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Sample records for ambient high temperature

  1. Evaluating alternative refrigerants for high ambient temperature environments

    SciTech Connect

    Abdelaziz, Omar; Shrestha, Som S.

    2016-01-01

    According to the Montreal Protocol, developing countries have started the phase out schedule of the ozone depleting substances, including HCFC refrigerants, in 2015 and expect them to reach 35% reduction in 2020. This commitment to the start the phase out of HCFC refrigerants, especially R-22, in developing countries is seen as an opportunity to introduce lower Global Warming Potential (GWP) refrigerants. Furthermore, this paper summarizes an investigation into the performance of lower GWP refrigerants in high ambient temperature environments, experienced in some of the developed countries, in mini-split air conditioning units.

  2. Exposure to high ambient temperatures alters embryology in rabbits

    NASA Astrophysics Data System (ADS)

    García, M. L.; Argente, M. J.

    2017-03-01

    High ambient temperatures are a determining factor in the deterioration of embryo quality and survival in mammals. The aim of this study was to evaluate the effect of heat stress on embryo development, embryonic size and size of the embryonic coats in rabbits. A total of 310 embryos from 33 females in thermal comfort zone and 264 embryos of 28 females in heat stress conditions were used in the experiment. The traits studied were ovulation rate, percentage of total embryos, percentage of normal embryos, embryo area, zona pellucida thickness and mucin coat thickness. Traits were measured at 24 and 48 h post-coitum (hpc); mucin coat thickness was only measured at 48 hpc. The embryos were classified as zygotes or two-cell embryos at 24 hpc, and 16-cells or early morulae at 48 hpc. The ovulation rate was one oocyte lower in heat stress conditions than in thermal comfort. Percentage of normal embryos was lower in heat stress conditions at 24 hpc (17.2%) and 48 hpc (13.2%). No differences in percentage of zygotes or two-cell embryos were found at 24 hpc. The embryo development and area was affected by heat stress at 48 hpc (10% higher percentage of 16-cells and 883 μm2 smaller, respectively). Zona pellucida was thicker under thermal stress at 24 hpc (1.2 μm) and 48 hpc (1.5 μm). No differences in mucin coat thickness were found. In conclusion, heat stress appears to alter embryology in rabbits.

  3. Effects of High Ambient Temperature on Various Stages of Rabies Virus Infection in Mice

    PubMed Central

    Bell, J. F.; Moore, G. J.

    1974-01-01

    Effects of high ambient temperatures on various stages of rabies virus infection have been studied. Ambient temperature increased within the tolerated range was found to have little effect upon body temperature of normal mice, but caused marked elevation of temperature during illness. Temperatures at onset of patent illness in mice were lower than normal. Increased body temperature in the higher thermic ambience during the incubation period was associated with decreased mortality and frequent abortive infections. Exposure to high ambient temperature late in the incubation period delayed onset of illness, decreased mortality, and increased frequency of abortive infections, but exposure to high ambient temperature after onset of patent illness did not affect the course of the disease. PMID:4426698

  4. The Genetic Control of Reproductive Development under High Ambient Temperature1[OPEN

    PubMed Central

    2017-01-01

    Ambient temperature has a large impact on reproductive development and grain yield in temperate cereals. However, little is known about the genetic control of development under different ambient temperatures. Here, we demonstrate that in barley (Hordeum vulgare), high ambient temperatures accelerate or delay reproductive development depending on the photoperiod response gene PHOTOPERIOD1 (Ppd-H1) and its upstream regulator EARLY FLOWERING3 (HvELF3). A natural mutation in Ppd-H1 prevalent in spring barley delayed floral development and reduced the number of florets and seeds per spike, while the wild-type Ppd-H1 or a mutant Hvelf3 allele accelerated floral development and maintained the seed number under high ambient temperatures. High ambient temperature delayed the expression phase and reduced the amplitude of clock genes and repressed the floral integrator gene FLOWERING LOCUS T1 independently of the genotype. Ppd-H1-dependent variation in flowering time under different ambient temperatures correlated with relative expression levels of the BARLEY MADS-box genes VERNALIZATION1 (HvVRN1), HvBM3, and HvBM8 in the leaf. Finally, we show that Ppd-H1 interacts with regulatory variation at HvVRN1. Ppd-H1 only accelerated floral development in the background of a spring HvVRN1 allele with a deletion in the regulatory intron. The full-length winter Hvvrn1 allele was strongly down-regulated, and flowering was delayed by high temperatures irrespective of Ppd-H1. Our findings demonstrate that the photoperiodic and vernalization pathways interact to control flowering time and floret fertility in response to ambient temperature in barley. PMID:28049855

  5. Rise in lens temperature on exposure to sunlight or high ambient temperature.

    PubMed Central

    Al-Ghadyan, A. A.; Cotlier, E.

    1986-01-01

    The effect of increase ambient temperature and sunlight on the temperatures of the rabbit lens and posterior chamber (PC) aqueous humour was measured by needle thermistor probes while the rectal temperature was monitored. Exposure of rabbits to sunlight (35 degrees-42 degrees C), in New Haven, Connecticut, USA, resulted in significant temperature increases in PC (4.3 degrees C), lens (3.2 degrees C), and rectum (2.3 degrees C). Returning animals to the shade resulted in a progressive decrease in the temperatures of the PC or lens in the tested eye, but repeating exposure to sunlight resulted in significant increases of the baseline (PC) temperature (increase 2.68 degrees C) of the second eye. Exposure of rabbits to sunlight at 49 degrees C in Chandigarh, India, resulted in increased PC temperature of 4.48 degrees C after 9 minutes. Increased PC and lens temperatures after exposure to sunlight are due both to an ambient temperature effect through the cornea and to increased body temperature. In dry and hot tropical areas of the world temperature increases in the lens after exposure to sunlight may initiate or accelerate the formation of senile cataracts. PMID:3718905

  6. STRATEGIES TO IMPROVE ADAPTATION OF COMMON BEAN TO HIGH AMBIENT TEMPERATURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High ambient temperatures are a significant constraint to low-land tropical and an intermittent constraint to temperate common bean production, while climate change promises a continued warming trend. To offset the effects of this trend, efforts are been made to understand the genetics and the physi...

  7. MOVPE growth of laser structures for high-power applications at different ambient temperatures

    NASA Astrophysics Data System (ADS)

    Bugge, F.; Crump, P.; Frevert, C.; Knigge, S.; Wenzel, H.; Erbert, G.; Weyers, M.

    2016-10-01

    Laser structures for different operating temperatures were developed. Higher temperatures need an increase in barrier height to reduce carrier leakage. Best results for an emission wavelength of ≈800 nm were obtained using an asymmetric structure containing an n-InGaP and a p-Al0.5Ga0.5As waveguide. Such structures show 10 W output power for a single laser diode and >100 W for a laser bar at 50 °C ambient temperature and also a good aging behavior. Lower operating temperatures permit lower barrier heights which results in a lower series resistance and therefore higher conversion efficiency at high power. Carrier concentration and mobility for different AlxGa1-xAs compositions were estimated in dependence on temperature. An optimized structure reached 20 W for a single laser diode and 2 kW for a laser bar in QCW mode at -70 °C.

  8. Effect of high ambient temperature on behavior of sheep under semi-arid tropical environment

    NASA Astrophysics Data System (ADS)

    De, Kalyan; Kumar, Davendra; Saxena, Vijay Kumar; Thirumurugan, Palanisamy; Naqvi, Syed Mohammed Khursheed

    2017-01-01

    High environmental temperature is a major constraint in sheep production under semi-arid tropical environment. Behavior is the earliest indicator of animal's adaptation and responses to the environmental alteration. Therefore, the objective of this study was to assess the effects of high ambient temperature on the behavior of sheep under a semi-arid tropical environment. The experiment was conducted for 6 weeks on 16 Malpura cross (Garole × Malpura × Malpura (GMM)) rams. The rams were divided equally into two groups, designated as C and T. The rams of C were kept in comfortable environmental conditions served as control. The rams of T were exposed to a different temperature at different hours of the day in a climatic chamber, to simulate a high environmental temperature of summer in semi-arid tropic. The behavioral observations were taken by direct instantaneous observation at 15-min intervals for each animal individually. The feeding, ruminating, standing, and lying behaviors were recorded twice a week from morning (0800 hours) to afternoon (1700 hours) for 6 weeks. Exposure of rams to high temperature (T) significantly (P < 0.05) decreased the proportion of time spent in feeding during the observation period in most of the hours of the day as compared to the C. The proportion of time spent in rumination and lying was significantly (P < 0.05) lower in the T group compared to the C. The animals of T spent significantly (P < 0.05) more time in rumination in standing position as compared to the C. The overall proportion of time spent in standing, panting in each hour, and total panting time was significantly (P < 0.05) higher in the T as compared to the C. The result of the study indicates that the exposure of sheep to high ambient temperature severely modulates the behavior of sheep which is directed to circumvent the effect of the stressor.

  9. Effects of high ambient temperatures on the metabolism of West African dwarf goats. II

    NASA Astrophysics Data System (ADS)

    Montsma, G.; Luiting, P.; Verstegen, M. W. A.; van der Hel, W.; Hofs, P.; Zijlker, J. W.

    1985-03-01

    32 West African dwarf goats were exposed in respiration chambers to temperature treatments of 20, 25, 30, 35, 35, 35, 30, 25, 20°C. Each treatment lasted three days. 16 goats were kept in individual pens (“I”); the others in two group pens of eight animals each (“G”). During each treatment, heat production and activity were recorded continuously over 48 hours. In addition, feed and water intake, rectal temperature, skin temperature and respiratory rate were measured during each treatment. Compared to 20°C, at 35°C rectal temperature increased from 39.0°C to 39.9°C, respiratory rate from 30 to 260 times. min-1 and skin temperature from 37.1°C to 39.5°C. Hay intake decreased by 40%; concentrates (30 g. kg-0.75. d-1) were always completely consumed. Heat production was higher for the “G” animals at 20°C and higher for the “I” animals at 35°C. These differences in heat production between the two groups were reflected in differences in rectal and skin temperature and in respiratory rate but only very slightly in differences in hay intake. Tissue insulation was 0.014 K. m2. W-1 at 30°C and 35°C and 0.022 K. m2. W-1 at 20°C. It is concluded that the reactions of these dwarf goats to high ambient temperatures are not different in principle from those of other domestic ruminants and that they do not exhibit a specific suitability or unsuitability for ambient temperatures as prevailing in West Africa.

  10. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Rooftop Air Conditioners

    SciTech Connect

    Abdelaziz, Omar; Shrestha, Som S.; Shen, Bo; Linkous, Randall Lee; Goetzler, William; Guernsey, Matt; Bargach, Youssef

    2016-09-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for Low-Global Warming Potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants relative to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in packaged or Rooftop Unit (RTU) air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerants selection process, the test procedures, and the final results.

  11. Ventilation plays an important role in hens' egg production at high ambient temperature.

    PubMed

    Ruzal, M; Shinder, D; Malka, I; Yahav, S

    2011-04-01

    Birds dissipate considerable heat through respiratory-evaporative and cutaneous-evaporative mechanisms and sensible heat loss (SHL) via radiation, convection, and conduction. The significance of SHL in laying hens is still to be confirmed. This study aimed to elucidate the effect of ventilation on egg production and quality during exposure to high ambient temperature. Lohman laying hens were raised outdoors up to age 35 wk, and 300 hens with similar egg production were divided among 5 treatments each comprising 4 replicates of 15 hens. Birds in 4 treatments were kept in computerized controlled-environment rooms acclimated to 35°C and 50% RH, with ventilation flow rates of 0.5, 1.5, 2.0, and 3.0 m/s, respectively, and those in the control were kept outdoors. Hens were acclimated to the controlled environment rooms for 1 wk and to the targeted environmental conditions for another week, and then were subjected to measurements for 2 wk. Egg production, mass, and shell density, and feed and water consumption were monitored. Body temperature, SHL, and plasma thyroid hormone concentrations were measured at the end of the experiment. The high environmental temperature impaired egg production and quality: whereas exposure of hens to ventilation flows of 2.0 and 3.0 m/s elicited significant recovery of these parameters with time, exposure to a rate of 0.5 m/s negatively affected these parameters throughout the experimental period. The highest feed intake and water consumption were observed in hens exposed to 2.0 and 3.0 m/s, respectively, and the highest SHL was observed in those exposed to 3.0 m/s. It can be concluded that ventilation rate significantly affected hens exposed to high ambient temperature: high ventilation (3.0 m/s) improved egg production whereas low ventilation (0.5 m/s) negatively affected production and quality.

  12. Effects of zinc sulfate pretreatment on heat tolerance of Bama miniature pig under high ambient temperature.

    PubMed

    Li, Y; Cao, Y; Zhou, X; Wang, F; Shan, T; Li, Z; Xu, W; Li, C

    2015-07-01

    The aim of this study was to evaluate the heat tolerance of Bama miniature pigs under high ambient temperature (40°C) and Zn interactive functions during heat treatment (HT). Bama miniature pigs (male; n = 24; 6-mo old; BW = 10.79 ± 0.06 kg) were randomly allotted to 4 groups and were fed a basal diet or the basal diet supplemented with 1,500 mg of Zn (ZnSO4·H2O)/kg diet for 38 d. At 7 mo of age (d 30), the thermal neutral (TN) groups remained at 25°C, whereas the HT groups were exposed to ambient temperature at 40°C for 5 h daily for 8 consecutive days. Pigs in 4 groups were sacrificed on d 38. Individual rectal temperatures, skin temperatures, and breathing rates were recorded at 3 h after the onset of HT and the blood samples were collected immediately after HT on d 30, 34, and 38. Pigs fed diets with or without Zn doubled their breathing rates (P < 0.05) and increased body surface, scrotal, and rectal temperatures during HT on d 30, 34, and 38, respectively. Zinc supplementation increased BW gain (BWG; P < 0.05) during 38-d experiment period, and HT decreased BWG only from d 30 to 34 (P < 0.05). Heat treatment increased serum testosterone on d 30 (P < 0.05). Zinc supplementation decreased the heat-induced increase of testosterone in HT on d 30 and 34 (P < 0.05). The relative weight of liver increased in HT groups (P < 0.05). Zinc supplementation decreased the relative weights of spleen (P < 0.05) and testis (P < 0.01). The values of abnormal lymphocyte count and large unstained cell count declined approximately 5 times in groups of Zn supplementation, whereas Zn supplementation increased the values of red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin. Zinc concentrations increased in serum, liver, kidney, epididymis, longissimus, hair, and feces in groups fed with Zn (P < 0.01). However, additional Zn decreased Zn concentrations in lung, spleen, and testis (P < 0.01). Moreover, HT decreased serum Zn

  13. Study on the High Cycle Fatigue Property of Ti-600 Alloy at Ambient Temperature

    NASA Astrophysics Data System (ADS)

    Zeng, Liying; Yang, Guanjun; Hong, Quan; Zhao, Yongqing

    2011-06-01

    High cycle fatigue (HCF) property of one kind of near alpha titanium alloy named after Ti-600 was investigated at a frequency of 120~130Hz and with a load ratio R of 0.1. The HCF strength for the alloy at ambient temperature was found to be 475MPa. The observed high HCF strength was attributed to its overlapping plate like α+β phase microstructure. At the same stress of 600MPa, the distance between two fatigue stripes for the sample fractured at 8.61×105 cycles was wider than that of the sample failured at 1.78×106 cycles, which indicated that their propagation resistance for fatigue cracks was smaller.

  14. 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

  15. Light-induced catalyst and solvent-free high pressure synthesis of high density polyethylene at ambient temperature.

    PubMed

    Ceppatelli, Matteo; Bini, Roberto

    2014-04-01

    The combined effect of high pressure and electronic photo-excitation has been proven to be very efficient in activating extremely selective polymerisations of small unsaturated hydrocarbons in diamond anvil cells (DAC). Here we report an ambient temperature, large volume synthesis of high density polyethylene based only on high pressure (0.4-0.5 GPa) and photo-excitation (~350 nm), without any solvent, catalyst or radical initiator. The reaction conditions are accessible to the current industrial technology and the laboratory scale pilot reactor can be scaled up to much larger dimensions for practical applications. FTIR and Raman spectroscopy, and X-ray diffraction, indicate that the synthesised material is of comparable quality with respect to the outstanding crystalline material obtained in the DAC. The polydispersity index is comparable to that of IV generation Ziegler-Natta catalysts. Moreover the crystalline quality of the synthesised material can be further enhanced by a thermal annealing at 373 K and ambient pressure.

  16. Tricalcium silicate (C{sub 3}S) hydration under high pressure at ambient and high temperature (200 deg. C)

    SciTech Connect

    Meducin, F.; Zanni, H.; Noik, C.; Hamel, G.; Bresson, B.

    2008-03-15

    The hydration of a tricalcium silicate paste at ambient temperature and at 200 deg. C under high pressure (up to 1000 bar) has been studied. Two high pressure cells have been used, one allows in-situ electrical conductivity measurements during hydration under high pressure. The hydration products were characterized by thermal analysis, X-ray diffraction and {sup 29}Si NMR measurements. The pressure has a large kinetic effect on the hydration of a C{sub 3}S paste at room temperature. The pressure was seen to affect drastically the hydration of a C{sub 3}S paste at 200 deg. C and this study evidences the competition between the different high temperature phases during the hydration.

  17. Effects of shade on welfare and meat quality of grazing sheep under high ambient temperature.

    PubMed

    Liu, H W; Cao, Y; Zhou, D W

    2012-12-01

    This study was conducted to evaluate the effects of providing shade on growth performance, welfare, and meat quality of grazing sheep under high ambient temperature. A total of 120 healthy male Ujumqin wool sheep (a local breed; BW = 18.7 ± 1.27 kg; 14 wk old) were randomly and equally divided into shaded and unshaded treatments with 3 pens per treatment. Sheep were grazed on an unshaded pastureland from 0600 to 1000 h and 1400 to 1800 h. During other times, sheep were confined in shaded or unshaded pens. Body weight was recorded on d 1 and 42 of the experiment. Rectal temperature and respiration rate were recorded on d 7, 14, 21, 28, 35, and 42. At end of the trial, sheep were blood sampled and slaughtered to collect meat samples. Respiration rate was greater (P < 0.05) in the unshaded sheep than shaded sheep on d 14, 21, 28, 35, and 42 of the trial whereas no significant differences were found on d 7. Moreover, no differences were observed in final BW, ADG, or rectal temperature throughout the trial. The pH at 24 h postmortem (pH(24)) and cooking loss were greater (P < 0.01) in unshaded than shaded sheep. On the contrary, lightness (L*), redness (a*) and yellowness (b*) values at 24 h postmortem were lower (P < 0.05) in unshaded versus shaded sheep. The sheep in the unshaded group had a greater (P < 0.05) cortisol concentration compared with the shaded group. Sheep in the shaded group had lower creatine kinase activity (P < 0.01) as well as observed for glucose (P < 0.05), triiodothyronine (P < 0.01), and thyroxine (P < 0.05) concentrations and white blood cell count (P < 0.05). Compared with the unshaded group, sheep in the shaded group had a greater lymphocytes (LYM) count (P < 0.05). In contrast, the opposite was true for neutrophils (NEU) count (P < 0.01) and NEU:LYM ratio (P < 0.01). In conclusion, the shade cloth, although not enhancing ADG, improved meat quality traits and certain stress parameters in grazing sheep reared under high ambient temperature.

  18. The effect of high ambient temperature and hypercapnia on postprandial intestinal hyperemia in domestic cockerels.

    PubMed

    Bottje, W G; Harrison, P C

    1986-08-01

    Hubbard cockerels (2.8 to 3.6 kg) with chronically implanted electromagnetic blood flow probes placed on the celiac artery were used to determine the effect of elevated ambient temperature on postprandial intestinal hyperemia. Celiac mean blood flow (MBF) increased (P less than .05) from approximately 25 to 50 ml/min in response to feeding. When a thermoneutral temperature of 25 C was maintained, celiac MBF remained above 40 ml/min up to 210 min but fell below 25 ml/min by 300 min postprandial. In response to an acute heat exposure of 37 C, postprandial celiac MBF was reduced by approximately 50% in comparison to thermoneutral control values. Changes in celiac MBF during heat exposure were significantly (P less than .05) correlated (.60) with blood CO2 partial pressure (PCO2). To determine if flood PCO2 affected postprandial celiac MBF, cockerels were subjected to successive elevated ambient temperature and ambient CO2 treatments. Although cockerels exposed to 2.8% CO2 exhibited an increase in blood PCO2 regardless of temperature treatment, postprandial celiac MBF changes in these ambient CO2 experiments were only moderately correlated (P less than .05) with blood PCO2 (.34) but inversely correlated (-.83) with celiac vascular resistance (P less than .001). This study indicates that acute heat exposure reduces postprandial intestinal hyperemia and that this hemodynamic alteration was coincident with, but not necessarily dependent upon, changes in blood PCO2.

  19. The effect of glycerol hyperhydration on olympic distance triathlon performance in high ambient temperatures.

    PubMed

    Coutts, Aaron; Reaburn, Peter; Mummery, Kerry; Holmes, Mark

    2002-03-01

    The purpose of this study was to examine the effect of prior glycerol loading on competitive Olympic distance triathlon performance (ODT) in high ambient temperatures. Ten (3 female and 7 male) well-trained triathletes (VO2max = 58.4 +/- 2.4ml kg(-1) min(-1); bestODTtime = 131.5 +/- 2.6 min) completed 2 ODTs (1.5-km swim, 40-km bicycle, 10-km run) in a randomly assigned (placebo/ glycerol) double-blind study conducted 2 weeks apart. The wet-bulb globe temperature (outdoors) was 30.5 +/- 0.5 degrees C (relative humidity: 46.3 +/- 1.1%; hot) and 25.4 +/- 0.2 degrees C (relative humidity: 51.7 +/- 2.4%; warm) for day 1 and day 2, respectively. The glycerol solution consisted of 1.2 g of glycerol per kilogram of body mass (BM) and 25 ml of a 0.75 g x kg(-1) BM carbohydrate solution (Gatorade) and was consumed over a 60-min period, 2 hours prior to each ODT. Measures of performance (ODT time), fluid retention, urine output, blood plasma volume changes, and sweat loss were obtained prior to and during the ODT in both the glycerol and placebo conditions. Following glycerol loading, the increase in ODT completion time between the hot and warm conditions was significantly less than the placebo group (placebo 11:40 min vs. glycerol 1:47 min; p < .05). The majority of the performance improvement occurred during the final 10-km run leg of ODT on the hot day. Hyperhydration occurred as a consequence of a reduced diuresis (p < .05) and a subsequent increase in fluid retention (p < .05). No significant differences were observed in sweat loss between the glycerol and placebo conditions. Plasma volume expansion during the loading period was significantly greater (p < .05) on the hot day when glycerol appeared to attenuate the performance decrement in the heat. The present results suggest that glycerol hyperhydration prior to ODT in high ambient temperatures may provide some protection against the negative performance effects of competing in the heat.

  20. Performance comparison of laying hens segregating for the frizzle gene under thermoneutral and high ambient temperatures.

    PubMed

    Zerjal, T; Gourichon, D; Rivet, B; Bordas, A

    2013-06-01

    The effect on thermotolerance of the incompletely dominant frizzle (F) gene, which causes feather curling and feather mass reduction, was investigated in 281 laying hens that were homozygous for the frizzle mutation (FF), heterozygous (FN), or normally feathered (NN). One-half of the birds were kept under standard conditions (22°C) and half were exposed to high ambient temperatures (32°C) between 24 and 46 wk of age. Egg production, egg quality, feed efficiency, and dissection traits were recorded and compared. At standard conditions, egg production and quality traits did not differ among the 3 genotypes, whereas feed efficiency was lower for the homozygous birds. Under heat stress conditions, the superiority of the FF hens was evident for all egg quantity and quality traits. No significant difference was measured between heterozygous carriers and normally feathered hens, indicating that the incomplete dominant frizzle mutation behaved as a recessive mutation regarding heat tolerance. From this study, we deduced that the F mutation in its homozygous state has a beneficial effect in decreasing heat stress in poultry production, and it could be particularly advantageous in tropical countries where average temperatures are never too low to negatively affect feed efficiency.

  1. Growth and antioxidant status of broilers fed supplemental lysine and pyridoxine under high ambient temperature

    PubMed Central

    Khakpour Irani, Farzaneh; Daneshyar, Mohsen; Najafi, Ramin

    2015-01-01

    Three levels of lysine (90, 100 and 110% of Ross requirement) and of pyridoxine (3, 6 and 9 mg kg-1) were used in a 3 × 3 factorial experiment to investigate the growth and blood antioxidant ability of broilers under high ambient temperature. None of the dietary supplements affected the weight gain during the starter and grower periods. Although no significant differences were detected between the treatments during the entire period, high lysine level fed birds had a lower weight gain. At any levels of pyridoxine, high lysine fed birds were lighter than others. Neither the lysine nor pyridoxine changed the feed intake or feed conversion ratio during the starter, grower and entire period. However there was no significant difference between the treatments for blood malondialdehyde (MDA) concentration, medium lysine fed birds had lower blood MDA than other ones. No significant effects on blood triglyceride, total protein and blood superoxide dismutase activity were indicated with addition of any lysine or pyridoxine level. Medium lysine fed birds had decreased blood glutathione peroxidase activity compared to the birds of other treatments. It was concluded that providing the proposed dietary lysine requirement of Ross strain during heat stress ensuring the best body weight gain and body antioxidant ability. Higher lysine level causes the retarded weight gain due to higher excretion of arginine from the body and consequently higher lipid peroxidation. PMID:26261713

  2. Impact of high ambient temperature on unintentional injuries in high-income countries: a narrative systematic literature review

    PubMed Central

    Otte im Kampe, Eveline; Kovats, Sari; Hajat, Shakoor

    2016-01-01

    Objectives Given the likelihood of increased hot weather due to climate change, it is crucial to have prevention measures in place to reduce the health burden of high temperatures and heat waves. The aim of this review is to summarise and evaluate the evidence on the effects of summertime weather on unintentional injuries in high-income countries. Design 3 databases (Global Public Health, EMBASE and MEDLINE) were searched by using related keywords and their truncations in the title and abstract, and reference lists of key studies were scanned. Studies reporting heatstroke and intentional injuries were excluded. Results 13 studies met our inclusion criteria. 11 out of 13 studies showed that the risk of unintentional injuries increases with increasing ambient temperatures. On days with moderate temperatures, the increased risk varied between 0.4% and 5.3% for each 1°C increase in ambient temperature. On extreme temperature days, the risk of injuries decreased. 2 out of 3 studies on occupational accidents found an increase in work-related accidents during high temperatures. For trauma hospital admissions, 6 studies reported an increase during hot weather, whereas 1 study found no association. The evidence for impacts on injuries by subgroups such as children, the elderly and drug users was limited and inconsistent. Conclusions The present review describes a broader range of types of unintentional fatal and non-fatal injuries (occupational, trauma hospital admissions, traffic, fire entrapments, poisoning and drug overdose) than has previously been reported. Our review confirms that hot weather can increase the risk of unintentional injuries and accidents in high-income countries. The results are useful for injury prevention strategies. PMID:26868947

  3. Arsenic ambient conditions preventing surface degradation of GaAs during capless annealing at high temperatures

    NASA Technical Reports Server (NTRS)

    Kang, C. H.; Kondo, K.; Lagowski, J.; Gatos, H. C.

    1987-01-01

    Changes in surface morphology and composition caused by capless annealing of GaAs were studied as a function of annealing temperature, T(GaAs), and the ambient arsenic pressure controlled by the temperature, T(As), of an arsenic source in the annealing ampul. It was established that any degradation of the GaAs surface morphology could be completely prevented, providing that T(As) was more than about 0.315T(GaAs) + 227 C. This empirical relationship is valid up to the melting point temperature of GaAs (1238 C), and it may be useful in some device-processing steps.

  4. Lack of response of laying hens to relative humidity at high ambient temperature.

    PubMed

    Yahav, S; Shinder, D; Razpakovski, V; Rusal, M; Bar, A

    2000-12-01

    1. The effects of relative humidity (rh=40% to 70%) at high ambient temperature (Ta) on the performance of laying hens at different ages (8 to 10 months, Trial 1; and 16 to 18 months, Trial 2) was evaluated. Laying hens were exposed to 25 degrees C (control) for 3 weeks and thereafter acclimated for 1 week to 35 degrees C and 4 different rh. 2. Body weight declined significantly in young and older hens exposed to 60% or 70% and 70% rh, respectively: Food intake declined with increasing Ta, except in the case of older hens exposed to 60% rh, for which it remained relatively constant. Water consumption, however, increased with increasing Ta but the increase was significant in young hens exposed to 70% rh only. 3. Egg production was not affected by the changes in Ta. However, a decrease in egg production was observed in older hens exposed to 60% rh. 4. Egg weight (EW), shell weight (SW) and shell thickness (ST) were significantly reduced by exposure to elevated Ta, whereas % breakage significantly increased. In young hens, a response to rh was exhibited in ST which was significantly higher in hens exposed to the low rh (40% to 45%) than in those exposed to the highest rh (70% to 75%). 5. It can be concluded that Ta is the main environmental factor affecting young and older laying hens while the effect of rh is minor.

  5. Male weasels decrease activity and energy expenditure in response to high ambient temperatures.

    PubMed

    Zub, Karol; Fletcher, Quinn E; Szafrańska, Paulina A; Konarzewski, Marek

    2013-01-01

    The heat dissipation limit (HDL) hypothesis suggests that the capacity of endotherms to dissipate body heat may impose constraints on their energy expenditure. Specifically, this hypothesis predicts that endotherms should avoid the detrimental consequences of hyperthermia by lowering their energy expenditure and reducing their activity in response to high ambient temperatures (T(a)). We used an extensive data set on the daily energy expenditure (DEE, n = 27) and the daily activity time (AT, n = 48) of male weasels (Mustela nivalis) during the spring and summer breeding season to test these predictions. We found that T(a) was related in a "hump-shaped" (i.e. convex) manner to AT, DEE, resting metabolic rate (RMR) and metabolic scope (the ratio of DEE to RMR). These results support the HDL hypothesis because in response to warm Tas male weasels reduced their AT, DEE, and RMR. Although the activity and energy expenditure of large endotherms are most likely to be constrained in response to warm Tas because they are less able to dissipate heat, our results suggest that small endotherms may also experience constraints consistent with the HDL hypothesis.

  6. High ambient temperature increases 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy")-induced Fos expression in a region-specific manner.

    PubMed

    Hargreaves, G A; Hunt, G E; Cornish, J L; McGregor, I S

    2007-03-16

    3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a popular drug that is often taken under hot conditions at dance clubs. High ambient temperature increases MDMA-induced hyperthermia and recent studies suggest that high temperatures may also enhance the rewarding and prosocial effects of MDMA in rats. The present study investigated whether ambient temperature influences MDMA-induced expression of Fos, a marker of neural activation. Male Wistar rats received either MDMA (10 mg/kg i.p.) or saline, and were placed in test chambers for 2 h at either 19 or 30 degrees C. MDMA caused significant hyperthermia at 30 degrees C and a modest hypothermia at 19 degrees C. The 30 degrees C ambient temperature had little effect on Fos expression in vehicle-treated rats. However MDMA-induced Fos expression was augmented in 15 of 30 brain regions at the high temperature. These regions included (1) sites associated with thermoregulation such as the median preoptic nucleus, dorsomedial hypothalamus and raphe pallidus, (2) the supraoptic nucleus, a region important for osmoregulation and a key mediator of oxytocin and vasopressin release, (3) the medial and central nuclei of the amygdala, important in the regulation of social and emotional behaviors, and (4) the shell of the nucleus accumbens and (anterior) ventral tegmental area, regions associated with the reinforcing effects of MDMA. MDMA-induced Fos expression was unaffected by ambient temperature at many other sites, and was diminished at high temperature at one site (the islands of Calleja), suggesting that the effect of temperature on MDMA-induced Fos expression was not a general pharmacokinetic effect. Overall, these results indicate that high temperatures accentuate key neural effects of MDMA and this may help explain the widespread use of the drug under hot conditions at dance parties as well as the more hazardous nature of MDMA taken under such conditions.

  7. Effects of reproductive status and high ambient temperatures on the body temperature of a free-ranging basoendotherm.

    PubMed

    Levesque, Danielle L; Lobban, Kerileigh D; Lovegrove, Barry G

    2014-12-01

    Tenrecs (Order Afrosoricida) exhibit some of the lowest body temperatures (T b) of any eutherian mammal. They also have a high level of variability in both active and resting T bs and, at least in cool temperatures in captivity, frequently employ both short- and long-term torpor. The use of heterothermy by captive animals is, however, generally reduced during gestation and lactation. We present data long-term T b recordings collected from free-ranging S. setosus over the course of two reproductive seasons. In general, reproductive females had slightly higher (~32 °C) and less variable T b, whereas non-reproductive females and males showed both a higher propensity for torpor as well as lower (~30.5 °C) and more variable rest-phase T bs. Torpor expression defined using traditional means (using a threshold or cut-off T b) was much lower than predicted based on the high degree of heterothermy in captive tenrecs. However, torpor defined in this manner is likely to be underestimated in habitats where ambient temperature is close to T b. Our results caution against inferring metabolic states from T b alone and lend support to the recent call to define torpor in free-ranging animals based on mechanistic and not descriptive variables. In addition, lower variability in T b observed during gestation and lactation confirms that homeothermy is essential for reproduction in this species and probably for basoendothermic mammals in general. The relatively low costs of maintaining homeothermy in a sub-tropical environment might help shed light on how homeothermy could have evolved incrementally from an ancestral heterothermic condition.

  8. High ambient temperature reverses hypothalamic MC4 receptor overexpression in an animal model of anorexia nervosa.

    PubMed

    Gutiérrez, E; Churruca, I; Zárate, J; Carrera, O; Portillo, M P; Cerrato, M; Vázquez, R; Echevarría, E

    2009-04-01

    The potential involvement of the melanocortin system in the beneficial effects of heat application in rats submitted to activity-based anorexia (ABA), an analogous model of anorexia nervosa (AN), was studied. Once ABA rats had lost 20% of body weight, half of the animals were exposed to a high ambient temperature (HAT) of 32 degrees C, whereas the rest were maintained at 21 degrees C. Control sedentary rats yoked to ABA animals received the same treatment. ABA rats (21 degrees C) showed increased Melanocortin 4 (MC4) receptor and Agouti gene Related Peptide (AgRP) expression, and decreased pro-opiomelanocortin (POMC) mRNA levels (Real Time PCR), with respect to controls. Heat application increased weight gain and food intake, and reduced running rate in ABA rats, when compared with ABA rats at 21 degrees C. However, no changes in body weight and food intake were observed in sedentary rats exposed to heat. Moreover, heat application reduced MC4 receptor, AgRP and POMC expression in ABA rats, but no changes were observed in control rats. These results indicate that hypothalamic MC4 receptor overexpression could occur on the basis of the characteristic hyperactivity, weight loss, and self-starvation of ABA rats, and suggest the involvement of hypothalamic melanocortin neural circuits in behavioural changes shown by AN patients. Changes in AgRP and POMC expression could represent an adaptative response to equilibrate energy balance. Moreover, the fact that HAT reversed hypothalamic MC4 receptor overexpression in ABA rats indicates the involvement of brain melanocortin system in the reported beneficial effects of heat application in AN. A combination of MC4 receptor antagonists and heat application could improve the clinical management of AN.

  9. High atmospheric temperatures and ‘ambient incubation’ drive embryonic development and lead to earlier hatching in a passerine bird

    PubMed Central

    Griffith, Simon C.; Mainwaring, Mark C.; Sorato, Enrico; Beckmann, Christa

    2016-01-01

    Tropical and subtropical species typically experience relatively high atmospheric temperatures during reproduction, and are subject to climate-related challenges that are largely unexplored, relative to more extensive work conducted in temperate regions. We studied the effects of high atmospheric and nest temperatures during reproduction in the zebra finch. We characterized the temperature within nests in a subtropical population of this species in relation to atmospheric temperature. Temperatures within nests frequently exceeded the level at which embryo’s develop optimally, even in the absence of parental incubation. We experimentally manipulated internal nest temperature to demonstrate that an average difference of 6°C in the nest temperature during the laying period reduced hatching time by an average of 3% of the total incubation time, owing to ‘ambient incubation’. Given the avian constraint of laying a single egg per day, the first eggs of a clutch are subject to prolonged effects of nest temperature relative to later laid eggs, potentially increasing hatching asynchrony. While birds may ameliorate the negative effects of ambient incubation on embryonic development by varying the location and design of their nests, high atmospheric temperatures are likely to constitute an important selective force on avian reproductive behaviour and physiology in subtropical and tropical regions, particularly in the light of predicted climate change that in many areas is leading to a higher frequency of hot days during the periods when birds breed. PMID:26998315

  10. Effects of ambient high temperature exposure on alumina-titania high emittance surfaces for solar dynamic systems

    SciTech Connect

    Groh, Kim K. de; Wheeler, Donald R.; Smith, Daniela C.; MacLachlan, Brian J.

    1999-01-22

    Solar dynamic (SD) space power systems require durable, high emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. To enhance surface characteristics, an alumina-titania coating has been applied to 500 heat receiver thermal energy containment canisters and the PLR of NASA Lewis Research Center's (LeRC) 2 kW SD ground test demonstrator (GTD). The alumina-titania coating was chosen because it had been found to maintain its high emittance under vacuum ({<=}10{sup -6} torr) at high temperatures (1457 deg. F (827 deg. C)) for an extended period ({approx_equal}2,700 hours). However, preflight verification of SD systems components, such as the PLR, require operation at ambient pressure and high temperatures. Therefore, the purpose of this research was to evaluate the durability of the alumina-titania coating at high temperature in air. Fifteen of sixteen alumina-titania coated Incoloy samples were exposed to high temperatures (600 deg. F (316 deg. C) to 1500 deg. F (816 deg. C)) for various durations (2 to 32 hours). Samples were characterized prior to, and after, heat treatment for reflectance, solar absorptance, room temperature emittance and emittance at 1200 deg. F (649 deg. C). Samples were also examined to detect physical defects and to determine surface chemistry using optical microscopy, scanning electron microscopy, operated with an energy dispersive spectroscopy (EDS) system, and x-ray photoelectron spectroscopy (XPS). Visual examination of the heat-treated samples showed a whitening of samples exposed to temperatures of 1000 deg. F (538 deg. C) and above. Correspondingly, the optical properties of these samples had degraded. A sample exposed to 1500 deg. F (816 deg. C) for 24 hours had whitened and the thermal emittance at 1200 deg. F (649 deg. C) had decreased from the non-heat treated value of 0.94 to 0.62. The coating on this sample had become embrittled, with spalling off

  11. Effects of Ambient High Temperature Exposure on Alumina-Titania High Emittance Surfaces for Solar Dynamic Systems

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Smith, Daniela C.; Wheeler, Donald R.; MacLachlam, Brian J.

    1998-01-01

    Solar dynamic (SD) space power systems require durable, high emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. To enhance surface characteristics, an alumina-titania coating has been applied to 500 heat receiver thermal energy containment canisters and the PLR of NASA Lewis Research Center's (LeRC) 2 kW SD ground test demonstrator (GTD). The alumina-titania coating was chosen because it had been found to maintain its high emittance under vacuum (less than or equal to 10(exp -6) torr) at high temperatures (1457 F (827 C)) for an extended period (approximately 2,700 hours). However, preflight verification of SD systems components, such as the PLR require operation at ambient pressure and high temperatures. Therefore, the purpose of this research was to evaluate the durability of the alumina-titania coating at high temperature in air. Fifteen of sixteen alumina-titania coated Incoloy samples were exposed to high temperatures (600 F (316 C) to l500 F (816 C)) for various durations (2 to 32 hours). Samples, were characterized prior to and after heat treatment for reflectance, solar absorptance, room temperature emittance and emittance at 1,200 F (649 C). Samples were also examined to detect physical defects and to determine surface chemistry using optical microscopy, scanning electron microscopy operated with an energy dispersive spectroscopy (EDS) system, and x ray photoelectron spectroscopy (XPS). Visual examination of the heat-treated samples showed a whitening of samples exposed to temperatures of 1,000 F (538 C) and above. Correspondingly, the optical properties of these samples had degraded. A sample exposed to 1,500 F (816 C) for 24 hours had whitened and the thermal emittance at 1,200 F (649 C) had decreased from the non-heat treated value of 0.94 to 0.62. The coating on this sample had become embrittled with spalling off the substrate noticeable at several locations. Based

  12. Distinct vasopressin content in the hypothalamic supraoptic and paraventricular nucleus of rats exposed to low and high ambient temperature.

    PubMed

    Jasnic, N; Dakic, T; Bataveljic, D; Vujovic, P; Lakic, I; Jevdjovic, T; Djurasevic, S; Djordjevic, J

    2015-08-01

    Both high and low ambient temperature represent thermal stressors that, among other physiological responses, induce activation of the hypothalamic-pituitary-adrenal (HPA) axis and secretion of arginine-vasopressin (AVP). The exposure to heat also leads to disturbance of osmotic homeostasis. Since AVP, in addition to its well-known peripheral effects, has long been recognized as a hormone involved in the modulation of HPA axis activity, the aim of the present study was to elucidate the hypothalamic AVP amount in the acutely heat/cold exposed rats. Rats were exposed to high (+38°C) or low (+4°C) ambient temperature for 60min. Western blot was employed for determining hypothalamic AVP levels, and the difference in its content between supraoptic (SON) and paraventricular nucleus (PVN) was detected using immunohistochemical analysis. The results showed that exposure to both high and low ambient temperature increased hypothalamic AVP levels, although the increment was higher under heat conditions. On the other hand, patterns of AVP level changes in PVN and SON were stressor-specific, given that exposure to cold increased the AVP level in both nuclei, while heat exposure affected the PVN AVP content alone. In conclusion, our results revealed that cold and heat stress influence hypothalamic AVP amount with different intensity. Moreover, different pattern of AVP amount changes in the PVN and SON indicates a role of this hormone not only in response to heat as an osmotic/physical threat, but to the non-osmotic stressors as well.

  13. High on/off current ratio in ballistic CNTFETs based on tuning the gate insulator parameters for different ambient temperatures

    NASA Astrophysics Data System (ADS)

    Shirazi, Shaahin G.; Mirzakuchaki, Sattar

    2013-11-01

    A theoretical study is presented on the on/off current ratio limits for a ballistic coaxially-gated carbon nanotube field effect transistor (CNTFET) with highly doped source/drain regions. Based on changes in gate insulator dielectric constant and thickness, the current ratio has been estimated at different ambient temperatures. Decreasing the gate insulator thickness after a certain value around 3 nm causes the current ratio to degrade drastically. Although the higher dielectric constant values have a fair effect on current ratio, this effect could be suppressed when the device with a low gate insulator thickness works at a low ambient temperature. The simulation results also show that the temperature drastically degrades the current ratio value; whereas in a certain range of ambient temperature, tuning the values of gate insulator thickness and dielectric constant could be very helpful. In this way, the optimum values of gate insulator thickness and dielectric constant are identified to offer the highest on/off current ratio of the device.

  14. Vitrification of high level nuclear waste inside ambient temperature disposal containers using inductive heating: The SMILE system

    SciTech Connect

    Powell, J.; Reich, M.; Barletta, R.

    1996-03-01

    A new approach, termed SMILE (Small Module Inductively Loaded Energy), for the vitrification of high level nuclear wastes (HLW) is described. Present vitrification systems liquefy the HLW solids and associated frit material in large high temperature melters. The molten mix is then poured into small ({approximately}1 m{sup 3}) disposal canisters, where it solidifies and cools. SMILE eliminates the separate, large high temperature melter. Instead, the BLW solids and frit melt inside the final disposal containers, using inductive heating. The contents then solidify and cool in place. The SMILE modules and the inductive heating process are designed so that the outer stainless can of the module remains at near ambient temperature during the process cycle. Module dimensions are similar to those of present disposal containers. The can is thermally insulated from the high temperature inner container by a thin layer of refractory alumina firebricks. The inner container is a graphite crucible lined with a dense alumina refractory that holds the HLW and fiit materials. After the SMILE module is loaded with a slurry of HLW and frit solids, an external multi-turn coil is energized with 30-cycle AC current. The enclosing external coil is the primary of a power transformer, with the graphite crucible acting as a single turn ``secondary.`` The induced current in the ``secondary`` heats the graphite, which in turn heats the HLW and frit materials. The first stage of the heating process is carried out at an intermediate temperature to drive off remnant liquid water and water of hydration, which takes about 1 day. The small fill/vent tube to the module is then sealed off and the interior temperature raised to the vitrification range, i.e., {approximately}1200C. Liquefaction is complete after approximately 1 day. The inductive heating then ceases and the module slowly loses heat to the environment, allowing the molten material to solidify and cool down to ambient temperature.

  15. Ambient Temperature Rechargeable Lithium Battery.

    DTIC Science & Technology

    1982-08-01

    AD-AI O297 EIC LA BS INC NEWTON MA F/6 10/3 AMB IENT TEMPERATURE RECHARGEABLE LITHIUM BATTERAU AG(MARHMU)L TI ARI AK IC07 UNCLASSIFIED C-655DEE TB6...036FL -T Research and Development Technical Report -N DELET-TR-81-0378-F AMBIENT TEMPERATURE RECHARGEABLE LITHIUM BATTERY K. M. Abraham D. L. Natwig...WORDS (Cenimne an revee filf Of ~"#amp Pu l41"lfr bg’ 61WA amober) Rechargeable lithium battery, CrO.5VO.5S2 positive electrode, 2Me-THF/LiAsF6, cell

  16. All-solid-state lithium-oxygen battery with high safety in wide ambient temperature range.

    PubMed

    Kitaura, Hirokazu; Zhou, Haoshen

    2015-08-21

    There is need to develop high energy storage devices with high safety to satisfy the growing industrial demands. Here, we show the potential to realize such batteries by assembling a lithium-oxygen cell using an inorganic solid electrolyte without any flammable liquid or polymer materials. The lithium-oxygen battery using Li1.575Al0.5Ge1.5(PO4)3 solid electrolyte was examined in the pure oxygen atmosphere from room temperature to 120 °C. The cell works at room temperature and first full discharge capacity of 1420 mAh g(-1) at 10 mA g(-1) (based on the mass of carbon material in the air electrode) was obtained. The charge curve started from 3.0 V, and that the majority of it lay below 4.2 V. The cell also safely works at high temperature over 80 °C with the improved battery performance. Furthermore, fundamental data of the electrochemical performance, such as cyclic voltammogram, cycle performance and rate performance was obtained and this work demonstrated the potential of the all-solid-state lithium-oxygen battery for wide temperature application as a first step.

  17. Anode for rechargeable ambient temperature lithium cells

    NASA Technical Reports Server (NTRS)

    Huang, Chen-Kuo (Inventor); Surampudi, Subbarao (Inventor); Attia, Alan I. (Inventor); Halpert, Gerald (Inventor)

    1994-01-01

    An ambient room temperature, high density, rechargeable lithium battery includes a Li(x)Mg2Si negative anode which intercalates lithium to form a single crystalline phase when x is up to 1.0 and an amorphous phase when x is from 1 to 2.0. The electrode has good reversibility and mechanical strength after cycling.

  18. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    SciTech Connect

    Abdelaziz, Omar; Shrestha, Som S.; Munk, Jeffrey D.; Linkous, Randall Lee; Goetzler, William; Guernsey, Matt; Kassuga, Theo

    2015-10-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

  19. Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    SciTech Connect

    Abdelaziz, Omar; Munk, Jeffrey D.; Shrestha, Som S.; Linkous, Randall Lee; Goetzler, William; Guernsey, Matt; Kassuga, Theo

    2015-08-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

  20. Influence of chestnut tannins on welfare, carcass characteristics, meat quality, and lipid oxidation in rabbits under high ambient temperature.

    PubMed

    Liu, Huawei; Zhou, Daowei; Tong, Jianming; Vaddella, Venkata

    2012-01-01

    A study was conducted to evaluate the influence of chestnut tannins (CT) on welfare, carcass characteristics, meat quality, and lipid oxidation in rabbits under high ambient temperature. Rabbits in one group were raised at 20°C and fed with basal diet (N) and other three groups (33°C) were fed basal diet with 0 (C), 5 (CT5), and 10 g (CT10) of CT/kg of diet. Compared with the C group, rabbits in CT10 had higher pH(24) and lower cooking loss and thiobarbituric acid reacting substance values at 0, 30, and 60 min of forced oxidation. Rabbits in C group had higher cortisol levels, creatine kinase activities, white blood cell counts, neutrophil percentage, neutrophil:lymphocyte ratio and lower T(3), T(4) levels, lymphocyte percentage than N and CT10 groups. Supplementation of CT seemed to have a positive effect on growth performance, welfare, and meat quality of rabbits under high ambient temperature.

  1. Stem juice production of the C4 sugarcane (Saccharum officinarum) is enhanced by growth at double-ambient CO2 and high temperature.

    PubMed

    Vu, Joseph C V; Allen, Leon H

    2009-07-15

    Two cultivars of sugarcane (Saccharum officinarum cv. CP73-1547 and CP88-1508) were grown for 3 months in paired-companion, temperature-gradient, sunlit greenhouses under daytime [CO2] of 360 (ambient) and 720 (double ambient) micromol mol(-1) and at temperatures of 1.5 degrees C (near ambient) and 6.0 degrees C higher than outside ambient temperature. Leaf area and biomass, stem biomass and juice and CO2 exchange rate (CER) and activities of ribulose bisphosphate carboxylase-oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC) of fully developed leaves were measured at harvest. On a main stem basis, leaf area, leaf dry weight, stem dry weight and stem juice volume were increased by growth at doubled [CO2] or high temperature. Such increases were even greater under combination of doubled [CO2]/high temperature. Plants grown at doubled [CO2]/high temperature combination averaged 50%, 26%, 84% and 124% greater in leaf area, leaf dry weight, stem dry weight and stem juice volume, respectively, compared with plants grown at ambient [CO2]/near-ambient temperature combination. In addition, plants grown at doubled [CO2]/high temperature combination were 2-3-fold higher in stem soluble solids than those at ambient [CO2]/near-ambient temperature combination. Although midday CER of fully developed leaves was not affected by doubled [CO2] or high temperature, plants grown at doubled [CO2] were 41-43% less in leaf stomatal conductance and 69-79% greater in leaf water-use efficiency, compared with plants grown at ambient [CO2]. Activity of PEPC was down-regulated 23-32% at doubled [CO2], while high temperature did not have a significant impact on this enzyme. Activity of Rubisco was not affected by growth at doubled [CO2], but was reduced 15-28% at high temperature. The increases in stem juice production and stem juice soluble solids concentration for sugarcane grown at doubled [CO2] or high temperature, or at doubled [CO2]/high temperature combination, were partially

  2. High Ambient Temperatures and Risk of Motor Vehicle Crashes in Catalonia, Spain (2000–2011): A Time-Series Analysis

    PubMed Central

    Escalera-Antezana, Juan Pablo; Dadvand, Payam; Llatje, Òscar; Barrera-Gómez, Jose; Cunillera, Jordi; Medina-Ramón, Mercedes; Pérez, Katherine

    2015-01-01

    Background Experimental studies have shown a decrease in driving performance at high temperatures. The epidemiological evidence for the relationship between heat and motor vehicle crashes is not consistent. Objectives We estimated the impact of high ambient temperatures on the daily number of motor vehicle crashes and, in particular, on crashes involving driver performance factors (namely distractions, driver error, fatigue, or sleepiness). Methods We performed a time-series analysis linking daily counts of motor vehicle crashes and daily temperature or occurrence of heat waves while controlling for temporal trends. All motor vehicle crashes with victims that occurred during the warm period of the years 2000–2011 in Catalonia (Spain) were included. Temperature data were obtained from 66 weather stations covering the region. Poisson regression models adjusted for precipitation, day of the week, month, year, and holiday periods were fitted to quantify the associations. Results The study included 118,489 motor vehicle crashes (an average of 64.1 per day). The estimated risk of crashes significantly increased by 2.9% [95% confidence interval (CI): 0.7%, 5.1%] during heat wave days, and this association was stronger (7.7%, 95% CI: 1.2%, 14.6%) when restricted to crashes with driver performance–associated factors. The estimated risk of crashes with driver performance factors significantly increased by 1.1% (95% CI: 0.1%, 2.1%) for each 1°C increase in maximum temperature. Conclusions Motor vehicle crashes involving driver performance–associated factors were increased in association with heat waves and increasing temperature. These findings are relevant for designing preventive plans in a context of global warming. Citation Basagaña X, Escalera-Antezana JP, Dadvand P, Llatje Ò, Barrera-Gómez J, Cunillera J, Medina-Ramón M, Pérez K. 2015. High ambient temperatures and risk of motor vehicle crashes in Catalonia, Spain (2000–2011): a time-series analysis

  3. A high-temperature, ambient-pressure ultra-dry operando reactor cell for Fourier-transform infrared spectroscopy.

    PubMed

    Köck, Eva-Maria; Kogler, Michaela; Pramsoler, Reinhold; Klötzer, Bernhard; Penner, Simon

    2014-08-01

    The construction of a newly designed high-temperature, high-pressure FT-IR reaction cell for ultra-dry in situ and operando operation is reported. The reaction cell itself as well as the sample holder is fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high-temperature zone. Special emphasis was put on chemically absolute water-free and inert experimental conditions, which includes reaction cell and gas-feeding lines. Operation and spectroscopy up to 1273 K is possible, as well as pressures up to ambient conditions. The reaction cell exhibits a very easy and variable construction and can be adjusted to any available FT-IR spectrometer. Its particular strength lies in its possibility to access and study samples under very demanding experimental conditions. This includes studies at very high temperatures, e.g., for solid-oxide fuel cell research or studies where the water content of the reaction mixtures must be exactly adjusted. The latter includes all adsorption studies on oxide surfaces, where the hydroxylation degree is of paramount importance. The capability of the reaction cell will be demonstrated for two selected examples where information and in due course a correlation to other methods can only be achieved using the presented setup.

  4. A high-temperature, ambient-pressure ultra-dry operando reactor cell for Fourier-transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Köck, Eva-Maria; Kogler, Michaela; Pramsoler, Reinhold; Klötzer, Bernhard; Penner, Simon

    2014-08-01

    The construction of a newly designed high-temperature, high-pressure FT-IR reaction cell for ultra-dry in situ and operando operation is reported. The reaction cell itself as well as the sample holder is fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high-temperature zone. Special emphasis was put on chemically absolute water-free and inert experimental conditions, which includes reaction cell and gas-feeding lines. Operation and spectroscopy up to 1273 K is possible, as well as pressures up to ambient conditions. The reaction cell exhibits a very easy and variable construction and can be adjusted to any available FT-IR spectrometer. Its particular strength lies in its possibility to access and study samples under very demanding experimental conditions. This includes studies at very high temperatures, e.g., for solid-oxide fuel cell research or studies where the water content of the reaction mixtures must be exactly adjusted. The latter includes all adsorption studies on oxide surfaces, where the hydroxylation degree is of paramount importance. The capability of the reaction cell will be demonstrated for two selected examples where information and in due course a correlation to other methods can only be achieved using the presented setup.

  5. Development of ceramic lithium-electrolyte based carbon dioxide sensors for temperatures ranging from ambient to high temperature

    NASA Astrophysics Data System (ADS)

    Lee, Inhee

    Solid-state electrochemical CO2 gas sensors composed of an electrolyte and two porous electrodes have been used extensively in the automobile and bio-chemical industry. Based on the field of application, the working temperature of the sensor ranges from room temperature to 600°C. Two potentiometric CO2 sensors that work at different temperature ranges were developed in this work. A potentiometric CO2 gas sensor with Li3PO 4 electrolyte and BaCO3 coated Li2CO3 sensing electrode was developed and the sensing electrode was characterized in order to understand its sensing mechanism under humid conditions. This potentiometric CO2 sensor showed humidity-interference-free sensing response for high CO2 concentrations (5˜25%) at high temperatures (T > 400°C). In addition, the sensor showed good reproducibility and long-term stability under humid conditions. In the sensing electrode, the BaCO 3 layer improved the resistance against humidity as a chemical barrier, while the inner Li2CO3 layer was responsible for the CO2 sensing. However, the sensor in which the eutectic layer covered the entire sensing electrode showed good sensing behavior under dry and humid conditions. Lately, low-temperature CO2 sensors have been attracting attention due to their low power consumption and easy sensor miniaturization, since a heater is unnecessary. We have developed a low-temperature CO2 sensor based on lithium lanthanum titanate (LLT) electrolyte in dry conditions that requires further improvement. Lithium lanthanum titanate (LLT) electrolytes were prepared by a conventional solid-state method. The impedance of the LLT electrolyte was measured over the temperature range of 300 to 473 K and the frequency range of 5 Hz and 13 MHz. Activation energies for the Li ionic conduction for grain boundary and grain were estimated to be 0.47 and 0.31 eV, respectively. It was found that LLT is a good ionic conductor at low temperatures and a good candidate as an electrolyte for low-temperature

  6. Effect of Mannheimia haemolytica pneumonia on behavior and physiologic responses of calves during high ambient environmental temperatures.

    PubMed

    Theurer, M E; Anderson, D E; White, B J; Miesner, M D; Mosier, D A; Coetzee, J F; Lakritz, J; Amrine, D E

    2013-08-01

    The objective of this study was to determine the effect of pneumonia during conditions of high (maximum ≥ 32°C) ambient temperatures on physiological and behavioral responses of calves. Eighteen black beef heifers averaging 240 kg were blocked by BW and randomly assigned to 1 of 2 treatment groups: 1) pneumonia induced by bronchoselective endoscopic inoculation with Mannheimia haemolytica (MH; n = 10) and 2) noninoculated controls (CN; n = 8). Nasal passage and rectal temperatures were measured every 2 h for 24 h after challenge and then twice daily for 9 d. Accelerometers, pedometers, and positioning devices monitored cattle behavior within the pen for 9 d after challenge. Blood samples were collected on trial d 0, 0.5, 1, 2, 3, 7, and 9 and were analyzed to determine the concentration of substance P, cortisol, haptoglobin, and metalloproteinase. All calves in the MH group were euthanized and necropsied on trial d 9. All MH calves became clinically ill postchallenge. A treatment × time interaction (P < 0.05) was evident for nasal and rectal temperatures, behavior, weight, and blood analysis. Rectal temperatures in MH were higher (P < 0.01) than CN during the period from 6 to 24 h after challenge. Conversely, nasal passage temperatures were less in MH calves compared with CN at 12 to 22 h after challenge. Calves in MH spent less time at the grain bunk, less time at the hay feeder, and more time lying down during the early pneumonia period compared with CN calves. Also, MH calves had significantly greater concentrations of blood biomarkers of pain (substance P) on d 0.5 (P < 0.01); stress (cortisol) on d 0.5 and 1 (P < 0.01); haptoglobin on d 0.5, 1, 2, 3, 7 (P < 0.01); and metalloproteinase on d 1, 2, and 3 (P < 0.01) compared with CN calves. At necropsy, all MH calves had right cranioventral bronchopneumonia (median lung lesions = 6.8%). Mannheimia haemolytica pneumonia caused significantly more changes in behavior and increased biomarkers during high (maximum

  7. Comparison of waste heat driven and electrically driven cooling systems for a high ambient temperature, off-grid application

    NASA Astrophysics Data System (ADS)

    Horvath, Christopher P.

    Forward army bases in off-grid locations with high temperatures require power and cooling capacity. Each gallon of fuel providing electrical power passes through a complex network, introducing issues of safety and reliability if this network is interrupted. Instead of using an engine and an electrically powered cooling system, a more efficient combined heat and power (CHP) configuration with a smaller engine and LiBr/Water absorption system (AS) powered by waste heat could be used. These two configurations were simulated in both steady state and transient conditions, in ambient temperatures up to 52°C, providing up to 3 kW of non-cooling electricity, and 5.3 kW of cooling. Unlike conventional AS's which crystallize at high temperatures and use bulky cooling towers, the proposed AS's avoid crystallization and have air-cooled HXs for portability. For the hottest transient week, the results showed fuel savings of 34-37%, weight reduction of 11-19%, and a volumetric footprint 3-10% smaller.

  8. Nocturnal loss of body reserves reveals high survival risk for subordinate great tits wintering at extremely low ambient temperatures.

    PubMed

    Krams, Indrikis; Cīrule, Dina; Vrublevska, Jolanta; Nord, Andreas; Rantala, Markus J; Krama, Tatjana

    2013-06-01

    Winter acclimatization in birds is a complex of several strategies based on metabolic adjustment accompanied by long-term management of resources such as fattening. However, wintering birds often maintain fat reserves below their physiological capacity, suggesting a cost involved with excessive levels of reserves. We studied body reserves of roosting great tits in relation to their dominance status under two contrasting temperature regimes to see whether individuals are capable of optimizing their survival strategies under extreme environmental conditions. We predicted less pronounced loss of body mass and body condition and lower rates of overnight mortality in dominant great tits at both mild and extremely low ambient temperatures, when ambient temperature dropped down to -43 °C. The results showed that dominant great tits consistently maintained lower reserve levels than subordinates regardless of ambient temperature. However, dominants responded to the rising risk of starvation under low temperatures by increasing their body reserves, whereas subdominant birds decreased reserve levels in harsh conditions. Yet, their losses of body mass and body reserves were always lower than in subordinate birds. None of the dominant great tits were found dead, while five young females and one adult female were found dead in nest boxes during cold spells when ambient temperatures dropped down to -43 °C. The dead great tits lost up to 23.83 % of their evening body mass during cold nights while surviving individuals lost on average 12.78 % of their evening body mass. Our results show that fattening strategies of great tits reflect an adaptive role of winter fattening which is sensitive to changes in ambient temperatures and differs among individuals of different social ranks.

  9. Selenium-enriched probiotics improve antioxidant status, immune function, and selenoprotein gene expression of piglets raised under high ambient temperature.

    PubMed

    Gan, Fang; Chen, Xingxiang; Liao, Shengfa F; Lv, Chenhui; Ren, Fei; Ye, Gengping; Pan, Cuiling; Huang, Da; Shi, Jun; Shi, Xiuli; Zhou, Hong; Huang, Kehe

    2014-05-21

    This research was conducted to evaluate the effects of selenium-enriched probiotics (SP) on growth performance, antioxidant status, immune function, and selenoprotein gene expression of piglets under natural high ambient temperature in summer. Forty-eight crossbred weanling piglets randomly allocated to four groups were fed for 42 days ad libitum a basal diet without (Con, 0.16 mg Se/kg) and with supplementation of probiotics (P, 0.16 mg Se/kg), sodium selenite (SS, 0.46 mg Se/kg), and SP (0.46 mg Se/kg). From each group, three piglets were randomly selected for blood collection on days 0, 14, 28, and 42 and tissue collection on day 42. The SP improved growth performance of piglets. Both SS and SP increased blood glutathione peroxidase activity and tissue thioredoxin reductase 1 mRNA expression, with SP being higher than SS. All P, SS, and SP supplementation increased the superoxide dismutase activity (40.1, 53.0, and 64.5%), glutathione content (84.6, 104, and 165%), TCR-induced T lymphocyte proliferation (20.8, 26.4, and 50.0%), and IL-2 concentration (24.9, 27.2, and 46.2%) and decreased malondialdehyde content (25.1, 26.3, and 49.3%), respectively. The greatest effects of SP supplementation suggest that SP may serve as a better feed additive than P or SS for piglets under high-temperature environments.

  10. Non-Contacting Finger Seals Static Performance Test Results at Ambient and High Temperatures

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2016-01-01

    The non-contacting finger seal is an advanced seal concept with potential to reduce specific fuel consumption in gas turbine engines by 2 to 3 percent with little to no wear of the seal or rotor. Static performance tests and bind-up tests of eight different non-contacting finger seal configurations were conducted in air at pressure differentials up to 689.4 kPa and temperatures up to 922 K. Four of the seals tested were designed to have lift pads concentric to a herringbone-grooved rotor which generates hydrodynamic lift when rotating. The remaining seals were tested with a smooth rotor; one seal had a circumferential taper and one had an axial taper on the lift pad inner diameter to create hydrodynamic lift during rotation. The effects of the aft finger axial thickness and of the forward finger inner diameter on leakage performance were investigated as well and compared to analytical predictions.

  11. Non-Contacting Finger Seals Static Performance Test Results at Ambient and High Temperatures

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2016-01-01

    The non-contacting finger seal is an advanced seal concept with potential to reduce specific fuel consumption in gas turbine engines by 2 to 3 with little to no wear of the seal or rotor. Static performance tests and bind-up tests of eight different non-contacting finger seal configurations were conducted in air at pressure differentials up to 689.4 kPa and temperatures up to 922 K. Four of the seals tested were designed to have lift pads concentric to a herringbone-grooved rotor which generates hydrodynamic lift when rotating. The remaining seals were tested with a smooth rotor; one seal had a circumferential taper and one had an axial taper on the lift pad inner diameter to create hydrodynamic lift during rotation. The effects of the aft finger axial thickness and of the forward finger inner diameter on leakage performance were investigated as well and compared to analytical predictions.

  12. High-Temperature Phase Transitions in CsH2PO4 Under Ambient and High-Pressure Conditions: A Synchrotron X-ray Diffraction Study

    SciTech Connect

    Botez,C.; Hermosillo, J.; Zhang, J.; Qian, J.; Zhao, Y.; Majzlan, J.; Chianelli, R.; Pantea, C.

    2007-01-01

    To clarify the microscopic origin of the temperature-induced three-order-of-magnitude jump in the proton conductivity of CsH2PO4 (superprotonic behavior), we have investigated its crystal structure modifications within the 25-300 C temperature range under both ambient- and high-pressure conditions using synchrotron x-ray diffraction. Our high-pressure data show no indication of the thermal decomposition/polymerization at the crystal surface recently proposed as the origin of the enhanced proton conductivity. Instead, we found direct evidence that the superprotonic behavior of the title material is associated with a polymorphic structural transition to a high-temperature cubic phase. Our results are in excellent agreement with previous high-pressure ac impedance measurements.

  13. Effect of season and high ambient temperature on activity levels and patterns of grizzly bears (Ursus arctos).

    PubMed

    McLellan, Michelle L; McLellan, Bruce N

    2015-01-01

    Understanding factors that influence daily and annual activity patterns of a species provides insights to challenges facing individuals, particularly when climate shifts, and thus is important in conservation. Using GPS collars with dual-axis motion sensors that recorded the number of switches every 5 minutes we tested the hypotheses: 1. Grizzly bears (Ursus arctos) increase daily activity levels and active bout lengths when they forage on berries, the major high-energy food in this ecosystem, and 2. Grizzly bears become less active and more nocturnal when ambient temperature exceeds 20°C. We found support for hypothesis 1 with both male and female bears being active from 0.7 to 2.8 h longer in the berry season than in other seasons. Our prediction under hypothesis 2 was not supported. When bears foraged on berries on a dry, open mountainside, there was no relationship between daily maximum temperature (which varied from 20.4 to 40.1°C) and the total amount of time bears were active, and no difference in activity levels during day or night between warm (20.4-27.3°C) and hot (27.9-40.1°C) days. Our results highlight the strong influence that food acquisition has on activity levels and patterns of grizzly bears and is a challenge to the heat dissipation limitation theory.

  14. Torpor at high ambient temperature in a neotropical didelphid, the grey short-tailed opossum (Monodelphis domestica).

    PubMed

    Busse, Sebastian; Lutter, Dominik; Heldmaier, Gerhard; Jastroch, Martin; Meyer, Carola W

    2014-11-01

    The grey short-tailed opossum, Monodelphis domestica, has been an established research animal for more than five decades, but relatively, little is known about its thermophysiology. Here we studied core body temperature (T b) and metabolic rate (MR) of female adult M. domestica housed in the laboratory at an ambient temperature (T a) of 26 °C. In expanding previous reports, the average recorded core T b of M. domestica was 34.3 °C. The T b of an individual M. domestica can drop below 30 °C (minimal T b: 28.6 °C) accompanied by a reduction in MR of up to 52 % even while having ad libitum access to food. These findings demonstrate for the first time the presence of spontaneous torpor in M. domestica. Metabolic suppression at relatively high T a and T b furthermore broadens our perspective on the use of torpor as a metabolic strategy not just restricted to cold climates.

  15. Torpor at high ambient temperature in a neotropical didelphid, the grey short-tailed opossum ( Monodelphis domestica)

    NASA Astrophysics Data System (ADS)

    Busse, Sebastian; Lutter, Dominik; Heldmaier, Gerhard; Jastroch, Martin; Meyer, Carola W.

    2014-11-01

    The grey short-tailed opossum, Monodelphis domestica, has been an established research animal for more than five decades, but relatively, little is known about its thermophysiology. Here we studied core body temperature ( T b) and metabolic rate (MR) of female adult M. domestica housed in the laboratory at an ambient temperature ( T a) of 26 °C. In expanding previous reports, the average recorded core T b of M. domestica was 34.3 °C. The T b of an individual M. domestica can drop below 30 °C (minimal T b: 28.6 °C) accompanied by a reduction in MR of up to 52 % even while having ad libitum access to food. These findings demonstrate for the first time the presence of spontaneous torpor in M. domestica. Metabolic suppression at relatively high T a and T b furthermore broadens our perspective on the use of torpor as a metabolic strategy not just restricted to cold climates.

  16. Electronic Ambient-Temperature Recorder

    NASA Technical Reports Server (NTRS)

    Russell, Larry; Barrows, William

    1995-01-01

    Electronic temperature-recording unit stores data in internal memory for later readout. Records temperatures from minus 40 degrees to plus 60 degrees C at intervals ranging from 1.875 to 15 minutes. With all four data channels operating at 1.875-minute intervals, recorder stores at least 10 days' data. For only one channel at 15-minute intervals, capacity extends to up to 342 days' data. Developed for recording temperatures of instruments and life-science experiments on satellites, space shuttle, and high-altitude aircraft. Adaptable to such terrestrial uses as recording temperatures of perishable goods during transportation and of other systems or processes over long times. Can be placed directly in environment to monitor.

  17. Coordination chemistry of Ti(IV) in silicate glasses and melts: III. Glasses and melts from ambient to high temperatures

    NASA Astrophysics Data System (ADS)

    Farges, François; Brown, Gordon E.; Navrotsky, Alexandra; Gan, Hao; Rehr, John R.

    1996-08-01

    The local structural environment of Ti in five Na-, K-, and Ca-titanosilicate glass/melts with TiO 2 concentrations ranging from 2.7-30.5 wt% has been determined by in situ Ti K-edge x-ray absorption fine structure (XAFS) spectroscopy at temperatures ranging from 293-1650 K. In parallel, two Ti-model compounds (Ni 2.6Ti 0.7O 4 spinel and TiO 2 rutile) were studied under the same conditions to better understand the effects of temperature (anharmonicity) on the XAFS spectra. Temperature-induced anharmonicity was found to vary, largely as a function of the Ti-coordination, and increases significantly around Ti with increasing temperature when present as [6]Ti. In contrast, anharmonicity appears negligible around [4]Ti at temperatures below 1200 K. We predict that anharmonicity should be weak around [5]Ti as well. No clear evidence was found for a significant change in the average nearest-neighbor coordination environment of Ti in the Na- and K-titanosilicate glasses and melts that exhibit anomalous heat capacities variations just above their glass transition temperatures, Tg (860-930 K). The small (predicted and measured) linear thermal expansion of the ( [5]TiO 2+) sbnd O bond in these systems at high temperature is expected to have an insignificant effect on the local environment of [5]Ti during the glass-to-supercooled liquid transition. In the most dilute Ti-glass studied (KS1; 2.7 wt% TiO 2), the local environment around [4]Ti (especially the second-neighbor alkalis) is relatively ordered at ambient temperature, but this order decreases dramatically above Tg. Lower quench rates appear to favor [4]Ti over [5]Ti. The origin of the observed anomalous positive variations in heat capacities of these melts may be related to significant changes in the medium-range environment around Ti above Tg including the disappearance of percolation domains involving interfaces between alkali-rich and network-former rich regions during structural relaxation at Tg; these percolation

  18. Patients presenting with miliaria while wearing flame resistant clothing in high ambient temperatures: a case series

    PubMed Central

    2011-01-01

    Introduction Clothing can be a cause of occupational dermatitis. Frequent causes of clothing-related dermatological problems can be the fabric itself and/or chemical additives used in the laundering process, friction from certain fabrics excessively rubbing the skin, or heat retention from perspiration-soaked clothing in hot working environments. To the best of our knowledge, these are the first reported cases of miliaria rubra associated with prolonged use of flame resistant clothing in the medical literature. Case presentation We report 18 cases (14 men and 4 women, with an age range of 19 to 37 years) of moderate to severe skin irritation associated with wearing flame resistant clothing in hot arid environments (temperature range: 39 to 50°C, 5% to 25% relative humidity). We describe the medical history in detail of a 23-year-old Caucasian woman and a 31-year-old African-American man. A summary of the other 16 patients is also provided. Conclusions These cases illustrate the potential serious nature of miliaria with superimposed Staphylococcus infections. All 18 patients fully recovered with topical skin treatment and modifications to their dress ensemble. Clothing, in particular blend fabrics, must be thoroughly laundered to adequately remove detergent residue. While in hot environments, individuals with sensitive skin should take the necessary precautions such as regular changing of clothing and good personal hygiene to ensure that their skin remains as dry and clean as possible. It is also important that they report to their health care provider as soon as skin irritation or rash appears to initiate any necessary medical procedures. Miliaria rubra can take a week or longer to clear, so removal of exposure to certain fabric types may be necessary. PMID:21939537

  19. The effects of feed restriction and ambient temperature on growth and ascites mortality of broilers reared at high altitude.

    PubMed

    Ozkan, S; Takma, C; Yahav, S; Sögüt, B; Türkmut, L; Erturun, H; Cahaner, A

    2010-05-01

    The development of ascites was investigated in broilers at low versus high altitudes, cold versus normal ambient temperatures (AT), and 3 feeding regimens. One-day-old chicks obtained at sea level were reared at high altitude (highA; 1,720 m; n = 576) with 2 AT treatments, low AT from 3 wk onward at highA (highA/cold) and normal AT from 3 wk onward at highA (highA/norm), or at sea level (normal AT from 3 wk onward at low altitude, lowA/norm; n = 540). Under highA/cold, AT ranged between 16 to 17 degrees C in the fourth week, 17 to 19 degrees C in the fifth week, and 19 to 21 degrees C thereafter. Under highA/norm and lowA/norm, AT was 24 degrees C in the fourth week and ranged between 22 to 24 degrees C thereafter. Broilers in each condition were divided into 3 groups: feed restriction (FR) from 7 to 14 d, FR from 7 to 21 d, and ad libitum (AL). Ascites mortality and related parameters were recorded. Low mortality (0.4%) occurred under lowA/norm conditions. Under highA/norm, mortality was lower in females (8.6%) than in males (13.8%) and was not affected by the feeding regimen. The highA/cold treatment resulted in higher mortality but only in males; it was 44.2% among highA/cold AL-fed males and only about 26% under the FR regimens, suggesting that FR helped some males to better acclimatize to the highA/cold environment and avoid ascites. However, mortality was only 13.3% in AL-fed males at highA/norm and FR did not further reduce the incidence of ascites under these conditions. Thus, avoiding low AT in the poultry house by slight heating was more effective than FR in reducing ascites mortality at highA. Compared with FR from 7 to 14 d, FR from 7 to 21 d did not further reduce mortality and reduced growth. At 47 d, the majority of surviving broilers at highA had high levels of hematocrit and right ventricle:total ventricle weight ratio (>0.29), but they were healthy and reached approximately the same BW as their counterparts at low altitude. This finding may

  20. Influence of fish meal and supplemental fat on performance of finishing steers exposed to moderate or high ambient temperatures.

    PubMed

    White, T W; Bunting, L D; Sticker, L S; Hembry, F G; Saxton, A M

    1992-11-01

    Ninety-six Hereford x Angus steers (mean initial BW = 295 kg) were used in two growth experiments conducted at moderate and high ambient temperatures (AT), 48 steers per AT. Within each AT, calves were assigned to six dietary treatments consisting of a basal diet (approximately 60% corn and 20% grass hay) supplemented with either 0, 2.5, or 5% fat and with either soybean meal (SBM) or Menhaden fish meal (FM) included at levels such that a ratio of 16.3 kcal of NEm per kilogram of CP was maintained. Blood and ruminal fluid were collected 40 d before slaughter. During the final 28 d of the moderate AT experiment, apparent digestibility of dietary components was measured in four individually fed steers from each dietary treatment. Steer ADG was not affected by fat, and DMI and efficiency of gain were not affected (P > .10) by treatment. Average daily gain was lower for steers fed FM than for those fed SBM at moderate AT but higher at high AT (CP source x AT interaction; P < .05). Ruminal ratio of acetate to propionate declined linearly with increasing fat at moderate AT but was not affected by fat at high AT (fat x AT interaction trend; P = .08). Plasma urea N concentration increased linearly (P < .05) with increasing fat and was higher (P < .05) in steers kept at high than in those kept at moderate AT. Although apparent digestibility was not altered in steers fed FM, DM and NDF (P < .05) and ADF (P = .07) digestibility decreased with increasing fat in steers fed SBM (CP source x fat interaction).(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Effects Investigated of Ambient High-Temperature Exposure on Alumina-Titania High-Emittance Surfaces for Solar Dynamic Systems

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Smith, Daniela C.

    1999-01-01

    Solar-dynamic space power systems require durable, high-emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. An alumina-titania coating, which has been evaluated for solar-dynamic heat receiver canister applications, has been chosen for a PLR application (an electrical sink for excess power from the turboalternator/compressor) because of its demonstrated high emittance and high-temperature durability in vacuum. Under high vacuum conditions (+/- 10(exp -6) torr), the alumina-titania coating was found to be durable at temperatures of 1520 F (827 C) for approx. 2700 hours with no degradation in optical properties. This coating has been successfully applied to the 2-kW solar-dynamic ground test demonstrator at the NASA Lewis Research Center, to the 500 thermal-energy-storage containment canisters inside the heat receiver and to the PLR radiator. The solar-dynamic demonstrator has successfully operated for over 800 hours in Lewis large thermal/vacuum space environment facility, demonstrating the feasibility of solar-dynamic power generation for space applications.

  2. Vitamin E and organic selenium enhances the antioxidative status and quality of chicken semen under high ambient temperature.

    PubMed

    Ebeid, T A

    2012-01-01

    1. The effects of supplemental dietary vitamin E and organic selenium (Se), and their combination, on improving semen quality characteristics and antioxidative status were investigated in cockerels exposed to high ambient temperature. 2. A total of 36 Egyptian local cross males, 40 weeks old, were housed individually in cages in an open-sided building (average daily temperature ranged from 33 to 36°C and relative humidity from 60 to 70%). Birds were divided randomly into 4 experimental treatments (n=9 each): (1) control (basal diet without any supplementation with vitamin E or Se); (2) vitamin E (basal diet +200 mg α-tocopherol acetate/kg diet); (3) Se (basal diet +0.3 mg organic Se/kg diet); and (4) vitamin E+Se (basal diet +200 mg α-tocopherol acetate/kg diet +0.3 mg organic Se/kg diet). 3. Under heat stress conditions, inclusion of vitamin E and/or organic Se in the diets enhanced the semen quality traits, including the spermatozoa count and motility, and reduced the percentage of dead spermatozoa. 4. A combination of 200 mg/kg vitamin E with 0.3 mg/kg organic Se reduced the thiobarbituric acid reactive substance concentration in seminal plasma samples to about 28% of the controls; and also enhanced the seminal plasma glutathione peroxidase activity by two-fold compared with controls. 5. It was concluded that dietary vitamin E in combination with organic Se has a synergistic effect in minimising lipid peroxidation and improving the antioxidative status in seminal plasma of the domestic fowl, which probably translated into enhanced spermatozoa count, motility and reduced percentage of dead spermatozoa under heat stress conditions.

  3. Effects of grouping unfamiliar cohorts, high ambient temperature and stocking density on live performance of growing pigs.

    PubMed

    Kerr, C A; Giles, L R; Jones, M R; Reverter, A

    2005-04-01

    high-density counterparts (9.04 +/- 0.38 vs. 7.49 +/- 0.29 kg). In conclusion, under the conditions of this study, the grouping of unfamiliar cohorts and high ambient temperature treatments had a detrimental effect on pig performance, and these effects were reversible.

  4. Tailpipe emissions from gasoline direct injection (GDI) and port fuel injection (PFI) vehicles at both low and high ambient temperatures.

    PubMed

    Zhu, Rencheng; Hu, Jingnan; Bao, Xiaofeng; He, Liqiang; Lai, Yitu; Zu, Lei; Li, Yufei; Su, Sheng

    2016-09-01

    Vehicle emissions are greatly influenced by various factors that are related to engine technology and driving conditions. Only the fuel injection method and ambient temperature are investigated in this research. Regulated gaseous and particulate matter (PM) emissions from two advanced gasoline-fueled vehicles, one with direct fuel injection (GDI) and the other with port fuel injection (PFI), are tested with conventional gasoline and ethanol-blended gasoline (E10) at both -7 °C and 30 °C. The total particle number (PN) concentrations and size distributions are monitored with an Electrical Low Pressure Impactor (ELPI(+)). The solid PN concentrations are measured with a condensation particle counter (CPC) after removing volatile matters through the particle measurement program (PMP) system. The results indicate that decreasing the ambient temperature from 30 °C to -7 °C significantly increases the fuel consumption and all measured emissions except for NOx. The GDI vehicle exhibits lower fuel consumption than the PFI vehicle but emits more total hydrocarbons (THC), PM mass and solid PN emissions at 30 °C. The adaptability of GDI technology appears to be better than that of PFI technology at low ambient temperature. For example, the CO, THC and PM mass emission factors of the PFI vehicle are higher than those of the GDI vehicle and the solid PN emission factors are comparable in the cold-start tests at -7 °C. Specifically, during start-up the particulate matter emissions of the PFI are much higher than the GDI. In most cases, the geometric mean diameter (GMD) of the accumulation mode particles is 58-86 nm for both vehicles, and the GMD of the nucleation mode particles is 10-20 nm. The results suggest that the gaseous and particulate emissions from the PFI vehicle should not be neglected compared to those from the GDI vehicle especially in a cold environment.

  5. Simple Fabrication of Mesoporous Silica with Remarkable High Temperature Stability at Neutral pH and Ambient Conditions from TEOS

    NASA Astrophysics Data System (ADS)

    Hess, David; Vippagunta, Radha; Watkins, James

    2007-03-01

    Traditional silica synthesis processes can yield well ordered materials, but the synthesis conditions also lead to incomplete condensation of the silica network, which results in significant structural contraction upon calcination and limited thermal, hydrothermal and mechanical stability. Here we report the synthesis that, surprisingly, yields nearly complete condensation of the silica network (virtually all Q4 linkages) using cysteamine as the catalyst and polyoxyethylene surfactants as the structure directing agents in buffered solution at neutral pH and ambient temperature. Recently, small molecule bifunctional amines, including cysteamine, were evaluated by Morse and co-workers and found to produce silica from TEOS(JACS 2005, 127, 35). Our work combines the cysteamine catalyst system with structure-directing block copolymer surfactants at neutral pH and ambient temperature to produce mesoporous silica. The addition of tetraethyl orthosilicate (TEOS) to a solution of containing cysteamine, citrate buffer (pH 7.2) and 5wt Brij amphiphilic block copolymer (polyethylene oxide-polyethylene) yields mesoporous silica. The resulting mesoporous silica powder was analyzed using XRD, TGA, FTIR, TEM, and NMR. The materials were found to exhibit stability under extreme temperature calcinations (up to 800 C) in the presence of water. SAXS shows that 1.0 shrinkage upon calcination up to 800C. 29Si NMR analysis indicates a fully condensed silica network, Q4 linkages, in accordance with this observation.

  6. Part 2. Association of daily mortality with ambient air pollution, and effect modification by extremely high temperature in Wuhan, China.

    PubMed

    Qian, Zhengmin; He, Qingci; Lin, Hung-Mo; Kong, Lingli; Zhou, Dunjin; Liang, Shengwen; Zhu, Zhichao; Liao, Duanping; Liu, Wenshan; Bentley, Christy M; Dan, Jijun; Wang, Beiwei; Yang, Niannian; Xu, Shuangqing; Gong, Jie; Wei, Hongming; Sun, Huilin; Qin, Zudian

    2010-11-01

    Fewer studies have been published on the association between daily mortality and ambient air pollution in Asia than in the United States and Europe. This study was undertaken in Wuhan, China, to investigate the acute effects of air pollution on mortality with an emphasis on particulate matter (PM*). There were three primary aims: (1) to examine the associations of daily mortality due to all natural causes and daily cause-specific mortality (cardiovascular [CVD], stroke, cardiac [CARD], respiratory [RD], cardiopulmonary [CP], and non-cardiopulmonary [non-CP] causes) with daily mean concentrations (microg/m3) of PM with an aerodynamic diameter--10 pm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), or ozone (O3); (2) to investigate the effect modification of extremely high temperature on the association between air pollution and daily mortality due to all natural causes and daily cause-specific mortality; and (3) to assess the uncertainty of effect estimates caused by the change in International Classification of Disease (ICD) coding of mortality data from Revision 9 (ICD-9) to Revision 10 (ICD-10) code. Wuhan is called an "oven city" in China because of its extremely hot summers (the average daily temperature in July is 37.2 degrees C and maximum daily temperature often exceeds 40 degrees C). Approximately 4.5 million residents live in the core city area of 201 km2, where air pollution levels are higher and ranges are wider than the levels in most cities studied in the published literature. We obtained daily mean levels of PM10, SO2, and NO2 concentrations from five fixed-site air monitoring stations operated by the Wuhan Environmental Monitoring Center (WEMC). O3 data were obtained from two stations, and 8-hour averages, from 10:00 to 18:00, were used. Daily mortality data were obtained from the Wuhan Centres for Disease Prevention and Control (WCDC) during the study period of July 1, 2000, to June 30, 2004. To achieve the first aim, we used a regression of

  7. Stem juice production of the C4 sugarcane (Saccharum officinarum)is enhanced by growth at double-ambient CO2 and high temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four sugarcane cultivars were grown for three months in sunlit greenhouses under [CO2] of 360 (ambient) and 720(doubled) ppm and at temperatures (T) of 1.5 (near ambient) and 6.0C higher than outside ambient T. Leaf area, stem juice, plant biomass, leaf CO2 exchange rate (CER) and activities of PEP ...

  8. Ambient Temperature Phase Change Launcher

    DTIC Science & Technology

    2013-09-30

    limited to, carbon dioxide, nitrogen, argon, neon , helium , nitrous oxide, carbon monoxide or xenon. [0023] For example, carbon dioxide has an...tank 12 which stores atmospheric gas such as carbon dioxide, nitrogen, argon, neon , helium , nitrous oxide, carbon monoxide or xenon at high pressure

  9. High Temperatures Enhanced Acute Mortality Effects of Ambient Particle Pollution in the “Oven” City of Wuhan, China

    PubMed Central

    Qian, Zhengmin; He, Qingci; Lin, Hung-Mo; Kong, Lingli; Bentley, Christy M.; Liu, Wenshan; Zhou, Dunjin

    2008-01-01

    Background We investigated whether the effect of air pollution on daily mortality is enhanced by high temperatures in Wuhan, China, using data from 2001 to 2004. Wuhan has been called an “oven” city because of its hot summers. Approximately 4.5 million permanent residents live in the 201-km2 core area of the city. Method We used a generalized additive model to analyze pollution, mortality, and covariate data. The estimates of the interaction between high temperature and air pollution were obtained from the main effects and pollutant–temperature interaction models. Results We observed effects of consistently and statistically significant interactions between particulate matter ≤ 10 μm (PM10) and temperature on daily nonaccidental (p = 0.014), cardiovascular (p = 0.007), and cardiopulmonary (p = 0.014) mortality. The PM10 effects were strongest on extremely high-temperature days (daily average temperature, 33.1°C), less strong on extremely low-temperature days (2.2°C), and weakest on normal-temperature days (18.0°C). The estimates of the mean percentage of change in daily mortality per 10-μg/m3 increase in PM10 concentrations at the average of lags 0 and 1 day during hot temperature were 2.20% (95% confidence interval), 0.74–3.68) for nonaccidental, 3.28% (1.24–5.37) for cardiovascular, 2.35% (−0.03 to 4.78) for stroke, 3.31% (−0.22 to 6.97) for cardiac, 1.15% (−3.54% to 6.07) for respiratory, and 3.02% (1.03–5.04) for cardiopulmonary mortality. Conclusions We found synergistic effects of PM10 and high temperatures on daily nonaccidental, cardiovascular, and cardiopulmonary mortality in Wuhan. PMID:18795159

  10. All inorganic ambient temperature rechargeable lithium battery

    NASA Astrophysics Data System (ADS)

    Kuo, H. C.; Dey, A. N.; Schlaikjer, C.; Foster, D.; Kallianidis, M.

    Research and development was carried out on ambient-temperature rechargeable lithium batteries with inorganic SO2 electrolytes. The following solutes in SO2 were studied: tetrachloroaluminates, LiAlCl4, Li2B10Cl10, and LiGaCl4. Copper chloride (CuCl2) was used as one of the electrode materials.

  11. Near-ambient pressure XPS of high-temperature surface chemistry in Sr2Co2O5 thin films

    DOE PAGES

    Hong, Wesley T.; Stoerzinger, Kelsey; Crumlin, Ethan J.; ...

    2016-02-11

    Transition metal perovskite oxides are promising electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells, but a lack of fundamental understanding of oxide surfaces impedes the rational design of novel catalysts with improved device efficiencies. In particular, understanding the surface chemistry of oxides is essential for controlling both catalytic activity and long-term stability. Thus, elucidating the physical nature of species on perovskite surfaces and their catalytic enhancement would generate new insights in developing oxide electrocatalysts. In this article, we perform near-ambient pressure XPS of model brownmillerite Sr2Co2O5 (SCO) epitaxial thin films with different crystallographic orientations. Detailed analysis of themore » Co 2p spectra suggests that the films lose oxygen as a function of temperature. Moreover, deconvolution of the O 1s spectra shows distinct behavior for (114)-oriented SCO films compared to (001)-oriented SCO films, where an additional bulk oxygen species is observed. These findings indicate a change to a perovskite-like oxygen chemistry that occurs more easily in (114) SCO than (001) SCO, likely due to the orientation of oxygen vacancy channels out-of-plane with respect to the film surface. This difference in surface chemistry is responsible for the anisotropy of the oxygen surface exchange coefficient of SCO and may contribute to the enhanced ORR kinetics of La0.8Sr0.2CoO3-δ thin films by SCO surface particles observed previously.« less

  12. Ambient temperature modelling with soft computing techniques

    SciTech Connect

    Bertini, Ilaria; Ceravolo, Francesco; Citterio, Marco; Di Pietra, Biagio; Margiotta, Francesca; Pizzuti, Stefano; Puglisi, Giovanni; De Felice, Matteo

    2010-07-15

    This paper proposes a hybrid approach based on soft computing techniques in order to estimate monthly and daily ambient temperature. Indeed, we combine the back-propagation (BP) algorithm and the simple Genetic Algorithm (GA) in order to effectively train artificial neural networks (ANN) in such a way that the BP algorithm initialises a few individuals of the GA's population. Experiments concerned monthly temperature estimation of unknown places and daily temperature estimation for thermal load computation. Results have shown remarkable improvements in accuracy compared to traditional methods. (author)

  13. High-T(sub c) Superconductor-Normal-Superconductor Junctions with Polyimide-Passivated Ambient Temperature Edge Formation

    NASA Technical Reports Server (NTRS)

    Barner, J. B.; Kleinsasser, A. W.; Hunt, B. D.

    1996-01-01

    The ability to controllably fabricate High-Temperature Superconductor (HTS) S-Normal-S (SNS) Josephson Juntions (JJ's) enhances the possibilities fro many applications, including digital circuits, SQUID's, and mixers. A wide variety of approaches to fabricating SNS-like junctions has been tried and analyzed in terms of proximity effect behavior.

  14. Near-ambient pressure XPS of high-temperature surface chemistry in Sr2Co2O5 thin films

    SciTech Connect

    Hong, Wesley T.; Stoerzinger, Kelsey; Crumlin, Ethan J.; Mutoro, Eva; Jeen, Hyoung Jeen; Lee, Ho Nyung; Shao-Horn, Yang

    2016-02-11

    Transition metal perovskite oxides are promising electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells, but a lack of fundamental understanding of oxide surfaces impedes the rational design of novel catalysts with improved device efficiencies. In particular, understanding the surface chemistry of oxides is essential for controlling both catalytic activity and long-term stability. Thus, elucidating the physical nature of species on perovskite surfaces and their catalytic enhancement would generate new insights in developing oxide electrocatalysts. In this article, we perform near-ambient pressure XPS of model brownmillerite Sr2Co2O5 (SCO) epitaxial thin films with different crystallographic orientations. Detailed analysis of the Co 2p spectra suggests that the films lose oxygen as a function of temperature. Moreover, deconvolution of the O 1s spectra shows distinct behavior for (114)-oriented SCO films compared to (001)-oriented SCO films, where an additional bulk oxygen species is observed. These findings indicate a change to a perovskite-like oxygen chemistry that occurs more easily in (114) SCO than (001) SCO, likely due to the orientation of oxygen vacancy channels out-of-plane with respect to the film surface. This difference in surface chemistry is responsible for the anisotropy of the oxygen surface exchange coefficient of SCO and may contribute to the enhanced ORR kinetics of La0.8Sr0.2CoO3-δ thin films by SCO surface particles observed previously.

  15. Ambient-temperature co-oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T.; Schryer, David R.; Brown, Kenneth G.; Kielin, Erik J.

    1991-01-01

    Oxidation catalysts which operate at ambient temperature were developed for the recombination of carbon monoxide (CO) and oxygen (O2) dissociation products which are formed during carbon dioxide (CO2) laser operation. Recombination of these products to regenerate CO2 allows continuous operation of CO2 lasers in a closed cycle mode. Development of these catalyst materials provides enabling technology for the operation of such lasers from space platforms or in ground based facilities without constant gas consumption required for continuous open cycle operation. Such catalysts also have other applications in various areas outside the laser community for removal of CO from other closed environments such as indoor air and as an ambient temperature catalytic converter for control of auto emissions.

  16. Ambient temperature sodium-sulfur batteries.

    PubMed

    Manthiram, Arumugam; Yu, Xingwen

    2015-05-13

    Ambient- or room-temperature sodium-sulfur batteries (RT Na-S) are gaining much attention as a low-cost option for large-scale electrical energy storage applications. However, their adoption is hampered by severe challenges. This concept paper summarizes first the operating principles, history, recent progress, and challenges of RT Na-S battery technology, and then suggests future directions towards enhancing performance in order for it to be a viable technology.

  17. Rapid characterization of lithium ion battery electrolytes and thermal aging products by low-temperature plasma ambient ionization high-resolution mass spectrometry.

    PubMed

    Vortmann, Britta; Nowak, Sascha; Engelhard, Carsten

    2013-03-19

    Lithium ion batteries (LIBs) are key components for portable electronic devices that are used around the world. However, thermal decomposition products in the battery reduce its lifetime, and decomposition processes are still not understood. In this study, a rapid method for in situ analysis and reaction monitoring in LIB electrolytes is presented based on high-resolution mass spectrometry (HR-MS) with low-temperature plasma probe (LTP) ambient desorption/ionization for the first time. This proof-of-principle study demonstrates the capabilities of ambient mass spectrometry in battery research. LTP-HR-MS is ideally suited for qualitative analysis in the ambient environment because it allows direct sample analysis independent of the sample size, geometry, and structure. Further, it is environmental friendly because it eliminates the need of organic solvents that are typically used in separation techniques coupled to mass spectrometry. Accurate mass measurements were used to identify the time-/condition-dependent formation of electrolyte decomposition compounds. A LIB model electrolyte containing ethylene carbonate and dimethyl carbonate was analyzed before and after controlled thermal stress and over the course of several weeks. Major decomposition products identified include difluorophosphoric acid, monofluorophosphoric acid methyl ester, monofluorophosphoric acid dimethyl ester, and hexafluorophosphate. Solvents (i.e., dimethyl carbonate) were partly consumed via an esterification pathway. LTP-HR-MS is considered to be an attractive method for fundamental LIB studies.

  18. Ambient air temperature effects on the temperature of sewage sludge composting process.

    PubMed

    Huang, Qi-fei; Chen, Tong-bin; Gao, Ding; Huang, Ze-chun

    2005-01-01

    Using data obtained with a full-scale sewage sludge composting facility, this paper studied the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Two volume ratios were examined experimentally, 1: 0: 1 and 3: 1: 2. The results show that composting temperature was influenced by ambient air temperature and the influence was more significant when composting was in the temperature rising process: composting temperature changed 2.4-6.5 degrees C when ambient air temperature changed 13 degrees C. On the other hand, the influence was not significant when composting was in the high-temperature and/or temperature falling process: composting temperature changed 0.75-1.3 degrees C when ambient air temperature changed 8-15 degrees C. Hysteresis effect was observed in composting temperature's responses to ambient air temperature. When the ventilation capability of pile was excellent (at a volume ratio of 1:0:1), the hysteresis time was short and ranging 1.1-1.2 h. On the contrary, when the proportion of added bulking agent was low, therefore less porosity in the substrate (at a volume ratio of 3:1:2), the hysteresis time was long and ranging 1.9-3.1 h.

  19. Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response.

    PubMed

    Ghasemi, Hossein Ali; Ghasemi, Rohollah; Torki, Mehran

    2014-09-01

    This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions.During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70% (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.

  20. Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response

    NASA Astrophysics Data System (ADS)

    Ghasemi, Hossein Ali; Ghasemi, Rohollah; Torki, Mehran

    2014-09-01

    This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions. During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70 % (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.

  1. The Combined Effect of High Ambient Temperature and Antihypertensive Treatment on Renal Function in Hospitalized Elderly Patients

    PubMed Central

    Novack, Victor; Rogachev, Boris; Haviv, Yosef S.; Barski, Leonid

    2016-01-01

    Background The aging kidney manifests structural, functional as well as pharmacological changes, rendering elderly patients more susceptible to adverse environmental influences on their health, dehydration in particular. Hypothesis Higher temperature is associated with renal function impairment in patients 65 years and older who routinely take thiazide and/or ACE-inhibitors/ARBs. Methods We obtained health data of patients older than 65 who were admitted to a large tertiary center during the years 2006–2011, with a previous diagnosis of hypertension, and treated with thiazide, ACE-inhibitors/ARBs or both. We collected environmental data of daily temperature, available from collaborative public and governmental institutions. In order to estimate the effect of daily temperature on renal function we performed linear mixed models, separately for each treatment group and creatinine change during hospital admission. Results We identified 26,286 admissions for 14, 268 patients with a mean age of 75.6 (±6.9) years, of whom 53.6% were men. Increment in daily temperature on admission of 5°C had significant effect on creatinine increase in the no treatment (baseline creatinine adjusted 0.824 mg/dL, % change 1.212, % change 95% C.I 0.082–2.354) and dual treatment groups (baseline creatinine adjusted 1.032mg/dL, % change 3.440, % change 95% C.I 1.227–5.700). Sub-analysis stratified by advanced age, chronic kidney disease and primary diagnosis on hospital admission, revealed a significant association within patients admitted due to acute infection and treated with dual therapy. Conclusion Whereas previous studies analyzed sporadic climate effects during heat waves and/or excluded older population taking anti-hypertensive medications, the present study is novel by showing a durable association of temperature and decreased renal function specifically in elderly patients taking anti-hypertensive medications. PMID:27992525

  2. In Situ Ptychography of Heterogeneous Catalysts using Hard X-Rays: High Resolution Imaging at Ambient Pressure and Elevated Temperature.

    PubMed

    Baier, Sina; Damsgaard, Christian D; Scholz, Maria; Benzi, Federico; Rochet, Amélie; Hoppe, Robert; Scherer, Torsten; Shi, Junjie; Wittstock, Arne; Weinhausen, Britta; Wagner, Jakob B; Schroer, Christian G; Grunwaldt, Jan-Dierk

    2016-02-01

    A new closed cell is presented for in situ X-ray ptychography which allows studies under gas flow and at elevated temperature. In order to gain complementary information by transmission and scanning electron microscopy, the cell makes use of a Protochips E-chipTM which contains a small, thin electron transparent window and allows heating. Two gold-based systems, 50 nm gold particles and nanoporous gold as a relevant catalyst sample, were used for studying the feasibility of the cell. Measurements showing a resolution around 40 nm have been achieved under a flow of synthetic air and during heating up to temperatures of 933 K. An elevated temperature exhibited little influence on image quality and resolution. With this study, the potential of in situ hard X-ray ptychography for investigating annealing processes of real catalyst samples is demonstrated. Furthermore, the possibility to use the same sample holder for ex situ electron microscopy before and after the in situ study underlines the unique possibilities available with this combination of electron microscopy and X-ray microscopy on the same sample.

  3. PLUG-IN HYBRID ELECTRIC VEHICLE AND HYBRID ELECTRIC VEHICLE EMISSIONS UNDER FTP AND US06 CYCLES AT HIGH, AMBIENT, AND LOW TEMPERATURES

    SciTech Connect

    Seidman, M.R.; Markel, T.

    2008-01-01

    The concept of a Plug-in Hybrid Electric Vehicle (PHEV) is to displace consumption of gasoline by using electricity from the vehicle’s large battery pack to power the vehicle as much as possible with minimal engine operation. This paper assesses the PHEV emissions and operation. Currently, testing of vehicle emissions is done using the federal standard FTP4 cycle on a dynamometer at ambient (75°F) temperatures. Research was also completed using the US06 cycle. Furthermore, research was completed at high (95°F) and low (20°F) temperatures. Initial dynamometer testing was performed on a stock Toyota Prius under the standard FTP4 cycle, and the more demanding US06 cycle. Each cycle was run at 95°F, 75°F, and 20°F. The testing was repeated with the same Prius retrofi tted with an EnergyCS Plug-in Hybrid Electric system. The results of the testing confi rm that the stock Prius meets Super-Ultra Low Emission Vehicle requirements under current testing procedures, while the PHEV Prius under current testing procedures were greater than Super-Ultra Low Emission Vehicle requirements, but still met Ultra Low Emission Vehicle requirements. Research points to the catalyst temperature being a critical factor in meeting emission requirements. Initial engine emissions pass through with minimal conversion until the catalyst is heated to typical operating temperatures of 300–400°C. PHEVs also have trouble maintaining the minimum catalyst temperature throughout the entire test because the engine is turned off when the battery can support the load. It has been observed in both HEVs and PHEVs that the catalyst is intermittently unable to reduce nitrogen oxide emissions, which causes further emission releases. Research needs to be done to combat the initial emission spikes caused by a cold catalyst. Research also needs to be done to improve the reduction of nitrogen oxides by the catalyst system.

  4. Effect of a high or low ambient perinatal temperature on adult obesity in Osborne-Mendel and S5B/Pl rats.

    PubMed

    White, Christy L; Braymer, H Doug; York, David A; Bray, George A

    2005-05-01

    Perinatal environment is an important determinant of health status of adults. We tested the hypothesis that perinatal ambient temperature alters sympathetic activity and affects body composition in adult life and that this effect differs between S5B/Pl (S5B) and Osborne-Mendel (OM) strains of rat that were resistant (S5B) or susceptible (OM) to dietary obesity. From 1 wk before birth, rat litters were raised at either 18 or 30 degrees C until 2 mo of age while consuming a chow diet. Rats were then housed at normal housing temperature (22 degrees C) and provided either high-fat or low-fat diet. OM rats initially reared at 18 degrees C gained more weight on both diets than those reared at 30 degrees C. Perinatal temperature had no effect on body weight gain of the S5B rats on either diet. At 12 wk of age, OM and S5B rats reared at 18 degrees C had higher intakes of the high-fat diet than those reared at 30 degrees C but lower beta3-adrenergic receptor (beta3-AR) and uncoupling protein-1 (UCP1) mRNA levels in brown adipose tissue (BAT). The increase in metabolic rate in response to the beta3-agonist CL-316243, was greater in both OM and S5B rats reared at 18 degrees C than in those reared at 30 degrees C. Perinatal temperature differentially affects body weight in OM and S5B rats while having similar effects on food intake, response to a beta3-agonist, and BAT beta3-AR and UCP-1. The data suggest that OM rats are more susceptible to epigenetic programming than S5B rats.

  5. Feasibility of Using Full Synthetic Low Viscosity Engine Oil at High Ambient Temperatures in U.S. Army Engines

    DTIC Science & Technology

    2011-06-01

    Average Std. Dev. Average Std. Dev. Engine Speed RPM 3200 1.1 900 5.4 Torque ft*lb 283.6 4.7 3.4 0.8 Fuel Flow lb/hr 75.7 0.9 3.9 0.1 Power bhp 172.8...2.9 0.6 0.1 BSFC lb/ bhp *hr 0.438 0.005 6.879 1.664 Temperatures: Coolant In °F 192.0 0.8 93.6 1.1 Coolant Out °F 205.9 0.7 99.8 0.9 Oil Sump °F 263.0...Average Std. Dev. Average Std. Dev. Engine Speed RPM 2400.0 1.0 750.2 6.2 Torque* ft*lb 618.0 21.7 4.3 10.1 Fuel Flow lb/hr 101.0 10.5 2.8 0.8 Power* bhp

  6. Water Power Calculator Temperature and Analog Input/Output Module Ambient Temperature Testing

    SciTech Connect

    Mark D. McKay

    2011-02-01

    Water Power Calculator Temperature and Analog input/output Module Ambient Temperature Testing A series of three ambient temperature tests were conducted for the Water Power Calculator development using the INL Calibration Laboratory’s Tenney Environmental Chamber. The ambient temperature test results demonstrate that the Moore Industries Temperature Input Modules, Analog Input Module and Analog Output Module, ambient temperature response meet or exceed the manufactures specifications

  7. Preparation and characterization of mesoporous TiO2-sphere-supported Au-nanoparticle catalysts with high activity for CO oxidation at ambient temperature

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Huang, Shouying; Zhu, Baolin; Zhang, Shoumin; Huang, Weiping

    2016-11-01

    Mesoporous TiO2-sphere-supported Au-nanoparticles (Au/m-TiO2-spheres) catalysts have been synthesized by a simple method using tetrabutyl titanate as TiO2 precursor and characterized with XRD, BET, ICP, SEM, TEM, UV-Vis DRS, XPS, as well as FT-IR. The samples with the size in the range of 200-400 nm were almost perfectly spherical. The average diameter of pores was about 3.6 nm, and the mesopore size distribution was in the range of 2-6 nm with a narrow distribution. When the catalyst was calcined at 300 °C, the Au NPs with the size ca. 5 nm were highly dispersed on the surfaces of m-TiO2 spheres and partially embedded in the supports. Remarkably, the specific surface area of the Au/m-TiO2-spheres was as high as 117 m2 g-1. The CO-adsorbed catalyst showed an apparent IR adsorption peak at 1714 cm-1 that matched with bridging model CO. It means the catalysts should be of high catalytic activity for the CO oxidation due to they could adsorb and activate CO commendably. When Au-content was 0.48 wt.%, the Au/m-TiO2-spheres could convert CO completely into CO2 at ambient temperature.

  8. Ambient temperature cadmium zinc telluride radiation detector and amplifier circuit

    DOEpatents

    McQuaid, J.H.; Lavietes, A.D.

    1998-05-26

    A low noise, low power consumption, compact, ambient temperature signal amplifier for a Cadmium Zinc Telluride (CZT) radiation detector is disclosed. The amplifier can be used within a larger system (e.g., including a multi-channel analyzer) to allow isotopic analysis of radionuclides in the field. In one embodiment, the circuit stages of the low power, low noise amplifier are constructed using integrated circuit (IC) amplifiers , rather than discrete components, and include a very low noise, high gain, high bandwidth dual part preamplification stage, an amplification stage, and an filter stage. The low noise, low power consumption, compact, ambient temperature amplifier enables the CZT detector to achieve both the efficiency required to determine the presence of radionuclides and the resolution necessary to perform isotopic analysis to perform nuclear material identification. The present low noise, low power, compact, ambient temperature amplifier enables a CZT detector to achieve resolution of less than 3% full width at half maximum at 122 keV for a Cobalt-57 isotope source. By using IC circuits and using only a single 12 volt supply and ground, the novel amplifier provides significant power savings and is well suited for prolonged portable in-field use and does not require heavy, bulky power supply components. 9 figs.

  9. Ambient temperature cadmium zinc telluride radiation detector and amplifier circuit

    DOEpatents

    McQuaid, James H.; Lavietes, Anthony D.

    1998-05-29

    A low noise, low power consumption, compact, ambient temperature signal amplifier for a Cadmium Zinc Telluride (CZT) radiation detector. The amplifier can be used within a larger system (e.g., including a multi-channel analyzer) to allow isotopic analysis of radionuclides in the field. In one embodiment, the circuit stages of the low power, low noise amplifier are constructed using integrated circuit (IC) amplifiers , rather than discrete components, and include a very low noise, high gain, high bandwidth dual part preamplification stage, an amplification stage, and an filter stage. The low noise, low power consumption, compact, ambient temperature amplifier enables the CZT detector to achieve both the efficiency required to determine the presence of radio nuclides and the resolution necessary to perform isotopic analysis to perform nuclear material identification. The present low noise, low power, compact, ambient temperature amplifier enables a CZT detector to achieve resolution of less than 3% full width at half maximum at 122 keV for a Cobalt-57 isotope source. By using IC circuits and using only a single 12 volt supply and ground, the novel amplifier provides significant power savings and is well suited for prolonged portable in-field use and does not require heavy, bulky power supply components.

  10. Development of ambient temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Subbarao, S.; Shen, D. H.; Dawson, S.; Deligiannis, F.; Taraszkiewicz, J.; Halpert, Gerald

    1987-01-01

    JPL is developing ambient temperature secondary lithium cells for future spacecraft applications. Prior studies on experimental laboratory type Li-TiS2 cells yielded promising results in terms of cycle life and rate capability. To further assess the performance of this cell, 5 Ah engineering model cells were developed. Initially baseline cells were designed and fabricated. Each cell had 15 cathodes and 16 anodes and the ratio of anode to cathode capacity is 6:1. A solution of 1.5 molar LiAsF6 in 2Me-THF was used as the electrolyte. Cells were evaluated for their cycle life at C/1 and C/5 discharge rates and 100 percent depth of discharge. The cells were cycled between voltage limits 1.7 and 2.8 volts. The rate of charge in all cases is C/10. The results obtained indicate that cells can operate at C/10 to C/2 discharge rates and have an initial energy density of 70 Wh/kg. Cells delivered more than 100 cycles at C/2 discharge rate. The details of cell design, the test program, and the results obtained are described.

  11. Chondrules of the Very First Generation in Bencubbin/CH-like Meteorites QUE94411 and Hammadah Al Hamra 237: Condensation Origin at High Ambient Nebular Temperatures

    NASA Technical Reports Server (NTRS)

    Krot, Alexander N.; Meibom, Anders; Russell, Sara S.; Young, Edward; Alexander, Conel M.; McKeegan, Kevin D.; Lofgren, Gary; Cuzzi, Jeff; Zipfel, Jutta; Keil, Klaus

    2000-01-01

    Chondrules in QUE94411 and HH 237 formed at high ambient T prior to condensation of Fe,Ni-metal following a large scale thermal event that resulted in complete vaporization of a solar nebula region. These chondrules escaped subsequent remelting.

  12. Polymeric electrolytes for ambient temperature lithium batteries

    SciTech Connect

    Farrington, G.C. . Dept. of Materials Science and Engineering)

    1991-07-01

    A new type of highly conductive Li{sup +} polymer electrolyte, referred to as the Innovision polymer electrolyte, is completely amorphous at room temperature and has an ionic conductivity in the range of 10{sup {minus}3} S/cm. This report discusses the electrochemical characteristics (lithium oxidation and reduction), conductivity, and physical properties of Innovision electrolytes containing various dissolved salts. These electrolytes are particularly interesting since they appear to have some of the highest room-temperature lithium ion conductivities yet observed among polymer electrolytes. 13 refs. 11 figs., 2 tabs.

  13. Promoted Metals Combustion at Ambient and Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen D.; Davis, S. Eddie

    2005-01-01

    Promoted combustion testing of materials, Test 17 of NASA STD-6001, has been used to assess metal propensity to burn in oxygen rich environments. An igniter is used at the bottom end of a rod to promote ignition, and if combustion is sustained, the burning progresses from the bottom to the top of the rod. The physical mechanisms are very similar to the upward flammability test, Test 1 of NASA STD-6001. The differences are in the normal environmental range of pressures, oxygen content, and sample geometry. Upward flammability testing of organic materials can exhibit a significant transitional region between no burning to complete quasi-state burning. In this transitional region, the burn process exhibits a probabilistic nature. This transitional region has been identified for metals using the promoted combustion testing method at ambient initial temperatures. The work given here is focused on examining the transitional region and the quasi-steady burning region both at conventional ambient testing conditions and at elevated temperatures. A new heated promoted combustion facility and equipment at Marshall Space Flight Center have just been completed to provide the basic data regarding the metals operating temperature limits in contact with oxygen rich atmospheres at high pressures. Initial data have been obtained for Stainless Steel 304L, Stainless Steel 321, Haynes 214, and Inconel 718 at elevated temperatures in 100-percent oxygen atmospheres. These data along with an extended data set at ambient initial temperature test conditions are examined. The pressure boundaries of acceptable, non-burning usage is found to be lowered at elevated temperature.

  14. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

    PubMed

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  15. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation

    NASA Astrophysics Data System (ADS)

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  16. Developing a thermoacoustic sensor adaptive to ambient temperatures.

    PubMed

    Xing, Jida; Ang, Woon; Lim, Allan; Yu, Xiaojian; Chen, Jie

    2013-01-01

    In this paper, a simple and adaptive thermoacoustic sensor was designed to measure Low Intensity Pulsed Ultrasound (LIPUS). Compared to other thermoacoustic sensor designs, our novelty lies in (i) integrating an ultrasound medium layer during the measurement to simplify the complicated set-up procedures and (ii) taking the effect of ambient temperatures into design consideration. After measuring temperature increases with various ambient temperatures under different ultrasound intensities, a relationship among ultrasound intensities, ambient temperatures and coefficients of temporal temperature changes was calculated. Our improved design has made the sensor easy to operate and its performance more accurate and consistent than the thermoacoustic sensor designs without considering ambient temperatures. In all, our improved design greatly enhances the thermoacoustic sensor in practical ultrasound calibration.

  17. Quantitative methods for stochastic high frequency spatio-temporal and non-linear analysis: Assessing health effects of exposure to extreme ambient temperature

    NASA Astrophysics Data System (ADS)

    Liss, Alexander

    regionalization method algorithmically forms eight climatically homogeneous regions for Conterminous US from satellite Remote Sensing inputs. The relative risk of hospitalizations due to extreme ambient temperature varied across climatic regions. Difference in regional hospitalization rates suggests presence of an adaptation effect to a prevailing climate. In various climatic regions the hospitalizations peaked earlier than the peak of exposure. This suggests disproportionally high impact of extreme weather events, such as cold spells or heat waves when they occur early in the season. These findings provide an insight into the use of high frequency disjoint data sets for the assessment of the magnitude, timing, synchronization and non-linear properties of adverse health consequences due to exposure to extreme weather events to the elderly in defined climatic regions. These findings assist in the creation of decision support frameworks targeting preventions and adaptation strategies such as improving infrastructure, providing energy assistance, education and early warning notifications for the vulnerable population. This dissertation offers a number of methodological innovations for the assessment of the high frequency spatio-temporal and non-linear impacts of extreme weather events on human health. These innovations help to ensure an improved protection of the elderly population, aid policy makers in the development of efficient disaster prevention strategies, and facilitate more efficient allocation of scarce resources.

  18. High-temperature superconducting radiofrequency probe for magnetic resonance imaging applications operated below ambient pressure in a simple liquid-nitrogen cryostat

    NASA Astrophysics Data System (ADS)

    Lambert, Simon; Ginefri, Jean-Christophe; Poirier-Quinot, Marie; Darrasse, Luc

    2013-05-01

    The present work investigates the joined effects of temperature and static magnetic field on the electrical properties of a 64 MHz planar high-temperature superconducting (HTS) coil, in order to enhance the signal-to-noise ratio (SNR) in nuclear magnetic resonance (NMR) applications with a moderate decrease of the HTS coil temperature (THTS). Temperature control is provided with accuracy better than 0.1 K from 80 to 66 K by regulating the pressure of the liquid nitrogen bath of a dedicated cryostat. The actual temperature of the HTS coil is obtained using a straightforward wireless method that eliminates the risks of coupling electromagnetic interference to the HTS coil and of disturbing the static magnetic field by DC currents near the region of interest. The resonance frequency ( f0) and the quality factor (Q) of the HTS coil are measured as a function of temperature in the 0-4.7 T field range with parallel and orthogonal orientations relative to the coil plane. The intrinsic HTS coil sensitivity and the detuning effect are then analyzed from the Q and f0 data. In the presence of the static magnetic field, the initial value of f0 in Earth's field could be entirely recovered by decreasing THTS, except for the orthogonal orientation above 1 T. The improvement of Q by lowering THTS was substantial. From 80 to 66 K, Q was multiplied by a factor of 6 at 1.5 T in orthogonal orientation. In parallel orientation, the maximum measured improvement of Q from 80 K to 66 K was a factor of 2. From 80 to 66 K, the improvement of the RF sensitivity relative to the initial value at the Earth's field and ambient pressure was up to 4.4 dB in parallel orientation. It was even more important in orthogonal orientation and continued to increase, up to 8.4 dB, at the maximum explored field of 1.5 T. Assuming that the noise contributions from the RF receiver are negligible, the SNR improvement using enhanced HTS coil cooling in NMR experiments was extracted from Q measurements either

  19. A method to measure internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures

    NASA Astrophysics Data System (ADS)

    Tian, Qijie; Chang, Songtao; Li, Zhou; He, Fengyun; Qiao, Yanfeng

    2017-03-01

    The suppression level of internal stray radiation is a key criterion for infrared imaging systems, especially for high-precision cryogenic infrared imaging systems. To achieve accurate measurement for internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures, a measurement method, which is based on radiometric calibration, is presented in this paper. First of all, the calibration formula is deduced considering the integration time, and the effect of ambient temperature on internal stray radiation is further analyzed in detail. Then, an approach is proposed to measure the internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures. By calibrating the system under two ambient temperatures, the quantitative relation between the internal stray radiation and the ambient temperature can be acquired, and then the internal stray radiation of the cryogenic infrared imaging system under various ambient temperatures can be calculated. Finally, several experiments are performed in a chamber with controllable inside temperatures to evaluate the effectiveness of the proposed method. Experimental results indicate that the proposed method can be used to measure internal stray radiation with high accuracy at various ambient temperatures and integration times. The proposed method has some advantages, such as simple implementation and the capability of high-precision measurement. The measurement results can be used to guide the stray radiation suppression and to test whether the internal stray radiation suppression performance meets the requirement or not.

  20. High Temperature, High Ambient CO2 Affect the Interactions between Three Positive-Sense RNA Viruses and a Compatible Host Differentially, but not Their Silencing Suppression Efficiencies

    PubMed Central

    Del Toro, Francisco J.; Aguilar, Emmanuel; Hernández-Walias, Francisco J.; Tenllado, Francisco; Chung, Bong-Nam; Canto, Tomas

    2015-01-01

    We compared infection of Nicotiana benthamiana plants by the positive-sense RNA viruses Cucumber mosaic virus (CMV), Potato virus Y (PVY), and by a Potato virus X (PVX) vector, the latter either unaltered or expressing the CMV 2b protein or the PVY HCPro suppressors of silencing, at 25°C vs. 30°C, or at standard (~401 parts per million, ppm) vs. elevated (970 ppm) CO2 levels. We also assessed the activities of their suppressors of silencing under those conditions. We found that at 30°C, accumulation of the CMV isolate and infection symptoms remained comparable to those at 25°C, whereas accumulation of the PVY isolate and those of the three PVX constructs decreased markedly, even when expressing the heterologous suppressors 2b or HCPro, and plants had either very attenuated or no symptoms. Under elevated CO2 plants grew larger, but contained less total protein/unit of leaf area. In contrast to temperature, infection symptoms remained unaltered for the five viruses at elevated CO2 levels, but viral titers in leaf disks as a proportion of the total protein content increased in all cases, markedly for CMV, and less so for PVY and the PVX constructs. Despite these differences, we found that neither high temperature nor elevated CO2 prevented efficient suppression of silencing by their viral suppressors in agropatch assays. Our results suggest that the strength of antiviral silencing at high temperature or CO2 levels, or those of the viral suppressors that counteract it, may not be the main determinants of the observed infection outcomes. PMID:26313753

  1. High Temperature, High Ambient CO₂ Affect the Interactions between Three Positive-Sense RNA Viruses and a Compatible Host Differentially, but not Their Silencing Suppression Efficiencies.

    PubMed

    Del Toro, Francisco J; Aguilar, Emmanuel; Hernández-Walias, Francisco J; Tenllado, Francisco; Chung, Bong-Nam; Canto, Tomas

    2015-01-01

    We compared infection of Nicotiana benthamiana plants by the positive-sense RNA viruses Cucumber mosaic virus (CMV), Potato virus Y (PVY), and by a Potato virus X (PVX) vector, the latter either unaltered or expressing the CMV 2b protein or the PVY HCPro suppressors of silencing, at 25°C vs. 30°C, or at standard (~401 parts per million, ppm) vs. elevated (970 ppm) CO2 levels. We also assessed the activities of their suppressors of silencing under those conditions. We found that at 30°C, accumulation of the CMV isolate and infection symptoms remained comparable to those at 25°C, whereas accumulation of the PVY isolate and those of the three PVX constructs decreased markedly, even when expressing the heterologous suppressors 2b or HCPro, and plants had either very attenuated or no symptoms. Under elevated CO2 plants grew larger, but contained less total protein/unit of leaf area. In contrast to temperature, infection symptoms remained unaltered for the five viruses at elevated CO2 levels, but viral titers in leaf disks as a proportion of the total protein content increased in all cases, markedly for CMV, and less so for PVY and the PVX constructs. Despite these differences, we found that neither high temperature nor elevated CO2 prevented efficient suppression of silencing by their viral suppressors in agropatch assays. Our results suggest that the strength of antiviral silencing at high temperature or CO2 levels, or those of the viral suppressors that counteract it, may not be the main determinants of the observed infection outcomes.

  2. Ambient Temperature and Morbidity: A Review of Epidemiological Evidence

    PubMed Central

    Ye, Xiaofang; Wolff, Rodney; Yu, Weiwei; Vaneckova, Pavla; Pan, Xiaochuan

    2011-01-01

    Objective: In this paper, we review the epidemiological evidence on the relationship between ambient temperature and morbidity. We assessed the methodological issues in previous studies and proposed future research directions. Data sources and data extraction: We searched the PubMed database for epidemiological studies on ambient temperature and morbidity of noncommunicable diseases published in refereed English journals before 30 June 2010. Forty relevant studies were identified. Of these, 24 examined the relationship between ambient temperature and morbidity, 15 investigated the short-term effects of heat wave on morbidity, and 1 assessed both temperature and heat wave effects. Data synthesis: Descriptive and time-series studies were the two main research designs used to investigate the temperature–morbidity relationship. Measurements of temperature exposure and health outcomes used in these studies differed widely. The majority of studies reported a significant relationship between ambient temperature and total or cause-specific morbidities. However, there were some inconsistencies in the direction and magnitude of nonlinear lag effects. The lag effect of hot temperature on morbidity was shorter (several days) compared with that of cold temperature (up to a few weeks). The temperature–morbidity relationship may be confounded or modified by sociodemographic factors and air pollution. Conclusions: There is a significant short-term effect of ambient temperature on total and cause-specific morbidities. However, further research is needed to determine an appropriate temperature measure, consider a diverse range of morbidities, and to use consistent methodology to make different studies more comparable. PMID:21824855

  3. Ambient pressure, low-temperature synthesis and characterization of colloidal InN nanocrystals

    PubMed Central

    Hsieh, Jennifer C.; Yun, Dong Soo; Hu, Evelyn

    2014-01-01

    Highly soluble, non-aggregated colloidal wurtzite InN nanocrystals were obtained through an ambient pressure, low-temperature method followed by post-synthesis treatment with nitric acid. PMID:25484524

  4. Effects of dietary supplementation of selenium-enriched probiotics on production performance and intestinal microbiota of weanling piglets raised under high ambient temperature.

    PubMed

    Lv, C H; Wang, T; Regmi, N; Chen, X; Huang, K; Liao, S F

    2015-12-01

    This study was designed to evaluate the efficacy of selenium-enriched probiotics (SeP) on production performance and intestinal microbiota of piglets raised under high ambient temperature. Forty-eight cross-bred weanling piglets (28 days old), randomly allotted into 12 pens (four piglets/pen) and four dietary treatments (three pens/treatment group), were fed ad libitum for 42 days a basal diet (Con) or the basal diet supplemented with probiotics (Pro), sodium selenite (ISe) or a SeP preparation. Blood and faecal samples were collected on days 0, 14, 28 and 42 post-treatment. The SeP group had higher final BW (p < 0.05), greater ADG (p < 0.05) and lower FCR (p < 0.01) than the Pro, ISe or Con group. The diarrhoea incidence rate of either SeP or Pro group was lower (p < 0.01) than the ISe or Con group. Blood Se concentration and GSH-Px activity were both higher (p < 0.01) in the SeP than in the Pro, ISe or Con group. On days 28 and 42, the serum concentrations of T3 were higher (p < 0.01) and T4 lower (p < 0.01) in the SeP than in the ISe group, and the T3 and T4 concentrations in the ISe group, in turn, were higher (p < 0.05) and lower (p < 0.01), respectively, than in the Pro or Con group. Also on days 28 and 42, the faecal counts of lactobacillus bacteria were higher (p < 0.01) while Escherichia coli lower (p < 0.01) in the SeP or Pro group as compared to the ISe or Con group. The results of RFLP showed that the faecal microbial flora in the SeP group changed the most (numerically) as compared to the Pro or ISe group. These results suggest that the SeP product may serve as a better alternative to antibiotics than the solo probiotics for using as a growth promoter for weanling piglets.

  5. Entrainment of circadian rhythm by ambient temperature cycles in mice.

    PubMed

    Refinetti, Roberto

    2010-08-01

    Much is known about how environmental light-dark cycles synchronize circadian rhythms in animals. The ability of environmental cycles of ambient temperature to synchronize circadian rhythms has also been investigated extensively but mostly in ectotherms. In the present study, the synchronization of the circadian rhythm of running-wheel activity by environmental cycles of ambient temperature was studied in laboratory mice. Although all mice were successfully entrained by a light-dark cycle, only 60% to 80% of the mice were entrained by temperature cycles (24-32 degrees C or 24-12 degrees C), and attainment of stable entrainment seemed to take longer under temperature cycles than under a light-dark cycle. This suggests that ambient temperature cycles are weaker zeitgebers than light-dark cycles, which is consistent with the results of the few previous studies using mammalian species. Whereas 80% of the mice were entrained by 24-h temperature cycles, only 60% were entrained by 23-h cycles, and none was entrained by 25-h cycles. The results did not clarify whether entrainment by temperature cycles is caused directly by temperature or indirectly through a temperature effect on locomotor activity, but it is clear that the rhythm of running-wheel activity in mice can be entrained by ambient temperature cycles in the nonnoxious range.

  6. Effect of high ambient temperature and naked neck genotype on performance of dwarf brown-egg layers selected for improved clutch length.

    PubMed

    Chen, C F; Bordas, A; Gourichon, D; Tixier-Boichard, M

    2004-06-01

    1. Two experimental lines of dwarf brown-egg layers selected on clutch length were reciprocally crossed. In total, 288 hens, from three genotypes: L1, purebred normally feathered (121 hens), F1, crossbred and heterozygous for the NA mutation (99 hens) or L2, purebred homozygous for NA (68 hens) were housed in three climatic rooms at 22 degrees C and three climatic rooms at 32 degrees C. 2. Body weight, daily egg production records, feed intake and some anatomical and physiological traits were recorded. Canonical discriminant analysis was used to examine the relationships among all measured traits and to compare the experimental groups as defined by genotype and temperature. 3. Heterosis effects were observed on body weight, feed intake, egg mass and some anatomical traits at 22 degrees C, but were negligible for most of the traits measured at 32 degrees C except for body weight at 34 weeks, clutch length and some anatomical traits. 4. Genotype by temperature interactions were observed for egg production, egg mass and feed intake. The temperature stress was severe, with a marked decrease in egg production. The naked neck gene could limit the negative effect of long-term heat stress. Egg weight was increased by the NA gene, as usually observed in layers. 5. The first three canonical variates explained altogether 97.4% of the variance. The first canonical variate was associated almost exclusively with ambient temperature. The second was associated with genotype. The third was associated with heterozygous genotype for NA mutation and genotype by temperature interaction. Stepwise discriminant analysis indicated that 12 traits out of 20 were effective at detecting the differences among the genotype and temperature combinations.

  7. Warmer ambient temperatures depress liver function in a mammalian herbivore

    PubMed Central

    Kurnath, Patrice; Dearing, M. Denise

    2013-01-01

    Diet selection in mammalian herbivores is thought to be mainly influenced by intrinsic factors such as nutrients and plant secondary compounds, yet extrinsic factors like ambient temperature may also play a role. In particular, warmer ambient temperatures could enhance the toxicity of plant defence compounds through decreased liver metabolism of herbivores. Temperature-dependent toxicity has been documented in pharmacology and agriculture science but not in wild mammalian herbivores. Here, we investigated how ambient temperature affects liver metabolism in the desert woodrat, Neotoma lepida. Woodrats (n = 21) were acclimated for 30 days to two ambient temperatures (cool = 21°C, warm = 29°C). In a second experiment, the temperature exposure was reduced to 3.5 h. After temperature treatments, animals were given a hypnotic agent and clearance time of the agent was estimated from the duration of the hypnotic state. The average clearance time of the agent in the long acclimation experiment was 45% longer for animals acclimated to 29°C compared with 21°C. Similarly, after the short exposure experiment, woodrats at 29°C had clearance times 26% longer compared with 21°C. Our results are consistent with the hypothesis that liver function is reduced at warmer environmental temperatures and may provide a physiological mechanism through which climate change affects herbivorous mammals. PMID:24046878

  8. Low ambient temperature and neuroendocrine response to hypoglycemia in men.

    PubMed

    Jezová, D; Juránková, E; Kvetnanský, R; Kaciuba-Uscilko, H; Nazar, K; Vigas, M

    1995-12-01

    Nutritional factors, such as an excess or a deficiency of glucose, play an important role in neuroendocrine regulations. Hormonal and metabolic responses to hypoglycemia were examined in healthy non-obese volunteers under conditions of low ambient temperature. Hypoglycemia was induced by intravenous injection of insulin in two randomized trials performed at room temperature and at 4 degrees C. At room temperature, the typical neuroendocrine response to hypoglycemia was established. The increases of ACTH, beta-endorphin, growth hormone and cortisol in response to insulin hypoglycemia failed to be modified by low ambient temperature. Acute cold exposure significantly reduced epinephrine and totally inhibited prolactin response to insulin-induced hypoglycemia. In spite of significant changes in epinephrine response to hypoglycemia at low ambient temperature, no striking differences in plasma glucose levels compared to those measured at room temperature were observed. However, under conditions of low temperature the reestablishment of normoglycemia was delayed. No changes in free fatty acids were found under our experimental conditions. The presented data show that low ambient temperature exerts selective effects on some neuroendocrine and metabolic parameters.

  9. Advanced Catalysts for the Ambient Temperature Oxidation of Carbon Monoxide and Formaldehyde

    NASA Technical Reports Server (NTRS)

    Nalette, Tim; Eldridge, Christopher; Yu, Ping; Alpetkin, Gokhan; Graf, John

    2010-01-01

    The primary applications for ambient temperature carbon monoxide (CO) oxidation catalysts include emergency breathing masks and confined volume life support systems, such as those employed on the Shuttle. While Hopcalite is typically used in emergency breathing masks for terrestrial applications, in the 1970s, NASA selected a 2% platinum (Pt) on carbon for use on the Shuttle since it is more active and also more tolerant to water vapor. In the last 10-15 years there have been significant advances in ambient temperature CO oxidation catalysts. Langley Research Center developed a monolithic catalyst for ambient temperature CO oxidation operating under stoichiometric conditions for closed loop carbon dioxide (CO2) laser applications which is also advertised as having the potential to oxidize formaldehyde (HCHO) at ambient temperatures. In the last decade it has been discovered that appropriate sized nano-particles of gold are highly active for CO oxidation, even at sub-ambient temperatures, and as a result there has been a wealth of data reported in the literature relating to ambient/low temperature CO oxidation. In the shorter term missions where CO concentrations are typically controlled via ambient temperature oxidation catalysts, formaldehyde is also a contaminant of concern, and requires specially treated carbons such as Calgon Formasorb as untreated activated carbon has effectively no HCHO capacity. This paper examines the activity of some of the newer ambient temperature CO and formaldehyde (HCHO) oxidation catalysts, and measures the performance of the catalysts relative to the NASA baseline Ambient Temperature Catalytic Oxidizer (ATCO) catalyst at conditions of interest for closed loop trace contaminant control systems.

  10. Passive radiative cooling below ambient air temperature under direct sunlight.

    PubMed

    Raman, Aaswath P; Anoma, Marc Abou; Zhu, Linxiao; Rephaeli, Eden; Fan, Shanhui

    2014-11-27

    Cooling is a significant end-use of energy globally and a major driver of peak electricity demand. Air conditioning, for example, accounts for nearly fifteen per cent of the primary energy used by buildings in the United States. A passive cooling strategy that cools without any electricity input could therefore have a significant impact on global energy consumption. To achieve cooling one needs to be able to reach and maintain a temperature below that of the ambient air. At night, passive cooling below ambient air temperature has been demonstrated using a technique known as radiative cooling, in which a device exposed to the sky is used to radiate heat to outer space through a transparency window in the atmosphere between 8 and 13 micrometres. Peak cooling demand, however, occurs during the daytime. Daytime radiative cooling to a temperature below ambient of a surface under direct sunlight has not been achieved because sky access during the day results in heating of the radiative cooler by the Sun. Here, we experimentally demonstrate radiative cooling to nearly 5 degrees Celsius below the ambient air temperature under direct sunlight. Using a thermal photonic approach, we introduce an integrated photonic solar reflector and thermal emitter consisting of seven layers of HfO2 and SiO2 that reflects 97 per cent of incident sunlight while emitting strongly and selectively in the atmospheric transparency window. When exposed to direct sunlight exceeding 850 watts per square metre on a rooftop, the photonic radiative cooler cools to 4.9 degrees Celsius below ambient air temperature, and has a cooling power of 40.1 watts per square metre at ambient air temperature. These results demonstrate that a tailored, photonic approach can fundamentally enable new technological possibilities for energy efficiency. Further, the cold darkness of the Universe can be used as a renewable thermodynamic resource, even during the hottest hours of the day.

  11. Ambient temperature influences birds' decisions to eat toxic prey☆

    PubMed Central

    Chatelain, M.; Halpin, C.G.; Rowe, C.

    2013-01-01

    Aposematic prey warn predators of their toxicity using conspicuous signals. However, predators regularly include aposematic prey in their diets, particularly when they are in a poor energetic state and in need of nutrients. We investigated whether or not an environmental factor, ambient temperature, could change the energetic state of predators and lead to an increased intake of prey that they know to contain toxins. We found that European starlings, Sturnus vulgaris, increased their consumption of mealworm, Tenebrio molitor, prey containing quinine (a mild toxin) when the ambient temperature was reduced below their thermoneutral zone from 20 °C to 6 °C. The birds differed in their sensitivity to changes in ambient temperature, with heavier birds increasing the number of toxic prey they ate more rapidly with decreasing temperature compared to birds with lower body mass. This could have been the result of their requiring more nutrients at lower temperatures or being better able to detoxify quinine. Taken together, our results suggest that conspicuous coloration may be more costly at lower temperatures, and that aposematic prey may need to invest more in chemical defences as temperatures decline. Our study also provides novel insights into what factors affect birds' decisions to eat toxic prey, and demonstrates that selection pressures acting on prey defences can vary with changing temperature across days, seasons, climes, and potentially in response to climate change. PMID:24109148

  12. Studies in Ambient Temperature Ionic Liquids.

    DTIC Science & Technology

    1987-06-30

    observed. High stability of triiodide ion in neutral butylpyridinium tetracnloroaluminate indicates relatively weak intermolecular interactions in...tetraethylammonium triiodide solutions a mixture of IC12-, I2CI-, I3 - and I- forms. The formation constants of IgC- and 13 - and the equilibrium...constant of IZCI- disproportionation are estimated. ABSTRACT e Iodine, iodine Chloride. tetreethylammonium Iodide, and tetraethylammonium triiodide

  13. Effects of the ambient temperature on the airflow across a Caucasian nasal cavity.

    PubMed

    Burgos, M A; Sanmiguel-Rojas, E; Martín-Alcántara, A; Hidalgo-Martínez, M

    2014-03-01

    We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.

  14. Antioxidant enzyme activities, plasma hormone levels and serum metabolites of finishing broiler chickens reared under high ambient temperature and fed lemon and orange peel extracts and Curcuma xanthorrhiza essential oil.

    PubMed

    Akbarian, A; Golian, A; Kermanshahi, H; De Smet, S; Michiels, J

    2015-02-01

    The negative effects of high ambient temperature during some months of the year on poultry production have been of great concern in many countries. Dietary modifications are among the most practical ways to alleviate the effects of high temperature. Possible effects of dietary supplementation with 200 or 400 mg/kg feed of lemon peel extract (LPE), orange peel extract (OPE) and Curcuma xanthorrhiza essential oil (CXEO) under hot conditions (34 °C with 50% relative humidity for 5 h daily starting from day 28 until day 38 of age) on blood antioxidant enzyme activities, biochemical parameters and antibody titres of broiler chickens were investigated. All extracts are rich in phenolic compounds and highly available. Compared to control, supplementation with OPE at 400 mg/kg and CXEO significantly increased erythrocyte glutathione peroxidase and superoxide dismutase activity, plasma growth hormone concentrations and serum phosphorus, total protein and chloride concentrations and decreased serum low-density lipoprotein and cholesterol concentrations in chickens at 38 days of age. Regarding antibody titres, CXEO supplementation at 400 mg/kg caused a significant increase in bronchitis antibody titres. Supplementation with LPE and OPE gave more inconsistent results. Most interesting, 400 mg/kg LPE significantly increased 3,5,3'-triiodothyronine and GH concentration as compared to the control. In conclusion, the herbal extracts tested in this study, in particular CXEO at 400 mg/kg, may relieve some of the changes in blood composition induced by increased ambient temperatures.

  15. High Temperature Capacitor Development

    SciTech Connect

    John Kosek

    2009-06-30

    unique high-temperature electrolyte developed during the course of the program. During this program the feasibility of operating a high voltage hybridized capacitor at 230oC was demonstrated. Capacitor specifications were established in conjunction with potential capacitor users. A method to allow for capacitor operation at both ambient and elevated temperatures was demonstrated. The program was terminated prior to moving into Phase II due to a lack of cost-sharing funds.

  16. The dependence of surface temperature on IGBTs load and ambient temperature

    NASA Astrophysics Data System (ADS)

    Alexander, Čaja; Marek, Patsch

    2015-05-01

    Currently, older power electronics and electrotechnics are improvement and at the same time developing new and more efficient devices. These devices produce in their activities a significant part of the heat which, if not effectively drained, causing damage to these elements. In this case, it is important to develop new and more efficient cooling system. The most widespread of modern methods of cooling is the cooling by heat pipe. This contribution is aimed at cooling the insulated-gate bipolar transistor (IGBT) elements by loop heat pipe (LHP). IGBTs are very prone to damage due to high temperatures, and therefore is the important that the surface temperature was below 100°C. It was therefore created a model that examined what impact of surface temperature on the IGBT element and heat removal at different load and constant ambient temperature.

  17. Low Ambient Temperature and Intracerebral Hemorrhage: The INTERACT2 Study

    PubMed Central

    Zheng, Danni; Arima, Hisatomi; Sato, Shoichiro; Gasparrini, Antonio; Heeley, Emma; Delcourt, Candice; Lo, Serigne; Huang, Yining; Wang, Jiguang; Stapf, Christian; Robinson, Thompson; Lavados, Pablo; Chalmers, John; Anderson, Craig S.

    2016-01-01

    Background Rates of acute intracerebral hemorrhage (ICH) increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2) participants on an hourly timescale. Methods INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH (<6h of onset) and elevated systolic blood pressure (SBP, 150–220 mmHg) assigned to intensive (target SBP <140 mmHg) or guideline-recommended (SBP <180 mmHg) BP treatment. We linked individual level hourly temperature to baseline data of 1997 participants, and performed case-crossover analyses using a distributed lag non-linear model with 24h lag period to assess the association of ambient temperature and risk of ICH. Results were presented as overall cumulative odds ratios (ORs) and 95% CI. Results Low ambient temperature (≤10°C) was associated with increased risks of ICH: overall cumulative OR was 1.37 (0.99–1.91) for 10°C, 1.92 (1.31–2.81) for 0°C, 3.13 (1.89–5.19) for -10°C, and 5.76 (2.30–14.42) for -20°C, as compared with a reference temperature of 20°C.There was no clear relation of low temperature beyond three hours after exposure. Results were consistent in sensitivity analyses. Conclusions Exposure to low ambient temperature within several hours increases the risk of ICH. Trial Registration ClinicalTrials.gov NCT00716079 PMID:26859491

  18. Ambient temperature and activation of implantable cardioverter defibrillators

    NASA Astrophysics Data System (ADS)

    McGuinn, L.; Hajat, S.; Wilkinson, P.; Armstrong, B.; Anderson, H. R.; Monk, V.; Harrison, R.

    2013-09-01

    The degree to which weather influences the occurrence of serious cardiac arrhythmias is not fully understood. To investigate, we studied the timing of activation of implanted cardiac defibrillators (ICDs) in relation to daily outdoor temperatures using a fixed stratum case-crossover approach. All patients attending ICD clinics in London between 1995 and 2003 were recruited onto the study. Temperature exposure for each ICD patient was determined by linking each patient's postcode of residence to their nearest temperature monitoring station in London and the South of England. There were 5,038 activations during the study period. Graphical inspection of ICD activation against temperature suggested increased risk at lower but not higher temperatures. For every 1 °C decrease in ambient temperature, risk of ventricular arrhythmias up to 7 days later increased by 1.2 % (95 % CI -0.6 %, 2.9 %). In threshold models, risk of ventricular arrhythmias increased by 11.2 % (0.5 %, 23.1 %) for every 1° decrease in temperature below 2 °C. Patients over the age of 65 exhibited the highest risk. This large study suggests an inverse relationship between ambient outdoor temperature and risk of ventricular arrhythmias. The highest risk was found for patients over the age of 65. This provides evidence about a mechanism for some cases of low-temperature cardiac death, and suggests a possible strategy for reducing risk among selected cardiac patients by encouraging behaviour modification to minimise cold exposure.

  19. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  20. Incubation Temperature during Fetal Development Influences Morphophysiological Characteristics and Preferred Ambient Temperature of Chicken Hatchlings

    PubMed Central

    Morita, Viviane de Souza; de Almeida, Vitor Rosa; Matos, João Batista; Vicentini, Tamiris Iara; van den Brand, Henry; Boleli, Isabel Cristina

    2016-01-01

    Skin and feather characteristics, which play a critical role in body temperature maintenance, can be affected by incubation circumstances, such as incubation temperature. However, no study to date has assessed the influence of incubation temperature during the fetal stage on morphometric characteristics and vascular development of the skin, feather characteristics, and their relationship to hormone levels and preferred temperature in later life in chickens. Broiler breeder eggs were exposed to low (36°C), control (37.5°C), or high (39°C) temperatures (treatments LT, CK, and HT, respectively) from day 13 of incubation onward, because it is known that the endocrine axes are already established at this time. During this period, eggshell temperature of HT eggs (38.8±0.33°C) was higher than of LT (37.4±0.08°C) and CK eggs (37.8 ±0.15°C). The difference between eggshell and incubator air temperature diminished with the increasing incubation temperature, and was approximately zero for HT. HT hatchlings had higher surface temperature on the head, neck, and back, and thinner and more vascularized skin than did CK and LT hatchlings. No differences were found among treatments for body weight, total feather weight, number and length of barbs, barbule length, and plasma T4 concentration. LT hatchlings showed lower plasma T3 and GH, as well as lower T3/T4 ratio and decreased vascularity in the neck, back, and thigh skin compared to CK hatchlings. On the other hand, HT hatchlings had decreased skin thickness and increased vascularity, and preferred a higher ambient temperature compared to CK and HT hatchlings. In addition, for all treatments, surface temperature on the head was higher than of the other body regions. We conclude that changes in skin thickness and vascularity, as well as changes in thyroid and growth hormone levels, are the result of embryonic strategies to cope with higher or lower than normal incubation temperatures. Additionally exposure to increased

  1. Composition for producing polyurethane resin at ambient temperature

    SciTech Connect

    Kamatani, Y.; Nishino, K.; Tanaka, M.; Yamazaki, K.

    1984-06-26

    Disclosed is a composition for polyurethane resins which is ordinarily of two-package type and curable at ambient temperature and which comprises an isocyanate component having oxadiazinetrione ring as a curing agent and a polyol component, having in the molecule, at least one of a tertiary amino group, a quaternary ammonium group and a salt-formed carboxyl group as a main component. The composition has excellent curability and provides cured products excellent in adhesiveness and physical properties.

  2. [Research on Raman spectra of isooctane at ambient temperature and ambient pressure to 1. 2 GPa].

    PubMed

    Zhang, Fei-fei; Zheng, Hai-fei

    2012-03-01

    The experimental study of the Raman spectral character for liquid isooctane (2,2,4-trimethylpentane, ATM) was con ducted by moissanite anvil cell at the pressure of 0-1.2 GPa and the ambient temperature. The results show that the Raman peaks of the C-H stretching vibration shift to higher frenquencies with increasing pressures. The relations between the system pressure and peaks positions is given as following: v2 873 = 0.002 8P+2 873.3; v2 905 = 0.004 8P+2 905.4; v2 935 = 0.002 7P+ 2 935.0; v2 960 = 0.012P+2 960.9. The Raman spectra of isooctane abruptly changed at the pressure about 1.0 GPa and the liquid-solid phase transition was observed by microscope. With the freezing pressure at ambient temperature and the melting temperature available at 1 atm, the authors got the liquid-solid phase diagram of isooctane. According to Clapeyron equation, the authors obtained the differences of volume and entropy for the liquid-solid phase transition of isooctane: deltaV(m) = 4.46 x 10(-6) m3 x mol-1 and deltaS = -30.32 J x K(-1) x mol(-1).

  3. Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

    SciTech Connect

    Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel

    2009-02-27

    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.

  4. Correlation between structure and fluidity of coal tar pitch fractions studied by ambient {sup 13}C and high temperature in-situ {sup 1}H nuclear magnetic resonance

    SciTech Connect

    Andresen, J.M.; Schober, H.H.; Rusinko, F.J. Jr.

    1999-07-01

    The unique properties of coal tar pitches have resulted in numerous applications for carbon products, such as binders for carbon artifacts. However, as the number of by-product coke ovens is diminishing, the design of superior binders from alternative materials or processes is sought by the carbon industry. Accordingly, structural characterization of coal tar pitches and their solvent fractions, using quantitative analytical techniques is required to successfully obtain this goal. Quantitative solid state {sup 13}C NMR has previously been shown to be a powerful technique to study the overall aromatic ring-size for coal tar pitches and their toluene insoluble (TI) fractions. The TI fraction can further be separated into its quinoline soluble part (beta-resin) and insoluble fraction (QI). Both these fractions affect the overall coking yield and especially the fluidity of the pitches. The assessment of fluidity interactions between coal tar pitch solvent fractions during heating is therefore important for the future design of pitches from untraditional sources or processes. High temperature {sup 1}H NMR is a useful technique to investigate the fluid and rigid components of pitches, especially with its interaction with coal and to quantify mesophase. However, very little work has been performed to correlate the overall fluidity behavior of pitch with the mobility of its different solubility fractions and their structure. Accordingly, this paper addresses the fluidity interactions between different pitch solvent fractions (TS, beta-resin and QI) by high temperature {sup 1}H NMR. Particularly, the fluidity studies on the beta-resin alone can verify whether this fraction becomes plastic during heating.

  5. Effect of ambient temperature on evaporative water loss in the subterranean rodent Ctenomys talarum.

    PubMed

    Baldo, María Belén; Antenucci, C Daniel; Luna, Facundo

    2015-10-01

    Subterranean rodents face unique thermoregulatory challenges. Evaporative water loss (EWL) is a crucial mechanism for maintaining heat balance in endotherms subjected to heat stress but also leads to potential dehydration. EWL depends on gradients of temperature and humidity between the surface of the individual and the surrounding environment. Underground burrows generally provide a stable water vapor saturated atmosphere which may impede evaporative heat loss (EHL). This will mainly occur when ambient temperature exceeds the upper limit of individual's thermoneutral zone, or when body temperature rises as result of digging activities. Here we evaluate the effect of ambient temperature on EWL and energy metabolism in the subterranean rodent Ctenomys talarum (tuco-tucos), which inhabits sealed burrows, but makes an extensive use of the aboveground environment. We observed that EWL is increased when ambient temperature rises above thermoneutrality; below this point, evaporation remains stable. Though EWL contributes to total heat loss by increasing ∼1.3 times at 35°C, dry thermal conductance is raised four times. In tuco-tucos' burrows both non-evaporative and, to some extent, evaporative and behavioral mechanisms are essential for body temperature regulation, preventing overheating at high ambient temperatures in a water vapor-saturated atmosphere.

  6. Ambient Temperature and Early Delivery of Singleton Pregnancies

    PubMed Central

    Ha, Sandie; Liu, Danping; Zhu, Yeyi; Kim, Sung Soo; Sherman, Seth; Mendola, Pauline

    2016-01-01

    Background: Extreme temperature is associated with adverse birth outcomes but it is unclear whether it increases early delivery risk.Background: Extreme temperature is associated with adverse birth outcomes but it is unclear whether it increases early delivery risk. Objectives: We aimed to determine the association between ambient temperature and early delivery.Objectives: We aimed to determine the association between ambient temperature and early delivery. Methods: Medical records from 223,375 singleton deliveries from 12 U.S. sites were linked to local ambient temperature. Exposure to hot (> 90th percentile) or cold (< 10th percentile) using site-specific and window-specific temperature distributions were defined for 3-months preconception, 7-week periods during the first two trimesters, 1 week preceding delivery, and whole pregnancy. Poisson regression with generalized estimating equations calculated the relative risk (RR) and 95% confidence interval for early deliveries associated with hot/cold exposures, adjusting for conception month, humidity, site, sex, maternal demographics, parity, insurance, prepregnancy body mass index, pregnancy complications, and smoking or drinking during pregnancy. Acute temperature associations were estimated separately for warm (May–September) and cold season (October–April) in a case-crossover analysis using conditional logistic regression.Methods: Medical records from 223,375 singleton deliveries from 12 U.S. sites were linked to local ambient temperature. Exposure to hot (> 90th percentile) or cold (< 10th percentile) using site-specific and window-specific temperature distributions were defined for 3-months preconception, 7-week periods during the first two trimesters, 1 week preceding delivery, and whole pregnancy. Poisson regression with generalized estimating equations calculated the relative risk (RR) and 95% confidence interval for early deliveries associated with hot/cold exposures, adjusting for conception month

  7. Effect of ambient temperature and light intensity on physiological reactions of heavy broiler chickens.

    PubMed

    Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

    2010-12-01

    The effects of ambient temperature, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. The experiment consisted of a factorial arrangement of treatments in a randomized complete block design. The 9 treatments consisted of 3 levels of temperatures (low = 15.6°C; moderate = 21.1°C; high = 26.7°C) from 21 to 56 d of age and 3 levels of light intensities (0.5, 3.0, 20 lx) from 8 to 56 d of age at 50% RH. A total of 540 Ross 708 chicks were randomly distributed into 9 environmentally controlled chambers (30 male and 30 female chicks/chamber) at 1 d of age. Feed and water were provided ad libitum. Venous blood samples were collected on d 21 (baseline), 28, 42, and 56. High ambient temperature significantly (P ≤ 0.05) reduced BW, partial pressure of CO(2), bicarbonate, hematocrit, hemoglobin, K(+), and Na(+) along with significantly (P ≤ 0.05) elevated pH level, Cl(-), glucose, osmolality, and anion gap concentrations. Partial pressure of O(2) was slightly increased in response to increased ambient temperature. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during high ambient temperature and light intensity exposure did not deteriorate despite a lower partial pressure of CO(2), which consequently increased blood pH because of a compensatory decrease in HCO(3)(-) concentration. Plasma corticosterone was not affected by temperature, light intensity, or their interaction. These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on physiological blood variables, whereas high ambient temperature markedly affected various blood variables without inducing stress in broilers.

  8. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  9. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  10. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  11. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  12. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  13. Ambient temperature influences the neural benefits of exercise.

    PubMed

    Maynard, Mark E; Chung, Chasity; Comer, Ashley; Nelson, Katharine; Tran, Jamie; Werries, Nadja; Barton, Emily A; Spinetta, Michael; Leasure, J Leigh

    2016-02-15

    Many of the neural benefits of exercise require weeks to manifest. It would be useful to accelerate onset of exercise-driven plastic changes, such as increased hippocampal neurogenesis. Exercise represents a significant challenge to the brain because it produces heat, but brain temperature does not rise during exercise in the cold. This study tested the hypothesis that exercise in cold ambient temperature would stimulate hippocampal neurogenesis more than exercise in room or hot conditions. Adult female rats had exercise access 2h per day for 5 days at either room (20 °C), cold (4.5 °C) or hot (37.5 °C) temperature. To label dividing hippocampal precursor cells, animals received daily injections of BrdU. Brains were immunohistochemically processed for dividing cells (Ki67+), surviving cells (BrdU+) and new neurons (doublecortin, DCX) in the hippocampal dentate gyrus. Animals exercising at room temperature ran significantly farther than animals exercising in cold or hot conditions (room 1490 ± 400 m; cold 440 ± 102 m; hot 291 ± 56 m). We therefore analyzed the number of Ki67+, BrdU+ and DCX+ cells normalized for shortest distance run. Contrary to our hypothesis, exercise in either cold or hot conditions generated significantly more Ki67+, BrdU+ and DCX+ cells compared to exercise at room temperature. Thus, a limited amount of running in either cold or hot ambient conditions generates more new cells than a much greater distance run at room temperature. Taken together, our results suggest a simple means by which to augment exercise effects, yet minimize exercise time.

  14. The influence of methanol on the chemical state of PtRu anodes in a high-temperature direct methanol fuel cell studied in situ by synchrotron-based near-ambient pressure x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Saveleva, Viktoriia A.; Daletou, Maria K.; Savinova, Elena R.

    2017-01-01

    Synchrotron radiation-based near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) has recently become a powerful tool for the investigation of interfacial phenomena in electrochemical power sources such as batteries and fuel cells. Here we present an in situ NAP-XPS study of the anode of a high-temperature direct methanol fuel cell with a phosphoric acid-doped hydrocarbon membrane, which reveals an enhanced flooding of the Pt3Ru anode with phosphoric acid in the presence of methanol. An analysis of the electrode surface composition depending on the cell voltage and on the presence of methanol reveals the strong influence of the latter on the extent of Pt oxidation and on the transformation of Ru into Ru (IV) hydroxide.

  15. Impact of Seasonal Variant Temperatures and Laboratory Room Ambient Temperature on Mortality of Rats with Ischemic Brain Injury

    PubMed Central

    Gopalakrishanan, Sivakumar; Babu, Mg. Ramesh; Thangarajan, Rajesh; Punja, Dhiren; Jaganath, Vidyadhara Devarunda; Kanth, Akriti B.; Rao, Mohandas

    2016-01-01

    Introduction A popular rat model for hypoperfusion ischemic brain injury is bilateral common carotid artery occlusion (BCCAO). BCCAO surgery when performed in varying geographical locations and during different seasons of the year is reported to have variable mortality rates. Studies have also documented the diminishing influence of Ketamine-Xylazine (KT-XY) on thermoregulatory functions in rodents. Aim To explore the impact of seasonal variant temperatures and laboratory room ambient temperatures on mortality of rats following BCCAO surgery. Materials and Methods The study has two parts: 1 The first part is an analysis of a three year retrospective data to explore the association between the geographical season (hot summer and cold winter) induced laboratory room ambient temperature variations and the mortality rate in KT-XY anaesthetized BCCAO rats. 2. The second part investigated the effect of conditioned laboratory room ambient temperature (CAT) (23-250C) in KT-XY anaesthetized BCCAO group of rats. Rats were divided into 4 groups(n =8/group) as-Normal control, BCCAO and Sham BCCAO where they were all exposed to unconditioned ambient temperature (UCAT) during their surgery and postoperative care. And finally fourth group rats exposed to CAT during the BCCAO surgery and postoperative care. Results Pearson’s chi-square test indicates a significantly high association (p<0.006) between post-BCCAO mortality and hot season of the year. CAT during the hot season reduced the mortality rate (24% less) in post- BCCAO rats compared to the rats of UCAT. Conclusion Despite seasonal variations in temperature, conditioning the laboratory room ambient temperatures to 23–250C, induces hypothermia in KT-XY anaesthetized ischemic brain injured rodents and improves their survival rate. PMID:27190796

  16. Direct synthesis of hydrogen peroxide in water at ambient temperature.

    PubMed

    Crole, David A; Freakley, Simon J; Edwards, Jennifer K; Hutchings, Graham J

    2016-06-01

    The direct synthesis of hydrogen peroxide (H2O2) from hydrogen and oxygen has been studied using an Au-Pd/TiO2 catalyst. The aim of this study is to understand the balance of synthesis and sequential degradation reactions using an aqueous, stabilizer-free solvent at ambient temperature. The effects of the reaction conditions on the productivity of H2O2 formation and the undesirable hydrogenation and decomposition reactions are investigated. Reaction temperature, solvent composition and reaction time have been studied and indicate that when using water as the solvent the H2O2 decomposition reaction is the predominant degradation pathway, which provides new challenges for catalyst design, which has previously focused on minimizing the subsequent hydrogenation reaction. This is of importance for the application of this catalytic approach for water purification.

  17. The direction and range of ambient temperature change influences yawning in budgerigars (Melopsittacus undulatus).

    PubMed

    Gallup, Andrew C; Miller, Michael L; Clark, Anne B

    2010-05-01

    Comparative research suggests that yawning is a thermoregulatory behavior in homeotherms. Our previous experiments revealed that yawning increased in budgerigars (Melopsittacus undulatus) as ambient temperature was raised toward body temperature (22-->34 degrees C). In this study, we identify the range of temperatures that triggers yawning to rule out the possible effect of changing temperature in any range. To corroborate its thermoregulatory function, we also related the incidence of yawning to other avian thermoregulatory behaviors in budgerigars (e.g., panting, wing venting). In a repeated measures design, 16 budgerigars were exposed to 4 separate 10-min periods of changing temperatures: (a) low-increasing (23-->27 degrees C), (b) high-increasing (27-->33 degrees C), (c) high-decreasing (34-->28 degrees C), and (d) low-decreasing (28-->24 degrees C). Birds yawned significantly more during the high-increasing temperature range, and yawning was positively correlated with ambient temperature across trials. Yawning was also positively correlated with other thermoregulatory behaviors. This research clarifies the previously demonstrated relationship between yawning rate and temperature by providing evidence that the physiological trigger for yawning is related to increasing body temperatures rather than the detection of changing external temperatures.

  18. Donor Acceptor Polymerization Chemistry as a Vehicle to Low Energy Cure of Matrix Resins: Evolution of the 2-Tg Concept to Produce High Tg Polymers at Ambient Temperatures

    DTIC Science & Technology

    1989-03-01

    tetrafunctional acceptors. DSC and TGA analysis of these polymers indicated they possessed the thermal stability necessary for performance in their...be enhanced by choosing comonomers that act as "solvents", and that the "onset of decomposition" temperature as measured by TGA analysis under nitrogen

  19. Effect of ambient temperatures on disinfection efficiency of various sludge treatment technologies.

    PubMed

    Bauerfeld, Katrin

    2014-01-01

    Sewage sludge produced during municipal wastewater treatment has to be treated efficiently in order to reduce impacts on the environment and on public health. In Germany and many countries, large quantities of sludge are reused in agriculture in order to recycle nutrients and organic material. In order to quantify the effect of different ambient temperatures on conventional and advanced sludge treatment technologies as well as on disinfection efficiency, a comprehensive research study was performed at Braunschweig Institute of Technology. The detailed results show that ambient temperature has a strong effect on biological liquid sludge stabilization and on natural dewatering and drying technologies, although microbiological quality of treated sludge, indicated by Escherichia coli concentration, does not meet the requirements for unrestricted reuse in agriculture. Composting and lime treatment of sludge are most efficient on reducing E. coli, as high temperatures and high pH values arise in the material respectively.

  20. The Importance of Ambient Temperature to Growth and the Induction of Flowering

    PubMed Central

    McClung, C. R.; Lou, Ping; Hermand, Victor; Kim, Jin A.

    2016-01-01

    Plant development is exquisitely sensitive to the environment. Light quantity, quality, and duration (photoperiod) have profound effects on vegetative morphology and flowering time. Recent studies have demonstrated that ambient temperature is a similarly potent stimulus influencing morphology and flowering. In Arabidopsis, ambient temperatures that are high, but not so high as to induce a heat stress response, confer morphological changes that resemble the shade avoidance syndrome. Similarly, these high but not stressful temperatures can accelerate flowering under short day conditions as effectively as exposure to long days. Photoperiodic flowering entails a series of external coincidences, in which environmental cycles of light and dark must coincide with an internal cycle in gene expression established by the endogenous circadian clock. It is evident that a similar model of external coincidence applies to the effects of elevated ambient temperature on both vegetative morphology and the vegetative to reproductive transition. Further study is imperative, because global warming is predicted to have major effects on the performance and distribution of wild species and strong adverse effects on crop yields. It is critical to understand temperature perception and response at a mechanistic level and to integrate this knowledge with our understanding of other environmental responses, including biotic and abiotic stresses, in order to improve crop production sufficiently to sustainably feed an expanding world population. PMID:27602044

  1. Habitat type and ambient temperature contribute to bill morphology.

    PubMed

    Luther, David; Greenberg, Russell

    2014-03-01

    Avian bills are iconic structures for the study of ecology and evolution, with hypotheses about the morphological structure of bills dating back to Darwin. Several ecological and physiological hypotheses have been developed to explain the evolution of the morphology of bill shape. Here, we test some of these hypotheses such as the role of habitat, ambient temperature, body size, intraspecific competition, and ecological release on the evolution of bill morphology. Bill morphology and tarsus length were measured from museum specimens of yellow warblers, and grouped by habitat type, sex, and subspecies. We calculated the mean maximum daily temperature for the month of July, the hottest month for breeding specimens at each collecting location. Analysis of covariance models predicted total bill surface area as a function of sex, habitat type, body size, and temperature, and model selection techniques were used to select the best model. Habitat, mangrove forests compared with inland habitats, and climate had the largest effects on bill size. Coastal wetland habitats and island populations of yellow warblers had similar bill morphology, both of which are larger than mainland inland populations. Temperate but not tropical subspecies exhibited sexual dimorphism in bill morphology. Overall, this study provides evidence that multiple environmental factors, such as temperature and habitat, contribute to the evolution of bill morphology.

  2. Response of laying hens to feeding low-protein amino acid-supplemented diets under high ambient temperature: performance, egg quality, leukocyte profile, blood lipids, and excreta pH.

    PubMed

    Torki, Mehran; Mohebbifar, Ahmad; Ghasemi, Hossein Ali; Zardast, Afshin

    2015-05-01

    An experiment was conducted to determine whether, by using a low-protein amino acid-supplemented diet, the health status, stress response, and excreta quality could be improved without affecting the productive performance of heat-stressed laying hens. The requirements for egg production, egg mass, and feed conversion ratio were also estimated using second-order equations and broken-line regression. A total of 150 Lohmann Selected Leghorn (LSL-Lite) hens were divided randomly into five groups of 30 with five replicates of six hens. The hens were raised for an 8-week period (52 to 60 weeks) in wire cages situated in high ambient temperature in an open-sided housing system. The five experimental diets (ME; 2,720 kcal/kg) varied according to five crude protein (CP) levels: normal-CP diet (control, 16.5 % CP) and low-CP diets containing 15.0, 13.5, 12.0, or 10.5 % CP. All experimental diets were supplemented with crystalline amino acids at the levels sufficient to meet their requirements. The results showed that under high temperature conditions, all productive performance and egg quality parameters in the birds fed with 15.0, 13.5, and 12.0 % CP diets were similar to those of birds fed with control diet (16.5 % CP), whereas feeding 10.5 % CP diet significantly decreased egg production and egg mass. Estimations of requirements were of 13.93 and 12.77 % CP for egg production, 14.62 and 13.22 % CP for egg mass, and 12.93 and 12.26 % CP for feed conversion ratio using quadratic and broken-line models, respectively. Egg yolk color index, blood triglyceride level, and excreta acidity were also significantly higher in birds fed with 12.0 and 10.5 % CP diets compared with those of control birds. The heterophil to lymphocyte ratio, as a stress indicator, was significantly decreased by 15.0, 13.5, and 12 % CP diets. On the basis of our findings, reducing dietary CP from 16.5 to 12.0 % and supplementing the diets with the essential amino acids showed merit for improving the

  3. Response of laying hens to feeding low-protein amino acid-supplemented diets under high ambient temperature: performance, egg quality, leukocyte profile, blood lipids, and excreta pH

    NASA Astrophysics Data System (ADS)

    Torki, Mehran; Mohebbifar, Ahmad; Ghasemi, Hossein Ali; Zardast, Afshin

    2015-05-01

    An experiment was conducted to determine whether, by using a low-protein amino acid-supplemented diet, the health status, stress response, and excreta quality could be improved without affecting the productive performance of heat-stressed laying hens. The requirements for egg production, egg mass, and feed conversion ratio were also estimated using second-order equations and broken-line regression. A total of 150 Lohmann Selected Leghorn (LSL-Lite) hens were divided randomly into five groups of 30 with five replicates of six hens. The hens were raised for an 8-week period (52 to 60 weeks) in wire cages situated in high ambient temperature in an open-sided housing system. The five experimental diets (ME; 2,720 kcal/kg) varied according to five crude protein (CP) levels: normal-CP diet (control, 16.5 % CP) and low-CP diets containing 15.0, 13.5, 12.0, or 10.5 % CP. All experimental diets were supplemented with crystalline amino acids at the levels sufficient to meet their requirements. The results showed that under high temperature conditions, all productive performance and egg quality parameters in the birds fed with 15.0, 13.5, and 12.0 % CP diets were similar to those of birds fed with control diet (16.5 % CP), whereas feeding 10.5 % CP diet significantly decreased egg production and egg mass. Estimations of requirements were of 13.93 and 12.77 % CP for egg production, 14.62 and 13.22 % CP for egg mass, and 12.93 and 12.26 % CP for feed conversion ratio using quadratic and broken-line models, respectively. Egg yolk color index, blood triglyceride level, and excreta acidity were also significantly higher in birds fed with 12.0 and 10.5 % CP diets compared with those of control birds. The heterophil to lymphocyte ratio, as a stress indicator, was significantly decreased by 15.0, 13.5, and 12 % CP diets. On the basis of our findings, reducing dietary CP from 16.5 to 12.0 % and supplementing the diets with the essential amino acids showed merit for improving the

  4. Influence of relative humidity and ambient temperature on hydrothermal waves (HTWs) of organic solvent volatile droplets

    NASA Astrophysics Data System (ADS)

    Orejon, Daniel; Kita, Yutaku; Okauchi, Yuya; Fukatani, Yuki; Kohno, Masamichi; Takata, Yasuyuki; Sefiane, Khellil; Kim, Jungho

    2016-11-01

    Droplets of organic solvents undergoing evaporation have been found to display distinctive hydrothermal patterns or HTWs at the liquid-vapor interface. Since the evaporation of mentioned organic solvents in ambient conditions is ubiquitous, in this work we investigate the effect of ambient temperature and relative humidity on the self-generated HTWs by means of infrared thermography. The intensity of the HTWs was found to decrease when lowering the ambient temperature due to a reduction in droplet evaporative cooling. On other hand, the enhancement or suppression of the HTWs was also possible by controlling the relative humidity of the system. Absorption and/or condensation of water vapor onto the evaporating droplet was found to be the main cause for the differences observed on the HTWs retrieved at the liquid-vapor interface. To account for the water adsorbed or condensed we perform in-situ gas chromatography analysis at different droplet lifetimes. Experimental results showed an increase in the amount of water condensed when increasing the relative humidity of the system as expected. In addition, for the same ambient temperature ethanol evaporation was enhanced by high relative humidity. The authors acknowledge the support of WPI-I2CNER.

  5. Symposium on High Power, Ambient Temperature Lithium Batteries, 180th Meeting of the Electrochemical Society, Phoenix, AZ, Oct. 13-17, 1991, Proceedings

    NASA Technical Reports Server (NTRS)

    Clark, W. D. K. (Editor); Halpert, Gerald (Editor)

    1992-01-01

    Papers presented in these proceedings are on the state of the art in high-power lithium batteries, a design analysis of high-power Li-TiS2 battery, the performance and safety features of spiral wound lithium/thionyl chloride cells, the feasibility of a superhigh energy density battery of the Li/BrF3 electrochemical system, and an enhanced redox process of disulfide compounds and their application in high energy storage. Attention is also given to the structure and charge-discharge characteristics of mesophase-pitch based carbons, a study of carbons and graphites as anodes for lithium rechargeable cells, Li metal-free rechargeable Li(1+x)Mn2O4/carbon cells, and rechargeable lithium batteries using V6O13/V5O5 as the positive electrode material. Other papers discuss the electrochemical stability of organic electrolytes in contact with solid inorganic cathode materials, the electrochemical behavior of methyl formate solutions, and the interface between a solid polymer electrolyte and lithium anode.

  6. The E3 ubiquitin ligase HOS1 regulates low ambient temperature-responsive flowering in Arabidopsis thaliana.

    PubMed

    Lee, Jeong Hwan; Kim, Jae Joon; Kim, Soo Hyun; Cho, Hyun Jung; Kim, Joonki; Ahn, Ji Hoon

    2012-10-01

    Ubiquitin-dependent proteolysis regulates multiple aspects of plant growth and development, but little is known about its role in ambient temperature-responsive flowering. In addition to being regulated by daylength, the onset of flowering in many plants can also be delayed by low ambient temperatures. Here, we show that HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1), which encodes an E3 ubiquitin ligase, controls flowering time in response to ambient temperatures (16 and 23°C) and intermittent cold. hos1 mutants flowered early, and were insensitive to ambient temperature, but responded normally to vernalization and gibberellic acid. Genetic analyses suggested that this ambient temperature-insensitive flowering was independent of FLOWERING LOCUS C (FLC). Also, FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) expression was up-regulated in hos1 mutants at both temperatures. The ft tsf mutation almost completely suppressed the early flowering of hos1 mutants at different temperatures, suggesting that FT and TSF are downstream of HOS1 in the ambient temperature response. A lesion in CONSTANS (CO) did not affect the ambient temperature-insensitive flowering phenotype of hos1-3 mutants. In silico analysis showed that FVE was spatiotemporally co-expressed with HOS1. A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. HOS1 physically interacted with FVE and FLK in yeast two-hybrid and co-immunoprecipitation assays. Moreover, hos1 mutants were insensitive to intermittent cold. Collectively, our results suggest that HOS1 acts as a common regulator in the signaling pathways that control flowering time in response to low ambient temperature.

  7. Selective O2 sorption at ambient temperatures via node distortions in Sc-MIL-100

    DOE PAGES

    Sava Gallis, Dorina F.; Chapman, Karena W.; Rodriguez, Mark A.; ...

    2016-04-14

    In this study, oxygen selectivity in metal-organic frameworks (MOFs) at exceptionally high temperatures originally predicted by Density Functional Theory (DFT) and Grand Canonical Monte Carlo (GCMC) modeling is now confirmed by synthesis, sorption metal center access, in particular Sc and Fe. Based on DFT M-O2 binding energies, we chose the large pored MIL-100 framework for metal center access, in particular Sc and Fe. Both resulted in preferential O2 and N2 gas uptake at temperatures ranging from 77 K to ambient temperatures (258 K, 298 K and 313 K).

  8. Thermoregulation responses of broiler chickens to humidity at different ambient temperatures. I. One week of age.

    PubMed

    Lin, H; Zhang, H F; Jiao, H C; Zhao, T; Sui, S J; Gu, X H; Zhang, Z Y; Buyse, J; Decuypere, E

    2005-08-01

    Three trials were conducted to investigate the effect of RH (35, 60, and 85%) on thermoregulation of 1-wk-old broiler chickens at different temperatures (35, 30, and 25 degrees C). The response to humidity in rectal temperature and plumage temperature at the back and breast within 24 h after exposure were recorded at 5 time points (1,4,8,16, and 24 h). Humidity affected the thermoregulation of 1-wk-old broiler chickens by redistributing heat within the body at high, low, and thermoneutral temperatures. The redistribution of heat resulted in decreased rectal temperature and increased peripheral temperature, which were, respectively, beneficial and unfavorable at high and low temperatures. These results suggested that feedback effects of surface temperature on core temperature also exist in poultry, as already observed in mammals, and could be induced not only by changed ambient temperature but also by the changes in humidity at high temperature. The disturbance of thermal equilibrium could not be established solely by changes in RT, but rather core and surface temperatures had to be considered. The daily rhythms in rectal and surface temperatures were affected by humidity.

  9. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  10. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  11. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  12. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  13. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  14. High temperature furnace

    DOEpatents

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  15. O-GlcNAc reports ambient temperature and confers heat resistance on ectotherm development

    PubMed Central

    Radermacher, Pablo T.; Myachina, Faina; Bosshardt, Fritz; Pandey, Rahul; Mariappa, Daniel; Müller, H.-Arno J.; Lehner, Christian F.

    2014-01-01

    Effects of temperature on biological processes are complex. Diffusion is less affected than the diverse enzymatic reactions that have distinct individual temperature profiles. Hence thermal fluctuations pose a formidable challenge to ectothermic organisms in which body temperature is largely dictated by the ambient temperature. How cells in ectotherms cope with the myriad disruptive effects of temperature variation is poorly understood at the molecular level. Here we show that nucleocytoplasmic posttranslational modification of proteins with O-linked GlcNAc (O-GlcNAc) is closely correlated with ambient temperature during development of distantly related ectotherms ranging from the insect Drosophila melanogaster to the nematode Caenorhabditis elegans to the fish Danio rerio. Regulation seems to occur at the level of activity of the only two enzymes, O-GlcNAc transferase and O-GlcNAcase, that add and remove, respectively, this posttranslational modification in nucleus and cytoplasm. With genetic approaches in D. melanogaster and C. elegans, we demonstrate the importance of high levels of this posttranslational modification for successful development at elevated temperatures. Because many cytoplasmic and nuclear proteins in diverse pathways are O-GlcNAc targets, temperature-dependent regulation of this modification might contribute to an efficient coordinate adjustment of cellular processes in response to thermal change. PMID:24706800

  16. O-GlcNAc reports ambient temperature and confers heat resistance on ectotherm development.

    PubMed

    Radermacher, Pablo T; Myachina, Faina; Bosshardt, Fritz; Pandey, Rahul; Mariappa, Daniel; Müller, H-Arno J; Lehner, Christian F

    2014-04-15

    Effects of temperature on biological processes are complex. Diffusion is less affected than the diverse enzymatic reactions that have distinct individual temperature profiles. Hence thermal fluctuations pose a formidable challenge to ectothermic organisms in which body temperature is largely dictated by the ambient temperature. How cells in ectotherms cope with the myriad disruptive effects of temperature variation is poorly understood at the molecular level. Here we show that nucleocytoplasmic posttranslational modification of proteins with O-linked GlcNAc (O-GlcNAc) is closely correlated with ambient temperature during development of distantly related ectotherms ranging from the insect Drosophila melanogaster to the nematode Caenorhabditis elegans to the fish Danio rerio. Regulation seems to occur at the level of activity of the only two enzymes, O-GlcNAc transferase and O-GlcNAcase, that add and remove, respectively, this posttranslational modification in nucleus and cytoplasm. With genetic approaches in D. melanogaster and C. elegans, we demonstrate the importance of high levels of this posttranslational modification for successful development at elevated temperatures. Because many cytoplasmic and nuclear proteins in diverse pathways are O-GlcNAc targets, temperature-dependent regulation of this modification might contribute to an efficient coordinate adjustment of cellular processes in response to thermal change.

  17. Raman Channel Temperature Measurement of SiC MESFET as a Function of Ambient Temperature and DC Power

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Eldridge, Jeffrey J.; Krainsky, Isay L.

    2009-01-01

    Raman spectroscopy is used to measure the junction temperature of a Cree SiC MESFET as a function of the ambient temperature and DC power. The carrier temperature, which is approximately equal to the ambient temperature, is varied from 25 C to 450 C, and the transistor is biased with VDS=10V and IDS of 50 mA and 100 mA. It is shown that the junction temperature is approximately 52 and 100 C higher than the ambient temperature for the DC power of 500 and 1000 mW, respectively.

  18. Effects of transport container and ambient storage temperature on motion characteristics of equine spermatozoa.

    PubMed

    Brinsko, S P; Rowan, K R; Varner, D D; Blanchard, T L

    2000-05-01

    condition. However, time below 4 degrees C was highly correlated (P < 0.05) with a reduction in spermatozoal motility. Mean cooling rates from 20 degrees C to 8 degrees C did not correlate with spermatozoal motility, except when containers were exposed to temporary freezing conditions. No container cooled samples below 6 degrees C in 22 degrees C or 37 degrees C environments except for the ExpectaFoal, in which samples fell below 4 degrees C under all ambient conditions. Ambient temperature affected MOT, PMOT and VCL of semen stored in all containers (P < 0.05) except for the Equitainer II in which motion characteristics remained high and were similar among all ambient temperatures (P > 0.05). Results suggest that stallion semen may be able to tolerate a wider range of cooling rates and storage temperatures than previously considered safe.

  19. The application of exhaled breath analysis in racing Thoroughbreds and the influence of high intensity exercise and ambient temperature on the concentration of carbon monoxide and pH in exhaled breath.

    PubMed

    Cathcart, Michael P; Love, Sandy; Sutton, David G M; Reardon, Richard J M; Hughes, Kristopher J

    2013-08-01

    Analyses of exhaled breath (EB) and exhaled breath condensate (EBC) are non-invasive modalities for assessing the lower airways but these methods have not been applied to Thoroughbred racehorses in training. The aims of this study were to determine whether EB and EBC could be obtained from Thoroughbred racehorses in the field and to investigate the effects of exercise per se and during different ambient temperatures and humidity on exhaled concentrations of nitric oxide (eNO), carbon monoxide (eCO) and EBC pH. EB and EBC samples were obtained from 28 Thoroughbred racehorses pre- and post-exercise during warm (n=23) and/or cold (n=19) ambient temperatures. eNO was detected in 19/84 EB samples. eCO was measured in 39/42 EB samples pre-exercise (median 1.3 ppm) and concentrations decreased significantly post-exercise (median 0.8 ppm, P<0.005) and were associated with ambient temperature. EBC pH was 4.51 ± 0.23 pre-exercise and increased significantly post-exercise (4.79 ± 0.59, P=0.003). The study documented the collection of EB and EBC from Thoroughbred racehorses in a field setting. Alterations in concentrations of volatile gases and EBC pH occurred in response to exercise, and were likely to have been influenced by environmental factors.

  20. Ambient-temperature passive magnetic bearings: Theory and design equations

    SciTech Connect

    Post, R.F.; Ryutov, D.D.

    1997-12-30

    Research has been underway at the Lawrence Livermore National Laboratory to build a theoretical and experimental base for the design of ambient-temperature passive magnetic bearings for a variety of possible applications. in the approach taken the limitations imposed by Earnshaw`s theorem with respect to the stability of passive magnetic bearing systems employing axially symmetric permanent-magnet elements are overcome by employing special combinations of elements, as follows: Levitating and restoring forces are provided by combinations of permanent-magnet-excited elements chosen to provide positive stiffnesses (negative force derivatives) for selected displacements (i.e., those involving translations or angular displacement of the axis of rotation). As dictated by Eamshaw`s theorem, any bearing system thus constructed will be statically unstable for at least one of the remaining possible displacements. Stabilization against this displacement is accomplished by using periodic arrays (`Halbach arrays`) of permanent magnets to induce currents in close-packed inductively loaded circuits, thereby producing negative force derivatives stabilizing the system while in rotation. Disengaging mechanical elements stabilize the system when at rest and when below a low critical speed. The paper discusses theory and equations needed for the design of such systems.

  1. Maternal exposure to ambient temperature and the risks of preterm birth and stillbirth in Brisbane, Australia.

    PubMed

    Strand, Linn B; Barnett, Adrian G; Tong, Shilu

    2012-01-15

    Almost 10% of all births are preterm, and 2.2% are stillbirths. Recent research has suggested that environmental factors may be a contributory cause of these adverse birth outcomes. The authors examined the relation between ambient temperature and preterm birth and stillbirth in Brisbane, Australia, between 2005 and 2009 (n = 101,870). They used a Cox proportional hazards model with livebirth and stillbirth as competing risks. They also examined whether there were periods in pregnancy where exposure to high temperatures had a greater effect. Higher ambient temperatures in the last 4 weeks of the pregnancy increased the risk of stillbirth. The hazard ratio for stillbirth was 0.3 at 12°C relative to the reference temperature of 21°C. The temperature effect was greatest at less than 36 weeks of gestation. There was an association between higher temperature and shorter gestation, as the hazard ratio for livebirth was 0.96 at 15°C and 1.02 at 25°C. This effect was greatest at later gestational ages. These results provide strong evidence of an association between increased temperature and increased risk of stillbirth and shorter gestation.

  2. CHANGES IN AMBIENT TEMPERATURE TRIGGER YAWNING BUT NOT STRETCHING IN RATS

    PubMed Central

    Gallup, Andrew C.; Miller, Ralph R.; Clark, Anne B.

    2010-01-01

    Yawning appears to be involved in arousal, state change, and activity across vertebrates. Recent research suggests that yawning may support effective changes in mental state or vigilance through cerebral cooling. To further investigate the relationship between yawning, state change, and thermoregulation, 12 Sprague-Dawley rats (Rattus norvegicus) were exposed to a total of two hours of ambient temperature manipulation over a period of 48 hours. Using a repeated measures design, each rat experienced a range of increasing (22→32°C), decreasing (32→22°C), and constant temperatures (22°C; 32°C). Yawning and locomotor activity occurred most frequently during initial changes in temperature, irrespective of direction, compared to more extended periods of temperature manipulation. The rate of yawning also diminished during constant high temperatures (32°C) compared to low temperatures (22°C). Unlike yawning, however, stretching was unaffected by ambient temperature variation. These findings are compared to recent work on budgerigars (Melopsittacus undulatus), and the ecological selective pressures for yawning in challenging thermal environments are discussed. The results support previous comparative research connecting yawning with arousal and state change, and contribute to refining the predictions of the thermoregulatory hypothesis across vertebrates. PMID:21132114

  3. High temperature reactors

    NASA Astrophysics Data System (ADS)

    Dulera, I. V.; Sinha, R. K.

    2008-12-01

    With the advent of high temperature reactors, nuclear energy, in addition to producing electricity, has shown enormous potential for the production of alternate transport energy carrier such as hydrogen. High efficiency hydrogen production processes need process heat at temperatures around 1173-1223 K. Bhabha Atomic Research Centre (BARC), is currently developing concepts of high temperature reactors capable of supplying process heat around 1273 K. These reactors would provide energy to facilitate combined production of hydrogen, electricity, and drinking water. Compact high temperature reactor is being developed as a technology demonstrator for associated technologies. Design has been also initiated for a 600 MWth innovative high temperature reactor. High temperature reactor development programme has opened new avenues for research in areas like advanced nuclear fuels, high temperature and corrosion resistant materials and protective coatings, heavy liquid metal coolant technologies, etc. The paper highlights design of these reactors and their material related requirements.

  4. The influence of hypothalamic temperature and ambient temperature on thermoregulatory mechanisms in the pig

    PubMed Central

    Baldwin, B. A.; Ingram, D. L.

    1968-01-01

    1. Two types of temperature fluctuation have been recorded from the preoptic region of the conscious pig. One, which is associated with arousal or movement, and another, which is related to rhythms in respiration and blood pressure. 2. When the pigs were subjected to infra-red irradiation at various ambient temperatures it was found that there was no precise temperature of the preoptic region at which the respiratory frequency increased. 3. Local heating of the preoptic region was effective in increasing the respiratory frequency only when the ambient temperature was above 30° C. 4. Even when both the peripheral temperature and central temperatures were increased there was a delay of several minutes before the onset of panting. 5. Cooling the preoptic region of the hypothalamus prevented the onset of panting in a hot environment, and reduced respiratory frequency in an animal which was already panting. 6. Oxygen consumption was reduced in a cold environment when the preoptic region was warmed, and increased when it was cooled. No increase in oxygen consumption occurred when the hypothalamus was cooled in a hot environment. PMID:5685285

  5. High temperature sensor

    DOEpatents

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  6. High temperature superconductors

    NASA Technical Reports Server (NTRS)

    Wu, Maw-Kuen

    1987-01-01

    The two principle objectives are to develop materials that superconduct at higher temperatures and to better understand the mechanisms behind high temperature superconductivity. Experiments on the thermal reaction, structure, and physical properties of materials that exhibit superconductivity at high temperatures are discussed.

  7. Ambient temperature: a factor affecting performance and physiological response of broiler chickens

    NASA Astrophysics Data System (ADS)

    Donkoh, A.

    1989-12-01

    An experiment was conducted to elucidate the influence of four constant ambient temperatures (20°, 25°, 30° and 35°C) on the performance and physiological reactions of male commercial broiler chicks from 3 to 7 weeks of age. A 12 h light-dark cycle was operated, while relative humidity and air circulation were not controlled. Exposure of broiler chickens to the 20°, 25°, 30° and 35°C treatments showed highly significant ( P<0.0001) depression in growth rate, food intake and efficiency of food utilization, and a significant increase in water consumption for the 30° and 35°C groups. Mortality was, however, not affected by the temperature treatments. Changes in physiological status, such as increased rectal temperatures, decreased concentration of red blood cells, haemoglobin, haematocrit, and total plasma protein were observed in birds housed in the higher temperature (30° and 35°C) environments. Moreover, in these broiler chickens, there was an increased blood glucose concentration and a decreased thyroid gland weight. These results indicate that continuous exposure of broiler chickens to high ambient temperatures markedly affects their performance and physiological response.

  8. Association between the ambient temperature and the occurrence of human Salmonella and Campylobacter infections

    PubMed Central

    Yun, Josef; Greiner, Matthias; Höller, Christiane; Messelhäusser, Ute; Rampp, Albert; Klein, Günter

    2016-01-01

    Salmonella spp. and thermotolerant Campylobacter spp. are the most important causes of human bacterial diarrheal infections worldwide. These bacterial species are influenced by several factors like behaviour of the host, shedding, environment incl. directly or indirectly through ambient temperature, and the infections show seasonality. Therefore, the aim of our study was to investigate the association between the occurrence of human campylobacteriosis and salmonellosis and the ambient temperature. The number of campylobacteriosis and salmonellosis cases in two German metropolises, Munich and Berlin, and three rural regions was analysed with simultaneous consideration of the ambient temperature over a period of four years (2001 to 2004) using regression, time series, and cross-correlation analysis. The statistical analysis showed that an increase in the ambient temperature correlated positively with an increase in human Salmonella and Campylobacter cases. The correlation occurred with a delay of approximately five weeks. The seasonal rise in ambient temperature correlated with increased incidence of bacterial diarrheal infections. PMID:27324200

  9. Cryogenic deformation of high temperature superconductive composite structures

    DOEpatents

    Roberts, Peter R.; Michels, William; Bingert, John F.

    2001-01-01

    An improvement in a process of preparing a composite high temperature oxide superconductive wire is provided and involves conducting at least one cross-sectional reduction step in the processing preparation of the wire at sub-ambient temperatures.

  10. Stability Issues in Ambient-Temperature Passive Magnetic Bearing Systems

    SciTech Connect

    Post, R.F.

    2000-02-17

    The ambient-temperature passive magnetic bearing system developed at the Lawrence Livermore National Laboratory achieves rotor-dynamic stability by employing special combinations of levitating and stabilizing elements. These elements, energized by permanent magnet material, create the magnetic and electrodynamic forces that are required for the stable levitation of rotating systems, such as energy-storage flywheels. Stability criteria, derived from theory, describe the bearing element parameters, i.e., stiffnesses and damping coefficients, that are required both to assure stable levitation (''Earnshaw-stability''), and stability against whirl-type rotor-dynamic instabilities. The work described in this report concerns experimental measurements and computer simulations that address some critical aspects of this overall stability problem. Experimentally, a test device was built to measure the damping coefficient of dampers that employ eddy currents induced in a metallic disc. Another test device was constructed for the purpose of measuring the displacement-dependent drag coefficient of annular permanent magnet bearing elements. In the theoretical developments a computer code was written for the purpose of simulating the rotor-dynamics of our passive bearing systems. This code is capable of investigating rotor-dynamic stability effects for both small-amplitude transient displacements (i.e., those within the linear regime), and for large-amplitude displacements, where non-linear effects can become dominant. Under the latter conditions a bearing system that is stable for small-amplitude displacements may undergo a rapidly growing rotor-dynamic instability once a critical displacement is exceeded. A new result of the study was to demonstrate that stiffness anisotropy of the bearing elements (which can be designed into our bearing system) is strongly stabilizing, not only in the linear regime, but also in the non-linear regime.

  11. Changes of body temperature and thermoregulatory responses of freely moving rats during GABAergic pharmacological stimulation to the preoptic area and anterior hypothalamus in several ambient temperatures.

    PubMed

    Ishiwata, Takayuki; Saito, Takehito; Hasegawa, Hiroshi; Yazawa, Toru; Kotani, Yasunori; Otokawa, Minoru; Aihara, Yasutsugu

    2005-06-28

    Action of gamma-aminobutyric acid (GABA) in the preoptic area and anterior hypothalamus (PO/AH) has been implicated to regulate body temperature (T(b)). However, its precise role in thermoregulation remains unclear. Moreover, little is known about its release pattern in the PO/AH during active thermoregulation. Using microdialysis and telemetry techniques, we measured several parameters related to thermoregulation of freely moving rats during pharmacological stimulation of GABA in normal (23 degrees C), cold (5 degrees C), and hot (35 degrees C) ambient temperatures. We also measured extracellular GABA levels in the PO/AH during cold (5 degrees C) and heat (35 degrees C) exposure combined with microdialysis and high performance liquid chromatography (HPLC). Perfusion of GABA(A) agonist muscimol into the PO/AH increased T(b), which is associated with increased heart rate (HR), as an index of heat production in all ambient temperatures. Although tail skin temperature (T(tail)) as an index of heat loss increased only under normal ambient temperatures, its response was relatively delayed in comparison with HR and T(b), suggesting that the increase in T(tail) was a secondary response to increased HR and T(b). Locomotor activity also increased in all ambient temperatures, but its response was not extraordinary. Interestingly, thermoregulatory responses were different after perfusion of GABA(A) antagonist bicuculline at each ambient temperature. In normal ambient temperature conditions, perfusion of bicuculline had no effect on any parameter. However, under cold ambient temperature, the procedure induced significant hypothermia concomitant with a decrease in HR in spite of hyperactivity and increase of T(tail). It induced hyperthermia with the increase of HR but no additional change of T(tail) in hot ambient temperature conditions. Furthermore, the extracellular GABA level increased significantly during cold exposure. Its release was lower during heat exposure than in a

  12. High temperature refrigerator

    DOEpatents

    Steyert, Jr., William A.

    1978-01-01

    A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

  13. Ultrasonic Sensors for High Temperature Applications

    NASA Astrophysics Data System (ADS)

    Tittmann, Bernhard; Aslan, Mustafa

    1999-05-01

    Many processes take place under conditions other than ambient, and chief among these is high temperature. Examples of high temperature industrial processes are resin transfer molding, molten metal infiltration and rheocasting of composite metals alloys. The interaction of waves with viscous fluids is an additional complication adding to an already complicated problem of operating a sensor at high temperature for extended periods of time. This report attempts to provide an insight into the current state of the art of sensor techniques for in-situ high temperature monitoring.

  14. High-temperature thermodynamics.

    NASA Technical Reports Server (NTRS)

    Margrave, J. L.

    1967-01-01

    High temperature thermodynamics requiring species and phases identification, crystal structures, molecular geometries and vibrational, rotational and electronic energy levels and equilibrium constants

  15. Sub-to super-ambient temperature programmable microfabricated gas chromatography column

    DOEpatents

    Robinson, Alex L.; Anderson, Lawrence F.

    2004-03-16

    A sub- to super-ambient temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by combining a thermoelectric cooler and temperature sensing on the microfabricated column. Sub-ambient temperature programming enables the efficient separation of volatile organic compounds and super-ambient temperature programming enables the elution of less volatile analytes within a reasonable time. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  16. Experiments on the transition from the steady to the oscillatory marangoni convection of a floating-zone under various cold wall temperatures and various ambient air temperature effects

    NASA Astrophysics Data System (ADS)

    Selver, Ramazan

    2005-12-01

    The transition from the steady to the oscillatory Marangoni convection of a floating-zone under various cold wall temperatures and various ambient air temperature effects have been investigated experimentally by heating the sample from above (opposite direction of Marangoni convection and buoyant forces). The heat transfer takes place mainly through conduction as well as the natural convection of the air around the cylindrical liquid bridge. The ambient airflow in the present work is varied by varying the cold wall temperature and ambient air temperature. In this study, the transition from the steady to the oscillatory Marangoni convection flow of a high Prandtl number fluid in a floating half-zone is visualized by means of the already proven method of the "light-cut-technique". The test fluid zone is held in ambient air at +4 °C, +10 °C, +16 °C, +23 °C, and +28 °C. The onset of oscillations, the oscillation level, and oscillation pattern are investigated under various conditions. It is found that the critical temperature difference (ΔTCr) varies substantially when the cold wall temperature and the ambient air temperature are varied.

  17. High temperature measuring device

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  18. The influences of ambient temperature and crude protein levels on performance and serum biochemical parameters in broilers.

    PubMed

    Liu, Q W; Feng, J H; Chao, Z; Chen, Y; Wei, L M; Wang, F; Sun, R P; Zhang, M H

    2016-04-01

    This study was undertaken to investigate the effects of ambient temperature, crude protein levels and their interaction on performance and serum biochemical parameters of broiler chickens. A total of 216 Arbor Acre broiler chickens (108 males and 108 females) were used in a 2 × 3 factorial arrangement and randomly reared at two temperatures (normal temperature: 23 °C; daily cyclic high temperature: 28-32 °C) and fed on three diets with different crude protein levels (153.3, 183.3 or 213.3 g/kg, with constant essential amino acids) from 28 to 42 days of age. Daily cyclic high ambient temperature decreased final body weight, average daily weight gain, average daily feed intake and serum total protein contents (p < 0.001, p < 0.001, p < 0.001, p = 0.008 respectively), but increased feed/gain, mortality, respiratory rate, rectal temperature, serum uric acid contents and serum creatine kinase activity (p = 0.008, p = 0.003, p < 0.0001, p < 0.0001, p < 0.0001, p = 0.003 respectively), irrespective of crude protein levels. At the ambient temperature, reducing crude protein levels resulted in an increase in feed/gain (p < 0.001), but a decrease in serum total protein and uric acid contents. Only serum creatine kinase activity in broiler chickens was interacted by daily cyclic high ambient temperature and dietary crude protein levels (p = 0.003). These results indicated that daily cyclic high ambient temperature had a great effect on performance and serum biochemical parameters in broiler chickens, whereas dietary crude protein levels affected them partially.

  19. High-temperature sensor

    DOEpatents

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  20. Applications of ambient mass spectrometry in high-throughput screening.

    PubMed

    Li, Li-Ping; Feng, Bao-Sheng; Yang, Jian-Wang; Chang, Cui-Lan; Bai, Yu; Liu, Hu-Wei

    2013-06-07

    The development of rapid screening and identification techniques is of great importance for drug discovery, doping control, forensic identification, food safety and quality control. Ambient mass spectrometry (AMS) allows rapid and direct analysis of various samples in open air with little sample preparation. Recently, its applications in high-throughput screening have been in rapid progress. During the past decade, various ambient ionization techniques have been developed and applied in high-throughput screening. This review discusses typical applications of AMS, including DESI (desorption electrospray ionization), DART (direct analysis in real time), EESI (extractive electrospray ionization), etc., in high-throughput screening (HTS).

  1. Low cycle fatigue behavior of polycrystalline Ni3Al alloys at ambient and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Webb, Graham; Antolovich, Stephen D.

    1994-11-01

    The low cycle fatigue (LCF) resistance of polycrystalline Ni3Al has been evaluated at ambient, intermediate (300 °C), and elevated (600 °C) temperatures using strain rates of 10-2/s and 10-4/s. Testing was conducted on a binary and a Cr-containing alloy of similar stoichiometry and B content (hypostoichiometric, 200 wppm B). Test results were combined with electron microscope investigations in order to evaluate microstructural changes during LCF. At ambient and intermediate temperatures, the cyclic constitutive response of both alloys was similar, and the LCF behavior was virtually rate independent. Under these conditions, the alloys rapidly hardened and then gradually softened for the remainder of the life. Initial hardening resulted from the accumulation of dislocation debris within the deformed microstructure, whereas softening was related to localized disordering. For these experimental conditions, crack initiation resulted within persistent slip bands (PSBs). At the elevated temperature, diffusion-assisted deformation resulted in a rate-dependent constitutive response and crack-initiation characteristics. At the high strain rate (10-2/s), continuous cyclic hardening resulted from the accumulation of dislocation debris. At the low strain rate (10-4/s), the diffusion of dislocation debris to grain boundaries resulted in cyclic softening. The elevated temperature LCF resistance was determined by the effect of the constitutive response on the driving force for environmental embrittlement. Chromium additions were observed to enhance LCF performance only under conditions where crack initiation was environmentally driven.

  2. Changes in ambient temperature at the onset of thermoregulatory responses in exercise-trained rats

    NASA Astrophysics Data System (ADS)

    Sugimoto, N.; Sakurada, S.; Shido, O.

    Spontaneous running in a wheel has emerged as a useful method of exercise in rodents. We investigated how exercise training with a running wheel affects ambient temperatures (Ta) at the onset of thermoregulatory responses in rats. Female rats were allowed to run freely in the wheel for 6 months. Sedentary control rats did not exercise during the same period. After the exercise training period, they were loosely restrained and Ta values at the onset of tail skin vasodilation and cold- induced thermogenesis were determined by raising or lowering Ta. Resting levels of core temperature and heat production of the exercise-trained rats were significantly higher than those of the controls. Ta values at the onset of tail skin vasodilation and cold-induced thermogenesis of the exercise-trained rats were higher than those of the controls. The results suggest that, in rats, exercise training with a running wheel elevates ambient temperatures for heat loss and heat production, which may then contribute to maintaining the core temperature at a high level.

  3. Transporting Cells in Semi-Solid Gel Condition and at Ambient Temperature

    PubMed Central

    Wang, Junjian; Chen, Peng; Xu, Jianzhen; Zou, June.X; Wang, Haibin; Chen, Hong-Wu

    2015-01-01

    Mammalian cells including human cancer cells are usually transported in cryovials on dry ice or in a liquid nitrogen vapor shipping vessel between different places at long distance. The hazardous nature of dry ice and liquid nitrogen, and the associated high shipping cost strongly limit their routine use. In this study, we tested the viability and properties of cells after being preserved or shipped over long distance in Matrigel mixture for different days. Our results showed that cells mixed with Matrigel at suitable ratios maintained excellent viability (>90%) for one week at room temperature and preserved the properties such as morphology, drug sensitivity and metabolism well, which was comparable to cells cryopreserved in liquid nitrogen. We also sent cells in the Matrigel mixture via FedEx service to different places at ambient temperature. Upon arrival, it was found that over 90% of the cells were viable and grew well after replating. These data collectively suggested that our Matrigel-based method was highly convenient for shipping live cells for long distances in semi-solid gel condition and at ambient temperature. PMID:26098554

  4. High Temperature Semiconductor Process

    NASA Technical Reports Server (NTRS)

    1998-01-01

    A sputtering deposition system capable of depositing large areas of high temperature superconducting materials was developed by CVC Products, Inc. with the support of the Jet Propulsion Laboratory SBIR (Small Business Innovative Research) program. The system was devleoped for NASA to produce high quality films of high temperature superconducting material for microwave communication system components. The system is also being used to deposit ferroelectric material for capacitors and the development of new electro-optical materials.2002103899

  5. Daily ambient temperature and renal colic incidence in Guangzhou, China: a time-series analysis

    NASA Astrophysics Data System (ADS)

    Yang, Changyuan; Chen, Xinyu; Chen, Renjie; Cai, Jing; Meng, Xia; Wan, Yue; Kan, Haidong

    2016-08-01

    Few previous studies have examined the association between temperature and renal colic in developing regions, especially in China, the largest developing country in the world. We collected daily emergency ambulance dispatches (EADs) for renal colic from Guangzhou Emergency Center from 1 January 2008 to 31 December 2012. We used a distributed-lag nonlinear model in addition to the over-dispersed generalized additive model to investigate the association between daily ambient temperature and renal colic incidence after controlling for seasonality, humidity, public holidays, and day of the week. We identified 3158 EADs for renal colic during the study period. This exposure-response curve was almost flat when the temperature was low and moderate and elevated when the temperature increased over 21 °C. For heat-related effects, the significant risk occurred on the concurrent day and diminished until lag day 7. The cumulative relative risk of hot temperatures (90th percentile) and extremely hot temperatures (99th percentile) over lag days 0-7 was 1.92 (95 % confidence interval, 1.21, 3.05) and 2.45 (95 % confidence interval, 1.50, 3.99) compared with the reference temperature of 21 °C. This time-series analysis in Guangzhou, China, suggested a nonlinear and lagged association between high outdoor temperatures and daily EADs for renal colic. Our findings might have important public health significance to prevent renal colic.

  6. High temperature loop heat pipes

    SciTech Connect

    Anderson, W.G.; Bland, J.J.; Fershtater, Y.; Goncharov, K.A.; Nikitkin, M.; Juhasz, A.

    1995-12-31

    Advantages of loop heat pipes over conventional heat pipes include self-priming during start-up, improved tolerance for noncondensible gas, and ability for ground testing in any orientation. The applications for high temperature, alkali-metal working fluid loop heat pipes include space radiators, and bimodal systems. A high temperature loop heat pipe was fabricated and tested at 850 K, using cesium as the working fluid. Previous loop heat pipes were tested with ambient temperature working fluids at temperatures below about 450 K. The loop heat pipe had a titanium envelope, and a titanium aluminide wick. The maximum cesium loop heat pipe power was only about 600 watts, which was lower the predicted 1,000 W power. The power limitation may be due to a wettability problem with the cesium not completely wetting the titanium aluminide wick. This would reduce the pumping capability of the wick, and the maximum power that the heat pipe could carry. This problem could be solved by using a refractory metal powder wick, since the alkali metals are known to wet refractory metal wicks.

  7. High temperature two component explosive

    DOEpatents

    Mars, James E.; Poole, Donald R.; Schmidt, Eckart W.; Wang, Charles

    1981-01-01

    A two component, high temperature, thermally stable explosive composition comprises a liquid or low melting oxidizer and a liquid or low melting organic fuel. The oxidizer and fuel in admixture are incapable of substantial spontaneous exothermic reaction at temperatures on the order of 475.degree. K. At temperatures on the order of 475.degree. K., the oxidizer and fuel in admixture have an activation energy of at least about 40 kcal/mol. As a result of the high activation energy, the preferred explosive compositions are nondetonable as solids at ambient temperature, and become detonable only when heated beyond the melting point. Preferable oxidizers are selected from alkali or alkaline earth metal nitrates, nitrites, perchlorates, and/or mixtures thereof. Preferred fuels are organic compounds having polar hydrophilic groups. The most preferred fuels are guanidinium nitrate, acetamide and mixtures of the two. Most preferred oxidizers are eutectic mixtures of lithium nitrate, potassium nitrate and sodium nitrate, of sodium nitrite, sodium nitrate and potassium nitrate, and of potassium nitrate, calcium nitrate and sodium nitrate.

  8. Effect of cold ambient temperature on palmar sweating response to vibration stress.

    PubMed

    Ando, Hideo; Noguchi, Ryo; Ishitake, Tatsuya; Matoba, Tsunetaka

    2002-08-01

    We investigated the effect of cold ambient temperature on the palmar sweating response to vibration stress. Ten healthy, male subjects were exposed to eight ambient temperatures (5, 7, 10, 14, 18, 22, 24 and 28 degrees C). At each ambient temperature, each subject gripped the handle of a vibration generator with his left hand with a grasp strength of 49 N. This hand was then exposed to a 125-Hz sinusoidal vibration with an acceleration of 50 m/s(2) (rms) for 3 min at each ambient temperature. Palmar sweating and skin temperature were measured simultaneously on the palm and the fourth finger, respectively, of the subjects' right palm. The palmar sweating response showed a significant change among eight ambient temperatures. The palmar sweating measured at an ambient temperature of 5 degrees C was found to be significantly larger than those measured at 10, 14, 18, 22, 24 and 28 degrees C. Vibration exposure caused a significant increase in the palmar sweating response. Our results suggest that a cold environment plays a significant role in the palmar sweating response to vibration stress.

  9. High-Temperature Superconductivity

    SciTech Connect

    Peter Johnson

    2008-11-05

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  10. Improving ethanol production from alfalfa stems via ambient-temperature acid pretreatment and washing.

    PubMed

    Zhou, Shengfei; Weimer, Paul J; Hatfield, Ronald D; Runge, Troy M; Digman, Matthew

    2014-10-01

    The concept of co-production of liquid fuel (ethanol) along with animal feed on farm was proposed, and the strategy of using ambient-temperature acid pretreatment, ensiling and washing to improve ethanol production from alfalfa stems was investigated. Alfalfa stems were separated and pretreated with sulfuric acid at ambient-temperature after harvest, and following ensiling, after which the ensiled stems were subjected to simultaneous saccharification and fermentation (SSF) for ethanol production. Ethanol yield was improved by ambient-temperature sulfuric acid pretreatment before ensiling, and by washing before SSF. It was theorized that the acid pretreatment at ambient temperature partially degraded hemicellulose, and altered cell wall structure, resulted in improved cellulose accessibility, whereas washing removed soluble ash in substrates which could inhibit the SSF. The pH of stored alfalfa stems can be used to predict the ethanol yield, with a correlation coefficient of +0.83 for washed alfalfa stems.

  11. High-temperature electronics

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-01-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  12. High temperature pressure gauge

    DOEpatents

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  13. High temperature electronics

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1991-03-01

    In recent years, the aerospace propulsion and space power communities have acknowledged a growing need for electronic devices that are capable of sustained high-temperature operation. Aeropropulsion applications for high-temperature electronic devices include engine ground test instrumentation such as multiplexers, analog-to-digital converters, and telemetry systems capable of withstanding hot section engine temperatures in excess of 600 C. Uncooled operation of control and condition monitoring systems in advanced supersonic aircraft would subject the electronics to temperatures in excess of 300 C. Similarly, engine-mounted integrated electronic sensors could reach temperatures which exceed 500 C. In addition to aeronautics, there are many other areas that could benefit from the existence of high-temperature electronic devices. Space applications include power electronic devices for space platforms and satellites. Since power electronics require radiators to shed waste heat, electronic devices that operate at higher temperatures would allow a reduction in radiator size. Terrestrial applications include deep-well drilling instrumentation, high power electronics, and nuclear reactor instrumentation and control. To meet the needs of the applications mentioned previously, the high-temperature electronics (HTE) program at the Lewis Research Center is developing silicon carbide (SiC) as a high-temperature semiconductor material. Research is focused on developing the crystal growth, growth modeling, characterization, and device fabrication technologies necessary to produce a family of SiC devices. Interest in SiC has grown dramatically in recent years due to solid advances in the technology. Much research remains to be performed, but SiC appears ready to emerge as a useful semiconductor material.

  14. High Temperature ESP Monitoring

    SciTech Connect

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  15. High temperature probe

    DOEpatents

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  16. High temperature structural silicides

    SciTech Connect

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  17. Short communication: Changes in body temperature of calves up to 2 months of age as affected by time of day, age, and ambient temperature.

    PubMed

    Hill, T M; Bateman, H G; Suarez-Mena, F X; Dennis, T S; Schlotterbeck, R L

    2016-11-01

    Extensive measurements of calf body temperature are limited in the literature. In this study, body temperatures were collected by taping a data logger to the skin over the tail vein opposing the rectum of Holstein calves between 4 and 60d of age during 3 different periods of the summer and fall. The summer period was separated into moderate (21-33°C average low to high) and hot (25-37°C) periods, whereas the fall exhibited cool (11-19°C) ambient temperatures. Tail temperatures were compared in a mixed model ANOVA using ambient temperature, age of calf, and time of day (10-min increments) as fixed effects and calf as a random effect. Measures within calf were modeled as repeated effects of type autoregressive 1. Calf temperature increased 0.0325°C (±0.00035) per 1°C increase in ambient temperature. Body temperature varied in a distinct, diurnal pattern with time of day, with body temperatures being lowest around 0800h and highest between 1700 and 2200h. During periods of hot weather, the highest calf temperature was later in the day (~2200h). Calf minimum, maximum, and average body temperatures were all higher in hot than in moderate periods and higher in moderate than in cool periods.

  18. High Frequency Acoustic Channel Characterization for Propagation and Ambient Noise

    DTIC Science & Technology

    2006-09-30

    with Michael Porter and the ONR High Frequency Initiative and the ONR PLUSNet program. REFERENCES M. B. Porter and H. P. Bucker, “Gaussian...Harrison and Michael Porter , “A passive fathometer for determining bottom depth and imaging seabed layering using ambient noise”, J. Acoust. Soc. Am., 120

  19. Polymeric electrolytes for ambient temperature lithium batteries. Final report

    SciTech Connect

    Farrington, G.C.

    1994-06-01

    Samples of a plasticized Li{sup +} polymer electrolyte having high conductivity at room temperature were prepared with mixed plasticizer compositions of ethylene carbonate (EC) and propylene carbonate (PC). The influence of EC:PC in varying proportions with 1M LiAsF{sub 6} as the dissolved salt on the chemical and electrochemical properties of the electrolyte was studied. Electrolytes with mixed EC:PC compositions were found to have greater thermal stability, improved lithium and cathode (V{sub 6}O{sub 13}) interfacial properties, and superior mechanical properties compared to those prepared with pure EC and PC. The results of this work are relevant to possible uses of such electrolytes in energy storage technologies.

  20. Dependence of electric strength on the ambient temperature

    SciTech Connect

    Čaja, Alexander E-mail: patrik.nemec@fstroj.uniza.sk Nemec, Patrik E-mail: patrik.nemec@fstroj.uniza.sk Malcho, Milan E-mail: patrik.nemec@fstroj.uniza.sk

    2014-08-06

    At present, the volume concentration of electronic components in their miniaturization to different types of microchips and increasing their performance raises the problem of cooling such elements due to the increasing density of heat flow of heat loss. Compliance with safe operating temperature of active semiconductor element is very closely related to the reliability and durability not only components, but also the entire device. Often it is also necessary to electrically isolate the unit from the side of the cooler air. Cooling demand by natural convection is typical for applications with high operating reliability. To the reliability of the system for removing heat loss increased, it is necessary to minimize need to use the mechanically or electrically powered elements, such as circulation pumps or fans. Experience to date with applications of heat pipe in specific systems appears to be the most appropriate method of cooling.

  1. Dependence of electric strength on the ambient temperature

    NASA Astrophysics Data System (ADS)

    Čaja, Alexander; Nemec, Patrik; Malcho, Milan

    2014-08-01

    At present, the volume concentration of electronic components in their miniaturization to different types of microchips and increasing their performance raises the problem of cooling such elements due to the increasing density of heat flow of heat loss. Compliance with safe operating temperature of active semiconductor element is very closely related to the reliability and durability not only components, but also the entire device. Often it is also necessary to electrically isolate the unit from the side of the cooler air. Cooling demand by natural convection is typical for applications with high operating reliability. To the reliability of the system for removing heat loss increased, it is necessary to minimize need to use the mechanically or electrically powered elements, such as circulation pumps or fans. Experience to date with applications of heat pipe in specific systems appears to be the most appropriate method of cooling.

  2. Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China.

    PubMed

    Dai, Jinping; Chen, Renjie; Meng, Xia; Yang, Changyuan; Zhao, Zhuohui; Kan, Haidong

    2015-08-01

    Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m(3) increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0-21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0-3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs.

  3. Ethylammonium nitrate in high temperature stable microemulsions.

    PubMed

    Zech, Oliver; Thomaier, Stefan; Kolodziejski, Agnes; Touraud, Didier; Grillo, Isabelle; Kunz, Werner

    2010-07-15

    The increasing number of publications reflects the still growing interest in nonaqueous microemulsions containing room-temperature ionic liquids. Recently, we characterized microemulsions composed of the room-temperature ionic liquid ethylammonium nitrate (EAN) as polar phase, dodecane as continuous phase and 1-hexadecyl-3-methyl imidazolium chloride ([C(16)mim][Cl]), an IL that exhibits surfactant properties, and decanol as cosurfactant at ambient temperature. We demonstrate here the high thermal stability of these microemulsions. Along an experimental path, no phase change could be observed visually within a temperature range between 30 degrees C and 150 degrees C. The microemulsions are characterized with quasi-elastic light scattering measurements at ambient temperature and temperature dependent small angle neutron scattering (SANS) experiments between 30 degrees C and 150 degrees C. DLS measurements at ambient temperature indicate a swelling of the formed structures with increasing amount of EAN up to a certain threshold. The SANS experiments were performed below this threshold. The data evaluation of such concentrated systems like microemulsions is possible with the "generalized indirect Fourier transformation" method (GIFT). We evaluated the small angle scattering data via the GIFT method, for comparison we also applied the model of Teubner and Strey (TS) which was often used to describe scattering curves of microemulsions. The GIFT method gives good fits throughout the experimental path, while the TS model gives relatively poor fits. Both, light scattering and SANS results are in agreement with the existence of EAN droplets stabilized by surfactant with dodecane as continuous phase along the whole investigated temperature range. Moreover, these results clearly demonstrate the possibility to formulate high temperature stable microemulsions with ionic liquids at ambient pressure.

  4. High mortality of Red Sea zooplankton under ambient solar radiation.

    PubMed

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  5. High Mortality of Red Sea Zooplankton under Ambient Solar Radiation

    PubMed Central

    Al-Aidaroos, Ali M.; El-Sherbiny, Mohsen M. O.; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M.

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h−1, five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½of maximum values averaged (±SEM) 12±5.6 h−1% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean. PMID:25309996

  6. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  7. High-Temperature Lubricants

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the early 1980's, Lewis Research Center began a program to develop high-temperature lubricants for use on future aircraft flying at three or more times the speed of sound, which can result in vehicle skin temperatures as high as 1,600 degrees Fahrenheit. A material that emerged from this research is a plasma-sprayed, self-lubricating metal- glass-fluoride coating able to reduce oxidation at very high temperatures. Technology is now in commercial use under the trade name Surf-Kote C-800, marketed by Hohman Plating and Manufacturing Inc. and manufactured under a patent license from NASA. Among its uses are lubrication for sliding contact bearings, shaft seals for turbopumps, piston rings for high performance compressors and hot glass processing machinery; it is also widely used in missile and space applications.

  8. [Effects of the microwave exposure at elevated ambient temperature on the thermo-compensatory responses of small laboratory animals].

    PubMed

    Kolganova, O I; Zhavoronkov, L P; Matrënina, V L; Posadskaia, V M

    2003-01-01

    Thermogenic effectiveness of electromagnetic irradiation (EMI) of UHF range (7 GHz) in the dependence on intensity (10-50 mW/cm2) and environmental temperature (22 degrees and 30 degrees C) was studied in experiments with mice and rats. Negative influence of high ambient temperature on thermoregulate responses of animals at microwave exposure was showed. It is concluded that this interaction should been taken into account for hygienic standardization of non-ionizing EMI.

  9. Polymer Membranes with Vertically Oriented Pores Constructed by 2D Freezing at Ambient Temperature.

    PubMed

    Liang, Hong-Qing; Ji, Ke-Jia; Zha, Li-Yun; Hu, Wen-Bing; Ou, Yang; Xu, Zhi-Kang

    2016-06-08

    Polymer membranes with well-controlled and vertically oriented pores are of great importance in the applications for water treatment and tissue engineering. On the basis of two-dimensional solvent freezing, we report environmentally friendly facile fabrication of such membranes from a broad spectrum of polymer resources including poly(vinylidene fluoride), poly(l-lactic acid), polyacrylonitrile, polystyrene, polysulfone and polypropylene. Dimethyl sulfone, diphenyl sulfone, and arachidic acid are selected as green solvents crystallized in the polymer matrices under two-dimensional temperature gradients induced by water at ambient temperature. Parallel Monte Carlo simulations of the lattice polymers demonstrate that the directional process is feasible for each polymer holding suitable interaction with a corresponding solvent. As a typical example of this approach, poly(vinylidene fluoride) membranes exhibit excellent tensile strength, high optical transparence, and outstanding separation performance for the mixtures of yeasts and lactobacilli.

  10. [Heat exchange of the rat in thermoneutral zone temperature and comparison with heat exchange in ambient temperature over and under it].

    PubMed

    Rumiantsev, G V

    2011-08-01

    With the help of thermonetry and general calorimetry body temperature and heat production in ambient temperatures 20 degrees C, 28 degrees C, 33 degrees C were recorded. The experiments showed, that at the temperature 20 degrees C the rectal temperature was changing very little. But in ambient temperature 33 degrees C the rectal temperature was 40.5 +/- 0.1 degrees C.

  11. Pressure induced ionic-superionic transition in silver iodide at ambient temperature.

    PubMed

    Han, Y H; Wang, H B; Troyan, I A; Gao, C X; Eremets, M I

    2014-01-28

    Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω(-1)cm(-1) could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag(+) ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ∼3.4 × 10(-4)-8.6 × 10(-4) cm(2)/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III'. By analyzing the half infinite length Warburg diffusion process, two parameters α and β, which closely relate to the disordered state of Ag(+) ions, have been determined and it was suggested that Ag(+) ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω(-1)cm(-1). Evidence for all three, the diffusion coefficient, α and β, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.

  12. Pressure induced ionic-superionic transition in silver iodide at ambient temperature

    NASA Astrophysics Data System (ADS)

    Han, Y. H.; Wang, H. B.; Troyan, I. A.; Gao, C. X.; Eremets, M. I.

    2014-01-01

    Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω-1cm-1 could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag+ ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ˜3.4 × 10-4-8.6 × 10-4 cm2/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III'. By analyzing the half infinite length Warburg diffusion process, two parameters α and β, which closely relate to the disordered state of Ag+ ions, have been determined and it was suggested that Ag+ ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω-1cm-1. Evidence for all three, the diffusion coefficient, α and β, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.

  13. Triggering of stroke by ambient temperature variation: A case-crossover study in Maputo, Mozambique

    PubMed Central

    Gomes, Joana; Damasceno, Albertino; Carrilho, Carla; Lobo, Vitória; Lopes, Hélder; Madede, Tavares; Pravinrai, Pius; Silva-Matos, Carla; Diogo, Domingos; Azevedo, Ana; Lunet, Nuno

    2015-01-01

    Objectives The effect of ambient temperature as a stroke trigger is likely to differ by type of stroke and to depend on non-transient exposures that influence the risk of this outcome. We aimed to quantify the association between ambient temperature variation and stroke, according to clinical characteristics of the events, and other risk factors for stroke. Methods We conducted a case-crossover study based on a 1-year registry of the hospital admissions due to newly occurring ischemic and hemorrhagic stroke events in Maputo, Mozambique's capital city (N = 593). The case-period was defined as the 7 days before the stroke event, which was compared to two control periods (14–21 days and 21–28 days before the event). We computed humidity- and precipitation-adjusted odds ratios (OR) and 95% confidence intervals (95%CI) using conditional logistic regression. Results An association between minimum temperature declines higher than 2.4 °C in any two consecutive days in the previous week and the occurrence of stroke was observed only for first events (OR = 1.43, 95%CI: 1.15–1.76). Stronger and statistically significant associations were observed for hemorrhagic stroke (OR = 1.50, 95%CI: 1.07–2.09) and among subjects not exposed to risk factors, including smoking, high serum cholesterol or atrial fibrillation. No differences in the effect of temperature were found according to the patients’ vital status 28 days after the event. Conclusions First stroke events, especially of the hemorrhagic type, were triggered by declines in the minimum temperature between consecutive days of the preceding week. PMID:25559679

  14. Impact of ambient temperature on spring-based relative gravimeter measurements

    NASA Astrophysics Data System (ADS)

    Fores, B.; Champollion, C.; Moigne, N. Le; Chery, J.

    2016-10-01

    In this paper, we investigate the impact of ambient temperature changes on the gravity reading of spring-based relative gravimeters. Controlled heating experiments using two Scintrex CG5 gravimeters allowed us to determine a linear correlation (R 2> 0.9) between ambient temperature and gravity variations. The relation is stable and constant for the two CG5 we used: -5 nm/s2/° C. A linear relation is also seen between gravity and residual sensor temperature variations (R 2> 0.75), but contrary to ambient temperature, this relation is neither constant over time nor similar between the two instruments. The linear correction of ambient temperature on the controlled heating time series reduced the standard deviation at least by a factor of 2, to less than 10 nm/s2 . The laboratory results allowed for reprocessing the data gathered on a field survey that originally aimed to characterize local hydrological heterogeneities on a karstic area. The correction of two years of monthly CG5 measurements from ambient temperature variations halved the standard deviation (from 62 to 32 nm/s2 ) and led us to a better hydrological interpretation. Although the origin of this effect is uncertain, we suggest that an imperfect control of the sensor temperature may be involved, as well as a change of the properties of an electronic component.

  15. Impact of ambient temperature on spring-based relative gravimeter measurements

    NASA Astrophysics Data System (ADS)

    Fores, B.; Champollion, C.; Moigne, N. Le; Chery, J.

    2017-03-01

    In this paper, we investigate the impact of ambient temperature changes on the gravity reading of spring-based relative gravimeters. Controlled heating experiments using two Scintrex CG5 gravimeters allowed us to determine a linear correlation ( R 2> 0.9) between ambient temperature and gravity variations. The relation is stable and constant for the two CG5 we used: -5 nm/s2/° C. A linear relation is also seen between gravity and residual sensor temperature variations ( R 2> 0.75), but contrary to ambient temperature, this relation is neither constant over time nor similar between the two instruments. The linear correction of ambient temperature on the controlled heating time series reduced the standard deviation at least by a factor of 2, to less than 10 nm/s2. The laboratory results allowed for reprocessing the data gathered on a field survey that originally aimed to characterize local hydrological heterogeneities on a karstic area. The correction of two years of monthly CG5 measurements from ambient temperature variations halved the standard deviation (from 62 to 32 nm/s2) and led us to a better hydrological interpretation. Although the origin of this effect is uncertain, we suggest that an imperfect control of the sensor temperature may be involved, as well as a change of the properties of an electronic component.

  16. Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Kim, Jayeun; Kim, Ho

    2017-03-01

    We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged <65 (1.08 % [0.17, 2.00 %]) than among those aged ≥65 (1.02 % [0.06, 1.99 %]). Cardiac arrest was inversely related with temperature (1.61 % [0.46, 2.79 %]), while other cardiac arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

  17. Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Kim, Jayeun; Kim, Ho

    2016-08-01

    We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged <65 (1.08 % [0.17, 2.00 %]) than among those aged ≥65 (1.02 % [0.06, 1.99 %]). Cardiac arrest was inversely related with temperature (1.61 % [0.46, 2.79 %]), while other cardiac arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

  18. Enhancement of ANAMMOX activity by low-intensity ultrasound irradiation at ambient temperature.

    PubMed

    Yu, Jin-Jin; Chen, Hui; Zhang, Jue; Ji, Yu-Xin; Liu, Qi-Zhen; Jin, Ren-Cun

    2013-08-01

    This paper aims to investigate the enhancement effect of low intensity intermittent ultrasound irradiation on the efficiency of anaerobic ammonium oxidation (ANAMMOX) process at ambient temperature. With intermittently irradiated (ultrasound intensity of 0.19 w/cm(2), exposure time of 0.2 min), the reactor (RU) had a nitrogen removal rate (NRR) of 5.49 kgTN/m(3)/d at 14.8°C, while the NRR was 1.53 kgTN/m(3)/d in the control reactor (RC). At the end of operation, the contents of polysaccharide, protein, TTC-dehydrogenase and VSS were 6.82 mg/mgVSS, 26.79 mg/mgVSS, 0.58 mgTF/L/H and 10.11 gVSS/L in RU, higher than the levels in the RC. These results demonstrated that it is possible to achieve stable and highly efficient operation in an ANAMMOX reactor at low ambient temperature by implementation of ultrasonication.

  19. SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature

    SciTech Connect

    Robert Rimmer; Jay Benesch; Joseph Preble; Charles Reece

    2005-05-01

    In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maintenance shutdown. We report on the overall SRF performance of the machine after these major disturbances and on efforts to characterize and optimize the new behavior for high-energy running.

  20. Off-design performance of a chemical looping combustion (CLC) combined cycle: effects of ambient temperature

    NASA Astrophysics Data System (ADS)

    Chi, Jinling; Wang, Bo; Zhang, Shijie; Xiao, Yunhan

    2010-02-01

    The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion (CLC) combined cycle. A sensitivity analysis of the CLC reactor system was conducted, which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor. For the ambient temperature variation, three off-design control strategies have been assumed and compared: 1) without any Inlet Guide Vane (IGV) control, 2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature, aside from fuel flow rate adjusting. Results indicate that, compared with the conventional combined cycle, due to the requirement of pressure balance at outlet of the two CLC reactors, CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted. For the first control strategy, temperatures of the two CLC reactors both rise obviously as ambient temperature increases. IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point. Compare with the second strategy, the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.

  1. High temperature storage loop :

    SciTech Connect

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  2. Ambient Temperature Changes and the Impact to Time Measurement Error

    NASA Astrophysics Data System (ADS)

    Ogrizovic, V.; Gucevic, J.; Delcev, S.

    2012-12-01

    Measurements in Geodetic Astronomy are mainly outdoors and performed during a night, when the temperature often decreases very quickly. The time-keeping during a measuring session is provided by collecting UTC time ticks from a GPS receiver and transferring them to a laptop computer. An interrupt handler routine processes received UTC impulses in real-time and calculates the clock parameters. The characteristics of the computer quartz clock are influenced by temperature changes of the environment. We exposed the laptop to different environmental temperature conditions, and calculate the clock parameters for each environmental model. The results show that the laptop used for time-keeping in outdoor measurements should be kept in a stable temperature environment, at temperatures near 20° C.

  3. Type 2 diabetes, but not obesity, prevalence is positively associated with ambient temperature

    PubMed Central

    Speakman, John R.; Heidari-Bakavoli, Sahar

    2016-01-01

    Cold exposure stimulates energy expenditure and glucose disposal. If these factors play a significant role in whole body energy balance, and glucose homeostasis, it is predicted that both obesity and type 2 diabetes prevalence would be lower where it is colder. Previous studies have noted connections between ambient temperature and obesity, but the direction of the effect is confused. No previous studies have explored the link of type 2 diabetes to ambient temperature. We used county level data for obesity and diabetes prevalence across the mainland USA and matched this to county level ambient temperature data. Average ambient temperature explained 5.7% of the spatial variation in obesity and 29.6% of the spatial variation in type 2 diabetes prevalence. Correcting the type 2 diabetes data for the effect of obesity reduced the explained variation to 26.8%. Even when correcting for obesity, poverty and race, ambient temperature explained 12.4% of the variation in the prevalence of type 2 diabetes, and this significant effect remained when latitude was entered into the model as a predictor. When obesity prevalence was corrected for poverty and race the significant effect of temperature disappeared. Enhancing energy expenditure by cold exposure will likely not impact obesity significantly, but may be useful to combat type 2 diabetes. PMID:27477955

  4. Effect of Ambient Design Temperature on Air-Cooled Binary Plant Output

    SciTech Connect

    Dan Wendt; Greg Mines

    2011-10-01

    Air-cooled binary plants are designed to provide a specified level of power production at a particular air temperature. Nominally this air temperature is the annual mean or average air temperature for the plant location. This study investigates the effect that changing the design air temperature has on power generation for an air-cooled binary plant producing power from a resource with a declining production fluid temperature and fluctuating ambient temperatures. This analysis was performed for plants operating both with and without a geothermal fluid outlet temperature limit. Aspen Plus process simulation software was used to develop optimal air-cooled binary plant designs for specific ambient temperatures as well as to rate the performance of the plant designs at off-design operating conditions. Results include calculation of annual and plant lifetime power generation as well as evaluation of plant operating characteristics, such as improved power generation capabilities during summer months when electric power prices are at peak levels.

  5. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  6. High-Temperature Superconductivity

    ScienceCinema

    Peter Johnson

    2016-07-12

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  7. Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

    PubMed

    Karanjekar, Richa V; Bhatt, Arpita; Altouqui, Said; Jangikhatoonabad, Neda; Durai, Vennila; Sattler, Melanie L; Hossain, M D Sahadat; Chen, Victoria

    2015-12-01

    Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual.

  8. HIGH TEMPERATURE THERMOCOUPLE

    DOEpatents

    Eshayu, A.M.

    1963-02-12

    This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact. The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream. (AEC)

  9. Low-temperature-grown continuous graphene films from benzene by chemical vapor deposition at ambient pressure

    PubMed Central

    Jang, Jisu; Son, Myungwoo; Chung, Sunki; Kim, Kihyeun; Cho, Chunhum; Lee, Byoung Hun; Ham, Moon-Ho

    2015-01-01

    There is significant interest in synthesizing large-area graphene films at low temperatures by chemical vapor deposition (CVD) for nanoelectronic and flexible device applications. However, to date, low-temperature CVD methods have suffered from lower surface coverage because micro-sized graphene flakes are produced. Here, we demonstrate a modified CVD technique for the production of large-area, continuous monolayer graphene films from benzene on Cu at 100–300 °C at ambient pressure. In this method, we extended the graphene growth step in the absence of residual oxidizing species by introducing pumping and purging cycles prior to growth. This led to continuous monolayer graphene films with full surface coverage and excellent quality, which were comparable to those achieved with high-temperature CVD; for example, the surface coverage, transmittance, and carrier mobilities of the graphene grown at 300 °C were 100%, 97.6%, and 1,900–2,500 cm2 V−1 s−1, respectively. In addition, the growth temperature was substantially reduced to as low as 100 °C, which is the lowest temperature reported to date for pristine graphene produced by CVD. Our modified CVD method is expected to allow the direct growth of graphene in device manufacturing processes for practical applications while keeping underlying devices intact. PMID:26658923

  10. Low-temperature-grown continuous graphene films from benzene by chemical vapor deposition at ambient pressure

    NASA Astrophysics Data System (ADS)

    Jang, Jisu; Son, Myungwoo; Chung, Sunki; Kim, Kihyeun; Cho, Chunhum; Lee, Byoung Hun; Ham, Moon-Ho

    2015-12-01

    There is significant interest in synthesizing large-area graphene films at low temperatures by chemical vapor deposition (CVD) for nanoelectronic and flexible device applications. However, to date, low-temperature CVD methods have suffered from lower surface coverage because micro-sized graphene flakes are produced. Here, we demonstrate a modified CVD technique for the production of large-area, continuous monolayer graphene films from benzene on Cu at 100-300 °C at ambient pressure. In this method, we extended the graphene growth step in the absence of residual oxidizing species by introducing pumping and purging cycles prior to growth. This led to continuous monolayer graphene films with full surface coverage and excellent quality, which were comparable to those achieved with high-temperature CVD; for example, the surface coverage, transmittance, and carrier mobilities of the graphene grown at 300 °C were 100%, 97.6%, and 1,900-2,500 cm2 V-1 s-1, respectively. In addition, the growth temperature was substantially reduced to as low as 100 °C, which is the lowest temperature reported to date for pristine graphene produced by CVD. Our modified CVD method is expected to allow the direct growth of graphene in device manufacturing processes for practical applications while keeping underlying devices intact.

  11. High temperature thermometric phosphors

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub x},Eu{sub y} wherein: 0.1 wt % {<=} x {<=} 20 wt % and 0.1 wt % {<=} y {<=} 20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  12. High temperature thermometric phosphors

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  13. Effects of RVP on emissions at 20F ambient temperature. Technical report

    SciTech Connect

    McIntyre, B.; Enns, P.

    1991-12-01

    The Environmental Protection Agency is currently proposing rules that will establish cold carbon monoxide (CO) emission standards. The vehicle emission certification testing will be performed using the Federal Test Procedure (FTP) driving cycle at 20 F ambient temperature. Questions have arisen as to whether the Reid Vapor Pressure (RVP) of the fuel used for the FTP test will have an impact on cold temperature CO emissions. The purpose of the report is to describe the test program used to determine whether the RVP of fuel could affect the CO exhaust emissions of recent technology motor vehicles tested at 20 F ambient temperature.

  14. Influence of ambient temperatures on the production of restraint ulcers in the rat

    NASA Technical Reports Server (NTRS)

    Buchel, L.; Gallaire, D.

    1980-01-01

    A study of the influence of ambient temperature on the production of restraint ulcers in the rat is described. It concludes that the production of restrain ulcers, is favored by the reduction of the environmental temperature, whether the rat has been subjected to a fast or not.

  15. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment ENVIRONMENTAL... power line voltage and ambient temperature. (a) Overview. (1) This test procedure is a combined... temperature. Tests shall be conducted in a temperature-controlled environment over four 6-hour time...

  16. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-12-31

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with super-heated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200{degrees}C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220{degrees}C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: (1) At relative pressures over 0.6 the capillarity forces are very important. (2) There is no significant temperature effect. (3) Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. (4) Pores smaller than 15 {Angstrom} do not contribute to the adsorbed mass.

  17. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-01-24

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with superheated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200 °C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220 °C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: 1. At relative pressures over 0.6 the capillarity forces are very important. 2. There is no significant temperature effect. 3. Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. 4. Pores smaller than 15 Å do not contribute to the adsorbed mass.

  18. Acute Changes in Ambient Temperature Are Associated With Adverse Changes in Cardiac Rhythm

    PubMed Central

    Wasserman, Erin B.; Zareba, Wojciech; Utell, Mark J.; Oakes, David; Hopke, Philip K.; Frampton, Mark; Chalupa, David; Beckett, William; Rich, David Q.

    2014-01-01

    Background Both increases and decreases in ambient temperature have been associated with increased cardiovascular mortality and morbidity. However, the mechanism(s) remain unclear. Objectives We examined associations between biomarkers of pathways thought to, in part, explain these associations and changes in ambient temperature in a panel of predominantly post-myocardial infarction or post-stent patients. Methods We studied 76 subjects who had a recent coronary event and were participating in a cardiac rehabilitation program. In these patients, we measured heart rate variability, repolarization, and baroreflex sensitivity parameters using Holter ECG recordings before and during supervised, graded, twice weekly, exercise sessions. Hourly temperature measurements were made at a monitoring site near the rehabilitation center. Results Using linear mixed models, we observed decreases in rMSSD (square root of the mean of the sum of the squared differences between adjacent NN intervals) and deceleration capacity, associated with increases in ambient temperature in the previous four days. Additionally, decreased rMSSD was associated with both increasing temperature (mean in previous 6 hours) in the summer and decreasing temperature (mean in the previous 3 weeks) in the winter. Conclusions In a panel of cardiac rehabilitation patients, changes in ambient temperature were associated with decreases in markers of heart rate variability and baroreflex sensitivity, which may lead to increased risk of arrhythmic events and sudden death in post-infarction patients. PMID:25368681

  19. High temperature materials characterization

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1990-01-01

    A lab facility for measuring elastic moduli up to 1700 C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points. The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region. The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology.

  20. High temperature future

    SciTech Connect

    Sheinkopf, K.

    1994-09-01

    During the past few years, there have been dramatic accomplishments and success of high temperature solar thermal systems and significant development of these systems. High temperature technologies, about 500 F and higher, such as dish engines, troughs, central receiver power towers and solar process heat systems, have been tested, demonstrated and used in an array of applications, including many cost-effective utility bulk power production and demand side supply projects in the United States. Large systems provide power and hot water to prisons, schools, nursing homes and other institutions. Joint ventures with industry, utility projects, laboratory design assistance and other activities are building a solid industry of US solar thermal systems ready for use today.

  1. High Temperature Thermosets

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1999-01-01

    A thermoset or network polymer is an organic material where the molecules are tied together through chemical bonds (crosslinks) and therefore they cannot move past one another. As a result, these materials exhibit a certain degree of dimensional stability. The chemical composition and the degree of crosslink density of the thermoset have a pronounced effect upon the properties. High temperature thermosets offer a favorable combination of properties that makes them attractive for many applications. Their most important features are the excellent processability particularly of the low molecular weight precusor forms, the chemical and solvent resistance and the dimensional stability. The market for high temperature thermosets will increase as new uses for them are uncovered and new thermosets with better combinations of properties are developed.

  2. Experimental and casework validation of ambient temperature corrections in forensic entomology.

    PubMed

    Johnson, Aidan P; Wallman, James F; Archer, Melanie S

    2012-01-01

    This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences.

  3. Compensation for effects of ambient temperature on rare-earth doped fiber optic thermometer

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.; Sotomayor, J. L.; Krasowski, M. J.; Eustace, J. G.

    1989-01-01

    Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed.

  4. Compensation for effects of ambient temperature on rare-earth doped fiber optic thermometer

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.; Sotomayor, J. L.; Krasowski, M. J.; Eustace, J. G.

    1990-01-01

    Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed.

  5. Crack growth in ASME SA-105 grade 2 steel in hydrogen at ambient temperature

    NASA Technical Reports Server (NTRS)

    Walter, R. J.

    1975-01-01

    Cyclic-load crack growth measurements were performed on ASME SA-105 Grade 2 steel specimens exposed to 10,000- and 15,000-psi hydrogen and to 5000-psi helium, all at ambient temperatures. The cyclic-load crack growth rate was found to be faster in high-pressure hydrogen than in helium. Cyclic-load crack growth rates in this steel were not reduced by preloading in air to a stress intensity of 1.5 times the cyclic K sub max in hydrogen. There are indications that holding under load in hydrogen, and loading and unloading in helium retards hydrogen-accelerated cyclic-load crack growth. Cyclic frequency and R (ratio of K sub min/k sub max) were important variables determining crack growth rate. The crack growth rate increased as a logarithm of the cycle duration and decreased with increasing R.

  6. Small changes in ambient temperature affect alternative splicing in Arabidopsis thaliana

    PubMed Central

    Streitner, Corinna; Simpson, Craig G.; Shaw, Paul; Danisman, Selahattin; Brown, John W.S.; Staiger, Dorothee

    2013-01-01

    Alternative splicing (AS) gives rise to multiple mRNA isoforms from the same gene, providing possibilities to regulate gene expression beyond the level of transcription. In a recent paper in Nucleic Acids Research we used a high resolution RT-PCR based panel to study changes in AS patterns in plants with altered levels of an hnRNP-like RNA-binding protein in Arabidopsis thaliana. Furthermore, we detected significant changes in AS patterns between different Arabidopsis ecotypes. Here we investigated how small changes in ambient temperature affect AS. We found significant changes in AS for 12 of 28 investigated events (43%) upon transfer of Arabidopsis plants from 20°C to 16°C and for 6 of the 28 investigated events (21%) upon transfer from 20°C to 24°C. PMID:23656882

  7. Mouse reproductive fitness is maintained up to an ambient temperature of 28℃ when housed in individually-ventilated cages.

    PubMed

    Helppi, J; Schreier, D; Naumann, R; Zierau, O

    2016-08-01

    Production of genetically-modified mice is strongly dependent on environmental conditions. Mice are commonly housed at 22℃, which is significantly lower than their thermoneutral zone. But, when given a choice, mice often seem to prefer higher ambient temperatures. In the current study we investigated the effect of higher ambient temperature on the production of transgenic mice, with emphasis on embryo and sperm yield and quality. Mice (C57BL/6JOlaHsd) were housed under four different ambient temperatures (22, 25, 28 and 30℃). Female mice were superovulated, and mated with males. As indicators for reproductive fitness, the success of the mating was observed, including embryo yield and quality, as well as sperm count, motility and progressivity. Female mice were found to produce high amounts of high quality embryos from 22 to 28℃. Sperm count dropped continuously from 22 to 30℃, but sperm motility and progressivity remained high from 22 to 28℃. We conclude that mice can be housed at significantly higher temperatures than is commonly recommended without compromising embryo production and quality, or sperm quality. These results could lead to fundamental changes in how mouse facilities are built and operated - especially in warmer climates whereby energy consumption and therefore costs could be significantly reduced.

  8. Splicing-related genes are alternatively spliced upon changes in ambient temperatures in plants

    PubMed Central

    Bucher, Johan; Lammers, Michiel; Busscher-Lange, Jacqueline; Bonnema, Guusje; Rodenburg, Nicole; Proveniers, Marcel C. G.; Angenent, Gerco C.

    2017-01-01

    Plants adjust their development and architecture to small variations in ambient temperature. In a time in which temperatures are rising world-wide, the mechanism by which plants are able to sense temperature fluctuations and adapt to it, is becoming of special interest. By performing RNA-sequencing on two Arabidopsis accession and one Brassica species exposed to temperature alterations, we showed that alternative splicing is an important mechanism in ambient temperature sensing and adaptation. We found that amongst the differentially alternatively spliced genes, splicing related genes are enriched, suggesting that the splicing machinery itself is targeted for alternative splicing when temperature changes. Moreover, we showed that many different components of the splicing machinery are targeted for ambient temperature regulated alternative splicing. Mutant analysis of a splicing related gene that was differentially spliced in two of the genotypes showed an altered flowering time response to different temperatures. We propose a two-step mechanism where temperature directly influences alternative splicing of the splicing machinery genes, followed by a second step where the altered splicing machinery affects splicing of downstream genes involved in the adaptation to altered temperatures. PMID:28257507

  9. Ambient-temperature creep failure of silver-aided diffusion bonds between steel

    SciTech Connect

    Henshall, G.A.; Kassner, M.E.; Rosen, R.S.

    1990-01-15

    It has long been known that thin (e.g., 1 {mu}m {minus} 1 mm) interlayer bonds between higher strength base materials may have high ultimate tensile or rupture strengths despite the relatively low strength of the filler metal. The high strength of the joint is due to the mechanical constraint provided by the stronger base metals which restricts transverse contraction of the interlayer. The constraint produces a triaxial state or stress and reduces the effective stress, thus reducing the tendency for the interlayer to plastically deform. Plasticity of the base metal reduces the constraint and decreases the strength of the bond. The purpose of this work was twofold. First, the validity of the base-metal- accelerated'' delayed-failure theory for bonds utilizing plastic base metals was checked. Creep-rupture tests were performed on diffusion-bonded specimens using silver interlayers deposited by planar-magnetron sputtering (PMS), a physical vapor-deposition process. The PMS process was preferred because of the superior quality and strength of the bond and because this modern low-temperature joining process is increasingly utilized for joining ceramic and composite materials. The role of plastic base metals in the fracture process was further investigated by conducting tensile-rupture tests of diffusion bonds made with stainless steel base metals of different yield strengths, and therefore different creep rates. The second purpose was to determine whether delayed failure occurs in interlayer bonds between elastic base metals, which do not creep over the range of applied stresses. This question is particularly relevant since many alloys, ceramics and composites fall within this category. Again, ambient and near-ambient temperature creep-rupture tests were performed at a variety of stresses below the UTS of the bond. 25 refs., 7 figs.

  10. Effect of Volatility and Oxygenates on Driveability at Intermediate Ambient Temperatures

    DTIC Science & Technology

    1992-03-01

    oxygenate blends. The pro- gram was conducted in Yakima , Washington , from October 9 through November 18, 1989. Test temperatures were 301F to 56F. Members... cold -start and warmup driveability of late model vehicles at intermediate ambient temperatures . Front-end volatility was measured by RVP, and mid-range...vehicle fuel system (carbureted, TBI, PFI), vehicles within the fuel system, transmission type, and run temperature were siqnificant cold -start and warmup

  11. Selective O2 sorption at ambient temperatures via node distortions in Sc-MIL-100

    SciTech Connect

    Sava Gallis, Dorina F.; Chapman, Karena W.; Rodriguez, Mark A.; Greathouse, Jeffery A.; Parkes, Marie V.; Nenoff, Tina M.

    2016-04-14

    In this study, oxygen selectivity in metal-organic frameworks (MOFs) at exceptionally high temperatures originally predicted by Density Functional Theory (DFT) and Grand Canonical Monte Carlo (GCMC) modeling is now confirmed by synthesis, sorption metal center access, in particular Sc and Fe. Based on DFT M-O2 binding energies, we chose the large pored MIL-100 framework for metal center access, in particular Sc and Fe. Both resulted in preferential O2 and N2 gas uptake at temperatures ranging from 77 K to ambient temperatures (258 K, 298 K and 313 K).

  12. The influence of food intake and ambient temperature on the rate of thyroxine utilization.

    PubMed Central

    Ingram, D L; Kaciuba-Uscilko, H

    1977-01-01

    Young growing pigs of both sexes were subjected to changes in (1) energy intake, (2) ambient temperature, and (3) bulk of food. The rate of disappearance of injected 125I-labelled thyroxine from the plasma (K) was measured. An analysis of variance revealed that the effect attributable to changes in the energy content of the food intake was statistically significant (P less 0-01). A change in ambient temperature had no statistically significant effect on K, nor did a change in the bulk of food when energy intake was constant (P less than 0-05). PMID:903901

  13. Lithium doping on covalent organic framework-320 for enhancing hydrogen storage at ambient temperature

    NASA Astrophysics Data System (ADS)

    Xia, Liangzhi; Liu, Qing

    2016-12-01

    Density Functional Theory (DFT) combines with grand canonical Monte Carlo (GCMC) simulations are performed to explore the effect of Li doping on the hydrogen storage capability of COF-320. The results show that the interaction energy between the H2 and the Li-doped COF-320 is about three times higher than that of pristine COF-320. GCMC simulations are employed to study the hydrogen uptake of Li-doped COF-320 at ambient temperature, further confirm that the lithium doping can improve the hydrogen uptake at ambient temperature. Our results demonstrate that Li-doped COFs have good potential in the field of hydrogen storage.

  14. High temperature superconducting compounds

    NASA Astrophysics Data System (ADS)

    Goldman, Allen M.

    1992-11-01

    The major accomplishment of this grant has been to develop techniques for the in situ preparation of high-Tc superconducting films involving the use of ozone-assisted molecular beam epitaxy. The techniques are generalizable to the growth of trilayer and multilayer structures. Films of both the DyBa2Cu3O(7-x) and YBa2Cu3O(7-x) compounds as well as the La(2-x)Sr(x)CuO4 compound have been grown on the usual substrates, SrTiO3, YSZ, MgO, and LaAlO3, as well as on Si substrates without any buffer layer. A bolometer has been fabricated on a thermally isolated SiN substrate coated with YSZ, an effort carried out in collaboration with Honeywell Inc. The deposition process facilitates the fabrication of very thin and transparent films creating new opportunities for the study of superconductor-insulator transitions and the investigation of photo-doping with carriers of high temperature superconductors. In addition to a thin film technology, a patterning technology has been developed. Trilayer structures have been developed for FET devices and tunneling junctions. Other work includes the measurement of the magnetic properties of bulk single crystal high temperature superconductors, and in collaboration with Argonne National Laboratory, measurement of electric transport properties of T1-based high-Tc films.

  15. Interactions Between Housing Density and Ambient Temperature in the Cage Environment: Effects on Mouse Physiology and Behavior

    PubMed Central

    Toth, Linda A; Trammell, Rita A; Ilsley-Woods, Megan

    2015-01-01

    To determine how housing density and ambient temperature interact to influence the physiology and behavior of mice, we systematically varied housing density (1 to 5 mice per cage) and ambient temperature (22, 26, or 30 °C) and measured effects on body weight, food intake, diurnal patterns of locomotor activity and core temperature, fecal corticosterone, and serum cytokine and adipokine panels. Temperatures inside cages housing 5 mice were 1 to 2 °C higher than the ambient temperature. As the housing density decreased, in-cage temperatures began to fall at a density of 2 or 3 mice per cage and did not differ from ambient temperature at 1 mouse per cage. Ambient temperature, but not housing density, significantly affected food intake. Although neither ambient temperature nor housing density affected core temperature or activity, hyperthermia and behavioral activation occurred during the 12-h period after cage change. Fecal concentrations of corticosterone metabolites and serum cytokines, chemokines, insulin, and leptin were not influenced by cage density and were only sporadically influenced by ambient temperature. Our data document that the number of mice housed per cage influences the intracage environmental conditions and that ambient temperature influences food intake even when temperatures are within or near recommended or thermoneutral ranges. We conclude that investigators should be cautious when changing the number of mice housed in a cage over the course of a study, because doing so significantly alters the cage environment to which remaining mice are exposed. PMID:26632780

  16. Ambient temperature and risk of first primary basal cell carcinoma: a nationwide United States cohort study

    PubMed Central

    Freedman, D. Michal; Kitahara, Cari M.; Linet, Martha S.; Alexander, Bruce H.; Neta, Gila; Little, Mark; Cahoon, Elizabeth K.

    2015-01-01

    The Earth's surface is warming and animal studies have shown higher temperatures promote ultraviolet radiation (UVR) skin carcinogenesis. There are, however, no population studies of long-term temperature exposure and basal cell carcinoma (BCC) risk. We linked average lifetime summer ambient temperatures (based on weather station data) and satellite-based UVR estimates to self-reported lifetime residences in the U.S. Radiologic Technologists' cohort. We assessed the relationship between time-dependent average lifetime summer ambient temperature (20-year lag) in quintiles and BCC in whites, using Cox proportional hazards regression. Risks were adjusted for time-dependent lagged average lifetime UVR and time outdoors, body mass index, eye color, and sex (baseline hazard stratified on birth cohort). During a median 19.4 years follow-up, we identified 3,556 BCC cases. There was no significant trend in risk between temperature and BCC. However, BCC risk was highest in the fourth quintile of temperature (Q4 vs. Q1; hazards ratio (HR)=1.18; 95% confidence interval (CI) = 1.06–1.31, p-trend =0.09). BCC risk was strongly related to average lifetime ambient UVR exposure (Q5 vs. Q1; HR = 1.54 (95% CI = 1.35–1.75, p-trend= <0.001)). Future studies of temperature and BCC risk should include a broad range of UVR and temperature values, along with improved indicators of exposure to temperatures and UVR. PMID:25996074

  17. Ambient temperature and risk of first primary basal cell carcinoma: A nationwide United States cohort study.

    PubMed

    Michal Freedman, D; Kitahara, Cari M; Linet, Martha S; Alexander, Bruce H; Neta, Gila; Little, Mark P; Cahoon, Elizabeth K

    2015-07-01

    The Earth's surface is warming and animal studies have shown higher temperatures promote ultraviolet radiation (UVR) skin carcinogenesis. There are, however, no population studies of long-term temperature exposure and basal cell carcinoma (BCC) risk. We linked average lifetime summer ambient temperatures (based on weather station data) and satellite-based UVR estimates to self-reported lifetime residences in the U.S. Radiologic Technologists' cohort. We assessed the relationship between time-dependent average lifetime summer ambient temperature (20-year lag) in quintiles and BCC in whites, using Cox proportional hazards regression. Risks were adjusted for time-dependent lagged average lifetime UVR and time outdoors, body mass index, eye color, and sex (baseline hazard stratified on birth cohort). During a median 19.4 years follow-up, we identified 3556 BCC cases. There was no significant trend in risk between temperature and BCC. However, BCC risk was highest in the fourth quintile of temperature (Q4 vs. Q1; hazards ratio (HR)=1.18; 95% confidence interval (CI)=1.06-1.31, p-trend=0.09). BCC risk was strongly related to average lifetime ambient UVR exposure (Q5 vs. Q1; HR=1.54 (95% CI=1.35-1.75, p-trend=<0.001)). Future studies of temperature and BCC risk should include a broad range of UVR and temperature values, along with improved indicators of exposure to temperatures and UVR.

  18. Ambient Temperature and the Risk of Preterm Birth in Guangzhou, China (2001–2011)

    PubMed Central

    He, Jian-Rong; Liu, Yu; Xia, Xiao-Yan; Ma, Wen-Jun; Lin, Hua-Liang; Kan, Hai-Dong; Lu, Jin-Hua; Feng, Qiong; Mo, Wei-Jian; Wang, Ping; Xia, Hui-Min; Qiu, Xiu; Muglia, Louis J.

    2015-01-01

    Background: Although effects of weather changes on human health have been widely reported, there is limited information regarding effects on pregnant women in developing countries. Objective: We investigated the association between maternal exposure to ambient temperature and the risk of preterm birth (< 37 weeks of gestation) in Guangzhou, China. Methods: We used a Cox proportional hazards model to estimate associations between preterm birth and average temperature during each week of gestation, with weekly temperature modeled as a time-varying exposure during four time windows: 1 week (the last week of the pregnancy), 4 weeks (the last 4 weeks of the pregnancy), late pregnancy (gestational week 20 onward), and the entire pregnancy. Information on singleton vaginal birth between 2001 and 2011 was collected. Daily meteorological data during the same period were obtained from the Guangzhou Meteorological Bureau. Results: A total of 838,146 singleton vaginal births were included, among which 47,209 (5.6%) were preterm births. High mean temperatures during the 4 weeks, late pregnancy, and the entire pregnancy time windows were associated with an increased risk of preterm birth. Compared with the median temperature (24.4°C), weekly exposures during the last 4 weeks of the pregnancy to extreme cold (7.6°C, the 1st percentile) and extreme heat (31.9°C, the 99th percentile) were associated with 17.9% (95% CI: 10.2, 26.2%) and 10.0% (95% CI: 2.9, 17.6%) increased risks of preterm birth, respectively. The association between extreme heat and preterm birth was stronger for preterm births during weeks 20–31 and 32–34 than those during weeks 35–36. Conclusions: These findings might have important implications in preventing preterm birth in Guangzhou as well as other areas with similar weather conditions. Citation: He JR, Liu Y, Xia XY, Ma WJ, Lin HL, Kan HD, Lu JH, Feng Q, Mo WJ, Wang P, Xia HM, Qiu X, Muglia LJ. 2016. Ambient temperature and the risk of preterm birth

  19. High temperature strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); You, Tao (Inventor)

    2011-01-01

    A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500.degree. C. A scanning electron microscopy (SEM) of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity. Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. ITO strain sensors were prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.

  20. High temperature acoustic levitator

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B. (Inventor)

    1984-01-01

    A system is described for acoustically levitating an object within a portion of a chamber that is heated to a high temperature, while a driver at the opposite end of the chamber is maintained at a relatively low temperature. The cold end of the chamber is constructed so it can be telescoped to vary the length (L sub 1) of the cold end portion and therefore of the entire chamber, so that the chamber remains resonant to a normal mode frequency, and so that the pressure at the hot end of the chamber is maximized. The precise length of the chamber at any given time, is maintained at an optimum resonant length by a feedback loop. The feedback loop includes an acoustic pressure sensor at the hot end of the chamber, which delivers its output to a control circuit which controls a motor that varies the length (L) of the chamber to a level where the sensed acoustic pressure is a maximum.

  1. The effect of ambient temperature on diabetes mortality in China: A multi-city time series study.

    PubMed

    Yang, Jun; Yin, Peng; Zhou, Maigeng; Ou, Chun-Quan; Li, Mengmeng; Liu, Yunning; Gao, Jinghong; Chen, Bin; Liu, Jiangmei; Bai, Li; Liu, Qiyong

    2016-02-01

    Few multi-city studies have been conducted to investigate the acute health effects of low and high temperatures on diabetes mortality worldwide. We aimed to examine effects of ambient temperatures on city-/gender-/age-/education-specific diabetes mortality in nine Chinese cities using a two-stage analysis. Distributed lag non-linear model was first applied to estimate the city-specific non-linear and delayed effects of temperatures on diabetes mortality. Pooled effects of temperatures on diabetes mortality were then obtained using meta-analysis, based on restricted maximum likelihood. We found that heat effects were generally acute and followed by a period of mortality displacement, while cold effects could last for over two weeks. The pooled relative risks of extreme high (99th percentile of temperature) and high temperature (90th percentile of temperature) were 1.29 (95%CI: 1.11-1.47) and 1.11 (1.03-1.19) over lag 0-21 days, compared with the 75th percentile of temperature. In contrast, the pooled relative risks over lag 0-21 days were 1.44 (1.25-1.66) for extreme low (1st percentile of temperature) and 1.20 (1.12-1.30) for low temperature (10th percentile of temperature), compared to 25th percentile of temperature. The estimate of heat effects was relatively higher among females than that among males, with opposite trend for cold effects, and the estimates of heat and cold effects were particularly higher among the elderly and those with low education, although the differences between these subgroups were not statistically significant (P>0.05). These findings have important public health implications for protecting diabetes patients from adverse ambient temperatures.

  2. High temperature detonator

    DOEpatents

    Johnson, James O.; Dinegar, Robert H.

    1988-01-01

    A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

  3. High Temperature Superconducting Compounds

    DTIC Science & Technology

    1990-10-01

    usual substrates, SrTiO3 , YSZ, MgO, and LaA103, it has been possible to deposit films on Si substrates without any buffer layer. A bolometer has been...new opportunities for the study of superconductor-insulator transitions and the investigation of photo- doping with carriers of high temperature super... SrTiO3 (00), SrTiO3 (l 10), LaA103 (100), MgO(100), and yttria stabilized zirconia (YSZ). The surfaces of these films could be imaged with a scanning

  4. High temperature geophysical instrumentation

    SciTech Connect

    Hardee, H.C.

    1988-06-01

    The instrumentation development program was to proceed in parallel with scientific research and was driven by the needs of researchers. The development of these instruments has therefore included numerous geophysical field tests, many of which have resulted in the publication of scientific articles. This paper is a brief summary of some of the major geophysical instruments that have been developed and tested under the High Temperature Geophysics Program. These instruments are briefly described and references are given for further detailed information and for scientific papers that have resulted from the use of these instruments. 9 refs., 14 figs.

  5. A high-resolution ambient seismic noise model for Europe

    NASA Astrophysics Data System (ADS)

    Kraft, Toni

    2014-05-01

    measurement precision (i.e. earthquake location), while considering this extremely complex boundary condition. To solve this problem I have developed a high-resolution ambient seismic noise model for Europe. The model is based on land-use data derived from satellite imagery by the EU-project CORINE in a resolution of 100x100m. The the CORINE data consists of several land-use classes, which, besides others, contain: industrial areas, mines, urban fabric, agricultural areas, permanent corps, forests and open spaces. Additionally, open GIS data for highways, and major and minor roads and railway lines were included from the OpenStreetMap project (www.openstreetmap.org). This data was divided into three classes that represent good, intermediate and bad ambient conditions of the corresponding land-use class based on expert judgment. To account for noise propagation away from its source a smoothing operator was applied to individual land-use noise-fields. Finally, the noise-fields were stacked to obtain an European map of ambient noise conditions. A calibration of this map with data of existing seismic stations Europe allowed me to estimate the expected noise level in actual ground motion units for the three ambient noise condition classes of the map. The result is a high-resolution ambient seismic noise map, that allows the network designer to make educated predictions on the expected noise level for arbitrary location in Europe. The ambient noise model was successfully tested in several network optimization projects in Switzerland and surrounding countries and will hopefully be a valuable contribution to improving the data quality of microseismic monitoring networks in Europe.

  6. Effect of Ambient Temperature on Pacing in Soccer depends on Skill Level.

    PubMed

    Link, Daniel; Weber, Hendrik

    2015-05-16

    This study examines the influence ambient temperature has on the distances covered by players in soccer matches. For this purpose, 1211 games from the top German professional leagues were analysed over the course of the seasons 2011/12 and 2012/13 using an optical tracking system. The data shows a) significant differences in the total distance covered (TDC, in m/10 min) between the 1. Bundesliga (M = 1225) and 2. Bundesliga (M = 1201) and b) a significant decrease in TDC from NEUTRAL (-4 to 13° C, M = 1229) to WARM (≥ 14° C, M = 1217) environments. The size of the temperature effect is greater in the 1. Bundesliga (d=.30 vs. d=.16), even though these players presumably have a higher level of fitness. This suggests that better players reduce their exertion level to a greater extent, thus preserving their ability to undertake the high intensity activities when called upon. No reduction in running performance due to COLD (≤ 5° C) temperatures was observed.

  7. Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental Monitoring

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Xu, Jennifer C.; Liu, Chung-Chiun

    2011-01-01

    An ambient temperature oxygen microsensor, based on a Nafion polymer electrolyte, has been developed and was microfabricated using thin-film technologies. A challenge in the operation of Nafion-based sensor systems is that the conductivity of Nafion film depends on the humidity in the film. Nafion film loses conductivity when the moisture content in the film is too low, which can affect sensor operation. The advancement here is the identification of a method to retain the operation of the Nafion films in lower humidity environments. Certain salts can hold water molecules in the Nafion film structure at room temperature. By mixing salts with the Nafion solution, water molecules can be homogeneously distributed in the Nafion film increasing the film s hydration to prevent Nafion film from being dried out in low-humidity environment. The presence of organics provides extra sites in the Nafion film to promote proton (H+) mobility and thus improving Nafion film conductivity and sensor performance. The fabrication of ambient temperature oxygen microsensors includes depositing basic electrodes using noble metals, and metal oxides layer on one of the electrode as a reference electrode. The use of noble metals for electrodes is due to their strong catalytic properties for oxygen reduction. A conducting polymer Nafion, doped with water-retaining components and extra sites facilitating proton movement, was used as the electrolyte material, making the design adequate for low humidity environment applications. The Nafion solution was coated on the electrodes and air-dried. The sensor operates at room temperature in potentiometric mode, which measures voltage differences between working and reference electrodes in different gases. Repeat able responses to 21-percent oxygen in nitrogen were achieved using nitrogen as a baseline gas. Detection of oxygen from 7 to 21 percent has also been demonstrated. The room-temperature oxygen micro sensor developed has extremely low power

  8. High Temperature Protonic Conductors

    NASA Technical Reports Server (NTRS)

    Dynys, Fred; Berger, Marie-Helen; Sayir, Ali

    2007-01-01

    High Temperature Protonic Conductors (HTPC) with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells. Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated. A laser melt modulation (LMM) process was utilized to fabricate bulk samples, while pulsed laser deposition (PLD) was utilized to fabricate thin film membranes . Sr3Ca(1+x)Nb(2-x)O9 and SrCe(1-x)Y(x)O3 bulk samples were fabricated by LMM. Thin film BaCe(0.85)Y(0.15)O3 membranes were fabricated by PLD on porous substrates. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.

  9. Enhanced neuroendocrine response to insulin tolerance test performed under increased ambient temperature.

    PubMed

    Jezová, D; Kvetnanský, R; Nazar, K; Vigas, M

    1998-01-01

    The hypothesis that an increase in ambient temperature modulates neuroendocrine response in clinically used provocative pituitary function tests was verified. Healthy male volunteers were subjected to insulin tolerance tests in two randomized trials. In the first trial hypoglycemia was induced by a bolus injection of insulin (0.1 U per kg of BW, i.v.) at room temperature. In the second trial, the subjects were exposed to increased ambient temperature for 45 min before insulin injection and for 45 min thereafter. The environmental temperature was selected to increase body temperature less than 1C. Under conditions of increased temperature basal hormone levels as measured in antecubital venous blood samples failed to be modified and the hypoglycemia was less severe. Nevertheless, the responses of most (beta-endorphin, ACTH, prolactin, catecholamines), but not all (growth hormone, cortisol), hormones to hypoglycemia were exaggerated. The remarkable increase in ACTH and beta-endorphin release was not accompanied by concomitant increase of plasma cortisol response. The sympathetic-adrenomedullary system was significantly activated, which was manifested particularly by enhanced norepinephrine release. Growth hormone response to hypoglycemia was not modified, while that of prolactin was enhanced. Thus during evaluation of neuroendocrine function under clinical conditions, changes in ambient and body temperature should not be underestimated.

  10. Effect of ambient temperature and light intensity on physiological reactions of heavy broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of ambient temperature, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. The experiment was consisted of a factorial arrangement of treatments in a r...

  11. Sorption Capacity of Europium for Media #1 and Media #2 from Solution at Ambient Temperature

    DOE Data Explorer

    Gary Garland

    2015-03-16

    This dataset shows the capacity for Europium of media #1 and media #2 in a shakertable experiment. The experimental conditions were 150mL of 500ppm Eu solution, 2g of media, pH of 3.2, at ambient temperature.

  12. Improving ethanol production from alfalfa stems via ambient-temperature acid pretreatment and washing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concept of co-production of liquid fuel (ethanol) along with animal feed on farm was proposed. The strategy of using ambient-temperature acid pretreatment, ensiling, and washing to improve ethanol production from alfalfa stems was investigated. Alfalfa stems were separated and pretreated with su...

  13. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. After one year of planning, construction, and the successful drilling of a research well to 495 m b.s.l. the first large scale heat storage test in the Malm aquifer was finished just before Christmas 2014. An enormous technical challenge was the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10-50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye. Injection and production rates were 15 L/s. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes. Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating

  14. Ambient temperature secondary lithium cells containing inorganic electrolyte

    NASA Astrophysics Data System (ADS)

    Schlaikjer, Carl R.

    The history and current status of rechargeable lithium cells using electrolytes based on liquid sulfur dioxide are reviewed. Three separate approaches currently under development include lithium/lithium dithionite/carbon cells with a supporting electrolyte salt; lithium/cupric chloride cells using sulfur dioxide/lithium tetrachloroaluminate; and several adaptations of a lithium/carbon cell using sulfur dioxide/lithium tetrachloroaluminate in which the discharge reaction involves the incorporation of aluminum into the positive electrode. The latter two chemistries have been studied in prototype hardware. For AA size cells with cupric chloride, 157 Whr/1 at 24 W/1 for 230 cycles was reported. For AA size cells containing 2LiCl-CaCl2-4AlCl3-12SO2, energy densities as high as 265 Whr/liter and 100 Whr/kg have been observed, but, at 26 W/1, for only 10 cycles. The advantages and remaining problems are discussed.

  15. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  16. Suicide and Ambient Temperature in East Asian Countries: A Time-Stratified Case-Crossover Analysis

    PubMed Central

    Kim, Yoonhee; Honda, Yasushi; Guo, Yue Leon; Chen, Bing-Yu; Woo, Jong-Min; Ebi, Kristie L.

    2015-01-01

    Background A limited number of studies suggest that ambient temperature contributes to suicide; these studies typically focus on a single nation and use temporally and spatially aggregated data. Objective We evaluated the association between ambient temperature and suicide in multiple cities in three East Asian countries. Methods A time-stratified case-crossover method was used to explore the relationship between temperature and suicide, adjusting for potential time-varying confounders and time-invariant individual characteristics. Sex- and age-specific associations of temperature with suicide were estimated, as were interactions between temperature and these variables. A random-effects meta-analysis was used to estimate country-specific pooled associations of temperature with suicide. Results An increase in temperature corresponding to half of the city-specific standard deviation was positively associated with suicide in most cities, although average suicide rates varied substantially. Pooled country-level effect estimates were 7.8% (95% CI: 5.0, 10.8%) for a 2.3°C increase in ambient temperature in Taiwan, 6.8% (95% CI: 5.4, 8.2%) for a 4.7°C increase in Korea, and 4.5% (95% CI: 3.3, 5.7%) for a 4.2°C increase in Japan. The association between temperature and suicide was significant even after adjusting for sunshine duration; the association between sunshine and suicide was not significant. The associations were greater among men than women in 12 of the 15 cities although not significantly so. There was little evidence of a consistent pattern of associations with age. In general, associations were strongest with temperature on the same day or the previous day, with little evidence of associations with temperature over longer lags (up to 5 days). Conclusions We estimated consistent positive associations between suicide and elevated ambient temperature in three East Asian countries, regardless of country, sex, and age. Citation Kim Y, Kim H, Honda Y, Guo YL

  17. Molecular dynamics of itraconazole at ambient and high pressure.

    PubMed

    Tarnacka, M; Adrjanowicz, K; Kaminska, E; Kaminski, K; Grzybowska, K; Kolodziejczyk, K; Wlodarczyk, P; Hawelek, L; Garbacz, G; Kocot, A; Paluch, M

    2013-12-21

    Comprehensive molecular dynamics studies of vitrified and cryogrounded itraconazole (Itr) were performed at ambient and elevated pressure. DSC measurements yielded besides melting and glass transition observed during heating and cooling of both samples two further endothermic events at around T = 363 K and T = 346 K. The nature of these transitions was investigated using X-ray diffraction, broadband dielectric spectroscopy and Density Functional Theory calculations. The X-ray measurements indicated that extra ordering in itraconazole is likely to occur. Based on calculations and theory derived by Letz et al. the transition observed at T = 363 K was discussed in the context of formation of the nematic mesophase. In fact, additional FTIR measurements revealed that order parameter variation in Itr shows a typical sequence of liquid crystal phases with axially symmetric orientational order; i.e. a nematic phase in the temperature range 361.7 K to 346.5 K and a smectic A phase below 346.5. Moreover, dielectric measurements demonstrated that except for the structural relaxation process, there is also slower mode above the glass transition temperature in both vitrified and cryogrounded samples. We considered the origin of this mode taking into account DFT calculations, rod like shape of itraconazole and distribution of its dipole moment vectors. For the dielectric data collected at elevated pressure, evolution of the steepness index versus pressure was determined. Finally, the pressure coefficient of the glass transition temperature was evaluated to be equal to 190 K GPa(-1).

  18. High temperature interfacial superconductivity

    SciTech Connect

    Bozovic, Ivan; Logvenov, Gennady; Gozar, Adrian Mihai

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.

  19. Enhancing photovoltaic efficiency through radiative cooling of solar cells below ambient temperature

    NASA Astrophysics Data System (ADS)

    Safi, Taqiyyah; Munday, Jeremy

    Sunlight heats up solar cells and the resulting elevated solar cell temperature adversely effects the photovoltaic efficiency and the reliability of the cell. Currently, a variety of active and passive cooling strategies are used to lower the operating temperature of the solar cell. Passive radiative cooling requires no energy input, and is ideal for solar cells; however, previously demonstrated devices still operate above the ambient, leading to a lower efficiency as compared to the ideal Shockley-Queisser limit, which is defined for a cell in contact with an ideal heat sink at ambient temperature (300 K). In this talk, we will describe the use of radiative cooling techniques to lower the cell temperature below the ambient temperature. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that these structures yield an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for cells in an extraterrestrial environment in near-earth orbit.

  20. Effects of ambient room temperature on cold air cooling during laser hair removal.

    PubMed

    Ram, Ramin; Rosenbach, Alan

    2007-09-01

    Forced air cooling is a well-established technique that protects the epidermis during laser heating of deeper structures, thereby allowing for increased laser fluences. The goal of this prospective study was to identify whether an elevation in ambient room temperature influences the efficacy of forced air cooling. Skin surface temperatures were measured on 24 sites (12 subjects) during cold air exposure in examination rooms with ambient temperatures of 72 degrees F (22.2 degrees C) and 82 degrees F (27.8 degrees C), respectively. Before cooling, mean skin surface temperature was 9 degrees F (5 degrees C) higher in the warmer room (P < 0.01). Immediately after exposure to forced air cooling (within 1 s), the skin surface temperature remained considerably higher (10.75 degrees F, or 5.8 degrees C, P < 0.01) in the warmer room. We conclude that forced air cooling in a room with an ambient temperature of 82 degrees F (27.8 degrees C) is not as effective as in a room that is at 72 degrees F (22.2 degrees C).

  1. SHORT VEGETATIVE PHASE Up-Regulates TEMPRANILLO2 Floral Repressor at Low Ambient Temperatures1[OPEN

    PubMed Central

    Marín-González, Esther; Matías-Hernández, Luis; Aguilar-Jaramillo, Andrea E.; Lee, Jeong Hwan; Ahn, Ji Hoon; Suárez-López, Paula; Pelaz, Soraya

    2015-01-01

    Plants integrate day length and ambient temperature to determine the optimal timing for developmental transitions. In Arabidopsis (Arabidopsis thaliana), the floral integrator FLOWERING LOCUS T (FT) and its closest homolog TWIN SISTER OF FT promote flowering in response to their activator CONSTANS under long-day inductive conditions. Low ambient temperature (16°C) delays flowering, even under inductive photoperiods, through repression of FT, revealing the importance of floral repressors acting at low temperatures. Previously, we have reported that the floral repressors TEMPRANILLO (TEM; TEM1 and TEM2) control flowering time through direct regulation of FT at 22°C. Here, we show that tem mutants are less sensitive than the wild type to changes in ambient growth temperature, indicating that TEM genes may play a role in floral repression at 16°C. Moreover, we have found that TEM2 directly represses the expression of FT and TWIN SISTER OF FT at 16°C. In addition, the floral repressor SHORT VEGETATIVE PHASE (SVP) directly regulates TEM2 but not TEM1 expression at 16°C. Flowering time analyses of svp tem mutants indicate that TEM may act in the same genetic pathway as SVP to repress flowering at 22°C but that SVP and TEM are partially independent at 16°C. Thus, TEM2 partially mediates the temperature-dependent function of SVP at low temperatures. Taken together, our results indicate that TEM genes are also able to repress flowering at low ambient temperatures under inductive long-day conditions. PMID:26243615

  2. Hibernation patterns of Turkish hamsters: influence of sex and ambient temperature.

    PubMed

    Batavia, Mariska; Nguyen, George; Harman, Kristine; Zucker, Irving

    2013-02-01

    Turkish hamsters (Mesocricetus brandti) are a model organism for studies of hibernation, yet a detailed account of their torpor characteristics has not been undertaken. This study employed continuous telemetric monitoring of body temperature (T(b)) in hibernating male and female Turkish hamsters at ambient temperatures (T(a)s) of 5 and 13 °C to precisely characterize torpor bout depth, duration, and frequency, as well as rates of entry into and arousal from torpor. Hamsters generated brief intervals of short (<12 h), shallow test bouts (T(b) > 20 °C), followed by deep torpor bouts lasting 4-6 days at T(a) = 5 °C and 2-3 days at T(a) = 13 °C. Females at T(a) = 5 °C had longer bouts than males, but maintained higher torpor T(b); there were no sex differences at T(a) = 13 °C. Neither body mass loss nor food intake differed between the two T(a)s. Hamsters entered torpor primarily during the scotophase (subjective night), but timing of arousals was highly variable. Hamsters at both T (a)s generated short, shallow torpor bouts between deep bouts, suggesting that this species may be capable of both hibernation and daily torpor.

  3. Synthesis of indium nanoparticles at ambient temperature; simultaneous phase transfer and ripening

    NASA Astrophysics Data System (ADS)

    Aghazadeh Meshgi, Mohammad; Kriechbaum, Manfred; Biswas, Subhajit; Holmes, Justin D.; Marschner, Christoph

    2016-12-01

    The synthesis of size-monodispersed indium nanoparticles via an innovative simultaneous phase transfer and ripening method is reported. The formation of nanoparticles occurs in a one-step process instead of well-known two-step phase transfer approaches. The synthesis involves the reduction of InCl3 with LiBH4 at ambient temperature and although the reduction occurs at room temperature, fine indium nanoparticles, with a mean diameter of 6.4 ± 0.4 nm, were obtained directly in non-polar n-dodecane. The direct synthesis of indium nanoparticles in n-dodecane facilitates their fast formation and enhances their size-monodispersity. In addition, the nanoparticles were highly stable for more than 2 months. The nanoparticles were characterised by dynamic light scattering (DLS), small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy to determine their morphology, structure and phase purity.

  4. A systematic review and meta-analysis of ambient temperature and diarrhoeal diseases

    PubMed Central

    Carlton, Elizabeth J; Woster, Andrew P; DeWitt, Peter; Goldstein, Rebecca S; Levy, Karen

    2016-01-01

    Background: Global climate change is expected to increase the risk of diarrhoeal diseases, a leading cause of childhood mortality. However, there is considerable uncertainty about the magnitude of these effects and which populations bear the greatest risks. Methods: We conducted a systematic review using defined search terms across four major databases and, additionally, examined the references of 54 review articles captured by the search. We evaluated sources of heterogeneity by pathogen taxon, exposure measure, study quality, country income level and regional climate, and estimated pooled effect estimates for the subgroups identified in the heterogeneity analysis, using meta-analysis methods. Results: We identified 26 studies with 49 estimates. Pathogen taxa were a source of heterogeneity. There was a positive association between ambient temperature and all-cause diarrhoea (incidence rate ratio (IRR) 1.07; 95% confidence interval (CI) 1.03, 1.10) and bacterial diarrhoea (IRR 1.07; 95% CI 1.04, 1.10), but not viral diarrhoea (IRR 0.96; 95% CI 0.82, 1.11). These associations were observed in low-, middle- and high-income countries. Only one study of protozoan diarrhoea was identified. Conclusions: Changes in temperature due to global climate change can and may already be affecting diarrhoeal disease incidence. The vulnerability of populations may depend, in part, on local pathogen distribution. However, evidence of publication bias and the uneven geographical distribution of studies limit the precision and generalizability of the pooled estimates. PMID:26567313

  5. Investigations into High Temperature Components and Packaging

    SciTech Connect

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  6. Effect of ambient temperature in neonate aspic vipers: growth, locomotor performance and defensive behaviors.

    PubMed

    Aïdam, Aurélie; Michel, Catherine Louise; Bonnet, Xavier

    2013-07-01

    The impact of temperature during incubation and gestation has been tested in various reptiles; the postnatal period has been rarely investigated however. Three groups of newborn aspic vipers (Vipera aspis) were placed under contrasted thermal regimes during 7 months: (1) a cool 23°C constant regime, (2) a warm 28°C constant regime, and (3) an optimal regime with free-access to a wide range of temperatures. Later, all the snakes were placed under hibernation conditions (6°C) during 3 months. Finally all the snakes were placed in the optimal thermal regime during 2 additional months. The total duration of the experiment was of 12 months. Body mass and feeding rates were recorded weekly, body size was measured monthly. We also assessed locomotor performance and recorded several behavioral traits (e.g., defensive and predatory behaviors). As expected, snakes raised under cool temperatures exhibited low feeding rate, growth rate, body condition, and they exhibited poor locomotor performance; they also displayed marked defensive behaviors (e.g., high number of defensive bites) whilst hesitating during longer periods to bite a prey. Such behavioral effects were detected at the end of the experiment (i.e., 5 months after exposure to contrasted thermal treatments [3 months of hibernation plus 2 months of optimal regime]), revealing long term effects. Surprisingly, growth rate and locomotor performance were not different between the two other groups, warm constant 28°C versus optimal regimes (albeit several behavioral traits differed), suggesting that the access to a wide range of ambient temperatures was not a crucial factor.

  7. Screening of agrochemicals in foodstuffs using low-temperature plasma (LTP) ambient ionization mass spectrometry.

    PubMed

    Wiley, Joshua S; García-Reyes, Juan F; Harper, Jason D; Charipar, Nicholas A; Ouyang, Zheng; Cooks, R Graham

    2010-05-01

    Low-temperature plasma (LTP) permits direct ambient ionization and mass analysis of samples in their native environment with minimal or no prior preparation. LTP utilizes dielectric barrier discharges (DBDs) to create a low power plasma which is guided by gas flow onto the sample from which analytes are desorbed and ionized. In this study, the potential of LTP-MS for the detection of pesticide residues in food is demonstrated. Thirteen multi-class agricultural chemicals were studied (ametryn, amitraz, atrazine, buprofezin, DEET, diphenylamine, ethoxyquin, imazalil, isofenphos-methyl, isoproturon, malathion, parathion-ethyl and terbuthylazine). To evaluate the potential of the proposed approach, LTP-MS experiments were performed directly on fruit peels as well as on fruit/vegetable extracts. Most of the agrochemicals examined displayed remarkable sensitivity in the positive ion mode, giving limits of detection (LOD) for the direct measurement in the low picogram range. Tandem mass spectrometry (MS/MS) was used to confirm identification of selected pesticides by using for these experiments spiked fruit/vegetable extracts (QuEChERS, a standard sample treatment protocol) at levels as low as 1 pg, absolute, for some of the analytes. Comparisons of the data obtained by direct LTP-MS were made with the slower but more accurate conventional LC-MS/MS procedure. Herbicides spiked in aqueous solutions were detectable at LODs as low as 0.5 microg L(-1) without the need for any sample preparation. The results demonstrate that ambient LTP-MS can be applied for the detection and confirmation of traces of agrochemicals in actual market-purchased produce and in natural water samples. Quantitative analysis was also performed in a few selected cases and displayed a relatively high degree of linearity over four orders of magnitude.

  8. The monitoring and fatigue behavior of CFCCs at ambient temperature and 1000{degrees}C

    SciTech Connect

    Miriyala, N.; Liaw, P.K.; McHargue, C.J.

    1997-04-01

    Metallographically polished flexure bars of Nicalon/SiC and Nicalon/alumina composites were subjected to monotonic and cycle-fatigue loadings, with loading either parallel or normal to the fabric plies. The fabric orientation did not significantly affect the mechanical behavior of the Nicalon/SiC composite at ambient temperature. However, the mechanical behavior of the Nicalon/alumina composite was significantly affected by the fabric orientation at ambient temperature in air and at 1000{degrees}C in argon atmosphere. In addition, there was a significant degradation in the fatigue performance of the alumina matrix composite at the elevated temperature, owing to creep in the material and degradation in the fiber strength.

  9. Investigation of effective base transit time and current gain modulation of light-emitting transistors under different ambient temperatures

    SciTech Connect

    Yang, Hao-Hsiang; Tu, Wen-Chung; Wang, Hsiao-Lun; Wu, Chao-Hsin

    2014-11-03

    In this report, the modulation of current gain of InGaP/GaAs light-emitting transistors under different ambient temperatures are measured and analyzed using thermionic emission model of quantum well embedded in the transistor base region. Minority carriers captured by quantum wells gain more energy at high temperatures and escape from quantum wells resulting in an increase of current gain and lower optical output, resulting in different I-V characteristics from conventional heterojunction bipolar transistors. The effect of the smaller thermionic lifetime thus reduces the effective base transit time of transistors at high temperatures. The unique current gain enhancement of 27.61% is achieved when operation temperature increase from 28 to 85 °C.

  10. Proliferation of pulmonary artery smooth muscle cells in the development of ascites syndrome in broilers induced by low ambient temperature.

    PubMed

    Wang, J; Qiao, J; Zhao, L H; Li, K; Wang, H; Xu, T; Tian, Y; Gao, M; Wang, X

    2007-12-01

    Pulmonary vascular remodelling, mainly characterized by arterial medial thickening, is an important pathological feature of broiler ascites syndrome (AS). Since vascular smooth muscle cells (VSMC) form the major cellular component of arterial medial layer, we speculate that VSMC proliferation is one of the causes of pulmonary arterial medial thickening in ascitic broilers. Hence, the present study was designed to investigate the role of VSMC proliferation in pulmonary vascular remodelling in development of AS induced by low ambient temperature. Broilers in control group (22 +/- 1.5 degrees C) and low temperature group (11 +/- 2 degrees C) were sampled every week at 15-50 days of age. Proliferative indexes of VSMC in pulmonary arteries were assessed with proliferating cell nuclear antigen, and the relative medial thickness (RMT) and relative wall area (RWA), as indexes of pulmonary vascular remodelling, were examined by computer-image analysing system. The results showed that the high incidence (18.75%) of AS was induced by low temperature, and a significantly increased VSMC proliferation was observed in pulmonary arteries in the low temperature group at 22-50 days of age (P < 0.05). In addition, RMT and RWA in pulmonary arteries were significantly elevated in the low temperature group from 36 days of age (P < 0.05), indicating that pulmonary vascular remodelling occurred following VSMC proliferation in AS. Our data suggest that proliferation of VSMC may facilitate pulmonary vascular remodelling and have a pivotal role in AS induced by low ambient temperature.

  11. The association between ambient temperature and children's lung function in Baotou, China

    NASA Astrophysics Data System (ADS)

    Li, Shanshan; Guo, Yuming; Williams, Gail; Baker, Peter; Ye, Xiaofang; Madaniyazi, Lina; Kim, Dae-Seon; Pan, Xiaochuan

    2015-07-01

    The objective of this study is to examine the association between ambient temperature and children's lung function in Baotou, China. We recruited 315 children (8-12 years) from Baotou, China in the spring of 2004, 2005, and 2006. They performed three successive forced expiratory measurements three times daily (morning, noon, and evening) for about 5 weeks. The highest peak expiratory flow (PEF) was recorded for each session. Daily data on ambient temperature, relative humidity, and air pollution were monitored during the same period. Mixed models with a distributed lag structure were used to examine the effects of temperature on lung function while adjusting for individual characteristics and environmental factors. Low temperatures were significantly associated with decreases in PEF. The effects lasted for lag 0-2 days. For all participants, the cumulative effect estimates (lag 0-2 days) were -1.44 (-1.93, -0.94) L/min, -1.39 (-1.92, -0.86) L/min, -1.40 (-1.97, -0.82) L/min, and -1.28 (-1.69, -0.88) L/min for morning, noon, evening, and daily mean PEF, respectively, associated with 1 °C decrease in daily mean temperature. Generally, the effects of temperature were slightly stronger in boys than in girls for noon, evening, and daily mean PEF, while the effects were stronger in girls for morning PEF. PM2.5 had joint effects with temperature on children's PEF. Higher PM2.5 increased the impacts of low temperature. Low ambient temperatures are associated with lower lung function in children in Baotou, China. Preventive health policies will be required for protecting children from the cold weather.

  12. Ambient Temperature and Stroke Occurrence: A Systematic Review and Meta-Analysis

    PubMed Central

    Wang, Xia; Cao, Yongjun; Hong, Daqing; Zheng, Danni; Richtering, Sarah; Sandset, Else Charlotte; Leong, Tzen Hugh; Arima, Hisatomi; Islam, Shariful; Salam, Abdul; Anderson, Craig; Robinson, Thompson; Hackett, Maree L.

    2016-01-01

    Biologically plausible associations exist between climatic conditions and stroke risk, but study results are inconsistent. We aimed to summarize current evidence on ambient temperature and overall stroke occurrence, and by age, sex, and variation of temperature. We performed a systematic literature search across MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 16 October 2015 to identify all population-based observational studies. Where possible, data were pooled for meta-analysis with Odds ratios (OR) and corresponding 95% confidence intervals (CI) by means of the random effects meta-analysis. We included 21 studies with a total of 476,511 patients. The data were varied as indicated by significant heterogeneity across studies for both ischemic stroke (IS) and intracerebral hemorrhage (ICH). Pooled OR (95% CI) in every 1 degree Celsius increase in ambient temperature was significant for ICH 0.97 (0.94–1.00), but not for IS 1.00 (0.99–1.01) and subarachnoid hemorrhage (SAH) 1.00 (0.98–1.01). Meta-analysis was not possible for the pre-specified subgroup analyses by age, sex, and variation of temperature. Change in temperature over the previous 24 h appeared to be more important than absolute temperature in relation to the risk of stroke, especially in relation to the risk of ICH. Older age appeared to increase vulnerability to low temperature for both IS and ICH. To conclude, this review shows that lower mean ambient temperature is significantly associated with the risk of ICH, but not with IS and SAH. Larger temperature changes were associated with higher stroke rates in the elderly. PMID:27420077

  13. High temperature energy harvester for wireless sensors

    NASA Astrophysics Data System (ADS)

    Köhler, J. E.; Heijl, R.; Staaf, L. G. H.; Zenkic, S.; Svenman, E.; Lindblom, A.; Palmqvist, A. E. C.; Enoksson, P.

    2014-09-01

    Implementing energy harvesters and wireless sensors in jet engines will simplify development and decrease costs by reducing the need for cables. Such a device could include a small thermoelectric generator placed in the cooling channels of the jet engine where the temperature is between 500-900 °C. This paper covers the synthesis of suitable thermoelectric materials, design of module and proof of concept tests of a thermoelectric module. The materials and other design variables were chosen based on an analytic model and numerical analysis. The module was optimized for 600-800 °C with the thermoelectric materials n-type Ba8Ga16Ge30 and p-type La-doped Yb14MnSb11, both with among the highest reported figure-of-merit values, zT, for bulk materials in this region. The materials were synthesized and their structures confirmed by x-ray diffraction. Proof of concept modules containing only two thermoelectric legs were built and tested at high temperatures and under high temperature gradients. The modules were designed to survive an ambient temperature gradient of up to 200 °C. The first measurements at low temperature showed that the thermoelectric legs could withstand a temperature gradient of 123 °C and still be functional. The high temperature measurement with 800 °C on the hot side showed that the module remained functional at this temperature.

  14. High Temperature Superconducting Materials Database

    National Institute of Standards and Technology Data Gateway

    SRD 149 NIST High Temperature Superconducting Materials Database (Web, free access)   The NIST High Temperature Superconducting Materials Database (WebHTS) provides evaluated thermal, mechanical, and superconducting property data for oxides and other nonconventional superconductors.

  15. High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

    2002-01-01

    It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

  16. Thermoregulatory consequences of long-term microwave exposure at controlled ambient temperatures. Final report

    SciTech Connect

    Adair, E.R.; Spiers, D.E.; Rawson, R.O.; Adams, B.W.; Sheldon, D.K.

    1984-08-01

    The study was designed to identify and measure changes in thermoregulatory response systems, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz CW microwaves 40 hours/week for 15 weeks. Microwave power densities explored were 1 and 5 mW/sq. cm. (SAR = 0.16 W/kg per mW/sq. cm.) and were presented at controlled environmental temperatures of 25, 30, and 35 C. Standardized tests, conducted periodically, assessed changes in thermoregulatory responses. Dependent variables measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no alteration of metabolic rate, internal body temperature, or thermoregulatory behavior by microwave exposure although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 C environment, not enhanced significantly by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass which appeared to be a function of microwave power density.

  17. Effect of 3,4-methylenedioxymethamphetamine ("ecstasy") on body temperature and liver antioxidant status in mice: influence of ambient temperature.

    PubMed

    Carvalho, Márcia; Carvalho, Félix; Remião, Fernando; de Lourdes Pereira, Maria; Pires-das-Neves, Ricardo; de Lourdes Bastos, Maria

    2002-04-01

    The consumption of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) is known to cause severe hyperthermia and liver damage in humans. The thermogenic response induced by MDMA is complex and partially determined by the prevailing ambient temperature (AT). This is of extreme importance since ecstasy is often consumed at "rave" parties, where dancing takes place in a warm environment, which may exacerbate the effect of MDMA on thermoregulation. In view of the fact that hyperthermia is a well-known pro-oxidant aggressive condition, its potential role in ecstasy-induced hepatocellular toxicity should be further studied. Thus, the present study was performed in order to evaluate the influence of AT on the effects of single administration of MDMA on body temperature and liver toxicity in Charles River mice. Animals were given an acute intraperitoneal dose of MDMA (5, 10 or 20 mg/kg) and placed in AT of 20+/-2 degrees C or 30+/-2 degrees C for 24 h. Body temperature was measured during the study using implanted transponders and a temperature probe reading device. Plasma and liver samples were used for biochemical analysis. Liver sections were also taken for histological examination. The parameters evaluated were (1) plasma levels of transaminases and alkaline phosphatase, (2) hepatic glutathione (GSH), (3) hepatic lipid peroxidation, (4) activity of hepatic antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, glutathione- S-transferase, copper/zinc superoxide dismutase and manganese superoxide dismutase), and (5) liver histology. The hyperthermic response elicited by MDMA was clearly dose-related and potentiated by high AT. Administration of MDMA produced some evidence of oxidative stress, expressed as GSH depletion at both ATs studied, as well as by lipid peroxidation and decreased catalase activity at high AT. High AT, by itself, decreased glutathione peroxidase activity. Histological examination of the liver revealed abnormalities of a dose

  18. Direct Transformation of Amorphous Silicon Carbide into Graphene under Low Temperature and Ambient Pressure

    PubMed Central

    Peng, Tao; Lv, Haifeng; He, Daping; Pan, Mu; Mu, Shichun

    2013-01-01

    A large-scale availability of the graphene is critical to the successful application of graphene-based electronic devices. The growth of epitaxial graphene (EG) on insulating silicon carbide (SiC) surfaces has opened a new promising route for large-scale high-quality graphene production. However, two key obstacles to epitaxial growth are extremely high requirements for almost perfectly ordered crystal SiC and harsh process conditions. Here, we report that the amorphous SiC (a-Si1−xCx) nano-shell (nano-film) can be directly transformed into graphene by using chlorination method under very mild reaction conditions of relative low temperature (800°C) and the ambient pressure in chlorine (Cl2) atmosphere. Therefore, our finding, the direct transformation of a-Si1−xCx into graphene under much milder condition, will open a door to apply this new method to the large-scale production of graphene at low costs. PMID:23359349

  19. Analyzing the impact of ambient temperature indicators on transformer life in different regions of Chinese mainland.

    PubMed

    Bai, Cui-fen; Gao, Wen-Sheng; Liu, Tong

    2013-01-01

    Regression analysis is applied to quantitatively analyze the impact of different ambient temperature characteristics on the transformer life at different locations of Chinese mainland. 200 typical locations in Chinese mainland are selected for the study. They are specially divided into six regions so that the subsequent analysis can be done in a regional context. For each region, the local historical ambient temperature and load data are provided as inputs variables of the life consumption model in IEEE Std. C57.91-1995 to estimate the transformer life at every location. Five ambient temperature indicators related to the transformer life are involved into the partial least squares regression to describe their impact on the transformer life. According to a contribution measurement criterion of partial least squares regression, three indicators are conclusively found to be the most important factors influencing the transformer life, and an explicit expression is provided to describe the relationship between the indicators and the transformer life for every region. The analysis result is applicable to the area where the temperature characteristics are similar to Chinese mainland, and the expressions obtained can be applied to the other locations that are not included in this paper if these three indicators are known.

  20. Influence of Ambient Temperature and Confinement on the Chemical Immobilization of Fallow Deer ( Dama dama ).

    PubMed

    Costa, Giovanna Lucrezia; Nastasi, Bernadette; Musicò, Marcello; Spadola, Filippo; Morici, Manuel; Cucinotta, Giuseppe; Interlandi, Claudia

    2017-04-01

    We used physiological parameters and the duration and quality of anesthesia to compare the effects of two ambient temperatures and of the duration of pre-immobilization confinement on the chemical immobilization of fallow deer. We divided 45 free-ranging fallow deer ( Dama dama ) into two groups: Group A were deer captured in winter (average 12 C), using 1 mg/kg of xylazine and 1 mg/kg of tiletamine-zolazepam; and Group B were deer captured in spring (average 24 C), using 2 mg/kg of xylazine and 1.5 mg/kg of tiletamine-zolazepam, after being confined in a pen. We observed lower mean respiratory rate and oxygen saturation in Group B. In contrast, the mean body temperature and the mean blood lactate concentration were significantly higher in Group B, and quality of anesthesia was better in Group A. Mean induction time (time to achieve recumbency) and durations of recumbency were the same in Groups A and B: approximately 8 and 50 min, respectively. Despite the lower drug dosage, better sedation was obtained in Group A than in group B. The time of year, most likely associated with differences in ambient temperature and in confinement, influenced the recommended dosage for xylazine and tiletamine-zolazepam in fallow deer. As all the animals were sound, we concluded that the only factors that influenced the outcome of the present study were the ambient temperature and the level of stress caused by confinement in the pen.

  1. Imidapril inhibits right ventricular remodeling induced by low ambient temperature in broiler chickens.

    PubMed

    Hao, Xue-Qin; Zhang, Shou-Yan; Cheng, Xiang-Chao; Li, Meng; Sun, Tong-Wen; Zhang, Ji-Liang; Guo, Wen; Li, Li

    2013-06-01

    This study explored the effect of imidapril on the right ventricular remodeling induced by low ambient temperature in broiler chickens. Twenty-four broiler chickens were randomly divided into 3 groups (n = 8), including the control group, low temperature group, and imidapril group. Chickens in the control group were raised at normal temperature, whereas chickens in the low temperature group and imidapril group were exposed to low ambient temperature (12 to 18°C) from 14 d of age until 45 d of age. At the same time, chickens in the imidapril group were gavaged with imidapril at 3 mg/kg once daily for 30 d. The thickness of the right ventricular wall was observed with echocardiography. The BW and wet lung weight as well as weight of right and left ventricles and ventricular septum were measured. Both wet lung weight index and right ventricular hypertrophy index were calculated. Pulmonary arterial systolic pressure was assessed according to echocardiography. The expression of ACE and ACE2 mRNA in the right ventricular myocardial tissue was quantified by real-time PCR. Proliferating cell nuclear antigen-positive cells were detected by immunohistostaining. The concentration of angiotensin (Ang) II and Ang (1-7) in the right ventricular myocardial tissue was measured with ELISA. The results showed that right ventricular hypertrophy index, wet lung weight index, pulmonary arterial systolic pressure, expression of ACE mRNA in the right ventricular tissue, Ang II concentration, and the thickness of the right ventricular wall in the low temperature group increased significantly compared with those in the control group and imidapril group. The ACE2 mRNA expression increased 36%, whereas Ang (1-7) concentration decreased significantly in the low temperature group compared with that in the control group and imidapril group. In conclusion, imidapril inhibits right ventricular remodeling induced by low ambient temperature in broiler chickens.

  2. Depicting the Dependency of Isoprene in Ambient Air and from Plants on Temperature and Solar Radiation by Using Regression Analysis

    NASA Astrophysics Data System (ADS)

    Saxena, Pallavi; Ghosh, Chirashree

    2016-07-01

    Among all sources of volatile organic compounds, isoprene emission from plants is an important part of the atmospheric hydrocarbon budget. In the present study, isoprene emission capacity at the bottom of the canopies of plant species viz. Dalbergia sissoo and Nerium oleander and in ambient air at different sites selected on the basis of land use pattern viz. near to traffic intersection with dense vegetation, away from traffic intersection with dense vegetation under floodplain area (Site I) and away from traffic intersection with dense vegetation under hilly ridge area (Site II) during three different seasons (monsoon, winter and summer) in Delhi were measured. In order to find out the dependence of isoprene emission rate on temperature and solar radiation, regression analysis has been performed. In case of dependency of isoprene in ambient air on temperature and solar radiation in selected seasons it has been found that high isoprene was found during summer season as compared to winter and monsoon seasons. Thus, positive linear relationship gives the best fit between temperature, solar rdaiation and isoprene during summer season as compared to winter and monsoon season. On the other hand, in case of isoprene emission from selected plant species, it has been found that high temperature and solar radiation promotes high isoprene emission rates during summer season as compared to winter and monsoon seasons in D. sissoo. Thus, positive linear relationship gives the best fit between temperature, solar radiation and isoprene emission rate during summer season as compared to winter and monsoon season. In contrast, in case of Nerium oleander, no such appropriate relationship was obtained. The study concludes that in ambient air, isoprene concentration was found to be high during summer season as compared to other seasons and gives best fit between temperature, solar radiation and isoprene. In case of plants, Dalbergia sissoo comes under high isoprene emission category

  3. Evaluation of Aluminum Alloy 2050-T84 Microstructure Mechanical Properties at Ambient and Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Hafley, Robert A.; Domack, Marcia S.; Hales, Stephen J.; Shenoy, Ravi N.

    2011-01-01

    Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of the incumbent aluminum alloy, 2195, which will enable the designs with greater structural efficiency. While ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and fracture tests were conducted on 4 inch thick 2050-T84 plate at ambient temperature and at -320 F. Various metallurgical analyses were also performed in order to provide an understanding of the compositional homogeneity and microstructure of 2050.

  4. Evaluation of Aluminum Alloy 2050-T84 Microstructure and Mechanical Properties at Ambient and Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Hafley, Robert A.; Domack, Marcia S.; Hales, Stephen J.; Shenoy, Ravi N.

    2011-01-01

    Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of the incumbent aluminum alloy, 2195, which will enable designs with greater structural efficiency. While ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and fracture tests were conducted on 4 inch thick 2050-T84 plate at ambient temperature and at -320degF. Various metallurgical analyses were also performed in order to provide an understanding of the compositional homogeneity and microstructure of 2050.

  5. Time relationship between ambient temperature change and antigen stimulation on immune responses of mice

    NASA Astrophysics Data System (ADS)

    Hayashi, O.; Kikuchi, M.

    1989-03-01

    We investigated the time relationship between ambient temperature change and antigen stimulation on immune responses to sheep red blood cells (SRBC) and polyvinylpyrrolidone (PVP) in mice. In the case of a shift from comfortable (25°C) to cold (8°C) temperatures, suppression in the number of splenic plaque-forming cells (PFC) took place mainly when the shift was done between 1 day before and 2 to 4 days after immunization. The suppression of the PVP response lasted for up to a maximum of 6 days when mice were transferred 1 day before immunization. In the case of a temperature shift from 25° to 36.5°C, the suppressive effect was found when the temperature shift was done between 4 days before and 2 days after immunization. The effect lasted longer than that of the temperature shift to cold, i.e., at least 9 days after the temperature shift. Blood corticosterone levels after the temperature shifts corresponded to changes in the immune responses: elevation of the blood corticosterone levels was observed for only the first 3 days after a temperature shift to 8°C but for 10 days after a temperature shift to 36.5°C during the period time of the experiment. These result suggested that blood corticosterone level contributes to the duration of the effects of temperature shifts on immune responses of mice. Furthermore, it appeared that the early stage of the immune response is more susceptible to temperature shifts than the later stage. To explain these results, the terms “effective period” in the course of physiological adaptation to changed ambient temperature and “susceptible period” in the course of the immune response, were proposed.

  6. Development of integrated thermionic circuits for high-temperature applications

    NASA Technical Reports Server (NTRS)

    Mccormick, J. B.; Wilde, D.; Depp, S.; Hamilton, D. J.; Kerwin, W.; Derouin, C.; Roybal, L.; Wooley, R.

    1981-01-01

    Integrated thermionic circuits (ITC) capable of extended operation in ambient temperatures up to 500 C are studied. A set of practical design and performance equations is demonstrated. Experimental results are discussed in which both devices and simple circuits were successfully operated in 5000 C environments for extended periods. It is suggested that ITC's may become an important technology for high temperature instrumentation and control systems in geothermal and other high temperature environments.

  7. Thermal degradation of concrete in the temperature range from ambient to 315{degrees}C (600{degrees}F)

    SciTech Connect

    Kassir, M.K.; Bandyopadhyay, K.K.; Reich, M.

    1993-06-01

    This report is concerned with determining the effect of elevated temperatures on the behavior of concrete. Emphasis is placed on quantifying the degree of potential degradation of the physical properties of concrete in high-level waste storage tanks. The range in the temperature elevation of interest covers from ambient to 315{degrees}C (600{degrees}F). The literature has been reviewed to examine the applicable experimental data and quantify the degradation in the concrete and reinforcing steel. Since many variables and test conditions control the results in the data base, upper and lower bounds of the degraded properties at temperatures applicable to the environments of the storage tanks are summarized and presented in explicit forms. Such results are useful in assessing the effect of elevated temperatures on the structural behavior of the tanks. Also, they provide the technical basis for a parametric study that may be necessary to investigate the thermal aspects of the structural integrity of the tanks.

  8. High temperature nanoplasmonics

    NASA Astrophysics Data System (ADS)

    Alabastri, Alessandro; Toma, Andrea; Malerba, Mario; De Angelis, Francesco; Proietti Zaccaria, Remo

    2016-09-01

    Metallic nanostructures can be utilized as heat nano-sources which can find application in different areas such as photocatalysis, nanochemistry or sensor devices. Here we show how the optical response of plasmonic structures is affected by the increase of temperature. In particular we apply a temperature dependent dielectric function model to different nanoparticles finding that the optical responses are strongly dependent on shape and aspect-ratio. The idea is that when metallic structures interact with an electromagnetic field they heat up due to Joule effect. The corresponding temperature increase modifies the optical response of the particle and thus the heating process. The key finding is that, depending on the structures geometry, absorption efficiency can either increase or decrease with temperature. Since absorption relates to thermal energy dissipation and thus to temperature increase, the mechanism leads to positive or negative loops. Consequently, not only an error would be made by neglecting temperature but it would be not even possible to know, a priori, if the error is towards higher or lower values.

  9. Psychophysics of a Nociceptive Test in the Mouse: Ambient Temperature as a Key Factor for Variation

    PubMed Central

    Pincedé, Ivanne; Pollin, Bernard; Meert, Theo; Plaghki, Léon; Le Bars, Daniel

    2012-01-01

    Background The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. Methodology/Principal Findings Basically, the procedures involved heating of the tail with a CO2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. Conclusions/Significance We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as “pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of mice. PMID:22629325

  10. Estrous cycle fluctuations in sex and ingestive behavior are accentuated by exercise or cold ambient temperatures.

    PubMed

    Abdulhay, Amir; Benton, Noah A; Klingerman, Candice M; Krishnamoorthy, Kaila; Brozek, Jeremy M; Schneider, Jill E

    2014-06-01

    This article is part of a Special Issue "Energy Balance". In female Syrian hamsters (Mesocricetus auratus), low circulating levels of ovarian steroids are associated with increased food hoarding and decreased sexual motivation, but these effects are exaggerated in food-restricted females. To determine whether cold ambient temperature has the same effects as food restriction, groups of hamsters were fed ad libitum while they were housed at either 5 °C or 22 °C, and then tested for behavior for 90 min on each day of the estrous cycle. In females housed at 22 °C, high levels of sexual motivation and low levels of food hoarding were seen every day of the estrous cycle. In females housed at 5 °C, high levels of sexual motivation were restricted to the periovulatory day. On the three nonestrous days, these females showed high levels of food hoarding, but not food intake. A separate cohort of females were provided with access to running wheels and housed at 22 °C. They showed high levels of sexual motivation restricted to the periovulatory day, similar to the pattern of sexual motivation seen in cold-housed females. Unlike cold-housed females, those with running wheels showed low levels of food hoarding and high levels of food intake. Food restriction, cold housing, and access to wheels had no significant effect on plasma estradiol or progesterone concentrations, but significantly decreased plasma leptin concentrations. All three energetic challenges unmask estrous cycle fluctuations in sexual motivation that are obscured in laboratory conditions, i.e., isolation in a small cage with an overabundance of food.

  11. Modulation of ozone toxicity with changes in ambient temperature in the unanesthetized, unrestrained rat

    SciTech Connect

    Watkinson, W.P.; Wiester, M.J. )

    1991-03-15

    Previous studies from this laboratory have demonstrated an attenuating effect of moderate decreases in body core temperature (T{sub co}) on the toxic response to xenobiotic agents. This study examined an additional modulating effect induced by changes in ambient temperature (T{sub a}). Male Fischer 344 rats were implanted with radiometry transmitters that permitted continuous monitoring of T{sub co}, activity, and electrocardiogram (ECG); heart rate (HR) was derived from the ECG signal. Animals were divided into nine treatment groups and continuously exposed to one of three concentrations of O{sub 3} for 48 hrs while maintained at one of three T{sub a}'s. O{sub 3} exposure led to hypothermia and bradycardia at all three T{sub a}'s. Decreases in T{sub co} and HR ranged from 1.5C and 75 bpm in the high T{sub a} group to 6.1C and 250 bpm in the low T{sub a} group. The only lethalities occurred in the high O{sub 3}-low T{sub a} group. Following O{sub 3} exposure, rats were anesthetized with urethane, intubated, and their lungs were lavaged with warm saline. The number of cells/ml in lavage fluid increased proportionally with decreases in T{sub a} and increases in O{sub 3} concentration. Cellular debris and the ratio of white cells/alveolar macrophages increased with increases in O{sub 3}. These results demonstrate the profound impact of T{sub a} on T{sub co} and the subsequent toxic response in the conscious, unrestrained rat exposed to O{sub 3}.

  12. Dynamical prediction of flu seasonality driven by ambient temperature: influenza vs. common cold

    NASA Astrophysics Data System (ADS)

    Postnikov, Eugene B.

    2016-01-01

    This work presents a comparative analysis of Influenzanet data for influenza itself and common cold in the Netherlands during the last 5 years, from the point of view of modelling by linearised SIRS equations parametrically driven by the ambient temperature. It is argued that this approach allows for the forecast of common cold, but not of influenza in a strict sense. The difference in their kinetic models is discussed with reference to the clinical background.

  13. Ambient temperature and air pressure modulate hormones and behaviour in Greylag geese (Anser anser) and Northern bald ibis (Geronticus eremita).

    PubMed

    Dorn, Sebastian; Wascher, Claudia A F; Möstl, Erich; Kotrschal, Kurt

    2014-10-01

    Ambient temperature and air pressure are relevant stimuli that can elicit hormonal responses in alignment with adjusting individuals' physiology and behaviour. This study investigated possible changes in corticosterone (C) and testosterone (T) and contingencies with behaviour in response to ambient temperature and air pressure, and it evaluated the temporal response dynamics of these hormones in 12 individual Greylag geese (Anser anser) over 26 and 12 individual Northern bald ibis (Geronticus eremita) over 27 days, during late winter. Immunoreactive metabolites of C and T were analysed non-invasively from 626 fecal samples by means of group-specific antibodies and correlated to behaviour and weather factors. In both species, high C levels correlated with low temperatures 24h before sampling, but low C levels correlated with high air pressure 6-12h before sampling. In both species, C levels and behavioural activity were negatively correlated. In addition, temperature had a positive influence on T levels in both species 12-24h before sampling. The fact that weather conditions influenced changes in levels of C, while social interactions did not, is indicative of a general mechanism of graduated physiological adjustment to environmental variations affecting metabolism, stress responses and behaviour.

  14. Catalytic oxidation of low-concentration CO at ambient temperature over supported Pd-Cu catalysts.

    PubMed

    Wang, Fagen; Zhang, Haojie; He, Dannong

    2014-01-01

    The CO catalytic oxidation at ambient temperature and high space velocity was studied over the Pd-Cu/MOx (MOx = TiO2 and AI203) catalysts. The higher Brunauer-Emmett-Teller area surface of the A1203 support facilitates the dispersion of Pd2+ species, and the presence of Cu2Cl(OH)3 accelerates the re-oxidation of Pd0 to Pd2+ over the Pd-Cu/Al203 catalyst, which contributed to better performance of CO catalytic oxidation. The poorer activity of the Pd-Cu/TiO2 catalyst was attributed to the lower dispersion of Pd2+ species because of the less surface area and the non-formation of Cu2CI(OH)3 species. The presence of saturated moisture showed a negative effect on CO conversion over the two catalysts. This might be because of the competitive adsorption, the formation of carbonate species and the transformation of Cu2CI(OH)3 to inactive CuCI over the Pd-Cu/AI2O3 catalyst, which facilitates the aggregation of PdO species over the Pd-Cu/TiO2 catalyst under the moisture condition.

  15. Synthesis and pillaring of a layered vanadium oxide from V 2O 5 at ambient temperature

    NASA Astrophysics Data System (ADS)

    Cheng, Soofin; Hwang, Hong-Da; Maciel, Gary E.

    1998-10-01

    The synthesis and structural characterization of an amine-intercalated layered vanadium oxide and its silica-pillared derivative are described. The amine-intercalated vanadium oxide was prepared by reacting V 2O 5 with a mixture of alkylamine and a small amount of water at ambient temperature. The layer structure was examined by means of various analytical techniques, such as X-ray powder diffraction, thermal analysis, IR, UV-Vis and NMR spectroscopy, as well as elemental analysis. The alkylammonium ion-formed bilayers in the interlayer were ion-exchangeable with alkali ions. Moreover, ESR spectra showed that vanadium retained pentavalence through the intercalation reaction, although a small portion of vanadium was found to be reduced after the compound was stored in air for longer than 24 h. By reacting the amine-intercalated layer vanadia with a solution of tetraethyl orthosilicate, amine and acetone, followed by calcination, a silica-pillared derivative of microporous structure and high surface area was obtained.

  16. Effect of ambient temperature on phenotype and functions of professional phagocytes of athymic nude mice.

    PubMed

    Vetvicka, V; Holub, M; Houstek, J

    1993-02-01

    Cytofluorometric analysis of surface marker expression was performed on myeloid cells isolated from bone marrow, spleen and lymph nodes of nude mice and nu/+ and +/+ mice (haired controls) exposed for various time periods to ambient temperature of 22 degrees C or 28 degrees C. A rise in the proportion of cells bearing macrophage markers (MAC-1, MAC-3 and F4/80) in the spleen and of FcR+ cells in all tissues tested was found in 22 degrees C-exposed nudes with high nonshivering thermogenesis. Numbers of MAC-1+ macrophages and actively phagocytic cells increased also in peritoneal exudates. There was a conspicuous predominance of large macrophages in the exudates and the specific markers decreased in density on their surface. Ia expression declined in all tissues tested with the length of exposure to cold. In the granulocytic series (BP-2+ cells), there was a decrease in the bone marrow and lymph nodes and an increase in the spleen and circulation, which suggested an enhanced mobilization and increased production at extramedullary sites in cold-exposed nude mice. The changes in haired mice were negligible.

  17. Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

    NASA Astrophysics Data System (ADS)

    Warid Wazien, A. Z.; Bakri Abdullah, Mohd Mustafa Al; Abd. Razak, Rafiza; Mohd Remy Rozainy, M. A. Z.; Faheem Mohd Tahir, Muhammad

    2016-06-01

    Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

  18. Ambient maximum temperature as a function of Salmonella food poisoning cases in the Republic of Macedonia

    PubMed Central

    Kendrovski, Vladimir; Karadzovski, Zarko; Spasenovska, Margarita

    2011-01-01

    Background: Higher temperatures have been associated with higher salmonellosis notifications worldwide. Aims: The objective of this paper is to assess the seasonal pattern of Salmonella cases among humans. Material and Methods: The relationship between ambient maximum temperature and reports of confirmed cases of Salmonella in the Republic of Macedonia and Skopje during the summer months (i.e. June, July, August and September) beginning in 1998 through 2008 was investigated. The monthly number of reported Salmonella cases and ambient maximum temperatures for Skopje were related to the national number of cases and temperatures recorded during the same timeframe using regression statistical analyses. The Poisson regression model was adapted for the analysis of the data. Results: While a decreasing tendency was registered at the national level, the analysis for Skopje showed an increasing tendency for registration of new salmonella cases. Reported incidents of salmonellosis, were positively associated (P<0.05) with temperature during the summer months. By increasing of the maximum monthly mean temperature of 1° C in Skopje, the salmonellosis incidence increased by 5.2% per month. Conclusions: The incidence of Salmonella cases in the Macedonian population varies seasonally: the highest values of the Seasonal Index for Salmonella cases were registered in the summer months, i.e. June, July, August and September. PMID:22540096

  19. The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia) under ambient and elevated ocean temperatures.

    PubMed

    Horwitz, Rael; Jackson, Matthew D; Mills, Suzanne C

    2017-01-01

    Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species' life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient) and predicted end-of-century elevated ocean temperatures (+3 °C). Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality.

  20. The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia) under ambient and elevated ocean temperatures

    PubMed Central

    Jackson, Matthew D.; Mills, Suzanne C.

    2017-01-01

    Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species’ life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient) and predicted end-of-century elevated ocean temperatures (+3 °C). Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality. PMID:28168118

  1. High temperature lubricating process

    DOEpatents

    Taylor, R.W.; Shell, T.E.

    1979-10-04

    It has been difficult to provide adequate lubrication for load bearing, engine components when such engines are operating in excess of about 475/sup 0/C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface, such as in an engine being operated at temperatures in excess of about 475/sup 0/C. The process comprises contacting and maintaining the following steps: a gas phase is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant; the gas phase is contacted with the load bearing surface; the load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant; and the solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

  2. High temperature lubricating process

    DOEpatents

    Taylor, Robert W.; Shell, Thomas E.

    1982-01-01

    It has been difficult to provide adaquate lubrication for load bearing, engine components when such engines are operating in excess of about 475.degree. C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface (14), such as in an engine (10) being operated at temperatures in excess of about 475.degree. C. The process comprises contacting and maintaining steps. A gas phase (42) is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant. The gas phase is contacted with the load bearing surface. The load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant. The solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

  3. Improvements on APTC (Ambient Pressure Thermal Cycling) Chamber Regarding Temperature Homogeneity and Energy Consumption

    NASA Astrophysics Data System (ADS)

    Sollner, B.; Doring, D.

    2014-06-01

    This paper describes the working principles of IABG's Ambient Pressure Thermal Cycling chamber (an alternative to thermal-vacuum tests for some cases) and our activities to characterize and improve the system. For example a 3D grid of 64 temperature sensors was installed inside the test volume, in order to determine reliable temperature distribution data for standard operating conditions. Camera monitoring inside the temperature control / fan box allowed us to study the processes. A modification of the direct injection of liquid nitrogen (for efficient cooling) by installation of defined spray nozzles improved the temperature distribution. The characteristics of the original LN2 injection valve caused enormous consumption of liquid nitrogen and electrical power even at constant chamber temperatures. A new valve with a different control characteristic reduced this standby consumption remarkably.

  4. High-temperature piezoelectric sensing.

    PubMed

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2013-12-20

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  5. High-Temperature Piezoelectric Sensing

    PubMed Central

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  6. High Temperature Superconducting Compounds

    DTIC Science & Technology

    1992-11-30

    power spectral density measurements as a function of temperature, frequency, current, and magnetic field on DyBa2Cu3O7.x ( DBCO ) thin films have been...proceeding. The goals has been to understand the "intrinsic" noise present in DBCO thin films grown on SrTiO3 or LaAlO2 substrates, namely: the

  7. Ambient temperature and 17β-estradiol modify Fos immunoreactivity in the median preoptic nucleus, a putative regulator of skin vasomotion.

    PubMed

    Dacks, Penny A; Krajewski, Sally J; Rance, Naomi E

    2011-07-01

    Estrogen has pronounced effects on thermoregulation, but the anatomic sites of integration between the reproductive and thermoregulatory axes are unknown. In this study, we tested whether estradiol-17β (E(2)) treatment would alter the activity of thermoregulatory brain regions responding to mild changes in ambient temperature (T(AMBIENT)). Core and tail skin temperatures were recorded at the ambient temperatures of 20, 24, or 31 C in ovariectomized (OVX) rats with and without E(2). Neuronal activity was evaluated by counting the number of Fos-immunoreactive cells in the brains of rats killed 90 min after exposure to one of the three ambient temperatures. Of 14 brain areas examined, the median preoptic nucleus (MnPO) was the only site that exhibited increased Fos immunoreactivity at the high T(AMBIENT) of 31 C. At 24 C, OVX rats exhibited increased numbers of MnPO Fos-immunoreactive cells, compared with OVX + E(2) rats. Interestingly, tail skin vasomotion and MnPO Fos expression were affected in a similar manner by T(AMBIENT) and E(2) treatment. In the arcuate nucleus and anteroventral periventricular nucleus (AVPV), Fos immunoreactivity was highest at the low T(AMBIENT) of 20 C, with inhibitory (arcuate nucleus) and stimulatory (AVPV) effects of E(2). No other areas responded to both T(AMBIENT) and E(2) treatment. These results implicate the MnPO, the arcuate nucleus, and the AVPV as sites of integration between the reproductive and thermoregulatory axes. Combined with studies showing the importance of MnPO neurons in heat-defense pathways, the MnPO emerges as a likely site for E(2) modulation of thermoregulatory vasomotion.

  8. Ambient temperature effects on photo induced gonadal cycles and hormonal secretion patterns in Great Tits from three different breeding latitudes.

    PubMed

    Silverin, Bengt; Wingfield, John; Stokkan, Karl-Arne; Massa, Renato; Järvinen, Antero; Andersson, Nils-Ake; Lambrechts, Marcel; Sorace, Alberto; Blomqvist, Donald

    2008-06-01

    The present study determines how populations of Great Tits (Parus major) breeding in southern, mid and northern European latitudes have adjusted their reproductive endocrinology to differences in the ambient temperature during the gonadal cycle. A study based on long-term breeding data, using the Colwell predictability model, showed that the start of the breeding season has a high predictability ( approximately 0.8-0.9) at all latitudes, and that the environmental information factor (I(e)) progressively decreased from mid Italy (I(e)>4) to northern Finland (I(e)<1). The results indicate that integration of supplementary information, such as ambient temperature, with photoperiodic initial predictive information (day length), becomes progressively more important in maintaining the predictability of the breeding season with decreasing latitude. This hypothesis was verified by exposing photosensitive Great Tits from northern Norway, southern Sweden and northern Italy to sub-maximal photo-stimulatory day lengths (13L:11D) under two different ambient temperature regimes (+4 degrees C and +20 degrees C). Changes in testicular size, plasma levels of LH and testosterone were measured. The main results were: (1) Initial testicular growth rate, as well as LH secretion, was affected by temperature in the Italian, but not in birds from the two Scandinavian populations. (2) Maximum testicular size, maximum LH and testosterone levels were maintained for a progressively shorter period of time with increasing latitude, regardless of whether the birds were kept on a low or a high ambient temperature. (3) In birds from all latitudes, the development of photorefractoriness, as indicated by testicular regression and a decrease in plasma levels of LH and testosterone, started much earlier (with the exception for LH Great Tits from northern Scandinavia) when kept on +20 degrees C than when kept on +4 degrees C. The prolonging effects of a low temperature was more pronounced in

  9. Ambient temperature influences tolerance to plant secondary compounds in a mammalian herbivore

    PubMed Central

    Kurnath, P.; Merz, N. D.; Dearing, M. D.

    2016-01-01

    Growing evidence suggests that plant secondary compounds (PSCs) ingested by mammals become more toxic at elevated ambient temperatures, a phenomenon known as temperature-dependent toxicity. We investigated temperature-dependent toxicity in the desert woodrat (Neotoma lepida), a herbivorous rodent that naturally encounters PSCs in creosote bush (Larrea tridentata), which is a major component of its diet. First, we determined the maximum dose of creosote resin ingested by woodrats at warm (28–29°C) or cool (21–22°C) temperatures. Second, we controlled the daily dose of creosote resin ingested at warm, cool and room (25°C) temperatures, and measured persistence in feeding trials. At the warm temperature, woodrats ingested significantly less creosote resin; their maximum dose was two-thirds that of animals at the cool temperature. Moreover, woodrats at warm and room temperatures could not persist on the same dose of creosote resin as woodrats at the cool temperature. Our findings demonstrate that warmer temperatures reduce PSC intake and tolerance in herbivorous rodents, highlighting the potentially adverse consequences of temperature-dependent toxicity. These results will advance the field of herbivore ecology and may hone predictions of mammalian responses to climate change. PMID:26763703

  10. Generation of electricity in microbial fuel cells at sub-ambient temperatures

    NASA Astrophysics Data System (ADS)

    Catal, Tunc; Kavanagh, Paul; O'Flaherty, Vincent; Leech, Dónal

    2011-03-01

    Direct generation of electricity from a mixture of carbon sources was examined using single chamber mediator-less air cathode microbial fuel cells (MFCs) at sub-ambient temperatures. Electricity was directly generated from a carbon source mixture of D-glucose, D-galactose, D-xylose, D-glucuronic acid and sodium acetate at 30 °C and <20 °C (down to 4 °C). Anodic biofilms enriched at different temperatures using carbon source mixtures were examined using epi-fluorescent, scanning electron microscopy, and cyclic voltammetry for electrochemical evaluation. The maximum power density obtained at different temperatures ranged from 486 ± 68 mW m-2 to 602 ± 38 mW m-2 at current density range of 0.31 mA cm-2 to 0.41 mA cm-2 (14 °C and 30 °C, respectively). Coulombic efficiency increased with decreasing temperature, and ranged from 24 ± 3 to 38 ± 1% (20 °C and 4 °C, respectively). Chemical oxygen demand (COD) removal was over 68% for all carbon sources tested. Our results demonstrate adaptation, by gradual increase of cold-stress, to electricity production in MFCs at sub-ambient temperatures.

  11. Thermal responses and perceptions under distinct ambient temperature and wind conditions.

    PubMed

    Shimazaki, Yasuhiro; Yoshida, Atsumasa; Yamamoto, Takanori

    2015-01-01

    Wind conditions are widely recognized to influence the thermal states of humans. In this study, we investigated the relationship between wind conditions and thermal perception and energy balance in humans. The study participants were exposed for 20 min to 3 distinct ambient temperatures, wind speeds, and wind angles. During the exposure, the skin temperatures as a physiological reaction and mental reactions of the human body were measured and the energy balance was calculated based on the human thermal-load method. The results indicate that the human thermal load is an accurate indicator of human thermal states under all wind conditions. Furthermore, wind speed and direction by themselves do not account for the human thermal experience. Because of the thermoregulation that occurs to prevent heat loss and protect the core of the body, a low skin temperature was maintained and regional differences in skin temperature were detected under cool ambient conditions. Thus, the human thermal load, which represents physiological parameters such as skin-temperature change, adequately describes the mixed sensation of the human thermal experience.

  12. Modeling and open-loop control of IPMC actuators under changing ambient temperature

    NASA Astrophysics Data System (ADS)

    Dong, Roy; Tan, Xiaobo

    2012-06-01

    Because of the cost and complexity associated with sensory feedback, open-loop control of ionic polymer-metal composite (IPMC) actuators is of interest in many biomedical and robotic applications. However, the performance of an open-loop controller is sensitive to the change in IPMC dynamics, which is influenced heavily by ambient environmental conditions including the temperature. In this paper we propose a novel approach to the modeling and open-loop control of temperature-dependent IPMC actuation dynamics. An IPMC actuator is modeled empirically with a transfer function, the zeros and poles of which are functions of the temperature. With auxiliary temperature measurement, open-loop control is realized by inverting the model at the current ambient temperature. We use a stable but noncausal algorithm to deal with non-minimum-phase zeros in the system that would prevent directly inverting the dynamics. Experimental results are presented to show the effectiveness of the proposed approach in open-loop tracking control of IPMC actuators.

  13. The Effect of Ambient Temperature on the Cardiovascular Responses to Microgravity as Simulated by six Degrees Head Down Tilt (HDT)

    NASA Astrophysics Data System (ADS)

    Nangalia, Vishal; Ernsting, John

    Background: To determine the effect of ambient temperature on the thermoregulatory and cardiovascular responses to microgravity as simulated by six degrees head down tilt (HDT). Hypothesis: The thermoregulatory and cardiovascular responses to 6°HDT are unaffected by ambient temperatures between 12° and 32°C. Method: Each of five volunteer subjects (18-24 y.) underwent three separate 6 h exposures in a climatic chamber whilst lying supine with 6°HDT. The ambient temperatures for the first 5 h of the exposure were 12°, 22° and 32°C. At the beginning of the sixth hour, the ambient temperature was either increased or decreased by 10°C depending on the initial temperature. Heart rate, blood pressure, forearm bloodflow, core and skin temperatures, urine output and body weight were measured before, during and after each exposure. Results: Mean arterial pressure was increased in all exposures, though the increase varied with the ambient temperature. Pulse pressure after 5 h HDT increased in the 32°C exposure, remained unchanged at 22°C and decreased at 12°C. The threshold for thermoregulatory increases in forearm vascular conductance was lowered. Core temperature of the body increased in the exposures to 32°C and 22°C. The reduction in body weight (mean 1 kg.) was identical in all exposures whilst the urine output varied with ambient temperature. No significant changes occurred in any variable when the ambient temperature was changed by 10°C at the end of the fifth hour. Conclusions: The cardiovascular responses to 6 h exposure to 6° HDT, are affected by the ambient temperature.

  14. High temperature LSI

    NASA Technical Reports Server (NTRS)

    Dening, D. C.; Ragonese, L. J.; Lee, C. Y.

    1982-01-01

    Integrated injection logic (1,2) technology for reliable operation under a -55 C to +300 C, temperature range is discussed. Experimental measurements indicate that an 80 mv signal swing is available at 300 C with 100 micro A injection current per gate. In addition, modeling results predict how large gate fan-ins can decrease the maximum thermal operational limits. These operational limits and the longterm reliability factors associated with device metallization are evaluated via specialized test mask.

  15. Responses of wheat and rice to factorial combinations of ambient and elevated CO2 and temperature in FACE experiments.

    PubMed

    Cai, Chuang; Yin, Xinyou; He, Shuaiqi; Jiang, Wenyu; Si, Chuanfei; Struik, Paul C; Luo, Weihong; Li, Gang; Xie, Yingtian; Xiong, Yan; Pan, Genxing

    2016-02-01

    Elevated CO2 and temperature strongly affect crop production, but understanding of the crop response to combined CO2 and temperature increases under field conditions is still limited while data are scarce. We grew wheat (Triticum aestivum L.) and rice (Oryza sativa L.) under two levels of CO2 (ambient and enriched up to 500 μmol mol(-1) ) and two levels of canopy temperature (ambient and increased by 1.5-2.0 °C) in free-air CO2 enrichment (FACE) systems and carried out a detailed growth and yield component analysis during two growing seasons for both crops. An increase in CO2 resulted in higher grain yield, whereas an increase in temperature reduced grain yield, in both crops. An increase in CO2 was unable to compensate for the negative impact of an increase in temperature on biomass and yield of wheat and rice. Yields of wheat and rice were decreased by 10-12% and 17-35%, respectively, under the combination of elevated CO2 and temperature. The number of filled grains per unit area was the most important yield component accounting for the effects of elevated CO2 and temperature in wheat and rice. Our data showed complex treatment effects on the interplay between preheading duration, nitrogen uptake, tillering, leaf area index, and radiation-use efficiency, and thus on yield components and yield. Nitrogen uptake before heading was crucial in minimizing yield loss due to climate change in both crops. For rice, however, a breeding strategy to increase grain number per m(2) and % filled grains (or to reduce spikelet sterility) at high temperature is also required to prevent yield reduction under conditions of global change.

  16. Impacts of ambient temperature on the burden of bacillary dysentery in urban and rural Hefei, China.

    PubMed

    Cheng, J; Xie, M Y; Zhao, K F; Wu, J J; Xu, Z W; Song, J; Zhao, D S; Li, K S; Wang, X; Yang, H H; Wen, L Y; Su, H; Tong, S L

    2017-03-15

    Bacillary dysentery continues to be a major health issue in developing countries and ambient temperature is a possible environmental determinant. However, evidence about the risk of bacillary dysentery attributable to ambient temperature under climate change scenarios is scarce. We examined the attributable fraction (AF) of temperature-related bacillary dysentery in urban and rural Hefei, China during 2006-2012 and projected its shifting pattern under climate change scenarios using a distributed lag non-linear model. The risk of bacillary dysentery increased with the temperature rise above a threshold (18·4 °C), and the temperature effects appeared to be acute. The proportion of bacillary dysentery attributable to hot temperatures was 18·74% (95 empirical confidence interval (eCI): 8·36-27·44%). Apparent difference of AF was observed between urban and rural areas, with AF varying from 26·87% (95% eCI 16·21-36·68%) in urban area to -1·90% (95 eCI -25·03 to 16·05%) in rural area. Under the climate change scenarios alone (1-4 °C rise), the AF from extreme hot temperatures (>31·2 °C) would rise greatly accompanied by the relatively stable AF from moderate hot temperatures (18·4-31·2 °C). If climate change proceeds, urban area may be more likely to suffer from rapidly increasing burden of disease from extreme hot temperatures in the absence of effective mitigation and adaptation strategies.

  17. High temperature superconductors for magnetic suspension applications

    NASA Technical Reports Server (NTRS)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  18. Chamber validation of a passive air sampling device for measuring ambient VOCs at subzero temperatures

    SciTech Connect

    Gagner, R.V.; Hrudey, S.E.

    1997-12-31

    An evaluation was made of the performance of the 3M Organic Vapor Monitor No. 3500 through experiments conducted under permeation tube generated atmospheres in a controlled chamber environment. A range of typical ambient benzene and toluene concentrations were produced in the chamber to test the consistency of the sampling rate under different exposure levels. All tests were repeated at room temperature, and under subzero Celsius conditions to determine the effect of lowered temperatures on the performance of the badge. As expected, relatively low concentrations of benzene and toluene produced small incremental increases in analyte above the background levels inherent to the badge and analytical methods resulting in a loss of method precision. The badge sampling rate was not significantly affected by decreases in temperature to minus fifteen degrees Celsius. This finding was not consistent with the theoretically-based temperature correction factors identified in the product literature.

  19. The effects of high ambient radon on thermoluminescence dosimetry readings.

    PubMed

    Harvey, John A; Kearfott, Kimberlee J

    2011-11-01

    The effect of a high level of ambient (222)Rn gas on thermoluminescence dosemeters (TLDs) is examined. Groups of LiF:Mg,Ti and CaF(2):Dy TLDs were exposed to (222)Rn under controlled environmental conditions over ∼7 d using a luminous (226)Ra aircraft dial. LiF:Mg,Ti TLDs were tested bare, and both types were tested mounted in cards used for environmental dosimetry and mounted in cards enclosed in plastic badges. A passive continuous radon monitor was used to measure the (222)Rn level in the small chamber during the experiments. The data were analysed to determine the relationship between the integrated (222)Rn level and the TLD response. Although both LiF:Mg,Ti and CaF(2):Dy TLDs showed a strong response to (222)Rn, the badges prevented measurable radon detection by the TLDs within. The TLDs were not used to directly measure the radon concentration; rather, a correction for its influence was desired.

  20. High-temperature constitutive modeling

    NASA Technical Reports Server (NTRS)

    Robinson, D. N.; Ellis, J. R.

    1984-01-01

    Thermomechanical service conditions for high-temperature levels, thermal transients, and mechanical loads severe enough to cause measurable inelastic deformation are studied. Structural analysis in support of the design of high-temperature components depends strongly on accurate mathematical representations of the nonlinear, hereditary, inelastic behavior of structural alloys at high temperature, particularly in the relatively small strain range. Progress is discussed in the following areas: multiaxial experimentation to provide a basis for high-temperature multiaxial constitutive relationships; nonisothermal testing and theoretical development toward a complete thermomechanically path dependent formulation of viscoplasticity; and development of viscoplastic constitutive model accounting for initial anisotropy.

  1. Effects of Social Interaction and Warm Ambient Temperature on Brain Hyperthermia Induced by the Designer Drugs Methylone and MDPV

    PubMed Central

    Kiyatkin, Eugene A; Kim, Albert H; Wakabayashi, Ken T; Baumann, Michael H; Shaham, Yavin

    2015-01-01

    3,4-Methylenedioxymethcathinone (methylone) and 3,4-methylenedioxypyrovalerone (MDPV) are new drugs of abuse that have gained worldwide popularity. These drugs are structurally similar to 3,4-methylenedioxymethamphetamine (MDMA) and share many of its physiological and behavioral effects in humans, including the development of hyperthermia during acute intoxication. Here, we examined the effects of methylone (1–9 mg/kg, s.c.) or MDPV (0.1–1.0 mg/kg, s.c.) on brain temperature homeostasis in rats maintained in a standard laboratory environment (single-housed in a quiet rest at 22 °C) and under conditions that model human drug use (social interaction and 29 °C ambient temperature). By simultaneously monitoring temperatures in the nucleus accumbens, temporal muscle, and facial skin, we assessed the effects of methylone and MDPV on intra-brain heat production and cutaneous vascular tone, two critical factors that control brain temperature responses. Both methylone and MDPV dose-dependently increased brain temperature, but even at high doses that induced robust locomotor activation, hyperthermia was modest in magnitude (up to ∼2 °C). Both drugs also induced dose-dependent peripheral vasoconstriction, which appears to be a primary mechanism determining the brain hyperthermic responses. In contrast to the powerful potentiation of MDMA-induced hyperthermia by social interaction and warm ambient temperature, such potentiation was absent for methylone and minimal for MDPV. Taken together, despite structural similarities to MDMA, exposure to methylone or MDPV under conditions commonly associated with human drug use does not lead to profound elevations in brain temperature and sustained vasoconstriction, two critical factors associated with MDMA toxicity. PMID:25074640

  2. Effects of social interaction and warm ambient temperature on brain hyperthermia induced by the designer drugs methylone and MDPV.

    PubMed

    Kiyatkin, Eugene A; Kim, Albert H; Wakabayashi, Ken T; Baumann, Michael H; Shaham, Yavin

    2015-01-01

    3,4-Methylenedioxymethcathinone (methylone) and 3,4-methylenedioxypyrovalerone (MDPV) are new drugs of abuse that have gained worldwide popularity. These drugs are structurally similar to 3,4-methylenedioxymethamphetamine (MDMA) and share many of its physiological and behavioral effects in humans, including the development of hyperthermia during acute intoxication. Here, we examined the effects of methylone (1-9 mg/kg, s.c.) or MDPV (0.1-1.0 mg/kg, s.c.) on brain temperature homeostasis in rats maintained in a standard laboratory environment (single-housed in a quiet rest at 22 °C) and under conditions that model human drug use (social interaction and 29 °C ambient temperature). By simultaneously monitoring temperatures in the nucleus accumbens, temporal muscle, and facial skin, we assessed the effects of methylone and MDPV on intra-brain heat production and cutaneous vascular tone, two critical factors that control brain temperature responses. Both methylone and MDPV dose-dependently increased brain temperature, but even at high doses that induced robust locomotor activation, hyperthermia was modest in magnitude (up to ∼2 °C). Both drugs also induced dose-dependent peripheral vasoconstriction, which appears to be a primary mechanism determining the brain hyperthermic responses. In contrast to the powerful potentiation of MDMA-induced hyperthermia by social interaction and warm ambient temperature, such potentiation was absent for methylone and minimal for MDPV. Taken together, despite structural similarities to MDMA, exposure to methylone or MDPV under conditions commonly associated with human drug use does not lead to profound elevations in brain temperature and sustained vasoconstriction, two critical factors associated with MDMA toxicity.

  3. High-temperature-measuring device

    DOEpatents

    Not Available

    1981-01-27

    A temperature measuring device for very high design temperatures (to 2000/sup 0/C) is described. The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensonally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  4. Genetic variation of body temperature of Coturnix coturnix in two ambient temperatures.

    PubMed

    Becker, W A; Harrison, P

    1975-05-01

    Coturnix quail were placed in an environmental chamber maintained at 21 degree C. and rectal temperatures taken. The birds were subjected to an abrupt change to 36 degree C. and the temperatures taken hourly for eight hours and at 25, 38 and 72 hours. Females had higher temperatures than males. When birds were moved to 36 degrees C. their temperatures rose rapidly and then dropped to a level higher than when birds were in the 21 degrees C. chamber. The genetic and total variation estimated from the analysis of variance method decreased under this sudden thermal stress condition. Birds kept in 36 degrees C. for three weeks were shifted to 21 degrees C. Their body temperature dropped sharply and then increased to a level lower than that obtained in the 36 degrees C. environment. The genetic variation was essentially zero when shifted to a lower temperature while the total variation increased.

  5. High temperature interface superconductivity

    NASA Astrophysics Data System (ADS)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  6. High temperature interface superconductivity

    DOE PAGES

    Gozar, A.; Bozovic, I.

    2016-01-20

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. Here, wemore » conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.« less

  7. High temperature interface superconductivity

    SciTech Connect

    Gozar, A.; Bozovic, I.

    2016-01-20

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. Here, we conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  8. Correction: Ambient temperature deposition of gallium nitride/gallium oxynitride from a deep eutectic electrolyte, under potential control.

    PubMed

    Sarkar, Sujoy; Sampath, S

    2016-05-28

    Correction for 'Ambient temperature deposition of gallium nitride/gallium oxynitride from a deep eutectic electrolyte, under potential control' by Sujoy Sarkar et al., Chem. Commun., 2016, 52, 6407-6410.

  9. High-temperature conventional superconductivity

    NASA Astrophysics Data System (ADS)

    Eremets, M. I.; Drozdov, A. P.

    2017-02-01

    Conventional superconductors are described well by the Bardeen – Cooper – Schrieffer (BCS) theory (1957) and its related theories, all of which importantly put no explicit limit on transition temperature Tc. While this allows, in principle, room-temperature superconductivity, no such phenomenon has been observed. Since the discovery of superconductivity in 1911, the measured critical temperature of BCS superconductors has not until recently exceeded 39 K. In 2014, hydrogen sulfide under high pressure was experimentally found to exhibit superconductivity at Tc = 200 K, a record high value which greatly exceeds that of the previous class of high-temperature superconductors, the cuprates. The superconductivity mechanism in cuprates has not yet been explained. Over a period of 25 years, the critical temperature of cuprates has not been increased above 164 K. The paper reviews research on record-high Tc superconductivity in hydrogen sulphide and other hydrides. Prospects for increasing Tc to room temperature are also discussed.

  10. High-temperature conventional superconductivity

    NASA Astrophysics Data System (ADS)

    Eremets, M. I.; Drozdov, A. P.

    2016-11-01

    Conventional superconductors are described well by the Bardeen - Cooper - Schrieffer (BCS) theory (1957) and its related theories, all of which importantly put no explicit limit on transition temperature T_c. While this allows, in principle, room-temperature superconductivity, no such phenomenon has been observed. Since the discovery of superconductivity in 1911, the measured critical temperature of BCS superconductors has not until recently exceeded 39 K. In 2014, hydrogen sulfide under high pressure was experimentally found to exhibit superconductivity at T_c=200 K, a record high value which greatly exceeds that of the previous class of high-temperature superconductors, the cuprates. The superconductivity mechanism in cuprates has not yet been explained. Over a period of 25 years, the critical temperature of cuprates has not been increased above 164 K. The paper reviews research on record-high T_c superconductivity in hydrogen sulphide and other hydrides. Prospects for increasing T_c to room temperature are also discussed.

  11. High-temperature ceramic receivers

    SciTech Connect

    Jarvinen, P. O.

    1980-01-01

    An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

  12. Systematics of an ambient-temperature, rapidly-rotating half-wave plate

    NASA Astrophysics Data System (ADS)

    Essinger-Hileman, T.; Kusaka, A.; Appel, J. W.; Gallardo, P.; Irwin, K. D.; Jarosik, N.; Nolta, M. R.; Page, L. A.; Parker, L. P.; Raghunathan, S.; Sievers, J. L.; Simon, S. M.; Staggs, S. T.; Visnjic, K.

    2016-07-01

    In these proceedings, we summarize our in-field evaluation of temperature-to-polarization leakage associated with the use of a continuously-rotating, ambient-temperature half-wave plate (HWP) on the Atacama B-Mode Search (ABS) experiment. Using two seasons of data, we demonstrate scalar leakage of ˜ 0.01%. This is consistent with model expectations and an order of magnitude better than any previously-reported leakage. We constrain higher-order dipole and quadrupole leakage terms to be < 0.06% (95% confidence). Without any mitigation from scan cross-linking or boresight rotation, this corresponds to an upper limit on systematic errors in the tensor-to-scalar ratio r ;S 0.01. The HWP significantly reduces temperature-to-polarization leakage systematic errors for ABS and shows the promise of fast polarization modulation with HWPs for future experiments. Full details can be found in Ref. 1.

  13. High temperature skin friction measurement

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

    1989-01-01

    Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

  14. Ambient-Temperature Passive Magnetic Bearings for Flywheel Energy Storage Systems

    SciTech Connect

    Bender, D.; Post, R.

    2000-05-26

    Based on prior work at the Lawrence Livermore National Laboratory ambient-temperature passive magnetic bearings are being adapted for use in high-power flywheel energy storage systems developed at the Trinity Flywheel Power company. En route to this goal specialized test stands have been built and computer codes have been written to aid in the development of the component parts of these bearing systems. The Livermore passive magnetic bearing system involves three types of elements, as follows: (1) Axially symmetric levitation elements, energized by permanent magnets., (2) electrodynamic ''stabilizers'' employing axially symmetric arrays of permanent magnet bars (''Halbach arrays'') on the rotating system, interacting with specially wound electrically shorted stator circuits, and, (3) eddy-current-type vibration dampers, employing axially symmetric rotating pole assemblies interacting with stationary metallic discs. The theory of the Livermore passive magnetic bearing concept describes specific quantitative stability criteria. The satisfaction of these criteria will insure that, when rotating above a low critical speed, a bearing system made up of the three elements described above will be dynamically stable. That is, it will not only be stable for small displacements from equilibrium (''Earnshaw-stable''), but will also be stable against whirl-type instabilities of the types that can arise from displacement-dependent drag forces, or from mechanical-hysteritic losses that may occur in the rotor. Our design problem thus becomes one of calculating and/or measuring the relevant stiffnesses and drag coefficients of the various elements and comparing our results with the theory so as to assure that the cited stability criteria are satisfied.

  15. Effect of Ambient and Oxygen Temperature on Flow Field Characteristics of Coherent Jet

    NASA Astrophysics Data System (ADS)

    Liu, Fuhai; Zhu, Rong; Dong, Kai; Hu, Shaoyan

    2016-02-01

    The coherent jets are now used widely in electric arc furnace steelmaking process to increase the stirring ability, reaction rates, and energy efficiency. However, there has been limited research on the basic physics of the coherent jets. In the present study, the characteristics of flow field of supersonic coherent jet in hot and cold condition were studied. The total temperature and axial velocity were measured by combustion experiment. Flow field characteristics of supersonic coherent jet were simulated by Fluent software. The detailed chemical kinetic mechanism is presently used for the modeling of reactions. It consists of 53 species, plus Ar and N2, for a total of 325 reversible reactions. The present study showed that the shrouding flame decreases the entrainment of the ambient gas to the central supersonic jet, which results in a low expansion rate for the coherent supersonic jet. The higher ambient temperature can prolong the potential core of coherent jet and conventional jet. However, the potential core of coherent jet reduces with oxygen temperature increasing, which is opposite to conventional jet.

  16. Cold Ambient Temperature Promotes Nosema spp. Intensity in Honey Bees (Apis mellifera).

    PubMed

    Retschnig, Gina; Williams, Geoffrey R; Schneeberger, Annette; Neumann, Peter

    2017-02-09

    Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera) colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous endoparasite of Western HBs, the impact of weather conditions on the distribution of this microsporidian in the field is poorly understood. Here, we conducted a survey for Nosema spp. using 18 Swiss apiaries (four colonies per apiary) over a period of up to 18 months. Samples consisting of 60 workers were collected monthly from each colony to estimate Nosema spp. intensity, i.e., the number of spores in positive samples using microscopy. Ambient apiary temperature was measured daily to estimate the proportion of days enabling HB flight (>10 °C at midday). The results show that Nosema spp. intensities were negatively correlated with the proportion of days enabling HB flight, thereby suggesting a significant and unexpected positive impact of cold ambient temperature on intensities, probably via regulation of defecation opportunities for infected hosts.

  17. Cold Ambient Temperature Promotes Nosema spp. Intensity in Honey Bees (Apis mellifera)

    PubMed Central

    Retschnig, Gina; Williams, Geoffrey R.; Schneeberger, Annette; Neumann, Peter

    2017-01-01

    Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera) colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous endoparasite of Western HBs, the impact of weather conditions on the distribution of this microsporidian in the field is poorly understood. Here, we conducted a survey for Nosema spp. using 18 Swiss apiaries (four colonies per apiary) over a period of up to 18 months. Samples consisting of 60 workers were collected monthly from each colony to estimate Nosema spp. intensity, i.e., the number of spores in positive samples using microscopy. Ambient apiary temperature was measured daily to estimate the proportion of days enabling HB flight (>10 °C at midday). The results show that Nosema spp. intensities were negatively correlated with the proportion of days enabling HB flight, thereby suggesting a significant and unexpected positive impact of cold ambient temperature on intensities, probably via regulation of defecation opportunities for infected hosts. PMID:28208761

  18. Effects of ambient and preceding temperatures and metabolic genes on flight metabolism in the Glanville fritillary butterfly.

    PubMed

    Wong, Swee Chong; Oksanen, Alma; Mattila, Anniina L K; Lehtonen, Rainer; Niitepõld, Kristjan; Hanski, Ilkka

    2016-02-01

    Flight is essential for foraging, mate searching and dispersal in many insects, but flight metabolism in ectotherms is strongly constrained by temperature. Thermal conditions vary greatly in natural populations and may hence restrict fitness-related activities. Working on the Glanville fritillary butterfly (Melitaea cinxia), we studied the effects of temperature experienced during the first 2 days of adult life on flight metabolism, genetic associations between flight metabolic rate and variation in candidate metabolic genes, and genotype-temperature interactions. The maximal flight performance was reduced by 17% by 2 days of low ambient temperature (15 °C) prior to the flight trial, mimicking conditions that butterflies commonly encounter in nature. A SNP in phosphoglucose isomerase (Pgi) had a significant association on flight metabolic rate in males and a SNP in triosephosphate isomerase (Tpi) was significantly associated with flight metabolic rate in females. In the Pgi SNP, AC heterozygotes had higher flight metabolic rate than AA homozygotes following low preceding temperature, but the trend was reversed following high preceding temperature, consistent with previous results on genotype-temperature interaction for this SNP. We suggest that these results on 2-day old butterflies reflect thermal effect on the maturation of flight muscles. These results highlight the consequences of variation in thermal conditions on the time scale of days, and they contribute to a better understanding of the complex dynamics of flight metabolism and flight-related activities under conditions that are relevant for natural populations living under variable thermal conditions.

  19. Ambient Noise Tomography of Canada: Crustal Structures, Lithosphere Temperatures and Topography

    NASA Astrophysics Data System (ADS)

    Currie, C. A.; Kao, H.; Behr, Y.; Hyndman, R. D.; Townend, J.

    2012-12-01

    The continental lithosphere of Canada contains a record of tectonic events that have shaped this region over the last 4 Ga, from the ancient orogens that formed the cratonic core to ongoing deformation of the more juvenile accreted terranes of the Canadian Cordillera. This study presents the first continental-scale study of the shear wave velocity structure of Canada using ambient noise tomography, which allows better resolution than previous tomography models based on earthquake waveforms. The analysis includes data recorded from 2003 to 2009 at 788 seismic stations covering Canada and adjacent regions. Vertical-component recordings are used to map Rayleigh wave velocities at different periods and thereby construct a pseudo-3D shear wave velocity (Vs) model extending to ~100 km depth. The Vs model exhibits pronounced spatial variations. Within the Canadian Cordillera, a velocity discontinuity is observed at ~10 km depth that may mark a mid-crustal detachment separating largely felsic upper crustal rocks from more mafic rocks. In the stable craton region, velocity variations appear to correspond with terrane boundaries mapped in surface geology. Crustal thickness varies between 30 and 50 km, with the thinnest crust below the Canadian Cordillera and thicker crust underlying the southwest part of the Western Canada Sedimentary Basin, the northern United States between 90W and 115W, and Lake Erie. In many areas, the Moho is a well-defined velocity discontinuity of a few km, but in some places (e.g., the western edge of the Western Canada Sedimentary Basin), the velocities exhibit a vertical gradation over ~10 km, suggesting that there may be a zone of mixing between crustal and mantle rocks or areas where the lowermost crust is partially eclogitized. In the mantle, the largest velocity contrast is between the low velocity Canadian Cordillera and the high velocity craton. Within the craton, there are well-resolved regional variations that appear to correspond with

  20. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    PubMed Central

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-01-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy. PMID:27883063

  1. Photocatalyst-Free and Blue Light-Induced RAFT Polymerization of Vinyl Acetate at Ambient Temperature.

    PubMed

    Ding, Chunlai; Fan, Caiwei; Jiang, Ganquan; Pan, Xiangqiang; Zhang, Zhengbiao; Zhu, Jian; Zhu, Xiulin

    2015-12-01

    Vinyl acetate is polymerized in the living way under the irradiation of blue light-emitting diodes (LEDs) or sunlight without photocatalyst at ambient temperature. 2-(Ethoxycarbonothioyl)sulfanyl propanoate is exclusively added and acts as initiator and chain transfer agent simultaneously in the current system. Poly(vinyl acetate) with well-regulated molecular weight and narrow molecular weight distribution (Đ < 1.30) is synthesized. Near quantitative end group fidelity of polymer is demonstrated by nuclear magnetic resonance (NMR) and matrix-assisteed laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

  2. Variation of output with atmospheric pressure and ambient temperature for Therac-20 linear accelerator.

    PubMed

    Sharma, S C; Wilson, D L; Jose, B

    1983-01-01

    The Therac-20 (a linear accelerator manufactured by the Atomic Energy of Canada, Ltd.) employs an unsealed monitor chamber to control the dose output. Daily fluctuations in machine output for both x rays and electron beams were observed to vary with ambient temperature and atmospheric pressure. These variations were not related to any other machine parameters. Variations as large as 3.5% were seen by monitoring 18-MV x-ray output over several months. We recommend that the manufacturers take steps to eliminate the atmospheric dependence of dose rate.

  3. Interdiffusion of Al-Ni system enhanced by ultrasonic vibration at ambient temperature.

    PubMed

    Li, Mingyu; Ji, Hongjun; Wang, Chunqing; Bang, Han Sur; Bang, Hee Seon

    2006-12-01

    At ambient temperature, Al-1%Si wire of 25 microm diameter was bonded successfully onto the Au/Ni/Cu pad by ultrasonic wedge bonding technology. Physical process of the bond formation and the interface joining essence were investigated. It is found that the wire was softened by ultrasonic vibration, at the same time, pressure was loaded on the wire and plastic flow was generated in the bonding wire, which promoted the diffusion for Ni into Al. Ultrasonic vibration enhanced the interdiffusion that resulted from the inner defects such as dislocations, vacancies, voids and so on, which ascribed to short circuit diffusion.

  4. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    NASA Astrophysics Data System (ADS)

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-11-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy.

  5. A positive association between cryptosporidiosis notifications and ambient temperature, Victoria, Australia, 2001-2009.

    PubMed

    Kent, Lillian; McPherson, Michelle; Higgins, Nasra

    2015-12-01

    Increased temperatures provide optimal conditions for pathogen survival, virulence and replication as well as increased opportunities for human-pathogen interaction. This paper examined the relationship between notifications of cryptosporidiosis and temperature in metropolitan and rural areas of Victoria, Australia between 2001 and 2009. A negative binomial regression model was used to analyse monthly average maximum and minimum temperatures, rainfall and the monthly count of cryptosporidiosis notifications. In the metropolitan area, a 1 °C increase in monthly average minimum temperature of the current month was associated with a 22% increase in cryptosporidiosis notifications (incident rate ratio (IRR) 1.22; 95% confidence interval (CI) 1.13-1.31). In the rural area, a 1 °C increase in monthly average minimum temperature, lagged by 3 months, was associated with a 9% decrease in cryptosporidiosis notifications (IRR 0.91; 95% CI 0.86-0.97). Rainfall was not associated with notifications in either area. These relationships should be considered when planning public health response to ecological risks as well as when developing policies involving climate change. Rising ambient temperature may be an early warning signal for intensifying prevention efforts, including appropriate education for pool users about cryptosporidiosis infection and management, which might become more important as temperatures are projected to increase as a result of climate change.

  6. Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint

    SciTech Connect

    Bharathan, D.; Nix, G.

    2001-08-06

    Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for use in power cycles. Such cycles are more readily amenable to use of absorption ''heat pumps.'' For a system that uses ammonia and water as the mixed-working fluid, this paper evaluates using an absorption heat pump to reduce condenser backpressure. At high ambient temperatures, part of the turbine exhaust vapor is absorbed into a circulating mixed stream in an absorber in series with the main condenser. This steam is pumped up to a higher pressure and heated to strip the excess vapor, which is recondensed using an additional air-cooled condenser. The operating conditions are chosen to reconstitute this condensate back to the same concentration as drawn from the original system. We analyzed two power plants of nominal 1-megawatt capacity. The design resource temperatures were 250 F and 300 F. Ambient temperature was allowed to rise from a design value of 50 F to 100 F. The analyses indicate that using an absorption heat pump is feasible. For the 300 F resource, an increased brine flow of 30% resulted in a net power increase of 21%. For the 250 F resource, the increase was smaller. However, these results are highly plant- and equipment-specific because evaluations must be carried out at off-design conditions for the condenser. Such studies should be carried out for specific power plants that suffer most from increased ambient temperatures.

  7. High Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

  8. The Influence of Ambient Temperature on Green Roof R-values

    NASA Astrophysics Data System (ADS)

    Cox, Bryce Kevin

    Green roofs can be an effective and appealing way to increase the energy efficiency of buildings by providing active insulation. As plants in the green roof transpire, there is a reduction in heat flux that is conducted through the green roof. The R-value, or thermal resistance, of a green roof is an effective measurement of thermal performance because it can be easily included in building energy calculations applicable to many different buildings and situations. The purpose of this study was to determine if an increase in ambient temperature would cause an increase in the R-value of green roofs. Test trays containing green roof materials were tested in a low speed wind tunnel equipped to determine the R-value of the trays. Three different plant species were tested in this study, ryegrass (Lolium perenne), sedum (Sedum hispanicum), and vinca (Vinca minor ). For each test in this study the relative humidity was maintained at 45% and the soil was saturated with water. The trays were tested at four different ambient temperatures, ranging from room temperature to 120ºF. The resulting R-values for sedum ranged from 1.37 to 3.28 ft2hºF/BTU, for ryegrass the R-values ranged from 2.15 to 3.62 ft2hºF/BTU, and for vinca the R-values ranged from 3.15 to 5.19 ft2hºF/BTU. The average R-value for all the tests in this study was 3.20 ft2hºF/BTU. The results showed an increase in R-value with increasing temperature. Applying an ANOVA analysis to the data, the relationship between temperature and R-value for all three plant species was found to be statistically significant.

  9. Revealing the association between cerebrovascular accidents and ambient temperature: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Zorrilla-Vaca, Andrés; Healy, Ryan Jacob; Silva-Medina, Melissa M.

    2016-10-01

    The association between cerebrovascular accidents (CVA) and weather has been described across several studies showing multiple conflicting results. In this paper, we aim to conduct a meta-analysis to further clarify this association, as well as to find the potential sources of heterogeneity. PubMed, EMBASE, and Google Scholar were searched from inception through 2015, for articles analyzing the correlation between the incidence of CVA and temperature. A pooled effect size (ES) was estimated using random effects model and expressed as absolute values. Subgroup analyses by type of CVA were also performed. Heterogeneity and influence of covariates—including geographic latitude of the study site, male percentage, average temperature, and time interval—were assessed by meta-regression analysis. Twenty-six articles underwent full data extraction and scoring. A total of 19,736 subjects with CVA from 12 different countries were included and grouped as ischemic strokes (IS; n = 14,199), intracerebral hemorrhages (ICH; n = 3798), and subarachnoid hemorrhages (SAH; n = 1739). Lower ambient temperature was significantly associated with increase in incidence of overall CVA when using unadjusted (pooled ES = 0.23, P < 0.001) and adjusted data (pooled ES = 0.03, P = 0.003). Subgroup analyses showed that lower temperature has higher impact on the incidence of ICH (pooled ES = 0.34, P < 0.001), than that of IS (pooled ES = 0.22, P < 0.001) and SAH (pooled ES = 0.11, P = 0.012). In meta-regression analysis, the geographic latitude of the study site was the most influencing factor on this association (Z-score = 8.68). Synthesis of the existing data provides evidence supporting that a lower ambient temperature increases the incidence of CVA. Further population-based studies conducted at negative latitudes are needed to clarify the influence of this factor.

  10. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

    SciTech Connect

    Narayan, Jagdish Bhaumik, Anagh

    2016-02-01

    We report a direct conversion of hexagonal boron nitride (h-BN) into pure cubic boron nitride (c-BN) by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN). The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

  11. Advanced High Temperature Structural Seals

    NASA Technical Reports Server (NTRS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-01-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  12. Ambient temperature affects glabrous skin vasculature and sweating responses to mental task in humans.

    PubMed

    Hayashi, Naoyuki; Someya, Nami; Hirooka, Yoshitaka; Koga, Shunsaku

    2008-09-01

    We compared responses in heart rate (HR), mean blood pressure (MAP), sweating rate (SR), sweating expulsion (SwE), and skin vascular conductance (VC) to mental task among different ambient temperature (Ta) conditions, i.e., 12, 16, 20, and 24 degrees C. Seven subjects (27+/-5 yrs, 64+/-14 kg) underwent a 2-min color word conflict test (CWT) after 2 mins of baseline data acquisition following a 20-min resting period. All subjects wore long sleeve shirts and long pants. The skin blood flow was measured with a laser Doppler probe on the left index finger pulp to calculate skin VC, and the SR and sweating expulsion (SwE) were measured with a ventilated capsule on the left thenar. CWT significantly increased the HR and MAP, while there was no significant effect of Ta on the magnitudes of these responses. CWT significantly decreased the skin VC when the Ta was 24 degrees C, whereas it significantly increased the skin VC when the Ta was 12 or 16 degrees C. CWT significantly increased SR and SwE in all Ta conditions, and the SwE was greater in warmer conditions. These findings suggest that different ambient temperatures induce different responses in finger skin vasculature to mental task, implying the independent response of cutaneous vasomotor tone and sweat glands in glabrous skin to mental task.

  13. CO2 sequestration by mineral carbonation of steel slags under ambient temperature: parameters influence, and optimization.

    PubMed

    Ghacham, Alia Ben; Pasquier, Louis-César; Cecchi, Emmanuelle; Blais, Jean-François; Mercier, Guy

    2016-09-01

    This work focuses on the influence of different parameters on the efficiency of steel slag carbonation in slurry phase under ambient temperature. In the first part, a response surface methodology was used to identify the effect and the interactions of the gas pressure, liquid/solid (L/S) ratio, gas/liquid ratio (G/L), and reaction time on the CO2 removed/sample and to optimize the parameters. In the second part, the parameters' effect on the dissolution of CO2 and its conversion into carbonates were studied more in detail. The results show that the pressure and the G/L ratio have a positive effect on both the dissolution and the conversion of CO2. These results have been correlated with the higher CO2 mass introduced in the reactor. On the other hand, an important effect of the L/S ratio on the overall CO2 removal and more specifically on the carbonate precipitation has been identified. The best results were obtained L/S ratios of 4:1 and 10:1 with respectively 0.046 and 0.052 gCO2 carbonated/g sample. These yields were achieved after 10 min reaction, at ambient temperature, and 10.68 bar of total gas pressure following direct gas treatment.

  14. Do circadian genes and ambient temperature affect substrate-borne signalling during Drosophila courtship?

    PubMed Central

    Medina, Izarne; Casal, José; Fabre, Caroline C. G.

    2015-01-01

    ABSTRACT Courtship vibratory signals can be air-borne or substrate-borne. They convey distinct and species-specific information from one individual to its prospective partner. Here, we study the substrate-borne vibratory signals generated by the abdominal quivers of the Drosophila male during courtship; these vibrations travel through the ground towards courted females and coincide with female immobility. It is not known which physical parameters of the vibrations encode the information that is received by the females and induces them to pause. We examined the intervals between each vibratory pulse, a feature that was reported to carry information for animal communication. We were unable to find evidence of periodic variations in the lengths of these intervals, as has been reported for fly acoustical signals. Because it was suggested that the genes involved in the circadian clock may also regulate shorter rhythms, we search for effects of period on the interval lengths. Males that are mutant for the period gene produced vibrations with significantly altered interpulse intervals; also, treating wild type males with constant light results in similar alterations to the interpulse intervals. Our results suggest that both the clock and light/dark cycles have input into the interpulse intervals of these vibrations. We wondered if we could alter the interpulse intervals by other means, and found that ambient temperature also had a strong effect. However, behavioural analysis suggests that only extreme ambient temperatures can affect the strong correlation between female immobility and substrate-borne vibrations. PMID:26519517

  15. Performance and physiological variables in broiler chicken lines differing in susceptibility to the ascites syndrome: 1. Changes in blood gases as a function of ambient temperature.

    PubMed

    Buys, N; Scheele, C W; Kwakernaak, C; van der Klis, J D; Decuypere, E

    1999-03-01

    1. Male broilers of 5 genetic stocks (A, B, C, D, E) selected in different ways for fast growth and low food conversion ratio (FCR) and differing in ascites sensitivity were subjected to 2 different ambient temperature step down regimens: high temperature (HT: 33 to 20 degrees C over 33 d) and low temperature (LT: 30 to 15 degrees C over 17 d). 2. Ascites incidence was recorded daily. Food intake and body weight gain were measured weekly and FCR was calculated. Heat production (Hp) was calculated using the comparative slaughter method. At 28 d venous samples were taken for blood gas analysis and haematocrit and relative heart, lung and liver weights were recorded. 3. Populations A and C showed the highest growth rates combined with a low FCR and a higher ascites incidence. A low FCR in these stocks was attributable to low values for Hp. These stocks also had low PO2 and high pCO2 in venous blood at low ambient temperature compared with other stocks. Stock B, which exhibited the slowest growth rate and the highest FCR, was not susceptible to ascites and showed higher Hp and PO2 and pCO2 at low ambient temperature. Populations D and E were intermediate for almost all variables. Heart and lung weights were both increased at LT, while liver weight did not differ between temperature regimes. 4. Our results show that a high haematocrit is not necessarily linked with an increased susceptibility to ascites.

  16. The effect of ambient temperature upon the secretion of thyroxine in the young pig.

    PubMed Central

    Evans, S E; Ingram, D L

    1977-01-01

    1. Fluctuations in the rate of secretion and metabolism of thyroxine in the pig were observed whilst the ambient temperature was reduced from 32 to 8 degrees C. The quantity of food supplied was either maintained constant or doubled when the animals were exposed to the lower temperature. 2. It was found that the rate of disappearance of [125I]thyroxine did not change when the animal was exposed to the cold, unless the animal's food intake was altered. 3. The secretion of thyroxine increased temporarily after exposure to the cold. This was shown by a rise in the concentration of thyroxine in the plasma and a simultaneously increased loss of 131I from the thyroid gland. The increase in secretion of thyroxine was not maintained throughout the exposure to cold when the food intake of the animal was kept constant. PMID:839465

  17. The Use of Chlorhexidine/n-Propyl Gallate (CPG) as an Ambient-Temperature Urine Preservative

    NASA Technical Reports Server (NTRS)

    Nillen, Jeannie L.; Smith, Scott M.

    2003-01-01

    A safe, effective ambient temperature urine preservative, chlorhexidine/n-propyl gallate (CPG), has been formulated for use during spacefli ght that reduces the effects of oxidation and bacterial contamination on sample integrity while maintaining urine pH. The ability of this preservative to maintain stability of nine key analytes was evaluated for a period of one year. CPG effectively maintained stability of a mmonia, total nitrogen, 3-methylhistidine, chloride, sodium, potassiu m, and urea; however, creatinine and osmolality were not preserved by CPG. These data indicate that CPG offers prolonged room-temperature storage for multiple urine analytes, reducing the requirements for f rozen urine storage on future spaceflights. Iii medical applications on Earth, this technology can allow urine samples to be collected in remote settings and eliminate the need to ship frozen samples.

  18. Humidity-resistant ambient-temperature solid-electrolyte amperometric sensing apparatus

    DOEpatents

    Zaromb, S.

    1994-06-21

    Apparatus and methods for detecting selected chemical compounds in air or other gas streams at room or ambient temperature includes a liquid-free humidity-resistant amperometric sensor comprising a sensing electrode and a counter and reference electrode separated by a solid electrolyte. The sensing electrode preferably contains a noble metal, such as Pt black. The electrolyte is water-free, non-hygroscopic, and substantially water-insoluble, and has a room temperature ionic conductivity [>=]10[sup [minus]4] (ohm-cm)[sup [minus]1], and preferably [>=]0.01 (ohm-cm)[sup [minus]1]. The conductivity may be due predominantly to Ag[sup +] ions, as in Ag[sub 2]WO[sub 4], or to F[sup [minus

  19. Ceramic Adhesive for High Temperatures

    NASA Technical Reports Server (NTRS)

    Stevens, Everett G.

    1987-01-01

    Fused-silica/magnesium-phosphate adhesive resists high temperatures and vibrations. New adhesive unaffected by extreme temperatures and vibrations. Assuring direct bonding of gap filters to tile sidewalls, adhesive obviates expensive and time-consuming task of removal, treatment, and replacement of tiles.

  20. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1990-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  1. Effect of ambient temperature and sodium bicarbonate supplementation on water and electrolyte balances in dry and lactating Holstein cows.

    PubMed

    Khelil-Arfa, H; Faverdin, P; Boudon, A

    2014-01-01

    The aim of this study was to quantify the effect of the interaction between 2 constant ambient temperatures [thermoneutrality (TN; 15°C) and high temperature (HT; 28°C)] and 2 levels of Na bicarbonate supplementation [calculated to provide diet Na contents of 0.20%DM (Na-) and 0.50%DM (Na+)] on water partitioning in dairy cows. Treatments were compared on 4 dry and 4mid-lactation Holstein cows according to 2 Latin squares (1 for each physiological stage) over the course of 4 periods of 15d. Diets consisted of a total mixed ration based on maize silage. Dry cows were restricted to their protein and energy requirements, whereas lactating cows were fed ad libitum. The daily average temperature-humidity index was 59.4 for TN and 73.2 for HT. Lactating and dry cows had higher vaginal temperatures at HT than at TN, but the increase was more pronounced in lactating cows (+1.05 vs. +0.12°C for vaginal temperature, respectively). Dry matter intake (DMI) of lactating cows decreased by 2.3kg/d at HT. Free water intake (FWI) and estimated volume of water lost to evaporation increased at HT in both lactating and dry cows; no interactions were observed between temperature and physiological stage. When expressed as a proportion of DMI, the increase in evaporation that occurred with increasing temperature was completely compensated for by an increase in FWI for both physiological stages. The urinary water excretion increased slightly at HT in lactating cows but not in dry cows, which may be related to the low chloride content of the offered diet. High Na supplementation increased DMI slightly in lactating cows, but milk yield was not affected. Sodium supplementation did not limit the decrease in DMI observed in lactating cows at HT; this observation is likely due to the high diet electrolyte balance of the offered diets. Sodium supplementation increased FWI in lactating cows and urinary flow in both physiological states. The interaction between ambient temperature and Na

  2. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-06

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  3. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-01

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  4. High temperature structural insulating material

    DOEpatents

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  5. Fertility of male and female broiler breeders following exposure to elevated ambient temperatures.

    PubMed

    McDaniel, C D; Bramwell, R K; Wilson, J L; Howarth, B

    1995-06-01

    Because elevated ambient temperatures decrease fertility, this study was designed to segregate the male and female contribution to heat stress infertility in broiler breeders. Eighty hens and 16 roosters at 21 wk of age were divided equally among two heat stress (S) and two control (C) temperature chambers. For a 10-wk pretreatment period, all birds were maintained at an ambient temperature of 21.1 C and 40% relative humidity. Following the pretreatment period, birds in the S chambers were acclimated for 1 wk at a constant temperature of 29.4 C after which the temperature in the S chambers was increased to 32.2 C for 8 wk. The temperature in the two C chambers was maintained at 21.1 C. Hens in each chamber were artificially inseminated on a weekly basis with 5 x 10(7) sperm per 50 microL from either C or S males. Egg production, semen volume, spermatocrit, and percentage dead sperm were similar during the acclimation period, even though body temperature was significantly elevated in S birds (41.8 vs 41.3 C). Sperm penetration of the perivitelline layer overlying the germinal disc (GD) was decreased in eggs from hens inseminated with semen from S males compared to eggs from hens inseminated with semen from C males (9.5 vs 23.4 sperm per GD). Following the acclimation period, body temperature remained elevated in the S birds compared to the C birds (42.2 vs 41.3 C). Also, egg production was depressed in the S vs C hens (55.8 vs 82.9%). Semen volume, spermatocrit, and percentage dead sperm were not affected by S treatment. However, when hens were inseminated with semen from S males, sperm penetration of the perivitelline layer overlying the GD and egg fertility were decreased compared to hens inseminated with semen from C males (5.4 vs 14.9 sperm per GD, 45.5 vs 73.8% fertility). In conclusion, the male bird appears to contribute more to heat stress infertility than the female.

  6. High Frequency Acoustic Channel Characterization for Propagation and Ambient Noise

    DTIC Science & Technology

    2007-09-30

    close collaboration with Michael Porter and Paul Hursky (HLS Research) with support from the ONR Ocean Acoustics Program and the ONR PLUSNet Project...Siderius, Chris Harrison and Michael Porter , “A passive fathometer for determining bottom depth and imaging seabed layering using ambient noise”, J...noise processing for estimation of seabed layering”, J. Acoust. Soc. Am., (2007) [submitted, refereed]. [8] Martin Siderius and Michael Porter , “Modeling

  7. High Frequency Acoustic Channel Characterization for Propagation and Ambient Noise

    DTIC Science & Technology

    2008-09-30

    has done in close collaboration with Michael Porter and Paul Hursky (HLS Research) also supported by ONR. We have also been collaborating with Steve... Michael Porter , “A passive fathometer technique for imaging seabed layering using ambient noise”, J. Acoust. Soc. Am., 120, 1315-1323, (September...Siderius and Michael Porter , “Modeling broadband ocean acoustic transmissions with time- varying sea surfaces”, J. Acoust. Soc. Am., 124 (1), 137-150

  8. High-Temperature Test Technology

    DTIC Science & Technology

    1987-03-01

    APR EDITION OF I JAN 73 IS OBSOLETE. Unclassif iedm"M SECURITY CLASSIFICATION OF THIS PAGE FORWORD The work documented in this report was performed...and turbine blades of jet engines. The objective of much of this work is a reliable, high- temperature, fast -response thermocouple which interferes as...In the latter case, durability, reasonable accuracy at high temperature and relatively small size are all important; fast response is perhaps less

  9. High temperature current mirror amplifier

    DOEpatents

    Patterson, III, Raymond B.

    1984-05-22

    A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg.

  10. The Very High Temperature Reactor

    SciTech Connect

    Hans D. Gougar; David A. Petti

    2011-06-01

    The High Temperature Reactor (HTR) and Very High Temperature Reactor (VHTR) are types of nuclear power plants that, as the names imply, operate at temperatures above those of the conventional nuclear power plants that currently generate electricity in the US and other countries. Like existing nuclear plants, heat generated from the fission of uranium or plutonium atoms is carried off by a working fluid and can be used generate electricity. The very hot working fluid also enables the VHTR to drive other industrial processes that require high temperatures not achievable by conventional nuclear plants (Figure 1). For this reason, the VHTR is being considered for non-electrical energy applications. The reactor and power conversion system are constructed using special materials that make a core meltdown virtually impossible.

  11. Effects of ambient temperature and relative humidity on the dynamics of salt distribution in porous media

    NASA Astrophysics Data System (ADS)

    Norouzi Rad, M.; Shokri, N.

    2011-12-01

    Understanding the physics of salt distribution in drying porous media is of relevance to various environmental and hydrological applications such as the soil salinization, terrestrial ecosystem functioning, microbiological activities in the vadose zone and structural damage to buildings, and historical monuments. Early stage of the evaporation process from saturated porous media is supplied by the capillary-induced liquid flow hydraulically connecting a receding drying front to surface (the so-called stage 1 evaporation). During stage 1, dissolved salt is transported by the capillary flow toward the evaporating surface where it accumulates, whereas diffusion (Brownian motion) tends to spread the salt and homogenize the concentrations in space. Relative humidity and ambient temperature limit the stage-1 evaporation and consequently influence the dynamics of salt distribution in porous media. The resulting interplay between convective and diffusive transport during evaporation is commonly quantified by the dimensionless Peclet number which is proportional to the evaporation rate. We have applied the convection-diffusion equation to describe the dynamics of salt distribution in drying porous media under different Peclet numbers. The predicted salt profiles were evaluated by a complete series of laboratory evaporation experiments using an environmental chamber where the relative humidity and temperature were accurately controlled. We have used sand with average particle size of 0.48 mm saturated with NaCl solution (1.25 Molal). The sand column was mounted on a digital balance connected to a computer to record the evaporation rate automatically. We studied dynamics of salt concentration at 30°C under relative humidity of 30%, 45% and 60% and also under the constant relative humidity of 45% at 30°C and 35°C . The experimentally-determined salt profiles were in a good agreement with the analytical and numerical predictions. Results revealed the preferential salt

  12. A Comparison of Low-Temperature and Ambient-Temperature SEM for Viewing Nematode Faces

    PubMed Central

    Carta, L. K.; Wergin, W. P.; Erbe, E. F.; Murphy, C. A.

    2003-01-01

    Faces of lesion nematodes Pratylenchus teres (populations RTB and JK) and P. zeae or the bacterivore Distolabrellus veechi were observed on frozen specimens with low-temperature scanning electron microscopy and as chemically fixed, critical-point dried specimens with conventional scanning electron microscopy. Amphidial secretions were preserved in chemically fixed but not cryofixed lesion nematodes. Overhanging liplets of chemically fixed D. veechi may be artifactual because they appeared as variably filled, mostly empty membranes when cryofixed. The diagnostically useful lips of the frozen lesion nematodes exhibited six sectors of variable prominence that were absent in chemically fixed specimens. This variability may be due to different degrees of muscle contraction captured during cryofixation, which occurs in milliseconds. This is the first evidence that rarely observed lip sectors in Pratylenchus may be something other than an artifact of shrinkage. PMID:19265978

  13. A hybrid downscaling procedure for estimating the vertical distribution of ambient temperature in local scale

    NASA Astrophysics Data System (ADS)

    Yiannikopoulou, I.; Philippopoulos, K.; Deligiorgi, D.

    2012-04-01

    The vertical thermal structure of the atmosphere is defined by a combination of dynamic and radiation transfer processes and plays an important role in describing the meteorological conditions at local scales. The scope of this work is to develop and quantify the predictive ability of a hybrid dynamic-statistical downscaling procedure to estimate the vertical profile of ambient temperature at finer spatial scales. The study focuses on the warm period of the year (June - August) and the method is applied to an urban coastal site (Hellinikon), located in eastern Mediterranean. The two-step methodology initially involves the dynamic downscaling of coarse resolution climate data via the RegCM4.0 regional climate model and subsequently the statistical downscaling of the modeled outputs by developing and training site-specific artificial neural networks (ANN). The 2.5ox2.5o gridded NCEP-DOE Reanalysis 2 dataset is used as initial and boundary conditions for the dynamic downscaling element of the methodology, which enhances the regional representivity of the dataset to 20km and provides modeled fields in 18 vertical levels. The regional climate modeling results are compared versus the upper-air Hellinikon radiosonde observations and the mean absolute error (MAE) is calculated between the four grid point values nearest to the station and the ambient temperature at the standard and significant pressure levels. The statistical downscaling element of the methodology consists of an ensemble of ANN models, one for each pressure level, which are trained separately and employ the regional scale RegCM4.0 output. The ANN models are theoretically capable of estimating any measurable input-output function to any desired degree of accuracy. In this study they are used as non-linear function approximators for identifying the relationship between a number of predictor variables and the ambient temperature at the various vertical levels. An insight of the statistically derived input

  14. Influence of Ambient Temperature on the CO2 Emitted With Exhaust Gases of Gasoline Vehicles

    NASA Astrophysics Data System (ADS)

    Chainikov, D.; Chikishev, E.; Anisimov, I.; Gavaev, A.

    2016-08-01

    This article focuses on the regulation of CO2 emitted in the exhaust gases of gasoline vehicles. Based on comparing the world practices of restrictive measures on greenhouse gas emissions with Russian legislation, we conclude that there is a need to adjust the limits of CO2 emission taking into account the negative impact of ambient temperature on CO2 emission. The climatic conditions of many countries stipulate the use of vehicles in temperatures below zero. At the same time, the existing regulations fully take into account the temperature features of the various countries, which casts doubt on the existence of uniform emission standards for all countries. Here, we conduct an experiment on one of the most popular cars in Russia: the Mitsubishi Lancer 9. We establish that lower temperatures are correlated with larger concentrations of CO2 in the exhaust gases. We draw a conclusion about the need to account for the actual operating conditions when establishing limit values on CO2 emissions of vehicles.

  15. Preferred ambient temperature for old and young men in summer and winter

    NASA Astrophysics Data System (ADS)

    Natsume, Keiko; Ogawa, Tokuo; Sugenoya, Junichi; Ohnishi, Norikazu; Imai, Kazuno

    1992-03-01

    To investigate the effects of age on thermal sensitivity, preferred ambient temperature ( T pref) was compared between old (71 76 years) and young (21 30 years) groups, each consisting of six male subjects in summer and winter. The air temperature ( T a) was set at either 20° C or 40° C at commencement. The subject was directed to adjust the T a for 45 min by manipulating a remote control switch to the level at which he felt most comfortable. In the older group, the T pref was significantly lower in trials starting at 20° C than that starting at 40° C in summer. The fluctuation of T pref (temperature difference between maximum and minimum T a during the last 10 min) was significantly wider in the older group in both summer and winter. Repetition of the same experiment on each subject showed a poorer reproducibility of T pref in the older group than in the younger group in summer. Tympanic and esophageal temperatures of the older group kept falling throughout the trial starting at 20° C in summer. These results suggest that thermal sensitivity is decreased with advancing age and that thermal perception in the elderly, especially to cold, is less sensitive in summer.

  16. Association between ambient temperature and blood pressure and blood pressure regulators: 1831 hypertensive patients followed up for three years.

    PubMed

    Chen, Qing; Wang, Jinwei; Tian, Jun; Tang, Xun; Yu, Canqing; Marshall, Roger J; Chen, Dafang; Cao, Weihua; Zhan, Siyan; Lv, Jun; Lee, Liming; Hu, Yonghua

    2013-01-01

    Several studies have suggested an association between ambient air temperature and blood pressure. However, this has not been reliably confirmed by longitudinal studies. Also, whether the reaction to temperature stimulation is modified by other factors such as antihypertensive medication is rarely investigated. The present study explores the relationship between ambient temperature and blood pressure, without and with antihypertensive medication, in a study of 1,831 hypertensive patients followed up for three years, in two or four weekly check ups, accumulating 62,452 follow-up records. Both baseline and follow-up blood pressure showed an inverse association with ambient temperature, which explained 32.4% and 65.6% of variation of systolic blood pressure and diastolic blood pressure (P<0.05) respectively. The amplitude of individual blood pressure fluctuation with temperature throughout a year (a 29 degrees centigrade range) was 9.4/7.3 mmHg. Medication with angiotensin converting enzyme inhibitor benazepril attenuated the blood pressure fluctuation by 2.4/1.3 mmHg each year, though the inverse association of temperature and blood pressure remained. Gender, drinking behavior and body mass index were also found to modify the association between temperature and diastolic blood pressure. The results indicate that ambient temperature may negatively regulate blood pressure. Hypertensive patients should monitor and treat blood pressure more carefully in cold days, and it could be especially important for the males, thinner people and drinkers.

  17. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... during which reference temperature and flow rate measurements shall be made at intervals not to exceed 5... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient air temperature... definition. Sample flow rate means the quantitative volumetric flow rate of the air stream caused by...

  18. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... during which reference temperature and flow rate measurements shall be made at intervals not to exceed 5... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient air temperature...) Technical definition. Sample flow rate means the quantitative volumetric flow rate of the air stream...

  19. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... during which reference temperature and flow rate measurements shall be made at intervals not to exceed 5... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient air temperature... definition. Sample flow rate means the quantitative volumetric flow rate of the air stream caused by...

  20. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... during which reference temperature and flow rate measurements shall be made at intervals not to exceed 5... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient air temperature... definition. Sample flow rate means the quantitative volumetric flow rate of the air stream caused by...

  1. Model Study of the Influence of Ambient Temperature and Installation Types on Surface Temperature Measurement by Using a Fiber Bragg Grating Sensor.

    PubMed

    Liu, Yi; Zhang, Jun

    2016-07-01

    Surface temperature is an important parameter in clinical diagnosis, equipment state control, and environmental monitoring fields. The Fiber Bragg Grating (FBG) temperature sensor possesses numerous significant advantages over conventional electrical sensors, thus it is an ideal choice to achieve high-accuracy surface temperature measurements. However, the effects of the ambient temperature and installation types on the measurement of surface temperature are often overlooked. A theoretical analysis is implemented and a thermal transfer model of a surface FBG sensor is established. The theoretical and simulated analysis shows that both substrate strain and the temperature difference between the fiber core and hot surface are the most important factors which affect measurement accuracy. A surface-type temperature standard setup is proposed to study the measurement error of the FBG temperature sensor. Experimental results show that there are two effects influencing measurement results. One is the "gradient effect". This results in a positive linear error with increasing surface temperature. Another is the "substrate effect". This results in a negative non-linear error with increasing surface temperature. The measurement error of the FBG sensor with single-ended fixation are determined by the gradient effect and is a linear error. It is not influenced by substrate expansion. Thus, it can be compensated easily. The measurement errors of the FBG sensor with double-ended fixation are determined by the two effects and the substrate effect is dominant. The measurement error change trend of the FBG sensor with fully-adhered fixation is similar to that with double-ended fixation. The adhesive layer can reduce the two effects and measurement error. The fully-adhered fixation has lower error, however, it is easily affected by substrate strain. Due to its linear error and strain-resistant characteristics, the single-ended fixation will play an important role in the FBG sensor

  2. Model Study of the Influence of Ambient Temperature and Installation Types on Surface Temperature Measurement by Using a Fiber Bragg Grating Sensor

    PubMed Central

    Liu, Yi; Zhang, Jun

    2016-01-01

    Surface temperature is an important parameter in clinical diagnosis, equipment state control, and environmental monitoring fields. The Fiber Bragg Grating (FBG) temperature sensor possesses numerous significant advantages over conventional electrical sensors, thus it is an ideal choice to achieve high-accuracy surface temperature measurements. However, the effects of the ambient temperature and installation types on the measurement of surface temperature are often overlooked. A theoretical analysis is implemented and a thermal transfer model of a surface FBG sensor is established. The theoretical and simulated analysis shows that both substrate strain and the temperature difference between the fiber core and hot surface are the most important factors which affect measurement accuracy. A surface-type temperature standard setup is proposed to study the measurement error of the FBG temperature sensor. Experimental results show that there are two effects influencing measurement results. One is the “gradient effect”. This results in a positive linear error with increasing surface temperature. Another is the “substrate effect”. This results in a negative non-linear error with increasing surface temperature. The measurement error of the FBG sensor with single-ended fixation are determined by the gradient effect and is a linear error. It is not influenced by substrate expansion. Thus, it can be compensated easily. The measurement errors of the FBG sensor with double-ended fixation are determined by the two effects and the substrate effect is dominant. The measurement error change trend of the FBG sensor with fully-adhered fixation is similar to that with double-ended fixation. The adhesive layer can reduce the two effects and measurement error. The fully-adhered fixation has lower error, however, it is easily affected by substrate strain. Due to its linear error and strain-resistant characteristics, the single-ended fixation will play an important role in the FBG

  3. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi.

    1989-10-03

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

  4. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi

    1989-01-01

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

  5. High temperature electronic gain device

    DOEpatents

    McCormick, J. Byron; Depp, Steven W.; Hamilton, Douglas J.; Kerwin, William J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube.

  6. High temperature Seebeck coefficient metrology

    SciTech Connect

    Martin, J.; Tritt, T.; Uher, C.

    2010-12-15

    We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

  7. Gallium phosphide high temperature diodes

    NASA Technical Reports Server (NTRS)

    Chaffin, R. J.; Dawson, L. R.

    1981-01-01

    High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

  8. Short-term respiratory effects of polluted ambient air: a laboratory study of volunteers in a high-oxidant community

    SciTech Connect

    Linn, W.S.; Jones, M.P.; Bachmayer, E.A.; Spier, C.E.; Mazur, S.F.; Avol, E.L.; Hackney, J.D.

    1980-02-01

    To investigate short-term health effects of community air pollution directly, researchers developed a mobile laboratory allowing blind exposures of volunteers to polluted ambient air and to purified air at similar temperature and humidity. Subjects from the surrounding area were studied at Duarte, California, a Los Angeles suburb subject to frequent photochemical oxidant pollution. Each was exposed to a close approximation of outdoor ambient air for 2 h with intermittent light exercise. Lung function and symptoms were evaluated pre- and post-exposure. A control study took place several weeks later. Mean ambient air exposure concentrations were near 0.22 ppM for ozone and 200 micrograms/m3 for total suspended particulate. Ambient air exposures were associated with small significant losses in forced expiratory performance and total lung capacity. The responses of asthmatic and normal subjects were generally not significantly different, possibly because many normal subjects had a history of allergy and appeared atypically reactive to respiratory insults. In the normal subjects, a small significant increase in reported symptoms was seen with ambient air exposures compared with the control. In the asthmatics, the increase was not significant. Over-all, only slight effects attributable to exposure were found, even though a severely polluted area and a presumed high-risk population were chosen for study.

  9. Permeability of Molecular Hydrogen and Water Vapor Through Butyl Rubber at Ambient Temperature

    SciTech Connect

    Zeigler, K.

    1992-04-09

    The preparation of the Safety Analysis Report for the 233-H Replacement Tritium Facility (RTF) requires permeation constants of hydrogen isotopes through butyl rubber, to estimate possible worker exposure given a certain level of tritium in the confinement gloveboxes. Literature values of the permeability constants for hydrogen isotopes and water vapor through butyl rubber at ambient temperature (22-25 C) have been converted to common units and are tabulated (Tables I and II). Permeation rates of tritiated species are the same as that of protium species, within experimental error. Thus, molecular protium and normal water vapor data serve to estimate tritium permeation rates. Because of vendor to vendor variability of permeability, especially of water vapor, vendor measurements of water vapor permeability should continue to be used to estimate permeation in SRS processes.

  10. Permeability of Molecular Hydrogen and Water Vapor Through Butyl Rubber at Ambient Temperature

    SciTech Connect

    Clark, Elliot A.

    1992-04-09

    The preparation of the Safety Analysis Report for the 233-H Replacement Tritium Facility (RTF) requires permeation constants of hydrogen isotopes through butyl rubber, to estimate possible worker exposure given a certain level of tritium in the confinement gloveboxes. Literature values of the permeability constants for hydrogen isotopes and water vapor through butyl rubber at ambient temperature (22-25 C) have been converted to common units and are tabulated (Tables I and II). Permeation rates of tritiated species are the same as that of protium species, within experimental error. Thus, molecular protium and normal water vapor data serve to estimate tritium permeation rates. Because of vendor-to-vendor variability of permeability, especially of water vapor, vendor measurements of water vapor permeability should continue to be used to estimate permeation in SRS processes.

  11. Atomic resolution structure of serine protease proteinase K at ambient temperature

    PubMed Central

    Masuda, Tetsuya; Suzuki, Mamoru; Inoue, Shigeyuki; Song, Changyong; Nakane, Takanori; Nango, Eriko; Tanaka, Rie; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Yabashi, Makina; Mikami, Bunzo; Nureki, Osamu; Numata, Keiji; Iwata, So; Sugahara, Michihiro

    2017-01-01

    Atomic resolution structures (beyond 1.20 Å) at ambient temperature, which is usually hampered by the radiation damage in synchrotron X-ray crystallography (SRX), will add to our understanding of the structure-function relationships of enzymes. Serial femtosecond crystallography (SFX) has attracted surging interest by providing a route to bypass such challenges. Yet the progress on atomic resolution analysis with SFX has been rather slow. In this report, we describe the 1.20 Å resolution structure of proteinase K using 13 keV photon energy. Hydrogen atoms, water molecules, and a number of alternative side-chain conformations have been resolved. The increase in the value of B-factor in SFX suggests that the residues and water molecules adjacent to active sites were flexible and exhibited dynamic motions at specific substrate-recognition sites. PMID:28361898

  12. Ceramic coating of metal by laser heat treatment at ambient pressure and temperature

    NASA Astrophysics Data System (ADS)

    Picouet, Pierre A.; McStay, Daniel; Hunter, Catherine; Tonge, Kenneth

    2000-02-01

    Initial results for a new laser based procedure to make ceramic coatings on ferrous metals are described. The procedure is performed at ambient temperature and pressure to avoid the use of a vacuum chamber. An Nd:YAG laser beam (1064 nm) coupled to a mechanical scanner is used to produce coating. The coating precursor materials are sprayed onto the metal sample before the laser-generated heat treatment. A jet of argon gas is used to avoid oxidation of the metallic substrate. The principal ingredients of the coating precursor are sodium tetraborate and a natural clay mineral. The product is a glassy ceramic. The product has been characterized by scanning electron microscopy, optical microscopy and hardness and adhesion tests. The results indicate that the surface material is a micrometric, single layer which adheres to the metal surface.

  13. Synthesis of ammonia directly from air and water at ambient temperature and pressure

    PubMed Central

    Lan, Rong; Irvine, John T. S.; Tao, Shanwen

    2013-01-01

    The N≡N bond (225 kcal mol−1) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N2 separation and H2 production stages. A maximum ammonia production rate of 1.14 × 10−5 mol m−2 s−1 has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future. PMID:23362454

  14. Synthesis of ammonia directly from air and water at ambient temperature and pressure.

    PubMed

    Lan, Rong; Irvine, John T S; Tao, Shanwen

    2013-01-01

    The N≡N bond (225 kcal mol⁻¹) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N₂ separation and H₂ production stages. A maximum ammonia production rate of 1.14 × 10⁻⁵ mol m⁻² s⁻¹ has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

  15. Atomic resolution structure of serine protease proteinase K at ambient temperature.

    PubMed

    Masuda, Tetsuya; Suzuki, Mamoru; Inoue, Shigeyuki; Song, Changyong; Nakane, Takanori; Nango, Eriko; Tanaka, Rie; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Yabashi, Makina; Mikami, Bunzo; Nureki, Osamu; Numata, Keiji; Iwata, So; Sugahara, Michihiro

    2017-03-31

    Atomic resolution structures (beyond 1.20 Å) at ambient temperature, which is usually hampered by the radiation damage in synchrotron X-ray crystallography (SRX), will add to our understanding of the structure-function relationships of enzymes. Serial femtosecond crystallography (SFX) has attracted surging interest by providing a route to bypass such challenges. Yet the progress on atomic resolution analysis with SFX has been rather slow. In this report, we describe the 1.20 Å resolution structure of proteinase K using 13 keV photon energy. Hydrogen atoms, water molecules, and a number of alternative side-chain conformations have been resolved. The increase in the value of B-factor in SFX suggests that the residues and water molecules adjacent to active sites were flexible and exhibited dynamic motions at specific substrate-recognition sites.

  16. Multipole electrodynamic ion trap geometries for microparticle confinement under standard ambient temperature and pressure conditions

    NASA Astrophysics Data System (ADS)

    Mihalcea, Bogdan M.; Giurgiu, Liviu C.; Stan, Cristina; Vişan, Gina T.; Ganciu, Mihai; Filinov, Vladimir; Lapitsky, Dmitry; Deputatova, Lidiya; Syrovatka, Roman

    2016-03-01

    Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in case of multipole linear Paul trap geometries, operating under standard ambient temperature and pressure conditions. An 8- and 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap is mapped using the electrolytic tank method. Particle dynamics is simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.

  17. Handheld low-temperature plasma probe for portable "point-and-shoot" ambient ionization mass spectrometry.

    PubMed

    Wiley, Joshua S; Shelley, Jacob T; Cooks, R Graham

    2013-07-16

    We describe a handheld, wireless low-temperature plasma (LTP) ambient ionization source and its performance on a benchtop and a miniature mass spectrometer. The source, which is inexpensive to build and operate, is battery-powered and utilizes miniature helium cylinders or air as the discharge gas. Comparison of a conventional, large-scale LTP source against the handheld LTP source, which uses less helium and power than the large-scale version, revealed that the handheld source had similar or slightly better analytical performance. Another advantage of the handheld LTP source is the ability to quickly interrogate a gaseous, liquid, or solid sample without requiring any setup time. A small, 7.4-V Li-polymer battery is able to sustain plasma for 2 h continuously, while the miniature helium cylinder supplies gas flow for approximately 8 continuous hours. Long-distance ion transfer was achieved for distances up to 1 m.

  18. The influence of ambient temperature and thermal acclimation on hearing in a eurythermal and a stenothermal otophysan fish.

    PubMed

    Wysocki, Lidia Eva; Montey, Karen; Popper, Arthur N

    2009-10-01

    Being ectothermic, fish body temperature generally depends on ambient water temperature. Thus, ambient temperature might affect various sensory systems, including hearing, as a result of metabolic and physiological processes. However, the maintenance of sensory functions in a changing environment may be crucial for an animal's survival. Many fish species rely on hearing for acoustic orientation and communication. In order to investigate the influence of temperature on the auditory system, channel catfish Ictalurus punctatus was chosen as a model for a eurytherm species and the tropical catfish Pimelodus pictus as a model for a stenotherm fish. Hearing sensitivity was measured with animals acclimated or unacclimated to different water temperatures. Ambient water temperature significantly influenced hearing thresholds and the shape of auditory evoked potentials, especially at higher frequencies in I. punctatus. Hearing sensitivity of I. punctatus was lowest at 10 degrees C and increased by up to 36 dB between 10 degrees C and 26 degrees C. Significant differences were also revealed between acclimated and unacclimated animals after an increase in water temperature but not a decrease. By contrast, differences in hearing thresholds were smaller in P. pictus, even if a similar temperature difference (8 degrees C) was considered. However, P. pictus showed a similar trend as I. punctatus in exhibiting higher hearing sensitivity at the highest tested temperature, especially at the highest frequency tested. The results therefore suggest that the functional temperature dependence of sensory systems may differ depending upon whether a species is physiologically adapted to tolerate a wide or narrow temperature range.

  19. Effect of ambient temperature on species lumping for total organic gases in gasoline exhaust emissions

    NASA Astrophysics Data System (ADS)

    Roy, Anirban; Choi, Yunsoo

    2017-03-01

    Volatile organic compound (VOCs) emissions from sources often need to be compressed or "lumped" into species classes for use in emissions inventories intended for air quality modeling. This needs to be done to ensure computational efficiency. The lumped profiles are usually reported for one value of ambient temperature. However, temperature-specific detailed profiles have been constructed in the recent past - the current study investigates how the lumping of species from those profiles into different atmospheric chemistry mechanisms is affected by temperature, considering three temperatures (-18 °C, -7 °C and 24 °C). The mechanisms considered differed on the assumptions used for lumping: CB05 (carbon bond type), SAPRC (ozone formation potential) and RACM2 (molecular surrogate and reactivity weighting). In this space, four sub-mechanisms for SAPRC were considered. Scaling factors were developed for each lumped model species and mechanism in terms of moles of lumped species per unit mass. Species which showed a direct one-to-one mapping (SAPRC/RACM2) reported scaling factors that were unchanged across mechanisms. However, CB05 showed different trends since one compound often is mapped onto multiple model species, out of which the paraffinic double bond (PAR) is predominant. Temperature-dependent parameterizations for emission factors pertaining to each lumped species class and mechanism were developed as part of the study. Here, the same kind of model species showed varying lumping parameters across the different mechanisms. These differences could be attributed to differing approaches in lumping. The scaling factors and temperature-dependent parameterizations could be used to update emissions inventories such as MOVES or SMOKE for use in chemical transport modeling.

  20. The Influence of Ambient Temperature on the Susceptibility of Aedes aegypti (Diptera: Culicidae) to the Pyrethroid Insecticide Permethrin.

    PubMed

    Whiten, Shavonn R; Peterson, Robert K D

    2016-01-01

    Insecticides are the most common strategy used for the management of mosquitoes. Changes in ambient temperature can alter the toxicity of insecticides to ectothermic organisms. Studies show organophosphate insecticides exhibit a positive correlation between ambient temperature and mortality for many insect species, and carbamate insecticides exhibit a slightly negative correlation between ambient temperature and mortality. Pyrethroid insecticides exhibit a distinctly negative correlation between increasing ambient temperature and mortality for insects. However, this relationship has not been systematically studied for adult mosquitoes. Therefore, we examined the influence of temperature on the susceptibility of adult Aedes aegypti L. (Diptera: Culicidae) when exposed to permethrin. The median lethal concentration, LC50, was estimated for adult Ae. aegypti when exposed to eight concentrations of permethrin (ranging from 0.06–0.58 ng/cm2) at each of the following temperatures—16, 23, 26, 30, 32, and 34C—for 24 h in bottle assays. The estimated LC50 for each temperature was 0.26, 0.36, 0.36, 0.45, 0.27, and 0.31 ng/cm2, respectively. Results indicated a negative correlation between temperature and mortality from 16 to 30C, a positive correlation between temperature and mortality from 30 to 32C, and a negative correlation between temperature and mortality from 32 to 34C. If mosquito populations are expanding in space and time because of increased ambient temperatures and cannot be managed as effectively with pyrethroids, the spread of mosquito-borne diseases may pose considerable additional risk to public health.

  1. High-Temperature Optical Sensor

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  2. High Temperature Transparent Furnace Development

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.

    1997-01-01

    This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

  3. Interface high-temperature superconductivity

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  4. Effects of temperature, algae biomass and ambient nutrient on the absorption of dissolved nitrogen and phosphate by Rhodophyte Gracilaria asiatica

    NASA Astrophysics Data System (ADS)

    Du, Rongbin; Liu, Liming; Wang, Aimin; Wang, Yongqiang

    2013-03-01

    Gracilaria asiatica, being highly efficient in nutrient absorption, is cultivated in sea cucumber ponds to remove nutrients such as nitrogen and phosphate. It was cultured in a laboratory simulating field conditions, and its nutrient absorption was measured to evaluate effects of environmental conditions. Ammonia nitrogen (AN), nitrate nitrogen (NN), total inorganic nitrogen (TIN), and soluble reactive phosphorus (SRP) uptake rate and removal efficiency were determined in a 4×2 factorial design experiment in water temperatures ( T) at 15°C and 25°C, algae biomass (AB) at 0.5 g/L and 1.0 g/L, total inorganic nitrogen (TIN) at 30 μmol/L and 60 μmol/L, and soluble reactive phosphorus (SRP) at 3 and 6 μmol/L. AB and ambient TIN or SRP levels significantly affected uptake rate and removal efficiency of AN, NN, TIN, and SRP ( P< 0.001). G. asiatica in AB of 0.5 g/L showed higher uptake rate and lower removal efficiency relative to that with AB of 1.0 g/L. Nitrogen and phosphorus uptake rate rose with increasing ambient nutrient concentrations; nutrient removal efficiency decreased at higher environmental nutrient concentrations. The algae preferred to absorb AN to NN. Uptake rates of AN, NN, and SRP were significantly affected by temperature ( P < 0.001); uptake rate was higher for the 25°C group than for the 15°C group at the initial experiment stage. Only the removal efficiency of AN and SRP showed a significant difference between the two temperature groups ( P< 0.01). The four factors had significant interactive effects on absorption of N and P, implying that G. asiatica has great bioremedial potential in sea cucumber culture ponds.

  5. Structural and dynamical properties of water under ambient and high-pressure conditions

    NASA Astrophysics Data System (ADS)

    Schwegler, Eric

    2005-03-01

    The structural and dynamical properties of water are investigated with ab initio molecular dynamics. A series of density functional theory based simulations is presented where the effect of temperature at ambient density is explored in order to demonstrate the level of accuracy that can be achieved, and the open challenges that remain in describing liquid water [1,2]. In addition to water at ambient density, the effect of high-pressures, in a regime where molecular dissociation plays a dominant role, is explored for both liquid water and the high-pressure phases of ice. In particular, large-scale two phase simulations of water are used to determine the melting temperature of water in the range of 10 to 50 GPa [3]. This work was performed under the auspices of the US Department of Energy by the University of California at the LLNL under contract no W-7405-Eng-48. * In collaboration with Jeffery C. Grossman, Francois Gygi and Giulia Galli. [1] ``Towards an assessment of the accuracy of density functional theory for first principles simulations of water'', J. Grossman, E. Schwegler, E. Draeger, F. Gygi and G. Galli, J. Chem. Phys. 120, 300 (2004); and ``Towards an assessment of the accuracy of density functional theory for first principles simulations of water II'', E. Schwegler, J. Grossman, F. Gygi and G. Galli, J. Chem. Phys. 121, 5400 (2004). [2] ``First principles simulations of rigid water'', M. Allesch, E. Schwegler, F. Gygi and G.Galli, J. Chem. Phys. 120, 5192 (2004). [3] ``Dissociation of water under pressure'', E. Schwegler, G. Galli, F. Gygi, and R. Hood, Phys. Rev. Lett. 87, 265501 (2001); and E. Schwegler, F. Gygi and G. Galli (manuscript in preparation).

  6. Importance of sample form and surface temperature for analysis by ambient plasma mass spectrometry (PADI).

    PubMed

    Salter, Tara La Roche; Bunch, Josephine; Gilmore, Ian S

    2014-09-16

    Many different types of samples have been analyzed in the literature using plasma-based ambient mass spectrometry sources; however, comprehensive studies of the important parameters for analysis are only just beginning. Here, we investigate the effect of the sample form and surface temperature on the signal intensities in plasma-assisted desorption ionization (PADI). The form of the sample is very important, with powders of all volatilities effectively analyzed. However, for the analysis of thin films at room temperature and using a low plasma power, a vapor pressure of greater than 10(-4) Pa is required to achieve a sufficiently good quality spectrum. Using thermal desorption, we are able to increase the signal intensity of less volatile materials with vapor pressures less than 10(-4) Pa, in thin film form, by between 4 and 7 orders of magnitude. This is achieved by increasing the temperature of the sample up to a maximum of 200 °C. Thermal desorption can also increase the signal intensity for the analysis of powders.

  7. "Green" High-Temperature Polymers

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  8. High temperature solar thermal technology

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

    1980-01-01

    Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

  9. High temperature superconductor current leads

    DOEpatents

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  10. High temperature solar thermal technology

    NASA Astrophysics Data System (ADS)

    Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

    1980-11-01

    Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

  11. High temperature current mirror amplifier

    DOEpatents

    Patterson, R.B. III.

    1984-05-22

    Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. 2 figs.

  12. High temperature superconductor current leads

    DOEpatents

    Hull, J.R.; Poeppel, R.B.

    1995-06-20

    An electrical lead is disclosed having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths. 9 figs.

  13. High temperature polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Serafini, Tito T. (Editor)

    1987-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) Characterization; (4) environmental effects; and (5) applications.

  14. High Temperature Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    1985-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) characterization; (4) environmental effects; and (5) applications.

  15. Cold-start emissions of modern passenger cars at different low ambient temperatures and their evolution over vehicle legislation categories

    NASA Astrophysics Data System (ADS)

    Weilenmann, Martin; Favez, Jean-Yves; Alvarez, Robert

    The emissions of modern gasoline and diesel passenger cars are reduced by catalysts except in cold-starting. Since catalysts require a certain temperature (typically above 300 °C) to work to full efficiency, emissions are significantly higher during the warm-up phase of the car. The duration of this period and the emissions produced depend on the ambient temperature as well as on the initial temperature of the car's propulsion systems. The additional emissions during a warm-up phase, known as "cold-start extra emissions" (CSEEs) for emission inventory modelling, are mostly assessed by emission measurements at an ambient temperature of 23 °C. However, in many European countries average ambient temperatures are below 23 °C. This necessitates emission measurements at lower temperatures in order to model and assess cold-start emissions for real-world temperature conditions. This paper investigates the influence of regulated pollutants and CO 2 emissions of recent gasoline and diesel car models (Euro-4 legislation) at different ambient temperatures, 23, -7 and -20 °C. We present a survey and model of the evolution of cold-start emissions as a function of different car generations (pre-Euro-1 to Euro-4 legislations). In addition the contribution of CSEEs to total fleet running emissions is shown to highlight their increasing importance. For gasoline cars, it turns out that in average real-world driving the majority of the CO (carbon monoxide) and HC (hydrocarbon) total emissions are due to cold-start extra emissions. Moreover, the cold-start emissions increase considerably at lower ambient temperatures. In contrast, cold-start emissions of diesel cars are significantly lower than those of gasoline cars. Furthermore, the transition from Euro-3 to Euro-4 gasoline vehicles shows a trend for a smaller decline for cold-start extra emissions than for legislative limits. Particle and NO x emission of cold-starts are less significant.

  16. Nonlinear plasmonics at high temperatures

    NASA Astrophysics Data System (ADS)

    Sivan, Yonatan; Chu, Shi-Wei

    2017-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  17. Nonlinear plasmonics at high temperatures

    NASA Astrophysics Data System (ADS)

    Sivan, Yonatan; Chu, Shi-Wei

    2016-10-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  18. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1991-01-01

    A high temperature turbine engine includes a rotor portion having axially stacked adjacent ceramic rotor parts. A ceramic/ceramic joint structure transmits torque between the rotor parts while maintaining coaxial alignment and axially spaced mutually parallel relation thereof despite thermal and centrifugal cycling.

  19. High-temperature plasma physics

    SciTech Connect

    Furth, H.P.

    1988-03-01

    Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics.

  20. Amorphous/crystalline silicon interface passivation: Ambient-temperature dependence and implications for solar cell performance

    DOE PAGES

    Seif, Johannes P.; Krishnamani, Gopal; Demaurex, Benedicte; ...

    2015-03-02

    Silicon heterojunction (SHJ) solar cells feature amorphous silicon passivation films, which enable very high voltages. We report how such passivation increases with operating temperature for amorphous silicon stacks involving doped layers and decreases for intrinsic-layer-only passivation. We discuss the implications of this phenomenon on the solar cell's temperature coefficient, which represents an important figure-of-merit for the energy yield of devices deployed in the field. We show evidence that both open-circuit voltage (Voc) and fill factor (FF) are affected by these variations in passivation and quantify these temperature-mediated effects, compared with those expected from standard diode equations. We confirm that devicesmore » with high Voc values at 25°C show better high-temperature performance. Thus, we also argue that the precise device architecture, such as the presence of charge-transport barriers, may affect the temperature-dependent device performance as well.« less

  1. Amorphous/crystalline silicon interface passivation: Ambient-temperature dependence and implications for solar cell performance

    SciTech Connect

    Seif, Johannes P.; Krishnamani, Gopal; Demaurex, Benedicte; Ballif, Christophe; Wolf, Stefaan De

    2015-03-02

    Silicon heterojunction (SHJ) solar cells feature amorphous silicon passivation films, which enable very high voltages. We report how such passivation increases with operating temperature for amorphous silicon stacks involving doped layers and decreases for intrinsic-layer-only passivation. We discuss the implications of this phenomenon on the solar cell's temperature coefficient, which represents an important figure-of-merit for the energy yield of devices deployed in the field. We show evidence that both open-circuit voltage (Voc) and fill factor (FF) are affected by these variations in passivation and quantify these temperature-mediated effects, compared with those expected from standard diode equations. We confirm that devices with high Voc values at 25°C show better high-temperature performance. Thus, we also argue that the precise device architecture, such as the presence of charge-transport barriers, may affect the temperature-dependent device performance as well.

  2. Containerless high temperature property measurements

    NASA Technical Reports Server (NTRS)

    Nordine, Paul C.; Weber, J. K. Richard; Krishnan, Shankar; Anderson, Collin D.

    1991-01-01

    Containerless processing in the low gravity environment of space provides the opportunity to increase the temperature at which well controlled processing of and property measurements on materials is possible. This project was directed towards advancing containerless processing and property measurement techniques for application to materials research at high temperatures in space. Containerless high temperature material property studies include measurements of the vapor pressure, melting temperature, optical properties, and spectral emissivities of solid boron. The reaction of boron with nitrogen was also studied by laser polarimetric measurement of boron nitride film growth. The optical properties and spectral emissivities were measured for solid and liquid silicon, niobium, and zirconium; liquid aluminum and titanium; and liquid Ti-Al alloys of 5 to 60 atomic pct. titanium. Alternative means for noncontact temperature measurement in the absence of material emissivity data were evaluated. Also, the application of laser induced fluorescence for component activity measurements in electromagnetic levitated liquids was studied, along with the feasibility of a hybrid aerodynamic electromagnetic levitation technique.

  3. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  4. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  5. Test Standard Developed for Determining the Slow Crack Growth of Advanced Ceramics at Ambient Temperature

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Salem, Jonathan A.

    1998-01-01

    The service life of structural ceramic components is often limited by the process of slow crack growth. Therefore, it is important to develop an appropriate testing methodology for accurately determining the slow crack growth design parameters necessary for component life prediction. In addition, an appropriate test methodology can be used to determine the influences of component processing variables and composition on the slow crack growth and strength behavior of newly developed materials, thus allowing the component process to be tailored and optimized to specific needs. At the NASA Lewis Research Center, work to develop a standard test method to determine the slow crack growth parameters of advanced ceramics was initiated by the authors in early 1994 in the C 28 (Advanced Ceramics) committee of the American Society for Testing and Materials (ASTM). After about 2 years of required balloting, the draft written by the authors was approved and established as a new ASTM test standard: ASTM C 1368-97, Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature. Briefly, the test method uses constant stress-rate testing to determine strengths as a function of stress rate at ambient temperature. Strengths are measured in a routine manner at four or more stress rates by applying constant displacement or loading rates. The slow crack growth parameters required for design are then estimated from a relationship between strength and stress rate. This new standard will be published in the Annual Book of ASTM Standards, Vol. 15.01, in 1998. Currently, a companion draft ASTM standard for determination of the slow crack growth parameters of advanced ceramics at elevated temperatures is being prepared by the authors and will be presented to the committee by the middle of 1998. Consequently, Lewis will maintain an active leadership role in advanced ceramics standardization within ASTM

  6. Acoustic testing of high temperature panels

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Clevenson, Sherman A.; Powell, Clemans A.; Daniels, Edward F.

    1990-01-01

    Results are presented of a series of thermal-acoustic tests conducted on the NASA Langley Research Center Thermal-Acoustic Test Apparatus to (1) investigate techniques for obtaining strain measurements on metallic and carbon-carbon materials at elevated temperature; (2) document the dynamic strain response characteristics of several superalloy honeycomb thermal protection system panels at elevated temperatures of up to 1200 F; and (3) determine the strain response and sonic fatigue behavior of four carbon-carbon panels at both ambient and elevated temperatures. A second study tested four carbon-carbon panels to document panel dynamic response characteristics at ambient and elevated temperature, determine time to failure and faliure modes, and collect continuous strain data up to panel failure. Strain data are presented from both types of panels, and problems encountered in obtaining reliable strain data on the carbon-carbon panels are described. The failure modes of the carbon-carbon panels are examined.

  7. LX-17 Deflagration at High Pressures and Temperatures

    SciTech Connect

    Koerner, J; Maienschein, J; Black, K; DeHaven, M; Wardell, J

    2006-10-23

    We measure the laminar deflagration rate of LX-17 (92.5 wt% TATB, 7.5 wt% Kel-F 800) at high pressure and temperature in a strand burner, thereby obtaining reaction rate data for prediction of thermal explosion violence. Simultaneous measurements of flame front time-of-arrival and temporal pressure history allow for the direct calculation of deflagration rate as a function of pressure. Additionally, deflagrating surface areas are calculated in order to provide quantitative insight into the dynamic surface structure during deflagration and its relationship to explosion violence. Deflagration rate data show that LX-17 burns in a smooth fashion at ambient temperature and is represented by the burn rate equation B = 0.2P{sup 0.9}. At 225 C, deflagration is more rapid and erratic. Dynamic deflagrating surface area calculations show that ambient temperature LX-17 deflagrating surface areas remain near unity over the pressure range studied.

  8. Method for high temperature mercury capture from gas streams

    DOEpatents

    Granite, E.J.; Pennline, H.W.

    2006-04-25

    A process to facilitate mercury extraction from high temperature flue/fuel gas via the use of metal sorbents which capture mercury at ambient and high temperatures. The spent sorbents can be regenerated after exposure to mercury. The metal sorbents can be used as pure metals (or combinations of metals) or dispersed on an inert support to increase surface area per gram of metal sorbent. Iridium and ruthenium are effective for mercury removal from flue and smelter gases. Palladium and platinum are effective for mercury removal from fuel gas (syngas). An iridium-platinum alloy is suitable for metal capture in many industrial effluent gas streams including highly corrosive gas streams.

  9. Real-World Emission of Particles from Vehicles: Volatility and the Effects of Ambient Temperature.

    PubMed

    Wang, Jonathan M; Jeong, Cheol-Heon; Zimmerman, Naomi; Healy, Robert M; Hilker, Nathan; Evans, Greg J

    2017-04-04

    A majority of the ultrafine particles observed in real-world conditions are systematically excluded from many measurements that help to guide regulation of vehicle emissions. To investigate the impact of this exclusion, coincident near-road particle number (PN) emission factors were quantified up- and downstream of a thermodenuder during two seasonal month-long campaigns with wide-ranging ambient temperatures (-19 to +30 °C) to determine the volatile fraction of particles. During colder temperatures (<0 °C), the volatile fraction of particles was 94%, but decreased to 85% during warmer periods (>20 °C). Additionally, mean PN emission factors were a factor of 3.8 higher during cold compared to warm periods. On the basis of 130 000 vehicle plumes including three additional campaigns, fleet mean emission factors were calculated for PN (8.5 × 10(14) kg-fuel(-1)), black carbon (37 mg kg-fuel(-1)), organic aerosol (51 mg kg-fuel(-1)), and particle-bound polycyclic aromatic hydrocarbons (0.7 mg kg-fuel(-1)). These findings demonstrate that significant differences exist between particles in thermally treated vehicle exhaust as compared to in real-world vehicle plumes to which populations in near-road environments are actually exposed. Furthermore, the magnitude of these differences are dependent upon season and may be more extreme in colder climates.

  10. Humidity-resistant ambient-temperature solid-electrolyte amperometric sensing apparatus

    DOEpatents

    Zaromb, Solomon

    1994-01-01

    Apparatus and methods for detecting selected chemical compounds in air or other gas streams at room or ambient temperature includes a liquid-free humidity-resistant amperometric sensor comprising a sensing electrode and a counter and reference electrode separated by a solid electrolyte. The sensing electrode preferably contains a noble metal, such as Pt black. The electrolyte is water-free, non-hygroscopic, and substantially water-insoluble, and has a room temperature ionic conductivity .gtoreq.10.sup.-4 (ohm-cm).sup.-1, and preferably .gtoreq.0.01 (ohm-cm).sup.-1. The conductivity may be due predominantly to Ag+ ions, as in Ag.sub.2 WO.sub.4.4AgI, or to F- ions, as in Ce.sub.0.95 Ca.sub.0.05 F.sub.2.95. Electrical contacts serve to connect the electrodes to potentiostating and detecting circuitry which controls the potential of the sensing electrode relative to the reference electrode, detects the signal generated by the sensor, and indicates the detected signal.

  11. Humidity-resistant ambient-temperature solid-electrolyte amperometric sensing apparatus and methods

    DOEpatents

    Zaromb, Solomon

    2001-01-01

    Apparatus and methods for detecting selected chemical compounds in air or other gas streams at room or ambient temperature includes a liquid-free humidity-resistant amperometric sensor comprising a sensing electrode and a counter and reference electrode separated by a solid electrolyte. The sensing electrode preferably contains a noble metal, such as Pt black. The electrolyte is water-free, non-hygroscopic, and substantially water-insoluble, and has a room temperature ionic conductivity .gtoreq.10.sup.-4 (ohm-cm).sup.-1, and preferably .gtoreq.0.01 (ohm-cm).sup.-1. The conductivity may be due predominantly to Ag+ ions, as in Ag.sub.2 WO.sub.4.4AgI, or to F- ions, as in Ce.sub.0.95 Ca.sub.0.05 F.sub.2.95. Electrical contacts serve to connect the electrodes to potentiostating and detecting circuitry which controls the potential of the sensing electrode relative to the reference electrode, detects the signal generated by the sensor, and indicates the detected signal.

  12. Formic Acid Dehydrogenation on Au-Based Catalysts at Near-Ambient Temperatures

    SciTech Connect

    Ojeda, Manuel; Iglesia, Enrique

    2008-11-24

    Formic acid (HCOOH) is a convenient hydrogen carrier in fuel cells designed for portable use. Recent studies have shown that HCOOH decomposition is catalyzed with Ru-based complexes in the aqueous phase at near-ambient temperatures. HCOOH decomposition reactions are used frequently to probe the effects of alloying and cluster size and of geometric and electronic factors in catalysis. These studies have concluded that Pt is the most active metal for HCOOH decomposition, at least as large crystallites and extended surfaces. The identity and oxidation state of surface metal atoms influence the relative rates of dehydrogenation (HCOOH {yields} H{sub 2} + CO{sub 2}) and dehydration (HCOOH {yields} H{sub 2}O + CO) routes, a selectivity requirement for the synthesis of CO-free H{sub 2} streams for low-temperature fuel cells. Group Ib and Group VIII noble metals catalyze dehydrogenation selectively, while base metals and metal oxides catalyze both routes, either directly or indirectly via subsequent water-gas shift (WGS) reactions.

  13. Structural transition in sputter-deposited amorphous germanium films by aging at ambient temperature

    NASA Astrophysics Data System (ADS)

    Okugawa, M.; Nakamura, R.; Ishimaru, M.; Watanabe, K.; Yasuda, H.; Numakura, H.

    2016-06-01

    The structure of amorphous Ge (a-Ge) films prepared by sputter-deposition and the effects of aging at ambient temperature and pressure were studied by pair-distribution-function (PDF) analysis from electron scattering and molecular dynamics simulations. The PDFs of the as-deposited and aged samples for 3-13 months showed that the major peaks for Ge-Ge bonds decrease in intensity and broaden with aging for up to 7 months. In the PDFs of a-Ge of molecular dynamics simulation obtained by quenching liquid at different rates, the major peak intensities of a slowly cooled model are higher than those of a rapidly cooled model. Analyses on short- and medium-range configurations show that the slowly cooled model includes a certain amount of medium-range ordered (MRO) clusters, while the rapidly cooled model includes liquid-like configurations rather than MRO clusters. The similarity between experimental and computational PDFs implies that as-deposited films are similar in structure to the slowly cooled model, whereas the fully aged films are similar to the rapidly cooled model. It is assumed that as they undergo room-temperature aging, the MRO clusters disintegrate and transform into liquid-like regions in the same matrix. This transition in local configurations is discussed in terms of instability and the non-equilibrium of nanoclusters produced by a vapor-deposition process.

  14. Systematic effects from an ambient-temperature, continuously rotating half-wave plate

    NASA Astrophysics Data System (ADS)

    Essinger-Hileman, T.; Kusaka, A.; Appel, J. W.; Choi, S. K.; Crowley, K.; Ho, S. P.; Jarosik, N.; Page, L. A.; Parker, L. P.; Raghunathan, S.; Simon, S. M.; Staggs, S. T.; Visnjic, K.

    2016-09-01

    We present an evaluation of systematic effects associated with a continuously rotating, ambient-temperature half-wave plate (HWP) based on two seasons of data from the Atacama B-Mode Search (ABS) experiment located in the Atacama Desert of Chile. The ABS experiment is a microwave telescope sensitive at 145 GHz. Here we present our in-field evaluation of celestial (Cosmic Microwave Background (CMB) plus galactic foreground) temperature-to-polarization leakage. We decompose the leakage into scalar, dipole, and quadrupole leakage terms. We report a scalar leakage of ˜0.01%, consistent with model expectations and an order of magnitude smaller than other CMB experiments have been reported. No significant dipole or quadrupole terms are detected; we constrain each to be <0.07% (95% confidence), limited by statistical uncertainty in our measurement. Dipole and quadrupole leakage at this level lead to systematic error on r ≲ 0.01 before any mitigation due to scan cross-linking or boresight rotation. The measured scalar leakage and the theoretical level of dipole and quadrupole leakage produce systematic error of r < 0.001 for the ABS survey and focal-plane layout before any data correction such as so-called deprojection. This demonstrates that ABS achieves significant beam systematic error mitigation from its HWP and shows the promise of continuously rotating HWPs for future experiments.

  15. Systematic effects from an ambient-temperature, continuously rotating half-wave plate.

    PubMed

    Essinger-Hileman, T; Kusaka, A; Appel, J W; Choi, S K; Crowley, K; Ho, S P; Jarosik, N; Page, L A; Parker, L P; Raghunathan, S; Simon, S M; Staggs, S T; Visnjic, K

    2016-09-01

    We present an evaluation of systematic effects associated with a continuously rotating, ambient-temperature half-wave plate (HWP) based on two seasons of data from the Atacama B-Mode Search (ABS) experiment located in the Atacama Desert of Chile. The ABS experiment is a microwave telescope sensitive at 145 GHz. Here we present our in-field evaluation of celestial (Cosmic Microwave Background (CMB) plus galactic foreground) temperature-to-polarization leakage. We decompose the leakage into scalar, dipole, and quadrupole leakage terms. We report a scalar leakage of ∼0.01%, consistent with model expectations and an order of magnitude smaller than other CMB experiments have been reported. No significant dipole or quadrupole terms are detected; we constrain each to be <0.07% (95% confidence), limited by statistical uncertainty in our measurement. Dipole and quadrupole leakage at this level lead to systematic error on r ≲ 0.01 before any mitigation due to scan cross-linking or boresight rotation. The measured scalar leakage and the theoretical level of dipole and quadrupole leakage produce systematic error of r < 0.001 for the ABS survey and focal-plane layout before any data correction such as so-called deprojection. This demonstrates that ABS achieves significant beam systematic error mitigation from its HWP and shows the promise of continuously rotating HWPs for future experiments.

  16. High Temperature Sorbents for Oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  17. High temperature sorbents for oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1994-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C comprising a porous alumina silicate support, such as zeolite, containing from 1 to 10 percent by weight of ion exchanged transition metal, such as copper or cobalt ions, and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum is described. The activation temperature, oxygen sorption, and reducibility are all improved by the presence of the platinum activator.

  18. Relationship between ambient temperature and heat flux in the scrotal skin.

    PubMed

    Song, G-S; Seo, J T

    2009-08-01

    Excessive scrotal heating or cooling may lead to the cessation of spermatogenesis. Data regarding heat exchange rates in scrotal skin can be used to control testicular temperature within the appropriate range. Heat flux (HF) in the scrotal skin surface is generated based on the surrounding environment. This study aims to elucidate the HF of scrotal skin by varying ambient temperature. Twenty college students including seven varicoceles volunteered as the subjects (mean age: 22.95 +/- SD 1.96 years; height: 175.00 +/- 5.17 cm; weight: 68.40 +/- 8.65 kg; body mass index: 22.28 +/- 2.15), and participated in the experiments from September 11 to October 4, 2006. The environmental temperature was controlled at 20 degrees C and 25 degrees C in the first and second experiment respectively. The HF and skin temperature on both sides of the scrotal surface were measured for 60 min in the environmental chamber. The results revealed that the HF was 87.64 +/- 12.69 W/m(2) and 78.91 +/- 12.09 W/m(2) in the left and right side of the scrotum respectively. The scrotal skin temperature (SST) was 30.28 +/- 0.75 degrees C and 30.24 +/- 0.62 degrees C on the left and right side of the scrotum in the 20 degrees C environment respectively. In the 25 degrees C environment the HF was 53.54 +/- 8.86 W/m(2) and 45.25 +/- 8.32 W/m(2), and the SST was 32.29 +/- 0.61 degrees C and 32.07 +/- 0.36 degrees C on the left and right side of the scrotum respectively. The cooling source power to decrease testicular temperature is suggested at 290 W/m(2). This suggested value could be adopted a cooling device as clinical therapy for a heat stress patient to decrease testicular temperature affecting spermatogenesis.

  19. High Temperature Transfer Molding Resins

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2000-01-01

    High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  20. High-Pressure High-Temperature Phase Diagram of the Organic Crystal Paracetamol

    NASA Astrophysics Data System (ADS)

    Smith, Spencer; Montgomery, Jeffrey; Vohra, Yogesh

    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped diamond as heating anvil. The HPHT data obtained from boron-doped diamond heater is cross-checked with data obtained using a standard block heater diamond anvil cell. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in a number of different experiments. Solid state phase transitions from monoclinic Form I --> orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II --> unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. Our previous angle dispersive x-ray diffraction studies at the Advanced Photon Source has confirmed the existence of two unknown crystal structures Form IV and Form V of paracetamol at high pressure and ambient temperature. The phase transformation from Form II to Form IV occurs at ~8.5 GPa and from Form IV to Form V occurs at ~11 GPa at ambient temperature. Our new data is combined with the previous ambient temperature high-pressure Raman and X- ray diffraction data to create the first HPHT phase diagram of paracetamol. Doe-NNSA Carnegie DOE Alliance Center (CDAC) under Grant Number DE-NA0002006.

  1. Ambient Dried Aerogels

    NASA Technical Reports Server (NTRS)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  2. Effect of sodium bicarbonate supplementation on carcass characteristics of lambs fed concentrate diets at different ambient temperature levels.

    PubMed

    Jallow, Demba B; Hsia, Liang Chou

    2014-08-01

    The objective of this study was to investigate the influence of ambient temperatures on carcass characteristics of lambs fed concentrate diets with or without NaHCO3 supplementation. A slaughter study was carried on 12 male Black Belly Barbados lambs randomly drawn from a growth trial (35 weeks). The lambs were divided into four equal groups and allotted in a 2×2 factorial design. The lambs were allotted at random to two dietary treatments of a basal diet (35:65 roughage:concentrate) or basal diet supplemented with 4% NaHCO3 at different ambient temperatures (20°C and 30°C) in an environment controlled chamber for 10 days. Lambs were slaughtered for carcass evaluation at about 262 days of age (245 days of growth trial, 7 days adaptation and 10 days of experimental period). Ambient temperature had significant (p<0.05, p<0.05, p<0.01, and p<0.001) effects on meat color from the ribeye area (REA), fat, leg and longissimus dorsi muscles with higher values recorded for lambs in the lower temperature group than those from the higher ambient temperature group. Significant differences (p<0.05) in shear force value (kg/cm(2)) recorded on the leg muscles showed higher values (5.32 vs 4.16) in lambs under the lower ambient temperature group compared to the other group. Dietary treatments had significant (p<0.01, p<0.01, and p<0.05) effects on meat color from the REA, fat, and REA fat depth (cm(2)) with higher values recorded for lambs in the NaHCO3 supplementation group than the non supplemented group. Similarly, dietary treatments had significant differences (p<0.05) in shear force value (kg/cm(2)) of the leg muscles with the NaHCO3 groups recording higher (5.30 vs 4.60) values than those from the other group. Neither ambient temperature nor dietary treatments had any significant (p>0.05) effects on pH, and water holding capacity on both muscles. These results indicated that NaHCO3 supplementation at low ambient temperatures had caused an increase in carcass

  3. Analysis of multi-band pyrometry for emissivity and temperature measurements of gray surfaces at ambient temperature

    NASA Astrophysics Data System (ADS)

    Araújo, António

    2016-05-01

    A multi-band pyrometry model is developed to evaluate the potential of measuring temperature and emissivity of assumably gray target surfaces at 300 K. Twelve wavelength bands between 2 and 60 μm are selected to define the spectral characteristics of the pyrometers. The pyrometers are surrounded by an enclosure with known background temperature. Multi-band pyrometry modeling results in an overdetermined system of equations, in which the solution for temperature and emissivity is obtained through an optimization procedure that minimizes the sum of the squared residuals of each system equation. The Monte Carlo technique is applied to estimate the uncertainties of temperature and emissivity, resulting from the propagation of the uncertainties of the pyrometers. Maximum reduction in temperature uncertainty is obtained from dual-band to tri-band systems, a small reduction is obtained from tri-band to quad-band, with a negligible reduction above quad-band systems (a reduction between 6.5% and 12.9% is obtained from dual-band to quad-band systems). However, increasing the number of bands does not always reduce uncertainty, and uncertainty reduction depends on the specific band arrangement, indicating the importance of choosing the most appropriate multi-band spectral arrangement if uncertainty is to be reduced. A reduction in emissivity uncertainty is achieved when the number of spectral bands is increased (a reduction between 6.3% and 12.1% is obtained from dual-band to penta-band systems). Besides, emissivity uncertainty increases for pyrometers with high wavelength spectral arrangements. Temperature and emissivity uncertainties are strongly dependent on the difference between target and background temperatures: uncertainties are low when the background temperature is far from the target temperature, tending to very high values as the background temperature approaches the target temperature.

  4. An artificial neural network approach for the forecast of ambient air temperature

    NASA Astrophysics Data System (ADS)

    Philippopoulos, Kostas; Deligiorgi, Despina; Kouroupetroglou, Georgios

    2014-05-01

    Ambient air temperature forecasting is one of the most significant aspects of environmental and climate research. Accurate temperature forecasts are important in the energy and tourism industry, in agriculture for estimating potential hazards, and within an urban context, in studies for assessing the risk of adverse health effects in the general population. The scope of this study is to propose an Artificial Neural Network (ANN) approach for the one-day ahead maximum (Tmax) and minimum (Tmin) air temperature forecasting. The ANNs are signal processing systems consisted by an assembly of simple interconnected processing elements (neurons) and in geosciences are mainly used in pattern recognition problems. In this study the feed-forward ANN models are selected, which are theoretically capable of estimating a measurable input-output function to any desired degree of accuracy. The method is implemented at a single site (Souda Airport) located at the island of Crete in southeastern Mediterranean and employs the hourly, Tmax and Tmin temperature observations over a ten-yearly period (January 2000 to December 2009). Separate ANN models are trained and tested for the forecast of Tmax and Tmin, which are based on the 24 previous day's hourly temperature records. The first six years are used for training the ANNs, the subsequent two for validating the models and the last two (January 2008 to December 2009) for testing the ANN's overall predicting accuracy. The model architecture consists of a single hidden layer and multiple experiments with varying number of neurons are performed (from 1 to 80 neurons with hyperbolic tangent sigmoid transfer functions). The selection of the optimum number of neurons in the hidden layer is based on a trial and error procedure and the performance is measured using the mean absolute error (MAE) on the validation set. A comprehensive set of model output statistics is used for examining the ability of the models to estimate both Tmax and Tmin

  5. Processing of extraterrestrial materials by high temperature vacuum vaporization

    NASA Technical Reports Server (NTRS)

    Grimley, R. T.; Lipschutz, M. E.

    1983-01-01

    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  6. Staying cool in a changing landscape: the influence of maximum daily ambient temperature on grizzly bear habitat selection.

    PubMed

    Pigeon, Karine E; Cardinal, Etienne; Stenhouse, Gordon B; Côté, Steeve D

    2016-08-01

    To fulfill their needs, animals are constantly making trade-offs among limiting factors. Although there is growing evidence about the impact of ambient temperature on habitat selection in mammals, the role of environmental conditions and thermoregulation on apex predators is poorly understood. Our objective was to investigate the influence of ambient temperature on habitat selection patterns of grizzly bears in the managed landscape of Alberta, Canada. Grizzly bear habitat selection followed a daily and seasonal pattern that was influenced by ambient temperature, with adult males showing stronger responses than females to warm temperatures. Cutblocks aged 0-20 years provided an abundance of forage but were on average 6 °C warmer than mature conifer stands and 21- to 40-year-old cutblocks. When ambient temperatures increased, the relative change (odds ratio) in the probability of selection for 0- to 20-year-old cutblocks decreased during the hottest part of the day and increased during cooler periods, especially for males. Concurrently, the probability of selection for 21- to 40-year-old cutblocks increased on warmer days. Following plant phenology, the odds of selecting 0- to 20-year-old cutblocks also increased from early to late summer while the odds of selecting 21- to 40-year-old cutblocks decreased. Our results demonstrate that ambient temperatures, and therefore thermal requirements, play a significant role in habitat selection patterns and behaviour of grizzly bears. In a changing climate, large mammals may increasingly need to adjust spatial and temporal selection patterns in response to thermal constraints.

  7. High temperature structural sandwich panels

    NASA Astrophysics Data System (ADS)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  8. Preparation and Characterization of Chromium(III)-Activated Yttrium Aluminum Borate: A New Thermographic Phosphor for Optical Sensing and Imaging at Ambient Temperatures.

    PubMed

    Borisov, Sergey M; Gatterer, Karl; Bitschnau, Brigitte; Klimant, Ingo

    2010-05-20

    A new thermographic phosphor based on chromium(III)-doped yttrium aluminum borate (YAB) is obtained as single crystals by high temperature flux growth and as a microcrystalline powder via solution combustion synthesis. The phosphor is excitable both in the blue (lambda(max) 422 nm) and in the red part of the spectrum (lambda(max) 600 nm) and shows bright NIR emission. The brightness of the phosphor is comparable to that of a well-known lamp phosphor Mn(IV)-doped magnesium fluorogermanate. At ambient temperatures, the Cr(III)-doped YAB shows high temperature dependence of the luminescence decay time, which approaches 1% per deg. The material shows no decrease in luminescence intensity at higher temperatures. The new phosphor is particularly promising for applications in temperature-compensated optical chemosensors (including those based on NIR-emitting indicators) and in pressure-sensitive paints.

  9. High Temperature Heat Exchanger Project

    SciTech Connect

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  10. Motor for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  11. Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus)

    PubMed Central

    Haupt, Ryan J.; Avey-Arroyo, Judy A.; Wilson, Rory P.

    2015-01-01

    Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths) had a remarkably low mean food intake of 17 g kg−1day−1 (SD 4.2). Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths. PMID:25861559

  12. Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus).

    PubMed

    Cliffe, Rebecca N; Haupt, Ryan J; Avey-Arroyo, Judy A; Wilson, Rory P

    2015-01-01

    Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths) had a remarkably low mean food intake of 17 g kg(-1)day(-1) (SD 4.2). Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths.

  13. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1992-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  14. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1994-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  15. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1993-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  16. High-temperature geothermal cableheads

    SciTech Connect

    Coquat, J.A.; Eifert, R.W.

    1981-11-01

    Two high-temperature, corrosion-resistant logging cableheads which use metal seals and a stable fluid to achieve proper electrical terminations and cable-sonde interfacings are described. A tensile bar provides a calibrated yield point, and a cone assembly anchors the cable armor to the head. Electrical problems of the sort generally ascribable to the cable-sonde interface were absent during demonstration hostile-environment loggings in which these cableheads were used.

  17. High temperature solar thermal receiver

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A design concept for a high temperature solar thermal receiver to operate at 3 atmospheres pressure and 2500 F outlet was developed. The performance and complexity of windowed matrix, tube-header, and extended surface receivers were evaluated. The windowed matrix receiver proved to offer substantial cost and performance benefits. An efficient and cost effective hardware design was evaluated for a receiver which can be readily interfaced to fuel and chemical processes or to heat engines for power generation.

  18. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    DOEpatents

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  19. HIGH-TEMPERATURE STRAIN GAGE,

    DTIC Science & Technology

    The patent involves a high-temperature tensometer consisting of a strain-sensitive wire grid, a connecting and insulating material, a sub-layer of...heat-resistant material, deposited on the part being investigated or on a backing by gas flame deposition, and a connector to fasten the strain...adhesion, the tension-sensitive wire grid is fastened through the sub-layer to the part being tested by the connecting and insulating material. (Author)

  20. High-Temperature Structural Ceramics

    NASA Astrophysics Data System (ADS)

    Katz, R. Nathan

    1980-05-01

    The unique properties of ceramics based on silicon carbide and silicon nitride make them prime candidates for use in advanced energy conversion systems. These compounds are the bases for broad families of engineering materials, whose properties are reviewed. The relationships between processing, microstructure, and properties are discussed. A review and assessment of recent progress in the use of these materials in high-temperature engineering systems, and vehicular engines in particular, is presented.

  1. High pressure and high temperature apparatus

    DOEpatents

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  2. High temperature catalytic membrane reactors

    SciTech Connect

    Not Available

    1990-03-01

    Current state-of-the-art inorganic oxide membranes offer the potential of being modified to yield catalytic properties. The resulting modules may be configured to simultaneously induce catalytic reactions with product concentration and separation in a single processing step. Processes utilizing such catalytically active membrane reactors have the potential for dramatically increasing yield reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity. Examples of commercial interest include hydrogenation, dehydrogenation, partial and selective oxidation, hydrations, hydrocarbon cracking, olefin metathesis, hydroformylation, and olefin polymerization. A large portion of the most significant reactions fall into the category of high temperature, gas phase chemical and petrochemical processes. Microporous oxide membranes are well suited for these applications. A program is proposed to investigate selected model reactions of commercial interest (i.e. dehydrogenation of ethylbenzene to styrene and dehydrogenation of butane to butadiene) using a high temperature catalytic membrane reactor. Membranes will be developed, reaction dynamics characterized, and production processes developed, culminating in laboratory-scale demonstration of technical and economic feasibility. As a result, the anticipated increased yield per reactor pass economic incentives are envisioned. First, a large decrease in the temperature required to obtain high yield should be possible because of the reduced driving force requirement. Significantly higher conversion per pass implies a reduced recycle ratio, as well as reduced reactor size. Both factors result in reduced capital costs, as well as savings in cost of reactants and energy.

  3. High-temperature sand consolidation

    SciTech Connect

    Friedman, R.H.; Suries, B.W.; Kleke, D.E.

    1987-05-01

    A sand consolidation system has been developed that is stable to wellbore temperatures of 700/sup 0/F (371/sup 0/C). Two improvements in technique have contributed to this development. First, a controlled quantity of catalyst is absorbed on the sand. Consequently, consolidation occurs only on or very near the sand grains, resulting in a high-permeability consolidation. Second, the reaction is driven to completion by avoiding, insofar as possible, the adverse effect of water. The resin used for the consolidation is a very viscous derivative of furfuryl alcohol that requires a diluent to make it injectable. The diulent used to reduce viscosity is a hydrolyzable ester. The diluted fluid, which is sill more viscous than water, displaces much of the water present in the pore space. During the catalyzed consolidation, water produced by the polymerization is removed by reaction with the diluent (hydrolysis of the ester). The high-molecular-weight polymeric consolidation is better able to resist the high temperatures encountered in steam-displacement producing wells. Adaptation of the technology has been made so that the process can also be used in low-temperature wells. Because of the catalysis method, long shelf life is guaranteed for the consolidating formation.

  4. Chemical stability of high-temperature superconductors

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1992-01-01

    A review of the available studies on the chemical stability of the high temperature superconductors (HTS) in various environments was made. The La(1.8)Ba(0.2)CuO4 HTS is unstable in the presence of H2O, CO2, and CO. The YBa2Cu3O(7-x) superconductor is highly susceptible to degradation in different environments, especially water. The La(2-x)Ba(x)CuO4 and Bi-Sr-Ca-Cu-O HTS are relatively less reactive than the YBa2Cu3O(7-x). Processing of YBa2Cu3O(7-x) HTS in purified oxygen, rather than in air, using high purity noncarbon containing starting materials is recommended. Exposure of this HTS to the ambient atmosphere should also be avoided at all stages during processing and storage. Devices and components made out of these oxide superconductors would have to be protected with an impermeable coating of a polymer, glass, or metal to avoid deterioration during use.

  5. High-temperature oxide thermoelectrics

    NASA Astrophysics Data System (ADS)

    Terasaki, Ichiro

    2011-09-01

    We have evaluated the power factor of transition metal oxides at high temperatures using the Heikes formula and the Ioffe-Regel conductivity. The evaluated power factor is found to be nearly independent of carrier concentration in a wide range of doping, and explains the experimental data for cobalt oxides well. This suggests that the same power factor can be obtained with a thermopower larger than 2kB/e, and also suggests a reasonably high value of the dimensionless figure of merit ZT. We propose an oxide thermoelectric power generator by using materials having a thermopower larger than 300 μV/K.

  6. A silver-bearing, High-Temperature, Superconducting (HTS) paint

    NASA Astrophysics Data System (ADS)

    Ferrando, William A.

    1990-02-01

    A substantial set of device applications awaits development of a workable, durable, high-temperature superconducting (HTS) paint. Such a paint should be truly superconducting with its critical temperature T sub c greater than 77K. For most of these applications, a high critical current (J sub c) is not required, although probably desirable. A process is described which can be used to produce silver-bearing HTS paint coatings on many engineering materials. Preliminary tests have shown good adherence to several ceramics and the ability to meet the superconducting criteria. Moreover, the coatings withstand multiple thermal cycling and stability under laboratory ambient storage conditions for periods of at least several months.

  7. High temperature polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1987-01-01

    With the increased emphasis on high performance aircraft the need for lightweight, thermal/oxidatively stable materials is growing. Because of their ease of fabrication, high specific strength, and ability to be tailored chemically to produce a variety of mechanical and physical properties, polymers and polymer matrix composites present themselves as attractive materials for a number of aeropropulsion applications. In the early 1970s researchers at the NASA Lewis Research Center developed a highly processable, thermally stable (600 F) polyimide, PMR-15. Since that time, PMR-15 has become commercially available and has found use in military aircraft, in particular, the F-404 engine for the Navy's F/A-18 strike fighter. The NASA Lewis'contributions to high temperature polymer matrix composite research will be discussed as well as current and future directions.

  8. Containerless processing at high temperatures using acoustic levitation

    NASA Technical Reports Server (NTRS)

    Rey, C. A.; Merkley, D. R.; Hampton, S.; Devos, J.; Mapes-Riordan, D.; Zatarski, M.

    1991-01-01

    Advanced techniques are presented which facilitate the development of inert or reducing atmospheres in excess of 2000 K in order to improve processing of containerless capabilities at higher temperatures and to provide more contamination-free environments. Recent testing, in the laboratory and aboard the NASA KC-135 aircraft, of a high-temperature acoustic positioner demonstrated the effectiveness of a specimen motion damping system and of specimen spin control. It is found that stable positioning can be achieved under ambient and heated conditions, including the transient states of heat-up and cool-down. An incorporated high-temperature levitator was found capable of processing specimens of up to 6-mm diameter in a high-purity environment without the contaminating effects of a container at high temperatures and with relative quiescence.

  9. Interaction between ambient temperature and supplementation of synthetic amino acids on performance and carcass parameters in commercial male turkeys.

    PubMed

    Veldkamp, T; Ferket, P R; Kwakkel, R P; Nixey, C; Noordhuizen, J P

    2000-10-01

    An experiment with male turkeys was conducted to test the hypothesis that turkey production performance responds positively to extra crystalline amino acid supplementation (lysine, methionine, and threonine) when subjected to a high ambient temperature regimen (HT) in the grower period. Two diets were formulated to provide lysine, methionine, and threonine concentrations that either 1) met the breeder recommendations or 2) contained 10% higher lysine and methionine concentrations from 22 to 134 d of age and 10% higher threonine concentration from 22 to 68 d of age. Both diets were fed at two temperatures (15 or 25 C) from 42 d of age onward. At 134 d of age, turkeys on the HT had generally lower BW than those on the low temperature regimen (LT). Up to 68 d of age and from 106 to 134 d of age, feed intake of turkeys on the HT was significantly lower than that of turkeys on the LT. Up to 42 d of age, feed conversion ratio (FCR) of turkeys on the HT were significantly lower than those of turkeys on the LT. Significant treatment interactions were observed from 22 to 41 d of age. Turkeys fed the amino acid-supplemented diets on the LT had significantly reduced FCR, whereas those on the HT did not respond. From 69 to 105 d of age, turkeys on the HT that were fed the supplemented diets had significantly increased FCR, but there were no dietary effects among turkeys on the LT. There were no consistent diet effects on growth performance or carcass yields. Breast meat yields of turkeys on the LT were higher (33.5 vs 32.1%), and drum yields were lower (12.7 vs 13.0%), than those of turkeys on the HT. There were no significant amino acid balance x ambient temperature effects on processing yields. The hypothesis of this experiment could be rejected as production performance did not respond positively to extra supplementation of lysine, methionine, and threonine when subjected to an HT.

  10. Pelage insulation, litter size, and ambient temperature impact maternal energy intake and offspring development during lactation.

    PubMed

    Paul, Matthew J; Tuthill, Christiana; Kauffman, Alexander S; Zucker, Irving

    2010-05-11

    Energy balance during lactation critically influences survival and growth of a mother's offspring, and hence, her reproductive success. Most experiments have investigated the influence of a single factor (e.g., ambient temperature [T(a)] or litter size) on the energetics of lactation. Here, we determined the impact of multiple interventions, including increased conductive heat loss consequent to dorsal fur removal, cold exposure (T(a) of 5 degrees C versus 23 degrees C), and differential lactational load from litters of different sizes (2 or 4 pups), on maternal energy balance and offspring development of Siberian hamsters (Phodopus sungorus). Lower T(a), fur removal, and larger litters were associated with increased maternal food consumption. Females exposed to multiple challenges (e.g., both fur loss and lower T(a)) ate substantially more food than those exposed to a single challenge, with no apparent ceiling to elevated food intake (increases up to 538%). Thus, energy intake of dams under these conditions does not appear to be limited by feeding behavior or the size of the digestive tract. Housing at 5 degrees C attenuated pup weight gain and increased pup mortality to more than 5 times that of litters housed at 23 degrees C. Increases in the dam's conductive heat loss induced by fur removal did not affect pup weight gain or survival, suggesting that effects of low T(a) on pup weight gain and survival reflect limitations in the pups' ability to ingest or incorporate energy.

  11. Influence of alkyl sulfates on waste activated sludge fermentation at ambient temperature.

    PubMed

    Jiang, Su; Chen, Yinguang; Zhou, Qi

    2007-09-05

    Alkyl sulfates (AS), such as sodium dodecyl sulfate (SDS), are widely used in household and industrial products, and can be found in some wastewater and waste activated sludge (WAS). The effect of SDS on the fermentation of WAS at ambient temperature was investigated in this paper. Experimental results showed that the concentrations of protein and carbohydrate in aqueous phase increased with the amount of SDS. The concentrations of both NH(4)(+)-N and PO(4)(3-)-P in fermentation liquor also increased in the presence of SDS. In addition, it was observed that the fermentative short-chain fatty acids (SCFAs) concentration was affected by SDS. With the increase of SDS dosage, the maximum SCFAs concentration increased, and the fermentation time before reaching the maximum SCFAs concentration also increased. Further investigation showed that the produced SCFAs consisted of acetic, propionic, n-butyric, iso-butyric, n-valeric and iso-valeric acids, and acetic, iso-valeric and propionic acids were the three main products. The influence of SDS on methanogenesis was also investigated, and the inhibitory effect of SDS on methanogens activity was observed.

  12. Research on ambient temperature passive magnetic bearings at the Lawrence Livermore National Laboratory

    SciTech Connect

    Post, R.F.; Ryitov, D.D.` Smith, J.R.; Tung, L.S.

    1997-04-01

    Research performed at the Lawrence Livermore National Laboratory on the equilibrium and stability of a new class of ambient-temperature passive bearing systems is described. The basic concepts involved are: (1) Stability of the rotating system is only achieved in the rotating state. That is, disengaging mechanical systems are used to insure stable levitation at rest (when Earnshaw`s theorem applies). (2) Stable levitation by passive magnetic elements can be achieved if the vector sum of the force derivatives of the several elements of the system is net negative (i.e. restoring) for axial, transverse, and tilt-type perturbations from equilibrium. To satisfy the requirements of (2) using only permanent magnet elements we have employed periodic ``Halbach arrays.`` These interact with passive inductive loaded circuits and act as stabilizers, with the primary forces arising from axially symmetric permanent-magnet elements. Stabilizers and other elements needed to create compact passive magnetic bearing systems have been constructed. Novel passive means for stabilizing classes of rotor-dynamic instabilities in such systems have also been investigated.

  13. Ambient temperature as a contributor to kidney stone formation: implications of global warming.

    PubMed

    Fakheri, Robert J; Goldfarb, David S

    2011-06-01

    Nephrolithiasis is a common disease across the world that is becoming more prevalent. Although the underlying cause for most stones is not known, a body of literature suggests a role of heat and climate as significant risk factors for lithogenesis. Recently, estimates from computer models predicted up to a 10% increase in the prevalence rate in the next half century secondary to the effects of global warming, with a coinciding 25% increase in health-care expenditures. Our aim here is to critically review the medical literature relating stones to ambient temperature. We have categorized the body of evidence by methodology, consisting of comparisons between geographic regions, comparisons over time, and comparisons between people in specialized environments. Although most studies are confounded by other factors like sunlight exposure and regional variation in diet that share some contribution, it appears that heat does play a role in pathogenesis in certain populations. Notably, the role of heat is much greater in men than in women. We also hypothesize that the role of a significant human migration (from rural areas to warmer, urban locales beginning in the last century and projected to continue) may have a greater impact than global warming on the observed worldwide increasing prevalence rate of nephrolithiasis. At this time the limited data available cannot substantiate this proposed mechanism but further studies to investigate this effect are warranted.

  14. Pelage insulation, litter size, and ambient temperature impact maternal energy intake and offspring development during lactation

    PubMed Central

    Paul, Matthew J.; Tuthill, Christiana; Kauffman, Alexander S.; Zucker, Irving

    2010-01-01

    Energy balance during lactation critically influences survival and growth of a mother’s offspring, and hence, her reproductive success. Most experiments have investigated the influence of a single factor (e.g., ambient temperature [Ta] or litter size) on the energetics of lactation. Here, we determined the impact of multiple interventions, including increased conductive heat loss consequent to dorsal fur removal, cold exposure (Ta of 5°C versus 23°C), and differential lactational load from litters of different sizes (2 or 4 pups), on maternal energy balance and offspring development of Siberian hamsters (Phodopus sungorus). Lower Ta, fur removal, and larger litters were associated with increased maternal food consumption. Females exposed to multiple challenges (e.g., both fur loss and lower Ta) ate substantially more food than those exposed to a single challenge, with no apparent ceiling to elevated food intake (increases up to 538%). Thus, energy intake of dams under these conditions does not appear to be limited by feeding behavior or the size of the digestive tract. Housing at 5°C attenuated pup weight gain and increased pup mortality to more than 5 times that of litters housed at 23°C. Increases in the dam’s conductive heat loss induced by fur removal did not affect pup weight gain or survival, suggesting that effects of low Ta on pup weight gain and survival reflect limitations in the pups’ ability to ingest or incorporate energy. PMID:20184907

  15. Ambient Temperature Ultrasonic Bonding of Si-Dice Using Sn-3.5wt.%Ag

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Mo; Jung, Jae-Pil; Zhou, Y. Norman; Kim, Jong-Young

    2008-03-01

    Ultrasonic bonding of Si-dice to type FR-4 printed circuit boards (PCB) with Sn-3.5wt.%Ag solder at ambient temperature was investigated. The under-bump metallization (UBM) on the Si-dice comprised Cu/Ni/Al from top to bottom with thicknesses of 0.4 μm, 0.4 μm, and 0.3 μm, respectively. The pads on the PCBs consisted of Au/Ni/Cu with thicknesses of 0.05/5/18 μm, sequentially from top to bottom. Solder was supplied as Sn-3.5wt.%Ag foil rolled to 100 μm thickness, and inserted in the joints. The ultrasonic bonding time was varied from 0.5 s to 3.0 s, and the ultrasonic power was 1400 W. The experimental results showed that reliable joints could be produced between the Si-dice and the PCBs with Sn-3.5wt.%Ag solder. The joint breaking force of “Si-die/solder/FR-4” increased with bonding times up to 2.5 s with a maximum value of 65 N. A bonding time of 3.0 s proved to be excessive, and resulted in cracks along the intermetallic compound between the UBM and solder, which caused a decrease in the bond strength. The intermetallic compound produced by ultrasonic bonding between the UBM and solder was confirmed to be (Cu, Ni)6Sn5.

  16. Activated carbon catalyzed persulfate oxidation of Azo dye acid orange 7 at ambient temperature.

    PubMed

    Yang, Shiying; Yang, Xin; Shao, Xueting; Niu, Rui; Wang, Leilei

    2011-02-15

    Persulfate (PS) oxidative degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e.g., 25°C). It was observed that there existed a remarkable synergistic effect in the GAC/PS combined system. Higher PS concentration and GAC dosage resulted in higher AO7 degrading rates. Near-neutral was the optimal initial pH. Adsorption had an adverse effect on AO7 degradation. AO7 had not only a good decolorization, but a good mineralization. The decomposition of PS followed a first-order kinetics behavior both in the presence and in the absence of AO7. Radical mechanism was studied and three radical scavengers (methanol (MA), tert-butanol (TBA), phenol) were used to determine the kind of major active species taking part in the degradation of AO7 and the location of degradation reaction. It was assumed that the degradation of AO7 did not occur in the liquid phase, but in the porous bulk and boundary layer on the external surface of GAC. SO(4)(-•) or HO•, generated on or near the surface of GAC, played a major role in the AO7 degradation. Finally, the recovery performance of GAC was studied through the GAC reuse experiments.

  17. Equation of State of CAS Phase to Pressure of the Uppermost Lower Mantle at Ambient Temperature

    SciTech Connect

    X Liu; Q He; L Deng; S Zhai; X Hu; B Li; L Zhang; Z Chen; L Qiong

    2011-12-31

    The CAS phase is a major constituent phase for the continental crust and basaltic compositions at the P-T conditions of the Earth's mantle, and potentially plays an important role in the geodynamic processes related to slab subduction. Its equation of state has been investigated here at ambient temperature up to about 25 GPa by using a diamond-anvil cell and synchrotron X-ray radiation. Its P-V data, fitted to the third-order Birch-Murnaghan equation, yield an isothermal bulk modulus (K'{sub T}) of 185 (9) GPa and first pressure derivative (K'{sub T} ) of 7.2 (12). If K'{sub T} is fixed at 4, the derived K{sub T} is 212 (4) GPa. Additionally, the CAS phase is strongly elastically anisotropic, with its a-axis direction much less compressible than c-axis direction: K{sub T-a}:K{sub T-c} = 2.19.

  18. A robust ambient temperature collection and stabilization strategy: Enabling worldwide functional studies of the human microbiome

    PubMed Central

    Anderson, Ericka L.; Li, Weizhong; Klitgord, Niels; Highlander, Sarah K.; Dayrit, Mark; Seguritan, Victor; Yooseph, Shibu; Biggs, William; Venter, J. Craig; Nelson, Karen E.; Jones, Marcus B.

    2016-01-01

    As reports on possible associations between microbes and the host increase in number, more meaningful interpretations of this information require an ability to compare data sets across studies. This is dependent upon standardization of workflows to ensure comparability both within and between studies. Here we propose the standard use of an alternate collection and stabilization method that would facilitate such comparisons. The DNA Genotek OMNIgene∙Gut Stool Microbiome Kit was compared to the currently accepted community standard of freezing to store human stool samples prior to whole genome sequencing (WGS) for microbiome studies. This stabilization and collection device allows for ambient temperature storage, automation, and ease of shipping/transfer of samples. The device permitted the same data reproducibility as with frozen samples, and yielded higher recovery of nucleic acids. Collection and stabilization of stool microbiome samples with the DNA Genotek collection device, combined with our extraction and WGS, provides a robust, reproducible workflow that enables standardized global collection, storage, and analysis of stool for microbiome studies. PMID:27558918

  19. Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M.

    PubMed

    Lutz, Ulrich; Posé, David; Pfeifer, Matthias; Gundlach, Heidrun; Hagmann, Jörg; Wang, Congmao; Weigel, Detlef; Mayer, Klaus F X; Schmid, Markus; Schwechheimer, Claus

    2015-10-01

    Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C) temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae.

  20. Serum leptin, energy budget, and thermogenesis in striped hamsters exposed to consecutive decreases in ambient temperatures.

    PubMed

    Zhao, Zhi-Jun

    2011-01-01

    Leptin has been found to be a direct participant in the regulation of both energy intake and energy expenditure in small mammals showing seasonal declines in body mass (M(b)) and fat mass, but its roles in an animal exhibiting seasonally increased thermogenesis and unchanged M(b) remain unclear. Serum leptin levels, energy budget, and thermogenesis were measured in striped hamsters exposed to consecutive decreases in ambient temperatures ranging from 23° to -23°C. Cold-exposed hamsters had significant increases in gross energy intake (GEI), the rate of basal metabolism, nonshivering thermogenesis, and activity of cytochrome c oxidase (COX) in brown adipose tissue (BAT), compared with control hamsters, indicating a cold-induced elevation of thermogenesis. Body mass and fat content were decreased in cold-exposed animals, and serum leptin levels were increased in hamsters exposed to temperatures of -8°C and below in inverse proportion to body fat content. Serum leptin levels were positively correlated with GEI and BAT COX activity in cold-exposed hamsters, but no such relationships were observed in control animals. These findings suggest that cold-exposed hamsters increase food consumption to meet the energy requirements for increased BAT thermogenesis. The increases in serum leptin levels are likely involved in increased thermogenesis in hamsters under cold stress. Cold-exposed hamsters may become leptin resistant, which is associated with impaired regulation of food intake. This new natural model of leptin resistance may also provide insight into the dynamic long-term control of energy homeostasis for animals that do not exhibit seasonal decline in M(b).