IRAC design is validated by modeling the experiment in Fluent which shows that the IRAC should be capable of measuring absorption coefficients within 10%. Chapter 4 contains a parallel effort to experimental techniques, whereby information on absorption in salts is pursued using the Density Functional Theory code VASP. Photon-electron interactions are studied in pure salts such as LiF and are shown to be broadly transparent. Transition metal Fluoride salts such as KF-ZrF4 are shown to be broadly opaque. The addition of small amounts of transition metal impurities is studied by insertion of Chromium into the salt mixtures, which causes otherwise transparent salts to exhibit absorption coefficients significant to heat transfer. The spectral absorption coefficient for FLiNaK with Chromium is presented as is the average absorption coefficient as a function of impurity concentration. Chapter 5 discusses experimental efforts undertaken at The Ohio State University. Challenges with the constructed experimental apparatus are discussed and suggestions for future improvement on the technique are included. Finally, Chapter 6 contains broad conclusions pertaining to radiative transfer in advanced reactors.

Ultrafast X-Ray Absorption Spectroscopy of Isochorically Heated Warm Dense Matter

NASA Astrophysics Data System (ADS)

Engelhorn, Kyle Craig

This dissertation will present a series of new tools, together with new techniques, focused on the understanding of warm and dense matter. We report on the development of a high time resolution and high detection efficiency x-ray camera. The camera is integrated with a short pulse laser and an x-ray beamline at the Advanced Light Source synchrotron. This provides an instrument for single shot, broadband x-ray absorption spectroscopy of warm and dense matter with 2 picosecond time resolution. Warm and dense matter is created by isochorically heating samples of known density with an ultrafast optical laser pulse, and X-ray absorption spectroscopy probes the unoccupied electronic density of states before the onset of hydrodynamic expansion and electron-ion equilibrium is reached. Measured spectra from a variety of materials are compared with first principle molecular dynamics and density functional theory calculations. In heated silicon dioxide spectra, two novel pre-edge features are observed, a peak below the band gap and absorption within the band gap, while a reduction was observed in the features above the edge. From consideration of the calculated spectra, the peak below the gap is attributed to valence electrons that have been promoted to the conduction band, the absorption within the gap is attributed to broken Si-O bonds, and the reduction above the edge is attributed to an elevated ionic temperature. In heated copper spectra, a time-dependent shift and broadening of the absorption edge are observed, consistent with and elevated electron temperature. The temporal evolution of the electronic temperature is accurately determined by fitting the measured spectra with calculated spectra. The electron-ion equilibration is studied with a two-temperature model. In heated nickel spectra, a shift of the absorption edge is observed. This shift is found to be inconsistent with calculated spectra and independent of incident laser fluence. A shift of the chemical potential is applied to the calculated spectra to obtain satisfactory agreement with measured spectra.

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

CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar

In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser.more » The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the cycle is recovery of the solution heat energy exiting the desorber by process water (a process-solution heat exchanger ) rather than the absorber exiting solution (the conventional solution heat exchanger ). This approach has enabled heating the process water from an inlet temperature of 15 C to 57 C (conforming to the DOE water heater test standard) and interfacing the process water with absorbent on the opposite side of a single metal sheet encompassing the absorber, process-solution heat exchanger, and desorber. The system under development has a 3.2 kW water heating capacity and a target thermal coefficient of performance (COP) of 1.6.« less

Effect of air velocity and direction for indirect evaporative cooling in tropical area

NASA Astrophysics Data System (ADS)

Ayodha Ajiwiguna, Tri; Nugraha Rismi, Fadhlin; Ramdlan Kirom, Mukhammad

2017-06-01

In this research, experimental study of heat absorption rate caused by indirect evaporative cooling is performed by varying the velocity and direction of air. The ambient is at average temperature and relative humidity of 28.7 °C and 78% respectively. The experiment is conducted by attaching wet medium on the top of material reference plate with the dimension of 14 x 8 cm with 5 mm thickness. To get evaporative cooling effect, the air flow is directed to the wet medium with velocity from 1.6 m/s to 3.4 m/s with the increment of 0.2 m/s. The direction of air is set 0° (parallel), 45° (inclined), and 90° (perpendicular) to the wet medium surface. While the experiment is being performed, the air temperature, top and bottom of plate temperature are measured simultaneously after steady state condition is established. Based on the measurement result, heat absorption is calculated by analysing the heat conduction on the material reference. The result shows that the heat absorption rate is increased by higher velocity. Perpendicular direction of air flow results the highest cooling capacity compared with other direction. The maximum heat absorption rate is achieved at 13.9 Watt with 3.4 m/s velocity and perpendicular direction of air.

Simulation of a 20-ton LiBr/H{sub 2}O absorption cooling system

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

Wardono, B.; Nelson, R.M.

The possibility of using solar energy as the main heat input for cooling systems has led to several studies of available cooling technologies that use solar energy. The results show that double-effect absorption cooling systems give relatively high performance. To further study absorption cooling systems, a computer code was developed for a double-effect lithium bromide/water (LiBr/H{sub 2}O) absorption system. To evaluate the performance, two objective functions were developed including the coefficient of performance (COP) and the system cost. Based on the system cost, an optimization to find the minimum cost was performed to determine the nominal heat transfer areas ofmore » each heat exchanger. The nominal values of other system variables, such as the mass flow rates and inlet temperatures of the hot water, cooling water, and chilled water, are specified as commonly used values for commercial machines. The results of the optimization show that there are optimum heat transfer areas. In this study, hot water is used as the main energy input. Using a constant load of 20 tons cooling capacity, the effects of various variables including the heat transfer ares, mass flow rates, and inlet temperatures of hot water, cooling water, and chilled water are presented.« less

Radiative energy balance of the Venus mesosphere

NASA Astrophysics Data System (ADS)

Haus, R.; Goering, H.

1990-03-01

An accurate radiative transfer model for line-by-line gaseous absorption, as well as for cloud absorption and multiple scattering, is used in the present calculation of solar heating and thermal cooling rates for standard temperature profiles and temperatures yielded by the Venera 15 Fourier Spectrometer Experiment. A strong dependency is noted for heating and cooling rates on cloud-structure variations. The Venus mesosphere is characterized by main cloud-cover heating and overlying-haze cooling. These results are applicable to Venus atmosphere dynamical models.

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

A reaction cell with sample laser heating for in situ soft X-ray absorption spectroscopy studies under environmental conditions.

PubMed

Escudero, Carlos; Jiang, Peng; Pach, Elzbieta; Borondics, Ferenc; West, Mark W; Tuxen, Anders; Chintapalli, Mahati; Carenco, Sophie; Guo, Jinghua; Salmeron, Miquel

2013-05-01

A miniature (1 ml volume) reaction cell with transparent X-ray windows and laser heating of the sample has been designed to conduct X-ray absorption spectroscopy studies of materials in the presence of gases at atmospheric pressures. Heating by laser solves the problems associated with the presence of reactive gases interacting with hot filaments used in resistive heating methods. It also facilitates collection of a small total electron yield signal by eliminating interference with heating current leakage and ground loops. The excellent operation of the cell is demonstrated with examples of CO and H2 Fischer-Tropsch reactions on Co nanoparticles.

Determination of trace and minor elements in alloys by atomic-absorption spectroscopy using an induction-heated graphite-well furnace as atom source-II.

PubMed

Ashy, M A; Headridge, J B; Sowerbutts, A

1974-06-01

Results are presented for the atomic-absorption spectrophotometric determination of zinc in aluminium and aluminium-silicon alloys, and aluminium, antimony and tin in steels, by means of solid samples dropped into an induction-heated graphite-well furnace to produce the atomic vapour.

Organic absorption gas-fired residential heat pump

NASA Astrophysics Data System (ADS)

Murphy, K. P.

The development program of a system utilizing a new absorption pair, R133a (CF3CH2Cl) as the refigerant, and ETFE (ethyletra-hydrofurfury lether) as the absorber fluid, is described. A diagram of the basic configuration is shown. The cooling mode and the heating mode are discussed. Six units of an early hardware design were constructed and tested. Two of these units were placed in home heating service during the 1980-81 season. A market evaluation of the business potential of the absorption system was made, identifying location and size of the likely market for such a system. A performance simulation analysis was performed for seven cities in the US. From these, general characteristics of the areas having the greatest performance benefits were established.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

NASA Astrophysics Data System (ADS)

Asriza, Ristika O.; Arcana, I. Made

2015-09-01

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

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

Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of themore » absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.« less

Investigating cloud absorption effects: Global absorption properties of black carbon, tar balls, and soil dust in clouds and aerosols

NASA Astrophysics Data System (ADS)

Jacobson, Mark Z.

2012-03-01

This study examines modeled properties of black carbon (BC), tar ball (TB), and soil dust (SD) absorption within clouds and aerosols to understand better Cloud Absorption Effects I and II, which are defined as the effects on cloud heating of absorbing inclusions in hydrometeor particles and of absorbing aerosol particles interstitially between hydrometeor particles at their actual relative humidity (RH), respectively. The globally and annually averaged modeled 550 nm aerosol mass absorption coefficient (AMAC) of externally mixed BC was 6.72 (6.3-7.3) m2/g, within the laboratory range (6.3-8.7 m2/g). The global AMAC of internally mixed (IM) BC was 16.2 (13.9-18.2) m2/g, less than the measured maximum at 100% RH (23 m2/g). The resulting AMAC amplification factor due to internal mixing was 2.41 (2-2.9), with highest values in high RH regions. The global 650 nm hydrometeor mass absorption coefficient (HMAC) due to BC inclusions was 17.7 (10.6-19) m2/g, ˜9.3% higher than that of the IM-AMAC. The 650 nm HMACs of TBs and SD were half and 1/190th, respectively, that of BC. Modeled aerosol absorption optical depths were consistent with data. In column tests, BC inclusions in low and mid clouds (CAE I) gave column-integrated BC heating rates ˜200% and 235%, respectively, those of interstitial BC at the actual cloud RH (CAE II), which itself gave heating rates ˜120% and ˜130%, respectively, those of interstitial BC at the clear-sky RH. Globally, cloud optical depth increased then decreased with increasing aerosol optical depth, consistent with boomerang curves from satellite studies. Thus, CAEs, which are largely ignored, heat clouds significantly.

How do Greenhouse Gases Warm the Ocean? Investigation of the Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes.

NASA Astrophysics Data System (ADS)

Wong, E.; Minnett, P. J.

2016-12-01

There is much evidence that the ocean is heating due to an increase in concentrations of greenhouse gases (GHG) in the atmosphere from human activities. GHGs absorbs infrared (IR) radiation and re-emits the radiation back to the ocean's surface which is subsequently absorbed resulting in a rise in the ocean heat content. However, the incoming longwave radiation, LWin, is absorbed within the top micrometers of the ocean's surface, where the thermal skin layer (TSL) exists and does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of IR radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that since heat lost through the air-sea interface is controlled by the TSL, which is directly influenced by the absorption and emission of IR radiation, the heat flow through the TSL adjusts to maintain the surface heat loss, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in LWin and analyzing retrieved TSL vertical profiles from a shipboard IR spectrometer from two research cruises. The data is limited to night-time, no precipitation and low winds of < 2 m/s to remove effects of solar radiation, wind-driven shear and possibilities of TSL disruption. The results show independence between the turbulent fluxes and radiative fluxes which rules out the immediate release of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation. Instead, we observe the surplus energy, from absorbing increasing levels of LWin, adjusts the curvature of the TSL such that there is a lower gradient at the interface between the TSL and the mixed layer. The release of heat stored within the mixed layer is therefore hindered while the additional energy within the TSL is cycled back into the atmosphere. This results in heat beneath the TSL, which is a product of the absorption of solar radiation during the day, to be retained and cause an increase in upper ocean heat content.

Absorption Cross-Sections of Sodium Diatomic Molecules

NASA Technical Reports Server (NTRS)

Fong, Zeng-Shevan

1985-01-01

The absorption cross sections of sodium dimers were studied using a heat pipe over operating in the non-heat-pipe mode. Three wavelength regions were observed. They are in the red, the green-blue, and the near ultraviolet regions. The absorption cross section depends on the wavelength of the incident light. Representative peak values for the v"=0 progression in the red and green-blue regions are 2.59 A sup 2 (average value) and 11.77 A sup 2 (T sub ave=624 K). The value for the C greater than X transitions is several tenths A sup 2. The cross sections were measured from absorption spectra taken as a function of temperature.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1984-05-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect have been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical path length of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10[sup [minus]5] cm[sup [minus]1] can then be determined in the presence of background absorptions in excess of 10[sup [minus]3] cm[sup [minus]1]. In addition, the smallest absorption measured with the instant apparatus and method is about 5 [times] 10[sup [minus]6] cm[sup [minus]1]. 6 figs.

Viable, lyophilized lactobacilli do not increase iron absorption from a lactic acid-fermented meal in healthy young women, and no iron absorption occurs in the distal intestine.

PubMed

Bering, Stine; Sjøltov, Laila; Wrisberg, Seema S; Berggren, Anna; Alenfall, Jan; Jensen, Mikael; Højgaard, Liselotte; Tetens, Inge; Bukhave, Klaus

2007-11-01

Lactic acid-fermented foods have been shown to increase Fe absorption in human subjects, possibly by lowering pH, activation of phytases, production of organic acids, or by the viable lactic acid bacteria. In this study the effect of a heat-inactivated lactic acid-fermented oat gruel with and without added viable, lyophilized Lactobacillus plantarum 299v on non-haem Fe absorption was investigated. Furthermore, Fe absorption in the distal intestine was determined. In a randomized, double-blinded crossover trial eighteen healthy young women aged 22 (SD 3) years with low Fe status (serum ferritin < 30 microg/l) were served the two test gruels, extrinsically labelled with 59Fe and served with two enterocoated capsules (containing 55Fe(II) and 55Fe(III), respectively) designed to disintegrate in the ileum. The meals were consumed on two consecutive days, e.g. in the order AA followed by BB in a second period. Non-haem Fe absorption was determined from 59Fe whole-body retention and isotope activities in blood samples. The concentrations of Fe, lactate, phytate, and polyphenols, and the pH were similar in the heat-inactivated lactic acid-fermented oat gruels with and without added L. plantarum 299v, and no difference in Fe absorption was observed between the test gruels (1.4 and 1.3%, respectively). Furthermore, no absorption of Fe in the distal intestine was observed. In conclusion, addition of viable, lyophilized lactobacillus to a heat-inactivated lactic acid-fermented oat gruel does not affect Fe absorption, and no absorption seems to occur in the distal part of the intestine from low Fe bioavailability meals in these women.

Site dependent factors affecting the economic feasibility of solar powered absorption cooling

NASA Technical Reports Server (NTRS)

Bartlett, J. C.

1978-01-01

A procedure was developed to evaluate the cost effectiveness of combining an absorption cycle chiller with a solar energy system. A basic assumption of the procedure is that a solar energy system exists for meeting the heating load of the building, and that the building must be cooled. The decision to be made is to either cool the building with a conventional vapor compression cycle chiller or to use the existing solar energy system to provide a heat input to the absorption chiller. Two methods of meeting the cooling load not supplied by solar energy were considered. In the first method, heat is supplied to the absorption chiller by a boiler using fossil fuel. In the second method, the load not met by solar energy is net by a conventional vapor compression chiller. In addition, the procedure can consider waste heat as another form of auxiliary energy. Commercial applications of solar cooling with an absorption chiller were found to be more cost effective than the residential applications. In general, it was found that the larger the chiller, the more economically feasible it would be. Also, it was found that a conventional vapor compression chiller is a viable alternative for the auxiliary cooling source, especially for the larger chillers. The results of the analysis gives a relative rating of the sites considered as to their economic feasibility of solar cooling.

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

PubMed

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

2008-09-01

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

High Efficiency Water Heating Technology Development Final Report, Part II: CO 2 and Absorption-Based Residential Heat Pump Water Heater Development

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

Gluesenkamp, Kyle R.; Abdelaziz, Omar; Patel, Viral K.

2017-05-01

The two objectives of this project were to 1.demonstrate an affordable path to an ENERGY STAR qualified electric heat pump water heater (HPWH) based on low-global warming potential (GWP) CO 2 refrigerant, and 2.demonstrate an affordable path to a gas-fired absorption-based heat pump water heater with a gas energy factor (EF) greater than 1.0. The first objective has been met, and the project has identified a promising low-cost option capable of meeting the second objective. This report documents the process followed and results obtained in addressing these objectives.

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.

Milestone Report:3.2.2.26 Appliances, HVAC & Water Heating R&D-Select Sorption Technology

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

Ally, Moonis Raza

The purpose of this report is to select a sorption technology based on recent work completed on characterizing working pairs for both absorption and adsorption technologies based on Global Warming Potential (GWP) of less than 100 (relative to carbon dioxide, 100-year atmospheric life span) and zero Ozone Depletion Potential (ODP). From a total of eighty-three potential working pairs (absorption technology), there were only two candidate working pairs for the absorption technology, and 8 potential working pairs for adsorption technology. After screening these ten potential candidates on the basis of sizes of the desorber, absorber/adsorber, evaporator, condenser, and rectifier (where applicable),more » the ORNL-Georgia Tech study concluded that best working pairs are NH3-H2O for the most compact system in terms of heat transfer equipment surface area, and NH3-LiNO3 and MeOH-[mmin][DMP] where efficiency is most important. Based on a single-stage absorption and adsorption modeling using the Engineering Equation Solver (EES), the performance of both sorption systems was evaluated from known heat transfer correlations, and thermos-physical properties. Based on these results, the technology chosen is absorption technology. The selected technology is absorption for the reasons cited in Section 4.« less

Heat transfer capability of solar radiation in colored roof and influence on room thermal comfort

NASA Astrophysics Data System (ADS)

Syuhada, Ahmad; Maulana, Muhammad Ilham

2018-02-01

Colored zinc is the most widely used by people in Indonesia as the roof of the building. Each color has different heat absorption capability, the higher the absorption capacity of a roof will cause high room temperature. A high temperature in the room will cause the room is not thermally comfortable for activity. Lack of public knowledge about the ability of each color to absorb heat can cause errors in choosing the color of the roof of the building so that it becomes uncomfortable regarding thermal comfort. This study examined how big the ability of each color in influencing the heat absorption on the roof of the zinc. The purpose of this study is to examine which colors are the lowest to absorb radiation heat. This research used theexperimental method. Data collected by measuring the temperature of the environment above and below the colored tin roof, starting at 11:00 am until 15:00 pm. The zinc roofs tested in this study are zinc black, red zinc, green zinc, blue zinc, brown zinc, maroon zinc, orange zinc, zinc gray, zinc color chrome and zinc white color. The study results show that black and blackish colors will absorb more heat than other colors. While the color white or close to whitish color will absorb a slight heat.

Heat and Mass Transfer of Ammonia Gas Absorption into Falling Liquid Film on a Horizontal Tube

NASA Astrophysics Data System (ADS)

Inoue, Norihiro; Yabuuchi, Hironori; Goto, Masao; Koyama, Shigeru

Heat and mass transfer coefficients during ammonia gas absorption into a falling liquid film formed by distilled water on a horizontal tube were obtained experimentally. The test absorber consists of 200 mm i.d., 600 mm long stainless steel shell, a 1 7.3 mm o.d., 14.9 mm i.d. stainless steel test tube with 600 mm working length mounted along the axis of shell, and a 12.7 mm o.d. pipe manifold of supplying the absorbent. In this paper, it was clear that heat and mass transfer coefficient could be enhanced by increasing the flow rate of absorbent and temperature difference between inlet absorbent and ammonia gas, also heat driven by the temperature difference have an effect on heat transfer of the fa1ling liquid film and mass transfer of vapor side. And the new correlation of heat transfer in dimensionless form was proposed by the temperature difference which was considered heat driven of vapor and liquid film side using a interface temperature of vapor and liquid phase. The new correlations of mass transfer on a interface of vapor and liquid phase in dimensionless form were proposed by using effect factors could be suppose from absorption phenomena.

Measurement and analysis of x-ray absorption in Al and MgF2 plasmas heated by Z-pinch radiation.

PubMed

Rochau, Gregory A; Bailey, J E; Macfarlane, J J

2005-12-01

High-power Z pinches on Sandia National Laboratories' Z facility can be used in a variety of experiments to radiatively heat samples placed some distance away from the Z-pinch plasma. In such experiments, the heating radiation spectrum is influenced by both the Z-pinch emission and the re-emission of radiation from the high-Z surfaces that make up the Z-pinch diode. To test the understanding of the amplitude and spectral distribution of the heating radiation, thin foils containing both Al and MgF2 were heated by a 100-130 TW Z pinch. The heating of these samples was studied through the ionization distribution in each material as measured by x-ray absorption spectra. The resulting plasma conditions are inferred from a least-squares comparison between the measured spectra and calculations of the Al and Mg 1s-->2p absorption over a large range of temperatures and densities. These plasma conditions are then compared to radiation-hydrodynamics simulations of the sample dynamics and are found to agree within 1sigma to the best-fit conditions. This agreement indicates that both the driving radiation spectrum and the heating of the Al and MgF2 samples is understood within the accuracy of the spectroscopic method.

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

Isfahani, RN; Moghaddam, S

An experimental study on absorption characteristics of water vapor into a thin lithium bromide (LiBr) solution flow is presented. The LiBr solution flow is constrained between a superhydrophobic vapor permeable wall and a solid surface that removes the heat of absorption. As opposed to conventional falling film absorbers, in this configuration, the solution film thickness and velocity can be controlled independently to enhance the absorption rate. The effects of water vapor pressure, cooling surface temperature, solution film thickness, and solution flow velocity on the absorption rate are studied. An absorption rate of approximately 0.006 kg/m(2) s was measured at amore » LiBr solution channel thickness and flow velocity of 100 mu m and 5 mm/s, respectively. The absorption rate increased linearly with the water vapor driving potential at the test conditions of this study. It was demonstrated that decreasing the solution film thickness and increasing the solution velocity enhance the absorption rate. The high absorption rate and the inherently compact form of the proposed,absorber facilitate development of compact small-scale waste heat or solar-thermal driven cooling systems. Published by Elsevier Ltd.« less

Unsteady Sisko magneto-nanofluid flow with heat absorption and temperature dependent thermal conductivity: A 3D numerical study

NASA Astrophysics Data System (ADS)

Khan, Masood; Ahmad, Latif; Gulzar, M. Mudassar

2018-03-01

The impact of temperature dependent thermal conductivity and convective surface conditions on unsteady 3D Sisko nanofluid flow over a stretching surface is studied in the presence of heat generation/absorption and magnetic field. The numerical solution of nonlinear coupled equations has been carried out to explore the properties of different physical profiles of the fluid flow with varying of parameters. Specifically, the application of generalized Biot numbers and heat generation/absorption parameter in the sketching of temperature and concentration profiles are explored. The effect of all three parameters is noticed in the increasing order for shear thinning (0 < n < 1) and for shear thickening (n > 1) fluids. Moreover, the influence of Biot number γ1 on heat and mass transfer rates, are found in the enhancement and diminishing conducts respectively, in both cases of shear thinning as well as shear thickening fluids and a reverse trend is observed with the variation of Biot number γ2 . Additionally, the present results are validated through skin friction, heat and mass transfer rate values with the comparable values in the existing previous values.

Status of the NASA-Lewis flat-plate collector tests with a solar simulator

NASA Technical Reports Server (NTRS)

Simon, F. F.

1974-01-01

Simulator test results of 15 collector types are presented. Collectors are given performance ratings according to their use for pool heating, hot water, absorption A/C or heating, and solar Rankine machines. Collectors found to be good performers in the above categories, except for pool heating, were a black nickel coated, 2 glass collector, and a black paint 2 glass collector containing a mylar honeycomb. For pool heating, a black paint, one glass collector was found to be the best performer. Collector performance parameters of 5 collector types were determined to aid in explaining the factors that govern performance. The two factors that had the greatest effect on collector performance were the collector heat loss and the coating absorptivity.

Comparison of the Radiative Two-Flux and Diffusion Approximations

NASA Technical Reports Server (NTRS)

Spuckler, Charles M.

2006-01-01

Approximate solutions are sometimes used to determine the heat transfer and temperatures in a semitransparent material in which conduction and thermal radiation are acting. A comparison of the Milne-Eddington two-flux approximation and the diffusion approximation for combined conduction and radiation heat transfer in a ceramic material was preformed to determine the accuracy of the diffusion solution. A plane gray semitransparent layer without a substrate and a non-gray semitransparent plane layer on an opaque substrate were considered. For the plane gray layer the material is semitransparent for all wavelengths and the scattering and absorption coefficients do not vary with wavelength. For the non-gray plane layer the material is semitransparent with constant absorption and scattering coefficients up to a specified wavelength. At higher wavelengths the non-gray plane layer is assumed to be opaque. The layers are heated on one side and cooled on the other by diffuse radiation and convection. The scattering and absorption coefficients were varied. The error in the diffusion approximation compared to the Milne-Eddington two flux approximation was obtained as a function of scattering coefficient and absorption coefficient. The percent difference in interface temperatures and heat flux through the layer obtained using the Milne-Eddington two-flux and diffusion approximations are presented as a function of scattering coefficient and absorption coefficient. The largest errors occur for high scattering and low absorption except for the back surface temperature of the plane gray layer where the error is also larger at low scattering and low absorption. It is shown that the accuracy of the diffusion approximation can be improved for some scattering and absorption conditions if a reflectance obtained from a Kubelka-Munk type two flux theory is used instead of a reflection obtained from the Fresnel equation. The Kubelka-Munk reflectance accounts for surface reflection and radiation scattered back by internal scattering sites while the Fresnel reflection only accounts for surface reflections.

Design considerations regarding an atomizer for multi-element electrothermal atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Katskov, Dmitri A.; Sadagov, Yuri M.

2011-06-01

The methodology of simultaneous multi-element electrothermal atomic absorption spectrometry (ETAAS-Electrothermal Atomic Absorption Spectrometry) stipulates rigid requirements to the design and operation of the atomizer. It must provide high degree of atomization for the group of analytes, invariant respective to the vaporization kinetics and heating ramp residence time of atoms in the absorption volume and absence of memory effects from major sample components. For the low resolution spectrometer with a continuum radiation source the reduced compared to traditional ETAAS (Electrothermal Atomic Absorption Spectrometry) sensitivity should be, at least partially, compensated by creating high density of atomic vapor in the absorption pulse. The sought-for characteristics were obtained for the 18 mm in length and 2.5 mm in internal diameter longitudinally heated graphite tube atomizer furnished with 2-4.5 mg of ring shaped carbon fiber yarn collector. The collector located next to the sampling port provides large substrate area that helps to keep the sample and its residue in the central part of the tube after drying. The collector also provides a "platform" effect that delays the vaporization and stipulates vapor release into absorption volume having already stabilized gas temperature. Due to the shape of external surface of the tube, presence of collector and rapid (about 10 °C/ms) heating, an inverse temperature distribution along the tube is attained at the beginnings of the atomization and cleaning steps. The effect is employed for cleaning of the atomizer using the set of short maximum power heating pulses. Preparation, optimal maintenance of the atomizer and its compliance to the multi-element determination requirements are evaluated and discussed. The experimental setup provides direct simultaneous determination of large group of element within 3-4 order concentration range. Limits of detection are close to those for sequential single element determination in Flame AAS with primary line source that is 50-1000 times higher than the limits obtainable with common ETAAS (Electrothermal Atomic Absorption Spectrometry) instrumentation.

Direct fired heat exchanger

DOEpatents

Reimann, Robert C.; Root, Richard A.

1986-01-01

A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

Passive thermo-optic feedback for robust athermal photonic systems

DOEpatents

Rakich, Peter T.; Watts, Michael R.; Nielson, Gregory N.

2015-06-23

Thermal control devices, photonic systems and methods of stabilizing a temperature of a photonic system are provided. A thermal control device thermally coupled to a substrate includes a waveguide for receiving light, an absorption element optically coupled to the waveguide for converting the received light to heat and an optical filter. The optical filter is optically coupled to the waveguide and thermally coupled to the absorption element. An operating point of the optical filter is tuned responsive to the heat from the absorption element. When the operating point is less than a predetermined temperature, the received light is passed to the absorption element via the optical filter. When the operating point is greater than or equal to the predetermined temperature, the received light is transmitted out of the thermal control device via the optical filter, without being passed to the absorption element.

High enthalpy arc-heated plasma flow diagnostics by tunable diode laser absorption spectroscopy

NASA Astrophysics Data System (ADS)

Lin, Xin; Chen, Lianzhong; Zeng, Hui; Ou, Dongbin; Dong, Yonghui

2017-05-01

This paper reports the laser absorption measurements of atomic oxygen in the FD04 arc-heater at China Academy of Aerospace Aerodynamics (CAAA). An atomic oxygen absorption line at 777.19 nm is utilizied for detecting the population of electronically excited oxygen atom in an air plasma flow. A scanned-wavelength direct absorption mode is used in this study. The laser is scanned in wavelength across the absorption feature at a rate of 200 Hz. Under the assumption of thermal equilibrium, time-resolved temperature measurements are obtained on one line-of-sight in the arc-heater. The good agreement of the temperature inferred from the sonic throat method suggests the equilibrium assumption is valid. These results illustrate the feasibility of the diode laser sensors for flow parameters in high enthalpy arc-heated facilities.

Cesium Absorption Spectrum Perturbed by Argon: Observation of Non-Lorentzian Wing Properties

DTIC Science & Technology

2012-03-01

vapor phase Cs contained in a heat pipe in order to observe the absorption lines. Two lenses were used to collimate the light through the heat pipe...After passing through the heat pipe, a mirror was used to direct light around a 90 degree turn and then through an f/# matched lens into a monochromator...pipe used here was built by Charles Fox as part of [19]. Brewster’s angle windows were attached to either end of a pipe approximately 1 inch in diameter

Integration of a molten carbonate fuel cell with a direct exhaust absorption chiller

NASA Astrophysics Data System (ADS)

Margalef, Pere; Samuelsen, Scott

A high market value exists for an integrated high-temperature fuel cell-absorption chiller product throughout the world. While high-temperature, molten carbonate fuel cells are being commercially deployed with combined heat and power (CHP) and absorption chillers are being commercially deployed with heat engines, the energy efficiency and environmental attributes of an integrated high-temperature fuel cell-absorption chiller product are singularly attractive for the emerging distributed generation (DG) combined cooling, heating, and power (CCHP) market. This study addresses the potential of cooling production by recovering and porting the thermal energy from the exhaust gas of a high-temperature fuel cell (HTFC) to a thermally activated absorption chiller. To assess the practical opportunity of serving an early DG-CCHP market, a commercially available direct fired double-effect absorption chiller is selected that closely matches the exhaust flow and temperature of a commercially available HTFC. Both components are individually modeled, and the models are then coupled to evaluate the potential of a DG-CCHP system. Simulation results show that a commercial molten carbonate fuel cell generating 300 kW of electricity can be effectively coupled with a commercial 40 refrigeration ton (RT) absorption chiller. While the match between the two "off the shelf" units is close and the simulation results are encouraging, the match is not ideal. In particular, the fuel cell exhaust gas temperature is higher than the inlet temperature specified for the chiller and the exhaust flow rate is not sufficient to achieve the potential heat recovery within the chiller heat exchanger. To address these challenges, the study evaluates two strategies: (1) blending the fuel cell exhaust gas with ambient air, and (2) mixing the fuel cell exhaust gases with a fraction of the chiller exhaust gas. Both cases are shown to be viable and result in a temperature drop and flow rate increase of the gases before the chiller inlet. The results show that no risk of cold end corrosion within the chiller heat exchanger exists. In addition, crystallization is not an issue during system operation. Accounting for the electricity and the cooling produced and disregarding the remaining thermal energy, the second strategy is preferred and yields an overall estimated efficiency of 71.7%.

Comparative performance of twenty-three types of flat plate solar energy collectors

NASA Technical Reports Server (NTRS)

Simon, F. F.

1975-01-01

Report compares efficiencies of 23 solar collectors for four different purposes: operating a Rankine-cycle engine, heating or absorption air conditioning, heating hot water, and heating a swimming pool.

Differential-optoacoustic absorption detector

NASA Technical Reports Server (NTRS)

Shumate, M. S.

1977-01-01

Two-cell spectrophone detects trace amounts of atmospheric pollutants by measuring absorption coefficients of gases with various laser sources. Device measures pressure difference between two tapered cells with differential manometer. Background signal is reduced by balanced window heating and balanced carrier gas absorption in two cells.

A simple heat-pipe cell for X-ray absorption spectrometry of potassium vapor

NASA Astrophysics Data System (ADS)

Pres̆eren, R.; Kodre, A.; Arc̆on, I.; Padez̆nik Gomils̆ek, J.; Hribar, M.

1999-01-01

The construction and operation of a simple high-temperature X-ray absorption cell for potassium vapor is described. The principle of "spectroscopic heat pipe" is exploited to separate kapton windows, indispensable for good transmission in the low-energy region, from the hot and aggressive vapor. High-resolution spectrum of the K-edge region of atomic potassium reveals fingerprints of multielectron photoexcitations.

ICRF heating in a straight, helically symmetric stellarator

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

Jaeger, E.F.; Weitzner, H.; Batchelor, D.B.

1987-07-01

Experimental observations of direct ion cyclotron resonant frequency (ICRF) heating at fundamental ion cyclotron resonance on the L-2 stellarator have stimulated interest in the theoretical basis for such heating. In this paper, global solutions for the ICRF wave fields in a helically symmetric, straight stellarator are calculated in the cold plasma limit. The component of the wave electric field parallel to B-vector is assumed zero. Helical symmetry allows Fourier decomposition in the longitudinal (z) direction. The two remaining partial differential equations in tau and phi identical to THETA - hz (h is the helical pitch) are solved by finite differencing.more » Energy absorption and antenna impedance are calculated from an ad hoc collision model. Results for parameters typical of the L-2 and Advanced Toroidal Facility (ATF) stellarators show that direct resonant absorption of the fundamental ion cyclotron resonance occurs mainly near the plasma edge. The magnitude of the absorption is about half that for minority heating at the two-ion hybrid resonance.« less

Triple-effect absorption chiller cycle: A step beyond double-effect cycles

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

DeVault, R.C.

1990-01-01

Many advanced'' absorption cycles have been proposed during the current century. Of the hundreds of absorption cycles which have been patented throughout the world, all commercially manufactured products for air conditioning buildings have been variations of just two basic absorption cycles: single-effect and condenser-coupled double-effect cycles. The relatively low cooling coefficients of performance (COPs) inherent in single-effect and double-effect cycles limits the economic applicability of absorption air conditioners (chillers) in the United States. A triple-effect absorption chiller cycle is discussed. This cycle uses two condensers and two absorbers to achieve the triple effect.'' Depending on the absorption fluids selected, thismore » triple-effect cycle is predicted to improve cooling COPs by 18% to 60% compared with the equivalent double-effect cycle. This performance improvement is obtained without increasing the total amount of heat-transfer surface area needed for the heat exchangers. A comparison between the calculated performances of a double-effect cycle and a triple-effect cycle (both using ammonia-water (NH{sub 3}/H{sub 2}O) as the absorption fluid pair) is presented. The triple-effect cycle is predicted to have an 18% higher cooling COP (1.41 compared with 1.2 for a double-effect), lower pressure (47.70 atm (701 psi) instead of 68.05 atm (1000 psi)), significantly reduced pumping power (less than one-half that of the double-effect cycle), and potentially lower construction cost (33% less total heat exchange needed). Practical implications for this triple-effect cycle are discussed. 16 refs., 5 figs., 1 tab.« less

Nonlinear Absorption and Heating of Dense Plasmas.

DTIC Science & Technology

plasma focus both illuminated by a high intensity CO2 laser. Results indicate the previously noted increases in absorption due to the inclusion of the nonlinear saturation mechanism. The previously obtained increases in absorption with increasing density scale height and decreasing temperatures are also recovered. The

High-Absorptance Radiative Heat Sink

NASA Technical Reports Server (NTRS)

Cafferty, T.

1983-01-01

Absorptance of black-painted open-cell aluminum honeycomb improved by cutting honeycomb at angle or bias rather than straight across. This ensures honeycomb cavities escapes. At each reflection radiation attenuated by absorption. Applications include space-background simulators, space radiators, solar absorbers, and passive coolers for terrestrial use.

Lack of evidence in vivo for a remote effect of Escherichia coli heat stable enterotoxin on jejunal fluid absorption.

PubMed

Lucas, M L; Duncan, N W; o'reilly, N F; McIlvenny, T J; Nelson, Y B

2008-05-01

On contact with the mucosa, heat stable (STa) enterotoxin from Escherichia coli reduces fluid absorption in vivo in the perfused jejunum of the anaesthetized rat. The question of whether it also has a vagally mediated remote action on jejunal absorption, when instilled into the ileum, was re-examined, given contradictory findings in the literature. A standard perfused loop preparation was used to measure luminal uptake of fluid in vivo by means of volume recovery. STa in the ileum was found to have no effect on jejunal absorption, regardless of cervical or sub-diaphragmatic vagotomy and also regardless of the nature of the perfusate anion. The batches of toxin were shown in parallel experiments to reduce fluid absorption directly in the jejunum and also in the ileum. Similarly, vagal nerves prior to section had demonstrable in vivo physiological function. There was therefore no evidence for an indirect, vagally mediated ileal effect of STa on proximal fluid absorption.

Heat exchange studies on coconut oil cells as thermal energy storage for room thermal conditioning

NASA Astrophysics Data System (ADS)

Sutjahja, I. M.; Putri, Widya A.; Fahmi, Z.; Wonorahardjo, S.; Kurnia, D.

2017-07-01

As reported by many thermal environment experts, room air conditioning might be controlled by thermal mass system. In this paper we discuss the performance of coconut oil cells as room thermal energy storage. The heat exchange mechanism of coconut oil (CO) which is one of potential organic Phase Change Material (PCM) is studied based on the results of temperature measurements in the perimeter and core parts of cells. We found that the heat exchange performance, i.e. heat absorption and heat release processes of CO cells are dominated by heat conduction in the sensible solid from the higher temperature perimeter part to the lower temperature core part and heat convection during the solid-liquid phase transition and sensible liquid phase. The capability of heat absorption as measured by the reduction of air temperature is not influenced by CO cell size. Besides that, the application of CO as the thermal mass has to be accompanied by air circulation to get the cool sensation of the room’s occupants.

Indirect-fired gas turbine bottomed with fuel cell

DOEpatents

Micheli, P.L.; Williams, M.C.; Parsons, E.L.

1995-09-12

An indirect-heated gas turbine cycle is bottomed with a fuel cell cycle with the heated air discharged from the gas turbine being directly utilized at the cathode of the fuel cell for the electricity-producing electrochemical reaction occurring within the fuel cell. The hot cathode recycle gases provide a substantial portion of the heat required for the indirect heating of the compressed air used in the gas turbine cycle. A separate combustor provides the balance of the heat needed for the indirect heating of the compressed air used in the gas turbine cycle. Hot gases from the fuel cell are used in the combustor to reduce both the fuel requirements of the combustor and the NOx emissions therefrom. Residual heat remaining in the air-heating gases after completing the heating thereof is used in a steam turbine cycle or in an absorption refrigeration cycle. Some of the hot gases from the cathode can be diverted from the air-heating function and used in the absorption refrigeration cycle or in the steam cycle for steam generating purposes. 1 fig.

Indirect-fired gas turbine bottomed with fuel cell

DOEpatents

Micheli, Paul L.; Williams, Mark C.; Parsons, Edward L.

1995-01-01

An indirect-heated gas turbine cycle is bottomed with a fuel cell cycle with the heated air discharged from the gas turbine being directly utilized at the cathode of the fuel cell for the electricity-producing electrochemical reaction occurring within the fuel cell. The hot cathode recycle gases provide a substantial portion of the heat required for the indirect heating of the compressed air used in the gas turbine cycle. A separate combustor provides the balance of the heat needed for the indirect heating of the compressed air used in the gas turbine cycle. Hot gases from the fuel cell are used in the combustor to reduce both the fuel requirements of the combustor and the NOx emissions therefrom. Residual heat remaining in the air-heating gases after completing the heating thereof is used in a steam turbine cycle or in an absorption refrigeration cycle. Some of the hot gases from the cathode can be diverted from the air-heating function and used in the absorption refrigeration cycle or in the steam cycle for steam generating purposes.

The Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes

NASA Astrophysics Data System (ADS)

Wong, Elizabeth Wing-See

There is much evidence that the ocean is heating as a result of an increase in concentrations of greenhouse gases (GHGs) in the atmosphere from human activities. GHGs absorb infrared radiation and re-emit infrared radiation back to the ocean's surface which is subsequently absorbed. However, the incoming infrared radiation is absorbed within the top micrometers of the ocean's surface which is where the thermal skin layer exists. Thus the incident infrared radiation does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of infrared radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that since heat lost through the air-sea interface is controlled by the thermal skin layer, which is directly influenced by the absorption and emission of infrared radiation, the heat flow through the thermal skin layer adjusts to maintain the surface heat loss, assuming the surface heat loss does not vary, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in incoming longwave radiation and analyzing retrieved thermal skin layer vertical temperature profiles from a shipboard infrared spectrometer from two research cruises. The data are limited to night-time, no precipitation and low winds of less than 2 m/s to remove effects of solar radiation, wind-driven shear and possibilities of thermal skin layer disruption. The results show independence of the turbulent fluxes and emitted radiation on the incident radiative fluxes which rules out the immediate release of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation and increase infrared emission. Furthermore, independence was confirmed between the incoming and outgoing radiative flux which implies the heat sink for upward flowing heat at the air-sea interface is more-or-less fixed. The surplus energy, from absorbing increasing levels of infrared radiation, is found to adjust the curvature of the thermal skin layer such that there is a smaller gradient at the interface between the thermal skin layer and the mixed layer beneath. The vertical conduction of heat from the mixed layer to the surface is therefore hindered while the additional energy within the thermal skin layer is supporting the gradient changes of the skin layer's temperature profile. This results in heat beneath the thermal skin layer, which is a product of the absorption of solar radiation during the day, to be retained and cause an increase in upper ocean heat content. The accuracy of four published skin layer models were evaluated by comparison with the field results. The results show a need to include radiative effects, which are currently absent, in such models as they do not replicate the findings from the field data and do not elucidate the effects of the absorption of infrared radiation.

Measurement and analysis of x-ray absorption in Al and MgF2 plasmas heated by Z-pinch radiation.

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

MacFarlane, Joseph John; Rochau, Gregory Alan; Bailey, James E.

2005-06-01

High-power Z pinches on Sandia National Laboratories Z facility can be used in a variety of experiments to radiatively heat samples placed some distance away from the Z-pinch plasma. In such experiments, the heating radiation spectrum is influenced by both the Z-pinch emission and the re-emission of radiation from the high-Z surfaces that make up the Z-pinch diode. To test the understanding of the amplitude and spectral distribution of the heating radiation, thin foils containing both Al and MgF{sub 2} were heated by a 100-130 TW Z pinch. The heating of these samples was studied through the ionization distribution inmore » each material as measured by x-ray absorption spectra. The resulting plasma conditions are inferred from a least-squares comparison between the measured spectra and calculations of the Al and Mg 1s {yields} 2p absorption over a large range of temperatures and densities. These plasma conditions are then compared to radiation-hydrodynamics simulations of the sample dynamics and are found to agree within 1{sigma} to the best-fit conditions. This agreement indicates that both the driving radiation spectrum and the heating of the Al and MgF{sub 2} samples is understood within the accuracy of the spectroscopic method.« less

RF absorption and ion heating in helicon sources.

PubMed

Kline, J L; Scime, E E; Boivin, R F; Keesee, A M; Sun, X; Mikhailenko, V S

2002-05-13

Experimental data are presented that are consistent with the hypothesis that anomalous rf absorption in helicon sources is due to electron scattering arising from parametrically driven ion-acoustic waves downstream from the antenna. Also presented are ion temperature measurements demonstrating anisotropic heating (T( perpendicular)>T(parallel)) at the edge of the discharge. The most likely explanation is ion-Landau damping of electrostatic slow waves at a local lower-hybrid-frequency resonance.

Optical absorption and TEM studies of silver nanoparticle embedded BaO-CaF{sub 2}-P{sub 2}O{sub 5} glasses

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

Narayanan, Manoj Kumar, E-mail: manukokkal01@gmail.com; Shashikala, H. D.

Silver nanoparticle embedded 30BaO-20CaF{sub 2}-50P{sub 2}O{sub 5}-4Ag{sub 2}O-4SnO glasses were prepared by melt-quenching and subsequent heat treatment process. Silver-doped glasses were heat treated at temperatures 500 °C, 525°C and 550 °C for a fixed duration of 10 hours to incorporate metal nanoparticles into the glass matrix. Appearance and shift in peak positions of the surface plasmon resonance (SPR) bands in the optical absorption spectra of heat treated glass samples indicated that both formation and growth of nanoparticle depended on heat treatment temperature. Glass sample heat treated at 525 °C showed a SPR peak around 3 eV, which indicated that sphericalmore » nanoparticles smaller than 20 nm were formed inside the glass matrix. Whereas sample heat treated at 550 °C showed a size dependent red shift in SPR peak due to the presence of silver nanoparticles of size larger than 20 nm. Size of the nanoparticles calculated using full-width at half-maximum (FWHM) of absorption band showed a good agreement with the particle size obtained from transmission electron microscopy (TEM) analysis.« less

Effects of heat transfer and energy absorption in the ablation of biological tissues by pulsetrain-burst (>100 MHz) ultrafast laser processing

NASA Astrophysics Data System (ADS)

Forrester, Paul; Bol, Kieran; Lilge, Lothar; Marjoribanks, Robin

2006-09-01

Energy absorption and heat transfer are important factors for regulating the effects of ablation of biological tissues. Heat transfer to surrounding material may be desirable when ablating hard tissue, such as teeth or bone, since melting can produce helpful material modifications. However, when ablating soft tissue it is important to minimize heat transfer to avoid damage to healthy tissue - for example, in eye refractive surgery (e.g., Lasik), nanosecond pulses produce gross absorption and heating in tissue, leading to shockwaves, which kill and thin the non-replicating epithelial cells on the inside of the cornea; ultrafast pulses are recognized to reduce this effect. Using a laser system that delivers 1ps pulses in 10μs pulsetrains at 133MHz we have studied a range of heat- and energy-transfer effects on hard and soft tissue. We describe the ablation of tooth dentin and enamel under various conditions to determine the ablation rate and chemical changes that occur. Furthermore, we characterize the impact of pulsetrain-burst treatment of collagen-based tissue to determine more efficient methods of energy transfer to soft tissues. By studying the optical science of laser tissue interaction we hope to be able to make qualitative improvements to medical treatments using lasers.

Near-field three-terminal thermoelectric heat engine

NASA Astrophysics Data System (ADS)

Jiang, Jian-Hua; Imry, Yoseph

2018-03-01

We propose a near-field inelastic thermoelectric heat engine where quantum dots are used to effectively rectify the charge flow of photocarriers. The device converts near-field heat radiation into useful electrical power. Heat absorption and inelastic transport can be enhanced by introducing two continuous spectra separated by an energy gap. The thermoelectric transport properties of the heat engine are studied in the linear-response regime. Using a small band-gap semiconductor as the absorption material, we show that the device achieves very large thermopower and thermoelectric figure of merit, as well as considerable power factor. By analyzing thermal-photocarrier generation and conduction, we reveal that the Seebeck coefficient and the figure of merit have oscillatory dependence on the thickness of the vacuum gap. Meanwhile, the power factor, the charge, and thermal conductivity are significantly improved by near-field radiation. Conditions and guiding principles for powerful and efficient thermoelectric heat engines are discussed in details.

Laser engines operating by resonance absorption. [thermodynamic feasibility study

NASA Technical Reports Server (NTRS)

Garbuny, M.; Pechersky, M. J.

1976-01-01

Basic tutorial article on the thermodynamic feasibility of laser engines at the present state of the art. Three main options are considered: (1) laser power applied externally to a heat reservoir (boiler approach); (2) internal heating of working fluid by resonance absorption; and (3) direct conversion of selective excitation into work. Only (2) is considered practically feasible at present. Basic concepts and variants, efficiency relations, upper temperature limits of laser engines, selection of absorbing gases, engine walls, bleaching, thermodynamic cycles of optimized laser engines, laser-powered turbines, laser heat pumps are discussed. Photon engines and laser dissociation engines are also considered.

Performance analysis of single stage libr-water absorption machine operated by waste thermal energy of internal combustion engine: Case study

NASA Astrophysics Data System (ADS)

Sharif, Hafiz Zafar; Leman, A. M.; Muthuraman, S.; Salleh, Mohd Najib Mohd; Zakaria, Supaat

2017-09-01

Combined heating, cooling, and power is also known as Tri-generation. Tri-generation system can provide power, hot water, space heating and air -conditioning from single source of energy. The objective of this study is to propose a method to evaluate the characteristic and performance of a single stage lithium bromide-water (LiBr-H2O) absorption machine operated with waste thermal energy of internal combustion engine which is integral part of trigeneration system. Correlations for computer sensitivity analysis are developed in data fit software for (P-T-X), (H-T-X), saturated liquid (water), saturated vapor, saturation pressure and crystallization temperature curve of LiBr-H2O Solution. Number of equations were developed with data fit software and exported into excel work sheet for the evaluation of number of parameter concerned with the performance of vapor absorption machine such as co-efficient of performance, concentration of solution, mass flow rate, size of heat exchangers of the unit in relation to the generator, condenser, absorber and evaporator temperatures. Size of vapor absorption machine within its crystallization limits for cooling and heating by waste energy recovered from exhaust gas, and jacket water of internal combustion engine also presented in this study to save the time and cost for the facilities managers who are interested to utilize the waste thermal energy of their buildings or premises for heating and air conditioning applications.

The impact of short-term heat storage on the ice-albedo feedback loop

NASA Astrophysics Data System (ADS)

Polashenski, C.; Wright, N.; Perovich, D. K.; Song, A.; Deeb, E. J.

2016-12-01

The partitioning of solar energy in the ice-ocean-atmosphere environment is a powerful control over Arctic sea ice mass balance. Ongoing transitions of the sea ice toward a younger, thinner state are enhancing absorption of solar energy and contributing to further declines in sea ice in a classic ice-albedo feedback. Here we investigate the solar energy balance over shorter timescales. In particular, we are concerned with short term delays in the transfer of absorbed solar energy to the ice caused by heat storage in the upper ocean. By delaying the realization of ice melt, and hence albedo decline, heat storage processes effectively retard the intra-season ice-albedo feedback. We seek to quantify the impact and variability of such intra-season storage delays on full season energy absorption. We use in-situ data collected from Arctic Observing Network (AON) sea ice sites, synthesized with the results of imagery processed from high resolution optical satellites, and basin-scale remote sensing products to approach the topic. AON buoys are used to monitor the storage and flux of heat, while satellite imagery allows us to quantify the evolution of surrounding ice conditions and predict the aggregate scale solar absorption. We use several test sites as illustrative cases and demonstrate that temporary heat storage can have substantial impacts on seasonal energy absorption and ice loss. A companion to this work is presented by N. Wright at this meeting.

The Influence of Wavelength-Dependent Absorption and Temperature Gradients on Temperature Determination in Laser-Heated Diamond-Anvil Cells

NASA Astrophysics Data System (ADS)

Deng, J.; Lee, K. K. M.; Du, Z.; Benedetti, L. R.

2016-12-01

In situ temperature measurements in the laser-heated diamond-anvil cell (LHDAC) are among the most fundamental experiments undertaken in high-pressure science. Despite its importance, few efforts have been made to examine the alteration of thermal radiation spectra of hot samples by wavelength-dependent absorption of the sample itself together with temperature gradients within samples while laser heating and their influence on temperature measurement. For example, iron-bearing minerals show strong wavelength dependent absorption in the wavelength range used to determine temperature, which, together with temperature gradients can account for largely aliased apparent temperatures (e.g., 1200 K deviation for a 4000 K melting temperature) in some experiments obtained by fitting of detected thermal radiation intensities. As such, conclusions of melting temperatures, phase diagrams and partitioning behavior, may be grossly incorrect for these materials. In general, wavelength-dependent absorption and temperature gradients of samples are two key factors to consider in order to rigorously constrain temperatures, which have been largely ignored in previous LHDAC studies. A reevaluation of temperatures measured in recent high-profile papers will be reviewed.

Sorption Isotherm Modelling Of Fermented Cassava Flour by Red Yeast Rice

NASA Astrophysics Data System (ADS)

Cahyanti, M. N.; Alfiah, M. N.; Hartini, S.

2018-04-01

The objective of the study is to determine the characteristic of moisture sorption isotherm from fermented cassava flour by red yeast rice using various modeling. This research used seven salt solutions and storage temperature of 298K, 303K, and 308K. The models used were Brunauer-Emmet-Teller (BET), Guggenheim-Anderson-de Boer (GAB) and Caurie model. The monolayer moisture content was around 4.51 – 5.99% db. Constant related to absorption heat in the multilayer area of [GAB model was around 0.86-0,91. Constant related to absorption heat in the monolayer area of GAB model was around 4.67-5.97. Constant related to absorption heat in the monolayer area of BET model was around 4.83-7.04. Caurie constant was around 1.25-1.59. The equilibrium and monolayer moisture content on fermented cassava flour by red yeast rice was decreasing as increasing temperature. GAB constant value indicated that the process of moisture absorption on the fermented cassava flour by red yeast rice categorized in type II.

Unraveling Main Limiting Sites of Photosynthesis under Below- and Above-Ground Heat Stress in Cucumber and the Alleviatory Role of Luffa Rootstock.

PubMed

Li, Hao; Ahammed, Golam J; Zhou, Guona; Xia, Xiaojian; Zhou, Jie; Shi, Kai; Yu, Jingquan; Zhou, Yanhong

2016-01-01

Photosynthesis is one of the most thermo-sensitive processes in plants. Although the severity of heat stress could be attenuated by grafting approach, the primary damaged site of photosynthesis system under heat stress and the regulatory mechanism of rootstock-mediated heat tolerance are poorly understood. In the current study, cucumber plants grafted onto their own roots and heat-tolerant luffa roots were exposed to root-zone heat (25/40°C) and aerial heat (40/25°C) individually and in combination (40/40°C) to understand the response of photosynthetic process by investigating energy absorption and distribution, electron transport in photosystem (PS) II and I, and CO2 assimilation. According to the results, root-zone heat stress inhibited photosynthesis mainly through decreasing Rubisco activity, while aerial heat stress mainly through inhibiting PSII acceptor side. The imbalance in light absorption and utilization resulted in accumulation of reactive oxygen species that caused damage to photosynthetic apparatus, forming a vicious cycle. On the contrary, grafting cucumber onto heat-tolerant luffa rootstock alleviated heat-induced photosynthetic inhibition and oxidative stress by maintaining higher root vitality, HSP70 accumulation, and antioxidant potential.

Improve the material absorption of light and enhance the laser tube bending process utilizing laser softening heat treatment

NASA Astrophysics Data System (ADS)

Imhan, Khalil Ibraheem; Baharudin, B. T. H. T.; Zakaria, Azmi; Ismail, Mohd Idris Shah B.; Alsabti, Naseer Mahdi Hadi; Ahmad, Ahmad Kamal

2018-02-01

Laser forming is a flexible control process that has a wide spectrum of applications; particularly, laser tube bending. It offers the perfect solution for many industrial fields, such as aerospace, engines, heat exchangers, and air conditioners. A high power pulsed Nd-YAG laser with a maximum average power of 300 W emitting at 1064 nm and fiber-coupled is used to irradiate stainless steel 304 (SS304) tubes of 12.7 mm diameter, 0.6 mm thickness and 70 mm length. Moreover, a motorized rotation stage with a computer controller is employed to hold and rotate the tube. In this paper, an experimental investigation is carried out to improve the laser tube bending process by enhancing the absorption coefficient of the material and the mechanical formability using laser softening heat treatment. The material surface is coated with an oxidization layer; hence, the material absorption of laser light is increased and the temperature rapidly rises. The processing speed is enhanced and the output bending angle is increased to 1.9° with an increment of 70% after the laser softening heat treatment.

Nonlinear absorption in biological tissue for high intensity focused ultrasound.

PubMed

Liu, Xiaozhou; Li, Junlun; Gong, Xiufen; Zhang, Dong

2006-12-22

In recent years the propagation of the high intensity focused ultrasound (HIFU) in biological tissue is an interesting area due to its potential applications in non-invasive treatment of disease. The base principle of these applications is the heat effect generated by ultrasound absorption. In order to control therapeutic efficiency, it is important to evaluate the heat generation in biological tissue irradiated by ultrasound. In his paper, based on the Khokhlov-Zabolotkaya-Kuznetsov (KZK) equation in frequency-domain, the numerical simulations of nonlinear absorption in biological tissues for high intensity focused ultrasound are performed. We find that ultrasound thermal transfer effect will be enhanced with the increasing of initial acoustic intensity due to the high harmonic generation. The concept of extra absorption factor is introduced to describe nonlinear absorption in biological tissue for HIFU. The theoretical results show that the heat deposition induced by the nonlinear theory can be nearly two times as large as that predicated by linear theory. Then, the influence of the diffraction effect on the position of the focus in HIFU is investigated. It is shown that the sound focus moves toward the transducer compared with the geometry focus because of the diffraction of the sound wave. The position of the maximum heat deposition is shifted to the geometry focus with the increase of initial acoustic intensity because the high harmonics are less diffraction. Finally, the temperature in the porcine fat tissue changing with the time is predicated by Pennes' equation and the experimental results verify the nonlinear theoretical prediction.

Cloud Cover Increase with Increasing Aerosol Absorptivity: A Counterexample to the Conventional Semidirect Aerosol Effect

NASA Technical Reports Server (NTRS)

Perlwitz, Jan; Miller, Ron L.

2010-01-01

We reexamine the aerosol semidirect effect using a general circulation model and four cases of the single-scattering albedo of dust aerosols. Contrary to the expected decrease in low cloud cover due to heating by tropospheric aerosols, we find a significant increase with increasing absorptivity of soil dust particles in regions with high dust load, except during Northern Hemisphere winter. The strongest sensitivity of cloud cover to dust absorption is found over land during Northern Hemisphere summer. Here even medium and high cloud cover increase where the dust load is highest. The cloud cover change is directly linked to the change in relative humidity in the troposphere as a result of contrasting changes in specific humidity and temperature. More absorption by aerosols leads to larger diabatic heating and increased warming of the column, decreasing relative humidity. However, a corresponding increase in the specific humidity exceeds the temperature effect on relative humidity. The net effect is more low cloud cover with increasing aerosol absorption. The higher specific humidity where cloud cover strongly increases is attributed to an enhanced convergence of moisture driven by dust radiative heating. Although in some areas our model exhibits a reduction of low cloud cover due to aerosol heating consistent with the conventional description of the semidirect effect, we conclude that the link between aerosols and clouds is more varied, depending also on changes in the atmospheric circulation and the specific humidity induced by the aerosols. Other absorbing aerosols such as black carbon are expected to have a similar effect.

Estimating nanoparticle optical absorption with magnetic resonance temperature imaging and bioheat transfer simulation.

PubMed

MacLellan, Christopher J; Fuentes, David; Elliott, Andrew M; Schwartz, Jon; Hazle, John D; Stafford, R Jason

2014-02-01

Optically activated nanoparticle-mediated heating for thermal therapy applications is an area of intense research. The ability to characterise the spatio-temporal heating potential of these particles for use in modelling under various exposure conditions can aid in the exploration of new approaches for therapy as well as more quantitative prospective approaches to treatment planning. The purpose of this research was to investigate an inverse solution to the heat equation using magnetic resonance temperature imaging (MRTI) feedback, for providing optical characterisation of two types of nanoparticles (gold-silica nanoshells and gold nanorods). The optical absorption of homogeneous nanoparticle-agar mixtures was measured during exposure to an 808 nm laser using real-time MRTI. A coupled finite element solution of heat transfer was registered with the data and used to solve the inverse problem. The L2 norm of the difference between the temperature increase in the model and MRTI was minimised using a pattern search algorithm by varying the absorption coefficient of the mixture. Absorption fractions were within 10% of literature values for similar nanoparticles. Comparison of temporal and spatial profiles demonstrated good qualitative agreement between the model and the MRTI. The weighted root mean square error was <1.5 σMRTI and the average Dice similarity coefficient for ΔT = 5 °C isotherms was >0.9 over the measured time interval. This research demonstrates the feasibility of using an indirect method for making minimally invasive estimates of nanoparticle absorption that might be expanded to analyse a variety of geometries and particles of interest.

Miniaturized King furnace permits absorption spectroscopy of small samples

NASA Technical Reports Server (NTRS)

Ercoli, B.; Tompkins, F. S.

1968-01-01

Miniature King-type furnace, consisting of an inductively heated, small diameter tantalum tube supported in a radiation shield eliminates the disadvantages of the conventional furnace in obtaining absorption spectra of metal vapors.

Optical absorption and radiative heat transport in olivine at high temperature

NASA Technical Reports Server (NTRS)

Shankland, T. J.; Nitsan, U.; Duba, A. G.

1979-01-01

Results are presented of measurements of the optical absorption spectra (300-8000 nm) of olivine as a function of temperature (300-1700 K) under conditions of controlled and known oxygen fugacity within the stability field of the samples. The absorption spectra are used to calculate the temperature-dependent radiative transfer coefficient of olivine and to numerically study the accuracy of the method. The present absorption measurements in olivine under oxidizing conditions known to be within the olivine stability field indicate that the effective radiative conductivity K(R) is lower than that obtained in previous studies under different experimental conditions. The lower value of K(R) makes it more likely that some of the earth's internal heat is removed by convection and less likely that thermal models involving conduction and radiation alone will satisfactorily explain thermal conditions in the earth's mantle.

Optimization of absorption air-conditioning for solar energy applications

NASA Technical Reports Server (NTRS)

Perry, E. H.

1976-01-01

Improved performance of solar cooling systems using the lithium bromide water absorption cycle is investigated. Included are computer simulations of a solar-cooled house, analyses and measurements of heat transfer rates in absorption system components, and design and fabrication of various system components. A survey of solar collector convection suppression methods is presented.

Moderate temperature control technology for a lunar base

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.; Sridhar, K. R.; Gottmann, Matthias

1993-01-01

A parametric analysis is performed to compare different heat pump based thermal control systems for a Lunar Base. Rankine cycle and absorption cycle heat pumps are compared and optimized for a 100 kW cooling load. Variables include the use or lack of an interface heat exchanger, and different operating fluids. Optimization of system mass to radiator rejection temperature is performed. The results indicate a relatively small sensitivity of Rankine cycle system mass to these variables, with optimized system masses of about 6000 kg for the 100 kW thermal load. It is quantitaively demonstrated that absorption based systems are not mass competitive with Rankine systems.

Generalizing the flash technique in the front-face configuration to measure the thermal diffusivity of semitransparent solids

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

Pech-May, Nelson Wilbur; Department of Applied Physics, CINVESTAV Unidad Mérida, carretera Antigua a Progreso km6, A.P. 73 Cordemex, Mérida Yucatán 97310, México; Mendioroz, Arantza

2014-10-15

In this work, we have extended the front-face flash method to retrieve simultaneously the thermal diffusivity and the optical absorption coefficient of semitransparent plates. A complete theoretical model that allows calculating the front surface temperature rise of the sample has been developed. It takes into consideration additional effects, such as multiple reflections of the heating light beam inside the sample, heat losses by convection and radiation, transparency of the sample to infrared wavelengths, and heating pulse duration. Measurements performed on calibrated solids, covering a wide range of absorption coefficients (from transparent to opaque) and thermal diffusivities, validate the proposed method.

Costs and description of a solar-energy system--Austin, Texas

NASA Technical Reports Server (NTRS)

1981-01-01

Heating and cooling system uses Fresnel lens concentrating collectors. Major system components are 36 collectors, 1,500 gallon thermal storage tank, absorption cooler, cooling tower, heating coil, pumps, heat exchanger, and backup heating and air conditioning. Final report includes detailed breakdown of component and installation costs for seven project subsystems.

Non-Venting Thermal and Humidity Control for EVA Suits

NASA Technical Reports Server (NTRS)

Izenson, Mike; Chen, Weibo; Bue, Grant

2011-01-01

Future EVA suits need processes and systems to control internal temperature and humidity without venting water to the environment. This paper describes an absorption-based cooling and dehumidification system as well as laboratory demonstrations of the key processes. There are two main components in the system: an evaporation cooling and dehumidification garment (ECDG) that removes both sensible heat and latent heat from the pressure garment, and an absorber radiator that absorbs moisture and rejects heat to space by thermal radiation. This paper discusses the overall design of both components, and presents recent data demonstrating their operation. We developed a design and fabrication approach to produce prototypical heat/water absorbing elements for the ECDG, and demonstrated by test that these elements could absorb heat and moisture at a high flux. Proof-of-concept tests showed that an ECDG prototype absorbs heat and moisture at a rate of 85 W/ft under conditions that simulate operation in an EVA suit. The heat absorption was primarily due to direct absorption of water vapor. It is possible to construct large, flexible, durable cooling patches that can be incorporated into a cooling garment with this system. The proof-of-concept test data was scaled to calculate area needed for full metabolic loads, thus showing that it is feasible to use this technology in an EVA suit. Full-scale, lightweight absorber/radiator modules have also been built and tested. They can reject heat at a flux of 33 W/ft while maintaining ECDG operation at conditions that will provide a cool and dry environment inside the EVA suit.

Method and apparatus for selectively annealing heterostructures using microwave

NASA Technical Reports Server (NTRS)

Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

1998-01-01

The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

Method and apparatus for selectively annealing heterostructures using microwaves

NASA Technical Reports Server (NTRS)

Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

1998-01-01

The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

Color change of tourmaline by heat treatment and electron beam irradiation: UV-Visible, EPR, and Mid-IR spectroscopic analyses

NASA Astrophysics Data System (ADS)

Maneewong, Apichate; Seong, Baek Seok; Shin, Eun Joo; Kim, Jeong Seog; Kajornrith, Varavuth

2016-01-01

The color of pink tourmaline gemstone changed to colorless when heating at temperature of 600 °C in air. This colorless tourmaline recovered its pink color when irradiated with an electron beam (e-beam) of 800 kGy. The origin of the color change was investigated in three types of tourmaline gemstones, two pink are from Afghanistan and one green are from Nigeria, by using Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), Electron paramagnetic resonance (EPR), and Energy Dispersive X-ray Fluorescence (EDXRF). The UV-Vis absorption spectrum of the pink tourmaline with higher Mn concentration (T2, 0.24 wt%) showed characteristic absorption peaks originating from the Mn3+ color center: two absorption bands centered at wavelength of 396 and 520 nm, respectively. Both absorption bands disappeared when heated in air at 600 °C and then reappeared when irradiated with an e-beam at 800 kGy. EPR T2 spectra showed that the color change was related to the valence change of Mn3+ to Mn2+ and vice versa. The pink tourmaline of lower MnO content (T1, 0.08 wt%) also became colorless when heated, but the color was not recovered when the gemstone underwent e-beam irradiation. Instead, a yellow color was obtained. UV-Vis and FTIR spectra indicated that this yellow color originated from a decomposition of the hydroxyl group (-OH) into O- and Ho by the e-beam irradiation. Green tourmaline did not show any color change with either heat treatment or e-beam irradiation.

Development of a high-efficiency, gas-fired, absorption heat pump for residental and small-commercial applications

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

Phillips, B.A.

1990-09-01

The purpose of the total project is to develop a gas-fired absorption heat pump for residential and small-commercial applications that will produce at least 1.6 Btu of heating and 0.7 Btu of cooling per Btu of heat content in the gas being burned. The primary technology advances that can be used to attain the new goals are higher efficiency cycles, increased flue efficiency, and better fluids. Flue efficiency technology is well developed, and fan-assisted combustion systems with condensing heat exchangers can limit flue and insulation losses to the 10% range. If this 10% loss assumption is made, the resulting targetmore » cycle COPs are 1.78 in heating mode and 0.78 in cooling mode at the ARI rating conditions. The objective of Phase 1 was to analyze working fluids and absorption-cycle concepts that are capable of performing at the target COPs and are potentially competitive with existing space-conditioning products in cost, operating life, and reliability. Six advanced cycles were evaluated with ammonia/water as the fluid pair. Then additional analysis was performed with other fluid pairs to determine whether cycle ranking would change depending on which fluid was used. It was concluded that the preferred cycle/fluid was the generator-absorber heat exchange (GAX) cycle using ammonia/water as the fluid pair. A cost estimate made by an independent manufacturing engineering firm for a residential heat pump based on the cycle/fluid combination determined that the GAX heat pump could be cost competitive with existing products. 20 refs., 28 figs., 2 tabs.« less

Multistage quantum absorption heat pumps.

PubMed

Correa, Luis A

2014-04-01

It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

An exact solution on unsteady MHD free convection chemically reacting silver nanofluid flow past an exponentially accelerated vertical plate through porous medium

NASA Astrophysics Data System (ADS)

Kumaresan, E.; Vijaya Kumar, A. G.; Rushi Kumar, B.

2017-11-01

This article studies, an exact solution of unsteady MHD free convection boundary-layer flow of a silver nanofluid past an exponentially accelerated moving vertical plate through aporous medium in the presence of thermal radiation, transverse applied amagnetic field, radiation absorption and Heat generation or absorption with chemical reaction are investigated theoretically. We consider nanofluids contain spherical shaped nanoparticle of silverwith a nanoparticle volume concentration range smaller than or equal to 0.04. This phenomenon is modeled in the form of partial differential equations with initial boundary conditions. Some suitable dimensional variables are introduced. The corresponding dimensionless equations with boundary conditions are solved by using Laplace transform technique. The exact solutions for velocity, energy, and species are obtained, also the corresponding numerical values of nanofluid velocity, temperature and concentration profiles are represented graphically. The expressions for skin friction coefficient, the rate of heat transfer and mass transfer are derived. The present study finds applications involving heat transfer, enhancement of thermal conductivity and other applications like transportation, industrial cooling applications, heating buildings and reducing pollution, energy applications and solar absorption. The effect of heat transfer is found to be more pronounced in a silver-water nanofluid than in the other nanofluids.

Attosecond transient absorption instrumentation for thin film materials: Phase transitions, heat dissipation, signal stabilization, timing correction, and rapid sample rotation.

PubMed

Jager, Marieke F; Ott, Christian; Kaplan, Christopher J; Kraus, Peter M; Neumark, Daniel M; Leone, Stephen R

2018-01-01

We present an extreme ultraviolet (XUV) transient absorption apparatus tailored to attosecond and femtosecond measurements on bulk solid-state thin-film samples, specifically when the sample dynamics are sensitive to heating effects. The setup combines methodology for stabilizing sub-femtosecond time-resolution measurements over 48 h and techniques for mitigating heat buildup in temperature-dependent samples. Single-point beam stabilization in pump and probe arms and periodic time-zero reference measurements are described for accurate timing and stabilization. A hollow-shaft motor configuration for rapid sample rotation, raster scanning capability, and additional diagnostics are described for heat mitigation. Heat transfer simulations performed using a finite element analysis allow comparison of sample rotation and traditional raster scanning techniques for 100 Hz pulsed laser measurements on vanadium dioxide, a material that undergoes an insulator-to-metal transition at a modest temperature of 340 K. Experimental results are presented confirming that the vanadium dioxide (VO 2 ) sample cannot cool below its phase transition temperature between laser pulses without rapid rotation, in agreement with the simulations. The findings indicate the stringent conditions required to perform rigorous broadband XUV time-resolved absorption measurements on bulk solid-state samples, particularly those with temperature sensitivity, and elucidate a clear methodology to perform them.

Attosecond transient absorption instrumentation for thin film materials: Phase transitions, heat dissipation, signal stabilization, timing correction, and rapid sample rotation

NASA Astrophysics Data System (ADS)

Jager, Marieke F.; Ott, Christian; Kaplan, Christopher J.; Kraus, Peter M.; Neumark, Daniel M.; Leone, Stephen R.

2018-01-01

We present an extreme ultraviolet (XUV) transient absorption apparatus tailored to attosecond and femtosecond measurements on bulk solid-state thin-film samples, specifically when the sample dynamics are sensitive to heating effects. The setup combines methodology for stabilizing sub-femtosecond time-resolution measurements over 48 h and techniques for mitigating heat buildup in temperature-dependent samples. Single-point beam stabilization in pump and probe arms and periodic time-zero reference measurements are described for accurate timing and stabilization. A hollow-shaft motor configuration for rapid sample rotation, raster scanning capability, and additional diagnostics are described for heat mitigation. Heat transfer simulations performed using a finite element analysis allow comparison of sample rotation and traditional raster scanning techniques for 100 Hz pulsed laser measurements on vanadium dioxide, a material that undergoes an insulator-to-metal transition at a modest temperature of 340 K. Experimental results are presented confirming that the vanadium dioxide (VO2) sample cannot cool below its phase transition temperature between laser pulses without rapid rotation, in agreement with the simulations. The findings indicate the stringent conditions required to perform rigorous broadband XUV time-resolved absorption measurements on bulk solid-state samples, particularly those with temperature sensitivity, and elucidate a clear methodology to perform them.

Design, evaluation and recommedation effort relating to the modification of a residential 3-ton absorption cycle cooling unit for operation with solar energy

NASA Technical Reports Server (NTRS)

Merrick, R. H.; Anderson, P. P.

1973-01-01

The possible use of solar energy powered absorption units to provide cooling and heating of residential buildings is studied. Both, the ammonia-water and the water-lithium bromide cycles, are considered. It is shown that the air cooled ammonia water unit does not meet the criteria for COP and pump power on the cooling cycle and the heat obtained from it acting as a heat pump is at too low a temperature. If the ammonia machine is water cooled it will meet the design criteria for cooling but can not supply the heating needs. The water cooled lithium bromide unit meets the specified performance for cooling with appreciably lower generator temperatures and without a mechanical solution pump. It is recommeded that in the demonstration project a direct expansion lithium bromide unit be used for cooling and an auxiliary duct coil using the solar heated water be employed for heating.

Improved thermal storage material for portable life support systems

NASA Technical Reports Server (NTRS)

Kellner, J. D.

1975-01-01

The availability of thermal storage materials that have heat absorption capabilities substantially greater than water-ice in the same temperature range would permit significant improvements in performance of projected portable thermal storage cooling systems. A method for providing increased heat absorption by the combined use of the heat of solution of certain salts and the heat of fusion of water-ice was investigated. This work has indicated that a 30 percent solution of potassium bifluoride (KHF2) in water can absorb approximately 52 percent more heat than an equal weight of water-ice, and approximately 79 percent more heat than an equal volume of water-ice. The thermal storage material can be regenerated easily by freezing, however, a lower temperature must be used, 261 K as compared to 273 K for water-ice. This work was conducted by the United Aircraft Research Laboratories as part of a program at Hamilton Standard Division of United Aircraft Corporation under contract to NASA Ames Research Center.

Diagnosing the plasma nonuniformity in an iron opacity experiment by spatially resolved Al 1s-2p absorption spectroscopy

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

Zhang Xiaoding; Research Center of Laser Fusion, P. O. Box 919-986, Mianyang 621900; Zhang Jiyan

Generating a well-characterized hot-dense sample is of great importance to high quality opacity measurements. In this paper, we report on an experimental investigation of the plasma nonuniformity in a radiatively heated iron opacity sample by spatially resolved Al 1s-2p absorption spectroscopy. The iron sample was tamped by plastic at both sides and was heated by thermal x-ray radiation generated in a gold Hohlraum, and an Al layer attached to it was used as a tracer for temperature diagnosis. Spatially resolved 1s-2p transition absorption spectra of the Al tracer were measured by the technique of point-projection-spectroscopy, and temperatures in the samplemore » were obtained by comparing the measured spectra with detailed-term-accounting model calculations, with the density of the sample deduced using a combination of side-on radiography and radiative hydrodynamic simulation. The results showed the existence of axial temperature nonuniformity in the sample, and these temperature variations have been used to explain the shift of iron 2p-3d transition absorption feature along the axial direction of the Hohlraum used to heat the sample successfully.« less

Gas-heat-pump development

NASA Astrophysics Data System (ADS)

Creswick, F. A.

Incentives for the development of gas heat pumps are discussed. Technical progress made on several promising technologies was reviewed. The status of development of gas-engine-driven heat pumps, the absorption cycle for the near- and long-term gas heat pump systems, the Stirling engine, the small Rankine-cycle engines, and gas-turbine-driven heat pump systems were briefly reviewed. Progress in the US, Japan, and Europe is noted.

Al 1s-2p absorption spectroscopy of shock-wave heating and compression in laser-driven planar foil

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

Sawada, H.; Regan, S. P.; Radha, P. B.

Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (T{sub e}{approx}10-40 eV, {rho}{approx}3-11 g/cm{sup 3}) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10{sup 14}-10{sup 15} W/cm{sup 2} and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4-1.7 keV. The laser ablation process launches 10-70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectramore » were analyzed using the atomic physic code PRISMSPECT to infer T{sub e} and {rho} in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f=0.06 and f=0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f=0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.« less

Al 1s-2p Absorption Spectroscopy of Shock-Wave Heating and Compression in Laser-Driven Planar Foil

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

Sawada, H.; Regan, S.P.; Radha, P.B.

Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (Te ~ 10–40 eV, rho ~ 3–11 g/cm^3) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10^14–10^15 W/cm^2 and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4–1.7 keV. The laser ablation process launches 10–70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectra weremore » analyzed using the atomic physic code PRISMSPECT to infer Te and rho in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f =0.06 and f =0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f = 0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.« less

Nanofibrous membrane-based absorption refrigeration system

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

Isfahani, RN; Sampath, K; Moghaddam, S

2013-12-01

This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature,more » and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.« less

Solid oxide fuel cell/gas turbine trigeneration system for marine applications

NASA Astrophysics Data System (ADS)

Tse, Lawrence Kar Chung; Wilkins, Steven; McGlashan, Niall; Urban, Bernhard; Martinez-Botas, Ricardo

2011-03-01

Shipping contributes 4.5% to global CO2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost. This paper investigates the feasibility of combining a SOFC-GT system and an absorption heat pump (AHP) in a trigeneration system to drive the heating ventilation and air conditioning (HVAC) and electrical base-load systems. A thermodynamic model is used to simulate the system, with various configurations and cooling loads. Measurement of actual yacht performance data forms the basis of this system simulation. It is found that for the optimum configuration using a double effect absorption chiller in Ship 1, the net electric power increases by 47% relative to the electrical power available for a conventional SOFC-GT-HVAC system. This is due to more air cooled to a lower temperature by absorption cooling; hence less electrical cooling by the conventional HVAC unit is required. The overall efficiency is 12.1% for the conventional system, 34.9% for the system with BROAD single effect absorption chiller, 43.2% for the system with double effect absorption chiller. This shows that the overall efficiency of a trigeneration system is far higher when waste heat recovery happens. The desiccant wheel hardly reduces moisture from the outdoor air due to a relative low mass flow rate of fuel cell exhaust available to dehumidify a very large mass flow rate of HVAC air, Hence, desiccant wheel is not recommended for this application.

Theoretical modeling on the laser-induced phase deformation of liquid crystal optical phased shifter

NASA Astrophysics Data System (ADS)

Zhou, Zhuangqi; Wang, Xiangru; Zhuo, Rusheng; He, Xiaoxian; Wu, Liang; Wang, Xiaolin; Tan, Qinggui; Qiu, Qi

2018-03-01

To improve the working condition of liquid crystal phase shifter on incident laser power, a theoretical model on laser induced phase distortion is built on the physics of heat deposition and heat transfer. Four typical factors (absorption, heat sink structure, cooling fluid rate, and substrate) are analyzed to evaluate the influence of phase distortion when a relative high-power laser is pumped into the liquid crystal phase shifter. Flow rate of cooling fluid and heat sink structure are the most important two factors on improving the limit of incident laser power. Meanwhile, silicon wafer is suggested to replace the back glass contacting the heat sink, because of its higher heat transfer coefficient. If the device is fabricated on the conditions that: the total absorption is 5% and it has a strong heat sink structure with a flow rate of 0.01 m/s, when the incident laser power is 110W, the laser-induced phase deformation on the center is diminished to be less than 0.06, and the maximum temperature increase on the center is less than 1K degree.

Low-cost thin-film absorber/evaporator for an absorption chiller. Final report, May 1992-April 1993

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

Lowenstein, A.; Sibilia, M.

1993-04-01

The feasibility of making the absorber and evaporator of a small lithium-bromide absorption chiller from thin plastic films was studied. Tests were performed to measure (1) pressure limitations for a plastic thin-film heat exchanger, (2) flow pressure-drop characteristics, (3) air permeation rates across the plastic films, and (4) creep characteristics of the plastic films. Initial tests were performed on heat exchangers made of either low-density polyethylene (LDPE), high-density polyethylene (HDPE), or a LDPE/HDPE blend. While initial designs for the heat exchanger failed at internal pressures of only 5 to 6 psi, the final design could withstand pressures of 34 psi.

Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

PubMed

Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

2015-10-06

A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

PubMed Central

Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

2015-01-01

A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

DOE PAGES

Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

2015-09-21

A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. In this paper, we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. Whenmore » placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Lastly, our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.« less

New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

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

Qu, Ming; Abdelaziz, Omar; Yin, Hongxi

2014-11-01

Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150 200 C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50 60more » C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural gas boilers for applications with process fluid return temperatures higher than or close to the dew point of the water vapor in the flue gas.« less

Laser production and heating of plasma for MHD application

NASA Technical Reports Server (NTRS)

Jalufka, N. W.

1988-01-01

Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

Absorption spectra measurements of the x-ray radiation heated SiO2 aerogel plasma in 'dog-bone' targets irradiated by high power laser pulses

NASA Astrophysics Data System (ADS)

Zhang, Y.; Dong, Q.-L.; Wang, S.-J.; Li, Y.-T.; Zhang, J.; Wei, H.-G.; Shi, J.-R.; Zhao, G.; Zhang, J.-Y.; Wen, T.-S.; Zhang, W.-H.; Hu, X.; Liu, S.-Y.; Ding, Y.-K.; Zhang, L.; Tang, Y.-J.; Zhang, B.-H.; Zheng, Z.-J.; Nishimura, H.; Fujioka, S.; Takabe, H.

2008-05-01

We studied the opacity effect of the SiO2 aerogel plasma heated by x-ray radiation produced by high power laser pulses irradiating the inner surface of golden 'dog-bone' targets. The PET crystal spectrometer was used to measure the absorption spectra of the plasmas in the range from 6.4 Å to 7.4 Å, among which the line emissions involving the K shell of Si ions from He-like to neutral atom were located. The experimental results were analyzed with Detailed-Level-Accounting method. As the plasma temperature increased, the characteristic lines of highly ionized ions gradually dominated the absorption spectrum.

Moisture absorption and bakeout characteristics of rigid-flexible multilayer printed wiring boards

NASA Astrophysics Data System (ADS)

Lula, J. W.

1991-01-01

Moisture absorption and bakeout characteristics of rigid flexible printed wiring boards were determined. It was found that test specimens had absorbed 0.95 weight percent moisture when equilibrated to a 50 percent RH, 25 C environment. Heating those equilibrated specimens in a 120 C static air oven removed 92 percent of this absorbed moisture in 24 h. Heating the samples in a 80 C static air oven removed only 64 percent of the absorbed moisture at the end of 24 h. A 120 C vacuum bake removed moisture at essentially the same rate with parylene slowed the absorption rate by approximately 50 percent but did not appreciably affect the equilibrium moisture content or the drying rate.

Spatial nonlinear absorption of Alfven waves by dissipative plasma taking account bremsstrahlung

NASA Astrophysics Data System (ADS)

Taiurskii, A. A.; Gavrikov, M. B.

2016-10-01

We study numerically the nonlinear absorption of a plane Alfven wave falling on the stationary boundary of dissipative plasma. This absorption is caused by such factors as the magnetic viscosity, hydrodynamic viscosity, and thermal conductivity of electrons and ions, bremsstrahlung and energy exchange between plasma components. The relevance of this investigation is due to some works, published in 2011, with regard to the heating mechanism of the solar corona and solar wind generation as a result of the absorption of plasma Alfven waves generated in the lower significantly colder layers of the Sun. Numerical analysis shows that the absorption of Alfven waves occurs at wavelengths of the order of skin depth, in which case the classical MHD equations are inapplicable. Therefore, our research is based on equations of two-fluid magnetohydrodynamics that take into account the inertia of the electrons. The implicit difference scheme proposed here for calculating plane-parallel flows of two-fluid plasma reveals a number of important patterns of absorption and thus allows us to study the dependence of the absorption on the Alfven wave frequency and the electron thermal conductivity and viscosity, as well as to evaluate the depth and the velocity of plasma heating during the penetration of Alfven waves interacting with dissipative plasma.

Collisionless absorption of intense laser radiation in nanoplasma

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

Zaretsky, D F; Korneev, Philipp A; Popruzhenko, Sergei V

The rate of linear collisionless absorption of an electromagnetic radiation in a nanoplasma - classical electron gas localised in a heated ionised nanosystem (thin film or cluster) irradiated by an intense femtosecond laser pulse - is calculated. The absorption is caused by the inelastic electron scattering from the self-consistent potential of the system in the presence of a laser field. The effect proves to be appreciable because of a small size of the systems. General expressions are obtained for the absorption rate as a function of the parameters of the single-particle self-consistent potential and electron distribution function in the regimemore » linear in field. For the simplest cases, where the self-consistent field is created by an infinitely deep well or an infinite charged plane, closed analytic expressions are obtained for the absorption rate. Estimates presented in the paper demonstrate that, over a wide range of the parameters of laser pulses and nanostructures, the collisionless mechanism of heating electron subsystem can be dominant. The possibility of experimental observation of the collisionless absorption of intense laser radiation in nanoplasma is also discussed. (interaction of laser radiation with matter)« less

Thermal tuning of infrared resonant absorbers based on hybrid gold-VO{sub 2} nanostructures

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

Kocer, Hasan; Department of Electrical Engineering, Turkish Military Academy, 06654 Ankara; Butun, Serkan

2015-04-20

Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO{sub 2}) nanostructure arrays. Absorption intensity is tuned from 90% to 20%more » and 96% to 32% using hybrid gold-VO{sub 2} nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO{sub 2} (68 °C). Phase change materials such as VO{sub 2} deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.« less

Gas Fride Heat Pumps : The Present and Future

NASA Astrophysics Data System (ADS)

Kurosawa, Shigekichi; Ogura, Masao

In japan techniques for saving energy is an important goal since energy resources such as oil and nuclear power are limited. Recently gas fired absorption heat pumps and gas engine driven heat pumps have been installed in facilifies such as hotels, swimming pools and offices.
In this article recent techniques, applications and future aspects for gas fired heat pumps are explained.

Thermal control systems for low-temperature heat rejection on a lunar base

NASA Technical Reports Server (NTRS)

Sridhar, K. R.; Gottmann, Matthias

1992-01-01

In this report, Rankine-cycle heat pumps and absorption heat pumps (ammonia-water and lithium bromide-water) have been analyzed and optimized for a lunar base cooling load of 100 kW. For the Rankine cycle, a search of several commonly used commercial refrigerants provided R11 and R717 as possible working fluids. Hence, the Rankine-cycle analysis has been performed for both R11 and R717. Two different configurations were considered for the system--one in which the heat pump is directly connected to the rejection loop and another in which a heat exchanger connects the heat pump to the rejection loop. For a marginal increase in mass, the decoupling of the rejection loop and the radiator from the heat pump provides greater reliability of the system and better control. Hence, the decoupled system is the configuration of choice. The optimal TCS mass for a 100 kW cooling load at 270 K was 5940 kg at a radiator temperature of 362 K. R11 was the working fluid in the heat pump, and R717 was the transport fluid in the rejection loop. Two TCS's based on an absorption-cycle heat pump were considered, one with an ammonia-water mixture and the other with a lithium bromide-water mixture as the working fluid. A complete cycle analysis was performed for these systems. The system components were approximated as heat exchangers with no internal pressure drop for the mass estimate. This simple approach underpredicts the mass of the systems, but is a good 'optimistic' first approximation to the TCS mass in the absence of reliable component mass data. The mass estimates of the two systems reveal that, in spite of this optimistic estimate, the absorption heat pumps are not competitive with the Rankine-cycle heat pumps. Future work at the systems level will involve similar analyses for the Brayton- and Stirling-cycle heat pumps. The analyses will also consider the operation of the pump under partial-load conditions. On the component level, a capillary evaporator will be designed, built, and tested in order to investigate its suitability in lunar base TCS and microgravity two-phase applications.

Absorptive coating for aluminum solar panels

NASA Technical Reports Server (NTRS)

Desmet, D.; Jason, A.; Parr, A.

1979-01-01

Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

Water adsorption on a liquid surface.

PubMed

Lovelock, Kevin R J; Smith, Emily F; Deyko, Alexey; Villar-Garcia, Ignacio J; Licence, Peter; Jones, Robert G

2007-12-14

Monolayer adsorption of water onto an ionic liquid in ultra-high vacuum has been demonstrated, revealing a heat of adsorption which exceeds the heat of absorption into the bulk liquid by approximately 40 kJ mol(-1).

Solar Spectral Radiative Forcing During the Southern African Regional Science Initiative

NASA Technical Reports Server (NTRS)

Pilewskie, P.; Pommier, J.; Bergstrom, R.; Gore, W.; Howard, S.; Rabbette, M.; Schmid, B.; Hobbs, P. V.; Tsay, S. C.

2003-01-01

During the dry season component of the Southern African Regional Science Initiative (SAFARI) in late winter 2000, the net solar spectral irradiance was measured at flight levels throughout biomass burning haze layers. From these measurements, the flux divergence, fractional absorption, instantaneous heating rate, and absorption efficiency were derived. Two cases are examined: on 24 August 2000 off the coast of Mozambique in the vicinity of Inhaca Island and on 6 September 2000 in a very thick continental haze layer over Mongu, Zambia. The measured absolute absorption was substantially higher for the case over Mongu where the measured midvisible optical depth exceeded unity. Instantaneous heating from aerosol absorption was 4 K d(sup -1) over Mongu, Zambia and 1.5 K d(sup -1) near Inhaca Island, Mozambique. However, the spectral absorption efficiency was nearly identical for both cases. Although the observations over Inhaca Island preceded the river of smoke from the southern African continent by nearly 2 weeks, the evidence here suggests a continental influence in the lower tropospheric aerosol far from source regions of burning.

Absorption Refrigeration Cycles with Ammonia-Ionic Liquid Working Pairs Studied by Molecular Simulation.

PubMed

Becker, Tim M; Wang, Meng; Kabra, Abhishek; Jamali, Seyed Hossein; Ramdin, Mahinder; Dubbeldam, David; Infante Ferreira, Carlos A; Vlugt, Thijs J H

2018-04-18

For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an alternative computational approach. The required thermodynamic properties, i.e., solubility, heat capacity, and heat of absorption, are determined via molecular simulations. These properties are used in a model of the absorption refrigeration cycle to estimate the circulation ratio and the coefficient of performance. We selected two ionic liquids as absorbents: [emim][Tf 2 N], and [emim][SCN]. As refrigerant NH 3 was chosen due to its favorable operating range. The results are compared to the traditional approach in which parameters of a thermodynamic model are fitted to reproduce experimental data. The work shows that simulations can be used to predict the required thermodynamic properties to estimate the performance of absorption refrigeration cycles. However, high-quality force fields are required to accurately predict the cycle performance.

Absorption Refrigeration Cycles with Ammonia–Ionic Liquid Working Pairs Studied by Molecular Simulation

PubMed Central

2018-01-01

For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an alternative computational approach. The required thermodynamic properties, i.e., solubility, heat capacity, and heat of absorption, are determined via molecular simulations. These properties are used in a model of the absorption refrigeration cycle to estimate the circulation ratio and the coefficient of performance. We selected two ionic liquids as absorbents: [emim][Tf2N], and [emim][SCN]. As refrigerant NH3 was chosen due to its favorable operating range. The results are compared to the traditional approach in which parameters of a thermodynamic model are fitted to reproduce experimental data. The work shows that simulations can be used to predict the required thermodynamic properties to estimate the performance of absorption refrigeration cycles. However, high-quality force fields are required to accurately predict the cycle performance. PMID:29749996

Three-Dimensional Flow of an Oldroyd-B Fluid with Variable Thermal Conductivity and Heat Generation/Absorption

PubMed Central

Shehzad, Sabir Ali; Alsaedi, Ahmed; Hayat, Tasawar; Alhuthali, M. Shahab

2013-01-01

This paper looks at the series solutions of three dimensional boundary layer flow. An Oldroyd-B fluid with variable thermal conductivity is considered. The flow is induced due to stretching of a surface. Analysis has been carried out in the presence of heat generation/absorption. Homotopy analysis is implemented in developing the series solutions to the governing flow and energy equations. Graphs are presented and discussed for various parameters of interest. Comparison of present study with the existing limiting solution is shown and examined. PMID:24223780

Apparatus for experimental investigation of aerodynamic radiation with absorption by ablation products

NASA Technical Reports Server (NTRS)

Wells, W. L.; Snow, W. L.

1977-01-01

A description is given and calibration procedures are presented for an apparatus that is used to simulate aerodynamic radiant heating during planetary entry. The primary function of the apparatus is to simulate the spectral distribution of shock layer radiation and to determine absorption effects of simulated ablation products which are injected into the stagnation region flow field. An electric arc heater is used to heat gas mixtures that represent the planetary atmospheres of interest. Spectral measurements are made with a vacuum ultraviolet scanning monochromator.

Gold nanostars as thermoplasmonic nanoparticles for optical heating.

PubMed

Rodríguez-Oliveros, R; Sánchez-Gil, José A

2012-01-02

Gold nanostars are theoretically studied as efficient thermal heaters at their corresponding localized surface-plasmon resonances (LSPRs). Numerical calculations are performed through the 3D Green's Theorem method to obtain the absorption and scattering cross sections for Au nanoparticles with star-like shape of varying symmetry and tip number. Their unique thermoplasmonic properties, with regard to their (red-shifted) LSPR wavelentgh, (∼ 30-fold increase) steady-state temperature, and scattering/absorption cross section ratios, make them specially suitable for optical heating and in turn for cancer thermal therapy.

Flameless Atomic Absorption Spectroscopy: Effects of Nitrates and Sulfates.

DTIC Science & Technology

1980-05-01

ATTACHED DDJ~P 1413 EDITION 01 INO, 6 5 IabSoLEr J UjN!LbAa~ A- i SELU 0 IONOF I tG 651 J Flameless Atomic Absorption Spectroscopy: Effects of Nitrates...analytical techniques, flameless atomic absorption is subject to matrix or interference effects. Upon heating, nitrate and sulfate salts decompose to...Eklund and J.E. Smith, Anal Chem, 51, 1205 (1979) R.H. Eklund and J.A. Holcombe, Anal Chim. Acta, 109, 97 (1979) FLAMELESS ATOMIC ABSORPTION

Full-wave simulations of ICRF heating regimes in toroidal plasma with non-Maxwellian distribution functions

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

Bertelli, N.; Valeo, E. J.; Green, D. L.

At the power levels required for significant heating and current drive in magnetically-confined toroidal plasma, modification of the particle distribution function from a Maxwellian shape is likely (Stix 1975 Nucl. Fusion 15 737), with consequent changes in wave propagation and in the location and amount of absorption. In order to study these effects computationally, both the finite-Larmor-radius and the high-harmonic fast wave (HHFW), versions of the full-wave, hot-plasma toroidal simulation code TORIC (Brambilla 1999 Plasma Phys. Control. Fusion 41 1 and Brambilla 2002 Plasma Phys. Control. Fusion 44 2423), have been extended to allow the prescription of arbitrary velocity distributionsmore » of the form f(v(parallel to), v(perpendicular to) , psi, theta). For hydrogen (H) minority heating of a deuterium (D) plasma with anisotropic Maxwellian H distributions, the fractional H absorption varies significantly with changes in parallel temperature but is essentially independent of perpendicular temperature. On the other hand, for HHFW regime with anisotropic Maxwellian fast ion distribution, the fractional beam ion absorption varies mainly with changes in the perpendicular temperature. The evaluation of the wave-field and power absorption, through the full wave solver, with the ion distribution function provided by either a Monte-Carlo particle and Fokker-Planck codes is also examined for Alcator C-Mod and NSTX plasmas. Non-Maxwellian effects generally tend to increase the absorption with respect to the equivalent Maxwellian distribution.« less

Full-wave simulations of ICRF heating regimes in toroidal plasmas with non-Maxwellian distribution functions

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

Bertelli, N.; Valeo, E.J.; Green, D.L.

At the power levels required for significant heating and current drive in magnetically-confined toroidal plasma, modification of the particle distribution function from a Maxwellian shape is likely [T. H. Stix, Nucl. Fusion, 15 737 (1975)], with consequent changes in wave propagation and in the location and amount of absorption. In order to study these effects computationally, both the finite-Larmor-radius and the high-harmonic fast wave (HHFW), versions of the full-wave, hot-plasma toroidal simulation code TORIC [M. Brambilla, Plasma Phys. Control. Fusion 41, 1 (1999) and M. Brambilla, Plasma Phys. Control. Fusion 44, 2423 (2002)], have been extended to allow the prescriptionmore » of arbitrary velocity distributions of the form f(v||, v_perp, psi , theta). For hydrogen (H) minority heating of a deuterium (D) plasma with anisotropic Maxwellian H distributions, the fractional H absorption varies significantly with changes in parallel temperature but is essentially independent of perpendicular temperature. On the other hand, for HHFW regime with anisotropic Maxwellian fast ion distribution, the fractional beam ion absorption varies mainly with changes in the perpendicular temperature. The evaluation of the wave-field and power absorption, through the full wave solver, with the ion distribution function provided by either aMonte-Carlo particle and Fokker-Planck codes is also examined for Alcator C-Mod and NSTX plasmas. Non-Maxwellian effects generally tends to increase the absorption with respect to the equivalent Maxwellian distribution.« less

Remote laser evaporative molecular absorption spectroscopy

NASA Astrophysics Data System (ADS)

Hughes, Gary B.; Lubin, Philip; Cohen, Alexander; Madajian, Jonathan; Kulkarni, Neeraj; Zhang, Qicheng; Griswold, Janelle; Brashears, Travis

2016-09-01

We describe a novel method for probing bulk molecular and atomic composition of solid targets from a distant vantage. A laser is used to melt and vaporize a spot on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption occurs as the blackbody radiation passes through the ejected plume. Bulk molecular and atomic composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected plume. The proposed method is distinct from current stand-off approaches to composition analysis, such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes target material and observes emission spectra to determine bulk atomic composition. Initial simulations of absorption profiles with laser heating show great promise for Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy. The method is well-suited for exploration of cold solar system targets—asteroids, comets, planets, moons—such as from a spacecraft orbiting the target. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole or trench, and shallow subsurface composition profiling is possible. This paper describes system concepts for implementing the proposed method to probe the bulk molecular composition of an asteroid from an orbiting spacecraft, including laser array, photovoltaic power, heating and ablation, plume characteristics, absorption, spectrometry and data management.

Full-wave simulations of ICRF heating regimes in toroidal plasma with non-Maxwellian distribution functions

NASA Astrophysics Data System (ADS)

Bertelli, N.; Valeo, E. J.; Green, D. L.; Gorelenkova, M.; Phillips, C. K.; Podestà, M.; Lee, J. P.; Wright, J. C.; Jaeger, E. F.

2017-05-01

At the power levels required for significant heating and current drive in magnetically-confined toroidal plasma, modification of the particle distribution function from a Maxwellian shape is likely (Stix 1975 Nucl. Fusion 15 737), with consequent changes in wave propagation and in the location and amount of absorption. In order to study these effects computationally, both the finite-Larmor-radius and the high-harmonic fast wave (HHFW), versions of the full-wave, hot-plasma toroidal simulation code TORIC (Brambilla 1999 Plasma Phys. Control. Fusion 41 1 and Brambilla 2002 Plasma Phys. Control. Fusion 44 2423), have been extended to allow the prescription of arbitrary velocity distributions of the form f≤ft({{v}\\parallel},{{v}\\bot},\\psi,θ \\right) . For hydrogen (H) minority heating of a deuterium (D) plasma with anisotropic Maxwellian H distributions, the fractional H absorption varies significantly with changes in parallel temperature but is essentially independent of perpendicular temperature. On the other hand, for HHFW regime with anisotropic Maxwellian fast ion distribution, the fractional beam ion absorption varies mainly with changes in the perpendicular temperature. The evaluation of the wave-field and power absorption, through the full wave solver, with the ion distribution function provided by either a Monte-Carlo particle and Fokker-Planck codes is also examined for Alcator C-Mod and NSTX plasmas. Non-Maxwellian effects generally tend to increase the absorption with respect to the equivalent Maxwellian distribution.

Full-wave simulations of ICRF heating regimes in toroidal plasma with non-Maxwellian distribution functions

DOE PAGES

Bertelli, N.; Valeo, E. J.; Green, D. L.; ...

2017-04-03

At the power levels required for significant heating and current drive in magnetically-confined toroidal plasma, modification of the particle distribution function from a Maxwellian shape is likely (Stix 1975 Nucl. Fusion 15 737), with consequent changes in wave propagation and in the location and amount of absorption. In order to study these effects computationally, both the finite-Larmor-radius and the high-harmonic fast wave (HHFW), versions of the full-wave, hot-plasma toroidal simulation code TORIC (Brambilla 1999 Plasma Phys. Control. Fusion 41 1 and Brambilla 2002 Plasma Phys. Control. Fusion 44 2423), have been extended to allow the prescription of arbitrary velocity distributionsmore » of the form f(v(parallel to), v(perpendicular to) , psi, theta). For hydrogen (H) minority heating of a deuterium (D) plasma with anisotropic Maxwellian H distributions, the fractional H absorption varies significantly with changes in parallel temperature but is essentially independent of perpendicular temperature. On the other hand, for HHFW regime with anisotropic Maxwellian fast ion distribution, the fractional beam ion absorption varies mainly with changes in the perpendicular temperature. The evaluation of the wave-field and power absorption, through the full wave solver, with the ion distribution function provided by either a Monte-Carlo particle and Fokker-Planck codes is also examined for Alcator C-Mod and NSTX plasmas. Non-Maxwellian effects generally tend to increase the absorption with respect to the equivalent Maxwellian distribution.« less

Measurement of dielectric properties of whole and ground chicken breast meat over the frequency range from 500 MHz to 50 GHz

USDA-ARS?s Scientific Manuscript database

The dielectric properties of food greatly influence its interaction with RF and MW electromagnetic fields and subsequently determine the absorption of microwave energy and consequent heating behavior of food materials in microwave heating and processing applications. Microwave heating is usually re...

Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

USDA-ARS?s Scientific Manuscript database

With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

Solar-Heated and Cooled Office Building--Columbus, Ohio

NASA Technical Reports Server (NTRS)

1982-01-01

Final report documents solar-energy system installed in office building to provide space heating, space cooling and domestic hot water. Collectors mounted on roof track Sun and concentrate rays on fluid-circulating tubes. Collected energy is distributed to hot-water-fired absorption chiller and space-heating and domestic-hot-water preheating systems.

Mixed convection and heat generation/absorption aspects in MHD flow of tangent-hyperbolic nanoliquid with Newtonian heat/mass transfer

NASA Astrophysics Data System (ADS)

Qayyum, Sajid; Hayat, Tasawar; Shehzad, Sabir Ali; Alsaedi, Ahmed

2018-03-01

This article concentrates on the magnetohydrodynamic (MHD) stagnation point flow of tangent hyperbolic nanofluid in the presence of buoyancy forces. Flow analysis caused due to stretching surface. Characteristics of heat transfer are examined under the influence of thermal radiation and heat generation/absorption. Newtonian conditions for heat and mass transfer are employed. Nanofluid model includes Brownian motion and thermophoresis. The governing nonlinear partial differential systems of the problem are transformed into a systems of nonlinear ordinary differential equations through appropriate variables. Impact of embedded parameters on the velocity, temperature and nanoparticle concentration fields are presented graphically. Numerical computations are made to obtain the values of skin friction coefficient, local Nusselt and Sherwood numbers. It is concluded that velocity field enhances in the frame of mixed convection parameter while reverse situation is observed due to power law index. Effect of Brownian motion parameter on the temperature and heat transfer rate is quite reverse. Moreover impact of solutal conjugate parameter on the concentration and local Sherwood number is quite similar.

Absorption cooling sources atmospheric emissions decrease by implementation of simple algorithm for limiting temperature of cooling water

NASA Astrophysics Data System (ADS)

Wojdyga, Krzysztof; Malicki, Marcin

2017-11-01

Constant strive to improve the energy efficiency forces carrying out activities aimed at reduction of energy consumption hence decreasing amount of contamination emissions to atmosphere. Cooling demand, both for air-conditioning and process cooling, plays an increasingly important role in the balance of Polish electricity generation and distribution system in summer. During recent years' demand for electricity during summer months has been steadily and significantly increasing leading to deficits of energy availability during particularly hot periods. This causes growing importance and interest in trigeneration power generation sources and heat recovery systems producing chilled water. Key component of such system is thermally driven chiller, mostly absorption, based on lithium-bromide and water mixture. Absorption cooling systems also exist in Poland as stand-alone systems, supplied with heating from various sources, generated solely for them or recovered as waste or useless energy. The publication presents a simple algorithm, designed to reduce the amount of heat for the supply of absorption chillers producing chilled water for the purposes of air conditioning by reducing the temperature of the cooling water, and its impact on decreasing emissions of harmful substances into the atmosphere. Scale of environmental advantages has been rated for specific sources what enabled evaluation and estimation of simple algorithm implementation to sources existing nationally.

Tailoring the light absorption of Ag-PZT thin films by controlling the growth of hexagonal- and cubic-phase Ag nanoparticles

NASA Astrophysics Data System (ADS)

Hu, Tao; Wang, Zongrong; Ma, Ning; Du, Piyi

2017-12-01

PbZr0.52Ti0.48O3 thin films containing hexagonal and cubic Ag nanoparticles (Ag NPs) of various sizes were prepared using the sol-gel technique. During the aging process, Ag ions were photo-reduced to form hexagonal Ag NPs. These NPs were uniform in size, and their uniformity was maintained in the thin films during the heat treatment process. Both the total volume and average size of the hexagonal Ag NPs increased with an increasing Ag ion concentration from 0.02 to 0.08 mol l-1. Meanwhile, the remaining Ag ions were reduced to form unstable Ag-Pb alloy particles with Pb ions during the early heating stage. During subsequent heat treatment, these alloys decomposed to form cubic Ag NPs in the thin films. The absorption range of the thin films, quantified as the full width at half maximum in the ultraviolet-visible absorption spectrum, expanded from 6.3 × 1013 Hz (390-425 nm) to 8.4 × 1013 Hz (383-429 nm) as the Ag NPs/PZT ratio increased from 0.2 to 0.8. This work provides an effective way to broaden the absorption range and enhance the optical properties of such films.

Intercalation of IR absorber into layered double hydroxides: Preparation, thermal stability and selective IR absorption

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

Zhu, Haifeng; Tang, Pinggui; Feng, Yongjun, E-mail: yjfeng@mail.buct.edu.cn

2012-03-15

Highlights: Black-Right-Pointing-Pointer PMIDA anions were intercalated into Mg{sub 2}Al-NO{sub 3} LDH by anion-exchange method. Black-Right-Pointing-Pointer The prepared material has highly selective IR absorption property in 9-11 {mu}m. Black-Right-Pointing-Pointer The obtained material has practical applications as heat-retaining additive. -- Abstract: N-phosphonomethyl aminodiacetic acid (PMIDA) was intercalated into the interlayer spacing of layered double hydroxides (LDH) by an anion-exchange method. The intercalated LDHs were characterized by various techniques such as powder X-ray diffraction (XRD), FT-IR spectroscopy, elemental analysis and simultaneous thermogravimetric and mass spectrometry (TG-MS) in details. The results show the formation of Mg{sub 2}Al-PMIDA LDH based on the expansion of d-spacingmore » from 0.89 nm to 1.22 nm and the disappearance of the characteristic IR absorption band at 1384 cm{sup -1} for NO{sub 3}{sup -} anions. The incorporation of Mg{sub 2}Al-PMIDA LDH into the low density polyethylene (LDPE) as an additive enhances the selectivity of IR absorption in the main wavelength region 9-11 {mu}m for radiant heat loss at night. Mg{sub 2}Al-PMIDA LDH as a heat-retaining additive has practical application in agricultural plastic films.« less

Quantitative Absorption and Kinetic Studies of Transient Species Using Gas Phase Optical Calorimetry

NASA Astrophysics Data System (ADS)

Melnik, Dmitry G.

2014-06-01

Quantitative measurements of the absorption cross-sections and reaction rates constants of free radicals by spectroscopic means requires the knowledge of the absolute concentration of the target species. We have demonstrated earlier that such information can be retrieved from absorption measurements of the well-known ``reporter" molecule, co-produced in radical synthesis. This method is limited to photochemical protocols allowing for production of ``reporters" stochiometrically with the target species. This limitation can be overcome by use of the optical calorimetry (OC) which measures heat signatures of a photochemical protocol. These heat signatures are directly related to the amount of species produced and the thermochemical data of the reactants and stable products whose accuracy is usually substantially higher than that of the absorption data for prospective ``reporters". The implementation of the OC method presented in this talk is based on the measurements of the frequency shift of the resonances due to the change in the optical density of the reactiove sample within a Fabry-Perot cavity caused by deposition of heat from the absorbed photolysis beam and subsequent chemical reactions. Preliminary results will be presented and future development of this experimental technique will be discussed. D. Melnik, R. Chhantyal-Pun and T. A. Miller, J. Phys. Chem. A, 114, 11583, (2010)

The Influence of Ablation on Radiative Heating for Earth Entry

NASA Technical Reports Server (NTRS)

Johnston, Christopher O.; Gnoffo, Peter A.; Sutton, Kenneth

2008-01-01

Using the coupled ablation and radiation capability recently included in the LAURA flowfield solver, this paper investigates the influence of ablation on the shock-layer radiative heating for Earth entry. The extension of the HARA radiation model, which provides the radiation predictions in LAURA, to treat a gas consisting of the elements C, H, O, and N is discussed. It is shown that the absorption coefficient of air is increased with the introduction of the C and H elements. A simplified shock layer model is studied to show the impact of temperature, as well as the abundance of C and H, on the net absorption or emission from an ablation contaminated boundary layer. It is found that the ablation species reduce the radiative flux in the vacuum ultraviolet, through increased absorption, for all temperatures. However, in the infrared region of the spectrum, the ablation species increase the radiative flux, through strong emission, for temperatures above 3,000 K. Thus, depending on the temperature and abundance of ablation species, the contaminated boundary layer may either provide a net increase or decrease in the radiative flux reaching the wall. To assess the validity of the coupled ablation and radiation LAURA analysis, a previously analyzed Mars-return case (15.24 km/s), which contains significant ablation and radiation coupling, is studied. Exceptional agreement with previous viscous shock-layer results is obtained. A 40% decrease in the radiative flux is predicted for ablation rates equal to 20% of the free-stream mass flux. The Apollo 4 peak-heating case (10.24 km/s) is also studied. For ablation rates up to 3.4% of the free-stream mass flux, the radiative heating is reduced by up to 19%, while the convective heating is reduced by up to 87%. Good agreement with the Apollo 4 radiometer data is obtained by considering absorption in the radiometer cavity. For both the Mars return and the Apollo 4 cases, coupled radiation alone is found to reduce the radiative heating by 30 60% and the convective heating by less than 5%.

Navy Expeditionary Technology Transition Program (NETTP)

DTIC Science & Technology

2012-03-02

water vapor from feed air using a zeolite membrane •Temperature/Humidity levels can be met in warm, humid climates without reheating •Allows higher...UNCLASSIFIED, Distribution Unlimited Modular Thermal Hub •Small, efficient absorption cooling •Energy source: Combustion, low- grade waste heat, solar... thermal energy •Reversible operation enables space cooling and heating, and water heating •Modular cooling and heating unit •Monolithic packaging offers

On the Heat Transfer through a Solid Slab Heated Uniformly and Continuously on One of Its Surfaces

ERIC Educational Resources Information Center

Marin, E.; Lara-Bernal, A.; Calderon, A.; Delgado-Vasallo, O.

2011-01-01

Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…

High Speed Blood and Transfusion Equipment

DTIC Science & Technology

2013-10-14

absorption process is entirely reversible. By heating the absorber the ammonia refrigerant is removed from the salt in the vapor phase . The...ligand quantity decreased, the heating capacity would also consistently diminish. However, with the monovariant attribute a single pulse of the...limit, implying perfect heat transfer with no heat losses, can accommodate a volumetric flow rate of blood up to approximately 360 cc/min. When operating

Numerical study for heat generation/absorption in flow of nanofluid by a rotating disk

NASA Astrophysics Data System (ADS)

Aziz, Arsalan; Alsaedi, Ahmed; Muhammad, Taseer; Hayat, Tasawar

2018-03-01

Here MHD three-dimensional flow of viscous nanoliquid by a rotating disk with heat generation/absorption and slip effects is addressed. Thermophoresis and random motion features are also incorporated. Velocity, temperature and concentration slip conditions are imposed at boundary. Applied magnetic field is utilized. Low magnetic Reynolds number and boundary layer approximations have been employed in the problem formulation. Suitable transformations lead to strong nonlinear ordinary differential system. The obtained nonlinear system is solved numerically through NDSolve technique. Graphs have been sketched in order to analyze that how the velocity, temperature and concentration fields are affected by various pertinent variables. Moreover the numerical values for rates of heat and mass transfer have been tabulated and discussed.

Axisymmetric flow of Casson fluid by a swirling cylinder

NASA Astrophysics Data System (ADS)

Javed, Muhammad Faisal; Khan, Muhammad Imran; Khan, Niaz Bahadur; Muhammad, Riaz; Rehman, Muftooh Ur; Khan, Sajjad Wali; Khan, Tufail A.

2018-06-01

The present communication aims to investigate the influence of heat generation/absorption on axisymmetric Casson liquid flow over a stretched cylinder. Flow is caused due to torsional motion of cylinder. The governing physical problem is modelled and transferred into set of coupled nonlinear ordinary differential equations. These equations are solved numerically using built-in-Shooting method. Influence of sundry variables on the swirling velocity, temperature, coefficient of skin friction and heat transfer rate are computed and analyzed in a physical manner. Magnitude of axial skin friction is enhances for larger Reynold number and magnetic parameter while local Nusselt number decays with the enhancement of Casson parameter, heat generation/absorption and magnetic parameter. Comparison with already existing results is also given in the limiting case.

Solar powered absorption cycle heat pump using phase change materials for energy storage

NASA Technical Reports Server (NTRS)

Middleton, R. L.

1972-01-01

Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

A New Look at the Structural and Magnetic Properties of Potassium Neptunate K2NpO4 Combining XRD, XANES Spectroscopy, and Low-Temperature Heat Capacity.

PubMed

Smith, Anna L; Colineau, Eric; Griveau, Jean-Christophe; Popa, Karin; Kauric, Guilhem; Martin, Philippe; Scheinost, Andreas C; Cheetham, Anthony K; Konings, Rudy J M

2017-05-15

The physicochemical properties of the potassium neptunate K 2 NpO 4 have been investigated in this work using X-ray diffraction, X-ray absorption near edge structure (XANES) spectroscopy at the Np-L 3 edge, and low-temperature heat capacity measurements. A Rietveld refinement of the crystal structure is reported for the first time. The Np(VI) valence state has been confirmed by the XANES data, and the absorption edge threshold of the XANES spectrum has been correlated to the Mössbauer isomer shift value reported in the literature. The standard entropy and heat capacity of K 2 NpO 4 have been derived at 298.15 K from the low-temperature heat capacity data. The latter suggest the existence of a magnetic ordering transition around 25.9 K, most probably of the ferromagnetic type.

Thermal conductance of interfaces with molecular layers - low temperature transient absorption study on gold nanorods supported on self assembled monolayers

NASA Astrophysics Data System (ADS)

Wang, Wei; Huang, Jingyu; Murphy, Catherine; Cahill, David; University of Illinois At Urbana Champaign, Department of Materials Science; Engineering Team; Department Collaboration

2011-03-01

While heat transfer via phonons across solid-solid boundary has been a core field in condense matter physics for many years, vibrational energy transport across molecular layers has been less well elucidated. We heat rectangular-shaped gold nanocrystals (nanorods) with Ti-sapphire femtosecond pulsed laser at their longitudinal surface plasmon absorption wavelength to watch how their temperature evolves in picoseconds transient. We observed single exponential decay behavior, which suggests that the heat dissipation is only governed by a single interfacial conductance value. The ``RC'' time constant was 300ps, corresponding to a conductance value of 95MW/ m 2 K. This interfacial conductance value is also a function of ambient temperature since at temperatures as low as 80K, which are below the Debye temperature of organic layers, several phonon modes were quenched, which shut down the dominating channels that conduct heat at room temperature.

Absorptivity Measurements and Heat Source Modeling to Simulate Laser Cladding

NASA Astrophysics Data System (ADS)

Wirth, Florian; Eisenbarth, Daniel; Wegener, Konrad

The laser cladding process gains importance, as it does not only allow the application of surface coatings, but also additive manufacturing of three-dimensional parts. In both cases, process simulation can contribute to process optimization. Heat source modeling is one of the main issues for an accurate model and simulation of the laser cladding process. While the laser beam intensity distribution is readily known, the other two main effects on the process' heat input are non-trivial. Namely the measurement of the absorptivity of the applied materials as well as the powder attenuation. Therefore, calorimetry measurements were carried out. The measurement method and the measurement results for laser cladding of Stellite 6 on structural steel S 235 and for the processing of Inconel 625 are presented both using a CO2 laser as well as a high power diode laser (HPDL). Additionally, a heat source model is deduced.

Chemically reactive species in squeezed flow through modified Fourier's and Fick's laws

NASA Astrophysics Data System (ADS)

Farooq, M.; Ahmad, S.; Javed, M.; Anjum, Aisha

2018-02-01

The squeezing flow of a Newtonian fluid with variable viscosity over a stretchable sheet embedded in Darcy porous medium is addressed. Cattaneo-Christov double diffusion models are adopted to disclose the salient features of heat and mass transport via variable thermal conductivity and variable mass diffusivity instead of conventional Fourier's and Fick's laws. Further, the concept of heat generation/absorption coefficient and first-order chemical reaction are also imposed to illustrate the characteristics of heat and mass transfer. Highly nonlinear computations are developed in dimensionless form and analyzed via the homotopic technique. The variation of flow parameters on velocity, concentration, and temperature distributions are sketched and disclosed physically. The results found that both concentration and temperature distributions decay for higher solutal and thermal relaxation parameters, respectively. Moreover, a higher chemical reaction parameter results in the reduction of the concentration field whereas the temperature profile enhances for a higher heat generation/absorption parameter.

Effect of narrow band nonuniformity on unsteady heat up of water vapor under radiation-conduction combined heat transfer

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

Okamoto, Tatsuyuki; Tanaka, Tomohiro; Morimune, Atsushi

Effect of narrow band nonuniformity on unsteady heat up process of water vapor under radiation-conduction combined heat transfer is examined by comparing the result of numerical simulations with and without incorporation of narrow band nonuniformity. The authors propose a rational and comprehensive computational approach for incorporating the narrow band nonuniformity into numerical simulations of radiative heat transfer when the considered field is nonisothermal. Results of examination exhibited that the contribution of radiative heat transfer to the heat up rate of water vapor may be almost twice overestimated, if the narrow band nonuniformity effect is neglected. Separate analyses of radiative energymore » attributed to wall emission and gas emission clarified that the absorption of wall emission is overestimated and, on the contrary, the absorption of radiation energy emitted by water vapor itself is underestimated if the narrow band nonuniformity is neglected. The reason why such over- or under-estimation is induced is understood by examining the influence of line overlap parameter on the transmittance averaged within a narrow band. Smaller value of line overlap parameter {gamma}/d means more violent narrow band nonuniformity. The broken lines show the narrow band transmittance for flat incident power spectrum, and the solid lines show that for the radiative emission from the absorbing gas itself. It is also clarified that the disregard of the narrow band nonuniformity give rise to serious error in the estimation of absorption rate of wall and gas emission even in the case where the disregard of narrow band nonuniformity bring little change to the temperature distribution. The results illustrated in this paper suggest that the narrow band nonuniformity should not be neglected.« less

Protective Effect of Immunization with Heat-Labile Enterotoxin in Gnotobiotic Rats Monocontaminated with Enterotoxigenic Escherichia coli

PubMed Central

Klipstein, Frederick A.; Engert, Richard F.; Short, Helen B.

1980-01-01

The protective effect of active immunization with a purified preparation of the polymyxin-release form of Escherichia coli heat-labile enterotoxin (LT), administered using a parenteral prime and peroral boosts given after ablation of gastric secretion by means of cimetidine, was assessed in gnotobiotic rats which were challenged by monocontamination with enterotoxigenic strains of E. coli. Water transport was evaluated by the in vivo marker perfusion technique at weekly intervals over a 3-week period after contamination. Water transport in unimmunized control rats was consistently in absorption in those contaminated by a nontoxigenic strain, in secretion during only week 2 in those contaminated by an LT+/− strain, in secretion during weeks 2 and 3 in those contaminated by an LT+/ST+ (heat-stable enterotoxin) strain, and consistently in absorption in those contaminated by an −/ST+ strain. Rats immunized with a booster dosage of 250 μg had a significant increase (P < 0.001) in net water absorption as compared to unimmunized rats, with values in the borderline range of absorption, when challenged with either the LT+/− or LT+/ST+ strains. Rats immunized with a 10-fold-higher boosting dosage had a significant increase (P < 0.001) in net water absorption as compared to those boosted at the lower dosage; water absorption was within the normal range. There was no difference between the ileal bacterial counts of unimmunized and immunized rats challenged by the various strains. These observations indicate that this immunization program provides complete protection in an animal model against challenge by intestinal contamination with enterotoxigenic strains of E. coli which produce LT, either alone or in combination with ST. PMID:6991436

Enhancement of durability properties of heat-treated oil palm shell species lightweight concrete

NASA Astrophysics Data System (ADS)

Yew, Ming Kun; Yew, Ming Chian; Saw, Lip Huat; Ang, Bee Chin; Lee, Min Lee; Lim, Siong Kang; Lim, Jee Hock

2017-04-01

Oil palm shell (OPS) are non-hazardous waste materials and can be used as alternative coarse aggregates to substitute depleting conventional raw materials. A study on preparing the OPS species (dura and tenera) lightweight concrete (LWC) using with and without heat-treated OPS aggregate has been investigated. Two different species of OPS coarse aggregate are subjected to heat treatment at 65 and 130 °C with duration of 1 hour. The results reveal that the slump value of the OPSC increases significantly with an increase in temperature of heat treatment of the tenera OPS aggregates. It is found that the maximum achievable 28-days and 180-days compressive strength is 45.6 and 47.5 MPa, respectively. Furthermore, rapid chloride penetration test (RCPT) and water absorption tests were performance to signify the effects of heat-treated on OPS species LWC. The use of heat-treated OPS LWC induced the advantageous of reducing the permeability and capillary porosity as well as water absorption. Hence, the findings of this study are of primary importance as they revealed the heat treatment on OPS species LWC can be used as a new environmentally friendly method to enhance the durability of OPSLWC.

Decadal evolution of the surface energy budget during the fast warming and global warming hiatus periods in the ERA-interim

NASA Astrophysics Data System (ADS)

Hu, Xiaoming; Sejas, Sergio A.; Cai, Ming; Taylor, Patrick C.; Deng, Yi; Yang, Song

2018-05-01

The global-mean surface temperature has experienced a rapid warming from the 1980s to early-2000s but a muted warming since, referred to as the global warming hiatus in the literature. Decadal changes in deep ocean heat uptake are thought to primarily account for the rapid warming and subsequent slowdown. Here, we examine the role of ocean heat uptake in establishing the fast warming and warming hiatus periods in the ERA-Interim through a decomposition of the global-mean surface energy budget. We find the increase of carbon dioxide alone yields a nearly steady increase of the downward longwave radiation at the surface from the 1980s to the present, but neither accounts for the fast warming nor warming hiatus periods. During the global warming hiatus period, the transfer of latent heat energy from the ocean to atmosphere increases and the total downward radiative energy flux to the surface decreases due to a reduction of solar absorption caused primarily by an increase of clouds. The reduction of radiative energy into the ocean and the surface latent heat flux increase cause the ocean heat uptake to decrease and thus contribute to the slowdown of the global-mean surface warming. Our analysis also finds that in addition to a reduction of deep ocean heat uptake, the fast warming period is also driven by enhanced solar absorption due predominantly to a decrease of clouds and by enhanced longwave absorption mainly attributed to the air temperature feedback.

Comparison of KTP, Thulium, and CO2 laser in stapedotomy using specialized visualization techniques: thermal effects.

PubMed

Kamalski, Digna M A; Verdaasdonk, Rudolf M; de Boorder, Tjeerd; Vincent, Robert; Trabelzini, Franco; Grolman, Wilko

2014-06-01

High-speed thermal imaging enables visualization of heating of the vestibule during laser-assisted stapedotomy, comparing KTP, CO2, and Thulium laser light. Perforation of the stapes footplate with laser bears the risk of heating of the inner ear fluids. The amount of heating depends on absorption of the laser light and subsequent tissue ablation. The ablation of the footplate is driven by strong water absorption for the CO2 and Thulium laser. For the KTP laser wavelength, ablation is driven by carbonization of the footplate and it might penetrate deep into the inner ear without absorption in water. The thermal effects were visualized in an inner ear model, using two new techniques: (1) high-speed Schlieren imaging shows relative dynamic changes of temperatures up to 2 ms resolution in the perilymph. (2) Thermo imaging provides absolute temperature measurements around the footplate up to 40 ms resolution. The high-speed Schlieren imaging showed minimal heating using the KTP laser. Both CO2 and Thulium laser showed heating below the footplate. Thulium laser wavelength generated heating up to 0.6 mm depth. This was confirmed with thermal imaging, showing a rise of temperature of 4.7 (±3.5) °C for KTP and 9.4 (±6.9) for Thulium in the area of 2 mm below the footplate. For stapedotomy, the Thulium and CO2 laser show more extended thermal effects compared to KTP. High-speed Schlieren imaging and thermal imaging are complimentary techniques to study lasers thermal effects in tissue.

Third Order Optical Nonlinearity of Colloidal Metal Nanoclusters Formed by MeV Ion Implantation

NASA Technical Reports Server (NTRS)

Sarkisov, S. S.; Williams, E.; Curley, M.; Ila, D.; Venkateswarlu, P.; Poker, D. B.; Hensley, D. K.

1997-01-01

We report the results of characterization of nonlinear refractive index of the composite material produced by MeV Ag ion implantation of LiNbO(sub 3) crystal (z-cut). The material after implantation exhibited a linear optical absorption spectrum with the surface plasmon peak near 430 nm attributed to the colloidal silver nanoclusters. Heat treatment of the material at 500 deg C caused a shift of the absorption peak to 550 nm. The nonlinear refractive index of the sample after heat treatment was measured in the region of the absorption peak with the Z-scan technique using a tunable picosecond laser source (4.5 ps pulse width).The experimental data were compared against the reference sample made of MeV Cu implanted silica with the absorption peak in the same region. The nonlinear index of the Ag implanted LiNbO(sub 3) sample produced at five times less fluence is on average two times greater than that of the reference.

Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion

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

Thomas, Nathan H.; Chen, Zhen; Fan, Shanhui

Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we then report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In fieldmore » tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. Furthemore, with straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat« less

Determination of absorption coefficient based on laser beam thermal blooming in gas-filled tube.

PubMed

Hafizi, B; Peñano, J; Fischer, R; DiComo, G; Ting, A

2014-08-01

Thermal blooming of a laser beam propagating in a gas-filled tube is investigated both analytically and experimentally. A self-consistent formulation taking into account heating of the gas and the resultant laser beam spreading (including diffraction) is presented. The heat equation is used to determine the temperature variation while the paraxial wave equation is solved in the eikonal approximation to determine the temporal and spatial variation of the Gaussian laser spot radius, Gouy phase (longitudinal phase delay), and wavefront curvature. The analysis is benchmarked against a thermal blooming experiment in the literature using a CO₂ laser beam propagating in a tube filled with air and propane. New experimental results are presented in which a CW fiber laser (1 μm) propagates in a tube filled with nitrogen and water vapor. By matching laboratory and theoretical results, the absorption coefficient of water vapor is found to agree with calculations using MODTRAN (the MODerate-resolution atmospheric TRANsmission molecular absorption database) and HITRAN (the HIgh-resolution atmospheric TRANsmission molecular absorption database).

Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion

DOE PAGES

Thomas, Nathan H.; Chen, Zhen; Fan, Shanhui; ...

2017-07-13

Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we then report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In fieldmore » tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. Furthemore, with straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat« less

Potential Evaluation of Solar Heat Assisted Desiccant Hybrid Air Conditioning System

NASA Astrophysics Data System (ADS)

Tran, Thien Nha; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

The solar thermal driven desiccant dehumidification-absorption cooling hybrid system has superior advantage in hot-humid climate regions. The reasonable air processing of desiccant hybrid air conditioning system and the utility of clean and free energy make the system environment friendly and energy efficient. The study investigates the performance of the desiccant dehumidification air conditioning systems with solar thermal assistant. The investigation is performed for three cases which are combinations of solar thermal and absorption cooling systems with different heat supply temperature levels. Two solar thermal systems are used in the study: the flat plate collector (FPC) and the vacuum tube with compound parabolic concentrator (CPC). The single-effect and high energy efficient double-, triple-effect LiBr-water absorption cooling cycles are considered for cooling systems. COP of desiccant hybrid air conditioning systems are determined. The evaluation of these systems is subsequently performed. The single effect absorption cooling cycle combined with the flat plate collector solar system is found to be the most energy efficient air conditioning system.

Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion.

PubMed

Thomas, Nathan H; Chen, Zhen; Fan, Shanhui; Minnich, Austin J

2017-07-13

Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat.

The Response of the Ocean Thermal Skin Layer to Variations in Incident Infrared Radiation

NASA Astrophysics Data System (ADS)

Wong, Elizabeth W.; Minnett, Peter J.

2018-04-01

Ocean warming trends are observed and coincide with the increase in concentrations of greenhouse gases in the atmosphere resulting from human activities. At the ocean surface, most of the incoming infrared (IR) radiation is absorbed within the top micrometers of the ocean's surface where the thermal skin layer (TSL) exists. Thus, the incident IR radiation does not directly heat the upper few meters of the ocean. This paper investigates the physical mechanism between the absorption of IR radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that given the heat lost through the air-sea interface is controlled by the TSL, the TSL adjusts in response to variations in incident IR radiation to maintain the surface heat loss. This modulates the flow of heat from below and hence controls upper ocean heat content. This hypothesis is tested using the increase in incoming longwave radiation from clouds and analyzing vertical temperature profiles in the TSL retrieved from sea-surface emission spectra. The additional energy from the absorption of increasing IR radiation adjusts the curvature of the TSL such that the upward conduction of heat from the bulk of the ocean into the TSL is reduced. The additional energy absorbed within the TSL supports more of the surface heat loss. Thus, more heat beneath the TSL is retained leading to the observed increase in upper ocean heat content.

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.

CO2 concentration and temperature sensor for combustion gases using diode-laser absorption near 2.7 μm

NASA Astrophysics Data System (ADS)

Farooq, A.; Jeffries, J. B.; Hanson, R. K.

2008-03-01

A new tunable diode-laser sensor based on CO2 absorption near 2.7 μm is developed for high-resolution absorption measurements of CO2 concentration and temperature. The sensor probes the R(28) and P(70) transitions of the ν1+ν3 combination band of CO2 that has stronger absorption line-strengths than the bands near 1.5 μm and 2.0 μm used previously to sense CO2 in combustion gases. The increased absorption strength of transitions in this new wavelength range provides greatly enhanced sensitivity and the potential for accurate measurements in combustion gases with short optical path lengths. Simulated high-temperature spectra are surveyed to find candidate CO2 transitions isolated from water vapor interference. Measurements of line-strength, line position, and collisional broadening parameters are carried out for candidate CO2 transitions in a heated static cell as a function of temperature and compared to literature values. The accuracy of a fixed-wavelength CO2 absorption sensor is determined via measurement of known temperature and CO2 mole fraction in a static cell and shock-tube. Absorption measurements of CO2 are then made in a laboratory flat-flame burner and in ignition experiments of shock-heated n-heptane/O2/argon mixtures to illustrate the potential of this sensor for combustion and reacting-flow applications.

Exploring the Time Evolution of Cool Metallic Absorption Features in UV Burst Spectra

NASA Astrophysics Data System (ADS)

Belmes, K.; Madsen, C. A.; DeLuca, E.

2017-12-01

UV bursts are compact brightenings in active regions that appear in UV images. They are identified through three spectroscopic features: (1) broadening and intensification of NUV/FUV emission lines, (2) the presence of optically thin Si IV emission, and (3) the presence of absorption features from cool metallic ions. Properties (2) and (3) imply that bursts exist at transition region temperatures (≥ 80,000 K) but are located in the cooler lower chromosphere ( 5,000 K). Their energetic and dynamical properties remain poorly constrained. Improving our understanding of this phenomena could help us further constrain the energetic and dynamical properties of the chromosphere, as well as give us insight into whether or not UV bursts contribute to chromospheric and/or coronal heating. We analyzed the time evolution of UV bursts using spectral data from the Interface Region Imaging Spectrograph (IRIS). We inspected Si IV 1393.8 Å line profiles for Ni II 1393.3 Å absorption features to look for signs of heating. Weakening of absorption features over time could indicate heating of the cool ions above the burst, implying that thermal energy from the burst could rapidly conduct upward through the chromosphere. To detect the spectral profiles corresponding to bursts, we applied a four-parameter Gaussian fit to every profile in each observation and took cuts in parameter space to isolate the bursts. We then manually reviewed the remaining profiles by looking for a statistically significant appearance of Ni II 1393.3 Å absorption. We quantified these absorption features by normalizing the Si IV 1393.8 Å emission profiles and measuring the maximum fractional extinction in each. Our preliminary results indicate that Ni II 1393.3 Å absorption may undergo a cycle of strengthening and weakening throughout a burst's lifetime. However, further investigation is needed for confirmation. This work is supported by the NSF-REU solar physics program at SAO, grant number AGS-1560313.

Improved Heat-of-Fusion Energy Storage

NASA Technical Reports Server (NTRS)

Chen, K. H.; Manvi, R.

1982-01-01

Alkali metal/alkali-halide mixtures proposed for preventing solid buildup during energy recovery. When mixture melts (by absorption of heat of fusion), it forms two immiscible liquids. Salt-rich phase is heavier and has higher melting/recrysallization temperature; so during energy recovery salt crystallizes in this phase first. Since heat exchanger for energy recovery is in lighter metal-rich phase, solids do not form and there is no reduction of heat-recovery efficiency.

Radial Distribution of Absorption in a Cesium Heat Pipe with Axial Laser Heating

DTIC Science & Technology

2011-03-01

The spring is used to maintain a clear circular path through the heat pipe and secure the mesh. Two copper crush gaskets attach the Brewster angled ...necessary. The pump beam is assumed to be a Gaussian beam and has been focused through a convex lens to position the beam waist at the center of

Effect of tumor properties on energy absorption, temperature mapping, and thermal dose in 13.56-MHz radiofrequency hyperthermia.

PubMed

Prasad, Bibin; Kim, Subin; Cho, Woong; Kim, Suzy; Kim, Jung Kyung

2018-05-01

Computational techniques can enhance personalized hyperthermia-treatment planning by calculating tissue energy absorption and temperature distribution. This study determined the effect of tumor properties on energy absorption, temperature mapping, and thermal dose distribution in mild radiofrequency hyperthermia using a mouse xenograft model. We used a capacitive-heating radiofrequency hyperthermia system with an operating frequency of 13.56 MHz for in vivo mouse experiments and performed simulations on a computed tomography mouse model. Additionally, we measured the dielectric properties of the tumors and considered temperature dependence for thermal properties, metabolic heat generation, and perfusion. Our results showed that dielectric property variations were more dominant than thermal properties and other parameters, and that the measured dielectric properties provided improved temperature-mapping results relative to the property values taken from previous study. Furthermore, consideration of temperature dependency in the bio heat-transfer model allowed elucidation of precise thermal-dose calculations. These results suggested that this method might contribute to effective thermoradiotherapy planning in clinics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation.

PubMed

Bae, Kyuyoung; Kang, Gumin; Cho, Suehyun K; Park, Wounjhang; Kim, Kyoungsik; Padilla, Willie J

2015-12-14

Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0-200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400-2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5-17 μm. This membrane allows heat localization within the few micrometre-thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20 kW m(-2). This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies.

Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation

PubMed Central

Bae, Kyuyoung; Kang, Gumin; Cho, Suehyun K.; Park, Wounjhang; Kim, Kyoungsik; Padilla, Willie J.

2015-01-01

Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0–200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400–2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5–17 μm. This membrane allows heat localization within the few micrometre-thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20 kW m−2. This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies. PMID:26657535

Heat and Mass Transfer in a Falling Film Evaporator with Aqueous Lithium Bromide Solution

NASA Astrophysics Data System (ADS)

Olbricht, M.; Addy, J.; Luke, A.

2016-09-01

Horizontal tube bundles are often used as falling film evaporators in absorption chillers, especially for systems working at low pressure as H2O/LiBr. Experimental investigations are carried out in a falling film evaporator consisting of a horizontal tube bundle with eighty horizontal tubes installed in an absorption chiller because of a lack of consistent data for heat and mass transfer in the literature. The heat and mass transfer mechanisms and the flow pattern in the falling film are analysed and compared with correlations from literature. The deviations of the experimental data from those of the correlations are within a tolerance of 30%. These deviations may be explained by a change of the flow pattern at a lower Reynolds number than compared to the literature.

Quality assurance: recommended guidelines for safe heating by capacitive-type heating technique to treat patients with metallic implants.

PubMed

Kato, Hirokazu; Kondo, Motoharu; Imada, Hajime; Kuroda, Masahiro; Kamimura, Yoshitsugu; Saito, Kazuyuki; Kuroda, Kagayaki; Ito, Koichi; Takahashi, Hideaki; Matsuki, Hidetoshi

2013-05-01

This article is a redissemination of the previous Japanese Quality Assurance Guide guidelines. Specific absorption rate and temperature distribution were investigated with respect to various aspects including metallic implant size and shape, insertion site, insertion direction, blood flow and heating power, and simulated results were compared with adverse reactions of patients treated by radio frequency capacitive-type heating. Recommended guidelines for safe heating methods for patients with metallic implants are presented based on our findings.

Towards understanding of heat effects in metallic glasses on the basis of macroscopic shear elasticity

PubMed Central

Mitrofanov, Y. P.; Wang, D. P.; Makarov, A. S.; Wang, W. H.; Khonik, V. A.

2016-01-01

It is shown that all heat effects taking place upon annealing of a metallic glass within the glassy and supercooled liquid states, i.e. heat release below the glass transition temperature and heat absorption above it, as well as crystallization-induced heat release, are related to the macroscopic shear elasticity. The underlying physical reason can be understood as relaxation in the system of interstitialcy-type ”defects” (elastic dipoles) frozen-in from the melt upon glass production. PMID:26975587

The development of a solar-powered residential heating and cooling system

NASA Technical Reports Server (NTRS)

1974-01-01

Efforts to demonstrate the engineering feasibility of utilizing solar power for residential heating and cooling are described. These efforts were concentrated on the analysis, design, and test of a full-scale demonstration system which is currently under construction at the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville, Alabama. The basic solar heating and cooling system under development utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating and water heating, and an absorption cycle air conditioner for space cooling.

Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

NASA Astrophysics Data System (ADS)

Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

2009-07-01

Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

Design and Economic Potential of an Integrated High-Temperature Fuel Cell and Absorption Chiller Combined Cooling, Heat, and Power System

NASA Astrophysics Data System (ADS)

Hosford, Kyle S.

Clean distributed generation power plants can provide a much needed balance to our energy infrastructure in the future. A high-temperature fuel cell and an absorption chiller can be integrated to create an ideal combined cooling, heat, and power system that is efficient, quiet, fuel flexible, scalable, and environmentally friendly. With few real-world installations of this type, research remains to identify the best integration and operating strategy and to evaluate the economic viability and market potential of this system. This thesis informs and documents the design of a high-temperature fuel cell and absorption chiller demonstration system at a generic office building on the University of California, Irvine (UCI) campus. This work details the extension of prior theoretical work to a financially-viable power purchase agreement (PPA) with regard to system design, equipment sizing, and operating strategy. This work also addresses the metering and monitoring for the system showcase and research and details the development of a MATLAB code to evaluate the economics associated with different equipment selections, building loads, and economic parameters. The series configuration of a high-temperature fuel cell, heat recovery unit, and absorption chiller with chiller exhaust recirculation was identified as the optimal system design for the installation in terms of efficiency, controls, ducting, and cost. The initial economic results show that high-temperature fuel cell and absorption chiller systems are already economically competitive with utility-purchased generation, and a brief case study of a southern California hospital shows that the systems are scalable and viable for larger stationary power applications.

Layouts of trigeneration plants for centralized power supply

NASA Astrophysics Data System (ADS)

Klimenko, A. V.; Agababov, V. S.; Il'ina, I. P.; Rozhnatovskii, V. D.; Burmakina, A. V.

2016-06-01

One of the possible and, under certain conditions, sufficiently effective methods for reducing consumption of fuel and energy resources is the development of plants for combined generation of different kinds of energy. In the power industry of Russia, the facilities have become widespread in which the cogeneration technology, i.e., simultaneous generation of electric energy and heat, is implemented. Such facilities can use different plants, viz., gas- and steam-turbine plants and gas-reciprocating units. Cogeneration power supply can be further developed by simultaneously supplying the users not only with electricity and heat but also with cold. Such a technology is referred to as trigeneration. To produce electricity and heat, trigeneration plants can use the same facilities that are used in cogeneration, namely, gas-turbine plants, steam-turbine plants, and gas-reciprocating units. Cold can be produced in trigeneration plants using thermotransformers of various kinds, such as vaporcompression thermotransformers, air thermotransformers, and absorption thermotransformers, that operate as chilling machines. The thermotransformers can also be used in the trigeneration plants to generate heat. The main advantage of trigeneration plants based on gas-turbine plants or gas-reciprocating units over cogeneration plants is the increased thermodynamic power supply efficiency owing to utilization of the waste-gas heat not only in winter but also in summer. In the steam-turbine-based trigeneration plants equipped with absorption thermotransformers, the enhancement of the thermodynamic power supply efficiency is determined by the increase in the heat extraction load during the nonheating season. The article presents calculated results that demonstrate higher thermodynamic efficiency of a gas-turbine-based plant with an absorption thermotransformer that operates in the trigeneration mode compared with a cogeneration gas-turbine plant. The structural arrangements of trigeneration plants designed to supply electricity, heat, and cold to the users are shown and the principles of their operation are described. The article presents results of qualitative analysis of different engineering solutions applied to select one combination of power- and heat-generating equipment and thermotransformers or another.

Equator and High-Latitude Ionosphere-to-Magnetosphere Research

DTIC Science & Technology

2010-12-04

characterizing plasma velocity profile in the heated region above HAARP has been clearly established. Specification of D region absorption from Digisonde...Electron density profile, Ground truth, Cal/Val, Doppler skymap, HAARP , Plasma velocity profile, Ionogram autoscaling, D region absorption...2  3  HAARP INVESTIGATIONS ............................................................................ 5  3.1

Alfven wave cyclotron resonance heating

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

White, R.B.; Yosikawa, S.; Oberman, C.

1981-02-01

The resonance absorption of fast Alfven waves at the proton ctclotron resonance of a predominately deuterium plasma is investigated. An approximate dispersion relation is derived, valid in the vicinity of the resonance, which permits an exact calculation of transmission and reflection coefficients. For reasonable plasma parameters significant linear resonance absorption is found.

Improved heat transfer modeling of the eye for electromagnetic wave exposures.

PubMed

Hirata, Akimasa

2007-05-01

This study proposed an improved heat transfer model of the eye for exposure to electromagnetic (EM) waves. Particular attention was paid to the difference from the simplified heat transfer model commonly used in this field. From our computational results, the temperature elevation in the eye calculated with the simplified heat transfer model was largely influenced by the EM absorption outside the eyeball, but not when we used our improved model.

Preparation of Oxidation-Resistant Ultra High Melting Temperature Materials and Structures Using Laser Method

DTIC Science & Technology

2009-06-06

sample within a small ceramic muffle. The microwave absorption coefficient of most ceramics is low, but increases with temperature. Thus, as the...increased using additives with higher absorption 7 coefficients . Silicon carbide has a higher loss tangent at 2.4 GHz than most ceramics, and thus...electron beam sintering. Microwave heating works well for large volumes, but ceramics normally have a low dielectric absorption constant at room

Importance of the green color, absorption gradient, and spectral absorption of chloroplasts for the radiative energy balance of leaves.

PubMed

Kume, Atsushi

2017-05-01

Terrestrial green plants absorb photosynthetically active radiation (PAR; 400-700 nm) but do not absorb photons evenly across the PAR waveband. The spectral absorbance of photosystems and chloroplasts is lowest for green light, which occurs within the highest irradiance waveband of direct solar radiation. We demonstrate a close relationship between this phenomenon and the safe and efficient utilization of direct solar radiation in simple biophysiological models. The effects of spectral absorptance on the photon and irradiance absorption processes are evaluated using the spectra of direct and diffuse solar radiation. The radiation absorption of a leaf arises as a consequence of the absorption of chloroplasts. The photon absorption of chloroplasts is strongly dependent on the distribution of pigment concentrations and their absorbance spectra. While chloroplast movements in response to light are important mechanisms controlling PAR absorption, they are not effective for green light because chloroplasts have the lowest spectral absorptance in the waveband. With the development of palisade tissue, the incident photons per total palisade cell surface area and the absorbed photons per chloroplast decrease. The spectral absorbance of carotenoids is effective in eliminating shortwave PAR (<520 nm), which contains much of the surplus energy that is not used for photosynthesis and is dissipated as heat. The PAR absorptance of a whole leaf shows no substantial difference based on the spectra of direct or diffuse solar radiation. However, most of the near infrared radiation is unabsorbed and heat stress is greatly reduced. The incident solar radiation is too strong to be utilized for photosynthesis under the current CO 2 concentration in the terrestrial environment. Therefore, the photon absorption of a whole leaf is efficiently regulated by photosynthetic pigments with low spectral absorptance in the highest irradiance waveband and through a combination of pigment density distribution and leaf anatomical structures.

Modelling thermal radiation from one-meter diameter methane pool fires

NASA Astrophysics Data System (ADS)

Consalvi, J. L.; Demarco, R.

2012-06-01

The first objective of this article is to implement a comprehensive radiation model in order to predict the radiant fractions and radiative fluxes on remote surfaces in large-scale methane pool fires. The second aim is to quantify the importance of Turbulence-Radiation Interactions (TRIs) in such buoyant flames. The fire-induced flow is modelled by using a buoyancy-modified k-ɛ model and the Steady Laminar Flamelet (SLF) model coupled with a presumed probability density function (pdf) approach. Spectral radiation is modelled by using the Full-Spectrum Correlated-k (FSCK) method. TRIs are taken into account by considering the Optically-Thin Fluctuation Approximation (OTFA). The emission term and the mean absorption coefficient are closed by using a presumed pdf of the mixture fraction, scalar dissipation rate and enthalpy defect. Two 1m-diameter fires with Heat Release Rates (HRR) of 49 kW and 162 kW were simulated. Predicted radiant fractions and radiative heat fluxes are found in reasonable agreement with experimental data. The importance of TRIs is evidenced, computed radiant fractions and radiative heat fluxes being considerably higher than those obtained from calculations based on mean properties. Finally, model results show that the complete absorption coefficient-Planck function correlation should be considered in order to properly take into account the influence of TRIs on the emission term, whereas the absorption coefficient self-correlation in the absorption term reduces significantly the radiant fractions.

Quasi-passive heat sink for high-power laser diodes

NASA Astrophysics Data System (ADS)

Vetrovec, John

2009-02-01

We report on a novel heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink uses a liquid coolant flowing at high speed in a miniature closed and sealed loop. Diode waste heat is received at high flux and transferred to environment, coolant fluid, heat pipe, or structure at a reduced flux. When pumping solid-state or alkali vapor lasers, diode wavelength can be electronically tuned to the absorption features of the laser gain medium. This paper presents the heat sink physics, engineering design, performance modeling, and configurations.

Timonium Elementary School Solar Energy Heating and Cooling Augmentation Experiment. Final Engineering Report. Executive Summary.

ERIC Educational Resources Information Center

AAI Corp., Baltimore, MD.

This report covers a two-year and seven-month solar space heating and cooling experiment conducted at the Timonium Elementary School, Timonium, Maryland. The system was designed to provide a minimum of 50 percent of the energy required during the heating season and to determine the feasibility of using solar energy to power absorption-type…

Analysis and design of an ultrahigh temperature hydrogen-fueled MHD generator

NASA Technical Reports Server (NTRS)

Moder, Jeffrey P.; Myrabo, Leik N.; Kaminski, Deborah A.

1993-01-01

A coupled gas dynamics/radiative heat transfer analysis of partially ionized hydrogen, in local thermodynamic equilibrium, flowing through an ultrahigh temperature (10,000-20,000 K) magnetohydrodynamic (MHD) generator is performed. Gas dynamics are modeled by a set of quasi-one-dimensional, nonlinear differential equations which account for friction, convective and radiative heat transfer, and the interaction between the ionized gas and applied magnetic field. Radiative heat transfer is modeled using nongray, absorbing-emitting 2D and 3D P-1 approximations which permit an arbitrary variation of the spectral absorption coefficient with frequency. Gas dynamics and radiative heat transfer are coupled through the energy equation and through the temperature- and density-dependent absorption coefficient. The resulting nonlinear elliptic problem is solved by iterative methods. Design of such MHD generators as onboard, open-cycle, electric power supplies for a particular advanced airbreathing propulsion concept produced an efficient and compact 128-MWe generator characterized by an extraction ratio of 35.5 percent, a power density of 10,500 MWe/cu m, and a specific (extracted) energy of 324 MJe/kg of hydrogen. The maximum wall heat flux and total wall heat load were 453 MW/sq m and 62 MW, respectively.

A Preliminary Study on Designing and Testing of an Absorption Refrigeration Cycle Powered by Exhaust Gas of Combustion Engine

NASA Astrophysics Data System (ADS)

Napitupulu, F. H.; Daulay, F. A.; Dedy, P. M.; Denis; Jecson

2017-03-01

In order to recover the waste heat from the exhaust gas of a combustion engine, an adsorption refrigeration cycle is proposed. This is a preliminary study on design and testing of a prototype of absorption refrigeration cycle powered by an internal combustion engine. The heat source of the cycle is a compression ignition engine which generates 122.36 W of heat in generator of the cycle. The pairs of absorbent and refrigerant are water and ammonia. Here the generator is made of a shell and tube heat exchanger with number of tube and its length are 20 and 0.69 m, respectively. In the experiments the exhaust gas, with a mass flow rate of 0.00016 kg/s, enters the generator at 110°C and leaves it at 72°C. Here, the solution is heated from 30°C to 90°C. In the evaporator, the lowest temperature can be reached is 17.9°C and COP of the system is 0.45. The main conclusion can be drawn here is that the proposed system can be used to recycle the waste heat and produced cooling. However, the COP is still low.

Spacesuit Evaporator-Absorber-Radiator (SEAR)

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

2011-01-01

For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

System Concept for Remote Measurement of Asteroid Molecular Composition

NASA Astrophysics Data System (ADS)

Hughes, G. B.; Lubin, P. M.; Zhang, Q.; Brashears, T.; Cohen, A. N.; Madajian, J.

2016-12-01

We propose a method for probing the molecular composition of cold solar system targets (asteroids, comets, planets, moons) from a distant vantage, such as from a spacecraft orbiting the object. A directed energy beam is focused on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption of the blackbody radiation occurs within the ejected plume. Bulk composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected material. Our proposed method differs from technologies such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes materials in the target; scattered ions emit characteristic radiation, and the LIBS detector performs atomic composition analysis by observing emission spectra. Standoff distance for LIBS is limited by the strength of characteristic emission, and distances greater than 10 m are problematic. Our proposed method detects atomic and molecular absorption spectra in the plume; standoff distance is limited by the size of heated spot, and the plume opacity; distances on the order of tens of kilometers are immediately feasible. Simulations have been developed for laser heating of a rocky target, with concomitant evaporation. Evaporation rates lead to determination of plume density and opacity. Absorption profiles for selected materials are estimated from plume properties. Initial simulations of absorption profiles with laser heating show great promise for molecular composition analysis from tens of kilometers distance. This paper explores the feasibility a hypothetical mission that seeks to perform surface molecular composition analysis of a near-earth asteroid while the craft orbits the asteroid. Such a system has compelling potential benefit for solar system exploration.

[INVITED] Coherent perfect absorption of electromagnetic wave in subwavelength structures

NASA Astrophysics Data System (ADS)

Yan, Chao; Pu, Mingbo; Luo, Jun; Huang, Yijia; Li, Xiong; Ma, Xiaoliang; Luo, Xiangang

2018-05-01

Electromagnetic (EM) absorption is a common process by which the EM energy is transformed into other kinds of energy in the absorber, for example heat. Perfect absorption of EM with structures at subwavelength scale is important for many practical applications, such as stealth technology, thermal control and sensing. Coherent perfect absorption arises from the interplay of interference and absorption, which can be interpreted as a time-reversed process of lasing or EM emitting. It provides a promising way for complete absorption in both nanophotonics and electromagnetics. In this review, we discuss basic principles and properties of a coherent perfect absorber (CPA). Various subwavelength structures including thin films, metamaterials and waveguide-based structures to realize CPAs are compared. We also discuss the potential applications of CPAs.

Experimental study of refrigeration performance based on linear Fresnel solar thermal photovoltaic system

NASA Astrophysics Data System (ADS)

Song, Jinghui; Yuan, Hui; Xia, Yunfeng; Kan, Weimin; Deng, Xiaowen; Liu, Shi; Liang, Wanlong; Deng, Jianhua

2018-03-01

This paper introduces the working principle and system constitution of the linear Fresnel solar lithium bromide absorption refrigeration cycle, and elaborates several typical structures of absorption refrigeration cycle, including single-effect, two-stage cycle and double-effect lithium bromide absorption refrigeration cycle A 1.n effect absorption chiller system based on the best parameters was introduced and applied to a linear Fresnel solar absorption chiller system. Through the field refrigerator performance test, the results show: Based on this heat cycle design and processing 1.n lithium bromide absorption refrigeration power up to 35.2KW, It can meet the theoretical expectations and has good flexibility and reliability, provides guidance for the use of solar thermal energy.

A Novel Approach to Thermal Design of Solar Modules: Selective-Spectral and Radiative Cooling

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

Sun, Xingshu; Dubey, Rajiv; Chattopadhyay, Shashwata

2016-11-21

For commercial solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 degrees C higher than the ambient. In the long run, extreme self-heating may erode efficiency and shorten lifetime, thereby, dramatically reducing the total energy output by almost ~10% Therefore, it is critically important to develop effective and practical cooling methods to combat PV self-heating. In this paper, we explore two fundamental sources of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical and thermal properties of the solar module to eliminatemore » the parasitic absorption (selective-spectral cooling) and enhance the thermal emission to the cold cosmos (radiative cooling). The proposed technique should cool the module by ~10 degrees C, to be reflected in significant long-term energy gain (~ 3% to 8% over 25 years) for PV systems under different climatic conditions.« less

A new concept for solar pumped lasers

NASA Technical Reports Server (NTRS)

Christiansen, W. H.

1978-01-01

A new approach is proposed in which an intermediate body heated by sunlight is used as the pumping source for IR systems, i.e., concentration solar radiation is absorbed and reradiated via an intermediate blackbody. This body is heated by focused sunlight to a high temperature and its heat losses are engineered to be small. The cooled laser tube (or tubes) is placed within the cavity and is pumped by it. The advantage is that the radiation spectrum is like a blackbody at the intermediate temperature and the laser medium selectively absorbs this light. Focusing requirements, heat losses, and absorption bandwidths of laser media are examined, along with energy balance and potential efficiency. The results indicate that for lasers pumped through an IR absorption spectrum, the use of an intermediate blackbody offers substantial and important advantages. The loss in radiative intensity for optical pumping by a lower-temperature body is partly compensated by the increased solid angle of exposure to the radiative environment.

Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

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

None,

1981-09-01

Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

Influence of radiation absorption by microparticles on the flame velocity and combustion regimes

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

Ivanov, M. F., E-mail: ivanov-mf@mail.ru; Kiverin, A. D.; Liberman, M. A., E-mail: michael.liberman@nordita.org

Thermal radiation from hot combustion products has virtually no effect on the flame propagation in a gas medium. We consider a different situation when even a small concentration of microparticles suspended in a gas absorbs the thermal radiation and heats the gas mixture ahead of the combustion wave front by transferring it to the gas. The mixture heating ahead of the flame front can lead either to a moderate increase in the combustion wave velocity for a fast flame or to its significant increase for a slow flame, depending on the gas mixture reactivity and the normal laminar flame velocity.more » For a slow flame, the heat transfer by radiation from the combustion products can become the dominant mechanism compared to the ordinary molecular thermal conduction that determines the combustion wave structure and velocity. The radiative heating for a spatially nonuniform distribution of particles ahead of the flame front is shown to give rise to a temperature gradient that, in turn, can lead to the ignition of different combustion regimes, depending on the radiation absorption length. In accordance with the Zeldovich gradient mechanism, both deflagration and detonation regimes can be formed in this case. A hydrogen–oxygen flame is used as an example to illustrate the ignition of different combustion wave propagation regimes, depending on the radiation absorption length.« less

In Vivo Evaluation and Proof of Radiofrequency Safety of a Novel Diagnostic MR-Electrophysiology Catheter

PubMed Central

Weiss, Steffen; Wirtz, Daniel; David, Bernd; Krueger, Sascha; Lips, Oliver; Caulfield, Dennis; Pedersen, Steen Fjord; Bostock, Julian; Razavi, Reza; Schaeffter, Tobias

2013-01-01

An MR-electrophysiology (EP) catheter is presented that provides full diagnostic EP functionality and a high level of radiofrequency safety achieved by custom-designed transmission lines. Highly resistive wires transmit intracardiac electrograms and currents for intracardiac pacing. A transformer cable transmits the localization signal of a tip coil. Specific absorption rate simulations and temperature measurements at 1.5 T demonstrate that a wire resistance > 3 kΩ/m limits dielectric heating to a physiologically irrelevant level. Additional wires do not increase tip specific absorption rate significantly, which is important because some clinical catheters require up to 20 electrodes. It is further demonstrated that radiofrequency-induced and pacing-induced resistive heating of the wires is negligible under clinical conditions. The MR-EP catheters provided uncompromised recording of electrograms and cardiac pacing in combination with a standard EP recorder in MR-guided in vivo EP studies, and the tip coil enabled fast and robust catheter localization. In vivo temperature measurements during such a study did not detect any device-related heating, which confirms the high level of safety of the catheter, whereas unacceptable heating was found with a standard EP catheter. The presented concept for the first time enables catheters with full diagnostic EP functionality and active tracking and at the same time a sufficient level of radiofrequency safety for MRI without specific absorption rate-related limitations. PMID:21337409

In vivo evaluation and proof of radiofrequency safety of a novel diagnostic MR-electrophysiology catheter.

PubMed

Weiss, Steffen; Wirtz, Daniel; David, Bernd; Krueger, Sascha; Lips, Oliver; Caulfield, Dennis; Pedersen, Steen Fjord; Bostock, Julian; Razavi, Reza; Schaeffter, Tobias

2011-03-01

An MR-electrophysiology (EP) catheter is presented that provides full diagnostic EP functionality and a high level of radiofrequency safety achieved by custom-designed transmission lines. Highly resistive wires transmit intracardiac electrograms and currents for intracardiac pacing. A transformer cable transmits the localization signal of a tip coil. Specific absorption rate simulations and temperature measurements at 1.5 T demonstrate that a wire resistance > 3 kΩ/m limits dielectric heating to a physiologically irrelevant level. Additional wires do not increase tip specific absorption rate significantly, which is important because some clinical catheters require up to 20 electrodes. It is further demonstrated that radiofrequency-induced and pacing-induced resistive heating of the wires is negligible under clinical conditions. The MR-EP catheters provided uncompromised recording of electrograms and cardiac pacing in combination with a standard EP recorder in MR-guided in vivo EP studies, and the tip coil enabled fast and robust catheter localization. In vivo temperature measurements during such a study did not detect any device-related heating, which confirms the high level of safety of the catheter, whereas unacceptable heating was found with a standard EP catheter. The presented concept for the first time enables catheters with full diagnostic EP functionality and active tracking and at the same time a sufficient level of radiofrequency safety for MRI without specific absorption rate-related limitations. Copyright © 2010 Wiley-Liss, Inc.

Preparation and radar absorptive properties of BaFe12O19 -coated glass fiber

NASA Astrophysics Data System (ADS)

Jia, F.; Xu, M.; Bao, H. Q.; Cui, K.; Zhang, F.

2016-07-01

Traditional passive jamming materials such as chaff and foil showed some limitations in use because they can only reflect the electromagnetic wave. Therefore, to develop a kind of absorptive passive jamming material to make up for deficiencies of traditional passive jamming materials and improve the jamming efficiency is of great significance. In this paper, the BaFe12O19-coated glass fiber, used as a kind of radar absorptive chaff, was prepared by sol-gel dip-coating method. The effects of heat treatment temperature, heat treatment time and coating times on film quality, tensile strength and attenuation efficiency of the samples were discussed. The study shows that an increase of the heat treatment temperature and an extension of the heat treatment time is conducive to the growth of barium ferrite grain, while they would introduce the loss of chaff strength at the same time. In addition, multi-coating process can improve the film quality and attenuation efficiency of the sample. Data show that the 10 times coated samples have a best reflectivity of (15GHz, -6.65dB) and the bandwidth of reflectivity lower than -5dB is11.8 GHz. According to the test results, the prepared material has certain attenuation efficiency in the range of 2GHz-18GHz, having a high practical value.

Engineering Design Handbook Rotational Molding of Plastic Powders

DTIC Science & Technology

1975-04-15

Effect of Relative Humidity on the Moisture Absorption of Ground Celcon M-90 7—3 7—2 Effect of Heating Time on Part Wall Thickness...2.2.1 Drying Cycle Fig. 7-1 shows the effect of relative humidity on moisture absorption of ground resin. These tests were conducted by exposing...312 50% RH O 15 20 DAYS EXPOSURE 25 Reprinted by permission of SPE. Figure 7-1. Effect of Relative Humidity on the Moisture Absorption

Continuum Absorption Coefficient of Atoms and Ions

NASA Technical Reports Server (NTRS)

Armaly, B. F.

1979-01-01

The rate of heat transfer to the heat shield of a Jupiter probe has been estimated to be one order of magnitude higher than any previously experienced in an outer space exploration program. More than one-third of this heat load is due to an emission of continuum radiation from atoms and ions. The existing computer code for calculating the continuum contribution to the total load utilizes a modified version of Biberman's approximate method. The continuum radiation absorption cross sections of a C - H - O - N ablation system were examined in detail. The present computer code was evaluated and updated by being compared with available exact and approximate calculations and correlations of experimental data. A detailed calculation procedure, which can be applied to other atomic species, is presented. The approximate correlations can be made to agree with the available exact and experimental data.

Fabrication, characterization and annealing of polymer-fullerene bulk heterojunction organic solar cells

NASA Astrophysics Data System (ADS)

Sharma, Trupti; Singhal, R.; Vishnoi, R.; Biswas, S. K.

2017-05-01

The structural and optical properties of bulk heterojunction (BHJ) organic solar cell devices have been studied before and after heat treatment. The BHJ structure is fabricated by making the blend of Poly [3-hexylthiophene] (P3HT) and Phenyl C61 butyric acid methyl ester (PCBM) for active layer. After the heat treatment at 140 °C temperature, the device is characterized by X-ray diffraction (XRD) measurement, Raman spectroscopy and UV-visible absorption spectroscopy. The reduced intensity of XRD peak corresponding to (100) plane and decreased crystallite size was observed after annealing. The Raman peak intensity corresponding to C=C stretching mode and optical absorption peak intensity is also found to be reduced after the heat treatment to the device. The diminished intensitiesafter annealing may be due to diffusion of Al into active layer.

Coupled dual loop absorption heat pump

DOEpatents

Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

1985-01-01

A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

Optical absorption of carbon and hydrocarbon species from shock heated acetylene and methane in the 135-220 nm wavelength range

NASA Technical Reports Server (NTRS)

Shinn, J. L.

1981-01-01

Absorption spectroscopy of carbon and hydrocarbon species has been performed in a shock tube at an incident shock condition for a wavelength range of 135-220 nm, in order to obtain information needed for calculating radiation blockage ahead of a planetary probe. Instrumentation consisted of high frequency response pressure transducers, thin-film heat transfer gages, or photomultipliers coupled by light pipes. Two test-gas mixtures, one with acetylene and the other with methane, both diluted with argon, were used to provide a reliable variation of C3 and C2H concentration ratio. Comparison of tests results of the two mixtures, in the temperature range of 3750 + or - 100 K, showed the main absorbing species to be C3. The wavelength for maximum absorption agrees well with the theoretical values of 7.68 eV and 8.03 eV for the vertical excitation energy, and a value of 0.90 for the electronic oscillator strength, obtained from the measured absorption band, is also in good agreement with the predicted value of 0.92.

Temperature dependence of Fe/++/ crystal field spectra - Implications to mineralogical mapping of planetary surfaces

NASA Technical Reports Server (NTRS)

Sung, C.-M.; Singer, R. B.; Parkin, K. M.; Burns, R. G.; Osborne, M.

1977-01-01

Results are reported of Fe(++) crystal field spectral measurements for olivines and pyroxenes up to 400 C. The results are correlated with crystal structure data at elevated temperatures, and the validity of remote-sensed identifications of minerals on hot surfaces of the moon and Mercury is assessed. Two techniques were used to obtain spectra of minerals at elevated temperatures using a spectrophotometer. One employed a diamond cell assembly or a specially designed sample holder to measure polarized absorption spectra of heated single crystals. For the other technique, a sample holder was designed to attach to a diffuse reflectance accessory to produce reflectance spectra of heated powdered samples. Polarized absorption spectra of forsterite at 20-400 C are shown in a graph. Other graphs show the temperature dependence of Fe(++) crystal field bands in olivines, the diffuse reflectance spectra of olivine at 40-400 C, the polarization absorption spectra of orthopyroxene at 30-400 C, the diffuse reflectance spectra of pigeonite at 40-400 C, and unpolarized absorption spectra of lunar pyroxene from Apollo 15 rock 15058.

Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

2016-02-01

A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

Measurements of uranium mass confined in high density plasmas

NASA Technical Reports Server (NTRS)

Stoeffler, R. C.

1976-01-01

An X-ray absorption method for measuring the amount of uranium confined in high density, rf-heated uranium plasmas is described. A comparison of measured absorption of 8 keV X-rays with absorption calculated using Beer Law indicated that the method could be used to measure uranium densities from 3 times 10 to the 16th power atoms/cu cm to 5 times 10 to the 18th power atoms/cu cm. Tests were conducted to measure the density of uranium in an rf-heated argon plasma with UF6 infection and with the power to maintain the discharge supplied by a 1.2 MW rf induction heater facility. The uranium density was measured as the flow rate through the test chamber was varied. A maximum uranium density of 3.85 times 10 to the 17th power atoms/cu cm was measured.

Current fluctuations in quantum absorption refrigerators

NASA Astrophysics Data System (ADS)

Segal, Dvira

2018-05-01

Absorption refrigerators transfer thermal energy from a cold bath to a hot bath without input power by utilizing heat from an additional "work" reservoir. Particularly interesting is a three-level design for a quantum absorption refrigerator, which can be optimized to reach the maximal (Carnot) cooling efficiency. Previous studies of three-level chillers focused on the behavior of the averaged cooling current. Here, we go beyond that and study the full counting statistics of heat exchange in a three-level chiller model. We explain how to obtain the complete cumulant generating function of the refrigerator in a steady state, then derive a partial cumulant generating function, which yields closed-form expressions for both the averaged cooling current and its noise. Our analytical results and simulations are beneficial for the design of nanoscale engines and cooling systems far from equilibrium, with their performance optimized according to different criteria, efficiency, power, fluctuations, and dissipation.

Superior plasmon absorption in iron-doped gold nanoparticles.

PubMed

Amendola, Vincenzo; Saija, Rosalba; Maragò, Onofrio M; Iatì, Maria Antonia

2015-05-21

Although the excitation of localized surface plasmons is associated with enhanced scattering and absorption of incoming photons, only the latter is relevant for the efficient conversion of light into heat. Here we show that the absorption cross section of gold nanoparticles is sensibly increased when iron is included in the lattice as a substitutional dopant, i.e. in a gold-iron nanoalloy. Such an increase is size and shape dependent, with the best performance observed in nanoshells where a 90-190% improvement is found in a size range that is crucial for practical applications. Our findings are unexpected according to the common belief and previous experimental observations that alloys of Au with transition metals show a depressed plasmonic response. These results are promising for the design of efficient plasmonic converters of light into heat and pave the way to more in-depth investigations of the plasmonic properties in noble metal nanoalloys.

Atmospheric solar heating rate in the water vapor bands

NASA Technical Reports Server (NTRS)

Chou, Ming-Dah

1986-01-01

The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

49 CFR 173.225 - Packaging requirements and other provisions for organic peroxides.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Where: q = heat absorption (W) A = wetted area (m2) F = insulation factor (−) (B) Insulation factor (F... insulated vessels F is calculated using the following formula: ER20DE04.003 Where: U = K/L = heat transfer coefficient of the insulation (W·m−2·K−1); where K = heat conductivity of insulation layer (W·m−1·K−1), and L...

Waste-heat-powered icemaker for isolated fishing villages

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

Erickson, D.C.

1995-08-01

A high-lift absorption refrigeration cycle called the ``vapor exchange`` cycle has been applied to the problem of producing refrigeration from low-temperature waste heat. Diesel engine jacket cooling water at 75 C is used as the heat source to produce 10 tons per day of flake ice for a remote community. The icemaker has successfully operated for two fishing seasons at Kotzebue, Alaska.

Effects Of Heat Sinks On VPPA Welds

NASA Technical Reports Server (NTRS)

Nunes, Arthur C.; Steranka, Paul O., Jr.

1991-01-01

Report describes theoretical and experimental study of absorption of heat by metal blocks in contact with metal plate while plate subjected to variable-polarity plasma-arc (VPPA) welding. Purpose of study to contribute to development of comprehensive mathematical model of temperature in weld region. Also relevant to welding of thin sheets of metal to thick blocks of metal, heat treatment of metals, and hotspots in engines.

Evaluation of BW942C, a novel antidiarrheal agent, against enterotoxins of Escherichia coli and Vibrio cholerae.

PubMed Central

Morgan, D R; Sellin, J; Gutierrez, L; DuPont, H L; Wood, L V

1985-01-01

BW942C, an enkephalin-like pentapeptide with anti-diarrheal activity, was tested against crude toxins of Escherichia coli and Vibrio cholerae in the Y-1 adrenal cell assay, rabbit ileal loop assay, and suckling mouse assay. The effects of BW942C on in vitro ion transport were measured in rabbit ileum mounted in Ussing chambers. In vitro, BW942C decreased basal short-circuit current (2.26 and 3.15 mueq cm-2 h-1 in experimental samples and controls, respectively; n = 7, P less than 0.05) and increased basal net Cl absorption (1.59 and 0.50 mueq cm-2 h-1 in experimental samples and controls, respectively; P less than 0.025). Net Na absorption was also increased, but not significantly. BW942C did not block the secretory response to a maximal dose of purified heat-stable toxin. BW942C directly enhanced intestinal fluid absorption. In the Y-1 adrenal cell assay, 5 mg of BW942C per ml inhibited the cytopathic effect caused by cholera toxin or heat-labile enterotoxin of E. coli. In the rabbit ileal loop assay, E. coli heat-stable toxin, E. coli heat-labile enterotoxin, and cholera toxin were inhibited 35 to 70% by administration of BW942C. With the suckling mouse model, the fluid accumulation caused by E. coli heat-stable toxin was ablated by prior treatment with BW942C. The drug is currently being evaluated in patients with acute secretory diarrhea to determine its effect on clinical symptoms. PMID:3838969

Coherent perfect absorption in deeply subwavelength films in the single-photon regime

PubMed Central

Roger, Thomas; Vezzoli, Stefano; Bolduc, Eliot; Valente, Joao; Heitz, Julius J. F.; Jeffers, John; Soci, Cesare; Leach, Jonathan; Couteau, Christophe; Zheludev, Nikolay I.; Faccio, Daniele

2015-01-01

The technologies of heating, photovoltaics, water photocatalysis and artificial photosynthesis depend on the absorption of light and novel approaches such as coherent absorption from a standing wave promise total dissipation of energy. Extending the control of absorption down to very low light levels and eventually to the single-photon regime is of great interest and yet remains largely unexplored. Here we demonstrate the coherent absorption of single photons in a deeply subwavelength 50% absorber. We show that while the absorption of photons from a travelling wave is probabilistic, standing wave absorption can be observed deterministically, with nearly unitary probability of coupling a photon into a mode of the material, for example, a localized plasmon when this is a metamaterial excited at the plasmon resonance. These results bring a better understanding of the coherent absorption process, which is of central importance for light harvesting, detection, sensing and photonic data processing applications. PMID:25991584

40 CFR 63.14 - Incorporations by reference.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Heat of Combustion of Hydrocarbon Fuels by Bomb Calorimeter (High-Precision Method), IBR approved for... for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), IBR... Oxygen Bomb Combustion/Atomic Absorption Method,1 IBR approved for table 6 to subpart DDDDD of this part...

Modeling MHD Stagnation Point Flow of Thixotropic Fluid with Non-uniform Heat Absorption/Generation

NASA Astrophysics Data System (ADS)

Hayat, Tasawar; Shah, Faisal; Khan, Muhammad Ijaz; Alsaedi, Ahmed; Yasmeen, Tabassum

2017-12-01

Here magnetohydrodynamic (MHD) stagnation point flow by nonlinear stretching sheet is discussed. Variable thickness of sheet is accounted. In addition non-uniform heat generation/absorption concept is retained. Numerical treatment to arising nonlinear system is presented. Shooting procedure is adopted for numerical treatment. Graphs and tables lead to physical description of results. It is observed that skin friction enhances for ( H a) and it decays for different rising values of ( K 1), ( K 2) and ( n). Further temperature gradient increases for higher estimation of (Pr) and decreases for larger ( H a). Major findings of present analysis are presented.

Effect of nanosecond UV laser irradiation on luminescence and absorption in silver- and copper-containing phosphate glasses

NASA Astrophysics Data System (ADS)

Murashov, A. A.; Sidorov, A. I.; Stoliarchuk, M. V.

2018-03-01

Experimental evidence is presented that nanosecond UV laser irradiation of silver- and copper-containing barium phosphate glasses leads to luminescence quenching in the visible range. Subsequent heat treatment induces an absorption in the range 350–500 nm. These effects are due to the ionisation and fragmentation of subnanometre molecular clusters by laser radiation and subsequent (heat treatment-induced) formation of nanoparticles possessing plasmon resonance. Our numerical modelling results demonstrate the feasibility of producing stable AgnCum hybrid molecular clusters in glass. Local modification of the optical properties of glass by laser light can be used for optical information recording.

Design and Economic Analysis of a Heating/Absorption Cooling System Operating with Municipal Solid Waste Digester: A Case Study of Gazi University

NASA Astrophysics Data System (ADS)

Coşar, Gökhan; Pooyanfar, Mirparham; Amirabedin, Ehsan; Topal, Hüseyin

2013-12-01

Recovering energy from municipal solid waste (MSW) is one of the most important issues of energy management in developed countries. This raises even more interest as world fossil fuel reserves diminish and fuel prices rise. Being one of main processes of waste disposal, anaerobic digestion can be used as a means to reduce fossil fuel and electricity consumption as well as reducing emissions. With growing demand for cooling in Turkey, especially during warm seasons and considering the energy costs, utilizing heat-driven absorption cooling systems coupled with an anaerobic digester for local cooling purposes is a potentially interesting alternative for electricity driven compression cooling. The aim of this article is to study the viability of utilizing biogas obtained from MSW anaerobic digestion as the main fuel for heating facilities of Gazi University, Turkey and also the energy source for an absorption cooling system designed for the central library of the aforementioned campus. The results prove that the suggested system is sustainably and financially appealing and has the potential to replace the conventional electricity driven cooling systems with a reasonable net present worth; moreover, it can notably reduce carbon dioxide emissions.

Time-resolved X-ray Absorption Spectroscopy for Electron Transport Study in Warm Dense Gold

NASA Astrophysics Data System (ADS)

Lee, Jong-Won; Bae, Leejin; Engelhorn, Kyle; Heimann, Philip; Ping, Yuan; Barbrel, Ben; Fernandez, Amalia; Beckwith, Martha Anne; Cho, Byoung-Ick; GIST Team; IBS Team; LBNL Collaboration; SLAC Collaboration; LLNL Collaboration

2015-11-01

The warm dense Matter represents states of which the temperature is comparable to Fermi energy and ions are strongly coupled. One of the experimental techniques to create such state in the laboratory condition is the isochoric heating of thin metal foil with femtosecond laser pulses. This concept largely relies on the ballistic transport of electrons near the Fermi-level, which were mainly studied for the metals in ambient conditions. However, they were barely investigated in warm dense conditions. We present a time-resolved x-ray absorption spectroscopy measured for the Au/Cu dual layered sample. The front Au layer was isochorically heated with a femtosecond laser pulse, and the x-ray absorption changes around L-edge of Cu, which was attached on the backside of Au, was measured with a picosecond resolution. Time delays between the heating of the `front surface' of Au layer and the alternation of x-ray spectrum of Cu attached on the `rear surface' of Au indicate the energetic electron transport mechanism through Au in the warm dense conditions. IBS (IBS-R012-D1) and the NRF (No. 2013R1A1A1007084) of Korea.

Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

NASA Astrophysics Data System (ADS)

Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

2009-11-01

Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used were Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients revealed a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: (1) shielding of inner monomers after particle consolidation or collapse with water uptake; (2) the lower case contribution of mass transfer through evaporation and condensation at high relative humidity (RH) to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

Hybrid modelling of a high-power X-ray attenuator plasma.

PubMed

Martín Ortega, Álvaro; Lacoste, Ana; Minea, Tiberiu

2018-05-01

X-ray gas attenuators act as stress-free high-pass filters for synchrotron and free-electron laser beamlines to reduce the heat load in downstream optical elements without affecting other properties of the X-ray beam. The absorption of the X-ray beam triggers a cascade of processes that ionize and heat up the gas locally, changing its density and therefore the X-ray absorption. Aiming to understand and predict the behaviour of the gas attenuator in terms of efficiency versus gas pressure, a hybrid model has been developed, combining three approaches: an analytical description of the X-ray absorption; Monte Carlo for the electron thermalization; and a fluid treatment for the electron diffusion, recombination and excited-states relaxation. The model was applied to an argon-filled attenuator prototype built and tested at the European Synchrotron Radiation Facility, at a pressure of 200 mbar and assuming stationary conditions. The results of the model showed that the electron population thermalizes within a few nanoseconds after the X-ray pulse arrival and it occurs just around the X-ray beam path, recombining in the bulk of the gas rather than diffusing to the attenuator walls. The gas temperature along the beam path reached 850 K for 770 W of incident power and 182 W m -1 of absorbed power. Around 70% of the absorbed power is released as visible and UV radiation rather than as heat to the gas. Comparison of the power absorption with the experiment showed an overall agreement both with the plasma radial profile and power absorption trend, the latter within an error smaller than 20%. This model can be used for the design and operation of synchrotron gas attenuators and as a base for a time-dependent model for free-electron laser attenuators.

Waste heat recovery options in a large gas-turbine combined power plant

NASA Astrophysics Data System (ADS)

Upathumchard, Ularee

This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste heat sources are combustion turbine (CT) room ventilation air and lubrication oil return from the power plant. The following options are being considered in this research: absorption chillers for cooling with working fluids Ammonia-Water and Water-Lithium Bromide (in comparison) and Organic Rankine Cycle (ORC) with working fluids R134a and R245fa. The absorption cycles are modeled in three different stages; single-effect, double-effect and half-effect. ORC models used are simple ORC as a baseline, ORC with internal regenerator, ORC two-phase flash expansion ORC and ORC with multiple heat sources. Thermodynamic models are generated and each system is simulated using Engineering Equation Solver (EES) to define the most suitable waste heat recovery options for the power plant. The result will be synthesized and evaluated with respect to exergy utilization efficiency referred as the Second Law effectiveness and net output capacity. Results of the models give recommendation to install a baseline ORC of R134a and a double-effect water-lithium bromide absorption chiller, driven by ventilation air from combustion turbine compartment. The two technologies yield reasonable economic payback periods of 4.6 years and 0.7 years, respectively. The fact that this selected power plant is in its early stage of operation allows both models to economically and effectively perform waste heat recovery during the power plant's life span. Furthermore, the recommendation from this research will be submitted to the Electricity Generating Authority of Thailand (EGAT) for implementation. This study will also be used as an example for other power plants in Thailand to consider waste energy utilization to improve plant efficiency and sustain fuel resources in the future.

Photoluminescence of transparent glass-ceramics based on ZnO nanocrystals and co-doped with Eu3+, Yb3+ ions

NASA Astrophysics Data System (ADS)

Arzumanyan, Grigory M.; Kuznetsov, Evgeny A.; Zhilin, Aleksandr A.; Dymshits, Olga S.; Shemchuk, Daria V.; Alekseeva, Irina P.; Mudryi, Alexandr V.; Zhivulko, Vadim D.; Borodavchenko, Olga M.

2016-12-01

Glasses of the K2Osbnd ZnOsbnd Al2O3sbnd SiO2 system co-doped with Eu2O3 and Yb2O3 were prepared by the melt-quenching technique. Transparent zincite (ZnO) glass-ceramics were obtained by secondary heat-treatments at 680-860 °C. At 860 °C, traces of Eu oxyapatite appeared in addition to ZnO nanocrystals. The average crystal size obtained from the X-ray diffraction data was found to range between 14 and 35 nm. Absorption spectra of the initial glasses are composed of an absorption edge and absorption bands due to electronic transitions of Eu3+ ions. With heat-treatment, the absorption edge pronouncedly shifts to the visible spectral range. The luminescence properties of the glass and glass-ceramics were studied by measuring their excitation and emission spectra at 300, 78, and 4.2 K. Strong red emission of Eu3+ ions dominated by the 5D0-7F2 (612 nm) electric dipole transition was detected. Changes in the luminescence properties of the Eu3+-related excitation and emission bands were observed after heat-treatments at 680 °C and 860 °C. The ZnO nanocrystals showed both broad luminescence (400-850 nm) and free-exciton emission near 3.3 eV at room temperature. The upconversion luminescence spectrum of the initial glass was obtained under excitation of the 976 nm laser source.

Absorption sensor for CO in combustion gases using 2.3 µm tunable diode lasers

NASA Astrophysics Data System (ADS)

Chao, X.; Jeffries, J. B.; Hanson, R. K.

2009-11-01

Tunable diode laser absorption spectroscopy of CO was studied in the controlled laboratory environments of a heated cell and a combustion exhaust rig. Two absorption lines, R(10) and R(11) in the first overtone band of CO near 2.3 µm, were selected from a HITRAN simulation to minimize interference from water vapor at a representative combustion exhaust temperature (~1200 K). The linestrengths and collision broadening coefficients for these lines were measured in a heated static cell. This database was then used in a comparative study of direct absorption and wavelength-modulation absorption. CO concentration measurements using scanned-wavelength direct absorption (DA) and wavelength modulation with the second-harmonic signal normalized by the first-harmonic signal (WMS-2f/1f) all agreed with those measured by a conventional gas sampling analyzer over the range from <10 ppm to 2.3%. As expected, water vapor was found to be the dominant source of background interference for CO detection in combustion flows at high temperatures. Water absorption was measured to a high spectral resolution within the wavelength region 4295-4301 cm-1 at 1100 K, and shown to produce <10 ppm level interference for CO detection in combustion exhausts at temperatures up to 1200 K. We found that the WMS-2f/1f strategy avoids the need for WMS calibration measurements but requires characterization of the wavelength and injection-current intensity modulation of the specific diode laser. We conclude that WMS-2f/1f using the selected R(10) or R(11) transitions in the CO overtone band holds good promise for sensitive in situ detection of ppm-level CO in combustion flows, with high resistance to interference absorption from H2O.

Flexible composite material with phase change thermal storage

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2001-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Flexible composite material with phase change thermal storage

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

1999-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

High Temperature Microwave Dielectric Properties of JSC-1AC Lunar Simulant

NASA Technical Reports Server (NTRS)

Allan, Shawn M.; Merritt, Brandon J.; Griffin, Brittany F.; Hintze, Paul E.; Shulman, Holly S.

2011-01-01

Microwave heating has many potential lunar applications including sintering regolith for lunar surface stabilization and heating regolith for various oxygen production reactors. The microwave properties of lunar simulants must be understood so this technology can be applied to lunar operations. Dielectric properties at microwave frequencies for a common lunar simulant, JSC-1AC, were measured up to 1100 C, which is approximately the melting point. The experimentally determined dielectric properties included real and imaginary permittivity (epsilon', epsilon"), loss tangent (tan delta), and half-power depth, the di stance at which a material absorbs 50% of incident microwave energy. Measurements at 2.45 GHz revealed tan delta of JSC-1A increases from 0.02 at 25 C to 0.31 at 110 C. The corresponding half-power depth decreases from a peak of 286 mm at 110 C, to 13 mm at 1100 C. These data indicate that JSC-1AC becomes more absorbing, and thus a better microwave heater as temperature increases. A half-power depth maximum at 100-200 C presents a barrier to direct microwave heating at low temperatures. Microwave heating experiments confirm the sluggish heating effect of weak absorption below 200 C, and increasingly strong absorption above 200 C, leading to rapid heating and melting of JSC-1AC.

Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

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

Lee, Jin-Yi; Moon, Yong-Jae; Kim, Kap-Sung

2017-07-20

We investigate the heating of an erupting prominence and loops associated with a coronal mass ejection and X-class flare. The prominence is seen as absorption in EUV at the beginning of its eruption. Later, the prominence changes to emission, which indicates heating of the erupting plasma. We find the densities of the erupting prominence using the absorption properties of hydrogen and helium in different passbands. We estimate the temperatures and densities of the erupting prominence and loops seen as emission features using the differential emission measure method, which uses both EUV and X-ray observations from the Atmospheric Imaging Assembly onmore » board the Solar Dynamics Observatory and the X-ray Telescope on board Hinode . We consider synthetic spectra using both photospheric and coronal abundances in these calculations. We verify the methods for the estimation of temperatures and densities for the erupting plasmas. Then, we estimate the thermal, kinetic, radiative loss, thermal conduction, and heating energies of the erupting prominence and loops. We find that the heating of the erupting prominence and loop occurs strongly at early times in the eruption. This event shows a writhing motion of the erupting prominence, which may indicate a hot flux rope heated by thermal energy release during magnetic reconnection.« less

Improvements to water vapor transmission and capillary absorption measurements in porous materials

Treesearch

Samuel L. Zelinka; Samuel V. Glass; Charles R. Boardman

2016-01-01

The vapor permeability (or equivalently the vapor diffusion resistance factor) and the capillary absorption coefficient are frequently used as inputs to hygrothermal or heat, air, and moisture (HAM) models. However, it has been well documented that the methods used to determine these properties are sensitive to the operator, and wide variations in the properties have...

Complete ? -decay pattern for the high-priority decay-heat isotopes I 137 and Xe 137 determined using total absorption spectroscopy

DOE PAGES

Rasco, B. C.; Rykaczewski, K. P.; Fijalkowska, A.; ...

2017-05-31

We measured the complete -decay intensities of 137I and 137Xe with the Modular Total Absorption Spectrometer at Oak Ridge National Laboratory. We describe a novel technique for measuring the -delayed neutron energy spectrum, which also provides a measurement of the -neutron branching ratio, P n.

Low-Cost Gas Heat Pump for Building Space Heating

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

Garrabrant, Michael; Keinath, Christopher

2016-10-11

Gas-fired residential space heating in the U.S is predominantly supplied by furnaces and boilers. These technologies have been approaching their thermodynamic limit over the past 30 years and improvements for high efficiency units have approached a point of diminishing return. Electric heat pumps are growing in popularity but their heating performance at low ambient temperatures is poor. The development of a low-cost gas absorption heat pump would offer a significant improvement to current furnaces and boilers, and in heating dominated climate zones when compared to electric heat pumps. Gas absorption heat pumps (GAHP) exceed the traditional limit of thermal efficiencymore » encountered by typical furnaces and boilers, and maintain high levels of performance at low ambient temperatures. The project team designed and demonstrated two low-cost packaged prototype GAHP space heating systems during the course of this investigation. Led by Stone Mountain Technologies Inc. (SMTI), with support from A.O. Smith, and the Gas Technology Institute (GTI), the cross-functional team completed research and development tasks including cycle modeling, 8× scaling of a compact solution pump, combustion system development, breadboard evaluation, fabrication of two packaged prototype units, third party testing of the first prototype, and the evaluation of cost and energy savings compared to high and minimum efficiency gas options. Over the course of the project and with the fabrication of two Alpha prototypes it was shown that this technology met or exceeded most of the stated project targets. At ambient temperatures of 47, 35, 17 and -13°F the prototypes achieved gas based coefficients of performance of 1.50, 1.44, 1.37, and 1.17, respectively. Both units operated with parasitic loads well below the 750 watt target with the second Alpha prototype operating 75-100 watts below the first Alpha prototype. Modulation of the units at 4:1 was achieved with the project goal of 2:1 modulation, which will allow for improved load matching. In addition, the energy savings analysis showed that a house in Albany, NY, Chicago, IL and Minneapolis, MN would save roughly 32, 28.5 and 36.5 MBtu annually when compared to a 100% efficient boiler, respectively. The gas absorption heat pump achieves this performance by using high grade heat from the combustion of natural gas in combination with low grade heat extracted from the ambient to produce medium grade heat suitable for space and water heating. Expected product features include conventional outdoor installation practices, 4:1 modulation, and reasonable economic payback. These factors position the technology to gain significant market penetration, resulting in a large reduction of energy use and greenhouse gas emissions for residential space heating.« less

Microwave Induced Direct Bonding of Single Crystal Silicon Wafers

NASA Technical Reports Server (NTRS)

Budraa, N. K.; Jackson, H. W.; Barmatz, M.

1999-01-01

We have heated polished doped single-crystal silicon wafers in a single mode microwave cavity to temperatures where surface to surface bonding occurred. The absorption of microwaves and heating of the wafers is attributed to the inclusion of n-type or p-type impurities into these substrates. A cylindrical cavity TM (sub 010) standing wave mode was used to irradiate samples of various geometry's at positions of high magnetic field. This process was conducted in vacuum to exclude plasma effects. This initial study suggests that the inclusion of impurities in single crystal silicon significantly improved its microwave absorption (loss factor) to a point where heating silicon wafers directly can be accomplished in minimal time. Bonding of these substrates, however, occurs only at points of intimate surface to surface contact. The inclusion of a thin metallic layer on the surfaces enhances the bonding process.

Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy

PubMed Central

Wróbel, Maciej S.; Jędrzejewska-Szczerska, Malgorzata; Galla, Stanislaw; Piechowski, Leszek; Sawczak, Miroslaw; Popov, Alexey P.; Bykov, Alexander V.; Tuchin, Valery V.; Cenian, Adam

2015-01-01

Abstract. Skin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to thermal conductivity and capacitance); thus, they can be used as substitutes for human skin for approximate evaluation of laser heating efficiency in an almost real environment. Thermographic imaging was applied to measure the spatial and temporal temperature distributions on the surface of laser-irradiated phantoms. The study yielded results of heating with regard to phantom thickness and absorption, as well as laser settings. The methodology developed can be used in practice for preclinical evaluations of laser treatment for dermatology. PMID:26263414

The effect of velocity slip and multiple convective boundary conditions in a Darcian porous media with microorganism past a vertical stretching/shrinking sheet

NASA Astrophysics Data System (ADS)

Latiff, Nur Amalina Abdul; Yahya, Elisa; Ismail, Ahmad Izani Md.; Amirsom, Ardiana; Basir, Faisal

2017-08-01

An analysis is carried out to study the steady mixed convective boundary layer flow of a nanofluid in a Darcian porous media with microorganisms past a vertical stretching/shrinking sheet. Heat generation/absorption and chemical reaction effects are incorporated in the model. The partial differential equations are transformed into a system of ordinary differential equations by using similarity transformations generated by scaling group transformations. The transformed equations with boundary conditions are solved numerically. The effects of controlling parameters such as velocity slip, Darcy number, heat generation/absorption and chemical reaction on the skin friction factor, heat transfer, mass transfer and microorganism transfer are shown and discuss through graphs. Comparison of numerical solutions in the present study with the previous existing results in literature are made and comparison results are in very good agreement.

Magnetic nanoparticles for enhancing the effectiveness of ultrasonic hyperthermia

NASA Astrophysics Data System (ADS)

Józefczak, A.; Kaczmarek, K.; Hornowski, T.; Kubovčíková, M.; Rozynek, Z.; Timko, M.; Skumiel, A.

2016-06-01

Ultrasonic hyperthermia is a method of cancer treatment in which tumors are exposed to an elevated cytotoxic temperature using ultrasound (US). In conventional ultrasonic hyperthermia, the ultrasound-induced heating in the tumor is achieved through the absorption of wave energy. However, to obtain appropriate temperature in reasonable time, high US intensities, which can have a negative impact on healthy tissues, are required. The effectiveness of US for medical purposes can be significantly improved by using the so-called sonosensitizers, which can enhance the thermal effect of US on the tissue by increasing US absorption. One possible candidate for such sonosensitizers is magnetic nanoparticles with mean sizes of 10-300 nm, which can be efficiently heated because of additional attenuation and scattering of US. Additionally, magnetic nanoparticles are able to produce heat in the alternating magnetic field (magnetic hyperthermia). The synergetic application of ultrasonic and magnetic hyperthermia can lead to a promising treatment modality.

Ionic Liquids for Utilization of Waste Heat from Distributed Power Generation Systems

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

Joan F. Brennecke; Mihir Sen; Edward J. Maginn

2009-01-11

The objective of this research project was the development of ionic liquids to capture and utilize waste heat from distributed power generation systems. Ionic Liquids (ILs) are organic salts that are liquid at room temperature and they have the potential to make fundamental and far-reaching changes in the way we use energy. In particular, the focus of this project was fundamental research on the potential use of IL/CO2 mixtures in absorption-refrigeration systems. Such systems can provide cooling by utilizing waste heat from various sources, including distributed power generation. The basic objectives of the research were to design and synthesize ILsmore » appropriate for the task, to measure and model thermophysical properties and phase behavior of ILs and IL/CO2 mixtures, and to model the performance of IL/CO2 absorption-refrigeration systems.« less

Numerical simulation of ultrasound-thermotherapy combining nonlinear wave propagation with broadband soft-tissue absorption.

PubMed

Ginter, S

2000-07-01

Ultrasound (US) thermotherapy is used to treat tumours, located deep in human tissue, by heat. It features by the application of high intensity focused ultrasound (HIFU), high local temperatures of about 90 degrees C and short treating time of a few seconds. Dosage of the therapy remains a problem. To get it under control, one has to know the heat source, i.e. the amount of absorbed US power, which shows nonlinear influences. Therefore, accurate simulations are essential. In this paper, an improved simulation model is introduced which enables accurate investigations of US thermotherapy. It combines nonlinear US propagation effects, which lead to generation of higher harmonics, with a broadband frequency-power law absorption typical for soft tissue. Only the combination of both provides a reliable calculation of the generated heat. Simulations show the influence of nonlinearities and broadband damping for different source signals on the absorbed US power density distribution.

Climate Sensitivity to Realistic Solar Heating of Snow and Ice

NASA Astrophysics Data System (ADS)

Flanner, M.; Zender, C. S.

2004-12-01

Snow and ice-covered surfaces are highly reflective and play an integral role in the planetary radiation budget. However, GCMs typically prescribe snow reflection and absorption based on minimal knowledge of snow physical characteristics. We performed climate sensitivity simulations with the NCAR CCSM including a new physically-based multi-layer snow radiative transfer model. The model predicts the effects of vertically resolved heating, absorbing aerosol, and snowpack transparency on snowpack evolution and climate. These processes significantly reduce the model's near-infrared albedo bias over deep snowpacks. While the current CCSM implementation prescribes all solar radiative absorption to occur in the top 2 cm of snow, we estimate that about 65% occurs beneath this level. Accounting for the vertical distribution of snowpack heating and more realistic reflectance significantly alters snowpack depth, surface albedo, and surface air temperature over Northern Hemisphere regions. Implications for the strength of the ice-albedo feedback will be discussed.

Heating and cooling of the earth's plasma sheet

NASA Technical Reports Server (NTRS)

Goertz, C. K.

1990-01-01

Magnetic-field models based on pressure equilibrium in the quiet magnetotail require nonadiabatic cooling of the plasma as it convects inward or a decrease of the flux tube content. Recent in situ observations of plasma density and temperature indicate that, during quiet convection, the flux tube content may actually increase. Thus the plasma must be cooled during quiet times. The earth plasma sheet is generally significantly hotter after the expansion phase of a substorm than before the plasma sheet thinning begins and cools during the recovery phase. Heating mechanisms such as reconnection, current sheet acceleration, plasma expansion, and resonant absorption of surface waves are discussed. It seems that all mechanisms are active, albeit in different regions of the plasma sheet. Near-earth tail signatures of substorms require local heating as well as a decrease of the flux tube content. It is shown that the resonant absorption of surface waves can provide both.

Observation of Electron Bernstein Wave Heating in the MST Reversed Field Pinch

NASA Astrophysics Data System (ADS)

Seltzman, Andrew; Anderson, Jay; Dubois, Ami; Almagri, Abdulgader; Nonn, Paul; McCollam, Karsten; Chapman, Brett; Goetz, John; Forest, Cary

2016-10-01

We report the first observation of electron Bernstein wave heating in the MST RFP. Similar to a high density stellarator, the RFP is inaccessible to electromagnetic ECRH. The plasma current and |B|operating range of MST allows a 5.5 GHz RF source (100kW, 4ms pulse) to heat on the fundamental and up to 4th harmonic EC resonances. With an x-ray diagnostic most sensitive to edge electrons located +12 degrees toroidally from the antenna, the measured emission is a strong function of predicted heating inside versus outside the Bt =0 reversal layer of the RFP. Measured during a scan of plasma current, distinct edges in a plot of emissivity versus predicted deposition layer align with the deposition layers crossing of this reversal layer and confirm EBW heating on the fundamental through 4th EC harmonic. Additional confirmation of the absorption location has been demonstrated by using auxiliary poloidal current drive to reduce electron diffusion rates and sweep the location of the Bt =0 surface across a static RF absorption location in RFP discharges. In these discharges EBW enhancement of the 15-40keV x-ray energies has been observed. Work supported by USDOE.

Chemical heat pump

DOEpatents

Greiner, Leonard

1980-01-01

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer. The heat pump part of the system heats or cools a house or other structure through a combination of evaporation and absorption or, conversely, condensation and desorption, in a pair of containers. A set of automatic controls change the system for operation during winter and summer months and for daytime and nighttime operation to satisfactorily heat and cool a house during an entire year. The absorber chamber is subjected to solar heating during regeneration cycles and is covered by one or more layers of glass or other transparent material. Daytime home air used for heating the home is passed at appropriate flow rates between the absorber container and the first transparent cover layer in heat transfer relationship in a manner that greatly reduce eddies and resultant heat loss from the absorbant surface to ambient atmosphere.

Operation of a cascade air conditioning system with two-phase loop

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

Feng, Yinshan; Wang, Jinliang; Zhao, Futao

A method of operating a heat transfer system includes starting operation of a first heat transfer fluid vapor/compression circulation loop including a fluid pumping mechanism, a heat exchanger for rejecting thermal energy from a first heat transfer fluid, and a heat absorption side of an internal heat exchanger. A first conduit in a closed fluid circulation loop circulates the first heat transfer fluid therethrough. Operation of a second two-phase heat transfer fluid circulation loop is started after starting operation of the first heat transfer fluid circulation loop. The second heat transfer fluid circulation loop transfers heat to the first heatmore » transfer fluid circulation loop through the internal heat exchanger and includes a heat rejection side of the internal heat exchanger, a liquid pump, and a heat exchanger evaporator. A second conduit in a closed fluid circulation loop circulates a second heat transfer fluid therethrough.« less

Electromagnetic scattering and absorption by thin walled dielectric cylinders with application to ice crystals

NASA Technical Reports Server (NTRS)

Senior, T. B. A.; Weil, H.

1977-01-01

Important in the atmospheric heat balance are the reflection, transmission, and absorption of visible and infrared radiation by clouds and polluted atmospheres. Integral equations are derived to evaluate the scattering and absorption of electromagnetic radiation from thin cylindrical dielectric shells of arbitrary cross section when irradiated by a plane wave of any polarization incident in a plane perpendicular to the generators. Application of the method to infinitely long hexagonal cylinders has yielded numerical scattering and absorption data which simulate columnar sheath ice crystals. It is found that the numerical procedures are economical for cylinders having perimeters less than approximately fifteen free-space wavelengths.

Absorption/transmission measurements of PSAP particle-laden filters from the Biomass Burning Observation Project (BBOP) field campaign

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

Presser, Cary; Nazarian, Ashot; Conny, Joseph M.

Absorptivity measurements with a laser-heating approach, referred to as the laser-driven thermal reactor (LDTR), were carried out in the infrared and applied at ambient (laboratory) nonreacting conditions to particle-laden filters from a three-wavelength (visible) particle/soot absorption photometer (PSAP). Here, the particles were obtained during the Biomass Burning Observation Project (BBOP) field campaign. The focus of this study was to determine the particle absorption coefficient from field-campaign filter samples using the LDTR approach, and compare results with other commercially available instrumentation (in this case with the PSAP, which has been compared with numerous other optical techniques).

Absorption/transmission measurements of PSAP particle-laden filters from the Biomass Burning Observation Project (BBOP) field campaign

DOE PAGES

Presser, Cary; Nazarian, Ashot; Conny, Joseph M.; ...

2016-12-02

Absorptivity measurements with a laser-heating approach, referred to as the laser-driven thermal reactor (LDTR), were carried out in the infrared and applied at ambient (laboratory) nonreacting conditions to particle-laden filters from a three-wavelength (visible) particle/soot absorption photometer (PSAP). Here, the particles were obtained during the Biomass Burning Observation Project (BBOP) field campaign. The focus of this study was to determine the particle absorption coefficient from field-campaign filter samples using the LDTR approach, and compare results with other commercially available instrumentation (in this case with the PSAP, which has been compared with numerous other optical techniques).

Calculation tool for transported geothermal energy using two-step absorption process

DOE Data Explorer

Kyle Gluesenkamp

2016-02-01

This spreadsheet allows the user to calculate parameters relevant to techno-economic performance of a two-step absorption process to transport low temperature geothermal heat some distance (1-20 miles) for use in building air conditioning. The parameters included are (1) energy density of aqueous LiBr and LiCl solutions, (2) transportation cost of trucking solution, and (3) equipment cost for the required chillers and cooling towers in the two-step absorption approach. More information is available in the included public report: "A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings"

Absorption heat pump for space applications

NASA Technical Reports Server (NTRS)

Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

1993-01-01

In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

Researching of the possibility of using absorption heat exchangers for creating the low return temperature heat supply systems based on CHP generation

NASA Astrophysics Data System (ADS)

Yavorovsky, Y. V.; Malenkov, A. S.; Zhigulina, Y. V.; Romanov, D. O.; Kurzanov, S. Y.

2017-11-01

This paper deals with the variant of modernization of the heat point within urban heat supply network in order to create the system of heat and cold supply on its basis, providing the suppliers with heat in cold months and with heat and cold in warm months. However, in cold months in the course of heating system operation, the reverse delivery water temperature is maintained below 40 °C. The analysis of heat and power indicators of the heat and cold supply system under different operating conditions throughout the year was conducted. The possibility to use the existing heat networks for the cold supply needs was estimated. The advantages of the system over the traditional heat supply systems that use Combined Heat and Power (CHP) plant as a heat source as exemplified by heat supply system from CHP with ST-80 turbine were demonstrated.

Non-Darcy flow of water-based carbon nanotubes with nonlinear radiation and heat generation/absorption

NASA Astrophysics Data System (ADS)

Hayat, T.; Ullah, Siraj; Khan, M. Ijaz; Alsaedi, A.; Zaigham Zia, Q. M.

2018-03-01

Here modeling and computations are presented to introduce the novel concept of Darcy-Forchheimer three-dimensional flow of water-based carbon nanotubes with nonlinear thermal radiation and heat generation/absorption. Bidirectional stretching surface induces the flow. Darcy's law is commonly replace by Forchheimer relation. Xue model is implemented for nonliquid transport mechanism. Nonlinear formulation based upon conservation laws of mass, momentum and energy is first modeled and then solved by optimal homotopy analysis technique. Optimal estimations of auxiliary variables are obtained. Importance of influential variables on the velocity and thermal fields is interpreted graphically. Moreover velocity and temperature gradients are discussed and analyzed. Physical interpretation of influential variables is examined.

Thermodynamic Analysis and Optimization of a High Temperature Triple Absorption Heat Transformer

PubMed Central

Khamooshi, Mehrdad; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana

2014-01-01

First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle. PMID:25136702

Inactivation of Salmonella enterica by UV-C Light Alone and in Combination with Mild Temperatures

PubMed Central

Gayán, E.; Serrano, M. J.; Raso, J.; Álvarez, I.

2012-01-01

The aim of this investigation was to study the efficacy of the combined processes of UV light and mild temperatures for the inactivation of Salmonella enterica subsp. enterica and to explore the mechanism of inactivation. The doses to inactivate the 99.99% (4D) of the initial population ranged from 18.03 (Salmonella enterica serovar Typhimurium STCC 878) to 12.75 J ml−1 (Salmonella enterica serovar Enteritidis ATCC 13076). The pH and water activity of the treatment medium did not change the UV tolerance, but it decreased exponentially by increasing the absorption coefficient. An inactivating synergistic effect was observed by applying simultaneous UV light and heat treatment (UV-H). A less synergistic effect was observed by applying UV light first and heat subsequently. UV did not damage cell envelopes, but the number of injured cells was higher after a UV-H treatment than after heating. The synergistic effect observed by combining simultaneous UV and heat treatment opens the possibility to design combined treatments for pasteurization of liquid food with high UV absorptivity, such as fruit juices. PMID:23001665

Fluid absorption solar energy receiver

NASA Technical Reports Server (NTRS)

Bair, Edward J.

1993-01-01

A conventional solar dynamic system transmits solar energy to the flowing fluid of a thermodynamic cycle through structures which contain the gas and thermal energy storage material. Such a heat transfer mechanism dictates that the structure operate at a higher temperature than the fluid. This investigation reports on a fluid absorption receiver where only a part of the solar energy is transmitted to the structure. The other part is absorbed directly by the fluid. By proportioning these two heat transfer paths the energy to the structure can preheat the fluid, while the energy absorbed directly by the fluid raises the fluid to its final working temperature. The surface temperatures need not exceed the output temperature of the fluid. This makes the output temperature of the gas the maximum temperature in the system. The gas can have local maximum temperatures higher than the output working temperature. However local high temperatures are quickly equilibrated, and since the gas does not emit radiation, local high temperatures do not result in a radiative heat loss. Thermal radiation, thermal conductivity, and heat exchange with the gas all help equilibrate the surface temperature.

Thermal radiation and heat generation/absorption aspects in third grade magneto-nanofluid over a slendering stretching sheet with Newtonian conditions

NASA Astrophysics Data System (ADS)

Qayyum, Sajid; Hayat, Tasawar; Alsaedi, Ahmed

2018-05-01

Mathematical modeling for magnetohydrodynamic (MHD) radiative flow of third grade nano-material bounded by a nonlinear stretching sheet with variable thickness is introduced. The sheet moves with nonlinear velocity. Definitions of thermal radiation and heat generation/absorption are utilized in the energy expression. Intention in present investigation is to develop a model for nanomaterial comprising Brownian motion and thermophoresis phenomena. Newtonian conditions for heat and mass species are imposed. Governing equations of the locally similar flow are attempted through a homotopic technique and behaviors of involved variables on the flow fields are displayed graphically. It is revealed that increasing values of thermal conjugate variable corresponds to high temperature. Numerical investigation are explored to obtain the results of skin friction coefficient and local Nusselt and Sherwood numbers. It is revealed that velocity field reduces in the frame of magnetic variable while reverse situation is observed due to mixed convection parameter. Here qualitative behaviors of thermal field and heat transfer rate are opposite for thermophoresis variable. Moreover nanoparticle concentration and local Sherwood number via Brownian motion parameter are opposite.

Glass heat pipe evacuated tube solar collector

DOEpatents

McConnell, Robert D.; Vansant, James H.

1984-01-01

A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

Damage Caused to Polyurethane Foams by Aging, Simulated Sunlight Exposure, Heat and Fire

DTIC Science & Technology

1984-07-01

vented configuration ............ .................. 11 4 Sample of the tan-colored solid formed upon pyrolysis of blue foam ..... .............. .. 21...54 26 Infrared absorption spectrum of the solid, tan-colored pyrolysis product formed from blue polyurethane foam ..... .............. .. 55 27...Infrared absorption spectrum of the liquid, brown-colored pyrolysis product formed from blue polyurethane foam ..... .............. .. 56 28 Fuel vent

Moving beyond the limits of mass transport in liquid absorbent microfilms through the implementation of surface-induced vortices

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

Bigham, S; Yu, DZ; Chugh, D

2014-02-01

The slow diffusion of an absorbate molecule into an absorbent often makes the absorption process a rate-limiting step in many applications. In cases involving an absorbate with a high heat of phase change, such as water absorption into a LiBr (lithium bromide) solution, the absorption rate is further slowed due to significant heating of the absorbent. Recently, it has been demonstrated that constraining a LiBr solution film by a hydrophobic porous structure enables manipulation of the solution flow thermohydraulic characteristics. Here, it is shown that mass transport mode in a constrained laminar solution flow can be changed from diffusive tomore » advective. This change in mode is accomplished through stretching and folding the laminar streamlines within the solution film via the implementation of micro-scale features on the flow channel surface. The process induces vortices within the solution film, which continuously bring concentrated solution from the bottom and middle of the solution channel to its interface with the vapor phase, thus leading to a significant enhancement in the absorption rate. The detailed physics of the involved transport processes is elucidated using the LBM (Lattice Boltzmann Method). Published by Elsevier Ltd.« less

Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

NASA Astrophysics Data System (ADS)

Agrawal, Tanmay; Varun; Kumar, Anoop

2015-10-01

Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Astrophysics Data System (ADS)

Harber, H.

1981-09-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

Design and operation of a solar heating and cooling system for a residential size building

NASA Technical Reports Server (NTRS)

Littles, J. W.; Humphries, W. R.; Cody, J. C.

1978-01-01

The first year of operation of solar house is discussed. Selected design information, together with a brief system description is included. The house was equipped with an integrated solar heating and cooling system which uses fully automated state-of-the art. Evaluation of the data indicate that the solar house heating and cooling system is capable of supplying nearly 100 percent of the thermal energy required for heating and approximately 50 percent of the thermal energy required to operate the absorption cycle air conditioner.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Technical Reports Server (NTRS)

Harber, H.

1981-01-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

Evaluation and selection of refrigeration systems for lunar surface and space applications

NASA Technical Reports Server (NTRS)

Copeland, R. J.; Blount, T. D.; Williams, J. L.

1971-01-01

Evaluated are the various refrigeration machines which could be used to provide heat rejection in environmental control systems for lunar surface and spacecraft applications, in order to select the best refrigeration machine for satisfying each individual application and the best refrigeration machine for satisfying all of the applications. The refrigeration machine considered include: (1) vapor comparison cycle (work-driven); (2) vapor adsorption cycle (heat-driven); (3) vapor absorption cycle (heat-driven); (4) thermoelectric (electrically-driven); (5) gas cycle (work driven); (6) steam-jet (heat-driven).

Heat storage in alloy transformations

NASA Technical Reports Server (NTRS)

Birchenall, C. E.; Gueceri, S. I.

1980-01-01

The theory of eutectic transformation was examined to find guidelines to the best material combinations to examine. The heats of transformation were measured calorimetrically, and the volume changes of expanding solid mixtures and homogeneous liquid solutions, especially during the transformation between the two states at fixed temperature, were measured by changes in X-ray absorption. Heat flow models appropriate to storage in phase change materials were developed along with efficient calculating procedures so that the relative importance of the problems associated with energy storage density, heat conduction, and similar properties could be assessed.

High-temperature multipass cell for infrared spectroscopy of heated gases and vapors.

PubMed

Bartlome, R; Baer, M; Sigrist, M W

2007-01-01

In absorption spectroscopy, infrared spectra of heated gases or condensed samples in the vapor phase are usually recorded with a single pass heated gas cell. This device exhibits two orders of magnitude lower sensitivity than the high-temperature multipass cell presented in this article. Our device is a novel type of compact long path absorption cell that can withstand aggressive chemicals in addition to temperatures up to 723 K. The construction of the cell and its technical features are described in detail, paying special attention to the mechanisms that compensate for thermal expansion and that allow the user to vary the optical path length under any thermal or vacuum condition. The cell may be used with a laser source or implemented within a Fourier transform infrared spectrometer. Its design is compatible with optical arrangements using astigmatic mirrors or spherical mirrors in a Herriott configuration. Here we implement a homebuilt Herriott-type cell with a total optical path length of up to 35 m. In order to demonstrate the feasibility of the cell, methane and water vapor absorption lines showing dissimilar temperature effects on line intensity were recorded with the help of a mid-infrared laser source tunable between 3 and 4 microm. Emphasis is put on lines that are too weak to be recorded with a single pass cell.

Metasurfaces Leveraging Solar Energy for Icephobicity.

PubMed

Mitridis, Efstratios; Schutzius, Thomas M; Sicher, Alba; Hail, Claudio U; Eghlidi, Hadi; Poulikakos, Dimos

2018-06-29

Inhibiting ice accumulation on surfaces is an energy-intensive task and is of significant importance in nature and technology where it has found applications in windshields, automobiles, aviation, renewable energy generation, and infrastructure. Existing methods rely on on-site electrical heat generation, chemicals, or mechanical removal, with drawbacks ranging from financial costs to disruptive technical interventions and environmental incompatibility. Here we focus on applications where surface transparency is desirable and propose metasurfaces with embedded plasmonically enhanced light absorption heating, using ultrathin hybrid metal-dielectric coatings, as a passive, viable approach for de-icing and anti-icing, in which the sole heat source is renewable solar energy. The balancing of transparency and absorption is achieved with rationally nanoengineered coatings consisting of gold nanoparticle inclusions in a dielectric (titanium dioxide), concentrating broadband absorbed solar energy into a small volume. This causes a > 10 °C temperature increase with respect to ambient at the air-solid interface, where ice is most likely to form, delaying freezing, reducing ice adhesion, when it occurs, to negligible levels (de-icing) and inhibiting frost formation (anti-icing). Our results illustrate an effective unexplored pathway toward environmentally compatible, solar-energy-driven icephobicity, enabled by respectively tailored plasmonic metasurfaces, with the ability to design the balance of transparency and light absorption.

Coronal heating by the resonant absorption of Alfven waves - Importance of the global mode and scaling laws

NASA Technical Reports Server (NTRS)

Steinolfson, Richard S.; Davila, Joseph M.

1993-01-01

Numerical simulations of the MHD equations for a fully compressible, low-beta, resistive plasma are used to study the resonance absorption process for the heating of coronal active region loops. Comparisons with more approximate analytic models show that the major predictions of the analytic theories are, to a large extent, confirmed by the numerical computations. The simulations demonstrate that the dissipation occurs primarily in a thin resonance layer. Some of the analytically predicted features verified by the simulations are (a) the position of the resonance layer within the initial inhomogeneity; (b) the importance of the global mode for a large range of loop densities; (c) the dependence of the resonance layer thickness and the steady-state heating rate on the dissipation coefficient; and (d) the time required for the resonance layer to form. In contrast with some previous analytic and simulation results, the time for the loop to reach a steady state is found to be the phase-mixing time rather than a dissipation time. This disagreement is shown to result from neglect of the existence of the global mode in some of the earlier analyses. The resonant absorption process is also shown to behave similar to a classical driven harmonic oscillator.

Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

PubMed

Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

2014-09-20

This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

The complex refractive index of atmospheric and model humic-like substances (HULIS) retrieved by a cavity ring down aerosol spectrometer (CRD-AS).

PubMed

Dinar, E; Riziq, A Abo; Spindler, C; Erlick, C; Kiss, G; Rudich, Y

2008-01-01

Atmospheric aerosols absorb and reflect solar radiation causing surface cooling and heating of the atmosphere. The interaction between aerosols and radiation depends on their complex index of refraction, which is related to the particles' chemical composition. The contribution of light absorbing organic compounds, such as HUmic-LIke Substances (HULIS) to aerosol scattering and absorption is among the largest uncertainties in assessing the direct effect of aerosols on climate. Using a Cavity Ring Down Aerosol Spectrometer (CRD-AS), the complex index of refraction of aerosols containing HULIS extracted from pollution, smoke, and rural continental aerosols, and molecular weight-fractionated fulvic acid was measured at 390 nm and 532 nm. The imaginary part of the refractive index (absorption) substantially increases towards the UV range with increasing molecular weight and aromaticity. At both wavelengths, HULIS extracted from pollution and smoke particles absorb more than HULIS from the rural aerosol. Sensitivity calculations for a pollution-type aerosol containing ammonium sulfate, organic carbon (HULIS), and soot suggests that accounting for absorption by HULIS leads in most cases to a significant decrease in the single scattering albedo and to a significant increase in aerosol radiative forcing efficiency, towards more atmospheric absorption and heating. This indicates that HULIS in biomass smoke and pollution aerosols, in addition to black carbon, can contribute significantly to light absorption in the ultraviolet and visible spectral regions.

Cobalt Oxide Nanoclusters on Rutile Titania as Bifunctional Units for Water Oxidation Catalysis and Visible Light Absorption: Understanding the Structure-Activity Relationship.

PubMed

Maeda, Kazuhiko; Ishimaki, Koki; Okazaki, Megumi; Kanazawa, Tomoki; Lu, Daling; Nozawa, Shunsuke; Kato, Hideki; Kakihana, Masato

2017-02-22

The structure of cobalt oxide (CoO x ) nanoparticles dispersed on rutile TiO 2 (R-TiO 2 ) was characterized by X-ray diffraction, UV-vis-NIR diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray absorption fine-structure spectroscopy, and X-ray photoelectron spectroscopy. The CoO x nanoparticles were loaded onto R-TiO 2 by an impregnation method from an aqueous solution containing Co(NO 3 ) 2 ·6H 2 O followed by heating in air. Modification of the R-TiO 2 with 2.0 wt % Co followed by heating at 423 K for 1 h resulted in the highest photocatalytic activity with good reproducibility. Structural analyses revealed that the activity of this photocatalyst depended strongly on the generation of Co 3 O 4 nanoclusters with an optimal distribution. These nanoclusters are thought to interact with the R-TiO 2 surface, resulting in visible light absorption and active sites for water oxidation.

Human skin absorption of Bis-2-(chloroethyl)sulphide (sulphur mustard) in vitro.

PubMed

Chilcott, R P; Jenner, J; Carrick, W; Hotchkiss, S A; Rice, P

2000-01-01

The purpose of this study was to measure the absorption and intra-epidermal fate of 35S-radiolabelled sulphur mustard (35SM) in human breast skin in vitro. Skin (full-thickness or heat-separated epidermis) was placed into static diffusion cells and was exposed to droplets of liquid 35SM or saturated 35SM vapour. Amounts of 35SM penetrating the skin were measured from which skin absorption rates were calculated. Unbound radiolabel was washed from the surface, extracted from the skin and analysed to determine the identity of the radiolabelled species in order to measure the extent of hydrolysis of sulphur mustard. Penetration rates of liquid 35SM measured in vitro (71-294 microg cm(-2) h(-1)) were in agreement with those measured previously in vivo using human volunteers (60-240 microg cm(-2) h(-1)). Rates of liquid 35SM skin absorption under occluded, infinite dose conditions were highest through heat-separated epidermal membranes (294+/-58 microg cm(-2) h(-1)) and lowest through full-thickness skin (71+/-14 microg cm(-2) h(-1)). Fluxes of saturated 35SM vapour (110+/-75 microg cm(-2) h(-1)) through heat-separated membranes were similar to those previously measured through human forearm skin in vivo (162 microg cm(-2) h(-1)). Although hydrolysis of 35SM did occur, both on the surface and within the skin, it accounted for only a small percentage of the total applied dose (<2.7+/-1.2%). The difference in total amount of liquid 35SM penetrated between occluded and unoccluded conditions in vitro (79+/-14%) was similar to that lost as vapour from unoccluded skin in vivo (80%). A substantial reservoir of 35SM (14-36% of the applied dose) was measured within heat-separated epidermal membranes for up to 24 h which may have significant implications for the management of personnel exposed to sulphur mustard.

Measurement of electron-ion relaxation in warm dense copper

DOE PAGES

Cho, B. I.; Ogitsu, T.; Engelhorn, K.; ...

2016-01-06

Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. As a result, data are compared with various theoretical models.

Influence of PCMs in thermal insulation on thermal behaviour of building envelopes

NASA Astrophysics Data System (ADS)

Dydek, K.; Furmański, P.; Łapka, P.

2016-09-01

A model of heat transfer through a wall consisting of a layer of concrete and PCM enhanced thermal insulation is considered. The model accounts for heat conduction in both layers, thermal radiation and heat absorption/release due to phase change in the insulation as well as time variation in the ambient temperature and insolation. Local thermal equilibrium between encapsulated PCM and light-weight thermal insulation was assumed. Radiation emission, absorption and scattering were also accounted for in the model. Comparison of different cases of heat flow through the building envelope was carried out. These cases included presence or absence of PCM and thermal radiation in the insulation, effect of emissivity of the PCM microcapsules as well as an effect of solar radiation or its lack on the ambient side of the envelope. Two ways of the PCM distribution in thermal insulation were also considered. The results of simulations were presented for conditions corresponding to the mean summer and winter seasons in Warsaw. It was found that thermal radiation plays an important role in heat transfer through thermal insulation layer of the wall while the presence of the PCM in it significantly contributes to damping of temperature fluctuations and a decrease in heat fluxes flowing into or lost by the interior of the building. The similar effect was observed for a decrease in emissivity of the microcapsules containing PCM.

Phase change material thermal capacitor clothing

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2005-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Phase change thermal control materials, method and apparatus

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2001-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Correlations between Crystallite Size, Shape, Surface, and Infrared Spectra Using the Ti-C System

NASA Astrophysics Data System (ADS)

Kimura, Y.; Ikegami, A.; Kurumada, M.; Kamitsuji, K.; Kaito, C.

2004-06-01

TiC crystallites less than 10 nm in size showed an absorption feature at 14.3 μm. This 14.3 μm absorption was rarely seen in specimens ranging from bulk material to grains of 50 nm in size. The 14.3 μm feature was weakened as a result of the growth of TiC crystallites by heat treatment. When the carbide grains were covered with a carbon layer, the absorption peaks were considerably weakened, i.e., the absorption intensity depended on the grain surface state. A possible explanation is that the effects of size and shape on the spectra depend on the surface anisotropy.

Bottom Extreme-Ultraviolet-Sensitive Coating for Evaluation of the Absorption Coefficient of Ultrathin Film

NASA Astrophysics Data System (ADS)

Hijikata, Hayato; Kozawa, Takahiro; Tagawa, Seiichi; Takei, Satoshi

2009-06-01

A bottom extreme-ultraviolet-sensitive coating (BESC) for evaluation of the absorption coefficients of ultrathin films such as extreme ultraviolet (EUV) resists was developed. This coating consists of a polymer, crosslinker, acid generator, and acid-responsive chromic dye and is formed by a conventional spin-coating method. By heating the film after spin-coating, a crosslinking reaction is induced and the coating becomes insoluble. A typical resist solution can be spin-coated on a substrate covered with the coating film. The evaluation of the linear absorption coefficients of polymer films was demonstrated by measuring the EUV absorption of BESC substrates on which various polymers were spin-coated.

Measurement of H/H+D Ratio and Recycling in Ion Cyclotron Resonance Heating HT-6M Tokamak

NASA Astrophysics Data System (ADS)

Ding, Liancheng; Jiang, Guangkuan; Wei, Lehan

1994-12-01

A scanning Fabry-Perot interferometer has been used to measure the Hα and Dα lines obtain the H/H+D ratio in ion cyclotron resonance heating HT-6M tokamak for determing the energy absorption mechanism. The recycling is observed by changing the working gas from deuterium to hydrogen.

Aerosol Absorption Measurements from LANDSAT and CIMEL

NASA Technical Reports Server (NTRS)

Kaufman, Y. J.; Tanre, D.; Karnieli, A.; Remer, L.; Holben, B.

1999-01-01

Spectral remote observations of dust properties from space and from the ground create a powerful tool for determination of dust absorption of solar radiation with an unprecedented accuracy. Absorption is a key component in understanding dust impact on climate. We use Landsat space-borne measurements at 0.47 to 2.2 micrometer over Senegal with ground-based sunphotometers to find that Saharan dust absorption of solar radiation is two to four times smaller than in models. Though dust absorbs in the blue, almost no absorption was found for wavelengths greater than 0.6 micrometer. The new finding increases by 50% recent estimated solar radiative forcing by dust and decreases the estimated dust heating of the lower troposphere. Dust transported from Asia shows slightly higher absorption probably due to the presence of black carbon from populated regions. Large-scale application of this method to satellite data from the Earth Observing System can reduce significantly the uncertainty in the dust radiative effects.

Calculation of the radiative heat exchange in a conical cavity of complex configuration with an absorptive medium

NASA Technical Reports Server (NTRS)

Surinov, Y. A.; Fedyanin, V. E.

1975-01-01

The generalized zonal method is used to calculate the distribution of the temperature factor on the lateral surface of a conical cavity of complex configuration (a Laval nozzle) containing an absorptive medium. The highest values of the radiation density occur on the converging part of the lateral surface of the complex conical cavity (Laval nozzle).

A two-beam acoustic system for tissue analysis.

PubMed

Sachs, T D; Janney, C D

1977-03-01

In the 'thermo-acoustic sensing technique' (TAST), a burst of sound, called the 'thermometer' beam is passed through tissue and its transit time is measured. A focused sound field, called the heating field, then warms a small volume in the path of the therometer beam, in proportion to the absorption. Finally, the therometer beam burst is repeated and its transit time subtracted from that of the initial thermometer burst. This difference measures the velocity perturbation in the tissue produced by the heating field. The transit time difference is td = K integral of infinity-infinity IP dchi where K is the instrument constant, I the heating field intensity, and P a perturbation factor which characterizes the tissues. The integration is carried out along the path of the thermometer beam. The perturbation factor is P = (formula: see text) where C is the specific heat, rho the denisty, V the velocity of sound, (formula: see text) the temperature coefficient of velocity and alpha the heating field absorption coefficient which is apparently sensitive to tissue structure and condition. Experiments on a fixed human brain showed an ability to distinguish between various tissue types combined with a spatial resolution of better than 3 mm. Should predictions based on the data and theory prove correct, TAST may become a non-invasive alternative to biopsy.

Incipient fire detection system

DOEpatents

Brooks, Jr., William K.

1999-01-01

A method and apparatus for an incipient fire detection system that receives gaseous samples and measures the light absorption spectrum of the mixture of gases evolving from heated combustibles includes a detector for receiving gaseous samples and subjecting the samples to spectroscopy and determining wavelengths of absorption of the gaseous samples. The wavelengths of absorption of the gaseous samples are compared to predetermined absorption wavelengths. A warning signal is generated whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. The method includes receiving gaseous samples, subjecting the samples to light spectroscopy, determining wavelengths of absorption of the gaseous samples, comparing the wavelengths of absorption of the gaseous samples to predetermined absorption wavelengths and generating a warning signal whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. In an alternate embodiment, the apparatus includes a series of channels fluidically connected to a plurality of remote locations. A pump is connected to the channels for drawing gaseous samples into the channels. A detector is connected to the channels for receiving the drawn gaseous samples and subjecting the samples to spectroscopy. The wavelengths of absorption are determined and compared to predetermined absorption wavelengths is provided. A warning signal is generated whenever the wavelengths correspond.

Ab Initio Modeling of Molecular Radiation

NASA Technical Reports Server (NTRS)

Jaffe, Richard; Schwenke, David

2014-01-01

Radiative emission from excited states of atoms and molecules can comprise a significant fraction of the total heat flux experienced by spacecraft during atmospheric entry at hypersonic speeds. For spacecraft with ablating heat shields, some of this radiative flux can be absorbed by molecular constituents in the boundary layer that are formed by the ablation process. Ab initio quantum mechanical calculations are carried out to predict the strengths of these emission and absorption processes. This talk will describe the methods used in these calculations using, as examples, the 4th positive emission bands of CO and the 1g+ 1u+ absorption in C3. The results of these calculations are being used as input to NASA radiation modeling codes like NeqAir, HARA and HyperRad.

High temperature solar photon engines. [heat engines for terrestrial and space-based solar power plants

NASA Technical Reports Server (NTRS)

Hertzberg, A.; Decher, R.; Mattick, A. T.; Lau, C. V.

1978-01-01

High temperature heat engines designed to make maximum use of the thermodynamic potential of concentrated solar radiation are described. Plasmas between 2000 K and 4000 K can be achieved by volumetric absorption of radiation in alkali metal vapors, leading to thermal efficiencies up to 75% for terrestrial solar power plants and up to 50% for space power plants. Two machines capable of expanding hot plasmas using practical technology are discussed. A binary Rankine cycle uses fluid mechanical energy transfer in a device known as the 'Comprex' or 'energy exchanger.' The second machine utilizes magnetohydrodynamics in a Brayton cycle for space applications. Absorption of solar energy and plasma radiation losses are investigated for a solar superheater using potassium vapor.

Thermal microphotonic sensor and sensor array

DOEpatents

Watts, Michael R [Albuquerque, NM; Shaw, Michael J [Tijeras, NM; Nielson, Gregory N [Albuquerque, NM; Lentine, Anthony L [Albuquerque, NM

2010-02-23

A thermal microphotonic sensor is disclosed for detecting infrared radiation using heat generated by the infrared radiation to shift the resonant frequency of an optical resonator (e.g. a ring resonator) to which the heat is coupled. The shift in the resonant frequency can be determined from light in an optical waveguide which is evanescently coupled to the optical resonator. An infrared absorber can be provided on the optical waveguide either as a coating or as a plate to aid in absorption of the infrared radiation. In some cases, a vertical resonant cavity can be formed about the infrared absorber to further increase the absorption of the infrared radiation. The sensor can be formed as a single device, or as an array for imaging the infrared radiation.

Method and apparatus for simulating atomospheric absorption of solar energy due to water vapor and CO.sub.2

DOEpatents

Sopori, Bhushan L.

1995-01-01

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth's surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO.sub.2 and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO.sub.2 and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO.sub.2 and moisture.

Method and apparatus for simulating atmospheric absorption of solar energy due to water vapor and CO{sub 2}

DOEpatents

Sopori, B.L.

1995-06-20

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth`s surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO{sub 2} and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO{sub 2} and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO{sub 2} and moisture. 8 figs.

Determination of trace elements in metals and alloys by atomic-absorption spectroscopy using an induction-heated graphite well furnace as atom source.

PubMed

Headridge, J B; Smith, D R

1972-07-01

An induction-heated graphite furnace, coupled to a Unicam SP 90 atomic-absorption spectrometer, is described for the direct determination of trace elements in metals and alloys. The furnace is capable of operation at temperatures up to 2400 degrees , and has been used to obtain calibration graphs for the determination of ppm quantities of bismuth in lead-base alloys, cast irons and stainless steels, and for the determination of cadmium at the ppm level in zinc-base alloys. Milligram samples of the alloys were atomized directly. Calibration graphs for the determination of the elements in solutions were obtained for comparison. The accuracy and precision of the determination are presented and discussed.

Galactic wind X-ray heating of the intergalactic medium during the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Meiksin, Avery; Khochfar, Sadegh; Paardekooper, Jan-Pieter; Dalla Vecchia, Claudio; Kohn, Saul

2017-11-01

The diffuse soft X-ray emissivity from galactic winds is computed during the Epoch of Reionization (EoR). We consider two analytic models, a pressure-driven wind and a superbubble model, and a 3D cosmological simulation including gas dynamics from the First Billion Years (FiBY) project. The analytic models are normalized to match the diffuse X-ray emissivity of star-forming galaxies in the nearby Universe. The cosmological simulation uses physically motivated star formation and wind prescriptions, and includes radiative transfer corrections. The models and the simulation all are found to produce sufficient heating of the intergalactic medium to be detectable by current and planned radio facilities through 21 cm measurements during the EoR. While the analytic models predict a 21 cm emission signal relative to the cosmic microwave backgroundsets in by ztrans ≃ 8-10, the predicted signal in the FiBY simulation remains in absorption until reionization completes. The 21 cm absorption differential brightness temperature reaches a minimum of ΔT ≃ -130 to -200 mK, depending on model. Allowing for additional heat from high-mass X-ray binaries pushes the transition to emission to ztrans ≃ 10-12, with shallower absorption signatures having a minimum of ΔT ≃ -110 to -140 mK. The 21 cm signal may be a means of distinguishing between the wind models, with the superbubble model favouring earlier reheating. While an early transition to emission may indicate X-ray binaries dominate the reheating, a transition to emission as early as ztrans > 12 would suggest the presence of additional heat sources.

The impact of frequency on the performance of microwave ablation.

PubMed

Sawicki, James F; Shea, Jacob D; Behdad, Nader; Hagness, Susan C

2017-02-01

The use of higher frequencies in percutaneous microwave ablation (MWA) may offer compelling interstitial antenna design advantages over the 915 MHz and 2.45 GHz frequencies typically employed in current systems. To evaluate the impact of higher frequencies on ablation performance, we conducted a comprehensive computational and experimental study of microwave absorption and tissue heating as a function of frequency. We performed electromagnetic and thermal simulations of MWA in ex vivo and in vivo porcine muscle at discrete frequencies in the 1.9-26 GHz range. Ex vivo ablation experiments were performed in the 1.9-18 GHz range. We tracked the size of the ablation zone across frequency for constant input power and ablation duration. Further, we conducted simulations to investigate antenna feed line heating as a function of frequency, input power, and cable diameter. As the frequency was increased from 1.9 to 26 GHz the resulting ablation zone dimensions decreased in the longitudinal direction while remaining relatively constant in the radial direction; thus at higher frequencies the overall ablation zone was more spherical. However, cable heating at higher frequencies became more problematic for smaller diameter cables at constant input power. Comparably sized ablation zones are achievable well above 1.9 GHz, despite increasingly localised power absorption. Specific absorption rate alone does not accurately predict ablation performance, particularly at higher frequencies where thermal diffusion plays an important role. Cable heating due to ohmic losses at higher frequencies may be controlled through judicious choices of input power and cable diameter.

[Purification of complicated industrial organic waste gas by complex absorption].

PubMed

Chen, Ding-Sheng; Cen, Chao-Ping; Tang, Zhi-Xiong; Fang, Ping; Chen, Zhi-Hang

2011-12-01

Complicated industrial organic waste gas with the characteristics of low concentration,high wind volume containing inorganic dust and oil was employed the research object by complex absorption. Complex absorption mechanism, process flow, purification equipment and engineering application were studied. Three different surfactants were prepared for the composite absorbent to purify exhaust gas loaded with toluene and butyl acetate, respectively. Results show that the low surface tension of the composite absorbent can improve the removal efficiency of toluene and butyl acetate. With the advantages of the water film, swirl plate and fill absorption device, efficient absorption equipment was developed for the treatment of complicated industrial organic waste gas. It is with superiorities of simple structure, small size, anti-jam and high mass transfer. Based on absorption technology, waste gas treatment process integrated with heating stripping, burning and anaerobic and other processes, so that emissions of waste gas and absorption solution could meet the discharge standards. The technology has been put into practice, such as manufacturing and spraying enterprises.

Determination of the heat of hydride formation/decomposition by high-pressure differential scanning calorimetry (HP-DSC).

PubMed

Rongeat, Carine; Llamas-Jansa, Isabel; Doppiu, Stefania; Deledda, Stefano; Borgschulte, Andreas; Schultz, Ludwig; Gutfleisch, Oliver

2007-11-22

Among the thermodynamic properties of novel materials for solid-state hydrogen storage, the heat of formation/decomposition of hydrides is the most important parameter to evaluate the stability of the compound and its temperature and pressure of operation. In this work, the desorption and absorption behaviors of three different classes of hydrides are investigated under different hydrogen pressures using high-pressure differential scanning calorimetry (HP-DSC). The HP-DSC technique is used to estimate the equilibrium pressures as a function of temperature, from which the heat of formation is derived. The relevance of this procedure is demonstrated for (i) magnesium-based compounds (Ni-doped MgH2), (ii) Mg-Co-based ternary hydrides (Mg-CoHx) and (iii) Alanate complex hydrides (Ti-doped NaAlH4). From these results, it can be concluded that HP-DSC is a powerful tool to obtain a good approximation of the thermodynamic properties of hydride compounds by a simple and fast study of desorption and absorption properties under different pressures.

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

Sun, Xingshu; Silverman, Timothy J.; Zhou, Zhiguang

For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 °C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of photovoltaic (PV) modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of themore » solar module to eliminate parasitic absorption (selective-spectral cooling) and enhance thermal emission (radiative cooling). Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool one-sun terrestrial solar modules up to 10 °C. As a result, this self-cooling would substantially extend the lifetime for solar modules, with corresponding increase in energy yields and reduced levelized cost of electricity.« less

SYNCHROTRON HEATING BY A FAST RADIO BURST IN A SELF-ABSORBED SYNCHROTRON NEBULA AND ITS OBSERVATIONAL SIGNATURE

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

Yang, Yuan-Pei; Dai, Zi-Gao; Zhang, Bing, E-mail: zhang@physics.unlv.edu

Fast radio bursts (FRBs) are mysterious transient sources. If extragalactic, as suggested by their relative large dispersion measures, their brightness temperatures must be extremely high. Some FRB models (e.g., young pulsar model, magnetar giant flare model, or supra-massive neutron star collapse model) suggest that they may be associated with a synchrotron nebula. Here we study a synchrotron-heating process by an FRB in a self-absorbed synchrotron nebula. If the FRB frequency is below the synchrotron self-absorption frequency of the nebula, electrons in the nebula would absorb FRB photons, leading to a harder electron spectrum and enhanced self-absorbed synchrotron emission. In themore » meantime, the FRB flux is absorbed by the nebula electrons. We calculate the spectra of FRB-heated synchrotron nebulae, and show that the nebula spectra would show a significant hump in several decades near the self-absorption frequency. Identifying such a spectral feature would reveal an embedded FRB in a synchrotron nebula.« less

An Axisymmetric Hydrodynamical Model for the Torus Wind in AGN. 2; X-ray Excited Funnel Flow

NASA Technical Reports Server (NTRS)

Dorodnitsyn, A.; Kallman, T.; Proga, D.

2008-01-01

We have calculated a series of models of outflows from the obscuring torus in active galactic nuclei (AGN). Our modeling assumes that the inner face of a rotationally supported torus is illuminated and heated by the intense X-rays from the inner accretion disk and black hole. As a result of such heating a strong biconical outflow is observed in our simulations. We calculate 3-dimensional hydrodynamical models, assuming axial symmetry, and including the effects of X-ray heating, ionization, and radiation pressure. We discuss the behavior of a large family of these models, their velocity fields, mass fluxes and temperature, as functions of the torus properties and X-ray flux. Synthetic warm absorber spectra are calculated, assuming pure absorption, for sample models at various inclination angles and observing times. We show that these models have mass fluxes and flow speeds which are comparable to those which have been inferred from observations of Seyfert 1 warm absorbers, and that they can produce rich absorption line spectra.

[Clothing and heat disorder].

PubMed

Satsumoto, Yayoi

2012-06-01

The influence of the clothing material properties(like water absorbency and rapid dryness, water vapor absorption, water vapor permeability and air permeability) and the design factor of the clothing(like opening condition and fitting of clothing), which contributed to prevent heat disorder, was outlined. WBGT(wet-bulb globe temperature) is used to show a guideline for environmental limitation of activities to prevent heat disorder. As the safety function is more important than thermal comfort for some sportswear and protective clothing with high cover area, clothing itself increases the risk of heat disorder. WBGT is corrected by CAF (clothing adjustment factor) in wearing such kind of protective clothing.

Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

NASA Technical Reports Server (NTRS)

1980-01-01

The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

Electron-cyclotron resonance preionization and heating in the Proto-cleo torsatron

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

Goes, L.C.S.

1986-01-01

ECR-breakdown and heating in a bifurcated torsatron topology are investigated with extraordinary mode injection from the high-field side (7.2 GHz/2 KW/10 ms). The breakdown characteristics are explained by stochastic heating enhanced by helical ripple effects. In the quasi-stationary regime (0.01 n/sub cr/ < n < 0.6 n/sub cr/), two-dimensional plasma profiles indicated heating inhomogeneities associated with RF power absorption near the UHR layer. The production of a suprathermal electron population, at the outer plasma edge, was indicated by nonthermal microwave emission and target SXR emission.

Thermally induced coloration of KBr at high pressures

NASA Astrophysics Data System (ADS)

Arveson, Sarah M.; Kiefer, Boris; Deng, Jie; Liu, Zhenxian; Lee, Kanani K. M.

2018-03-01

Laser-heated diamond-anvil cell (LHDAC) experiments reveal electronic changes in KBr at pressures between ˜13 -81 GPa when heated to high temperatures that cause runaway heating to temperatures in excess of ˜5000 K . The drastic changes in absorption behavior of KBr are interpreted as rapid formation of high-pressure F-center defects. The defects are localized to the heated region and thus do not change the long-range crystalline order of KBr. The results have significant consequences for temperature measurements in LHDAC experiments and extend the persistence of F centers in alkali halides to at least 81 GPa.

A model of the SO2 atmosphere and ionosphere of Io

NASA Technical Reports Server (NTRS)

Kumar, S.

1980-01-01

The calculations of thermal structure for an SO2 atmosphere of Io lead to exospheric temperatures in 800-1200 K range. The Pioneer 10 electron density profiles can be fit with an SO2 surface density of 1.2 x 10 to the 11th per cu cm at 5:30 pm local time and exosphere temperature of 1030 K. Low energy electrons provide the major ionization source but the solar UV absorption dominates the heating of the atmosphere due to the long wavelength absorption threshold of SO2 and large absorption cross sections.

Tunable diode-laser absorption measurements of methane at elevated temperatures

NASA Astrophysics Data System (ADS)

Nagali, V.; Chou, S. I.; Baer, D. S.; Hanson, R. K.; Segall, J.

1996-07-01

A diode-laser sensor system based on absorption spectroscopy techniques has been developed to monitor CH4 nonintrusively in high-temperature environments. Fundamental spectroscopic parameters, including the line strengths of the transitions in the R(6) manifold of the 2 nu 3 band near 1.646 mu m, have been determined from high-resolution absorption measurements in a heated static cell. In addition, a corrected expression for the CH 4 partition function has been validated experimentally over the temperature range from 400 to 915 K. Potential applications of the diode-laser sensor system include process control, combustion measurements, and atmospheric monitoring.

Process Studies on Laser Welding of Copper with Brilliant Green and Infrared Lasers

NASA Astrophysics Data System (ADS)

Engler, Sebastian; Ramsayer, Reiner; Poprawe, Reinhart

Copper materials are classified as difficult to weld with state-of-the-art lasers. High thermal conductivity in combination with low absorption at room temperature require high intensities for reaching a deep penetration welding process. The low absorption also causes high sensitivity to variations in surface conditions. Green laser radiation shows a considerable higher absorption at room temperature. This reduces the threshold intensity for deep penetration welding significantly. The influence of the green wavelength on energy coupling during heat conduction welding and deep penetration welding as well as the influence on the weld shape has been investigated.

Cryogenic Thermal Absorptance Measurements on Small-Diameter Stainless Steel Tubing

NASA Technical Reports Server (NTRS)

Tuttle, James; Jahromi, Amir; Canavan, Edgar; DiPirro, Michael

2015-01-01

The Mid Infrared Instrument (MIRI) on the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 Kelvin operating temperature. The coolant gas flows through several meters of small-diameter stainless steel tubing, which is exposed to thermal radiation from its environment. Over much of its length this tubing is gold-plated to minimize the absorption of this radiant heat. In order to confirm that the cryocooler will meet MIRI's requirements, the thermal absorptance of this tubing was measured as a function of its environment temperature. We describe the measurement technique and present the results.

Ultraviolet absorption cross-sections of hot carbon dioxide

NASA Astrophysics Data System (ADS)

Oehlschlaeger, Matthew A.; Davidson, David F.; Jeffries, Jay B.; Hanson, Ronald K.

2004-12-01

The temperature-dependent ultraviolet absorption cross-section for CO 2 has been measured in shock-heated gases between 1500 and 4500 K at 216.5, 244, 266, and 306 nm. Continuous-wave lasers provide the spectral brightness to enable precise time-resolved measurements with the microsecond time-response needed to monitor thermal decomposition of CO 2 at temperatures above 3000 K. The photophysics of the highly temperature dependent cross-section is discussed. The new data allows the extension of CO 2 absorption-based temperature sensing methods to higher temperatures, such as those found in behind detonation waves.

Evanescent wave sensing and absorption analysis of herbal tea floral extracts in the presence of silver metal complexes

NASA Astrophysics Data System (ADS)

Priyamvada, V. C.; Radhakrishnan, P.

2017-06-01

Fiber optic evanescent wave sensors are used for studying the absorption properties of biochemical samples. The studies give precise information regarding the actual ingredients of the samples. Recent studies report the corrosion of silver in the presence glucose dissolved in water and heated to a temperature of 70°C. Based on this report evanescent absorption studies are carried out in hibiscus herbal tea floral extracts in the presence of silver metal complexes. These studies can also lead to the evaluation of the purity of the herbal tea extract.

Modeling of thermoplastic composites laser welding - A ray tracing method associated to thermal simulation

NASA Astrophysics Data System (ADS)

Dauphin, Myriam; Cosson, Benoit

2016-10-01

The importance of the absorption phenomenon occurring into the semi-transparent substrate of reinforced fiber thermoplastic, during the Laser Transmission Welding process (LTW), was examined. A (3D) transient thermal model of LTW was developed. First, the energy distribution coming from the laser irradiation was assessed. Ray tracing techniques allowed us to deal with both absorption and a strong light-scattering caused by the heterogeneity of composite. Then, the energy balance equation was solved in order to study the heating stage. This paper proposes a comparison of the welding area obtained with a model for which absorption was neglected and a second model where absorption was considered. The interest to consider absorption was shown for process optimization purposes and for the use of reinforced composites colored or filled with additives.

Low-redshift Lyman-alpha absorption lines and the dark matter halos of disk galaxies

NASA Technical Reports Server (NTRS)

Maloney, Philip

1992-01-01

Ultraviolet observations of the low-redshift quasar 3C 273 using the Hubble Space Telescope have revealed many more Lyman-alpha absorption lines than would be expected from extrapolation of the absorption systems seen toward QSOs at z about 2. It is shown here that these absorption lines can plausibly be produced by gas at large radii in the disks of spiral and irregular galaxies; the gas is confined by the dark matter halos and ionized and heated by the extragalactic radiation field. This scenario does not require the extragalactic ionizing radiation field to decline as rapidly with decreasing z as the QSO emissivity. Observations of Ly-alpha absorption through the halos of known galaxies at low redshift will constrain both the extragalactic background and the properties of galactic halos.

Effect of the concentration of magnetic grains on the linear-optical-absorption coefficient of ferrofluid-doped lyotropic mesophases: deviation from the Beer-Lambert law.

PubMed

Cuppo, F L S; Gómez, S L; Figueiredo Neto, A M

2004-04-01

In this paper is reported a systematic experimental study of the linear-optical-absorption coefficient of ferrofluid-doped isotropic lyotropic mixtures as a function of the magnetic-grains concentration. The linear optical absorption of ferrolyomesophases increases in a nonlinear manner with the concentration of magnetic grains, deviating from the usual Beer-Lambert law. This behavior is associated to the presence of correlated micelles in the mixture which favors the formation of small-scale aggregates of magnetic grains (dimers), which have a higher absorption coefficient with respect to that of isolated grains. We propose that the indirect heating of the micelles via the ferrofluid grains (hyperthermia) could account for this nonlinear increase of the linear-optical-absorption coefficient as a function of the grains concentration.

High purity silica reflective heat shield development

NASA Technical Reports Server (NTRS)

Blome, J. C.; Drennan, D. N.; Schmitt, R. J.

1974-01-01

Measurements were made of reflectance in the vacuum ultraviolet down to 0.15 micron. Scattering coefficients (S) and absorption coefficients (K) were also measured. These coefficients express the optical properties and are used directly in a thermodynamic analysis for sizing a heat shield. The effect of the thin silica melt layer formed during entry was also studied from the standpoint of trapped radiant energy.

Thermal behavior in the cracking reaction zone of scramjet cooling channels at different channel aspect ratios

NASA Astrophysics Data System (ADS)

Zhang, Silong; Feng, Yu; Jiang, Yuguang; Qin, Jiang; Bao, Wen; Han, Jiecai; Haidn, Oskar J.

2016-10-01

To study the thermal behavior in the cracking reaction zone of regeneratively cooled scramjet cooling channels at different aspect ratios, 3-D model of fuel flow in terms of the fuel's real properties and cracking reaction is built and validated through experiments. The whole cooling channel is divided into non-cracking and cracking reaction zones. Only the cracking reaction zone is studied in this article. The simulation results indicate that the fuel conversion presents a similar distribution with temperature because the fuel conversion in scramjet cooling channels is co-decided by the temperature and velocity but the temperature plays the dominate role. For the cases given in this paper, increasing the channel aspect ratio will increase the pressure drop and it is not beneficial for reducing the wall temperature because of the much severer thermal stratification, larger conversion non-uniformity, the corresponding M-shape velocity profile which will cause local heat transfer deterioration and the decreased chemical heat absorption. And the decreased chemical heat absorption caused by stronger temperature and conversion non-uniformities is bad for the utilization of chemical heat sink, chemical recuperation process and the ignition performance.

RF heating of nanoclusters for cancer therapy

NASA Astrophysics Data System (ADS)

Letfullin, Renat R.; Letfullin, Alla R.; George, Thomas F.

2015-03-01

Nanodrugs selectively delivered to a tumor site can be activated by radiation for drug release, or nanoparticles (NPs) can be used as a drug themselves by producing biological damage in cancer cells through thermal, mechanical ablations or charged particle emission. Radio-frequency (RF) waves have an excellent ability to penetrate into the human body without causing healthy tissue damage, which provides a great opportunity to activate/heat NPs delivered inside the body as a contrast agent for diagnosis and treatment purposes. However the heating of NPs in the RF range of the spectrum is controversial in the research community because of the low power load of RF waves and low absorption of NPs in the RF range. To resolve these weaknesses in the RF activation of NPs and dramatically increase absorption of contrast agents in tumor, we suggest aggregating the nanoclusters inside or on the surface of the cancer cells. We simulate space distribution of temperature changes inside and outside metal and dielectric nanopraticles/nanoclusters, determine the number of nanoparticles needed to form a cluster, and estimate the thermal damage area produced in surrounding medium by nanopraticles/nanoclusters heated in the RF field.

On the sub-band gap optical absorption in heat treated cadmium sulphide thin film deposited on glass by chemical bath deposition technique

NASA Astrophysics Data System (ADS)

Chattopadhyay, P.; Karim, B.; Guha Roy, S.

2013-12-01

The sub-band gap optical absorption in chemical bath deposited cadmium sulphide thin films annealed at different temperatures has been critically analyzed with special reference to Urbach relation. It has been found that the absorption co-efficient of the material in the sub-band gap region is nearly constant up to a certain critical value of the photon energy. However, as the photon energy exceeds the critical value, the absorption coefficient increases exponentially indicating the dominance of Urbach rule. The absorption coefficients in the constant absorption region and the Urbach region have been found to be sensitive to annealing temperature. A critical examination of the temperature dependence of the absorption coefficient indicates two different kinds of optical transitions to be operative in the sub-band gap region. After a careful analyses of SEM images, energy dispersive x-ray spectra, and the dc current-voltage characteristics, we conclude that the absorption spectra in the sub-band gap domain is possibly associated with optical transition processes involving deep levels and the grain boundary states of the material.

Efficiency of Microwave Heating of Weakly Loaded Polymeric Nanocomposites (Postprint)

DTIC Science & Technology

2012-05-10

shielding and radar absorption [5]. Interaction of carbon nanotubes with microwaves is a subject of active ongoing research, 2 and the...mechanism of the microwave absorption by carbon nanotubes is still poorly understood [6-8]. Low thermal conductivity materials with controlled...and RAS design simulation. Composites Science and Technology. 70(2): p. 400‐409. 6. Vázquez, E. and M. Prato, Carbon Nanotubes and

Manganese dioxide causes spurious gold values in flame atomic-absorption readings from HBr-Br2 digestions

USGS Publications Warehouse

Campbell, W.L.

1981-01-01

False readings, apparently caused by the presence of high concentrations of manganese dioxide, have been observed in our current flame atomic-absorption procedure for the determination of gold. After a hydrobromic acid (HBr)-bromine (Br2) leach, simply heating the sample to boiling to remove excess Br2 prior to extraction with methyl-isobutyl-ketone (MIBK) eliminates these false readings. ?? 1981.

Controlling Corrosion in Defence Equipment - Technical Meeting,

DTIC Science & Technology

1985-10-01

methods identify elements. (c) IR absorption spectroscopy. % e The identifies radicals, sometimes compounds. X-ray fluorescence and atomic absorption ...components from this radio. There were 100 sets all with defective - silver plating, with a total value of $5 million. A method of refurbishment was...Assemblies from the FiiC Aircraft Slides of a corroded heat exchanger assembly were shown. A method of refurbishment was suggested. Estimated saving - $0.5

Rapid determination of nanogram amounts of tellurium in silicate rocks

USGS Publications Warehouse

Greenland, L.P.; Campbell, E.Y.

1976-01-01

A hydride-generation flameless atomic-absorption technique is used to determine as little as 5 ng g-1 tellurium in 0.25 g of silicate rock. After acid decomposition of the sample, tellurium hydride is generated with sodium borohydride and the vapor passed directly to a resistance-heated quartz cell mounted in an atomic-absorption spectrophotometer. Analyses of 11 U.S. Geological Survey standard rocks are presented. ?? 1976.

Analysis of Heat Transfer Phenomenon in Magnetohydrodynamic Casson Fluid Flow Through Cattaneo-Christov Heat Diffusion Theory

NASA Astrophysics Data System (ADS)

Ramesh, G. K.; Gireesha, B. J.; Shehzad, S. A.; Abbasi, F. M.

2017-07-01

Heat transport phenomenon of two-dimensional magnetohydrodynamic Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated in the mathematical modeling of present flow problem. The governing mathematical expressions are solved for velocity and temperature profiles using RKF 45 method along with shooting technique. The importance of arising nonlinear quantities namely velocity, temperature, skin-friction and temperature gradient are elaborated via plots. It is explored that the Casson parameter retarded the liquid velocity while it enhances the fluid temperature. Further, we noted that temperature and thickness of temperature boundary layer are weaker in case of Cattaneo-Christov heat diffusion model when matched with the profiles obtained for Fourier’s theory of heat flux.

Effects of Radiative Emission and Absorption on the Propagation and Extinction of Premixed Gas Flames

NASA Technical Reports Server (NTRS)

Ju, Yiguang; Masuya, Goro; Ronney, Paul D.

1998-01-01

Premixed gas flames in mixtures of CH4, O2, N2, and CO2 were studied numerically using detailed chemical and radiative emission-absorption models to establish the conditions for which radiatively induced extinction limits may exist independent of the system dimensions. It was found that reabsorption of emitted radiation led to substantially higher burning velocities and wider extinction limits than calculations using optically thin radiation models, particularly when CO2, a strong absorber, is present in the unburned gas, Two heat loss mechanisms that lead to flammability limits even with reabsorption were identified. One is that for dry hydrocarbon-air mixtures, because of the differences in the absorption spectra of H2O and CO2, most of the radiation from product H2O that is emitted in the upstream direction cannot be absorbed by the reactants. The second is that the emission spectrum Of CO2 is broader at flame temperatures than ambient temperature: thus, some radiation emitted near the flame front cannot be absorbed by the reactants even when they are seeded with CO2 Via both mechanisms, some net upstream heat loss due to radiation will always occur, leading to extinction of sufficiently weak mixtures. Downstream loss has practically no influence. Comparison with experiment demonstrates the importance of reabsorption in CO2 diluted mixtures. It is concluded that fundamental flammability limits can exist due to radiative heat loss, but these limits are strongly dependent on the emission-absorption spectra of the reactant and product -gases and their temperature dependence and cannot be predicted using gray-gas or optically thin model parameters. Applications to practical flames at high pressure, in large combustion chambers, and with exhaust-gas or flue-gas recirculation are discussed.

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

Fares, Hssen; Férid, Mokhtar; Elhouichet, Habib, E-mail: habib.elhouichet@fst.rnu.tn

Tellurite glasses doped Er³⁺ ions and containing Silver nanoparticles (Ag NPs) are prepared using melt quenching technique. The nucleation and growth of Ag NPs were controlled by a thermal annealing process. The X-ray diffraction pattern shows no sharp peak indicating an amorphous nature of the glasses. The presence of Ag NPs is confirmed from transmission electron microscopy micrograph. Absorption spectra show typical surface plasmon resonance (SPR) band of Ag NPs within the 510–550 nm range in addition to the distinctive absorption peaks of Er³⁺ ions. The Judd-Ofelt (J-O) intensity parameters, oscillator strengths, spontaneous transition probabilities, branching ratios, and radiative lifetimesmore » were successfully calculated based on the experimental absorption spectrum and the J-O theory. It was found that the presence of silver NPs nucleated and grown during the heat annealing process improves both of the photoluminescence (PL) intensity and the PL lifetime relative to the ⁴I 13/2 → ⁴I 15/2 transition. Optimum PL enhancement was obtained after 10 h of heat-treatment. Such enhancements are mainly attributed to the strong local electric field induced by SPR of silver NPs and also to energy transfer from the surface of silver NPs to Er³⁺ ions, whereas the quenching is ascribed to the energy transfer from Er³⁺ ions to silver NPs. Using the Mc Cumber method, absorption cross-section, calculated emission cross-section, and gain cross-section for the ⁴I 13/2 → ⁴I 15/2 transition were determined and compared for the doped and co-doped glasses. The present results indicate that the glass heat-treated for 10 h has good prospect as a gain medium applied for 1.53 μm band broad and high-gain erbium-doped fiber amplifiers.« less

A pumped, two-phase flow heat transport system for orbiting instrument payloads

NASA Technical Reports Server (NTRS)

Fowle, A. A.

1981-01-01

A pumped two-phase (heat absorption/heat rejection) thermal transport system for orbiting instrument payloads is investigated. The thermofluid characteristics necessary for the system design are discussed. A preliminary design with a series arrangement of four instrument heat stations and six radiators in a single loop is described in detail, and the total mass is estimated to be 134 kg, with the radiators, instrument heat stations, and fluid reservoir accounting for approximately 86, 24, and 12 kg, respectively. The evaluation of preliminary test results shows that the system has potential advantages; however, further research is necessary in the areas of one-g and zero-g heat transfer coefficients/fluid regimes, fluid by-pass temperature control, and reliability of small pumps.

Analysis of the Factors Contributing to the Heat Observed in Electrochemical Cells used in Condensed Matter Nuclear Science (CMNS)

NASA Astrophysics Data System (ADS)

Al Katrib, Amal K.

This paper discusses two types of study conducted by student in an attempt to support, or refute, hypotheses of possible sources behind the excess heat observed in CMNS experiments. The first study involves a study of over 200 papers in CMNS. This was initiated due to the concern of some critics of CMNS research that small energy changes in many H2O or D2O molecules in electrochemical cells can explain the observed excess heat. It was determined that 65% of the 17 papers that documented excess energy and cell volume values rendered ratios that exceed the vibrational energy of water molecules at room temperature (0.04eV/molecule), with the highest ratio being 43.6eV/molecule. Such ratios are far beyond what is plausible for water to be the source of anomalous heat. Therefore, it is concluded that some unknown rearrangement of water molecules in many CMNS papers is not the source of excess heat. This can be used to rule out the molecular rearrangement hypothesis used to explain the source of observed excess heat, which is the main objective of the first study. Other objectives for the 1st study include the generation of a database of those 335 papers in CMNS and a study of the possibility of any correlation between energy and cell volume based on data extracted from those papers. The second study involves the usage of spectroscopy methods, particularly UV-VIS, in identifying chemical reactions present within a typical CMNS electrochemical cell. Electrolysis of Mel Miles' chemical recipe (a Pd co-deposition system) was conducted. Both absorption and emission measurements were obtained for the overall solution and for the reference chemicals involved in an attempt to find a correlation between spectra and thus determine the specific chemical reactions involved in every stage. The absorption experiment rendered unreliable spectral data due to instrumentation/UV-VIS limitations, concentration effects, environmental factors, and human error. Therefore, it is concluded that absorption offers very little utility in identifying chemical reactions. The emission experiment was initiated but not fully finished; nonetheless, it showed better data, thus rendering it a more viable approach in chemical analysis than absorption. Several vibronic progression and lone peaks were clearly discernable in emission spectra. Without remediation and a follow-up study, recurring instrumentation/UV-VIS issues proscribe drawing conclusions; however, emission shows to be promising and can be later used to conclusively refute, or support, the chemical reactions hypothesis.

Non-uniform temperature and species concentration measurements in a laminar flame using multi-band infrared absorption spectroscopy

NASA Astrophysics Data System (ADS)

Ma, Liu Hao; Lau, Lok Yin; Ren, Wei

2017-03-01

We report in situ measurements of non-uniform temperature, H2O and CO2 concentration distributions in a premixed methane-air laminar flame using tunable diode laser absorption spectroscopy (TDLAS). A mid-infrared, continuous-wave, room-temperature interband cascade laser (ICL) at 4183 nm was used for the sensitive detection of CO2 at high temperature.The H2O absorption lines were exploited by one distributed feedback (DFB) diode laser at 1343 nm and one ICL at 2482 nm to achieve multi-band absorption measurements with high species concentration sensitivity, high temperature sensitivity, and immunity to variations in ambient conditions. A novel profile-fitting function was proposed to characterize the non-uniform temperature and species concentrations along the line-of-sight in the flame by detecting six absorption lines of CO2 and H2O simultaneously. The flame temperature distribution was measured at different heights above the burner (5-20 mm), and compared with the thermocouple measurement with heat-transfer correction. Our TDLAS measured temperature of the central flame was in excellent agreement (<1.5% difference) with the thermocouple data.The TDLAS results were also compared with the CFD simulations using a detailed chemical kinetics mechanism (GRI 3.0) and considering the heat loss to the surroundings.The current CFD simulation overpredicted the flame temperature in the gradient region, but was in excellent agreement with the measured temperature and species concentration in the core of the flame.

Effect of nonlinear absorption on self focusing of short laser pulse in a plasma

NASA Astrophysics Data System (ADS)

Kumar, Ashok

2012-06-01

Paraxial theory of self focusing of short pulse laser in a plasma under transient and saturating effects of nonlinearity and nonlinear absorption is developed. The absorption is averaged over the cross-section of the beam and is different for different time segments of the pulse. The electron temperature includes cumulative effect of previous history of temporal profile of pulse intensity, however, the ambipolar diffusion is taken to be faster than the heating time. The relaxation effect causes self-distortion of the pulse temporal profile where as the nonlinear absorption weakens self focusing. For the pulses of duration comparable to the electron ion collision time, the front part of the pulse gets defocused where as the latter part undergoes periodic self focusing.

Single diode laser sensor for wide-range H2O temperature measurements.

PubMed

Gharavi, Mohammadreza; Buckley, Steven G

2004-04-01

A single diode laser absorption sensor (near 1477 nm) useful for simultaneous temperature and H2O concentration measurements is developed. The diode laser tunes approximately 1.2 cm(-1) over three H2O absorption transitions in each measurement. The line strengths of the transitions are measured over a temperature range from 468 to 977 K, based on high-resolution absorption measurements in a heated static cell. The results indicate that the selected transitions are suitable for sensitive temperature measurements in atmospheric pressure combustion systems using absorption line ratios. Comparing the results with HITRAN 96 data, it appears that these transitions will be sensitive over a wide range of temperatures (450-2000 K), suggesting applicability for combustion measurements.

Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

DOEpatents

Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

2015-04-21

A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

A numerical study of three-dimensional flame propagation over thin solids in purely forced concurrent flow including gas-phase radiation

NASA Astrophysics Data System (ADS)

Feier, Ioan I., Jr.

The effect of flame radiation on concurrent-flow flame spread over a thin solid sample of finite width in a low-speed wind tunnel is modeled using three-dimensional full Navier-Stokes equations and three-dimensional flame radiation transfer equations. The formulation includes the conservation of mass, momentum, energy, and species: fuel vapor, oxygen, carbon dioxide and water vapor. The SN discrete ordinates method is used to solve the radiation transfer equation with a mean absorption coefficient kappa = Ckappa p, where kappap is the Planck mean absorption coefficient of the gas mixture. The varying parameter C has a value between 0 and 1; C represents the strength of flame radiation. In addition, the solid fuel absorptivity alpha is varied to ascertain the effect of flame radiation heat feedback to the solid. The flow tunnel modeled has a dimension of 10x10x30 cm, the solid fuel has a width of 6-cm with two 1-cm inert strips as edges. Incoming forced flow velocity (5 cm/s) of 21% oxygen is assumed. For comparison with the three-dimensional results, corresponding two-dimensional computations are also performed. Detailed spatial flame profiles, solid surface profiles, and heat fluxes are presented. Increasing the flame radiation strength decreases the flame length. Although flame radiation provides an additional heat transfer mechanism to preheat the solid, it is insufficient to offset the decreased convective heating due to the shorter flame; the net effect is a slower spread rate. The percentage of unreacted fuel vapor that escapes from the flame is under 2%. It is theorized that some of the pyrolyzed fuel vapor diffuses sideway and reacts at the flame edges. A radiative energy balance is analyzed also. Flame radiative feedback to the solid plays a more important role in two-dimensional flames. With high solid fuel absorptivity, a peak in the flame spread rate occurs at an intermediate value of flame radiation strength---due to the competition between two mechanisms: gas-radiation heat loss weakening the flame and the radiative feedback boosting the solid pyrolysis. Two-dimensional calculations suggest that a larger percentage of unreacted fuel vapor can escape from the flame when the flame radiation strength is high.

Transient Infrared Emission Spectroscopy

NASA Astrophysics Data System (ADS)

Jones, Roger W.; McClelland, John F.

1989-12-01

Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a very high sample speed would be required to attain a diffusion time of 100 μs. Accordingly, pulsed-laser TIRES generally produces spectra suffering from less self-absorption than cw-laser TIRES does, but the cw-laser technique is technically much simpler since no synchronization is required.

The electrothermal conductance and heat capacity of black phosphorus

NASA Astrophysics Data System (ADS)

Sengupta, Parijat; Das, Saptarshi; Shi, Junxia

2018-03-01

We study a thermal gradient induced current (It h ) flow in potassium-doped two-dimensional anisotropic black phosphorus (BP) with semi-Dirac dispersion. The prototype device is a BP channel clamped between two contacts maintained at unequal temperatures. The choice of BP lies in the predicted efficient thermoelectric behaviour. A temperature-induced difference in the Fermi levels of the two contacts drives the current (typified by the electro-thermal conductance) which we calculate using the Landauer transport equation. The current shows an initial rise when the device is operated at lower temperatures. The rise stalls at progressively higher temperatures and Ith acquires a plateau-like flat profile indicating a competing effect between a larger number of transmission modes and a corresponding drop in the Fermi level difference between the contacts. The current is computed for both n- and p-type BP, and the difference thereof is attributed to the particle-hole asymmetry. The utility of such calculations lie in conversion of the heat produced in a miniaturized chip to useful thermopower via a prototypical Seebeck power generator. Unlike the flow of Ith that purportedly utilizes the additional removable heat in a nanoscale device heat, the ability of a material to maintain a steady temperature is reflected in its heat capacity through effective absorption of thermal energy. The heat capacity is formulated in this work for BP via a Sommerfeld expansion. In the concluding part, we draw a microscopic connection between the two seemingly disparate processes of heat removal and absorption by pinning down their origin to the underlying density of states. Finally, a qualitative analysis of a Carnot-like efficiency of the considered thermoelectric engine is performed drawing upon the previous results on thermal current and heat capacity.

Laser induced heat source distribution in bio-tissues

NASA Astrophysics Data System (ADS)

Li, Xiaoxia; Fan, Shifu; Zhao, Youquan

2006-09-01

During numerical simulation of laser and tissue thermal interaction, the light fluence rate distribution should be formularized and constituted to the source term in the heat transfer equation. Usually the solution of light irradiative transport equation is given in extreme conditions such as full absorption (Lambert-Beer Law), full scattering (Lubelka-Munk theory), most scattering (Diffusion Approximation) et al. But in specific conditions, these solutions will induce different errors. The usually used Monte Carlo simulation (MCS) is more universal and exact but has difficulty to deal with dynamic parameter and fast simulation. Its area partition pattern has limits when applying FEM (finite element method) to solve the bio-heat transfer partial differential coefficient equation. Laser heat source plots of above methods showed much difference with MCS. In order to solve this problem, through analyzing different optical actions such as reflection, scattering and absorption on the laser induced heat generation in bio-tissue, a new attempt was made out which combined the modified beam broaden model and the diffusion approximation model. First the scattering coefficient was replaced by reduced scattering coefficient in the beam broaden model, which is more reasonable when scattering was treated as anisotropic scattering. Secondly the attenuation coefficient was replaced by effective attenuation coefficient in scattering dominating turbid bio-tissue. The computation results of the modified method were compared with Monte Carlo simulation and showed the model provided reasonable predictions of heat source term distribution than past methods. Such a research is useful for explaining the physical characteristics of heat source in the heat transfer equation, establishing effective photo-thermal model, and providing theory contrast for related laser medicine experiments.

The electrothermal conductance and heat capacity of black phosphorus.

PubMed

Sengupta, Parijat; Das, Saptarshi; Shi, Junxia

2018-03-14

We study a thermal gradient induced current I th flow in potassium-doped two-dimensional anisotropic black phosphorus (BP) with semi-Dirac dispersion. The prototype device is a BP channel clamped between two contacts maintained at unequal temperatures. The choice of BP lies in the predicted efficient thermoelectric behaviour. A temperature-induced difference in the Fermi levels of the two contacts drives the current (typified by the electro-thermal conductance) which we calculate using the Landauer transport equation. The current shows an initial rise when the device is operated at lower temperatures. The rise stalls at progressively higher temperatures and I th acquires a plateau-like flat profile indicating a competing effect between a larger number of transmission modes and a corresponding drop in the Fermi level difference between the contacts. The current is computed for both n- and p-type BP, and the difference thereof is attributed to the particle-hole asymmetry. The utility of such calculations lie in conversion of the heat produced in a miniaturized chip to useful thermopower via a prototypical Seebeck power generator. Unlike the flow of I th that purportedly utilizes the additional removable heat in a nanoscale device heat, the ability of a material to maintain a steady temperature is reflected in its heat capacity through effective absorption of thermal energy. The heat capacity is formulated in this work for BP via a Sommerfeld expansion. In the concluding part, we draw a microscopic connection between the two seemingly disparate processes of heat removal and absorption by pinning down their origin to the underlying density of states. Finally, a qualitative analysis of a Carnot-like efficiency of the considered thermoelectric engine is performed drawing upon the previous results on thermal current and heat capacity.

A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

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

Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A.

A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver withmore » only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.« less

Extension of the ECRH operational space with O2 and X3 heating schemes to control tungsten accumulation in ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Höhnle, H.; Stober, J.; Herrmann, A.; Kasparek, W.; Leuterer, F.; Monaco, F.; Neu, R.; Schmid-Lorch, D.; Schütz, H.; Schweinzer, J.; Stroth, U.; Wagner, D.; Vorbrugg, S.; Wolfrum, E.; ASDEX Upgrade Team

2011-08-01

ASDEX Upgrade has been operated with tungsten-coated plasma-facing components for several years. H-mode operation with good confinement has been demonstrated. Nevertheless, purely neutral beam injection-heated H-modes with reduced gas puff, moderate heating power or/and increased triangularity tend to accumulate tungsten, followed by a radiative collapse. Under these conditions, central electron heating with electron cyclotron resonance heating (ECRH), usually in X2 polarization, changes the impurity transport in the plasma centre, reducing the central tungsten concentration and, in many cases, stabilizing the plasma. In order to extend the applicability of central ECRH to a wider range of magnetic field and plasma current additional ECRH schemes with reduced single-pass absorption have been implemented: X3 heating allows us to reduce the magnetic field by 30%, such that the first H-modes with an ITER-like value of the safety factor of q95 = 3 could be run in the tungsten-coated device. O2 heating increases the cutoff density by a factor of 2 allowing higher currents and triangularities to be addressed. For both schemes, scenarios have been developed to cope with the associated reduced absorption. In the case of central X3 heating, the X2 resonance lies close to the pedestal top at the high-field side of the plasma, serving as a beam dump. For O2, holographic mirrors have been developed which guarantee a second pass through the plasma centre. The beam position on these reflectors is controlled by fast thermocouples. Stray-radiation protection has been implemented using sniffer probes.

A revised model for Jeffrey nanofluid subject to convective condition and heat generation/absorption

PubMed Central

Hayat, Tasawar; Aziz, Arsalan; Muhammad, Taseer; Alsaedi, Ahmed

2017-01-01

Here magnetohydrodynamic (MHD) boundary layer flow of Jeffrey nanofluid by a nonlinear stretching surface is addressed. Heat generation/absorption and convective surface condition effects are considered. Novel features of Brownian motion and thermophoresis are present. A non-uniform applied magnetic field is employed. Boundary layer and small magnetic Reynolds number assumptions are employed in the formulation. A newly developed condition with zero nanoparticles mass flux is imposed. The resulting nonlinear systems are solved. Convergence domains are explicitly identified. Graphs are analyzed for the outcome of sundry variables. Further local Nusselt number is computed and discussed. It is observed that the effects of Hartman number on the temperature and concentration distributions are qualitatively similar. Both temperature and concentration distributions are enhanced for larger Hartman number. PMID:28231298

Functional properties of protein isolates extracted from stabilized rice bran by microwave, dry heat, and parboiling.

PubMed

Khan, Saima Hafeez; Butt, Masood Sadiq; Sharif, Mian Kamran; Sameen, Ayesha; Mumtaz, Semee; Sultan, Muhammad Tauseef

2011-03-23

Protein isolates extracted from differently stabilized rice bran were analyzed to work out the food use potential. Bulk density remained higher for isolates obtained from heat stabilized bran, the treatments were found to have positive impact on the oil absorption properties, while the water absorption was slightly impaired owing to some possible configurational changes. Surface hydrophobicity and emulsion properties were improved with bran stabilization. Isolates exhibited better foaming properties owing to the flexible nature of protein molecules, with less intensive disulfide bonding, that were slightly affected by the stabilization treatment. Nitrogen solubility index followed a curved pattern with the least value near isoelectric point that showed an increasing trend toward basic pH, and parboiled protein isolates exhibited better gelling properties among the isolates.

Theoretical studies of the physics of the solar atmosphere

NASA Technical Reports Server (NTRS)

Hollweg, Joseph V.

1992-01-01

Significant advances in our theoretical basis for understanding several physical processes related to dynamical phenomena on the sun were achieved. We have advanced a new model for spicules and fibrils. We have provided a simple physical view of resonance absorption of MHD surface waves; this allowed an approximate mathematical procedure for obtaining a wealth of new analytical results which we applied to coronal heating and p-mode absorption at magnetic regions. We provided the first comprehensive models for the heating and acceleration of the transition region, corona, and solar wind. We provided a new view of viscosity under coronal conditions. We provided new insights into Alfven wave propagation in the solar atmosphere. And recently we have begun work in a new direction: parametric instabilities of Alfven waves.

Heat Treatment of Closed-Cell A356 + 4 wt.%Cu + 2 wt.%Ca Foam and Its Effect on the Foam Mechanical Behavior

NASA Astrophysics Data System (ADS)

Mirbagheri, S. M. H.; Vali, H.; Soltani, H.

2017-01-01

In this investigation, aluminum-silicon alloy foam is developed by adding certain amounts of copper and calcium elements in A356 alloy. Addition of 4 wt.%Cu + 2 wt.%Ca to the melt changed bubbles morphology from ellipsoid to spherical by decreasing Reynolds number and increasing Bond number. Compression behavior and energy absorption of the foams are assessed before and after aging. Solid solution treatment and aging lead to the best mechanical properties with 170% enhancement in yield strength and 185% improvement in energy absorption capacity as compared to non-heat-treated foams. The metallographic observations showed that bubbles geometry and structure in the A356 + 4wt.% Cu + 2 wt.%Ca foam are more homogeneous than the A356 foam.

Electron Bernstein waves in spherical torus plasmas

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

Saveliev, A. N.

2006-11-30

Propagation and absorption of the electron Bernstein waves (EBWs) in spherical tokamaks (STs) have been intensively discussed in recent years because the EBWs coupled with an externally launched electromagnetic beam seem to be the only opportunity for microwave plasma heating and current drive in the electron cyclotron (EC) frequency range in the STs. The whole problem of the electron Bernstein heating and current drive (EBWHCD) in spherical plasmas is naturally divided into three major parts: coupling of incident electromagnetic waves (EMWs) to the EBWs near the upper hybrid resonance (UHR) surface, propagation and absorption of the EBWs in the plasmamore » interior and generation of noninductive current driven by the EBWs. The present paper is a brief survey of the most important theoretical and numerical results on the issue of EBWs.« less

Fiber optic gas sensor

NASA Technical Reports Server (NTRS)

Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

2010-01-01

A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

Numerical Investigation of the Effect of Some Parameters on Temperature Field and Kerf Width in Laser Cutting Process

NASA Astrophysics Data System (ADS)

Kheloufi, Karim; Amara, El Hachemi

A transient numerical model is developed to study the temperature field and the kerf shape during laser cutting process. The Fresnel absorption model is used to handle the absorption of the incident wave by the surface of the liquid metal and the enthalpy-porosity technique is employed to account for the latent heat during melting and solidification of the material. The VOF method is used to track the evolution of the shape of the kerf. Physical phenomena occurring at the liquid/gas interface, including friction force and pressure force exerted by the gas jet and the heat absorbed by the surface, are incorporated into the governing equations as source terms. Temperature and velocity distribution, and kerf shape are investigated.

A mechanism for deep chromospheric heating during solar flares

NASA Technical Reports Server (NTRS)

Machado, M. E.; Emslie, A. G.; Mauas, P. J.

1986-01-01

The role of the negative hydrogen ion, H(-), in the energy balance of the deep solar chromosphere is reexamined and it is found, in contrast with earlier authors, that H(-) is a source of heating at these levels. The response of this region to an ionizing flux of flare-associated UV radiation (1500 to 1900 A) is then addressed: it is found that the excess ionization of Si to Si(+) increases the local electron number density considerably, since most species are largely neutral at deep chromospheric levels. This in turn increases the electron-hydrogen atom association rate, the H(-) abundance, and the rate of absorption of photospheric radiation by this ion. It is found that the excess absorption by this process may lead to a substantial temperature enhancement at temperature minimum levels during flares.

Effects of heat stress on the gene expression of nutrient transporters in the jejunum of broiler chickens ( Gallus gallus domesticus)

NASA Astrophysics Data System (ADS)

Sun, Xiaolei; Zhang, Haichao; Sheikhahmadi, Ardashir; Wang, Yufeng; Jiao, Hongchao; Lin, Hai; Song, Zhigang

2015-02-01

In broiler chickens, heat stress disrupts nutrient digestion and absorption. However, the underlying molecular mechanism is not clearly understood. Hence, to investigate the effects of high ambient temperatures on the expression levels of nutrient transporters in the jejunum of broiler chickens, seventy-two 35-day-old male broiler chickens with similar body weights were randomly allocated into two groups: control (24 ± 1 °C) and heat-stressed (32 ± 1 °C). The chickens in the heat-stressed group were exposed to 10 h of heat daily from 08:00 to 18:00 and then raised at 24 ± 1 °C. The rectal temperature and feed intake of the chickens were recorded daily. After 7 days, nine chickens per group were sacrificed by exsanguination, and the jejunum was collected. The results show that heat exposure significantly decreased the feed intake and increased the rectal temperature of the broiler chickens. The plasma concentrations of uric acid and triglyceride significantly increased and decreased, respectively, in the heat-stressed group. No significant differences in the levels of plasma glucose, total amino acids, and very low-density lipoprotein were observed between the heat-stressed and control groups. However, the plasma concentration of glucose tended to be higher ( P = 0.09) in the heat-stressed group than in the control group. Heat exposure did not significantly affect the mRNA levels of Na+-dependent glucose transporter 1 and amino acid transporters y + LAT1, CAT1, r-BAT, and PePT-1. However, the expression levels of GLUT-2, FABP1, and CD36 were significantly decreased by heat exposure. The results of this study provide new insights into the mechanisms by which heat stress affects nutrient absorption in broiler chickens. Our findings suggest that periodic heat exposure might alter the jejunal glucose and lipid transport rather than amino acid transport. However, intestinal epithelial damage and cell loss should be considered when interpreting the effects of heat stress on the expression of intestinal transporters.

Whistlers, Helicons, Lower Hybrid Waves: the Physics of RF Wave Absorption Without Cyclotron Resonances

NASA Astrophysics Data System (ADS)

Pinsker, R. I.

2014-10-01

In hot magnetized plasmas, two types of linear collisionless absorption processes are used to heat and drive noninductive current: absorption at ion or electron cyclotron resonances and their harmonics, and absorption by Landau damping and the transit-time-magnetic-pumping (TTMP) interactions. This tutorial discusses the latter process, i.e., parallel interactions between rf waves and electrons in which cyclotron resonance is not involved. Electron damping by the parallel interactions can be important in the ICRF, particularly in the higher harmonic region where competing ion cyclotron damping is weak, as well as in the Lower Hybrid Range of Frequencies (LHRF), which is in the neighborhood of the geometric mean of the ion and electron cyclotron frequencies. On the other hand, absorption by parallel processes is not significant in conventional ECRF schemes. Parallel interactions are especially important for the realization of high current drive efficiency with rf waves, and an application of particular recent interest is current drive with the whistler or helicon wave at high to very high (i.e., the LHRF) ion cyclotron harmonics. The scaling of absorption by parallel interactions with wave frequency is examined and the advantages and disadvantages of fast (helicons/whistlers) and slow (lower hybrid) waves in the LHRF in the context of reactor-grade tokamak plasmas are compared. In this frequency range, both wave modes can propagate in a significant fraction of the discharge volume; the ways in which the two waves can interact with each other are considered. The use of parallel interactions to heat and drive current in practice will be illustrated with examples from past experiments; also looking forward, this tutorial will provide an overview of potential applications in tokamak reactors. Supported by the US Department of Energy under DE-FC02-04ER54698.

Atomically designed precursors in optical fiber amplifiers: The thermal stability of the heterobimetallic ErAl3(OPri)12 in a solution-coated silica soot

NASA Astrophysics Data System (ADS)

Engholm, M.; Lashgari, K.; Edvardsson, S.; Westin, G.; Norin, L.

2005-06-01

The thermal stability of the bimetallic alkoxide ErAl3(OPri)12 doped in an unsintered silica (soot) has been investigated. Samples have been heated to different temperatures (up to 1500°C and analyzed by using ultraviolet-visible-near infrared absorption spectroscopy, infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, thermal gravimetric analysis, and powder x-ray diffraction. It is seen that the doped samples heated up to 1000°C show broad glasslike absorption spectra, indicating an amorphous structure, while the high-temperature sample shows an ordered crystallinelike structure with sharp characteristic absorption peaks. X-ray diffraction measurements indicate the formation of an ordered structure at temperatures of 1500°C, revealing a crystal phase of silica and phases of erbium and aluminosilicate. A comparison is also made with a sample doped with aqueous ErCl3 and Al(NO3)3. It is concluded that the local structure of the ErAl3 precursor is not preserved at temperatures above 1000°C. Alternative doping procedures are discussed.

Second harmonic generation of q-Gaussian laser beam in preformed collisional plasma channel with nonlinear absorption

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

Gupta, Naveen, E-mail: naveens222@rediffmail.com; Singh, Arvinder, E-mail: arvinder6@lycos.com; Singh, Navpreet, E-mail: navpreet.nit@gmail.com

2015-11-15

This paper presents a scheme for second harmonic generation of an intense q-Gaussian laser beam in a preformed parabolic plasma channel, where collisional nonlinearity is operative with nonlinear absorption. Due to nonuniform irradiance of intensity along the wavefront of the laser beam, nonuniform Ohmic heating of plasma electrons takes place. Due to this nonuniform heating of plasma, the laser beam gets self-focused and produces strong density gradients in the transverse direction. The generated density gradients excite an electron plasma wave at pump frequency that interacts with the pump beam to produce its second harmonics. The formulation is based on amore » numerical solution of the nonlinear Schrodinger wave equation in WKB approximation followed by moment theory approach. A second order nonlinear differential equation governing the propagation dynamics of the laser beam with distance of propagation has been obtained and is solved numerically by Runge Kutta fourth order technique. The effect of nonlinear absorption on self-focusing of the laser beam and conversion efficiency of its second harmonics has been investigated.« less

Extension of Weighted Sum of Gray Gas Data to Mathematical Simulation of Radiative Heat Transfer in a Boiler with Gas-Soot Media

PubMed Central

Nouri-Borujerdi, Ali; Kazi, Salim Newaz

2014-01-01

In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site. PMID:25143981

Extension of weighted sum of gray gas data to mathematical simulation of radiative heat transfer in a boiler with gas-soot media.

PubMed

Gharehkhani, Samira; Nouri-Borujerdi, Ali; Kazi, Salim Newaz; Yarmand, Hooman

2014-01-01

In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site.

Effect of γ-aminobutyric acid on digestive enzymes, absorption function, and immune function of intestinal mucosa in heat-stressed chicken.

PubMed

Chen, Z; Xie, J; Wang, B; Tang, J

2014-10-01

To explore the effect of dietary γ-aminobutyric acid (GABA) on digestive enzyme activity, absorption function and immune function of intestinal mucosa in heat-stressed Wenchang chicken were studied. One-day-old male Wenchang chickens were randomly divided into a control group (CK), heat stress group (HS), and GABA+HS group. The chickens from the GABA+HS group were administered with 0.2 mL of GABA solution daily. Chickens from HS and GABA+HS groups were subjected to heat stress treatment at 40 ± 0.5°C for 2 h during 1300 to 1500 h every day. Blood was drawn and 0.5 cm-long duodenum, jejunum, and ileum were collected from the chickens on d 3, 5, 7, 9, 12, and 15. Results showed that the activity of Ca²⁺-Mg²⁺-adenosine triphosphatase (ATPase), Na⁺-K⁺-ATPase, maltase, sucrase, and alkaline phosphatase, the contents of secretory IgA, glutathione, and d-xylose, and the number of lymphocytes in HS group were significantly lower than those in the CK group. Among them, some were rescued after the treatment of GABA as the time extension. For maltase, d-xylose, alkaline phosphatase, and Na⁺-K⁺-ATPase, it required 5 to 7 d for achieving the significant effect. For sucrase, 12 d for the alleviation effect was required. In the case of other parameters, no alleviation was observed during the whole period of the study. We have concluded that HS can inhibit the activity of digestive enzymes and reduce absorption and immune functions of intestinal mucosa. γ-Aminobutyric acid can effectively alleviate these inhibitory effects. ©2014 Poultry Science Association Inc.

Air-Conditioning for Electric Vehicles

NASA Technical Reports Server (NTRS)

Popinski, Z.

1984-01-01

Combination of ammonia-absorption refrigerator, roof-mounted solar collectors, and 200 degrees C service electric-vehicle motor provides evaporative space-heating/space cooling system for electric-powered and hybrid fuel/electric vehicles.

Combining IRIS/Hinode Observations and Modeling: a Pathfinder for Coronal Heating

NASA Astrophysics Data System (ADS)

Antolin, P.; Okamoto, J.; De Pontieu, B.

2015-12-01

The combination of imaging and spectroscopic instruments with multiple temperature diagnostics at high spatial, temporal and spectral resolution can allow to recover the 3D plasma flow and thermodynamic evolution associated with specific coronal heating mechanisms. Although very hard considering the complexity of the solar atmosphere, this approach is becoming possible now through combination of instruments such as IRIS and Hinode, and with proper guiding from advanced numerical simulations and forward modeling. In this talk I will review recent examples of this approach, focusing on a particular, recently published, case study, that serves as a pathfinder in the search for the dominant coronal heating mechanism. In this case, resonant absorption, a long hypothesised wave-related energy conversion mechanism is spotted in action for the first time, and is characterised by a peculiar 3D motion of the plasma. With the help of 3D MHD numerical simulations and forward modeling the observational signatures of resonant absorption are characterised, matching very well the observational results. The process through which this mechanism can lead to observed significant heating in the solar corona is further identified: the resonant flow becomes turbulent following dynamic instabilities and heats the plasma. I will show how this resonance + instability process is expected in different scenarios of the solar atmosphere (the corona, prominences and spicules) and can potentially explain several observed features that remain so far unexplained.

Conceptual design of a thermal control system for an inflatable lunar habitat module

NASA Technical Reports Server (NTRS)

Gadkari, Ketan; Goyal, Sanjay K.; Vanniasinkam, Joseph

1991-01-01

NASA is considering the establishment of a manned lunar base within the next few decades. To house and protect the crew from the harsh lunar environment, a habitat is required. A proposed habitat is an spherical, inflatable module. Heat generated in the module must be rejected to maintain a temperature suitable for human habitation. This report presents a conceptual design of a thermal control system for an inflatable lunar module. The design solution includes heat acquisition, heat transport, and heat rejection subsystems. The report discusses alternative designs and design solutions for each of the three subsystems mentioned above. Alternative subsystems for heat acquisition include a single water-loop, a single air-loop, and a double water-loop. The vapor compression cycle, vapor absorption cycle, and metal hydride absorption cycle are the three alternative transport subsystems. Alternative rejection subsystems include flat plate radiators, the liquid droplet radiator, and reflux boiler radiators. Feasibility studies on alternatives of each subsystem showed that the single water-loop, the vapor compression cycle, and the reflux boiler radiator were the most feasible alternatives. The design team combined the three subsystems to come up with an overall system design. Methods of controlling the system to adapt it for varying conditions within the module and in the environment are presented. Finally, the report gives conclusions and recommendations for further study of thermal control systems for lunar applications.

Modelling ultrafast laser ablation

NASA Astrophysics Data System (ADS)

Rethfeld, Baerbel; Ivanov, Dmitriy S.; E Garcia, Martin; Anisimov, Sergei I.

2017-05-01

This review is devoted to the study of ultrafast laser ablation of solids and liquids. The ablation of condensed matter under exposure to subpicosecond laser pulses has a number of peculiar properties which distinguish this process from ablation induced by nanosecond and longer laser pulses. The process of ultrafast ablation includes light absorption by electrons in the skin layer, energy transfer from the skin layer to target interior by nonlinear electronic heat conduction, relaxation of the electron and ion temperatures, ultrafast melting, hydrodynamic expansion of heated matter accompanied by the formation of metastable states and subsequent formation of breaks in condensed matter. In case of ultrashort laser excitation, these processes are temporally separated and can thus be studied separately. As for energy absorption, we consider peculiarities of the case of metal irradiation in contrast to dielectrics and semiconductors. We discuss the energy dissipation processes of electronic thermal wave and lattice heating. Different types of phase transitions after ultrashort laser pulse irradiation as melting, vaporization or transitions to warm dense matter are discussed. Also nonthermal phase transitions, directly caused by the electronic excitation before considerable lattice heating, are considered. The final material removal occurs from the physical point of view as expansion of heated matter; here we discuss approaches of hydrodynamics, as well as molecular dynamic simulations directly following the atomic movements. Hybrid approaches tracing the dynamics of excited electrons, energy dissipation and structural dynamics in a combined simulation are reviewed as well.

Solar and chemical reaction-induced heating in the terrestrial mesosphere and lower thermosphere

NASA Technical Reports Server (NTRS)

Mlynczak, Martin G.

1992-01-01

Airglow and chemical processes in the terrestrial mesosphere and lower thermosphere are reviewed, and initial parameterizations of the processes applicable to multidimensional models are presented. The basic processes by which absorbed solar energy participates in middle atmosphere energetics for absorption events in which photolysis occurs are illustrated. An approach that permits the heating processes to be incorporated in numerical models is presented.

49 CFR 173.225 - Packaging requirements and other provisions for organic peroxides.

Code of Federal Regulations, 2010 CFR

2010-10-01

... insulation (W·m−2·K−1); where K = heat conductivity of insulation layer (W·m−1·K−1), and L = thickness of... complete fire engulfment as calculated by the following formula: ER20DE04.002 Where: q = heat absorption (W) A = wetted area (m2) F = insulation factor (−) (B) Insulation factor (F) in the formula in paragraph...

49 CFR 173.225 - Packaging requirements and other provisions for organic peroxides.

Code of Federal Regulations, 2011 CFR

2011-10-01

... insulation (W·m−2·K−1); where K = heat conductivity of insulation layer (W·m−1·K−1), and L = thickness of... complete fire engulfment as calculated by the following formula: ER20DE04.002 Where: q = heat absorption (W) A = wetted area (m2) F = insulation factor (−) (B) Insulation factor (F) in the formula in paragraph...

Application of solar energy to air conditioning systems

NASA Technical Reports Server (NTRS)

Nash, J. M.; Harstad, A. J.

1976-01-01

The results of a survey of solar energy system applications of air conditioning are summarized. Techniques discussed are both solar powered (absorption cycle and the heat engine/Rankine cycle) and solar related (heat pump). Brief descriptions of the physical implications of various air conditioning techniques, discussions of status, proposed technological improvements, methods of utilization and simulation models are presented, along with an extensive bibliography of related literature.

Heat pipe temperature control utilizing a soluble gas absorption reservior

NASA Technical Reports Server (NTRS)

Saaski, E. W.

1976-01-01

A new gas-controlled heat pipe design is described which uses a liquid matrix reservior, or sponge, to replace the standard gas reservior. Reservior volume may be reduced by a factor of five to ten for certain gas-liquid combinations, while retaining the same level of temperature control. Experiments with ammonia, butane, and carbon dioxide control gases with methanol working fluid are discussed.

Ride-along data LOS 130, 170 & LO330 shots z3139, 3140 and 3141

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

Loisel, Guillaume Pascal

Each instrument records the x-ray emission from the Z-pinch dynamic hohlraum (ZPDH); LOS 130 TIXTLs instruments record the absorption of the pinch backlighter through an expanding NaF/Mg foil; LOS 170 MLM instruments record monochromatic images at 276 and 528 eV energies near and before ZPDH stagnation time; LOS 330 TREX 6A & B: recoded time resolved absorption spectra from a radiatively heated Ne gas.

Wavelength-selective mid-infrared metamaterial absorbers with multiple tungsten cross resonators.

PubMed

Li, Zhigang; Stan, Liliana; Czaplewski, David A; Yang, Xiaodong; Gao, Jie

2018-03-05

Wavelength-selective metamaterial absorbers in the mid-infrared range are demonstrated by using multiple tungsten cross resonators. By adjusting the geometrical parameters of cross resonators in single-sized unit cells, near-perfect absorption with single absorption peak tunable from 3.5 µm to 5.5 µm is realized. The combination of two, three, or four cross resonators of different sizes in one unit cell enables broadband near-perfect absorption at mid-infrared range. The obtained absorption spectra exhibit omnidirectionality and weak dependence on incident polarization. The underlying mechanism of near-perfect absorption with cross resonators is further explained by the optical mode analysis, dispersion relation and equivalent RLC circuit model. Moreover, thermal analysis is performed to study the heat generation and temperature increase in the cross resonator absorbers, while the energy conversion efficiency is calculated for the thermophotovoltaic system made of the cross resonator thermal emitters and low-bandgap semiconductors.

Experimental research in the phase change materials based on paraffin and expanded perlite

NASA Astrophysics Data System (ADS)

Jiesheng, Liu; Faping, Li; Xiaoqiang, Gong; Rongtang, Zhang

2018-06-01

In this study, paraffin (PA)/expanded perlite (EP) form-stable phase change material (PCM) was first fabricated using the direct impregnation method without vacuum treatment. Absorptive capacity results showed that the PA/EP composite can obtain good absorptive capacity with the temperature 80 °C and the time 2 h. Compared with the water absorption of EP, the decrease in the water absorption of PA/EP form-stable proved that the absorption of PA into porous EP has been carried out successfully. Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) results show that paraffin can be well impregnated into EP pores and has good compatibility with it. Differential scanning calorimetry (DSC) results reveal that paraffin/EP composite PCM has melting temperature and latent heat of 53.6 °C and 91.3 J/g, respectively. The durability cycles results suggest that form-stable PA/EP PCM shows good durability.

Regeneration of 2-amino-2-methyl-1-propanol used for carbon dioxide absorption.

PubMed

Zhang, Pei; Shi, Yao; Wei, Jianwen; Zhao, Wei; Ye, Qing

2008-01-01

To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1-propranol (AMP) was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regenerationruns descended from 98.3% to 94.0%. A number of heat-stable salts (HSS) could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine (MEA), diethanolamine (DEA), diethylenetriamine (DETA), and N-methyldiethanolamine (MDEA).

O2-O2 and O2-N2 collision-induced absorption mechanisms unravelled

NASA Astrophysics Data System (ADS)

Karman, Tijs; Koenis, Mark A. J.; Banerjee, Agniva; Parker, David H.; Gordon, Iouli E.; van der Avoird, Ad; van der Zande, Wim J.; Groenenboom, Gerrit C.

2018-05-01

Collision-induced absorption is the phenomenon in which interactions between colliding molecules lead to absorption of light, even for transitions that are forbidden for the isolated molecules. Collision-induced absorption contributes to the atmospheric heat balance and is important for the electronic excitations of O2 that are used for remote sensing. Here, we present a theoretical study of five vibronic transitions in O2-O2 and O2-N2, using analytical models and numerical quantum scattering calculations. We unambiguously identify the underlying absorption mechanism, which is shown to depend explicitly on the collision partner—contrary to textbook knowledge. This explains experimentally observed qualitative differences between O2-O2 and O2-N2 collisions in the overall intensity, line shape and vibrational dependence of the absorption spectrum. It is shown that these results can be used to discriminate between conflicting experimental data and even to identify unphysical results, thus impacting future experimental studies and atmospheric applications.

Re-Evaluation of Dust Radiative Forcing Using Remote Measurements of Dust Absorption

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Tanre, Didier; Karnieli, Arnon; Remer, Lorraine A.

1998-01-01

Spectral remote observations of dust properties from space and from the ground creates a powerful tool for determination of dust absorption of solar radiation with an unprecedented accuracy. Absorption is a key component in understanding dust impact on climate. We use Landsat spaceborne measurements at 0.47 to 2.2 microns over Senegal with ground based sunphotometers to find that Saharan dust absorption of solar radiation is two to four times smaller than in models. Though dust absorbs in the blue, almost no absorption was found for wavelengths greater 0.6 microns. The new finding increases by 50% recent estimated solar radiative forcing by dust and decreases the estimated dust heating of the lower troposphere. Dust transported from Asia shows slightly higher absorption probably due to the presence of black carbon from populated regions. Large scale application of this method to satellite data from the Earth Observing System can reduce significantly the uncertainty in the dust radiative effects.

Analysis of Aerospike Plume Induced Base-Heating Environment

NASA Technical Reports Server (NTRS)

Wang, Ten-See

1998-01-01

Computational analysis is conducted to study the effect of an aerospike engine plume on X-33 base-heating environment during ascent flight. To properly account for the effect of forebody and aftbody flowfield such as shocks and to allow for potential plume-induced flow-separation, thermo-flowfield of trajectory points is computed. The computational methodology is based on a three-dimensional finite-difference, viscous flow, chemically reacting, pressure-base computational fluid dynamics formulation, and a three-dimensional, finite-volume, spectral-line based weighted-sum-of-gray-gases radiation absorption model computational heat transfer formulation. The predicted convective and radiative base-heat fluxes are presented.

System effects of primary energy reduction connected with operation of the CHP plants

NASA Astrophysics Data System (ADS)

Ziębik, Andrzej; Gładysz, Paweł

2017-06-01

The paper is devoted to explication of one of the advantages of heat and electricity cogeneration, rarely considered in technical literature. Usually attention is paid to the fact that heat losses of the heat distribution network are less severe in the case of cogeneration of heat in comparison with its separate production. But this conclusion is also true in other cases when the internal consumption of heat is significant. In this paper it has been proved in the case of two examples concerning trigeneration technology with an absorption chiller cooperating with a combined heat and power (CHP) plant and CHP plant integrated with amine post-combustion CO2 processing unit. In both considered cases it might be said that thanks to cogeneration we have to do with less severe consequences of significant demand of heat for internal purposes.

Laser ablation based fuel ignition

DOEpatents

Early, J.W.; Lester, C.S.

1998-06-23

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

Laser ablation based fuel ignition

DOEpatents

Early, James W.; Lester, Charles S.

1998-01-01

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

NASA Technical Reports Server (NTRS)

1981-01-01

The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

Experimental investigation and model verification for a GAX absorber

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

Palmer, S.C.; Christensen, R.N.

1996-12-31

In the ammonia-water generator-absorber heat exchange (GAX) absorption heat pump, the heat and mass transfer processes which occur between the generator and absorber are the most crucial in assuring that the heat pump will achieve COPs competitive with those of current technologies. In this study, a model is developed for the heat and mass transfer processes that occur in a counter-current vertical fluted tube absorber (VFTA) with inserts. Correlations for heat and mass transfer in annuli are used to model the processes in the VTA. Experimental data is used to validate the model for three different insert geometries. Comparison ofmore » model results with experimental data provides insight into model corrections necessary to bring the model into agreement with the physical phenomena observed in the laboratory.« less

High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8 μm

NASA Astrophysics Data System (ADS)

Sajid, M. B.; Javed, T.; Farooq, A.

2015-04-01

The mid-infrared wavelength region near 8 μm contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the ν4 band of methane and the ν4+ν5 band of acetylene is reported for interference-free, time-resolved measurements under combustion-relevant conditions. A detailed line-selection procedure was used to identify optimum transitions. Methane and acetylene were measured at the line centers of Q12 (1303.5 cm-1) and P23 (1275.5 cm-1) transitions, respectively. High-temperature absorption cross sections of methane and acetylene were measured at peaks (on-line) and valleys (off-line) of the selected absorption transitions. The differential absorption strategy was employed to eliminate interference absorption from large hydrocarbons. Experiments were performed behind reflected shock waves over a temperature range of 1200-2200 K, between pressures of 1-4 atm. The diagnostics were then applied to measure the respective species time-history profiles during the shock-heated pyrolysis of n-pentane.

Surface tension mediated conversion of light to work

DOEpatents

Okawa, David; Pastine, Stefan J; Zettl, Alexander K; Frechet, Jean M. J

2014-12-02

Disclosed are a method and apparatus for converting light energy to mechanical energy by modification of surface tension on a supporting fluid. The apparatus comprises an object which may be formed as a composite object comprising a support matrix and a highly light absorptive material. The support matrix may comprise a silicon polymer. The highly light absorptive material may comprise vertically aligned carbon nanotubes (VANTs) embedded in the support matrix. The composite object is supported on a fluid. By exposing the highly light absorptive material to light, heat is generated, which changes the surface tension of the composite object, causing it to move physically within the fluid.

LASER PLASMA AND LASER APPLICATIONS: Plasma transparency in laser absorption waves in metal capillaries

NASA Astrophysics Data System (ADS)

Anisimov, V. N.; Kozolupenko, A. P.; Sebrant, A. Yu

1988-12-01

An experimental investigation was made of the plasma transparency to heating radiation in capillaries when absorption waves propagated in these capillaries as a result of interaction with a CO2 laser pulse of 5-μs duration. When the length of the capillary was in excess of 20 mm, total absorption of the radiation by the plasma was observed at air pressures of 1-100 kPa. When the capillary length was 12 mm, a partial recovery of the transparency took place. A comparison was made with the dynamics and recovery of the plasma transparency when breakdown of air took place near the free surface.

Tunable infrared laser detection of pyrolysis products of explosives in soils

NASA Astrophysics Data System (ADS)

Wormhoudt, J.; Shorter, J. H.; McManus, J. B.; Kebabian, P. L.; Zahniser, M. S.; Kolb, Charles E.; Davis, W. M.; Cespedes, E. R.

1996-07-01

A research program involving two applications of tunable infrared laser differential absorption spectroscopy (TILDAS) with multipass, long-path absorption cells to the detection of explosives contamination in soils is reported. In the first application, sensitive, specific real-time species concentration measurements by TILDAS have led to new understanding of the processes involved in explosives detection by the heating of contaminated soils and the quantification of the resulting pyrolysis gases. In the second, we present results of our calculations of the properties of astigmatic off-axis resonator absorption cells, which show that useful TILDAS path lengths can be achieved inside a cone penetrometer probe.

Modeling of a solar-assisted hybrid absorption/desiccant system for applications in Puerto Rico and the Caribbean

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

Hernandez, H.R.; Gonzalez, J.E.; Khan, A.Y.

1996-11-01

This study is concerned with the feasibility of different arrangements of solar-assisted air conditioning systems for applications in Puerto Rico. The thermodynamic performance of an absorption system alone and coupled to a liquid or a solid desiccant dehumidification system was investigated under variable cooling load conditions. The dynamic modeling was based on heat and mass balances for the systems components. Simulations for climatic conditions in Puerto Rico show that average solar fractions of more than 85% can be achieved with both the absorption system and the hybrid systems for medium size cooling loads. Results indicate that higher coefficients of performancemore » are obtained when the solar assisted absorption system is not coupled to a desiccant dehumidification system.« less

Aerosol Absorption in the Atmosphere: Perspectives from Global Model, Ground-Based Measurements, and Field Observations

NASA Technical Reports Server (NTRS)

Chin, Mian; Dubovik, Oleg; Holben, Brent; Torres, Omar; Anderson, Tad; Quinn, Patricia; Ginoux, Paul

2004-01-01

Aerosol absorption in the atmosphere poses a major uncertainty in assessing the aerosol climate effects. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, and our limited knowledge of aerosol mixing state and optical properties. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt. We compare the model calculated total aerosol optical thickness, extinction, and absorption with those quantities from the ground-based sun photometer measurements from AERONET, satellite retrievals from the TOMS instrument, and field observations from ACE-Asia. We will examine the most sensitive factors in determining the aerosol absorption. and the consequences of assessing the aerosol radiative forcing and atmospheric heating associated with those factors.

Aerosol Absorption in the Atmosphere: Perspectives from Global Model, Ground-Based Measurements, and Field Observations

NASA Technical Reports Server (NTRS)

Chin, Mian; Dubovik, Oleg; Holben, Brent; Anderson, Tad; Quinn, Patricia; Duncan, Bryan; Ginoux, Paul

2003-01-01

Aerosol absorption in the atmosphere poses a major uncertainty in assessing the aerosol climate effects. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, and our limited knowledge of aerosol mixing state and optical properties. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt. We compare the model calculated total aerosol optical thickness, extinction, and absorption with those quantities from the ground-based sun photometer measurements from AERONET at several different wavelengths and the field observations from ACE-Asia. We will examine what are the most sensitive factors in determining the aerosol absorption, and the consequences of assessing the aerosol radiative forcing and atmospheric heating associated with those factors.

Aerosol Absorption in the Atmosphere: Perspectives from Global Model, Ground-Based Measurements, and Field Observations

NASA Technical Reports Server (NTRS)

Chin, Main; Dubovik, Oleg; Holben, Brent; Anderson, Tad; Quinn, Patricia; Duncan, Bryan; Ginoux, Paul

2004-01-01

Aerosol absorption in the atmosphere poses a major uncertainty in assessing the aerosol climate effects. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, and our limited knowledge of aerosol mixing state and optical properties. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt. We compare the model calculated total aerosol optical thickness, extinction, and absorption with those quantities from the ground-based sun photometer measurements from AERONET at several different wavelengths and the field observations from ACE-Asia. We will examine the most sensitive factors in determining the aerosol absorption, and the consequences of assessing the aerosol radiative forcing and atmospheric heating associated with those factors.

Radiation effects on beta /10.6/ of pure and europium doped KCl

NASA Technical Reports Server (NTRS)

Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

1975-01-01

Changes in the optical absorption coefficient as the result of X-ray and electron bombardment of pure monocrystalline and polycrystalline KCl and of divalent europium doped polycrystalline KCl were determined. A constant heat flow calorimetric method was used to measure the optical absorption coefficients. Both 300 kV X-ray irradiation and 2 MeV electron irradiation produced increases in the optical absorption coefficient at room temperature. X-ray irradiation produced more significant changes in pure monocrystalline KCl than equivalent amounts of electron irradiation. Electron irradiation of pure and Eu-doped polycrystalline KCl produced increases in the absorption by as much as a factor of 20 over untreated material. Bleaching of the electron-irradiated doped KCl with 649 millimicron light produced a further increase.

Apparatus Notes

ERIC Educational Resources Information Center

Eaton, Bruce G., Ed.

1976-01-01

Includes five brief articles on: solar-heating demonstration equipment, mercury or sodium vapor lamp spectroscopy, an apparatus for simulating variable stars, a voltage-to-frequency converter, and an introductory absorption experiment for low-energy beta particles. (MLH)

Threshold heating temperature for magnetic hyperthermia: Controlling the heat exchange with the blocking temperature of magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Pimentel, B.; Caraballo-Vivas, R. J.; Checca, N. R.; Zverev, V. I.; Salakhova, R. T.; Makarova, L. A.; Pyatakov, A. P.; Perov, N. S.; Tishin, A. M.; Shtil, A. A.; Rossi, A. L.; Reis, M. S.

2018-04-01

La0.75Sr0.25MnO3 nanoparticles with average diameter close to 20.9 nm were synthesized using a sol-gel method. Measurements showed that the heating process stops at the blocking temperaturesignificantly below the Curie temperature. Measurements of Specific Absorption Rate (SAR) as a function of AC magnetic field revealed a superquadratic power law, indicating that, in addition to usual Néel and Brown relaxation, the hysteresis also plays an important role in the mechanism of heating. The ability to control the threshold heating temperature, a low remanent magnetization and a low field needed to achieve the magnetic saturation are the advantages of this material for therapeutic magnetic hyperthermia.

During air cool process aerosol absorption detection with photothermal interferometry

NASA Astrophysics Data System (ADS)

Li, Baosheng; Xu, Limei; Huang, Junling; Ma, Fei; Wang, Yicheng; Li, Zhengqiang

2014-11-01

This paper studies the basic principle of laser photothermal interferometry method of aerosol particles absorption coefficient. The photothermal interferometry method with higher accuracy and lower uncertainty can directly measure the absorption coefficient of atmospheric aerosols and not be affected by scattered light. With Jones matrix expression, the math expression of a special polarization interferometer is described. This paper using folded Jamin interferometer, which overcomes the influence of vibration on measuring system. Interference come from light polarization beam with two orthogonal and then combine to one beam, finally aerosol absorption induced refractive index changes can be gotten with four beam of phase orthogonal light. These kinds of styles really improve the stability of system and resolution of the system. Four-channel detections interact with interference fringes, to reduce the light intensity `zero drift' effect on the system. In the laboratory, this device typical aerosol absorption index, it shows that the result completely agrees with actual value. After heated by laser, cool process of air also show the process of aerosol absorption. This kind of instrument will be used to monitor ambient aerosol absorption and suspended particulate matter chemical component. Keywords: Aerosol absorption coefficient; Photothermal interferometry; Suspended particulate matter.

Gas adsorption/absorption heat switch, phase 1

NASA Technical Reports Server (NTRS)

Chan, C. K.

1987-01-01

The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

[The Research for Trace Ammonia Escape Monitoring System Based on Tunable Diode Laser Absorption Spectroscopy].

PubMed

Zhang, Li-fang; Wang, Fei; Yu, Li-bin; Yan, Jian-hua; Cen, Ke-fa

2015-06-01

In order to on-line measure the trace ammonia slip of the commercial power plant in the future, this research seeks to measure the trace ammonia by using tunable diode laser absorption spectroscopy under ambient temperature and pressure, and at different temperatures, and the measuring temperature is about 650 K in the power plant. In recent years lasers have become commercially available in the near-infrared where the transitions are much stronger, and ammonia's spectroscopy is pretty complicated and the overlapping lines are difficult to resolve. A group of ammonia transitions near 4 433.5 cm(-1) in the v2 +v3 combination band have been thoroughly selected for detecting lower concentration by analyzing its absorption characteristic and considering other absorption interference in combustion gases where H2O and CO2 mole fraction are very large. To illustrate the potential for NH3 concentration measurements, predictions for NH3, H2O and CO2 are simultaneously simulated, NH3 absorption lines near 4 433.5 cm(-1) wavelength meet weaker H2O absorption than the commercial NH3 lines, and there is almost no CO2 absorption, all the parameters are based on the HITRAN database, and an improved detection limit was obtained for interference-free NH3 monitoring, this 2.25 μm band has line strengths several times larger than absorption lines in the 1.53 μm band which was often used by NH3 sensors for emission monitoring and analyzing. The measurement system was developed with a new Herriott cell and a heated gas cell realizing fast absorption measurements of high resolution, and combined with direct absorption and wavelenguh modulation based on tunable diode laser absorption spectroscopy at different temperatures. The lorentzian line shape is dominant at ambient temperature and pressure, and the estimated detectivity is approximately 0.225 x 10(-6) (SNR = 1) for the directed absorption spectroscopy, assuming a noise-equivalent absorbance of 1 x 10(-4). The heated cell experiments with controlled the temperature were performed to validate the sensing strategy. Here the Wavelength Modulation Spectroscopy (WMS) strategy was usually used to measure lower gas concentration for high noise immunity to the non-absorption transmission losses. The great agreement 2f signal with the calibrated concentration is within the uncertainty at different temperatures by using simple digital signal processing such as multiple averages, wavelet analysis and so on. The denoise processing has a great advantage in application and implementation over other noise suppression techniques. The result provided a good basis for trace ammonia escape detection based on tunable diode laser absorption spectroscopy.

Nanoparticle-enhanced x-ray therapy for cancer

NASA Astrophysics Data System (ADS)

Letfullin, Renat R.; Rice, Colin E. W.; George, Thomas F.

2016-03-01

Photothermal therapies of nanophotohyperthermia and nanophotothermolysis utilize the light absorptive properties of nanoparticles to create heat and free radicals in a small localized region. Conjugating nanoparticles with various biomolecules allows for targeted delivery to specific tissues or even specific cells, cancerous cells being of particular interest. Previous studies have investigated nanoparticles at visible and infrared wavelengths where surface plasmon resonance leads to unique absorption characteristics. However, issues such as poor penetration depth of the visible light through biological tissues limits the effectiveness of delivery by noninvasive means. In other news, various nanoparticles have been investigated as contrast agents for traditional X-ray procedures, utilizing the strong absorption characteristics of the nanoparticles to enhance contrast of the detected X-ray image. Using X-rays to power photothermal therapies has three main advantages over visiblespectra wavelengths: the high penetration depth of X-rays through biological media makes noninvasive treatments very feasible; the high energy of individual photons means nanoparticles can be heated to desired temperatures with lower beam intensities, or activated to produce the free radicals; and X-ray sources are already common throughout the medical industry, making future implementation on existing equipment possible. This paper uses Lorenz-Mie theory to investigate the light absorption properties of various size gold nanoparticles over photon energies in the 1-100 keV range. These absorption values are then plugged into a thermal model to determine the temperatures reached by the nanoparticles for X-ray exposures of differing time and intensity. The results of these simulations are discussed in relation to the effective implementation of nanophotohyperthermia and nanophotothermolysis treatments.

Optics-based approach to thermal management of photovoltaics: Selective-spectral and radiative cooling

DOE PAGES

Sun, Xingshu; Silverman, Timothy J.; Zhou, Zhiguang; ...

2017-01-20

For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 °C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of photovoltaic (PV) modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of themore » solar module to eliminate parasitic absorption (selective-spectral cooling) and enhance thermal emission (radiative cooling). Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool one-sun terrestrial solar modules up to 10 °C. As a result, this self-cooling would substantially extend the lifetime for solar modules, with corresponding increase in energy yields and reduced levelized cost of electricity.« less

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

NASA Technical Reports Server (NTRS)

Faghri, Amir; Swanson, Theodore D.

1989-01-01

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

Modeling of Ti-W Solidification Microstructures Under Additive Manufacturing Conditions

NASA Astrophysics Data System (ADS)

Rolchigo, Matthew R.; Mendoza, Michael Y.; Samimi, Peyman; Brice, David A.; Martin, Brian; Collins, Peter C.; LeSar, Richard

2017-07-01

Additive manufacturing (AM) processes have many benefits for the fabrication of alloy parts, including the potential for greater microstructural control and targeted properties than traditional metallurgy processes. To accelerate utilization of this process to produce such parts, an effective computational modeling approach to identify the relationships between material and process parameters, microstructure, and part properties is essential. Development of such a model requires accounting for the many factors in play during this process, including laser absorption, material addition and melting, fluid flow, various modes of heat transport, and solidification. In this paper, we start with a more modest goal, to create a multiscale model for a specific AM process, Laser Engineered Net Shaping (LENS™), which couples a continuum-level description of a simplified beam melting problem (coupling heat absorption, heat transport, and fluid flow) with a Lattice Boltzmann-cellular automata (LB-CA) microscale model of combined fluid flow, solute transport, and solidification. We apply this model to a binary Ti-5.5 wt pct W alloy and compare calculated quantities, such as dendrite arm spacing, with experimental results reported in a companion paper.

On the reliable measurement of specific absorption rates and intrinsic loss parameters in magnetic hyperthermia materials

NASA Astrophysics Data System (ADS)

Wildeboer, R. R.; Southern, P.; Pankhurst, Q. A.

2014-12-01

In the clinical application of magnetic hyperthermia, the heat generated by magnetic nanoparticles in an alternating magnetic field is used as a cancer treatment. The heating ability of the particles is quantified by the specific absorption rate (SAR), an extrinsic parameter based on the clinical response characteristic of power delivered per unit mass, and by the intrinsic loss parameter (ILP), an intrinsic parameter based on the heating capacity of the material. Even though both the SAR and ILP are widely used as comparative design parameters, they are almost always measured in non-adiabatic systems that make accurate measurements difficult. We present here the results of a systematic review of measurement methods for both SAR and ILP, leading to recommendations for a standardised, simple and reliable method for measurements using non-adiabatic systems. In a representative survey of 50 retrieved datasets taken from published papers, the derived SAR or ILP was found to be more than 5% overestimated in 24% of cases and more than 5% underestimated in 52% of cases.

Thermoeconomic analysis of an integrated multi-effect desalination thermal vapor compression (MED-TVC) system with a trigeneration system using triple-pressure HRSG

NASA Astrophysics Data System (ADS)

Ghaebi, Hadi; Abbaspour, Ghader

2018-05-01

In this research, thermoeconomic analysis of a multi-effect desalination thermal vapor compression (MED-TVC) system integrated with a trigeneration system with a gas turbine prime mover is carried out. The integrated system comprises of a compressor, a combustion chamber, a gas turbine, a triple-pressure (low, medium and high pressures) heat recovery steam generator (HRSG) system, an absorption chiller cycle (ACC), and a multi-effect desalination (MED) system. Low pressure steam produced in the HRSG is used to drive absorption chiller cycle, medium pressure is used in desalination system and high pressure superheated steam is used for heating purposes. For thermodynamic and thermoeconomic analysis of the proposed integrated system, Engineering Equation Solver (EES) is used by employing mass, energy, exergy, and cost balance equations for each component of system. The results of the modeling showed that with the new design, the exergy efficiency in the base design will increase to 57.5%. In addition, thermoeconomic analysis revealed that the net power, heating, fresh water and cooling have the highest production cost, respectively.

Optical and structural behaviors of crosslinked polyvinyl alcohol thin films

NASA Astrophysics Data System (ADS)

Pandit, Subhankar; Kundu, Sarathi

2018-04-01

Polyvinyl Alcohol (PVA) has excellent properties like uniaxial tensile stress, chemical resistance, biocompatibility, etc. The properties of PVA further can be tuned by crosslinking process. In this work, a simple heat treatment method is used to find out the optimum crosslinking of PVA and the corresponding structural and optical responses are explored. The PVA crosslinking is done by exposing the films at different temperatures and time intervals. The optical property of pure and heat treated PVA films are investigated by UV-Vis absorption and photoluminescence emission spectroscopy and structural modifications are studied by Fourier Transform Infrared Spectroscopy (FTIR). The absorption peaks of pure PVA are observed at ≈ 280 and 335 nm and the corresponding emission is observed at ≈ 424 nm. The pure PVA showed modified optical behaviors after the heat treatment. In addition, dipping the PVA films in hot water (85°C) for nearly 20 minutes also show impact on both structural and optical properties. From FTIR spectroscopy, the changes in vibrational band positions confirm the structural modifications of PVA films.

Optical and heat transfer performance of a novel non-imaging concentrator

NASA Astrophysics Data System (ADS)

Sellami, Nazmi; Meng, Xian-long; Xia, Xin-Lin; Knox, Andrew R.; Mallick, Tapas K.

2015-09-01

In this study, the Crossed Compound Parabolic Concentrator CCPC is modified to demonstrate for the first time a new generation of solar concentrators working simultaneously as an electricity generator and thermal collector. It is designed to have two complementary surfaces, one reflective and one absorptive, and is called an absorptive/reflective CCPC (AR-CCPC). Usually, the height of the CCPC is truncated with a minor sacrifice of the geometric concentration. These truncated surfaces rather than being eliminated are instead replaced with absorbent surfaces to collect heat from solar radiation. The optical, thermal and total efficiency of the AR-CCPC was simulated and compared for different geometric concentration ratios varying from 3.6x to 4x. It was found that the combined electrical and thermal efficiency of the AR-CCPC 3.6x/4x remains constant and high all day long and the overall efficiency reach up to 94%. In addition, the temperature distributions of AR-CCPC surfaces and the assembled solar cell were simulated based on those heat flux boundary conditions. It shows that the adding of thermal absorbent surface can apparently increase the wall temperature.

Polarization effects associated with thermal processing of HY-80 structural steel using high-power laser diode array

NASA Astrophysics Data System (ADS)

Wu, Sheldon S. Q.; Baker, Bradford W.; Rotter, Mark D.; Rubenchik, Alexander M.; Wiechec, Maxwell E.; Brown, Zachary M.; Beach, Raymond J.; Matthews, Manyalibo J.

2017-12-01

Localized heating of roughened steel surfaces using highly divergent laser light emitted from high-power laser diode arrays was experimentally demonstrated and compared with theoretical predictions. Polarization dependence was analyzed using Fresnel coefficients to understand the laser-induced temperature rise of HY-80 steel plates under 383- to 612-W laser irradiation. Laser-induced, transient temperature distributions were directly measured using bulk thermocouple probes and thermal imaging. Finite-element analysis yielded quantitative assessment of energy deposition and heat transport in HY-80 steel using absorptivity as a tuning parameter. The extracted absorptivity values ranged from 0.62 to 0.75 for S-polarized and 0.63 to 0.85 for P-polarized light, in agreement with partially oxidized iron surfaces. Microstructural analysis using electron backscatter diffraction revealed a heat affected zone for the highest temperature conditions (612 W, P-polarized) as evidence of rapid quenching and an austenite to martensite transformation. The efficient use of diode arrays for laser-assisted advanced manufacturing technologies, such as hybrid friction stir welding, is discussed.

Hydrogen effects on Ni-Ti fatigue performance by self -heating method

NASA Astrophysics Data System (ADS)

Rokbani, M.; Saint-Sulpice, L.; Arbab Chirani, S.; Bouraoui, T.

2017-10-01

Ni-Ti superelastic alloys are extensively used in manufacturing biomedical devices because of their high mechanical performance, good fatigue durability and biocompatibility compared to traditional metallic materials. During clinical use, most of these devices are intended to work under cyclic or repetitive loadings and may be in contact with corrosive environments leading to unexpected failures. It is however recognized that the fatigue-environment interaction, especially fatigue-hydrogen absorption, can be the main cause of these failures. The aim of this work is to investigate the fatigue behavior of superelastic Ni-Ti intended for manufacturing medical devices at high number of cycles (HCF) with a particular emphasis to the effect of hydrogen on fatigue properties. Fatigue tests were analyzed using self-heating measurements based on observing thermal effects during cyclic loadings. The results obtained with self-heating approach showed a trend of a decrease in the fatigue life of Ni-Ti alloys after hydrogen absorption and the fatigue limit extrapolated will be compared with the results obtained with the classical S-N curves method.

D2O clusters isolated in rare-gas solids: Dependence of infrared spectrum on concentration, deposition rate, heating temperature, and matrix material

NASA Astrophysics Data System (ADS)

Shimazaki, Yoichi; Arakawa, Ichiro; Yamakawa, Koichiro

2018-04-01

The infrared absorption spectra of D2O monomers and clusters isolated in rare-gas matrices were systematically reinvestigated under the control of the following factors: the D2O concentration, deposition rate, heating temperature, and rare-gas species. We clearly show that the cluster-size distribution is dependent on not only the D2O concentration but also the deposition rate of a sample; as the rate got higher, smaller clusters were preferentially formed. Under the heating procedures at different temperatures, the cluster-size growth was successfully observed. Since the monomer diffusion was not enough to balance the changes in the column densities of the clusters, the dimer diffusion was likely to contribute the cluster growth. The frequencies of the bonded-OD stretches of (D2O)k with k = 2-6 were almost linearly correlated with the square root of the critical temperature of the matrix material. Additional absorption peaks of (D2O)2 and (D2O)3 in a Xe matrix were assigned to the species trapped in tight accommodation sites.

Absorption and dissociative photoionization cross sections of NH3 from 80 to 1120 A

NASA Technical Reports Server (NTRS)

Samson, James A. R.; Haddad, G. N.; Kilcoyne, L. D.

1987-01-01

The total absorption, photoionization, and dissociative photoionization cross sections of ammonia have been measured from 80 to 1120 A. All possible fragment ions have been observed including doubly ionized ammonia. The absolute ionization efficiencies have also been measured in this spectral range. The appearance potentials of the fragment ions have been measured and are compared with the calculated appearance potentials derived from published heats of formation and ionization potentials of the fragments.

Diode Laser Pumped Alkali Vapor Lasers with Exciplex-Assisted Absorption

DTIC Science & Technology

2013-05-14

transfer agent that established the population inversion. The excitation source used in these initial studies was a pulsed optical parametric oscillator ...parametric oscillator . The lasers operated at 703.2 (Ne*), 912.5 (Ar*), 893.1 (Kr*) and 980.2 run (Xe*). Peak powers as high as 27kW/cm2 were observed...Larissa Glebova and Leonid B. Glebov. Ultra-low absorption and laser-induced heating of volume Bragg combiners recorded in photo-thermo- refractive

Elucidating the effects of solar panel waste glass substitution on the physical and mechanical characteristics of clay bricks.

PubMed

Lin, Kae-Long; Huang, Long-Sheng; Shie, Je-Lueng; Cheng, Ching-Jung; Lee, Ching-Hwa; Chang, Tien-Chin

2013-01-01

This study deals with the effect of solar panel waste glass on fired clay bricks. Brick samples were heated to temperatures which varied from 700-1000 degrees C for 6 h, with a heating rate of 10 degrees C min(-1). The material properties of the resultant material were then determined, including speciation variation, loss on ignition, shrinkage, bulk density, 24-h absorption rate, compressive strength and salt crystallization. The results indicate that increasing the amount of solar panel waste glass resulted in a decrease in the water absorption rate and an increase in the compressive strength of the solar panel waste glass bricks. The 24-h absorption rate and compressive strength of the solar panel waste glass brick made from samples containing 30% solar panel waste glass sintered at 1000 degrees C all met the Chinese National Standard (CNS) building requirements for first-class brick (compressive strengths and water absorption of the bricks were 300 kg cm(-2) and 10% of the brick, respectively). The addition of solar panel waste glass to the mixture reduced the degree of firing shrinkage. The salt crystallization test and wet-dry tests showed that the addition of solar panel waste glass had highly beneficial effects in that it increased the durability of the bricks. This indicates that solar panel waste glass is indeed suitable for the partial replacement of clay in bricks.

Infrared thermography based studies on mobile phone induced heating

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Bagavathiappan, S.; Soumya, C.; Jayakumar, T.; Philip, John

2015-07-01

Here, we report the skin temperature rise due to the absorption of radio frequency (RF) energy from three handheld mobile phones using infrared thermography technique. Experiments are performed under two different conditions, viz. when the mobile phones are placed in soft touch with the skin surface and away from the skin surface. Additionally, the temperature rise of mobile phones during charging, operation and simultaneous charging and talking are monitored under different exposure conditions. It is observed that the temperature of the cheek and ear regions monotonically increased with time during the usage of mobile phones and the magnitude of the temperature rise is higher for the mobile phone with higher specific absorption rate. The increase in skin temperature is higher when the mobile phones are in contact with the skin surface due to the combined effect of absorption of RF electromagnetic power and conductive heat transfer. The increase in the skin temperature in non-contact mode is found to be within the safety limit of 1 °C. The measured temperature rise is in good agreement with theoretical predictions. The empirical equation obtained from the temperature rise on the cheek region of the subjects correlates well with the specific absorption rate of the mobile phones. Our study suggests that the use of mobile phones in non-contact mode can significantly lower the skin temperature rise during its use and hence, is safer compared to the contact mode.

Dynamic Demos.

ERIC Educational Resources Information Center

Sae, Andy S. W.

1991-01-01

Discusses 27 chemical demonstrations involving inexpensive, readily available materials that illustrate the following concepts: acid/base properties, gas properties, characteristics of carbon dioxide, chemiluminescence, freezing point depression, heat of vaporization; density, polymers, surface tension, polarity/nonpolarity, UV absorption,…

LASE

Atmospheric Science Data Center

2017-03-16

... Absorption Lidar (DIAL) system developed to measure water vapor, aerosol, and cloud profiles. These measurements can be used in ... heat flux, the water vapor component of the hydrologic cycle, and atmospheric transport using water vapor as a tracer of atmospheric ...

Gas absorption/desorption temperature-differential engine

NASA Technical Reports Server (NTRS)

Miller, C. G.

1981-01-01

Continuously operating compressor system converts 90 percent of gas-turbine plant energy to electricity. Conventional plants work in batch mode, operating at 40 percent efficiency. Compressor uses metal hydride matrix on outside of rotating drum to generate working gas, hydrogen. Rolling valve seals allow continuous work. During operation, gas is absorbed, releasing heat, and desorbed with heat gain. System conserves nuclear and fossil fuels, reducing powerplant capital and operating costs.

Nonequilibrium quantum absorption refrigerator

NASA Astrophysics Data System (ADS)

Du, Jian-Ying; Zhang, Fu-Lin

2018-06-01

We study a quantum absorption refrigerator, in which a target qubit is cooled by two machine qubits in a nonequilibrium steady-state. It is realized by a strong internal coupling in the two-qubit fridge and a vanishing tripartite interaction among the whole system. The coherence of a machine virtual qubit is investigated as quantumness of the fridge. A necessary condition for cooling shows that the quantum coherence is beneficial to the nonequilibrium fridge, while it is detrimental as far as the maximum coefficient of performance (COP) and the COP at maximum power are concerned. Here, the COP is defined only in terms of heat currents caused by the tripartite interaction, with the one maintaining the two-qubit nonequilibrium state being excluded. The later can be considered to have no direct involvement in extracting heat from the target, as it is not affected by the tripartite interaction.

Enhanced laser absorption from radiation pressure in intense laser plasma interactions

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

Dollar, F.; Zulick, C.; Raymond, A.

The reflectivity of a short-pulse laser at intensities of 2 x 10 21Wcm -2 with ultra-high contrast (10 -15) on sub-micrometer silicon nitride foilswas studied experimentally using varying polarizations and target thicknesses. Furthermore, the reflected intensity and beam quality were found to be relatively constant with respect to intensity for bulk targets. For submicron targets, the measured reflectivity drops substantially without a corresponding increase in transmission, indicating increased conversion of fundamental to other wavelengths and particle heating. The experimental results and trends we observed in 3D particle-in-cell simulations emphasize the critical role of ion motion due to radiation pressure onmore » the absorption process. Ion motion during ultra-short pulses enhances the electron heating, which subsequently transfers more energy to the ions.« less

Enhanced laser absorption from radiation pressure in intense laser plasma interactions

DOE PAGES

Dollar, F.; Zulick, C.; Raymond, A.; ...

2017-06-06

The reflectivity of a short-pulse laser at intensities of 2 x 10 21Wcm -2 with ultra-high contrast (10 -15) on sub-micrometer silicon nitride foilswas studied experimentally using varying polarizations and target thicknesses. Furthermore, the reflected intensity and beam quality were found to be relatively constant with respect to intensity for bulk targets. For submicron targets, the measured reflectivity drops substantially without a corresponding increase in transmission, indicating increased conversion of fundamental to other wavelengths and particle heating. The experimental results and trends we observed in 3D particle-in-cell simulations emphasize the critical role of ion motion due to radiation pressure onmore » the absorption process. Ion motion during ultra-short pulses enhances the electron heating, which subsequently transfers more energy to the ions.« less

Numerical investigation for entropy generation in hydromagnetic flow of fluid with variable properties and slip

NASA Astrophysics Data System (ADS)

Khan, M. Ijaz; Hayat, Tasawar; Alsaedi, Ahmed

2018-02-01

This modeling and computations present the study of viscous fluid flow with variable properties by a rotating stretchable disk. Rotating flow is generated through nonlinear rotating stretching surface. Nonlinear thermal radiation and heat generation/absorption are studied. Flow is conducting for a constant applied magnetic field. No polarization is taken. Induced magnetic field is not taken into account. Attention is focused on the entropy generation rate and Bejan number. The entropy generation rate and Bejan number clearly depend on velocity and thermal fields. The von Kármán approach is utilized to convert the partial differential expressions into ordinary ones. These expressions are non-dimensionalized, and numerical results are obtained for flow variables. The effects of the magnetic parameter, Prandtl number, radiative parameter, heat generation/absorption parameter, and slip parameter on velocity and temperature fields as well as the entropy generation rate and Bejan number are discussed. Drag forces (radial and tangential) and heat transfer rates are calculated and discussed. Furthermore the entropy generation rate is a decreasing function of magnetic variable and Reynolds number. The Bejan number effect on the entropy generation rate is reverse to that of the magnetic variable. Also opposite behavior of heat transfers is observed for varying estimations of radiative and slip variables.

Compact sieve-tray distillation column for ammonia-water absorption heat pump: Part 1 -- Design methodology

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

Anand, G.; Erickson, D.C.

1999-07-01

The distillation column is a key component of ammonia-water absorption units including advanced generator-absorber heat exchange (GAX) cycle heat pumps. The design of the distillation column is critical to unit performance, size, and cost. The distillation column can be designed with random packing, structured packing, or various tray configurations. A sieve-tray distillation column is the least complicated tray design and is less costly than high-efficiency packing. Substantial literature is available on sieve tray design and performance. However, most of the correlations and design recommendations were developed for large industrial hydrocarbon systems and are generally not directly applicable to the compactmore » ammonia-water column discussed here. The correlations were reviewed and modified as appropriate for this application, and a sieve-tray design model was developed. This paper presents the sieve-tray design methodology for highly compact ammonia-water columns. A conceptual design of the distillation column for an 8 ton vapor exchange (VX) GAX heat pump is presented, illustrating relevant design parameters and trends. The design process revealed several issues that have to be investigated experimentally to design the final optimized rectifier. Validation of flooding and weeping limits and tray/point efficiencies are of primary importance.« less

Mark-forming simulations of phase-change land/groove disks

NASA Astrophysics Data System (ADS)

Nishi, Yoshiko; Shimano, Takeshi; Kando, Hidehiko

2000-09-01

The track pitches of optical discs have become so narrow that it is comparable to the wavelength of laser beam. Finite-difference time-domain (FDTD) simulation, based on vector diffraction analysis, can predict the propagation of light more accurately than scalar analysis, when the size of media texture becomes sub-micron order. The authors applied FDTD simulation to land-and-groove optical disc models, and found out that the effects of 3D geometry is not negligible in analyzing the energy absorption of light inside the land- and-groove multi-layered media. The electromagnetic field in the media does not have the same intensity distribution as the incident beam. Furthermore, the heat conduction inside the media depends on the disc geometry, so the beam spots centered on land and groove makes different effects in heating the recording layers. That is, the spatial and historical profile of temperature requires 3D analysis for both incident light absorption and heat conduction. The difference in temperature profiles is applied to the phase change simulator to see the writing process of the marks in land and groove. We have integrated three simulators: FDTD analysis, heat conduction and phase change simulation. These simulators enabled to evaluate the differences in mark forming process between land and groove.

Effects of soot absorption coefficient-Planck function correlation on radiative heat transfer in oxygen-enriched propane turbulent diffusion flame

NASA Astrophysics Data System (ADS)

Consalvi, J. L.; Nmira, F.

2016-03-01

The main objective of this article is to quantify the influence of the soot absorption coefficient-Planck function correlation on radiative loss and flame structure in an oxygen-enhanced propane turbulent diffusion flame. Calculations were run with and without accounting for this correlation by using a standard k-ε model and the steady laminar flamelet model (SLF) coupled to a joint Probability Density Function (PDF) of mixture fraction, enthalpy defect, scalar dissipation rate, and soot quantities. The PDF transport equation is solved by using a Stochastic Eulerian Field (SEF) method. The modeling of soot production is carried out by using a flamelet-based semi-empirical acetylene/benzene soot model. Radiative heat transfer is modeled by using a wide band correlated-k model and turbulent radiation interactions (TRI) are accounted for by using the Optically-Thin Fluctuation Approximation (OTFA). Predicted soot volume fraction, radiant wall heat flux distribution and radiant fraction are in good agreement with the available experimental data. Model results show that soot absorption coefficient and Planck function are negatively correlated in the region of intense soot emission. Neglecting this correlation is found to increase significantly the radiative loss leading to a substantial impact on flame structure in terms of mean and rms values of temperature. In addition mean and rms values of soot volume fraction are found to be less sensitive to the correlation than temperature since soot formation occurs mainly in a region where its influence is low.

Thermo-plasmonics: playing with temperature at the nanoscale (Conference Presentation)

NASA Astrophysics Data System (ADS)

Alabastri, Alessandro; Malerba, Mario; Calandrini, Eugenio; Toma, Andrea; Proietti Zaccaria, Remo

2017-02-01

The electro-magnetic field generated within and around dissipative nano-structures upon light radiation is intimately associated to the formation of localized heat sources. In turn, this phenomenon determines localized temperature variations, effect which can be exploited for applications such as photocatalysis [1], nanochemistry [2] or sensor devices [3]. Here we show how the geometrical characteristics of plasmonic nano-structures can indeed be used to modulate the temperature response. The idea is that when metallic structures interact with an electromagnetic field they heat up due to Joule effect. The corresponding temperature variation modifies the optical response of the structure [4,5] and thus its heating process. The key finding is that, depending on the structures geometry, absorption efficiency can either increase or decrease with temperature. Since absorption relates to the thermal energy dissipation and thus to temperature increase, the mechanism leads to positive or negative loops. Consequently, not only an error would be made by neglecting the role of temperature, but it would be not even possible to know, a priori, if the error is towards higher or lower absorption values. Our model can be utilized to study opto-thermal phenomena when high temperature or high intensity sources are employed. [1] M. Honda et al., Appl. Phys. Lett. 104, 061108 (2014) [2] G. Baffou et al., Chem. Soc. Rev. 43, 3898 (2014) [3] S. Ozdemir et al., J. Lightwave Tech. 21, 805 (2003) [4] A. Alabastri et al., ACS Photonics 2, 115 (2015) [5] A. Alabastri et al., Materials 6, 4879 (2013)

Synergistic effect of surface self-doping and Fe species-grafting for enhanced photocatalytic activity of TiO2 under visible-light

NASA Astrophysics Data System (ADS)

Kong, Lina; Wang, Changhua; Wan, Fangxu; Zheng, Han; Zhang, Xintong

2017-02-01

Surface grafting of transition-metal complexes or oxides is an appealing way to enhance the photocatalytic activity of TiO2 under visible-light excitation. However, the performance of these co-catalysts assistant TiO2 photocatalysts is still not sufficient enough due to their relatively weak visible-light absorption. Herein, we report a simple impregnation treatment with ferric ethoxide/ethanol solvent, followed with mild heating which can significantly enhance the visible-light absorption and photocatalytic activity of TiO2. XPS and EPR analyses manifest that the oxygen vacancies (VOs) and Fe-species are simultaneously introduced to the surface of TiO2. The chemical state and photocatalytic activity of the Fe-species-grafted TiO2 - x is dependent on the heating temperature after impregnation. The sample heat-treated at 250 °C exhibits the optimal photocatalytic performance for β-naphthol degradation with rate constant 6.0, 2.7, and 3.9 times higher than that of TiO2, TiO2 - x, and Fe-TiO2, respectively. The activity enhancement is discussed on the basis of the synergistic effect and energy-level matching of surface VOs and Fe-species co-catalyst, i.e. the VOs defects states increase the visible-light absorption and the Fe-species in the form of FeOOH promote the consumption of photo-generated electrons through multi-electron reduction of adsorbed molecule oxygen.

Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for Measurements of Atmospheric Ammonia

NASA Astrophysics Data System (ADS)

Ellis, R.; Murphy, J. G.; van Haarlem, R.; Pattey, E.; O'Brien, J.

2009-05-01

A compact, fast response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC- TILDAS) for measurements of ammonia has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 76 m path length, 0.5 L volume multiple pass absorption cell. Detection is achieved using a thermoelectrically cooled HgCdTe infrared detector. A novel sampling technique was used, consisting of a short, heated, quartz inlet with a hydrophobic coating to minimize the adsorption of ammonia to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles and additional ports for delivering ammonia free background air and calibration gas standards. This instrument has been found to have a detection limit of 0.3 ppb with a time resolution of 1 s. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser (TDL) absorption spectrometer during a laboratory intercomparison. Various lengths and types of sample inlet tubing material, heated and unheated, under dry and ambient humidity conditions with ammonia concentrations ranging from 10-1000 ppb were investigated. Preliminary analysis suggests the time response improves with the use of short, PFA tubing sampling lines. No significant improvement was observed when using a heated sampling line and humidity was seen to play an important role on the bi-exponential decay of ammonia. A field intercomparison of the QC-TILDAS with a modified Thermo 42C chemiluminescence based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE) in the rural town of Egbert, ON between May-July 2008. Background tests and calibrations using two different permeation tube sources and an ammonia gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation (r2>0.9) between the two instruments at the beginning of the study, when regular background subtraction was applied to the QC- TILDAS.

Solar Selective Coatings Prepared From Thin-Film Molecular Mixtures and Evaluated

NASA Technical Reports Server (NTRS)

Jaworske, Don A.

2003-01-01

Thin films composed of molecular mixtures of metal and dielectric are being considered for use as solar selective coatings for a variety of space power applications. By controlling molecular mixing during ion-beam sputter deposition, researchers can tailor the solar selective coatings to have the combined properties of high solar absorptance and low infrared emittance. On orbit, these combined properties simultaneously maximize the amount of solar energy captured by the coating and minimize the amount of thermal energy radiated. The solar selective coatings are envisioned for use on minisatellites, for applications where solar energy is used to power heat engines or to heat remote regions in the interior of the spacecraft. Such systems may be useful for various missions, particularly those to middle Earth orbit. Sunlight must be concentrated by a factor of 100 or more to achieve the desired heat inlet operating temperature. At lower concentration factors, the temperature of the heat inlet surface of the heat engine is too low for efficient operation, and at high concentration factors, cavity type heat receivers become attractive. The an artist's concept of a heat engine, with the annular heat absorbing surface near the focus of the concentrator coated with a solar selective coating is shown. In this artist's concept, the heat absorbing surface powers a small Stirling convertor. The astronaut's gloved hand is provided for scale. Several thin-film molecular mixtures have been prepared and evaluated to date, including mixtures of aluminum and aluminum oxide, nickel and aluminum oxide, titanium and aluminum oxide, and platinum and aluminum oxide. For example, a 2400- Angstrom thick mixture of titanium and aluminum oxide was found to have a solar absorptance of 0.93 and an infrared emittance of 0.06. On the basis of tests performed under flowing nitrogen at temperatures as high as 680 C, the coating appeared to be durable at elevated temperatures. Additional durability testing is planned, including exposure to atomic oxygen, vacuum ultraviolet radiation, and high-energy electrons.

JET (3He)-D scenarios relying on RF heating: survey of selected recent experiments

NASA Astrophysics Data System (ADS)

Van Eester, D.; Lerche, E.; Andrew, Y.; Biewer, T. M.; Casati, A.; Crombé, K.; de la Luna, E.; Ericsson, G.; Felton, R.; Giacomelli, L.; Giroud, C.; Hawkes, N.; Hellesen, C.; Hjalmarsson, A.; Joffrin, E.; Källne, J.; Kiptily, V.; Lomas, P.; Mantica, P.; Marinoni, A.; Mayoral, M.-L.; Ongena, J.; Puiatti, M.-E.; Santala, M.; Sharapov, S.; Valisa, M.; JET EFDA contributors

2009-04-01

Recent JET experiments have been devoted to the study of (3He)-D plasmas involving radio frequency (RF) heating. This paper starts by discussing the RF heating efficiency theoretically expected in such plasmas, covering both relevant aspects of wave and of particle dynamics. Then it gives a concise summary of the main conclusions drawn from recent experiments that were either focusing on studying RF heating physics aspects or that were adopting RF heating as a tool to study plasma behavior. Depending on the minority concentration chosen, different physical phenomena are observed. At very low concentration (X[3He] < 1%), energetic tails are formed which trigger MHD activity and result in loss of fast particles. Alfvén cascades were observed and gamma ray tomography indirectly shows the impact of sawtooth crashes on the fast particle orbits. Low concentration (X[3He] < 10%) favors minority heating while for X[3He] Gt 10% electron mode conversion damping becomes dominant. Evidence for the Fuchs et al standing wave effect (Fuchs et al 1995 Phys. Plasmas 2 1637-47) on the absorption is presented. RF induced deuterium tails were observed in mode conversion experiments with large X[3He] (≈18%). As tentative modeling shows, the formation of these tails can be explained as a consequence of wave power absorption by neutral beam particles that efficiently interact with the waves well away from the cold D cyclotron resonance position as a result of their substantial Doppler shift. As both ion and electron RF power deposition profiles in (3He)-D plasmas are fairly narrow—giving rise to localized heat sources—the RF heating method is an ideal tool for performing transport studies. Various of the experiments discussed here were done in plasmas with internal transport barriers (ITBs). ITBs are identified as regions with locally reduced diffusivity, where poloidal spinning up of the plasma is observed. The present know-how on the role of RF heating for impurity transport is also briefly summarized.

Simulation of heating by optical absorption in nanoparticle dispersions (Conference Presentation)

NASA Astrophysics Data System (ADS)

Olbricht, Benjamin C.

2017-02-01

With the proliferation of highly confined, nanophotonic waveguides and laser sources with increasing intensity, the effects of laser heating will begin to greatly impact the materials used in optical applications. In order to better understand the mechanism of laser heating, its timescales, and the dispersion of heat into the material, simulations of nanoparticles in various media are presented. A generic model to describe a variety of nanoparticle shapes and sizes is desirable to describe complex phenomenon. These particles are dispersed into various solids, liquids, or gases depending on the application. To simulate nanoparticles and their interaction with their host material, the Finite Element Method (FEM) is used. Heat transfer following an absorption event is also described by a parabolic partial differential equation, and transient solutions are generated in response to continuous, pulsed, or modulated laser radiation. The simplest physical system described by FEM is that of a broadly-absorbing round-shaped nanoparticle dispersed in viscous host fluid or solid. Many experimental and theoretical studies conveniently describe a very similar system: a carbon "black" nanoparticle suspended in water. This material is well-known to exhibit nonlinear behavior when a laser pulse carrying 0.7 J/cm2 is incident on the material. For this process the FEM simulations agree with experimental results to show that a pulse of this fluence is capable of heating the solvent elements adjacent to the nanoparticle to their boiling point. This creates nonlinear scattering which is empirically observed as a nonlinear decrease in the transmitted power at this input fluence.

Sensible heat has significantly affected the global hydrological cycle over the historical period.

PubMed

Myhre, G; Samset, B H; Hodnebrog, Ø; Andrews, T; Boucher, O; Faluvegi, G; Fläschner, D; Forster, P M; Kasoar, M; Kharin, V; Kirkevåg, A; Lamarque, J-F; Olivié, D; Richardson, T B; Shawki, D; Shindell, D; Shine, K P; Stjern, C W; Takemura, T; Voulgarakis, A

2018-05-15

Globally, latent heating associated with a change in precipitation is balanced by changes to atmospheric radiative cooling and sensible heat fluxes. Both components can be altered by climate forcing mechanisms and through climate feedbacks, but the impacts of climate forcing and feedbacks on sensible heat fluxes have received much less attention. Here we show, using a range of climate modelling results, that changes in sensible heat are the dominant contributor to the present global-mean precipitation change since preindustrial time, because the radiative impact of forcings and feedbacks approximately compensate. The model results show a dissimilar influence on sensible heat and precipitation from various drivers of climate change. Due to its strong atmospheric absorption, black carbon is found to influence the sensible heat very differently compared to other aerosols and greenhouse gases. Our results indicate that this is likely caused by differences in the impact on the lower tropospheric stability.

Thermal control systems for low-temperature heat rejection on a lunar base

NASA Technical Reports Server (NTRS)

Sridhar, K. R.; Gottmann, Matthias; Nanjundan, Ashok

1993-01-01

One of the important issues in the design of a lunar base is the thermal control system (TCS) used to reject low-temperature heat from the base. The TCS ensures that the base and the components inside are maintained within an acceptable temperature range. The temperature of the lunar surface peaks at 400 K during the 336-hour lunar day. Under these circumstances, direct dissipation of waste heat from the lunar base using passive radiators would be impractical. Thermal control systems based on thermal storage, shaded radiators, and heat pumps have been proposed. Based on proven technology, innovation, realistic complexity, reliability, and near-term applicability, a heat pump-based TCS was selected as a candidate for early missions. In this report, Rankine-cycle heat pumps and absorption heat pumps (ammonia water and lithium bromide-water) have been analyzed and optimized for a lunar base cooling load of 100 kW.

Transient Heat Transfer in a Semitransparent Radiating Layer with Boundary Convection and Surface Reflections

NASA Technical Reports Server (NTRS)

Siegel, Robert

1996-01-01

Surface convection and refractive index are examined during transient radiative heating or cooling of a grey semitransparent layer with internal absorption, emission and conduction. Each side of the layer is exposed to hot or cold radiative surroundings, while each boundary is heated or cooled by convection. Emission within the layer and internal reflections depend on the layer refractive index. The reflected energy and heat conduction distribute energy across the layer and partially equalize the transient temperature distributions. Solutions are given to demonstrate the effect of radiative heating for layers with various optical thicknesses, the behavior of the layer heated by radiation on one side and convectively cooled on the other, and a layer heated by convection while being cooled by radiation. The numerical method is an implicit finite difference procedure with non-uniform space and time increments. The basic method developed in earlier work is expanded to include external convection and incident radiation.

Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration

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

Bansal, Pradeep; Vineyard, Edward Allan; Abdelaziz, Omar

This paper presents a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications. Such technologies are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use. These alternative technologies include: thermoacoustic refrigeration, thermoelectric refrigeration, thermotunneling, magnetic refrigeration, Stirling cycle refrigeration, pulse tube refrigeration, Malone cycle refrigeration, absorption refrigeration, adsorption refrigeration, and compressor driven metal hydride heat pumps. Furthermore, heat pump water heating and integrated heat pump systems are also discussed due to their significant energy saving potential for water heating and space conditioningmore » in households. The paper provides a snapshot of the future R&D needs for each of the technologies along with the associated barriers. Both thermoelectric and magnetic technologies look relatively attractive due to recent developments in the materials and prototypes being manufactured.« less

Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Ranoo, Surojit; Philip, John

2017-11-01

Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ~25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and the results are compared using a lumped system thermal model. The various uncertainties involved in SAR estimation are categorized as material uncertainties, thermodynamic uncertainties and parametric uncertainties. The adiabatic reconstruction is found to decrease the uncertainties in SAR measurement by approximately three times. Additionally, a set of experimental guidelines for accurate SAR estimation using adiabatic reconstruction protocol is also recommended. These results warrant a universal experimental and data analysis protocol for SAR measurements during field induced heating of magnetic fluids under non-adiabatic conditions.

Molecular Composition Analysis of Distant Targets

NASA Technical Reports Server (NTRS)

Hughes, Gary B.; Lubin, Philip

2017-01-01

This document is the Final Report for NASA Innovative Advanced Concepts (NIAC) Phase I Grant 15-NIAC16A-0145, titled Molecular Composition Analysis of Distant Targets. The research was focused on developing a system concept for probing the molecular composition of cold solar system targets, such as Asteroids, Comets, Planets and Moons from a distant vantage, for example from a spacecraft that is orbiting the target (Hughes et al., 2015). The orbiting spacecraft is equipped with a high-power laser, which is run by electricity from photovoltaic panels. The laser is directed at a spot on the target. Materials on the surface of the target are heated by the laser beam, and begin to melt and then evaporate, forming a plume of asteroid molecules in front of the heated spot. The heated spot glows, producing blackbody illumination that is visible from the spacecraft, via a path through the evaporated plume. As the blackbody radiation from the heated spot passes through the plume of evaporated material, molecules in the plume absorb radiation in a manner that is specific to the rotational and vibrational characteristics of the specific molecules. A spectrometer aboard the spacecraft is used to observe absorption lines in the blackbody signal. The pattern of absorption can be used to estimate the molecular composition of materials in the plume, which originated on the target. Focusing on a single spot produces a borehole, and shallow subsurface profiling of the targets bulk composition is possible. At the beginning of the Phase I research, the estimated Technology Readiness Level (TRL) of the system was TRL-1. During the Phase I research, an end-to-end theoretical model of the sensor system was developed from first principles. The model includes laser energy and optical propagation, target heating, melting and evaporation of target material, plume density, thermal radiation from the heated spot, molecular cross section of likely asteroid materials, and estimation of the absorption profile at a distant spectrometer. Results obtained by executing simulations based on the model provide compelling evidence that the concept of remote laser evaporative molecular absorption spectroscopy is feasible. In this document, technical details of the model are presented, and results of simulations are described that indicate the utility of the proposed sensor system. Additionally, an asteroid rendezvous mission is analyzed, with a survey of system requirements to accomplish molecular composition analysis of the asteroid. Based on positive theoretical results obtained during Phase I, the estimated TRL of the system is now TRL-2. This document also describes potential future research and experimentation that could push the system to TRL-4 within 2 years. Steps required for construction of a laboratory prototype are described. An experiment to test predictions of the theory is described, based on the laboratory prototype setup.

Initial operation of a solar heating and cooling system in a full-scale solar building test facility

NASA Technical Reports Server (NTRS)

Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.

1976-01-01

The Solar Building Test Facility (SBTF) was constructed to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test the performance of a complete solar heating and cooling system, (3) investigate component interactions, and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is printed along with the objectives, test approach, expected system performance, and some preliminary results.

Chemical heat pump

DOEpatents

Greiner, Leonard

1984-01-01

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.

Chemical heat pump

DOEpatents

Greiner, Leonard

1981-01-01

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.

Chemical heat pump

DOEpatents

Greiner, Leonard

1984-01-01

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate intallation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.

Chemical heat pump

DOEpatents

Greiner, Leonard

1984-01-01

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to faciliate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.

Absorption generator for solar-powered air-conditioner

NASA Technical Reports Server (NTRS)

Lowen, D. J.; Murray, J. G.

1977-01-01

Device passes solar-heated water through coils. Hot lithium Bromide/Water solution leaves through central stand-pipe, and water vapor leaves through refrigerant outlet at top. Matching generation temperature to collector efficiency helps cut costs.

Gold nanoparticles: enhanced optical trapping and sensitivity coupled with significant heating.

PubMed

Seol, Yeonee; Carpenter, Amanda E; Perkins, Thomas T

2006-08-15

Gold nanoparticles appear to be superior handles in optical trapping assays. We demonstrate that relatively large gold particles (R(b)=50 nm) indeed yield a sixfold enhancement in trapping efficiency and detection sensitivity as compared to similar-sized polystyrene particles. However, optical absorption by gold at the most common trapping wavelength (1064 nm) induces dramatic heating (266 degrees C/W). We determined this heating by comparing trap stiffness from three different methods in conjunction with detailed modeling. Due to this heating, gold nanoparticles are not useful for temperature-sensitive optical-trapping experiments, but may serve as local molecular heaters. Also, such particles, with their increased detection sensitivity, make excellent probes for certain zero-force biophysical assays.

Performance evaluation of the Solar Building Test Facility

NASA Technical Reports Server (NTRS)

Jensen, R. N.

1981-01-01

The general performance of the NASA Solar Building Test Facility (SBTF) and its subsystems and components over a four year operational period is discussed, and data are provided for a typical one year period. The facility consists of a 4645 sq office building modified to accept solar heated water for operation of an absorption air conditioner and a baseboard heating system. An adjoining 1176 sq solar flat plate collector field with a 114 cu tank provides the solar heated water. The solar system provided 57 percent of the energy required for heating and cooling on an annual basis. The average efficiency of the solar collectors was 26 percent over a one year period.

The relationship of temperature rise to specific absorption rate and current in the human leg for exposure to electromagnetic radiation in the high frequency band.

PubMed

Wainwright, P R

2003-10-07

Of the biological effects of human exposure to radiofrequency and microwave radiation, the best-established are those due to elevation of tissue temperature. To prevent harmful levels of heating, restrictions have been proposed on the specific absorption rate (SAR). However, the relationship between SAR and temperature rise is not an invariant, since not only the heat capacity but also the efficiency of heat dissipation varies between different tissues and exposure scenarios. For small enough SAR, the relationship is linear and may be characterized by a 'heating factor' deltaT/SAR. Under whole-body irradiation the SAR may be particularly high in the ankles due to the concentration of current flowing through a relatively small cross-sectional area. In a previous paper, the author has presented calculations of the SAR distribution in a human leg in the high frequency (HF) band. In this paper, the heating factor for this situation is derived using a finite element approximation of the Pennes bioheat equation. The sensitivity of the results to different blood perfusion rates is investigated, and a simple local thermoregulatory model is applied. Both time-dependent and steady-state solutions are considered. Results confirm the appropriateness of the ICNIRP reference level of 100 mA on current through the leg, but suggest that at higher currents significant thermoregulatory adjustments to muscle blood flow will occur.

Experimental study on emission of VOCs from tanker using hollow fiber membrane absorption method with different absorbents

NASA Astrophysics Data System (ADS)

Zhou, J. Y.; Wang, B. F.; Nie, L. H.; Lu, J. X.; Hao, Y. J.; Xu, R. R.

2018-01-01

China’s oil dependence is getting higher and higher, 90% of oil import is transported by sea. Tankers will produce a lot of VOCs during loading and unloading, so the prevention of such pollution has become increasingly urgent. The hollow fiber membrane absorption method combined the characteristics of the absorption method for the treatment of high concentration and large flow of VOCs and the advantage of low energy consumption of membrane method. At present, the research on the recovery of oil and gas is relatively few. In this paper, the effect of membrane absorption on the recovery of oil and gas was investigated. The different absorbent affected the oil vapor recovery, the experimental results showed that the performance of absorbent of AbsFOV-97 was better than that of heat conductive oil.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Frequency modulation upon nonstationary heating of the p - n junction in high-sensitive diode laser spectroscopy

NASA Astrophysics Data System (ADS)

Andreev, Sergei N.; Nikolaev, I. V.; Ochkin, Vladimir N.; Savinov, Sergei Yu; Spiridonov, Maksim V.; Tskhai, Sergei N.

2007-04-01

A special type of modulation of the injection current of a diode laser is proposed at which the frequency modulation of radiation is not accompanied by the residual amplitude modulation. This method considerably reduces the influence of the diode laser radiation instability on the recorded absorption spectra. This allows a prolonged monitoring of small amounts of impurities in gas analysis by retaining a high sensitivity. Prolonged measurements of absorption spectra are performed at a relative absorption of 8×10-7. By using a 50-cm multipass cell with the optical length of 90 m, the absorption coefficient of 1.2×10-10 cm-1 was detected. As an example, the day evolution of the background concentrations of NO2 molecules was measured in the atmosphere.

Simulation model of a single-stage lithium bromide-water absorption cooling unit

NASA Technical Reports Server (NTRS)

Miao, D.

1978-01-01

A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

Characterization of selective solar absorber under high vacuum.

PubMed

Russo, Roberto; Monti, Matteo; di Giamberardino, Francesco; Palmieri, Vittorio G

2018-05-14

Total absorption and emission coefficients of selective solar absorbers are measured under high vacuum conditions from room temperature up to stagnation temperature. The sample under investigation is illuminated under vacuum @1000W/m 2 and the sample temperature is recorded during heat up, equilibrium and cool down. During stagnation, the absorber temperature exceeds 300°C without concentration. Data analysis allows evaluating the solar absorptance and thermal emittance at different temperatures. These in turn are useful to predict evacuated solar panel performances at operating conditions.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, R.C.; Biermann, W.J.

1993-04-27

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, Robert C.; Biermann, Wendell J.

1993-01-01

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Three Dimensional Reconstruction Algorithm for Imaging Pathophysiological Signals Within Breast Tissue Using Near Infrared Light

DTIC Science & Technology

2006-07-01

months.31 A heated mixture of water, gelatin (G2625, Sigma Inc.), India ink (for absorption), and titanium dioxide powder (for scatter) (TiO2, Sigma Inc...for absorption, and titanium dioxide powder for scat- ter TiO2, Sigma Inc. that are solidified by cooling to room temperature. Optically...2713-2727. 8. Bolin, F.P., Preuss, L. E., Taylor, R. C., Ference, R. J, Refractive index of some mammalian tissue using a fiber optic cladding method

Numerical simulation of the shape of laser cut for fiber and CO2 lasers

NASA Astrophysics Data System (ADS)

Zaitsev, A. V.; Ermolaev, G. V.; Polyanskiy, T. A.; Gurin, A. M.

2017-10-01

The results of numerical modeling of steel plate laser cutting with nitrogen as assist gas with consideration of heat transfer into a bulk material are presented. In this work we studied a distribution of absorbed radiation energy inside cut kerf and the difference between CO2 and fiber laser radiation propagation and absorption. The influence of secondary absorption of reflected from the cut front radiation on stability of melt hydrodynamics is discussed for different laser types.

Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

DOE PAGES

Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

2015-02-01

The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

Contamination in Orbit of GOES-8

NASA Technical Reports Server (NTRS)

Sanders, Jack T.

2002-01-01

The GOES-8 satellite has lost some of its ability to dissipate heat over time. This is shown by the temperature increases over time of spacecraft and instrument components that are cooled with optical solar reflector (OSR) radiators. Contamination has a significant, well-documented effect on the solar absorptance (a(sub s)) of OSRs. This document attempts to discern how much molecular contamination has collected on the Imager and Sounder radiant coolers by analyzing the increase in temperature of the vacuum cooler housing. In the first part, temperature change is transformed into solar absorptance units by a method devised by ITT. The second part transfomis the solar absorptance gain into a molecular film thickness.

Simulations of High Harmonic Fast Wave Heating on the C-2U Advanced Beam-Driven Field-Reversed Configuration Device

NASA Astrophysics Data System (ADS)

Yang, Xiaokang; Petrov, Yuri; Ceccherini, Francesco; Koehn, Alf; Galeotti, Laura; Dettrick, Sean; Binderbauer, Michl

2017-10-01

Numerous efforts have been made at Tri-Alpha Energy (TAE) to theoretically explore the physics of microwave electron heating in field-reversed configuration (FRC) plasmas. For the fixed 2D profiles of plasma density and temperature for both electrons and thermal ions and equilibrium field of the C-2U machine, simulations with GENRAY-C ray-tracing code have been conducted for the ratios of ω/ωci[D] in the range of 6 - 20. Launch angles and antenna radial and axial positions have been optimized in order to simultaneously achieve good wave penetration into the core of FRC plasmas and efficient power damping on electrons. It is found that in an optimal regime, single pass absorption efficiency is 100% and most of the power is deposited inside the separatrix of FRC plasmas, with power damping efficiency of about 72% on electrons and less than 19% on ions. Calculations have clearly demonstrated that substantial power absorption on electrons is mainly attributed to high beta enhancement of magnetic pumping; complete power damping occurs before Landau damping has a significant effect on power absorption.

Experimental Study of Ultrasound Contrast Agent Mediated Heat Transfer for Therapeutic Applications

NASA Astrophysics Data System (ADS)

Razansky, D.; Adam, D. R.; Einziger, P. D.

2006-05-01

Ultrasound Contrast Agents (UCA) have been recently suggested as efficient enhancers of ultrasonic power deposition in tissue. The ultrasonic energy absorption by UCA, considered as disadvantageous in diagnostic imaging, might be valuable in therapeutic applications such as targeted hyperthermia or ablation treatments. The current study, based on theoretical predictions, was designed to experimentally measure the dissipation and heating effects of encapsulated UCA (Optison™) in a well-controlled and calibrated environment.