Magnetic transition in Y-site doped multiferroic YMnO3

NASA Astrophysics Data System (ADS)

Thakur, Rajesh K.; Thakur, Rasna; Gaur, N. K.

2016-05-01

We have synthesized polycrystalline hexagonal Y1-xSrxMnO3 (x=0.02, 0.1) compounds by using conventional solid state reaction method. The detailed structural investigations are carried out by using XRD studies which reveals the single phase formation of the reported compounds with hexagonal structure and space group P63cm (JCPDS: 25-1079). Further the XRD data of reported compounds were analyzed by RIETVELD (FULLPROFF) method which shows the decrease in the lattice parameter with increasing concentration of divalent strontium to Y-site. The observed pointed kinks in the specific heat study are indicative of the probable coupling in between the electric and magnetic orders in this class of materials. The reported systematic specific heat studies shows that the antiferromagnetic (AFM) transition temperature (TN) shifts to higher value with increasing concentration of Sr2+ ion in the YMnO3 compound which is attributed to the enhanced lattice contribution to the specific heat in the this compound. The present compound shows the independence of specific heat and magnetic transition temperature with applied magnetic field of 8T and 12T.

Impact of heat processing on the detection of the major shellfish allergen tropomyosin in crustaceans and molluscs using specific monoclonal antibodies.

PubMed

Kamath, Sandip D; Abdel Rahman, Anas M; Komoda, Toshikazu; Lopata, Andreas L

2013-12-15

The major heat-stable shellfish allergen, tropomyosin, demonstrates immunological cross-reactivity, making specific differentiation of crustaceans and molluscs for food labelling very difficult. The aim of this study was to evaluate the application of allergen-specific monoclonal antibodies in differential detection of shellfish-derived tropomyosin in 11 crustacean and 7 mollusc species, and to study the impact of heating on its detection. Cross-reactive tropomyosin was detected in all crustacean species, with partial detection in molluscs: mussels, scallops and snails but none in oyster, octopus and squid. Furthermore, we have demonstrated that heating of shellfish has a profound effect on tropomyosin detection. This was evident by the enhanced recognition of multiple tropomyosin variants in the analysed shellfish species. Specific monoclonal antibodies, targetting the N-terminal region of tropomyosin, must therefore be developed to differentiate tropomyosins in crustaceans and molluscs. This can help in correct food labelling practices and thus protection of consumers. Copyright © 2013 Elsevier Ltd. All rights reserved.

A study on specific heat capacities of Li-ion cell components and their influence on thermal management

NASA Astrophysics Data System (ADS)

Loges, André; Herberger, Sabrina; Seegert, Philipp; Wetzel, Thomas

2016-12-01

Thermal models of Li-ion cells on various geometrical scales and with various complexity have been developed in the past to account for the temperature dependent behaviour of Li-ion cells. These models require accurate data on thermal material properties to offer reliable validation and interpretation of the results. In this context a thorough study on the specific heat capacities of Li-ion cells starting from raw materials and electrode coatings to representative unit cells of jelly rolls/electrode stacks with lumped values was conducted. The specific heat capacity is reported as a function of temperature and state of charge (SOC). Seven Li-ion cells from different manufactures with different cell chemistry, application and design were considered and generally applicable correlations were developed. A 2D thermal model of an automotive Li-ion cell for plug-in hybrid electric vehicle (PHEV) application illustrates the influence of specific heat capacity on the effectivity of cooling concepts and the temperature development of Li-ion cells.

Origin of two maxima in specific heat in enthalpy relaxation under thermal history composed of cooling, annealing, and heating.

PubMed

Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

2016-12-01

The origin of two maxima in specific heat observed at the higher and the lower temperatures in the glass-transition region in the heating process has been studied for polymethyl methacrylate and polyvinyl chloride using differential scanning calorimetry, and the calculation was done using the phenomenological model equation under a thermal history of the typical annealing experiment composed of cooling, annealing, and heating. The higher maximum is observed above the glass-transition temperature, and it remains almost unchanged independent of annealing time t_{a}, while the lower one is observed above an annealing temperature T_{a} and shifts toward the higher one, increasing its magnitude with t_{a}. The analysis by the phenomenological model equation proposed in order to interpret the memory effect in the glassy state clarifies that under a typical annealing history, two maxima in specific heat essentially appear. The shift of the lower maximum toward higher temperatures from above T_{a} is caused by an increase in the amount of relaxation during annealing with t_{a}. The annealing temperature and the amount of relaxation during annealing play a major role in the determination of the number of maxima in the specific heat.

Estimation of Phonon and Carrier Thermal Conductivities for Bulk Thermoelectric Materials Using Transport Properties

NASA Astrophysics Data System (ADS)

Otsuka, Mioko; Homma, Ryoei; Hasegawa, Yasuhiro

2017-05-01

The phonon and carrier thermal conductivities of thermoelectric materials were calculated using the Wiedemann-Franz law, Boltzmann equation, and a method we propose in this study called the Debye specific heat method. We prepared polycrystalline n-type doped bismuth telluride (BiTe) and bismuth antimony (BiSb) bulk alloy samples and measured six parameters (Seebeck coefficient, resistivity, thermal conductivity, thermal diffusivity, magneto-resistivity, and Hall coefficient). The carrier density and mobility were estimated for calculating the carrier thermal conductivity by using the Boltzmann equation. In the Debye specific heat method, the phonon thermal diffusivity, and thermal conductivity were calculated from the temperature dependence of the effective specific heat by using not only the measured thermal conductivity and Debye model, but also the measured thermal diffusivity. The carrier thermal conductivity was also evaluated from the phonon thermal conductivity by using the specific heat. The ratio of carrier thermal conductivity to thermal conductivity was evaluated for the BiTe and BiSb samples, and the values obtained using the Debye specific heat method at 300 K were 52% for BiTe and <5.5% for BiSb. These values are either considerably larger or smaller than those obtained using other methods. The Dulong-Petit law was applied to validate the Debye specific heat method at 300 K, which is significantly greater than the Debye temperature of the BiTe and BiSb samples, and it was confirmed that the phonon specific heat at 300 K has been accurately reproduced using our proposed method.

Thermal expansion and specific heat of La1-xTexCoO3

NASA Astrophysics Data System (ADS)

Thakur, Rasna; Thakur, Rajesh K.; Gaur, N. K.

2018-05-01

We present the specific heat and thermal expansion of La1-xTexCoO3 family using Modified Rigid Ion Model (MRIM). The effect of Te doping on the thermal and cohesive properties have been studied by an atomistic approach. The Debye temperature of these perovskite materials is also predicted. The effect of Tellurium doping on lattice specific heat (C), thermal expansion (α) of La1-xTexCoO3 (x= 0.05-0.25) as a function of temperature (1K≤T≤1000K) is reported probably for the first time.

Characterization and Thermal Properties of Nitrate Based Molten Salt for Heat Recovery System

NASA Astrophysics Data System (ADS)

Faizal Tukimon, Mohd; Muhammad, Wan Nur Azrina Wan; Nor Annuar Mohamad, Md; Yusof, Farazila

2017-10-01

Molten salt can acts like a storage medium or heat transfer fluid in heat recovery system. Heat transfer fluid is a fluid that has the capability to deliver heat this one side to another while heat recovery system is a system that transfers heat to produce energy. This studies shows about determining the new formulation of different molten nitrate/nitrite salts consisting of LiNO3, KNO2, KNO3 and NaNO2 that give a low temperature of melting point and high average specific heat capacity. Mixed alkaline molten nitrate/nitrite salt can act as a heat transfer fluid due to their advantageous in terms of its properties that feasible in heat recovery system such as high specific heat capacity, low vapour pressure, low cost and wide range of temperature in its application. The mixing of these primary substances will form a new line of quaternary nitrate salt (LiNO3 - KNO2 - KNO3 - NaNO2). The quaternary mixture was heated inside the box furnace at 150°C for four hours and rose up the temperature to 400°C for eight hours to homogenize the mixture. Through heating process, the elements of nitrate/nitrite base were mixed completely. The temperature was then reduced to 115°C for several hours before removing the mixture from the furnace. The melting point of each sample were testified by using thermal gravimetric analysis, TGA/DTA and experiment of determining the specific heat capacity were conducted by using Differential Scanning Calorimeter, DSC. From the result, it is found that the melting point Sample 1 with percentage of weightage (25.4wt% of LiNO3, 33.8wt% of KNO2, 20.7wt% of KNO3 and 20.1wt% of NaNO2) is 94.4°C whereas the average specific heat capacity was 1.0484/g°C while for Sample 3 with percentages of weightage (30.0wt% of LiNO3, 50.2wt% of KNO2, 3.1wt% of KNO3 and 16.7wt% of NaNO2), the melting point is 86.1°C with average specific heat capacity of 0.7274 J/g°C. In the nut shell, the quaternary mixture salts had been a good mixture with good thermal properties that low in melting point and have high specific heat capacity which could be a potential heat transfer fluid in heat recovery application.

Better latent heat and specific heat of stearic acid with magnetite/graphene nanocomposite addition for thermal storage application

NASA Astrophysics Data System (ADS)

Andiarto, R.; Nuryadin, M. K.; Taufik, A.; Saleh, R.

2017-04-01

In our previous study, the addition of Magnetite (Fe3O4) into Stearic acid (Sa) as an organic phase change material (PCM) shows an enhancement in the latent heat for thermal energy storage applications. The latent heat of the PCM can also be increased by adding graphene material. Therefore, in this research, the thermal properties of Sa have been studied by the sonication method for several different concentrations of Fe3O4/Graphene nanocomposite additions. The structural properties of all of the samples were observed by X-Ray diffraction (XRD). Melting-solidifying behavior and specific heat value were measured by differential scanning calorimetry (DSC). The thermal degradation process of all samples was investigated by thermogravimetric analysis (TGA). Based on the DSC results, the presence of Fe3O4/Graphene in the Sa enhances the latent heat up to 20%. The specific heat value of the mixture was also found to be increased as the concentration of Fe3O4/Graphene to Sa increased. The TGA results show a lowered thermal degradation process of the Sa by the addition of the Fe3O4/Graphene which indicates a higher thermal stability of the mixture. In conclusion, the results demonstrate that the addition of Fe3O4/Graphene to Sa improves both the sensible heat and the latent heat of the mixture which are very important for thermal energy storage applications

Heat shock protein 60 expression in heart, liver and kidney of broilers exposed to high temperature.

PubMed

Yan, Jianyan; Bao, Endong; Yu, Jimian

2009-06-01

The objective of this study was to investigate the expression and localization of HSP60 in the heart, liver, and kidney of acutely heat-stressed broilers at various stressing times. The plasma creatine kinase (CK) and glutamic pyruvic transaminase (GPT) concentrations statistic increased following heat stress. After 2h of heat stress, the tissues showed histopathological changes. Hsp60 expressed mainly in the cytoplasm of parenchyma cells heat stress. The intensity of the cytoplasmic staining varied and exhibited an organ-specific distribution pattern. Hsp60 levels in the hearts of heat-stressed chickens gradually increased at 1h (p<0.05) and peaked (p<0.05) at 5h; Hsp60 levels in the liver gradually decreased at 3h (p<0.05); Hsp60 levels in the kidney had no fluctuation. It is suggested that Hsp60 expression is tissue-specific and this may be linked to tissue damage in response to heat stress. The Hsp60 level is distinct in diverse tissues, indicating that Hsp60 may exert its protective effect by a tissue- and time-specific mechanism.

Heat Treatment of Tantalum and Niobium Powders Prepared by Magnesium-Thermic Reduction

NASA Astrophysics Data System (ADS)

Orlov, V. M.; Prokhorova, T. Yu.

2017-11-01

Changes in the specific surface area and porous structure of tantalum and niobium powders, which were prepared by magnesium-thermic reduction of Ta2O5, Mg4Ta2O9, and Mg4Nb2O9 oxide compounds and subjected to heat treatments at temperatures of 600-1500°C, have been studied. It is noted that, owing to the mesoporous structure of the magnesium-thermic powders, the decrease in the surface area during heat treatment, first of all, is related to a decrease in the amount of pores less than 10 nm in size. The heat treatment of a reacting mass is shown to allow us to correct the specific surface area of the powder without any increase in the oxygen content in it. Data on the effect of heat treatment conditions on the specific charge of capacitor anodes are reported.

Thermophysical properties of LiCoO₂-LiMn₂O₄ blended electrode materials for Li-ion batteries.

PubMed

Gotcu, Petronela; Seifert, Hans J

2016-04-21

Thermophysical properties of two cathode types for lithium-ion batteries were measured by dependence on temperature. The cathode materials are commercial composite thick films containing LiCoO2 and LiMn2O4 blended active materials, mixed with additives (binder and carbon black) deposited on aluminium current collector foils. The thermal diffusivities of the cathode samples were measured by laser flash analysis up to 673 K. The specific heat data was determined based on measured composite specific heat, aluminium specific heat data and their corresponding measured mass fractions. The composite specific heat data was measured using two differential scanning calorimeters over the temperature range from 298 to 573 K. For a comprehensive understanding of the blended composite thermal behaviour, measurements of the heat capacity of an additional LiMn2O4 sample were performed, and are the first experimental data up to 700 K. Thermal conductivity of each cathode type and their corresponding blended composite layers were estimated from the measured thermal diffusivity, the specific heat capacity and the estimated density based on metallographic methods and structural investigations. Such data are highly relevant for simulation studies of thermal management and thermal runaway in lithium-ion batteries, in which the bulk properties are assumed, as a common approach, to be temperature independent.

Magnetic transition in Y-site doped multiferroic YMnO{sub 3}

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

Thakur, Rajesh K., E-mail: thakur.rajesh2009@gmail.com; Thakur, Rasna, E-mail: rasnathakur@yahoo.com; Gaur, N. K., E-mail: srl-nkgaur@yahoo.co.in

2016-05-06

We have synthesized polycrystalline hexagonal Y{sub 1-x}Sr{sub x}MnO{sub 3} (x=0.02, 0.1) compounds by using conventional solid state reaction method. The detailed structural investigations are carried out by using XRD studies which reveals the single phase formation of the reported compounds with hexagonal structure and space group P6{sub 3}cm (JCPDS: 25-1079). Further the XRD data of reported compounds were analyzed by RIETVELD (FULLPROFF) method which shows the decrease in the lattice parameter with increasing concentration of divalent strontium to Y-site. The observed pointed kinks in the specific heat study are indicative of the probable coupling in between the electric and magneticmore » orders in this class of materials. The reported systematic specific heat studies shows that the antiferromagnetic (AFM) transition temperature (T{sub N}) shifts to higher value with increasing concentration of Sr{sup 2+} ion in the YMnO{sub 3} compound which is attributed to the enhanced lattice contribution to the specific heat in the this compound. The present compound shows the independence of specific heat and magnetic transition temperature with applied magnetic field of 8T and 12T.« less

Thermodynamic properties of the S =1 /2 twisted triangular spin tube

NASA Astrophysics Data System (ADS)

Ito, Takuya; Iino, Chihiro; Shibata, Naokazu

2018-05-01

Thermodynamic properties of the twisted three-leg spin tube under magnetic field are studied by the finite-T density-matrix renormalization group method. The specific heat, spin, and chiral susceptibilities of the infinite system are calculated for both the original and its low-energy effective models. The obtained results show that the presence of the chirality is observed as a clear peak in the specific heat at low temperature and the contribution of the chirality dominates the low-temperature part of the specific heat as the exchange coupling along the spin tube decreases. The peak structures in the specific heat, spin, and chiral susceptibilities are strongly modified near the quantum phase transition where the critical behaviors of the spin and chirality correlations change. These results confirm that the chirality plays a major role in characteristic low-energy behaviors of the frustrated spin systems.

Generalization of experimental data on heat transfer in permeable shells made of porous reticular materials

NASA Astrophysics Data System (ADS)

Polyakov, A. F.; Strat'ev, V. K.; Tret'yakov, A. F.; Shekhter, Yu. L.

2010-06-01

Heat transfer from six samples of porous reticular material to cooling gas (air) at small Reynolds numbers is experimentally studied. The specific features pertinent to heat transfer essentially affected by longitudinal heat conductivity along gas flow are analyzed. The experimental results are generalized in the form of dimensionless empirical relations.

[An experimental study of effects of active-heating-system for extravehicular spacesuit gloves on working performance].

PubMed

Ding, Li; Han, Long-zhu; Yang, Chun-xin; Yang, Feng; Yuan, Xiu-gan

2005-02-01

To observe the effects of active heating system for spacesuit gloves on extravehicular working performance. After analyzing the factors with gloves influence on the working performance, the effects of active heating system for gloves were studied experimentally with aspects to fatigue, hand strength, dexterity and tactile sensing. 1) Heating-system had not influence to grip; 2) Heating-system had 17% influence to fatigue except specific person; 3) Nut assembly and nipping pin showed that heating-system had little influence to dexterity; 4) Apperceiving shape of object and two-point distance showed heating-system had little influence to tactility. The active heating method is rational and has little influence on working performance.

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

PubMed

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

2014-05-01

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

Novel specific heat and magnetoresistance behavior of Tb0.5Ho0.5Mn2Si2

NASA Astrophysics Data System (ADS)

Pandey, Swati; Siruguri, V.; Rawat, R.

2018-04-01

In this report, we study temperature dependent heat capacity and electrical resistance of Tb1-xHoxMn2Si2 (x = 0.5). Two successive low temperature magnetic transitions T1 (˜15 K) and T2 (˜25 K) are observed from both measurements. Anomalous rise in heat capacity at low temperatures is ascribed to the nuclear Schottky effect. Sommerfeld coefficient (γ), Debye temperature (θD) and density of states at Fermi level N(EF) is calculated from the zero field specific heat data. We observe 4f contribution to heat capacity from T1 to 100K, which is attributed to crystal field effect. In the electrical transport study, application of the magnetic field shows a substantial change around the ordering temperature of rare earth moment resulting in large positive magnetoresistance of about 20% with field change of 6T.

Limitations and possibilities of AC calorimetry in diamond anvil cells

NASA Astrophysics Data System (ADS)

Geballe, Zachary; Colins, Gilbert; Jeanloz, Raymond

2013-06-01

Dynamic laser heating or internal resistive heating could allow for the determination of calorimetric properties of samples that are held statically at high pressure. However, the highly non-adiabatic environment of high-pressure cells presents several challenges. Here, we quantify the errors in AC calorimetry measurements using laser heating or internal resistive heating inside diamond anvil cells, summarize the equipment requirements of supplying sufficient power modulated at a high enough frequency to measure specific heats and latent heats of phase transitions, and propose two new experiments in internally-heated diamond anvil cells: an absolute measurement of specific heat (with ~10% uncertainty) of non-magnetic metals using resistive heating at ~10 MHz, and a relative measurement to detect changes in either the specific heat of metals or in the effusively (the product of specific heat, density and thermal conductivity) of an insulator.

Experimental study on performance of outdoor ground materials in aspect of surface temperature by constant field experiment in subtropical climate city

NASA Astrophysics Data System (ADS)

Xi, T. Y.; Ding, J. H.; Lv, X. W.; Lei, Y. S.

2018-06-01

In order to create a comfortable building thermal environment, it is important to study the outdoor ground materials performance. In this article, we carried out a constant field experiment in Guangzhou, China, studying on the variations of the surface temperature of three common outdoor building materials: concrete, pavement and grass. We put the equipment on six experiment points respectively to measure the ground surface temperature constantly. The result shows that because of the specific heat capacity, both concrete and pavement have an obvious time delay during their temperature decrease when the grass ground has almost no time delay. And when in the same conditions (exposed to sunlight all day), the material with a low specific heat capacity has a more sensitive variation in temperature. The lower the specific capacity is, the steeper the variation trend of the surface temperature will be. So compared with concrete, the pavement brick ground with a low specific heat capacity has a higher surface temperature in daytime and a lower temperature in the late night time. When in different conditions (different time exposed to sunlight), the temperature value is proportional to the time exposed to the sunlight between the same materials. The concrete exposed to sunlight all day has the highest temperature when the shaded one has the lowest. This experiment reveals that both specific heat capacity and the exposed time to sunlight has a strong influence on the surface temperature of outdoor materials. In subtropical region, the materials with a higher specific heat capacity and a less time exposed to sunlight may be more beneficial to the building thermal environment.

What weather variables are important in predicting heat-related mortality? A new application of statistical learning methods

PubMed Central

Zhang, Kai; Li, Yun; Schwartz, Joel D.; O'Neill, Marie S.

2014-01-01

Hot weather increases risk of mortality. Previous studies used different sets of weather variables to characterize heat stress, resulting in variation in heat-mortality- associations depending on the metric used. We employed a statistical learning method – random forests – to examine which of various weather variables had the greatest impact on heat-related mortality. We compiled a summertime daily weather and mortality counts dataset from four U.S. cities (Chicago, IL; Detroit, MI; Philadelphia, PA; and Phoenix, AZ) from 1998 to 2006. A variety of weather variables were ranked in predicting deviation from typical daily all-cause and cause-specific death counts. Ranks of weather variables varied with city and health outcome. Apparent temperature appeared to be the most important predictor of heat-related mortality for all-cause mortality. Absolute humidity was, on average, most frequently selected one of the top variables for all-cause mortality and seven cause-specific mortality categories. Our analysis affirms that apparent temperature is a reasonable variable for activating heat alerts and warnings, which are commonly based on predictions of total mortality in next few days. Additionally, absolute humidity should be included in future heat-health studies. Finally, random forests can be used to guide choice of weather variables in heat epidemiology studies. PMID:24834832

Specific heat of FeSe: Two gaps with different anisotropy in superconducting state

NASA Astrophysics Data System (ADS)

Muratov, A. V.; Sadakov, A. V.; Gavrilkin, S. Yu.; Prishchepa, A. R.; Epifanova, G. S.; Chareev, D. A.; Pudalov, V. M.

2018-05-01

We present detailed study of specific heat of FeSe single crystals with critical temperature Tc = 8.45 K at 0.4 - 200 K in magnetic fields 0 - 9 T. Analysis of the electronic specific heat at low temperatures shows the coexistence of isotropic s-wave gap and strongly anisotropic extended s-wave gap without nodes. It was found two possibilities of superconducting gap parameters which give equally description of experimental data: (i) two gaps with approximately equal amplitudes and weight contribution to specific heat: isotropic Δ1 = 1.7 meV (2Δ1 /kBTc =4.7) and anisotropic gap with the amplitude Δ2max = 1.8 meV (2 Δ2max /kBTc =4.9 and anisotropy parameter m = 0.85); (ii) two gaps with substantially different values: isotropic large gap Δ1 = 1.65 meV (2Δ1 /kBTc = 4.52) and anisotropic small gap Δ2max = 0.75 meV (2Δ2max /kBTc = 2) with anisotropy parameter m = 0.71 . These results are confirmed by the field behavior of the residual electronic specific heat γr.

Plasma vitrification and re-use of non-combustible fiber reinforced plastic, gill net and waste glass.

PubMed

Chu, J P; Chen, Y T; Mahalingam, T; Tzeng, C C; Cheng, T W

2006-12-01

Fiber reinforced plastic (FRP) composite material has widespread use in general tank, special chemical tank and body of yacht, etc. The purpose of this study is directed towards the volume reduction of non-combustible FRP by thermal plasma and recycling of vitrified slag with specific procedures. In this study, we have employed three main wastes such as, FRP, gill net and waste glass. The thermal molten process was applied to treat vitrified slag at high temperatures whereas in the post-heat treatment vitrified slags were mixed with specific additive and ground into powder form and then heat treated at high temperatures. With a two-stage heat treatment, the treated sample was generated into four crystalline phases, cristobalite, albite, anorthite and wollastonite. Fine and relatively high dense structures with desirable properties were obtained for samples treated by the two-stage heating treatment. Good physical and mechanical properties were achieved after heat treatment, and this study reveals that our results could be comparable with the commercial products.

Thermal Property Measurement of Semiconductor Melt using Modified Laser Flash Method

NASA Technical Reports Server (NTRS)

Lin, Bochuan; Zhu, Shen; Ban, Heng; Li, Chao; Scripa, Rosalla N.; Su, Ching-Hua; Lehoczky, Sandor L.

2003-01-01

This study further developed standard laser flash method to measure multiple thermal properties of semiconductor melts. The modified method can determine thermal diffusivity, thermal conductivity, and specific heat capacity of the melt simultaneously. The transient heat transfer process in the melt and its quartz container was numerically studied in detail. A fitting procedure based on numerical simulation results and the least root-mean-square error fitting to the experimental data was used to extract the values of specific heat capacity, thermal conductivity and thermal diffusivity. This modified method is a step forward from the standard laser flash method, which is usually used to measure thermal diffusivity of solids. The result for tellurium (Te) at 873 K: specific heat capacity 300.2 Joules per kilogram K, thermal conductivity 3.50 Watts per meter K, thermal diffusivity 2.04 x 10(exp -6) square meters per second, are within the range reported in literature. The uncertainty analysis showed the quantitative effect of sample geometry, transient temperature measured, and the energy of the laser pulse.

Laboratory Activity: Specific Heat by Change in Internal Energy of Silly Putty

ERIC Educational Resources Information Center

Koser, John

2011-01-01

Students in introductory physics courses often don't study thermodynamics or thermodynamic events. If any thermal physics is taught in introductory courses (e.g., Physics 101 for Liberal Arts Majors), it usually involves the concepts of specific heat and various temperature scales. Seldom are the first and second laws of thermodynamics taught in…

A physical model for evaluating uranium nitride specific heat

NASA Astrophysics Data System (ADS)

Baranov, V. G.; Devyatko, Yu. N.; Tenishev, A. V.; Khlunov, A. V.; Khomyakov, O. V.

2013-03-01

Nitride fuel is one of perspective materials for the nuclear industry. But unlike the oxide and carbide uranium and mixed uranium-plutonium fuel, the nitride fuel is less studied. The present article is devoted to the development of a model for calculating UN specific heat on the basis of phonon spectrum data within the solid state theory.

Mathematical model development and simulation of heat pump fruit dryer

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

Achariyaviriya, S.; Soponronnarit, S.; Terdyothin, A.

2000-01-01

A mathematical model of a heat pump fruit dryer was developed to study the performance of heat pump dryers. Using the moisture content of papaya glace drying, the refrigerant temperature at the evaporator and condenser and the performance, was verified. It was found that the simulated results using closed loop heat pump dryer were close to the experimental results. The criteria for evaluating the performance were specific moisture extraction rate and drying rate. The results showed that ambient conditions affected significantly on the performance of the open loop dryer and the partially closed loop dryer. Also, the fraction of evaporatormore » bypass air affected markedly the performance of all heat pump dryers. In addition, it was found that specific air flow rate and drying air temperature affected significantly the performance of all heat pump dryers.« less

Measurement of temperature-dependent specific heat of biological tissues.

PubMed

Haemmerich, Dieter; Schutt, David J; dos Santos, Icaro; Webster, John G; Mahvi, David M

2005-02-01

We measured specific heat directly by heating a sample uniformly between two electrodes by an electric generator. We minimized heat loss by styrofoam insulation. We measured temperature from multiple thermocouples at temperatures from 25 degrees C to 80 degrees C while heating the sample, and corrected for heat loss. We confirm method accuracy with a 2.5% agar-0.4% saline physical model and obtain specific heat of 4121+/-89 J (kg K)(-1), with an average error of 3.1%.

High temperature heat exchanger studies for applications to gas turbines

NASA Astrophysics Data System (ADS)

Min, June Kee; Jeong, Ji Hwan; Ha, Man Yeong; Kim, Kui Soon

2009-12-01

Growing demand for environmentally friendly aero gas-turbine engines with lower emissions and improved specific fuel consumption can be met by incorporating heat exchangers into gas turbines. Relevant researches in such areas as the design of a heat exchanger matrix, materials selection, manufacturing technology, and optimization by a variety of researchers have been reviewed in this paper. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

Spatial and temporal variation in emergency transport during periods of extreme heat in Japan: A nationwide study.

PubMed

Onozuka, Daisuke; Hagihara, Akihito

2016-02-15

Several studies have reported the burden of climate change on extreme heat-related mortality or morbidity. However, few studies have investigated the spatial and temporal variation in emergency transport during periods of extreme heat on a national scale. Daily emergency ambulance dispatch data from 2007 to 2010 were acquired from all 47 prefectures of Japan. The temporal variability in the relationship between heat and morbidity in each prefecture was estimated using Poisson regression combined with a distributed lag non-linear model and adjusted for time trends. The spatial variability in the heat-morbidity relationships between prefectures was estimated using a multivariate meta-analysis. A total of 5,289,660 emergency transports were reported during the summer months (June through September) within the study period. The overall cumulative relative risk (RR) at the 99th percentile vs. the minimum morbidity percentile was 1.292 (95% CI: 1.251-1.333) for all causes, 1.039 (95% CI: 0.989-1.091) for cardiovascular diseases, and 1.287 (95% CI: 1.210-1.368) for respiratory diseases. Temporal variation in the estimated effects indicated a non-linear relationship, and there were differences in the temporal variations between heat and all-cause and cause-specific morbidity. Spatial variation between prefectures was observed for all causes (Cochran Q test, p<0.001; I(2)=45.8%); however, there was no significant spatial heterogeneity for cardiovascular (Cochran Q test, p=0.054; I(2)=15.1%) and respiratory (Cochran Q test, p=0.681; I(2)=1.0%) diseases. Our nationwide study demonstrated differences in the spatial and temporal variations in the relative risk for all-cause and cause-specific emergency transport during periods of extreme heat in Japan between 2007 and 2010. Our results suggest that public health strategies aimed at controlling heat-related morbidity should be tailored according to region-specific weather conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Electronic and Solid State Sciences Program Summary, FY 1979.

DTIC Science & Technology

1979-01-01

studies of the interaction of the electromagnetic field with heat conducting and electrically non-conducting and conducting polarizable and mag- netizable...Physical Review Letters, 42, 401-404 (1979). 9. "The low temperature electronic specific heat of disordered one dimensional chains", by P. S...technique exploits parallel photoheating and dc electrical- heating experiments. The CO laser hot electron studies have provided information on the

Experimental study of forced convection heat transport in porous media

NASA Astrophysics Data System (ADS)

Pastore, Nicola; Cherubini, Claudia; Rapti, Dimitra; Giasi, Concetta I.

2018-04-01

The present study is aimed at extending this thematic issue through heat transport experiments and their interpretation at laboratory scale. An experimental study to evaluate the dynamics of forced convection heat transfer in a thermally isolated column filled with porous medium has been carried out. The behavior of two porous media with different grain sizes and specific surfaces has been observed. The experimental data have been compared with an analytical solution for one-dimensional heat transport for local nonthermal equilibrium condition. The interpretation of the experimental data shows that the heterogeneity of the porous medium affects heat transport dynamics, causing a channeling effect which has consequences on thermal dispersion phenomena and heat transfer between fluid and solid phases, limiting the capacity to store or dissipate heat in the porous medium.

Study of vibrational modes and specific heat of wurtzite phase of BN

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

Singh, Daljit, E-mail: daljit.jt@gmail.com; Sinha, M. M.

2016-05-06

In these days of nanotechnology the materials like BN is of utmost importance as in hexagonal phase it is among hardest materials. The phonon mode study of the materials is most important factor to find structural and thermodynamcal properties. To study the phonons de launey angular force (DAF) constant model is best suited as it involves many particle interactions. Therefore in this presentation we have studied the lattice dynamical properties and specific heat of BN in wurtzite phase using DAF model. The obtained results are in excellent agreement with existing results.

Negative specific heat of black-holes from fluid-gravity correspondence

NASA Astrophysics Data System (ADS)

Bhattacharya, Swastik; Shankaranarayanan, S.

2017-04-01

Black holes in asymptotically flat space-times have negative specific heat—they get hotter as they loose energy. A clear statistical mechanical understanding of this has remained a challenge. In this work, we address this issue using fluid-gravity correspondence which aims to associate fluid degrees of freedom to the horizon. Using linear response theory and the teleological nature of event horizon, we show explicitly that the fluctuations of the horizon-fluid lead to negative specific heat for a Schwarzschild black Hole. We also point out how the specific heat can be positive for Kerr-Newman or AdS black holes. Our approach constitutes an important advance as it allows us to apply the canonical ensemble approach to study thermodynamics of asymptotically flat black hole space-times.

Changes in cause-specific mortality during heat waves in central Spain, 1975-2008

NASA Astrophysics Data System (ADS)

Miron, Isidro Juan; Linares, Cristina; Montero, Juan Carlos; Criado-Alvarez, Juan Jose; Díaz, Julio

2015-09-01

The relationship between heat waves and mortality has been widely described, but there are few studies using long daily data on specific-cause mortality. This study is undertaken in central Spain and analysing natural causes, circulatory and respiratory causes of mortality from 1975 to 2008. Time-series analysis was performed using ARIMA models, including data on specific-cause mortality and maximum and mean daily temperature and mean daily air pressure. The length of heat waves and their chronological number were analysed. Data were stratified in three decadal stages: 1975-1985, 1986-1996 and 1997-2008. Heat-related mortality was triggered by a threshold temperature of 37 °C. For each degree that the daily maximum temperature exceeded 37 °C, the percentage increase in mortality due to circulatory causes was 19.3 % (17.3-21.3) in 1975-1985, 30.3 % (28.3-32.3) in 1986-1996 and 7.3 % (6.2-8.4) in 1997-2008. The increase in respiratory cause ranged from 12.4 % (7.8-17.0) in the first period, to 16.3 % (14.1-18.4) in the second and 13.7 % (11.5-15.9) in the last. Each day of heat-wave duration explained 5.3 % (2.6-8.0) increase in respiratory mortality in the first period and 2.3 % (1.6-3.0) in the last. Decadal scale differences exist for specific-causes mortality induced by extreme heat. The impact on heat-related mortality by natural and circulatory causes increases between the first and the second period and falls significantly in the last. For respiratory causes, the increase is no reduced in the last period. These results are of particular importance for the estimation of future impacts of climate change on health.

Low-temperature specific heat of the quasi-two-dimensional charge-density wave compound KMo6O17

NASA Astrophysics Data System (ADS)

Wang, Junfeng; Xiong, Rui; Yin, Di; Li, Changzhen; Tang, Zheng; Wang, Ququan; Shi, Jing; Wang, Yue; Wen, Haihu

2006-05-01

Low temperature specific heat (Cp) of quasi-two-dimensional charge-density wave (CDW) compound KMo6O17 has been studied by a relaxation method from 2to48K under zero and 12T magnetic fields. The results show that no specific heat anomaly is found at 16K under both zero and 12T magnetic fields, although an anomaly is clearly observed in the resistivity and magnetoresistance measurements. From the data between 2 and 4K , the density of states at Fermi level is estimated as 0.2eV-1permolecule and the Debye temperature is extracted to be 418K . A bump appearing in Cp/T3 is found between 4 and 48K centered around 12.5-15K , indicating that the phason excitations contribute to the total specific heat similarly as in quasi-one-dimensional CDW conductors. Using a modified Debye model, a pinning frequency of 0.73THz for KMo6O17 is estimated from the phason contribution.

Experimental study of high-temperature properties of zirconium carbide as a protective material for nuclear power and aerospace technologies (from 2000 to 5000 K)

NASA Astrophysics Data System (ADS)

Savvatimskiy, A. I.; Onufriev, S. V.; Muboyadzhyan, S. A.; Seredkin, N. N.

2017-11-01

The temperature dependences of the thermal and electro physical properties of the zirconium carbide ZrC + C and ZrCa0.95 were studied in the temperature range 2000-5000 K. The Zr+C specimens were in the form of thin layers sputtered on quarts substrate and ZrC0.95 specimens were in the form of plates cut off from the sintered block. The properties are measured: temperature and heat of fusion, enthalpy, specific heat and resistivity, referred to the initial dimensions. A steep increase in the specific heat of these substances before melting and a sharp decrease after melting were observed at a heating rate of ∼ 108 K/s, which is possibly due to the formation of Frenkel pair defects in the specimens.

The Heat Is on: An Inquiry-Based Investigation for Specific Heat

ERIC Educational Resources Information Center

Herrington, Deborah G.

2011-01-01

A substantial number of upper-level science students and practicing physical science teachers demonstrate confusion about thermal equilibrium, heat transfer, heat capacity, and specific heat capacity. The traditional method of instruction, which involves learning the related definitions and equations, using equations to solve heat transfer…

Flash-Fire Propensity and Heat-Release Rate Studies of Improved Fire Resistant Materials

NASA Technical Reports Server (NTRS)

Fewell, L. L.

1978-01-01

Twenty-six improved fire resistant materials were tested for flash-fire propensity and heat release rate properties. The tests were conducted to obtain a descriptive index based on the production of ignitable gases during the thermal degradation process and on the response of the materials under a specific heat load.

Heat-physical properties of lunar surface material returned to earth by the Luna 16 automatic station

NASA Technical Reports Server (NTRS)

Avduyevskiy, V. S.; Anfimov, N. A.; Marov, M. Y.; Treskin, Y. A.; Shalayev, S. P.; Ekonomov, A. P.

1974-01-01

Density, specific heat capacity, and coefficient of thermal conductivity were studied on a sample of lunar surface material returned by the Luna 16 automatic station. The study was carried out in a helium-filled chamber. The density of the surface material when freely heaped was 1.2 g/cu cm, and when shaken down -- 1.7 g/cu cm. The specific heat capacity was 0.177 + or - 0.010 cal x g/1 x deg/1. The coefficient of thermal conductivity in the material was 4.8 x 10/6 + or - 1.2 x 10/6 cal x cm/1 x sec/1 x deg/1.

Nonlinear Convective Flows in a Laterally Heated Two-Layer System with a Temperature-Dependent Heat Release/Consumption at the Interface

NASA Astrophysics Data System (ADS)

Simanovskii, Ilya; Viviani, Antonio; Dubois, Frank; Queeckers, Patrick

2018-01-01

Nonlinear convective flows developed under the joint action of buoyant and thermocapillary effects in a laterally heated two-layer system filling the closed cavity, have been investigated. The influence of a temperature-dependent interfacial heat release/consumption on nonlinear steady and oscillatory regimes, has been studied. It is shown that sufficiently strong temperature dependence of interfacial heat sinks and heat sources can change the sequence of bifurcations and lead to the development of specific oscillatory regimes in the system.

Climate and heat-related emergencies in Chicago, Illinois (2003-2006).

PubMed

Hartz, Donna A; Golden, Jay S; Sister, Chona; Chuang, Wen-Ching; Brazel, Anthony J

2012-01-01

Extreme heat events are responsible for more deaths in the United States than floods, hurricanes and tornados combined. Yet, highly publicized events, such as the 2003 heat wave in Europe which caused in excess of 35,000 deaths, and the Chicago heat wave of 1995 that produced over 500 deaths, draw attention away from the countless thousands who, each year, fall victim to nonfatal health emergencies and illnesses directly attributed to heat. The health impact of heat waves and excessive heat are well known. Cities worldwide are seeking to better understand heat-related illnesses with respect to the specifics of climate, social demographics and spatial distributions. This information can support better preparation for heat-related emergency situations with regards to planning for response capacity and placement of emergency resources and personnel. This study deals specifically with the relationship between climate and heat-related dispatches (HRD, emergency 911 calls) in Chicago, Illinois, between 2003 and 2006. It is part of a larger, more in-depth, study that includes urban morphology and social factors that impact heat-related emergency dispatch calls in Chicago. The highest occurrences of HRD are located in the central business district, but are generally scattered across the city. Though temperature can be a very good predictor of high HRD, heat index is a better indicator. We determined temperature and heat index thresholds for high HRD. We were also able to identify a lag in HRD as well as other situations that triggered higher (or lower) HRD than would typically be generated for the temperature and humidity levels, such as early afternoon rainfall and special events.

Climate and heat-related emergencies in Chicago, Illinois (2003-2006)

NASA Astrophysics Data System (ADS)

Hartz, Donna A.; Golden, Jay S.; Sister, Chona; Chuang, Wen-Ching; Brazel, Anthony J.

2012-01-01

Extreme heat events are responsible for more deaths in the United States than floods, hurricanes and tornados combined. Yet, highly publicized events, such as the 2003 heat wave in Europe which caused in excess of 35,000 deaths, and the Chicago heat wave of 1995 that produced over 500 deaths, draw attention away from the countless thousands who, each year, fall victim to nonfatal health emergencies and illnesses directly attributed to heat. The health impact of heat waves and excessive heat are well known. Cities worldwide are seeking to better understand heat-related illnesses with respect to the specifics of climate, social demographics and spatial distributions. This information can support better preparation for heat-related emergency situations with regards to planning for response capacity and placement of emergency resources and personnel. This study deals specifically with the relationship between climate and heat-related dispatches (HRD, emergency 911 calls) in Chicago, Illinois, between 2003 and 2006. It is part of a larger, more in-depth, study that includes urban morphology and social factors that impact heat-related emergency dispatch calls in Chicago. The highest occurrences of HRD are located in the central business district, but are generally scattered across the city. Though temperature can be a very good predictor of high HRD, heat index is a better indicator. We determined temperature and heat index thresholds for high HRD. We were also able to identify a lag in HRD as well as other situations that triggered higher (or lower) HRD than would typically be generated for the temperature and humidity levels, such as early afternoon rainfall and special events.

Targeted gene expression without a tissue-specific promoter: creating mosaic embryos using laser-induced single-cell heat shock

NASA Technical Reports Server (NTRS)

Halfon, M. S.; Kose, H.; Chiba, A.; Keshishian, H.

1997-01-01

We have developed a method to target gene expression in the Drosophila embryo to a specific cell without having a promoter that directs expression in that particular cell. Using a digitally enhanced imaging system to identify single cells within the living embryo, we apply a heat shock to each cell individually by using a laser microbeam. A 1- to 2-min laser treatment is sufficient to induce a heat-shock response but is not lethal to the heat-shocked cells. Induction of heat shock was measured in a variety of cell types, including neurons and somatic muscles, by the expression of beta-galactosidase from an hsp26-lacZ reporter construct or by expression of a UAS target gene after induction of hsGAL4. We discuss the applicability of this technique to ectopic gene expression studies, lineage tracing, gene inactivation studies, and studies of cells in vitro. Laser heat shock is a versatile technique that can be adapted for use in a variety of research organisms and is useful for any studies in which it is desirable to express a given gene in only a distinct cell or clone of cells, either transiently or constitutively, at a time point of choice.

Heat capacity reveals the physics of a frustrated spin tube.

PubMed

Ivanov, Nedko B; Schnack, Jürgen; Schnalle, Roman; Richter, Johannes; Kögerler, Paul; Newton, Graham N; Cronin, Leroy; Oshima, Yugo; Nojiri, Hiroyuki

2010-07-16

We report on theoretical and experimental results concerning the low-temperature specific heat of the frustrated spin-tube material [(CuCl(2)tachH(3)Cl]Cl(2) (tach denotes 1,3,5-triaminocyclohexane). This substance turns out to be an unusually perfect spin-tube system which allows to study the physics of quasi-one-dimensional antiferromagnetic structures in rather general terms. An analysis of the specific-heat data demonstrates that at low enough temperatures the system exhibits a Tomonaga-Luttinger liquid behavior corresponding to an effective spin-3/2 antiferromagnetic Heisenberg chain with short-range exchange interactions. On the other hand, around 2 K the composite spin structure of the chain is revealed through a Schottky-type peak in the specific heat. We argue that the dominating contribution to the peak originates from gapped magnon-type excitations related to the internal degrees of freedom of the rung spins.

Heat Capacity Reveals the Physics of a Frustrated Spin Tube

NASA Astrophysics Data System (ADS)

Ivanov, Nedko B.; Schnack, Jürgen; Schnalle, Roman; Richter, Johannes; Kögerler, Paul; Newton, Graham N.; Cronin, Leroy; Oshima, Yugo; Nojiri, Hiroyuki

2010-07-01

We report on theoretical and experimental results concerning the low-temperature specific heat of the frustrated spin-tube material [(CuCl2tachH)3Cl]Cl2 (tach denotes 1,3,5-triaminocyclohexane). This substance turns out to be an unusually perfect spin-tube system which allows to study the physics of quasi-one-dimensional antiferromagnetic structures in rather general terms. An analysis of the specific-heat data demonstrates that at low enough temperatures the system exhibits a Tomonaga-Luttinger liquid behavior corresponding to an effective spin-3/2 antiferromagnetic Heisenberg chain with short-range exchange interactions. On the other hand, around 2 K the composite spin structure of the chain is revealed through a Schottky-type peak in the specific heat. We argue that the dominating contribution to the peak originates from gapped magnon-type excitations related to the internal degrees of freedom of the rung spins.

Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis.

PubMed

Krawczyk, Antonina O; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H J; Kuipers, Oscar P; Eijlander, Robyn T

2017-04-01

Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA 2mob operon carried on the Tn 1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA 2mob required higher HA temperatures for efficient germination than spores lacking spoVA 2mob The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K + (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers. IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases spore responsiveness to nutrient germination triggers, among 17 strains of B. subtilis , including 9 isolates from spoiled food products. Spores of industrial foodborne isolates exhibited, on average, less efficient and slower germination responses and required more severe heat activation than spores from other sources. High heat activation requirements and inefficient, slow germination correlated with elevated resistance of spores to heat and with specific genetic features, indicating a common genetic basis of these three phenotypic traits. Clearly, interstrain variation and numerous factors that shape spore germination behavior challenge standardization of methods to recover highly heat-resistant spores from the environment and have an impact on the efficacy of preservation techniques used by the food industry to control spores. Copyright © 2017 American Society for Microbiology.

Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis

PubMed Central

Krawczyk, Antonina O.; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H. J.; Eijlander, Robyn T.

2017-01-01

ABSTRACT Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA2mob operon carried on the Tn1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA2mob required higher HA temperatures for efficient germination than spores lacking spoVA2mob. The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K+ (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers. IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases spore responsiveness to nutrient germination triggers, among 17 strains of B. subtilis, including 9 isolates from spoiled food products. Spores of industrial foodborne isolates exhibited, on average, less efficient and slower germination responses and required more severe heat activation than spores from other sources. High heat activation requirements and inefficient, slow germination correlated with elevated resistance of spores to heat and with specific genetic features, indicating a common genetic basis of these three phenotypic traits. Clearly, interstrain variation and numerous factors that shape spore germination behavior challenge standardization of methods to recover highly heat-resistant spores from the environment and have an impact on the efficacy of preservation techniques used by the food industry to control spores. PMID:28130296

Signatures of criticality arise from random subsampling in simple population models.

PubMed

Nonnenmacher, Marcel; Behrens, Christian; Berens, Philipp; Bethge, Matthias; Macke, Jakob H

2017-10-01

The rise of large-scale recordings of neuronal activity has fueled the hope to gain new insights into the collective activity of neural ensembles. How can one link the statistics of neural population activity to underlying principles and theories? One attempt to interpret such data builds upon analogies to the behaviour of collective systems in statistical physics. Divergence of the specific heat-a measure of population statistics derived from thermodynamics-has been used to suggest that neural populations are optimized to operate at a "critical point". However, these findings have been challenged by theoretical studies which have shown that common inputs can lead to diverging specific heat. Here, we connect "signatures of criticality", and in particular the divergence of specific heat, back to statistics of neural population activity commonly studied in neural coding: firing rates and pairwise correlations. We show that the specific heat diverges whenever the average correlation strength does not depend on population size. This is necessarily true when data with correlations is randomly subsampled during the analysis process, irrespective of the detailed structure or origin of correlations. We also show how the characteristic shape of specific heat capacity curves depends on firing rates and correlations, using both analytically tractable models and numerical simulations of a canonical feed-forward population model. To analyze these simulations, we develop efficient methods for characterizing large-scale neural population activity with maximum entropy models. We find that, consistent with experimental findings, increases in firing rates and correlation directly lead to more pronounced signatures. Thus, previous reports of thermodynamical criticality in neural populations based on the analysis of specific heat can be explained by average firing rates and correlations, and are not indicative of an optimized coding strategy. We conclude that a reliable interpretation of statistical tests for theories of neural coding is possible only in reference to relevant ground-truth models.

Homoeolog-specific activation of genes for heat acclimation in the allopolyploid grass Brachypodium hybridum.

PubMed

Takahagi, Kotaro; Inoue, Komaki; Shimizu, Minami; Uehara-Yamaguchi, Yukiko; Onda, Yoshihiko; Mochida, Keiichi

2018-04-01

Allopolyploid plants often show wider environmental tolerances than their ancestors; this is expected to be due to the merger of multiple distinct genomes with a fixed heterozygosity. The complex homoeologous gene expression could have been evolutionarily advantageous for the adaptation of allopolyploid plants. Despite multiple previous studies reporting homoeolog-specific gene expression in allopolyploid species, there are no clear examples of homoeolog-specific function in acclimation to a long-term stress condition. We found that the allopolyploid grass Brachypodium hybridum and its ancestor Brachypodium stacei show long-term heat stress tolerance, unlike its other ancestor, Brachypodium distachyon. To understand the physiological traits of B. hybridum, we compared the transcriptome of the 3 Brachypodium species grown under normal and heat stress conditions. We found that the expression patterns of approximately 26% and approximately 38% of the homoeolog groups in B. hybridum changed toward nonadditive expression and nonancestral expression, respectively, under normal condition. Moreover, we found that B. distachyon showed similar expression patterns between normal and heat stress conditions, whereas B. hybridum and B. stacei significantly altered their transcriptome in response to heat after 3 days of stress exposure, and homoeologs that were inherited from B. stacei may have contributed to the transcriptional stress response to heat in B. hybridum. After 15 days of heat exposure, B. hybridum and B. stacei maintained transcriptional states similar to those under normal conditions. These results suggest that an earlier response to heat that was specific to homoeologs originating from B. stacei contributed to cellular homeostasis under long-term heat stress in B. hybridum. Our results provide insights into different regulatory events of the homoeo-transcriptome that are associated with stress acclimation in allopolyploid plants.

Boechera Species Exhibit Species-Specific Responses to Combined Heat and High Light Stress

PubMed Central

Gallas, Genna; Waters, Elizabeth R.

2015-01-01

As sessile organisms, plants must be able to complete their life cycle in place and therefore tolerance to abiotic stress has had a major role in shaping biogeographical patterns. However, much of what we know about plant tolerance to abiotic stresses is based on studies of just a few plant species, most notably the model species Arabidopsis thaliana. In this study we examine natural variation in the stress responses of five diverse Boechera (Brassicaceae) species. Boechera plants were exposed to basal and acquired combined heat and high light stress. Plant response to these stresses was evaluated based on chlorophyll fluorescence measurements, induction of leaf chlorosis, and gene expression. Many of the Boechera species were more tolerant to heat and high light stress than A. thaliana. Gene expression data indicates that two important marker genes for stress responses: APX2 (Ascorbate peroxidase 2) and HsfA2 (Heat shock transcription factor A2) have distinct species-specific expression patterns. The findings of species-specific responses and tolerance to stress indicate that stress pathways are evolutionarily labile even among closely related species. PMID:26030823

Effect of water content on specific heat capacity of porcine septum cartilage

NASA Astrophysics Data System (ADS)

Chae, Yongseok; Lavernia, Enrique J.; Wong, Brian J.

2002-06-01

The effect of water content on specific heat capacity was examined using temperature modulated Differential Scanning Calorimetry (TMDSC). This research was motivated in part by the development laser cartilage reshaping operations, which use photothermal heating to accelerate stress relaxation and shape change. Deposition of thermal energy leads to mechanical stress relaxation and redistribution of cartilage internal stresses, which may lead to a permanent shape change. The specific heat of cartilage specimens (dia: 3 mm and thickness 1-2 mm) was measured using a heating rate of 2 degree(s)C/min for conventional DSC and 2 degree(s)C/min with an amplitude 0.38-0.45 degree(s)C and a period 60-100 sec for TMDSC. The amount of water in cartilaginous tissue was determined using thermogravimetry analysis (TGA) under ambient conditions. In order to correlate changes in heat flow with alterations in cartilage mechanical behavior, dynamic mechanical temperature analysis (DMTA) was used to estimate the specific transition temperatures where stress relaxation occurs. With decreasing water content, we identified a phase transition that shifted to a higher temperature after 35-45% water content was measured. The phase transition energy increased from 0.12 J/g to 1.68 J/g after a 45% weight loss. This study is a preliminary investigation focused on understanding the mechanism of the stress relaxation of cartilage during heating. The energy requirement of such a transition estimated using TMDSC and temperature range, where cartilage shape changes likely occur, was estimated.

Heat capacity and transport measurements in sputtered niobium-zirconium multilayers

NASA Astrophysics Data System (ADS)

Broussard, P. R.; Mael, D.

1989-08-01

We have studied the electrical resistivity and heat capacity for multilayers of niobium and zirconium prepared by magnetron sputtering for values of the bilayer period Λ varying from 4 to 950 Å. We find a transition in the thermal part of the resistivity that correlates with the coherent-to-incoherent transition seen in earlier work. The heat capacity data for the normal state show anomalous behavior for both the electronic coefficient γ and the Debye temperature. We also study the variation in Tc and the jump in the specific heat.

Heat exchangers in regenerative gas turbine cycles

NASA Astrophysics Data System (ADS)

Nina, M. N. R.; Aguas, M. P. N.

1985-09-01

Advances in compact heat exchanger design and fabrication together with fuel cost rises continuously improve the attractability of regenerative gas turbine helicopter engines. In this study cycle parameters aiming at reduced specific fuel consumption and increased payload or mission range, have been optimized together with heat exchanger type and size. The discussion is based on a typical mission for an attack helicopter in the 900 kw power class. A range of heat exchangers is studied to define the most favorable geometry in terms of lower fuel consumption and minimum engine plus fuel weight. Heat exchanger volume, frontal area ratio and pressure drop effect on cycle efficiency are considered.

Experimental Investigation on the Specific Heat of Carbonized Phenolic Resin-Based Ablative Materials

NASA Astrophysics Data System (ADS)

Zhao, Te; Ye, Hong; Zhang, Lisong; Cai, Qilin

2017-10-01

As typical phenolic resin-based ablative materials, the high silica/phenolic and carbon/phenolic composites are widely used in aerospace field. The specific heat of the carbonized ablators after ablation is an important thermophysical parameter in the process of heat transfer, but it is rarely reported. In this investigation, the carbonized samples of the high silica/phenolic and carbon/phenolic were obtained through carbonization experiments, and the specific heat of the carbonized samples was determined by a 3D DSC from 150 °C to 970 °C. Structural and compositional characterizations were performed to determine the mass fractions of the fiber and the carbonized product of phenolic which are the two constituents of the carbonized samples, while the specific heat of each constituent was also measured by 3D DSC. The masses of the carbonized samples were reduced when heated to a high temperature in the specific heat measurements, due to the thermal degradation of the carbonized product of phenolic resin in the carbonized samples. The raw experimental specific heat of the two carbonized samples and the carbonized product of phenolic resin was modified according to the quality changes of the carbonized samples presented by TGA results. Based on the mass fraction and the specific heat of each constituent, a weighted average method was adopted to obtain the calculated results of the carbonized samples. Due to the unconsolidated property of the fiber samples which impacts the reliability of the DSC measurement, there is a certain deviation between the experimental and calculated results of the carbonized samples. Considering the similarity of composition and structure, the data of quartz glass and graphite were used to substitute the specific heat of the high silica fiber and carbon fiber, respectively, resulting in better agreements with the experimental ones. Furthermore, the accurate specific heat of the high silica fiber and carbon fiber bundles was obtained by inversion, enabling the prediction of the specific heat of the carbonized ablators with different constituent mass fractions by means of the weighted average method in engineering.

Students’ mental model on heat convection concept and its relation with students conception on heat and temperature

NASA Astrophysics Data System (ADS)

Amalia, R.; Sari, I. M.; Sinaga, P.

2017-02-01

This research depended by previous studies that only to find out the misconceptions of students without figuring out the mechanism of the misconceptions. The mechanism of misconceptions can be studied more deeply with mental models. The purpose of this study was to find students ‘mental models of heat convection and its relation with students conception on heat and temperature. The method used in this study is exploratory mixed method design that implemented in one of the high schools in Bandung. The results showed that 7 mental models of heat convection in Chiou’s study (2013), only first model (diffusion-based convention), third model (evenly distributed convection) and fifth model (warmness topped convection II) were found and model hybrid convection as a new mental model. In addition, no specific relationship between mental models and categories of students’ conceptions on heat and temperature.

Al/ oil nanofluids inside annular tube: an experimental study on convective heat transfer and pressure drop

NASA Astrophysics Data System (ADS)

Jafarimoghaddam, Amin; Aberoumand, Sadegh; Javaherdeh, Kourosh; Arani, Ali Akbar Abbasian; Jafarimoghaddam, Reza

2018-04-01

In this work, an experimental study on nanofluid preparation stability, thermo-physical properties, heat transfer performance and friction factor of Al/ Oil nanofluids has been carried out. Electrical Explosion Wire ( E.E.W) which is one of the most reliable one-step techniques for nanofluids preparation has been used. An annular tube has been considered as the test section in which the outer tube was subject to a uniform heat flux boundary condition of about 204 W. The utilized nanofluids were prepared in three different volume concentrations of 0.011%, 0.044% and 0.171%. A wide range of parameters such as Reynolds number Prandtl number, viscosity, thermal conductivity, density, specific heat, convective heat transfer coefficient, Nusselt number and the friction factor have been studied. The experiment was conducted in relatively low Reynolds numbers of less than 160 and within a hydrodynamically fully-developed regime. According to the results, thermal conductivity, density and viscosity increased depending on the volume concentrations and working temperatures while the specific heat declined. More importantly, it was observed that convective heat transfer coefficient and Nusselt number enhanced by 28.6% and 16.4%, respectively, for the highest volume concentration. Finally, the friction factor (which plays an important role in the pumping power) was found to be increased around 18% in the volume fraction of 0.171%.

Heat Wave and Mortality: A Multicountry, Multicommunity Study

PubMed Central

Gasparrini, Antonio; Armstrong, Ben G.; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; Coelho, Micheline de Sousa Zanotti Stagliorio; Pan, Xiaochuan; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue-Liang Leon; Wu, Chang-Fu; Zanobetti, Antonella; Schwartz, Joel D.; Bell, Michelle L.; Scortichini, Matteo; Michelozzi, Paola; Punnasiri, Kornwipa; Li, Shanshan; Tian, Linwei; Garcia, Samuel David Osorio; Seposo, Xerxes; Overcenco, Ala; Zeka, Ariana; Goodman, Patrick; Dang, Tran Ngoc; Dung, Do Van; Mayvaneh, Fatemeh; Saldiva, Paulo Hilario Nascimento; Williams, Gail; Tong, Shilu

2017-01-01

Background: Few studies have examined variation in the associations between heat waves and mortality in an international context. Objectives: We aimed to systematically examine the impacts of heat waves on mortality with lag effects internationally. Methods: We collected daily data of temperature and mortality from 400 communities in 18 countries/regions and defined 12 types of heat waves by combining community-specific daily mean temperature ≥90th, 92.5th, 95th, and 97.5th percentiles of temperature with duration ≥2, 3, and 4 d. We used time-series analyses to estimate the community-specific heat wave–mortality relation over lags of 0–10 d. Then, we applied meta-analysis to pool heat wave effects at the country level for cumulative and lag effects for each type of heat wave definition. Results: Heat waves of all definitions had significant cumulative associations with mortality in all countries, but varied by community. The higher the temperature threshold used to define heat waves, the higher heat wave associations on mortality. However, heat wave duration did not modify the impacts. The association between heat waves and mortality appeared acutely and lasted for 3 and 4 d. Heat waves had higher associations with mortality in moderate cold and moderate hot areas than cold and hot areas. There were no added effects of heat waves on mortality in all countries/regions, except for Brazil, Moldova, and Taiwan. Heat waves defined by daily mean and maximum temperatures produced similar heat wave–mortality associations, but not daily minimum temperature. Conclusions: Results indicate that high temperatures create a substantial health burden, and effects of high temperatures over consecutive days are similar to what would be experienced if high temperature days occurred independently. People living in moderate cold and moderate hot areas are more sensitive to heat waves than those living in cold and hot areas. Daily mean and maximum temperatures had similar ability to define heat waves rather than minimum temperature. https://doi.org/10.1289/EHP1026 PMID:28886602

Occupational heat strain in a hot underground metal mine.

PubMed

Lutz, Eric A; Reed, Rustin J; Turner, Dylan; Littau, Sally R

2014-04-01

In a hot underground metal mine, this study evaluated the relationship between job task, physical body type, work shift, and heat strain. Thirty-one miners were evaluated during 98 shifts while performing deep shaft-sinking tasks. Continuous core body temperature, heart rate, pre- and postshift urine specific gravity (USG), and body mass index were measured. Cutting and welding tasks were associated with significantly (P < 0.05) increased core body temperature, maximum heart rate, and increased postshift urine specific gravity. Miners in the obese level II and III body mass index categories, as well as those working night shift, had lower core body temperatures (P < 0.05). This study confirms that job task, body type, and shift are risk factors for heat strain.

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

Analysis for Heat Transfer in a High Current-Passing Carbon Nanosphere Using Nontraditional Thermal Transport Model.

PubMed

Hol C Y; Chen, B C; Tsai, Y H; Ma, C; Wen, M Y

2015-11-01

This paper investigates the thermal transport in hollow microscale and nanoscale spheres subject to electrical heat source using nontraditional thermal transport model. Working as supercapacitor electrodes, carbon hollow micrometer- and nanometer-sized spheres needs excellent heat transfer characteristics to maintain high specific capacitance, long cycle life, and high power density. In the nanoscale regime, the prediction of heat transfer from the traditional heat conduction equation based on Fourier's law deviates from the measured data. Consequently, the electrical heat source-induced heat transfer characteristics in hollow micrometer- and nanometer-sized spheres are studied using nontraditional thermal transport model. The effects of parameters on heat transfer in the hollow micrometer- and nanometer-sized spheres are discussed in this study. The results reveal that the heat transferred into the spherical interior, temperature and heat flux in the hollow sphere decrease with the increasing Knudsen number when the radius of sphere is comparable to the mean free path of heat carriers.

Heat acclimation: Gold mines and genes

PubMed Central

Schneider, Suzanne M.

2016-01-01

ABSTRACT The underground gold mines of South Africa offer a unique historical setting to study heat acclimation. The early heat stress research was conducted and described by a young medical officer, Dr. Aldo Dreosti. He developed practical and specific protocols to first assess the heat tolerance of thousands of new mining recruits, and then used the screening results as the basis for assigning a heat acclimation protocol. The mines provide an interesting paradigm where the prevention of heat stroke evolved from genetic selection, where only Black natives were recruited due to a false assumption of their intrinsic tolerance to heat, to our current appreciation of the epigenetic and other molecular adaptations that occur with exposure to heat. PMID:28090556

Analysis of Adsorbate-Adsorbate and Adsorbate-Adsorbent Interactions to Decode Isosteric Heats of Gas Adsorption.

PubMed

Madani, S Hadi; Sedghi, Saeid; Biggs, Mark J; Pendleton, Phillip

2015-12-21

A qualitative interpretation is proposed to interpret isosteric heats of adsorption by considering contributions from three general classes of interaction energy: fluid-fluid heat, fluid-solid heat, and fluid-high-energy site (HES) heat. Multiple temperature adsorption isotherms are defined for nitrogen, T=(75, 77, 79) K, argon at T=(85, 87, 89) K, and for water and methanol at T=(278, 288, 298) K on a well-characterized polymer-based, activated carbon. Nitrogen and argon are subjected to isosteric heat analyses; their zero filling isosteric heats of adsorption are consistent with slit-pore, adsorption energy enhancement modelling. Water adsorbs entirely via specific interactions, offering decreasing isosteric heat at low pore filling followed by a constant heat slightly in excess of water condensation enthalpy, demonstrating the effects of micropores. Methanol offers both specific adsorption via the alcohol group and non-specific interactions via its methyl group; the isosteric heat increases at low pore filling, indicating the predominance of non-specific interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental determination of nanofluid specific heat with SiO2 nanoparticles in different base fluids

NASA Astrophysics Data System (ADS)

Akilu, S.; Baheta, A. T.; Sharma, K. V.; Said, M. A.

2017-09-01

Nanostructured ceramic materials have recently attracted attention as promising heat transfer fluid additives owing to their outstanding heat storage capacities. In this paper, experimental measurements of the specific heats of SiO2-Glycerol, SiO2-Ethylene Glycol, and SiO2-Glycerol/Ethylene Glycol mixture 60:40 ratio (by mass) nanofluids with different volume concentrations of 1.0-4.0% have been carried out using differential scanning calorimeter at temperatures of 25 °C and 50 °C. Experimental results indicate lower specific heat capacities are found with SiO2 nanofluids compared to their respective base fluids. The specific heat was decreasing with the increase of concentration, and this decrement depends on upon the type of the base fluid. It is observed that temperature has a positive impact on the specific heat capacity. Furthermore, the experimental values were compared with the theoretical model predictions, and a satisfactory agreement was established.

Forced and natural convection in aggregate-laden nanofluids

NASA Astrophysics Data System (ADS)

Thajudeen, Thaseem; Hogan, Christopher J.

2011-12-01

A number of experimental and theoretical studies of convective heat transfer in nanofluids (liquid suspensions of nanoparticles, typically with features below 100 nm in size) reveal contrasting results; nanoparticles can either enhance or reduce the convective heat transfer coefficient. These disparate conclusions regarding the influence of nanoparticles on convective heat transfer may arise due to the aggregation of nanoparticles, which is often not considered in studies of nanofluids. Here, we examine theoretically forced and natural convective heat transfer of aggregate-laden nanofluids using Monte Carlo-based models to determine how the aggregate morphology influences the convective heat transfer coefficient. Specifically, in this study, it is first shown that standard heat transfer correlations should apply to nanofluids, and the main influence of the nanoparticles is to alter suspension thermal conductivity, dynamic viscosity, density, specific heat, and thermal expansion coefficient. Aggregated particles in suspension are modeled as quasi-fractal aggregates composed of individual primary particles described by the primary particle radius, number of primary particles, fractal (Hausdorff) dimension, pre-exponential factor, and degree of coalescence between primary particles. A sequential algorithm is used to computationally generate aggregates with prescribed morphological descriptors. Four types of aggregates are considered; spanning the range of aggregate morphologies observed in nanofluids. For each morphological type, the influences of aggregates on nanofluid dynamic viscosity and thermal conductivity are determined via first passage-based Brownian dynamics calculations. It is found that depending on both the material properties of the nanoparticles as well as the nanoparticle morphology, the addition of nanoparticles to a suspension can either increase or decrease both the forced and natural convective heat transfer coefficients, with both a 51% increase and a 32% decrease in the heat transfer coefficient achievable at particle volume fractions of 0.05. This study shows clearly that the influence of particle morphology needs to be accounted for in all studies of heat transfer in nanofluids.

Third law of thermodynamics in the presence of a heat flux

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

Camacho, J.

1995-01-01

Following a maximum entropy formalism, we study a one-dimensional crystal under a heat flux. We obtain the phonon distribution function and evaluate the nonequilibrium temperature, the specific heat, and the entropy as functions of the internal energy and the heat flux, in both the quantum and the classical limits. Some analogies between the behavior of equilibrium systems at low absolute temperature and nonequilibrium steady states under high values of the heat flux are shown, which point to a possible generalization of the third law in nonequilibrium situations.

Global climate change: impact of heat waves under different definitions on daily mortality in Wuhan, China.

PubMed

Zhang, Yunquan; Feng, Renjie; Wu, Ran; Zhong, Peirong; Tan, Xiaodong; Wu, Kai; Ma, Lu

2017-01-01

There was no consistent definition for heat wave worldwide, while a limited number of studies have compared the mortality effect of heat wave as defined differently. This paper aimed to provide epidemiological evidence for policy makers to determine the most appropriate definition for local heat wave warning systems. We developed 45 heat wave definitions (HWs) combining temperature indicators and temperature thresholds with durations. We then assessed the impact of heat waves under various definitions on non-accidental mortality in hot season (May-September) in Wuhan, China during 2003-2010. Heat waves defined by HW14 (daily mean temperature ≥ 99.0th percentile and duration ≥ 3 days) had the best predictive ability in assessing the mortality effects of heat wave with the relative risk of 1.63 (95% CI : 1.43, 1.89) for total mortality. The group-specific mortality risk using official heat wave definition of Chinese Meteorological Administration was much smaller than that using HW14. We also found that women, and the elderly (age ≥ 65) were more susceptible to heat wave effects which were stronger and longer lasting. These findings suggest that region specific heat wave definitions are crucial and necessary for developing efficient local heat warning systems and for providing evidence for policy makers to protect the vulnerable population.

Effect of surface hydroxyl groups on heat capacity of mesoporous silica

NASA Astrophysics Data System (ADS)

Marszewski, Michal; Butts, Danielle; Lan, Esther; Yan, Yan; King, Sophia C.; McNeil, Patricia E.; Galy, Tiphaine; Dunn, Bruce; Tolbert, Sarah H.; Hu, Yongjie; Pilon, Laurent

2018-05-01

This paper quantifies the effect of surface hydroxyl groups on the effective specific and volumetric heat capacities of mesoporous silica. To achieve a wide range of structural diversity, mesoporous silica samples were synthesized by various methods, including (i) polymer-templated nanoparticle-based powders, (ii) polymer-templated sol-gel powders, and (iii) ambigel silica samples dried by solvent exchange at room temperature. Their effective specific heat capacity, specific surface area, and porosity were measured using differential scanning calorimetry and low-temperature nitrogen adsorption-desorption measurements. The experimentally measured specific heat capacity was larger than the conventional weight-fraction-weighted specific heat capacity of the air and silica constituents. The difference was attributed to the presence of OH groups in the large internal surface area. A thermodynamic model was developed based on surface energy considerations to account for the effect of surface OH groups on the specific and volumetric heat capacity. The model predictions fell within the experimental uncertainty.

Thermodynamic properties Ar films on the surface of a bundle of carbon nanotubes

NASA Astrophysics Data System (ADS)

Cole, Milton; Gatica, Silvina

2005-03-01

We employ canonical Monte Carlo simulations to explore the properties of an Argon film adsorbed on the external surface of a bundle of carbon nanotubes. The study is concerned primarily with three properties: specific heat, differential heat of adsorption, and Ar-Ar correlation functions. These measurable functions exhibit information about the dependence of film structure on coverage and temperature. Our results are intended to stimulate further experimental studies of this system and analogous systems involving other gases on nanotube bundles. One of the more interesting general results is that the specific heat is typically larger than might have been expected. Particularly remarkable outcome from the correlation function studies include the reduced longitudinal correlations in the groove and striped phases as T rises above 60 K. These results would be amenable to testing by diffraction experiments.

Non-specific protein modifications by a phytochemical induce heat shock response for self-defense.

PubMed

Ohnishi, Kohta; Ohkura, Shinya; Nakahata, Erina; Ishisaka, Akari; Kawai, Yoshichika; Terao, Junji; Mori, Taiki; Ishii, Takeshi; Nakayama, Tsutomu; Kioka, Noriyuki; Matsumoto, Shinya; Ikeda, Yasutaka; Akiyama, Minoru; Irie, Kazuhiro; Murakami, Akira

2013-01-01

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.

Non-Specific Protein Modifications by a Phytochemical Induce Heat Shock Response for Self-Defense

PubMed Central

Ohnishi, Kohta; Ohkura, Shinya; Nakahata, Erina; Ishisaka, Akari; Kawai, Yoshichika; Terao, Junji; Mori, Taiki; Ishii, Takeshi; Nakayama, Tsutomu; Kioka, Noriyuki; Matsumoto, Shinya; Ikeda, Yasutaka; Akiyama, Minoru; Irie, Kazuhiro; Murakami, Akira

2013-01-01

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities. PMID:23536805

A Radio-frequency Coupling Network for Heating of Citrate-coated Gold Nanoparticles for Cancer Therapy: Design and Analysis

PubMed Central

Kruse, Dustin E.; Stephens, Douglas N.; Lindfors, Heather A.; Ingham, Elizabeth S.; Paoli, Eric E.; Ferrara, Katherine W.

2012-01-01

Gold nanoparticles (GNPs) are non-toxic, can be functionalized with ligands, and preferentially accumulate in tumors. We have developed a 13.56 MHz radiofrequency-electromagnetic field (RF-EM) delivery system capable of generating high electric field strengths required for non-invasive, non-contact heating of GNPs. The bulk heating and specific heating rates were measured as a function of NP size and concentration. It was found that heating is both size and concentration dependent, with 5 nm particles producing a 50.6±0.2°C temperature rise in 30 s for 25 μg/mL gold (125 W input). The specific heating rate was also size and concentration dependent, with 5 nm particles producing a specific heating rate of 356±78 kW/g gold at 16 μg/mL (125 W input). Furthermore, we demonstrate that cancer cells incubated with GNPs are killed when exposed to 13.56 MHz RFEM fields. Compared to cells that were not incubated with GNPs, 3 out of 4 RF-treated groups showed a significant enhancement of cell death with GNPs (p<0.05). GNP-enhanced cell killing appears to require temperatures above 50°C for the experimental parameters used in this study. Transmission electron micrographs show extensive vacuolization with the combination of GNPs and RF treatment. PMID:21402506

Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel

NASA Astrophysics Data System (ADS)

Walker, Jacob D.

Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces requires welding in the assembly; this drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment. As with most metallic materials grade 91 steel requires a very specific heat treatment process. This process includes a specific temperature and duration at that temperature to achieve the heat treatment desired. Extensive research has been done to determine the proper temperatures and duration to provide the proper microstructure for the superior mechanical properties that are inherent to Grade 91 steel. The welded sections are typically large structures that require local heat treatments and cannot be placed in an oven. The locations of these structures vary from indoors in a controlled environment to outdoors with unpredictable environments. These environments can be controlled somewhat, however in large part the surrounding conditions are unchangeable. Therefore, there is a need to develop methods to accurately apply the surrounding conditions and geometries to a theoretical model in order to provide the proper requirements for the local heat treatment procedure. Within this requirement is the requirement to define unknowns used in the heat transfer equations so that accurate models can be produced and accurate results predicted. This study investigates experimentally and numerically the heat transfer and temperature fields of Grade 91 piping in a local heat treatment. The objective of this thesis research is to determine all of the needed heat transfer coefficients. The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing a ceramic heat blanket. This will be done through an inverse method by collecting actual data from different conditions and temperatures. Then the heat transfer coefficients are used to set up a model to determine the appropriate post-weld heat treatment conditions for Grade 91 steel. This will enable one to use the derived coefficients to run a forward analysis with the specific geometry and conditions they will encounter in the heat treatment process for their application. The analysis will provide a theoretical determination of time and temperatures needed to maintain the temperature for the proper time needed to properly heat treat the welded section in the desired areas that have been joined together through a welding process. Finally time and temperature combinations are compared with experimentally measured data. The forward model code applied to the parameters of the heat-treatment can then appropriately assist to determine the proper post-weld heat treatment conditions for the desired toughness and creep properties. This research is very beneficial to the joining of metals industry because it provides a way to ensure the method used to heat treat the welded section is being properly done, and the required heat treatment is achieved. It is applicable to many different geometries so that it can be modified to specific situations.

49 CFR 179.100-10 - Postweld heat treatment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-10 Postweld heat... heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars...

49 CFR 179.100-10 - Postweld heat treatment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-10 Postweld heat... heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars...

49 CFR 179.100-10 - Postweld heat treatment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-10 Postweld heat... heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars...

Correlation between structural and thermodynamic properties of some selenium based phase-change materials

NASA Astrophysics Data System (ADS)

Chandel, Namrata; Mehta, Neeraj

2018-04-01

In this study, we prepared novel selenium rich multi-component glasses by incorporating In, Cd and Sb as foreign elements in an Sn containing Sesbnd Te system in order to study their metal-induced effects on the thermal properties of the parent ternary glass. In particular, we determined the thermodynamic parameters of Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glassy semiconductors in a non-isothermal environment using the differential scanning calorimetry. Calorimetric measurements were obtained in the glass transition regions for Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glasses to determine their thermodynamic parameters such as the specific heat, enthalpy, and entropy during glass transition. We analyzed the variation in the specific heat before and after the heat capacity jump in these alloys. The metal-induced effects of foreign elements on the thermodynamic properties of the parent glass were also investigated in terms of the influence of the elemental specific heat of the added elemental metal as well as the thermal stability and glass-forming ability of the glasses.

Thermal analysis of large-capacity LiFePO4 power batteries for electric vehicles

NASA Astrophysics Data System (ADS)

Lin, Chunjing; Xu, Sichuan; Li, Zhao; Li, Bin; Chang, Guofeng; Liu, Jinling

2015-10-01

Excellent design of a thermal management system requires good understanding of the thermal behaviors of power batteries. In this study, the electrochemical and heat performances of a prismatic 40 Ah C/LiFePO4 battery are investigated with a focus on the influence of temperature on cell capacity in a mixed charge-discharge cycle. In addition, the heat generation and energy efficiency of a battery are determined during charge and discharge at different current rates. The experimental results indicate that in certain temperature ranges, both the charging and discharging capacities increase significantly as the temperature increases. In addition, the energy efficiency reaches more than 95% when the battery runs at a current rate of 0.33 C-2 C and temperature of 25-45 °C. A thermal mathematical model based on experimentally obtained internal resistances and entropy coefficients is developed. Using this model, the increase in the battery temperature is simulated based on specific heat values that are measured experimentally and calculated theoretically. The results from the simulation indicate that the temperature increase agrees well with the experimental values, the measured specific heat provides better results than the calculated specific heat and the heat generated decreases as the temperature increases.

Meteoroid Protection Methods for Spacecraft Radiators Using Heat Pipes

NASA Technical Reports Server (NTRS)

Ernst, D. M.

1979-01-01

Various aspects of achieving a low mass heat pipe radiator for the nuclear electric propulsion spacecraft were studied. Specific emphasis was placed on a concept applicable to a closed Brayton cycle power sub-system. Three aspects of inter-related problems were examined: (1) the armor for meteoroid protection, (2) emissivity of the radiator surface, and (3) the heat pipe itself. The study revealed several alternatives for the achievement of the stated goal, but a final recommendation for the best design requires further investigation.

Melting temperature and enthalpy variations of phase change materials (PCMs): a differential scanning calorimetry (DSC) analysis

NASA Astrophysics Data System (ADS)

Sun, Xiaoqin; Lee, Kyoung Ok; Medina, Mario A.; Chu, Youhong; Li, Chuanchang

2018-06-01

Differential scanning calorimetry (DSC) analysis is a standard thermal analysis technique used to determine the phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy of phase change materials (PCMs). To determine the appropriate heating rate and sample mass, various DSC measurements were carried out using two kinds of PCMs, namely N-octadecane paraffin and calcium chloride hexahydrate. The variations in phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy were observed within applicable heating rates and sample masses. It was found that the phase transition temperature range increased with increasing heating rate and sample mass; while the heat of fusion varied without any established pattern. The specific heat decreased with the increase of heating rate and sample mass. For accuracy purpose, it is recommended that for PCMs with high thermal conductivity (e.g. hydrated salt) the focus will be on heating rate rather than sample mass.

Proposed modification to the specification for dry heat microbial reduction of spacecraft hardware for future US missions

NASA Astrophysics Data System (ADS)

James; Spry, A.; Beaudet, Robert; Schubert, Wayne

Dry heat microbial reduction (DHMR) is the primary technique used to reduce the microbial load of spacecraft and component parts to comply with planetary protection requirements. Often, manufacturing processes involve heating flight hardware to high temperatures for purposes other than planetary protection DHMR. At present, the existing specification in NASA document NPR8020.12C, describing the process lethality on B. atrophaeus (ATCC 9372) bacterial spores, does not allow for additional planetary protection bioburden reduction credit for processing outside a narrow temperature, time and humidity window. However, recent studies (Schubert et al., COSPAR 2008) from a comprehensive multi-year laboratory research effort have generated enhanced data sets on four aspects of the current specification: time and temperature combination effects, the effect that humidity has on spore lethality, the lethality for spores with exceptionally high thermal resistance (so called "hardies"), and the extended exposure requirement for encapsulated microorganisms. This paper describes proposed modifications to the specification, based on the data set generated in the referenced study. The proposed modifications are intended to broaden the scope of the current specification while still maintaining a confident conservative interpretation of the lethality of the DHMR process on microorganisms. Potential cost and schedule benefits to future missions utilizing the revised specification will be highlighted.

Energy conservation measures for the Charles E. Shea Senior High School, Pawtucket, Rhode Island. Public service report

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

Not Available

1979-07-01

A thermographic audit of a Pawtucket, Rhode Island high school is reported. Conducted with the aid of an infrared camera system, this thermographic study located heat losses not evident to the naked eye. Heat losses were documented and the thermograms analyzed to obtain complete knowledge of the location of all heat losses from the building complex. Each thermogram showed one or more types of heat loss together with the specific section of the building where it occurred. Priorities were assigned to various retrofit processes and a thermographic inspection conducted after retrofitting to confirm its efficacy. The study comprised an analysismore » and recommendations of heat loss and heating system appraisals plus an analysis of roof moisture inspection. Numerous thermograms illustrate the report.« less

Level of tissue differentiation influences the activation of a heat-inducible flower-specific system for genetic containment in poplar (Populus tremula L.).

PubMed

Hoenicka, Hans; Lehnhardt, Denise; Nunna, Suneetha; Reinhardt, Richard; Jeltsch, Albert; Briones, Valentina; Fladung, Matthias

2016-02-01

Differentiation level but not transgene copy number influenced activation of a gene containment system in poplar. Heat treatments promoted CRE gene body methylation. The flower-specific transgene deletion was confirmed. Gene flow between genetic modified trees and their wild relatives is still motive of concern. Therefore, approaches for gene containment are required. In this study, we designed a novel strategy for achieving an inducible and flower-specific transgene removal from poplar trees but still expressing the transgene in the plant body. Hence, pollen carrying transgenes could be used for breeding purposes under controlled conditions in a first phase, and in the second phase genetic modified poplars developing transgene-free pollen grains could be released. This approach is based on the recombination systems CRE/loxP and FLP/frt. Both gene constructs contained a heat-inducible CRE/loxP-based spacer sequence for in vivo assembling of the flower-specific FLP/frt system. This allowed inducible activation of gene containment. The FLP/frt system was under the regulation of a flower-specific promoter, either CGPDHC or PTD. Our results confirmed complete CRE/loxP-based in vivo assembling of the flower-specific transgene excision system after heat treatment in all cells for up to 30 % of regenerants derived from undifferentiated tissue cultures. Degradation of HSP::CRE/loxP spacer after recombination but also persistence as extrachromosomal DNA circles were detected in sub-lines obtained after heat treatments. Furthermore, heat treatment promoted methylation of the CRE gene body. A lower methylation level was detected at CpG sites in transgenic sub-lines showing complete CRE/loxP recombination and persistence of CRE/loxP spacer, compared to sub-lines with incomplete recombination. However, our results suggest that low methylation might be necessary but not sufficient for recombination. The flower-specific FLP/frt-based transgene deletion was confirmed in 6.3 % of flowers.

Pressure Dependence of the Specific-Heat Jump at the Superfluid Transition and the Effective Mass of 3He

NASA Astrophysics Data System (ADS)

Alvesalo, T. A.; Haavasoja, T.; Manninen, M. T.; Soinne, A. T.

1980-04-01

The specific heat of liquid 3He has been measured from 1 to 10 mK between 0 and 32.5 bars. The values implied for the effective mass are considerably smaller than the currently accepted ones. Near zero pressure the specific-heat jump is close to the BCS value 1.43, and at 32.5 bars it has reached 1.90 in the B phase and 2.04 in the A phase. The temperature dependence of the specific heat in the B phase agrees with a model of Serene and Rainer. The latent heat at the A-B transition has been measured.

Modeling and impacts of the latent heat of phase change and specific heat for phase change materials

NASA Astrophysics Data System (ADS)

Scoggin, J.; Khan, R. S.; Silva, H.; Gokirmak, A.

2018-05-01

We model the latent heats of crystallization and fusion in phase change materials with a unified latent heat of phase change, ensuring energy conservation by coupling the heat of phase change with amorphous and crystalline specific heats. We demonstrate the model with 2-D finite element simulations of Ge2Sb2Te5 and find that the heat of phase change increases local temperature up to 180 K in 300 nm × 300 nm structures during crystallization, significantly impacting grain distributions. We also show in electrothermal simulations of 45 nm confined and 10 nm mushroom cells that the higher amorphous specific heat predicted by this model increases nucleation probability at the end of reset operations. These nuclei can decrease set time, leading to variability, as demonstrated for the mushroom cell.

Laboratory Activity: Specific Heat by Change in Internal Energy of Silly Putty

NASA Astrophysics Data System (ADS)

Koser, John

2011-12-01

Students in introductory physics courses often don't study thermodynamics or thermodynamic events. If any thermal physics is taught in introductory courses (e.g., Physics 101 for Liberal Arts Majors), it usually involves the concepts of specific heat and various temperature scales. Seldom are the first and second laws of thermodynamics taught in detail. In this article, we look at a means to obtain real-time data that will lead to clarifying the first law.

Specific heat of the chiral-soliton-lattice phase in Yb(Ni0.94Cu0.06)3Al9

NASA Astrophysics Data System (ADS)

Ninomiya, Hiroki; Sato, Takaaki; Inoue, Katsuya; Ohara, Shigeo

2018-05-01

We have studied the monoaxial-chiral helimagnet YbNi3Al9 and its-substituted analogue Yb(Ni0.94Cu0.06)3Al9. These compounds belong to a chiral space group R32. In Yb(Ni0.94Cu0.06)3Al9 with the magnetic ordering temperature TM = 6.4 K , only when the magnetic field is applied perpendicular to the helical axis, the chiral soliton lattice is observed below Hc = 10 kOe . YbNi3Al9 with TM = 3.4 K exhibits a metamagnetic transition at Hc = 1 kOe in 2 K. To study the formation of chiral helimagnetic state and chiral soliton lattice, we have measured the specific heat in magnetic fields applied parallel and perpendicular to the helical axis. In zero field, with decreasing temperature, specific heat shows λ-type phase transition from paramagnetic state to chiral helimagnetic one. At the temperature where the chiral soliton lattice emerges, we have found that the specific heat shows a sharp peak. In addition, at around the crossover between paramagnetic state and forced-ferromagnetic one, a broad maximum has been observed. We have determined the magnetic phase diagrams of YbNi3Al9 and Yb(Ni0.94Cu0.06)3Al9.

Effect of the conditions of sintering of sodium-reduced tantalum powders on their characteristics

NASA Astrophysics Data System (ADS)

Prokhorova, T. Yu.; Orlov, V. M.; Miroshnichenko, M. N.; Kolosov, V. N.

2014-07-01

The effect of the granulation and heat treatment of sodium-reduced tantalum powders with a specific surface area of 2.5-3.6 m2/g on the bulk density, the powder flow time, and the specific surface area of the powders and the specific capacitance of the anodes made of them is studied. It is shown that heat treatment of a granulated powder in vacuum at 1100°C or in a mixture with magnesium at 800°C makes it possible to achieve the required powder flow time.

The effect of Ca doping on specific heat of YCoO{sub 3} cobaltate

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

Thakur, Rasna, E-mail: rasnathakur@yahoo.com; Thakur, Rajesh K., E-mail: thakur.rajesh2009@gmail.com; Gaur, N. K., E-mail: srl-nkgaur@yahoo.co.in

2016-05-06

We have investigated the thermodynamic properties of Y{sub 1-x}Ca{sub x}CoO{sub 3} (0.0≤x≤0.1) perovskites by means of a modified rigid ion model (MRIM). The variations of specific heat at wide temperatures 1 K ≤ T ≤ 1000 K are reported. Also, the effect of lattice distortions on the elastic and thermal properties of pure and Ca doped cobaltates has been studied by an atomistic approach. Besides, we have reported bulk modulus (B), cohesive energy (ϕ), molecular force constant (f), Reststrahlen frequency (υ), Debye temperature (θ{sub D}), Gruneisen parameter (γ) and specific heat (C). It is found that the present model has a promisemore » to predict the thermodynamic properties of other perovskites as well.« less

Convective Heat Transfer in the Reusable Solid Rocket Motor of the Space Transportation System

NASA Technical Reports Server (NTRS)

Ahmad, Rashid A.; Cash, Stephen F. (Technical Monitor)

2002-01-01

This simulation involved a two-dimensional axisymmetric model of a full motor initial grain of the Reusable Solid Rocket Motor (RSRM) of the Space Transportation System (STS). It was conducted with CFD (computational fluid dynamics) commercial code FLUENT. This analysis was performed to: a) maintain continuity with most related previous analyses, b) serve as a non-vectored baseline for any three-dimensional vectored nozzles, c) provide a relatively simple application and checkout for various CFD solution schemes, grid sensitivity studies, turbulence modeling and heat transfer, and d) calculate nozzle convective heat transfer coefficients. The accuracy of the present results and the selection of the numerical schemes and turbulence models were based on matching the rocket ballistic predictions of mass flow rate, head end pressure, vacuum thrust and specific impulse, and measured chamber pressure drop. Matching these ballistic predictions was found to be good. This study was limited to convective heat transfer and the results compared favorably with existing theory. On the other hand, qualitative comparison with backed-out data of the ratio of the convective heat transfer coefficient to the specific heat at constant pressure was made in a relative manner. This backed-out data was devised to match nozzle erosion that was a result of heat transfer (convective, radiative and conductive), chemical (transpirating), and mechanical (shear and particle impingement forces) effects combined.

Role of redox homeostasis in thermo-tolerance under a climate change scenario

PubMed Central

de Pinto, Maria Concetta; Locato, Vittoria; Paradiso, Annalisa; De Gara, Laura

2015-01-01

Background Climate change predictions indicate a progressive increase in average temperatures and an increase in the frequency of heatwaves, which will have a negative impact on crop productivity. Over the last decade, a number of studies have addressed the question of how model plants or specific crops modify their metabolism when exposed to heat stress. Scope This review provides an overview of the redox pathways that contribute to how plants cope with heat stress. The focus is on the role of reactive oxygen species (ROS), redox metabolites and enzymes in the signalling pathways leading to the activation of defence responses. Additional attention is paid to the regulating mechanisms that lead to an increase in specific ROS-scavenging systems during heat stress, which have been studied in different model systems. Finally, increasing thermo-tolerance in model and crop plants by exposing them to heat acclimation or to exogenous treatments is discussed. Conclusions Although there is clear evidence that several strategies are specifically activated according to the intensity and the duration of heat stress, as well as the capacity of the different species or genotypes to overcome stress, an alteration in redox homeostasis seems to be a common event. Different mechanisms that act to enhance redox systems enable crops to overcome heat stress more effectively. Knowledge of thermo-tolerance within agronomic biodiversity is thus of key importance to enable researchers to identify new strategies for overcoming the impacts of climate change, and for decision-makers in planning for an uncertain future with new choices and options open to them. PMID:26034009

EEG frequency tagging using ultra-slow periodic heat stimulation of the skin reveals cortical activity specifically related to C fiber thermonociceptors

PubMed Central

Colon, Elisabeth; Liberati, Giulia; Mouraux, André

2017-01-01

The recording of event-related brain potentials triggered by a transient heat stimulus is used extensively to study nociception and diagnose lesions or dysfunctions of the nociceptive system in humans. However, these responses are related exclusively to the activation of a specific subclass of nociceptive afferents: quickly-adapting thermonociceptors. In fact, except if the activation of Aδ fibers is avoided or if A fibers are blocked, these responses specifically reflect activity triggered by the activation of Type 2 quickly-adapting A fiber mechano-heat nociceptors (AMH-2). Here, we propose a novel method to isolate, in the human electroencephalogram (EEG), cortical activity related to the sustained periodic activation of heat-sensitive thermonociceptors, using very slow (0.2 Hz) and long-lasting (75 s) sinusoidal heat stimulation of the skin between baseline and 50°C. In a first experiment, we show that when such long-lasting thermal stimuli are applied to the hand dorsum of healthy volunteers, the slow rises and decreases of skin temperature elicit a consistent periodic EEG response at 0.2 Hz and its harmonics, as well as a periodic modulation of the magnitude of theta, alpha and beta band EEG oscillations. In a second experiment, we demonstrate using an A fiber block that these EEG responses are predominantly conveyed by unmyelinated C fiber nociceptors. The proposed approach constitutes a novel mean to study C fiber function in humans, and to explore the cortical processing of tonic heat pain in physiological and pathological conditions. PMID:27871921

SPECIFIC HEAT DATA ANALYSIS PROGRAM FOR THE IBM 704 DIGITAL COMPUTER

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

Roach, P.R.

1962-01-01

A computer program was developed to calculate the specific heat of a substance in the temperature range from 0.3 to 4.2 deg K, given temperature calibration data for a carbon resistance thermometer, experimental temperature drift, and heating period data. The speciftc heats calculated from these data are then fitted by a curve by the methods of least squares and the specific heats are corrected for the effect of the curvature of the data. The method, operation, program details, and program stops are discussed. A program listing is included. (M.C.G.)

49 CFR 179.220-11 - Postweld heat treatment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Postweld heat treatment. 179.220-11 Section 179... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-11 Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld...

49 CFR 179.220-11 - Postweld heat treatment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Postweld heat treatment. 179.220-11 Section 179... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-11 Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld...

49 CFR 179.220-11 - Postweld heat treatment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Postweld heat treatment. 179.220-11 Section 179... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-11 Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld...

49 CFR 179.100-10 - Postweld heat treatment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Postweld heat treatment. 179.100-10 Section 179... Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-10 Postweld heat... heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars...

Specific heat and Nernst effect of electron-doped cuprate superconductors

NASA Astrophysics Data System (ADS)

Balci, Hamza

This thesis consists of two separate studies on Pr2- xCexCuO4 (PCCO), a member of the electron-doped high temperature cuprate superconductor family: specific heat and the Nernst effect. We measured the specific heat of PCCO single crystals in order to probe the symmetry of the superconducting order parameter, to study the effect of oxygen reduction (annealing) on bulk properties of the crystals, and to determine proper ties like the condensation energy and the thermodynamic critical field. The order parameter symmetry has been established to be d-wave in the hole-doped cuprates. Experiments performed on electron-doped cuprates show conflicting results. Different experiments suggest s-wave symmetry, d-wave symmetry, or a transition from d-wave to s-wave symmetry with increasing cerium doping. However, most of these experiments are surface sensitive experiments. Specific heat, as a bulk method of probing the gap symmetry is essential in order to convincingly determine the gap symmetry. Our data proposes a way to reconcile all these conflicting results regarding the gap symmetry. In addition, prior specific heat measurements attempting to determine thermodynamic properties like the condensation energy were not successful due to inefficient methods of data analysis or poor sample quality. With improvements on sample quality and data analysis, we reliably determined these properties. The second part of this thesis is a study of the Nernst effect in PCCO thin films with different cerium dopings. We probed the superconducting fluctuations, studied transport phenomena in the normal state, and accurately measured H c2 by using the Nernst effect. After the discovery of the anomalous Nernst effect in the normal state of the hole-doped cuprates, many alternative explanations have been proposed. Vortex-like excitations above Tc, superconducting fluctuations, AFM fluctuations, and preformed Cooper pairs are some of these proposals. The electron-doped cuprates, due to their significant differences from the hole-doped cuprates in terms of coherence length and the phase stiffness temperature (a measure of superfluid density) are the ideal materials to test these ideas. Our data on the electron-doped cuprates does not show any anomalous Nernst effect, and hence it supports the superconducting fluctuations picture among the various proposals.

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.

24 CFR 3280.509 - Criteria in absence of specific data.

Code of Federal Regulations, 2010 CFR

2010-04-01

... between the duct and the insulation, heat loss/gain need not be calculated if the cavity in which the duct... § 3280.509 Criteria in absence of specific data. In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used: (a) Infiltration heat loss. In the absence...

24 CFR 3280.509 - Criteria in absence of specific data.

Code of Federal Regulations, 2011 CFR

2011-04-01

... between the duct and the insulation, heat loss/gain need not be calculated if the cavity in which the duct... § 3280.509 Criteria in absence of specific data. In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used: (a) Infiltration heat loss. In the absence...

24 CFR 3280.509 - Criteria in absence of specific data.

Code of Federal Regulations, 2013 CFR

2013-04-01

... between the duct and the insulation, heat loss/gain need not be calculated if the cavity in which the duct... § 3280.509 Criteria in absence of specific data. In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used: (a) Infiltration heat loss. In the absence...

24 CFR 3280.509 - Criteria in absence of specific data.

Code of Federal Regulations, 2012 CFR

2012-04-01

... between the duct and the insulation, heat loss/gain need not be calculated if the cavity in which the duct... § 3280.509 Criteria in absence of specific data. In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used: (a) Infiltration heat loss. In the absence...

Thermophysical Properties of Fluid Latent Heat Storage Material using Urea-Water Mixture

NASA Astrophysics Data System (ADS)

Hokamura, Taku; Ohkubo, Hidetoshi; Ashizawa, Kiyonori

This study is concerned with the measurement of thermophysical properties of a urea-water mixture with the aim of adopting the mixture as a latent heat storage material for air-conditioning systems. The urea-water mixture is made of natural substances and has a good fluidity. The urea concentration in the mixture was controlled by measuring the refractive index of the mixture. Being a multi-component substance, a urea-water solution has a liquid-solid co-existent phase on a phase-diagram. Therefore, the liquidus temperature was measured to establish a relationship between the fraction of the solid-phase and temperature. Furthermore, apparent values of specific heat and coefficient of viscosity were measured in the two-phase region where the solid phase is ice. The apparent specific heat and coefficient of viscosity were measure by using an adiabatic calorimeter and a stirring torque meter respectively. The results revealed that the urea-water mixture can probably be used as a latent heat storage material of good fluidity.

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

Alfheim, I.; Ramdahl, T.

The aims of the Scandinavian research programs dealing with pollution from wood heating are: To characterize the emissions from the most commonly used stoves burning typical Scandinavian wood. In this work the emphasis has been on the characterization of organic compounds in the emissions and especially on the identification of compounds which may have mutagenic effects; To identify compounds which are specific for wood combustion emission and thus can be used as marker compounds in ambient air studies; To assess the contribution of specific pollutants, i.e., polycyclic aromatic compounds and mutagens, from wood heating to ambient air; To study themore » influence of wood heating on indoor air quality; and To support the development of stoves with less polluting emissions. This paper presents a brief overview of the work done and the results obtained so far within the Norwegian project and in a joint Nordic project.« less

Superconductivity in LaPd2Al2-xGax compounds

NASA Astrophysics Data System (ADS)

Klicpera, M.; Pásztorová, J.; Javorský, P.

2014-08-01

The superconductivity in LaPd2Al2-xGax compounds was studied by means of electrical resistivity and specific heat measurements. The concentration development of the superconducting properties was revealed. The measured data deviate significantly from the Bardeen-Cooper-Schrieffer theory predictions and are discussed in the context of unconventional superconductivity. The electronic specific heat below {{T}_{SC}} follows almost quadratic temperature dependence, which might indicate an axial state with line nodes in the superconducting gap structure.

Specific heat in KFe2As2 in zero and applied magnetic field

NASA Astrophysics Data System (ADS)

Kim, J. S.; Kim, E. G.; Stewart, G. R.; Chen, X. H.; Wang, X. F.

2011-05-01

The specific heat down to 0.08 K of the iron pnictide superconductor KFe2As2 was measured on a single-crystal sample with a residual resistivity ratio of ˜650, with a Tconset determined by a specific heat of 3.7 K. The zero-field normal-state specific heat divided by temperature, C/T, was extrapolated from above Tc to T=0 by insisting on agreement between the extrapolated normal-state entropy at Tc, Snextrap(Tc), and the measured superconducting-state entropy at Tc, Ssmeas(Tc), since for a second-order phase transition the two entropies must be equal. This extrapolation would indicate that this rather clean sample of KFe2As2 exhibits non-Fermi-liquid behavior; i.e., C/T increases at low temperatures, in agreement with the reported non-Fermi-liquid behavior in the resistivity. However, specific heat as a function of magnetic field shows that the shoulder feature around 0.7 K, which is commonly seen in KFe2As2 samples, is not evidence for a second superconducting gap as has been previously proposed but instead is due to an unknown magnetic impurity phase, which can affect the entropy balance and the extrapolation of the normal-state specific heat. This peak (somewhat larger in magnitude) with similar field dependence is also found in a less pure sample of KFe2As2, with a residual resistivity ratio of only 90 and Tconset=3.1 K. These data, combined with the measured normal-state specific heat in field to suppress superconductivity, allow the conclusion that an increase in the normal-state specific heat as T→0 is in fact not seen in KFe2As2; i.e., Fermi-liquid behavior is observed.

Calorimetric measurements on Li4C60 and Na4C60

NASA Astrophysics Data System (ADS)

Inaba, Akira; Miyazaki, Yuji; Michałowski, Paweł P.; Gracia-Espino, Eduardo; Sundqvist, Bertil; Wâgberg, Thomas

2015-04-01

We show specific heat data for Na4C60 and Li4C60 in the range 0.4-350 K for samples characterized by Raman spectroscopy and X-ray diffraction. At high temperatures, the two different polymer structures have very similar specific heats both in absolute values and in general trend. The specific heat data are compared with data for undoped polymeric and pristine C60. At high temperatures, a difference in specific heat between the intercalated and undoped C60 polymers of 100 J K-1 mol-1 is observed, in agreement with the Dulong-Petit law. At low temperatures, the specific heat data for Li4C60 and Na4C60 are modified by the stiffening of vibrational and librational molecular motion induced by the polymer bonds. The covalent twin bonds in Li4C60 affect these motions to a somewhat higher degree than the single intermolecular bonds in Na4C60. Below 1 K, the specific heats of both materials become linear in temperature, as expected from the effective dimensionality of the structure. The contribution to the total specific heat from the inserted metal ions can be well described by Einstein functions with TE = 386 K for Li4C60 and TE = 120 K for Na4C60, but for both materials we also observe a Schottky-type contribution corresponding to a first approximation to a two-level system with ΔE = 9.3 meV for Li4C60 and 3.1 meV for Na4C60, probably associated with jumps between closely spaced energy levels inside "octahedral-type" ionic sites. Static magnetic fields up to 9 T had very small effects on the specific heat below 10 K.

Heat transfer in a conical porous medium due to inner and top surface heating: Effect of radius ratio

NASA Astrophysics Data System (ADS)

Ahamad, N. Ameer; Khan, T. M. Yunus

2018-05-01

The present study investigates the effect of radius ratio and Rayleigh number on beat transfer characteristics of an annular cone subjected to two side heating and one side cooling. Finite element method is used to convert the partial differential equations into algebraic equations. The resulting equations are solved with the help of in-house computer code developed for specific purpose of heat transfer in conical porous medium. The results are discussed with respect to the radius ratio and Rayleigh number.

Temperature-dependent thermal properties of ex vivo liver undergoing thermal ablation.

PubMed

Guntur, Sitaramanjaneya Reddy; Lee, Kang Il; Paeng, Dong-Guk; Coleman, Andrew John; Choi, Min Joo

2013-10-01

Thermotherapy uses a heat source that raises temperatures in the target tissue, and the temperature rise depends on the thermal properties of the tissue. Little is known about the temperature-dependent thermal properties of tissue, which prevents us from accurately predicting the temperature distribution of the target tissue undergoing thermotherapy. The present study reports the key thermal parameters (specific heat capacity, thermal conductivity and heat diffusivity) measured in ex vivo porcine liver while being heated from 20 ° C to 90 ° C and then naturally cooled down to 20 ° C. The study indicates that as the tissue was heated, all the thermal parameters resulted in plots with asymmetric quasi-parabolic curves with temperature, being convex downward with their minima at the turning temperature of 35-40 ° C. The largest change was observed for thermal conductivity, which decreased by 9.6% from its initial value (at 20 ° C) at the turning temperature (35 ° C) and rose by 45% at 90 ° C from its minimum (at 35 ° C). The minima were 3.567 mJ/(m(3) ∙ K) for specific heat capacity, 0.520 W/(m.K) for thermal conductivity and 0.141 mm(2)/s for thermal diffusivity. The minimum at the turning temperature was unique, and it is suggested that it be taken as a characteristic value of the thermal parameter of the tissue. On the other hand, the thermal parameters were insensitive to temperature and remained almost unchanged when the tissue cooled down, indicating that their variations with temperature were irreversible. The rate of the irreversible rise at 35 ° C was 18% in specific heat capacity, 40% in thermal conductivity and 38.3% in thermal diffusivity. The study indicates that the key thermal parameters of ex vivo porcine liver vary largely with temperature when heated, as described by asymmetric quasi-parabolic curves of the thermal parameters with temperature, and therefore, substantial influence on the temperature distribution of the tissue undergoing thermotherapy is expected. 2013. Published by Elsevier Inc

Solar heating system design package for a single-family residence at William O'Brien State Park, Minnesota

NASA Technical Reports Server (NTRS)

1977-01-01

The plans, specifications, cost trade studies, and verification status of a prototype solar heating and hot water system for the Minnesota Department of Natural Resources's single-family dwelling located at O'Brien State Park, 30 miles east of Minneapolis, Minnesota are presented.

24 CFR 3280.509 - Criteria in absence of specific data.

Code of Federal Regulations, 2014 CFR

2014-04-01

... is an air space of at least 1/2 inch between the duct and the insulation, heat loss/gain need not be..., 2013. In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used: (a) Infiltration heat loss. In the absence of measured infiltration heat loss data...

Distinct CD4+-T-cell responses to live and heat-inactivated Aspergillus fumigatus conidia.

PubMed

Rivera, Amariliz; Van Epps, Heather L; Hohl, Tobias M; Rizzuto, Gabrielle; Pamer, Eric G

2005-11-01

Aspergillus fumigatus is an important fungal pathogen that causes invasive pulmonary disease in immunocompromised hosts. Respiratory exposure to A. fumigatus spores also causes allergic bronchopulmonary aspergillosis, a Th2 CD4+-T-cell-mediated disease that accompanies asthma. The microbial factors that influence the differentiation of A. fumigatus-specific CD4+ T lymphocytes into Th1 versus Th2 cells remain incompletely defined. We therefore examined CD4+-T-cell responses of immunologically intact mice to intratracheal challenge with live or heat-inactivated A. fumigatus spores. Live but not heat-inactivated fungal spores resulted in recruitment of gamma interferon (IFN-gamma)-producing, fungus-specific CD4+ T cells to lung airways, achieving A. fumigatus-specific frequencies exceeding 5% of total CD4+ T cells. While heat-inactivated spores did not induce detectable levels of IFN-gamma-producing, A. fumigatus-specific CD4+ T cells in the airways, they did prime CD4+ T-cell responses in draining lymph nodes that produced greater amounts of interleukin 4 (IL-4) and IL-13 than T cells responding to live conidia. While immunization with live fungal spores induced antibody responses, we found a marked decrease in isotype-switched, A. fumigatus-specific antibodies in sera of mice following immunization with heat-inactivated spores. Our studies demonstrate that robust Th1 T-cell and humoral responses are restricted to challenge with fungal spores that have the potential to germinate and cause invasive infection. How the adaptive immune system distinguishes between metabolically active and inactive fungal spores remains an important question.

Specific interface area and self-stirring in a two-liquid system experiencing intense interfacial boiling below the bulk boiling temperatures of both components

NASA Astrophysics Data System (ADS)

Goldobin, Denis S.; Pimenova, Anastasiya V.

2017-04-01

We present an approach to theoretical assessment of the mean specific interface area (δ S/δ V) for a well-stirred system of two immiscible liquids experiencing interfacial boiling. The assessment is based on the balance of transformations of mechanical energy and the laws of the momentum and heat transfer in the turbulent boundary layer. The theory yields relations between the specific interface area and the characteristics of the system state. In particular, this allows us to derive the equations of self-cooling dynamics of the system in the absence of external heat supply. The results provide possibility for constructing a self-contained mathematical description of the process of interfacial boiling. In this study, we assume the volume fractions of two components to be similar as well as the values of their kinematic viscosity and molecular heat diffusivity.

Preliminary design package for prototype solar heating and cooling systems

NASA Technical Reports Server (NTRS)

1978-01-01

A summary is given of the preliminary analysis and design activity on solar heating and cooling systems. The analysis was made without site specific data other than weather; therefore, the results indicate performance expected under these special conditions. Major items include a market analysis, design approaches, trade studies and other special data required to evaluate the preliminary analysis and design. The program calls for the development and delivery of eight prototype solar heating and cooling systems for installation and operational test. Two heating and six heating and cooling units will be delivered for Single Family Residences, Multiple-family Residences and commercial applications.

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications

NASA Astrophysics Data System (ADS)

Lasfargues, Mathieu; Bell, Andrew; Ding, Yulong

2016-06-01

In this study, TiO2 nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO4) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

Relative Role of Horizontal and Vertical Processes in Arctic Amplification

NASA Astrophysics Data System (ADS)

Kim, K. Y.

2017-12-01

The physical mechanism of Arctic amplification is still controversial. Specifically, relative role of vertical processes resulting from the reduction of sea ice in the Barents-Kara Seas is not clearly understood in comparison with the horizontal advection of heat and moisture. Using daily data, heat and moisture budgets are analyzed during winter (Dec. 1-Feb. 28) over the region of sea ice reduction in order to delineate the relative roles of horizontal and vertical processes. Detailed heat and moisture budgets in the atmospheric column indicate that the vertical processes, release of turbulent heat fluxes and evaporation, are a major contributor to the increased temperature and specific humidity over the Barents-Kara Seas. In addition, greenhouse effect caused by the increased specific humidity, also plays an important role in Arctic amplification. Horizontal processes such as advection of heat and moisture are the primary source of variability (fluctuations) in temperature and specific humidity in the atmospheric column. Advection of heat and moisture, on the other hand, is little responsible for the net increase in temperature and specific humidity over the Barents-Kara Seas.

Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Ranoo, Surojit; Philip, John

2017-11-01

Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ~25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and the results are compared using a lumped system thermal model. The various uncertainties involved in SAR estimation are categorized as material uncertainties, thermodynamic uncertainties and parametric uncertainties. The adiabatic reconstruction is found to decrease the uncertainties in SAR measurement by approximately three times. Additionally, a set of experimental guidelines for accurate SAR estimation using adiabatic reconstruction protocol is also recommended. These results warrant a universal experimental and data analysis protocol for SAR measurements during field induced heating of magnetic fluids under non-adiabatic conditions.

Effect of high energy electron beam (10MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite.

PubMed

Soltani, Z; Ziaie, F; Ghaffari, M; Beigzadeh, A M

2017-02-01

In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10MeV electron beam at doses of 75 to 250kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100°C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite. Copyright © 2016 Elsevier B.V. All rights reserved.

A Comprehensive Study of a Micro-Channel Heat Sink Using Integrated Thin-Film Temperature Sensors

PubMed Central

Wang, Tao; Wang, Jiejun; He, Jian; Wu, Chuangui; Luo, Wenbo; Shuai, Yao; Zhang, Wanli; Chen, Xiancai; Zhang, Jian; Lin, Jia

2018-01-01

A micro-channel heat sink is a promising cooling method for high power integrated circuits (IC). However, the understanding of such a micro-channel device is not sufficient, because the tools for studying it are very limited. The details inside the micro-channels are not readily available. In this letter, a micro-channel heat sink is comprehensively studied using the integrated temperature sensors. The highly sensitive thin film temperature sensors can accurately monitor the temperature change in the micro-channel in real time. The outstanding heat dissipation performance of the micro-channel heat sink is proven in terms of maximum temperature, cooling speed and heat resistance. The temperature profile along the micro-channel is extracted, and even small temperature perturbations can be detected. The heat source formed temperature peak shifts towards the flow direction with the increasing flow rate. However, the temperature non-uniformity is independent of flow rate, but solely dependent on the heating power. Specific designs for minimizing the temperature non-uniformity are necessary. In addition, the experimental results from the integrated temperature sensors match the simulation results well. This can be used to directly verify the modeling results, helping to build a convincing simulation model. The integrated sensor could be a powerful tool for studying the micro-channel based heat sink. PMID:29351248

A Comprehensive Study of a Micro-Channel Heat Sink Using Integrated Thin-Film Temperature Sensors.

PubMed

Wang, Tao; Wang, Jiejun; He, Jian; Wu, Chuangui; Luo, Wenbo; Shuai, Yao; Zhang, Wanli; Chen, Xiancai; Zhang, Jian; Lin, Jia

2018-01-19

A micro-channel heat sink is a promising cooling method for high power integrated circuits (IC). However, the understanding of such a micro-channel device is not sufficient, because the tools for studying it are very limited. The details inside the micro-channels are not readily available. In this letter, a micro-channel heat sink is comprehensively studied using the integrated temperature sensors. The highly sensitive thin film temperature sensors can accurately monitor the temperature change in the micro-channel in real time. The outstanding heat dissipation performance of the micro-channel heat sink is proven in terms of maximum temperature, cooling speed and heat resistance. The temperature profile along the micro-channel is extracted, and even small temperature perturbations can be detected. The heat source formed temperature peak shifts towards the flow direction with the increasing flow rate. However, the temperature non-uniformity is independent of flow rate, but solely dependent on the heating power. Specific designs for minimizing the temperature non-uniformity are necessary. In addition, the experimental results from the integrated temperature sensors match the simulation results well. This can be used to directly verify the modeling results, helping to build a convincing simulation model. The integrated sensor could be a powerful tool for studying the micro-channel based heat sink.

Radiatively coupled thermionic and thermoelectric power system concept

NASA Technical Reports Server (NTRS)

Shimada, K.; Ewell, R.

1981-01-01

The study presented showed that the large power systems (about 100 kW) utilizing radiatively coupled thermionic or thermoelectric converters could be designed so that the power subsystem could be contained in a Space Shuttle bay as a part of an electrically propelled spacecraft. The radiatively coupled system requires a large number of individual converters since the transferred heat is smaller than with the conductively coupled system, but the advantages of the new system indicates merit for further study. The advantages are (1) good electrical isolation between converters and the heat source, (2) physical separation of converters from the heat source (making the system fabrication manageable), and (3) elimination of radiator heat pipes, which are required in an all-heat-pipe power system. In addition, the specific weight of the radiatively coupled power systems favorably compares with that of the all-heat-pipe systems.

Methodological specifics of the study of micro HPP based on internal combustion engines with air cooling and cogeneration

NASA Astrophysics Data System (ADS)

Shchinnikov, P. A.; Tomilov, V. G.; Sinelnikov, D. S.

2017-01-01

The article considers some aspects of the research methodology of micro heat power plants based on internal combustion engines with air cooling and cogeneration based on energy balance equations and the laws of heat transfer. The research is conducted for such a setup based on the Hitachi internal combustion engine with 2.4 kW capacity. It has shown the efficiency of cogeneration use in the form of useful heat flow from air, cooling the cylinder head, with its further heating by utilizing the heat of flue gases in an additional plate heat exchanger. It has been shown that the cogeneration can save fuel costs 3-10 times compared with heat guns, depending on the duration of the setup use.

Exposure of Lactating Dairy Cows to Acute Pre-Ovulatory Heat Stress Affects Granulosa Cell-Specific Gene Expression Profiles in Dominant Follicles

PubMed Central

Vanselow, Jens; Vernunft, Andreas; Koczan, Dirk; Spitschak, Marion; Kuhla, Björn

2016-01-01

High environmental temperatures induce detrimental effects on various reproductive processes in cattle. According to the predicted global warming the number of days with unfavorable ambient temperatures will further increase. The objective of this study was to investigate effects of acute heat stress during the late pre-ovulatory phase on morphological, physiological and molecular parameters of dominant follicles in cycling cows during lactation. Eight German Holstein cows in established lactation were exposed to heat stress (28°C) or thermoneutral conditions (15°C) with pair-feeding for four days. After hormonal heat induction growth of the respective dominant follicles was monitored by ultrasonography for two days, then an ovulatory GnRH dose was given and follicular steroid hormones and granulosa cell-specific gene expression profiles were determined 23 hrs thereafter. The data showed that the pre-ovulatory growth of dominant follicles and the estradiol, but not the progesterone concentrations tended to be slightly affected. mRNA microarray and hierarchical cluster analysis revealed distinct expression profiles in granulosa cells derived from heat stressed compared to pair-fed animals. Among the 255 affected genes heatstress-, stress- or apoptosis associated genes were not present. But instead, we found up-regulation of genes essentially involved in G-protein coupled signaling pathways, extracellular matrix composition, and several members of the solute carrier family as well as up-regulation of FST encoding follistatin. In summary, the data of the present study show that acute pre-ovulatory heat stress can specifically alter gene expression profiles in granulosa cells, however without inducing stress related genes and pathways and suggestively can impair follicular growth due to affecting the activin-inhibin-follistatin system. PMID:27532452

Exposure of Lactating Dairy Cows to Acute Pre-Ovulatory Heat Stress Affects Granulosa Cell-Specific Gene Expression Profiles in Dominant Follicles.

PubMed

Vanselow, Jens; Vernunft, Andreas; Koczan, Dirk; Spitschak, Marion; Kuhla, Björn

2016-01-01

High environmental temperatures induce detrimental effects on various reproductive processes in cattle. According to the predicted global warming the number of days with unfavorable ambient temperatures will further increase. The objective of this study was to investigate effects of acute heat stress during the late pre-ovulatory phase on morphological, physiological and molecular parameters of dominant follicles in cycling cows during lactation. Eight German Holstein cows in established lactation were exposed to heat stress (28°C) or thermoneutral conditions (15°C) with pair-feeding for four days. After hormonal heat induction growth of the respective dominant follicles was monitored by ultrasonography for two days, then an ovulatory GnRH dose was given and follicular steroid hormones and granulosa cell-specific gene expression profiles were determined 23 hrs thereafter. The data showed that the pre-ovulatory growth of dominant follicles and the estradiol, but not the progesterone concentrations tended to be slightly affected. mRNA microarray and hierarchical cluster analysis revealed distinct expression profiles in granulosa cells derived from heat stressed compared to pair-fed animals. Among the 255 affected genes heatstress-, stress- or apoptosis associated genes were not present. But instead, we found up-regulation of genes essentially involved in G-protein coupled signaling pathways, extracellular matrix composition, and several members of the solute carrier family as well as up-regulation of FST encoding follistatin. In summary, the data of the present study show that acute pre-ovulatory heat stress can specifically alter gene expression profiles in granulosa cells, however without inducing stress related genes and pathways and suggestively can impair follicular growth due to affecting the activin-inhibin-follistatin system.

Study of heat generation and cutting force according to minimization of grain size (500 nm to 180 nm) of WC ball endmill using FEM

NASA Astrophysics Data System (ADS)

Byeon, J. H.; Ahmed, F.; Ko, T. J.; lee, D. K.; Kim, J. S.

2018-03-01

As the industry develops, miniaturization and refinement of products are important issues. Precise machining is required for cutting, which is a typical method of machining a product. The factor determining the workability of the cutting process is the material of the tool. Tool materials include carbon tool steel, alloy tool steel, high-speed steel, cemented carbide, and ceramics. In the case of a carbide material, the smaller the particle size, the better the mechanical properties with higher hardness, strength and toughness. The specific heat, density, and thermal diffusivity are also changed through finer particle size of the material. In this study, finite element analysis was performed to investigate the change of heat generation and cutting power depending on the physical properties (specific heat, density, thermal diffusivity) of tool material. The thermal conductivity coefficient was obtained by measuring the thermal diffusivity, specific heat, and density of the material (180 nm) in which the particle size was finer and the particle material (0.05 μm) in the conventional size. The coefficient of thermal conductivity was calculated as 61.33 for 180nm class material and 46.13 for 0.05μm class material. As a result of finite element analysis using this value, the average temperature of exothermic heat of micronized particle material (180nm) was 532.75 °C and the temperature of existing material (0.05μm) was 572.75 °C. Cutting power was also compared but not significant. Therefore, if the thermal conductivity is increased through particle refinement, the surface power can be improved and the tool life can be prolonged by lowering the temperature generated in the tool during machining without giving a great influence to the cutting power.

Influence of kondo effect on the specific heat jump of anisotropic superconductors

NASA Astrophysics Data System (ADS)

Yoksan, S.

1986-01-01

A calculation for the specific heat jump of an anisotropic superconductor with Kondo impurities is presented. The impurities are treated within the Matsuura - Ichinose - Nagaoka framework and the anisotropy effect is described by the factorizable model of Markowitz and Kadanoff. We give explicit expressions for the change in specific heat jump due to anisotropy and impurities which can be tested experimentally.

Unified trade-off optimization for general heat devices with nonisothermal processes.

PubMed

Long, Rui; Liu, Wei

2015-04-01

An analysis of the efficiency and coefficient of performance (COP) for general heat engines and refrigerators with nonisothermal processes is conducted under the trade-off criterion. The specific heat of the working medium has significant impacts on the optimal configurations of heat devices. For cycles with constant specific heat, the bounds of the efficiency and COP are found to be the same as those obtained through the endoreversible Carnot ones. However, they are independent of the cycle time durations. For cycles with nonconstant specific heat, whose dimensionless contact time approaches infinity, the general alternative upper and lower bounds of the efficiency and COP under the trade-off criteria have been proposed under the asymmetric limits. Furthermore, when the dimensionless contact time approaches zero, the endoreversible Carnot model is recovered. In addition, the efficiency and COP bounds of different kinds of actual heat engines and refrigerators have also been analyzed. This paper may provide practical insight for designing and operating actual heat engines and refrigerators.

Studies of Nucleation and Growth, Specific Heat and Viscosity of Undercooled Melts of Quasicrystals and Polytetrehedral-Phase-Forming Alloys

NASA Technical Reports Server (NTRS)

2003-01-01

By investigating the properties of quasicrystals and quasicrystal-forming liquid alloys, we may determine the role of ordering of the liquid phase in the formation of quasicrystals, leading to a better fundamental understanding of both the quasicrystal and the liquid. A quasicrystal is solid characterized by a symmetric but non-periodic arrangement of atoms, usually in the form of an icosahedron (12 atoms, 20 triangular faces). It is theorized that the short-range order in liquids takes this same form. The degree of ordering depends on the temperature of the liquid, and affects many of the liquid s properties, including specific heat, viscosity, and electrical resistivity. The MSFC role in this project includes solidification studies, phase diagram determination, and thermophysical property measurements on the liquid quasicrystal-forming alloys, all by electrostatic levitation (ESL). The viscosity of liquid quasicrystal-forming alloys is measured by the oscillating drop method, both in the stable and undercooled liquid state. The specific heat of solid, undercooled liquid, and stable liquid are measured by the radiative cooling rate of the droplets.

Energy Dissipation in Ex-Vivo Porcine Liver during Electrosurgery

PubMed Central

Karaki, Wafaa; Akyildiz, Ali; De, Suvranu

2017-01-01

This paper explores energy dissipation in ex-vivo liver tissue during radiofrequency current excitation with application in electrosurgery. Tissue surface temperature for monopolar electrode configuration is measured using infrared thermometry. The experimental results are fitted to a finite element model for transient heat transfer taking into account energy storage and conduction in order to extract information about “apparent” specific heat, which encompasses storage and phase change. The average apparent specific heat determined for low temperatures is in agreement with published data. However, at temperatures approaching the boiling point of water, apparent specific heat increases by a factor of five, indicating that vaporization plays an important role in the energy dissipation through latent heat loss. PMID:27479955

Specific heat of new perovskite-type cobaltates Pr{sub 1-x}Nd{sub x}CoO{sub 3}

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

Thakur, Rasna, E-mail: rasnarishu@gmail.com; Thakur, Rajesh K.; Gaur, N. K.

2016-05-23

Specific heat and Bulk modulus (B) of new perovskite-type cobaltates Pr{sub 1-x}Nd{sub x}CoO{sub 3} has been studied by means of a Modified Rigid Ion Model (MRIM) and Atoms in Molecules (AIM) theory in a wide temperature range (1 K ≤ T ≤1000 K). The effect of Nd doping on the elastic, cohesive and thermal properties of PrCoO{sub 3} have been studied probably for the first time by an atomistic approach. The computed results are in good agreement with the available experimental data.

Heat capacity of high-purity lanthanum

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

Pan, P.H.; Finnemore, D.K.; Bevolo, A.J.

1980-04-01

A study of the specific heat of high-purity single-phase dhcp La shows that this material is an intrinsic type-II superconductor with a kappa of about 2.4. The temperature dependence of the free energy is characteristic of an intermediate coupling superconductor with 2..delta../k/sub B/T/sub c/ approx. = 3.7.

Preliminary design package for prototype solar heating system

NASA Technical Reports Server (NTRS)

1978-01-01

A summary is given of the preliminary analysis and design activity on solar heating systems. The analysis was made without site specific data other than weather; therefore, the results indicate performance expected under these special conditions. Major items include system candidates, design approaches, trade studies and other special data required to evaluate the preliminary analysis and design. The program calls for the development and delivery of eight prototype solar heating and cooling systems for installation and operational test.

Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage (STES). Application Manual

DTIC Science & Technology

2016-11-01

Defense. Reference herein to any specific commercial product , process, or service by trade name, trademark, manufacturer, or otherwise, does not...1 1.3 Cooling-Dominated Buildings and MCAS Beaufort Case Study 4 1.4 Potential Approach for Mitigating Heat Buildup -- Hybrid Geothermal Heat...the ground through another well. This type of system can be very effective, but it requires access to a productive aquifer with associated

Thermodynamic properties of methane hydrate in quartz powder.

PubMed

Voronov, Vitaly P; Gorodetskii, Evgeny E; Safonov, Sergey S

2007-10-04

Using the experimental method of precision adiabatic calorimetry, the thermodynamic (equilibrium) properties of methane hydrate in quartz sand with a grain size of 90-100 microm have been studied in the temperature range of 260-290 K and at pressures up to 10 MPa. The equilibrium curves for the water-methane hydrate-gas and ice-methane hydrate-gas transitions, hydration number, latent heat of hydrate decomposition along the equilibrium three-phase curves, and the specific heat capacity of the hydrate have been obtained. It has been experimentally shown that the equilibrium three-phase curves of the methane hydrate in porous media are shifted to the lower temperature and high pressure with respect to the equilibrium curves of the bulk hydrate. In these experiments, we have found that the specific heat capacity of the hydrate, within the accuracy of our measurements, coincides with the heat capacity of ice. The latent heat of the hydrate dissociation for the ice-hydrate-gas transition is equal to 143 +/- 10 J/g, whereas, for the transition from hydrate to water and gas, the latent heat is 415 +/- 15 J/g. The hydration number has been evaluated in the different hydrate conditions and has been found to be equal to n = 6.16 +/- 0.06. In addition, the influence of the water saturation of the porous media and its distribution over the porous space on the measured parameters has been experimentally studied.

Heat flux measurements of Tb3M series (M=Co, Rh and Ru): Specific heat and magnetocaloric properties

NASA Astrophysics Data System (ADS)

Monteiro, J. C. B.; Lombardi, G. A.; dos Reis, R. D.; Freitas, H. E.; Cardoso, L. P.; Mansanares, A. M.; Gandra, F. G.

2016-12-01

We report on the magnetic properties and magnetocaloric effect (MCE) for the Tb3M series, with M=Co, Rh and Ru, obtained using a heat flux technique. The specific heat of Tb3Co and Tb3Rh are very similar, with a first order type transition occurring around 6 K below the magnetic ordering temperature without any corresponding feature on the magnetization. The slightly enhanced electronic specific heat, the Debye temperature around 150 K and the presence of the magnetic specific heat well above the ordering temperature are also characteristic of many other compounds of the R3M family (R=Rare Earth). The specific heat for Tb3Ru, however, presents two peaks at 37 K and 74 K. The magnetization shows that below the first peak the system presents an antiferromagnetic behavior and is paramagnetic above 74 K. We obtained a magnetocaloric effect for M=Co and Rh, -∆S=12 J/kg K, but for Tb3Ru it is less than 3 J/kg K (μ0∆H=5 T). We believe that the experimental results show that the MCE is directly related with the process of hybridization of the (R)5d-(M)d electrons that occurs in the R3M materials.

Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

NASA Astrophysics Data System (ADS)

Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

2018-03-01

In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

Code of Federal Regulations, 2011 CFR

2011-07-01

... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... and for a flow monitoring system and an O2 or CO2 diluent gas monitoring system to measure heat input...

Dielectric and specific heat relaxations in vapor deposited glycerol

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

Kasina, A., E-mail: angeline.kasina@fys.kuleuven.be, E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M., E-mail: angeline.kasina@fys.kuleuven.be, E-mail: wubbenhorst@fys.kuleuven.be

2015-12-28

Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of themore » temperature. Heating of the as-deposited glass just above the bulk T{sub g} and subsequent cooling/reheating revealed a step-wise increase in c{sub p} by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at −75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of “MROL glycerol” to its “normal” (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy c{sub p}, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τ{sub cal} from that of normal “bulk” glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs) and conclusively explains the extraordinary high kinetic stability of the MROL state, its specific calorimetric signature, the enhanced strength, and apparent slow-down of the dielectric α-relaxation. In this new picture, the incredibly slow and strengthened dielectric response is ascribed to driven rotational diffusion of whole RPCs, a mechanism that perfectly couples to the relaxation time of the “normal” glycerol fraction. First considerations based on the strength and the retardation of the dielectric RPCs’ response yield independently a size estimate for the RPCs in the order of 4-5 nm. Finally, we have discussed possible crystallisation and reorganisation effects, which give rise to pronounced out-of phase components of the specific heat at higher temperatures.« less

Microchannel Heat Sink with Micro Encapsulated Phase Change Material (MEPCM) Slurry

DTIC Science & Technology

2009-05-31

inlet temperature of the fluid, melting range of PCM and base heat flux. 15. SUBJECT TERMS Phase Change Materials; microchannel cooling; slurry...such as particle concentration, inlet temperature of the fluid, melting range of PCM , base heat flux and base fluid. Nomenclature A Aspect ratio Ab...of fluid, J/kg.K cp,p Specific heat of MEPCM particle, J/kg.K Cp, pcm Specific heat of PCM , J/kg.K D Hydraulic diameter, m d, dp Particle diameter

A preliminary study of the application of HCMM satellite data to define initial and boundary conditions for numerical models: A case study in St. Louis, Missouri

NASA Technical Reports Server (NTRS)

Vukovich, F. M. (Principal Investigator)

1982-01-01

Infrared and visible HCMM data were used to examine the potential application of these data to define initial and boundary conditions for mesoscale numerical models. Various boundary layer models were used to calculate the distribution of the surface heat flux, specific humidity depression (the difference between the specific humidity in the air at approxmately the 10 m level and the specific humidity at the ground), and the eddy vicosity in a 72 km by 72 km area centered about St. Louis, Missouri. Various aspects of the implications of the results on the meteorology of St. Louis are discussed. Overall, the results indicated that a reasonable estimate of the surface heat flux, urban albedo, ground temperature, and specific humidity depression can be obtained using HCMM satellite data. Values of the ground-specific humidity can be obtained if the distribution of the air-specific humidity is available. More research is required in estimating the absolute magnitude of the specific humidity depression because calculations may be sensitive to model parameters.

Transcriptomic analysis of grape (Vitis vinifera L.) leaves during and after recovery from heat stress.

PubMed

Liu, Guo-Tian; Wang, Jun-Fang; Cramer, Grant; Dai, Zhan-Wu; Duan, Wei; Xu, Hong-Guo; Wu, Ben-Hong; Fan, Pei-Ge; Wang, Li-Jun; Li, Shao-Hua

2012-09-28

Grapes are a major fruit crop around the world. Heat stress can significantly reduce grape yield and quality. Changes at the molecular level in response to heat stress and subsequent recovery are poorly understood. To elucidate the effect of heat stress and subsequent recovery on expression of genes by grape leaves representing the classic heat stress response and thermotolerance mechanisms, transcript abundance of grape (Vitis vinifera L.) leaves was quantified using the Affymetrix Grape Genome oligonucleotide microarray (15,700 transcripts), followed by quantitative Real-Time PCR validation for some transcript profiles. We found that about 8% of the total probe sets were responsive to heat stress and/or to subsequent recovery in grape leaves. The heat stress and recovery responses were characterized by different transcriptional changes. The number of heat stress-regulated genes was almost twice the number of recovery-regulated genes. The responsive genes identified in this study belong to a large number of important traits and biological pathways, including cell rescue (i.e., antioxidant enzymes), protein fate (i.e., HSPs), primary and secondary metabolism, transcription factors, signal transduction, and development. We have identified some common genes and heat shock factors (HSFs) that were modulated differentially by heat stress and recovery. Most HSP genes were upregulated by heat stress but were downregulated by the recovery. On the other hand, some specific HSP genes or HSFs were uniquely responsive to heat stress or recovery. The effect of heat stress and recovery on grape appears to be associated with multiple processes and mechanisms including stress-related genes, transcription factors, and metabolism. Heat stress and recovery elicited common up- or downregulated genes as well as unique sets of responsive genes. Moreover, some genes were regulated in opposite directions by heat stress and recovery. The results indicated HSPs, especially small HSPs, antioxidant enzymes (i.e., ascorbate peroxidase), and galactinol synthase may be important to thermotolerance of grape. HSF30 may be a key regulator for heat stress and recovery, while HSF7 and HSF1 may only be specific to recovery. The identification of heat stress or recovery responsive genes in this study provides novel insights into the molecular basis for heat tolerance in grape leaves.

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.

The impact of heat waves on mortality in 9 European cities: results from the EuroHEAT project.

PubMed

D'Ippoliti, Daniela; Michelozzi, Paola; Marino, Claudia; de'Donato, Francesca; Menne, Bettina; Katsouyanni, Klea; Kirchmayer, Ursula; Analitis, Antonis; Medina-Ramón, Mercedes; Paldy, Anna; Atkinson, Richard; Kovats, Sari; Bisanti, Luigi; Schneider, Alexandra; Lefranc, Agnès; Iñiguez, Carmen; Perucci, Carlo A

2010-07-16

The present study aimed at developing a standardized heat wave definition to estimate and compare the impact on mortality by gender, age and death causes in Europe during summers 1990-2004 and 2003, separately, accounting for heat wave duration and intensity. Heat waves were defined considering both maximum apparent temperature and minimum temperature and classified by intensity, duration and timing during summer. The effect was estimated as percent increase in daily mortality during heat wave days compared to non heat wave days in people over 65 years. City specific and pooled estimates by gender, age and cause of death were calculated. The effect of heat waves showed great geographical heterogeneity among cities. Considering all years, except 2003, the increase in mortality during heat wave days ranged from + 7.6% in Munich to + 33.6% in Milan. The increase was up to 3-times greater during episodes of long duration and high intensity. Pooled results showed a greater impact in Mediterranean (+ 21.8% for total mortality) than in North Continental (+ 12.4%) cities. The highest effect was observed for respiratory diseases and among women aged 75-84 years. In 2003 the highest impact was observed in cities where heat wave episode was characterized by unusual meteorological conditions. Climate change scenarios indicate that extreme events are expected to increase in the future even in regions where heat waves are not frequent. Considering our results prevention programs should specifically target the elderly, women and those suffering from chronic respiratory disorders, thus reducing the impact on mortality.

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.

Thermal Properties of Consolidated Granular Salt as a Backfill Material

NASA Astrophysics Data System (ADS)

Paneru, Laxmi P.; Bauer, Stephen J.; Stormont, John C.

2018-03-01

Granular salt has been proposed as backfill material in drifts and shafts of a nuclear waste disposal facility where it will serve to conduct heat away from the waste to the host rock. Creep closure of excavations in rock salt will consolidate (reduce the porosity of) the granular salt. This study involved measuring the thermal conductivity and specific heat of granular salt as a function of porosity and temperature to aid in understanding how thermal properties will change during granular salt consolidation accomplished at pressures and temperatures consistent with a nuclear waste disposal facility. Thermal properties of samples from laboratory-consolidated granular salt and in situ consolidated granular salt were measured using a transient plane source method at temperatures ranging from 50 to 250 °C. Additional measurements were taken on a single crystal of halite and dilated polycrystalline rock salt. Thermal conductivity of granular salt decreased with increases in temperature and porosity. Specific heat of granular salt at lower temperatures decreased with increasing porosity. At higher temperatures, porosity dependence was not apparent. The thermal conductivity and specific heat data were fit to empirical models and compared with results presented in the literature. At comparable densities, the thermal conductivities of granular salt samples consolidated hydrostatically in this study were greater than those measured previously on samples formed by quasi-static pressing. Petrographic studies of the consolidated salt indicate that the consolidation method influenced the nature of the porosity; these observations are used to explain the variation of measured thermal conductivities between the two consolidation methods. Thermal conductivity of dilated polycrystalline salt was lower than consolidated salt at comparable porosities. The pervasive crack network along grain boundaries in dilated salt impedes heat flow and results in a lower thermal conductivity compared to hydrostatically consolidated salt.

Oral Administration of Heat-Killed Mycobacterium manresensis Delays Progression toward Active Tuberculosis in C3HeB/FeJ Mice

PubMed Central

Cardona, Paula; Marzo-Escartín, Elena; Tapia, Gustavo; Díaz, Jorge; García, Vanessa; Varela, Ismael; Vilaplana, Cristina; Cardona, Pere-Joan

2016-01-01

Low-dose tolerance using heat-killed mycobacteria has been tested as a means of stopping progression toward active tuberculosis (TB) lesions in a human-like murine model using C3HeB/FeJ mice. In the present study, we studied the effect of different treatment schedules with heat-killed non-tuberculous-mycobacteria (NTM) species when given orally, based on the hypothesis of generating oral tolerance. This study included M. manresensis, a new species belonging to the fortuitum group, present in drinking water. Oral treatment with M. manresensis for 2 weeks was able to induce a PPD-specific Tregs population, which has been related to a decrease in the neutrophilic infiltration found in TB lesions. Further mechanistic analysis using PPD-stimulated splenocytes links this 2-week treatment with heat-killed M. manresensis to IL-10 production and memory PPD-specific Tregs, and also to a weak PPD-specific global immune response stimulation, increasing IL-6, TNF, and IFN-γ production. In lungs, this treatment decreased the bacillary load, granulomatous infiltration and pro-inflammatory cytokines (TNF, IFN-γ, IL-6, and IL-17). Oral administration of M. manresensis during standard treatment for TB also significantly reduced the relapse of active TB after ending the treatment. Overall the data suggest that the use of heat-killed M. manresensis could be a new and promising tool for avoiding active TB induction and as adjunctive to TB treatment. This supports the usefulness of generating a new kind of protection based on a complex balanced immune response focused on both destroying the bacilli and including control of an excessive inflammatory response. PMID:26779140

Oral Administration of Heat-Killed Mycobacterium manresensis Delays Progression toward Active Tuberculosis in C3HeB/FeJ Mice.

PubMed

Cardona, Paula; Marzo-Escartín, Elena; Tapia, Gustavo; Díaz, Jorge; García, Vanessa; Varela, Ismael; Vilaplana, Cristina; Cardona, Pere-Joan

2015-01-01

Low-dose tolerance using heat-killed mycobacteria has been tested as a means of stopping progression toward active tuberculosis (TB) lesions in a human-like murine model using C3HeB/FeJ mice. In the present study, we studied the effect of different treatment schedules with heat-killed non-tuberculous-mycobacteria (NTM) species when given orally, based on the hypothesis of generating oral tolerance. This study included M. manresensis, a new species belonging to the fortuitum group, present in drinking water. Oral treatment with M. manresensis for 2 weeks was able to induce a PPD-specific Tregs population, which has been related to a decrease in the neutrophilic infiltration found in TB lesions. Further mechanistic analysis using PPD-stimulated splenocytes links this 2-week treatment with heat-killed M. manresensis to IL-10 production and memory PPD-specific Tregs, and also to a weak PPD-specific global immune response stimulation, increasing IL-6, TNF, and IFN-γ production. In lungs, this treatment decreased the bacillary load, granulomatous infiltration and pro-inflammatory cytokines (TNF, IFN-γ, IL-6, and IL-17). Oral administration of M. manresensis during standard treatment for TB also significantly reduced the relapse of active TB after ending the treatment. Overall the data suggest that the use of heat-killed M. manresensis could be a new and promising tool for avoiding active TB induction and as adjunctive to TB treatment. This supports the usefulness of generating a new kind of protection based on a complex balanced immune response focused on both destroying the bacilli and including control of an excessive inflammatory response.

Negative specific heat with trapped ultracold quantum gases

NASA Astrophysics Data System (ADS)

Strzys, M. P.; Anglin, J. R.

2014-01-01

The second law of thermodynamics normally prescribes that heat tends to disperse, but in certain cases it instead implies that heat will spontaneously concentrate. The spontaneous formation of stars out of cold cosmic nebulae, without which the universe would be dark and dead, is an example of this phenomenon. Here we show that the counter-intuitive thermodynamics of spontaneous heat concentration can be studied experimentally with trapped quantum gases, by using optical lattice potentials to realize weakly coupled arrays of simple dynamical subsystems, so that under the standard assumptions of statistical mechanics, the behavior of the whole system can be predicted from ensemble properties of the isolated components. A naive application of the standard statistical mechanical formalism then identifies the subsystem excitations as heat in this case, but predicts them to share the peculiar property of self-gravitating protostars, of having negative micro-canonical specific heat. Numerical solution of real-time evolution equations confirms the spontaneous concentration of heat in such arrays, with initially dispersed energy condensing quickly into dense ‘droplets’. Analysis of the nonlinear dynamics in adiabatic terms allows it to be related to familiar modulational instabilities. The model thus provides an example of a dictionary mesoscopic system, in which the same non-trivial phenomenon can be understood in both thermodynamical and mechanical terms.

Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

NASA Astrophysics Data System (ADS)

Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

2016-06-01

Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

PIP-II Cryogenic System and the Evolution of Superfluid Helium Cryogenic Plant Specifications

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

Chakravarty, Anindya; Rane, Tejas; Klebaner, Arkadiy

2017-01-01

PIP-II cryogenic system: Superfluid Helium Cryogenic Plant (SHCP) and Cryogenic Distribution System (CDS) connecting the SHCP and the SC Linac (25 cryomodules) PIP-II Cryogenic System Static and dynamic heat loads for the SC Linac and static load of CDS listed out Simulation study carried out to compute SHe flow requirements for each cryomodule Comparison between the flow requirements of the cryomodules for the CW and pulsed modes of operation presented From computed heat load and pressure drop values, SHCP basic specifications evolved.

Study of polytropic exponent based on high pressure switching expansion reduction

NASA Astrophysics Data System (ADS)

Wang, Xuanyin; Luo, Yuxi; Xu, Zhipeng

2011-10-01

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

Stage and cell-specific expression and intracellular localization of the small heat shock protein Hsp27 during oogenesis and spermatogenesis in the Mediterranean fruit fly, Ceratitis capitata.

PubMed

Economou, Katerina; Kotsiliti, Elena; Mintzas, Anastassios C

2017-01-01

The cell-specific expression and intracellular distribution of the small heat protein Hsp27 was investigated in the ovaries and testes of the Mediterranean fruit fly, Ceratitis capitata (medfly), under both normal and heat shock conditions. For this study, a gfp-hsp27 strain was used to detect the chimeric protein by confocal microscopy. In unstressed ovaries, the protein was expressed throughout egg development in a stage and cell-specific pattern. In germarium, the protein was detected in the cytoplasm of the somatic cells in both unstressed and heat-shocked ovaries. In the early stages of oogenesis of unstressed ovaries, the protein was mainly located in the perinuclear region of the germ cells and in the cytoplasm of the follicle cells, while in later stages (9-10) it was distributed in the cytoplasm of the germ cells. In late stages (12-14), the protein changed localization pattern and was exclusively associated with the nuclei of the somatic cells. In heat shocked ovaries, the protein was mainly located in the nuclei of the somatic cells throughout egg chamber's development. In unstressed testes, the chimeric protein was detected in the nuclei of primary spermatocytes and in the filamentous structures of spermatid bundles, called actin cones. Interestingly, after a heat shock, the protein presented the same cell-specific localization pattern as in unstressed testes. Furthermore, the protein was also detected in the nuclei of the epithelial cells of the deferent duct, the accessory glands and the ejaculatory bulb. Our data suggest that medfly Hsp27 may have cell-specific functions, especially in the nucleus. Moreover, the association of this protein to actin cones during spermatid individualization, suggests a possible role of the protein in the formation and stabilization of actin cones. Copyright © 2016 Elsevier Ltd. All rights reserved.

7 CFR 305.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... specified temperature for a specific time period to kill targeted pests. Vapor heat. Heated air saturated with water vapor and used to raise the temperature of a commodity to a required point for a specific... products. Hot water immersion dip. Complete immersion of a commodity in heated water to raise the...

Genome-Wide Association Mapping of Fertility Reduction upon Heat Stress Reveals Developmental Stage-Specific QTLs in Arabidopsis thaliana.

PubMed

Bac-Molenaar, Johanna A; Fradin, Emilie F; Becker, Frank F M; Rienstra, Juriaan A; van der Schoot, J; Vreugdenhil, Dick; Keurentjes, Joost J B

2015-07-01

For crops that are grown for their fruits or seeds, elevated temperatures that occur during flowering and seed or fruit set have a stronger effect on yield than high temperatures during the vegetative stage. Even short-term exposure to heat can have a large impact on yield. In this study, we used Arabidopsis thaliana to study the effect of short-term heat exposure on flower and seed development. The impact of a single hot day (35°C) was determined in more than 250 natural accessions by measuring the lengths of the siliques along the main inflorescence. Two sensitive developmental stages were identified, one before anthesis, during male and female meiosis, and one after anthesis, during fertilization and early embryo development. In addition, we observed a correlation between flowering time and heat tolerance. Genome-wide association mapping revealed four quantitative trait loci (QTLs) strongly associated with the heat response. These QTLs were developmental stage specific, as different QTLs were detected before and after anthesis. For a number of QTLs, T-DNA insertion knockout lines could validate assigned candidate genes. Our findings show that the regulation of complex traits can be highly dependent on the developmental timing. © 2015 American Society of Plant Biologists. All rights reserved.

Genome-Wide Association Mapping of Fertility Reduction upon Heat Stress Reveals Developmental Stage-Specific QTLs in Arabidopsis thaliana

PubMed Central

Bac-Molenaar, Johanna A.; Fradin, Emilie F.; Becker, Frank F.M.; Rienstra, Juriaan A.; van der Schoot, J.; Vreugdenhil, Dick; Keurentjes, Joost J.B.

2015-01-01

For crops that are grown for their fruits or seeds, elevated temperatures that occur during flowering and seed or fruit set have a stronger effect on yield than high temperatures during the vegetative stage. Even short-term exposure to heat can have a large impact on yield. In this study, we used Arabidopsis thaliana to study the effect of short-term heat exposure on flower and seed development. The impact of a single hot day (35°C) was determined in more than 250 natural accessions by measuring the lengths of the siliques along the main inflorescence. Two sensitive developmental stages were identified, one before anthesis, during male and female meiosis, and one after anthesis, during fertilization and early embryo development. In addition, we observed a correlation between flowering time and heat tolerance. Genome-wide association mapping revealed four quantitative trait loci (QTLs) strongly associated with the heat response. These QTLs were developmental stage specific, as different QTLs were detected before and after anthesis. For a number of QTLs, T-DNA insertion knockout lines could validate assigned candidate genes. Our findings show that the regulation of complex traits can be highly dependent on the developmental timing. PMID:26163573

Exploring the Utility of Model-based Meteorology Data for Heat-Related Health Research and Surveillance

NASA Astrophysics Data System (ADS)

Vaidyanathan, A.; Yip, F.

2017-12-01

Context: Studies that have explored the impacts of environmental exposure on human health have mostly relied on data from weather stations, which can be limited in geographic scope. For this assessment, we: (1) evaluated the performance of the meteorological data from the North American Land Data Assimilation System Phase 2 (NLDAS) model with measurements from weather stations for public health and specifically for CDC's Environmental Public Health Tracking Program, and (2) conducted a health assessment to explore the relationship between heat exposure and mortality, and examined region-specific differences in heat-mortality (H-M) relationships when using model-based estimates in place of measurements from weather stations.Methods: Meteorological data from the NLDAS Phase 2 model was evaluated against measurements from weather stations. A time-series analysis was conducted, using both station- and model-based data, to generate H-M relationships for counties in the U.S. The county-specific risk information was pooled to characterize regional relationships for both station- and model-based data, which were then compared to identify degrees of overlap and discrepancies between results generated using the two data sources. Results: NLDAS-based heat metrics were in agreement with those generated using weather station data. In general, the H-M relationship tended to be non-linear and varied by region, particularly the heat index value at which the health risks become positively significant. However, there was a high degree of overlap between region-specific H-M relationships generated from weather stations and the NLDAS model.Interpretation: Heat metrics from NLDAS model are available for all counties in the coterminous U.S. from 1979-2015. These data can facilitate health research and surveillance activities exploring health impacts associated with long-term heat exposures at finer geographic scales.Conclusion: High spatiotemporal coverage of environmental health data is an important attribute in understanding potential public health impacts. With the limited geographic scope of station-based measurements, adopting NLDAS-based modeled estimates in CDC's Tracking Network would provide a more comprehensive understanding of specific meteorological exposures on human health.

Experimental investigation of refractory metals in the premelting region during fast heating

NASA Astrophysics Data System (ADS)

Senchenko, V. N.; Belikov, R. S.; Popov, V. S.

2015-11-01

This work demonstrates experimental possibility of investigation of high refractory materials around its melting point, particularly in premelting region with high accuracy. In this article authors describe the developed experimental setup based on rapid resistive self-heating of a sample by a large current pulse generated by a capacitor discharge circuit that allow fast pulse interruption by temperature feedback signal. The sample temperature was measured with a two-channel microsecond radiation pyrometer. Preliminary experiments were conducted on tantalum and molybdenum at heating speed of 108 K/s. The method allows investigating thermophysical properties of refractory conductive materials such as melting temperature, melting heat, specific resistivity, specific enthalpy and specific heat capacity in solid and liquid phase, especially in premelting area.

Shock-Induced Heating In A Rocket Engine

NASA Technical Reports Server (NTRS)

Lagnado, Ronald R.; Raiszadeh, Farhad

1989-01-01

Misalignments give rise to hotspots on walls. Report discusses numerical simulation of flow in and near small, ringlike cavity in wall of Space Shuttle main engine at junction of main combustion chamber and nozzle. Purpose to study effects of misalignments between combustion chamber and nozzle on transfer of heat into surfaces chamber, cavity, and nozzle. Depending on specific misalignment flow encounters forward-or backward-facing step leaving chamber and entering nozzle. Results in serious losses of performance and excessive heating of walls.

Solar energy heating system design package for a single-family residence at New Castle, Pennsylvania

NASA Technical Reports Server (NTRS)

1977-01-01

The design of a solar heating and hot water system for a single family dwelling is described. Cost trade studies on the energy conservation and architectural features of the solar house are discussed. The present status of verification for the single family heating system, i.e., proof that the components and the system meet applicable physical and functional requirements, is reported. The system integration drawings, the major subsystems drawings, and the architect's specifications and plans are included.

Signature of quantum entanglement in NH{sub 4}CuPO{sub 4}·H{sub 2}O

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

Chakraborty, Tanmoy, E-mail: tanmoy@iiserkol.ac.in; Singh, Harkirat; Mitra, Chiranjib, E-mail: chiranjib@iiserkol.ac.in

2014-01-21

Entangled solid state systems have gained a great deal of attention due to their fruitful applications in modern quantum technologies. Herein, detection of entanglement content from experimental magnetic susceptibility and specific heat data is reported for NH{sub 4}CuPO{sub 4}·H{sub 2}O in its solid state crystalline form. NH{sub 4}CuPO{sub 4}·H{sub 2}O is a prototype of Heisenberg spin 1/2 dimer system. Temperature dependent magnetic susceptibility and specific data are fitted to an isolated dimer model and the exchange coupling constant is determined. Field dependent magnetization isotherms taken at different temperatures are plotted in a three dimensional plot. Subsequently, entanglement is detected bothmore » from susceptibility and specific heat through two different entanglement measures; entanglement witness and entanglement of formation. The temperature evolution of entanglement is studied and the critical temperature is determined up to which entanglement exists. Temperature dependent nature of entanglement extracted from susceptibility and specific heat shows good consistency with each other. Moreover, the field dependent entanglement is also investigated.« less

Research supporting potential modification of the NASA specification for dry heat microbial reduction of spacecraft hardware

NASA Astrophysics Data System (ADS)

Spry, James A.; Beaudet, Robert; Schubert, Wayne

Dry heat microbial reduction (DHMR) is the primary method currently used to reduce the microbial load of spacecraft and component parts to comply with planetary protection re-quirements. However, manufacturing processes often involve heating flight hardware to high temperatures for purposes other than planetary protection DHMR. At present, the specifica-tion in NASA document NPR8020.12, describing the process lethality on B. atrophaeus (ATCC 9372) bacterial spores, does not allow for additional planetary protection bioburden reduction credit for processing outside a narrow temperature, time and humidity window. Our results from a comprehensive multi-year laboratory research effort have generated en-hanced data sets on four aspects of the current specification: time and temperature effects in combination, the effect that humidity has on spore lethality, and the lethality for spores with exceptionally high thermal resistance (so called "hardies"). This paper describes potential modifications to the specification, based on the data set gener-ated in the referenced studies. The proposed modifications are intended to broaden the scope of the current specification while still maintaining confidence in a conservative interpretation of the lethality of the DHMR process on microorganisms.

Chemical Reactions in Turbulent Mixing Flows

DTIC Science & Technology

1989-06-01

combustion to be studied over a range of pressures of 0.1 atm < po < 10atm, permitting a range of two decades of Reynolds number to be covered. Depending on ...The effects of heat release were studied in a planar, gaseous reacting mixing layer formed between two sub- sonic freestreams; one containing hydrogen...and the Reynolds number study of Mungal et al (1985). The issue of heat release effects on the flow was specifically addressed elsewhere (see

Theoretical analysis for the specific heat and thermal parameters of solid C60

NASA Astrophysics Data System (ADS)

Soto, J. R.; Calles, A.; Castro, J. J.

1997-08-01

We present the results of a theoretical analysis for the thermal parameters and phonon contribution to the specific heat in solid C60. The phonon contribution to the specific heat is calculated through the solution of the corresponding dynamical matrix, for different points in the Brillouin zone, and the construccion of the partial and generalized phonon density of states. The force constants are obtained from a first principle calculation, using a SCF Hartree-Fock wave function from the Gaussian 92 program. The thermal parameters reported are the effective temperatures and vibrational amplitudes as a function of temperature. Using this model we present a parametization scheme in order to reproduce the general behaviour of the experimental specific heat for these materials.

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

PubMed Central

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

2013-01-01

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

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

PubMed

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

2011-03-01

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

Heat and mortality for ischemic and hemorrhagic stroke in 12 cities of Jiangsu Province, China.

PubMed

Zhou, Lian; Chen, Kai; Chen, Xiaodong; Jing, Yuanshu; Ma, Zongwei; Bi, Jun; Kinney, Patrick L

2017-12-01

Little evidence exists on the relationship between heat and subtypes of stroke mortality, especially in China. Moreover, few studies have reported the effect modification by individual characteristics on heat-related stroke mortality. In this study, we aimed to evaluate the effect of heat exposure on total, ischemic, and hemorrhagic stroke mortality and its individual modifiers in 12 cities in Jiangsu Province, China during 2009 to 2013. We first used a distributed lag non-linear model with quasi-Poisson regression to examine the city-specific heat-related total, ischemic, and hemorrhagic stroke mortality risks at 99th percentile vs. 75th percentile of daily mean temperature in the whole year for each city, while adjusting for long-term trend, season, relative humidity, and day of the week. Then, we used a random-effects meta-analysis to pool the city-specific risk estimates. We also considered confounding by air pollution and effect modification by gender, age, education level, and death location. Overall, the heat-related mortality risk in 12 Jiangsu cities was 1.54 (95%CI: 1.44 to 1.65) for total stroke, 1.63 (95%CI: 1.48 to 1.80) for ischemic stroke, and 1.36 (95%CI: 1.26 to 1.48) for hemorrhagic stroke, respectively. Estimated total, ischemic, and hemorrhagic stroke mortality risks were higher for women versus men, older people versus younger people, those with low education levels versus high education levels, and deaths that occurred outside of hospital. Air pollutants did not significantly influence the heat-related stroke mortality risk. Heat exposure significantly increased both ischemic and hemorrhagic stroke mortality risks in Jiangsu Province, China. Females, the elderly, and those with low education levels are particularly vulnerable to this effect. Copyright © 2017 Elsevier B.V. All rights reserved.

TRPV1 unlike TRPV2 is restricted to a subset of mechanically insensitive cutaneous nociceptors responding to heat.

PubMed

Lawson, Jeffrey J; McIlwrath, Sabrina L; Woodbury, C Jeffery; Davis, Brian M; Koerber, H Richard

2008-04-01

In the present study, a murine ex vivo somatosensory system preparation was used to determine the response characteristics of cutaneous sensory neurons staining positively for TRPV1 or TRPV2. TRPV1 immunostaining was found exclusively (11/11) in a specific set of mechanically insensitive unmyelinated (C) nociceptors that responded to heating of their receptive fields. No cutaneous C-fibers that responded to both mechanical and heat stimuli stained positively for TRPV1 (0/62). The relationship between TRPV2 and heat transduction characteristics was not as clear, as few unmyelinated or myelinated fibers that responded to heat contained TRPV2. TRPV2 was found most frequently in mechanically sensitive myelinated fibers, including both low threshold and high threshold mechanoreceptors (nociceptors). Although TRPV2 was found in only 1 of 6 myelinated polymodal nociceptors, it was found in a majority (10/16) of myelinated mechanical nociceptors. Thus, whereas the in vivo role of TRPV1 as a heat-sensitive channel in cutaneous sensory neurons is clearly defined, the role of TRPV2 in cutaneous neurons remains unknown. These results also suggest that TRPV1 may be essential for heat transduction in a specific subset of mechanically insensitive cutaneous nociceptors and that this subset may constitute a discrete heat input pathway for inflammation-induced thermal pain. The distinct subset of murine cutaneous nociceptors containing TRPV1 has many attributes in common with mechanically insensitive C-fibers in humans that are believed to play a role in pathological pain states. Therefore, these murine fibers provide a clinically relevant animal model for further study of this group of cutaneous nociceptors.

New iron-oxide particles for magnetic nanoparticle hyperthermia: an in-vitro and in-vivo pilot study

NASA Astrophysics Data System (ADS)

Hedayati, Mohammad; Attaluri, Anilchandra; Bordelon, David; Goh, R.; Armour, Michael; Zhou, Haoming; Cornejo, Christine; Wabler, Michele; Zhang, Yonggang; DeWeese, Theodore; Ivkov, Robert

2013-02-01

Magnetic nanoparticle hyperthermia (mNHP) is regarded as a promising minimally invasive procedure. These nanoparticles generate heat when exposed to alternating magnetic fields (AMFs) and thus have shown a potential for selective delivery of heat to a target such as a cancer cell. Despite the great promise however, successful clinical translation has been limited in part by technical challenges of selectively delivering heat only to the target tissue. Interaction of AMF with tissues also deposits heat through Joule heating via eddy currents. Considerations of patient safety thus constrain the choice of AMF power and frequency to values that are insufficient to produce desirable heating from available nanoparticle formulations. Therefore, considerable effort must be directed to the design of particles and the AMF device to maximize the specific delivery of heat to the intended target while minimizing the unintended and non-specific heating. We have recently developed new iron-oxide nanoparticles (IONPs) having much higher heating capability at the clinically relevant amplitudes and frequencies than other formulations. Here, we utilize a new rectangular coil designed for treating multi well tissue culture plate and show that these particles are superior to two commercially available IONPs for hyperthermia of DU145 prostate cancer cells in culture. We report results of pilot in-vivo experiments using the DU145 human prostate xenograft model in nude male mouse. AMF treatment yielded an intratumor temperature rise > 10 °C in <10 min heating (AMF amplitude 29 kA/m @160 kHz) with ~4 mg nanoparticle /g tumor while maintaining rectal (core) temperature well within physiological range.

Sun Safety at Work Canada: a multiple case-study protocol to develop sun safety and heat protection programs and policies for outdoor workers.

PubMed

Kramer, Desre M; Tenkate, Thomas; Strahlendorf, Peter; Kushner, Rivka; Gardner, Audrey; Holness, D Linn

2015-07-10

CAREX Canada has identified solar ultraviolet radiation (UV) as the second most prominent carcinogenic exposure in Canada, and over 75 % of Canadian outdoor workers fall within the highest exposure category. Heat stress also presents an important public health issue, particularly for outdoor workers. The most serious form of heat stress is heat stroke, which can cause irreversible damage to the heart, lungs, kidneys, and liver. Although the need for sun and heat protection has been identified, there is no Canada-wide heat and sun safety program for outdoor workers. Further, no prevention programs have addressed both skin cancer prevention and heat stress in an integrated approach. The aim of this partnered study is to evaluate whether a multi-implementation, multi-evaluation approach can help develop sustainable workplace-specific programs, policies, and procedures to increase the use of UV safety and heat protection. This 2-year study is a theory-driven, multi-site, non-randomized study design with a cross-case analysis of 13 workplaces across four provinces in Canada. The first phase of the study includes the development of workplace-specific programs with the support of the intensive engagement of knowledge brokers. There will be a three-points-in-time evaluation with process and impact components involving the occupational health and safety (OHS) director, management, and workers with the goal of measuring changes in workplace policies, procedures, and practices. It will use mixed methods involving semi-structured key informant interviews, focus groups, surveys, site observations, and UV dosimetry assessment. Using the findings from phase I, in phase 2, a web-based, interactive, intervention planning tool for workplaces will be developed, as will the intensive engagement of intermediaries such as industry decision-makers to link to policymakers about the importance of heat and sun safety for outdoor workers. Solar UV and heat are both health and safety hazards. Using an occupational health and safety risk assessment and control framework, Sun Safety at Work Canada will support workplaces to assess their exposure risks, implement control strategies that build on their existing programs, and embed the controls into their existing occupational health and safety system.

Mathematical modeling and analysis of heat pipe start-up from the frozen state

NASA Technical Reports Server (NTRS)

Jang, Jong Hoon; Faghri, Amir; Chang, Won Soon; Mahefkey, Edward T.

1989-01-01

The start-up process of a frozen heat pipe is described and a complete mathematical model for the start-up of the frozen heat pipe is developed based on the existing experimental data, which is simplified and solved numerically. The two-dimensional transient model for the wall and wick is coupled with the one-dimensional transient model for the vapor flow when vaporization and condensation occur at the interface. A parametric study is performed to examine the effect of the boundary specification at the surface of the outer wall on the successful start-up from the frozen state. For successful start-up, the boundary specification at the outer wall surface must melt the working substance in the condenser before dry-out takes place in the evaporator.

Mathematical modeling and analysis of heat pipe start-up from the frozen state

NASA Technical Reports Server (NTRS)

Jang, J. H.; Faghri, A.; Chang, W. S.; Mahefkey, E. T.

1990-01-01

The start-up process of a frozen heat pipe is described and a complete mathematical model for the start-up of the frozen heat pipe is developed based on the existing experimental data, which is simplified and solved numerically. The two-dimensional transient model for the wall and wick is coupled with the one-dimensional transient model for the vapor flow when vaporization and condensation occur at the interface. A parametric study is performed to examine the effect of the boundary specification at the surface of the outer wall on the successful start-up from the frozen state. For successful start-up, the boundary specification at the outer wall surface must melt the working substance in the condenser before dry-out takes place in the evaporator.

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 short-term effect of heat waves on mortality and its modifiers in China: an analysis from 66 communities.

PubMed

Ma, Wenjun; Zeng, Weilin; Zhou, Maigeng; Wang, Lijun; Rutherford, Shannon; Lin, Hualiang; Liu, Tao; Zhang, Yonghui; Xiao, Jianpeng; Zhang, Yewu; Wang, Xiaofeng; Gu, Xin; Chu, Cordia

2015-02-01

Many studies have reported increased mortality risk associated with heat waves. However, few have assessed the health impacts at a nation scale in a developing country. This study examines the mortality effects of heat waves in China and explores whether the effects are modified by individual-level and community-level characteristics. Daily mortality and meteorological variables from 66 Chinese communities were collected for the period 2006-2011. Heat waves were defined as ≥2 consecutive days with mean temperature ≥95th percentile of the year-round community-specific distribution. The community-specific mortality effects of heat waves were first estimated using a Distributed Lag Non-linear Model (DLNM), adjusting for potential confounders. To investigate effect modification by individual characteristics (age, gender, cause of death, education level or place of death), separate DLNM models were further fitted. Potential effect modification by community characteristics was examined using a meta-regression analysis. A total of 5.0% (95% confidence intervals (CI): 2.9%-7.2%) excess deaths were associated with heat waves in 66 Chinese communities, with the highest excess deaths in north China (6.0%, 95% CI: 1%-11.3%), followed by east China (5.2%, 95% CI: 0.4%-10.2%) and south China (4.5%, 95% CI: 1.4%-7.6%). Our results indicate that individual characteristics significantly modified heat waves effects in China, with greater effects on cardiovascular mortality, cerebrovascular mortality, respiratory mortality, the elderly, females, the population dying outside of a hospital and those with a higher education attainment. Heat wave mortality effects were also more pronounced for those living in urban cities or densely populated communities. Heat waves significantly increased mortality risk in China with apparent spatial heterogeneity, which was modified by some individual-level and community-level factors. Our findings suggest adaptation plans that target vulnerable populations in susceptible communities during heat wave events should be developed to reduce health risks. Copyright © 2014 Elsevier Ltd. All rights reserved.

Scramjet Isolator Modeling and Control

DTIC Science & Technology

2011-12-01

12 γ Ratio of specific heats . . . . . . . . . . . . . . . . . . . . 12 p1 Static pressure entering shock . . . . . . . . . . . . . . . . 12 M1 Mach...138 MAve Average stream Mach number . . . . . . . . . . . . . . . . 138 γ Ratio of specific heats ... heats , p1 is the static pressure entering the shock, and M1 is the Mach number of the flow entering the shock. Subsequent researchers [9] took a

Lattice specific heat for the RMIn5 (R=Gd, La, Y; M=Co, Rh) compounds: Non-magnetic contribution subtraction

NASA Astrophysics Data System (ADS)

Facio, Jorge I.; Betancourth, D.; Cejas Bolecek, N. R.; Jorge, G. A.; Pedrazzini, Pablo; Correa, V. F.; Cornaglia, Pablo S.; Vildosola, V.; García, D. J.

2016-06-01

We analyze theoretically a common experimental process used to obtain the magnetic contribution to the specific heat of a given magnetic material. In the procedure, the specific heat of a non-magnetic analog is measured and used to subtract the non-magnetic contributions, which are generally dominated by the lattice degrees of freedom in a wide range of temperatures. We calculate the lattice contribution to the specific heat for the magnetic compounds GdMIn5 (M=Co, Rh) and for the non-magnetic YMIn5 and LaMIn5 (M=Co, Rh), using density functional theory based methods. We find that the best non-magnetic analog for the subtraction depends on the magnetic material and on the range of temperatures. While the phonon specific heat contribution of YRhIn5 is an excellent approximation to the one of GdCoIn5 in the full temperature range, for GdRhIn5 we find a better agreement with LaCoIn5, in both cases, as a result of an optimum compensation effect between masses and volumes. We present measurements of the specific heat of the compounds GdMIn5 (M=Co, Rh) up to room temperature where it surpasses the value expected from the Dulong-Petit law. We obtain a good agreement between theory and experiment when we include anharmonic effects in the calculations.

Complete Mie-Gruneisen Equation of State

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

Menikoff, Ralph

2012-06-28

The Mie-Gruneisen equation of state (EOS) is frequently used in hydro simulations to model solids at high pressure (up to a few Mb). It is an incomplete EOS characterized by a Gruneisen coefficient, {Lambda} = -V({partial_derivative}{sub e}P){sub V}, that is a function of only V. Expressions are derived for isentropes and isotherms. This enables the extension to a complete EOS. Thermodynamic consistency requires that the specific heat is a function of a single scaled temperature. A complete extension is uniquely determined by the temperature dependence of the specific heat at a fixed reference density. In addition we show that ifmore » the domain of the EOS extends to T = 0 and the specific heat vanishes on the zero isotherm then {Lambda} a function of only V is equivalent to a specific heat with a single temperature scale. If the EOS domain does not include the zero isotherm, then a specific heat with a single temperature scale leads to a generalization of the Mie-Gruneisen EOS in which the pressure is linear in both the specific energy and the temperature. Such an EOS has previously been used to model liquid nitromethane.« less

An International Round-Robin Study, Part II: Thermal Diffusivity, Specific Heat and Thermal Conductivity

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

Wang, Hsin; Porter, Wallace D; Bottner, Harold

2013-01-01

For bulk thermoelectrics, figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In recent years, the most significant improvements in ZT were mainly due to successful reduction of thermal conductivity. However, thermal conductivity cannot be measured directly at high temperatures. The combined measurements of thermal diffusivity and specific heat and density are required. It has been shown that thermal conductivity is the property with the greatest uncertainty and has a direct influence on the accuracy of the figure of merit. The International Energy Agency (IEA)more » group under the implementing agreement for Advanced Materials for Transportation (AMT) has conducted two international round-robins since 2009. This paper is Part II of the international round-robin testing of transport properties of bulk bismuth telluride. The main focuses in Part II are on thermal diffusivity, specific heat and thermal conductivity.« less

Low-temperature magnetic properties of GdCoIn5

NASA Astrophysics Data System (ADS)

Betancourth, D.; Facio, J. I.; Pedrazzini, P.; Jesus, C. B. R.; Pagliuso, P. G.; Vildosola, V.; Cornaglia, Pablo S.; García, D. J.; Correa, V. F.

2015-01-01

A comprehensive experimental and theoretical study of the low temperature properties of GdCoIn5 was performed. Specific heat, thermal expansion, magnetization and electrical resistivity were measured in good quality single crystals down to 4He temperatures. All the experiments show a second-order-like phase transition at 30 K probably associated with the onset of antiferromagnetic order. The magnetic susceptibility shows a pronounced anisotropy below TN with an easy magnetic axis perpendicular to the crystallographic ĉ-axis. Total energy GGA+U calculations indicate a ground state with magnetic moments localized at the Gd ions and allowed a determination of the Gd-Gd magnetic interactions. Band structure calculations of the electron and phonon contributions to the specific heat together with Quantum Monte Carlo calculations of the magnetic contributions show a very good agreement with the experimental data. Comparison between experiment and calculations suggests a significant anharmonic contribution to the specific heat at high temperature (T ≳ 100 K).

Air-Cooled Heat Exchanger for High-Temperature Power Electronics: Preprint

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

Waye, S. K.; Lustbader, J.; Musselman, M.

2015-05-06

This work demonstrates a direct air-cooled heat exchanger strategy for high-temperature power electronic devices with an application specific to automotive traction drive inverters. We present experimental heat dissipation and system pressure curves versus flow rate for baseline and optimized sub-module assemblies containing two ceramic resistance heaters that provide device heat fluxes. The maximum allowable junction temperature was set to 175 deg.C. Results were extrapolated to the inverter scale and combined with balance-of-inverter components to estimate inverter power density and specific power. The results exceeded the goal of 12 kW/L and 12 kW/kg for power density and specific power, respectively.

On the Occurrence of Thermal Nonequilibrium in Coronal Loops

NASA Astrophysics Data System (ADS)

Froment, C.; Auchère, F.; Mikić, Z.; Aulanier, G.; Bocchialini, K.; Buchlin, E.; Solomon, J.; Soubrié, E.

2018-03-01

Long-period EUV pulsations, recently discovered to be common in active regions, are understood to be the coronal manifestation of thermal nonequilibrium (TNE). The active regions previously studied with EIT/Solar and Heliospheric Observatory and AIA/SDO indicated that long-period intensity pulsations are localized in only one or two loop bundles. The basic idea of this study is to understand why. For this purpose, we tested the response of different loop systems, using different magnetic configurations, to different stratifications and strengths of the heating. We present an extensive parameter-space study using 1D hydrodynamic simulations (1020 in total) and conclude that the occurrence of TNE requires specific combinations of parameters. Our study shows that the TNE cycles are confined to specific ranges in parameter space. This naturally explains why only some loops undergo constant periodic pulsations over several days: since the loop geometry and the heating properties generally vary from one loop to another in an active region, only the ones in which these parameters are compatible exhibit TNE cycles. Furthermore, these parameters (heating and geometry) are likely to vary significantly over the duration of a cycle, which potentially limits the possibilities of periodic behavior. This study also confirms that long-period intensity pulsations and coronal rain are two aspects of the same phenomenon: both phenomena can occur for similar heating conditions and can appear simultaneously in the simulations.

Properties and heat transfer coefficients of four molten-salt high temperature heat transfer fluid candidates for concentrating solar power plants

NASA Astrophysics Data System (ADS)

Liu, T. L.; Liu, W. R.; Xu, X. H.

2017-11-01

Heat transfer fluid is one critical component for transferring and storing heat energy in concentrating solar power systems. Molten-salt mixtures can be used as high temperature heat transfer fluids because of their thermophysical properties. This paper studied the thermophysical properties of Li2CO3-Na2CO3-K2CO3 eutectic salt and three eutectic chloride salts NaCl-KCl-ZnCl2 with different compositions in the range of 450-600°C and 250-800°C, respectively. Properties including specific heat capacity, thermal conductivity, density and viscosity were determined based on imperial correlations and compared at different operating temperatures. The heat transfer coefficients of using different eutectic salts as heat transfer fluids were also calculated and compared in their operating temperature range. It is concluded that all the four eutectic salts can satisfy the requirements of a high-temperature heat transfer fluid.

The social impacts of the heat-health watch/warning system in Phoenix, Arizona: assessing the perceived risk and response of the public.

PubMed

Kalkstein, Adam J; Sheridan, Scott C

2007-10-01

Heat is the leading weather-related killer in the United States. Although previous research suggests that social influences affect human responses to natural disaster warnings, no studies have examined the social impacts of heat or heat warnings on a population. Here, 201 surveys were distributed in Metropolitan Phoenix to determine the social impacts of the heat warning system, or more specifically, to gauge risk perception and warning response. Consistent with previous research, increased risk perception of heat results in increased response to a warning. Different social factors such as sex, race, age, and income all play an important role in determining whether or not people will respond to a warning. In particular, there is a strong sense of perceived risk to the heat among Hispanics which translates to increased response when heat warnings are issued. Based on these findings, suggestions are presented to help improve the Phoenix Heat Warning System.

Measuring the Heats of Water.

ERIC Educational Resources Information Center

Hunt, James L.; Tegart, Tracy L.

1994-01-01

Uses common equipment (tea kettle and vacuum bottles) to precisely measure the specific heat, latent heat of fusion, and latent heat of vaporization of water. Provides descriptions for all three experiments. (MVL)

Heat addition to a subsonic boundary layer: A preliminary analytical study

NASA Technical Reports Server (NTRS)

Macha, J. M.; Norton, D. J.

1971-01-01

A preliminary analytical study of the effects of heat addition to the subsonic boundary layer flow over a typical airfoil shape is presented. This phenomenon becomes of interest in the space shuttle mission since heat absorbed by the wing structure during re-entry will be rejected to the boundary layer during the subsequent low speed maneuvering and landing phase. A survey of existing literature and analytical solutions for both laminar and turbulent flow indicate that a heated surface generally destabilizes the boundary layer. Specifically, the boundary layer thickness is increased, the skin friction at the surface is decreased and the point of flow separation is moved forward. In addition, limited analytical results predict that the angle of attack at which a heated airfoil will stall is significantly less than the stall angle of an unheated wing. These effects could adversely affect the lift and drag, and thus the maneuvering capabilities of booster and orbiter shuttle vehicles.

High-field specific heats of A15 V3Si and Nb3Sn

NASA Astrophysics Data System (ADS)

Stewart, G. R.; Brandt, B. L.

1984-04-01

In order to further understand the anomalous behavior of the specific heat of Nb3Sn in an 18-T magnetic field discovered by Stewart, Cort, and Webb

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

PubMed

Bousfiha, Amal; Lotfi, Aarab

2013-08-28

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

Development of a semitransparent ceramic heat-insulation for an eco-friendly combustion chamber of Low-Heat-Rejection diesel

NASA Astrophysics Data System (ADS)

Merzlikin, V. G.; Gutierrez, M. O.; Makarov, A. R.; Bekaev, A. A.; Bystrov, A. V.; Zagumennov, F. A.

2018-02-01

Efficiency of diesel has been studied using well-known types of the ceramic heat-insulating HICs- or thermal barrier TBCs-coatings. This problem is relevant for a high-speed diesel combustion chamber in which intensive radiant component (near IR) reaches ~50% within total thermal flux. Therefore, in their papers the authors offered new concept of study these materials as semitransparent SHICs-, STBCs-coatings. On the Mie scattering theory the effect of selection of the specific structural composition and porosity of coatings on the variation of their optical parameters is considered. Conducted spectrophotometric modeling of the volume-absorbed radiant energy by the coating had determined their acceptable temperature field. For rig testings coated piston using selected SHIC (PSZ-ceramic ZrO2+8%Y2O3) with a calculated optimum temperature gradient was chosen. A single cylinder experimental tractor diesel was used. At rotation frequency n > 2800 rpm the heat losses were no more than 0.2 MW/m2. Executed testings showed ~2-3% lower specific fuel consumption in contrast the diesel with uncoated piston. Effective power and drive torque were ~2-5% greater. The authors have substantiated the growth the efficiency of this Low-Heat-Rejection (LHR) diesel due to the known effect of soot deposition gasification at high speed.Then unpolluted semitransparent ceramic thermal insulation forms the required thermoradiation fields and temperature profiles and can affect regulation of heat losses and reduction of primarily nitrogen dioxide generation.

Semitransparent ceramic heat-insulation of eco-friendly Low- Heat-Rejection diesel

NASA Astrophysics Data System (ADS)

Merzlikin, V. G.; Gutierrez, M. O.; Makarov, A. R.; Kostukov, A. V.; Dementev, A. A.; Khudyakov, S. V.; Zagumennov, F. A.

2018-03-01

Efficiency of diesel has been studied using well-known types of the ceramic heat-insulating HICs- or thermal barrier TBCs-coatings. This problem is relevant for a high-speed diesel combustion chamber in which an intensive radiant component (near IR) reaches ~50% within total thermal flux. Therefore, in their works the authors had been offering new concept of study these materials as semitransparent SHICs-, STBCs-coatings. On the Mie scattering theory, the effect of selection of the specific structural composition and porosity of coatings on the variation of their optical parameters is considered. Conducted spectrophotometric modeling of the volume-absorbed radiant energy by the coating had determined their acceptable temperature field. For rig testings, a coated piston using selected SHIC (PSZ-ceramic ZrO2+8%Y2O3) with a calculated optimum temperature gradient was chosen. A single cylinder experimental tractor diesel was used. At rotation frequency n > 2800 rpm, the heat losses were no more than 0.2 MW/m2. Executed testings showed ~2-3% lower specific fuel consumption in contrast to the diesel with an uncoated piston. Effective power and drive torque were ∼2-5% greater. The authors have substantiated the growth the efficiency of this Low-Heat-Rejection(LHR) diesel due to the known effect of soot deposition gasification at high speed. Then unpolluted semitransparent ceramic thermal insulation forms the required thermoradiation fields and temperature profiles and can affect regulation of heat losses and a reduction of primarily nitrogen dioxide generation.

Experimental Study of Heat Transfer Performance of Polysilicon Slurry Drying Process

NASA Astrophysics Data System (ADS)

Wang, Xiaojing; Ma, Dongyun; Liu, Yaqian; Wang, Zhimin; Yan, Yangyang; Li, Yuankui

2016-12-01

In recent years, the growth of the solar energy photovoltaic industry has greatly promoted the development of polysilicon. However, there has been little research into the slurry by-products of polysilicon production. In this paper the thermal performance of polysilicon slurry was studied in an industrial drying process with a twin-screw horizontal intermittent dryer. By dividing the drying process into several subunits, the parameters of each unit could be regarded as constant in that period. The time-dependent changes in parameters including temperature, specific heat and evaporation enthalpy were plotted. An equation for the change in the heat transfer coefficient over time was calculated based on heat transfer equations. The concept of a distribution coefficient was introduced to reflect the influence of stirring on the heat transfer area. The distribution coefficient ranged from 1.2 to 1.7 and was obtained with the fluid simulation software FLUENT, which simplified the calculation of heat transfer area during the drying process. These experimental data can be used to guide the study of polysilicon slurry drying and optimize the design of dryers for industrial processes.

Land use planning and surface heat island formation: A parcel-based radiation flux approach

NASA Astrophysics Data System (ADS)

Stone, Brian; Norman, John M.

This article presents a study of residential parcel design and surface heat island formation in a major metropolitan region of the southeastern United States. Through the integration of high-resolution multispectral data (10 m) with property tax records for over 100,000 single-family residential parcels in the Atlanta, Georgia, metropolitan region, the influence of the size and material composition of residential land use on an indicator of surface heat island formation is reported. In contrast to previous work on the urban heat island, this study derives a parcel-based indicator of surface warming to permit the impact of land use planning regulations governing the density and design of development on the excess surface flux of heat energy to be measured. The results of this study suggest that the contribution of individual land parcels to regional surface heat island formation could be reduced by approximately 40% through the adoption of specific land use planning policies, such as zoning and subdivision regulations, and with no modifications to the size or albedo of the residential structure.

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications.

PubMed

Lasfargues, Mathieu; Bell, Andrew; Ding, Yulong

In this study, TiO 2 nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO 4 ) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

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.

Divergence of turbulent fluxes in the surface layer: case of a coastal city

NASA Astrophysics Data System (ADS)

Pigeon, G.; Lemonsu, A.; Grimmond, C. S. B.; Durand, P.; Thouron, O.; Masson, V.

2007-08-01

This study quantifies the processes that take place in the layer between the mean building height and the measurement level of an energy balance micrometeorological tower located in the dense old core of a coastal European city. The contributions of storage, vertical advection, horizontal advection and radiative divergence for heat are evaluated with the available measurements and with a three-dimensional, high-resolution meteorological simulation that had been evaluated against observations. The study focused on a summer period characterized by sea-breeze flows that affect the city. In this specific configuration, it appears that the horizontal advection is the dominant term. During the afternoon when the sea breeze is well established, correction of the sensible heat flux with horizontal heat advection increases the measured sensible heat flux up to 100 W m-2. For latent heat flux, the horizontal moisture advection converted to equivalent latent heat flux suggests a decrease of 50 W m-2. The simulation reproduces well the temporal evolution and magnitude of these terms.

Heat-related mortality projections for cardiovascular and respiratory disease under the changing climate in Beijing, China.

PubMed

Li, Tiantian; Ban, Jie; Horton, Radley M; Bader, Daniel A; Huang, Ganlin; Sun, Qinghua; Kinney, Patrick L

2015-08-06

Because heat-related health effects tend to become more serious at higher temperatures, there is an urgent need to determine the mortality projection of specific heat-sensitive diseases to provide more detailed information regarding the variation of the sensitivity of such diseases. In this study, the specific mortality of cardiovascular and respiratory disease in Beijing was initially projected under five different global-scale General Circulation Models (GCMs) and two Representative Concentration Pathways scenarios (RCPs) in the 2020s, 2050s, and 2080s compared to the 1980s. Multi-model ensembles indicated cardiovascular mortality could increase by an average percentage of 18.4%, 47.8%, and 69.0% in the 2020s, 2050s, and 2080s under RCP 4.5, respectively, and by 16.6%,73.8% and 134% in different decades respectively, under RCP 8.5 compared to the baseline range. The same increasing pattern was also observed in respiratory mortality. The heat-related deaths under the RCP8.5 scenario were found to reach a higher number and to increase more rapidly during the 21(st) century compared to the RCP4.5 scenario, especially in the 2050s and the 2080s. The projection results show potential trends in cause-specific mortality in the context of climate change, and provide support for public health interventions tailored to specific climate-related future health risks.

Heat-related mortality projections for cardiovascular and respiratory disease under the changing climate in Beijing, China

NASA Astrophysics Data System (ADS)

Li, Tiantian; Ban, Jie; Horton, Radley M.; Bader, Daniel A.; Huang, Ganlin; Sun, Qinghua; Kinney, Patrick L.

2015-08-01

Because heat-related health effects tend to become more serious at higher temperatures, there is an urgent need to determine the mortality projection of specific heat-sensitive diseases to provide more detailed information regarding the variation of the sensitivity of such diseases. In this study, the specific mortality of cardiovascular and respiratory disease in Beijing was initially projected under five different global-scale General Circulation Models (GCMs) and two Representative Concentration Pathways scenarios (RCPs) in the 2020s, 2050s, and 2080s compared to the 1980s. Multi-model ensembles indicated cardiovascular mortality could increase by an average percentage of 18.4%, 47.8%, and 69.0% in the 2020s, 2050s, and 2080s under RCP 4.5, respectively, and by 16.6%,73.8% and 134% in different decades respectively, under RCP 8.5 compared to the baseline range. The same increasing pattern was also observed in respiratory mortality. The heat-related deaths under the RCP8.5 scenario were found to reach a higher number and to increase more rapidly during the 21st century compared to the RCP4.5 scenario, especially in the 2050s and the 2080s. The projection results show potential trends in cause-specific mortality in the context of climate change, and provide support for public health interventions tailored to specific climate-related future health risks.

Heat-related mortality projections for cardiovascular and respiratory disease under the changing climate in Beijing, China

PubMed Central

Li, Tiantian; Ban, Jie; Horton, Radley M.; Bader, Daniel A.; Huang, Ganlin; Sun, Qinghua; Kinney, Patrick L.

2015-01-01

Because heat-related health effects tend to become more serious at higher temperatures, there is an urgent need to determine the mortality projection of specific heat-sensitive diseases to provide more detailed information regarding the variation of the sensitivity of such diseases. In this study, the specific mortality of cardiovascular and respiratory disease in Beijing was initially projected under five different global-scale General Circulation Models (GCMs) and two Representative Concentration Pathways scenarios (RCPs) in the 2020s, 2050s, and 2080s compared to the 1980s. Multi-model ensembles indicated cardiovascular mortality could increase by an average percentage of 18.4%, 47.8%, and 69.0% in the 2020s, 2050s, and 2080s under RCP 4.5, respectively, and by 16.6%,73.8% and 134% in different decades respectively, under RCP 8.5 compared to the baseline range. The same increasing pattern was also observed in respiratory mortality. The heat-related deaths under the RCP8.5 scenario were found to reach a higher number and to increase more rapidly during the 21st century compared to the RCP4.5 scenario, especially in the 2050s and the 2080s. The projection results show potential trends in cause-specific mortality in the context of climate change, and provide support for public health interventions tailored to specific climate-related future health risks. PMID:26247438

Laser Doppler assessment of dermal circulatory changes in people with coronary artery disease.

PubMed

Agarwal, Sharad C; Allen, John; Murray, Alan; Purcell, Ian F

2012-07-01

Dermal microcirculation provides an easily accessible vasculature bed which can be used to assess endothelial mediated vasodilatation. We studied and compared microcirculatory changes in response to acetylcholine iontophoresis (ACh), local heating of the skin and reactive hyperaemia in patients with coronary artery disease (CAD). Forty eight patients with CAD were studied and compared with 25 age and sex matched control subjects. Vasodilatory changes in the dermal microcirculation were assessed in response to ACh iontophoresis, local heating of the skin and reactive hyperaemia using a laser Doppler flowmeter (LDF). Body mass index (BMI) and systolic BP were higher in people with CAD, (p=0.001, 0.043). The perfusion change (measured as absolute in agreement with our previous publish results) in response to ACh iontophoresis, local heating of the skin and reactive hyperaemia, in healthy controls was 234 (190-286), 90 (69-118), 139(106-172) arbitrary perfusion units (APU) compared to 161 (121-214), 50 (39-63), 116(77-143) APU in patients with CAD; p<0.03. The time to peak perfusion in response to reactive hyperaemia was significantly higher in patients with CAD, 14.1±4.0 vs 10.9±1.7s; p=0.001. There was a small but significant positive correlation between the perfusion change in response to ACh iontophoresis and local heating (r=0.31, p=0.035). On ROC curve analysis, perfusion changes with heating had higher sensitivity and specificity in discriminating patients with CAD from the healthy controls with an area under the curve (AUC) of 0.86, with a specificity of 92% and sensitivity of 77% compared to a perfusion changes by reactive hyperaemia, AUC of 0.68 (41% sensitivity and 91% specificity) and ACh iontophoresis, AUC of 0.76 (88% sensitivity and 60% specificity). Vasodilatation in the dermal microcirculation measured by the three techniques is attenuated in patients with coronary artery disease. Local heating of the skin is a better discriminator of patients with CAD than ACh iontophoresis and reactive hyperaemia. Copyright © 2012 Elsevier Inc. All rights reserved.

Evaluation and Application of Satellite-Based Latent Heating Profile Estimation Methods

NASA Technical Reports Server (NTRS)

Olson, William S.; Grecu, Mircea; Yang, Song; Tao, Wei-Kuo

2004-01-01

In recent years, methods for estimating atmospheric latent heating vertical structure from both passive and active microwave remote sensing have matured to the point where quantitative evaluation of these methods is the next logical step. Two approaches for heating algorithm evaluation are proposed: First, application of heating algorithms to synthetic data, based upon cloud-resolving model simulations, can be used to test the internal consistency of heating estimates in the absence of systematic errors in physical assumptions. Second, comparisons of satellite-retrieved vertical heating structures to independent ground-based estimates, such as rawinsonde-derived analyses of heating, provide an additional test. The two approaches are complementary, since systematic errors in heating indicated by the second approach may be confirmed by the first. A passive microwave and combined passive/active microwave heating retrieval algorithm are evaluated using the described approaches. In general, the passive microwave algorithm heating profile estimates are subject to biases due to the limited vertical heating structure information contained in the passive microwave observations. These biases may be partly overcome by including more environment-specific a priori information into the algorithm s database of candidate solution profiles. The combined passive/active microwave algorithm utilizes the much higher-resolution vertical structure information provided by spaceborne radar data to produce less biased estimates; however, the global spatio-temporal sampling by spaceborne radar is limited. In the present study, the passive/active microwave algorithm is used to construct a more physically-consistent and environment-specific set of candidate solution profiles for the passive microwave algorithm and to help evaluate errors in the passive algorithm s heating estimates. Although satellite estimates of latent heating are based upon instantaneous, footprint- scale data, suppression of random errors requires averaging to at least half-degree resolution. Analysis of mesoscale and larger space-time scale phenomena based upon passive and passive/active microwave heating estimates from TRMM, SSMI, and AMSR data will be presented at the conference.

Exploring Heat Stress Relief Measures among the Australian Labour Force

PubMed Central

Zander, Kerstin K.; Mathew, Supriya; Garnett, Stephen T.

2018-01-01

Australia experiences frequent heat waves and generally high average temperatures throughout the continent with substantial impacts on human health and the economy. People adapt to heat by adopting various relief measures in their daily lives including changing their behaviour. Many labour intensive outdoor industries implement standards for heat stress management for their workforce. However, little is known about how people cope with heat at their workplaces apart from studies targeting some specific industries where labourers are exposed to extreme heat. Here, we analysed responses from 1719 people in the Australian labour force to self-reported heat stress and associated coping mechanisms. Three quarters of respondents experienced heat stress at their workplace with fatigue and headache being the two most frequently stated symptoms. Almost all of those who were affected by heat would hydrate (88%), 67% would cool, and 44% would rest as a strategy for coping with heat. About 10% intended to change their jobs because of heat stress in the workplace. We found differences in heat relief measures across gender, education, health, level of physical intensity of job, and time spent working outside. People working in jobs that were not very demanding physically were more likely to choose cooling down as a relief measure, while those in labour intensive jobs and jobs that required considerable time outside were more likely to rest. This has potential consequences for their productivity and work schedules. Heat affects work in Australia in many types of industry with impact dependent on workforce acclimatisation, yet public awareness and work relief plans are often limited to outdoor and labour intensive industries. Industries and various levels of government in all sectors need to implement standards for heat management specific to climate zones to help people cope better with high temperatures as well as plan strategies in anticipation of projected temperature increases. PMID:29495396

Exploring Heat Stress Relief Measures among the Australian Labour Force.

PubMed

Zander, Kerstin K; Mathew, Supriya; Garnett, Stephen T

2018-02-26

Australia experiences frequent heat waves and generally high average temperatures throughout the continent with substantial impacts on human health and the economy. People adapt to heat by adopting various relief measures in their daily lives including changing their behaviour. Many labour intensive outdoor industries implement standards for heat stress management for their workforce. However, little is known about how people cope with heat at their workplaces apart from studies targeting some specific industries where labourers are exposed to extreme heat. Here, we analysed responses from 1719 people in the Australian labour force to self-reported heat stress and associated coping mechanisms. Three quarters of respondents experienced heat stress at their workplace with fatigue and headache being the two most frequently stated symptoms. Almost all of those who were affected by heat would hydrate (88%), 67% would cool, and 44% would rest as a strategy for coping with heat. About 10% intended to change their jobs because of heat stress in the workplace. We found differences in heat relief measures across gender, education, health, level of physical intensity of job, and time spent working outside. People working in jobs that were not very demanding physically were more likely to choose cooling down as a relief measure, while those in labour intensive jobs and jobs that required considerable time outside were more likely to rest. This has potential consequences for their productivity and work schedules. Heat affects work in Australia in many types of industry with impact dependent on workforce acclimatisation, yet public awareness and work relief plans are often limited to outdoor and labour intensive industries. Industries and various levels of government in all sectors need to implement standards for heat management specific to climate zones to help people cope better with high temperatures as well as plan strategies in anticipation of projected temperature increases.

Beam Energy Scan of Specific Heat Through Temperature Fluctuations in Heavy Ion Collisions

NASA Astrophysics Data System (ADS)

Basu, Sumit; Nandi, Basanta K.; Chatterjee, Sandeep; Chatterjee, Rupa; Nayak, Tapan

2016-01-01

Temperature fluctuations may have two distinct origins, first, quantum fluctuations that are initial state fluctuations, and second, thermodynamical fluctuations. We discuss a method of extracting the thermodynamic temperature from the mean transverse momentum of pions, by using controllable parameters such as centrality of the system, and range of the transverse momenta. Event-by-event fluctuations in global temperature over a large phase space provide the specific heat of the system. We present Beam Energy Scan of specific heat from data, AMPT and HRG model prediction. Experimental results from NA49, STAR, PHENIX, PHOBOS and ALICE are combined to obtain the specific heat as a function of beam energy. These results are compared to calculations from AMPT event generator, HRG model and lattice calculations, respectively.

Modeling heat transfer and inactivation of Escherichia coli O157:H7 in precooked meat products in Argentina using the finite element method.

PubMed

Santos, M V; Zaritzky, N; Califano, A

2008-07-01

The presence of Escherichia coli is linked with sanitary deficiencies and undercooking of meat products. Recent studies have detected E. coli O157:H7 in black blood sausages. Minimum time-temperature specifications to kill the bacteria were obtained by numerical simulations of the microscopic heat conduction equation using the finite element method, and calculating the temperature profile of the sausage and the population of E. coli at the coldest point during heating. The model was validated by heating sausages in a water-bath. The effects of heat transfer coefficients and water temperatures on the required time to achieve an inactivation value (IV) of 12(log) are reported. Macroscopic heat balances were simultaneously solved to consider the temperature drop in the water batch as a function of the ratio between the mass of thermally treated sausage and the heat capacity of the system.

The effects of glutathione depletion on thermotolerance and heat stress protein synthesis.

PubMed Central

Russo, A.; Mitchell, J. B.; McPherson, S.

1984-01-01

The effects of cellular glutathione depletion by buthionine sulfoximine on the development of thermotolerance and synthesis of heat stress protein was studied. Cellular glutathione levels were found to increase rapidly following an acute heat treatment of either 12 min at 45.5 degrees C or 1 h at 43 degrees C and remain elevated for prolonged periods. Glutathione depletion and prevention of glutathione synthesis by buthionine sulfoximine resulted in inhibition of the development of thermotolerance and a decrease in total protein as well as specific heat stress proteins. While the degree of inhibition of thermotolerance was similar for both glutathione depletion protocols, inhibition in heat stress protein synthesis was greater when glutathione was depleted to low levels prior to heating. The possible role of glutathione and the cellular redox state to thermotolerance and synthesis of heat stress protein is discussed. Images Figure 2 PMID:6733022

The influence of a wall function on turbine blade heat transfer prediction

NASA Technical Reports Server (NTRS)

Whitaker, Kevin W.

1989-01-01

The second phase of a continuing investigation to improve the prediction of turbine blade heat transfer coefficients was completed. The present study specifically investigated how a numeric wall function in the turbulence model of a two-dimensional boundary layer code, STAN5, affected heat transfer prediction capabilities. Several sources of inaccuracy in the wall function were identified and then corrected or improved. Heat transfer coefficient predictions were then obtained using each one of the modifications to determine its effect. Results indicated that the modifications made to the wall function can significantly affect the prediction of heat transfer coefficients on turbine blades. The improvement in accuracy due the modifications is still inconclusive and is still being investigated.

Heat transfer and evaporative cooling in the function of pot-in-pot coolers

NASA Astrophysics Data System (ADS)

Chemin, Arsène; Levy Dit Vehel, Victor; Caussarieu, Aude; Plihon, Nicolas; Taberlet, Nicolas

2018-03-01

A pot-in-pot cooler is an affordable electricity-free refrigerator which uses the latent heat of vaporization of water to maintain a low temperature inside an inner compartment. In this article, we experimentally investigate the influence of the main physical parameters in model pot-in-pot coolers. The effect of the wind on the evaporation rate of the cooling fluid is studied in model experiments while the influence of the fluid properties (thermal conductivity, specific heat, and latent heat) is elucidated using a variety of cooling fluids (water, ethanol, and ether). A model based on a simplified heat conduction equation is proposed and is shown to be in good quantitative agreement with the experimental measurements.

Liquid belt radiator design study

NASA Technical Reports Server (NTRS)

Teagan, W. P.; Fitzgerald, K. F.

1986-01-01

The Liquid Belt Radiator (LBR) is an advanced concept developed to meet the needs of anticipated future space missions. A previous study documented the advantages of this concept as a lightweight, easily deployable alternative to present day space heat rejection systems. The technical efforts associated with this study concentrate on refining the concept of the LBR as well as examining the issues of belt dynamics and potential application of the LBR to intermediate and high temperature heat rejection applications. A low temperature point design developed in previous work is updated assuming the use of diffusion pump oil, Santovac-6, as the heat transfer media. Additional analytical and design effort is directed toward determining the impact of interface heat exchanger, fluid bath sealing, and belt drive mechanism designs on system performance and mass. The updated design supports the earlier result by indicating a significant reduction in system specific system mass as compared to heat pipe or pumped fluid radiator concepts currently under consideration (1.3 kg/sq m versus 5 kg/sq m).

Evaluation of structural and thermophysical effects on the measurement accuracy of deep body thermometers based on dual-heat-flux method.

PubMed

Huang, Ming; Tamura, Toshiyo; Chen, Wenxi; Kanaya, Shigehiko

2015-01-01

To help pave a path toward the practical use of continuous unconstrained noninvasive deep body temperature measurement, this study aims to evaluate the structural and thermophysical effects on measurement accuracy for the dual-heat-flux method (DHFM). By considering the thermometer's height, radius, conductivity, density and specific heat as variables affecting the accuracy of DHFM measurement, we investigated the relationship between those variables and accuracy using 3-D models based on finite element method. The results of our simulation study show that accuracy is proportional to the radius but inversely proportional to the thickness of the thermometer when the radius is less than 30.0mm, and is also inversely proportional to the heat conductivity of the heat insulator inside the thermometer. The insights from this study would help to build a guideline for design, fabrication and optimization of DHFM-based thermometers, as well as their practical use. Copyright © 2014 Elsevier Ltd. All rights reserved.

Day and night heat stress trigger different transcriptomic responses in green and ripening grapevine (vitis vinifera) fruit.

PubMed

Rienth, Markus; Torregrosa, Laurent; Luchaire, Nathalie; Chatbanyong, Ratthaphon; Lecourieux, David; Kelly, Mary T; Romieu, Charles

2014-04-28

Global climate change will noticeably affect plant vegetative and reproductive development. The recent increase in temperatures has already impacted yields and composition of berries in many grapevine-growing regions. Physiological processes underlying temperature response and tolerance of the grapevine fruit have not been extensively investigated. To date, all studies investigating the molecular regulation of fleshly fruit response to abiotic stress were only conducted during the day, overlooking possible critical night-specific variations. The present study explores the night and day transcriptomic response of grapevine fruit to heat stress at several developmental stages. Short heat stresses (2 h) were applied at day and night to vines bearing clusters sequentially ordered according to the developmental stages along their vertical axes. The recently proposed microvine model (DRCF-Dwarf Rapid Cycling and Continuous Flowering) was grown in climatic chambers in order to circumvent common constraints and biases inevitable in field experiments with perennial macrovines. Post-véraison berry heterogeneity within clusters was avoided by constituting homogenous batches following organic acids and sugars measurements of individual berries. A whole genome transcriptomic approach was subsequently conducted using NimbleGen 090818 Vitis 12X (30 K) microarrays. Present work reveals significant differences in heat stress responsive pathways according to day or night treatment, in particular regarding genes associated with acidity and phenylpropanoid metabolism. Precise distinction of ripening stages led to stage-specific detection of malic acid and anthocyanin-related transcripts modulated by heat stress. Important changes in cell wall modification related processes as well as indications for heat-induced delay of ripening and sugar accumulation were observed at véraison, an effect that was reversed at later stages. This first day - night study on heat stress adaption of the grapevine berry shows that the transcriptome of fleshy fruits is differentially affected by abiotic stress at night. The present results emphasize the necessity of including different developmental stages and especially several daytime points in transcriptomic studies.

Summer indoor heat exposure and respiratory and cardiovascular distress calls in New York City, NY, U.S

PubMed Central

Uejio, C. K.; Tamerius, J. D.; Vredenburg, J.; Asaeda, G.; Isaacs, D. A.; Braun, J.; Quinn, A.; Freese, J. P.

2016-01-01

Most extreme heat studies relate outdoor weather conditions to human morbidity and mortality. In developed nations, individuals spend ~90% of their time indoors. This pilot study investigated the indoor environments of people receiving emergency medical care in New York City, NY, U.S., from July to August 2013. The first objective was to determine the relative influence of outdoor conditions as well as patient characteristics and neighborhood sociodemographics on indoor temperature and specific humidity (N = 764). The second objective was to determine whether cardiovascular or respiratory cases experience hotter and more humid indoor conditions as compared to controls. Paramedics carried portable sensors into buildings where patients received care to passively monitor indoor temperature and humidity. The case–control study compared 338 respiratory cases, 291 cardiovascular cases, and 471 controls. Intuitively, warmer and sunnier outdoor conditions increased indoor temperatures. Older patients who received emergency care tended to occupy warmer buildings. Indoor-specific humidity levels quickly adjusted to outdoor conditions. Indoor heat and humidity exposure above a 26 °C threshold increased (OR: 1.63, 95% CI: 0.98–2.68, P = 0.056), but not significantly, the proportion of respiratory cases. Indoor heat exposures were similar between cardiovascular cases and controls. PMID:26086869

Strain Modulation of Electronic and Heat Transport Properties of Bilayer Boronitrene

NASA Astrophysics Data System (ADS)

Yang, Ming; Sun, Fang-Yuan; Wang, Rui-Ning; Zhang, Hang; Tang, Da-Wei

2017-10-01

Strain engineering has been proven as an effective approach to modify electronic and thermal properties of materials. Recently, strain effects on two-dimensional materials have become important relevant topics in this field. We performed density functional theory studies on the electronic and heat transport properties of bilayer boronitrene samples under an isotropic strain. We demonstrate that the strain will reduce the band gap width but keep the band gap type robust and direct. The strain will enhance the thermal conductivity of the system because of the increase in specific heat. The thermal conductivity was studied as a function of the phonon mean-free path.

Study of heating capacity of focused IR light soldering systems.

PubMed

Anguiano, C; Félix, M; Medel, A; Bravo, M; Salazar, D; Márquez, H

2013-10-07

An experimental study about four optical setups used for developing a Focused IR Light Soldering System (FILSS) for Surface Mount Technology (SMT) lead-free electronic devices specifically for Ball Grid Arrays (BGA) is presented. An analysis of irradiance and infrared thermography at BGA surface is presented, as well as heat transfer by radiation and conduction process from the surface of the BGA to the solder balls. The results of this work show that the heating provided by our proposed optical setups, measured at the BGA under soldering process, meets the high temperature and uniform thermal distribution requirements, which are defined by the reflow solder method for SMT devices.

Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells

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

Kupenko, I., E-mail: kupenko@esrf.fr; Strohm, C.; ESRF-The European Synchrotron, CS 40220, 38043 Grenoble Cedex 9

2015-11-15

Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamondmore » anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe{sub 3}C using synchrotron Mössbauer source spectroscopy, FeCO{sub 3} using nuclear inelastic scattering, and Fe{sub 2}O{sub 3} using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses.« less

SIRT1 activation mediates heat-induced survival of UVB damaged Keratinocytes.

PubMed

Calapre, Leslie; Gray, Elin S; Kurdykowski, Sandrine; David, Anthony; Descargues, Pascal; Ziman, Mel

2017-06-10

Exposure to heat stress after UVB irradiation induces a reduction of apoptosis, resulting in survival of DNA damaged human keratinocytes. This heat-mediated evasion of apoptosis appears to be mediated by activation of SIRT1 and inactivation of p53 signalling. In this study, we assessed the role of SIRT1 in the inactivation of p53 signalling and impairment of DNA damage response in UVB plus heat exposed keratinocytes. Activation of SIRT1 after multiple UVB plus heat exposures resulted in increased p53 deacetylation at K382, which is known to affect its binding to specific target genes. Accordingly, we noted decreased apoptosis and down regulation of the p53 targeted pro-apoptotic gene BAX and the DNA repair genes ERCC1 and XPC after UVB plus heat treatments. In addition, UVB plus heat induced increased expression of the cell survival gene Survivin and the proliferation marker Ki67. Notably, keratinocytes exposed to UVB plus heat in the presence of the SIRT1 inhibitor, Ex-527, showed a similar phenotype to those exposed to UV alone; i.e. an increase in p53 acetylation, increased apoptosis and low levels of Survivin. This study demonstrate that heat-induced SIRT1 activation mediates survival of DNA damaged keratinocytes through deacetylation of p53 after exposure to UVB plus heat.

Proton Beam Driven Isochoric Heating to Warm Dense Matter Conditions on Texas Petawatt

NASA Astrophysics Data System (ADS)

Roycroft, R.; Dyer, G. M.; McCary, E.; Jiao, X.; Bowers, B.; Bernstein, A.; Ditmire, T.; Montgomery, M.; Winget, D.; Hegelich, B. M.

2017-10-01

Isochoric heating of solids and gases to warm dense matter conditions is relevant to the study of equation of state as well as laboratory astrophysics, specifically heating of hydrogen gas ( 1017-1019 cm3) to 0.5-3eV for the study of white dwarf atmospheres. In a series of experiments on Texas Petawatt, we have built a platform using the petawatt laser focused softly to a large focal spot (60-70um) to generate large numbers of intermediate energy protons via TNSA, ideal for isochoric heating. We have previously used the proton beam to isochorically heat 10um aluminum foils to 20eV. This poster presents results of experiments in which low Z materials such as methane gas, carbon foams, and hydrogen are heated using this platform. We are measuring the surface brightness temperature and heating with a streaked optical pyrometer, and XUV emissions using an XUV spectrometer. Supported by NNSA cooperative agreement DE-NA0002008, the DARPA PULSE program (12-63-PULSE-FP014), and the Air Force Office of Scientific Research (FA9550-14-1-0045).

Differences among heat-treated, raw, and commercial peanut extracts by skin testing and immunoblotting.

PubMed

Maleki, Soheila J; Casillas, Adrian M; Kaza, Ujwala; Wilson, Brian A; Nesbit, Jacqueline B; Reimoneqnue, Chantrel; Cheng, Hsiaopo; Bahna, Sami L

2010-12-01

Peanut allergenicity has been reported to be influenced by heat treatment, yet the commonly available extracts for skin prick testing (SPT) are derived from raw extracts. To assess the effect of heat treatment on the SPT reactivity and specific IgE binding to peanut. Three commercial extracts and 3 laboratory-prepared extracts, including raw, roasted, and boiled, were used for SPT in 19 patients with suspected peanut allergy and in 4 individuals who eat peanut without any symptoms. Serum samples were obtained to measure total IgE in addition to specific IgE binding to the study extracts by immunoblotting. Peanut allergy was confirmed with challenge test unless the individual had a convincing history of a severe reaction. Eleven study participants were considered peanut allergic based on a strong history or positive challenge test result. SPT with the prepared and commercial reagents showed that the boiled extract had the highest specificity (67% vs 42%-63% for the other extracts). The prepared extracts showed similar SPT sensitivity (81%). Three patients with a history of severe reaction and elevated specific IgE levels to peanut to the 3 study extracts had variable SPT reactivity to 1 or more of the commercial extracts. IgE binding to Ara h 2 was found in nearly all patients, regardless of their clinical reactivity. None of the extracts tested showed optimal diagnostic reliability regarding both sensitivity and specificity. Perhaps testing should be performed with multiple individual extracts prepared by different methods. Copyright © 2010 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Spin-State Transition in La1-xSrxCoO3 Single Crystals

NASA Astrophysics Data System (ADS)

Bhardwaj, S.; Prabhakaran, D.; Awasthi, A. M.

2011-07-01

We present a study of the thermal conductivity (κ), specific heat (Cp) and Raman spectra of La1-xSrxCoO3 (x = 0,0.1) single crystals. Both the specimens have low thermal conductivity and board Raman peaks, arising from strong scattering of phonons by lattice disorder, produced by (and doping-enhanced) spin-states admixture of the Co3+ ions. The thermal conductivity anomalously deviates from ˜1/T behaviour at high (room) temperatures, expected of an insulator. High-temperature specific heat reveals large decrease in the metal-insulator (M-I) transition temperature with Sr-doping.

Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

DTIC Science & Technology

2011-02-22

A. H. Nayfeh. Nonparallel stability of boundary layers with pressure gradients and suction. Technical Report AGARD - CP -224, 1977. [Squ33] H. B. Squire...only. µ = µr ( T Tr )3/2 Tr + Ts T + Ts , (2.13) 8 K = µcp Pr , (2.14) where µr = 1.7894 × 10−5 Ns/m2, Tr = 288.0 K, Ts = 110.33 K, and cp is the...fraction of species s Cpf = frozen specific heat, cal/g-mole-K Cp ,s = specific heat at constant pressure of species s, cal/g-mole Dij = binary diffusion

Quantifying variety-specific heat resistance and the potential for adaptation to climate change.

PubMed

Tack, Jesse; Barkley, Andrew; Rife, Trevor W; Poland, Jesse A; Nalley, Lawton Lanier

2016-08-01

The impact of climate change on crop yields has become widely measured; however, the linkages for winter wheat are less studied due to dramatic weather changes during the long growing season that are difficult to model. Recent research suggests significant reductions under warming. A potential adaptation strategy involves the development of heat resistant varieties by breeders, combined with alternative variety selection by producers. However, the impact of heat on specific wheat varieties remains relatively unstudied due to limited data and the complex genetic basis of heat tolerance. Here, we provide a novel econometric approach that combines field-trial data with a genetic cluster mapping to group wheat varieties and estimate a separate extreme heat impact (temperatures over 34 °C) across 24 clusters spanning 197 varieties. We find a wide range of heterogeneous heat resistance and a trade-off between average yield and resistance. Results suggest that recently released varieties are less heat resistant than older varieties, a pattern that also holds for on-farm varieties. Currently released - but not yet adopted - varieties do not offer improved resistance relative to varieties currently grown on farm. Our findings suggest that warming impacts could be significantly reduced through advances in wheat breeding and/or adoption decisions by producers. However, current adaptation-through-adoption potential is limited under a 1 °C warming scenario as increased heat resistance cannot be achieved without a reduction in average yields. © 2015 John Wiley & Sons Ltd.

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

External heating of stents by radio waves Pilot studies in rabbit aorta

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

Levitt, Adam B.; Robinson, Keith; Chronos, Nicolas A.F.

Purpose: This experiment was designed to assess the feasibility of radio frequency energy delivered by a prototype radio frequency generator inductive heating device (REVAX) positioned external to the body, for transient heating of stents after arterial implant. Methods and Materials: Twenty-one New Zealand White rabbits underwent stenting of their infrarenal aorta. Nine rabbits were stented and immediately placed in the REVAX for external stent heating with internal temperature probes in place. Twelve rabbits were stented and 3 days later either heated or placed in the generator as a sham for 20 min. The animals were terminated 28 days later. Results:more » The REVAX was able to heat the aortic stents in a controlled fashion; in Phase II experiments, the stent temperature was raised to 42 deg. C for 20 min. In Phase I mild necrosis was noted at the stent struts. In Phase II, necrosis and mineralization of the media was seen at the stent struts, and evidence of neointimal suppression was observed. Conclusion: This study demonstrated that external heating of stents in a blood vessel in a live animal via radio frequency energy is feasible. Further studies will be needed to assess whether any specific heating regimen might inhibit fibrocellular neointimal hyperplasia.« less

Is Children's Naive Knowledge Consistent?: A Comparison of the Concepts of Sound and Heat

ERIC Educational Resources Information Center

Lautrey, Jacques; Mazens, Karine

2004-01-01

The aim of this study was to shed some light on the organization of naive knowledge, and on the process of conceptual change in everyday physics, more specifically regarding the concepts of sound and heat. Eighty-three 8-year-old children were interviewed individually in order to see if they attributed the properties of objects (such as…

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

Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants

NASA Astrophysics Data System (ADS)

Ilmov, D. N.; Mamontov, Yu. N.; Skorohodov, A. S.; Smolyarov, V. A.; Filatov, N. I.

2016-01-01

The specifics of operation (high temperatures in excess of 1000 K and large pressure drops of several megapascals between "hot" and "cold" coolant paths) of heat exchangers in the closed circuit of a gasturbine power converter operating in accordance with the Brayton cycle with internal heat recovery are analyzed in the context of construction of space propulsion systems. The design of a heat-exchange matrix made from doubly convex stamped plates with a specific surface relief is proposed. This design offers the opportunity to construct heat exchangers with the required parameters (strength, rigidity, weight, and dimensions) for the given operating conditions. The diagram of the working area of a test bench is presented, and the experimental techniques are outlined. The results of experimental studies of heat exchange and flow regimes in the models of heat exchangers with matrices containing 50 and 300 plates for two pairs of coolants (gas-gas and gas-liquid) are detailed. A criterion equation for the Nusselt number in the range of Reynolds numbers from 200 to 20 000 is proposed. The coefficients of hydraulic resistance for each coolant path are determined as functions of the Reynolds number. It is noted that the pressure in the water path in the "gas-liquid" series of experiments remained almost constant. This suggests that no well-developed processes of vaporization occurred within this heat-exchange matrix design even when the temperature drop between gas and water was as large as tens or hundreds of degrees. The obtained results allow one to design flight heat exchangers for various space power plants.

Decay heat uncertainty for BWR used fuel due to modeling and nuclear data uncertainties

DOE PAGES

Ilas, Germina; Liljenfeldt, Henrik

2017-05-19

Characterization of the energy released from radionuclide decay in nuclear fuel discharged from reactors is essential for the design, safety, and licensing analyses of used nuclear fuel storage, transportation, and repository systems. There are a limited number of decay heat measurements available for commercial used fuel applications. Because decay heat measurements can be expensive or impractical for covering the multitude of existing fuel designs, operating conditions, and specific application purposes, decay heat estimation relies heavily on computer code prediction. Uncertainty evaluation for calculated decay heat is an important aspect when assessing code prediction and a key factor supporting decision makingmore » for used fuel applications. While previous studies have largely focused on uncertainties in code predictions due to nuclear data uncertainties, this study discusses uncertainties in calculated decay heat due to uncertainties in assembly modeling parameters as well as in nuclear data. Capabilities in the SCALE nuclear analysis code system were used to quantify the effect on calculated decay heat of uncertainties in nuclear data and selected manufacturing and operation parameters for a typical boiling water reactor (BWR) fuel assembly. Furthermore, the BWR fuel assembly used as the reference case for this study was selected from a set of assemblies for which high-quality decay heat measurements are available, to assess the significance of the results through comparison with calculated and measured decay heat data.« less

Decay heat uncertainty for BWR used fuel due to modeling and nuclear data uncertainties

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

Ilas, Germina; Liljenfeldt, Henrik

Characterization of the energy released from radionuclide decay in nuclear fuel discharged from reactors is essential for the design, safety, and licensing analyses of used nuclear fuel storage, transportation, and repository systems. There are a limited number of decay heat measurements available for commercial used fuel applications. Because decay heat measurements can be expensive or impractical for covering the multitude of existing fuel designs, operating conditions, and specific application purposes, decay heat estimation relies heavily on computer code prediction. Uncertainty evaluation for calculated decay heat is an important aspect when assessing code prediction and a key factor supporting decision makingmore » for used fuel applications. While previous studies have largely focused on uncertainties in code predictions due to nuclear data uncertainties, this study discusses uncertainties in calculated decay heat due to uncertainties in assembly modeling parameters as well as in nuclear data. Capabilities in the SCALE nuclear analysis code system were used to quantify the effect on calculated decay heat of uncertainties in nuclear data and selected manufacturing and operation parameters for a typical boiling water reactor (BWR) fuel assembly. Furthermore, the BWR fuel assembly used as the reference case for this study was selected from a set of assemblies for which high-quality decay heat measurements are available, to assess the significance of the results through comparison with calculated and measured decay heat data.« less

Study toward high-performance thermally driven air-conditioning systems

NASA Astrophysics Data System (ADS)

Miyazaki, Takahiko; Miyawaki, Jin; Ohba, Tomonori; Yoon, Seong-Ho; Saha, Bidyut Baran; Koyama, Shigeru

2017-01-01

The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced.

Modified Laser Flash Method for Thermal Properties Measurements and the Influence of Heat Convection

NASA Technical Reports Server (NTRS)

Lin, Bochuan; Zhu, Shen; Ban, Heng; Li, Chao; Scripa, Rosalia N.; Su, Ching-Hua; Lehoczky, Sandor L.

2003-01-01

The study examined the effect of natural convection in applying the modified laser flash method to measure thermal properties of semiconductor melts. Common laser flash method uses a laser pulse to heat one side of a thin circular sample and measures the temperature response of the other side. Thermal diffusivity can be calculations based on a heat conduction analysis. For semiconductor melt, the sample is contained in a specially designed quartz cell with optical windows on both sides. When laser heats the vertical melt surface, the resulting natural convection can introduce errors in calculation based on heat conduction model alone. The effect of natural convection was studied by CFD simulations with experimental verification by temperature measurement. The CFD results indicated that natural convection would decrease the time needed for the rear side to reach its peak temperature, and also decrease the peak temperature slightly in our experimental configuration. Using the experimental data, the calculation using only heat conduction model resulted in a thermal diffusivity value is about 7.7% lower than that from the model with natural convection. Specific heat capacity was about the same, and the difference is within 1.6%, regardless of heat transfer models.

Structural and magnetic transitions in spinel FeM n 2 O 4 single crystals

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

Nepal, Roshan; Zhang, Qiang; Dai, Samuel

Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeMn 2O 4 undergoes one structural and two magnetic transitions. The structural transition occurs at T s ~595K from cubic at high temperatures to tetragonal at low temperatures. Here, two magnetic transitions are ferrimagnetic at T FI–1 ~373K and T FI–2 ~50K, respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to themore » low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations.« less

Effect of Moisture Content on Thermal Properties of Porous Building Materials

NASA Astrophysics Data System (ADS)

Kočí, Václav; Vejmelková, Eva; Čáchová, Monika; Koňáková, Dana; Keppert, Martin; Maděra, Jiří; Černý, Robert

2017-02-01

The thermal conductivity and specific heat capacity of characteristic types of porous building materials are determined in the whole range of moisture content from dry to fully water-saturated state. A transient pulse technique is used in the experiments, in order to avoid the influence of moisture transport on measured data. The investigated specimens include cement composites, ceramics, plasters, and thermal insulation boards. The effect of moisture-induced changes in thermal conductivity and specific heat capacity on the energy performance of selected building envelopes containing the studied materials is then analyzed using computational modeling of coupled heat and moisture transport. The results show an increased moisture content as a substantial negative factor affecting both thermal properties of materials and energy balance of envelopes, which underlines the necessity to use moisture-dependent thermal parameters of building materials in energy-related calculations.

PIP-II Cryogenic System and the evolution of Superfluid Helium Cryogenic Plant Specifications

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

Chakravarty, Anindya; Rane, Tejas; Klebaner, Arkadiy

2017-07-06

The PIP-II cryogenic system consists of a Superfluid Helium Cryogenic Plant (SHCP) and a Cryogenic Distribution System (CDS) connecting the SHCP to the Superconducting (SC) Linac consisting of 25 cryomodules. The dynamic heat load of the SC cavities for continuous wave (CW) as well as pulsed mode of operation has been listed out. The static heat loads of the cavities along with the CDS have also been discussed. Simulation study has been carried out to compute the supercritical helium (SHe) flow requirements for each cryomodule. Comparison between the flow requirements of the cryomodules for the CW and pulsed modes ofmore » operation have also been made. From the total computed heat load and pressure drop values in the CDS, the basic specifications for the SHCP, required for cooling the SC Linac, have evolved.« less

Structural and magnetic transitions in spinel FeM n 2 O 4 single crystals

DOE PAGES

Nepal, Roshan; Zhang, Qiang; Dai, Samuel; ...

2018-01-11

Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeMn 2O 4 undergoes one structural and two magnetic transitions. The structural transition occurs at T s ~595K from cubic at high temperatures to tetragonal at low temperatures. Here, two magnetic transitions are ferrimagnetic at T FI–1 ~373K and T FI–2 ~50K, respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to themore » low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations.« less

Nonlinear convective flows in a two-layer system under the action of spatial temperature modulation of heat release/consumption at the interface

NASA Astrophysics Data System (ADS)

Simanovskii, Ilya B.; Viviani, Antonio; Dubois, Frank

2018-06-01

An influence of a spatial temperature modulation of the interfacial heat release/consumption on nonlinear convective flows in the 47v2 silicone oil - water system, is studied. Rigid heat-insulated lateral walls, corresponding to the case of closed cavities, have been considered. Transitions between the flows with different spatial structures, have been investigated. It is shown that the spatial modulation can change the sequence of bifurcations and lead to the appearance of specific steady and oscillatory flows in the system.

The influence of climatic conditions on the heat balance of the human body

NASA Astrophysics Data System (ADS)

Blażejeczyk, Krzysztof; Krawczyk, Barbara

1991-06-01

The structure of heat exchange between the human body and its surroundings has been studied according to M.I. Budyko's model. Comparative measurements were carried out in the Polish Lakeland (maritime, temperate warm climate), in Central Mongolia (continental, temperate cool climate), and in the Kara Kum desert (dry subtropical climate). The results deal with the summer and early autumn seasons. The calculations indicate that the quantitative apportionment of various forms of heat exchange depend on specific weather conditions, which are typical for the distinguished climatic zones.

First order transitions by conduction calorimetry: Application to deuterated potassium dihydrogen phosphate ferroelastic crystal under uniaxial pressure

NASA Astrophysics Data System (ADS)

Gallardo, M. C.; Jiménez, J.; Koralewski, M.; del Cerro, J.

1997-03-01

The specific heat c and the heat power W exchanged by a Deuterated Potassium Dihydrogen Phosphate ferroelectric-ferroelastic crystal have been measured simultaneously for both decreasing and increasing temperature at a low constant rate (0.06 K/h) between 175 and 240 K. The measurements were carried out under controlled uniaxial stresses of 0.3 and 4.5±0.1 bar applied to face (110). At Tt=207.9 K, a first order transition is produced with anomalous specific heat behavior in the interval where the transition heat appears. This anomalous behavior is explained in terms of the temperature variation of the heat power during the transition. During cooling, the transition occurs with coexistence of phases, while during heating it seems that metastable states are reached. Excluding data affected by the transition heat, the specific heat behavior agrees with the predictions of a 2-4-6 Landau potential in the range of 4-15 K below Tt while logarithmic behavior is obtained in the range from Tt to 1 K below Tt. Data obtained under 0.3 and 4.5 bar uniaxial stresses exhibit the same behavior.

A validated methodology for the prediction of heating and cooling energy demand for buildings within the Urban Heat Island: Case-study of London

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

Kolokotroni, Maria; Bhuiyan, Saiful; Davies, Michael

2010-12-15

This paper describes a method for predicting air temperatures within the Urban Heat Island at discreet locations based on input data from one meteorological station for the time the prediction is required and historic measured air temperatures within the city. It uses London as a case-study to describe the method and its applications. The prediction model is based on Artificial Neural Network (ANN) modelling and it is termed the London Site Specific Air Temperature (LSSAT) predictor. The temporal and spatial validity of the model was tested using data measured 8 years later from the original dataset; it was found thatmore » site specific hourly air temperature prediction provides acceptable accuracy and improves considerably for average monthly values. It thus is a very reliable tool for use as part of the process of predicting heating and cooling loads for urban buildings. This is illustrated by the computation of Heating Degree Days (HDD) and Cooling Degree Hours (CDH) for a West-East Transect within London. The described method could be used for any city for which historic hourly air temperatures are available for a number of locations; for example air pollution measuring sites, common in many cities, typically measure air temperature on an hourly basis. (author)« less

Heat pipe cooled power magnetics

NASA Technical Reports Server (NTRS)

Chester, M. S.

1979-01-01

A high frequency, high power, low specific weight (0.57 kg/kW) transformer developed for space use was redesigned with heat pipe cooling allowing both a reduction in weight and a lower internal temperature rise. The specific weight of the heat pipe cooled transformer was reduced to 0.4 kg/kW and the highest winding temperature rise was reduced from 40 C to 20 C in spite of 10 watts additional loss. The design loss/weight tradeoff was 18 W/kg. Additionally, allowing the same 40 C winding temperature rise as in the original design, the KVA rating is increased to 4.2 KVA, demonstrating a specific weight of 0.28 kg/kW with the internal loss increased by 50W. This space environment tested heat pipe cooled design performed as well electrically as the original conventional design, thus demonstrating the advantages of heat pipes integrated into a high power, high voltage magnetic. Another heat pipe cooled magnetic, a 3.7 kW, 20A input filter inductor was designed, developed, built, tested, and described. The heat pipe cooled magnetics are designed to be Earth operated in any orientation.

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

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

Urban Heat Wave Hazard Assessment

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Jedlovec, Gary; Meyer, Paul J.; LaFontaine, Frank J.; Crane, Dakota L.

2016-01-01

Heat waves are the largest cause of environment-related deaths globally. On average, over 6,000 people in the United States alone are hospitalized each summer due to excessive heat. Key elements leading to these disasters are elevated humidity and the urban heat island effect, which act together to increase apparent temperature and amplify the effects of a heat wave. Urban demographics and socioeconomic factors also play a role in determining individual risk. Currently, advisories of impending heat waves are often too generalized, with limited or no spatial variability over urban regions. This frequently contributes to a lack of specific response on behalf of the population. A goal of this project is to develop a product that has the potential to provide more specific heat wave guidance invoking greater awareness and action.

The relevance of rooftops: Analyzing the microscale surface energy balance in the Chicago region

NASA Astrophysics Data System (ADS)

Khosla, Radhika

Spatial structure in climate variables often exist over very short length scales within an urban area, and this structure is a result of various site-specific features. In order to analyze the seasonal and diurnal energy flows that take place at a microclimatic surface, this work develops a semi-empirical energy balance model. For this, radiation fluxes and meteorological measurements are determined by direct observation; sensible heat and latent heat fluxes by parameterizations; and the heat storage flux by a 1-D mechanistic model that allows analysis of the temperature profile and heat storage within an underlying slab. Two sites receive detailed study: an anthropogenic site, being a University of Chicago building rooftop, and a natural site, outside Chicago in the open country. Two identical sets of instruments record measurements contemporaneously from these locations during June-November 2007, the entire period for which analyses are carried out. The study yields seasonal trends in surface temperature, surface-to-air temperature contrast and net radiation. At both sites, a temporal hysteresis between net radiation and heat storage flux indicates that surplus energy absorbed during daylight is released to the atmosphere later in the evening. The surface energy balance model responds well to site specific features for both locations. An analysis of the surface energy balance shows that the flux of sensible heat is the largest non-radiative contributor to the roof's surface cooling, while the flux of latent heat (also referred to as evaporative cooling) is the largest heat sink for the soil layer. In the latter part of the study, the surface energy balance model is upgraded by adding the capability to compute changes in surface temperature and non-radiative fluxes for any specified set of thermal and reflective roof properties. The results of this analysis allow an examination of the relationship between the roof temperature, the heat flux entering the building interior through the roof, and the physical properties of the surface. These results hold particular relevance for urban heat island mitigation strategies. Based on the results of this work, recommendations are proposed for widespread adoption of various techniques that enhance building energy efficiency (particularly targeting rooftops), mitigate the negative impacts of the urban heat island, and overcome the current barriers to transforming the market.

Specific heat of ovendry loblolly pine wood

Treesearch

Charles W. McMillin

1969-01-01

In the range of 333 K to 413 K, the specific heat of ovendry loblolly pine (Pinus taeda L.) wood was expressed by a linear function of temperature. No relationship was detected with specific gravity, growth rate, or distance from the pith; nor were differences found between earlywood and latewood.

49 CFR 179.300-10 - Postweld heat treatment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-10 Postweld heat treatment... as a unit in compliance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR...

49 CFR 179.200-11 - Postweld heat treatment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-11 Postweld heat treatment... with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this...

49 CFR 179.220-11 - Postweld heat treatment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-11 Postweld heat treatment... attached must comply with AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter...

49 CFR 179.300-10 - Postweld heat treatment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-10 Postweld heat treatment... as a unit in compliance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR...

49 CFR 179.200-11 - Postweld heat treatment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-11 Postweld heat treatment... with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this...

49 CFR 179.200-11 - Postweld heat treatment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-11 Postweld heat treatment... with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this...

Spin morphologies and heat dissipation in spherical assemblies of magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Anand, Manish; Carrey, Julian; Banerjee, Varsha

2016-09-01

Aggregates of magnetic nanoparticles (MNPs) exhibit unusual properties due to the interplay of small system size and long-range dipole-dipole interactions. Using the micromagnetic simulation software oommf, we study the spin morphologies and heat dissipation in micron-size spherical assemblies of MNPs. In particular, we examine the sensitivity of these properties to the dipolar strength, manipulated by the interparticle separation. As oommf is not designed for such a study, we have incorporated a novel scaling protocol for this purpose. We believe that it is essential for all studies where volume fractions are varied. Our main results are as follows: (i) Dense assemblies exhibit strong dipolar effects which yield local magnetic order in the core but not on the surface, where moments are randomly oriented. (ii) The probability distribution of ground-state energy exhibits a long high-energy tail for surface spins in contrast to small tails for the core spins. Consequently, there is a wide variation in the energy of surface spins but not the core spins. (iii) There is strong correlation between ground-state energy and heating properties on application of an oscillating magnetic field h (t ) =hocos2 π f t : the particles in the core heat uniformly, while those on the surface exhibit a wide range from cold to intensely hot. (iv) Specific choices of ho and f yield characteristic spatial heat distributions, e.g., hot surface and cold core, or vice versa. (iv) For all values of ho and f that we consider, heating was maximum at a specific volume fraction. These results are especially relevant in the context of contemporary applications such as hyperthermia and chemotherapy, and also for novel materials such as smart polymer beads and superspin glasses.

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

PubMed

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

2017-07-10

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

Impact of heating on sensory properties of French Protected Designation of Origin (PDO) blue cheeses. Relationships with physicochemical parameters.

PubMed

Bord, Cécile; Guerinon, Delphine; Lebecque, Annick

2016-07-01

The aim of this study was to measure the impact of heating on the sensory properties of blue-veined cheeses in order to characterise their sensory properties and to identify their specific sensory typology associated with physicochemical parameters. Sensory profiles were performed on a selection of Protected Designation of Origin (PDO) cheeses representing the four blue-veined cheese categories produced in the Massif Central (Fourme d'Ambert, Fourme de Montbrison, Bleu d'Auvergne and Bleu des Causses). At the same time, physicochemical parameters were measured in these cheeses. The relationship between these two sets of data was investigated. Four types of blue-veined cheeses displayed significantly different behaviour after heating and it is possible to discriminate these cheese categories through specific sensory attributes. Fourme d'Ambert and Bleu d'Auvergne exhibited useful culinary properties: they presented good meltability, stretchability and a weak oiling-off. However, basic tastes (salty, bitter and sour) are also sensory attributes which can distinguish heated blue cheeses. The relationship between the sensory and physicochemical data indicated a correlation suggesting that some of these sensory properties may be explained by certain physicochemical parameters of heated cheeses. © The Author(s) 2015.

Use of Satellite Data Assimilation to Infer Land Surface Thermal Inertia

NASA Technical Reports Server (NTRS)

Lapenta, William; McNider, Richard T.; Biazar, Arastoo; Suggs, Ron; Jedlovec, Gary; Dembek, Scott

2002-01-01

There are two important but observationally uncertain parameters in the grid averaged surface energy budgets of mesoscale models - surface moisture availability and thermal heat capacity. A technique has been successfully developed for assimilating Geostationary Operational Environmental Satellite (GOES) skin temperature tendencies during the mid-morning time frame to improve specification of surface moisture. In a new application of the technique, the use of satellite skin temperature tendencies in early evening is explored to improve specification of the surface thermal heat capacity. Together, these two satellite assimilation constraints have been shown to significantly improve the characterization of the surface energy budget of a mesoscale model on fine spatial scales. The GOES assimilation without the adjusted heat capacity was run operationally during the International H2O Project on a 12-km grid. This paper presents the results obtained when using both the moisture availability and heat capacity retrievals in concert. Preliminary results indicate that retrieved moisture availability alone improved the verification statistics of 2-meter temperature and dew point forecasts. Results from the 1.5 month long study period using the bulk heat capacity will be presented at the meeting.

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

PubMed

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

2015-01-01

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

Conceptual design study of geothermal district heating of a thirty-house subdivision in Elko, Nevada, using existing water-distribution systems, Phase III. Final technical report, October 1, 1979-September 30, 1980

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

Pitts, D.R.

1980-09-30

A conceptual design study for district heating of a 30-home subdivision located near the southeast extremity of the city of Elko, Nevada is presented. While a specific residential community was used in the study, the overall approach and methodologies are believed to be generally applicable for a large number of communities where low temperature geothermal fluid is available. The proposed district heating system utilizes moderate temperature, clean domestic water and existing community culinary water supply lines. The culinary water supply is heated by a moderate temperature geothermal source using a single heat exchanger at entry to the subdivision. The heatedmore » culinary water is then pumped to the houses in the community where energy is extracted by means of a water supplied heat pump. The use of heat pumps at the individual houses allows economic heating to result from supply of relatively cool water to the community, and this precludes the necessity of supplying objectionably hot water for normal household consumption use. Each heat pump unit is isolated from the consumptive water flow such that contamination of the water supply is avoided. The community water delivery system is modified to allow recirculation within the community, and very little rework of existing water lines is required. The entire system coefficient of performance (COP) for a typical year of heating is 3.36, exclusive of well pumping energy.« less

Complete Mie-Gruneisen Equation of State (update)

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

Menikoff, Ralph

2016-03-14

The Mie-Gruneisen equation of state (EOS) is frequently used in hydro simulations to model solids at high pressure (up to a few Mb). It is an incomplete EOS characterized by a Gr¨uneisen coefficient, = -V (@eP)V , that is a function of only V . Expressions are derived for isentropes and isotherms. This enables the extension to a complete EOS. Thermodynamic consistency requires that the specific heat is a function of a single scaled-temperature. A complete extension is uniquely determined by the temperature dependence of the specific heat at a fixed reference density. In addition we show that if themore » domain of the EOS extends to T = 0 and the specific heat vanishes on the zero isotherm then a function of only V is equivalent to a specific heat with a single temperature scale. If the EOS domain does not include the zero isotherm, then a specific heat with a single temperature scale leads to a generalization of the Mie-Gr¨uneisen EOS in which the pressure is linear in both the specific energy and the temperature. This corresponds to the limiting case of two temperature scales with one of the scales in the high temperature limit. Such an EOS has previously been used to model liquid nitromethane.« less

AC Calorimetry and Thermophysical Properties of Bulk Glass-Forming Metallic Liquids

NASA Technical Reports Server (NTRS)

Johnson, William L.

2000-01-01

Thermo-physical properties of two bulk metallic glass forming alloys, Ti34Zr11Cu47Ni8 (VIT 101) and Zr57Nb5Ni12.6Al10CU15.4 (VIT 106), were investigated in the stable and undercooled melt. Our investigation focused on measurements of the specific heat in the stable and undercooled liquid using the method of AC modulation calorimetry. The VIT 106 exhibited a maximum undercooling of 140 K in free radiative cooling. Specific heat measurements could be performed in stable melt down to an undercooling of 80 K. Analysis of the specific heat data indicate an anomaly near the equilibrium liquidus temperature. This anomaly is also observed in y the temperature dependencies of the external relaxation time, the specific volume, and the surface tension; it is tentatively attributed to a phase separation in the liquid state. The VIT 101 specimen exhibited a small undercooling of about 50 K. Specific heat measurements were performed in the stable and undercooled melt. These various results will be combined with ground based work such as the measurement of T-T-T curves in the electrostatic levitator and low temperature viscosity and specific heat measurements for modeling the nucleation kinetics of these alloys.

Monoclonal antibodies specific to heat-treated porcine blood.

PubMed

Raja Nhari, Raja Mohd Hafidz; Hamid, Muhajir; Rasli, Nurmunirah Mohamad; Omar, Abdul Rahman; El Sheikha, Aly Farag; Mustafa, Shuhaimi

2016-05-01

Porcine blood is potentially being utilized in food as a binder, gelling agent, emulsifier or colorant. However, for certain communities, the usage of animal blood in food is strictly prohibited owing to religious concerns and health reasons. This study reports the development of monoclonal antibodies (MAbs) against heat-treated soluble proteins (HSPs) of autoclaved porcine blood; characterization of MAbs against blood, non-blood and plasma from different animal species using qualitative indirect non-competitive enzyme-linked immunosorbent assay (ELISA); and immunoblotting of antigenic components in HSPs of porcine blood. Fifteen MAbs are specific to heat-treated and raw porcine blood and not cross-reacted with other animal blood and non-blood proteins (meat and non-meat). Twelve MAbs are specific to porcine plasma, while three MAbs specific to porcine plasma are cross-reacted with chicken plasma. Immunoblotting revealed antigenic protein bands (∼60, ∼85-100 and ∼250 kDa) in porcine blood and plasma recognized by the MAbs. Selection of MAbs that recognized 60 kDa HSPs of porcine blood and plasma as novel monoclonal antibodies would be useful for detection of porcine plasma in processed food using the immunoassay method. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Optimal Experiment Design for Thermal Characterization of Functionally Graded Materials

NASA Technical Reports Server (NTRS)

Cole, Kevin D.

2003-01-01

The purpose of the project was to investigate methods to accurately verify that designed , materials meet thermal specifications. The project involved heat transfer calculations and optimization studies, and no laboratory experiments were performed. One part of the research involved study of materials in which conduction heat transfer predominates. Results include techniques to choose among several experimental designs, and protocols for determining the optimum experimental conditions for determination of thermal properties. Metal foam materials were also studied in which both conduction and radiation heat transfer are present. Results of this work include procedures to optimize the design of experiments to accurately measure both conductive and radiative thermal properties. Detailed results in the form of three journal papers have been appended to this report.

An experimental and theoretical study of radiative extinction of diffusion flames

NASA Technical Reports Server (NTRS)

Wichman, Indrek S.; Atreya, A.

1994-01-01

Our work was primarily theoretical and numerical. We investigated the simplified modeling of heat losses in diffusion flames, then we 'ramped up' the level of complexity in each successive study until the final chapter discussed the general problem of soot/flame interaction. With regard to the specific objective of studying radiative extinction, we conclude that in the steady case a self-extinguishing zero-g flame is unlikely to occur. The soot volume fractions are too small. On the other hand, our work does provide rational means for assessing the mixture of chemical energy release and radiative heat release. It also provides clues for suitable 'tailoring' this balance. Thus heat fluxes to surrounding surfaces can be substantially increased by exploiting and modifying its sooting capability.

Male-Specific Coliphages as Indicators of Thermal Inactivation of Pathogens in Biosolids

PubMed Central

Nappier, Sharon P.; Aitken, Michael D.; Sobsey, Mark D.

2006-01-01

Male-specific (F+) coliphages have been proposed as a candidate indicator of fecal contamination and of virus reduction in waste treatment. However, in this and earlier work with a laboratory thermophilic anaerobic digester, a heat-resistant fraction of F+ coliphage populations indigenous to municipal wastewater and sludge was evident. We therefore isolated coliphages from municipal wastewater sludge and from biosolid samples after thermophilic anaerobic digestion to evaluate the susceptibility of specific groups to thermal inactivation. Similar numbers of F+ DNA and F+ RNA coliphages were found in untreated sludge, but the majority of isolates in digested biosolids were group I F+ RNA phages. Separate experiments on individual isolates at 53°C confirmed the apparent heat resistance of group I F+ RNA coliphages as well as the susceptibility of group III F+ RNA coliphages. Although few F+ DNA coliphages were recovered from the treated biosolid samples, thermal inactivation experiments indicated heat resistance similar to that of group I F+ RNA phages. Hence, F+ DNA coliphage reductions during thermophilic anaerobic digestion are probably related to mechanisms other than thermal inactivation. Further studies should focus on the group III F+ RNA coliphages as potential indicators of reductions of heat-resistant pathogens in thermal processes for sludge treatment. PMID:16597945

Thermal conductive properties of wood, green or dry, from -40° to +100° C: a literature review

Treesearch

H. Peter Steinhagen

1977-01-01

This literature review was conducted in connection with a study on heat transfer in frozen logs. A combination of data by two researchers on specific heat and thermal conductivity and diffusivity in the radial direction of wood, at various temperatures and moisture contents, is discussed and compared with data from other sources. Limited information found for the...

Capital cost estimate

NASA Technical Reports Server (NTRS)

1975-01-01

The capital cost estimate for the nuclear process heat source (NPHS) plant was made by: (1) using costs from the current commercial HTGR for electricity production as a base for items that are essentially the same and (2) development of new estimates for modified or new equipment that is specifically for the process heat application. Results are given in tabular form and cover the total investment required for each process temperature studied.

Is there a Biological Basis for Therapeutic Applications of Millimetre Waves and THz Waves?

NASA Astrophysics Data System (ADS)

Mattsson, Mats-Olof; Zeni, Olga; Simkó, Myrtill

2018-03-01

Millimetre wave (MMW) and THz wave (THz) applications are already employed in certain industrial and medical environments for non-destructive quality control, and medical imaging, diagnosis, and therapy, respectively. The aim of the present study is to investigate if published experimental studies (in vivo and in vitro) provide evidence for "non-thermal" biological effects of MMW and THz. Such effects would occur in absence of tissue heating and associated damage and are the ones that can be exploited for therapeutic medical use. The investigated studies provide some evidence for both MMW and THz that can influence biological systems in a manner that is not obviously driven by tissue heating. However, the number of relevant studies is very limited which severely limits the drawing of any far-reaching conclusions. Furthermore, the studies have not addressed specific interaction mechanisms and do not provide hints for future mechanistic studies. Also, the studies do not indicate any specific importance regarding power density levels, frequencies, or exposure duration. It is also unclear if any specific biological endpoints are especially sensitive. Any therapeutic potential of MMW or THz has to be evaluated based on future high-quality studies dealing with physical, bio-physical, and biological aspects that have specific health-related perspectives in mind.

An assessment of the impact of transition on advanced winged entry vehicle thermal protection system mass

NASA Technical Reports Server (NTRS)

Wurster, K. E.

1981-01-01

This study examines the impact of turbulent heating on thermal protection system (TPS) mass for advanced winged entry vehicles. Four basic systems are considered: insulative, metallic hot structures, metallic standoff, and hybrid systems. TPS sizings are performed using entry trajectories tailored specifically to the characteristics of each TPS concept under consideration. Comparisons are made between systems previously sized under the assumption of all laminar heating and those sized using a baseline estimate of transition and turbulent heating. The relative effect of different transition criteria on TPS mass requirements is also examined. Also investigated are entry trajectories tailored to alleviate turbulent heating. Results indicate the significant impact of turbulent heating on TPS mass and demonstrate the importance of both accurate transition criteria and entry trajectory tailoring.

Lower solar chromosphere-corona transition region. II - Wave pressure effects for a specific form of the heating function

NASA Technical Reports Server (NTRS)

Woods, D. Tod; Holzer, Thomas E.; Macgregor, Keith B.

1990-01-01

Lower transition region models with a balance between mechanical heating and radiative losses are expanded to include wave pressure effects. The models are used to study the simple damping length form of the heating function. The results are compared to the results obtained by Woods et al. (1990) for solutions in the lower transition region. The results suggest that a mixture of fast-mode and slow-mode waves may provide the appropriate heating mechanism in the lower transition region, with the decline in effective vertical wave speed caused by the refraction and eventual total reflection of the fast-mode wave resulting from the decreasing atmospheric density.

PCR-SSCP-based reconstruction of the original fungal flora of heat-processed meat products.

PubMed

Dorn-In, Samart; Hölzel, Christina S; Janke, Tobias; Schwaiger, Karin; Balsliemke, Joachim; Bauer, Johann

2013-03-01

Food processing of spoiled meat is prohibited by law, since it is a deception and does not comply with food safety aspects. In general, spoilage of meat is mostly caused by bacteria. However, a high contamination level of fungi could be also found in some meat or meat products with certain preserving conditions. In case that unhygienic meat is used to produce heat processed products, the microorganisms will be deactivated by heat, so that they cannot be detected by a standard cultivation method. Therefore, this study aimed to develop and apply a molecular biological method--polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP)--to reconstruct the original fungal flora of heat processed meat. Twenty primer pairs were tested for their specificity for fungal DNA. Since none of them fully complied with all study criteria (such as high specificity and sensitivity for fungal DNA; suitability of the products for PCR-SSCP) in the matrix "meat", we designed a new reverse primer, ITS5.8R. The primer pair ITS1/ITS5.8R amplified DNA from all tested fungal species, but not DNA from meat-producing animals or from ingredients of plant origin (spices). For the final test, 32 DNA bands in acrylamide gel from 15 meat products and 1 soy sauce were sequenced-all originating from fungal species, which were, in other studies, reported to contaminate meat e.g. Alternaria alternata, Aureobasidium pullulans, Candida rugosa, C. tropicalis, C. zeylanoides, Eurotium amstelodami and Pichia membranifaciens, and/or spices such as Botrytis aclada, Guignardia mangiferae, Itersonilia perplexans, Lasiodiplodia theobromae, Lewia infectoria, Neofusicoccum parvum and Pleospora herbarum. This confirms the suitability of PCR-SSCP to specifically detect fungal DNA in heat processed meat products, and thus provides an overview of fungal species contaminating raw material such as meat and spices. Copyright © 2013 Elsevier B.V. All rights reserved.

Field Heat Treatment Technician: Competency Profile. Apprenticeship and Industry Training. 20908.1

ERIC Educational Resources Information Center

Alberta Advanced Education and Technology, 2008

2008-01-01

The graduate of the Field Heat Treatment Technician apprenticeship program is a certified journeyperson who will be able: (1) use heat treatment equipment to apply heat to materials in order to change a material's properties; (2) Use their knowledge of the properties of heat, industry codes and specifications to determine how heat treatment will…

Unusual superconducting behavior in HfV2Ga4

NASA Astrophysics Data System (ADS)

Santos, F. B.; Correa, L. E.; de Lima, B. S.; Cigarroa, O. V.; da Luz, M. S.; Grant, T.; Fisk, Z.; Machado, A. J. S.

2018-04-01

Bulk superconductivity in HfV2Ga4 with critical temperature close to 4.1 K was determined via magnetic susceptibility, electrical resistivity and specific heat measurements. Both the upper and lower critical field dependence with reduced temperature (T /Tc) exhibit non-conventional behavior. The electronic component of specific heat shows a double-jump, the first close to Tc and the other close to 0.75Tc. We speculate about the nature of the douple jump observed in specific heat considering two plausable scenarios: bulk inhomogeneities and the existence of a second gap.

High specific heat superconducting composite

DOEpatents

Steyert, Jr., William A.

1979-01-01

A composite superconductor formed from a high specific heat ceramic such as gadolinium oxide or gadolinium-aluminum oxide and a conventional metal conductor such as copper or aluminum which are insolubly mixed together to provide adiabatic stability in a superconducting mode of operation. The addition of a few percent of insoluble gadolinium-aluminum oxide powder or gadolinium oxide powder to copper, increases the measured specific heat of the composite by one to two orders of magnitude below the 5.degree. K. level while maintaining the high thermal and electrical conductivity of the conventional metal conductor.

Enhanced specific heat jump in electron-doped CaMnO3: Spin ordering driven by charge separation

NASA Astrophysics Data System (ADS)

Moritomo, Y.; Machida, A.; Nishibori, E.; Takata, M.; Sakata, M.

2001-12-01

Temperature variation of the magnetic susceptibility χ, resistivity ρ, specific heat C, and lattice constants has been investigated in electron-doped CaMnO3. The parent CaMnO3 is an antiferromagnetic band insulator, and shows an insulator-metal crossover with electron doping, together with an enhanced ferromagnetic component. We have found an enhancement of the specific heat jump ΔC at the spin-ordering temperature Tspin and interpreted the enhancement in terms of the intrinsic charge separation.

Symmetric Anderson impurity model: Magnetic susceptibility, specific heat and Wilson ratio

NASA Astrophysics Data System (ADS)

Zalom, Peter; Pokorný, Vladislav; Janiš, Václav

2018-05-01

We extend the spin-polarized effective-interaction approximation of the parquet renormalization scheme from Refs. [1,2] applied on the symmetric Anderson model by adding the low-temperature asymptotics of the total energy and the specific heat. We calculate numerically the Wilson ratio and determine analytically its asymptotic value in the strong-coupling limit. We demonstrate in this way that the exponentially small Kondo scale from the strong-coupling regime emerges in qualitatively the same way in the spectral function, magnetic susceptibility and the specific heat.

Heat-related deaths in hot cities: estimates of human tolerance to high temperature thresholds.

PubMed

Harlan, Sharon L; Chowell, Gerardo; Yang, Shuo; Petitti, Diana B; Morales Butler, Emmanuel J; Ruddell, Benjamin L; Ruddell, Darren M

2014-03-20

In this study we characterized the relationship between temperature and mortality in central Arizona desert cities that have an extremely hot climate. Relationships between daily maximum apparent temperature (ATmax) and mortality for eight condition-specific causes and all-cause deaths were modeled for all residents and separately for males and females ages <65 and ≥ 65 during the months May-October for years 2000-2008. The most robust relationship was between ATmax on day of death and mortality from direct exposure to high environmental heat. For this condition-specific cause of death, the heat thresholds in all gender and age groups (ATmax = 90-97 °F; 32.2-36.1 °C) were below local median seasonal temperatures in the study period (ATmax = 99.5 °F; 37.5 °C). Heat threshold was defined as ATmax at which the mortality ratio begins an exponential upward trend. Thresholds were identified in younger and older females for cardiac disease/stroke mortality (ATmax = 106 and 108 °F; 41.1 and 42.2 °C) with a one-day lag. Thresholds were also identified for mortality from respiratory diseases in older people (ATmax = 109 °F; 42.8 °C) and for all-cause mortality in females (ATmax = 107 °F; 41.7 °C) and males <65 years (ATmax = 102 °F; 38.9 °C). Heat-related mortality in a region that has already made some adaptations to predictable periods of extremely high temperatures suggests that more extensive and targeted heat-adaptation plans for climate change are needed in cities worldwide.

49 CFR 179.220-11 - Postweld heat treatment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.220-11 Section 179... Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld heat treatment of the cylindrical portions of the outer shell to which the anchorage...

Improvement of fire-tube boilers calculation methods by the numerical modeling of combustion processes and heat transfer in the combustion chamber

NASA Astrophysics Data System (ADS)

Komarov, I. I.; Rostova, D. M.; Vegera, A. N.

2017-11-01

This paper presents the results of study on determination of degree and nature of influence of operating conditions of burner units and flare geometric parameters on the heat transfer in a combustion chamber of the fire-tube boilers. Change in values of the outlet gas temperature, the radiant and convective specific heat flow rate with appropriate modification of an expansion angle and a flare length was determined using Ansys CFX software package. Difference between values of total heat flow and bulk temperature of gases at the flue tube outlet calculated using the known methods for thermal calculation and defined during the mathematical simulation was determined. Shortcomings of used calculation methods based on the results of a study conducted were identified and areas for their improvement were outlined.

A gastrointestinal anti-infectious biotherapeutic agent: the heat-treated Lactobacillus LB

PubMed Central

Liévin-Le Moal, Vanessa

2016-01-01

Experimental in vitro and in vivo studies support the hypothesis that heat-treated, lyophilized Lactobacillus acidophilus LB cells and concentrated, neutralized spent culture medium conserve the variety of pharmacological, antimicrobial activities of the live probiotic strain against several infectious agents involved in well-established acute and persistent watery diarrhoea and gastritis. Heat-treated cells and heat-stable secreted molecules trigger multiple strain-specific activities explaining the therapeutic efficacy of L. acidophilus LB. This review discusses the current body of knowledge on the antimicrobial mechanisms of action exerted by L. acidophilus LB demonstrated in in vitro and in vivo experimental studies, and the evidence for the therapeutic efficacy of this anti-infectious biotherapeutic agent proved in randomized clinical trials for the treatment of acute and persistent watery diarrhoea associated with several intestinal infectious diseases in humans. PMID:26770268

Absence of a long-range ordered magnetic ground state in Pr3Rh4Sn13 studied through specific heat and inelastic neutron scattering

NASA Astrophysics Data System (ADS)

Nair, Harikrishnan S.; Ogunbunmi, Michael O.; Ghosh, S. K.; Adroja, D. T.; Koza, M. M.; Guidi, T.; Strydom, A. M.

2018-04-01

Signatures of absence of a long-range ordered magnetic ground state down to 0.36 K are observed in magnetic susceptibility, specific heat, thermal/electrical transport and inelastic neutron scattering data of the quasi-skutterudite compound Pr3Rh4Sn13 which crystallizes in the Yb3Rh4Sn13-type structure with a cage-like network of Sn atoms. In this structure, Pr3+ occupies a lattice site with D 2d point symmetry having a ninefold degeneracy corresponding to J  =  4. The magnetic susceptibility of Pr3Rh4Sn13 shows only a weak temperature dependence below 10 K otherwise remaining paramagnetic-like in the range, 10 K-300 K. From the inelastic neutron scattering intensity of Pr3Rh4Sn13 recorded at different temperatures, we identify excitations at 4.5(7) K, 5.42(6) K, 10.77(5) K, 27.27(5) K, 192.28(4) K and 308.33(3) K through a careful peak analysis. However, no signatures of long-range magnetic order are observed in the neutron data down to 1.5 K, which is also confirmed by the specific heat data down to 0.36 K. A broad Schottky-like peak is recovered for the magnetic part of the specific heat, C 4f, which suggests the role of crystal electric fields of Pr3+ . A crystalline electric field model consisting of 7 levels was applied to C 4f which leads to the estimation of energy levels at 4.48(2) K, 6.94(4) K, 11.23(8) K, 27.01(5) K, 193.12(6) K and 367.30(2) K. The CEF energy levels estimated from the heat capacity analysis are in close agreement with the excitation energies seen in the neutron data. The Sommerfeld coefficient estimated from the analysis of magnetic specific heat is γ = 761(6) mJ K-2 mol-Pr which suggests the formation of heavy itinerant quasi-particles in Pr3Rh4Sn13. Combining inelastic neutron scattering results, analysis of the specific heat data down to 0.36 K, magnetic susceptibility and, electrical and thermal transport, we establish the absence of long-range ordered magnetic ground state in Pr3Rh4Sn13.

40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

Code of Federal Regulations, 2010 CFR

2010-07-01

... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass emissions. (a) Coal-fired units. The owner or operator of a coal...

Heat, heat waves, and out-of-hospital cardiac arrest.

PubMed

Kang, Si-Hyuck; Oh, Il-Young; Heo, Jongbae; Lee, Hyewon; Kim, Jungeun; Lim, Woo-Hyun; Cho, Youngjin; Choi, Eue-Keun; Yi, Seung-Muk; Sang, Do Shin; Kim, Ho; Youn, Tae-Jin; Chae, In-Ho; Oh, Seil

2016-10-15

Cardiac arrest is one of the common presentations of cardiovascular disorders and a leading cause of death. There are limited data on the relationship between out-of-hospital cardiac arrest (OHCA) and ambient temperatures, specifically extreme heat. This study investigated how heat and heat waves affect the occurrence of OHCA. Seven major cities in Korea with more than 1 million residents were included in this study. A heat wave was defined as a daily mean temperature above the 98th percentile of the yearly distribution for at least two consecutive days. A total of 50,318 OHCAs of presumed cardiac origin were identified from the nationwide emergency medical service database between 2006 and 2013. Ambient temperature and OHCA had a J-shaped relationship with a trough at 28°C. Heat waves were shown to be associated with a 14-% increase in the risk of OHCA. Adverse effects were apparent from the beginning of each heat wave period and slightly increased during its continuation. Excess OHCA events during heat waves occurred between 3PM and 5PM. Subgroup analysis showed that those 65years or older were significantly more susceptible to heat waves. Ambient temperature and OHCA had a J-shaped relationship. The risk of OHCA was significantly increased with heat waves. Excess OHCA events primarily occurred during the afternoon when the temperature was high. We found that the elderly were more susceptible to the deleterious effects of heat waves. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Large-Eddy Simulations of Noise Generation in Supersonic Jets at Realistic Engine Temperatures

NASA Astrophysics Data System (ADS)

Liu, Junhui; Corrigan, Andrew; Kailasanath, K.; Taylor, Brian

2015-11-01

Large-eddy simulations (LES) have been carried out to investigate the noise generation in highly heated supersonic jets at temperatures similar to those observed in high-performance jet engine exhausts. It is found that the exhaust temperature of high-performance jet engines can range from 1000K at an intermediate power to above 2000K at a maximum afterburning power. In low-temperature jets, the effects of the variation of the specific heat ratio as well as the radial temperature profile near the nozzle exit are small and are ignored, but it is not clear whether those effects can be also ignored in highly heated jets. The impact of the variation of the specific heat ratio is assessed by comparing LES results using a variable specific heat ratio with those using a constant specific heat ratio. The impact on both the flow field and the noise distributions are investigated. Because the total temperature near the nozzle wall can be substantially lower than the nozzle total temperature either due to the heating loss through the nozzle wall or due to the cooling applied near the wall, this lower wall temperature may impact the temperature in the shear layer, and thus impact the noise generation. The impact of the radial temperature profile on the jet noise generation is investigated by comparing results of lower nozzle wall temperatures with those of the adiabatic wall condition.

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

NASA Technical Reports Server (NTRS)

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

1981-01-01

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

Study, optimization, and design of a laser heat engine. [for satellite applications

NASA Technical Reports Server (NTRS)

Taussig, R. T.; Cassady, P. E.; Zumdieck, J. F.

1978-01-01

Laser heat engine concepts, proposed for satellite applications, are analyzed to determine which engine concept best meets the requirements of high efficiency (50 percent or better), continuous operation in space using near-term technology. The analysis of laser heat engines includes the thermodynamic cycles, engine design, laser power sources, collector/concentrator optics, receiving windows, absorbers, working fluids, electricity generation, and heat rejection. Specific engine concepts, optimized according to thermal efficiency, are rated by their technological availability and scaling to higher powers. A near-term experimental demonstration of the laser heat engine concept appears feasible utilizing an Otto cycle powered by CO2 laser radiation coupled into the engine through a diamond window. Higher cycle temperatures, higher efficiencies, and scalability to larger sizes appear to be achievable from a laser heat engine design based on the Brayton cycle and powered by a CO laser.

Impact of Climate Change on Heat-Related Mortality in Jiangsu Province, China

NASA Technical Reports Server (NTRS)

Chen, Kai; Horton, Radley M.; Bader, Daniel A.; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L.

2017-01-01

A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate.

Impact of climate change on heat-related mortality in Jiangsu Province, China.

PubMed

Chen, Kai; Horton, Radley M; Bader, Daniel A; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L

2017-05-01

A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heat-Related Mortality Projections for Cardiovascular and Respiratory Disease Under the Changing Climate in Beijing, China

NASA Technical Reports Server (NTRS)

Li, Tiantian; Ban, Jie; Horton, Radley M.; Bader, Daniel A.; Huang, Ganlin; Sun, Qinghua; Kinney, Patrick L.

2015-01-01

Because heat-related health effects tend to become more serious at higher temperatures, there is an urgent need to determine the mortality projection of specific heat-sensitive diseases to provide more detailed information regarding the variation of the sensitivity of such diseases. In this study, the specific mortality of cardiovascular and respiratory disease in Beijing was initially projected under five different global-scale General Circulation Models (GCMs) and two Representative Concentration Pathways scenarios (RCPs) in the 2020s, 2050s, and 2080s compared to the 1980s. Multi-model ensembles indicated cardiovascular mortality could increase by an average percentage of 18.4 percent, 47.8 percent, and 69.0 percent in the 2020s, 2050s, and 2080s under RCP 4.5, respectively, and by 16.6 percent, 73.8 percent and 134 percent in different decades respectively, under RCP 8.5 compared to the baseline range. The same increasing pattern was also observed in respiratory mortality. The heat-related deaths under the RCP 8.5 scenario were found to reach a higher number and to increase more rapidly during the 21st century compared to the RCP4.5 scenario, especially in the 2050s and the 2080s. The projection results show potential trends in cause-specific mortality in the context of climate change, and provide support for public health interventions tailored to specific climate-related future health risks.

Estimation of transient heat flux density during the heat supply of a catalytic wall steam methane reformer

NASA Astrophysics Data System (ADS)

Settar, Abdelhakim; Abboudi, Saïd; Madani, Brahim; Nebbali, Rachid

2018-02-01

Due to the endothermic nature of the steam methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.

A cross-sectional, randomized cluster sample survey of household vulnerability to extreme heat among slum dwellers in ahmedabad, india.

PubMed

Tran, Kathy V; Azhar, Gulrez S; Nair, Rajesh; Knowlton, Kim; Jaiswal, Anjali; Sheffield, Perry; Mavalankar, Dileep; Hess, Jeremy

2013-06-18

Extreme heat is a significant public health concern in India; extreme heat hazards are projected to increase in frequency and severity with climate change. Few of the factors driving population heat vulnerability are documented, though poverty is a presumed risk factor. To facilitate public health preparedness, an assessment of factors affecting vulnerability among slum dwellers was conducted in summer 2011 in Ahmedabad, Gujarat, India. Indicators of heat exposure, susceptibility to heat illness, and adaptive capacity, all of which feed into heat vulnerability, was assessed through a cross-sectional household survey using randomized multistage cluster sampling. Associations between heat-related morbidity and vulnerability factors were identified using multivariate logistic regression with generalized estimating equations to account for clustering effects. Age, preexisting medical conditions, work location, and access to health information and resources were associated with self-reported heat illness. Several of these variables were unique to this study. As sociodemographics, occupational heat exposure, and access to resources were shown to increase vulnerability, future interventions (e.g., health education) might target specific populations among Ahmedabad urban slum dwellers to reduce vulnerability to extreme heat. Surveillance and evaluations of future interventions may also be worthwhile.

Intratumoral iron oxide nanoparticle hyperthermia and radiation cancer treatment

NASA Astrophysics Data System (ADS)

Hoopes, P. J.; Strawbridge, R. R.; Gibson, U. J.; Zeng, Q.; Pierce, Z. E.; Savellano, M.; Tate, J. A.; Ogden, J. A.; Baker, I.; Ivkov, R.; Foreman, A. R.

2007-02-01

The potential synergism and benefit of combined hyperthermia and radiation for cancer treatment is well established, but has yet to be optimized clinically. Specifically, the delivery of heat via external arrays /applicators or interstitial antennas has not demonstrated the spatial precision or specificity necessary to achieve appropriate a highly positive therapeutic ratio. Recently, antibody directed and possibly even non-antibody directed iron oxide nanoparticle hyperthermia has shown significant promise as a tumor treatment modality. Our studies are designed to determine the effects (safety and efficacy) of iron oxide nanoparticle hyperthermia and external beam radiation in a murine breast cancer model. Methods: MTG-B murine breast cancer cells (1 x 106) were implanted subcutaneous in 7 week-old female C3H/HeJ mice and grown to a treatment size of 150 mm3 +/- 50 mm3. Tumors were then injected locally with iron oxide nanoparticles and heated via an alternating magnetic field (AMF) generator operated at approximately 160 kHz and 400 - 550 Oe. Tumor growth was monitored daily using standard 3-D caliper measurement technique and formula. specific Mouse tumors were heated using a cooled, 36 mm diameter square copper tube induction coil which provided optimal heating in a 1 cm wide region in the center of the coil. Double dextran coated 80 nm iron oxide nanoparticles (Triton Biosystems) were used in all studies. Intra-tumor, peri-tumor and rectal (core body) temperatures were continually measured throughout the treatment period. Results: Preliminary in vivo nanoparticle-AMF hyperthermia (167 KHz and 400 or 550 Oe) studies demonstrated dose responsive cytotoxicity which enhanced the effects of external beam radiation. AMF associated eddy currents resulted in nonspecific temperature increases in exposed tissues which did not contain nanoparticles, however these effects were minor and not injurious to the mice. These studies also suggest that iron oxide nanoparticle hyperthermia is more effective than non-nanoparticle tumor heating techniques when similar thermal doses are applied. Initial electron and light microscopy studies of iron oxide nanoparticle and AMF exposed tumor cells show a rapid uptake of particles and acute cytotoxicity following AMF exposure.

Highly macroscopically degenerated single-point ground states as source of specific heat capacity anomalies in magnetic frustrated systems

NASA Astrophysics Data System (ADS)

Jurčišinová, E.; Jurčišin, M.

2018-04-01

Anomalies of the specific heat capacity are investigated in the framework of the exactly solvable antiferromagnetic spin- 1 / 2 Ising model in the external magnetic field on the geometrically frustrated tetrahedron recursive lattice. It is shown that the Schottky-type anomaly in the behavior of the specific heat capacity is related to the existence of unique highly macroscopically degenerated single-point ground states which are formed on the borders between neighboring plateau-like ground states. It is also shown that the very existence of these single-point ground states with large residual entropies predicts the appearance of another anomaly in the behavior of the specific heat capacity for low temperatures, namely, the field-induced double-peak structure, which exists, and should be observed experimentally, along with the Schottky-type anomaly in various frustrated magnetic system.

Thermal Diffusivity and Specific Heat Measurements of Titanium Potassium Perchlorate Titanium Subhydride Potassium Perchlorate 9013 Glass 7052 Glass SB-14 Glass and C-4000 Muscovite Mica Using the Flash Technique

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

Specht, Paul Elliott; Cooper, Marcia A.

The flash technique was used to measure the thermal diffusivity and specific heat of titanium potassium perchlorate (TKP) ignition powder (33wt% Ti - 67wt% KP) with Ventron sup- plied titanium particles, TKP ignition powder (33wt% Ti - 67wt% KP) with ATK supplied titanium particles, TKP output powder (41wt% Ti - 59wt% KP), and titanium subhydride potassium perchlorate (THKP) (33wt% TiH 1.65 - 67wt% KP) at 25°C. The influence of density and temperature on the thermal diffusivity and specific heat of TKP with Ventron supplied titanium particles was also investigated. Lastly, the thermal diffusivity and specific heats of 9013 glass, 7052more » glass, SB-14 glass, and C-4000 Muscovite mica are presented as a function of temperature up to 300° C.« less

Low-temperature specific heat of single-crystal Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10

NASA Astrophysics Data System (ADS)

Urbach, J. S.; Mitzi, D. B.; Kapitulnik, A.; Wei, J. Y. T.; Morris, D. E.

1989-06-01

We report specific-heat measurements from 2 to 15 K on single crystals of Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10 We find low-temperature deviations from the Debye law that can be attributed to spin-glass behavior of a small concentration of isolated impurity copper moments. At higher temperatures, we observe contributions to the specific heat that can be attributed to a soft-phonon mode, possibly associated with the superstructure in the Bi-O and Tl-O layers. From our single-crystal data, we conclude that the thallium- and bismuth-based copper oxide superconductors show no measurable linear term in the specific heat [γ(0)<=1 mJ/mole K2].

Calorimetry of a Bose–Einstein-condensed photon gas

PubMed Central

Damm, Tobias; Schmitt, Julian; Liang, Qi; Dung, David; Vewinger, Frank; Weitz, Martin; Klaers, Jan

2016-01-01

Phase transitions, as the condensation of a gas to a liquid, are often revealed by a discontinuous behaviour of thermodynamic quantities. For liquid helium, for example, a divergence of the specific heat signals the transition from the normal fluid to the superfluid state. Apart from liquid helium, determining the specific heat of a Bose gas has proven to be a challenging task, for example, for ultracold atomic Bose gases. Here we examine the thermodynamic behaviour of a trapped two-dimensional photon gas, a system that allows us to spectroscopically determine the specific heat and the entropy of a nearly ideal Bose gas from the classical high temperature to the Bose-condensed quantum regime. The critical behaviour at the phase transition is clearly revealed by a cusp singularity of the specific heat. Regarded as a test of quantum statistical mechanics, our results demonstrate a quantitative agreement with its predictions at the microscopic level. PMID:27090978

Quantum criticality at the superconductor-insulator transition revealed by specific heat measurements

PubMed Central

Poran, S.; Nguyen-Duc, T.; Auerbach, A.; Dupuis, N.; Frydman, A.; Bourgeois, Olivier

2017-01-01

The superconductor–insulator transition (SIT) is considered an excellent example of a quantum phase transition that is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low-energy fluctuations near quantum criticality may be experimentally detected by specific heat, cp, measurements. Here we use a unique highly sensitive experiment to measure cp of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature marking the onset of Cooper pairs formation. As the film thickness is tuned towards the SIT, is relatively unchanged, while the magnitude of the jump and low-temperature specific heat increase significantly. This behaviour is taken as the thermodynamic fingerprint of quantum criticality in the vicinity of a quantum phase transition. PMID:28224994

Quantum criticality at the superconductor-insulator transition revealed by specific heat measurements.

PubMed

Poran, S; Nguyen-Duc, T; Auerbach, A; Dupuis, N; Frydman, A; Bourgeois, Olivier

2017-02-22

The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition that is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low-energy fluctuations near quantum criticality may be experimentally detected by specific heat, c p , measurements. Here we use a unique highly sensitive experiment to measure c p of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature marking the onset of Cooper pairs formation. As the film thickness is tuned towards the SIT, is relatively unchanged, while the magnitude of the jump and low-temperature specific heat increase significantly. This behaviour is taken as the thermodynamic fingerprint of quantum criticality in the vicinity of a quantum phase transition.

Optimal irradiance for sintering of inkjet-printed Ag electrodes with a 532nm CW laser

NASA Astrophysics Data System (ADS)

Moon, Yoon Jae; Kang, Heuiseok; Kang, Kyungtae; Hwang, Jun Young; Moon, Seung Jae

2013-09-01

Industrial solar cell fabrication generally adopts printing process to deposit the front electrodes, which needs additional heat treatment after printing to enhance electrical conductivity. As a heating method, laser irradiation draws attention not only because of its special selectivity, but also because of its intense heating to achieve high electric conductivity which is essential to reduce ohmic loss of solar cells. In this study, variation of electric conductivity was examined with laser irradiation having various beam intensity. 532 nm continuous wave (CW) laser was irradiated on inkjet-printed silver lines on glass substrate and electrical resistance was measured in situ during the irradiation. The results demonstrate that electric conductivity varies nonlinearly with laser intensity, having minimum specific resistance of 4.1 x 10-8 Ωm at 529 W/cm2 irradiation. The results is interesting because the specific resistance achieved by the present laser irradiation was about 1.8 times lower than the best value obtainable by oven heating, even though it was still higher by 2.5 times than that of bulk silver. It is also demonstrated that the irradiation time, needed to finish sintering process, decreases with laser intensity. The numerical simulation of laser heating showed that the optimal heating temperature could be as high as 300 oC for laser sintering, while it was limited to 250 oC for oven sintering. The nonlinear response of sintering with heating intensity was discussed, based on the results of FESEM images and XRD analysis.

Space tug thermal control. [design criteria and specifications

NASA Technical Reports Server (NTRS)

1974-01-01

It was determined that space tug will require the capability to perform its mission within a broad range of thermal environments with currently planned mission durations of up to seven days, so an investigation was conducted to define a thermal design for the forward and intertank compartments and fuel cell heat rejection system that satisfies tug requirements for low inclination geosynchronous deploy and retrieve missions. Passive concepts were demonstrated analytically for both the forward and intertank compartments, and a worst case external heating environment was determined for use during the study. The thermal control system specifications and designs which resulted from the research are shown.

Thermal behaviour of GdCo1-xMnxO3 cobaltates

NASA Astrophysics Data System (ADS)

Thakur, Rasna; Thakur, Rajesh K.; Gaur, N. K.

2018-05-01

With the objective of exploring the unknown thermodynamic behavior of GdCo1-xMnxO3 family, we present here an investigation of the temperature-dependent (10K≤T≤1000K) thermodynamic properties of GdCo1-xMnxO3 (x=0.1 to 0.8). The specific heat of GdCoO3 with Mn doping in the perovskite structure at B-site has been studied by means of a Modified Rigid Ion Model (MRIM). The cohesive energy, specific heat (C), volume thermal expansion (α) and Gruneisen parameter (γ) of GdCo1-xMnxO3 compounds are also discussed.

Thermo physical Properties of Multiferroic Rare Earth Manganite GdMnO3

NASA Astrophysics Data System (ADS)

Choithrani, Renu; Gaur, N. K.

2008-04-01

We have investigated the thermophysical properties of multiferroic rare earth manganite GdMnO3 in the temperature range 15 K⩽T⩽300 K. We have applied interatomic potential to study the Specific heat (C) as a function of temperature. The calculated Specific heat values are closer to the available experimental data. At room temperature, the orthorhombic GdMnO3 phase is indicative of a strong Jahn-Teller distortion. In addition, we have reported the cohesive energy (φ), molecular force constant (f), compressibility (β), Restrahalen frequency (ν0), Debye temperature (ΘD) and Groneisen parameter (γ) at temperature 15 K⩽T⩽300 K.

Mechanisms of stress-induced cellular HSP72 release: implications for exercise-induced increases in extracellular HSP72.

PubMed

Lancaster, Graeme I; Febbraio, Mark A

2005-01-01

The heat shock proteins are a family of highly conserved proteins with critical roles in maintaining cellular homeostasis and in protecting the cell from stressful conditions. While the critical intracellular roles of heat shock proteins are undisputed, evidence suggests that the cell possess the necessary machinery to actively secrete specific heat shock proteins in response to cellular stress. In this review, we firstly discuss the evidence that physical exercise induces the release of heat shock protein 72 from specific tissues in humans. Importantly, it appears as though this release is the result of an active secretory process, as opposed to non-specific processes such as cell lysis. Next we discuss recent in vitro evidence that has identified a mechanistic basis for the observation that cellular stress induces the release of a specific subset of heat shock proteins. Importantly, while the classical protein secretory pathway does not seem to be involved in the stress-induced release of HSP72, we discuss the evidence that lipid-rafts and exosomes are important mediators of the stress-induced release of HSP72.

Estimating thermal diffusivity and specific heat from needle probe thermal conductivity data

USGS Publications Warehouse

Waite, W.F.; Gilbert, L.Y.; Winters, W.J.; Mason, D.H.

2006-01-01

Thermal diffusivity and specific heat can be estimated from thermal conductivity measurements made using a standard needle probe and a suitably high data acquisition rate. Thermal properties are calculated from the measured temperature change in a sample subjected to heating by a needle probe. Accurate thermal conductivity measurements are obtained from a linear fit to many tens or hundreds of temperature change data points. In contrast, thermal diffusivity calculations require a nonlinear fit to the measured temperature change occurring in the first few tenths of a second of the measurement, resulting in a lower accuracy than that obtained for thermal conductivity. Specific heat is calculated from the ratio of thermal conductivity to diffusivity, and thus can have an uncertainty no better than that of the diffusivity estimate. Our thermal conductivity measurements of ice Ih and of tetrahydrofuran (THF) hydrate, made using a 1.6 mm outer diameter needle probe and a data acquisition rate of 18.2 pointss, agree with published results. Our thermal diffusivity and specific heat results reproduce published results within 25% for ice Ih and 3% for THF hydrate. ?? 2006 American Institute of Physics.

Is it possible to make a diagnosis of raw, heated, and baked egg allergy in children using cutoffs? A systematic review.

PubMed

Calvani, Mauro; Arasi, Stefania; Bianchi, Annamaria; Caimmi, Davide; Cuomo, Barbara; Dondi, Arianna; Indirli, Giovanni Cosimo; La Grutta, Stefania; Panetta, Valentina; Verga, Maria Carmen

2015-09-01

The diagnosis of IgE-mediated egg allergy lies both on a compatible clinical history and on the results of skin prick tests (SPTs) and IgEs levels. Both tests have good sensitivity but low specificity. For this reason, oral food challenge (OFC) is the ultimate gold standard for the diagnosis. The aim of this study was to systematically review the literature in order to identify, analyze, and synthesize the predictive value of SPT and specific IgEs both to egg white and to main egg allergens and to review the cutoffs suggested in the literature. A total of 37 articles were included in this systematic review. Studies were grouped according to the degree of cooking of the egg used for OFC, age, and type of allergen used to perform the allergy workup. In children <2 years, raw egg allergy seems very likely when SPTs with egg white extract are ≥4 mm or specific IgEs are ≥1.7 kUA /l. In children ≥2 years, OFC could be avoided when SPTs with egg white extract are ≥10 mm or prick by prick with egg white is ≥14 mm or specific IgE is ≥7.3 kUA /l. Likewise, heated egg allergy can be diagnosed if SPTs with egg white extract are >5 and >11 mm in children <2 and ≥2 years, respectively. Further and better-designed studies are needed to determine the remaining diagnostic cutoff of specific IgE and SPT for heated and baked egg allergy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exertional Heat Illnesses and Environmental Conditions During High School Football Practices.

PubMed

Tripp, Brady L; Eberman, Lindsey E; Smith, Michael Seth

2015-10-01

Guidelines for preventing exertional heat illnesses (EHIs) during extreme heat stress should be specific to regional environments, age, and sport and should be based on evidence of reducing the risk. Each year in the United States, over 1 million high school football players practice in the August heat; however, no published data describe the incidence of EHIs in these athletes. To describe the environmental conditions and incidence of EHIs during high school football practices over a 3-month period. Descriptive epidemiology study. For a 3-month period (August-October), athletic trainers at 12 high schools in North Central Florida recorded the practice time and length, environmental conditions (wet-bulb globe temperature), and incidences of EHIs in varsity football athletes. Athletes suffered 57 total EHIs during 29,759 athlete-exposures (AEs) for the 3-month data collection period (rate = 1.92/1000 AEs). August accounted for the majority of all EHIs, with 82.5% (47/57) and the highest rate (4.35/1000 AEs). Of total heat illnesses, heat cramps accounted for 70.2% (40/57), heat exhaustion 22.8% (13/57), and heat syncope 7.0% (4/57). The odds ratio indicated that athletes in August practices that lasted longer than the recommended 3 hours were 9.84 times more likely to suffer a heat illness than those in practices lasting ≤3 hours. The highest rate of EHIs was during August. Practices in August that exceeded the recommended 3 hours were associated with a greater risk of heat illnesses. The overall rate of EHIs was lower for the high school football athletes observed in the study compared with that reported for collegiate football athletes in the region. The low rates of EHIs recorded suggest that the prevention guidelines employed by sports medicine teams are appropriate for the region and population. Team physicians and athletic trainers should employ evidence-based, region- and population-specific EHI prevention guidelines. Sports medicine teams, coaches, and athletes should be aware of the increased risk of EHIs during August practices and the risk of prolonged practices during August. © 2015 The Author(s).

Preliminary analysis of aircraft fuel systems for use with broadened specification jet fuels

NASA Technical Reports Server (NTRS)

Pasion, A. J.; Thomas, I.

1977-01-01

An analytical study was conducted on the use of broadened specification hydrocarbon fuels in present day aircraft. A short range Boeing 727 mission and three long range Boeing 747 missions were used as basis of calculation for one-day-per-year extreme values of fuel loading, airport ambient and altitude ambient temperatures with various seasonal and climatic conditions. Four hypothetical fuels were selected; two high-vapor-pressure fuels with 35 kPa and 70 kPa RVP and two high-freezing-point fuels with -29 C and -18 C freezing points. In-flight fuel temperatures were predicted by Boeing's aircraft fuel tank thermal analyzer computer program. Boil-off rates were calculated for the high vapor pressure fuels and heating/insulation requirements for the high freezing point fuels were established. Possible minor and major heating system modifications were investigated with respect to heat output, performance and economic penalties for the high freezing point fuels.

The cavity heat pipe Stirling receiver for space solar dynamics

NASA Technical Reports Server (NTRS)

Kesseli, James B.; Lacy, Dovie E.

1989-01-01

The receiver/storage unit for the low-earth-orbiting Stirling system is discussed. The design, referred to as the cavity heat pipe (CHP), has been optimized for minimum specific mass and volume width. A specific version of this design at the 7-kWe level has been compared to the space station Brayton solar dynamic design. The space station design utilizes a eutectic mixture of LiF and CaF2. Using the same phase change material, the CHP has been shown to have a specific mass of 40 percent and a volume of 5 percent of that of the space station Brayton at the same power level. Additionally, it complements the free-piston Stirling engine in that it also maintains a relatively flat specific mass down to at least 1 kWe. The technical requirements, tradeoff studies, critical issues, and critical technology experiments are discussed.

Development, Fabrication, and Testing of a Liquid/Liquid Microchannel Heat Exchanger for Constellation Spacecrafts

NASA Technical Reports Server (NTRS)

Hawkins-Reynolds, Ebony; Le,Hung; Stephans, Ryan A.

2009-01-01

Minimizing mass and volume is critically important for space hardware. Microchannel technology can be used to decrease both of these parameters for heat exchangers. Working in concert with NASA, Pacific Northwest National Laboratories (PNNL) has developed a microchannel liquid/liquid heat exchanger that has resulted in significant mass and volume savings. The microchannel heat exchanger delivers these improvements without sacrificing thermal and pressure drop performance. A conventional heat exchanger has been tested and the performance of it recorded to compare it to the microchannel heat exchanger that PNNL has fabricated. The microchannel heat exchanger was designed to meet all of the requirements of the baseline heat exchanger, while reducing the heat exchanger mass and volume. The baseline heat exchanger was designed to have an transfer approximately 3.1 kW for a specific set of inlet conditions. The baseline heat exchanger mass was 2.7 kg while the microchannel mass was only 2.0 kg. More impressive, however, was the volumetric savings associated with the microchannel heat exchanger. The microchannel heat exchanger was an order of magnitude smaller than the baseline heat exchanger (2180cm3 vs. 311 cm3). This paper will describe the test apparatus designed to complete performance tests for both heat exchangers. Also described in this paper will be the performance specifications for the microchannel heat exchanger and how they compare to the baseline heat exchanger.

An experimental investigation devoted to determine heat transfer characteristics in a radiant ceiling heating system

NASA Astrophysics Data System (ADS)

Koca, Aliihsan; Acikgoz, Ozgen; Çebi, Alican; Çetin, Gürsel; Dalkilic, Ahmet Selim; Wongwises, Somchai

2018-02-01

Investigations on heated ceiling method can be considered as a new research area in comparison to the common wall heating-cooling and cooled ceiling methods. In this work, heat transfer characteristics of a heated radiant ceiling system was investigated experimentally. There were different configurations for a single room design in order to determine the convective and radiative heat transfer rates. Almost all details on the arrangement of the test chamber, hydraulic circuit and radiant panels, the measurement equipment and experimental method including uncertainty analysis were revealed in detail indicating specific international standards. Total heat transfer amount from the panels were calculated as the sum of radiation to the unheated surfaces, convection to the air, and conduction heat loss from the backside of the panels. Integral expression of the view factors was calculated by means of the numerical evaluations using Matlab code. By means of this experimental chamber, the radiative, convective and total heat-transfer coefficient values along with the heat flux values provided from the ceiling to the unheated surrounding surfaces have been calculated. Moreover, the details of 28 different experimental case study measurements from the experimental chamber including the convective, radiative and total heat flux, and heat output results are given in a Table for other researchers to validate their theoretical models and empirical correlations.

Sewage sludge drying by energy recovery from OFMSW composting: Preliminary feasibility evaluation

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

Rada, Elena Cristina; Ragazzi, Marco; Villotti, Stefano

2014-05-01

Highlights: • The aim is to support the drying of sewage sludge, using a solar greenhouse. • The system allows the exploitation of heat available from OFMSW aerobic process. • Another aim is to face the problem of OFMSW treatment, in particular food waste. • Energy and mass balances are presented for a case study. - Abstract: In this paper an original energy recovery method from composting is analyzed. The integrated system exploits the heat available from the aerobic biochemical process in order to support the drying of sewage sludge, using a specific solar greenhouse. The aim is to tacklemore » the problem of organic waste treatment, with specific regard to food waste. This is done by optimizing the energy consumption of the aerobic process of composting, using the heat produced to solve a second important waste management problem such as the sewage waste treatment. Energy and mass balances are presented in a preliminary feasibility study. Referring to a composting plant with a capacity of 15,000 t/y of food waste, the estimation of the power from recovered heat for the entire plant resulted about 42 kW. The results demonstrated that the energy recoverable can cover part of the heat necessary for the treatment of sludge generated by the population served by the composting plant (in terms of food waste and green waste collection). The addition of a renewable source such as solar energy could cover the residual energy demand. The approach is presented in detail in order for it to be replicated in other case studies or at full scale applications.« less

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

PubMed

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

2017-01-01

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

Influence of porosity on artificial deterioration of marble and limestone by heating

NASA Astrophysics Data System (ADS)

Sassoni, Enrico; Franzoni, Elisa

2014-06-01

Testing of stone consolidants to be used on-site, as well as research on new consolidating products, requires suitable stone samples, with deteriorated but still uniform and controllable characteristics. Therefore, a new methodology to artificially deteriorate stone samples by heating, exploiting the anisotropic thermal deformation of calcite crystals, has recently been proposed. In this study, the heating effects on a variety of lithotypes was evaluated and the influence of porosity in determining the actual heating effectiveness was specifically investigated. One marble and four limestones, having comparable calcite amounts but very different porosity, were heated at 400 °C for 1 hour. A systematic comparison between porosity, pore size distribution, water absorption, sorptivity and ultrasonic pulse velocity of unheated and heated samples was performed. The results of the study show that the initial stone porosity plays a very important role, as the modifications in microstructural, physical and mechanical properties are way less pronounced for increasing porosity. Heating was thus confirmed as a very promising artificial deterioration method, whose effectiveness in producing alterations that suitably resemble those actually experienced in the field depends on the initial porosity of the stone to be treated.

Temporal Changes in Mortality Related to Extreme Temperatures for 15 Cities in Northeast Asia: Adaptation to Heat and Maladaptation to Cold.

PubMed

Chung, Yeonseung; Noh, Heesang; Honda, Yasushi; Hashizume, Masahiro; Bell, Michelle L; Guo, Yue-Liang Leon; Kim, Ho

2017-05-15

Understanding how the temperature-mortality association worldwide changes over time is crucial to addressing questions of human adaptation under climate change. Previous studies investigated the temporal changes in the association over a few discrete time frames or assumed a linear change. Also, most studies focused on attenuation of heat-related mortality and studied the United States or Europe. This research examined continuous temporal changes (potentially nonlinear) in mortality related to extreme temperature (both heat and cold) for 15 cities in Northeast Asia (1972-2009). We used a generalized linear model with splines to simultaneously capture 2 types of nonlinearity: nonlinear association between temperature and mortality and nonlinear change over time in the association. We combined city-specific results to generate country-specific results using Bayesian hierarchical modeling. Cold-related mortality remained roughly constant over decades and slightly increased in the late 2000s, with a larger increase for cardiorespiratory deaths than for deaths from other causes. Heat-related mortality rates have decreased continuously over time, with more substantial decrease in earlier decades, for older populations and for cardiorespiratory deaths. Our findings suggest that future assessment of health effects of climate change should account for the continuous changes in temperature-related health risk and variations by factors such as age, cause of death, and location. © Crown copyright 2017.

Solar-assisted gas-energy water-heating feasibility for apartments

NASA Technical Reports Server (NTRS)

Davis, E. S.

1975-01-01

Studies of residential energy use, solar-energy technology for buildings, and the requirements for implementing technology in the housing industry led to a project to develop a solar water heater for apartments. A design study for a specific apartment was used to establish a solar water-heater cost model which is based on plumbing contractor bids and manufacturer estimates. The cost model was used to size the system to minimize the annualized cost of hot water. The annualized cost of solar-assisted gas-energy water heating is found to be less expensive than electric water heating but more expensive than gas water heating. The feasibility of a natural gas utility supplying the auxiliary fuel is evaluated. It is estimated that gas-utilizing companies will find it profitable to offer solar water heating as part of a total energy service option or on a lease basis when the price of new base-load supplies of natural gas reaches $2.50-$3.00 per million Btu.

Anomalous physical properties of Heusler-type Co2Cr (Ga,Si) alloys and thermodynamic study on reentrant martensitic transformation

NASA Astrophysics Data System (ADS)

Xu, Xiao; Nagasako, Makoto; Kataoka, Mitsuo; Umetsu, Rie Y.; Omori, Toshihiro; Kanomata, Takeshi; Kainuma, Ryosuke

2015-03-01

Electronic, magnetic, and thermodynamic properties of Co2Cr(Ga,Si) -based shape-memory alloys, which exhibit reentrant martensitic transformation (RMT) behavior, were studied experimentally. For electric resistivity (ER), an inverse (semiconductor-like) temperature dependence in the parent phase was found, along with anomalous behavior below its Curie temperature. A pseudobinary phase diagram was determined, which gives a "martensite loop" clearly showing the reentrant behavior. Differential scanning calorimetry and specific-heat measurements were used to derive the entropy change Δ S between martensite and parent phases. The temperature dependence of the derived Δ S was analyzed thermodynamically to confirm the appearances of both the RMT and normal martensitic transformation. Detailed studies on the specific heat in martensite and parent phases at low temperatures were also conducted.

Cause-specific risk of hospital admission related to extreme heat in older adults.

PubMed

Bobb, Jennifer F; Obermeyer, Ziad; Wang, Yun; Dominici, Francesca

Heat exposure is known to have a complex set of physiological effects on multiple organ systems, but current understanding of the health effects is mostly based on studies investigating a small number of prespecified health outcomes such as cardiovascular and respiratory diseases. To identify possible causes of hospital admissions during extreme heat events and to estimate their risks using historical data. Matched analysis of time series data describing daily hospital admissions of Medicare enrollees (23.7 million fee-for-service beneficiaries [aged ≥65 years] per year; 85% of all Medicare enrollees) for the period 1999 to 2010 in 1943 counties in the United States with at least 5 summers of near-complete (>95%) daily temperature data. Heat wave periods, defined as 2 or more consecutive days with temperatures exceeding the 99th percentile of county-specific daily temperatures, matched to non-heat wave periods by county and week. Daily cause-specific hospitalization rates by principal discharge diagnosis codes, grouped into 283 disease categories using a validated approach. Risks of hospitalization for fluid and electrolyte disorders, renal failure, urinary tract infection, septicemia, and heat stroke were statistically significantly higher on heat wave days relative to matched non-heat wave days, but risk of hospitalization for congestive heart failure was lower (P < .05). Relative risks for these disease groups were 1.18 (95% CI, 1.12-1.25) for fluid and electrolyte disorders, 1.14 (95% CI, 1.06-1.23) for renal failure, 1.10 (95% CI, 1.04-1.16) for urinary tract infections, 1.06 (95% CI, 1.00-1.11) for septicemia, and 2.54 (95% CI, 2.14-3.01) for heat stroke. Absolute risk differences were 0.34 (95% CI, 0.22-0.46) excess admissions per 100,000 individuals at risk for fluid and electrolyte disorders, 0.25 (95% CI, 0.12-0.39) for renal failure, 0.24 (95% CI, 0.09-0.39) for urinary tract infections, 0.21 (95% CI, 0.01-0.41) for septicemia, and 0.16 (95% CI, 0.10-0.22) for heat stroke. For fluid and electrolyte disorders and heat stroke, the risk of hospitalization increased during more intense and longer-lasting heat wave periods (P < .05). Risks were generally highest on the heat wave day but remained elevated for up to 5 subsequent days. Among older adults, periods of extreme heat were associated with increased risk of hospitalization for fluid and electrolyte disorders, renal failure, urinary tract infection, septicemia, and heat stroke. However, the absolute risk increase was small and of uncertain clinical importance.

Cause-Specific Risk of Hospital Admission Related to Extreme Heat in Older Adults

PubMed Central

Bobb, Jennifer F.; Obermeyer, Ziad; Wang, Yun; Dominici, Francesca

2015-01-01

IMPORTANCE Heat exposure is known to have a complex set of physiological effects on multiple organ systems, but current understanding of the health effects is mostly based on studies investigating a small number of prespecified health outcomes such as cardiovascular and respiratory diseases. OBJECTIVES To identify possible causes of hospital admissions during extreme heat events and to estimate their risks using historical data. DESIGN, SETTING, AND POPULATION Matched analysis of time series data describing daily hospital admissions of Medicare enrollees (23.7 million fee-for-service beneficiaries [aged ≥65 years] per year; 85% of all Medicare enrollees) for the period 1999 to 2010 in 1943 counties in the United States with at least 5 summers of near-complete (>95%) daily temperature data. EXPOSURES Heat wave periods, defined as 2 or more consecutive days with temperatures exceeding the 99th percentile of county-specific daily temperatures, matched to non–heat wave periods by county and week. MAIN OUTCOMES AND MEASURES Daily cause-specific hospitalization rates by principal discharge diagnosis codes, grouped into 283 disease categories using a validated approach. RESULTS Risks of hospitalization for fluid and electrolyte disorders, renal failure, urinary tract infection, septicemia, and heat stroke were statistically significantly higher on heat wave days relative to matched non–heat wave days, but risk of hospitalization for congestive heart failure was lower (P < .05). Relative risks for these disease groups were 1.18 (95% CI, 1.12–1.25) for fluid and electrolyte disorders, 1.14 (95% CI, 1.06–1.23) for renal failure, 1.10 (95% CI, 1.04–1.16) for urinary tract infections, 1.06 (95% CI, 1.00–1.11) for septicemia, and 2.54 (95% CI, 2.14–3.01) for heat stroke. Absolute risk differences were 0.34 (95% CI, 0.22–0.46) excess admissions per 100 000 individuals at risk for fluid and electrolyte disorders, 0.25 (95% CI, 0.12–0.39) for renal failure, 0.24 (95% CI, 0.09–0.39) for urinary tract infections, 0.21 (95% CI, 0.01–0.41) for septicemia, and 0.16 (95% CI, 0.10–0.22) for heat stroke. For fluid and electrolyte disorders and heat stroke, the risk of hospitalization increased during more intense and longer-lasting heat wave periods (P < .05). Risks were generally highest on the heat wave day but remained elevated for up to 5 subsequent days. CONCLUSIONS AND RELEVANCE Among older adults, periods of extreme heat were associated with increased risk of hospitalization for fluid and electrolyte disorders, renal failure, urinary tract infection, septicemia, and heat stroke. However, the absolute risk increase was small and of uncertain clinical importance. PMID:25536257

Phase transition in lithium ammonium sulphate doped with cesium metal ions

NASA Astrophysics Data System (ADS)

Gaafar, M.; Kassem, M. E.; Kandil, S. H.

2000-07-01

Effects of doped cesium (C s+) metal ions (with different molar ratios n) on the phase transition of lithium ammonium sulphate LiNH 4SO 4 system have been studied by measuring the specific heat Cp( T) of the doped systems in the temperature range from 400 to 480 K. The study shows a peculiar phase transition of the pure system ( n=0) characterized by double distinct peaks, changed to a single sharp and narrow one as a result of the doping process. The measurements exhibit different effects of enhanced molar ratios of dopants on the phase transition behaviour of this system. At low dopant content ( n≤3%), the excess specific heat (Δ Cp) max at the transition temperature T1 decreases till a minimum value at n=0.8%, then it increases gradually. In this case, Δ Cp( T) behaviour is varied quantitatively and not modified. Enhanced dopant content ( n>3%) has a pronounced effect on the critical behaviour, which is significantly changed and considerably modified relative to the pure system. In addition, broadening of the critical temperature region, and decrease of (Δ Cp) max associated with changes of the Landau expansion coefficients are obtained and discussed. The study deals with the contribution of the thermally excited dipoles to the specific heat in the ferroelectric region and shows that their energy depends on doping.

Physical and thermal properties of mud-dominant sediment from the Joetsu Basin in the eastern margin of the Japan Sea

NASA Astrophysics Data System (ADS)

Goto, Shusaku; Yamano, Makoto; Morita, Sumito; Kanamatsu, Toshiya; Hachikubo, Akihiro; Kataoka, Satsuki; Tanahashi, Manabu; Matsumoto, Ryo

2017-12-01

Physical properties (bulk density and porosity) and thermal properties (thermal conductivity, heat capacity, specific heat, and thermal diffusivity) of sediment are crucial parameters for basin modeling. We measured these physical and thermal properties for mud-dominant sediment recovered from the Joetsu Basin, in the eastern margin of the Japan Sea. To determine thermal conductivity, heat capacity, and thermal diffusivity, the dual-needle probe method was applied. Grain density and grain thermal properties for the mud-dominant sediment were estimated from the measured physical and thermal properties by applying existing models of physical and thermal properties of sediment. We suggest that the grain density, grain thermal conductivity, and grain thermal diffusivity depend on the sediment mineral composition. Conversely, the grain heat capacity and grain specific heat showed hardly any dependency on the mineral composition. We propose empirical formulae for the relationships between: thermal diffusivity and thermal conductivity, and heat capacity and thermal conductivity for the sediment in the Joetsu Basin. These relationships are different from those for mud-dominant sediment in the eastern flank of the Juan de Fuca Ridge presented in previous work, suggesting a difference in mineral composition, probably mainly in the amount of quartz, between the sediments in that area and the Joetsu Basin. Similar studies in several areas of sediments with various mineral compositions would enhance knowledge of the influence of mineral composition.

Melting and solidification characteristics of a mixture of two types of latent heat storage material in a vessel

NASA Astrophysics Data System (ADS)

Yu, JikSu; Horibe, Akihiko; Haruki, Naoto; Machida, Akito; Kato, Masashi

2016-11-01

In this study, we investigated the fundamental melting and solidification characteristics of mannitol, erythritol, and their mixture (70 % by mass mannitol: 30 % by mass erythritol) as potential phase-change materials (PCMs) for latent heat thermal energy storage systems, specifically those pertaining to industrial waste heat, having temperatures in the range of 100-250 °C. The melting point of erythritol and mannitol, the melting peak temperature of their mixture, and latent heat were measured using differential scanning calorimetry. The thermal performance of the mannitol mixture was determined during melting and solidification processes, using a heat storage vessel with a pipe heat exchanger. Our results indicated phase-change (fusion) temperatures of 160 °C for mannitol and 113 and 150 °C for the mannitol mixture. Nondimensional correlation equations of the average heat transfer during the solidification process, as well as the temperature and velocity efficiencies of flowing silicon oil in the pipe and the phase-change material (PCM), were derived using several nondimensional parameters.

Microwave Technology--Applications in Chemical Synthesis

EPA Science Inventory

Microwave heating, being specific and instantaneous, is unique and has found a place for expeditious chemical syntheses. Specifically, the solvent-free reactions are convenient to perform and have advantages over the conventional heating protocols as summarized in the previous se...

Negative specific heat of a magnetically self-confined plasma torus

PubMed Central

Kiessling, Michael K.-H.; Neukirch, Thomas

2003-01-01

It is shown that the thermodynamic maximum-entropy principle predicts negative specific heat for a stationary, magnetically self-confined current-carrying plasma torus. Implications for the magnetic self-confinement of fusion plasma are considered. PMID:12576553

49 CFR 179.400-12 - Postweld heat treatment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Postweld heat treatment. 179.400-12 Section 179...-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not required. (b) The... postweld heat treated as prescribed in AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of...

49 CFR 179.400-12 - Postweld heat treatment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Postweld heat treatment. 179.400-12 Section 179...-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not required. (b) The... postweld heat treated as prescribed in AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of...

49 CFR 179.400-12 - Postweld heat treatment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Postweld heat treatment. 179.400-12 Section 179...-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not required. (b) The... postweld heat treated as prescribed in AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of...

49 CFR 179.400-12 - Postweld heat treatment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Postweld heat treatment. 179.400-12 Section 179...-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not required. (b) The... postweld heat treated as prescribed in AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of...

Heat treatment and false-positive heartworm antigen testing in ex vivo parasites and dogs naturally infected by Dirofilaria repens and Angiostrongylus vasorum.

PubMed

Venco, Luigi; Manzocchi, Simone; Genchi, Marco; Kramer, Laura H

2017-11-09

Heartworm antigen testing is considered sensitive and specific. Currently available tests are reported as detecting a glycoprotein found predominantly in the reproductive tract of the female worm and can reach specificity close to 100%. Main concerns regard sensitivity in the case of light infections, the presence of immature females or cases of all-male infections. Research and development have been aimed at increasing sensitivity. Recently, heat treatment of serum prior to antigen testing has been shown to result in an increase in positive antigen test results, presumably due to disruption of natural antigen-antibody complexes. Cross-reactions in dogs with both natural and experimental infections with Angiostrongylus vasorum and Spirocerca lupi have been reported, but cross-reactions with other helminths have not been extensively studied. In order to evaluate potential cross-reactivity with other canine and feline parasites, two studies were performed. Study 1: Live adults of Dirofilaria immitis, Dirofilaria repens, Toxocara canis, Toxocara cati, Dipylidium caninum, Taenia taeniaeformis and Mesocestoides spp. larvae were washed and incubated in tubes with saline solution. All worms were alive at the time of removal from the saline. Saline solutions containing excretory/secretory antigens were then tested for heartworm with six different, commercially available antigen tests. All results were evaluated blind by three of the authors. Study 2: Sera from dogs with natural infections by A. vasorum or D. repens, living in areas free of heartworm disease, were tested with the same tests before and after heat treatment (103 °C for 10 min). Results suggest that antigens detected by currently available tests are not specific for D. immitis. They may give positive results through detection of different parasites' antigens that are normally not released into the bloodstream or released in a low amount and/or bound to antibodies. Tests may even detect antigens released by male D. immitis adult worms. D. repens appears to release more detectable antigens than the other worms studied. Cross-reaction with A. vasorum and D. repens does occur in the field and could potentially occur with other helminths. Heat treatment decreases specificity by enhancing cross-reactivity.

Red River Waterway Thermal Studies. Report 2. Thermal Stress Analyses

DTIC Science & Technology

1991-12-01

stress relaxation, q. Shrinkage of the concrete, and . Thermal properties of the concrete including coefficient of thermal expansion , specific heat...Finite-Element Code 12. The thermal stress analyses in this investigation was performed using ABAQUS , a general-purpose, heat-transfer and structural...model (the UMAT 9 subroutine discussed below) may be incorporated as an external subroutine linked to the ABAQUS library. 14. In order to model the

Lunar ash flow with heat transfer.

NASA Technical Reports Server (NTRS)

Pai, S. I.; Hsieh, T.; O'Keefe, J. A.

1972-01-01

The most important heat-transfer process in the ash flow under consideration is heat convection. Besides the four important nondimensional parameters of isothermal ash flow (Pai et al., 1972), we have three additional important nondimensional parameters: the ratio of the specific heat of the gas, the ratio of the specific heat of the solid particles to that of gas, and the Prandtl number. We reexamine the one dimensional steady ash flow discussed by Pai et al. (1972) by including the effects of heat transfer. Numerical results for the pressure, temperature, density of the gas, velocities of gas and solid particles, and volume fraction of solid particles as function of altitude for various values of the Jeffreys number, initial velocity ratio, and two different gas species (steam and hydrogen) are presented.

Sewage sludge drying by energy recovery from OFMSW composting: preliminary feasibility evaluation.

PubMed

Rada, Elena Cristina; Ragazzi, Marco; Villotti, Stefano; Torretta, Vincenzo

2014-05-01

In this paper an original energy recovery method from composting is analyzed. The integrated system exploits the heat available from the aerobic biochemical process in order to support the drying of sewage sludge, using a specific solar greenhouse. The aim is to tackle the problem of organic waste treatment, with specific regard to food waste. This is done by optimizing the energy consumption of the aerobic process of composting, using the heat produced to solve a second important waste management problem such as the sewage waste treatment. Energy and mass balances are presented in a preliminary feasibility study. Referring to a composting plant with a capacity of 15,000 t/y of food waste, the estimation of the power from recovered heat for the entire plant resulted about 42 kW. The results demonstrated that the energy recoverable can cover part of the heat necessary for the treatment of sludge generated by the population served by the composting plant (in terms of food waste and green waste collection). The addition of a renewable source such as solar energy could cover the residual energy demand. The approach is presented in detail in order for it to be replicated in other case studies or at full scale applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Computer modeling of heat pipe performance

NASA Technical Reports Server (NTRS)

Peterson, G. P.

1983-01-01

A parametric study of the defining equations which govern the steady state operational characteristics of the Grumman monogroove dual passage heat pipe is presented. These defining equations are combined to develop a mathematical model which describes and predicts the operational and performance capabilities of a specific heat pipe given the necessary physical characteristics and working fluid. Included is a brief review of the current literature, a discussion of the governing equations, and a description of both the mathematical and computer model. Final results of preliminary test runs of the model are presented and compared with experimental tests on actual prototypes.

Thermally induced secondary atomization of droplet in an acoustic field

NASA Astrophysics Data System (ADS)

Basu, Saptarshi; Saha, Abhishek; Kumar, Ranganathan

2012-01-01

We study the thermal effects that lead to instability and break up in acoustically levitated vaporizing fuel droplets. For selective liquids, atomization occurs at the droplet equator under external heating. Short wavelength [Kelvin-Helmholtz (KH)] instability for diesel and bio-diesel droplets triggers this secondary atomization. Vapor pressure, latent heat, and specific heat govern the vaporization rate and temperature history, which affect the surface tension gradient and gas phase density, ultimately dictating the onset of KH instability. We develop a criterion based on Weber number to define a condition for the inception of secondary atomization.

Investigation of the influence of groundwater advection on energy extraction rates for sustainable borehole heat exchanger operation

NASA Astrophysics Data System (ADS)

Schelenz, Sophie; Dietrich, Peter; Vienken, Thomas

2016-04-01

A sustainable thermal exploitation of the shallow subsurface requires a precise understanding of all relevant heat transport processes. Currently, planning practice of shallow geothermal systems (especially for systems < 30 kW) focuses on conductive heat transport as the main energy source while the impact of groundwater flow as the driver for advective heat transport is neglected or strongly simplified. The presented study proves that those simplifications of complex geological and hydrogeological subsurface characteristics are insufficient for a precise evaluation of site-specific energy extraction rates. Based on synthetic model scenarios with varying subsurface conditions (groundwater flow velocity and aquifer thickness) the impact of advection on induced long term temperature changes in 5 and 10 m distance of the borehole heat exchanger is presented. Extending known investigations, this study enhances the evaluation of shallow geothermal energy extraction rates by considering conductive and advective heat transport under varying aquifer thicknesses. Further, it evaluates the impact of advection on installation lengths of the borehole heat exchanger to optimize the initial financial investment. Finally, an evaluation approach is presented that classifies relevant heat transport processes according to their Péclet number to enable a first quantitative assessment of the subsurface energy regime and recommend further investigation and planning procedures.

Fish in hot water: hypoxaemia does not trigger catecholamine mobilization during heat shock in rainbow trout (Oncorhynchus mykiss).

PubMed

Currie, S; Ahmady, E; Watters, M A; Perry, S F; Gilmour, K M

2013-06-01

Rainbow trout (Oncorhynchus mykiss) exposed to an acute heat shock (1 h at 25 °C after raising water temperature from 13 °C to 25 °C over 4 h) mount a significant catecholamine response. The present study investigated the proximate mechanisms underlying catecholamine mobilization. Trout exposed to heat shock in vivo exhibited a significant reduction in arterial O(2) tension, but arterial O(2) concentration was not affected by heat shock, nor was catecholamine release during heat shock prevented by prior and concomitant exposure to hyperoxia (to prevent the fall in arterial O(2) tension). Thus, catecholamine mobilization probably was not triggered by impaired blood O(2) transport. Heat-shocked trout also exhibited an elevation of arterial CO(2) tension coupled with a fall in arterial pH, but these factors are not expected to trigger catecholamine release. The changes in blood O(2) and CO(2) tension occurred despite a significant hyperventilatory response to heat shock. Future studies should investigate whether catecholamine mobilization during heat shock in rainbow trout is triggered by a specific effect of high temperature activating the sympathetic nervous system via a thermosensitive transient receptor potential channel. Copyright © 2013 Elsevier Inc. All rights reserved.

Calorimetric measurements on Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60}

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

Inaba, Akira; Miyazaki, Yuji; Michałowski, Paweł P.

2015-04-28

We show specific heat data for Na{sub 4}C{sub 60} and Li{sub 4}C{sub 60} in the range 0.4-350 K for samples characterized by Raman spectroscopy and X-ray diffraction. At high temperatures, the two different polymer structures have very similar specific heats both in absolute values and in general trend. The specific heat data are compared with data for undoped polymeric and pristine C{sub 60}. At high temperatures, a difference in specific heat between the intercalated and undoped C{sub 60} polymers of 100 J K{sup −1} mol{sup −1} is observed, in agreement with the Dulong-Petit law. At low temperatures, the specific heatmore » data for Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60} are modified by the stiffening of vibrational and librational molecular motion induced by the polymer bonds. The covalent twin bonds in Li{sub 4}C{sub 60} affect these motions to a somewhat higher degree than the single intermolecular bonds in Na{sub 4}C{sub 60}. Below 1 K, the specific heats of both materials become linear in temperature, as expected from the effective dimensionality of the structure. The contribution to the total specific heat from the inserted metal ions can be well described by Einstein functions with T{sub E} = 386 K for Li{sub 4}C{sub 60} and T{sub E} = 120 K for Na{sub 4}C{sub 60}, but for both materials we also observe a Schottky-type contribution corresponding to a first approximation to a two-level system with ΔE = 9.3 meV for Li{sub 4}C{sub 60} and 3.1 meV for Na{sub 4}C{sub 60}, probably associated with jumps between closely spaced energy levels inside “octahedral-type” ionic sites. Static magnetic fields up to 9 T had very small effects on the specific heat below 10 K.« less

Microwave-specific heating of crystalline species in nuclear waste glass

DOE PAGES

Christian, Jonathan H.; Fox, Kevin M.; Washington, Aaron L.

2016-08-03

Here, the microwave heating of a crystal-free and a partially trevorite-crystallized nuclear waste glass simulant was evaluated. Our results show that a 500-mg monolith of partially crystallized waste glass can be heated from room temperature to above 1600°C within 2 min using a single-mode, highly focused, 2.45 GHz microwave, operating at 300 W. Using X-ray diffraction measurements, we show that trevorite is no longer detectable after irradiation and thermal quenching. When a crystal-free analog of the same waste glass simulant composition was exposed to the same microwave radiation, it could not be heated above 450°C regardless of the heating time.more » The reduction in crystalline content achieved by selectively heating spinels in the presence of glass suggests that microwave-specific heating should be further explored as a technique for remediating crystal accumulation in a glass melt.« less

Thermion: Verification of a thermionic heat pipe in microgravity

NASA Technical Reports Server (NTRS)

1991-01-01

The design and development is examined of a small excore heat pipe thermionic space nuclear reactor power system (SEHPTR). The need was identified for an in-space flight demonstration of a solar powered, thermionic heat pipe element. A demonstration would examine its performance and verify its operation in microgravity. The design of a microsatellite based technology demonstration experiment is proposed to measure the effects of microgravity on the performance of an integrated thermionic heat pipe device in low earth orbit. The specific objectives are to verify the operation of the liquid metal heat pipe and the cesium reservior in the space environment. Two design configurations are described; THERMION-I and THERMION-II. THERMION-I is designed for a long lifetime study of the operations of the thermionic heat pipe element in low earth orbit. Heat input to the element is furnished by a large mirror which collects solar energy and focuses it into a cavity containing the heat pipe device. THERMION-II is a much simpler device which is used for short term operation. This experiment remains attached to the Delta II second stage and uses energy from 500 lb of alkaline batteries to supply heat energy to the heat pipe device.

STUDIES ON THE ANTIGENIC STRUCTURE OF SOME MAMMALIAN SPERMATOZOA

PubMed Central

Henle, Werner; Henle, Gertrude; Chambers, Leslie A.

1938-01-01

1. A method has been described for separation of heads and tails of mammalian spermatozoa. 2. By means of absorption technique applied to homologous spermatozoal sera, head-specific and tail-specific antigens could be demonstrated. Both are heat-labile. 3. A heat-stable antigen was found to be common to both heads and tails. This substance is species-specific. 4. Antibodies against the head- and tail-specific antigens led to two different types of agglutination as shown by the slide method. 5. Using heterologous antisera against spermatozoa three different cross-reacting antigens could be observed, two in the heads, one in the tails. 6. One of the head-antigens is not active in the native cell; it comes to action only after breaking the cell. Antibodies against this substance were not found in antisera against native bull spermatozoa but were formed when vibrated spermatozoa or heads were injected into rabbits. 7. The cross-reactions can be removed from an antiserum leaving the head- as well as the tail-specific reaction intact. PMID:19870792

Abiotic and Biotic Stressors Causing Equivalent Mortality Induce Highly Variable Transcriptional Responses in the Soybean Aphid

PubMed Central

Enders, Laramy S.; Bickel, Ryan D.; Brisson, Jennifer A.; Heng-Moss, Tiffany M.; Siegfried, Blair D.; Zera, Anthony J.; Miller, Nicholas J.

2014-01-01

Environmental stress affects basic organismal functioning and can cause physiological, developmental, and reproductive impairment. However, in many nonmodel organisms, the core molecular stress response remains poorly characterized and the extent to which stress-induced transcriptional changes differ across qualitatively different stress types is largely unexplored. The current study examines the molecular stress response of the soybean aphid (Aphis glycines) using RNA sequencing and compares transcriptional responses to multiple stressors (heat, starvation, and plant defenses) at a standardized stress level (27% adult mortality). Stress-induced transcriptional changes showed remarkable variation, with starvation, heat, and plant defensive stress altering the expression of 3985, 510, and 12 genes, respectively. Molecular responses showed little overlap across all three stressors. However, a common transcriptional stress response was identified under heat and starvation, involved with up-regulation of glycogen biosynthesis and molecular chaperones and down-regulation of bacterial endosymbiont cellular and insect cuticular components. Stressor-specific responses indicated heat affected expression of heat shock proteins and cuticular components, whereas starvation altered a diverse set of genes involved in primary metabolism, oxidative reductive processes, nucleosome and histone assembly, and the regulation of DNA repair and replication. Exposure to host plant defenses elicited the weakest response, of which half of the genes were of unknown function. This study highlights the need for standardizing stress levels when comparing across stress types and provides a basis for understanding the role of general vs. stressor specific molecular responses in aphids. PMID:25538100

Vibrational pumping and heating under SERS conditions: fact or myth?

PubMed

Le Ru, E C; Etchegoin, P G

2006-01-01

We address in this paper the long debated issue of the possibility of vibrational pumping under Surface Enhanced Raman Scattering (SERS) conditions, both theoretically and experimentally. We revisit with simple theoretical models the mechanisms of vibrational pumping and its relation to heating. This presentation provides a clear classification of the various regimes of heating/pumping, from simple global laser heating to selective pumping of a single vibrational mode. We also propose the possibility of extreme pumping driven by stimulated phonon emission, and we introduce and apply a new experimental technique to study these effects in SERS. Our method relies on correlations between Raman peak parameters, and cross-correlation for two Raman peaks. We find strong evidence for local and dynamical heating, but no convincing evidence for selective pumping under our specific experimental SERS conditions.

Effect of boundary heat flux on columnar formation in binary alloys: A phase-field study

NASA Astrophysics Data System (ADS)

Du, Lifei; Zhang, Peng; Yang, Shaomei; Chen, Jie; Du, Huiling

2018-02-01

A non-isothermal phase-field model was employed to simulate the columnar formation during rapid solidification in binary Ni-Cu alloy. Heat flux at different boundaries was applied to investigate the temperature gradient effect on the morphology, concentration and temperature distributions during directional solidifications. With the heat flux input/extraction from boundaries, coupling with latent heat release and initial temperature gradient, temperature distributions are significantly changed, leading to solute diffusion changes during the phase-transition. Thus, irregular columnar structures are formed during the directional solidification, and the concentration distribution in solid columnar arms could also be changed due to the different growing speeds and temperature distributions at the solid-liquid interfaces. Therefore, applying specific heat conditions at the solidifying boundaries could be an efficient way to control the microstructure during solidifications.

Reduction of fine particle emissions from wood combustion with optimized condensing heat exchangers.

PubMed

Gröhn, Arto; Suonmaa, Valtteri; Auvinen, Ari; Lehtinen, Kari E J; Jokiniemi, Jorma

2009-08-15

In this study, we designed and built a condensing heat exchanger capable of simultaneous fine particle emission reduction and waste heat recovery. The deposition mechanisms inside the heat exchanger prototype were maximized using a computer model which was later compared to actual measurements. The main deposition mechanisms were diffusio- and thermophoresis which have previously been examined in similar conditions only separately. The obtained removal efficiency in the experiments was measured in the total number concentration and ranged between 26 and 40% for the given pellet stove and the heat exchanger. Size distributions and number concentrations were measured with a TSI Fast mobility particle sizer (FMPS). The computer model predicts that there exists a specific upper limit for thermo- and diffusiophoretic deposition for each temperature and water vapor concentration in the flue gas.

7 CFR 1755.870 - RUS specification for terminating cables.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of conductor insulation deformation or adhesion between conductors, caused by adverse heat transfer... x Overall Percent Difference in Average x Failures Insulation Compression: Control Heat Age..., Standard Specification for Forced-Convection Laboratory Ovens for Electrical Insulation; ASTM D 2633-82...

7 CFR 1755.870 - RUS specification for terminating cables.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of conductor insulation deformation or adhesion between conductors, caused by adverse heat transfer... x Overall Percent Difference in Average x Failures Insulation Compression: Control Heat Age..., Standard Specification for Forced-Convection Laboratory Ovens for Electrical Insulation; ASTM D 2633-82...

7 CFR 1755.870 - RUS specification for terminating cables.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of conductor insulation deformation or adhesion between conductors, caused by adverse heat transfer... x Overall Percent Difference in Average x Failures Insulation Compression: Control Heat Age..., Standard Specification for Forced-Convection Laboratory Ovens for Electrical Insulation; ASTM D 2633-82...

49 CFR 179.201-5 - Postweld heat treatment and corrosion resistance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179... thereto must be postweld heat treated as a unit at the proper temperature except as indicated below. Tanks...

Temperature rise due to mechanical energy dissipation in undirectional thermoplastic composites(AS4/PEEK)

NASA Technical Reports Server (NTRS)

Georgious, I. T.; Sun, C. T.

1992-01-01

The history of temperature rise due to internal dissipation of mechanical energy in insulated off-axis uniaxial specimens of the unidirectional thermoplastic composite (AS4/PEEK) has been measured. The experiment reveals that the rate of temperature rise is a polynomial function of stress amplitude: It consists of a quadratic term and a sixth power term. This fact implies that the specific heat of the composite depends on the stretching its microstructure undergoes during deformation. The Einstein theory for specific heat is used to explain the dependence of the specific heat on the stretching of the microstructure.

Low temperature specific heat of charge ordered Pr_1-xCa_xMnO_3

NASA Astrophysics Data System (ADS)

Smolyaninova, V. N.; Biswas, Amlan; Zhang, X.; Greene, R. L.

2000-03-01

Mixed-valent perovskite manganese oxides at certain doping levels develope a real space ordering of Mn^3+ and Mn^4+ at low temperatures^1, which can be destroyed (``melted'') by the application of a modest magnetic field.^2 To better understand the low-temperature ground state and the physics of the ``melted'' charge-ordered state, the specific heat, resistivity and magnetization of charge-ordered Pr_1-xCa_xMnO3 were measured with and without magnetic field for single crystal and ceramic samples of different x. A large excess specific heat of nonmagnetic origin was found, similar to that found in La_0.5Ca_0.5MnO3 ^3. Significant changes in the specific heat associated with the ``melting'' of the charge ordering were observed in applied magnetic fields up to 9 T. Possible explanations for this anomalous specific heat and its magnetic field dependence will be discussed . ^*This work is supported in part by NSF MRSEC Grant at the University of Maryland. ^1S. Mori, C. H. Chen and S-W. Cheong, Nature 392, 473 (1998). ^2Y. Tomioka et al., Phys. Rev. Lett. 74, 5108 (1995). ^3V. N. Smolyaninova, K. Ghosh and R. L. Greene, Phys. Rev. B 58, R14 725 (1998).

Magnetic and thermodynamic properties of a ferromagnetic mixed-spin (1/2, 1, 3/2) three-layer film superlattice

NASA Astrophysics Data System (ADS)

Lv, Dan; Ma, Ye; Jiang, Wei; Si, Xiu-li; Gao, Wei-chun

2018-07-01

Using the Monte Carlo simulation, we have studied the magnetic and thermodynamic properties of a ferromagnetic three-layer film mixed-spin (1/2, 1, 3/2) system. We have discussed the influence of intralayer and interfacial exchange couplings, film thickness, magnetic atom concentration and temperature on the magnetization of the superlattice system, magnetic susceptibility, internal energy and specific heat of the system. The phase diagrams in various parameters planes are obtained. Loads of interesting magnetic behaviors have been found, such as double-peak and triple-peak phenomena in the susceptibility and specific heat curves as well as obvious finite size effects for small layer thickness. Through a comparison, there is qualitatively a good agreement between our results and those of other theoretical and experimental studies.

Lipid class and depth-specific thermal properties in the blubber of the short-finned pilot whale and the pygmy sperm whale.

PubMed

Bagge, Laura E; Koopman, Heather N; Rommel, Sentiel A; McLellan, William A; Pabst, D A

2012-12-15

Blubber, the specialized hypodermis of cetaceans, provides thermal insulation through the quantity and quality of lipids it contains. Quality refers to percent lipid content; however, not all lipids are the same. Certain deep-diving cetacean groups possess blubber with lipids - wax esters (WE) - that are not typically found in mammals, and the insulative quality of 'waxy' blubber is unknown. Our study explored the influence of lipid storage class - specifically WE in pygmy sperm whales (Kogia breviceps; N=7) and typical mammalian triacylglycerols in short-finned pilot whales (Globicephala macrorhynchus; N=7) - on blubber's thermal properties. Although the blubber of both species had similar total lipid contents, the thermal conductivity of G. macrorhynchus blubber (0.20±0.01 W m(-1) °C(-1)) was significantly higher than that of K. breviceps (0.15±0.01 W m(-1) °C(-1); P=0.0006). These results suggest that lipid class significantly influences the ability of blubber to resist heat flow. In addition, because the lipid content of blubber is known to be stratified, we measured its depth-specific thermal conductivities. In K. breviceps blubber, the depth-specific conductivity values tended to vary inversely with lipid content. In contrast, G. macrorhynchus blubber displayed unexpected depth-specific relationships between lipid content and conductivity, which suggests that temperature-dependent effects, such as melting, may be occurring. Differences in heat flux measurements across the depth of the blubber samples provide evidence that both species are capable of storing heat in their blubber. The function of blubber as an insulator is complex and may rely upon its lipid class, stratified composition and dynamic heat storage capabilities.

Transport thermal properties of LiTaO 3 pyroelectric sensor from 15 K to 400 K and its application to the study of critical behavior in EuCo 2As 2

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

Oleaga, A.; Shvalya, V.; Sefat, Athena Safa

2016-01-04

ac photopyroelectric calorimeters in the standard back configuration, where LiTaO 3 is one of the most popular materials to be used as a detector, are commonly used to study phase transitions in solids and liquids. In order to extract the specific heat of a studied sample, a good knowledge of the thermal effusivity of the sensor as a function of temperature is needed. This function has been obtained for the first time in the range 15 K to 400 K by independently measuring LiTaO 3 thermal diffusivity and specific heat and combining both of them to give thermal effusivity. Usingmore » this photopyroelectric setup and LiTaO 3 as sensor, we have carried out the study of the critical behavior of the antiferromagnetic ordering of the Eu 2+ spins in EuCo 2As 2 (a compound with similar structure as EuFe 2As 2, from which superconductors have been developed) at low temperature by measuring its specific heat. Furthermore, the critical parameters found for EuCo 2As 2 (α=–0.017,A +/A –=1.06) agree with the 3D-XY universality class, indicating that the spins present an in-plane arrangement for Eu 2+, in agreement with magnetic measurements in the literature.« less

AIR EMISSIONS FROM RESIDENTIAL HEATING: THE WOOD HEATING OPTION PUT INTO ENVIRONMENTAL PERSPECTIVE

EPA Science Inventory

The paper compares the national scale (rather than local) air quality impacts of the various residential space heating options. Specifically, it compares the relative contribution of the space heating options to fine particulate emissions, greenhouse gas emissions, and acid preci...

Mind the gap - Deriving a compatible user mental model of the home heating system to encourage sustainable behaviour.

PubMed

Revell, Kirsten M A; Stanton, Neville A

2016-11-01

Householders' behaviour with their home heating systems is a considerable contributor to domestic energy consumption. To create a design specification for the 'scaffolding' needed for sustainable behaviour with home heating controls, Norman's (1986) Gulf of Execution and Evaluation was applied to the home heating system. A Home Heating Design Model (DM) was produced with a home heating expert. Norman's (1986) 7 Stages of Activity were considered to derive a Compatible User Mental Model (CUMM) of a typical Heating System. Considerable variation in the concepts needed at each stage was found. Elements that could be derived from the DM supported stages relating to action specification, execution, perception and interpretation, but many are not communicated in the design of typical heating controls. Stages relating to goals, intentions and evaluation required concepts beyond the DM. A systems view that tackles design for sustainable behaviour from a variety of levels is needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methodology for estimation of time-dependent surface heat flux due to cryogen spray cooling.

PubMed

Tunnell, James W; Torres, Jorge H; Anvari, Bahman

2002-01-01

Cryogen spray cooling (CSC) is an effective technique to protect the epidermis during cutaneous laser therapies. Spraying a cryogen onto the skin surface creates a time-varying heat flux, effectively cooling the skin during and following the cryogen spurt. In previous studies mathematical models were developed to predict the human skin temperature profiles during the cryogen spraying time. However, no studies have accounted for the additional cooling due to residual cryogen left on the skin surface following the spurt termination. We formulate and solve an inverse heat conduction (IHC) problem to predict the time-varying surface heat flux both during and following a cryogen spurt. The IHC formulation uses measured temperature profiles from within a medium to estimate the surface heat flux. We implement a one-dimensional sequential function specification method (SFSM) to estimate the surface heat flux from internal temperatures measured within an in vitro model in response to a cryogen spurt. Solution accuracy and experimental errors are examined using simulated temperature data. Heat flux following spurt termination appears substantial; however, it is less than that during the spraying time. The estimated time-varying heat flux can subsequently be used in forward heat conduction models to estimate temperature profiles in skin during and following a cryogen spurt and predict appropriate timing for onset of the laser pulse.

Channel size influence on the heat flux density at zero net mass flow in the non-linear transport regime between 1.2 and 2.1 K

NASA Technical Reports Server (NTRS)

Frederking, T. H. K.; Yuan, S. W. K.; Lee, J. M.; Sun, G. S.

1987-01-01

Porous media and narrow ducts of simple shape at zero net mass flow (ZNMF) are used to investigate the influence of pore size on the entropy/heat convection rate at ZNMF. The study is relevant to the development of specific types of phase separators. Previous work on heat transport by convection is extended to porous media without mass loss. The experimental results show the influence of pore size on heat flux for permeabilities between 10 to the -8th and 10 to the -6th sq cm. ZNMF plug data are found to be similar to results obtained for vapor liquid phase separation.

Development of linear projecting in studies of non-linear flow. Acoustic heating induced by non-periodic sound

NASA Astrophysics Data System (ADS)

Perelomova, Anna

2006-08-01

The equation of energy balance is subdivided into two dynamics equations, one describing evolution of the dominative sound, and the second one responsible for acoustic heating. The first one is the famous KZK equation, and the second one is a novel equation governing acoustic heating. The novel dynamic equation considers both periodic and non-periodic sound. Quasi-plane geometry of flow is supposed. Subdividing is provided on the base of specific links of every mode. Media with arbitrary thermic T(p,ρ) and caloric e(p,ρ) equations of state are considered. Individual roles of thermal conductivity and viscosity in the heating induced by aperiodic sound in the ideal gases and media different from ideal gases are discussed.

Experimental Study of Fuel Heating at Low Temperatures in a Wing Tank Model, Volume 1

NASA Technical Reports Server (NTRS)

Stockemer, F. J.

1981-01-01

Scale model fuel heating systems for use with aviation hydrocarbon fuel at low temperatures were investigated. The effectiveness of the heating systems in providing flowability and pumpability at extreme low temperature when some freezing of the fuel would otherwise occur is evaluated. The test tank simulated a section of an outer wing tank, and was chilled on the upper and lower surfaces. Turbine engine lubricating oil was heated, and recirculating fuel transferred the heat. Fuels included: a commercial Jet A; an intermediate freeze point distillate; a higher freeze point distillate blended according to Experimental Referee Broadened Specification guidelines; and a higher freeze point paraffinic distillate used in a preceding investigation. Each fuel was chilled to selected temperature to evaluate unpumpable solid formation (holdup). Tests simulating extreme cold weather flight, without heating, provided baseline fuel holdup data. Heating and recirculating fuel increased bulk temperature significantly; it had a relatively small effect on temperature near the bottom of the tank. Methods which increased penetration of heated fuel into the lower boundary layer improved the capability for reducing holdup.

Modeling of Austenite Grain Growth During Austenitization in a Low Alloy Steel

NASA Astrophysics Data System (ADS)

Dong, Dingqian; Chen, Fei; Cui, Zhenshan

2016-01-01

The main purpose of this work is to develop a pragmatic model to predict austenite grain growth in a nuclear reactor pressure vessel steel. Austenite grain growth kinetics has been investigated under different heating conditions, involving heating temperature, holding time, as well as heating rate. Based on the experimental results, the mathematical model was established by regression analysis. The model predictions present a good agreement with the experimental data. Meanwhile, grain boundary precipitates and pinning effects on grain growth were studied by transmission electron microscopy. It is found that with the increasing of the temperature, the second-phase particles tend to be dissolved and the pinning effects become smaller, which results in a rapid growth of certain large grains with favorable orientation. The results from this study provide the basis for the establishment of large-sized ingot heating specification for SA508-III steel.

Sequence and structure determinants of Drosophila Hsp70 mRNA translation: 5'UTR secondary structure specifically inhibits heat shock protein mRNA translation.

PubMed Central

Hess, M A; Duncan, R F

1996-01-01

Preferential translation of Drosophila heat shock protein 70 (Hsp70) mRNA requires only the 5'-untranslated region (5'-UTR). The sequence of this region suggests that it has relatively little secondary structure, which may facilitate efficient protein synthesis initiation. To determine whether minimal 5'-UTR secondary structure is required for preferential translation during heat shock, the effect of introducing stem-loops into the Hsp70 mRNA 5'-UTR was measured. Stem-loops of -11 kcal/mol abolished translation during heat shock, but did not reduce translation in non-heat shocked cells. A -22 kcal/mol stem-loop was required to comparably inhibit translation during growth at normal temperatures. To investigate whether specific sequence elements are also required for efficient preferential translation, deletion and mutation analyses were conducted in a truncated Hsp70 5'-UTR containing only the cap-proximal and AUG-proximal segments. Linker-scanner mutations in the cap-proximal segment (+1 to +37) did not impair translation. Re-ordering the segments reduced mRNA translational efficiency by 50%. Deleting the AUG-proximal segment severely inhibited translation. A 5-extension of the full-length leader specifically impaired heat shock translation. These results indicate that heat shock reduces the capacity to unwind 5-UTR secondary structure, allowing only mRNAs with minimal 5'-UTR secondary structure to be efficiently translated. A function for specific sequences is also suggested. PMID:8710519

Day and night heat stress trigger different transcriptomic responses in green and ripening grapevine (vitis vinifera) fruit

PubMed Central

2014-01-01

Background Global climate change will noticeably affect plant vegetative and reproductive development. The recent increase in temperatures has already impacted yields and composition of berries in many grapevine-growing regions. Physiological processes underlying temperature response and tolerance of the grapevine fruit have not been extensively investigated. To date, all studies investigating the molecular regulation of fleshly fruit response to abiotic stress were only conducted during the day, overlooking possible critical night-specific variations. The present study explores the night and day transcriptomic response of grapevine fruit to heat stress at several developmental stages. Short heat stresses (2 h) were applied at day and night to vines bearing clusters sequentially ordered according to the developmental stages along their vertical axes. The recently proposed microvine model (DRCF-Dwarf Rapid Cycling and Continuous Flowering) was grown in climatic chambers in order to circumvent common constraints and biases inevitable in field experiments with perennial macrovines. Post-véraison berry heterogeneity within clusters was avoided by constituting homogenous batches following organic acids and sugars measurements of individual berries. A whole genome transcriptomic approach was subsequently conducted using NimbleGen 090818 Vitis 12X (30 K) microarrays. Results Present work reveals significant differences in heat stress responsive pathways according to day or night treatment, in particular regarding genes associated with acidity and phenylpropanoid metabolism. Precise distinction of ripening stages led to stage-specific detection of malic acid and anthocyanin-related transcripts modulated by heat stress. Important changes in cell wall modification related processes as well as indications for heat-induced delay of ripening and sugar accumulation were observed at véraison, an effect that was reversed at later stages. Conclusions This first day - night study on heat stress adaption of the grapevine berry shows that the transcriptome of fleshy fruits is differentially affected by abiotic stress at night. The present results emphasize the necessity of including different developmental stages and especially several daytime points in transcriptomic studies. PMID:24774299

Heat and PAHs Emissions in Indoor Kitchen Air and Its Impact on Kidney Dysfunctions among Kitchen Workers in Lucknow, North India.

PubMed

Singh, Amarnath; Kamal, Ritul; Mudiam, Mohana Krishna Reddy; Gupta, Manoj Kumar; Satyanarayana, Gubbala Naga Venkata; Bihari, Vipin; Shukla, Nishi; Khan, Altaf Hussain; Kesavachandran, Chandrasekharan Nair

2016-01-01

Indoor air quality and heat exposure have become an important occupational health and safety concern in several workplaces including kitchens of hotels. This study investigated the heat, particulate matter (PM), total volatile organic compounds (TVOCs) and polycyclic aromatic hydrocarbons (PAHs) emissions in indoor air of commercial kitchen and its association with kidney dysfunctions among kitchen workers. A cross sectional study was conducted on 94 kitchen workers employed at commercial kitchen in Lucknow city, North India. A questionnaire-based survey was conducted to collect the personal and occupational history of the kitchen workers. The urine analysis for specific gravity and microalbuminuria was conducted among the study subjects. Indoor air temperature, humidity, wet/ dry bulb temperature and humidex heat stress was monitored during cooking activities at the kitchen. Particulate matter (PM) for 1 and 2.5 microns were monitored in kitchen during working hours using Hazdust. PAHS in indoor air was analysed using UHPLC. Urinary hydroxy-PAHs in kitchen workers were measured using GC/MS-MS. Higher indoor air temperature, relative humidity, PM1 and PM2.5 (p<0.001) was observed in the kitchen due to cooking process. Indoor air PAHs identified are Napthalene, fluorine, acenaphthene, phenanthrene, pyrene, chrysene and indeno [1,2,3-cd) pyrene. Concentrations of all PAHs identified in kitchen were above the permissible OSHA norms for indoor air. Specific gravity of urine was significantly higher among the kitchen workers (p<0.001) as compared to the control group. Also, the prevalence of microalbuminuria was higher (p<0.001) among kitchen workers. Urinary PAH metabolites detected among kitchen workers were 1-NAP, 9-HF, 3-HF, 9-PHN and 1-OHP. Continuous heat exposure in kitchens due to cooking can alter kidney functions viz., high specific gravity of urine in kitchen workers. Exposure to PM, VOCs and PAHs in indoor air and presence of urinary PAHs metabolites may lead to inflammation, which can cause microalbuminuria in kitchen workers, as observed in the present study.

Heat and PAHs Emissions in Indoor Kitchen Air and Its Impact on Kidney Dysfunctions among Kitchen Workers in Lucknow, North India

PubMed Central

Singh, Amarnath; Kamal, Ritul; Mudiam, Mohana Krishna Reddy; Gupta, Manoj Kumar; Satyanarayana, Gubbala Naga Venkata; Bihari, Vipin; Shukla, Nishi; Khan, Altaf Hussain; Kesavachandran, Chandrasekharan Nair

2016-01-01

Indoor air quality and heat exposure have become an important occupational health and safety concern in several workplaces including kitchens of hotels. This study investigated the heat, particulate matter (PM), total volatile organic compounds (TVOCs) and polycyclic aromatic hydrocarbons (PAHs) emissions in indoor air of commercial kitchen and its association with kidney dysfunctions among kitchen workers. A cross sectional study was conducted on 94 kitchen workers employed at commercial kitchen in Lucknow city, North India. A questionnaire-based survey was conducted to collect the personal and occupational history of the kitchen workers. The urine analysis for specific gravity and microalbuminuria was conducted among the study subjects. Indoor air temperature, humidity, wet/ dry bulb temperature and humidex heat stress was monitored during cooking activities at the kitchen. Particulate matter (PM) for 1 and 2.5 microns were monitored in kitchen during working hours using Hazdust. PAHS in indoor air was analysed using UHPLC. Urinary hydroxy-PAHs in kitchen workers were measured using GC/MS-MS. Higher indoor air temperature, relative humidity, PM1 and PM2.5 (p<0.001) was observed in the kitchen due to cooking process. Indoor air PAHs identified are Napthalene, fluorine, acenaphthene, phenanthrene, pyrene, chrysene and indeno [1,2,3-cd) pyrene. Concentrations of all PAHs identified in kitchen were above the permissible OSHA norms for indoor air. Specific gravity of urine was significantly higher among the kitchen workers (p<0.001) as compared to the control group. Also, the prevalence of microalbuminuria was higher (p<0.001) among kitchen workers. Urinary PAH metabolites detected among kitchen workers were 1-NAP, 9-HF, 3-HF, 9-PHN and 1-OHP. Continuous heat exposure in kitchens due to cooking can alter kidney functions viz., high specific gravity of urine in kitchen workers. Exposure to PM, VOCs and PAHs in indoor air and presence of urinary PAHs metabolites may lead to inflammation, which can cause microalbuminuria in kitchen workers, as observed in the present study. PMID:26871707

Transcriptome analysis in tardigrade species reveals specific molecular pathways for stress adaptations.

PubMed

Förster, Frank; Beisser, Daniela; Grohme, Markus A; Liang, Chunguang; Mali, Brahim; Siegl, Alexander Matthias; Engelmann, Julia C; Shkumatov, Alexander V; Schokraie, Elham; Müller, Tobias; Schnölzer, Martina; Schill, Ralph O; Frohme, Marcus; Dandekar, Thomas

2012-01-01

Tardigrades have unique stress-adaptations that allow them to survive extremes of cold, heat, radiation and vacuum. To study this, encoded protein clusters and pathways from an ongoing transcriptome study on the tardigrade Milnesium tardigradum were analyzed using bioinformatics tools and compared to expressed sequence tags (ESTs) from Hypsibius dujardini, revealing major pathways involved in resistance against extreme environmental conditions. ESTs are available on the Tardigrade Workbench along with software and databank updates. Our analysis reveals that RNA stability motifs for M. tardigradum are different from typical motifs known from higher animals. M. tardigradum and H. dujardini protein clusters and conserved domains imply metabolic storage pathways for glycogen, glycolipids and specific secondary metabolism as well as stress response pathways (including heat shock proteins, bmh2, and specific repair pathways). Redox-, DNA-, stress- and protein protection pathways complement specific repair capabilities to achieve the strong robustness of M. tardigradum. These pathways are partly conserved in other animals and their manipulation could boost stress adaptation even in human cells. However, the unique combination of resistance and repair pathways make tardigrades and M. tardigradum in particular so highly stress resistant.

Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

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

Bryantsev, A.L.; Chechenova, M.B.; Shelden, E.A.

During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absencemore » of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.« less

Characterization of heat-induced interaction of neutral liposome with lipid membrane of Streptomyces griseus cell.

PubMed

Ngo, Kien Xuan; Umakoshi, Hiroshi; Shimanouchi, Toshinori; Kuboi, Ryoichi

2009-10-15

The interaction between the neutral 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes and cell membrane of Streptomyces griseus induced by the heat treatment at specific temperature was investigated, focusing on the internalization of the neutral POPC liposomes with S. griseus cells. In an attempt to clarify the modes of liposome internalization, various kinds of inhibitors of endocytotic pathways were used to treat S. griseus cells. The efficiency of the heat treatment on liposome-cell membrane interactions was finally characterized based on the hydrophobic, electrostatic interactions and hydration effect. In fact, the internalization of the neutral liposomes into these cells was found to show higher rate and greater amount at higher temperatures. The kinetic study showed that the maximum amount of the internalized liposomes was, respectively, 469 x 10(5) and 643 x 10(5) liposomes/cell at 37 and 41 degrees C. The internalization of the neutral liposomes induced by the heat treatment was characterized, implying that the endocytosis occurred. The interactions involving the internalization, adsorption, and fusion of these liposomes with S. griseus cells were mainly contributed by the hydrophobic interaction and the unstable hydrogen bonds caused by the loss of water of surface hydration of cell membrane rather than the electrostatic interaction under the specific heat condition.

A phonon thermodynamics approach of gold nanofluids synthesized in solution plasma

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

Heo, YongKang, E-mail: yk@rd.numse.nagoya-u.ac.jp; Aburaya, Daiki, E-mail: daiki@rd.numse.nagoya-u.ac.jp; Antoaneta Bratescu, Maria, E-mail: maria@rd.numse.nagoya-u.ac.jp

2014-03-17

The phonon thermodynamics theory for liquids was applied to explain the thermal characteristics of gold nanofluids synthesized by a simple, one-step, and chemical-free method using an electrical discharge in a liquid environment termed solution plasma process. The specific heat capacity of nanofluids was measured with a differential scanning calorimeter using the ratio between the differential heat flow rate and the heating rate. The decrease of the specific heat capacity with 10% of gold nanofluids relative to water was explained by the decrease of Frenkel relaxation time with 22%, considering a solid-like state model of liquids.

How to Decide on Modeling Details: Risk and Benefit Assessment.

PubMed

Özilgen, Mustafa

Mathematical models based on thermodynamic, kinetic, heat, and mass transfer analysis are central to this chapter. Microbial growth, death, enzyme inactivation models, and the modeling of material properties, including those pertinent to conduction and convection heating, mass transfer, such as diffusion and convective mass transfer, and thermodynamic properties, such as specific heat, enthalpy, and Gibbs free energy of formation and specific chemical exergy are also needed in this task. The origins, simplifying assumptions, and uses of model equations are discussed in this chapter, together with their benefits. The simplified forms of these models are sometimes referred to as "laws," such as "the first law of thermodynamics" or "Fick's second law." Starting to modeling a study with such "laws" without considering the conditions under which they are valid runs the risk of ending up with erronous conclusions. On the other hand, models started with fundamental concepts and simplified with appropriate considerations may offer explanations for the phenomena which may not be obtained just with measurements or unprocessed experimental data. The discussion presented here is strengthened with case studies and references to the literature.

Boundaries of the critical state stability in a hard superconductor Nb3Al in the H-T plane

NASA Astrophysics Data System (ADS)

Chabanenko, V. V.; Vasiliev, S. V.; Nabiałek, A.; Shishmakov, A. S.; Pérez-Rodríguez, F.; Rusakov, V. F.; Szewczyk, A.; Kodess, B. N.; Gutowska, M.; Wieckowski, J.; Szymczak, H.

2013-04-01

The instability of the critical state in a type-II superconductor Nb3Al is studied for the first time for simultaneous consideration of real dependences of thermal and conductive properties of the material on temperature T and magnetic field He. To do this the dependences of specific heat C(T,Hе), magnetization M(T,He) and magnetostriction ΔL(T,He) of the superconductor were investigated experimentally in a strong magnetic field (up to 12 T). The gap width, the coefficient of the linear term, which determines the electronic contribution to the specific heat, the Debye temperature, and other parameters were found using experimental data on the heat capacity in a wide range of temperatures and magnetic fields Hc1 ≤ He ≤ Hc2. From experimental studies of magnetization the dependences of the critical current of the superconductor, Jc(T,He), were reconstructed. The hysteresis loops of magnetization and magnetostriction were calculated using experimental data for temperature and field dependences of the thermal and conductive properties.

Residential Variable-Capacity Heat Pumps Sized to Heating Loads

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

Munk, Jeffrey D.; Jackson, Roderick K.; Odukomaiya, Adewale

2014-01-01

Variable capacity heat pumps are an emerging technology offering significant energy savings potential and improved efficiency. With conventional single-speed systems, it is important to appropriately size heat pumps for the cooling load as over-sizing would result in cycling and insufficient latent capacity required for humidity control. These appropriately sized systems are often under-sized for the heating load and require inefficient supplemental electric resistance heat to meet the heating demand. Variable capacity heat pumps address these shortcomings by providing an opportunity to intentionally size systems for the dominant heating season load without adverse effects of cycling or insufficient dehumidification in themore » cooling season. This intentionally-sized system could result in significant energy savings in the heating season, as the need for inefficient supplemental electric resistance heat is drastically reduced. This is a continuation of a study evaluating the energy consumption of variable capacity heat pumps installed in two unoccupied research homes in Farragut, a suburb of Knoxville, Tennessee. In this particular study, space conditioning systems are intentionally sized for the heating season loads to provide an opportunity to understand and evaluate the impact this would have on electric resistance heat use and dehumidification. The results and conclusions drawn through this research are valid and specific for portions of the Southeastern and Midwestern United States falling in the mixed-humid climate zone. While other regions in the U.S. do not experience this type of climate, this work provides a basis for, and can help understand the implications of other climate zones on residential space conditioning energy consumption. The data presented here will provide a framework for fine tuning residential building EnergyPlus models that are being developed.« less

Genome-wide analysis of the heat stress response in Zebu (Sahiwal) cattle.

PubMed

Mehla, Kusum; Magotra, Ankit; Choudhary, Jyoti; Singh, A K; Mohanty, A K; Upadhyay, R C; Srinivasan, Surendran; Gupta, Pankaj; Choudhary, Neelam; Antony, Bristo; Khan, Farheen

2014-01-10

Environmental-induced hyperthermia compromises animal production with drastic economic consequences to global animal agriculture and jeopardizes animal welfare. Heat stress is a major stressor that occurs as a result of an imbalance between heat production within the body and its dissipation and it affects animals at cellular, molecular and ecological levels. The molecular mechanism underlying the physiology of heat stress in the cattle remains undefined. The present study sought to evaluate mRNA expression profiles in the cattle blood in response to heat stress. In this study we report the genes that were differentially expressed in response to heat stress using global scale genome expression technology (Microarray). Four Sahiwal heifers were exposed to 42°C with 90% humidity for 4h followed by normothermia. Gene expression changes include activation of heat shock transcription factor 1 (HSF1), increased expression of heat shock proteins (HSP) and decreased expression and synthesis of other proteins, immune system activation via extracellular secretion of HSP. A cDNA microarray analysis found 140 transcripts to be up-regulated and 77 down-regulated in the cattle blood after heat treatment (P<0.05). But still a comprehensive explanation for the direction of fold change and the specific genes involved in response to acute heat stress still remains to be explored. These findings may provide insights into the underlying mechanism of physiology of heat stress in cattle. Understanding the biology and mechanisms of heat stress is critical to developing approaches to ameliorate current production issues for improving animal performance and agriculture economics. © 2013 Elsevier B.V. All rights reserved.

Under-humidification and over-humidification during moderate induced hypothermia with usual devices.

PubMed

Lellouche, François; Qader, Siham; Taille, Solenne; Lyazidi, Aissam; Brochard, Laurent

2006-07-01

In mechanically ventilated patients with induced hypothermia, the efficacy of heat and moisture exchangers and heated humidifiers to adequately humidify the airway is poorly known. The aim of the study was to assess the efficacy of different humidification devices during moderate hypothermia. Prospective, cross-over randomized study. Medical Intensive Care Unit in a University Hospital. Nine adult patients hospitalized after cardiac arrest in whom moderate hypothermia was induced (33 degrees C for 24[Symbol: see text]h). Patients were ventilated at admission (period designated "normothermia") with a heat and moisture exchanger, and were randomly ventilated during hypothermia with a heat and moisture exchanger, a heated humidifier, and an active heat and moisture exchanger. Core temperature, inspired and expired gas absolute and relative humidity were measured. Each system demonstrated limitations in its ability to humidify gases in the specific situation of hypothermia. Performances of heat and moisture exchangers were closely correlated to core temperature (r (2)[Symbol: see text]=[Symbol: see text]0.84). During hypothermia, heat and moisture exchangers led to major under-humidification, with absolute humidity below 25[Symbol: see text]mgH(2)O/l. The active heat and moisture exchanger slightly improved humidification. Heated humidifiers were mostly adequate but led to over-humidification in some patients, with inspiratory absolute humidity higher than maximal water content at 33 degrees C with a positive balance between inspiratory and expiratory water content. These results suggest that in the case of moderate hypothermia, heat and moisture exchangers should be used cautiously and that heated humidifiers may lead to over-humidification with the currently recommended settings.

75 FR 34181 - Connecticut Yankee Atomic Power Company, Haddam Neck Plant, Independent Spent Fuel Storage...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

... Specification (TS) Surveillance Requirement 3.1.6.1 to verify the operability of the concrete cask heat removal... Specification (TS) Surveillance Requirement 3.1.6.1 to verify the operability of the concrete cask heat removal...

40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Specific provisions for monitoring NOX... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for...-diluent continuous emission monitoring system (consisting of a NOX pollutant concentration monitor, an O2...

40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Specific provisions for monitoring NOX... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for...-diluent continuous emission monitoring system (consisting of a NOX pollutant concentration monitor, an O2...

40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Specific provisions for monitoring NOX... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for...-diluent continuous emission monitoring system (consisting of a NOX pollutant concentration monitor, an O2...

Heat-Related Deaths in Hot Cities: Estimates of Human Tolerance to High Temperature Thresholds

PubMed Central

Harlan, Sharon L.; Chowell, Gerardo; Yang, Shuo; Petitti, Diana B.; Morales Butler, Emmanuel J.; Ruddell, Benjamin L.; Ruddell, Darren M.

2014-01-01

In this study we characterized the relationship between temperature and mortality in central Arizona desert cities that have an extremely hot climate. Relationships between daily maximum apparent temperature (ATmax) and mortality for eight condition-specific causes and all-cause deaths were modeled for all residents and separately for males and females ages <65 and ≥65 during the months May–October for years 2000–2008. The most robust relationship was between ATmax on day of death and mortality from direct exposure to high environmental heat. For this condition-specific cause of death, the heat thresholds in all gender and age groups (ATmax = 90–97 °F; 32.2‒36.1 °C) were below local median seasonal temperatures in the study period (ATmax = 99.5 °F; 37.5 °C). Heat threshold was defined as ATmax at which the mortality ratio begins an exponential upward trend. Thresholds were identified in younger and older females for cardiac disease/stroke mortality (ATmax = 106 and 108 °F; 41.1 and 42.2 °C) with a one-day lag. Thresholds were also identified for mortality from respiratory diseases in older people (ATmax = 109 °F; 42.8 °C) and for all-cause mortality in females (ATmax = 107 °F; 41.7 °C) and males <65 years (ATmax = 102 °F; 38.9 °C). Heat-related mortality in a region that has already made some adaptations to predictable periods of extremely high temperatures suggests that more extensive and targeted heat-adaptation plans for climate change are needed in cities worldwide. PMID:24658410

Environmental heat stress enhances mental fatigue during sustained attention task performing: evidence from an ASL perfusion study.

PubMed

Qian, Shaowen; Li, Min; Li, Guoying; Liu, Kai; Li, Bo; Jiang, Qingjun; Li, Li; Yang, Zhen; Sun, Gang

2015-03-01

This study was to investigate the potential enhancing effect of heat stress on mental fatigue progression during sustained attention task using arterial spin labeling (ASL) imaging. Twenty participants underwent two thermal exposures in an environmental chamber: normothermic (NT) condition (25°C, 1h) and hyperthermic (HT) condition (50°C, 1h). After thermal exposure, they performed a twenty-minute psychomotor vigilance test (PVT) in the scanner. Behavioral analysis revealed progressively increasing subjective fatigue ratings and reaction time as PVT progressed. Moreover, heat stress caused worse performance. Perfusion imaging analyses showed significant resting-state cerebral blood flow (CBF) alterations after heat exposure. Specifically, increased CBF mainly gathered in thalamic-brainstem area while decreased CBF predominantly located in fronto-parietal areas, anterior cingulate cortex, posterior cingulate cortex, and medial frontal cortex. More importantly, diverse CBF distributions and trend of changes between both conditions were observed as the fatigue level progressed during subsequent PVT task. Specifically, higher CBF and enhanced rising trend were presented in superior parietal lobe, precuneus, posterior cingulate cortex and anterior cingulate cortex, while lower CBF or inhibited rising trend was found in dorsolateral frontal cortex, medial frontal cortex, inferior parietal lobe and thalamic-brainstem areas. Furthermore, the decrease of post-heat resting-state CBF in fronto-parietal cortex was correlated with subsequent slower reaction time, suggesting prior disturbed resting-state CBF might be indicator of performance potential and fatigue level in following task. These findings may provide proof for such a view: heat stress has a potential fatigue-enhancing effect when individual is performing highly cognition-demanding attention task. Copyright © 2014 Elsevier B.V. All rights reserved.

Round robin test on the measurement of the specific heat of solar salt

NASA Astrophysics Data System (ADS)

Muñoz-Sánchez, Belén; Nieto-Maestre, Javier; González-Aguilar, José; Julia, José Enrique; Navarrete, Nuria; Faik, Abdessamad; Bauer, Thomas; Bonk, Alexander; Navarro, María Elena; Ding, Yulong; Uranga, Nerea; Veca, Elisabetta; Sau, Salvatore; Giménez, Pau; García, Pierre; Burgaleta, Juan Ignacio

2017-06-01

Solar salt (SS), a well-known non-eutectic mixture of sodium nitrate (60% w/w) and potassium nitrate (40% w/w), is commonly used either as Thermal Energy Storage (TES) material (double tank technology) or Heat Transfer Fluid (HTF) (solar tower) in modern CSP plants worldwide. The specific heat (cp, kJ kg-1 °C-1) of SS is a very important property in order to support the design of new CSP Plants or develop novel materials based on SS. A high scientific effort has been dedicated to perform a suitable thermophysical characterization of this material. However, there is still a great discrepancy among the cp values reported by different authors1. These differences may be due to either experimental errors (random or systematic) or divergences in the starting material (grade of purity, presence of impurities and/or water). In order to avoid the second source of uncertainty (the starting material), a Round Robin Test (RRT) was proposed starting from a common material. In this way, the different methods from each laboratory could be compared. The study should lay the foundations for the establishment of a systematic procedure for the measurement of the specific heat of this kind of materials. Nine institutions, research centers and companies, accepted the proposal and are contributing with their results. The initiative was organized within the Workshop SolarPACES Task III - Material activity.

Untargeted metabolomic analysis of tomato pollen development and heat stress response.

PubMed

Paupière, Marine J; Müller, Florian; Li, Hanjing; Rieu, Ivo; Tikunov, Yury M; Visser, Richard G F; Bovy, Arnaud G

2017-06-01

Pollen development metabolomics. Developing pollen is among the plant structures most sensitive to high temperatures, and a decrease in pollen viability is often associated with an alteration of metabolite content. Most of the metabolic studies of pollen have focused on a specific group of compounds, which limits the identification of physiologically important metabolites. To get a better insight into pollen development and the pollen heat stress response, we used a liquid chromatography-mass spectrometry platform to detect secondary metabolites in pollen of tomato (Solanum lycopersicum L.) at three developmental stages under control conditions and after a short heat stress at 38 °C. Under control conditions, the young microspores accumulated a large amount of alkaloids and polyamines, whereas the mature pollen strongly accumulated flavonoids. The heat stress treatment led to accumulation of flavonoids in the microspore. The biological role of the detected metabolites is discussed. This study provides the first untargeted metabolomic analysis of developing pollen under a changing environment that can serve as reference for further studies.

Effects of heat shocks on microbial community structure and microbial activity of a methanogenic enrichment degrading benzoate.

PubMed

Mei, R; Narihiro, T; Nobu, M K; Liu, W-T

2016-11-01

In anaerobic digesters, temperature fluctuation could lead to process instability and failure. It is still not well understood how digester microbiota as a whole respond to heat shock, and what specific organisms are vulnerable to perturbation or responsible for process recovery after perturbation. To address these questions, a mesophilic benzoate-degrading methanogenic culture enriched from digester was subjected to different levels of heat shock. Three types of methane production profiles after perturbation were observed in comparison to the control: uninhibited, inhibited with later recovery, and inhibited without recovery. These responses were correlated with the microbial community compositions based on the analyses of 16S rRNA and 16S rRNA gene. Specifically, the primary benzoate-degrading syntroph was highly affected by heat shock, and its abundance and activity were both crucial to the restoration of benzoate degradation after heat shock. In contrast, methanogens were stable regardless whether methane production was inhibited. Populations related to 'Candidatus Cloacimonetes' and Firmicutes showed stimulated growth. These observations indicated distinct physiological traits and ecological niches associated with individual microbial groups. The results obtained after exposure to heat shock can be critical to more comprehensive characterization of digester ecology under perturbations. Anaerobic digestion is an essential step in municipal wastewater treatment owing to its striking capacity of reducing wasted sludge and recovering energy. However, as an elaborate microbial process, it requires constant temperature control and is sensitive to heat shock. In this study, we explored the microbial response to heat shock of a methanogenic culture enriched from anaerobic digester sludge. Microorganisms that were vulnerable to perturbation or responsible for process recovery after perturbation were identified. © 2016 The Society for Applied Microbiology.

Cleavage and crosslinking of polymeric coal structures during pyrolysis. Final report

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

McMillen, D.F.; Malhotra, R.

1992-02-01

The ultimate objective of this project was to develop a better understanding of volatiles production to help optimize the yield and character of condensable coproducts during coal pyrolysis or mild gasification. The specific objectives were to (1) Develop pyrolysis procedures that minimize secondary reactions; and (2) Develop coal pretreatments that current knowledge suggests will prorate bond scission or prevent retrograde reactions. Our approach was to study the pyrolysis of coals and tar-loaded coals by using several techniques that span a range of heating rates and pressures. Slow-heating pyrolyses were performed at low pressures in the inlet of a field ionizationmore » mass spectrometer and at atmospheric pressures in a thermogravimetric analyzer. Moderately rapid-heating pyrolyses were performed in a vacuum TGA apparatus and in sealed silica ampules heated in a molten-salt bath. The fastest heating rates were achieved with laser pyrolysis at about 30,000 X/s. The high tar yield seen in this work where the entire volume of the coal particle becomes hot and fluid at very nearly the same time, taken together with the evident non-vapor transport of the tar under these conditions, emphasizes the importance of better understanding the development of fluidity during coal heating. This specifically includes the profound effects--long-recognized but poorly understood that mild oxidation has in suppressing coal fluidity. It also includes the more recently recognized fact that heating in the presence of an inert gas produced substantially greater fluidity than does heating in the presence of combustion gases, even if the conditions are very fuel rich and all the oxygen itself has already been consumed when the coal particles are encountered.« less

Cleavage and crosslinking of polymeric coal structures during pyrolysis

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

McMillen, D.F.; Malhotra, R.

1992-02-01

The ultimate objective of this project was to develop a better understanding of volatiles production to help optimize the yield and character of condensable coproducts during coal pyrolysis or mild gasification. The specific objectives were to (1) Develop pyrolysis procedures that minimize secondary reactions; and (2) Develop coal pretreatments that current knowledge suggests will prorate bond scission or prevent retrograde reactions. Our approach was to study the pyrolysis of coals and tar-loaded coals by using several techniques that span a range of heating rates and pressures. Slow-heating pyrolyses were performed at low pressures in the inlet of a field ionizationmore » mass spectrometer and at atmospheric pressures in a thermogravimetric analyzer. Moderately rapid-heating pyrolyses were performed in a vacuum TGA apparatus and in sealed silica ampules heated in a molten-salt bath. The fastest heating rates were achieved with laser pyrolysis at about 30,000 X/s. The high tar yield seen in this work where the entire volume of the coal particle becomes hot and fluid at very nearly the same time, taken together with the evident non-vapor transport of the tar under these conditions, emphasizes the importance of better understanding the development of fluidity during coal heating. This specifically includes the profound effects--long-recognized but poorly understood that mild oxidation has in suppressing coal fluidity. It also includes the more recently recognized fact that heating in the presence of an inert gas produced substantially greater fluidity than does heating in the presence of combustion gases, even if the conditions are very fuel rich and all the oxygen itself has already been consumed when the coal particles are encountered.« less

Effects of heat treatment on the mechanical properties of kenaf fiber

NASA Astrophysics Data System (ADS)

Carada, Paulo Teodoro D. L.; Fujii, Toru; Okubo, Kazuya

2016-05-01

Natural fibers are utilized in various ways. One specific application of it, is in the field natural fiber composite (NFC). Considerable amount of researches are conducted in this field due to rising concerns in the harmful effects of synthetic materials to the environment. Additionally, these researches are done in order to overcome the drawbacks which limit the wide use of natural fiber. A way to improve NFC is to look into the reinforcing component (natural fiber). Treatments, which are classified as mechanical or chemical in nature, can be done in order to improve the performance of the natural fiber. The aim of this study is to assess the effects of heat treatment in the mechanical properties of kenaf fiber. In addition, the response of mechanical properties after exposure to high moisture environment of heat-treated kenaf fibers was observed. Heat treatment was done for one hour with the following heating temperatures: 140, 160, 180, and 200 °C. X-ray diffraction analysis was done to calculate the crystallinity index of kenaf fibers after heat treatment. The results showed that increase in tensile strength can be attained when kenaf fibers are heat treated at 140 °C. However, the tensile modulus showed inconsistency with respect to heat treatment temperature. The computed crystallinity index of the fiber matched the tensile strength observed in non-treated and heat-treated kenaf fibers. The results obtained in this study can be used for applications where heat treatment on kenaf fibers is needed.

Effects of heat treatment on the mechanical properties of kenaf fiber

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

Carada, Paulo Teodoro D. L.; Fujii, Toru; Okubo, Kazuya

Natural fibers are utilized in various ways. One specific application of it, is in the field natural fiber composite (NFC). Considerable amount of researches are conducted in this field due to rising concerns in the harmful effects of synthetic materials to the environment. Additionally, these researches are done in order to overcome the drawbacks which limit the wide use of natural fiber. A way to improve NFC is to look into the reinforcing component (natural fiber). Treatments, which are classified as mechanical or chemical in nature, can be done in order to improve the performance of the natural fiber. Themore » aim of this study is to assess the effects of heat treatment in the mechanical properties of kenaf fiber. In addition, the response of mechanical properties after exposure to high moisture environment of heat-treated kenaf fibers was observed. Heat treatment was done for one hour with the following heating temperatures: 140, 160, 180, and 200 °C. X-ray diffraction analysis was done to calculate the crystallinity index of kenaf fibers after heat treatment. The results showed that increase in tensile strength can be attained when kenaf fibers are heat treated at 140 °C. However, the tensile modulus showed inconsistency with respect to heat treatment temperature. The computed crystallinity index of the fiber matched the tensile strength observed in non-treated and heat-treated kenaf fibers. The results obtained in this study can be used for applications where heat treatment on kenaf fibers is needed.« less

High ambient temperature and mortality: a review of epidemiologic studies from 2001 to 2008

PubMed Central

2009-01-01

Background This review examines recent evidence on mortality from elevated ambient temperature for studies published from January 2001 to December 2008. Methods PubMed was used to search for the following keywords: temperature, apparent temperature, heat, heat index, and mortality. The search was limited to the English language and epidemiologic studies. Studies that reported mortality counts or excess deaths following heat waves were excluded so that the focus remained on general ambient temperature and mortality in a variety of locations. Studies focusing on cold temperature effects were also excluded. Results Thirty-six total studies were presented in three tables: 1) elevated ambient temperature and mortality; 2) air pollutants as confounders and/or effect modifiers of the elevated ambient temperature and mortality association; and 3) vulnerable subgroups of the elevated ambient temperature-mortality association. The evidence suggests that particulate matter with less than 10 um in aerodynamic diameter and ozone may confound the association, while ozone was an effect modifier in the warmer months in some locations. Nonetheless, the independent effect of temperature and mortality was withheld. Elevated temperature was associated with increased risk for those dying from cardiovascular, respiratory, cerebrovascular, and some specific cardiovascular diseases, such as ischemic heart disease, congestive heart failure, and myocardial infarction. Vulnerable subgroups also included: Black racial/ethnic group, women, those with lower socioeconomic status, and several age groups, particularly the elderly over 65 years of age as well as infants and young children. Conclusion Many of these outcomes and vulnerable subgroups have only been identified in recent studies and varied by location and study population. Thus, region-specific policies, especially in urban areas, are vital to the mitigation of heat-related deaths. PMID:19758453

Preliminary design package for maxi-therm heat exchanger module

NASA Technical Reports Server (NTRS)

1978-01-01

Heat exchangers were developed for use in a solar heating and cooling system installed in a single family dwelling. Each of the three exchangers consisted of a heating and cooling module and a submersed electric water heating element. Information necessary to evaluate the preliminary design of the heat exchanger is presented in terms of the development and verification plans, performance specifications, installation and maintenance, and hazard analysis.

Smart Houses

NASA Technical Reports Server (NTRS)

1987-01-01

GWS takes plans for a new home and subjects them to intensive computerized analysis that does 10,000 calculations relative to expected heat loss and heat gain, then provides specifications designed specifically for each structure as to heating, cooling, ventilation and insulation. As construction progresses, GWS inspects the work of the electrical, plumbing and insulation contractors and installs its own Smart House Radiant Barrier. On completion of the home, GWS technicians use a machine that creates a vacuum in the house and enables computer calculation of the air exchanged, a measure of energy efficiency. Key factor is the radiant barrier, borrowed from the Apollo program. This is an adaptation of a highly effective aluminized heat shield as a radiation barrier holding in or keeping out heat, cold air and water vapor.

The influence of using heat storage with PCM on inlet and outlet temperatures in substation in DHS

NASA Astrophysics Data System (ADS)

Nogaj, Kinga; Turski, Michał; Sekret, Robert

2017-11-01

The main objective of this article is to indicate the direction of development of new generation heating systems that use phase change materials, and the important criteria needed when choosing a phase change material. The work contains a detailed classification of materials using the latent heat of organic and inorganic PCM. This references the technical possibilities of existing heat storage technologies. A specific objective was adopted to determine the effect of using heat storage with PCM on inlet and outlet temperatures in substation in district heating systems. The scope of the study included determining the parameters of the heat distribution network as a function of an outdoor air temperature within the range of -20°C to + 12°C. The object of analysis was chosen to be the heating system parameters: supply 120°C and return 60°C. It is located on the surface of 160km2, and supplies heat to 240,000 residents. The total length of the district heating network is 170 km. Based on the study, it was found that the most advantageous material that accumulates heat depends on the return temperature in the heating network. For the above analyzed case, the return temperature was in the range of 46°C to 57°C. The analysis showed that the most preferred materials using heat of phase change, have possible applications in heating networks and received a return temperature including salt hydrates, such as MgSO4·7H2O and Na2S2O3·5H2. The introduction of stored heat for the district heating system with the phase change material in the form of salt hydrates, allows the return temperature in the district heating to remain at temperatures compatible with the adopted regulatory table for temperatures outside the standard heating season.

System-wide identification of wild-type SUMO-2 conjugation sites

PubMed Central

Hendriks, Ivo A.; D'Souza, Rochelle C.; Chang, Jer-Gung; Mann, Matthias; Vertegaal, Alfred C. O.

2015-01-01

SUMOylation is a reversible post-translational modification (PTM) regulating all nuclear processes. Identification of SUMOylation sites by mass spectrometry (MS) has been hampered by bulky tryptic fragments, which thus far necessitated the use of mutated SUMO. Here we present a SUMO-specific protease-based methodology which circumvents this problem, dubbed Protease-Reliant Identification of SUMO Modification (PRISM). PRISM allows for detection of SUMOylated proteins as well as identification of specific sites of SUMOylation while using wild-type SUMO. The method is generic and could be widely applied to study lysine PTMs. We employ PRISM in combination with high-resolution MS to identify SUMOylation sites from HeLa cells under standard growth conditions and in response to heat shock. We identified 751 wild-type SUMOylation sites on endogenous proteins, including 200 dynamic SUMO sites in response to heat shock. Thus, we have developed a method capable of quantitatively studying wild-type mammalian SUMO at the site-specific and system-wide level. PMID:26073453

Desalination using low grade heat sources

NASA Astrophysics Data System (ADS)

Gude, Veera Gnaneswar

A new, low temperature, energy-efficient and sustainable desalination system has been developed in this research. This system operates under near-vacuum conditions created by exploiting natural means of gravity and barometric pressure head. The system can be driven by low grade heat sources such as solar energy or waste heat streams. Both theoretical and experimental studies were conducted under this research to evaluate and demonstrate the feasibility of the proposed process. Theoretical studies included thermodynamic analysis and process modeling to evaluate the performance of the process using the following alternate energy sources for driving the process: solar thermal energy, solar photovoltaic/thermal energy, geothermal energy, and process waste heat emissions. Experimental studies included prototype scale demonstration of the process using grid power as well as solar photovoltaic/thermal sources. Finally, the feasibility of the process in reclaiming potable-quality water from the effluent of the city wastewater treatment plant was studied. The following results have been obtained from theoretical analysis and modeling: (1) The proposed process can produce up to 8 L/d of freshwater for 1 m2 area of solar collector and evaporation chamber respectively with a specific energy requirement of 3122 kJ for 1 kg of freshwater production. (2) Photovoltaic/thermal (PV/T) energy can produce up to 200 L/d of freshwater with a 25 m2 PV/T module which meets the electricity needs of 21 kWh/d of a typical household as well. This configuration requires a specific energy of 3122 kJ for 1 kg of freshwater production. (3) 100 kg/hr of geothermal water at 60°C as heat source can produce up to 60 L/d of freshwater with a specific energy requirement of 3078 kJ for 1 kg of freshwater production. (4) Waste heat released from an air conditioning system rated at 3.25 kW cooling, can produce up to 125 L/d of freshwater. This configuration requires an additional energy of 208 kJ/kg of freshwater along with the waste heat released from the condenser of air-conditioning system. This additional energy requirement is about 60% of the energy required by a multi stage flash distillation process. The experimental studies were conducted in three phases. In the first phase, electric power from grid as energy source was used to demonstrate the feasibility of the proposed process. These tests showed that freshwater production rate of 0.25 kg/hr can be sustained at evaporation temperatures as low as 40°C with specific energy input of 3,370 kJ/kg, at efficiencies ranging from 65 to 70% during the winter. In the second phase, experiments were conducted utilizing direct solar thermal energy and photovoltaic energy as well. Four different combinations of energy sources were studied. The following results were obtained from these experimental studies: (1) Utilizing direct solar energy produced 4.9 L/d of freshwater with an evaporator area of 1 m2 with an average efficiency of 61%. This yield is two times that can be obtained from a flat solar still. The specific energy requirement for this configuration is 4157 kJ for production of 1 kilogram freshwater; (2) Utilizing direct solar energy with aid of a reflector produced 7.5 L/d of freshwater with an average efficiency more than 80%. The specific energy requirement for this configuration is 3118 kJ for production of 1 kilogram freshwater; (3) Utilizing direct solar energy during sunlight hours and photovoltaic energy during non-sunlight hours produced 12 L/d of freshwater with 1 m2 evaporator area and 6 m2 photovoltaic areas respectively. The specific energy requirement for this configuration is 2926 kJ for production of 1 kilogram freshwater. Finally, the feasibility of this process in reclaiming potable-quality water from the effluent of a domestic wastewater treatment plant was studied. The process was able to achieve the following reductions: total dissolved solids from 727 mg/L to 21 mg/L (97%); nitrates from 2.4 mg/L to <0.1 mg/L (> 95%); ammonia from 23.2 mg/L to < 0.5 mg/L (> 97%); and coliform from 77 to <0 mg/L (100%).

Competing pseudogap and impurity effects on the normal-state specific heat properties of cuprate superconductors

NASA Astrophysics Data System (ADS)

Dzhumanov, S.; Karimboev, E. X.

2014-07-01

In this paper, we show that the pseudogap in the excitation spectra of high-Tc cuprates together with the impurity phase and charge inhomogeneity plays key roles in determining the essential features of their anomalous specific heat properties observed above Tc. We consider the doped cuprate superconductor as a multi-carrier model system (which consists of intrinsic and extrinsic polarons and pre-formed bosonic Cooper pairs) and study the competing pseudogap and impurity effects on the normal-state electronic specific heat of high-Tc cuprates taking into account charge inhomogeneities. We argue that unconventional electron-phonon interactions are responsible for the precursor Cooper pairing in the polaronic band below a mean-field temperature T∗ and the existence of a pseudogap above Tc in the cuprates. The electronic specific heat Ce(T) of doped cuprates below T∗ is calculated taking into account three contributions coming from the excited components of Cooper pairs, the ideal Bose-gas of incoherent Cooper pairs and the unpaired carriers in the impurity band. Above T∗, two contributions to Ce(T) coming from the unpaired intrinsic and extrinsic polarons are calculated within the two-component degenerate Fermi-gas model. By comparing our results with the experimental Ce(T) data obtained for La- and Y-based cuprates, we find that the observed behaviors of Ce(T) (below and above T∗) are similar to the calculated results for Ce(T) and the BCS-type jumps of Ce(T) at T∗ may be depressed by the impurity effects and may become more or less pronounced BCS-type anomalies in Ce(T) .

An analysis of heat effects in different subpopulations of Bangladesh

NASA Astrophysics Data System (ADS)

Burkart, Katrin; Breitner, Susanne; Schneider, Alexandra; Khan, Md. Mobarak Hossain; Krämer, Alexander; Endlicher, Wilfried

2014-03-01

A substantial number of epidemiological studies have demonstrated an association between atmospheric conditions and human all-cause as well as cause-specific mortality. However, most research has been performed in industrialised countries, whereas little is known about the atmosphere-mortality relationship in developing countries. Especially with regard to modifications from non-atmospheric conditions and intra-population differences, there is a substantial research deficit. Within the scope of this study, we aimed to investigate the effects of heat in a multi-stratified manner, distinguishing by the cause of death, age, gender, location and socio-economic status. We examined 22,840 death counts using semi-parametric Poisson regression models, adjusting for a multitude of potential confounders. Although Bangladesh is dominated by an increase of mortality with decreasing (equivalent) temperatures over a wide range of values, the findings demonstrated the existence of partly strong heat effects at the upper end of the temperature distribution. Moreover, the study demonstrated that the strength of these heat effects varied considerably over the investigated subgroups. The adverse effects of heat were particularly pronounced for males and the elderly above 65 years. Moreover, we found increased adverse effects of heat for urban areas and for areas with a high socio-economic status. The increase in, and acceleration of, urbanisation in Bangladesh, as well as the rapid aging of the population and the increase in non-communicable diseases, suggest that the relevance of heat-related mortality might increase further. Considering rising global temperatures, the adverse effects of heat might be further aggravated.

Thermal transport properties of polycrystalline Pb2FeMoO6

NASA Astrophysics Data System (ADS)

Yuan, Xueping; Xu, Mingxiang

2018-06-01

Thermoelectric properties and specific heat of polycrystalline Pb2FeMoO6 have been systematically studied. The thermal conductivity increases monotonically with increasing of temperature, and reaches the maximum value 1.50 W m‑1 K‑1 at 350 K. The relatively low thermal conductivity is mainly attributed to the strong scattering effect of phonons at Fe/Mo sites. The negative Seebeck coefficient indicates the n-type conduction of the sample. The absolute value of S increases up to 20 μV K‑1 at 350 K. Due to the inhomogeneity resulting from Fe/Mo ions disorder, no distinct λ-type specific heat peak or anomaly typical for second-order transitions are observed.

Thermodynamic modeling of the solar wind plasma in the presence of envelope-modulated low-frequency Alfvén waves

NASA Astrophysics Data System (ADS)

Nariyuki, Y.

2018-06-01

Alfvénic fluctuation is a typical state of the solar wind turbulence. Due to its finite amplitude and envelope modulation, the Alfvénic fluctuation becomes compressible. In the present study, an analytical model of the specific heat ratio in the presence of envelope-modulated Alfvén waves is derived. Ion kinetic effects are modeled by using a semi-ideal (perfect) gas model, in which the specific heat ratio depends on temperature. It is shown that the fourth order polynomial approximation is in good agreement with the kinetic theory. The resultant model is also applied to the fast solar wind plasma.

Thermal expansion and specific heat of Cr2TeO6 and Fe2TeO6 by first principles calculations

NASA Astrophysics Data System (ADS)

Mishra, Vinayak

2018-05-01

Cr2TeO6 and Fe2TeO6 crystallize in tetragonal structure. These compounds are formed in nuclear reactors. Therefore, study of thermal expansion of these compounds is important. In this paper, using WIEN2k code we have calculated the volume dependent total energies E(V) of these materials at zero kelvin. Subsequently, we have applied the quasi harmonic approximation, in order to include the thermal effects. Using our calculations, we have predicted the thermal expansion and specific heat at high temperatures. The calculated properties for Fe2TeO6 are in very good agreement with the reported experimental results.

Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

NASA Astrophysics Data System (ADS)

Wang, Haipeng; Luo, Bingchi; Chang, Jian; Wei, Bingbo

2007-08-01

The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calorimeter over a wide temperature range from 1482 to 1818 K. A maximum undercooling of 221 K (0.13 T m) was achieved and the specific heat was determined as 44.71 J·mol-1·K-1. The excess specific heat, enthalpy change, entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results. It was found that the calculated results by traditional estimating methods can only describe the solidification process under low undercooling conditions. Only the experimental results can reflect the reality under high undercooling conditions. Meanwhile, the thermal diffusivity, thermal conductivity, and sound speed were derived from the present experimental results. Furthermore, the solidified microstructural morphology was examined, which consists of (Fe) and (Cu) phases. The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

Radiation-thermometric study of isolated hot molten metal spheres by containerless and contactless measurement techniques

NASA Astrophysics Data System (ADS)

Lee, G. W.; Jeon, S.; Park, C.; Kang, D. H.; Choi, B. I.; Park, S. N.

2013-09-01

An electrostatic levitation (ESL) device is developed to study the radiation-properties of liquid metals at high temperature. The technique provides good advantage, such as fast response of temperature change on a sample, clear features of recalescence and plateau during freezing, no contamination or no reaction with environment, easy control of supercooling deducing hypercooling limit, and relatively simple analysis of thermodynamic quantities because of only radiative cooling process under vacuum. In this study, we could obtain a hypercooling limit (i.e., maximum supercooling) of liquid Ti, 341 K using the ESL. An accurate ratio of the specific heat to total hemispherical emissivity of liquid Ti was obtained by Stefan-Boltzmann law. Then, the specific heat and total hemispherical emissivity of Ti liquid metal can be estimated with the hypercooling limit and known fusion enthalpy values of Ti, which has been rarely reported.

Stirling Engine External Heat System Design with Heat Pipe Heater.

DTIC Science & Technology

1986-07-01

Figure 10. However, the evaporator analysis is greatly simplified by making the conservative assumption of constant heat flux. This assumption results in...number Cold Start Data * " ROM density of the metal, gr/cm 3 CAPM specific heat of the metal, cal./gr. K ETHG effective gauze thickness: the

40 CFR 86.1306-96 - Equipment required and specifications; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., continuous hydrocarbon detector and a heated, continuous nitrogen oxide detector (see § 86.1310); methanol-fueled engines require a heated hydrocarbon detector, a methanol detector and a formaldehyde detector; either a heated or non-heated continuous hydrocarbon detector may be used with natural gas-fueled and...

40 CFR 86.1306-96 - Equipment required and specifications; overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., continuous hydrocarbon detector and a heated, continuous nitrogen oxide detector (see § 86.1310); methanol-fueled engines require a heated hydrocarbon detector, a methanol detector and a formaldehyde detector; either a heated or non-heated continuous hydrocarbon detector may be used with natural gas-fueled and...

40 CFR 86.1306-96 - Equipment required and specifications; overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., continuous hydrocarbon detector and a heated, continuous nitrogen oxide detector (see § 86.1310); methanol-fueled engines require a heated hydrocarbon detector, a methanol detector and a formaldehyde detector; either a heated or non-heated continuous hydrocarbon detector may be used with natural gas-fueled and...

40 CFR 86.1306-96 - Equipment required and specifications; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., continuous hydrocarbon detector and a heated, continuous nitrogen oxide detector (see § 86.1310); methanol-fueled engines require a heated hydrocarbon detector, a methanol detector and a formaldehyde detector; either a heated or non-heated continuous hydrocarbon detector may be used with natural gas-fueled and...

Walking dead: Permeabilization of heat-treated Geobacillus stearothermophilus ATCC 12980 spores under growth-preventing conditions.

PubMed

Mtimet, Narjes; Trunet, Clément; Mathot, Anne-Gabrielle; Venaille, Laurent; Leguérinel, Ivan; Coroller, Louis; Couvert, Olivier

2017-06-01

Although heat treatment is probably the oldest and the most common method used to inactivate spores in food processes, the specific mechanism of heat killing of spores is still not fully understood. The purpose of this study is to investigate the evolution of the permeabilization and the viability of heat-treated spores during storage under growth-preventing conditions. Geobacillus stearothermophilus spores were heat-treated under various conditions of temperature and pH, and then stored under conditions of temperature and pH that prevent growth. Spore survival was evaluated by count plating immediately after heat treatment, and then during storage over a period of months. Flow cytometry analyses were performed to investigate the Syto 9 permeability of heat-treated spores. Sub-lethally heat-treated spores of G. stearothermophilus were physically committed to permeabilization after heat treatment. However, prolonged heat treatment may abolish the spore permeabilization and block heat-treated spores in the refractive state. However, viability loss and permeabilization during heat treatment seem to be two different mechanisms that occur independently, and the loss of permeabilization properties takes place at a much slower rate than spore killing. Under growth-preventing conditions, viable heat-treated spores presumably lose their viability due to the permeabilization phenomena, which makes them more susceptible to the action of adverse conditions precluding growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determining the Equation of State (EoS) Parameters for Ballistic Gelatin

DTIC Science & Technology

2015-09-01

standard deviation. The specific heat measured at room temperature reported in (Winter 1975) is approximately 1.13 cal/g/°C (= 4.73 J /g/K). Fig. 4...Piatt 2010) Table 3 Specific heat capacity, average heat capacity, and standard deviation Temperature (°C) Cp [ J /(g·K)] Cp Cp Cp Average Cp...density amorphous ice and their implications on pressure induced amorphization. J Chem Physics. 2005;122:124710. Appleby-Thomas GJ, Hazell PJ

Solution of Radiation and Convection Heat-Transfer Problems

NASA Technical Reports Server (NTRS)

Oneill, R. F.

1986-01-01

Computer program P5399B developed to accommodate variety of fin-type heat conduction applications involving radiative or convective boundary conditions with additionally imposed local heat flux. Program also accommodates significant variety of one-dimensional heat-transfer problems not corresponding specifically to fin-type applications. Program easily accommodates all but few specialized one-dimensional heat-transfer analyses as well as many twodimensional analyses.

Evaluating the influence of plant-specific physiological parameterizations on the partitioning of land surface energy fluxes

NASA Astrophysics Data System (ADS)

Sulis, Mauro; Langensiepen, Matthias; Shrestha, Prabhakar; Schickling, Anke; Simmer, Clemens; Kollet, Stefan

2015-04-01

Vegetation has a significant influence on the partitioning of radiative forcing, the spatial and temporal variability of soil water and soil temperature. Therefore plant physiological properties play a key role in mediating and amplifying interactions and feedback mechanisms in the soil-vegetation-atmosphere continuum. Because of the direct impact on latent heat fluxes, these properties may also influence weather generating processes, such as the evolution of the atmospheric boundary layer (ABL). In land surface models, plant physiological properties are usually obtained from literature synthesis by unifying several plant/crop species in predefined vegetation classes. In this work, crop-specific physiological characteristics, retrieved from detailed field measurements, are included in the bio-physical parameterization of the Community Land Model (CLM), which is a component of the Terrestrial Systems Modeling Platform (TerrSysMP). The measured set of parameters for two typical European mid-latitudinal crops (sugar beet and winter wheat) is validated using eddy covariance measurements (sensible heat and latent heat) over multiple years from three measurement sites located in the North Rhine-Westphalia region, Germany. We found clear improvements of CLM simulations, when using the crop-specific physiological characteristics of the plants instead of the generic crop type when compared to the measurements. In particular, the increase of latent heat fluxes in conjunction with decreased sensible heat fluxes as simulated by the two new crop-specific parameter sets leads to an improved quantification of the diurnal energy partitioning. These findings are cross-validated using estimates of gross primary production extracted from net ecosystem exchange measurements. This independent analysis reveals that the better agreement between observed and simulated latent heat using the plant-specific physiological properties largely stems from an improved simulation of the photosynthesis process owing to a better estimation of the Rubisco enzyme kinematics. Finally, to evaluate the effects of the crop-specific parameterizations on the ABL dynamics, we perform a series of semi-idealized land-atmosphere coupled simulations by hypothesizing three cropland configurations. These numerical experiments reveal different heat and moisture budgets of the ABL that clearly impact the evolution of the boundary layer when using the crop-specific physiological properties.

Effect of Heat Stress on Concentrations of Faecal Cortisol Metabolites in Dairy Cows.

PubMed

Rees, A; Fischer-Tenhagen, C; Heuwieser, W

2016-06-01

The negative impact of heat stress on health and productivity of dairy cows is well known. Heat stress can be quantified with the temperature-humidity index (THI) and is defined as a THI ≥ 72. Additionally, animal welfare is affected in cows living under heat stress conditions. Finding a way to quantify heat stress in dairy cows has been of increasing interest over the past decades. Therefore, the objective of this study was to evaluate concentrations of faecal glucocorticoid metabolites [i.e. 11,17-dioxoandrostanes (11,17-DOA)] as an indirect stress parameter in dairy cows without heat stress (DOA 0), with heat stress on a single day (acute heat stress, DOA 1) or with more than a single day of heat stress (chronic heat stress, DOA 2). Cows were housed in five farms under moderate European climates. Two statistical approaches (approach 1 and approach 2) were assessed. Using approach 1, concentrations of faecal 11,17-DOA were compared among DOA 0, DOA 1 and DOA 2 samples regardless of their origin (i.e. cow, unpaired comparison with a one-way anova). Using approach 2, a cow was considered as its own control; that is 11,17-DOA was treated as a cow-specific factor and only paired samples were included in the analysis for this approach (paired comparison with t-tests). In approach 1 (p = 0.006) and approach 2 (p = 0.038), 11,17-DOA values of cows under acute heat stress were higher compared to those of cows without heat stress. Our results also indicate that acute heat stress has to be considered as a confounder in studies measuring faecal glucocorticoid metabolites in cows to evaluate other stressful situations. © 2016 Blackwell Verlag GmbH.

Specific heats of lunar surface materials from 90 to 350 degrees Kelvin

USGS Publications Warehouse

Robie, R.A.; Hemingway, B.S.; Wilson, W.H.

1970-01-01

The specific heats of lunar samples 10057 and 10084 returned by the Apollo 11 mission have been measured between 90 and 350 degrees Kelvin by use of an adiabatic calorimeter. The samples are representative of type A vesicular basalt-like rocks and of finely divided lunar soil. The specific heat of these materials changes smoothly from about 0.06 calorie per gram per degree at 90 degrees Kelvin to about 0.2 calorie per gram per degree at 350 degrees Kelvin. The thermal parameter ??=(k??C)-1/2 for the lunar surface will accordingly vary by a factor of about 2 between lunar noon and midnight.

Near-term viability of solar heat applications for the federal sector

NASA Astrophysics Data System (ADS)

Williams, T. A.

1991-12-01

Solar thermal technologies are capable of providing heat across a wide range of temperatures, making them potentially attractive for meeting energy requirements for industrial process heat applications and institutional heating. The energy savings that could be realized by solar thermal heat are quite large, potentially several quads annually. Although technologies for delivering heat at temperatures above 100 C currently exist within industry, only a fairly small number of commercial systems have been installed to date. The objective of this paper is to investigate and discuss the prospects for near term solar heat sales to federal facilities as a mechanism for providing an early market niche to the aid the widespread development and implementation of the technology. The specific technical focus is on mid-temperature (100 to 350 C) heat demands that could be met with parabolic trough systems. Federal facilities have several features relative to private industry that may make them attractive for solar heat applications relative to other sectors. Key features are specific policy mandates for conserving energy, a long term planning horizon with well defined decision criteria, and prescribed economic return criteria for conservation and solar investments that are generally less stringent than the investment criteria used by private industry. Federal facilities also have specific difficulties in the sale of solar heat technologies that are different from those of other sectors, and strategies to mitigate these difficulties will be important. For the baseline scenario developed in this paper, the solar heat application was economically competitive with heat provided by natural gas. The system levelized energy cost was $5.9/MBtu for the solar heat case, compared to $6.8/MBtu for the life cycle fuel cost of a natural gas case. A third-party ownership would also be attractive to federal users, since it would guarantee energy savings and would not need initial federal funds.

On the existence of and mechanism for microwave-specific reaction rate enhancement† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc03372h Click here for additional data file.

PubMed Central

Dudley, Gregory B.; Richert, Ranko

2015-01-01

The use of microwave radiation to drive chemical reactions has become ubiquitous in almost all fields of chemistry. In all of these areas it is principally due to rapid and convenient heating resulting in significantly higher rates of reaction, with other advantages including enhanced product selectivity and control of materials properties. Although microwave heating continues to grow as an enabling technology, fundamental research into the nature of microwave heating has not grown at the same rate. In the case of chemical reactions run in homogeneous solution, particularly synthetic organic reactions, there is considerable controversy over the origins of rate enhancement, with a fundamental question being whether there exist microwave-specific effects, distinct from what can be attained under conventional convective heating, that can accelerate a reaction rate. In this Perspective, we discuss unique aspects of microwave heating of molecules in solution and discuss the origin and nature of microwave-specific effects arising from the process of “selective heating” of reactants in solution. Integral to this discussion is work from the field of dielectric relaxation spectroscopy, which provides a model for selective heating by Debye relaxation processes. The Perspective also includes a critical discussion of hypotheses of non-thermal effects (alternatively classified here as resonant processes) and an outline of specific reaction parameters for chemical systems in which microwave-specific Debye relaxation processes can result in observable reaction rate enhancement. PMID:29308138

Thermal inertia effect in an axisymmetric thermoelastic problem based on generalized thermoelasticity

NASA Astrophysics Data System (ADS)

Xie, Yushu; Li, Fatao

2010-06-01

The objective of this paper is to study thermal inertia effect due to the fact of the properties of the hyperbolic equations based on LS theory in generalized thermoelasticity. Simulations in a 2D hollow cylinder for uncoupled dynamic thermal stresses and thermal displacements were predicted by use of finite element method with Newmark algorithm. The thermal inertia effect on LS theory in rapid transient heat transfer process is also investigated in comparison with in steady heat transfer process. When different specific heat capacity is chosen, dynamic thermal stresses appear different types of vibration, in which less heat capacity causes more violent dynamic thermal stresses because of the thermal inertia effect. Both dynamic thermal stresses and thermal displacements in rapid transient heat transfer process have the larger amplitude and higher frequency than in steady heat transfer process due to thermal inertia from the results of simulation, which is consistent with the nature of the generalized thermoelasticity.

Design Development Analyses in Support of a Heatpipe-Brayton Cycle Heat Exchanger

NASA Technical Reports Server (NTRS)

Steeve, Brian; VanDyke, Melissa; Majumdar, Alok; Nguyen, Dalton; Corley, Melissa; Guffee, Ray M.; Kapernick, Richard J.

2003-01-01

One of the power systems under consideration for nuclear electric propulsion or as a planetary surface power source is a heatpipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heatpipes to the Brayton gas via a heat exchanger attached to the heatpipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at Marshall Space Flight Center. A companion paper, "Mechanical Design and Fabrication of a SAFE-100 Heat Exchanger for use in NASA s Advanced Propulsion Thermal-hydraulic Simulator", presents the fabrication issues and prototyping studies that, together with these analyses, led to the development of this heat exchanger. An important consideration throughout the design development of the heat exchanger was its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration.

Effectiveness of a multi-channel volumetric air receiver for a solar power tower

NASA Astrophysics Data System (ADS)

Jung, Eui Guk; Boo, Joon Hong; Kang, Yong Heak; Kim, Nak Hoon

2013-08-01

In this study, the heat transfer performance of a multi-channel volumetric air receiver for a solar power tower was numerically analyzed. The governing equations, including the solar radiation heat flux, conduction, convection and radiation heat transfer for a single channel, were solved on the basis of valid related references and a methodology that can predict the temperature distribution of the receiver wall and the heat transfer fluid for specific dimensions and input conditions. Furthermore, a mathematical model of the effectiveness of the receiver was derived from an analysis of the temperature profiles of the wall and the heat transfer fluid. The receiver effectiveness as an appropriate criterion to assess economic feasibility regarding geometric size was investigated, as it would be applied to the design process of the receiver. The main parameters for the thermal performance simulations described in this paper are the air mass flow rate, receiver length and the influence of these parameters on the heat transfer performance from the viewpoint of receiver efficiency and effectiveness.

Combustion performance and heat transfer characterization of LOX/hydrocarbon type propellants

NASA Technical Reports Server (NTRS)

Michel, R. W.

1983-01-01

An evaluation liquid oxygen (LOX) and various hydrocarbon fuels as low cost alternative propellants suitable for future space transportation system applications was done. The emphasis was directed toward low earth orbit maneuvering engine and reaction control engine systems. The feasibility of regeneratively cooling an orbit maneuvering thruster was analytically determined over a range of operating conditions from 100 to 1000 psia chamber pressure and 1000 to 10,000-1bF thrust, and specific design points were analyzed in detail for propane, methane, RP-1, ammonia, and ethanol; similar design point studies were performed for a film-cooled reaction control thruster. Heat transfer characteristics of propane were experimentally evaluated in heated tube tests. Forced convection heat transfer coefficients were determined. Seventy-seven hot firing tests were conducted with LOX/propane and LOX/ethanol, for a total duration of nearly 1400 seconds, using both heat sink and water-cooled calorimetric chambers. Combustion performance and stability and gas-side heat transfer characteristics were evaluated.

Waste Heat Approximation for Understanding Dynamic Compression in Nature and Experiments

NASA Astrophysics Data System (ADS)

Jeanloz, R.

2015-12-01

Energy dissipated during dynamic compression quantifies the residual heat left in a planet due to impact and accretion, as well as the deviation of a loading path from an ideal isentrope. Waste heat ignores the difference between the pressure-volume isentrope and Hugoniot in approximating the dissipated energy as the area between the Rayleigh line and Hugoniot (assumed given by a linear dependence of shock velocity on particle velocity). Strength and phase transformations are ignored: justifiably, when considering sufficiently high dynamic pressures and reversible transformations. Waste heat mis-estimates the dissipated energy by less than 10-20 percent for volume compressions under 30-60 percent. Specific waste heat (energy per mass) reaches 0.2-0.3 c02 at impact velocities 2-4 times the zero-pressure bulk sound velocity (c0), its maximum possible value being 0.5 c02. As larger impact velocities are implied for typical orbital velocities of Earth-like planets, and c02 ≈ 2-30 MJ/kg for rock, the specific waste heat due to accretion corresponds to temperature rises of about 3-15 x 103 K for rock: melting accompanies accretion even with only 20-30 percent waste heat retained. Impact sterilization is similarly quantified in terms of waste heat relative to the energy required to vaporize H2O (impact velocity of 7-8 km/s, or 4.5-5 c0, is sufficient). Waste heat also clarifies the relationship between shock, multi-shock and ramp loading experiments, as well as the effect of (static) pre-compression. Breaking a shock into 2 steps significantly reduces the dissipated energy, with minimum waste heat achieved for two equal volume compressions in succession. Breaking a shock into as few as 4 steps reduces the waste heat to within a few percent of zero, documenting how multi-shock loading approaches an isentrope. Pre-compression, being less dissipative than an initial shock to the same strain, further reduces waste heat. Multi-shock (i.e., high strain-rate) loading of pre-compressed samples may thus offer the closest approach to an isentrope, and therefore the most extreme compression at which matter can be studied at the "warm" temperatures of planetary interiors.

Increment of specific heat capacity of solar salt with SiO2 nanoparticles.

PubMed

Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J Enrique

2014-01-01

Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable. 65.: Thermal properties of condensed matter; 65.20.-w: Thermal properties of liquids; 65.20.Jk: Studies of thermodynamic properties of specific liquids.

Increment of specific heat capacity of solar salt with SiO2 nanoparticles

PubMed Central

2014-01-01

Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable. PACS 65.: Thermal properties of condensed matter; 65.20.-w: Thermal properties of liquids; 65.20.Jk: Studies of thermodynamic properties of specific liquids PMID:25346648

Study of performance degradation in Titanium microbolometer IR detectors due to elevated heating

NASA Astrophysics Data System (ADS)

Saxena, Raghvendra Sahai; Bhan, R. K.; Rana, Pratap Singh; Vishwakarma, A. K.; Aggarwal, Anita; Khurana, Kumkum; Gupta, Sudha

2011-07-01

Heating of thermal detectors is a major reliability concern because they are always subjected to heat whenever in operation and while absorbing excessive heat they may get degraded or damaged. In case of microbolometer Infrared (IR) detectors, heating can occur due to the absorbed radiations and also due to the bias current. In metal film microbolometers, wherein high bias current is supplied for improving responsivity, the bias heating is an issue. To study the effects of excessive heating of a Titanium microbolometer, we fabricated a linear array of such microbolometers and performed a destructive experiment of passing high bias current pulses through it and report here that even though the power supplied in pulse mode cannot damage the element physically, it may be sufficient for significant performance degradations. With this experiment we extracted that the maximum power that our Titanium microbolometer element can sustain without performance degradation is 2.25 mW. We have also reported a specific signature of temperature coefficient of resistance (TCR) that, up to the reported safe limit, remains almost constant and when that limit is crossed, reduces rapidly to a much lower value. If we keep increasing the power further it increases slightly and attains a kind of saturation.

Determination of Thermal State of Charge in Solar Heat Receivers

NASA Technical Reports Server (NTRS)

Glakpe, E. K.; Cannon, J. N.; Hall, C. A., III; Grimmett, I. W.

1996-01-01

The research project at Howard University seeks to develop analytical and numerical capabilities to study heat transfer and fluid flow characteristics, and the prediction of the performance of solar heat receivers for space applications. Specifically, the study seeks to elucidate the effects of internal and external thermal radiation, geometrical and applicable dimensionless parameters on the overall heat transfer in space solar heat receivers. Over the last year, a procedure for the characterization of the state-of-charge (SOC) in solar heat receivers for space applications has been developed. By identifying the various factors that affect the SOC, a dimensional analysis is performed resulting in a number of dimensionless groups of parameters. Although not accomplished during the first phase of the research, data generated from a thermal simulation program can be used to determine values of the dimensionless parameters and the state-of-charge and thereby obtain a correlation for the SOC. The simulation program selected for the purpose is HOTTube, a thermal numerical computer code based on a transient time-explicit, axisymmetric model of the total solar heat receiver. Simulation results obtained with the computer program are presented the minimum and maximum insolation orbits. In the absence of any validation of the code with experimental data, results from HOTTube appear reasonable qualitatively in representing the physical situations modeled.

Estimation of heat transfer coefficients for biomass particles by direct numerical simulation using microstructured particle models in the Laminar regime

DOE PAGES

Pecha, M. Brennan; Garcia-Perez, Manuel; Foust, Thomas D.; ...

2016-11-08

Here, direct numerical simulation of convective heat transfer from hot gas to isolated biomass particle models with realistic morphology and explicit microstructure was performed over a range of conditions with laminar flow of hot gas (500 degrees C). Steady-state results demonstrated that convective interfacial heat transfer is dependent on the wood species. The computed heat transfer coefficients were shown to vary between the pine and aspen models by nearly 20%. These differences are attributed to the species-specific variations in the exterior surface morphology of the biomass particles. We also quantify variations in heat transfer experienced by the particle when positionedmore » in different orientations with respect to the direction of fluid flow. These results are compared to previously reported heat transfer coefficient correlations in the range of 0.1 < Pr < 1.5 and 10 < Re < 500. Comparison of these simulation results to correlations commonly used in the literature (Gunn, Ranz-Marshall, and Bird-Stewart-Lightfoot) shows that the Ranz-Marshall (sphere) correlation gave the closest h values to our steady-state simulations for both wood species, though no existing correlation was within 20% of both species at all conditions studied. In general, this work exemplifies the fact that all biomass feedstocks are not created equal, and that their species-specific characteristics must be appreciated in order to facilitate accurate simulations of conversion processes.« less

Estimation of heat transfer coefficients for biomass particles by direct numerical simulation using microstructured particle models in the Laminar regime

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

Pecha, M. Brennan; Garcia-Perez, Manuel; Foust, Thomas D.

Here, direct numerical simulation of convective heat transfer from hot gas to isolated biomass particle models with realistic morphology and explicit microstructure was performed over a range of conditions with laminar flow of hot gas (500 degrees C). Steady-state results demonstrated that convective interfacial heat transfer is dependent on the wood species. The computed heat transfer coefficients were shown to vary between the pine and aspen models by nearly 20%. These differences are attributed to the species-specific variations in the exterior surface morphology of the biomass particles. We also quantify variations in heat transfer experienced by the particle when positionedmore » in different orientations with respect to the direction of fluid flow. These results are compared to previously reported heat transfer coefficient correlations in the range of 0.1 < Pr < 1.5 and 10 < Re < 500. Comparison of these simulation results to correlations commonly used in the literature (Gunn, Ranz-Marshall, and Bird-Stewart-Lightfoot) shows that the Ranz-Marshall (sphere) correlation gave the closest h values to our steady-state simulations for both wood species, though no existing correlation was within 20% of both species at all conditions studied. In general, this work exemplifies the fact that all biomass feedstocks are not created equal, and that their species-specific characteristics must be appreciated in order to facilitate accurate simulations of conversion processes.« less

Influence of heat transfer rates on pressurization of liquid/slush hydrogen propellant tanks

NASA Technical Reports Server (NTRS)

Sasmal, G. P.; Hochstein, J. I.; Hardy, T. L.

1993-01-01

A multi-dimensional computational model of the pressurization process in liquid/slush hydrogen tank is developed and used to study the influence of heat flux rates at the ullage boundaries on the process. The new model computes these rates and performs an energy balance for the tank wall whereas previous multi-dimensional models required a priori specification of the boundary heat flux rates. Analyses of both liquid hydrogen and slush hydrogen pressurization were performed to expose differences between the two processes. Graphical displays are presented to establish the dependence of pressurization time, pressurant mass required, and other parameters of interest on ullage boundary heat flux rates and pressurant mass flow rate. Detailed velocity fields and temperature distributions are presented for selected cases to further illuminate the details of the pressurization process. It is demonstrated that ullage boundary heat flux rates do significantly effect the pressurization process and that minimizing heat loss from the ullage and maximizing pressurant flow rate minimizes the mass of pressurant gas required to pressurize the tank. It is further demonstrated that proper dimensionless scaling of pressure and time permit all the pressure histories examined during this study to be displayed as a single curve.

Roto-chemical heating in a neutron star with fall-back disc accretion

NASA Astrophysics Data System (ADS)

Wei, Wei; Liu, Xi-Wei; Zheng, Xiao-Ping

2018-07-01

Recent research on the classical pulsar B0950+08 demonstrates that the explanation of its high surface temperature by roto-chemical heating encounters some difficulties. We assume that there is a fall-back disc around the newborn neutron star, which originates from the supernova ejecta and influences the spin and magnetic evolution of the star. By taking into account disc accretion and magnetic field evolution simultaneously, the effect of the fall-back disc accretion process on the roto-chemical heating in the neutron star is studied. The results show that there are two roto-chemical deviation phases (spin-up deviation and spin-down deviation), but that only the spin-down deviation leads to heating. The specific cooling curve depends on the accretion disc mass, the initial magnetic field and the magnetic field decay rate. Most importantly, the observations of surface temperature, magnetic field strength and spin period of the classical pulsar B0950+08 are well explained by the accretion roto-chemical heating model. The fall-back accretion process is important in roto-chemical heating for explanations of classical pulsars with high temperature. Given the absence of any evidence of fall-back accretion on to B0950+08, our study is purely hypothetical.

Prevalence of risk and protective factors associated with heat-related outcomes in Southern Quebec: A secondary analysis of the NuAge study.

PubMed

Laverdière, Émélie; Généreux, Mélissa; Gaudreau, Pierrette; Morais, José A; Shatenstein, Bryna; Payette, Hélène

2015-06-18

Heat vulnerability is increasing owing to climate change, aging and urbanization. This vulnerability may vary geographically. Our study examined the prevalence and distribution of risk and protective factors of heat-related outcomes among older adults across three health regions of Southern Quebec (Canada). This secondary cross-sectional study used data from the 1st follow-up of the NuAge longitudinal study, a cohort of community-dwelling older adults, aged 68-82 years at baseline, of three health regions: Eastern Townships, Montreal and Laval. Prevalence of factors, identified in Health Canada guidelines, was measured. An Older Adult Heat Vulnerability Index (OAHVI) simultaneously considering medical, social and environmental factors was constructed. The distribution of each factor and OAHVI was examined across the three regions. Results were weighted for age, sex (overall and region-specific analyses) and region (overall analyses). Ninety percent of participants had ≥1 risk factor, the most prevalent being: cardiovascular medication (50.8%), hypertension (46.7%), living alone (39.2%), cardiovascular disease (36.9%), living in an urban heat island (34.7%) and needing help in activities of daily living (26.5%). Two thirds of participants had ≥1 protective factor, the most prevalent being talking on the phone daily (70.9%). Heat vulnerability varied greatly by region and this variation was mainly attributable to social and environmental rather than medical factors. According to the OAHVI, 87.2% of participants cumulated ≥2 factors (median = 3.0 factors/participant). Our results support the need for small-scale assessment of heat vulnerability. This study could help stakeholders tackle heat-related illness and develop regionally tailored prevention programs.

Flow boiling with enhancement devices for cold plate coolant channel design

NASA Technical Reports Server (NTRS)

Boyd, Ronald D., Sr.

1989-01-01

A research program to study the effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly, is discussed. Freon 11 is the working fluid involved. The specific objectives are: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls, (2) examine the effect channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel, and (3) develop an improved data reduction analysis.

Reducing energy costs in nursing homes

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

Not Available

The handbook presents ideas and techniques for energy conservation in nursing homes. Case studies were developed of nursing homes located in different parts of the US. The typical nursing home assessed was proprietary, of intermediate-care level, medicaid-certified, and had less than 200 beds. Specific energy conservation measures were analyzed to determine the energy and dollar savings that could be realized. These include reducing heat loss through the building shell; reducing hot water costs; recovering the heat generated by dryers; reducing lighting costs; reducing heating and cooling costs, and analyzing fuels and fuel rates. A case for converting electric clothes dryersmore » to gas was analyzed. (MCW)« less

Design of a species-specific PCR method for the detection of the heat-resistant fungi Talaromyces macrosporus and Talaromyces trachyspermus.

PubMed

Yamashita, S; Nakagawa, H; Sakaguchi, T; Arima, T-H; Kikoku, Y

2018-01-01

Heat-resistant fungi occur sporadically and are a continuing problem for the food and beverage industry. The genus Talaromyces, as a typical fungus, is capable of producing the heat-resistant ascospores responsible for the spoilage of processed food products. Isocitrate lyase, a signature enzyme of the glyoxylate cycle, is required for the metabolism of non-fermentable carbon compounds, like acetate and ethanol. Here, species-specific primer sets for detection and identification of DNA derived from Talaromyces macrosporus and Talaromyces trachyspermus were designed based on the nucleotide sequences of their isocitrate lyase genes. Polymerase chain reaction (PCR) using a species-specific primer set amplified products specific to T. macrosporus and T. trachyspermus. Other fungal species, such as Byssochlamys fulva and Hamigera striata, which cause food spoilage, were not detected using the Talaromyces-specific primer sets. The detection limit for each species-specific primer set was determined as being 50 pg of template DNA, without using a nested PCR method. The specificity of each species-specific primer set was maintained in the presence of 1,000-fold amounts of genomic DNA from other fungi. The method also detected fungal DNA extracted from blueberry inoculated with T. macrosporus. This PCR method provides a quick, simple, powerful and reliable way to detect T. macrosporus and T. trachyspermus. Polymerase chain reaction (PCR)-based detection is rapid, convenient and sensitive compared with traditional methods of detecting heat-resistant fungi. In this study, a PCR-based method was developed for the detection and identification of amplification products from Talaromyces macrosporus and Talaromyces trachyspermus using primer sets that target the isocitrate lyase gene. This method could be used for the on-site detection of T. macrosporus and T. trachyspermus in the near future, and will be helpful in the safety control of raw materials and in food and beverage production. © 2017 The Authors. Letters in Applied Microbiology published by John Wiley & Sons Ltd on behalf of The Society for Applied Microbiology.

Measurement of the Specific Heat Using a Gravity Cancellation Approach

NASA Technical Reports Server (NTRS)

Zhong, Fang

2003-01-01

The specific heat at constant volume C(sob V) of a simple fluid diverges near its liquid-vapor critical point. However, gravity-induced density stratification due to the divergence of isothermal susceptibility hinders the direct comparison of the experimental data with the predictions of renormalization group theory. In the past, a microgravity environment has been considered essential to eliminate the density stratification. We propose to perform specific heat measurements of He-3 on the ground using a method to cancel the density stratification. A He-3 fluid layer will be heated from below, using the thermal expansion of the fluid to cancel the hydrostatic compression. A 6% density stratification at a reduced temperature of 10(exp -5) can be cancelled to better than 0.1% with a steady 1.7 micro K temperature difference across a 0.05 cm thick fluid layer. A conventional AC calorimetry technique will be used to determine the heat capacity. The minimized bulk density stratification with a relaxation time 6500 sec at a reduced temperature of 10(exp -5) will stay unchanged during 1 Hz AC heating. The smear of the specific heat divergence due to the temperature difference across the cell is about 0.1% at a reduced temperature of 10(exp -6). The combination of using High Resolution Thermometry with a 0.5 n K temperature resolution in the AC technique and the cancellation of the density stratification will enable C(sub V) to be measured down to a reduced temperature of 10(exp -6) with less than a 1% systematic error.

Social media responses to heat waves.

PubMed

Jung, Jihoon; Uejio, Christopher K

2017-07-01

Social network services (SNSs) may benefit public health by augmenting surveillance and distributing information to the public. In this study, we collected Twitter data focusing on six different heat-related themes (air conditioning, cooling center, dehydration, electrical outage, energy assistance, and heat) for 182 days from May 7 to November 3, 2014. First, exploratory linear regression associated outdoor heat exposure to the theme-specific tweet counts for five study cities (Los Angeles, New York, Chicago, Houston, and Atlanta). Next, autoregressive integrated moving average (ARIMA) time series models formally associated heat exposure to the combined count of heat and air conditioning tweets while controlling for temporal autocorrelation. Finally, we examined the spatial and temporal distribution of energy assistance and cooling center tweets. The result indicates that the number of tweets in most themes exhibited a significant positive relationship with maximum temperature. The ARIMA model results suggest that each city shows a slightly different relationship between heat exposure and the tweet count. A one-degree change in the temperature correspondingly increased the Box-Cox transformed tweets by 0.09 for Atlanta, 0.07 for Los Angeles, and 0.01 for New York City. The energy assistance and cooling center theme tweets suggest that only a few municipalities used Twitter for public service announcements. The timing of the energy assistance tweets suggests that most jurisdictions provide heating instead of cooling energy assistance.

Climate change and heat-related mortality in six cities Part 1: model construction and validation

NASA Astrophysics Data System (ADS)

Gosling, Simon N.; McGregor, Glenn R.; Páldy, Anna

2007-08-01

Heat waves are expected to increase in frequency and magnitude with climate change. The first part of a study to produce projections of the effect of future climate change on heat-related mortality is presented. Separate city-specific empirical statistical models that quantify significant relationships between summer daily maximum temperature ( T max) and daily heat-related deaths are constructed from historical data for six cities: Boston, Budapest, Dallas, Lisbon, London, and Sydney. ‘Threshold temperatures’ above which heat-related deaths begin to occur are identified. The results demonstrate significantly lower thresholds in ‘cooler’ cities exhibiting lower mean summer temperatures than in ‘warmer’ cities exhibiting higher mean summer temperatures. Analysis of individual ‘heat waves’ illustrates that a greater proportion of mortality is due to mortality displacement in cities with less sensitive temperature-mortality relationships than in those with more sensitive relationships, and that mortality displacement is no longer a feature more than 12 days after the end of the heat wave. Validation techniques through residual and correlation analyses of modelled and observed values and comparisons with other studies indicate that the observed temperature-mortality relationships are represented well by each of the models. The models can therefore be used with confidence to examine future heat-related deaths under various climate change scenarios for the respective cities (presented in Part 2).

Social media responses to heat waves

NASA Astrophysics Data System (ADS)

Jung, Jihoon; Uejio, Christopher K.

2017-07-01

Social network services (SNSs) may benefit public health by augmenting surveillance and distributing information to the public. In this study, we collected Twitter data focusing on six different heat-related themes (air conditioning, cooling center, dehydration, electrical outage, energy assistance, and heat) for 182 days from May 7 to November 3, 2014. First, exploratory linear regression associated outdoor heat exposure to the theme-specific tweet counts for five study cities (Los Angeles, New York, Chicago, Houston, and Atlanta). Next, autoregressive integrated moving average (ARIMA) time series models formally associated heat exposure to the combined count of heat and air conditioning tweets while controlling for temporal autocorrelation. Finally, we examined the spatial and temporal distribution of energy assistance and cooling center tweets. The result indicates that the number of tweets in most themes exhibited a significant positive relationship with maximum temperature. The ARIMA model results suggest that each city shows a slightly different relationship between heat exposure and the tweet count. A one-degree change in the temperature correspondingly increased the Box-Cox transformed tweets by 0.09 for Atlanta, 0.07 for Los Angeles, and 0.01 for New York City. The energy assistance and cooling center theme tweets suggest that only a few municipalities used Twitter for public service announcements. The timing of the energy assistance tweets suggests that most jurisdictions provide heating instead of cooling energy assistance.

Ab-initio study of thermodynamic properties of boron nanowire at atomic scale

NASA Astrophysics Data System (ADS)

Bhuyan, Prabal D.; Gupta, Sanjeev K.; Sonvane, Y.; Gajjar, P. N.

2018-04-01

In the present work, we have optimized ribbon like zigzag structure of boron (B) nanowire (NW) and investigated vibrational and thermodynamic properties using quasi-harmonic approximations (QHA). All positive phonon in the phonon dispersive curve have confirmed dynamical stability of ribbon B-NW. The thermodynamic properties, like Debye temperature, internal energy and specific heat, are calculated as a function of temperature. The variation of specific heat is proportional to T3 Debye law at lower temperature for B-NW, while it becomes constant above room temperature at 1200K; obeys Dulong-Petit's law. The high Debye temperature of 1120K is observed at ambient temperature, which can be attributed to high thermal conductivity. Our study shows that B-NW with high thermal conductivity could be the next generation electron connector for nanoscale electronic devices.

The near-term hybrid vehicle program, phase 1

NASA Technical Reports Server (NTRS)

1979-01-01

Performance specifications were determined for a hybrid vehicle designed to achieve the greatest reduction in fuel consumption. Based on the results of systems level studies, a baseline vehicle was constructed with the following basic paramaters: a heat engine power peak of 53 kW (VW gasoline engine); a traction motor power peak of 30 kW (Siemens 1GV1, separately excited); a heat engine fraction of 0.64; a vehicle curb weight of 2080 kg; a lead acid battery (35 kg weight); and a battery weight fraction of 0.17. The heat engine and the traction motor are coupled together with their combined output driving a 3 speed automatic transmission with lockup torque converter. The heat engine is equipped withe a clutch which allows it to be decoupled from the system.

Prototype solar heating and hot water systems

NASA Technical Reports Server (NTRS)

1977-01-01

Alternative approaches to solar heating and hot water system configurations were studied, parametrizing the number and location of the dampers, the number and location of the fans, the interface locations with the furnace, the size and type of subsystems, and operating modes. A two-pass air-heating collector was selected based on efficiency and ease of installation. Also, an energy transport module was designed to compactly contain all the mechanical and electrical control components. System performance calculations were carried out over a heating season for the tentative site location at Tunkhnana, Pa. Results illustrate the effect of collector size, storage capacity, and use of a reflector. Factors which affected system performance include site location, insulative quality of the house, and of the system components. A preliminary system performance specification is given.

Genome scale transcriptional response diversity among ten ecotypes of Arabidopsis thaliana during heat stress

PubMed Central

Barah, Pankaj; Jayavelu, Naresh D.; Mundy, John; Bones, Atle M.

2013-01-01

In the scenario of global warming and climate change, heat stress is a serious threat to crop production worldwide. Being sessile, plants cannot escape from heat. Plants have developed various adaptive mechanisms to survive heat stress. Several studies have focused on diversity of heat tolerance levels in divergent Arabidopsis thaliana (A. thaliana) ecotypes, but comprehensive genome scale understanding of heat stress response in plants is still lacking. Here we report the genome scale transcript responses to heat stress of 10 A. thaliana ecotypes (Col, Ler, C24, Cvi, Kas1, An1, Sha, Kyo2, Eri, and Kond) originated from different geographical locations. During the experiment, A. thaliana plants were subjected to heat stress (38°C) and transcript responses were monitored using Arabidopsis NimbleGen ATH6 microarrays. The responses of A. thaliana ecotypes exhibited considerable variation in the transcript abundance levels. In total, 3644 transcripts were significantly heat regulated (p < 0.01) in the 10 ecotypes, including 244 transcription factors and 203 transposable elements. By employing a systems genetics approach- Network Component Analysis (NCA), we have constructed an in silico transcript regulatory network model for 35 heat responsive transcription factors during cellular responses to heat stress in A. thaliana. The computed activities of the 35 transcription factors showed ecotype specific responses to the heat treatment. PMID:24409190

Experimental determination of in situ utilization of lunar regolith for thermal energy storage

NASA Technical Reports Server (NTRS)

Richter, Scott W.

1992-01-01

A Lunar Thermal Energy from Regolith (LUTHER) experiment has been designed and fabricated at the NASA Lewis Research Center to determine the feasibility of using lunar soil as thermal energy storage media. The experimental apparatus includes an alumina ceramic canister which contains simulated lunar regolith, a heater, nine heat shields, a heat transfer cold jacket, and 19 type-B platinum rhodium thermocouples. The simulated lunar regolith is a basalt that closely resembles the lunar basalt returned to earth by the Apollo missions. The experiment will test the effects of vacuum, particle size, and density on the thermophysical properties of the regolith, which include melt temperature, specific heat thermal conductivity, and latent heat of storage. Two separate tests, using two different heaters, will be performed to study the effect of heating the system using radiative and conductive heat transfer. A finite differencing SINDA model was developed at NASA Lewis Research Center to predict the performance of the LUTHER experiment. The code will predict the effects of vacuum, particle size, and density has on the heat transfer to the simulated regolith.

Review of heat transfer problems associated with magnetically-confined fusion reactor concepts

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

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

1976-04-01

Conceptual design studies of possible fusion reactor configurations have revealed a host of interesting and sometimes extremely difficult heat transfer problems. The general requirements imposed on the coolant system for heat removal of the thermonuclear power from the reactor are discussed. In particular, the constraints imposed by the fusion plasma, neutronics, structure and magnetic field environment are described with emphasis on those aspects which are unusual or unique to fusion reactors. Then the particular heat transfer characteristics of various possible coolants including lithium, flibe, boiling alkali metals, and helium are discussed in the context of these general fusion reactor requirements.more » Some specific areas where further experimental and/or theoretical work is necessary are listed for each coolant along with references to the pertinent research already accomplished. Specialized heat transfer problems of the plasma injection and removal systems are also described. Finally, the challenging heat transfer problems associated with the superconducting magnets are reviewed, and once again some of the key unsolved heat transfer problems are enumerated.« less

Heat stress management program improving worker health and operational effectiveness: a case study.

PubMed

Huss, Rosalyn G; Skelton, Scott B; Alvis, Kimberly L; Shane, Leigh A

2013-03-01

Heat stress monitoring is a vital component of an effective health and safety program when employees work in exceptionally warm environments. Workers at hazardous waste sites often wear personal protective equipment (PPE), which increases the body heat stress load. No specific Occupational Safety and Health Administration (OSHA) regulations address heat stress; however, OSHA does provide several guidance documents to assist employers in addressing this serious workplace health hazard. This article describes a heat stress and surveillance plan implemented at a hazardous waste site as part of the overall health and safety program. The PPE requirement for work at this site, coupled with extreme environmental temperatures, made heat stress a significant concern. Occupational health nurses and industrial hygienists developed a monitoring program for heat stress designed to prevent the occurrence of significant heat-related illness in site workers. The program included worker education on the signs of heat-related illness and continuous physiologic monitoring to detect early signs of heat-related health problems. Biological monitoring data were collected before workers entered the exclusion zone and on exiting the zone following decontamination. Sixty-six site workers were monitored throughout site remediation. More than 1,700 biological monitoring data points were recorded. Outcomes included improved worker health and safety, and increased operational effectiveness. Copyright 2013, SLACK Incorporated.

The Rapid-Heat LAMPellet Method: A Potential Diagnostic Method for Human Urogenital Schistosomiasis

PubMed Central

Carranza-Rodríguez, Cristina; Pérez-Arellano, José Luis; Vicente, Belén; López-Abán, Julio; Muro, Antonio

2015-01-01

Background Urogenital schistosomiasis due to Schistosoma haematobium is a serious underestimated public health problem affecting 112 million people - particularly in sub-Saharan Africa. Microscopic examination of urine samples to detect parasite eggs still remains as definitive diagnosis. This work was focussed on developing a novel loop-mediated isothermal amplification (LAMP) assay for detection of S. haematobium DNA in human urine samples as a high-throughput, simple, accurate and affordable diagnostic tool to use in diagnosis of urogenital schistosomiasis. Methodology/Principal Findings A LAMP assay targeting a species specific sequence of S. haematobium ribosomal intergenic spacer was designed. The effectiveness of our LAMP was assessed in a number of patients´ urine samples with microscopy confirmed S. haematobium infection. For potentially large-scale application in field conditions, different DNA extraction methods, including a commercial kit, a modified NaOH extraction method and a rapid heating method were tested using small volumes of urine fractions (whole urine, supernatants and pellets). The heating of pellets from clinical samples was the most efficient method to obtain good-quality DNA detectable by LAMP. The detection limit of our LAMP was 1 fg/µL of S. haematobium DNA in urine samples. When testing all patients´ urine samples included in our study, diagnostic parameters for sensitivity and specificity were calculated for LAMP assay, 100% sensitivity (95% CI: 81.32%-100%) and 86.67% specificity (95% CI: 75.40%-94.05%), and also for microscopy detection of eggs in urine samples, 69.23% sensitivity (95% CI: 48.21% -85.63%) and 100% specificity (95% CI: 93.08%-100%). Conclusions/Significance We have developed and evaluated, for the first time, a LAMP assay for detection of S. haematobium DNA in heated pellets from patients´ urine samples using no complicated requirement procedure for DNA extraction. The procedure has been named the Rapid-Heat LAMPellet method and has the potential to be developed further as a field diagnostic tool for use in urogenital schistosomiasis-endemic areas. PMID:26230990

Take the HEAT: A pilot study on improving communication with angry families.

PubMed

Delacruz, Nicolas; Reed, Suzanne; Splinter, Ansley; Brown, Amy; Flowers, Stacy; Verbeck, Nicole; Turpening, Debbie; Mahan, John D

2017-06-01

Our objective was to evaluate the utility of an educational program consisting of a workshop based on the Take the HEAT communication strategy, designed specifically for addressing patients who are angry, using a novel tool to evaluate residents' skills in employing this method. 33 first-year pediatric and internal medicine-pediatrics residents participated in the study. The workshop presented the Take the HEAT (Hear, Empathize, Apologize, Take action) strategy of communication. Communication skills were assessed through standardized patient encounters at baseline and post-workshop. Encounters were scored using a novel assessment tool. After the workshop, residents' Take the HEAT communication improved from baseline total average score 23.15 to total average score 25.36 (Z=-3.428, p<0.001). At baseline, empathy skills were the lowest. Intraclass Correlation Coefficient demonstrated substantial agreement (0.60 and 0.61) among raters using the tool. First-year pediatric trainees' communication with angry families improved with education focused on the Take the HEAT strategy. Poor performance by residents in demonstrating empathy should be explored further. This study demonstrates the utility of a brief communications curriculum aimed at improving pediatric residents' ability to communicate with angry families. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Study of advanced fuel system concepts for commercial aircraft

NASA Technical Reports Server (NTRS)

Coffinberry, G. A.

1985-01-01

An analytical study was performed in order to assess relative performance and economic factors involved with alternative advanced fuel systems for future commercial aircraft operating with broadened property fuels. The DC-10-30 wide-body tri-jet aircraft and the CF6-8OX engine were used as a baseline design for the study. Three advanced systems were considered and were specifically aimed at addressing freezing point, thermal stability and lubricity fuel properties. Actual DC-10-30 routes and flight profiles were simulated by computer modeling and resulted in prediction of aircraft and engine fuel system temperatures during a nominal flight and during statistical one-day-per-year cold and hot flights. Emergency conditions were also evaluated. Fuel consumption and weight and power extraction results were obtained. An economic analysis was performed for new aircraft and systems. Advanced system means for fuel tank heating included fuel recirculation loops using engine lube heat and generator heat. Environmental control system bleed air heat was used for tank heating in a water recirculation loop. The results showed that fundamentally all of the three advanced systems are feasible but vary in their degree of compatibility with broadened-property fuel.

Simultaneous measurement for thermal conductivity, diffusivity, and specific heat of methane hydrate bearing sediments recovered from Nankai-Trough wells

NASA Astrophysics Data System (ADS)

Muraoka, M.; Ohtake, M.; Susuki, N.; Yamamoto, Y.; Suzuki, K.; Tsuji, T.

2014-12-01

This study presents the results of the measurements of the thermal constants of natural methane-hydrate-bearing sediments samples recovered from the Tokai-oki test wells (Nankai-Trough, Japan) in 2004. The thermal conductivity, thermal diffusivity, and specific heat of the samples were simultaneously determined using the hot-disk transient method. The thermal conductivity of natural hydrate-bearing sediments decreases slightly with increasing porosity. In addition, the thermal diffusivity of hydrate-bearing sediment decrease as porosity increases. We also used simple models to calculate the thermal conductivity and thermal diffusivity. The results of the distribution model (geometric-mean model) are relatively consistent with the measurement results. In addition, the measurement results are consistent with the thermal diffusivity, which is estimated by dividing the thermal conductivity obtained from the distribution model by the specific heat obtained from the arithmetic mean. In addition, we discuss the relation between the thermal conductivity and mineral composition of core samples in conference. Acknowledgments. This work was financially supported by MH21 Research Consortium for Methane Hydrate Resources in Japan on the National Methane Hydrate Exploitation Program planned by the Ministry of Economy, Trade and Industry.

49 CFR 179.300-10 - Postweld heat treatment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Postweld heat treatment. 179.300-10 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-10 Postweld heat treatment. After welding is complete, steel tanks and all attachments welded thereto, must be postweld heat treated...

49 CFR 179.300-10 - Postweld heat treatment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Postweld heat treatment. 179.300-10 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-10 Postweld heat treatment. After welding is complete, steel tanks and all attachments welded thereto, must be postweld heat treated...

Nanofluids for power engineering: Emergency cooling of overheated heat transfer surfaces

NASA Astrophysics Data System (ADS)

Bondarenko, B. I.; Moraru, V. N.; Sidorenko, S. V.; Komysh, D. V.

2016-07-01

The possibility of emergency cooling of an overheated heat transfer surface using nanofluids in the case of a boiling crisis is explored by means of synchronous recording of changes of main heat transfer parameters of boiling water over time. Two nanofluids are tested, which are derived from a mixture of natural aluminosilicates (AlSi-7) and titanium dioxide (NF-8). It is found that the introduction of a small portions of nanofluid into a boiling coolant (distilled water) in a state of film boiling ( t heater > 500°C) can dramatically decrease the heat transfer surface temperature to 130-150°C, which corresponds to a transition to a safe nucleate boiling regime without affecting the specific heat flux. The fact that this regime is kept for a long time at a specific heat load exceeding the critical heat flux for water and t heater = 125-130°C is particularly important. This makes it possible to prevent a potential accident emergency (heater burnout and failure of the heat exchanger) and to ensure the smooth operation of the equipment.

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Thermophysical Properties of Solid and Liquid Ti-6Al-4V (TA6V) Alloy

NASA Astrophysics Data System (ADS)

Boivineau, M.; Cagran, C.; Doytier, D.; Eyraud, V.; Nadal, M.-H.; Wilthan, B.; Pottlacher, G.

2006-03-01

Ti-6Al-4V (TA6V) titanium alloy is widely used in industrial applications such as aeronautic and aerospace due to its good mechanical properties at high temperatures. Experiments on two different resistive pulse heating devices (CEA Valduc and TU-Graz) have been carried out in order to study thermophysical properties (such as electrical resistivity, volume expansion, heat of fusion, heat capacity, normal spectral emissivity, thermal diffusivity, and thermal conductivity) of both solid and liquid Ti-6Al-4V. Fast time-resolved measurements of current, voltage, and surface radiation and shadowgraphs of the volume have been undertaken. At TU-Graz, a fast laser polarimeter has been used for determining the emissivity of liquid Ti-6Al-4V at 684.5 nm and a differential scanning calorimeter (DSC) for measuring the heat capacity of solid Ti-6Al-4V. This study deals with the specific behavior of the different solid phase transitions (effect of heating rate) and the melting region, and emphasizes the liquid state ( T > 2000 K).

Analysis of Protein–Protein Interactions in MCF-7 and MDA-MB-231 Cell Lines Using Phthalic Acid Chemical Probes

PubMed Central

Liang, Shih-Shin; Wang, Tsu-Nai; Tsai, Eing-Mei

2014-01-01

Phthalates are a class of plasticizers that have been characterized as endocrine disrupters, and are associated with genital diseases, cardiotoxicity, hepatotoxicity, and nephrotoxicity in the GeneOntology gene/protein database. In this study, we synthesized phthalic acid chemical probes and demonstrated differing protein–protein interactions between MCF-7 cells and MDA-MB-231 breast cancer cell lines. Phthalic acid chemical probes were synthesized using silicon dioxide particle carriers, which were modified using the silanized linker 3-aminopropyl triethoxyslane (APTES). Incubation with cell lysates from breast cancer cell lines revealed interactions between phthalic acid and cellular proteins in MCF-7 and MDA-MB-231 cells. Subsequent proteomics analyses indicated 22 phthalic acid-binding proteins in both cell types, including heat shock cognate 71-kDa protein, ATP synthase subunit beta, and heat shock protein HSP 90-beta. In addition, 21 MCF-7-specific and 32 MDA-MB-231 specific phthalic acid-binding proteins were identified, including related proteasome proteins, heat shock 70-kDa protein, and NADPH dehydrogenase and ribosomal correlated proteins, ras-related proteins, and members of the heat shock protein family, respectively. PMID:25402641

Experimental approach for thermal parameters estimation during glass forming process

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

Stability Projections for High Temperature Superconductors

DTIC Science & Technology

1990-03-01

able data or our best estimates. 2.2.1. Specific Heat per Unit Volume - From the specific heat measurements of Junod et al. [5] and Inderhees et aL...for 77-K Super- conducting Magnets, IEEE Trans. MAG 24, 1211-14 (1988). [5] Junod , Bezinge et XVI al., Structure, Resistivity, Criti- cal Field

49 CFR 178.348-4 - Pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... = The latent heat of vaporization of the lading—calories per gram (BTU/lb); Z = The compressibility... maximum loading and unloading rates must be included on the metal specification plate. (3) Cargo tanks... = A constant derived from (K), the ratio of specific heats of the vapor. If (K) is unknown, let C...

Low temperature heat capacity of permanently densified SiO2 glasses

NASA Astrophysics Data System (ADS)

Carini, Giovanni; Carini, Giuseppe; Cosio, Daniele; D'Angelo, Giovanna; Rossi, Flavio

2016-03-01

A study of low temperature specific heat capacity (1-30 K) has been performed on samples of vitreous SiO2, which have been compacted under pressures up to 8 GPa to explore different glassy phases having growing density. Increasing densification by more than 21% leads to a progressive reduction of the specific heat capacity Cp and to a shift from 10 K up to about 17 K of the broad hump, the calorimetric Boson peak (BP), observed above 1 K in a Cp(T)/T3 vs. T plot. The revealed changes are not accounted for by the modifications of the elastic continuum, implying a nature of additional vibrations at variance with the extended sound waves. Increasing atomic packing of the glassy network leads to a progressively decreasing excess heat capacity over that of α-quartz, a crystalline polymorph of SiO2. By using the low-frequency Raman intensity measured in these glasses to determine the temperature dependence of the low temperature heat capacity, it has been evaluated the density of low-frequency vibrational states. The observations are compared with some theoretical pictures explaining the nature of the BP, disclosing qualitative agreement with the predictions of the Soft Potential Model and the results of a simulation study concerning the vibrations of jammed particles. This finding leads to evaluate a nanometer length scale which suggests the existence of poorly packed domains formed from several n-membered rings involving SiO4 tetrahedra. These soft regions are believed to be the main source of low-frequency vibrations giving rise to the BP.

Transcriptomic characterization of temperature stress responses in larval zebrafish.

PubMed

Long, Yong; Li, Linchun; Li, Qing; He, Xiaozhen; Cui, Zongbin

2012-01-01

Temperature influences nearly all biochemical, physiological and life history activities of fish, but the molecular mechanisms underlying the temperature acclimation remains largely unknown. Previous studies have identified many temperature-regulated genes in adult tissues; however, the transcriptional responses of fish larvae to temperature stress are not well understood. In this study, we characterized the transcriptional responses in larval zebrafish exposed to cold or heat stress using microarray analysis. In comparison with genes expressed in the control at 28 °C, a total of 2680 genes were found to be affected in 96 hpf larvae exposed to cold (16 °C) or heat (34 °C) for 2 and 48h and most of these genes were expressed in a temperature-specific and temporally regulated manner. Bioinformatic analysis identified multiple temperature-regulated biological processes and pathways. Biological processes overrepresented among the earliest genes induced by temperature stress include regulation of transcription, nucleosome assembly, chromatin organization and protein folding. However, processes such as RNA processing, cellular metal ion homeostasis and protein transport and were enriched in genes up-regulated under cold exposure for 48 h. Pathways such as mTOR signalling, p53 signalling and circadian rhythm were enriched among cold-induced genes, while adipocytokine signalling, protein export and arginine and praline metabolism were enriched among heat-induced genes. Although most of these biological processes and pathways were specifically regulated by cold or heat, common responses to both cold and heat stresses were also found. Thus, these findings provide new interesting clues for elucidation of mechanisms underlying the temperature acclimation in fish.

Antarctic marine molluscs do have an HSP70 heat shock response.

PubMed

Clark, Melody S; Fraser, Keiron P P; Peck, Lloyd S

2008-01-01

The success of any organism depends not only on niche adaptation but also the ability to survive environmental perturbation from homeostasis, a situation generically described as stress. Although species-specific mechanisms to combat "stress" have been described, the production of heat shock proteins (HSPs), such as HSP70, is universally described across all taxa. Members of the HSP70 gene family comprising the constitutive (HSC70) and inducible (HSP70) members, plus GRP78 (glucose-regulated protein, 78 kDa), a related HSP70 family member, were cloned using degenerate polymerase chain reaction (PCR) from two evolutionary divergent Antarctic marine molluscs (Laternula elliptica and Nacella concinna), a bivalve and a gastropod, respectively. The expression of the HSP70 family members was surveyed via quantitative PCR after an acute 2-h heat shock experiment. Both species demonstrated significant up-regulation of HSP70 gene expression in response to increased temperatures. However, the temperature level at which these responses were induced varied with the species (+6-8 degrees C for L. elliptica and +8-10 degrees C for N. concinna) compared to their natural environmental temperature). L. elliptica also showed tissue-specific expression of the genes under study. Previous work on Antarctic fish has shown that they lack the classical heat shock response, with the inducible form of HSP70 being permanently expressed with an expression not further induced under higher temperature regimes. This study shows that this is not the case for other Antarctic animals, with the two molluscs showing an inducible heat shock response, at a level probably set during their temperate evolutionary past.

Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima” and “Cucurbita moschata”) and Their Interspecific Inbred Line “Maxchata”

PubMed Central

Ara, Neelam; Nakkanong, Korakot; Lv, Wenhui; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang

2013-01-01

The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2), superoxide (O2−) and malondialdehyde (MDA) contents in the roots compared to stems, followed by “Maxchata”. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima” and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration. PMID:24336062

Heated Ultrasound Gel and Patient Satisfaction with Bedside Ultrasound Studies: The HUGS Trial

PubMed Central

Krainin, Benjamin M.; Thaut, Lane C.; April, Michael D.; Curtis, Ryan A.; Kaelin, Andrea L.; Hardy, Garrett B.; Weymouth, Wells L.; Srichandra, Jonathan; Chin, Eric J.; Summers, Shane M.

2017-01-01

Introduction Our goal was to determine if heated gel for emergency department (ED) bedside ultrasonography improves patient satisfaction compared to room-temperature gel. Methods We randomized a convenience sample of ED patients determined by their treating physician to require a bedside ultrasound (US) study to either heated gel (102.0° F) or room-temperature gel (82.3° F). Investigators performed all US examinations. We informed all subjects that the study entailed investigation into various measures to improve patient satisfaction with ED US examinations but did not inform them of our specific focus on gel temperature. Investigators wore heat-resistant gloves while performing the examinations to blind themselves to the gel temperature. After completion of the US, subjects completed a survey including the primary outcome measure of patient satisfaction as measured on a 100-mm visual analogue scale (VAS). A secondary outcome was patient perceptions of sonographer professionalism measured by an ordinal scale (1–5). Results We enrolled 124 subjects; 120 completed all outcome measures. Of these, 59 underwent randomization to US studies with room-temperature gel and 61 underwent randomization to heated US gel. Patient 100-mm VAS satisfaction scores were 83.9 among patients undergoing studies with room-temperature gel versus 87.6 among subjects undergoing studies with heated gel (effect size 3.7, 95% confidence interval −1.3–8.6). There were similarly no differences between the two arms with regard to patient perceptions of sonographer professionalism. Conclusion The use of heated ultrasound gel appears to have no material impact on the satisfaction of ED patients undergoing bedside ultrasound studies. PMID:29085538

Deuterium and lithium-6 MAS NMR studies of manganese oxide electrode materials

NASA Astrophysics Data System (ADS)

Paik, Younkee

Electrolytic manganese dioxide (EMD) is used world wide as the cathode materials in both lithium and alkaline primary (non-rechargeable) batteries. We have developed deuterium and lithium MAS NMR techniques to study EMD and related manganese oxides and hydroxides, where diffraction techniques are of limited value due to a highly defective nature of the structures. Deuterons in EMD, manganite, groutite, and deuterium-intercalated pyrolusite and ramsdellite were detected by NMR, for the first time, and their locations and motions in the structures were analyzed by applying variable temperature NMR techniques. Discharge mechanisms of EMD in alkaline (aqueous) electrolytes were studied, in conjunction with step potential electrochemical spectroscopic (SPECS) method, and five distinctive discharge processes were proposed. EMD is usually heat-treated at about 300--400°C to remove water to be used in lithium batteries. Details of the effects of heat-treatment, such as structural and compositional changes as a function of heat-treatment temperature, were studied by a combination of MAS NMR, XRD, and thermogravimetric analysis. Lithium local environments in heat-treated EMD (HEMD) that were discharged in lithium cells, were described in terms of related environments found in model compounds pyrolusite and ramsdellite where specific Li + sites were detected by MAS NMR and the hyperfine shift scale method of Grey et al. Acid-leaching of Li2MnO3 represents an approach for synthesizing new or modified manganese oxide electrode materials for lithium rechargeable batteries. Progressive removal of lithium from specific crystallographic sites, followed by a gradual change of the crystal structure, was monitored by a combination of NMR and XRD techniques.

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.

Investigation and optimization of the depth of flue gas heat recovery in surface heat exchangers

NASA Astrophysics Data System (ADS)

Bespalov, V. V.; Bespalov, V. I.; Melnikov, D. V.

2017-09-01

Economic issues associated with designing deep flue gas heat recovery units for natural gas-fired boilers are examined. The governing parameter affecting the performance and cost of surface-type condensing heat recovery heat exchangers is the heat transfer surface area. When firing natural gas, the heat recovery depth depends on the flue gas temperature at the condenser outlet and determines the amount of condensed water vapor. The effect of the outlet flue gas temperature in a heat recovery heat exchanger on the additionally recovered heat power is studied. A correlation has been derived enabling one to determine the best heat recovery depth (or the final cooling temperature) maximizing the anticipated reduced annual profit of a power enterprise from implementation of energy-saving measures. Results of optimization are presented for a surface-type condensing gas-air plate heat recovery heat exchanger for the climatic conditions and the economic situation in Tomsk. The predictions demonstrate that it is economically feasible to design similar heat recovery heat exchangers for a flue gas outlet temperature of 10°C. In this case, the payback period for the investment in the heat recovery heat exchanger will be 1.5 years. The effect of various factors on the optimal outlet flue gas temperature was analyzed. Most climatic, economical, or technological factors have a minor effect on the best outlet temperature, which remains between 5 and 20°C when varying the affecting factors. The derived correlation enables us to preliminary estimate the outlet (final) flue gas temperature that should be used in designing the heat transfer surface of a heat recovery heat exchanger for a gas-fired boiler as applied to the specific climatic conditions.

Heat shock proteins and toll-like receptors.

PubMed

Asea, Alexzander

2008-01-01

Researchers have only just begun to elucidate the relationship between heat shock proteins (HSP) and Toll-like receptors (TLR). HSP were originally described as an intracellular molecular chaperone of naïve, aberrantly folded, or mutated proteins and primarily implicated as a cytoprotective protein when cells are exposed to stressful stimuli. However, recent studies have ascribed novel functions to the Hsp70 protein depending on its localization: Surface-bound Hsp70 specifically activate natural killer (NK) cells, while Hsp70 released into the extracellular milieu specifically bind to Toll-like receptors (TLR) 2 and 4 on antigen-presenting cells (APC) and exerts immunoregulatory effects, including upregulation of adhesion molecules, co-stimulatory molecule expression, and cytokine and chemokine release-a process known as the chaperokine activity of Hsp70. This chapter discusses the most recent advances in the understanding of heat shock protein (HSP) and TLR interactions in general and highlights recent findings that demonstrate Hsp70 is a ligand for TLR and its biological significance.

Characteristics of turbulence transport for momentum and heat in particle-laden turbulent vertical channel flows

NASA Astrophysics Data System (ADS)

Liu, Caixi; Tang, Shuai; Shen, Lian; Dong, Yuhong

2017-10-01

The dynamic and thermal performance of particle-laden turbulent flow is investigated via direction numerical simulation combined with the Lagrangian point-particle tracking under the condition of two-way coupling, with a focus on the contributions of particle feedback effect to momentum and heat transfer of turbulence. We take into account the effects of particles on flow drag and Nusselt number and explore the possibility of drag reduction in conjunction with heat transfer enhancement in particle-laden turbulent flows. The effects of particles on momentum and heat transfer are analyzed, and the possibility of drag reduction in conjunction with heat transfer enhancement for the prototypical case of particle-laden turbulent channel flows is addressed. We present results of turbulence modification and heat transfer in turbulent particle-laden channel flow, which shows the heat transfer reduction when large inertial particles with low specific heat capacity are added to the flow. However, we also found an enhancement of the heat transfer and a small reduction of the flow drag when particles with high specific heat capacity are involved. The present results show that particles, which are active agents, interact not only with the velocity field, but also the temperature field and can cause a dissimilarity in momentum and heat transport. This demonstrates that the possibility to increase heat transfer and suppress friction drag can be achieved with addition of particles with different thermal properties.

Heat-pump-centered integrated community energy systems: Systems development, Consolidated Natural Gas Service Company

NASA Astrophysics Data System (ADS)

Baker, N. R.; Donakowski, T. D.; Foster, R. B.; Sala, D. L.; Tison, R. R.; Whaley, T. P.; Yudow, B. D.; Swenson, P. F.

1980-01-01

The heat actuated heat pump centered integrated community energy system (HAHP-ICES) is described. The system utilizes a gas fired, engine-driven, heat pump and commercial buildings, and offers several advantages over the more conventional equipment it is intended to supplant. The general nonsite specific application assumes a hypothetical community of one 59,000 cu ft office building and five 24 unit, low rise apartment buildings located in a region with a climate similar to Chicago. Various sensitivity analyses are performed and through which the performance characteristics of the HAHP are explored. The results provided the selection criteria for the site specific application of the HAHP-ICES concept to a real world community. The site-specific community consists of: 42 town houses; five 120 unit, low rise apartment buildings; five 104 unit high rise apartment buildings; one 124,000 cu ft office building; and a single 135,000 cu ft retail building.

Urban heat islands in the subsurface of German cities

NASA Astrophysics Data System (ADS)

Menberg, K.; Blum, P.; Zhu, K.; Bayer, P.

2012-04-01

In the subsurface of many cities there are widespread and persistent thermal anomalies (subsurface urban heat islands) that result in a warming of urban aquifers. The reasons for this heating are manifold. Possible heat sources are basements of buildings, leakage of sewage systems, buried district heating networks, re-injection of cooling water and solar irradiation on paved surfaces. In the current study, the reported groundwater temperatures in several German cities, such as Berlin, Munich, Cologne and Karlsruhe, are compared. Available data sets are supplemented by temperature measurements and depth profiles in observation wells. Trend analyses are conducted with time series of groundwater temperatures, and three-dimensional groundwater temperature maps are provided. In all investigated cities, pronounced positive temperature anomalies are present. The distribution of groundwater temperatures appears to be spatially and temporally highly variable. Apparently, the increased heat input into the urban subsurface is controlled by very local and site-specific parameters. In the long-run, the superposition of various heat sources results in an extensive temperature increase. In many cases, the maximum temperature elevation is found close to the city centre. Regional groundwater temperature differences between the city centre and the rural background are up to 5 °C, with local hot spots of even more pronounced anomalies. Particular heat sources, like cooling water injections or case-specific underground constructions, can cause local temperatures > 20°C in the subsurface. Examination of the long-term variations in isotherm maps shows that temperatures have increased by about 1°C in the city, as well as in the rural background areas over the last decades. This increase could be reproduced with trend analysis of temperature data gathered from several groundwater wells. Comparison between groundwater and air temperatures in Karlsruhe, for example, also indicates a spatial correlation between the urban heat island effect in the subsurface and in the atmosphere.

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

PubMed

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

2015-08-01

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

Anisotropic ion heating and BBELF waves within the low-altitude ion upflow region

NASA Astrophysics Data System (ADS)

Shen, Y.; Knudsen, D. J.; Burchill, J. K.; James, H. G.; Miles, D. M.

2016-12-01

Previous studies have shown that low-energy (<10 eV) ion upflow energization processes involve multiple steps. At the initial stage, contributions from transverse-to-B ion heating by wave-particle interaction (WPI) are often underestimated. The wave-generation mechanisms, the specific wave modes leading to the ion heating, and the minimum altitude where WPI takes place remain unresolved. With this in mind, we statistically investigate the relation between anisotropic ion temperature enhancements and broadband extremely low frequency (BBELF) wave emissions within the ion upflow region using data from the Suprathermal Electron imager (SEI), the Fluxgate Magnetometer (MGF), and the Radio Receiver Instrument (RRI) onboard the e-POP satellite. Initial results demonstrate that perpendicular-to-B ion temperatures can reach up to 4.3 eV in approximately 1 km wide spatial region near 410 km altitude inside an active auroral surge. Intense small-scale field-aligned currents (FACs) as well as strong BBELF wave emissions, comprising electromagnetic waves below 80 Hz and electrostatic waves above, accompany these ion heating events. The minimum altitude of potential WPI reported here is lower than as previously suggested as 520 km by Frederick-Frost et al. 2007. We measure polarization and power spectral density for specific wave modes to explore the nature of ion heating within the BBELF waves. Acknowledgement: This research is supported by an Eyes High Doctoral Recruitment Scholarship at University of Calgary.

ABLATIVE COMPOSITES FOR LIFTING REENTRY THERMAL PROTECTION.

DTIC Science & Technology

MECHANICAL PROPERTIES, THERMAL CONDUCTIVITY, ABLATION, DENSITY, TABLES(DATA), SPECIFIC HEAT, THERMOGRAVIMETRIC ANALYSIS, CORROSION RESISTANCE, COLORIMETRY , HEAT RESISTANT MATERIALS, ATMOSPHERE ENTRY.

Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

NASA Astrophysics Data System (ADS)

Freeburg, Eric Thomas

Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed outside the boundary layer. Vaporization of FC-72 droplets in the boundary layer next to the heated surface was not observed.

[Impact of daily mean temperature, cold spells, and heat waves on stroke mortality a multivariable Meta-analysis from 12 counties of Hubei province, China].

PubMed

Zhang, Y Q; Yu, C H; Bao, J Z

2017-04-10

Objective: To assess the acute effects of daily mean temperature, cold spells, and heat waves on stroke mortality in 12 counties across Hubei province, China. Methods: Data related to daily mortality from stroke and meteorology in 12 counties across Hubei province during 2009-2012, were gathered. Distributed lag nonlinear model (DLNM) was first used, to estimate the county-specific associations between daily mean temperature, cold spells, heat waves and stroke mortality. Multivariate Meta-analysis was then applied to pool the community-specific relationships between temperature and stroke mortality (exposure-response relationship) as well as both cold- and- heat-associated risks on mortality at different lag days (lag-response relationship). Results: During 2009-2012, a total population of 6.7 million was included in this study with 42 739 persons died of stroke. An average of 2.7 (from 0.5 to 6.0) stroke deaths occurred daily in each county, with annual average mean temperature as 16.6 ℃ (from 14.7 ℃ to 17.4 ℃) during the study period. An inverse J-shaped association between temperature and stroke mortality was observed at the provincial level. Pooled mortality effect of cold spells showed a 2-3-day delay and lasted about 10 days, while effect of heat waves appeared acute but attenuated within a few days. The mortality risks on cold-spell days ranged from 0.968 to 1.523 in 12 counties at lag 3-14, with pooled effect as 1.180 (95 %CI: 1.043-1.336). The pooled mortality risk (ranged from 0.675 to 2.066) on heat-wave days at lag 0-2 was 1.114 (95 %CI: 1.012-1.227). Conclusions: An inverse J-shaped association between temperature and stroke mortality was observed in Hubei province, China. Both cold spells and heat waves were associated with increased stroke mortality, while different lag patterns were observed in the mortality effects of heat waves and cold spells.

Process gas hear recovery

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

Anderson, W.M.; Thurner, R.P.

1977-01-01

In considering the use of regenerative and recuperative heat exchangers for process-gas heat recovery general information regarding heat-exchanger effectiveness versus initial capital investment and operating costs is discussed. Specific examples for preheating combustion air for process furnaces and for using primary and secondary heat exchangers in conjunction with an air-pollution-control system for drying and curing ovens cover basic heat-exchanger design and application considerations as well as investment-payback factors.

Single Crystal Synthesis and STM Studies of High Temperature Superconductors

NASA Technical Reports Server (NTRS)

Barrientos, Alfonso

1997-01-01

This is a final report for the work initiated in September of 1994 under the grant NAG8-1085 - NASA/OMU, on the fabrication of bulk and single crystal synthesis, specific heat measuring and STM studies of high temperature superconductors. Efforts were made to fabricate bulk and single crystals of mercury based superconducting material. A systematic thermal analysis on the precursors for the corresponding oxides and carbonates were carried out to synthesized bulk samples. Bulk material was used as seed in an attempt to grow single crystals by a two-step self flux process. On the other hand bulk samples were characterized by x-ray diffraction, electrical resistivity and magnetic susceptibility, We studied the specific heat behavior in the range from 80 to 300 K. Some preliminary attempts were made to study the atomic morphology of our samples. As part of our efforts we built an ac susceptibility apparatus for measuring the transition temperature of our sintered samples.

Experimental and Theoretical Studies of Axisymmetric Free Jets

NASA Technical Reports Server (NTRS)

Love, Eugene S.; Grigsby, Carl E.; Lee, Louise P.; Woodling, Mildred J.

1959-01-01

Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet boundary. Studies of the effects of the ratio of specific heats of the jets are included are observations pertaining to jet noise and jet simulation. For jets exhausting into supersonic streams, an attempt has been made to present primarily theoretical certain jet interference effects and in formulating experimental studies. The primary variables considered are jet Mach number, free stream Mach number, jet static pressure ratio, ratio of specific heats of the jet, nozzle exit angle, and boattail angle. The simulation problem and the case of a hypothetical hypersonic vehicle are examined, A few experimental observations are included.

An analysis of heat effects in different subpopulations of Bangladesh.

PubMed

Burkart, Katrin; Breitner, Susanne; Schneider, Alexandra; Khan, Md Mobarak Hossain; Krämer, Alexander; Endlicher, Wilfried

2014-03-01

A substantial number of epidemiological studies have demonstrated an association between atmospheric conditions and human all-cause as well as cause-specific mortality. However, most research has been performed in industrialised countries, whereas little is known about the atmosphere-mortality relationship in developing countries. Especially with regard to modifications from non-atmospheric conditions and intra-population differences, there is a substantial research deficit. Within the scope of this study, we aimed to investigate the effects of heat in a multi-stratified manner, distinguishing by the cause of death, age, gender, location and socio-economic status. We examined 22,840 death counts using semi-parametric Poisson regression models, adjusting for a multitude of potential confounders. Although Bangladesh is dominated by an increase of mortality with decreasing (equivalent) temperatures over a wide range of values, the findings demonstrated the existence of partly strong heat effects at the upper end of the temperature distribution. Moreover, the study demonstrated that the strength of these heat effects varied considerably over the investigated subgroups. The adverse effects of heat were particularly pronounced for males and the elderly above 65 years. Moreover, we found increased adverse effects of heat for urban areas and for areas with a high socio-economic status. The increase in, and acceleration of, urbanisation in Bangladesh, as well as the rapid aging of the population and the increase in non-communicable diseases, suggest that the relevance of heat-related mortality might increase further. Considering rising global temperatures, the adverse effects of heat might be further aggravated.

Roles of heat shock factors in gametogenesis and development.

PubMed

Abane, Ryma; Mezger, Valérie

2010-10-01

Heat shock factors form a family of transcription factors (four in mammals), which were named according to the first discovery of their activation by heat shock. As a result of the universality and robustness of their response to heat shock, the stress-dependent activation of heat shock factor became a ‘paradigm’: by binding to conserved DNA sequences (heat shock elements), heat shock factors trigger the expression of genes encoding heat shock proteins that function as molecular chaperones, contributing to establish a cytoprotective state to various proteotoxic stress and in several pathological conditions. Besides their roles in the stress response, heat shock factors perform crucial roles during gametogenesis and development in physiological conditions. First, during these process, in stress conditions, they are either proactive for survival or, conversely, for apoptotic process, allowing elimination or, inversely, protection of certain cell populations in a way that prevents the formation of damaged gametes and secure future reproductive success. Second, heat shock factors display subtle interplay in a tissue- and stage-specific manner, in regulating very specific sets of heat shock genes, but also many other genes encoding growth factors or involved in cytoskeletal dynamics. Third, they act not only by their classical transcription factor activities, but are necessary for the establishment of chromatin structure and, likely, genome stability. Finally, in contrast to the heat shock gene paradigm, heat shock elements bound by heat shock factors in developmental process turn out to be extremely dispersed in the genome, which is susceptible to lead to the future definition of ‘developmental heat shock element’.

49 CFR 179.200-11 - Postweld heat treatment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Postweld heat treatment. 179.200-11 Section 179... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-11 Postweld heat treatment. When specified in § 179.201-1, after welding is complete, postweld heat treatment must be in compliance...

Heat-Energy Analysis for Solar Receivers

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1982-01-01

Heat-energy analysis program (HEAP) solves general heat-transfer problems, with some specific features that are "custom made" for analyzing solar receivers. Can be utilized not only to predict receiver performance under varying solar flux, ambient temperature and local heat-transfer rates but also to detect locations of hotspots and metallurgical difficulties and to predict performance sensitivity of neighboring component parameters.

Determination of thermophysical characteristics of solid materials by electrical modelling of the solutions to the inverse problems in nonsteady heat conduction

NASA Technical Reports Server (NTRS)

Kozdoba, L. A.; Krivoshei, F. A.

1985-01-01

The solution of the inverse problem of nonsteady heat conduction is discussed, based on finding the coefficient of the heat conduction and the coefficient of specific volumetric heat capacity. These findings are included in the equation used for the electrical model of this phenomenon.

Procedure de caracterisation thermophysique d'un materiau a changement de phase composite pour le stockage thermique

NASA Astrophysics Data System (ADS)

Le Du, Mathieu

The use of phase change materials (PCMs) allows to store and release large amounts of energy in reduced volumes by using latent heat storage through melting and solidifying at specific temperatures. Phase change materials received a great interest for reducing energy consumption by easing the implementation of passive solar heating and cooling. They can be integrated to buildings as wallboards to improve the heat storage capacity. In this study, an original experimental device has allowed to characterize the thermophysical proprieties of a composite wallboard constituted of PCMs. Generally, PCMs are characterized by calorimetric methods which use very small quantities of material. The device used can characterize large sample's dimensions, as they could be used in real condition. Apparent thermal conductivity and specific heat have been measured for various temperatures. During phase change process, total and latent heat storage capacities have been evaluated with the peak melting and freezing temperatures. Results are compared to the manufacturer's data and data from literature. Incoherencies have been found between sources. Despite several differences with published data, overall results are similar to the latest information, which allow validate the original experimental device. Thermal disturbances due to hysteresis have been noticed and discussed. Results allow suggesting recommendations on thermal procedure and experimental device to characterize efficiently this kind of materials. Temperature's ranges and heating and freezing rates affect results and it must be considered in the characterization. Moreover, experimental devices have to be designed to allow similar heating and freezing rates in order to compare results during melting and freezing. Key words: Phase change material, latent thermal storage, thermophysical characterization.

Heat acclimation and exercise training interact when combined in an overriding and trade-off manner: physiologic-genomic linkage

PubMed Central

Kodesh, Einat; Nesher, Nir; Simaan, Assi; Hochner, Benny; Beeri, Ronen; Gilon, Dan; Stern, Michael D.; Gerstenblith, Gary

2011-01-01

Combined heat acclimation (AC) and exercise training (EX) enhance exercise performance in the heat while meeting thermoregulatory demands. We tested the hypothesis that different stress-specific adaptations evoked by each stressor individually trigger similar cardiac alterations, but when combined, overriding/trade-off interactions take place. We used echocardiography, isolated cardiomyocyte imaging and cDNA microarray techniques to assay in situ cardiac performance, excitation-contraction (EC) coupling features, and transcriptional programs associated with cardiac contractility. Rat groups studied were controls (sedentary 24°C); AC (sedentary, 34°C, 1 mo); normothermic EX (treadmill at 24°C, 1 mo); and heat-acclimated, exercise-trained (EXAC; treadmill at 34°C, 1 mo). Prolonged heat exposure decreased heart rate and contractile velocity and increased end ventricular diastolic diameter. Compared with controls, AC/EXAC cardiomyocytes demonstrated lower l-type Ca2+ current (ICaL) amplitude, higher Ca2+ transient (Ca2+T), and a greater Ca2+T-to-ICaL ratio; EX alone enhanced ICaL and Ca2+T, whereas aerobic training in general induced cardiac hypertrophy and action potential elongation in EX/EXAC animals. At the genomic level, the transcriptome profile indicated that the interaction between AC and EX yields an EXAC-specific molecular program. Genes affected by chronic heat were linked with the EC coupling cascade, whereas aerobic training upregulated genes involved with Ca2+ turnover via an adrenergic/metabolic-driven positive inotropic response. In the EXAC cardiac phenotype, the impact of chronic heat overrides that of EX on EC coupling components and heart rate, whereas EX regulates cardiac morphometry. We suggest that concerted adjustments induced by AC and EX lead to enhanced metabolic and mechanical performance of the EXAC heart. PMID:21957158

Superconducting properties and μSR study of the noncentrosymmetric superconductor Nb0.5Os0.5.

PubMed

Singh, D; Barker, J A T; Thamizhavel, A; Hillier, A D; Paul, D McK; Singh, R P

2018-01-22

The properties of the noncentrosymmetric superconductor (α-[Formula: see text] structure) Nb 0.5 Os 0.5 have been investigated using resistivity, magnetization, specific heat, and muon spin relaxation and rotation (μSR) measurements. These measurements suggest that Nb 0.5 Os 0.5 is a weakly coupled ([Formula: see text]) type-II superconductor ([Formula: see text]), having a bulk superconducting transition temperature T c   =  3.07 K. The specific heat data fits well with the single-gap BCS model indicating nodeless s-wave superconductivity in Nb 0.5 Os 0.5 . The μSR measurements also confirm [Formula: see text]-wave superconductivity with the preserved time-reversal symmetry.

Bleed cycle propellant pumping in a gas-core nuclear rocket engine system

NASA Technical Reports Server (NTRS)

Kascak, A. F.; Easley, A. J.

1972-01-01

The performance of ideal and real staged primary propellant pumps and bleed-powered turbines was calculated for gas-core nuclear rocket engines over a range of operating pressures from 500 to 5000 atm. This study showed that for a required engine operating pressure of 1000 atm the pump work was about 0.8 hp/(lb/sec), the specific impulse penalty resulting from the turbine propellant bleed flow as about 10 percent; and the heat required to preheat the propellant was about 7.8 MN/(lb/sec). For a specific impulse above 2400 sec, there is an excess of energy available in the moderator due to the gamma and neutron heating that occurs there. Possible alternative pumping cycles are the Rankine or Brayton cycles.

Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India.

PubMed

Krishnamurthy, Manikandan; Ramalingam, Paramesh; Perumal, Kumaravel; Kamalakannan, Latha Perumal; Chinnadurai, Jeremiah; Shanmugam, Rekha; Srinivasan, Krishnan; Venugopal, Vidhya

2017-03-01

Workers laboring in steel industries in tropical settings with high ambient temperatures are subjected to thermally stressful environments that can create well-known risks of heat-related illnesses and limit workers' productivity. A cross-sectional study undertaken in a steel industry in a city nicknamed "Steel City" in Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration from urine color and urine specific gravity. A structured questionnaire captured self-reported heat-related health symptoms of workers. Some 90% WBGT measurements were higher than recommended threshold limit values (27.2-41.7°C) for heavy and moderate workloads and radiational heat from processes were very high in blooming-mill/coke-oven (67.6°C globe temperature). Widespread heat-related health concerns were prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures (χ 2  = 26.1258, degrees of freedom = 1, p  < 0.001). Change in urine color was 7.4 times higher among workers exposed to WBGTs above threshold limit values (TLVs). Preliminary evidence shows that high heat exposures and heavy workload adversely affect the workers' health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

Laminar and turbulent heating predictions for mars entry vehicles

NASA Astrophysics Data System (ADS)

Wang, Xiaoyong; Yan, Chao; Zheng, Weilin; Zhong, Kang; Geng, Yunfei

2016-11-01

Laminar and turbulent heating rates play an important role in the design of Mars entry vehicles. Two distinct gas models, thermochemical non-equilibrium (real gas) model and perfect gas model with specified effective specific heat ratio, are utilized to investigate the aerothermodynamics of Mars entry vehicle named Mars Science Laboratory (MSL). Menter shear stress transport (SST) turbulent model with compressible correction is implemented to take account of the turbulent effect. The laminar and turbulent heating rates of the two gas models are compared and analyzed in detail. The laminar heating rates predicted by the two gas models are nearly the same at forebody of the vehicle, while the turbulent heating environments predicted by the real gas model are severer than the perfect gas model. The difference of specific heat ratio between the two gas models not only induces the flow structure's discrepancy but also increases the heating rates at afterbody of the vehicle obviously. Simple correlations for turbulent heating augmentation in terms of laminar momentum thickness Reynolds number, which can be employed as engineering level design and analysis tools, are also developed from numerical results. At the time of peak heat flux on the +3σ heat load trajectory, the maximum value of momentum thickness Reynolds number at the MSL's forebody is about 500, and the maximum value of turbulent augmentation factor (turbulent heating rates divided by laminar heating rates) is 5 for perfect gas model and 8 for real gas model.

Crystal structure and low-energy Einstein mode in ErV{sub 2}Al{sub 20} intermetallic cage compound

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

Winiarski, Michał J., E-mail: mwiniarski@mif.pg.gda.pl; Klimczuk, Tomasz

Single crystals of a new ternary aluminide ErV{sub 2}Al{sub 20} were grown using a self-flux method. The crystal structure was determined by powder X-ray diffraction measurements and Rietveld refinement, and physical properties were studied by means of electrical resistivity, magnetic susceptibility and specific heat measurements. These measurements reveal that ErV{sub 2}Al{sub 20} is a Curie-Weiss paramagnet down to 1.95 K with an effective magnetic moment μ{sub eff} =9.27(1) μ{sub B} and Curie-Weiss temperature Θ{sub CW} =−0.55(4) K. The heat capacity measurements show a broad anomaly at low temperatures that is attributed to the presence of a low-energy Einstein mode withmore » characteristic temperature Θ{sub E} =44 K, approximately twice as high as in the isostructural ‘Einstein solid’ VAl{sub 10.1}. - Graphical abstract: A low-energy Einstein mode is observed in a novel intermetallic cage compound ErV{sub 2}Al{sub 20} by specific heat and resistivity measurements. - Highlights: • Single crystals of a new compound ErV{sub 2}Al{sub 20} were grown by self-flux method. • Crystal structure is reported, based on powder x-ray diffraction. • ErV{sub 2}Al{sub 20} is a Curie-Weiss paramagnet. • Low-energy ‘rattling’ phonon mode (Θ{sub E}=44 K) is found in specific heat measurements.« less

COMPARISON OF A GENUS-SPECIFIC CONVENTIONAL PCR AND A SPECIES-SPECIFIC NESTED-PCR FOR MALARIA DIAGNOSIS USING FTA COLLECTED SAMPLES FROM KINGDOM OF SAUDI ARABIA.

PubMed

Al-Harthi, Saeed A

2015-12-01

Molecular tools are increasingly accepted as the most sensitive and reliable techniques for malaria diagnosis and epidemiological surveys. Also, collection of finger prick blood spots onto filter papers is the most simple and affordable method for samples preservation and posterior molecular analysis, especially in rural endemic regions where malaria remains a major health problem. Two malaria molecular diagnostic tests, a Plasmodium genus-specific conventional PCR and a Plasmodium species-specific Nested PCR, were evaluated using DNA templates prepared from Whatman-FTA cards' dry blood spots using both, Methanol-fixation/Heat-extraction and FTA commercial purification kit. A total of 121 blood samples were collected from six Saudi south-western endemic districts both, as thick and thin films for routine microscopic screening and onto FTA cards for molecular studies. Out of the 121 samples, 75 were P. falciparum positive by at least one technique. No other species of Plasmodium were detected. P. falciparum parasites were identified in 69/75 (92%) samples by microscopic screening in health care centers. P. genus-specific PCR was able to amplify P. falciparum DNA in 41/75 (55%) and 59/75 (79%) samples using Methanol-fixation/Heat-extraction and FTA purification kit, respectively. P. species-specific Nested PCR revealed 68/75 (91%) and 75/75 (100%) positive samples using DNA templates were isolated by Methanol-fixation/Heat- extraction and FTA purification methods, respectively. The species-specific Nested PCR applied to Whatman-FTA preserved and processed blood samples represents the best alternative to classical microscopy for malaria diagnosis, particularly in epidemiological screening.

Effects of critical fluctuations and dimensionality on the jump in specific heat at the superconducting transition temperature: Application to YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds.

PubMed

Keumo Tsiaze, R M; Wirngo, A V; Mkam Tchouobiap, S E; Fotue, A J; Baloïtcha, E; Hounkonnou, M N

2016-06-01

We report on a study of the superconducting order parameter thermodynamic fluctuations in YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds. A nonperturbative technique within the framework of the renormalized Gaussian approach is proposed. The essential features are reported (analytically and numerically) through Ginzburg-Landau (GL) model-based calculations which take into account both the dimension and the microscopic parameters of the system. By presenting a self-consistent approach improvement on the GL theory, a technique for obtaining corrections to the asymptotic critical behavior in terms of nonuniversal parameters is developed. Therefore, corrections to the specific heat and the critical transition temperature for one-, two-, and three-dimensional samples are found taking into account the fact that fluctuations occur at all length scales as the critical point of a system is approached. The GL model in the free-field approximation and the 3D-XY model are suitable for describing the weak and strong fluctuation regimes respectively. However, with a modified quadratic coefficient, the renormalized GL model is able to explain certain experimental observations including the specific heat of complicated systems, such as the cup-rate superconductors and the β-pyrochlore oxides. It is clearly shown that the enhancement, suppression, or rounding of the specific heat jump of high-T_{c} cup-rate superconductors at the transition are indicative of the order parameter thermodynamic fluctuations according to the dimension and the nature of interactions.