heat environment pattern: Topics by Science.gov

Sample records for heat environment pattern

Heat-coping strategies and bedroom thermal satisfaction in New York City.

PubMed

Lee, W Victoria; Shaman, Jeffrey

2017-01-01

There has been little research into the thermal condition of the sleeping environment. Even less well documented and understood is how the sleeping thermal environment is affected by occupant behaviors such as the use of air-conditioning (AC) and electric fans, or window operations. In this paper we present results from a questionnaire survey administered to assess summertime bedroom thermal satisfaction and heat-coping strategies among New York City (NYC) residents. Specifically, we investigated current AC usage in bedrooms and examined alternate cooling strategies, cooling appliance usage patterns, and the motivations that drove these patterns during the 2015 summer. Among survey respondents (n=706), AC was the preferred heat-coping strategy, and for 30% of respondents was the only strategy used. Electric fan use and window opening were deemed ineffective for cooling by many respondents. Indeed, less than a quarter of all respondents ever opened windows to alleviate heat in their bedrooms. In general, people utilized strategies that modify the environment more than the individual person. Unsurprisingly, the frequency and overall use of AC were significantly associated with greater bedroom thermal satisfaction; however, setting AC to a lower temperature provided no additional benefit. In contrast, more frequent use of electric fans was associated with lower thermal satisfaction. In addition, 14.7% of all respondents did not have AC in their sleeping environment and 5.8% were without any AC at home. Despite the high penetration of AC ownership, usage cost was still a major concern for most. This work contributes to a better understanding of bedtime heat-coping strategies, cooling appliance usage patterns, and associated thermal satisfaction in NYC. The findings of this study suggest resident AC usage patterns may not be optimized for thermal satisfaction. Potential alternative cooling approaches could be explored to better balance maximizing thermal comfort while reducing energy consumption and environmental impact. Copyright © 2016 Elsevier B.V. All rights reserved.
Stress-induced thermotolerance of ventilatory motor pattern generation in the locust, Locusta migratoria.

PubMed

Newman, Amy E M; Foerster, Melody; Shoemaker, Kelly L; Robertson, R Meldrum

2003-11-01

Ventilation is a crucial motor activity that provides organisms with an adequate circulation of respiratory gases. For animals that exist in harsh environments, an important goal is to protect ventilation under extreme conditions. Heat shock, anoxia, and cold shock are environmental stresses that have previously been shown to trigger protective responses. We used the locust to examine stress-induced thermotolerance by monitoring the ability of the central nervous system to generate ventilatory motor patterns during a subsequent heat exposure. Preparations from pre-stressed animals had an increased incidence of motor pattern recovery following heat-induced failure, however, prior stress did not alter the characteristics of the ventilatory motor pattern. During constant heat exposure at sub-lethal temperatures, we observed a protective effect of heat shock pre-treatment. Serotonin application had similar effects on motor patterns when compared to prior heat shock. These studies are consistent with previous studies that indicate prior exposure to extreme temperatures and hypoxia can protect neural operation against high temperature stress. They further suggest that the protective mechanism is a time-dependent process best revealed during prolonged exposure to extreme temperatures and is mediated by a neuromodulator such as serotonin.
Solar-powered ventilation of African termite mounds.

PubMed

Ocko, Samuel A; King, Hunter; Andreen, David; Bardunias, Paul; Turner, J Scott; Soar, Rupert; Mahadevan, L

2017-09-15

How termite mounds function to facilitate climate control is still only partially understood. Recent experimental evidence in the mounds of a single species, the south Asian termite Odontotermes obesus , suggests that the daily oscillations of radiant heating associated with diurnal insolation patterns drive convective flow within them. How general this mechanism is remains unknown. To probe this, we consider the mounds of the African termite Macrotermes michaelseni , which thrives in a very different environment. By directly measuring air velocities and temperatures within the mound, we see that the overall mechanisms and patterns involved are similar to that in the south Asian species. However, there are also some notable differences between the physiology of these mounds associated with the temporal variations in radiant heating patterns and CO 2 dynamics. Because of the difference between direct radiant heating driven by the position of the sun in African conditions, and the more shaded south Asian environments, we see changes in the convective flows in the two types of mounds. Furthermore, we also see that the south Asian mounds show a significant overturning of stratified gases, once a day, while the African mounds have a relatively uniform concentration of CO 2 Overall, our observations show that despite these differences, termite architectures can harness periodic solar heating to drive ventilation inside them in very different environments, functioning as an external lung, with clear implications for human engineering. © 2017. Published by The Company of Biologists Ltd.
Thermodynamics of complexity and pattern manipulation.

PubMed

Garner, Andrew J P; Thompson, Jayne; Vedral, Vlatko; Gu, Mile

2017-04-01

Many organisms capitalize on their ability to predict the environment to maximize available free energy and reinvest this energy to create new complex structures. This functionality relies on the manipulation of patterns-temporally ordered sequences of data. Here, we propose a framework to describe pattern manipulators-devices that convert thermodynamic work to patterns or vice versa-and use them to build a "pattern engine" that facilitates a thermodynamic cycle of pattern creation and consumption. We show that the least heat dissipation is achieved by the provably simplest devices, the ones that exhibit desired operational behavior while maintaining the least internal memory. We derive the ultimate limits of this heat dissipation and show that it is generally nonzero and connected with the pattern's intrinsic crypticity-a complexity theoretic quantity that captures the puzzling difference between the amount of information the pattern's past behavior reveals about its future and the amount one needs to communicate about this past to optimally predict the future.
Analysis of Radiation-natural Convection Interactions in 1-g and low-g Environments using the Discrete Exchange Factor Method

NASA Technical Reports Server (NTRS)

Kassemi, M.; Naraghi, M. H. N.

1993-01-01

A new numerical method is presented for the analysis of combined natural convection and radiation heat transfer with applications in many engineering situations such as materials processing, combustion and fire research. Because of the recent interest in the low gravity environment of space, attention is devoted to both 1-g and low-g applications. The two-dimensional mathematical model is represented by a set of coupled nonlinear integro-partial differential equations. Radiative exchange is formulated using the Discrete Exchange Factor method (DEF). This method considers point to point exchange and provides accurate results over a wide range of radiation parameters. Numerical results show that radiation significantly influences the flow and heat transfer in both low-g and 1-g applications. In the low-g environment, convection is weak, and radiation can easily become the dominant heat transfer mode. It is also shown that volumetric heating by radiation gives rise to an intricate cell pattern in the top heated enclosure.
Thermodynamics of complexity and pattern manipulation

NASA Astrophysics Data System (ADS)

Garner, Andrew J. P.; Thompson, Jayne; Vedral, Vlatko; Gu, Mile

2017-04-01

Many organisms capitalize on their ability to predict the environment to maximize available free energy and reinvest this energy to create new complex structures. This functionality relies on the manipulation of patterns—temporally ordered sequences of data. Here, we propose a framework to describe pattern manipulators—devices that convert thermodynamic work to patterns or vice versa—and use them to build a "pattern engine" that facilitates a thermodynamic cycle of pattern creation and consumption. We show that the least heat dissipation is achieved by the provably simplest devices, the ones that exhibit desired operational behavior while maintaining the least internal memory. We derive the ultimate limits of this heat dissipation and show that it is generally nonzero and connected with the pattern's intrinsic crypticity—a complexity theoretic quantity that captures the puzzling difference between the amount of information the pattern's past behavior reveals about its future and the amount one needs to communicate about this past to optimally predict the future.
Multi Seasonal and Diurnal Characterization of Sensible Heat Flux in an Arid Land Environment

NASA Astrophysics Data System (ADS)

Al-Mashharawi, S.; Aragon, B.; McCabe, M.

2017-12-01

In sparsely vegetated arid and semi-arid regions, the available energy is transformed primarily into sensible heat, with little to no energy partitioned into latent heat. The characterization of bare soil arid environments are rather poorly understood in the context of both local, regional and global energy budgets. Using data from a long-term surface layer scintillometer and co-located meteorological installation, we examine the diurnal and seasonal patterns of sensible heat flux and the net radiation to soil heat flux ratio. We do this over a bare desert soil located adjacent to an irrigated agricultural field in the central region of Saudi Arabia. The results of this exploratory analysis can be used to inform upon remote sensing techniques for surface flux estimation, to derive and monitor soil heat flux dynamics, estimate the heat transfer resistance and the thermal roughness length over bare soils, and to better inform efforts that model the advective effects that complicate the accurate representation of agricultural energy budgets in the arid zone.
Human Physiological Responses to Acute and Chronic Cold Exposure

NASA Technical Reports Server (NTRS)

Stocks, Jodie M.; Taylor, Nigel A. S.; Tipton, Michael J.; Greenleaf, John E.

2001-01-01

When inadequately protected humans are exposed to acute cold, excessive body heat is lost to the environment and unless heat production is increased and heat loss attenuated, body temperature will decrease. The primary physiological responses to counter the reduction in body temperature include marked cutaneous vasoconstriction and increased metabolism. These responses, and the hazards associated with such exposure, are mediated by a number of factors which contribute to heat production and loss. These include the severity and duration of the cold stimulus; exercise intensity; the magnitude of the metabolic response; and individual characteristics such as body composition, age, and gender. Chronic exposure to a cold environment, both natural and artificial, results in physiological alterations leading to adaptation. Three quite different, but not necessarily exclusive, patterns of human cold adaptation have been reported: metabolic, hypothermic, and insulative. Cold adaptation has also been associated with an habituation response, in which there is a desensitization, or damping, of the normal response to a cold stress. This review provides a comprehensive analysis of the human physiological and pathological responses to cold exposure. Particular attention is directed to the factors contributing to heat production and heat loss during acute cold stress, and the ability of humans to adapt to cold environments.
High temperature antenna development for space shuttle, volume 2. [space environment simulation effects on antenna radiation patterns

NASA Technical Reports Server (NTRS)

Kuhlman, E. A.

1974-01-01

An S-band antenna system and a group of off-the-shelf aircraft antenna were exposed to temperatures simulating shuttle orbital cold soak and entry heating. Radiation pattern and impedance measurements before and after exposure to the thermal environments were used to evaluate the electrical performance. The results of the electrical and thermal testing are given. Test data showed minor changes in electrical performance and established the capability of these antenna to withstand both the low temperatures of space flight and the high temperatures of entry.
Environmentally induced changes in correlated responses to selection reveal variable pleiotropy across a complex genetic network.

PubMed

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

2015-05-01

Selection in novel environments can lead to a coordinated evolutionary response across a suite of characters. Environmental conditions can also potentially induce changes in the genetic architecture of complex traits, which in turn could alter the pattern of the multivariate response to selection. We describe a factorial selection experiment using the nematode Caenorhabditis remanei in which two different stress-related phenotypes (heat and oxidative stress resistance) were selected under three different environmental conditions. The pattern of covariation in the evolutionary response between phenotypes or across environments differed depending on the environment in which selection occurred, including asymmetrical responses to selection in some cases. These results indicate that variation in pleiotropy across the stress response network is highly sensitive to the external environment. Our findings highlight the complexity of the interaction between genes and environment that influences the ability of organisms to acclimate to novel environments. They also make clear the need to identify the underlying genetic basis of genetic correlations in order understand how patterns of pleiotropy are distributed across complex genetic networks. © 2015 The Author(s).
ENVIRONMENTALLY INDUCED CHANGES IN CORRELATED RESPONSES TO SELECTION REVEAL VARIABLE PLEIOTROPY ACROSS A COMPLEX GENETIC NETWORK

PubMed Central

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

2017-01-01

Selection in novel environments can lead to a coordinated evolutionary response across a suite of characters. Environmental conditions can also potentially induce changes in the genetic architecture of complex traits, which in turn could alter the pattern of the multivariate response to selection. We describe a factorial selection experiment using the nematode Caenorhabditis remanei in which two different stress-related phenotypes (heat and oxidative stress resistance) were selected under three different environmental conditions. The pattern of covariation in the evolutionary response between phenotypes or across environments differed depending on the environment in which selection occurred, including asymmetrical responses to selection in some cases. These results indicate that variation in pleiotropy across the stress response network is highly sensitive to the external environment. Our findings highlight the complexity of the interaction between genes and environment that influences the ability of organisms to acclimate to novel environments. They also make clear the need to identify the underlying genetic basis of genetic correlations in order understand how patterns of pleiotropy are distributed across complex genetic networks. PMID:25809411
Heat-enhanced peptide synthesis on Teflon-patterned paper.

PubMed

Deiss, Frédérique; Yang, Yang; Matochko, Wadim L; Derda, Ratmir

2016-06-14

In this report, we describe the methodology for 96 parallel organic syntheses of peptides on Teflon-patterned paper assisted by heating with an infra-red lamp. SPOT synthesis is an important technology for production of peptide arrays on a paper-based support for rapid identification of peptide ligands, epitope mapping, and identification of bio-conjugation reactions. The major drawback of the SPOT synthesis methodology published to-date is suboptimal reaction conversion due to mass transport limitations in the unmixed reaction spot. The technology developed in this report overcomes these problems by changing the environment of the reaction from static to dynamic (flow-through), and further accelerating the reaction by selective heating of the reaction support in contact with activated amino acids. Patterning paper with Teflon allows for droplets of organic solvents to be confined in a zone on the paper array and flow through the paper at a well-defined rate and provide a convenient, power-free setup for flow-through solid-phase synthesis and efficient assembly of peptide arrays. We employed an infra-red (IR) lamp to locally heat the cellulosic support during the flow-through delivery of the reagents to each zone of the paper-based array. We demonstrate that IR-heating in solid phase peptide synthesis shortened the reaction time necessary for amide bond formation down to 3 minutes; in some couplings of alpha amino acids, conversion rates increased up to fifteen folds. The IR-heating improved the assembly of difficult sequences, such as homo-oligomers of all 20 natural amino acids.
Metal photonics and plasmonics for energy generation

NASA Astrophysics Data System (ADS)

Nagpal, Prashant

Energy generation from renewable sources and conservation of energy are important goals for reducing our carbon footprint on the environment. Important sources of renewable energy like sun and geothermal energy are difficult to harness because of their energetically broad radiation. Most of our current energy requirements are met through consumption of fossil fuels, and more than 60% of this energy is released to the environment as "waste heat". Thus, converting heat from sun, or inefficient furnaces and automobiles can provide an important source of energy generation. In the present work, I describe design, fabrication, and characterization two and three dimensional patterned metals. These nanofabricated structures can be used as selective emitters to tailor the glow of hot objects. The tailored radiation can then be converted efficiently into electricity using an infrared photocell. This thermophotovoltaic conversion can be very efficient, and useful for converting heat-to-electricity from a wide variety of sources.
Bacterial community dynamics are linked to patterns of coral heat tolerance

NASA Astrophysics Data System (ADS)

Ziegler, Maren; Seneca, Francois O.; Yum, Lauren K.; Palumbi, Stephen R.; Voolstra, Christian R.

2017-02-01

Ocean warming threatens corals and the coral reef ecosystem. Nevertheless, corals can be adapted to their thermal environment and inherit heat tolerance across generations. In addition, the diverse microbes that associate with corals have the capacity for more rapid change, potentially aiding the adaptation of long-lived corals. Here, we show that the microbiome of reef corals is different across thermally variable habitats and changes over time when corals are reciprocally transplanted. Exposing these corals to thermal bleaching conditions changes the microbiome for heat-sensitive corals, but not for heat-tolerant corals growing in habitats with natural high heat extremes. Importantly, particular bacterial taxa predict the coral host response in a short-term heat stress experiment. Such associations could result from parallel responses of the coral and the microbial community to living at high natural temperatures. A competing hypothesis is that the microbial community and coral heat tolerance are causally linked.
How Things Work. Teacher's Guide.

ERIC Educational Resources Information Center

Brown, Mark; And Others

This unit examines the earth's processes and systems from an energy perspective. A technical language for discussion of energy systems is developed. Objectives include the ability of students to discuss earth's carbon/oxygen cycle, hydrological cycle, and heat patterns and the functioning of producers, consumers and decomposers in the environment.…
Temporal patterns of cardiac performance and genes encoding heat shock proteins and metabolic sensors of an intertidal limpet Cellana toreuma during sublethal heat stress.

PubMed

Zhang, Shu; Han, Guo-dong; Dong, Yun-wei

2014-04-01

Intertidal invertebrates develop effective physiological adaptations to cope with the rapidly changing thermal environment in the intertidal zone. In the present study, the temporal patterns of heart rate, protein carbonyl groups, and genes encoding heat shock proteins (hsp70 and hsp90) and metabolic sensors (ampkα, ampkβ and sirt1) were measured to study the effect of sublethal heat stress on the cardiac function, oxidative stress, heat shock response and cellular metabolism of an intertidal limpet Cellana toreuma. All the physiological parameters are sensitive to temperature and duration of heat stress. Spearman correlation analysis revealed that the correlations between heart rate and levels of heat shock proteins mRNA and metabolic sensors mRNA were statistically significant. These results further suggest that cardiac function plays crucial roles in cellular energy metabolism and heat shock responses. The significant increase of protein carbonyl groups at 34°C after 4h exposure indicated that the failure of cardiac function and the increase of anaerobic metabolism partly leads to the increase of protein carbonyl groups. Generally, the physiological responses to heat stress are sensitive to temperature and are energy-consumptive, as indicated by the upregulation of metabolic sensors mRNA. However, the upregulation of heat shock proteins and metabolic sensors at the post-transcriptional level and related functions need to be confirmed in further experiments. Copyright © 2014 Elsevier Ltd. All rights reserved.
A study of mesoscale surface heat and moisture budgets and their relationship to airmass cumulus clouds observed in LANDSAT imagery. [Manhatten, Kansas and Fargo, North Dakota

NASA Technical Reports Server (NTRS)

Merritt, E. S. (Principal Investigator); Sabatini, R. R.; Heitkemper, L.; Hart, W. D.; Hlavka, D. L.

1976-01-01

The author has identified the following significant results. The three budget analyses show a weak correspondence between LANDSAT cloud patterns and elements of the energy and moisture budgets. It was found that a little more energy is contributed by the ground to heat the air in cloudy areas. Improvements are warranted in the budget models and data coverage necessary to describe the environment. These models can serve as a basis for more complex models of surface air heat and moisture exchanges which would utilize readily available meteorological data on a mesoscale.
The role of stochastic thermal environments in modulating the thermal physiology of an intertidal limpet, Lottia digitalis.

PubMed

Drake, Madeline J; Miller, Nathan A; Todgham, Anne E

2017-09-01

Much of our understanding of the thermal physiology of intertidal organisms comes from experiments with animals acclimated under constant conditions and exposed to a single heat stress. In nature, however, the thermal environment is more complex. Aerial exposure and the unpredictable nature of thermal stress during low tides may be critical factors in defining the thermal physiology of intertidal organisms. In the fingered limpet, Lottia digitalis , we investigated whether upper temperature tolerance and thermal sensitivity were influenced by the pattern of fluctuation with which thermal stress was applied. Specifically, we examined whether there was a differential response (measured as cardiac performance) to repeated heat stress of a constant and predictable magnitude compared with heat stress applied in a stochastic and unpredictable nature. We also investigated differences in cellular metabolism and damage following immersion for insights into biochemical mechanisms of tolerance. Upper temperature tolerance increased with aerial exposure, but no significant differences were found between predictable treatments of varying magnitudes (13°C versus 24°C versus 32°C). Significant differences in thermal tolerance were found between unpredictable trials with different heating patterns. There were no significant differences among treatments in basal citrate synthase activity, glycogen content, oxidative stress or antioxidants. Our results suggest that aerial exposure and recent thermal history, paired with relief from high low-tide temperatures, are important factors modulating the capacity of limpets to deal with thermal stress. © 2017. Published by The Company of Biologists Ltd.
In the Shade of Affluence: The Inequitable Distribution of the Urban Heat Island

NASA Technical Reports Server (NTRS)

Harlan, Sharon L.; Brazel, Anthony J.; Jenerette, G. Darrel; Jones, Nancy S.; Larsen, Larissa; Prashad, Lela

2008-01-01

The urban heat island is an unintended consequence of humans building upon rural and native landscapes. We hypothesized that variations in vegetation and land use patterns across an urbanizing regional landscape would produce a temperature distribution that was spatially heterogeneous and correlated with the social characteristics of urban neighborhoods. Using biophysical and social data scaled to conform to US census geography, we found that affluent whites were more likely to live in vegetated and less climatically stressed neighborhoods likely to live in than low-income Latinos in Phoenix, Arizona. Affluent neighborhoods had cooler summer temperatures that reduced exposure to outdoor heat-related health risks, especially during a heat wave period. In addition to being warmer, poorer neighborhoods lacked critical resources in their physical and social environments to help them cope with extreme heat. Increased average temperatures due to climate change are expected to exacerbate the impacts of urban heat islands.
GEM-CEDAR Challenge: Poynting Flux at DMSP and Modeled Joule Heat

NASA Technical Reports Server (NTRS)

Rastaetter, Lutz; Shim, Ja Soon; Kuznetsova, Maria M.; Kilcommons, Liam M.; Knipp, Delores J.; Codrescu, Mihail; Fuller-Rowell, Tim; Emery, Barbara; Weimer, Daniel R.; Cosgrove, Russell;

2016-01-01

Poynting flux into the ionosphere measures the electromagnetic energy coming from the magnetosphere. This energy flux can vary greatly between quiet times and geomagnetic active times. As part of the Geospace Environment Modeling-coupling energetics and dynamics of atmospheric regions modeling challenge, physics-based models of the 3-D ionosphere and ionospheric electrodynamics solvers of magnetosphere models that specify Joule heat and empirical models specifying Poynting flux were run for six geomagnetic storm events of varying intensity. We compared model results with Poynting flux values along the DMSP-15 satellite track computed from ion drift meter and magnetic field observations. Although being a different quantity, Joule heat can in practice be correlated to incoming Poynting flux because the energy is dissipated primarily in high latitudes where Poynting flux is being deposited. Within the physics-based model group, we find mixed results with some models overestimating Joule heat and some models agreeing better with observed Poynting flux rates as integrated over auroral passes. In contrast, empirical models tend to underestimate integrated Poynting flux values. Modeled Joule heat or Poynting flux patterns often resemble the observed Poynting flux patterns on a large scale, but amplitudes can differ by a factor of 2 or larger due to the highly localized nature of observed Poynting flux deposition that is not captured by the models. In addition, the positioning of modeled patterns appear to be randomly shifted against the observed Poynting flux energy input. This study is the first to compare Poynting flux and Joule heat in a large variety of models of the ionosphere.

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
Buried mine detection using fractal geometry analysis to the LWIR successive line scan data image

NASA Astrophysics Data System (ADS)

Araki, Kan

2012-06-01

We have engaged in research on buried mine/IED detection by remote sensing method using LWIR camera. A IR image of a ground, containing buried objects can be assumed as a superimposed pattern including thermal scattering which may depend on the ground surface roughness, vegetation canopy, and effect of the sun light, and radiation due to various heat interaction caused by differences in specific heat, size, and buried depth of the objects and local temperature of their surrounding environment. In this cumbersome environment, we introduce fractal geometry for analyzing from an IR image. Clutter patterns due to these complex elements have oftentimes low ordered fractal dimension of Hausdorff Dimension. On the other hand, the target patterns have its tendency of obtaining higher ordered fractal dimension in terms of Information Dimension. Random Shuffle Surrogate method or Fourier Transform Surrogate method is used to evaluate fractional statistics by applying shuffle of time sequence data or phase of spectrum. Fractal interpolation to each line scan was also applied to improve the signal processing performance in order to evade zero division and enhance information of data. Some results of target extraction by using relationship between low and high ordered fractal dimension are to be presented.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Constantz, Jim; Su, Grace; Hatch, Christine

Both the measurement of temperature and the simulation of heat and water transport have benefited from significant recent advances in data acquisition and computer resources. This has afforded the opportunity for routine use of heat as a tracer in a variety of hydrological regimes. Heat is particularly well suited for investigations of stream/groundwater exchanges. Dynamic temperature patterns between the stream and underlying sediments are typical, due to large stream surface area to volume ratios relative to other surface water bodies. Heat is a naturally occurring tracer, free from (real or perceived) issues of contamination associated with use of chemical tracersmore » in stream environments. The use of heat as a tracer relies on the measurement of temperature gradients, and temperature is an extremely robust parameter to monitor. Temperature data is immediately available as opposed to chemical tracers, which often require significant laboratory analysis. In this work, we report on the progress in the use of heat as a tracer to determine the hydraulic conductance of the streambed along the middle reaches of the Russian River, located west of Santa Rosa, CA. The general hydrological setting is described and the unique matter in which the water resources are managed in an environment of increasing population, a rapid shift to agricultural crops requiring more irrigation, and a series of fishery related mandates.« less
Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance.

PubMed

Garbuz, David G; Zatsepina, Olga G; Przhiboro, Andrey A; Yushenova, Irina; Guzhova, Irina V; Evgen'ev, Michael B

2008-11-01

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name 'soldier flies', occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 degrees C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.
The Global Energy Challenge

ScienceCinema

Crabtree, George

2018-01-12

The expected doubling of global energy demand by 2050 challenges our traditional patterns of energy production, distribution and use.Â Â The continued use of fossil fuels raises concerns about supply, security, environment and climate.Â New routes are needed for the efficient conversion of energy from chemical fuel, sunlight, and heat to electricity or hydrogen as an energy carrier and finally to end uses like transportation, lighting, and heating. Opportunities for efficient new energy conversion routes based on nanoscale materials will be presented, with emphasis on the sustainable energy technologies they enable.
Evaluation of Reference Genes for Normalization of Gene Expression Using Quantitative RT-PCR under Aluminum, Cadmium, and Heat Stresses in Soybean.

PubMed

Gao, Mengmeng; Liu, Yaping; Ma, Xiao; Shuai, Qin; Gai, Junyi; Li, Yan

2017-01-01

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is widely used to analyze the relative gene expression level, however, the accuracy of qRT-PCR is greatly affected by the stability of reference genes, which is tissue- and environment- dependent. Therefore, choosing the most stable reference gene in a specific tissue and environment is critical to interpret gene expression patterns. Aluminum (Al), cadmium (Cd), and heat stresses are three important abiotic factors limiting soybean (Glycine max) production in southern China. To identify the suitable reference genes for normalizing the expression levels of target genes by qRT-PCR in soybean response to Al, Cd and heat stresses, we studied the expression stability of ten commonly used housekeeping genes in soybean roots and leaves under these three abiotic stresses, using five approaches, BestKeeper, Delta Ct, geNorm, NormFinder and RefFinder. We found TUA4 is the most stable reference gene in soybean root tips under Al stress. Under Cd stress, Fbox and UKN2 are the most stable reference genes in roots and leaves, respectively, while 60S is the most suitable reference gene when analyzing both roots and leaves together. For heat stress, TUA4 and UKN2 are the most stable housekeeping genes in roots and leaves, respectively, and UKN2 is the best reference gene for analysis of roots and leaves together. To validate the reference genes, we quantified the relative expression levels of six target genes that were involved in soybean response to Al, Cd or heat stresses, respectively. The expression patterns of these target genes differed between using the most and least stable reference genes, suggesting the selection of a suitable reference gene is critical for gene expression studies.
Linking potential heat source and sink to urban heat island: Heterogeneous effects of landscape pattern on land surface temperature.

PubMed

Li, Weifeng; Cao, Qiwen; Lang, Kun; Wu, Jiansheng

2017-05-15

Rapid urbanization has significantly contributed to the development of urban heat island (UHI). Regulating landscape composition and configuration would help mitigate the UHI in megacities. Taking Shenzhen, China, as a case study area, we defined heat source and heat sink and identified strong and weak sources as well as strong and weak sinks according to the natural and socioeconomic factors influencing land surface temperature (LST). Thus, the potential thermal contributions of heat source and heat sink patches were differentiated. Then, the heterogeneous effects of landscape pattern on LST were examined by using semiparametric geographically weighted regression (SGWR) models. The results showed that landscape composition has more significant effects on thermal environment than configuration. For a strong source, the percentage of patches has a positive impact on LST. Additionally, when mosaicked with some heat sink, even a small improvement in the degree of dispersion of a strong source helps to alleviate UHI. For a weak source, the percentage and density of patches have positive impacts on LST. For a strong sink, the percentage, density, and degree of aggregation of patches have negative impacts on LST. The effects of edge density and patch shape complexity vary spatially with the fragmentation of a strong sink. Similarly, the impacts of a weak sink are mainly exerted via the characteristics of percent, density, and shape complexity of patches. Copyright © 2017 Elsevier B.V. All rights reserved.
Sweating responses during heat acclimation and moderate conditioning

NASA Technical Reports Server (NTRS)

Shvartz, E.; Bhattacharya, A.; Sperinde, S. J.; Brock, P. J.; Sciaraffa, D.; Van Beaumont, W.

1979-01-01

Experiments were conducted on ten young male subjects to determine sweating onset, distribution, and patterns as well as the relationships of these responses to body temperature during heat acclimation and moderate conditioning performed in temperate (24 C) conditions. The subjects are randomly assigned to two groups of five subjects each. The experimental period consisted of eight successive days of either graded exercise to exhaustion on a bicycle ergometer in heat (acclimation group) or in a temperate environment (control group). Major conclusions are that (1) acclimation and conditioning result in relatively more sweat rate on the limbs than on the torso, but that these changes are less related to body temperature than torso sweat rate; and (2) sweating sensitivity increases during acclimation and conditioning, but its contribution to heat acclimation is minor.
Impacts of urban landscape patterns on urban thermal variations in Guangzhou, China

NASA Astrophysics Data System (ADS)

Chen, Youjun; Yu, Shixiao

2017-02-01

One of the key impacts of rapid urbanization on the environment is the effect of surface urban thermal variations (SUTV). Understanding the effects of urban landscape features on SUTV is crucial for improving the ecology and sustainability of cities. In this study, an investigation was conducted to detect urban landscape patterns and assess their impact on surface temperature. Landsat images: Thematic Mapper was used to calculate land surface temperature (LST) in Guangzhou, the capital city of Guangdong Province in southern China. SUTV zones, including surface urban heat islands (SUHI) and surface urban heat sinks (SUHS), were then empirically identified. The composition and configuration of landscape patterns were measured by a series of spatial metrics at the class and landscape levels in the SUHI and SUHS zones. How both landscape composition and configuration influence urban thermal characteristics was then analysed. It was found that landscape composition has the strongest effect on SUTV, but that urban landscape configuration also influences SUTV. These findings are helpful for achieving a comprehensive understanding of how urban landscape patterns impact SUTV and can help in the design of effective urban landscape patterns to minimize the effects of SUHI.
Experimental Measurements of Heat Transfer through a Lunar Regolith Simulant in a Vibro-Fluidized Reactor Oven

NASA Technical Reports Server (NTRS)

Nayagam, Vedha; Berger, Gordon M.; Sacksteder, Kurt R.; Paz, Aaron

2012-01-01

Extraction of mission consumable resources such as water and oxygen from the planetary environment provides valuable reduction in launch-mass and potentially extends the mission duration. Processing of lunar regolith for resource extraction necessarily involves heating and chemical reaction of solid material with processing gases. Vibrofluidization is known to produce effective mixing and control of flow within granular media. In this study we present experimental results for vibrofluidized heat transfer in lunar regolith simulants (JSC-1 and JSC-1A) heated up to 900 C. The results show that the simulant bed height has a significant influence on the vibration induced flow field and heat transfer rates. A taller bed height leads to a two-cell circulation pattern whereas a single-cell circulation was observed for a shorter height. Lessons learned from these test results should provide insight into efficient design of future robotic missions involving In-Situ Resource Utilization.
GLOBE students, teachers, and scientists demonstrate variable differences between urban and rural leaf phenology

Treesearch

Rico Gazal; Michael A. White; Robert Gillies; Eli Rodemakers; Elena Sparrow; Leslie Gordon

2008-01-01

The urban heat island effect, classically associated with high impervious surface area (ISA), low vegetation fractional cover (Fr), and high land surface temperature (LST), has been linked to changing patterns of vegetation phenology, especially spring growth. In this study, a collaboration with the Global Learning and Observations to Benefit the Environment (GLOBE)...
Interaction between seed dormancy-release mechanism, environment and seed bank strategy for a widely distributed perennial legume, Parkinsonia aculeata (Caesalpinaceae).

PubMed

Van Klinken, Rieks D; Lukitsch, Bert; Cook, Carly

2008-08-01

Parkinsonia aculeata (Caesalpinaceae) is a perennial legume with seeds that have hard-seeded (physical) dormancy and are potentially very long-lived. Seed dormancy is a characteristic that can both help maximize the probability of seedling establishment and spread the risk of recruitment failure across years (bet-hedging). In this study, dormancy-release patterns are described across the diverse environments in which this species occurs in order to test whether wet heat (incubation under wet, warm-to-hot, conditions) alone can explain those patterns, and in order to determine the likely ecological role of physical dormancy across this species distribution. A seed burial trial was conducted across the full environmental distribution of P. aculeata in Australia (arid to wet-dry tropics, uplands to wetlands, soil surface to 10 cm deep). Wet heat explained the pattern of dormancy release across all environments. Most seeds stored in the laboratory remained dormant throughout the trial (at least 84 %). Dormancy release was quickest for seeds buried during the wet season at relatively high rainfall, upland sites (only 3 % of seeds remained dormant after 35 d). The longest-lived seeds were in wetlands (9 % remained dormant after almost 4 years) and on the soil surface (57 % after 2 years). There was no consistent correlation between increased aridity and rate of dormancy release. The results suggest that physical dormancy in P. aculeata is a mechanism for maximizing seedling establishment rather than a bet-hedging strategy. However, seed persistence can occur in environmental refuges where dormancy-release cues are weak and conditions for germination and establishment are poor (e.g. under dense vegetation or in more arid micro-environments) or unsuitable (e.g. when seeds are inundated or on the soil surface). Risks of recruitment failure in suboptimal environments could therefore be reduced by inter-year fluctuations in microclimate or seed movement.
Digital selective growth of a ZnO nanowire array by large scale laser decomposition of zinc acetate.

PubMed

Hong, Sukjoon; Yeo, Junyeob; Manorotkul, Wanit; Kang, Hyun Wook; Lee, Jinhwan; Han, Seungyong; Rho, Yoonsoo; Suh, Young Duk; Sung, Hyung Jin; Ko, Seung Hwan

2013-05-07

We develop a digital direct writing method for ZnO NW micro-patterned growth on a large scale by selective laser decomposition of zinc acetate. For ZnO NW growth, by replacing the bulk heating with the scanning focused laser as a fully digital local heat source, zinc acetate crystallites can be selectively activated as a ZnO seed pattern to grow ZnO nanowires locally on a larger area. Together with the selective laser sintering process of metal nanoparticles, more than 10,000 UV sensors have been demonstrated on a 4 cm × 4 cm glass substrate to develop all-solution processible, all-laser mask-less digital fabrication of electronic devices including active layer and metal electrodes without any conventional vacuum deposition, photolithographic process, premade mask, high temperature and vacuum environment.
Assessing the relationship between surface urban heat islands and landscape patterns across climatic zones in China.

PubMed

Yang, Qiquan; Huang, Xin; Li, Jiayi

2017-08-24

The urban heat island (UHI) effect exerts a great influence on the Earth's environment and human health and has been the subject of considerable attention. Landscape patterns are among the most important factors relevant to surface UHIs (SUHIs); however, the relationship between SUHIs and landscape patterns is poorly understood over large areas. In this study, the surface UHI intensity (SUHII) is defined as the temperature difference between urban and suburban areas, and the landscape patterns are quantified by the urban-suburban differences in several typical landscape metrics (ΔLMs). Temperature and land-cover classification datasets based on satellite observations were applied to analyze the relationship between SUHII and ΔLMs in 332 cities/city agglomerations distributed in different climatic zones of China. The results indicate that SUHII and its correlations with ΔLMs are profoundly influenced by seasonal, diurnal, and climatic factors. The impacts of different land-cover types on SUHIs are different, and the landscape patterns of the built-up and vegetation (including forest, grassland, and cultivated land) classes have the most significant effects on SUHIs. The results of this study will help us to gain a deeper understanding of the relationship between the SUHI effect and landscape patterns.
Effect of body mass and melanism on heat balance in Liolaemus lizards of the goetschi clade.

PubMed

Moreno Azócar, Débora Lina; Bonino, Marcelo Fabián; Perotti, María Gabriela; Schulte, James A; Abdala, Cristian Simón; Cruz, Félix Benjamín

2016-04-15

The body temperature of ectotherms depends on the environmental temperatures and behavioral adjustments, but morphology may also have an effect. For example, in colder environments, animals tend to be larger and to show higher thermal inertia, as proposed by Bergmann's rule and the heat balance hypothesis (HBH). Additionally, dark coloration increases solar radiation absorption and should accelerate heat gain (thermal melanism hypothesis, TMH). We tested Bergmann's rule, the HBH and the TMH within the ITALIC! Liolaemus goetschilizard clade, which shows variability in body size and melanic coloration. We measured heating and cooling rates of live and euthanized animals, and tested how morphology and color affect these rates. Live organisms show less variable and faster heating rates compared with cooling rates, suggesting behavioral and/or physiological adjustments. Our results support Bergmann's rule and the HBH, as larger species show slower heating and cooling rates. However, we did not find a clear pattern to support the TMH. The influence of dorsal melanism on heating by radiation was masked by the body size effect in live animals, and results from euthanized individuals also showed no clear effects of melanism on heating rates. Comparison among three groups of live individuals with different degrees of melanism did not clarify the influence of melanism on heating rates. However, when euthanized animals from the same three groups were compared, we observed that darker euthanized animals actually heat faster than lighter ones, favoring the TMH. Although unresolved aspects remain, body size and coloration influenced heat exchange, suggesting complex thermoregulatory strategies in these lizards, probably regulated through physiology and behavior, which may allow these small lizards to inhabit harsh weather environments. © 2016. Published by The Company of Biologists Ltd.
Polar low formation: ambient environments and the role of moisture

NASA Astrophysics Data System (ADS)

Terpstra, Annick; Spengler, Thomas; Michel, Clio; Moore, Richard

2016-04-01

Polar lows are maritime cyclones occurring during cold air outbreaks in high latitudes. Previous studies have shown that wind shear, baroclinicity, latent heat release, and surface fluxes are important factors during formation and intensification, yet their relative contributions and importance are still not fully understood. We use the ambient atmospheric conditions during polar low genesis to provide dynamical insights to the intensification and formation mechanisms for polar lows. We identify the characteristics of the ambient pre-polar low environment utilising an existing polar low database and ERA-Interim reanalysis data. Classification of these environments is based on the the direction between the thermal wind and the mean flow in the lower troposphere, where environments are classified as 'reverse shear' if the thermal wind and mean flow are in opposing directions and 'forward shear' if they are in the same direction. The two types of pre-polar low environments exhibit distinctly different features in terms of synoptic scale patterns, baroclinicity, configuration of the sea-surface temperature, as well as depth and stratification of the troposphere. These clear-cut differences hint at different dynamical pathways for the formation and intensification of polar lows for different shear environments. We also explore the role of latent heating during polar low formation utilising an idealised baroclinic channel model. The experimental design resembles a typical forward-shear moist-baroclinic environment at high-latitudes. Cyclogenesis is triggered by a weak, low-level thermal perturbation in hydrostatic and geostrophic balance. Our experiments show that significant disturbance growth is possible in absence of upper level forcing, surface fluxes, and radiation. The relative importance of diabatic versus baroclinic processes for the generation of eddy available potential energy is used to differentiate between the dynamical processes contributing to disturbance growth. The experiments indicate that sufficient latent heat release in the north-eastern quadrant of the cyclone is crucial for rapid disturbance intensification, where environmental relative humidity, baroclinicity, and static stability modulate the relative importance of latent heat release. Furthermore, the relative shallowness of the perturbation at high-latitudes increases the effectiveness of latent heat release on cyclone amplification.
Continued Water-Based Phase Change Material Heat Exchanger Development

NASA Technical Reports Server (NTRS)

Hansen, Scott; Poynot, Joe

2014-01-01

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research and experimentation to the full scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Design and construction of these HX's led to successful testing of both PCM HX's.
Heat as a tracer to determine streambed water exchanges

USGS Publications Warehouse

Constantz, J.

2010-01-01

This work reviews the use of heat as a tracer of shallow groundwater movement and describes current temperature-based approaches for estimating streambed water exchanges. Four common hydrologic conditions in stream channels are graphically depicted with the expected underlying streambed thermal responses, and techniques are discussed for installing and monitoring temperature and stage equipment for a range of hydrological environments. These techniques are divided into direct-measurement techniques in streams and streambeds, groundwater techniques relying on traditional observation wells, and remote sensing and other large-scale advanced temperatureacquisition techniques. A review of relevant literature suggests researchers often graphically visualize temperature data to enhance conceptual models of heat and water flow in the near-stream environment and to determine site-specific approaches of data analysis. Common visualizations of stream and streambed temperature patterns include thermographs, temperature envelopes, and one-, two-, and three-dimensional temperature contour plots. Heat and water transport governing equations are presented for the case of transport in streambeds, followed by methods of streambed data analysis, including simple heat-pulse arrival time and heat-loss procedures, analytical and time series solutions, and heat and water transport simulation models. A series of applications of these methods are presented for a variety of stream settings ranging from arid to continental climates. Progressive successes to quantify both streambed fluxes and the spatial extent of streambeds indicate heat-tracing tools help define the streambed as a spatially distinct field (analogous to soil science), rather than simply the lower boundary in stream research or an amorphous zone beneath the stream channel.
Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

NASA Astrophysics Data System (ADS)

Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

2016-06-01

Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

Heat shock protein expression enhances heat tolerance of reptile embryos

PubMed Central

Gao, Jing; Zhang, Wen; Dang, Wei; Mou, Yi; Gao, Yuan; Sun, Bao-Jun; Du, Wei-Guo

2014-01-01

The role of heat shock proteins (HSPs) in heat tolerance has been demonstrated in cultured cells and animal tissues, but rarely in whole organisms because of methodological difficulties associated with gene manipulation. By comparing HSP70 expression patterns among representative species of reptiles and birds, and by determining the effect of HSP70 overexpression on embryonic development and hatchling traits, we have identified the role of HSP70 in the heat tolerance of amniote embryos. Consistent with their thermal environment, and high incubation temperatures and heat tolerance, the embryos of birds have higher onset and maximum temperatures for induced HSP70 than do reptiles, and turtles have higher onset and maximum temperatures than do lizards. Interestingly, the trade-off between benefits and costs of HSP70 overexpression occurred between life-history stages: when turtle embryos developed at extreme high temperatures, HSP70 overexpression generated benefits by enhancing embryo heat tolerance and hatching success, but subsequently imposed costs by decreasing heat tolerance of surviving hatchlings. Taken together, the correlative and causal links between HSP70 and heat tolerance provide, to our knowledge, the first unequivocal evidence that HSP70 promotes thermal tolerance of embryos in oviparous amniotes. PMID:25080340
Cortisol and interleukin-6 responses during intermittent exercise in two different hot environments with equivalent WBGT.

PubMed

Wright, Heather E; McLellan, Tom M; Stapleton, Jill M; Hardcastle, Stephen G; Kenny, Glen P

2012-01-01

Blood marker concentrations such as cortisol (COR) and interleukin (IL)-6 are commonly used to evaluate the physiological strain associated with work in the heat. It is unclear, however, if hot environments of an equivalent thermal stress, as defined by a similar wet bulb globe temperature (WBGT), result in similar response patterns. This study examined markers of neuroendocrine (COR) and immune (IL-6) responses, as well as the cardiovascular and thermal responses, relative to changes in body heat content measured by whole-body direct calorimetry during work in two different hot environments with equivalent WBGT. Eight males performed a 2-hr heavy intermittent exercise protocol (six 15-min bouts of cycling at a constant rate of metabolic heat production (360W) interspersed by 5-min rest periods) in Hot/Dry (46°C, 10% relative humidity [RH]) and Warm/Humid (33°C, 60% RH) conditions (WBGT ∼ 29°C). Whole-body evaporative and dry heat exchange, change in body heat content (ΔH(b)), rectal temperature (T(re)), and heart rate were measured continuously. Venous blood was obtained at rest (PRE) and the end of each exercise bout for the measurement of changes in plasma volume (PV), plasma protein (an estimate of plasma water changes), COR, and IL-6. Ratings of perceived exertion and thermal sensation were measured during the last minute of each exercise bout. No differences existed for ΔH(b), heart rate, T(re),%ΔPV, plasma protein concentration, perceptual strain (thermal sensation, perceived exertion), and COR between the Hot/Dry and Warm/Humid conditions. IL-6 exhibited an interaction effect (p = 0.041), such that greater increases were observed in the Hot/Dry (Δ = 1.61 pg·mL(-1)) compared with the Warm/Humid (Δ = 0.64 pg·mL(-1)) environment. These findings indicate that work performed in two different hot environments with equivalent WBGT resulted in similar levels of thermal, cardiovascular, and perceptual strain, which support the use of the WBGT stress index. However, the greater IL-6 response in the Hot/Dry requires further research to elucidate the effects of different hot environments and work intensities.
Urban Thermal Environment Dynamics: A Case Study in Hangzhou During 2005-2015

NASA Astrophysics Data System (ADS)

Sun, W.; Li, F.; Yang, G.

2017-12-01

Hangzhou, as the Capital of Zhejiang Province in East China, has experienced the rapid urbanization process and associated urban heat island effect in the past twenty decades. In this study, we implemented Landsat satellite remote sensing images to investigate the relationship between landscape changes and thermal environment dynamics during 2005-2015 in Hangzhou City. A total of 48 Landsat TM/ETM+/OLR/TIRS images spanning four different seasons were downloaded from the USGS website and utilized in the study. Preprocessing works, i.e., radiometric correction and removing cloud- and fog -contaminated pixels, were conducted, and the land surface temperature (LST) was derived using the radiative transfer equation. Meanwhile, the land use and land cover (LULC) classification was accomplished by using the Support Vector Machine (SVM) classifier, and four main landscape indexes (i.e., Shannon Diversity Index, Landscape Division Index, Shannon Evenness Index, and Aggregation Index) were estimated from the LULC map. Our preliminary results show that: 1) the magnitude of urban thermal environment has obviously increased from 2005 to 2015, and the summer season shows more significant heat island effect than other three seasons; 2) the general landscape pattern of Hangzhou becomes more diversified and fragmentized from 2005 to 2015, and different landscape patterns bring that four different function zones (i.e., urban core zone, tourism function zone, industrial development zone and ecological reservation zone) of Hangzhou have different characteristics in urban thermal environment; 3) significant hot spots of LST point to the construction land while cold spots of LST coincides with the vegetation land.
Studies of Two-Phase Flow Dynamics and Heat Transfer at Reduced Gravity Conditions

NASA Technical Reports Server (NTRS)

Witte, Larry C.; Bousman, W. Scott; Fore, Larry B.

1996-01-01

The ability to predict gas-liquid flow patterns is crucial to the design and operation of two-phase flow systems in the microgravity environment. Flow pattern maps have been developed in this study which show the occurrence of flow patterns as a function of gas and liquid superficial velocities as well as tube diameter, liquid viscosity and surface tension. The results have demonstrated that the location of the bubble-slug transition is affected by the tube diameter for air-water systems and by surface tension, suggesting that turbulence-induced bubble fluctuations and coalescence mechanisms play a role in this transition. The location of the slug-annular transition on the flow pattern maps is largely unaffected by tube diameter, liquid viscosity or surface tension in the ranges tested. Void fraction-based transition criteria were developed which separate the flow patterns on the flow pattern maps with reasonable accuracy. Weber number transition criteria also show promise but further work is needed to improve these models. For annular gas-liquid flows of air-water and air- 50 percent glycerine under reduced gravity conditions, the pressure gradient agrees fairly well with a version of the Lockhart-Martinelli correlation but the measured film thickness deviates from published correlations at lower Reynolds numbers. Nusselt numbers, based on a film thickness obtained from standard normal-gravity correlations, follow the relation, Nu = A Re(sup n) Pr(exp l/3), but more experimental data in a reduced gravity environment are needed to increase the confidence in the estimated constants, A and n. In the slug flow regime, experimental pressure gradient does not correlate well with either the Lockhart-Martinelli or a homogeneous formulation, but does correlate nicely with a formulation based on a two-phase Reynolds number. Comparison with ground-based correlations implies that the heat transfer coefficients are lower at reduced gravity than at normal gravity under the same flow conditions. Nusselt numbers can be correlated in a fashion similar to Chu and Jones.
Sub-second carbon-nanotube-mediated microwave sintering for high-conductivity silver patterns on plastic substrates

NASA Astrophysics Data System (ADS)

Jung, Sunshin; Chun, Su Jin; Han, Joong Tark; Woo, Jong Seok; Shon, Cha-Hwa; Lee, Geon-Woong

2016-02-01

A method of microwave sintering that is mediated by carbon nanotubes (CNTs) has been developed to obtain high-conductivity Ag patterns on the top of heat-sensitive plastic substrates within a short time. The Ag patterns are printed on CNTs formed on plastic substrates and rapidly heated to a great extent by the heat transferred from the microwave-heated CNTs. The conductivity of the microwave-sintered Ag patterns reaches ~39% that of bulk Ag within 1 s without substrate deformation. Furthermore, microwave sintering enhances the adhesion of Ag patterns to the thermoplastic substrates because the sintering causes interfacial fusion between the Ag patterns and the substrates, and CNTs physically connect the patterns with the substrates.A method of microwave sintering that is mediated by carbon nanotubes (CNTs) has been developed to obtain high-conductivity Ag patterns on the top of heat-sensitive plastic substrates within a short time. The Ag patterns are printed on CNTs formed on plastic substrates and rapidly heated to a great extent by the heat transferred from the microwave-heated CNTs. The conductivity of the microwave-sintered Ag patterns reaches ~39% that of bulk Ag within 1 s without substrate deformation. Furthermore, microwave sintering enhances the adhesion of Ag patterns to the thermoplastic substrates because the sintering causes interfacial fusion between the Ag patterns and the substrates, and CNTs physically connect the patterns with the substrates. Electronic supplementary information (ESI) available: Temperature difference in Ag/CNT/PC samples; the carbon content and electrical performance after microwave sintering; microwave sintering of Ag/CNT patterns; physical connection between the substrate and sintered Ag lines; touch-piano (figure and movie). See DOI: 10.1039/c5nr08082g
Updated Global Patterns of Drought and Heat-Induced Forest Die-off, and Ecohydrological Feedbacks

NASA Astrophysics Data System (ADS)

Allen, C. D.

2011-12-01

Ongoing climate changes - particularly increases in mean temperatures as well as frequencies, durations, and severities of extreme drought and heat - can amplify tree physiological stress and thereby drive increases in both background tree mortality rates and episodes of rapid, broad-scale forest die-off. Updates are presented to a recent global synthesis of documented tree mortality episodes attributed to drought and/or heat, further expanding the documented spatial distribution and demonstrating the vulnerability of all major forest types from tropical moist forests and savannas to temperate and boreal forests. Given that anthropogenic climate change is projected to drive substantial increases in both mean temperatures and the frequency/duration/severity of extreme drought and heat in many regions, recent episodes of broad-scale drought-induced forest mortality may reflect increasing global risks of forest die-off, even in environments not normally considered water-limited. Since vegetation cover patterns are closely and interactively linked with ecosystem water fluxes, episodes of massive forest die-off can be expected to significantly affect ecohydrological patterns and processes, ranging from runoff and erosion to evaporation and transpiration, often with nonlinear threshold responses expected. Diverse examples of such feedbacks between climate-induced forest mortality and ecohydrology are presented, ranging from detailed observations of linked changes in vegetation, runoff, and erosion in response to forest mortality in the southwestern US to Western Australia and Amazonian rainforest water cycling. Current research efforts to address the large knowledge gaps that at present hinder our ability to predict climate-induced forest mortality and associated ecohydrological responses are discussed.
Flow Pattern Phenomena in Two-Phase Flow in Microchannels

NASA Astrophysics Data System (ADS)

Keska, Jerry K.; Simon, William E.

2004-02-01

Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results including evaluation of data acquisition techniques and their validity for application in flow pattern determination.
Switchable Underwater Bubble Wettability on Laser-Induced Titanium Multiscale Micro-/Nanostructures by Vertically Crossed Scanning.

PubMed

Jiao, Yunlong; Li, Chuanzong; Wu, Sizhu; Hu, Yanlei; Li, Jiawen; Yang, Liang; Wu, Dong; Chu, Jiaru

2018-05-16

We present here a kind of novel multiscale TiO 2 square micropillar arrays on titanium sheets through vertically crossed scanning of femtosecond laser. This multiscale micro-/nanostructure is ascribed to the combination of laser ablation/shock compression/debris self-deposition, which shows superaerophobicity in water with a very small sliding angle. The laser-induced sample displays switchable bubble wettability in water via heating in a dark environment and ultraviolet (UV) irradiation in alcohol. After heating in a dark environment (0.5 h), the ablated titanium surface shows superaerophilicity in water with a bubble contact angle (BCA) of ∼4°, which has a great ability of capturing bubbles in water. After UV irradiation in alcohol (1 h), the sample recovered its superaerophobicity in water and the BCA turns into 156°. The mechanism of reversible switching is believed as the chemical conversion between Ti-OH and Ti-O. It is worth noting that our proposed switching strategy is time-saving and the switch wetting cycle costs only 1.5 h. Then we repeat five switching cycles on the reversibility and the method shows excellent reproducibility and stability. Moreover, laser-induced samples with different scanning spacing (50-120 μm) are fabricated and all of them show switchable underwater bubble wettability via the above tunable methods. Finally, we fabricate hybrid-patterned microstructures to show different patterned bubbles in water on the heated samples. We believe the original works will provide some new insights to researchers in bubble manipulation and gas collection fields.
A new device for high-temperature in situ GISAXS measurements

NASA Astrophysics Data System (ADS)

Fritz-Popovski, Gerhard; Bodner, Sabine C.; Sosada-Ludwikowska, Florentyna; Maier, Günther A.; Morak, Roland; Chitu, Livia; Bruegemann, Lutz; Lange, Joachim; Krane, Hans-Georg; Paris, Oskar

2018-03-01

A heating stage originally designed for diffraction experiments is implemented into a Bruker NANOSTAR instrument for in situ grazing incidence small-angle x-ray scattering experiments. A controlled atmosphere is provided by a dome separating the sample environment from the evacuated scattering instrument. This dome is double shelled in order to enable cooling water to flow through it. A mesoporous silica film templated by a self-assembled block copolymer system is investigated in situ during step-wise heating in air. The GISAXS pattern shows the structural development of the ordered lattice of parallel cylindrical pores. The deformation of the elliptical pore-cross section perpendicular to the film surface was studied with increasing temperature. Moreover, the performance of the setup was tested by controlled in situ heating of a copper surface under controlled oxygen containing atmosphere.
Soil heating during wildfires and prescribed burns: a global evaluation based on existing and new data

NASA Astrophysics Data System (ADS)

Doerr, Stefan; Santin, Cristina; Reardon, James; Mataix-Solera, Jorge; Stoof, Cathelijne; Bryant, Rob; Miesel, Jessica; Badia, David

2017-04-01

Heat transfer from the combustion of ground fuels and soil organic matter during vegetation fires can cause substantial changes to the physical, chemical and biological characteristics of soils. Numerous studies have investigated the effects of wildfires and prescribed burns on soil properties based either on field samples or using laboratory experiments. Critical thresholds for changes in soil properties, however, have been determined largely based on laboratory heating experimentation. These experimental approaches have been criticized for being inadequate for reflecting the actual heating patterns soil experienced in vegetation fires, which remain poorly understood. To address this research gap, this study reviews existing and evaluates new field data on key soil heating parameters determined during wildfires and prescribed burns from a wide range of environments. The results highlight the high spatial and temporal variability in soil heating patters not only between, but also within fires. Most wildfires and prescribed burns are associated with heat pulses that are much shorter than those typically applied in laboratory studies, which can lead to erroneous conclusions when results from laboratory studies are used to predict fire impacts on soils in the field.
Heat shock protein expression enhances heat tolerance of reptile embryos.

PubMed

Gao, Jing; Zhang, Wen; Dang, Wei; Mou, Yi; Gao, Yuan; Sun, Bao-Jun; Du, Wei-Guo

2014-09-22

The role of heat shock proteins (HSPs) in heat tolerance has been demonstrated in cultured cells and animal tissues, but rarely in whole organisms because of methodological difficulties associated with gene manipulation. By comparing HSP70 expression patterns among representative species of reptiles and birds, and by determining the effect of HSP70 overexpression on embryonic development and hatchling traits, we have identified the role of HSP70 in the heat tolerance of amniote embryos. Consistent with their thermal environment, and high incubation temperatures and heat tolerance, the embryos of birds have higher onset and maximum temperatures for induced HSP70 than do reptiles, and turtles have higher onset and maximum temperatures than do lizards. Interestingly, the trade-off between benefits and costs of HSP70 overexpression occurred between life-history stages: when turtle embryos developed at extreme high temperatures, HSP70 overexpression generated benefits by enhancing embryo heat tolerance and hatching success, but subsequently imposed costs by decreasing heat tolerance of surviving hatchlings. Taken together, the correlative and causal links between HSP70 and heat tolerance provide, to our knowledge, the first unequivocal evidence that HSP70 promotes thermal tolerance of embryos in oviparous amniotes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
NLS cycle 1 and NLS 2 base heating technical notes. Appendix 3: Preliminary cycle 1 NLS base heating environments. Cycle 1 NLS base heating environments. NLS 2 650K STME base heating environments

NASA Technical Reports Server (NTRS)

Bender, Robert L.; Reardon, John E.; Prendergast, Maurice J.; Schmitz, Craig P.; Brown, John R.

1992-01-01

A preliminary analysis of National Launch System ascent plume induced base heating environments has been completed to support the Induced Environments Panel's objective to assist in maturing the NLS vehicle (1.5 stage and heavy launch lift vehicle) design. Environments during ascent have been determined from this analysis for a few selected locations on the engine nozzles and base heat shield for both vehicles. The environments reflect early summer 1991 configurations and performance data and conservative methodology. A more complete and thorough analysis is under way to update these environments for the cycle 1 review in January 1992.
In vitro burn model illustrating heat conduction patterns using compressed thermal papers.

PubMed

Lee, Jun Yong; Jung, Sung-No; Kwon, Ho

2015-01-01

To date, heat conduction from heat sources to tissue has been estimated by complex mathematical modeling. In the present study, we developed an intuitive in vitro skin burn model that illustrates heat conduction patterns inside the skin. This was composed of tightly compressed thermal papers with compression frames. Heat flow through the model left a trace by changing the color of thermal papers. These were digitized and three-dimensionally reconstituted to reproduce the heat conduction patterns in the skin. For standardization, we validated K91HG-CE thermal paper using a printout test and bivariate correlation analysis. We measured the papers' physical properties and calculated the estimated depth of heat conduction using Fourier's equation. Through contact burns of 5, 10, 15, 20, and 30 seconds on porcine skin and our burn model using a heated brass comb, and comparing the burn wound and heat conduction trace, we validated our model. The heat conduction pattern correlation analysis (intraclass correlation coefficient: 0.846, p < 0.001) and the heat conduction depth correlation analysis (intraclass correlation coefficient: 0.93, p < 0.001) showed statistically significant high correlations between the porcine burn wound and our model. Our model showed good correlation with porcine skin burn injury and replicated its heat conduction patterns. © 2014 by the Wound Healing Society.
Experimental evidence of thermal vibrational convection in a nonuniformly heated fluid in a reduced gravity environment.

PubMed

Mialdun, A; Ryzhkov, I I; Melnikov, D E; Shevtsova, V

2008-08-22

We report experimental evidence of convection caused by translational vibration of nonuniformly heated fluid in low gravity. The theory of vibrational convection in weightlessness is well developed but direct experimental proof has been missing. An innovative point of the experiment is the observation of a temperature field in the front and side views of the cubic cell. In addition, particle tracing is employed. The evolution of this field is studied systematically in a wide range of frequencies and amplitudes. The flow structures reported in previous numerical studies are confirmed. The transition from four-vortex flow to the pattern with three vortices is observed in the transient state.
Epigenetic regulation of serotype expression antagonizes transcriptome dynamics in Paramecium tetraurelia

PubMed Central

Cheaib, Miriam; Dehghani Amirabad, Azim; Nordström, Karl J. V.; Schulz, Marcel H.; Simon, Martin

2015-01-01

Phenotypic variation of a single genotype is achieved by alterations in gene expression patterns. Regulation of such alterations depends on their time scale, where short-time adaptations differ from permanently established gene expression patterns maintained by epigenetic mechanisms. In the ciliate Paramecium, serotypes were described for an epigenetically controlled gene expression pattern of an individual multigene family. Paradoxically, individual serotypes can be triggered in Paramecium by alternating environments but are then stabilized by epigenetic mechanisms, thus raising the question to which extend their expression follows environmental stimuli. To characterize environmental adaptation in the context of epigenetically controlled serotype expression, we used RNA-seq to characterize transcriptomes of serotype pure cultures. The resulting vegetative transcriptome resource is first analysed for genes involved in the adaptive response to the altered environment. Secondly, we identified groups of genes that do not follow the adaptive response but show co-regulation with the epigenetically controlled serotype system, suggesting that their gene expression pattern becomes manifested by similar mechanisms. In our experimental set-up, serotype expression and the entire group of co-regulated genes were stable among environmental changes and only heat-shock genes altered expression of these gene groups. The data suggest that the maintenance of these gene expression patterns in a lineage represents epigenetically controlled robustness counteracting short-time adaptation processes. PMID:26231545
A study of the evaporation of heterogeneous water droplets under active heating

NASA Astrophysics Data System (ADS)

Piskunov, Maxim; Legros, Jean Claude; Strizhak, Pavel

2016-11-01

Using high-speed video registration tools with a sample rate of 102-104 frames per second (fps), we studied the patterns in the evaporation of water droplets containing 1 and 2 mm individual metallic inclusions in a high-temperature gas environment. The materials of choice for the inclusions were steels (AISI 1080 carbon steel and AISI type 316L stainless steel) and pure nickel. We established the lifetimes τh of the liquid droplets under study with a controlled increase in the gas environment temperature up to 900 K. We also considered the physical aspects behind the τh distribution in the experiments conducted and specified the conditions for more effective cooling of metallic inclusions. Following the experimental research findings, a method was devised for effective reactor vessel cooling to avoid a meltdown at a nuclear power plant. The optimization of heat and mass transfer modes was performed within the framework of the strategic plan for the development of National Research Tomsk Polytechnic University as one of the world-leading universities.
Continued Water-Based Phase Change Material Heat Exchanger Development

NASA Technical Reports Server (NTRS)

Hansen, Scott W.; Sheth, Rubik B.; Poynot, Joe; Giglio, Tony; Ungar, Gene K.

2015-01-01

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to meet the full heat rejection demands. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HX's do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research on freeze front propagation to a full-scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Two units, Units A and B, were constructed and differed only in their midplate design. Both units failed multiple times during testing. This report highlights learning outcomes from these tests and are applied to a final sub-scale PCM HX which is slated to be tested on the ISS in early 2017.
Effects of Convection During the Photodeposition of Polydiacetylene Thin Films

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Hung, R. J.; Paley, M. S.; Long, Y. T.

1997-01-01

In this work, we describe a preliminary investigation of buoyancy-driven heat transfer during the growth of thin films from solution following exposure to ultraviolet (UV) light. Irradiation of the growth cell occurs at various directions relative to gravitational acceleration. Through numerical computations, the steady-state flow and temperature profiles are simulated during the course of light exposure. Light-induced polymerization accompanies a heat transfer process through a fairly complicated recirculating flow pattern. A scaling analysis shows that buoyancy-driven velocities only reduce by a factor of 10 for gravity levels as low as 10(exp -2)g(sub 0). Paley et al. observe what appears to be gravitationally sensitive particle development and inclusion in thin films using a photodeposition process. From this study it is clear that production of homogeneous thin films would have to occur in the environment of a complicated flow pattern of recirculation with a nonuniform temperature distribution. Indeed, even when irradiation occurs from the top of the cell, the most stable stratified cell orientation, defects remain in our films due to the persistence of buoyancy-driven convection. To achieve homogeneity, minimal scattering centers, and possible molecular order, photodeposition of polymer films by UV light exposure must proceed in a reduced-convection environment. Fluid mechanics simulations are useful for establishing gravitational sensitivity to this recently discovered process (patent # 5,451,433) for preparing thin films having quite promising nonlinear optical characteristics.
Effects of Convection during the Photodeposition of Polydiacetylene Thin Films

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Hung, R. J.; Paley, M. S.; Long, Y. T.

1997-01-01

In this work, we describe a preliminary investigation of buoyancy-driven heat transfer during the growth of thin films from solution following exposure to ultraviolet (UV) light. Irradiation of the growth cell occurs at various directions relative to gravitational acceleration. Through numerical computations, the steady-state flow and temperature profiles are simulated during the course of light exposure. Light-induced polymerization accompanies a heat transfer process through a fairly complicated recirculating flow pattern. A scaling analysis shows that buoyancy-driven velocities only reduce by a factor of 10 for gravity levels as low as 10(exp -2) g(sub 0). Paley et al. observe what appears to be gravitationally sensitive particle development and inclusion in thin films using a photodeposition process. From this study, it is clear that production of homogeneous thin films would have to occur in the environment of a complicated flow pattern of recirculation with a nonuniform temperature distribution. Indeed, even when irradiation occurs from the top of the cell, the most stable stratified cell orientation, defects remain in our films due to the persistence of buoyancy-driven convection. To achieve homogeneity, minimal scattering centers, and possible molecular order, photodeposition of polymer films by UV light exposure must proceed in a reduced-convection environment. Fluid mechanics simulations are useful for establishing gravitational sensitivity to this recently discovered process (patent # 5,451,433) for preparing thin films having quite promising nonlinear optical characteristics.
Environmental History Modulates Arabidopsis Pattern-Triggered Immunity in a HISTONE ACETYLTRANSFERASE1-Dependent Manner.

PubMed

Singh, Prashant; Yekondi, Shweta; Chen, Po-Wen; Tsai, Chia-Hong; Yu, Chun-Wei; Wu, Keqiang; Zimmerli, Laurent

2014-06-01

In nature, plants are exposed to a fluctuating environment, and individuals exposed to contrasting environmental factors develop different environmental histories. Whether different environmental histories alter plant responses to a current stress remains elusive. Here, we show that environmental history modulates the plant response to microbial pathogens. Arabidopsis thaliana plants exposed to repetitive heat, cold, or salt stress were more resistant to virulent bacteria than Arabidopsis grown in a more stable environment. By contrast, long-term exposure to heat, cold, or exposure to high concentrations of NaCl did not provide enhanced protection against bacteria. Enhanced resistance occurred with priming of Arabidopsis pattern-triggered immunity (PTI)-responsive genes and the potentiation of PTI-mediated callose deposition. In repetitively stress-challenged Arabidopsis, PTI-responsive genes showed enrichment for epigenetic marks associated with transcriptional activation. Upon bacterial infection, enrichment of RNA polymerase II at primed PTI marker genes was observed in environmentally challenged Arabidopsis. Finally, repetitively stress-challenged histone acetyltransferase1-1 (hac1-1) mutants failed to demonstrate enhanced resistance to bacteria, priming of PTI, and increased open chromatin states. These findings reveal that environmental history shapes the plant response to bacteria through the development of a HAC1-dependent epigenetic mark characteristic of a primed PTI response, demonstrating a mechanistic link between the primed state in plants and epigenetics. © 2014 American Society of Plant Biologists. All rights reserved.

A multi-resolution ensemble study of a tropical urban environment and its interactions with the background regional atmosphere

NASA Astrophysics Data System (ADS)

Li, Xian-Xiang; Koh, Tieh-Yong; Entekhabi, Dara; Roth, Matthias; Panda, Jagabandhu; Norford, Leslie K.

2013-09-01

This study employed the Weather Research and Forecasting model with a single-layer urban canopy model to investigate the urban environment of a tropical city, Singapore. The coupled model was evaluated against available observational data from a sensor network and flux tower. The effects of land use type and anthropogenic heat (AH) on the thermal and wind environment were investigated with a series of sensitivity tests using an ensemble approach for low advection, high convective available potential energy, intermonsoon season cases. The diurnal cycle and spatial pattern of urban heat island (UHI) intensity and planetary boundary layer height were investigated. The mean UHI intensity peaked in the early morning at 2.2°C, reaching 2.4°C in industrial areas. Sea and land breezes developed during daytime and nighttime, respectively, with the former much stronger than the latter. The model predicted that sea breezes from different coastlines of the Malay Peninsula meet and converge, inducing strong updrafts. AH was found to play roles in all the processes studied, while the effect of different land use types was most pronounced during nighttime, and least visible near noon.
Heatstroke model for desert dry-heat environment and observed organ damage.

PubMed

ou Zhou, Ren; Liu, Jiang Wei; Zhang, Dong; Zhang, Qiong

2014-06-01

Heatstroke is one of the most common clinical emergencies. Heatstroke that occurred in a dry-heat environment such as desert is usually more seriously effective and often leads to death. However, the report of the pathophysiologic mechanisms about heatstroke in dry-heat environment of desert has not been seen. Our objectives are to establish a rat model of heatstroke of dry-heat environment of desert, to assess the different degrees of damage of organ, and to preliminarily discuss the mechanism of heatstroke in dry-heat environment of desert. The first step, we have established a rat heatstroke model of dry heat environment of desert. The second step, we have accessed changes in morphology and blood indicators of heatstroke rats in dry-heat environment of desert. The heatstroke rats have expressed the changing characteristics of mean arterial pressure, core temperature, and heart rate. The organ damage changed from mild to serious level, specifically in the morphology and blood enzymology parameters such as alanine aminotransferase, aspartate aminotransferase, creatinine, urea, uric acid, creatine kinase-MB, creatine kinase, and blood gas parameters such as base excess extracellular fluid and bicarbonate ions (HCO3-). We have successfully established the rat heatstroke model of dry-heat environment of desert. We have identified heatstroke rats that presented changing characteristics on physiological indicators and varying degrees of organ damage, which are aggravated by the evolution of heatstroke in dry-heat environment of desert. We have preliminarily discussed the mechanism of heatstroke in dry-heat environment of desert. Copyright © 2014 Elsevier Inc. All rights reserved.
Neighborhood Landscape Spatial Patterns and Land Surface Temperature: An Empirical Study on Single-Family Residential Areas in Austin, Texas.

PubMed

Kim, Jun-Hyun; Gu, Donghwan; Sohn, Wonmin; Kil, Sung-Ho; Kim, Hwanyong; Lee, Dong-Kun

2016-09-02

Rapid urbanization has accelerated land use and land cover changes, and generated the urban heat island effect (UHI). Previous studies have reported positive effects of neighborhood landscapes on mitigating urban surface temperatures. However, the influence of neighborhood landscape spatial patterns on enhancing cooling effects has not yet been fully investigated. The main objective of this study was to assess the relationships between neighborhood landscape spatial patterns and land surface temperatures (LST) by using multi-regression models considering spatial autocorrelation issues. To measure the influence of neighborhood landscape spatial patterns on LST, this study analyzed neighborhood environments of 15,862 single-family houses in Austin, Texas, USA. Using aerial photos, geographic information systems (GIS), and remote sensing, FRAGSTATS was employed to calculate values of several landscape indices used to measure neighborhood landscape spatial patterns. After controlling for the spatial autocorrelation effect, results showed that larger and better-connected landscape spatial patterns were positively correlated with lower LST values in neighborhoods, while more fragmented and isolated neighborhood landscape patterns were negatively related to the reduction of LST.
Neighborhood Landscape Spatial Patterns and Land Surface Temperature: An Empirical Study on Single-Family Residential Areas in Austin, Texas

PubMed Central

Kim, Jun-Hyun; Gu, Donghwan; Sohn, Wonmin; Kil, Sung-Ho; Kim, Hwanyong; Lee, Dong-Kun

2016-01-01

Rapid urbanization has accelerated land use and land cover changes, and generated the urban heat island effect (UHI). Previous studies have reported positive effects of neighborhood landscapes on mitigating urban surface temperatures. However, the influence of neighborhood landscape spatial patterns on enhancing cooling effects has not yet been fully investigated. The main objective of this study was to assess the relationships between neighborhood landscape spatial patterns and land surface temperatures (LST) by using multi-regression models considering spatial autocorrelation issues. To measure the influence of neighborhood landscape spatial patterns on LST, this study analyzed neighborhood environments of 15,862 single-family houses in Austin, Texas, USA. Using aerial photos, geographic information systems (GIS), and remote sensing, FRAGSTATS was employed to calculate values of several landscape indices used to measure neighborhood landscape spatial patterns. After controlling for the spatial autocorrelation effect, results showed that larger and better-connected landscape spatial patterns were positively correlated with lower LST values in neighborhoods, while more fragmented and isolated neighborhood landscape patterns were negatively related to the reduction of LST. PMID:27598186
Long-term mortality experience of steelworkers. VIII. Mortality patterns of open hearth steelworkers (a preliminary report).

PubMed

Redmond, C K; Gustin, J; Kamon, E

1975-01-01

The findings in this report of a deficit in mortality from cardiovascular diseases and an excess in diseases of the digestive system among open hearth workers indicate the need for further study of men working in hot environments. In future reports we hope to refine the comparisons by obtaining data which will enable classification of workers more precisely by intensity and duration of exposure within the open hearth. Of particular importance in future work are the evaluation of possible relationships between the actual levels of heat exposure and subsequent morbidity and mortality, as well as possible interactions between heat stress and physical exertion in terms of the incidence of heart disease and other select diseases.
Designing Energy-Efficient Heat Exchangers--- Creating Micro-Channels on the Aluminum Fin Surface

NASA Astrophysics Data System (ADS)

Ying, Jia; Sommers, Andrew; Eid, Khalid

2010-03-01

In this research, a method for patterning micro-channels on aluminum surfaces is described for the purpose of exploiting those features to affect the surface wettability. Minimizing water retention on aluminum is important in the design of energy-efficient heat exchangers because water retention can deteriorate the performance of such devices. It increases the air-side pressure drop and can decrease the sensible heat transfer coefficient thereby increasing energy consumption and contributing to higher pollution levels in the environment. Photolithography is used to create the micro-scale channels and a hydrophobic polymer is used to reduce the surface energy of the aluminum plates. Droplets are both injected on the surface using a micro-syringe and condensed on the surface using an environmentally-controlled chamber. A ram'e-hart goniometer is used to determine the advancing and receding contact angles of water droplets on these modified surfaces, and a tilt-table assembly is used to measure the critical inclination angle for sliding. Our results show that droplets placed on these patterned surfaces not only have significantly lower critical inclination angles for sliding but are easier to remove from the surface at low air flow rates. Efforts to model the onset of droplet movement on these surfaces using a simple force balance relationship are currently underway.
The thermal environment of the human being on the global scale.

PubMed

Jendritzky, Gerd; Tinz, Birger

2009-11-11

The close relationship between human health, performance, well-being and the thermal environment is obvious. Nevertheless, most studies of climate and climate change impacts show amazing shortcomings in the assessment of the environment. Populations living in different climates have different susceptibilities, due to socio-economic reasons, and different customary behavioural adaptations. The global distribution of risks of hazardous thermal exposure has not been analysed before. To produce maps of the baseline and future bioclimate that allows a direct comparison of the differences in the vulnerability of populations to thermal stress across the world. The required climatological data fields are obtained from climate simulations with the global General Circulation Model ECHAM4 in T106-resolution. For the thermo-physiologically relevant assessment of these climate data a complete heat budget model of the human being, the 'Perceived Temperature' procedure has been applied which already comprises adaptation by clothing to a certain degree. Short-term physiological acclimatisation is considered via Health Related Assessment of the Thermal Environment. The global maps 1971-1980 (control run, assumed as baseline climate) show a pattern of thermal stress intensities as frequencies of heat. The heat load for people living in warm-humid climates is the highest. Climate change will lead to clear differences in health-related thermal stress between baseline climate and the future bioclimate 2041-2050 based on the 'business-as-usual' greenhouse gas scenario IS92a. The majority of the world's population will be faced with more frequent and more intense heat strain in spite of an assumed level of acclimatisation. Further adaptation measures are crucial in order to reduce the vulnerability of the populations. This bioclimatology analysis provides a tool for various questions in climate and climate change impact research. Considerations of regional or local scale require climate simulations with higher resolution. As adaptation is the key term in understanding the role of climate/climate change for human health, performance and well-being, further research in this field is crucial.
Energy exchanges in a Central Business District - Interpretation of Eddy Covariance and radiation flux measurements (London UK)

NASA Astrophysics Data System (ADS)

Kotthaus, S.; Grimmond, S.

2013-12-01

Global urbanisation brings increasingly dense and complex urban structures. To manage cities sustainably and smartly, currently and into the future under changing climates, urban climate research needs to advance in areas such as Central Business Districts (CBD) where human interactions with the environment are particularly concentrated. Measurement and modelling approaches may be pushed to their limits in dense urban settings, but if urban climate research is to contribute to the challenges of real cities those limits have to be addressed. The climate of cities is strongly governed by surface-atmosphere exchanges of energy, moisture and momentum. Observations of the relevant fluxes provide important information for improvement and evaluation of modelling approaches. Due to the CBD's heterogeneity, a very careful analysis of observations is required to understand the relevant processes. Current approaches used to interpret observations and set them in a wider context may need to be adapted for use in these more complex areas. Here, we present long-term observations of the radiation balance components and turbulent fluxes of latent heat, sensible heat and momentum in the city centre of London. This is one of the first measurement studies in a CBD covering multiple years with analysis at temporal scales from days to seasons. Data gathered at two sites in close vicinity, but with different measurement heights, are analysed to investigate the influence of source area characteristics on long-term radiation and turbulent fluxes. Challenges of source area modelling and the critical aspect of siting in such a complex environment are considered. Outgoing long- and short-wave radiation are impacted by the anisotropic nature of the urban surface and the high reflectance materials increasingly being used as building materials. Results highlight the need to consider the source area of radiometers in terms of diffuse and direct irradiance. Sensible heat fluxes (QH) are positive all year round, even at night. QH systematically exceeds input from net all-wave radiation (Q*), probably sustained by a both storage and anthropogenic heat fluxes (QF). Model estimates suggest QF can exceed the Q* nearly all year round. The positive QH inhibits stable conditions, but the stability classification is determined predominantly by the pattern of friction velocity over the rough urban surface. Turbulent latent heat flux variations are controlled (beyond the available energy) by rainfall due to the small vegetation cover. The Bowen ratio is mostly larger than one. Analysis of the eddy covariance footprint surface controls for the different land cover types by flow patterns for measurements at the two heights suggests the spatial variations of the sensible heat flux observed are partly related to changes in surface roughness, even at the local scale. Where the source areas are most homogeneous, flow conditions are vertically consistent - even if initial morphometric parameters suggested the measurements may be below the blending height. Turbulence statistics and momentum flux patterns prove useful for the interpretation of turbulent heat exchanges observed.
Epigenetic regulation of serotype expression antagonizes transcriptome dynamics in Paramecium tetraurelia.

PubMed

Cheaib, Miriam; Dehghani Amirabad, Azim; Nordström, Karl J V; Schulz, Marcel H; Simon, Martin

2015-08-01

Phenotypic variation of a single genotype is achieved by alterations in gene expression patterns. Regulation of such alterations depends on their time scale, where short-time adaptations differ from permanently established gene expression patterns maintained by epigenetic mechanisms. In the ciliate Paramecium, serotypes were described for an epigenetically controlled gene expression pattern of an individual multigene family. Paradoxically, individual serotypes can be triggered in Paramecium by alternating environments but are then stabilized by epigenetic mechanisms, thus raising the question to which extend their expression follows environmental stimuli. To characterize environmental adaptation in the context of epigenetically controlled serotype expression, we used RNA-seq to characterize transcriptomes of serotype pure cultures. The resulting vegetative transcriptome resource is first analysed for genes involved in the adaptive response to the altered environment. Secondly, we identified groups of genes that do not follow the adaptive response but show co-regulation with the epigenetically controlled serotype system, suggesting that their gene expression pattern becomes manifested by similar mechanisms. In our experimental set-up, serotype expression and the entire group of co-regulated genes were stable among environmental changes and only heat-shock genes altered expression of these gene groups. The data suggest that the maintenance of these gene expression patterns in a lineage represents epigenetically controlled robustness counteracting short-time adaptation processes. © The Author 2015. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.
The range of thermal insulation in the tissues of the new-born baby

PubMed Central

Hey, E. N.; Katz, G.

1970-01-01

1. Rectal temperature and skin temperatures were measured in twenty-eight naked babies weighing 1·1-4·5 kg, lying supine in environments of 25-31 °C when air speed was 4-7 cm/sec. The ratio of external insulation to internal or tissue insulation for the whole body averaged 2·7 but varied inversely with body weight; the ratio was higher than this on the trunk, and five times lower than this on the hand and foot. The mean ratio rose threefold when environmental temperature was increased to 34-35° C. 2. Direct measurements of heat flow from the back of a hand placed in a water jacket maintained at 32° C were made in thirty-three babies. Heat loss averaged 3 kcal/m2.hr.° C at low environmental temperature, but the loss was often rather less than this in the first 24 hr of life. Heat loss from the hand increased three- to fourfold, during exposure to an environment of 35° C. 3. When babies more than 48 hr old were exposed to an environment of 34-35° C, heat loss from the hand only increased when rectal temperature reached between 36·6 and 37·3° C; a slightly higher rectal temperature was usually reached before heat loss rose in babies less than 24 hr old. 4. Similar methods were used to study specific tissue insulation in three babies with congenital defects of the brain who lacked evidence of temperature control. No changes in insulation were detected in these three babies following changes in environmental temperature. 5. It is concluded that the range and pattern of control that can be exerted over the specific thermal insulation of the tissues is essentially the same in babies 2-20 days old as it is in adult life. PMID:5499741
Contribution of trans regulatory eQTL to cryptic genetic variation in C. elegans.

PubMed

Snoek, Basten L; Sterken, Mark G; Bevers, Roel P J; Volkers, Rita J M; Van't Hof, Arjen; Brenchley, Rachel; Riksen, Joost A G; Cossins, Andrew; Kammenga, Jan E

2017-06-29

Cryptic genetic variation (CGV) is the hidden genetic variation that can be unlocked by perturbing normal conditions. CGV can drive the emergence of novel complex phenotypes through changes in gene expression. Although our theoretical understanding of CGV has thoroughly increased over the past decade, insight into polymorphic gene expression regulation underlying CGV is scarce. Here we investigated the transcriptional architecture of CGV in response to rapid temperature changes in the nematode Caenorhabditis elegans. We analyzed regulatory variation in gene expression (and mapped eQTL) across the course of a heat stress and recovery response in a recombinant inbred population. We measured gene expression over three temperature treatments: i) control, ii) heat stress, and iii) recovery from heat stress. Compared to control, exposure to heat stress affected the transcription of 3305 genes, whereas 942 were affected in recovering animals. These affected genes were mainly involved in metabolism and reproduction. The gene expression pattern in recovering animals resembled both the control and the heat-stress treatment. We mapped eQTL using the genetic variation of the recombinant inbred population and detected 2626 genes with an eQTL in the heat-stress treatment, 1797 in the control, and 1880 in the recovery. The cis-eQTL were highly shared across treatments. A considerable fraction of the trans-eQTL (40-57%) mapped to 19 treatment specific trans-bands. In contrast to cis-eQTL, trans-eQTL were highly environment specific and thus cryptic. Approximately 67% of the trans-eQTL were only induced in a single treatment, with heat-stress showing the most unique trans-eQTL. These results illustrate the highly dynamic pattern of CGV across three different environmental conditions that can be evoked by a stress response over a relatively short time-span (2 h) and that CGV is mainly determined by response related trans regulatory eQTL.
Experimental Study of Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Aeroshell with Axisymmetric Surface Deflection Patterns

NASA Technical Reports Server (NTRS)

Hollis, Brian R.; Hollingsworth, Kevin E.

2017-01-01

A wind tunnel test program was conducted to obtain aeroheating environment data on Hypersonic Inflatable Aerodynamic Decelerator aeroshells with flexible thermal protection systems. Data were obtained on a set of rigid wind tunnel models with surface deflection patterns of various heights that simulated a range of potential in-flight aeroshell deformations. Wind tunnel testing was conducted at Mach 6 at unit Reynolds numbers from 2.1 × 10(exp 6)/ft to 8.3 × 10(exp 6)/ft and angles of attack from 0 deg to 18 deg. Boundary-layer transition onset and global surface heating distribution measurements were performed using phosphor thermography and flow field images were obtained through schlieren photography. Surface deflections were found to both promote early transition of the boundary layer and to augment heating levels for both laminar and turbulent flows. A complimentary computational flow field study was also performed to provide heating predictions for comparison with the measurements as well as boundary layer flow field properties for use in correlating the data. Correlations of the wind tunnel data were developed to predict deflection effects on boundary layer transition and surface heating and were applied to both the wind tunnel test conditions and to the trajectory of NASA's successful IRVE-3 flight test. In general, the correlations produced at least qualitative agreement with the wind tunnel data, although the heating levels were underpredicted for some of the larger surface deflections. For the flight conditions, the correlations suggested that peak heating levels on the leeward side conical flank of the IRVE-3 vehicle may have exceeded those at nose for times late in the trajectory after the peak heating time point. However, the flight estimates were based on a conservative assumption of surface deflection magnitude (i.e., larger) than likely was produced in flight.
Frequency Distribution in Domestic Microwave Ovens and Its Influence on Heating Pattern.

PubMed

Luan, Donglei; Wang, Yifen; Tang, Juming; Jain, Deepali

2017-02-01

In this study, snapshots of operating frequency profiles of domestic microwave ovens were collected to reveal the extent of microwave frequency variations under different operation conditions. A computer simulation model was developed based on the finite difference time domain method to analyze the influence of the shifting frequency on heating patterns of foods in a microwave oven. The results showed that the operating frequencies of empty and loaded domestic microwave ovens varied widely even among ovens of the same model purchased on the same date. Each microwave oven had its unique characteristic operating frequencies, which were also affected by the location and shape of the load. The simulated heating patterns of a gellan gel model food when heated on a rotary plate agreed well with the experimental results, which supported the reliability of the developed simulation model. Simulation indicated that the heating patterns of a stationary model food load changed with the varying operating frequency. However, the heating pattern of a rotary model food load was not sensitive to microwave frequencies due to the severe edge heating overshadowing the effects of the frequency variations. © 2016 Institute of Food Technologists®.
Heat Stress Effects on Growing-Finishing Swine

USDA-ARS?s Scientific Manuscript database

Understanding the factors that create heat stress, the response of the animals while under heat stress, and the signs of heat-stressed swine are essential to making rational decisions for the selection, design, and management of their environments. Heat stressors include combinations of environment...
[The evolution of heat shock genes and expression patterns of heat shock proteins in the species from temperature contrasting habitats].

PubMed

Garbuz, D G; Evgen’ev, M B

2017-01-01

Heat shock genes are the most evolutionarily ancient among the systems responsible for adaptation of organisms to a harsh environment. The encoded proteins (heat shock proteins, Hsps) represent the most important factors of adaptation to adverse environmental conditions. They serve as molecular chaperones, providing protein folding and preventing aggregation of damaged cellular proteins. Structural analysis of the heat shock genes in individuals from both phylogenetically close and very distant taxa made it possible to reveal the basic trends of the heat shock gene organization in the context of adaptation to extreme conditions. Using different model objects and nonmodel species from natural populations, it was demonstrated that modulation of the Hsps expression during adaptation to different environmental conditions could be achieved by changing the number and structural organization of heat shock genes in the genome, as well as the structure of their promoters. It was demonstrated that thermotolerant species were usually characterized by elevated levels of Hsps under normal temperature or by the increase in the synthesis of these proteins in response to heat shock. Analysis of the heat shock genes in phylogenetically distant organisms is of great interest because, on one hand, it contributes to the understanding of the molecular mechanisms of evolution of adaptogenes and, on the other hand, sheds the light on the role of different Hsps families in the development of thermotolerance and the resistance to other stress factors.
Experimental investigation on the heat transfer characteristics and flow pattern in vertical narrow channels heated from one side

NASA Astrophysics Data System (ADS)

Huang, Lihao; Li, Gang; Tao, Leren

2016-07-01

Experimental investigation for the flow boiling of water in a vertical rectangular channel was conducted to reveal the boiling heat transfer mechanism and flow patterns map aspects. The onset of nucleate boiling went upward with the increasing of the working fluid mass flow rate or the decreasing of the inlet working fluid temperature. As the vapour quality was increased, the local heat transfer coefficient increased first, then decreased, followed by various flow patterns. The test data from other researchers had a similar pattern transition for the bubble-slug flow and the slug-annular flow. Flow pattern transition model analysis was performed to make the comparison with current test data. The slug-annular and churn-annular transition models showed a close trend with current data except that the vapor phase superficial velocity of flow pattern transition was much higher than that of experimental data.
Ground based studies of thermocapillary flows in levitated drops

NASA Technical Reports Server (NTRS)

Sadhal, Satwindar Singh; Trinh, Eugene H.

1994-01-01

Analytical studies along with ground-based experiments are presently being carried out in connection with thermocapillary phenomena associated with drops and bubbles in a containerless environment. The effort here focuses on the thermal and the fluid phenomena associated with the local heating of acoustically levitated drops, both at 1-g and at low-g. In particular, the Marangoni effect on drops under conditions of local spot-heating and other types of heating are being studied. With the experiments conducted to date, fairly stable acoustic levitation of drops has been achieved and successful flow visualization by light scattering from smoke particles has been carried out. The results include situations with and without heating. As a preliminary qualitative interpretation of these experimental results, we consider the external flow pattern as a superposition of three discrete circulation cells operating on different spatial scales. The observations of the flow fields also indicate the existence of a steady state torque induced by the streaming flows. The theoretical studies have been concentrated on the analysis of streaming flows in a gaseous medium with the presence of a spherical particle undergoing periodic heating. A matched asymptotic analysis was carried out for small parameters derived from approximations in the high frequency range. The heating frequency being 'in tune' with the acoustic frequency results in a nonzero time-averaged thermal field. This leads to a steady heat flow across the equatorial plane of the sphere.
Ventilatory accommodation of oxygen demand and respiratory water loss in kangaroos from mesic and arid environments, the eastern grey kangaroo (Macropus giganteus) and the red kangaroo (Macropus rufus).

PubMed

Dawson, T J; Munn, A J; Blaney, C E; Krockenberger, A; Maloney, S K

2000-01-01

We studied ventilation in kangaroos from mesic and arid environments, the eastern grey kangaroo (Macropus giganteus) and the red kangaroo (Macropus rufus), respectively, within the range of ambient temperatures (T(a)) from -5 degrees to 45 degrees C. At thermoneutral temperatures (Ta=25 degrees C), there were no differences between the species in respiratory frequency, tidal volume, total ventilation, or oxygen extraction. The ventilatory patterns of the kangaroos were markedly different from those predicted from the allometric equation derived for placentals. The kangaroos had low respiratory frequencies and higher tidal volumes, even when adjustment was made for their lower basal metabolism. At Ta>25 degrees C, ventilation was increased in the kangaroos to facilitate respiratory water loss, with percent oxygen extraction being markedly lowered. Ventilation was via the nares; the mouth was closed. Differences in ventilation between the two species occurred at higher temperatures, and at 45 degrees C were associated with differences in respiratory evaporative heat loss, with that of M. giganteus being higher. Panting in kangaroos occurred as a graded increase in respiratory frequency, during which tidal volume was lowered. When panting, the desert red kangaroo had larger tidal volumes and lower respiratory frequencies at equivalent T(a) than the eastern grey kangaroo, which generally inhabits mesic forests. The inference made from this pattern is that the red kangaroo has the potential to increase respiratory evaporative heat loss to a greater level.
Environmental Barrier Coating Fracture, Fatigue and High-Heat-Flux Durability Modeling and Stochastic Progressive Damage Simulation

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Nemeth, Noel N.

2017-01-01

Advanced environmental barrier coatings will play an increasingly important role in future gas turbine engines because of their ability to protect emerging light-weight SiC/SiC ceramic matrix composite (CMC) engine components, further raising engine operating temperatures and performance. Because the environmental barrier coating systems are critical to the performance, reliability and durability of these hot-section ceramic engine components, a prime-reliant coating system along with established life design methodology are required for the hot-section ceramic component insertion into engine service. In this paper, we have first summarized some observations of high temperature, high-heat-flux environmental degradation and failure mechanisms of environmental barrier coating systems in laboratory simulated engine environment tests. In particular, the coating surface cracking morphologies and associated subsequent delamination mechanisms under the engine level high-heat-flux, combustion steam, and mechanical creep and fatigue loading conditions will be discussed. The EBC compostion and archtechture improvements based on advanced high heat flux environmental testing, and the modeling advances based on the integrated Finite Element Analysis Micromechanics Analysis Code/Ceramics Analysis and Reliability Evaluation of Structures (FEAMAC/CARES) program will also be highlighted. The stochastic progressive damage simulation successfully predicts mud flat damage pattern in EBCs on coated 3-D specimens, and a 2-D model of through-the-thickness cross-section. A 2-parameter Weibull distribution was assumed in characterizing the coating layer stochastic strength response and the formation of damage was therefore modeled. The damage initiation and coalescence into progressively smaller mudflat crack cells was demonstrated. A coating life prediction framework may be realized by examining the surface crack initiation and delamination propagation in conjunction with environmental degradation under high-heat-flux and environment load test conditions.
Probability of US Heat Waves Affected by a Subseasonal Planetary Wave Pattern

NASA Technical Reports Server (NTRS)

Teng, Haiyan; Branstator, Grant; Wang, Hailan; Meehl, Gerald A.; Washington, Warren M.

2013-01-01

Heat waves are thought to result from subseasonal atmospheric variability. Atmospheric phenomena driven by tropical convection, such as the Asian monsoon, have been considered potential sources of predictability on subseasonal timescales. Mid-latitude atmospheric dynamics have been considered too chaotic to allow significant prediction skill of lead times beyond the typical 10-day range of weather forecasts. Here we use a 12,000-year integration of an atmospheric general circulation model to identify a pattern of subseasonal atmospheric variability that can help improve forecast skill for heat waves in the United States. We find that heat waves tend to be preceded by 15-20 days by a pattern of anomalous atmospheric planetary waves with a wavenumber of 5. This circulation pattern can arise as a result of internal atmospheric dynamics and is not necessarily linked to tropical heating.We conclude that some mid-latitude circulation anomalies that increase the probability of heat waves are predictable beyond the typical weather forecast range.

Two novel heat-soluble protein families abundantly expressed in an anhydrobiotic tardigrade.

PubMed

Yamaguchi, Ayami; Tanaka, Sae; Yamaguchi, Shiho; Kuwahara, Hirokazu; Takamura, Chizuko; Imajoh-Ohmi, Shinobu; Horikawa, Daiki D; Toyoda, Atsushi; Katayama, Toshiaki; Arakawa, Kazuharu; Fujiyama, Asao; Kubo, Takeo; Kunieda, Takekazu

2012-01-01

Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS) and Secretory Abundant Heat Soluble (SAHS) protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals.
Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.

PubMed

Kalpathy, Sreeram K; Francis, Lorraine F; Kumar, Satish

2013-10-15

A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices. Copyright © 2013 Elsevier Inc. All rights reserved.
Thermometry, calorimetry, and mean body temperature during heat stress.

PubMed

Kenny, Glen P; Jay, Ollie

2013-10-01

Heat balance in humans is maintained at near constant levels through the adjustment of physiological mechanisms that attain a balance between the heat produced within the body and the heat lost to the environment. Heat balance is easily disturbed during changes in metabolic heat production due to physical activity and/or exposure to a warmer environment. Under such conditions, elevations of skin blood flow and sweating occur via a hypothalamic negative feedback loop to maintain an enhanced rate of dry and evaporative heat loss. Body heat storage and changes in core temperature are a direct result of a thermal imbalance between the rate of heat production and the rate of total heat dissipation to the surrounding environment. The derivation of the change in body heat content is of fundamental importance to the physiologist assessing the exposure of the human body to environmental conditions that result in thermal imbalance. It is generally accepted that the concurrent measurement of the total heat generated by the body and the total heat dissipated to the ambient environment is the most accurate means whereby the change in body heat content can be attained. However, in the absence of calorimetric methods, thermometry is often used to estimate the change in body heat content. This review examines heat exchange during challenges to heat balance associated with progressive elevations in environmental heat load and metabolic rate during exercise. Further, we evaluate the physiological responses associated with heat stress and discuss the thermal and nonthermal influences on the body's ability to dissipate heat from a heat balance perspective.
Investigating the causes and consequences of symbiont shuffling in a multi-partner reef coral symbiosis under environmental change.

PubMed

Cunning, R; Silverstein, R N; Baker, A C

2015-06-22

Dynamic symbioses may critically mediate impacts of climate change on diverse organisms, with repercussions for ecosystem persistence in some cases. On coral reefs, increases in heat-tolerant symbionts after thermal bleaching can reduce coral susceptibility to future stress. However, the relevance of this adaptive response is equivocal owing to conflicting reports of symbiont stability and change. We help reconcile this conflict by showing that change in symbiont community composition (symbiont shuffling) in Orbicella faveolata depends on the disturbance severity and recovery environment. The proportion of heat-tolerant symbionts dramatically increased following severe experimental bleaching, especially in a warmer recovery environment, but tended to decrease if bleaching was less severe. These patterns can be explained by variation in symbiont performance in the changing microenvironments created by differentially bleached host tissues. Furthermore, higher proportions of heat-tolerant symbionts linearly increased bleaching resistance but reduced photochemical efficiency, suggesting that any change in community structure oppositely impacts performance and stress tolerance. Therefore, even minor symbiont shuffling can adaptively benefit corals, although fitness effects of resulting trade-offs are difficult to predict. This work helps elucidate causes and consequences of dynamism in symbiosis, which is critical to predicting responses of multi-partner symbioses such as O. faveolata to environmental change. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Large area thermal target board: An improvement to environmental effects and system parameters characterization

NASA Astrophysics Data System (ADS)

Watkins, Wendell R.; Bean, Brent L.; Munding, Peter D.

1994-06-01

Recent field tests have provided excellent opportunities to use a new characterization tool associated with the Mobile Imaging Spectroscopy Laboratory (MISL) of the Battlefield Environment Directorate, formerly the U.S. Army Atmospheric Sciences Laboratory. The MISL large area (1.8 by 1.8 m, uniform temperature, thermal target) was used for characterization and isolation of phenomena which impact target contrast. By viewing the target board from closeup and distant ranges simultaneously with the MISL thermal imagers, the inherent scene content could be calibrated and the degrading effects of atmospheric propagation could be isolated. The target board is equipped with several spatial frequency bar patterns, but only the largest 3.5-cycle full area bar pattern was used for the distant range of 1.6 km. The quantities measured with the target board include the inherent background change, the contrast transmission, and the atmospheric modulation transfer function. The MISL target board has a unique design which makes it lightweight with near perfect transition between the hot and cold portions of the bar pattern. The heated portion of the target is an elongated rectangular even which is tilted back at a 30 deg angle to form a 1.8 by 1.8 m square when viewed from the front. The cold bars we positioned in front of the heated oven surface and can be oriented in either the vertical or horizontal direction. The oven is mounted on a lightweight trailer for one- or two-man positioning. An attached metal and canvas structure is used to shield the entire target from both solar loading and cooling winds. The target board has a thin aluminum sheet front surface which is insulated from the oven's heating structure.
Urban enhancement of the heat waves in Madrid and its metropolitan area

NASA Astrophysics Data System (ADS)

Fernandez, F.; Rasilla, D.

2009-04-01

The urban heat island (UHI) is a worldwide phenomenon that causes an increase of the temperatures in the centre of the cities. The process of urbanization has developed an intense urban heat island in Madrid, with temperature differences up to 10°C higher than the surrounding rural environment. Such differences may potentially increase the magnitude and duration of heat waves within cities, exacerbating their most negative effects over human health, particularly by night, as it deprives urban residents of the cool relief found in rural areas. In this contribution we study the long term trends on warm extreme temperature episodes in the Madrid metropolitan area, and their impact at local scale, on the onw city of Madrid. For the first task, we have compared maximum and minimum temperatures from rural (Barajas and Torrejón) and urban (El Retiro, Cuatro Vientos, Getafe) stations from 1961-2008; for the second one a local network of automated meteorological stations inside the city provided hourly data from the 2002-2004 years. Finally, the 2003 heat wave is used as an example of the spatial and temporal patterns of temperature and ozone concentrations during those extreme episodes. Our results show a regional increase in the frequency and duration of those extreme warm episodes since the end of the 80´s, although their absolute magnitude remains unchanged. The urban environment exacerbates the heat load due to the persistence of the high temperatures during the night-time hours, as it is shown by the above average number of tropical nights (> 20°C) inside the urban spaces, simultaneous to the increasing trend of maximum temperatures. Besides, the diversity of urban morphologies introduces a spatial variability on the strength of this nocturnal heat load, aggravating it in the densely urbanized areas and mitigating it in the vicinities of the green areas. The regional meteorological conditions associated to these warm episodes, characterized also by low wind speed and high values of sunshine and solar irradiation, are very favourable to increases of the levels of ozone, thus exacerbating the negative effects of the heat waves.
Genome-Wide Analysis of Yield in Europe: Allelic Effects Vary with Drought and Heat Scenarios1[OPEN

PubMed Central

Millet, Emilie J.; Welcker, Claude; Kruijer, Willem; Negro, Sandra; Coupel-Ledru, Aude; Laborde, Jacques; Bauland, Cyril; Praud, Sebastien; Presterl, Thomas; Usadel, Björn; Charcosset, Alain; Van Eeuwijk, Fred; Tardieu, François

2016-01-01

Assessing the genetic variability of plant performance under heat and drought scenarios can contribute to reduce the negative effects of climate change. We propose here an approach that consisted of (1) clustering time courses of environmental variables simulated by a crop model in current (35 years × 55 sites) and future conditions into six scenarios of temperature and water deficit as experienced by maize (Zea mays L.) plants; (2) performing 29 field experiments in contrasting conditions across Europe with 244 maize hybrids; (3) assigning individual experiments to scenarios based on environmental conditions as measured in each field experiment; frequencies of temperature scenarios in our experiments corresponded to future heat scenarios (+5°C); (4) analyzing the genetic variation of plant performance for each environmental scenario. Forty-eight quantitative trait loci (QTLs) of yield were identified by association genetics using a multi-environment multi-locus model. Eight and twelve QTLs were associated to tolerances to heat and drought stresses because they were specific to hot and dry scenarios, respectively, with low or even negative allelic effects in favorable scenarios. Twenty-four QTLs improved yield in favorable conditions but showed nonsignificant effects under stress; they were therefore associated with higher sensitivity. Our approach showed a pattern of QTL effects expressed as functions of environmental variables and scenarios, allowing us to suggest hypotheses for mechanisms and candidate genes underlying each QTL. It can be used for assessing the performance of genotypes and the contribution of genomic regions under current and future stress situations and to accelerate breeding for drought-prone environments. PMID:27436830
An investigation into the flow behavior of a single phase gas system and a two phase gas/liquid system in normal gravity with nonuniform heating from above

NASA Technical Reports Server (NTRS)

Disimile, Peter J.; Heist, Timothy J.

1990-01-01

The fluid behavior in normal gravity of a single phase gas system and a two phase gas/liquid system in an enclosed circular cylinder heated suddenly and nonuniformly from above was investigated. Flow visualization was used to obtain qualitative data on both systems. The use of thermochromatic liquid crystal particles as liquid phase flow tracers was evaluated as a possible means of simultaneously gathering both flow pattern and temperature gradient data for the two phase system. The results of the flow visualization experiments performed on both systems can be used to gain a better understanding of the behavior of such systems in a reduced gravity environment and aid in the verification of a numerical model of the system.
Near-limit flame structures at low Lewis number

NASA Technical Reports Server (NTRS)

Ronney, Paul D.

1990-01-01

The characteristics of premixed gas flames in mixtures with low Lewis numbers near flammability limits were studied experimentally using a low-gravity environment to reduce buoyant convection. The behavior of such flames was found to be dominated by diffusive-thermal instabilities. For sufficiently reactive mixtures, cellular structures resulting from these instabilities were observed and found to spawn new cells in regular patterns. For less reactive mixtures, cells formed shortly after ignition but did not spawn new cells; instead these cells evolved into a flame structure composed of stationary, apparently stable spherical flamelets. Experimental observations are found to be in qualitative agreement with elementary analytical models based on the interaction of heat release due to chemical reaction, differential diffusion of thermal energy and mass, flame front curvature, and volumetric heat losses due to gas and/or soot radiation.
The thermal environment of the human being on the global scale

PubMed Central

Jendritzky, Gerd; Tinz, Birger

2009-01-01

Background The close relationship between human health, performance, well-being and the thermal environment is obvious. Nevertheless, most studies of climate and climate change impacts show amazing shortcomings in the assessment of the environment. Populations living in different climates have different susceptibilities, due to socio-economic reasons, and different customary behavioural adaptations. The global distribution of risks of hazardous thermal exposure has not been analysed before. Objective To produce maps of the baseline and future bioclimate that allows a direct comparison of the differences in the vulnerability of populations to thermal stress across the world. Design The required climatological data fields are obtained from climate simulations with the global General Circulation Model ECHAM4 in T106-resolution. For the thermo-physiologically relevant assessment of these climate data a complete heat budget model of the human being, the ‘Perceived Temperature’ procedure has been applied which already comprises adaptation by clothing to a certain degree. Short-term physiological acclimatisation is considered via Health Related Assessment of the Thermal Environment. Results The global maps 1971–1980 (control run, assumed as baseline climate) show a pattern of thermal stress intensities as frequencies of heat. The heat load for people living in warm–humid climates is the highest. Climate change will lead to clear differences in health-related thermal stress between baseline climate and the future bioclimate 2041–2050 based on the ‘business-as-usual’ greenhouse gas scenario IS92a. The majority of the world's population will be faced with more frequent and more intense heat strain in spite of an assumed level of acclimatisation. Further adaptation measures are crucial in order to reduce the vulnerability of the populations. Conclusions This bioclimatology analysis provides a tool for various questions in climate and climate change impact research. Considerations of regional or local scale require climate simulations with higher resolution. As adaptation is the key term in understanding the role of climate/climate change for human health, performance and well-being, further research in this field is crucial. PMID:20052427
A multi-model ensemble view of winter heat flux dynamics and the dipole mode in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Liguori, Giovanni; Di Lorenzo, Emanuele; Cabos, William

2017-02-01

Changes in surface heat fluxes affect several climate processes controlling the Mediterranean climate. These include the winter formation of deep waters, which is the primary driver of the Mediterranean Sea overturning circulation. Previous studies that characterize the spatial and temporal variability of surface heat flux anomalies over the basin reveal the existence of two statistically dominant patterns of variability: a monopole of uniform sign and an east-west dipole of opposite signs. In this work, we use the 12 regional climate model ensemble from the EU-FP6 ENSEMBLES project to diagnose the large-scale atmospheric processes that control the variability of heat fluxes over the Mediterranean Sea from interannual to decadal timescales (here defined as timescales > 6 year). Our findings suggest that while the monopole structure captures variability in the winter-to-winter domain-average net heat flux, the dipole pattern tracks changes in the Mediterranean climate that are connected to the East Atlantic/Western Russia (EA/WR) atmospheric teleconnection pattern. Furthermore, while the monopole exhibits significant differences in the spatial structure across the multi-model ensemble, the dipole pattern is very robust and more clearly identifiable in the anomaly maps of individual years. A heat budget analysis of the dipole pattern reveals that changes in winds associated with the EA/WR pattern exert dominant control through both a direct effect on the latent heat flux (i.e., wind speed) and an indirect effect through specific humidity (e.g., wind advection). A simple reconstruction of the heat flux variability over the deep-water formation regions of the Gulf of Lion and the Aegean Sea reveals that the combination of the monopole and dipole time series explains over 90 % of the heat flux variance in these regions. Given the important role that surface heat flux anomalies play in deep-water formation and the regional climate, improving our knowledge on the dynamics controlling the leading modes of heat flux variability may enhance our predictability of the climate of the Mediterranean area.
Glass strengthening and patterning methods

DOEpatents

Harper, David C; Wereszczak, Andrew A; Duty, Chad E

2015-01-27

High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.
Investigation of Vapor Cooling Enhancements for Applications on Large Cryogenic Systems

NASA Technical Reports Server (NTRS)

Ameen, Lauren; Zoeckler, Joseph

2017-01-01

The need to demonstrate and evaluate the effectiveness of heat interception methods for use on a relevant cryogenic propulsion stage at a system level has been identified. Evolvable Cryogenics (eCryo) Structural Heat Intercept, Insulation and Vibration Evaluation Rig (SHIIVER) will be designed with vehicle specific geometries (SLS Exploration Upper Stage (EUS) as guidance) and will be subjected to simulated space environments. One method of reducing structure-born heat leak being investigated utilizes vapor-based heat interception. Vapor-based heat interception could potentially reduce heat leak into liquid hydrogen propulsion tanks, increasing potential mission length or payload capability. Due to the high number of unknowns associated with the heat transfer mechanism and integration of vapor-based heat interception on a realistic large-scale skirt design, a sub-scale investigation was developed. The sub-project effort is known as the Small-scale Laboratory Investigation of Cooling Enhancements (SLICE). The SLICE aims to study, design, and test sub-scale multiple attachments and flow configuration concepts for vapor-based heat interception of structural skirts. SLICE will focus on understanding the efficiency of the heat transfer mechanism to the boil-off hydrogen vapor by varying the fluid network designs and configurations. Various analyses were completed in MATLAB, Excel VBA, and COMSOL Multiphysics to understand the optimum flow pattern for heat transfer and fluid dynamics. Results from these analyses were used to design and fabricate test article subsections of a large forward skirt with vapor cooling applied. The SLICE testing is currently being performed to collect thermal mechanical performance data on multiple skirt heat removal designs while varying inlet vapor conditions necessary to intercept a specified amount of heat for a given system. Initial results suggest that applying vapor-cooling provides a 50 heat reduction in conductive heat transmission along the skirt to the tank. The information obtained by SLICE will be used by the SHIIVER engineering team to design and implement vapor-based heat removal technology into the SHIIVER forward skirt hardware design.
NASA Plum Brook's B-2 Test Facility: Thermal Vacuum and Propellant Test Facility

NASA Technical Reports Server (NTRS)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Spacecraft Propulsion Research Facility, commonly referred to as B-2, is NASA's third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of upper stage chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility. The heat sink provided a uniform temperature environment of approximately 77 K. The modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface.
Prediction of cold and heat patterns using anthropometric measures based on machine learning.

PubMed

Lee, Bum Ju; Lee, Jae Chul; Nam, Jiho; Kim, Jong Yeol

2018-01-01

To examine the association of body shape with cold and heat patterns, to determine which anthropometric measure is the best indicator for discriminating between the two patterns, and to investigate whether using a combination of measures can improve the predictive power to diagnose these patterns. Based on a total of 4,859 subjects (3,000 women and 1,859 men), statistical analyses using binary logistic regression were performed to assess the significance of the difference and the predictive power of each anthropometric measure, and binary logistic regression and Naive Bayes with the variable selection technique were used to assess the improvement in the predictive power of the patterns using the combined measures. In women, the strongest indicators for determining the cold and heat patterns among anthropometric measures were body mass index (BMI) and rib circumference; in men, the best indicator was BMI. In experiments using a combination of measures, the values of the area under the receiver operating characteristic curve in women were 0.776 by Naive Bayes and 0.772 by logistic regression, and the values in men were 0.788 by Naive Bayes and 0.779 by logistic regression. Individuals with a higher BMI have a tendency toward a heat pattern in both women and men. The use of a combination of anthropometric measures can slightly improve the diagnostic accuracy. Our findings can provide fundamental information for the diagnosis of cold and heat patterns based on body shape for personalized medicine.
Temperature Control of Hypertensive Rats during Moderate Exercise in Warm Environment.

PubMed

Campos, Helton O; Leite, Laura H R; Drummond, Lucas R; Cunha, Daise N Q; Coimbra, Cândido C; Natali, Antônio J; Prímola-Gomes, Thales N

2014-09-01

The control of body temperature in Spontaneously Hypertensive Rat (SHR) subjected to exercise in warm environment was investigated. Male SHR and Wistar rats were submitted to moderate exercise in temperate (25°C) and warm (32°C) environments while body and tail skin temperatures, as well as oxygen consumption, were registered. Total time of exercise, workload performed, mechanical efficiency and heat storage were determined. SHR had increased heat production and body temperature at the end of exercise, reduced mechanical efficiency and increased heat storage (p < 0.05). Furthermore, these rats also showed a more intense and faster increase in body temperature during moderate exercise in the warm environment (p < 0.05). The lower mechanical efficiency seen in SHR was closely correlated with their higher body temperature at the point of fatigue in warm environment (p < 0.05). Our results indicate that SHR exhibit significant differences in body temperature control during moderate exercise in warm environment characterized by increased heat production and heat storage during moderate exercise in warm environment. The combination of these responses result in aggravated hyperthermia linked with lower mechanical efficiency. Key PointsThe practice of physical exercise in warm environment has gained importance in recent decades mainly because of the progressive increases in environmental temperature;To the best of our knowledge, these is the first study to analyze body temperature control of SHR during moderate exercise in warm environment;SHR showed increased heat production and heat storage that resulted in higher body temperature at the end of exercise;SHR showed reduced mechanical efficiency;These results demonstrate that when exercising in a warm environment the hypertensive rat exhibit differences in temperature control.
Enhancement of Condensation Heat Transfer by Counter-Corrent Wavy Flow in a Vertical Tube

NASA Astrophysics Data System (ADS)

Teranishi, Tsunenobu; Ozawa, Takanori; Takimoto, Akira

As a basic research for the development of a high-performance and environment-friendly thermal energy recovery system, detailed experiments have been conducted to investigate the mechanism of the enhancement of condensation heat transfer by the counter-current moist air flow in a vertical tube. From the results of visual observation of the phenomena by using a high-speed video recorder and the measurement of condensate rate respectively from an upper and a bottom end of a cooled tube, in which various humidity vapor of air and water flowed upward or downward, the dynamic behavior of liquid film condensed on cooled surface and moist air flow was classified into four distinctive patterns in quality and quantity. Further, the effect of the scale and the operating condition such as the diameter and the length of tube, the vapor concentration and the moist air temperature, on the condensation rate of counter-current wavy flow was clarified in relation to the pattern and condition of occurrence of the wavy flow of liquid film and flooding due to the shear forces between the interface of liquid and moist air flow.
Constructal thermodynamics combined with infrared experiments to evaluate temperature differences in cells

PubMed Central

Lucia, Umberto; Grazzini, Giuseppe; Montrucchio, Bartolomeo; Grisolia, Giulia; Borchiellini, Romano; Gervino, Gianpiero; Castagnoli, Carlotta; Ponzetto, Antonio; Silvagno, Francesca

2015-01-01

The aim of this work was to evaluate differences in energy flows between normal and immortalized cells when these distinct biological systems are exposed to environmental stimulation. These differences were considered using a constructal thermodynamic approach, and were subsequently verified experimentally. The application of constructal law to cell analysis led to the conclusion that temperature differences between cells with distinct behaviour can be amplified by interaction between cells and external fields. Experimental validation of the principle was carried out on two cellular models exposed to electromagnetic fields. By infrared thermography we were able to assess small changes in heat dissipation measured as a variation in cell internal energy. The experimental data thus obtained are in agreement with the theoretical calculation, because they show a different thermal dispersion pattern when normal and immortalized cells are exposed to electromagnetic fields. By using two methods that support and validate each other, we have demonstrated that the cell/environment interaction can be exploited to enhance cell behavior differences, in particular heat dissipation. We propose infrared thermography as a technique effective in discriminating distinct patterns of thermal dispersion and therefore able to distinguish a normal phenotype from a transformed one. PMID:26100383
Constructal thermodynamics combined with infrared experiments to evaluate temperature differences in cells.

PubMed

Lucia, Umberto; Grazzini, Giuseppe; Montrucchio, Bartolomeo; Grisolia, Giulia; Borchiellini, Romano; Gervino, Gianpiero; Castagnoli, Carlotta; Ponzetto, Antonio; Silvagno, Francesca

2015-06-23

The aim of this work was to evaluate differences in energy flows between normal and immortalized cells when these distinct biological systems are exposed to environmental stimulation. These differences were considered using a constructal thermodynamic approach, and were subsequently verified experimentally. The application of constructal law to cell analysis led to the conclusion that temperature differences between cells with distinct behaviour can be amplified by interaction between cells and external fields. Experimental validation of the principle was carried out on two cellular models exposed to electromagnetic fields. By infrared thermography we were able to assess small changes in heat dissipation measured as a variation in cell internal energy. The experimental data thus obtained are in agreement with the theoretical calculation, because they show a different thermal dispersion pattern when normal and immortalized cells are exposed to electromagnetic fields. By using two methods that support and validate each other, we have demonstrated that the cell/environment interaction can be exploited to enhance cell behavior differences, in particular heat dissipation. We propose infrared thermography as a technique effective in discriminating distinct patterns of thermal dispersion and therefore able to distinguish a normal phenotype from a transformed one.
Improving Pyroelectric Energy Harvesting Using a Sandblast Etching Technique

PubMed Central

Hsiao, Chun-Ching; Siao, An-Shen

2013-01-01

Large amounts of low-grade heat are emitted by various industries and exhausted into the environment. This heat energy can be used as a free source for pyroelectric power generation. A three-dimensional pattern helps to improve the temperature variation rates in pyroelectric elements by means of lateral temperature gradients induced on the sidewalls of the responsive elements. A novel method using sandblast etching is successfully applied in fabricating the complex pattern of a vortex-like electrode. Both experiment and simulation show that the proposed design of the vortex-like electrode improved the electrical output of the pyroelectric cells and enhanced the efficiency of pyroelectric harvesting converters. A three-dimensional finite element model is generated by commercial software for solving the transient temperature fields and exploring the temperature variation rate in the PZT pyroelectric cells with various designs. The vortex-like type has a larger temperature variation rate than the fully covered type, by about 53.9%.The measured electrical output of the vortex-like electrode exhibits an obvious increase in the generated charge and the measured current, as compared to the fully covered electrode, by of about 47.1% and 53.1%, respectively. PMID:24025557

Numerical Study of Winter Diurnal Convection Over the City of Krasnoyarsk: Effects of Non-freezing River, Undulating Fog and Steam Devils

NASA Astrophysics Data System (ADS)

Hrebtov, M.; Hanjalić, K.

2017-06-01

We performed a numerical simulation of penetrative convection of an inversion-topped weakly stratified atmospheric boundary layer over urban terrain with a strong localized source of heat and moisture. With some simplifications, the case mimics the real environment of the Krasnoyarsk region in Russia where the non-freezing river Yenisei acts as a thermal and humidity source during winter, generating an undulating fog pattern along the river accompanied with scattered `steam devils'. An idealized full diurnal cycle was simulated using an unsteady Reynolds-averaged Navier-Stokes (RANS) three-equation algebraic flux model and the novel buoyancy-accounting functions for treating the ground boundary conditions. The results show a significant effect of the river on the net temperature and moisture distribution. The localized heat and moisture source leads to strong horizontal convection and marked non-uniformity of humidity concentration in the air. An interplay of several distinct large-scale vortex systems leads to a wavy pattern of moisture plumes over the river. The simulations deal with rare natural phenomena and show the capability of the RANS turbulence closure to capture the main features of flow and scalar fields on an affordable, relatively coarse, computational grid.
Southern Ocean air-sea heat flux, SST spatial anomalies, and implications for multi-decadal upper ocean heat content trends.

NASA Astrophysics Data System (ADS)

Tamsitt, V. M.; Talley, L. D.; Mazloff, M. R.

2014-12-01

The Southern Ocean displays a zonal dipole (wavenumber one) pattern in sea surface temperature (SST), with a cool zonal anomaly in the Atlantic and Indian sectors and a warm zonal anomaly in the Pacific sector, associated with the large northward excursion of the Malvinas and southeastward flow of the Antarctic Circumpolar Current (ACC). To the north of the cool Indian sector is the warm, narrow Agulhas Return Current (ARC). Air-sea heat flux is largely the inverse of this SST pattern, with ocean heat gain in the Atlantic/Indian, cooling in the southeastward-flowing ARC, and cooling in the Pacific, based on adjusted fluxes from the Southern Ocean State Estimate (SOSE), a ⅙° eddy permitting model constrained to all available in situ data. This heat flux pattern is dominated by turbulent heat loss from the ocean (latent and sensible), proportional to perturbations in the difference between SST and surface air temperature, which are maintained by ocean advection. Locally in the Indian sector, intense heat loss along the ARC is contrasted by ocean heat gain of 0.11 PW south of the ARC. The IPCC AR5 50 year depth-averaged 0-700 m temperature trend shows surprising similarities in its spatial pattern, with upper ocean warming in the ARC contrasted by cooling to the south. Using diagnosed heat budget terms from the most recent (June 2014) 6-year run of the SOSE we find that surface cooling in the ARC is balanced by heating from south-eastward advection by the current whereas heat gain in the ACC is balanced by cooling due to northward Ekman transport driven by strong westerly winds. These results suggest that spatial patterns in multi-decadal upper ocean temperature trends depend on regional variations in upper ocean dynamics.
Heating of foods in space-vehicle environments. [by conductive heat transfer

NASA Technical Reports Server (NTRS)

Bannerot, R. B.; Cox, J. E.; Chen, C. K.; Heidelbaugh, N. D.

1973-01-01

In extended space missions, foods will be heated to enhance the psychological as well as the physiological well-being of the crew. In the low-gravity space environment natural convection is essentially absent so that the heat transfer within the food is by conduction alone. To prevent boiling in reduced pressure environments the maximum temperature of the heating system is severely limited. The Skylab food-heating system utilizes a tray with receptables for the food containers. The walls of the receptacles are lined with thermally controlled, electrical-resistance, blanket-type heating elements. A finite difference model is employed to perform parametric studies on the food-heating system. The effects on heating time of the (1) thermophysical properties of the food, (2) heater power level, (3) initial food temperatures, (4) container geometry, and (5) heater control temperature are presented graphically. The optimal heater power level and container geometry are determined.
Effectiveness of exercise-heat acclimation for preventing heat illness in the workplace.

PubMed

Yamazaki, Fumio

2013-09-01

The incidence of heat-related illness in the workplace is linked to whether or not workers have acclimated to a hot environment. Heat acclimation improves endurance work performance in the heat and thermal comfort at a given work rate. These improvements are achieved by increased sweating and skin blood flow responses, better fluid balance and cardiovascular stability. As a practical means of acclimatizing the body to heat stress, daily aerobic exercise training is recommended since thermoregulatory capacity and blood volume increase with physical fitness. In workers wearing personal protective suits in hot environments, however, little psychophysiological benefit is received from short-term exercise training and/or heat acclimation because of the ineffectiveness of sweating for heat dissipation and the aggravation of thermal discomfort with the accumulation of sweat within the suit. For a manual laborer who works under uncompensable heat stress, better management of the work rate, the work environment and health is required.
Two-phase flow patterns in adiabatic and diabatic corrugated plate gaps

NASA Astrophysics Data System (ADS)

Polzin, A.-E.; Kabelac, S.; de Vries, B.

2016-09-01

Correlations for two-phase heat transfer and pressure drop can be improved considerably, when they are adapted to specific flow patterns. As plate heat exchangers find increasing application as evaporators and condensers, there is a need for flow pattern maps for corrugated plate gaps. This contribution presents experimental results on flow pattern investigations for such a plate heat exchanger background, using an adiabatic visualisation setup as well as a diabatic setup. Three characteristic flow patterns were observed in the considered range of two-phase flow: bubbly flow, film flow and slug flow. The occurrence of these flow patterns is a function of mass flux, void fraction, fluid properties and plate geometry. Two different plate geometries having a corrugation angle of 27° and 63°, respectively and two different fluids (water/air and R365mfc liquid/vapor) have been analysed. A flow pattern map using the momentum flux is presented.
The environmental genomics of metazoan thermal adaptation

PubMed Central

Porcelli, D; Butlin, R K; Gaston, K J; Joly, D; Snook, R R

2015-01-01

Continued and accelerating change in the thermal environment places an ever-greater priority on understanding how organisms are going to respond. The paradigm of ‘move, adapt or die', regarding ways in which organisms can respond to environmental stressors, stimulates intense efforts to predict the future of biodiversity. Assuming that extinction is an unpalatable outcome, researchers have focussed attention on how organisms can shift in their distribution to stay in the same thermal conditions or can stay in the same place by adapting to a changing thermal environment. How likely these respective outcomes might be depends on the answer to a fundamental evolutionary question, namely what genetic changes underpin adaptation to the thermal environment. The increasing access to and decreasing costs of next-generation sequencing (NGS) technologies, which can be applied to both model and non-model systems, provide a much-needed tool for understanding thermal adaptation. Here we consider broadly what is already known from non-NGS studies about thermal adaptation, then discuss the benefits and challenges of different NGS methodologies to add to this knowledge base. We then review published NGS genomics and transcriptomics studies of thermal adaptation to heat stress in metazoans and compare these results with previous non-NGS patterns. We conclude by summarising emerging patterns of genetic response and discussing future directions using these increasingly common techniques. PMID:25735594
Decoupled Method for Reconstruction of Surface Conditions From Internal Temperatures On Ablative Materials With Uncertain Recession Model

NASA Technical Reports Server (NTRS)

Oliver, A. Brandon

2017-01-01

Obtaining measurements of flight environments on ablative heat shields is both critical for spacecraft development and extremely challenging due to the harsh heating environment and surface recession. Thermocouples installed several millimeters below the surface are commonly used to measure the heat shield temperature response, but an ill-posed inverse heat conduction problem must be solved to reconstruct the surface heating environment from these measurements. Ablation can contribute substantially to the measurement response making solutions to the inverse problem strongly dependent on the recession model, which is often poorly characterized. To enable efficient surface reconstruction for recession model sensitivity analysis, a method for decoupling the surface recession evaluation from the inverse heat conduction problem is presented. The decoupled method is shown to provide reconstructions of equivalent accuracy to the traditional coupled method but with substantially reduced computational effort. These methods are applied to reconstruct the environments on the Mars Science Laboratory heat shield using diffusion limit and kinetically limited recession models.
Pregermination heat shock and seedling growth of fire-following Fabaceae from four Mediterranean-climate regions

NASA Astrophysics Data System (ADS)

Hanley, Mick E.; Fenner, Michael; Ne'eman, Gidi

2001-12-01

The role of heat-shock in stimulating the germination of soil-stored seeds from fire-following plant species is well known. However, the effects of high pre-germination temperatures on subsequent seedling growth are less well understood. In this study, we examined the effect of pre-germination heat shock at five temperatures (60°, 75°, 90°, 105° and 120°C, each applied for 5 min) on the seedling growth of four, fire-following Fabaceae species from four Mediterranean-type ecosystems; Hippocrepis multisiliquosa (Israel), Gastrolobium villosum (Western Australia), Cyclopia pubescens (South Africa) and Lupinus succulentus (California). Following heat treatment and subsequent germination, seedlings were grown in controlled conditions before being harvested at either 10, 20- or 40 d old. A significant increase in mean dry weight biomass was found at 10 days for Hippocrepis seedlings germinated from seeds pre-heated to 90°C. However, subsequent comparison of mean dry weight biomass for seedlings of this species at 20 and 40 d old showed no significant response to heat shock pre-treatment. Similarly, an initial increase in growth of Gastrolobium seedlings germinated from seeds heated to 90° and 105°C disappeared as the plants matured. Seedling growth of Lupinus and Cyclopia was unaffected by the pre-germination heat treatment of their seeds. Since seedling competition is influenced by the size and growth rates of neighbouring plants, any changes in seedling growth rates as a consequence of the temperature environment experienced by their seeds, may therefore influence patterns of post-fire plant community recovery.
Mapping rural community and dairy cow heat stress in Southern Ontario: A common geographic pattern from 2010 to 2012.

PubMed

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

2016-07-03

Climate change has increased the occurrence of heat waves, causing heat stress among humans and livestock, with potentially fatal consequences. Heat stress maps provide information about related health risks and insight for control strategies. Weather data were collected throughout Southern Ontario, and the heat stress index (HSI) was estimated for 2010-2012. Geostatistical kriging was applied to map heat stress, heat waves, and control periods. Average HSI for each period ranged from 55 to 78 during control periods, and from 65 to 84 during heat waves, surpassing levels where morbidity is known to increase substantially. Heat stress followed a temporally consistent geographic pattern. HSI maps indicate high-risk areas for heat-related illness and indicate areas where agriculture and human health may be at increased risk in future.
Effect of the environmental stimuli upon the human body in winter outdoor thermal environment.

PubMed

Kurazumi, Yoshihito; Kondo, Emi; Ishii, Jin; Sakoi, Tomonori; Fukagawa, Kenta; Bolashikov, Zhecho Dimitrov; Tsuchikawa, Tadahiro; Matsubara, Naoki; Horikoshi, Tetsumi

2013-01-01

In order to manage the outdoor thermal environment with regard to human health and the environmental impact of waste heat, quantitative evaluations are indispensable. It is necessary to use a thermal environment evaluation index. The purpose of this paper is to clarify the relationship between the psychological thermal responses of the human body and winter outdoor thermal environment variables. Subjective experiments were conducted in the winter outdoor environment. Environmental factors and human psychological responses were measured. The relationship between the psychological thermal responses of the human body and the outdoor thermal environment index ETFe (enhanced conduction-corrected modified effective temperature) in winter was shown. The variables which influence the thermal sensation vote of the human body are air temperature, long-wave thermal radiation and short-wave solar radiation. The variables that influence the thermal comfort vote of the human body are air temperature, humidity, short-wave solar radiation, long-wave thermal radiation, and heat conduction. Short-wave solar radiation, and heat conduction are among the winter outdoor thermal environment variables that affect psychological responses to heat. The use of thermal environment evaluation indices that comprise short-wave solar radiation and heat conduction in winter outdoor spaces is a valid approach.
Numerical investigation of the droplet condensation on the horizontal surface with patterned wettability

NASA Astrophysics Data System (ADS)

Cho, Jaeyong; Lee, Joonsang

2017-11-01

The condensation is the one of the efficient heat transfer phenomenon that transfers the heat along an interface between two phases. This condensation is affected by the wettability of surface. Heat transfer rate can be improved by controlling the wettability of surface. Recently, the researches with patterned wettability, which is composed by a combination of hydrophilic and hydrophobic surface, have been performed to improve the heat transfer rate of condensation. In this study, we performed numerical simulation for condensation of droplet on the patterned wettability, and we analyze condensation phenomenon on the wettability pattered surface through the kinetic energy, heat flux curve, and droplet shape in the vicinity of the droplet. When we performed numerical simulations and analyzing the condensation with patterned wettability, we used the lattice Boltzmann method for the base model, and phase change was solved by Peng-Robinson equation of sate. We can find that the droplet is generated at the bottom surface and high condensation rate can be maintained on the patterned wettability. This work was also supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (No. 2015R1A5A1037668) and BrainKorea21plus.
Different Temperature and Cooling Patterns at the Blunt and Sharp Egg Poles Reflect the Arrangement of Eggs in an Avian Clutch

PubMed Central

Šálek, Miroslav E.; Zárybnická, Markéta

2015-01-01

Incubation is an energetically demanding process during which birds apply heat to their eggs to ensure embryonic development. Parent behaviours such as egg turning and exchanging the outer and central eggs in the nest cup affect the amount of heat lost to the environment from individual eggs. Little is known, however, about whether and how egg surface temperature and cooling rates vary among the different areas of an egg and how the arrangement of eggs within the clutch influences heat loss. We performed laboratory (using Japanese quail eggs) and field (with northern lapwing eggs) experiments using infrared imaging to assess the temperature and cooling patterns of heated eggs and clutches. We found that (i) the sharp poles of individual quail eggs warmed to a higher egg surface temperature than did the blunt poles, resulting in faster cooling at the sharp poles compared to the blunt poles; (ii) both quail and lapwing clutches with the sharp poles oriented towards the clutch centre (arranged clutches) maintained higher temperatures over the central part of the clutch than occurred in those clutches where most of the sharp egg poles were oriented towards the exterior (scattered clutches); and (iii) the arranged clutches of both quail and lapwing showed slower cooling rates at both the inner and outer clutch positions than did the respective parts of scattered clutches. Our results demonstrate that egg surface temperature and cooling rates differ between the sharp and blunt poles of the egg and that the orientation of individual eggs within the nest cup can significantly affect cooling of the clutch as a whole. We suggest that birds can arrange their eggs within the nest cup to optimise thermoregulation of the clutch. PMID:25658846
Different temperature and cooling patterns at the blunt and sharp egg poles reflect the arrangement of eggs in an avian clutch.

PubMed

Šálek, Miroslav E; Zárybnická, Markéta

2015-01-01

Incubation is an energetically demanding process during which birds apply heat to their eggs to ensure embryonic development. Parent behaviours such as egg turning and exchanging the outer and central eggs in the nest cup affect the amount of heat lost to the environment from individual eggs. Little is known, however, about whether and how egg surface temperature and cooling rates vary among the different areas of an egg and how the arrangement of eggs within the clutch influences heat loss. We performed laboratory (using Japanese quail eggs) and field (with northern lapwing eggs) experiments using infrared imaging to assess the temperature and cooling patterns of heated eggs and clutches. We found that (i) the sharp poles of individual quail eggs warmed to a higher egg surface temperature than did the blunt poles, resulting in faster cooling at the sharp poles compared to the blunt poles; (ii) both quail and lapwing clutches with the sharp poles oriented towards the clutch centre (arranged clutches) maintained higher temperatures over the central part of the clutch than occurred in those clutches where most of the sharp egg poles were oriented towards the exterior (scattered clutches); and (iii) the arranged clutches of both quail and lapwing showed slower cooling rates at both the inner and outer clutch positions than did the respective parts of scattered clutches. Our results demonstrate that egg surface temperature and cooling rates differ between the sharp and blunt poles of the egg and that the orientation of individual eggs within the nest cup can significantly affect cooling of the clutch as a whole. We suggest that birds can arrange their eggs within the nest cup to optimise thermoregulation of the clutch.
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.
Investigation on thermal environment improvement by waste heat recovery in the underground station in Qingdao metro

NASA Astrophysics Data System (ADS)

Liu, Jianwei; Liu, Jiaquan; Wang, Fengyin; Wang, Cuiping

2018-03-01

The thermal environment parameters, like the temperature and air velocity, are measured to investigate the heat comfort status of metro staff working area in winter in Qingdao. The temperature is affected obviously by the piston wind from the train and waiting hall in the lower Hall, and the temperature is not satisfied with the least heat comfort temperature of 16 °C. At the same time, the heat produced by the electrical and control equipments is brought by the cooling air to atmosphere for the equipment safety. Utilizing the water-circulating heat pump, it is feasible to transfer the emission heat to the staff working area to improve the thermal environment. Analyzed the feasibility from the technique and economy when using the heat pump, the water-circulating heat pump could be the best way to realize the waste heat recovery and to help the heat comfort of staff working area in winter in the underground metro station in north China.
Effects of radiant heat exposure on pacing pattern during a 15-km cycling time trial.

PubMed

Levels, Koen; de Koning, Jos; Broekhuijzen, Iris; Zwaan, Tamara; Foster, Carl; Daanen, Hein

2014-01-01

The goal of this study was to investigate the effects of different durations of skin temperature manipulation on pacing patterns and performance during a 15-km cycling time trial. Nineteen well-trained men completed three 15-km cycling time trials in 18 °C and 50% relative humidity with 4.5-km (short-heat), 9.0-km (long-heat) or without (control) radiant heat exposure applied by infrared heaters after 1.5 km in the time trial. During the time trials, power output, mean skin temperature, rectal temperature, heart rate and rating of perceived exertion were assessed. The radiant heat exposure resulted in higher mean skin temperature during the time trial for short-heat (35.0 ± 0.6 °C) and long-heat (35.3 ± 0.5 °C) than for control (32.5 ± 1.0 °C; P < 0.001), whereas rectal temperature was similar (P = 0.55). The mean power output was less for short-heat (273 ± 8 W; P = 0.001) and long-heat (271 ± 9 W; P = 0.02) than for control (287 ± 7 W), but pacing patterns did not differ (P = 0.55). Heart rate was greatest in control (177 ± 9 beats · min(-1); P < 0.001), whereas the rating of perceived exertion remained similar. We concluded that a radiant heat exposure and associated higher skin temperature reduced overall performance, but did not modify pacing pattern during a 15-km cycling time trial, regardless of the duration of the exposure.
Effects of landscape composition and pattern on land surface temperature: An urban heat island study in the megacities of Southeast Asia.

PubMed

Estoque, Ronald C; Murayama, Yuji; Myint, Soe W

2017-01-15

Due to its adverse impacts on urban ecological environment and the overall livability of cities, the urban heat island (UHI) phenomenon has become a major research focus in various interrelated fields, including urban climatology, urban ecology, urban planning, and urban geography. This study sought to examine the relationship between land surface temperature (LST) and the abundance and spatial pattern of impervious surface and green space in the metropolitan areas of Bangkok (Thailand), Jakarta (Indonesia), and Manila (Philippines). Landsat-8 OLI/TIRS data and various geospatial approaches, including urban-rural gradient, multiresolution grid-based, and spatial metrics-based techniques, were used to facilitate the analysis. We found a significant strong correlation between mean LST and the density of impervious surface (positive) and green space (negative) along the urban-rural gradients of the three cities, depicting a typical UHI profile. The correlation of impervious surface density with mean LST tends to increase in larger grids, whereas the correlation of green space density with mean LST tends to increase in smaller grids, indicating a stronger influence of impervious surface and green space on the variability of LST in larger and smaller areas, respectively. The size, shape complexity, and aggregation of the patches of impervious surface and green space also had significant relationships with mean LST, though aggregation had the most consistent strong correlation. On average, the mean LST of impervious surface is about 3°C higher than that of green space, highlighting the important role of green spaces in mitigating UHI effects, an important urban ecosystem service. We recommend that the density and spatial pattern of urban impervious surfaces and green spaces be considered in landscape and urban planning so that urban areas and cities can have healthier and more comfortable living urban environments. Copyright © 2016 Elsevier B.V. All rights reserved.
Dynamos driven by weak thermal convection and heterogeneous outer boundary heat flux

NASA Astrophysics Data System (ADS)

Sahoo, Swarandeep; Sreenivasan, Binod; Amit, Hagay

2016-01-01

We use numerical dynamo models with heterogeneous core-mantle boundary (CMB) heat flux to show that lower mantle lateral thermal variability may help support a dynamo under weak thermal convection. In our reference models with homogeneous CMB heat flux, convection is either marginally supercritical or absent, always below the threshold for dynamo onset. We find that lateral CMB heat flux variations organize the flow in the core into patterns that favour the growth of an early magnetic field. Heat flux patterns symmetric about the equator produce non-reversing magnetic fields, whereas anti-symmetric patterns produce polarity reversals. Our results may explain the existence of the geodynamo prior to inner core nucleation under a tight energy budget. Furthermore, in order to sustain a strong geomagnetic field, the lower mantle thermal distribution was likely dominantly symmetric about the equator.
The thermal regime around buried submarine high-voltage cables

NASA Astrophysics Data System (ADS)

Emeana, C. J.; Hughes, T. J.; Dix, J. K.; Gernon, T. M.; Henstock, T. J.; Thompson, C. E. L.; Pilgrim, J. A.

2016-08-01

The expansion of offshore renewable energy infrastructure and the need for trans-continental shelf power transmission require the use of submarine high-voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70 °C and are typically buried 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the heat flow pattern and potential effects on the sedimentary environments around such anomalously high heat sources in the near-surface sediments are poorly understood. We present temperature measurements from a 2-D laboratory experiment representing a buried submarine HV cable, and identify the thermal regimes generated within typical unconsolidated shelf sediments—coarse silt, fine sand and very coarse sand. We used a large (2 × 2.5 m2) tank filled with water-saturated spherical glass beads (ballotini) and instrumented with a buried heat source and 120 thermocouples to measure the time-dependent 2-D temperature distributions. The observed and corresponding Finite Element Method simulations of the steady state heat flow regimes and normalized radial temperature distributions were assessed. Our results show that the heat transfer and thus temperature fields generated from submarine HV cables buried within a range of sediments are highly variable. Coarse silts are shown to be purely conductive, producing temperature increases of >10 °C up to 40 cm from the source of 60 °C above ambient; fine sands demonstrate a transition from conductive to convective heat transfer between cf. 20 and 36 °C above ambient, with >10 °C heat increases occurring over a metre from the source of 55 °C above ambient; and very coarse sands exhibit dominantly convective heat transfer even at very low (cf. 7 °C) operating temperatures and reaching temperatures of up to 18 °C above ambient at a metre from the source at surface temperatures of only 18 °C. These findings are important for the surrounding near-surface environments experiencing such high temperatures and may have significant implications for chemical and physical processes operating at the grain and subgrain scale; biological activity at both microfaunal and macrofaunal levels; and indeed the operational performance of the cables themselves, as convective heat transport would increase cable current ratings, something neglected in existing standards.
Human thermal sensation and comfort in a non-uniform environment with personalized heating.

PubMed

Deng, Qihong; Wang, Runhuai; Li, Yuguo; Miao, Yufeng; Zhao, Jinping

2017-02-01

Thermal comfort in traditionally uniform environment is apparent and can be improved by increasing energy expenses. To save energy, non-uniform environment implemented by personalized conditioning system attracts considerable attention, but human response in such environment is unclear. To investigate regional- and whole-body thermal sensation and comfort in a cool environment with personalized heating. In total 36 subjects (17 males and 19 females) including children, adults and the elderly, were involved in our experiment. Each subject was first asked to sit on a seat in an 18°C chamber (uniform environment) for 40min and then sit on a heating seat in a 16°C chamber (non-uniform environment) for another 40min after 10min break. Subjects' regional- and whole-body thermal sensation and comfort were surveyed by questionnaire and their skin temperatures were measured by wireless sensors. We statistically analyzed subjects' thermal sensation and comfort and their skin temperatures in different age and gender groups and compared them between the uniform and non-uniform environments. Overall thermal sensation and comfort votes were respectively neutral and just comfortable in 16°C chamber with personalized heating, which were significantly higher than those in 18°C chamber without heating (p<0.01). The effect of personalized heating on improving thermal sensation and comfort was consistent in subjects of different age and gender. However, adults and the females were more sensitive to the effect of personalized heating and felt cooler and less comfort than children/elderly and the males respectively. Variations of the regional thermal sensation/comfort across human body were consistent with those of skin temperature. Personalized heating significantly improved human thermal sensation and comfort in non-uniform cooler environment, probably due to the fact that it increased skin temperature. However, the link between thermal sensation/comfort and variations of skin temperature is rather complex and warrant further investigation. Copyright © 2016 Elsevier B.V. All rights reserved.

Internal flow patterns on heat transfer characteristics of a closed-loop oscillating heat-pipe with check valves using ethanol and a silver nano-ethanol mixture

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

Bhuwakietkumjohn, N.; Rittidech, S.

The aim of this research was to investigate the internal flow patterns and heat transfer characteristics of a closed-loop oscillating heat-pipe with check valves (CLOHP/CV). The ratio of number of check valves to meandering turns was 0.2. Ethanol and a silver nano-ethanol mixture were used as working fluids with a filling ratio of 50% by total volume of tube. The CLOHP/CV was made of a glass tube with an inside diameter of 2.4 mm. The evaporator section was 50 mm and 100 mm in length and there were 10 meandering turns. An inclination angle of 90 from horizontal axis wasmore » established. The evaporator section was heated by an electric heater and the condenser section was cooled by distilled water. Temperature at the evaporator section was controlled at 85 C, 105 C and 125 C. The inlet and outlet temperatures were measured. A digital camera and video camera were used to observe the flow patterns at the evaporator. The silver nano-ethanol mixture gave higher heat flux than ethanol. When the temperature at the evaporator section was increased from 85 C to 105 C and 125 C. It was found that, the flow patterns occurred as annular flow + slug flow, slug flow + bubble flow and dispersed bubble flow + bubble flow respectively. The main regime of each flow pattern can be determined from the flow pattern map ethanol and a silver nano-ethanol mixture. Each of the two working fluids gave corresponding flow patterns. (author)« less
An Investigation of the Compatibility of Radiation and Convection Heat Flux Measurements

NASA Technical Reports Server (NTRS)

Liebert, Curt H.

1996-01-01

A method for determining time-resolved absorbed surface heat flux and surface temperature in radiation and convection environments is described. The method is useful for verification of aerodynamic, heat transfer and durability models. A practical heat flux gage fabrication procedure and a simple one-dimensional inverse heat conduction model and calculation procedure are incorporated in this method. The model provides an estimate of the temperature and heat flux gradient in the direction of heat transfer through the gage. This paper discusses several successful time-resolved tests of this method in hostile convective heating and cooling environments.
Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.
A Laboratory model for the flow in urban street canyons induced by bottom heating

NASA Astrophysics Data System (ADS)

Liu, Huizhi; Liang, Bin; Zhu, Fengrong; Zhang, Boyin; Sang, Jianguo

2003-07-01

Water tank experiments are carried out to investigate the convection flow induced by bottom heating and the effects of the ambient wind on the flow in non-symmetrical urban street canyons based on the PIV (Particle Image Visualization) technique. Fluid experiments show that with calm ambient wind, the flows in the street canyon are completely driven by thermal force, and the convection can reach the upper atmosphere of the street canyon. Horizontal and vertical motions also appear above the roofs of the buildings. These are the conditions which favor the exchange of momentum and air mass between the street canyon and its environment. More than two vortices are induced by the convection, and the complex circulation pattern will vary with time in a wider street canyon. However, in a narrow street canyon, just one vortex appears. With a light ambient wind, the bottom heating and the associated convection result in just one main vortex. As the ambient wind speed increases, the vortex becomes more organized and its center shifts closer to the leeward building.
Urbanization Level and Vulnerability to Heat-Related Mortality in Jiangsu Province, China.

PubMed

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Ma, Zongwei; Liu, Yang; Huang, Lei; Bi, Jun; Kinney, Patrick L

2016-12-01

Although adverse effects of high temperature on mortality have been studied extensively in urban areas, little is known of the heat-mortality associations outside of cities. We investigated whether heat-mortality associations differed between urban and nonurban areas and how urbanicity affected the vulnerability to heat-related mortality. We first analyzed heat-related mortality risk in each of 102 counties in Jiangsu Province, China, during 2009-2013 using a distributed-lag nonlinear model. The county-specific estimates were then pooled for more urban (percentage of urban population ≥ 57.11%) and less urban (percentage of urban population < 57.11%) counties using a Bayesian hierarchical model. To explain the spatial variation in associations by county, county-level characteristics affecting heat vulnerability were also examined. We found that the overall mortality risk comparing the 99th vs. 75th percentiles of temperature was 1.43 [95% posterior intervals (PI): 1.36, 1.50] in less urban counties and 1.26 (95% PI: 1.23, 1.30) in more urban counties. The heat effects on cardiorespiratory mortality followed a similar pattern. Higher education level and prevalence of air conditioning were significantly associated with counties having lower risks, whereas percentage of elderly people was significantly associated with increased risks. Our findings reveal that nonurban areas have significant heat-related mortality risks in Jiangsu, China. These results suggest the need for enhanced adaptation planning in Chinese nonurban areas under a changing climate. Citation: Chen K, Zhou L, Chen X, Ma Z, Liu Y, Huang L, Bi J, Kinney PL. 2016. Urbanization level and vulnerability to heat-related mortality in Jiangsu Province, China. Environ Health Perspect 124:1863-1869; http://dx.doi.org/10.1289/EHP204.
Microgravity Smoldering Combustion on the USML-1 Space Shuttle Mission

NASA Technical Reports Server (NTRS)

Stocker, Dennis P.; Olson, Sandra L.; Torero, Jose L.; Fernandez-Pello, A Carlos

1994-01-01

Preliminary results from an experimental study of the smolder characteristics of a porous combustible material (flexible polyurethane foam) in normal and microgravity are presented. The experiments, limited in fuel sample size and power available for ignition, show that the smolder process was primarily controlled by heat losses from the reaction to the surrounding environment. In microgravity, the reduced heat losses due to the absence of natural convection result in only slightly higher temperatures in the quiescent microgravity test than in normal gravity but a dramatically larger production of combustion products in all microgravity tests. Particularly significant is the proportionately larger amount of carbon monoxide and light organic compounds produced in microgravity, despite comparable temperatures and similar char patterns. This excessive production of fuel-rich combustion products may be a generic characteristic of smoldering polyurethane in microgravity, with an associated increase in the toxic hazard of smolder in spacecraft.
Microgravity smoldering combustion on the USML-1 Space Shuttle mission

NASA Technical Reports Server (NTRS)

Stocker, Dennis P.; Olson, Sandra L.; Torero, Jose L.; Fernandez-Pello, A. Carlos

1995-01-01

Preliminary results from an experimental study of the smolder characteristics of a porous combustible material (flexible polyurethane foam) in normal and microgravity are presented. The experiments, limited in fuel sample size and power available for ignition, show that the smolder process was primarily controlled by heat losses from the reaction to the surrounding environment In microgravity, the reduced heat losses due to the absence of natural convection result in only slightly higher temperatures in the quiescent microgravity test than in normal gravity, but a dramatically larger production of combustion products in all microgravity tests. Particularly significant is the proportionately larger amount of carbon monoxide and light organic compounds produced in microgravity, despite comparable temperatures and similar char patterns. This excessive production of fuel-rich combustion products may be a generic characteristic of smoldering polyurethane in microgravity, with an associated increase in the toxic hazard of smolder in spacecraft.
Marginal effects of a large caffeine dose on heat balance during exercise-heat stress.

PubMed

Ely, Brett R; Ely, Matthew R; Cheuvront, Samuel N

2011-02-01

The use of caffeine supplements in athletic and military populations has increased in recent years. Excessive caffeine consumption in conjunction with exercise in a hot environment may predispose individuals to heat illness. To examine heat balance induced by a large dose of caffeine during exercise in a hot environment. Ten men, not heat acclimated and not habitual caffeine users, consumed either caffeine (CAF; 9 mg/kg) or placebo (PLA) before performing cycle-ergometer exercise for 30 min at 50% VO2peak in a 40 °C, 25% relative humidity environment while body temperature (core and skin) and ratings of thermal comfort (TC) were monitored. Heat-exchange variables were calculated using partitional calorimetry and thermometry. Mean body temperature (Tb) was higher (p < .05) with CAF (37.18 ± 0.15 °C) than with PLA (36.93 ± 0.15 °C) at the start of exercise. Heat production was slightly higher (~8 W, p < .05) with CAF. There were no differences in heat storage, dry heat gains, TC, or Tb during exercise. A caffeine dose of 9 mg/kg does not appreciably alter heat balance during work in a hot environment. The small increase in Tb observed with CAF was undetected by the participants and is unlikely to increase physiological strain sufficiently to affect endurance performance or risk of heat illness.
Transcriptional profile of breast muscle in heat stressed layers is similar to that of broiler chickens at control temperature.

PubMed

Zahoor, Imran; de Koning, Dirk-Jan; Hocking, Paul M

2017-09-20

In recent years, the commercial importance of changes in muscle function of broiler chickens and of the corresponding effects on meat quality has increased. Furthermore, broilers are more sensitive to heat stress during transport and at high ambient temperatures than smaller egg-laying chickens. We hypothesised that heat stress would amplify muscle damage and expression of genes that are involved in such changes and, thus, lead to the identification of pathways and networks associated with broiler muscle and meat quality traits. Broiler and layer chickens were exposed to control or high ambient temperatures to characterise differences in gene expression between the two genotypes and the two environments. Whole-genome expression studies in breast muscles of broiler and layer chickens were conducted before and after heat stress; 2213 differentially-expressed genes were detected based on a significant (P < 0.05) genotype × treatment interaction. This gene set was analysed with the BioLayout Express 3D and Ingenuity Pathway Analysis software and relevant biological pathways and networks were identified. Genes involved in functions related to inflammatory reactions, cell death, oxidative stress and tissue damage were upregulated in control broilers compared with control and heat-stressed layers. Expression of these genes was further increased in heat-stressed broilers. Differences in gene expression between broiler and layer chickens under control and heat stress conditions suggest that damage of breast muscles in broilers at normal ambient temperatures is similar to that in heat-stressed layers and is amplified when broilers are exposed to heat stress. The patterns of gene expression of the two genotypes under heat stress were almost the polar opposite of each other, which is consistent with the conclusion that broiler chickens were not able to cope with heat stress by dissipating their body heat. The differentially expressed gene networks and pathways were consistent with the pathological changes that are observed in the breast muscle of heat-stressed broilers.
Hsp70 expression in thermally stressed Ostrea edulis, a commercially important oyster in Europe

PubMed Central

Piano, Annamaria; Asirelli, Christian; Caselli, Federico; Fabbri, Elena

2002-01-01

Synthesis of heat shock proteins (Hsps) in response to elevated temperatures and other denaturing agents is a common feature of prokaryotic and eukaryotic cells. The heat-induced expression of Hsp70 family members in the gills and mantle of Ostrea edulis, a highly valued fisheries resource inhabiting primarily estuarine environments, has been studied. O edulis is exposed to a variety of natural and anthropogenic stresses in the environment. Two isoforms of about 72 kDa and 77 kDa were constitutively present in unstressed organisms, reflecting the housekeeping function performed by these proteins under normal circumstances. Their expression in animals undergoing thermal stress was highly variable, and on the average, little change occurred under different experimental conditions. A third isoform of about 69 kDa was induced in both tissues after exposure to ≥32°C; its synthesis was detected within 4 hours of poststress recovery at 15°C, reaching the maximum expression after 24 hours in the gills and after 48 hours in the mantle and declining thereafter. Hsp69 expression was low at 38°C, a temperature lethal for about 50% of the individuals tested. Densitometric analysis of Western blots revealed that Hsp69 was mostly responsible for the significant heat-induced overexpression of Hsp70s in O edulis. Comparison with heat shock responses in tissues of Crassostrea gigas indicated a similar pattern of Hsp70 expression. In this organism, however, Hsp69 was induced after exposure to ≥38°C. We conclude that tissue expression of Hsp69 in O edulis, and possibly other bivalves, is an early sign of thermal stress; determining whether these changes also correlate with other major environmental stresses is the goal of ongoing studies. PMID:12482201
[Malfunction simulation by spaceflight training simulator].

PubMed

Chang, Tian-chun; Zhang, Lian-hua; Xue, Liang; Lian, Shun-guo

2005-04-01

To implement malfunction simulation in spaceflight training simulator. The principle of malfunction simulation was defined according to spacecraft malfunction predict and its countermeasures. The malfunction patterns were classified, and malfunction type was confirmed. A malfunction simulation model was established, and the malfunction simulation was realized by math simulation. According to the requirement of astronaut training, a spacecraft subsystem malfunction simulation model was established and realized, such as environment control and life support, GNC, push, power supply, heat control, data management, measure control and communication, structure and so on. The malfunction simulation function implemented in the spaceflight training simulator satisfied the requirements for astronaut training.
Data mining of space heating system performance in affordable housing

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

Ren, Xiaoxin; Yan, Da; Hong, Tianzhen

The space heating in residential buildings accounts for a considerable amount of the primary energy use. Therefore, understanding the operation and performance of space heating systems becomes crucial in improving occupant comfort while reducing energy use. This study investigated the behavior of occupants adjusting their thermostat settings and heating system operations in a 62-unit affordable housing complex in Revere, Massachusetts, USA. The data mining methods, including clustering approach and decision trees, were used to ascertain occupant behavior patterns. Data tabulating ON/OFF space heating states was assessed, to provide a better understanding of the intermittent operation of space heating systems inmore » terms of system cycling frequency and the duration of each operation. The decision tree was used to verify the link between room temperature settings, house and heating system characteristics and the heating energy use. The results suggest that the majority of apartments show fairly constant room temperature profiles with limited variations during a day or between weekday and weekend. Data clustering results revealed six typical patterns of room temperature profiles during the heating season. Space heating systems cycled more frequently than anticipated due to a tight range of room thermostat settings and potentially oversized heating capacities. In conclusion, from this study affirm data mining techniques are an effective method to analyze large datasets and extract hidden patterns to inform design and improve operations.« less
Data mining of space heating system performance in affordable housing

DOE PAGES

Ren, Xiaoxin; Yan, Da; Hong, Tianzhen

2015-02-16

The space heating in residential buildings accounts for a considerable amount of the primary energy use. Therefore, understanding the operation and performance of space heating systems becomes crucial in improving occupant comfort while reducing energy use. This study investigated the behavior of occupants adjusting their thermostat settings and heating system operations in a 62-unit affordable housing complex in Revere, Massachusetts, USA. The data mining methods, including clustering approach and decision trees, were used to ascertain occupant behavior patterns. Data tabulating ON/OFF space heating states was assessed, to provide a better understanding of the intermittent operation of space heating systems inmore » terms of system cycling frequency and the duration of each operation. The decision tree was used to verify the link between room temperature settings, house and heating system characteristics and the heating energy use. The results suggest that the majority of apartments show fairly constant room temperature profiles with limited variations during a day or between weekday and weekend. Data clustering results revealed six typical patterns of room temperature profiles during the heating season. Space heating systems cycled more frequently than anticipated due to a tight range of room thermostat settings and potentially oversized heating capacities. In conclusion, from this study affirm data mining techniques are an effective method to analyze large datasets and extract hidden patterns to inform design and improve operations.« less
Aerothermodynamic Design of the Mars Science Laboratory Backshell and Parachute Cone

NASA Technical Reports Server (NTRS)

Edquist, Karl T.; Dyakonov, Artem A.; Wright, Michael J.; Tang, Chun Y.

2009-01-01

Aerothermodynamic design environments are presented for the Mars Science Laboratory entry capsule backshell and parachute cone. The design conditions are based on Navier-Stokes flowfield simulations on shallow (maximum total heat load) and steep (maximum heat flux) design entry trajectories from a 2009 launch. Transient interference effects from reaction control system thruster plumes were included in the design environments when necessary. The limiting backshell design heating conditions of 6.3 W/sq cm for heat flux and 377 J/sq cm for total heat load are not influenced by thruster firings. Similarly, the thrusters do not affect the parachute cover lid design environments (13 W/sq cm and 499 J/sq cm). If thruster jet firings occur near peak dynamic pressure, they will augment the design environments at the interface between the backshell and parachute cone (7 W/sq cm and 174 J/sq cm). Localized heat fluxes are higher near the thruster fairing during jet firings, but these areas did not require additional thermal protection material. Finally, heating bump factors were developed for antenna radomes on the parachute cone
Effect of the Environmental Stimuli upon the Human Body in Winter Outdoor Thermal Environment

PubMed Central

Kurazumi, Yoshihito; Kondo, Emi; Ishii, Jin; Sakoi, Tomonori; Fukagawa, Kenta; Bolashikov, Zhecho Dimitrov; Tsuchikawa, Tadahiro; Matsubara, Naoki; Horikoshi, Tetsumi

2013-01-01

In order to manage the outdoor thermal environment with regard to human health and the environmental impact of waste heat, quantitative evaluations are indispensable. It is necessary to use a thermal environment evaluation index. The purpose of this paper is to clarify the relationship between the psychological thermal responses of the human body and winter outdoor thermal environment variables. Subjective experiments were conducted in the winter outdoor environment. Environmental factors and human psychological responses were measured. The relationship between the psychological thermal responses of the human body and the outdoor thermal environment index ETFe (enhanced conduction-corrected modified effective temperature) in winter was shown. The variables which influence the thermal sensation vote of the human body are air temperature, long-wave thermal radiation and short-wave solar radiation. The variables that influence the thermal comfort vote of the human body are air temperature, humidity, short-wave solar radiation, long-wave thermal radiation, and heat conduction. Short-wave solar radiation, and heat conduction are among the winter outdoor thermal environment variables that affect psychological responses to heat. The use of thermal environment evaluation indices that comprise short-wave solar radiation and heat conduction in winter outdoor spaces is a valid approach. PMID:23861691
Heat exposure in the Canadian workplace.

PubMed

Jay, Ollie; Kenny, Glen P

2010-08-01

Exposure to excessive heat is a physical hazard that threatens Canadian workers. As patterns of global climate change suggest an increased frequency of heat waves, the potential impact of these extreme climate events on the health and well-being of the Canadian workforce is a new and growing challenge. Increasingly, industries rely on available technology and information to ensure the safety of their workers. Current Canadian labor codes in all provinces employ the guidelines recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) that are Threshold Limit Values (TLVs) based upon Wet Bulb Globe Temperature (WBGT). The TLVs are set so that core body temperature of the workers supposedly does not exceed 38.0 degrees C. Legislation in most Canadian provinces also requires employers to install engineering and administrative controls to reduce the heat stress risk of their working environment should it exceed the levels permissible under the WBGT system. There are however severe limitations using the WGBT system because it only directly evaluates the environmental parameters and merely incorporates personal factors such as clothing insulation and metabolic heat production through simple correction factors for broadly generalized groups. An improved awareness of the strengths and limitations of TLVs and the WGBT index can minimize preventable measurement errors and improve their utilization in workplaces. Work is on-going, particularly in the European Union to develop an improved individualized heat stress risk assessment tool. More work is required to improve the predictive capacity of these indices. Copyright 2010 Wiley-Liss, Inc.
Small heat-shock proteins and leaf cooling capacity account for the unusual heat tolerance of the central spike leaves in Agave tequilana var. Weber.

PubMed

Luján, Rosario; Lledías, Fernando; Martínez, Luz María; Barreto, Rita; Cassab, Gladys I; Nieto-Sotelo, Jorge

2009-12-01

Agaves are perennial crassulacean acid metabolism (CAM) plants distributed in tropical and subtropical arid environments, features that are attractive for studying the heat-shock response. In agaves, the stress response can be analysed easily during leaf development, as they form a spirally shaped rosette, having the meristem surrounded by folded leaves in the centre (spike) and the unfolded and more mature leaves in the periphery. Here, we report that the spike of Agave tequilana is the most thermotolerant part of the rosette withstanding shocks of up to 55 degrees C. This finding was inconsistent with the patterns of heat-shock protein (Hsp) gene expression, as maximal accumulation of Hsp transcripts was at 44 degrees C in all sectors (spike, inner, middle and outer). However, levels of small HSP (sHSP)-CI and sHSP-CII proteins were conspicuously higher in spike leaves at all temperatures correlating with their thermotolerance. In addition, spike leaves showed a higher stomatal density and abated more efficiently their temperature several degrees below that of air. We propose that the greater capacity for leaf cooling during the day in response to heat stress, and the elevated levels of sHSPs, constitute part of a set of strategies that protect the SAM and folded leaves of A. tequilana from high temperatures.
Two-phase flow patterns of a top heat mode closed loop oscillating heat pipe with check valves (THMCLOHP/CV)

NASA Astrophysics Data System (ADS)

Thongdaeng, S.; Bubphachot, B.; Rittidech, S.

2016-11-01

This research is aimed at studying the two-phase flow pattern of a top heat mode closed loop oscillating heat pipe with check valves. The working fluids used are ethanol and R141b and R11 coolants with a filling ratio of 50% of the total volume. It is found that the maximum heat flux occurs for the R11 coolant used as the working fluid in the case with the inner diameter of 1.8 mm, inclination angle of -90°, evaporator temperature of 125°C, and evaporator length of 50 mm. The internal flow patterns are found to be slug flow/disperse bubble flow/annular flow, slug flow/disperse bubble flow/churn flow, slug flow/bubble flow/annular flow, slug flow/disperse bubble flow, bubble flow/annular flow, and slug flow/annular flow.
Method for measuring residual stresses in materials by plastically deforming the material and interference pattern comparison

DOEpatents

Pechersky, Martin J.

1995-01-01

A method for measuring residual stress in a material comprising the steps of establishing a speckle pattern on the surface with a first laser then heating a portion of that pattern with an infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress dung heating and enables calculation of the stress.
Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature

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

Miyagi, Lowell; Department of Earth Sciences, Montana State University, Bozeman, Montana 59717; Kanitpanyacharoen, Waruntorn

2013-02-15

To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate andmore » optimize conditions for combined resistive and laser heating. For example, in Run1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg{sub 0.9}Fe{sub 0.1})O in Run3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.« less

Warm vegetarians? Heat waves and diet shifts in tadpoles.

PubMed

Carreira, B M; Segurado, P; Orizaola, G; Gonçalves, N; Pinto, V; Laurila, A; Rebelo, R

2016-11-01

Temperature can play an important role in determining the feeding preferences of ectotherms. In light of the warmer temperatures arising with the current climatic changes, omnivorous ectotherms may perform diet shifts toward higher herbivory to optimize energetic intake. Such diet shifts may also occur during heat waves, which are projected to become more frequent, intense, and longer lasting in the future. Here, we investigated how heat waves of different duration affect feeding preferences in omnivorous anuran tadpoles and how these choices affect larval life history. In laboratory experiments, we fed tadpoles of three species on animal, plant, or mixed diet and exposed them to short heat waves (similar to the heat waves these species experience currently) or long heat waves (predicted to increase under climate change). We estimated the dietary choices of tadpoles fed on the mixed diet using stable isotopes and recorded tadpole survival and growth, larval period, and mass at metamorphosis. Tadpole feeding preferences were associated with their thermal background, with herbivory increasing with breeding temperature in nature. Patterns in survival, growth, and development generally support decreased efficiency of carnivorous diets and increased efficiency or higher relative quality of herbivorous diets at higher temperatures. All three species increased herbivory in at least one of the heat wave treatments, but the responses varied among species. Diet shifts toward higher herbivory were maladaptive in one species, but beneficial in the other two. Higher herbivory in omnivorous ectotherms under warmer temperatures may impact species differently and further contribute to changes in the structure and function of freshwater environments. © 2016 by the Ecological Society of America.
Visualization of natural convection heat transfer on a sphere

NASA Astrophysics Data System (ADS)

Lee, Dong-Young; Chung, Bum-Jin

2017-12-01

Natural convection heat transfer phenomena on spheres were investigated by adopting mass transfer experiments based on analogy concept. The diameters of spheres were varied from 0.01 m to 0.12 m, which correspond to the Rayleigh numbers of 1.69×108-2.91×1011. The measured mass transfer coefficients agreed well with the existing correlations. The copper electroplating patterns on the spheres visualized the local heat transfer depending on angular distance. The streak plating patterns were observed on the upper part of the sphere, resulting from the wavy flow patterns caused by the instability.
Non-coaxial-based microwave ablation antennas for creating symmetric and asymmetric coagulation zones

NASA Astrophysics Data System (ADS)

Mohtashami, Yahya; Luyen, Hung; Hagness, Susan C.; Behdad, Nader

2018-06-01

We present an investigation of a new class of microwave ablation (MWA) antennas capable of producing axially symmetric or asymmetric heating patterns. The antenna design is based on a dipole fed by a balanced parallel-wire transmission line. The angle and direction of the deployed dipole arms are used to control the heating pattern. We analyzed the specific absorption rate and temperature profiles using electromagnetic and thermal simulations. Two prototypes were fabricated and tested in ex vivo ablation experiments: one was designed to produce symmetric heating patterns and the other was designed to generate asymmetric heating patterns. Both fabricated prototypes exhibited good impedance matching and produced localized coagulation zones as predicted by the simulations. The prototype operating in porcine muscle created an ˜10 cm3 symmetric ablation zone after 10 min of ablation with a power level of 18 W. The prototype operating in egg white created an ˜4 cm3 asymmetric ablation zone with a directionality ratio of 40% after 5 min of ablation with a power level of 25 W. The proposed MWA antenna design shows promise for minimally invasive treatment of tumors in various clinical scenarios where, depending on the situation, a symmetric or an asymmetric heating pattern may be needed.
Characterizing Spatial and Temporal Patterns of Thermal Environment and Air Quality in Taipei Metropolitan Area

NASA Astrophysics Data System (ADS)

Juang, J. Y.; Sun, C. H.; Jiang, J. A.; Wen, T. H.

2017-12-01

The urban heat island effect (UHI) caused by the regional-to-global environmental changes, dramatic urbanization, and shifting in land-use compositions has becoming an important environmental issue in recent years. In the past century, the coverage of urban area in Taipei Basin has dramatically increasing by ten folds. The strengthen of UHI effect significantly enhances the frequency of warm-night effect, and strongly influences the thermal environment of the residents in the Greater Taipei Metropolitan. In addition, the urban expansions due to dramatic increasing in urban populations and traffic loading significantly impacts the air quality and causes health issue in Taipei. In this study, the main objective is to quantify and characterize the temporal and spatial distributions of thermal environmental and air quality in the Greater Taipei Metropolitan Area by using monitoring data from Central Weather Bureau, Environmental Protection Administration. In addition, in this study, we conduct the analysis on the distribution of physiological equivalent temperature in the micro scale in the metropolitan area by using the observation data and quantitative simulation to investigate how the thermal environment is influenced under different conditions. Furthermore, we establish a real-time mobile monitoring system by using wireless sensor network to investigate the correlation between the thermal environment, air quality and other environmental factors, and propose to develop the early warning system for heat stress and air quality in the metropolitan area. The results from this study can be integrated into the management and planning system, and provide sufficient and important background information for the development of smart city in the metropolitan area in the future.
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.
Comparative and Combinative Study of Urban Heat island in Wuhan City with Remote Sensing and CFD Simulation

PubMed Central

Li, Kun; Yu, Zhuang

2008-01-01

Urban heat islands are one of the most critical urban environment heat problems. Landsat ETM+ satellite data were used to investigate the land surface temperature and underlying surface indices such as NDVI and NDBI. A comparative study of the urban heat environment at different scales, times and locations was done to verify the heat island characteristics. Since remote sensing technology has limitations for dynamic flow analysis in the study of urban spaces, a CFD simulation was used to validate the improvement of the heat environment in a city by means of wind. CFD technology has its own shortcomings in parameter setting and verification, while RS technology is helpful to remedy this. The city of Wuhan and its climatological condition of being hot in summer and cold in winter were chosen to verify the comparative and combinative application of RS with CFD in studying the urban heat island. PMID:27873893
Analytical study of the heat loss attenuation by clothing on thermal manikins under radiative heat loads.

PubMed

Den Hartog, Emiel A; Havenith, George

2010-01-01

For wearers of protective clothing in radiation environments there are no quantitative guidelines available for the effect of a radiative heat load on heat exchange. Under the European Union funded project ThermProtect an analytical effort was defined to address the issue of radiative heat load while wearing protective clothing. As within the ThermProtect project much information has become available from thermal manikin experiments in thermal radiation environments, these sets of experimental data are used to verify the analytical approach. The analytical approach provided a good prediction of the heat loss in the manikin experiments, 95% of the variance was explained by the model. The model has not yet been validated at high radiative heat loads and neglects some physical properties of the radiation emissivity. Still, the analytical approach provides a pragmatic approach and may be useful for practical implementation in protective clothing standards for moderate thermal radiation environments.
Pool-Boiling Heat-Transfer Enhancement on Cylindrical Surfaces with Hybrid Wettable Patterns.

PubMed

Kumar C S, Sujith; Chang, Yao Wen; Chen, Ping-Hei

2017-04-10

In this study, pool-boiling heat-transfer experiments were performed to investigate the effect of the number of interlines and the orientation of the hybrid wettable pattern. Hybrid wettable patterns were produced by coating superhydrophilic SiO2 on a masked, hydrophobic, cylindrical copper surface. Using de-ionized (DI) water as the working fluid, pool-boiling heat-transfer studies were conducted on the different surface-treated copper cylinders of a 25-mm diameter and a 40-mm length. The experimental results showed that the number of interlines and the orientation of the hybrid wettable pattern influenced the wall superheat and the HTC. By increasing the number of interlines, the HTC was enhanced when compared to the plain surface. Images obtained from the charge-coupled device (CCD) camera indicated that more bubbles formed on the interlines as compared to other parts. The hybrid wettable pattern with the lowermost section being hydrophobic gave the best heat-transfer coefficient (HTC). The experimental results indicated that the bubble dynamics of the surface is an important factor that determines the nucleate boiling.
Temperature regulation of bud-burst phenology within and among years in a young Douglas-fir (Pseudotsuga menziesii) plantation in western Washington, USA.

PubMed

Bailey, John D; Harrington, Constance A

2006-04-01

Past research has established that terminal buds of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings from many seed sources have a chilling requirement of about 1200 h at 0-5 degrees C; once chilled, temperatures > 5 degrees C force bud burst via accumulation of heat units. We tested this sequential bud-burst model in the field to determine whether terminal buds of trees in cooler microsites, which receive less heat forcing, develop more slowly than those in warmer microsites. For three years we monitored terminal bud development in young saplings as well as soil and air temperatures on large, replicated plots in a harvest unit; plots differed in microclimate based on amount of harvest residue and shade from neighboring stands. In two of three years, trees on cooler microsites broke bud 2 to 4 days earlier than those on warmer microsites, despite receiving less heat forcing from March to May each year. A simple sequential model did not predict cooler sites having earlier bud burst nor did it correctly predict the order of bud burst across the three years. We modified the basic heat-forcing model to initialize, or reset to zero, the accumulation of heat units whenever significant freezing temperature events (> or = 3 degree-hours day(-1) < 0 degrees C) occurred; this modified model correctly predicted the sequence of bud burst across years. Soil temperature alone or in combination with air temperature did not improve our predictions of bud burst. Past models of bud burst have relied heavily on data from controlled experiments with simple temperature patterns; analysis of more variable temperature patterns from our 3-year field trial, however, indicated that simple models of bud burst are inaccurate. More complex models that incorporate chilling hours, heat forcing, photoperiod and the occurrence of freeze events in the spring may be needed to predict effects of future silvicultural treatments as well to interpret the implications of climate-change scenarios. Developing and testing new models will require data from both field and controlled-environment experiments.
Optimal joule heating of the subsurface

DOEpatents

Berryman, James G.; Daily, William D.

1994-01-01

A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.
A mechanistic model of heat transfer for gas-liquid flow in vertical wellbore annuli.

PubMed

Yin, Bang-Tang; Li, Xiang-Fang; Liu, Gang

2018-01-01

The most prominent aspect of multiphase flow is the variation in the physical distribution of the phases in the flow conduit known as the flow pattern. Several different flow patterns can exist under different flow conditions which have significant effects on liquid holdup, pressure gradient and heat transfer. Gas-liquid two-phase flow in an annulus can be found in a variety of practical situations. In high rate oil and gas production, it may be beneficial to flow fluids vertically through the annulus configuration between well tubing and casing. The flow patterns in annuli are different from pipe flow. There are both casing and tubing liquid films in slug flow and annular flow in the annulus. Multiphase heat transfer depends on the hydrodynamic behavior of the flow. There are very limited research results that can be found in the open literature for multiphase heat transfer in wellbore annuli. A mechanistic model of multiphase heat transfer is developed for different flow patterns of upward gas-liquid flow in vertical annuli. The required local flow parameters are predicted by use of the hydraulic model of steady-state multiphase flow in wellbore annuli recently developed by Yin et al. The modified heat-transfer model for single gas or liquid flow is verified by comparison with Manabe's experimental results. For different flow patterns, it is compared with modified unified Zhang et al. model based on representative diameters.
Design and Modeling of a Variable Heat Rejection Radiator

NASA Technical Reports Server (NTRS)

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

2011-01-01

Variable Heat Rejection Radiator technology needed for future NASA human rated & robotic missions Primary objective is to enable a single loop architecture for human-rated missions (1) Radiators are typically sized for maximum heat load in the warmest continuous environment resulting in a large panel area (2) Large radiator area results in fluid being susceptible to freezing at low load in cold environment and typically results in a two-loop system (3) Dual loop architecture is approximately 18% heavier than single loop architecture (based on Orion thermal control system mass) (4) Single loop architecture requires adaptability to varying environments and heat loads
Asymmetric Base-Bleed Effect on Aerospike Plume-Induced Base-Heating Environment

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Droege, Alan; DAgostino, Mark; Lee, Young-Ching; Williams, Robert

2004-01-01

A computational heat transfer design methodology was developed to study the dual-engine linear aerospike plume-induced base-heating environment during one power-pack out, in ascent flight. It includes a three-dimensional, finite volume, viscous, chemically reacting, and pressure-based computational fluid dynamics formulation, a special base-bleed boundary condition, and a three-dimensional, finite volume, and spectral-line-based weighted-sum-of-gray-gases absorption computational radiation heat transfer formulation. A separate radiation model was used for diagnostic purposes. The computational methodology was systematically benchmarked. In this study, near-base radiative heat fluxes were computed, and they compared well with those measured during static linear aerospike engine tests. The base-heating environment of 18 trajectory points selected from three power-pack out scenarios was computed. The computed asymmetric base-heating physics were analyzed. The power-pack out condition has the most impact on convective base heating when it happens early in flight. The source of its impact comes from the asymmetric and reduced base bleed.
Investigation of the heating behavior of carbide-bonded graphene coated silicon wafer used for hot embossing

NASA Astrophysics Data System (ADS)

Yang, Gao; Li, Lihua; Lee, Wing Bun; Ng, Man Cheung; Chan, Chang Yuen

2018-03-01

A recently developed carbide-bonded graphene (CBG) coated silicon wafer was found to be an effective micro-patterned mold material for implementing rapid heating in hot embossing processes owing to its superior electrical and thermal conductivity, in addition to excellent mechanical properties. To facilitate the achievement of precision temperature control in the hot embossing, the heating behavior of a CBG coated silicon wafer sample was experimentally investigated. First, two groups of controlled experiments were conducted for quantitatively evaluating the influence of the main factors such as the vacuum pressure and gaseous environment (vacuum versus nitrogen) on its heating performance. The electrical and thermal responses of this sample under a voltage of 60 V were then intensively analyzed, and revealed that it had somewhat semi-conducting properties. Further, we compared its thermal profiles under different settings of the input voltage and current limiting threshold. Moreover, the strong temperature dependence of electrical resistance for this material was observed and determined. Ultimately, the surface temperature of CBG coated silicon wafer could be as high as 1300 ℃, but surprisingly the graphene coating did not detach from the substrate under such an elevated temperature due to its strong thermal coupling with the silicon wafer.
Changes in heat waves indices in Romania over the period 1961-2015

NASA Astrophysics Data System (ADS)

Croitoru, Adina-Eliza; Piticar, Adrian; Ciupertea, Antoniu-Flavius; Roşca, Cristina Florina

2016-11-01

In the last two decades many climate change studies have focused on extreme temperatures as they have a significant impact on environment and society. Among the weather events generated by extreme temperatures, heat waves are some of the most harmful. The main objective of this study was to detect and analyze changes in heat waves in Romania based on daily observation data (maximum and minimum temperature) over the extended summer period (May-Sept) using a set of 10 indices and to explore the spatial patterns of changes. Heat wave data series were derived from daily maximum and minimum temperature data sets recorded in 29 weather stations across Romania over a 55-year period (1961-2015). In this study, the threshold chosen was the 90th percentile calculated based on a 15-day window centered on each calendar day, and for three baseline periods (1961-1990, 1971-2000, and 1981-2010). Two heat wave definitions were considered: at least three consecutive days when maximum temperature exceeds 90th percentile, and at least three consecutive days when minimum temperature exceeds 90th percentile. For each of them, five variables were calculated: amplitude, magnitude, number of events, duration, and frequency. Finally, 10 indices resulted for further analysis. The main results are: most of the indices have statistically significant increasing trends; only one index for one weather station indicated statistically significant decreasing trend; the changes are more intense in case of heat waves detected based on maximum temperature compared to those obtained for heat waves identified based on minimum temperature; western and central regions of Romania are the most exposed to increasing heat waves.
Reusable high-temperature heat pipes and heat pipe panels

NASA Technical Reports Server (NTRS)

Camarda, Charles J. (Inventor); Ransone, Philip O. (Inventor)

1989-01-01

A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.
Method of coating an iron-based article

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

Magdefrau, Neal; Beals, James T.; Sun, Ellen Y.

A method of coating an iron-based article includes a first heating step of heating a substrate that includes an iron-based material in the presence of an aluminum source material and halide diffusion activator. The heating is conducted in a substantially non-oxidizing environment, to cause the formation of an aluminum-rich layer in the iron-based material. In a second heating step, the substrate that has the aluminum-rich layer is heated in an oxidizing environment to oxidize the aluminum in the aluminum-rich layer.
Experimental investigation of heat transfer and flow pattern from heated horizontal rectangular fin array under natural convection

NASA Astrophysics Data System (ADS)

Taji, S. G.; Parishwad, G. V.; Sane, N. K.

2014-07-01

This paper presents results of the experimental study conducted on heated horizontal rectangular fin array under natural convection. The temperature mapping and the prediction of the flow patterns over the fin array with variable fin spacing is carried out. Dimensionless fin spacing to height (S/H) ratio is varied from 0.05 to 0.3 and length to height ratio (L/H) = 5 is kept constant. The heater input to the fin array assembly is varied from 25 to 100 W. The single chimney flow pattern is observed from 8 to 12 mm fin spacing. The end flow is choked below 6 mm fin spacing. The single chimney flow pattern changes to sliding or end flow choking at 6 mm fin spacing. The average heat transfer coefficient (ha) is very small (2.52-5.78 W/m2 K) at 100 W for S = 5-12 mm. The ha is very small (1.12-1.8 W/m2 K) at 100 W for 2-4 mm fin spacing due to choked fin array end condition. The end flow is not sufficient to reach up to central portion of fin array and in the middle portion there is an unsteady down and up flow pattern resulting in sliding chimney. The central bottom portion of fin array channel does not contribute much in heat dissipation for S = 2-4 mm. The ha has significantly improved at higher spacing as compared to lower spacing region. The single chimney flow pattern is preferred from heat transfer point of view. The optimum spacing is confirmed in the range of 8-10 mm. The average heat transfer results are compared with previous literature and showed similar trend and satisfactory agreement. An empirical equation has been proposed to correlate the average Nusselt number as a function of Grashof number and fin spacing to height ratio. The average error for this equation is -0.32 %.
Methodology for Flight Relevant Arc-Jet Testing of Flexible Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Mazaheri, Alireza; Bruce, Walter E., III; Mesick, Nathaniel J.; Sutton, Kenneth

2013-01-01

A methodology to correlate flight aeroheating environments to the arc-jet environment is presented. For a desired hot-wall flight heating rate, the methodology provides the arcjet bulk enthalpy for the corresponding cold-wall heating rate. A series of analyses were conducted to examine the effects of the test sample model holder geometry to the overall performance of the test sample. The analyses were compared with arc-jet test samples and challenges and issues are presented. The transient flight environment was calculated for the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Earth Atmospheric Reentry Test (HEART) vehicle, which is a planned demonstration vehicle using a large inflatable, flexible thermal protection system to reenter the Earth's atmosphere from the International Space Station. A series of correlations were developed to define the relevant arc-jet test environment to properly approximate the HEART flight environment. The computed arcjet environments were compared with the measured arc-jet values to define the uncertainty of the correlated environment. The results show that for a given flight surface heat flux and a fully-catalytic TPS, the flight relevant arc-jet heat flux increases with the arc-jet bulk enthalpy while for a non-catalytic TPS the arc-jet heat flux decreases with the bulk enthalpy.
Heat Loss May Explain Bill Size Differences between Birds Occupying Different Habitats

PubMed Central

Greenberg, Russell; Cadena, Viviana; Danner, Raymond M.; Tattersall, Glenn

2012-01-01

Background Research on variation in bill morphology has focused on the role of diet. Bills have other functions, however, including a role in heat and water balance. The role of the bill in heat loss may be particularly important in birds where water is limiting. Song sparrows localized in coastal dunes and salt marsh edge (Melospiza melodia atlantica) are similar in size to, but have bills with a 17% greater surface area than, those that live in mesic habitats (M. m. melodia), a pattern shared with other coastal sparrows. We tested the hypotheses that sparrows can use their bills to dissipate “dry” heat, and that heat loss from the bill is higher in M. m. atlantica than M. m. melodia, which would indicate a role of heat loss and water conservation in selection for bill size. Methodology/Principal Findings Bill, tarsus, and body surface temperatures were measured using thermal imaging of sparrows exposed to temperatures from 15–37°C and combined with surface area and physical modeling to estimate the contribution of each body part to total heat loss. Song sparrow bills averaged 5–10°C hotter than ambient. The bill of M. m atlantica dissipated up to 33% more heat and 38% greater proportion of total heat than that of M. m. melodia. This could potentially reduce water loss requirements by approximately 7.7%. Conclusions/Significance This >30% higher heat loss in the bill of M. m. atlantica is independent of evaporative water loss and thus could play an important role in the water balance of sparrows occupying the hot and exposed dune/salt marsh environments during the summer. Heat loss capacity and water conservation could play an important role in the selection for bill size differences between bird populations and should be considered along with trophic adaptations when studying variation in bill size. PMID:22848413

The embodiment design of the heat rejection system for the portable life support system

NASA Technical Reports Server (NTRS)

Stuckwisch, Sue; Francois, Jason; Laughlin, Julia; Phillips, Lee; Carrion, Carlos A.

1994-01-01

The Portable Life Support System (PLSS) provides a suitable environment for the astronaut in the Extravehicular Mobility Unit (EMU), and the heat rejection system controls the thermal conditions in the space suit. The current PLSS sublimates water to the space environment; therefore, the system loses mass. Since additional supplies of fluid must be available on the Space Shuttle, NASA desires a closed heat rejecting system. This document presents the embodiment design for a radiative plate heat rejection system without mass transfer to the space environment. This project will transform the concept variant into a design complete with material selection, dimensions of the system, layouts of the heat rejection system, suggestions for manufacturing, and financial viability.
Roughness induced transition and heat transfer augmentation in hypersonic environments

NASA Astrophysics Data System (ADS)

Wassel, A. T.; Shih, W. C. L.; Courtney, J. F.

Boundary layer transition and surface heating distributions on graphite, fine weave carbon-carbon, and metallic nosetip materials were derived from surface temperature responses measured in nitrogen environments during both free-flight and track-guided testing in hypersonic environments. Innovative test procedures were developed, and heat transfer results were validated against established theory through experiments using a super-smooth tungsten model. Quantitative definitions of mean transition front locations were established by deriving heat flux distributions from measured temperatures, and comparisons made with existing nosetip transition correlations. Qualitative transition locations were inferred directly from temperature distributions to investigate preferred orientations on fine weave nosetips. Levels of roughness augmented heat transfer were generally shown to be below values predicted by state-of-the-art methods.
Striation pattern of target particle and heat fluxes in three dimensional simulations for DIII-D [On the striation pattern of target particle and heat fluxes in three dimensional simulations for DIII-D

DOE PAGES

Frerichs, H.; Schmitz, Oliver; Reiter, D.; ...

2014-02-04

The application of resonant magnetic perturbations (RMPs) results in a non-axisymmetric striation pattern of magnetic field lines from the plasma interior which intersect the divertor targets. The impact on related particle and heat fluxes is investigated by three dimensional computer simulations for two different recycling conditions (controlled via neutral gas pumping). It is demonstrated that a mismatch between the particle and heat flux striation pattern, as is repeatedly observed in ITER similar shape H-mode plasmas at DIII-D, can be reproduced by the simulations for high recycling conditions at the onset of partial detachment. Finally, these results indicate that a detailedmore » knowledge of the particle and energy balance is at least as important for realistic simulations as the consideration of a change in the magnetic field structure by plasma response effects.« less
City 2020+

NASA Astrophysics Data System (ADS)

Schneider, C.; Buttstädt, M.; Merbitz, H.; Sachsen, T.; Ketzler, G.; Michael, S.; Klemme, M.; Dott, W.; Selle, K.; Hofmeister, H.

2010-09-01

This research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the City of Aachen as a case study. CITY 2020+ develops scenarios, options and tools for planning and developing sustainable future city structures. We investigate how urban environment, political structure and residential behavior can best be adapted, with attention to the interactions among structural, political, and sociological configurations and with their consequences on human health. Demographers project that in the EU-25-States by 2050, approximately 30% of the population will be over age 65. Also by 2050, average tem¬peratures are projected to rise by 1 to 2 K. Combined, Europe can expect enhanced thermal stress and higher levels of particulate matter. CITY 2020+ amongst other sub-projects includes research project dealing with (1) a micro-scale assessment of blockages to low-level cold-air drainage flow into the city centre by vegetation and building structures, (2) a detailed analysis of the change of probability density functions related to the occurrence of heat waves during summer and the spatial and temporal structure of the urban heat island (UHI) (3) a meso-scale analysis of particulate matter (PM) concentrations depending on topography, local meteorological conditions and synoptic-scale weather patterns. First results will be presented specifically from sub-projects related to vegetation barriers within cold air drainage, the assessment of the UHI and the temporal and spatial pattern of PM loadings in the city centre. The analysis of the cold air drainage flow is investigated in two consecutive years with a clearing of vegetation stands in the beginning of the second year early in 2010. The spatial pattern of the UHI and its possible enhancement by climate change is addressed employing a unique setup using GPS devices and temperature probes fixed to several public transport units running all across the city. This is accompanied by an analysis of probability density functions (PDF) for heat waves based on recent climate data and climate projections. A dense net of 40 PM measurement sites is operated in order to obtain the spatial pattern of PM concentration as depending on meteorological condition and location. It is lined out how this climate related sub-projects interact with investigations on social networks, governance issues, buildings structure development and health outcome. Related to the later the chemical composition of PM is analyzed in more detail and related to the spatial patterns of health deficiencies. At a later stage City2020+ will propose new strategies based on cooperation from the fields of medicine, geography, sociology, history, civil engineering, and architecture for adapting the city for future needs. The Project CITY 2020+ is part of the interdisciplinary Project House HumTec (Human Sciences and Technology) at RWTH Aachen University funded by the Excellence Initiative of the German federal and state governments through the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG).
Method of lift-off patterning thin films in situ employing phase change resists

DOEpatents

Bahlke, Matthias Erhard; Baldo, Marc A; Mendoza, Hiroshi Antonio

2014-09-23

Method for making a patterned thin film of an organic semiconductor. The method includes condensing a resist gas into a solid film onto a substrate cooled to a temperature below the condensation point of the resist gas. The condensed solid film is heated selectively with a patterned stamp to cause local direct sublimation from solid to vapor of selected portions of the solid film thereby creating a patterned resist film. An organic semiconductor film is coated on the patterned resist film and the patterned resist film is heated to cause it to sublime away and to lift off because of the phase change.
Human thermal physiological and psychological responses under different heating environments.

PubMed

Wang, Zhaojun; Ning, Haoran; Ji, Yuchen; Hou, Juan; He, Yanan

2015-08-01

Anecdotal evidence suggests that many residents of severely cold areas of China who use floor heating (FH) systems feel warmer but drier compared to those using radiant heating (RH) systems. However, this phenomenon has not been verified experimentally. In order to validate the empirical hypothesis, and research the differences of human physiological and psychological responses in these two asymmetrical heating environments, an experiment was designed to mimic FH and RH systems. The subjects participating in the experiment were volunteer college-students. During the experiment, the indoor air temperature, air speed, relative humidity, globe temperature, and inner surface temperatures were measured, and subjects' heart rate, blood pressure and skin temperatures were recorded. The subjects were required to fill in questionnaires about their thermal responses during testing. The results showed that the subjects' skin temperatures, heart rate and blood pressure were significantly affected by the type of heating environment. Ankle temperature had greatest impact on overall thermal comfort relative to other body parts, and a slightly cool FH condition was the most pleasurable environment for sedentary subjects. The overall thermal sensation, comfort and acceptability of FH were higher than that of RH. However, the subjects of FH felt drier than that of RH, although the relative humidity in FH environments was higher than that of the RH environment. In future environmental design, the thermal comfort of the ankles should be scrutinized, and a FH cool condition is recommended as the most comfortable thermal environment for office workers. Consequently, large amounts of heating energy could be saved in this area in the winter. The results of this study may lead to more efficient energy use for office or home heating systems. Copyright © 2015 Elsevier Ltd. All rights reserved.
Effect of HF Heating Array Directivity Pattern on the Frequency Response of Generated ELF/VLF.

DTIC Science & Technology

1983-01-01

radiators ....... ............ 4 1-2 HF heating array ........ ................... 9 1-3 HF heating array element ...... ................ 9 1-4 View of top...elements looking down at pyramid ....... 9 1-5 Non-planar log-periodic antenna semi-structure dimensions ............ . ....... 10 l-6a Power gain vs...22 1-8 Orientation of 4- and 8-element arrays .. ......... .. 24 1- 9 Comparison of experimental and theoretical patterns. . . 27 1-10 Directive
Line patterning of anisotropic spin chains by polarized laser for application in micro-thermal management

NASA Astrophysics Data System (ADS)

Terakado, Nobuaki; Takahashi, Ryosuke; Takahashi, Yoshihiro; Fujiwara, Takumi

2017-05-01

The control of heat flow has become increasingly important in energy saving and harvesting. Among various thermal management materials, spinon thermal conductivity materials are promising for heat flow control at microscales because they exhibit high, anisotropic thermal conductivity resulting from spin chains. However, there has been only little development of the materials for controlling heat flow. Here, we present the line patterning of the spin chain structure on a SrCuO2 nanocrystalline film by laser scanning. When the polarization direction of laser light was orthogonal to the scanning direction, we found that the spin-chain structure anisotropically grew on the patterned line.
Optimal joule heating of the subsurface

DOEpatents

Berryman, J.G.; Daily, W.D.

1994-07-05

A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.
PALM-USM v1.0: A new urban surface model integrated into the PALM large-eddy simulation model

NASA Astrophysics Data System (ADS)

Resler, Jaroslav; Krč, Pavel; Belda, Michal; Juruš, Pavel; Benešová, Nina; Lopata, Jan; Vlček, Ondřej; Damašková, Daša; Eben, Kryštof; Derbek, Přemysl; Maronga, Björn; Kanani-Sühring, Farah

2017-10-01

Urban areas are an important part of the climate system and many aspects of urban climate have direct effects on human health and living conditions. This implies that reliable tools for local urban climate studies supporting sustainable urban planning are needed. However, a realistic implementation of urban canopy processes still poses a serious challenge for weather and climate modelling for the current generation of numerical models. To address this demand, a new urban surface model (USM), describing the surface energy processes for urban environments, was developed and integrated as a module into the PALM large-eddy simulation model. The development of the presented first version of the USM originated from modelling the urban heat island during summer heat wave episodes and thus implements primarily processes important in such conditions. The USM contains a multi-reflection radiation model for shortwave and longwave radiation with an integrated model of absorption of radiation by resolved plant canopy (i.e. trees, shrubs). Furthermore, it consists of an energy balance solver for horizontal and vertical impervious surfaces, and thermal diffusion in ground, wall, and roof materials, and it includes a simple model for the consideration of anthropogenic heat sources. The USM was parallelized using the standard Message Passing Interface and performance testing demonstrates that the computational costs of the USM are reasonable on typical clusters for the tested configurations. The module was fully integrated into PALM and is available via its online repository under the GNU General Public License (GPL). The USM was tested on a summer heat-wave episode for a selected Prague crossroads. The general representation of the urban boundary layer and patterns of surface temperatures of various surface types (walls, pavement) are in good agreement with in situ observations made in Prague. Additional simulations were performed in order to assess the sensitivity of the results to uncertainties in the material parameters, the domain size, and the general effect of the USM itself. The first version of the USM is limited to the processes most relevant to the study of summer heat waves and serves as a basis for ongoing development which will address additional processes of the urban environment and lead to improvements to extend the utilization of the USM to other environments and conditions.
Hierarchical and Complex System Entropy Clustering Analysis Based Validation for Traditional Chinese Medicine Syndrome Patterns of Chronic Atrophic Gastritis.

PubMed

Zhang, Yin; Liu, Yue; Li, Yannan; Zhao, Xia; Zhuo, Lin; Zhou, Ajian; Zhang, Li; Su, Zeqi; Chen, Cen; Du, Shiyu; Liu, Daming; Ding, Xia

2018-03-22

Chronic atrophic gastritis (CAG) is the precancerous stage of gastric carcinoma. Traditional Chinese Medicine (TCM) has been widely used in treating CAG. This study aimed to reveal core pathogenesis of CAG by validating the TCM syndrome patterns and provide evidence for optimization of treatment strategies. This is a cross-sectional study conducted in 4 hospitals in China. Hierarchical clustering analysis (HCA) and complex system entropy clustering analysis (CSECA) were performed, respectively, to achieve syndrome pattern validation. Based on HCA, 15 common factors were assigned to 6 syndrome patterns: liver depression and spleen deficiency and blood stasis in the stomach collateral, internal harassment of phlegm-heat and blood stasis in the stomach collateral, phlegm-turbidity internal obstruction, spleen yang deficiency, internal harassment of phlegm-heat and spleen deficiency, and spleen qi deficiency. By CSECA, 22 common factors were assigned to 7 syndrome patterns: qi deficiency, qi stagnation, blood stasis, phlegm turbidity, heat, yang deficiency, and yin deficiency. Combination of qi deficiency, qi stagnation, blood stasis, phlegm turbidity, heat, yang deficiency, and yin deficiency may play a crucial role in CAG pathogenesis. In accord with this, treatment strategies by TCM herbal prescriptions should be targeted to regulating qi, activating blood, resolving turbidity, clearing heat, removing toxin, nourishing yin, and warming yang. Further explorations are needed to verify and expand the current conclusions.
Low gravity transfer line chilldown

NASA Technical Reports Server (NTRS)

Antar, Basil N.; Collins, Frank G.; Kawaji, Masahiro

1992-01-01

The progress to date is presented in providing predictive capabilities for the transfer line chilldown problem in low gravity environment. A low gravity experimental set up was designed and flown onboard the NASA/KC-135 airplane. Some results of this experimental effort are presented. The cooling liquid for these experiments was liquid nitrogen. The boiling phenomenon was investigated in this case using flow visualization techniques as well as recording wall temperatures. The flow field was established by injecting cold liquid in a heated tube whose temperature was set above saturation values. The tubes were vertically supported with the liquid injected from the lower end of the tube. The results indicate substantial differences in the flow patterns established during boiling between the ground based, (1-g), experiments and the flight experiments, (low-g). These differences in the flow patterns will be discussed and some explanations will be offered.
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.
Tree-crown-resolving large-eddy simulation for evaluating greenery effects on urban heat environments

NASA Astrophysics Data System (ADS)

Matsuda, K.; Onishi, R.; Takahashi, K.

2017-12-01

Urban high temperatures due to the combined influence of global warming and urban heat islands increase the risk of heat stroke. Greenery is one of possible countermeasures for mitigating the heat environments since the transpiration and shading effect of trees can reduce the air temperature and the radiative heat flux. In order to formulate effective measures, it is important to estimate the influence of the greenery on the heat stroke risk. In this study, we have developed a tree-crown-resolving large-eddy simulation (LES) model that is coupled with three-dimensional radiative transfer (3DRT) model. The Multi-Scale Simulator for the Geoenvironment (MSSG) is used for performing building- and tree-crown-resolving LES. The 3DRT model is implemented in the MSSG so that the 3DRT is calculated repeatedly during the time integration of the LES. We have confirmed that the computational time for the 3DRT model is negligibly small compared with that for the LES and the accuracy of the 3DRT model is sufficiently high to evaluate the radiative heat flux at the pedestrian level. The present model is applied to the analysis of the heat environment in an actual urban area around the Tokyo Bay area, covering 8 km × 8 km with 5-m grid mesh, in order to confirm its feasibility. The results show that the wet-bulb globe temperature (WBGT), which is an indicator of the heat stroke risk, is predicted in a sufficiently high accuracy to evaluate the influence of tree crowns on the heat environment. In addition, by comparing with a case without the greenery in the Tokyo Bay area, we have confirmed that the greenery increases the low WBGT areas in major pedestrian spaces by a factor of 3.4. This indicates that the present model can predict the greenery effect on the urban heat environment quantitatively.
Temperature distribution and heat radiation of patterned surfaces at short wavelengths.

PubMed

Emig, Thorsten

2017-05-01

We analyze the equilibrium spatial distribution of surface temperatures of patterned surfaces. The surface is exposed to a constant external heat flux and has a fixed internal temperature that is coupled to the outside heat fluxes by finite heat conductivity across the surface. It is assumed that the temperatures are sufficiently high so that the thermal wavelength (a few microns at room temperature) is short compared to all geometric length scales of the surface patterns. Hence the radiosity method can be employed. A recursive multiple scattering method is developed that enables rapid convergence to equilibrium temperatures. While the temperature distributions show distinct dependence on the detailed surface shapes (cuboids and cylinder are studied), we demonstrate robust universal relations between the mean and the standard deviation of the temperature distributions and quantities that characterize overall geometric features of the surface shape.
Temperature distribution and heat radiation of patterned surfaces at short wavelengths

NASA Astrophysics Data System (ADS)

Emig, Thorsten

2017-05-01

We analyze the equilibrium spatial distribution of surface temperatures of patterned surfaces. The surface is exposed to a constant external heat flux and has a fixed internal temperature that is coupled to the outside heat fluxes by finite heat conductivity across the surface. It is assumed that the temperatures are sufficiently high so that the thermal wavelength (a few microns at room temperature) is short compared to all geometric length scales of the surface patterns. Hence the radiosity method can be employed. A recursive multiple scattering method is developed that enables rapid convergence to equilibrium temperatures. While the temperature distributions show distinct dependence on the detailed surface shapes (cuboids and cylinder are studied), we demonstrate robust universal relations between the mean and the standard deviation of the temperature distributions and quantities that characterize overall geometric features of the surface shape.
"Twisted Beam" SEE Observations of Ionospheric Heating from HAARP

NASA Astrophysics Data System (ADS)

Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.; Han, S.-M.; Pedersen, T. R.; Scales, W. A.

2015-10-01

Nonlinear interactions of high power HF radio waves in the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska is the world's largest heating facility, yielding effective radiated powers in the gigawatt range. New results are present from HAARP experiments using a "twisted beam" excitation mode. Analysis of twisted beam heating shows that the SEE results obtained are identical to more traditional patterns. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional "solid spot" region from a pencil beam. The ring heating pattern may be more conducive to the creation of stable artificial airglow layers because of the horizontal structure of the ring. The results of these runs include artificial layer creation and evolution as pertaining to the twisted beam pattern. The SEE measurements aid the interpretation of the twisted beam interactions in the ionosphere.
Experiment of flow regime map and local condensing heat transfer coefficients inside three dimensional inner microfin tubes

NASA Astrophysics Data System (ADS)

Du, Yang; Xin, Ming Dao

1999-03-01

This paper developed a new type of three dimensional inner microfin tube. The experimental results of the flow patterns for the horizontal condensation inside these tubes are reported in the paper. The flow patterns for the horizontal condensation inside the new made tubes are divided into annular flow, stratified flow and intermittent flow within the test conditions. The experiments of the local heat transfer coefficients for the different flow patterns have been systematically carried out. The experiments of the local heat transfer coefficients changing with the vapor dryness fraction have also been carried out. As compared with the heat transfer coefficients of the two dimensional inner microfin tubes, those of the three dimensional inner microfin tubes increase 47-127% for the annular flow region, 38-183% for the stratified flow and 15-75% for the intermittent flow, respectively. The enhancement factor of the local heat transfer coefficients is from 1.8-6.9 for the vapor dryness fraction from 0.05 to 1.
Calculation of Shuttle Base Heating Environments and Comparison with Flight Data

NASA Technical Reports Server (NTRS)

Greenwood, T. F.; Lee, Y. C.; Bender, R. L.; Carter, R. E.

1983-01-01

The techniques, analytical tools, and experimental programs used initially to generate and later to improve and validate the Shuttle base heating design environments are discussed. In general, the measured base heating environments for STS-1 through STS-5 were in good agreement with the preflight predictions. However, some changes were made in the methodology after reviewing the flight data. The flight data is described, preflight predictions are compared with the flight data, and improvements in the prediction methodology based on the data are discussed.
Candidate Earth Entry Trajectories to Mimic Venus Aerocapture Using a Lifting ADEPT

NASA Technical Reports Server (NTRS)

Williams, Jimmy

2017-01-01

A Lifting ADEPT is considered for aerocapture at Venus. Analysis concerning the heating environment leads to an initial sizing estimate. In tandem, a direct entry profile at Earth is considered to act as a facsimile for the Venus aerocapture heating environment. The bounds of this direct entry profile are determined and it is found that a trajectory from a Geostationary Transfer Orbit with a Lifting ADEPT capable of fitting on a rideshare opportunity is capable of matching certain aspects of this heating environment.

Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology

PubMed Central

Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting. PMID:29551957
Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology.

PubMed

Chen, Fengchen; Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting.
Exploratory Environmental Tests of Several Heat Shields

NASA Technical Reports Server (NTRS)

Goodman, George P.; Betts, John, Jr.

1961-01-01

Exploratory tests have been conducted with several conceptual radiative heat shields of composite construction. Measured transient temperature distributions were obtained for a graphite heat shield without insulation and with three types of insulating materials, and for a metal multipost heat shield, at surface temperatures of approximately 2,000 F and 1,450 F, respectively, by use of a radiant-heat facility. The graphite configurations suffered loss of surface material under repeated irradiation. Temperature distribution calculated for the metal heat shield by a numerical procedure was in good agreement with measured data. Environmental survival tests of the graphite heat shield without insulation, an insulated multipost heat shield, and a stainless-steel-tile heat shield were made at temperatures of 2,000 F and dynamic pressures of approximately 6,000 lb/sq ft, provided by an ethylene-heated jet operating at a Mach number of 2.0 and sea-level conditions. The graphite heat shield survived the simulated aerodynamic heating and pressure loading. A problem area exists in the design and materials for heat-resistant fasteners between the graphite shield and the base structure. The insulated multipost heat shield was found to be superior to the stainless-steel-tile heat shield in retarding heat flow. Over-lapped face-plate joints and surface smoothness of the insulated multi- post heat shield were not adversely affected by the test environment. The graphite heat shield without insulation survived tests made in the acoustic environment of a large air jet. This acoustic environment is random in frequency and has an overall noise level of 160 decibels.
Social vulnerability to heat in Greater Atlanta, USA: spatial pattern of heat, NDVI, socioeconomics and household composition

NASA Astrophysics Data System (ADS)

Sim, Sunhui

2017-10-01

The purpose of the article is evaluating spatial patterns of social vulnerability to heat in Greater Atlanta in 2015. The social vulnerability to heat is an index of socioeconomic status, household composition, land surface temperature and normalized differential vegetation index (NDVI). Land surface temperature and NDVI were derived from the red, NIR and thermal infrared (TIR) of a Landsat OLI/TIRS images collected on September 14, 2015. The research focus is on the variation of heat vulnerability in Greater Atlanta. The study found that heat vulnerability is highly clustered spatially, resulting in "hot spots" and "cool spots". The results show significant health disparities. The hotspots of social vulnerability to heat occurred in neighborhoods with lower socioeconomic status as measured by low education, low income and more poverty, greater proportion of elderly people and young children. The findings of this study are important for identifying clusters of heat vulnerability and the relationships with social factors. These significant results provide a basis for heat intervention services.
Two-phase gas-liquid flow characteristics inside a plate heat exchanger

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

Nilpueng, Kitti; Wongwises, Somchai

In the present study, the air-water two-phase flow characteristics including flow pattern and pressure drop inside a plate heat exchanger are experimentally investigated. A plate heat exchanger with single pass under the condition of counter flow is operated for the experiment. Three stainless steel commercial plates with a corrugated sinusoidal shape of unsymmetrical chevron angles of 55 and 10 are utilized for the pressure drop measurement. A transparent plate having the same configuration as the stainless steel plates is cast and used as a cover plate in order to observe the flow pattern inside the plate heat exchanger. The air-watermore » mixture flow which is used as a cold stream is tested in vertical downward and upward flow. The results from the present experiment show that the annular-liquid bridge flow pattern appeared in both upward and downward flows. However, the bubbly flow pattern and the slug flow pattern are only found in upward flow and downward flow, respectively. The variation of the water and air velocity has a significant effect on the two-phase pressure drop. Based on the present data, a two-phase multiplier correlation is proposed for practical application. (author)« less
Thin film heat flux sensor for Space Shuttle Main Engine turbine environment

NASA Technical Reports Server (NTRS)

Will, Herbert

1991-01-01

The Space Shuttle Main Engine (SSME) turbine environment stresses engine components to their design limits and beyond. The extremely high temperatures and rapid temperature cycling can easily cause parts to fail if they are not properly designed. Thin film heat flux sensors can provide heat loading information with almost no disturbance of gas flows or of the blade. These sensors can provide steady state and transient heat flux information. A thin film heat flux sensor is described which makes it easier to measure small temperature differences across very thin insulating layers.
Future crop production threatened by extreme heat

NASA Astrophysics Data System (ADS)

Siebert, Stefan; Ewert, Frank

2014-04-01

Heat is considered to be a major stress limiting crop growth and yields. While important findings on the impact of heat on crop yield have been made based on experiments in controlled environments, little is known about the effects under field conditions at larger scales. The study of Deryng et al (2014 Global crop yield response to extreme heat stress under multiple climate change futures Environ. Res. Lett. 9 034011), analysing the impact of heat stress on maize, spring wheat and soya bean under climate change, represents an important contribution to this emerging research field. Uncertainties in the occurrence of heat stress under field conditions, plant responses to heat and appropriate adaptation measures still need further investigation.
Urbanization Level and Vulnerability to Heat-Related Mortality in Jiangsu Province, China

PubMed Central

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Ma, Zongwei; Liu, Yang; Huang, Lei; Bi, Jun; Kinney, Patrick L.

2016-01-01

Background: Although adverse effects of high temperature on mortality have been studied extensively in urban areas, little is known of the heat–mortality associations outside of cities. Objective: We investigated whether heat–mortality associations differed between urban and nonurban areas and how urbanicity affected the vulnerability to heat-related mortality. Methods: We first analyzed heat-related mortality risk in each of 102 counties in Jiangsu Province, China, during 2009–2013 using a distributed-lag nonlinear model. The county-specific estimates were then pooled for more urban (percentage of urban population ≥ 57.11%) and less urban (percentage of urban population < 57.11%) counties using a Bayesian hierarchical model. To explain the spatial variation in associations by county, county-level characteristics affecting heat vulnerability were also examined. Results: We found that the overall mortality risk comparing the 99th vs. 75th percentiles of temperature was 1.43 [95% posterior intervals (PI): 1.36, 1.50] in less urban counties and 1.26 (95% PI: 1.23, 1.30) in more urban counties. The heat effects on cardiorespiratory mortality followed a similar pattern. Higher education level and prevalence of air conditioning were significantly associated with counties having lower risks, whereas percentage of elderly people was significantly associated with increased risks. Conclusion: Our findings reveal that nonurban areas have significant heat-related mortality risks in Jiangsu, China. These results suggest the need for enhanced adaptation planning in Chinese nonurban areas under a changing climate. Citation: Chen K, Zhou L, Chen X, Ma Z, Liu Y, Huang L, Bi J, Kinney PL. 2016. Urbanization level and vulnerability to heat-related mortality in Jiangsu Province, China. Environ Health Perspect 124:1863–1869; http://dx.doi.org/10.1289/EHP204 PMID:27152420
Visualisation of flow patterns in straight and C-shape thermosyphons

NASA Astrophysics Data System (ADS)

Ong, K. S.; Tshai, K. H.; Firwana, A.

2017-04-01

A heat pipe is a passive heat transfer device capable of transferring a large quantity of heat effectively and efficiently over a long distance and with a small temperature difference between the heat source and heat sink. A heat pipe consists of a metal pipe initially vacuumed and then filled with a small quantity of fluid inside. The pipe is separated into a heating (evaporator) section and a cooling (condenser) section by an adiabatic section. In a run-around-coil heating, ventilation and air conditioning system, a wrap-around heat pipe heat exchanger could be employed to increase dehumidification and to reduce cooling costs. The thermal performance of a thermosyphon is dependent upon type of fill liquid, fill ratio, power input, pipe inclination and pipe dimensions. The boiling and condensation processes that occur inside a thermosyphon are quite complex. During operation, dry-out, burn-out or boiling limit, entrainment or flooding limit and geysering occur. These phenomena would lead to non-uniform axial wall temperature distribution in the pipe, or worse still, ineffective operation. In order to have a better understanding of the internal heat transfer phenomena, a visual study using transparent glass tubes and high speed camera recording of the internal flow patterns would be most helpful. This paper reports on an experimental investigation conducted to visualise the flow patterns in straight and C-shape thermosyphons. The pictures recorded enabled the internal flow boiling and condensation pattern occurring inside a straight and a C-shape thermosyphon to be observed. The thermosyphons were fabricated from 10 mm O/D × 8 mm I/D × 300 mm long glass tubes and filled with water with fill ratios from 0.5 - 1.5. The evaporator sections of the thermosyphons were immersed into a hot water tank that was electrically heated from cold at ambient temperature till boiling. Cooling of the condenser section was achieved using a fan. Preliminary results showed that dry-out occurred earlier at lower evaporator temperatures with small fill ratios. Further investigations to determine saturation and thermosyphon wall temperatures with various fill liquids and at different fill ratios, inclinations and pipe sizes are necessary with a more sophisticated video recording system.
Heat shock proteins in relation to heat stress tolerance of creeping bentgrass at different N levels.

PubMed

Wang, Kehua; Zhang, Xunzhong; Goatley, Mike; Ervin, Erik

2014-01-01

Heat stress is a primary factor causing summer bentgrass decline. Changes in gene expression at the transcriptional and/or translational level are thought to be a fundamental mechanism in plant response to environmental stresses. Heat stress redirects protein synthesis in higher plants and results in stress protein synthesis, particularly heat shock proteins (HSPs). The goal of this work was to analyze the expression pattern of major HSPs in creeping bentgrass (Agrostis stolonifera L.) during different heat stress periods and to study the influence of nitrogen (N) on the HSP expression patterns. A growth chamber study on 'Penn-A4' creeping bentgrass subjected to 38/28°C day/night for 50 days, was conducted with four nitrate rates (no N-0, low N-2.5, medium N-7.5, and high N-12.5 kg N ha-1) applied biweekly. Visual turfgrass quality (TQ), normalized difference vegetation index (NDVI), photochemical efficiency of photosystem II (Fv/Fm), shoot electrolyte leakage (ShEL), and root viability (RV) were monitored, along with the expression pattern of HSPs. There was no difference in measured parameters between treatments until week seven, except TQ at week five. At week seven, grass at medium N had better TQ, NDVI, and Fv/Fm accompanied by lower ShEL and higher RV, suggesting a major role in improved heat tolerance. All the investigated HSPs (HSP101, HSP90, HSP70, and sHSPs) were up-regulated by heat stress. Their expression patterns indicated cooperation between different HSPs and their roles in bentgrass thermotolerance. In addition, their production seems to be resource dependent. This study could further improve our understanding about how different N levels affect bentgrass thermotolerance.
Heat exposure in cities: combining the dynamics of temperature and population

NASA Astrophysics Data System (ADS)

Hu, L.; Wilhelmi, O.; Uejio, C. K.

2017-12-01

Assessment of human exposure to extreme heat requires the distributions of temperature and population. However, both variables are dynamic, thus presenting many challenges in capturing temperature and population patterns spatially and over time in an urban context. This study aims to improve the understanding of spatiotemporal patterns of urban population exposure to heat, taking Chicago, USA as an example. We estimate the hourly, geographically variable, population distribution considering commute of workers and students in a regular weekday and analyze the diurnal air temperature patterns during different meteorological conditions from satellite observations. The results show a relatively larger temperature increase in less urbanized areas during extreme heat events (EHEs), resulting in a spatially homogeneous temperature distribution over Chicago Metropolitan area. A lake cooling effect is weaker during EHEs. Population dynamics due to daily commute determine higher population density in more urbanized areas during daytime. The city-wide analysis reveals that the exposure is more sensitive to the nighttime temperature increases, and EHEs enhance this sensitivity. The high exposure hotspots are identified at the northwest Chicago, Cicero and Oak Park areas, where the influence from Lake Michigan is weakened, while the spatial extent of high outdoor exposure areas varies diurnally. This study's findings have potential to better inform general heat mitigation strategies during hot summer months and facilitate emergency response during EHEs. Availability of remotely-sensed temperature observations as well as the workers and students commute-adjusted population data allows for the adoption of this study's methodology in other major metropolitan areas. A better understanding of space-time patterns of urban population's exposure to heat will further enable local decision makers to mitigate extreme heat health risks and develop more targeted heat preparedness and response strategies.
Experiment and modeling: Ignition of aluminum particles with a carbon dioxide laser

NASA Astrophysics Data System (ADS)

Mohan, Salil

Aluminum is a promising ingredient for high energy density compositions used in propulsion systems, explosives, and pyrotechnics. Aluminum powder fuel additives enable one to achieve higher combustion enthalpies and reaction temperatures. Therefore, to develop aluminum based novel and customized high density energetic materials, understanding of ignition and combustion kinetics of aluminum powders is required. In most practical systems, metal ignition and combustion occur in environments with rapidly changing temperatures and gas compositions. The kinetics of exothermic reactions in related energetic materials is commonly characterized by thermal analysis, where the heating rates are very low, on the order of 1--50 K/min. The extrapolation of the identified kinetics to the high heating rates is difficult and requires direct experimental verification. This difficulty led to development of new experimental approaches to directly characterize ignition kinetics for the heating rates in the range of 103--104 K/s. However, the practically interesting heating rates of 106 K/s range have not been achieved. This work is directed at development of an experimental technique and respective heat transfer model for studying ignition of aluminum and other micron-sized metallic particles at heating rates varied around 106 K/s. The experimental setup uses a focused CO2 laser as a heating source and a plate capacitor aerosolizer to feed the aluminum particles into the laser beam. The setup allows using different environment for particle aerosolization. The velocities of particles in the jet are in the range of 0.1 --0 3 m/s. For each selected jet velocity, the laser power is increased until the particles are observed to ignite. The ignition is detected optically using a digital camera and a photomultiplier. The ignition thresholds for spherical aluminum powder were measured at three different particle jet velocities, in air environment. A single particle heat transfer model was developed to describe the experiments. Experiments with different jet velocities in air environment were performed to validate the model. The interaction of the laser beam with particles is particle size dependent and a narrow range of particle sizes (around 3.4 microm) is heated most effectively. Therefore, the heat transfer model needs to be analyzed only for the particles with this specific size, which greatly simplifies the interpretation of experiments. Describing heating of a micron sized metal particle involves the transition regime heat transfer. A modified Fuchs model was used to describe the heat transfer in this study. In addition to dry air environment, the experimental technique was also used with other oxidizing environments, including O2, H2O, CO2 and mixtures thereof. It was observed that particle size capable of maintaining a vapor phase flame is a function of the environment. Arrhenius model kinetics parameters for Al ignition in O2, CO2 and H2O environments were determined.
Aerothermodynamic Environments Definition for the Mars Science Laboratory Entry Capsule

NASA Technical Reports Server (NTRS)

Edquist, Karl T.; Dyakonov, Artem A.; Wright, Michael J.; Tang, Chun Y.

2007-01-01

An overview of the aerothermodynamic environments definition status is presented for the Mars Science Laboratory entry vehicle. The environments are based on Navier-Stokes flowfield simulations on a candidate aeroshell geometry and worst-case entry heating trajectories. Uncertainties for the flowfield predictions are based primarily on available ground data since Mars flight data are scarce. The forebody aerothermodynamics analysis focuses on boundary layer transition and turbulent heating augmentation. Turbulent transition is expected prior to peak heating, a first for Mars entry, resulting in augmented heat flux and shear stress at the same heatshield location. Afterbody computations are also shown with and without interference effects of reaction control system thruster plumes. Including uncertainties, analysis predicts that the heatshield may experience peaks of 225 W/sq cm for turbulent heat flux, 0.32 atm for stagnation pressure, and 400 Pa for turbulent shear stress. The afterbody heat flux without thruster plume interference is predicted to be 7 W/sq cm on the backshell and 10 W/sq cm on the parachute cover. If the reaction control jets are fired near peak dynamic pressure, the heat flux at localized areas could reach as high as 76 W/sq cm on the backshell and 38 W/sq cm on the parachute cover, including uncertainties. The final flight environments used for hardware design will be updated for any changes in the aeroshell configuration, heating design trajectories, or uncertainties.
Mechanisms Involved in the Mitigation of Urban Heat Islands through Vegetation

NASA Astrophysics Data System (ADS)

Montalto, F. A.; Smalls-Mantey, L.

2016-12-01

Urban heat islands are one of many challenges presented by today's unprecedented patterns of urbanization. At higher densities, urban populations are more vulnerable to the increased temperatures that accompany urban landscape change. Though in the US it is funded principally as a means of stormwater management, urban green infrastructure (GI) actually alters hydrologic, energetic, and thermal budgets of urban environments, with a suite of potential co-benefits related to the health of people and ecosystems. Recent research has underscored the roles that vegetation plays in such processes, for example by facilitating evapotranspiration, and regulating air temperature and water availability. While the magnitude of these and other impacts is determined in part by the size, type, location, and configuration of GI facilities, few studies have attempted to characterize and to quantify how various vegetation-mediated processes in GI systems impact the energy and thermal properties of their surroundings. Using data collected at rooftop and ground level GI facilities including green roofs and bioretention areas monitored by Drexel University, this research illustrates the role that processes such as evapotranspiration play in the individual GI site cooling potential, reducing neighborhood vulnerability to the urban heat island effect.
Adapting wheat in Europe for climate change.

PubMed

Semenov, M A; Stratonovitch, P; Alghabari, F; Gooding, M J

2014-05-01

Increasing cereal yield is needed to meet the projected increased demand for world food supply of about 70% by 2050. Sirius, a process-based model for wheat, was used to estimate yield potential for wheat ideotypes optimized for future climatic projections for ten wheat growing areas of Europe. It was predicted that the detrimental effect of drought stress on yield would be decreased due to enhanced tailoring of phenology to future weather patterns, and due to genetic improvements in the response of photosynthesis and green leaf duration to water shortage. Yield advances could be made through extending maturation and thereby improve resource capture and partitioning. However the model predicted an increase in frequency of heat stress at meiosis and anthesis. Controlled environment experiments quantify the effects of heat and drought at booting and flowering on grain numbers and potential grain size. A current adaptation of wheat to areas of Europe with hotter and drier summers is a quicker maturation which helps to escape from excessive stress, but results in lower yields. To increase yield potential and to respond to climate change, increased tolerance to heat and drought stress should remain priorities for the genetic improvement of wheat.
Iterative motion compensation approach for ultrasonic thermal imaging

NASA Astrophysics Data System (ADS)

Fleming, Ioana; Hager, Gregory; Guo, Xiaoyu; Kang, Hyun Jae; Boctor, Emad

2015-03-01

As thermal imaging attempts to estimate very small tissue motion (on the order of tens of microns), it can be negatively influenced by signal decorrelation. Patient's breathing and cardiac cycle generate shifts in the RF signal patterns. Other sources of movement could be found outside the patient's body, like transducer slippage or small vibrations due to environment factors like electronic noise. Here, we build upon a robust displacement estimation method for ultrasound elastography and we investigate an iterative motion compensation algorithm, which can detect and remove non-heat induced tissue motion at every step of the ablation procedure. The validation experiments are performed on laboratory induced ablation lesions in ex-vivo tissue. The ultrasound probe is either held by the operator's hand or supported by a robotic arm. We demonstrate the ability to detect and remove non-heat induced tissue motion in both settings. We show that removing extraneous motion helps unmask the effects of heating. Our strain estimation curves closely mirror the temperature changes within the tissue. While previous results in the area of motion compensation were reported for experiments lasting less than 10 seconds, our algorithm was tested on experiments that lasted close to 20 minutes.
Studies on physiological responses of residents in Okinawa to a hot environment.

PubMed

Hori, S; Ihzuka, H; Nakamura, M

1976-01-01

In an attempt to reconfirm Kuno's observation that changes in sweating reaction during long-term heat acclimatization differ from those during short-term heat acclimatization, Ohara's sweating test was performed in summer in Okinawa on 37 male subjects, including 19 residents born and raised in Okinawa (group O) and 18 residents born and raised on one of the main Japanese islands (group M). Seasonal variation of adaptability to heat was also studied in some subjects of both groups. Group O showed significantly less sweat loss, lower Na concentration in sweat and a longer latent period for onset of sweating than group M. Group O showed no seasonal variation in sweat loss, while group M showed considerably greater sweat loss in summer than in winter. In both groups, lower Na concentration in sweat, lower rise in rectal temperature and lesser increase in heart rate in summer than in winter were observed. Seasonal difference in physiological responses of group O to heat exposure was less than that of group M. In conclusion, it was assumed that acclimatization to heat of group O had advanced further than that of group M and this was the reason for longer latent period of sweating and lesser sweat loss in group O in spite of the same rise in rectal temperature in both groups. Discussions were carried out to explain how the sweating pattern and mechanism of acclimatization in group O were different from those in group M.
Heat assisted magnetic recording with patterned FePt recording media using a lollipop near field transducer

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

Ghoreyshi, Ali; Victora, R. H., E-mail: victora@umn.edu

In heat-assisted magnetic recording, optical energy is transferred to a small optical spot on the recording media using a near field transducer. In this study, a scattered field finite difference time domain simulation is used to analyze the performance of a lollipop transducer in heat assisted magnetic recording on both a patterned FePt media and a continuous thin film. To represent wear, sharp corners of the peg are approximated with curved ones, which are found to narrow the track width without excessive loss of intensity. Compared with continuous media, the patterned media exhibits higher energy efficiency and a better concentratedmore » optical beam spot. This effect is due to the near field effects of patterned media on the performance of the transducer.« less
An Approach to In-Situ Observations of Volcanic Plumes

NASA Technical Reports Server (NTRS)

Smythe, W. D.; Lopes, M. C.; Pieri, D. C.; Hall, J. L.

2005-01-01

Volcanoes have long been recognized as playing a dominant role in the birth, and possibly the death, of biological populations. They are possible sources of primordial gases, provide conditions sufficient for creating amino acids, strongly affect the heat balance in the atmosphere, and have been shown to sustain life (in oceanic vents.) Eruptions can have profound effects on local flora and fauna, and for very large eruptions, may alter global weather patterns and cause entire species to fail. Measurements of particulates, gases, and dynamics within a volcanic plume are critical to understanding both how volcanoes work and how plumes affect populations, environment, and aviation. Volcanic plumes and associated eruption columns are a miasma of toxic gases, corrosive condensates, and abrasive particulates that makes them hazardous to nearby populations and poses a significant risk to all forms of aviation. Plumes also provide a mechanism for sampling the volcanic interior, which, for hydrothermal environments, may host unique biological populations.
Heat flux modeling using ion drift effects in DIII-D H-mode plasmas with resonant magnetic perturbations

DOE PAGES

Wingen, Andreas; Schmitz, Oliver; Evans, Todd E.; ...

2014-01-01

The heat flux patterns measured in low-collisionality DIII-D H-mode plasmas strongly deviate from simultaneously measured CII emission patterns, used as indicator of particle flux, during applied resonant magnetic perturbations. While the CII emission clearly shows typical striations, which are similar to magnetic footprint patterns obtained from vacuum field line tracing, the heat flux is usually dominated by one large peak at the strike point position. The vacuum approximation, which only considers applied magnetic fields and neglects plasma response and plasma effects, cannot explain the shape of the observed heat flux pattern. One possible explanation is the effect of particle drifts.more » This is included in the field line equations and the results are discussed with reference to the measurement. Electrons and ions show di fferent drift motions at thermal energy levels in a guiding center approximation. While electrons hardly deviate from the field lines, ions can drift several centimetres away from field line flux surfaces. A model is presented in which an ion heat flux, based on the ion drift motion from various kinetic energies as they contribute to a thermal Maxwellian distribution, is calculated. The simulated heat flux is directly compared to measurements with a varying edge safety factor q95. This analysis provides evidence for the dominate e ect of high-energy ions in carrying heat from the plasma inside the separatrix to the target. High-energy ions are deposited close to the unperturbed strike line while low-energy ions can travel into the striated magnetic topology.« less

Etiologies of the Relationships Among Body Mass Index and Cold-Heat Patterns: A Twin Study.

PubMed

Hur, Yoon-Mi; Jin, Hee-Jeong; Lee, Siwoo

2018-06-01

The phenotypic relationships between body mass index (BMI) and cold-heat patterns have been frequently reported, but the etiology of these relationships remains unknown. We previously demonstrated that the cold pattern (CP) and the heat pattern (HP) were heritable traits. In the present study, we explored underlying genetic and environmental structures of the relationships among BMI and the CP and the HP. Twins (N = 1,752) drawn from the South Korean twin registry completed a cold-heat pattern questionnaire via a telephone interview. The phenotypic correlations among the three phenotypes were moderate but significant. Cross-twin, cross-trait correlations among BMI and the CP and the HP were consistently greater in monozygotic than in dizygotic twins, suggesting the presence of genetic effects on the relationships between BMI and the two patterns. A trivariate Cholesky model was applied to the raw data. The results indicated that the phenotypic relationship between the HP and BMI was completely determined by common genetic influences, while the relationship between the CP and BMI was explained by both common genetic and common individual-specific environmental influences. The genetic correlation between the HP and the CP was not significant, suggesting that the two patterns may be genetically independent from each other. Genetic correlations were 0.31 between the HP and BMI, and -0.22 between the CP and BMI. The individual-specific environmental correlation was -0.22 between HP and CP, and between CP and BMI.
How the propagation of heat-flux modulations triggers E × B flow pattern formation.

PubMed

Kosuga, Y; Diamond, P H; Gürcan, O D

2013-03-08

We propose a novel mechanism to describe E×B flow pattern formation based upon the dynamics of propagation of heat-flux modulations. The E × B flows of interest are staircases, which are quasiregular patterns of strong, localized shear layers and profile corrugations interspersed between regions of avalanching. An analogy of staircase formation to jam formation in traffic flow is used to develop an extended model of heat avalanche dynamics. The extension includes a flux response time, during which the instantaneous heat flux relaxes to the mean heat flux, determined by symmetry constraints. The response time introduced here is the counterpart of the drivers' response time in traffic, during which drivers adjust their speed to match the background traffic flow. The finite response time causes the growth of mesoscale temperature perturbations, which evolve to form profile corrugations. The length scale associated with the maximum growth rate scales as Δ(2) ~ (v(thi)/λT(i))ρ(i)sqrt[χ(neo)τ], where λT(i) is a typical heat pulse speed, χ(neo) is the neoclassical thermal diffusivity, and τ is the response time of the heat flux. The connection between the scale length Δ(2) and the staircase interstep scale is discussed.
Heat Stress

MedlinePlus

... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir OSHA-NIOSH ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...
Historical GIS Data and Changes in Urban Morphological Parameters for the Analysis of Urban Heat Islands in Hong Kong

NASA Astrophysics Data System (ADS)

Peng, F.; Wong, M. S.; Nichol, J. E.; Chan, P. W.

2016-06-01

Rapid urban development between the 1960 and 2010 decades have changed the urban landscape and pattern in the Kowloon Peninsula of Hong Kong. This paper aims to study the changes of urban morphological parameters between the 1985 and 2010 and explore their influences on the urban heat island (UHI) effect. This study applied a mono-window algorithm to retrieve the land surface temperature (LST) using Landsat Thematic Mapper (TM) images from 1987 to 2009. In order to estimate the effects of local urban morphological parameters to LST, the global surface temperature anomaly was analysed. Historical 3D building model was developed based on aerial photogrammetry technique using aerial photographs from 1964 to 2010, in which the urban digital surface models (DSMs) including elevations of infrastructures and buildings have been generated. Then, urban morphological parameters (i.e. frontal area index (FAI), sky view factor (SVF)), vegetation fractional cover (VFC), global solar radiation (GSR), Normalized Difference Built-Up Index (NDBI), wind speed were derived. Finally, a linear regression method in Waikato Environment for Knowledge Analysis (WEKA) was used to build prediction model for revealing LST spatial patterns. Results show that the final apparent surface temperature have uncertainties less than 1 degree Celsius. The comparison between the simulated and actual spatial pattern of LST in 2009 showed that the correlation coefficient is 0.65, mean absolute error (MAE) is 1.24 degree Celsius, and root mean square error (RMSE) is 1.51 degree Celsius of 22,429 pixels.
Heat transfer evaluation in a plasma core reactor

NASA Technical Reports Server (NTRS)

Smith, D. E.; Smith, T. M.; Stoenescu, M. L.

1976-01-01

Numerical evaluations of heat transfer in a fissioning uranium plasma core reactor cavity, operating with seeded hydrogen propellant, was performed. A two-dimensional analysis is based on an assumed flow pattern and cavity wall heat exchange rate. Various iterative schemes were required by the nature of the radiative field and by the solid seed vaporization. Approximate formulations of the radiative heat flux are generally used, due to the complexity of the solution of a rigorously formulated problem. The present work analyzes the sensitivity of the results with respect to approximations of the radiative field, geometry, seed vaporization coefficients and flow pattern. The results present temperature, heat flux, density and optical depth distributions in the reactor cavity, acceptable simplifying assumptions, and iterative schemes. The present calculations, performed in cartesian and spherical coordinates, are applicable to any most general heat transfer problem.
Bottom-up heating method for producing polyethylene lunar concrete in lunar environment

NASA Astrophysics Data System (ADS)

Lee, Jaeho; Ann, Ki Yong; Lee, Tai Sik; Mitikie, Bahiru Bewket

2018-07-01

The Apollo Program launched numerous missions to the Moon, Earth's nearest and only natural satellite. NASA is now planning new Moon missions as a first step toward human exploration of Mars and other planets. However, the Moon has an extreme environment for humans. In-situ resource utilization (ISRU) construction must be used on the Moon to build habitable structures. Previous studies on polymeric lunar concrete investigated top-down heating for stabilizing the surface. This study investigates bottom-up heating with manufacturing temperatures as low as 200 °C in a vacuum chamber that simulates the lunar environment. A maximum compressive strength of 5.7 MPa is attained; this is suitable for constructing habitable structures. Furthermore, the bottom-up heating approach achieves solidification two times faster than does the top-down heating approach.
Evolution of aging: individual life history trade-offs and population heterogeneity account for mortality patterns across species.

PubMed

Le Cunff, Y; Baudisch, A; Pakdaman, K

2014-08-01

A broad range of mortality patterns has been documented across species, some even including decreasing mortality over age. Whether there exist a common denominator to explain both similarities and differences in these mortality patterns remains an open question. The disposable soma theory, an evolutionary theory of aging, proposes that universal intracellular trade-offs between maintenance/lifespan and reproduction would drive aging across species. The disposable soma theory has provided numerous insights concerning aging processes in single individuals. Yet, which specific population mortality patterns it can lead to is still largely unexplored. In this article, we propose a model exploring the mortality patterns which emerge from an evolutionary process including only the disposable soma theory core principles. We adapt a well-known model of genomic evolution to show that mortality curves producing a kink or mid-life plateaus derive from a common minimal evolutionary framework. These mortality shapes qualitatively correspond to those of Drosophila melanogaster, Caenorhabditis elegans, medflies, yeasts and humans. Species evolved in silico especially differ in their population diversity of maintenance strategies, which itself emerges as an adaptation to the environment over generations. Based on this integrative framework, we also derive predictions and interpretations concerning the effects of diet changes and heat-shock treatments on mortality patterns. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
Aerothermodynamic Environment Definition for the Genesis Sample Return Capsule

NASA Technical Reports Server (NTRS)

Cheatwood, F. McNeil; Merski, N. Ronald, Jr.; Riley, Christopher J.; Mitcheltree, Robert A.

2001-01-01

NASA's Genesis sample return mission will be the first to return material from beyond the Earth-Moon system. NASA Langley Research Center supported this mission with aerothermodynamic analyses of the sample return capsule. This paper provides an overview of that effort. The capsule is attached through its forebody to the spacecraft bus. When the attachment is severed prior to Earth entry, forebody cavities remain. The presence of these cavities could dramatically increase the heating environment in their vicinity and downstream. A combination of computational fluid dynamics calculations and wind tunnel phosphor thermography tests were employed to address this issue. These results quantify the heating environment in and around the cavities, and were a factor in the decision to switch forebody heat shield materials. A transition map is developed which predicts that the flow aft of the penetrations will still be laminar at the peak heating point of the trajectory. As the vehicle continues along the trajectory to the peak dynamic pressure point, fully turbulent flow aft of the penetrations could occur. The integrated heat load calculations show that a heat shield sized to the stagnation point levels will be adequate for the predicted environment aft of the penetrations.
Experimental study on flame pattern formation and combustion completeness in a radial microchannel

NASA Astrophysics Data System (ADS)

Fan, Aiwu; Minaev, Sergey; Kumar, Sudarshan; Liu, Wei; Maruta, Kaoru

2007-12-01

Combustion behavior in a radial microchannel with a gap of 2.0 mm and a diameter of 50 mm was experimentally investigated. In order to simulate the heat recirculation, which is an essential strategy in microscale combustion devices, positive temperature gradients along the radial flow direction were given to the microchannel by an external heat source. A methane-air mixture was supplied from the center of the top plate through a 4.0 mm diameter delivery tube. A variety of flame patterns, including a stable circular flame and several unstable flame patterns termed unstable circular flame, single and double pelton-like flames, traveling flame and triple flame, were observed in the experiments. The regime diagram of all these flame patterns is presented in this paper. Some characteristics of the various flame patterns, such as the radii of stable and unstable circular flames, major combustion products and combustion efficiencies of all these flame patterns, were also investigated. Furthermore, the effect of the heat recirculation on combustion stability was studied by changing the wall temperature levels.
Vapor Flow Patterns During a Start-Up Transient in Heat Pipes

NASA Technical Reports Server (NTRS)

Issacci, F.; Ghoniem, N, M.; Catton, I.

1996-01-01

The vapor flow patterns in heat pipes are examined during the start-up transient phase. The vapor core is modelled as a channel flow using a two dimensional compressible flow model. A nonlinear filtering technique is used as a post process to eliminate the non-physical oscillations of the flow variables. For high-input heat flux, multiple shock reflections are observed in the evaporation region. The reflections cause a reverse flow in the evaporation and circulations in the adiabatic region. Furthermore, each shock reflection causes a significant increase in the local pressure and a large pressure drop along the heat pipe.
Tidal Dissipation Within the Jupiter Moon Io - A Numerical Approach

NASA Astrophysics Data System (ADS)

Steinke, Teresa; van der Wal, Wouter; Hu, Haiyang; Vermeersen, Bert

2017-04-01

Satellite images and recent Earth-based observations of the innermost of the Galilean moons reveal a conspicuous pattern of volcanic hotspots and paterae on its surface. This pattern is associated with the heat flux originating from tidal dissipation in Io's mantle and asthenosphere. As shown by many analytical studies [e.g. Segatz et al. 1988], the local heat flux pattern depends on the rheology and structure of the satellite's interior and therefore could reveal constraints on Io's present interior. However, non-linear processes, different rheologies, and in particular lateral variations arising from the spatial heating pattern are difficult to incorporate in analytical 1D models but might be crucial. This motivates the development of a 3D finite element model of a layered body disturbed by a tidal potential. As a first step of this project we present a 3D finite element model of a spherically stratified body of linear viscoelastic rheology. For validation, we compare the resulting tidal deformation and local heating patterns with the results obtained by analytical models. Numerical errors increase with lower values of the asthenosphere viscosity. Currently, the numerical model allows realistic simulation down to viscosities of 1018 Pa s. Furthermore, we investigate an adequate way to deal with the relaxation of false modes that arise at the onset of the periodic tidal potential series in the numerical approach. Segatz, M., Spohn, T., Ross, M. N., Schubert, G. (1988). Tidal dissipation, surface heat flow, and figure of viscoelastic models of Io. Icarus, 75(2), 187-206.
Prediction of the Aerothermodynamic Environment of the Huygens Probe

NASA Technical Reports Server (NTRS)

Hollis, Brian R.; Striepe, Scott A.; Wright, Michael J.; Bose, Deepak; Sutton, Kenneth; Takashima, Naruhisa

2005-01-01

An investigation of the aerothermodynamic environment of the Huygens entry probe has been conducted. A Monte Carlo simulation of the trajectory of the probe during entry into Titan's atmosphere was performed to identify a worst-case heating rate trajectory. Flowfield and radiation transport computations were performed at points along this trajectory to obtain convective and radiative heat-transfer distributions on the probe's heat shield. This investigation identified important physical and numerical factors, including atmospheric CH4 concentration, transition to turbulence, numerical diffusion modeling, and radiation modeling, which strongly influenced the aerothermodynamic environment.
Arabidopsis gene expression patterns are altered during spaceflight

NASA Astrophysics Data System (ADS)

Paul, Anna-Lisa; Popp, Michael P.; Gurley, William B.; Guy, Charles; Norwood, Kelly L.; Ferl, Robert J.

The exposure of Arabidopsis thaliana (Arabidopsis) plants to spaceflight environments results in differential gene expression. A 5-day mission on orbiter Columbia in 1999 (STS-93) carried transgenic Arabidopsis plants engineered with a transgene composed of the alcohol dehydrogenase (Adh) gene promoter linked to the β-Glucuronidase (GUS) reporter gene. The plants were used to evaluate the effects of spaceflight on gene expression patterns initially by using the Adh/GUS transgene to address specifically the possibility that spaceflight induces a hypoxic stress response (Paul, A.L., Daugherty, C.J., Bihn, E.A., Chapman, D.K., Norwood, K.L., Ferl, R.J., 2001. Transgene expression patterns indicate that spaceflight affects stress signal perception and transduction in arabidopsis, Plant Physiol. 126, 613-621). As a follow-on to the reporter gene analysis, we report here the evaluation of genome-wide patterns of native gene expression within Arabidopsis shoots utilizing the Agilent DNA array of 21,000 Arabidopsis genes. As a control for the veracity of the array analyses, a selection of genes was further characterized with quantitative Real-Time RT PCR (ABI - Taqman®). Comparison of the patterns of expression for arrays probed with RNA isolated from plants exposed to spaceflight compared to RNA isolated from ground control plants revealed 182 genes that were differentially expressed in response to the spaceflight mission by more than 4-fold, and of those only 50 genes were expressed at levels chosen to support a conservative change call. None of the genes that are hallmarks of hypoxic stress were induced to this level. However, genes related to heat shock were dramatically induced - but in a pattern and under growth conditions that are not easily explained by elevated temperatures. These gene expression data are discussed in light of current models for plant responses to the spaceflight environment and with regard to potential future spaceflight experiment opportunities.
Experimental and modeling study of thermal exposure of a self-contained breathing apparatus (SCBA).

PubMed

Donnelly, Michelle K; Yang, Jiann C

2015-08-01

An experimental apparatus designed to study firefighter safety equipment exposed to a thermal environment was developed. The apparatus consisted of an elevated temperature flow loop with the ability to heat the air stream up to 200°C. The thermal and flow conditions at the test section were characterized using thermocouples and bi-directional probes. The safety equipment examined in this study was a self-contained breathing apparatus (SCBA), including a facepiece and an air cylinder. The SCBA facepiece was placed on a mannequin headform and coupled to a breathing simulator that was programmed with a prescribed breathing pattern. The entire SCBA assembly was placed in the test section of the flow loop for these thermal exposure experiments. Three air stream temperatures, 100°C, 150°C, and 200°C, were used with the average air speed at the test section set at 1.4m/s and thermal exposure durations up to 1200 s. Measurements were made using type-K bare-bead thermocouples located in the mannequin's mouth and on the outer surface of the SCBA cylinder. The experimental results indicated that increasing the thermal exposure severity and duration increased the breathing air temperatures supplied by the SCBA. Temperatures of breathing air from the SCBA cylinder in excess of 60°C were observed over the course of the thermal exposure conditions used in most of the experiments. A mathematical model for transient heat transfer was developed to complement the thermal exposure experimental study. The model took into consideration forced convective heat transfer, quasi-steady heat conduction through the composite layers of the SCBA cylinder wall, the breathing pattern and action of the breathing simulator, and predicted air temperatures from the thermally exposed SCBA cylinder and temperatures at the outer surface of the SCBA cylinder. Model predictions agreed reasonably well with the experimental measurements. Published by Elsevier Ltd.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Kitada, Toshihiro; Okamura, Kiyoshi; Tanaka, Setsu

Japanese large cities, mostly located in coastal region, have rapidly expanded in the last three decades. People in the region now experience warmer and unpleasant thermal environment in summer season, supposedly because of the extensive urbanization. Especially, under fine weather with light synoptic-scale gradient wind, the highest temperature often appears in rather inland area. An explanation to this phenomenon is horizontal transport of heat by the sea breeze which is strongly heated during its passage over the coastal urban area. This study investigated how and how much urbanization in Nohbi Plain of central Japan influences local wind and temperature distributionmore » over the plain and its surrounding region, Nohbi Plain which faces to the Pacific Ocean and is surrounded by the Japanese Alps, and thus is in a typical topographic situation in Japan. For the study we performed numerical simulations using our meso-scale meteorological model which includes k-c model for turbulence. One of the major results obtained is to have clarified a hierarchy in natural and artificial topography of various scales on their contributions to formation of characteristic diurnal pattern of wind and temperature distributions in the plain area. The Japanese Alps, the largest topographic feature in central Japan and often called the roof of Japan, gave the most important influence on the wind, although the mountains are located quite far, around 200 km, from Nohbi Plain. The way for the influence of the high mountains was to warm air mass in upper layer but below 2 km in altitude, over the Nohbi Plain through heat transport due to a large scale circulation consisting of the {open_quotes}flows from plain to plateau in lower layer and plateau to plain in upper layer{close_quotes}. Urbanization in the coastal Nohbi Plain showed little effect on the flow pattern, but caused large temperature rises at surface level in the inland area because of horizontal heat transfer by the sea breeze.« less
A Simplified Approach for the Rapid Generation of Transient Heat-Shield Environments

NASA Technical Reports Server (NTRS)

Wurster, Kathryn E.; Zoby, E. Vincent; Mills, Janelle C.; Kamhawi, Hilmi

2007-01-01

A simplified approach has been developed whereby transient entry heating environments are reliably predicted based upon a limited set of benchmark radiative and convective solutions. Heating, pressure and shear-stress levels, non-dimensionalized by an appropriate parameter at each benchmark condition are applied throughout the entry profile. This approach was shown to be valid based on the observation that the fully catalytic, laminar distributions examined were relatively insensitive to altitude as well as velocity throughout the regime of significant heating. In order to establish a best prediction by which to judge the results that can be obtained using a very limited benchmark set, predictions based on a series of benchmark cases along a trajectory are used. Solutions which rely only on the limited benchmark set, ideally in the neighborhood of peak heating, are compared against the resultant transient heating rates and total heat loads from the best prediction. Predictions based on using two or fewer benchmark cases at or near the trajectory peak heating condition, yielded results to within 5-10 percent of the best predictions. Thus, the method provides transient heating environments over the heat-shield face with sufficient resolution and accuracy for thermal protection system design and also offers a significant capability to perform rapid trade studies such as the effect of different trajectories, atmospheres, or trim angle of attack, on convective and radiative heating rates and loads, pressure, and shear-stress levels.
The Heat Exposure Integrated Deprivation Index (HEIDI): A data-driven approach to quantifying neighborhood risk during extreme hot weather.

PubMed

Krstic, Nikolas; Yuchi, Weiran; Ho, Hung Chak; Walker, Blake B; Knudby, Anders J; Henderson, Sarah B

2017-12-01

Mortality attributable to extreme hot weather is a growing concern in many urban environments, and spatial heat vulnerability indexes are often used to identify areas at relatively higher and lower risk. Three indexes were developed for greater Vancouver, Canada using a pool of 20 potentially predictive variables categorized to reflect social vulnerability, population density, temperature exposure, and urban form. One variable was chosen from each category: an existing deprivation index, senior population density, apparent temperature, and road density, respectively. The three indexes were constructed from these variables using (1) unweighted, (2) weighted, and (3) data-driven Heat Exposure Integrated Deprivation Index (HEIDI) approaches. The performance of each index was assessed using mortality data from 1998-2014, and the maps were compared with respect to spatial patterns identified. The population-weighted spatial correlation between the three indexes ranged from 0.68-0.89. The HEIDI approach produced a graduated map of vulnerability, whereas the other approaches primarily identified areas of highest risk. All indexes performed best under extreme temperatures, but HEIDI was more useful at lower thresholds. Each of the indexes in isolation provides valuable information for public health protection, but combining the HEIDI approach with unweighted and weighted methods provides richer information about areas most vulnerable to heat. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
Temporal and seasonal variations of black carbon in a highly polluted European city: Apportionment of potential sources and the effect of meteorological conditions.

PubMed

Kucbel, Marek; Corsaro, Agnieszka; Švédová, Barbora; Raclavská, Helena; Raclavský, Konstantin; Juchelková, Dagmar

2017-12-01

Black carbon - a primary component of particulate matter emitted from an incomplete combustion of fossil fuels, biomass, and biofuels - has been found to have a detrimental effect on human health and the environment. Since black carbon emissions data are not readily available, no measures are implemented to reduce black carbon emissions. The temporal and seasonal variations of black carbon concentrations were evaluated during 2012-2014. The data were collected in the highly polluted European city - Ostrava, Czech Republic, surrounded by major highways and large industries. Significantly higher black carbon concentrations were obtained in Ostrava, relative to other European cities and the magnitude was equivalent to the magnitude of black carbon concentrations measured in Poland and China. The data were categorized to heating and non-heating seasons based on the periodic pattern of daily and monthly average concentrations of black carbon. A higher black carbon concentration was obtained during heating season than non-heating season and was primarily associated with an increase in residential coal burning and meteorological parameters. The concentration of black carbon was found to be negatively correlated with temperature and wind speed, and positively correlated with the relative humidity. Other black carbon sources potentially included emissions from vehicle exhaust and the local steel-producing industry. Copyright © 2017 Elsevier Ltd. All rights reserved.
SRB ascent aerodynamic heating design criteria reduction study, volume 2

NASA Technical Reports Server (NTRS)

Crain, W. K.; Frost, C. L.; Engel, C. D.

1989-01-01

Data are presented for the wind tunnel interference heating factor data base, the timewise tabulated ascent design environments, and the timewise plotted environments comparing the REMTECH results to the Rockwell RI-IVBC-3 results.
Thermal equilibrium of Nellore cattle in tropical conditions: an investigation of circadian pattern.

PubMed

de Melo Costa, Cíntia Carol; Campos Maia, Alex Sandro; Brown-Brandl, Tami M; Chiquitelli Neto, Marcos; de França Carvalho Fonsêca, Vinicius

2018-05-01

The aim of this work was to evaluate the diurnal patterns of physiological responses and the thermal regulation of adult Nellore bulls. Six 30-mo-old Nellore bulls (669 ± 65 kg BW) were randomly assigned to four 6-h periods in a Latin Square design such that measurements of each animal cover a 24-h cycle. Meteorological variables (air temperature, relative humidity, local solar irradiance, ultraviolet radiation, wind speed and black globe temperature) were recorded at regular one-minute intervals with an automated weather station. Respiratory rate, ventilation rate, oxygen, carbon dioxide, methane, saturation pressure, air temperature of the exhaled air, saturation pressure in the air leaving the ventilated capsule placed over the animal surface, hair coat, skin surface and rectal temperature were assessed. The thermal equilibrium was determined according to the principles of the first law of thermodynamics using biophysical equations. Animals were evaluated in an area which was protected from solar radiation, rain, and had a range of ambient air temperature between 20.57 ± 0.07 and 30.86 ± 0.07 °C. Percentage of O 2 and CO 2 in the exhaled air changed moderately (P < 0.0001) throughout the 24 h, which resulted in an average metabolic heat production of 151.45 ± 13.60 W m -2 . At the largest thermal gradient (T S - T A ; from 24:00-07:00 h), heat transferred by long wave radiation and surface convection corresponded to near 60% of the metabolism. At 11:00 h the ambient temperature approached 29 °C and latent heat became the main way to cool the body. From this time until 17:00 h, cutaneous evaporation represented approximately 53% of total heat loss. In conclusion, results of the present study seem to be a good indicator of lower energy expenditure for body thermal regulation, high heat tolerance and adaptation of Nellore cattle to the tropical environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heating and Cooling System Design for a Modern Transportable Container

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

Berger, Jason E.

Sandia National Laboratories (SNL) has been tasked with the design of a modern transportable container (MTC) for use in high reliability transportation environments. The container is required to transport cargo capable of generating its own heat and operate under the United States’ climatic extremes. In response to these requirements, active heating and cooling is necessary to maintain a controlled environment inside the container. The following thesis project documents the design of an active heating, active cooling, and combined active heating and cooling system (now referred to as active heating and cooling systems) through computational thermal analyses, scoping of commercial systemmore » options, and mechanical integration with the container’s structure.« less
The influence of PM2.5 coal power plant emissions on environment PM2.5 in Jilin Province, China

NASA Astrophysics Data System (ADS)

Sun, Ye; Li, Zhi; Zhang, Dan; Zhang, He; Zhang, Huafei

2018-02-01

In recent years, in the Northeast of China, the heating period comes with large range of haze weather. All the units of coal power plants in Jilin Province have completed the cogeneration reformation; they provide local city heat energy. Many people believe that coal power plants heating caused the heavy haze. In is paper, by compared concentration of PM2.5 in environment in heating period and non heating period, meanwhile the capacity of local coal power plants, conclude that the PM2.5 emission of coal power plants not directly cause the heavy haze in Changchun and Jilin in the end of October and early November. In addition, the water-soluble iron composition of PM2.5 coal power plant emissions is compared with environment, which further proves that the heating supply in coal power plants is not the cause of high concentration of PM2.5 in Jilin province.
Interactions between sire family and production environment (temperate vs. tropical) on performance and thermoregulation responses in growing pigs.

PubMed

Rosé, R; Gilbert, H; Loyau, T; Giorgi, M; Billon, Y; Riquet, J; Renaudeau, D; Gourdine, J-L

2017-11-01

The aim of this study was to evaluate the effect of 2 climatic environments (temperate [TEMP] vs. tropical humid [TROP]) on production and thermoregulation traits in growing pigs. A backcross design involving Large White (LW; heat sensitive) and Creole (CR; heat tolerant) pigs was studied. The same 10 F LW × CR boars were mated with related LW sows in each environment. A total of 1,298 backcross pigs ( = 634 pigs from 11 batches for the TEMP environment and = 664 pigs from 12 batches for the TROP environment) were phenotyped on BW (every 15 d from wk 11 to 23 of age), voluntary feed intake (ADFI, from wk 11 to 23), backfat thickness (BFT; at wk 19 and 23), skin temperature (ST; at wk 19 and 23), and rectal temperature (RT; at wk 19, 21, and 23). The feed conversion ratio was computed for the whole test period (11 to 23 wk). The calculation of the temperature-humidity index showed an average difference of 2.4°C between the TEMP and TROP environments. The ADG and ADFI were higher in the TEMP environment than in the TROP environment (834 vs. 754 g/d and 2.20 vs. 1.80 kg/d, respectively; < 0.001). Body temperatures were higher in the TROP environment than in the TEMP environment (35.9 vs. 34.8°C for ST and 39.5 vs. 39.3°C for RT, respectively; < 0.001). Most of the studied traits (i.e., BW, BFT, ADG, ADFI, and RT) were affected by sire family × environment interactions ( < 0.05), resulting in "robust" and "sensitive" families. Our results show a family dependency in the relationships between heat resistance and robustness, suggesting the possibility of finding genotypes with high production and low heat sensitivity. Further research is needed to confirm the genetic × environment interaction and to detect QTL related to heat tolerance.
Detecting Changes of Thermal Environment over the Bohai Coastal Region by Spectral Change Vector Analysis

NASA Astrophysics Data System (ADS)

Hu, Y.; Jia, G.

2009-12-01

Change vector analysis (CVA) is an effective approach for detecting and characterizing land-cover change by comparing pairs of multi-spectral and multi-temporal datasets over certain area derived from various satellite platforms. NDVI is considered as an effective detector for biophysical changes due to its sensitivity to red and near infrared signals, while land surface temperature (LST) is considered as a valuable indicator for changes of ground thermal conditions. Here we try to apply CVA over satellite derived LST datasets to detect changes of land surface thermal properties parallel to climate change and anthropogenic influence in a city cluster since 2001. In this study, monthly land surface temperature datasets from 2001-2008 derived from MODIS collection 5 were used to examine change pattern of thermal environment over the Bohai coastal region by using spectral change vector analysis. The results from principle component analysis (PCA) for LST show that the PC 1-3 contain over 80% information on monthly variations and these PCA components represent the main processes of land thermal environment change over the study area. Time series of CVA magnitude combined with land cover information show that greatest change occurred in urban and heavily populated area, featured with expansion of urban heat island, while moderate change appeared in grassland area in the north. However few changes were observed over large plain area and forest area. Strong signals also are related to economy level and especially the events of surface cover change, such as emergence of railway and port. Two main processes were also noticed about the changes of thermal environment. First, weak signal was detected in mostly natural area influenced by interannual climate change in temperate broadleaf forest area. Second, land surface temperature changes were controlled by human activities as 1) moderate change of LST happened in grassland influenced by grazing and 2) urban heat island was intensifier in major cities, such as Beijing and Tianjin. Further, the continual drier climate combined with human actions over past fifties years have intensified land thermal pattern change and the continuation will be an important aspects to understand land surface processes and local climate change. Land surface temperature trends from 2000-2008 over the Bohai coastal region
Preliminary base heating environments for a generalized ALS LO2/LH2 launch vehicle, appendix 1 and 2

NASA Technical Reports Server (NTRS)

Bender, Robert L.; Reardon, John E.

1989-01-01

A secondary objective of contract NAS8-39141 is to provide base heating assessments, as required, to support Advanced Launch System (ALS) preliminary launch vehicle and propulsion system design studies. The ALS propulsion systems integration working group meeting (No. 3) recently completed in San Diego, California, focused attention on the need for base heating environment determination to provide preliminary requirements for LO2/LH2 propulsion systems currently being considered for ALS. We were requested to provide these environments for a range of possible propellant mixture and nozzle area ratios. Base heating environments can only be determined as a function of altitude when the engine operating conditions and vehicle base region geometry (engine arrangement) are known. If time dependent environments are needed to assess thermal loads, a trajectory must also be provided. These parameters are not fixed at this time since the ALS configurations and propulsion operating conditions are varied and continue to be studied by Phase B contractors. Therefore, for this study, a generalized LO2/LH2 system was selected along with a vehicle configuration consisting of a seven-engine booster and a three-engine core. MSFC provided guidance for the selection. We also selected a limited number of body points on the booster and core vehicles and engines for the environment estimates. Environments at these locations are representative of maximum heating conditions in the base region and are provided as a function of altitude only. Guidelines and assumptions for this assessment, methodology for determining the environments, and preliminary results are provided in this technical note. Refinements in the environments will be provided as the ALS design matures.
Physiological Responses to Acute Exercise-Heat Stress

DTIC Science & Technology

1988-01-01

muscle contraction and to dissipate the associated heat release. In hot environments, the core to skin temperature gradient is reduced to skin blood flow needs to be relatively high (compared to cooler environments) to achieve heat transfer sufficient for thermal balance. In addition, sweat secretion can result in a reduced plasma (by dehydration) and thus blood volume. Both high skin blood flow and reduced plasma volume can reduce
The induction and decay of heat acclimatisation in trained athletes.

PubMed

Armstrong, L E; Maresh, C M

1991-11-01

Heat acclimatisation/acclimation involves a complex of adaptations which includes decreased heart rate, rectal temperature, perceived exertion as well as increased plasma volume and sweat rate. These adaptations serve to reduce physiological strain, improve an athlete's ability to exercise in a hot environment, and reduce the incidence of some forms of heat illness. Few differences exist in the ability of men and women to acclimatise to heat. Typically, older runners do not perform in the heat as well as younger runners, but physical training can negate differences between these groups. Hormonal adaptations (e.g. aldosterone, vasopressin) during heat acclimatisation encourage fluid-electrolyte retention and cardiovascular stability. Athletes with high maximal aerobic power (VO2max) acclimatise to heat faster (and lose adaptations slower when they are inactive in a cool environment) than athletes with low VO2max values. Physical training in a cool environment improves physiological responses to exercise at high ambient temperatures. In attempting to optimise heat acclimatisation, athletes should maintain fluid-electrolyte balance, exercise at intensities greater than 50% VO2max for 10 to 14 days, and avoid factors (e.g. sleep loss, infectious disease) which are known to reduce heat tolerance. Once acclimatisation has been achieved, inactivity results in a decay of favourable adaptations, after only a few days or weeks.
Work environment of Danish shift and day workers.

PubMed

Bøggild, H; Burr, H; Tüchsen, F; Jeppesen, H J

2001-04-01

Both shift work and other work environment factors have been shown to be related to heart disease. This study examined whether shift work is associated with other work environment factors related to heart disease in a random sample of the population. If so, shift work could be acting as a proxy for work environment differences. Data on 5940 employees in the Danish Work Environment Cohort Study from 1990 were reanalyzed. The information included work schedules [permanent day work, irregular workhours (including morning work), 2-shift or fixed evening and 3-shift or fixed night], length of workweek, physical factors (noise, heat, dust, passive smoking, walking, standing and monotonous repetitive tasks), and psychosocial factors (including demands and control dimensions, social support, conflicts and job insecurity). At least 1 group of shift workers had a higher prevalence of nearly every unfavorable work environment factor investigated. Exceptions were dust exposure and quantitative demands. Especially conflicts at work and low decision latitude were higher among all the groups of shift workers, and all-day walking or standing work and part-time jobs were more often found among female shift workers. The 3 different shiftwork groups were exposed to different parts of the work environment, and also men and women in shift work differed in relation to the work environment. Age and social class influenced the relationship, but not in any particular pattern. In a heterogenous population shift work was found to be associated with other work environment factors suspected to cause heart disease.
Frequency-selective near-field radiative heat transfer between photonic crystal slabs: a computational approach for arbitrary geometries and materials.

PubMed

Rodriguez, Alejandro W; Ilic, Ognjen; Bermel, Peter; Celanovic, Ivan; Joannopoulos, John D; Soljačić, Marin; Johnson, Steven G

2011-09-09

We demonstrate the possibility of achieving enhanced frequency-selective near-field radiative heat transfer between patterned (photonic-crystal) slabs at designable frequencies and separations, exploiting a general numerical approach for computing heat transfer in arbitrary geometries and materials based on the finite-difference time-domain method. Our simulations reveal a tradeoff between selectivity and near-field enhancement as the slab-slab separation decreases, with the patterned heat transfer eventually reducing to the unpatterned result multiplied by a fill factor (described by a standard proximity approximation). We also find that heat transfer can be further enhanced at selective frequencies when the slabs are brought into a glide-symmetric configuration, a consequence of the degeneracies associated with the nonsymmorphic symmetry group.
Compact acoustic refrigerator

DOEpatents

Bennett, G.A.

1992-11-24

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.
Variation in Thermal Sensitivity and Thermal Tolerances in an Invasive Species across a Climatic Gradient: Lessons from the Land Snail Cornu aspersum

PubMed Central

Gaitán-Espitia, Juan Diego; Belén Arias, María; Lardies, Marco A.; Nespolo, Roberto F.

2013-01-01

The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Inter-and intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e.g., critical and lethal limits), influencing the biogeographic patterns of species’ distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermal-coma recovery times, expression of heat-shock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the “hotter is better” and the generalist-specialist trade-offs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints (“hotter is better”) and thermal adaptations to their local environments (generalist-specialist trade-offs). This finding is also consistent with some thermal tolerance indices such as the Heat-Shock Protein Response and the recovery time from chill-coma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heat-coma recovery. PMID:23940617
Variation in thermal sensitivity and thermal tolerances in an invasive species across a climatic gradient: lessons from the land snail Cornu aspersum.

PubMed

Gaitán-Espitia, Juan Diego; Belén Arias, María; Lardies, Marco A; Nespolo, Roberto F

2013-01-01

The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Inter-and intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e.g., critical and lethal limits), influencing the biogeographic patterns of species' distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermal-coma recovery times, expression of heat-shock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the "hotter is better" and the generalist-specialist trade-offs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints ("hotter is better") and thermal adaptations to their local environments (generalist-specialist trade-offs). This finding is also consistent with some thermal tolerance indices such as the Heat-Shock Protein Response and the recovery time from chill-coma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heat-coma recovery.
The Role of Heat Tolerance Testing in Recovery and Return to Duty

DTIC Science & Technology

2008-10-01

CV diseases Hyperthyroidism Pheochromocytoma Infectious diseases Diabetes mellitus Psychiatric illness Parkinsonism Congenital abnormalities: CF...environments. To assess the heat tolerance status of prior heat stroke patient. Heat tolerance test (HTT) “HTT was effective in evaluating the heat tolerance
What are hot and what are not in an urban landscape: quantifying and explaining the land surface temperature pattern in Beijing, China

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

Kuang, Wenhui; Liu, Yue; Dou, Yinyin

Understanding how landscape components affect the urban heat islands is crucial for urban ecological planning and sustainable development. The purpose of this research was to quantify the spatial pattern of land surface temperatures (LSTs) and associated heat fluxes in relation to land-cover types in Beijing, China, using portable infrared thermometers, thermal infrared imagers, and the moderate resolution imaging spectroradiometer. The spatial differences and the relationships between LSTs and the hierarchical landscape structure were analyzed with in situ observations of surface radiation and heat fluxes. Large LST differences were found among various land-use/land-cover types, urban structures, and building materials. Within themore » urban area, the mean LST of urban impervious surfaces was about 6–12°C higher than that of the urban green space. LSTs of built-up areas were on average 3–6°C higher than LSTs of rural areas. The observations for surface radiation and heat fluxes indicated that the differences were caused by different fractions of sensible heat or latent heat flux in net radiation. LSTs decreased with increasing elevation and normalized difference vegetation index. Variations in building materials and urban structure significantly influenced the spatial pattern of LSTs in urban areas. By contrast, elevation and vegetation cover are the major determinants of the LST pattern in rural areas. In summary, to alleviate urban heat island intensity, urban planners and policy makers should pay special attention to the selection of appropriate building materials, the reasonable arrangement of urban structures, and the rational design of landscape components.« less
What are hot and what are not in an urban landscape: quantifying and explaining the land surface temperature pattern in Beijing, China

DOE PAGES

Kuang, Wenhui; Liu, Yue; Dou, Yinyin; ...

2014-12-06

Understanding how landscape components affect the urban heat islands is crucial for urban ecological planning and sustainable development. The purpose of this research was to quantify the spatial pattern of land surface temperatures (LSTs) and associated heat fluxes in relation to land-cover types in Beijing, China, using portable infrared thermometers, thermal infrared imagers, and the moderate resolution imaging spectroradiometer. The spatial differences and the relationships between LSTs and the hierarchical landscape structure were analyzed with in situ observations of surface radiation and heat fluxes. Large LST differences were found among various land-use/land-cover types, urban structures, and building materials. Within themore » urban area, the mean LST of urban impervious surfaces was about 6–12°C higher than that of the urban green space. LSTs of built-up areas were on average 3–6°C higher than LSTs of rural areas. The observations for surface radiation and heat fluxes indicated that the differences were caused by different fractions of sensible heat or latent heat flux in net radiation. LSTs decreased with increasing elevation and normalized difference vegetation index. Variations in building materials and urban structure significantly influenced the spatial pattern of LSTs in urban areas. By contrast, elevation and vegetation cover are the major determinants of the LST pattern in rural areas. In summary, to alleviate urban heat island intensity, urban planners and policy makers should pay special attention to the selection of appropriate building materials, the reasonable arrangement of urban structures, and the rational design of landscape components.« less
Thermal convection as a possible mechanism for the origin of polygonal structures on Pluto's surface

NASA Astrophysics Data System (ADS)

Vilella, Kenny; Deschamps, Frédéric

2017-05-01

High-resolution pictures of Pluto's surface obtained by the New Horizons spacecraft revealed, among other surface features, a large nitrogen ice glacier informally named Sputnik Planitia. The surface of this glacier is separated into a network of polygonal cells with a wavelength of ˜20-40 km. This network is similar to the convective patterns obtained under certain conditions by laboratory experiments, suggesting that it is the surface expression of thermal convection. Here we investigate the surface planform obtained for different convective systems in 3-D Cartesian geometry with different modes of heating and rheologies. We find that bottom heated systems, as assumed by previous studies, do not produce surface planforms consistent with the observed pattern. Alternatively, for a certain range of Rayleigh-Roberts number, RaH, a volumetrically heated system produces a surface planform similar to this pattern. We then combine scaling laws with values of RaH within its possible range to establish relationships between the critical parameters of Sputnik Planitia. In particular, our calculations indicate that the glacier thickness and the surface heat flux are in the ranges 2-10 km and 0.1-10 mW m-2, respectively. However, a difficulty is to identify a proper source of internal heating. We propose that the long-term variations of surface temperature caused by variations in Pluto's orbit over millions of years produces secular cooling equivalent to internal heating. We find that this source of heating is sufficient to trigger thermal convection, but additional investigations are needed to determine under which conditions it can produce surface patterns similar to those of Sputnik Planitia.
Age-related effects of heat stress on protective enzymes for peroxides and microsomal monooxygenase in rat liver.

PubMed Central

Ando, M; Katagiri, K; Yamamoto, S; Wakamatsu, K; Kawahara, I; Asanuma, S; Usuda, M; Sasaki, K

1997-01-01

To evaluate the age-related response of essential cell functions against peroxidative damage in hyperthermia, we studied the biochemical response to heat stress in both young and aged rats. Passive hyperthermia was immediately observed in rats after exposure to hot environments. In aged rats, the rectal temperature maintained thermal homeostasis and increased to the same degree as in young rats. In these aged animals, the damage from heat stress was more serious than in young animals. In aged rats under normal environmental conditions, hepatic cytosolic glutathione peroxidase (GSH peroxidase) activities were markedly higher than those activities in younger rats. Hepatic cytosolic GSH peroxidase activities were induced by heat stress in young rats but were decreased by hot environments in aged rats. Hepatic catalase activities in young rats were not affected by hot environments, whereas in aged rats, hepatic catalase activities were seriously decreased. Catalase activities in the kidney of aged rats were also reduced by hot environments. Lipid peroxidation in the liver was markedly induced in both young and aged rats. Because the protective enzymes for oxygen radicals in aged rats were decreased by hot environments, lipid peroxidation in the liver was highly induced. In aged rats, lipid peroxidation in intracellular structures such as mitochondria and microsomes was also markedly induced by hot environments. In both young and aged rats, hyperthermia greatly increased the development of hypertrophy and vacuolated degeneration in hepatic cells. In aged rats, both mitochondria and endoplasmic reticulum of the hepatic cells showed serious distortion in shape as a result of exposures to hot environments. Microsomal electron transport systems, such as cytochrome P450 monooxygenase activities, were seriously decreased by heat stress in aged rats but not in young rats. Although the mitochondrial electron transport systems were not affected by acute heat stress in young rats, their activities were simultaneously inhibited after long-lasting heat exposure. In isolated hepatic cells and polymorphonuclear leukocytes in animals, the 70-kDa heat shock-induced proteins were markedly increased by heat stress. In conclusion, the heat stress-inducible oxygen radical damage becomes more severe according to the age of rats. Because aging and hyperthermia have a synergistic effect on lipid peroxidation, protective enzyme activities for oxygen radicals may be essential for surviving and recovering from thermal injury in aged animals and also in humans. Images Figure 1. Figure 2. A Figure 2. B Figure 2. C Figure 2. D Figure 3. Figure 4. Figure 5. Figure 6. A Figure 6. B Figure 7. A Figure 7. B PMID:9294719
Chained nuclei and python pattern in skeletal muscle cells as histological markers for electrical injury.

PubMed

Tanaka, Hiroki; Okuda, Katsuhiro; Ohtani, Seiji; Asari, Masaru; Horioka, Kie; Isozaki, Shotaro; Hayakawa, Akira; Ogawa, Katsuhiro; Hiroshi, Shiono; Shimizu, Keiko

2018-05-01

Electrical injury is damage caused by an electrical current passing through the body. We have previously reported that irregular stripes crossing skeletal muscle fibers (python pattern) and multiple small nuclei arranged in the longitudinal direction of the muscle fibers (chained nuclear change) are uniquely observed by histopathological analysis in the skeletal muscle tissues of patients with electrical injury. However, it remains unclear whether these phenomena are caused by the electrical current itself or by the joule heat generated by the electric current passing through the body. To clarify the causes underlying these changes, we applied electric and heat injury to the exteriorized rat soleus muscle in situ. Although both the python pattern and chained nuclear change were induced by electric injury, only the python pattern was induced by heat injury. Furthermore, a chained nuclear change was induced in the soleus muscle cells by electric current flow in physiological saline at 40 °C ex vivo, but a python pattern was not observed. When the skeletal muscle was exposed to electrical injury in cardiac-arrested rats, a python pattern was induced within 5 h after cardiac arrest, but no chained nuclear change was observed. Therefore, a chained nuclear change is induced by an electrical current alone in tissues in vital condition, whereas a python pattern is caused by joule heat, which may occur shortly after death. The degree and distribution of these skeletal muscle changes may be useful histological markers for analyzing cases of electrical injury in forensic medicine. Copyright © 2017 Elsevier B.V. All rights reserved.
Effect of aerated concrete blockwork joints on the heat transfer performance uniformity

NASA Astrophysics Data System (ADS)

Pukhkal, Viktor; Murgul, Vera

2018-03-01

Analysis of data on the effect of joints of the aerated concrete blocks on the heat transfer uniformity of exterior walls was carried out. It was concluded, that the values of the heat transfer performance uniformity factor in the literature sources were obtained for the regular fragment of a wall construction by approximate addition of thermal conductivities. Heat flow patterns for the aerated concrete exterior walls amid different values of the thermal conductivity factors and design ambient air temperature of -26 °C were calculated with the use of "ELCUT" software for modelling of thermal patterns by finite element method. There were defined the values for the heat transfer performance uniformity factor, reduced total thermal resistance and heat-flux density for the exterior walls. The calculated values of the heat transfer performance uniformity factors, as a function of the coefficient of thermal conductivity of aerated concrete blocks, differ from the known data by a more rigorous thermal and physical substantiation.
Novel localized heating technique on centrifugal microfluidic disc with wireless temperature monitoring system.

PubMed

Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman

2015-01-01

Recent advances in the field of centrifugal microfluidic disc suggest the need for electrical interface in the disc to perform active biomedical assays. In this paper, we have demonstrated an active application powered by the energy harvested from the rotation of the centrifugal microfluidic disc. A novel integration of power harvester disc onto centrifugal microfluidic disc to perform localized heating technique is the main idea of our paper. The power harvester disc utilizing electromagnetic induction mechanism generates electrical energy from the rotation of the disc. This contributes to the heat generation by the embedded heater on the localized heating disc. The main characteristic observed in our experiment is the heating pattern in relative to the rotation of the disc. The heating pattern is monitored wirelessly with a digital temperature sensing system also embedded on the disc. Maximum temperature achieved is 82 °C at rotational speed of 2000 RPM. The technique proves to be effective for continuous heating without the need to stop the centrifugal motion of the disc.

Carbon Dioxide-Lubricant Two-Phase Flow Patterns in Small Horizontal Wetted Wall Channels: The Effects of Refrigerant/Lubricant Thermophysical Properties

ERIC Educational Resources Information Center

Seeton, Christopher John

2009-01-01

Microchannel heat exchangers are gaining popularity due to their ability to handle high pressures, reduce refrigerant charge, and reduce heat exchanger package size. These heat exchanger designs provide better heat exchange performance due to increased refrigerant side heat transfer coefficients and geometries that allow for a denser packing…
Heat pipes and use of heat pipes in furnace exhaust

DOEpatents

Polcyn, Adam D.

2010-12-28

An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.
78 FR 78962 - Criteria for a Recommended Standard; Occupational Exposure to Heat and Hot Environments; Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

.... Heat stress can result in heat-related illnesses such as heat stroke, heat exhaustion, heat cramps, or... related materials, visit http://www.regulations.gov and enter CDC-2013-0025 in the search field and click... hydration that should be considered? (4) Are there any additional risk factors for heat-related illnesses...
[Criteria for assessing severely hot environments: from the WBGT index to the PHS (predicted heat strain) model].

PubMed

d'Ambrosio, Francesca Romana; Palella, B I; Riccio, G; Alfano, G

2004-01-01

The present study deals with the main methods for assessment of hot environments: i.e., WBGT, SWreq and PHS. It is stressed how the WBGT index, which is strictly empirical, although a very practical tool for the assessment of the hot environments, can only be used for a rough evaluation of heat stress, and especially for a not very high metabolic rate (M<175 W/m2). On the contrary, the SWreq method, which is based on both subject-environment heat exchange and the effect of clothing, allows a better assessment of the work situation with a general reduction of the exposure limits with respect to WBGT, especially in non-uniform environments (ta not equal to tr). However, it should be noted that application of SWreq is required by the ISO standard 7243 when the WBGT limit values are exceeded. In this study interest was extensively focused on the "Predicted Heat Strain" method, highlighting via a special software the differences in heat stress assessment related to this new approach, which will be adopted by the ISO in the next revision of standard 7933. The PHS method, unlike SWreq, allows the prediction of the time-response of the main physiological variables of interest (i.e., skin temperature, core temperature and sweat rate). Moreover thanks to better modelling of heat exchanges, the PHS method allows account to be taken of both movement and clothing effects, resulting in even more reduced exposure.
Visualization and flow boiling heat transfer of hydrocarbons in a horizontal tube

NASA Astrophysics Data System (ADS)

Yang, Zhuqiang; Bi, Qincheng; Guo, Yong; Liu, Zhaohui; Yan, Jianguo

2013-07-01

Visualizations of a specific hydrocarbon fuel in a horizontal tube with 2.0 mm inside diameter were investigated. The experiments were conducted at mass velocity of 213.4, 426.5 and 640.2 kg/ (m2ṡs), diabatic lengths of 140, 240 and 420 mm under the pressure from 2.0-2.7 MPa. In the sub-pressure conditions, bubbly, intermittent, stratified-wave, churn and annular flow patterns were observed. The frictional pressure drops were also measured to distinguish the patterns. The development of flow patterns and frictional pressure drop were positively related to the mass velocity and the heat flux. However, the diabatic length of the tube takes an important part in the process. The residence time of the fluid does not only affect the transition of the patterns but influence the composition of the fuel manifested by the fuel color and carbon deposit. The special observational phenomenon was obtained for the supercritical pressure fluid. The flow in the tube became fuzzier and pressure drop changed sharply near the pseudocritical point. The flow boiling heat transfer characteristics of the hydrocarbons were also discussed respectively. The curve of critical heat flux about onset of nucleate boiling was plotted with different mass velocities and diabatic tube lengths. And heat transfer characteristics of supercritical fuel were proved to be better than that in subcritical conditions.
Development of advanced high-temperature heat flux sensors. Phase 2: Verification testing

NASA Technical Reports Server (NTRS)

Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

1985-01-01

A two-phase program is conducted to develop heat flux sensors capable of making heat flux measurements throughout the hot section of gas turbine engines. In Phase 1, three types of heat flux sensors are selected; embedded thermocouple, laminated, and Gardon gauge sensors. A demonstration of the ability of these sensors to operate in an actual engine environment is reported. A segmented liner of each of two combustors being used in the Broad Specification Fuels Combustor program is instrumented with the three types of heat flux sensors then tested in a high pressure combustor rig. Radiometer probes are also used to measure the radiant heat loads to more fully characterize the combustor environment. Test results show the heat flux sensors to be in good agreement with radiometer probes and the predicted data trends. In general, heat flux sensors have strong potential for use in combustor development programs.
The SRB heat shield: Aeroelastic stability during reentry

NASA Technical Reports Server (NTRS)

Ventres, C. S.; Dowell, E. H.

1977-01-01

Wind tunnel tests of a 3% scale model of the aft portion of the SRB equipped with partially scaled heat shields were conducted for the purpose of measuring fluctuating pressure levels in the aft skirt region. During these tests, the heat shields were observed to oscillate violently, the oscillations in some instances causing the heat shields to fail. High speed films taken during the tests reveal a regular pattern of waves in the fabric starting near the flow stagnation point and progressing around both sides of the annulus. The amplitude of the waves was too great, and their pattern too regular, for them to be attributed to the fluctuating pressure levels measured during the tests. The cause of the oscillations observed in the model heat shields, and whether or not similar oscillations will occur in the full scale SRB heat shield during reentry were investigated. Suggestions for modifying the heat shield so as to avoid the oscillations are provided, and recommendations are made for a program of vibration and wind tunnel tests of reduced-scale aeroelastic models of the heat shield.
Solid-state NMR and IR for the analysis of pharmaceutical solids: polymorphs of fosinopril sodium.

PubMed

Brittain, H G; Morris, K R; Bugay, D E; Thakur, A B; Serajuddin, A T

1993-01-01

The two polymorphic modifications of fosinopril sodium have been characterized as to their differences in melting behaviour, powder X-ray diffraction patterns, Fourier transform infrared spectra (FTIR), and solid-state 31P- and 13C-NMR spectra. The polymorphs were found to be enantiotropically related based upon melting point, heat of fusion, and solution mediated transformation data. Analysis of the solid-state FTIR and 13C-NMR data indicated that the environment of the acetal side chain of fosinopril sodium differed in two polymorphs, and that there might be cis-trans isomerization about the C6-N peptide bond. These conformational differences are postulated as the origin of the observed polymorphism.
Surface development of a brazing alloy during heat treatment-a comparison between UHV and APXPS

NASA Astrophysics Data System (ADS)

Rullik, L.; Johansson, N.; Bertram, F.; Evertsson, J.; Stenqvist, T.; Lundgren, E.

2018-01-01

In an attempt to bridge the pressure gap, APXPS was used to follow the surface development of an aluminum brazing sheet during heating in an ambient oxygen-pressure mimicking the environment of an industrial brazing furnace. The studied aluminum alloy brazing sheet is a composite material consisting of two aluminum alloy standards whose surface is covered with a native aluminum oxide film. To emphasize the necessity of studies of this system in ambient sample environments it is compared to measurements in UHV. Changes in thickness and composition of the surface oxide were followed after heating to 300 °C, 400 °C, and 500 °C. The two sets presented in this paper show that the surface development strongly depends on the environment the sample is heated in.
Heat exposure on farmers in northeast Ghana

NASA Astrophysics Data System (ADS)

Frimpong, Kwasi; Van Etten E J, Eddie; Oosthuzien, Jacques; Fannam Nunfam, Victor

2017-03-01

Environmental health hazards faced by farmers, such as exposure to extreme heat stress, are a growing concern due to global climate change, particularly in tropical developing countries. In such environments, farmers are considered to be a population at risk of environmental heat exposure. The situation is exacerbated due to their farming methods that involve the use of primitive equipment and hard manual labour conducted in full sunshine under hot and humid conditions. However, there is inadequate information about the extent of heat exposure to such farmers, both at the household and farm levels. This paper presents results from a study assessing environmental heat exposure on rural smallholder farmers in Bawku East, Northern Ghana. From January to December 2013, Lascar USB temperature and humidity sensors and a calibrated Questemp heat stress monitor were deployed to farms and homes of rural farmers at Pusiga in Bawku East to capture farmers' exposure to heat stress in both their living and working environments as they executed regular farming routines. The Lascar sensors have the capability to frequently, accurately and securely measure temperature and humidity over long periods. The Questemp heat stress monitor was placed in the same vicinity and showed strong correlations to Lascar sensors in terms of derived values of wet-bulb globe temperature (WBGT). The WBGT in the working environment of farmers peaked at 33.0 to 38.1 °C during the middle of the day in the rainy season from March to October and dropped to 14.0-23.7 °C in the early morning during this season. A maximum hourly WBGT of 28.9-37.5 °C (March-October) was recorded in the living environment of farmers, demonstrating little relief from heat exposure during the day. With these levels of heat stress, exposed farmers conducting physically demanding outdoor work risk suffering serious health consequences. The sustainability of manual farming practices is also under threat by such high levels of heat exposure.
Reexamination of METMAN, Recommendations on Enhancement of LCVG, and Development of New Concepts for EMU Heat Sink

NASA Technical Reports Server (NTRS)

Karimi, Amir

1990-01-01

METMAN is a 41-node transient metabolic computer code developed in 1970 and revised in 1989 by Lockheed Engineering and Sciences, Inc. This program relies on a mathematical model to predict the transient temperature distribution in a body influenced by metabolic heat generation and thermal interaction with the environment. A more complex 315-node model is also available that not only simulates the thermal response of a body exposed to a warm environment, but is also capable of describing the thermal response resulting from exposure to a cold environment. It is important to compare the two models for the prediction of the body's thermal response to metabolic heat generation and exposure to various environmental conditions. Discrepancies between the twi models may warrant an investigation of METMAN to ensure its validity for describing the body's thermal response in space environment. The Liquid Cooling and Ventilation Garment is a subsystem of the Extravehicular Mobility Unit (EMU). This garment, worn under the pressure suit, contains the liquid cooling tubing and gas ventilation manifolds; its purpose is to alleviate or reduce thermal stress resulting from metabolic heat generation. There is renewed interest in modifying this garment through identification of the locus of maximum heat transfer at body-liquid cooled tubing interface. The sublimator is a vital component of the Primary Life Support System (PLSS) in the EMU. It acts as a heat sink to remove heat and humidity from the gas ventilating circuit and the liquid cooling loop of the LCVG. The deficiency of the sublimator is that the ice, used as the heat sink, sublimates into space. There is an effort to minimize water losses in the feedwater circuit of the EMU. This requires developing new concepts to design an alternative heat sink system. Efforts are directed to review and verify the heat transfer formulation of the analytical model employed by METMAN. A conceptual investigation of regenerative non-venting heat-sink subsystem for the EMU is recommended.
Heat exposure on farmers in northeast Ghana.

PubMed

Frimpong, Kwasi; Van Etten E J, Eddie; Oosthuzien, Jacques; Fannam Nunfam, Victor

2017-03-01

Environmental health hazards faced by farmers, such as exposure to extreme heat stress, are a growing concern due to global climate change, particularly in tropical developing countries. In such environments, farmers are considered to be a population at risk of environmental heat exposure. The situation is exacerbated due to their farming methods that involve the use of primitive equipment and hard manual labour conducted in full sunshine under hot and humid conditions. However, there is inadequate information about the extent of heat exposure to such farmers, both at the household and farm levels. This paper presents results from a study assessing environmental heat exposure on rural smallholder farmers in Bawku East, Northern Ghana. From January to December 2013, Lascar USB temperature and humidity sensors and a calibrated Questemp heat stress monitor were deployed to farms and homes of rural farmers at Pusiga in Bawku East to capture farmers' exposure to heat stress in both their living and working environments as they executed regular farming routines. The Lascar sensors have the capability to frequently, accurately and securely measure temperature and humidity over long periods. The Questemp heat stress monitor was placed in the same vicinity and showed strong correlations to Lascar sensors in terms of derived values of wet-bulb globe temperature (WBGT). The WBGT in the working environment of farmers peaked at 33.0 to 38.1 °C during the middle of the day in the rainy season from March to October and dropped to 14.0-23.7 °C in the early morning during this season. A maximum hourly WBGT of 28.9-37.5 °C (March-October) was recorded in the living environment of farmers, demonstrating little relief from heat exposure during the day. With these levels of heat stress, exposed farmers conducting physically demanding outdoor work risk suffering serious health consequences. The sustainability of manual farming practices is also under threat by such high levels of heat exposure.
Characteristics of Evaporator with a Lipuid-Vapor Separator

NASA Astrophysics Data System (ADS)

Ikeguchi, Masaki; Tanaka, Naoki; Yumikura, Tsuneo

Flow pattern of refrigerant in a heat exchanger tube changes depending on vapor quality, tube diameter, refrigerant flow rate and refrigerant properties. High flow rate causes mist flow where the quality is from 0.8 to 1.0. 1n this flow pattern, the liquid film detaches from the tube wall so that the heat flow is intervened. The heat transfer coefficient generally increases with the flow rate. But the pressure drop of refrigerant flow simultaneously increases and the region of the mist flow enlarges. In order to reduce the pressure drop and suppress the mist flow, we have developped a small liquid-vapor separator that removes the vapor from the evaporating refrigerant flow. This separator is equipped in the middle of the evaporator where the flow pattern is annular. The experiments to evaluate the effect of this separator were carried out and the following conclutions were obtained. (1) Average heat transfer coefficient increases by 30-60 %. (2) Pressure drop reduces by 20-30 %. (3) Cooling Capacity increases by 2-9 %.
Preliminary demonstration using localized skin temperature elevation as observed with thermal imaging as an indicator of fat-specific absorption during focused-field radiofrequency therapy.

PubMed

Key, Douglas J

2014-07-01

This study incorporates concurrent thermal camera imaging as a means of both safely extending the length of each treatment session within skin surface temperature tolerances and to demonstrate not only the homogeneous nature of skin surface temperature heating but the distribution of that heating pattern as a reflection of localization of subcutaneous fat distribution. Five subjects were selected because of a desire to reduce abdomen and flank fullness. Full treatment field thermal camera imaging was captured at 15 minute intervals, specifically at 15, 30, and 45 minutes into active treatment with the purpose of monitoring skin temperature and avoiding any patterns of skin temperature excess. Peak areas of heating corresponded anatomically to the patients' areas of greatest fat excess ie, visible "pinchable" fat. Preliminary observation of high-resolution thermal camera imaging used concurrently with focused field RF therapy show peak skin heating patterns overlying the areas of greatest fat excess.
Two-Phase Flow in Microchannels with Non-Circular Cross Section

NASA Astrophysics Data System (ADS)

Eckett, Chris A.; Strumpf, Hal J.

2002-11-01

Two-phase flow in microchannels is of practical importance in several microgravity space technology applications. These include evaporative and condensing heat exchangers for thermal management systems and vapor cycle systems, phase separators, and bioreactors. The flow passages in these devices typically have a rectangular cross-section or some other non-circular cross-section; may include complex flow paths with branches, merges and bends; and may involve channel walls of different wettability. However, previous experimental and analytical investigations of two-phase flow in reduced gravity have focussed on straight, circular tubes. This study is an effort to determine two-phase flow behavior, both with and without heat transfer, in microchannel configurations other than straight, circular tubes. The goals are to investigate the geometrical effects on flow pattern, pressure drop and liquid holdup, as well as to determine the relative importance of capillary, surface tension, inertial, and gravitational forces in such geometries. An evaporative heat exchanger for microgravity thermal management systems has been selected as the target technology in this investigation. Although such a heat exchanger has never been developed at Honeywell, a preliminary sizing has been performed based on knowledge of such devices in normal gravity environments. Fin shapes considered include plain rectangular, offset rectangular, and wavy fin configurations. Each of these fin passages represents a microchannel of non-circular cross section. The pans at the inlet and outlet of the heat exchanger are flow branches and merges, with up to 90-deg bends. R-134a has been used as the refrigerant fluid, although ammonia may well be used in the eventual application.
Tank Pressure Control Experiment: Thermal Phenomena in Microgravity. Video 3 of 4

NASA Technical Reports Server (NTRS)

1996-01-01

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

NASA Technical Reports Server (NTRS)

1996-01-01

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

NASA Technical Reports Server (NTRS)

1996-01-01

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

NASA Technical Reports Server (NTRS)

1996-01-01

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

NASA Astrophysics Data System (ADS)

Greenberg, R.

2001-11-01

Celestial mechanics is responsible for Jupiter's satellite Europa being a possible site for life in the solar system. The Laplace orbital resonance drives a substantial eccentricity. The mutually dependent relationship between orbital and rotational evolution and tidal processes in turn controls Europa's heating and stress. Heat is likely adequate to maintain a liquid water ocean, and to keep the surface ice thin. Tidal stress can explain characteristic and ubiquitous crack patterns (global and cycloidal), as well as drive observed shear displacement features. The characteristic ridge sets that cover tectonic terrain are likely built by tidal pumping of oceanic fluid and slush through cracks to the surface on a daily basis. Nearly half the surface is chaotic terrain, with morphology and other characteristics indicative of melt-through from below. Formation of both chaotic and tectonic terrains has continually resurfaced the satellite, while connecting the ocean to the surface and providing a variety of evolving environmental niches. As a result of tides, liquid water would daily bathe crustal cracks and surfaces with heat, transporting and mixing substances vertically. Thus a variety of habitable environments likely exist in the crust. Moreover, exposure of the ocean to the surface in the ways described here satisfies a necessary condition for life in the ocean as well, by providing access to oxidants which are available near the surface. These processes were recent, and thus most likely continue today. Longer term changes in environmental conditions in the crust, such as deactivation of individual cracks after thousands of years (due to non-synchronous rotation) and later crustal thawing (releasing any trapped organisms), provided drivers for adaptation, as well as opportunity for evolution. This work is supported by the NASA Planetary Geology and Geophysics Program and the NSF Life in Extreme Environments Program.

X-33 Experimental Aeroheating at Mach 6 Using Phosphor Thermography

NASA Technical Reports Server (NTRS)

Horvath, Thomas J.; Berry, Scott A.; Hollis, Brian R.; Liechty, Derek S.; Hamilton, H. Harris, II; Merski, N. Ronald

1999-01-01

The goal of the NASA Reusable Launch Vehicle (RLV) technology program is to mature and demonstrate essential, cost effective technologies for next generation launch systems. The X-33 flight vehicle presently being developed by Lockheed Martin is an experimental Single Stage to Orbit (SSTO) demonstrator that seeks to validate critical technologies and insure applicability to a full scale RLV. As with the design of any hypersonic vehicle, the aeroheating environment is an important issue and one of the key technologies being demonstrated on X-33 is an advanced metallic Thermal Protection System (TPS). As part of the development of this TPS system, the X-33 aeroheating environment is being defined through conceptual analysis, ground based testing, and computational fluid dynamics. This report provides an overview of the hypersonic aeroheating wind tunnel program conducted at the NASA Langley Research Center in support of the ground based testing activities. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.013 scale (10-in.) ceramic models of the proposed X-33 configuration in Mach 6 air. The test parametrics include angles of attack from -5 to 40 degs, unit Reynolds numbers from 1x106 to 8x106/ft, and body flap deflections of 0, 10, and 20 deg. Experimental and computational results indicate the presence of shock/shock interactions that produced localized heating on the deflected flaps and boundary layer transition on the canted fins. Comparisons of the experimental data to laminar and turbulent predictions were performed. Laminar windward heating data from the wind tunnel was extrapolated to flight surface temperatures and generally compared to within 50 deg F of flight prediction along the centerline. When coupled with the phosphor technique, this rapid extrapolation method would serve as an invaluable TPS design tool.
Evolution of solidification texture during additive manufacturing.

PubMed

Wei, H L; Mazumder, J; DebRoy, T

2015-11-10

Striking differences in the solidification textures of a nickel based alloy owing to changes in laser scanning pattern during additive manufacturing are examined based on theory and experimental data. Understanding and controlling texture are important because it affects mechanical and chemical properties. Solidification texture depends on the local heat flow directions and competitive grain growth in one of the six <100> preferred growth directions in face centered cubic alloys. Therefore, the heat flow directions are examined for various laser beam scanning patterns based on numerical modeling of heat transfer and fluid flow in three dimensions. Here we show that numerical modeling can not only provide a deeper understanding of the solidification growth patterns during the additive manufacturing, it also serves as a basis for customizing solidification textures which are important for properties and performance of components.
Physiological and performance responses to a training camp in the heat in professional Australian football players.

PubMed

Racinais, Sebastien; Buchheit, Martin; Bilsborough, Johann; Bourdon, Pitre C; Cordy, Justin; Coutts, Aaron J

2014-07-01

To examine the physiological and performance responses to a heat-acclimatization camp in highly trained professional team-sport athletes. Eighteen male Australian Rules Football players trained for 2 wk in hot ambient conditions (31-33°C, humidity 34-50%). Players performed a laboratory-based heat-response test (24-min walk + 24 min seated; 44°C), a YoYo Intermittent Recovery Level 2 Test (YoYoIR2; indoor, temperate environment, 23°C) and standardized training drills (STD; outdoor, hot environment, 32°C) at the beginning and end of the camp. The heat-response test showed partial heat acclimatization (eg, a decrease in skin temperature, heart rate, and sweat sodium concentration, P < .05). In addition, plasma volume (PV, CO rebreathing, +2.68 [0.83; 4.53] mL/kg) and distance covered during both the YoYoIR2 (+311 [260; 361] m) and the STD (+45.6 [13.9; 77.4] m) increased postcamp (P < .01). None of the performance changes showed clear correlations with PV changes (r < .24), but the improvements in running STD distance in hot environment were correlated with changes in hematocrit during the heat-response test (r = -.52, 90%CI [-.77; -.12]). There was no clear correlation between the performance improvements in temperate and hot ambient conditions (r < .26). Running performance in both hot and temperate environments was improved after a football training camp in hot ambient conditions that stimulated heat acclimatization. However, physiological and performance responses were highly individual, and the absence of correlations between physical-performance improvements in hot and temperate environments suggests that their physiological basis might differ.
Genotypic diversity of stress response in Lactobacillus plantarum, Lactobacillus paraplantarum and Lactobacillus pentosus.

PubMed

Ricciardi, Annamaria; Parente, Eugenio; Guidone, Angela; Ianniello, Rocco Gerardo; Zotta, Teresa; Abu Sayem, S M; Varcamonti, Mario

2012-07-02

Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus paraplantarum are three closely related species which are widespread in food and non-food environments, and are important as starter bacteria or probiotics. In order to evaluate the phenotypic diversity of stress tolerance in the L. plantarum group and the ability to mount an adaptive heat shock response, the survival of exponential and stationary phase and of heat adapted exponential phase cells of six L. plantarum subsp. plantarum, one L. plantarum subsp. argentoratensis, one L. pentosus and two L. paraplantarum strains selected in a previous work upon exposure to oxidative, heat, detergent, starvation and acid stresses was compared to that of the L. plantarum WCFS1 strain. Furthermore, to evaluate the genotypic diversity in stress response genes, ten genes (encoding for chaperones DnaK, GroES and GroEL, regulators CtsR, HrcA and CcpA, ATPases/proteases ClpL, ClpP, ClpX and protease FtsH) were amplified using primers derived from the WCFS1 genome sequence and submitted to restriction with one or two endonucleases. The results were compared by univariate and multivariate statistical methods. In addition, the amplicons for hrcA and ctsR were sequenced and compared by multiple sequence alignment and polymorphism analysis. Although there was evidence of a generalized stress response in the stationary phase, with increase of oxidative, heat, and, to a lesser extent, starvation stress tolerance, and for adaptive heat stress response, with increased tolerance to heat, acid and detergent, different growth phases and adaptation patterns were found. Principal component analysis showed that while heat, acid and detergent stresses respond similarly to growth phase and adaptation, tolerance to oxidative and starvation stresses implies completely unrelated mechanisms. A dendrogram obtained using the data from multilocus restriction typing (MLRT) of stress response genes clearly separated two groups of L. plantarum strains from the other species but there was no correlation between genotypic grouping and grouping obtained on the basis of the stress response pattern, nor with the phylograms obtained from hrcA and ctsR sequences. Differences in sequence in L. plantarum strains were mostly due to single nucleotide polymorphisms with a high frequency of synonymous nucleotide changes and, while hrcA was characterized by an excess of low frequency polymorphism, very low diversity was found in ctsR sequences. Sequence alignment of hrcA allowed a correct discrimination of the strains at the species level, thus confirming the relevance of stress response genes for taxonomy. Copyright © 2012 Elsevier B.V. All rights reserved.
Global Climatic Controls On Leaf Size

NASA Astrophysics Data System (ADS)

Wright, I. J.; Prentice, I. C.; Dong, N.; Maire, V.

2015-12-01

Since the 1890s it's been known that the wet tropics harbour plants with exceptionally large leaves. Yet the observed latitudinal gradient of leaf size has never been fully explained: it is still unclear which aspects of climate are most important for understanding geographic trends in leaf size, a trait that varies many thousand-fold among species. The key is the leaf-to-air temperature difference, which depends on the balance of energy inputs (irradiance) and outputs (transpirational cooling, losses to the night sky). Smaller leaves track air temperatures more closely than larger leaves. Widely cited optimality-based theories predict an advantage for smaller leaves in dry environments, where transpiration is restricted, but are silent on the latitudinal gradient. We aimed to characterize and explain the worldwide pattern of leaf size. Across 7900 species from 651 sites, here we show that: large-leaved species predominate in wet, hot, sunny environments; smaller-leaved species typify hot, sunny environments only when arid; small leaves are required to avoid freezing in high latitudes and at high elevation, and to avoid overheating in dry environments. This simple pattern was unclear in earlier, more limited analyses. We present a simple but robust, fresh approach to energy-balance modelling for both day-time and night-time leaf-to-air temperature differences, and thus risk of overheating and of frost damage. Our analysis shows night-chilling is important as well as day-heating, and simplifies leaf temperature modelling. It provides both a framework for modelling leaf size constraints, and a solution to one of the oldest conundrums in ecology. Although the path forward is not yet fully clear, because of its role in controlling leaf temperatures we suggest that climate-related leaf size constraints could usefully feature in the next generation of land ecosystem models.
BREEDING AND GENETICS SYMPOSIUM: Resilience and lessons from studies in genetics of heat stress.

PubMed

Misztal, I

2017-04-01

Production environments are expected to change, mostly to a hotter climate but also possibly more extreme and drier. Can the current generation of farm animals cope with the changes or should it be specifically selected for changing conditions? In general, genetic selection produces animals with a smaller environmental footprint but also with smaller environmental flexibility. Some answers are coming from heat-stress research across species, with heat tolerance partly understood as a greater environmental flexibility. Specific studies in various species show the complexities of defining and selecting for heat tolerance. In Holsteins, the genetic component for effect of heat stress on production approximately doubles in second and quadruples in third parity. Cows with elevated body temperature have the greatest production under heat stress but probably are at risk for increased mortality. In hot but less intensive environments, the effect of heat stress on production is minimal, although the negative effect on fertility remains. Mortality peaks under heat stress and increases with parity. In Angus, the effect of heat stress is stronger only in selected regions, probably because of adaptation of calving seasons to local conditions and crossbreeding. Genetically, the direct effect shows variability because of heat stress, but the maternal effect does not, probably because dams shield calves from environmental challenges. In pigs, the effect of heat stress is strong for commercial farms but almost nothing for nucleus farms, which have lower pig density and better heat abatement. Under intensive management, heat stress is less evident in drier environments because of more efficient cooling. A genetic component of heat stress exists, but it is partly masked by improving management and selection based on data from elite farms. Genetic selection may provide superior identification of heat-tolerant animals, but a few cycles may be needed for clear results. Also, simple traits exist that are strongly related to heat stress (e.g., slick hair in dairy cattle and shedding intensity in Angus). Defining resilience may be difficult, especially when masked by improving environment. Under climate change, the current selection strategies may be adequate if they 1) are accompanied by constantly improving management, 2) use commercial data, and 3) include traits important under climate change (e.g., mortality).
The hybrid personal cooling system (PCS) could effectively reduce the heat strain while exercising in a hot and moderate humid environment.

PubMed

Song, Wenfang; Wang, Faming

2016-08-01

This study aimed to examine the effectiveness of a hybrid personal cooling system (PCS) in mitigating body heat stain while exercising in a hot environment. Eight subjects underwent two trials: PCS and CON (i.e. no cooling). All trials were conducted at an air temperature of 36 ± 0.5 °C and RH = 59 ± 5%. The key findings demonstrated that the PCS could significantly reduce the core temperature, mean skin temperature, heart rate and physiological strain index during both exercise and recovery periods (p < 0.05). Subjective perceptions were also significantly alleviated in PCS at the end of the exercise and during the recovery (p < 0.05). Besides, the PCS could also bring remarkable benefits in lowering local skin temperatures and in improving perceptual sensations in both upper and lower body during both exercise and recovery periods (p < 0.05). It was thus concluded that the hybrid PCS is effective in mitigating body heat strain while exercising in a hot environment. Practitioner Summary: In hot and humid environments, body heat dissipation through sweating is greatly restricted. Our newly developed hybrid PCS could effectively alleviate heat strain while exercising in hot environments. The findings contribute to the body of knowledge in improving the health and well-being of sportsmen while exercising in hot environments.
The response of streambed nitrogen cycling to spatial and temporal hyporheic vertical flux patterns and associated residence times

NASA Astrophysics Data System (ADS)

Briggs, M. A.; Lautz, L. K.; Hare, D. K.

2011-12-01

Small beaver dams enhance the development of patchy micro-environments along the stream corridor by trapping sediment and creating complex streambed morphologies. This generates intricate hyporheic flux patterns that govern the exchange of oxygen and redox sensitive solutes between the water column and the streambed, and exert control on the biogeochemical cycling of nitrogen. Specifically, flowpaths from the stream into the subsurface with low residence times create oxic conditions that favor nitrification, while flowpaths with longer residence times become anoxic and favor denitrification. To investigate these processes we collected vertical profiles of pore water upstream of two beaver dams in Wyoming, USA at nine locations with varied morphology. We sampled pore water to the 0.55 m depth every week for five weeks as stream discharge dropped by 45% and subsequently measured concentrations of dissolved oxygen and several redox sensitive solutes, including nitrate. Additionally, estimates of hyporheic flux along these nine vertical profiles through time were made using high-resolution heat data combined with 1-D heat transport modeling. The data show that areas of rapid, deep hyporheic flux at the glides immediately upstream of the dams were oxygen rich, and were generally sites of moderate net nitrification to at least the 0.35 m depth. These conditions were relatively steady over the study period. Hyporheic zones at sediment bars closest to the dams were hotspots of nitrate production to a depth of 0.35 m, with nitrate concentrations increasing by as much as 400% as vertical flux fell sharply and residence times increased over the study period. In contrast, shallow bars farther upstream from the dams showed increasing fluxes and decreased residence times, which caused a shift from net denitrification to net nitrification over the period at shallow depths. These results support previous work indicating threshold behavior of nitrogen cycling in response to flowpath residence time. Furthermore the threshold between oxic and anoxic conditions, and subsequently the zone of peak net nitrification, can be approached from either end of the redox spectrum simultaneously within the same system in response to complex temporal changes in vertical flux. Finally, pools were sites of weak hyporheic flux, overall anoxic conditions and net denitrification. These patterns offer more evidence of the complicated spatial and temporal patterns of nitrogen cycling in the hyporheic zone, but also show that flux patterns measured with 1-D heat transport models may be used to develop predictive relationships regarding streambed biogeochemical conditions and hot spots of nitrogen cycling.
Map of Io Volcanic Heat Flow

NASA Image and Video Library

2015-09-15

This frame from an animation shows Jupiter volcanic moon Io as seen by NASA Voyager and Galileo spacecraft (at left) and the pattern of heat flow from 242 active volcanoes (at right). The red and yellow areas are places where local heat flow is greatest -- the result of magma erupting from Io's molten interior onto the surface. The map is the result of analyzing decades of observations from spacecraft and ground-based telescopes. It shows Io's usual volcanic thermal emission, excluding the occasional massive but transient "outburst" eruption; in other words, this is what Io looks like most of the time. This heat flow map will be used to test models of interior heating. The map shows that areas of enhanced volcanic heat flow are not necessarily correlated with the number of volcanoes in a particular region and are poorly correlated with expected patterns of heat flow from current models of tidal heating -- something that is yet to be explained. This research is published in association with a 2015 paper in the journal Icarus by A. Davies et al., titled "Map of Io's Volcanic Heat Flow," (http://dx.doi.org/10.1016/j.icarus.2015.08.003.) http://photojournal.jpl.nasa.gov/catalog/PIA19655
40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 11 2014-07-01 2014-07-01 false What heat exchange systems are exempt... Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What heat exchange systems are exempt from the requirements of this subpart? Your heat exchange system is...
40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 11 2013-07-01 2013-07-01 false What heat exchange systems are exempt... Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What heat exchange systems are exempt from the requirements of this subpart? Your heat exchange system is...
40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 11 2012-07-01 2012-07-01 false What heat exchange systems are exempt... Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What heat exchange systems are exempt from the requirements of this subpart? Your heat exchange system is...
40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 10 2011-07-01 2011-07-01 false What heat exchange systems are exempt... Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What heat exchange systems are exempt from the requirements of this subpart? Your heat exchange system is...
Impact of wall hydrophobicity on condensation flow and heat transfer in silicon microchannels

NASA Astrophysics Data System (ADS)

Fang, Chen; Steinbrenner, Julie E.; Wang, Fu-Min; Goodson, Kenneth E.

2010-04-01

While microchannel condensation has been the subject of several recent studies, the critical impact of wall hydrophobicity on the microchannel condensation flow has received very little attention. The paper experimentally studies steam condensation in a silicon microchannel 286 µm in hydraulic diameter with three different wall hydrophobicities. It is found that the channel surface wettability has a significant impact on the flow pattern, pressure drop and heat transfer characteristic. Spatial flow pattern transition is observed in both hydrophobic and hydrophilic channels. In the hydrophobic channel, the transition from dropwise/slugwise flow to plug flow is induced by the slug instability. In the hydrophilic channel, the flow transition is characterized by the periodic bubble detachment, a process in which pressure evolution is found important. Local temperature measurement is conducted and heat flux distribution in the microchannel is reconstructed. For the same inlet vapor flux and temperature, the hydrophobic microchannel yields higher heat transfer rate and pressure drop compared to the hydrophilic channel. The difference is attributed to the distinction in flow pattern and heat transfer mechanism dictated by the channel hydrophobicity. This study highlights the importance of the channel hydrophobicity control for the optimization of the microchannel condenser.
Patterning of alloy precipitation through external pressure

NASA Astrophysics Data System (ADS)

Franklin, Jack A.

Due to the nature of their microstructure, alloyed components have the benefit of meeting specific design goals across a wide range of electrical, thermal, and mechanical properties. In general by selecting the correct alloy system and applying a proper heat treatment it is possible to create a metallic sample whose properties achieve a unique set of design requirements. This dissertation presents an innovative processing technique intended to control both the location of formation and the growth rates of precipitates within metallic alloys in order to create multiple patterned areas of unique microstructure within a single sample. Specific experimental results for the Al-Cu alloy system will be shown. The control over precipitation is achieved by altering the conventional heat treatment process with an external surface load applied to selected locations during the quench and anneal. It is shown that the applied pressures affect both the rate and directionality of the atomic diffusion in regions close to the loaded surfaces. The control over growth rates is achieved by altering the enthalpic energy required for successful diffusion between lattice sites. Changes in the local chemical free energy required to direct the diffusion of atoms are established by introducing a non-uniform elastic strain energy field within the samples created by the patterned surface pressures. Either diffusion rates or atomic mobility can be selected as the dominating control process by varying the quench rate; with slower quenches having greater control over the mobility of the alloying elements. Results have shown control of Al2Cu precipitation over 100 microns on mechanically polished surfaces. Further experimental considerations presented will address consistency across sample ensembles. This includes repeatable pressure loading conditions and the chemical interaction between any furnace environments and both the alloy sample and metallic pressure loading devices.
Towards More Comprehensive Projections of Urban Heat-Related Mortality: Estimates for New York City under Multiple Population, Adaptation, and Climate Scenarios

PubMed Central

Petkova, Elisaveta P.; Vink, Jan K.; Horton, Radley M.; Gasparrini, Antonio; Bader, Daniel A.; Francis, Joe D.; Kinney, Patrick L.

2016-01-01

Background: High temperatures have substantial impacts on mortality and, with growing concerns about climate change, numerous studies have developed projections of future heat-related deaths around the world. Projections of temperature-related mortality are often limited by insufficient information to formulate hypotheses about population sensitivity to high temperatures and future demographics. Objectives: The present study derived projections of temperature-related mortality in New York City by taking into account future patterns of adaptation or demographic change, both of which can have profound influences on future health burdens. Methods: We adopted a novel approach to modeling heat adaptation by incorporating an analysis of the observed population response to heat in New York City over the course of eight decades. This approach projected heat-related mortality until the end of the 21st century based on observed trends in adaptation over a substantial portion of the 20th century. In addition, we incorporated a range of new scenarios for population change until the end of the 21st century. We then estimated future heat-related deaths in New York City by combining the changing temperature–mortality relationship and population scenarios with downscaled temperature projections from the 33 global climate models (GCMs) and two Representative Concentration Pathways (RCPs). Results: The median number of projected annual heat-related deaths across the 33 GCMs varied greatly by RCP and adaptation and population change scenario, ranging from 167 to 3,331 in the 2080s compared with 638 heat-related deaths annually between 2000 and 2006. Conclusions: These findings provide a more complete picture of the range of potential future heat-related mortality risks across the 21st century in New York City, and they highlight the importance of both demographic change and adaptation responses in modifying future risks. Citation: Petkova EP, Vink JK, Horton RM, Gasparrini A, Bader DA, Francis JD, Kinney PL. 2017. Towards more comprehensive projections of urban heat-related mortality: estimates for New York City under multiple population, adaptation, and climate scenarios. Environ Health Perspect 125:47–55; http://dx.doi.org/10.1289/EHP166 PMID:27337737
Towards More Comprehensive Projections of Urban Heat-Related Mortality: Estimates for New York City under Multiple Population, Adaptation, and Climate Scenarios.

PubMed

Petkova, Elisaveta P; Vink, Jan K; Horton, Radley M; Gasparrini, Antonio; Bader, Daniel A; Francis, Joe D; Kinney, Patrick L

2017-01-01

High temperatures have substantial impacts on mortality and, with growing concerns about climate change, numerous studies have developed projections of future heat-related deaths around the world. Projections of temperature-related mortality are often limited by insufficient information to formulate hypotheses about population sensitivity to high temperatures and future demographics. The present study derived projections of temperature-related mortality in New York City by taking into account future patterns of adaptation or demographic change, both of which can have profound influences on future health burdens. We adopted a novel approach to modeling heat adaptation by incorporating an analysis of the observed population response to heat in New York City over the course of eight decades. This approach projected heat-related mortality until the end of the 21st century based on observed trends in adaptation over a substantial portion of the 20th century. In addition, we incorporated a range of new scenarios for population change until the end of the 21st century. We then estimated future heat-related deaths in New York City by combining the changing temperature-mortality relationship and population scenarios with downscaled temperature projections from the 33 global climate models (GCMs) and two Representative Concentration Pathways (RCPs). The median number of projected annual heat-related deaths across the 33 GCMs varied greatly by RCP and adaptation and population change scenario, ranging from 167 to 3,331 in the 2080s compared with 638 heat-related deaths annually between 2000 and 2006. These findings provide a more complete picture of the range of potential future heat-related mortality risks across the 21st century in New York City, and they highlight the importance of both demographic change and adaptation responses in modifying future risks. Citation: Petkova EP, Vink JK, Horton RM, Gasparrini A, Bader DA, Francis JD, Kinney PL. 2017. Towards more comprehensive projections of urban heat-related mortality: estimates for New York City under multiple population, adaptation, and climate scenarios. Environ Health Perspect 125:47-55; http://dx.doi.org/10.1289/EHP166.
Physiological Responses to Overdressing and Exercise-Heat Stress in Trained Runners.

PubMed

Ely, Brett R; Blanchard, Laurie A; Steele, Jared R; Francisco, Michael A; Cheuvront, Samuel N; Minson, Christopher T

2018-06-01

Heat acclimation is the best strategy to improve performance in a hot environment. Many athletes seeking the benefits of heat acclimation lack access to a hot environment for exercise and, thus, rely on overdressing to simulate environmental heat stress. It is currently unknown whether this approach produces the requisite thermoregulatory strain necessary for heat acclimation in trained men and women. To compare physiological and cellular responses to exercise in a hot environment (HOT; 40°C, 30% RH) with minimal clothing (clo = 0.87) and in a temperate environment (CLO; 15°C, 50% RH) with overdressing (clo = 1.89) in both men and women. HR, rectal temperature (Tre), mean skin temperature (Tsk), sweating rate (SR), and extracellular heat shock protein (eHSP)72 were measured in 13 (7 males, 6 females) well-trained runners (V˙O2max: 58.7 ± 10.7 mL·kg·min) in response to ~60 min of treadmill running at 50%-60% V˙O2max in HOT and CLO. Tre increased in both conditions, but the increase was greater in HOT (ΔTre HOT: 2.6°C ± 0.1°C; CLO 2.0°C ± 0.1°C; P = 0.0003). SR was also higher in HOT (1.41 ± 0.1 L h; CLO: 1.16 ± 0.1 L·h; P = 0.0001). eHSP72 increased in HOT (% change: 59% ± 11%; P = 0.03) but not in CLO (6% ± 2%; P = 0.31). Mean Tsk and HR were not different between HOT and CLO in men but were higher in HOT for women. These data support the idea that overdressing during exercise in a temperate environment may produce the high Tre, Tsk, HR, and SR necessary for adaptation, but these responses do not match those in hot, dry environments. It is possible that greater exercise stimulus, warmer environment, or more clothing may be required to allow for a similar level of acclimation.
The effect of near-surface heating on the underlying convection pattern with application to Enceladus

NASA Astrophysics Data System (ADS)

Roberts, J. H.; Nimmo, F.

2007-12-01

Rapid strike-slip motion is predicted to be a consequence of diurnal tidal stresses in most satellites of the outer solar system with short orbital timescales [1]. Such motion can lead to near-surface heating through friction or viscous dissipation [2]. Here we discuss the effect of near-surface shear heating on convection in the underlying ice shells of icy satellites [3], with a focus on Enceladus and a possible origin of the south polar thermal anomaly [4]. We present models of convection in spherical ice shells including both spatially variable volumetric tidal heating [5] and regional shear heating localized in the top 5 km at either the pole or the equator. We observe that the presence of the near-surface heating strongly controls the convective pattern, increasing the wavelength, and promoting the formation of a hot upwelling beneath the shear zone. Our results suggest that localized near- surface heating may result in a degree-1 convective planform in an ice shell of a thickness that may be appropriate for a differentiated Enceladus (d < 0.36 Rsat). The near-surface heating and convection pattern will produce a localized heat flow anomaly. The upwelling beneath the shear zone also produces a few hundred meters of long-wavelength dynamic topography. The ℓ=2 component of the topography may cause reorientation of the satellite [6]. [1] Hoppa, G., B. R. Tufts, R. Greenberg, and P. Geissler, Icarus, 141, 287-298, 1999. [2] Nimmo, F., E. Gaidos, JGR, 107, 5021, 2002. [3] Han, L., A. P. Showman, LPSC XXXVIII, #2277, 2007. [4] Spencer, J. R., et al., Science, 311, 1401-1405. [5] Tobie, G., A. Mocquet, C. Sotin, Icarus, 177 534-549. [6] Nimmo, F., R. T. Pappalardo, Nature, 441, 614-616.
A simplified analytical solution for thermal response of a one-dimensional, steady state transpiration cooling system in radiative and convective environment

NASA Technical Reports Server (NTRS)

Kubota, H.

1976-01-01

A simplified analytical method for calculation of thermal response within a transpiration-cooled porous heat shield material in an intense radiative-convective heating environment is presented. The essential assumptions of the radiative and convective transfer processes in the heat shield matrix are the two-temperature approximation and the specified radiative-convective heatings of the front surface. Sample calculations for porous silica with CO2 injection are presented for some typical parameters of mass injection rate, porosity, and material thickness. The effect of these parameters on the cooling system is discussed.

SEE Observations of Ionospheric Heating from HAARP Using Orbital Angular Momentum

NASA Astrophysics Data System (ADS)

Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.

2013-12-01

High power HF radio waves exciting the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaksa is the world's largest heating facility, providing effective radiated powers in the gigawatt range. Experiments performed at HAARP have allowed researchers to study many non-linear effects of wave-plasma interactions. Stimulated Electromagnetic Emission (SEE) is of interest to the ionospheric community for its diagnostic purposes. Typical SEE experiments at HAARP have focused on characterizing the parametric decay of the electromagnetic pump wave into several different wave modes such as upper and lower hybrid, ion acoustic, ion-Bernstein and electron-Bernstein. These production modes have been extensively studied at HAARP using traditional beam heating patterns and SEE detection. New results are present from HAARP experiments using an excitation mode that attempts to impart orbital angular momentum (OAM) into the heating region. This OAM mode is also referred to as a 'twisted beam.' Previous analysis of twisted beam heating shows that the SEE results obtained are nearly identical to the modes without OAM. Recent twisted beam heating experiments have produced SEE modes not previously characterized. These new modes are presented and discussed. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional 'solid spot' region. The ring heating pattern may be more conducive to the creation of artificial ionization clouds. The results of these runs include artificial ionization creation and evolution as pertaining to the twisted beam pattern.
Turning Passive Brownian Motion Into Active Motion

NASA Astrophysics Data System (ADS)

Sevilla, Francisco J.; VáSquez-Arzola, Alejandro; Puga-Cital, Enrique

We consider out-of-equilibrium phenomena, specifically, the pattern of motion of active particles. These particles absorb energy from the environment and transform it into self-locomotion, generally, through complex mechanisms. Though the out-of-equilibrium nature of on the motion of these systems is well recognized, is generally difficult to pinpoint how far from equilibrium these systems are. In this work we elucidate the out-of-equilibrium nature of non-interacting, trapped, active particles, whose pattern of motion is described by a run-and-tumble dynamics. We show that the stationary distributions of these run-and-tumble particles, moving under the effects of an external potential, is equivalent to the stationary distribution of non-interacting, passive Brownian particles moving in the same potential but in an inhomogeneous source of heat. The interest in this topic has recently regrown due to the experimental possibility to design man-made active particles that emulate the ones that exist in the biological realm. F.J.S kindly acknowledges support from Grant UNAM-DGAPA-PAPIIT-IN113114.
Low gravity quenching of hot tubes with cryogens

NASA Technical Reports Server (NTRS)

Antar, Basil N.; Collins, Frank G.; Kawaji, M.

1992-01-01

An experimental proceedure for examining flow boiling in low gravity environment is presented. The proceedure involves both ground based and KC-135 flight experiments. Two experimental apparati were employed, one for studying subcooled liquid boiling and another for examining saturated liquid boiling. For the saturated flow experiments, liquid nitrogen was used while freon 113 was used for the subcooled flow experiments. The boiling phenomenon was investigated in both cases using flow visualization techniques as well as tube wall temperature measurements. The flow field in both cases was established by injecting cold liquid in a heated tube whose temperature was set above the saturation values. The tubes were both vertically and horizontally supported with the liquid injected from the lower end of the tube. The results indicate substantial differences in the flow patterns established during boiling between the ground based, (1-g), experiments and the flight experiments, (low-g). These differences in the flow patterns will be discussed and some explanations will be offered.
40 CFR 91.415 - Raw gaseous sampling procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw gaseous sampling procedures. 91.415 Section 91.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Raw gaseous sampling procedures. Fit all heated sampling lines with a heated filter to extract solid...
40 CFR 91.415 - Raw gaseous sampling procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Raw gaseous sampling procedures. 91.415 Section 91.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Raw gaseous sampling procedures. Fit all heated sampling lines with a heated filter to extract solid...
40 CFR 90.415 - Raw gaseous sampling procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw gaseous sampling procedures. 90.415 Section 90.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Test Procedures § 90.415 Raw gaseous sampling procedures. Fit all heated sampling lines with a heated...
40 CFR 90.415 - Raw gaseous sampling procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Raw gaseous sampling procedures. 90.415 Section 90.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Test Procedures § 90.415 Raw gaseous sampling procedures. Fit all heated sampling lines with a heated...
Chapter 5: Thermal Indices and Their Applications for Livestock Environments

USDA-ARS?s Scientific Manuscript database

Heat exchanges with the environment are a crucial process for maintaining homeothermy by humans and other animals. These exchanges involve heat production, conservation and dissipation, and are dependent on both biological and physical factors. The complexity of these exchanges has led to many attem...
SRB thermal protection systems materials test results in an arc-heated nitrogen environment

NASA Technical Reports Server (NTRS)

Wojciechowski, C. J.

1979-01-01

The external surface of the Solid Rocket Booster (SRB) will experience imposed thermal and shear environments due to aerodynamic heating and radiation heating during launch, staging and reentry. This report is concerned with the performance of the various TPS materials during the staging maneuver. During staging, the wash from the Space Shuttle Main Engine (SSME) exhust plumes impose severe, short duration, thermal environments on the SRB. Five different SRB TPS materials were tested in the 1 MW Arc Plasma Generator (APG) facility. The maximum simulated heating rate obtained in the APG facility was 248 Btu/sq ft./sec, however, the test duration was such that the total heat was more than simulated. Similarly, some local high shear stress levels of 0.04 psia were not simulated. Most of the SSME plume impingement area on the SRB experiences shear stress levels of 0.02 psia and lower. The shear stress levels on the test specimens were between 0.021 and 0.008 psia. The SSME plume stagnation conditions were also simulated.
Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2008-01-01

Spacecraft radiators are sized for their maximum heat load in their warmest thermal environment, but must operate at reduced heat loads and in colder environments. For systems where the radiator environment can be colder than the working fluid freezing temperature, radiator freezing becomes an issue. Radiator freezing has not been a major issue for the Space Shuttle and the International Space Station (ISS) active thermal control systems (ATCSs) because they operate in environments that are warm relative to the freezing point of their external coolants (Freon-21 and ammonia, respectively). For a vehicle that lands at the Lunar South Pole, the design thermal environment is 215K, but the radiator working fluid must also be kept from freezing during the 0 K sink of transit. A radiator bypass flow control design such as those used on the Space Shuttle and ISS requires more than 30% of the design heat load to avoid radiator freezing during transit - even with a very low freezing point working fluid. By changing the traditional ATCS architecture to include a regenerating heat exchanger inboard of the radiator and by using a regenerator bypass flow control valve to maintain system setpoint, the required minimum heat load can be reduced by more than half. This gives the spacecraft much more flexibility in design and operation. The present work describes the regenerator bypass ATCS setpoint control methodology. It includes analytical results comparing the performance of this system to the traditional radiator bypass system. Finally, a summary of the advantages of the regenerator bypass system are presented.
The Galapagos Spreading Centre at 86o W: a detailed geothermal field study.

USGS Publications Warehouse

Green, K.E.; Von Herzen, R. P.; Williams, D.L.

1981-01-01

We report here measurements of the heat flow field of the Galapagos Spreading Center on crust of age less than 1.0 m.y. The 443 measurements in an area of about 570 km2 reveal the general planform of the geothermal flux and permit the first truly areal estimate of the near-axis conductive heat flux. The intrusion process and associated hydrothermal circulation dominate the surface heat flow pattern, with circulation apparently continuing beyong the limits of our survey. The areal average of the conductive heat flux is 7.1+-0.8 HFU (295+-33 m W/m2), about one-third the heat flux predicted by plate models. The remaining heat is apparently removed by venting of hydrothermal waters at the spreading axis and through basalt outcrops and hydrothermal mounds off axis. The pattern of surface heat flux is lineated parallel to the axis and the strongly lineated topography. Sharp lateral gradients in the heat flow, greater than 10 HFU/km near escarpments and commonly expressed as high heat flow at the tops of the scarps and lower heat flow in the valleys, may indicate a local concentration of the circulation by surface fault systems and/or variable sediment thickness. -Authors
Numerical study of heat transfer characteristics in BOG heat exchanger

NASA Astrophysics Data System (ADS)

Yan, Yan; Pfotenhauer, John M.; Miller, Franklin; Ni, Zhonghua; Zhi, Xiaoqin

2016-12-01

In this study, a numerical study of turbulent flow and the heat transfer process in a boil-off liquefied natural gas (BOG) heat exchanger was performed. Finite volume computational fluid dynamics and the k - ω based shear stress transport model were applied to simulate thermal flow of BOG and ethylene glycol in a full-sized 3D tubular heat exchanger. The simulation model has been validated and compared with the engineering specification data from its supplier. In order to investigate thermal characteristics of the heat exchanger, velocity, temperature, heat flux and thermal response were studied under different mass flowrates in the shell-side. The shell-side flow pattern is mostly determined by viscous forces, which lead to a small velocity and low temperature buffer area in the bottom-right corner of the heat exchanger. Changing the shell-side mass flowrate could result in different distributions of the shell-side flow. However, the distribution in the BOG will remain in a relatively stable pattern. Heat flux increases along with the shell-side mass flowrate, but the increase is not linear. The ratio of increased heat flux to the mass flow interval is superior at lower mass flow conditions, and the threshold mass flow for stable working conditions is defined as greater than 0.41 kg/s.
Heat transfer in a one-dimensional harmonic crystal in a viscous environment subjected to an external heat supply

NASA Astrophysics Data System (ADS)

Gavrilov, S. N.; Krivtsov, A. M.; Tsvetkov, D. V.

2018-05-01

We consider unsteady heat transfer in a one-dimensional harmonic crystal surrounded by a viscous environment and subjected to an external heat supply. The basic equations for the crystal particles are stated in the form of a system of stochastic differential equations. We perform a continualization procedure and derive an infinite set of linear partial differential equations for covariance variables. An exact analytic solution describing unsteady ballistic heat transfer in the crystal is obtained. It is shown that the stationary spatial profile of the kinetic temperature caused by a point source of heat supply of constant intensity is described by the Macdonald function of zero order. A comparison with the results obtained in the framework of the classical heat equation is presented. We expect that the results obtained in the paper can be verified by experiments with laser excitation of low-dimensional nanostructures.
Compact acoustic refrigerator

DOEpatents

Bennett, Gloria A.

1992-01-01

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.
Improved heat dissipation in gallium nitride light-emitting diodes with embedded graphene oxide pattern.

PubMed

Han, Nam; Cuong, Tran Viet; Han, Min; Ryu, Beo Deul; Chandramohan, S; Park, Jong Bae; Kang, Ji Hye; Park, Young-Jae; Ko, Kang Bok; Kim, Hee Yun; Kim, Hyun Kyu; Ryu, Jae Hyoung; Katharria, Y S; Choi, Chel-Jong; Hong, Chang-Hee

2013-01-01

The future of solid-state lighting relies on how the performance parameters will be improved further for developing high-brightness light-emitting diodes. Eventually, heat removal is becoming a crucial issue because the requirement of high brightness necessitates high-operating current densities that would trigger more joule heating. Here we demonstrate that the embedded graphene oxide in a gallium nitride light-emitting diode alleviates the self-heating issues by virtue of its heat-spreading ability and reducing the thermal boundary resistance. The fabrication process involves the generation of scalable graphene oxide microscale patterns on a sapphire substrate, followed by its thermal reduction and epitaxial lateral overgrowth of gallium nitride in a metal-organic chemical vapour deposition system under one-step process. The device with embedded graphene oxide outperforms its conventional counterpart by emitting bright light with relatively low-junction temperature and thermal resistance. This facile strategy may enable integration of large-scale graphene into practical devices for effective heat removal.
Condensation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low mass fluxes

NASA Astrophysics Data System (ADS)

Kim, Nae-Hyun

2016-12-01

R-410A condensation heat transfer and pressure drop data are provided for a 7.0 mm O.D. microfin tube at low mass fluxes (50-250 kg/m2 s). The heat transfer coefficient of the microfin tube shows a minimum behavior with the mass flux. At a low mass flux, where flow pattern is stratified, condensation induced by surface tension by microfins overwhelms condensation induced by shear, and the heat transfer coefficient decreases as mass flux increases. At a high mass flux, where flow pattern is annular, condensation induced by shear governs the heat transfer, and the heat transfer coefficient increases as mass flux increases. The pressure drop of the microfin tube is larger than that of the smooth tube at the annular flow regime. On the contrary, the pressure drop of the smooth tube is larger than that of the microfin tube at the stratified flow regime.
Innovative Multi-Environment, Multimode Thermal Control System

NASA Technical Reports Server (NTRS)

Singh, Bhim S.; Hasan, Mohammad H.

2007-01-01

Innovative multi-environment multimode thermal management architecture has been described that is capable of meeting widely varying thermal control requirements of various exploration mission scenarios currently under consideration. The proposed system is capable of operating in a single-phase or two-phase mode rejecting heat to the colder environment, operating in a two-phase mode with heat pump for rejecting heat to a warm environment, as well as using evaporative phasechange cooling for the mission phases where the radiator is incapable of rejecting the required heat. A single fluid loop can be used internal and external to the spacecraft for the acquisition, transport and rejection of heat by the selection of a working fluid that meets NASA safety requirements. Such a system may not be optimal for each individual mode of operation but its ability to function in multiple modes may permit global optimization of the thermal control system. The architecture also allows flexibility in partitioning of components between the various Constellation modules to take advantage of operational requirements in various modes consistent with the mission needs. Preliminary design calculations using R-134 as working fluid show the concept to be feasible to meet the heat rejection requirements that are representative of the Crew Exploration Vehicle and Lunar Access Module for nominal cases. More detailed analyses to establish performance under various modes and environmental conditions are underway.
Towards a Better Understanding of Water Stores and Fluxes: Model Observation Synthesis in a Snowmelt Dominated Research Watershed

NASA Astrophysics Data System (ADS)

Ryken, A.; Gochis, D.; Carroll, R. W. H.; Bearup, L. A.; Williams, K. H.; Maxwell, R. M.

2017-12-01

The hydrology of high-elevation, mountainous regions is poorly represented in Earth Systems Models (ESMs). In addition to regulating downstream water delivery, these ecosystems play an important role in the storage and land-atmosphere exchange of carbon and water. Water balances are sensitive to the amount of water stored in the snowpack (SWE) and the amount of water leaving the system in the form of evapotranspiration—two pieces of the hydrologic cycle that are difficult to observe and model in heterogeneous mountainous regions due to spatially variant weather patterns. In an effort to resolve this hydrologic gap in ESMs, this study seeks to better understand the interactions between groundwater, carbon flux, and the lower atmosphere in these high-altitude environments through integration of field observations and model simulations. We compare model simulations to field observations to elucidate process performance combined with a sensitivity analysis to better understand parameter uncertainty. Observations from a meteorological station in the East River Basin are used to force an integrated single-column hydrologic model, ParFlow-CLM. This met station is co-located with an eddy covariance tower, which, along with snow surveys, is used to better constrain the water, carbon, and energy fluxes in the coupled land-atmosphere model to increase our understanding of high-altitude headwaters. Preliminary results suggest the model compares well to the eddy covariance tower and field observations, shown through both correct magnitude and timing of peak SWE along with similar magnitudes and diurnal patterns of heat and water fluxes. Initial sensitivity analysis results show that an increase in temperature leads to a decrease in peak SWE as well as an increase in latent heat revealing a sensitivity of the model to air temperature. Further sensitivity analysis will help us understand more parameter uncertainty. Through obtaining more accurate and higher resolution meteorological data and applying it to a coupled hydrologic model, this study can lead to better representation of mountainous environments in all ESMs.
The thermoregulatory function of the human hand: How do palm and digit proportions affect heat loss?

PubMed

Payne, Stephanie; Macintosh, Alison; Stock, Jay

2018-03-30

The current study assessed whether ecogeographical patterns seen in hand proportions correlate with heat loss directly. Using a brief severe cold immersion experiment on the hand, the influence of hand and digit dimensions on heat loss was evaluated. A sample of 113 living individuals were tested. Two-dimensional and three-dimensional scanning techniques were used to assess hand and digit dimensions. Thermal imaging analysis was used to quantify heat loss during a 3-min ice-water immersion of the hands. When body size was accounted for, hand width and digit length relative to total hand length were significant predictors of heat loss from the hand. The current study provides empirical evidence to support the link between thermodynamic principles relating to surface area-to-volume ratio, and ecogeographical patterns associated with temperature. © 2018 Wiley Periodicals, Inc.
The effect of the shape and size of gold seeds irradiated with ultrasound on the bio-heat transfer in tissue.

PubMed

Gkigkitzis, Ioannis; Austerlitz, Carlos; Haranas, Ioannis; Campos, Diana

2015-01-01

The aim of this report is to propose a new methodology to treat prostate cancer with macro-rod-shaped gold seeds irradiated with ultrasound and develop a new computational method for temperature and thermal dose control of hyperthermia therapy induced by the proposed procedure. A computer code representation, based on the bio-heat diffusion equation, was developed to calculate the heat deposition and temperature elevation patterns in a gold rod and in the tissue surrounding it as a result of different therapy durations and ultrasound power simulations. The numerical results computed provide quantitative information on the interaction between high-energy ultrasound, gold seeds and biological tissues and can replicate the pattern observed in experimental studies. The effect of differences in shapes and sizes of gold rod targets irradiated with ultrasound is calculated and the heat enhancement and the bio-heat transfer in tissue are analyzed.

Thermal maturity patterns of Cretaceous and Tertiary rocks, San Juan Basin, Colorado and New Mexico

USGS Publications Warehouse

Law, B.E.

1992-01-01

Horizontal and vertical thermal maturity patterns and time-temperature modeling indicate that the high levels of thermal maturity in the northern part of the basin are due to either: 1) convective heat transfer associated with a deeply buried heat source located directly below the northern part of the basin or 2) the circulation of relatively hot fluids into the basin from a heat source north of the basin located near the San Juan Mountains. Time-temperature and kinetic modeling of nonlinear Rm profiles indicates that present-day heat flow is insufficient to account for the measured levels of thermal maturity. Furthermore, in order to match nonlinear Rm profiles, it is necessary to assign artifically high thermal-conductivity values to some of the stratigraphic units. These unrealistically high thermal conductivities are interpreted as evidence of convective heat transfer. -from Author
Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

DOEpatents

Pechersky, M.J.

1999-07-06

An improved method for measuring residual stress in a material is disclosed comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress. 3 figs.
Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

DOEpatents

Pechersky, Martin J.

1999-01-01

An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.
Flow and Pollutant Transport in Urban Street Canyons of Different Aspect Ratios with Ground Heating: Large-Eddy Simulation

NASA Astrophysics Data System (ADS)

Li, Xian-Xiang; Britter, Rex E.; Norford, Leslie K.; Koh, Tieh-Yong; Entekhabi, Dara

2012-02-01

A validated large-eddy simulation model was employed to study the effect of the aspect ratio and ground heating on the flow and pollutant dispersion in urban street canyons. Three ground-heating intensities (neutral, weak and strong) were imposed in street canyons of aspect ratio 1, 2, and 0.5. The detailed patterns of flow, turbulence, temperature and pollutant transport were analyzed and compared. Significant changes of flow and scalar patterns were caused by ground heating in the street canyon of aspect ratio 2 and 0.5, while only the street canyon of aspect ratio 0.5 showed a change in flow regime (from wake interference flow to skimming flow). The street canyon of aspect ratio 1 does not show any significant change in the flow field. Ground heating generated strong mixing of heat and pollutant; the normalized temperature inside street canyons was approximately spatially uniform and somewhat insensitive to the aspect ratio and heating intensity. This study helps elucidate the combined effects of urban geometry and thermal stratification on the urban canyon flow and pollutant dispersion.
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

Code of Federal Regulations, 2013 CFR

2013-07-01

... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

Code of Federal Regulations, 2012 CFR

2012-07-01

... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

Code of Federal Regulations, 2014 CFR

2014-07-01

... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

Code of Federal Regulations, 2010 CFR

2010-07-01

... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

Code of Federal Regulations, 2011 CFR

2011-07-01

... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
Determination of clothing evaporative resistance on a sweating thermal manikin in an isothermal condition: heat loss method or mass loss method?

PubMed

Wang, Faming; Gao, Chuansi; Kuklane, Kalev; Holmér, Ingvar

2011-08-01

This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing evaporative resistance conducted in an isothermal condition (T(manikin) = T(a) = T(r)). Five vocational clothing ensembles with a thermal insulation range of 1.05-2.58 clo were selected and measured on a sweating thermal manikin 'Tore'. The reasons why the isothermal heat loss method generates a higher evaporative resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of evaporative heat energy taken from the environment. It was found that clothing evaporative resistance values by the heat loss option were 11.2-37.1% greater than those based on the mass loss option. The percentage of evaporative heat loss taken from the environment (H(e,env)) for all test scenarios ranged from 10.9 to 23.8%. The real evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing evaporative resistance, it is suggested that manikin measurements on the determination of clothing evaporative resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing evaporative resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use.
Evolution of solidification texture during additive manufacturing

PubMed Central

Wei, H. L.; Mazumder, J.; DebRoy, T.

2015-01-01

Striking differences in the solidification textures of a nickel based alloy owing to changes in laser scanning pattern during additive manufacturing are examined based on theory and experimental data. Understanding and controlling texture are important because it affects mechanical and chemical properties. Solidification texture depends on the local heat flow directions and competitive grain growth in one of the six <100> preferred growth directions in face centered cubic alloys. Therefore, the heat flow directions are examined for various laser beam scanning patterns based on numerical modeling of heat transfer and fluid flow in three dimensions. Here we show that numerical modeling can not only provide a deeper understanding of the solidification growth patterns during the additive manufacturing, it also serves as a basis for customizing solidification textures which are important for properties and performance of components. PMID:26553246
Evolution of solidification texture during additive manufacturing

DOE PAGES

Wei, H. L.; Mazumder, J.; DebRoy, T.

2015-11-10

Striking differences in the solidification textures of a nickel based alloy owing to changes in laser scanning pattern during additive manufacturing are examined based on theory and experimental data. Understanding and controlling texture are important because it affects mechanical and chemical properties. Solidification texture depends on the local heat flow directions and competitive grain growth in one of the six <100> preferred growth directions in face centered cubic alloys. Furthermore, the heat flow directions are examined for various laser beam scanning patterns based on numerical modeling of heat transfer and fluid flow in three dimensions. Here we show that numericalmore » modeling can not only provide a deeper understanding of the solidification growth patterns during the additive manufacturing, it also serves as a basis for customizing solidification textures which are important for properties and performance of components.« less
Profitable Dairy Cow Traits for Hot Climatic Conditions

USDA-ARS?s Scientific Manuscript database

Permanent differences in environment have led to the distinct cattle races. Bos indicus cattle evolved in the tropical areas of southern Asia, and are heat-tolerant. The major dairy breeds in the USA are Bos taurus cattle, which evolved in temperate environments, that are less heat tolerant but whic...
Potential of a New Lunar Surface Radiator Concept for Hot Lunar Thermal Environments

NASA Technical Reports Server (NTRS)

Ochoa, Dustin A.; Vogel, Matthew R.; Trevino, Luis A.; Stephan, Ryan A.

2008-01-01

The optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft s vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approx.325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Upright Lunar Terrain Radiator Assembly (ULTRA), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of the ULTRA is the absence of louvers or other moving parts and its simple geometry. Analysis of the ULTRA for a lunar extravehicular activity (EVA) portable life support system (PLSS) is shown to provide moderate heat rejection, on average, at all solar incident angles assuming an average radiator temperature of 294 K, whereas prior concepts exhibited insignificant heat rejection or heat absorption at higher incident angles. The performance of the ULTRA for a lunar lander is also discussed and compared to the performance of a vertically oriented, flat panel radiator at various lunar latitudes.
Realtime control of multiple-focus phased array heating patterns based on noninvasive ultrasound thermography.

PubMed

Casper, Andrew; Liu, Dalong; Ebbini, Emad S

2012-01-01

A system for the realtime generation and control of multiple-focus ultrasound phased-array heating patterns is presented. The system employs a 1-MHz, 64-element array and driving electronics capable of fine spatial and temporal control of the heating pattern. The driver is integrated with a realtime 2-D temperature imaging system implemented on a commercial scanner. The coordinates of the temperature control points are defined on B-mode guidance images from the scanner, together with the temperature set points and controller parameters. The temperature at each point is controlled by an independent proportional, integral, and derivative controller that determines the focal intensity at that point. Optimal multiple-focus synthesis is applied to generate the desired heating pattern at the control points. The controller dynamically reallocates the power available among the foci from the shared power supply upon reaching the desired temperature at each control point. Furthermore, anti-windup compensation is implemented at each control point to improve the system dynamics. In vitro experiments in tissue-mimicking phantom demonstrate the robustness of the controllers for short (2-5 s) and longer multiple-focus high-intensity focused ultrasound exposures. Thermocouple measurements in the vicinity of the control points confirm the dynamics of the temperature variations obtained through noninvasive feedback. © 2011 IEEE
Determination of bulk properties of tropical cloud clusters from large scale heat and moisture budgets, appendix B

NASA Technical Reports Server (NTRS)

Yanai, M.; Esbensen, S.; Chu, J.

1972-01-01

The bulk properties of tropical cloud clusters, as the vertical mass flux, the excess temperature, and moisture and the liquid water content of the clouds, are determined from a combination of the observed large-scale heat and moisture budgets over an area covering the cloud cluster, and a model of a cumulus ensemble which exchanges mass, heat, vapor and liquid water with the environment through entrainment and detrainment. The method also provides an understanding of how the environmental air is heated and moistened by the cumulus convection. An estimate of the average cloud cluster properties and the heat and moisture balance of the environment, obtained from 1956 Marshall Islands data, is presented.
Intraspecific variation in cellular and biochemical heat response strategies of Mediterranean Xeropicta derbentina [Pulmonata, Hygromiidae].

PubMed

Troschinski, Sandra; Di Lellis, Maddalena A; Sereda, Sergej; Hauffe, Torsten; Wilke, Thomas; Triebskorn, Rita; Köhler, Heinz-R

2014-01-01

Dry and hot environments challenge the survival of terrestrial snails. To minimize overheating and desiccation, physiological and biochemical adaptations are of high importance for these animals. In the present study, seven populations of the Mediterranean land snail species Xeropicta derbentina were sampled from their natural habitat in order to investigate the intraspecific variation of cellular and biochemical mechanisms, which are assigned to contribute to heat resistance. Furthermore, we tested whether genetic parameters are correlated with these physiological heat stress response patterns. Specimens of each population were individually exposed to elevated temperatures (25 to 52°C) for 8 h in the laboratory. After exposure, the health condition of the snails' hepatopancreas was examined by means of qualitative description and semi-quantitative assessment of histopathological effects. In addition, the heat-shock protein 70 level (Hsp70) was determined. Generally, calcium cells of the hepatopancreas were more heat resistant than digestive cells - this phenomenon was associated with elevated Hsp70 levels at 40°C.We observed considerable variation in the snails' heat response strategy: Individuals from three populations invested much energy in producing a highly elevated Hsp70 level, whereas three other populations invested energy in moderate stress protein levels - both strategies were in association with cellular functionality. Furthermore, one population kept cellular condition stable despite a low Hsp70 level until 40°C exposure, whereas prominent cellular reactions were observed above this thermal limit. Genetic diversity (mitochondrial cytochrome c oxidase subunit I gene) within populations was low. Nevertheless, when using genetic indices as explanatory variables in a multivariate regression tree (MRT) analysis, population structure explained mean differences in cellular and biochemical heat stress responses, especially in the group exposed to 40°C. Our study showed that, even in similar habitats within a close range, populations of the same species use different stress response strategies that all rendered survival possible.
Intraspecific Variation in Cellular and Biochemical Heat Response Strategies of Mediterranean Xeropicta derbentina [Pulmonata, Hygromiidae

PubMed Central

Troschinski, Sandra; Di Lellis, Maddalena A.; Sereda, Sergej; Hauffe, Torsten; Wilke, Thomas; Triebskorn, Rita; Köhler, Heinz-R.

2014-01-01

Dry and hot environments challenge the survival of terrestrial snails. To minimize overheating and desiccation, physiological and biochemical adaptations are of high importance for these animals. In the present study, seven populations of the Mediterranean land snail species Xeropicta derbentina were sampled from their natural habitat in order to investigate the intraspecific variation of cellular and biochemical mechanisms, which are assigned to contribute to heat resistance. Furthermore, we tested whether genetic parameters are correlated with these physiological heat stress response patterns. Specimens of each population were individually exposed to elevated temperatures (25 to 52°C) for 8 h in the laboratory. After exposure, the health condition of the snails' hepatopancreas was examined by means of qualitative description and semi-quantitative assessment of histopathological effects. In addition, the heat-shock protein 70 level (Hsp70) was determined. Generally, calcium cells of the hepatopancreas were more heat resistant than digestive cells - this phenomenon was associated with elevated Hsp70 levels at 40°C.We observed considerable variation in the snails' heat response strategy: Individuals from three populations invested much energy in producing a highly elevated Hsp70 level, whereas three other populations invested energy in moderate stress protein levels - both strategies were in association with cellular functionality. Furthermore, one population kept cellular condition stable despite a low Hsp70 level until 40°C exposure, whereas prominent cellular reactions were observed above this thermal limit. Genetic diversity (mitochondrial cytochrome c oxidase subunit I gene) within populations was low. Nevertheless, when using genetic indices as explanatory variables in a multivariate regression tree (MRT) analysis, population structure explained mean differences in cellular and biochemical heat stress responses, especially in the group exposed to 40°C. Our study showed that, even in similar habitats within a close range, populations of the same species use different stress response strategies that all rendered survival possible. PMID:24475158
The numerical model of multi-layer insulation with a defined wrapping pattern immersed in superfluid helium

NASA Astrophysics Data System (ADS)

Malecha, Ziemowit; Lubryka, Eliza

2017-11-01

The numerical model of thin layers, characterized by a defined wrapping pattern can be a crucial element of many computational problems related to engineering and science. A motivating example is found in multilayer electrical insulation, which is an important component of superconducting magnets and other cryogenic installations. The wrapping pattern of the insulation can significantly affect heat transport and the performance of the considered instruments. The major objective of this study is to develop the numerical boundary conditions (BC) needed to model the wrapping pattern of thin insulation. An example of the practical application of the proposed BC includes the heat transfer of Rutherford NbTi cables immersed in super-fluid helium (He II) across thin layers of electrical insulation. The proposed BC and a mathematical model of heat transfer in He II are implemented in the open source CFD toolbox OpenFOAM. The implemented mathematical model and the BC are compared in the experiments. The study confirms that the thermal resistance of electrical insulation can be lowered by implementing the proper wrapping pattern. The proposed BC can be useful in the study of new patterns for wrapping schemes. The work has been supported by statutory funds from Polish Ministry for Science and Higher Education for the year of 2017.
Wettability Patterning for Enhanced Dropwise Condensation

NASA Astrophysics Data System (ADS)

Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

2014-11-01

Dropwise condensation (DwC), in order to be sustainable, requires removal of the condensate droplets. This removal is frequently facilitated by gravity. The rate of DwC heat transfer depends strongly on the maximum departing droplet diameter. Based on wettability patterning, we present a facile technique designed to control the maximum droplet size in DwC within vapor/air atmospheres, and demonstrate how this approach can be used to enhance the corresponding heat transfer rate. We examine various hydrophilic-superhydrophilic patterns, which, respectively sustain DwC and filmwise (FwC) condensation on the substrate. The fabrication method does notemploy any hydrophobizing agent. By juxtaposing parallel lines of hydrophilic (CA ~ 78°) and superhydrophilic (CA ~ 0°) regions on the condensing surface, we create alternating domains of DwC and FwC. The average droplet size on the DwC domain is reduced by ~ 60% compared to the theoretical maximum, which corresponds to the line width. We compare heat transfer rate between unpatternend DwC surfaces and patterned DwC surfaces. Even after sacrificing 40% of condensing area, we achieve up to 20% improvement in condensate collection rate using an interdigitated superhydrophilic pattern, inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern, particularly under higher vapor loadings in an air/vapor ambient atmosphere. NSF STTR Grant 1331817 via NBD Nano.

Experimental Investigation of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.

2011-01-01

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.
Determining heat loss into the environment based on comprehensive investigation of boiler performance characteristics

NASA Astrophysics Data System (ADS)

Lyubov, V. K.; Malygin, P. V.; Popov, A. N.; Popova, E. I.

2015-08-01

A refined procedure for determining heat loss into the environment from heat-generating installations is presented that takes into account the state of their lining and heat insulation quality. The fraction of radiative component in the total amount of heat loss through the outer surfaces is determined. The results from experimental investigations of the thermal engineering and environmental performance characteristics of a foreign hot-water boiler in firing wood pellets are presented. A conclusion is drawn about the possibility of using such hot-water boilers for supplying heat to low-rise buildings, especially for the conditions of the North-Arctic region. The results from a thermal engineering investigation of wood pellets and furnace residue carried out on installations of a thermal analysis laboratory are presented together with the grain-size composition of fuel and indicators characterizing the mechanical strength of wood pellets. The velocity fields, flue gas flow rates, and soot particle concentrations are determined using the external filtration methods, and the composition of combustion products is investigated using a gas analyzer. The graphs of variation with time of boiler external surface temperature from the moment of achieving the nominal mode of operation and heat loss into the environment for stationary boilers are presented.
Experimental Investigation of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.

2012-01-01

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.
Conflicts of thermal adaptation and fever--a cybernetic approach based on physiological experiments.

PubMed

Werner, J; Beckmann, U

1998-01-01

Cold adaptation aims primarily at a better economy, i.e., preservation of energy often at the cost of a lower mean body temperature during cold stress, whereas heat adaptation whether achieved by exposure to a hot environment or by endogenous heat produced by muscle exercise, often brings about a higher efficiency of control, i.e., a lower mean body temperature during heat stress, at the cost of a higher water loss. While cold adaptation is beneficial in a cold environment, it may constitute a detrimental factor for exposure to a hot environment, mainly because of morphological adaptation. Heat adaptation may be maladaptive for cold exposure, mainly because of functional adaptation. Heat adaptation clearly is best suited to avoid higher body temperatures in fever, no matter which environmental conditions prevail. On the other hand, cold adaptation is detrimental for coping with fever in hot environment. Yet, in the cold, preceding cold adaptation may, because of reduced metabolic heat production, result in lower febrile increase of body temperature. Apparently controversial effects and results may be analyzed in the framework of a cybernetic approach to the main mechanisms of thermal adaptation and fever. Morphological adaptations alter the properties of the heat transfer characteristics of the body ("passive system"), whereas functional adaptation and fever concern the subsystems of control, namely sensors, integrative centers and effectors. In a closed control-loop the two types of adaptation have totally different consequences. It is shown that the experimental results are consistent with the predictions of such an approach.
SIMULATION OF A BIOFEEDBACK MICROCLIMATE COOLING SYSTEM USING A HUMAN THERMOREGULATION MODEL

DTIC Science & Technology

2017-02-01

garment (LCG) The rate of LCG heat removal from the human body depends on coolant inlet temperature (Tin), clothing insulation worn over the LCG, flow...The efficiency η is equal to one when the outer clothing has sufficient insulation and the heat exchange between LCG and the external environment...0.27 m2·ºC·W-1 (1.73 clo). Insulation of protective ensembles prevent the LCG from absorbing heat from the environment (circulating liquid temperature
A radiant heating test facility for space shuttle orbiter thermal protection system certification

NASA Technical Reports Server (NTRS)

Sherborne, W. D.; Milhoan, J. D.

1980-01-01

A large scale radiant heating test facility was constructed so that thermal certification tests can be performed on the new generation of thermal protection systems developed for the space shuttle orbiter. This facility simulates surface thermal gradients, onorbit cold-soak temperatures down to 200 K, entry heating temperatures to 1710 K in an oxidizing environment, and the dynamic entry pressure environment. The capabilities of the facility and the development of new test equipment are presented.
Sequential and selective localized optical heating in water via on-chip dielectric nanopatterning.

PubMed

Morsy, Ahmed M; Biswas, Roshni; Povinelli, Michelle L

2017-07-24

We study the use of nanopatterned silicon membranes to obtain optically-induced heating in water. We show that by varying the detuning between an absorptive optical resonance of the patterned membrane and an illumination laser, both the magnitude and response time of the temperature rise can be controlled. This allows for either sequential or selective heating of different patterned areas on chip. We obtain a steady-state temperature of approximately 100 °C for a 805.5nm CW laser power density of 66 µW/μm 2 and observe microbubble formation. The ability to spatially and temporally control temperature on the microscale should enable the study of heat-induced effects in a variety of chemical and biological lab-on-chip applications.
Classifying Urban Space Types of Seoul using Time-series Heat Island map

NASA Astrophysics Data System (ADS)

Jung, S.; KIM, H.; JE, M.

2017-12-01

In August 2016, the hottest heat occurred in Korea since the weather observation started in Korea. Due to climate changes, this heat phenomenon is expected to be severe more in the future. Thus, this study analyzed the heatwave occurred in 2016 with regard to Seoul from various angles to identify the characteristics of urban regions where the heat island phenomenon occurred. To do this, first, temperature data for two days on August 6 and 12 in 2016 when the hottest heatwave occurred were collected from 287 places of automatic weather stations (AWS) installed in Seoul and adjacent suburbs. The temperature distribution of Seoul was mapped using interpolation in every hour using the collected temperature data. Second, regions in Seoul were classified using statistical methods based on spatial characteristics such as land coverage, density, use type, and traffic volume in Seoul. Third, a daily pattern of change in temperature in the classified regions was depicted with a graph, and regions were re-classified based on the daily pattern of change in temperature. Finally, the characteristics of the classified regions were re-reviewed and then, heat island occurrence, continuation, and reduction measure by region type were discussed. The analysis results showed that a pattern of heatwave occurrence was exhibited differently by the classified region type. The results also showed that not only physical characteristics such as land coverage but also socioeconomic index such as population density and floating population that induced a traffic volume influenced the pattern of heatwave occurrence despite of the same land usage regions. This study not only classified urban climate regions by existing mean temperature and specific time-point temperature but also proposed a methodology that analyzed heat island phenomenon inside cities by using time-series temperature data in a day. Furthermore, this study enabled regional classification based on heat island characteristics to contribute to establishment of measure for each regional classification.
Response of heat shock protein genes of the oriental fruit moth under diapause and thermal stress reveals multiple patterns dependent on the nature of stress exposure.

PubMed

Zhang, Bo; Peng, Yu; Zheng, Jincheng; Liang, Lina; Hoffmann, Ary A; Ma, Chun-Sen

2016-07-01

Heat shock protein gene (Hsp) families are thought to be important in thermal adaptation, but their expression patterns under various thermal stresses have still been poorly characterized outside of model systems. We have therefore characterized Hsp genes and their stress responses in the oriental fruit moth (OFM), Grapholita molesta, a widespread global orchard pest, and compared patterns of expression in this species to that of other insects. Genes from four Hsp families showed variable expression levels among tissues and developmental stages. Members of the Hsp40, 70, and 90 families were highly expressed under short exposures to heat and cold. Expression of Hsp40, 70, and Hsc70 family members increased in OFM undergoing diapause, while Hsp90 was downregulated. We found that there was strong sequence conservation of members of large Hsp families (Hsp40, Hsp60, Hsp70, Hsc70) across taxa, but this was not always matched by conservation of expression patterns. When the large Hsps as well as small Hsps from OFM were compared under acute and ramping heat stress, two groups of sHsps expression patterns were apparent, depending on whether expression increased or decreased immediately after stress exposure. These results highlight potential differences in conservation of function as opposed to sequence in this gene family and also point to Hsp genes potentially useful as bioindicators of diapause and thermal stress in OFM.
Evaluation of three thermal protection systems in a hypersonic high-heating-rate environment induced by an elevon deflected 30 deg

NASA Technical Reports Server (NTRS)

Taylor, A. H.; Jackson, L. R.; Weinstein, I.

1977-01-01

Three thermal protection systems proposed for a hypersonic research airplane were subjected to high heating rates in the Langley 8 foot, high temperature structures tunnel. Metallic heat sink (Lockalloy), reusable surface insulation, and insulator-ablator materials were each tested under similar conditions. The specimens were tested for a 10 second exposure on the windward side of an elevon deflected 30 deg. The metallic heat sink panel exhibited no damage; whereas the reusable surface insulation tiles were debonded from the panel and the insulator-ablator panel eroded through its thickness, thus exposing the aluminum structure to the Mach 7 environment.
Water Recovery with the Heat Melt Compactor in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Golliher, Eric L.; Goo, Jonathan; Fisher, John

2015-01-01

The Heat Melt Compactor is a proposed utility that will compact astronaut trash, extract the water for eventual re-use, and form dry square tiles that can be used as additional ionizing radiation shields for future human deep space missions. The Heat Melt Compactor has been under development by a consortium of NASA centers. The downstream portion of the device is planned to recover a small amount of water while in a microgravity environment. Drop tower low gravity testing was performed to assess the effect of small particles on a capillary-based water/air separation device proposed for the water recovery portion of the Heat Melt Compactor.
Analysis of Aerospike Plume Induced Base-Heating Environment

NASA Technical Reports Server (NTRS)

Wang, Ten-See

1998-01-01

Computational analysis is conducted to study the effect of an aerospike engine plume on X-33 base-heating environment during ascent flight. To properly account for the effect of forebody and aftbody flowfield such as shocks and to allow for potential plume-induced flow-separation, thermo-flowfield of trajectory points is computed. The computational methodology is based on a three-dimensional finite-difference, viscous flow, chemically reacting, pressure-base computational fluid dynamics formulation, and a three-dimensional, finite-volume, spectral-line based weighted-sum-of-gray-gases radiation absorption model computational heat transfer formulation. The predicted convective and radiative base-heat fluxes are presented.
Temperature Observation Time and Type Influence Estimates of Heat-Related Mortality in Seven U.S. Cities.

PubMed

Davis, Robert E; Hondula, David M; Patel, Anjali P

2016-06-01

Extreme heat is a leading weather-related cause of mortality in the United States, but little guidance is available regarding how temperature variable selection impacts heat-mortality relationships. We examined how the strength of the relationship between daily heat-related mortality and temperature varies as a function of temperature observation time, lag, and calculation method. Long time series of daily mortality counts and hourly temperature for seven U.S. cities with different climates were examined using a generalized additive model. The temperature effect was modeled separately for each hour of the day (with up to 3-day lags) along with different methods of calculating daily maximum, minimum, and mean temperature. We estimated the temperature effect on mortality for each variable by comparing the 99th versus 85th temperature percentiles, as determined from the annual time series. In three northern cities (Boston, MA; Philadelphia, PA; and Seattle, WA) that appeared to have the greatest sensitivity to heat, hourly estimates were consistent with a diurnal pattern in the heat-mortality response, with strongest associations for afternoon or maximum temperature at lag 0 (day of death) or afternoon and evening of lag 1 (day before death). In warmer, southern cities, stronger associations were found with morning temperatures, but overall the relationships were weaker. The strongest temperature-mortality relationships were associated with maximum temperature, although mean temperature results were comparable. There were systematic and substantial differences in the association between temperature and mortality based on the time and type of temperature observation. Because the strongest hourly temperature-mortality relationships were not always found at times typically associated with daily maximum temperatures, temperature variables should be selected independently for each study location. In general, heat-mortality was more closely coupled to afternoon and maximum temperatures in most cities we examined, particularly those typically prone to heat-related mortality. Davis RE, Hondula DM, Patel AP. 2016. Temperature observation time and type influence estimates of heat-related mortality in seven U.S. cities. Environ Health Perspect 124:795-804; http://dx.doi.org/10.1289/ehp.1509946.
Comparative Assessment of the Effects of Climate Change on Heat- and Cold-Related Mortality in the United Kingdom and Australia

PubMed Central

Dear, Keith; Hajat, Shakoor; Heaviside, Clare; Eggen, Bernd; McMichael, Anthony J.

2014-01-01

Background: High and low ambient temperatures are associated with increased mortality in temperate and subtropical climates. Temperature-related mortality patterns are expected to change throughout this century because of climate change. Objectives: We compared mortality associated with heat and cold in UK regions and Australian cities for current and projected climates and populations. Methods: Time-series regression analyses were carried out on daily mortality in relation to ambient temperatures for UK regions and Australian cities to estimate relative risk functions for heat and cold and variations in risk parameters by age. Excess deaths due to heat and cold were estimated for future climates. Results: In UK regions, cold-related mortality currently accounts for more than one order of magnitude more deaths than heat-related mortality (around 61 and 3 deaths per 100,000 population per year, respectively). In Australian cities, approximately 33 and 2 deaths per 100,000 population are associated every year with cold and heat, respectively. Although cold-related mortality is projected to decrease due to climate change to approximately 42 and 19 deaths per 100,000 population per year in UK regions and Australian cities, heat-related mortality is projected to increase to around 9 and 8 deaths per 100,000 population per year, respectively, by the 2080s, assuming no changes in susceptibility and structure of the population. Conclusions: Projected changes in climate are likely to lead to an increase in heat-related mortality in the United Kingdom and Australia over this century, but also to a decrease in cold-related deaths. Future temperature-related mortality will be amplified by aging populations. Health protection from hot weather will become increasingly necessary in both countries, while protection from cold weather will be still needed. Citation: Vardoulakis S, Dear K, Hajat S, Heaviside C, Eggen B, McMichael AJ. 2014. Comparative assessment of the effects of climate change on heat- and cold-related mortality in the United Kingdom and Australia. Environ Health Perspect 122:1285–1292; http://dx.doi.org/10.1289/ehp.1307524 PMID:25222967
Carbon dioxide and energy fluxes over a large shallow lake in China

NASA Astrophysics Data System (ADS)

Zhao, Xiaosong

2017-04-01

The turbulent exchange of carbon dioxide and energy between water and atmosphere over lakes differ from those over vegetated surfaces due to high heat capacity of water and different water ecological environment. For a shallow lake, the underlying surface generally changes between water covered and land covered with water level fluctuation, which significantly influences carbon dioxide and energy fluxes. Continuous measurement of the carbon dioxide (CO2), latent (LE) and sensible (H) heat fluxes was made using the eddy covariance method over the Poyang Lake, the largest fresh lake in China, from August 2013 to December 2015. Results indicated that the surface energy budget has a strong seasonal pattern, with peaks in LE and H observed in early August and September. There was 10 days delay between the net radiation and the latent heat flux. More net radiation (Rn) was allocated to the LE rather than H through the year, with monthly mean LE/Rn of 0.65 and H/Rn of 0.11, which caused Bowen ratio was 0.15 in water-covered period, lower than that in land-covered period. The water heat storage experienced shifting from heat storage to heat release, with maximum heat storage in July and maximum heat release in September. The water heat advection was account for 4% to 10% of Rn and peaked in June. The annual evaporation is 875 mm, 893 mm and 1019 mm in 2013 (from August 2013 to July 2014), 2014 and 2015, which was account for approximately 57% of precipitation in the three years. The large lake acted as a CO2 source in inundating period and a CO2 sink in exposure period. The energy fluxes were controlled by environmental factors with timescale dependence. On daily scale, the LE and H were highly correlated with product of wind speed and vapor pressure deficit (UVPD) or wind speed (U) in the water-covered period, and with Rn in the land-covered period. Monthly LE, H and annual H were controlled by Rn, while annual LE was primarily dependent on water depth. Annual CO2 budget was regulated by duration of inundating period.
Coupling indoor airflow, HVAC, control and building envelope heat transfer in the Modelica Buildings library

DOE PAGES

Zuo, Wangda; Wetter, Michael; Tian, Wei; ...

2015-07-13

Here, this paper describes a coupled dynamic simulation of an indoor environment with heating, ventilation, and air conditioning (HVAC) systems, controls and building envelope heat transfer. The coupled simulation can be used for the design and control of ventilation systems with stratified air distributions. Those systems are commonly used to reduce building energy consumption while improving the indoor environment quality. The indoor environment was simulated using the fast fluid dynamics (FFD) simulation programme. The building fabric heat transfer, HVAC and control system were modelled using the Modelica Buildings library. After presenting the concept, the mathematical algorithm and the implementation ofmore » the coupled simulation were introduced. The coupled FFD–Modelica simulation was then evaluated using three examples of room ventilation with complex flow distributions with and without feedback control. Lastly, further research and development needs were also discussed.« less
Coupling indoor airflow, HVAC, control and building envelope heat transfer in the Modelica Buildings library

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

Zuo, Wangda; Wetter, Michael; Tian, Wei

Here, this paper describes a coupled dynamic simulation of an indoor environment with heating, ventilation, and air conditioning (HVAC) systems, controls and building envelope heat transfer. The coupled simulation can be used for the design and control of ventilation systems with stratified air distributions. Those systems are commonly used to reduce building energy consumption while improving the indoor environment quality. The indoor environment was simulated using the fast fluid dynamics (FFD) simulation programme. The building fabric heat transfer, HVAC and control system were modelled using the Modelica Buildings library. After presenting the concept, the mathematical algorithm and the implementation ofmore » the coupled simulation were introduced. The coupled FFD–Modelica simulation was then evaluated using three examples of room ventilation with complex flow distributions with and without feedback control. Lastly, further research and development needs were also discussed.« less
40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in § 63.101...
40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 14 2014-07-01 2014-07-01 false Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in § 63.101...
40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 14 2012-07-01 2011-07-01 true Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in § 63.101...

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 14 2013-07-01 2013-07-01 false Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in § 63.101...
40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 13 2011-07-01 2011-07-01 false Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in § 63.101...
Ground-Coupled Heating-Cooling Systems in Urban Areas: How Sustainable Are They?

ERIC Educational Resources Information Center

Younger, Paul L.

2008-01-01

Ground-coupled heating-cooling systems (GCHCSs) exchange heat between the built environment and the subsurface using pipework buried in trenches or boreholes. If heat pumps in GCHCSs are powered by "green electricity," they offer genuine carbon-free heating-cooling; for this reason, there has been a surge in the technology in recent…
Evolutionary rescue and local adaptation under different rates of temperature increase: a combined analysis of changes in phenotype expression and genotype frequency in Paramecium microcosms.

PubMed

Killeen, Joshua; Gougat-Barbera, Claire; Krenek, Sascha; Kaltz, Oliver

2017-04-01

Evolutionary rescue (ER) occurs when populations, which have declined due to rapid environmental change, recover through genetic adaptation. The success of this process and the evolutionary trajectory of the population strongly depend on the rate of environmental change. Here we investigated how different rates of temperature increase (from 23 to 32 °C) affect population persistence and evolutionary change in experimental microcosms of the protozoan Paramecium caudatum. Consistent with theory on ER, we found that those populations experiencing the slowest rate of temperature increase were the least likely to become extinct and tended to be the best adapted to the new temperature environment. All high-temperature populations were more tolerant to severe heat stress (35, 37 °C), indicating a common mechanism of heat protection. High-temperature populations also had superior growth rates at optimum temperatures, leading to the absence of a pattern of local adaptation to control (23 °C) and high-temperature (32 °C) environments. However, high-temperature populations had reduced growth at low temperatures (5-9 °C), causing a shift in the temperature niche. In part, the observed evolutionary change can be explained by selection from standing variation. Using mitochondrial markers, we found complete divergence between control and high-temperature populations in the frequencies of six initial founder genotypes. Our results confirm basic predictions of ER and illustrate how adaptation to an extreme local environment can produce positive as well as negative correlated responses to selection over the entire range of the ecological niche. © 2017 John Wiley & Sons Ltd.
Toward Evaluating the Predictability of Arctic-related Climate Variations: Initial Results from ArCS Project Theme 5

NASA Astrophysics Data System (ADS)

Hasumi, H.

2016-12-01

We present initial results from the theme 5 of the project ArCS, which is a national flagship project for Arctic research in Japan. The goal of theme 5 is to evaluate the predictability of Arctic-related climate variations, wherein we aim to: (1) establish the scientific basis of climate predictability; and (2) develop a method for predicting/projecting medium- and long-term climate variations. Variability in the Arctic environment remotely influences middle and low latitudes. Since some of the processes specific to the Arctic environment function as a long memory of the state of the climate, understanding of the process of remote connections would lead to higher-precision and longer-term prediction of global climate variations. Conventional climate models have large uncertainty in the Arctic region. By making Arctic processes in climate models more sophisticated, we aim to clarify the role of multi-sphere interaction in the Arctic environment. In this regard, our newly developed high resolution ice-ocean model has revealed the relationship between the oceanic heat transport into the Arctic Ocean and the synoptic scale atmospheric variability. We also aim to reveal the mechanism of remote connections by conducting climate simulations and analyzing various types of climate datasets. Our atmospheric model experiments under possible future situations of Arctic sea ice cover indicate that reduction of sea ice qualitatively alters the basic mechanism of remote connection. Also, our analyses of climate data have identified the cause of recent more frequent heat waves at Eurasian mid-to-high latitudes and clarified the dynamical process which forms the West Pacific pattern, a dominant mode of the atmospheric anomalous circulation in the West Pacific region which also exhibits a significant signal in the Arctic stratosphere.
Nocturnal behavior by a diurnal ape, the West African chimpanzee (Pan troglodytes verus), in a savanna environment at Fongoli, Senegal.

PubMed

Pruetz, Jill D

2018-02-08

I report on the nocturnal behavior of Fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. I predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. I observed chimpanzees for 403 hrs on 40 nights between 2007 and 2013 and categorized their activity as social, movement, or vocalization. I scored their activity as occurring after moonrise or before moonset and considered the influence of moon phase (fuller versus darker phases) as well as season on chimpanzee nocturnal behavior in the analyses. Results indicate that apes were more active after moonrise or before moonset during fuller moon phases in the dry season but not the wet season. Most night-time activity involved movement (travel or forage), followed by social behavior, and long-distance vocal communication. Animals in highly seasonal habitats often exhibit thermoregulatory adaptations but, like other primates, chimpanzees lack physiological mechanisms to combat thermal stress. This study provides evidence that they may exhibit behaviors that allow them to avoid high temperatures in a savanna environment, such as feeding and socializing at night during the hottest time of year and in the brightest moon phases. The results support theories invoking thermal stress as a selective pressure for hominins in open environments where heat would constrain temporal foraging niches, and suggest an adaptability of sleeping patterns in response to external factors. © 2018 Wiley Periodicals, Inc.
Numerical simulations of drainage flows on Mars

NASA Technical Reports Server (NTRS)

Parish, Thomas R.; Howard, Alan D.

1992-01-01

Data collected by Viking Landers have shown that the meteorology of the near surface Martian environment is analogous to desertlike terrestrial conditions. Geological evidence such as dunes and frost streaks indicate that the surface wind is a potentially important factor in scouring of the martian landscape. In particular, the north polar basin shows erosional features that suggest katabatic wind convergence into broad valleys near the margin of the polar cap. The pattern of katabatic wind drainage off the north polar cap is similar to that observed on Earth over Antarctica or Greenland. The sensitivity is explored of Martian drainage flows to variations in terrain slope and diurnal heating using a numerical modeling approach. The model used is a 2-D sigma coordinate primitive equation system that has been used for simulations of Antarctic drainage flows. Prognostic equations include the flux forms of the horizontal scalar momentum equations, temperature, and continuity. Parameterization of both longwave (terrestrial) and shortwave (solar) radiation is included. Turbulent transfer of heat and momentum in the Martian atmosphere remains uncertain since relevant measurements are essentially nonexistent.
Systemic Analysis of Heat Shock Response Induced by Heat Shock and a Proteasome Inhibitor MG132

PubMed Central

Kim, Hee-Jung; Joo, Hye Joon; Kim, Yung Hee; Ahn, Soyeon; Chang, Jun; Hwang, Kyu-Baek; Lee, Dong-Hee; Lee, Kong-Joo

2011-01-01

The molecular basis of heat shock response (HSR), a cellular defense mechanism against various stresses, is not well understood. In this, the first comprehensive analysis of gene expression changes in response to heat shock and MG132 (a proteasome inhibitor), both of which are known to induce heat shock proteins (Hsps), we compared the responses of normal mouse fibrosarcoma cell line, RIF- 1, and its thermotolerant variant cell line, TR-RIF-1 (TR), to the two stresses. The cellular responses we examined included Hsp expressions, cell viability, total protein synthesis patterns, and accumulation of poly-ubiquitinated proteins. We also compared the mRNA expression profiles and kinetics, in the two cell lines exposed to the two stresses, using microarray analysis. In contrast to RIF-1 cells, TR cells resist heat shock caused changes in cell viability and whole-cell protein synthesis. The patterns of total cellular protein synthesis and accumulation of poly-ubiquitinated proteins in the two cell lines were distinct, depending on the stress and the cell line. Microarray analysis revealed that the gene expression pattern of TR cells was faster and more transient than that of RIF-1 cells, in response to heat shock, while both RIF-1 and TR cells showed similar kinetics of mRNA expression in response to MG132. We also found that 2,208 genes were up-regulated more than 2 fold and could sort them into three groups: 1) genes regulated by both heat shock and MG132, (e.g. chaperones); 2) those regulated only by heat shock (e.g. DNA binding proteins including histones); and 3) those regulated only by MG132 (e.g. innate immunity and defense related molecules). This study shows that heat shock and MG132 share some aspects of HSR signaling pathway, at the same time, inducing distinct stress response signaling pathways, triggered by distinct abnormal proteins. PMID:21738571
Using a conformal water bolus to adjust heating patterns of microwave waveguide applicators

NASA Astrophysics Data System (ADS)

Stauffer, Paul R.; Rodrigues, Dario B.; Sinahon, Randolf; Sbarro, Lyndsey; Beckhoff, Valeria; Hurwitz, Mark D.

2017-02-01

Background: Hyperthermia, i.e., raising tissue temperature to 40-45°C for 60 min, has been demonstrated to increase the effectiveness of radiation and chemotherapy for cancer. Although multi-element conformal heat applicators are under development to provide more adjustable heating of contoured anatomy, to date the most often used applicator to heat superficial disease is the simple microwave waveguide. With only a single power input, the operator must be resourceful to adjust heat treatment to accommodate variable size and shape tumors spreading across contoured anatomy. Methods: We used multiphysics simulation software that couples electromagnetic, thermal and fluid dynamics physics to simulate heating patterns in superficial tumors from commercially available microwave waveguide applicators. Temperature distributions were calculated inside homogenous muscle and layered skin-fat-muscle-tumor-bone tissue loads for a typical range of applicator coupling configurations and size of waterbolus. Variable thickness waterbolus was simulated as necessary to accommodate contoured anatomy. Physical models of several treatment configurations were constructed for comparison of simulation results with experimental specific absorption rate (SAR) measurements in homogenous muscle phantom. Results: Accuracy of the simulation model was confirmed with experimental SAR measurements of three unique applicator setups. Simulations demonstrated the ability to generate a wide range of power deposition patterns with commercially available waveguide antennas by controllably varying size and thickness of the waterbolus layer. Conclusion: Heating characteristics of 915 MHz waveguide antennas can be varied over a wide range by controlled adjustment of microwave power, coupling configuration, and waterbolus lateral size and thickness. The uniformity of thermal dose delivered to superficial tumors can be improved by cyclic switching of waterbolus thickness during treatment to proactively shift heat peaks and nulls around under the aperture, thereby reducing patient pain while increasing minimum thermal dose by end of treatment.
Adaptable Single Active Loop Thermal Control System (TCS) for Future Space Missions

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Lee, Seunghyun; Hasan, Mohammad

2015-01-01

This presentation will examine the development of a thermal control system (TCS) for future space missions utilizing a single active cooling loop. The system architecture enables the TCS to be reconfigured during the various mission phases to respond, not only to varying heat load, but to heat rejection temperature as well. The system will consist of an accumulator, pump, cold plates (evaporators), condenser radiator, and compressor, in addition to control, bypass and throttling valves. For cold environments, the heat will be rejected by radiation, during which the compressor will be bypassed, reducing the system to a simple pumped loop that, depending on heat load, can operate in either a single-phase liquid mode or two-phase mode. For warmer environments, the pump will be bypassed, enabling the TCS to operate as a heat pump. This presentation will focus on recent findings concerning two-phase flow regimes, pressure drop, and heat transfer coefficient trends in the cabin and avionics micro-channel heat exchangers when using the heat pump mode. Also discussed will be practical implications of using micro-channel evaporators for the heat pump.
Physiological Responses in a Variable Environment: Relationships between Metabolism, Hsp and Thermotolerance in an Intertidal-Subtidal Species

PubMed Central

Wang, Qing-lin; Dong, Shuang-lin

2011-01-01

Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky–eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins) and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps) occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT). The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment. PMID:22022615
Bioengineering thermodynamics of biological cells.

PubMed

Lucia, Umberto

2015-12-01

Cells are open complex thermodynamic systems. They can be also regarded as complex engines that execute a series of chemical reactions. Energy transformations, thermo-electro-chemical processes and transports phenomena can occur across the cells membranes. Moreover, cells can also actively modify their behaviours in relation to changes in their environment. Different thermo-electro-biochemical behaviours occur between health and disease states. But, all the living systems waste heat, which is no more than the result of their internal irreversibility. This heat is dissipated into the environment. But, this wasted heat represent also a sort of information, which outflows from the cell toward its environment, completely accessible to any observer. The analysis of irreversibility related to this wasted heat can represent a new approach to study the behaviour of the cells themselves and to control their behaviours. So, this approach allows us to consider the living systems as black boxes and analyze only the inflows and outflows and their changes in relation to the modification of the environment. Therefore, information on the systems can be obtained by analyzing the changes in the cell heat wasted in relation to external perturbations. The bioengineering thermodynamics bases are summarized and used to analyse possible controls of the calls behaviours based on the control of the ions fluxes across the cells membranes.
On a Heat Exchange Problem under Sharply Changing External Conditions

NASA Astrophysics Data System (ADS)

Khishchenko, K. V.; Charakhch'yan, A. A.; Shurshalov, L. V.

2018-02-01

The heat exchange problem between carbon particles and an external environment (water) is stated and investigated based on the equations of heat conducting compressible fluid. The environment parameters are supposed to undergo large and fast variations. In the time of about 100 μs, the temperature of the environment first increases from the normal one to 2400 K, is preserved at this level for about 60 μs, and then decreases to 300 K during approximately 50 μs. At the same periods of time, the pressure of the external environment increases from the normal one to 67 GPa, is preserved at this level, and then decreases to zero. Under such external conditions, the heating of graphite particles of various sizes, their phase transition to the diamond phase, and the subsequent unloading and cooling almost to the initial values of the pressure and temperature without the reverse transition from the diamond to the graphite phase are investigated. Conclusions about the maximal size of diamond particles that can be obtained in experiments on the shock compression of the mixture of graphite with water are drawn.
Morphology of single inhalable particle in the air polluted city of Shijiazhuang, China.

PubMed

Wang, Zanhong; Zhang, Lingzhi; Zhang, Yuliang; Zhao, Zhou; Zhang, Sumin

2008-01-01

In the typical air polluted city of Shijiazhuang, single inhalable particle samples in non-heating period, heating period, dust storm days, and snowy days were collected and detected by SEM/EDS (scanning electron microscopy and energy dispersive X-ray spectrometry). The particle morphology was characterized by the 6 shape clusters, which are: irregular square, agglomerate, sphere, floccule, column or stick, and unknown, by quantitative order. The irregular square particles are common in all kinds of samples; sphere particles are more, and column or stick are less in winter samples; in the wet deposit samples, agglomerate and floccule particles are not found. The surface of most particles is coarse with fractal edge, which can provide suitable chemical reaction bed in the polluted atmospheric environment. New formed calcium crystal is found to demonstrate the existence of neutralized reaction, explaining the reason for the high SO2 emission and low acid rain frequency in Shijiazhuang. The three sorts of surface patterns of spheres are smooth, semi-smooth, and coarse, corresponding to the element of Si-dominant, Si-Al-dominant, and Fe-dominant. The soot particle is present as floccule with average size around 10 microm, considerably larger than the former reported results, but wrapped or captured with other fine particles to make its appearance unique and enhance its toxicity potentially. The new formed calcium crystal, the 3 sorts of sphere surface patterns, and the unique soot appearance represent the single inhalable particle's morphology characteristics in Shijiazhuang City.
Potential pathogens, antimicrobial patterns and genotypic diversity of Escherichia coli isolates in constructed wetlands treating swine wastewater.

PubMed

Ibekwe, A M; Murinda, Shelton E; DebRoy, Chitrita; Reddy, Gudigopura B

2016-02-01

Escherichia coli populations originating from swine houses through constructed wetlands were analyzed for potential pathogens, antimicrobial susceptibility patterns, and genotypic diversity. Escherichia coli isolates (n = 493) were screened for the presence of the following virulence genes: stx1, stx2 and eae (Shiga toxin-producing E. coli [STEC]), heat-labile enterotoxin (LT) genes and heat stable toxin STa and STb (enterotoxigenic E. coli (ETEC), cytotoxin necrotizing factors 1 and 2 (cnf1 and cnf2 [necrotoxigenic E. coli- NTEC]), as well as O and H antigens, and the presence of the antibiotic resistance genes blaTEM, blaSHV, blaCMY-2, tet A, tet B, tet C, mph(A), aadA, StrA/B, sul1, sul2 and sul3. The commensal strains were further screened for 16 antimicrobials and characterized by BOX AIR-1 PCR for unique genotypes. The highest antibiotic resistance prevalence was for tetracycline, followed by erythromycin, ampicillin, streptomycin, sulfisoxazole and kanamycin. Our data showed that most of the isolates had high distribution of single or multidrug-resistant (MDR) genotypes. Therefore, the occurrence of MDR E. coli in the wetland is a matter of great concern due to possible transfer of resistance genes from nonpathogenic to pathogenic strains or vice versa in the environment. Published by Oxford University Press on behalf of FEMS 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Multilocus adaptation associated with heat resistance in reef-building corals.

PubMed

Bay, Rachael A; Palumbi, Stephen R

2014-12-15

The evolution of tolerance to future climate change depends on the standing stock of genetic variation for resistance to climate-related impacts, but genes contributing to climate tolerance in wild populations are poorly described in number and effect. Physiology and gene expression patterns have shown that corals living in naturally high-temperature microclimates are more resistant to bleaching because of both acclimation and fixed effects, including adaptation. To search for potential genetic correlates of these fixed effects, we genotyped 15,399 single nucleotide polymorphisms (SNPs) in 23 individual tabletop corals, Acropora hyacinthus, within a natural temperature mosaic in backreef lagoons on Ofu Island, American Samoa. Despite overall lack of population substructure, we identified 114 highly divergent SNPs as candidates for environmental selection, via multiple stringent outlier tests, and correlations with temperature. Corals from the warmest reef location had higher minor allele frequencies across these candidate SNPs, a pattern not seen for noncandidate loci. Furthermore, within backreef pools, colonies in the warmest microclimates had a higher number and frequency of alternative alleles at candidate loci. These data suggest mild selection for alternate alleles at many loci in these corals during high heat episodes and possible maintenance of extensive polymorphism through multilocus balancing selection in a heterogeneous environment. In this case, a natural population harbors a reservoir of alleles preadapted to high temperatures, suggesting potential for future evolutionary response to climate change. Copyright © 2014 Elsevier Ltd. All rights reserved.
Heat flow in relation to hydrothermal activity in the southern Black Rock Desert, Nevada

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

Sass, J.H.; Zoback, M.L.; Galanis, S.P. Jr.

1979-01-01

As part of an investigation of the Gerlach NE KGRA (Known Geothermal Resource Area) a number of heat-flow measurements were made in playa sediments of the southern Black Rock Desert, northwestern Nevada. These data together with additional previously unpublished heat-flow values reveal a complex pattern of heat flow with values ranging between 1.0 to 5.0 HFU (40 to 100 mWm/sup -2/) outside of the hot springs area. The mean heat flow for the 13 reported sites in the southern Black Rock Desert is 1.8 +- 0.15 HFU (75 +- 6 mWm/sup -2/). The complexity of the pattern of heat flowmore » is believed to arise from hydrothermal circulation supporting the numerous hot springs throughout the region. The fact that the lowest observed heat flow occurs in the deepest part of the basin strongly suggests that fluid movement within the basin represents part of the recharge for the hydrothermal system. A thermal balance for the system incorporating both anomalous conductive heat loss and convective heat loss from the spring systems indicate a total energy loss of about 8.0 Mcal/sec or 34 megawatts over an estimated 1000 km/sup 2/ region. Consideration of this additional heat loss yields a mean regional heat flow of 2.5 + HFU (100 + mWm/sup -2/) and warrants inclusion of this region in the Battle Mountain heat-flow high (Lachenbruch and Sass, 1977, 1978).« less
Hypersonic engine component experiments in high heat flux, supersonic flow environment

NASA Technical Reports Server (NTRS)

Gladden, Herbert J.; Melis, Matthew E.

1993-01-01

A major concern in advancing the state-of-the-art technologies for hypersonic vehicles is the development of an aeropropulsion system capable of withstanding the sustained high thermal loads expected during hypersonic flight. Even though progress has been made in the computational understanding of fluid dynamics and the physics/chemistry of high speed flight, there is also a need for experimental facilities capable of providing a high heat flux environment for testing component concepts and verifying/calibrating these analyses. A hydrogen/oxygen rocket engine heat source was developed at the NASA Lewis Research Center as one element in a series of facilities at national laboratories designed to fulfill this need. This 'Hot Gas Facility' is capable of providing heat fluxes up to 450 w/sq cm on flat surfaces and up to 5,000 w/sq cm at the leading edge stagnation point of a strut in a supersonic flow stream. Gas temperatures up to 3050 K can also be attained. Two recent experimental programs conducted in this facility are discussed. The objective of the first experiment is to evaluate the erosion and oxidation characteristics of a coating on a cowl leading edge (or strut leading edge) in a supersonic, high heat flux environment. Macrophotographic data from a coated leading edge model show progressive degradation over several thermal cycles at aerothermal conditions representative of high Mach number flight. The objective of the second experiment is to assess the capability of cooling a porous surface exposed to a high temperature, high velocity flow environment and to provide a heat transfer data base for a design procedure. Experimental results from transpiration cooled surfaces in a supersonic flow environment are presented.
Pain modulation during drives through cold and hot virtual environments.

PubMed

Mühlberger, Andreas; Wieser, Matthias J; Kenntner-Mabiala, Ramona; Pauli, Paul; Wiederhold, Brenda K

2007-08-01

Evidence exists that virtual worlds reduce pain perception by providing distraction. However, there is no experimental study to show that the type of world used in virtual reality (VR) distraction influences pain perception. Therefore, we investigated whether pain triggered by heat or cold stimuli is modulated by "warm "or "cold " virtual environments and whether virtual worlds reduce pain perception more than does static picture presentation. We expected that cold worlds would reduce pain perception from heat stimuli, while warm environments would reduce pain perception from cold stimuli. Additionally, both virtual worlds should reduce pain perception in general. Heat and cold pain stimuli thresholds were assessed outside VR in 48 volunteers in a balanced crossover design. Participants completed three 4-minute assessment periods: virtual "walks " through (1) a winter and (2) an autumn landscape and static exposure to (3) a neutral landscape. During each period, five heat stimuli or three cold stimuli were delivered via a thermode on the participant's arm, and affective and sensory pain perceptions were rated. Then the thermode was changed to the other arm, and the procedure was repeated with the opposite pain stimuli (heat or cold). We found that both warm and cold virtual environments reduced pain intensity and unpleasantness for heat and cold pain stimuli when compared to the control condition. Since participants wore a head-mounted display (HMD) in both the control condition and VR, we concluded that the distracting value of virtual environments is not explained solely by excluding perception of the real world. Although VR reduced pain unpleasantness, we found no difference in efficacy between the types of virtual world used for each pain stimulus.
Nanoflare vs Footpoint Heating : Observational Signatures

NASA Technical Reports Server (NTRS)

Winebarger, Amy; Alexander, Caroline; Lionello, Roberto; Linker, Jon; Mikic, Zoran; Downs, Cooper

2015-01-01

Time lag analysis shows very long time lags between all channel pairs. Impulsive heating cannot address these long time lags. 3D Simulations of footpoint heating shows a similar pattern of time lags (magnitude and distribution) to observations. Time lags and relative peak intensities may be able to differentiate between TNE and impulsive heating solutions. Adding a high temperature channel (like XRT Be-thin) may improve diagnostics.

40 CFR 75.36 - Missing data procedures for heat input rate determinations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate is...
40 CFR 75.36 - Missing data procedures for heat input rate determinations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate is...
40 CFR 75.36 - Missing data procedures for heat input rate determinations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate is...
40 CFR 75.36 - Missing data procedures for heat input rate determinations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate is...
40 CFR 75.36 - Missing data procedures for heat input rate determinations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate is...
40 CFR 63.1435 - Heat exchanger provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Heat exchanger provisions. 63.1435... Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63.1435 Heat exchanger... for heat exchange systems, with the exceptions noted in paragraphs (b) through (e) of this section. (b...
40 CFR 63.1435 - Heat exchanger provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Heat exchanger provisions. 63.1435... Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63.1435 Heat exchanger... for heat exchange systems, with the exceptions noted in paragraphs (b) through (e) of this section. (b...
Cost-Effective Fabrication of Wettability Gradient Copper Surface by Screen Printing and its Application to Condensation Heat Transfer

NASA Astrophysics Data System (ADS)

Leu, Tzong-Shyng; Huang, Hung-Ming; Huang, Ding-Jun

2016-06-01

In this paper, wettability gradient pattern is applied to condensation heat transfer on a copper tube surface. For this application, the vital issue is how to fabricate gradient patterns on a curve tube surface to accelerate the droplet collection efficiently. For this purpose, novel fabrication processes are developed to form wettability gradient patterns on a curve copper tube surface by using roller screen printing surface modification techniques. The roller screen printing surface modification techniques can easily realize wettability gradient surfaces with superhydrophobicity and superhydrophilicity on a copper tube surface. Experimental results show the droplet nucleation sites, movement and coalescence toward the collection areas can be effectively controlled which can assist in removing the condensation water from the surface. The effectiveness of droplet collection is appropriate for being applied to condensation heat transfer in the foreseeable future.
Visualization techniques to experimentally model flow and heat transfer in turbine and aircraft flow passages

NASA Technical Reports Server (NTRS)

Russell, Louis M.; Hippensteele, Steven A.

1991-01-01

Increased attention to fuel economy and increased thrust requirements have increased the demand for higher aircraft gas turbine engine efficiency through the use of higher turbine inlet temperatures. These higher temperatures increase the importance of understanding the heat transfer patterns which occur throughout the turbine passages. It is often necessary to use a special coating or some form of cooling to maintain metal temperatures at a level which the metal can withstand for long periods of time. Effective cooling schemes can result in significant fuel savings through higher allowable turbine inlet temperatures and can increase engine life. Before proceeding with the development of any new turbine it is economically desirable to create both mathematical and experimental models to study and predict flow characteristics and temperature distributions. Some of the methods are described used to physically model heat transfer patterns, cooling schemes, and other complex flow patterns associated with turbine and aircraft passages.
Identifying and monitoring urban heat island in Bucharest using satellite time series and low cost meteorological sensors

NASA Astrophysics Data System (ADS)

Sandric, Ionut; Onose, Diana; Vanau, Gabriel; Ioja, Cristian

2016-04-01

The present study is focusing on the identification of urban heat island in Bucharest using both remote sensing products and low cost temperature sensors. The urban heat island in Bucharest was analyzed through a network of sensors located in 56 points (47 inside the administrative boundary of the city, 9 outside) 2009-2011. The network lost progressively its initial density, but was reformed during a new phase, 2013-2015. Time series satellite images from MODIS were intersected with the sensors for both phases. Statistical analysis were conducted to identify the temporal and spatial pattern of extreme temperatures in Bucharest. Several environmental factors like albedou, presence and absence of vegetation were used to fit a regression model between MODIS satellite products sensors in order to upscale the temperatures values recorded by MODIS For Bucharest, an important role for air temperature values in urban environments proved to have the local environmental conditions that leads to differences in air temperature at Bucharest city scale between 3-5 °C (both in the summer and in the winter). The UHI maps shows a good correlation with the presence of green areas. Differences in air temperature between higher tree density areas and isolated trees can reach much higher values, averages over 24 h periods still are in the 3-5 °C range The results have been obtained within the project UCLIMESA (Urban Heat Island Monitoring under Present and Future Climate), ongoing between 2013 and 2015 in the framework of the Programme for Research-DevelopmentInnovation for Space Technology and Advanced Research (STAR), administrated by the Romanian Space Agency Keywords: time series, urban heat island
Thermal Vacuum Integrated System Test at B-2

NASA Technical Reports Server (NTRS)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.
The Galapagos Spreading Center at 86°W: A detailed geothermal field study

NASA Astrophysics Data System (ADS)

Green, Kenneth E.; von Herzen, Richard P.; Williams, David L.

1981-02-01

Appendix is available with entire article on microfiche. Orderfrom American Geophysical Union, 2000 Florida Avenue, N.W.,Washington, D.C. 20009. Document J80-013; $01.00. Payment mustaccompany order. We report here measurements of the heat flow field of the Galapagos Spreading Center on crust of age less than 1.0 m.y. The 443 measurements in an area of about 570 km2 reveal the general planform of the geothermal flux and permit the first truly areal estimate of the near-axis conductive heat flux. The intrusion process and associated hydrothermal circulation dominate the surface heat flow pattern, with circulation apparently continuing beyond the limits of our survey. The areal average of the conductive heat flux is 7.1 ± 0.8 HFU (295 ± 33 mW/m2), about one-third the heat flux predicted by plate models. The remaining heat is apparently removed by venting of hydrothermal waters at the spreading axis and through basalt outcrops and hydrothermal mounds off axis. The pattern of surface heat flux is lineated parallel to the axis and the strongly lineated topography. Sharp lateral gradients in the heat flow, greater than 10 HFU/km near escarpments and commonly expressed as high heat flow at the tops of the scarps and lower heat flow in the valleys, may indicate a local concentration of the circulation by surface fault systems and/or variable sediment thickness.
Terrestrial heat flow in east and southern Africa

NASA Astrophysics Data System (ADS)

Nyblade, Andrew A.; Pollack, Henry N.; Jones, D. L.; Podmore, Francis; Mushayandebvu, Martin

1990-10-01

We report 26 new heat flow and 13 radiogenic heat production measurements from Zimbabwe, Zambia and Tanzania, together with details and some revisions of 18 previous heat flow measurements by other investigators from Kenya and Tanzania. These measurements come from Archean cratons, Proterozoic mobile belts, and Mesozoic and Cenozoic rifts. Heat flow data from eight new sites in the Archean Zimbabwe Craton are consistent with previous measurements in the Archean Kaapvaal-Zimbabwe Craton and Limpopo Belt (Kalahari Craton) and do not change the mean heat flow of 47±2 mW m-2 (standard error of the mean) in the Kalahari Craton based on 53 previous measurements. Eight new sites in the Archean Tanzania Craton give a mean heat flow of 34±4 mW m-2. The mean heat flow from nine sites in the Proterozoic Mozambique Belt to the east of the Tanzania Craton in Kenya and Tanzania is 47±4 mW m-2. Twelve measurements in the Mesozoic rifted continental margin in east Africa give a mean heat flow of 68±4 mW m-2; four measurements in the Mesozoic Luangwa and Zambezi Rifts range from 44 to 110 mW m-2 with a mean of 76±14 mW m-2. In comparing heat flow in east and southern Africa, we observe a common heat flow pattern of increasing heat flow away from the centers of the Archean cratons. This pattern suggests a fundamental difference in lithospheric thermal structure between the Archean cratons and the Proterozoic and early Paleozoic mobile belts which surround them. Superimposed on this common pattern are two regional variations in heat flow. Heat flow in the Tanzania Craton is lower by about 13 mW m-2 than in the Kalahari Craton, and in the Mozambique Belt in east Africa heat flow is somewhat lower than in the southern African mobile belts at similar distances from the Archean cratonic margin. The two regional variations can be explained in several ways, none of which can as yet be elevated to a preferred status: (1) by variations in crustal heat production, (2) by thin-skinned thrusting of the Mozambique Belt over the Tanzania Cratonic margin, (3) by lateral heat transfer from beneath the rift flanks into the rifts, or (4) by lower mantle heat flow beneath all of eastern Africa prior to the Cenozoic development of the East African rift system.
Hollow-Fiber Spacesuit Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

2013-01-01

The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.
Heat pipes for use in a magnetic field

DOEpatents

Werner, Richard W.; Hoffman, Myron A.

1983-01-01

A heat pipe configuration for use in a magnetic field environment of a fusion reactor. Heat pipes for operation in a magnetic field when liquid metal working fluids are used are optimized by flattening of the heat pipes having an unobstructed annulus which significantly reduces the adverse side region effect of the prior known cylindrically configured heat pipes. The flattened heat pipes operating in a magnetic field can remove 2--3 times the heat as a cylindrical heat pipe of the same cross sectional area.
Preliminary burn and impact tests of hybrid polymeric composites. [preventing graphite fiber release

NASA Technical Reports Server (NTRS)

Tompkins, S. S.; Brewer, W. D.

1978-01-01

Free graphite fibers released into the environment from resin matrix composite components, as a result of fire and/or explosion, pose a potential hazard to electrical equipment. An approach to prevent the fibers from becoming airborne is to use hybrid composite materials which retain the fibers at the burn site. Test results are presented for three hybrid composites that were exposed to a simulation of an aircraft fire and explosion. The hybrid systems consisted of 16 plies of graphite-epoxy with two plies of Kevlar-, S-glass-, or boron-epoxy on each face. Two different test environments were used. In one environment, specimens were heated by convection only, and then impacted by a falling mass. In the other environment, specimens were heated by convection and by radiation, but were not impacted. The convective heat flux was about 100-120 kW/m in both environments and the radiative flux was about 110 kW/sq m.
Europa, tidally heated oceans, and habitable zones around giant planets

NASA Astrophysics Data System (ADS)

Reynolds, R. T.; McKay, C. P.; Kasting, J. F.

Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. Europa could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such a case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of eons and in which life could perhaps evolve. A zone around a giant planet is defined in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In this solar system, this radiatively-heated habitable zone contains the earth.
Europa, tidally heated oceans, and habitable zones around giant planets

NASA Technical Reports Server (NTRS)

Reynolds, Ray T.; Mckay, Christopher P.; Kasting, James F.

1987-01-01

Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. Europa could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such a case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of eons and in which life could perhaps evolve. A zone around a giant planet is defined in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In this solar system, this radiatively-heated habitable zone contains the earth.
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.

Delta Clipper-Experimental In-Ground Effect on Base-Heating Environment

NASA Technical Reports Server (NTRS)

Wang, Ten-See

1998-01-01

A quasitransient in-ground effect method is developed to study the effect of vertical landing on a launch vehicle base-heating environment. This computational methodology is based on a three-dimensional, pressure-based, viscous flow, chemically reacting, computational fluid dynamics formulation. Important in-ground base-flow physics such as the fountain-jet formation, plume growth, air entrainment, and plume afterburning are captured with the present methodology. Convective and radiative base-heat fluxes are computed for comparison with those of a flight test. The influence of the laminar Prandtl number on the convective heat flux is included in this study. A radiative direction-dependency test is conducted using both the discrete ordinate and finite volume methods. Treatment of the plume afterburning is found to be very important for accurate prediction of the base-heat fluxes. Convective and radiative base-heat fluxes predicted by the model using a finite rate chemistry option compared reasonably well with flight-test data.
A study of leeside flow field heat transfer on Shuttle Orbiter configuration

NASA Technical Reports Server (NTRS)

Baranowski, L. C.; Kipp, H. W.

1984-01-01

A coupled inviscid and viscous theoretical solution of the flow about the entire configuration is the desirable and comprehensive approach to defining thermal environments about the space shuttle orbiter. Simplified methods for predicting entry heating on leeside surfaces of the orbiter are considered. Wind tunnel heat transfer and oil flow data at Mach 6 and 10 and Reynolds numbers ranging from 500,000 to 73 million were used to develop correlations for the wing upper surface and the top surface of the fuselage. These correlations were extrapolated to flight Reynolds number and compared with heating data obtained during the shuttle STS-2 reentry. Efforts directed toward the wing leeside surface resulted in an approach which generally agreed with the flight data. Heating predictions for the upper fuselage were less successful due to the extreme complexity of local flow interactions and the associated heating environment.
Aerodynamic heating environment definition/thermal protection system selection for the HL-20

NASA Astrophysics Data System (ADS)

Wurster, K. E.; Stone, H. W.

1993-09-01

Definition of the aerothermal environment is critical to any vehicle such as the HL-20 Personnel Launch System that operates within the hypersonic flight regime. Selection of an appropriate thermal protection system design is highly dependent on the accuracy of the heating-environment prediction. It is demonstrated that the entry environment determines the thermal protection system design for this vehicle. The methods used to predict the thermal environment for the HL-20 Personnel Launch System vehicle are described. Comparisons of the engineering solutions with computational fluid dynamic predictions, as well as wind-tunnel test results, show good agreement. The aeroheating predictions over several critical regions of the vehicle, including the stagnation areas of the nose and leading edges, windward centerline and wing surfaces, and leeward surfaces, are discussed. Results of predictions based on the engineering methods found within the MINIVER aerodynamic heating code are used in conjunction with the results of the extensive wind-tunnel tests on this configuration to define a flight thermal environment. Finally, the selection of the thermal protection system based on these predictions and current technology is described.
Liquid Rocket Booster (LRB) for the Space Transportation System (STS) systems study. Appendix B: Liquid rocket booster acoustic and thermal environments

NASA Technical Reports Server (NTRS)

1989-01-01

The ascent thermal environment and propulsion acoustic sources for the Martin-Marietta Corporation designed Liquid Rocket Boosters (LRB) to be used with the Space Shuttle Orbiter and External Tank are described. Two designs were proposed: one using a pump-fed propulsion system and the other using a pressure-fed propulsion system. Both designs use LOX/RP-1 propellants, but differences in performance of the two propulsion systems produce significant differences in the proposed stage geometries, exhaust plumes, and resulting environments. The general characteristics of the two designs which are significant for environmental predictions are described. The methods of analysis and predictions for environments in acoustics, aerodynamic heating, and base heating (from exhaust plume effects) are also described. The acoustic section will compare the proposed exhaust plumes with the current SRB from the standpoint of acoustics and ignition overpressure. The sections on thermal environments will provide details of the LRB heating rates and indications of possible changes in the Orbiter and ET environments as a result of the change from SRBs to LRBs.
Integrated Physiological Mechanisms of Exercise Performance, Adaptation, and Maladaptation to Heat Stress

DTIC Science & Technology

2011-10-01

performance. We discuss novel systemic (heat acclimation) and cellular ( acquired thermal tolerance) adaptations that improve performance in hot and...cellular ( acquired thermal tolerance) adaptations that improve perfor- mance in hot and temperate environments and protect organs from heat stroke as...performance; (iii) newly identified adaptations associated with heat accli- mation/ acquired thermal tolerance that impact exercise-heat tolerance; (iv
Heat illness and death among workers - United States, 2012-2013.

PubMed

Arbury, Sheila; Jacklitsch, Brenda; Farquah, Opeyemi; Hodgson, Michael; Lamson, Glenn; Martin, Heather; Profitt, Audrey

2014-08-08

Exposure to heat and hot environments puts workers at risk for heat stress, which can result in heat illnesses and death. This report describes findings from a review of 2012‒2013 Occupational Safety and Health Administration (OSHA) federal enforcement cases (i.e., inspections) resulting in citations under paragraph 5(a)(1), the "general duty clause" of the Occupational Safety and Health Act of 1970. That clause requires that each employer "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees". Because OSHA has not issued a heat standard, it must use 5(a)(1) citations in cases of heat illness or death to enforce employers' obligations to provide a safe and healthy workplace. During the 2-year period reviewed, 20 cases of heat illness or death were cited for federal enforcement under paragraph 5(a)(1) among 18 private employers and two federal agencies. In 13 cases, a worker died from heat exposure, and in seven cases, two or more employees experienced symptoms of heat illness. Most of the affected employees worked outdoors, and all performed heavy or moderate work, as defined by the American Conference of Governmental Industrial Hygienists. Nine of the deaths occurred in the first 3 days of working on the job, four of them occurring on the worker's first day. Heat illness prevention programs at these workplaces were found to be incomplete or absent, and no provision was made for the acclimatization of new workers. Acclimatization is the result of beneficial physiologic adaptations (e.g., increased sweating efficiency and stabilization of circulation) that occur after gradually increased exposure to heat or a hot environment. Whenever a potential exists for workers to be exposed to heat or hot environments, employers should implement heat illness prevention programs (including acclimatization requirements) at their workplaces.
Heat-activated Plasmonic Chemical Sensors for Harsh Environments

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

Carpenter, Michael; Oh, Sang-Hyun

2015-12-01

A passive plasmonics based chemical sensing system to be used in harsh operating environments was investigated and developed within this program. The initial proposed technology was based on combining technologies developed at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering (CNSE) and at the University of Minnesota (UM). Specifically, a passive wireless technique developed at UM was to utilize a heat-activated plasmonic design to passively harvest the thermal energy from within a combustion emission stream and convert this into a narrowly focused light source. This plasmonic device was based on a bullseye design patterned into a gold filmmore » using focused ion beam methods (FIB). Critical to the design was the use of thermal stabilizing under and overlayers surrounding the gold film. These stabilizing layers were based on both atomic layer deposited films as well as metal laminate layers developed by United Technologies Aerospace Systems (UTAS). While the bullseye design was never able to be thermally stabilized for operating temperatures of 500oC or higher, an alternative energy harvesting design was developed by CNSE within this program. With this new development, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The method was further improved by patterning rods which harvested energy in the near infrared, which led to a factor of 10 decrease in data acquisition times as well as demonstrated selectivity with a reduced wavelength data set. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis and wavelength down selection offers a novel path towards simplification and integration of plasmonic-based sensing methods using selected wavelengths rather than a full spectral analysis. Integration efforts were designed and modeled for thermal and mass transport considerations by UTAS which led to the 3D printing of scaled models that would serve as the housing for the alternative energy harvesting plasmonic chemical sensor design developed by CNSE.« less
Aerothermodynamic Design of the Mars Science Laboratory Heatshield

NASA Technical Reports Server (NTRS)

Edquist, Karl T.; Dyakonov, Artem A.; Wright, Michael J.; Tang, Chun Y.

2009-01-01

Aerothermodynamic design environments are presented for the Mars Science Laboratory entry capsule heatshield. The design conditions are based on Navier-Stokes flowfield simulations on shallow (maximum total heat load) and steep (maximum heat flux, shear stress, and pressure) entry trajectories from a 2009 launch. Boundary layer transition is expected prior to peak heat flux, a first for Mars entry, and the heatshield environments were defined for a fully-turbulent heat pulse. The effects of distributed surface roughness on turbulent heat flux and shear stress peaks are included using empirical correlations. Additional biases and uncertainties are based on computational model comparisons with experimental data and sensitivity studies. The peak design conditions are 197 W/sq cm for heat flux, 471 Pa for shear stress, 0.371 Earth atm for pressure, and 5477 J/sq cm for total heat load. Time-varying conditions at fixed heatshield locations were generated for thermal protection system analysis and flight instrumentation development. Finally, the aerothermodynamic effects of delaying launch until 2011 are previewed.
Spacecraft Thermal Control

NASA Technical Reports Server (NTRS)

Birur, Gajanana C.; Siebes, Georg; Swanson, Theodore D.; Powers, Edward I. (Technical Monitor)

2001-01-01

Thermal control of the spacecraft is typically achieved by removing heat from the spacecraft parts that tend to overheat and adding heat to the parts that tend get too cold. The equipment on the spacecraft can get very hot if it is exposed to the sun or have internal heat generation. The pans also can get very cold if they are exposed to the cold of deep space. The spacecraft and instruments must be designed to achieve proper thermal balance. The combination of the spacecraft's external thermal environment, its internal heat generation (i.e., waste heat from the operation of electrical equipment), and radiative heat rejection will determine this thermal balance. It should also be noted that this is seldom a static situation, external environmental influences and internal heat generation are normally dynamic variables which change with time. Topics discussed include thermal control system components, spacecraft mission categories, spacecraft thermal requirements, space thermal environments, thermal control hardware, launch and flight operations, advanced technologies for future spacecraft,
Body heat storage during intermittent work in hot-dry and warm-wet environments.

PubMed

Stapleton, Jill M; Wright, Heather E; Hardcastle, Stephen G; Kenny, Glen P

2012-10-01

We examined heat balance using an American Conference of Governmental Industrial Hygienists threshold limit value allocated exercise protocol in hot-dry (HD; 46 °C, 10% relative humidity (RH)) and warm-wet (WW; 33 °C, 60% RH) environments of equivalent WBGT (29 °C) for different clothing ensembles. Whole-body heat exchange and changes in body heat content (ΔH(b)) were measured using simultaneous direct whole-body and indirect calorimetry. Eight males performed six 15-min cycling periods at a constant rate of metabolic heat production (360 W) interspersed by 5-min rest periods for six experimental trials: HD and WW environments for a seminude control (CON), modified work uniform (MWU, moisture permeable top and work pants), and standard work uniform (SWU, work coveralls and cotton undergarments). Whole-body evaporative and dry heat exchange, rectal temperature (T(re)), and heart rate were measured continuously. The cumulative ΔH(b) during the 2 h intermittent exercise protocol was similar between HD and WW environments for each of the clothing ensembles (CON, 387 ± 55 vs. 435 ± 49 kJ; MWU, 485 ± 58 vs. 531 ± 61 kJ; SWU, 585 ± 74 vs. 660 ± 54 kJ, respectively). Similarly, no differences in T(re) (CON, 37.67 ± 0.07 vs. 37.48 ± 0.08 °C; MWU, 37.73 ± 0.08 vs. 37.53 ± 0.09 °C; SWU, 38.01 ± 0.09 vs. 37.94 ± 0.05 °C) or heat rate (CON, 93 ± 3 vs. 84 ± 3 beats·min⁻¹; MWU, 102 ± 5 vs. 95 ± 9 beats·min⁻¹; SWU, 119 ± 8 vs. 110 ± 9 beats·min⁻¹) were observed at the end of the 2 h intermittent exercise protocol in HD vs. WW environments, respectively. We showed similar levels of thermal and cardiovascular strain for intermittent work performed in high heat stress conditions of varying environmental conditions but similar WBGT.
Latitudinal patterns of leaf N, P stoichiometry and nutrient resorption of Metasequoia glyptostroboides along the eastern coastline of China.

PubMed

Zhang, Hui; Guo, Weihong; Yu, Mukui; Wang, G Geoff; Wu, Tonggui

2018-03-15

Latitudinal patterns of leaf stoichiometry and nutrient resorption were not consistent among published studies, likely due to confounding effects from taxonomy (e.g., plant distribution and community composition), and environment, which is also influenced by altitude and longitude. Thus, the latitudinal patterns and environmental mechanism could be best revealed by testing a given species along a latitude gradient with similar altitude and longitude. We determined nitrogen (N) and phosphorus (P) concentrations of green (leaf) and senesced leaves (litter) from eight Metasequoia glyptostroboides forests along the eastern coastline of China, with similar altitude and longitude. Leaf N, P concentrations increased along latitude, mainly driven by mean annual temperature (MAT), mean annual precipitation (MAP), annual evaporation (AE), aridity index (AI), and annual total solar radiation (ATSR); While leaf N:P ratio was stable with no latitudinal pattern. Nitrogen resorption efficiency (NRE) increased along latitude, and was also mainly influenced by MAT, MAP, AE, and AI. Phosphorus resorption efficiency (PRE) first increased and then decreased with latitude, which was impacted by soil available P. These results indicated that only climate (such as heat, water, and light) controlled the shift in leaf stoichiometry and NRE, while soil nutrient was likely responsible for the shift in PRE along eastern China. Our findings also suggested that leaf N, P stoichiometry and NRE displayed similar latitudinal patterns at regional scale when studied for a given species (this study) or multi-species (previous studies). Copyright © 2017. Published by Elsevier B.V.
Contrasting Heat Budget Dynamics During Two La Niña Marine Heat Wave Events Along Northwestern Australia

NASA Astrophysics Data System (ADS)

Xu, Jiangtao; Lowe, Ryan J.; Ivey, Gregory N.; Jones, Nicole L.; Zhang, Zhenling

2018-02-01

Two marine heat wave events along Western Australia (WA) during the alternate austral summer periods of 2010/2011 and 2012/2013, both linked to La Niña conditions, severely impacted marine ecosystems over more than 12° of latitude, which included the unprecedented bleaching of many coral reefs. Although these two heat waves were forced by similar large-scale climate drivers, the warming patterns differed substantially between events. The central coast of WA (south of 22°S) experienced greater warming in 2010/2011, whereas the northwestern coast of WA experienced greater warming in 2012/2013. To investigate how oceanic and atmospheric heat exchange processes drove these different spatial patterns, an analysis of the ocean heat budget was conducted by integrating remote sensing observations, in situ mooring data, and a high-resolution (˜1 km) ocean circulation model (Regional Ocean Modeling System). The results revealed substantial spatial differences in the relative contributions made by heat advection and air-sea heat exchange between the two heat wave events. During 2010/2011, anomalous warming driven by heat advection was present throughout the region but was much stronger south of 22°S where the poleward-flowing Leeuwin Current strengthens. During 2012/2013, air-sea heat exchange had a much more positive (warming) influence on sea surface temperatures (especially in the northwest), and when combined with a more positive contribution of heat advection in the north, this can explain the regional differences in warming between these two La Niña-associated marine heat wave events.
Atmostpheric simulations of extreme surface heating episodes on simple hills

Treesearch

W.E. Heilman

1992-01-01

A two-dimensional nonhydrostatic atmospheric model was used to simulate the circulation patterns (wind and vorticity) and turbulence energy fields associated with lines of extreme surface heating on simple two-dimensional hills. Heating-line locations and ambient crossflow conditions were varied to qualitatively determine the impact of terrain geometry on the...
Characterization of tea polyphenols as potential environment-friendly fire retardants

NASA Astrophysics Data System (ADS)

Yao, Fengqi; Zhai, Chunjie; Wang, Haihui; Tao, Junjun

2018-02-01

In this work we investigated the oxidation properties of tea polyphenols and their potential as the fire retardants. Two types of tea polyphenols were adopted, which were extracted from red tea and green tea leaves, respectively. Their macroscopic performance during pyrolysis and oxidation at elevated temperatures were examined by using a heating furnace. Mass change, heat evolution and gas products of tea polyphenols during heating in air were also monitored by using a thermo-gravimetric analyzer (TGA) integrated with a differential scanning calorimeter (DSC) in conjunction with online Fourier Transform Infrared Spectroscopy (FTIR) and mass spectroscopy (MS). A tea polyphenol sample first becomes a brown semi-fluid after heating, and gradually turns into highly-porous black chars with significantly expanded volume. By raising the temperature to ∼550 °C at a rate of 10 °C/min, the mass of a sample reduces by nearly 70% to form a large quantity of inert gases that are mainly composed of H2O and CO2. It was found that the aerial oxidation products of tea polyphenols in the solid phase possess good heat insulation property; meanwhile, the substantial release of a lot of water and its evaporation during oxidation of tea polyphenols removes a large amount of heat from a sample located in a heating environment. The heat insulation of tea polyphenols may withstand up to 550 °C. The present work confirms tea polyphenols as potential superior and environment-friendly fire retardants.
Mantle heat flow and thermal structure of the northern block of Southern Granulite Terrain, India

NASA Astrophysics Data System (ADS)

Manglik, Ajay

2006-07-01

Continental shield regions are normally characterized by low-to-moderate mantle heat flow. Archaean Dharwar craton of the Indian continental shield also follows the similar global pattern. However, some recent studies have inferred significantly higher mantle heat flow for the Proterozoic northern block of Southern Granulite Terrain (SGT) in the immediate vicinity of the Dharwar craton by assuming that the radiogenic elements depleted exposed granulites constitute the 45-km-thick crust. In this study, we use four-layered model of the crustal structure revealed by integrated geophysical studies along a geo-transect in this region to estimate the mantle heat flow. The results indicate that: (i) the mantle heat flow of the northern block of SGT is 17 ± 2 mW/m 2, supporting the global pattern, and (ii) the lateral variability of 10-12 mW/m 2 in the surface heat flow within the block is of crustal origin. In terms of temperature, the Moho beneath the eastern Salem-Namakkal region appears to be at 80-100 °C higher temperature than that beneath the western Avinashi region.
Performance Analysis of Thermoelectric Modules Consisting of Square Truncated Pyramid Elements Under Constant Heat Flux

NASA Astrophysics Data System (ADS)

Oki, Sae; Natsui, Shungo; Suzuki, Ryosuke O.

2018-01-01

System design of a thermoelectric (TE) power generation module is pursued in order to improve the TE performance. Square truncated pyramid shaped P-N pairs of TE elements are connected electronically in series in the open space between two flat insulator boards. The performance of the TE module consisting of 2-paired elements is numerically simulated using commercial software and original TE programs. Assuming that the heat radiating into the hot surface is regulated, i.e., the amount of heat from the hot surface to the cold one is steadily constant, as it happens for solar radiation heating, the performance is significantly improved by changing the shape and the alignment pattern of the elements. When the angle θ between the edge and the base is smaller than 72°, and when the cold surface is kept at a constant temperature, two patterns in particular, amongst the 17 studied, show the largest TE power and efficiency. In comparison to other geometries, the smarter square truncated pyramid shape can provide higher performance using a large cold bath and constant heat transfer by heat radiation.
Performance Analysis of Thermoelectric Modules Consisting of Square Truncated Pyramid Elements Under Constant Heat Flux

NASA Astrophysics Data System (ADS)

Oki, Sae; Natsui, Shungo; Suzuki, Ryosuke O.

2018-06-01

System design of a thermoelectric (TE) power generation module is pursued in order to improve the TE performance. Square truncated pyramid shaped P-N pairs of TE elements are connected electronically in series in the open space between two flat insulator boards. The performance of the TE module consisting of 2-paired elements is numerically simulated using commercial software and original TE programs. Assuming that the heat radiating into the hot surface is regulated, i.e., the amount of heat from the hot surface to the cold one is steadily constant, as it happens for solar radiation heating, the performance is significantly improved by changing the shape and the alignment pattern of the elements. When the angle θ between the edge and the base is smaller than 72°, and when the cold surface is kept at a constant temperature, two patterns in particular, amongst the 17 studied, show the largest TE power and efficiency. In comparison to other geometries, the smarter square truncated pyramid shape can provide higher performance using a large cold bath and constant heat transfer by heat radiation.
Pressure Ratio to Thermal Environments

NASA Technical Reports Server (NTRS)

Lopez, Pedro; Wang, Winston

2012-01-01

A pressure ratio to thermal environments (PRatTlE.pl) program is a Perl language code that estimates heating at requested body point locations by scaling the heating at a reference location times a pressure ratio factor. The pressure ratio factor is the ratio of the local pressure at the reference point and the requested point from CFD (computational fluid dynamics) solutions. This innovation provides pressure ratio-based thermal environments in an automated and traceable method. Previously, the pressure ratio methodology was implemented via a Microsoft Excel spreadsheet and macro scripts. PRatTlE is able to calculate heating environments for 150 body points in less than two minutes. PRatTlE is coded in Perl programming language, is command-line-driven, and has been successfully executed on both the HP and Linux platforms. It supports multiple concurrent runs. PRatTlE contains error trapping and input file format verification, which allows clear visibility into the input data structure and intermediate calculations.
Experimental Study on Flow Boiling of Carbon Dioxide in a Horizontal Microfin Tube

NASA Astrophysics Data System (ADS)

Kuwahara, Ken; Ikeda, Soshi; Koyama, Shigeru

This paper deals with the experimental study on flow boiling heat transfer of carbon dioxide in a micro-fin tube. The geometrical parameters of micro-fin tube used in this study are 6.07 mm in outer diameter, 5.24 mm in average inner diameter, 0.256 mm in fin height, 20.4 in helix angle, 52 in number of grooves and 2.35 in area expansion ratio. Flow patterns and heat transfer coefficients were measured at 3-5 MPa in pressure, 300-540 kg/(m2s) in mass velocity and -5 to 15 °C in CO2 temperature. Flow patterns of wavy flow, slug flow and annular flow were observed. The measured heat transfer coefficients of micro-fin tube were 10-40 kW/(m2K). Heat transfer coefficients were strongly influenced by pressure.
SPATIAL APPROACH TO PLANNING THE PHYSICAL ENVIRONMENT.

ERIC Educational Resources Information Center

BELLOMY, CLEON C.; CAUDILL, WILLIAM W.

THE PURPOSE OF THIS REPORT DEFINES THE SPATIAL APPROACH TO PLANNING THE PHYSICAL ENVIRONMENT AND SUGGESTS A MORE NATURAL APPROACH TO A LESS RESTRICTED ARCHITECTURE. ONE OF THE TWO BASIC ARCHITECTURAL ELEMENTS IN THE SPATIAL CONCEPT IS THE HORIZONTAL SCREEN WHICH KEEPS THE SUN AND RAIN OFF, LETS IN LIGHT, KEEPS OUT SUN HEAT, RETAINS ROOM HEAT, AND…

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart FFFF of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National...
40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart FFFF of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission...
40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart FFFF of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission...
40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart FFFF of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National...
40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart FFFF of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National...
Heat Shield for Extreme Entry Environment Technology (HEEET)

NASA Technical Reports Server (NTRS)

Venkatapathy, Ethiraj

2017-01-01

The Heat Shield for Extreme Entry Environment Technology (HEEET) project seeks to mature a game changing Woven Thermal Protection System (TPS) technology to enable in situ robotic science missions recommended by the NASA Research Council Planetary Science Decadal Survey committee. Recommended science missions include Venus probes and landers; Saturn and Uranus probes; and high-speed sample return missions.
Energy and Environment Guide to Action - Chapter 6: Policy Considerations for Combined Heat and Power

EPA Pesticide Factsheets

CHP, also known as cogeneration, is the simultaneous production of electricity and heat from a single fuel source. Read more about recommendations for designing, implementing, and evaluating combined heat and power.
Targeted Prostate Thermal Therapy with Catheter-Based Ultrasound Devices and MR Thermal Monitoring

NASA Astrophysics Data System (ADS)

Diederich, Chris; Ross, Anthony; Kinsey, Adam; Nau, Will H.; Rieke, Viola; Butts Pauly, Kim; Sommer, Graham

2006-05-01

Catheter-based ultrasound devices have significant advantages for thermal therapy procedures, including potential for precise spatial and dynamic control of heating patterns to conform to targeted volumes. Interstitial and transurethral ultrasound applicators, with associated treatment strategies, were developed for thermal ablation of prostate combined with MR thermal monitoring. Four types of multielement transurethral applicators were devised, each with different levels of selectivity and intended therapeutic goals: sectored tubular transducer devices with fixed directional heating patterns; planar and lightly focused curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Similarly, interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with fixed directional heating patterns (e.g., 180 deg.). In vivo experiments in canine prostate (n=15) under MR temperature imaging were used to evaluate the heating technology and develop treatment strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature contours and thermal dose in multiple slices through the target volume. Sectored transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. The curvilinear applicator produces distinct 2-3 mm wide lesions, and with sequential rotation and modulated dwell time can precisely conform thermal ablation to selected areas or the entire prostate gland. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with directional devices can be used to effectively ablate the posterior peripheral zone of the gland while protecting the rectum. An implant with multi-sectored interstitial devices can effectively control the angular heating pattern without applicator rotation. The MR derived 52 °C and lethal thermal dose contours (t43=240 min) allowed for real-time control of the applicators and effectively defined the extent of thermal damage. Catheter-based ultrasound devices, combined with MR thermal monitoring, can produce relatively fast and precise thermal ablation of prostate, with potential for treatment of cancer or BPH.
Comparative assessment of heat stress induced changes in carcass traits, plasma leptin profile and skeletal muscle myostatin and HSP70 gene expression patterns between indigenous Osmanabadi and Salem Black goat breeds.

PubMed

Archana, P R; Sejian, V; Ruban, Wilfred; Bagath, M; Krishnan, G; Aleena, J; Manjunathareddy, G B; Beena, V; Bhatta, Raghavendra

2018-07-01

The primary objective of the study was to compare the impact of heat stress on meat production characteristics of Osmanabadi and Salem Black breed goats based on changes in carcass characteristics, meat quality attributes, plasma leptin concentration, skeletal muscle myostatin and heat shock protein 70 (HSP70) gene expression patterns. The goats were randomly distributed into four groups: OSC (n = 6; Osmanabadi Control), OSHS (n = 6; Osmanabadi Heat Stress), SBC (n = 6; Salem Black Control) and SBHS (n = 6; Salem Black Heat Stress). The animals were slaughtered at the end of the study and their meat characteristics were assessed. This study established the impact of heat stress on a wide variety of carcass and meat quality characteristics in OS and SB goat breeds. The results from the study also provided some crucial evidence for a better resilience capacity of Salem Black breed as compared to Osmanabadi goats in maintaining the meat production during heat stress. The study also established plasma leptin and HSP70 genes to be the ideal biomarkers to reflect the impact of heat stress on meat characteristics in indigenous goats. Copyright © 2018 Elsevier Ltd. All rights reserved.
Startup of a frozen heat pipe in one-g and micro-g environments - A proposed shuttle flight experiment

NASA Technical Reports Server (NTRS)

Ochterbeck, J. M.; Peterson, G. P.

1991-01-01

An attempt is made to determine how a heat pipe freezes under various low load and/or no load conditions in both one-g and micro-g environments. Also of interest are the mechanisms that can be used to restart the heat pipe after freezing has occurred. Particular attention is given to step function power reductions and the resulting distribution of the working fluid after freezing has occurred and the effect of noncondensible gases on the frozen configuration and the restart characteristics.
Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, T.T.; Blake, R.D.

1985-04-03

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.
Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, Thomas T.; Blake, Rodger D.

1987-01-01

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.
40 CFR 97.76 - Additional requirements to provide heat input data.

Code of Federal Regulations, 2010 CFR

2010-07-01

... heat input data. 97.76 Section 97.76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Monitoring and Reporting § 97.76 Additional requirements to provide heat input data. The owner or operator of... a flow system shall also monitor and report heat input rate at the unit level using the procedures...
40 CFR 97.76 - Additional requirements to provide heat input data.

Code of Federal Regulations, 2011 CFR

2011-07-01

... heat input data. 97.76 Section 97.76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Monitoring and Reporting § 97.76 Additional requirements to provide heat input data. The owner or operator of... a flow system shall also monitor and report heat input rate at the unit level using the procedures...
40 CFR 97.76 - Additional requirements to provide heat input data.

Code of Federal Regulations, 2013 CFR

2013-07-01

... heat input data. 97.76 Section 97.76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Monitoring and Reporting § 97.76 Additional requirements to provide heat input data. The owner or operator of... a flow system shall also monitor and report heat input rate at the unit level using the procedures...
40 CFR 97.76 - Additional requirements to provide heat input data.

Code of Federal Regulations, 2014 CFR

2014-07-01

... heat input data. 97.76 Section 97.76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Monitoring and Reporting § 97.76 Additional requirements to provide heat input data. The owner or operator of... a flow system shall also monitor and report heat input rate at the unit level using the procedures...
40 CFR 97.76 - Additional requirements to provide heat input data.

Code of Federal Regulations, 2012 CFR

2012-07-01

... heat input data. 97.76 Section 97.76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Monitoring and Reporting § 97.76 Additional requirements to provide heat input data. The owner or operator of... a flow system shall also monitor and report heat input rate at the unit level using the procedures...
40 CFR 63.1085 - What are the general requirements for heat exchange systems?

Code of Federal Regulations, 2011 CFR

2011-07-01

... heat exchange systems? 63.1085 Section 63.1085 Protection of Environment ENVIRONMENTAL PROTECTION... Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085 What are the general requirements for heat exchange systems? Unless you meet one of the requirements for exemptions in § 63.1084...
40 CFR 63.1085 - What are the general requirements for heat exchange systems?

Code of Federal Regulations, 2013 CFR

2013-07-01

... heat exchange systems? 63.1085 Section 63.1085 Protection of Environment ENVIRONMENTAL PROTECTION... Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085 What are the general requirements for heat exchange systems? Unless you meet one of the requirements for exemptions in § 63.1084...
40 CFR 63.1085 - What are the general requirements for heat exchange systems?

Code of Federal Regulations, 2014 CFR

2014-07-01

... heat exchange systems? 63.1085 Section 63.1085 Protection of Environment ENVIRONMENTAL PROTECTION... Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085 What are the general requirements for heat exchange systems? Unless you meet one of the requirements for exemptions in § 63.1084...

40 CFR 63.1085 - What are the general requirements for heat exchange systems?

Code of Federal Regulations, 2012 CFR

2012-07-01

... heat exchange systems? 63.1085 Section 63.1085 Protection of Environment ENVIRONMENTAL PROTECTION... Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085 What are the general requirements for heat exchange systems? Unless you meet one of the requirements for exemptions in § 63.1084...
Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports.

PubMed

Périard, J D; Racinais, S; Sawka, M N

2015-06-01

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm-hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Exercise in the Heat. II. Critical Concepts in Rehydration, Exertional Heat Illnesses, and Maximizing Athletic Performance

PubMed Central

Casa, Douglas J.

1999-01-01

Objective: To acquaint athletic trainers with the numerous interrelated components that must be considered when assisting athletes who exercise in hot environments. Useful guidelines to maximize performance and minimize detrimental health consequences are presented. Data Sources: The databases MEDLINE and SPORT Discus were searched from 1980 to 1999, with the terms. “body cooling,” “dehydration,” “exercise,” “heat illnesses,” “heat,” “fluid replacement,” “acclimatization,” “hydration,” “rehydration,” “performance,” and “intravenous,” among others. Data Synthesis: This paper provides an in-depth look at issues regarding physiologic and performance considerations related to rehydration, strategies to maximize rehydration, modes of rehydration, health consequences of exercise in the heat, heat acclimatization, body cooling techniques, and practice and competition modifications. Conclusions/Recommendations: Athletic trainers have a responsibility to ensure that athletes who exercise in hot environments are prepared to do so in an optimal manner and to act properly to avoid the potentially harmful heat illnesses that can result from exercise in the heat. PMID:16558573
SRB ascent aerodynamic heating design criteria reduction study, volume 1

NASA Technical Reports Server (NTRS)

Crain, W. K.; Frost, C. L.; Engel, C. D.

1989-01-01

An independent set of solid rocket booster (SRB) convective ascent design environments were produced which would serve as a check on the Rockwell IVBC-3 environments used to design the ascent phase of flight. In addition, support was provided for lowering the design environments such that Thermal Protection System (TPS), based on conservative estimates, could be removed leading to a reduction in SRB refurbishment time and cost. Ascent convective heating rates and loads were generated at locations in the SRB where lowering the thermal environment would impact the TPS design. The ascent thermal environments are documented along with the wind tunnel/flight test data base used as well as the trajectory and environment generation methodology. Methodology, as well as, environment summaries compared to the 1980 Design and Rockwell IVBC-3 Design Environment are presented in this volume, 1.
Heat flow in eastern Egypt - The thermal signature of a continental breakup

NASA Technical Reports Server (NTRS)

Morgan, P.; Boulos, F. K.; Hennin, S. F.; El-Sherif, A. A.; El-Sayed, A. A.

1985-01-01

It is noted that the Red Sea is a modern example of continental fragmentation and incipient ocean formation. A consistent pattern of high heat flow in the Red Sea margins and coastal zone, including Precambrian terrane up to at least 30 km from the Red Sea, has emerged from the existing data. It is noted that this pattern has important implications for the mode and mechanism of Red Sea opening. High heat flow in the Red Sea shelf requires either a high extension of the crust in this zone (probably with major basic magmatic activity) or young oceanic crust beneath this zone. High heat flow in the coastal thermal anomaly zone may be caused by lateral conduction from the offshore lithosphere and/or from high mantle heat flow. It is suggested that new oceanic crust and highly extended continental crust would be essentially indistinguishable with the available data in the Red Sea margins, and are for many purposes essentially identical.
Simulation of interior ballistics flows in a shock tube

NASA Astrophysics Data System (ADS)

Seiler, F.

1983-07-01

The flow in front of and behind a projectile was investigated in a interior ballistics shock tube simulator. Flow patterns and heat flow were examined for flows with and without gas leakage. The boundary layers behind the piston can clearly be shown by differential interferograms. The dependence of the heat flow into the measuring tube wall on the base form is smaller than the signal perturbations. Flow patterns show no appreciable effect of gas leakage on the flow behind the piston; strong flow effects arise in front of the piston. The same effects are shown by heat flow measurements. In case of gas leakage heat flows into the tube wall before the piston reaches the wall. In the slit between piston and wall a maximum heat flow is found. High temperature gradients, due to the fact that hot gases come closer to the tube wall than in the boundary layer flow behind the piston, lead to high thermal loading of the wall materials which can cause cracks.
Unexpected Patterns in Snow and Dirt

ERIC Educational Resources Information Center

Ackerson, Bruce J.

2018-01-01

For more than 30 years, Albert A. Bartlett published "Thermal patterns in the snow" in this journal. These are patterns produced by heat sources underneath the snow. Bartlett's articles encouraged me to pay attention to patterns in snow and to understanding them. At winter's end the last snow becomes dirty and is heaped into piles. This…
Heat strain in cold.

PubMed

Rintamäki, Hannu; Rissanen, Sirkka

2006-07-01

In spite of increased environmental cold stress, heat strain is possible also in a cold environment. The body heat balance depends on three factors: environmental thermal conditions, metabolic heat production and thermal insulation of clothing and other protective garments. As physical exercise may increase metabolic heat production from rest values by ten times or even more, the required thermal insulation of clothing may vary accordingly. However, in most outdoor work, and often in indoor cold work, too, the thermal insulation of clothing is impractical, difficult or impossible to adjust according to the changes in physical activity. This is especially true with whole body covering garments like chemical protective clothing. As a result of this imbalance, heat strain may develop. In cold all the signs of heat strain (core temperature above 38 degrees C, warm or hot thermal sensations, increased cutaneous circulation and sweating) may not be present at the same time. Heat strain in cold may be whole body heat strain or related only to torso or core temperature. Together with heat strain in torso or body core, there can be at the same time even cold strain in peripheral parts and/or superficial layers of the body. In cold environment both the preservation of insulation and facilitation of heat loss are important. Development of clothing design is still needed to allow easy adjustments of thermal insulation.
40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... standard conditions of 68 °F and 1 atmosphere. b MHC = molar heat content (higher heating value basis), Btu...
40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... standard conditions of 68 °F and 1 atmosphere. b MHC = molar heat content (higher heating value basis), Btu...
Temperature Observation Time and Type Influence Estimates of Heat-Related Mortality in Seven U.S. Cities

PubMed Central

Davis, Robert E.; Hondula, David M.; Patel, Anjali P.

2015-01-01

Background: Extreme heat is a leading weather-related cause of mortality in the United States, but little guidance is available regarding how temperature variable selection impacts heat–mortality relationships. Objectives: We examined how the strength of the relationship between daily heat-related mortality and temperature varies as a function of temperature observation time, lag, and calculation method. Methods: Long time series of daily mortality counts and hourly temperature for seven U.S. cities with different climates were examined using a generalized additive model. The temperature effect was modeled separately for each hour of the day (with up to 3-day lags) along with different methods of calculating daily maximum, minimum, and mean temperature. We estimated the temperature effect on mortality for each variable by comparing the 99th versus 85th temperature percentiles, as determined from the annual time series. Results: In three northern cities (Boston, MA; Philadelphia, PA; and Seattle, WA) that appeared to have the greatest sensitivity to heat, hourly estimates were consistent with a diurnal pattern in the heat-mortality response, with strongest associations for afternoon or maximum temperature at lag 0 (day of death) or afternoon and evening of lag 1 (day before death). In warmer, southern cities, stronger associations were found with morning temperatures, but overall the relationships were weaker. The strongest temperature–mortality relationships were associated with maximum temperature, although mean temperature results were comparable. Conclusions: There were systematic and substantial differences in the association between temperature and mortality based on the time and type of temperature observation. Because the strongest hourly temperature–mortality relationships were not always found at times typically associated with daily maximum temperatures, temperature variables should be selected independently for each study location. In general, heat-mortality was more closely coupled to afternoon and maximum temperatures in most cities we examined, particularly those typically prone to heat-related mortality. Citation: Davis RE, Hondula DM, Patel AP. 2016. Temperature observation time and type influence estimates of heat-related mortality in seven U.S. cities. Environ Health Perspect 124:795–804; http://dx.doi.org/10.1289/ehp.1509946 PMID:26636734
Temperature responses in severely burned children during exercise in a hot environment.

PubMed

McEntire, Serina J; Chinkes, David L; Herndon, David N; Suman, Oscar E

2010-01-01

The authors have previously described thermoregulatory responses of severely burned children during submaximal exercise in a thermoneutral environment. However, the thermoregulatory response of burned children to exercise in the heat is not well understood and could have important safety implications for rehabilitation. Children (n = 10) with >40% TBSA burns and nonburned children (n = 10) performed a 30-minute bout of treadmill exercise at 75% of their peak aerobic power in a heated environment. Intestinal temperature, burned and unburned skin temperature, and heart rate were recorded pre-exercise, every 2 minutes during exercise, and during recovery. Three of the 10 burned children completed the exercise bout in the heat; however, all the nonburned children completed the 30-minute bout. One burned child reached a core body temperature >39 degrees C at minute 23. Burned children had significantly higher core body temperature through the first 12 minutes of exercise compared with nonburned children. However, nine of 10 (90%) burned children did not become hyperthermic during exercise in the heat. Specific to this study, hyperthermia did not typically occur in burned children, relative to nonburned children. Whether this is due to an intolerance to exercise in the heat or to an inability to generate sufficient heat during exercise needs to be explored further.
Geothermal properties and groundwater flow estimated with a three-dimensional geological model in a late Pleistocene terrace area, central Japan

NASA Astrophysics Data System (ADS)

Funabiki, A.; Takemura, T.; Hamamoto, S.; Komatsu, T.

2012-12-01

1. Introduction The ground source heat pump (GSHP) is a highly efficient and renewable energy technology for space heating and cooling, with benefits that include energy conservation and reductions in greenhouse gas emissions. One result of the huge Tohoku-oki earthquake and tsunami and the subsequent nuclear disasters is that GSHPs are receiving more attention from the media and they are being introduced by some local governments. Heat generated by underground GSHP installation, however, can pollute the geothermal environment or change groundwater flow patterns . In this study, we estimated possible effects from the use of GSHPs in the Tokyo area with a three-dimensional (3D) geological model. 2. Geological model The Tokyo Metropolitan Area is surrounded by the Late Pleistocene terraces called the Musashino uplands. The terrace surfaces are densely populated residential areas. One of these surfaces, the Shimosueyohi surface, formed along the Tama River during the last deglacial period. The CRE-NUCHS-1 core (Funabiki et al., 2011) was obtained from this surface, and the lithology, heat transfer coefficients, and chemical characteristics of the sediments were analyzed. In this study, we used borehole log data from a 5 km2 area surrounding the CRE-NUCHS-1 core site to create a 3D geological model. In this area, the Pleistocene Kazusa Group is overlain by terrace gravels and a volcanic ash layer called the Kanto Loam. The terrace gravels occur mainly beneath the Kanda, Kitazawa, and Karasuyama rivers , which flow parallel to the Tama River, whereas away from the rivers , the Kanto Loam directly overlies the Kazusa Group sediments. 3. Geothermal disturbance and groundwater flow Using the geological model, we calculated the heat transfer coefficients and groundwater flow velocities in the sediments. Within the thick terrace gravels, which are at relatively shallow depth (8-20 m), heat transfer coefficients were high and groundwater flow was relatively fast. The amount of disturbance of the geothermal environment and groundwater flow caused by the use of GSHPs, therefore, would depend on the thickness of these gravels. Reference Funabiki, A., Nagoya, K., Kaneki, A., Uemura, K., Kurihara, M., Obara, H., Goto, A., Chiba, T., Naya, T., Ueki, T., and Takemura, T. (2011) Sedimentary facies and physical properties of the sediment core CRE-NUCHS-1 in Setagaya district, Tokyo, central Japan. Abstracts, The 118th Annual Meeting of theGeological Society of Japan. Acknowledgement This work was supported by the Core Research for Evolutional Science and Technology (CREST) program of the Japan Science and Technology Agency (JST).
Degradation of ground ice in a changing climate: the potential impact of groundwater flow

NASA Astrophysics Data System (ADS)

de Grandpré, I.; Fortier, D.; Stephani, E.

2011-12-01

Climate changes affecting the North West portion of Canada alter the thermal state of the permafrost and promote ground ice degradation. Melting of ground ice leads to greater water flow into the ground and to significant hydraulic changes (i.e. drainage of peatland and lakes, triggering of thermokarst and new groundwater flow patterns). Road infrastructures built on permafrost are particularly sensitive to permafrost degradation. Road construction and maintenance induce heat flux into the ground by the increase of solar radiation absorption (comparing to natural ground), the increase of snow cover on side slopes, the infiltration of water in embankment material and the migration of surface water in the active layer. The permafrost under the roads is therefore submitted to a warmer environment than in natural ground and his behavior reflects how the permafrost will act in the future with the global warming trend. The permafrost degradation dynamic under a road was studied at the Beaver Creek (Yukon) experimental site located on the Alaska Highway. Permafrost was characterized as near-zero Celcius and highly susceptible to differential thaw-settlement due to the ground ice spatial distribution. Ice-rich cryostructures typical of syngenetic permafrost (e.g. microlenticular) were abundant in the upper and lower cryostratigraphic units of fine-grained soils (Units 1, 2A, and 2C). The middle ice-poor silt layer (Unit 2B) characterized by porous cryostructure comprised the top of a buried ice-wedge network extending several meters in the underlying layers and susceptible to degradation by thermo-erosion. These particular features of the permafrost at the study site facilitated the formation of taliks (unfrozen zones) under the road which leaded to a greater water flow. We believe that water flow is promoting an acceleration of permafrost degradation by advective heat transfer. This process remains poorly studied and quantified in permafrost environment. Field data on topography, soil geotechnical properties, water table and preferential flow paths characterization, ground and water temperature and active layer and permafrost depth were collected to built seepage, heat transfer and coupled advecto-conductive models. Results indicated that advective heat transfer processes associated with groundwater flow can have a substantial impact on permafrost degradation. After one year, the active layer was 4 m deeper in the advecto-conductive heat transfer model than in the conductive heat transfer model and this was corroborated with measured field data. Groundwater flow processes should therefore be taken into account in permafrost evolution models and climate warming scenarios.
An evaluation of two types of nickel-titanium wires in terms of micromorphology and nickel ions' release following oral environment exposure.

PubMed

Ghazal, Abdul Razzak A; Hajeer, Mohammad Y; Al-Sabbagh, Rabab; Alghoraibi, Ibrahim; Aldiry, Ahmad

2015-01-01

This study aimed to compare superelastic and heat-activated nickel-titanium orthodontic wires' surface morphology and potential release of nickel ions following exposure to oral environment conditions. Twenty-four 20-mm-length distal cuts of superelastic (NiTi Force I®) and 24 20-mm-length distal cuts of heat-activated (Therma-Ti Lite®) nickel-titanium wires (American Orthodontics, Sheboygan, WI, USA) were divided into two equal groups: 12 wire segments left unused and 12 segments passively exposed to oral environment for 1 month. Scanning electron microscopy and atomic force microscopy were used to analyze surface morphology of the wires which were then immersed in artificial saliva for 1 month to determine potential nickel ions' release by means of atomic absorption spectrophotometer. Heat-activated nickel-titanium (NiTi) wires were rougher than superelastic wires, and both types of wires released almost the same amount of Ni ions. After clinical exposure, more surface roughness was recorded for superelastic NiTi wires and heat-activated NiTi wires. However, retrieved superelastic NiTi wires released less Ni ions in artificial saliva after clinical exposure, and the same result was recorded regarding heat-activated wires. Both types of NiTi wires were obviously affected by oral environment conditions; their surface roughness significantly increased while the amount of the released Ni ions significantly declined.
The evolution of the avian bill as a thermoregulatory organ.

PubMed

Tattersall, Glenn J; Arnaout, Bassel; Symonds, Matthew R E

2017-08-01

The avian bill is a textbook example of how evolution shapes morphology in response to changing environments. Bills of seed-specialist finches in particular have been the focus of intense study demonstrating how climatic fluctuations acting on food availability drive bill size and shape. The avian bill also plays an important but under-appreciated role in body temperature regulation, and therefore in energetics. Birds are endothermic and rely on numerous mechanisms for balancing internal heat production with biophysical constraints of the environment. The bill is highly vascularised and heat exchange with the environment can vary substantially, ranging from around 2% to as high as 400% of basal heat production in certain species. This heat exchange may impact how birds respond to heat stress, substitute for evaporative water loss at elevated temperatures or environments of altered water availability, or be an energetic liability at low environmental temperatures. As a result, in numerous taxa, there is evidence for a positive association between bill size and environmental temperatures, both within and among species. Therefore, bill size is both developmentally flexible and evolutionarily adaptive in response to temperature. Understanding the evolution of variation in bill size however, requires explanations of all potential mechanisms. The purpose of this review, therefore, is to promote a greater understanding of the role of temperature on shaping bill size over spatial gradients as well as developmental, seasonal, and evolutionary timescales. © 2016 Cambridge Philosophical Society.
The frequency response of a coupled ice sheet-ice shelf-ocean system to climate forcing variability

NASA Astrophysics Data System (ADS)

Goldberg, D.; Snow, K.; Jordan, J. R.; Holland, P.; Arthern, R. J.

2017-12-01

Changes at the West Antarctic ice-ocean boundary in recent decades has triggered significant increases in the regions contribution to global sea-level rise, coincident with large scale, and in some cases potentially unstable, grounding line retreat. Much of the induced change is thought to be driven by fluctuations in the oceanic heat available at the ice-ocean boundary, transported on-shelf via warm Circumpolar Deep Water (CDW). However, the processes in which ocean heat drives ice-sheet loss remains poorly understood, with observational studies routinely hindered by the extreme environment notorious to the Antarctic region. In this study we apply a novel synchronous coupled ice-ocean model, developed within the MITgcm, and are thus able to provide detailed insight into the impacts of short time scale (interannual to decadal) climate variability and feedbacks within the ice-ocean system. Feedbacks and response are assessed in an idealised ice-sheet/ocean-cavity configuration in which the far field ocean condition is adjusted to emulate periodic climate variability patterns. We reveal a non-linear response of the ice-sheet to periodic variations in thermocline depth. These non-linearities illustrate the heightened sensitivity of fast flowing ice-shelves to periodic perturbations in heat fluxes occurring at interannual and decadal time scales. The results thus highlight how small perturbations in variable climate forcing, like that of ENSO, may trigger large changes in ice-sheet response.
Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers

PubMed Central

Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

2016-01-01

Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers. PMID:27213422
Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers.

PubMed

Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

2016-05-20

Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers.
Numerical Simulations of the Boundary Layer Transition Flight Experiment

NASA Technical Reports Server (NTRS)

Tang, Chun Y.; Trumble, Kerry A.; Campbell, Charles H.; Lessard, Victor R.; Wood, William A.

2010-01-01

Computational Fluid Dynamics (CFD) simulations were used to study the possible effects that the Boundary Layer Transition (BLT) Flight Experiments may have on the heating environment of the Space Shuttle during its entry to Earth. To investigate this issue, hypersonic calculations using the Data-Parallel Line Relaxation (DPLR) and Langley Aerothermodynamic Upwind Relaxation (LAURA) CFD codes were computed for a 0.75 tall protuberance at flight conditions of Mach 15 and 18. These initial results showed high surface heating on the BLT trip and the areas surrounding the protuberance. Since the predicted peak heating rates would exceed the thermal limits of the materials selected to construct the BLT trip, many changes to the geometry were attempted in order to reduce the surface heat flux. The following paper describes the various geometry revisions and the resulting heating environments predicted by the CFD codes.

Principal sequence pattern analysis of episodes of excess mortality due to heat in the Barcelona metropolitan area.

PubMed

Peña, Juan Carlos; Aran, Montserrat; Raso, José Miguel; Pérez-Zanón, Nuria

2015-04-01

The aim of the study is to classify the synoptic sequences associated with excess mortality during the warm season in the Barcelona metropolitan area. To achieve this purpose, we undertook a principal sequence pattern analysis that incorporates different atmospheric levels, in an attempt at identifying the main features that account for dynamic and thermodynamic atmospheric processes. The sequence length was determined by the short-term displacement between temperature and mortality. To detect this lag, we applied the cross-correlation function to the residuals obtained from the modelling of the daily temperature and mortality series of summer. These residuals were estimated by means of an autoregressive integrated moving average (ARIMA) model. A 7-day sequence emerged as the basic temporal unit for evaluating the synoptic background that triggers the temperature related to excess mortality in the Barcelona metropolitan area. The principal sequence pattern analysis distinguished three main synoptic patterns: two dynamic configurations produced by southern fluxes related to an Atlantic low, which can be associated with heat waves recorded in southern Europe, and a third pattern identified by a stagnation situation associated with the persistence of a blocking anticyclone over Europe, related to heat waves recorded in northern and central western Europe.
Playing by the rules? Phenotypic adaptation to temperate environments in an American marsupial

PubMed Central

Harrigan, Ryan J.; Wayne, Robert K.

2018-01-01

Phenotypic variation along environmental gradients can provide evidence suggesting local adaptation has shaped observed morphological disparities. These differences, in traits such as body and extremity size, as well as skin and coat pigmentation, may affect the overall fitness of individuals in their environments. The Virginia opossum (Didelphis virginiana) is a marsupial that shows phenotypic variation across its range, one that has recently expanded into temperate environments. It is unknown, however, whether the variation observed in the species fits adaptive ecogeographic patterns, or if phenotypic change is associated with any environmental factors. Using phenotypic measurements of over 300 museum specimens of Virginia opossum, collected throughout its distribution range, we applied regression analysis to determine if phenotypes change along a latitudinal gradient. Then, using predictors from remote-sensing databases and a random forest algorithm, we tested environmental models to find the most important variables driving the phenotypic variation. We found that despite the recent expansion into temperate environments, the phenotypic variation in the Virginia opossum follows a latitudinal gradient fitting three adaptive ecogeographic patterns codified under Bergmann’s, Allen’s and Gloger’s rules. Temperature seasonality was an important predictor of body size variation, with larger opossums occurring at high latitudes with more seasonal environments. Annual mean temperature predicted important variation in extremity size, with smaller extremities found in northern populations. Finally, we found that precipitation and temperature seasonality as well as low temperatures were strong environmental predictors of skin and coat pigmentation variation; darker opossums are distributed at low latitudes in warmer environments with higher precipitation seasonality. These results indicate that the adaptive mechanisms underlying the variation in body size, extremity size and pigmentation are related to the resource seasonality, heat conservation, and pathogen-resistance hypotheses, respectively. Our findings suggest that marsupials may be highly susceptible to environmental changes, and in the case of the Virginia opossum, the drastic phenotypic evolution in northern populations may have arisen rapidly, facilitating the colonization of seasonal and colder habitats of temperate North America. PMID:29607255
Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

PubMed

Philp, Calvin P; Buchheit, Martin; Kitic, Cecilia M; Minson, Christopher T; Fell, James W

2017-07-01

To investigate whether a 5-d cycling training block in the heat (35°C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15°C) for improving intermittent-running performance in a cool environment (<18°C). Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 × 50-min sessions in total]) in a hot (HEAT, 35°C ± 1°C, 56% ± 9% RH) or cool environment (COOL, 15°C ± 3°C, 81% ± 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (V IFT ) was conducted in a cool environment (17°C ± 2°C, 58 ± 5% RH) before and twice after (1 and 3 d) the intervention. There was a likely small increase in V IFT in each group (HEAT, 0.5 ± 0.3 km/h, 1.5 ± 0.8 × smallest worthwhile change [SWC]; COOL, 0.4 ± 0.4 km/h, 1.6 ± 1.2 × SWC) 3 d postintervention, with no difference in change between the groups (0.5% ± 1.9%, 0.4 ± 1.4 × SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 ± 0.2 W/kg vs COOL 2.5 ± 0.3 W/kg, -21.7 ± 3.2 × SWC, 100/0/0). When cardiovascularexercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 × 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.
Heat pipes for use in a magnetic field

DOEpatents

Werner, R.W.; Hoffman, M.A.

1983-07-19

A heat pipe configuration for use in a magnetic field environment of a fusion reactor is disclosed. Heat pipes for operation in a magnetic field when liquid metal working fluids are used are optimized by flattening of the heat pipes having an unobstructed annulus which significantly reduces the adverse side region effect of the prior known cylindrically configured heat pipes. The flattened heat pipes operating in a magnetic field can remove 2--3 times the heat as a cylindrical heat pipe of the same cross sectional area. 4 figs.
Patterns of odour emission, thermogenesis and pollinator activity in cones of an African cycad: what mechanisms apply?

PubMed

Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

2013-09-01

Ontogenetic patterns of odour emissions and heating associated with plant reproductive structures may have profound effects on insect behaviour, and consequently on pollination. In some cycads, notably Macrozamia, temporal changes in emission of specific odour compounds and temperature have been interpreted as a 'push-pull' interaction in which pollinators are either attracted or repelled according to the concentration of the emitted volatiles. To establish which mechanisms occur in the large Encephalartos cycad clade, the temporal patterns of volatile emissions, heating and pollinator activity of cones of Encephalartos villosus in the Eastern Cape (EC) and KwaZulu Natal (KZN) of South Africa were investigated. Gas chromatography-mass spectrometry (GC-MS) analyses of Encephalartos villosus cone volatiles showed that emissions, dominated by eucalyptol and 2-isopropyl-3-methoxypyrazine in EC populations and (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene in the KZN populations, varied across developmental stages but did not vary significantly on a daily cycle. Heating in male cones was higher at dehiscence than during pre- and post-dehiscence, and reached a maximum at about 1830 h when temperatures were between 7·0 and 12·0 °C above ambient. Daily heating of female cones was less pronounced and reached a maximum at about 1345 h when it was on average between 0·9 and 3·0 °C above ambient. Insect abundance on male cones was higher at dehiscence than at the other stages and significantly higher in the afternoon than in the morning and evening. There are pronounced developmental changes in volatile emissions and heating in E. villosus cones, as well as strong daily changes in thermogenesis. Daily patterns of volatile emissions and pollinator abundance in E. villosus are different from those observed in some Macrozamia cycads and not consistent with the push-pull pattern as periods of peak odour emission do not coincide with mass exodus of insects from male cones.
Head-disk Interface Study for Heat Assisted Magnetic Recording (HAMR) and Plasmonic Nanolithography for Patterned Media

NASA Astrophysics Data System (ADS)

Xiong, Shaomin

The magnetic storage areal density keeps increasing every year, and magnetic recording-based hard disk drives provide a very cheap and effective solution to the ever increasing demand for data storage. Heat assisted magnetic recording (HAMR) and bit patterned media have been proposed to increase the magnetic storage density beyond 1 Tb/in2. In HAMR systems, high magnetic anisotropy materials are recommended to break the superparamagnetic limit for further scaling down the size of magnetic bits. However, the current magnetic transducers are not able to generate strong enough field to switch the magnetic orientations of the high magnetic anisotropy material so the data writing is not able to be achieved. So thermal heating has to be applied to reduce the coercivity for the magnetic writing. To provide the heating, a laser is focused using a near field transducer (NFT) to locally heat a ~(25 nm)2 spot on the magnetic disk to the Curie temperature, which is ~ 400 C-600°C, to assist in the data writing process. But this high temperature working condition is a great challenge for the traditional head-disk interface (HDI). The disk lubricant can be depleted by evaporation or decomposition. The protective carbon overcoat can be graphitized or oxidized. The surface quality, such as its roughness, can be changed as well. The NFT structure is also vulnerable to degradation under the large number of thermal load cycles. The changes of the HDI under the thermal conditions could significantly reduce the robustness and reliability of the HAMR products. In bit patterned media systems, instead of using the continuous magnetic granular material, physically isolated magnetic islands are used to store data. The size of the magnetic islands should be about or less than 25 nm in order to achieve the storage areal density beyond 1 Tb/in2. However, the manufacture of the patterned media disks is a great challenge for the current optical lithography technology. Alternative lithography solutions, such as nanoimprint, plasmonic nanolithography, could be potential candidates for the fabrication of patterned disks. This dissertation focuses mainly on: (1) an experimental study of the HDI under HAMR conditions (2) exploration of a plasmonic nanolithography technology. In this work, an experimental HAMR testbed (named "Cal stage") is developed to study different aspects of HAMR systems, including the tribological head-disk interface and heat transfer in the head-disk gap. A temperature calibration method based on magnetization decay is proposed to obtain the relationship between the laser power input and temperature increase on the disk. Furthermore, lubricant depletion tests under various laser heating conditions are performed. The effects of laser heating repetitions, laser power and disk speeds on lubricant depletion are discussed. Lubricant depletion under the optical focused laser beam heating and the NFT heating are compared, revealing that thermal gradient plays an important role for lubricant depletion. Lubricant reflow behavior under various conditions is also studied, and a power law dependency of lubricant depletion on laser heating repetitions is obtained from the experimental results. A conductive-AFM system is developed to measure the electrical properties of thin carbon films. The conductivity or resistivity is a good parameter for characterizing the sp2/sp3 components of the carbon films. Different heating modes are applied to study the degradation of the carbon films, including temperature-controlled electric heater heating, focused laser beam heating and NFT heating. It is revealed that the temperature and heating duration significantly affect the degradation of the carbon films. Surface reflectivity and roughness are changed under certain heating conditions. The failure of the NFT structure during slider flying is investigated using our in-house fabricated sliders. In order to extend the lifetime of the NFT, a two-stage heating scheme is proposed and a numerical simulation has verified the feasibility of this new scheme. The heat dissipated around the NFT structure causes a thermal protrusion. There is a chance for contact to occur between the protrusion and disk which can result in a failure of the NFT. A design method to combine both TFC protrusion and laser induced NFT protrusion is proposed to reduce the fly-height modulation and chance of head-disk contact. Finally, an integrated plasmonic nanolithography machine is introduced to fabricate the master template for patterned disks. The plasmonic nanolithography machine uses a flying slider with a plasmonic lens to expose the thermal resist on a spinning wafer. The system design, optimization and integration have been performed over the past few years. Several sub-systems of the plasmonic nanolithography machine, such as the radial and circumferential direction position control, high speed pattern generation, are presented in this work. The lithography results are shown as well.
An Internal Thermal Environment Model of an Aluminized Solid Rocket Motor with Experimental Validation

NASA Technical Reports Server (NTRS)

Martin, Heath T.

2015-01-01

Due to the severity of the internal solid rocket motor (SRM) environment, very few direct measurements of that environment exist; therefore, the appearance of such data provides a unique opportunity to assess current thermal/fluid modeling capabilities. As part of a previous study of SRM internal insulation performance, the internal thermal environment of a laboratory-scale SRM featuring aluminized propellant was characterized with two types of custom heat-flux calorimeters: one that measured the total heat flux to a graphite slab within the SRM chamber and another that measured the thermal radiation flux. Therefore, in the current study, a thermal/fluid model of this lab-scale SRM was constructed using ANSYS Fluent to predict not only the flow field structure within the SRM and the convective heat transfer to the interior walls, but also the resulting dispersion of alumina droplets and the radiative heat transfer to the interior walls. The dispersion of alumina droplets within the SRM chamber was determined by employing the Lagrangian discrete phase model that was fully coupled to the Eulerian gas-phase flow. The P1-approximation was engaged to model the radiative heat transfer through the SRM chamber where the radiative contributions of the gas phase were ignored and the aggregate radiative properties of the alumina dispersion were computed from the radiative properties of its individual constituent droplets, which were sourced from literature. The convective and radiative heat fluxes computed from the thermal/fluid model were then compared with those measured in the lab-scale SRM test firings and the modeling approach evaluated.
The Thermal Regime Around Buried Submarine High-Voltage Cables

NASA Astrophysics Data System (ADS)

Emeana, C. J.; Dix, J.; Henstock, T.; Gernon, T.; Thompson, C.; Pilgrim, J.

2015-12-01

The expansion of offshore renewable energy infrastructure and the desire for "trans-continental shelf" power transmission, all require the use of submarine High Voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70oC and are typically buried at depths of 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the thermal properties of near surface shelf sediments are poorly understood and this increases the uncertainty in determining the required cable current ratings, cable reliability and the potential effects on the sedimentary environments. We present temperature measurements from a 2D laboratory experiment, designed to represent a buried, submarine HV cable. We used a large (2.5 m-high) tank, filled with water-saturated ballotini and instrumented with 120 thermocouples, which measured the time-dependent 2D temperature distributions around the heat source. The experiments use a buried heat source to represent a series of realistic cable surface temperatures with the aim for identifying the thermal regimes generated within typical non-cohesive shelf sediments: coarse silt, fine sand and very coarse sand. The steady state heat flow regimes, and normalised and radial temperature distributions were assessed. Our results show that at temperatures up to 60°C above ambient, the thermal regimes are conductive for the coarse silt sediments and convective for the very coarse sand sediments even at 7°C above ambient. However, the heat flow pattern through the fine sand sediment shows a transition from conductive to convective heat flow at a temperature of approximately 20°C above ambient. These findings offer an important new understanding of the thermal regimes associated with submarine HV cables buried in different substrates and has huge impacts on cable ratings as the IEC 60287 standard only considers conductive heat flow as well as other potential near surface impacts.
Diurnal Variations in Global Joule Heating Morphology and Magnitude Due To Neutral Winds

NASA Astrophysics Data System (ADS)

Billett, D. D.; Grocott, A.; Wild, J. A.; Walach, M.-T.; Kosch, M. J.

2018-03-01

In the polar ionosphere, variations in Joule heating are significantly controlled by changes in plasma convection, such as that brought about by changes in the interplanetary magnetic field. However, another important consideration when calculating Joule heating is the velocity difference between this plasma and the neutral thermosphere colocated with the ionosphere. Neutral wind data are often difficult to obtain on a global scale; thus, Joule heating has often previously been calculated assuming that neutral velocities are small and can therefore be neglected. Previous work has shown the effect of neutral winds on Joule heating estimations to be more significant than originally thought; however, the diurnal variations of the neutrals due to changes in solar pressure gradients and Coriolis forces have yet to have their impact on Joule heating assessed. We show this universal time effect to be significant in calculating Joule heating and thus can differ significantly from that calculated by neglecting the neutrals. In this study, we use empirical models for the neutral wind, conductivities, and magnetic field to create Northern Hemispheric patterns of Joule heating for approximately 800,000 individual plasma convection patterns generated using data from the Super Dual Auroral Radar Network. From this, a statistical analysis of how Joule heating varies in morphology and magnitude with universal time is shown for differing seasons and levels of geomagnetic activity. We find that neutral winds do play a significant role in the morphology and total energy output of Joule heating.
Heat-flow measurements at shot points along the 1978 Saudi Arabia seismic deep-refraction line; Part I, Results of the measurements

USGS Publications Warehouse

Gettings, M.E.; Showail, Abdullah

1982-01-01

Heat-flow measurements were made at five onland shot points of the 1978 Saudi Arabian seismic deep-refraction line, which sample major tectonic elements of the Arabian Shield along a profile from Ar Riyad to the Farasan Islands. Because of the pattern drilling at each shot point, several holes (60 m deep) could be logged for temperature at each site and thus allow a better estimate of the geothermal gradient. Each site was mapped and sampled in detail, and modal and. chemical analyses of representative specimens were made in the laboratory. Thermal conductivities were computed from the modal analyses and single-mineral conductivity data. The resulting heat-flow values, combined with published values for the Red Sea and coastal plain, indicate a three-level pattern, with a heat flow of about 4.5 heat-flow unit (HFU) over the Red Sea axial trough, about 3.0 HFU over the shelf and coastal plain, and an essentially constant 1.0 HFU over the Arabian Shield at points well away from the suture zone with the oceanic crust. At three sites where the rocks are granitic, gamma-ray spectrometry techniques were employed to estimate thorium, potassium, and uranium concentrations. The resulting plot of heat generation versus heat flow suggests that in the Arabian Shield the relationship between heat flow and heat production is not linear. More heat-flow data are essential to establish or reject this conclusion.
Radiation detector system having heat pipe based cooling

DOEpatents

Iwanczyk, Jan S.; Saveliev, Valeri D.; Barkan, Shaul

2006-10-31

A radiation detector system having a heat pipe based cooling. The radiation detector system includes a radiation detector thermally coupled to a thermo electric cooler (TEC). The TEC cools down the radiation detector, whereby heat is generated by the TEC. A heat removal device dissipates the heat generated by the TEC to surrounding environment. A heat pipe has a first end thermally coupled to the TEC to receive the heat generated by the TEC, and a second end thermally coupled to the heat removal device. The heat pipe transfers the heat generated by the TEC from the first end to the second end to be removed by the heat removal device.
Oxidation effects on the mechanical properties of SiC fiber-reinforced reaction-bonded silicon nitride matrix composites

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.

1989-01-01

The room temperature mechanical properties of SiC fiber reinforced reaction bonded silicon nitride composites were measured after 100 hrs exposure at temperatures to 1400 C in nitrogen and oxygen environments. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers in a reaction bonded Si3N4 matrix. The results indicate that composites heat treated in a nitrogen environment at temperatures to 1400 C showed deformation and fracture behavior equivalent to that of the as-fabricated composites. Also, the composites heat treated in an oxidizing environment beyond 400 C yielded significantly lower tensile strength values. Specifically in the temperature range from 600 to 1000 C, composites retained approx. 40 percent of their as-fabricated strength, and those heat treated in the temperatures from 1200 to 1400 C retained 70 percent. Nonetheless, for all oxygen heat treatment conditions, composite specimens displayed strain capability beyond the matrix fracture stress; a typical behavior of a tough composite.
Material processing of convection-driven flow field and temperature distribution under oblique gravity

NASA Technical Reports Server (NTRS)

Hung, R. J.

1995-01-01

A set of mathematical formulation is adopted to study vapor deposition from source materials driven by heat transfer process under normal and oblique directions of gravitational acceleration with extremely low pressure environment of 10(exp -2) mm Hg. A series of time animation of the initiation and development of flow and temperature profiles during the course of vapor deposition has been obtained through the numerical computation. Computations show that the process of vapor deposition has been accomplished by the transfer of vapor through a fairly complicated flow pattern of recirculation under normal direction gravitational acceleration. It is obvious that there is no way to produce a homogeneous thin crystalline films with fine grains under such a complicated flow pattern of recirculation with a non-uniform temperature distribution under normal direction gravitational acceleration. There is no vapor deposition due to a stably stratified medium without convection for reverse normal direction gravitational acceleration. Vapor deposition under oblique direction gravitational acceleration introduces a reduced gravitational acceleration in vertical direction which is favorable to produce a homogeneous thin crystalline films. However, oblique direction gravitational acceleration also induces an unfavorable gravitational acceleration along horizontal direction which is responsible to initiate a complicated flow pattern of recirculation. In other words, it is necessary to carry out vapor deposition under a reduced gravity in the future space shuttle experiments with extremely low pressure environment to process vapor deposition with a homogeneous crystalline films with fine grains. Fluid mechanics simulation can be used as a tool to suggest most optimistic way of experiment with best setup to achieve the goal of processing best nonlinear optical materials.
Tank Pressure Control Experiment: Thermal Phenomena in Microgravity

NASA Technical Reports Server (NTRS)

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

1996-01-01

The report presents the results of the flight experiment Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP) performed in the microgravity environment of the space shuttle. TPCE/TP, flown on the Space Transportation System STS-52, was a second flight of the Tank Pressure Control Experiment (TPCE). The experiment used Freon 113 at near saturation conditions. The test tank was filled with liquid to about 83% by volume. The experiment consisted of 21 tests. Each test generally started with a heating phase to increase the tank pressure and to develop temperature stratification in the fluid, followed by a fluid mixing phase for the tank pressure reduction and fluid temperature equilibration. The heating phase provided pool boiling data from large (relative to bubble sizes) heating surfaces (0.1046 m by 0.0742 m) at low heat fluxes (0.23 to 1.16 kW/sq m). The system pressure and the bulk liquid subcooling varied from 39 to 78 kPa and 1 to 3 C, respectively. The boiling process during the entire heating period, as well as the jet-induced mixing process for the first 2 min of the mixing period, was also recorded on video. The unique features of the experimental results are the sustainability of high liquid superheats for long periods and the occurrence of explosive boiling at low heat fluxes (0.86 to 1.1 kW/sq m). For a heat flux of 0.97 kW/sq m, a wall superheat of 17.9 C was attained in 10 min of heating. This superheat was followed by an explosive boiling accompanied by a pressure spike of about 38% of the tank pressure at the inception of boiling. However, at this heat flux the vapor blanketing the heating surface could not be sustained. Steady nucleate boiling continued after the explosive boiling. The jet-induced fluid mixing results were obtained for jet Reynolds numbers of 1900 to 8000 and Weber numbers of 0.2 to 6.5. Analyses of data from the two flight experiments (TPCE and TPCE/TP) and their comparison with the results obtained in drop tower experiments suggest that as Bond number approaches zero the flow pattern produced by an axial jet and the mixing time can be predicted by the Weber number.
40 CFR 96.76 - Additional requirements to provide heat input data for allocations purposes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... heat input data for allocations purposes. 96.76 Section 96.76 Protection of Environment ENVIRONMENTAL... to provide heat input data for allocations purposes. (a) The owner or operator of a unit that elects... also monitor and report heat input at the unit level using the procedures set forth in part 75 of this...
40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.

Code of Federal Regulations, 2010 CFR

2010-07-01

... heat input rate. 75.83 Section 75.83 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass emissions and heat input rate in accordance with the procedures in sections 9.1 through 9.3 of appendix F to...
Heat Pipes Reduce Engine-Exhaust Emissions

NASA Technical Reports Server (NTRS)

Schultz, D. F.

1986-01-01

Increased fuel vaporization raises engine efficiency. Heat-pipe technology increased efficiency of heat transfer beyond that obtained by metallic conduction. Resulted in both improved engine operation and reduction in fuel consumption. Raw material conservation through reduced dependence on strategic materials also benefit from this type of heat-pipe technology. Applications result in improved engine performance and cleaner environment.
40 CFR 63.6092 - Are duct burners and waste heat recovery units covered by subpart YYYY?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Are duct burners and waste heat... Stationary Combustion Turbines What This Subpart Covers § 63.6092 Are duct burners and waste heat recovery units covered by subpart YYYY? No, duct burners and waste heat recovery units are considered steam...
40 CFR 96.76 - Additional requirements to provide heat input data for allocations purposes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... heat input data for allocations purposes. 96.76 Section 96.76 Protection of Environment ENVIRONMENTAL... to provide heat input data for allocations purposes. (a) The owner or operator of a unit that elects... also monitor and report heat input at the unit level using the procedures set forth in part 75 of this...
40 CFR 63.6092 - Are duct burners and waste heat recovery units covered by subpart YYYY?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Are duct burners and waste heat... Stationary Combustion Turbines What This Subpart Covers § 63.6092 Are duct burners and waste heat recovery units covered by subpart YYYY? No, duct burners and waste heat recovery units are considered steam...

40 CFR 63.6092 - Are duct burners and waste heat recovery units covered by subpart YYYY?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Are duct burners and waste heat... Stationary Combustion Turbines What This Subpart Covers § 63.6092 Are duct burners and waste heat recovery units covered by subpart YYYY? No, duct burners and waste heat recovery units are considered steam...
40 CFR 96.76 - Additional requirements to provide heat input data for allocations purposes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... heat input data for allocations purposes. 96.76 Section 96.76 Protection of Environment ENVIRONMENTAL... to provide heat input data for allocations purposes. (a) The owner or operator of a unit that elects... also monitor and report heat input at the unit level using the procedures set forth in part 75 of this...
40 CFR 96.76 - Additional requirements to provide heat input data for allocations purposes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... heat input data for allocations purposes. 96.76 Section 96.76 Protection of Environment ENVIRONMENTAL... to provide heat input data for allocations purposes. (a) The owner or operator of a unit that elects... also monitor and report heat input at the unit level using the procedures set forth in part 75 of this...
Impact of pavements on the urban heat island : final project report.

DOT National Transportation Integrated Search

2016-10-01

Increasing urbanization has led to the development of Urban Heat Islands (UHIs), with serious implications for the environment. Pavements play a role in this by absorbing and storing more heat than the natural surfaces that they replace. To quantify ...
Vapor-Generator Wand Helps To Reveal Airflow Patterns

NASA Technical Reports Server (NTRS)

Robelen, David B.

1993-01-01

In vapor-generator wand, liquid propylene glycol flows into electrically heated stainless-steel tube. Liquid boils in heated tube, and emerging vapor forms dense, smoke-like fog used to make airflow patterns visible. Built in variety of sizes, suitable for uses ranging from tabletop demonstrations to research in wind tunnels. For best viewing, plume illuminated by bright, focused incandescent spotlight at right angle to viewing direction. Viewing further enhanced by coating walls of test chamber with flat, dark color to minimize reflections and increase contrast.
Development of a Pattern Recognition Methodology for Determining Operationally Optimal Heat Balance Instrumentation Calibration Schedules

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

Kurt Beran; John Christenson; Dragos Nica

2002-12-15

The goal of the project is to enable plant operators to detect with high sensitivity and reliability the onset of decalibration drifts in all of the instrumentation used as input to the reactor heat balance calculations. To achieve this objective, the collaborators developed and implemented at DBNPS an extension of the Multivariate State Estimation Technique (MSET) pattern recognition methodology pioneered by ANAL. The extension was implemented during the second phase of the project and fully achieved the project goal.
Risk from drought and extreme heat in Russian wheat production and its relation to atmospheric blocking and teleconnection patterns

NASA Astrophysics Data System (ADS)

Giannakaki, Paraskevi; Calanca, Pierluigi

2017-04-01

Russia has become one of the leading wheat exporters worldwide. Major breakdowns in Russian wheat production induced by extreme weather events are therefore of high significance not only for the domestic but also for the global market. Wheat production in south-western Russia, the main growing area, suffers in particular from the adverse effects of drought and heat waves. For this reason knowledge of the occurrence of this type of extreme events and of the processes that lead to adverse conditions is of paramount importance for risk management. The negative impacts of heat waves and drought are particularly severe when anomalous conditions persist in time. As an example, a blocking event in summer 2010 resulted in one of the warmest and worst drought conditions in Russia's recent history. The latter caused a decline in Russian wheat production by more than 30%, which in turn prompted the Russian government to issue an export ban that lasted until summer 2011. In view of this, the question of course arises of how much of the negative variations in Russian wheat production levels can be explained by blocking events and other features of the large-scale atmospheric circulation. Specific questions are: how often are blocking events over Russia associated with extreme high temperatures and dry conditions? Which of the teleconnection patterns are correlated with drought and heat stress conditions in the area? Answering these questions can contribute to a develop strategies for agricultural risk management. In this contribution we present results of a study that aims at characterizing the occurrence of adverse weather conditions in south-western Russia in relation to atmospheric blocking and teleconnection patterns such as East Atlantic/Western Russia pattern, the Polar/Eurasia pattern, the North Atlantic Oscillation and the Scandinavia pattern. The analysis relies on weather data for 1980-2014 from 130 stations distributed across the wheat production area. The account for similarities in the occurrence of extreme heat, stations are clustered according to 90th percentile of daily maximum temperature. The results indicate that adverse conditions in the area are significantly correlated with the occurrence of blocking events and with the phase of some teleconnection patterns.
Biophysical aspects of human thermoregulation during heat stress.

PubMed

Cramer, Matthew N; Jay, Ollie

2016-04-01

Humans maintain a relatively constant core temperature through the dynamic balance between endogenous heat production and heat dissipation to the surrounding environment. In response to metabolic or environmental disturbances to heat balance, the autonomic nervous system initiates cutaneous vasodilation and eccrine sweating to facilitate higher rates of dry (primarily convection and radiation) and evaporative transfer from the body surface; however, absolute heat losses are ultimately governed by the properties of the skin and the environment. Over the duration of a heat exposure, the cumulative imbalance between heat production and heat dissipation leads to body heat storage, but the consequent change in core temperature, which has implications for health and safety in occupational and athletic settings particularly among certain clinical populations, involves a complex interaction between changes in body heat content and the body's morphological characteristics (mass, surface area, and tissue composition) that collectively determine the body's thermal inertia. The aim of this review is to highlight the biophysical aspects of human core temperature regulation by outlining the principles of human energy exchange and examining the influence of body morphology during exercise and environmental heat stress. An understanding of the biophysical factors influencing core temperature will enable researchers and practitioners to better identify and treat individuals/populations most vulnerable to heat illness and injury during exercise and extreme heat events. Further, appropriate guidelines may be developed to optimize health, safety, and work performance during heat stress. Copyright © 2016 Elsevier B.V. All rights reserved.
A Global Assessment of Oceanic Heat Loss: Conductive Cooling and Hydrothermal Redistribution of Heat

NASA Astrophysics Data System (ADS)

Hasterok, D. P.; Chapman, D. S.; Davis, E. E.

2011-12-01

A new dataset of ~15000 oceanic heat flow measurements is analyzed to determine the conductive heat loss through the seafloor. Many heat flow values in seafloor younger than 60 Ma are lower than predicted by models of conductively cooled lithosphere. This heat flow deficit is caused by ventilated hydrothermal circulation discharging at crustal outcrops or through thin sedimentary cover. Globally filtering of heat flow data to retain sites with sediment cover >400 m thick and located >60 km from the nearest seamount minimizes the effect of hydrothermal ventilation. Filtered heat flow exhibit a much higher correlation coefficient with seafloor age (up to 0.95 for filtered data in contrast to 0.5 for unfiltered data) and lower variability (reduction by 30%) within an age bin. A small heat flow deficit still persists at ages <25 Ma, possibly as a result of global filtering limitations and incomplete thermal rebound following sediment burial. Detailed heat flow surveys co-located with seismic data can identify environments favoring conductive heat flow; heat flow collected in these environments is higher than that determined by the global dataset, and is more consistent with conductive cooling of the lithosphere. The new filtered data analysis and a growing number of site specific surveys both support estimates of global heat loss in the range 40-47 TW. The estimated hydrothermal deficit is consistent with estimates from geochemical studies ~7 TW, but is a few TW lower than previous estimates derived from heat flow determinations.
Acclimatization to extreme heat

NASA Astrophysics Data System (ADS)

Warner, M. E.; Ganguly, A. R.; Bhatia, U.

2017-12-01

Heat extremes throughout the globe, as well as in the United States, are expected to increase. These heat extremes have been shown to impact human health, resulting in some of the highest levels of lives lost as compared with similar natural disasters. But in order to inform decision makers and best understand future mortality and morbidity, adaptation and mitigation must be considered. Defined as the ability for individuals or society to change behavior and/or adapt physiologically, acclimatization encompasses the gradual adaptation that occurs over time. Therefore, this research aims to account for acclimatization to extreme heat by using a hybrid methodology that incorporates future air conditioning use and installation patterns with future temperature-related time series data. While previous studies have not accounted for energy usage patterns and market saturation scenarios, we integrate such factors to compare the impact of air conditioning as a tool for acclimatization, with a particular emphasis on mortality within vulnerable communities.
Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

NASA Technical Reports Server (NTRS)

Glass, Christopher E.

1990-01-01

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.
Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

NASA Astrophysics Data System (ADS)

Glass, Christopher E.

1990-08-01

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.
Heat transfer and hydrodynamic analysis in an industrial circulating fluidized bed boiler

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

Di Maggio, T.; Piedfer, O.; Jestin, L.

In order to scale-up Circulating Fluidized Bed boilers (up to 600 MWe), Electricite de France has initiated a Research and Development program including: laboratory work on mock-up, numerical modeling and on-site tests in the 125 MWe CFB Emile Huchet plant. This paper is devoted to on-site measurements analysis in two main components of this industrial unit: the external fluidized bed heat exchangers and the backpass. This study particularly concerns hydrodynamics and heat transfer with the final target of developing a physical model of a CFB unit. The first part of this paper describes the specific instrumentation set up on externalmore » fluidized bed heat exchangers. The comparison between experimental data collected on these heat exchangers and the theoretical heat transfer models mainly used, shows a great difference about the value of the overall heat transfer coefficient. To explain this discrepancy, the particle flow pattern initially used in the thermal balance calculation is modified and a solid bypass is introduced. The analysis of the by-pass behavior, connected to the geometrical and operating parameters of each exchanger, confirms the particle flow pattern suggested. The second part of this paper shows an analysis of the specific measurements set up on the backpass to study heat transfer. The physical model of heat transfer used to assess the importance of each convection, radiation and conduction components is presented. This model allows one to assess the influence of heat exchangers design on heat transfer. Moreover, the analysis of heat transfer variations during sweeping cycles gives the amount of dust that is removed from the heat exchanger tubes. These results are used to evaluate the amount of power that can be recovered by optimizing both design and sweeping of the backpass.« less
R and D plans for Broad Area Energy Utilization Network System

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

Takemura, Yozo; Ishida, Hiromi; Yanagishita, Hiroshi

1995-12-31

In Japan, approximately 60 percent of the primary energy supply is lost as waste heat due to low thermal energy conversion efficiency. A lot of effort has been made towards energy conservation in industry since 1973 when the oil crisis happened. However, waste heat is not recovered sufficiently at low temperature. Since most of energy in residential and commercial areas is used for air-conditioning and hot water, the temperature of heat for residential and commercial use is almost equal to that of waste heat discharged from industrial sources. Therefore, the Broad Area Energy Utilization Network System (Eco-Energy City) project, whichmore » started in 1993 and will continue over a period of 8 years, is a large-scale national energy conservation project of the Agency of Industrial Science and technology (AIST) of the Ministry of International Trade and Industry (MITI). The aim of this project is to accelerate the full scale utilization of industrial waste heat for residential and commercial use by technological breakthroughs. The concept of the project is as follows: (1) Waste and unutilized heat discharged from industrial sources at relatively high temperature is recovered very efficiently, in multiple stages and in various ways. (2) Recovered heat is transported with a small heat loss over a long distance to residential and commercial areas that have various patterns of consuming relatively low-temperature heat. (3) Transported heat is supplied at consumer sites in different ways depending on the individual consumption pattern. (4) Thermal energy is utilized in the following forms: Cascaded use, combined use and recycling. The key to success is to develop innovative technologies of heat recovery, heat transport, heat supply and systematization of energy supply and demand.« less
Heat Illness: A Handbook for Medical Officers

DTIC Science & Technology

1991-06-03

Recommendations to planning staffs should eii~piliasve theC irportwnce of adequate sleep and food to reduce the likelihood of heat casuaRtift-ýs...experience much greater heat strain in uniforms, such as the BDO, that restrict heat exchange with the environment. Will the recruits have the...the sklf.- to thermoregulate and increase the risk of heat Illness. Lack of sleep and food will reduce thermoregiilatomy capacity. Medical Plannin-a
Warming up human body by nanoporous metallized polyethylene textile.

PubMed

Cai, Lili; Song, Alex Y; Wu, Peilin; Hsu, Po-Chun; Peng, Yucan; Chen, Jun; Liu, Chong; Catrysse, Peter B; Liu, Yayuan; Yang, Ankun; Zhou, Chenxing; Zhou, Chenyu; Fan, Shanhui; Cui, Yi

2017-09-19

Space heating accounts for the largest energy end-use of buildings that imposes significant burden on the society. The energy wasted for heating the empty space of the entire building can be saved by passively heating the immediate environment around the human body. Here, we demonstrate a nanophotonic structure textile with tailored infrared (IR) property for passive personal heating using nanoporous metallized polyethylene. By constructing an IR-reflective layer on an IR-transparent layer with embedded nanopores, the nanoporous metallized polyethylene textile achieves a minimal IR emissivity (10.1%) on the outer surface that effectively suppresses heat radiation loss without sacrificing wearing comfort. This enables 7.1 °C decrease of the set-point compared to normal textile, greatly outperforming other radiative heating textiles by more than 3 °C. This large set-point expansion can save more than 35% of building heating energy in a cost-effective way, and ultimately contribute to the relief of global energy and climate issues.Energy wasted for heating the empty space of the entire building can be saved by passively heating the immediate environment around the human body. Here, the authors show a nanophotonic structure textile with tailored infrared property for passive personal heating using nanoporous metallized polyethylene.
Energy budgets and a climate space diagram for the turtle, Chrysemys scripta

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

Foley, R. E.

1976-01-01

Heat energy budgets were computed and a steady state climate space was generated for a 1000 g red-eared turtle (Chrysemys scripta). Evaporative water loss (EWL) was measured from C. scripta at three wind speeds (10-400 cm sec/sup -1/) and at four air temperatures (5 to 35/sup 0/C) in a wind tunnel. EWL increased as air temperature and wind speed increased. Smaller turtles dehydrated at a faster rate than large turtles. Heat transfer by convection was measured from aluminum castings of C. scripta at three temperature differences between casting and air (..delta..T 15/sup 0/, 10/sup 0/ and 5/sup 0/C) for threemore » windspeeds (10 to 400 cm sec/sup -1/). Convective heat transfer coefficients increased as wind speed and ..delta..T increased. Wind speed has a large effect on the shape of the climate space. At high wind speeds, heat loss by evaporation and convection are greatly increased. In still air (10 cm sec/sup -1/), a turtle cannot remain exposed to full sunlight when air temperatures exceed 19/sup 0/C. When wind speed increases to 400 cm sec/sup -1/, the turtle can bask for long periods of time at temperatures as high as 32/sup 0/C. Basking patterns of C. scripta probably shift from a unimodal pattern in the spring to a bimodal pattern in summer and return to a unimodal pattern in fall. Terrestrial activity may be extensive in the spring and fall but is limited during the hot summer months to periods of rainfall. Nesting activities cannot occur around solar noon because increased metabolic heat loading and high solar radiation intensity could cause death.« less
Do diurnal patterns of branch carbon uptake and transpiration recover after heat waves? Results from a Mediterranean-type ecosystem experiencing seasonal and exceptional drought

NASA Astrophysics Data System (ADS)

Pivovaroff, A. L.; Pesqueira, A.; Sun, W.; Seibt, U.

2016-12-01

Mediterranean-type ecosystems are biodiversity hotspots, but increasing temperature and changes in precipitation will have significant impacts on vegetation, as evidenced by the current die-back of many woody species in southern California, USA, due to exceptional drought conditions. We installed flow-through chambers on four native woody plant species at Stunt Ranch, a University of California Natural Reserve System site, in order to continuously monitor fluxes of carbon and water at the branch-scale from the growing season through the annual seasonal drought period. Study species included Heteromeles arbutifolia, Malosma laurina, Salvia leucophylla, and Quercus agrifolia. Here we present the results of diurnal flux patterns before, during, and after two extreme heat waves events, when daily maximum temperatures doubled. Under typical summer conditions, which include hot, sunny days, study species exhibited two peaks in carbon assimilation during a diurnal cycle: a peak in the morning and a smaller, secondary peak in the afternoon, separated by a midday depression. During heat wave events, which generally lasted 3 days, species exhibited a small morning peak and no afternoon peak at all. All study species returned to their pre-heat wave diurnal flux patterns, which included the second afternoon peak, when weather conditions returned to normal. Since soil moisture was not affected by the short-term heat wave events, we conclude that the pronounced changes in diurnal patterns, including disappearance of the secondary afternoon peak, are the result of stomatal regulation in response to atmospheric water demand rather than root responses to soil moisture deficits. Our results demonstrate that carbon uptake of native species may be impacted under ongoing climate change when increased temperatures and drought conditions may be sustained.
Occupational heat stress assessment and protective strategies in the context of climate change

NASA Astrophysics Data System (ADS)

Gao, Chuansi; Kuklane, Kalev; Östergren, Per-Olof; Kjellstrom, Tord

2018-03-01

Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.
Occupational heat stress assessment and protective strategies in the context of climate change.

PubMed

Gao, Chuansi; Kuklane, Kalev; Östergren, Per-Olof; Kjellstrom, Tord

2018-03-01

Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.

Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

NASA Technical Reports Server (NTRS)

Golliher, Eric L.; Yao, S. C.

2015-01-01

Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.
Evaluating Heat Pipe Performance in 1/6 g Acceleration: Problems and Prospects

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; McCollum, Timothy A.; Gibson, Marc A.; Sanzi, James L.; Sechkar, Edward A.

2011-01-01

Heat pipes composed of titanium and water are being considered for use in the heat rejection system of a fission power system option for lunar exploration. Placed vertically on the lunar surface, the heat pipes would operate as thermosyphons in the 1/6 g environment. The design of thermosyphons for such an application is determined, in part, by the flooding limit. Flooding is composed of two components, the thickness of the fluid film on the walls of the thermosyphon and the interaction of the fluid flow with the concurrent vapor counter flow. Both the fluid thickness contribution and interfacial shear contribution are inversely proportional to gravity. Hence, evaluating the performance of a thermosyphon in a 1 g environment on Earth may inadvertently lead to overestimating the performance of the same thermosyphon as experienced in the 1/6 g environment on the moon. Several concepts of varying complexity have been proposed for evaluating thermosyphon performance in reduced gravity, ranging from tilting the thermosyphons on Earth based on a cosine function, to flying heat pipes on a low-g aircraft. This paper summarizes the problems and prospects for evaluating thermosyphon performance in 1/6 g.
Active and passive heat stress similarly compromise tolerance to a simulated hemorrhagic challenge.

PubMed

Pearson, J; Lucas, R A I; Schlader, Z J; Zhao, J; Gagnon, D; Crandall, C G

2014-10-01

Passive heat stress increases core and skin temperatures and reduces tolerance to simulated hemorrhage (lower body negative pressure; LBNP). We tested whether exercise-induced heat stress reduces LBNP tolerance to a greater extent relative to passive heat stress, when skin and core temperatures are similar. Eight participants (6 males, 32 ± 7 yr, 176 ± 8 cm, 77.0 ± 9.8 kg) underwent LBNP to presyncope on three separate and randomized occasions: 1) passive heat stress, 2) exercise in a hot environment (40°C) where skin temperature was moderate (36°C, active 36), and 3) exercise in a hot environment (40°C) where skin temperature was matched relative to that achieved during passive heat stress (∼38°C, active 38). LBNP tolerance was quantified using the cumulative stress index (CSI). Before LBNP, increases in core temperature from baseline were not different between trials (1.18 ± 0.20°C; P > 0.05). Also before LBNP, mean skin temperature was similar between passive heat stress (38.2 ± 0.5°C) and active 38 (38.2 ± 0.8°C; P = 0.90) trials, whereas it was reduced in the active 36 trial (36.6 ± 0.5°C; P ≤ 0.05 compared with passive heat stress and active 38). LBNP tolerance was not different between passive heat stress and active 38 trials (383 ± 223 and 322 ± 178 CSI, respectively; P = 0.12), but both were similarly reduced relative to active 36 (516 ± 147 CSI, both P ≤ 0.05). LBNP tolerance is not different between heat stresses induced either passively or by exercise in a hot environment when skin temperatures are similarly elevated. However, LBNP tolerance is influenced by the magnitude of the elevation in skin temperature following exercise induced heat stress. Copyright © 2014 the American Physiological Society.
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.
Short communication: calf body temperature following chemical disbudding with sedation: effects of milk allowance and supplemental heat.

PubMed

Vasseur, E; Rushen, J; de Passillé, A M

2014-01-01

The use of caustic paste combined with a sedative is one of the least painful methods for disbudding. It is recommended to disbud at as early as 5d of age. However, the sedative xylazine reportedly causes a decrease in core temperature. Furthermore, young calves do not thermoregulate efficiently. We investigated the effects of disbudding calves at 5d of age using caustic paste and xylazine sedation on body temperature, activity, and milk intake of 46 individually housed 5-d-old calves in a 2×2 factorial design, with milk fed at 4.5L/d (low-fed calves) versus 9L/d (high-fed calves), with or without a heat lamp. Body temperature, calf activity (standing time), and barn temperature were monitored continuously using automatic data loggers on the day of, before the day of, and the day after disbudding. All calves were injected intramuscularly with 0.25mL of 2mg/mL xylazine 20min before disbudding (dose: 0.12±0.003mL/kg of BW). We found that the body temperature of 5-d-old calves decreased immediately after the injection of the sedative xylazine. The body temperature of calves decreased 0.9±0.09°C and it took 3.8±0.32h to climb back to the preinjection body temperature. Calves that were fed the lower amount of milk, received a higher dose of xylazine (mL/kg BW), or were disbudded in a colder environment were more affected by body temperature variations (lower and longest decrease in body temperature and higher magnitude). Calf activity recovery followed the pattern of body temperature recovery. Milk allowance and supplemental heat did not help enhance recovery during the 6h following the procedure. The disbudding procedure did not affect milk intake but calves with less body temperature decrease or kept in a warmer environment drank more milk following disbudding. Low-fed calves were overall more affected by the procedure than high-fed calves during the disbudding day and the following day (greater decrease in body temperature and drank less in the colder environment). Providing a high-milk diet is a suitable option to help mitigate calf discomfort due to the disbudding procedure, whereas using a heat lamp does not seem to help, at least in a mildly cold winter. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Oral administration of γ-aminobutyric acid affects heat production in a hot environment in resting humans.

PubMed

Miyazawa, Taiki; Kawabata, Takashi; Okazaki, Kazunobu; Suzuki, Takashi; Imai, Daiki; Hamamoto, Takeshi; Matsumura, Shinya; Miyagawa, Toshiaki

2012-02-29

Central administration of γ-amino butyric acid (GABA) induces lower body temperature in animals in hot ambient air. However, it is still unknown whether oral GABA administration affects temperature regulation at rest in a hot environment in humans. Therefore, in the present study, we specifically hypothesized that systemic administration of GABA in humans would induce hypothermia in a hot environment and that this response would be observed in association with decreased heat production. Eight male participants drank a 200-ml sports drink with 1 g of GABA (trial G) or without GABA (trial C), then rested for 30 minutes in a sitting position in a hot environment (ambient air temperature 33°C, relative humidity 50%). We found that changes in esophageal temperature from before drinking the sports drink were lower in trial G than in trial C (-0.046 ± 0.079°C vs 0.001 ± 0.063°C; P < 0.05), with lower heat production calculated by oxygen consumption (41 ± 5 W/m2 vs 47 ± 8 W/m2; P < 0.05). In this study, we have demonstrated that a single oral administration of GABA induced a larger decrease in body core temperature compared to a control condition during rest in a hot environment and that this response was concomitant with a decrease in total heat production.
Real-Time Thermographic-Phosphor-Based Temperature Measurements of Thermal Barrier Coating Surfaces Subjected to a High-Velocity Combustor Burner Environment

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.; Jenkins, Thomas P.; Allison, Stephen W.; Cruzen, Scott; Condevaux, J. J.; Senk, J. R.; Paul, A. D.

2011-01-01

Surface temperature measurements were conducted on metallic specimens coated with an yttria-stabilized zirconia (YSZ) thermal barrier coating (TBC) with a YAG:Dy phosphor layer that were subjected to an aggressive high-velocity combustor burner environment. Luminescence-based surface temperature measurements of the same TBC system have previously been demonstrated for specimens subjected to static furnace or laser heating. Surface temperatures were determined from the decay time of the luminescence signal of the YAG:Dy phosphor layer that was excited by a pulsed laser source. However, the furnace and laser heating provides a much more benign environment than that which exists in a turbine engine, where there are additional challenges of a highly radiant background and high velocity gases. As the next step in validating the suitability of luminescence-based temperature measurements for turbine engine environments, new testing was performed where heating was provided by a high-velocity combustor burner rig at Williams International. Real-time surface temperature measurements during burner rig heating were obtained from the decay of the luminescence from the YAG:Dy surface layer. The robustness of several temperature probe designs in the sonic velocity, high radiance flame environment was evaluated. In addition, analysis was performed to show whether the luminescence decay could be satisfactorily extracted from the high radiance background.
1-km Global Anthropogenic Heat Flux Database for Urban Climate Studies

NASA Astrophysics Data System (ADS)

Dong, Y.; Varquez, A. C. G.; Kanda, M.

2016-12-01

Among various factors contributing to warming in cities, anthropogenic heat emission (AHE), defined by heat fluxes arising from human consumption of energy, has the most obvious influence. Despite this, estimation of the AHE distribution is challenging and assumed almost uniform in investigations of the regional atmospheric environment. In this study, we introduce a top-down method for estimating a global distribution of AHE (see attachment), with a high spatial resolution of 30 arc-seconds and temporal resolution of 1 hour. Annual average AHE was derived from human metabolic heating and primary energy consumption, which was further divided into three components based on consumer sector: heat loss, heat emissions from industrial-related sectors and heat emissions from commercial, residential and transport sectors (CRT). The first and second components were equally distributed throughout the country and populated areas, respectively. Bulk AHE from the CRT was proportionally distributed using a global population dataset with a nighttime lights adjustment. An empirical function to estimate monthly fluctuations of AHE based on monthly temperatures was derived from various city measurements. Finally, a global AHE database was constructed for the year 2013. Comparisons between our proposed AHE and other existing datasets revealed that a problem of AHE underestimation at central urban areas existing in previous top-down models was significantly mitigated by the nighttime lights adjustment. A strong agreement in the monthly profiles of AHE between our database and other bottom-up datasets further proved the validity of our current methodology. Investigations of AHE in the 29 largest urban agglomerations globally highlighted that the share of heat emissions from CRT sectors to the total AHE at the city level was 40-95%, whereas the share of metabolic heating varied closely depending on the level of economic development in the city. Incorporation of our proposed AHE data into climate models will provide a more realistic representation of urban atmospheric environment, leading to a deeper understanding of urban climate change. Acknowledgment: This research was supported by the Environment Research and Technology Development Fund (S-14) of the Ministry of the Environment, Japan
Diversity in transcripts and translational pattern of stress proteins in marine extremophiles.

PubMed

Ambily Nath, I V; Loka Bharathi, P A

2011-03-01

Extremophiles occur in a diverse range of habitats, from the frigid waters of Antarctic to the superheated plumes of hydrothermal vents. Their in-depth study could provide important insights into the biochemical, ecological and evolutionary aspects of marine microbes. The cellular machinery of such extreme-lovers could be highly flexible to cope with such harsh environments. Extreme conditions of temperature, pressure, salinity, pH, oxidative stress, radiation, etc., above the physiological tolerance level can disrupt the natural conformation of proteins in the cell. The induction of stress proteins (heat/cold shock proteins/salt stress proteins/pressure-induced proteins) plays a vital role in the acclimatization of extremophiles. The present review focuses on the in vitro studies conducted on the transcripts and translational pattern of stress proteins in extremophiles. Though some proteins are unique, a commonality in stress resistance mechanism has been observed, for example, the universal occurrence of HSP60, 70 and the expression of metabolic and DNA repair proteins. The review highlights that among all the stressful conditions, salt/osmotic stress evokes the expression of highest number of transcripts/proteins while psychrophilic condition the least.
Genome-Wide Identification and Expression Profiling Analysis of the Xyloglucan Endotransglucosylase/Hydrolase Gene Family in Tobacco (Nicotiana tabacum L.).

PubMed

Wang, Meng; Xu, Zongchang; Ding, Anming; Kong, Yingzhen

2018-05-24

Xyloglucan endotransglucosylase/hydrolase genes ( XTHs ) encode enzymes required for the reconstruction and modification of xyloglucan backbones, which will result in changes of cell wall extensibility during growth. A total of 56 NtXTH genes were identified from common tobacco, and 50 cDNA fragments were verified by PCR amplification. The 56 NtXTH genes could be classified into two subfamilies: Group I/II and Group III according to their phylogenetic relationships. The gene structure, chromosomal localization, conserved protein domains prediction, sub-cellular localization of NtXTH proteins and evolutionary relationships among Nicotiana tabacum , Nicotiana sylvestrisis , Nicotiana tomentosiformis , Arabidopsis , and rice were also analyzed. The NtXTHs expression profiles analyzed by the TobEA database and qRT-PCR revealed that NtXTHs display different expression patterns in different tissues. Notably, the expression patterns of 12 NtXTHs responding to environment stresses, including salinity, alkali, heat, chilling, and plant hormones, including IAA and brassinolide, were characterized. All the results would be useful for the function study of NtXTHs during different growth cycles and stresses.
Foraging Activity Pattern Is Shaped by Water Loss Rates in a Diurnal Desert Rodent.

PubMed

Levy, Ofir; Dayan, Tamar; Porter, Warren P; Kronfeld-Schor, Noga

2016-08-01

Although animals fine-tune their activity to avoid excess heat, we still lack a mechanistic understanding of such behaviors. As the global climate changes, such understanding is particularly important for projecting shifts in the activity patterns of populations and communities. We studied how foraging decisions vary with biotic and abiotic pressures. By tracking the foraging behavior of diurnal desert spiny mice in their natural habitat and estimating the energy and water costs and benefits of foraging, we asked how risk management and thermoregulatory requirements affect foraging decisions. We found that water requirements had the strongest effect on the observed foraging decisions. In their arid environment, mice often lose water while foraging for seeds and cease foraging even at high energetic returns when water loss is high. Mice also foraged more often when energy expenditure was high and for longer times under high seed densities and low predation risks. Gaining insight into both energy and water balance will be crucial to understanding the forces exerted by changing climatic conditions on animal energetics, behavior, and ecology.
Europa, tidally heated oceans, and habitable zones around giant planets.

PubMed

Reynolds, R T; McKay, C P; Kasting, J F

1987-01-01

Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. In our own solar system, Europa, one of the Galilean satellites of Jupiter, could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of Aeons and in which life could perhaps evolve. We define a zone around a giant planet in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In our solar system, this radiatively-heated habitable zone contains the Earth.
Testing and Failure Mechanisms of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.; Hawkins-Reynolds, Ebony

2010-01-01

Phase change materials (PCM) may be useful for thermal control systems that involve cyclical heat loads or cyclical thermal environments such as Low Earth Orbit (LEO) and Low Lunar Orbit (LLO). Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. One advantage that PCM s have over evaporators in this scenario is that they do not use a consumable. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents the results of testing that occurred from March through September of 2010 and builds on testing that occurred during the previous year.
Testing and Failure Mechanisms of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.; Hawkins-Reynolds, Ebony

2011-01-01

Phase change materials (PCM) may be useful for thermal control systems that involve cyclical heat loads or cyclical thermal environments such as specific spacecraft orientations in Low Earth Orbit (LEO) and low beta angle Low Lunar Orbit (LLO). Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. One advantage that PCM s have over evaporators in this scenario is that they do not use a consumable. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents the results of testing that occurred from March through September of 2010 and builds on testing that occurred during the previous year.
The comparative analysis of heat transfer efficiency in the conditions of formation of ash deposits in the boiler furnaces, with taking into account the crystallization of slag during combustion of coal and water-coal fuel

NASA Astrophysics Data System (ADS)

Salomatov, V. V.; Kuznetsov, G. V.; Syrodoy, S. V.

2017-11-01

The results of the numerical simulation of heat transfer from the combustion products of coal and coal-water fuels (CWF) to the internal environment. The mathematical simulation has been carried out on the sample of the pipe surfaces of the combustion chamber of the boiler unit. The change in the characteristics of heat transfer (change of thermochemical characteristics) in the conditions of formation of the ash deposits have been taken into account. According to the results of the numerical simulation, the comparative analysis of the efficiency of heat transfer has been carried out from the furnace environment to the inside pipe coolant (water, air, or water vapor) from the combustion of coal and coal-water fuels. It has been established that, in the initial period of the boiler unit operation during coal fuel combustion the efficiency of heat transfer from the combustion products of the internal environment is higher than when using CWF. The efficiency of heat transfer in CWF combustion conditions is more at large times (τ≥1.5 hours) of the boiler unit. A significant decrease in heat flux from the combustion products to the inside pipe coolant in the case of coal combustion compared to CWF has been found. It has been proved that this is due primarily to the fact that massive and strong ash deposits are formed during coal combustion.
Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, T.T.; Blake, R.D.

1987-09-22

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate. 2 figs.
Modeling the pyrolysis study of non-charring polymers under reduced pressure environments

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

NASA Astrophysics Data System (ADS)

Elashnikov, Roman; Fitl, Premysl; Svorcik, Vaclav; Lyutakov, Oleksiy

2017-02-01

Laser heating and Marangoni flow result in the formation of surface structures with different geometries and shape on thin polymer films. By laser beam irradiation combined with a sample movement the solid polymethylmethacrylate (PMMA) films are heated and undergo phase transition which leads to a material flow. Since the laser beam has a non-linear distribution of energy, the PMMA film is heated inhomogeneously and a surface tension gradient in a lateral direction is introduced. During this procedure additional phenomena such as "reversible" or cyclic polymer flow also take place. The careful choice of experimental conditions enables the preparation of patterns with sophisticated geometries and with hierarchical pattern organization. Depending on initial PMMA film thickness and speed of the sample movement line arrays are created, which can subsequently be transformed into the crimped lines or system of circular holes. In addition, the introduction of a constant acceleration in the sample movement or a laser beam distortion enables the preparation of regularly crimped lines, ordered hexagonal holes or overlapped plates.
Enhanced boiling in microchannels due to recirculation induced by repeated saw-toothed cross-sectional geometry

NASA Astrophysics Data System (ADS)

Gao, Le; Bhavnani, Sushil H.

2017-10-01

A saw-toothed shaped microchannel heat sink is investigated for enhancing flow boiling heat transfer. Tests are conducted at mass fluxes of 444-1776 kg/m2 s and an inlet subcooling of 15 °C. The effects of channel geometry on boiling curves, flow patterns, pressure drops, and heat transfer coefficient are discussed in this letter. It is found that heat transfer performance is enhanced by up to 50% especially at heat flux levels associated with the current generation of microprocessors.

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