Quantifying Wheat Sensitivities to Environmental Constraints to Dissect Genotype × Environment Interactions in the Field1[OPEN

PubMed Central

Maphosa, Lance; Kovalchuk, Alex

2017-01-01

Yield is subject to strong genotype-by-environment (G × E) interactions in the field, especially under abiotic constraints such as soil water deficit (drought [D]) and high temperature (heat [H]). Since environmental conditions show strong fluctuations during the whole crop cycle, geneticists usually do not consider environmental measures as quantitative variables but rather as factors in multienvironment analyses. Based on 11 experiments in a field platform with contrasting temperature and soil water deficit, we determined the periods of sensitivity to drought and heat constraints in wheat (Triticum aestivum) and determined the average sensitivities for major yield components. G × E interactions were separated into their underlying components, constitutive genotypic effect (G), G × D, G × H, and G × H × D, and were analyzed for two genotypes, highlighting contrasting responses to heat and drought constraints. We then tested the constitutive and responsive behaviors of two strong quantitative trait loci (QTLs) associated previously with yield components. This analysis confirmed the constitutive effect of the chromosome 1B QTL and explained the G × E interaction of the chromosome 3B QTL by a benefit of one allele when temperature rises. In addition to the method itself, which can be applied to other data sets and populations, this study will support the cloning of a major yield QTL on chromosome 3B that is highly dependent on environmental conditions and for which the climatic interaction is now quantified. PMID:28546436

Controlled Microwave Heating Accelerates Rolling Circle Amplification

PubMed Central

Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

2015-01-01

Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same. PMID:26348227

Quantifying Wheat Sensitivities to Environmental Constraints to Dissect Genotype × Environment Interactions in the Field.

PubMed

Parent, Boris; Bonneau, Julien; Maphosa, Lance; Kovalchuk, Alex; Langridge, Peter; Fleury, Delphine

2017-07-01

Yield is subject to strong genotype-by-environment (G × E) interactions in the field, especially under abiotic constraints such as soil water deficit (drought [D]) and high temperature (heat [H]). Since environmental conditions show strong fluctuations during the whole crop cycle, geneticists usually do not consider environmental measures as quantitative variables but rather as factors in multienvironment analyses. Based on 11 experiments in a field platform with contrasting temperature and soil water deficit, we determined the periods of sensitivity to drought and heat constraints in wheat ( Triticum aestivum ) and determined the average sensitivities for major yield components. G × E interactions were separated into their underlying components, constitutive genotypic effect (G), G × D, G × H, and G × H × D, and were analyzed for two genotypes, highlighting contrasting responses to heat and drought constraints. We then tested the constitutive and responsive behaviors of two strong quantitative trait loci (QTLs) associated previously with yield components. This analysis confirmed the constitutive effect of the chromosome 1B QTL and explained the G × E interaction of the chromosome 3B QTL by a benefit of one allele when temperature rises. In addition to the method itself, which can be applied to other data sets and populations, this study will support the cloning of a major yield QTL on chromosome 3B that is highly dependent on environmental conditions and for which the climatic interaction is now quantified. © 2017 American Society of Plant Biologists. All Rights Reserved.

Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components

NASA Technical Reports Server (NTRS)

Campbell, J. E.

1973-01-01

Studies were made of atypical organisms found in Bacillus subtilis var. niger spore colonies. Efforts were aimed at: (1) determining the heat sensitivity of these atypical white spores treated under dry heat conditions and their influence on the nature of the survival curve, (2) preparing a new spore crop obtained from spore isolates by purification procedures, and (3) comparing spore crops obtained from Cape Kennedy (SSM-10) and Minnesota (Minn. sp. AAEF) with the old Cincinnati and new purified Cincinnati spore crop under dry heat conditions.

Validation and Sensitivity Analysis of a New Atmosphere-Soil-Vegetation Model.

NASA Astrophysics Data System (ADS)

Nagai, Haruyasu

2002-02-01

This paper describes details, validation, and sensitivity analysis of a new atmosphere-soil-vegetation model. The model consists of one-dimensional multilayer submodels for atmosphere, soil, and vegetation and radiation schemes for the transmission of solar and longwave radiations in canopy. The atmosphere submodel solves prognostic equations for horizontal wind components, potential temperature, specific humidity, fog water, and turbulence statistics by using a second-order closure model. The soil submodel calculates the transport of heat, liquid water, and water vapor. The vegetation submodel evaluates the heat and water budget on leaf surface and the downward liquid water flux. The model performance was tested by using measured data of the Cooperative Atmosphere-Surface Exchange Study (CASES). Calculated ground surface fluxes were mainly compared with observations at a winter wheat field, concerning the diurnal variation and change in 32 days of the first CASES field program in 1997, CASES-97. The measured surface fluxes did not satisfy the energy balance, so sensible and latent heat fluxes obtained by the eddy correlation method were corrected. By using options of the solar radiation scheme, which addresses the effect of the direct solar radiation component, calculated albedo agreed well with the observations. Some sensitivity analyses were also done for model settings. Model calculations of surface fluxes and surface temperature were in good agreement with measurements as a whole.

Identifying the dominant thermal controls in a small salmonid-bearing creek with DTS and LDCA

NASA Astrophysics Data System (ADS)

Hatch, C. E.; Boughton, D. A.; Mora, E.

2012-12-01

Temperature has long been used as an indicator of ecosystem health and suitability for aquatic species, particularly in sensitive areas crucial to the persistence of declining fish populations. In addition, the EPA may soon implement TMDLs for stream temperatures throughout the U.S. Typically, stream temperature surveys have long duration but only at point locations, limiting the precision of efforts to predict stream temperatures or understand broader climate linkages. Specifically, single temperature loggers give no insight into the spatial heterogeneity of thermal conditions often exploited by biota. Distributed Temperature Sensing (DTS) provides temperature data at high spatial and temporal resolution up to 5-km in length, allowing for detailed assessment of a creek's heat budget. Rather than calculating a detailed energy balance from a single site or using a statistical approach, here we describe a hybrid method that uses Least Dependent Component Analysis (LDCA) capable of taking advantage of DTS data density in time and space. The method identifies distinct thermal components in the stream's heat budget, using only temperature data and an algorithm based on mutual information that "unmixes" signals in the temperature data. These signals can be interpreted as sets of heat-flux elements sharing coordinated (non-independent) dynamics, both simplifying the number of heat budget components as well as the number thermally forcing stream temperatures. Comparing these components to meteorological data and fluvial system structure allowed us to relate the groups back to causal heating and cooling mechanisms, which can be tested directly with targeted heat-budget studies. We applied this method to a small, arid-land creek, and found that a minimum of three distinct components were necessary to describe the thermal heterogeneity of a 1-km reach. We could also estimate a spatial response profile of each component, yielding insight into possible links between stream geomorphology and function. This method shows promise to aid with siting and defining detailed heat-budget studies, determining the dimensionality of heat budgets in natural streams, and more broadly for associating thermal components to fluvial structure and processes.

The Effect of Core Configuration on Thermal Barrier Thermal Performance

NASA Technical Reports Server (NTRS)

DeMange, Jeffrey J.; Bott, Robert H.; Druesedow, Anne S.

2015-01-01

Thermal barriers and seals are integral components in the thermal protection systems (TPS) of nearly all aerospace vehicles. They are used to minimize heat transfer through interfaces and gaps and protect underlying temperature-sensitive components. The core insulation has a significant impact on both the thermal and mechanical properties of compliant thermal barriers. Proper selection of an appropriate core configuration to mitigate conductive, convective and radiative heat transfer through the thermal barrier is challenging. Additionally, optimization of the thermal barrier for thermal performance may have counteracting effects on mechanical performance. Experimental evaluations have been conducted to better understand the effect of insulation density on permeability and leakage performance, which can significantly impact the resistance to convective heat transfer. The effect of core density on mechanical performance was also previously investigated and will be reviewed. Simple thermal models were also developed to determine the impact of various core parameters on downstream temperatures. An extended understanding of these factors can improve the ability to design and implement these critical TPS components.

Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics.

PubMed

Wang, Xiaoli; Xu, Chenxi; Cai, Xiaofeng; Wang, Quanhua; Dai, Shaojun

2017-10-20

Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP)-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO₂ exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.

A Heat Vulnerability Index: Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity for Santiago de Chile.

PubMed

Inostroza, Luis; Palme, Massimo; de la Barrera, Francisco

2016-01-01

Climate change will worsen the high levels of urban vulnerability in Latin American cities due to specific environmental stressors. Some impacts of climate change, such as high temperatures in urban environments, have not yet been addressed through adaptation strategies, which are based on poorly supported data. These impacts remain outside the scope of urban planning. New spatially explicit approaches that identify highly vulnerable urban areas and include specific adaptation requirements are needed in current urban planning practices to cope with heat hazards. In this paper, a heat vulnerability index is proposed for Santiago, Chile. The index was created using a GIS-based spatial information system and was constructed from spatially explicit indexes for exposure, sensitivity and adaptive capacity levels derived from remote sensing data and socio-economic information assessed via principal component analysis (PCA). The objective of this study is to determine the levels of heat vulnerability at local scales by providing insights into these indexes at the intra city scale. The results reveal a spatial pattern of heat vulnerability with strong variations among individual spatial indexes. While exposure and adaptive capacities depict a clear spatial pattern, sensitivity follows a complex spatial distribution. These conditions change when examining PCA results, showing that sensitivity is more robust than exposure and adaptive capacity. These indexes can be used both for urban planning purposes and for proposing specific policies and measures that can help minimize heat hazards in highly dynamic urban areas. The proposed methodology can be applied to other Latin American cities to support policy making.

A Heat Vulnerability Index: Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity for Santiago de Chile

PubMed Central

Palme, Massimo; de la Barrera, Francisco

2016-01-01

Climate change will worsen the high levels of urban vulnerability in Latin American cities due to specific environmental stressors. Some impacts of climate change, such as high temperatures in urban environments, have not yet been addressed through adaptation strategies, which are based on poorly supported data. These impacts remain outside the scope of urban planning. New spatially explicit approaches that identify highly vulnerable urban areas and include specific adaptation requirements are needed in current urban planning practices to cope with heat hazards. In this paper, a heat vulnerability index is proposed for Santiago, Chile. The index was created using a GIS-based spatial information system and was constructed from spatially explicit indexes for exposure, sensitivity and adaptive capacity levels derived from remote sensing data and socio-economic information assessed via principal component analysis (PCA). The objective of this study is to determine the levels of heat vulnerability at local scales by providing insights into these indexes at the intra city scale. The results reveal a spatial pattern of heat vulnerability with strong variations among individual spatial indexes. While exposure and adaptive capacities depict a clear spatial pattern, sensitivity follows a complex spatial distribution. These conditions change when examining PCA results, showing that sensitivity is more robust than exposure and adaptive capacity. These indexes can be used both for urban planning purposes and for proposing specific policies and measures that can help minimize heat hazards in highly dynamic urban areas. The proposed methodology can be applied to other Latin American cities to support policy making. PMID:27606592

Strategies and Approaches to TPS Design

NASA Technical Reports Server (NTRS)

Kolodziej, Paul

2005-01-01

Thermal protection systems (TPS) insulate planetary probes and Earth re-entry vehicles from the aerothermal heating experienced during hypersonic deceleration to the planet s surface. The systems are typically designed with some additional capability to compensate for both variations in the TPS material and for uncertainties in the heating environment. This additional capability, or robustness, also provides a surge capability for operating under abnormal severe conditions for a short period of time, and for unexpected events, such as meteoroid impact damage, that would detract from the nominal performance. Strategies and approaches to developing robust designs must also minimize mass because an extra kilogram of TPS displaces one kilogram of payload. Because aircraft structures must be optimized for minimum mass, reliability-based design approaches for mechanical components exist that minimize mass. Adapting these existing approaches to TPS component design takes advantage of the extensive work, knowledge, and experience from nearly fifty years of reliability-based design of mechanical components. A Non-Dimensional Load Interference (NDLI) method for calculating the thermal reliability of TPS components is presented in this lecture and applied to several examples. A sensitivity analysis from an existing numerical simulation of a carbon phenolic TPS provides insight into the effects of the various design parameters, and is used to demonstrate how sensitivity analysis may be used with NDLI to develop reliability-based designs of TPS components.

A global model for steady state and transient S.I. engine heat transfer studies

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

Bohac, S.V.; Assanis, D.N.; Baker, D.M.

1996-09-01

A global, systems-level model which characterizes the thermal behavior of internal combustion engines is described in this paper. Based on resistor-capacitor thermal networks, either steady-state or transient thermal simulations can be performed. A two-zone, quasi-dimensional spark-ignition engine simulation is used to determine in-cylinder gas temperature and convection coefficients. Engine heat fluxes and component temperatures can subsequently be predicted from specification of general engine dimensions, materials, and operating conditions. Emphasis has been placed on minimizing the number of model inputs and keeping them as simple as possible to make the model practical and useful as an early design tool. The successmore » of the global model depends on properly scaling the general engine inputs to accurately model engine heat flow paths across families of engine designs. The development and validation of suitable, scalable submodels is described in detail in this paper. Simulation sub-models and overall system predictions are validated with data from two spark ignition engines. Several sensitivity studies are performed to determine the most significant heat transfer paths within the engine and exhaust system. Overall, it has been shown that the model is a powerful tool in predicting steady-state heat rejection and component temperatures, as well as transient component temperatures.« less

Mechanism study of biopolymer hair as a coupled thermo-water responsive smart material

NASA Astrophysics Data System (ADS)

Xiao, Xueliang; Zhou, Hongtao; Qian, Kun

2017-03-01

Animal hairs existing broadly in nature are found to be effectively responsive to stimuli of heat and water in sequence for shape deformation and recovery, namely, coupled shape memory function (CSMF). In the paper, the ability of thermo-water sensitive CSMF was first time investigated for animal hairs, the structural and molecular networks for net-points and switches were therefrom identified. Experimentally, animal hair manifested a high ability of shape fixation in thermal processing and good shape recovery by water stimulus. Characterizations of two stimuli (heating and hydration) were performed systematically on hair’s deformation, recovery, viscoelasticity and chemical components (crystalline phase, key bonds inamorphous area). The variations of related chemical components in molecular networks were also explored. A hybrid structural network model was thereafter proposed to interpret the thermo-water sensitive CSMF of hair. This study of two-sequential-stimuli CSMF is original and inspired to explore more complex functions of other smart natural materials and expected to make much smarter synthetic polymers.

Status of FAA Studies in Thermal Acoustics

NASA Astrophysics Data System (ADS)

Lively, John; Ouyang, Zhong; Brasche, Lisa; Holland, Steve; Eisenmann, David; Bantel, Tom; Hassan, Waled

2008-02-01

As with many aerospace applications, commercial jet engine components are operated in demanding environments, often at extreme temperature and stress conditions. The predominant used surface inspection method used on these components is fluorescent penetrant inspection. Research has been ongoing for a number of years on a new technology using a short burst of low frequency (˜20 KHz) ultrasound to "heat up" cracks and make them visible in the infrared range. The basic premise of the Thermal Acoustic method is to use an energy source with recent efforts using an ultrasonic horn originally intended for use in ultrasonic welding to excite the component. The energy source causes an increase in local heating, which is detectable with infrared cameras typically used in Thermographic inspection. While considerable research is underway, additional information on the sensitivity and applicability of this technique to engine components and alloys is needed prior to widespread use in the aviation industry. The purpose of this program is to provide additional data to determine applicability of this method to engine components.

Energy Factor Analysis for Gas Heat Pump Water Heaters

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

Gluesenkamp, Kyle R

2016-01-01

Gas heat pump water heaters (HPWHs) can improve water heating efficiency with zero GWP and zero ODP working fluids. The energy factor (EF) of a gas HPWH is sensitive to several factors. In this work, expressions are derived for EF of gas HPWHs, as a function of heat pump cycle COP, tank heat losses, burner efficiency, electrical draw, and effectiveness of supplemental heat exchangers. The expressions are used to investigate the sensitivity of EF to each parameter. EF is evaluated on a site energy basis (as used by the US DOE for rating water heater EF), and a primary energy-basismore » energy factor (PEF) is also defined and included. Typical ranges of values for the six parameters are given. For gas HPWHs, using typical ranges for component performance, EF will be 59 80% of the heat pump cycle thermal COP (for example, a COP of 1.60 may result in an EF of 0.94 1.28). Most of the reduction in COP is due to burner efficiency and tank heat losses. Gas-fired HPWHs are theoretically be capable of an EF of up to 1.7 (PEF of 1.6); while an EF of 1.1 1.3 (PEF of 1.0 1.1) is expected from an early market entry.« less

Ultrasensitive molecular detection using thermal conductance of a hydrophobic gold-water interface.

PubMed

Green, Andrew J; Alaulamie, Arwa A; Baral, Susil; Richardson, Hugh H

2013-09-11

The thermal conductance from a hydrophobic gold aqueous interface is measured with increasing solute concentration. A small amount of aqueous solute molecules (1 solute molecule in 550 water molecules) dramatically increases the heat dissipation into the surrounding liquid. This result is consistent with a thermal conductance that is limited by an interface interaction where minority aqueous components significantly alter the surface properties and heat transport through the interface. The increase in heat dissipation can be used to make an extremely sensitive molecular detector that can be scaled to give single molecule detection without amplification or utilizing fluorescence labels.

Thermal control on the lunar surface

NASA Technical Reports Server (NTRS)

Walker, Sherry T.; Alexander, Reginald A.; Tucker, Stephen P.

1995-01-01

For a mission to the Moon which lasts more than a few days, thermal control is a challenging problem because of the Moon's wide temperature swings and long day and night periods. During the lunar day it is difficult to reject heat temperatures low enough to be comfortable for either humans or electronic components, while excessive heat loss can damage unprotected equipment at night. Fluid systems can readily be designed to operate at either the hot or cold temperature extreme but it is more difficult to accomodate both extermes within the same system. Special consideration should be given to sensitive systems, such as optics and humans, and systems that generate large amounts of waste heat, such as lunar bases or manufacturing facilities. Passive thermal control systems such as covers, shades and optical coatings can be used to mitigate the temperature swings experienced by components. For more precise thermal control active systems such as heaters or heat pumps are required although they require more power than passive systems.

Experimental assessment of advanced Stirling component concepts

NASA Technical Reports Server (NTRS)

Ziph, B.

1985-01-01

The results of an experimental assessment of some advanced Stirling engine component concepts are presented. High performance piston rings, reciprocating oil scrapers and heat pipes with getters and with mechanical couplings were tested. The tests yielded the following results: (1) Bonded, split, pumping piston rings, in preliminary testing, proved a promising concept, exhibiting low leakage and friction losses. Solid piston rings proved impractical in view of their sensitivity to the operating temperature; (2) A babbit oil scraper in a compliant housing performed well in atmospheric endurance testing. In pressurized tests the scraper did not perform well as a containment seal. The latter tests suggest modifications which may adapt Ti successfully to that application; and (3) Heat pipe endurance tests indicated the adequacy of simple, inexpensive fabrication and filling procedures. Getters were provided to increase the tolerance of the heat pipes to the presence of air and commercially available couplings were demonstrated to be suitable for heat pipe application. In addition to the above tests, the program also included a design effort for a split shaft applicable to a swashplate driven engine with a pressurized crank-case. The design is aimed, and does accomplish, an increase in component life to more than 10,000 hours.

Membrane permeation process for dehydration of organic liquid mixtures using sulfonated ion-exchange polyalkene membranes

DOEpatents

Cabasso, Israel; Korngold, Emmanuel

1988-01-01

A membrane permeation process for dehydrating a mixture of organic liquids, such as alcohols or close boiling, heat sensitive mixtures. The process comprises causing a component of the mixture to selectively sorb into one side of sulfonated ion-exchange polyalkene (e.g., polyethylene) membranes and selectively diffuse or flow therethrough, and then desorbing the component into a gas or liquid phase on the other side of the membranes.

High-Temperature Insulating Gap Filler

NASA Technical Reports Server (NTRS)

Toombs, Gordon R.; Oyoung, Kevin K.; Stevens, Everett G.

1991-01-01

New inorganic, ceramic filler for gaps between refractory ceramic tiles offers high resistance to heat and erosion. Consists of ceramic-fiber fabric precoated with silica and further coated with silica containing small amount of silicon carbide powder to increase thermal emittance. Developed as replacement for organic filler used on thermal-protection system of Space Shuttle. Promises to serve for many missions and to reduce cost and delay of refurbishing aerospace craft. Used as sealing material in furnaces or as heat shield for sensitive components in automobiles, aircraft, and home appliances.

Growth from spores of Clostridium perfringens in the presence of sodium nitrite.

PubMed

Labbe, R G; Duncan, C L

1970-02-01

The method by which sodium nitrite may act to prevent germination or outgrowth, or both, of heat-injured spores in canned cured meats was investigated by using Clostridium perfringens spores. Four possible mechanisms were tested: (i) prevention of germination of the heat-injured spores, (ii) prior combination with a component in a complex medium to prevent germination of heat-injured spores, (iii) inhibition of outgrowth of heat-injured spores, and (iv) induction of germination (which would render the spore susceptible to thermal inactivation). Only the third mechanism was effective with the entire spore population when levels of sodium nitrite commercially acceptable in canned cured meats were used. Concentrations of 0.02 and 0.01% prevented outgrowth of heat-sensitive and heat-resistant spores, respectively. Nitrite-induced germination occurred with higher sodium nitrite concentrations.

Self-regulating proportionally controlled heating apparatus and technique

NASA Technical Reports Server (NTRS)

Strange, M. G. (Inventor)

1975-01-01

A self-regulating proportionally controlled heating apparatus and technique is provided wherein a single electrical resistance heating element having a temperature coefficient of resistance serves simultaneously as a heater and temperature sensor. The heating element is current-driven and the voltage drop across the heating element is monitored and a component extracted which is attributable to a change in actual temperature of the heating element from a desired reference temperature, so as to produce a resulting error signal. The error signal is utilized to control the level of the heater drive current and the actual heater temperature in a direction to reduce the noted temperature difference. The continuous nature of the process for deriving the error signal feedback information results in true proportional control of the heating element without the necessity for current-switching which may interfere with nearby sensitive circuits, and with no cyclical variation in the controlled temperature.

Ultra-low power operation of self-heated, suspended carbon nanotube gas sensors

NASA Astrophysics Data System (ADS)

Chikkadi, Kiran; Muoth, Matthias; Maiwald, Verena; Roman, Cosmin; Hierold, Christofer

2013-11-01

We present a suspended carbon nanotube gas sensor that senses NO2 at ambient temperature and recovers from gas exposure at an extremely low power of 2.9 μW by exploiting the self-heating effect for accelerated gas desorption. The recovery time of 10 min is two orders of magnitude faster than non-heated recovery at ambient temperature. This overcomes an important bottleneck for the practical application of carbon nanotube gas sensors. Furthermore, the method is easy to implement in sensor systems and requires no additional components, paving the way for ultra-low power, compact, and highly sensitive gas sensors.

Structural Integration of Sensors/Actuators by Laser Beam Melting for Tailored Smart Components

NASA Astrophysics Data System (ADS)

Töppel, Thomas; Lausch, Holger; Brand, Michael; Hensel, Eric; Arnold, Michael; Rotsch, Christian

2018-03-01

Laser beam melting (LBM), an additive laser powder bed fusion technology, enables the structural integration of temperature-sensitive sensors and actuators in complex monolithic metallic structures. The objective is to embed a functional component inside a metal part without losing its functionality by overheating. The first part of this paper addresses the development of a new process chain for bonded embedding of temperature-sensitive sensor/actuator systems by LBM. These systems are modularly built and coated by a multi-material/multi-layer thermal protection system of ceramic and metallic compounds. The characteristic of low global heat input in LBM is utilized for the functional embedding. In the second part, the specific functional design and optimization for tailored smart components with embedded functionalities are addressed. Numerical and experimental validated results are demonstrated on a smart femoral hip stem.

A New Approach for Coupled GCM Sensitivity Studies

NASA Astrophysics Data System (ADS)

Kirtman, B. P.; Duane, G. S.

2011-12-01

A new multi-model approach for coupled GCM sensitivity studies is presented. The purpose of the sensitivity experiments is to understand why two different coupled models have such large differences in their respective climate simulations. In the application presented here, the differences between the coupled models using the Center for Ocean-Land-Atmosphere Studies (COLA) and the National Center for Atmospheric Research (NCAR) atmospheric general circulation models (AGCMs) are examined. The intent is to isolate which component of the air-sea fluxes is most responsible for the differences between the coupled models and for the errors in their respective coupled simulations. The procedure is to simultaneously couple the two different atmospheric component models to a single ocean general circulation model (OGCM), in this case the Modular Ocean Model (MOM) developed at the Geophysical Fluid Dynamics Laboratory (GFDL). Each atmospheric component model experiences the same SST produced by the OGCM, but the OGCM is simultaneously coupled to both AGCMs using a cross coupling strategy. In the first experiment, the OGCM is coupled to the heat and fresh water flux from the NCAR AGCM (Community Atmospheric Model; CAM) and the momentum flux from the COLA AGCM. Both AGCMs feel the same SST. In the second experiment, the OGCM is coupled to the heat and fresh water flux from the COLA AGCM and the momentum flux from the CAM AGCM. Again, both atmospheric component models experience the same SST. By comparing these two experimental simulations with control simulations where only one AGCM is used, it is possible to argue which of the flux components are most responsible for the differences in the simulations and their respective errors. Based on these sensitivity experiments we conclude that the tropical ocean warm bias in the COLA coupled model is due to errors in the heat flux, and that the erroneous westward shift in the tropical Pacific cold tongue minimum in the NCAR model is due errors in the momentum flux. All the coupled simulations presented here have warm biases along the eastern boundary of the tropical oceans suggesting that the problem is common to both AGCMs. In terms of interannual variability in the tropical Pacific, the CAM momentum flux is responsible for the erroneous westward extension of the sea surface temperature anomalies (SSTA) and errors in the COLA momentum flux cause the erroneous eastward migration of the El Niño-Southern Oscillation (ENSO) events. These conclusions depend on assuming that the error due to the OGCM can be neglected.

Sensory focusing versus distraction and pain: moderating effects of anxiety sensitivity in males and females.

PubMed

Thompson, Trevor; Keogh, Edmund; French, Christopher C

2011-08-01

Although previous research has examined whether the relative effects of distraction and sensory focusing on pain are dependent upon anxiety sensitivity, such research has concentrated primarily on females. Given the increasing emergence of sex differences in pain processing, the current study aimed to examine whether any influence of anxiety sensitivity on coping effectiveness differs for males and females. The sample consisted of 76 healthy adults (41 males and 35 females), all of whom received distraction and sensory-focusing instructions and underwent noxious thermal testing (cold and heat). Results showed that anxiety sensitivity was positively associated with the emotional qualities of cold pain, and that males exhibited significantly greater heat pain tolerance than females. In addition, within males, a significant coping × anxiety sensitivity effect was found for cold tolerance, with distraction superior to sensory focusing only when anxiety sensitivity was high. In females, however, distraction was a superior strategy irrespective of anxiety sensitivity. This study highlights the importance of considering anxiety sensitivity and sex when examining the relative effectiveness of attentional pain coping strategies. This finding may be potentially beneficial to clinicians considering pain management interventions that include a cognitive or attentional component. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

Automatic analysis with thermometric detection.

PubMed

McLean, W R; Penketh, G E

1968-11-01

The construction of a cell and associated Wheatstone bridge detector circuitry is described for a thermometric detector suitable for attachment to a Technicon Autoanalyzer. The detector produces a d.c. mV signal linearly proportional to the concentration (0.005-0.1M) of the thermally reactive component in the sample stream when it is mixed in the cell with the reagent stream. The influence of various pertinent parameters such as ambient temperature, thermistor voltage, heats of reaction and sensitivity are discussed together with interference effects arising through chemistry, ionic strength effects and heat of dilution.

Porous Ceramic Cures at Moderate Temperatures, Is Good Heat Insulator

NASA Technical Reports Server (NTRS)

Eubanks, Alfred G.; Hunkeler, Ronald E.

1965-01-01

The problem: To develop a foamed-in-place refractory material that would provide good thermal insulation, mechanical support, and vibration shielding for enclosed objects at temperatures up to 30000 F. The preparation of conventional foamed refractory materials required long curing times (as much as 48 hours) and high temperatures (at least 700 F), rendering such materials unusable for in-place potting of heat-sensitive components. The solution: A foamed ceramic material that has the requisite thermal insulation and strength, and also displays other properties that suggest a wide range of applications.

Influence of drought and heat stress, applied independently or in combination during seed development, on qualitative and quantitative aspects of seeds of lentil (Lens culinaris Medikus) genotypes, differing in drought sensitivity.

PubMed

Sehgal, Akanksha; Sita, Kumari; Bhandari, Kalpna; Kumar, Shiv; Kumar, Jitendra; Vara Prasad, P V; Siddique, Kadambot H M; Nayyar, Harsh

2018-05-09

Terminal droughts, along with high temperatures, are becoming more frequent to strongly influence the seed development in cool-season pulses like lentil. In the present study, the lentil plants growing outdoors under natural environment were subjected to following treatments at the time of seed filling till maturity: (a) 28/23 °C day/night temperature as controls; (b) drought stressed, plants maintained at 50% field capacity, under the same growth conditions as in a; (c) heat stressed, 33/28 °C day/night temperature, under the same growth conditions as in a; and (d) drought + heat stressed, plants at 50% field capacity, 33/28 °C day/night temperature, under the same growth conditions as in (a). Both heat and drought resulted in marked reduction in the rate and duration of seed filling to decrease the final seed size; drought resulted in more damage than heat stress; combined stresses accentuated the damage to seed starch, storage proteins and their fractions, minerals, and several amino acids. Comparison of a drought-tolerant and a drought-sensitive genotype indicated the former type showed significantly less damage to various components of seeds, under drought as well as heat stress suggesting a cross tolerance, which was linked to its (drought tolerant) better capacity to retain more water in leaves and hence more photo-assimilation ability, compared with drought-sensitive genotype. © 2018 John Wiley & Sons Ltd.

Laser beam soldering of micro-optical components

NASA Astrophysics Data System (ADS)

Eberhardt, R.

2003-05-01

MOTIVATION Ongoing miniaturisation and higher requirements within optical assemblies and the processing of temperature sensitive components demands for innovative selective joining techniques. So far adhesive bonding has primarily been used to assemble and adjust hybrid micro optical systems. However, the properties of the organic polymers used for the adhesives limit the application of these systems. In fields of telecommunication and lithography, an enhancement of existing joining techniques is necessary to improve properties like humidity resistance, laserstability, UV-stability, thermal cycle reliability and life time reliability. Against this background laser beam soldering of optical components is a reasonable joining technology alternative. Properties like: - time and area restricted energy input - energy input can be controlled by the process temperature - direct and indirect heating of the components is possible - no mechanical contact between joining tool and components give good conditions to meet the requirements on a joining technology for sensitive optical components. Additionally to the laser soldering head, for the assembly of optical components it is necessary to include positioning units to adjust the position of the components with high accuracy before joining. Furthermore, suitable measurement methods to characterize the soldered assemblies (for instance in terms of position tolerances) need to be developed.

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

NASA Technical Reports Server (NTRS)

Pantano, David R.; Dottore, Frank; Tobery, E. Wayne; Geng, Steven M.; Schreiber, Jeffrey G.; Palko, Joseph L.

2005-01-01

An advantage of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used for a number of beneficial purposes including: maintaining electronic components within a controlled temperature range, warming propulsion tanks and mobility actuators, and maintaining liquid propellants above their freezing temperature. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated large quantities of waste heat due to the low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-Watt Stirling Radioisotope Generator (SRG110) will have higher conversion efficiencies, thereby rejecting less waste heat at a lower temperature and may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of 6 to 7 percent, reject their waste heat at the relatively high heat rejection temperature of 200 C. This is an advantage when rejecting heat to space; however, transferring heat to the internal spacecraft components requires a large and heavy radiator heat exchanger. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation of the RTG. The SRG110, with an efficiency around 22 percent and 50 C nominal housing surface temperature, can readily transfer the available waste heat directly via heat pipes, thermal straps, or fluid loops. The lower temperatures associated with the SRG110 avoid the chances of overheating other scientific components, eliminating the need for thermal shields. This provides the spacecraft designers more flexibility when locating the generator for a specific mission. A common misconception with high-efficiency systems is that there is not enough waste heat for spacecraft thermal management. This paper will dispel this misconception and investigate the use of a high-efficiency SRG110 for spacecraft thermal management and outline potential methods of waste heat utilization in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander). The advantages associated with the SRG110 as they relate to ease of assembly, less complex interfaces, and overall mass savings for a spacecraft will be highlighted.

Active heat exchange system development for latent heat thermal energy storage

NASA Technical Reports Server (NTRS)

Lefrois, R. T.; Knowles, G. R.; Mathur, A. K.; Budimir, J.

1979-01-01

Active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250 C to 350 C, using the heat of fusion of molten salts for storing thermal energy are described. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. The heat exchange concepts were sized and compared for 6.5 MPa/281 C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out.

Effects of different temperature treatments on biological ice nuclei in snow samples

NASA Astrophysics Data System (ADS)

Hara, Kazutaka; Maki, Teruya; Kakikawa, Makiko; Kobayashi, Fumihisa; Matsuki, Atsushi

2016-09-01

The heat tolerance of biological ice nucleation activity (INA) depends on their types. Different temperature treatments may cause varying degrees of inactivation on biological ice nuclei (IN) in precipitation samples. In this study, we measured IN concentration and bacterial INA in snow samples using a drop freezing assay, and compared the results for unheated snow and snow treated at 40 °C and 90 °C. At a measured temperature of -7 °C, the concentration of IN in untreated snow was 100-570 L-1, whereas the concentration in snow treated at 40 °C and 90 °C was 31-270 L-1 and 2.5-14 L-1, respectively. In the present study, heat sensitive IN inactivated by heating at 40 °C were predominant, and ranged 23-78% of IN at -7 °C compared with untreated samples. Ice nucleation active Pseudomonas strains were also isolated from the snow samples, and heating at 40 °C and 90 °C inactivated these microorganisms. Consequently, different temperature treatments induced varying degrees of inactivation on IN in snow samples. Differences in the concentration of IN across a range of treatment temperatures might reflect the abundance of different heat sensitive biological IN components.

A Numerical Study of Atmospheric Perturbations Induced by Heat From a Wildland Fire: Sensitivity to Vertical Canopy Structure and Heat Source Strength

NASA Astrophysics Data System (ADS)

Kiefer, Michael T.; Zhong, Shiyuan; Heilman, Warren E.; Charney, Joseph J.; Bian, Xindi

2018-03-01

An improved understanding of atmospheric perturbations within and above a forest during a wildland fire has relevance to many aspects of wildland fires including fire spread, smoke transport and dispersion, and tree mortality. In this study, the ARPS-CANOPY model, a version of the Advanced Regional Prediction System (ARPS) model with a canopy parameterization, is utilized in a series of idealized numerical experiments to investigate the influence of vertical canopy structure on the atmospheric response to a stationary sensible heat flux at the ground ("fire heat flux"), broadly consistent in magnitude with the sensible heat flux from a low-intensity surface fire. Five vertical canopy structures are combined with five fire heat flux magnitudes to yield a matrix of 25 simulations. Analyses of the fire-heat-flux-perturbed u component of the wind, vertical velocity, kinetic energy, and temperature show that the spatial pattern and magnitude of the perturbations are sensitive to vertical canopy structure. Both vertical velocity and kinetic energy exhibit an increasing trend with increasing fire heat flux that is stronger for cases with some amount of overstory vegetation than cases with exclusively understory vegetation. A weaker trend in cases with exclusively understory vegetation indicates a damping of the atmospheric response to the sensible heat from a surface fire when vegetation is most concentrated near the surface. More generally, the results presented in this study suggest that canopy morphology should be considered when applying the results of a fire-atmosphere interaction study conducted in one type of forest to other forests with different canopy structures.

Development of a component design tool for metal hydride heat pumps

NASA Astrophysics Data System (ADS)

Waters, Essene L.

Given current demands for more efficient and environmentally friendly energy sources, hydrogen based energy systems are an increasingly popular field of interest. Within the field, metal hydrides have become a prominent focus of research due to their large hydrogen storage capacity and relative system simplicity and safety. Metal hydride heat pumps constitute one such application, in which heat and hydrogen are transferred to and from metal hydrides. While a significant amount of work has been done to study such systems, the scope of materials selection has been quite limited. Typical studies compare only a few metal hydride materials and provide limited justification for the choice of those few. In this work, a metal hydride component design tool has been developed to enable the targeted down-selection of an extensive database of metal hydrides to identify the most promising materials for use in metal hydride thermal systems. The material database contains over 300 metal hydrides with various physical and thermodynamic properties included for each material. Sub-models for equilibrium pressure, thermophysical data, and default properties are used to predict the behavior of each material within the given system. For a given thermal system, this tool can be used to identify optimal materials out of over 100,000 possible hydride combinations. The selection tool described herein has been applied to a stationary combined heat and power system containing a high-temperature proton exchange membrane (PEM) fuel cell, a hot water tank, and two metal hydride beds used as a heat pump. A variety of factors can be used to select materials including efficiency, maximum and minimum system pressures, pressure difference, coefficient of performance (COP), and COP sensitivity. The targeted down-selection of metal hydrides for this system focuses on the system's COP for each potential pair. The values of COP and COP sensitivity have been used to identify pairs of highest interest for use in this application. The metal hydride component design tool developed in this work selects between metal hydride materials on an unprecedented scale. It can be easily applied to other hydrogen-based thermal systems, making it a powerful and versatile tool.

Ceramics for engines

NASA Technical Reports Server (NTRS)

Kiser, James D.; Levine, Stanley R.; Dicarlo, James A.

1987-01-01

Structural ceramics were under nearly continuous development for various heat engine applications since the early 1970s. These efforts were sustained by the properties that ceramics offer in the areas of high-temperature strength, environmental resistance, and low density and the large benefits in system efficiency and performance that can result. The promise of ceramics was not realized because their brittle nature results in high sensitivity to microscopic flaws and catastrophic fracture behavior. This translated into low reliability for ceramic components and thus limited their application in engines. For structural ceramics to successfully make inroads into the terrestrial heat engine market requires further advances in low cost, net shape fabrication of high reliability components, and improvements in properties such as toughness, and strength. These advances will lead to very limited use of ceramics in noncritical applications in aerospace engines. For critical aerospace applications, an additional requirement is that the components display markedly improved toughness and noncatastrophic or graceful fracture. Thus the major emphasis is on fiber-reinforced ceramics.

Global excitation of wave phenomena in a dissipative multiconstituent medium. III - Response characteristics for different sources in the earth's thermosphere

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.; Varosi, F.; Herrero, F. A.

1987-01-01

A linear trasnfer function model of the earth's thermosphere which includes the electric field momentum source is used to study the differences in the response characteristics for Joule heating and momentum coupling in the thermosphere. It is found that, for Joule/particle heating, the temperature and density perturbations contain a relatively large trapped component which has the property of a low-pass filter, with slow decay after the source is turned off. The decay time is sensitive to the altitude of energy deposition and is significantly reduced as the source peak moves from 125 to 150 km. For electric field momentum coupling, the trapped components in the temperature and density perturbations are relatively small. In the curl field of the velocity, however, the trapped component dominates, but compared with the temperature and density its decay time is much shorter. Outside the source region the form of excitation is of secondary importance for the generation of the various propagating gravity wave modes.

Genetic component of sensitivity to heat stress for nonreturn rate of Brazilian Holstein cattle.

PubMed

Santana, M L; Bignardi, A B; Stefani, G; El Faro, L

2017-08-01

The objectives of the present study were: 1) to investigate variation in the genetic component of heat stress for nonreturn rate at 56 days after first artificial insemination (NR56); 2) to identify and characterize the genotype by environment interaction (G × E) due to heat stress for NR56 of Brazilian Holstein cattle. A linear random regression model (reaction norm model) was applied to 51,748 NR56 records of 28,595 heifers and multiparous cows. The decline in NR56 due to heat stress was more pronounced in milking cows compared to heifers. The age of females at first artificial insemination and temperature-humidity index (THI) exerted an important influence on the genetic parameters of NR56. Several evidence of G × E on NR56 were found as the high slope/intercept ratio and frequent intersection of reaction norms. Additionally, the genetic correlation between NR56 at opposite extremes of the THI scale reached estimates below zero, indicating that few of the same genes are responsible for NR56 under conditions of thermoneutrality and heat stress. The genetic evaluation and selection for NR56 in Holstein cattle reared under (sub)tropical conditions should therefore take into consideration the genetic variation on age at insemination and G × E due to heat stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Use of a fluidized bed for the thermal and chemicothermal treatment of metals

NASA Astrophysics Data System (ADS)

Varygin, N. N.; Ol'shanov, E. Ya.

1971-06-01

An investigation of the heat processes in a fluidized bed shows that this unit has a high heating rate and cooling rate, and allows direct control in the process of heat treatment; chemicothermal processing is speeded up 3-5 times. Examples of experimental-industrial and industrial use show the advantages of using the fluidized bed for rapid nonoxidative heating for thermal processing and pressure processing, and also for replacing expensive salt and metal baths. The use of the fluidized bed is promising for heating temperature-sensitive aluminum and other nonferrous alloys, and for heat processing refractory metals, and alloys [45], etc. It is desirable to use the fluidized bed as the cooling medium to achieve optimum cooling with reduced stresses in components of especially complex configuration. It would be promising to use the fluidized bed for carrying out chemicothermal processing and for creating new processes (including surface saturation with rare metals), especially with the application of electrical, and possibly strong magnetic, fields.

Evaluation of the Components of the North Carolina Syndromic Surveillance System Heat Syndrome Case Definition.

PubMed

Harduar Morano, Laurel; Waller, Anna E

To improve heat-related illness surveillance, we evaluated and refined North Carolina's heat syndrome case definition. We analyzed North Carolina emergency department (ED) visits during 2012-2014. We evaluated the current heat syndrome case definition (ie, keywords in chief complaint/triage notes or International Classification of Diseases, Ninth Revision, Clinical Modification [ ICD-9-CM] codes) and additional heat-related inclusion and exclusion keywords. We calculated the positive predictive value and sensitivity of keyword-identified ED visits and manually reviewed ED visits to identify true positives and false positives. The current heat syndrome case definition identified 8928 ED visits; additional inclusion keywords identified another 598 ED visits. Of 4006 keyword-identified ED visits, 3216 (80.3%) were captured by 4 phrases: "heat ex" (n = 1674, 41.8%), "overheat" (n = 646, 16.1%), "too hot" (n = 594, 14.8%), and "heatstroke" (n = 302, 7.5%). Among the 267 ED visits identified by keyword only, a burn diagnosis or the following keywords resulted in a false-positive rate >95%: "burn," "grease," "liquid," "oil," "radiator," "antifreeze," "hot tub," "hot spring," and "sauna." After applying the revised inclusion and exclusion criteria, we identified 9132 heat-related ED visits: 2157 by keyword only, 5493 by ICD-9-CM code only, and 1482 by both (sensitivity = 27.0%, positive predictive value = 40.7%). Cases identified by keywords were strongly correlated with cases identified by ICD-9-CM codes (rho = .94, P < .001). Revising the heat syndrome case definition through the use of additional inclusion and exclusion criteria substantially improved the accuracy of the surveillance system. Other jurisdictions may benefit from refining their heat syndrome case definition.

Aggregate blood pressure responses to serial dietary sodium and potassium intervention: defining responses using independent component analysis.

PubMed

Chen, Gengsheng; de las Fuentes, Lisa; Gu, Chi C; He, Jiang; Gu, Dongfeng; Kelly, Tanika; Hixson, James; Jacquish, Cashell; Rao, D C; Rice, Treva K

2015-06-20

Hypertension is a complex trait that often co-occurs with other conditions such as obesity and is affected by genetic and environmental factors. Aggregate indices such as principal components among these variables and their responses to environmental interventions may represent novel information that is potentially useful for genetic studies. In this study of families participating in the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) Study, blood pressure (BP) responses to dietary sodium interventions are explored. Independent component analysis (ICA) was applied to 20 variables indexing obesity and BP measured at baseline and during low sodium, high sodium and high sodium plus potassium dietary intervention periods. A "heat map" protocol that classifies subjects based on risk for hypertension is used to interpret the extracted components. ICA and heat map suggest four components best describe the data: (1) systolic hypertension, (2) general hypertension, (3) response to sodium intervention and (4) obesity. The largest heritabilities are for the systolic (64%) and general hypertension (56%) components. There is a pattern of higher heritability for the component response to intervention (40-42%) as compared to those for the traditional intervention responses computed as delta scores (24%-40%). In summary, the present study provides intermediate phenotypes that are heritable. Using these derived components may prove useful in gene discovery applications.

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

NASA Technical Reports Server (NTRS)

Pantano, David R.; Dottore, Frank; Geng, Steven M.; Schrieber, Jeffrey G.; Tobery, E. Wayne; Palko, Joseph L.

2005-01-01

One of the advantages of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used to maintain electronic components within a controlled temperature range, to warm propulsion tanks and mobility actuators, and to gasify liquid propellants. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated a very large quantity of waste heat due to the relatively low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-watt Stirling Radioisotope Generator (SRG110) will have much higher conversion efficiencies than their predecessors and therefore may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of approx. 6 to 7% and 200 C housing surface temperatures, would need to use large and heavy radiator heat exchangers to transfer the waste heat to the internal spacecraft components. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation by using the heat exchangers or additional shields. The SRG110, with an efficiency around 22% and 50 C nominal housing surface temperature, can use the available waste heat more efficiently by more direct heat transfer methods such as heat pipes, thermal straps, or fluid loops. The lower temperatures allow the SRG110 much more flexibility to the spacecraft designers in configuring the generator without concern of overheating nearby scientific instruments, thereby eliminating the need for thermal shields. This paper will investigate using a high efficiency SRG110 for spacecraft thermal management and outline potential methods in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander) to illustrate the advantages with regard to ease of assembly, less complex interfaces, and overall mass savings.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps

NASA Astrophysics Data System (ADS)

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A.

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps.

PubMed

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Polarity-defective mutants of Aspergillus nidulans.

PubMed

Osherov, N; Mathew, J; May, G S

2000-12-01

We have identified two polarity-defective (pod) mutants in Aspergillus nidulans from a collection of heat-sensitive lethal mutants. At restrictive temperature, these mutants are capable of nuclear division but are unable to establish polar hyphal growth. We cloned the two pod genes by complementation of their heat-sensitive lethal phenotypes. The libraries used to clone the pod genes are under the control of the bidirectional niaD and niiA promoters. Complementation of the pod mutants is dependent on growth on inducing medium. We show that rescue of the heat-sensitive phenotype on inducing media is independent of the orientation of the gene relative to the niaD or niiA promoters, demonstrating that the intergenic region between the niaD and the niiA genes functions as an orientation-independent enhancer and repressor that is capable of functioning over long distances. The products of the podG and the podH genes were identified as homologues of the alpha subunit of yeast mitochondrial phenylalanyl--tRNA synthetase and transcription factor IIF interacting component of the CTD phosphatase. Neither of these gene products would have been predicted to produce a pod mutant phenotype based on studies of cellular polarity mutants in other organisms. The implications of these results are discussed. Copyright 2000 Academic Press.

Cyclic high temperature heat storage using borehole heat exchangers

NASA Astrophysics Data System (ADS)

Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

2016-04-01

The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for varying storage cycle times, operating conditions and storage set-ups. A sensitivity analysis shows that storage efficiency strongly depends on the number of BHEs composing the storage site and the cycle time. Using a half-yearly cycle of heat injection and extraction with the maximum possible rates shows that the fraction of recovered heat increases with the number of storage cycles used, as initial losses due to heat conduction become smaller. Also, overall recovery rates of 70 to 80% are possible in the set-ups investigated. Temperature distribution in the geological heat storage site is most sensitive to the thermal conductivity of both borehole grouting and storage formation, while storage efficiency is dominated by the thermal conductivity of the storage formation. For the large cycle times of 6 months each used, heat capacity is less sensitive than the heat conductivity. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

Sampling and analysis of airborne resin acids and solvent-soluble material derived from heated colophony (rosin) flux: a method to quantify exposure to sensitizing compounds liberated during electronics soldering.

PubMed

Smith, P A; Son, P S; Callaghan, P M; Jederberg, W W; Kuhlmann, K; Still, K R

1996-07-17

Components of colophony (rosin) resin acids are sensitizers through dermal and pulmonary exposure to heated and unheated material. Significant work in the literature identifies specific resin acids and their oxidation products as sensitizers. Pulmonary exposure to colophony sensitizers has been estimated indirectly through formaldehyde exposure. To assess pulmonary sensitization from airborne resin acids, direct measurement is desired, as the degree to which aldehyde exposure correlates with that of resin acids during colophony heating is undefined. Any analytical method proposed should be applicable to a range of compounds and should also identify specific compounds present in a breathing zone sample. This work adapts OSHA Sampling and Analytical Method 58, which is designed to provide airborne concentration data for coal tar pitch volatile solids by air filtration through a glass fiber filter, solvent extraction of the filter, and gravimetric analysis of the non-volatile extract residue. In addition to data regarding total soluble material captured, a portion of the extract may be subjected to compound-specific analysis. Levels of soluble solids found during personal breathing zone sampling during electronics soldering in a Naval Aviation Depot ranged from below the "reliable quantitation limit" reported in the method to 7.98 mg/m3. Colophony-spiked filters analyzed in accordance with the method (modified) produced a limit of detection for total solvent-soluble colophony solids of 10 micrograms/filter. High performance liquid chromatography was used to identify abietic acid present in a breathing zone sample.

Comparison of the heat stress induced variations in DNA methylation between heat-tolerant and heat-sensitive rapeseed seedlings

PubMed Central

Gao, Guizhen; Li, Jun; Li, Hao; Li, Feng; Xu, Kun; Yan, Guixin; Chen, Biyun; Qiao, Jiangwei; Wu, Xiaoming

2014-01-01

DNA methylation is responsive to various biotic and abiotic stresses. Heat stress is a serious threat to crop growth and development worldwide. Heat stress results in an array of morphological, physiological and biochemical changes in plants. The relationship between DNA methylation and heat stress in crops is relatively unknown. We investigated the differences in methylation levels and changes in the cytosine methylation patterns in seedlings of two rapeseed genotypes (heat-sensitive and heat-tolerant) under heat stress. Our results revealed that the methylation levels were different between a heat-tolerant genotype and a heat-sensitive one under control conditions. Under heat treatment, methylation increased more in the heat-sensitive genotype than in the heat-tolerant genotype. More DNA demethylation events occurred in the heat-tolerant genotype, while more DNA methylation occurred in the heat-sensitive genotype. A large and diverse set of genes were affected by heat stress via cytosine methylation changes, suggesting that these genes likely play important roles in the response and adaption to heat stress in Brassica napus L. This study indicated that the changes in DNA methylation differed between heat-tolerant and heat-sensitive genotypes of B. napus in response to heat stress, which further illuminates the molecular mechanisms of the adaption to heat stress in B. napus. PMID:24987298

Quantitative sensory testing response patterns to capsaicin- and ultraviolet-B–induced local skin hypersensitization in healthy subjects: a machine-learned analysis

PubMed Central

Lötsch, Jörn; Geisslinger, Gerd; Heinemann, Sarah; Lerch, Florian; Oertel, Bruno G.; Ultsch, Alfred

2018-01-01

Abstract The comprehensive assessment of pain-related human phenotypes requires combinations of nociceptive measures that produce complex high-dimensional data, posing challenges to bioinformatic analysis. In this study, we assessed established experimental models of heat hyperalgesia of the skin, consisting of local ultraviolet-B (UV-B) irradiation or capsaicin application, in 82 healthy subjects using a variety of noxious stimuli. We extended the original heat stimulation by applying cold and mechanical stimuli and assessing the hypersensitization effects with a clinically established quantitative sensory testing (QST) battery (German Research Network on Neuropathic Pain). This study provided a 246 × 10-sized data matrix (82 subjects assessed at baseline, following UV-B application, and following capsaicin application) with respect to 10 QST parameters, which we analyzed using machine-learning techniques. We observed statistically significant effects of the hypersensitization treatments in 9 different QST parameters. Supervised machine-learned analysis implemented as random forests followed by ABC analysis pointed to heat pain thresholds as the most relevantly affected QST parameter. However, decision tree analysis indicated that UV-B additionally modulated sensitivity to cold. Unsupervised machine-learning techniques, implemented as emergent self-organizing maps, hinted at subgroups responding to topical application of capsaicin. The distinction among subgroups was based on sensitivity to pressure pain, which could be attributed to sex differences, with women being more sensitive than men. Thus, while UV-B and capsaicin share a major component of heat pain sensitization, they differ in their effects on QST parameter patterns in healthy subjects, suggesting a lack of redundancy between these models. PMID:28700537

Exploring the Relationship Between Octane Sensitivity and Heat-of-Vaporization

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

Sluder, C. Scott; Szybist, James P.; McCormick, Robert L.

2016-04-05

The latent heat-of-vaporization (HoV) of blends of biofuel and hydrocarbon components into gasolines has recently experienced expanded interest because of the potential for increased HoV to increase fuel knock resistance in direct-injection (DI) engines. Several studies have been conducted, with some studies identifying an additional anti-knock benefit from HoV and others failing to arrive at the same conclusion. Consideration of these studies holistically shows that they can be grouped according to the level of fuel octane sensitivity variation within their fuel matrices. When comparing fuels of different octane sensitivity significant additional anti-knock benefits associated with HoV are sometimes observed. Studiesmore » that fix the octane sensitivity find that HoV does not produce additional anti-knock benefit. New studies were performed at ORNL and NREL to further investigate the relationship between HoV and octane sensitivity. Three fuels were formulated for the ORNL study with matched RON and octane sensitivity, but with differing HoV. Experiments with these fuels in a 1.6-liter GTDI engine showed that the fuels exhibited very similar combustion phasing under knock-limited spark advance (KLSA) conditions. Fuels having a range of RON, octane sensitivity, and HoV were tested at NREL in a single-cylinder GDI engine under conditions where octane sensitivity has little effect on knock resistance. KLSA was found to be well correlated with RON. These results reinforce the concept that HoV anti-knock effects can be viewed as a contributor to octane sensitivity. From this viewpoint, HoV effects manifest themselves as increases in octane sensitivity.« less

Identification of the Allergenic Ingredients in Reduning Injection by Ultrafiltration and High-Performance Liquid Chromatography.

PubMed

Wang, Fang; Li, Cun-yu; Zheng, Yun-feng; Li, Hong-yang; Xiao, Wei; Peng, Guo-ping

2016-01-01

Reduning injection is a traditional Chinese medicine injection which has multiple functions such as clearing heat, dispelling wind, and detoxification. Although Reduning injection was widely utilized, reports of its allergenicity emerged one after another. However, there is little research on its allergenic substances. The aim of this study is to evaluate the sensitization of Reduning injection and explore the underlying cause of the anaphylactic reaction. The main ingredients in Reduning injection were analyzed before and after ultrafiltration. Ultrafiltrate Reduning injection, unfiltered Reduning injection, egg albumin, Tween-80, and nine effective components in Reduning injection were utilized to sensitize guinea pigs. The serum 5-hydroxytryptamine level was used to assess the sensitization effect of Reduning injection. We found a significant decrease in Tween-80 content comparing to other components in the injection after ultrafiltration. Unfiltered Reduning injection, Tween-80, chlorogenic acid, and cryptochlorogenin acid caused remarkable anaphylactoid reaction on guinea pigs while ultrafiltration Reduning resulted in a significantly lower degree of sensitization. Our results suggest that ultrafiltration could significantly reduce the sensitization of Reduning injection, which is likely due to the decrease of Tween-80. We also conjectured that the form of chlorogenic acid and cryptochlorogenin acid within the complex solution mixture may also affect the sensitizing effect.

Influence of different heat treatment methods of titania film on performance of DSSCs

NASA Astrophysics Data System (ADS)

More, Venumadhav; Mokurala, Krishna; Bhargava, Parag

2018-04-01

Titania mesoporous film is a key component of dye-sensitized solar cells (DSSCs) as it transfers electrons from dye molecule to external circuit through the transparent conducting oxide (TCO). Interparticle connectivity, porosity and cracks in the titania films play an important role in determining the performance of DSSCs. The heating schedule with respect to the repetitive coating to build up titania film thickness impacts the titania film characteristics. In the present study, experiments were designed to carry out heat treatments with expectation of improving connectivity and healing cracks. Repetitive screen printing was carried out with either heat treatment after each print step (multiple sintering) or the heat treatment was carried out just once after the desired thickness had been attained (single-step sintering). Interconnectivity of the titania particles in the sintered titania film was analyzed by impedance spectroscopy and nanoindentation. Titania films sintered by MS showed better performance in terms of higher efficiency for the corresponding DSSCs than those prepared using titania films sintered by SS.

Effect of Heat Stress on Reproduction in Dairy Cows: Insights into the Cellular and Molecular Responses of the Oocyte.

PubMed

Roth, Zvi

2017-02-08

Among the components of the female reproductive tract, the ovarian pool of follicles and their enclosed oocytes are highly sensitive to hyperthermia. Heat-induced alterations in small antral follicles can be expressed later as compromised maturation and developmental capacity of the ovulating oocyte. This review summarizes the most up-to-date information on the effects of heat stress on the oocyte with an emphasis on unclear points and open questions, some of which might involve new research directions, for instance, whether preantral follicles are heat resistant. The review focuses on the follicle-enclosed oocytes, provides new insights into the cellular and molecular responses of the oocyte to elevated temperature, points out the role of the follicle microenvironment, and discusses some mechanisms that might underlie oocyte impairment. Mechanisms include nuclear and cytoplasmic maturation, mitochondrial function, apoptotic pathways, and oxidative stress. Understanding the mechanism by which heat stress compromises fertility might enable development of new strategies to mitigate its effects.

Preliminary Analysis of a Fully Solid State Magnetocaloric Refrigeration

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

Abdelaziz, Omar

Magnetocaloric refrigeration is an alternative refrigeration technology with significant potential energy savings compared to conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. In this paper, we propose an alternative mechanism for heat transfer between the AMR and the heat source/sink. High-conductivity moving rods/sheets (e.g. copper, brass, iron, graphite, aluminum or composite structures from these) are utilized instead of heat transfer fluid significantly enhancing the heatmore » transfer rate hence cooling/heating capacity. A one-dimensional model is developed to study the solid state AMR. In this model, the heat exchange between the solid-solid interfaces is modeled via a contact conductance, which depends on the interface apparent pressure, material hardness, thermal conductivity, surface roughness, surface slope between the interfaces, and material filled in the gap between the interfaces. Due to the tremendous impact of the heat exchange on the AMR cycle performance, a sensitivity analysis is conducted employing a response surface method, in which the apparent pressure, effective surface roughness and grease thermal conductivity are the uncertainty factors. COP and refrigeration capacity are presented as the response in the sensitivity analysis to reveal the important factors influencing the fully solid state AMR and optimize the solid state AMR efficiency. The performances of fully solid state AMR and traditional AMR are also compared and discussed in present work. The results of this study will provide general guidelines for designing high performance solid state AMR systems.« less

Infrared thermography with non-uniform heat flux boundary conditions on the rotor endwall of an axial turbine

NASA Astrophysics Data System (ADS)

Lazzi Gazzini, S.; Schädler, R.; Kalfas, A. I.; Abhari, R. S.

2017-02-01

It is technically challenging to measure heat fluxes on the rotating components of gas turbines, yet accurate knowledge of local heat loads under engine-representative conditions is crucial for ensuring the reliability of the designs. In this work, quantitative image processing tools were developed to perform fast and accurate infrared thermography measurements on 3D-shaped film-heaters directly deposited on the turbine endwalls. The newly developed image processing method and instrumentation were used to measure the heat load on the rotor endwalls of an axial turbine. A step-transient heat flux calibration technique is applied to measure the heat flux generated locally by the film heater, thus eliminating the need for a rigorously iso-energetic boundary condition. On-board electronics installed on the rotor record the temperature readings of RTDs installed in the substrate below the heaters in order to evaluate the conductive losses in the solid. Full maps of heat transfer coefficient and adiabatic wall temperature are produced for two different operating conditions, demonstrating the sensitivity of the technique to local flow features and variations in heat transfer due to Reynolds number effect.

Efficient numerical simulation of heat storage in subsurface georeservoirs

NASA Astrophysics Data System (ADS)

Boockmeyer, A.; Bauer, S.

2015-12-01

The transition of the German energy market towards renewable energy sources, e.g. wind or solar power, requires energy storage technologies to compensate for their fluctuating production. Large amounts of energy could be stored in georeservoirs such as porous formations in the subsurface. One possibility here is to store heat with high temperatures of up to 90°C through borehole heat exchangers (BHEs) since more than 80 % of the total energy consumption in German households are used for heating and hot water supply. Within the ANGUS+ project potential environmental impacts of such heat storages are assessed and quantified. Numerical simulations are performed to predict storage capacities, storage cycle times, and induced effects. For simulation of these highly dynamic storage sites, detailed high-resolution models are required. We set up a model that accounts for all components of the BHE and verified it using experimental data. The model ensures accurate simulation results but also leads to large numerical meshes and thus high simulation times. In this work, we therefore present a numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly for use in larger scale simulations. The numerical model includes all BHE components and represents the temporal and spatial temperature distribution with an accuracy of less than 2% deviation from the fully discretized model. By changing the BHE geometry and using equivalent parameters, the simulation time is reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. Results of a sensitivity study that quantify the effects of different design and storage formation parameters on temperature distribution and storage efficiency for heat storage using multiple BHEs are then shown. It is found that storage efficiency strongly depends on the number of BHEs composing the storage site, their distance and the cycle time. The temperature distribution is most sensitive to thermal conductivity of both borehole grouting and storage formation while storage efficiency is mainly controlled by the thermal conductivity of the storage formation.

Two part condenser for varying the rate of condensing and related method

DOEpatents

Dobos, James G.

2007-12-11

A heat transfer apparatus, such as a condenser, is provided. The apparatus includes a first component with a first heat transfer element that has first component inlet and outlet ports through which a first fluid may pass. A second component is also included and likewise has a second heat transfer element with second component inlet and outlet ports to pass a second fluid. The first component has a body that can receive a third fluid for heat transfer with the first heat transfer element. The first and second components are releasably attachable with one another so that when attached both the first and second heat transfer elements effect heat transfer with the third fluid. Attachment and removal of the first and second components allows for the heat transfer rate of the apparatus to be varied. An associated method is also provided.

Thermally determining flow and/or heat load distribution in parallel paths

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

Chainer, Timothy J.; Iyengar, Madhusudan K.; Parida, Pritish R.

A method including obtaining calibration data for at least one sub-component in a heat transfer assembly, wherein the calibration data comprises at least one indication of coolant flow rate through the sub-component for a given surface temperature delta of the sub-component and a given heat load into said sub-component, determining a measured heat load into the sub-component, determining a measured surface temperature delta of the sub-component, and determining a coolant flow distribution in a first flow path comprising the sub-component from the calibration data according to the measured heat load and the measured surface temperature delta of the sub-component.

Thermally determining flow and/or heat load distribution in parallel paths

DOEpatents

Chainer, Timothy J.; Iyengar, Madhusudan K.; Parida, Pritish R.

2016-12-13

A method including obtaining calibration data for at least one sub-component in a heat transfer assembly, wherein the calibration data comprises at least one indication of coolant flow rate through the sub-component for a given surface temperature delta of the sub-component and a given heat load into said sub-component, determining a measured heat load into the sub-component, determining a measured surface temperature delta of the sub-component, and determining a coolant flow distribution in a first flow path comprising the sub-component from the calibration data according to the measured heat load and the measured surface temperature delta of the sub-component.

Printable, flexible and stretchable diamond for thermal management

DOEpatents

Rogers, John A; Kim, Tae Ho; Choi, Won Mook; Kim, Dae Hyeong; Meitl, Matthew; Menard, Etienne; Carlisle, John

2013-06-25

Various heat-sinked components and methods of making heat-sinked components are disclosed where diamond in thermal contact with one or more heat-generating components are capable of dissipating heat, thereby providing thermally-regulated components. Thermally conductive diamond is provided in patterns capable of providing efficient and maximum heat transfer away from components that may be susceptible to damage by elevated temperatures. The devices and methods are used to cool flexible electronics, integrated circuits and other complex electronics that tend to generate significant heat. Also provided are methods of making printable diamond patterns that can be used in a range of devices and device components.

In vitro investigation of heat transfer phenomenon in human immature teeth.

PubMed

Talebi, Maryam; Moghimi, Sahar; Shafagh, Mina; Kalani, Hadi; Mazhari, Fatemeh

2014-01-01

Background and aims. Heat generated within tooth during clinical dentistry can cause thermally induced damage to hard and soft components of the tooth (enamel, dentin and pulp). Geometrical characteristics of immature teeth are different from those of mature teeth. The purpose of this experimental and theoretical study was to investigate thermal changes in immature permanent teeth during the use of LED light-curing units (LCU). Materials and methods. This study was performed on the second mandibular premolars. This experimental investiga-tion was carried out for recording temperature variations of different sites of tooth and two dimensional finite element models were used for heat transfer phenomenon in immature teeth. Sensitivity analysis and local tests were included in the model validation phase. Results. Overall, thermal stimulation for 30 seconds with a low-intensity LED LCU increased the temperature from 28°C to 38°C in IIT (intact immature tooth) and PIT (cavity-prepared immature tooth). When a high-intensity LED LCU was used, tooth temperature increased from 28°C to 48°C. The results of the experimental tests and mathematical modeling illustrated that using LED LCU on immature teeth did not have any detrimental effect on the pulp temperature. Conclusion. Using LED LCU in immature teeth had no effect on pulp temperature in this study. Sensitivity analysis showed that variations of heat conductivity might affect heat transfer in immature teeth; therefore, further studies are required to determine thermal conductivity of immature teeth.

Highly sensitive current sensor utilizing CrNi-wire supported microfiber coils

NASA Astrophysics Data System (ADS)

Xie, Xiaodong; Li, Jie; Sun, Li-Peng; Jin, Long; Guan, Bai-ou

2013-09-01

High current sensitivity is obtained based on a microfiber that is wrapping around a chrome-nickel (CrNi) wire. Due to the strong heating effect of the CrNi wire with the flowing electric current, the mode index and the loop length of microfiber are changed, resulting in the shift of resonant wavelength. The measured current responsivity is as high as 220.65nm/A2, which is in two or three magnitude orders than the previously-obtained ones. We study the influence of component size to the structure performance, which is useful for future applications of current sensing or tuning devices.

Passive heat-transfer means for nuclear reactors. [LMFBR

DOEpatents

Burelbach, J.P.

1982-06-10

An improved passive cooling arrangement is disclosed for maintaining adjacent or related components of a nuclear reactor within specified temperature differences. Specifically, heat pipes are operatively interposed between the components, with the vaporizing section of the heat pipe proximate the hot component operable to cool it and the primary condensing section of the heat pipe proximate the other and cooler component operable to heat it. Each heat pipe further has a secondary condensing section that is located outwardly beyond the reactor confinement and in a secondary heat sink, such as air ambient the containment, that is cooler than the other reactor component. By having many such heat pipes, an emergency passive cooling system is defined that is operative without electrical power.

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

PubMed

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

2015-03-01

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

Hybrid solar collector using nonimaging optics and photovoltaic components

NASA Astrophysics Data System (ADS)

Winston, Roland; Yablonovitch, Eli; Jiang, Lun; Widyolar, Bennett K.; Abdelhamid, Mahmoud; Scranton, Gregg; Cygan, David; Kozlov, Alexandr

2015-08-01

The project team of University of California at Merced (UC-M), Gas Technology Institute, and Dr. Eli Yablonovitch of University of California at Berkeley developed a novel hybrid concentrated solar photovoltaic thermal (PV/T) collector using nonimaging optics and world record single-junction Gallium arsenide (GaAs) PV components integrated with particle laden gas as thermal transfer and storage media, to simultaneously generate electricity and high temperature dispatchable heat. The collector transforms a parabolic trough, commonly used in CSP plants, into an integrated spectrum-splitting device. This places a spectrum-sensitive topping element on a secondary reflector that is registered to the thermal collection loop. The secondary reflector transmits higher energy photons for PV topping while diverting the remaining lower energy photons to the thermal media, achieving temperatures of around 400°C even under partial utilization of the solar spectrum. The collector uses the spectral selectivity property of Gallium arsenide (GaAs) cells to maximize the exergy output of the system, resulting in an estimated exergy efficiency of 48%. The thermal media is composed of fine particles of high melting point material in an inert gas that increases heat transfer and effectively stores excess heat in hot particles for later on-demand use.

Impact of the hard-coded parameters on the hydrologic fluxes of the land surface model Noah-MP

NASA Astrophysics Data System (ADS)

Cuntz, Matthias; Mai, Juliane; Samaniego, Luis; Clark, Martyn; Wulfmeyer, Volker; Attinger, Sabine; Thober, Stephan

2016-04-01

Land surface models incorporate a large number of processes, described by physical, chemical and empirical equations. The process descriptions contain a number of parameters that can be soil or plant type dependent and are typically read from tabulated input files. Land surface models may have, however, process descriptions that contain fixed, hard-coded numbers in the computer code, which are not identified as model parameters. Here we searched for hard-coded parameters in the computer code of the land surface model Noah with multiple process options (Noah-MP) to assess the importance of the fixed values on restricting the model's agility during parameter estimation. We found 139 hard-coded values in all Noah-MP process options, which are mostly spatially constant values. This is in addition to the 71 standard parameters of Noah-MP, which mostly get distributed spatially by given vegetation and soil input maps. We performed a Sobol' global sensitivity analysis of Noah-MP to variations of the standard and hard-coded parameters for a specific set of process options. 42 standard parameters and 75 hard-coded parameters were active with the chosen process options. The sensitivities of the hydrologic output fluxes latent heat and total runoff as well as their component fluxes were evaluated. These sensitivities were evaluated at twelve catchments of the Eastern United States with very different hydro-meteorological regimes. Noah-MP's hydrologic output fluxes are sensitive to two thirds of its standard parameters. The most sensitive parameter is, however, a hard-coded value in the formulation of soil surface resistance for evaporation, which proved to be oversensitive in other land surface models as well. Surface runoff is sensitive to almost all hard-coded parameters of the snow processes and the meteorological inputs. These parameter sensitivities diminish in total runoff. Assessing these parameters in model calibration would require detailed snow observations or the calculation of hydrologic signatures of the runoff data. Latent heat and total runoff exhibit very similar sensitivities towards standard and hard-coded parameters in Noah-MP because of their tight coupling via the water balance. It should therefore be comparable to calibrate Noah-MP either against latent heat observations or against river runoff data. Latent heat and total runoff are sensitive to both, plant and soil parameters. Calibrating only a parameter sub-set of only soil parameters, for example, thus limits the ability to derive realistic model parameters. It is thus recommended to include the most sensitive hard-coded model parameters that were exposed in this study when calibrating Noah-MP.

Evaluation of a surface/vegetation parameterization using satellite measurements of surface temperature

NASA Technical Reports Server (NTRS)

Taconet, O.; Carlson, T.; Bernard, R.; Vidal-Madjar, D.

1986-01-01

Ground measurements of surface-sensible heat flux and soil moisture for a wheat-growing area of Beauce in France were compared with the values derived by inverting two boundary layer models with a surface/vegetation formulation using surface temperature measurements made from NOAA-AVHRR. The results indicated that the trends in the surface heat fluxes and soil moisture observed during the 5 days of the field experiment were effectively captured by the inversion method using the remotely measured radiative temperatures and either of the two boundary layer methods, both of which contain nearly identical vegetation parameterizations described by Taconet et al. (1986). The sensitivity of the results to errors in the initial sounding values or measured surface temperature was tested by varying the initial sounding temperature, dewpoint, and wind speed and the measured surface temperature by amounts corresponding to typical measurement error. In general, the vegetation component was more sensitive to error than the bare soil model.

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

Morita, Takahiro; Satoh, Ryosuke; Japan Society for the Promotion of Science, 1-8 Chiyoda-ku, Tokyo 102-8472

Highlights: Black-Right-Pointing-Pointer Stress granules (SGs) as a mechanism of doxorubicin tolerance. Black-Right-Pointing-Pointer We characterize the role of stress granules in doxorubicin tolerance. Black-Right-Pointing-Pointer Deletion of components of SGs enhances doxorubicin sensitivity in fission yeast. Black-Right-Pointing-Pointer Doxorubicin promotes SG formation when combined with heat shock. Black-Right-Pointing-Pointer Doxorubicin regulates stress granule assembly independent of eIF2{alpha} phosphorylation. -- Abstract: Doxorubicin is an anthracycline antibiotic widely used for chemotherapy. Although doxorubicin is effective in the treatment of several cancers, including solid tumors and leukemias, the basis of its mechanism of action is not completely understood. Here, we describe the effects of doxorubicin and itsmore » relationship with stress granules formation in the fission yeast, Schizosaccharomyces pombe. We show that disruption of genes encoding the components of stress granules, including vgl1{sup +}, which encodes a multi-KH type RNA-binding protein, and pab1{sup +}, which encodes a poly(A)-binding protein, resulted in greater sensitivity to doxorubicin than seen in wild-type cells. Disruption of the vgl1{sup +} and pab1{sup +} genes did not confer sensitivity to other anti-cancer drugs such as cisplatin, 5-fluorouracil, and paclitaxel. We also showed that doxorubicin treatment promoted stress granule formation when combined with heat shock. Notably, doxorubicin treatment did not induce hyperphosphorylation of eIF2{alpha}, suggesting that doxorubicin is involved in stress granule assembly independent of eIF2{alpha} phosphorylation. Our results demonstrate the usefulness of fission yeast for elucidating the molecular targets of doxorubicin toxicity and suggest a novel drug-resistance mechanism involving stress granule assembly.« less

Passive heat transfer means for nuclear reactors

DOEpatents

Burelbach, James P.

1984-01-01

An improved passive cooling arrangement is disclosed for maintaining adjacent or related components of a nuclear reactor within specified temperature differences. Specifically, heat pipes are operatively interposed between the components, with the vaporizing section of the heat pipe proximate the hot component operable to cool it and the primary condensing section of the heat pipe proximate the other and cooler component operable to heat it. Each heat pipe further has a secondary condensing section that is located outwardly beyond the reactor confinement and in a secondary heat sink, such as air ambient the containment, that is cooler than the other reactor component. Means such as shrouding normally isolated the secondary condensing section from effective heat transfer with the heat sink, but a sensor responds to overheat conditions of the reactor to open the shrouding, which thereby increases the cooling capacity of the heat pipe. By having many such heat pipes, an emergency passive cooling system is defined that is operative without electrical power.

Use Dependence of Heat Sensitivity of Vanilloid Receptor TRPV2

PubMed Central

Liu, Beiying; Qin, Feng

2016-01-01

Thermal TRP channels mediate temperature transduction and pain sensation. The vanilloid receptor TRPV2 is involved in detection of noxious heat in a subpopulation of high-threshold nociceptors. It also plays a critical role in development of thermal hyperalgesia, but the underlying mechanism remains uncertain. Here we analyze the heat sensitivity of the TRPV2 channel. Heat activation of the channel exhibits strong use dependence. Prior heat activation can profoundly alter its subsequent temperature responsiveness, causing decreases in both temperature activation threshold and slope sensitivity of temperature dependence while accelerating activation time courses. Notably, heat and agonist activations differ in cross use-dependence. Prior heat stimulation can dramatically sensitize agonist responses, but not conversely. Quantitative analyses indicate that the use dependence in heat sensitivity is pertinent to the process of temperature sensing by the channel. The use dependence of TRPV2 reveals that the channel can have a dynamic temperature sensitivity. The temperature sensing structures within the channel have multiple conformations and the temperature activation pathway is separate from the agonist activation pathway. Physiologically, the use dependence of TRPV2 confers nociceptors with a hypersensitivity to heat and thus provides a mechanism for peripheral thermal hyperalgesia. PMID:27074678

Benchmark Data Set for Wheat Growth Models: Field Experiments and AgMIP Multi-Model Simulations.

NASA Technical Reports Server (NTRS)

Asseng, S.; Ewert, F.; Martre, P.; Rosenzweig, C.; Jones, J. W.; Hatfield, J. L.; Ruane, A. C.; Boote, K. J.; Thorburn, P.J.; Rotter, R. P.

2015-01-01

The data set includes a current representative management treatment from detailed, quality-tested sentinel field experiments with wheat from four contrasting environments including Australia, The Netherlands, India and Argentina. Measurements include local daily climate data (solar radiation, maximum and minimum temperature, precipitation, surface wind, dew point temperature, relative humidity, and vapor pressure), soil characteristics, frequent growth, nitrogen in crop and soil, crop and soil water and yield components. Simulations include results from 27 wheat models and a sensitivity analysis with 26 models and 30 years (1981-2010) for each location, for elevated atmospheric CO2 and temperature changes, a heat stress sensitivity analysis at anthesis, and a sensitivity analysis with soil and crop management variations and a Global Climate Model end-century scenario.

Polyploidization mechanisms: temperature environment can induce diploid gamete formation in Rosa sp.

PubMed

Pécrix, Yann; Rallo, Géraldine; Folzer, Hélène; Cigna, Mireille; Gudin, Serge; Le Bris, Manuel

2011-06-01

Polyploidy is an important evolutionary phenomenon but the mechanisms by which polyploidy arises still remain underexplored. There may be an environmental component to polyploidization. This study aimed to clarify how temperature may promote diploid gamete formation considered an essential element for sexual polyploidization. First of all, a detailed cytological analysis of microsporogenesis and microgametogenesis was performed to target precisely the key developmental stages which are the most sensitive to temperature. Then, heat-induced modifications in sporad and pollen characteristics were analysed through an exposition of high temperature gradient. Rosa plants are sensitive to high temperatures with a developmental sensitivity window limited to meiosis. Moreover, the range of efficient temperatures is actually narrow. 36 °C at early meiosis led to a decrease in pollen viability, pollen ectexine defects but especially the appearance of numerous diploid pollen grains. They resulted from dyads or triads mainly formed following heat-induced spindle misorientations in telophase II. A high temperature environment has the potential to increase gamete ploidy level. The high frequencies of diplogametes obtained at some extreme temperatures support the hypothesis that polyploidization events could have occurred in adverse conditions and suggest polyploidization facilitating in a global change context.

Dissection of the components for PIP2 activation and thermosensation in TRP channels

PubMed Central

Brauchi, Sebastian; Orta, Gerardo; Mascayano, Carolina; Salazar, Marcelo; Raddatz, Natalia; Urbina, Hector; Rosenmann, Eduardo; Gonzalez-Nilo, Fernando; Latorre, Ramon

2007-01-01

Phosphatidylinositol 4,5-bisphosphate (PIP2) plays a central role in the activation of several transient receptor potential (TRP) channels. The role of PIP2 on temperature gating of thermoTRP channels has not been explored in detail, and the process of temperature activation is largely unexplained. In this work, we have exchanged different segments of the C-terminal region between cold-sensitive (TRPM8) and heat-sensitive (TRPV1) channels, trying to understand the role of the segment in PIP2 and temperature activation. A chimera in which the proximal part of the C-terminal of TRPV1 replaces an equivalent section of TRPM8 C-terminal is activated by PIP2 and confers the phenotype of heat activation. PIP2, but not temperature sensitivity, disappears when positively charged residues contained in the exchanged region are neutralized. Shortening the exchanged segment to a length of 11 aa produces voltage-dependent and temperature-insensitive channels. Our findings suggest the existence of different activation domains for temperature, PIP2, and voltage. We provide an interpretation for channel–PIP2 interaction using a full-atom molecular model of TRPV1 and PIP2 docking analysis. PMID:17548815

Multi-component assembly casting

DOEpatents

James, Allister W.

2015-10-13

Multi-component vane segment and method for forming the same. Assembly includes: positioning a pre-formed airfoil component (12) and a preformed shroud heat resistant material (18) in a mold, wherein the airfoil component (12) and the shroud heat resistant material (18) each comprises an interlocking feature (24); preheating the mold; introducing molten structural material (46) into the mold; and solidifying the molten structural material such that it interlocks the pre-formed airfoil component (12) with respect to the preformed shroud heat resistant material (18) and is effective to provide structural support for the shroud heat resistant material (18). Surfaces between the airfoil component (12) and the structural material (46), between the airfoil component (12) and the shroud heat resistant material (18), and between the shroud heat resistant material (18) and the structural material (46) are free of metallurgical bonds.

Uncertainty Propagation in Hypersonic Vehicle Aerothermoelastic Analysis

NASA Astrophysics Data System (ADS)

Lamorte, Nicolas Etienne

Hypersonic vehicles face a challenging flight environment. The aerothermoelastic analysis of its components requires numerous simplifying approximations. Identifying and quantifying the effect of uncertainties pushes the limits of the existing deterministic models, and is pursued in this work. An uncertainty quantification framework is used to propagate the effects of identified uncertainties on the stability margins and performance of the different systems considered. First, the aeroelastic stability of a typical section representative of a control surface on a hypersonic vehicle is examined. Variability in the uncoupled natural frequencies of the system is modeled to mimic the effect of aerodynamic heating. Next, the stability of an aerodynamically heated panel representing a component of the skin of a generic hypersonic vehicle is considered. Uncertainty in the location of transition from laminar to turbulent flow and the heat flux prediction is quantified using CFD. In both cases significant reductions of the stability margins are observed. A loosely coupled airframe--integrated scramjet engine is considered next. The elongated body and cowl of the engine flow path are subject to harsh aerothermodynamic loading which causes it to deform. Uncertainty associated with deformation prediction is propagated to the engine performance analysis. The cowl deformation is the main contributor to the sensitivity of the propulsion system performance. Finally, a framework for aerothermoelastic stability boundary calculation for hypersonic vehicles using CFD is developed. The usage of CFD enables one to consider different turbulence conditions, laminar or turbulent, and different models of the air mixture, in particular real gas model which accounts for dissociation of molecules at high temperature. The system is found to be sensitive to turbulence modeling as well as the location of the transition from laminar to turbulent flow. Real gas effects play a minor role in the flight conditions considered. These studies demonstrate the advantages of accounting for uncertainty at an early stage of the analysis. They emphasize the important relation between heat flux modeling, thermal stresses and stability margins of hypersonic vehicles.

Quantitative sensory testing response patterns to capsaicin- and ultraviolet-B-induced local skin hypersensitization in healthy subjects: a machine-learned analysis.

PubMed

Lötsch, Jörn; Geisslinger, Gerd; Heinemann, Sarah; Lerch, Florian; Oertel, Bruno G; Ultsch, Alfred

2017-08-16

The comprehensive assessment of pain-related human phenotypes requires combinations of nociceptive measures that produce complex high-dimensional data, posing challenges to bioinformatic analysis. In this study, we assessed established experimental models of heat hyperalgesia of the skin, consisting of local ultraviolet-B (UV-B) irradiation or capsaicin application, in 82 healthy subjects using a variety of noxious stimuli. We extended the original heat stimulation by applying cold and mechanical stimuli and assessing the hypersensitization effects with a clinically established quantitative sensory testing (QST) battery (German Research Network on Neuropathic Pain). This study provided a 246 × 10-sized data matrix (82 subjects assessed at baseline, following UV-B application, and following capsaicin application) with respect to 10 QST parameters, which we analyzed using machine-learning techniques. We observed statistically significant effects of the hypersensitization treatments in 9 different QST parameters. Supervised machine-learned analysis implemented as random forests followed by ABC analysis pointed to heat pain thresholds as the most relevantly affected QST parameter. However, decision tree analysis indicated that UV-B additionally modulated sensitivity to cold. Unsupervised machine-learning techniques, implemented as emergent self-organizing maps, hinted at subgroups responding to topical application of capsaicin. The distinction among subgroups was based on sensitivity to pressure pain, which could be attributed to sex differences, with women being more sensitive than men. Thus, while UV-B and capsaicin share a major component of heat pain sensitization, they differ in their effects on QST parameter patterns in healthy subjects, suggesting a lack of redundancy between these models.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

The replacement of dry heat in generic reliability assurance requirements for passive optical components

NASA Astrophysics Data System (ADS)

Ren, Xusheng; Qian, Longsheng; Zhang, Guiyan

2005-12-01

According to Generic Reliability Assurance Requirements for Passive Optical Components GR-1221-CORE (Issue 2, January 1999), reliability determination test of different kinds of passive optical components which using in uncontrolled environments is taken. The test condition of High Temperature Storage Test (Dry Test) and Damp Test is in below sheet. Except for humidity condition, all is same. In order to save test time and cost, after a sires of contrast tests, the replacement of Dry Heat is discussed. Controlling the Failure mechanism of dry heat and damp heat of passive optical components, the contrast test of dry heat and damp heat for passive optical components (include DWDM, CWDM, Coupler, Isolator, mini Isolator) is taken. The test result of isolator is listed. Telcordia test not only test the reliability of the passive optical components, but also test the patience of the experimenter. The cost of Telcordia test in money, manpower and material resources, especially in time is heavy burden for the company. After a series of tests, we can find that Damp heat could factually test the reliability of passive optical components, and equipment manufacturer in accord with component manufacture could omit the dry heat test if damp heat test is taken first and passed.

Use Dependence of Heat Sensitivity of Vanilloid Receptor TRPV2.

PubMed

Liu, Beiying; Qin, Feng

2016-04-12

Thermal TRP channels mediate temperature transduction and pain sensation. The vanilloid receptor TRPV2 is involved in detection of noxious heat in a subpopulation of high-threshold nociceptors. It also plays a critical role in development of thermal hyperalgesia, but the underlying mechanism remains uncertain. Here we analyze the heat sensitivity of the TRPV2 channel. Heat activation of the channel exhibits strong use dependence. Prior heat activation can profoundly alter its subsequent temperature responsiveness, causing decreases in both temperature activation threshold and slope sensitivity of temperature dependence while accelerating activation time courses. Notably, heat and agonist activations differ in cross use-dependence. Prior heat stimulation can dramatically sensitize agonist responses, but not conversely. Quantitative analyses indicate that the use dependence in heat sensitivity is pertinent to the process of temperature sensing by the channel. The use dependence of TRPV2 reveals that the channel can have a dynamic temperature sensitivity. The temperature sensing structures within the channel have multiple conformations and the temperature activation pathway is separate from the agonist activation pathway. Physiologically, the use dependence of TRPV2 confers nociceptors with a hypersensitivity to heat and thus provides a mechanism for peripheral thermal hyperalgesia. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

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

Zhang, Xiaoyong, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies.more » Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.« less

Hard X-ray Detectability of Small-Scale Coronal Heating Events

NASA Astrophysics Data System (ADS)

Marsh, A.; Glesener, L.; Klimchuk, J. A.; Bradshaw, S. J.; Smith, D. M.; Hannah, I. G.

2016-12-01

The nanoflare heating theory predicts the ubiquitous presence of hot ( >5 MK) plasma in the solar corona, but evidence for this high-temperature component has been scarce. Current hard x-ray instruments such as RHESSI lack the sensitivity to see the trace amounts of this plasma that are predicted by theoretical models. New hard X-ray instruments that use focusing optics, such as FOXSI (the Focusing Optics X-ray Solar Imager) and NuSTAR (the Nuclear Spectroscopic Telescope Array) can extend the visible parameter space of nanoflare "storms" that create hot plasma. We compare active-region data from FOXSI and NuSTAR with a series of EBTEL hydrodynamic simulations, and constrain nanoflare properties to give good agreement with observations.

Hard X-ray Detectability of Small-Scale Coronal Heating Events

NASA Astrophysics Data System (ADS)

Marsh, Andrew; Glesener, Lindsay; Klimchuk, James A.; Bradshaw, Stephen; Smith, David; Hannah, Iain

2016-05-01

The nanoflare heating theory predicts the ubiquitous presence of hot (~>5 MK) plasma in the solar corona, but evidence for this high-temperature component has been scarce. Current hard x-ray instruments such as RHESSI lack the sensitivity to see the trace amounts of this plasma that are predicted by theoretical models. New hard X-ray instruments that use focusing optics, such as FOXSI (the Focusing Optics X-ray Solar Imager) and NuSTAR (the Nuclear Spectroscopic Telescope Array) can extend the visible parameter space of nanoflare “storms” that create hot plasma. We compare active-region data from FOXSI and NuSTAR with a series of EBTEL hydrodynamic simulations, and constrain nanoflare properties to give good agreement with observations.

High temperature sensitivity is intrinsic to voltage-gated potassium channels

PubMed Central

Yang, Fan; Zheng, Jie

2014-01-01

Temperature-sensitive transient receptor potential (TRP) ion channels are members of the large tetrameric cation channels superfamily but are considered to be uniquely sensitive to heat, which has been presumed to be due to the existence of an unidentified temperature-sensing domain. Here we report that the homologous voltage-gated potassium (Kv) channels also exhibit high temperature sensitivity comparable to that of TRPV1, which is detectable under specific conditions when the voltage sensor is functionally decoupled from the activation gate through either intrinsic mechanisms or mutations. Interestingly, mutations could tune Shaker channel to be either heat-activated or heat-deactivated. Therefore, high temperature sensitivity is intrinsic to both TRP and Kv channels. Our findings suggest important physiological roles of heat-induced variation in Kv channel activities. Mechanistically our findings indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain; instead, non-obligatory allosteric gating permits the intrinsic heat sensitivity to drive channel activation, allowing temperature-sensitive TRP channels to function as polymodal nociceptors. DOI: http://dx.doi.org/10.7554/eLife.03255.001 PMID:25030910

Thermal load leveling during silicon crystal growth from a melt using anisotropic materials

DOEpatents

Carlson, Frederick M.; Helenbrook, Brian T.

2016-10-11

An apparatus for growing a silicon crystal substrate comprising a heat source, an anisotropic thermal load leveling component, a crucible, and a cold plate component is disclosed. The anisotropic thermal load leveling component possesses a high thermal conductivity and may be positioned atop the heat source to be operative to even-out temperature and heat flux variations emanating from the heat source. The crucible may be operative to contain molten silicon in which the top surface of the molten silicon may be defined as a growth interface. The crucible may be substantially surrounded by the anisotropic thermal load leveling component. The cold plate component may be positioned above the crucible to be operative with the anisotropic thermal load leveling component and heat source to maintain a uniform heat flux at the growth surface of the molten silicon.

46 CFR 153.1002 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Special operating requirements for heat sensitive cargoes. 153.1002 Section 153.1002 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... MATERIALS Operations Special Cargo Procedures § 153.1002 Special operating requirements for heat sensitive...

46 CFR 153.1002 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Special operating requirements for heat sensitive cargoes. 153.1002 Section 153.1002 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... MATERIALS Operations Special Cargo Procedures § 153.1002 Special operating requirements for heat sensitive...

46 CFR 153.1002 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Special operating requirements for heat sensitive cargoes. 153.1002 Section 153.1002 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... MATERIALS Operations Special Cargo Procedures § 153.1002 Special operating requirements for heat sensitive...

46 CFR 153.1002 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Special operating requirements for heat sensitive cargoes. 153.1002 Section 153.1002 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... MATERIALS Operations Special Cargo Procedures § 153.1002 Special operating requirements for heat sensitive...

46 CFR 153.1002 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Special operating requirements for heat sensitive cargoes. 153.1002 Section 153.1002 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... MATERIALS Operations Special Cargo Procedures § 153.1002 Special operating requirements for heat sensitive...

Process development and exergy cost sensitivity analysis of a hybrid molten carbonate fuel cell power plant and carbon dioxide capturing process

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Ansarinasab, Hojat; Moftakhari Sharifzadeh, Mohammad Mehdi; Rosen, Marc A.

2017-10-01

An integrated power plant with a net electrical power output of 3.71 × 105 kW is developed and investigated. The electrical efficiency of the process is found to be 60.1%. The process includes three main sub-systems: molten carbonate fuel cell system, heat recovery section and cryogenic carbon dioxide capturing process. Conventional and advanced exergoeconomic methods are used for analyzing the process. Advanced exergoeconomic analysis is a comprehensive evaluation tool which combines an exergetic approach with economic analysis procedures. With this method, investment and exergy destruction costs of the process components are divided into endogenous/exogenous and avoidable/unavoidable parts. Results of the conventional exergoeconomic analyses demonstrate that the combustion chamber has the largest exergy destruction rate (182 MW) and cost rate (13,100 /h). Also, the total process cost rate can be decreased by reducing the cost rate of the fuel cell and improving the efficiency of the combustion chamber and heat recovery steam generator. Based on the total avoidable endogenous cost rate, the priority for modification is the heat recovery steam generator, a compressor and a turbine of the power plant, in rank order. A sensitivity analysis is done to investigate the exergoeconomic factor parameters through changing the effective parameter variations.

Mechanisms of Ocean Heat Uptake

NASA Astrophysics Data System (ADS)

Garuba, Oluwayemi

An important parameter for the climate response to increased greenhouse gases or other radiative forcing is the speed at which heat anomalies propagate downward in the ocean. Ocean heat uptake occurs through passive advection/diffusion of surface heat anomalies and through the redistribution of existing temperature gradients due to circulation changes. Atlantic meridional overturning circulation (AMOC) weakens in a warming climate and this should slow the downward heat advection (compared to a case in which the circulation is unchanged). However, weakening AMOC also causes a deep warming through the redistributive effect, thus increasing the downward rate of heat propagation compared to unchanging circulation. Total heat uptake depends on the combined effect of these two mechanisms. Passive tracers in a perturbed CO2 quadrupling experiments are used to investigate the effect of passive advection and redistribution of temperature anomalies. A new passive tracer formulation is used to separate ocean heat uptake into contributions due to redistribution and passive advection-diffusion of surface heating during an ocean model experiment with abrupt increase in surface temperature. The spatial pattern and mechanisms of each component are examined. With further experiments, the effects of surface wind, salinity and temperature changes in changing circulation and the resulting effect on redistribution in the individual basins are isolated. Analysis of the passive advection and propagation path of the tracer show that the Southern ocean dominates heat uptake, largely through vertical and horizontal diffusion. Vertical diffusion transports the tracer across isopycnals down to about 1000m in 100 years in the Southern ocean. Advection is more important in the subtropical cells and in the Atlantic high latitudes, both with a short time scale of about 20 years. The shallow subtropical cells transport the tracer down to about 500m along isopycnal surfaces, below this vertical diffusion takes over transport in the tropics; in the Atlantic, the MOC transports heat as deep 2000m in about 30 years. Redistributive surface heat uptake alters the total amount surface heat uptake among the basins. Compared to the passive-only heat uptake, which is about the same among the basins, redistribution nearly doubles the surface heat input into the Atlantic but makes smaller increases in the Indian and Pacific oceans for a net global increase of about 25%, in the perturbation experiment with winds unchanged. The passive and redistributive heat uptake components are further distributed among the basins through the global conveyor belt. The Pacific gains twice the surface heat input into it through lateral transport from the other two basins, as a result, the Atlantic and Pacific gain similar amounts of heat even though surface heat input is in the Atlantic is much bigger. Of this heat transport, most of the passive component comes from the Indian and the redistributive component comes from the Atlantic. Different surface forcing perturbation gives different circulation change pattern and as a result yield different redistributive uptake. Ocean heat uptake is more sensitive to wind forcing perturbation than to thermohaline forcing perturbation. About 2% reduction in subtropical cells transport and southern ocean transport, in the wind-change perturbation experiment, resulted in about 10% reduction in the global ocean heat uptake of wind-unchanged experiment. The AMOC weakened by about 35% and resulted in a 25% increase in passive heat uptake in the wind-unchanged experiment. Surface winds weakening reduces heat uptake by warming the reservoir surface temperatures, while MOC weakening increases heat input by a cooling reservoir surface temperatures. Thermohaline forcing perturbation is combination of salinity and temperature perturbations, both weaken the AMOC, however, they have opposite redistributive effects. Ocean surface freshening gives positive redistributive effect, while surface temperature increase gives negative redistributive effect on heat uptake. The salinity effect dominates the redistributive effect for thermohaline perturbation.

Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; Almlie, Jay C.

2010-01-01

A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

Global water cycle

NASA Technical Reports Server (NTRS)

Robertson, Franklin R.; Christy, John R.; Goodman, Steven J.; Miller, Tim L.; Fitzjarrald, Dan; Lapenta, Bill; Wang, Shouping

1991-01-01

The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction.

Synthesizing Aluminum Particles Towards Controlling Electrostatic Discharge Ignition Sensitivity

DTIC Science & Technology

2014-01-01

composite energetic materials, Combust. Flame 160 (May 2013) 2279 2281. [10] J. Granier, M. Pantoya, Laser ignition of nanocomposite thermites , Combust...Reactive sintering: an important component in the combustion of nanocomposite thermites , Combust. Flame 159 (1) (Jan. 2012) 2 15. [12] B. Dikici, M.L...Pantoya, V. Levitas, The effect of pre-heating on flame propa- gation behavior in nanocomposite thermites , Combust. Flame 157 (8) (2010) 1581 1585. E.S. Collins et al. / Journal of Electrostatics 72 (2014) 28 3232

Sensitization by heat treatment of Escherichia coli K-12 cells to hydrophobic antibacterial compounds.

PubMed Central

Tsuchido, T; Takano, M

1988-01-01

The sensitivities of intact and heat-injured cells of Escherichia coli K-12 to several antibacterial compounds were measured by the prolongation of growth delay. Cells exposed to sublethal heat became more sensitive to various hydrophobic compounds, such as medium-chain fatty acids, alkyl esters of p-hydroxybenzoic acid, and some kinds of antibiotics or dyes, than unheated cells; but there was a smaller or no increase in sensitivity to short-chain fatty acids, chloramphenicol, and vancomycin. The destruction by heat of a permeability barrier of the outer membrane may have sensitized the cells to hydrophobic compounds. The sensitization was much lower for a strain defective in lipopolysaccharide, which is important as a barrier against hydrophobic compounds. PMID:3075437

Pain thresholds, supra-threshold pain and lidocaine sensitivity in patients with erythromelalgia, including the I848Tmutation in NaV 1.7.

PubMed

Helås, T; Sagafos, D; Kleggetveit, I P; Quiding, H; Jönsson, B; Segerdahl, M; Zhang, Z; Salter, H; Schmelz, M; Jørum, E

2017-09-01

Nociceptive thresholds and supra-threshold pain ratings as well as their reduction upon local injection with lidocaine were compared between healthy subjects and patients with erythromelalgia (EM). Lidocaine (0.25, 0.50, 1.0 or 10 mg/mL) or placebo (saline) was injected intradermally in non-painful areas of the lower arm, in a randomized, double-blind manner, to test the effect on dynamic and static mechanical sensitivity, mechanical pain sensitivity, thermal thresholds and supra-threshold heat pain sensitivity. Heat pain thresholds and pain ratings to supra-threshold heat stimulation did not differ between EM-patients (n = 27) and controls (n = 25), neither did the dose-response curves for lidocaine. Only the subgroup of EM-patients with mutations in sodium channel subunits Na V 1.7, 1.8 or 1.9 (n = 8) had increased lidocaine sensitivity for supra-threshold heat stimuli, contrasting lower sensitivity to strong mechanical stimuli. This pattern was particularly clear in the two patients carrying the Na V 1.7 I848T mutations in whom lidocaine's hyperalgesic effect on mechanical pain sensitivity contrasted more effective heat analgesia. Heat pain thresholds are not sensitized in EM patients, even in those with gain-of-function mutations in Na V 1.7. Differential lidocaine sensitivity was overt only for noxious stimuli in the supra-threshold range suggesting that sensitized supra-threshold encoding is important for the clinical pain phenotype in EM in addition to lower activation threshold. Intracutaneous lidocaine dose-dependently blocked nociceptive sensations, but we did not identify EM patients with particular high lidocaine sensitivity that could have provided valuable therapeutic guidance. Acute pain thresholds and supra-threshold heat pain in controls and patients with erythromelalgia do not differ and have the same lidocaine sensitivity. Acute heat pain thresholds even in EM patients with the Na V 1.7 I848T mutation are normal and only nociceptor sensitivity to intradermal lidocaine is changed. Only in EM patients with mutations in Na V 1.7, 1.8 or 1.9 supra-threshold heat and mechanical pain shows differential lidocaine sensitivity as compared to controls. © 2017 European Pain Federation - EFIC®.

Bark heat resistance of small trees in Californian mixed conifer forests: Testing some model assumptions

USGS Publications Warehouse

van Mantgem, Phillip J.; Schwartz, Mark

2003-01-01

An essential component to models of fire-caused tree mortality is an assessment of cambial damage. Cambial heat resistance has been traditionally measured in large overstory trees with thick bark, although small trees have thinner bark and thus are more sensitive to fire. We undertook this study to determine if current models of bark heat transfer are applicable to small trees (<20 cm diameter at breast height (dbh)). We performed this work in situ on four common species in the mixed conifer forests of the Sierra Nevada, California.The allometric relationship between bole diameter and bark thickness for each species was linear, even for very small trees (5 cm dbh). Heating experiments demonstrated that bark thickness was the primary determinant of cambial heat resistance. We found only slight, but statistically significant, among species differences in bark thermal properties. Our most significant finding was that small trees were more resistant to heating than expected from commonly used models of bark heat transfer. Our results may differ from those of existing models because we found smaller trees to have a greater proportion of inner bark, which appears to have superior insulating properties compared to outer bark. From a management perspective, growth projections suggest that a 50-year fire-free interval may allow some fire intolerant species to achieve at least some degree of cambial heat resistance in the Sierra Nevada.

Near-chip compliant layer for reducing perimeter stress during assembly process

DOEpatents

Schultz, Mark D.; Takken, Todd E.; Tian, Shurong; Yao, Yuan

2018-03-20

A heat source (single semiconductor chip or group of closely spaced semiconductor chips of similar height) is provided on a first side of a substrate, which substrate has on said first side a support member comprising a compressible material. A heat removal component, oriented at an angle to said heat source, is brought into proximity of said heat source such that said heat removal component contacts said support member prior to contacting said heat source. Said heat removal component is assembled to said heat source such that said support member at least partially absorbs global inequality of force that would otherwise be applied to said heat source, absent said support member comprising said compressible material.

Near-chip compliant layer for reducing perimeter stress during assembly process

DOEpatents

Schultz, Mark D.; Takken, Todd E.; Tian, Shurong; Yao, Yuan

2017-02-14

A heat source (single semiconductor chip or group of closely spaced semiconductor chips of similar height) is provided on a first side of a substrate, which substrate has on said first side a support member comprising a compressible material. A heat removal component, oriented at an angle to said heat source, is brought into proximity of said heat source such that said heat removal component contacts said support member prior to contacting said heat source. Said heat removal component is assembled to said heat source such that said support member at least partially absorbs global inequality of force that would otherwise be applied to said heat source, absent said support member comprising said compressible material.

Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles

NASA Technical Reports Server (NTRS)

Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo

2009-01-01

In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2

46 CFR 151.50-81 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Special operating requirements for heat sensitive cargoes. 151.50-81 Section 151.50-81 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... § 151.50-81 Special operating requirements for heat sensitive cargoes. When table 151.05 refers to this...

46 CFR 151.50-81 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Special operating requirements for heat sensitive cargoes. 151.50-81 Section 151.50-81 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... § 151.50-81 Special operating requirements for heat sensitive cargoes. When table 151.05 refers to this...

46 CFR 151.50-81 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Special operating requirements for heat sensitive cargoes. 151.50-81 Section 151.50-81 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... § 151.50-81 Special operating requirements for heat sensitive cargoes. When table 151.05 refers to this...

46 CFR 151.50-81 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Special operating requirements for heat sensitive cargoes. 151.50-81 Section 151.50-81 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... § 151.50-81 Special operating requirements for heat sensitive cargoes. When table 151.05 refers to this...

46 CFR 151.50-81 - Special operating requirements for heat sensitive cargoes.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Special operating requirements for heat sensitive cargoes. 151.50-81 Section 151.50-81 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... § 151.50-81 Special operating requirements for heat sensitive cargoes. When table 151.05 refers to this...

Identification of heat-sensitive QTL derived from common wild rice (Oryza rufipogon Griff.).

PubMed

Lei, Dongyang; Tan, Lubin; Liu, Fengxia; Chen, Liyun; Sun, Chuanqing

2013-03-01

Understanding the responses of rice plants to heat-stress is a challenging, yet crucial, endeavor. A set of introgression lines was previously developed using an advanced backcrossing strategy that involved the elite indica cultivar Teqing as the recipient and an accession of common wild rice (Oryza rufipongon Griff.) as the donor. In this study, we evaluated the responses of 90 of these previously developed introgression lines to heat stress. Five quantitative trait loci (QTLs) related to heat response were detected. The phenotypic variances explained by these QTLs ranged from 6.83% to 14.63%, and O. rufipogon-derived alleles at one locus reduced sensitivity to heat. A heat-sensitive introgression line, YIL106, was identified and characterized. Genotypic analysis demonstrated that YIL106 contained four introgressed segments derived from O. rufipongon and two QTLs (qHTS1-1 and qHTS3) related to heat response. Physiological tests, including measurements of chlorophyll content, electrolyte leakage, malondialdehyde content, and soluble sugar content, were consistent with the heat sensitivity observed in YIL106. Ultrastructural analysis of YIL106 mesophyll cells showed that they were severely damaged following heat stress. This suggests that modification of the cell membrane system is a primary response to heat stress in plants. Identification and characterization of the heat-sensitive line YIL106 may facilitate the isolation of genes associated with the response of rice plants to heat stress. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Product formulation for ohmic heating: blanching as a pretreatment method to improve uniformity in heating of solid-liquid food mixtures.

PubMed

Sarang, S; Sastry, S K; Gaines, J; Yang, T C S; Dunne, P

2007-06-01

The electrical conductivity of food components is critical to ohmic heating. Food components of different electrical conductivities heat at different rates. While equal electrical conductivities of all phases are desirable, real food products may behave differently. In the present study involving chicken chow mein consisting of a sauce and different solid components, celery, water chestnuts, mushrooms, bean sprouts, and chicken, it was observed that the sauce was more conductive than all solid components over the measured temperature range. To improve heating uniformity, a blanching method was developed to increase the ionic content of the solid components. By blanching different solid components in a highly conductive sauce at 100 degrees C for different lengths of time, it was possible to adjust their conductivity to that of the sauce. Chicken chow mein samples containing blanched particulates were compared with untreated samples with respect to ohmic heating uniformity at 60 Hz up to 140 degrees C. All components of the treated product containing blanched solids heated more uniformly than untreated product. In sensory tests, 3 different formulations of the blanched product showed good quality attributes and overall acceptability, demonstrating the practical feasibility of the blanching protocol.

Modular Cooling Components

NASA Technical Reports Server (NTRS)

Eastman, G. Yale; Dussinger, Peter M.; Hartenstine, John R.

1994-01-01

Three modular heat-transfer components designed for use together or separately. Simple mechanical connections facilitate assembly of these and related heat-transfer components into cooling systems of various configurations, such as to cool laboratory equipment rearranged for different experiments. Components are clamp-on cold plate, cold plate attached to flexible heat pipe, and thermal-bus receptacle. Clamp-on cold plate moved to any convenient location for attachment of equipment cooled by it, then clamped onto thermal bus. Heat from equipment conducted through plate and into coolant. Thermal-bus receptacle integral with thermal bus. Includes part of thermal bus to which clamp-on cold plate attached, plus tapered socket into which condenser end of flexible heat pipe plugged. Thermal-bus receptacle includes heat-pipe wick structure using coolant in bus to enhance transfer of heat from cold plate.

Mounting improves heat-sink contact with beryllia washer

NASA Technical Reports Server (NTRS)

1966-01-01

To conduct heat away from electrical components that must be electrically insulated from a metal heat sink, a metal washer and a coil spring are placed between one end of the electrical component and the beryllia washer mounted on the heat sink. The thermal paths are formed by the component lead and base, the metal and beryllia washers, and the compressed spring.

The CANDELLE experiment for characterization of neutron sensitivity of LiF TLDs

NASA Astrophysics Data System (ADS)

Guillou, M. Le; Billebaud, A.; Gruel, A.; Kessedjian, G.; Méplan, O.; Destouches, C.; Blaise, P.

2018-01-01

As part of the design studies conducted at CEA for future power and research nuclear reactors, the validation of neutron and photon calculation schemes related to nuclear heating prediction are strongly dependent on the implementation of nuclear heating measurements. Such measurements are usually performed in low-power reactors, whose core dimensions are accurately known and where irradiation conditions (power, flux and temperature) are entirely controlled. Due to the very low operating power of such reactors (of the order of 100 W), nuclear heating is assessed by using dosimetry techniques such as thermoluminescent dosimeters (TLDs). However, although they are highly sensitive to gamma radiation, such dosimeters are also, to a lesser extent, sensitive to neutrons. The neutron dose depends strongly on the TLD composition, typically contributing to 10-30% of the total measured dose in a mixed neutron/gamma field. The experimental determination of the neutron correction appears therefore to be crucial to a better interpretation of doses measured in reactor with reduced uncertainties. A promising approach based on the use of two types of LiF TLDs respectively enriched with lithium-6 and lithium-7, precalibrated both in photon and neutron fields, has been recently developed at INFN (Milan, Italy) for medical purposes. The CANDELLE experiment is dedicated to the implementation of a pure neutron field "calibration" of TLDs by using the GENEPI-2 neutron source of LPSC (Grenoble, France). Those irradiation conditions allowed providing an early assessment of the neutron components of doses measured in EOLE reactor at CEA Cadarache with 10% uncertainty at 1σ.

WRC bulletin. A review of underclad cracking in pressure-vessel components

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

Vinckier, A.G.; Pense, A.W.

1974-01-01

This review of cracking underneath the weld cladding is to determine what factors contribute to this condition, and to outline means for alleviating or eliminating this condition. Considerable data on manufacture, heat treatment, and cladding of heavy-section pressure-vessel steels for nuclear service are also included. Three factors in combination that promote underclad cracking are susceptible microstructure, favorable residual-stress pattern, and a thermal treatment bringing the steel into a critical temperature region (600-650/sup 0/C) where creep ductility is low. High-heat-input weld-overlay cladding produces the susceptible microstructure and residual-stress pattern and postweld heat treatment produces the critical temperature. Most underclad cracking wasmore » found in SA508 Class 2 steel forgings clad with one-layer submerged-arc strip electrodes or multi-electrode processes. It was not produced in SA533 Grade B plate or when multilayer overlay processes were used. Underclad cracking can be reduced or eliminated by a two-layer cladding technique, by controlling welding process variables (low heat input), renormalizing the sensitive HAZ region prior to heat treatment, by use of nonsusceptible materials, or by eliminating the postweld heat treatment. Results of a questionnaire survey are also included. 50 references. (DLC)« less

Fault Diagnosis for the Heat Exchanger of the Aircraft Environmental Control System Based on the Strong Tracking Filter

PubMed Central

Ma, Jian; Lu, Chen; Liu, Hongmei

2015-01-01

The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system’s efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger. PMID:25823010

Fault diagnosis for the heat exchanger of the aircraft environmental control system based on the strong tracking filter.

PubMed

Ma, Jian; Lu, Chen; Liu, Hongmei

2015-01-01

The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.

The impact of standard and hard-coded parameters on the hydrologic fluxes in the Noah-MP land surface model

NASA Astrophysics Data System (ADS)

Cuntz, Matthias; Mai, Juliane; Samaniego, Luis; Clark, Martyn; Wulfmeyer, Volker; Branch, Oliver; Attinger, Sabine; Thober, Stephan

2016-09-01

Land surface models incorporate a large number of process descriptions, containing a multitude of parameters. These parameters are typically read from tabulated input files. Some of these parameters might be fixed numbers in the computer code though, which hinder model agility during calibration. Here we identified 139 hard-coded parameters in the model code of the Noah land surface model with multiple process options (Noah-MP). We performed a Sobol' global sensitivity analysis of Noah-MP for a specific set of process options, which includes 42 out of the 71 standard parameters and 75 out of the 139 hard-coded parameters. The sensitivities of the hydrologic output fluxes latent heat and total runoff as well as their component fluxes were evaluated at 12 catchments within the United States with very different hydrometeorological regimes. Noah-MP's hydrologic output fluxes are sensitive to two thirds of its applicable standard parameters (i.e., Sobol' indexes above 1%). The most sensitive parameter is, however, a hard-coded value in the formulation of soil surface resistance for direct evaporation, which proved to be oversensitive in other land surface models as well. Surface runoff is sensitive to almost all hard-coded parameters of the snow processes and the meteorological inputs. These parameter sensitivities diminish in total runoff. Assessing these parameters in model calibration would require detailed snow observations or the calculation of hydrologic signatures of the runoff data. Latent heat and total runoff exhibit very similar sensitivities because of their tight coupling via the water balance. A calibration of Noah-MP against either of these fluxes should therefore give comparable results. Moreover, these fluxes are sensitive to both plant and soil parameters. Calibrating, for example, only soil parameters hence limit the ability to derive realistic model parameters. It is thus recommended to include the most sensitive hard-coded model parameters that were exposed in this study when calibrating Noah-MP.

Land surface and atmospheric conditions associated with heat waves over the Chickasaw Nation in the South Central United States

NASA Astrophysics Data System (ADS)

Lee, Eungul; Bieda, Rahama; Shanmugasundaram, Jothiganesh; Basara Richter, Heather

2016-06-01

Exposure to extreme heat was reconstructed based on regional land-atmosphere processes from 1979 to 2010 in the South Central U.S. The study region surrounds the Chickasaw Nation (CN), a predominantly Native American population with a highly prevalent burden of climate-sensitive chronic diseases. Land surface and atmospheric conditions for summer heat waves were analyzed during spring (March-April-May, MAM) and summer (June-July-August, JJA) based on the Climate and Ocean: Variability, Predictability, and Change maximum temperature definition for heat wave frequency (HWF). The spatial-temporal pattern of HWF was determined using empirical orthogonal function (EOF) analysis and the corresponding principle component time series of the first EOF of HWF. Statistically significant analyses of observed conditions indicated that sensible heat increased and latent heat fluxes decreased with high HWF in the South Central U.S. The largest positive correlations of sensible heat flux to HWF and the largest negative correlations of latent heat flux to HWF were specifically observed over the CN. This is a significantly different energy transfer regime due to less available soil moisture during the antecedent MAM and JJA. The higher sensible heat from dry soil could cause significant warming from the near surface (>2.0°C) to the lower troposphere (>1.5°C), and accumulated boundary layer heat could induce the significant patterns of higher geopotential height and enhance anticyclonic circulations (negative vorticity anomaly) at the midtroposphere. Results suggested a positive land-atmosphere feedback associated with heat waves and called attention to the need for region-specific climate adaptation planning.

Land surface and atmospheric conditions associated with heat waves in the South Central United States

NASA Astrophysics Data System (ADS)

Lee, Eungul; Bieda, Rahama; Shanmugasundaram, Jothiganesh; Richter, Heather

2017-04-01

Exposure to extreme heat was reconstructed based on regional land-atmosphere processes from 1979 to 2010 in the South Central U.S. The study region surrounds the Chickasaw Nation (CN), a predominantly Native American population with a highly prevalent burden of climate-sensitive chronic diseases. Land surface and atmospheric conditions for summer heat waves were analyzed during spring (March-April-May, MAM) and summer (June-July-August, JJA) based on the Climate and Ocean: Variability, Predictability, and Change maximum temperature definition for heat wave frequency (HWF). The spatial-temporal pattern of HWF was determined using empirical orthogonal function (EOF) analysis and the corresponding principle component time series of the first EOF of HWF. Statistically significant analyses of observed conditions indicated that sensible heat increased and latent heat fluxes decreased with high HWF in the South Central U.S. The largest positive correlations of sensible heat flux to HWF and the largest negative correlations of latent heat flux to HWF were specifically observed over the CN. This is a significantly different energy transfer regime due to less available soil moisture during the antecedent MAM and JJA. The higher sensible heat from dry soil could cause significant warming from the near surface (> 2.0°C) to the lower troposphere (> 1.5°C), and accumulated boundary layer heat could induce the significant patterns of higher geopotential height and enhance anticyclonic circulations (negative vorticity anomaly) at the midtroposphere. Results suggested a positive land-atmosphere feedback associated with heat waves and called attention to the need for region-specific climate adaptation planning.

Capsaicin-sensitive sensory nerves exert complex regulatory functions in the serum-transfer mouse model of autoimmune arthritis.

PubMed

Borbély, Éva; Botz, Bálint; Bölcskei, Kata; Kenyér, Tibor; Kereskai, László; Kiss, Tamás; Szolcsányi, János; Pintér, Erika; Csepregi, Janka Zsófia; Mócsai, Attila; Helyes, Zsuzsanna

2015-03-01

The K/BxN serum-transfer arthritis is a widely-used translational mouse model of rheumatoid arthritis, in which the immunological components have thoroughly been investigated. In contrast, little is known about the role of sensory neural factors and the complexity of neuro-immune interactions. Therefore, we analyzed the involvement of capsaicin-sensitive peptidergic sensory nerves in autoantibody-induced arthritis with integrative methodology. Arthritogenic K/BxN or control serum was injected to non-pretreated mice or resiniferatoxin (RTX)-pretreated animals where capsaicin-sensitive nerves were inactivated. Edema, touch sensitivity, noxious heat threshold, joint function, body weight and clinical arthritis severity scores were determined repeatedly throughout two weeks. Micro-CT and in vivo optical imaging to determine matrix-metalloproteinase (MMP) and neutrophil-derived myeloperoxidase (MPO) activities, semiquantitative histopathological scoring and radioimmunoassay to measure somatostatin in the joint homogenates were also performed. In RTX-pretreated mice, the autoantibody-induced joint swelling, arthritis severity score, MMP and MPO activities, as well as histopathological alterations were significantly greater compared to non-pretreated animals. Self-control quantification of the bone mass revealed decreased values in intact female mice, but significantly greater arthritis-induced pathological bone formation after RTX-pretreatment. In contrast, mechanical hyperalgesia from day 10 was smaller after inactivating capsaicin-sensitive afferents. Although thermal hyperalgesia did not develop, noxious heat threshold was significantly higher following RTX pretreatment. Somatostatin-like immunoreactivity elevated in the tibiotarsal joints in non-pretreated, which was significantly less in RTX-pretreated mice. Although capsaicin-sensitive sensory nerves mediate mechanical hyperalgesia in the later phase of autoantibody-induced chronic arthritis, they play important anti-inflammatory roles at least partially through somatostatin release. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Capsaicin-sensitive sensory nerves exert complex regulatory functions in the serum-transfer mouse model of autoimmune arthritis

PubMed Central

Borbély, Éva; Botz, Bálint; Bölcskei, Kata; Kenyér, Tibor; Kereskai, László; Kiss, Tamás; Szolcsányi, János; Pintér, Erika; Csepregi, Janka Zsófia; Mócsai, Attila; Helyes, Zsuzsanna

2015-01-01

Objective The K/BxN serum-transfer arthritis is a widely-used translational mouse model of rheumatoid arthritis, in which the immunological components have thoroughly been investigated. In contrast, little is known about the role of sensory neural factors and the complexity of neuro–immune interactions. Therefore, we analyzed the involvement of capsaicin-sensitive peptidergic sensory nerves in autoantibody-induced arthritis with integrative methodology. Methods Arthritogenic K/BxN or control serum was injected to non-pretreated mice or resiniferatoxin (RTX)-pretreated animals where capsaicin-sensitive nerves were inactivated. Edema, touch sensitivity, noxious heat threshold, joint function, body weight and clinical arthritis severity scores were determined repeatedly throughout two weeks. Micro-CT and in vivo optical imaging to determine matrix-metalloproteinase (MMP) and neutrophil-derived myeloperoxidase (MPO) activities, semiquantitative histopathological scoring and radioimmunoassay to measure somatostatin in the joint homogenates were also performed. Results In RTX-pretreated mice, the autoantibody-induced joint swelling, arthritis severity score, MMP and MPO activities, as well as histopathological alterations were significantly greater compared to non-pretreated animals. Self-control quantification of the bone mass revealed decreased values in intact female mice, but significantly greater arthritis-induced pathological bone formation after RTX-pretreatment. In contrast, mechanical hyperalgesia from day 10 was smaller after inactivating capsaicin-sensitive afferents. Although thermal hyperalgesia did not develop, noxious heat threshold was significantly higher following RTX pretreatment. Somatostatin-like immunoreactivity elevated in the tibiotarsal joints in non-pretreated, which was significantly less in RTX-pretreated mice. Conclusions Although capsaicin-sensitive sensory nerves mediate mechanical hyperalgesia in the later phase of autoantibody-induced chronic arthritis, they play important anti-inflammatory roles at least partially through somatostatin release. PMID:25524130

Antibody response to a sterile filtered PPD tuberculin in M. bovis infected and M. bovis sensitized cattle.

PubMed

Rennie, Bryan; Filion, Lionel G; Smart, Nonie

2010-11-09

Bovine tuberculosis, caused by Mycobacterium bovis, afflicts approximately 50 million cattle worldwide and is detected by the tuberculin skin test (TST). While it has long been recognized that purified protein derivative (PPD) tuberculin is composed of a mixture of M. bovis derived protein components, little is known about the quality, relative quantity and identity of the proteins that make up PPD tuberculin. We manufactured a sterile filtered PPD tuberculin (SF-PPD) from a nine-week-old M. bovis culture supernatant in order to characterise the culture filtrate proteins (CFP) which make up M. bovis PPD tuberculin and to compare the antibody response of M. bovis infected versus M. bovis sensitized cattle. SF-PPD resolved into approximately 200 discrete spots using two-dimensional polyacrylamide gel electrophoresis (2-DE) while fewer than 65 spots could be discerned from 2-DE gels of tuberculin derived from autoclaved culture supernatant. Two dimensional Western blot analyses indicated that sera from M. bovis sensitized cattle recognized additional SF-PPD antigens as compared to M. bovis infected cattle at seven weeks post infection/sensitization. However, application of a comparative tuberculin skin test resulted in an antibody boosting response to the same set of M. bovis CFPs in both the M. bovis infected and M. bovis sensitized cattle. We concluded that it is the heat sterilization of the M. bovis CFPs that causes severe structural changes to the M. bovis proteins. This work suggests that M. bovis infected cattle and cattle artificially sensitized to M. bovis with an injection of heat killed cells exhibit similar antibody responses to M. bovis antigens.

Engineering Analysis of Thermal-Load Components in the Process of Heating of Pet Preforms

NASA Astrophysics Data System (ADS)

Sidorov, D. É.; Kolosov, A. E.; Kazak, I. A.; Pogorelyi, A. V.

2018-05-01

The influence of thermal-load components (convection, collimated and uncollimated components of infrared radiation) in the process of production of PET packaging on the heating of PET preforms has been assessed. It has been established that the collimated component of infrared radiation ensures most (up to 70%) of the thermal energy in the process of heating of a PET preform.

Sensitivities Affecting Heat and Urban Heat Island Effect on Local Scale Projected to Neighborhood Scale in Baltimore, Maryland

NASA Astrophysics Data System (ADS)

Sze, C.; Zaitchik, B. F.; Scott, A.

2015-12-01

Urban regions are often impacted more by heat than adjacent rural areas, which is a phenomenon known as the urban heat island (UHI) effect. Urban areas are also highly heterogeneous and notoriously difficult to monitor using standard meteorological protocols—the hottest microclimates within a city often occur in locations that lack open, representative installation sites that are an adequate distance from buildings and direct heat sources. To investigate the challenges of monitoring urban heat, this study examines the sensitivity of temperature and humidity sensors currently used in a Baltimore UHI monitoring network to differences in sun exposure, material on which the data collecting instrument is attached, and land cover class of the vicinity. Sensitivity to sun exposure and attachment site can be interpreted as sources of uncertainty for urban heat monitoring, while sensitivity to land cover may reflect a true source of local temperature and humidity variability. In this study, we present results from a test deployment designed to assess the sensitivity of heat measurements to each of these three factors. We then apply these results to interpret measurements taken across the entire Baltimore UHI monitoring network. These results can then be used to improve heat measurements and more accurately represent and quantify the UHI effect on a broader scale, such as in neighborhoods or urban centers.

Cell biological effects of hyperthermia alone or combined with radiation or drugs: a short introduction to newcomers in the field.

PubMed

Kampinga, Harm H

2006-05-01

Hyperthermia results in protein unfolding that, if not properly chaperoned by Heat Shock Proteins (HSP), can lead to irreversible and toxic protein aggregates. Elevating HSP prior to heating makes cells thermotolerant. Hyperthermia also can enhance the sensitivity of cells to radiation and drugs. This sensitization to drugs or radiation is not directly related to altered HSP expression. However, altering HSP expression before heat and radiation or drug treatment will affect the extent of thermal sensitization because the HSP will attenuate the heat-induced protein damage that is responsible for radiation- or drug-sensitization. For thermal radiosensitization, nuclear protein damage is considered to be responsible for hyperthermic effects on DNA repair, in particular base excision repair. Hyperthermic drug sensitization can be seen for a number of anti-cancer drugs, especially of alkylating agents. Synergy between heat and drugs may arise from multiple events such as heat damage to ABC transporters (drug accumulation), intra-cellular drug detoxification pathways and repair of drug-induced DNA adducts. This may be why cells with acquired drug resistance (often multi-factorial) can be made responsive to drugs again by combining the drug treatment with heat.

The development of a cryogenic integrated system with the working temperature of 100K

NASA Astrophysics Data System (ADS)

Liu, En'guang; Wu, Yi'nong; Wang, Yueming; Wen, Jiajia; Lv, Gang; Li, Chunlai; Hou, Jia; Yuan, Liyin

2016-05-01

In the infrared system, cooling down the optic components' temperature is a better choice to decrease the background radiation and maximize the sensitivity. This paper presented a 100K cryogenic optical system, for which an integrated designation of mechanical cooler, flexible thermal link and optical bench was developed. The whole infrared optic components which were assembled in a vacuum box were cooled down to 100K by two mechanical coolers. Low thermal conductivity supports and low emissivity multi-layers were used to reduce the cryogenic optical system's heat loss. The experiment results showed that in about eight hours, the temperature of the optical components reached 100K from room temperature, and the vibration from the mechanical coolers nearly have no affection to the imaging process by using of thermal links. Some experimental results of this cryogenic system will be discussed in this paper.

Active pain coping is associated with the response in real-time fMRI neurofeedback during pain.

PubMed

Emmert, Kirsten; Breimhorst, Markus; Bauermann, Thomas; Birklein, Frank; Rebhorn, Cora; Van De Ville, Dimitri; Haller, Sven

2017-06-01

Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback is used as a tool to gain voluntary control of activity in various brain regions. Little emphasis has been put on the influence of cognitive and personality traits on neurofeedback efficacy and baseline activity. Here, we assessed the effect of individual pain coping on rt-fMRI neurofeedback during heat-induced pain. Twenty-eight healthy subjects completed the Coping Strategies Questionnaire (CSQ) prior to scanning. The first part of the fMRI experiment identified target regions using painful heat stimulation. Then, subjects were asked to down-regulate the pain target brain region during four neurofeedback runs with painful heat stimulation. Functional MRI analysis included correlation analysis between fMRI activation and pain ratings as well as CSQ ratings. At the behavioral level, the active pain coping (first principal component of CSQ) was correlated with pain ratings during neurofeedback. Concerning neuroimaging, pain sensitive regions were negatively correlated with pain coping. During neurofeedback, the pain coping was positively correlated with activation in the anterior cingulate cortex, prefrontal cortex, hippocampus and visual cortex. Thermode temperature was negatively correlated with anterior insula and dorsolateral prefrontal cortex activation. In conclusion, self-reported pain coping mechanisms and pain sensitivity are a source of variance during rt-fMRI neurofeedback possibly explaining variations in regulation success. In particular, active coping seems to be associated with successful pain regulation.

A Practical Application of Microcomputers to Control an Active Solar System.

ERIC Educational Resources Information Center

Goldman, David S.; Warren, William

1984-01-01

Describes the design and implementation of a microcomputer-based model active solar heating system. Includes discussions of: (1) the active solar components (solar collector, heat exchanger, pump, and fan necessary to provide forced air heating); (2) software components; and (3) hardware components (in the form of sensors and actuators). (JN)

46 CFR 56.80-15 - Heat treatment of bends and formed components.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Heat treatment of bends and formed components. 56.80-15... PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-15 Heat treatment of bends and formed... forming requires no subsequent heat treatment. (b) Ferritic alloy steel piping which has been heated for...

46 CFR 56.80-15 - Heat treatment of bends and formed components.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Heat treatment of bends and formed components. 56.80-15... PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-15 Heat treatment of bends and formed... forming requires no subsequent heat treatment. (b) Ferritic alloy steel piping which has been heated for...

46 CFR 56.80-15 - Heat treatment of bends and formed components.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Heat treatment of bends and formed components. 56.80-15... PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-15 Heat treatment of bends and formed... forming requires no subsequent heat treatment. (b) Ferritic alloy steel piping which has been heated for...

46 CFR 56.80-15 - Heat treatment of bends and formed components.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Heat treatment of bends and formed components. 56.80-15... PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-15 Heat treatment of bends and formed... forming requires no subsequent heat treatment. (b) Ferritic alloy steel piping which has been heated for...

46 CFR 56.80-15 - Heat treatment of bends and formed components.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Heat treatment of bends and formed components. 56.80-15... PIPING SYSTEMS AND APPURTENANCES Bending and Forming § 56.80-15 Heat treatment of bends and formed... forming requires no subsequent heat treatment. (b) Ferritic alloy steel piping which has been heated for...

Electron beam weld development on a Filter Pack Assembly

NASA Astrophysics Data System (ADS)

Dereskiewicz, J. P.

1994-06-01

A continuous electron beam welding procedure was developed to replace the manual gas tungsten arc welding procedure on the Filter Pack Assembly. A statistical study was used to evaluate the feasibility of electron beam welding 6061-T6 aluminum covers to A356 cast weldments throughout the joint tolerance range specified on product drawings. Peak temperature exposures were not high enough to degrade the heat sensitive electrical components inside the cast weldment. Actual weldments with alodine coating on the weld joint area were successfully cleaned using a nonmetallic fiberglass brush cleaning method.

Protection of temperature sensitive biomedical products using molecular alloys as phase change material.

PubMed

Mondieig, Denise; Rajabalee, Fazil; Laprie, Alain; Oonk, Harry A J; Calvet, Thereza; Cuevas-Diarte, Miguel Angel

2003-04-01

In this paper we present an example of the application of molecular alloys for thermal protection of biomedical products during transport or storage. Particularly, thermal protection of blood elements have been considered at different temperatures. All steps from basic research to marketing have been addressed. The high latent heat of fusion of the components allows us to propose molecular alloys as materials for thermal energy storage and also for thermal protection over a large range of temperatures, which can be used in many industrial sectors.

9975 Shipping package component long-term degradation rates

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

Daugherty, W. L.

Special nuclear materials are being stored in the K-Area Complex using 3013 containers that are held within Model 9975 shipping packages. The service life for these packages in storage was recently increased from 15 to 20 years, since some of these packages have been stored for nearly 15 years. A strategy is also being developed whereby such storage might be extended beyond 20 years. This strategy is based on recent calculations that support acceptable 9975 package performance for 20 years with internal heat loads up to 19 watts, and identifies a lower heat load limit for which the package componentsmore » should degrade at half the bounding rate or less, thus doubling the effective storage life for these lower wattage packages. The components of the 9975 package that are sensitive to aging under storage conditions are the fiberboard overpack and the O-ring seals, although some degradation of the lead shield and outer drum are also possible. This report summarizes degradation rates applicable to lower heat load storage conditions. In particular, the O-ring seals should provide leak-tight performance for more than 40 years in packages for which their maximum temperature is ≤135 °F. Similarly, the fiberboard should remain acceptable in performance of its required safety functions for up to 40 years in packages with a maximum fiberboard temperature ≤125 °F.« less

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.

Temporal trends in human vulnerability to excessive heat

NASA Astrophysics Data System (ADS)

Sheridan, Scott C.; Allen, Michael J.

2018-04-01

Over recent decades, studies have examined various morbidity and mortality outcomes associated with heat exposure. This review explores the collective knowledge of the temporal trends of heat on human health, with regard to the hypothesis that humans are less vulnerable to heat events presently than in the past. Using Web of Science and Scopus, the authors identified all peer-reviewed articles that contained keywords on human impact (e.g. mortality, morbidity) and meteorological component (e.g. heat, heatwave). After sorting, a total of 71 articles, both case studies and epidemiological studies, contained explicit assessments of temporal trends in human vulnerability, and thus were used in this review. Most of the studies utilized mortality data, focused on the developed world, and showed a general decrease in heat sensitivity. Factors such as the implementation of a heat warning system, increased awareness, and improved quality of life were cited as contributing factors that led to the decreased impact of heat. Despite the overall recent decreases in heat vulnerability, spatial variability was shown, and differences with respect to health outcomes were also discussed. Several papers noted increases in heat’s impact on human health, particularly when unprecedented conditions occurred. Further, many populations, from outdoor workers to rural residents, in addition to the populations in much of the developing world, have been significantly underrepresented in research to date, and temporal changes in their vulnerability should be assessed in future studies. Moreover, continued monitoring and improvement of heat intervention is needed; with projected changes in the frequency, duration, and intensity of heat events combined with shifts in demographics, heat will remain a major public health issue moving forward.

Optimization of Borehole Thermal Energy Storage System Design Using Comprehensive Coupled Simulation Models

NASA Astrophysics Data System (ADS)

Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Formhals, Julian; Bär, Kristian; Sass, Ingo

2017-04-01

Large-scale borehole thermal energy storage (BTES) is a promising technology in the development of sustainable, renewable and low-emission district heating concepts. Such systems consist of several components and assemblies like the borehole heat exchangers (BHE), other heat sources (e.g. solarthermics, combined heat and power plants, peak load boilers, heat pumps), distribution networks and heating installations. The complexity of these systems necessitates numerical simulations in the design and planning phase. Generally, the subsurface components are simulated separately from the above ground components of the district heating system. However, as fluid and heat are exchanged, the subsystems interact with each other and thereby mutually affect their performances. For a proper design of the overall system, it is therefore imperative to take into account the interdependencies of the subsystems. Based on a TCP/IP communication we have developed an interface for the coupling of a simulation package for heating installations with a finite element software for the modeling of the heat flow in the subsurface and the underground installations. This allows for a co-simulation of all system components, whereby the interaction of the different subsystems is considered. Furthermore, the concept allows for a mathematical optimization of the components and the operational parameters. Consequently, a finer adjustment of the system can be ensured and a more precise prognosis of the system's performance can be realized.

Presence of CP4-EPSPS Component in Roundup Ready Soybean-Derived Food Products

PubMed Central

Wu, Honghong; Zhang, Yu; Zhu, Changqing; Xiao, Xiao; Zhou, Xinghu; Xu, Sheng; Shen, Wenbiao; Huang, Ming

2012-01-01

With the widespread use of Roundup Ready soya (event 40-3-2) (RRS), the traceability of transgenic components, especially protein residues, in different soya-related foodstuffs has become an important issue. In this report, transgenic components in commercial soya (including RRS) protein concentrates were firstly detected by using polymerase chain reaction (PCR) and western blot. The results illustrated the different degradation patterns of the cp4-epsps gene and corresponding protein in RRS-derived protein concentrates. Furthermore, western blot was applied to investigate the single factor of food processing and the matrix on the disintegration of CP4-EPSPS protein in RRS powder and soya-derived foodstuffs, and trace the degradation patterns during the food production chain. Our results suggested that the exogenous full length of CP4-EPSPS protein in RRS powder was distinctively sensitive to various heat treatments, including heat, microwave and autoclave (especially), and only one degradation fragment (23.4 kD) of CP4-EPSPS protein was apparently observed when autoclaving was applied. By tracing the protein degradation during RRS-related products, including tofu, tou-kan, and bean curd sheets, however, four degradation fragments (42.9, 38.2, 32.2 and 23.4 kD) were displayed, suggesting that both boiling and bittern adding procedures might have extensive effects on CP4-EPSPS protein degradation. Our results thus confirmed that the distinctive residues of the CP4-EPSPS component could be traced in RRS-related foodstuffs. PMID:22408431

Electronic waste disassembly with industrial waste heat.

PubMed

Chen, Mengjun; Wang, Jianbo; Chen, Haiyian; Ogunseitan, Oladele A; Zhang, Mingxin; Zang, Hongbin; Hu, Jiukun

2013-01-01

Waste printed circuit boards (WPCBs) are resource-rich but hazardous, demanding innovative strategies for post-consumer collection, recycling, and mining for economically precious constituents. A novel technology for disassembling electronic components from WPCBs is proposed, using hot air to melt solders and to separate the components and base boards. An automatic heated-air disassembling equipment was designed to operate at a heating source temperature at a maximum of 260 °C and an inlet pressure of 0.5 MPa. A total of 13 individual WPCBs were subjected to disassembling tests at different preheat temperatures in increments of 20 °C between 80 and 160 °C, heating source temperatures ranging from 220 to 300 °C in increments of 20 °C, and incubation periods of 1, 2, 4, 6, or 8 min. For each experimental treatment, the disassembly efficiency was calculated as the ratio of electronic components released from the board to the total number of its original components. The optimal preheat temperature, heating source temperature, and incubation period to disassemble intact components were 120 °C, 260 °C, and 2 min, respectively. The disassembly rate of small surface mount components (side length ≤ 3 mm) was 40-50% lower than that of other surface mount components and pin through hole components. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to electronic-waste recycling is proposed, providing an efficient, promising, and green method for both electronic component recovery and industrial exhaust heat reutilization.

Might outdoor heat stress be considered a proxy for the unperceivable effect of the ultraviolet-induced risk of erythema in Florence?

PubMed

Morabito, Marco; Grifoni, Daniele; Crisci, Alfonso; Fibbi, Luca; Orlandini, Simone; Gensini, Gian Franco; Zipoli, Gaetano

2014-01-05

Erythema is the most familiar short-term symptom of human skin associated with overexposure to unperceivable ultraviolet radiation (UV). However, people are able to perceive the warm infrared component of the solar radiation by means of thermal (dis)comfort. This study investigated the potentiality of perceived outdoor heat stress as a valuable proxy for the unperceivable effect of UV-induced risk of erythema in a Mediterranean city. Meteorological data and UVB (280-320nm) measurements were obtained for the 2004-2012 period by a weather station located in the municipality of Florence. Continuous measurements of erythemally effective UV (UVEry) were performed by means of a broadband temperature-corrected radiometer with the spectral response close to the erythemal action spectrum. Hourly UVEry doses were expressed as Standard Erythemal Doses (SEDs). The newly developed Universal Thermal Climate Index (UTCI), that represents the state-of-the-art of outdoor thermal (dis)comfort evaluation, was also assessed. Descriptive analyses of the hourly distribution per month of the frequencies of days with heat stress and UVEry exceeding 2.0, 3.0, 4.5 and 6.0 SEDs were carried out based on the general skin-type characteristics. The association between UVEry and UTCI was analyzed by a two-way contingency table approach. The probability of UVEry exceeding specific SED thresholds when heat stress occurs was often significantly higher than the same probability when no heat stress is perceived. Furthermore, increased magnitudes of the ratios, ranging from the very sensitive to the minimally sensitive skin types, were also found. However, during several months, too many days occur without any signs of heat discomfort, even when people may be exposed to relevant doses of harmful UVEry for the skin of various phototypes. These findings underlie the need for public health authorities to provide differentiated advice per month in relation to potential UV skin damage in the city of Florence. Copyright © 2013 Elsevier B.V. All rights reserved.

Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

DOEpatents

Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

2015-11-10

Methods are provided for facilitating cooling of an electronic component. The methods include providing: a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

DOEpatents

Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

2015-05-12

Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

The effect of component junction tapering on miniature cryocooler performance

NASA Astrophysics Data System (ADS)

Conrad, Ted; Pathak, Mihir G.; Ghiaasiaan, S. Mostafa; Kirkconnell, Carl

2012-06-01

Due to their relatively smaller volume and available cooling power, miniature cryocoolers are likely to be more sensitive to hydrodynamic losses than their full scale counterparts. Abrupt changes in diameter between cryocooler components are a possible source of such losses as flow separation and recirculation may occur at these points. Underutilization of regions of the regenerator and heat exchanger porous matrices may also occur due to jetting of fluid into these components. Eliminating such abrupt diameter changes by tapering transitions between cryocooler components may therefore improve system performance. The effects of various tapers applied at component interfaces on the performance of miniature pulse tube cryocoolers were investigated using system-level CFD models. A miniature scale pulse tube cryocooler design whose suitability for cryocooling under ideal conditions has been theoretically demonstrated was used as the basis for these models. Transitions between different combinations of open and porous regions were considered; tapers or chamfers were applied to these component junctions and the performance predictions for the resulting systems were compared to those for a model with sharp component transitions. Visualizations of the predicted flow patterns were also used to determine the effects of the applied tapers on the flow within the pulse tube.

Selective disruption of high sensitivity heat activation but not capsaicin activation of TRPV1 channels by pore turret mutations

PubMed Central

Cui, Yuanyuan; Yang, Fan; Cao, Xu; Yarov-Yarovoy, Vladimir

2012-01-01

The capsaicin receptor transient receptor potential vanilloid (TRPV)1 is a highly heat-sensitive ion channel. Although chemical activation and heat activation of TRPV1 elicit similar pungent, painful sensation, the molecular mechanism underlying synergistic activation remains mysterious. In particular, where the temperature sensor is located and whether heat and capsaicin share a common activation pathway are debated. To address these fundamental issues, we searched for channel mutations that selectively affected one form of activation. We found that deletion of the first 10 amino acids of the pore turret significantly reduced the heat response amplitude and shifted the heat activation threshold, whereas capsaicin activation remained unchanged. Removing larger portions of the turret disrupted channel function. Introducing an artificial sequence to replace the deleted region restored sensitive capsaicin activation in these nonfunctional channels. The heat activation, however, remained significantly impaired, with the current exhibiting diminishing heat sensitivity to a level indistinguishable from that of a voltage-gated potassium channel, Kv7.4. Our results demonstrate that heat and capsaicin activation of TRPV1 are structurally and mechanistically distinct processes, and the pore turret is an indispensible channel structure involved in the heat activation process but is not part of the capsaicin activation pathway. Synergistic effect of heat and capsaicin on TRPV1 activation may originate from convergence of the two pathways on a common activation gate. PMID:22412190

Heat treating of manufactured components

DOEpatents

Ripley, Edward B [Knoxville, TN

2012-05-22

An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material is disclosed. The system typically includes an insulating vessel placed within a microwave applicator chamber. A moderating material is positioned inside the insulating vessel so that a substantial portion of the exterior surface of each component for heat treating is in contact with the moderating material.

Emergency heat removal system for a nuclear reactor

DOEpatents

Dunckel, Thomas L.

1976-01-01

A heat removal system for nuclear reactors serving as a supplement to an Emergency Core Cooling System (ECCS) during a Loss of Coolant Accident (LOCA) comprises a plurality of heat pipes having one end in heat transfer relationship with either the reactor pressure vessel, the core support grid structure or other in-core components and the opposite end located in heat transfer relationship with a heat exchanger having heat transfer fluid therein. The heat exchanger is located external to the pressure vessel whereby excessive core heat is transferred from the above reactor components and dissipated within the heat exchanger fluid.

Weichselian permafrost depth in the Netherlands: a comprehensive uncertainty and sensitivity analysis

NASA Astrophysics Data System (ADS)

Govaerts, Joan; Beerten, Koen; ten Veen, Johan

2016-11-01

The Rupelian clay in the Netherlands is currently the subject of a feasibility study with respect to the storage of radioactive waste in the Netherlands (OPERA-project). Many features need to be considered in the assessment of the long-term evolution of the natural environment surrounding a geological waste disposal facility. One of these is permafrost development as it may have an impact on various components of the disposal system, including the natural environment (hydrogeology), the natural barrier (clay) and the engineered barrier. Determining how deep permafrost might develop in the future is desirable in order to properly address the possible impact on the various components. It is expected that periglacial conditions will reappear at some point during the next several hundred thousands of years, a typical time frame considered in geological waste disposal feasibility studies. In this study, the Weichselian glaciation is used as an analogue for future permafrost development. Permafrost depth modelling using a best estimate temperature curve of the Weichselian indicates that permafrost would reach depths between 155 and 195 m. Without imposing a climatic gradient over the country, deepest permafrost is expected in the south due to the lower geothermal heat flux and higher average sand content of the post-Rupelian overburden. Accounting for various sources of uncertainty, such as type and impact of vegetation, snow cover, surface temperature gradients across the country, possible errors in palaeoclimate reconstructions, porosity, lithology and geothermal heat flux, stochastic calculations point out that permafrost depth during the coldest stages of a glacial cycle such as the Weichselian, for any location in the Netherlands, would be 130-210 m at the 2σ level. In any case, permafrost would not reach depths greater than 270 m. The most sensitive parameters in permafrost development are the mean annual air temperatures and porosity, while the geothermal heat flux is the crucial parameter in permafrost degradation once temperatures start rising again.

Sensitive thermal microsensor with pn junction for heat measurement of a single cell

NASA Astrophysics Data System (ADS)

Yamada, Taito; Inomata, Naoki; Ono, Takahito

2016-02-01

A sensitive thermal microsensor based on a pn junction diode for heat measurements of biological single cells is developed and evaluated. Using a fabricated device, we demonstrated the heat measurement of a single brown fat cell. The principle of the sensor relies on the temperature dependence of the pn junction diode resistance. This method has a capability of the highly thermal sensitivity by downsizing and the advantage of a simple experimental setup using electrical circuits without any special equipment. To achieve highly sensitive heat measurement of single cells, downsizing of the sensor is necessary to reduce the heat capacity of the sensor itself. The sensor with the pn junction diode can be downsized by microfabrication. A bridge beam structure with the pn junction diode as a thermal sensor is placed in vacuum using a microfludic chip to decrease the heat loss to the surroundings. A temperature coefficient of resistance of 1.4%/K was achieved. The temperature and thermal resolutions of the fabricated device are 1.1 mK and 73.6 nW, respectively. The heat measurements of norepinephrine stimulated and nonstimulated single brown fat cells were demonstrated, and different behaviors in heat generation were observed.

Dynamically limiting energy consumed by cooling apparatus

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Schmidt, Roger R.; Schultz, Mark D.

2015-05-26

Cooling apparatuses and methods are provided which include one or more coolant-cooled structures associated with an electronics rack, a coolant loop coupled in fluid communication with one or more passages of the coolant-cooled structure(s), one or more heat exchange units coupled to facilitate heat transfer from coolant within the coolant loop, and N controllable components associated with the coolant loop or the heat exchange unit(s), wherein N.gtoreq.1. The N controllable components facilitate circulation of coolant through the coolant loop or transfer of heat from the coolant via the heat exchange unit(s). A controller is coupled to the N controllable components, and dynamically adjusts operation of the N controllable components, based on Z input parameters and one or more specified constraints, to provide a specified cooling to the coolant-cooled structure(s), while limiting energy consumed by the N controllable components, wherein Z.gtoreq.1.

Active Thermal Control System Development for Exploration

NASA Technical Reports Server (NTRS)

Westheimer, David

2007-01-01

All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has been actively developing technologies that will enable future missions or will provide significant improvements over the state of the art technologies. These technologies have are targeted for application on the Crew Exploration Vehicle (CEV), or Orion, and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

Thermal Control System Development to Support the Crew Exploration Vehicle and Lunar Surface Access Module

NASA Technical Reports Server (NTRS)

Anderson, Molly; Westheimer, David

2006-01-01

All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has recently evaluated all of the agency s technology development work and identified key areas that must be addressed to aid in the successful development of a Crew Exploration Vehicle (CEV) and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

Irradiation-induced sensitization and stress corrosion cracking of Type 304 stainless steel core-internal components

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

Chung, H.M.; Ruther, W.E.; Sanecki, J.E.

1991-08-01

High- and commercial-purity heats of Type 304 stainless steel, obtained from neutron absorber tubes after irradiation to fluence levels of up to 2 {times} 10{sup 21} n{center dot}cm{sup {minus}2} (E > 1 MeV) in two boiling water reactors, were examined by Auger electron spectroscopy to characterize irradiation-induced grain- boundary segregation and depletion of alloying and impurity elements. Segregation of Si, P, Ni, and an unidentified element or compound that gives rise to an Auger energy peak at 59 eV was observed in the commercial-purity heat. Such segregation was negligible in high-purity material, except for Ni. No evidence of S segregationmore » was observed in either material. Cr depletion was more pronounced in the high-purity material than in the commercial-purity material. These observations suggest a synergism between the significant level of impurities and Cr depletion in the commercial-purity heat. In the absence of such synergism, Cr depletion appears more pronounced in the high-purity heat. Initial results of constant-extension-rate tests conducted on the two heats in air an in simulated BWR water were correlated with the results from analysis by Auger electron spectroscopy. 15 refs., 10 figs.« less

Parametric Analysis of Cyclic Phase Change and Energy Storage in Solar Heat Receivers

NASA Technical Reports Server (NTRS)

Hall, Carsie A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

1997-01-01

A parametric study on cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, has been performed. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results in the two-phase regime. Results indicate that parametric changes in receiver gas inlet temperature and receiver heat input effects higher sensitivity to changes in receiver gas exit temperatures.

Targeting HSP70-induced thermotolerance for design of thermal sensitizers.

PubMed

Calderwood, S K; Asea, A

2002-01-01

Thermal therapy has been shown to be an extremely powerful anti-cancer agent and a potent radiation sensitizer. However, the full potential of thermal therapy is hindered by a number of considerations including highly conserved heat resistance pathways in tumour cells and inhomogeneous heating of deep-seated tumours due to energy deposition and perfusion issues. This report reviews recent progress in the development of hyperthermia sensitizing drugs designed to specifically amplify the effects of hyperthermia. Such agents might be particularly useful in situations where heating is not adequate for the full biological effect or is not homogeneously delivered to tumours. The particular pathway concentrated on is thermotolerance, a complex, inducible cellular response that leads to heat resistance. This paper will concentrate on the molecular pathways of thermotolerance induction for designing inhibitors of heat resistance/thermal sensitizers, which may allow the full potential of thermal therapy to be utilized.

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.

Changes in the regulation of heat shock gene expression in neuronal cell differentiation.

PubMed

Oza, Jay; Yang, Jingxian; Chen, Kuang Yu; Liu, Alice Y-C

2008-01-01

Neuronal differentiation of the NG108-15 neuroblastoma-glioma hybrid cells is accompanied by a marked attenuation in the heat shock induction of the Hsp70-firefly luciferase reporter gene activity. Analysis of the amount and activation of heat shock factor 1, induction of mRNA(hsp), and the synthesis and accumulation of heat shock proteins (HSPs) in the undifferentiated and differentiated cells suggest a transcriptional mechanism for this attenuation. Concomitant with a decreased induction of the 72-kDa Hsp70 protein in the differentiated cells, there is an increased abundance of the constitutive 73-kDa Hsc70, a protein known to function in vesicle trafficking. Assessment of sensitivity of the undifferentiated and differentiated cells against stress-induced cell death reveals a significantly greater vulnerability of the differentiated cells toward the cytotoxic effects of arsenite and glutamate/glycine. This study shows that changes in regulation of the HSP and HSC proteins are components of the neuronal cell differentiation program and that the attenuated induction of HSPs likely contributes to neuronal vulnerability whereas the increased expression of Hsc70 likely has a role in neural-specific functions.

FT-IR-cPAS—New Photoacoustic Measurement Technique for Analysis of Hot Gases: A Case Study on VOCs

PubMed Central

Hirschmann, Christian Bernd; Koivikko, Niina Susanna; Raittila, Jussi; Tenhunen, Jussi; Ojala, Satu; Rahkamaa-Tolonen, Katariina; Marbach, Ralf; Hirschmann, Sarah; Keiski, Riitta Liisa

2011-01-01

This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements. PMID:22163900

Post-Test Analysis of 11% Break at PSB-VVER Experimental Facility using Cathare 2 Code

NASA Astrophysics Data System (ADS)

Sabotinov, Luben; Chevrier, Patrick

The best estimate French thermal-hydraulic computer code CATHARE 2 Version 2.5_1 was used for post-test analysis of the experiment “11% upper plenum break”, conducted at the large-scale test facility PSB-VVER in Russia. The PSB rig is 1:300 scaled model of VVER-1000 NPP. A computer model has been developed for CATHARE 2 V2.5_1, taking into account all important components of the PSB facility: reactor model (lower plenum, core, bypass, upper plenum, downcomer), 4 separated loops, pressurizer, horizontal multitube steam generators, break section. The secondary side is represented by recirculation model. A large number of sensitivity calculations has been performed regarding break modeling, reactor pressure vessel modeling, counter current flow modeling, hydraulic losses, heat losses. The comparison between calculated and experimental results shows good prediction of the basic thermal-hydraulic phenomena and parameters such as pressures, temperatures, void fractions, loop seal clearance, etc. The experimental and calculation results are very sensitive regarding the fuel cladding temperature, which show a periodical nature. With the applied CATHARE 1D modeling, the global thermal-hydraulic parameters and the core heat up have been reasonably predicted.

Temperature sensing of adipose tissue heating with the luminescent upconversion nanoparticles as nanothermometer: in vitro study

NASA Astrophysics Data System (ADS)

Yanina, I. Yu.; Volkova, E. K.; Zaharevich, A. M.; Konyukhova, J. G.; Kochubey, V. I.; Tuchin, V. V.

2017-03-01

The luminescence spectra of upconversion nanoparticles (UCNPs) imbedded in fat tissue were measured in a wide temperature range, from room to human body and further to hyperthermic temperatures. The two types of synthesized UCNP [NaYF4:Yb3+, Er3+] specimens, namely, powdered as-is and embedded into polymer film, were used. The results show that the luminescence of UCNPs placed under the adipose tissue layer is reasonably good sensitive to temperature change and reflects phase transitions of lipids in tissue cells. The most likely, multiple phase transitions are associated with the different components of fat cells such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The phase transitions of lipids were observed as the changes of the slope of the temperature dependence of UCNP luminescence intensity. The obtained results confirm a high sensitivity of the luminescent UCNPs to the temperature variations within tissues and show a strong potential for providing a controllable tissue thermolysis.

Recent Advances in Active Infrared Thermography for Non-Destructive Testing of Aerospace Components.

PubMed

Ciampa, Francesco; Mahmoodi, Pooya; Pinto, Fulvio; Meo, Michele

2018-02-16

Active infrared thermography is a fast and accurate non-destructive evaluation technique that is of particular relevance to the aerospace industry for the inspection of aircraft and helicopters' primary and secondary structures, aero-engine parts, spacecraft components and its subsystems. This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources. Besides traditional optically stimulated thermography, which uses external optical radiation such as flashes, heaters and laser systems, novel hybrid thermographic techniques are also investigated. These include ultrasonic stimulated thermography, which uses ultrasonic waves and the local damage resonance effect to enhance the reliability and sensitivity to micro-cracks, eddy current stimulated thermography, which uses cost-effective eddy current excitation to generate induction heating, and microwave thermography, which uses electromagnetic radiation at the microwave frequency bands to provide rapid detection of cracks and delamination. All these techniques are here analysed and numerous examples are provided for different damage scenarios and aerospace components in order to identify the strength and limitations of each thermographic technique. Moreover, alternative strategies to current external thermal excitation sources, here named as material-based thermography methods, are examined in this paper. These novel thermographic techniques rely on thermoresistive internal heating and offer a fast, low power, accurate and reliable assessment of damage in aerospace composites.

Recent Advances in Active Infrared Thermography for Non-Destructive Testing of Aerospace Components

PubMed Central

Mahmoodi, Pooya; Pinto, Fulvio; Meo, Michele

2018-01-01

Active infrared thermography is a fast and accurate non-destructive evaluation technique that is of particular relevance to the aerospace industry for the inspection of aircraft and helicopters’ primary and secondary structures, aero-engine parts, spacecraft components and its subsystems. This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources. Besides traditional optically stimulated thermography, which uses external optical radiation such as flashes, heaters and laser systems, novel hybrid thermographic techniques are also investigated. These include ultrasonic stimulated thermography, which uses ultrasonic waves and the local damage resonance effect to enhance the reliability and sensitivity to micro-cracks, eddy current stimulated thermography, which uses cost-effective eddy current excitation to generate induction heating, and microwave thermography, which uses electromagnetic radiation at the microwave frequency bands to provide rapid detection of cracks and delamination. All these techniques are here analysed and numerous examples are provided for different damage scenarios and aerospace components in order to identify the strength and limitations of each thermographic technique. Moreover, alternative strategies to current external thermal excitation sources, here named as material-based thermography methods, are examined in this paper. These novel thermographic techniques rely on thermoresistive internal heating and offer a fast, low power, accurate and reliable assessment of damage in aerospace composites. PMID:29462953

The thermo-sensitive gene expression signatures of spermatogenesis.

PubMed

Yadav, Santosh K; Pandey, Aastha; Kumar, Lokesh; Devi, Archana; Kushwaha, Bhavana; Vishvkarma, Rahul; Maikhuri, Jagdamba P; Rajender, Singh; Gupta, Gopal

2018-06-02

Spermatogenesis in most mammals (including human and rat) occurs at ~ 3 °C lower than body temperature in a scrotum and fails rapidly at 37 °C inside the abdomen. The present study investigates the heat-sensitive transcriptome and miRNAs in the most vulnerable germ cells (spermatocytes and round spermatids) that are primarily targeted at elevated temperature in a bid to identify novel targets for contraception and/or infertility treatment. Testes of adult male rats subjected to surgical cryptorchidism were obtained at 0, 24, 72 and 120 h post-surgery, followed by isolation of primary spermatocytes and round spermatids and purification to > 90% purity using a combination of trypsin digestion, centrifugal elutriation and density gradient centrifugation techniques. RNA isolated from these cells was sequenced by massive parallel sequencing technique to identify the most-heat sensitive mRNAs and miRNAs. Heat stress altered the expression of a large number of genes by ≥2.0 fold, out of which 594 genes (286↑; 308↓) showed alterations in spermatocytes and 154 genes (105↑; 49↓) showed alterations in spermatids throughout the duration of experiment. 62 heat-sensitive genes were common to both cell types. Similarly, 66 and 60 heat-sensitive miRNAs in spermatocytes and spermatids, respectively, were affected by ≥1.5 fold, out of which 6 were common to both the cell types. The study has identified Acly, selV, SLC16A7(MCT-2), Txnrd1 and Prkar2B as potential heat sensitive targets in germ cells, which may be tightly regulated by heat sensitive miRNAs rno-miR-22-3P, rno-miR-22-5P, rno-miR-129-5P, rno-miR-3560, rno-miR-3560 and rno-miR-466c-5P.

Reliability analysis of component-level redundant topologies for solid-state fault current limiter

NASA Astrophysics Data System (ADS)

Farhadi, Masoud; Abapour, Mehdi; Mohammadi-Ivatloo, Behnam

2018-04-01

Experience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component level. This article presents a comparative reliability analysis between different component-level redundant designs for solid-state fault current limiter. The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of (i) ambient temperature, (ii) power loss of the semiconductor switch and (iii) thermal resistance of heat sink. Also, results' sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelised costs of different configurations are analysed for a fair comparison.

The effects of heat stress in Italian Holstein dairy cattle.

PubMed

Bernabucci, U; Biffani, S; Buggiotti, L; Vitali, A; Lacetera, N; Nardone, A

2014-01-01

The data set for this study comprised 1,488,474 test-day records for milk, fat, and protein yields and fat and protein percentages from 191,012 first-, second-, and third-parity Holstein cows from 484 farms. Data were collected from 2001 through 2007 and merged with meteorological data from 35 weather stations. A linear model (M1) was used to estimate the effects of the temperature-humidity index (THI) on production traits. Least squares means from M1 were used to detect the THI thresholds for milk production in all parities by using a 2-phase linear regression procedure (M2). A multiple-trait repeatability test-model (M3) was used to estimate variance components for all traits and a dummy regression variable (t) was defined to estimate the production decline caused by heat stress. Additionally, the estimated variance components and M3 were used to estimate traditional and heat-tolerance breeding values (estimated breeding values, EBV) for milk yield and protein percentages at parity 1. An analysis of data (M2) indicated that the daily THI at which milk production started to decline for the 3 parities and traits ranged from 65 to 76. These THI values can be achieved with different temperature/humidity combinations with a range of temperatures from 21 to 36°C and relative humidity values from 5 to 95%. The highest negative effect of THI was observed 4 d before test day over the 3 parities for all traits. The negative effect of THI on production traits indicates that first-parity cows are less sensitive to heat stress than multiparous cows. Over the parities, the general additive genetic variance decreased for protein content and increased for milk yield and fat and protein yield. Additive genetic variance for heat tolerance showed an increase from the first to third parity for milk, protein, and fat yield, and for protein percentage. Genetic correlations between general and heat stress effects were all unfavorable (from -0.24 to -0.56). Three EBV per trait were calculated for each cow and bull (traditional EBV, traditional EBV estimated with the inclusion of THI covariate effect, and heat tolerance EBV) and the rankings of EBV for 283 bulls born after 1985 with at least 50 daughters were compared. When THI was included in the model, the ranking for 17 and 32 bulls changed for milk yield and protein percentage, respectively. The heat tolerance genetic component is not negligible, suggesting that heat tolerance selection should be included in the selection objectives. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Quantitative trait loci identified for blood chemistry components of an advanced intercross line of chickens under heat stress.

PubMed

Van Goor, Angelica; Ashwell, Christopher M; Persia, Michael E; Rothschild, Max F; Schmidt, Carl J; Lamont, Susan J

2016-04-14

Heat stress in poultry results in considerable economic losses and is a concern for both animal health and welfare. Physiological changes occur during periods of heat stress, including changes in blood chemistry components. A highly advanced intercross line, created from a broiler (heat susceptible) by Fayoumi (heat resistant) cross, was exposed to daily heat cycles for seven days starting at 22 days of age. Blood components measured pre-heat treatment and on the seventh day of heat treatment included pH, pCO2, pO2, base excess, HCO3, TCO2, K, Na, ionized Ca, hematocrit, hemoglobin, sO2, and glucose. A genome-wide association study (GWAS) for these traits and their calculated changes was conducted to identify quantitative trait loci (QTL) using a 600 K SNP panel. There were significant increases in pH, base excess, HCO3, TCO2, ionized Ca, hematocrit, hemoglobin, and sO2, and significant decreases in pCO2 and glucose after 7 days of heat treatment. Heritabilities ranged from 0.01-0.21 for pre-heat measurements, 0.01-0.23 for measurements taken during heat, and 0.00-0.10 for the calculated change due to heat treatment. All blood components were highly correlated within measurement days, but not correlated between measurement days. The GWAS revealed 61 QTL for all traits, located on GGA (Gallus gallus chromosome) 1, 3, 6, 9, 10, 12-14, 17, 18, 21-28, and Z. A functional analysis of the genes in these QTL regions identified the Angiopoietin pathway as significant. The QTL that co-localized for three or more traits were on GGA10, 22, 26, 28, and Z and revealed candidate genes for birds' response to heat stress. The results of this study contribute to our knowledge of levels and heritabilities of several blood components of chickens under thermoneutral and heat stress conditions. Most components responded to heat treatment. Mapped QTL may serve as markers for genomic selection to enhance heat tolerance in poultry. The Angiopoietin pathway is likely involved in the response to heat stress in chickens. Several candidate genes were identified, giving additional insight into potential mechanisms of physiologic response to high ambient temperatures.

Thermal analysis and optimization of the EAST ICRH antenna

NASA Astrophysics Data System (ADS)

Qingxi, YANG; Wei, SONG; Qunshan, DU; Yuntao, SONG; Chengming, QIN; Xinjun, ZHANG; Yanping, ZHAO

2018-02-01

The ion cyclotron resonance of frequency heating (ICRH) plays an important role in plasma heating. Two ICRH antennas were designed and applied on the EAST tokamak. In order to meet the requirement imposed by high-power and long-pulse operation of EAST in the future, an active cooling system is mandatory to be designed to remove the heat load deposited on the components. Thermal analyses for high heat-load components have been carried out, which presented clear temperature distribution on each component and provided the reference data to do the optimization. Meanwhile, heat pipes were designed to satisfy the high requirement imposed by a Faraday shield and lateral limiter.

Machine-learned analysis of the association of next-generation sequencing-based human TRPV1 and TRPA1 genotypes with the sensitivity to heat stimuli and topically applied capsaicin.

PubMed

Kringel, Dario; Geisslinger, Gerd; Resch, Eduard; Oertel, Bruno G; Thrun, Michael C; Heinemann, Sarah; Lötsch, Jörn

2018-03-27

Heat pain and its modulation by capsaicin varies among subjects in experimental and clinical settings. A plausible cause is a genetic component, of which TRPV1 ion channels, by their response to both heat and capsaicin, are primary candidates. However, TRPA1 channels can heterodimerize with TRPV1 channels and carry genetic variants reported to modulate heat pain sensitivity. To address the role of these candidate genes in capsaicin-induced hypersensitization to heat, pain thresholds acquired before and after topical application of capsaicin and TRPA1/TRPV1 exomic sequences derived by next-generation sequencing were assessed in n = 75 healthy volunteers and the genetic information comprised 278 loci. Gaussian mixture modeling indicated 2 phenotype groups with high or low capsaicin-induced hypersensitization to heat. Unsupervised machine learning implemented as swarm-based clustering hinted at differences in the genetic pattern between these phenotype groups. Several methods of supervised machine learning implemented as random forests, adaptive boosting, k-nearest neighbors, naive Bayes, support vector machines, and for comparison, binary logistic regression predicted the phenotype group association consistently better when based on the observed genotypes than when using a random permutation of the exomic sequences. Of note, TRPA1 variants were more important for correct phenotype group association than TRPV1 variants. This indicates a role of the TRPA1 and TRPV1 next-generation sequencing-based genetic pattern in the modulation of the individual response to heat-related pain phenotypes. When considering earlier evidence that topical capsaicin can induce neuropathy-like quantitative sensory testing patterns in healthy subjects, implications for future analgesic treatments with transient receptor potential inhibitors arise.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Susceptor heating device for electron beam brazing

DOEpatents

Antieau, Susan M.; Johnson, Robert G. R.

1999-01-01

A brazing device and method are provided which locally apply a controlled amount of heat to a selected area, within a vacuum. The device brazes two components together with a brazing metal. A susceptor plate is placed in thermal contact with one of the components. A serrated pedestal supports the susceptor plate. When the pedestal and susceptor plate are in place, an electron gun irradiates an electron beam at the susceptor plate such that the susceptor plate is sufficiently heated to transfer heat through the one component and melt the brazing metal.

Features of Afterbody Radiative Heating for Earth Entry

NASA Technical Reports Server (NTRS)

Johnston, Christopher O.; Brandis, Aaron

2014-01-01

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

Apparatus and process for the refrigeration, liquefaction and separation of gases with varying levels of purity

DOEpatents

Bingham, Dennis N.; Wilding, Bruce M.; McKellar, Michael G.

2002-01-01

A process for the separation and liquefaction of component gasses from a pressurized mix gas stream is disclosed. The process involves cooling the pressurized mixed gas stream in a heat exchanger so as to condensing one or more of the gas components having the highest condensation point; separating the condensed components from the remaining mixed gas stream in a gas-liquid separator; cooling the separated condensed component stream by passing it through an expander; and passing the cooled component stream back through the heat exchanger such that the cooled component stream functions as the refrigerant for the heat exchanger. The cycle is then repeated for the remaining mixed gas stream so as to draw off the next component gas and further cool the remaining mixed gas stream. The process continues until all of the component gases are separated from the desired gas stream. The final gas stream is then passed through a final heat exchanger and expander. The expander decreases the pressure on the gas stream, thereby cooling the stream and causing a portion of the gas stream to liquify within a tank. The portion of the gas which is hot liquefied is passed back through each of the heat exchanges where it functions as a refrigerant.

Apparatus and process for the refrigeration, liquefaction and separation of gases with varying levels of purity

DOEpatents

Bingham, Dennis N.; Wilding, Bruce M.; McKellar, Michael G.

2000-01-01

A process for the separation and liquefaction of component gasses from a pressurized mix gas stream is disclosed. The process involves cooling the pressurized mixed gas stream in a heat exchanger so as to condense one or more of the gas components having the highest condensation point; separating the condensed components from the remaining mixed gas stream in a gas-liquid separator; cooling the separated condensed component stream by passing it through an expander; and passing the cooled component stream back through the heat exchanger such that the cooled component stream functions as the refrigerant for the heat exchanger. The cycle is then repeated for the remaining mixed gas stream so as to draw off the next component gas and further cool the remaining mixed gas stream. The process continues until all of the component gases are separated from the desired gas stream. The final gas stream is then passed through a final heat exchanger and expander. The expander decreases the pressure on the gas stream, thereby cooling the stream and causing a portion of the gas stream to liquify within a tank. The portion of the gas which is not liquefied is passed back through each of the heat exchanges where it functions as a refrigerant.

Mechanisms underlying differential food allergy response to heated egg.

PubMed

Martos, Gustavo; Lopez-Exposito, Ivan; Bencharitiwong, Ramon; Berin, M Cecilia; Nowak-Węgrzyn, Anna

2011-04-01

Egg white proteins are usually subjected to heating, making them edible for the majority of children with egg allergy. We sought to investigate the underlying mechanisms responsible for the reduced allergenicity displayed by heat-treated egg white allergens. C3H/HeJ mice were orally sensitized with ovalbumin (OVA) or ovomucoid and challenged with native or heated proteins to evaluate their allergenicity. Immunoreactivity was assessed by immunoblotting using sera from children with egg allergy. In vitro gastrointestinal digestion of native and heated OVA and ovomucoid was studied by SDS-PAGE and liquid chromatography. Intestinal uptake of intact native and heated OVA and ovomucoid by human intestinal epithelial (Caco-2) cells was investigated. Rat basophil leukemia cells passively sensitized with mouse serum and human basophils passively sensitized with serum from children with egg allergy were used to assess the effector cell activation by heated, digested, and transported OVA and ovomucoid. Heated OVA and ovomucoid did not induce symptoms of anaphylaxis in sensitized mice when administered orally. Heating did not completely destroy IgE-binding capacity of OVA or ovomucoid but enhanced in vitro digestibility of OVA. Digestion of both OVA and ovomucoid diminished mediator release in rat basophil leukemia assay and basophil activation. Heating of allergens prevented transport across human intestinal epithelial cells in a form capable of triggering basophil activation or T-cell activation. Heat treatment reduces allergenicity of OVA and ovomucoid. This is partially a result of the enhanced gastrointestinal digestibility of heated OVA and the inability of heated OVA or ovomucoid to be absorbed in a form capable of triggering basophils. Copyright © 2011 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Impacts of extreme weather events and climate variability on carbon exchanges in an age-sequence of managed temperate pine forests from 2003 to 201

NASA Astrophysics Data System (ADS)

Arain, M. A.

2017-12-01

North American temperate forests are a critical component of the global carbon cycle and regional water resources. A large portion of these forests has traditionally been managed for timber production and other uses. The response of these forests, which are in different stages of development, to extreme weather events such as drought and heat stresses, climate variability and management regimes is not fully understood. In this study, eddy covariance flux measurements in an age sequence (77-, 42-, and 14-years old as of 2016) of white pine (Pinus strobus L.) plantation forests in southern Ontario, Canada are examined to determine the impact of heat and drought stresses and climate variability over a 14 year period (2003 to 2016). The mean annual net ecosystem productivity (NEP) values were 195 ± 87, 512 ±161 and 103 ± 103 g C m-2 year-1 in 77-, 42- and 14-year-old forests respectively, over the study period. The youngest forest became a net carbon sink in the fifth year of its growth. Air temperature was a dominant control on carbon fluxes and heat stress reduced photosynthesis much more as compared to ecosystem respiration in the growing season. A large decrease in annual NEP was observed during years experiencing heat waves. Drought stress had the strongest impact on the middle age forest which had the largest carbon sink and water demand. In contrast, young forest was more sensitive to heat stress, than drought. Severity of heat and drought stress impacts was highly dependent on the timing of these events. Simultaneous occurrence of heat and drought stress in the early growing season such as in 2012 and 2016 had a drastic negative impact on carbon balance in these forests due to plant-soil-atmosphere feedbacks. Future research should consider the timing of the extreme events, the stage of forest development and effects of extreme events on component fluxes. This research helps to assess the vulnerability of managed forests and their ecological and hydrological responses to climate change and extreme weather events.

Minimization of thermal impact by application of electrode cooling in a co-linear PEF treatment chamber.

PubMed

Meneses, Nicolas; Jaeger, Henry; Knorr, Dietrich

2011-10-01

A co-linear pulsed electric field (PEF) treatment chamber was analyzed and optimized considering electrical process conditions, temperature, and retention of heat-sensitive compounds during a continuous PEF treatment of peach juice. The applicability of a jacket heat-exchanger device surrounding the ground electrode was studied in order to provide active cooling and to avoid temperature peaks within the treatment chamber thus reducing the total thermal load to which the product is exposed. Simulation of the PEF process was performed using a finite element method prior to experimental verification. Inactivation of polyphenoloxydase (PPO) and peroxidase (POD) as well as the degradation of ascorbic acid (AA) in peach juice was quantified and used as indirect indicators for the temperature distribution. Peaks of product temperature within the treatment chamber were reduced, that is, from 98 to 75 °C and retention of the indicators PPO, POD, and AA increased by more than 10% after application of the active electrode cooling device. Practical Application:  The co-linear PEF treatment chamber is widely used for continuous PEF treatment of liquid products and also suitable for industrial scale application; however, Joule heating in combination with nonuniform electric field distribution may lead to unwanted thermal effects. The proposed design showed potential to reduce the thermal load, to which the food is exposed, allowing the retention of heat-sensitive components. The design is applicable at laboratory or industrial scale to perform PEF trials avoiding temperature peaks, which is also the basis for obtaining inactivation kinetic models with minimized thermal impact on the kinetic variables. © 2011 Institute of Food Technologists®

High heat flux issues for plasma-facing components in fusion reactors

NASA Astrophysics Data System (ADS)

Watson, Robert D.

1993-02-01

Plasma facing components in tokamak fusion reactors are faced with a number of difficult high heat flux issues. These components include: first wall armor tiles, pumped limiters, diverter plates, rf antennae structure, and diagnostic probes. Peak heat fluxes are 15 - 30 MW/m2 for diverter plates, which will operate for 100 - 1000 seconds in future tokamaks. Disruption heat fluxes can approach 100,000 MW/m2 for 0.1 ms. Diverter plates are water-cooled heat sinks with armor tiles brazed on to the plasma facing side. Heat sink materials include OFHC, GlidcopTM, TZM, Mo-41Re, and niobium alloys. Armor tile materials include: carbon fiber composites, beryllium, silicon carbide, tungsten, and molybdenum. Tile thickness range from 2 - 10 mm, and heat sinks are 1 - 3 mm. A twisted tape insert is used to enhance heat transfer and increase the burnout safety margin from critical heat flux limits to 50 - 60 MW/m2 with water at 10 m/s and 4 MPa. Tests using rastered electron beams have shown thermal fatigue failures from cracks at the brazed interface between tiles and the heat sink after only 1000 cycles at 10 - 15 MW/m2. These fatigue lifetimes need to be increased an order of magnitude to meet future requirements. Other critical issues for plasma facing components include: surface erosion from sputtering and disruption erosion, eddy current forces and runaway electron impact from disruptions, neutron damage, tritium retention and release, remote maintenance of radioactive components, corrosion-erosion, and loss-of-coolant accidents.

Microwave heat treating of manufactured components

DOEpatents

Ripley, Edward B.

2007-01-09

An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

Temperature-sensitive elastin-mimetic dendrimers: Effect of peptide length and dendrimer generation to temperature sensitivity.

PubMed

Kojima, Chie; Irie, Kotaro; Tada, Tomoko; Tanaka, Naoki

2014-06-01

Dendrimers are synthetic macromolecules with unique structure, which are a potential scaffold for peptides. Elastin is one of the main components of extracellular matrix and a temperature-sensitive biomacromolecule. Previously, Val-Pro-Gly-Val-Gly peptides have been conjugated to a dendrimer for designing an elastin-mimetic dendrimer. In this study, various elastin-mimetic dendrimers using different length peptides and different dendrimer generations were synthesized to control the temperature dependency. The elastin-mimetic dendrimers formed β-turn structure by heating, which was similar to the elastin-like peptides. The elastin-mimetic dendrimers exhibited an inverse phase transition, largely depending on the peptide length and slightly depending on the dendrimer generation. The elastin-mimetic dendrimers formed aggregates after the phase transition. The endothermal peak was observed in elastin-mimetic dendrimers with long peptides, but not with short ones. The peptide length and the dendrimer generation are important factors to tune the temperature dependency on the elastin-mimetic dendrimer. Copyright © 2013 Wiley Periodicals, Inc.

Ruggedizing vibration sensitive components of electro-optical module using wideband dynamic absorber

NASA Astrophysics Data System (ADS)

Veprik, Alexander; Openhaim, Yaki; Babitsky, Vladimir; Tuito, Avi

2018-05-01

In the modern design approach, the cold portion of Integrated Dewar-Detector-Cooler-Assembly (substrate, infrared focal plane array, cold shield and cold filter) is directly mounted upon the distal end of a cold finger of a cryogenic cooler with no mechanical contact with the warm Dewar shroud. This concept allows for essential reduction of parasitic (conductive) heat load. The penalty, however, is that resulting tip-mass cantilever is lightly damped and, therefore, prone to vibrational extremes typical of the modern battlefield. Without sufficient ruggedizing, vibration induced structural resonances may affect image quality and even may cause mechanical failures due to material fatigue. Use of additional front supports or thickening the cold finger walls results in increased parasitic conductive heat load, power consumption and mechanical complexity. The authors explore the concept of wideband dynamic absorber in application to ruggedizing the Integrated Dewar-Detector-Cooler Assembly.

Exploring the hidden interior of the Earth with directional neutrino measurements.

PubMed

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

2017-07-10

Roughly 40% of the Earth's total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth's radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.

Application of metallic magnetic calorimeter in rare event search

NASA Astrophysics Data System (ADS)

Kim, I.; Jo, H. S.; Kang, C. S.; Kim, G. B.; Kim, H. L.; Kim, S. R.; Kim, Y. H.; Lee, H. J.; Lee, J. H.; Lee, M. K.; Oh, S. Y.; So, J. H.

2017-09-01

Metallic magnetic calorimeters (MMCs) are highly sensitive temperature sensors that use the paramagnetic nature of erbium in a metallic host and superconducting electronics usually composed of a superconducting niobium coil and a current sensing superconducting quantum interference device. This article discusses the applicability of MMCs in experimental searches for rare events in particle physics. A detector module using two MMCs was built to perform low-temperature measurements of heat and scintillation light generated by particle interaction in a 340 g 40Ca100MoO4 crystal. The energy transfer mechanism, from incident particles to the components of the heat and light sensors, is described through a thermal model. MMCs, with gold films collecting athermal phonons, can be used over wide ranges of operating temperature and crystal volume without a significant change in detector performances. Rare event searches could thus benefit from MMC-based detectors presenting such flexibility as well as excellent energy resolution and particle discrimination power.

Design and implementation of an improved chilled water glycol system for GeMS: CANOPUS thermal enclosures

NASA Astrophysics Data System (ADS)

Gausachs, Gaston; Bec, Matthieu; Galvez, Ramon; Cavedoni, Chas; Vergara, Vicente; Diaz, Herman; Fernandez, German

2010-07-01

CANOPUS is the facility instrument for the Gemini Multi Conjugate Adaptive Optics System (GeMS) wherein all the adaptive optics mechanisms and associated electronic are tightly packed. At an early stage in the pre-commissioning phase Gemini undertook the redesign and implementation of its chilled Ethylene Glycol Water (EGW) cooling system to remove the heat generated by the electronic hardware. The electronic boards associated with the Deformable Mirrors (DM) represent the highest density heat yielding components in CANOPUS and they are also quite sensitive to overheating. The limited size of the two electronic thermal enclosures (TE) requires the use of highly efficient heat exchangers (HX) coupled with powerful yet compact DC fans. A systematic approach to comply with all the various design requirements brought about a thorough and robust solution that, in addition to the core elements (HXs and fan), makes use of features such as high performance vacuum insulated panels, vibration mitigation elements and several environment sensors. This paper describes the design and implementation of the solution in the lab prior to delivering CANOPUS for commissioning.

Utility of bromide and heat tracers for aquifer characterization affected by highly transient flow conditions

NASA Astrophysics Data System (ADS)

Ma, Rui; Zheng, Chunmiao; Zachara, John M.; Tonkin, Matthew

2012-08-01

A tracer test using both bromide and heat tracers conducted at the Integrated Field Research Challenge site in Hanford 300 Area (300A), Washington, provided an instrument for evaluating the utility of bromide and heat tracers for aquifer characterization. The bromide tracer data were critical to improving the calibration of the flow model complicated by the highly dynamic nature of the flow field. However, most bromide concentrations were obtained from fully screened observation wells, lacking depth-specific resolution for vertical characterization. On the other hand, depth-specific temperature data were relatively simple and inexpensive to acquire. However, temperature-driven fluid density effects influenced heat plume movement. Moreover, the temperature data contained "noise" caused by heating during fluid injection and sampling events. Using the hydraulic conductivity distribution obtained from the calibration of the bromide transport model, the temperature depth profiles and arrival times of temperature peaks simulated by the heat transport model were in reasonable agreement with observations. This suggested that heat can be used as a cost-effective proxy for solute tracers for calibration of the hydraulic conductivity distribution, especially in the vertical direction. However, a heat tracer test must be carefully designed and executed to minimize fluid density effects and sources of noise in temperature data. A sensitivity analysis also revealed that heat transport was most sensitive to hydraulic conductivity and porosity, less sensitive to thermal distribution factor, and least sensitive to thermal dispersion and heat conduction. This indicated that the hydraulic conductivity remains the primary calibration parameter for heat transport.

Space Shuttle Orbiter flight heating rate measurement sensitivity to thermal protection system uncertainties

NASA Technical Reports Server (NTRS)

Bradley, P. F.; Throckmorton, D. A.

1981-01-01

A study was completed to determine the sensitivity of computed convective heating rates to uncertainties in the thermal protection system thermal model. Those parameters considered were: density, thermal conductivity, and specific heat of both the reusable surface insulation and its coating; coating thickness and emittance; and temperature measurement uncertainty. The assessment used a modified version of the computer program to calculate heating rates from temperature time histories. The original version of the program solves the direct one dimensional heating problem and this modified version of The program is set up to solve the inverse problem. The modified program was used in thermocouple data reduction for shuttle flight data. Both nominal thermal models and altered thermal models were used to determine the necessity for accurate knowledge of thermal protection system's material thermal properties. For many thermal properties, the sensitivity (inaccuracies created in the calculation of convective heating rate by an altered property) was very low.

Theoretical insights into the stabilities, detonation performance, and electrostatic potentials of cocrystals containing α- or β-HMX and TATB, FOX-7, NTO, or DMF in various molar ratios.

PubMed

Song, Ken-Peng; Ren, Fu-de; Zhang, Shu-Hai; Shi, Wen-Jing

2016-10-01

A molecular dynamics method was employed to study the binding energies associated with the cocrystallization (at selected crystal planes) of either 1,3,5-triamino-2,4,6-trinitro-benzene (TATB), 1,1-diamino-2,2-dinitroethylene, 3-nitro-1,2,4-triazol-5-one (TATB, FOX-7, and NTO, respectively, all of which are explosives), or N,N-dimethylformamide (DMF, a nonenergetic solvent) in various molar ratios with 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane in its α and β conformations (α-HMX and β-HMX, respectively). The results showed that the cocrystals with low molar ratios (2:1, 1:1, 1:2, and 1:3) were the most stable. The binding energies of HMX/NTO and HMX/DMF were larger than those of HMX/TATB and HMX/FOX-7. According to the calculated stabilities, HMX prefers to adopt its α form in HMX/TATB and its β form in HMX/NTO, whereas the two forms coexist in HMX/FOX-7. For HMX/TATB, HMX/NTO, and α-HMX/FOX-7, increasing the proportion of the cocrystal component with the highest detonation heat (HMX in the first two cases, FOX-7 in the latter) increases the detonation heat, velocity, and pressure of the cocrystal. However, increasing the proportion of the component with the highest detonation heat in β-HMX/FOX-7 and γ-CL-20/FOX-7 increases the detonation heat of the cocrystal but decreases its detonation velocity. An investigation of the surface electrostatic potential revealed how the sensitivity changes upon cocrystal formation. Graphical Abstract Surface electrostatic potential of HMX/TATB.

Addressing the selectivity issue of cobalt doped zinc oxide thin film iso-butane sensors: Conductance transients and principal component analyses

NASA Astrophysics Data System (ADS)

Ghosh, A.; Majumder, S. B.

2017-07-01

Iso-butane (i-C4H10) is one of the major components of liquefied petroleum gas which is used as fuel in domestic and industrial applications. Developing chemi-resistive selective i-C4H10 thin film sensors remains a major challenge. Two strategies were undertaken to differentiate carbon monoxide, hydrogen, and iso-butane gases from the measured conductance transients of cobalt doped zinc oxide thin films. Following the first strategy, the response and recovery transients of conductances in these gas environments are fitted using the Langmuir adsorption kinetic model to estimate the heat of adsorption, response time constant, and activation energies for adsorption (response) and desorption (recovery). Although these test gases have seemingly different vapor densities, molecular diameters, and reactivities, analyzing the estimated heat of adsorption and activation energies (for both adsorption and desorption), we could not differentiate these gases unequivocally. However, we have found that the lower the vapor density, the faster the response time irrespective of the test gas concentration. As a second strategy, we demonstrated that feature extraction of conductance transients (using fast Fourier transformation) in conjunction with the pattern recognition algorithm (principal component analysis) is more fruitful to address the cross-sensitivity of Co doped ZnO thin film sensors. We have found that although the dispersion among different concentrations of hydrogen and carbon monoxide could not be avoided, each of these three gases forms distinct clusters in the plot of principal component 2 versus 1 and therefore could easily be differentiated.

The Focusing Optics X-ray Solar Imager

NASA Astrophysics Data System (ADS)

Glesener, L.; Christe, S.; Krucker, S.; Ishikawa, S.; Ramsey, B.; Takahashi, T.; Saito, S.; Lin, R. P.

2012-12-01

Measurements of the nonthermal energies and occurrence frequencies of nanoflares are important for understanding the overall flare contribution to coronal heating. Nanoflares have been observed to be ubiquitous in the quiet Sun in extreme ultraviolet and soft X-ray wavelengths, but so far remain undetected at nonthermal hard X-ray (HXR) energies, likely due to the insufficient sensitivity of current instruments. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload has been designed for high sensitivity in the 5-15 keV range by combining grazing-incidence HXR optics with fine-resolution silicon strip detectors. FOXSI will make the first measurement of nonthermal HXR from accelerated electrons in nanoflares, and will also measure hot (5-10 MK) components of active region temperatures. FOXSI is scheduled for a first flight in October 2012, and the first results of this flight will be presented.

Genome-Wide Transcriptome Analysis During Anthesis Reveals New Insights into the Molecular Basis of Heat Stress Responses in Tolerant and Sensitive Rice Varieties.

PubMed

González-Schain, Nahuel; Dreni, Ludovico; Lawas, Lovely M F; Galbiati, Massimo; Colombo, Lucia; Heuer, Sigrid; Jagadish, Krishna S V; Kater, Martin M

2016-01-01

Rice is one of the main food crops in the world. In the near future, yield is expected to be under pressure due to unfavorable climatic conditions, such as increasing temperatures. Therefore, improving rice germplasm in order to guarantee rice production under harsh environmental conditions is of top priority. Although many physiological studies have contributed to understanding heat responses during anthesis, the most heat-sensitive stage, molecular data are still largely lacking. In this study, an RNA-sequencing approach of heat- and control-treated reproductive tissues during anthesis was carried out using N22, one of the most heat-tolerant rice cultivars known to date. This analysis revealed that expression of genes encoding a number of transcription factor families, together with signal transduction and metabolic pathway genes, is repressed. On the other hand, expression of genes encoding heat shock factors and heat shock proteins was highly activated. Many of these genes are predominantly expressed at late stages of anther development. Further physiological experiments using heat-tolerant N22 and two sensitive cultivars suggest that reduced yield in heat-sensitive plants may be associated with poor pollen development or production in anthers prior to anthesis. In parallel, induction levels of a set of heat-responsive genes in these tissues correlated well with heat tolerance. Altogether, these findings suggest that proper expression of protective chaperones in anthers is needed before anthesis to overcome stress damage and to ensure fertilization. Genes putatively controlling this process were identified and are valuable candidates to consider for molecular breeding of highly productive heat-tolerant cultivars. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Dynamically limiting energy consumed by cooling apparatus

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Schmidt, Roger R.; Schultz, Mark D.

2015-06-09

Cooling methods are provided which include providing: one or more coolant-cooled structures associated with an electronics rack, a coolant loop coupled in fluid communication with one or more passages of the coolant-cooled structure(s), one or more heat exchange units coupled to facilitate heat transfer from coolant within the coolant loop, and N controllable components associated with the coolant loop or the heat exchange unit(s), wherein N.gtoreq.1. The N controllable components facilitate circulation of coolant through the coolant loop or transfer of heat from the coolant via the heat exchange unit(s). A controller is also provided to dynamically adjust operation of the N controllable components, based on Z input parameters and one or more specified constraints, and provide a specified cooling to the coolant-cooled structure(s), while limiting energy consumed by the N controllable components, wherein Z.gtoreq.1.

Sensitivities of ionic explosives

NASA Astrophysics Data System (ADS)

Politzer, Peter; Lane, Pat; Murray, Jane S.

2017-03-01

We have investigated the relevance for ionic explosive sensitivity of three factors that have been demonstrated to be related to the sensitivities of molecular explosives. These are (1) the maximum available heat of detonation, (2) the amount of free space per molecule (or per formula unit) in the crystal lattice and (3) specific features of the electrostatic potential on the molecular or ionic surface. We find that for ionic explosives, just as for molecular ones, there is an overall tendency for impact sensitivity to increase as the maximum detonation heat release is greater. This means that the usual emphasis upon designing explosives with large heats of detonation needs to be tempered somewhat. We also show that a moderate detonation heat release does not preclude a high level of detonation performance for ionic explosives, as was already demonstrated for molecular ones. Relating the free space per formula unit to sensitivity may require a modified procedure for ionic explosives; this will continue to be investigated. Finally, an encouraging start has been made in linking impact sensitivities to the electrostatic potentials on ionic surfaces, although limited so far to ammonium salts.

Apparatus with moderating material for microwave heat treatment of manufactured components

DOEpatents

Ripley, Edward B [Knoxville, TN

2011-05-10

An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

Apparatus for microwave heat treatment of manufactured components

DOEpatents

Babcock & Wilcox Technical Services Y-12, LLC

2008-04-15

An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

Methods for microwave heat treatment of manufactured components

DOEpatents

Ripley, Edward B.

2010-08-03

An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

Effect of different drying techniques on bioactive components, fatty acid composition, and volatile profile of robusta coffee beans.

PubMed

Dong, Wenjiang; Hu, Rongsuo; Chu, Zhong; Zhao, Jianping; Tan, Lehe

2017-11-01

This study investigated the effect of different drying techniques, namely, room-temperature drying (RTD), solar drying (SD), heat-pump drying (HPD), hot-air drying (HAD), and freeze drying (FD), on bioactive components, fatty acid composition, and the volatile compound profile of robusta coffee beans. The data showed that FD was an effective method to preserve fat, organic acids, and monounsaturated fatty acids. In contrast, HAD was ideal for retaining polyunsaturated fatty acids and amino acids. Sixty-two volatile compounds were identified in the differently dried coffee beans, representing 90% of the volatile compounds. HPD of the coffee beans produced the largest number of volatiles, whereas FD resulted in the highest volatile content. A principal component analysis demonstrated a close relationship between the HPD, SD, and RTD methods whereas the FD and HAD methods were significantly different. Overall, the results provide a basis for potential application to other similar thermal sensitive materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Packaging-induced failure of semiconductor lasers and optical telecommunications components

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

Sharps, J.A.

1996-12-31

Telecommunications equipment for field deployment generally have specified lifetimes of > 100,000 hr. To achieve this high reliability, it is common practice to package sensitive components in hermetic, inert gas environments. The intent is to protect components from particulate and organic contamination, oxidation, and moisture. However, for high power density 980 nm diode lasers used in optical amplifiers, the authors found that hermetic, inert gas packaging induced a failure mode not observed in similar, unpackaged lasers. They refer to this failure mode as packaging-induced failure, or PIF. PIF is caused by nanomole amounts of organic contamination which interact with highmore » intensity 980 nm light to form solid deposits over the emitting regions of the lasers. These deposits absorb 980 nm light, causing heating of the laser, narrowing of the band gap, and eventual thermal runaway. The authors have found PIF is averted by packaging with free O{sub 2} and/or a getter material that sequesters organics.« less

On the use of flat tile armour in high heat flux components

NASA Astrophysics Data System (ADS)

Merola, M.; Vieider, G.

1998-10-01

The possibility to have a flat tile geometry for those high heat flux components subjected to a convective heat flux (namely the divertor dump target, lower vertical target, and the limiter) has been investigated. Because of the glancing incidence of the power load, if an armour tile falls off an extremely high heat flux hits the leading edge of the adjacent tile. As a result a rapid temperature increase occurs in the armour-heat sink joint. The heat flux to the water coolant also increases rapidly up to a factor of 1.7 and 2.3 for a beryllium and CFC armour, respectively, thus causing possible critical heat flux problems. Thermal stresses in the armour-heat sink joint double in less than 0.4 s and triplicate after 1 s thus leading to a possible cascade failure. Therefore the use of a flat tile geometry for these components does not seem to be appropriate. In this case a monoblock geometry gives a much more robust solution.

Programmable selectivity for GC with series-coupled columns using pulsed heating of the second column.

PubMed

Whiting, Joshua; Sacks, Richard

2003-05-15

A series-coupled ensemble of a nonpolar dimethyl polysiloxane column and a polar trifluoropropylmethyl polysiloxane column with independent at-column heating is used to obtain pulsed heating of the second column. For mixture component bands that are separated by the first column but coelute from the column ensemble, a temperature pulse is initiated after the first of the two components has crossed the column junction point and is in the second column, while the other component is still in the first column. This accelerates the band for the first component. If the second column cools sufficiently prior to the second component band crossing the junction, the second band experiences less acceleration, and increased separation is observed for the corresponding peaks in the ensemble chromatogram. High-speed at-column heating is obtained by wrapping the fused-silica capillary column with resistance heater wire and sensor wire. Rapid heating for a temperature pulse is obtained with a short-duration linear heating ramp of 1000 degrees C/min. During a pulse, the second-column temperature increases by 20-100 degrees C in a few seconds. Using a cold gas environment, cooling to a quiescent temperature of 30 degrees C can be obtained in approximately 25 s. The effects of temperature pulse initiation time and amplitude on ensemble peak separation and resolution are described. A series of appropriately timed temperature pulses is used to separate three coeluting pairs of components in a 13-component mixture.

Penetration in GTA welding

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

Heiple, C.R.; Burgardt, P.

1990-01-01

The size and shape of the weld bead produced in GTA welding depends on the magnitude and distribution of the energy incident on the workpiece surfaces as well as the dissipation of that energy in the workpiece. The input energy is largely controllable through the welding parameters selected, however the dissipation of that energy in the workpiece is less subject to control. Changes in energy dissipation can produce large changes in weld shape or penetration. Heat transport away from the weld pool is almost entirely by conduction, but heat transport in the weld pool is more complicated. Heat conduction throughmore » the liquid is an important component, but heat transport by convection (mass transport) is often the dominant mechanism. Convective heat transport is directional and changes the weld pool shape from that produced by conduction alone. Surface tension gradients are often the dominant forces driving fluid flow in GTA weld pools. These gradients are sensitive functions of weld pool chemistry and the energy input distribution to the weld. Experimental and theoretical work conducted primarily in the past decade has greatly enhanced our understanding of weld pool fluid flow, the forces which drive it, and its effects on weld pool shape. This work is reviewed here. While less common, changes in energy dissipation through the unmelted portion of the workpiece can also affect fusion zone shape or penetration. These effects are also described. 41 refs., 9 figs.« less

Metabolic and transcriptomic signatures of rice floral organs reveal sugar starvation as a factor in reproductive failure under heat and drought stress.

PubMed

Li, Xia; Lawas, Lovely M F; Malo, Richard; Glaubitz, Ulrike; Erban, Alexander; Mauleon, Ramil; Heuer, Sigrid; Zuther, Ellen; Kopka, Joachim; Hincha, Dirk K; Jagadish, Krishna S V

2015-10-01

Heat and drought stress are projected to become major challenges to sustain rice (Oryza sativa L.) yields with global climate change. Both stresses lead to yield losses when they coincide with flowering. A significant knowledge gap exists in the mechanistic understanding of the responses of rice floral organs that determine reproductive success under stress. Our work connects the metabolomic and transcriptomic changes in anthers, pistils before pollination and pollinated pistils in a heat-tolerant (N22) and a heat-sensitive (Moroberekan) cultivar. Systematic analysis of the floral organs revealed contrasts in metabolic profiles across anthers and pistils. Constitutive metabolic markers were identified that can define reproductive success in rice under stress. Six out of nine candidate metabolites identified by intersection analysis of stressed anthers were differentially accumulated in N22 compared with Moroberekan under non-stress conditions. Sugar metabolism was identified to be the crucial metabolic and transcriptional component that differentiated floral organ tolerance or susceptibility to stress. While susceptible Moroberekan specifically showed high expression of the Carbon Starved Anthers (CSA) gene under combined heat and drought, tolerant N22 responded with high expression of genes encoding a sugar transporter (MST8) and a cell wall invertase (INV4) as markers of high sink strength. © 2015 John Wiley & Sons Ltd.

Utility of Bromide and Heat Tracers for Aquifer Characterization Affected by Highly Transient Flow Conditions

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

Ma, Rui; Zheng, Chunmiao; Zachara, John M.

A tracer test using both bromide and heat tracers conducted at the Integrated Field Research Challenge site in Hanford 300 Area (300A), Washington, provided an instrument for evaluating the utility of bromide and heat tracers for aquifer characterization. The bromide tracer data were critical to improving the calibration of the flow model complicated by the highly dynamic nature of the flow field. However, most bromide concentrations were obtained from fully screened observation wells, lacking depth-specific resolution for vertical characterization. On the other hand, depth-specific temperature data were relatively simple and inexpensive to acquire. However, temperature-driven fluid density effects influenced heatmore » plume movement. Moreover, the temperature data contained “noise” caused by heating during fluid injection and sampling events. Using the hydraulic conductivity distribution obtained from the calibration of the bromide transport model, the temperature depth profiles and arrival times of temperature peaks simulated by the heat transport model were in reasonable agreement with observations. This suggested that heat can be used as a cost-effective proxy for solute tracers for calibration of the hydraulic conductivity distribution, especially in the vertical direction. However, a heat tracer test must be carefully designed and executed to minimize fluid density effects and sources of noise in temperature data. A sensitivity analysis also revealed that heat transport was most sensitive to hydraulic conductivity and porosity, less sensitive to thermal distribution factor, and least sensitive to thermal dispersion and heat conduction. This indicated that the hydraulic conductivity remains the primary calibration parameter for heat transport.« less

Effect of heat treatment and enzymatic digestion on the B cell epitopes of cow's milk proteins.

PubMed

Morisawa, Y; Kitamura, A; Ujihara, T; Zushi, N; Kuzume, K; Shimanouchi, Y; Tamura, S; Wakiguchi, H; Saito, H; Matsumoto, K

2009-06-01

Processing milk leads to changes in clinical allergenicity. However, the mechanism by which heat treatment affects the allergenicity of milk proteins is not fully understood. We investigated the effect of heat treatment and enzymatic digestion on the allergenicity of B cell epitopes of milk proteins using a histamine release assay. Human basophils were passively sensitized using sera from 10 patients with allergies to cow's milk. All the patients experienced symptoms immediately after ingesting milk. The human basophils were obtained from umbilical cord blood mononuclear cells after culturing the mononuclear cells for 3-4 weeks in the presence of IL-3. After sensitization with 10% patient sera for 48 h, the cells were stimulated with untreated, heat-treated, or heat-treated and pepsin-and-trypsin-digested beta-lactoglobulin or alpha-casein for 1 h. The histamine concentrations in the supernatants were then measured by radioimmunoassay. Heat treatment alone did not alter the molecular weight of beta-lactoglobulin or alpha-casein. Heat treatment of beta-lactoglobulin significantly increased its susceptibility to enzymatic digestion in a time- and temperature-dependent manner and reduced its ability to induce histamine release from sensitized basophils. Similar findings were not observed for alpha-casein. The combination of heat treatment and enzymatic digestion reduced the abilities of both beta-lactoglobulin and alpha-casein to induce histamine release from passively sensitized basophils. Heat treatment reduced the allergenicity of beta-lactoglobulin by inducing conformational changes and by increasing its susceptibility to enzymatic digestion, both of which disrupted B cell epitopes, whereas heat treatment alone did not alter the allergenicity of alpha-casein.

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.

MJO Signals in Latent Heating: Results from TRMM Retrievals

NASA Technical Reports Server (NTRS)

Zhang, Chidong; Ling, Jian; Hagos, Samson; Tao, Wei-Kuo; Lang, Steve; Takayabu, Yukari N.; Shige, Shoichi; Katsumata, Masaki; Olson, William S.; L'Ecuyer, Tristan

2010-01-01

The Madden-Julian Oscillation (MJO) is the dominant intraseasonal signal in the global tropical atmosphere. Almost all numerical climate models have difficulty to simulate realistic MJO. Four TRMM datasets of latent heating were diagnosed for signals in the MJO. In all four datasets, vertical structures of latent heating are dominated by two components, one deep with its peak above the melting level and one shallow with its peak below. Profiles of the two components are nearly ubiquitous in longitude, allowing a separation of the vertical and zonal/temporal variations when the latitudinal dependence is not considered. All four datasets exhibit robust MJO spectral signals in the deep component as eastward propagating spectral peaks centered at period of 50 days and zonal wavenumber 1, well distinguished from lower- and higher-frequency power and much stronger than the corresponding westward power. The shallow component shows similar but slightly less robust MJO spectral peaks. MJO signals were further extracted from a combination of band-pass (30 - 90 day) filtered deep and shallow components. Largest amplitudes of both deep and shallow components of the MJO are confined to the Indian and western Pacific Oceans. There is a local minimum in the deep components over the Maritime Continent. The shallow components of the MJO differ substantially among the four TRMM datasets in their detailed zonal distributions in the eastern hemisphere. In composites of the heating evolution through the life cycle of the MJO, the shallow components lead the deep ones in some datasets and at certain longitudes. In many respects, the four TRMM datasets agree well in their deep components, but not in their shallow components and the phase relations between the deep and shallow components. These results indicate that caution must be exercised in applications of these latent heating data.

Analysis of transient receptor potential ankyrin 1 (TRPA1) in frogs and lizards illuminates both nociceptive heat and chemical sensitivities and coexpression with TRP vanilloid 1 (TRPV1) in ancestral vertebrates.

PubMed

Saito, Shigeru; Nakatsuka, Kazumasa; Takahashi, Kenji; Fukuta, Naomi; Imagawa, Toshiaki; Ohta, Toshio; Tominaga, Makoto

2012-08-31

Transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (V1) perceive noxious temperatures and chemical stimuli and are involved in pain sensation in mammals. Thus, these two channels provide a model for understanding how different genes with similar biological roles may influence the function of one another during the course of evolution. However, the temperature sensitivity of TRPA1 in ancestral vertebrates and its evolutionary path are unknown as its temperature sensitivities vary among different vertebrate species. To elucidate the functional evolution of TRPA1, TRPA1s of the western clawed (WC) frogs and green anole lizards were characterized. WC frog TRPA1 was activated by heat and noxious chemicals that activate mammalian TRPA1. These stimuli also activated native sensory neurons and elicited nocifensive behaviors in WC frogs. Similar to mammals, TRPA1 was functionally co-expressed with TRPV1, another heat- and chemical-sensitive nociceptive receptor, in native sensory neurons of the WC frog. Green anole TRPA1 was also activated by heat and noxious chemical stimulation. These results suggest that TRPA1 was likely a noxious heat and chemical receptor and co-expressed with TRPV1 in the nociceptive sensory neurons of ancestral vertebrates. Conservation of TRPV1 heat sensitivity throughout vertebrate evolution could have changed functional constraints on TRPA1 and influenced the functional evolution of TRPA1 regarding temperature sensitivity, whereas conserving its noxious chemical sensitivity. In addition, our results also demonstrated that two mammalian TRPA1 inhibitors elicited different effect on the TRPA1s of WC frogs and green anoles, which can be utilized to clarify the structural bases for inhibition of TRPA1.

Analysis of Transient Receptor Potential Ankyrin 1 (TRPA1) in Frogs and Lizards Illuminates Both Nociceptive Heat and Chemical Sensitivities and Coexpression with TRP Vanilloid 1 (TRPV1) in Ancestral Vertebrates*

PubMed Central

Saito, Shigeru; Nakatsuka, Kazumasa; Takahashi, Kenji; Fukuta, Naomi; Imagawa, Toshiaki; Ohta, Toshio; Tominaga, Makoto

2012-01-01

Transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (V1) perceive noxious temperatures and chemical stimuli and are involved in pain sensation in mammals. Thus, these two channels provide a model for understanding how different genes with similar biological roles may influence the function of one another during the course of evolution. However, the temperature sensitivity of TRPA1 in ancestral vertebrates and its evolutionary path are unknown as its temperature sensitivities vary among different vertebrate species. To elucidate the functional evolution of TRPA1, TRPA1s of the western clawed (WC) frogs and green anole lizards were characterized. WC frog TRPA1 was activated by heat and noxious chemicals that activate mammalian TRPA1. These stimuli also activated native sensory neurons and elicited nocifensive behaviors in WC frogs. Similar to mammals, TRPA1 was functionally co-expressed with TRPV1, another heat- and chemical-sensitive nociceptive receptor, in native sensory neurons of the WC frog. Green anole TRPA1 was also activated by heat and noxious chemical stimulation. These results suggest that TRPA1 was likely a noxious heat and chemical receptor and co-expressed with TRPV1 in the nociceptive sensory neurons of ancestral vertebrates. Conservation of TRPV1 heat sensitivity throughout vertebrate evolution could have changed functional constraints on TRPA1 and influenced the functional evolution of TRPA1 regarding temperature sensitivity, whereas conserving its noxious chemical sensitivity. In addition, our results also demonstrated that two mammalian TRPA1 inhibitors elicited different effect on the TRPA1s of WC frogs and green anoles, which can be utilized to clarify the structural bases for inhibition of TRPA1. PMID:22791718

Evaluation of sodium benzoate and licorice (Glycyrrhiza glabra) root extract as heat-sensitizing additives against Escherichia coli O157:H7 in mildly heated young coconut liquid endosperm.

PubMed

Gabriel, A A; Salazar, S K P

2014-08-01

This study evaluated the use of sodium benzoate (SB) and licorice root extract (LRE) as heat-sensitizing additives against Escherichia coli O157:H7 in mildly heated young coconut liquid endosperm. Consumer acceptance scoring showed that maximum permissible supplementation (MPS) levels for SB and LRE were at 300 and 250 ppm, respectively. The MPS values were considered in the generation of a 2-factor rotatable central composite design for the tested SB and LRE concentration combinations. Liquid endosperm with various SB and LRE supplementation combinations was inoculated with E. coli O157:H7 and heated to 55°C. The susceptibility of the cells towards heating was expressed in terms of the decimal reduction time (D55 ). Response surface analysis showed that only the individual linear effect of benzoate significantly influenced D55 value, where increasing supplementation level resulted in increasing susceptibility. The results reported could serve as baseline information in further investigating other additives that could be used as heat-sensitizing agents against pathogens in heat-labile food systems. Fruit juice products have been linked to outbreaks of microbial infection, where unpasteurized products were proven vectors of diseases. Processors often opt not to apply heat process to juice products as the preservation technique often compromises the sensorial quality. This work evaluated two common additives for their heat-sensitizing effects against E. coli O157:H7 in coconut liquid endosperm, the results of which may serve as baseline information to small- and medium-scale processors, and researchers in the establishment of mild heat process schedule for the test commodity and other similar products. © 2014 The Society for Applied Microbiology.

Sensing the heat with TRPM3.

PubMed

Vriens, Joris; Voets, Thomas

2018-05-01

Heat sensation, the ability to detect warm and noxious temperatures, is an ancient and indispensable sensory process. Noxious temperatures can have detrimental effects on the physiology and integrity of cells, and therefore, the detection of environmental hot temperatures is absolutely crucial for survival. Temperature-sensitive ion channels, which conduct ions in a highly temperature-dependent manner, have been put forward as molecular thermometers expressed at the endings of sensory neurons. In particular, several temperature-sensitive members of the transient receptor potential (TRP) superfamily of ion channels have been identified, and a multitude of in vivo studies have shown that the capsaicin-sensitive TRPV1 channel plays a key role as a noxious heat sensor. However, Trpv1-deficient mice display a residual heat sensitivity suggesting the existence of additional heat sensor(s). In this chapter, we provide evidence for the role of the non-selective calcium-permeable TRPM3 ion channel as an additional heat sensor that acts independently of TRPV1, and give an update of the modulation of this channel by various molecular mechanisms. Finally, we compare antagonists of TRPM3 to specific blockers of TRPV1 as potential analgesic drugs to treat pathological pain.

TRPA1 Channels in Drosophila and Honey Bee Ectoparasitic Mites Share Heat Sensitivity and Temperature-Related Physiological Functions

PubMed Central

Peng, Guangda; Kashio, Makiko; Li, Tianbang; Dong, Xiaofeng; Tominaga, Makoto; Kadowaki, Tatsuhiko

2016-01-01

The transient receptor potential cation channel, subfamily A, member 1 (TRPA1) is conserved between many arthropods, and in some has been shown to function as a chemosensor for noxious compounds. Activation of arthropod TRPA1 channels by temperature fluctuations has been tested in only a few insect species, and all of them were shown to be activated by heat. The recent identification of chemosensitive TRPA1 channels from two honey bee ectoparasitic mite species (VdTRPA1 and TmTRPA1) have provided an opportunity to study the temperature-dependent activation and the temperature-associated physiological functions of TRPA1 channels in non-insect arthropods. We found that both mite TRPA1 channels are heat sensitive and capable of rescuing the temperature-related behavioral defects of a Drosophila melanogaster trpA1 mutant. These results suggest that heat-sensitivity of TRPA1 could be conserved between many arthropods despite its amino acid sequence diversity. Nevertheless, the ankyrin repeats (ARs) 6 and 7 are well-conserved between six heat-sensitive arthropod TRPA1 channels and have critical roles for the heat activation of VdTRPA1. PMID:27761115

Heat pulse excitability of vestibular hair cells and afferent neurons

PubMed Central

Brichta, Alan M.; Tabatabaee, Hessam; Boutros, Peter J.; Ahn, JoongHo; Della Santina, Charles C.; Poppi, Lauren A.; Lim, Rebecca

2016-01-01

In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT. An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at −68 mV and in 67% of hair cells at −60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability. PMID:27226448

Integration of Decentralized Thermal Storages Within District Heating (DH) Networks

NASA Astrophysics Data System (ADS)

Schuchardt, Georg K.

2016-12-01

Thermal Storages and Thermal Accumulators are an important component within District Heating (DH) systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized) and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

Method of using infrared radiation for assembling a first component with a second component

DOEpatents

Sikka, Vinod K.; Whitson, Barry G.; Blue, Craig A.

1999-01-01

A method of assembling a first component for assembly with a second component involves a heating device which includes an enclosure having a cavity for inserting a first component. An array of infrared energy generators is disposed within the enclosure. At least a portion of the first component is inserted into the cavity, exposed to infrared energy and thereby heated to a temperature wherein the portion of the first component is sufficiently softened and/or expanded for assembly with a second component.

Sensitivity Equation Derivation for Transient Heat Transfer Problems

NASA Technical Reports Server (NTRS)

Hou, Gene; Chien, Ta-Cheng; Sheen, Jeenson

2004-01-01

The focus of the paper is on the derivation of sensitivity equations for transient heat transfer problems modeled by different discretization processes. Two examples will be used in this study to facilitate the discussion. The first example is a coupled, transient heat transfer problem that simulates the press molding process in fabrication of composite laminates. These state equations are discretized into standard h-version finite elements and solved by a multiple step, predictor-corrector scheme. The sensitivity analysis results based upon the direct and adjoint variable approaches will be presented. The second example is a nonlinear transient heat transfer problem solved by a p-version time-discontinuous Galerkin's Method. The resulting matrix equation of the state equation is simply in the form of Ax = b, representing a single step, time marching scheme. A direct differentiation approach will be used to compute the thermal sensitivities of a sample 2D problem.

US-Japan workshop Q-181 on high heat flux components and plasma-surface interactions for next devices: Proceedings

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

McGrath, R.T.; Yamashina, T.

This report contain viewgraphs of papers from the following sessions: plasma facing components issues for future machines; recent PMI results from several tokamaks; high heat flux technology; plasma facing components design and applications; plasma facing component materials and irradiation damage; boundary layer plasma; plasma disruptions; conditioning and tritium; and erosion/redeposition.

Investigation of Body Force Effects on Flow Boiling Critical Heat Flux

NASA Technical Reports Server (NTRS)

Zhang, Hui; Mudawar, Issam; Hasan, Mohammad M.

2002-01-01

The bubble coalescence and interfacial instabilities that are important to modeling critical heat flux (CHF) in reduced-gravity systems can be sensitive to even minute body forces. Understanding these complex phenomena is vital to the design and safe implementation of two-phase thermal management loops proposed for space and planetary-based thermal systems. While reduced gravity conditions cannot be accurately simulated in 1g ground-based experiments, such experiments can help isolate the effects of the various forces (body force, surface tension force and inertia) which influence flow boiling CHF. In this project, the effects of the component of body force perpendicular to a heated wall were examined by conducting 1g flow boiling experiments at different orientations. FC-72 liquid was boiled along one wall of a transparent rectangular flow channel that permitted photographic study of the vapor-liquid interface at conditions approaching CHF. High-speed video imaging was employed to capture dominant CHF mechanisms. Six different CHF regimes were identified: Wavy Vapor Layer, Pool Boiling, Stratification, Vapor Counterflow, Vapor Stagnation, and Separated Concurrent Vapor Flow. CHF showed great sensitivity to orientation for flow velocities below 0.2 m/s, where very small CHF values where measured, especially with downflow and downward-facing heated wall orientations. High flow velocities dampened the effects of orientation considerably. Figure I shows representative images for the different CHF regimes. The Wavy Vapor Layer regime was dominant for all high velocities and most orientations, while all other regimes were encountered at low velocities, in the downflow and/or downward-facing heated wall orientations. The Interfacial Lift-off model was modified to predict the effects of orientation on CHF for the dominant Wavy Vapor Layer regime. The photographic study captured a fairly continuous wavy vapor layer travelling along the heated wall while permitting liquid contact only in wetting fronts, located in the troughs of the interfacial waves. CHF commenced when wetting fronts near the outlet were lifted off the wall. The Interfacial Lift-off model is shown to be an effective tool for predicting the effects of body force on CHF at high velocities.

Operant conditioning of enhanced pain sensitivity by heat-pain titration.

PubMed

Becker, Susanne; Kleinböhl, Dieter; Klossika, Iris; Hölzl, Rupert

2008-11-15

Operant conditioning mechanisms have been demonstrated to be important in the development of chronic pain. Most experimental studies have investigated the operant modulation of verbal pain reports with extrinsic reinforcement, such as verbal reinforcement. Whether this reflects actual changes in the subjective experience of the nociceptive stimulus remained unclear. This study replicates and extends our previous demonstration that enhanced pain sensitivity to prolonged heat-pain stimulation could be learned in healthy participants through intrinsic reinforcement (contingent changes in nociceptive input) independent of verbal pain reports. In addition, we examine whether different magnitudes of reinforcement differentially enhance pain sensitivity using an operant heat-pain titration paradigm. It is based on the previously developed non-verbal behavioral discrimination task for the assessment of sensitization, which uses discriminative down- or up-regulation of stimulus temperatures in response to changes in subjective intensity. In operant heat-pain titration, this discriminative behavior and not verbal pain report was contingently reinforced or punished by acute decreases or increases in heat-pain intensity. The magnitude of reinforcement was varied between three groups: low (N1=13), medium (N2=11) and high reinforcement (N3=12). Continuous reinforcement was applied to acquire and train the operant behavior, followed by partial reinforcement to analyze the underlying learning mechanisms. Results demonstrated that sensitization to prolonged heat-pain stimulation was enhanced by operant learning within 1h. The extent of sensitization was directly dependent on the received magnitude of reinforcement. Thus, operant learning mechanisms based on intrinsic reinforcement may provide an explanation for the gradual development of sustained hypersensitivity during pain that is becoming chronic.

Why Was Silcrete Heat-Treated in the Middle Stone Age? An Early Transformative Technology in the Context of Raw Material Use at Mertenhof Rock Shelter, South Africa.

PubMed

Schmidt, Patrick; Mackay, Alex

2016-01-01

People heat treated silcrete during the Middle Stone Age (MSA) in southern Africa but the spatial and temporal variability of this practice remains poorly documented. This paucity of data in turn makes it difficult to interrogate the motive factors underlying the application of this technique. In this paper we present data on heat treatment of silcrete through the Howiesons Poort and post-Howiesons Poort of the rock shelter site Mertenhof, located in the Western Cape of South Africa. In contrast to other sites where heat treatment has been documented, distance to rock source at Mertenhof can be reasonably well estimated, and the site is known to contain high proportions of a diversity of fine grained rocks including silcrete, hornfels and chert at various points through the sequence. Our results suggest the prevalence of heat treatment is variable through the sequence but that it is largely unaffected by the relative abundance of silcrete prevalence. Instead there is a strong inverse correlation between frequency of heat treatment in silcrete and prevalence of chert in the assemblage, and a generally positive correlation with the proportion of locally available rock. While it is difficult to separate individual factors we suggest that, at Mertenhof at least, heat treatment may have been used to improve the fracture properties of silcrete at times when other finer grained rocks were less readily available. As such, heat treatment appears to have been a component of the MSA behavioural repertoire that was flexibly deployed in ways sensitive to other elements of technological organisation.

Synfuel production in nuclear reactors

DOEpatents

Henning, C.D.

Apparatus and method for producing synthetic fuels and synthetic fuel components by using a neutron source as the energy source, such as a fusion reactor. Neutron absorbers are disposed inside a reaction pipe and are heated by capturing neutrons from the neutron source. Synthetic fuel feedstock is then placed into contact with the heated neutron absorbers. The feedstock is heated and dissociates into its constituent synfuel components, or alternatively is at least preheated sufficiently to use in a subsequent electrolysis process to produce synthetic fuels and synthetic fuel components.

Suppression of cognitive function in hyperthermia; From the viewpoint of executive and inhibitive cognitive processing

NASA Astrophysics Data System (ADS)

Shibasaki, Manabu; Namba, Mari; Oshiro, Misaki; Kakigi, Ryusuke; Nakata, Hiroki

2017-03-01

Climate change has had a widespread impact on humans and natural systems. Heat stroke is a life-threatening condition in severe environments. The execution or inhibition of decision making is critical for survival in a hot environment. We hypothesized that, even with mild heat stress, not only executive processing, but also inhibitory processing may be impaired, and investigated the effectiveness of body cooling approaches on these processes using the Go/No-go task with electroencephalographic event-related potentials. Passive heat stress increased esophageal temperature (Tes) by 1.30 ± 0.24 °C and decreased cerebral perfusion and thermal comfort. Mild heat stress reduced the amplitudes of the Go-P300 component (i.e. execution) and No-go-P300 component (i.e. inhibition). Cerebral perfusion and thermal comfort recovered following face/head cooling, however, the amplitudes of the Go-P300 and No-go-P300 components remained reduced. During whole-body cooling, the amplitude of the Go-P300 component returned to the pre-heat baseline, whereas that of the No-go-P300 component remained reduced. These results suggest that local cooling of the face and head does not restore impaired cognitive processing during mild heat stress, and response inhibition remains impaired despite the return to normothermia.

AMOC sensitivity to surface buoyancy fluxes: Stronger ocean meridional heat transport with a weaker volume transport?

NASA Astrophysics Data System (ADS)

Sévellec, Florian; Fedorov, Alexey V.

2016-09-01

Oceanic northward heat transport is commonly assumed to be positively correlated with the Atlantic meridional overturning circulation (AMOC). For example, in numerical "water-hosing" experiments, imposing anomalous freshwater fluxes in the northern Atlantic leads to a slow-down of the AMOC and the corresponding reduction of oceanic northward heat transport. Here, we study the sensitivity of the ocean heat and volume transports to surface heat and freshwater fluxes using a generalized stability analysis. For the sensitivity to surface freshwater fluxes, we find that, while the direct relationship between the AMOC volume and heat transports holds on shorter time scales, it can reverse on timescales longer than 500 years or so. That is, depending on the model surface boundary conditions, reduction in the AMOC volume transport can potentially lead to a stronger heat transport on long timescales, resulting from the gradual increase in ocean thermal stratification. We discuss the implications of these results for the problem of steady state (statistical equilibrium) in ocean and climate GCM as well as paleoclimate problems including millennial climate variability.

AMOC sensitivity to surface buoyancy fluxes: Stronger ocean meridional heat transport with a weaker volume transport?

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

Sevellec, Florian; Fedorov, Alexey V.

Oceanic northward heat transport is commonly assumed to be positively correlated with the Atlantic meridional overturning circulation (AMOC). For example, in numerical "water-hosing" experiments, imposing anomalous freshwater fluxes in the northern Atlantic leads to a slow-down of the AMOC and the corresponding reduction of oceanic northward heat transport. Here, we study the sensitivity of the ocean heat and volume transports to surface heat and freshwater fluxes using a generalized stability analysis. For the sensitivity to surface freshwater fluxes, we find that, while the direct relationship between the AMOC volume and heat transports holds on shorter time scales, it can reversemore » on timescales longer than 500 years or so. That is, depending on the model surface boundary conditions, reduction in the AMOC volume transport can potentially lead to a stronger heat transport on long timescales, resulting from the gradual increase in ocean thermal stratification. Finally, we discuss the implications of these results for the problem of steady state (statistical equilibrium) in ocean and climate GCM as well as paleoclimate problems including millennial climate variability.« less

AMOC sensitivity to surface buoyancy fluxes: Stronger ocean meridional heat transport with a weaker volume transport?

DOE PAGES

Sevellec, Florian; Fedorov, Alexey V.

2016-01-04

Oceanic northward heat transport is commonly assumed to be positively correlated with the Atlantic meridional overturning circulation (AMOC). For example, in numerical "water-hosing" experiments, imposing anomalous freshwater fluxes in the northern Atlantic leads to a slow-down of the AMOC and the corresponding reduction of oceanic northward heat transport. Here, we study the sensitivity of the ocean heat and volume transports to surface heat and freshwater fluxes using a generalized stability analysis. For the sensitivity to surface freshwater fluxes, we find that, while the direct relationship between the AMOC volume and heat transports holds on shorter time scales, it can reversemore » on timescales longer than 500 years or so. That is, depending on the model surface boundary conditions, reduction in the AMOC volume transport can potentially lead to a stronger heat transport on long timescales, resulting from the gradual increase in ocean thermal stratification. Finally, we discuss the implications of these results for the problem of steady state (statistical equilibrium) in ocean and climate GCM as well as paleoclimate problems including millennial climate variability.« less

Corrosion behavior of sensitized duplex stainless steel.

PubMed

Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

1998-01-01

The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

An inexpensive economical solar heating system for homes

NASA Technical Reports Server (NTRS)

Allred, J. W.; Shinn, J. M., Jr.; Kirby, C. E.; Barringer, S. R.

1976-01-01

A low-cost solar home heating system to supplement existing warm-air heating systems is described. The report is written in three parts: (1) a brief background on solar heating, (2) experience with a demonstration system, and (3) information for the homeowner who wishes to construct such a system. Instructions are given for a solar heating installation in which the homeowner supplies all labor necessary to install off-the-shelf components estimated to cost $2,000. These components, which include solar collector, heat exchanger, water pump, storage tank, piping, and controls to make the system completely automatic, are available at local lumber yards, hardware stores, and plumbing supply stores, and are relatively simple to install. Manufacturers and prices of each component used and a rough cost analysis based on these prices are included. This report also gives performance data obtained from a demonstration system which was built and tested at the Langley Research Center.

The use of processes evaporation and condensation to provide a suitable operating environment of systems

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

Kolková, Zuzana, E-mail: zuzana.kolkova@rc.uniza.sk; Holubčík, Michal, E-mail: michal.holubcik@fstroj.uniza.sk; Malcho, Milan, E-mail: milan.malcho@fstroj.uniza.sk

All electronic components which exhibit electrical conductor resistance, generates heat when electricity is passed (Joule - Lenz’s Law). The generated heat is necessary to take into surrounding environment. To reduce the operating temperature of electronic components are used various types of cooling in electronic devices. The released heat is removed from the outside of the device in several ways, either alone or in combination. Intensification of cooling electronic components is in the use of heat transfer through phase changes. From the structural point of view it is important to create a cooling system which would be able to drain themore » waste heat converter for each mode of operation device. Another important criterion is the reliability of the cooling, and it is appropriate to choose cooling system, which would not contain moving elements. In this article, the issue tackled by the phase change in the heat pipe.« less

The use of processes evaporation and condensation to provide a suitable operating environment of systems

NASA Astrophysics Data System (ADS)

Kolková, Zuzana; Holubčík, Michal; Malcho, Milan

2016-06-01

All electronic components which exhibit electrical conductor resistance, generates heat when electricity is passed (Joule - Lenz's Law). The generated heat is necessary to take into surrounding environment. To reduce the operating temperature of electronic components are used various types of cooling in electronic devices. The released heat is removed from the outside of the device in several ways, either alone or in combination. Intensification of cooling electronic components is in the use of heat transfer through phase changes. From the structural point of view it is important to create a cooling system which would be able to drain the waste heat converter for each mode of operation device. Another important criterion is the reliability of the cooling, and it is appropriate to choose cooling system, which would not contain moving elements. In this article, the issue tackled by the phase change in the heat pipe.

Diagnostic accuracy, risk assessment, and cost-effectiveness of component-resolved diagnostics for food allergy: A systematic review.

PubMed

Flores Kim, J; McCleary, N; Nwaru, B I; Stoddart, A; Sheikh, A

2018-01-10

Component-resolved diagnostics (CRD) are promising tools for diagnosing food allergy, offering the potential to determine specific phenotypes and to develop patient-tailored risk profiles. Nevertheless, the diagnostic accuracy of these tests varies across studies; thus, their clinical utility remains unclear. Therefore, we synthesized the evidence from studies investigating the diagnostic accuracy, risk assessment ability, and cost-effectiveness of CRD for food allergy. We systematically searched 10 electronic databases and four clinical trial registries for studies published from January 2000 to February 2017. The quality of included studies was assessed using QUADAS-2. Due to heterogeneity, we narratively synthesized the evidence. Eleven studies met inclusion criteria, altogether recruiting 1098 participants. The food allergies investigated were cow's milk, hen's egg, peanut, hazelnut, and shrimp. The components with the highest diagnostic accuracy for each allergen, along with their sensitivity-specificity pairs, were as follows: Bos d 4 for cow's milk (62.0% and 87.5%), Gal d 1 for hen's egg (84.2% and 89.8% for heated egg, and 60.6% and 97.1% for raw egg), Ara h 6 for peanut (94.9% and 95.1%), Cor a 14 for hazelnut (100% and 93.8%), and Lit v 1 for shrimp (82.8% and 56.3%) allergy. Selected components of cow's milk, hen's egg, peanut, hazelnut, and shrimp allergen showed high specificity, but lower sensitivity. However, few studies exist for each component, and studies vary widely regarding the cutoff values used, making it challenging to synthesize findings across studies. Further research is needed to determine clinically appropriate cutoff values, risk assessment abilities, and cost-effectiveness of CRD approaches. © 2018 The Authors. Allergy Published by John Wiley & Sons Ltd.

The Role of Deformation and Microchemistry in the Corrosion Processes of Type 304 Stainless Steel in Simulated Pressurized Water Reactor Environments

NASA Astrophysics Data System (ADS)

Fisher, Kevin B.

Degradation of structural components in nuclear environments is a limiting factor in the lifetime of nuclear power plants. Despite decades of research on the topic, there are still aspects of the degradation phenomena that are not well understood, leading to premature failure of components that can be both expensive to repair and potentially dangerous. The current work addresses the role of material deformation on the corrosion phenomena of 304 SS in a simulated nuclear reactor environment by studying the relationship of the material microstructure and microchemistry with the resulting corrosion products using a multiscale analysis approach. The general corrosion phenomenon was studied in relation to the surface deformation of the material, and it was determined that surface deformation not only increases the rate of oxidation, but also has a pronounced impact on the microchemical structure of the oxide film when compared to undeformed material. These findings were applied to understanding the role of deformation in the more complex corrosion phenomena of stress corrosion cracking (SCC) and corrosion fatigue cracking (CFC). In SCC experiments, material deformation in the form of cold work played a synergistic role with unique microchemical features of the materials studied to promote the cracking process under certain environmental and material heat treatment conditions. Despite the fact that the materials studied were low carbon heats of 304L SS thought to be immune to the sensitization and therefore resistant to SCC, elevated boron and delta ferrites in the material were implicated in the SCC susceptibility after heat treatment. On the other hand, low levels of residual deformation played only a minor role in the corrosion processes occurring during CFC experiments over a wide range of rise times. Instead, deformation was suspected to play a larger role in the mechanical cracking response of the material. By studying multiple corrosion processes of 304 SS a greater understanding of the role of deformation and microchemical factors in the related corrosion phenomena has been achieved, and provides evidence that material and component fabrication, in terms of surface and bulk deformation, material microchemistry, and heat treatment must be considered to avoid degradation issues.

Directly connected heat exchanger tube section and coolant-cooled structure

DOEpatents

Chainer, Timothy J.; Coico, Patrick A.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

2015-09-15

A method is provided for fabricating a cooling apparatus for cooling an electronics rack, which includes an air-to-liquid heat exchanger, one or more coolant-cooled structures, and a tube. The heat exchanger is associated with the electronics rack and disposed to cool air passing through the rack, includes a plurality of coolant-carrying tube sections, each tube section having a coolant inlet and outlet, one of which is coupled in fluid communication with a coolant loop to facilitate flow of coolant through the tube section. The coolant-cooled structure(s) is in thermal contact with an electronic component(s) of the rack, and facilitates transfer of heat from the component(s) to the coolant. The tube connects in fluid communication one coolant-cooled structure and the other of the coolant inlet or outlet of the one tube section, and facilitates flow of coolant directly between that coolant-carrying tube section of the heat exchanger and the coolant-cooled structure.

Directly connected heat exchanger tube section and coolant-cooled structure

DOEpatents

Chainer, Timothy J; Coico, Patrick A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

2014-04-01

A cooling apparatus for an electronics rack is provided which includes an air-to-liquid heat exchanger, one or more coolant-cooled structures and a tube. The heat exchanger, which is associated with the electronics rack and disposed to cool air passing through the rack, includes a plurality of distinct, coolant-carrying tube sections, each tube section having a coolant inlet and a coolant outlet, one of which is coupled in fluid communication with a coolant loop to facilitate flow of coolant through the tube section. The coolant-cooled structure(s) is in thermal contact with an electronic component(s) of the rack, and facilitates transfer of heat from the component(s) to the coolant. The tube connects in fluid communication one coolant-cooled structure and the other of the coolant inlet or outlet of the one tube section, and facilitates flow of coolant directly between that coolant-carrying tube section of the heat exchanger and the coolant-cooled structure.

Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

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

Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.

Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface tomore » be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less

Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

DOEpatents

Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

2016-08-09

Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

DOEpatents

Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

2016-04-05

Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

Scanning tone burst eddy-current thermography (S-TBET) for NDT of carbon fiber reinforced plastic (CFRP) components

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

Libin, M. N.; Maxfield, B. W.; Balasubramanian, Krishnan

2014-02-18

Tone Burst Eddy Current technique uses eddy current to apply transient heating inside a component and uses a conventional IR camera for visualization of the response to the transient heating. This technique has been earliest demonstrated for metallic components made of AL, Steel, Stainless Steel, etc., and for detection of cracks, corrosion and adhesive dis-bonds. Although, not nearly as conducting as metals, the Carbon Fibre Reinforced Plastic (CFRP) material absorbs measurable electromagnetic radiation in the frequency range above 10 kHz. When the surface temperature is observed on the surface that is being heated (defined as the surface just beneath andmore » slightly to one side of the heating coil), the surface temperature increases with increasing frequency because the internal heating increases with frequency. A 2-D anisotropic transient Eddy current heating and thermal conduction model has been developed that provides a reasonable description of the processes described above. The inherent anisotropy of CFRP laminates is included in this model by calculating the heating due to three superimposed, tightly coupled isotropic layers having a specified ply-layup. The experimental apparatus consists of an induction heating coil and an IR camera with low NETD and high frame rates. The coil is moved over the sample using a stepper motor controlled manipulator. The IR data recording is synchronized with the motion control to provide a movie of the surface temperature over time. Several components were evaluated for detection of impact damage, location of stiffeners, etc. on CFRP components.« less

Nanocrystalline SiC film thermistors for cryogenic applications

NASA Astrophysics Data System (ADS)

Mitin, V. F.; Kholevchuk, V. V.; Semenov, A. V.; Kozlovskii, A. A.; Boltovets, N. S.; Krivutsa, V. A.; Slepova, A. S.; Novitskii, S. V.

2018-02-01

We developed a heat-sensitive material based on nanocrystalline SiC films obtained by direct deposition of carbon and silicon ions onto sapphire substrates. These SiC films can be used for resistance thermometers operating in the 2 K-300 K temperature range. Having high heat sensitivity, they are relatively low sensitive to the magnetic field. The designs of the sensors are presented together with a discussion of their thermometric characteristics and sensitivity to magnetic fields.

Rice Fertilization-Independent Endosperm1 Regulates Seed Size under Heat Stress by Controlling Early Endosperm Development1[W

PubMed Central

Folsom, Jing J.; Begcy, Kevin; Hao, Xiaojuan; Wang, Dong; Walia, Harkamal

2014-01-01

Although heat stress reduces seed size in rice (Oryza sativa), little is known about the molecular mechanisms underlying the observed reduction in seed size and yield. To elucidate the mechanistic basis of heat sensitivity and reduced seed size, we imposed a moderate (34°C) and a high (42°C) heat stress treatment on developing rice seeds during the postfertilization stage. Both stress treatments reduced the final seed size. At a cellular level, the moderate heat stress resulted in precocious endosperm cellularization, whereas severe heat-stressed seeds failed to cellularize. Initiation of endosperm cellularization is a critical developmental transition required for normal seed development, and it is controlled by Polycomb Repressive Complex2 (PRC2) in Arabidopsis (Arabidopsis thaliana). We observed that a member of PRC2 called Fertilization-Independent Endosperm1 (OsFIE1) was sensitive to temperature changes, and its expression was negatively correlated with the duration of the syncytial stage during heat stress. Seeds from plants overexpressing OsFIE1 had reduced seed size and exhibited precocious cellularization. The DNA methylation status and a repressive histone modification of OsFIE1 were observed to be temperature sensitive. Our data suggested that the thermal sensitivity of seed enlargement could partly be caused by altered epigenetic regulation of endosperm development during the transition from the syncytial to the cellularized state. PMID:24590858

Natural convection immersion cooling of an array of vertically oriented heated protrusions in an enclosure filled with a dielectric liquid: Effects of enclosure width, Prandtl number and component orientation

NASA Astrophysics Data System (ADS)

Matthews, Scott T.

1991-12-01

The natural convection heat transfer characteristics of a 3 x 3 array of vertically oriented heated protrusions, immersed in a dielectric liquid, were investigated. Aluminum blocks, 24 x 8 x 6 mm, were used to simulate 20 pin dual in-line packages. Surface temperature measurements of the components were made by imbedding copper-constantan thermocouples below the surface of each component face. A constant heat flux was provided to each component using an Inconel foil heating element. Power supplied to each component varied from 0.115 to 2.90 W. The aluminum blocks were mounted on a plexiglass substrate to form a 3 x 3 array of simulated electronic components. The circuit board containing the components was placed in a rectangular, plexiglass enclosure with inner dimensions: L = 203.2 mm H = 152.0 mm W = 82.6 mm, and a wall thickness of 25.4 mm. The upper boundary was maintained at 10 C, while all other exterior surfaces were insulated. The chamber width, measured from the surface of the circuit board to the opposite, inner wall of the enclosure, was varied from 42 to 7 mm by inserting plexiglass spacers into the enclosure. Two dielectric liquids, FC-75 and FC-43, were used as working fluids. Nondimensional data from this study was combined with the data obtained for a horizontal component orientation, to develop an empirical correlation which predicts the Nusselt number as a function of Rayleigh number, Prandtl number, component orientation, and chamber width.

A comparative analysis of loop heat pipe based thermal architectures for spacecraft thermal control

NASA Technical Reports Server (NTRS)

Pauken, Mike; Birur, Gaj

2004-01-01

Loop Heat Pipes (LHP) have gained acceptance as a viable means of heat transport in many spacecraft in recent years. However, applications using LHP technology tend to only remove waste heat from a single component to an external radiator. Removing heat from multiple components has been done by using multiple LHPs. This paper discusses the development and implementation of a Loop Heat Pipe based thermal architecture for spacecraft. In this architecture, a Loop Heat Pipe with multiple evaporators and condensers is described in which heat load sharing and thermal control of multiple components can be achieved. A key element in using a LHP thermal architecture is defining the need for such an architecture early in the spacecraft design process. This paper describes an example in which a LHP based thermal architecture can be used and how such a system can have advantages in weight, cost and reliability over other kinds of distributed thermal control systems. The example used in this paper focuses on a Mars Rover Thermal Architecture. However, the principles described here are applicable to Earth orbiting spacecraft as well.

Sensitivity study of the monogroove with screen heat pipe design

NASA Technical Reports Server (NTRS)

Evans, Austin L.; Joyce, Martin

1988-01-01

The present sensitivity study of design variable effects on the performance of a monogroove-with-screen heat pipe obtains performance curves for maximum heat-transfer rates vs. operating temperatures by means of a computer code; performance projections for both 1-g and zero-g conditions are obtainable. The variables in question were liquid and vapor channel design, wall groove design, and the number of feed lines in the evaporator and condenser. The effect on performance of three different working fluids, namely ammonia, methanol, and water, were also determined. Greatest sensitivity was to changes in liquid and vapor channel diameters.

78 FR 6251 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-30

... airplanes. This proposed AD was prompted by reports of cracks and heat damage on pivot joint components... proposing this AD to detect and correct heat damage and cracks in the pivot pin, truck beam lugs, and inner... joint components have been found with cracks or heat damage. There have been 11 such findings on Model...

Experiences on p-Version Time-Discontinuous Galerkin's Method for Nonlinear Heat Transfer Analysis and Sensitivity Analysis

NASA Technical Reports Server (NTRS)

Hou, Gene

2004-01-01

The focus of this research is on the development of analysis and sensitivity analysis equations for nonlinear, transient heat transfer problems modeled by p-version, time discontinuous finite element approximation. The resulting matrix equation of the state equation is simply in the form ofA(x)x = c, representing a single step, time marching scheme. The Newton-Raphson's method is used to solve the nonlinear equation. Examples are first provided to demonstrate the accuracy characteristics of the resultant finite element approximation. A direct differentiation approach is then used to compute the thermal sensitivities of a nonlinear heat transfer problem. The report shows that only minimal coding effort is required to enhance the analysis code with the sensitivity analysis capability.

Effect of heat and enzymatic treatments on human IgE and rabbit IgG sensitivity to white bean allergens.

PubMed

Bousfiha, Amal; Lotfi, Aarab

2013-08-28

The aim of this study was to evaluate the sensitivity of the population of Fez and Casablanca in Morocco to dry white beans (Phaseolus Vulgaris) and to investigate the effect of food processing (heat and/or enzymatic hydrolysis by pepsin) on this sensitivity. Work was based on a bank consisting of 146 sera from patients with atopic hypersensitivity in order to evaluate specific immunoglobulin E (IgE) levels to native and processed white bean proteins by ELISA. Under the same conditions, we assessed the immunoreactivity of rabbit IgG obtained by immunization with native white bean proteins.Evaluation of specific IgE to the white bean proteins showed that 51% of children and 39% of adults had positive values. The heat treatment and pepsin hydrolysis of dry bean proteins showed a reduction of 68% of IgE binding recognition in more than 65% of all patients. After heating, all patients indicated a reduction greater than 36%. With rabbit IgG, we observed a decrease by 25% of binding under heat treatment while enzymatic digestion reduced IgG recognition by 46.6%.These findings suggest that epitopes recognized by IgE in the studied population were conformational sites whereas those recognized by rabbit IgG were probably sequential. In conclusion, these results demonstrate that the Moroccan population was very sensitive to white beans and this sensitivity could be reduced after heat treatment or enzymatic hydrolysis.

The Sensitivity of the Midlatitude Moist Isentropic Circulation on Both Sides of the Climate Model Hierarchy

NASA Astrophysics Data System (ADS)

Fajber, R. A.; Kushner, P. J.; Laliberte, F. B.

2017-12-01

In the midlatitude atmosphere, baroclinic eddies are able to raise warm, moist air from the surface into the midtroposphere where it condenses and warms the atmosphere through latent heating. This coupling between dynamics and moist thermodynamics motivates using a conserved moist thermodynamic variable, such as the equivalent potential temperature, to study the midlatitude circulation and associated heat transport since it implicitly accounts for latent heating. When the equivalent potential temperature is used to zonally average the circulation, the moist isentropic circulation takes the form of a single cell in each hemisphere. By utilising the statistical transformed Eulerian mean (STEM) circulation we are able to parametrize the moist isentropic circulation in terms of second order dynamic and moist thermodynamic statistics. The functional dependence of the STEM allows us to analytically calculate functional derivatives that reveal the spatially varying sensitivity of the moist isentropic circulation to perturbations in different statistics. Using the STEM functional derivatives as sensitivity kernels we interpret changes in the moist isentropic circulation from two experiments: surface heating in an idealised moist model, and a climate change scenario in a comprehensive atmospheric general circulation model. In both cases we find that the changes in the moist isentropic circulation are well predicted by the functional sensitivities, and that the total heat transport is more sensitive to changes in dynamical processes driving local changes in poleward heat transport than it is to thermodynamic and/or radiative processes driving changes to the distribution of equivalent potential temperature.

Biophysical markers of the peripheral vasoconstriction response to pain in sickle cell disease

PubMed Central

Khaleel, Maha; Sunwoo, John; Shah, Payal; Detterich, Jon A.; Kato, Roberta M.; Thuptimdang, Wanwara; Meiselman, Herbert J.; Sposto, Richard; Tsao, Jennie; Wood, John C.; Zeltzer, Lonnie; Coates, Thomas D.; Khoo, Michael C. K.

2017-01-01

Painful vaso-occlusive crisis (VOC), a complication of sickle cell disease (SCD), occurs when sickled red blood cells obstruct flow in the microvasculature. We postulated that exaggerated sympathetically mediated vasoconstriction, endothelial dysfunction and the synergistic interaction between these two factors act together to reduce microvascular flow, promoting regional vaso-occlusions, setting the stage for VOC. We previously found that SCD subjects had stronger vasoconstriction response to pulses of heat-induced pain compared to controls but the relative degrees to which autonomic dysregulation, peripheral vascular dysfunction and their interaction are present in SCD remain unknown. In the present study, we employed a mathematical model to decompose the total vasoconstriction response to pain into: 1) the neurogenic component, 2) the vascular response to blood pressure, 3) respiratory coupling and 4) neurogenic-vascular interaction. The model allowed us to quantify the contribution of each component to the total vasoconstriction response. The most salient features of the components were extracted to represent biophysical markers of autonomic and vascular impairment in SCD and controls. These markers provide a means of phenotyping severity of disease in sickle-cell anemia that is based more on underlying physiology than on genotype. The marker of the vascular component (BMv) showed stronger contribution to vasoconstriction in SCD than controls (p = 0.0409), suggesting a dominant myogenic response in the SCD subjects as a consequence of endothelial dysfunction. The marker of neurogenic-vascular interaction (BMn-v) revealed that the interaction reinforced vasoconstriction in SCD but produced vasodilatory response in controls (p = 0.0167). This marked difference in BMn-v suggests that it is the most sensitive marker for quantifying combined alterations in autonomic and vascular function in SCD in response to heat-induced pain. PMID:28542469

Investigation of heat transfer of tube line of staggered tube bank in two-phase flow

NASA Astrophysics Data System (ADS)

Jakubcionis, Mindaugas

2015-06-01

This article presents the results of experimental investigation of heat transfer process, carried out using the model of heat exchanger. Two-phase statically stable foam flow was used as a heat transfer fluid. Heat exchanger model consisted of staggered tube bank. Experimental results are presented with the focus on influence of tube position in the line of the bank, volumetric void component and velocity of gas component of the foam. The phenomena of liquid draining in cellular foam flow and its influence on heat transfer rate has also been discussed. The experimental results have been generalized by relationship between Nusselt, Reynolds and Prandtl numbers.

Effect of microwave heating on the quality characteristics of canola oil in presence of palm olein.

PubMed

Ali, M Abbas; Nouruddeen, Zahrau Bamalli; Muhamad, Ida Idayu; Latip, Razam Abd; Othman, Noor Hidayu

2013-01-01

Microwave heating is one of the most attractive cooking methods for food preparation, commonly employed in households and especially in restaurants for its high speed and convenience. The chemical constituents of oils that degrade during microwave heating do so at rates that vary with heating temperature and time in a similar manner to other type of processing methods. The rate of quality characteristics of the oil depends on the fatty acid composition and the minor components during heating. Addition of oxidative-stable palm olein (PO) to heat sensitive canola oil (CO), may affect the quality characteristics of CO during microwave heating. The aim of this study was to evaluate how heat treatments by microwave oven affect the quality of CO in presence of PO. The blend was prepared in the volume ratio of 40:60 (PO:CO, PC). Microwave heating test was performed for different periods (2, 4, 8, 12, 16 and 20 min) at medium power setting for the samples of CO and PC. The changes in quality characteristics of the samples during heating were determined by analytical and instrumental methods. In this study, refractive index, free fatty acid content, peroxide value, p-anisidine value, TOTOX value, specific extinction, viscosity, polymer content, polar compounds and food oil sensor value of the oils all increased, whereas iodine value and C₁₈.₂ /C₁₆:₀ ratio decreased as microwave heating progressed. Based on the most oxidative stability criteria, PO addition led to a slower deterioration of CO at heating temperatures. The effect of microwave heating on the fatty acid composition of the samples was not remarkable. PO addition decelerated the formation of primary and secondary oxidation products in CO. However, effect of adding PO to CO on the formation of free fatty acids and polymers during microwave treatment was not significant (P < 0.05). No significant difference in food oil sensor value was detected between CO and PC throughout the heating periods. Microwave heating caused formation of comparatively lower amounts of some degradative products in PC compared to CO indicating a lower extent of oxidative degradation of PC.

Micro-satellites thermal control—concepts and components

NASA Astrophysics Data System (ADS)

Baturkin, Volodymyr

2005-01-01

The main idea of this paper is to present the survey of current tendencies in micro-satellites thermal control concepts that can be rational and useful for posterior missions due to intensive expansion of satellites of such type. For this purpose, the available references and lessons learned by the National Technical University of Ukraine during the elaboration of thermal control hardware for micro-satellites Magion 4, 5, BIRD and autonomous thermal control systems for interplanetary missions VEGA, PHOBOS have been used. The main parameters taken into consideration for analysis are the satellite sizes, mass, power consumption, orbit parameters, altitude control peculiarities and thermal control description. It was defined that passive thermal control concepts are widely used, excepting autonomous temperature regulation for sensitive components such as batteries, high-precision optics, and some types of sensors. The practical means for realization of passive thermal control design as multi-layer insulation, optical coatings, heat conductive elements, gaskets are briefly described.

A role for ocean biota in tropical intraseasonal atmospheric variability

NASA Astrophysics Data System (ADS)

Gildor, Hezi; Sobel, Adam H.; Cane, Mark A.; Sambrotto, Raymond N.

2003-05-01

We propose that temporal variations within the marine plankton system can induce intraseasonal variations in sea surface temperature (SST) through the effect on solar penetration due to chlorophyll and other optically active organic components. Sensitivity studies with a simple model suggest that these small oscillations in SST may stimulate radiative-convective oscillations in the atmosphere which amplify them and thus induce or modulate significant variability in the coupled system. Long term bio-optical measurements in the Western Pacific, where satellite time series are degraded by clouds, would provide a test of our theory and would improve our understanding of the heat balance in this climatically important region.

Sensitivity of porcine epidemic diarrhea virus (PEDV) to pH and heat treatment in the presence or absence of porcine plasma.

PubMed

Quist-Rybachuk, G V; Nauwynck, H J; Kalmar, I D

2015-12-31

Emergence of porcine epidemic diarrhea virus (PEDV) resulted in massive neonatal mortality in the North-American and Asian pork industry. Measures to prevent its geographical spread are of utmost importance to safeguard susceptible porcine populations. The major infection route is direct or indirect faecal-oral contact. Adequate biosafety measures should be in place at all levels of the swine production chain, including feed and feed ingredients. Present study aimed to investigate the sensitivity of PEDV to thermal inactivation at neutral and alkaline pH in presence or absence of porcine plasma. Cell culture medium and porcine plasma at different pH (7.2, 9.2, 10.2) and temperature conditions (4 °C, 40 °C, 44 °C, 48 °C) were inoculated to a final titer of 5.5 log10 TCID50 PEDV/ml, incubated for up to 120 min and the residual infectivity was determined by endpoint dilution assay. Irrespective of presence of plasma, PEDV was not sensitive to pH 7.2-10.2 at 4 °C. At moderate temperatures (≥40 °C), both alkaline pH and presence of plasma potentiated thermal inactivation. Inactivation of 8 log10 TCID50/ml plasma within 30 min (8D value<30 min) by moderate pH and temperature would denote potential industrial processing conditions that ensure safety towards PEDV while limiting denaturation of bioactive components. Virus-spiked plasma required heat treatment of 40 °C and alkalinization to pH 9.2 to achieve 8 log10 reduction within such time. At pH 10.2 and 48 °C, the 8D value was 4.6 min in plasma and 15.2 min in MEM. Here we propose heat-alkalinity-time (HAT) pasteurization as a highly efficient method to inactivate PEDV during industrial processing of porcine plasma. Copyright © 2015 Elsevier B.V. All rights reserved.

Plasma-Facing Component and Materials Testing for the NSTX-U

NASA Astrophysics Data System (ADS)

Jaworski, Michael; Brooks, A.; Gerhardt, S.; Loesser, D.; Mardenfeld, M.; Menard, J.; Gray, T.; Reinke, M.

2017-10-01

The NSTX-U Recovery Project is developing plasma-facing components for use in the divertor of NSTX-U. The extreme conditions of the NSTX-U divertor make it possible to stress even graphite surfaces to the material limits leading to the possibility of component failures. In addition, the complex, mixed-material environment of the NSTX-U due to the use of boron and lithium wall conditioning techniques creates significant uncertainties in the monitoring of the PFCs. A testing program has been developed to inform on the material and design limitations of the NSTX-U high-heat flux components. These tests include high-heat flux testing in electron beam facilities as well as plasma-based testing. The NSTX-U components could experience perpendicular heat fluxes as high as 45 MW/m2. Parallel heat fluxes onto leading edges could reach 475 MW/m2. The testing program and material survey plan will be presented. Work supported by DOE contract DE-AC02-09CH11466 and DE-AC05-00OR22725.

Thermal Degradation and Identification of Heat-Sensitive Polymers

ERIC Educational Resources Information Center

Clough, Stuart C.; Goldman, Emma W.

2005-01-01

A study demonstrates the thermal degradation of two heat-sensitive polymers, namely, polystyrene and poly (methyl methacrylate). The experiment described in the study introduces undergraduate students to polymer structure as well as the application of spectroscopic techniques to the solution of structural problems.

GALLIUM CITRATE, A NEW SENSITIZER OF CELLS TO HYPERTHERMIA

PubMed Central

Shinohara, Kunio; Kawakami, Noriko; Kugotani, Maho; Nakano, Hisako

1988-01-01

The killing effects of heat were studied on cultured mammalian cells (L5178Y) pre‐incubated with gallium (Ga) citrate, which is a popular tumor‐imaging diagnostic agent. The cells showed higher sensitivity to heat when they were pre‐incubated with Ga‐citrate. The pre‐incubated cells showed decreased ATP levels, and this may be responsible for the heat‐sensitizing effect. PMID:3128502

Materials Development for Auxiliary Components for Large Compact Mo/Au TES Arrays

NASA Technical Reports Server (NTRS)

Finkbeiner, F. m.; Chervenak, J. A.; Bandler, S. R.; Brekosky, R.; Brown, A. D.; Figueroa-Feliciano, E.; Iyomoto, N.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.;

Mutagenicity and clastogenicity of extracts of Helicobacter pylori detected by the Ames test and in the micronucleus test using human lymphoblastoid cells.

PubMed

Arimoto-Kobayashi, Sakae; Ohta, Kaori; Yuhara, Yuta; Ayabe, Yuka; Negishi, Tomoe; Okamoto, Keinosuke; Nakajima, Yoshihiro; Ishikawa, Takeshi; Oguma, Keiji; Otsuka, Takanao

2015-07-01

Epidemiological studies have demonstrated a close association between infection with Helicobacter pylori (H.pylori) and the development of gastric carcinoma. Chronic H.pylori infection increases the frequency of mutation in gastric epithelial cells. However, the mechanism by which infection of H.pylori leads to mutation in gastric epithelial cells is unclear. We suspected that components in H.pylori may be related to the mutagenic response associated with DNA alkylation, and could be detected with the Ames test using a more sensitive strain for alkylating agents. Our investigation revealed that an extract of H.pylori was mutagenic in the Ames test with Salmonella typhimurium YG7108, which is deficient in the DNA repair of O(6)-methylguanine. The extract of H.pylori may contain methylating or alkylating agents, which might induce O (6)-alkylguanine in DNA. Mutagenicity of the alkylating agents N-methyl-N-nitrosourea (MNU) and N-methyl-N'-nitro-N-nitrosoguanidine in the Ames test with S.typhimurium TA1535 was enhanced significantly in the presence of the extract of H.pylori. The tested extracts of H.pylori resulted in a significant induction of micronuclei in human-derived lymphoblastoid cells. Heat instability and dialysis resistance of the extracts of H.pylori suggest that the mutagenic component in the extracts of H.pylori is a heat-unstable large molecule or a heat-labile small molecule strongly attached or adsorbed to a large molecule. Proteins in the extracts of H.pylori were subsequently fractionated using ammonium sulphate precipitation. However, all fractions expressed enhancing effects toward MNU mutagenicity. These results suggest the mutagenic component is a small molecule that is absorbed into proteins in the extract of H.pylori, which resist dialysis. Continuous and chronic exposure of gastric epithelial cells to the alkylative mutagenic component from H.pylori chronically infected in the stomach might be a causal factor in the gastric carcinogenesis associated with H.pylori. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Selected Heat-Sensitive Antibiotics Are Not Inactivated During Polymethylmethacrylate Curing and Can Be Used in Cement Spacers for Periprosthetic Joint Infection.

PubMed

Carli, Alberto V; Sethuraman, Arvinth S; Bhimani, Samrath J; Ross, Frederick P; Bostrom, Mathias P G

2018-06-01

Antibiotic use in polymethylmethacrylate (PMMA) spacers has historically been limited to those which are "heat-stable" and thus retain their antimicrobial properties after exposure to the high temperatures which occur during PMMA curing. This study examines the requirement of "heat stability" by measuring temperatures of Palacos and Simplex PMMA as they cure inside commercial silicone molds of the distal femur and proximal tibia. Temperature probes attached to thermocouples were placed at various depths inside the molds and temperatures were recorded for 20 minutes after PMMA introduced and a temperature curve for each PMMA product was determined. A "heat-stable" antibiotic, vancomycin, and a "heat-sensitive" antibiotic, ceftazidime, were placed in a programmable thermocycler and exposed to the same profile of PMMA curing temperatures. Antimicrobial activity against Staphylococcus aureus was compared for heat-treated antibiotics vs room temperature controls. Peak PMMA temperatures were significantly higher in tibial (115.2°C) vs femoral (85.1°C; P < .001) spacers. In the hottest spacers, temperatures exceeded 100°C for 3 minutes. Simplex PMMA produced significantly higher temperatures (P < .05) compared with Palacos. Vancomycin bioactivity did not change against S aureus with heat exposure. Ceftazidime bioactivity did not change when exposed to femoral temperature profiles and was reduced only 2-fold with tibial profiles. The curing temperatures of PMMA in knee spacers are not high enough or maintained long enough to significantly affect the antimicrobial efficacy of ceftazidime, a known "heat-sensitive" antibiotic. Future studies should investigate if more "heat-sensitive" antibiotics could be used clinically in PMMA spacers. Copyright © 2018 Elsevier Inc. All rights reserved.

Enhanced heat transport in environmental systems using microencapsulated phase change materials

NASA Technical Reports Server (NTRS)

Colvin, D. P.; Mulligan, J. C.; Bryant, Y. G.

1992-01-01

A methodology for enhanced heat transport and storage that uses a new two-component fluid mixture consisting of a microencapsulated phase change material (microPCM) for enhanced latent heat transport is outlined. SBIR investigations for NASA, USAF, SDIO, and NSF since 1983 have demonstrated the ability of the two-component microPCM coolants to provide enhancements in heat transport up to 40 times over that of the carrier fluid alone, enhancements of 50 to 100 percent in the heat transfer coefficient, practically isothermal operation when the coolant flow is circulated in an optimal manner, and significant reductions in pump work.

Toughness of 2,25Cr-1Mo steel and weld metal

NASA Astrophysics Data System (ADS)

Acarer, Mustafa; Arici, Gökhan; Acar, Filiz Kumdali; Keskinkilic, Selcuk; Kabakci, Fikret

2017-09-01

2,25Cr-1Mo steel is extensively used at elevated temperature structural applications in fossil fire power plants for steam pipes, nozzle chambers and petrochemical industry for hydrocracking unit due to its excellent creep resistance and good redundant to oxidation. Also they should have acceptable weldability and toughness. The steels are supplied in quenched and tempered condition and their welded components are subjected to post-weld heat treatment (PWHT). Tempering process is carried out at 690-710°C to improve toughness properties. However they are sensitive to reheat cracking and temper embrittlement. To measure temper embrittlement of the steels and their weld metal, temper embrittlement factor and formula (J factor - Watanabe and X formula- Bruscato) are used. Step cooling heat treatment is also applied to determine temper embrittlement. In this study, toughness properties of Cr Mo (W) steels were reviewed. Also transition temperature curves of 2,25Cr-1Mo steel and its weld metal were constructed before and after step cool heat treatment as experimental study. While 2,25Cr-1Mo steel as base metal was supplied, all weld metal samples were produced in Gedik Welding Company. Hardness measurements and microstructure evaluation were also carried out.

The advantages of wearable green reflected photoplethysmography.

PubMed

Maeda, Yuka; Sekine, Masaki; Tamura, Toshiyo

2011-10-01

This report evaluates the efficacy of reflected-type green light photoplethysmography (green light PPG). Transmitted infrared light was used for PPG and the arterial pulse was monitored transcutaneously. The reflected PPG signal contains AC components based on the heartbeat-related signal from the arterial blood flow and DC components, which include reflectance and scattering from tissue. Generally, changes in AC components are monitored, but the DC components play an important role during heat stress. In this study, we compared the signal of green light PPG to infrared PPG and ECG during heat stress. The wavelengths of the green and infrared light were 525 nm and 880 nm, respectively. Experiments were performed on young healthy subjects in cold (10°C), hot (45°C), and normal environments. The pulse rates were compared among three measurement devices and the AC and DC components of the PPG signal were evaluated during heat stress. The pulse rates obtained from green light PPG were strongly correlated with the R-R interval of an electrocardiogram in all environments, but those obtained from infrared light PPG displayed a weaker correlation with cold exposure. The AC components were of similar signal output for both wavelengths during heat stress. Also, the DC components for green light PPG were similar during heat stress, but showed less signal output for infrared light PPG during hot exposure. The main reason for the reduced DC components was speculated to be the increased blood flow at the vascular bed. Therefore, reflected green light PPG can be useful for pulse rate monitoring because it is less influenced by the tissue and vein region.

Pain hypervigilance is associated with greater clinical pain severity and enhanced experimental pain sensitivity among adults with symptomatic knee osteoarthritis

PubMed Central

Herbert, Matthew S.; Goodin, Burel R.; Pero, Samuel T.; Schmidt, Jessica K.; Sotolongo, Adriana; Bulls, Hailey W.; Glover, Toni L.; King, Christopher D.; Sibille, Kimberly T.; Cruz-Almeida, Yenisel; Staud, Roland; Fessler, Barri J.; Bradley, Laurence A.; Fillingim, Roger B.

2014-01-01

Background Pain hypervigilance is an important aspect of the fear-avoidance model of pain that may help explain individual differences in pain sensitivity among persons with knee osteoarthritis (OA). Purpose The purpose of this study was to examine the contribution of pain hypervigilance to clinical pain severity and experimental pain sensitivity in persons with symptomatic knee OA. Methods We analyzed cross-sectional data from 168 adults with symptomatic knee OA. Quantitative sensory testing was used to measure sensitivity to heat pain, pressure pain, and cold pain, as well as temporal summation of heat pain, a marker of central sensitization. Results Pain hypervigilance was associated with greater clinical pain severity, as well as greater pressure pain. Pain hypervigilance was also a significant predictor of temporal summation of heat pain. Conclusions Pain hypervigilance may be an important contributor to pain reports and experimental pain sensitivity among persons with knee OA. PMID:24352850

The role of atmospheric internal variability on the prediction skill of interannual North Pacific sea-surface temperatures

NASA Astrophysics Data System (ADS)

Narapusetty, Balachandrudu

2017-06-01

The sensitivity of the sea-surface temperature (SST) prediction skill to the atmospheric internal variability (weather noise) in the North Pacific (20∘-60∘N;120∘E-80∘W) on decadal timescales is examined using state-of-the-art Climate Forecasting System model version 2 (CFS) and a variation of CFS in an Interactive Ensemble approach (CFSIE), wherein six copies of atmospheric components with different perturbed initial states of CFS are coupled with the same ocean model by exchanging heat, momentum and fresh water fluxes dynamically at the air-sea interface throughout the model integrations. The CFSIE experiments are designed to reduce weather noise and using a few ten-year long forecasts this study shows that reduction in weather noise leads to lower SST forecast skill. To understand the pathways that cause the reduced SST prediction skill, two twenty-year long forecasts produced with CFS and CFSIE for 1980-2000 are analyzed for the ocean subsurface characteristics that influence SST due to the reduction in weather noise in the North Pacific. The heat budget analysis in the oceanic mixed layer across the North Pacific reveals that weather noise significantly impacts the heat transport in the oceanic mixed layer. In the CFSIE forecasts, the reduced weather noise leads to increased variations in heat content due to shallower mixed layer, diminished heat storage and enhanced horizontal heat advection. The enhancement of the heat advection spans from the active Kuroshio regions of the east coast of Japan to the west coast of continental United States and significantly diffuses the basin-wide SST anomaly (SSTA) contrasts and leads to reduction in the SST prediction skill in decadal forecasts.

Design and testing of a liquid cooled garment for hot environments.

PubMed

Guo, Tinghui; Shang, Bofeng; Duan, Bin; Luo, Xiaobing

2015-01-01

Liquid cooled garments (LCGs) are considered a viable method to protect individuals from hyperthermia and heat-related illness when working in thermally stressful environments. While the concept of LCGs was proposed over 50 years ago, the design and testing of these systems is undeveloped and stands in need of further study. In this study, a detailed heat transfer model of LCG in a hot environment was built to analyze the effects of different factors on the LCG performance, and to identify the main limitations to achieve maximum performance. An LCG prototype was designed and fabricated. Series of tests were done by a modified thermal manikin method to validate the heat transfer model and to evaluate the thermal properties. Both experimental and predicted results show that the heat flux components match the heat balance equation with an error of less than 10% at different flowrate. Thermal resistance analysis also manifests that the thermal resistance between the cooling water and the ambient (R2) is more sensitive to the flowrate than to the one between the skin surface and the cooling water (R1). When the flowrate increased from 225 to 544 mL/min, R2 decreased from 0.5 to 0.3 °C m(2)/W while R1 almost remained constant. A specific duration time was proposed to assess the durability and an optimized value of 1.68 h/kg was found according to the heat transfer model. The present heat transfer model and specific duration time concept could be used to optimize and evaluate this kind of LCG respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Particle swarm optimization of the sensitivity of a cryogenic gravitational wave detector

NASA Astrophysics Data System (ADS)

Michimura, Yuta; Komori, Kentaro; Nishizawa, Atsushi; Takeda, Hiroki; Nagano, Koji; Enomoto, Yutaro; Hayama, Kazuhiro; Somiya, Kentaro; Ando, Masaki

2018-06-01

Cryogenic cooling of the test masses of interferometric gravitational wave detectors is a promising way to reduce thermal noise. However, cryogenic cooling limits the incident power to the test masses, which limits the freedom of shaping the quantum noise. Cryogenic cooling also requires short and thick suspension fibers to extract heat, which could result in the worsening of thermal noise. Therefore, careful tuning of multiple parameters is necessary in designing the sensitivity of cryogenic gravitational wave detectors. Here, we propose the use of particle swarm optimization to optimize the parameters of these detectors. We apply it for designing the sensitivity of the KAGRA detector, and show that binary neutron star inspiral range can be improved by 10%, just by retuning seven parameters of existing components. We also show that the sky localization of GW170817-like binaries can be further improved by a factor of 1.6 averaged across the sky. Our results show that particle swarm optimization is useful for designing future gravitational wave detectors with higher dimensionality in the parameter space.

An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

PubMed Central

Henrich, Florian; Magerl, Walter; May, Arne

2014-01-01

This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all p<0.001). Thus, repetitive heat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

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

PubMed

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-07-02

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

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

PubMed Central

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-01-01

We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications. PMID:28671600

The effect of processing on veterinary residues in foods.

PubMed

Moats, W A

1999-01-01

Heat stability of antibiotics in foods to cooking has been determined by a variety of methods. These include heating in such liquid media as milk, water, buffers and meat extracts, and in solids such as buffered meat homogenates and various sausages. Inactivation of incurred residues in tissues and eggs was also studied. Time and temperature of heating were more easily controlled in liquid media, but results in actual meat products are more indicative of actual cooking processes. Ordinary cooking procedures for meat, even to "well-done", cannot be relied on to inactivate even the more heat sensitive compounds such as penicillins and tetracyclines. More severe heating as for canning or prolonged cooking with moist heat can inactivate the more heat sensitive compounds. The relevance to food safety is uncertain since the nature of the degradation products is unknown in most cases.

Heated tool for autoclaves

NASA Technical Reports Server (NTRS)

Serafini, T. T.; Vanucci, R. D.; Cavano, P. J.; Winters, W. E.

1980-01-01

Components made of composite materials are heated in autoclaves by employing electrical resistance heating blankets, thus avoiding need to heat entire autoclave volume. Method provides not only significant energy savings compared to heating entire pressure vessel but offers time savings in accelerated heat-up and cool-down cycles.

Inexpensive economical solar heating system for homes (un sistema economico de calefaccion solar para viviendas)

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

Alfred, J.W.; Shinn, J.M. Jr; Kirby, C.E.

1976-07-01

This report describes a low-cost solar home heating system to supplement the home-owner's present warm-air heating system. It has three parts: (1) A brief background on solar heating, (2) Langley's experience with a demonstration system, and (3) information for the home-owner who wishes to construct such a system. Instructions are given for a solar heating installation in which he supplies all labor needed to install off-the-shelf components estimated to cost $2000. These components, which include solar collector, heat exchanger, water pump, storage tank, piping, and controls to make the system completely automatic, are readily available at local lumber yards, hardwaremore » stores, and plumbing supply stores, and they are relatively simple to install. Manufacturers and prices of each component used and a rough cost analysis based on these prices are given for the owner's convenience. This report also gives performance data obtained from a demonstration system which has been built and tested at the Langley Research Center.« less

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) located at Hampton, Virginia became operational in early summer of 1976. This facility is a joint effort by NASA-Lewis and NASA-Langley 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 performance of 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 given here, along with the objectives, test approach, expected system performance and some preliminary results.

Sensitivity of Latent Heating Profiles to Environmental Conditions: Implications for TRMM and Climate Research

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Einaudi, Franco (Technical Monitor)

2000-01-01

The Tropical Rainfall Measuring Mission (TRMM) as a part of NASA's Earth System Enterprise is the first mission dedicated to measuring tropical rainfall through microwave and visible sensors, and includes the first spaceborne rain radar. Tropical rainfall comprises two-thirds of global rainfall. It is also the primary distributor of heat through the atmosphere's circulation. It is this circulation that defines Earth's weather and climate. Understanding rainfall and its variability is crucial to understanding and predicting global climate change. Weather and climate models need an accurate assessment of the latent heating released as tropical rainfall occurs. Currently, cloud model-based algorithms are used to derive latent heating based on rainfall structure. Ultimately, these algorithms can be applied to actual data from TRMM. This study investigates key underlying assumptions used in developing the latent heating algorithms. For example, the standard algorithm is highly dependent on a system's rainfall amount and structure. It also depends on an a priori database of model-derived latent heating profiles based on the aforementioned rainfall characteristics. Unanswered questions remain concerning the sensitivity of latent heating profiles to environmental conditions (both thermodynamic and kinematic), regionality, and seasonality. This study investigates and quantifies such sensitivities and seeks to determine the optimal latent heating profile database based on the results. Ultimately, the study seeks to produce an optimized latent heating algorithm based not only on rainfall structure but also hydrometeor profiles.

[Are amylases in bakery products and flour potential food allergens?].

PubMed

Baur, X; Sander, I; Jansen, A; Czuppon, A B

1994-05-21

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

Sensitizing effects of gallium citrate on hyperthermic cell killing in vitro.

PubMed

Miyazaki, N; Nakano, H; Kawakami, N; Kugotani, M; Nishihara, K; Aoki, Y; Shinohara, K

2000-01-01

The lethal effects of gallium citrate in combination with heat were studied using four cell lines, L5178Y, FM3A, P388 and HeLa. Cells were incubated with different concentrations (0.2 2 mM) of gallium citrate at 37 degrees C for 24 h and heated at a range of temperatures from 40-44 degrees C for various time periods up to 6 h in the absence of gallium citrate. Survival and cell viability were determined by clonogenic assay and the dye-exclusion test, respectively. All of the cell lines tested were insensitive to heat below 41 degrees C, but were very sensitive to heat above 43 degrees C. Gallium citrate was cytotoxic to these cell lines at different levels: P388 and HeLa were far more sensitive than L5178Y and FM3A. The killing effects of heat at 41 degrees C were greatly enhanced by gallium citrate in L5178Y and P388 cells. The Arrhenius analysis for the lethal effect of heat, determined by clonogenic assay, in L5178Y cells showed that the transition temperature was remarkably decreased for the gallium-treated cells from approximately 43 degrees C to 41 degrees C. The mechanism for this decrease in the transition temperature may be attributable to the additional effects of gallium citrate on energy metabolism. Preincubation with 0.05 mM gallium citrate at 37 degrees C for 7 days also enhanced heat sensitization at 41 degrees C in L5178Y. This preincubation condition may correspond to the condition for the continuous infusion of gallium that is clinically used for cancer treatment. In contrast, treatment with gallium did not greatly enhance the sensitivity of FM3A or HeLa cells to heat at 41 degrees C, but the effects of gallium were significant.

Thermal sprayed composite melt containment tubular component and method of making same

DOEpatents

Besser, Matthew F.; Terpstra, Robert L.; Sordelet, Daniel J.; Anderson, Iver E.

2002-03-19

A tubular thermal sprayed melt containment component for transient containment of molten metal or alloy wherein the tubular member includes a thermal sprayed inner melt-contacting layer for contacting molten metal or alloy to be processed, a thermal sprayed heat-generating layer deposited on the inner layer, and an optional thermal sprayed outer thermal insulating layer. The thermal sprayed heat-generating layer is inductively heated as a susceptor of an induction field or electrical resistively heated by passing electrical current therethrough. The tubular thermal sprayed melt containment component can comprise an elongated melt pour tube of a gas atomization apparatus where the melt pour tube supplies molten material from a crucible to an underlying melt atomization nozzle.

High rate fabrication of compression molded components

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

Matsen, Marc R.; Negley, Mark A.; Dykstra, William C.

2016-04-19

A method for fabricating a thermoplastic composite component comprises inductively heating a thermoplastic pre-form with a first induction coil by inducing current to flow in susceptor wires disposed throughout the pre-form, inductively heating smart susceptors in a molding tool to a leveling temperature with a second induction coil by applying a high-strength magnetic field having a magnetic flux that passes through surfaces of the smart susceptors, shaping the magnetic flux that passes through surfaces of the smart susceptors to flow substantially parallel to a molding surface of the smart susceptors, placing the heated pre-form between the heated smart susceptors; andmore » applying molding pressure to the pre-form to form the composite component.« less

Laser heating and detection of bilayer microcantilevers for non-contact thermodynamic measurements

NASA Astrophysics Data System (ADS)

Burke, Brian G.; LaVan, David A.

2013-01-01

We describe a method for optical detection (frequency and position) and heating of bilayer microcantilevers (BMCs) to high temperatures at fast heating rates (106°C/s to 109°C/s) for non-contact thermodynamic measurements of small quantities of materials in the femtogram range. The current experimental apparatus with a 2 μm × 10 μm BMC achieves a deflection sensitivity of 0.1 Å, heating rate of 3.0 × 106°C/s, and heat sensitivity of 18 pJ in a 3 kHz bandwidth in air. By measuring the resonant frequency shift after sample loading, we achieve a mass resolution of 2.67 fg.

Laser Assisted Micro Wire GMAW and Droplet Welding

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

FUERSCHBACH, PHILLIP W.; LUCK, D. L.; BERTRAM, LEE A.

2002-03-01

Laser beam welding is the principal welding process for the joining of Sandia weapon components because it can provide a small fusion zone with low overall heating. Improved process robustness is desired since laser energy absorption is extremely sensitive to joint variation and filler metal is seldom added. This project investigated the experimental and theoretical advantages of combining a fiber optic delivered Nd:YAG laser with a miniaturized GMAW system. Consistent gas metal arc droplet transfer employing a 0.25 mm diameter wire was only obtained at high currents in the spray transfer mode. Excessive heating of the workpiece in this modemore » was considered an impractical result for most Sandia micro-welding applications. Several additional droplet detachment approaches were investigated and analyzed including pulsed tungsten arc transfer(droplet welding), servo accelerated transfer, servo dip transfer, and electromechanically braked transfer. Experimental observations and rigorous analysis of these approaches indicate that decoupling droplet detachment from the arc melting process is warranted and may someday be practical.« less

Exploring the hidden interior of the Earth with directional neutrino measurements

PubMed Central

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

2017-01-01

Roughly 40% of the Earth’s total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth’s radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth. PMID:28691700

Adaptation of an urban land surface model to a tropical suburban area: Offline evaluation, sensitivity analysis, and optimization of TEB/ISBA (SURFEX)

NASA Astrophysics Data System (ADS)

Harshan, Suraj

The main objective of the present thesis is the improvement of the TEB/ISBA (SURFEX) urban land surface model (ULSM) through comprehensive evaluation, sensitivity analysis, and optimization experiments using energy balance and radiative and air temperature data observed during 11 months at a tropical sub-urban site in Singapore. Overall the performance of the model is satisfactory, with a small underestimation of net radiation and an overestimation of sensible heat flux. Weaknesses in predicting the latent heat flux are apparent with smaller model values during daytime and the model also significantly underpredicts both the daytime peak and nighttime storage heat. Surface temperatures of all facets are generally overpredicted. Significant variation exists in the model behaviour between dry and wet seasons. The vegetation parametrization used in the model is inadequate to represent the moisture dynamics, producing unrealistically low latent heat fluxes during a particularly dry period. The comprehensive evaluation of the USLM shows the need for accurate estimation of input parameter values for present site. Since obtaining many of these parameters through empirical methods is not feasible, the present study employed a two step approach aimed at providing information about the most sensitive parameters and an optimized parameter set from model calibration. Two well established sensitivity analysis methods (global: Sobol and local: Morris) and a state-of-the-art multiobjective evolutionary algorithm (Borg) were employed for sensitivity analysis and parameter estimation. Experiments were carried out for three different weather periods. The analysis indicates that roof related parameters are the most important ones in controlling the behaviour of the sensible heat flux and net radiation flux, with roof and road albedo as the most influential parameters. Soil moisture initialization parameters are important in controlling the latent heat flux. The built (town) fraction has a significant influence on all fluxes considered. Comparison between the Sobol and Morris methods shows similar sensitivities, indicating the robustness of the present analysis and that the Morris method can be employed as a computationally cheaper alternative of Sobol's method. Optimization as well as the sensitivity experiments for the three periods (dry, wet and mixed), show a noticeable difference in parameter sensitivity and parameter convergence, indicating inadequacies in model formulation. Existence of a significant proportion of less sensitive parameters might be indicating an over-parametrized model. Borg MOEA showed great promise in optimizing the input parameters set. The optimized model modified using the site specific values for thermal roughness length parametrization shows an improvement in the performances of outgoing longwave radiation flux, overall surface temperature, heat storage flux and sensible heat flux.

Development of micro-heaters with optimized temperature compensation design for gas sensors.

PubMed

Hwang, Woo-Jin; Shin, Kyu-Sik; Roh, Ji-Hyoung; Lee, Dae-Sung; Choa, Sung-Hoon

2011-01-01

One of the key components of a chemical gas sensor is a MEMS micro-heater. Micro-heaters are used in both semiconductor gas sensors and NDIR gas sensors; however they each require different heat dissipation characteristics. For the semiconductor gas sensors, a uniform temperature is required over a wide area of the heater. On the other hand, for the NDIR gas sensor, the micro-heater needs high levels of infrared radiation in order to increase sensitivity. In this study, a novel design of a poly-Si micro-heater is proposed to improve the uniformity of heat dissipation on the heating plate. Temperature uniformity of the micro-heater is achieved by compensating for the variation in power consumption around the perimeter of the heater. With the power compensated design, the uniform heating area is increased by 2.5 times and the average temperature goes up by 40 °C. Therefore, this power compensated micro-heater design is suitable for a semiconductor gas sensor. Meanwhile, the poly-Si micro-heater without compensation shows a higher level of infrared radiation under equal power consumption conditions. This indicates that the micro-heater without compensation is more suitable for a NDIR gas sensor. Furthermore, the micro-heater shows a short response time of less than 20 ms, indicating a very high efficiency of pulse driving.

Differential temperature preferences and thresholds among summer campers in Ontario's southern provincial parks: a Canadian case study in tourism climatology

NASA Astrophysics Data System (ADS)

Hewer, Micah J.; Scott, Daniel J.; Gough, William A.

2017-08-01

Weather and climate are important factors in relation to outdoor recreation and tourism. Camping and park visitation are weather sensitive activities very likely to be impacted by projected climate change. Temperature is the weather variable that has received the greatest attention within the tourism climatology literature and was the greatest predictor of park visitation within previous assessments. This study uses a stated climate preferences approach, relying on survey-based data, to explore differences for temperature preferences and thresholds among campers in Ontario parks. Statistically significant differences (at the 95% confidence level) in mean values for temperature preferences and thresholds were recorded based on various camper characteristics, such as the following: activity selection, age, gender, distance travelled, length of stay, life cycle stage, camping experience, and camping equipment. Swimmers preferred warmer day-time temperatures. Older campers preferred cooler temperatures and were more sensitive to heat stress, in the day and night time. Females preferred warmer temperatures and were less sensitive to heat stress during the night time. Campers who had travelled further distances to reach the park or planned to stay for longer periods were less sensitive to heat stress. Campers with children in their group preferred warmer temperatures and were less sensitive to heat stress, in the day and at night. Respondents with higher levels of camping experience preferred warmer temperatures at night. Tent campers were less sensitive to heat stress, in the day and at night. The results of this study have direct implications for previous and future climate change impact assessments on park visitation.

Determining predictability and accuracy of thermal and electrical dental pulp tests: An in vivo study.

PubMed

Salgar, Avinash Ramchandra; Singh, Shishir H; Podar, Rajesh S; Kulkarni, Gaurav P; Babel, Shashank N

2017-01-01

Pulp sensitivity testing, even with its limitations and shortcomings, has been and still remains a very helpful aid in endodontic diagnosis. Pulp sensitivity tests extrapolate pulpal health from the sensory response. The aim of the present study was to identify the sensitivity, specificity, positive and negative predictive values (NPVs) of thermal and electrical tests of pulp sensitivity. Pulp tests studied were two cold and heat tests respectively and electrical test. A total of 330 teeth were tested: 198 teeth with vital pulp and 132 teeth with necrotic pulps (disease prevalence of 40%). The ideal standard was established by observing bleeding within the pulp chamber. Sensitivity values of the diagnostic tests were 0.89 and 0.94 for cold test, 0.84 and 0.87 for the heat tests, and 0.75 for electrical pulp test and the specificity values of the diagnostic tests were 0.91 and 0.93 for the cold tests, 0.86 and 0.84 for the heat tests, and 0.90 for electrical pulp test. The NPVs were 0.91 and 0.96 for the cold tests, 0.89 and 0.91 for the heat tests, and 0.84 for electrical pulp test. The positive predictive values were 0.89 and 0.90 for the cold tests, 0.80 and 0.79 for the heat tests and 0.88 for electrical pulp test. The highest accuracy (0.9393) was observed with cold test (icy spray). The cold test done with icy spray was the most accurate method for sensitivity testing.

Heat flux-based strategies for the thermal monitoring of sub-fumarolic areas: Examples from Vulcano and La Soufrière de Guadeloupe

NASA Astrophysics Data System (ADS)

Gaudin, Damien; Ricci, Tullio; Finizola, Anthony; Delcher, Eric; Alparone, Salvatore; Barde-Cabusson, Stéphanie; Brothelande, Elodie; Di Gangi, Fabio; Gambino, Salvatore; Inguaggiato, Salvatore; Milluzzo, Vincenzo; Peltier, Aline; Vita, Fabio

2017-09-01

Although it is relatively easy to set-up, the monitoring of soil temperature in sub-fumarolic areas is quite rarely used to monitor the evolution of hydrothermal systems. Indeed, measurements are highly sensitive to environmental conditions, in particular daily and seasonal variations of atmospheric temperatures and rainfalls, which can be only partially filtered by the established statistical analysis. In this paper, we develop two innovative processing methods, both based on the computation of the heat flux in the soil. The upward heat flux method (UHF), designed for dry environments, consists in computing both the conductive and convective components of the heat flux between two thermocouples placed vertically. In the cases of wet environments, the excess of total heat method (ETH) allows the integration of rain gauges data in order to correct the heat balance from the superficial cooling effect of the precipitations. The performances of both processing techniques are faced to established methods (temperature gradient and coefficient of determination) on soil temperature time series from two test volcanoes. At La Fossa di Vulcano (Italy), the UHF method undoubtedly detects three thermal crises between 2009 and 2012, enabling to quantify not only the intensity but also the precise timing of the heat flux increase with respect to corresponding geochemical and seismic crises. At La Soufrière de Guadeloupe (French Lesser Antilles), despite large rainfalls dramatically influencing the thermal behavior of the soil, a constant geothermal heat flux is retrieved by the ETH method, confirming the absence of fumarolic crisis during the observation period (February-August 2010). Being quantitative, robust, and usable in almost any context of sub-fumarolic zones, our two heat flux-based methods increase the potential of soil temperature for the monitoring, but also the general interpretation of fumarolic crises together with geochemical and seismological observations. A spreadsheet allowing direct computation of UHF and ETH is provided as supplemental material.

Heat-stressed structural components in combustion-engine design

NASA Technical Reports Server (NTRS)

Kraemer, Otto

1938-01-01

Heated structural parts alter their shape. Anything which hinders free heat expansion will give rise to heat stresses. Design rules are thus obtained for the heated walls themselves as well as for the adjoining parts. An important guiding principle is that of designing the heat-conducting walls as thin as possible.

A high-threshold heat-activated channel in cultured rat dorsal root ganglion neurons resembles TRPV2 and is blocked by gadolinium.

PubMed

Leffler, Andreas; Linte, Ramona Madalina; Nau, Carla; Reeh, Peter; Babes, Alexandru

2007-07-01

Heat-activated ion channels from the vanilloid-type TRP group (TRPV1-4) seem to be central for heat-sensitivity of nociceptive sensory neurons. Displaying a high-threshold (> 52 degrees C) for activation, TRPV2 was proposed to act as a sensor for intense noxious heat in mammalian sensory neurons. However, although TRPV2 is expressed in a distinct population of thinly myelinated primary afferents, a widespread expression in a variety of neuronal and non-neuronal tissues suggests a more diverse physiological role of TRPV2. In its role as a heat-sensor, TRPV2 has not been thoroughly characterized in terms of biophysical and pharmacological properties. In the present study, we demonstrate that the features of heterologously expressed rat TRPV2 closely resemble those of high-threshold heat-evoked currents in medium- and large-sized capsaicin-insensitive rat dorsal root ganglion (DRG) neurons. Both in TRPV2-expressing human embryonic kidney (HEK)293t cells and in DRGs, high-threshold heat-currents were sensitized by repeated activation and by the TRPV1-3 agonist, 2-aminoethoxydiphenyl borate (2-APB). In addition to a previously described block by ruthenium red, we identified the trivalent cations, lanthanum (La(3+)) and gadolinium (Gd(3+)) as potent blockers of TRPV2. Thus, we present a new pharmacological tool to distinguish between heat responses of TRPV2 and the closely related capsaicin-receptor, TRPV1, which is strongly sensitized by trivalent cations. We demonstrate that self-sensitization of heat-evoked currents through TRPV2 does not require extracellular calcium and that TRPV2 can be activated in cell-free membrane patches in the outside-out configuration. Taken together our results provide new evidence for a role of TRPV2 in mediating high-threshold heat responses in a subpopulation of mammalian sensory neurons.

Thermal Aspects of Lithium Ion Cells

NASA Technical Reports Server (NTRS)

Frank, H.; Shakkottai, P.; Bugga, R.; Smart, M.; Huang, C. K.; Timmerman, P.; Surampudi, S.

2000-01-01

This viewgraph presentation outlines the development of a thermal model of Li-ion cells in terms of heat generation, thermal mass, and thermal resistance. Intended for incorporation into battery model. The approach was to estimate heat generation: with semi-theoretical model, and then to check accuracy with efficiency measurements. Another objective was to compute thermal mass from component weights and specific heats, and to compute the thermal resistance from component dimensions and conductivities. Two lithium batteries are compared, the Cylindrical lithium battery, and the prismatic lithium cell. It reviews methodology for estimating the heat generation rate. Graphs of the Open-circuit curves of the cells and the heat evolution during discharge are given.

Nuclear reactor insulation and preheat system

DOEpatents

Wampole, Nevin C.

1978-01-01

An insulation and preheat system for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the compartment. An external surface of the compartment or enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair.

Heat pipe solar receiver with thermal energy storage

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.

1981-01-01

An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

A leading edge heating array and a flat surface heating array - operation, maintenance and repair manual

NASA Technical Reports Server (NTRS)

1975-01-01

A general description of the leading edge/flat surface heating array is presented along with its components, assembly instructions, installation instructions, operation procedures, maintenance instructions, repair procedures, schematics, spare parts lists, engineering drawings of the array, and functional acceptance test log sheets. The proper replacement of components, correct torque values, step-by-step maintenance instructions, and pretest checkouts are described.

Method for estimating off-axis pulse tube losses

NASA Astrophysics Data System (ADS)

Fang, T.; Mulcahey, T. I.; Taylor, R. P.; Spoor, P. S.; Conrad, T. J.; Ghiaasiaan, S. M.

2017-12-01

Some Stirling-type pulse tube cryocoolers (PTCs) exhibit sensitivity to gravitational orientation and often exhibit significant cooling performance losses unless situated with the cold end pointing downward. Prior investigations have indicated that some coolers exhibit sensitivity while others do not; however, a reliable method of predicting the level of sensitivity during the design process has not been developed. In this study, we present a relationship that estimates an upper limit to gravitationally induced losses as a function of the dimensionless pulse tube convection number (NPTC) that can be used to ensure that a PTC would remain functional at adverse static tilt conditions. The empirical relationship is based on experimental data as well as experimentally validated 3-D computational fluid dynamics simulations that examine the effects of frequency, mass flow rate, pressure ratio, mass-pressure phase difference, hot and cold end temperatures, and static tilt angle. The validation of the computational model is based on experimental data collected from six commercial pulse tube cryocoolers. The simulation results are obtained from component-level models of the pulse tube and heat exchangers. Parameter ranges covered in component level simulations are 0-180° for tilt angle, 4-8 for length to diameter ratios, 4-80 K cold tip temperatures, -30° to +30° for mass flow to pressure phase angles, and 25-60 Hz operating frequencies. Simulation results and experimental data are aggregated to yield the relationship between inclined PTC performance and pulse tube convection numbers. The results indicate that the pulse tube convection number can be used as an order of magnitude indicator of the orientation sensitivity, but CFD simulations should be used to calculate the change in energy flow more accurately.

Highly sensitive detection of individual HEAT and ARM repeats with HHpred and COACH.

PubMed

Kippert, Fred; Gerloff, Dietlind L

2009-09-24

HEAT and ARM repeats occur in a large number of eukaryotic proteins. As these repeats are often highly diverged, the prediction of HEAT or ARM domains can be challenging. Except for the most clear-cut cases, identification at the individual repeat level is indispensable, in particular for determining domain boundaries. However, methods using single sequence queries do not have the sensitivity required to deal with more divergent repeats and, when applied to proteins with known structures, in some cases failed to detect a single repeat. Testing algorithms which use multiple sequence alignments as queries, we found two of them, HHpred and COACH, to detect HEAT and ARM repeats with greatly enhanced sensitivity. Calibration against experimentally determined structures suggests the use of three score classes with increasing confidence in the prediction, and prediction thresholds for each method. When we applied a new protocol using both HHpred and COACH to these structures, it detected 82% of HEAT repeats and 90% of ARM repeats, with the minimum for a given protein of 57% for HEAT repeats and 60% for ARM repeats. Application to bona fide HEAT and ARM proteins or domains indicated that similar numbers can be expected for the full complement of HEAT/ARM proteins. A systematic screen of the Protein Data Bank for false positive hits revealed their number to be low, in particular for ARM repeats. Double false positive hits for a given protein were rare for HEAT and not at all observed for ARM repeats. In combination with fold prediction and consistency checking (multiple sequence alignments, secondary structure prediction, and position analysis), repeat prediction with the new HHpred/COACH protocol dramatically improves prediction in the twilight zone of fold prediction methods, as well as the delineation of HEAT/ARM domain boundaries. A protocol is presented for the identification of individual HEAT or ARM repeats which is straightforward to implement. It provides high sensitivity at a low false positive rate and will therefore greatly enhance the accuracy of predictions of HEAT and ARM domains.

Highly Sensitive Detection of Individual HEAT and ARM Repeats with HHpred and COACH

PubMed Central

Kippert, Fred; Gerloff, Dietlind L.

2009-01-01

Background HEAT and ARM repeats occur in a large number of eukaryotic proteins. As these repeats are often highly diverged, the prediction of HEAT or ARM domains can be challenging. Except for the most clear-cut cases, identification at the individual repeat level is indispensable, in particular for determining domain boundaries. However, methods using single sequence queries do not have the sensitivity required to deal with more divergent repeats and, when applied to proteins with known structures, in some cases failed to detect a single repeat. Methodology and Principal Findings Testing algorithms which use multiple sequence alignments as queries, we found two of them, HHpred and COACH, to detect HEAT and ARM repeats with greatly enhanced sensitivity. Calibration against experimentally determined structures suggests the use of three score classes with increasing confidence in the prediction, and prediction thresholds for each method. When we applied a new protocol using both HHpred and COACH to these structures, it detected 82% of HEAT repeats and 90% of ARM repeats, with the minimum for a given protein of 57% for HEAT repeats and 60% for ARM repeats. Application to bona fide HEAT and ARM proteins or domains indicated that similar numbers can be expected for the full complement of HEAT/ARM proteins. A systematic screen of the Protein Data Bank for false positive hits revealed their number to be low, in particular for ARM repeats. Double false positive hits for a given protein were rare for HEAT and not at all observed for ARM repeats. In combination with fold prediction and consistency checking (multiple sequence alignments, secondary structure prediction, and position analysis), repeat prediction with the new HHpred/COACH protocol dramatically improves prediction in the twilight zone of fold prediction methods, as well as the delineation of HEAT/ARM domain boundaries. Significance A protocol is presented for the identification of individual HEAT or ARM repeats which is straightforward to implement. It provides high sensitivity at a low false positive rate and will therefore greatly enhance the accuracy of predictions of HEAT and ARM domains. PMID:19777061

Integral modeling and financial impact of the geothermal situation and power plant at Soultz-sous-Forêts

NASA Astrophysics Data System (ADS)

Heidinger, Philipp

2010-07-01

The science about deep Enhanced Geothermal Systems (EGS) is still an emerging process and for further spreading economics is the key of the technology. To understand the financial situation, a program for economic evaluation was developed. This software (Euronaut) is completely modularized and considers all cash flows. Projects like an EGS are wrapped into tree-like structures. Based on the results which were gained at Soultz-sous-Forêts, two configurations were designed. The first EGS configuration consists of a simplified two well (doublet) system where the dependencies of all components (mainly the reservoir, wells, pumps and the heat-to-power conversion unit) are physically and economically linked together. The realization of these dependencies and their complex interactions enable a sensitivity analysis of the borehole depth and reservoir depth, respectively. As a result, depth dependent effective costs and revenues of an EGS plant with the geohydrological characteristics of Soultz-sous-Forêts are determined. As a future development, the second configuration will adapt the actual situation at Soultz-sous-Forêts with the individual features of all four wells (GPK1 - GPK4). Then, this model can be used for all kinds of sensitivity analyses to clarify the impact of certain components or to optimize the operation scheme; e.g. the flow rates.

Global map of heat flow on a 2 degree grid - digitally available

NASA Astrophysics Data System (ADS)

Davies, J. Huw

2014-05-01

A global map of surface heat flow is developed on a 2° by 2° equal area grid, and is made available digitally. It is based on a global heat flow data set of over 38,000 measurements, very similar to that used in Davies & Davies (2010). The map consists of three components. Firstly, in regions of young ocean crust (<67.7Ma) the model estimate uses a half-space conduction model based on the age of the oceanic crust, using parameters of Jaupart et al., (2007). This is done since it is well known that raw data measurements are frequently influenced by significant hydrothermal circulation. Secondly in other regions of data coverage the estimate is based on data measurements. At the map resolution these two categories (young ocean, data covered) cover 65% of Earth's surface. The estimate has been developed in two different ways. In one way the mean value is used and in the second the median is used. The median estimate might be expected to be less sensitive to outliers. Thirdly, for all other regions the estimate is based on the assumption that there is a correlation between heat-flow and geology. This is undertaken using the CCGM (2000) digital geology map. This assumption is assessed and the correlation is found to provide a minor improvement over assuming that heat flow would be represented by the global average. The estimate for Antarctica is guided by proxy measurements. All the work is undertaken using GIS methods. Estimates are made of the errors for all components. The results have been made available as digital files, including shapefiles and tab-delimited and csv ASCII files. In addition to the equal area grid, the results are also available on an equal longitude grid. The map has been published -Davies (2013). The digital files are available in the supplementary information of the publication. Commission for the Geological Map of the World (2000), Geological Map of the World at 1:25000000, UNESCO/CCGM, Paris. Davies, JH, (2013) A global map of solid Earth surface heat flow, Geochemistry, Geophysics and Geosystems, 14, 4608-4622, doi 10.1002/ggge.20271. Davies JH & Davies DR, (2010) Earth's surface heat flux, Solid Earth, 1, 5-24, www.solid-earth.net/1/5/2010/. Jaupart C, Labrosse S, Mareschal J-C, (2007) Temperatures, heat and energy in the mantle of the Earth, in Treatise on Geophysics, v7 Mantle Convection, ed D. Bercovici, 253-303, Elsevier, Amsterdam

Development of a heat vulnerability index for New York State.

PubMed

Nayak, S G; Shrestha, S; Kinney, P L; Ross, Z; Sheridan, S C; Pantea, C I; Hsu, W H; Muscatiello, N; Hwang, S A

2017-12-01

The frequency and intensity of extreme heat events are increasing in New York State (NYS) and have been linked with increased heat-related morbidity and mortality. But these effects are not uniform across the state and can vary across large regions due to regional sociodemographic and environmental factors which impact an individual's response or adaptive capacity to heat and in turn contribute to vulnerability among certain populations. We developed a heat vulnerability index (HVI) to identify heat-vulnerable populations and regions in NYS. Census tract level environmental and sociodemographic heat-vulnerability variables were used to develop the HVI to identify heat-vulnerable populations and areas. Variables were identified from a comprehensive literature review and climate-health research in NYS. We obtained data from 2010 US Census Bureau and 2011 National Land Cover Database. We used principal component analysis to reduce correlated variables to fewer uncorrelated components, and then calculated the cumulative HVI for each census tract by summing up the scores across the components. The HVI was then mapped across NYS (excluding New York City) to display spatial vulnerability. The prevalence rates of heat stress were compared across HVI score categories. Thirteen variables were reduced to four meaningful components representing 1) social/language vulnerability; 2) socioeconomic vulnerability; 3) environmental/urban vulnerability; and 4) elderly/ social isolation. Vulnerability to heat varied spatially in NYS with the HVI showing that metropolitan areas were most vulnerable, with language barriers and socioeconomic disadvantage contributing to the most vulnerability. Reliability of the HVI was supported by preliminary results where higher rates of heat stress were collocated in the regions with the highest HVI. The NYS HVI showed spatial variability in heat vulnerability across the state. Mapping the HVI allows quick identification of regions in NYS that could benefit from targeted interventions. The HVI will be used as a planning tool to help allocate appropriate adaptation measures like cooling centers and issue heat alerts to mitigate effects of heat in vulnerable areas. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lunar base heat pump, phase 1

NASA Technical Reports Server (NTRS)

Goldman, Jeffrey H.; Harvey, A.; Lovell, T.; Walker, David H.

1994-01-01

This report describes the Phase 1 process and analysis used to select a refrigerant and thermodynamic cycle as the basis of a vapor compression heat pump requiring a high temperature lift, then to perform a preliminary design to implement the selected concept, including major component selection. Use of a vapor compression heat pump versus other types was based on prior work performed for the Electric Power Research Institute. A high lift heat pump is needed to enable a thermal control system to remove heat down to 275 K from a habitable volume when the external thermal environment is severe. For example, a long-term lunar base habitat will reject heat from a space radiator to a 325 K environment. The first step in the selection process was to perform an optimization trade study, quantifying the effect of radiator operating temperature and heat pump efficiency on total system mass; then, select the radiator operating temperature corresponding to the lowest system mass. Total system mass included radiators, all heat pump components, and the power supply system. The study showed that lunar night operation, with no temperature lift, dictated the radiator size. To operate otherwise would require a high mass penalty to store power. With the defined radiation surface, and heat pump performances assumed to be from 40 percent to 60 percent of the Carnot ideal, the optimum heat rejection temperature ranged from 387 K to 377 K, as a function of heat pump performance. Refrigerant and thermodynamic cycles were then selected to best meet the previously determined design conditions. The system was then adapted as a ground-based prototype lifting temperature to 360 K (versus 385 K for flight unit) and using readily available commercial-grade components. Over 40 refrigerants, separated into wet and dry compression behavioral types, were considered in the selection process. Refrigerants were initially screened for acceptable critical temperature. The acceptable refrigerants were analyzed in ideal single and two-stage thermodynamic cycles. Top candidates were analyzed assuming realistic component limits and system pressure drops, and were evaluated for other considerations such as safety, environmental impact, and commercial availability. A maximum coefficient of performance (COP) of 56 percent of the Carnot ideal was achievable for a three-stage CFC-11 cycle operating under the flight conditions above. The program was completed by defining a control scheme and by researching and selecting the major components, compressor and heat exchangers, that could be used to implement the thermodynamic cycle selected. Special attention was paid to using similar technologies for the SIRF and flight heat pumps resulting in the commercially available equivalent of the flight unit. A package concept was generated for the components selected and mass and volume estimated.

A Method to Estimate Fabric Particle Penetration Performance

DTIC Science & Technology

2014-09-08

may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test. The ability to predict multi-layered...within the fabric/component gap may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test...impermeable garment . Heat stress becomes a major problem with this approach however, as normal physiological heat loss mechanisms (especially sweat

The 2010 Russian Drought Impact on Satellite Measurements of Solar-Induced Chlorophyll Fluorescence: Insights from Modeling and Comparisons with the Normalized Differential Vegetation Index (NDVI)

NASA Technical Reports Server (NTRS)

Yoshida, Y.; Joiner, J.; Tucker, C.; Berry, J.; Lee, J. -E.; Walker, G.; Reichle, R.; Koster, R.; Lyapustin, A.; Wang, Y.

2015-01-01

We examine satellite-based measurements of chlorophyll solar-induced fluorescence (SIF) over the region impacted by the Russian drought and heat wave of 2010. Like the popular Normalized Difference Vegetation Index (NDVI) that has been used for decades to measure photosynthetic capacity, SIF measurements are sensitive to the fraction of absorbed photosynthetically-active radiation (fPAR). However, in addition, SIF is sensitive to the fluorescence yield that is related to the photosynthetic yield. Both SIF and NDVI from satellite data show drought-related declines early in the growing season in 2010 as compared to other years between 2007 and 2013 for areas dominated by crops and grasslands. This suggests an early manifestation of the dry conditions on fPAR. We also simulated SIF using a global land surface model driven by observation-based meteorological fields. The model provides a reasonable simulation of the drought and heat impacts on SIF in terms of the timing and spatial extents of anomalies, but there are some differences between modeled and observed SIF. The model may potentially be improved through data assimilation or parameter estimation using satellite observations of SIF (as well as NDVI). The model simulations also offer the opportunity to examine separately the different components of the SIF signal and relationships with Gross Primary Productivity (GPP).

Capabilities of a New Pressure Controller for Gas-Controlled Heat Pipes

NASA Astrophysics Data System (ADS)

Giunta, S.; Merlone, A.; Marenco, S.; Marcarino, P.; Tiziani, A.

2008-10-01

Pressure control is used in many metrological applications and for the control of thermodynamic quantities. At the Italian National Research Institute of Metrology (INRiM), a new pressure controller has been designed and assembled, operating in the pressure range between 4 kPa and 400 kPa. This innovative instrument uses a commercial pressure transducer with a sensitivity of 10-4 and several electro-valves interposed among calibrated volumes of different dimensions in order to realize known ratios for very fine pressure changes. The device is provided with several circuits to drive the electro-valve actions, for signal processing and transmission, and for both manual and automatic control. Input/output peripherals, such as a 4 × 20 dot matrix display and a 4 × 4 keyboard, allow setting of the parameters and data visualization, while a remote control port allows interfacing with a computer. The operating principle of this pressure controller has been recently applied, with excellent results, to control the pressure in gas-controlled heat pipes by using a standard platinum resistance thermometer as a temperature/pressure sensor, achieving in this case a relative sensitivity better than 10-6 in pressure. Several tests were also made to control the pressure by means of a commercial sensor. The device, its main components, and its capabilities are here reported, together with application tests and results.

Partitioning of sublimation and evaporation from Lake Bonney using water vapor isotope and latent heat fluxes

NASA Astrophysics Data System (ADS)

Bellagamba, A. W.; Berkelhammer, M. B.; Winslow, L.; Peter, D.; Myers, K. F.

2017-12-01

The landscapes of the McMurdo Dry Valleys in Antarctica are characterized by a series of frozen lakes. Although the conditions in this region are severe, the lakes share common characteristics with lakes at glacial termini elsewhere. Geochemical and geomorphological evidence suggest these lakes have experienced large historical changes indicative of changes water balances. While part of these shifts in lake volume arise from changes in glacial inflow, they likely also reflect changes in the latent heat flux from the lake surfaces. Here we present a joint analysis of the stable isotopic ratio of surface ice/water and the water vapor flux over Dry Valley frozen lakes to ascertain the processes controlling water losses from the lake surfaces. We compare the isotopic ratio of the latent heat flux with the surface water isotopes to derive a fractionation factor associated with latent flux. This data is then used to provide insight into how much of the water vapor flux is sublimated versus evaporated, as well as how the sublimation and evaporative components of the flux change with synoptic weather. We used a Picarro L2130-I isotopic water analyzer to measure humidity and the isotopic ratio of water vapor at three heights over Lake Bonney in Taylor Valley, Antarctica and used the flux-gradient approach to convert the isotopic ratio of the vapor to an "isoflux". An on-site meteorological station recorded temperature, relative humidity and wind direction/intensity at two different heights above the lake and an infrared radiometer recorded lake skin temperature. These data were used to calculate the sensible and latent heat fluxes. The fractionation factor was close to 0, which indicates that sublimation was the primary component of the flux although evaporation became increasingly prominent following a katabatic wind event. The results suggest this technique could be an effective tool to study the sensitivity of latent heat fluxes to weather here and in other similar environments. The trial run performed at Lake Bonney in November-December 2016 was performed as part of the ongoing LTER (Long Term Ecological Research) project at the McMurdo Dry Valleys and a second experiment will be performed in January 2018.

Conceptual design of a thermalhydraulic loop for multiple test geometries at supercritical conditions named Supercritical Phenomena Experimental Test Apparatus (SPETA)

NASA Astrophysics Data System (ADS)

Adenariwo, Adepoju

The efficiency of nuclear reactors can be improved by increasing the operating pressure of current nuclear reactors. Current CANDU-type nuclear reactors use heavy water as coolant at an outlet pressure of up to 11.5 MPa. Conceptual SuperCritical Water Reactors (SCWRs) will operate at a higher coolant outlet pressure of 25 MPa. Supercritical water technology has been used in advanced coal plants and its application proves promising to be employed in nuclear reactors. To better understand how supercritical water technology can be applied in nuclear power plants, supercritical water loops are used to study the heat transfer phenomena as it applies to CANDU-type reactors. A conceptual design of a loop known as the Supercritical Phenomena Experimental Apparatus (SPETA) has been done. This loop has been designed to fit in a 9 m by 2 m by 2.8 m enclosure that will be installed at the University of Ontario Institute of Technology Energy Research Laboratory. The loop include components to safely start up and shut down various test sections, produce a heat source to the test section, and to remove reject heat. It is expected that loop will be able to investigate the behaviour of supercritical water in various geometries including bare tubes, annulus tubes, and multi-element-type bundles. The experimental geometries are designed to match the fluid properties of Canadian SCWR fuel channel designs so that they are representative of a practical application of supercritical water technology in nuclear plants. This loop will investigate various test section orientations which are the horizontal, vertical, and inclined to investigate buoyancy effects. Frictional pressure drop effects and satisfactory methods of estimating hydraulic resistances in supercritical fluid shall also be estimated with the loop. Operating limits for SPETA have been established to be able to capture the important heat transfer phenomena at supercritical conditions. Heat balance and flow calculations have been done to appropriately size components in the loop. Sensitivity analysis has been done to find the optimum design for the loop.

Nonlinear ultrasonic stimulated thermography for damage assessment in isotropic fatigued structures

NASA Astrophysics Data System (ADS)

Fierro, Gian Piero Malfense; Calla', Danielle; Ginzburg, Dmitri; Ciampa, Francesco; Meo, Michele

2017-09-01

Traditional non-destructive evaluation (NDE) and structural health monitoring (SHM) systems are used to analyse that a structure is free of any harmful damage. However, these techniques still lack sensitivity to detect the presence of material micro-flaws in the form of fatigue damage and often require time-consuming procedures and expensive equipment. This research work presents a novel "nonlinear ultrasonic stimulated thermography" (NUST) method able to overcome some of the limitations of traditional linear ultrasonic/thermography NDE-SHM systems and to provide a reliable, rapid and cost effective estimation of fatigue damage in isotropic materials. Such a hybrid imaging approach combines the high sensitivity of nonlinear acoustic/ultrasonic techniques to detect micro-damage, with local defect frequency selection and infrared imaging. When exciting structures with an optimised frequency, nonlinear elastic waves are observed and higher frictional work at the fatigue damaged area is generated due to clapping and rubbing of the crack faces. This results in heat at cracked location that can be measured using an infrared camera. A Laser Vibrometer (LV) was used to evaluate the extent that individual frequency components contribute to the heating of the damage region by quantifying the out-of-plane velocity associated with the fundamental and second order harmonic responses. It was experimentally demonstrated the relationship between a nonlinear ultrasound parameter (βratio) of the material nonlinear response to the actual temperature rises near the crack. These results demonstrated that heat generation at damaged regions could be amplified by exciting at frequencies that provide nonlinear responses, thus improving the imaging of material damage and the reliability of NUST in a quick and reproducible manner.

Eugenol and carvacrol excite first- and second-order trigeminal neurons and enhance their heat-evoked responses

PubMed Central

Klein, Amanda H.; Joe, Christopher L.; Davoodi, Auva; Takechi, Kenichi; Carstens, Mirela Iodi; Carstens, E

2014-01-01

Eugenol and carvacrol from clove and oregano, respectively, are agonists of the warmth-sensitive transient receptor potential channel TRPV3 and the irritant-sensitive TRPA1. Eugenol and carvacrol induce oral irritation that rapidly desensitizes, accompanied by brief enhancement of innocuous warmth and heat pain in humans. We presently investigated if eugenol and carvacrol activate nociceptive primary afferent and higher-order trigeminal neurons and enhance their heat-evoked responses, using calcium imaging of cultured trigeminal ganglion (TG) and dorsal root ganglion (DRG) neurons, and in vivo single-unit recordings in trigeminal subnucleus caudalis (Vc) of rats. Eugenol and carvacrol activated 20-30% of TG and 7-20% of DRG cells, the majority of which additionally responded to menthol, mustard oil and/or capsaicin. TG cell responses to innocuous (39°) and noxious (42°C) heating were enhanced by eugenol and carvacrol. We identified dorsomedial Vc neurons responsive to noxious heating of the tongue in pentobarbital-anesthetized rats. Eugenol and carvacrol dose-dependently elicited desensitizing responses in 55% and 73% of heat-sensitive units, respectively. Responses to noxious heat were briefly enhanced by eugenol and carvacrol. Many eugenol- and carvacrol-responsive units also responded to menthol, cinnamaldehyde and capsaicin. These data support a peripheral site for eugenol and carvacrol to enhance warmth- and noxious heat-evoked responses of trigeminal neurons, and are consistent with the observation that these agonists briefly enhance warmth and heat pain on the human tongue. PMID:24759772

Two-layer convective heating prediction procedures and sensitivities for blunt body reentry vehicles

NASA Technical Reports Server (NTRS)

Bouslog, Stanley A.; An, Michael Y.; Wang, K. C.; Tam, Luen T.; Caram, Jose M.

1993-01-01

This paper provides a description of procedures typically used to predict convective heating rates to hypersonic reentry vehicles using the two-layer method. These procedures were used to compute the pitch-plane heating distributions to the Apollo geometry for a wind tunnel test case and for three flight cases. Both simple engineering methods and coupled inviscid/boundary layer solutions were used to predict the heating rates. The sensitivity of the heating results in the choice of metrics, pressure distributions, boundary layer edge conditions, and wall catalycity used in the heating analysis were evaluated. Streamline metrics, pressure distributions, and boundary layer edge properties were defined from perfect gas (wind tunnel case) and chemical equilibrium and nonequilibrium (flight cases) inviscid flow-field solutions. The results of this study indicated that the use of CFD-derived metrics and pressures provided better predictions of heating when compared to wind tunnel test data. The study also showed that modeling entropy layer swallowing and ionization had little effect on the heating predictions.

P2X₇ receptor of rat dorsal root ganglia is involved in the effect of moxibustion on visceral hyperalgesia.

PubMed

Liu, Shuangmei; Shi, Qingming; Zhu, Qicheng; Zou, Ting; Li, Guilin; Huang, An; Wu, Bing; Peng, Lichao; Song, Miaomiao; Wu, Qin; Xie, Qiuyu; Lin, Weijian; Xie, Wei; Wen, Shiyao; Zhang, Zhedong; Lv, Qiulan; Zou, Lifang; Zhang, Xi; Ying, Mofeng; Li, Guodong; Liang, Shangdong

2015-06-01

Irritable bowel syndrome (IBS) and inflammatory bowel disease often display visceral hypersensitivity. Visceral nociceptors after inflammatory stimulation generate afferent nerve impulses through dorsal root ganglia (DRG) transmitting to the central nervous system. ATP and its activated-purinergic 2X7 (P2X7) receptor play an important role in the transmission of nociceptive signal. Purinergic signaling is involved in the sensory transmission of visceral pain. Moxibustion is a therapy applying ignited mugwort directly or indirectly at acupuncture points or other specific parts of the body to treat diseases. Heat-sensitive acupoints are the corresponding points extremely sensitive to moxa heat in disease conditions. In this study, we aimed to investigate the relationship between the analgesic effect of moxibustion on a heat-sensitive acupoint "Dachangshu" and the expression levels of P2X7 receptor in rat DRG after chronic inflammatory stimulation of colorectal distension. Heat-sensitive moxibustion at Dachangshu acupoint inhibited the nociceptive signal transmission by decreasing the upregulated expression levels of P2X7 mRNA and protein in DRG induced by visceral pain, and reversed the abnormal expression of glial fibrillary acidic protein (GFAP, a marker of satellite glial cells) in DRG. Consequently, abdominal withdrawal reflex (AWR) score in a visceral pain model was reduced, and the pain threshold was elevated. Therefore, heat-sensitive moxibustion at Dachangshu acupoint can produce a therapeutic effect on IBS via inhibiting the nociceptive transmission mediated by upregulated P2X7 receptor.

Topical hindpaw application of L-menthol decreases responsiveness to heat with biphasic effects on cold sensitivity of rat lumbar dorsal horn neurons

PubMed Central

Klein, Amanda H.; Sawyer, Carolyn M.; Takechi, Kenichi; Davoodi, Auva; Ivanov, Margaret A.; Carstens, Mirela Iodi; Carstens, E

2012-01-01

Menthol is used in pharmaceutical applications because of its desired cooling and analgesic properties. The neural mechanism by which topical application of menthol decreases heat pain is not fully understood. We investigated the effects of topical menthol application on lumbar dorsal horn wide dynamic range and nociceptive-specific neuronal responses to noxious heat and cooling of glaborous hindpaw cutaneous receptive fields. Menthol increased thresholds for responses to noxious heat in a concentration-dependent manner. Menthol had a biphasic effect on cold-evoked responses, reducing the threshold (to warmer temperatures) at a low (1%) concentration and increasing threshold and reducing response magnitude at high (10, 40%) concentrations. Menthol had little effect on responses to innocuous or noxious mechanical stimuli, ruling out a local anesthetic action. Application of 40% menthol to the contralateral hindpaw tended to reduce responses to cooling and noxious heat, suggesting a weak heterosegmental inhibitory effect. These results indicate that menthol has an analgesic effect on heat sensitivity of nociceptive dorsal horn neurons, as well as biphasic effects on cold sensitivity, consistent with previous behavioral observations. PMID:22687951

Experimental determination of the key heat transfer mechanisms in pharmaceutical freeze-drying.

PubMed

Ganguly, Arnab; Nail, Steven L; Alexeenko, Alina

2013-05-01

The study is aimed at quantifying the relative contribution of key heat transfer modes in lyophilization. Measurements of vial heat transfer rates in a laboratory-scale freeze-dryer were performed using pure water, which was partially sublimed under various conditions. The separation distance between the shelf and the vial was systematically varied, and sublimation rates were determined gravimetrically. The heat transfer rates were observed to be independent of separation distance between the vial and the shelf and linearly dependent on pressure in the free molecular flow limit, realized at low pressures (<50 mTorr). However, under higher pressures (>120 mTorr), heat transfer rates were independent of pressure and inversely proportional to separation distance. Previous heat transfer studies in conventional freeze-drying cycles have attributed a dominant portion of the total heat transfer to radiation, the rest to conduction, whereas convection has been found to be insignificant. Although the measurements reported here confirm the significance of the radiative and gas conduction components, the convective component has been found to be comparable to the gas conduction contribution at pressures greater than 100 mTorr. The current investigation supports the conclusion that the convective component of the heat transfer cannot be ignored in typical laboratory-scale freeze-drying conditions. Copyright © 2013 Wiley Periodicals, Inc.

Installation guidelines for solar heating system, single-family residence at New Castle, Pennsylvania

NASA Technical Reports Server (NTRS)

1980-01-01

The solar heating system installer guidelines are presented for each subsystem. This single family residential heating system is a solar-assisted, hydronic-to-warm-air system with solar-assisted domestic water heating. It is composed of the following major components: (1) liquid cooled flat plate collectors; (2) water storage tank; (3) passive solar-fired domestic water preheater; (4) electric hot water heater; (5) heat pump with electric backup; (6) solar hot water coil unit; (7) tube-and-shell heat exchanger, three pumps, and associated pipes and valving in an energy transport module; (8) control system; and (9) air-cooled heat purge unit. Information is provided on the operating procedures, controls, caution requirements, and routine and schedule maintenance in the form of written descriptions, schematics, detail drawings, pictures, and manufacturer's component data.

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems

DTIC Science & Technology

1991-05-01

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems by Edgar S. Neely Robert D. Neathammer...Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems RDTE dated 1980EIMB 1984 - 1989 6. AUTHOR(S) Edgar S. Neely, Robert D...Laboratory (USACERL). The Principal Investigators were Dr. Edgar Neely and Mr. Robert Neathammer (USACERL-FS). The primary contractor for much of the

Cold weather hydrogen generation system and method of operation

DOEpatents

Dreier, Ken Wayne; Kowalski, Michael Thomas; Porter, Stephen Charles; Chow, Oscar Ken; Borland, Nicholas Paul; Goyette, Stephen Arthur

2010-12-14

A system for providing hydrogen gas is provided. The system includes a hydrogen generator that produces gas from water. One or more heat generation devices are arranged to provide heating of the enclosure during different modes of operation to prevent freezing of components. A plurality of temperature sensors are arranged and coupled to a controller to selectively activate a heat source if the temperature of the component is less than a predetermined temperature.

2La chromosomal inversion enhances thermal tolerance of Anopheles gambiae larvae.

PubMed

Rocca, Kyle A C; Gray, Emilie M; Costantini, Carlo; Besansky, Nora J

2009-07-02

The mosquito Anopheles gambiae is broadly distributed throughout sub-Saharan Africa and this contributes to making it the most efficient vector of malaria on the continent. The pervasiveness of this species is hypothesized to originate in local adaptations facilitated by inversion polymorphisms. One inversion, named 2La, is strongly associated with aridity clines in West and Central Africa: while 2La is fixed in arid savannas, the 2L+a arrangement is predominantly found in the rainforest. Ability to survive high temperature exposure is an essential component of aridity tolerance, particularly in immature stages that are restricted to shallow puddles. Toward deciphering the role of the 2La inversion in local adaptation, the present investigation focused on variation in larval and pupal thermo-tolerance in two populations dissimilar solely in 2La arrangement. A laboratory colony of A. gambiae that is polymorphic for 2La but standard for all other known inversions was used to create 2 homokaryotypic populations (2L+a and 2La). The survival of 4th instar larvae and pupae from both populations was then tested following exposure to thermal stress with and without prior heat hardening. Larvae responded identically to a 40 degrees C heat stress, with about 50% of larvae dying after 1.5-2 h and few larvae surviving a 3 h stress. When heat hardened prior to the thermal stress, thermo-tolerance of both larval populations increased, with 2La 24 h survival significantly exceeding that of 2L+a. Pupae were generally more thermo-tolerant than larvae, although 2La pupae were less so than 2L+a. Heat hardening had no positive effect on pupal thermo-tolerance. The increased thermo-tolerance observed in 2La larvae following heat hardening suggests higher responsiveness (i.e., thermal sensitivity) of the inverted karyotype. By responding more drastically to the heat shock, 2La larvae are better equipped to resist the potentially lethal temperatures that occur in arid habitats. The lower survival of 2La pupae compared with 2L+a may reflect the cost of this sensitivity, whereby the thermal resistance mechanisms prevent successful completion of metamorphosis. The costs and benefits of thermal resistance are discussed in light of the climates characterizing either end of the 2La frequency cline.

Analysis of feline and canine allergen components in patients sensitized to pets.

PubMed

Ukleja-Sokołowska, Natalia; Gawrońska-Ukleja, Ewa; Żbikowska-Gotz, Magdalena; Socha, Ewa; Lis, Kinga; Sokołowski, Łukasz; Kuźmiński, Andrzej; Bartuzi, Zbigniew

2016-01-01

Component resolved allergen diagnosis allows for a precise evaluation of the sensitization profiles of patients sensitized to felines and canines. An accurate interpretation of these results allows better insight into the evolution of a given patients sensitizations, and allows for a more precise evaluation of their prognoses. 70 patients (42 women and 28 men, aged 18-65, with the average of 35.5) with a positive feline or canine allergy diagnosis were included in the research group. 30 patients with a negative allergy diagnosis were included in the control group. The total IgE levels of all patients with allergies as well as their allergen-specific IgE to feline and canine allergens were measured. Specific IgE levels to canine (Can f 1, Can f 2, Can f 3, Can f 5) and feline (Fel d 1, Fel d 2, Fel d 4) allergen components were also measured with the use of the ImmunoCap method. Monosensitization for only one canine or feline component was found in 30% of patients. As predicted, the main feline allergen was Fel d 1, which sensitized as many as 93.9% of patients sensitized to felines. Among 65 patients sensitized to at least one feline component, for 30 patients (46.2%) the only sensitizing feline component was Fel d 1. Only 19 patients in that group (63.3%) were not simultaneously sensitized to dogs and 11 (36.7%), the isolated sensitization to feline Fel d 1 notwithstanding, displayed concurrent sensitizations to one of the canine allergen components. Fel d 4 sensitized 49.2% of the research group.64.3% of patients sensitized to canine components had heightened levels of specific IgE to Can f 1. Monosensitization in that group occurred for 32.1% of the patients. Sensitization to Can f 5 was observed among 52.4% of the patients. Concurrent sensitizations to a few allergic components, not only cross-reactive but also originating in different protein families, are a significant problem for patients sensitized to animals.

Variations in the radiation sensitivity of foodborne pathogens associated with complex ready-to-eat food products

NASA Astrophysics Data System (ADS)

Sommers, Christopher H.; Boyd, Glenn

2006-07-01

Foodborne illness outbreaks and product recalls are occasionally associated with ready-to-eat (RTE) sandwiches and other "heat and eat" multi-component RTE products. Ionizing radiation can inactivate foodborne pathogens on meat and poultry, fruits and vegetables, seafood, and RTE meat products. However, less data are available on the ability of low-dose ionizing radiation, doses under 5 kGy typically used for pasteurization purposes, to inactivate pathogenic bacteria on complex multi-component food products. In this study, the efficacy of ionizing radiation to inactivate Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Yersinia enterocolitica on RTE foods including a "frankfurter on a roll", a "beef cheeseburger on a bun" and a "vegetarian cheeseburger on a bun" was investigated. The average D-10 values, the radiation dose needed to inactivate 1 log 10 of pathogen, by bacterium species, were 0.61, 0.54, 0.47, 0.36 and 0.15 kGy for Salmonella spp., S. aureus, L. monocytogenes, E. coli O157:H7, and Y. enterocolitica, respectively when inoculated onto the three product types. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens including Salmonella spp, S. aureus, L. monocytogenes, E. coli O157:H7 and Y. enterocolitica in complex RTE food products such as 'heat and eat" sandwich products.

Preliminary assessment of rover power systems for the Mars Rover Sample Return Mission

NASA Technical Reports Server (NTRS)

Bents, D. J.

1989-01-01

Four isotope power system concepts were presented and compared on a common basis for application to on-board electrical prime power for an autonomous planetary rover vehicle. A representative design point corresponding to the Mars Rover Sample Return (MRSR) preliminary mission requirements (500 W) was selected for comparison purposes. All systems concepts utilize the General Purpose Heat Source (GPHS) isotope heat source developed by DOE. Two of the concepts employ thermoelectric (TE) conversion: one using the GPHS Radioisotope Thermoelectric Generator (RTG) used as a reference case, the other using an advanced RTG with improved thermoelectric materials. The other two concepts employed are dynamic isotope power systems (DIPS): one using a closed Brayton cycle (CBC) turboalternator, and the other using a free piston Stirling cycle engine/linear alternator (FPSE) with integrated heat source/heater head. Near-term technology levels have been assumed for concept characterization using component technology figure-of-merit values taken from the published literature. For example, the CBC characterization draws from the historical test database accumulated from space Brayton cycle subsystems and components from the NASA B engine through the mini-Brayton rotating unit. TE system performance is estimated from Voyager/multihundred Watt (MHW)-RTG flight experience through Mod-RTG performance estimates considering recent advances in TE materials under the DOD/DOE/NASA SP-100 and NASA Committee on Scientific and Technological Information programs. The Stirling DIPS system is characterized from scaled-down Space Power Demonstrator Engine (SPDE) data using the GPHS directly incorporated into the heater head. The characterization/comparison results presented here differ from previous comparison of isotope power (made for LEO applications) because of the elevated background temperature on the Martian surface compared to LEO, and the higher sensitivity of dynamic systems to elevated s

Molecular Cloning and Functional Characterization of Xenopus tropicalis Frog Transient Receptor Potential Vanilloid 1 Reveal Its Functional Evolution for Heat, Acid, and Capsaicin Sensitivities in Terrestrial Vertebrates*

PubMed Central

Ohkita, Masashi; Saito, Shigeru; Imagawa, Toshiaki; Takahashi, Kenji; Tominaga, Makoto; Ohta, Toshio

2012-01-01

The functional difference of thermosensitive transient receptor potential (TRP) channels in the evolutionary context has attracted attention, but thus far little information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, which diverged earliest from terrestrial vertebrate lineages. In this study we cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by measuring changes in the intracellular calcium concentration ([Ca2+]i). The channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays ∼60% sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin induced [Ca2+]i increases in xtTRPV1-HeLa and xtDRG neurons and evoked nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low compared with mammalian orthologues. Low extracellular pH and heat activated xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes expressing xtTRPV1, inward currents were elicited by heat and low extracellular pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 561) were responsible for the low sensitivity to capsaicin. Taken together, our results indicate that xtTRPV1 functions as a polymodal receptor similar to its mammalian orthologues. The present study demonstrates that TRPV1 functions as a heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. Because it is possible to examine vanilloid and heat sensitivities in vitro and in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal for the study of TRPV1 function. PMID:22130664

Boiling on Microconfigured Composite Surfaces Enhanced

NASA Technical Reports Server (NTRS)

Chao, David F.

2000-01-01

Boiling heat transfer is one of the key technologies for the two-phase active thermal-control system used on space platforms, as well as for the dynamic power systems aboard the International Space Station. Because it is an effective heat transfer mode, boiling is integral to many space applications, such as heat exchangers and other cooling devices. Nucleate boiling near the critical heat flux (CHF) can transport very large thermal loads with a much smaller device and much lower pumping power than for single-phase heat exchangers. However, boiling performance sharply deteriorates in a reduced-gravity environment, and operation in the CHF regime is somewhat perilous because of the risk of burnout to the device surface. New materials called microconfigured metal-graphite composites can enhance boiling. The photomicrograph shows the microconfiguration (x3000) of the copper-graphite (Cu-Gr) surface as viewed by scanning electronic microscope. The graphite fiber tips appear as plateaus with rugged surfaces embedded in the copper matrix. It has been experimentally demonstrated that this type of material manifests excellent boiling heat transfer performance characteristics and an increased CHF. Nonisothermal surfaces were less sensitive to variations of wall superheat in the CHF regime. Because of the great difference in conductivity between the copper base and the graphite fiber, the composite surfaces have a nonisothermal surface characteristic and, therefore, will have a much larger "safe" operating region in the CHF regime. In addition, the thermocapillary forces induced by the temperature differences between the fiber tips and the metal matrix play an important role in bubble detachment, and may not be adversely affected in a reduced-gravity environment. All these factors indicate that microconfigured composites may improve the reliability and economy (dominant factors in all space applications) of various thermal components found on spacecraft during future missions.

Global Atmospheric Heat Distributions Observed from Space

NASA Technical Reports Server (NTRS)

Lin, Bing; Fan, Tai-Fang

2009-01-01

This study focuses on the observations of global atmospheric heat distributions using satellite measurements. Major heat components such as radiation energy, latent heat and sensible heat are considered. The uncertainties and error sources are assessed. Results show that the atmospheric heat is basically balanced, and the observed patterns of radiation and latent heat from precipitation are clearly related to general circulation.

Microfabricated thermoelectric power-generation devices

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre (Inventor); Phillips, Wayne (Inventor); Borshchevsky, Alex (Inventor); Kolawa, Elizabeth A. (Inventor); Ryan, Margaret A. (Inventor); Caillat, Thierry (Inventor); Mueller, Peter (Inventor); Snyder, G. Jeffrey (Inventor); Kascich, Thorsten (Inventor)

2002-01-01

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Microfabricated thermoelectric power-generation devices

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)

2004-01-01

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Thermal-Diode Sandwich Panel

NASA Technical Reports Server (NTRS)

Basiulis, A.

1986-01-01

Thermal diode sandwich panel transfers heat in one direction, but when heat load reversed, switches off and acts as thermal insulator. Proposed to control temperature in spacecraft and in supersonic missiles to protect internal electronics. In combination with conventional heat pipes, used in solar panels and other heat-sensitive systems.

Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System

PubMed Central

Panek, Jacek; Frąc, Magdalena; Bilińska-Wielgus, Nina

2016-01-01

Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700), the other from thermal processed strawberry product in 2012 (KC179765), used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I) acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods. PMID:26815302

Calibration, Data Acquisition, and Post Analysis of Turbulent Fluid Flow in a Calibration Jet Using Hot-wire Anemometry

NASA Technical Reports Server (NTRS)

Moreno, Michelle

2004-01-01

The Turbine Branch concentrates on the following areas: Computational Fluid Dynamics (CFD), and implementing experimental procedures to obtain physical modeling data. Hot-wire Anemometry is a valuable tool for obtaining physical modeling data. Hot-wire Anemometry is likely to remain the principal research tool for most turbulent air/gas flow studies. The Hot-wire anemometer consists of a fine wire heated by electric current. When placed in a fluid stream, the hot-wire loses heat to the fluid by forced convection. In forced convection, energy transfer is due to molecular motion imposed by an extraneous force moving fluid parcels. When the hot-wire is in "equilibrium", the rate of heat input to the wire is equal to the rate of heat loss at the wire ends. The equality between heat input and heat loss is the basis for King s equation, which relates the electrical parameters of the hot-wire to the flow parameters of the fluid. Hot-wire anemometry is based on convective heat transfer from a heated wire element placed in a fluid flow. Any change in the fluid flow condition that affects the heat transfer from the heated element will be detected virtually instantaneously by a constant-temperature Hot-wire anemometry system. The system implemented for this research is the IFA 300. The system is a fully-integrated, thermal anemometer-based system that measures mean and fluctuating velocity components in air, water, and other fluids. It also measures turbulence and makes localized temperature measurements. A constant-temperature anemometer is a bridge and amplifier circuit that controls a tiny wire at constant temperature. As a fluid flow passes over the heated sensor, the amplifier senses the bridge off-balance and adjusts the voltage to the top of the bridge, keeping the bridge in balance. The voltage on top of the bridge can then be related to the velocity of the flow. The bridge voltage is sensitive to temperature as well as velocity and so the built-in thermocouple circuit can be attached to a thermocouple that can measure the fluid temperature. Additional information is included in the original extended abstract.

Prototype solar heating and combined heating and cooling systems

NASA Technical Reports Server (NTRS)

1977-01-01

System analysis activities were directed toward refining the heating system parameters. Trade studies were performed to support hardware selections for all systems and for the heating only operational test sites in particular. The heating system qualification tests were supported by predicting qualification test component performance prior to conducting the test.

Rotary magnetic heat pump

DOEpatents

Kirol, Lance D.

1988-01-01

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

Rotary magnetic heat pump

DOEpatents

Kirol, L.D.

1987-02-11

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

Handbook of experiences in the design and installation of solar heating and cooling systems

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

Ward, D.S.; Oberoi, H.S.

1980-07-01

A large array of problems encountered are detailed, including design errors, installation mistakes, cases of inadequate durability of materials and unacceptable reliability of components, and wide variations in the performance and operation of different solar systems. Durability, reliability, and design problems are reviewed for solar collector subsystems, heat transfer fluids, thermal storage, passive solar components, piping/ducting, and reliability/operational problems. The following performance topics are covered: criteria for design and performance analysis, domestic hot water systems, passive space heating systems, active space heating systems, space cooling systems, analysis of systems performance, and performance evaluations. (MHR)

Investigating and understanding fouling in a planar setup using ultrasonic methods.

PubMed

Wallhäusser, E; Hussein, M A; Becker, T

2012-09-01

Fouling is an unwanted deposit on heat transfer surfaces and occurs regularly in foodstuff heat exchangers. Fouling causes high costs because cleaning of heat exchangers has to be carried out and cleaning success cannot easily be monitored. Thus, used cleaning cycles in foodstuff industry are usually too long leading to high costs. In this paper, a setup is described with which it is possible, first, to produce dairy protein fouling similar to the one found in industrial heat exchangers and, second, to detect the presence and absence of such fouling using an ultrasonic based measuring method. The developed setup resembles a planar heat exchanger in which fouling can be made and cleaned reproducible. Fouling presence, absence, and cleaning progress can be monitored by using an ultrasonic detection unit. The setup is described theoretically based on electrical and mechanical lumped circuits to derive the wave equation and the transfer function to perform a sensitivity analysis. Sensitivity analysis was done to determine influencing quantities and showed that fouling is measurable. Also, first experimental results are compared with results from sensitivity analysis.

Electronic and Interfacial Properties of PD/6H-SiC Schottky Diode Gas Sensors

NASA Technical Reports Server (NTRS)

Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.; Bansal, Gaurav; Petit, Jeremy B.; Knight, Dak; Liu, Chung-Chiun; Wu, Qinghai

1996-01-01

Pd/SiC Schottky diodes detect hydrogen and hydrocarbons with high sensitivity. Variation of the diode temperature from 100 C to 200 C shows that the diode sensitivity to propylene is temperature dependent. Long-term heat treating at 425 C up to 140 hours is carried out to determine the effect of extended heat treating on the diode properties and gas sensitivity. The heat treating significantly affects the diode's capacitive characteristics, but the diode's current carrying characteristics are much more stable with a large response to hydrogen. Scanning Electron Microscopy and X-ray Spectrometry studies of the Pd surface after the heating show cluster formation and background regions with grain structure observed in both regions. The Pd and Si concentrations vary between grains. Auger Electron Spectroscopy depth profiles revealed that the heat treating promoted interdiffusion and reaction between the Pd and SiC dw broadened the interface region. This work shows that Pd/SiC Schottky diodes have significant potential as high temperature gas sensors, but stabilization of the structure is necessary to insure their repeatability in long-term, high temperature applications.

Fabricating cooled electronic system with liquid-cooled cold plate and thermal spreader

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

Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.

Methods are provided for facilitating cooling of an electronic component. The method includes providing a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to bemore » cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less

Fabricating cooled electronic system with liquid-cooled cold plate and thermal spreader

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

Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.

Methods are provided for facilitating cooling of an electronic component. The methods include providing a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to bemore » cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less

Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing.

PubMed

Ding, Donghong; Pan, Zengxi; van Duin, Stephen; Li, Huijun; Shen, Chen

2016-08-03

Cast nickel aluminum bronze (NAB) alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM). Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT) are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production.

Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing

PubMed Central

Ding, Donghong; Pan, Zengxi; van Duin, Stephen; Li, Huijun; Shen, Chen

2016-01-01

Cast nickel aluminum bronze (NAB) alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM). Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT) are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production. PMID:28773774

System implications of aperture-shade design for the SIRTF Observatory

NASA Technical Reports Server (NTRS)

Lee, J. H.; Brooks, W. F.; Maa, S.

1987-01-01

The 1-m-aperture Space Infrared Telescope Facility (SIRTF) will operate with a sensitivity limited only by the zodiacal background. This sensitivity requirement places severe restrictions on the amount of stray light which can reach the focal plane from off-axis sources such as the sun or earth limb. In addition, radiation from these sources can degrade the lifetime of the telescope and instrument cryogenic system which is now planned for two years before the first servicing. Since the aperture of the telescope represents a break in the telescope insulation system and is effectively the first element in the optical train, the aperture shade is a key system component. The mass, length, and temperature of the shade should be minimized to reduce system cost while maximizing the telescope lifetime and stray light performance. The independent geometric parameters that characterize an asymmetrical shade for a 600 km, 28 deg orbit were identified, and the system sensitivity to the three most important shade parameters were explored. Despite the higher heat loads compared to previously studied polar orbit missions, the analysis determined that passive radiators of a reasonable size are sufficient to meet the system requirements. An optimized design for the SIRTF mission, based on the sensitivity analysis, is proposed.

Temperature-sensitive mutants of measles virus produced from persistently infected HeLa cells.

PubMed

Armen, R C; Evermann, J F; Truant, A L; Laughlin, C A; Hallum, J V

1977-01-01

A persistent infection with the Edmonston strain of measles virus was established in HeLa cells in the absence of measles virus antibody (HeLaPI cells). By hemadsorption or immunofluoresnce virtually 100 per cent of the cells possessed measles virus components. HeLaPI cells produced no interferon and were not resistant to superinfection with Newcastle disease virus. HeLaPI cells contained both smooth (15--18 nm) and rought (20--35 nm) nucleocapsids as detected by electron microscopy. The virus produced from the HeLaPI cells (MVPI) varied in titer between 1.5 X 10(2) and 5.5 X10(4) PFU/ml, had a smaller plque size and was more heat resistant than wild-type measles virus. MVPI was also found to be temperature-sensitive. The temperature-sensitivity of MVPI was determined by the efficiency of plaquing at 33 degrees and 39 degrees C in Vero cell monolayers. When HeLaPI cells were incubated at 33 degrees C, there was a 50-fold increase in virus production as well as a slight increase in the percentage of cells forming infectious centers compared to HeLaPI cells grown at 37 degrees C. MVPI readily established a persistent infection in HeLa cells which also rleased temperature-sensitive virus.

A model of heat flow in the sheep exposed to high levels of solar radiation.

PubMed

Vera, R R; Koong, L J; Morris, J G

1975-08-01

The fleece is an important component in thermoregulation of sheep exposed to high levels of solar radiation. A model written in CSMP has been developed which represents the flow of energy between the sheep and its environment. This model is based on a set of differential equations which describe the flux of heat between the components of the system--fleece, tip, skin, body and environment. It requires as input parameters location, date, time of day, temperature, relative humidity, cloud cover, wind movement, animal weight and linear measurements and fleece length. At each integration interval incoming solar radiation and its components, the heat arising from the animal's metabolism and the heat exchange by long-wave radiation, convection, conduction and evaporative cooling are computed. Temperatures at the fleece tip, skin and body core are monitored.

Advances in the Breeding and Genetics of Heat Tolerance to Alleviate the Effects of Climate Change, with a Focus on Common Bean

USDA-ARS?s Scientific Manuscript database

Crop plants are broadly sensitive to high ambient temperatures during reproductive development while breeding efforts are helping to alleviate the impact of heat stress. Common bean, Phaseolus vulgaris L., is sensitive to moderately high ambient temperature, where temperatures greater than 25C have ...

Estimating heat capacity and heat content of rocks

USGS Publications Warehouse

Robertson, Eugene C.; Hemingway, Bruch S.

1995-01-01

Our measured heat-capacity values for rocks and other measurements of heat capacity or heat content of rocks found in the literature have been compared with estimated rock heat capacities calculated from the summation of heat capacities of both minerals and oxide components. The validity of calculating the heat content or heat capacity of rocks to better than about ± 3% from its mineral or chemical composition is well demonstrated by the data presented here.

Development of a Conceptual Structure for Architectural Solar Energy Systems.

ERIC Educational Resources Information Center

Ringel, Robert F.

Solar subsystems and components were identified and conceptual structure was developed for architectural solar energy heating and cooling systems. Recent literature related to solar energy systems was reviewed and analyzed. Solar heating and cooling system, subsystem, and component data were compared for agreement and completeness. Significant…

Thermal conductive heating in fractured bedrock: Screening calculations to assess the effect of groundwater influx

NASA Astrophysics Data System (ADS)

Baston, Daniel P.; Kueper, Bernard H.

2009-02-01

A two-dimensional semi-analytical heat transfer solution is developed and a parameter sensitivity analysis performed to determine the relative importance of rock material properties (density, thermal conductivity and heat capacity) and hydrogeological properties (hydraulic gradient, fracture aperture, fracture spacing) on the ability to heat fractured rock using thermal conductive heating (TCH). The solution is developed using a Green's function approach in which an integral equation is constructed for the temperature in the fracture. Subsurface temperature distributions are far more sensitive to hydrogeological properties than material properties. The bulk ground water influx ( q) can provide a good estimate of the extent of influx cooling when influx is low to moderate, allowing the prediction of temperatures during heating without specific knowledge of the aperture and spacing of fractures. Target temperatures may not be reached or may be significantly delayed when the groundwater influx is large.

Dissolution and subsequent re-crystallization as zeroing mechanism, thermal properties and component resolved dose response of salt (NaCl) for retrospective dosimetry.

PubMed

Polymeris, George S; Kitis, George; Kiyak, Nafiye G; Sfamba, Ioanna; Subedi, Bhagawan; Pagonis, Vasilis

2011-09-01

In the present study we report dosimetric properties of iodized salt aiming at using it as an accidental luminescent dosimeter. It was found that the very good sensitivity of its main dosimetric peak is strongly affected by thermal treatments. This is also the case for OSL emission. The sensitivity loss due to heating implies that caution should be exercised while applying single aliquot protocols for dose evaluation. The sequence of dissolution and subsequent re-crystallization was established to be an extremely effective zeroing mechanism for the TL signal. The linearity in the dose response was also monitored in the case of dissolved and subsequently re-crystallized salt. In the case of naturally occurring salt, zeroing of the TL signal due to dissolution as well as the linearity of dose response up to doses as large as 100 Gy were found to be very promising features for dating applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Design and optimisation of low heat load liquid helium cryostat to house cryogenic current comparator in antiproton decelerator at CERN

NASA Astrophysics Data System (ADS)

Lees, A.; Koettig, T.; Fernandes, M.; Tan, J.

2017-02-01

The Cryogenic Current Comparator (CCC) is installed in the low-energy Antiproton Decelerator (AD) at CERN to make an absolute measurement of the beam intensity. Operating below 4.2 K, it is based on a superconducting quantum interference device (SQUID) and employs a superconducting niobium shield to supress magnetic field components not linked to the beam current. The AD contains no permanent cryogenic infrastructure so the local continuous liquefaction of helium using a pulse-tube is required; limiting the available cooling power to 0.69 W at 4.2K. Due to the sensitivity of the SQUID to variations in magnetic fields, the CCC is highly sensitive to mechanical vibration which is limited to a minimum by the support systems of the cryostat. This article presents the cooling system of the cryostat and discusses the design challenges overcome to minimise the transmission of vibration to the CCC while operating within the cryogenic limits imposed by the cooling system.

The heat removal capability of actively cooled plasma-facing components for the ITER divertor

NASA Astrophysics Data System (ADS)

Missirlian, M.; Richou, M.; Riccardi, B.; Gavila, P.; Loarer, T.; Constans, S.

2011-12-01

Non-destructive examination followed by high-heat-flux testing was performed for different small- and medium-scale mock-ups; this included the most recent developments related to actively cooled tungsten (W) or carbon fibre composite (CFC) armoured plasma-facing components. In particular, the heat-removal capability of these mock-ups manufactured by European companies with all the main features of the ITER divertor design was investigated both after manufacturing and after thermal cycling up to 20 MW m-2. Compliance with ITER requirements was explored in terms of bonding quality, heat flux performances and operational compatibility. The main results show an overall good heat-removal capability after the manufacturing process independent of the armour-to-heat sink bonding technology and promising behaviour with respect to thermal fatigue lifetime under heat flux up to 20 MW m-2 for the CFC-armoured tiles and 15 MW m-2 for the W-armoured tiles, respectively.

Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

NASA Technical Reports Server (NTRS)

1997-01-01

This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the Goddard Institute for Space Studies (GISS) 8 deg x lO deg atmospheric General Circulation Model (GCM) to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

NASA Technical Reports Server (NTRS)

1998-01-01

This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the GISS 8 deg x lO deg atmospheric GCM to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

Relationships between drought, heat and air humidity responses revealed by transcriptome-metabolome co-analysis.

PubMed

Georgii, Elisabeth; Jin, Ming; Zhao, Jin; Kanawati, Basem; Schmitt-Kopplin, Philippe; Albert, Andreas; Winkler, J Barbro; Schäffner, Anton R

2017-07-10

Elevated temperature and reduced water availability are frequently linked abiotic stresses that may provoke distinct as well as interacting molecular responses. Based on non-targeted metabolomic and transcriptomic measurements from Arabidopsis rosettes, this study aims at a systematic elucidation of relevant components in different drought and heat scenarios as well as relationships between molecular players of stress response. In combined drought-heat stress, the majority of single stress responses are maintained. However, interaction effects between drought and heat can be discovered as well; these relate to protein folding, flavonoid biosynthesis and growth inhibition, which are enhanced, reduced or specifically induced in combined stress, respectively. Heat stress experiments with and without supplementation of air humidity for maintenance of vapor pressure deficit suggest that decreased relative air humidity due to elevated temperature is an important component of heat stress, specifically being responsible for hormone-related responses to water deprivation. Remarkably, this "dry air effect" is the primary trigger of the metabolomic response to heat. In contrast, the transcriptomic response has a substantial temperature component exceeding the dry air component and including up-regulation of many transcription factors and protein folding-related genes. Data level integration independent of prior knowledge on pathways and condition labels reveals shared drought and heat responses between transcriptome and metabolome, biomarker candidates and co-regulation between genes and metabolic compounds, suggesting novel players in abiotic stress response pathways. Drought and heat stress interact both at transcript and at metabolite response level. A comprehensive, non-targeted view of this interaction as well as non-interacting processes is important to be taken into account when improving tolerance to abiotic stresses in breeding programs. Transcriptome and metabolome may respond with different extent to individual stress components. Their contrasting behavior in response to temperature stress highlights that the protein folding machinery effectively shields the metabolism from stress. Disentangling the complex relationships between transcriptome and metabolome in response to stress is an enormous challenge. As demonstrated by case studies with supporting evidence from additional data, the large dataset provided in this study may assist in determining linked genetic and metabolic features as candidates for future mechanistic analyses.

Characteristics of the Surface Turbulent Flux and the Components of Radiation Balance over the Grasslands in the Southeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Li, H.; Xiao, Z.; Wei, J.

2016-12-01

Characteristics of the Surface Turbulent Flux and the Components of Radiation Balance over the Grasslands in the Southeastern Tibetan PlateauHongyi Li 1, Ziniu Xiao 2 and Junhong Wei31 China Meteorological Administration Training Centre, Beijing, China2 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China 3Theory of Atmospheric Dynamics and Climate, Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt, Campus Riedberg, GermanyAbstract:Based on the field observation data over the grasslands in the southeastern Tibetan Plateau and the observational datasets in Nyingchi weather station for the period from May 20 to July 9, 2013, the variation characteristics of the basic meteorological elements in Nyingchi weather station, the surface turbulent fluxes and the components of radiation balance over the grasslands, as well as their relationships, are analyzed in this paper. The results show that in Nyingchi weather station, the daily variations of relative humidity and average total cloud cover are consistent with that of precipitation, but that those of daily average air temperature, daily average ground temperature, daily average wind speed and daily sunshine duration have an opposite change to that of precipitation. During the observation period, latent heat exchange is greater than sensible heat exchange, and latent heat flux is significantly higher when there is rainfall, but sensible heat flux and soil heat flux are lower. The daily variation of the total solar radiation (DR) is synchronous with that of sensible heat flux, and the daily variations of reflective solar radiation (UR), long wave radiation by earth (ULR), net radiation (Rn) and surface albedo are consistent with DR, but that of the long wave radiation by atmosphere (DLR) has an opposite change. The diurnal variations of sensible heat flux, latent heat flux, soil heat flux and the components of surface radiation balance over the grasslands are characterized by higher values at noon and lower values in the morning and evening. Keywords: surface turbulent flux, components of radiation balance, grasslands, southeastern Tibetan Plateau

Acute heat tolerance of cardiac excitation in the brown trout (Salmo trutta fario).

PubMed

Vornanen, Matti; Haverinen, Jaakko; Egginton, Stuart

2014-01-15

The upper thermal tolerance and mechanisms of heat-induced cardiac failure in the brown trout (Salmo trutta fario) was examined. The point above which ion channel function and sinoatrial contractility in vitro, and electrocardiogram (ECG) in vivo, started to fail (break point temperature, BPT) was determined by acute temperature increases. In general, electrical excitation of the heart was most sensitive to heat in the intact animal (electrocardiogram, ECG) and least sensitive in isolated cardiac myocytes (ion currents). BPTs of Ca(2+) and K(+) currents of cardiac myocytes were much higher (>28°C) than BPT of in vivo heart rate (23.5 ± 0.6°C) (P<0.05). A striking exception among sarcolemmal ion conductances was the Na(+) current (INa), which was the most heat-sensitive molecular function, with a BPT of 20.9 ± 0.5°C. The low heat tolerance of INa was reflected as a low BPT for the rate of action potential upstroke in vitro (21.7 ± 1.2°C) and the velocity of impulse transmission in vivo (21.9 ± 2.2°C). These findings from different levels of biological organization strongly suggest that heat-dependent deterioration of Na(+) channel function disturbs normal spread of electrical excitation over the heart, leading to progressive variability of cardiac rhythmicity (missed beats, bursts of fast beating), reduction of heart rate and finally cessation of the normal heartbeat. Among the cardiac ion currents INa is 'the weakest link' and possibly a limiting factor for upper thermal tolerance of electrical excitation in the brown trout heart. Heat sensitivity of INa may result from functional requirements for very high flux rates and fast gating kinetics of the Na(+) channels, i.e. a trade-off between high catalytic activity and thermal stability.

Base Heating Sensitivity Study for a 4-Cluster Rocket Motor Configuration in Supersonic Freestream

NASA Technical Reports Server (NTRS)

Mehta, Manish; Canabal, Francisco; Tashakkor, Scott B.; Smith, Sheldon D.

2011-01-01

In support of launch vehicle base heating and pressure prediction efforts using the Loci-CHEM Navier-Stokes computational fluid dynamics solver, 35 numerical simulations of the NASA TND-1093 wind tunnel test have been modeled and analyzed. This test article is composed of four JP-4/LOX 500 lbf rocket motors exhausting into a Mach 2 - 3.5 wind tunnel at various ambient pressure conditions. These water-cooled motors are attached to a base plate of a standard missile forebody. We explore the base heating profiles for fully coupled finite-rate chemistry simulations, one-way coupled RAMP (Reacting And Multiphase Program using Method of Characteristics)-BLIMPJ (Boundary Layer Integral Matrix Program - Jet Version) derived solutions and variable and constant specific heat ratio frozen flow simulations. Variations in turbulence models, temperature boundary conditions and thermodynamic properties of the plume have been investigated at two ambient pressure conditions: 255 lb/sq ft (simulated low altitude) and 35 lb/sq ft (simulated high altitude). It is observed that the convective base heat flux and base temperature are most sensitive to the nozzle inner wall thermal boundary layer profile which is dependent on the wall temperature, boundary layer s specific energy and chemical reactions. Recovery shock dynamics and afterburning significantly influences convective base heating. Turbulence models and external nozzle wall thermal boundary layer profiles show less sensitivity to base heating characteristics. Base heating rates are validated for the highest fidelity solutions which show an agreement within +/-10% with respect to test data.

Sensitivity of boundary layer variables to PBL schemes over the central Tibetan Plateau

NASA Astrophysics Data System (ADS)

Xu, L.; Liu, H.; Wang, L.; Du, Q.; Liu, Y.

2017-12-01

Planetary Boundary Layer (PBL) parameterization schemes play critical role in numerical weather prediction and research. They describe physical processes associated with the momentum, heat and humidity exchange between land surface and atmosphere. In this study, two non-local (YSU and ACM2) and two local (MYJ and BouLac) planetary boundary layer parameterization schemes in the Weather Research and Forecasting (WRF) model have been tested over the central Tibetan Plateau regarding of their capability to model boundary layer parameters relevant for surface energy exchange. The model performance has been evaluated against measurements from the Third Tibetan Plateau atmospheric scientific experiment (TIPEX-III). Simulated meteorological parameters and turbulence fluxes have been compared with observations through standard statistical measures. Model results show acceptable behavior, but no particular scheme produces best performance for all locations and parameters. All PBL schemes underestimate near surface air temperatures over the Tibetan Plateau. By investigating the surface energy budget components, the results suggest that downward longwave radiation and sensible heat flux are the main factors causing the lower near surface temperature. Because the downward longwave radiation and sensible heat flux are respectively affected by atmosphere moisture and land-atmosphere coupling, improvements in water vapor distribution and land-atmosphere energy exchange is meaningful for better presentation of PBL physical processes over the central Tibetan Plateau.

Attributing anthropogenic impact on regional heat wave events using CAM5 model large ensemble simulations

NASA Astrophysics Data System (ADS)

Lo, S. H.; Chen, C. T.

2017-12-01

Extreme heat waves have serious impacts on society. It was argued that the anthropogenic forcing might substantially increase the risk of extreme heat wave events (e.g. over western Europe in 2003 and over Russia in 2010). However, the regional dependence of such anthropogenic impact and the sensitivity of the attributed risk to the definition of heat wave still require further studies. In our research framework, the change in the frequency and severity of a heat wave event under current conditions is calculated and compared with the probability and magnitude of the event if the effects of particular external forcing, such as due to human influence, had been absent. In our research, we use the CAM5 large ensemble simulation from the CLIVAR C20C+ Detection and Attribution project (http://portal.nersc.gov/c20c/main.html, Folland et al. 2014) to detect the heat wave events occurred in both historical all forcing run and natural forcing only run. The heat wave events are identified by partial duration series method (Huth et al., 2000). We test the sensitivity of heat wave thresholds from daily maximum temperature (Tmax) in warm season (from May to September) between 1959 and 2013. We consider the anthropogenic effect on the later period (2000-2013) when the warming due to human impact is more evident. Using Taiwan and surrounding area as our preliminary research target, We found the anthropogenic effect will increase the heat wave day per year from 30 days to 75 days and make the mean starting(ending) day for heat waves events about 15-30 days earlier(later). Using the Fraction of Attribution Risk analysis to estimate the risk of frequency of heat wave day, our results show the anthropogenic forcing very likely increase the heat wave days over Taiwan by more than 50%. Further regional differences and sensitivity of the attributed risk to the definition of heat wave will be compared and discussed.

A fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot cavity

NASA Astrophysics Data System (ADS)

Liu, Guigen; Sheng, Qiwen; Resende Lisboa Piassetta, Geraldo; Hou, Weilin; Han, Ming

2016-05-01

A hot-wire fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot interferometer (FPI) has been proposed and demonstrated in this paper. The operation of the sensor is based on the convective heat loss to water from a heated silicon FPI attached to the cleaved enface of a piece of single-mode fiber. The flow-induced change in the temperature is demodulated by the spectral shifts of the reflection fringes. An analytical model based on the FPI theory and heat transfer analysis has been developed for performance analysis. Numerical simulations based on finite element analysis have been conducted. The analytical and numerical results agree with each other in predicting the behavior of the sensor. Experiments have also been carried to demonstrate the sensing principle and verify the theoretical analysis. Investigations suggest that the sensitivity at low flow rates are much larger than that at high flow rates and the sensitivity can be easily improved by increasing the heating laser power. Experimental results show that an average sensitivity of 52.4 nm/(m/s) for the flow speed range of 1.5 mm/s to 12 mm/s was obtained with a heating power of ~12 mW, suggesting a resolution of ~1 μm/s assuming a wavelength resolution of 0.05 pm.

Somatosensory nociceptive characteristics differentiate subgroups in people with chronic low back pain: a cluster analysis.

PubMed

Rabey, Martin; Slater, Helen; OʼSullivan, Peter; Beales, Darren; Smith, Anne

2015-10-01

The objectives of this study were to explore the existence of subgroups in a cohort with chronic low back pain (n = 294) based on the results of multimodal sensory testing and profile subgroups on demographic, psychological, lifestyle, and general health factors. Bedside (2-point discrimination, brush, vibration and pinprick perception, temporal summation on repeated monofilament stimulation) and laboratory (mechanical detection threshold, pressure, heat and cold pain thresholds, conditioned pain modulation) sensory testing were examined at wrist and lumbar sites. Data were entered into principal component analysis, and 5 component scores were entered into latent class analysis. Three clusters, with different sensory characteristics, were derived. Cluster 1 (31.9%) was characterised by average to high temperature and pressure pain sensitivity. Cluster 2 (52.0%) was characterised by average to high pressure pain sensitivity. Cluster 3 (16.0%) was characterised by low temperature and pressure pain sensitivity. Temporal summation occurred significantly more frequently in cluster 1. Subgroups were profiled on pain intensity, disability, depression, anxiety, stress, life events, fear avoidance, catastrophizing, perception of the low back region, comorbidities, body mass index, multiple pain sites, sleep, and activity levels. Clusters 1 and 2 had a significantly greater proportion of female participants and higher depression and sleep disturbance scores than cluster 3. The proportion of participants undertaking <300 minutes per week of moderate activity was significantly greater in cluster 1 than in clusters 2 and 3. Low back pain, therefore, does not appear to be homogeneous. Pain mechanisms relating to presentations of each subgroup were postulated. Future research may investigate prognoses and interventions tailored towards these subgroups.

RELAP5-3D Modeling of Heat Transfer Components (Intermediate Heat Exchanger and Helical-Coil Steam Generator) for NGNP Application

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

N. A. Anderson; P. Sabharwall

2014-01-01

The Next Generation Nuclear Plant project is aimed at the research and development of a helium-cooled high-temperature gas reactor that could generate both electricity and process heat for the production of hydrogen. The heat from the high-temperature primary loop must be transferred via an intermediate heat exchanger to a secondary loop. Using RELAP5-3D, a model was developed for two of the heat exchanger options a printed-circuit heat exchanger and a helical-coil steam generator. The RELAP5-3D models were used to simulate an exponential decrease in pressure over a 20 second period. The results of this loss of coolant analysis indicate thatmore » heat is initially transferred from the primary loop to the secondary loop, but after the decrease in pressure in the primary loop the heat is transferred from the secondary loop to the primary loop. A high-temperature gas reactor model should be developed and connected to the heat transfer component to simulate other transients.« less

Compositional effects on the ignition of FACE gasolines [Compositional effects on the ignition of FACE gasoline fuels: experiments, surrogate fuel formulation, and chemical kinetic modeling

DOE PAGES

Sarathy, S. Mani; Kukkadapu, Goutham; Mehl, Marco; ...

2016-05-08

As regulatory measures for improved fuel economy and decreased emissions are pushing gasoline engine combustion technologies towards extreme conditions (i.e., boosted and intercooled intake with exhaust gas recirculation), fuel ignition characteristics become increasingly important for enabling stable operation. Here, this study explores the effects of chemical composition on the fundamental ignition behavior of gasoline fuels. Two well-characterized, high-octane, non-oxygenated FACE (Fuels for Advanced Combustion Engines) gasolines, FACE F and FACE G, having similar antiknock indices but different octane sensitivities and chemical compositions are studied. Ignition experiments were conducted in shock tubes and a rapid compression machine (RCM) at nominal pressuresmore » of 20 and 40 atm, equivalence ratios of 0.5 and 1.0, and temperatures ranging from 650 to 1270 K. Results at temperatures above 900 K indicate that ignition delay time is similar for these fuels. However, RCM measurements below 900 K demonstrate a stronger negative temperature coefficient behavior for FACE F gasoline having lower octane sensitivity. In addition, RCM pressure profiles under two-stage ignition conditions illustrate that the magnitude of low-temperature heat release (LTHR) increases with decreasing fuel octane sensitivity. However, intermediate-temperature heat release is shown to increase as fuel octane sensitivity increases. Various surrogate fuel mixtures were formulated to conduct chemical kinetic modeling, and complex multicomponent surrogate mixtures were shown to reproduce experimentally observed trends better than simpler two- and three-component mixtures composed of n-heptane, iso-octane, and toluene. Measurements in a Cooperative Fuels Research (CFR) engine demonstrated that the multicomponent surrogates accurately captured the antiknock quality of the FACE gasolines. Simulations were performed using multicomponent surrogates for FACE F and G to reveal the underlying chemical kinetics linking fuel composition with ignition characteristics. Finally, a key discovery of this work is the kinetic coupling between aromatics and naphthenes, which affects the radical pool population and thereby controls ignition.« less

Compositional effects on the ignition of FACE gasolines [Compositional effects on the ignition of FACE gasoline fuels: experiments, surrogate fuel formulation, and chemical kinetic modeling

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

Sarathy, S. Mani; Kukkadapu, Goutham; Mehl, Marco

As regulatory measures for improved fuel economy and decreased emissions are pushing gasoline engine combustion technologies towards extreme conditions (i.e., boosted and intercooled intake with exhaust gas recirculation), fuel ignition characteristics become increasingly important for enabling stable operation. Here, this study explores the effects of chemical composition on the fundamental ignition behavior of gasoline fuels. Two well-characterized, high-octane, non-oxygenated FACE (Fuels for Advanced Combustion Engines) gasolines, FACE F and FACE G, having similar antiknock indices but different octane sensitivities and chemical compositions are studied. Ignition experiments were conducted in shock tubes and a rapid compression machine (RCM) at nominal pressuresmore » of 20 and 40 atm, equivalence ratios of 0.5 and 1.0, and temperatures ranging from 650 to 1270 K. Results at temperatures above 900 K indicate that ignition delay time is similar for these fuels. However, RCM measurements below 900 K demonstrate a stronger negative temperature coefficient behavior for FACE F gasoline having lower octane sensitivity. In addition, RCM pressure profiles under two-stage ignition conditions illustrate that the magnitude of low-temperature heat release (LTHR) increases with decreasing fuel octane sensitivity. However, intermediate-temperature heat release is shown to increase as fuel octane sensitivity increases. Various surrogate fuel mixtures were formulated to conduct chemical kinetic modeling, and complex multicomponent surrogate mixtures were shown to reproduce experimentally observed trends better than simpler two- and three-component mixtures composed of n-heptane, iso-octane, and toluene. Measurements in a Cooperative Fuels Research (CFR) engine demonstrated that the multicomponent surrogates accurately captured the antiknock quality of the FACE gasolines. Simulations were performed using multicomponent surrogates for FACE F and G to reveal the underlying chemical kinetics linking fuel composition with ignition characteristics. Finally, a key discovery of this work is the kinetic coupling between aromatics and naphthenes, which affects the radical pool population and thereby controls ignition.« less

Re-examination of the Neisser—Wechsberg (antibody prozone) phenomenon

PubMed Central

Muschel, L. H.; Gustafson, Linda; Larsen, Linda J.

1969-01-01

Although the Neisser—Wechsberg phenomenon resembles the inhibition of agglutination systems by excess antibody, the experimental results have indicated that with heat-inactivated antiserum the phenomenon results both from an excess of specific antibody and of non-specific anti-complementary activity. Complement (C) has been shown to be fixed in the presence of the excess antiserum which inhibits the bactericidal reaction. The inhibition was overcome by an excess of the third complement component factors indicating that the excess of antiserum interfered with the activation or function of the components acting at one of the late steps in the reaction sequence. The prozone phenomenon was relatively slight when unheated antiserum was used or when sensitized organisms were washed to remove serum substances unrelated to antibody. Non-specific anti-complementary activity, therefore, is a major contributor to the prozone phenomenon. Both IgM and IgG fractions of rabbit antisera elicited a prozone although the former had relatively greater bactericidal than inhibitory activity. PMID:5352361

Selective detection of cavitation bubbles by triplet pulse sequence in high-intensity focused ultrasound treatment

NASA Astrophysics Data System (ADS)

Iwasaki, Ryosuke; Nagaoka, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

2018-07-01

Acoustic cavitation bubbles are known to enhance the heating effect in high-intensity focused ultrasound (HIFU) treatment. The detection of cavitation bubbles with high sensitivity and selectivity is required to predict the therapeutic and side effects of cavitation, and ensure the efficacy and safety of the treatment. A pulse inversion (PI) technique has been widely used for imaging microbubbles through enhancing the second-harmonic component of echo signals. However, it has difficulty in separating the nonlinear response of microbubbles from that due to nonlinear propagation. In this study, a triplet pulse (3P) method was investigated to specifically image cavitation bubbles by extracting the 1.5th fractional harmonic component. The proposed 3P method depicted cavitation bubbles with a contrast ratio significantly higher than those in conventional imaging methods with and without PI. The results suggest that the 3P method is effective for specifically detecting microbubbles in cavitation-enhanced HIFU treatment.

Modeling the microstructural changes during hot tandem rolling of AA5 XXX aluminum alloys: Part II. Textural evolution

NASA Astrophysics Data System (ADS)

Wells, M. A.; Samarasekera, I. V.; Brimacombe, J. K.; Hawbolt, E. B.; Lloyd, D. J.

1998-06-01

In Part II of this article, the experimental work undertaken to measure the effect of deformation parameters (temperature, strain, and strain rate) on the texture formation during hot deformation and the evolution during subsequent recrystallization is described. In addition, the isothermal kinetics of development of individual texture components were also determined. A neutron diffractometer was used to measure the texture in the as-hot-deformed aluminum samples, and the samples were then heat treated in a 400 °C salt bath for various lengths of time, with the texture being remeasured at various stages in the recrystallization process. Using data from the experimental program, the texture evolution during recrystallization was modeled by applying a modified form of the Avrami equation. Results indicated that, of the deformation parameters studied, textural development was most sensitive to the deformation temperature for both alloys. In addition, modeling results revealed that the Cu component ({112} <111>) was the first to recrystallize, typically followed by the S ({123} <634>) and Bs ({110} <112>) components. This is in agreement with earlier work which indicated that the Bs component was the hardest to recrystallize, possibly because it is able to deform on very few slip systems and, hence, the dislocation interaction may be low.

Experimental evaluation of cooling efficiency of the high performance cooling device

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan

2016-06-01

This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

Heat-flow equation motivated by the ideal-gas shock wave.

PubMed

Holian, Brad Lee; Mareschal, Michel

2010-08-01

We present an equation for the heat-flux vector that goes beyond Fourier's Law of heat conduction, in order to model shockwave propagation in gases. Our approach is motivated by the observation of a disequilibrium among the three components of temperature, namely, the difference between the temperature component in the direction of a planar shock wave, versus those in the transverse directions. This difference is most prominent near the shock front. We test our heat-flow equation for the case of strong shock waves in the ideal gas, which has been studied in the past and compared to Navier-Stokes solutions. The new heat-flow treatment improves the agreement with nonequilibrium molecular-dynamics simulations of hard spheres under strong shockwave conditions.

Sensitivity, specificity, and predictive values of pediatric metabolic syndrome components in relation to adult metabolic syndrome: the Princeton LRC follow-up study.

PubMed

Huang, Terry T-K; Nansel, Tonja R; Belsheim, Allen R; Morrison, John A

2008-02-01

To estimate the sensitivity, specificity, and predictive values of pediatric metabolic syndrome (MetS) components (obesity, fasting glucose, triglycerides, high-density lipoprotein, and blood pressure) at various cutoff points in relation to adult MetS. Data from the National Heart, Lung, and Blood Institute Lipid Research Clinics Princeton Prevalence Study (1973-1976) and the Princeton Follow-up Study (2000-2004) were used to calculate sensitivity, specificity, and positive and negative predictive values for each component at a given cutoff point and for aggregates of components. Individual pediatric components alone showed low to moderate sensitivity, high specificity, and moderate predictive values in relation to adult MetS. When all 5 pediatric MetS components were considered, the presence of at least 1 abnormality had higher sensitivity for adult MetS than individual components alone. When multiple abnormalities were mandatory for MetS, positive predictive value was high and sensitivity was low. Childhood body mass alone showed neither high sensitivity nor high positive predictive value for adult MetS. Considering multiple metabolic variables in childhood can improve the predictive usefulness for adult MetS, compared with each component or body mass alone. MetS variables may be useful for identifying some children who are at risk for prevention interventions.

Active heat exchange system development for latent heat thermal energy storage

NASA Technical Reports Server (NTRS)

Lefrois, R. T.; Mathur, A. K.

1980-01-01

Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

Active heat exchange system development for latent heat thermal energy storage

NASA Astrophysics Data System (ADS)

Lefrois, R. T.; Mathur, A. K.

1980-04-01

Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

(NESC) NASA Engineering and Safety Center Orion Heat Shield Carr

NASA Image and Video Library

2014-04-29

(NESC) NASA Engineering and Safety Center Orion Heat Shield Carrier Structure: Titanium Orthogrid heat shield sub-component dynamic test article : person in the photo Jim Jeans (Background: Mike Kirsch, James Ainsworth)

Deterministic Local Sensitivity Analysis of Augmented Systems - II: Applications to the QUENCH-04 Experiment Using the RELAP5/MOD3.2 Code System

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

Ionescu-Bujor, Mihaela; Jin Xuezhou; Cacuci, Dan G.

2005-09-15

The adjoint sensitivity analysis procedure for augmented systems for application to the RELAP5/MOD3.2 code system is illustrated. Specifically, the adjoint sensitivity model corresponding to the heat structure models in RELAP5/MOD3.2 is derived and subsequently augmented to the two-fluid adjoint sensitivity model (ASM-REL/TF). The end product, called ASM-REL/TFH, comprises the complete adjoint sensitivity model for the coupled fluid dynamics/heat structure packages of the large-scale simulation code RELAP5/MOD3.2. The ASM-REL/TFH model is validated by computing sensitivities to the initial conditions for various time-dependent temperatures in the test bundle of the Quench-04 reactor safety experiment. This experiment simulates the reflooding with water ofmore » uncovered, degraded fuel rods, clad with material (Zircaloy-4) that has the same composition and size as that used in typical pressurized water reactors. The most important response for the Quench-04 experiment is the time evolution of the cladding temperature of heated fuel rods. The ASM-REL/TFH model is subsequently used to perform an illustrative sensitivity analysis of this and other time-dependent temperatures within the bundle. The results computed by using the augmented adjoint sensitivity system, ASM-REL/TFH, highlight the reliability, efficiency, and usefulness of the adjoint sensitivity analysis procedure for computing time-dependent sensitivities.« less

Circulating heat exchangers for oscillating wave engines and refrigerators

DOEpatents

Swift, Gregory W.; Backhaus, Scott N.

2003-10-28

An oscillating-wave engine or refrigerator having a regenerator or a stack in which oscillating flow of a working gas occurs in a direction defined by an axis of a trunk of the engine or refrigerator, incorporates an improved heat exchanger. First and second connections branch from the trunk at locations along the axis in selected proximity to one end of the regenerator or stack, where the trunk extends in two directions from the locations of the connections. A circulating heat exchanger loop is connected to the first and second connections. At least one fluidic diode within the circulating heat exchanger loop produces a superimposed steady flow component and oscillating flow component of the working gas within the circulating heat exchanger loop. A local process fluid is in thermal contact with an outside portion of the circulating heat exchanger loop.

Altered Pain Sensitivity in Elderly Women with Chronic Neck Pain

PubMed Central

Uthaikhup, Sureeporn; Prasert, Romchat; Paungmali, Aatit; Boontha, Kritsana

2015-01-01

Background Age-related changes occur in both the peripheral and central nervous system, yet little is known about the influence of chronic pain on pain sensitivity in older persons. The aim of this study was to investigate pain sensitivity in elders with chronic neck pain compared to healthy elders. Methods Thirty elderly women with chronic neck pain and 30 controls were recruited. Measures of pain sensitivity included pressure pain thresholds, heat/cold pain thresholds and suprathreshold heat pain responses. The pain measures were assessed over the cervical spine and at a remote site, the tibialis anterior muscle. Results Elders with chronic neck pain had lower pressure pain threshold over the articular pillar of C5-C6 and decreased cold pain thresholds over the cervical spine and tibialis anterior muscle when compared with controls (p < 0.05). There were no between group differences in heat pain thresholds and suprathreshold heat pain responses (p > 0.05). Conclusion The presence of pain hypersensitivity in elderly women with chronic neck pain appears to be dependent on types of painful stimuli. This may reflect changes in the peripheral and central nervous system with age. PMID:26039149

Sensitivity of bronchopulmonary receptors to cold and heat mediated by transient receptor potential cation channel subtypes in an ex vivo rat lung preparation.

PubMed

Zhou, Yun; Sun, Biying; Li, Qian; Luo, Pin; Dong, Li; Rong, Weifang

2011-08-15

Changes in airway temperature can result in respiratory responses such as cough, bronchoconstriction and mucosal secretion after cold exposure and hyperventilation after heat exposure. In the present investigation, we examined the activity of bronchopulmonary receptors in response to activators of thermo-sensitive transient receptor potential (TS-TRP) cation channels using an ex vivo rat lung preparation. Receptive fields in small bronchioles were probed with von Frey hair monofilaments, warm (50°C) or cold (8°C) saline or saline containing TS-TRP agonists. Among 233 fibers tested, 159 (68.2%) responded to heat (50°C). A large proportion of heat-responsive receptors (107/145) were also activated by capsaicin. Heat and capsaicin-evoked responses were both blocked by TRPV1 antagonist, capsazepine. Only 15.3% of airway receptors responded to cold, which was associated with sensitivity to TRPM8 agonist menthol but not to TRPA1 agonist cinnamaldehyde (CA). Moreover, cold-evoked responses was unaffected by TRPA1 antagonist HC-03001. Our observations suggest that TRPV1 and TRPM8 are involved in transducing heat and cold in the lower respiratory tract, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer

NASA Astrophysics Data System (ADS)

Delil, A. A. M.

2003-01-01

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single-component two-phase thermal control systems for various gravity environments.

A Correlation for Forced Convective Boiling Heat Transfer of Refrigerants in a Microfin Tube

NASA Astrophysics Data System (ADS)

Momoki, Satoru; Yu, Jian; Koyama, Shigeru; Fujii, Tetsu; Honda, Hiroshi

The experimental study is reported on the forced convective boiling of pure refrigerants HCFC22, HFC134a and HCFC123 flowing in a horizontal microfin tube. The local heat transfer coefficient defined based on the actual inside surface area is measured in the ranges of mass velocity of 200 to 400 kg/m2s, heat flux of 5 to 64 kW/m2 and reduced pressure of 0.07 to 0.24. Using the Chen-type model, a new correlation for microfin tubes is proposed considering the enhancement effect of microfins on both the convective heat transfer and the nucleate boiling components. In the convective heat transfer component, the correlation to predict the heat transfer coefficient of liquid-only flow is determined from preliminary experiments on single-phase flow in microfin tubes, and the two-phase flow enhancement factor is determined from the present experimental data. For the nucleate boiling component, the correlation of Takamatsu et al. for smooth tube is modified. The prediction of the present correlation agrees well with present experimental data, and is available for several microfin tubes which were tested by other researchers.

Seasonal variations in the chemical composition of particulate matter: a case study in the Po Valley. Part I: macro-components and mass closure.

PubMed

Perrino, C; Catrambone, M; Dalla Torre, S; Rantica, E; Sargolini, T; Canepari, S

2014-03-01

The seasonal variability in the mass concentration and chemical composition of atmospheric particulate matter (PM10 and PM2.5) was studied during a 2-year field study carried out between 2010 and 2012. The site of the study was the area of Ferrara (Po Valley, Northern Italy), which is characterized by frequent episodes of very stable atmospheric conditions in winter. Chemical analyses carried out during the study allowed the determination of the main components of atmospheric PM (macro-elements, ions, elemental carbon, organic matter) and a satisfactory mass closure was obtained. Accordingly, chemical components could be grouped into the main macro-sources of PM: soil, sea spray, inorganic compounds from secondary reactions, vehicular emission, organics from domestic heating, organics from secondary formation, and other sources. The more significant seasonal variations were observed for secondary inorganic species in the fine fraction of PM; these species were very sensitive to air mass age and thus to the frequency of stable atmospheric conditions. During the winter ammonium nitrate, the single species with the highest concentration, reached concentrations as high as 30 μg/m(3). The intensity of natural sources was fairly constant during the year; increases in natural aerosols were linked to medium and long-range transport episodes. The ratio of winter to summer concentrations was roughly 2 for combustion product, close to 3 for secondary inorganic species, and between 2 and 3 for organics. The winter increase of organics was due to poorer atmospheric dispersion and to the addition of the emission from domestic heating. A similar winter to summer ratio (around 3) was observed for the fine fraction of PM.

Transient responses of phosphoric acid fuel cell power plant system. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lu, Cheng-Yi

1983-01-01

An analytical and computerized study of the steady state and transient response of a phosphoric acid fuel cell (PAFC) system was completed. Parametric studies and sensitivity analyses of the PAFC system's operation were accomplished. Four non-linear dynamic models of the fuel cell stack, reformer, shift converters, and heat exchangers were developed based on nonhomogeneous non-linear partial differential equations, which include the material, component, energy balance, and electrochemical kinetic features. Due to a lack of experimental data for the dynamic response of the components only the steady state results were compared with data from other sources, indicating reasonably good agreement. A steady state simulation of the entire system was developed using, nonlinear ordinary differential equations. The finite difference method and trial-and-error procedures were used to obtain a solution. Using the model, a PAFC system, that was developed under NASA Grant, NCC3-17, was improved through the optimization of the heat exchanger network. Three types of cooling configurations for cell plates were evaluated to obtain the best current density and temperature distributions. The steady state solutions were used as the initial conditions in the dynamic model. The transient response of a simplified PAFC system, which included all of the major components, subjected to a load change was obtained. Due to the length of the computation time for the transient response calculations, analysis on a real-time computer was not possible. A simulation of the real-time calculations was developed on a batch type computer. The transient response characteristics are needed for the optimization of the design and control of the whole PAFC system. All of the models, procedures and simulations were programmed in Fortran and run on IBM 370 computers at Cleveland State University and the NASA Lewis Research Center.

Constitutive Theory Developed for Monolithic Ceramic Materials

NASA Technical Reports Server (NTRS)

Janosik, Lesley A.

1998-01-01

With the increasing use of advanced ceramic materials in high-temperature structural applications such as advanced heat engine components, the need arises to accurately predict thermomechanical behavior that is inherently time-dependent and that is hereditary in the sense that the current behavior depends not only on current conditions but also on the material's thermomechanical history. Most current analytical life prediction methods for both subcritical crack growth and creep models use elastic stress fields to predict the time-dependent reliability response of components subjected to elevated service temperatures. Inelastic response at high temperatures has been well documented in the materials science literature for these material systems, but this issue has been ignored by the engineering design community. From a design engineer's perspective, it is imperative to emphasize that accurate predictions of time-dependent reliability demand accurate stress field information. Ceramic materials exhibit different time-dependent behavior in tension and compression. Thus, inelastic deformation models for ceramics must be constructed in a fashion that admits both sensitivity to hydrostatic stress and differing behavior in tension and compression. A number of constitutive theories for materials that exhibit sensitivity to the hydrostatic component of stress have been proposed that characterize deformation using time-independent classical plasticity as a foundation. However, none of these theories allow different behavior in tension and compression. In addition, these theories are somewhat lacking in that they are unable to capture the creep, relaxation, and rate-sensitive phenomena exhibited by ceramic materials at high temperatures. The objective of this effort at the NASA Lewis Research Center has been to formulate a macroscopic continuum theory that captures these time-dependent phenomena. Specifically, the effort has focused on inelastic deformation behavior associated with these service conditions by developing a multiaxial viscoplastic constitutive model that accounts for time-dependent hereditary material deformation (such as creep and stress relaxation) in monolithic structural ceramics. Using continuum principles of engineering mechanics, we derived the complete viscoplastic theory from a scalar dissipative potential function.

Sensitizing and Eliciting Capacity of Egg White Proteins in BALB/c Mice As Affected by Processing.

PubMed

Pablos-Tanarro, Alba; Lozano-Ojalvo, Daniel; Martínez-Blanco, Mónica; López-Fandiño, Rosina; Molina, Elena

2017-06-07

This study assesses to what extent technological processes that lead to different degrees of denaturation of egg white proteins affect their allergenicity. We focused on heat (80 °C, 10 min) and high-pressure (400 MPa and 37 °C, 10 min) treatments and used a BALB/c mouse model of food allergy. Oral sensitization to egg white using cholera toxin as adjuvant induced the production of IgE and IgG1 isotypes and led to severe clinical signs following challenge with the allergen. Extensive protein denaturation caused by heat treatment increased its ability to induce Th1 responses and reduced both its sensitizing and eliciting capacity. Heated egg white stimulated the production of IgE over IgG1 antibodies directed, at least in part, toward new epitopes exposed as a result of heat treatment. Conversely, partial denaturation caused by high-pressure treatment increased the ability of egg white to stimulate Th2 responses and its allergenic potential.

Sensitive power compensated scanning calorimeter for analysis of phase transformations in small samples

NASA Astrophysics Data System (ADS)

Lopeandía, A. F.; Cerdó, L. l.; Clavaguera-Mora, M. T.; Arana, Leonel R.; Jensen, K. F.; Muñoz, F. J.; Rodríguez-Viejo, J.

2005-06-01

We have designed and developed a sensitive scanning calorimeter for use with microgram or submicrogram, thin film, or powder samples. Semiconductor processing techniques are used to fabricate membrane based microreactors with a small heat capacity of the addenda, 120nJ/K at room temperature. At heating rates below 10K/s the heat released or absorbed by the sample during a given transformation is compensated through a resistive Pt heater by a digital controller so that the calorimeter works as a power compensated device. Its use and dynamic sensitivity is demonstrated by analyzing the melting behavior of thin films of indium and high density polyethylene. Melting enthalpies in the range of 40-250μJ for sample masses on the order of 1.5μg have been measured with accuracy better than 5% at heating rates ˜0.2K/s. The signal-to-noise ratio, limited by the electronic setup, is 200nW.

Low-cost functional plasticity of TRPV1 supports heat tolerance in squirrels and camels.

PubMed

Laursen, Willem J; Schneider, Eve R; Merriman, Dana K; Bagriantsev, Sviatoslav N; Gracheva, Elena O

2016-10-04

The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system. Here, we show that thirteen-lined ground squirrels (Ictidomys tridecemlineatus) and Bactrian camels (Camelus ferus) express TRPV1 orthologs with dramatically reduced temperature sensitivity. The loss of sensitivity is restricted to temperature and does not affect capsaicin or acid responses, thereby maintaining a role for TRPV1 as a detector of noxious chemical cues. We show that heat sensitivity can be reengineered in both TRPV1 orthologs by a single amino acid substitution in the N-terminal ankyrin-repeat domain. Conversely, reciprocal mutations suppress heat sensitivity of rat TRPV1, supporting functional conservation of the residues. Our studies suggest that squirrels and camels co-opt a common molecular strategy to adapt to hot environments by suppressing the efficiency of TRPV1-mediated heat detection at the level of somatosensory neurons. Such adaptation is possible because of the remarkable functional flexibility of the TRPV1 molecule, which can undergo profound tuning at the minimal cost of a single amino acid change.

Low-cost functional plasticity of TRPV1 supports heat tolerance in squirrels and camels

PubMed Central

Laursen, Willem J.; Merriman, Dana K.; Bagriantsev, Sviatoslav N.; Gracheva, Elena O.

2016-01-01

The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system. Here, we show that thirteen-lined ground squirrels (Ictidomys tridecemlineatus) and Bactrian camels (Camelus ferus) express TRPV1 orthologs with dramatically reduced temperature sensitivity. The loss of sensitivity is restricted to temperature and does not affect capsaicin or acid responses, thereby maintaining a role for TRPV1 as a detector of noxious chemical cues. We show that heat sensitivity can be reengineered in both TRPV1 orthologs by a single amino acid substitution in the N-terminal ankyrin-repeat domain. Conversely, reciprocal mutations suppress heat sensitivity of rat TRPV1, supporting functional conservation of the residues. Our studies suggest that squirrels and camels co-opt a common molecular strategy to adapt to hot environments by suppressing the efficiency of TRPV1-mediated heat detection at the level of somatosensory neurons. Such adaptation is possible because of the remarkable functional flexibility of the TRPV1 molecule, which can undergo profound tuning at the minimal cost of a single amino acid change. PMID:27638213

The metallurgical structure and mechanical properties at low temperature of Nitronic 40 with particular reference to its use in the construction of models for cryogenic wind tunnels

NASA Technical Reports Server (NTRS)

Wigley, D. A.

1982-01-01

Nitronic 40 was chosen for the construction of Pathfinder I, an R & D model for use in the National Transonic Facility, because of its good mechanical properties at cryogenic temperatures. Nitronic 40 contains delta ferrite and is in a sensitized condition. Heat treatments carried out to remove residual stresses also caused further sensitization. Experiments showed that heat treatment followed by cryoquenching removed the sensitization without creating residual stresses. Heat treatment at temperatures of 2200 F was used to remove the delta ferrite but with little success and at the cost of massive grain growth. The implications of using degraded Nitronic 40 for cryogenic wind tunnel models are discussed, together with possible acceptance criteria.

Miniature FBG-based fluidic flowmeter to measure hot oil and water

NASA Astrophysics Data System (ADS)

Liu, Zhengyong; Htein, Lin; Cheng, Lun-Kai; Martina, Quincy; Jansen, Rob; Tam, Hwa-Yaw

2017-04-01

In this paper, we present a miniature fluidic flowmeter based on a packaged FBG and laser-heated fibers. The flow rates of water and hydraulic oil were measured by utilizing the proposed flowmeter. The measured results exhibited good sensitivity of 0.339 nm/(m/s) for water and 0.578 nm/(m/s) for oil flow. Experimental results showed that the sensitivity of the fluidic flow sensor is depending on the heat capacity of the fluids, where the fluid with higher heat capacity has higher sensitivity and lower detection limit at the same measurement condition. The real-time flow rates measured by the proposed sensor and a commercial flowmeter installed in the test rig were also compared, demonstrating good agreement with correlation coefficient of 0.9974.

Floating loop method for cooling integrated motors and inverters using hot liquid refrigerant

DOEpatents

Hsu, John S.; Ayers, Curtis W.; Coomer, Chester; Marlino, Laura D.

2007-03-20

A method for cooling vehicle components using the vehicle air conditioning system comprising the steps of: tapping the hot liquid refrigerant of said air conditioning system, flooding a heat exchanger in the vehicle component with said hot liquid refrigerant, evaporating said hot liquid refrigerant into hot vapor refrigerant using the heat from said vehicle component, and returning said hot vapor refrigerant to the hot vapor refrigerant line in said vehicle air conditioning system.

Potential cooling of an accretion-heated neutron star crust in the low-mass X-ray binary 1RXS J180408.9-342058

NASA Astrophysics Data System (ADS)

Parikh, A. S.; Wijnands, R.; Degenaar, N.; Ootes, L. S.; Page, D.; Altamirano, D.; Cackett, E. M.; Deller, A. T.; Gusinskaia, N.; Hessels, J. W. T.; Homan, J.; Linares, M.; Miller, J. M.; Miller-Jones, J. C. A.

2017-04-01

We have monitored the transient neutron star low-mass X-ray binary 1RXS J180408.9-342058 in quiescence after its ˜4.5 month outburst in 2015. The source has been observed using Swift and XMM-Newton. Its X-ray spectra were dominated by a thermal component. The thermal evolution showed a gradual X-ray luminosity decay from ˜18 × 1032 to ˜4 × 1032 (D/5.8 kpc)2 erg s-1 between ˜8 and ˜379 d in quiescence, and the inferred neutron star surface temperature (for an observer at infinity; using a neutron star atmosphere model) decreased from ˜100 to ˜71 eV. This can be interpreted as cooling of an accretion-heated neutron star crust. Modelling the observed temperature curve (using nscool) indicated that the source required ˜1.9 MeV per accreted nucleon of shallow heating in addition to the standard deep crustal heating to explain its thermal evolution. Alternatively, the decay could also be modelled without the presence of deep crustal heating, only having a shallow heat source (again ˜1.9 MeV per accreted nucleon was required). However, the XMM-Newton data statistically required an additional power-law component. This component contributed ˜30 per cent of the total unabsorbed flux in 0.5-10 keV energy range. The physical origin of this component is unknown. One possibility is that it arises from low-level accretion. The presence of this component in the spectrum complicates our cooling crust interpretation because it might indicate that the smooth luminosity and temperature decay curves we observed may not be due to crust cooling but due to some other process.

Sensitivity of a climatologically-driven sea ice model to the ocean heat flux

NASA Technical Reports Server (NTRS)

Parkinson, C. L.; Good, M. R.

1982-01-01

Ocean heat flux sensitivity was studied on a numerical model of sea ice covering the Weddell Sea region of the southern ocean. The model is driven by mean monthly climatological atmospheric variables. For each model run, the ocean heat flux is uniform in both space and time. Ocean heat fluxes below 20 W m to the minus 2 power do not provide sufficient energy to allow the ice to melt to its summertime thicknesses and concentrations by the end of the 14 month simulation, whereas ocean heat fluxes of 30 W m to the minus 2 power and above result in too much ice melt, producing the almost total disappearance of ice in the Weddell Sea by the end of the 14 months. These results are dependent on the atmospheric forcing fields.

Slow Temporal Summation of Pain for Assessment of Central Pain Sensitivity and Clinical Pain of Fibromyalgia Patients

PubMed Central

Staud, Roland; Weyl, Elizabeth E.; Riley, Joseph L.; Fillingim, Roger B.

2014-01-01

Background In healthy individuals slow temporal summation of pain or wind-up (WU) can be evoked by repetitive heat-pulses at frequencies of ≥.33 Hz. Previous WU studies have used various stimulus frequencies and intensities to characterize central sensitization of human subjects including fibromyalgia (FM) patients. However, many trials demonstrated considerable WU-variability including zero WU or even wind-down (WD) at stimulus intensities sufficient for activating C-nociceptors. Additionally, few WU-protocols have controlled for contributions of individual pain sensitivity to WU-magnitude, which is critical for WU-comparisons. We hypothesized that integration of 3 different WU-trains into a single WU-response function (WU-RF) would not only control for individuals’ pain sensitivity but also better characterize their central pain responding including WU and WD. Methods 33 normal controls (NC) and 38 FM patients participated in a study of heat-WU. We systematically varied stimulus intensities of.4 Hz heat-pulse trains applied to the hands. Pain summation was calculated as difference scores of 1st and 5th heat-pulse ratings. WU-difference (WU-Δ) scores related to 3 heat-pulse trains (44°C, 46°C, 48°C) were integrated into WU-response functions whose slopes were used to assess group differences in central pain sensitivity. WU-aftersensations (WU-AS) at 15 s and 30 s were used to predict clinical FM pain intensity. Results WU-Δ scores linearly accelerated with increasing stimulus intensity (p<.001) in both groups of subjects (FM>NC) from WD to WU. Slope of WU-RF, which is representative of central pain sensitivity, was significantly steeper in FM patients than NC (p<.003). WU-AS predicted clinical FM pain intensity (Pearson’s r = .4; p<.04). Conclusions Compared to single WU series, WU-RFs integrate individuals’ pain sensitivity as well as WU and WD. Slope of WU-RFs was significantly different between FM patients and NC. Therefore WU-RF may be useful for assessing central sensitization of chronic pain patients in research and clinical practice. PMID:24558475

Droplet Evaporator For High-Capacity Heat Transfer

NASA Technical Reports Server (NTRS)

Valenzuela, Javier A.

1993-01-01

Proposed heat-exchange scheme boosts heat transfer per unit area. Key component is generator that fires uniform size droplets of subcooled liquid at hot plate. On impact, droplets spread out and evaporate almost instantly, removing heat from plate. In practice, many generator nozzles arrayed over evaporator plate.

Heat processing of peanut seed enhances the sensitization potential of the major peanut allergen Ara h 6.

PubMed

Guillon, Blanche; Bernard, Hervé; Drumare, Marie-Françoise; Hazebrouck, Stéphane; Adel-Patient, Karine

2016-12-01

Processing of food has been shown to impact IgE binding and functionality of food allergens. In the present study, we investigated the impact of heat processing on the sensitization capacity of Ara h 6, a major peanut allergen and one of the most potent elicitors of the allergic reaction. Peanut extracts obtained from raw or heat-processed peanut and some fractions thereof were biochemically and immunochemically characterized. These extracts/fractions, purified Ara h 6, or recombinant Ara h 6 including Ara h 6 mutants lacking disulfide bridges were used in in vitro digestion tests and mouse models of experimental sensitization. Peanut roasting led to the formation of complexes of high molecular weight, notably between Ara h 6 and Ara h 1, which supported the induction of IgE specific to native Ara h 6. On the contrary, a fraction containing free monomeric 2S albumins or purified native Ara h 6 displayed no intrinsic allergenicity. In addition to complex formation, heat denaturation and/or partial destabilization enhanced Ara h 6 immunogenicity and increased its sensitivity to digestion. These results suggest that sensitization potency and IgE binding capacity can be supported by different structures, modified and/or produced during food processing in interaction with other food constituents. © 2016 The Authors. Molecular Nutrition & Food Research published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Small Heat Shock Proteins Are Novel Common Determinants of Alcohol and Nicotine Sensitivity in Caenorhabditis elegans

PubMed Central

Johnson, James R.; Rajamanoharan, Dayani; McCue, Hannah V.; Rankin, Kim

2016-01-01

Addiction to drugs is strongly determined by multiple genetic factors. Alcohol and nicotine produce distinct pharmacological effects within the nervous system through discrete molecular targets; yet, data from family and twin analyses support the existence of common genetic factors for addiction in general. The mechanisms underlying addiction, however, are poorly described and common genetic factors for alcohol and nicotine remain unidentified. We investigated the role that the heat shock transcription factor, HSF-1, and its downstream effectors played as common genetic modulators of sensitivity to addictive substances. Using Caenorhabditis elegans, an exemplary model organism with substance dose-dependent responses similar to mammals, we demonstrate that HSF-1 altered sensitivity to both alcohol and nicotine. Using a combination of a targeted RNAi screen of downstream factors and transgenic approaches we identified that these effects were contingent upon the constitutive neuronal expression of HSP-16.48, a small heat shock protein (HSP) homolog of human α-crystallin. Furthermore we demonstrated that the function of HSP-16.48 in drug sensitivity surprisingly was independent of chaperone activity during the heat shock stress response. Instead we identified a distinct domain within the N-terminal region of the HSP-16.48 protein that specified its function in comparison to related small HSPs. Our findings establish and characterize a novel genetic determinant underlying sensitivity to diverse addictive substances. PMID:26773049

Synchronizing Two AGCMs via Ocean-Atmosphere Coupling (Invited)

NASA Astrophysics Data System (ADS)

Kirtman, B. P.

2009-12-01

A new approach for fusing or synchronizing to very different Atmospheric General Circulation Models (AGCMs) is described. The approach is also well suited for understand why two different coupled models have such large differences in their respective climate simulations. In the application presented here, the differences between the coupled models using the Center for Ocean-Land-Atmosphere Studies (COLA) and the National Center for Atmospheric Research (NCAR) atmospheric general circulation models (AGCMs) are examined. The intent is to isolate which component of the air-sea fluxes is most responsible for the differences between the coupled models and for the errors in their respective coupled simulations. The procedure is to simultaneously couple the two different atmospheric component models to a single ocean general circulation model (OGCM), in this case the Modular Ocean Model (MOM) developed at the Geophysical Fluid Dynamics Laboratory (GFDL). Each atmospheric component model experiences the same SST produced by the OGCM, but the OGCM is simultaneously coupled to both AGCMs using a cross coupling strategy. In the first experiment, the OGCM is coupled to the heat and fresh water flux from the NCAR AGCM (Community Atmospheric Model; CAM) and the momentum flux from the COLA AGCM. Both AGCMs feel the same SST. In the second experiment, the OGCM is coupled to the heat and fresh water flux from the COLA AGCM and the momentum flux from the CAM AGCM. Again, both atmospheric component models experience the same SST. By comparing these two experimental simulations with control simulations where only one AGCM is used, it is possible to argue which of the flux components are most responsible for the differences in the simulations and their respective errors. Based on these sensitivity experiments we conclude that the tropical ocean warm bias in the COLA coupled model is due to errors in the heat flux, and that the erroneous westward shift in the tropical Pacific cold tongue minimum in the NCAR model is due errors in the momentum flux. All the coupled simulations presented here have warm biases along the eastern boundary of the tropical oceans suggesting that the problem is common to both AGCMs. In terms of interannual variability in the tropical Pacific, the CAM momentum flux is responsible for the erroneous westward extension of the sea surface temperature anomalies (SSTA) and errors in the COLA momentum flux cause the erroneous eastward migration of the El Niño-Southern Oscillation (ENSO) events. These conclusions depend on assuming that the error due to the OGCM can be neglected.

Simulation of heat storages and associated heat budgets in the Pacific Ocean: 2. Interdecadal timescale

NASA Astrophysics Data System (ADS)

Auad, Guillermo; Miller, Arthur J.; White, Warren B.

1998-11-01

We use a primitive equation isopycnal model of the Pacific Ocean to simulate and diagnose the anomalous heat balance on interdecadal timescales associated with heat storage changes observed from 1970-1988 in the expendable bathythermograph (XBT) data set. Given the smallness of the interdecadal signals compared to the El Niño-Southern Oscillation (ENSO) signal, the agreement between model and observations is remarkably good. The total anomalous heat balance is made up of two parts, the diabatic part (from the model temperature equation) and the adiabatic part (from the model mass conservation equation) due to thermocline heave. We therefore describe our analysis of both the total and diabatic anomalous heat balances in four areas of the tropical and subtropical North Pacific Ocean in the upper 400 m. The interdecadal total (diabatic plus adiabatic) heat balance in the North Pacific Ocean is characterized by a complicated interplay of different physical processes, especially revealed in basin-scale averages of the heat budget components that have comparable amounts of variance. In smaller subregions, simpler balances hold. For example, in the western equatorial Pacific (area 1) the total heat content tendency term is nearly zero, so that a simple balance exists between surface heat flux, vertical heat transport, and horizontal mixing. In the western subtropical Pacific the total heat content tendency balances the three-dimensional divergence of the heat flux. We speculate that this complexity is indicative of multiple physical mechanisms involved in the generation of North Pacific interdecadal variability. The diabatic heat balance north of 24°N, a region of special interest to The World Ocean Circulation Experiment (WOCE), can be simplified to a balance between the tendency term, surface heat flux, and meridional advection, the last term dominated by anomalous advection of mean temperature gradients. For the western equatorial region the diabatic heat content tendency is nearly zero and the steady balance involves simply horizontal advection and the surface heat flux, which at these latitudes has a damping role in the model. An important finding of this study is the identification of two interdecadal timescales, roughly 10 and 20 years, both similar to those reported by other investigators in recent years. [Tourre et al., 1998; Latif and Barnett, 1994; Robertson, 1995; White et al, 1997; Gu and Philander, 1997; Jacobs et al., 1994]. The 20-year timescale is only present in diabatic heat budget components, while the 10-year timescale is present in both diabatic and adiabatic components. The 10-year timescale can also be seen in the surface heat flux time series, but it occurs in the ocean adiabatic components which demonstrates the importance of oceanic adjustment through Rossby wave dynamics on decadal timescales.

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.

Membrane-Based Water Evaporator for a Space Suit

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; McCann, Charles J.; O'Connell, Mary K.; Andrea, Scott

2004-01-01

A membrane-based water evaporator has been developed that is intended to serve as a heat-rejection device for a space suit. This evaporator would replace the current sublimator that is sensitive to contamination of its feedwater. The design of the membrane-based evaporator takes advantage of recent advances in hydrophobic micropore membranes to provide robust heat rejection with much less sensitivity to contamination. The low contamination sensitivity allows use of the heat transport loop as feedwater, eliminating the need for the separate feedwater system used for the sublimator. A cross section of the evaporator is shown in the accompanying figure. The space-suit cooling loop water flows into a distribution plenum, through a narrow annulus lined on both sides with a hydrophobic membrane, into an exit plenum, and returns to the space suit. Two perforated metal tubes encase the membranes and provide structural strength. Evaporation at the membrane inner surface dissipates the waste heat from the space suit. The water vapor passes through the membrane, into a steam duct and is vented to the vacuum environment through a back-pressure valve. The back-pressure setting can be adjusted to regulate the heat-rejection rate and the water outlet temperature.

Heat exchanger containing a component capable of discontinuous movement

DOEpatents

Wilson, D.G.

1993-11-09

Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices. 11 figures.

Heat exchanger containing a component capable of discontinuous movement

DOEpatents

Wilson, David Gordon

2001-04-17

Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

Heat exchanger containing a component capable of discontinuous movement

DOEpatents

Wilson, David G.

1993-01-01

Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

Heat exchanger containing a component capable of discontinuous movement

DOEpatents

Wilson, David Gordon

2002-01-01

Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

NASA Technical Reports Server (NTRS)

Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam;

The impact of heat waves on children's health: a systematic review.

PubMed

Xu, Zhiwei; Sheffield, Perry E; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

2014-03-01

Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended.

The impact of heat waves on children's health: a systematic review

NASA Astrophysics Data System (ADS)

Xu, Zhiwei; Sheffield, Perry E.; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

2014-03-01

Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended.

Thermionic combustor application to combined gas and steam turbine power plants

NASA Astrophysics Data System (ADS)

Miskolczy, G.; Wang, C. C.; Lieb, D. P.; Margulies, A. E.; Fusegni, L. J.; Lovell, B. J.

A design for the insertion of thermionic converters into the wall of a conventional combustor to produce electricity in a topping cycle is described, and a study for applications in gas and steam generators of 70 and 30 MW is evaluated for engineering and economic feasibility. Waste heat from the thermionic elements is used to preheat the combustor air; the heat absorbed by the elements plus further quenching of the exhaust gases with ammonia is projected to reduce NO(x) emissions to acceptable levels. Schematics, flow diagrams, and components of a computer model for cost projections are provided. It was found that temperatures around the emitters must be maintained above 1,600 K, with maximum efficiency and allowable temperature at 1,800 K, while collectors generate maximally at 950 K, with a corresponding work function of 1.5 eV. Cost sensitive studies indicate an installed price of $475/kW for the topping cycle, with improvements in thermionic converter characteristics bringing the cost to $375/kW at a busbar figure of 500 mills/kWh.

Novel process chain for hot metal gas forming of ferritic stainless steel 1.4509

NASA Astrophysics Data System (ADS)

Mosel, André; Lambarri, Jon; Degenkolb, Lars; Reuther, Franz; Hinojo, José Luis; Rößiger, Jörg; Eurich, Egbert; Albert, André; Landgrebe, Dirk; Wenzel, Holger

2018-05-01

Exhaust gas components of automobiles are often produced in ferritic stainless steel 1.4509 due to the low thermal expansion coefficient and the low material price. Until now, components of the stainless steel with complex geometries have been produced in series by means of multi-stage hydroforming at room temperature with intermediate annealing operations. The application of a single-stage hot-forming process, also referred to as hot metal gas forming (HMGF), offers great potential to significantly reduce the production costs of such components. The article describes a novel process chain for the HMGF process. Therefore the tube is heated in two steps. After pre-heating of the semi-finished product outside the press, the tube is heated up to forming start temperature by means of a tool-integrated conductive heating before forming. For the tube of a demonstrator geometry, a simulation model for the conduction heating was set up. In addition to the tool development for this process, experimental results are also described for the production of the demonstrator geometry.

Effects of wastewater sludge and its detergents on the stability of rotavirus

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

Ward, R.L.; Ashley, C.S.

1980-06-01

Wastewater sludge reduced the heat required to inactivate rotavirus SA-11, and ionic detergents were identified as the sludge components responsible for this effect. A similar result was found previously with reovirus. The quantitative effects of individual ionic detergents on rotavirus and reovirus were very different, and rotavirus was found to be extremely sensitive to several of these detergents. However, neither virus was destabilized by nonionic detergents. On the contrary, rotavirus was stabilized by a nonionic detergent against the potent destabilizing effects of the ionic detergent sodium dodecyl sulfate. The destabilizing effects of both cationic and anionic detergents on rotavirus weremore » greatly altered by changes in the pH of the medium.« less

Inhibition of protein synthesis in intact HeLa cells by Shigella dysenteriae 1 toxin.

PubMed

Brown, J E; Rothman, S W; Doctor, B P

1980-07-01

Shiga toxin purified to near homogeneity from cell lysates of Shigella dysenteriae 1 inhibited protein and deoxyribonucle acid syntheses in intact HeLa cells. Inhibition was dependent on toxin concentration and time of incubation. A minimal latent period of 30 min was observed with saturating doses of toxin. Ribonucleic acid synthesis, uptake of alpha-aminoisobutyric acid, and maintenance of intracellular K+ concentrations were not affected until well after maximal inhibition of protein and deoxyribonucleic acid syntheses. The inhibitory effect of toxin was sensitive to heat inactivation and was prevented by antibody neutralization. Several cytotoxic components were separated by polyacrylamide gel electrophoresis of the purified toxin preparations; all inhibited protein and deoxyribonucleic acid syntheses equally.

Numerical Study of High Heat Flux Performances of Flat-Tile Divertor Mock-ups with Hypervapotron Cooling Concept

NASA Astrophysics Data System (ADS)

Chen, Lei; Liu, Xiang; Lian, Youyun; Cai, Laizhong

2015-09-01

The hypervapotron (HV), as an enhanced heat transfer technique, will be used for ITER divertor components in the dome region as well as the enhanced heat flux first wall panels. W-Cu brazing technology has been developed at SWIP (Southwestern Institute of Physics), and one W/CuCrZr/316LN component of 450 mm×52 mm×166 mm with HV cooling channels will be fabricated for high heat flux (HHF) tests. Before that a relevant analysis was carried out to optimize the structure of divertor component elements. ANSYS-CFX was used in CFD analysis and ABAQUS was adopted for thermal-mechanical calculations. Commercial code FE-SAFE was adopted to compute the fatigue life of the component. The tile size, thickness of tungsten tiles and the slit width among tungsten tiles were optimized and its HHF performances under International Thermonuclear Experimental Reactor (ITER) loading conditions were simulated. One brand new tokamak HL-2M with advanced divertor configuration is under construction in SWIP, where ITER-like flat-tile divertor components are adopted. This optimized design is expected to supply valuable data for HL-2M tokamak. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2011GB110001 and 2011GB110004)

Coolant and ambient temperature control for chillerless liquid cooled data centers

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Simons, Robert E.

2016-02-02

Cooling control methods include measuring a temperature of air provided to a plurality of nodes by an air-to-liquid heat exchanger, measuring a temperature of at least one component of the plurality of nodes and finding a maximum component temperature across all such nodes, comparing the maximum component temperature to a first and second component threshold and comparing the air temperature to a first and second air threshold, and controlling a proportion of coolant flow and a coolant flow rate to the air-to-liquid heat exchanger and the plurality of nodes based on the comparisons.

Design component method for sensitivity analysis of built-up structures

NASA Technical Reports Server (NTRS)

Choi, Kyung K.; Seong, Hwai G.

1986-01-01

A 'design component method' that provides a unified and systematic organization of design sensitivity analysis for built-up structures is developed and implemented. Both conventional design variables, such as thickness and cross-sectional area, and shape design variables of components of built-up structures are considered. It is shown that design of components of built-up structures can be characterized and system design sensitivity expressions obtained by simply adding contributions from each component. The method leads to a systematic organization of computations for design sensitivity analysis that is similar to the way in which computations are organized within a finite element code.

Sensitivity, Specificity, and Predictive Values of Pediatric Metabolic Syndrome Components in Relation to Adult Metabolic Syndrome: The Princeton LRC Follow-up Study

PubMed Central

Huang, Terry T-K; Nansel, Tonja R.; Belsheim, Allen R.; Morrison, John A.

2008-01-01

Objective To estimate the sensitivity, specificity, and predictive values of pediatric metabolic syndrome (MetS) components (obesity, fasting glucose, triglycerides, high-density lipoprotein, and blood pressure) at various cutoffs in relation to adult MetS. Study design Data from the NHLBI Lipid Research Clinics (LRC) Princeton Prevalence Study (1973–76) and the Princeton Follow-up Study (PFS, 2000-4) were used to calculate sensitivity, specificity, and positive and negative predictive values for each component at a given cutoff, as well as for aggregates of components. Results Individual pediatric components alone showed low to moderate sensitivity, high specificity, and moderate predictive values in relation to adult MetS. When all five pediatric MetS components were considered, the presence of at least one abnormality had higher sensitivity for adult MetS than individual components alone. When multiple abnormalities were mandatory for MetS, positive predictive value was high and sensitivity was low. Childhood body mass alone showed neither high sensitivity nor high positive predictive value for adult MetS. Conclusions Considering multiple metabolic variables in childhood can improve the predictive utility for adult MetS, compared to each component or body mass alone. MetS variables may be useful for identifying some at risk children for prevention interventions. PMID:18206687

Heat-load simulator for heat sink design

NASA Technical Reports Server (NTRS)

Dunleavy, A. M.; Vaughn, T. J.

1968-01-01

Heat-load simulator is fabricated from 1/4-inch aluminum plate with a contact surface equal in dimensions and configuration to those of the electronic installation. The method controls thermal output to simulate actual electronic component thermal output.

The role of latent heat in kinetic energy conversions of South Pacific cyclones

NASA Technical Reports Server (NTRS)

Kann, Deirdre M.; Vincent, Dayton G.

1986-01-01

The four-dimensional behavior of cyclone systems in the South Pacific Convergence Zone (SPCZ) is analyzed. Three cyclone systems, which occurred during the period from January 10-16, 1979, are examined using the data collected during the first special observing period of the FGGE. The effects of latent heating on the life cycles of the cyclones are investigated. Particular attention is given to the conversions of eddy available potential energy to eddy kinetic energy and of mean kinetic energy to eddy kinetic energy. The net radiation profile, sensible heat flux, total field of vertical motion, and latent heat component were computed. The life cycles of the cyclones are described. It is observed that the latent heating component accounts for nearly all the conversion in the three cyclones, and latent heating within the SPCZ is the major source of eddy kinetic energy for the cyclones.

What do they know about Heat and Heat Conduction? A case study to excavate Pre-service Physics Teachers’ Mental Model in Heat and Heat Conduction

NASA Astrophysics Data System (ADS)

Sari, I. M.

2017-02-01

Teacher plays a crucial role in Education. Helping students construct scientifically mental model is one of obligation of Physics Education Department of Teacher Education Institute that produce physics teacher. Excavating students’ mental model is necessary to be done in physics education. This research was first to identify 23 physics students’ mental model of heat and heat conduction. A series of semi-structured interviews was conducted to excavate the students’ understanding of heat and mental models on heat conduction. The students who involved in this study come from different level from sophomore to master degree in Physics Education Department. This study adopted a constant comparison method to obtain the patterns of the participants’ responses through the students’ writing, drawing and verbal utterances. The framework for assessing mental model and the instruments were adopted and adapted from Chiou and Anderson (2010). We also compared the students’ understanding of heat and mental models on heat conduction. The result shows that Heat is treated as Intrinsic property, material substances, and caloric flow. None of students expressed heat as transfer of thermal energy. Moreover, there are two kinds of students’ fundamental component of mental model in heat conduction were found: medium and molecules. Students understanding of heat and fundamental components of mental model in heat conduction are not resulted from running mental model.

Asymmetric resonance response analysis of a thermally excited silicon microcantilever for mass-sensitive nanoparticle detection

NASA Astrophysics Data System (ADS)

Bertke, Maik; Hamdana, Gerry; Wu, Wenze; Wasisto, Hutomo Suryo; Peiner, Erwin

2017-06-01

The asymmetric resonance responses of a thermally actuated silicon microcantilever of a portable, cantilever-based nanoparticle detector (Cantor) is analysed. For airborne nanoparticle concentration measurements, the cantilever is excited in its first in-plane bending mode by an integrated p-type heating actuator. The mass-sensitive nanoparticle (NP) detection is based on the resonance frequency (f0) shifting due to the deposition of NPs. A homemade phase-locked loop (PLL) circuit is developed for tracking of f0. For deflection sensing the cantilever contains an integrated piezo-resistive Wheatstone bridge (WB). A new fitting function based on the Fano resonance is proposed for analysing the asymmetric resonance curves including a method for calculating the quality factor Q from the fitting parameters. To obtain a better understanding, we introduce an electrical equivalent circuit diagram (ECD) comprising a series resonant circuit (SRC) for the cantilever resonator and voltage sources for the parasitics, which enables us to simulate the asymmetric resonance response and discuss the possible causes. Furthermore, we compare the frequency response of the on-chip thermal excitation with an external excitation using an in-plane piezo actuator revealing parasitic heating of the WB as the origin of the asymmetry. Moreover, we are able to model the phase component of the sensor output using the ECD. Knowing and understanding the phase response is crucial to the design of the PLL and thus the next generation of Cantor.

Effects of intravenous propranolol on heat pain sensitivity in healthy men.

PubMed

Schweinhardt, P; Abulhasan, Y B; Koeva, V; Balderi, T; Kim, D J; Alhujairi, M; Carli, F

2013-05-01

Clinical studies have shown opioid-sparing effects of β-adrenergic antagonists perioperatively and β-blockers are being investigated for chronic musculoskeletal pain. However, the direct analgesic effects of β-blockers have rarely been examined in healthy humans. In a randomized, counter-balanced, double-blind, within-subject crossover design, we tested the effect of the lipophilic β-blocker propranolol (0.035 mg/kg body weight i.v.) on heat pain sensitivity in 39 healthy males, compared with placebo. To test for peripheral versus central effects, the peripherally acting β-blocker sotalol was also examined. Experimental stimuli were brief superficial noxious heat stimuli applied to the volar forearm. Non-painful cold stimuli were included to test for specificity. Sedation, mood and anxiety were assessed to investigate potential mechanisms underlying any analgesic effect. β-blocker effects on blood pressure were incorporated into the analysis because of a known inverse relationship between pain sensitivity and systolic blood pressure. Propranolol significantly decreased perceived intensity of heat pain stimuli but only in participants with small propranolol-induced blood pressure decreases. Even in this group, the effect was small (4%). Propranolol did not influence perceived intensity of non-noxious stimuli and had no effect on sedation, anxiety or mood. Sotalol did not influence heat pain sensitivity. Propranolol decreased pain sensitivity but its analgesic effects were small and counteracted by blood pressure decreases. The analgesic effects were not mediated by peripheral β-receptor blockade, sedation, mood or anxiety. The small effect indicates that the utility of β-blockers for clinical pain must be related to factors that do not play a significant role for experimental pain. © 2012 European Federation of International Association for the Study of Pain Chapters.

Exact harmonic solutions to Guyer-Krumhansl-type equation and application to heat transport in thin films

NASA Astrophysics Data System (ADS)

Zhukovsky, K.; Oskolkov, D.

2018-03-01

A system of hyperbolic-type inhomogeneous differential equations (DE) is considered for non-Fourier heat transfer in thin films. Exact harmonic solutions to Guyer-Krumhansl-type heat equation and to the system of inhomogeneous DE are obtained in Cauchy- and Dirichlet-type conditions. The contribution of the ballistic-type heat transport, of the Cattaneo heat waves and of the Fourier heat diffusion is discussed and compared with each other in various conditions. The application of the study to the ballistic heat transport in thin films is performed. Rapid evolution of the ballistic quasi-temperature component in low-dimensional systems is elucidated and compared with slow evolution of its diffusive counterpart. The effect of the ballistic quasi-temperature component on the evolution of the complete quasi-temperature is explored. In this context, the influence of the Knudsen number and of Cauchy- and Dirichlet-type conditions on the evolution of the temperature distribution is explored. The comparative analysis of the obtained solutions is performed.

Heat tolerance around flowering in wheat identified as a key trait for increased yield potential in Europe under climate change

PubMed Central

Stratonovitch, Pierre; Semenov, Mikhail A.

2015-01-01

To deliver food security for the 9 billon population in 2050, a 70% increase in world food supply will be required. Projected climatic and environmental changes emphasize the need for breeding strategies that delivers both a substantial increase in yield potential and resilience to extreme weather events such as heat waves, late frost, and drought. Heat stress around sensitive stages of wheat development has been identified as a possible threat to wheat production in Europe. However, no estimates have been made to assess yield losses due to increased frequency and magnitude of heat stress under climate change. Using existing experimental data, the Sirius wheat model was refined by incorporating the effects of extreme temperature during flowering and grain filling on accelerated leaf senescence, grain number, and grain weight. This allowed us, for the first time, to quantify yield losses resulting from heat stress under climate change. The model was used to optimize wheat ideotypes for CMIP5-based climate scenarios for 2050 at six sites in Europe with diverse climates. The yield potential for heat-tolerant ideotypes can be substantially increased in the future (e.g. by 80% at Seville, 100% at Debrecen) compared with the current cultivars by selecting an optimal combination of wheat traits, e.g. optimal phenology and extended duration of grain filling. However, at two sites, Seville and Debrecen, the grain yields of heat-sensitive ideotypes were substantially lower (by 54% and 16%) and more variable compared with heat-tolerant ideotypes, because the extended grain filling required for the increased yield potential was in conflict with episodes of high temperature during flowering and grain filling. Despite much earlier flowering at these sites, the risk of heat stress affecting yields of heat-sensitive ideotypes remained high. Therefore, heat tolerance in wheat is likely to become a key trait for increased yield potential and yield stability in southern Europe in the future. PMID:25750425

Self-monitored photothermal nanoparticles based on core-shell engineering

NASA Astrophysics Data System (ADS)

Ximendes, Erving C.; Rocha, Uéslen; Jacinto, Carlos; Kumar, Kagola Upendra; Bravo, David; López, Fernando J.; Rodríguez, Emma Martín; García-Solé, José; Jaque, Daniel

2016-01-01

The continuous development of nanotechnology has resulted in the actual possibility of the design and synthesis of nanostructured materials with pre-tailored functionabilities. Nanostructures capable of simultaneous heating and local thermal sensing are in strong demand as they would constitute a revolutionary solution to several challenging problems in bio-medicine, including the achievement of real time control during photothermal therapies. Several approaches have been demonstrated to achieve simultaneous heating and thermal sensing at the nanoscale. Some of them lack of sufficient thermal sensitivity and others require complicated synthesis procedures for heterostructure fabrication. In this study, we demonstrate how single core/shell dielectric nanoparticles with a highly Nd3+ ion doped shell and an Yb3+,Er3+ codoped core are capable of simultaneous thermal sensing and heating under an 808 nm single beam excitation. The spatial separation between the heating shell and sensing core provides remarkable values of the heating efficiency and thermal sensitivity, enabling their application in single beam-controlled heating experiments in both aqueous and tissue environments.

Sensitivity analysis for best-estimate thermal models of vertical dry cask storage systems

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

DeVoe, Remy R.; Robb, Kevin R.; Skutnik, Steven E.

Loading requirements for dry cask storage of spent nuclear fuel are driven primarily by decay heat capacity limitations, which themselves are determined through recommended limits on peak cladding temperature within the cask. This study examines the relative sensitivity of peak material temperatures within the cask to parameters that influence both the stored fuel residual decay heat as well as heat removal mechanisms. Here, these parameters include the detailed reactor operating history parameters (e.g., soluble boron concentrations and the presence of burnable poisons) as well as factors that influence heat removal, including non-dominant processes (such as conduction from the fuel basketmore » to the canister and radiation within the canister) and ambient environmental conditions. By examining the factors that drive heat removal from the cask alongside well-understood factors that drive decay heat, it is therefore possible to make a contextual analysis of the most important parameters to evaluation of peak material temperatures within the cask.« less

Sensitivity analysis for best-estimate thermal models of vertical dry cask storage systems

DOE PAGES

DeVoe, Remy R.; Robb, Kevin R.; Skutnik, Steven E.

2017-07-08

Loading requirements for dry cask storage of spent nuclear fuel are driven primarily by decay heat capacity limitations, which themselves are determined through recommended limits on peak cladding temperature within the cask. This study examines the relative sensitivity of peak material temperatures within the cask to parameters that influence both the stored fuel residual decay heat as well as heat removal mechanisms. Here, these parameters include the detailed reactor operating history parameters (e.g., soluble boron concentrations and the presence of burnable poisons) as well as factors that influence heat removal, including non-dominant processes (such as conduction from the fuel basketmore » to the canister and radiation within the canister) and ambient environmental conditions. By examining the factors that drive heat removal from the cask alongside well-understood factors that drive decay heat, it is therefore possible to make a contextual analysis of the most important parameters to evaluation of peak material temperatures within the cask.« less

Step-by-Step Heating of Dye Solution for Efficient Solar Energy Harvesting in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Shah, Syed Afaq Ali; Sayyad, Muhammad Hassan; Abdulkarim, Salem; Qiao, Qiquan

2018-05-01

A step-by-step heat treatment was applied to ruthenium-based N719 dye solution for its potential application in dye-sensitized solar cells (DSSCs). The effects were analyzed and compared with standard untreated devices. A significant increase in short circuit current density was observed by employing a step-by-step heating method for dye solution in DSSCs. This increase of J sc is attributed to the enhancement in dye adsorption by the surface of the semiconductor and the higher number of charge carriers generated. DSSCs fabricated by a heated dye solution have achieved an overall power conversion efficiency of 8.41% which is significantly higher than the efficiency of 7.31% achieved with DSSCs fabricated without heated dye. Electrochemical impedance spectroscopy and capacitance voltage studies were performed to understand the better performance of the device fabricated with heated dye. Furthermore, transient photocurrent and transient photovoltage measurements were also performed to gain an insight into interfacial charge carrier recombinations.

Self-actuated nuclear reactor shutdown system using induction pump to facilitate sensing of core coolant temperature

DOEpatents

Sievers, Robert K.; Cooper, Martin H.; Tupper, Robert B.

1987-01-01

A self-actuated shutdown system incorporated into a reactivity control assembly in a nuclear reactor includes pumping means for creating an auxiliary downward flow of a portion of the heated coolant exiting from the fuel assemblies disposed adjacent to the control assembly. The shutdown system includes a hollow tubular member which extends through the outlet of the control assembly top nozzle so as to define an outer annular flow channel through the top nozzle outlet separate from an inner flow channel for primary coolant flow through the control assembly. Also, a latching mechanism is disposed in an inner duct of the control assembly and is operable for holding absorber bundles in a raised position in the control assembly and for releasing them to drop them into the core of the reactor for shutdown purposes. The latching mechanism has an inner flow passage extending between and in flow communication with the absorber bundles and the inner flow channel of the top nozzle for accommodating primary coolant flow upwardly through the control assembly. Also, an outer flow passage separate from the inner flow passage extends through the latching mechanism between and in flow communication with the inner duct and the outer flow channel of the top nozzle for accommodating inflow of a portion of the heated coolant from the adjacent fuel assemblies. The latching mechanism contains a magnetic material sensitive to temperature and operable to cause mating or latching together of the components of the latching mechanism when the temperature sensed is below a known temperature and unmating or unlatching thereof when the temperature sensed is above a given temperature. The temperature sensitive magnetic material is positioned in communication with the heated coolant flow through the outer flow passage for directly sensing the temperature thereof. Finally, the pumping means includes a jet induction pump nozzle and diffuser disposed adjacent the bottom nozzle of the control assembly and in flow communication with the inlet thereof. The pump nozzle is operable to create an upward driving flow of primary coolant through the pump diffuser and then to the absorber bundles. The upward driving flow of primary coolant, in turn, creates a suction head within the outer flow channel of the top nozzle and thereby an auxiliary downward flow of the heated coolant portion exiting from the upper end of the adjacent fuel assemblies through the outer flow channel to the pump nozzle via the outer flow passage of the latching mechanism and an annular space between the outer and inner spaced ducts of the control assembly housing. The temperature of the heated coolant exiting from the adjacent fuel assemblies can thereby be sensed directly by the temperature sensitive magnetic material in the latching mechanism.

System for Cooling of Electronic Components

NASA Astrophysics Data System (ADS)

Vasil'ev, L. L.; Grakovich, L. P.; Dragun, L. A.; Zhuravlev, A. S.; Olekhnovich, V. A.; Rabetskii, M. I.

2017-01-01

Results of computational and experimental investigations of heat pipes having a predetermined thermal resistance and a system based on these pipes for air cooling of electronic components and diode assemblies of lasers are presented. An efficient compact cooling system comprising heat pipes with an evaporator having a capillary coating of a caked copper powder and a condenser having a developed outer finning, has been deviced. This system makes it possible to remove, to the ambient air, a heat flow of power more than 300 W at a temperature of 40-50°C.

A unique high heat flux facility for testing hypersonic engine components

NASA Technical Reports Server (NTRS)

Melis, Matthew E.; Gladden, Herbert J.

1990-01-01

This paper describes the Hot Gas Facility, a unique, reliable, and cost-effective high-heat-flux facility for testing hypersonic engine components developed at the NASA Lewis Research Center. The Hot Gas Facility is capable of providing heat fluxes ranging from 200 Btu/sq ft per sec on flat surfaces up to 8000 Btu/sq ft per sec at a leading edge stagnation point. The usefulness of the Hot Gas Facility for the NASP community was demonstrated by testing hydrogen-cooled structures over a range of temperatures and pressures. Ranges of the Reynolds numbers, Prandtl numbers, enthalpy, and heat fluxes similar to those expected during hypersonic flights were achieved.

Inhibition of heat-shock protein 90 sensitizes liver cancer stem-like cells to magnetic hyperthermia and enhances anti-tumor effect on hepatocellular carcinoma-burdened nude mice

PubMed Central

Yang, Rui; Tang, Qiusha; Miao, Fengqin; An, Yanli; Li, Mengfei; Han, Yong; Wang, Xihui; Wang, Juan; Liu, Peidang; Chen, Rong

2015-01-01

Purpose To explore the thermoresistance and expression of heat-shock protein 90 (HSP90) in magnetic hyperthermia-treated human liver cancer stem-like cells (LCSCs) and the effects of a heat-shock protein HSP90 inhibitor 17-allylamino-17-demethoxgeldanamycin (17-AAG) on hepatocellular carcinoma-burdened nude mice. Methods CD90+ LCSCs were isolated by magnetic-activated cell sorting from BEL-7404. Spheroid formation, proliferation, differentiation, drug resistance, and tumor formation assays were performed to identify stem cell characteristics. CD90-targeted thermosensitive magnetoliposomes (TMs)-encapsulated 17-AAG (CD90@17-AAG/TMs) was prepared by reverse-phase evaporation and its characteristics were studied. Heat tolerance in CD90+ LCSCs and the effect of CD90@17-AAG/TMs-mediated heat sensitivity were examined in vitro and in vivo. Results CD90+ LCSCs showed significant stem cell-like properties. The 17-AAG/TMs were successfully prepared and were spherical in shape with an average size of 128.9±7.7 nm. When exposed to magnetic hyperthermia, HSP90 was up-regulated in CD90+ LCSCs. CD90@17-AAG/TMs inhibited the activity of HSP90 and increased the sensitivity of CD90+ LCSCs to magnetic hyperthermia. Conclusion The inhibition of HSP90 could sensitize CD90+ LCSCs to magnetic hyperthermia and enhance its anti-tumor effects in vitro and in vivo. PMID:26677324

Comparative study on ambient ionization methods for direct analysis of navel orange tissues by mass spectrometry.

PubMed

Zhang, Hua; Bibi, Aisha; Lu, Haiyan; Han, Jing; Chen, Huanwen

2017-08-01

It is of sustainable interest to improve the sensitivity and selectivity of the ionization process, especially for direct analysis of complex samples without matrix separation. Herein, four ambient ionization methods including desorption atmospheric pressure chemical ionization (DAPCI), heat-assisted desorption atmospheric pressure chemical ionization (heat-assisted DAPCI), microwave plasma torch (MPT) and internal extractive electrospray ionization (iEESI) were employed for comparative analysis of the navel orange tissue samples by mass spectrometry. The volatile organic compounds (e.g. ethanol, vanillin, leaf alcohol and jasmine lactone) were successfully detected by non-heat-assisted DAPCI-MS, while semi-volatile organic compounds (e.g. 1-nonanol and ethyl nonanoate) together with low abundance of non-volatile organic compounds (e.g. sinensetin and nobiletin) were obtained by heat-assisted DAPCI-MS. Typical nonvolatile organic compounds [e.g. 5-(hydroxymethyl)furfural and glucosan] were sensitively detected with MPT-MS. Compounds of high polarity (e.g. amino acids, alkaloids and sugars) were easily profiled with iEESI-MS. Our data showed that more analytes could be detected when more energy was delivered for the desorption ionization purpose; however, heat-sensitive analytes would not be detected once the energy input exceeded the dissociation barriers of the analytes. For the later cases, soft ionization methods such as iEESI were recommended to sensitively profile the bioanalytes of high polarity. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

A sensitivity study of the effects of evaporation/condensation accommodation coefficients on transient heat pipe modeling

NASA Astrophysics Data System (ADS)

Hall, Michael L.; Doster, J. Michael

1990-03-01

The dynamic behavior of liquid metal heat pipe models is strongly influenced by the choice of evaporation and condensation modeling techniques. Classic kinetic theory descriptions of the evaporation and condensation processes are often inadequate for real situations; empirical accommodation coefficients are commonly utilized to reflect nonideal mass transfer rates. The complex geometries and flow fields found in proposed heat pipe systems cause considerable deviation from the classical models. the THROHPUT code, which has been described in previous works, was developed to model transient liquid metal heat pipe behavior from frozen startup conditions to steady state full power operation. It is used here to evaluate the sensitivity of transient liquid metal heat pipe models to the choice of evaporation and condensation accommodation coefficients. Comparisons are made with experimental liquid metal heat pipe data. It is found that heat pipe behavior can be predicted with the proper choice of the accommodation coefficients. However, the common assumption of spatially constant accommodation coefficients is found to be a limiting factor in the model.

Should You Have the Air Ducts in Your Home Cleaned?

EPA Pesticide Factsheets

2017-02-14

Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers heating and cooling coils.

Explicit approximations to estimate the perturbative diffusivity in the presence of convectivity and damping. I. Semi-infinite slab approximations

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

Berkel, M. van; Fellow of the Japan Society for the Promotion of Science; FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM- FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein

2014-11-15

In this paper, a number of new approximations are introduced to estimate the perturbative diffusivity (χ), convectivity (V), and damping (τ) in cylindrical geometry. For this purpose, the harmonic components of heat waves induced by localized deposition of modulated power are used. The approximations are based on semi-infinite slab approximations of the heat equation. The main result is the approximation of χ under the influence of V and τ based on the phase of two harmonics making the estimate less sensitive to calibration errors. To understand why the slab approximations can estimate χ well in cylindrical geometry, the relationships betweenmore » heat transport models in slab and cylindrical geometry are studied. In addition, the relationship between amplitude and phase with respect to their derivatives, used to estimate χ, is discussed. The results are presented in terms of the relative error for the different derived approximations for different values of frequency, transport coefficients, and dimensionless radius. The approximations show a significant region in which χ, V, and τ can be estimated well, but also regions in which the error is large. Also, it is shown that some compensation is necessary to estimate V and τ in a cylindrical geometry. On the other hand, errors resulting from the simplified assumptions are also discussed showing that estimating realistic values for V and τ based on infinite domains will be difficult in practice. This paper is the first part (Part I) of a series of three papers. In Part II and Part III, cylindrical approximations based directly on semi-infinite cylindrical domain (outward propagating heat pulses) and inward propagating heat pulses in a cylindrical domain, respectively, will be treated.« less

New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

NASA Technical Reports Server (NTRS)

Yamaguchi, Hiroya; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Petre, Robert; Slane, Patrick O.; Smith, Randall K.

2013-01-01

Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K beta (3p yields 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K alpha (2p yields 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K alpha morphology from the Chandra observations. Since strong Fe K beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

Temperature decline thermography for laminar-turbulent transition detection in aerodynamics

NASA Astrophysics Data System (ADS)

von Hoesslin, Stefan; Stadlbauer, Martin; Gruendmayer, Juergen; Kähler, Christian J.

2017-09-01

Detailed knowledge about laminar-turbulent transition and heat transfer distribution of flows around complex aerodynamic components are crucial to achieve highest efficiencies in modern aerodynamical systems. Several measurement techniques have been developed to determine those parameters either quantitatively or qualitatively. Most of them require extensive instrumentation or give unreliable results as the boundary conditions are often not known with the required precision. This work introduces the simple and robust temperature decline method to qualitatively detect the laminar-turbulent transition and the respective heat transfer coefficients on a surface exposed to an air flow, according to patent application Stadlbauer et al. (Patentnr. WO2014198251 A1, 2014). This method provides results which are less sensitive to control parameters such as the heat conduction into the blade material and temperature inhomogeneities in the flow or blade. This method was applied to measurements with NACA0018 airfoils exposed to the flow of a calibration-free jet at various Reynolds numbers and angles of attack. For data analysis, a post-processing method was developed and qualified to determine a quantity proportional to the heat transfer coefficient into the flow. By plotting this quantity for each pixel of the surface, a qualitative, two-dimensional heat transfer map was obtained. The results clearly depicted the areas of onset and end of transition over the full span of the model and agreed with the expected behavior based on the respective flow condition. To validate the approach, surface hotfilm measurements were conducted simultaneously on the same NACA profile. Both techniques showed excellent agreement. The temperature decline method allows to visualize laminar-turbulent transitions on static or moving parts and can be applied on a very broad range of scales—from tiny airfoils up to large airplane wings.

Second Harmonic Generation Mediated by Aligned Water in Starch Granules.

PubMed

Cisek, Richard; Tokarz, Danielle; Krouglov, Serguei; Steup, Martin; Emes, Michael J; Tetlow, Ian J; Barzda, Virginijus

2014-12-26

The origin of second harmonic generation (SHG) in starch granules was investigated using ab initio quantum mechanical modeling and experimentally examined using polarization-in, polarization-out (PIPO) second harmonic generation microscopy. Ab initio calculations revealed that the largest contribution to the SHG signal from A- and B-type allomorphs of starch originates from the anisotropic organization of hydroxide and hydrogen bonds mediated by aligned water found in the polymers. The hypothesis was experimentally tested by imaging maize starch granules under various hydration and heat treatment conditions that alter the hydrogen bond network. The highest SHG intensity was found in fully hydrated starch granules, and heat treatment diminished the SHG intensity. The PIPO SHG imaging showed that dried starch granules have a much higher nonlinear optical susceptibility component ratio than fully hydrated granules. In contrast, deuterated starch granules showed a smaller susceptibility component ratio demonstrating that SHG is highly sensitive to the organization of the hydroxyl and hydrogen bond network. The polarization SHG imaging results of potato starch granules, representing starch allomorph B, were compared to those of maize starch granules representing allomorph A. The results showed that the amount of aligned water was higher in the maize granules. Nonlinear microscopy of starch granules provides evidence that varying hydration conditions leads to significant changes in the nonlinear susceptibility ratio as well as the SHG intensity, supporting the hypothesis from ab initio calculations that the dominant contribution to SHG is due to the ordered hydroxide and hydrogen bond network.

Heat sensitization in skin and muscle nociceptors expressing distinct combinations of TRPV1 and TRPV2 protein.

PubMed

Rau, K K; Jiang, N; Johnson, R D; Cooper, B Y

2007-04-01

Recordings were made from small and medium diameter dorsal root ganglia (DRG) neurons that expressed transient receptor potential (TRP) proteins. Physiologically characterized skin nociceptors expressed either TRPV1 (type 2) or TRPV2 (type 4) in isolation. Other nociceptors co-expressed both TRP proteins and innervated deep tissue sites (gastrocnemius muscle, distal colon; type 5, type 8) and skin (type 8). Subpopulations of myelinated (type 8) and unmyelinated (type 5) nociceptors co-expressed both TRPs. Cells that expressed TRPV1 were excellent transducers of intense heat. Proportional inward currents were obtained from a threshold of approximately 46.5 to approximately 56 degrees C. In contrast, cells expressing TRPV2 alone (52 degrees C threshold) did not reliably transduce the intensity of thermal events. Studies were undertaken to assess the capacity of skin and deep nociceptors to exhibit sensitization to repeated intense thermal stimuli [heat-heat sensitization (HHS)]. Only nociceptors that expressed TRPV2, alone or in combination with TRPV1, exhibited HHS. HHS was shown to be Ca(2+) dependent in either case. Intracellular Ca(2+) dependent pathways to HHS varied with the pattern of TRP protein expression. Cells co-expressing both TRPs modulated heat reactivity through serine/threonine phosphorylation or PLA(2)-dependent pathways. Cells expressing only TRPV2 may have relied on tyrosine kinases for HHS. We conclude that heat sensitization in deep and superficial capsaicin and capsaicin-insensitive C and Adelta nociceptors varies with the distribution of TRPV1 and TRPV2 proteins. The expression pattern of these proteins are specific to subclasses of physiologically identified C and A fiber nociceptors with highly restricted tissue targets.

The mesoscale forcing of a midlatitude upper-tropospheric jet streak by a simulated convective system. 2: Kinetic energy and resolution analysis

NASA Technical Reports Server (NTRS)

Wolf, Bart J.; Johnson, D. R.

1995-01-01

A kinetic energy (KE) analysis of the forcing of a mesoscale upper-tropospheric jet streak by organized diabatic processes within the simulated convective system (SCS) that was discussed in Part 1 is presented in this study. The relative contributions of the ageostrophic components of motion to the generation of KE of the convectively generated jet streak are compared, along with the KE generation by the rotational (nondivergent) and irrotational (divergent) mass transport. The sensitivity of the numerical simulations of SCS development to resolution is also briefly examined. Analysis within isentropic coordinates provides for an explicit determination of the influence of the diabatic processes on the generation of KE. The upper-level production of specific KE is due predominatly to the inertial advective ageostrophic component (IAD), and as such represents the primary process through which the KE of the convectively generated jet streak is realized. A secondary contribution by the inertial diabatic (IDI) term is observed. Partitioning the KE generation into its rotational and irrotational components reveals that the latter, which is directly linked to the diabatic heating within the SCS through isentropic continuity requirements, is the ultimate source of KE generation as the global area integral of generation by the rotational component vanishes. Comparison with an identical dry simulation reveals that the net generation of KE must be attributed to latent heating. Both the IAD and IDI ageostrophic components play important roles in this regard. Examination of results from simulations conducted at several resolutions supports the previous findings in that the effects of diabatic processes and ageostrophic motion on KE generation remain consistent. Resolution does impact the location and timing of SCS development, a result that has important implications in forecasting the onset of convection that develops from evolution of the large-scale flow and moisture transport. Marked differences are observed in the momentum field aloft subsequent to the life cycle of the SCS in the 1 deg, 30-level base case (MP130) simulation discussed in Part 1 versus its 2 deg counterparts in that the MP130 simulation with higher spatial resolution contains from 14% to 30% more total KE.

Insights into the Molecular Events That Regulate Heat-Induced Chilling Tolerance in Citrus Fruits.

PubMed

Lafuente, María T; Establés-Ortíz, Beatriz; González-Candelas, Luis

2017-01-01

Low non-freezing temperature may cause chilling injury (CI), which is responsible for external quality deterioration in many chilling-sensitive horticultural crops. Exposure of chilling-sensitive citrus cultivars to non-lethal high-temperature conditioning may increase their chilling tolerance. Very little information is available about the molecular events involved in such tolerance. In this work, the molecular events associated with the low temperature tolerance induced by heating Fortune mandarin, which is very sensitive to chilling, for 3 days at 37°C prior to cold storage is presented. A transcriptomic analysis reveals that heat-conditioning has an important impact favoring the repression of genes in cold-stored fruit, and that long-term heat-induced chilling tolerance is an active process that requires activation of transcription factors involved in transcription initiation and of the WRKY family. The analysis also shows that chilling favors degradation processes, which affect lipids and proteins, and that the protective effect of the heat-conditioning treatment is more likely to be related to the repression of the genes involved in lipid degradation than to the modification of fatty acids unsaturation, which affects membrane permeability. Another major factor associated with the beneficial effect of the heat treatment on reducing CI is the regulation of stress-related proteins. Many of the genes that encoded such proteins are involved in secondary metabolism and in oxidative stress-related processes.

WE-AB-BRB-01: Development of a Probe-Format Graphite Calorimeter for Practical Clinical Dosimetry: Numerical Design Optimization, Prototyping, and Experimental Proof-Of-Concept

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

Renaud, J; Seuntjens, J; Sarfehnia, A

2015-06-15

Purpose: In this work, the feasibility of performing absolute dose to water measurements using a constant temperature graphite probe calorimeter (GPC) in a clinical environment is established. Methods: A numerical design optimization study was conducted by simulating the heat transfer in the GPC resulting from irradiation using a finite element method software package. The choice of device shape, dimensions, and materials was made to minimize the heat loss in the sensitive volume of the GPC. The resulting design, which incorporates a novel aerogel-based thermal insulator, and 15 temperature sensitive resistors capable of both Joule heating and measuring temperature, was constructedmore » in house. A software based process controller was developed to stabilize the temperatures of the GPC’s constituent graphite components to within a few 10’s of µK. This control system enables the GPC to operate in either the quasi-adiabatic or isothermal mode, two well-known, and independent calorimetry techniques. Absorbed dose to water measurements were made using these two methods under standard conditions in a 6 MV 1000 MU/min photon beam and subsequently compared against TG-51 derived values. Results: Compared to an expected dose to water of 76.9 cGy/100 MU, the average GPC-measured doses were 76.5 ± 0.5 and 76.9 ± 0.5 cGy/100 MU for the adiabatic and isothermal modes, respectively. The Monte Carlo calculated graphite to water dose conversion was 1.013, and the adiabatic heat loss correction was 1.003. With an overall uncertainty of about 1%, the most significant contributions were the specific heat capacity (type B, 0.8%) and the repeatability (type A, 0.6%). Conclusion: While the quasi-adiabatic mode of operation had been validated in previous work, this is the first time that the GPC has been successfully used isothermally. This proof-of-concept will serve as the basis for further study into the GPC’s application to small fields and MRI-linac dosimetry. This work has been supported in part by the CREATE Medical Physics Research Training Network of the Natural Sciences and Engineering Research Council (NSERC) grant 432290, NSERC grants RGPIN 298191 & 435608-13, Canadian Institutes of Health Research doctoral scholarship GSD-121793. This work has also been supported by Sun Nuclear Corporation.« less

High-Performance Computing Data Center | Computational Science | NREL

Science.gov Websites

liquid cooling to achieve its very low PUE, then captures and reuses waste heat as the primary heating dry cooler that uses refrigerant in a passive cycle to dissipate heat-is reducing onsite water Measuring efficiency through PUE Warm-water liquid cooling Re-using waste heat from computing components

Solar Schematic

NASA Technical Reports Server (NTRS)

1979-01-01

The home shown at right is specially designed to accommodate solar heating units; it has roof planes in four directions, allowing placement of solar collectors for best exposure to the sun. Plans (bottom) and complete working blueprints for the solar-heated house are being marketed by Home Building Plan Service, Portland, Oregon. The company also offers an inexpensive schematic (center) showing how a homeowner only moderately skilled in the use of tools can build his own solar energy system, applicable to new or existing structures. The schematic is based upon the design of a low-cost solar home heating system built and tested by NASA's Langley Research Center; used to supplement a warm-air heating system, it can save the homeowner about 40 percent of his annual heating bill for a modest investment in materials and components. Home Building Plan Service saved considerable research time by obtaining a NASA technical report which details the Langley work. The resulting schematic includes construction plans and simplified explanations of solar heat collection, collectors and other components, passive heat factors, domestic hot water supply and how to work with local heating engineers.

On the origin of X-ray spectra in luminous blazars

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

Sikora, Marek; Janiak, Mateusz; Nalewajko, Krzysztof

2013-11-26

Gamma-ray luminosities of some quasar-associated blazars imply jet powers reaching values comparable to the accretion power even if assuming very strong Doppler boosting and very high efficiency of gamma-ray production. With much lower radiative efficiencies of protons than of electrons, and the recent reports of very strong coupling of electrons with shock-heated protons indicated by particle-in-cell simulations, the leptonic models seem to be strongly favored over the hadronic ones. However, the electron-proton coupling combined with the external-radiation-Compton (ERC) models of gamma-ray production in leptonic models predict extremely hard X-ray spectra, with energy indices α x ~ 0. This is inconsistentmore » with the observed 2-10 keV slopes of blazars, which cluster around α x ~ 0.6. This problem can be resolved by assuming that electrons can be efficiently cooled down radiatively to non-relativistic energies, or that blazar spectra are entirely dominated by the synchrotron self-Compton (SSC) component up to at least 10 keV. Here, we show that the required cooling can be sufficiently efficient only at distances r < 0.03 pc. SSC spectra, on the other hand, can be produced roughly co-spatially with the observed synchrotron and ERC components, which are most likely located roughly at a parsec scale. We show that the dominant SSC component can also be produced much further than the dominant synchrotron and ERC components, at distances of gsim 10 pc. Hence, depending on the spatial distribution of the energy dissipation along the jet, one may expect to see γ-ray/optical events with either correlated or uncorrelated X-rays. In all cases the number of e +e – pairs per proton is predicted to be very low. The direct verification of the proposed SSC scenario, and particularly the question of the co-spatiality of the SSC component with other spectral components, requires sensitive observations in the hard X-ray band. Lastly, this is now possible with the deployment of the NuSTAR satellite, providing the required sensitivity to monitor the details of the hard X-ray spectra of blazars in the range where the ERC component is predicted to start dominating over the SSC component.« less

Deficiency in endogenous modulation of prolonged heat pain in patients with Irritable Bowel Syndrome and Temporomandibular Disorder

PubMed Central

King, Christopher D.; Wong, Fong; Currie, Tom; Mauderli, Andre P.; Fillingim, Roger B.; Riley, Joseph L.

2013-01-01

Females with Irritable Bowel Syndrome (IBS) and Temporomandibular Disorder (TMD) are characterized by enhanced sensitivity to experimental pain. One possible explanation for this observation is deficiencies in pain modulation systems like Diffuse Noxious Inhibitory Control (DNIC). In a few studies that used brief stimuli, chronic pain patients demonstrate reduced DNIC. The purpose of this study was to compare sensitivity to prolonged heat pain and the efficacy of DNIC in controls to IBS and TMD patients. Heat pain (experimental stimulus; 44.0-49.0°C), which was applied to left palm, was continuously rated during three 30-second trials across three separate testing sessions under the following conditions: without a conditioning stimulus; during concurrent immersion of the right foot in a 23.0°C (control); and during noxious cold immersion in a (DNIC; 8.0-16.0°C) water bath. Compared to controls, IBS and TMD patients reported increased sensitivity to heat pain and failed to demonstrate pain inhibition due to DNIC. Controls showed a significant reduction in pain during the DNIC session. These findings support the idea that chronic pain patients are not only more pain sensitive and demonstrate reduced pain inhibition by pain, possibly because of dysfunction of endogenous pain inhibition systems. PMID:19278784

Sensitivity of Austempering Heat Treatment of Ductile Irons to Changes in Process Parameters

NASA Astrophysics Data System (ADS)

Boccardo, A. D.; Dardati, P. M.; Godoy, L. A.; Celentano, D. J.

2018-06-01

Austempered ductile iron (ADI) is frequently obtained by means of a three-step austempering heat treatment. The parameters of this process play a crucial role on the microstructure of the final product. This paper considers the influence of some process parameters ( i.e., the initial microstructure of ductile iron and the thermal cycle) on key features of the heat treatment (such as minimum required time for austenitization and austempering and microstructure of the final product). A computational simulation of the austempering heat treatment is reported in this work, which accounts for a coupled thermo-metallurgical behavior in terms of the evolution of temperature at the scale of the part being investigated (the macroscale) and the evolution of phases at the scale of microconstituents (the microscale). The paper focuses on the sensitivity of the process by looking at a sensitivity index and scatter plots. The sensitivity indices are determined by using a technique based on the variance of the output. The results of this study indicate that both the initial microstructure and the thermal cycle parameters play a key role in the production of ADI. This work also provides a guideline to help selecting values of the appropriate process parameters to obtain parts with a required microstructural characteristic.

Human immunodeficiency virus type 1 RNA in breast-milk components.

PubMed

Hoffman, Irving F; Martinson, Francis E A; Stewart, Paul W; Chilongozi, David A; Leu, Szu-Yun; Kazembe, Peter N; Banda, Topia; Dzinyemba, Willard; Joshi, Priya; Cohen, Myron S; Fiscus, Susan A

2003-10-15

We conducted the present study to determine which of the 4 components of breast milk (whole milk, skim milk, lipid layer, and breast-milk cells) had the highest sensitivity and concentration of human immunodeficiency virus (HIV) type 1 RNA burden and to determine biological correlates to these factors. The probability of detection of HIV (sensitivity) and the concentration of HIV-1 RNA were both associated with the choice of milk component, CD4(+) cell count, concentration of blood serum HIV-1 RNA, and the presence of breast inflammation. Whole milk demonstrated higher sensitivity and mean concentration than any other single component. Sensitivity was enhanced by analyzing all 4 components of breast milk.

Genetic effects of heat stress on milk yield of Thai Holstein crossbreds.

PubMed

Boonkum, W; Misztal, I; Duangjinda, M; Pattarajinda, V; Tumwasorn, S; Sanpote, J

2011-01-01

The threshold for heat stress on milk yield of Holstein crossbreds under climatic conditions in Thailand was investigated, and genetic effects of heat stress on milk yield were estimated. Data included 400,738 test-day milk yield records for the first 3 parities from 25,609 Thai crossbred Holsteins between 1990 and 2008. Mean test-day milk yield ranged from 12.6 kg for cows with <87.5% Holstein genetics to 14.4 kg for cows with ≥93.7% Holstein genetics. Daily temperature and humidity data from 26 provincial weather stations were used to calculate a temperature-humidity index (THI). Test-day milk yield varied little with THI for first parity except above a THI of 82 for cows with ≥93.7% Holstein genetics. For third parity, test-day milk yield started to decline after a THI of 74 for cows with ≥87.5% Holstein genetics and declined more rapidly after a THI of 82. A repeatability test-day model with parities as correlated traits was used to estimate heat stress parameters; fixed effects included herd-test month-test year and breed groups, days in milk, calving age, and parity; random effects included 2 additive genetic effects, regular and heat stress, and 2 permanent environment, regular and heat stress. The threshold for effect of heat stress on test-day milk yield was set to a THI of 80. All variance component estimates increased with parity; the largest increases were found for effects associated with heat stress. In particular, genetic variance associated with heat stress quadrupled from first to third parity, whereas permanent environmental variance only doubled. However, permanent environmental variance for heat stress was at least 10 times larger than genetic variance. Genetic correlations among parities for additive effects without heat stress considered ranged from 0.88 to 0.96. Genetic correlations among parities for additive effects of heat stress ranged from 0.08 to 0.22, and genetic correlations between effects regular and heat stress effects ranged from -0.21 to -0.33 for individual parities. Effect of heat stress on Thai Holstein crossbreds increased greatly with parity and was especially large after a THI of 80 for cows with a high percentage of Holstein genetics (≥93.7%). Individual sensitivity to heat stress was more environmental than genetic for Thai Holstein crossbreds. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Seed nutrition and quality, seed coat boron and lignin are influenced by delayed harvest in exotically-derived soybean breeding lines under high heat

USDA-ARS?s Scientific Manuscript database

Growing heat sensitive soybean under the high heat and humid environment of the Early Soybean Production System (ESPS) in the Midsouthern USA often leads to poor seed quality. Therefore, breeding for heat tolerant soybeans that maintain high quality of seed nutrition, high germination, and high prot...

Sustained and Transient Contributions to the Rat Dark-Adapted Electroretinogram b-Wave

PubMed Central

Dang, Trung M.; Vingrys, Algis J.; Bui, Bang V.

2013-01-01

The most dominant feature of the electroretinogram, the b-wave, is thought to reflect ON-bipolar cell responses. However, a number of studies suggest that the b-wave is made up of several components. We consider the composition of the rat b-wave by subtracting corneal negative components obtained using intravitreal application of pharmacological agents to remove postreceptoral responses. By analyzing the intensity-response characteristic of the PII across a range of fixed times during and after a light step, we find that the rat isolated PII has 2 components. The first has fast rise and decay characteristics with a low sensitivity to light. GABAc-mediated inhibitory pathways enhance this transient-ON component to manifest increased and deceased sensitivity to light at shorter (<160 ms) and longer times, respectively. The second component has slower temporal characteristics but is more sensitive to light. GABAc-mediated inhibition enhances this sustained-ON component but has little effect on its sensitivity to light. After stimulus offset, both transient and sustained components return to baseline, and a long latency sustained positive component becomes apparent. The light sensitivities of transient-ON and sustained-OFF components are consistent with activity arising from cone ON- and OFF-bipolar cells, whereas the sustained-ON component is likely to arise from rod bipolar cells. PMID:23533706

Microwave and micronization treatments affect dehulling characteristics and bioactive contents of dry beans (Phaseolus vulgaris L.).

PubMed

Oomah, B Dave; Kotzeva, Lily; Allen, Meghan; Bassinello, Priscila Zaczuk

2014-05-01

Heat pretreatment is considered the first step in grain milling. This study therefore evaluated microwave and micronization heat treatments in improving the dehulling characteristics, phenolic composition and antioxidant and α-amylase activities of bean cultivars from three market classes. Heat treatments improved dehulling characteristics (hull yield, rate coefficient and reduced abrasive hardness index) depending on bean cultivar, whereas treatment effects increased with dehulling time. Micronization increased minor phenolic components (tartaric esters, flavonols and anthocyanins) of all beans but had variable effects on total phenolic content depending on market class. Microwave treatment increased α-amylase inhibitor concentration, activity and potency, which were strongly correlated (r²  = 0.71, P < 0.0001) with the flavonol content of beans. Heat treatment had variable effects on the phenolic composition of bean hulls obtained by abrasive dehulling without significantly altering the antioxidant activity of black and pinto bean hulls. Principal component analysis on 22 constituents analyzed in this study demonstrated the differences in dehulling characteristics and phenolic components of beans and hulls as major factors in segregating the beneficial heat treatment effects. Heat treatment may be useful in developing novel dietary fibers from beans with variable composition and bioactivity with a considerable range of applications as functional food ingredients. © 2013 Society of Chemical Industry.

Sensitivity analysis on the performances of a closed-loop Ground Source Heat Pump

NASA Astrophysics Data System (ADS)

Casasso, Alessandro; Sethi, Rajandrea

2014-05-01

Ground Source Heat Pumps (GSHP) permit to achieve a significant reduction of greenhouse gas emissions, and the margins for economic saving of this technology are strongly correlated to the long-term sustainability of the exploitation of the heat stored in the soil. The operation of a GSHP over its lifetime should be therefore modelled considering realistic conditions, and a thorough characterization of the physical properties of the soil is essential to avoid large errors of prediction. In this work, a BHE modelling procedure with the finite-element code FEFLOW is presented. Starting from the governing equations of the heat transport in the soil around a GSHP and inside the BHE, the most important parameters are individuated and the adopted program settings are explained. A sensitivity analysis is then carried on both the design parameters of the heat exchanger, in order to understand the margins of improvement of a careful design and installation, and the physical properties of the soil, with the aim of quantifying the uncertainty induced by their variability. The relative importance of each parameter is therefore assessed by comparing the statistical distributions of the fluid temperatures and estimating the energy consumption of the heat pump, and practical conclusions are from these results about the site characterization, the design and the installation of a BHE. References Casasso A., Sethi R., 2014 Efficiency of closed loop geothermal heat pumps: A sensitivity analysis, Renewable Energy 62 (2014), pp. 737-746 Chiasson A.C., Rees S.J., Spitler J.D., 2000, A preliminary assessment of the effects of groundwater flow on closed-loop ground-source heat pump systems, ASHRAE Transactions 106 (2000), pp. 380-393 Delaleux F., Py X., Olives R., Dominguez A., 2012, Enhancement of geothermal borehole heat exchangers performances by improvement of bentonite grouts conductivity, Applied Thermal Engineering 33-34, pp. 92-99 Diao N., Li Q., Fang Z., 2004, Heat transfer in ground heat exchangers with groundwater advection, International Journal of Thermal Sciences 43, pp. 1203-1211 Michopoulos A., Kyriakis N., 2010, The influence of a vertical ground heat exchanger length on the electricity consumption of the heat pumps, Renewable Energy 35 (2010), pp. 1403-1407

Effects of Transcutaneous Electrical Nerve Stimulation on Pain, Pain Sensitivity, and Function in People With Knee Osteoarthritis: A Randomized Controlled Trial

PubMed Central

Vance, Carol Grace T.; Rakel, Barbara A.; Blodgett, Nicole P.; DeSantana, Josimari Melo; Amendola, Annunziato; Zimmerman, Miriam Bridget; Walsh, Deirdre M.

2012-01-01

Background Transcutaneous electrical nerve stimulation (TENS) is commonly used for the management of pain; however, its effects on several pain and function measures are unclear. Objective The purpose of this study was to determine the effects of high-frequency TENS (HF-TENS) and low-frequency TENS (LF-TENS) on several outcome measures (pain at rest, movement-evoked pain, and pain sensitivity) in people with knee osteoarthritis. Design The study was a double-blind, randomized clinical trial. Setting The setting was a tertiary care center. Participants Seventy-five participants with knee osteoarthritis (29 men and 46 women; 31–94 years of age) were assessed. Intervention Participants were randomly assigned to receive HF-TENS (100 Hz) (n=25), LF-TENS (4 Hz) (n=25), or placebo TENS (n=25) (pulse duration=100 microseconds; intensity=10% below motor threshold). Measurements The following measures were assessed before and after a single TENS treatment: cutaneous mechanical pain threshold, pressure pain threshold (PPT), heat pain threshold, heat temporal summation, Timed “Up & Go” Test (TUG), and pain intensity at rest and during the TUG. A linear mixed-model analysis of variance was used to compare differences before and after TENS and among groups (HF-TENS, LF-TENS, and placebo TENS). Results Compared with placebo TENS, HF-TENS and LF-TENS increased PPT at the knee; HF-TENS also increased PPT over the tibialis anterior muscle. There was no effect on the cutaneous mechanical pain threshold, heat pain threshold, or heat temporal summation. Pain at rest and during the TUG was significantly reduced by HF-TENS, LF-TENS, and placebo TENS. Limitations This study tested only a single TENS treatment. Conclusions Both HF-TENS and LF-TENS increased PPT in people with knee osteoarthritis; placebo TENS had no significant effect on PPT. Cutaneous pain measures were unaffected by TENS. Subjective pain ratings at rest and during movement were similarly reduced by active TENS and placebo TENS, suggesting a strong placebo component of the effect of TENS. PMID:22466027

Differential heating: A versatile method for thermal conductivity measurements in high-energy-density matter

DOE PAGES

Ping, Y.; Fernandez-Panella, A.; Sio, H.; ...

2015-09-04

We propose a method for thermal conductivity measurements of high energy density matter based on differential heating. A temperature gradient is created either by surface heating of one material or at an interface between two materials by different energy deposition. The subsequent heat conduction across the temperature gradient is observed by various time-resolved probing techniques. Conceptual designs of such measurements using laser heating, proton heating, and x-ray heating are presented. As a result, the sensitivity of the measurements to thermal conductivity is confirmed by simulations.

Practical Considerations for Optimizing Position Sensitivity in Arrays of Position-sensitive TES's

NASA Technical Reports Server (NTRS)

Smith, Stephen J.; Bandler, Simon R.; Figueroa-Feliciano, Encetali; Iyomoto, Naoko; Kelley, Richard L.; Kilbourne, Caroline A.; Porder, Frederick S.; Sadleir, John E.

2007-01-01

We are developing Position-Sensitive Transitions-Edge Sensors (PoST's) for future X-ray astronomy missions such as NASA's Constellation-X. The PoST consists of one or more Transitions Edge Sensors (TES's) thermally connected to a large X-ray absorber, which through heat diffusion, gives rise to position dependence. The development of PoST's is motivated by the desire to achieve the largest the focal-plan coverage with the fewest number of readout channels. In order to develop a practical array, consisting of an inner pixellated core with an outer array of large absorber PoST's, we must be able to simultaneously read out all (-1800) channels in the array. This is achievable using time division multiplexing (TDM), but does set stringent slew rate requirements on the array. Typically, we must damp the pulses to reduce the slew rate of the input signal to the TDM. This is achieved by applying a low-pass analog filter with large inductance to the signal. This attenuates the high frequency components of the signal, essential for position discrimination in PoST's, relative to the white noise of the readout chain and degrades the position sensitivity. Using numerically simulated data, we investigate the position sensing ability of typical PoST designs under such high inductance conditions. We investigate signal-processing techniques for optimal determination of the event position and discuss the practical considerations for real-time implementation.

Transcript analysis in two alfalfa salt tolerance selected breeding populations relative to a non-tolerant population.

PubMed

Gruber, M Y; Xia, J; Yu, M; Steppuhn, H; Wall, K; Messer, D; Sharpe, A G; Acharya, S N; Wishart, D S; Johnson, D; Miller, D R; Taheri, A

2017-02-01

With the growing limitations on arable land, alfalfa (a widely cultivated, low-input forage) is now being selected to extend cultivation into saline lands for low-cost biofeedstock purposes. Here, minerals and transcriptome profiles were compared between two new salinity-tolerant North American alfalfa breeding populations and a more salinity-sensitive western Canadian alfalfa population grown under hydroponic saline conditions. All three populations accumulated two-fold higher sodium in roots than shoots as a function of increased electrical conductivity. At least 50% of differentially expressed genes (p < 0.05) were down-regulated in the salt-sensitive population growing under high salinity, while expression remained unchanged in the saline-tolerant populations. In particular, most reduction in transcript levels in the salt-sensitive population was observed in genes specifying cell wall structural components, lipids, secondary metabolism, auxin and ethylene hormones, development, transport, signalling, heat shock, proteolysis, pathogenesis-response, abiotic stress, RNA processing, and protein metabolism. Transcript diversity for transcription factors, protein modification, and protein degradation genes was also more strongly affected in salt-tolerant CW064027 than in salt-tolerant Bridgeview and salt-sensitive Rangelander, while both saline-tolerant populations showed more substantial up-regulation in redox-related genes and B-ZIP transcripts. The report highlights the first use of bulked genotypes as replicated samples to compare the transcriptomes of obligate out-cross breeding populations in alfalfa.

Assessment of the Sensitizing Potential of Processed Peanut Proteins in Brown Norway Rats: Roasting Does Not Enhance Allergenicity

PubMed Central

Kroghsbo, Stine; Rigby, Neil M.; Johnson, Philip E.; Adel-Patient, Karine; Bøgh, Katrine L.; Salt, Louise J.; Mills, E. N. Clare; Madsen, Charlotte B.

2014-01-01

Background IgE-binding of process-modified foods or proteins is the most common method for examination of how food processing affects allergenicity of food allergens. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix. Objectives The aim was to investigate if thermal processing increases sensitization potential of whole peanuts via the oral route. In parallel, the effect of heating on sensitization potential of the major peanut allergen Ara h 1 was assessed via the intraperitoneal route. Methods Sensitization potential of processed peanut products and Ara h 1 was examined in Brown Norway (BN) rats by oral administration of blanched or oil-roasted peanuts or peanut butter or by intraperitoneal immunization of purified native (N-), heated (H-) or heat glycated (G-)Ara h 1. Levels of specific IgG and IgE were determined by ELISA and IgE functionality was examined by rat basophilic leukemia (RBL) cell assay. Results In rats dosed orally, roasted peanuts induced significant higher levels of specific IgE to NAra h 1 and 2 than blanched peanuts or peanut butter but with the lowest level of RBL degranulation. However, extract from roasted peanuts was found to be a superior elicitor of RBL degranulation. Process-modified Ara h 1 had similar sensitizing capacity as NAra h 1 but specific IgE reacted more readily with process-modified Ara h 1 than with native. Conclusions Peanut products induce functional specific IgE when dosed orally to BN rats. Roasted peanuts do not have a higher sensitizing capacity than blanched peanuts. In spite of this, extract from roasted peanuts is a superior elicitor of RBL cell degranulation irrespectively of the peanut product used for sensitization. The results also suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose. PMID:24805813

THERMAL DESIGN OF THE ITER VACUUM VESSEL COOLING SYSTEM

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

Carbajo, Juan J; Yoder Jr, Graydon L; Kim, Seokho H

RELAP5-3D models of the ITER Vacuum Vessel (VV) Primary Heat Transfer System (PHTS) have been developed. The design of the cooling system is described in detail, and RELAP5 results are presented. Two parallel pump/heat exchanger trains comprise the design one train is for full-power operation and the other is for emergency operation or operation at decay heat levels. All the components are located inside the Tokamak building (a significant change from the original configurations). The results presented include operation at full power, decay heat operation, and baking operation. The RELAP5-3D results confirm that the design can operate satisfactorily during bothmore » normal pulsed power operation and decay heat operation. All the temperatures in the coolant and in the different system components are maintained within acceptable operating limits.« less

Heat transfer in condensing and evaporating two-component, two-phase flow inside a horizontal tube

NASA Astrophysics Data System (ADS)

Duval, W. M. B.

The effect of adding a small amount of oil to condensing and evaporation refrigerant R-12 following inside a horizontal tube is investigated both experimentally and analytically. Analytically, the problem is addressed assuming annular flow inside the tube. The analysis is based on the momentum and energy equations with the heat transfer in the liquid film determined using the Reynolds analogy between turbulent heat and momentum transfer. Two separate methods are developed for extending this model to include the effects of the two-component nature of the flow. Experimentally, two-phase local heat transfer measurements and flow pattern visualization are made for both condensation and evaporation. From the measurements, correlations are developed to predict two-phase heat transfer for the range of 0%, 2% and 5% oil fraction by mass flow.

Heat Shielding Characteristics and Thermostructural Performance of a Superalloy Honeycomb Sandwich Thermal Protection System (TPS)

NASA Technical Reports Server (NTRS)

Ko, William L.

2004-01-01

Heat-transfer, thermal bending, and mechanical buckling analyses have been performed on a superalloy "honeycomb" thermal protection system (TPS) for future hypersonic flight vehicles. The studies focus on the effect of honeycomb cell geometry on the TPS heat-shielding performance, honeycomb cell wall buckling characteristics, and the effect of boundary conditions on the TPS thermal bending behavior. The results of the study show that the heat-shielding performance of a TPS panel is very sensitive to change in honeycomb core depth, but insensitive to change in honeycomb cell cross-sectional shape. The thermal deformations and thermal stresses in the TPS panel are found to be very sensitive to the edge support conditions. Slight corrugation of the honeycomb cell walls can greatly increase their buckling strength.

Membrane oxygenator heat exchanger failure detected by unique blood gas findings.

PubMed

Hawkins, Justin L

2014-03-01

Failure of components integrated into the cardiopulmonary bypass circuit, although rare, can bring about catastrophic results. One of these components is the heat exchanger of the membrane oxygenator. In this compartment, unsterile water from the heater cooler device is separated from the sterile blood by stainless steel, aluminum, or by polyurethane. These areas are glued or welded to keep the two compartments separate, maintaining sterility of the blood. Although quality control testing is performed by the manufacturer at the factory level, transport presents the real possibility for damage. Because of this, each manufacturer has included in the instructions for use a testing procedure for testing the integrity of the heat exchanger component. Water is circulated through the heat exchanger before priming and a visible check is made of the oxygenator bundle to check for leaks. If none are apparent, then priming of the oxygenator is performed. In this particular case, this procedure was not useful in detecting communication between the water and blood chambers of the oxygenator.

The Effect of Heat Treatment on the Sensitized Corrosion of the 5383-H116 Al-Mg Alloy

PubMed Central

Lin, Ying-Kai; Wang, Shing-Hai; Chen, Ren-Yu; Hsieh, Tso-Sheng; Tsai, Liren; Chiang, Chia-Chin

2017-01-01

In this study, the effects of heat treatment and sensitized corrosion on the 5383-H116 Al-Mg alloy were investigated for temperatures ranging from 100 to 450 °C. The results show that the heat treatment temperature is the main factor that causes changes to the microstructure and mechanical strength of the 5383-H116 Al-Mg alloy, inducing β-phase (Al3Mg2) precipitation in the form of a continuous layer along the grain boundaries. Intergranular corrosion was caused by the β-phase of the grain boundary precipitation, and the corrosion susceptibility of the recrystallized structure was significantly higher than the corrosion susceptibility of the recovered structure. According to the conductivity values detected, β-phase precipitation can enhance the 5383-H116 Al-Mg alloy conductivity, with the response due to structural dislocation density being higher than that due to the recrystallized structure. As such, the β-phase precipitation after sensitization is more significant than the β-phase precipitation prior to the sensitization, such that after sensitization, the conductivity rises to a significantly higher level than that exhibited by the recrystallization structure. PMID:28772635

Solar industrial process heat systems: An assessment of standards for materials and components

NASA Astrophysics Data System (ADS)

Rossiter, W. J.; Shipp, W. E.

1981-09-01

A study was conducted to obtain information on the performance of materials and components in operational solar industrial process heat (PH) systems, and to provide recommendations for the development of standards including evaluative test procedures for materials and components. An assessment of the needs for standards for evaluating the long-term performance of materials and components of IPH systems was made. The assessment was based on the availability of existing standards, and information obtained from a field survey of operational systems, the literature, and discussions with individuals in the industry. Field inspections of 10 operational IPH systems were performed.

Coolant and ambient temperature control for chillerless liquid cooled data centers

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Simons, Robert E.

2017-08-29

Cooling control methods and systems include measuring a temperature of air provided to one or more nodes by an air-to-liquid heat exchanger; measuring a temperature of at least one component of the one or more nodes and finding a maximum component temperature across all such nodes; comparing the maximum component temperature to a first and second component threshold and comparing the air temperature to a first and second air threshold; and controlling a proportion of coolant flow and a coolant flow rate to the air-to-liquid heat exchanger and the one or more nodes based on the comparisons.

An Innovative Very Low Thermal Power Waste Heat Recovery System for Thermal Control of Deep Space Missions: A Thermal Flask in Space

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep

2015-01-01

Future missions to deep space, such as those to the outer planets (Jupiter, Saturn, etc.), which would rely on solar photovoltaic power, would need extremely large solar arrays to produce sufficient power for their operations because solar intensity is so low at those locations. Hence any additional power that would be needed for thermal control is extremely limited. Previous deep space missions like Juno (to Jupiter) required almost 200 W of electrical power for thermal control. This is prohibitively large for many future mission concepts, and leads to them needing very large solar arrays. For Saturn, where the solar flux is 1/4th the flux at Jupiter, this would entail an extremely large increase in the solar array size to accommodate the need for thermal survival power, which would be prohibitively large in size and mass, and very expensive. Hence there is a need to come up with a thermal architecture and design options that would not need such prohibitively large thermal power levels. One solution relies on harvesting the pre-existing waste heat from all the heat dissipation that would be present from operation of electronics, instruments, etc. for their own functionality. For example, for a generic Saturn mission, the various electronics would already dissipate about 200 Watts of heat that is simply "thrown away" to space from the spacecraft surfaces. The amount of thermal power that would be required for the safe thermal control of components within the spacecraft in deep space would be roughly of this magnitude for this class of spacecraft. So it makes good sense to try to harvest the waste heat and employ it to maintain the temperatures of all the components within their allowable limits. In particular, propulsion systems typically need to be kept above their freezing limits, around room temperature (15 C). Electronics needs to be kept typically above -40 C and batteries above -20 C. The next question becomes how to harvest this waste heat and direct it to the components that would need it for their survival. The proposed system utilizes a mechanically pumped, single phase fluid loop to pick up the waste heat from components attached to this loop's tubing and then directed to a thermal flask that has tubing attached to it. The thermal flask is cylindrically shaped and contains essentially all systems and components in the spacecraft within it, with the exception of the solar array, antennae, thrusters and various apertures of instruments, etc. to allow them an unobstructed view of space. Waste heat from the heat-dissipating components warms up the fluid and is carried to the flask surface and deposited on it via the fluid loop's flow. The entire flask is covered with Multi-Layered Insulation (MLI) to minimize the heat loss from the flask and allow it to remain warm. Hence the flask essentially creates a thermal environment within which the spacecraft components reside. The temperature of the components within the flask is then essentially the same as the temperature of the flask. This approach could be a very enabling feature for deep space missions. This paper describes the approach utilized for this thermal architecture, along with its mechanical and implementation aspects. Additionally it will compare and contrast this approach with the more conventional solutions utilized earlier.

Application of Ultrasonic Guided Waves for Evaluating Aging Wire Insulation

NASA Technical Reports Server (NTRS)

Anastasi, Robert F.; Madaras, Eric I.

2005-01-01

Aging wiring has become a critical issue to the aerospace and aircraft industries due to Shuttle and aircraft incidents. The problem is that over time the insulation on wire becomes brittle and cracks. This exposes the underlying conductive wire to the potential for short circuits and fire. Popular methods of monitoring aging wire problems focuses on applying electrical sensing techniques that are sensitive to the conductor's condition, but not very sensitive to the wire insulation's condition. Measurement of wire insulation stiffness and ultrasonic properties by ultrasonic guided waves is being examined. Experimental measurements showed that the lowest order extensional mode could be sensitive to stiffness changes in the wire insulation. To test this theory conventional wire samples were heat damaged in an oven, in a range of heating conditions. The samples were 12, 16, and 20 gauge and the heat damage introduced material changes in the wire insulation that made the originally flexible insulation brittle and darker in color. Results showed that extensional mode phase velocity increased for the samples that were exposed to heat for longer duration.

Evaporation from a shallow, saline lake in the Nebraska Sandhills: Energy balance drivers of seasonal and interannual variability

NASA Astrophysics Data System (ADS)

Riveros-Iregui, Diego A.; Lenters, John D.; Peake, Colin S.; Ong, John B.; Healey, Nathan C.; Zlotnik, Vitaly A.

2017-10-01

Despite potential evaporation rates in excess of the local precipitation, dry climates often support saline lakes through groundwater inputs of water and associated solutes. These groundwater-fed lakes are important indicators of environmental change, in part because their shallow water levels and salinity are very sensitive to weather and climatic variability. Some of this sensitivity arises from high rates of open-water evaporation, which is a dominant but poorly quantified process for saline lakes. This study used the Bowen ratio energy budget method to calculate open-water evaporation rates for Alkali Lake, a saline lake in the Nebraska Sandhills region (central United States), where numerous groundwater-fed lakes occupy the landscape. Evaporation rates were measured during the warm season (May - October) over three consecutive years (2007-2009) to gain insights into the climatic and limnological factors driving evaporation, as well as the partitioning of energy balance components at seasonal and interannual time scales. Results show a seasonal peak in evaporation rate in late June of 7.0 mm day-1 (on average), with a maximum daily rate of 10.5 mm day-1 and a 3-year mean July-September (JAS) rate of 5.1 mm day-1, which greatly exceeds the long-term JAS precipitation rate of 1.3 mm day-1. Seasonal variability in lake evaporation closely follows that of net radiation and lake surface temperature, with sensible heat flux and heat storage variations being relatively small, except in response to short-term, synoptic events. Interannual changes in the surface energy balance were weak, by comparison, although a 6-fold increase in mean lake level over the three years (0.05-0.30 m) led to greater heat storage within the lake, an enhanced JAS lake-air temperature gradient, and greater sensible heat loss. These large variations in water level were also associated with large changes in absolute salinity (from 28 to 118 g kg-1), with periods of high salinity characterized by reductions in mass transfer estimates of evaporation rate by up to 20%, depending on atmospheric conditions and absolute salinity. Energy balance estimates of evaporation, on the other hand, were found to be less sensitive to variations in salinity. These results provide regional insights for lakes in the Nebraska Sandhills region and implications for estimation of the energy and water balance of saline lakes in similar arid and semi-arid landscapes.

Development of sensors for ceramic components in advanced propulsion systems: Survey and evaluation of measurement techniques for temperature, strain and heat flux for ceramic components in advanced propulsion systems

NASA Technical Reports Server (NTRS)

Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

1988-01-01

The report presents the final results of Tasks 1 and 2, Development of Sensors for Ceramic Components in Advanced Propulsion Systems (NASA program NAS3-25141). During Task 1, an extensive survey was conducted of sensor concepts which have the potential for measuring surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. Each sensor concept was analyzed and evaluated under Task 2; sensor concepts were then recommended for further development. For temperature measurement, both pyrometry and thermographic phosphors are recommended for measurements up to and beyond the melting point of ceramic materials. For lower temperature test programs, the thin-film techniques offer advantages in the installation of temperature sensors. Optical strain measurement techniques are recommended because they offer the possibility of being useful at very high temperature levels. Techniques for the measurement of heat flux are recommended for development based on both a surface mounted sensor and the measurement of the temperature differential across a portion of a ceramic component or metallic substrate.

Residual stress prediction in a powder bed fusion manufactured Ti6Al4V hip stem

NASA Astrophysics Data System (ADS)

Barrett, Richard A.; Etienne, Titouan; Duddy, Cormac; Harrison, Noel M.

2017-10-01

Powder bed fusion (PBF) is a category of additive manufacturing (AM) that is particularly suitable for the production of 3D metallic components. In PBF, only material in the current build layer is at the required melt temperature, with the previously melted and solidified layers reducing in temperature, thus generating a significant thermal gradient within the metallic component, particularly for laser based PBF components. The internal thermal stresses are subsequently relieved in a post-processing heat-treatment step. Failure to adequately remove these stresses can result in cracking and component failure. A prototype hip stem was manufactured from Ti6Al4V via laser PBF but was found to have fractured during over-seas shipping. This study examines the evolution of thermal stresses during the laser PBF manufacturing and heat treatment processes of the hip stem in a 2D finite element analysis (FEA) and compares it to an electron beam PBF process. A custom written script for the automatic conversion of a gross geometry finite element model into a thin layer- by-layer finite element model was developed. The build process, heat treatment (for laser PBF) and the subsequent cooling were simulated at the component level. The results demonstrate the effectiveness of the heat treatment in reducing PBF induced thermal stresses, and the concentration of stresses in the region that fractured.

A finite element method based microwave heat transfer modeling of frozen multi-component foods

NASA Astrophysics Data System (ADS)

Pitchai, Krishnamoorthy

Microwave heating is fast and convenient, but is highly non-uniform. Non-uniform heating in microwave cooking affects not only food quality but also food safety. Most food industries develop microwavable food products based on "cook-and-look" approach. This approach is time-consuming, labor intensive and expensive and may not result in optimal food product design that assures food safety and quality. Design of microwavable food can be realized through a simulation model which describes the physical mechanisms of microwave heating in mathematical expressions. The objective of this study was to develop a microwave heat transfer model to predict spatial and temporal profiles of various heterogeneous foods such as multi-component meal (chicken nuggets and mashed potato), multi-component and multi-layered meal (lasagna), and multi-layered food with active packages (pizza) during microwave heating. A microwave heat transfer model was developed by solving electromagnetic and heat transfer equations using finite element method in commercially available COMSOL Multiphysics v4.4 software. The microwave heat transfer model included detailed geometry of the cavity, phase change, and rotation of the food on the turntable. The predicted spatial surface temperature patterns and temporal profiles were validated against the experimental temperature profiles obtained using a thermal imaging camera and fiber-optic sensors. The predicted spatial surface temperature profile of different multi-component foods was in good agreement with the corresponding experimental profiles in terms of hot and cold spot patterns. The root mean square error values of temporal profiles ranged from 5.8 °C to 26.2 °C in chicken nuggets as compared 4.3 °C to 4.7 °C in mashed potatoes. In frozen lasagna, root mean square error values at six locations ranged from 6.6 °C to 20.0 °C for 6 min of heating. A microwave heat transfer model was developed to include susceptor assisted microwave heating of a frozen pizza. The root mean square error values of transient temperature profiles of five locations ranged from 5.0 °C to 12.6 °C. A methodology was developed to incorporate electromagnetic frequency spectrum in the coupled electromagnetic and heat transfer model. Implementing the electromagnetic frequency spectrum in the simulation improved the accuracy of temperature field pattern and transient temperature profile as compared to mono-chromatic frequency of 2.45 GHz. The bulk moisture diffusion coefficient of cooked pasta was calculated as a function of temperature at a constant water activity using desorption isotherms.

Development of a cryogenic rotating heat pipe joint

NASA Technical Reports Server (NTRS)

1978-01-01

The performance of two critical technology components required for a continuously rotatable heat pipe: (1) a low-leakage rotatable coupling for the heat pipe pressure vessel, and (2) a rotatable internal wick, is reported. Performance and leakage requirements were established based on 12 months operation of a cryogenic rotatable heat pipe on a satellite in earth orbit.

Development of structural ceramic components for automobile applications

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

Kawamoto, H.

1995-12-01

Development efforts have been made in automobile technologies on heat engines to improve the power performance, the fuel economy, and so on. It is well recognized that ceramic applications are keys to succeed in such advanced heat engines, because of their good mechanical and thermal properties. This paper discusses present automobile applications of structural ceramic components and the expectations in automobile uses. The strength and reliability of mass-produced components for the engines are described with the manufacturing processes. The future R&D directions are recommended for structural ceramics.

Design Optimization Method for Composite Components Based on Moment Reliability-Sensitivity Criteria

NASA Astrophysics Data System (ADS)

Sun, Zhigang; Wang, Changxi; Niu, Xuming; Song, Yingdong

2017-08-01

In this paper, a Reliability-Sensitivity Based Design Optimization (RSBDO) methodology for the design of the ceramic matrix composites (CMCs) components has been proposed. A practical and efficient method for reliability analysis and sensitivity analysis of complex components with arbitrary distribution parameters are investigated by using the perturbation method, the respond surface method, the Edgeworth series and the sensitivity analysis approach. The RSBDO methodology is then established by incorporating sensitivity calculation model into RBDO methodology. Finally, the proposed RSBDO methodology is applied to the design of the CMCs components. By comparing with Monte Carlo simulation, the numerical results demonstrate that the proposed methodology provides an accurate, convergent and computationally efficient method for reliability-analysis based finite element modeling engineering practice.

Effects of heat stress on bovine preimplantation embryos produced in vitro

PubMed Central

SAKATANI, Miki

2017-01-01

Summer heat stress decreases the pregnancy rate in cattle and has been thought to be associated with the early embryonic death caused by the elevation of maternal body temperature. In vitro cultures have been widely used for the evaluation of effects of heat stress on oocytes, fertilization, preimplantation, and embryonic development. Susceptibility to heat stress is present in developmental stages from oocytes to cleavage-stage (before embryonic gene activation, EGA) embryos, leading to a consequent decrease in developmental competence. On the other hand, advanced-stage embryos such as morula or blastocysts have acquired thermotolerance. The mechanism for the developmental stage-dependent change in thermotolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. The supplementation of antioxidants to the culture media has been known to neutralize the detrimental effects of heat stress. Besides, EGA could be involved in acquisition of thermotolerance in later stages of embryos. Morulae or blastocysts can repair heat-induced unfolded proteins or prevent DNA damage occurring in processes such as apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the pregnancy rate under heat stress. However, frozen-thawed ET could not improve the pregnancy rate as expected. Frozen-thawed blastocysts were more sensitive to heat stress and showed less proliferation upon heat exposure, compared to fresh blastocysts. Therefore, further research is required to improve the reduction in pregnancy rates due to summer heat stress. PMID:28496018

Effects of heat stress on bovine preimplantation embryos produced in vitro.

PubMed

Sakatani, Miki

2017-08-19

Summer heat stress decreases the pregnancy rate in cattle and has been thought to be associated with the early embryonic death caused by the elevation of maternal body temperature. In vitro cultures have been widely used for the evaluation of effects of heat stress on oocytes, fertilization, preimplantation, and embryonic development. Susceptibility to heat stress is present in developmental stages from oocytes to cleavage-stage (before embryonic gene activation, EGA) embryos, leading to a consequent decrease in developmental competence. On the other hand, advanced-stage embryos such as morula or blastocysts have acquired thermotolerance. The mechanism for the developmental stage-dependent change in thermotolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. The supplementation of antioxidants to the culture media has been known to neutralize the detrimental effects of heat stress. Besides, EGA could be involved in acquisition of thermotolerance in later stages of embryos. Morulae or blastocysts can repair heat-induced unfolded proteins or prevent DNA damage occurring in processes such as apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the pregnancy rate under heat stress. However, frozen-thawed ET could not improve the pregnancy rate as expected. Frozen-thawed blastocysts were more sensitive to heat stress and showed less proliferation upon heat exposure, compared to fresh blastocysts. Therefore, further research is required to improve the reduction in pregnancy rates due to summer heat stress.

Detection of cocrystal formation based on binary phase diagrams using thermal analysis.

PubMed

Yamashita, Hiroyuki; Hirakura, Yutaka; Yuda, Masamichi; Teramura, Toshio; Terada, Katsuhide

2013-01-01

Although a number of studies have reported that cocrystals can form by heating a physical mixture of two components, details surrounding heat-induced cocrystal formation remain unclear. Here, we attempted to clarify the thermal behavior of a physical mixture and cocrystal formation in reference to a binary phase diagram. Physical mixtures prepared using an agate mortar were heated at rates of 2, 5, 10, and 30 °C/min using differential scanning calorimetry (DSC). Some mixtures were further analyzed using X-ray DSC and polarization microscopy. When a physical mixture consisting of two components which was capable of cocrystal formation was heated using DSC, an exothermic peak associated with cocrystal formation was detected immediately after an endothermic peak. In some combinations, several endothermic peaks were detected and associated with metastable eutectic melting, eutectic melting, and cocrystal melting. In contrast, when a physical mixture of two components which is incapable of cocrystal formation was heated using DSC, only a single endothermic peak associated with eutectic melting was detected. These experimental observations demonstrated how the thermal events were attributed to phase transitions occurring in a binary mixture and clarified the relationship between exothermic peaks and cocrystal formation.

A high-sensitivity tunable two-beam fiber-coupled high-density magnetometer with laser heating

DOE PAGES

Savukov, Igor Mykhaylovich; Boshier, Malcolm Geoffrey

2016-10-13

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz 1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. Here, this magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the applicationmore » of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz 1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications.« less

Expression of three mammalian cDNAs that interfere with RAS function in Saccharomyces cerevisiae.

PubMed Central

Colicelli, J; Nicolette, C; Birchmeier, C; Rodgers, L; Riggs, M; Wigler, M

1991-01-01

Saccharomyces cerevisiae strains expressing the activated RAS2Val19 gene or lacking both cAMP phosphodiesterase genes, PDE1 and PDE2, have impaired growth control and display an acute sensitivity to heat shock. We have isolated two classes of mammalian cDNAs from yeast expression libraries that suppress the heat shock-sensitive phenotype of RAS2Val19 strain. Members of the first class of cDNAs also suppress the heat shock-sensitive phenotype of pde1- pde2- strains and encode cAMP phosphodiesterases. Members of the second class fail to suppress the phenotype of pde1- pde2- strains and therefore are candidate cDNAs encoding proteins that interact with RAS proteins. We report the nucleotide sequence of three members of this class. Two of these cDNAs share considerable sequence similarity, but none are clearly similar to previously isolated genes. Images PMID:1849280

System and method of providing quick thermal comfort with reduced energy by using directed spot conditioning

DOEpatents

Wang, Mingyu; Kadle, Prasad S.; Ghosh, Debashis; Zima, Mark J.; Wolfe, IV, Edward; Craig, Timothy D

2016-10-04

A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

A High-Sensitivity Tunable Two-Beam Fiber-Coupled High-Density Magnetometer with Laser Heating

PubMed Central

Savukov, Igor; Boshier, Malcolm G.

2016-01-01

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. This magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the application of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications. PMID:27754358

Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components

NASA Technical Reports Server (NTRS)

Reyes, A. L.; Campbell, J. E.

1975-01-01

Dry heat treatment is specified as the preferred means for the terminal sterilization of spacecraft and for decontamination of spacecraft components. The presence of organisms highly resistant to dry heat in soil and fallout around assembly and industrial manufacturing areas is shown. The dry heat survival characteristics of the Cape Kennedy isolate 4-6 B. brevis spores is demonstrated. The presence of hardy organisms from soil samples obtained from geographical areas of the United States is shown. A resistant fraction appears to occur in low numbers in a soil sample. The heat resistance characteristics of 4-6 B. brevis and B. subtilis var. niger spores are compared. Their morphological characteristics are compared by scanning electron microscopy.

Numerical simulation of two-dimensional heat transfer in composite bodies with application to de-icing of aircraft components. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Chao, D. F. K.

1983-01-01

Transient, numerical simulations of the de-icing of composite aircraft components by electrothermal heating were performed for a two dimensional rectangular geometry. The implicit Crank-Nicolson formulation was used to insure stability of the finite-difference heat conduction equations and the phase change in the ice layer was simulated using the Enthalpy method. The Gauss-Seidel point iterative method was used to solve the system of difference equations. Numerical solutions illustrating de-icer performance for various composite aircraft structures and environmental conditions are presented. Comparisons are made with previous studies. The simulation can also be used to solve a variety of other heat conduction problems involving composite bodies.

The NASA-Lewis/ERDA Solar Heating and Cooling Technology Program

NASA Technical Reports Server (NTRS)

Couch, J. P.; Bloomfield, H. S.

1975-01-01

The NASA Lewis Research Center plans to carry out a major role in the ERDA Solar Heating and Cooling Program. This role would be to create and test the enabling technology for future solar heating, cooling, and combined heating/cooling systems. The major objectives of the project are to achieve reduction in solar energy system costs, while maintaining adequate performance, reliability, life, and maintenance characteristics. The project approach is to move progressively through component, subsystem, and then system technology advancement phases in parallel with continuing manufacturing cost assessment studies. This approach will be accomplished principally by contract with industry to develop advanced components and subsystems. This advanced hardware will be tested to establish 'technology readiness' both under controlled laboratory conditions and under real sun conditions.

FFT analysis of sensible-heat solar-dynamic receivers

NASA Astrophysics Data System (ADS)

Lund, Kurt O.

The use of solar dynamic receivers with sensible energy storage in single-phase materials is considered. The feasibility of single-phase designs with weight and thermal performance comparable to existing two-phase designs is addressed. Linearized heat transfer equations are formulated for the receiver heat storage, representing the periodic input solar flux as the sum of steady and oscillating distributions. The steady component is solved analytically to produce the desired receiver steady outlet gas temperature, and the FFT algorithm is applied to the oscillating components to obtain the amplitudes and mode shapes of the oscillating solid and gas temperatures. The results indicate that sensible-heat receiver designs with performance comparable to state-of-the-art two-phase receivers are available.

Observations and Modeling of Thermal Structure in the Lower Atmosphere and the Upward Propagation of Tides into the Thermosphere

NASA Technical Reports Server (NTRS)

Wilson, R. J.; Kahre, M.

2017-01-01

Thermal tides are the atmospheric response to diurnally varying thermal forcing resulting from radiative and convective heat transfer from the surface and from aerosol and gaseous heating within the atmosphere. Tides include sun-synchronous (migrating) waves driven in response to solar heating and additional non-migrating waves resulting from longitudinal variations in the distributions of topography, dust aerosol and water ice clouds. The systematic spatial mapping of temperature over 5 Mars years by the Mars Climate Sounder (MCS) has yielded a well-defined climatology of seasonally-varying temperature structures in the lower atmosphere, from 5 to 80 km. Tide theory and Mars global circulation model (MGCM) simulations are a fruitful framework for relating temperature observations to thermal forcing by aerosol fields [1]. The analysis of density and temperature fields derived from MAVEN IUVS and NGIMS observations have revealed the presence of predominantly zonal wave 2 and 3 features at altitudes of 100-170 km that are almost certainly non-migrating tides propagating upward from the lower atmosphere [2,3]. In this presentation we will use the MCS climatology and MGCM simulations to relate the density variations seen by MAVEN with the seasonally varying tide activity in the lower atmosphere. Large amplitude perturbations in density are most sensitive to the tide components with the longest vertical wavelengths in temperature, which are well resolved in MCS observations.

DART-MS analysis of inorganic explosives using high temperature thermal desorption†‡

PubMed Central

Sisco, Edward; Staymates, Matthew; Gillen, Greg

2018-01-01

An ambient mass spectrometry (MS) platform coupling resistive Joule heating thermal desorption (JHTD) and direct analysis in real time (DART) was implemented for the analysis of inorganic nitrite, nitrate, chlorate, and perchlorate salts. The resistive heating component generated discrete and rapid heating ramps and elevated temperatures, up to approximately 400 °C s−1 and 750 °C, by passing a few amperes of DC current through a nichrome wire. JHTD enhanced the utility and capabilities of traditional DART-MS for the trace detection of previously difficult to detect inorganic compounds. A partial factorial design of experiments (DOE) was implemented for the systematic evaluation of five system parameters. A base set of conditions for JHTD-DART-MS was derived from this evaluation, demonstrating sensitive detection of a range of inorganic oxidizer salts, down to single nanogram levels. DOE also identified JHTD filament current and in-source collision induced dissociation (CID) energy as inducing the greatest effect on system response. Tuning of JHTD current provided a method for controlling the relative degrees of thermal desorption and thermal decomposition. Furthermore, in-source CID provided manipulation of adduct and cluster fragmentation, optimizing the detection of molecular anion species. Finally, the differential thermal desorption nature of the JHTD-DART platform demonstrated efficient desorption and detection of organic and inorganic explosive mixtures, with each desorbing at its respective optimal temperature. PMID:29651308

Annual report, FY 1979 Spent fuel and fuel pool component integrity.

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

Johnson, A.B. Jr.; Bailey, W.J.; Schreiber, R.E.

International meetings under the BEFAST program and under INFCE Working Group No. 6 during 1978 and 1979 continue to indicate that no cases of fuel cladding degradation have developed on pool-stored fuel from water reactors. A section from a spent fuel rack stand, exposed for 1.5 y in the Yankee Rowe (PWR) pool had 0.001- to 0.003-in.-deep (25- to 75-..mu..m) intergranular corrosion in weld heat-affected zones but no evidence of stress corrosion cracking. A section of a 304 stainless steel spent fuel storage rack exposed 6.67 y in the Point Beach reactor (PWR) spent fuel pool showed no significant corrosion.more » A section of 304 stainless steel 8-in.-dia pipe from the Three Mile Island No. 1 (PWR) spent fuel pool heat exchanger plumbing developed a through-wall crack. The crack was intergranular, initiating from the inside surface in a weld heat-affected zone. The zone where the crack occurred was severely sensitized during field welding. The Kraftwerk Union (Erlangen, GFR) disassembled a stainless-steel fuel-handling machine that operated for 12 y in a PWR (boric acid) spent fuel pool. There was no evidence of deterioration, and the fuel-handling machine was reassembled for further use. A spent fuel pool at a Swedish PWR was decontaminated. The procedure is outlined in this report.« less

An algorithm for the kinetics of tire pyrolysis under different heating rates.

PubMed

Quek, Augustine; Balasubramanian, Rajashekhar

2009-07-15

Tires exhibit different kinetic behaviors when pyrolyzed under different heating rates. A new algorithm has been developed to investigate pyrolysis behavior of scrap tires. The algorithm includes heat and mass transfer equations to account for the different extents of thermal lag as the tire is heated at different heating rates. The algorithm uses an iterative approach to fit model equations to experimental data to obtain quantitative values of kinetic parameters. These parameters describe the pyrolysis process well, with good agreement (r(2)>0.96) between the model and experimental data when the model is applied to three different brands of automobile tires heated under five different heating rates in a pure nitrogen atmosphere. The model agrees with other researchers' results that frequencies factors increased and time constants decreased with increasing heating rates. The model also shows the change in the behavior of individual tire components when the heating rates are increased above 30 K min(-1). This result indicates that heating rates, rather than temperature, can significantly affect pyrolysis reactions. This algorithm is simple in structure and yet accurate in describing tire pyrolysis under a wide range of heating rates (10-50 K min(-1)). It improves our understanding of the tire pyrolysis process by showing the relationship between the heating rate and the many components in a tire that depolymerize as parallel reactions.

LOX/GOX sensitivity of fluoroelastomers. [effect of formulation components and addition of fire retardants

NASA Technical Reports Server (NTRS)

Kirshen, N.; Mill, T.

1973-01-01

The effect of formulation components and the addition of fire retardants on the impact sensitivity of Viton B fluoroelastomer in liquid oxygen was studied with the objective of developing a procedure for reliably reducing this sensitivity. Component evaluation, carried out on more than 40 combinations of components and cure cycles, showed that almost all the standard formulation agents, including carbon, MgO, Diak-3, and PbO2, will sensitize the Viton stock either singly or in combinations, some combinations being much more sensitive than others. Cure and postcure treatments usually reduced the sensitivity of a given formulation, often dramatically, but no formulated Viton was as insensitive as the pure Viton B stock. Coating formulated Viton with a thin layer of pure Viton gave some indication of reduced sensitivity, but additional tests are needed. It is concluded that sensitivity in formulated Viton arises from a variety of sources, some physical and some chemical in origin. Elemental analyses for all the formulated Vitons are reported as are the results of a literature search on the subject of LOX impact sensitivity.

Tactical Radar Technology Study. Volume II.

DTIC Science & Technology

1980-03-01

area around the component by air conditioning of some nature. The electronic components are solid state and densely packaged. The use of heat pipe ...capabilities. The heat pipe industry may be able to achieve considerable improvement. A tactical assessment of the threat resistance threshold required...Operating -60 to +1550 F (+ Solar Radiation) Temperature Nonoperating -70 to +155F Relative Humidity 100% Winds 45 knots - operation 45-60 knots

Plasma-based proteomics reveals immune response, complement and coagulation cascades pathway shifts in heat-stressed lactating dairy cows.

PubMed

Min, Li; Cheng, Jianbo; Zhao, Shengguo; Tian, He; Zhang, Yangdong; Li, Songli; Yang, Hongjian; Zheng, Nan; Wang, Jiaqi

2016-09-02

Heat stress (HS) has an enormous economic impact on the dairy industry. In recent years, many researchers have investigated changes in the gene expression and metabolomics profiles in dairy cows caused by HS. However, the proteomics profiles of heat-stressed dairy cows have not yet been completely elucidated. We compared plasma proteomics from HS-free and heat-stressed dairy cows using an iTRAQ labeling approach. After the depletion of high abundant proteins in the plasma, 1472 proteins were identified. Of these, 85 proteins were differentially abundant in cows exposed to HS relative to HS-free. Database searches combined with GO and KEGG pathway enrichment analyses revealed that many components of the complement and coagulation cascades were altered in heat-stressed cows compared with HS-free cows. Of these, many factors in the complement system (including complement components C1, C3, C5, C6, C7, C8, and C9, complement factor B, and factor H) were down-regulated by HS, while components of the coagulation system (including coagulation factors, vitamin K-dependent proteins, and fibrinogens) were up-regulated by HS. In conclusion, our results indicate that HS decreases plasma levels of complement system proteins, suggesting that immune function is impaired in dairy cows exposed to HS. Though many aspects of heat stress (HS) have been extensively researched, relatively little is known about the proteomics profile changes that occur during heat exposure. In this work, we employed a proteomics approach to investigate differential abundance of plasma proteins in HS-free and heat-stressed dairy cows. Database searches combined with GO and KEGG pathway enrichment analyses revealed that HS resulted in a decrease in complement components, suggesting that heat-stressed dairy cows have impaired immune function. In addition, through integrative analyses of proteomics and previous metabolomics, we showed enhanced glycolysis, lipid metabolic pathway shifts, and nitrogen repartitioning in dairy cows exposed to HS. Our findings expand our current knowledge on the effects of HS on plasma proteomics in dairy cows and offer a new perspective for future research. Copyright © 2016 Elsevier B.V. All rights reserved.

Estimating spatially distributed turbulent heat fluxes from high-resolution thermal imagery acquired with a UAV system

PubMed Central

Brenner, Claire; Thiem, Christina Elisabeth; Wizemann, Hans-Dieter; Bernhardt, Matthias; Schulz, Karsten

2017-01-01

ABSTRACT In this study, high-resolution thermal imagery acquired with a small unmanned aerial vehicle (UAV) is used to map evapotranspiration (ET) at a grassland site in Luxembourg. The land surface temperature (LST) information from the thermal imagery is the key input to a one-source and two-source energy balance model. While the one-source model treats the surface as a single uniform layer, the two-source model partitions the surface temperature and fluxes into soil and vegetation components. It thus explicitly accounts for the different contributions of both components to surface temperature as well as turbulent flux exchange with the atmosphere. Contrary to the two-source model, the one-source model requires an empirical adjustment parameter in order to account for the effect of the two components. Turbulent heat flux estimates of both modelling approaches are compared to eddy covariance (EC) measurements using the high-resolution input imagery UAVs provide. In this comparison, the effect of different methods for energy balance closure of the EC data on the agreement between modelled and measured fluxes is also analysed. Additionally, the sensitivity of the one-source model to the derivation of the empirical adjustment parameter is tested. Due to the very dry and hot conditions during the experiment, pronounced thermal patterns developed over the grassland site. These patterns result in spatially variable turbulent heat fluxes. The model comparison indicates that both models are able to derive ET estimates that compare well with EC measurements under these conditions. However, the two-source model, with a more complex treatment of the energy and surface temperature partitioning between the soil and vegetation, outperformed the simpler one-source model in estimating sensible and latent heat fluxes. This is consistent with findings from prior studies. For the one-source model, a time-variant expression of the adjustment parameter (to account for the difference between aerodynamic and radiometric temperature) that depends on the surface-to-air temperature gradient yielded the best agreement with EC measurements. This study showed that the applied UAV system equipped with a dual-camera set-up allows for the acquisition of thermal imagery with high spatial and temporal resolution that illustrates the small-scale heterogeneity of thermal surface properties. The UAV-based thermal imagery therefore provides the means for analysing patterns of LST and other surface properties with a high level of detail that cannot be obtained by traditional remote sensing methods. PMID:28515537

Estimating spatially distributed turbulent heat fluxes from high-resolution thermal imagery acquired with a UAV system.

PubMed

Brenner, Claire; Thiem, Christina Elisabeth; Wizemann, Hans-Dieter; Bernhardt, Matthias; Schulz, Karsten

2017-05-19

In this study, high-resolution thermal imagery acquired with a small unmanned aerial vehicle (UAV) is used to map evapotranspiration (ET) at a grassland site in Luxembourg. The land surface temperature (LST) information from the thermal imagery is the key input to a one-source and two-source energy balance model. While the one-source model treats the surface as a single uniform layer, the two-source model partitions the surface temperature and fluxes into soil and vegetation components. It thus explicitly accounts for the different contributions of both components to surface temperature as well as turbulent flux exchange with the atmosphere. Contrary to the two-source model, the one-source model requires an empirical adjustment parameter in order to account for the effect of the two components. Turbulent heat flux estimates of both modelling approaches are compared to eddy covariance (EC) measurements using the high-resolution input imagery UAVs provide. In this comparison, the effect of different methods for energy balance closure of the EC data on the agreement between modelled and measured fluxes is also analysed. Additionally, the sensitivity of the one-source model to the derivation of the empirical adjustment parameter is tested. Due to the very dry and hot conditions during the experiment, pronounced thermal patterns developed over the grassland site. These patterns result in spatially variable turbulent heat fluxes. The model comparison indicates that both models are able to derive ET estimates that compare well with EC measurements under these conditions. However, the two-source model, with a more complex treatment of the energy and surface temperature partitioning between the soil and vegetation, outperformed the simpler one-source model in estimating sensible and latent heat fluxes. This is consistent with findings from prior studies. For the one-source model, a time-variant expression of the adjustment parameter (to account for the difference between aerodynamic and radiometric temperature) that depends on the surface-to-air temperature gradient yielded the best agreement with EC measurements. This study showed that the applied UAV system equipped with a dual-camera set-up allows for the acquisition of thermal imagery with high spatial and temporal resolution that illustrates the small-scale heterogeneity of thermal surface properties. The UAV-based thermal imagery therefore provides the means for analysing patterns of LST and other surface properties with a high level of detail that cannot be obtained by traditional remote sensing methods.

Mini-Brayton heat source assembly development

NASA Technical Reports Server (NTRS)

Wein, D.; Zimmerman, W. F.

1978-01-01

The work accomplished on the Mini-Brayton Heat Source Assembly program is summarized. Required technologies to design, fabricate and assemble components for a high temperature Heat Source Assembly (HSA) which would generate and transfer the thermal energy for a spaceborne Brayton Isotope Power System (BIPS) were developed.