Influence of temperature acclimation and gut content on the supercooling ability of the land snail Cornu aspersum.

PubMed

Ansart, Armelle; Aulne, Pierre-Aymeric; Madec, Luc; Vernon, Philippe

2008-05-01

The invasive land snail Cornu aspersum possesses a low ability to supercool (c. -5 degrees C in winter) and survives only minimal ice formation in its body fluids, what may limit its expansion to colder environments. In the present study, we investigated the influence of acclimation and starvation on its supercooling ability. During eight weeks, individuals were maintained at 20 degrees C, fed or starved, or placed at 5 degrees C, directly or with progressive acclimation to cold and shorter photoperiod. Temperature of crystallisation of whole individual (Tc(I)) and hemolymph (Tc(H)), mass data and gut content were recorded every two weeks. Hemolymphatic glucose and glycerol were measured at the end of experiment and occurrence of intestinal ice-nucleating agents (INA) was researched. Acclimation had no effect on Tc(I) but stimulated purging of the gut. Starvation induced a slight decrease of Tc(I) whereas a high quantity of alimentary particles in the digestive tract limited the supercooling ability. Glucose and glycerol were not synthesized in cold conditions. Mean Tc(H) was low (c. -17 degrees C), some INA being present in hemolymph of fed animals. Intestinal content of starved individuals exhibited a mean Tc of c. -6 degrees C, decreasing to c. -12 degrees after heating, suggesting the presence of organic INA.

Polymorphism, mesomorphism, and metastability of monoelaidin in excess water.

PubMed

Chung, H; Caffrey, M

1995-11-01

The polymorphic and metastable phase behavior of monoelaidin dry and in excess water was studied by using high-sensitivity differential scanning calorimetry and time-resolved x-ray diffraction in the temperature range of 4 degrees C to 60 degrees C. To overcome problems associated with a pronounced thermal history-dependent phase behavior, simultaneous calorimetry and time-resolved x-ray diffraction measurements were performed on individual samples. Monoelaidin/water samples were prepared at room temperature and stored at 4 degrees C for up to 1 week before measurement. The initial heating scan from 4 degrees C to 60 degrees C showed complex phase behavior with the sample in the lamellar crystalline (Lc0) and cubic (Im3m, Q229) phases at low and high temperatures, respectively. The Lc0 phase transforms to the lamellar liquid crystalline (L alpha) phase at 38 degrees C. At 45 degrees C, multiple unresolved lines appeared that coexisted with those from the L alpha phase in the low-angle region of the diffraction pattern that have been assigned previously to the so-called X phase (Caffrey, 1987, 1989). With further heating the X phase converts to the Im3m cubic phase. Regardless of previous thermal history, cooling calorimetric scans revealed a single exotherm at 22 degrees C, which was assigned to an L alpha+cubic (Im3m, Q229)-to-lamellar gel (L beta) phase transition. The response of the sample to a cooling followed by a reheating or isothermal protocol depended on the length of time the sample was incubated at 4 degrees C. A model is proposed that reconciles the complex polymorphic, mesomorphic, and metastability interrelationships observed with this lipid/water system. Dry monoelaidin exists in the lamellar crystalline (beta) phase in the 4 degrees C to 45 degrees C range. The beta phase transforms to a second lamellar crystalline polymorph identified as beta* at 45 degrees C that subsequently melts at 57 degrees C. The beta phase observed with dry monoelaidin is identical to the LcO phase formed by monoelaidin that was dispersed in excess water and that had not been previously heated.

Polymorphism, mesomorphism, and metastability of monoelaidin in excess water.

PubMed Central

Chung, H; Caffrey, M

1995-01-01

The polymorphic and metastable phase behavior of monoelaidin dry and in excess water was studied by using high-sensitivity differential scanning calorimetry and time-resolved x-ray diffraction in the temperature range of 4 degrees C to 60 degrees C. To overcome problems associated with a pronounced thermal history-dependent phase behavior, simultaneous calorimetry and time-resolved x-ray diffraction measurements were performed on individual samples. Monoelaidin/water samples were prepared at room temperature and stored at 4 degrees C for up to 1 week before measurement. The initial heating scan from 4 degrees C to 60 degrees C showed complex phase behavior with the sample in the lamellar crystalline (Lc0) and cubic (Im3m, Q229) phases at low and high temperatures, respectively. The Lc0 phase transforms to the lamellar liquid crystalline (L alpha) phase at 38 degrees C. At 45 degrees C, multiple unresolved lines appeared that coexisted with those from the L alpha phase in the low-angle region of the diffraction pattern that have been assigned previously to the so-called X phase (Caffrey, 1987, 1989). With further heating the X phase converts to the Im3m cubic phase. Regardless of previous thermal history, cooling calorimetric scans revealed a single exotherm at 22 degrees C, which was assigned to an L alpha+cubic (Im3m, Q229)-to-lamellar gel (L beta) phase transition. The response of the sample to a cooling followed by a reheating or isothermal protocol depended on the length of time the sample was incubated at 4 degrees C. A model is proposed that reconciles the complex polymorphic, mesomorphic, and metastability interrelationships observed with this lipid/water system. Dry monoelaidin exists in the lamellar crystalline (beta) phase in the 4 degrees C to 45 degrees C range. The beta phase transforms to a second lamellar crystalline polymorph identified as beta* at 45 degrees C that subsequently melts at 57 degrees C. The beta phase observed with dry monoelaidin is identical to the LcO phase formed by monoelaidin that was dispersed in excess water and that had not been previously heated. Images FIGURE 3 PMID:8580338

Microstructure, mechanical, and in vitro properties of mica glass-ceramics with varying fluorine content.

PubMed

Molla, Atiar Rahaman; Basu, Bikramjit

2009-04-01

The design and development of glass ceramic materials provide us the unique opportunity to study the microstructure development with changes in either base glass composition or heat treatment conditions as well as to understand processing-microstructure-property (mechanical/biological) relationship. In the present work, it is demonstrated how various crystal morphology can develop when F(-) content in base glass (K(2)O-B(2)O(3)-Al(2)O(3)-SiO(2)-MgO-F) is varied in the range of 1.08-3.85% and when all are heat treated at varying temperatures of 1000-1120 degrees C. For some selected heat treatment temperature, the heat treatment time is also varied over 4-24 h. It was established that with increase in fluoride content in the glass composition, the crystal volume fraction of the glass-ceramic decreases. Using 1.08% fluoride, more than 80% crystal volume fraction could be achieved in the K(2)O-B(2)O(3)-Al(2)O(3)-SiO(2)-MgO-F system. It was observed that with lower fluoride content glass-ceramic, if heated at 1040 degrees C for 12 h, an oriented microstructure with 'envelop like' crystals can develop. For glass ceramics with higher fluorine content (2.83% or 3.85%), hexagonal-shaped crystals are formed. Importantly, high hardness of around 8 GPa has been measured in glass ceramics with maximum amount of crystals. The three-point flexural strength and elastic modulus of the glass-ceramic (heat treated at 1040 degrees C for 24 h) was 80 MPa and 69 GPa of the sample containing 3.85% fluorine, whereas, similar properties obtained for the sample containing 1.08% F(-) was 94 MPa and 57 GPa, respectively. Further, in vitro dissolution study of the all three glass-ceramic composition in artificial saliva (AS) revealed that leached fluoride ion concentration was 0.44 ppm, when the samples were immersed in AS for 8 weeks. This was much lower than the WHO recommended safety limits of 1.5 ppm. Among all the investigated glass-ceramic samples, the glass ceramic with 3.85% F(-) content in base glass (heat treated at 1040 degrees C for 12 h), exhibits the adherence of Ca-P layer, which consists of spherical particles of 2-3 mum. Other ions, such as Mg(+2) and K(+1) ion concentrations in the solution were found to be 8 and 315 ppm after 8 weeks of leaching, respectively. The leaching of all metal ions is recorded to decrease with time, probably due to time-dependent kinetic modification of sample surface. Summarizing, the present study illustrates that it is possible to obtain a good combination of crystallization, mechanical and in vitro dissolution properties with the careful selection of base glass composition and heat treatment conditions.

Interventions to prevent hypothermia at birth in preterm and/or low birthweight infants.

PubMed

McCall, Emma M; Alderdice, Fiona; Halliday, Henry L; Jenkins, John G; Vohra, Sunita

2010-03-17

Keeping vulnerable preterm infants warm is problematic even when recommended routine thermal care guidelines are followed in the delivery suite. To assess efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birthweight infants applied within 10 minutes after birth in the delivery suite compared with routine thermal care. We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). The review was updated in October 2009. Trials using randomised or quasi-randomised allocations to test a specific intervention designed to prevent hypothermia, (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery suite to infants of < 37 weeks' gestational age or birthweight

Variations of rat thyroid activity during exposure to high environmental temperature (34 degrees C). Relation between hypothalamic pituitary and thyroid hormone levels.

PubMed

Rousset, B; Cure, M

1975-01-01

Changes in thyroid activity and variations in the hypthalamo-pituitary-thyroid hormone levels were examined in rats exposed to heat (34 degrees C)for3 weeks. Thyroid activity evaluated histologically (epithelium/colloid ratio, nuclear size) by radioiodine exploration (24 hrs 125 I uptake, ratio of mono- to di-125 iodotyrosines - MIT/DIT, ratio of tri- to tetra-125 iodothyronines-T3/T4, and plasma 125I-T4 and assay of plasma T4, evolves in a triphasic manner. 1.a depression phase between day 0 and day 2.5. 2. a rebound of thyroid activity between day 2.5 and day 9.3 a stabilization of thyroid parameters from day 9 to day 24. These results indicate adaptation of thyroid function to heat after 3 weeks. In phase i, plasma TSH )MeKenzie bioassay) fell to undectable levels concurrent with a 50% decrease in hypothalamic TRH (in vitro assay). Plasma TSH peaked on day 4.5, fell on day 9.5 and returned progressively to initial levels. Hypothalamic TRH returned to initial levels after 6.5 days. The rapid and simultaneous decrease in hypothalamic TRH, plasma TSH, plasma T4 and thyroid activity by the 36th hour of heat exposure (34 degrees C) suggests initiation at the hypothalamic level. In the secound phase, the rebound in thyroid activity is presumably due to the peak in circulating TSH in ralation to the marked decrease in plasma T4. The oscillations of phase 2 and the stabilization of all the thyroid parameters in phase 3 may be the reflection of an apparent discrepancy remains between a low plasma T4 and a normal or subnormal plasma TSH. A modification in the "set point" for the control of TSH secretion is discussed.

Global warming transforms coral reef assemblages.

PubMed

Hughes, Terry P; Kerry, James T; Baird, Andrew H; Connolly, Sean R; Dietzel, Andreas; Eakin, C Mark; Heron, Scott F; Hoey, Andrew S; Hoogenboom, Mia O; Liu, Gang; McWilliam, Michael J; Pears, Rachel J; Pratchett, Morgan S; Skirving, William J; Stella, Jessica S; Torda, Gergely

2018-04-01

Global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them 1 . Here we show that in the aftermath of the record-breaking marine heatwave on the Great Barrier Reef in 2016 2 , corals began to die immediately on reefs where the accumulated heat exposure exceeded a critical threshold of degree heating weeks, which was 3-4 °C-weeks. After eight months, an exposure of 6 °C-weeks or more drove an unprecedented, regional-scale shift in the composition of coral assemblages, reflecting markedly divergent responses to heat stress by different taxa. Fast-growing staghorn and tabular corals suffered a catastrophic die-off, transforming the three-dimensionality and ecological functioning of 29% of the 3,863 reefs comprising the world's largest coral reef system. Our study bridges the gap between the theory and practice of assessing the risk of ecosystem collapse, under the emerging framework for the International Union for Conservation of Nature (IUCN) Red List of Ecosystems 3 , by rigorously defining both the initial and collapsed states, identifying the major driver of change, and establishing quantitative collapse thresholds. The increasing prevalence of post-bleaching mass mortality of corals represents a radical shift in the disturbance regimes of tropical reefs, both adding to and far exceeding the influence of recurrent cyclones and other local pulse events, presenting a fundamental challenge to the long-term future of these iconic ecosystems.

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows.

PubMed

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-06-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future.

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows*

PubMed Central

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-01-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future. PMID:26055916

Influence of heat, wind, and humidity on ultraviolet radiation injury.

PubMed

Owens, D W; Knox, J M

1978-12-01

We investigated the influence of heat, wind, and humidity on UVR-induced acute and chronic skin damage of experimental animals housed in environmental chambers and irradiated under controlled conditions. Hairless mice (strain HRS/J) irradiated after an increase of 10 degrees F in skin temperature had more skin damage than irradiated controls. Significantly more Swiss albino mice irradiated for 400 days while maintained at 90 degrees F developed tumors than did those receiving the same amount of UVR but maintained at room temperature. Mice exposed to UVR daily for 4 weeks while kept in wind of 7 mph had greater damage and slower recovery than animals irradiated but protected from wind. Wind also accelerated tumorigenesis in mice than received chronic UVR. Mice kept at 80% relative humidity and given a single dose of UVR had greater skin injury than animals irradiated while at 5% relative humidity. High midity also appears to accelerate skin cancer formation in animals that were exposed to chronic UVR.

Intermittent balneotherapy at the Dead Sea area for patients with knee osteoarthritis.

PubMed

Sherman, Gilad; Zeller, Lior; Avriel, Avital; Friger, Michael; Harari, Marco; Sukenik, Shaul

2009-02-01

Balneotherapy, traditionally administered during a continuous stay at the Dead Sea area, has been shown to be effective for patients suffering from knee osteoarthritis. To evaluate the effectiveness of an intermittent regimen of balneotherapy at the Dead Sea for patients with knee osteoarthritis. Forty-four patients with knee osteoarthritis were included in a prospective randomized single-blind controlled study. The patients were divided into two groups: a treatment group (n=24), which were treated twice weekly for 6 consecutive weeks in a sulfur pool heated to 35-36 degrees C, and a control group (n=20) treated in a Jacuzzi filled with tap water heated to 35-36 degrees C. Participants were assessed by the Lequesne index of osteoarthritis severity, the WOMAC index, the SF-36 quality of health questionnaire, VAS scales for pain (completed by patients and physicians), and physical examination. A statistically significant improvement, lasting up to 6 months, was observed in the treatment group for most of the clinical parameters. In the control group the only improvements were in the SF-36 bodily pain scale at 6 months, the Lequesne index at 1 month and the WOMAC pain score at the end of the treatment period. Although the patients in the control group had milder disease, the difference between the two groups was not statistically significant. Intermittent balneotherapy appears to be effective for patients with knee osteoarthritis.

Effect of prior heat shock on heat resistance of Listeria monocytogenes in meat.

PubMed Central

Farber, J M; Brown, B E

1990-01-01

The effect of prior heat shock on the thermal resistance of Listeria monocytogenes in meat was investigated. A sausage mix inoculated with approximately 10(7) L. monocytogenes per g was initially subjected to a heat shock temperature of 48 degrees C before being heated at a final test temperature of 62 or 64 degrees C. Although cells heat shocked at 48 degrees C for 30 or 60 min did not show a significant increase in thermotolerance as compared with control cells (non-heat shocked), bacteria heat shocked for 120 min did, showing an average 2.4-fold increase in the D64 degrees C value. Heat-shocked cells shifted to 4 degrees C appeared to maintain their thermotolerance for at least 24 h after heat shock. PMID:2116757

Effect of temperature on soluble invertase activity, and glucose, fructose and sucrose status of onion bulbs (Allium cepa) in store.

PubMed

Benkeblia, Noureddine; Onodera, Shuichi; Yoshihira, Taiki; Kosaka, Shinichi; Shiomi, Norio

2004-06-01

The activity of soluble invertase, and the variation in glucose, fructose and sucrose contents in onion bulbs (Allium cepa) during long-term storage at 10 degrees C and 20 degrees C were investigated. Invertase activity increased progressively after 8 weeks to 0.084 and 0.092 nkat/g fresh weight (FW), then sharply to 0.29 and 0.35 nkat/g FW at 20 degrees C and 10 degrees C, respectively, and remained high during 5 weeks. Then, activity decreased abruptly to 0.039 and 0.041 nkat/g, and remained low during the last 8 weeks and close to that observed initially. Glucose increased to 17.73 and 14.62 mg/g FW after 4 weeks at 20 degrees C and 10 degrees C, respectively, then decreased sharply between week 5 and week 7 to 4.13 and 4.91 mg/g FW, respectively, and remained rather stable ranging from 9 and 10 mg/g FW at both temperatures. Fructose showed a similar pattern and was 14.8 and 21.68 mg/g FW at 20 degrees C and 10 degrees C, respectively. Between week 10 and week 24, fructose ranged from 5 and 6 mg/g FW, and from 6 and 7 mg/g FW at 20 degrees C and 10 degrees C, respectively. Sucrose increased to 19.63 and 14.43 mg/g FW at 20 degrees C and 10 degrees C, respectively, decreased during 3 weeks, and then increased randomly from 5.69 to 9.42 mg/g FW at 20 degrees C, but remained in a steady state at 10 degrees C ranging 5.03 +/- 0.78 mg/g FW. During the last 6 weeks, the sucrose content was higher at 20 degrees C than at 10 degrees C. The fructose-glucose ratio varied during the first 8 weeks but remained at a steady level during the last 16 weeks. The (glucose+fructose)/sucrose ratio increased randomly at 10 degrees C, whereas at 20 degrees C the ratio increased during 10 weeks then decreased progressively during the final 14 weeks.

Influence of heat transmission mode on heating rates and on the selection of patches for heating in a mediterranean lizard.

PubMed

Belliure, Josabel; Carrascal, Luis M

2002-01-01

Heliothermy (heat gain by radiation) has been given a prominent role in basking lizards. However, thigmothermy (heat gain by conduction) could be relevant for heating in small lizards. To ascertain the importance of the different heat transmission modes to the thermoregulatory processes, we conducted an experimental study where we analyzed the role of heat transmission modes on heating rates and on the selection of sites for heating in the Mediterranean lizard Acanthodactylus erythrurus (Lacertidae). The study was conducted under laboratory conditions, where two situations of different operative temperatures (38 degrees and 50 degrees C) were simulated in a terrarium. In a first experiment, individuals were allowed to heat up during 2 min at both temperatures and under both heat transmission modes. In a second experiment, individuals were allowed to select between patches differing in the main transmission mode, at both temperatures, to heat up. Experiences were conducted with live, nontethered lizards with a starting body temperature of 27 degrees C. Temperature had a significant effect on the heating rate, with heat gain per unit of time being faster at the higher operative temperature (50 degrees C). The effect of the mode of heat transmission on the heating rate was also significant: at 50 degrees C, heating rate was greater when the main heat transmission mode was conduction from the substrate (thigmothermy) than when heating was mainly due to heat gain by radiation (heliothermy); at 38 degrees C, heating rates did not significantly differ between transmission modes. At 38 degrees C, selection of the site for heating was not significantly different from that expected by chance. However, at 50 degrees C, the heating site offering the slowest heating rate (heliothermic patch) was selected. These results show that heating rates vary not only with environmental temperature but also with different predominant heat transmission modes. Lizards are able to identify and exploit this heterogeneity, selecting the source of heat gain (radiation) that minimizes the risk of overheating when temperature is high.

Skeletal records of community-level bleaching in Porites corals from Palau

NASA Astrophysics Data System (ADS)

Barkley, Hannah C.; Cohen, Anne L.

2016-12-01

Tropical Pacific sea surface temperature is projected to rise an additional 2-3 °C by the end of this century, driving an increase in the frequency and intensity of coral bleaching. With significant global coral reef cover already lost due to bleaching-induced mortality, efforts are underway to identify thermally tolerant coral communities that might survive projected warming. Massive, long-lived corals accrete skeletal bands of anomalously high density in response to episodes of thermal stress. These "stress bands" are potentially valuable proxies for thermal tolerance, but to date their application to questions of community bleaching history has been limited. Ecological surveys recorded bleaching of coral communities across the Palau archipelago during the 1998 and 2010 warm events. Between 2011 and 2015, we extracted skeletal cores from living Porites colonies at 10 sites spanning barrier reef and lagoon environments and quantified the proportion of stress bands present in each population during bleaching years. Across Palau, the prevalence of stress bands tracked the severity of thermal stress, with more stress bands occurring in 1998 (degree heating weeks = 13.57 °C-week) than during the less severe 2010 event (degree heating weeks = 4.86 °C-week). Stress band prevalence also varied by reef type, as more corals on the exposed barrier reef formed stress bands than did corals from sheltered lagoon environments. Comparison of Porites stress band prevalence with bleaching survey data revealed a strong correlation between percent community bleaching and the proportion of colonies with stress bands in each year. Conversely, annual calcification rates did not decline consistently during bleaching years nor did annually resolved calcification histories always track interannual variability in temperature. Our data suggest that stress bands in massive corals contain valuable information about spatial and temporal trends in coral reef bleaching and can aid in conservation efforts to identify temperature-tolerant coral reef communities.

Physiological and pathological characterization of capsaicin-induced reversible nerve degeneration and hyperalgesia.

PubMed

Chiang, H; Chang, K-C; Kan, H-W; Wu, S-W; Tseng, M-T; Hsueh, H-W; Lin, Y-H; Chao, C-C; Hsieh, S-T

2018-07-01

The study aimed to investigate the physiology, psychophysics, pathology and their relationship in reversible nociceptive nerve degeneration, and the physiology of acute hyperalgesia. We enrolled 15 normal subjects to investigate intraepidermal nerve fibre (IENF) density, contact heat-evoked potential (CHEP) and thermal thresholds during the capsaicin-induced skin nerve degeneration-regeneration; and CHEP and thermal thresholds at capsaicin-induced acute hyperalgesia. After 2-week capsaicin treatment, IENF density of skin was markedly reduced with reduced amplitude and prolonged latency of CHEP, and increased warm and heat pain thresholds. The time courses of skin nerve regeneration and reversal of physiology and psychophysics were different: IENF density was still lower at 10 weeks after capsaicin treatment than that at baseline, whereas CHEP amplitude and warm threshold became normalized within 3 weeks after capsaicin treatment. Although CHEP amplitude and IENF density were best correlated in a multiple linear regression model, a one-phase exponential association model showed better fit than a simple linear one, that is in the regeneration phase, the slope of the regression line between CHEP amplitude and IENF density was steeper in the subgroup with lower IENF densities than in the one with higher IENF densities. During capsaicin-induced hyperalgesia, recordable rate of CHEP to 43 °C heat stimulation was higher with enhanced CHEP amplitude and pain perception compared to baseline. There were differential restoration of IENF density, CHEP and thermal thresholds, and changed CHEP-IENF relationships during skin reinnervation. CHEP can be a physiological signature of acute hyperalgesia. These observations suggested the relationship between nociceptive nerve terminals and brain responses to thermal stimuli changed during different degree of skin denervation, and CHEP to low-intensity heat stimulus can reflect the physiology of hyperalgesia. © 2018 European Pain Federation - EFIC®.

How I Manage Athlete's Foot.

PubMed

Hoffmann, Thomas J; Schelkun, Patrice Heinz

1995-04-01

Athlete's foot, or tinea pedis, is a fungal infection that commonly affects active individuals. Intense itching is the primary symptom. Rash distribution, degree of redness, type of scaling, and presence of vesicles can distinguish athlete's foot from inflammatory conditions, but there is much overlap in presentation. Antifungal creams, used consistently for a period of weeks, are generally effective; in certain cases, keratolytics or oral antifungals are necessary. Educating patients about medication use, appropriate footwear, and avoiding excessive heat and moisture can help keep the condition in tow.

Heat-inducible hygromycin resistance in transgenic tobacco.

PubMed

Severin, K; Schöffl, F

1990-12-01

We have constructed a chimaeric gene consisting of the promoter of the soybean heat shock (hs) gene Gmhsp17, 6-L, the coding region of a hygromycin phosphotransferase (hpt) gene, and the termination sequence of the nopaline synthase (nos) gene. This gene fusion was introduced into tobacco by Agrobacterium-mediated gene transfer. Heat-inducible synthesis of mRNA was shown by northern hybridization, and translation of this RNA into a functional protein was indicated by plant growth on hygromycin-containing media in a temperature-dependent fashion. One hour incubation at 40 degrees C per day, applied for several weeks, was sufficient to express the resistant phenotype in transgenic plants containing the chimaeric hs-hpt gene. These data suggest that the hygromycin resistance gene is functional and faithfully controlled by the soybean hs promoter. The suitability of these transgenic plants for selection of mutations that alter the hs response is discussed.

Effects of a pre-moistened multilayered breathable fabric in promoting heat loss during recovery after exercise under hot conditions.

PubMed

Foreman, J H; Benson, G J; Foreman, M H

2006-08-01

Horses generate considerable internal heat burdens when exercising. Although common practice for a trainer or groom to place a wet blanket or towel on the dorsum of a hot horse post exercise, there are no data supporting the efficacy of this cooling method. To test the hypothesis that a pre-moistened blanket designed with a multilayered breathable fabric would enhance heat loss in horses post exercise. Eight treadmill-trained horses performed a standardised exercise test (SET) weekly for 3 weeks, with 3 different recovery treatments administered randomly. Pulmonary artery temperature (PAT) was measured via Swan-Ganz catheter. The SET consisted of 10 min at 3.7 m/sec, 3 min at 11.0 m/sec, 25 min at 3.7 m/sec and 20 min of recovery walking at 2.0 m/sec (58 min exercise and recovery under laboratory conditions of 35.0-40.6 degrees C and 27-49% RH). From 3-7 min during recovery, the treadmill was stopped and horses randomly received either: (a) no bath (negative control); (b) a bath consisting of 32 l of 1-4 degrees C water split into 3-4 cycles of bilateral water application (positive control) followed by water removal ('scraping'); or (c) application of a multilayered fabric blanket soaked in 16-19 degrees C water, wrung out, and placed over the dorsum and sides of the horse. PAT was compared using RM ANOVA with the Student Neuman-Keul's test used post hoc to discriminate between treatments at specific points in time. Mean PAT rose with each phase of exercise (P<0.001) and peaked at a mean of 40.2 +/- 0.2 degrees C. During recovery, the cold bath decreased HR and PAT for 9 min after walking resumed (P<0.001-P<0.05). The blanket did not decrease HR or PAT compared to negative control (P>0.05), and both were hotter than the cold bath treatment through 16 min of recovery (P<0.05). A specially-designed cooling blanket failed to reduce PAT when compared to negative control. Cold water bathing decreased HR and PAT but was not effective throughout all of recovery. A specially-designed, pre-moistened multilayered breathable fabric failed to promote evaporative cooling compared to negative control. Cold water baths may need to be repeated throughout recovery to optimise their effect.

Why wrapping premature neonates to prevent hypothermia can predispose to overheating.

PubMed

Agourram, Bouchra; Bach, Véronique; Tourneux, Pierre; Krim, Gérard; Delanaud, Stéphane; Libert, Jean-Pierre

2010-06-01

Wrapping low-birth-weight neonates in a plastic bag prevents body heat loss. A bonnet can also be used, since large amounts of heat can be lost from the head region, but may provide too much thermal insulation, thus increasing the risk of overheating. We assessed the time required to reach warning body temperature (t38 degrees C), heat stroke (t40 degrees C), or extreme value (t43 degrees C) in a mathematical model that involved calculating various local body heat losses. Simulated heat exchanges were based on body surface temperature distribution measured in preterm neonates exposed to 33 degrees C air temperature (relative air humidity: 35%; air velocity: <0.1 m/s) and covered (torso and limbs) or not with a transparent plastic bag. We also compared metabolic heat production with body heat losses when a bonnet (2 or 3.5 mm thick) covered 10%, 40%, or 100% of the head. Wrapping neonates in a bag (combined or not with a bonnet) does not induce a critical situation as long as metabolic heat production does not increase. When endogenous heat production rises, t38 degrees C ranged between 75 and 287, t40 degrees C between 185 and 549, and t43 degrees C between 287 and 702 min. When this increase was accompanied by a fall in skin temperature, overheating risk was accentuated (37

Conductive heat exchange with a gel-coated circulating water mattress.

PubMed

Bräuer, Anselm; Pacholik, Larissa; Perl, Thorsten; English, Michael John Murray; Weyland, Wolfgang; Braun, Ulrich

2004-12-01

The use of forced-air warming is associated with costs for the disposable blankets. As an alternative method, we studied heat transfer with a reusable gel-coated circulating water mattress placed under the back in eight healthy volunteers. Heat flux was measured with six calibrated heat flux transducers. Additionally, mattress temperature, skin temperature, and core temperature were measured. Water temperature was set to 25 degrees C, 30 degrees C, 35 degrees C, and 41 degrees C. Heat transfer was calculated by multiplying heat flux by contact area. Mattress temperature, skin temperature, and heat flux were used to determine the heat exchange coefficient for conduction. Heat flux and water temperature were related by the following equation: heat flux = 10.3 x water temperature - 374 (r(2) = 0.98). The heat exchange coefficient for conduction was 121 W . m(-2) . degrees C(-1). The maximal heat transfer with the gel-coated circulating water mattress was 18.4 +/- 3.3 W. Because of the small effect on the heat balance of the body, a gel-coated circulating water mattress placed only on the back cannot replace a forced-air warming system.

Heat resistance of Alicyclobacillus acidocaldarius in water, various buffers, and orange juice.

PubMed

Palop, A; Alvarez, I; Raso, J; Condón, S

2000-10-01

The effect of the pH or the composition of the heating medium and of the sporulation temperature on the heat resistance of spores of a thermoacidophilic spore-forming microorganism isolated from a dairy beverage containing orange fruit concentrate was investigated. The species was identified as Alicyclobacillus acidocaldarius. The spores showed the same heat resistance in citrate-phosphate buffers of pH 4 and 7, in distilled water, and in orange juice at any of the temperatures tested (D120 degrees C = 0.1 min and z = 7 degrees C). A raise in 20 degrees C in the sporulation temperature (from 45 to 65 degrees C) increased the heat resistance eightfold (from D110 degrees C = 0.48 min when sporulated at 45 degrees C to 3.9 min when sporulated at 65 degrees C). The z-values remained constant for all sporulation temperatures. The spores of this strain of A. acidocaldarius were very heat resistant and could easily survive any heat treatment currently applied to pasteurize fruit juices.

Metal release from simulated fixed orthodontic appliances.

PubMed

Hwang, C J; Shin, J S; Cha, J Y

2001-10-01

Most orthodontic appliances and archwires are stainless steel or nickel-titanium (NiTi) alloys that can release metal ions, with saliva as the medium. To measure metal released from the fixed orthodontic appliances currently in use, we fabricated simulated fixed orthodontic appliances that corresponded to half of the maxillary arch and soaked them in 50 mL of artificial saliva (pH 6.75 +/- 0.15, 37 degrees C) for 3 months. We used brackets, tubes, and bands made by Tomy (Tokyo, Japan). Four groups were established according to the appliance manufacturer and the type of metal in the .016 x .022-in archwires. Groups A and B were stainless steel archwires from Ormco (Glendora, Calif) and Dentaurum (Ispringen, Germany), respectively, and groups C and D were both NiTi archwires with Ormco's copper NiTi and Tomy's Bioforce sentalloy, respectively. Stainless steel archwires were heat treated in an electric furnace at 500 degrees C for 1 minute and quenched in water. We measured the amount of metal released from each group by immersion time. Our conclusions were as follows: (1) there was no increase in the amount of chromium released after 4 weeks in group A, 2 weeks in group B, 3 weeks in group C, and 8 weeks in group D; (2) there was no increase in the amount of nickel released after 2 weeks in group A, 3 days in group B, 7 days in group C, and 3 weeks in group D; and (3) there was no increase in the amount of iron released after 2 weeks in group A, 3 days in group B, and 1 day in groups C and D. In our 3-month-long investigation, we saw a decrease in metal released as immersion time increased.

[Consequences of short term fluctuations of environmental temperatures in calves--Part 1: Immediate reactions of the respiratory system, the cardiovascular system, metabolism and thermal regulation].

PubMed

Elmer, S; Reinhold, P

2002-04-01

Clinically healthy calves (aged 3-6 weeks) were exposed to defined ambient temperature for 4 hours (cold: 5 degrees C, 60% humidity, n = 12; warm: 35 degrees C, 60% humidity, n = 11). During the exposure of each animal in a climatic chamber, certain parameters of lung function, respiratory mechanics, blood gas analysis, circulation, metabolism and thermal regulation were registered simultaneously in order to study immediate physiological consequences of different environmental conditions. In comparison to control calves (18-20 degrees C, 60% humidity, n = 13) an insufficient adaptation of these young calves was noticed in both cold and warm conditions. At 5 degrees C, marked changes in lung function were observed, i.e. airway constriction, pulmonary hypertension, and ventilation-perfusion-mismatching leading to hypoxemia and hypercapnia. Due to compensation by the circulatory system, a sufficient O2-consumption of the organism as well as an unchanged body temperature were maintained. At 35 degrees C, the respiratory pattern changed to panting and a higher dead space ventilation. No changes were observed in pulmonary gas exchange and blood arterialisation. Due to hyperventilation, the partial pressure for CO2 decreased in blood. Since the body temperature increased continuously, thermal regulation was insufficient. This situation would have led to animals collapsing after a period of heat stress lasting longer than 4 hours. In conclusion, young calves up to the age of 6 weeks were not able to tolerate acute changes in ambient temperature. This was true for cold conditions (5 degrees C) as well as for hot conditions (35 degrees C). The results of this study should be taken into account in order to optimise transport and farming conditions.

Thermal refugia against coral bleaching throughout the northern Red Sea.

PubMed

Osman, Eslam O; Smith, David J; Ziegler, Maren; Kürten, Benjamin; Conrad, Constanze; El-Haddad, Khaled M; Voolstra, Christian R; Suggett, David J

2018-02-01

Tropical reefs have been impacted by thermal anomalies caused by global warming that induced coral bleaching and mortality events globally. However, there have only been very few recordings of bleaching within the Red Sea despite covering a latitudinal range of 15° and consequently it has been considered a region that is less sensitive to thermal anomalies. We therefore examined historical patterns of sea surface temperature (SST) and associated anomalies (1982-2012) and compared warming trends with a unique compilation of corresponding coral bleaching records from throughout the region. These data indicated that the northern Red Sea has not experienced mass bleaching despite intensive Degree Heating Weeks (DHW) of >15°C-weeks. Severe bleaching was restricted to the central and southern Red Sea where DHWs have been more frequent, but far less intense (DHWs <4°C-weeks). A similar pattern was observed during the 2015-2016 El Niño event during which time corals in the northern Red Sea did not bleach despite high thermal stress (i.e. DHWs >8°C-weeks), and bleaching was restricted to the central and southern Red Sea despite the lower thermal stress (DHWs < 8°C-weeks). Heat stress assays carried out in the northern (Hurghada) and central (Thuwal) Red Sea on four key reef-building species confirmed different regional thermal susceptibility, and that central Red Sea corals are more sensitive to thermal anomalies as compared to those from the north. Together, our data demonstrate that corals in the northern Red Sea have a much higher heat tolerance than their prevailing temperature regime would suggest. In contrast, corals from the central Red Sea are close to their thermal limits, which closely match the maximum annual water temperatures. The northern Red Sea harbours reef-building corals that live well below their bleaching thresholds and thus we propose that the region represents a thermal refuge of global importance. © 2017 John Wiley & Sons Ltd.

Experimental and Modelling Study of the Denaturation of Milk Protein by Heat Treatment

PubMed Central

Qian, Fang; Sun, Jiayue; Cao, Di; Tuo, Yanfeng; Jiang, Shujuan; Mu, Guangqing

2017-01-01

Heat treatment of milk aims to inhibit the growth of microbes, extend the shelf-life of products and improve the quality of the products. Heat treatment also leads to denaturation of whey protein and the formation of whey protein-casein polymer, which has negative effects on milk product. Hence the milk heat treatment conditions should be controlled in milk processing. In this study, the denaturation degree of whey protein and the combination degree of whey protein and casein when undergoing heat treatment were also determined by using the Native-PAGE and SDS-PAGE analysis. The results showed that the denaturation degree of whey protein and the combination degree of whey protein with casein extended with the increase of the heat-treated temperature and time. The effects of the heat-treated temperature and heat-treated time on the denaturation degree of whey protein and on the combination degree of whey protein and casein were well described using the quadratic regression equation. The analysis strategy used in this study reveals an intuitive and effective measure of the denaturation degree of whey protein, and the changes of milk protein under different heat treatment conditions efficiently and accurately in the dairy industry. It can be of great significance for dairy product proteins following processing treatments applied for dairy product manufacturing. PMID:28316470

Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae).

PubMed

Johnson, J A; Valero, K A; Wang, S; Tang, J

2004-12-01

While developing radio frequency heat treatments for dried fruits and nuts, we used a heating block system developed by Washington State University to identify the most heat-tolerant life stage of red flour beetle, Tribolium castaneum (Herbst), and to determine its thermal death kinetics. Using a heating rate of 15 degrees C/min to approximate the rapid heating of radio frequency treatments, the relative heat tolerance of red flour beetle stages was found to be older larvae > pupae and adults > eggs and younger larvae. Lethal exposure times for temperatures of 48, 50, and 52 degrees C for the most heat-tolerant larval stage were estimated using a 0.5th order kinetic model. Exposures needed for 95% mortality at 48 degrees C were too long to be practical (67 min), but increasing treatment temperatures to 50 and 52 degrees C resulted in more useful exposure times of 8 and 1.3 min, respectively. Red flour beetle was more sensitive to changes in treatment temperature than previously studied moth species, resulting in red flour beetle being the most heat-tolerant species at 48 degrees C, but navel orangeworm, Amyelois transitella (Walker), being most heat tolerant at 50 and 52 degrees C. Consequently, efficacious treatments for navel orangeworm at 50-52 degrees C also would control red flour beetle.

Comparison of forced-air warming systems with lower body blankets using a copper manikin of the human body.

PubMed

Bräuer, A; English, M J M; Lorenz, N; Steinmetz, N; Perl, T; Braun, U; Weyland, W

2003-01-01

Forced-air warming has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with lower body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of six complete lower body warming systems. Heat transfer of forced-air warmers can be described as follows:[1]Qdot;=h.DeltaT.A where Qdot; = heat transfer [W], h = heat exchange coefficient [W m-2 degrees C-1], DeltaT = temperature gradient between blanket and surface [ degrees C], A = covered area [m2]. We tested the following forced-air warmers in a previously validated copper manikin of the human body: (1) Bair Hugger and lower body blanket (Augustine Medical Inc., Eden Prairie, MN); (2) Thermacare and lower body blanket (Gaymar Industries, Orchard Park, NY); (3) WarmAir and lower body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (4) Warm-Gard(R) and lower body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (5) Warm-Gard and reusable lower body blanket (Luis Gibeck AB); and (6) WarmTouch and lower body blanket (Mallinckrodt Medical Inc., St. Luis, MO). Heat flux and surface temperature were measured with 16 calibrated heat flux transducers. Blanket temperature was measured using 16 thermocouples. DeltaT was varied between -10 and +10 degrees C and h was determined by a linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, because similar mean skin temperatures have been found in volunteers. The area covered by the blankets was estimated to be 0.54 m2. Heat transfer from the blanket to the manikin was different for surface temperatures between 36 degrees C and 38 degrees C. At a surface temperature of 36 degrees C the heat transfer was higher (between 13.4 W to 18.3 W) than at surface temperatures of 38 degrees C (8-11.5 W). The highest heat transfer was delivered by the Thermacare system (8.3-18.3 W), the lowest heat transfer was delivered by the Warm-Gard system with the single use blanket (8-13.4 W). The heat exchange coefficient varied between 12.5 W m-2 degrees C-1 and 30.8 W m-2 degrees C-1, mean DeltaT varied between 1.04 degrees C and 2.48 degrees C for surface temperatures of 36 degrees C and between 0.50 degrees C and 1.63 degrees C for surface temperatures of 38 degrees C. No relevant differences in heat transfer of lower body blankets were found between the different forced-air warming systems tested. Heat transfer was lower than heat transfer by upper body blankets tested in a previous study. However, forced-air warming systems with lower body blankets are still more effective than forced-air warming systems with upper body blankets in the prevention of perioperative hypothermia, because they cover a larger area of the body surface.

[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.

Decreased survival of prostate cancer cells in vitro by combined treatment of heat and an antioxidant inhibitor diethyldithiocarbamate (DDC).

PubMed

Moriyama-Gonda, Nobuko; Igawa, Mikio; Shiina, Hiroaki; Urakami, Shinji; Terashima, Masaharu

2003-11-01

The aim of this study was to examine a modulation of thermotolerance by treatment with combination of heat and the antioxidant inhibitor diethyldithiocarbamate (DDC) of the PC-3 prostate cancer cells. To determine thermotolerance, cells were heated once or twice. Two 1 h exposures at 43 degrees C, with a recovery period in between, revealed better survival/recovery of cells after the second exposure than after the first (fig. 1A + 1B). Additional experiments were performed, heating cells twice (fig. 1B + 1C). First, cells were heated at 43 degrees C for 1 h and, after various recovery times (intervals) at 37 degree C, subsequently reheated at 44 degrees C for 1 h. To ensure effective cell killing, efficiency of the combined treatments of 1 mM DDC and heating at 43 or 44 degrees C for 1 h was estimated by measuring cell survival, reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and heat shock protein 70 (hsp 70) expression. To obtain a more effective method for subsequent heat exposure, cells were heated twice after a 24 h interval in the presence or absence of 1 mM DDC. ROS generation and SOD activity immediately increased correlating with duration of heating, but their levels gently decreased with time after discontinuation of heating. On the other hand, hsp 70 levels slowly increased, also correlating with duration of heating but continued to increase with time after discontinuation of heating for a certain period. DDC administration coupled with heating at 43 or 44 degrees C significantly decreased cell survival compared to heating alone (p < 0.05). Furthermore, significant decreases in numbers of viable cells were observed for cells after the first heat exposure when combined with DDC as compared to heat alone at 43 and 44 degrees C (p < 0.05). These findings suggest that heat combined with DDC could have potential benefits in the treatment of prostate cancer.

Precocious flowering in trees: the FLOWERING LOCUS T gene as a research and breeding tool in Populus.

PubMed

Zhang, Huanling; Harry, David E; Ma, Cathleen; Yuceer, Cetin; Hsu, Chuan-Yu; Vikram, Vikas; Shevchenko, Olga; Etherington, Elizabeth; Strauss, Steven H

2010-06-01

Expression of FLOWERING LOCUS T (FT) and its homologues has been shown to accelerate the onset of flowering in a number of plant species, including poplar (Populus spp.). The application of FT should be of particular use in forest trees, as it could greatly accelerate and enable new kinds of breeding and research. Recent evidence showing the extent to which FT is effective in promoting flowering in trees is discussed, and its effectiveness in poplar is reported. Results using one FT gene from Arabidopsis and two from poplar, all driven by a heat-inducible promoter, transformed into two poplar genotypes are also described. Substantial variation in flowering response was observed depending on the FT gene and genetic background. Heat-induced plants shorter than 30 cm failed to flower as well as taller plants. Plants exposed to daily heat treatments lasting 3 weeks tended to produce fewer abnormal flowers than those in heat treatments of shorter durations; increasing the inductive temperature from 37 degrees C to 40 degrees C produced similar benefits. Using optimal induction conditions, approximately 90% of transgenic plants could be induced to flower. When induced FT rootstocks were grafted with scions that lacked FT, flowering was only observed in rootstocks. The results suggest that a considerable amount of species- or genotype-specific adaptation will be required to develop FT into a reliable means for shortening the generation cycle for breeding in poplar.

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

Russell Feder and Mahmoud Z. Yousef

Neutronics analysis to find nuclear heating rates and personnel dose rates were conducted in support of the integration of diagnostics in to the ITER Upper Port Plugs. Simplified shielding models of the Visible-Infrared diagnostic and of the ECH heating system were incorporated in to the ITER global CAD model. Results for these systems are representative of typical designs with maximum shielding and a small aperture (Vis-IR) and minimal shielding with a large aperture (ECH). The neutronics discrete-ordinates code ATTILA® and SEVERIAN® (the ATTILA parallel processing version) was used. Material properties and the 500 MW D-T volume source were taken frommore » the ITER “Brand Model” MCNP benchmark model. A biased quadrature set equivelant to Sn=32 and a scattering degree of Pn=3 were used along with a 46-neutron and 21-gamma FENDL energy subgrouping. Total nuclear heating (neutron plug gamma heating) in the upper port plugs ranged between 380 and 350 kW for the Vis-IR and ECH cases. The ECH or Large Aperture model exhibited lower total heating but much higher peak volumetric heating on the upper port plug structure. Personnel dose rates are calculated in a three step process involving a neutron-only transport calculation, the generation of activation volume sources at pre-defined time steps and finally gamma transport analyses are run for selected time steps. ANSI-ANS 6.1.1 1977 Flux-to-Dose conversion factors were used. Dose rates were evaluated for 1 full year of 500 MW DT operation which is comprised of 3000 1800-second pulses. After one year the machine is shut down for maintenance and personnel are permitted to access the diagnostic interspace after 2-weeks if dose rates are below 100 μSv/hr. Dose rates in the Visible-IR diagnostic model after one day of shutdown were 130 μSv/hr but fell below the limit to 90 μSv/hr 2-weeks later. The Large Aperture or ECH style shielding model exhibited higher and more persistent dose rates. After 1-day the dose rate was 230 μSv/hr but was still at 120 μSv/hr 4-weeks later. __________________________________________________« less

Responses of bovine lymphocytes to heat shock as modified by breed and antioxidant status.

PubMed

Kamwanja, L A; Chase, C C; Gutierrez, J A; Guerriero, V; Olson, T A; Hammond, A C; Hansen, P J

1994-02-01

We tested whether resistance of lymphocytes to heat stress is modified by breed, intracellular glutathione content, and extracellular antioxidants. In the first experiment, lymphocytes from Angus (Bos taurus, non-heat-tolerant), Brahman (B. indicus, heat-tolerant), and Senepol (B. taurus, heat-tolerant) heifers (12 heifers per breed) were cultured at 45 degrees C for 3 h to evaluate thermal killing, at 42 degrees C for 12 h in a 60-h phytohemagglutinin-induced proliferation test, and at 42 degrees C for 1 h to measure induction of heat shock protein 70 (HSP70). Killing at 45 degrees C was affected by breed x temperature (P < .01); the decrease in viability caused by a temperature of 45 degrees C was greater for Angus than for Brahman or Senepol. For phytohemagglutinin-stimulated lymphocytes, heating to 42 degrees C reduced [3H]thymidine incorporation equally for all breeds. Viability at the end of culture was affected (P < .001) by a breed x temperature interaction because the decrease in viability caused by culture at 42 degrees C was greatest for lymphocytes from Angus heifers. Heat shock for 1 h at 42 degrees C caused a two- to threefold increase in intracellular concentrations of HSP70, but there was no interaction of temperature with breed. In another experiment (with lymphocytes harvested from three Holstein cows), buthionine sulfoximine, a glutathione synthesis inhibitor, inhibited (P < .01) proliferation of phytohemagglutinin-stimulated lymphocytes at 38.5 and 42 degrees C. Addition of the antioxidants glutathione or thioredoxin to culture did not reduce the effects of heating to 42 degrees C on proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Energy balance studies and plasma catecholamine values for patients with healed burns.

PubMed

Wallace, B H; Cone, J B; Caldwell, F T

1991-01-01

We report heat balance studies and plasma catecholamine values for 49 children and young adults with healed burn wounds (age range 0.6 to 31 years and burn range 1% to 82% body surface area burned; mean 41%). All measurements were made during the week of discharge. Heat production for patients with healed burns was not significantly different from predicted normal values. However, compartmented heat loss demonstrated a persistent increment in evaporative heat loss that was secondary to continued elevation of cutaneous water vapor loss immediately after wound closure. A reciprocal decrement in dry heat loss was demonstrated (as a result of a cooler average surface temperature, 0.84 degree C cooler than the average integrated skin temperature of five normal volunteers who were studied in our unit under similar environmental conditions). Mean values for plasma catecholamines were in the normal range: epinephrine = 56 +/- 37 pg/ml, norepinephrine = 385 +/- 220 pg/ml, and dopamine = 34 +/- 29 pg/ml. In conclusion, patients with freshly healed burn wounds have normal rates of heat production; however, there is a residual increment in transcutaneous water vapor loss, which produces surface cooling and decreased average surface temperature, which in turn lowers dry heat loss by an approximately equivalent amount.

Effect of heat treatment on survival of, and growth from, spores of nonproteolytic Clostridium botulinum at refrigeration temperatures.

PubMed Central

Peck, M W; Lund, B M; Fairbairn, D A; Kaspersson, A S; Undeland, P C

1995-01-01

Spores of five type B, five type E, and two type F strains of nonproteolytic Clostridium botulinum were inoculated into tubes of an anaerobic meat medium plus lysozyme to give approximately 10(6) spores per tube. Sets of tubes were then subjected to a heat treatment, cooled, and incubated at 6, 8, 10, 12, and 25 degrees C for up to 60 days. Treatments equivalent to heating at 65 degrees C for 364 min, 70 degrees C for 8 min, and 75 degrees C for 27 min had little effect on growth and toxin formation. After a treatment equivalent to heating at 85 degrees C for 23 min, growth occurred at 6 and 8 degrees C within 28 to 40 days. After a treatment equivalent to heating at 80 degrees C for 19 min, growth occurred in some tubes at 6, 8, 10, or 12 degrees C within 28 to 53 days and at 25 degrees C in all tubes within 15 days. Following a treatment equivalent to heating at 95 degrees C for 15 mine, growth was detected in some tubes incubated at 25 degrees C for fewer than 60 days but not in tubes incubated at 6 to 12 degrees C. The results indicate that heat treatment of processed foods equivalent to maintenance at 85 degrees C for 19 min combined with storage below 12 degrees C and a shelf life of not more than 28 days would reduce the risk of growth from spores of nonproteolytic C. botulinum by a factor of 10(6).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7646016

Heating Oil and Propane Update

EIA Publications

2017-01-01

Weekly residential, wholesale, and spot prices; and production, demand, and stocks of heating fuels. (Weekly heating oil and propane prices are only collected during the heating season which extends from October through March.)

Microwave heating of tea residue yields polysaccharides, polyphenols, and plant biopolyester.

PubMed

Tsubaki, Shuntaro; Iida, Hiroyuki; Sakamoto, Masahiro; Azuma, Jun-ichi

2008-12-10

Microwave heating was used to produce aqueous-soluble components from green, oolong, and black tea residues. Heating at 200-230 degrees C for 2 min extracted 40-50% of polysaccharides and 60-70% of the polyphenols. Solubilization of arabinose and galactose by autohydrolysis occurred with heating above 170 degrees C, whereas heating above 200 degrees C was necessary to solubilize xylose. Catechins were soluble in water by heating at low temperature (110 degrees C); however, new polyphenols having strong antioxidant activity were produced above 200 degrees C. The amount of solubilized materials and antioxidant activity increased with increased fermentation of harvested tea leaves (green tea < oolong tea < black tea). Cutin, a plant biopolyester, remained in the residue after heating as did cellulose and lignin/tannin. The predominant cutin monomer that was recovered was 9,10-epoxy-18-hydroxyoctadecanoic acid, followed by dihydroxyhexadecanoic acid and 9,10,18-trihydroxyoctadecanoic acid.

Growth and survival of uninjured and sublethally heat-injured Escherichia coli O157:H7 on beef extract medium as influenced by package atmosphere and storage temperature.

PubMed

Semanchek, J J; Golden, D A; Williams, R C

1999-03-01

The effect of atmospheric composition and storage temperature on growth and survival of uninjured and sublethally heat-injured Escherichia coli O157:H7, inoculated onto brain heart infusion agar containing 0.3% beef extract (BEM), was determined. BEM plates were packaged in barrier bags in air, 100% CO2, 100% N2, 20% CO2: 80% N2, and vacuum and were stored at 4, 10, and 37 degrees C for up to 20 days. Package atmosphere and inoculum status (i.e., uninjured or heat-injured) influenced (P < 0.01) growth and survival of E. coli O157:H7 stored at all test temperatures. Growth of heat-injured E. coli O157:H7 was slower (P < 0.01) than uninjured E. coli O157:H7 stored at 37 degrees C. At 37 degrees C, uninjured E. coli O157:H7 reached stationary phase growth earlier than heat-injured populations. Uninjured E. coli O157:H7 grew during 10 days of storage at 10 degrees C, while heat-injured populations declined during 20 days of storage at 10 degrees C. Uninjured E. coli O157:H7 stored at 10 degrees C reached stationary phase growth within approximately 10 days in all packaging atmospheres except CO2. Populations of uninjured and heat-injured E. coli O157:H7 declined throughout storage for 20 days at 4 degrees C. Survival of uninjured populations stored at 4 degrees C, as well as heat-injured populations stored at 4 and 10 degrees C, was enhanced in CO2 atmosphere. Survival of heat-injured E. coli O157:H7 at 4 and 10 degrees C was not different (P > 0.05). Uninjured and heat-injured E. coli O157:H7 are able to survive at low temperatures in the modified atmospheres used in this study.

Microwave cyclodestruction for glaucoma in a rabbit model

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

Finger, P.T.; Moshfeghi, D.M.; Smith, P.D.

1991-07-01

Microwave thermotherapy was used to treat experimentally induced glaucoma. Microwave-induced cyclodestruction was successful in reducing intraocular pressure in all treated glaucomatous eyes for 4 weeks. Two additional glaucomatous eyes were left untreated to serve as controls, and were noted to have persistently elevated intraocular pressures. Six additional eyes were then subjected to an equivalent treatment (50 degrees C in five 1-minute applications), which resulted in approximately 180 degrees of heat treatment just posterior to the corneoscleral limbus. These specimens were evaluated with light microscopy at baseline, 24 hours, and 7 days after treatment. The authors clinical and histopathologic evaluations suggestedmore » that microwave thermotherapy (delivered under thermometry control) allowed for chorioretinal/ciliary body destruction that resulted in reductions of intraocular pressure in glaucomatous eyes.« less

The effect of 48 weeks of aerobic exercise training on cutaneous vasodilator function in post-menopausal females.

PubMed

Hodges, Gary J; Sharp, Lisa; Stephenson, Claire; Patwala, Ashish Y; George, Keith P; Goldspink, David F; Tim Cable, N

2010-04-01

Skin blood flow (SkBF) and endothelial-dependent vasodilatation decline with ageing and can be reversed with exercise training. We tested whether 48 weeks of training could improve SkBF and endothelial function in post-menopausal females; 20 post-menopausal subjects completed the study. SkBF was measured by laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated as LDF/blood pressure. Resting CVC was measured at 32 degrees C and peak CVC at 42 degrees C. Cutaneous endothelial-dependent and -independent vasodilatations were determined by the iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. All assessments described were performed at entry (week 0), and after 6, 12, 24, 36, and 48 weeks of training. Resting CVC measures did not change (P > 0.05) throughout the study. Peak CVC increased (P < 0.05) after 24 weeks (7.2 +/- 1.2 vs. 11.6 +/- 1.4 AU mmHg(-1)) and at the 36- and 48-week assessments (13.0 +/- 1.7 and 14.9 +/- 2.1 AU mmHg(-1), respectively). Responses to ACh also increased (P < 0.05) at the 24-week assessment (5.1 +/- 2.1 vs. 8.55 +/- 2.3 AU mmHg(-1)) and increased further at the 36 and 48-week assessments (11.6 +/- 3.7 and 13.2 +/- 3.9 AU mmHg(-1), respectively). Cutaneous responses to SNP increased (P < 0.05) after 36 weeks (8.7 +/- 2.1 vs. 13.02 +/- 2.23 AU mmHg(-1) at 36 weeks). VO(2max) increased after 12 weeks (23.5 +/- 0.7 vs. 25.4 +/- 0.9 ml kg(-1) min(-1)) and improved (P < 0.05) further throughout the study (31.6 +/- 1.8 ml kg(-1) min(-1) at week 48). Aerobic exercise produces positive adaptations in the cutaneous vasodilator function to local heating as well as in cutaneous endothelial and endothelial-independent vasodilator mechanisms. Aerobic capacity was also significantly improved. These adaptations were further enhanced with progressive increases in exercise intensity.

Mass coral bleaching due to unprecedented marine heatwave in Papahānaumokuākea Marine National Monument (Northwestern Hawaiian Islands).

PubMed

Couch, Courtney S; Burns, John H R; Liu, Gang; Steward, Kanoelani; Gutlay, Tiffany Nicole; Kenyon, Jean; Eakin, C Mark; Kosaki, Randall K

2017-01-01

2014 marked the sixth and most widespread mass bleaching event reported in the Northwestern Hawaiian Islands, home to the Papahānaumokuākea Marine National Monument (PMNM), the world's second largest marine reserve. This event was associated with an unusual basin-scale warming in the North Pacific Ocean, with an unprecedented peak intensity of around 20°C-weeks of cumulative heat stress at Lisianksi Island. In situ bleaching surveys and satellite data were used to evaluate the relative importance of potential drivers of bleaching patterns in 2014, assess the subsequent morality and its effects on coral communities and 3D complexity, test for signs of regional acclimation, and investigate long-term change in heat stress in PMNM. Surveys conducted at four island/atoll (French Frigate Shoals, Lisianski Island, Pearl and Hermes Atoll, and Midway Atoll) showed that in 2014, percent bleaching varied considerably between islands/atolls and habitats (back reef/fore reef and depth), and was up to 91% in shallow habitats at Lisianski. The percent bleaching during the 2014 event was best explained by a combination of duration of heat stress measured by Coral Reef Watch's satellite Degree Heating Week, relative community susceptibility (bleaching susceptibility score of each taxon * the taxon's abundance relative to the total number of colonies), depth and region. Mean coral cover at permanent Lisianski monitoring sites decreased by 68% due to severe losses of Montipora dilatata complex, resulting in rapid reductions in habitat complexity. Spatial distribution of the 2014 bleaching was significantly different from the 2002 and 2004 bleaching events likely due to a combination of differences in heat stress and local acclimatization. Historical satellite data demonstrated heat stress in 2014 was unlike any previous event and that the exposure of corals to the bleaching-level heat stress has increased significantly in the northern PMNM since 1982, highlighting the increasing threat of climate change to reefs.

Mass coral bleaching due to unprecedented marine heatwave in Papahānaumokuākea Marine National Monument (Northwestern Hawaiian Islands)

PubMed Central

Couch, Courtney S.; Burns, John H. R.; Liu, Gang; Steward, Kanoelani; Gutlay, Tiffany Nicole; Kenyon, Jean; Eakin, C. Mark; Kosaki, Randall K.

2017-01-01

2014 marked the sixth and most widespread mass bleaching event reported in the Northwestern Hawaiian Islands, home to the Papahānaumokuākea Marine National Monument (PMNM), the world’s second largest marine reserve. This event was associated with an unusual basin-scale warming in the North Pacific Ocean, with an unprecedented peak intensity of around 20°C-weeks of cumulative heat stress at Lisianksi Island. In situ bleaching surveys and satellite data were used to evaluate the relative importance of potential drivers of bleaching patterns in 2014, assess the subsequent morality and its effects on coral communities and 3D complexity, test for signs of regional acclimation, and investigate long-term change in heat stress in PMNM. Surveys conducted at four island/atoll (French Frigate Shoals, Lisianski Island, Pearl and Hermes Atoll, and Midway Atoll) showed that in 2014, percent bleaching varied considerably between islands/atolls and habitats (back reef/fore reef and depth), and was up to 91% in shallow habitats at Lisianski. The percent bleaching during the 2014 event was best explained by a combination of duration of heat stress measured by Coral Reef Watch’s satellite Degree Heating Week, relative community susceptibility (bleaching susceptibility score of each taxon * the taxon’s abundance relative to the total number of colonies), depth and region. Mean coral cover at permanent Lisianski monitoring sites decreased by 68% due to severe losses of Montipora dilatata complex, resulting in rapid reductions in habitat complexity. Spatial distribution of the 2014 bleaching was significantly different from the 2002 and 2004 bleaching events likely due to a combination of differences in heat stress and local acclimatization. Historical satellite data demonstrated heat stress in 2014 was unlike any previous event and that the exposure of corals to the bleaching-level heat stress has increased significantly in the northern PMNM since 1982, highlighting the increasing threat of climate change to reefs. PMID:28953909

[Establishment of heat acclimatization model in rabbits and its pathophysiological characteristics].

PubMed

Wang, Tao; Wang, Jing; Wang, Shang; Li, Pei-Yao; Zhang, Wen-Cheng; Zhao, Xiao-Ling; Wang, Hai

2013-09-01

To establish an effective and stable rabbit heat acclimatization model for the experiment of heat acclimatization mechanisms. Sixteen healthy male rabbits were divided into heat acclimatization group and control group randomly (n = 8). Heat acclimatization (HA) group was kept in simulation chamber with dry bulb temperature of (36 +/- 1) degrees C, wet bulb temperature of (29 +/- 0.5) degrees C, black-bulb temperature of (40 +/- 1.0) degrees C, 100 min/day for 21 days. Control group was kept in the room with temperature of 20 degrees C and relative humidity < 60% during 20 days, then removed into simulation chamber on day 21 to estimate and monitor the rectal temperature together with the heat acclimatization group. Venous blood of control and heat acclimatization group before and after heat exposure on the 1st day, 11th day and 21st day were collected to detect levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and heat shock protein 70 (HSP70) by ELISA analysis. (1) Rectal temperature: There was no significant change in control group during 21 days. In heat acclimatization group, it increased (2.07 +/- 0.43) degrees C after the 1st exposure, and increased (1.78 +/- 0.37) degrees C after the 11th exposure, the range of increasing decreased (0.29 +/- 0.09) degrees C. After the 21st exposure, it increased (1.52 +/- 0.29) degrees C, which was (0.55 +/- 0.14) degrees C lower than that of the 1st (P < 0.05),and (0.53 +/- 0.14) degrees C lower to that of the control group under 1st heat stress (P < 0.05); (2) The level of TNF-alpha after the 1st exposure increased significantly (P < 0.05), but didn't raise along with the exposure times. And fell back to the original level after the 11th and 21st exposure. Compared with control group, the level of IL-6 increased after the 1st, 11th and 21st exposure (P < 0.05), and maintained highly after the 11th and 21st exposure. Compared with the control group, the level of HSP70 increased dramatically with the heat exposure times. Significant increasing of (HSP70) could be detected after the 11th and 21st exposure (P < 0.05), but there was no difference to that of the 1st exposure. Prolonged or repeated exposure to heat stressful environmental conditions can reduce the physiological strain, improve heat tolerance, elicits heat acclimatization.

Winter fuels report, week ending November 12, 1993

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

Not Available

1993-11-18

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: Distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD`s I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD`S; as well as selected National average prices; residential and wholesale pricingmore » data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6--10 Day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city.« less

Increased hospital admissions associated with extreme-heat exposure in King County, Washington, 1990-2010.

PubMed

Isaksen, Tania Busch; Yost, Michael G; Hom, Elizabeth K; Ren, You; Lyons, Hilary; Fenske, Richard A

2015-01-01

Increased morbidity and mortality have been associated with extreme heat events, particularly in temperate climates. Few epidemiologic studies have considered the impact of extreme heat events on hospitalization rates in the Pacific Northwest region. This study quantifies the historic (May to September 1990-2010) heat-morbidity relationship in the most populous Pacific Northwest County, King County, Washington. A relative risk (RR) analysis was used to explore the association between heat and all non-traumatic hospitalizations on 99th percentile heat days, whereas a time series analysis using a piecewise linear model approximation was used to estimate the effect of heat intensity on hospitalizations, adjusted for temporal trends and day of the week. A non-statistically significant 2% [95% CI: 1.02 (0.98, 1.05)] increase in hospitalization risk, on a heat day vs. a non-heat day, was noted for all-ages and all non-traumatic causes. When considering the effect of heat intensity on admissions, we found a statistically significant 1.59% (95% CI: 0.9%, 2.29%) increase in admissions per degree increase in humidex above 37.4°C. Admissions stratified by cause and age produced statistically significant results with both relative risk and time series analyses for nephritis and nephrotic syndromes, acute renal failure, and natural heat exposure hospitalizations. This study demonstrates that heat, expressed as humidex, is associated with increased hospital admissions. When stratified by age and cause of admission, the non-elderly age groups (<85 years) experience significant risk for nephritis and nephrotic syndromes, acute renal failure, natural heat exposure, chronic obstructive pulmonary disease, and asthma hospitalizations.

Three story residence with solar heat--Manchester, New Hampshire

NASA Technical Reports Server (NTRS)

1981-01-01

When heat lost through ducts is counted for accurate performance assessment, solar energy supplied 56 percent of building's space heating load. Average outdoor temperature was 53 degrees F; average indoor temperature was 69 degrees F. System operating modes included heating from solar collectors, storing heat, heating from storage, auxiliary heating with oil fired furnace, summer venting, and hot water preheating.

Relief of Residual Stress in Streamline Tie Rods by Heat Treatment

NASA Technical Reports Server (NTRS)

Pollard, R E; Reinhart, Fred M

1941-01-01

About two-thirds of the residual stress in cold-worked SAE 1050 steel tie rods was relieved by heating 30 minutes at 600 degrees Fahrenheit. Cold-worked austenitic stainless-steel tie rods could be heated at temperatures up to 1000 degrees Fahrenheit without lowering the important physical properties. The corrosion resistance, in laboratory corrosion test, of straight 18:8 and titanium-treated 18:8 materials appeared to be impaired after heating at temperatures above 800 degrees or 900 degrees fahrenheit. Columbium-treated and molybdenum-treated 18:8 steel exhibited improved stability over a wide range of temperatures. Tie rods of either material could be heated 30 minutes with safety at any temperature up to 1000 degrees Fahrenheit. At this temperature most of the residual stress would be relieved.

Human milk antibacterial factors: the effect of temperature on defense systems.

PubMed

Chen, H Y; Allen, J C

2001-01-01

Bovine milk will eventually spoil at refrigeration temperatures, but endogenous or exogenous pathogenic or spoilage bacteria in human milk stored for delayed feeding will die. We investigated the mechanism for these antibacterial properties and their response to high-tempertature, short-time (HTST, 72 degrees C-75 degrees C, 15 sec) and low-temperature long-time (LTLT, 65 degrees C, 30 min) pasteurization. Nonpathogenic Listeria innocua (10(6) cfu/mL) was inoculated into raw and processed bovine and human milk; bacterial plate counts twice weekly determined antibacterial activities. Up to 99% of L. innocua were killed and further growth was inhibited in raw and pasteurized human milk for at least 60 days at 4 degrees C. Reactive IgA antibodies against Listeria antigens were demonstrated by enzyme immunoassay in some human milk samples; sIgA activity against Escherichia coli O antigens was significantly decreased by heat treatments (raw, 1.8; HTST, 1.1; LTLT, 1.3 activity units). Adding human lactoferrin (0.5-20 mg/mL) to the Listeria inoculum (approximately 10(7) cfu/mL) in 1% peptone water did not inhibit bacterial growth.

Beyond peak summer temperatures, branching corals in the Gulf of Aqaba are resilient to thermal stress but sensitive to high light

NASA Astrophysics Data System (ADS)

Bellworthy, Jessica; Fine, Maoz

2017-12-01

Despite rapidly rising sea surface temperatures and recurrent positive temperature anomalies, corals in the Gulf of Aqaba (GoA) rarely experience thermal bleaching. Elsewhere, mass coral bleaching has been observed in corals when the water temperature exceeds 1-2 °C above the local maximum monthly mean (MMM). This threshold value or "bleaching rule" has been used to create predictive models of bleaching from satellite sea surface temperature observations, namely the "degree heating week" index. This study aimed to characterize the physiological changes of dominant reef building corals from the GoA in response to a temperature and light stress gradient. Coral collection and experiments began after a period of 14 consecutive days above MMM in the field. Stylophora pistillata showed negligible changes in symbiont and host physiology parameters after accumulating up to 9.4 degree heating weeks during peak summer temperatures, for which the index predicts widespread bleaching and some mortality. This result demonstrates acute thermal tolerance in S. pistillata from the GoA and deviation from the bleaching rule. In a second experiment after 4 weeks at 4 °C above peak summer temperatures, S. pistillata and Acropora eurystoma in the high-light treatment visibly paled and suffered greater midday and afternoon photoinhibition compared to corals under low-light conditions (35% of high-light treatment). However, light, not temperature (alone or in synergy with light), was the dominant factor in causing paling and the effective quantum yield of corals at 4 °C above ambient was indistinguishable from those in the ambient control. This result highlights the exceptional, atypical thermal tolerance of dominant GoA branching corals. Concomitantly, it validates the efficacy of protecting GoA reefs from local stressors if they are to serve as a coral refuge in the face of global sea temperature rise.

Effects of several factors on the heat-shock-induced thermotolerance of Listeria monocytogenes.

PubMed Central

Pagán, R; Condón, S; Sala, F J

1997-01-01

The influence of the temperature at which Listeria monocytogenes had been grown (4 or 37 degrees C) on the response to heat shocks of different durations at different temperatures was investigated. For cells grown at 4 degrees C, the effect of storage, prior to and after heat shock, on the induced thermotolerance was also studied. Death kinetics of heat-shocked cells is also discussed. For L. monocytogenes grown at 37 degrees C, the greatest response to heat shock was a fourfold increase in thermotolerance. For L. monocytogenes grown at 4 degrees C, the greatest response to heat shock was a sevenfold increase in thermotolerance. The only survival curves of cells to have shoulders were those for cells that had been heat shocked. A 3% concentration of sodium chloride added to the recovery medium made these shoulders disappear and decreased decimal reduction times. The percentage of cells for which thermotolerance increased after a heat shock was smaller the milder the heat shock and the longer the prior storage. PMID:9251209

Whole-body heating decreases skin vascular response to low orthostatic stress in the lower extremities.

PubMed

Yamazaki, Fumio; Nakayama, Yoshiro; Sone, Ryoko

2006-04-01

To elucidate the influence of heat stress on cutaneous vascular response in the lower extremities during orthostatic stress, a head-up tilt (HUT) test at angles of 15 degrees, 30 degrees, 45 degrees, and 60 degrees for 4 min each was conducted under normothermic control conditions followed by whole-body heat stress produced by a hot water-perfused suit in healthy volunteers. Skin blood flows (SkBF) in the forearm, thigh, and calf were monitored using laser-Doppler flowmetry throughout the experiment. Furthermore, to elucidate the effects of increased core and local skin temperatures on the local vascular response in calf skin under increasing orthostatic stress, the thigh was occluded at 20, 30, 50, 70, and 80 mmHg with a cuff in both the normothermic condition and the whole-body or local heating condition. Significant decreases in forearm SkBF during HUT were observed at an angle of 60 degrees during normothermia and at 30 degrees or more during heating. SkBF in the thigh and calf was decreased significantly by HUT at 15 degrees and above during normothermia, and there was no significant reduction of SkBF in these sites during HUT at the lower angles (15 degrees -45 degrees ) during whole-body heating. Significant decreases of calf SkBF were observed at cuff pressures of 20 mmHg and above during normothermia and of 30 mmHg and above during whole-body and local heating, respectively. These results suggest that SkBF in the lower extremities shows a marked reduction compared with the upper extremities during low orthostatic stress in normothermia, and the enhanced skin vasoconstrictor response in the lower extremities is diminished by both whole-body and local heat stress.

Heat shock and thermotolerance of Escherichia coli O157:H7 in a model beef gravy system and ground beef.

PubMed

Juneja, V K; Klein, P G; Marmer, B S

1998-04-01

Duplicate beef gravy or ground beef samples inoculated with a suspension of a four-strain cocktail of Escherichia coli O157:H7 were subjected to sublethal heating at 46 degrees C for 15-30 min, and then heated to a final internal temperature of 60 degrees C. Survivor curves were fitted using a linear model that incorporated a lag period (TL), and D-values and 'time to a 4D inactivation' (T4D) were calculated. Heat-shocking allowed the organism to survive longer than non-heat-shocked cells; the T4D values at 60 degrees C increased 1.56- and 1.50-fold in beef gravy and ground beef, respectively. In ground beef stored at 4 degrees C, thermotolerance was lost after storage for 14 h. However, heat-shocked cells appeared to maintain their thermotolerance for at least 24 h in ground beef held to 15 or 28 degrees C. A 25 min heat shock at 46 degrees C in beef gravy resulted in an increase in the levels of two proteins with apparent molecular masses of 60 and 69 kDa. These two proteins were shown to be immunologically related to GroEL and DnaK, respectively. Increased heat resistance due to heat shock must be considered while designing thermal processes to assure the microbiological safety of thermally processed foods.

Evaluation of different shades to improve dairy cattle well-being in Argentina.

PubMed

Valtorta, S E; Leva, P E; Gallardo, M R

1997-11-01

Two tree shades (TS1 and TS2) and an artificial shade structure (AS) were evaluated using black globe temperatures (BGTs) to assess their effectiveness in reducing heat load. The artificial structure consisted of a black woven polypropylene cloth providing 80% shade, mounted on 2.5-m-high eucalyptus posts. The work was carried out at Rafaela Experimental Station, Argentina, during the summer (January and February) 1994. BGTs and floor temperatures were measured in concrete floor holding pens with and without artificial shade. The results showed no difference between TS1, TS2 and AS, their average BGTs being 30.2 (SD 0.58), 29.0 (SD 0.70) and 30.2 (SD 0.74) degrees C, respectively. BGTs under all three shades were significantly lower (P < 0.01) than the average BGT recorded outside: 35.5 (SD 1.12) degrees C. Average BGTs in holding pens were 32.4 (SD 1.38) and 39.9 (SD 1.91) degrees C for shaded and non-shaded areas (P < 0.01). The corresponding average floor temperatures were 27.8 (SD 0.68) degrees C and 47.7 (SD 2.13) degrees C (P < 0.01). To assess the effects of shade on animal well-being, afternoon rectal temperatures (RT) and respiratory rate (respirations per minute, RR) of lactating cows were recorded twice a week. Rectal temperatures were significantly higher for non-shaded cows (P < 0.01), mean RT being 40.1 (SD 0.65) degrees C vs 39.3 (SD 0.42) degrees C for the shaded animals. Corresponding RRs were 78.9 (SD 18.0) and 60.7 (SD 10.6) (P < 0.05). It was concluded that: (1) tree and artificial shades produced similar effects, (2) shading the holding pen with an 80% shading cloth was effective in reducing heat load and floor temperatures, and (3) access to shade in our pasture-based system improved animal well-being.

Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality.

PubMed

O'Neill, Marie S; Hajat, Shakoor; Zanobetti, Antonella; Ramirez-Aguilar, Matiana; Schwartz, Joel

2005-11-01

We assessed the influence of control for air pollution and respiratory epidemics on associations between apparent temperature (AT) and daily mortality in Mexico City and Monterrey. Poisson regressions were fit to mortality among all ages, children (ages 0-14 years) and the elderly (ages >or=65 years). Predictors included mean daily AT, season, day of week and public holidays for the base model. Respiratory epidemics and air pollution (particulate matter <10 microm in aerodynamic diameter and O3) were added singly and then jointly for a fully adjusted model. Percent changes in mortality were calculated for days of relatively extreme temperatures [cold (10-11 degrees C) for both cities and heat (35-36 degrees C) for Monterrey], compared to days at the overall mean temperature in each city (15 degrees C in Mexico City, 25 degrees C in Monterrey). In Mexico City, total mortality increased 12.4% [95% confidence interval (CI) 10.5%, 14.5%] on cold days (fully adjusted). Among children, the adjusted association was similar [10.9% (95% CI: 5.4%, 16.7%)], but without control for pollution and epidemics, was nearly twice as large [19.7% (95% CI: 13.9%, 25.9)]. In Monterrey, the fully adjusted heat effect for all deaths was 18.7% (95% CI: 11.7%, 26.1%), a third lower than the unadjusted estimate; the heat effect was lower among children [5.5% (95% CI: -10.1%, 23.8%)]. Cold had a similar effect on all-age mortality as in Mexico City [11.7% (95% CI: 3.7%, 20.3%)]. Responses of the elderly differed little from all-ages responses in both cities. Associations between weather and health persisted even with control for air pollution and respiratory epidemics in two Mexican cities, but risk assessments and climate change adaptation programs are best informed by analyses that account for these potential confounders.

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

Russell E. Feder and Mahmoud Z. Youssef

Neutronics analysis to find nuclear heating rates and personnel dose rates were conducted in support of the integration of diagnostics in to the ITER Upper Port Plugs. Simplified shielding models of the Visible-Infrared diagnostic and of a large aperture diagnostic were incorporated in to the ITER global CAD model. Results for these systems are representative of typical designs with maximum shielding and a small aperture (Vis-IR) and minimal shielding with a large aperture. The neutronics discrete-ordinates code ATTILA® and SEVERIAN® (the ATTILA parallel processing version) was used. Material properties and the 500 MW D-T volume source were taken from themore » ITER “Brand Model” MCNP benchmark model. A biased quadrature set equivelant to Sn=32 and a scattering degree of Pn=3 were used along with a 46-neutron and 21-gamma FENDL energy subgrouping. Total nuclear heating (neutron plug gamma heating) in the upper port plugs ranged between 380 and 350 kW for the Vis-IR and Large Aperture cases. The Large Aperture model exhibited lower total heating but much higher peak volumetric heating on the upper port plug structure. Personnel dose rates are calculated in a three step process involving a neutron-only transport calculation, the generation of activation volume sources at pre-defined time steps and finally gamma transport analyses are run for selected time steps. ANSI-ANS 6.1.1 1977 Flux-to-Dose conversion factors were used. Dose rates were evaluated for 1 full year of 500 MW DT operation which is comprised of 3000 1800-second pulses. After one year the machine is shut down for maintenance and personnel are permitted to access the diagnostic interspace after 2-weeks if dose rates are below 100 μSv/hr. Dose rates in the Visible-IR diagnostic model after one day of shutdown were 130 μSv/hr but fell below the limit to 90 μSv/hr 2-weeks later. The Large Aperture style shielding model exhibited higher and more persistent dose rates. After 1-day the dose rate was 230 μSv/hr but was still at 120 μSv/hr 4-weeks later.« less

Inactivation of Geobacillus stearothermophilus spores by high-pressure carbon dioxide treatment.

PubMed

Watanabe, Taisuke; Furukawa, Soichi; Hirata, Junichi; Koyama, Tetsuya; Ogihara, Hirokazu; Yamasaki, Makari

2003-12-01

High-pressure CO2 treatment has been studied as a promising method for inactivating bacterial spores. In the present study, we compared this method with other sterilization techniques, including heat and pressure treatment. Spores of Bacillus coagulans, Bacillus subtilis, Bacillus cereus, Bacillus licheniformis, and Geobacillus stearothermophilus were subjected to CO2 treatment at 30 MPa and 35 degrees C, to high-hydrostatic-pressure treatment at 200 MPa and 65 degrees C, or to heat treatment at 0.1 MPa and 85 degrees C. All of the bacterial spores except the G. stearothermophilus spores were easily inactivated by the heat treatment. The highly heat- and pressure-resistant spores of G. stearothermophilus were not the most resistant to CO2 treatment. We also investigated the influence of temperature on CO2 inactivation of G. stearothermophilus. Treatment with CO2 and 30 MPa of pressure at 95 degrees C for 120 min resulted in 5-log-order spore inactivation, whereas heat treatment at 95 degrees C for 120 min and high-hydrostatic-pressure treatment at 30 MPa and 95 degrees C for 120 min had little effect. The activation energy required for CO2 treatment of G. stearothermophilus spores was lower than the activation energy for heat or pressure treatment. Although heat was not necessary for inactivationby CO2 treatment of G. stearothermophilus spores, CO2 treatment at 95 degrees C was more effective than treatment at 95 degrees C alone.

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

PubMed

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

2000-01-01

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

Post-cure heat treatments for composites: properties and fractography.

PubMed

Ferracane, J L; Condon, J R

1992-09-01

Two commercial and four experimental composites were subjected to post-cure heat treatments of 10 min and 3 h duration immediately after light-curing. Fracture toughness, flexural modulus, microhardness and degree of conversion (FTIR) were evaluated 24 h later. The results showed that post-cure heat treatments at 120 degrees C of short or long duration can be used to produce significant improvements in the degree of cure and the mechanical properties of dental composites used as inlays. A 10 min heat treatment was as effective as a 3 h treatment in enhancing properties and degree of cure. In addition, a 3 h heat treatment carried out 7 days after the initial light-curing was capable of improving properties and cure to almost the same extent as the immediate heat treatments. The improvement in properties, in conjunction with the fractography, indicate a toughening of the filled resin matrix and possibly an improved filler/matrix adhesion in the microfills. The changes appear to be predominantly the result of an increase in degree of cure.

Individual thermal profiles as a basis for comfort improvement in space and other environments

NASA Technical Reports Server (NTRS)

Koscheyev, V. S.; Coca, A.; Leon, G. R.; Dancisak, M. J.

2002-01-01

BACKGROUND: The development of individualized countermeasures to address problems in thermoregulation is of considerable importance for humans in space and other extreme environments. A methodology is presented for evaluating minimal/maximal heat flux from the total human body and specific body zones, and for assessing individual differences in the efficiency of heat exchange from these body areas. The goal is to apply this information to the design of individualized protective equipment. METHODS: A multi-compartment conductive plastic tubing liquid cooling/warming garment (LCWG) was developed. Inlet water temperatures of 8-45 degrees C were imposed sequentially to specific body areas while the remainder of the garment was maintained at 33 degrees C. RESULTS: There were significant differences in heat exchange level among body zones in both the 8 degrees and 45 degrees C temperature conditions (p < 0.001). The greatest amount of heat was absorbed/released by the following areas: thighs (8 degrees C: -2.12 +/- 0.14 kcal min(-1); 45 degrees C: +1.58 +/- 0.23); torso (8 degrees C: -2.12 +/- 0.13 kcal min(-1); 45 degrees C: +1.31 +/- 0.27); calves (8 degrees C: -1.59 +/- 0.26 kcal min(-1); 45 degrees C: +1.53 +/- 0.24); and forearms (8 degrees C: -1.67 +/- 0.29 kcal x min(-1); 45 degrees C: +1.45 +/- 0.20). These are primarily zones with relatively large muscle mass and adipose tissue. Calculation of absorption/release heat rates standardized per unit tube length and flow rate instead of zonal surface area covered showed that there was significantly greater heat transfer in the head, hands, and feet (p < 0.001). The areas in which there was considerable between-subject variability in rates of heat transfer and thus most informative for individual profile design were the torso, thighs, shoulders, and calves or forearms. CONCLUSIONS: The methodology developed is sensitive to individual differences in the process of heat exchange and variations in different body areas, depending on their size and tissue mass content. The design of individual thermal profiles is feasible for better comfort of astronauts on long-duration missions and personnel in other extreme environments.

Gunion - Nevada`s most innovative geothermal food dehydration facility

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

Trexler, D.T.; Taylan, G.; Stewart, M.B.

1995-12-31

The Gunion (garlic and onion) dehydration plant, owned and operated by Integrated Ingredients, a Division of Burns Philp Food, Incorporated, uses geothermal fluids at a temperature of 306{degrees}F to dehydrate 50 to 70-thousand pounds per day of garlic and onions. The geothermal fluids are provided by Empire Farms, who has the rights for development of the resource and is the lease holder of fee land known as the Kosmos Lease. The San Emidio KGRA is located in northern Washoe County, 90 miles north-northeast of Reno, Nevada and 20 miles south of Gerlach, Nevada. Geothermal fluids exit the plant at 242{degrees}Fmore » and are piped to an injection well located 3,000 feet south-southwest of the plant. The plant location was selected not only for the geothermal resource, but also for the area`s low relative humidity. Currently, 1100-1200 gpm of geothermal fluids, at an inlet temperature of 302{degrees}F, are sufficient to provide the dryer line with ample BTU`s. Three geothermal wells drilled to depths ranging from 493 to 1817 feet produce fluids ranging in temperature from 266 to 306{degrees}F. One well can easily provide the heat required by the dryer line and will be capable of providing heat for a planned three-fold expansion of the facility. The remaining two wells are used as backup, or may be used for other applications such as soil sterilization. The fluid exiting the plant at 242{degrees}F may be cascaded and used for greenhouses and soil warming in the future. Geothermal heat is also used to dehumidify onions placed in the cold storage facility. The dehydration process takes 5-6 hours to dry the product to a 4.5% moisture content. The dried product is then milled to various sizes from powder to granules. The dehydration plant operates 24 hours/day 7 days a week. Currently 80 people are employed full-time at the plant. The dehydrated onion and garlic are used in condiments, soups, sauces and salad dressing.« less

A Ceramic Heat Exchanger for Solar Receivers

NASA Technical Reports Server (NTRS)

Robertson Jr., C.; Stacy, L.

1985-01-01

Design intended for high-temperature service. Proposed ceramic-tube and header heat exchangers used for solar-concentrating collector operating in 25- to 150-KW power range at temperatures between 2,000 degrees and 3,000 degrees F (1,095 degrees and 1,650 degrees C).

Dry-heat resistance of selected psychrophiles.

PubMed Central

Winans, L; Pflug, I J; Foster, T L

1977-01-01

The dry-heat resistance characteristics of spores of psychrophilic organisms isolated from soil samples from the Viking spacecraft assembly areas at Cape Kennedy Space Flight Center, Cape Canaveral, Fla., were studied. Spore suspensions were produced, and dry-heat D values were determined for the microorganisms that demonstrated growth or survival under a simulated Martian environment. The dry-heat tests were carried out by using the planchet-boat-hot plate system at 110 and 125 degrees C with an ambient relative humidity of 50% at 22 degrees C. The spores evaluated had a relatively low resistance to dry heat. D(110 degrees C) values ranged from 7.5 to 122 min, whereas the D(123 degrees C) values ranged from less than 1.0 to 9.8 min. PMID:410367

Developmental competence of bovine embryos from heat-stressed ova.

PubMed

Edwards, J L; Bogart, A N; Rispoli, L A; Saxton, A M; Schrick, F N

2009-02-01

Because multiple ovulation embryo transfer procedures are occasionally performed in cows experiencing heat stress, the goal of this study was to assess the developmental competence of otherwise morphologically normal embryos from heat-stressed ova. To this end, the ability of compact morulae from heat-stressed and non-heat-stressed bovine ova to undergo blastocyst development after culture at 38.5 or 41.0 degrees C was examined. It was hypothesized that heat-induced perturbations in the ooplasm carry over to increase the susceptibility of the preattachment embryo to heat stress. Initially, ova were matured at 38.5 or 41.0 degrees C. The consequences of heat stress did not include altered cleavage, but did reduce the proportion of 8- to 16-cell-stage embryos (55.3 vs. 50.6%; SEM +/- 1.9). Although proportionately fewer, compact morulae from heat-stressed ova were equivalent in quality to those from non-heat-stressed ova (2.1 and 2.1; SEM = 0.04). Culture of compact morulae from non-heat-stressed ova at 41.0 degrees C did not affect blastocyst development (71.9 and 71.5%; SEM = 3.0). Furthermore, the development of compact morulae from heat-stressed ova was similar to that of non-heat-stressed ova after culture at 38.5 degrees C (68.2 vs. 71.9 and 71.5%; SEM = 3.0). However, blastocyst development was reduced when compact morulae from heat-stressed ova were cultured at 41.0 degrees C (62.3 vs. 71.9, 71.5 and 68.2; SEM = 3.1). In summary, reduced compaction rates of heat-stressed ova explained in part why fewer develop to the blastocyst stage after fertilization. The thermolability of the few embryos that develop from otherwise developmentally challenged ova emphasizes the importance of minimizing exposure to stressor(s) during oocyte maturation.

Thermoreceptive innervation of human glabrous and hairy skin: a contact heat evoked potential analysis.

PubMed

Granovsky, Yelena; Matre, Dagfinn; Sokolik, Alexander; Lorenz, Jürgen; Casey, Kenneth L

2005-06-01

The human palm has a lower heat detection threshold and a higher heat pain threshold than hairy skin. Neurophysiological studies of monkeys suggest that glabrous skin has fewer low threshold heat nociceptors (AMH type 2) than hairy skin. Accordingly, we used a temperature-controlled contact heat evoked potential (CHEP) stimulator to excite selectively heat receptors with C fibers or Adelta-innervated AMH type 2 receptors in humans. On the dorsal hand, 51 degrees C stimulation produced painful pinprick sensations and 41 degrees C stimuli evoked warmth. On the glabrous thenar, 41 degrees C stimulation produced mild warmth and 51 degrees C evoked strong but painless heat sensations. We used CHEP responses to estimate the conduction velocities (CV) of peripheral fibers mediating these sensations. On hairy skin, 41 degrees C stimuli evoked an ultra-late potential (mean, SD; N wave latency: 455 (118) ms) mediated by C fibers (CV by regression analysis: 1.28 m/s, N=15) whereas 51 degrees C stimuli evoked a late potential (N latency: 267 (33) ms) mediated by Adelta afferents (CV by within-subject analysis: 12.9 m/s, N=6). In contrast, thenar responses to 41 and 51 degrees C were mediated by C fibers (average N wave latencies 485 (100) and 433 (73) ms, respectively; CVs 0.95-1.35 m/s by regression analysis, N=15; average CV=1.7 (0.41) m/s calculated from distal glabrous and proximal hairy skin stimulation, N=6). The exploratory range of the human and monkey palm is enhanced by the abundance of low threshold, C-innervated heat receptors and the paucity of low threshold AMH type 2 heat nociceptors.

Specific heats of lunar surface materials from 90 to 350 degrees Kelvin

USGS Publications Warehouse

Robie, R.A.; Hemingway, B.S.; Wilson, W.H.

1970-01-01

The specific heats of lunar samples 10057 and 10084 returned by the Apollo 11 mission have been measured between 90 and 350 degrees Kelvin by use of an adiabatic calorimeter. The samples are representative of type A vesicular basalt-like rocks and of finely divided lunar soil. The specific heat of these materials changes smoothly from about 0.06 calorie per gram per degree at 90 degrees Kelvin to about 0.2 calorie per gram per degree at 350 degrees Kelvin. The thermal parameter ??=(k??C)-1/2 for the lunar surface will accordingly vary by a factor of about 2 between lunar noon and midnight.

Coral Bleaching Products - Office of Satellite and Product Operations

Science.gov Websites

weeks. One DHW is equivalent to one week of sea surface temperatures one degree Celsius greater than the expected summertime maximum. Two DHWs are equivalent to two weeks at one degree above the expected summertime maximum OR one week of two degrees above the expected summertime maximum. Also called Coral Reef

Response of superoxide dismutase isoenzymes in tomato plants (Lycopersicon esculentum) during thermo-acclimation of the photosynthetic apparatus.

PubMed

Camejo, Daymi; Martí, María del C; Nicolás, Emilio; Alarcón, Juan J; Jiménez, Ana; Sevilla, Francisca

2007-11-01

Seedlings of Lycopersicon esculentum Mill. var. Amalia were grown in a growth chamber under a photoperiod of 16 h light at 25 degrees C and 8 h dark at 20 degrees C. Five different treatments were applied to 30-day-old plants: Control treatment (plants maintained in the normal growth conditions throughout the experimental time), heat acclimation (plants exposed to 35 degrees C for 4 h in dark for 3 days), dark treatment (plants exposed to 25 degrees C for 4 h in dark for 3 days), heat acclimation plus heat shock (plants that previously received the heat acclimation treatment were exposed to 45 degrees C air temperature for 3 h in the light) and dark treatment plus heat shock (plants that previously received the dark treatment were exposed to 45 degrees C air temperature for 3 h in the light). Only the heat acclimation treatment increased the thermotolerance of the photosynthesis apparatus when the heat shock (45 degrees C) was imposed. In these plants, the CO(2) assimilation rate was not affected by heat shock and there was a slight and non-significant reduction in maximum carboxylation velocity of Rubisco (V(cmax)) and maximum electron transport rate contributing to Rubisco regeneration (J(max)). However, the plants exposed to dark treatment plus heat shock showed a significant reduction in the CO(2) assimilation rate and also in the values of V(cmax) and J(max). Chlorophyll fluorescence measurements showed increased thermotolerance in heat-acclimated plants. The values of maximum chlorophyll fluorescence (F(m)) were not modified by heat shock in these plants, while in the dark-treated plants that received the heat shock, the F(m) values were reduced, which provoked a significant reduction in the efficiency of photosystem II. A slight rise in the total superoxide dismutase (SOD) activity was found in the plants that had been subjected to both heat acclimation and heat shock, and this SOD activity was significantly higher than that found in the plants subjected to dark treatment plus heat shock. The activity of Fe-SOD isoenzymes was most enhanced in heat-acclimated plants but was unaltered in the plants that received the dark treatment. Total CuZn-SOD activity was reduced in all treatments. Darkness had an inhibitory effect on the Mn-SOD isoenzyme activity, which was compensated by the effect of a rise in air temperature to 35 degrees C. These results show that the heat tolerance of tomatoplants may be increased by the previous imposition of a moderately high temperature and could be related with the thermal stability in the photochemical reactions and a readjustment of V(cmax) and J(max). Some isoenzymes, such as the Fe-SODs, may also play a role in the development of heat-shock tolerance through heat acclimation. In fact, the pattern found for these isoenzymes in heat-acclimated Amalia plants was similar to that previously described in other heat-tolerant tomato genotypes.

ETR HEAT EXCHANGER BUILDING, TRA644. WORKERS CHECK INTERIOR OF ONE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ETR HEAT EXCHANGER BUILDING, TRA-644. WORKERS CHECK INTERIOR OF ONE OF THE TWELVE HEAT EXCHANGER UNITS. COOLANT FROM ETR WILL ENTER EXCHANGERS AT TEMPERATURE OF 137.5 DEGREES F. AND LEAVE THE SYSTEM AT 110 DEGREES F. SECONDARY WATER WILL ENTER AT 78 DEGREES F. AND LEAVE SYSTEM AT 110 DEGREES F. INL NEGATIVE NO. 56-3712. R.G. Larsen, Photographer, 11/13/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Effect of whole-body and local heating on cutaneous vasoconstrictor responses in humans

NASA Technical Reports Server (NTRS)

Wilson, Thad E.; Cui, Jian; Crandall, Craig G.

2002-01-01

Animal studies suggest that alpha-adrenergic-mediated vasoconstriction is compromised during whole-body heating. The purpose of this study was to identify whether whole-body heating and/or local surface heating reduce cutaneous alpha-adrenergic vasoconstrictor responsiveness in human skin. Protocol I: Six subjects were exposed to neutral skin temperature (i.e., 34 degrees C), whole-body heating, and local heating of forearm skin to increase skin blood flow to the same relative magnitude as that observed during whole-body heating. Protocol II: In eight subjects forearm skin was locally heated to 34, 37, 40, and 42 degrees C. During both protocols, alpha-adrenergic vasoconstrictor responsiveness was assessed by local delivery of norepinephrine (NE) via intradermal microdialysis. Skin blood flow was continuously monitored over each microdialysis membrane via laser-Doppler flowmetry. In protocol I, whole-body and local heating caused similar increases in cutaneous vascular conductance (CVC). The EC50 (log NE dose) of the dose-response curves for both whole body (-4.2 +/- 0.1 M) and local heating (-4.7 +/- 0.4 M) were significantly greater (i.e., high dose required to cause 50% reduction in CVC) relative to neutral skin temperature (- 5.6 +/- 0.0 M; P<0.05 for both). In both local and whole-body heated conditions CVC did not return to pre-heating values even at the highest dose of NE. In protocol II, calculated EC50 for 34, 37, 40, and 42 degrees C local heating was - 5.5 +/- 0.4, -4.6 +/- 0.3, -4.5 +/- 0.3, - 4.2 +/- 0.4 M, respectively. Statistical analyses revealed that the EC50 for 37,40 and 42 degrees C were significantly greater than the EC50 for 34 degrees C. These results indicate that even during administration of high concentrations of NE, alpha-adrenergic vasoconstriction does not fully compensate for local heating and whole-body heating induced vasodilatation in young, healthy subjects. Moreover, these data suggest that elevated local temperatures, above 37 degrees C, and whole-body heating similarly attenuate cutaneous alpha-adrenergic vasoconstriction responsiveness.

Design and performance of a new induction furnace for heat treatment of superconducting radiofrequency niobium cavities

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

Dhakal, Pashupati; Ciovati, Gianluigi; Myneni, Ganapati Rao

2012-06-15

Superconducting radio frequency (SRF) cavities made of high purity niobium (Nb) are the building blocks of many modern particle accelerators. The fabrication process includes several cycles of chemical and heat treatment at low ({approx}120 Degree-Sign C) and high ({approx}800 Degree-Sign C) temperatures. In this contribution, we describe the design and performance of an ultra-high-vacuum furnace which uses an induction heating system to heat treat SRF cavities. Cavities are heated by radiation from the Nb susceptor. By using an all-niobium hot zone, contamination of the Nb cavity by foreign elements during heat treatment is minimized and allows avoiding subsequent chemical etching.more » The furnace was operated up to 1400 Degree-Sign C with a maximum pressure of {approx}1 Multiplication-Sign 10{sup -5} Torr and the maximum achievable temperature is estimated to be higher than 2000 Degree-Sign C. Initial results on the performance of a single cell 1.5 GHz cavity made of ingot Nb heat treated at 1200 Degree-Sign C using this new induction furnace and without subsequent chemical etching showed a reduction of the RF losses by a factor of {approx}2 compared to cavities made of fine-grain Nb which underwent standard chemical and heat treatments.« less

The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men.

PubMed

Mieusset, R; Bujan, L

1994-08-01

A preliminary assessment of the contraceptive efficacy of a daily mild increase (1-2 degrees C) in testicular temperature during waking hours is reported in nine couples using two techniques of non-surgical fixation of the testes close to the inguinal canal. With technique 1, immobilization was achieved by passing the penis and the empty scrotum through a hole made in close-fitting underwear; there was one pregnancy, from a man who stopped the heating after 7 weeks, for 42 cycles of exposure in three couples. With technique 2, immobilization was achieved by adding a ring of soft material surrounding the hole in the underwear; there was no pregnancy for 117 cycles of exposure in six couples. Reversibility and safety were assessed. These preliminary results suggest that a daily mild increase in testicular temperature could be a potential contraceptive method for men.

Increased hospital admissions associated with extreme-heat exposure in King County, Washington, 1990-2010

PubMed Central

Isaksen, Tania Busch; Yost, Michael G.; Hom, Elizabeth K.; Ren, You; Lyons, Hilary; Fenske, Richard A.

2016-01-01

Increased morbidity and mortality have been associated with extreme heat events, particularly in temperate climates. Few epidemiologic studies have considered the impact of extreme heat events on hospitalization rates in the Pacific Northwest region. This study quantifies the historical (May to September 1990-2010) heat-morbidity relationship in the most populous Pacific Northwest County -King County, Washington. A relative risk (RR) analysis was used to explore the association between heat and all non-traumatic hospitalizations on 99th percentile heat days, while a time series analysis using a piece-wise linear model approximation was used to estimate the effect that heat’s intensity has on hospitalizations, adjusted for temporal trends and day of the week. A non-statistically significant 2% [95% CI: 1.02 (0.98, 1.05)] increase in hospitalization risk, on a heat day versus a non-heat day, was noted for all-ages, all non-traumatic causes. When considering the effect heat intensity has on admissions, we found a statistically significant 1.59% (95% CI: 0.9%, 2.29%) increase in admissions per degree increase in humidex above 37.4 °C. Admissions stratified by cause and age produced statistically significant results with both relative risk and time series analyses for nephritis and nephrotic syndromes, acute renal failure and natural heat exposure hospitalizations. This study demonstrates that heat, expressed as humidex, is associated with increased hospital admissions. When stratified by age and cause of admission, the non-elderly (less than 85) age groups experience significant risk for: nephritis and nephrotic syndromes, acute renal failure, natural heat exposure, COPD and asthma hospitalizations. PMID:25719287

Climate Fundamentals for Solar Heating.

ERIC Educational Resources Information Center

Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

The design of any solar heating system is influenced heavily by climate; in this bulletin, information on climate as related to solar heating is as related to solar heating is provided. Topics discussed include: (1) solar radiation; (2) degree days; (3) climate and calculations which make use of solar radiation and degree days; and (4)…

The Effect of Seasonal Thermal Stress on Lipid Mobilisation, Antioxidant Status and Reproductive Performance in Dairy Cows.

PubMed

Turk, R; Podpečan, O; Mrkun, J; Flegar-Meštrić, Z; Perkov, S; Zrimšek, P

2015-08-01

Heat stress is a major factor contributing to low fertility of dairy cows with a great economic impact in dairy industry. Heat-stressed dairy cows usually have reduced nutrient intake, resulting in a higher degree of negative energy balance (NEB). The aim of this study was to investigate the seasonal thermal effect on lipid metabolism, antioxidant activity and reproductive performance in dairy cows. Thirty-two healthy dairy heifers were included in the study. According to the ambient temperature, animals were divided into two groups: winter (N = 14) and summer season (N = 18). Metabolic parameters, paraoxonase-1 (PON1) activity and total antioxidant status (TAS) were monitored at the time of insemination (basal values) and from 1 week before until 8 weeks after calving. Number of services per conception and calving-to-conception (CC) interval were calculated from the farm recording data. Serum triglyceride, non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) concentrations were significantly increased after calving in summer compared to winter, indicating higher degree of NEB in cows during summer. PON1 activity was significantly decreased after calving in both summer and winter group. TAS concentration was significantly lower in summer than that in winter. A significantly higher number of services were needed for conception in summer compared to winter, and CC interval was significantly longer in summer than that in winter as well. Additionally, reproductive performance significantly correlated with the severity of NEB, suggesting that lipid mobilization and lower antioxidant status contributed to poor reproduction ability in dairy cows during hot months. © 2015 Blackwell Verlag GmbH.

Thermal inactivation of poliovirus type 1 in water, milk and yoghurt.

PubMed

Strazynski, Marco; Krämer, Johannes; Becker, Barbara

2002-03-25

Loss of infectivity of poliovirus type 1, strain Sabin, during heating, freezing, and storage in water, milk and yoghurt was determined by plaque-titration in Vero cell cultures. The heating experiments simulated the conditions arising during the processing of milk and yoghurt, for example high-temperature heating (95 degrees C, 15 and 30 s), short-time pasteurization (72 degrees C, 15 and 30 s), long-time pasteurization (62 degrees C, 30 min), and yoghurt-fermentation (42 degrees C, 30 min and 180 min). Only high-temperature heating, long-time pasteurization and short-time pasteurization for 30 s proved to be reliable methods of inactivating polioviruses present in water, milk and yoghurt completely. Short-time pasteurization for 15 s and the conditions of yoghurt-fermentation failed to cause complete inactivation of polioviruses. Additionally, polioviruses mixed in milk or yoghurt withstood these procedures with significantly lower reductions of infectivity than in water. Heating at 55 degrees C for 30 min resulted in complete inactivation of polioviruses, regardless of the suspending medium. The infectivity of polioviruses is scarcely affected by freezing (-20 degrees C, 30 min) and storage (24 days) at low temperatures (4 degrees C) and high humidity (a(w) = 0.99).

A comparison of root surface temperatures using different obturation heat sources.

PubMed

Lee, F S; Van Cura, J E; BeGole, E

1998-09-01

This study compared root surface temperatures produced during warm vertical obturation using the System B Heat Source (SB), the Touch 'n Heat device (TH), and a flame-heated carrier (FH). The root canals of 30 maxillary incisor, premolar, and mandibular incisor teeth were prepared; divided into three groups; and obturated using each heat source. A thermocouple placed 2 mm below the cementoenamel junction transferred the temperature rise on the external root surface to a digital thermometer. SB surface temperature rise was < 10 degrees C for all experimental teeth. TH temperature rise in maxillary incisors and premolars was < 10 degrees C; however, > 10 degrees C was observed for mandibular incisors. FH produced a > 10 degrees C surface temperature rise in all experimental teeth. The critical level of root surface heat required to produce irreversible bone damage is believed to be > 10 degrees C. The findings of this study suggest that warm vertical condensation with the SB should not damage supporting periradicular tissues. However, caution should be used with TH and FH on mandibular incisors.

Measurement of temperature-dependent specific heat of biological tissues.

PubMed

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

2005-02-01

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

Effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester.

PubMed

Espinosa-Solares, Teodoro; Valle-Guadarrama, Salvador; Bombardiere, John; Domaschko, Max; Easter, Michael

2009-05-01

The effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester treating chicken litter, under thermophilic conditions, has been studied. Heating strategy was evaluated using three different spans (0.2 degrees C, 0.6 degrees C, and 1.0 degree C) for triggering the temperature control system from target temperature (56.7 degrees C). The hydraulic retention time in the pilot plant digester was in the range of 32 to 37 days, varying the total solids concentration fed from 5% to 6%. The results showed that under the experimental conditions, heating was the most energy-demanding process with 95.5% of the energy used. Increments up to 7.5% and 3.8%, respectively, on mechanical and heating power consumption, were observed as the span, for triggering the temperature control system from target temperature, was increased. Under the experimental conditions studied here, an increment of 30.6% on the global biodigester performance index was observed when a span of 1.0 degree C was compared to the one of 0.2 degrees C.

Heat shock protein 70 in the rat nasal cavity: localisation and response to hyperthermia.

PubMed

Simpson, Sharon A; Alexander, David J; Reed, Celia J

2004-06-01

Heat shock proteins (HSPs) are a group of proteins that are rapidly induced in response to physiological stress, including hyperthermia and exposure to toxicants. Thus they may provide a useful index of toxicity in in vitro systems for screening for toxicity. We have recently developed a rat nasal explant system for investigating upper respiratory tract toxicity, and the aims of this study were to localise HSP70 within the rat nasal cavity and to characterise its response to hyperthermia. Constitutively, HSP70 was found to be predominantly localised to the sustentacular cells, basal cells and Bowman's glands of the olfactory epithelium (OE), with the most intense immunohistochemical staining at levels 3 and 4 of the posterior of the rat nasal cavity. Ethmoturbinates (ETs) and liver slices were exposed to heat shock (37 degrees and 43 degrees C, respectively) for 45 min and then returned to normal culture temperatures (31 degrees and 37 degrees C, respectively) for 24 h. In ETs, HSP72 was maximally induced 4-fold at 4 h after heat shock, and levels then returned to those of control tissue. ATP concentrations were markedly decreased up to 4 h after heat shock and then returned to control levels. In contrast, HSP72 levels in liver slices increased and ATP levels decreased steadily throughout the 24 h culture period. ETs were also able to withstand a 45-min heat shock at 43 degrees C, that is 12 degrees C above normal culture temperature. Incubation of ETs with cycloheximide prior to heat shock reduced the ability of the OE to recover from heat shock at 37 degrees C. Thus the OE of the rat nasal cavity expresses HSP72, and this protein appears to play an important role in the ability of the tissue to withstand hyperthermia.

Heat loss through the glabrous skin surfaces of heavily insulated, heat-stressed individuals.

PubMed

Grahn, D A; Dillon, J L; Heller, H C

2009-07-01

Insulation reduces heat exchange between a body and the environment. Glabrous (nonhairy) skin surfaces (palms of the hands, soles of the feet, face, and ears) constitute a small percentage of total body surface area but contain specialized vascular structures that facilitate heat loss. We have previously reported that cooling the glabrous skin surfaces is effective in alleviating heat stress and that the application of local subatmospheric pressure enhances the effect. In this paper, we compare the effects of cooling multiple glabrous skin surfaces with and without vacuum on thermal recovery in heavily insulated heat-stressed individuals. Esophageal temperatures (T(es)) and heart rates were monitored throughout the trials. Water loss was determined from pre- and post-trial nude weights. Treadmill exercise (5.6 km/h, 9-16% slope, and 25-45 min duration) in a hot environment (41.5 degrees C, 20-30% relative humidity) while wearing insulating pants and jackets was used to induce heat stress (T(es)>or=39 degrees C). For postexercise recovery, the subjects donned additional insulation (a balaclava, winter gloves, and impermeable boot covers) and rested in the hot environment for 60 min. Postexercise cooling treatments included control (no cooling) or the application of a 10 degrees C closed water circulating system to (a) the hand(s) with or without application of a local subatmospheric pressure, (b) the face, (c) the feet, or (d) multiple glabrous skin regions. Following exercise induction of heat stress in heavily insulated subjects, the rate of recovery of T(es) was 0.4+/-0.2 degrees C/h(n=12), but with application of cooling to one hand, the rate was 0.8+/-0.3 degrees C/h(n=12), and with one hand cooling with subatmospheric pressure, the rate was 1.0+/-0.2 degrees C/h(n=12). Cooling alone yielded two responses, one resembling that of cooling with subatmospheric pressure (n=8) and one resembling that of no cooling (n=4). The effect of treating multiple surfaces was additive (no cooling, DeltaT(es)=-0.4+/-0.2 degrees C; one hand, -0.9+/-0.3 degrees C; face, -1.0+/-0.3 degrees C; two hands, -1.3+/-0.1 degrees C; two feet, -1.3+/-0.3 degrees C; and face, feet, and hands, -1.6+/-0.2 degrees C). Cooling treatments had a similar effect on water loss and final resting heart rate. In heat-stressed resting subjects, cooling the glabrous skin regions was effective in lowering T(es). Under this protocol, the application of local subatmospheric pressure did not significantly increase heat transfer per se but, presumably, increased the likelihood of an effect.

Method for heat treating iron-nickel-chromium alloy

DOEpatents

Merrick, Howard F.; Korenko, Michael K.

1982-01-01

A method for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a bimodal distribution of gamma prime phase within a network of dislocations, the alloy consisting essentially of about 25% to 45% nickel, 10% to 16% chromium, 1.5% to 3% of an element selected from the group consisting of molybdenum and niobium, about 2% titanium, about 3% aluminum, and the remainder substantially all iron. To obtain optimum results, the alloy is heated to a temperature of 1025.degree. C. to 1075.degree. C. for 2-5 minutes, cold-worked about 20% to 60%, aged at a temperature of about 775.degree. C. for 8 hours followed by an air-cool, and then heated to a temperature in the range of 650.degree. C. to 700.degree. C. for 2 hours followed by an air-cool.

Effect of heating-ventilation-air conditioning system sanitation on airborne fungal populations in residential environments.

PubMed

Garrison, R A; Robertson, L D; Koehn, R D; Wynn, S R

1993-12-01

Commercial air duct sanitation services are advertised to the public as being effective in reducing indoor aeroallergen levels despite the absence of published supporting data. Eight residential heat-ventilation-air conditioning (HVAC) systems in six homes and seven HVAC systems in five homes in winter and summer, respectively, were sampled to determine fungal colony forming units (CFUs) prior to and after an HVAC sanitation procedure was performed by a local company. Two houses in which no sanitation procedure was performed served as controls in each study phase. Two sample sets were obtained at each HVAC system prior to cleaning in order to determine baseline CFU levels. The test HVAC systems were then cleaned, and the HVAC systems allowed to operate as desired by the residents. Posttreatment sampling was performed 48 hours and then weekly after cleaning for 8 weeks. The HVAC systems were analyzed by exposing sterile 2% malt extract media plates at a 90-degree angle to the air flow at the air supply and air return vents. The baseline CFUs were similar in the control and study houses. Eight weeks after sanitation, the study houses demonstrated an overall CFU reduction of 92% during winter and 84% during summer. No reduction in CFU values was observed over the 8-week study period for the houses selected as controls. Further, HVAC sanitation appeared to reduce the number of fungal colonies entering and leaving the HVAC system, suggesting that the HVAC contained a significant percentage of the total fungal load in these homes. These data suggest that HVAC sanitation may be an effective tool in reducing airborne fungal populations in residential environments.

To cool, but not too cool: that is the question--immersion cooling for hyperthermia.

PubMed

Taylor, Nigel A S; Caldwell, Joanne N; Van den Heuvel, Anne M J; Patterson, Mark J

2008-11-01

Patient cooling time can impact upon the prognosis of heat illness. Although ice-cold-water immersion will rapidly extract heat, access to ice or cold water may be limited in hot climates. Indeed, some have concerns regarding the sudden cold-water immersion of hyperthermic individuals, whereas others believe that cutaneous vasoconstriction may reduce convective heat transfer from the core. It was hypothesized that warmer immersion temperatures, which induce less powerful vasoconstriction, may still facilitate rapid cooling in hyperthermic individuals. Eight males participated in three trials and were heated to an esophageal temperature of 39.5 degrees C by exercising in the heat (36 degrees C, 50% relative humidity) while wearing a water-perfusion garment (40 degrees C). Subjects were cooled using each of the following methods: air (20-22 degrees C), cold-water immersion (14 degrees C), and temperate-water immersion (26 degrees C). The time to reach an esophageal temperature of 37.5 degrees C averaged 22.81 min (air), 2.16 min (cold), and 2.91 min (temperate). Whereas each of the between-trial comparisons was statistically significant (P < 0.05), cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45-s cooling time difference would have any meaningful physiological or clinical implications. It is assumed that this rapid heat loss was due to a less powerful peripheral vasoconstrictor response, with central heat being more rapidly transported to the skin surface for dissipation. Although the core-to-water thermal gradient was much smaller with temperate-water cooling, greater skin and deeper tissue blood flows would support a superior convective heat delivery. Thus, a sustained physiological mechanism (blood flow) appears to have countered a less powerful thermal gradient, resulting in clinically insignificant differences in heat extraction between the cold and temperate cooling trials.

Characterization of the nature of photosynthetic recovery of wheat seedlings from short-term dark heat exposures and analysis of the mode of acclimation to different light intensities.

PubMed

Kreslavski, Vladimir; Tatarinzev, Nikolai; Shabnova, Nadezhda; Semenova, Galina; Kosobryukhov, Anatoli

2008-10-09

The nature of photosynthetic recovery was investigated in 10-d-old wheat (Triticum aestivum L., cv. Moskovskaya-35) seedlings exposed to temperatures of 40 and 42 degrees C for 20 min and to temperature 42 degrees C for 40 min in the dark. The aftereffect of heat treatment was monitored by growing the heat-treated plants in low/moderate/high light at 20 degrees C for 72h. The net photosynthetic rates (P(N)) and the fluorescence ratios F(v)/F(m) were evaluated in intact primary leaves and the rates of cyclic and non-cyclic photophosphorylation were measured in the isolated thylakoids. At least two temporally separated steps were identified in the path of recovery from heat stress at 40 and 42 degrees C in the plants growing in high and moderate/high light, respectively. Both photochemical activity of the photosystem II (PSII) and the activity of CO(2) assimilation system were lowered during the first step in comparison with the corresponding activities immediately after heat treatment. During the second step, the photosynthetic activities completely or partly recovered. Recovery from heat stress at 40 degrees C was accompanied by an appreciably higher rate of cyclic photophosphorylation in comparison with control non-heated seedlings. In pre-heated seedlings, the tolerance of the PSII to photoinhibition was higher than in non-treated ones. The mode of acclimation to different light intensities after heat exposures is analyzed.

Evaluation of heat treatment schedules for emerald ash borer (Coleoptera: Buprestidae).

PubMed

Myers, Scott W; Fraser, Ivich; Mastro, Victor C

2009-12-01

The thermotolerance of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), was evaluated by subjecting larvae and prepupae to a number of time-temperature regimes. Three independent experiments were conducted during 2006 and 2007 by heating emerald ash borer infested firewood in laboratory ovens. Heat treatments were established based on the internal wood temperature. Treatments ranged from 45 to 65 degrees C for 30 and 60 min, and the ability of larvae to pupate and emerge as adults was used to evaluate the success of each treatment. A fourth experiment was conducted to examine heat treatments on exposed prepupae removed from logs and subjected to ambient temperatures of 50, 55, and 60 degrees C for 15, 30, 45, and 60 min. Results from the firewood experiments were consistent in the first experiment. Emergence data showed emerald ash borer larvae were capable of surviving a temperatures-time combination up to 60 degrees C for 30 min in wood. The 65 degrees C for 30 min treatment was, however, effective in preventing emerald ash borer emergence on both dates. Conversely, in the second experiment using saturated steam heat, complete mortality was achieved at 50 and 55 degrees C for both 30 and 60 min. Results from the prepupae experiment showed emerald ash borer survivorship in temperature-time combinations up to 55 degrees C for 30 min, and at 50 degrees C for 60 min; 60 degrees C for 15 min and longer was effective in preventing pupation in exposed prepupae. Overall results suggest that emerald ash borer survival is variable depending on heating conditions, and an internal wood temperature of 60 degrees C for 60 min should be considered the minimum for safe treatment for firewood.

The effects of heat and massage application on autonomic nervous system.

PubMed

Lee, Young-Hee; Park, Bit Na Ri; Kim, Sung Hoon

2011-11-01

The objective of this study is to evaluate the effects of heat and massage application on autonomic nervous system. One hundred thirty-nine subjects volunteered and completed this study. Heat and massage was daily applied for 40 minutes, 5 days a week for 2 weeks. Primary-dependent measures included heart rate variability, sympathetic skin response, and serum cortisol and norepinephrine levels. Serum cortisol levels were significantly decreased at 2 weeks compared to baseline (p=0.003). Plasma norepinephrine levels at 4 weeks were significantly decreased compared to baseline (p=0.010). Heart rate, using the power spectra, increased significantly after 2 weeks compared to baseline. Of autonomic nerve conduction measures, latency was significantly increased at 2 and 4 weeks compared to baseline (p=0.023, 0.012), and amplitude was significantly decreased at 4 weeks compared to baseline (p=0.008). There were no serious adverse events such as burns or other major complications. The results of this study suggest that heat and massage applications provide relaxation to the autonomic nervous system without serious adverse events.

Determination of the boiling-point distribution by simulated distillation from n-pentane through n-tetratetracontane in 70 to 80 seconds.

PubMed

Lubkowitz, Joaquin A; Meneghini, Roberto I

2002-01-01

This work presents the carrying out of boiling-point distributions by simulated distillation with direct-column heating rather than oven-column heating. Column-heating rates of 300 degrees C/min are obtained yielding retention times of 73 s for n-tetratetracontane. The calibration curves of the retention time versus the boiling point, in the range of n-pentane to n-tetratetracontane, are identical to those obtained by slower oven-heating rates. The boiling-point distribution of the reference gas oil is compared with that obtained with column oven heating at rates of 15 to 40 degrees C/min. The results show boiling-point distribution values nearly the same (1-2 degrees F) as those obtained with oven column heating from the initial boiling point to 80% distilled off. Slightly higher differences are obtained (3-4 degrees F) for the 80% distillation to final boiling-point interval. Nonetheless, allowed consensus differences are never exceeded. Precision of the boiling-point distributions (expressed as standard deviations) are 0.1-0.3% for the data obtained in the direct column-heating mode.

Influence of modified atmospheric storage, lactic acid, and NaCl on survival of sublethally heat-injured Listeria monocytogenes.

PubMed

Williams, R C; Golden, D A

2001-03-20

The effect of package atmosphere on survival of uninjured and sublethally heat-injured Listeria monocytogenes, inoculated onto tryptose phosphate agar containing 0.85% lactic acid and 2% NaCl (TPALAS) was investigated. Inoculated TPALAS plates were packaged in air, 100% N2 (N2), 30% CO2-70% N2 (CO2-N2), and vacuum and stored at 4 and 20 degrees C for up to 31 days. Recovery of L. monocytogenes from TPALAS was influenced by the injury status (i.e., injured and uninjured) of the inoculum, storage atmosphere (air, N2, CO2-N2, and vacuum), storage temperature (4 and 20 degrees C), and recovery media [tryptose phosphate agar (TPA) and modified Oxford agar (MOX)] (P <0.05). Overall, storage at 4 degrees C supported greater survival than storage at 20 degrees C (P< 0.05). Uninjured L. monocytogenes stored at 4 degrees C was recovered on TPA better than sublethally heat-injured L. monocytogenes stored at 40 degrees C (P < 0.05). Recovery of sublethally heat-injured L. monocytogenes stored at 4 degrees C followed the order N2 > CO2-N2 > air > vacuum (P < 0.05), whereas recovery of uninjured L. monocyrogenes stored at 4 degrees C followed the order N2 > CO2-N2 > vacuum > air (P < 0.05). Air and vacuum atmospheres supported greater survival of uninjured and heat-injured L. monocytogenes than N2 and CO2-N2 atmospheres at 20 degrees C (P < 0.05). Recovery of sublethally heat-injured L. monocytogenes stored at 20 degrees C followed the order vacuum > air> CO2-N2 = N2 (P <0.05), whereas recovery of uninjured L. monocytogenes stored at 20 degrees C followed the order vacuum > air> CO2-N2 > N2 (P<0.05). Uninjured L. monocytogenes stored under N2 at 4 degrees C was recovered best, whereas sublethally heat-injured L. monocytogenes stored under N2 at 20 degrees C was recovered poorest (P < 0.05). Factors such as package atmosphere and storage temperature, involved in the production, storage, and distribution of fermented foods must be thoroughly evaluated when determining strategies for control and detection of L. monocytogenes in such products.

Comparison of IR thermography and thermocouple measurement of heat loss from rabbit pinna.

PubMed

Mohler, F S; Heath, J E

1988-02-01

The temperature of the pinnae of male New Zealand White rabbits was measured by use of infrared thermography. At ambient temperatures of 15, 20, and 25 degrees C, the average pinna temperatures were 23.0, 28.7, and 36.2 degrees C, respectively. From these temperatures, average heat loss from the total pinna surface area was calculated to be 2.8, 3.3, and 4.4 W, respectively. Preoptic temperature changes also affect the vasomotor state of the rabbit. At an ambient temperature of 20 degrees C, cooling the preoptic area of the rabbit by approximately 1 degree C resulted in an average pinna temperature of 26.5 degrees C and a heat loss of 2.4 W. Heating the preoptic area by approximately 1 degree C resulted in an average pinna temperature of 33.5 degrees C and a heat loss of 5.4 W. Finally, pinna temperatures were measured by use of a thermocouple and infrared thermography simultaneously. When the pinnae were vasodilated, the thermocouple measurements were consistently higher than the pinna surface temperatures measured thermographically. When the pinnae were vasoconstricted, the thermocouple measurements were consistently lower than the pinna surface temperatures measured thermographically. The discrepancy between the two methods of measurement is discussed.

Solar heat receiver

DOEpatents

Hunt, Arlon J.; Hansen, Leif J.; Evans, David B.

1985-01-01

A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

Rapid PCR amplification using a microfluidic device with integrated microwave heating and air impingement cooling.

PubMed

Shaw, Kirsty J; Docker, Peter T; Yelland, John V; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2010-07-07

A microwave heating system is described for performing polymerase chain reaction (PCR) in a microfluidic device. The heating system, in combination with air impingement cooling, provided rapid thermal cycling with heating and cooling rates of up to 65 degrees C s(-1) and minimal over- or under-shoot (+/-0.1 degrees C) when reaching target temperatures. In addition, once the required temperature was reached it could be maintained with an accuracy of +/-0.1 degrees C. To demonstrate the functionality of the system, PCR was successfully performed for the amplification of the Amelogenin locus using heating rates and quantities an order of magnitude faster and smaller than current commercial instruments.

Effect of different non-chloride sodium sources on the performance of heat-stressed broiler chickens.

PubMed

Ahmad, T; Mushtaq, T; Mahr-Un-Nisa; Sarwar, M; Hooge, D M; Mirza, M A

2006-06-01

1. One hundred and eighty 1-d-old broiler chicks were used to evaluate the effect upon broiler performance during severely hot summer months of three different sodium salts: sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4), in starter and finisher diets having an identical electrolyte balance (DEB) of 250 mEq/kg. 2. The non-chloride sodium salts were added to contribute the same amount of sodium and were substituted at the expense of builder's sand in the basal diets containing common salt (NaCl) as Na and Cl source. 3. Each diet was fed to three experimental units having 15 chicks each until 42 d of age. Severe heat-stress conditions, maintained in the rearing room, were indicated by high average weekly room temperature (minimum 29.3 degrees C; maximum 38.0 degrees C). 4. Diets containing sodium salts gave better body weight gain, feed intake and feed to gain ratio than the control diet. Sodium salts also enhanced water intake as well as water to feed intake ratio. This effect was more pronounced in broilers fed NaHCO3 supplement (with NaCl in the basal diets). 5. The increased water intake resulted in lower body temperature in heat-stressed birds fed NaHCO3 supplemented diet than in birds fed other sodium salts. A lower mortality rate was noted with NaHCO3 (15.15%), Na2CO3 (13.64%) and Na2SO4 (15.15%) supplements than with the control (33.33%) treatment. 6. Better carcase and parts yield were observed in sodium supplemented broilers. Sodium salts reduced the alkalotic pH and enhanced the blood sodium content, which ultimately improved the blood electrolyte balance and overall performance of heat-stressed broilers. 7. Supplementing broiler diets with sodium salts improved the live performance of heat-stressed broilers and better productive performance was noted with NaHCO3 than other sodium supplements.

Effect of hyperthermia on the repair of sublethal radiation damage in normal and membrane fatty acid substituted fibroblasts

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

Wolters, H.; Kelholt, D.; Konings, A.W.

1987-02-01

The interaction of heat and X irradiation was studied in normal and polyunsaturated fatty acid (PUFA) substituted mouse fibroblast LM cells. As a result of the substitution the membranes of the PUFA cells were more fluid than the membranes of the normal cells. Three different heat doses were applied (60 min 42 degrees C, 20 min 43 degrees C, and 10 min 44 degrees C) in combination with single or split doses of X rays. Heat radiosensitization was the largest for the 60 min 42 degrees C treatment. Heat radiosensitization and the heat-induced inhibition of the rate of sublethal damagemore » repair were the same for the normal and the PUFA cells. It is concluded from the experiments reported that the processes of hyperthermic inhibition of SLD repair and hyperthermic radiosensitization are independent of membrane fluidity and membrane fatty acid composition.« less

Influence of Hot-Working Conditions on High-Temperature Properties of a Heat-Resistant Alloy

NASA Technical Reports Server (NTRS)

Ewing, John F; Freeman, J W

1957-01-01

The relationships between conditions of hot-working and properties at high temperatures and the influence of the hot-working on response to heat treatment were investigated for an alloy containing nominally 20 percent molybdenum, 2 percent tungsten, and 1 percent columbium. Commercially produced bar stock was solution-treated at 2,200 degrees F. to minimize prior-history effects and then rolled at temperatures of 2,200 degrees, 2,100 degrees, 2,000 degrees, 1,800 degrees, and 1,600 degrees F. Working was carried out at constant temperature and with incremental decreases in temperature simulating a falling temperature during hot-working. In addition, a few special repeated cyclic conditions involving a small reduction at high temperature followed by a small reduction at a low temperature were used to study the possibility of inducing very low strengths by the extensive precipitation accompanying such properties. Most of the rolling was done in open passes with a few check tests being made with closed passes. Heat treatments at both 2,050 degrees and 2,200 degrees F. subsequent to working were used to study the influence on response to heat treatment.

Biochemical changes in response to intensive resistance exercise training in the elderly.

PubMed

Bautmans, Ivan; Njemini, Rose; Vasseur, Sabine; Chabert, Hans; Moens, Lisa; Demanet, Christian; Mets, Tony

2005-01-01

It is assumed that low-grade inflammation, characterized by increased circulating IL-6 and TNF-alpha, is related to the development of sarcopenia. Physical exercise, especially high intensity resistance training, has been shown to be effective in restoring the strength deficit in the elderly. Intensive exercise is accompanied by significant release of IL-6 and TNF-alpha into the blood circulation, but does not result in muscle wasting. Exercise-induced changes in heat-shock protein (Hsp), responsible for cellular protection during stressful situations, might interfere with the acute phase reaction and muscle adaptation. To investigate if intensive strength training in elderly persons induces changes in Hsp70 expression, and if these changes are related to changes in the acute phase reaction or muscle adaptation. 31 elderly persons (aged 68.4+/-5.4 years) performed 6 weeks' intensive strength training. At baseline and after 6 weeks, muscle strength, functional performance (physical activity profile, 6-min walk, 30- second chair stand, grip strength, chair sit & reach and back scratch), linear isokinetic leg extension, circulating IL-6, TNF-alpha, IL-10 and TGF-beta, and Hsp70 in monocytes (M) and lymphocytes (L) immediately after sampling (IAS), after incubation at 37 and 42 degrees C were determined. In 12 participants, cytokines were determined in untrained and trained conditions before and after a single training session. After 6 weeks' training, muscle strength and functional performance improved significantly, together with decreased Hsp70 IAS and Hsp70 37 degrees C and increased Hsp70 42 degrees C (all p<0.05). Strength gains correlated positively with baseline Hsp70 37 degrees C and training-induced changes of Hsp70 42 degrees C in M and L. In an untrained condition, training induced an increase of IL-6 (p<0.05) and a tendency of IL-10 to decrease (p=0.06). In a trained condition the decrease of IL-10 disappeared. Baseline physical activity and 6-min walk distance correlated negatively with circulating IL-6 (p<0.05); except for a negative correlation between TGF-beta and Hsp70 37 degrees C L (p<0.05), no significant relationships were found between cytokines and Hsp70. After the training program, Hsp70 37 degrees C was negatively related to circulating TNF-alpha, IL-10 and TGF-beta. Strength training in the elderly induces changes in Hsp70 expression, associated to strength gains and circulating cytokines. Copyright (c) 2005 S. Karger AG, Basel.

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

PubMed Central

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

1984-01-01

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

Comparison of forced-air warming systems with upper body blankets using a copper manikin of the human body.

PubMed

Bräuer, A; English, M J M; Steinmetz, N; Lorenz, N; Perl, T; Braun, U; Weyland, W

2002-09-01

Forced-air warming with upper body blankets has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with upper body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of eight complete upper body warming systems and to gain more insight into the principles of forced-air warming. Heat transfer of forced-air warmers can be described as follows: Qdot;=h. DeltaT. A, where Qdot;= heat flux [W], h=heat exchange coefficient [W m-2 degrees C-1], DeltaT=temperature gradient between the blanket and surface [ degrees C], and A=covered area [m2]. We tested eight different forced-air warming systems: (1) Bair Hugger and upper body blanket (Augustine Medical Inc. Eden Prairie, MN); (2) Thermacare and upper body blanket (Gaymar Industries, Orchard Park, NY); (3) Thermacare (Gaymar Industries) with reusable Optisan upper body blanket (Willy Rüsch AG, Kernen, Germany); (4) WarmAir and upper body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (5) Warm-Gard and single use upper body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (6) Warm-Gard and reusable upper body blanket (Luis Gibeck AB); (7) WarmTouch and CareDrape upper body blanket (Mallinckrodt Medical Inc., St. Luis, MO); and (8) WarmTouch and reusable MultiCover trade mark upper body blanket (Mallinckrodt Medical Inc.) on a previously validated copper manikin of the human body. Heat flux and surface temperature were measured with 11 calibrated heat flux transducers. Blanket temperature was measured using 11 thermocouples. The temperature gradient between the blanket and surface (DeltaT) was varied between -8 and +8 degrees C, and h was determined by linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, as similar mean skin surface temperatures have been found in volunteers. The covered area was estimated to be 0.35 m2. Total heat flow from the blanket to the manikin was different for surface temperatures between 36 and 38 degrees C. At a surface temperature of 36 degrees C the heat flows were higher (4-26.6 W) than at surface temperatures of 38 degrees C (2.6-18.1 W). The highest total heat flow was delivered by the WarmTouch trade mark system with the CareDrape trade mark upper body blanket (18.1-26.6 W). The lowest total heat flow was delivered by the Warm-Gard system with the single use upper body blanket (2.6-4 W). The heat exchange coefficient varied between 15.1 and 36.2 W m-2 degrees C-1, and mean DeltaT varied between 0.5 and 3.3 degrees C. We found total heat flows of 2.6-26.6 W by forced-air warming systems with upper body blankets. However, the changes in heat balance by forced-air warming systems with upper body blankets are larger, as these systems are not only transferring heat to the body but are also reducing heat losses from the covered area to zero. Converting heat losses of approximately 37.8 W to heat gain, results in a 40.4-64.4 W change in heat balance. The differences between the systems result from different heat exchange coefficients and different mean temperature gradients. However, the combination of a high heat exchange coefficient with a high mean temperature gradient is rare. This fact offers some possibility to improve these systems.

Experimental studies on a new bioactive material: HAIonomer cements.

PubMed

Yap, A U J; Pek, Y S; Kumar, R A; Cheang, P; Khor, K A

2002-02-01

The lack of exotherm during setting, absence of monomer and improved release of incorporated therapeutic agents has resulted in the development of glass ionomer cements (GICs) for biomedical applications. In order to improve biocompatibility and biomechanically match GICs to bone, hydroxyapatite-ionomer (HAIonomer) hybrid cements were developed. Ultra-fine hydroxyapatite (HA) powders were produced using a new induction spraying technique that utilizes a radio-frequency source to spheriodize an atomized suspension containing HA crystallites. The spheriodized particulates were then held at 800 degrees C for 4 h in a carbolite furnace using a heating and cooling rate of 25 degrees C/min to obtain almost fully crystalline HA powders. The heat-treated particles were characterized and introduced into a commercial glass ionomer cement. 4 (H4), 12 (H12) and 28 (H28) vol% of fluoroalumino silicate were substituted by crystalline HA particles that were dispersed using a high-speed dispersion technique. The HAIonomer cements were subjected to hardness, compressive and diametral tensile strength testing based upon BS6039:1981. The storage time were extended to one week to investigate the effects of cement maturation on mechanical properties. Commercially available capsulated GIC (GC) and GIC at maximum powder:liquid ratio (GM) served as comparisons. Results were analyzed using factorial ANOVA/Scheffe's post-hoc tests and independent samples t-test at significance level 0.05. The effect of time on hardness was material dependent. With the exception of H12, a significant increase in hardness was observed for all materials at one week. A significant increase in compressive strength was, however, observed for H12 over time. At 1 day and 1 week, the hardness of H28 was significantly lower than for GM, H4, and H12. No significant difference in compression and diametral tensile strengths were observed between materials at both time intervals. Results show that HAIonomers is a promising material, which possess good mechanical properties. Potential uses of this new material include bone cements and performed implants for hard tissue replacement in the field of otological, oral-maxillofacial and orthopedic surgery.

Effects of different CMV-heat-inactivation-methods on growth factors in human breast milk.

PubMed

Goelz, Rangmar; Hihn, Eva; Hamprecht, Klaus; Dietz, Klaus; Jahn, Gerhard; Poets, Christian; Elmlinger, Martin

2009-04-01

Preterm infants can inoculate virulent cytomegalovirus (CMV) through their mothers' raw breast milk. Complete virus inactivation is achieved only by heat treatment, but the effect on growth factors has never been assessed systematically. Insulin-like-growth-factor-1-, IGF-2-, insulin-like-growth-factor-binding-protein-2-, and IGFBP-3-concentrations were measured, before and after heating, in 51 breast-milk-samples from 28 mothers, and epidermal-growth-factor-concentrations in a subgroup of 35 samples from 22 mothers. Two heating methods were applied: Short-term (5 s) pasteurisation at 62, 65, and 72 degrees C, and long-term Holder-Pasteurisation (30 min) at 63 degrees C. IGF-1, IGF-2, IGFBP-2, and IGFBP-3 were measured by RIA, and EGF by ELISA. Heating for 30 min decreased significantly IGF-1 by 39.4%, IGF-2 by 9.9%, IGFBP-2 by 19.1%, and IGFBP-3 by 7.0%. In contrast, IGF-1, IGF-2, IGFBP-2, and IGFBP-3 were not altered significantly when using a short heating duration of 5 s, irrespective of the level of temperature, except for IGF-2 at 62 degrees C for 5 s (p = 0.041) and IGFBP-2 at 72 degrees C for 5 s (p = 0.025). Neither long- nor short-time heating methods changed the concentration of EGF. Only short heating methods (5 s, 62-72 degrees C) can preserve, almost completely, the concentrations of IGFs in human milk, whereas Holder-Pasteurization does not.

Heating of metallic implants and instruments induced by gradient switching in a 1.5-Tesla whole-body unit.

PubMed

Graf, Hansjörg; Steidle, Günter; Schick, Fritz

2007-11-01

To examine gradient switching-induced heating of metallic parts. Copper and titanium frames and sheets ( approximately 50 x 50 mm(2), 1.5 mm thick, frame width = 3 mm) surrounded by air were positioned in the scanner perpendicular to the static field horizontally 20 cm off-center. During the execution of a sequence (three-dimensional [3D] true fast imaging with steady precession [True-FISP], TR = 6.4 msec) exploiting the gradient capabilities (maximum gradient = 40 mT/m, maximum slew rate = 200 T/m/second), heating was measured with an infrared camera. Radio frequency (RF) amplitude was set to zero volts. Heating of a copper frame with a narrowing to 1 mm over 20 mm at one side was examined in air and in addition surrounded by several liters of gelled saline using fiber-optic thermography. Further heating studies were performed using an artificial hip made of titanium, and an aluminum replica of the hip prosthesis with the same geometry. For the copper specimens, considerable heating (>10 degrees C) in air and in gelled saline (>1.2 degrees C) could be observed. Heating of the titanium specimens was markedly less ( approximately 1 degrees C in air). For the titanium artificial hip no heating could be detected, while the rise in temperature for the aluminum replica was approximately 2.2 degrees C. Heating of more than 10 degrees C solely due to gradient switching without any RF irradiation was demonstrated in isolated copper wire frames. Under specific conditions (high gradient duty cycle, metallic loop of sufficient inductance and low resistance, power matching) gradient switching-induced heating of conductive specimens must be considered.

A capital cost comparison of commercial ground-source heat pump systems

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

Rafferty, K.

1994-06-01

The purpose of the report is to compare capital costs associated with the three designs of ground source heat pumps. Specifically, the costs considered are those associated with the heat source/heat sink or ground source portion of the system. In order to standardize the heat rejection over the three designs, it was assumed that the heat pump loop would operate at a temperature range of 85{degree} (to the heat pumps) to 95{degree} (from the heat pumps) under peak conditions. The assumption of constant loop temperature conditions for all three permits an apples-to-apples comparison of the alternatives.

Differential regulation by heat stress of novel cytochrome P450 genes from the dinoflagellate symbionts of reef-building corals.

PubMed

Rosic, Nedeljka N; Pernice, Mathieu; Dunn, Simon; Dove, Sophie; Hoegh-Guldberg, Ove

2010-05-01

Exposure to heat stress has been recognized as one of the major factors leading to the breakdown of the coral-alga symbiosis and coral bleaching. Here, we describe the presence of three new cytochrome P450 (CYP) genes from the reef-building coral endosymbiont Symbiodinium (type C3) and changes in their expression during exposure to severe and moderate heat stress conditions. Sequence analysis of the CYP C-terminal region and two conserved domains, the "PERF" and "heme-binding" domains, confirmed the separate identities of the CYP genes analyzed. In order to explore the effects of different heat stress scenarios, samples of the scleractinian coral Acropora millepora were exposed to elevated temperatures incrementally over an 18-h period (rapid thermal stress) and over a 120-h period (gradual thermal stress). After 18 h of gradual heating and incubation at 26 degrees C, the Symbiodinium CYP mRNA pool was approximately 30% larger, while a further 6 degrees C increase to a temperature above the average sea temperature (29 degrees C after 72 h) resulted in a 2- to 4-fold increase in CYP expression. Both rapid heat stress and gradual heat stress at 32 degrees C resulted in 50% to 90% decreases in CYP gene transcript abundance. Consequently, the initial upregulation of expression of CYP genes at moderately elevated temperatures (26 degrees C and 29 degrees C) was followed by a decrease in expression under the greater thermal stress conditions at 32 degrees C. These findings indicate that in the coral-alga symbiosis under heat stress conditions there is production of chemical stressors and/or transcriptional factors that regulate the expression of genes, such as the genes encoding cytochrome P450 monooxygenases, that are involved in the first line of an organism's chemical defense.

Effect of shift in growth temperature on tolerance of psychrotrophic and mesophilic strains of Bacillus cereus to heat and sodium chloride.

PubMed

Mahakarnchanakul, W; Beuchat, L R

1999-01-01

A shift in growth temperature of a psychrotrophic (F3802A/84) strain and a mesophilic strain (B4ac-1) of Bacillus cereus grown at 30 degrees C for 10 h, then at 37 degrees C or 40 degrees C for 14 h, enhanced thermotolerance. Sodium chloride, at concentrations of 2.0 and 4.0% in brain heart infusion (BHI) broth, had no effect on thermotolerance of strain B4ac-1 heated at 50 degrees C, whereas the same concentrations of NaCl caused a decrease in thermotolerance of strain F3802A/84 heated at 48 degrees C. A downshift in growth temperature from 30 degrees C to 10 degrees C followed by incubation for 3 to 9 days increased thermotolerance of strain F3802A/84 but not strain B4ac-1 heated in BHI broth containing 2.0 or 4.0% NaCl compared to thermotolerance in BHI broth containing 0.5% NaCl. Protein analysis using one-dimensional gel electrophoresis revealed an increase in proteins with molecular weights of 54, 50, 44, and 42 kDa in cells of strain F3802A/84 and 83 and 69 kDa in cells of strain B4ac-1 subjected to an upshift in growth temperature from 30 degrees C to 37 degrees C or 40 degrees C, respectively. A downshift in growth temperature from 30 degrees C to 10 degrees C resulted in substantial amounts of proteins with molecular weights of 63, 40, and 29 kDa produced by strain F3802A/84 and 63 kDa to be produced by strain B4ac-1. Proteins produced in response to upshift or downshift in growth temperature are suspected to play an important role in heat resistance of the psychrotrophic and mesophilic strains of B. cereus examined in this study. Changes in resistance to heat or refrigeration temperatures, as well as tolerance to NaCl, as affected by previous exposure of cells to temperature shifts may influence the ability of B. cereus to grow in minimally processed foods during distribution and storage.

Continuous passive motion with accelerated flexion after total knee arthroplasty.

PubMed

Yashar, A A; Venn-Watson, E; Welsh, T; Colwell, C W; Lotke, P

1997-12-01

The use of continuous passive motion after total knee arthroplasty remains controversial. A new approach, starting continuous passive motion at 70 degrees to 100 degrees flexion in the recovery room (Group I) was evaluated. A randomized, prospective study of 210 consecutive total knee arthroplasties was performed at two institutions. The control population (Group II) started continuous passive motion at 0 degree to 30 degrees, and progressed toward 100 degrees flexion. Flexion at postoperative Day 3 (Group I = 82.5 degrees, Group II = 72.8 degrees), and at discharge (Group I = 89.1 degrees, Group II = 84.3 degrees) were significantly different. There was no significant difference between the groups at 4 weeks (Group I = 5.0 degrees-104.1 degrees, Group II = 5.6 degrees-102.0 degrees), 6 weeks (Group I = 2.3 degrees-104.8 degrees, Group II = 2.7 degrees-103.6 degrees), 12 weeks (Group I = 1.7 degrees-107.7 degrees, Group II = 4.7 degrees-108.2 degrees), or at 1 year (Group I = 0.5 degree-113.2 degrees, Group II = 1.8 degrees-110.5 degrees). In Group I, wound necrosis developed in one patient that required a gastrocnemius flap. This major complication was caused by a tight dressing, and not necessarily to the accelerated flexion continuous passive motion. This investigation shows that continuous passive motion using accelerated flexion allows increased flexion during the hospital stay without increased risk of complications, pain, or blood loss. This has significant implications for achieving safe, early discharge. However, no difference was found at followup of 4 weeks or greater, and this did not add significantly to the final outcome.

Heat Exchanger Lab for Chemical Engineering Undergraduates

ERIC Educational Resources Information Center

Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.

2015-01-01

Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

The effect of heat transfer mode on heart rate responses and hysteresis during heating and cooling in the estuarine crocodile Crocodylus porosus.

PubMed

Franklin, Craig E; Seebacher, Frank

2003-04-01

The effect of heating and cooling on heart rate in the estuarine crocodile Crocodylus porosus was studied in response to different heat transfer mechanisms and heat loads. Three heating treatments were investigated. C. porosus were: (1) exposed to a radiant heat source under dry conditions; (2) heated via radiant energy while half-submerged in flowing water at 23 degrees C and (3) heated via convective transfer by increasing water temperature from 23 degrees C to 35 degrees C. Cooling was achieved in all treatments by removing the heat source and with C. porosus half-submerged in flowing water at 23 degrees C. In all treatments, the heart rate of C. porosus increased markedly in response to heating and decreased rapidly with the removal of the heat source. Heart rate during heating was significantly faster than during cooling at any given body temperature, i.e. there was a significant heart rate hysteresis. There were two identifiable responses to heating and cooling. During the initial stages of applying or removing the heat source, there was a dramatic increase or decrease in heart rate ('rapid response'), respectively, indicating a possible cardiac reflex. This rapid change in heart rate with only a small change or no change in body temperature (<0.5 degrees C) resulted in Q(10) values greater than 4000, calling into question the usefulness of this measure on heart rate during the initial stages of heating and cooling. In the later phases of heating and cooling, heart rate changed with body temperature, with Q(10) values of 2-3. The magnitude of the heart rate response differed between treatments, with radiant heating during submergence eliciting the smallest response. The heart rate of C. porosus outside of the 'rapid response' periods was found to be a function of the heat load experienced at the animal surface, as well as on the mode of heat transfer. Heart rate increased or decreased rapidly when C. porosus experienced large positive (above 25 W) or negative (below -15 W) heat loads, respectively, in all treatments. For heat loads between -15 W and 20 W, the increase in heart rate was smaller for the 'unnatural' heating by convection in water compared with either treatment using radiant heating. Our data indicate that changes in heart rate constitute a thermoregulatory mechanism that is modulated in response to the thermal environment occupied by the animal, but that heart rate during heating and cooling is, in part, controlled independently of body temperature.

Effect of thermal treatment on the quality of cloudy apple juice.

PubMed

Krapfenbauer, Gottfried; Kinner, Mathias; Gössinger, Manfred; Schönlechner, Regine; Berghofer, Emmerich

2006-07-26

Apple juice from eight different varieties of apples was heated at high-temperature (60-90 degrees C) and short-time (20-100 s) (HTST) combinations. To determine the effect of heating conditions on enzymatic browning and cloud stability in apple juices, the activity of polyphenol oxidase and pectinesterase was analyzed and correlated with the thermal treatment conditions and the quality of the juice. Additional investigations included the measurement of pH value, soluble solid content, titratable acidity, color, and turbidity after 3 and 6 months. The results showed that HTST treatment at 80 degrees C already inactivated polyphenol oxidase, whereas pectinesterase activity was reduced to half and could even at 90 degrees C not be inactivated completely. In fact, highest residual pectinesterase activity was found at 60 degrees C. Heating at 70 degrees C caused stable pectinesterase activity and even a slight increase for 50 and 100 s heating times. Turbidity and lightness increased after HTST treatment. In particular, differences in cloud stability between the varieties were measured. HTST parameters did not correlate with the residual cloud stability after 6 months. The sensory evaluation revealed that only a few combinations were distinguishable. The best stability of cloud and color in relation to heat impact was achieved by HTST treatment between 70 degrees C/100 s and 80 degrees C/20 s.

Balancing photosynthetic light-harvesting and light-utilization capacities in potato leaf tissue during acclimation to different growth temperatures

NASA Technical Reports Server (NTRS)

Steffen, K. L.; Wheeler, R. M.; Arora, R.; Palta, J. P.; Tibbitts, T. W.

1995-01-01

We investigated the effect of temperature during growth and development on the relationship between light-harvesting capacity, indicated by chlorophyll concentration, and light-utilization potential, indicated by light- and bicarbonate-saturated photosynthetic oxygen evolution, in Solanum tuberosum L. cv. Norland. Clonal plantlets were transplanted and grown at 20 degrees C for 2 weeks before transfer to 12, 16, 20, 24 and 28 degrees C for 6 weeks. After 4 weeks of the temperature treatments, leaf tissue fresh weights per area were one-third higher in plants grown at 12 degrees C vs those grown at 28 degrees C. Conversely, chlorophyll content per area in tissue grown at 12 degrees C was less than one-half of that of tissue grown at 28 degrees C at 4 weeks. Photosynthetic capacity measured at a common temperature of 20 degrees C and expressed on a chlorophyll basis was inversely proportional to growth temperature. Leaf tissue from plants grown at 12 degrees C for 4 weeks had photosynthetic rates that were 3-fold higher on a chlorophyll basis than comparable tissue from plants grown at 28 degrees C. These results suggest that the relationship between light-harvesting capacity and light-utilization potential varies 3-fold in response to the growth temperatures examined. The role of this response in avoidance of photoinhibition is discussed.

Effect of heating strategies on whey protein denaturation--Revisited by liquid chromatography quadrupole time-of-flight mass spectrometry.

PubMed

Akkerman, M; Rauh, V M; Christensen, M; Johansen, L B; Hammershøj, M; Larsen, L B

2016-01-01

Previous standards in the area of effect of heat treatment processes on milk protein denaturation were based primarily on laboratory-scale analysis and determination of denaturation degrees by, for example, electrophoresis. In this study, whey protein denaturation was revisited by pilot-scale heating strategies and liquid chromatography quadrupole time-of-flight mass spectrometer (LC/MC Q-TOF) analysis. Skim milk was heat treated by the use of 3 heating strategies, namely plate heat exchanger (PHE), tubular heat exchanger (THE), and direct steam injection (DSI), under various heating temperatures (T) and holding times. The effect of heating strategy on the degree of denaturation of β-lactoglobulin and α-lactalbumin was determined using LC/MC Q-TOF of pH 4.5-soluble whey proteins. Furthermore, effect of heating strategy on the rennet-induced coagulation properties was studied by oscillatory rheometry. In addition, rennet-induced coagulation of heat-treated micellar casein concentrate subjected to PHE was studied. For skim milk, the whey protein denaturation increased significantly as T and holding time increased, regardless of heating method. High denaturation degrees were obtained for T >100°C using PHE and THE, whereas DSI resulted in significantly lower denaturation degrees, compared with PHE and THE. Rennet coagulation properties were impaired by increased T and holding time regardless of heating method, although DSI resulted in less impairment compared with PHE and THE. No significant difference was found between THE and PHE for effect on rennet coagulation time, whereas the curd firming rate was significantly larger for THE compared with PHE. Micellar casein concentrate possessed improved rennet coagulation properties compared with skim milk receiving equal heat treatment. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Thermosensitive liposomes: extravasation and release of contents in tumor microvascular networks.

PubMed

Gaber, M H; Wu, N Z; Hong, K; Huang, S K; Dewhirst, M W; Papahadjopoulos, D

1996-12-01

The purpose of this study was to determine whether hyperthermic exposure would accelerate drug release from thermosensitive sterically stabilized liposomes and enhance their extravasation in tumor tissues. In vivo fluorescence video microscopy was used to measure the extravasation of liposomes, as well as release of their contents, in a rat skin flap window chamber containing a vascularized mammary adenocarcinoma under defined thermal conditions (34 degrees, 42 degrees, and 45 degrees C). Images of tissue areas containing multiple blood vessels were recorded via a SIT camera immediately before, and for up to 2 h after i.v. injection of two liposome populations with identical lipid composition: one liposome preparation was surface labeled with Rhodamine-PE (Rh-PE) and the other contained either Doxorubicin (Dox) or calcein at self-quenching concentrations. The light intensity of the entire tissue area was measured at 34 degrees C (the physiological temperature of the skin) for 1 h, and at 42 degrees or 45 degrees C for a second hour. These measurements were then used to calculate the fluorescent light intensity arising from each tracer (liposome surface label and the released contents) inside the vessel and in the interstitial region. The calculated intensity of Rh-PE for the thermosensitive liposomes in the interstitial space (which represents the amount of extravasated liposomes) was low during the first hour, while temperature was maintained at 34 degrees C and increased to 47 times its level before heating, when the tumor was heated at 42 degrees or 45 degrees C for 1 h. The calculated intensity of the liposome contents (Dox) in the interstitial space was negligible at 34 degrees C, and increased by 38- and 76-fold, when the tumor was heated at 42 degrees and 45 degrees C for 1 h, respectively. Similar values were obtained when calcein was encapsulated in liposomes instead of Dox. A similar increase in liposome extravasation was seen with nonthermosensitive liposomes, but negligible release of Dox occurred when the window chamber was heated to 45 degrees C for 1 h. Extravasation of liposomes continued after heating was stopped, but content release stopped after removal of heat. Release of Dox from extravasated liposomes was also seen if heating was applied 24 h after liposome administration, but no further enhancement of liposome extravasation occurred in this case. Our data suggest that hyperthermia can be used to selectively enhance both the delivery and the rate of release of drugs from thermosensitive liposomes to targeted tissues.

Improving the environment for weaned piglets using polypropylene fabrics above the animals in cold periods.

PubMed

Dolz, Noé; Babot, Daniel; Álvarez-Rodríguez, Javier; Forcada, Fernando

2015-12-01

This study aimed at evaluating the use of polypropylene fabrics in weaned pig facilities (5-10 weeks of age) during the winter period to improve thermal environment and energy saving for heating. Two experiments were conducted to validate the effects of fabrics (F) compared to control (C) in three 2-week periods using natural ventilation (assay 1, 2013) and forced ventilation (assay 2, 2014). Air temperature was greater in F than in C compartments in both years, particularly during the first 2-week periods (2 °C of mean difference). Natural ventilation was not enough to maintain relative humidity levels below 70 % at the end of the postweaning period (9-10 weeks of age) in both groups (F and C), whereas forced ventilation allowed controlling daily mean relative humidity levels <60 %. About 12-26 % of the radiant heat was transmitted through the fabrics cover, depending on the wavelength. There were no differences on growth performance of piglets in the two compartments in both years. The use of polypropylene fabrics was associated with a significant electric energy saving for heating during the first (data available only in 2014) and second 2-week period in both years. In conclusion, polypropylene fabrics may be an interesting tool to provide optimal environmental conditions for weaned piglets in winter, especially during the two first weeks after weaning. Their transmittance properties allow trapping infrared emission produced by the piglets and heating, avoiding heat losses through the roof, and therefore saving heating energy.

Survival of Listeria monocytogenes in milk during high-temperature, short-time pasteurization.

PubMed Central

Doyle, M P; Glass, K A; Beery, J T; Garcia, G A; Pollard, D J; Schultz, R D

1987-01-01

Milk from cows inoculated with Listeria monocytogenes was pooled for 2 to 4 days and then heated at 71.7 to 73.9 degrees C for 16.4 s or at 76.4 to 77.8 degrees C for 15.4 s in a high-temperature, short-time plate heat exchanger pasteurization unit. L. monocytogenes was isolated from milk after heat treatment in six of nine pasteurization trials done at 71.7 to 73.9 degrees C and in none of three trials done at 76.4 to 77.8 degrees C. An average of 1.5 to 9.2 L. monocytogenes cells was seen in each milk polymorphonuclear leukocyte before heat treatment in 11 of 12 pasteurization trials. Noticeable degradation of leukocytes with intracellular listeria was detected in unpasteurized milk after 3 days of storage at 4 degrees C, and by 4 days of storage leukocytes had deteriorated to cellular debris, suggesting that holding unpasteurized milk refrigerated for 4 or more days would eliminate a protective effect leukocytes may provide for increasing heat resistance of L. monocytogenes. Results indicate that under the conditions of this study, L. monocytogenes can survive the minimum high-temperature, short-time treatment (71.7 degrees C, 15 s) required by the U.S. Food and Drug Administration for pasteurizing milk. Images PMID:3116926

Growth inhibition of heat-injured Enterococcus faecium by oligophosphates in a cured meat model.

PubMed

Houben, J H; Tjeerdsma-van Bokhoven, J L M

2004-12-01

Cells of two heat-resistant strains of Enterococcus faecium were heated and incubated in meat suspensions containing curing ingredients. The concentrations of the curing ingredients were those frequently used for pasteurized ham-type products, except that the concentrations of the oligophosphates (triphosphate and diphosphate) varied. Heating tests at 69 degrees C were performed with inoculated meat suspensions in heat-sealed plastic pouches. Numbers of bacteria were counted immediately after heating and in parallel series of heated pouches incubated at 37 degrees C. Plating was performed in Tryptone Dextrose Yeast Meat Peptonised Milk Agar (TDYMP); in TDYMP Agar to which the curing ingredients were added; and in TDYMP Agar to which the curing ingredients except oligophosphates were added. The inclusion of oligophosphates in the heating medium increased the heat-injury sustained by the E. faecium cells, and in combination with rather severe heat treatment even completely blocked the growth of surviving organisms in the meat suspension incubated at 37 degrees C. The presence of oligophosphates in the culture medium TDYMP Agar severely reduced the counts of freshly heated cells; however, this effect disappeared after repair and growth of the surviving organisms in the meat suspension.

Graphite having improved thermal stress resistance and method of preparation

DOEpatents

Kennedy, Charles R.

1980-01-01

An improved method for fabricating a graphite article comprises the steps of impregnating a coke article by first heating the coke article in contact with a thermoplastic pitch at a temperature within the range of 250.degree.-300.degree. C. at a pressure within the range of 200-2000 psig for at least 4-10 hours and then heating said article at a temperature within the range of 450.degree.-485.degree. C. at a pressure of 200-2000 psig for about 16-24 hours to provide an impregnated article; heating the impregnated article for sufficient time to carbonize the impregnant to provide a second coke article, and graphitizing the second coke article. A graphite having improved thermal stress resistance results when the coke to be impregnated contains 1-3 wt.% sulfur and no added puffing inhibitors. An additional improvement in thermal stress resistance is achieved when the second coke article is heated above about 1400.degree. C. at a rate of at least 10.degree. C./minute to a temperature above the puffing temperature.

[MSW incineration fly ash melting by DSC-DTA].

PubMed

Li, Rundong; Chi, Yong; Li, Shuiqing; Wang, Lei; Yan, Jianhua; Cen, Kefa

2002-07-01

Melting characteristics of two kinds of municipal solid waste incineration(MSWI) fly ash were studied in this paper by high temperature differential scanning calorimetry and differential temperature analysis. MSWI fly ash was considered as hazardous waste because it contains heavy metals and dioxins. The experiments were performed in either N2 or O2 atmosphere in temperature range of 20 degrees C-1450 degrees C at various heating rates. Two different MSW incineration fly ashes used in the experiments were collected from our country and France respectively. The process of fly ash melting exhibits two reactions occurring at temperature ranges of about 480 degrees C-670 degrees C and 1136 degrees C-1231 degrees C, respectively. The latent heat of polymorphic transformation and fusion were approximately 20 kJ/kg and 700 kJ/kg, while the total heat required for melting process was about 1800 kJ/kg. The paper also studied effect of CaO to melting. A heat flux thermodynamic model for fly ash melting was put forward and it agrees well with experimental data.

Optimizing Mouse Surgery with Online Rectal Temperature Monitoring and Preoperative Heat Supply. Effects on Post-Ischemic Acute Kidney Injury.

PubMed

Marschner, Julian A; Schäfer, Hannah; Holderied, Alexander; Anders, Hans-Joachim

2016-01-01

Body temperature affects outcomes of tissue injury. We hypothesized that online body core temperature recording and selective interventions help to standardize peri-interventional temperature control and the reliability of outcomes in experimental renal ischemia reperfusion injury (IRI). We recorded core temperature in up to seven mice in parallel using a Thermes USB recorder and ret-3-iso rectal probes with three different protocols. Setup A: Heating pad during ischemia time; Setup B: Heating pad from incision to wound closure; Setup C: A ventilated heating chamber before surgery and during ischemia time with surgeries performed on a heating pad. Temperature profile recording displayed significant declines upon installing anesthesia. The profile of the baseline experimental setup A revealed that <1% of the temperature readings were within the target range of 36.5 to 38.5°C. Setup B and C increased the target range readings to 34.6 ± 28.0% and 99.3 ± 1.5%, respectively. Setup C significantly increased S3 tubular necrosis, neutrophil influx, and mRNA expression of kidney injury markers. In addition, using setup C different ischemia times generated a linear correlation with acute tubular necrosis parameters at a low variability, which further correlated with the degree of kidney atrophy 5 weeks after surgery. Changing temperature control setup A to C was equivalent to 10 minutes more ischemia time. We conclude that body temperature drops quickly in mice upon initiating anesthesia. Immediate heat supply, e.g. in a ventilated heating chamber, and online core temperature monitoring can help to standardize and optimize experimental outcomes.

Process for stabilizing dimensions of duplex stainless steels for service at elevated temperatures

DOEpatents

Hull, Frederick C.; Tobin, John C.

1981-01-01

Duplex stainless steel materials containing austenite plus delta ferrite, are dimensionally stabilized by heating the material to a reaction temperature between about 1050.degree.-1450.degree. F. (566.degree.-788.degree. C.), holding it at this temperature during transformation of delta ferrite to austenite plus sigma phase, and subsequently heating to a reversion temperature between about 1625.degree.-1750.degree. F. (885.degree.-954.degree. C.), whereby the sigma phase transforms back to ferrite, but the austenite remains dispersed in the ferrite phase. Final controlled cooling permits transformation of ferrite to austenite plus sigma and, later, precipitation of carbides.

Effects of semen preservation on boar spermatozoa head membranes.

PubMed

Buhr, M M; Canvin, A T; Bailey, J L

1989-08-01

Head plasma membranes were isolated from the sperm-rich fraction of boar semen and from sperm-rich semen that had been subjected to three commercial preservation processes: Extended for fresh insemination (extended), prepared for freezing but not frozen (cooled), and stored frozen for 3-5 weeks (frozen-thawed). Fluorescence polarization was used to determine fluidity of the membranes of all samples for 160 min at 25 degrees C and also for membranes from the sperm-rich and extended semen during cooling and reheating (25 to 5 to 40 degrees C, 0.4 degrees C/min). Head plasma membranes from extended semen were initially more fluid than from other sources (P less than 0.05). Fluidity of head membranes from all sources decreased at 25 degrees C, but the rate of decrease was significantly lower for membranes from cooled and lower again for membranes from frozen-thawed semen. Cooling to 5 degrees C reduced the rate of fluidity change for plasma membranes from the sperm-rich fraction, while heating over 30 degrees C caused a significantly greater decrease. The presence of Ca++ (10 mM) lowered the fluidity of the head plasma membranes from sperm-rich and extended semen over time at 25 degrees C but did not affect the membranes from the cooled or frozen-thawed semen. The change in head plasma membrane fluidity at 25 degrees C may reflect the dynamic nature of spermatozoa membranes prior to fertilization. Extenders, preservation processes and temperature changes have a strong influence on head plasma membrane fluidity and therefore the molecular organization of this membrane.

Cook/chill foodservice system with a microwave oven: aerobic plate counts from beef loaf, potatoes and frozen green beans.

PubMed

Dahl, C A; Matthews, M E; Marth, E H

1980-06-01

The purpose was to evaluate microbiological quality and end temperature (ET) of portioned food after heating in a microwave oven as used in a hospital cook/chill foodservice system. Beef loaf (15 kg), potatoes (6 kg), and green beans (5 kg) were prepared in a laboratory. After initial cooking to 60 degrees C, and storage (7 degrees C for 24 h), beef loaf (100 g) was microwave heated: 20, 50, 80 or 110 s. Potatoes were reconstituted, stored (7 degrees C for 24 h), portioned (100 g/portion), and microwave-heated: 25, 45, 65 or 84 s. Beans were thawed (7 degrees C for 24 h), portioned (100 g/portion), and microwave-heated: 20, 50, 80 or 110 s. Aerobic plate counts (APC) for foods were obtained throughout product flow. Wide ranges of Et and of APC in foods indicates that research is needed, for greater control of microwave-heating through advanced microwave engineering and food technology, to produce food with constant microbiological quality.

[Heat island effect and human body comfortable degree in Zhengzhou city].

PubMed

Zheng, Jinggang; Zhang, Jingguang; Li, You

2005-10-01

In this paper, the key factors of heat island effect in Zhengzhou city were monitored by grid method to study the diurnal and seasonal changes and the spatial distribution of the effect, and to evaluate the comfortable degree of human bodies at different sites of the city. The results showed that on the whole, the heat island effect had a unimodal diurnal change, while its intensity was distinctly different among seasons, being decreased in order of winter > spring > autumn > summer. The spatial distribution of heat island center was significantly related to its nearby industrial heat resources. As for the comfortable degree of human bodies, the People's Park was the best site because of its arbor virescence, while in the Xiliu Lake Park with lawn as its main greening type, its capability of improving microclimate was weaker. The railway station square still had 16% frequency of most comfortable degree, because of its open space and better air fluidity.

Ceramic Solar Receiver

NASA Technical Reports Server (NTRS)

Robertson, C., Jr.

1984-01-01

Solar receiver uses ceramic honeycomb matrix to absorb heat from Sun and transfer it to working fluid at temperatures of 1,095 degrees and 1,650 degrees C. Drives gas turbine engine or provides heat for industrial processes.

Method for heat treating iron-nickel-chromium alloy

DOEpatents

Korenko, Michael K.

1980-01-01

A method for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a morphology of the gamma-double prime phase enveloping the gamma-prime phase, the alloy consisting essentially of about 40 to 50% nickel, 7.5 to 14% chromium, 1.5 to 4% niobium, 0.3 to 0.75% silicon, 1 to 3% titanium, 0.1 to 0.5% aluminum, 0.02 to 1% carbon, 0.002 to 0.0015% boron and the remain substantially all iron. To obtain optimal results, the alloy is cold-worked 20 to 60% followed by heating at 1050.degree. C. for 1/2 hour with an air-cool plus heating at 800.degree. C. for 2 hours with a furnace cool to 625.degree. C. The alloy is then held at 625.degree. C. for 12 hours, followed by an air-cool.

Transcriptional activation by heat and cold of a thiol protease gene in tomato. [Lycopersicon esculentum

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

Schaffer, M.A.; Fischer, R.L.

We previously determined that low temperature induces the accumulation in tomato (Lycopersicon esculentum) fruit of a cloned mRNA, designated C14, encoding a polypeptide related to thiol proteases. We now demonstrate that C14 mRNA accumulation is a response common to both high (40{degree}C) and low (4{degree}C) temperature stresses. Exposure of tomato fruit to 40{degree}C results in the accumulation of C14 mRNA, by 8 hours. This response is more rapid than that to 4{degree}C, but slower than the induction of many heat shock messages by 40{degree}C, and therefore unique. We have also studied the mechanism by which heat and cold exposure activatemore » C14 gene expression. Both high and low temperature regulate protease gene expression through transcriptional induction of a single C14 gene. A hypothesis for the function of C14 thiol protease gene expression in response to heat and cold is discussed.« less

Thermal Performance of ATLAS Laser Thermal Control System Demonstration Unit

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin; Patel, Deepak; Ottenstein, Laura

2013-01-01

The second Ice, Cloud, and Land Elevation Satellite mission currently planned by National Aeronautics and Space Administration will measure global ice topography and canopy height using the Advanced Topographic Laser Altimeter System {ATLAS). The ATLAS comprises two lasers; but only one will be used at a time. Each laser will generate between 125 watts and 250 watts of heat, and each laser has its own optimal operating temperature that must be maintained within plus or minus 1 degree Centigrade accuracy by the Laser Thermal Control System (LTCS) consisting of a constant conductance heat pipe (CCHP), a loop heat pipe (LHP) and a radiator. The heat generated by the laser is acquired by the CCHP and transferred to the LHP, which delivers the heat to the radiator for ultimate rejection. The radiator can be exposed to temperatures between minus 71 degrees Centigrade and minus 93 degrees Centigrade. The two lasers can have different operating temperatures varying between plus 15 degrees Centigrade and plus 30 degrees Centigrade, and their operating temperatures are not known while the LTCS is being designed and built. Major challenges of the LTCS include: 1) A single thermal control system must maintain the ATLAS at 15 degrees Centigrade with 250 watts heat load and minus 71 degrees Centigrade radiator sink temperature, and maintain the ATLAS at plus 30 degrees Centigrade with 125 watts heat load and minus 93 degrees Centigrade radiator sink temperature. Furthermore, the LTCS must be qualification tested to maintain the ATLAS between plus 10 degrees Centigrade and plus 35 degrees Centigrade. 2) The LTCS must be shut down to ensure that the ATLAS can be maintained above its lowest desirable temperature of minus 2 degrees Centigrade during the survival mode. No software control algorithm for LTCS can be activated during survival and only thermostats can be used. 3) The radiator must be kept above minus 65 degrees Centigrade to prevent ammonia from freezing using no more than 135 watts of heater power. 4) The LHP reservoir control heater power is limited to 15 watts with a 70 percent duty cycle. 5) The voltage of the power supply can vary between 26 volts direct current and 34 volts direct current during the spacecraft lifetime. A design analysis shows that a single LTCS can satisfy these requirements. However, shutdown of· the LHP is particularly challenging and the shutdown heater must be wired in series with two reservoir thermostats and two CCHP thermostats at different set points. An LTCS demonstration unit has been tested to verify these performance characteristics experimentally prior to proceeding to the final LTCS design and fabrication. Test results showed that the LHP shutdown scheme would be able to shut down the LHP as designed and the reservoir control heater can maintain the ATLAS mass simulator within the plus or minus 1 degrees Centigrade accuracy under various combinations of the heat load, sink temperature, and power supply voltage.

Effects of ultrasonic dental scaling on pulp vitality in dogs: an experimental study.

PubMed

Vérez-Fraguela, J L; Vives Vallés, M A; Ezquerra Calvo, L J

2000-06-01

We investigated whether dental pulpal damage is produced as a result of the application of an ultrasonic scaler commonly used in clinical veterinary dentistry. Using methods developed in preliminary studies, we examined six dogs. The radiographic thickness of the dentin and pulp cavity was measured. The ultrasonic scaler was applied to maxillary and mandibular premolar teeth for 30, 60, or 90 seconds, without the use of water as a coolant. The temperatures of the room, the pulp canal on untreated incisor teeth, the cheek, the gingival sulcus, and the dentin of the affected teeth were recorded using a probe with a thermistor attached to a resistivity meter and inserted in the dentin to a depth of 1 mm. Two weeks following scaling, the teeth were extracted for microscopic examination. In another dog serving as a control, the temperature of the dentin was increased to between 45 degrees C (113 degrees F) and 47 degrees C (117 degrees F) and the premolar teeth were removed for microscopic examination 15 days later. We concluded that the application of an uncooled ultrasonic scaler for 90 seconds did not increase the temperature of the dentin. However, damage comparable with acute pulpitis resulted as a consequence of the ultrasonic effect, similar to the effects produced by the 45-47 degrees C heat applied in the control animal.

Determination of water vapor transmission rate (WVTR) of HDPE bottles for pharmaceutical products.

PubMed

Chen, Yisheng; Li, Yanxia

2008-06-24

The objective of this study was to investigate the effects of experimental conditions for measuring the water vapor transmission rate (WVTR) of high-density polyethylene (HDPE) bottles using a steady-state sorption method. Bottles were filled with desiccant, closed with caps and heat induction sealed, and then stored in stability chambers at controlled temperature and relative humidity. Weight gain of the bottles was determined every 1 or 2 weeks until a linear weight gain profile was obtained. WVTR of the bottles was determined from the slope of the linear portion of the weight gain versus time profile. The effects of desiccants and temperature/humidity were studied. Results show that, with a sufficient amount of anhydrous calcium chloride in bottles, a negligibly low and sufficiently constant headspace humidity is maintained, and a steady-state permeation rate is achieved. For all 8 sizes of bottles used in this study, steady-state was achieved in 1 or 2 weeks after the experiment was started. This method provided reproducible WVTR data for HDPE bottles. Apparent moisture permeability of all 8 sizes of bottles was (2.3+/-0.3)x10(-7), (2.6+/-0.2)x10(-7), and (3.4+/-0.2)x10(-7)cm(2)/s at 25 degrees C, 30 degrees C, 40 degrees C, respectively. Moisture permeability determined from the current study was similar to data reported in the literature, indicating that the steady-state weight gain method can be used to obtain reliable WVTR of containers for pharmaceutical products.

Intervertebral disc adaptation to wedging deformation.

PubMed

Stokes, Ian A F; Aronsson, David D; Clark, Katherine C; Roemhildt, Maria L

2006-01-01

Although scoliosis includes wedge deformities of both vertebrae and discs, little is known about the causes of the discal changes, and whether they result from mechanical influences on growth and/or remodelling. An external apparatus attached to transvertebral pins applied compression and 15 degrees of angulation to each of two adjacent young rat caudal intervertebral discs for 5 weeks (four animals), or for 10 weeks (four animals). Each week, micro-CT scanning documented the in vivo discal wedging. After euthanasia, tail segments (three vertebrae and the 2 angulated discs) were excised and their flexibility was measured over a range of lateral bending. The angle of maximum flexibility was recorded. Then discs were fixed in situ (with the external apparatus in place) and sectioned for polarized light microscopy. The disc-wedging deformity averaged 15 degrees initially, it averaged 20 degrees after 5 weeks, and then reduced to 10 degrees (in 10 week animals). The lateral bending flexibility showed a distinct maximum at an average of 1.1 degrees from the in vivo position in the 5-week animals, indicating structural remodeling of the discs almost to the deformed geometry. The 10-week animals had maximum flexibility at 1.4 degrees from the in vivo position (no significant difference between 5 and 10-week animals.) Collagen crimp angles [Cassidy et al., Conn Tiss Res 1989, 23:75-88] were not significantly different between convex and concave sides, again suggesting that remodeling had occurred. In a mechanically induced scoliosis deformity in skeletally immature rats, the intervertebral discs underwent remodeling within 5 weeks. This indicates that this animal model is suitable for studying adaptive wedging changes in human scoliosis.

On board short-time high temperature heat treatment of ballast water: a field trial under operational conditions.

PubMed

Quilez-Badia, Gemma; McCollin, Tracy; Josefsen, Kjell D; Vourdachas, Anthony; Gill, Margaret E; Mesbahi, Ehsan; Frid, Chris L J

2008-01-01

A ballast water short-time high temperature heat treatment technique was applied on board a car-carrier during a voyage from Egypt to Belgium. Ballast water from three tanks was subjected for a few seconds to temperatures ranging from 55 degrees C to 80 degrees C. The water was heated using the vessel's heat exchanger steam and a second heat exchanger was used to pre-heat and cool down the water. The treatment was effective at causing mortality of bacteria, phytoplankton and zooplankton. The International Maritime Organization (IMO) standard was not agreed before this study was carried out, but comparing our results gives a broad indication that the IMO standard would have been met in some of the tests for the zooplankton, in all the tests for the phytoplankton; and probably on most occasions for the bacteria. Passing the water through the pump increased the kill rate but increasing the temperature above 55 degrees C did not improve the heat treatment's efficacy.

Heating affects the content and distribution profile of isoflavones in steamed black soybeans and black soybean koji.

PubMed

Huang, Ru-Yue; Chou, Cheng-Chun

2008-09-24

Steamed black soybeans and black soybean koji, a potentially functional food additive, were subjected to heating at 40-100 degrees C for 30 min. It was found that steamed black soybeans and black soybean koji after heating at 80 degrees C or higher generally showed reduced contents of malonylglucoside, acetylglucoside, and aglycone isoflavone and an increased content of beta-glucoside. A lower reduction in malonylglucoside and acetylglucoside isoflavone but greater reduction in aglycone content was noted in steamed black soybeans compared to black soybean koji after a similar heat treatment. After 30 min of heating at 100 degrees C, steamed black soybean retained ca. 90.3 and 83.8%, respectively, of its original malonylglucoside and acetylglucoside isoflavone, compared to lower residuals of 80.9 and 78.8%, respectively, for black soybean koji. In contrast, the heated black soybeans showed an aglycone residual of 68.0%, which is less than the 80.0% noted with the heated black soybean koji.

Mechanical degradation temperature of waste storage materials

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

Fink, M.C.; Meyer, M.L.

1993-05-13

Heat loading analysis of the Solid Waste Disposal Facility (SWDF) waste storage configurations show the containers may exceed 90{degrees}C without any radioactive decay heat contribution. Contamination containment is primarily controlled in TRU waste packaging by using multiple bag layers of polyvinyl chloride and polyethylene. Since literature values indicate that these thermoplastic materials can begin mechanical degradation at 66{degrees}C, there was concern that the containment layers could be breached by heating. To better define the mechanical degradation temperature limits for the materials, a series of heating tests were conducted over a fifteen and thirty minute time interval. Samples of a low-densitymore » polyethylene (LDPE) bag, a high-density polyethylene (HDPE) high efficiency particulate air filter (HEPA) container, PVC bag and sealing tape were heated in a convection oven to temperatures ranging from 90 to 185{degrees}C. The following temperature limits are recommended for each of the tested materials: (1) low-density polyethylene -- 110{degrees}C; (2) polyvinyl chloride -- 130{degrees}C; (3) high-density polyethylene -- 140{degrees}C; (4) sealing tape -- 140{degrees}C. Testing with LDPE and PVC at temperatures ranging from 110 to 130{degrees}C for 60 and 120 minutes also showed no observable differences between the samples exposed at 15 and 30 minute intervals. Although these observed temperature limits differ from the literature values, the trend of HDPE having a higher temperature than LDPE is consistent with the reference literature. Experimental observations indicate that the HDPE softens at elevated temperatures, but will retain its shape upon cooling. In SWDF storage practices, this might indicate some distortion of the waste container, but catastrophic failure of the liner due to elevated temperatures (<185{degrees}C) is not anticipated.« less

Global Warming Impacts on Heating and Cooling Degree-Days in the United States

NASA Astrophysics Data System (ADS)

Petri, Y.; Caldeira, K.

2014-12-01

Anthropogenic climate change is expected to significantly alter residential air conditioning and space heating requirements, which account for 41% of U.S. household energy expenditures. The degree-day method can be used for reliable estimation of weather related building energy consumption and costs, as well as outdoor climatic thermal comfort. Here, we use U.S. Climate Normals developed by NOAA based on weather station observations along with Climate Model Intercomparison Project phase 5 (CMIP5) multi-model ensemble simulations. We add the projected change in heating and cooling degree-days based on the climate models to the estimates based on the NOAA U.S. Climate Normals to project future heating and cooling degree-days. We find locations with the lowest and highest combined index of cooling (CDDs) and heating degree-days (HDDs) for the historical period (1981 - 2010) and future period (2080 - 2099) under the Representation Concentration Pathway 8.5 (RCP8.5) climate change scenario. Our results indicate that in both time frames and among the lower 48 states, coastal areas in the West and South California will have the smallest degree-day sum (CDD + HDD), and hence from a climatic perspective become the best candidates for residential real estate. The Rocky Mountains region in Wyoming, in addition to northern Minnesota and North Dakota, will have the greatest CDD + HDD. While global warming is projected to reduce the median heating and cooling demand (- 5%) at the end of the century, CDD + HDD will decrease in the North, with an opposite effect in the South. This work could be helpful in deciding where to live in the United States based on present and future thermal comfort, and could also provide a basis for estimates of changes in heating and cooling energy demand.

Thermal effects of whole head submersion in cold water on nonshivering humans.

PubMed

Pretorius, Thea; Bristow, Gerald K; Steinman, Alan M; Giesbrecht, Gordon G

2006-08-01

This study isolated the effect of whole head submersion in cold water, on surface heat loss and body core cooling, when the confounding effect of shivering heat production was pharmacologically eliminated. Eight healthy male subjects were studied in 17 degrees C water under four conditions: the body was either insulated or uninsulated, with the head either above the water or completely submersed in each body-insulation subcondition. Shivering was abolished with buspirone (30 mg) and meperidine (2.5 mg/kg), and subjects breathed compressed air throughout all trials. Over the first 30 min of immersion, exposure of the head increased core cooling both in the body-insulated conditions (head out: 0.47 +/- 0.2 degrees C, head in: 0.77 +/- 0.2 degrees C; P < 0.05) and the body-exposed conditions (head out: 0.84 +/- 0.2 degrees C and head in: 1.17 +/- 0.5 degrees C; P < 0.02). Submersion of the head (7% of the body surface area) in the body-exposed conditions increased total heat loss by only 10%. In both body-exposed and body-insulated conditions, head submersion increased core cooling rate much more (average of 42%) than it increased total heat loss. This may be explained by a redistribution of blood flow in response to stimulation of thermosensitive and/or trigeminal receptors in the scalp, neck and face, where a given amount of heat loss would have a greater cooling effect on a smaller perfused body mass. In 17 degrees C water, the head does not contribute relatively more than the rest of the body to surface heat loss; however, a cold-induced reduction of perfused body mass may allow this small increase in heat loss to cause a relatively larger cooling of the body core.

Nasal inflammation in sleep apnoea patients using CPAP and effect of heated humidification.

PubMed

Koutsourelakis, I; Vagiakis, E; Perraki, E; Karatza, M; Magkou, C; Kopaka, M; Roussos, C; Zakynthinos, S

2011-03-01

Nasal continuous positive airway pressure (CPAP) can cause undesirable nasal symptoms, such as congestion to obstructive sleep apnoea (OSA) patients, whose symptoms can be attenuated by the addition of heated humidification. However, neither the nature of nasal symptoms nor the effect of heated humidification on nasal pathophysiology and pathology are convincingly known. 20 patients with OSA on nasal CPAP who exhibited symptomatic nasal obstruction were randomised to receive either 3 weeks of CPAP treatment with heated humidification or 3 weeks of CPAP treatment with sham-heated humidification, followed by 3 weeks of the opposite treatment, respectively. Nasal symptom score, nasal resistance, nasal lavage interleukin-6, interleukin-12 and tumour necrosis factor-α and nasal mucosa histopathology were assessed at baseline and after each treatment arm. Heated humidification in comparison with sham-heated humidification was associated with decrease in nasal symptomatology, resistance and lavage cytokines, and attenuation of inflammatory cell infiltration and fibrosis of the nasal mucosa. In conclusion, nasal obstruction of OSA patients on CPAP treatment is inflammatory in origin and the addition of heated humidification decreases nasal resistance and mucosal inflammation.

Cutaneous heat flow during heating and cooling in Alligator mississipiensis.

PubMed

Smith, E N

1976-05-01

Direct in vivo measurement of heat flow across the skin of the American alligator (Alligator mississipiensis) showed increased heat flow during warming. Mean values at 25 degrees C during warming (15-35 degrees C) in air (airspeed 300 cm/s) were 17.9 +/- 92 SE cal/cm2 per h (mean alligator wt 3.27 kg). Cooling heat flow at the same temperature was 13.6 +/- 0.57 cal/cm2 per h. Subdermal heat flow was reduced during warming and was not significantly different from cutaneous heat flow during cooling. This indicated that the alligator was able to control its rate of heat exchange with the environment by altering cutaneous perfusion. Atropine, phenoxybenzamine, nitroglycerin, and Xylocaine did not affect cutaneous heat flow or heating and cooling rates. Atropine blocked bradycardia during cooling.

A single, mild, transient scrotal heat stress causes DNA damage, subfertility and impairs formation of blastocysts in mice.

PubMed

Paul, Catriona; Murray, Alison A; Spears, Norah; Saunders, Philippa T K

2008-07-01

Infertility represents a major clinical problem and 50% of cases are attributable to the male partner. Testicular function is temperature dependent, and in both man and mouse the position of the testes in the scrotum ensures that they are kept at between 2 and 8 degrees C below core body temperature. We used a mouse model to investigate the impact of a single, transient, mild, scrotal heat stress (38, 40 or 42 degrees C for 30 min) on testicular function, sperm DNA integrity and embryo survival. We detected temperature-dependent changes in testicular architecture, number of apoptotic cells and a significant reduction in testis weight 7 and 14 days after heat stress at 42 degrees C. We report for the first time that DNA strand breaks (gamma-H2AX-positive foci) were present in spermatocytes recovered from testes subjected to 40 or 42 degrees C. Fertility of heat-stressed males was tested 23-28 d after treatment (sperm at this time would have been spermatocytes at time of heating). Paternal heat stress at 42 degrees C resulted in reduced pregnancy rate, placental weight and litter size; pregnancies from the 40 degrees C group had increased resorptions at e14.5. Abnormalities in embryonic development were detected at e3.5 and in vitro fertilisation with sperm recovered 16 h or 23 d after scrotal stress at 42 degrees C revealed a block in development between the 4-cell and blastocyst stages. This study has provided evidence of temperature-dependent effects on germ cell DNA integrity and highlighted the importance of an intact paternal genome for normal embryo development.

Impact of preheating on the behavior of Listeria monocytogenes in a broth that mimics Camembert cheese composition.

PubMed

Helloin, E; Bouttefroy, A; Gay, M; Phan Thanh, L

2003-02-01

The effect of preheating on the survival of L. monocytogenes in Richard's broth, which mimics the composition of Camembert cheese composition, was examined. Experiments were carried out to reproduce contamination of cheese with environmental heat-stressed cells of L. monocytogenes surviving hot-cleaning procedures. Cells in mid-log phase were heated for 30 min at 56 degrees C before being inoculated into Richard's broth. The pHs and temperatures of Richard's broth were chosen to recreate the conditions of curd dripping (pH 5, 25 degrees C), of the beginning of cheese ripening (pH 5, 12 degrees C), and of the beginning (pH 5, 4 degrees C) and the end (pH 7, 4 degrees C) of cheese storage. Immediately after heat treatment, the viability loss was especially high for strain 306715, which exhibited only 0.6% +/- 0.2% survival, compared with 22% +/- 8.7% for strain EGD. The percentages of the surviving heated cells that were injured were 93% +/- 8% for strain 306715 and 98% +/- 3% for strain EGD. The destruction of the surviving L. monocytogenes cells was accelerated when they encountered the pH and temperature conditions of Camembert cheese during manufacturing, ripening, and cold storage (pH 5 at 25, 12, and 4 degrees C, respectively). The multiplication of the surviving heated cells was retarded under favorable growth conditions similar to those of storage by the distributor and the consumer (pH 7 at 4 and 12 degrees C, respectively).

Effect of furnace type and ceramming heat treatment conditions on the biaxial flexural strength of a canasite glass-ceramic.

PubMed

Johnson, A; Shareef, M Y; van Noort, R; Walsh, J M

2000-07-01

To assess the effect of different heat treatment conditions when using two different furnace types on the biaxial flexural strength (BFS) of a fluorcanasite castable glass-ceramic. Two furnace types, one a programmable furnace (PF), the other a dental laboratory burnout furnace (DLF), were used with various ceramming times to determine their effect on the BFS of a fluorcanasite castable glass-ceramic. The glass-ceramic material was cast to produce discs of 12 mm diameter and 2 mm thickness using the lost wax casting process (n = 80). After casting, both furnace types were used to ceram the discs. Half the discs were not de-vested from the casting ring before ceramming but cerammed in situ (DLF) and half were de-vested before ceramming (PF). All the discs were given a nucleation heat treatment at 520 degrees C for 1 h and then cerammed at 860 degrees C using four heat soak times (0.5, 1, 2 and 3 h). The DLF furnace had a rate of climb of 13 degrees C/min and the PF furnace had a rate of climb of 5 degrees C/min to 520 degrees C and 3 degrees C/min to 860 degrees C. After ceramming the discs were de-vested and the BFS determined using a Lloyd 2000R tester. The maximum BFS values seen for both furnace types were almost identical (280 MPa), but were achieved at different heat soak times (1 h DLF, and 2 h PF). The only significant differences in BFS values for the two furnaces were between the 0.5 and 2 h heat soak times (p < or = 0.05). Individual differences were seen between results obtained from each furnace type/heat soak times evaluated (p < or = 0.05). Already available dental laboratory burnout furnaces can be used to ceram fluorcanasite glass-ceramic castings to the same BFS values as more expensive and slower specialist programmable furnaces.

Inactivation of Escherichia coli in a tropical fruit smoothie by a combination of heat and pulsed electric fields.

PubMed

Walkling-Ribeiro, M; Noci, F; Cronin, D A; Lyng, J G; Morgan, D J

2008-10-01

Moderate heat in combination with pulsed electric fields (PEF) was investigated as a potential alternative to thermal pasteurization of a tropical fruit smoothie based on pineapple, banana, and coconut milk, inoculated with Escherichia coli K12. The smoothie was heated from 25 degrees C to either 45 or 55 degrees C over 60 s and subsequently cooled to 10 degrees C. PEF was applied at electric field strengths of 24 and 34 kV/cm with specific energy inputs of 350, 500, and 650 kJ/L. Both processing technologies were combined using heat (45 or 55 degrees C) and the most effective set of PEF conditions. Bacterial inactivation was estimated on standard and NaCl-supplemented tryptone soy agar (TSA) to enumerate sublethally injured cells. By increasing the temperature from 45 to 55 degrees C, a higher reduction in E. coli numbers (1 compared with 1.7 log(10) colony forming units {CFU} per milliliter, P < 0.05) was achieved. Similarly, as the field strength was increased during stand-alone PEF treatment from 24 to 34 kV/cm, a greater number of E. coli cells were inactivated (2.8 compared with 4.2 log(10) CFU/mL, P < 0.05). An increase in heating temperature from 45 to 55 degrees C during a combined heat/PEF hurdle approach induced a higher inactivation (5.1 compared with 6.9 log(10) CFU/mL, respectively [P < 0.05]) with the latter value comparable to the bacterial reduction of 6.3 log(10) CFU/mL (P> or = 0.05) achieved by thermal pasteurization (72 degrees C, 15 s). A reversed hurdle processing sequence did not affect bacterial inactivation (P> or = 0.05). No differences were observed (P> or = 0.05) between the bacterial counts estimated on nonselective and selective TSA, suggesting that sublethal cell injury did not occur during single PEF treatments or combined heat/PEF treatments.

Decontamination of drinking water by direct heating in solar panels.

PubMed

Fjendbo Jørgensen, A J; Nøhr, K; Sørensen, H; Boisen, F

1998-09-01

A device was developed for direct heating of water by solar radiation in a flow-through system of copper pipes. An adjustable thermostat valve prevents water below the chosen temperature from being withdrawn. The results show that it is possible to eliminate coliform and thermotolerant coliform bacteria from naturally contaminated river water by heating to temperatures of 65 degrees C or above. Artificial additions of Salmonella typhimurium, Streptococcus faecalis and Escherichia coli to contaminated river water were also inactivated after heating to 65 degrees C and above. The total viable count could be reduced by a factor of 1000. The heat-resistant bacteria isolated from the Mlalakuva River (Tanzania) were spore-forming bacteria which exhibited greater heat resistance than commonly used test bacteria originating from countries with colder climates. To provide a good safety margin it is recommended that an outlet water temperature of 75 degrees C be used. At that temperature the daily production was about 501 of decontaminated water per m2 of solar panel, an amount that could be doubled by using a heat exchanger to recycle the heat.

The effect of high indoor temperatures on self-perceived health of elderly persons.

PubMed

van Loenhout, J A F; le Grand, A; Duijm, F; Greven, F; Vink, N M; Hoek, G; Zuurbier, M

2016-04-01

Exposure to high ambient temperatures leads to an increase in mortality and morbidity, especially in the elderly. This relationship is usually assessed with outdoor temperature, even though the elderly spend most of their time indoors. Our study investigated the relationship between indoor temperature and heat-related health problems of elderly individuals. The study was conducted in the Netherlands between April and August 2012. Temperature and relative humidity were measured continuously in the living rooms and bedrooms of 113 elderly individuals. Respondents were asked to fill out an hourly diary during three weeks with high temperature and one cold reference week, and a questionnaire at the end of these weeks, on health problems that they experienced due to heat. During the warmest week of the study period (14-20 August), average living room and bedroom temperatures were approximately 5°C higher than during the reference week. More than half of the respondents perceived their indoor climate as too warm during this week. The most reported symptoms were thirst (42.7%), sleep disturbance (40.6%) and excessive sweating (39.6%). There was a significant relationship between both indoor and outdoor temperatures with the number of hours that heat-related health problems were reported per day. For an increase of 1°C of indoor temperature, annoyance due to heat and sleep disturbance increased with 33% and 24% respectively. Outdoor temperature was associated with smaller increases: 13% and 11% for annoyance due to heat and sleep disturbance, respectively. The relationship between outdoor temperature and heat-related health problems disappeared when indoor and outdoor temperatures were included in one model. The relationship with heat-related health problems in the elderly is stronger with indoor (living room and bedroom) temperature than with outdoor temperature. This should be taken into account when looking for measures to reduce heat exposure in this vulnerable group. Copyright © 2015 Elsevier Inc. All rights reserved.

Glove thermal insulation: local heat transfer measures and relevance.

PubMed

Sari, Hayet; Gartner, Maurice; Hoeft, Alain; Candas, Victor

2004-09-01

When exposed to cold, the hands need to be protected against heat loss not only in order to reduce thermal discomfort, but also to keep their efficiency. Although gloves are usually the most common protection, their thermal insulation is generally unknown. The aim of this study was to measure the heat losses from a gloved hand with a special interest in local variations. Using a calorimetric hand placed in a cold box, several types of gloves were tested. The results indicated that depending on the glove and on the area covered the heat loss reduction may vary from almost 60% to 90%. When the least efficient pair of gloves was excluded, heat exchange coefficients varied from 1.8 to 4.8 W/m2 per degrees C for the palm and from 4.2 to 6.2 W/m2 per degrees C for the back of the hand. The three medium fingers seemed to be equally treated, with a heat exchange coefficient variation of 6.3-9.0 W/m2 per degrees C. The thumb and the little finger, which require better insulation, exhibited higher local heat transfer coefficients of 8.3-12.7 W/m2 per degrees C. Some practical aspects are evoked.

Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas).

PubMed

Broderick, A C; Godley, B J; Hays, G C

2001-01-01

We compared incubation temperatures in nests (n=32) of the green turtle (Chelonia mydas) on Ascension Island in relation to sand temperatures of control sites at nest depth. Intrabeach thermal variation was low, whereas interbeach thermal variation was high in both control and nest sites. A marked rise in temperature was recorded in nests from 30% to 40% of the way through the incubation period and attributed to metabolic heating. Over the entire incubation period, metabolic heating accounted for a mean rise in temperature of between 0.07 degrees and 2.86 degrees C within nests. During the middle third of incubation, when sex is thought to be determined, this rise in temperature ranged between 0.07 degrees and 2.61 degrees C. Metabolic heating was related to both the number of eggs laid and the total number of hatchlings/embryos produced in a clutch. For 32 clutches in which temperature was recorded, we estimate that metabolic heating accounted for a rise of up to 30% in the proportion of females produced within different clutches. Previous studies have dismissed any effect of metabolic heating on the sex ratio of marine turtle hatchlings. Our results imply that metabolic heating needs to be considered when estimating green turtle hatchling sex ratios.

Glass ceramic toughened with tetragonal zirconia

DOEpatents

Keefer, Keith D.; Michalske, Terry A.

1986-01-01

A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat-treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nucleating agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200.degree. to 1700.degree. C. and is then heat-treated at a temperature within the range of 800.degree. to 1200.degree. C. in order to precipitate tetragonal ZrO.sub.2. The composition, as well as the length and temperature of the heat-treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.

Physiological effects of solar heat load in a fighter cockpit.

PubMed

Nunneley, S A; Myhre, L G

1976-09-01

The use of bubble canopies to improve vision in fighter aircraft exposes the cockpit to a high radiant heat load. Incoming sunlight increases the heat stress on crewmembers, both by raising air temperature and by directly heating exposed skin and clothing. An F-15 aircraft at Edwards AFB was modified to permit cockpit ventilation by external ground carts. Eight volunteers from the Test Pilot School were studied during 1-h periods in the closed cockpit, in sun and in shade. Mean cockpit air temperatures were 35.2 degrees C in shade and 51.9 degrees C in sun with PH2O less than 10 torr. The corresponding WBGT's were 22.6 and 36.4 degrees C. Sunlight added significantly to overall heat stress, as indicated by a rising heart rate and evaporative weight loss of 284 g/m2 - h (shade value was 109 g/m2 - hr). Mean skin temperatures were 34.3 degrees C in shade and 35.8 degrees C in sun. Particularly high skin temperatures were observed on the chest, the forehead and the top of the head under the helmet. The legs remained cool due to the flow of conditioned air, and this may explain why rectal temperature showed no meaningful change. Heat stress, which alone poses no physiological hazard, may cause crew performance decrements as well as diminishing acceleration tolerance. Possible means of eliminating or ameliorating these effects are discussed.

Experimental investigation of the effects of compound angle holes on film cooling effectiveness and heat transfer performance using a transient liquid crystal thermometry technique

NASA Astrophysics Data System (ADS)

Seager, David J.; Liburdy, James A.

1997-11-01

To further understand the effect of both compound angle holes and hole shaping on film cooling, detailed heat transfer measurements were obtained using hue based thermochromic liquid crystal method. The data were analyzed to measure both the full surface adiabatic effectiveness and heat transfer coefficient. The compound angles that were evaluated consist of holes that were aligned 0 degrees, 45 degrees, 60 degrees and 90 degrees to the main cross flow direction. Hole shaping variations from the traditional cylindrical shaped hole include forward diffused and laterally diffused hole geometries. Geometric parameters that were selected were the length to diameter ratio of 3.0, and the inclination angle 35 degrees. A density ratio of 1.55 was obtained for all teste. For each set of conditions the blowing ratio was varied to be 0.88, 1.25, and 1.88. Adiabatic effectiveness was obtained using a steady state test, while an active heating surface was used to determine the heat transfer coefficient using a transient method. The experimental method provides a unique method of analyzing a three-temperature heat transfer problem by providing detailed surface transport properties. Based on these results for the different hole geometries at each blowing ratio conclusions are drawn relative to the effects of compound angle holes on the overall film cooling performance.

Antigenicity and viability of Anisakis larvae infesting hake heated at different time-temperature conditions.

PubMed

Vidacek, Sanja; de las Heras, Cristina; Solas, Maria Teresa; Mendizábal, Angel; Rodriguez-Mahillo, Ana I; Tejada, Margarita

2010-01-01

Heat treatments (40 to 94 degrees Celsius, 30 s to 60 min) were applied to different batches of Anisakis simplex L3 larvae isolated from hake ovaries and viscera to study the effect of heat on the viability of the larvae measured as mobility, emission of fluorescence under UV light, and changes in color after staining with specific dyes, and on A. simplex antigenic proteins. The aim was to determine the lowest time-temperature conditions needed to kill the larvae to avoid anisakiasis in consumers, and to evaluate whether high temperature modifies the antigenicity of A. simplex extracts. Heating at 60 degrees Celsius for 10 min (recommended by some authors) was considered unsafe, as differences in viability between batches were found, with some larvae presenting spontaneous movements in one batch. At higher temperatures (> or = 70 degrees Celsius for > or = 1 min), no movement of the larvae was observed. Antigenic protein Ani s 4 and A. simplex crude antigens were detected in the larvae heated at 94 + or - 1 degrees Celsius for 3 min. This indicates that allergic symptoms could be provoked in previously sensitized consumers, even if the larvae were killed by heat treatment.

Thermal removal of pyrene contamination from soil: basic studies and environmental health implications.

PubMed Central

Saito, H H; Bucalá, V; Howard, J B; Peters, W A

1998-01-01

Effects of temperature (400-1000 degrees C) and rate of heating to 550 degrees C (100, 1000, 5000 degrees C/sec) on reduction of pyrene contamination in a Superfund-related soil and on yields of volatile products (tars, CO, CO2, methane, acetylene, ethylene) have been measured. Fifty (+/- 3)-milligram thin layers (less than or equal to 150 micron) of 63- to 125-micron soil particles, neat (i.e., without exogenous chemicals), or pretreated with 4.75 wt% of pyrene, were heated for about 1 to 6 sec, under 3 psig (pounds per in.(2) gauge) of helium in a 12-liter sealed chamber. Pyrene removal, defined as the difference in weight loss of neat versus contaminated soil, was virtually immune to heating rate but increased strongly with increasing temperature, approaching 100% at about 530 degrees C. However, for pyrenepolluted soil, excess soil weight loss and modified CO yields were observed above about 500 degrees C for a 1000 degrees C/sec heating rate. These observations suggest that soil chemical reactions with pyrene or pyrene decomposition products augment soil volatilization. Consequently at elevated temperatures, the difference in weight loss protocol may overestimate polycyclic aromatic hydrocarbon (PAH) removal from soil. Increasing heating rate caused yields of CO, CO(2), and acetylene from pyrene-polluted soil to pass through maxima. Heating neat or contaminated soil resulted in at least two gaseous products of particular environmental interest:acetylene, a precursor to PAH in thermal synthesis, and CO, a toxin to human hemoglobin. Images Figure 1 Figure 2 PMID:9703498

Application of conjugated heparin-albumin microparticles with laser-balloon angioplasty: a potential method for reducing adverse biologic reactivity after angioplasty

NASA Astrophysics Data System (ADS)

Kundu, Sourav K.; McMath, Linda P.; Zaidan, Jonathan T.; Spears, J. Richard

1991-05-01

Laser-balloon angioplasty (LBA) may potentially be used for local application of pharmacologically active agents which will reduce thrombogenic and proliferative responses after the angioplasty. In this study, the feasibility of applying covalently conjugated heparin- albumin microparticles onto arterial luminal surface was demonstrated. The covalent linkages were formed by reaction with 1-ethyl-3-dimethyl-aminopropyl-carbodiimide (EDC), and the resultant conjugates were used for preparation of microparticles by employing standard emulsification and heat-crosslinking techniques. The heparin release rate from the microparticles was found to be dependent upon the degree of crosslinking. When a thin coagulum of a suspension of microparticles was formed with heat on a glass surface, the treated surface demonstrated resistance to clot formation in contact with non-anticoagulated blood. A suspension of the microparticles applied during laser-balloon angioplasty onto the luminal surface of dog carotid and femoral arteries showed persistence for up to one week without thrombus formation or occlusion of the vessel. Since the rate of biodegradation is primarily dictated by the extent of crosslinking, an optimal degree of thermal denaturation will permit longer persistence of the carrier while allowing adequate release of the entrapped pharmacologic agent. A variety of antithrombotic and antiinflammatory agents are being considered as candidate bioprotective materials for local application after angioplasty.

A novel hsp110-related gene, apg-1, that is abundantly expressed in the testis responds to a low temperature heat shock rather than the traditional elevated temperatures.

PubMed

Kaneko, Y; Nishiyama, H; Nonoguchi, K; Higashitsuji, H; Kishishita, M; Fujita, J

1997-01-31

We isolated a novel hsp110-related gene, apg-1, from a testis cDNA library. The apg-1 transcripts were constitutively expressed in the testicular germ cells and, in some degree, most tissues examined. In a mouse TAMA26 Sertoli cell line, apg-1 transcripts were induced in 2 h by a temperature shift from 32 to 39 degrees C, but not by a shift from 37 to 42 degrees C, the traditional heat stress, or a shift from 32 to 42 degrees C. The heat response pattern of hsp110 expression was similar to that of apg-1. Although induction of a hsp70 transcript was observed in 2 h by a shift from 32 to 39 degrees C, the induction was more apparent by a shift from 37 to 42 degrees C or from 32 to 42 degrees C. Essentially similar differential response patterns were observed among these genes in NIH/3T3 fibroblasts as well. The nuclear run-on assay and the native gel mobility shift assay demonstrated that, by the 32 to 39 degrees C temperature shift, the apg-1 gene was transcriptionally activated, and heat shock factor 1 bound to the heat shock elements in the 5'-flanking region of the apg-1 gene. These results demonstrated that expressions of apg-1, hsp110, and hsp70 could be heat-induced at a temperature lower than the traditional elevated temperatures in somatic cells of both testis and nontestis origin and suggest that the mechanisms regulating the transcript levels of apg-1 and hsp110 are different from those of hsp70. Furthermore, the constitutive expression in germ cells suggests that APG-1 plays a specific role in spermatogenesis as well as in stress response.

Y-piece temperature and humidification during mechanical ventilation.

PubMed

Solomita, Mario; Daroowalla, Feroza; Leblanc, Deniese S; Smaldone, Gerald C

2009-04-01

Practitioners often presume there is adequate humidification in the ventilator circuit if the Y-piece is at a specified temperature, but control of Y-piece temperature may be inadequate to ensure adequate humidification. In an in vitro bench model we measured water-vapor delivery with several heated humidification setups and a wide range of minute volume (V (E)) values. The setup included a condenser, hygrometry, and thermometer. First, we calibrated the system with a point-source humidifier and water pump. Then we tested the water-vapor delivery during non-heated-wire humidification and during heated-wire humidification with a temperature gradient of +3 degrees C, 0 degrees C, and -3 degrees C between the humidifier and the Y-piece. We compared the results to 2 recommended humidification values: 100% saturated (absolute humidity 44 mg H(2)O/L) gas at 37 degrees C (saturated/37 degrees C); and 75% saturated (absolute humidity 33 mg H(2)O/L), which is the humidity recommended by the International Organization for Standardization (the ISO standard). In all the experiments the setup was set to provide 35 degrees C at the Y-piece. Our method for measuring water-vapor delivery closely approximated the amount delivered by a calibrated pump, but slightly underestimated the water-vapor delivery in all the experiments and the whole V (E) range. At all V (E) values, water-vapor delivery during non-heated-wire humidification matched or exceeded saturated/37 degrees C and was significantly greater than that during heated-wire humidification. During heated-wire humidification, water-vapor delivery varied with the temperature gradient and did not reach saturated/37 degrees C at V (E) > 6 L/min. Water-vapor delivery with the negative temperature gradient was below the ISO standard. Maintaining temperature at one point in the inspiratory circuit (eg, Y-piece), does not ensure adequate water-vapor delivery. Other factors (humidification system, V (E), gradient setting) are critical. At a given temperature, humidification may be significantly higher or lower than expected.

Objective correlate of subjective pain perception by contact heat-evoked potentials.

PubMed

Granovsky, Yelena; Granot, Michal; Nir, Rony-Reuven; Yarnitsky, David

2008-01-01

The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.

High environmental temperature and preterm birth: a review of the evidence.

PubMed

Carolan-Olah, Mary; Frankowska, Dorota

2014-01-01

to examine the evidence in relation to preterm birth and high environmental temperature. this review was conducted against a background of global warming and an escalation in the frequency and severity of hot weather together with a rising preterm birth rate. electronic health databases such as: SCOPUS, MEDLINE, CINAHL, EMBASE and Maternity and Infant Care were searched for research articles, that examined preterm birth and high environmental temperature. Further searches were based on the reference lists of located articles. Keywords included a search term for preterm birth (preterm birth, preterm, premature, <37 weeks, gestation) and a search term for hot weather (heatwaves, heat-waves, global warming, climate change, extreme heat, hot weather, high temperature, ambient temperature). A total of 159 papers were retrieved in this way. Of these publications, eight met inclusion criteria. data were extracted and organised under the following headings: study design; dataset and sample; gestational age and effect of environmental heat on preterm birth. Critical Appraisal Skills Programme (CASP) guidelines were used to appraise study quality. in this review, the weight of evidence supported an association between high environmental temperature and preterm birth. However, the degree of association varied considerably, and it is not clear what factors influence this relationship. Differing definitions of preterm birth may also add to lack of clarity. preterm birth is an increasingly common and debilitating condition that affects a substantial portion of infants. Rates appear to be linked to high environmental temperature, and more especially heat stress, which may be experienced during extreme heat or following a sudden rise in temperature. When this happens, the body may be unable to adapt quickly to the change. As global warming continues, the incidence of high environmental temperature and dramatic temperature changes are also increasing. This situation makes it important that research effort is directed to understanding the degree of association and the mechanism by which high temperature and temperature increases impact on preterm birth. Research is also warranted into the development of more effective cooling practices to ameliorate the effects of heat stress. In the meantime, it is important that pregnant women are advised to take special precautions to avoid heat stress and to keep cool when there are sudden increases in temperature. Copyright © 2013 Elsevier Ltd. All rights reserved.

Composite prepreg application device

NASA Technical Reports Server (NTRS)

Sandusky, Donald A. (Inventor); Marchello, Joseph M. (Inventor)

1996-01-01

A heated shoe and cooled pressure roller assembly for composite prepreg application is provided. The shoe assembly includes a heated forward contact surface having a curved pressure surface. The following cooled roller provides a continuous pressure to the thermoplastic while reducing the temperature to approximately 5.degree. C. below glass transition temperature. Electric heating coils inside the forward portion of the shoe heat a thermoplastic workpiece to approximately 100.degree. C. above the glass transition. Immediately following the heated contact surface, a cooled roller cools the work. The end sharpened shape of the heated shoe trailing edge tends to prevent slag buildup and maintain a uniform, relaxed stress fabrication.

Acoustic Levitator With Furnace And Laser Heating

NASA Technical Reports Server (NTRS)

Barmatz, Martin B.; Stoneburner, James D.

1991-01-01

Acoustic-levitation apparatus incorporates electrical-resistance furnace for uniform heating up to temperature of about 1,000 degrees C. Additional local heating by pair of laser beams raise temperature of sample to more than 1,500 degrees C. High temperature single-mode acoustic levitator generates cylindrical-mode accoustic resonance levitating sample. Levitation chamber enclosed in electrical-resistance furnace. Infrared beams from Nd:YAG laser provide additional local heating of sample. Designed for use in containerless processing of materials in microgravity or in normal Earth gravity.

INTRACORPOREAL HEAT DISSIPATION FROM A RADIOISOTOPE-POWERED ARTIFICIAL HEART.

PubMed

Huffman, Fred N.; Hagen, Kenneth G.; Whalen, Robert L.; Fuqua, John M.; Norman, John C.

1974-01-01

The feasibility of radioisotope-fueled circulatory support systems depends on the ability of the body to dissipate the reject heat from the power source driving the blood pump as well as to tolerate chronic intracorporeal radiation. Our studies have focused on the use of the circulating blood as a heat sink. Initial in vivo heat transfer studies utilized straight tube heat exchangers (electrically and radioisotope energized) to replace a segment of the descending aorta. More recent studies have used a left ventricular assist pump as a blood-cooled heat exchanger. This approach minimizes trauma, does not increase the area of prosthetic interface with the blood, and minimizes system volume. Heat rejected from the thermal engine (vapor or gas cycle) is transported from the nuclear power source in the abdomen to the pump in the thoracic cavity via hydraulic lines. Adjacent tissue is protected from the fuel capsule temperature (900 to 1200 degrees F) by vacuum foil insulation and polyurethane foam. The in vivo thermal management problems have been studied using a simulated thermal system (STS) which approximates the heat rejection and thermal transport mechanisms of the nuclear circulatory support systems under development by NHLI. Electric heaters simulate the reject heat from the thermal engines. These studies have been essential in establishing the location, suspension, surgical procedures, and postoperative care for implanting prototype nuclear heart assist systems in calves. The pump has a thermal impedance of 0.12 degrees C/watt. Analysis of the STS data in terms of an electrical analog model implies a heat transfer coefficient of 4.7 x 10(-3) watt/cm(2) degrees C in the abdomen compared to a value of 14.9 x 10(-3) watt/cm(2) degrees C from the heat exchanger plenum into the diaphragm.

Effect of heat treatment on the antioxidant activity of extracts from citrus peels.

PubMed

Jeong, Seok-Moon; Kim, So-Young; Kim, Dong-Ryul; Jo, Seong-Chun; Nam, K C; Ahn, D U; Lee, Seung-Cheol

2004-06-02

The effect of heat treatment on the antioxidant activity of extracts from Citrus unshiu peels was evaluated. Citrus peels (CP) (5 g) were placed in Pyrex Petri dishes (8.0 cm diameter) and heat-treated at 50, 100, or 150 degrees C for 10, 20, 30, 40, 50, and 60 min in an electric muffle furnace. After heat treatment, 70% ethanol extract (EE) and water extract (WE) (0.1 g/10 mL) of CP were prepared, and total phenol contents (TPC), radical scavenging activity (RSA), and reducing power of the extracts were determined. The antioxidant activities of CP extracts increased as heating temperature increased. For example, heat treatment of CP at 150 degrees C for 60 min increased the TPC, RSA, and reducing power of EE from 71.8 to 171.0 microM, from 29.64 to 64.25%, and from 0.45 to 0.82, respectively, compared to non-heat-treated control. In the case of WE from CP heat-treated at the same conditions (150 degrees C for 60 min), the TPC, RSA, and reducing power also increased from 84.4 to 204.9 microM, from 15.81 to 58.26%, and from 0.27 to 0.96, respectively. Several low molecular weight phenolic compounds such as 2,3-diacetyl-1-phenylnaphthalene, ferulic acid, p-hydroxybenzaldoxime, 5-hydroxyvaleric acid, 2,3-diacetyl-1-phenylnaphthalene, and vanillic acid were newly formed in the CP heated at 150 degrees C for 30 min. These results indicated that the antioxidant activity of CP extracts was significantly affected by heating temperature and duration of treatment on CP and that the heating process can be used as a tool for increasing the antioxidant activity of CP.

Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

NASA Technical Reports Server (NTRS)

Shih, K. L.; Souza, K. A.

1978-01-01

The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

Spread of thermal energy and heat sinks: implications for nerve-sparing robotic prostatectomy.

PubMed

Khan, Farhan; Rodriguez, Esequiel; Finley, David S; Skarecky, Douglas W; Ahlering, Thomas E

2007-10-01

During nerve-sparing robot-assisted laparoscopic prostatectomy, nerve injury caused by thermal energy is a concern. Using a porcine model, we studied thermal spread and queried whether vessels such as the prostatic pedicle may act as a heat sink, reducing the spread of thermal energy. Monopolar (MP) and bipolar (BP) cautery was applied laparoscopically on the anterior abdominal wall surface of six pigs with the da Vinci robot. Using fiberoptic thermometry (Luxtron Inc. Santa Clara, CA), temperatures were recorded with and without the interposed inferior epigastric vessels to evaluate the heat sink effect. Interposition of the inferior epigastric vessels definitively demonstrated a heat sink phenomenon: at 7 mm from the MP/BP energy source, temperatures rose 10.7 degrees C to 13.8 degrees C without interposed vessels versus only 1.9 degrees C to 2.5 degrees C when vessels were interposed (P < 0.001). The heat sink phenomenon suggests that the prostatic vascular pedicle should be protective of the neurovascular bundle during transection of the bladder neck during laparoscopic prostatectomy.

Homeothermy and primate bipedalism: is water shortage or solar radiation the main threat to baboon (Papio hamadryas) homeothermy?

PubMed

Mitchell, Duncan; Fuller, Andrea; Maloney, Shane K

2009-05-01

Other than the hominin lineage, baboons are the diurnally active primates that have colonized the arid plains of Africa most successfully. While the hominin lineage adopted bipedalism before colonizing the open, dry plains, baboons retained a quadrupedal mode of locomotion. Because bipedalism has been considered to reduce the thermoregulatory stress of inhabiting open dry plains, we investigated how baboons cope with thermal loads and water restriction. Using implanted data loggers, we measured abdominal temperature every 5 min in six unrestrained baboons while they were exposed to simulated desert conditions (15 degrees C at night rising to 35 degrees C during the day, with and without extra radiant heating), or an ambient temperature of 22 degrees C. At 22 degrees C, core temperature averaged 37.9 degrees C and cycled nychthemerally by 1.7 degrees C. Mean, minimum, and maximum daily core temperatures in euhydrated baboons in the simulated desert environments did not differ from the temperatures displayed in the 22 degrees C environment, even when radiant heating was applied. At 22 degrees C, restricting water intake did not affect core temperature. During the desert simulations, maximum core temperature increased significantly on each day of water deprivation, with the highest temperatures (>40 degrees C) on the third day in the simulation that included radiant heat. When drinking water heated to 38 degrees C was returned, core temperature decreased rapidly to a level lower than normal for that time of day. We conclude that baboons with access to water can maintain homeothermy in the face of high air temperatures and radiant heat loads, but that a lack of access to drinking water poses a major threat to baboon homeothermy. We speculate that any competitive thermoregulatory advantage of bipedalism in early hominins was related to coping with water shortage in hot environments, and that their freed hands might have enabled them to transport enough water to avoid dangerous hyperthermia.

Fluidics and heat generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and advanced medical optics sovereign phacoemulsification systems.

PubMed

Floyd, Michael S; Valentine, Jeremy R; Olson, Randall J

2006-09-01

To study heat generation, vacuum, and flow characteristics of the Alcon Infiniti and Bausch & Lomb Millennium with results compared with the Alcon Legacy and advanced medical optics (AMO) Sovereign machines previously studied. Experimental study. Heat generation with continuous ultrasound was determined with and without a 200-g weight. Flow and vacuum were determined from 12 to 40-ml/min in 2-ml/min steps. The impact of a STAAR Cruise Control was also tested. Millennium created the most heat/20% of power (5.67 +/- 0.51 degrees C unweighted and 6.80 +/- 0.80 degrees C weighted), followed by Sovereign (4.59 +/- 0.70 degrees C unweighted and 5.65 +/- 0.72 degrees C weighted), Infiniti (2.79 +/- 0.62 degrees C unweighted and 3.96 +/- 0.31 degrees C weighted), and Legacy (1.99 +/- 0.49 degrees C unweighted and 4.27 +/- 0.76 degrees C weighted; P < .0001 for all comparisons between machines except Infiniti vs Legacy, both weighted). Flow studies revealed that Millennium Peristaltic was 17% less than indicated (P < .0001 to all other machines), and all other machines were within 3.5% of indicated. Cruise Control decreased flow by 4.1% (P < .0001 for same machine without it). Millennium Venturi had the greatest vacuum (81% more than the least Sovereign; P < .0001), and Cruise Control increased vacuum in a peristaltic machine 35% more than the Venturi system (P < .0001). Percent power is not consistent in regard to heat generation, however, flow was accurate for all machines except Millennium Peristaltic. Restriction with Cruise Control elevates unoccluded vacuum to levels greater than the Venturi system tested.

Intracellular localization of a group II chaperonin indicates a membrane-related function

NASA Technical Reports Server (NTRS)

Trent, Jonathan D.; Kagawa, Hiromi K.; Paavola, Chad D.; McMillan, R. Andrew; Howard, Jeanie; Jahnke, Linda; Lavin, Colleen; Embaye, Tsegereda; Henze, Christopher E.

2003-01-01

Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in cultures grown at 60 degrees C and 76 degrees C or heat-shocked at 85 degrees C by using immunofluorescence microscopy and in thick sections of rapidly frozen cells grown at 76 degrees C by using immunogold electron microscopy. We observed that increased abundance of rosettasomes after heat shock correlated with decreased membrane permeability at lethal temperature (92 degrees C). This change in permeability was not seen in cells heat-shocked in the presence of the amino acid analogue azetidine 2-carboxylic acid, indicating functional protein synthesis influences permeability. Azetidine experiments also indicated that observed heat-induced changes in lipid composition in S. shibatae could not account for changes in membrane permeability. Rosettasomes purified from cultures grown at 60 degrees C and 76 degrees C or heat-shocked at 85 degrees C bind to liposomes made from either the bipolar tetraether lipids of Sulfolobus or a variety of artificial lipid mixtures. The presence of rosettasomes did not significantly change the transition temperature of liposomes, as indicated by differential scanning calorimetry, or the proton permeability of liposomes, as indicated by pyranine fluorescence. We propose that these group II chaperonins function as a structural element in the natural membrane based on their intracellular location, the correlation between their functional abundance and membrane permeability, and their potential distribution on the membrane surface.

Heat‐tolerant Flowering Plants of Active Geothermal Areas in Yellowstone National Park

PubMed Central

STOUT, RICHARD G.; AL‐NIEMI, THAMIR S.

2002-01-01

A broad survey of most of the major geyser basins within Yellowstone National Park (Wyoming, USA) was conducted to identify the flowering plants which tolerate high rhizosphere temperatures (≥40 °C) in geothermally heated environments. Under such conditions, five species of monocots and four species of dicots were repeatedly found. The predominant flowering plants in hot soils (>40 °C at 2–5 cm depth) were grasses, primarily Dichanthelium lanuginosum. Long‐term (weeks to months) rhizosphere temperatures of individual D. lanuginosum above 40 °C were recorded at several different locations, both in the summer and winter. The potential role of heat shock proteins (HSPs) in the apparent adaptation of these plants to chronically high rhizosphere temperatures was examined. Antibodies to cytoplasmic class I small heat shock proteins (sHSPs) and to HSP101 were used in Western immunoblot analyses of protein extracts from plants collected from geothermally heated soils. Relatively high levels of proteins reacting with anti‐sHSP antibodies were consistently detected in root extracts from plants experiencing rhizosphere temperatures above 40 °C, though these proteins were usually not highly expressed in leaf extracts from the same plants. Proteins reacting with antibodies to HSP101 were also present both in leaf and root extracts from plants collected from geothermal soils, but their levels of expression were not as closely related to the degree of heat exposure as those of sHSPs. PMID:12197524

Microstructural examination of irradiated vanadium alloys

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

Gelles, D.S.; Chung, H.M.

1997-04-01

Microstructural examination results are reported for a V-5Cr-5Ti unirradiated control specimens of heat BL-63 following annealing at 1050{degrees}C, and V-4Cr-4Ti heat BL-47 irradiated in three conditions from the DHCE experiment: at 425{degrees}C to 31 dpa and 0.39 appm He/dpa, at 600{degrees}C to 18 dpa and 0.54 appm He/dpa and at 600{degrees}C to 18 dpa and 4.17 appm He/dpa.

The effects of heat treatment on technological properties in Red-bud maple (Acer trautvetteri Medw.) wood.

PubMed

Korkut, Süleyman; Kök, M Samil; Korkut, Derya Sevim; Gürleyen, Tuğba

2008-04-01

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on technological properties of Red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures (120 degrees C, 150 degrees C and 180 degrees C) and for varying durations (2h, 6h and 10h). The technological properties of heat-treated wood samples and control samples were tested. Compression strength parallel to grain, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength, and tension strength perpendicular to grain were determined. The results showed that technological strength values decreased with increasing treatment temperature and treatment times. Red-bud maple wood could be utilized by using proper heat treatment techniques with minimal losses in strength values in areas where working, and stability such as in window frames, are important factors.

HEAT INDUCIBLE EXPRESSION OF ANTIFREEZE PROTEIN GENES FROM THE BEETLES Tenebrio molitor AND Microdera punctipennis.

PubMed

Li, Jieqiong; Ma, Wenjing; Ma, Ji

2016-01-01

Antifreeze proteins (AFPs) play important roles in protecting poikilothermic organisms from cold damage. The expression of AFP genes (afps) is induced by low temperature. However, it is reported that heat can influence the expression of afps in the desert beetle Microdera punctipennis. To further detect whether heat also induce the expression of afps in other insects, and to determine the expression profiling of insect afps at different temperatures. The expression of antifreeze protein genes in the two beetles, Microdera punctipennis and Tenebrio molitor that have quite different living environment, under different temperatures were studied by using real-time quantitative PCR. Mild low temperatures (5~15 degree C), high temperature (38~47 degree C for M. punctipennis, or 37~42 degree C for T. molitor) and temperature difference (10~30 degree C) all stimulated strongly to the expression of AFP genes (Mpafps) in M. punctipennis which lives in the wild filed in desert. The mRNA level of Mpafps after M. punctipennis were exposed to these temperatures for 1h~5h was at least 30-fold of the control at 25 degree C. For T. molitor which is breeding in door with wheat bran all these temperatures stimulated significantly to the expression of Tmafps, while the extent and degree of the temperature stimulation on Tmafps expression were much lower than on Mpafps. After T. molitor were exposed to 5 degree C and 15 degree C for 1h~5h, the mRNA level of Tmafps was over 6-fold and 45-fold of the control at 25 degree C. High temperature (37~42 degree C) for 1h~3h treatments increased Tmafps mRNA level 4.8-fold of the control. Temperature difference of 10 degree C was effective in stimulating Tmafps expression. The expression of insect antifreeze protein genes both in M. punctipennis and T. molitor was induced by heat, suggesting that this phenomenon may be common in insects; the extent and degree of the influence differ in species that have different living conditions. The heat inducible expression of antifreeze protein genes hints that antifreeze proteins may involve in other functions except for antifreeze.

Microstructures and mechanical properties of powder injection molded Ti-6Al-4V/HA powder.

PubMed

Thian, E S; Loh, N H; Khor, K A; Tor, S B

2002-07-01

Taguchi method with an L9 orthogonal array was employed to investigate the sintered properties of Ti-6Al-4V/HA tensile bars produced by powder injection molding. The effects of sintering factors at the 90% significance level: sintering temperature (1050 degrees C, 1100 degrees C and 1150 degrees C), heating rate (5 degrees C/min, 7.5 degrees C/min and 10 degrees C/min), holding time (30, 45 and 60 min) and cooling rate (5 degrees C/min, 20 degrees C/min and 40 degrees C/min) were investigated. Results showed that sintering temperature, heating rate and cooling rate have significant effects on sintered properties, whereas the influence of holding time was insignificant. It was found that a sintering temperature of 1100 degrees C, a heating rate of 7.5 degrees C/min and a cooling rate of 5 degrees C/min increased the relative density, Vicker's microhardness, flexural strength and flexural modulus. However, a further increment of sintering temperature to 1150 degrees C did not show any discernable improvement in the relative density and Vicker's microhardness, but there was a slight increase of 0.6% and 0.9% in the flexural strength and flexural modulus, respectively. Mechanically strong Ti-6Al-4V/HA parts with an open porosity of around 50% were developed.

Susceptibility of Plodia interpunctella (Lepidoptera: Pyralidae) developmental stages to high temperatures used during structural heat treatments.

PubMed

Mahroof, R; Subramanyam, B

2006-12-01

Heating the ambient air of a whole, or a portion of a food-processing facility to 50 to 60 degrees C and maintaining these elevated temperatures for 24 to 36 h, is an old technology, referred to as heat treatment. There is renewed interest in adopting heat treatments around the world as a viable insect control alternative to fumigation with methyl bromide. There is limited published information on responses of the Indian meal moth, Plodia interpunctella (Hübner), exposed to elevated temperatures typically used during heat treatments. Time-mortality relationships were determined for eggs, fifth-instars (wandering-phase larvae), pupae, and adults of P. interpunctella exposed to five constant temperatures between 44 and 52 degrees C. Mortality of each stage increased with increasing temperature and exposure time. In general, fifth-instars were the most heat-tolerant stage at all temperatures tested. Exposure for a minimum of 34 min at 50 degrees C was required to kill 99% of the fifth-instars. It is proposed that heat treatments aimed at controlling fifth-instars should be able to control all other stages of P. interpunctella.

Mechanism of microwave sterilization in the dry state.

PubMed Central

Jeng, D K; Kaczmarek, K A; Woodworth, A G; Balasky, G

1987-01-01

With an automated computerized temperature control and a specialized temperature measurement system, dry spores of Bacillus subtilis subsp. niger were treated with heat simultaneously in a convection dry-heat oven and a microwave oven. The temperature of the microwave oven was monitored such that the temperature profiles of the spore samples in both heat sources were nearly identical. Under these experimental conditions, we unequivocally demonstrated that the mechanism of sporicidal action of the microwaves was caused solely by thermal effects. Nonthermal effects were not significant in a dry microwave sterilization process. Both heating systems showed that a dwelling time of more than 45 min was required to sterilize 10(5) inoculated spores in dry glass vials at 137 degrees C. The D values of both heating systems were 88, 14, and 7 min at 117, 130, and 137 degrees C, respectively. The Z value was estimated to be 18 degrees C. PMID:3118807

Field evaluation and assessment of thermal energy storage for residential space heating

NASA Astrophysics Data System (ADS)

Hersh, H. N.

1982-02-01

A data base was developed based on two heating seasons and 45 test and 30 control homes in Maine and Vermont. Based on first analysis of monitored temperatures and electrical energy used for space heating, fuel bills and reports of users and utilities, the technical performance of TES ceramic and hydronic systems is deemed to be technically satisfactory and there is a high degree of customer acceptance and positive attitudes towards TES. Analysis of house data shows a high degree of variability in electric heat energy demand for a given degree-day. An analysis is underway to investigate relative differences in the efficiency of electricity utilization of storage and direct heating devices. The much higher price of storge systems relative to direct systems is an impediment to market penetration. A changing picture of rate structures may encourage direct systems at the expense of storage systems.

Optimizing Mouse Surgery with Online Rectal Temperature Monitoring and Preoperative Heat Supply. Effects on Post-Ischemic Acute Kidney Injury

PubMed Central

Holderied, Alexander; Anders, Hans-Joachim

2016-01-01

Body temperature affects outcomes of tissue injury. We hypothesized that online body core temperature recording and selective interventions help to standardize peri-interventional temperature control and the reliability of outcomes in experimental renal ischemia reperfusion injury (IRI). We recorded core temperature in up to seven mice in parallel using a Thermes USB recorder and ret-3-iso rectal probes with three different protocols. Setup A: Heating pad during ischemia time; Setup B: Heating pad from incision to wound closure; Setup C: A ventilated heating chamber before surgery and during ischemia time with surgeries performed on a heating pad. Temperature profile recording displayed significant declines upon installing anesthesia. The profile of the baseline experimental setup A revealed that <1% of the temperature readings were within the target range of 36.5 to 38.5°C. Setup B and C increased the target range readings to 34.6 ± 28.0% and 99.3 ± 1.5%, respectively. Setup C significantly increased S3 tubular necrosis, neutrophil influx, and mRNA expression of kidney injury markers. In addition, using setup C different ischemia times generated a linear correlation with acute tubular necrosis parameters at a low variability, which further correlated with the degree of kidney atrophy 5 weeks after surgery. Changing temperature control setup A to C was equivalent to 10 minutes more ischemia time. We conclude that body temperature drops quickly in mice upon initiating anesthesia. Immediate heat supply, e.g. in a ventilated heating chamber, and online core temperature monitoring can help to standardize and optimize experimental outcomes. PMID:26890071

Work of breathing during CPAP and heated humidified high-flow nasal cannula.

PubMed

Shetty, Sandeep; Hickey, Ann; Rafferty, Gerrard F; Peacock, Janet L; Greenough, Anne

2016-09-01

To determine whether continuous positive airway pressure (CPAP) compared with heated humidified, high-flow nasal cannula (HHFNC) in infants with evolving or established bronchopulmonary dysplasia (BPD) reduced the work of breathing (WOB) and thoracoabdominal asynchrony (TAA) and improved oxygen saturation (SaO2). Randomised crossover study. Tertiary neonatal unit. 20 infants (median gestational age of 27.6 weeks (range 24.6-31.9 weeks)) were studied at a median postnatal age of 30.9 weeks (range 28.1-39.1 weeks). Infants were studied on 2 consecutive days. On the first study day, they were randomised to either CPAP or HHFNC each for 2 h, the order being reversed on the second day. The WOB was assessed by measuring the pressure time product of the diaphragm (PTPdi). PTPdi, TAA and SaO2 were assessed during the final 5 min of each 2 h period and the results on the two study days were meaned. There were no significant differences in the results on CPAP versus HHFNC: mean PTPdi 226 (range 126-294) versus 224 cm H2O/s/min (95% CI for difference: -27 to 22; p=0.85) (range 170-318) (p=0.82), mean TAA 13.4° (range 4.51°-23.32°) versus 14.01° (range 4.25°-23.86°) (95% CI for difference: -3.9 to 2.8: p=0.73) (p=0.63) and mean SaO2 95% (range 93%-100%) versus 95% (94%-99%), (95% CI for difference -1.8 to 0.5; p=0.25) (p=0.45). In infants with evolving or established BPD, CPAP compared with HHFNC offered no significant advantage with regard to the WOB, degree of asynchrony or oxygen saturation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

An axisymmetric analog two-layer convective heating procedure with application to the evaluation of Space Shuttle Orbiter wing leading edge and windward surface heating

NASA Technical Reports Server (NTRS)

Wang, K. C.

1994-01-01

A numerical procedure for predicting the convective heating rate of hypersonic reentry vehicles is described. The procedure, which is based on the axisymmetric analog, consists of obtaining the three-dimensional inviscid flowfield solution; then the surface streamlines and metrics are calculated using the inviscid velocity components on the surface; finally, an axisymmetric boundary layer code or approximate convective heating equations are used to evaluate heating rates. This approach yields heating predictions to general three-dimensional body shapes. The procedure has been applied to the prediction of the wing leading edge heating to the Space Shuttle Orbiter. The numerical results are compared with the results of heat transfer testing (OH66) of an 0.025 scale model of the Space Shuttle Orbiter configuration in the Calspan Hypersonic Shock Tunnel (HST) at Mach 10 and angles of attack of 30 and 40 degrees. Comparisons with STS-5 flight data at Mach 9.15 and angle of attack of 37.4 degrees and STS-2 flight data at Mach 12.86 and angle of attack of 39.7 degrees are also given.

Effect of ultrahigh-temperature continuous ohmic heating treatment on fresh orange juice.

PubMed

Leizerson, Shirly; Shimoni, Eyal

2005-05-04

The scope of this study is the effect of ohmic heating thermal treatment on liquid fruit juice made of oranges. Effects of ohmic heating on the quality of orange juice were examined and compared to those of heat pasteurization at 90 degrees C for 50 s. Orange juice was treated at temperatures of 90, 120, and 150 degrees C for 1.13, 0.85, and 0.68 s in an ohmic heating system. Microbial counts showed complete inactivation of bacteria, yeast, and mold during ohmic and conventional treatments. The ohmic heating treatment reduced pectin esterase activity by 98%. The reduction in vitamin C was 15%. Ohmic-heated orange juice maintained higher amounts of the five representative flavor compounds than did heat-pasteurized juice. Sensory evaluation tests showed no difference between fresh and ohmic-heated orange juice. Thus, high-temperature ohmic-heating treatment can be effectively used to pasteurize fresh orange juice with minimal sensory deterioration.

Solar heating system

DOEpatents

Schreyer, James M.; Dorsey, George F.

1982-01-01

An improved solar heating system in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75.degree. to 180.degree. F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing and releasing heat for distribution.

Effects of occupational heat exposure on female brick workers in West Bengal, India

PubMed Central

Sett, Moumita; Sahu, Subhashis

2014-01-01

Background Manual brick-manufacturing units in India engage a large number of female workers on a daily-wage basis for a period of 8 months per year. There are two groups of female workers in the brickfields: the brick molders and the brick carriers. These brickfields are mostly unorganized, and the workers are exposed to extreme conditions such as very high seasonal heat. The present trend of increasing temperatures, as a result of global warming and climate change, will put an additional burden on them. Objective This study aims to evaluate the effect of workplace heat exposure on the well-being, physiological load, and productivity of female brickfield workers in India. Design A questionnaire study (n=120), environmental temperature, and weekly work productivity analyses were evaluated for 8 months in the brickfields. Cardiac strain and walking speed (subset, n=40) were also studied and compared in hotter and colder days amongst the female brickfield workers. Results The subjects experience summer for about 5 months with additional heat stress radiating from the brick kiln. The weekly productivity data show a linear decline in productivity with increased maximum air temperature above 34.9°C. The cardiac parameters (peak heart rate (HRp), net cardiac cost (NCC), relative cardiac cost (RCC), and recovery heart rates) were significantly higher on hotter days (Wet Bulb Globe Temperature (WBGTout) index: 26.9°C to 30.74°C) than on cooler days (WBGTout index: 16.12°C to 19.37°C) for the brick molders; however, this is not the case for the brick carriers. As the brick carriers adapt to hotter days by decreasing their walking speed, their productivity decreases. Conclusion We conclude that high heat exposure in brickfields during summer caused physiological strain in both categories of female brickfield workers. A coping strategy employed by the brick carriers was to reduce their walking speed and thus lose part of their earnings. The lost productivity for every degree rise in temperature is about 2% in the brickfields. This reduction will be exacerbated by climate change and may undermine the quality of life of female brickfield workers. PMID:24499742

Effects of occupational heat exposure on female brick workers in West Bengal, India.

PubMed

Sett, Moumita; Sahu, Subhashis

2014-01-01

Manual brick-manufacturing units in India engage a large number of female workers on a daily-wage basis for a period of 8 months per year. There are two groups of female workers in the brickfields: the brick molders and the brick carriers. These brickfields are mostly unorganized, and the workers are exposed to extreme conditions such as very high seasonal heat. The present trend of increasing temperatures, as a result of global warming and climate change, will put an additional burden on them. This study aims to evaluate the effect of workplace heat exposure on the well-being, physiological load, and productivity of female brickfield workers in India. A questionnaire study (n=120), environmental temperature, and weekly work productivity analyses were evaluated for 8 months in the brickfields. Cardiac strain and walking speed (subset, n=40) were also studied and compared in hotter and colder days amongst the female brickfield workers. The subjects experience summer for about 5 months with additional heat stress radiating from the brick kiln. The weekly productivity data show a linear decline in productivity with increased maximum air temperature above 34.9°C. The cardiac parameters (peak heart rate (HRp), net cardiac cost (NCC), relative cardiac cost (RCC), and recovery heart rates) were significantly higher on hotter days (Wet Bulb Globe Temperature (WBGTout) index: 26.9°C to 30.74°C) than on cooler days (WBGTout index: 16.12°C to 19.37°C) for the brick molders; however, this is not the case for the brick carriers. As the brick carriers adapt to hotter days by decreasing their walking speed, their productivity decreases. We conclude that high heat exposure in brickfields during summer caused physiological strain in both categories of female brickfield workers. A coping strategy employed by the brick carriers was to reduce their walking speed and thus lose part of their earnings. The lost productivity for every degree rise in temperature is about 2% in the brickfields. This reduction will be exacerbated by climate change and may undermine the quality of life of female brickfield workers.

Heat transfer from an oxidized large copper surface to liquid helium: Dependence on surface orientation and treatment

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

Iwamoto, A.; Mito, T.; Takahata, K.

Heat transfer of large copper plates (18 x 76 mm) in liquid helium has been measured as a function of orientation and treatment of the heat transfer surface. The results relate to applications of large scale superconductors. In order to clarify the influence of the area where the surface treatment peels off, the authors studied five types of heat transfer surface areas including: (a) 100% polished copper sample, (b) and (c) two 50% oxidized copper samples having different patterns of oxidation, (d) 75% oxidized copper sample, (e) 90% oxidized copper sample, and (f) 100% oxidized copper sample. They observed thatmore » the critical heat flux depends on the heat transfer surface orientation. The critical heat flux is a maximum at angles of 0{degrees} - 30{degrees} and decreases monotonically with increasing angles above 30{degrees}, where the angle is taken in reference to the horizontal axis. On the other hand, the minimum heat flux is less dependent on the surface orientation. More than 75% oxidation on the surface makes the critical heat flux increase. The minimum heat fluxes of the 50 and 90% oxidized Cu samples approximately agree with that of the 100% oxidized Cu sample. Experiments and calculations show that the critical and the minimum heat fluxes are a bilinear function of the fraction of oxidized surface area.« less

Effects of Dark Brooders on Behavior and Fearfulness in Layers

PubMed Central

Riber, Anja B.; Guzman, Diego A.

2016-01-01

Simple Summary Chicks require heat to maintain body temperature during the first weeks after hatch. Heat is normally provided by use of heating lamps or whole-house heating, but an alternative is dark brooders, i.e. horizontal heating elements equipped with curtains. The effects of providing layer chicks with dark brooders during the brooding period on behavior and fearfulness were investigated. Brooders resulted in chicks showing less locomotive activity, feather pecking and fleeing. Also, a long-term reduction of fearfulness in brooder birds was found. Results support the suggestion that rearing with dark brooders can be a successful method of reducing or preventing some of the major welfare problems in layers. Abstract Chicks require heat to maintain body temperature during the first weeks after hatch. This may be provided by dark brooders; i.e., horizontal heating elements equipped with curtains. The objective was to test effects of rearing layer chicks with dark brooders on time budget and fearfulness. Behavioral observations were performed during the first six weeks of age. Three different fear tests were conducted when the birds were age 3–6, 14–15 and 26–28 weeks. During the first four days, brooder chicks rested more than control chicks whereas they spent less time drinking, feather pecking and on locomotion (p ≤ 0.009). On days 16, 23, 30 and 42, brooder chicks spent less time on feather pecking, locomotion and fleeing (p ≤ 0.01) whereas foraging and dust bathing occurred more often on day 42 (p ≤ 0.032). Brooder birds had shorter durations of tonic immobility at all ages (p = 0.0032), moved closer to the novel object at age 15 weeks (p < 0.0001), and had shorter latencies to initiate locomotion in the open-field test at age 28 weeks (p < 0.0001). Results support the suggestion that dark brooders can be a successful method of reducing or preventing fear and feather pecking in layers. PMID:26751482

Human thermoregulatory function during exercise and immersion after 35 days of horizontal bed-rest and recovery.

PubMed

Mekjavic, Igor B; Golja, Petra; Tipton, Michael J; Eiken, Ola

2005-10-01

The present study evaluated the effect of 35 days of experimental horizontal bed-rest on exercise and immersion thermoregulatory function. Fifteen healthy male volunteers were assigned to either a Control (n = 5) or Bed-rest (n = 10) group. Thermoregulatory function was evaluated during a 30-min bout of submaximal exercise on a cycle ergometer, followed immediately by a 100-min immersion in 28 degrees C water. For the Bed-rest group, exercise and immersion thermoregulatory responses observed post-bed-rest were compared with those after a 5 week supervised active recovery period. In both trials, the absolute work load during the exercise portion of the test was identical. During the exercise and immersion, we recorded skin temperature, rectal temperature, the difference in temperature between the forearm and third digit of the right hand (DeltaT(forearm-fingertip))--an index of skin blood flow, sweating rate from the forehead, oxygen uptake and heart rate at minute intervals. Subjects provided ratings of temperature perception and thermal comfort at 5-min intervals. Exercise thermoregulatory responses after bed-rest and recovery were similar. Subjective ratings of temperature perception and thermal comfort during immersion indicated that subjects perceived similar combinations of Tsk and Tre to be warmer and thermally less uncomfortable after bed-rest. The average (SD) exercise-induced increase in Tre relative to resting values was not significantly different between the Post-bed-rest (0.4 (0.2) degrees C) and Recovery (0.5 (0.2) degrees C) trials. During the post-exercise immersion, the decrease in Tre, relative to resting values, was significantly (P < 0.05) greater in the Post-bed-rest trial (0.9 (0.5) degrees C) than after recovery (0.4 (0.3) degrees C). DeltaT(forearm-fingertip) was 5.2 (0.9) degrees C and 5.8 (1.0) degrees C at the end of the post-bed-rest and recovery immersions, respectively. The gain of the shivering response (increase in VO(2) relative to the decrease in Tre; VO(2)/Tre) was 1.19 l min(-1) degrees C(-1) in the Recovery trial, and was significantly attenuated to 0.51 l min(-1) degrees C(-1) in the Post-bed-rest trial. The greater cooling rate observed in the post-bed-rest trial is attributed to the greater heat loss and reduced heat production. The former is the result of attenuated cold-induced vasoconstriction and enhanced sweating rate, and the latter a result of a lower shivering VO(2) response.

Interface modification during oxidation of a glass-ceramic matrix/SiC fibre composite

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

Daniel, A.M.; Martin-Meizoso, A.; Plucknett, K.P.

Oxidation heat treatments between 375{degrees}C and 600{degrees}C for 100 hours in air, have been performed on the calcium aluminosilicate glass-ceramic matrix/SiC fibre reinforced composite CAS/Nicalon (manufactured by Corning, USA). Using a commercial nano-indentation system to perform fibre push-down tests, the fibre-matrix interfacial debond fracture surface energy (G{sub i}) and frictional shear stress ({tau}) have been determined. Modification of interface properties, compared to the as-fabricated material, was observed at heat treatment temperatures as low as 375{degrees}C, where a significant drop in G{sub i} and an increase in {tau} were recorded. With 450{degrees}C, 525{degrees}C and 600{degrees}C heat treatments, an increase in G{submore » i} but a dramatic increase in {tau} were recorded. Under four-point flexure testing, the as fabricated and the 375{degrees}C heat treated materials displayed tough, composite behaviour with extensive fibre pull out, but at {ge}450{degrees}C, brittle failure with minimal fibre pull out, was observed. This transition from tough mechanical response to one of brittleness is due to the large increase in {tau} reducing fibre pull out to a minimum and therefore reducing the total required work of fracture. The large increases in {tau} and G{sub i} have been attributed to the oxidative removal of the lubricating, carbon interface and the compressive residual stresses across the interface.« less

Interface modification during oxidation of a glass-ceramic matrix/SiC fibre composite

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

Daniel, A.M.; Martin-Meizoso, A.; Plucknett, K.P.

Oxidation heat treatments between 375{degrees}C and 600{degrees}C for 100 hours in air, have been performed on the calcium aluminosilicate glass-ceramic matrix/SiC fibre reinforced composite CAS/Nicalon (manufactured by Coming, USA). Using a commercial nano-indentation system to perform fibre push-down tests, the fibre-matrix interfacial debond fracture surface energy (G{sub i}) and frictional shear stress ({tau}) have been determined. Modification of interface properties, compared to the as fabricated material, was observed at heat treatment temperatures as low as 375{degrees}C, where a significant drop in G{sub i} and an increase in {tau} were recorded. With 450{degrees}C, 525{degrees}C and 600{degrees}C heat treatments, an increase inmore » G{sub i} but a dramatic increase in {tau} were recorded. Under four-point flexure testing, the as fabricated and the 375{degrees}C heat treated materials displayed tough, composite behaviour with extensive fibre pull out, but at {le}450{degrees}C, brittle failure with minimal fibre pull out, was observed. This transition from tough mechanical response to one of brittleness is due to the large increase in {tau} reducing fibre pull out to a minimum and therefore reducing the total required work of fracture. The large increases in {tau} and G{sub i} have been attributed to the oxidative removal of the lubricating, carbon interface and the compressive residual stresses across the interface.« less

Regional blood flow in sea turtles: implications for heat exchange in an aquatic ectotherm.

PubMed

Hochscheid, Sandra; Bentivegna, Flegra; Speakman, John R

2002-01-01

Despite substantial knowledge on thermoregulation in reptiles, the mechanisms involved in heat exchange of sea turtles have not been investigated in detail. We studied blood flow in the front flippers of two green turtles, Chelonia mydas, and four loggerhead turtles, Caretta caretta, using Doppler ultrasound to assess the importance of regional blood flow in temperature regulation. Mean blood flow velocity and heart rate were determined for the water temperature at which the turtles were acclimated (19.3 degrees-22.5 degrees C) and for several experimental water temperatures (17 degrees-32 degrees C) to which the turtles were exposed for a short time. Flipper circulation increased with increasing water temperature, whereas during cooling, flipper circulation was greatly reduced. Heart rate was also positively correlated with water temperature; however, there were large variations between individual heart rate responses. Body temperatures, which were additionally determined for the two green turtles and six loggerhead turtles, increased faster during heating than during cooling. Heating rates were positively correlated with the difference between acclimation and experimental temperature and negatively correlated with body mass. Our data suggest that by varying circulation of the front flippers, turtles are capable of either transporting heat quickly into the body or retaining heat inside the body, depending on the prevailing thermal demands.

Formulation of stable Bacillus subtilis AH18 against temperature fluctuation with highly heat-resistant endospores and micropore inorganic carriers.

PubMed

Chung, Soohee; Lim, Hyung Mi; Kim, Sang-Dal

2007-08-01

To survive the commercial market and to achieve the desired effect of beneficial organisms, the strains in microbial products must be cost-effectively formulated to remain dormant and hence survive through high and low temperatures of the environment during transportation and storage. Dormancy and stability of Bacillus subtilis AH18 was achieved by producing endospores with enhanced heat resistance and using inorganic carriers. Heat stability assays, at 90 degrees C for 1 h, showed that spores produced under a sublethal temperature of 57 degrees C was 100 times more heat-resistant than the ones produced by food depletion at the growing temperature of 37 degrees C. When these highly heat-resistant endospores were formulated with inorganic carriers of natural and synthetic zeolite or kaolin clay minerals having substantial amount of micropores, the dormancy of the endospores was maintained for 6 months at 15-25 degrees C. Meanwhile, macroporous perlite carriers with average pore diameter larger than 3.7 microm stimulated the germination of the spores and rapid proliferation of the bacteria. These results indicated that a B. subtilis AH18 product that can remain dormant and survive through environmental temperature fluctuation can be formulated by producing heat-stressed endospores and incorporating inorganic carriers with micropores in the formulation step.

Development of thermotolerance in CHO cells: modification by procaine.

PubMed

Rastogi, D; Henle, K J; Nagle, W A; Moss, A J; Neilan, B A; Rastogi, S P

1987-01-01

We have tested the reported ability of procaine to inhibit the induction and the development of thermotolerance in Chinese hamster ovary cells. Thermotolerance was induced either by hyperthermia alone (10 min, 45 degrees C) or by combining hyperthermia and procaine (5 min, 45 degrees C + 10 mM procaine) with heating times adjusted to yield similar cell survival after the conditioning treatments. Both the kinetics of thermotolerance development in fresh medium without procaine and the magnitude of thermotolerance 6 h after heat conditioning were similar for the two treatment groups. Development of thermotolerance in the presence of procaine was tested by adding the drug at 5 or 10 mM to culture medium between, but not during two fractionated heat treatments. Thermotolerance development was observed even in the presence of 10 mM procaine, but only if cell survival was corrected for the 37 degrees C-procaine toxicity. Complete survival curves of cells incubated for 6 h at 37 degrees C in 7.5 mM procaine between heat conditioning and test heating showed a D0 that was only 35 per cent lower than that of thermotolerant controls. The data are consistent with the reported sensitization to heat killing by procaine, but show that thermotolerance induction and development were only minimally perturbed by procaine.

Fire fighting and its influence on the body.

PubMed

Rossi, René

2003-08-15

Working conditions for fire fighters can be described according to the environment temperature and the incident radiant heat flux. Measurements for this study in buildings for fire fighting training have shown that fire fighters are typically exposed to radiant heat fluxes of between 5 and 10 kWm(-2) during this kind of exercise. The heat load can nevertheless be much higher. In one case, 42 kWm(-2) was measured. The temperatures reached between 100 and 190 degrees C at 1 m above ground, going up to 278 degrees C in one case. Human trials have been performed with 17 fire fighters. After exercises (about 15 min) in a heated room, the mean core temperature of the fire fighters rose by 0.6 degrees C with a surrounding temperature of 31 degrees C and 1.0 degrees C with 38 degrees C. The sweat production varied from 0.7 to 2.1 lh(-1); 16% to 45% of sweat remained in the clothing layers. During the exercises in the training buildings, a mean of 48 degrees C has been measured between fire fighters' clothing and workwear. These conditions lead to an increase of the relative humidity in all the jackets up to 100%. When the fire fighters came out of the fire, the humidity remained at this level in the PVC coated jackets while it was in some cases strongly reduced in breathable jackets.

Testicular heat exposure enhances the suppression of spermatogenesis by testosterone in rats: the "two-hit" approach to male contraceptive development.

PubMed

Lue, Y; Hikim, A P; Wang, C; Im, M; Leung, A; Swerdloff, R S

2000-04-01

The objectives of the study were to determine stage-specific changes in the kinetics of germ cell apoptosis induced by administration of exogenous testosterone (T) alone and to examine whether addition of a single testicular heat exposure would enhance the induction of germ cell apoptosis and the suppression of spermatogenesis by T. Adult male rats were implanted with 3-cm SILASTIC brand capsules (Dow Corning Corp.) containing T for up to 6 weeks. Intratesticular T levels declined to 2.9% of control values by 1 week and remained suppressed at 2, 3, and 6 weeks after T administration. The incidence of germ cell apoptosis (expressed as numbers per 100 Sertoli cells) was low in control rats (0-9.52). After T treatment, the mean incidence of apoptosis at stages VII-VIII increased significantly by 1 week (21.43 +/-3.33) and showed further increases by 6 weeks (56.30 +/- 7.47); apoptotic rates remained low at early (I-VI) and later (XII-XIV) stages. To test whether the combination of T with a single testicular heat exposure resulted in more complete suppression of spermatogenesis than either treatment alone, four groups of adult rats received one of the following treatments: 1) a subdermal empty polydimethylsilozane implant, 2) exposure to a single testicular heating (43 C for 15 min) applied on day 14, 3) 3-cm T implant, or 4) 3-cm T implant and a single testicular heat exposure (applied on day 14). All animals were killed at the end of 6 weeks. In the heat-treated group, testis weight and testicular sperm counts were decreased to 65.4% and 28.9% of control levels, respectively. The corresponding values in the T-treated group were 49.7% and 24.9% of control levels, respectively. Notably, addition of heat to T further reduced testis weight to 31.1% of control levels and testicular sperm counts to near zero. Histomorphometric analysis showed that all treatments reduced seminiferous tubular diameter and epithelial and luminal volume, with the greatest decrease after combined T and heat treatment. Heat exposure in animals bearing T implants markedly reduced the number of pachytene spermatocytes and round spermatids through apoptosis, resulting in tubules devoid of mature spermatids. Spermatogonia and preleptotene spermatocytes remained unaffected. These results clearly demonstrate that 1) exogenous T reduces intratesticular T and induces apoptosis mainly at stages VII-VIII within 1-6 weeks; 2) the combined treatment of T and heat markedly inhibits spermatogenesis, resulting in near azoospermia within 6 weeks; and 3) meiosis and spermiogenesis are the most vulnerable phases of spermatogenesis in response to T plus heat treatment. These findings suggest that a combination of hormonal treatment such as T and a physical agent (heat exposure) is more effective in suppressing spermatogenesis than either treatment alone. We hypothesize that combination of two antispermatogenic agents ("two hit") working at separate stages of the spermatogenic cycle will lead to greater male contraceptive efficacy.

Heat propagation in dentin during instrumentation with different sonic scaler tips.

PubMed

Kocher, T; Plagmann, H C

1996-04-01

It is important to know how much heat is generated when a root surface is debrided with sonic scalers and if that heat can be released satisfactorily into the environment. The temperature changes that occurred in dentinal specimens treated with two different sonic scaler tips, used with and without coolant, were studied. Temperature increases of up to 4 degrees C were observed for both tips when a coolant was used. Heat propagation during instrumentation was dependent to a considerable degree on the temperature of the coolant. Sonic scalers should not be used without coolant, because the dentinal temperature may increase up to 35 degrees C, depending on the force of application. A high positive linear correlation was found between increase in temperature and force of application.

Ultrastructural study of mitochondrial damage in CHO cells exposed to hyperthermia.

PubMed

Cole, A; Armour, E P

1988-09-01

A unique direct-view stereo electron microscope technique was used to visualize the structure and three-dimensional distributions of mitochondria in CHO cells in situ following hyperthermic treatments. Aberrations induced by various heating regimens were recorded. The protocol included a trypsin digestion that may have enhanced the expression of the initial heat damage. The developed damage was observed as increasing levels of mitochondrial distortion, swelling, and dissociation. Minimal damage was induced at 42 degrees C for exposures of up to 4 h, while significant damage was induced at 43 degrees C for exposures of more than 30 min and at 45 degrees C for exposures of more than 10 min. For moderate exposures, a partial recovery of mitochondrial integrity was observed when the heat treatment was followed by incubation at 37 degrees C for 24 h. Mitochondrial damage was related to the heat dose in that increasing treatment temperature resulted in greater damage, but when compared to cell survival the damage did not parallel cell killing under all time-temperature conditions.

Lithium-ion battery structure that self-heats at low temperatures

NASA Astrophysics Data System (ADS)

Wang, Chao-Yang; Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Ji, Yan; Yang, Xiao-Guang; Leng, Yongjun

2016-01-01

Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the ‘all-climate battery’ cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

Lithium-ion battery structure that self-heats at low temperatures.

PubMed

Wang, Chao-Yang; Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Ji, Yan; Yang, Xiao-Guang; Leng, Yongjun

2016-01-28

Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the 'all-climate battery' cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

A Preliminary Study of the Prevention of Ice on Aircraft by the Use of Engine-exhaust Heat

NASA Technical Reports Server (NTRS)

Rodert, Lewis A

1939-01-01

An investigation was made in the N.A.C.A. ice tunnel at air temperatures from 20 degrees to 28 degrees Fahrenheit and at a velocity of 80 miles per hour to determine whether ice formations on a model wing could be prevented by the use of the heat from the engine-exhaust gas. Various spanwise duct systems were tested in a 6-foot-chord N.A.C.A. 23012 wing model. The formation of ice over the entire wing chord was prevented by the direct heating of the forward 10 percent of the wing by hot air, which was passed through leading-edge ducts. Under dry conditions, enough heat to maintain the temperature of the forward 10 percent of the wing at about 200 degrees Fahrenheit above that of the ambient air was required for the prevention of ice formation. The air temperature in the ducts that was necessary to produce these skin temperatures varied from 360 degrees to 834 degrees Fahrenheit; the corresponding air velocities in the duct were 152 and 45 feet per second. Ice formations at the leading edge were locally prevented by air that passed over the interior of the wing surface at a velocity of 30 feet per second and a temperature of 122 degrees Fahrenheit.

Heat wave over India during summer 2015: an assessment of real time extended range forecast

NASA Astrophysics Data System (ADS)

Pattanaik, D. R.; Mohapatra, M.; Srivastava, A. K.; Kumar, Arun

2017-08-01

Hot winds are the marked feature of summer season in India during late spring preceding the climatological onset of the monsoon season in June. Some years the conditions becomes very vulnerable with the maximum temperature ( T max) exceeding 45 °C for many days over parts of north-western, eastern coastal states of India and Indo-Gangetic plain. During summer of 2015 (late May to early June) eastern coastal states, central and northwestern parts of India experienced severe heat wave conditions leading to loss of thousands of human life in extreme high temperature conditions. It is not only the loss of human life but also the animals and birds were very vulnerable to this extreme heat wave conditions. In this study, an attempt is made to assess the performance of real time extended range forecast (forecast up to 3 weeks) of this scorching T max based on the NCEP's Climate Forecast System (CFS) latest version coupled model (CFSv2). The heat wave condition was very severe during the week from 22 to 28 May with subsequent week from 29 May to 4 June also witnessed high T max over many parts of central India including eastern coastal states of India. The 8 ensemble members of operational CFSv2 model are used once in a week to prepare the weekly bias corrected deterministic (ensemble mean) T max forecast for 3 weeks valid from Friday to Thursday coinciding with the heat wave periods of 2015. Using the 8 ensemble members separately and the CFSv2 corresponding hindcast climatology the probability of above and below normal T max is also prepared for the same 3 weeks. The real time deterministic and probabilistic forecasts did indicate impending heat wave over many parts of India during late May and early June of 2015 associated with strong northwesterly wind over main land mass of India, delaying the sea breeze, leading to heat waves over eastern coastal regions of India. Thus, the capability of coupled model in providing early warning of such killer heat wave can be very useful to the disaster managers to take appropriate actions to minimize the loss of life and property due to such high T max.

On the development of two characteristically different crystal morphology in SiO(2)-MgO-Al (2)O (3)-K (2)O-B (2)O (3)-F glass-ceramic system.

PubMed

Roy, Shibayan; Basu, Bikramjit

2009-01-01

The present work demonstrates how crystals with two different characteristic morphologies can be formed in SiO(2)-MgO-Al(2)O(3)-K(2)O-B(2)O(3)-F glass-ceramic system by adopting two sets of heat treatment experiments. In our study, single stage heat treatment experiments were performed at 1,000 degrees C for varying holding time of 8-24 h with 4 h time interval and as a function of temperature in the range of 1,000-1,120 degrees C with 40 degrees C temperature interval. The constant heating rate of 10 degrees C/min was employed for both sets of experiments. The microstructural changes were investigated using Fourier transformed infrared spectroscopy (FT-IR), SEM-EDS and XRD. For temperature variation batches, the microstructure is characterized by interlocked, randomly oriented mica plates ('house-of-cards' morphology). An important and new observation of complex crystal morphology is made in the samples heat treated at 1,000 degrees C for varying holding times. Such morphology appears to be the results of composite spherulitic-dendritic like growth of mica rods radiating from a central nucleus. The possible mechanism for such characteristic crystal growth morphology is discussed with reference to a nucleation-growth kinetics based model. The activation energy for crystal nucleation and Avrami index are computed to be 388 kJ/mol and 1.3 respectively, assuming Johnson-Mehl-Avrami model of crystallization. Another important result is that a maximum of around 70% of spherulitic-dendritic like crystal morphology can be obtained after heat treatment at 1,000 degrees C for 24 h, while a lower amount (approximately 58%) of interlocked plate like mica crystals is formed after heat treatment at 1,040 degrees C for 4 h.

Heat transfer in rotating serpentine passages with selected model orientation for smooth or skewed trip walls

NASA Technical Reports Server (NTRS)

Johnson, B. V.; Wagner, J. H.; Steuber, G. D.; Yeh, F. C.

1993-01-01

Experiments were conducted to determine the effects of model orientation as well as buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. Turbine blades have internal coolant passage surfaces at the leading and trailing edges of the airfoil with surfaces at angles which are as large as +/- 50 to 60 degrees to the axis of rotation. Most of the previously-presented, multiple-passage, rotating heat transfer experiments have focused on radial passages aligned with the axis of rotation. Results from serpentine passages with orientations 0 and 45 degrees to the axis of rotation which simulate the coolant passages for the mid chord and trailing edge regions of the rotating airfoil are compared. The experiments were conducted with rotation in both directions to simulate serpentine coolant passages with the rearward flow of coolant or with the forward flow of coolant. The experiments were conducted for passages with smooth surfaces and with 45 degree trips adjacent to airfoil surfaces for the radial portion of the serpentine passages. At a typical flow condition, the heat transfer on the leading surfaces for flow outward in the first passage with smooth walls was twice as much for the model at 45 degrees compared to the model at 0 degrees. However, the differences for the other passages and with trips were less. In addition, the effects of buoyancy and Coriolis forces on heat transfer in the rotating passage were decreased with the model at 45 degrees, compared to the results at 0 degrees. The heat transfer in the turn regions and immediately downstream of the turns in the second passage with flow inward and in the third passage with flow outward was also a function of model orientation with differences as large as 40 to 50 percent occurring between the model orientations with forward flow and rearward flow of coolant.

Numerical simulations of heat transfer distribution of a two-pass square channel with V-rib turbulator and bleed holes

NASA Astrophysics Data System (ADS)

Kumar, Sourabh; Amano, R. S.; Lucci, Jose Martinez

2013-08-01

The blade tip region in gas turbine encounters high thermal loads due to temperature difference and hence efforts for high durability and safe operations are essential. Improved and robust methods of cooling are required to downgrade heat transfer rate to turbine blades. The blade tip regions, which are exposed to high gas flow, suffers high local thermal load which are due to external tip leakage. Jet impingement, pin cooling etc. are techniques used for cooling blades. A more usual way is to use serpentine passage with 180-degree turn. In this study, numerical simulation of heat transfer distribution of a two-pass square channel with rib turbulators and bleed holes were done. Periodical rib turbulators and bleed holes were used in the channel. The ribs arrangement were 60 degree V rib, 60 degree inverted V ribs, combination of 60 degree V rib at inlet and 60 inverted V rib at outlet section and combination of Inverted V at inlet and V rib at the outlet. The results were numerically computed using Fluent with Reynolds number of 12,500 and 28,500. Turbulence models used for computations were k-ω-SST and RSM. Temperature based and shear stress based techniques were used for heat transfer distribution prediction. The results for 60 degree V rib, 60 degree inverted V ribs were compared with the experimental results for validation of the results obtained. Detailed distribution shows distinctive peaks in heat transfer around bleed holes and rib turbulator. Comparisons of the overall performance of the models with different orientation of rib turbulator are presented. It is found that due to the combination of 60 degree inverted V rib in inlet and 60 V rib in outlet with bleed holes provides better heat treatment. It is suggested that the use of rib turbulator with bleed holes provides suitable for augmenting blade cooling to achieve an optimal balance between thermal and mechanical design requirements.

Design of the thermal insulating test system for doors and windows of buildings

NASA Astrophysics Data System (ADS)

Yu, Yan; Qi, Jinqing; Xu, Yunwei; Wu, Hao; Ou, Jinping

2011-04-01

Thermal insulating properties of doors and widows are important parameter to measure the quality of windows and doors. This paper develops the thermal insulating test system of doors and windows for large temperature difference in winter in north of China according to national standards. This system is integrated with temperature measurement subsystem, temperature control subsystem, the heating power measurement subsystem, and heat transfer coefficient calculated subsystem. The temperature measurement subsystem includes temperature sensor which is implemented by sixty-four thermocouple sensors to measure the key positions of cold room and hot room, and the temperature acquisition unit which adopts Agilent 34901A data acquisition card to achieve self-compensation and accurate temperature capture. The temperature control subsystem including temperature controller and compressor system is used to control the temperature between 0 degree to 20 degree for hot room and -20 degree to 0 degree for cold room. The hot room controller uses fuzzy control algorithm to achieve accurate control of temperature and the cold room controller firstly uses compressor to achieve coarse control and then uses more accurate temperature controller unit to obtain constant temperature(-20 degree). The heating power measurement is mainly to get the heat power of hot room heating devices. After above constant temperature environment is constructed, software of the test system is developed. Using software, temperature data and heat power data can be accurately got and then the heat transfer coefficient, representing the thermal insulating properties of doors and widows, is calculated using the standard formula. Experimental results show that the test system is simple, reliable and precise. It meets the testing requirements of national standard and has a good application prospect.

Thermoregulation and heat exchange in a nonuniform thermal environment during simulated extended EVA. Extravehicular activities

NASA Technical Reports Server (NTRS)

Koscheyev, V. S.; Leon, G. R.; Hubel, A.; Nelson, E. D.; Tranchida, D.

2000-01-01

BACKGROUND: Nonuniform heating and cooling of the body, a possibility during extended duration extravehicular activities (EVA), was studied by means of a specially designed water circulating garment that independently heated or cooled the right and left sides of the body. The purpose was to assess whether there was a generalized reaction on the finger in extreme contradictory temperatures on the body surface, as a potential heat status controller. METHOD: Eight subjects, six men and two women, were studied while wearing a sagittally divided experimental garment with hands exposed in the following conditions: Stage 1 baseline--total body garment inlet water temperature at 33 degrees C; Stage 2--left side inlet water temperature heated to 45 degrees C; right side cooled to 8 degrees C; Stage 3--left side inlet water temperature cooled to 8 degrees C, right side heated to 45 degrees C. RESULTS: Temperatures on each side of the body surface as well as ear canal temperature (Tec) showed statistically significant Stage x Side interactions, demonstrating responsiveness to the thermal manipulations. Right and left finger temperatures (Tfing) were not significantly different across stages; their dynamic across time was similar. Rectal temperature (Tre) was not reactive to prevailing cold on the body surface, and therefore not informative. Subjective perception of heat and cold on the left and right sides of the body was consistent with actual temperature manipulations. CONCLUSIONS: Tec and Tre estimates of internal temperature do not provide accurate data for evaluating overall thermal status in nonuniform thermal conditions on the body surface. The use of Tfing has significant potential in providing more accurate information on thermal status and as a feedback method for more precise thermal regulation of the astronaut within the EVA space suit.

Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

PubMed

Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

2008-09-01

The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P < 0.005). Significant decreases in skin temperature, sweat rate, heart rate, and heat storage was also noted in the HI vs. the CO trials. Tolerance time in the HI exposure were longer than in the CO exposure (only 12 subjects in the CO trial endured the entire heat exposure session, as opposed to all 17 subjects in the HI group). It is concluded that hand immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods.

Thermoregulation and heat exchange in a nonuniform thermal environment during simulated extended EVA. Extravehicular activities.

PubMed

Koscheyev, V S; Leon, G R; Hubel, A; Nelson, E D; Tranchida, D

2000-06-01

Nonuniform heating and cooling of the body, a possibility during extended duration extravehicular activities (EVA), was studied by means of a specially designed water circulating garment that independently heated or cooled the right and left sides of the body. The purpose was to assess whether there was a generalized reaction on the finger in extreme contradictory temperatures on the body surface, as a potential heat status controller. Eight subjects, six men and two women, were studied while wearing a sagittally divided experimental garment with hands exposed in the following conditions: Stage 1 baseline--total body garment inlet water temperature at 33 degrees C; Stage 2--left side inlet water temperature heated to 45 degrees C; right side cooled to 8 degrees C; Stage 3--left side inlet water temperature cooled to 8 degrees C, right side heated to 45 degrees C. Temperatures on each side of the body surface as well as ear canal temperature (Tec) showed statistically significant Stage x Side interactions, demonstrating responsiveness to the thermal manipulations. Right and left finger temperatures (Tfing) were not significantly different across stages; their dynamic across time was similar. Rectal temperature (Tre) was not reactive to prevailing cold on the body surface, and therefore not informative. Subjective perception of heat and cold on the left and right sides of the body was consistent with actual temperature manipulations. Tec and Tre estimates of internal temperature do not provide accurate data for evaluating overall thermal status in nonuniform thermal conditions on the body surface. The use of Tfing has significant potential in providing more accurate information on thermal status and as a feedback method for more precise thermal regulation of the astronaut within the EVA space suit.

Application of an enthalpy balance model of the relation between growth and respiration to temperature acclimation of Eucalyptus globulus seedlings.

PubMed Central

Macfarlane, Craig; Adams, Mark A; Hansen, Lee D

2002-01-01

The enthalpy balance model of growth uses measurements of the rates of heat and CO(2) production to quantify rates of decarboxylation, oxidative phosphorylation and net anabolism. Enthalpy conversion efficiency (eta(H)) and the net rate of conservation of enthalpy in reduced biosynthetic products (R(SG)DeltaH(B)) can be calculated from metabolic heat rate (q) and CO(2) rate (R(CO2)). eta(H) is closely related to carbon conversion efficiency and the efficiency of conservation of available electrons in biosynthetic products. R(SG)DeltaH(B) and eta(H) can be used, together with biomass composition, to describe the rate and efficiency of growth of plant tissues. q is directly related to the rate of O(2) consumption and the ratio q:R(CO2) is inversely related to the respiratory quotient. We grew seedlings of Eucalyptus globulus at 16 and 28 degrees C for four to six weeks, then measured q and R(CO2) using isothermal calorimetry. Respiratory rate at a given temperature was increased by a lower growth temperature but eta(H) was unaffected. Enthalpy conversion efficiency - and, therefore, carbon conversion efficiency - decreased with increasing temperature from 15 to 35 degrees C. The ratio of oxidative phosphorylation to oxygen consumption (P/O ratio) was inferred in vivo from eta(H) and by assuming a constant ratio of growth to maintenance respiration with changing temperature. The P/O ratio decreased from 2.1 at 10-15 degrees C to less than 0.3 at 35 degrees C, suggesting that decreased efficiency was not only due to activity of the alternative oxidase pathway. In agreement with predictions from non-equilibrium thermodynamics, growth rate was maximal near 25 degrees C, where the calculated P/O ratio was about half maximum. We propose that less efficient pathways, such as the alternative oxidase pathway, are necessary to satisfy the condition of conductance matching whilst maintaining a near constant phosphorylation potential. These conditions minimize entropy production and maximize the efficiency of mitochondrial energy conversions as growing conditions change, while maintaining adequate finite rates of energy processing. PMID:12137581

Effects of early heat exposure on thermoregulatory responses and blood viscosity of broilers prior to marketing.

PubMed

Zhou, W T; Fujita, M; Ito, T; Yamamoto, S

1997-07-01

1. This study was to determine the effects of heat load early in life on thermoregulatory responses and whole blood viscosity of broilers during a subsequent exposure to high environmental temperature later in life. 2. The birds, which had been subjected to exposure to 38 degrees C for 24 h at 5-d-old, served as prior exposure group (group A). Both group A and control group B were exposed to 33 degrees C for 3 h when near marketable weight. 3. On exposure to 33 degrees C, although there were no significant differences in the increases in heat production (HP) between the two groups, abdominal temperature (Ta), temperature of external ear tract (Tee), shank skin temperature (Tss), standing-lying frequency and lying time were lower in group A than in group B. Heart rate (HR) and comb surface temperature (Tcs) did not differ but increased in both groups during exposure to 33 degrees C. Respiration rate (RR) was greater in group A. 4. Blood viscosity decreased markedly in both groups after exposure to 33 degrees C; the decrease was greater in group A. 5. These results suggest that early exposure may promote broilers' ability to cope with the subsequent heat load by altering thermoregulatory physiological responses and behavioural patterns, resulting in an alleviation of heat stress.

Symmetric miniaturized heating system for active microelectronic devices.

PubMed

McCracken, Michael; Mayer, Michael; Jourard, Isaac; Moon, Jeong-Tak; Persic, John

2010-07-01

To qualify interconnect technologies such as microelectronic fine wire bonds for mass production of integrated circuit (IC) packages, it is necessary to perform accelerated aging tests, e.g., to age a device at an elevated temperature or to subject the device to thermal cycling and measure the decrease of interconnect quality. There are downsides to using conventional ovens for this as they are relatively large and have relatively slow temperature change rates, and if electrical connections are required between monitoring equipment and the device being heated, they must be located inside the oven and may be aged by the high temperatures. Addressing these downsides, a miniaturized heating system (minioven) is presented, which can heat individual IC packages containing the interconnects to be tested. The core of this system is a piece of copper cut from a square shaped tube with high resistance heating wire looped around it. Ceramic dual in-line packages are clamped against either open end of the core. One package contains a Pt100 temperature sensor and the other package contains the device to be aged placed in symmetry to the temperature sensor. According to the temperature detected by the Pt100, a proportional-integral-derivative controller adjusts the power supplied to the heating wire. The system maintains a dynamic temperature balance with the core hot and the two symmetric sides with electrical connections to the device under test at a cooler temperature. Only the face of the package containing the device is heated, while the socket holding it remains below 75 degrees C when the oven operates at 200 degrees C. The minioven can heat packages from room temperature up to 200 degrees C in less than 5 min and maintain this temperature at 28 W power. During long term aging, a temperature of 200 degrees C was maintained for 1120 h with negligible resistance change of the heating wires after 900 h (heating wire resistance increased 0.2% over the final 220 h). The device is also subjected to 5700 thermal cycles between 55 and 195 degrees C, demonstrating reliability under thermal cycling.

Isolation of tooth pulp cells for sex chromatin studies in experimental dehydrated and cremated remains.

PubMed

Duffy, J B; Waterfield, J D; Skinner, M F

1991-03-01

In experiments designed to assess sex chromatin in artificially mummified and heated pulp tissue, a method was devised that successfully separates cells while minimizing nuclear damage. Sex chromatin (both Barr bodies and F-bodies) is shown to preserve in dehydrated human pulps up to one year. Human pulp tissue retains sex diagnostic characteristics when heated to 100 degrees C for up to 1 h. Parallel experiments on extracted teeth from young pigs reveals comparable tissue preservation. Heat penetration is retarded, however, in unextracted pig teeth in fleshed jaws such that temperatures could be raised to 300 degrees C for longer than 1 h. Heat penetration into fleshed material was further tested by the insertion of thermocouple probes to assess the temperature attained within the pulp chamber. At chamber temperatures up to 75 degrees C sex diagnosis in human pulps from extracted teeth was still possible. In outdoor incineration of fleshed pigs' heads in an open fire, 75 degrees C in the pulp chamber was reached at a fire temperature within the range 500-700 degrees C. The implications of these findings for forensic situations are described.

A microarray analysis of the effects of moderate hypothermia and rewarming on gene expression by human hepatocytes (HepG2).

PubMed

Sonna, Larry A; Kuhlmeier, Matthew M; Khatri, Purvesh; Chen, Dechang; Lilly, Craig M

2010-09-01

The gene expression changes produced by moderate hypothermia are not fully known, but appear to differ in important ways from those produced by heat shock. We examined the gene expression changes produced by moderate hypothermia and tested the hypothesis that rewarming after hypothermia approximates a heat-shock response. Six sets of human HepG2 hepatocytes were subjected to moderate hypothermia (31 degrees C for 16 h), a conventional in vitro heat shock (43 degrees C for 30 min) or control conditions (37 degrees C), then harvested immediately or allowed to recover for 3 h at 37 degrees C. Expression analysis was performed with Affymetrix U133A gene chips, using analysis of variance-based techniques. Moderate hypothermia led to distinct time-dependent expression changes, as did heat shock. Hypothermia initially caused statistically significant, greater than or equal to twofold changes in expression (relative to controls) of 409 sequences (143 increased and 266 decreased), whereas heat shock affected 71 (35 increased and 36 decreased). After 3 h of recovery, 192 sequences (83 increased, 109 decreased) were affected by hypothermia and 231 (146 increased, 85 decreased) by heat shock. Expression of many heat shock proteins was decreased by hypothermia but significantly increased after rewarming. A comparison of sequences affected by thermal stress without regard to the magnitude of change revealed that the overlap between heat and cold stress was greater after 3 h of recovery than immediately following thermal stress. Thus, while some overlap occurs (particularly after rewarming), moderate hypothermia produces extensive, time-dependent gene expression changes in HepG2 cells that differ in important ways from those induced by heat shock.

Heat-directed tumor cell fusion.

PubMed

Brade, Anthony M; Szmitko, Paul; Ngo, Duc; Liu, Fei-Fei; Klamut, Henry J

2003-03-20

In previous studies we demonstrated that a modified human HSP70b promoter (HSE.70b) directs high levels of gene expression to tumor cells after mild hyperthermia treatment in the range of 41.5-44 degrees C. This transcriptional targeting system exhibits low basal activity at 37 degrees C, is highly induced (950-fold) after mild heat treatment (43 degrees C/30 min), and returns to basal activity levels within 12-24 hours of activation. Here we describe heat-directed targeting of an activated form of the Gibbon ape leukemia virus env protein (GALV FMG) to tumor cells. GALV FMG mediates cell-cell fusion, and when expressed in tumor cells can produce bystander effects of up to 1:200. Transient transfection of a HSE70b.GALV FMG minigene caused extensive syncytia formation in HeLa and HT-1080 cells following mild heat treatment (44 degrees C/30 min). Stable transfection into HT-1080 cells produced a cell line (HG5) that exhibits massive syncytia formation and a 60% reduction in viability relative to a vector-only control (CI1) following heat treatment in vitro. Mild hyperthermia also resulted in syncytia formation, necrosis, and complete macroscopic regression of HG5 xenograft tumors grown in the footpads of mice with severe combined immunodeficiency disorders (SCID). Median survival increased from 12.5 (in heated CI1 controls) to 52 days after a single heat treatment. Heat-directed tumor cell fusion may prove to be a highly beneficial adjunct to existing cancer treatment strategies that take advantage of the synergistic interaction between mild hyperthermia and radiation or chemotherapeutic drugs.

Analysis of sensible heat exchanges from a thermal manikin.

PubMed

Quintela, Divo; Gaspar, Adélio; Borges, Carlos

2004-09-01

The present work is dedicated to the analysis of dry heat exchanges as measured by a thermal manikin placed in still air. We believe that the understanding of some fundamental aspects governing fluid flow and heat transfer around three-dimensional bodies such as human beings deserves appropriate attention. This should be of great significance for improving physiological models concerned with thermal exposures. The potential interest of such work can be directed towards quite distinct targets such as working conditions, sports, the military, or healthcare personnel and patients. In the present study, we made use of a climate chamber and an articulated thermal manikin of the Pernille type, with 16 body parts. The most common occidental postures (standing, sitting and lying) were studied. In order to separate heat losses due to radiation and convection, the radiative heat losses of the manikin were significantly reduced by means of a shiny aluminium coating, which was carefully applied to the artificial skin. The air temperature within the test chamber was varied between 13 degrees C and 29 degrees C. The corresponding mean differences between the skin and the operative temperatures changed from 3.8 degrees C up to 15.8 degrees C. The whole-body heat transfer coefficients by radiation and convection for both standing and sitting postures are in good agreement with those in the published literature. The lying posture appears to be more efficient for losing heat by convection. This is confirmed when the heat losses of each individual part are considered. The proposed correlations for the whole body suggest that natural convection is mainly laminar.

Boll weevil (Coleoptera: Curculionidae) response to and volatilization rates of grandlure when combined with varying doses of eugenol in the extended-life pheromone lure.

PubMed

Armstrong, J S

2010-04-01

Boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), trapping and pheromone quantitative analysis of extended-life pheromone lures manufactured with 0, 10, 20, and 30 mg of eugenol was conducted in the Rio Grande Valley of Texas under spring and summer conditions. Boll weevils responded positively to eugenol on one of 12 trapping weeks when densities were high, but when densities were low (<2 weevils trap(-1) wk(-1)), there were no significant differences in captures for any dosage of eugenol offered in a standard boll weevil trap. Weekly grandlure volatilization did not differ by eugenol dose but was significantly different when evaluated over three different trapping periods and by week within trapping period due to differences in ambient temperature. The amount of grandlure that remained after 4 wk in moderate temperatures of spring was 13.1 +/- 0.19 mg (55.7% of original 25 mg of content) compared with 5.5 +/- 0.15 mg remaining (22.8% of original 25 mg content) after for 4 wk in summer heat. Weekly volatilization of grandlure for the summer trapping period was 9.8 +/- 0.32 mg for the first week, declining steadily to 1.0 +/- 0.09 mg by the fourth week of age. The data indicate that at high summer temperatures >30 degrees C, accumulative grandlure loss per week may be too high, leaving too little residual grandlure to effectively attract boll weevils at the end of 3 wk of trapping. Eugenol plays no role in reserving or encouraging the release of grandlure, or in increasing boll weevil captures when boll weevil densities are low.

Thermoregulation in complex situations: combined heat exposure, infectious fever and water deprivation.

PubMed

Blatteis, C M

2000-05-01

Heat exposure, infectious fever and water deprivation are stressors that, individually, produce disturbances in more than one regulated system, calling for diverse compensatory responses. A potential conflict is created when these stimuli are combined and impose concurrent stressful loads on the body because the homeostatic defenses mobilized against one are also partly needed against the other stressors. To learn how the competing demands of combined stressors for shared regulatory systems are met, rabbits were exposed to 32 degrees C and 37 degrees C (heat), administered lipopolysaccharide (Salmonella enteritidis LPS, 2 lg/kg, i.v.) in temperatures of 22 degrees C or 27 degrees C, or water-deprived for 1 or 2 days in 22 degrees C or 27 degrees C, in separate experiments. The corresponding controls were exposed to 22 degrees C or 27 degrees C, administered pyrogen-free saline i.v. in 22 degrees C or 27 degrees C, or normally hydrated in 22 degrees C or 27 degrees C. In subsequent experiments, two or all three of these treatments were applied concurrently. Core and ear skin temperatures and respiratory rates were monitored continuously. The results indicated that the concomitant needs of moderate heat exposure, fever and 1 day of water deprivation were generally met by the regulatory systems involved, but different patterns of thermoeffector activities were evoked and the eventual body temperature changes produced were different under each condition. However, when the test conditions were severe, their combined needs were not met adequately and the eventual compensatory response depended not only on the particular stimulus intensity, but also on the immediate importance for survival of the functions being defended. Thus, dehydration was the most dangerous factor to the physiological integrity of the animals. In sum, conflicting physiological stimuli appear to result in responses that are different from the responses to a single perturbation, the eventual output representing the resultant of the inputs rather than a singular output dictated by one dominant drive to the exclusion of the others.

Heat resistance of Bacillus cereus spores: effects of milk constituents and stabilizing additives.

PubMed

Mazas, M; López, M; Martínez, S; Bernardo, A; Martin, R

1999-04-01

Heat resistance of Bacillus cereus spores (ATCC 7004, 4342, and 9818) heated in different types of milk (skim, whole, and concentrated skim milk), skim milk containing stabilizing additives (sodium citrate, monopotassium phosphate, or disodium phosphate, 0.1%), and cream was investigated. Thermal resistance experiments were performed at temperatures within the range of 92 to 115 degrees C under continuous monitoring of pH. For strain 4342 no significant differences (P < 0.05) in D values were detected in any case. For strains 7004 and 9818 higher D values of about 20% were obtained in whole and concentrated skim milk than those calculated in skim milk. From all stabilizing additives tested, only sodium citrate and sodium phosphate increased the heat resistance for strain 9818. However, when the menstruum pH was measured at the treatment temperature, different pH values were found between the heating media. The differences in heat resistance observed could be due to a pH effect rather than to the difference in the substrates in which spores were heated. In contrast, when cream (fat content 20%) was used, lower D values were obtained, especially for strains 7004 and 9818. z values were not significantly modified by the milk composition, with an average z value of 7.95+/-0.20 degrees C for strain 7004, 7.88+/-0.10 degrees C for strain 4342, and 9.13+/-0.16 degrees C for strain 9818.

Transscleral thermotherapy with laser-induced and conductive heating in hamster Greene melanoma.

PubMed

Rem, Alex I; Oosterhuis, Jendo A; Keunen, Jan E E; Journée-De Korver, Hanneke G

2004-10-01

The purpose of this study was to investigate the cytotoxic effect of heat as induced by transscleral thermotherapy (TSTT), which may be of interest in the treatment of patients with choroidal melanoma. The aim of TSTT is to heat both the sclera and the tumor up to a cytotoxic temperature of about 60 degrees C. TSTT was performed in hamsters with subcutaneously implanted Greene melanoma covered by a specimen of human donor sclera of thickness 0.5, 0.7 or 0.9 mm. A newly developed applicator, which combines conductive episcleral heating at 60 degrees C with laser-induced heating, was used at laser powers ranging from 500 to 1500 mW delivered by an 810 nm diode laser, beam diameter 3 mm, and exposure time 1 min. Temperatures were measured at the scleral surface and at the sclera-tumor interface. The extent of tumor necrosis was examined by light microscopy and the sclera was examined by polarized light microscopy. Maximal depth of tumor necrosis without scleral damage was 4.4 (SD 1.5) mm. The temperature at the scleral surface after TSTT was 58.8 (SD 2.4) degrees C. The temperature at the sclera-tumor interface ranged from 56.4 (SD 3.7) degrees C at 500 mW to 65.3 (SD 4.4) degrees C at 1250 mW laser power. Structural changes to the scleral collagen started to develop at 1250 mW. TSTT with combined laser-induced and conductive heating caused cytotoxic temperatures in the tumor and the sclera, which were well tolerated by the scleral collagen.

Thermal treatment for increasing magnetostrictive response of rare earth-iron alloy rods

DOEpatents

Verhoeven, John D.; McMasters, O. D.

1989-07-18

Magnetostrictive rods formed from rare earth-iron alloys are subjected to a short time heat treatment to increase their Magnetostrictive response under compression. The heat treatment is preferably carried out at a temperature of from 900.degree. to 1000.degree. C. for 20 minutes to six hours.

Healing Voids In Interconnections In Integrated Circuits

NASA Technical Reports Server (NTRS)

Cuddihy, Edward F.; Lawton, Russell A.; Gavin, Thomas

1989-01-01

Unusual heat treatment heals voids in aluminum interconnections on integrated circuits (IC's). Treatment consists of heating IC to temperature between 200 degrees C and 400 degrees C, holding it at that temperature, and then plunging IC immediately into liquid nitrogen. Typical holding time at evaluated temperature is 30 minutes.

Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger.

PubMed

Ma, Y; Barbano, D M

2003-12-01

Raw skim milk, with or without added CO2, was heated, held, and cooled in a small pilot-scale tubular heat exchanger (372 ml/min). The experiment was replicated twice, and, for each replication, milk was first carbonated at 0 to 1 degree C to contain 0 (control), 600, 1200, 1800, and 2400 ppm added CO2 using a continuous carbonation unit. After storage at 0 to 1 degree C, portions of milk at each CO2 concentration were heated to 40, 56, 72, and 80 degrees C, held at the desired temperature for 30 s (except 80 degrees C, holding 20 s) and cooled to 0 to 1 degree C. At each temperature, five pressures were applied: 69, 138, 207, 276, and 345 kPa. Pressure was controlled with a needle valve at the heat exchanger exit. Both the pressure gauge and pH probe were inline at the end of the holding section. Milk pH during heating depended on CO2 concentration, temperature, and pressure. During heating of milk without added CO2, pH decreased linearly as a function of increasing temperature but was independent of pressure. In general, the pH of milk with added CO2 decreased with increasing CO2 concentration and pressure. For milk with added CO2, at a fixed CO2 concentration, the effect of pressure on pH decrease was greater at a higher temperature. At a fixed temperature, the effect of pressure on pH decrease was greater for milk with a higher CO2 concentration. Thermal death of bacteria during pasteurization of milk without added CO2 is probably due not only to temperature but also to the decrease in pH that occurs during the process. Increasing milk CO2 concentration and pressure decreases the milk pH even further during heating and may further enhance the microbial killing power of pasteurization.

Effects of growth temperature and strictly anaerobic recovery on the survival of Listeria monocytogenes during pasteurization.

PubMed Central

Knabel, S J; Walker, H W; Hartman, P A; Mendonca, A F

1990-01-01

Listeria monocytogenes F5069 was suspended in either Trypticase soy broth-0.6% yeast extract (TSBYE) or sterile, whole milk and heated at 62.8 degrees C in sealed thermal death time tubes. Severely heat-injured cells were recovered in TSBYE within sealed thermal death time tubes because of the formation of reduced conditions in the depths of the TSBYE. Also, the use of strictly anaerobic Hungate techniques significantly increased recovery in TSBYE containing 1.5% agar compared with aerobically incubated controls. The exogenous addition of catalase, but not superoxide dismutase, slightly increased the recovery of heat-injured cells in TSBYE containing 1.5% agar incubated aerobically. Growth of cells at 43 degrees C caused a greater increase in heat resistance as compared with cells heat shocked at 43 degrees C or cells grown at lower temperatures. Growth of L. monocytogenes at 43 degrees C and enumeration by the use of strictly anaerobic Hungate techniques resulted in D62.8 degrees C values that were at least sixfold greater than those previously obtained by using cells grown at 37 degrees C and aerobic plating. Results indicate that, under the conditions of the present study, high levels of L. monocytogenes would survive the minimum low-temperature, long-time treatment required by the U.S. Food and Drug Administration for pasteurizing milk. The possible survival of low levels of L. monocytogenes during high-temperature, short-time pasteurization and enumeration of injured cells by recovery on selective media under strictly anaerobic conditions are discussed. PMID:2106284

Variation of optical properties of gel-derived VO2 thin films with temperature

NASA Astrophysics Data System (ADS)

Hou, Lisong; Lu, Song W.; Gan, Fuxi

1991-11-01

VO2 thin films are prepared on three kinds of substrates by the sol-gel dip-coating method followed by heat treatment under vacuum conditions. The IR and UV-visible spectra of the films are studied during heating and cooling between room temperature and 100 degree(s)C. The experimental results show that the films exhibit thermally-induced reversible phase transition and, as a result, the maximum changes in transmittance and reflectivity are 58% and 25%, respectively, in the case of vacuum heat treatment at 400 degree(s)C and silica glass substrates. The refractive index n decreases and the extinction coefficient k increases when heating these films from room temperature to 100 degree(s)C, and vice versa. The reasons why the optical constants and IR absorption spectra change so remarkably are discussed.

[Experimental investigation on emission characteristic of NOx during micropulverized coal oxidation].

PubMed

Jiang, Xiu-Min; Wei, Li-Hong; Huang, Xiang-Yong; Zhang, Chao-Qun

2008-03-01

The combustion experiments of HG micronized coal have been conducted by combining DTG and GC-MS. The effects on NOx emission caused by particle size, oxygen concentration and heating rate were analyzed. The results show that under combustion condition that oxygen concentration is 20%, NOx precipitations of HG coal in difference sizes are single-peaked courses. Particle size impacts NOx emission from coal combustion significantly. Micro-pulverized coal reduces NOx emission. Under heating condition with 5 degrees C/min, 10 degrees C/min and 20 degrees C/min, precipitation of NO and NO2 is increased with heating rate rising, and temperature parallelized with maximum NO precipitation rate is increased with heating rate rising as well. With increasing of oxygen concentration in combustion, NOx precipitation increases correspondingly, and temperature parallelized with maximum NOx precipitation rate is reduced.

[Effect of heat treatment on the structure of a Cu-Zn-Al-Ni system dental alloy].

PubMed

Guastaldi, A C; Adorno, A T; Beatrice, C R; Mondelli, J; Ishikiriama, A; Lacefield, W

1990-01-01

This article characterizes the structural phases present in the copper-based metallic alloy system "Cu-Zn-Al-Ni" developed for dental use, and relates those phases to other properties. The characterization was obtained after casting (using the lost wax process), and after heat treatment. In order to obtain better corrosion resistance by changing the microstructure, the castings were submitted to 30, 45 and 60 minutes of heat treatment at the following temperatures: 750 degrees C, 800 degrees C, and 850 degrees C. The various phases were analyzed using X-ray diffraction and scanning electron microscopy (SEM). The results after heat treatment showed a phase (probably Cu3Al), that could be responsible for the improvement in the alloy's resistance to corrosion as compared to the as-cast structure.

Forced heat loss from body surface reduces heat flow to body surface.

PubMed

Berman, A

2010-01-01

Heat stress is commonly relieved by forced evaporation from body surfaces. The mode of heat stress relief by heat extraction from the periphery is not clear, although it reduces rectal temperature. Radiant surface temperature (Ts) of the right half of the body surface was examined by thermovision in 4 lactating Holstein cows (30 kg of milk/d) during 7 repeated cycles of forced evaporation created by 30s of wetting followed by 4.5 min of forced airflow. Wetting was performed by an array of sprinklers (0.76 m(3)/h), and forced airflow (>3m/s velocity) over the right side of the body surface was produced by fans mounted at a height of 3m above the ground. Sprinkling wetted the hind legs, rump, and chest, but not the lower abdomen side, front legs, or neck. The animals were maintained in shade at an air temperature of 28 degrees C and relative humidity of 47%. Coat thickness was 1 to 2mm, so Ts closely represented skin temperature. Mean Ts of 5 x 20cm areas on the upper and lower hind and front legs, rump, chest, abdomen side, and neck were obtained by converting to temperature their respective gray intensity in single frames obtained at 10-s intervals. Little change occurred in Ts during the first wetting (0.1+/-0.6 degrees C), but it decreased rapidly thereafter (1.6+/-0.6 degrees C in the fifth wetting). The Ts also decreased, to a smaller extent, in areas that remained dry (0.7+/-1.0 degrees C). In all body sites, a plateau in Ts was reached by 2 min after wetting. The difference between dry and wet areas in the first cooling cycle was approximately 1.2 degrees C. The Ts of different body areas decreased during consecutive cooling cycles and reached a plateau by 3 cooling cycles in dry sites (front leg, neck, abdomen side), by 5 cooling cycles in the hind leg, and 7 cooling cycles in the rump and chest. The reduction in mean Ts produced by 7 cycles was 4.0 to 6.0 degrees C in wetted areas and 1.6 to 3.7 degrees C in sites that were not wetted. Initial rectal temperature was 38.9+/-0.1 degrees C; it remained unchanged during first 5 cooling cycles, decreased by 0.1 degrees C after 7 cooling cycles, and decreased to 38.4+/-0.06 degrees C after 8 to 10 cooling cycles, with no additional subsequent decrease. The concomitant reduction in Ts in dry and wet areas suggests an immediate vasoconstrictor response associated with heat extraction and later development of a cooler body shell. The reduction in rectal temperature represents a response involving transfer of heat from the body core to the body shell. This response mode requires consideration in settings of heat stress relief. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of wearing aircrew protective clothing on physiological and cognitive responses under various ambient conditions.

PubMed

Faerevik, Hilde; Reinertsen, Randi Eidsmo

2003-06-20

Heat stress can be a significant problem for pilots wearing protective clothing during flights, because they provide extra insulation which prevents evaporative heat loss. Heat stress can influence human cognitive activity, which might be critical in the flying situation, requiring efficient and error-free performance. This study investigated the effect of wearing protective clothing under various ambient conditions on physiological and cognitive performance. On several occasions, eight subjects were exposed for 3 h to three different environmental conditions; 0 degrees C at 80% RH, 23 degrees C at 63% RH and 40 degrees C at 19% RH. The subjects were equipped with thermistors, dressed as they normally do for flights (including helmet, two layers of underwear and an uninsulated survival suit). During three separate exposures the subjects carried out two cognitive performance tests (Vigilance test and DG test). Performance was scored as correct, incorrect, missed reaction and reaction time. Skin temperature, deep body temperature, heart rate, oxygen consumption, temperature and humidity inside the clothing, sweat loss, subjective sensation of temperature and thermal comfort were measured. Rises in rectal temperature, skin temperature, heart rate and body water loss indicated a high level of heat stress in the 40 degrees C ambient temperature condition in comparison with 0 degrees C and 23 degrees C. Performance of the DG test was unaffected by ambient temperature. However, the number of incorrect reactions in the Vigilance test was significantly higher at 40 degrees C than at 23 degrees C (p = 0.006) or 0 degrees C (p = 0.03). The effect on Vigilance performance correlated with changes in deep-body temperature, and this is in accordance with earlier studies that have demonstrated that cognitive performance is virtually unaffected unless environmental conditions are sufficient to change deep body temperature.

Heat resistance of Escherichia coli O157:H7 in apple juice.

PubMed

Splittstoesser, D F; McLellan, M R; Churey, J J

1996-03-01

The objective was to determine the effect of cider composition on the heat resistance of Escherichia coli O157:H7. The average D52 value in a model Empire apple juice was 18 min with a z value of 4.8 degrees C. Increasing the Brix from 11.8 to 16.5 degrees had no effect on thermal resistance, while increasing L-malic acid from 0.2 to 0.8%, or reducing the pH from 4.4 to 3.6 sensitized the cells to heat. The greatest effect on heat resistance was afforded by the preservatives benzoic and sorbic acids: D50 values in ciders containing 1,000 mg/l were 5.2 min in the presence of sorbic acid and only 0.64 min in the presence of benzoic acid. Commercial apple juice concentrates yielded lower numbers of survivors than single-strength juices even though their higher sugar concentrations of about 46 degrees Brix increased heat resistance.

Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion

DOEpatents

Steeves, Arthur F.; Bibb, Albert E.

1984-01-01

A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprising heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cool the alloy body, and heat the cooled body to a temperature between 1100.degree. to 1500.degree. F. for about 1 to 30 hours.

Impaired glucose utilization in man during acute exposure to environmental heat.

PubMed

Tatár, P; Vigas, M; Jurcovicová, J; Jezová, D; Strec, V; Palát, M

1985-12-01

In 6 healthy males the oral glucose tolerance test (OGTT) was performed after the administration of 100 g glucose during the hyperthermic Finnish sauna bath (85 degrees C) of 30 min duration. The lowered insulin response (P less than 0.001) to glucose challenge during heating and the subsequent prolonged hyperglycemia (P less than 0.001) after heating were observed, when compared to OGTT under thermoneutral conditions (23 degrees C). It is suggested that the heat-induced decrease in visceral blood flow and stimulation of sympathoadrenomedullary and pituitary activity may be responsible for this effect.

Design and construction of Thermoelectric Footwear Heating System for illness feet.

PubMed

Işik, Hakan

2005-12-01

In this study, a Thermoelectric Footwear Heating System is developed to use in cold weather conditions. The temperature is controlled by an analog electronic control system. Thermoelectric module is used to heat the bottom of the foot. A negative temperature coefficient (NTC) temperature sensor is used to sense the temperature and the temperature is controlled by an electronic circuit proportionally. A 3.5 V, 5000 mAh rechargeable battery is used as the power source. The temperature range of the system is between +15 degrees C and +50 degrees C. Developed footwear heating system is tested against various temperature conditions, and offer better results in the case of heating the illness feet.

Influence of heat and vibration on the movement of the northern fowl mite (Acari: Macronyssidae).

PubMed

Owen, Jeb P; Mullens, Bradley A

2004-09-01

Heat and vibration are common host-generated cues that ectoparasites use to orient to hosts. Three experiments evaluated effects of heat and vibration on the movement of northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Individual arrested mites in an isolation chamber always initiated movement (walking) after substrate vibration (7.8-min walking duration), but only initiated movement 50% of the time (2.8-min walking duration) upon exposure to a 3 degrees C heat fluctuation. Heat fluctuation in combination with vibration extended the period of activity by approximately 50% (11.6-min walking duration) compared with activity initiated by vibration alone. Mites with longer time off-host moved for shorter durations. In a choice test, individual mites consistently moved closer to a 35 degrees C heat source 1 or 6 mm away, but not to a heat source 11 mm away. In a circular arena, mites were able to orient accurately to a 35 degrees C heat source and reached the arena edge almost 4 times faster (11.2 s) than mites without a heat source (41.2 s). These results suggest that northern fowl mite is capable of directed thermo-orientation, as well as modulation of activity depending on the type of sensory information perceived. The adaptive significance of this orientation for a "permanent" ectoparasite is discussed.

Antioxidative activity of microencapsulated gamma-oryzanol on high cholesterol-fed rats.

PubMed

Suh, Mun-Hee; Yoo, Sang-Ho; Chang, Pahn-Shick; Lee, Hyeon Gyu

2005-12-14

The effectiveness of microencapsulated gamma-oryzanol (M-gamma-OZ) was evaluated as an antioxidant in Sprague-Dawley rats. Lard containing 100 ppm of gamma-OZ (HCD III) or 100 ppm of M-gamma-OZ (HCD IV) was heated in an oven for 7 days, and the heat-treated lard as an ingredient in a high cholesterol diet (HCD) formulation was tested for analyzing in vivo cholesterol and lipid profiles. The HCDs containing fresh lard (HCD I) and heat-treated lard (HCD II) were fed to the rats for 4 weeks as control groups A and B, respectively, in this experiment. The liver thiobarbituric acid reactive substances values of group C (fed with HCD III) and group D (with HCD IV) were significantly lower (p < 0.05) than that of negative control, group B. One of the cholesterol oxidation products, 7-ketocholesterol, was not detected from group D, indicating that microencapsulation preserved antioxidative activity effectively. The levels of serum total cholesterol and lipoproteins, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein were also affected by heat-induced lipid oxidation.The M-gamma-OZ evidently decreased LDL-cholesterol content and increased HDL-cholesterol in blood samples of tested rats. These results suggested that the M-gamma-OZ was not only effective in inhibiting the hypercholesterolemia of serum and liver but also reduced the oxidation degree of lipids and cholesterol. Therefore, this microencapsulation can be a good potential technique to protect the antioxidant activity of gamma-OZ from heat-induced lipid oxidation.

Two-stage hydrothermal processing of wheat (Triticum aestivum) bran for the production of feruloylated Arabinoxylooligosaccharides.

PubMed

Rose, Devin J; Inglett, George E

2010-05-26

Two-stage hydrothermal processing was employed to obtain feruloylated arabinoxylooligosaccharides (AXOS) from wheat bran. First, wheat bran in water (10% w/w solids) was heated to 130 degrees C, releasing 36.3% of total solids, 70.3% of starch, and 6.06% of pentose sugars. Wheat bran was then heated to 170-220 degrees C. Heating to 200 and 210 degrees C released the most AXOS (70% of the insoluble arabinoxylan) and esterified ferulate (30% of the initial ferulic acid). Treatment of 200 degrees C retained a higher proportion of high molecular weight (>1,338) compounds than 210 degrees C and was the preferred treatment temperature because autohydrolysate liquors contained lower concentrations of many contaminants. Purification of this autohydrolysate liquor with ethyl acetate extraction, vacuum concentration, and ion exchange resulted in a product containing 32.0% AXOS and 4.77% esterified ferulate, accompanied by 36.0% other oligosaccharides and free sugars, with an antioxidant activity of 29.7 micromol Trolox equivalents/g dry matter.

Fabrication of heterojunction solar cells by improved tin oxide deposition on insulating layer

DOEpatents

Feng, Tom; Ghosh, Amal K.

1980-01-01

Highly efficient tin oxide-silicon heterojunction solar cells are prepared by heating a silicon substrate, having an insulating layer thereon, to provide a substrate temperature in the range of about 300.degree. C. to about 400.degree. C. and thereafter spraying the so-heated substrate with a solution of tin tetrachloride in a organic ester boiling below about 250.degree. C. Preferably the insulating layer is naturally grown silicon oxide layer.

Preparation and properties of porous microspheres made from borate glass.

PubMed

Conzone, Samuel D; Day, Delbert E

2009-02-01

Dysprosium lithium-borate glass microspheres and particles, ranging from 45 to 150 microm in diameter, were reacted with a 0.25 M phosphate solution at 37 degrees C, whose pH was either 3 or 8.8. The glass reacted nonuniformly and was converted into a porous, amorphous, hydrated, dysprosium phosphate reaction product. The amorphous product had the same volume and shape (pseudomorphic) as the unreacted glass, and could be dried without cracking. After heating at 300 degrees C for 1 h, the amorphous reaction product had a specific surface area of approximately 200 m(2)/g, a pore size of approximately 30 nm, and nominal crushing strength of approximately 10 MPa. When the reaction product was heated to 600 degrees C for 15 min, the specific surface area decreased to approximately 90 m(2)/g and the nominal crushing strength increased to 35 MPa. Heating above 615 degrees C converted the amorphous dysprosium phosphate product into crystalline DyPO(4), which contained open porosity until heated above 800 degrees C for 15 min. Highly porous materials of different chemical composition can be prepared by chemically reacting a borate-based glass with an aqueous solution at low-temperature (<100 degrees C). These highly porous materials are easy to process, and are considered candidates for controlled drug delivery, catalysis, chromatographic separation, filtration, and as bioactive materials.

Digestive state influences the heart rate hysteresis and rates of heat exchange in the varanid lizard Varanus rosenbergi.

PubMed

Clark, T D; Butler, P J; Frappell, P B

2005-06-01

To maximize the period where body temperature (Tb) exceeds ambient temperature (Ta), many reptiles have been reported to regulate heart rate (fH) and peripheral blood flow so that the rate of heat gain in a warming environment occurs more rapidly than the rate of heat loss in a cooling environment. It may be hypothesized that the rate of cooling, particularly at relatively cool Tbs, would be further reduced during postprandial periods when specific dynamic action (SDA) increases endogenous heat production (i.e. the heat increment of feeding). Furthermore, it may also be hypothesized that the increased perfusion of the gastrointestinal organs that occurs during digestion may limit peripheral blood flow and thus compromise the rate of heating. Finally, if the changes in fh are solely for the purpose of thermoregulation, there should be no associated changes in energy demand and, consequently, no hysteresis in the rate of oxygen consumption (V(O2)). To test these hypotheses, seven individual Varanus rosenbergi were heated and cooled between 19 degrees C and 35 degrees C following at least 8 days fasting and then approximately 25 h after consumption of a meal (mean 10% of fasted body mass). For a given Tb between the range of 19-35 degrees C, fh of fasting lizards was higher during heating than during cooling. Postprandial lizards also displayed a hysteresis in fh, although the magnitude was reduced in comparison with that of fasting lizards as a result of a higher fh during cooling in postprandial animals. Both for fasting and postprandial lizards, there was no hysteresis in V(O2) at any Tb throughout the range although, as a result of SDA, postprandial animals displayed a significantly higher V(O2) than fasting animals both during heating and during cooling at Tbs above 24 degrees C. The values of fh during heating at a given Tb were the same for fasting and postprandial animals, which, in combination with a slower rate of heating in postprandial animals, suggests that a prioritization of blood flow to the gastrointestinal organs during digestion is occurring at the expense of higher rates of heating. Additionally, postprandial lizards took longer to cool at Tbs below 23 degrees C, suggesting that the endogenous heat produced during digestion temporarily enhances thermoregulatory ability at lower temperatures, which would presumably assist V. rosenbergi during cooler periods in the natural environment by augmenting temperature-dependent physiological processes.

Response properties of mechanoreceptors and nociceptors in mouse glabrous skin: an in vivo study.

PubMed

Cain, D M; Khasabov, S G; Simone, D A

2001-04-01

The increasing use of transgenic mice for the study of pain mechanisms necessitates comprehensive understanding of the murine somatosensory system. Using an in vivo mouse preparation, we studied response properties of tibial nerve afferent fibers innervating glabrous skin. Recordings were obtained from 225 fibers identified by mechanical stimulation of the skin. Of these, 106 were classed as A beta mechanoreceptors, 51 as A delta fibers, and 68 as C fibers. A beta mechanoreceptors had a mean conduction velocity of 22.2 +/- 0.7 (SE) m/s (13.8--40.0 m/s) and a median mechanical threshold of 2.1 mN (0.4--56.6 mN) and were subclassed as rapidly adapting (RA, n = 75) or slowly adapting (SA, n = 31) based on responses to constant force mechanical stimuli. Conduction velocities ranged from 1.4 to 13.6 m/s (mean 7.1 +/- 0.6 m/s) for A delta fibers and 0.21 to 1.3 m/s (0.7 +/- 0.1 m/s) for C fibers. Median mechanical thresholds were 10.4 and 24.4 mN for A delta and C fibers, respectively. Responses of A delta and C fibers evoked by heat (35--51 degrees C) and by cold (28 to -12 degrees C) stimuli were determined. Mean response thresholds of A delta fibers were 42.0 +/- 3.1 degrees C for heat and 7.6 +/- 3.8 degrees C for cold, whereas mean response thresholds of C fibers were 40.3 +/- 0.4 degrees C for heat and 10.1 +/- 1.9 degrees C for cold. Responses evoked by heat and cold stimuli increased monotonically with stimulus intensity. Although only 12% of tested A delta fibers were heat sensitive, 50% responded to cold. Only one A delta nociceptor responded to both heat and cold stimuli. In addition, 40% of A delta fibers were only mechanosensitive since they responded neither to heat nor to cold stimuli. Thermal stimuli evoked responses from the majority of C fibers: 82% were heat sensitive, while 77% of C fibers were excited by cold, and 68% were excited by both heat and cold stimuli. Only 11% of C fibers were insensitive to heat and/or cold. This in vivo study provides an analysis of mouse primary afferent fibers innervating glabrous skin including new information on encoding of noxious thermal stimuli within the peripheral somatosensory system of the mouse. These results will be useful for future comparative studies with transgenic mice.

Hormetic protection of Drosophila melanogaster middle-aged male flies from heat stress by mildly stressing them at young age

NASA Astrophysics Data System (ADS)

Bourg, Éric

2005-06-01

Previous studies have shown that exposing flies to hypergravity (3g or 5g) for the first 2 weeks of adult life slightly increases longevity of male flies and survival time at 37°C for both sexes, and delays an age-linked behavioral change. The present experiment tested whether the hypergravity could also protect flies from four successive deleterious non-lethal heat shocks at 4 and 5 weeks of age. Males that lived in hypergravity for the first 2 weeks of adult life lived slightly longer (ca. +15% or 1.2 day) after heat shocks (30 min or 45 min at 37°C) than flies that always lived at 1g, but this positive effect of hypergravity was not observed in females. Therefore, hypergravity exposure at young age can help the male flies recovering from a heat shock at older ages.

Two-step sulfonation process for the conversion of polymer fibers to carbon fibers

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

Barton, Bryan E.; Patton, Jasson T.; Hukkanen, Eric J.

Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 501-3000.degree. C. Carbon fibers prepared according to these methods are also disclosed herein.

Heating tar sands formations to visbreaking temperatures

DOEpatents

Karanikas, John Michael [Houston, TX; Colmenares, Tulio Rafael [Houston, TX; Zhang, Etuan [Houston, TX; Marino, Marian [Houston, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Beer, Gary Lee [Houston, TX; Dombrowski, Robert James [Houston, TX; Jaiswal, Namit [Houston, TX

2009-12-22

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

Preservation of raw milk with CO2. Sensory evaluation of heat-processed milks.

PubMed

Amigo, L; Olano, A; Calvo, M M

1995-04-01

The effect of CO2 on the growth of psychrotrophic milk spoilage organisms was studied, both in raw fresh milk and in pure cultures of three species of Pseudomonas growing in sterilised milk. Changes of sensory properties of CO2-treated samples after heat treatment were also analysed. Inhibition of psychrotrophic growth at 7 degrees C in milk treated with CO2 to a pH 6.2 or 6.0 was impaired by a gradual reduction of the CO2 content during storage. Growth inhibition was considerably improved by pH adjustment at 24-h intervals. Sensory analysis showed significant differences between non-acidified and acidified samples after heat treatment at 75 degrees C for 20 s or 110 degrees C for 5 min. No sensory differences were found between non-acidified and acidified milks degassed before heat treatment.

Air temperature recordings in infant incubators.

PubMed Central

Aynsley-Green, A; Roberton, N R; Rolfe, P

1975-01-01

Air temperatures were continuously recorded inside four incubators with proportional heating control and six incubators with on/off heating cycles, during routine use. The air temperatures in the former were constant throughout, with a gradient between the roof and above-mattress air temperature not exceeding 1 degree C. In contrast, the recordings from the latter models showed a regular cyclical oscillation, the duration of the cycle varying from 14 to 44 minutes. Each incubator had a characteristic profile. The roof air temperature could vary by as much as 7-1 degrees C and the above-mattress air temperature by as much as 2-6 degrees C during the cycle. The oscillation persisted in the air temperatures recorded inside an open-ended hemicylindrical heat shield when used inside these incubators, but was markedly reduced inside a closed-ended heat shield, Carbon dioxide concentration did not increase significantly inside the latter. Images FIG. 1 FIG. 2 PMID:1147654

Respiratory illness caused by overheating of polyvinyl chloride.

PubMed Central

Froneberg, B; Johnson, P L; Landrigan, P J

1982-01-01

On 9 August 1979, 62 (30.8%) of 201 workers and one of 60 management personnel in a polyvinyl chloride (PVC) fabricating plant developed acute upper and lower respiratory irritation, headache, nausea, and fainting. All were taken to hospital; none died. Sixty of the patients were women. Interviews two weeks later with 57 affected and 14 unaffected workers disclosed that illness had followed exposure to fumes from an overheated (362 degrees C) PVC extruding machine. Fumes were emitted from 1100 until 1150; cases occurred from 1100 until late afternoon. All workers who became ill worked west of the overheated extruder, and the affected manager had visited that area. The earliest cases occurred closest to the machine, and incidence decreased (from 53.3% to 15.4%) with distance westward. This pattern was consistent with plant ventilation. Incidence rates in men and women did not differ (p greater than 0.1). At two and 14 weeks, pulmonary function testing of workers with persistent pulmonary symptoms showed abnormalities in 13 of 16 and in 9 of 11 respectively; the group with persistent symptoms contained an excess of non-smokers and of those with previous respiratory illnesses. One kilogram of PVC heated to 300 degrees C releases an estimated 12.9 g of hydrochloric acid (HCl) and 4.9 g of carbon monoxide (CO). We attributed the outbreak to exposure to toxic HCl and CO and rejected the hypothesis of mass psychogenic illness. PMID:7093150

Temperature and deactivation of microbial faecal indicators during small scale co-composting of faecal matter.

PubMed

Germer, Jörn; Boh, Michael Yongha; Schoeffler, Marie; Amoah, Philip

2010-02-01

Small scale co-composting of faecal matter from dry toilet systems with shredded plant material and food waste was investigated in respect to heat development and deactivation of faecal indicators under tropical semiarid conditions. Open (uncovered) co-composting of faecal matter with shredded plant material alone did not generate temperatures high enough (<55 degrees C) to reduce the indicators sufficiently. The addition of food waste and confinement in chambers, built of concrete bricks and wooden boards, improved the composting process significantly. Under these conditions peak temperatures of up to 70 degrees C were achieved and temperatures above 55 degrees C were maintained over 2 weeks. This temperature and time is sufficient to comply with international composting regulations. The reduction of Escherichia coli, Enterococcus faecalis and Salmonella senftenberg in test containment systems placed in the core of the compost piles was very efficient, exceeding 5log10-units in all cases, but recolonisation from the cooler outer layers appeared to interfere with the sanitisation efficiency of the substrate itself. The addition of a stabilisation period by extending the composting process to over 4 months ensured that the load of E. coli was reduced to less than 10(3)cfu(-g) and salmonella were undetectable.

Retardation of brain growth of guinea pigs by hyperthermia: effect of varying intervals between successive exposures.

PubMed

Edwards, M J; Gray, C H; Beatson, J

1984-04-01

Guinea pigs were exposed to a temperature of 42.5-43.5 degrees C on three occasions between days 20 and 23 of pregnancy. In the first experiment, groups of mothers were exposed at intervals of 18-30 hr. Each exposure ended when the deep rectal temperature had been over 43 degrees C for 6 min and mean temperatures were 43.2-43.4 degrees C. Micrencephaly was found in 78% of heated newborn offspring, the mean brain weights of all groups being significantly less than controls. In the heated groups, the brain weights were reduced significantly as the interval between exposures decreased. Abnormalities other than micrencephaly were found in 10% of heated offspring and included exomphalos, clubfoot, and hypodactyly. In the second experiment, groups of mothers were exposed for 1 hour at intervals of 6-20 hr. The mean temperatures of heated groups were 42.6-42.9 degrees C. The mean brain weights of all groups of heated newborn were significantly reduced and micrencephaly was found in 61% of newborn. Brain weights were reduced significantly as mean maternal temperature increased. There was a significant interaction between the level of temperature elevation and the interval between exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative analysis of heat waves and associated mortality in St. Louis, Missouri--1980 and 1995.

PubMed

Smoyer, K E

1998-08-01

This research investigates heat-related mortality during the 1980 and 1995 heat waves in St. Louis, Missouri. St. Louis has a long history of extreme summer weather, and heat-related mortality is a public health concern. Heat waves are defined as days with apparent temperatures exceeding 40.6 degrees C (105 degrees F). The study uses a multivariate analysis to investigate the relationship between mortality and heat wave intensity, duration, and timing within the summer season. The heat wave of 1980 was more severe and had higher associated mortality than that of 1995. To learn if changing population characteristics, in addition to weather conditions, contributed to this difference, changes in population vulnerability between 1980 and 1995 are evaluated under simulated heat wave conditions. The findings show that St. Louis remains at risk of heat wave mortality. In addition, there is evidence that vulnerability has increased despite increased air-conditioning penetration and public health interventions.

Morphology and phase evolution in microwave synthesized Al/FeO4 system.

PubMed

Chuan, Lee Chang; Yoshikawaa, Noboru; Taniguchia, Shoji

2011-01-01

Thermite reaction between Al/Fe3O4 raised by microwave (MW) heating under N2 atmosphere has been investigated, and compared with that by the electric furnace. In addition to the stoichiometric ratio for the production of metallic iron and alumina, mixture with slightly Lower in Al content is also studied. As thermite reaction is highly exothermic, melting of reaction product and destruction of microstructure may occur, which corresponds to the enthalpy and adiabatic temperature of the reaction. Hence, to avoid this problem, reaction coupled with a smaller driving force by controlling the MW ignition condition at low temperature exotherm has been investigated. The phase and microstructure evolution during the reaction were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Thermogram of the DTA analysis, irrespective of their mole ratio, recorded two exothermic peaks, one at - 1310 degrees C and another one at - 1370 degrees C. When heated by microwave at 955 degrees C, the main products were identified as Al, FeO and Fe, minor amount of Fe3O4 and some Fe and alumina were detected. When heating to 1155 degrees C, Al and Fe3O4 peaks disappeared, formation of Fe-Al alloy was observed. For sample heated at 1265 degrees C, a porous body was obtained. Micron sized metal particles with complex morphology, irregular in size and shapes were formed, uniformly distributed within the spinel hercynite and/or alumina matrix. In contrast, conventional heating produced no porous products. Formation of alumina is also observed around the metal particles. Controlling of the reaction progress was possible while heating the sample by MW around the low temperature exotherm region, whereas the combustion wave could not be self-propagated.

Heat flow, deep formation temperature and thermal structure of the Tarim Basin, northwest China

NASA Astrophysics Data System (ADS)

Liu, Shaowen; Lei, Xiao; Feng, Changge; Li, Xianglan

2016-04-01

Geothermal regime of a sedimentary basin not only provides constraint on understanding the basin formation and evolution, but also offers fundamental parameters for hydrocarbon resources assessment. As one of three Precambrian blocks in China, the Tarim craton is also a current hydrocarbon exploration target where the largest sedimentary basin (Tarim Basin) develops with great potential. Although considerable advancement of geothermal regime of this basin has been made during the past decades, nearly all the temperature data in previous studies are from the exploration borehole formation testing temperatures. Recently, we have conducted the steady-state temperature logging in the Tarim basin, and measured abundant rock thermal properties, enabling us to re-visit the thermal regime of this area with more confidence. Our results show that the present-day geothermal gradients for the Tarim Basin vary from 23 K/km to 27 K/km, with a mean of 22 K/km; the values of heat flow range from 40 mW/m2 to 49 mW/m2, with a mean of 43 mW/m2. These new data confirmed that the Tarim Basin has relatively low heat flow and shares similar geothermal regime with other Precambrian cratons in the world. In addition, the new temperatures from the steady-state logs are larger than the bottom hole temperatures (BHT) as 22 degree Celsius, indicating the thermal non-equilibrium for the BHTs used in previous studies. Spatial distribution of the estimated formation temperatures-at-depth of 1~5km within the basin is similar and mainly controlled by crystalline basement pattern. Generally, the temperatures at the depth of 1km range from 29 to 41 degree Celsius, with a mean of 35 degree Celsius; while the temperatures at 3km vary from 63 to 100 degree Celsius, and the mean is 82 degree Celsius; at 5km below the surface, the temperatures fall into a range between 90 and 160 degree Celsius, with a mean of 129 degree Celsius. We further proposed the long-term low geothermal background and large burial depth are the favorable conditions for hydrocarbon generation and preservation. As far as heat budget of the Tarim Basin is concerned, the radiogenic heat from the sedimentary cover accounts only for 20 percent of the surface heat flow (~9 mW/m2), while the mantle heat flow is estimated to be low as 6~15 mW/m2; this indicates the dominant contribution of crustal radiogenic heat to the observed heat flow. Any variations in surface heat flow for the Tarim Basin can be due only to changes in crustal heat production. Thermal contrast between the Tarim Basin and Tibet Plateau, represented by a difference in surface heat flow and deep crustal temperature, is remarkable. This inherited thermal contrast can be traced as far as before the India-Asia collision. Moreover, the lithosphere beneath the Tarim Basin is sufficiently strong to resist the gravitational potential energy difference and tectonic forces from Tibet. The observed thermal and rheological contrast accounts for the differential Cenozoic deformation in the Tarim Basin and adjacent areas.

Substrate composition and moisture in composting source-separated human faeces and food waste.

PubMed

Niwagaba, C; Nalubega, M; Vinnerås, B; Sundberg, C; Jönsson, H

2009-04-14

The composting of a faeces/ash mixture and food waste in relative proportions of 1:0, 1:1 and 1:3 was studied in three successive experiments conducted in Kampala, Uganda in 216 L reactors insulated with 75 mm styrofoam or not insulated. The faeces/ash mixture alone exceeded 50 degrees C for < or = 12 days in insulated reactors, but did not reach or maintain 50 degrees C in non-insulated reactors. Inclusion of food waste kept temperatures above 50 degrees C for over two weeks in insulated reactors except when the substrate was too wet. Escherichia coli and total coliform concentrations decreased below detection in material that exceeded 50 degrees C for at least six days. Enterococcus spp. decreased below detection in material that exceeded 50 degrees C for at least two weeks, but remained detectable after 1.5 months in material that exceeded 50 degrees C for less than two weeks, suggesting that a period of at least two weeks above 50 degrees C, combined with mixing, is needed to achieve sanitation. Initially substrates that were too wet proved a challenge to composting and ways of decreasing substrate moisture should be investigated. The results obtained are applicable to the management of small- to medium-scale composting of faeces/ash and food waste at household and institution levels, e.g. schools and restaurants.

Developmental and hormonal regulation of thermosensitive neuron potential activity in rat brain.

PubMed

Belugin, S; Akino, K; Takamura, N; Mine, M; Romanovsky, D; Fedoseev, V; Kubarko, A; Kosaka, M; Yamashita, S

1999-08-01

To understand the involvement of thyroid hormone on the postnatal development of hypothalamic thermosensitive neurons, we focused on the analysis of thermosensitive neuronal activity in the preoptic and anterior hypothalamic (PO/AH) regions of developing rats with and without hypothyroidism. In euthyroid rats, the distribution of thermosensitive neurons in PO/AH showed that in 3-week-old rats (46 neurons tested), 19.5% were warm-sensitive and 80.5% were nonsensitive. In 5- to 12-week-old euthyroid rats (122 neurons), 33.6% were warm-sensitive and 66.4% were nonsensitive. In 5- to 12-week-old hypothyroid rats (108 neurons), however, 18.5% were warm-sensitive and 81.5% were nonsensitive. Temperature thresholds of warm-sensitive neurons were lower in 12-week-old euthyroid rats (36.4+/-0.2 degrees C, n = 15, p<0.01,) than in 3-week-old and in 5-week-old euthyroid rats (38.5+/-0.5 degrees C, n = 9 and 38.0+/-0.3 degrees C, n = 15, respectively). The temperature thresholds of warm-sensitive neurons in 12-week-old hypothyroid rats (39.5+/-0.3 degrees C, n = 8) were similar to that of warm-sensitive neurons of 3-week-old raats (euthyroid and hypothyroid). In contrast, there was no difference in the thresholds of warm-sensitive neurons between hypothyroid and euthyroid rats at the age of 3-5 weeks. In conclusion, monitoring the thermosensitive neuronal tissue activity demonstrated the evidence that thyroid hormone regulates the maturation of warm-sensitive hypothalamic neurons in developing rat brain by electrophysiological analysis.

Cryopreservation of Populus trichocarpa and Salix dormant buds with recovery by grafting or direct rooting.

PubMed

Bonnart, Remi; Waddell, John; Haiby, Kathy; Widrlenchner, Mark P; Volk, Gayle M

2014-01-01

Methods are needed for the conservation of clonally maintained trees of Populus and Salix. In this work, Populus trichocarpa and Salix genetic resources were cryopreserved using dormant scions as the source explant. We quantified the recovery of cryopreserved materials that originated from diverse field environments by using either direct sprouting or grafting. Scions (either at their original moisture content of 48 to 60% or dried to 30%) were slowly cooled to -35 degree C, transferred to the vapor phase of liquid nitrogen (LNV, -160 degree C), and warmed before determining survival. Dormant buds from P. trichocarpa clones from Westport and Boardman, OR had regrowth levels between 42 and 100%. Direct rooting of cryopreserved P. trichocarpa was also possible. Ten of 11 cryopreserved Salix accessions, representing 10 different species, exhibited at least 40% bud growth and rooting after 6 weeks when a bottom-heated rooting system was implemented. We demonstrate that dormant buds of P. trichocarpa and Salix accessions can be cryopreserved and successfully regenerated without the use of tissue culture.

The effect of food temperature on postprandial metabolism in albatrosses.

PubMed

Battam, H; Chappell, M A; Buttemer, W A

2008-04-01

Heat generated by the specific dynamic action (SDA) associated with feeding is known to substitute for the thermoregulatory costs of cold-exposed endotherms; however, the effectiveness of this depends on food temperature. When food is cooler than core body temperature, it is warmed by body heat and, consequently, imposes a thermoregulatory challenge to the animal. The degree to which this cost might be ;paid' by SDA depends on the relative timing of food heating and the SDA response. We investigated this phenomenon in two genera of endotherms, Diomedea and Thalassarche albatrosses, by measuring postprandial metabolic rate following ingestion of food at body temperature (40 degrees C) and cooler (0 and 20 degrees C). This permitted us to estimate potential contributions to food warming by SDA-derived heat, and to observe the effect of cold food on metabolic rate. For meal sizes that were approximately 20% of body mass, SDA was 4.22+/-0.37% of assimilated food energy, and potentially contributed 17.9+/-1.0% and 13.2+/-2.2% of the required heating energy of food at 0 degrees C for Diomedea and Thalassarche albatrosses, respectively, and proportionately greater quantities at higher food temperatures. Cold food increased the rate at which postprandial metabolic rate increased to 3.2-4.5 times that associated with food ingested at body temperature. We also found that albatrosses generated heat in excess by more than 50% of the estimated thermostatic heating demand of cold food, a probable consequence of time delays in physiological responses to afferent signals.

The effects of acclimatization on blood clotting parameters in exertional heat stress.

PubMed

Vesić, Zoran; Vukasinović-Vesić, Milica; Dincić, Dragan; Surbatović, Maja; Radaković, Sonja S

2013-07-01

Exertional heat stress is a common problem in military services. Considering the coagulation abnormalities are of major importance in development of severe heat stroke, we wanted to examine changes in hemostatic parameters in soldiers during exertional heat stress test as well as the effects of a 10-day passive or active acclimatization in a climatic chamber. A total of 40 male soldiers with high aerobic capacity performed exertional heat stress test (EHST) either in cool [20 degrees C, 16 degrees C wet bulb globe temperature (WBGT)], or hot (40 degrees C, 29 degrees C, (WBGT) environment, unacclimatized (U) or after 10 days of passive (P) or active (A) acclimatization. Physiological strain was measured by tympanic temperatures (Tty) and heart rates (HR). Platelet count (PC), antithrombin III (AT), and prothrombin time (PT) were assessed in blood samples collected before and immediately after the EHST. EHST in hot conditions induced physiological heat stress (increase in Tty and HR), with a significant increase in prothrombin time in the groups U and A. Platelet counts were significantly higher after the EHST compared to the basic levels in all the investigated groups, regardless environmental conditions and acclimatization state. Antithrombin levels were not affected by EHST whatsoever. In the trained soldiers, physiological heat stress caused mild changes in some serum parameters of blood clotting such as prothrombin time, while others such as antithrombin levels were not affected. Platelet counts were increased after EHST in all groups. A 10-day passive or active acclimatization in climatic chamber showed no effect on parameters investigated.

Liquid uranium alloy-helium fission reactor

DOEpatents

Minkov, Vladimir

1986-01-01

This invention teaches a nuclear fission reactor having a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200.degree.-1800.degree. C. range, and even higher to 2500.degree. C., limited only by the thermal effectiveness of the structural materials, increasing the efficiency of power generation from the normal 30-35% with 300.degree.-500.degree. C. upper limit temperature to 50-65%. Irradiation of the circulating liquid fuel, as contrasted to only localized irradiation of a solid fuel, provides improved fuel utilization.

The impact of climate change on air conditioning requirements in Andalusia at a detailed scale

NASA Astrophysics Data System (ADS)

Limones-Rodríguez, Natalia; Marzo-Artigas, Javier; Pita-López, María Fernanda; Díaz-Cuevas, María Pilar

2017-11-01

This work calculates the current heating and cooling degree days and also examines heating and cooling degree days in relation to three subdivisions of the twenty-first century. On the basis of these data, we were able to calculate the heating and cooling degree months and degree years. After examining both sets of data, we studied the total needs of air conditioning—also referred to in the current paper as climatization needs——for Andalusia as a whole. The results indicate an increase in air conditioning needs, and we also noted that the areas adversely affected by this increase were more numerous than those which benefited, at the end of the century. It should be noted that climate change will also necessitate the gradual replacement of heating with cooling, which will require profound changes in the energy, land planning, and housing policies of the region. The true magnitude of the challenge becomes clear when the climatization degree days are related to the population which they affect; the majority of the population is located in areas where the climatization needs will increase over the course of the century. Undoubtedly, this issue is a major protagonist in the climate change adaptation process in Andalusia.

The effects of passive heating and head-cooling on perception of exercise in the heat.

PubMed

Simmons, Shona E; Mündel, Toby; Jones, David A

2008-09-01

The capacity to perform exercise is reduced in a hot environment when compared to cooler conditions. A limiting factor appears to be a higher core body temperature (T (core)) and it has been suggested that an elevated T (core) reduces the drive to exercise, this being reflected in higher ratings of perceived exertion (RPE). The purpose of the present study was to determine whether passive heating to increase T (core) would have a detrimental effect on RPE and thermal comfort during subsequent exercise in the heat and whether head-cooling during passive heating would attenuate these unpleasant sensations of an elevated T (core) during subsequent exercise in the heat. Nine physically-active, non-heat-acclimated volunteers [6 males, 3 females; age: 21 +/- 1 year, VO(2max) 50 +/- 9 ml kg(-1).min(-1), peak power output: 286 +/- 43 W (mean +/- SD)] performed two 12-minute constant-load cycling tests at 70% VO(2max) in a warm-dry environment (34 +/- 1 degrees C, relative humidity <30%) separated by a period of passive heating in a sauna (68 +/- 3 degrees C) to increase T (core). In one trial, subjects had their head and face cooled continually in the sauna (HC), the other trial was a control (CON). Passive heating increased T (core) by 1.22 +/- 0.03 degrees C in the CON and by 0.75 +/- 0.07 degrees C in the HC trial (P < 0.01). Passive heating increased weighted mean skin temperature (T (msk)) in both the CON and HC trials (P < 0.01), however, head-cooling lowered T (msk) during passive heating (P < 0.05). Exercise time following passive heating was reduced in both the CON and HC trials (P < 0.05). Passive heating increased RPE (P < 0.01), however, RPE was lower following passive heating with head-cooling (P < 0.05). There was a significant correlation between T (core) and RPE (r = 0.82, P < 0.001). In conclusion, our results suggest increased RPE during exercise in the heat is primarily due to the increase in T (core). Furthermore, head-cooling attenuates the rise in T (core) and the effect on RPE is proportional to the rise on T (core).

Shivering heat production and core cooling during head-in and head-out immersion in 17 degrees C water.

PubMed

Pretorius, Thea; Cahill, Farrell; Kocay, Sheila; Giesbrecht, Gordon G

2008-05-01

Many cold-water scenarios cause the head to be partially or fully immersed (e.g., ship wreck survival, scuba diving, cold-water adventure swim racing, cold-water drowning, etc.). However, the specific effects of head cold exposure are minimally understood. This study isolated the effect of whole-head submersion in cold water on surface heat loss and body core cooling when the protective shivering mechanism was intact. Eight healthy men were studied in 17 degrees C water under four conditions: the body was either insulated or exposed, with the head either out of the water or completely submersed under the water within each insulated/exposed subcondition. Submersion of the head (7% of the body surface area) in the body-exposed condition increased total heat loss by 11% (P < 0.05). After 45 min, head-submersion increased core cooling by 343% in the body-insulated subcondition (head-out: 0.13 +/- 0.2 degree C, head-in: 0.47 +/- 0.3 degree C; P < 0.05) and by 56% in the body-exposed subcondition (head-out: 0.40 +/- 0.3 degree C and head-in: 0.73 +/- 0.6 degree C; P < 0.05). In both body-exposed and body-insulated subconditions, head submersion increased the rate of core cooling disproportionally more than the relative increase in total heat loss. This exaggerated core-cooling effect is consistent with a head cooling induced reduction of the thermal core, which could be stimulated by cooling of thermosensitive and/or trigeminal receptors in the scalp, neck, and face. These cooling effects of head submersion are not prevented by shivering heat production.

Microdistribution of Impurities in Semiconductors and its Influence on Photovoltaic Energy Conversion.

NASA Astrophysics Data System (ADS)

Rava, Paolo

In the present investigation the interstitial oxygen distribution in silicon has been measured on a microscale and correlated to the activation of thermal donors by 450(DEGREES)C heat treatment. Scanning IR absorption was used to measure the axyal oxygen microdistribution at different distances from the edge of the crystal. The free carrier microdistribution along the same locations was measured, after a 450(DEGREES)C heat treatment, using a spreading resistance probe. A comparison of the two microprofiles revealed direct correspondence in the general features, but no correlation between oxygen and thermal donor concentration in some areas; in particular, no activation of donors took place in some areas. After a 650(DEGREES)C heat treatment, all donors were annihilated; after subsequent 450(DEGREES)C heat treament, donors were activated again, but in a different pattern: the areas which were activated the first time now exhibited smaller densities of thermal donors and the areas which were not previously activated exhibited high donor concentration. The microdefect distribution was studied as a function of heat treatment time and compared to the activated donor microprofiles. A high density of B-defects was found in areas where no donor activation took place upon the first heat treatment at 450(DEGREES)C, whereas A-defects were present in areas where donors were activated. Upon 650(DEGREES)C heat treatment B-defects became large and less dense, approaching A-defects and allowing activation of donors upon further 450(DEGREES)C heat treatment. These results are qualitatively in agreement with the vacancy-oxygen model proposed for donor activation. According to this model, an oxygen atom can slip into a silicon vacancy and be bound to this site by bonding one of its electrons with another nearest neighbor vacancy; this complex can then be easily ionized by releasing the extra electron. A neighbor vacancy diffused at 650(DEGREES)C can trap this free electron to form an electrically inert complex. The presence of unactivated areas close to the crystal periphery was attributed to a lower concentration of available vacancies due to the presence of the B-defects (vacancy clusters); a 650(DEGREES)C heat treatment changed their structure, possibly releasing vacancies which then participated in donor formation. On the other hand, the areas activated the first time at 450(DEGREES)C have fewer vacancies available the second time for donor formation and therefore are less activated. It was shown that the vacancy-oxygen complex must be the first step in the formation of multivacancy or any multioxygen donor complexes. The role of a factor other than oxygen in donor activation can be revealed only by a microscale analysis such as the one presented here. In fact, the areas in which donor formation is enhanced by 650(DEGREES)C heat treatment are completely undetected in a macroscale analysis, which therefore would lead to a proportionality between oxygen concentration and activated donors. This work shows that the accepted premise that the concentration of oxygen donors is proportional to the oxygen concentration is not generally valid. Multiple p-n junctions have been prepared in b -doped Si through overcompensation near the oxygen periodic concentration maxima by thermal donors generated during an appropriate heat treatment at 450(DEGREES)C. Application of this structure to photovoltaic energy conversion has been investigated. A new solar cell structure based on multiple p-n junctions was developed and tested. An increase in short circuit current was achieved, but at the same time a degradation in open circuit voltage occurred. An interpretation of the experimental data in the light of the results of a computer simulation showed that an overall increase in efficiency can be achieved in this structure with a small and regular junction spacing. The effect of carrier density inhomogeneities in InP and GaAs samples was then investigated. The same scanning IR absorption technique employed in the first part of this study was used to measure free carrier microprofiles in order to determine the homogeneity of the samples. It was established that the presence of inhomogeneities can lead to a significant ambiguity in the determination on a macroscale of mobility, carrier concentration and absorption coefficient.

[Influence of anisodamine on heat-stress in rats].

PubMed

Tang, Wenchun; Wang, Baofang; Xu, Xiaobo; Liu, Guangchao; Duan, Yongjian

2002-02-01

To study whether previously intravenous injection of anisodamine can prevent endotoxemia of heat stroke of rats. Experimental animals were randomly divided into two groups, their average artery pressure, heart rate, survival time, survival rate and rectal temperature were measured at an environmental temperature of 38 degrees C-40 degrees C and 50%-60% retative humidity. Blood samples for endotoxins analyses were taken both before and after heat-stress. During heat stress, the animals of rectal temperature of the experimental and control groups continuously increased and two hours later, separately to (42.7 +/- 0.6) degree C and (43.1 +/- 0.5) degree C, without statistic difference(P > 0.05), and to (44.6 +/- 0.4) degree C and (44.2 +/- 0.3) degree C prior to death, with statistic difference(P < 0.05). Before the experiment, the contents of endotoxins of portal vein blood were (45.7 +/- 5.2) pg/ml and (42.6 +/- 5.4) pg/ml, and that of systemic blood was (14.8 +/- 4.5) pg/ml and (13.9 +/- 7.2) pg/ml, without statistic difference(P > 0.05). Two hours later, the contents of portal vein blood separately increased to (122.2 +/- 16.7) pg/ml and (49.7 +/- 10.2) pg/ml, obviously higher than that before heat-stress(P < 0.01). And there were clear statistic difference between the two groups(P < 0.01). The changing tendency of the heart rhythm is almost the same in two groups, that is, first rose and then fell. But it is without statistic difference before and two hours later(P > 0.05): before heat-stress, the average artery pressures were (13.3 +/- 0.6) kPa and (13.6 +/- 0.5) kPa, without statistic difference(P > 0.05), and two hours later, were (9.6 +/- 0.5) kPa and (8.6 +/- 0.6) kPa, with obvious statistic difference(P < 0.01). The survival time of the animals were (166.5 +/- 16.9) min and (144.5 +/- 18.2) min with obvious statistic difference(P < 0.01), the survival rate of heat stressed rats in the experimental group were obviously higher than control group(P < 0.01 or P < 0.05). Anisodamine can prevent endotoxemia in rats suffering heat stroke.

Antimicrobial effect and shelf-life extension by combined thermal and pulsed electric field treatment of milk.

PubMed

Walkling-Ribeiro, M; Noci, F; Cronin, D A; Lyng, J G; Morgan, D J

2009-01-01

The impact of a combined hurdle treatment of heat and pulsed electric fields (PEF) was studied on native microbiota used for the inoculation of low-fat ultra-high temperature (UHT) milk and whole raw milk. Microbiological shelf-life of the latter following hurdle treatment or thermal pasteurization was also investigated. UHT milk was preheated to 30 degrees C, 40 degrees C or 50 degrees C over a 60-s period, pulsed for 50 micros or 60 micros at a field strength of 40 kV cm(-1) or for 33 micros at 50 kV cm(-1). Heat and PEF reduced the microbial count by a maximum of 6.4 log in UHT milk (50 degrees C; 50 kV cm(-1), 33 micros) compared to 6.0 log (P > or = 0.05) obtained by thermal pasteurization (26 s, 72 degrees C). When raw milk was treated with a combination of hurdles (50 degrees C; 40 kV cm(-1), 60 micros) a 6.0 log inactivation of microbiota was achieved and microbiological milk shelf-life was extended to 21 days under refrigeration (4 degrees C) vs 14 days in thermally pasteurized milk. Native microbiota was decreased by 6.7 log following conventional pasteurization. The findings suggest that heat and PEF achieved similar inactivation of native microbiota in milk and longer stabilization of microbiological shelf-life than thermal pasteurization. A hurdle approach of heat and PEF could represent a valid milk processing alternative to conventional pasteurization. Hurdle treatment might also preserve native milk quality better due to less thermal exposure.

Time course and magnitude of synthesis of heat-shock proteins in congeneric marine snails (Genus tegula) from different tidal heights.

PubMed

Tomanek, L; Somero, G N

2000-01-01

The time course and magnitude of the heat-shock response in relation to severity of thermal stress are important, yet poorly understood, aspects of thermotolerance. We examined patterns of protein synthesis in congeneric marine snails (genus Tegula) that occur at different heights along the subtidal to intertidal gradient after a thermal exposure (30 degrees C for 2.5 h, followed by 50 h recovery at 13 degrees C) that induced the heat-shock response. We monitored the kinetics and magnitudes of protein synthesis by quantifying incorporation of 35S-labeled methionine and cysteine into newly synthesized proteins and observed synthesis of putative heat-shock proteins (hsp's) of size classes 90, 77, 70, and 38 kDa. In the low- to mid-intertidal species, Tegula funebralis, whose body temperature frequently exceeds 30 degrees C during emersion, synthesis of hsp's commenced immediately after heat stress, reached maximal levels 1-3 h into recovery, and returned to prestress levels by 6 h, except for hsp90 (14 h). In contrast, in the low-intertidal to subtidal species, Tegula brunnea, for which 2.5 h at 30 degrees C represents a near lethal heat stress, synthesis of hsp's commenced 2-14 h after heat stress; reached maximal levels after 15-30 h, which exceeded magnitudes of synthesis in T. funebralis; and returned to prestress levels in the case of hsp90 (50 h) and hsp77 (30 h) but not in the case of hsp70 and hsp38. Exposures to 30 degrees C under aerial (emersion) and aquatic (immersion) conditions resulted in differences in hsp synthesis in T. brunnea but not in T. funebralis. The different time courses and magnitudes of hsp synthesis in these congeners suggest that the vertical limits of their distributions may be set in part by thermal stress.

Sporulation and germination gene expression analysis of Bacillus anthracis Sterne spores in skim milk under heat and different intervention techniques

USDA-ARS?s Scientific Manuscript database

To investigate how B. anthracis Stene spores survive in milk under heat (80 degree C, 10 minutes), pasteurization (72 degree C, 15 seconds) and pasteurization plus microfiltration, the expression levels of genes that related to sporulation and germination were tested using real-time PCR assays. Tw...

Method of fabrication of anchored nanostructure materials

DOEpatents

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2013-11-26

Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

Comparison of effects of high-pressure processing and heat treatment on immunoactivity of bovine milk immunoglobulin G in enriched soymilk under equivalent microbial inactivation levels.

PubMed

Li, Si-Quan; Zhang, Howard Q; Balasubramaniam, V M; Lee, Young-Zoon; Bomser, Joshua A; Schwartz, Steven J; Dunne, C Patrick

2006-02-08

Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf life of functional foods enriched with bovine immunoglobulin G (IgG), nonthermal alternatives such as high-pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on the immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, was subjected to HPP or heat treatment. To achieve a 5 log reduction in inoculated Escherichia coli 8739, the HPP or heat treatment requirements were 345 MPa for 4 min at 30 degrees C or for 20 s at 70 degrees C, respectively. To achieve a 5 log reduction in natural flora in the enriched soymilk, the HPP or heat treatments needed were 552 MPa for 4 min at 30 degrees C or for 120 s at 78.2 degrees C, respectively. At equivalent levels for a 5 log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5 log reduction in natural flora, HPP and heat resulted in 65 and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine the optimal process conditions to preserve product function.

The contact heat transfer between the heating plate and granular materials in rotary heat exchanger under overloaded condition

NASA Astrophysics Data System (ADS)

Duan, Luanfang; Qi, Chonggang; Ling, Xiang; Peng, Hao

2018-03-01

In the present work, the contact heat transfer between the granular materials and heating plates inside plate rotary heat exchanger (PRHE) was investigated. The heat transfer coefficient is dominated by the contact heat transfer coefficient at hot wall surface of the heating plates and the heat penetration inside the solid bed. A plot scale PRHE with a diameter of Do = 273 mm and a length of L = 1000 mm has been established. Quartz sand with dp = 2 mm was employed as the experimental material. The operational parameters were in the range of ω = 1 - 8 rpm, and F = 15, 20, 25, 30%, and the effect of these parameters on the time-average contact heat transfer coefficient was analyzed. The time-average contact heat transfer coefficient increases with the increase of rotary speed, but decreases with the increase of the filling degree. The measured data of time-average heat transfer coefficients were compared with theoretical calculations from Schlünder's model, a good agreement between the measurements and the model could be achieved, especially at a lower rotary speed and filling degree level. The maximum deviation between the calculated data and the experimental data is approximate 10%.

Using Annual Data to Estimate the Public Health Impact of Extreme Temperatures.

PubMed

Goggins, William B; Yang, Chunyuh; Hokama, Tomiko; Law, Lewis S K; Chan, Emily Y Y

2015-07-01

Short-term associations between both hot and cold ambient temperatures and higher mortality have been found worldwide. Few studies have examined these associations on longer time scales. Age-standardized mortality rates (ASMRs) were calculated for 1976-2012 for Hong Kong SAR, People's Republic of China, defining "annual" time periods in 2 ways: from May through April of the following year and from November through October. Annual frequency and severity of extreme temperatures were summarized by using a degree-days approach with extreme heat expressed as annual degree-days >29.3°C and cold as annual degree-days <27.5°C. For example, a day with a mean temperature of 25.0°C contributes 2.5 cold degree-days to the annual total. Generalized additive models were used to estimate the association between annual hot and cold degree-days and the ASMR, with adjustment for long-term trends. Increases of 10 hot or 200 cold degree-days in an annual period, the approximate interquartile ranges for these variables, were significantly (all P's ≤ 0.011) associated with 1.9% or 3.1% increases, respectively, in the annual ASMR for the May-April analyses and with 2.2% or 2.8% increases, respectively, in the November-October analyses. Associations were stronger for noncancer and elderly mortality. Mortality increases associated with extreme temperature are not simply due to short-term forward displacement of deaths that would have occurred anyway within a few weeks. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Temporal heating profile influence on the immediate bond strength following laser tissue soldering.

PubMed

Rabi, Yaron; Katzir, Abraham

2010-07-01

Bonding of tissues by laser heating is considered as a future alternative to sutures and staples. Increasing the post-operative bond strength remains a challenging issue for laser tissue bonding, especially in organs that have to sustain considerable tension or pressure. In this study, we investigated the influence of different temporal heating profiles on the strength of soldered incisions. The thermal damage following each heating procedure was quantified, in order to assess the effect of each heating profile on the thermal damage. Incisions in porcine bowel tissue strips (1 cmx4 cm) were soldered, using a 44% liquid albumin mixed with indocyanine green and a temperature controlled laser (830 nm) tissue bonding system. Heating was done either with a linear or a step temporal heating profile. The incisions were bonded by soldering at three points, separated by 2 mm. Set-point temperatures of T(set) = 60, 70, 80, 90, 100, 110, 150 degrees C and dwell times of t(d) = 10, 20, 30, 40 seconds were investigated. The bond strength was measured immediately following each soldering by applying a gradually increased tension on the tissue edges until the bond break. Bonds formed by linear heating were stronger than the ones formed by step heating: at T(set) = 80 degrees C the bonds were 40% stronger and at T(set) = 90 degrees C the bonds strength was nearly doubled. The bond strength difference between the heating methods was larger as T(set) increased. Linear heating produced stronger bonds than step heating. The difference in the bond strength was more pronounced at high set-point temperatures and short dwell times. The bond strength could be increased with either higher set-point temperature or a longer dwell time.

Develop to Term Rat Oocytes Injected with Heat-Dried Sperm Heads

PubMed Central

Lee, Kyung-Bon; Park, Ki-Eun; Kwon, In-Kiu; Tripurani, Swamy K.; Kim, Keun Jung; Lee, Ji Hye; Niwa, Koji; Kim, Min Kyu

2013-01-01

This study investigated the development of rat oocytes in vitro and in vivo following intracytoplasmic injection of heads from spermatozoa heat-dried at 50°C for 8 h and stored at 4°C in different gas phases. Sperm membrane and chromosome are damaged by the process of heat-drying. Oocyte activation and cleavage of oocytes were worse in oocytes injected with spermatozoa heat-dried and stored for 1 week than unheated, fresh spermatozoa, but in heat-dried spermatozoa, there were no differences in these abilities of oocytes between the samples stored in nitrogen gas and in air. The oocytes injected with heat-dried spermatozoa stored for 1 week could develop to the morula and blastocyst stages without difference between the samples stored in nitrogen gas and in air after artificial stimulation. Cleavage of oocytes and development of cleaved embryos were higher when heat-dried spermatozoa were stored for 3 and 6 months in nitrogen gas than in air. However, the ability of injected oocytes to develop to the morula and blastocyst stages was not inhibited even when heat-dried spermatozoa stored in both atmosphere conditions for as long as 6 months were used. When 2-cell embryos derived from oocytes injected with heads from spermatozoa heat-dried and stored for 1 week and 1 month were transferred, each 1 of 4 recipients was conceived, and the conceived recipients delivered 1 live young each. These results demonstrate that rat oocytes can be fertilized with heat-dried spermatozoa and that the fertilized oocytes can develop to term. PMID:24223784

In vitro radicular temperatures produced by injectable thermoplasticized gutta-percha.

PubMed

Weller, R N; Koch, K A

1995-03-01

In vitro temperatures produced in the root canal and on the root surface were measured simultaneously as heated gutta-percha was injected into the prepared canal. The canals were obturated with the Obtura II heated gutta-percha system with temperature settings of 160, 185, and 200 degrees C. The mean intracanal temperatures ranged from 40.21 to 57.24 degrees C, whereas the mean root surface temperatures were recorded from 37.22 to 41.90 degrees C for all three temperatures tested. The rise in temperature on the root surface was below the critical level of 10 degrees C and should not cause damage to the periodontal ligament.

Vitrification of waste

DOEpatents

Wicks, George G.

1999-01-01

A method for encapsulating and immobilizing waste for disposal. Waste, preferably, biologically, chemically and radioactively hazardous, and especially electronic wastes, such as circuit boards, are placed in a crucible and heated by microwaves to a temperature in the range of approximately 300.degree. C. to 800.degree. C. to incinerate organic materials, then heated further to a temperature in the range of approximately 1100.degree. C. to 1400.degree. C. at which temperature glass formers present in the waste will cause it to vitrify. Glass formers, such as borosilicate glass, quartz or fiberglass can be added at the start of the process to increase the silicate concentration sufficiently for vitrification.

High-temperature zirconia insulation and method for making same

DOEpatents

Wrenn, Jr., George E.; Holcombe, Jr., Cressie E.; Lewis, Jr., John

1988-01-01

The present invention is directed to a highly pure, partially stabilized, fibrous zirconia composite for use as thermal insulation in environments where temperatures up to about 2000.degree. C. are utilized. The composite of the present invention is fabricated into any suitable configuration such as a cone, cylinder, dome or the like by vacuum molding an aqueous slurry of partially stabilized zirconia fibers into a desired configuration on a suitably shaped mandrel. The molded fibers are infiltrated with zirconyl nitrate and the resulting structure is then dried to form a rigid structure which may be removed and placed in a furnace. The structure is then heated in air to a temperature of about 600.degree. C. for driving off the nitrate from the structure and for oxidizing the zirconyl ion to zirconia. Thereafter, the structure is heated to about 950.degree. to 1,250.degree. C. to fuse the zirconia fibers at their nexi in a matrix of zirconia. The composite produced by the present invention is self-supporting and can be readily machined to desired final dimensions. Additional heating to about 1800.degree. to 2000.degree. C. further improves structural rigidity.

Effect on orange juice of batch pasteurization in an improved pilot-scale microwave oven.

PubMed

Cinquanta, L; Albanese, D; Cuccurullo, G; Di Matteo, M

2010-01-01

The effects on orange juice batch pasteurization in an improved pilot-scale microwave (MW) oven was evaluated by monitoring pectin methyl-esterase (PME) activity, color, carotenoid compounds and vitamin C content. Trials were performed on stirred orange juice heated at different temperatures (60, 70, 75, and 85 degrees C) during batch process. MW pilot plant allowed real-time temperature control of samples using proportional integrative derivative (PID) techniques based on the infrared thermography temperature read-out. The inactivation of heat sensitive fraction of PME, that verifies orange juice pasteurization, showed a z-value of 22.1 degrees C. Carotenoid content, responsible for sensorial and nutritional quality in fresh juices, decreased by about 13% after MW pasteurization at 70 degrees C for 1 min. Total of 7 carotenoid compounds were quantified during MW heating: zeaxanthin and beta-carotene content decreased by about 26%, while no differences (P < 0.05) were found for beta-cryptoxanthin in the same trial. A slight decrease in vitamin C content was monitored after MW heating. Results showed that MW heating with a fine temperature control could result in promising stabilization treatments.

An electronic cryoprobe for cryosurgery using heat pipes and thermoelectric coolers: a preliminary report.

PubMed

Hamilton, A; Hu, J

1993-01-01

A hand-held fully electrically powered and programmable cryoprobe for general-purpose cryosurgery and cryotherapy has been developed. By combining the technologies of thermoelectric cooling and heat pipes, the temperature at the tip of the probe can easily reach -50 to -60 degrees C. It can hold below -40 degrees C when it cools a load of 10 W at the tip. Previous efforts developing cryoprobes made of thermoelectric modules have been hindered by the inherent characteristics of commercially available thermoelectric coolers: low efficiency, size and inflexible shape and very sensitive to heat intensity and thermal insulation. Matching thermoelectrics with heat pipes uses the advantages of both technologies. In the cryoprobe the heat pipe is used to focus and transport the cooling power of multi-thermoelectric modules. The heat flux for the thermoelectric modules is reduced and their efficiencies are increased. The transport of heat by a heat pipe also allows flexible access to treated spots of patients.

Heat removal using microclimate foot cooling: a thermal foot manikin study.

PubMed

Castellani, John W; Demes, Robert; Endrusick, Thomas L; Cheuvront, Samuel N; Montain, Scott J

2014-04-01

It has been proposed that microclimate cooling systems exploit the peripheral extremities because of more efficient heat transfer. The purpose of this study was to quantify, using a patented microclimate cooling technique, the heat transfer from the plantar surface of the foot for comparison to other commonly cooled body regions. A military boot was fitted with an insole embedded with a coiled, 1.27 m length of hollow tubing terminating in inlet and outlet valves. A thermal foot manikin with a surface temperature of 34 degrees C was placed in the boot and the valves were connected to a system that circulated water through the insole at a temperature of 20 degrees C and flow rate of 120 ml x min(-1). The manikin foot served as a constant heat source to determine heat transfer provided by the insole. Testing was done with the foot model dry and sweating at a rate of 500 ml x h(- 1) x m(-2). Climatic chamber conditions were 30 degrees C with 30% RH. Heat loss was approximately 4.1 +/- 0.1 and approximately 7.7 +/- 0.3 W from the dry and sweating foot models, respectively. On a relative scale, the heat loss was 3.0 W and 5.5 W per 1% (unit) body surface area, respectively, for the dry and sweating conditions. The relative heat loss afforded by plantar foot cooling was similar compared to other body regions, but the absolute amount of heat removal is unlikely to make an impact on whole body heat balance.

Hydrogen permeation behavior through F82H at high temperature

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

Matsuda, S.; Katayama, K.; Shimozori, M.

2015-03-15

F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 tomore » 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)« less

Identification and characterization of an expansin gene AsEXP1 associated with heat tolerance in C3 Agrostis grass species.

PubMed

Xu, Jichen; Tian, Jiang; Belanger, Faith C; Huang, Bingru

2007-01-01

Plant tolerance of heat stress involves various changes at physiological and molecular levels. The objective of this study was to examine the expression of a gene encoding expansin protein in relation to heat tolerance in two C(3) grass species and genotypes differing in heat tolerance. Heat-tolerant, thermal Agrostis scabra, adapted to high temperatures in geothermal areas in Yellowstone National Park, was subjected to 20 degrees C (control) or 40 degrees C (heat stress) for 7 d in a growth chamber. Differential display analysis identified that a gene, AsEXP1, encoding an expansin protein, was strongly up-regulated in leaves exposed to heat stress in thermal A. scabra. Virtual northern hybridization and RT-PCR confirmed that AsEXP1 was a heat-inducible gene in leaves. The expression of AsEXP1 was induced at 1 h of plant exposure to heat stress and reached the highest level of expression at 4 h of treatment. A 1.3 kb full-length cDNA of AsEXP1 was isolated, which encodes a 251 amino acid protein. Two ecotypes of thermal A. scabra and 10 genotypes of Agrostis stolonifera (creeping bentgrass), a widely used turfgrass species in cool climatic regions, varying in the level of heat tolerance, were exposed to 40 degrees C for 7 d to examine the level of AsEXP1 expression in relation to heat tolerance. Genetic variation in heat tolerance was evaluated by measuring cell membrane stability, photochemical efficiency, and leaf growth. RT-PCR analysis revealed that the level of AsEXP1 in different genotypes was positively correlated with the level of heat tolerance in both grass species. The results first identified a heat-related expansin gene in grass species and suggest that AsEXP1 may be useful as a molecular marker to select for heat-tolerant grass germplasm.

Fluidized-Bed Heat Transfer Modeling for the Development of Particle/Supercritical-CO2 Heat Exchanger

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

Ma, Zhiwen; Martinek, Janna G

Concentrating solar power (CSP) technology is moving toward high-temperature and high-performance design. One technology approach is to explore high-temperature heat-transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (s-CO2) Brayton power cycle. The s-CO2 Brayton power system has great potential to enable the future CSP system to achieve high solar-to-electricity conversion efficiency and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat-transfer medium that is inexpensive and stable at high temperatures above 1,000 degrees C. The particle/heat exchanger provides a connection between the particles andmore » s-CO2 fluid in the emerging s-CO2 power cycles in order to meet CSP power-cycle performance targets of 50% thermal-to-electric efficiency, and dry cooling at an ambient temperature of 40 degrees C. The development goals for a particle/s-CO2 heat exchanger are to heat s-CO2 to =720 degrees C and to use direct thermal storage with low-cost, stable solid particles. This paper presents heat-transfer modeling to inform the particle/s-CO2 heat-exchanger design and assess design tradeoffs. The heat-transfer process was modeled based on a particle/s-CO2 counterflow configuration. Empirical heat-transfer correlations for the fluidized bed and s-CO2 were used in calculating the heat-transfer area and optimizing the tube layout. A 2-D computational fluid-dynamics simulation was applied for particle distribution and fluidization characterization. The operating conditions were studied from the heat-transfer analysis, and cost was estimated from the sizing of the heat exchanger. The paper shows the path in achieving the cost and performance objectives for a heat-exchanger design.« less

Sterilization System

NASA Technical Reports Server (NTRS)

1990-01-01

Cox Sterile Products, Inc.'s Rapid Heat Transfer Sterilizer employs a heat exchange process that induces rapid air movement; the air becomes the heat transfer medium, maintaining a uniform temperature of 375 degrees Fahrenheit. It features pushbutton controls for three timing cycles for different instrument loads, a six-minute cycle for standard unpackaged instruments, eight minutes for certain specialized dental/medical instruments and 12 minutes for packaged instruments which can then be stored in a drawer in sterile condition. System will stay at 375 degrees all day. Continuous operation is not expensive because of the sterilizer's very low power requirements.

Method for encapsulating nanoparticles in a zeolite matrix

DOEpatents

Coker, Eric N.

2007-12-11

A method for preparing a metal nanocluster composite material. A porous zeolitic material is treated with an aqueous metal compound solution to form a metal ion-exchanged zeolitic material, heated at a temperature ramp rate of less than 2.degree. C./min to an elevated temperature, cooled, contacted with an organic monomer and heating to induce polymerization, and heating the composite material to greater than 350.degree. C. under non-oxidizing conditions to form a metal nanocluster-carbon composite material with nanocluster sizes between approximately 0.6 nm and 10 nm.

[Scanning electron microscopy of heat-damaged bone tissue].

PubMed

Harsanyl, L

1977-02-01

Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

Radiation-induced heat-labile sites that convert into DNA double-strand breaks

NASA Technical Reports Server (NTRS)

Rydberg, B.; Chatterjee, A. (Principal Investigator)

2000-01-01

The yield of DNA double-strand breaks (DSBs) in SV40 DNA irradiated in aqueous solution was found to increase by more than a factor of two as a result of postirradiation incubation of the DNA at 50 degrees C and pH 8.0 for 24 h. This is in agreement with data from studies performed at 37 degrees C that were published previously. Importantly, similar results were also obtained from irradiation of mammalian DNA in agarose plugs. These results suggest that heat-labile sites within locally multiply damaged sites are produced by radiation and are subsequently transformed into DSBs. Since incubation at 50 degrees C is typically employed for lysis of cells in commonly used pulsed-field gel assays for detection of DSBs in mammalian cells, the possibility that heat-labile sites are present in irradiated cells was also studied. An increase in the apparent number of DSBs as a function of lysis time at 50 degrees C was found with kinetics that was similar to that for irradiated DNA, although the magnitude of the increase was smaller. This suggests that heat-labile sites are also formed in the cell. If this is the case, a proportion of DSBs measured by the pulsed-field gel assays may occur during the lysis step and may not be present in the cell as breaks but as heat-labile sites. It is suggested that such sites consist mainly of heat-labile sugar lesions within locally multiply damaged sites. Comparing rejoining of DSBs measured with short and long lysis procedure indicates that the heat-labile sites are repaired with fast kinetics in comparison with repair of the bulk of DSBs.

Development and application of a specially designed heating system for temperature-programmed high-performance liquid chromatography using subcritical water as the mobile phase.

PubMed

Teutenberg, T; Goetze, H-J; Tuerk, J; Ploeger, J; Kiffmeyer, T K; Schmidt, K G; Kohorst, W gr; Rohe, T; Jansen, H-D; Weber, H

2006-05-05

A specially designed heating system for temperature-programmed HPLC was developed based on experimental measurements of eluent temperature inside a stainless steel capillary using a very thin thermocouple. The heating system can be operated at temperatures up to 225 degrees C and consists of a preheating, a column heating and a cooling unit. Fast cycle times after a temperature gradient can be realized by an internal silicone oil bath which cools down the preheating and column heating unit. Long-term thermal stability of a polybutadiene-coated zirconium dioxide column has been evaluated using a tubular oven in which the column was placed. The packing material was stable after 50h of operation at 185 degrees C. A mixture containing four steroids was separated at ambient conditions using a mobile phase of 25% acetonitrile:75% deionized water and a mobile phase of pure deionized water at 185 degrees C using the specially designed heating system and the PBD column. Analysis time could be drastically reduced from 17 min at ambient conditions and a flow rate of 1 mL/min to only 1.2 min at 185 degrees C and a flow rate of 5 mL/min. At these extreme conditions, no thermal mismatch was observed and peaks were not distorted, thus underlining the performance of the developed heating system. Temperature programming was performed by separating cytostatic and antibiotic drugs with a temperature gradient using only water as the mobile phase. In contrast to an isocratic elution of this mixture at room temperature, overall analysis time could be reduced two-fold from 20 to 10 min.

Changes In The Heating Degree-days In Norway Due Toglobal Warming

NASA Astrophysics Data System (ADS)

Skaugen, T. E.; Tveito, O. E.; Hanssen-Bauer, I.

A continuous spatial representation of temperature improves the possibility topro- duce maps of temperature-dependent variables. A temperature scenario for the period 2021-2050 is obtained for Norway from the Max-Planck-Institute? AOGCM, GSDIO ECHAM4/OPEC 3. This is done by an ?empirical downscaling method? which in- volves the use of empirical links between large-scale fields and local variables to de- duce estimates of the local variables. The analysis is obtained at forty-six sites in Norway. Spatial representation of the anomalies of temperature in the scenario period compared to the normal period (1961-1990) is obtained with the use of spatial interpo- lation in a GIS. The temperature scenario indicates that we will have a warmer climate in Norway in the future, especially during the winter season. The heating degree-days (HDD) is defined as the accumulated Celsius degrees be- tween the daily mean temperature and a threshold temperature. For Scandinavian countries, this threshold temperature is 17 Celsius degrees. The HDD is found to be a good estimate of accumulated cold. It is therefore a useful index for heating energy consumption within the heating season, and thus to power production planning. As a consequence of the increasing temperatures, the length of the heating season and the HDD within this season will decrease in Norway in the future. The calculations of the heating season and the HDD is estimated at grid level with the use of a GIS. The spatial representation of the heating season and the HDD can then easily be plotted. Local information of the variables being analysed can be withdrawn from the spatial grid in a GIS. The variable is prepared for further spatial analysis. It may also be used as an input to decision making systems.

Evidence that exercise-induced heat storage is dependent on adrenomedullary secretion.

PubMed

Rodrigues, A G; Lima, N R V; Coimbra, C C; Marubayashi, U

2008-06-09

To investigate the influence of medullary adrenal secretion on thermoregulation during exercise, Phy (Eserine, 5x10(-3) M) was injected into the lateral cerebral ventricle of normal (INT) or bilaterally adrenodemedullated (ADM) untrained rats. Body temperature (Tb) and metabolic rate were measured in the rats while they were exercising on a treadmill (20 m min(-1), 5% inclination) until fatigue or while they were at rest after drug injection. In resting rats, Phy increased oxygen consumption in both INT or ADM rats without any effect on core temperature. During the dynamic phase of exercise (first 20 min), ADM attenuated the exercise-induced increase in core temperature (0.86+/-0.12 degrees C ADM Sal vs 1.48+/-0.21 degrees C INT Sal), thus reducing heat storage (HS) levels. Icv injection of Phy in ADM rats significantly reduced the increase in Tb (0.012+/-0.10 degrees C min(-1) Phy vs 0.042+/-0.006 degrees C min(-1) Sal; p<0.02) and HS (65.8+/-56.1 cal Phy vs 207.7+/-32.7 cal Sal; p<0.04) compared to ADM Sal rats. In conclusion, the exercise-induced increase in heat storage was attenuated by adrenodemedullation in rats. Furthermore, the activation of heat loss mechanisms by the central cholinergic system during exercise occurs independently of adrenal medullary secretion suppression and can be improved by previous adrenodemedullation. Our data indicate the existence of a dual mechanism of heat loss control during the dynamic phase of exercise: one involving sympathoadrenal system activation that impairs heat loss and another that counteracts the increased sympathoadrenal activity through the hypothalamic cholinergic system to promote heat loss.

Patellar tendon rupture repair using Dall-Miles cable.

PubMed

Shelbourne, K D; Darmelio, M P; Klootwyk, T E

2001-01-01

Ten patients underwent patellar tendon repair with end-to-end suture technique and medial and lateral retinacular repair, as well as reinforcement with a Dall-Miles cable through the patella and tibial tubercle. The cable was tensioned at 60 degrees of flexion to allow immediate range of motion to at least 100 degrees of flexion and to protect the repair from undue tension while healing. Accurate tendon length was obtained from a lateral radiograph of the noninvolved knee in 60 degrees of flexion. Patients were allowed to bear full weight as tolerated postoperatively. A knee immobilizer was worn for approximately 2 weeks when adequate muscular control of the leg was attained. The cable was removed 6-8 weeks postoperatively, at which time range of motion equal to the opposite extremity was sought. Full extension was obtained by 1 week postoperatively. Average postoperative knee flexion was 88 degrees at 2 weeks, 112 degrees at 1 month, 133 at 3 months, and 138 degrees at 6 months compared to flexion of 141 degrees in the noninvolved knee. Mean quadriceps muscle strength 1 year postoperatively was 72%+/-11% of the noninvolved leg. No patient had patella infera or rerupture after surgery. Repair of a patellar tendon rupture with end-to-end techniques reinforced with a Dall-Miles cable allows immediate rehabilitation without the need for prolonged immobilization. This technique allows restoration of full range of motion early postoperatively and enables patients to regain adequate quadriceps strength.

Recent results on the neutron irradiation of ITER candidate copper alloys irradiated in DR-3 at 250{degrees}C to 0.3 dpa

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

Edwards, D.J.; Singh, B.N.; Toft, P.

1997-04-01

Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing and bonding thermal treatment with additional specimens re-aged and given a reactor bakeout treatment at 350{degrees}C for 100 h. CuAl-25 was also heat treated to simulate the effects of a bonding thermal cycle on the material. A number of heat treated specimens were neutron irradiated at 250{degrees}C to a dose level of {approximately}0.3 dpa in the DR-3 reactor as Riso. The main effect of the bonding thermal cycle heat treatment was a slight decrease in strength of CuCrZr and CuNiBe alloys. The strengthmore » of CuAl-25, on the other hand, remained almost unaltered. The post irradiation tests at 250{degrees}C showed a severe loss of ductility in the case of the CuNiBe alloy. The irradiated CuAl-25 and CuCrZr specimens exhibited a reasonable amount of uniform elongation, with CuCrZr possessing a lower strength.« less

Sol-gel derived fluor-hydroxyapatite biocoatings on zirconia substrate.

PubMed

Kim, Hae-Won; Kong, Young-Min; Bae, Chang-Jun; Noh, Yoon-Jung; Kim, Hyoun-Ee

2004-07-01

Fluor-hydroxyapatite (FHA) film was coated on a zirconia (ZrO(2)) substrate by a sol-gel method. An appropriate amount of F ions was incorporated into the hydroxyapatite (HA) during the preparation of the sols. The apatite phase began to crystallize after heat treatment at 400 degrees C, and increased in intensity above 500 degrees C. No decomposition was detected by X-ray diffraction analyses up to 800 degrees C, which illustrates the high thermal stability of the FHA films. The films showed a uniform and dense morphology with a thickness of approximately 1 microm after a precisely controlled heat treatment process. These FHA films adhered firmly to the zirconia substrate, representing notable adhesion strengths of approximately 70 MPa after heat treatment above 500 degrees C. The dissolution rate of the FHA coating layer varied according to the heat treatment temperature, which was closely related to the film crystallinity. The dissolution rate of the FHA film was lower than that of the HA film, suggesting the possibility of a functional gradient coating of HA and FHA. The MG63 cells seeded onto the FHA films proliferated in a similar manner to those seeded onto pure HA ceramic and a plastic control.

Effects of exercise and heat stress on regional blood flow in pregnant sheep.

PubMed

Bell, A W; Hales, J R; Fawcett, A A; King, R B

1986-05-01

Radioactive microspheres were used to measure cardiac output and blood flow to most major tissues, including those in the pregnant uterus, in late-pregnant ewes at rest and during treadmill exercise (approximately 3-fold increase in metabolic rate for 30 min) in thermoneutral (TN) (dry bulb temperature (Tdb) = 13 degrees C, wet bulb temperature (Twb) = 10 degrees C) and mildly hot (MH) (Tdb = 40 degrees C, Twb = 27 degrees C) environments. Exercise caused major increases in blood flow to respiratory muscles, nonrespiratory limb muscles, and adipose tissue, and flow was decreased to some gastrointestinal tissues, spleen, pancreas, and to placental and nonplacental tissues in the pregnant uterus. Heat exposure had relatively little effect on these exercise-induced changes, except that flow was further increased in the respiratory muscles. Results are compared with those of a similar study on nonpregnant sheep in which changes in muscle, skin, and visceral flows during exercise were attenuated by heat exposure. It is suggested that redistribution of blood flow from the pregnant uterus, which in resting ewes took 22% of cardiac output, is a significant buffer against the potentially deleterious effects of combined exercise and heat stress on blood flow to exercising muscles and thermoregulatory tissues.

Effects of interstitial heating on the RIF-1 tumor using an Nd:YAG laser with multiple fibers.

PubMed

Tobin, K M; Waldow, S M

1996-01-01

Hyperthermia was induced in tumor-bearing C3H mice using a Nd:YAG laser emitting near-infrared radiation at 1,064 nm. The efficacy of multiple implanted fiberoptics in the control of the RIF-1 tumor was investigated. RIF-1 tumors in the right hind leg were heated interstitially at 42, 44, or 46 degrees C for 30 or 60 minutes. Two, three, or four 400-microns quartz fibers terminating in a 1.0-cm cylindrical diffusor were inserted into each tumor, as were five microthermocouples to monitor temperature during treatment. Laser Doppler Flow (LDF) was also recorded pre- and post-treatment to determine changes in red blood cell flux in overlying skin (42, 44, or 46 degrees C) and the center of the tumor (46 degrees C). These experiments indicated that interstitial heating at 42, 44, and 46 degrees C resulted in tumor growth delay, although long-term control of tumors was not achieved. Treatment using four fibers resulted in the greatest tumor growth delay at 42 and 44 degrees C, increasing tumor doubling time by 50% or greater compared to control tumors; tumor growth delay following 46 degrees C treatments was seven times greater than that in control tumors. Significant changes (decreases) in LDF (P < .05) were seen in four treatment groups, using two fibers at 42 degrees C for 30 minutes, four fibers at 44 and 46 degrees C for 60 minutes on the overlying skin, and 46 degrees C for 60 minutes in the center of the tumor. Initial data indicate that interstitial heating with multiple fibers increases tumor growth delay compared to previous single fiber treatments, with tumor growth delay increasing with increasing treatment temperature; however, long-term tumor control was not achieved under the conditions investigated. Follow-up studies will explore the use of higher temperatures and/or longer treatment times in order to optimize tumor response.

Radiofrequency tissue ablation of the inferior turbinates using a thermocouple feedback electrode.

PubMed

Smith, T L; Correa, A J; Kuo, T; Reinisch, L

1999-11-01

The objective of this clinical trial was to assess the safety and efficacy of radiofrequency (RF) tissue ablation of the inferior turbinates in the treatment of nasal obstruction using an RF energy delivery system with a thermocouple feedback electrode. A prospective, nonrandomized study of 11 patients (mean age, 47+/-12 y) with chronic nasal obstruction was conducted. Using patient-based visual analogue scales (VAS), symptom parameters were assessed. These included degree of nasal obstruction, frequency of nasal obstruction, and pain. Physician assessment of nasal obstruction was also collected by the principal investigator. Follow-up was conducted at 24 hours, 1 week, 4 weeks, 8 weeks, and 1 year. ANOVA was carried out to determine statistically significant differences in the data. Data were fit to a regression model, and confidence intervals were determined from a 95% confidence level. In patient-assessed degree of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.001, P<.0001, and P<.0008, respectively). There was no difference between 8 weeks and 1 year (P<.15). The data appeared to follow an exponential decay to a constant value. The pretreatment baseline average degree of obstruction was 7.5+/-0.5 on a scale of 0 to 10. The degree of obstruction after 8 weeks was 2.7+/-0.6. The time constant for this change was 21 days to reach 90% of the final value. At 1 year, degree of obstruction was 3.3+/-0.7. For frequency of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.0001, P<.0001, and P<.0001, respectively). There was no difference between 8 weeks and 1 year (P<.15). The pretreatment baseline average frequency of obstruction was 7.8+/-0.5. The remaining frequency of obstruction after 8 weeks was 2.9+/-0.6. The time constant was 18 days. At 1 year, frequency of obstruction was 3.3+/-0.6. Physician assessment of nasal obstruction revealed statistical significance among baseline and 4 weeks, and baseline and 8 weeks (P<.0055 and P<.0056, respectively). There was no difference between 4 weeks and 8 weeks (P<.24). The average initial obstruction was 83%+/-4%. The remaining obstruction after 8 weeks was 58% +/-5%. The time constant was 14 days. Mild pain was reported by 55% of patients during the procedure; the remaining 45% reported no pain. Only one patient required pain medication consisting of acetaminophen after the procedure. There were no significant complications. Degree and frequency of nasal obstruction, as reported by patients, decreased following RF tissue ablation of the inferior turbinates. This improvement in symptoms was still evident after 1 year (P<.001). Physician assessment of obstruction also correlated with patient reports for the initial 8-week study period. The procedure was safe and well tolerated. Thermocouples within the active electrode provided additional feedback to the operating surgeon allowing the use of relatively lower tissue temperatures, power, and energy as compared with traditional techniques. These results support the need for continued research to evaluate this modality as a treatment for chronic nasal obstruction.

Vacuum Strength of Two Candidate Glasses for a Space Observatory

NASA Technical Reports Server (NTRS)

Manning, Timothy Andrew; Tucker, Dennis S.; Herren, Kenneth A.; Gregory, Don A.

2007-01-01

The strengths of two candidate glass types for use in a space observatory were measured. Samples of ultra-low expansion glass (ULE) and borosilicate (Pyrex) were tested in air and in vacuum at room temperature (20 degrees C) and in vacuum after being heated to 200 degrees C. Both glasses tested in vacuum showed a significant increase in strength over those tested in air. However, there was no statistical difference between the strength of samples tested in vacuum at room temperature and those tested in vacuum after heating to 200 degrees C.

Metal glass vacuum tube solar collectors are approaching lower-medium temperature heat application.

PubMed

Jiang, Xinian

2010-04-26

Solar thermal collectors are widely used worldwide mainly for hot water preparation at a low temperature (less than 80 degrees C). Applications including many industrial processes and central air conditioning with absorption chillers, instead require lower-medium temperature heat (between 90 degrees C and 150 degrees C) to be driven when using solar thermal energy. The metal absorber glass vacuum tube collectors (MGVT) are developed for this type of applications. Current state-of-art and possible future technology development of MGVT are presented.

Toward a new < 250 °C pyrrhotite-magnetite geothermometer for claystones

NASA Astrophysics Data System (ADS)

Aubourg, Charles; Pozzi, Jean-Pierre

2010-05-01

We investigate the effects of burial and moderate experimental heating on claystones from three regions with different degrees of maturation: immature (burial temperature ˜ 40 °C) of Bure Callovo-Oxfordian claystones in the Basin of Paris (France); early mature (burial temperature ˜ 85 °C) of Opalinus Lower Dogger claystones from the Mont Terri anticline in front of the Jura fold belt (Switzerland); and mature to overmature (burial temperature < 170 °C) of Chartreuse Callovian-Oxfordian claystones from Chartreuse Sub-Alpine chains. To have information about the nature of the magnetic assemblage, we perform low-temperature (10 K-300 K) investigation of an isothermal remanent magnetization. In a first set of laboratory heating experiments, we aim to impart a chemical remanent magnetization (CRM) at 95 °C for several weeks in Bure and Opalinus claystones. Thermal demagnetization of the CRM reveals that magnetite is formed by heating the Opalinus claystones while an assemblage of magnetite and iron sulphide is formed in Bure claystones. Further, we document the appearance of a magnetic transition at ˜ 35 K in Bure claystones after heating. We name this transition the P-transition and we propose that it is related to the formation of fine-grained pyrrhotite (Fe 7S 8). The P-transition is also detected in early mature to mature Opalinus and Chartreuse claystones. We conduct additional experimental heating of natural Opalinus claystones. One set of experiments is referred to as short-term heating (1 h) from 100 °C to 200 °C. It is dedicated to an investigation of the effect of short-lived heating processes in geology. A second set of heating experiments is designed to approach burial conditions using a gold capsule. In burial-like experiments, we heated Opalinus claystones from 150 °C to 250 °C for several weeks under a pressure of 100 MPa. In both experiments, we observe a correlative diminution of the pyrrhotite signature at 35 K with increasing temperature. We interpret this trend as the appearance of magnetite. We derive a parameter PM from the warming curve of a saturated isothermal remanent magnetization acquired at 10 K (ZFC). We report on a consistent evolution of PM with temperature in the range of 40 °C to 250 °C, including natural samples, heated samples at 95 °C, and burial-like heated samples. PM first increases between ˜ 40 °C up to ˜ 85 °C, implying that pyrrhotite gradually dominates the magnetic assemblage at low temperature. For temperatures above 85 °C, PM decreases up to 250 °C, implying that the formation of magnetite gradually overshadows the magnetic input of pyrrhotite. PM values obtained from mature to overmature claystones from the Chartreuse are lower than the PM values obtained from the burial-like heated Opalinus claystones, suggesting that the formation of magnetite is driven by kinetics. The continuous trend of the PM parameter suggests that the magnetic properties of pyrrhotite-magnetite claystones can be used to infer paleo-temperatures and we propose to name this geothermometer MagEval.

Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system.

PubMed Central

Muraca, P; Stout, J E; Yu, V L

1987-01-01

Nosocomial Legionnaires disease can be acquired by exposure to the organism from the hospital water distribution system. As a result, many hospitals have instituted eradication procedures, including hypercholorination and thermal eradication. We compared the efficacy of ozonation, UV light, hyperchlorination, and heat eradication using a model plumbing system constructed of copper piping, brass spigots, Plexiglas reservoir, electric hot water tank, and a pump. Legionella pneumophila was added to the system at 10(7) CFU/ml. Each method was tested under three conditions; (i) nonturbid water at 25 degrees C, (ii) turbid water at 25 degrees C, and (iii) nonturbid water at 43 degrees C. UV light and heat killed L. pneumophila most rapidly and required minimal maintenance. Both UV light and heat (60 degrees C) produced a 5 log kill in less than 1 h. In contrast, both chlorine and ozone required 5 h of exposure to produce a 5 log decrease. Neither turbidity nor the higher temperature of 43 degrees C impaired the efficacy of any of the disinfectant methods. Surprisingly, higher temperature enhanced the disinfecting efficacy of chlorine. However, higher temperature accelerated the decomposition of the chlorine residual such that an additional 120% volume of chlorine was required. All four methods proved efficacious in eradicating L. pneumophila from a model plumbing system. Images PMID:3566272

Development of computer models for correlating data of film cooling of nose cone under hypersonic flow

NASA Technical Reports Server (NTRS)

Sharpe, L., Jr.

1987-01-01

A 12.5 degree half cone with tangential slot injection at Mach 6.95 was studied to determine the heating rates to the surface of the body near and far downstream of the slot. The cone had a zero degree angle of attack. The heating rates were obtained using a computer program that was developed at NASA-Langley Research Center. The concentration of nitrogen from the slot into the boundary layer was also determined. The ratio of slot to freestream was varied to determine its effect on heating. The numerical heating rates were compared to other correlations obtained from experimental studies as well as theoretical laminar and turbulent results.

Developmentally regulated expression of APG-1, a member of heat shock protein 110 family in murine male germ cells.

PubMed

Kaneko, Y; Kimura, T; Nishiyama, H; Noda, Y; Fujita, J

1997-04-07

Apg-1 encodes a heat shock protein belonging to the heat shock protein 110 family, and is inducible by a 32 degrees C to 39 degrees C heat shock. Northern blot analysis of the testis from immature and adult mice, and of the purified germ cells revealed the quantitative change of the apg-1 transcripts during germ cell development. By in situ hybridization histochemistry the expressions of the apg-1 transcripts were detected in germ cells at specific stages of development including spermatocytes and spermatids. Although heat-induction of the apg-1 transcripts was observed in W/Wv mutant testis lacking germ cells, it was not detected in wild-type testis nor in the purified germ cells. Thus, the apg-1 expression is not heat-regulated but developmentally regulated in germ cells, suggesting that APG-1 plays a role in normal development of germ cells.

Experiments on the heat-induced salt balance changes in cow's milk.

PubMed

Pouliot, Y; Boulet, M; Paquin, P

1989-01-01

The heat-induced changes in salt balance between the colloidal phase of milk and its serum were studied using an ultrafiltration technique. Milk permeate was isolated at the heating temperature by means of a hollow fibre ultrafiltration cartridge coupled with a stainless steel heat exchanger unit. The milk samples initially at 4 degrees C were heated to 20, 40, 60, 80 or 90 degrees C. Ca, P, Mg and citrate contents of the permeates were determined. The decreases in Ca and P were proportional to the increase in temperature. Smaller losses in Mg and citrate were observed. An initial sharp decrease in concentration occurred within the first seconds of holding time and was followed by a slower and smaller decrease. The possible occurrence of a two-stage mechanism for the heat-induced salt precipitation is discussed. The precipitation of dicalcium phosphate is believed to occur together with some tricalcium citrate precipitation.

Effect of recent popularity on heat-conduction based recommendation models

NASA Astrophysics Data System (ADS)

Li, Wen-Jun; Dong, Qiang; Shi, Yang-Bo; Fu, Yan; He, Jia-Lin

2017-05-01

Accuracy and diversity are two important measures in evaluating the performance of recommender systems. It has been demonstrated that the recommendation model inspired by the heat conduction process has high diversity yet low accuracy. Many variants have been introduced to improve the accuracy while keeping high diversity, most of which regard the current node-degree of an item as its popularity. However in this way, a few outdated items of large degree may be recommended to an enormous number of users. In this paper, we take the recent popularity (recently increased item degrees) into account in the heat-conduction based methods, and propose accordingly the improved recommendation models. Experimental results on two benchmark data sets show that the accuracy can be largely improved while keeping the high diversity compared with the original models.

Thermal insulation of young calves exposed to cold.

PubMed Central

Rawson, R E; Dziuk, H E; Good, A L; Anderson, J F; Bates, D W; Ruth, G R

1989-01-01

Tissue, external and whole animal insulation values were determined for 12 newborn male Holstein calves continuously housed for two weeks in hutches within environmental chambers in which temperature was maintained at a constant 17 degrees C (three calves) or cycled on a daily basis either between -20 degrees and -8 degrees C (three calves) or between -30 degrees and -18 degrees C (six calves). Three of the six calves at the coldest temperature were outfitted with an insulated coat. The insulated coat provided calves a 52% increase in total insulation. Tissue insulation of cold-housed calves increased 37.2% over the first two weeks of life. It was concluded that the capacity for vasoconstriction improved with age. External insulation did not change significantly except during the first week in cold-housed calves without insulated coats. External insulation values were five to eight times those of tissue insulation values for all treatment groups. This indicated that insulation of structures external to the skin (hair, bedding, ground, etc.) provided most of the insulation for calves. PMID:2766147

Assessment of the Impact of the 2003 and 2006 Heat Waves on Cattle Mortality in France

PubMed Central

Morignat, Eric; Perrin, Jean-Baptiste; Gay, Emilie; Vinard, Jean-Luc; Calavas, Didier; Hénaux, Viviane

2014-01-01

Objectives While several studies have highlighted and quantified human mortality during the major heat waves that struck Western Europe in 2003 and 2006, the impact on farm animals has been overlooked. The aim of this study was to assess the effect of these two events on cattle mortality in France, one of the most severely impacted countries. Methods Poisson regressions were used to model the national baseline for cattle mortality between 2004 and 2005 and predict the weekly number of expected deaths in 2003 and 2006 for the whole cattle population and by subpopulation based on age and type of production. Observed and estimated values were compared to identify and quantify excess mortality. The same approach was used at a departmental scale (a French department being an administrative and territorial division) to assess the spatio-temporal evolution of the mortality pattern. Results Overall, the models estimated relative excess mortality of 24% [95% confidence interval: 22–25%] for the two-week heat wave of 2003, and 12% [11–14%] for the three-week heat wave of 2006. In 2003, most cattle subpopulations were impacted during the heat wave and some in the following weeks too. In 2006, cattle subpopulations were impacted for a limited time only, with no excess mortality at the beginning or after the heat wave. No marked differences in cattle mortality were found among the different subpopulations by age and type of production. The implications of these results for risk prevention are discussed. PMID:24667835

Thermal immobilization of Cr, Cu and Zn of galvanizing wastes in the presence of clay and fly ash.

PubMed

Singh, I B; Chaturvedi, K; Yegneswaran, A H

2007-07-01

In the present investigation thermal treatment of galvanizing waste with clay and fly ash has been carried out to immobilize Cr, Zn, Cu and other metals of the waste at temperature range 850 degrees C to 950 degrees C. Leaching of the metals from the waste and solidified product was analyzed using toxic characteristic leaching procedure (TCLP). Results indicated that the composition of waste and clay treatment temperature are the key factors in determining the stability of solidified product. After heating at 950 degrees C, the solidified specimens of 10% waste with clay have shown comparatively a high compressive strength and less water absorption. However, a decrease in compressive strength and increase in water absorption were noticed after addition of 15% of waste with clay. The leachability of all the metals present in the waste was found to reduce considerably with the increase of treatment temperature. In the case of Cr and Zn, their leachabilty was found at unacceptable levels from the treated product obtained after heating at 850 degrees C However, their leachability was reduced significantly within an acceptable level after treatment at 950 degrees C. The thermal treatment has shown an increase of re-oxidation trend of Cr (III) to Cr (VI) up to 900 degrees C of heating and this trend became almost zero after heating at 950 degrees C. Addition of fly ash did not show any improvement in strength, durability and leachability of metals from the thermally treated product. X-ray diffraction (XRD) analysis of the product confirmed the presence of mixed phases of oxides of toxic metals.

Computer modeling of the combined effects of perfusion, electrical conductivity, and thermal conductivity on tissue heating patterns in radiofrequency tumor ablation.

PubMed

Ahmed, Muneeb; Liu, Zhengjun; Humphries, Stanley; Goldberg, S Nahum

2008-11-01

To use an established computer simulation model of radiofrequency (RF) ablation to characterize the combined effects of varying perfusion, and electrical and thermal conductivity on RF heating. Two-compartment computer simulation of RF heating using 2-D and 3-D finite element analysis (ETherm) was performed in three phases (n = 88 matrices, 144 data points each). In each phase, RF application was systematically modeled on a clinically relevant template of application parameters (i.e., varying tumor and surrounding tissue perfusion: 0-5 kg/m(3)-s) for internally cooled 3 cm single and 2.5 cm cluster electrodes for tumor diameters ranging from 2-5 cm, and RF application times (6-20 min). In the first phase, outer thermal conductivity was changed to reflect three common clinical scenarios: soft tissue, fat, and ascites (0.5, 0.23, and 0.7 W/m- degrees C, respectively). In the second phase, electrical conductivity was changed to reflect different tumor electrical conductivities (0.5 and 4.0 S/m, representing soft tissue and adjuvant saline injection, respectively) and background electrical conductivity representing soft tissue, lung, and kidney (0.5, 0.1, and 3.3 S/m, respectively). In the third phase, the best and worst combinations of electrical and thermal conductivity characteristics were modeled in combination. Tissue heating patterns and the time required to heat the entire tumor +/-a 5 mm margin to >50 degrees C were assessed. Increasing background tissue thermal conductivity increases the time required to achieve a 50 degrees C isotherm for all tumor sizes and electrode types, but enabled ablation of a given tumor size at higher tissue perfusions. An inner thermal conductivity equivalent to soft tissue (0.5 W/m- degrees C) surrounded by fat (0.23 W/m- degrees C) permitted the greatest degree of tumor heating in the shortest time, while soft tissue surrounded by ascites (0.7 W/m- degrees C) took longer to achieve the 50 degrees C isotherm, and complete ablation could not be achieved at higher inner/outer perfusions (>4 kg/m(3)-s). For varied electrical conductivities in the setting of varied perfusion, greatest RF heating occurred for inner electrical conductivities simulating injection of saline around the electrode with an outer electrical conductivity of soft tissue, and the least amount of heating occurring while simulating renal cell carcinoma in normal kidney. Characterization of these scenarios demonstrated the role of electrical and thermal conductivity interactions, with the greatest differences in effect seen in the 3-4 cm tumor range, as almost all 2 cm tumors and almost no 5 cm tumors could be treated. Optimal combinations of thermal and electrical conductivity can partially negate the effect of perfusion. For clinically relevant tumor sizes, thermal and electrical conductivity impact which tumors can be successfully ablated even in the setting of almost non-existent perfusion.

Humidification during high-frequency oscillation ventilation is affected by ventilator circuit and ventilatory setting.

PubMed

Chikata, Yusuke; Imanaka, Hideaki; Onishi, Yoshiaki; Ueta, Masahiko; Nishimura, Masaji

2009-08-01

High-frequency oscillation ventilation (HFOV) is an accepted ventilatory mode for acute respiratory failure in neonates. As conventional mechanical ventilation, inspiratory gas humidification is essential. However, humidification during HFOV has not been clarified. In this bench study, we evaluated humidification during HFOV in the open circumstance of ICU. Our hypothesis is that humidification during HFOV is affected by circuit design and ventilatory settings. We connected a ventilator with HFOV mode to a neonatal lung model that was placed in an infant incubator set at 37 degrees C. We set a heated humidifier (Fisher & Paykel) to obtain 37 degrees C at the chamber outlet and 40 degrees C at the distal temperature probe. We measured absolute humidity and temperature at the Y-piece using a rapid-response hygrometer. We evaluated two types of ventilator circuit: a circuit with inner heating wire and another with embedded heating element. In addition, we evaluated three lengths of the inspiratory limb, three stroke volumes, three frequencies, and three mean airway pressures. The circuit with embedded heating element provided significantly higher absolute humidity and temperature than one with inner heating wire. As an extended tube lacking a heating wire was shorter, absolute humidity and temperature became higher. In the circuit with inner heating wire, absolute humidity and temperature increased as stroke volume increased. Humidification during HFOV is affected by circuit design and ventilatory settings.

Head insulation and heat loss in naked and clothed newborns using a thermal mannequin.

PubMed

Elabbassi, Elmountacer Billah; Chardon, Karen; Bach, Véronique; Telliez, Frédéric; Delanaud, Stéphane; Libert, Jean-Pierre

2002-06-01

In newborns, large amounts of heat are lost from the head, due to its high skin surface area. Insulating the head (for example, with a hat or bonnet) can be a simple and effective method of reducing dry heat loss. In the present study, we evaluated the safety aspects of insulating the head of low-birth-weight naked or clothed newborns by using a heated mannequin that simulates a low-birth-weight newborn. Experimental conditions (comprising a nude and three clothed setups) were performed in a closed incubator at three different air temperatures (29 degrees C, 32 degrees C, and 34 degrees C) and with and without the head being covered with a bonnet in each case, i.e., 24 experimental conditions in all. The study shows that added clothing elements and insulating the head decreases the total heat loss of the mannequin as a whole. As regards the dry heat exchange from the head, wearing a bonnet decreases the local heat loss by an average of 18.9% in all clothed and thermal conditions. This phenomenon could be at the origin of brain overheating in heavily dressed newborns, when unrestricted heat loss is limited to the face only. Our results suggest that--apart from accidental hypothermia-in order to achieve thermal equilibrium of the body, it is preferable to leave the head unprotected and to increase the level of clothing insulation over the rest of the body.

The influence of heat treatments on several types of base-metal removable partial denture alloys.

PubMed

Morris, H F; Asgar, K; Rowe, A P; Nasjleti, C E

1979-04-01

Four removable partial denture alloys, Vitallium (Co-Cr alloy), Dentillium P.D. (Fe-Cr alloy), Durallium L.G. (Co-Cr-Ni alloy), and Ticonium 100 (Ni-Cr alloy), were evaluated in the as-cast condition and after heat treatment for 15 minutes at 1,300 degrees, 1,600 degrees, 1,900 degrees, and 2,200 degrees F followed by quenching in water. The following properties were determined and compared for each alloy at each heat treatment condition: the yield strengths at 0.01%, 0.1%, and 0.2% offsets, the ultimate tensile strength, the percent elongation, the modulus of elasticity, and the Knoop microhardness. The results were statistically analyzed. Photomicrographs were examined for each alloy and test condition. The following conclusions were made: 1. The "highest values" were exhibited by the as-cast alloy. 2. Heat treatment of the partial denture alloys tested resulted in reductions in strength, while the elongations varied. This study demonstrates that, in practice, one should avoid (a) prolonged "heat-soaking" while soldering and (b) grinding or polishing of the casting until the alloy is "red hot". 3. Durallium L.G. was the least affected by the various heat treatment conditions. 4. Conventional reporting of the yield strength at 0.2% offset, the ultimate tensile strength, and percent elongation are not adequate to completely describe and compare the mechanical behavior of alloys. The reporting of the yield strength at 0.01% offset, in addition to the other reported properties, will provide a more complete description of the behavior of the dental alloys.

The effect of ethylenediaminetetraacetic acid on heat resistance and recovery of Clostridium sporogenes PA 3679 spores treated in HTST conditions.

PubMed

Silla Santos, M H; Torres Zarzo, J

1997-03-03

The effect of ethylenediaminetetraacetic acid (EDTA) on the heat resistance of Clostridium sporogenes PA 3679 spores was studied. EDTA was added to heating substrates and recovery media in order to establish which stage of the heat treatment registered the greatest EDTA activity. The heating substrates assayed were phosphate buffer (pH 7.0) and white asparagus purée, at natural pH (5.8) and acidified with citric acid and glucono-delta-lactone (GDL) to pH 5.5, 5.0 and 4.5. Recovery of survivors was carried out in MPA3679A medium in various conditions of acidification with citric and GDL (250 and 500 ppm), at pH 7.5 6.5 and 6.0. The results show greater activity of EDTA on spores when it was applied in recovery of heat injured spores, than during heating. The strongest influence of EDTA during heating was found in phosphate buffer (pH 7.0), with the effect being most evident at 121 and 126 degrees C, and in asparagus purée, at 121 degrees C and pH 5.8 rather than acidified. In recovery, the inhibiting activity of EDTA was more evident in spores subjected to more severe heat treatment, either by increasing the exposure time or by raising the temperature to 130 or 135 degrees C. The pH level of the recovery medium also affected the antimicrobial activity of EDTA, which had a greater inhibiting effect at pH 7.5 than at lower pH levels (6.5, 6.0).

Quartz crystal growth

DOEpatents

Baughman, Richard J.

1992-01-01

A process for growing single crystals from an amorphous substance that can undergo phase transformation to the crystalline state in an appropriate solvent. The process is carried out in an autoclave having a lower dissolution zone and an upper crystallization zone between which a temperature differential (.DELTA.T) is maintained at all times. The apparatus loaded with the substance, solvent, and seed crystals is heated slowly maintaining a very low .DELTA.T between the warmer lower zone and cooler upper zone until the amorphous substance is transformed to the crystalline state in the lower zone. The heating rate is then increased to maintain a large .DELTA.T sufficient to increase material transport between the zones and rapid crystallization. .alpha.-Quartz single crystal can thus be made from fused quartz in caustic solvent by heating to 350.degree. C. stepwise with a .DELTA.T of 0.25.degree.-3.degree. C., increasing the .DELTA.T to about 50.degree. C. after the fused quartz has crystallized, and maintaining these conditions until crystal growth in the upper zone is completed.

[The effect of denture base resins coated with antibacterial coating on water sorption, solubility and monomer elution].

PubMed

Yang, Yang; Gong, Hai-Huan; Song, Ai-Yang; Feng, Dan; Jin, Jie; Zhu, Song

2015-02-01

To determine the influence of denture base resins coated with antibacterial coating on water sorption, solubility and monomer elution. The values of water sorption and solubility were measured according to YY 0270-2003 and gas chromatography was used to examine the leachability of 4 commercially available heat-cured acrylic resins between experimental group and control group. Degree of crosslinking of the experimental heat-cured acrylic denture bases we remeasured by soxhlet extraction method. The data was analyzed by 17.0 software package. The values of water sorption, solubility and monomer elution of experimental group were lower compared to the control group. Degree of crosslinking of Heraeus reins was the highest among the experimental heat-cured acrylic denture bases. There is a same trend among water sorption, degree of crosslinking and the monomer elution. When the degree of crosslinking increases, the values of water sorption and monomer elution decrease. Antibacterial coating can improve the comprehensive properties of the denture base resins.

Influence of Initial Moisture Content on Heat and Moisture Transfer in Firefighters' Protective Clothing

PubMed Central

He, Song

2017-01-01

This paper presents a model for heat and moisture transfer through firefighters' protective clothing (FPC) during radiation exposure. The model, which accounts for air gaps in the FPC as well as heat transfer through human skin, investigates the effect of different initial moisture contents on the thermal insulation performance of FPC. Temperature, water vapor density, and the volume fraction of liquid water profiles were monitored during the simulation, and the heat quantity absorbed by water evaporation was calculated. Then the maximum durations of heat before the wearer acquires first- and second-degree burns were calculated based on the bioheat transfer equation and the Henriques equation. The results show that both the moisture weight in each layer and the total moisture weight increase linearly within a given environmental humidity level. The initial moisture content in FPC samples significantly influenced the maximum water vapor density. The first- and second-degree burn injury time increase 16 sec and 18 sec when the RH increases from 0% to 90%. The total quantity of heat accounted for by water evaporation was about 10% when the relative humidity (RH) is 80%. Finally, a linear relationship was identified between initial moisture content and the human skin burn injury time before suffering first- and second-degree burn injuries. PMID:28466066

Influence of Initial Moisture Content on Heat and Moisture Transfer in Firefighters' Protective Clothing.

PubMed

Huang, Dongmei; He, Song

2017-01-01

This paper presents a model for heat and moisture transfer through firefighters' protective clothing (FPC) during radiation exposure. The model, which accounts for air gaps in the FPC as well as heat transfer through human skin, investigates the effect of different initial moisture contents on the thermal insulation performance of FPC. Temperature, water vapor density, and the volume fraction of liquid water profiles were monitored during the simulation, and the heat quantity absorbed by water evaporation was calculated. Then the maximum durations of heat before the wearer acquires first- and second-degree burns were calculated based on the bioheat transfer equation and the Henriques equation. The results show that both the moisture weight in each layer and the total moisture weight increase linearly within a given environmental humidity level. The initial moisture content in FPC samples significantly influenced the maximum water vapor density. The first- and second-degree burn injury time increase 16 sec and 18 sec when the RH increases from 0% to 90%. The total quantity of heat accounted for by water evaporation was about 10% when the relative humidity (RH) is 80%. Finally, a linear relationship was identified between initial moisture content and the human skin burn injury time before suffering first- and second-degree burn injuries.

Heat transfer from high-temperature surfaces to fluids II : correlation of heat-transfer and friction data for air flowing in inconel tube with rounded entrance

NASA Technical Reports Server (NTRS)

Lowdermilk, Warren H; Grele, Milton D

1949-01-01

A heat transfer investigation, which was an extension of a previously reported NACA investigation, was conducted with air flowing through an electrically heated inconel tube with a rounded entrance,an inside diameter of 0.402 inch, and a length of 24 inches over a range of conditions, which included Reynolds numbers up to 500,000, average surface temperatures up to 2050 degrees R, and heat-flux densities up to 150,000 Btu per hour per square foot. Conventional methods of correlating heat-transfer data wherein properties of the air were evaluated at the average bulk, film, and surface temperatures resulted in reductions of Nusselt number of about 38, 46, and 53 percent, respectively, for an increase in surface temperature from 605 degrees to 2050 degrees R at constant Reynolds number. A modified correlation method in which the properties of air were based on the surface temperature and the Reynolds number was modified by substituting the product of the density at the inside tube wall and the bulk velocity for the conventional mass flow per unit cross-sectional area, resulted in a satisfactory correlation of the data for the extended ranges of conditions investigated.

Integration of dye-sensitized solar cells, thermoelectric modules and electrical storage loop system to constitute a novel photothermoelectric generator.

PubMed

Chang, Ho; Yu, Zhi-Rong

2012-08-01

This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module.

Lightweight Ceramic Insulation

NASA Technical Reports Server (NTRS)

Wheeler, W. H.; Creedon, J. F.

1986-01-01

Fiber burnout process yields low densities. Low density attained by process of sacrificial burnout. Graphite or carbon fibers mixed into slurry of silica, alumina, and boron-compound fibers in amounts ranging from 25 to 75 percent of total fiber content by weight. Mixture formed into blocks and dried. Blocks placed in kiln and heated to 1,600 degrees F(870 degrees C) for several hours. Graphite or carbon fibers slowly oxidize away, leaving voids and reducing block density. Finally, blocks heated to 2,350 degrees F (1,290 degrees C) for 90 minutes to bond remaining ceramic fibers together. Developed for use on Space Shuttle and other spacecraft, rigid insulation machined to requisite shape and bonded in place.

Carcass and meat quality traits of rabbits under heat stress.

PubMed

Zeferino, C P; Komiyama, C M; Fernandes, S; Sartori, J R; Teixeira, P S S; Moura, A S A M T

2013-03-01

Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits.

Heat activation of Phycomyces blakesleeanus spores: theromdynamics and effect of alcohols, furfural, and high pressure.

PubMed

Thevelein, J M; Van Assche, J A; Carlier, A R; Heremans, K

1979-08-01

The thermodynamic parameters for the heat activation of the sporangiospores of Phycomyces blakesleeanus were determined. For the apparent activation enthalpy (DeltaH(#)) a value of 1,151 kJ/mol was found, whereas a value of 3,644 J./ degrees K.mol was calculated for the apparent activation entropy (DeltaS(#)). n-Alcohols (from methanol to octanol), phenethyl alcohol, and furfural lowered the activation temperature of P. blakesleeanus spores. The heat resistance of the spores was lowered concomitantly. The effect of the alcohols was a linear function of the concentration in the range that could be applied. When the log of the concentration needed to produce an equal shift of the activation temperature was plotted for each alochol against the log of the octanol/water partition coefficient, a straight line was obtained. The free energy of adsorption of the n-alcohols to their active sites was calculated to be -2,487 J/mol of CH(2) groups. Although still inconclusive, this points toward an involvement of protein in the activation process. The effect of phenethyl alcohol was similar to the effect of n-alcohols, but furfural produced a greater shift than would be expected from the value of its partition coefficient. When the heat activation of the spores was performed under high pressure, the activation temperature was raised by 2 to 4 degrees K/1,000 atm. However, with pressures higher than 1,000 atm (1.013 x 10(5) kPa) the activation temperature was lowered until the pressure became lethal (more than 2,500 atm). It is known that membrane phase transition temperatures are shifted upward by about 20 degrees K/1,000 atm and that protein conformational changes are shifted upward by 2 to 6 degrees K/1,000 atm. Consequently, heat activation of fungal spores seems to be triggered by a protein conformational change and not by a membrane phase transition. Activation volumes of -54.1 cm(3)/mol at 38 degrees C and -79.3 cm(2)/mol at 40 degrees C were found for the lowering effect of high pressure on the heat activation temperature.

Acetylcholine released from cholinergic nerves contributes to cutaneous vasodilation during heat stress

NASA Technical Reports Server (NTRS)

Shibasaki, Manabu; Wilson, Thad E.; Cui, Jian; Crandall, Craig G.

2002-01-01

Nitric oxide (NO) contributes to active cutaneous vasodilation during a heat stress in humans. Given that acetylcholine is released from cholinergic nerves during whole body heating, coupled with evidence that acetylcholine causes vasodilation via NO mechanisms, it is possible that release of acetylcholine in the dermal space contributes to cutaneous vasodilation during a heat stress. To test this hypothesis, in seven subjects skin blood flow (SkBF) and sweat rate were simultaneously monitored over three microdialysis membranes placed in the dermal space of dorsal forearm skin. One membrane was perfused with the acetylcholinesterase inhibitor neostigmine (10 microM), the second membrane was perfused with the NO synthase inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME; 10 mM) dissolved in the aforementioned neostigmine solution (l-NAME(Neo)), and the third membrane was perfused with Ringer solution as a control site. Each subject was exposed to approximately 20 min of whole body heating via a water-perfused suit, which increased mean body temperature from 36.4 +/- 0.1 to 37.5 +/- 0.1 degrees C (P < 0.05). After the heat stress, SkBF at each site was normalized to its maximum value, identified by administration of 28 mM sodium nitroprusside. Mean body temperature threshold for cutaneous vasodilation was significantly lower at the neostigmine-treated site relative to the other sites (neostigmine: 36.6 +/- 0.1 degrees C, l-NAME(Neo): 37.1 +/- 0.1 degrees C, control: 36.9 +/- 0.1 degrees C), whereas no significant threshold difference was observed between the l-NAME(Neo)-treated and control sites. At the end of the heat stress, SkBF was not different between the neostigmine-treated and control sites, whereas SkBF at the l-NAME(Neo)-treated site was significantly lower than the other sites. These results suggest that acetylcholine released from cholinergic nerves is capable of modulating cutaneous vasodilation via NO synthase mechanisms early in the heat stress but not after substantial cutaneous vasodilation.

Comparison of blood pressure and thermal responses in rats exposed to millimeter wave energy or environmental heat.

PubMed

Millenbaugh, Nancy J; Kiel, Johnathan L; Ryan, Kathy L; Blystone, Robert V; Kalns, John E; Brott, Becky J; Cerna, Cesario Z; Lawrence, William S; Soza, Laura L; Mason, Patrick A

2006-06-01

Electromagnetic fields at millimeter wave lengths are being developed for commercial and military use at power levels that can cause temperature increases in the skin. Previous work suggests that sustained exposure to millimeter waves causes greater heating of skin, leading to faster induction of circulatory failure than exposure to environmental heat (EH). We tested this hypothesis in three separate experiments by comparing temperature changes in skin, subcutis, and colon, and the time to reach circulatory collapse (mean arterial blood pressure, 20 mmHg) in male Sprague-Dawley rats exposed to the following conditions that produced similar rates of body core heating within each experiment: (1) EH at 42 degrees C, 35 GHz at 75 mW/cm, or 94 GHz at 75 mW/cm under ketamine and xylazine anesthesia; (2) EH at 43 degrees C, 35 GHz at 90 mW/cm, or 94 GHz at 90 mW/cm under ketamine and xylazine anesthesia; and (3) EH at 42 degrees C, 35 GHz at 90 mW/cm, or 94 GHz at 75 mW/cm under isoflurane anesthesia. In all three experiments, the rate and amount of temperature increase at the subcutis and skin surface differed significantly in the rank order of 94 GHz more than 35 GHz more than EH. The time to reach circulatory collapse was significantly less only for rats exposed to 94 GHz at 90 mW/cm, the group with the greatest rate of skin and subcutis heating of all groups in this study, compared with both the 35 GHz at 90 mW/cm and the EH at 43 degrees C groups. These data indicate that body core heating is the major determinant of induction of hemodynamic collapse, and the influence of heating of the skin and subcutis becomes significant only when a certain threshold rate of heating of these tissues is exceeded.

Effects of heating on composition, degree of darkness, and stacking nanostructure of soil humic acids.

PubMed

Katsumi, Naoya; Yonebayashi, Koyo; Okazaki, Masanori

2016-01-15

Wildfires and prescribed burning can affect both the quality and the quantity of organic matter in soils. In this study, we investigated qualitative and quantitative changes of soil humic substances in two different soils (an Entisol from a paddy field and an Inceptisol from a cedar forest) under several controlled heating conditions. Soil samples were heated in a muffle furnace at 200, 250, or 300 °C for 1, 3, 5, or 12h. The humic acid and fulvic acid contents of the soil samples prior to and after heating were determined. The degree of darkness, elemental composition, carbon and nitrogen stable isotope ratios, (13)C nuclear magnetic resonance spectra, and X-ray diffraction patterns of humic acids extracted from the soils before and after heating were measured. The proportion of humic acids in total carbon decreased with increasing heating time at high temperature (300 °C), but increased with increasing heating time at ≤ 250 °C. The degree of darkness of the humic acids increased with increasing heating time and temperature. During darkening, the H/C atomic ratios, the proportion of aromatic C, and the carbon and nitrogen stable isotope ratios increased, whereas the proportions of alkyl C and O-alkyl C decreased. X-ray diffraction analysis verified that a stacking nanostructure developed by heating. Changes in the chemical structure of the humic acids from the heated soils depended on the type of soil. The major structural components of the humic acids from the heated Entisol were aromatic C and carboxylic C, whereas aliphatic C, aromatic C, and carboxylic C structural components were found in the humic acids from the heated Inceptisol. These results suggest that the heat-induced changes in the chemical structure of the humic acids depended on the source plant. Copyright © 2015 Elsevier B.V. All rights reserved.

Dynamic Model Investigation of Water Pressures and Accelerations Encountered During Landings of the Apollo Spacecraft

NASA Technical Reports Server (NTRS)

Stubbs, Sandy M.

1967-01-01

An experimental investigation was made to determine impact water pressures, accelerations, and landing dynamics of a 1/4-scale dynamic model of the command module of the Apollo spacecraft. A scaled-stiffness aft heat shield was used on the model to simulate the structural deflections of the full-scale heat shield. Tests were made on water to obtain impact pressure data at a simulated parachute letdown (vertical) velocity component of approximately 30 ft/sec (9.1 m/sec) full scale. Additional tests were made on water, sand, and hard clay-gravel landing surfaces at simulated vertical velocity components of 23 ft/sec (7.0 m/sec) full scale. Horizontal velocity components investigated ranged from 0 to 50 ft/sec (15 m/sec) full scale and the pitch attitudes ranged from -40 degrees to 29 degrees. Roll attitudes were O degrees, 90 degrees, and 180 degrees, and the yaw attitude was 0 degrees.

The drug release study of ceftriaxone from porous hydroxyapatite scaffolds.

PubMed

Al-Sokanee, Zeki N; Toabi, Abedl Amer H; Al-Assadi, Mohammed J; Alassadi, Erfan A S

2009-01-01

Hydroxyapatite (HAP) is an important biomedical material that is used for grafting osseous defects. It has an excellent bioactivity and biocompatibility properties. To isolate hydroxyapatite, pieces of cleaned cattle's bone were heated at different temperature range from 400 degrees C up to 1,200 degrees C. A reasonable yield of 60.32% w/w HAP was obtained at temperature range from 1,000 degrees C to 1,200 degrees C. Fourier transform infrared spectra and the thermogravimetric measurement showed a clear removal of organic at 600 degrees C as well as an excellent isolation of HAP from the bones which was achieved at 1,000-1,200 degrees C. This was also confirmed from X-ray diffraction of bone sample heated at 1,200 degrees C. The concentration ions were found to be sodium, potassium, lithium, zinc, copper, iron, calcium, magnesium, and phosphate present in bones within the acceptable limits for its role in the bioactivity property of HAP. Glucose powder was used as a porosifier. Glucose was novel and excellent as porogen where it was completely removed by heating, giving an efficient porosity in the used scaffolds. The results exhibited that the ceftriaxone drug release was increased with increasing the porosity. It was found that a faster, higher, and more regular drug release was obtained from the scaffold with a porosity of 10%.

Phase transformation changes in thermocycled nickel-titanium orthodontic wires.

PubMed

Berzins, David W; Roberts, Howard W

2010-07-01

In the oral environment, orthodontic wires will be subject to thermal fluctuations. The purpose of this study was to investigate the effect of thermocycling on nickel-titanium (NiTi) wire phase transformations. Straight segments from single 27 and 35 degrees C copper NiTi (Ormco), Sentalloy (GAC), and Nitinol Heat Activated (3M Unitek) archwires were sectioned into 5mm segments (n=20). A control group consisted of five randomly selected non-thermocycled segments. The remaining segments were thermocycled between 5 and 55 degrees C with five randomly selected segments analyzed with differential scanning calorimetry (DSC; -100<-->150 degrees C at 10 degrees C/min) after 1000, 5000, and 10,000 cycles. Thermal peaks were evaluated with results analyzed via ANOVA (alpha=0.05). Nitinol HA and Sentalloy did not demonstrate qualitative or quantitative phase transformation behavior differences. Significant differences were observed in some of the copper NiTi transformation temperatures, as well as the heating enthalpy with the 27 degrees C copper NiTi wires (p<0.05). Qualitatively, with increased thermocycling the extent of R-phase in the heating peaks decreased in the 35 degrees C copper NiTi, and an austenite to martensite peak shoulder developed during cooling in the 27 degrees C copper NiTi. Repeated temperature fluctuations may contribute to qualitative and quantitative phase transformation changes in some NiTi wires. Copyright 2010 Academy of Dental Materials. All rights reserved.

Preparation of stationary phases for reversed-phase high-performance liquid chromatography using thermal treatments at high temperature.

PubMed

Vigna, Camila R M; Bottoli, Carla B G; Collins, Kenneth E; Collins, Carol H

2007-07-13

Batches of poly(methyloctylsiloxane) (PMOS)-loaded silica were prepared by deposition from a solution of PMOS into the pores of HPLC silica. Portions of PMOS-loaded silica were subjected to a thermal treatment at 100 degrees C for 24h (condition 1) in a tube furnace under a nitrogen atmosphere. After that, the material was heated for 4h at higher temperatures (150-400 degrees C) (condition 2). Heating at higher temperatures produces polymer bilayers. Non-immobilized and thermally treated stationary phases were characterized by percent carbon, (29)Si cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy and reversed-phase chromatographic performance. The results show that thermal treatment between 150 and 300 degrees C accelerates the immobilization process, possibly due to some bond breaking of the polysiloxane, with formation of strong linkages to the surface of the support, resulting in more complete coverage of the silica. The chromatographic results show an improvement of efficiency with the increase of the temperature of condition 2 up to 300 degrees C and an increase in the resolution of the components, mainly for the phase heated at 300 degrees C. Such results demonstrate that a two-step thermal treatment (100 degrees C then 150-300 degrees C) produces stationary phases with good properties for use in reversed-phase high-performance liquid chromatography.

Changes in active ankle dorsiflexion range of motion after acute inversion ankle sprain.

PubMed

Youdas, James W; McLean, Timothy J; Krause, David A; Hollman, John H

2009-08-01

Posterior calf stretching is believed to improve active ankle dorsiflexion range of motion (AADFROM) after acute ankle-inversion sprain. To describe AADFROM at baseline (postinjury) and at 2-wk time periods for 6 wk after acute inversion sprain. Randomized trial. Sports clinic. 11 men and 11 women (age range 11-54 y) with acute inversion sprain. Standardized home exercise program for acute inversion sprain. AADFROM with the knee extended. Time main effect on AADFROM was significant (F3,57 = 108, P < .001). At baseline, mean active sagittal-plane motion of the ankle was 6 degrees of plantar flexion, whereas at 2, 4, and 6 wk AADFROM was 7 degrees, 11 degrees, and 11 degrees, respectively. AADFROM increased significantly from baseline to week 2 and from week 2 to week 4. Normal AADFROM was restored within 4 wk after acute inversion sprain.

Preparation of a non-woven poly(ε-caprolactone) fabric with partially embedded apatite surface for bone tissue engineering applications by partial surface melting of poly(ε-caprolactone) fibers.

PubMed

Kim, In Ae; Rhee, Sang-Hoon

2017-07-01

This article describes a novel method for the preparation of a biodegradable non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface designed for application as a scaffold material for bone tissue engineering. The non-woven poly(ε-caprolactone) fabric was generated by the electro-spinning technique and then apatite was coated in simulated body fluid after coating the PVA solution containing CaCl 2 ·2H 2 O. The apatite crystals were partially embedded or fully embedded into the thermoplastic poly(ε-caprolactone) fibers by controlling the degree of poly(ε-caprolactone) fiber surface melting in a convection oven. Identical apatite-coated poly(ε-caprolactone) fabric that did not undergo heat-treatment was used as a control. The features of the embedded apatite crystals were evaluated by FE-SEM, AFM, EDS, and XRD. The adhesion strengths of the coated apatite layers and the tensile strengths of the apatite coated fabrics with and without heat-treatment were assessed by the tape-test and a universal testing machine, respectively. The degree of water absorbance was assessed by adding a DMEM droplet onto the fabrics. Moreover, cell penetrability was assessed by seeding preosteoblastic MC3T3-E1 cells onto the fabrics and observing the degrees of cell penetration after 1 and 4 weeks by staining nuclei with DAPI. The non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface showed good water absorbance, cell penetrability, higher apatite adhesion strength, and higher tensile strength compared with the control fabric. These results show that the non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface is a potential candidate scaffold for bone tissue engineering due to its strong apatite adhesion strength and excellent cell penetrability. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1973-1983, 2017. © 2017 Wiley Periodicals, Inc.

Development of a High-Performance Fin-and-Tube Heat Exchanger with Vortex Generators for a Vending Machine

NASA Astrophysics Data System (ADS)

Iwasaki, Masamichi; Saito, Hiroshi; Mochizuki, Sadanari; Murata, Akira

The effect of delta-wing-vortex generators (combination of a delta wing and a delta winglet pair) on the heat transfer performance of fin-and-tube heat exchangers for vending machines has been investegated. Flow visualizations, numerical simulations and heat transfer experiments were conducted to find an optimum geometrical shape and arrangement of the vortex generators. Maximum heat transfer enhancement was achieved by the combination of (a) the delta wing with the apex angle of 86 degrees and (b) the delta winglet pair with the inline angle of 45 degrees. In relatively low Reynolds number range, about 40 % increase in heat transfer coefficient was attained with the above mentioned combination of the vortex generators compared to the ordinary heat exchangers with plain fins. It was revealed that the heat transfer enhancement was attributed to (1) the longitudinal vortexes generated by the delta wing and (2) the reduction of wake area behind the tube. It was also found that an increase in the apex angle of the delta wing brought about heat transfer enhancement, and the scale as well as the streggth of the induced longitudinal vortices played an important role in the heat transfer performance.

The effect of heat waves, elevated [CO2 ] and low soil water availability on northern red oak (Quercus rubra L.) seedlings.

PubMed

Bauweraerts, Ingvar; Wertin, Timothy M; Ameye, Maarten; McGuire, Mary Anne; Teskey, Robert O; Steppe, Kathy

2013-02-01

The frequency and intensity of heat waves are predicted to increase. This study investigates whether heat waves would have the same impact as a constant increase in temperature with the same heat sum, and whether there would be any interactive effects of elevated [CO2 ] and soil moisture content. We grew Quercus rubra seedlings in treatment chambers maintained at either ambient or elevated [CO2 ] (380 or 700 μmol CO2 mol(-1) ) with temperature treatments of ambient, ambient +3 °C, moderate heat wave (+6 °C every other week) or severe heat wave (+12 °C every fourth week) temperatures. Averaged over a 4-week period, and the entire growing season, the three elevated temperature treatments had the same average temperature and heat sum. Half the seedlings were watered to a soil water content near field capacity, half to about 50% of this value. Foliar gas exchange measurements were performed morning and afternoon (9:00 and 15:00 hours) before, during and after an applied heat wave in August 2010. Biomass accumulation was measured after five heat wave cycles. Under ambient [CO2 ] and well-watered conditions, biomass accumulation was highest in the +3 °C treatment, intermediate in the +6 °C heat wave and lowest in the +12 °C heat wave treatment. This response was mitigated by elevated [CO2 ]. Low soil moisture significantly decreased net photosynthesis (Anet ) and biomass in all [CO2 ] and temperature treatments. The +12 °C heat wave reduced afternoon Anet by 23% in ambient [CO2 ]. Although this reduction was relatively greater under elevated [CO2 ], Anet values during this heat wave were still 34% higher than under ambient [CO2 ]. We concluded that heat waves affected biomass growth differently than the same amount of heat applied uniformly over the growing season, and that the plant response to heat waves also depends on [CO2 ] and soil moisture conditions. © 2012 Blackwell Publishing Ltd.

Proximal metatarsal osteotomy for hallux valgus: an audit of radiologic outcome after single screw fixation and full postoperative weightbearing

PubMed Central

2013-01-01

Background Proximal metatarsal osteotomy combined with a distal soft-tissue procedure is a common treatment for moderate to severe hallux valgus. Secure stabilisation of the metatarsal osteotomy is necessary to avoid complications such as delayed union, nonunion or malunion as well as loss of correction. The aim of this study was to report our results using a single screw for stabilisation of the osteotomy. Methods We retrospectively reviewed 151 patients with severe hallux valgus who were treated by the above mentioned way with full postoperative weightbearing in a stiff soled shoe. Mean age of patients at time of surgery was 54 years, 19 patients were male and 132 female. Assessment of clinical and radiographic results was performed after 2 days and 6 weeks. Results were also correlated to the experience of the performing surgeon. Results Mean preoperative HVA (hallux valgus angle) was 36.4 degrees, and then 3.5 degrees 2 days and 13.4 degrees 6 weeks after the procedure (p < 0.001). Mean preoperative IMA (intermetarsal angle) was 16.8 degrees, and then 6.4 degrees after 2 days and 9.8 degrees after 6 weeks (p < 0.001). Mean preoperative first metatarsal length of 56.4 mm decreased to 53.6 mm after 6 weeks. Possible non-union of the osteotomy was observed in 4 patients (2.6%) after 6 weeks. Performing residents (n = 40) operated in 65 minutes and attending surgeons (n = 111) in 45 minutes, with no significant differences in radiographic measurements between both groups. Conclusions Single screw stabilisation of proximal chevron osteotomy is a reliable method for treating severe hallux valgus deformities with satisfactory results. PMID:23725485

Approximate heating analysis for the windward-symmetry plane of Shuttle-like bodies at large angle of attack

NASA Technical Reports Server (NTRS)

Zoby, E. V.

1981-01-01

An engineering method has been developed for computing the windward-symmetry plane convective heat-transfer rates on Shuttle-like vehicles at large angles of attack. The engineering code includes an approximate inviscid flowfield technique, laminar and turbulent heating-rate expressions, an approximation to account for the variable-entropy effects on the surface heating and the concept of an equivalent axisymmetric body to model the windward-ray flowfields of Shuttle-like vehicles at angles of attack from 25 to 45 degrees. The engineering method is validated by comparing computed heating results with corresponding experimental data measured on Shuttle and advanced transportation models over a wide range of flow conditions and angles of attack from 25 to 40 degrees and also with results of existing prediction techniques. The comparisons are in good agreement.

High ambient temperature increases intravenous methamphetamine self-administration on fixed and progressive ratio schedules in rats.

PubMed

Cornish, Jennifer L; Clemens, Kelly J; Thompson, Murray R; Callaghan, Paul D; Dawson, Bronwyn; McGregor, Iain S

2008-01-01

Methamphetamine is a drug that is often consumed at dance parties or nightclubs where the ambient temperature is high. The present study determined whether such high ambient temperatures alter intravenous methamphetamine self-administration in the rat. Male Hooded Wistar rats were trained to self-administer intravenous methamphetamine (0.1 mg/kg/infusion) under a fixed ratio 1 (FR1) or progressive ratio (PR) schedule of reinforcement at an ambient temperature of 23 +/- 1 degrees C. They were then given their daily self-administration session at a raised ambient temperature of 30 +/- 1 degrees C. Methamphetamine self-administration was increased at 30 degrees C under both FR1 and PR reinforcement schedules, with the latter effect indicating that heat enhances the motivation to obtain methamphetamine. High temperatures did not alter self-administration of the D1 receptor agonist SKF 82958 in methamphetamine-experienced rats suggesting some specificity in the methamphetamine effect. When rats were given access to drink isotonic saline solution during methamphetamine self-administration sessions they drank much more solution at 30 degrees C than 23 degrees C. However, availability of isotonic saline to drink did not alter the heat-induced facilitation of methamphetamine self-administration (PR schedule) indicating that the heat effect does not simply reflect increased motivation for intravenous fluids. Hyperthermia was evident in rats self-administering methamphetamine at high ambient temperatures and fluid consumption did not prevent this effect. Heat did not affect blood levels of methamphetamine, or its principal metabolite amphetamine indicating that the facilitatory effect of heat did not reflect altered methamphetamine pharmacokinetics. Overall, these results show that high ambient temperatures increase the reinforcing efficacy of methamphetamine and encourage higher levels of drug intake.

Destruction of Listeria monocytogenes in sturgeon (Acipenser transmontanus) caviar by a combination of nisin with chemical antimicrobials or moderate heat.

PubMed

Al-Holy, M; Lin, M; Rasco, B

2005-03-01

The objective of this study was to investigate the effect of nisin in combination with heat or antimicrobial chemical treatments (such as lactic acid, chlorous acid, and sodium hypochlorite) on the inhibition of Listeria monocytogenes and total mesophiles in sturgeon (Acipenser transmontanus) caviar. The effects of nisin (250, 500, 750, and 1,000 IU/ml), lactic acid (1, 2, and 3%), chlorous acid (134 and 268 ppm), sodium hypochlorite (150 and 300 ppm), and heat at 60 degrees C for 3 min were evaluated for a five-strain mixture of L. monocytogenes and total mesophiles in sturgeon caviar containing 3.5% salt. Selected combinations of these antimicrobial treatments were also tested. Injured and viable L. monocytogenes cells were recovered using an overlay method. Treating caviar with > or =500 IU/ml nisin initially reduced L. monocytogenes by 2 to 2.5 log units. Chlorous acid (268 ppm) reduced L. monocytogenes from 7.7 log units to undetectable (<0.48 log units) after 4 days of storage at 4 degrees C. However, there were no synergistic effects observed for combinations of nisin (500 or 750 IU/ml) plus either lactic acid or chlorous acid. Lactic acid caused a slight reduction (approximately 1 log unit) in the microbial load during a 6-day period at 4 degrees C. Sodium hypochlorite was ineffective at the levels tested. Mild heating (60 degrees C for 3 min) with nisin synergistically reduced viable counts of L. monocytogenes and total mesophiles. No L. monocytogenes cells (<0.48 log units) were recovered from caviar treated with heat and nisin (750 IU/ml) after a storage period of 28 days at 4 degrees C.

Thermal inactivation of the wine spoilage yeasts Dekkera/Brettanomyces.

PubMed

Couto, José António; Neves, Filipe; Campos, Francisco; Hogg, Tim

2005-10-25

The heat resistance of three strains of Dekkera/Brettanomyces (Dekkera anomala PYCC 5,153, Dekkera bruxellensis PYCC 4,801 and Dekkera/Brettanomyces 093) was evaluated at different temperatures between 32.5 and 55 degrees C. Thermal inactivation tests were performed in tartrate buffer solution (pH 4.0) and in wines. In the studies employing buffer as the heating menstruum, measurable thermal inactivation began only at temperatures of 50 degrees C. When heating was performed in wine, significant inactivation begins at 35 degrees C. Subsequent thermal inactivation tests were performed in buffer at various levels of pH, ethanol concentration, and various phenolic acids. Results from experiments in buffer with added ethanol suggest that the greater heat sensitivity shown in wines can be largely attributed to ethanol, although potentiation of this effect might be due to the phenolic content, particularly from ferulic acid. In the range of pH values tested (2.5-4.5), this factor had no influence in the heat inactivation kinetics. Relevant data, in the form of D and Z values calculated in the various environments, potentially useful for the establishment of regimes of thermal control of Dekkera/Brettanomyces yeasts in wine and contaminated equipment is presented.

Spatial distributions of heating, cooling, and industrial degree-days in Turkey

NASA Astrophysics Data System (ADS)

Yildiz, I.; Sosaoglu, B.

2007-11-01

The degree-day method is commonly used to estimate energy consumption for heating and cooling in residential, commercial and industrial buildings, as well as in greenhouses, livestock facilities, storage facilities and warehouses. This article presents monthly and yearly averages and spatial distributions of heating, cooling, and industrial degree-days at the base temperatures of 18 °C and 20 °C, 18 °C and 24 °C, and 7 °C and 13 °C, respectively; as well as the corresponding number of days in Turkey. The findings presented here will facilitate the estimation of heating and cooling energy consumption for any residential, commercial and industrial buildings in Turkey, for any period of time (monthly, seasonal, etc.). From this analysis it will also be possible to compare and design alternative building systems in terms of energy efficiencies. If one prefers to use set point temperatures to indicate the resumption of the heating season would also be possible using the provided information in this article. In addition, utility companies and manufacturing/marketing companies of HVAC systems would be able to easily determine the demand, marketing strategies and policies based on the findings in this study.

Changes in extremes due to half a degree warming in observations and models

NASA Astrophysics Data System (ADS)

Fischer, E. M.; Schleussner, C. F.; Pfleiderer, P.

2017-12-01

Assessing the climate impacts of half-a-degree warming increments is high on the post-Paris science agenda. Discriminating those effects is particularly challenging for climate extremes such as heavy precipitation and heat extremes for which model uncertainties are generally large, and for which internal variability is so important that it can easily offset or strongly amplify the forced local changes induced by half a degree warming. Despite these challenges we provide evidence for large-scale changes in the intensity and frequency of climate extremes due to half a degree warming. We first assess the difference in extreme climate indicators in observational data for the 1960s and 1970s versus the recent past, two periods differ by half a degree. We identify distinct differences for the global and continental-scale occurrence of heat and heavy precipitation extremes. We show that those observed changes in heavy precipitation and heat extremes broadly agree with simulated historical differences and are informative for the projected differences between 1.5 and 2°C warming despite different radiative forcings. We therefore argue that evidence from the observational record can inform the debate about discernible climate impacts in the light of model uncertainty by providing a conservative estimate of the implications of 0.5°C warming. A limitation of using the observational record arises from potential non-linearities in the response of climate extremes to a certain level of warming. We test for potential non-linearities in the response of heat and heavy precipitation extremes in a large ensemble of transient climate simulations. We further quantify differences between a time-window approach in a coupled model large ensemble vs. time-slice experiments using prescribed SST experiments performed in the context of the HAPPI-MIP project. Thereby we provide different lines of evidence that half a degree warming leads to substantial changes in the expected occurrence of heat and heavy precipitation extremes.

Combustion heater for oil shale

DOEpatents

Mallon, Richard G.; Walton, Otis R.; Lewis, Arthur E.; Braun, Robert L.

1985-01-01

A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

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 normal environment. These results indicate that GABA in the PO/AH is an important neurotransmitter for disinhibition of heat production and inhibition of heat loss under cold ambient temperature. It is a neurotransmitter for inhibition of heat production under hot ambient temperature.

Experimental assessment of disinfection procedures for eradication of Aspergillus fumigatus in food.

PubMed

Gangneux, Jean-Pierre; Noussair, Latifa; Bouakline, Adel; Roux, Nicole; Lacroix, Claire; Derouin, Francis

2004-10-01

Aspergillus fumigatus spores in food may represent an infectious risk for neutropenic patients. We examined the efficiency of disinfection procedures applicable to foods for eradication of A fumigatus. Boiling and microwave treatment fully decontaminated an experimental spore suspension and naturally contaminated liquid foods (reconstituted dried food, herbal tea). Full decontamination of experimentally contaminated surfaces was only obtained with 70% ethanol or heating at 220 degrees C for 15 minutes. Pepper was decontaminated when heated for 15 minutes at 220 degrees C but not by microwaving. Fruit skin was partially decontaminated by 70% ethanol. We conclude that A fumigatus spores can be eradicated from food by heating to a temperature of at least 100 degrees C. When foods cannot be exposed to high temperature or microwaving, ethanol only partially reduces the level of surface contamination.

Thermal inactivation of Salmonella and Escherichia coli O157:H7 on alfalfa seeds.

PubMed

Feng, Guoping; Churey, John J; Worobo, Randy W

2007-07-01

Alfalfa seeds inoculated with five strains of Salmonella or Escherichia coli O157:H7 were subjected to dry heat at 55 degrees C for up to 8 days. Five-log reductions in Salmonella or E. coli O157:H7 on seeds were observed. No pathogens were detected on the sprouted seeds, which were initially inoculated with ca. 2 log CFU/g of Salmonella or more than 8 log CFU/g of E. coli O157:H7. The percentages of germination of the alfalfa seeds did not significantly decrease after 6 days of heating at 55 degrees C. These results showed that heat treatment of alfalfa seeds at 55 degrees C for up to 6 days was effective in enhancing the safety of alfalfa sprouts without affecting germination significantly.

The effects of heated and room-temperature abdominal lavage solutions on core body temperature in dogs undergoing celiotomy.

PubMed

Nawrocki, Michael A; McLaughlin, Ron; Hendrix, P K

2005-01-01

To document the magnitude of temperature elevation obtained with heated lavage solutions during abdominal lavage, 18 dogs were lavaged with sterile isotonic saline intraoperatively (i.e., during a celiotomy). In nine dogs, room-temperature saline was used. In the remaining nine dogs, saline heated to 43+/-2 degrees C (110+/-4 degrees F) was used. Esophageal, rectal, and tympanic temperatures were recorded every 60 seconds for 15 minutes after initiation of the lavage. Temperature levels decreased in dogs lavaged with room-temperature saline. Temperature levels increased significantly in dogs lavaged with heated saline after 2 to 6 minutes of lavage, and temperatures continued to increase throughout the 15-minute lavage period.

Corrosion behavior of sensitized duplex stainless steel.

PubMed

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

1998-01-01

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

Shuttle Technology for Earth Laboratories

NASA Technical Reports Server (NTRS)

1987-01-01

Pyran System represents a major advancement in control of pyrolysis, the technology of subjecting organic material to selected temperatures to break them down into their component parts, and that the system offers capabilities unavailable. Pyran System is designed for rapid automated analysis of the composition of organic matter. It is capable of heating samples to 1,130 degrees fahrenheit with infrared heat at a precisely controlled atmosphere. In order to do this with the degree of control and repeatability desired, the developers of the Pyran system decided they would need a special type of material to insulate the heating chambers. They adopted the shuttle tiles for the difficult insulating job. The tiles provide superior insulating characteristics needed, and they can be readily cut and formed to fit the heating chambers.

Influence of chemical and mechanical polishing on water sorption and solubility of denture base acrylic resins.

PubMed

Rahal, Juliana Saab; Mesquita, Marcelo Ferraz; Henriques, Guilherme Elias Pessanha; Nóbilo, Mauro Antonio Arruda

2004-01-01

Influence of polishing methods on water sorption and solubility of denture base acrylic resins was studied. Eighty samples were divided into groups: Classico (CL), and QC 20 (QC) - hot water bath cured; Acron MC (AC), and Onda Cryl (ON) - microwave cured; and submitted to mechanical polishing (MP) - pumice slurry, chalk powder, soft brush and felt cone in a bench vise; or chemical polishing (CP) - heated monomer fluid in a chemical polisher. The first desiccation process was followed by storage in distilled water at 37 +/- 1 degrees C for 1 h, 1 day, 1, 2, 3 and 4 weeks. Concluding each period, water sorption was measured. After the fourth week, a second desiccation process was done to calculate solubility. Data were submitted to analysis of variance, followed by Tukey test (p

Progressive exercise preconditioning protects against circulatory shock during experimental heatstroke.

PubMed

Hung, Ching-Hsia; Chang, Nen-Chung; Cheng, Bor-Chih; Lin, Mao-Tsun

2005-05-01

Heat shock protein (HSP) 72 expression protects against arterial hypotension in rat heatstroke. HSP72 can also be induced in multiple organs, including hearts from rats with endurance exercise. We validated the hypothesis that progressive exercise preconditioning may confer cardiovascular protection during heatstroke by inducing the overexpression of HSP72 in multiple organs. To deal with the matter, we assessed the effects of heatstroke on mean arterial pressure, heart rate, cardiac output, stroke volume, total peripheral vascular resistance, colonic temperature, blood gases, and serum or tissue levels of tumor necrosis factor-alpha (TNF-alpha) in urethane-anesthetized rats pretreated without or with progressive exercise training for 1, 2, or 3 weeks. In addition, HSP72 expression in multiple organs was determined in different groups of animals. Heatstroke was induced by exposing the rats to a high blanket temperature (43 degrees C); the moment at which mean arterial pressure decreased from the peak value was taken as the time of heatstroke onset. Previous exercise training for 3 weeks, but not 1 or 2 weeks, conferred significant protection against hyperthermia, arterial hypotension, decreased cardiac output, decreased stroke volume, decreased peripheral vascular resistance, and increased levels of serum or tissue TNF-alpha during heatstroke and correlated with overexpression of HSP72 in multiple organs, including heart, liver, and adrenal gland. However, 10 days after 3 weeks of progressive exercise training, when HSP72 expression in multiple organs returned to basal values, the beneficial effects exerted by 3 weeks of exercise training were no longer observed. These results strongly suggest that HSP72 preconditioning with progressive exercise training protects against hyperthermia, circulatory shock, and TNF-alpha overproduction during heatstroke.

Inhibition of Listeria monocytogenes by Lactobacillus bavaricus MN in beef systems at refrigeration temperatures.

PubMed Central

Winkowski, K; Crandall, A D; Montville, T J

1993-01-01

The ability of Lactobacillus bavaricus, a meat isolate, to inhibit the growth of three Listeria monocytogenes strains was examined in three beef systems: beef cubes, beef cubes in gravy, and beef cubes in gravy containing glucose. The beef was minimally heat treated, inoculated with L. bavaricus at 10(5) or 10(3) CFU/g and L. monocytogenes at 10(2) CFU/g, vacuum sealed, and stored at 4 or 10 degrees C. The meat samples were monitored for microbial growth, pH, and bacteriocin production. The pathogen was inhibited by L. bavaricus MN. At 4 degrees C, L. monocytogenes was inhibited or killed depending on the initial inoculum level of L. bavaricus. At 10 degrees C, at least a 10-fold reduction of the pathogen occurred, except in the beef without gravy. This system showed a transient inhibition of the pathogen during the first week of storage followed by growth to control levels by the end of the incubation period. Bacteriocin was detected in the samples, and inhibition could not be attributed to acidification. Low refrigeration temperatures significantly (P < or = 0.05) enhanced L. monocytogenes inhibition. Moreover, the addition of glucose-containing gravy and the higher inoculum level of L. bavaricus were significantly (P < or = 0.05) more effective in reducing L. monocytogenes populations in most of the systems studied. PMID:8368843

Quinoa starch granules as stabilizing particles for production of Pickering emulsions.

PubMed

Rayner, Marilyn; Sjöö, Malin; Timgren, Anna; Dejmek, Petr

2012-01-01

Intact starch granules isolated from quinoa (Chenopodium quinoa Willd.) were used to stabilize emulsion drops in so-called Pickering emulsions. Miglyol 812 was used as dispersed phase and a phosphate buffer (pH7) with different salt (NaCl) concentrations was used as the continuous phase. The starch granules were hydrophobically modified to different degrees by octenyl succinic anhydride (OSA) or by dry heat treatment at 120 degrees C in order to study the effect on the resulting emulsion drop size. The degree of OSA-modification had a low to moderate impact on drop size. The highest level of modification (4.66%) showed the largest mean drop size, and lowest amount of free starch, which could be an effect of a higher degree of aggregation of the starch granules and, thereby, also the emulsion drops stabilized by them. The heat treated starch granules had a poor stabilizing ability and only the starch heated for the longest time (150 min at 120 degrees C) had a better emulsifying capacity than the un-modified native starch granules. The effect of salt concentration was rather limited. However, an increased concentration of salt slightly increased the mean drop size and the elastic modulus.

Method of making carbon-carbon composites

DOEpatents

Engle, Glen B.

1991-01-01

A process for making a carbon-carbon composite having a combination of high crystallinity, high strength, high modulus and high thermal and electrical conductivity. High-modulus/high-strength mesophase derived carbon fibers are woven into a suitable cloth. Layers of this easily graphitizable woven cloth are covered with petroleum or coal tar pitch and pressed at a temperature a few degrees above the softening point of the pitch to form a green laminated composite. The green composite is restrained in a suitable fixture and heated slowly to carbonize the pitch binder. The carbonized composite is then impregnated several times with pitch by covering the composite with hot pitch under pressure. The composites are given a heat treatment between each impregnation step to crack up the infiltrated carbon and allow additional pitch to enter the microstructure during the next impregnation cycle. The impregnated composites are then given a final heat treatment in the range 2500.degree. to 3000.degree. C. to fully graphitize the fibers and the matrix carbon. The composites are then infiltrated with pyrolytic carbon by chemical vapor deposition in the range 1000.degree. to 1300.degree. C. at a reduced pressure for approximately one hundred and fifty (150) hours.

Origin of chlorophyll fluorescence in plants at 55-75 degrees C.

PubMed

Ilík, Petr; Kouril, Roman; Kruk, Jerzy; Myśliwa-Kurdziel, Beata; Popelková, Hana; Strzałka, Kazimierz; Naus, Jan

2003-01-01

The origin of heat-induced chlorophyll fluorescence rise that appears at about 55-60 degrees C during linear heating of leaves, chloroplasts or thylakoids (especially with a reduced content of grana thylakoids) was studied. This fluorescence rise was earlier attributed to photosystem I (PSI) emission. Our data show that the fluorescence rise originates from chlorophyll a (Chl a) molecules released from chlorophyll-containing protein complexes denaturing at 55-60 degrees C. This conclusion results mainly from Chl a fluorescence lifetime measurements with barley leaves of different Chl a content and absorption and emission spectra measurements with barley leaves preheated to selected temperatures. These data, supported by measurements of liposomes with different Chl a/lipid ratios, suggest that the released Chl a is dissolved in lipids of thylakoid membranes and that with increasing Chl a content in the lipid phase, the released Chl a tends to form low-fluorescing aggregates. This is probably the reason for the suppressed fluorescence rise at 55-60 degrees C and the decreasing fluorescence course at 60-75 degrees C, which are observable during linear heating of plant material with a high Chl a/lipid ratio (e.g. green leaves, grana thylakoids, isolated PSII particles).

Disinfection/sterilization of extracted teeth for dental student use.

PubMed

Dominici, J T; Eleazer, P D; Clark, S J; Staat, R H; Scheetz, J P

2001-11-01

Extracted human teeth are used in many preclinical courses. While there has been no report of disease transmission with extracted teeth, sterilization of teeth used in the teaching laboratory should be a concern. The purpose of this study was to determine the effectiveness of different sterilization/disinfection methods of extracted human teeth using Bacillus stearothermophilus, a bacteria resistant to heat and frequently used to test sterilizers. In this study, 110 extracted molars with no carious lesions were collected and stored in buffered saline. An endodontic occlusal access preparation was cut into the pulp chamber of each tooth. Pulp tissue in the chamber was removed with a broach. Approximately 1 x 10(5) B. stearothermophilus endospores in culture medium were injected into the pulp chamber, sealed with Cavit G, and then placed in sterile saline for twelve hours. Ten teeth were placed into each of eleven groups. Seven groups were immersed for one week in one of the following solutions: a) sterile saline (control group), b) 5.25% NaOCl, c) 2.6% NaOCl, d) 1% NaOCl, e) 10% buffered formalin, f) 2% gluteraldehyde, g) 0.28% quaternary ammonium. Four additional groups were treated by h) 10% formalin for two days, i) 10% formalin for four days, j) autoclaving at 240 degrees F and 20 psi for twenty minutes, and k) autoclaving at 240 degrees F and twenty psi for forty minutes. Each tooth was then aseptically split and placed in an individual test tube with growth medium. Samples were examined for evidence of growth (turbidity) at forty-eight hours. Only autoclaving for forty minutes at 240 degrees F and 20 psi or soaking in 10 percent formalin for one week were 100 percent effective in preventing growth. A chi-square analysis of the data indicates these two methods were significantly better than all other methods (p<0.001).

The balance between stress resilience and vulnerability is regulated by corticotropin-releasing hormone during the critical postnatal period for sensory development.

PubMed

Cramer, Tomer; Kisliouk, Tatiana; Yeshurun, Shlomo; Meiri, Noam

2015-08-01

Determining whether a stressful event will lead to stress-resilience or vulnerability depends probably on an adjustable stress response set point, which is most likely effective during postnatal sensory development and involves the regulation of corticotrophin-releasing hormone (CRH) expression. During the critical period of thermal-control establishment in 3-day-old chicks, heat stress was found to render resilient or sensitized response, depending on the ambient temperature. These two different responses were correlated with the amount of activation of the hypothalamic-pituitary-adrenal (HPA) axis. The expression of CRH mRNA in the hypothalamic paraventricular nucleus was augmented during heat challenge a week after heat conditioning in chicks which were trained to be vulnerable to heat, while it declined in chicks that were trained to be resilient. To study the role of CRH in HPA-axis plasticity, CRH or Crh-antisense were intracranially injected into the third ventricle. CRH caused an elevation of both body temperature and plasma corticosterone level, while Crh-antisense caused an opposite response. Moreover, these effects had long term implications by reversing a week later, heat resilience into vulnerability and vice versa. Chicks that had been injected with CRH followed by exposure to mild heat stress, normally inducing resilience, demonstrated, a week later, an elevation in body temperature, and Crh mRNA level similar to heat vulnerability, while Crh-antisense injected chicks, which were exposed to harsh temperature, responded in heat resilience. These results demonstrate a potential role for CRH in determining the stress resilience/vulnerability balance. © 2014 Wiley Periodicals, Inc.

Thermal behavior of a pharmaceutical solid acetaminophen doped with p-aminophenol.

PubMed

Faroongsarng, D; Kadejinda, W; Sunthornpit, A

2000-07-30

Thermal behavior of a series of acetaminophen (APAP) doped with p-aminophenol (PANP) was studied by differential scanning calorimetry (DSC) to determine whether it exhibited a eutectic system. Within the temperature range of 120 to 200 degrees C, accurately weighed (1-2 mg) samples sealed in hermetic pans were calorimetrically scanned with a low scanning rate of 1 degrees C/min. The mixture formed a single eutectic with the composition ratio APAP/PANP of 0.6/0.4 at a temperature of 138 degrees C, where it liquefied. Melting began as early as at the eutectic point, which was below the melting temperature of APAP (169 degrees C). The melting point as well as heat of APAP fusion was depressed with the increase in doped PANP. It was postulated that there might be a deficit heat of APAP fusion in APAP doped with PANP, which was coincident with the heat consumed by early liquefaction. The deficit heat was used to correct fraction molten in the van't Hoff law of purity determination. It was found that the purity determination of APAP doped with PANP was comparable to the UV-spectroscopic method up to the maximum doped PANP level of 8 mol percent. It was concluded that DSC was able to approach early heat of liquefaction of APAP doped with PANP. The van't Hoff law may be applicable to the determination of APAP with the presence of PANP as a eutectic impurity.

Thermophysical Properties of Alloy 617 from 25°C to 1000°C

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

B. H. Rabin; R. N. Wright; W. D. Swank

2013-09-01

Key thermophysical properties needed for the successful design and use of Alloy 617 in steam generator and heat exchanger applications have been measured experimentally, and results are compared with literature values and results obtained from some other commercial Ni–Cr alloys and model materials. Specifically, the thermal diffusivity, thermal expansion coefficient, and specific heat capacity have been measured for Alloy 617 over a range of temperatures, allowing calculation of thermal conductivity up to 1000 degrees C. It has been found that the thermal conductivity of Alloy 617 exhibits significant deviation from monotonic behavior in the temperature range from 600 degrees Cmore » to 850 degrees C, the temperatures of interest for most heat transfer applications. The non-linear behavior appears to result primarily from short-range order/disorder phenomena known to occur in the Ni–Cr system. Similar deviation from monotonic behavior was observed in the solid solution Ni–Cr-W Alloy 230, and lesser deviations were observed in iron based Alloy 800H and an austenitic stainless steel. Measured thermophysical property data are provided for four different heats of Alloy 617, and it is shown that property variations between the four different heats are not significant. Measurements were also obtained from Alloy 617 that was aged for up to 2000 h at 750 degrees C, and it was found that this aging treatment does not significantly influence the thermophysical properties.« less

A rapid decrease in temperature induces latewood formation in artificially reactivated cambium of conifer stems

PubMed Central

Begum, Shahanara; Nakaba, Satoshi; Yamagishi, Yusuke; Yamane, Kenichi; Islam, Md. Azharul; Oribe, Yuichiro; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

2012-01-01

Background and Aims Latewood formation in conifers occurs during the later part of the growing season, when the cell division activity of the cambium declines. Changes in temperature might be important for wood formation in trees. Therefore, the effects of a rapid decrease in temperature on cellular morphology of tracheids were investigated in localized heating-induced cambial reactivation in Cryptomeria japonica trees and in Abies firma seedlings. Methods Electric heating tape and heating ribbon were wrapped on the stems of C. japonica trees and A. firma seedlings. Heating was discontinued when 11 or 12 and eight or nine radial files of differentiating and differentiated tracheids had been produced in C. japonica and A. firma stems, respectively. Tracheid diameter, cell wall thickness, percentage of cell wall area and percentage of lumen area were determined by image analysis of transverse sections and scanning electron microscopy. Key Results Localized heating induced earlier cambial reactivation and xylem differentiation in stems of C. japonica and A. firma as compared with non-heated stems. One week after cessation of heating, there were no obvious changes in the dimensions of the differentiating tracheids in the samples from adult C. japonica. In contrast, tracheids with a smaller diameter were observed in A. firma seedlings after 1 week of cessation of heating. Two or three weeks after cessation of heating, tracheids with reduced diameters and thickened cell walls were found. The results showed that the rapid decrease in temperature produced slender tracheids with obvious thickening of cell walls that resembled latewood cells. Conclusions The results suggest that a localized decrease in temperature of stems induces changes in the diameter and cell wall thickness of differentiating tracheids, indicating that cambium and its derivatives can respond directly to changes in temperature. PMID:22843340

Assessing potential climate change pressures across the conterminous United States: mapping plant hardiness zones, heat zones, growing degree days, and cumulative drought severity throughout this century

Treesearch

Stephen N. Matthews; Louis R. Iverson; Matthew P. Peters; Anantha M. Prasad

2018-01-01

The maps and tables presented here represent potential variability of projected climate change across the conterminous United States during three 30-year periods in this century and emphasizes the importance of evaluating multiple signals of change across large spatial domains. Maps of growing degree days, plant hardiness zones, heat zones, and cumulative drought...

Processes for preparing carbon fibers using gaseous sulfur trioxide

DOEpatents

Barton, Bryan E.; Lysenko, Zenon; Bernius, Mark T.; Hukkanen, Eric J.

2016-01-05

Disclosed herein are processes for preparing carbonized polymers, such as carbon fibers, comprising: sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 gas to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of said solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C.

The Correlation of Standard Entropy with Enthalpy Supplied from 0 to 298.15 K

ERIC Educational Resources Information Center

Lambert, Frank L.; Leff, Harvey S.

2009-01-01

As a substance is heated at constant pressure from near 0 K to 298 K, each incremental enthalpy increase, dH, alters entropy by dH/T, bringing it from approximately zero to its standard molar entropy S degrees. Using heat capacity data for 32 solids and CODATA results for another 45, we found a roughly linear relationship between S degrees and…

Design and Preliminary Thermal Performance of the Mars Science Laboratory Rover Heat Exchangers

NASA Technical Reports Server (NTRS)

Mastropietro, A. J.; Beatty, John; Kelly, Frank; Birur, Gajanana; Bhandari, Pradeep; Pauken, Michael; Illsley, Peter; Liu, Yuanming; Bame, David; Miller, Jennifer

2010-01-01

The challenging range of proposed landing sites for the Mars Science Laboratory Rover requires a rover thermal management system that is capable of keeping temperatures controlled across a wide variety of environmental conditions. On the Martian surface where temperatures can be as cold as -123 degrees Centigrade and as warm as 38 degrees Centigrade, the Rover relies upon a Mechanically Pumped Fluid Loop (MPFL) and external radiators to maintain the temperature of sensitive electronics and science instruments within a -40 degrees Centigrade to 50 degrees Centigrade range. The MPFL also manages significant waste heat generated from the Rover power source, known as the Multi Mission Radioisotope Thermoelectric Generator (MMRTG). The MMRTG produces 110 Watts of electrical power while generating waste heat equivalent to approximately 2000 Watts. Two similar Heat Exchanger (HX) assemblies were designed to both acquire the heat from the MMRTG and radiate waste heat from the onboard electronics to the surrounding Martian environment. Heat acquisition is accomplished on the interior surface of each HX while heat rejection is accomplished on the exterior surface of each HX. Since these two surfaces need to be at very different temperatures in order for the MPFL to perform efficiently, they need to be thermally isolated from one another. The HXs were therefore designed for high in-plane thermal conductivity and extremely low through-thickness thermal conductivity by using aerogel as an insulator inside composite honeycomb sandwich panels. A complex assembly of hand welded and uniquely bent aluminum tubes are bonded onto the HX panels and were specifically designed to be easily mated and demated to the rest of the Rover Heat Recovery and Rejection System (RHRS) in order to ease the integration effort. During the cruise phase to Mars, the HX assemblies serve the additional function of transferring heat from the Rover MPFL to the separate Cruise Stage MPFL so that heat generated deep inside the Rover can be dissipated via the Cruise Stage radiators. Significant fabrication challenges had to be overcome in order to make the HX design a reality. The cruise phase thermal performance of the Rover HXs was verified in the cruise phase system level thermal vacuum test that was performed at JPL in January of 2009. The Rover HXs were modeled in I-DEAS TMG and predictions are compared to actual data from the test.

Two chamber reaction furnace

DOEpatents

Blaugher, Richard D.

1998-05-05

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Vertical two chamber reaction furnace

DOEpatents

Blaugher, Richard D.

1999-03-16

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Enhancement of parathion toxicity to quail by heat and cold exposure

USGS Publications Warehouse

Rattner, B.A.; Becker, J.M.; Nakatsugawa, T.

1987-01-01

Effects of ambient temperature on the acute oral toxicity of parathion were investigated in Japanese quail (Coturnix japonica) maintained at thermoneutral temperature (26.degree. C) or exposed to elevated (37.degree. C) or reduced (4.degree. C) temperatures commonly encountered by free-ranging wild birds. Based upon estimates of the median lethal dosage, there was up to a two-fold enhancement of parathion toxicity in birds chronically exposed to heat or cold. Twenty-four hours after administration of a low dosage (4 mg/kg body wt, po), there was markedly greater cholinesterase inhibition in surviving heat-exposed quail compared with those reared at 26.degree. C (e.g., brain acetylcholinesterase depression of 42% versus 12%). There were no differences in hepatic activities of parathion oxidase, paraoxonase, or paraoxon deethylase which could account for greater toxicity to chronically heat-exposed birds. In contrast, 4 mg parathion/kg wt elicited less plasma cholinesterase inhibition in cold-exposed quail compared to thermoneutral controls (e.g., < 10% versus 48% depression after 24 hr). Increased liver weight and a doubling of paraoxonase activity may have been associated with greater tolerance to sublethal doses of parathion in chronically cold-exposed quail. These findings, together with limited field observations, indicate that the hazard associated with anticholinesterase exposure of wild birds is substantially influenced by environmental temperature.

Experimental and theoretical studies of light-to-heat conversion and collective heating effects in metal nanoparticle solutions.

PubMed

Richardson, Hugh H; Carlson, Michael T; Tandler, Peter J; Hernandez, Pedro; Govorov, Alexander O

2009-03-01

We perform a set of experiments on photoheating in a water droplet containing gold nanoparticles (NPs). Using photocalorimetric methods, we determine efficiency of light-to-heat conversion (eta) which turns out to be remarkably close to 1, (0.97 < eta < 1.03). Detailed studies reveal a complex character of heat transfer in an optically stimulated droplet. The main mechanism of equilibration is due to convectional flow. Theoretical modeling is performed to describe thermal effects at both nano- and millimeter scales. Theory shows that the collective photoheating is the main mechanism. For a large concentration of NPs and small laser intensity, an averaged temperature increase (at the millimeter scale) is significant (approximately 7 degrees C), whereas on the nanometer scale the temperature increase at the surface of a single NP is small (approximately 0.02 degrees C). In the opposite regime, that is, a small NP concentration and intense laser irradiation, we find an opposite picture: a temperature increase at the millimeter scale is small (0.1 degrees C) but a local, nanoscale temperature has strong local spikes at the surfaces of NPs (approximately 3 degrees C). These studies are crucial for the understanding of photothermal effects in NPs and for their potential and current applications in nano- and biotechnologies.

Hyperthermia combined with ethanol administration induces c-fos expression in the central amygdaloid nucleus of the mouse brain. A possible mechanism of heatstroke under the influence of ethanol intake.

PubMed

Kibayashi, Kazuhiko; Nakao, Ken-ichiro; Shojo, Hideki

2009-09-01

Heatstroke is defined as a core body temperature that rises above 40.6 degrees C and is accompanied by mental status abnormalities such as delirium, convulsions, or coma resulting from exposure to environmental heat. There is fairly wide agreement that ethanol intake is a predisposing factor in heatstroke. This study was performed to identify the brain changes induced by heatstroke, using a mouse hyperthermia model with and without preceding ethanol administration. Exposure to heat of 42 degrees C until the core temperature reached to 43 degrees C followed by exposure to 37 degrees C for 15 min decreased the levels of partial pressures of O(2) in blood. Preceding ethanol administration and heat exposure induced hypotension, severe metabolic acidosis and respiratory failure, and, accordingly, produced heatstroke. Immunohistochemistry of the brains showed that preceding ethanol administration increased the number of c-fos-immunoreactive neurons, as a marker of neuronal activation, in the central amygdaloid nucleus, which is involved in thermoregulation. These results indicate that combined effects of ethanol and heat exposure induce heatstroke that is associated with activation of the central amygdaloid nucleus, implicating the pathophysiology and mechanisms of heatstroke under the influence of ethanol intake.

In vitro comparison of autoclave polymerization on the transverse strength of denture base resins.

PubMed

Durkan, Rukiye; Ozel, Mehmet Birol; Bağiş, Bora; Usanmaz, Ali

2008-07-01

The aim of this study was to determine the effect of autoclave polymerization on the transverse strength of denture base polymers. To this end, 30 rectangular test specimens were fabricated of two heat-polymerized denture base polymers. The test groups were: (I) control, i.e., conventional water bath to polymerize resins by heat at 100 degrees C for 30 minutes; (II) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 10 minutes; and (III) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 20 minutes. The specimens were tested with three-point bending test at a crosshead speed of 5 mm/min. It was revealed that the transverse strength of specimens increased with statistical significance when the autoclave was used for polymerization.

Influence of storage on volatile profiles in roasted almonds (Prunus dulcis).

PubMed

Lee, Jihyun; Xiao, Lu; Zhang, Gong; Ebeler, Susan E; Mitchell, Alyson E

2014-11-19

Hexanal, peroxide value, and lipid hydroperoxides are common indicators of lipid oxidation in food products. However, these markers are not always reliable as levels are dynamic and often can be detected only after significant oxidation has occurred. Changes in the volatile composition of light- and dark-roast almonds were evaluated during storage over 24 weeks at 25 or 35 °C using headspace solid phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). Several volatile changes were identified in association with early oxidation events in roasted almonds. Hexenal decreased significantly during the first 6 weeks of storage and did not increase above initial levels until 20-24 weeks of storage depending upon the degree of roast. In contrast, levels of 1-heptanol and 1-octanol increased at 16-20 weeks, depending upon the degree of roast, and no initial losses were observed. Seventeen new compounds, absent in raw and freshly roasted almonds but detectable after 6 weeks of storage, were identified. Of these, 2-octanone, 2-nonanone, 3-octen-2-one, 2-decanone, (E)-2-decenal, 2,4-nonadienal, pentyl oxirane, and especially acetic acid increased significantly (that is, >10 ng/g). The degree of roasting did not correlate with the levels of these compounds. Significant decreases in roasting-related aroma volatiles such as 2-methylbutanal, 3-methylbutanal, furfural, 2-phenylacetaldehyde, 2,3-butanedione, 2-methylpyrazine, and 1-methylthio-2-propanol were observed by 4 weeks of storage independent of the degree of roast or storage conditions.

Four Day School Week for Small Rural Schools. Small Schools Fact Sheet.

ERIC Educational Resources Information Center

Culbertson, Jeanne

The four-day school week is a Monday-Thursday or Tuesday-Friday alternative to the traditional four-day week, which can be implemented with many variables and differing objectives. The four-day week saves heating, transportation, maintenance, electricity and some instructional costs, while providing better educational opportunities and use of…

Method for creating high carbon content products from biomass oil

DOEpatents

Parker, Reginald; Seames, Wayne

2012-12-18

In a method for producing high carbon content products from biomass, a biomass oil is added to a cracking reactor vessel. The biomass oil is heated to a temperature ranging from about 100.degree. C. to about 800.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to crack the biomass oil. Tar is separated from the cracked biomass oil. The tar is heated to a temperature ranging from about 200.degree. C. to about 1500.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to reduce the tar to a high carbon content product containing at least about 50% carbon by weight.

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

NASA Astrophysics Data System (ADS)

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

2002-06-01

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

Cytotoxicity of denture base resins: effect of water bath and microwave postpolymerization heat treatments.

PubMed

Jorge, Janaina Habib; Giampaolo, Eunice Teresinha; Vergani, Carlos Eduardo; Machado, Ana Lúcia; Pavarina, Ana Cláudia; Carlos, Iracilda Zeppone

2004-01-01

This study compared the effect of two postpolymerization heat treatments on the cytotoxicity of three denture base resins on L929 cells using 3H-thymidine incorporation and MTT assays. Sample disks of Lucitone 550, QC 20, and Acron MC resins were fabricated under aseptic conditions and stored in distilled water at 37 degrees C for 48 hours. Specimens were then divided into three groups: (1) heat treated in microwave oven for 3 minutes at 500 W; (2) heat treated in water bath at 55 degrees C for 60 minutes; and (3) no heat treatment. Eluates were prepared by placing three disks into a sterile glass vial with 9 mL of Eagle's medium and incubating at 37 degrees C for 24 hours. The cytotoxic effect from the eluates was evaluated using the 3H-thymidine incorporation and MTT assays, which reflect DNA synthesis levels and cell metabolism, respectively. The components leached from the resins were cytotoxic to L929 cells when 3H-thymidine incorporation assay was employed. In contrast, eluates from all resins revealed noncytotoxic effects as measured by MTT assay. For both MTT assay and 3H-thymidine incorporation, the heat treatments did not decrease the cytotoxicity of the materials tested. Resins were graded by 3H-thymidine incorporation assay as slightly cytotoxic and by MTT assay as noncytotoxic. Cytotoxicity of the denture base materials was not influenced by microwave or water bath heat treatment.

Martian Electron Temperatures in the Sub Solar Region.

NASA Astrophysics Data System (ADS)

Fowler, C. M.; Peterson, W. K.; Andersson, L.; Thiemann, E.; Mayyasi, M.; Yelle, R. V.; Benna, M.; Espley, J. R.

2017-12-01

Observations from Viking, and MAVEN have shown that the observed ionospheric electron temperatures are systematically higher than those predicted by many models. Because electron temperature is a balance between heating, cooling, and heat transport, we systematically compare the magnitude of electron heating from photoelectrons, electron cooling and heat transport, as a function of altitude within 30 degrees of the sub solar point. MAVEN observations of electron temperature and density, EUV irradiance, neutral and ion composition are used to evaluate terms in the heat equation following the framework of Matta et al. (Icarus, 2014, doi:10.1016/j.icarus.2013.09.006). Our analysis is restricted to inbound orbits where the magnetic field is within 30 degrees of horizontal. MAVEN sampled the sub solar region in May 2015 and again in May 2017, in near northern spring equinoctial conditions. Solar activity was higher and the spacecraft sampled altitudes down to 120 km in 2015, compared to 160 km in 2017. We find that between 160 and 200 km the Maven electron temperatures are in thermal equilibrium, in the sub solar region, on field lines inclined less than 30 degrees to the horizontal. Above 200km the data suggest that heating from other sources, such as wave heating are significant. Below 160 km some of the discrepancy comes from measurement limitations. This is because the MAVEN instrument cannot resolve the lowest electron temperatures, and because some cooling rates scale as the difference between the electron and neutral temperatures.

Life-threatening heat stroke presenting with ST elevations: a report of consecutive cases during the heat wave in Austria in July 2013.

PubMed

Lassnig, Elisabeth; Dinkhauser, Patrick; Maurer, Edwin; Eber, Bernd

2014-08-01

Heat stroke is a life-threatening condition due to an acute thermoregulatory failure during exposure to high environmental temperatures. We report a series of four cases (three exertional, one classic heat stroke) during the heat wave of July 2013 in Austria. All of them presented with a core temperature > 41 °C, central nervous dysfunction, acute respiratory and renal failure, disseminated intravascular coagulation, rhabdomyolysis, and severe electrocardiographic changes, two cases even mimicking ST-elevation myocardial infarction. The patients were cooled to normal temperature with the "Arctic sun" external cooling system within hours. Electrocardiographic changes resolved quickly. All patients primarily recovered from multiple organ dysfunction and could be discharged from intensive care unit. Unfortunately, the two elder patients died 1 week and 5 weeks later because of late complications.

A new osteonecrosis animal model of the femoral head induced by microwave heating and repaired with tissue engineered bone

PubMed Central

Han, Rui; Geng, Chengkui; Wang, Yongnian; Wei, Lei

2008-01-01

The objective of this research was to induce a new animal model of osteonecrosis of the femoral head (ONFH) by microwave heating and then repair with tissue engineered bone. The bilateral femoral heads of 84 rabbits were heated by microwave at various temperatures. Tissue engineered bone was used to repair the osteonecrosis of femoral heads induced by microwave heating. The roentgenographic and histological examinations were used to evaluate the results. The femoral heads heated at 55°C for ten minutes showed low density and cystic changes in X-ray photographs, osteonecrosis and repair occurred simultaneously in histology at four and eight weeks, and 69% femoral heads collapsed at 12 weeks. The ability of tissue engineered bone to repair the osteonecrosis was close to that of cancellous bone autograft. The new animal model of ONFH could be induced by microwave heating, and the tissue engineering technique will provide an effective treatment. PMID:18956184

The influence of metabolic heat production on body temperature of a small lizard, Anolis carolinensis.

PubMed

Brown, Richard P; Au, Timothy

2009-06-01

Little is known about the impact of increased metabolism on body temperatures of small ectotherms. We found that postprandial metabolic rates of 5 g Anolis carolinensis lizards were elevated by factorial increases of 2.3+/-1.0 (mean+/-S.E.) at 26 degrees C and 3.8+/-2.1 at 30 degrees C over their fasting rates. Cloacal body temperatures exceeded environmental temperatures by a small amount in fasted individuals (26 degrees C: 0.3+/-0.02 degrees C, 30 degrees C: 0.3+/-0.02 degrees C), and by a significantly larger amount in fed individuals (26 degrees C: 1.0+/-0.06 degrees C, 30 degrees C: 0.8+/-0.08 degrees C). We conclude that an increased metabolic rate due to specific dynamic action leads to a small but significant elevation of body temperature in this species. Comparisons with thermal increments reported for a large (750 g) varanid lizard suggest that body size has only a minor influence on body-air temperature differentials of ectotherms. This is consistent with theoretical predictions. Finally, endogenous heat production could help elevate body temperatures in the wild and therefore play a minor role in thermoregulation.

Thermal-hydraulic behavior of a mixed chevron single-pass plate-and-frame heat exchanger

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

Manglik, R.M.; Muley, A.

1995-12-31

Effective heat exchange is very critical for improving the process efficiency and operating economy of chemical and process plants. Here, experimental friction factor and heat transfer data for single-phase water flows in a plate-and-frame heat exchanger are presented. A mixed chevron plate arrangement with {beta} = 30{degree}/60{degree} in a single-pass U-type, counterflow configuration is employed. The friction factor and heat transfer data are for isothermal flow and cooling conditions, respectively, and the flow rates correspond to transition and turbulent flow regimes (300 < Re < 6,000 and 2.4 < Pr < 4.5). Based on these data, Nusselt number and frictionmore » factor correlations for fully developed turbulent flows (Re {ge} 1,000) are presented. The results highlight the effects of {beta} on the thermal-hydraulic performance, transition to turbulent flows, and the relative impact of using symmetric or mixed chevron plate arrangements.« less

Method of manufacturing a niobium-aluminum-germanium superconductive material

DOEpatents

Wang, John L.; Pickus, Milton R.; Douglas, Kent E.

1980-01-01

A method for manufacturing flexible Nb.sub.3 (Al,Ge) multifilamentary superconductive material in which a sintered porous niobium compact is infiltrated with an aluminum-germanium alloy and thereafter deformed and heat treated in a series of steps at different successively higher temperatures preferably below 1000.degree. C. to produce filaments composed of Nb.sub.3 (Al,G3) within the compact. By avoiding temperatures in excess of 1000.degree. C. during the heat treatment, cladding material such as copper can be applied to facilitate a deformation step preceding the heat treatment and can remain in place through the heat treatment to also serve as a temperature stabilizer for supeconductive material produced. Further, these lower heat treatment temperatures favor formation of filaments with reduced grain size and, hence with more grain boundaries which in turn increase the current-carrying capacity of the superconductive material.

Tomato growth as affected by root-zone temperature and the addition of gibberellic acid and kinetin to nutrient solutions

NASA Technical Reports Server (NTRS)

Bugbee, B.; White, J. W.; Salisbury, F. B. (Principal Investigator)

1984-01-01

The effect of root-zone temperature on young tomato plants (Lycopersicon esculentum Mill. cv. Heinz 1350) was evaluated in controlled environments using a recirculating solution culture system. Growth rates were measured at root-zone temperatures of 15 degrees, 20 degrees, 25 degrees, and 30 degrees C in a near optimum foliar environment. Optimum growth occurred at 25 degrees to 30 degrees during the first 4 weeks of growth and 20 degrees to 25 degrees during the 5th and 6th weeks. Growth was severely restricted at 15 degrees. Four concentrations of gibberellic acid (GA3) and kinetin were added to the nutrient solution in a separate trial; root-zone temperature was maintained at 15 degrees and 25 degrees. Addition of 15 micromoles GA3 to solutions increased specific leaf area, total leaf area, and dry weight production of plants in both temperature treatments. GA3-induced growth stimulation was greater at 15 degrees than at 25 degrees. GA3 may promote growth by increasing leaf area, enhancing photosynthesis per unit leaf area, or both. Kinetic was not useful in promoting growth at either temperature.

Thermal transfer in extracted incisors during thermal pulp sensitivity testing.

PubMed

Linsuwanont, P; Palamara, J E; Messer, H H

2008-03-01

To measure the temperature distribution within tooth structure during and after application of thermal stimuli used during pulp sensitivity testing. Extracted intact human maxillary anterior teeth were investigated for temperature changes at the labial enamel, the dentino-enamel junction (DEJ) and pulpal surface during and after a 5-s application of six different thermal stimuli: hot water (80 degrees C), heated gutta-percha (140 degrees C), carbon dioxide dry ice (-72 degrees C), refrigerant spray (-50 degrees C), ice stick (0 degrees C) and cold water (2 degrees C). J-type thermocouples and heat conduction paste were used to detect temperature changes, together with a data acquisition system (Labview). Data were analysed using analysis of variance, with a confidence level of P < 0.05. Temperature change was detected more quickly at the DEJ and pulpal surface with the application of hot water, heated gutta-percha and refrigerant spray than with carbon dioxide dry ice and ice (P < 0.05). Cold water and refrigerant spray were in the same range in terms of time to detect temperature change at both the DEJ and pulpal surface. Thermal stimuli with greater temperature difference from tooth temperature created a greater thermal gradient initially, followed by a greater temperature change at the DEJ and the pulpal surface. In this regard, ice and cold water were weaker stimuli than others (P < 0.05). Thermal stimuli used in pulp testing are highly variable in terms of temperature of the stimulus, rate of thermal transfer to the tooth and extent of temperature change within tooth structure. Overall, dry ice and refrigerant spray provide the most consistent stimuli, whereas heated gutta-percha and hot water were highly variable. Ice was a weak stimulus.

Daily Air Temperature and Electricity Load in Spain.

NASA Astrophysics Data System (ADS)

Valor, Enric; Meneu, Vicente; Caselles, Vicente

2001-08-01

Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a `comfort interval' of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in the warm season. Two different temperature-derived variables that allow a better characterization of the observed relationship have been used: the heating and cooling degree-days. The regression of electricity data on them defines the heating and cooling demand functions, which show correlation coefficients of 0.79 and 0.87, and predicts electricity load with standard errors of estimate of ±4% and ±2%, respectively. The maximum elasticity of electricity demand is observed at 7 cooling degree-days and 9 heating degree-days, and the saturation points are reached at 11 cooling degree-days and 13 heating degree-days, respectively. These results are helpful in modeling electricity load behavior for predictive purposes.

Nocturnal pituitary hormone and renin profiles during chronic heat exposure.

PubMed

Saini, J; Brandenberger, G; Libert, J P; Follenius, M

1993-07-01

To establish the principal endocrine systems involved in the initial adaptation to chronic passive heat exposure, responses of the hydromineral and pituitary systems were compared. Nocturnal plasma profiles of growth hormone, prolactin, thyrotropin, and plasma renin activity were determined during a period of prolonged heat exposure designed to simulate a hot climate. Two groups of six male subjects (G1 and G2) were kept for 11 days in a climatically controlled apartment. The G1 group was exposed to 20 degrees C throughout the study, and the G2 group was exposed to 20 degrees C for 5 days and to 35 degrees C for the following 6 days. Blood was collected continuously during the 1st and 10th nights from 2300 to 0700 h and was sampled in 10-min aliquots for hormone analysis. Heat exposure increased the nocturnal mean core temperature (P < 0.02) and stimulated plasma renin activity (P < 0.01) but had little effect on the pituitary hormones except for a small increase in prolactin (P < 0.05). For the G1 group there was no change in hormone profiles. These results demonstrate that the principal initial endocrine system involved in acclimatization to passive heat exposure is the renin-angiotensin system, reflecting counteractive measures against salt and water losses. In contrast, 5 days of continuous heat exposure does not provoke metabolic changes, indicated by the small effect on pituitary hormone profiles.

Quantitative analysis of tridymite and cristobalite crystallized in rice husk ash by heating.

PubMed

Shinohara, Yasushi; Kohyama, Norihiko

2004-04-01

The quantities of two forms of crystalline silica, tridymite and cristobalite, in heated rice husk ash (RHA) samples were determined by X-ray diffraction (XRD) and chemical methods. Two RHA samples, containing 93% SiO2 and 2-3% K2O, were prepared from charcoaled rice husk products and heated to above 900 degrees C. The crystalline silica made up over 60-80% of the total silica in the heated RHA samples based on the XRD analysis. The crystalline phases in the two samples were somewhat different: The sample heated in the temperature range of 900 to 1,200 degrees C contained 52-62% cristobalite and 10-17% tridymite, but the other sample heated at a comparable temperature, above 1,100 degrees C, contained 46-66% tridymite and 37-16% cristobalite. Based on a correlation of lower tridymite crystallization temperature with higher potassium content, it was concluded that higher potassium levels were responsible for this difference. The pyrophosphoric acid analysis did not give exact results in the evaluation of total crystalline silica content in these RHA samples. As the combustion of rice husk was considered to cover the demands for energy and silica resource in Asian countries, cristobalite and tridymite crystallized in RHA by burning of rice husk should be assessed precisely by XRD analysis and the airborne dust in relevant workplace be controlled.

Biological responses in rats exposed to mainstream smoke from a heated cigarette compared to a conventional reference cigarette.

PubMed

Fujimoto, Hitoshi; Tsuji, Hiroyuki; Okubo, Chigusa; Fukuda, Ichiro; Nishino, Tomoki; Lee, K Monica; Renne, Roger; Yoshimura, Hiroyuki

2015-03-01

The heated cigarette (HC) generates mainstream smoke by vaporizing the components of the tobacco rod using a carbon heat source at the cigarette tip. Mainstream smoke of HC contains markedly less chemical constituents compared to combusted cigarettes. Mainstream smoke from HC was generated under Health Canada Intense regimen and its biological effects were compared to those of Reference (3R4F) cigarettes, using nose-only 5-week and 13-week inhalation studies. In the 13-week study, SD rats were necropsied following exposure to mainstream smoke from each cigarette at 200, 600 or 1000 µg wet total particulate matter/L for 1 h/day, 7 days/week or following a 13-week recovery period. Histopathological changes in the respiratory tract were significantly lesser in HC groups; e.g. respiratory epithelial hyperplasia in the nasal cavity and accumulation of pigmented macrophages in alveoli. After a 13-week recovery, the lesions were completely or partially regressed, except for accumulation of pigmented macrophages in alveoli, in both HC and 3R4F groups. In the 5-week study, SD rats were necropsied following exposure to mainstream smoke of either cigarette at 600 or 1000 µg/L for 1 h, two times/day (with 30 min interval), 7 days/week or following a 4-week recovery period. Bronchoalveolar lavage fluid (BALF) analysis of neutrophil percentages and enzyme levels like γ-GT, ALP and LDH indicated that pulmonary inflammation was significantly less in HC groups compared to 3R4F groups. In conclusion, HC demonstrated significantly lower biological effects compared to 3R4F, based on the BALF parameters and histopathology.

Heat transfer in turbulent magneto-fluid-mechanic pipe flow

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

Andelman, M.P.

1975-12-01

The ability to predict heat transfer in Magneto-Fluid-Mechanic flow is of importance in light of the development of MHD generators and the proposed development of thermonuclear reactors. In both cases heat transfer from (or to) a conducting fluid in the presence of a magnetic field plays an important part in the overall economics of the system. A semi-empirical analytical method is given for obtaining heat transfer coefficients in turbulent liquid metal pipe flow in the presence of a magnetic field aligned to the flow. The analysis was based on the Lykoudis turbulent transport model with the influence of a longitudinalmore » magnetic field included. The results are shown to be in agreement with available experimental values. Experimental velocity profiles in mercury for pipe flow in a transverse magnetic field were made at a Reynolds number of 315,000; for Hartmann numbers of 0, 92, 184, 369, and 1198; and at orientations of 0 degrees, 45 degrees, and 90 degrees from the magnetic field. These results provide a basis for the determination of the effect of a transverse magnetic field on turbulent diffusivities.« less

Effect of total solids content and temperature on the rheological behaviour of reconstituted whole milk concentrates.

PubMed

Trinh, Binh; Trinh, Khanh Tuoc; Haisman, Derek

2007-02-01

This work investigated the combined effect of solids content, heating and storage temperatures on the rheological behaviour of reconstituted whole milk concentrates. The powder was reconstituted at 35 degrees C in a custom built recombination rig to various total solids content (TS) from 10-48% TS. The concentrates were then heated to 45-85 degrees C and stored at the heating temperature. The rheological behaviour shifter from Newtonian behaviour (below 30% TS) to power law (below 40% TS), with the yield stress observed from 40% TS upwards and time-dependent behaviour was noticed above 44% TS. Higher heating temperatures tend to promote non-Newtonian behaviour at lower solids content. The viscosity-solid content curve showed an exponential relationship, while the viscosity-temperature curve exhibited a minimum at 65-75 degrees C above 46% TS. During age thickening, the yield stress and the consistency coefficient increased, while the flow behaviour index decreased with storage time. This indicated that the milk concentrates deviated away from Newtonian behaviour during age thickening.

Influence of nonequilibrium radiation and shape change on aerothermal environment of Jovian entry body

NASA Technical Reports Server (NTRS)

Tiwari, S. N.; Subramanian, S. V.

1980-01-01

Radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The nonequalibrium results, obtained with and without ablation injection in the shock layer, are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced significantly under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions. A 45 degree sphere cone, a 35 degree hyperboloid, and a 45 degree ellipsoid were used to study probe shape change. Results indicate that the shock layer flow field and heat transfer to the body are influenced significantly by the probe shape change. The effect of shape change on radiative heating of the afterbodies is found to be considerably larger for the sphere cone and ellipsoid than for the hyperboloid.

Resistive-heating or forced-air warming for the prevention of redistribution hypothermia.

PubMed

De Witte, Jan L; Demeyer, Caroline; Vandemaele, Els

2010-03-01

We evaluated the efficacy of resistive-heating or forced-air warming versus no prewarming, applied before induction of anesthesia for prevention of hypothermia. Twenty-seven patients scheduled for laparoscopic colorectal surgery were randomized into 1 of 3 groups: no prewarming; 30 minutes of prewarming with a carbon fiber total body cover at 42 degrees C; or 30 minutes of preoperative forced-air warming at 42 degrees C. The forced-air warming cover excluded the shoulders, ankles, and feet. The prewarming period was exactly 30 minutes. At the 31st minute, a total IV anesthesia technique was initiated, and all patients were actively warmed with a lithotomy blanket. Tympanic and distal esophageal temperatures were measured. Categorical data were analyzed using chi(2) test, and continuous data were analyzed with analysis of variance. P <0.05 was considered statistically significant. The mean esophageal temperatures differed significantly between the control and the carbon fiber group from 40 to 90 minutes of anesthesia. After 50 minutes of anesthesia, the mean esophageal temperatures in the control, carbon fiber, and forced-air groups were 35.9 degrees C +/- 0.3 degrees C, 36.5 degrees C +/- 0.4 degrees C, and 36.2 degrees C +/- 0.3 degrees C, respectively. No statistically significant difference was found between the forced-air and control groups. After 30 minutes of prewarming with resistive heating, patients had an esophageal temperature that was significantly higher than the control group. Prewarming should be considered part of the anesthetic management when patients are at risk for postoperative hypothermia.

Semiconductor junction formation by directed heat

DOEpatents

Campbell, Robert B.

1988-03-24

The process of the invention includes applying precursors 6 with N- and P-type dopants therein to a silicon web 2, with the web 2 then being baked in an oven 10 to drive off excessive solvents, and the web 2 is then heated using a pulsed high intensity light in a mechanism 12 at 1100.degree.-1150.degree. C. for about 10 seconds to simultaneously form semiconductor junctions in both faces of the web.

Process for removing heavy metal compounds from heavy crude oil

DOEpatents

Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

1991-01-01

A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

Carbon Film Electrodes For Super Capacitor Applications

DOEpatents

Tan, Ming X.

1999-07-20

A method for treating an organic polymer material, preferably a vinylidene chloride/vinyl chloride copolymer (Saran) to produce a flat sheet of carbon film material having a high surface area (.apprxeq.1000 m.sup.2 /g) suitable as an electrode material for super capacitor applications. The method comprises heating a vinylidene chloride/vinyl chloride copolymer film disposed between two spaced apart graphite or ceramic plates to a first temperature of about 160.degree. C. for about 14 hours to form a stabilized vinylidene chloride/vinyl chloride polymer film, thereafter heating the stabilized film to a second temperature of about 750.degree. C. in an inert atmosphere for about one hour to form a carbon film; and finally activating the carbon film to increase the surface area by heating the carbon film in an oxidizing atmosphere to a temperature of at least 750-850.degree. C. for between 1-6 hours.

Method for making carbon films

DOEpatents

Tan, Ming X.

1999-01-01

A method for treating an organic polymer material, preferably a vinylidene chloride/vinyl chloride copolymer (Saran) to produce a flat sheet of carbon film material having a high surface area (.apprxeq.1000 m.sup.2 /g) suitable as an electrode material for super capacitor applications. The method comprises heating a vinylidene chloride/vinyl chloride copolymer film disposed between two spaced apart graphite or ceramic plates to a first temperature of about 160.degree. C. for about 14 hours to form a stabilized vinylidene chloride/vinyl chloride polymer film, thereafter heating the stabilized film to a second temperature of about 750.degree. C. in an inert atmosphere for about one hour to form a carbon film; and finally activating the carbon film to increase the surface area by heating the carbon film in an oxidizing atmosphere to a temperature of at least 750-850.degree. C. for between 1-6 hours.

Short- and long-term clinical outcomes following a standardized protocol of orthopedic manual physical therapy and exercise in individuals with osteoarthritis of the hip: a case series

PubMed Central

Hando, Ben R; Gill, Norman W; Walker, Michael J; Garber, Mathew

2012-01-01

Objectives: Describe short- and long-term outcomes observed in individuals with hip osteoarthritis (OA) treated with a pre-selected, standardized set of best-evidence manual therapy and therapeutic exercise interventions. Methods: Fifteen consecutive subjects (9 males, 6 females; mean age: 52±7.5 years) with unilateral hip OA received an identical protocol of manual therapy and therapeutic exercise interventions. Subjects attended 10 treatment sessions over an 8-week period for manual therapy interventions and performed the therapeutic exercise as a home program. Results: Baseline to 8-week follow-up outcomes were as follows: Harris Hip Scale (HHS) scores improved from 60.3(±10.4) to 80.7(±10.5), Numerical Pain Rating Scale (NPRS) scores improved from 4.3(±1.9) to 2.0(±1.9), hip flexion range of motion (ROM) improved from 99 degrees (±10.6) to 127 degrees (±6.3) and hip internal rotation ROM improved from 19 degrees (±9.1) to 31 degrees (±11.5). Improvements in HHS, NPRS, and hip ROM measures reached statistical significance (P<0.05) at 8-weeks and remained significant at the 29-week follow-up. Mean changes in NPRS and HHS scores exceeded the minimal clinically important difference (MCID) at 8-weeks and for the HHS scores alone at 29 weeks. The 8 and 29 week mean Global Rating of Change scores were 5.1(±1.4) and 2.1(±4.2), respectively. Improved outcomes observed following a pre-selected, standardized treatment protocol were similar to those observed in previous studies involving impairment-based manual therapy and therapeutic exercise for hip OA. Future studies might directly compare the two approaches. Discussion: PMID:24179327

Short- and long-term clinical outcomes following a standardized protocol of orthopedic manual physical therapy and exercise in individuals with osteoarthritis of the hip: a case series.

PubMed

Hando, Ben R; Gill, Norman W; Walker, Michael J; Garber, Mathew

2012-11-01

Describe short- and long-term outcomes observed in individuals with hip osteoarthritis (OA) treated with a pre-selected, standardized set of best-evidence manual therapy and therapeutic exercise interventions. Fifteen consecutive subjects (9 males, 6 females; mean age: 52±7.5 years) with unilateral hip OA received an identical protocol of manual therapy and therapeutic exercise interventions. Subjects attended 10 treatment sessions over an 8-week period for manual therapy interventions and performed the therapeutic exercise as a home program. Baseline to 8-week follow-up outcomes were as follows: Harris Hip Scale (HHS) scores improved from 60.3(±10.4) to 80.7(±10.5), Numerical Pain Rating Scale (NPRS) scores improved from 4.3(±1.9) to 2.0(±1.9), hip flexion range of motion (ROM) improved from 99 degrees (±10.6) to 127 degrees (±6.3) and hip internal rotation ROM improved from 19 degrees (±9.1) to 31 degrees (±11.5). Improvements in HHS, NPRS, and hip ROM measures reached statistical significance (P<0.05) at 8-weeks and remained significant at the 29-week follow-up. Mean changes in NPRS and HHS scores exceeded the minimal clinically important difference (MCID) at 8-weeks and for the HHS scores alone at 29 weeks. The 8 and 29 week mean Global Rating of Change scores were 5.1(±1.4) and 2.1(±4.2), respectively. Improved outcomes observed following a pre-selected, standardized treatment protocol were similar to those observed in previous studies involving impairment-based manual therapy and therapeutic exercise for hip OA. Future studies might directly compare the two approaches.

Diclofenac salts. III. Alkaline and earth alkaline salts.

PubMed

Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa

2005-11-01

Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.

Poly I:C-induced fever elevates threshold for shivering but reduces thermosensitivity in rabbits.

PubMed

Tøien, Ø; Mercer, J B

1995-05-01

Shivering threshold and thermosensitivity were determined in six conscious rabbits at ambient temperature (Ta) 20 and 10 degrees C before and at six different times after saline injection (0.15 ml iv) and polyriboinosinic-polyribocytidylic acid (poly I:C)-induced fever (5 micrograms/kg iv). Thermosensitivity was calculated by regression of metabolic heat production (M) and hypothalamic temperature (Thypo) during short periods (5-10 min) of square-wave cooling. Heat was extracted with a chronically implanted intravascular heat exchanger. Shivering threshold was calculated as the Thypo at which the thermosensitivity line crossed resting M as measured in afebrile animals at Ta 20 degrees C. There were negligible changes in shivering threshold and thermosensitivity in saline-injected rabbits. In the febrile animals, shivering threshold generally followed the shape of the biphasic fever response. At Ta 20 degrees C, shivering threshold was higher than regulated Thypo during the initial rising phase of fever and was lower during recovery. At Ta 10 degrees C the shivering thresholds were always higher than regulated Thypo except during recovery. Thermosensitivity was reduced by 30-41% during fever.

Computation of Turbulent Heat Transfer on the Walls of a 180 Degree Turn Channel With a Low Reynolds Number Reynolds Stress Model

NASA Technical Reports Server (NTRS)

Ameri, A. A.; Rigby, D. L.; Steinthorsson, E.; Gaugler, Raymond (Technical Monitor)

2002-01-01

The Low Reynolds number version of the Stress-omega model and the two equation k-omega model of Wilcox were used for the calculation of turbulent heat transfer in a 180 degree turn simulating an internal coolant passage. The Stress-omega model was chosen for its robustness. The turbulent thermal fluxes were calculated by modifying and using the Generalized Gradient Diffusion Hypothesis. The results showed that using this Reynolds Stress model allowed better prediction of heat transfer compared to the k-omega two equation model. This improvement however required a finer grid and commensurately more CPU time.

NUCLEAR POWER PLANT WASTE HEAT HORTICULTURE

EPA Science Inventory

The report gives results of a study of the feasibility of using low grade (70 degrees F) waste heat from the condenser cooling water of the Vermont Yaknee nuclear plant for commercial food enhancement. The study addressed the possible impact of laws on the use of waste heat from ...

Method of producing a colloidal fuel from coal and a heavy petroleum fraction

DOEpatents

Longanbach, James R.

1983-08-09

A method is provided for combining coal as a colloidal suspension within a heavy petroleum fraction. The coal is broken to a medium particle size and is formed into a slurry with a heavy petroleum fraction such as a decanted oil having a boiling point of about 300.degree.-550.degree. C. The slurry is heated to a temperature of 400.degree.-500.degree. C. for a limited time of only about 1-5 minutes before cooling to a temperature of less than 300.degree. C. During this limited contact time at elevated temperature the slurry can be contacted with hydrogen gas to promote conversion. The liquid phase containing dispersed coal solids is filtered from the residual solids and recovered for use as a fuel or feed stock for other processes. The residual solids containing some carbonaceous material are further processed to provide hydrogen gas and heat for use as required in this process.

Vapor pressures and calculated heats of vaporization of concentrated nitric acid solutions in the composition range 71 to 89 percent nitrogen dioxide, 1 to 10 percent water, and in the temperature range 10 to 60 degrees C

NASA Technical Reports Server (NTRS)

Mckeown, A B; Belles, Frank E

1954-01-01

Total vapor pressures were measured for 16 acid mixtures of the ternary system nitric acid, nitrogen dioxide, and water within the temperature range 10 degrees to 60 degrees Celsius, and with the composition range 71 to 89 weight percent nitric acid, 7 to 20 weight percent nitrogen dioxide, and 1 to 10 weight percent water. Heats of vaporization were calculated from the vapor pressure measurements for each sample for the temperatures 25, 40, and 60 degrees Celsius. The ullage of the apparatus used for the measurements was 0.46. Ternary diagrams showing isobars as a function of composition of the system were constructed from experimental and interpolated data for the temperatures 25, 40, 45, and 60 degrees C and are presented herein.

High strength, tough alloy steel

DOEpatents

Thomas, Gareth; Rao, Bangaru V. N.

1979-01-01

A high strength, tough alloy steel is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other substitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

Heat transfer distributions induced by elevon deflections on swept wings and adjacent surfaces at Mach 6

NASA Technical Reports Server (NTRS)

Johnson, C. B.; Kaufman, L. G., II

1978-01-01

Surface heat transfer distributions are presented for swept wing semispan models having trailing edge elevon ramp angles of 0, 10, 20, and 30 degrees. The wing sweepback angles are 0, 50, and 70 degrees. The models have attachable cylindrical and flat plate center bodies and various attachable wing-tip fins. The data, obtained for a 0 degree angle of attack, a free stream Mach number of 6, and a wing root chord Reynolds number of about 17,000,000, reveal considerably larger regions of elevon induced thermal loads on adjacent surfaces than would be suggested by fully attached flow analyses.

Heat shock proteins in relation to heat stress tolerance of creeping bentgrass at different N levels.

PubMed

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

2014-01-01

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

Experimental study of turbulent flow heat transfer and pressure drop in a plate heat exchanger with chevron plates

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

Muley, A.; Manglik, R.M.

1997-07-01

Experimental data for isothermal pressure drop and heat transfer in single-phase water flows in a plate heat exchanger (PHE) with chevron plates are presented. A single-pass, U-type, counterflow PHE, with three different chevron plate arrangements is employed: two symmetric plate arrangements with {beta} = 30/30{degree} and 60/60{degree}, and a mixed-plate arrangement with {beta} = 30/60{degree}. With water flow rates in the turbulent flow regime (600 < Re < 10{sup 4} and 2 < Pr < 6), effects of the chevron corrugation inclination angle {beta} on Nu and f characteristics of the PHE are investigated. As {beta} increases and compared tomore » a flat-plate pack, up to 2 to 5 times higher Nu are obtained; the concomitant f, however, are 13 to 44 times higher. Based on the experimental data for Re {le} 1,000, predictive correlations of the form Nu = C{sub 1}{beta} Re{sup p1({beta})} Pr{sup 1/3} ({mu}/{mu}{sub w}){sup 0.14} and f = C{sub 2}{beta} Re{sup p2({beta})} are devised. Also, at constant pumping power and depending upon {beta}, the heat transfer is found to be enhanced over 1.8 times that in equivalent flat-plate channels.« less

Film cooling performance of a row of dual-fanned holes at various injection angles

NASA Astrophysics Data System (ADS)

Li, Guangchao; Wang, Haofeng; Zhang, Wei; Kou, Zhihai; Xu, Rangshu

2017-10-01

Film cooling performance about a row of dual-fanned holes with injection angles of 30°, 60 ° and 90° were experimentally investigated at blowing ratios of 1.0 and 2.0. Dual-fanned hole is a novel shaped hole which has both inlet expansion and outlet expansion. A transient thermochromic liquid crystal technique was used to reveal the local values of film cooling effectiveness and heat transfer coefficient. The results show that injection angles have strong influence on the two dimensional distributions of film cooling effectiveness and heat transfer coefficient. For the small injection angle of 30 degree and small blowing ratio of 1.0, there is only a narrow spanwise region covered with film. The increase of injection angle and blowing ratio both leads to the enhanced spanwise film diffusion, but reduced local cooling ability far away from the hole. Injection angles have comprehensive influence on the averaged film cooling effectiveness for various x/d locations. As injection angles are 30 and 60 degree, two bands of high heat transfer coefficients are found in mixing region of the gas and coolant. As injection angle increases to 90 degree, the mixing leads to the enhanced heat transfer region near the film hole. The averaged heat transfer coefficient increases with the increase of injection angle.

Inhibition of toxicogenic Bacillus cereus in rice-based foods by enterocin AS-48.

PubMed

Grande, Maria J; Lucas, Rosario; Abriouel, Hikmate; Valdivia, Eva; Omar, Nabil Ben; Maqueda, Mercedes; Martínez-Bueno, Manuel; Martínez-Cañamero, Magdalena; Gálvez, Antonio

2006-02-01

The antimicrobial effect of the broad-spectrum bacteriocin enterocin AS-48 against the toxicogenic psychrotrophic strain Bacillus cereus LWL1 has been investigated in a model food system consisting of boiled rice and in a commercial infant rice-based gruel dissolved in whole milk stored at temperatures of 37 degrees C, 15 degrees C and 6 degrees C. In food samples supplemented with enterocin AS-48 (in a concentration range of 20-35 mug/ml), viable cell counts decreased rapidly over incubation time, depending on the bacteriocin concentration, the temperature of incubation and the food sample. Enterotoxin production at 37 degrees C was also inhibited. Heat sensitivity of endospores increased markedly in food samples supplemented with enterocin AS-48: inactivation of endospores was achieved by heating for 1 min at 90 degrees C in boiled rice or at 95 degrees C in rice-based gruel. Activity of enterocin AS-48 in rice gruel was potentiated by sodium lactate in a concentration-dependent way.

Computed Temperature Distribution and Cooling of Solid Gas-Turbine Blades

NASA Technical Reports Server (NTRS)

Reuter, J. George; Gazley, Carl, Jr.

1947-01-01

Computations were made to determine the temperature distribution and cooling of solid gas-turbine blades.A range of temperatures was used from 1500 degrees to 2500 degrees F, blade-root temperatures from 100 degrees to 1000 degrees F, blade thermal conductivity from 8 to 220 BTU/(hr)(sq ft)(degrees F/ft), and net gas to metal heat transfer coefficients from 75 to 250 BTU/(hr)(sq ft)(degrees F).

Keeping Floodlight Temperature Low

NASA Technical Reports Server (NTRS)

Kiss, John

1987-01-01

Safety in explosive atmospheres enhanced. Retainer for floodlight designed to undergo relatively small temperature rise. Reaches no more than 350 degrees F (177 degrees C) with lamp operating at about 4,700 degrees F (2,600 degrees C). Satisfies 352 degrees F (188 degrees C) requirement for operation in some explosive atmospheres. Made of thermally conductive metal with coating of material having low thermal absorptivity/emissivity ratio so it conducts heat away from lamp and radiates to surroundings efficiently.

Thermodynamics of phenanthrene partition into solid organic matter from water.

PubMed

Chen, Bao-liang; Zhu, Li-zhong; Tao, Shu

2005-01-01

The thermodynamic behavior of organic contaminants in soils is essential to develop remediation technologies and assess risk from alternative technologies. Thermodynamics of phenanthrene partition into four solids(three soils and a bentonite) from water were investigated. The thermodynamics parameters (deltaH, deltaG degrees, deltaS degrees) were calculated according to experimental data. The total sorption heats of phenanthrene to solids from water ranged from -7.93 to -17.1 kJ/mol, which were less exothermic than the condensation heat of phenanthrene-solid (i.e., -18.6 kJ/mol). The partition heats of phenanthrene dissolved into solid organic matter ranged from 23.1 to 32.2 kJ/mol, which were less endothermic than the aqueous dissolved heat of phenanthrene (i.e., 40.2 kJ/mol), and were more endothermic than the fusion heat of phenanthrene-solid (i.e., 18.6 kJ/mol). The standard free energy changes, deltaG degrees, are all negative which suggested that phenanthrene sorption into solid was a spontaneous process. The positive values of standard entropy changes, deltaS degrees, show a gain in entropy for the transfer of phenanthrene at the stated standard state. Due to solubility-enhancement of phenanthrene, the partition coefficients normalized by organic carbon contents decrease with increasing system temperature (i.e., ln Koc = -0.284 ln S + 9.82 (n = 4, r2 = 0.992)). The solubility of phenanthrene in solid organic matter increased with increasing temperatures. Transports of phenanthrene in different latitude locations and seasons would be predicted according to its sorption thermodynamics behavior.

Testing the dynamic coupling of the core-mantle and inner core boundaries

NASA Astrophysics Data System (ADS)

Driscoll, Peter E.

2015-07-01

The proposal that the seismically observed hemispherical asymmetry of Earth's inner core is controlled by the heat flux structure imposed on the outer core by the lower mantle is tested with numerical dynamo models driven by mixed thermochemical convection. We find that models driven by a single core-mantle boundary (CMB) spherical harmonic of degree and mode 2, the dominant mode in lower mantle seismic shear velocity tomography, produce a similar structure at the inner core boundary (ICB) shifted 30∘ westward. The sensitivity of the ICB to the CMB is further tested by increasing the CMB heterogeneity amplitude. In addition, two seismic tomographic models are tested: first with CMB resolution up to degree and order 4, and second with resolution up to degree and order 8. We find time-averaged ICB heat flux in these cases to be similar at large scale, with small-scale differences due to higher CMB harmonics (above degree 4). The tomographic models produce "Earth-like" magnetic fields, while similar models with twice the CMB heat flow amplitudes produce less Earth-like fields, implying that increasing CMB heterogeneity forces the model out of an Earth-like regime. The dynamic ICB heat fluxes are compared to the proposed translation mode of the inner core to test whether the CMB controls inner core growth and structure. This test indicates that, although CMB tomography is unlikely to be driving inner core translation, the ICB heat flux response is weak enough to not interfere with the most unstable translation mode, if it is occurring.

Decreased heat tolerance is associated with hypothalamo-pituitary-adrenocortical axis impairment.

PubMed

Michel, V; Peinnequin, A; Alonso, A; Buguet, A; Cespuglio, R; Canini, F

2007-06-29

When rats are exposed to heat, they adapt themselves to the stressor with a wide inter-individual variability. Such differences in heat tolerance may be related to particularities in the hypothalamo-pituitary-adrenocortical (HPA) axis activation. To further this hypothesis, 80 rats instrumented with a telemetric device for abdominal temperature (Tabd) measurement were separated into two groups. Sixty-eight rats were exposed during 90 min at an ambient temperature of 40 degrees C, and 12 rats to an ambient temperature of 22 degrees C. Heat-exposed rats were then divided into three groups using the a posteriori k-means clustering method according to their Tabd level at the end of heat exposure. Heat tolerant rats (Tol, n=30) exhibiting the lowest Tabd showed a slight dehydration, a moderate triglyceride mobilization, but the highest plasma adrenocorticotropic-hormone (ACTH) and corticosterone levels. Conversely, heat exhausted rats (HE, n=14) presented the highest Tabd, a higher degree of dehydration, a greater metabolic imbalance with the lowest plasma triglyceride level and the highest lactate concentration, as well as a lowest plasma corticosterone and ACTH levels. The fact that the proopiomelanocortin (POMC) mRNA content within the pituitary was low despite of a high c-fos mRNA level is also relevant. Current inflammatory processes in HE rats were underlined by lower inhibitory factor kappaBalpha (IkappaBalpha) mRNA and higher tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) mRNA. In conclusion, data show that intolerance to heat exposure is associated to an HPA axis impairment, possibly related to changes occurring in the IkappaBalpha and TNF-alpha mRNA levels.

Quantification of the decay and re-induction of heat acclimation in dry-heat following 12 and 26 days without exposure to heat stress.

PubMed

Weller, Andrew S; Linnane, Denise M; Jonkman, Anna G; Daanen, Hein A M

2007-12-01

Compared with the induction of heat acclimation (HA), studies investigating the decay and re-induction of HA (RA) are relatively sparse and have yielded conflicting results. Therefore, 16 semi-nude men were acclimated to dry-heat by undertaking an exercise protocol in a hot chamber (dry-bulb temperature 46.1 +/- 0.1 degrees C; relative humidity 17.9 +/- 0.1%) on 10 consecutive days (HA1-10) in winter UK. Thereafter, the subjects were divided into two groups and re-exposed to the work-in-heat tests after 12 and 26 days until RA was attained (RA(12), n = 8; RA(26), n = 8). The exercise protocol consisted of 60 min of treadmill walking (1.53 m s(-1)) at an incline individually set to induce a rectal temperature (T (re)) of approximately 38.5 degrees C during HA1 (equating to 45 +/- 4% peak oxygen uptake), followed by 10 min of rest and 40 min of further treadmill exercise, the intensity of which was increased across HA to maintain T(re )at approximately 38.5 degrees C. T(re), mean skin temperature, heart rate and rate of total water loss measured at 60 min did not change after HA7, and HA was taken as the mean of the responses during HA8-10. For both groups, there was no decay in T(re) and for all measured variables RA was attained after 2 and 4 days in RA(12) and RA(26), respectively. It is concluded that once adaptation to heat has been attained, the time that individuals may spend in cooler conditions before returning to a hot environment could be as long as one month, without the need for extensive re-adaptation to heat.

Evaluation of solar gain through skylights for inclusion in the SP53 residential building loads data base

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

Hanford, J.W.; Huang, Y.J.

The energy performance of skylights is similar to that of windows in admitting solar heat gain, while at the same time providing a pathway for convective and conductive heat transfer through the building envelope. Since skylights are typically installed at angles ranging from 0{degrees} to 45{degrees}, and differ from windows in both their construction and operation, their conductive and convective heat gains or losses, as well as solar heat gain, will differ for the same rough opening and thermal characteristics. The objective of this work is to quantify the impact of solar gain through skylights on building heating and coolingmore » loads in 45 climates, and to develop a method for including these data into the SP53 residential loads data base previously developed by LBL in support of DOE`s Automated Residential Energy Standard (ARES) program. The authors used the DOE-2.1C program to simulate the heating and cooling loads of a prototypical residential building while varying the size and solar characteristics of skylights and windows. The results are presented as Skylight Solar Loads, which are the contribution of solar gains through skylights to the overall building heating and cooling loads, and as Skylight Solar Load Ratios, which are the ratios of skylight solar loads to those for windows with the same orientation. The study shows that skylight solar loads are larger than those for windows in both heating and cooling. Skylight solar cooling loads are from three to four times greater than those for windows regardless of the skylight tilt, except for those facing north. These cooling loads are largest for south-facing skylights at a tilt angle of approximately 20{degrees}, and drop off at higher tilts and other orientations.« less

Drink temperature influences fluid intake and endurance capacity in men during exercise in a hot, dry environment.

PubMed

Mündel, Toby; King, Jenny; Collacott, Esther; Jones, David A

2006-09-01

The effect of different drink temperatures on the perception of exertion and exercise endurance has not been extensively investigated. Consequently, the purpose of the present study was to examine the effect of drink temperature on fluid intake and endurance during cycling in the heat. Eight healthy, non-acclimated males (26 +/- 7 years; maximum oxygen uptake, 54 +/- 5 ml kg(-1) min(-1); mean +/- S.D.) cycled to exhaustion at 34 degrees C and at 65% of their peak aerobic power, consuming a drink at either 19 degrees C (CON) or 4 degrees C (COLD). Six of the eight subjects cycled for longer during COLD, with exhaustion occurring at 62 +/- 4 min, compared to 55 +/- 4 min for CON (P < 0.05; mean +/- S.E.M.). Subjects consumed significantly more fluid during COLD compared to CON (1.3 +/- 0.3 l h(-1) compared to 1.0 +/- 0.2 l h(-1); P < 0.05). Heart rate tended to be lower by approximately 5 beats min(-1) during COLD, and rectal temperature during the second half of the exercise period was approximately 0.25 degrees C lower during the COLD trial; however, these trends were not significant (P = 0.08 and P = 0.07, respectively). No differences were observed between trials for ventilation, concentrations of prolactin, glucose and lactate or perceived exertion. It is concluded that a drink at 4 degrees C during exercise in the heat enhances fluid consumption and improves endurance by acting as a heat sink, attenuating the rise in body temperature and therefore reducing the effects of heat stress.

Salicylic acid alleviates decreases in photosynthesis under heat stress and accelerates recovery in grapevine leaves.

PubMed

Wang, Li-Jun; Fan, Ling; Loescher, Wayne; Duan, Wei; Liu, Guo-Jie; Cheng, Jian-Shan; Luo, Hai-Bo; Li, Shao-Hua

2010-02-23

Although the effect of salicylic acid (SA) on photosynthesis of plants including grapevines has been investigated, very little is yet known about the effects of SA on carbon assimilation and several components of PSII electron transport (donor side, reaction center and acceptor side). In this study, the impact of SA pretreatment on photosynthesis was evaluated in the leaves of young grapevines before heat stress (25 degrees C), during heat stress (43 degrees C for 5 h), and through the following recovery period (25 degrees C). Photosynthetic measures included gas exchange parameters, PSII electron transport, energy dissipation, and Rubisco activation state. The levels of heat shock proteins (HSPs) in the chloroplast were also investigated. SA did not significantly (P < 0.05) influence the net photosynthesis rate (Pn) of leaves before heat stress. But, SA did alleviate declines in Pn and Rubisco activation state, and did not alter negative changes in PSII parameters (donor side, acceptor side and reaction center QA) under heat stress. Following heat treatment, the recovery of Pn in SA-treated leaves was accelerated compared with the control (H2O-treated) leaves, and, donor and acceptor parameters of PSII in SA-treated leaves recovered to normal levels more rapidly than in the controls. Rubisco, however, was not significantly (P < 0.05) influenced by SA. Before heat stress, SA did not affect level of HSP 21, but the HSP21 immune signal increased in both SA-treated and control leaves during heat stress. During the recovery period, HSP21 levels remained high through the end of the experiment in the SA-treated leaves, but decreased in controls. SA pretreatment alleviated the heat stress induced decrease in Pn mainly through maintaining higher Rubisco activation state, and it accelerated the recovery of Pn mainly through effects on PSII function. These effects of SA may be related in part to enhanced levels of HSP21.

Cold and heat strain during cold-weather field training with nuclear, biological, and chemical protective clothing.

PubMed

Rissanen, Sirkka; Rintamäki, Hannu

2007-02-01

The objective of this study was to quantify the thermal strain of soldiers wearing nuclear, biological, and chemical protective clothing during short-term field training in cold conditions. Eleven male subjects performed marching exercises at moderate and heavy activity levels for 60 minutes. Rectal temperature (Tre), skin temperatures, and heart rate were monitored. Ambient temperature (Ta) varied from -33 to 0 degrees C. Tre was affected by changes in metabolism, rather than in Ta. Tre increased above 38 degrees during heavy exercise even at -33 degrees C. The mean skin temperature decreased to tolerance level (25 degrees C) at Ta below -25 degrees C with moderate exercise. Finger temperature decreased below 15 degrees C (performance degradation) at Ta of -15 degrees C or cooler. The present results from the field confirm the previous results based on laboratory studies and show that risk of both heat and cold strain is evident, with cooling of extremities being most critical, while wearing nuclear, biological, and chemical protective clothing during cold-weather training.

High temperature metal hydrides as heat storage materials for solar and related applications.

PubMed

Felderhoff, Michael; Bogdanović, Borislav

2009-01-01

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

Lactobacillus crustorum KH: novel prospective probiotic strain isolated from Iranian traditional dairy products.

PubMed

Sharafi, Hakimeh; Derakhshan, Venos; Paknejad, Mojgan; Alidoust, Leila; Tohidi, Azadeh; Pornour, Majid; Hajfarajollah, Hamidreza; Zahiri, Hossein Shahbani; Noghabi, Kambiz Akbari

2015-02-01

In recent years, exploring novel probiotic strains for therapeutic intervention has been raised due to the significant increase in market demand. This study aimed to investigate the certain probiotic properties of 15 Lactobacillus isolates from Iranian traditional dairy products. Among them, a novel potential probiotic strain was isolated and identified as Lactobacillus crustorum. The characteristics of potential probiotics were examined in terms of resistance to acidity, bile, and salinity as well as antibiotic tolerance and antibacterial activity. L. crustorum KH has shown tolerance property to bile (0.3 % w), acidity (pH 2-9), and salinity (1-5 % NaCl) and strong antibacterial activity against tested enteropathogens by well-diffusion assay. Furthermore, in vivo study and histological assays were performed to study whether live and heat-killed cells of L. crustorum KH are able to protect against the challenge of Escherichia coli O157:H7 in the gastrointestinal tract of mice used as an experimental model. Therefore, heat-killed and live cells of L. crustorum KH were inoculated by gavage to different groups of 4-6-week-old female BALB/c mice in doses of 10(8) colony-forming unit (CFU)/dose. Thereafter, these mice were challenged with E. coli O157:H7 also inoculated in the gastrointestinal tract (GIT) of the animals. The results showed that heat-killed cells of L. crustorum KH exert a protective effect against E. coli O157:H7 colonization at different degrees, being lower than that produced by viable cells.

Forecasting decadal changes in sea surface temperatures and coral bleaching within a Caribbean coral reef

NASA Astrophysics Data System (ADS)

Li, Angang; Reidenbach, Matthew A.

2014-09-01

Elevated sea surface temperature (SST) caused by global warming is one of the major threats to coral reefs. While increased SST has been shown to negatively affect the health of coral reefs by increasing rates of coral bleaching, how changes to atmospheric heating impact SST distributions, modified by local flow environments, has been less understood. This study aimed to simulate future water flow patterns and water surface heating in response to increased air temperature within a coral reef system in Bocas del Toro, Panama, located within the Caribbean Sea. Water flow and SST were modeled using the Delft3D-FLOWcomputer simulation package. Locally measured physical parameters, including bathymetry, astronomic tidal forcing, and coral habitat distribution were input into the model and water flow, and SST was simulated over a four-month period under present day, as well as projected warming scenarios in 2020s, 2050s, and 2080s. Changes in SST, and hence the thermal stress to corals, were quantified by degree heating weeks. Results showed that present-day reported bleaching sites were consistent with localized regions of continuous high SST. Regions with highest SST were located within shallow coastal sites adjacent to the mainland or within the interior of the bay, and characterized by low currents with high water retention times. Under projected increases in SSTs, shallow reef areas in low flow regions were found to be hot spots for future bleaching.

Warming and the dependence of limber pine (Pinus flexilis) establishment on summer soil moisture within and above its current elevation range

USGS Publications Warehouse

Moyes, Andrew B.; Castanha, Cristina; Germino, Matthew J.; Kueppers, Lara M.

2013-01-01

Continued changes in climate are projected to alter the geographic distributions of plant species, in part by affecting where individuals can establish from seed. We tested the hypothesis that warming promotes uphill redistribution of subalpine tree populations by reducing cold limitation at high elevation and enhancing drought stress at low elevation. We seeded limber pine (Pinus flexilis) into plots with combinations of infrared heating and water addition treatments, at sites positioned in lower subalpine forest, the treeline ecotone, and alpine tundra. In 2010, first-year seedlings were assessed for physiological performance and survival over the snow-free growing season. Seedlings emerged in midsummer, about 5–8 weeks after snowmelt. Low temperature was not observed to limit seedling photosynthesis or respiration between emergence and October, and thus experimental warming did not appear to reduce cold limitation at high elevation. Instead, gas exchange and water potential from all sites indicated a prevailing effect of summer moisture stress on photosynthesis and carbon balance. Infrared heaters raised soil growing degree days (base 5 °C, p p 3 m-3 consistently corresponded with moderate and severe indications of drought stress in midday stem water potential, stomatal conductance, photosynthesis, and respiration. Seedling survival was greater in watered plots than in heated plots (p = 0.01), and negatively related to soil growing degree days and duration of exposure to θ 3 m-3 in a stepwise linear regression model (p < 0.0001). We concluded that seasonal moisture stress and high soil surface temperature imposed a strong limitation to limber pine seedling establishment across a broad elevation gradient, including at treeline, and that these limitations are likely to be enhanced by further climate warming.

Recovery from adverse effects of heat stress on slow-growing chicks in the tropics 1: Effect of ascorbic acid and different levels of betaine.

PubMed

Attia, Y A; Hassan, R A; Qota, E M A

2009-06-01

Three hundreds, 21 d-old slow-growing chicks were randomly divided among 5 treatments, of 5 replicates each. Each replicate contained 12 unsexed chicks housed in (1 x 1) a floor pen. A group was kept under thermoneutral condition at 28 +/- 4 degrees C and RH was 55 +/- 3% during 21-84 d of age (positive control) and fed corn-soybean meal diet. The other four groups were kept for three successive days per week under heat stress (HS) at 38 +/- 1.4 degrees C and 49 +/- 2% RH from 12.00 to 16.00 pm. Chicks in HS treatments were fed corn-soybean meal diet without (negative control) or with 250 mg AA/kg diet and Bet at 0.5 and 1 g/kg diet. HS decreased productive performance, increased (P < 0.05) meat dry matter, plasma triglyceride and serum calcium whereas decreased (P > 0.05) plasma glucose, serum total protein and water holding capacity (WHC) of meat. AA and 1 g of Bet/kg diet was equally potent for partial relief (P < 0.05) of the negative effect of HS on growth, increased (P < 0.05) feed intake, protein digestibility (P < 0.05), dressing out percentage, liver and giblets, whilst improved (P < 0.05) feed conversion ratio (FCR). Also, a complete recovery from the negative effect (P < 0.05) of HS shown on plasma glucose and partial recovery (P < 0.05) observed in total protein, triglyceride, blood pH, packed cell volume (PCV), hemoglobin (Hgb), rectal temperature (RT) and respiration rate (RR) and improved humoral immune competence to sheep red blood cell (SBRCs) test.

Multi-Cultural Competency-Based Vocational Curricula. Maintenance Mechanics. Multi-Cultural Competency-Based Vocational/Technical Curricula Series.

ERIC Educational Resources Information Center

Hepburn, Larry; Shin, Masako

This document, one of eight in a multi-cultural competency-based vocational/technical curricula series, is on maintenance mechanics. This program is designed to run 40 weeks and cover 5 instructional areas: basic electricity (14 weeks); maintenance and repair of heating (4 weeks); maintenance and repair of air conditioning (12 weeks); maintenance…

Cupping for treating neck pain in video display terminal (VDT) users: a randomized controlled pilot trial.

PubMed

Kim, Tae-Hun; Kang, Jung Won; Kim, Kun Hyung; Lee, Min Hee; Kim, Jung Eun; Kim, Joo-Hee; Lee, Seunghoon; Shin, Mi-Suk; Jung, So-Young; Kim, Ae-Ran; Park, Hyo-Ju; Hong, Kwon Eui

2012-01-01

This was a randomized controlled pilot trial to evaluate the effectiveness of cupping therapy for neck pain in video display terminal (VDT) workers. Forty VDT workers with moderate to severe neck pain were recruited from May, 2011 to February, 2012. Participants were randomly allocated into one of the two interventions: 6 sessions of wet and dry cupping or heating pad application. The participants were offered an exercise program to perform during the participation period. A 0 to 100 numeric rating scale (NRS) for neck pain, measure yourself medical outcome profile 2 score (MYMOP2 score), cervical spine range of motion (C-spine ROM), neck disability index (NDI), the EuroQol health index (EQ-5D), short form stress response inventory (SRI-SF) and fatigue severity scale (FSS) were assessed at several points during a 7-week period. Compared with a heating pad, cupping was more effective in improving pain (adjusted NRS difference: -1.29 [95% CI -1.61, -0.97] at 3 weeks (p=0.025) and -1.16 [-1.48, -0.84] at 7 weeks (p=0.005)), neck function (adjusted NDI difference: -0.79 [-1.11, -0.47] at 3 (p=0.0039) and 7 weeks (p<0.0001)) and discomfort (adjusted MYMOP2 difference score: -0.72 [-1.04 to -0.40] at 3 weeks and -0.92 [-1.24, -0.60] at 7 weeks). Significant improvement in EQ-5D was observed at 7 weeks (1.0 [0.88, 1.0] with cupping and 0.91 [0.86, 0.91] with heating pad treatment, p=0.0054). Four participants reported mild adverse events of cupping. Two weeks of cupping therapy and an exercise program may be effective in reducing pain and improving neck function in VDT workers.

Hot and Cold Drugs: National Park Service Medication Stability at the Extremes of Temperature.

PubMed

Armenian, Patil; Campagne, Danielle; Stroh, Geoff; Ives Tallman, Crystal; Zeng, William Z D; Lin, Thomas; Gerona, Roy R

2017-01-01

National Park Service (NPS) Parkmedics provide medical care in austere environments. The objective of this study was to evaluate the stability of specific medications used by Parkmedics at extremes of temperatures likely to be faced in the field. This is a bench research study conducted in the laboratory setting over a 4-week period. Parenteral medications were separated into 4 temperature exposure groups: A) 45°C (hot); B) -20°C (cold); C) hot then cold temperatures alternating weekly; and D) cold then hot temperatures alternating weekly. At study start and the end of each week, three aliquots from each group were sampled to determine the remaining drug concentration through liquid chromatography-quadrupole time-of-flight mass spectrometry (Agilent LC 1260- QTOF/MS 6550). Quantitative analysis was done using Agilent MassHunter Quantitative Analysis software. The mean drug concentration from triplicate aliquots was expressed as percentage of its baseline concentration to monitor the drug's stability during storage. Eight medications were analyzed (atropine, diphenhydramine, fentanyl, hydromorphone, midazolam, morphine, naloxone, ondansetron). Hydromorphone, morphine, and ondansetron showed the greatest stability, at above 90% of original concentration in all study arms. Diphenhydramine, fentanyl and midazolam showed heat independent degradation, degrading the same way regardless of heat exposure. By the end of the study period, 51-56% midazolam remained in all groups. Atropine and naloxone showed heat dependent degradation, degrading more when exposed to heat. Atropine had the most degradation, being undetectable after 4 weeks of heat exposure. We recommend that EMS providers replace atropine, naloxone, diphenhydramine, fentanyl, and midazolam frequently if they are practicing in low call volume or high-temperature environments. Further studies will be needed to determine if re-dosing midazolam, naloxone, and atropine is the appropriate clinical strategy in this setting if adequate clinical effect is not reached with a single dose.

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems.

PubMed

Hashiguchi, Nobuko; Tochihara, Yutaka; Ohnaka, Tadakatsu; Tsuchida, Chiaki; Otsuki, Tamio

2004-11-01

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.

Stability of rifabutin in two extemporaneously compounded oral liquids.

PubMed

Haslam, J L; Egodage, K L; Chen, Y; Rajewski, R A; Stella, V

1999-02-15

The stability of rifabutin 20 mg/mL in two oral liquids was studied. Powder from 100 150-mg rifabutin capsules was placed in a glass mortar. Cherry syrup (pH 2.9) or a 1:1 mixture of Ora-Sweet and Ora-Plus (Paddock Laboratories) was added to produce 750 mL of each formulation, which was then stored in 2-oz plastic prescription bottles. Three bottles of each formulation were stored at 4, 25, 30, and 40 degrees C. At 0, 1, 2, 4, 8, and 12 weeks, the bottles were collected and allowed to remain at room temperature for one hour; samples of about 1 mL were collected from each bottle, weighed, and assayed for rifabutin content by high-performance liquid chromatography. The rifabutin liquids prepared with cherry syrup and stored at 4, 25, and 30 degrees C lost a mean of < 8% of the initial drug concentration during the 12-week study; at 40 degrees C, the liquids lost > 10% of the initial drug concentration by 12 weeks. There was a mean loss of < 5% of the initial rifabutin concentration in all the liquids prepared with Ora-Sweet and Ora-Plus. The liquid prepared with cherry syrup, upon standing, showed a tendency for some of the ingredients to float. The suspension prepared with Ora-Sweet and Ora-Plus had a tendency to retain bubbles after it was shaken, but the ingredients did not settle upon standing. Rifabutin 20 mg/mL in two extemporaneously compounded oral liquids prepared from capsules and sweetened vehicles was stable for at least 12 weeks at 4, 25, 30, and 40 degrees C with the exception of rifabutin in cherry syrup, which was stable for only 8 weeks at 40 degrees C.

Kinetic Growth Rate after Portal Vein Embolization Predicts Posthepatectomy Outcomes: Toward Zero Liver-Related Mortality in Patients with Colorectal Liver Metastases and Small Future Liver Remnant

PubMed Central

Shindoh, Junichi; Truty, Mark J; Aloia, Thomas A; Curley, Steven A; Zimmitti, Giuseppe; Huang, Steven Y; Mahvash, Armeen; Gupta, Sanjay; Wallace, Michael J; Vauthey, Jean-Nicolas

2013-01-01

Background Standardized future liver remnant (sFLR) volume and degree of hypertrophy after portal vein embolization (PVE) have been recognized as significant predictors of surgical outcomes after major liver resection. However, regeneration rate of the FLR after PVE varies among individuals and its clinical significance is unknown. Study Design Degree of hypertrophy at initial volume assessment divided by number of weeks elapsed after PVE was defined as the kinetic growth rate (KGR). In 107 consecutive patients who underwent liver resection for colorectal liver metastases with a sFLR volume of greater than 20%, the ability of the KGR to predict overall and liver-specific postoperative morbidity and mortality was compared with sFLR volume and degree of hypertrophy. Results Using receiver operating characteristic analysis, the best cut-off values for sFLR volume, degree of hypertrophy, and KGR for predicting postoperative hepatic insufficiency were estimated as, respectively, 29.6%, 7.5%, and 2.0% per week. Among these, KGR was the most accurate predictor (area under the curve, 0.830 [0.736-0.923]; asymptotic significance, 0.002). KGR of less than 2% per week vs. ≥2% per week correlate with rates of hepatic insufficiency (21.6% vs. 0%, p = 0.0001) and liver-related 90-day mortality (8.1% vs. 0%, P=0.04). The predictive value of KGR was not influenced by sFLR volume or the timing of initial volume assessment when evaluated within 8 weeks after PVE. Conclusions KGR is a better predictor of postoperative morbidity and mortality after liver resection for small FLR than conventional measured volume parameters (sFLR volume and degree of hypertrophy). PMID:23219349

Kinetic growth rate after portal vein embolization predicts posthepatectomy outcomes: toward zero liver-related mortality in patients with colorectal liver metastases and small future liver remnant.

PubMed

Shindoh, Junichi; Truty, Mark J; Aloia, Thomas A; Curley, Steven A; Zimmitti, Giuseppe; Huang, Steven Y; Mahvash, Armeen; Gupta, Sanjay; Wallace, Michael J; Vauthey, Jean-Nicolas

2013-02-01

Standardized future liver remnant (sFLR) volume and degree of hypertrophy after portal vein embolization (PVE) have been recognized as important predictors of surgical outcomes after major liver resection. However, the regeneration rate of the FLR after PVE varies among individuals and its clinical significance is unknown. Kinetic growth rate (KGR) is defined as the degree of hypertrophy at initial volume assessment divided by number of weeks elapsed after PVE. In 107 consecutive patients who underwent liver resection for colorectal liver metastases with an sFLR volume >20%, the ability of the KGR to predict overall and liver-specific postoperative morbidity and mortality was compared with sFLR volume and degree of hypertrophy. Using receiver operating characteristic analysis, the best cutoff values for sFLR volume, degree of hypertrophy, and KGR for predicting postoperative hepatic insufficiency were estimated as 29.6%, 7.5%, and 2.0% per week, respectively. Among these, KGR was the most accurate predictor (area under the curve 0.830 [95% CI, 0.736-0.923]; asymptotic significance, 0.002). A KGR of <2% per week vs ≥2% per week correlates with rates of hepatic insufficiency (21.6% vs 0%; p = 0.0001) and liver-related 90-day mortality (8.1% vs 0%; p = 0.04). The predictive value of KGR was not influenced by sFLR volume or the timing of initial volume assessment when evaluated within 8 weeks after PVE. Kinetic growth rate is a better predictor of postoperative morbidity and mortality after liver resection for small FLR than conventional measured volume parameters (ie, sFLR volume and degree of hypertrophy). Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

National Geothermal Academy. Geo-Heat Center Quarterly Bulletin, Vol. 31 No. 2 (Complete Bulletin). A Quarterly Progress and Development Report on the Direct Utilization of Geothermal Resources

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

Boyd, Tonya; Maddi, Phillip

2012-08-01

The National Geothermal Academy (NGA) is an intensive 8-week overview of the different aspects involved in developing a geothermal project, hosted at University of Nevada, Reno. The class of 2012 was the second graduating class from the academy and included 21 students from nine states, as well as Saudi Arabia, Dominica, India, Trinidad, Mexico. The class consisted of people from a wide range of scholastic abilities from students pursuing a Bachelor’s or Master’s degrees, to entrepreneurs and professionals looking to improve their knowledge in the geothermal field. Students earned 6 credits, either undergraduate or graduate, in engineering or geology. Overall,more » the students of the NGA, although having diverse backgrounds in engineering, geology, finance, and other sciences, came together with a common passion to learn more about geothermal.« less

Heat exhaustion in a deep underground metalliferous mine.

PubMed

Donoghue, A M; Sinclair, M J; Bates, G P

2000-03-01

To examine the incidence, clinical state, personal risk factors, haematology, and biochemistry of heat exhaustion occurring at a deep underground metalliferous mine. To describe the underground thermal conditions associated with the occurrence of heat exhaustion. A 1 year prospective case series of acute heat exhaustion was undertaken. A history was obtained with a structured questionnaire. Pulse rate, blood pressure, tympanic temperature, and specific gravity of urine were measured before treatment. Venous blood was analysed for haematological and biochemical variables, during the acute presentation and after recovery. Body mass index (BMI) and maximum O2 consumption (VO2 max) were measured after recovery. Psychrometric wet bulb temperature, dry bulb temperature, and air velocity were measured at the underground sites where heat exhaustion had occurred. Air cooling power and psychrometric wet bulb globe temperature were derived from these data. 106 Cases were studied. The incidence of heat exhaustion during the year was 43.0 cases/million man-hours. In February it was 147 cases/million man-hours. The incidence rate ratio for mines operating below 1200 m compared with those operating above 1200 m was 3.17. Mean estimated fluid intake was 0.64 l/h (SD 0.29, range 0.08-1.50). The following data were increased in acute presentation compared with recovery (p value, % of acute cases above the normal clinical range): neutrophils (p < 0.001, 36%), anion gap (p < 0.001, 63%), urea (p < 0.001, 21%), creatinine (p < 0.001, 30%), glucose (p < 0.001, 15%), serum osmolality (p = 0.030, 71%), creatine kinase (p = 0.002, 45%), aspartate transaminase (p < 0.001, 14%), lactate dehydrogenase (p < 0.001, 9.5%), and ferritin (p < 0.001, 26%). The following data were depressed in acute presentation compared with recovery (p value, % of acute cases below the normal clinical range): eosinophils (p = 0.003, 38%) and bicarbonate (p = 0.011, 32%). Urea and creatinine were significantly increased in miners with heat cramps compared with miners without this symptom (p < 0.001), but there was no significant difference in sodium concentration (p = 0.384). Mean psychrometric wet bulb temperature was 29.0 degrees C (SD 2.2, range 21.0-34.0). Mean dry bulb temperature was 37.4 degrees C (SD 2.4, range 31.0-43.0). Mean air velocity was 0.54 m/s (SD 0.57, range 0.00-4.00). Mean air cooling power was 148 W/m2 (SD 49, range 33-290) Mean psychrometric wet bulb globe temperature was 31.5 degrees C (SD 2.0, range 25.2-35.3). Few cases (< 5%) occurred at psychrometric wet bulb temperature < 25.0 degrees C, dry bulb temperature < 33.8 degrees C, air velocity > 1.56 m/s, air cooling power > 248 W/m2, or psychrometric wet bulb globe temperature < 28.5 degrees C. Heat exhaustion in underground miners is associated with dehydration, neutrophil leukocytosis, eosinopenia, metabolic acidosis, increased glucose and ferritin, and a mild rise in creatine kinase, aspartate transaminase, and lactate dehydrogenase. Heat cramps are associated with dehydration but not hyponatraemia. The incidence of heat exhaustion increases during summer and at depth. An increased fluid intake is required. Heat exhaustion would be unlikely to occur if ventilation and refrigeration achieved air cooling power > 250 W/m2 at all underground work sites.

Adequacy of solar energy to keep babies warm.

PubMed

Daga, S R; Sequera, D; Goel, S; Desai, B; Gajendragadkar, A

1996-02-01

Solar energy could be used as an alternate energy source for keeping neonates warm especially in tropical countries. The present study investigated the efficacy of solar powered room heating system. Referral center for neonatal care. A fluid system heated by solar panels and circulated into a room was used to maintain room temperature. A servocontrolled heating device was used to regulate and maintain desired room temperature. Neonatal rectal temperature and room temperature. Infants between 1750-2250 g were observed to require a mean room temperature of 32.5 degrees C to maintain normothermia. In 85 infants less than 1500 g, of the 5050 infant temperature records, only 3% showed a record less than 36 degrees C. Solar powered room heating is effective in maintaining infant temperature and is cost-effective as compared to the existing warming devices.

Method and apparatus for making uniform pellets for fusion reactors

DOEpatents

Budrick, Ronald G.; King, Frank T.; Martin, Alfred J.; Nolen, Jr., Robert L.; Solomon, David E.

1977-01-01

A method and apparatus for making uniform pellets for laser driven fusion reactors which comprises selection of a quantity of glass frit which has been accurately classified as to size within a few micrometers and contains an occluded material, such as urea, which gasifies and expands when heated. The sized particles are introduced into an apparatus which includes a heated vertical tube with temperatures ranging from 800.degree. C to 1300.degree. C. The particles are heated during the drop through the tube to molten condition wherein the occluded material gasifies to form hollow microspheres which stabilize in shape and plunge into a collecting liquid at the bottom of the tube. The apparatus includes the vertical heat resistant tube, heaters for the various zones of the tube and means for introducing the frit and collecting the formed microspheres.

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

PubMed

Whiting, Joshua; Sacks, Richard

2003-05-15

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

Relationship between accumulated heat stress during the dry period, body condition score, and reproduction parameters of Holstein cows in tropical conditions.

PubMed

Avendaño-Reyes, Leonel; Fuquay, John W; Moore, Reuben B; Liu, Zhanglin; Clark, Bruce L; Vierhout, C

2010-02-01

To estimate the relationship between heat stress during the last 60 days prepartum, body condition score and certain reproductive traits in the subsequent lactation of Holstein cows, 564 multiparous cows and 290 primiparous cows from four dairy herds were used in a hot, humid region. Maximum prepartum degree days were estimated to quantify the degree of heat stress. Multiple regressions analyses and logistic regression analysis were performed to determine the effect of prepartum heat stress and body condition change on reproductive parameters, which were obtained from DHIA forms at the end of the lactation. Multiparous and primiparous cows which gained body condition score from calving to 60 d postpartum exhibited 28 and 27 fewer days open (P < 0.05), respectively, than cows not gaining. There was no effect (P > 0.05) of heat stress measurement on days open or services per conception in either multiparous or primiparous cows. During hotter months of calving, multiparous cows showed higher services per conception and primiparous cows showed higher days open and services per conception (P < 0.05). Maximum prepartum degree-days were positively associated (P < 0.05) with calving difficulty score. Multiparous cows with high body condition score at calving were 1.47 times more likely to present a very difficult calving than cows that calved in October (P < 0.05). Collectively, these results suggest that reproductive performance was not affected by cumulative prepartum heat stress although it was associated with very difficult calving score.

Changes in forearm muscle temperature alter renal vascular responses to isometric handgrip.

PubMed

Kuipers, Nathan T; Sauder, Charity L; Kearney, Matthew L; Ray, Chester A

2007-12-01

The purpose of the present study was to examine the effect of heating and cooling the forearm muscles on renal vascular responses to ischemic isometric handgrip (IHG). It was hypothesized that heating and cooling the forearm would augment and attenuate, respectively, renal vascular responses to IHG. Renal vascular responses to IHG were studied during forearm heating at 39 degrees C (n = 15, 26 +/- 1 yr) and cooling at 26 degrees C (n = 12, 26 +/- 1 yr). For a control trial, subjects performed the experimental protocol while the forearm was normothermic (approximately 34 degrees C). Muscle temperature (measured by intramuscular probe) was controlled by changing the temperature of water cycling through a water-perfused sleeve. The experimental protocol was as follows: 3 min at baseline, 1 min of ischemia, ischemic IHG to fatigue, and 2 min of postexercise muscle ischemia. At rest, renal artery blood velocity (RBV; Doppler ultrasound) and renal vascular conductance (RVC = RBV/mean arterial blood pressure) were not different between normothermia and the two thermal conditions. During ischemic IHG, there were greater decreases in RBV and RVC in the heating trial. However, RBV and RVC were similar during postexercise muscle ischemia during heating and normothermia. RVC decreased less during cooling than in normothermia while the subjects performed the ischemic IHG protocol. During postexercise muscle ischemia, RVC was greater during cooling than in normothermia. These results indicate that heating augments mechanoreceptor-mediated renal vasoconstriction whereas cooling blunts metaboreceptor-mediated renal vasoconstriction.

Pre-Monsoon Drought and Heat Waves in India

NASA Image and Video Library

2015-09-12

In June 2015, news organizations around the world reported on a deadly heat wave in India that killed more than 2,300 people. Prior to the arrival of the summer monsoon in India, weather conditions had been extremely hot and dry. Such conditions can lead to economic and agricultural disaster, human suffering and loss of life. NASA satellite sensors are allowing scientists to characterize pre-monsoon droughts and heat waves and postulate their scientific cause. This figure shows the longitude-time variations, averaged between 21 and 22 degrees North, across the middle of the India subcontinent from mid-April to mid-June. Longitude from the Arabian Sea to the Bay of Bengal is represented on the horizontal axis; while the vertical axis shows the timeframe. Rainfall is shown on the left, soil moisture is in the center, and surface air temperature is on the right. For both years (2012 and 2015), the summer monsoon begins in June, with sharp rises in rainfall and soil moisture, and a sharp drop in air temperature. The hottest and driest weeks occurred just before the summer monsoon onsets. Similar dry and hot periods, varying from one to a few weeks, were observed in 2013 and 2014. Soil moisture as an indication of drought as measured by NASA's Aquarius mission was first available in 2012. Rainfall data are from NASA's Tropical Rainfall Measuring Mission (TRMM), and surface air temperature is from NASA's Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite. The TRMM and Aquarius missions ended in April 2015, before the drought and heat waves. Their data were replaced by those presently available from NASA's Soil Moisture Active Passive Mission (SMAP) and Global Precipitation Mission (GPM) to show the drought and heatwave in 2015. Scientists from NASA's Jet Propulsion Laboratory, Pasadena, California, have shown that during the summer monsoon season, moisture is transported into the India Subcontinent from the Arabian Sea and out to the Bay of Bengal. The difference between moisture input from the west and output to the east is deposited as rain over land. The pre-monsoon drought and heat waves coincide with the short period when moisture is advected out to the Bay of Bengal ahead of input from the Arabian Sea. The onset of southwest monsoon winds begins in the Bay of Bengal and sucks moisture out from the subcontinent earlier than the onset in the Arabian Sea. http://photojournal.jpl.nasa.gov/catalog/PIA19939

Methods to Estimate Acclimatization to Urban Heat Island Effects on Heat- and Cold-Related Mortality.

PubMed

Milojevic, Ai; Armstrong, Ben G; Gasparrini, Antonio; Bohnenstengel, Sylvia I; Barratt, Benjamin; Wilkinson, Paul

2016-07-01

Investigators have examined whether heat mortality risk is increased in neighborhoods subject to the urban heat island (UHI) effect but have not identified degrees of difference in susceptibility to heat and cold between cool and hot areas, which we call acclimatization to the UHI. We developed methods to examine and quantify the degree of acclimatization to heat- and cold-related mortality in relation to UHI anomalies and applied these methods to London, UK. Case-crossover analyses were undertaken on 1993-2006 mortality data from London UHI decile groups defined by anomalies from the London average of modeled air temperature at a 1-km grid resolution. We estimated how UHI anomalies modified excess mortality on cold and hot days for London overall and displaced a fixed-shape temperature-mortality function ("shifted spline" model). We also compared the observed associations with those expected under no or full acclimatization to the UHI. The relative risk of death on hot versus normal days differed very little across UHI decile groups. A 1°C UHI anomaly multiplied the risk of heat death by 1.004 (95% CI: 0.950, 1.061) (interaction rate ratio) compared with the expected value of 1.070 (1.057, 1.082) if there were no acclimatization. The corresponding UHI interaction for cold was 1.020 (0.979, 1.063) versus 1.030 (1.026, 1.034) (actual versus expected under no acclimatization, respectively). Fitted splines for heat shifted little across UHI decile groups, again suggesting acclimatization. For cold, the splines shifted somewhat in the direction of no acclimatization, but did not exclude acclimatization. We have proposed two analytical methods for estimating the degree of acclimatization to the heat- and cold-related mortality burdens associated with UHIs. The results for London suggest relatively complete acclimatization to the UHI effect on summer heat-related mortality, but less clear evidence for cold-related mortality. Milojevic A, Armstrong BG, Gasparrini A, Bohnenstengel SI, Barratt B, Wilkinson P. 2016. Methods to estimate acclimatization to urban heat island effects on heat- and cold-related mortality. Environ Health Perspect 124:1016-1022; http://dx.doi.org/10.1289/ehp.1510109.

Postharvest behaviour of five Sardinian prune varieties as affected by immersion in heated sodium bicarbonate solution.

PubMed

Molinu, M G; Venditti, T; Dore, A; Agabbio, M; Rosas, G; D'Hallewin, G

2010-01-01

Storage behaviour of 'Core', 'Core Columbu', 'Fradis' and 'Meloni' white prunes, and a black one ('Sighera') of Sardinian germplasm were evaluated following immersion for 0 (control), 15, 30, 45 or 60 sec in water at 20, 50, 55 or 60 degrees C with or without 2% (w/v) NaHCO3 (SBC). As international varieties, fruit from one white plum ('Shiro') and one black prune ('Stanly') were subjected to the same treatments. Fruit was harvested at commercial maturity, treated and then stored for 1 month at 5 degrees C and 90% RH followed by a simulated marketing period at 20 degrees C and 80% RH for 6 days. Fruit appearance, external damage, firmness and decay percentage were monitored after storage and SMP. Treatments did not induce rind damage (browning or discoloration) to any variety. SBC at 20, 45, 50 or 55 degrees C for 15 or 30 sec was not effective in controlling decay and compared to controls no improvement was observed. Immersion for 45 or 60 sec with SBC at all temperatures improved decay control with respect to controls and best results were obtained at 50 or 55 degrees C. Immersions at 60 degrees C improved decay control, but differences were not significant compared to the control attained with solutions of SBC heated at 55 degrees C. The overall appearance of 'Core', 'Core Columbu', 'Fradis' and 'Shiro' decreased significantly after the SMP period, especially when treated at 55 or 60 degrees C for 60 sec. Fruit shrivel was the main cause of the low rating. SBC did not affect shrivel indicating that heat treatment may be the probable cause. In general, local varieties were less affected by decay than other varieties and they performed well during storage.

Predicting heat stress index in Sasso hens using automatic linear modeling and artificial neural network

NASA Astrophysics Data System (ADS)

Yakubu, A.; Oluremi, O. I. A.; Ekpo, E. I.

2018-03-01

There is an increasing use of robust analytical algorithms in the prediction of heat stress. The present investigation therefore, was carried out to forecast heat stress index (HSI) in Sasso laying hens. One hundred and sixty seven records on the thermo-physiological parameters of the birds were utilized. They were reared on deep litter and battery cage systems. Data were collected when the birds were 42- and 52-week of age. The independent variables fitted were housing system, age of birds, rectal temperature (RT), pulse rate (PR), and respiratory rate (RR). The response variable was HSI. Data were analyzed using automatic linear modeling (ALM) and artificial neural network (ANN) procedures. The ALM model building method involved Forward Stepwise using the F Statistic criterion. As regards ANN, multilayer perceptron (MLP) with back-propagation network was used. The ANN network was trained with 90% of the data set while 10% were dedicated to testing for model validation. RR and PR were the two parameters of utmost importance in the prediction of HSI. However, the fractional importance of RR was higher than that of PR in both ALM (0.947 versus 0.053) and ANN (0.677 versus 0.274) models. The two models also predicted HSI effectively with high degree of accuracy [r = 0.980, R 2 = 0.961, adjusted R 2 = 0.961, and RMSE = 0.05168 (ALM); r = 0.983, R 2 = 0.966; adjusted R 2 = 0.966, and RMSE = 0.04806 (ANN)]. The present information may be exploited in the development of a heat stress chart based largely on RR. This may aid detection of thermal discomfort in a poultry house under tropical and subtropical conditions.

Predicting heat stress index in Sasso hens using automatic linear modeling and artificial neural network.

PubMed

Yakubu, A; Oluremi, O I A; Ekpo, E I

2018-03-17

There is an increasing use of robust analytical algorithms in the prediction of heat stress. The present investigation therefore, was carried out to forecast heat stress index (HSI) in Sasso laying hens. One hundred and sixty seven records on the thermo-physiological parameters of the birds were utilized. They were reared on deep litter and battery cage systems. Data were collected when the birds were 42- and 52-week of age. The independent variables fitted were housing system, age of birds, rectal temperature (RT), pulse rate (PR), and respiratory rate (RR). The response variable was HSI. Data were analyzed using automatic linear modeling (ALM) and artificial neural network (ANN) procedures. The ALM model building method involved Forward Stepwise using the F Statistic criterion. As regards ANN, multilayer perceptron (MLP) with back-propagation network was used. The ANN network was trained with 90% of the data set while 10% were dedicated to testing for model validation. RR and PR were the two parameters of utmost importance in the prediction of HSI. However, the fractional importance of RR was higher than that of PR in both ALM (0.947 versus 0.053) and ANN (0.677 versus 0.274) models. The two models also predicted HSI effectively with high degree of accuracy [r = 0.980, R 2  = 0.961, adjusted R 2  = 0.961, and RMSE = 0.05168 (ALM); r = 0.983, R 2  = 0.966; adjusted R 2  = 0.966, and RMSE = 0.04806 (ANN)]. The present information may be exploited in the development of a heat stress chart based largely on RR. This may aid detection of thermal discomfort in a poultry house under tropical and subtropical conditions.

Incidence and Predictors of Anal Incontinence After Obstetric Anal Sphincter Injury in Primiparous Women.

PubMed

Richter, Holly E; Nager, Charles W; Burgio, Kathryn L; Whitworth, Ryan; Weidner, Alison C; Schaffer, Joseph; Zyczynski, Halina M; Norton, Peggy; Jelovsek, John Eric; Meikle, Susan F; Spino, Cathie; Gantz, Marie; Graziano, Scott; Brubaker, Linda

2015-01-01

This study aimed to describe the incidence of fecal incontinence (FI) at 6, 12, and 24 weeks postpartum; anal incontinence (AI) and fecal urgency at 24 weeks; and identify predictors of AI in women with obstetric anal sphincter injury (OASI). Primiparous women sustaining OASIs were identified at 8 clinical sites. Third-degree OASIs were characterized using World Health Organization criteria, 3a (<50%) or 3b (>50%) tear through the sphincter. Fecal incontinence was defined as leakage of liquid/solid stool and/or mucus in the past month; AI was defined as leakage of liquid/solid stool and/or mucus and/or gas in the past month and was assessed at 6, 12, and 24 weeks postpartum using the Fecal Incontinence Severity Index. Logistic regression identified variables associated with AI. Three hundred forty-three women participated: 297 subjects sustained a third-degree OASI, 168 type 3a, 98 type 3b and 31 indeterminant; 45 had a fourth-degree OASI. Overall FI incidence at 6, 12, and 24 weeks was 7% [23/326; 95% confidence interval (CI), 4%-10%], 4% (6/145; 95% CI, 2%-9%), and 9% (13/138; 95% CI, 5%-16%), respectively. At 24 weeks, AI incidence was 24% (95% CI, 17%-32%) and fecal urgency 21% (95% CI, 15%-29%). No significant differences in FI and AI rates were noted by third-degree type or between groups with third and fourth OASI. Flatal incontinence was greater in women sustaining a fourth-degree tear (35% vs 16%, P = 0.04). White race (adjusted odds ratio, 4.64; 95% CI, 1.35-16.02) and shorter duration of second stage (adjusted odds ratio, 1.47 per 30 minute decrease; 95% CI, 1.12-1.92) were associated with AI at 24 weeks. Overall 24-week incidence of FI is 9% (95% CI, 5%-16%) and AI is 24% (95% CI, 17%-32%). In women with OASI, white race and shorter second-stage labor were associated with postpartum AI. NCT01166399 (http://clinicaltrials.gov).

Cooling the Origins Space Telescope

NASA Technical Reports Server (NTRS)

Dipirro, M.; Canavan, E.; Fantano, L.

2017-01-01

The NASA Astrophysics Division has commissioned 4 studies for consideration by the 2020 Decadal Survey to be the next flagship mission following WFIRST (Wide Field Infrared Survey Telescope). One of the four studies is the Origins Space Telescope (OST), which will cover wavelengths from 6 microns to 600 microns. To perform at the level of the zodiacal, galactic, and cosmic background, the telescope must be cooled to 4 degrees Kelvin. 4 degrees Kelvin multi-stage mechanical cryocoolers will be employed along with a multilayer sunshield/thermal shield to achieve this temperature with a manageable parasitic heat load. Current state-of-the-art cryocoolers can achieve close to 4 degrees Kelvin, providing about 50 megawatts of cooling at 4 degrees Kelvin with an input power of 500 watts. Multiple coolers at this power level will be used in parallel. These coolers also provide extra cooling power at intermediate temperature stages of 15-20 degrees Kelvin and 50-70 degrees Kelvin . This upper stage cooling will be used to limit the heat conducted to 4 degrees Kelvin . The multi-layer sunshield will limit the radiated thermal energy to the 4 degrees Kelvin volume. This paper will describe the architecture of the cryogenic system for OST along with preliminary thermal models.

Fate of TCE in heated Fort Lewis soil.

PubMed

Costanza, Jed; Fletcher, Kelly E; Löffler, Frank E; Pennell, Kurt D

2009-02-01

This study explores the transformation of trichloroethene (TCE) caused by heating contaminated soil and groundwater samples obtained from the East Gate Disposal Yard (EGDY) located in Fort Lewis, WA. After field samples transferring into glass ampules and introducing 1.5 micromol of TCE, the sealed ampules were incubated at temperatures of 25, 50, and 95 degrees C for periods of up to 95.5 days. Although TCE was completely transformed into cis-1,2-dichloroethene (cis-DCE) after 42 days at 25 degrees C by microbial activity, this transformation was not observed at 50 or 95 degrees C. Chloride levels increased after 42 days at 25 degrees C corresponding to the mass of TCE transformed to cis-DCE, were constant at 50 degrees C, and increased at 95 degrees C yielding a TCE degradation half-life of 1.6-1.9 years. These findings indicate that indigenous microbes contribute to the partial dechlorination of TCE to cis-DCE at temperatures of less than 50 degrees C, whereas interphase mass transfer and physical recovery of TCE will predominate over in situ degradation processes at temperatures of greater than 50 degrees C during thermal treatment at the EGDY site.

The evaporative drying of sludge by immersion in hot oil: Effects of oil type and temperature.

PubMed

Ohm, Tae-In; Chae, Jong-Seong; Lim, Kwang-Soo; Moon, Seung-Hyun

2010-06-15

We investigated the evaporative drying by immersion in hot oil (EDIHO) method for drying sludge. This involved heating oil to a temperature higher than that needed for moisture to be evaporated from the sludge by turbulent heat and mass transfer. We fry-dried sewage and leather plant sludge for 10 min in each of four different oils (waste engine, waste cooking, refined waste, and B-C heavy) and three different temperatures (140 degrees C, 150 degrees C, and 160 degrees C). Drying efficiency was found to be greater for higher temperatures. However, giving consideration to energy efficiency we suggest that the optimal temperature for fry-drying sludge is 150 degrees C. At 150 degrees C, the water content of sewage sludge reduced from 78.9% to between 1.5% (with waste cooking oil) and 3.8% (with waste engine oil). The reduction in water content for leather plant sludge fry-dried at 150 degrees C was from 81.6% to between 1% (with waste cooking oil) and 6.5% (with refined waste oil). The duration of the constant rate-drying period was also influenced by the type of oil used: refined waste oil>waste engine oil>B-C heavy oil>waste cooking oil. The duration at 150 degrees C with waste cooking oil was 3 min for sewage sludge and 2 min for leather plant sludge. It is likely that the drying characteristics of oil are influenced by its thermal properties, including its specific heat, and molecular weight. Copyright 2010 Elsevier B.V. All rights reserved.

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

Pern, F.J.; Czanderna, A.W.

Yellow-browning of the ethylene-vinyl acetate (EVA) copolymer encapsulant used in PV modules has resulted in significant power losses of over 50% of the initial power output. The weathering-degraded yellow-brown EVA films have lost the ultraviolet (UV) absorber, Cyasorb UV 531[sup (R)], and the degree of cross-linking (gel content) has increased. EVA degradation mechanisms identified thus far are discussed in this work. Upon exposure to UV light at 45[degree]--85 [degree]C, virgin EVA films that are stabilized with Cyasorb UV 531[sup (R)] and two antioxidants show an increase in the gel content, a gradual loss of Cyasorb by photooxidation, and the generationmore » of acetic acid. The deacetylation reaction, which leads to the formation of polyenes, also occurs significantly in the films heated in the dark at 130 [degree]C for five days. Acetic acid thermally catalyzes the EVA film discoloration at 85[degree]--130 [degree]C, which increases from a light yellow to a yellow-brown color as the heating temperature increases. The factors can account for the yellow-browning of the EVA in the accelerated testing of mini-modules, and the discoloration is more profound when exposed to UV light at 85 [degree]C than when heated in the dark at the same temperature. In the presence of the EVA-produced acetic acid, oxygen, and sunlight exposure, the Cu buslines that were coated with a thin layer of Pb-Sn alloy showed significant oxidation and metal interdiffusion, which in turn may contribute to the resistance increase and hence the current loss reported for weathered PV modules.« less

[Acceleration of osmotic dehydration process through ohmic heating of foods: raspberries (Rubus idaeus)].

PubMed

Simpson, Ricardo R; Jiménez, Maite P; Carevic, Erica G; Grancelli, Romina M

2007-06-01

Raspberries (Rubus idaeus) were osmotically dehydrated by applying a conventional method under the supposition of a homogeneous solution, all in a 62% glucose solution at 50 degrees C. Raspberries (Rubus idaeus) were also osmotically dehydrated by using ohmic heating in a 57% glucose solution at a variable voltage (to maintain temperature between 40 and 50 degrees C) and an electric field intensity <100 V/cm. When comparing the results from both experiments it was evident that processing time is reduced when ohmic heating technique was used. In some cases this reduction reached even 50%. This is explained by the additional effect to the thermal damage that is generated in an ohmic process, denominated electroporation.

Non-precious metal catalysts prepared from precursor comprising cyanamide

DOEpatents

Chung, Hoon Taek; Zelenay, Piotr

2015-10-27

Catalyst comprising graphitic carbon and methods of making thereof; said graphitic carbon comprising a metal species, a nitrogen-containing species and a sulfur containing species. A catalyst for oxygen reduction reaction for an alkaline fuel cell was prepared by heating a mixture of cyanamide, carbon black, and a salt selected from an iron sulfate salt and an iron acetate salt at a temperature of from about 700.degree. C. to about 1100.degree. C. under an inert atmosphere. Afterward, the mixture was treated with sulfuric acid at elevated temperature to remove acid soluble components, and the resultant mixture was heated again under an inert atmosphere at the same temperature as the first heat treatment step.

Waste heat driven absorption refrigeration process and system

DOEpatents

Wilkinson, William H.

1982-01-01

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

NREL Solar Researcher Honored with ASES Abbot Award | News | NREL

Science.gov Websites

desiccant cooling test laboratory, producing NREL's solar industrial process heat design handbook , developing stretched-membrane parabolic dish solar concentrators, inventing a high-performance heat exchanger the sun's heat to warm the building ventilation air. Kutscher has a B.S. degree in physics from the

Twin solution calorimeter determines heats of formation of alloys at high temperatures

NASA Technical Reports Server (NTRS)

Darby, J. B., Jr.; Kleb, R.; Kleppa, O. J.

1968-01-01

Calvert-type, twin liquid metal solution calorimeter determines the heats of formation of transition metal alloys at high temperatures. The twin differential calorimeter measures the small heat effects generated over extended periods of time, has maximum operating temperature of 1073 degrees K and an automatic data recording system.

Effect of pH on subunit association and heat protection of soybean alpha-galactosidase

NASA Technical Reports Server (NTRS)

Porter, J. E.; Sarikaya, A.; Herrmann, K. M.; Ladisch, M. R.; Mitchell, C. A. (Principal Investigator)

1992-01-01

Soybeans contain the enzyme alpha-galactosidase, which hydrolyzes alpha-1, 6 linkages in stachyose and raffinose to give sucrose and galactose. We have found that galactose, a competitive product inhibitor of alpha-galactosidase, strongly promotes the heat stability of the tetrameric form of the enzyme at pH 4.0 and at temperatures of up to 70 degrees C for 60 min. Stachyose and raffinose also protect alpha-galactosidase from denaturation at pH 4.0 although to a lesser extent. Glucose and mannose have little effect. At pH 7.0 the enzyme is a monomer, and galactose has no effect on the heat stability of the enzyme. In the absence of heat protection of the enzyme by added sugars, a series deactivation mechanism was found to describe the deactivation data. In comparison, a unimolecular, non-first order deactivation model applies at pH 4.0, where heat protection effects were observed. At a temperature above 60 degrees C, simple deactivation is a suitable model. The results suggest that alpha-galactosidase conformation and heat stability are directly related.

Processes for preparing carbon fibers using sulfur trioxide in a halogenated solvent

DOEpatents

Patton, Jasson T.; Barton, Bryan E.; Bernius, Mark T.; Chen, Xiaoyun; Hukkanen, Eric J.; Rhoton, Christina A.; Lysenko, Zenon

2015-12-29

Disclosed here are processes for preparing carbonized polymers (preferably carbon fibers), comprising sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 dissolved in a solvent to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of the solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C. Carbon fibers made according to these methods are also disclosed herein.

Metal glass vacuum tube solar collectors are approaching lower-medium temperature heat application.

PubMed

Jiang, Xinian

2010-04-26

Solar thermal collectors are widely used worldwide mainly for hot water preparation at a low temperature (less than 80?C). Applications including many industrial processes and central air conditioning with absorption chillers, instead require lower-medium temperature heat (between 90 degrees C and 150 degrees C) to be driven when using solar thermal energy. The metal absorber glass vacuum tube collectors (MGVT) are developed for this type of applications. Current state-of-art and possible future technology development of MGVT are presented.

Moist-Heat Resistance, Spore Aging, and Superdormancy in Clostridium difficile▿†

PubMed Central

Rodriguez-Palacios, Alexander; LeJeune, Jeffrey T.

2011-01-01

Clostridium difficile spores can survive extended heating at 71°C (160°F), a minimum temperature commonly recommended for adequate cooking of meats. To determine the extent to which higher temperatures would be more effective at killing C. difficile, we quantified (D values) the effect of moist heat at 85°C (145°F, for 0 to 30 min) on C. difficile spores and compared it to the effects at 71 and 63°C. Fresh (1-week-old) and aged (≥20-week-old) C. difficile spores from food and food animals were tested in multiple experiments. Heating at 85°C markedly reduced spore recovery in all experiments (5 to 6 log10 within 15 min of heating; P < 0.001), regardless of spore age. In ground beef, the inhibitory effect of 85°C was also reproducible (P < 0.001), but heating at 96°C reduced 6 log10 within 1 to 2 min. Mechanistically, optical density and enumeration experiments indicated that 85°C inhibits cell division but not germination, but the inhibitory effect was reversible in some spores. Heating at 63°C reduced counts for fresh spores (1 log10, 30 min; P < 0.04) but increased counts of 20-week-old spores by 30% (15 min; P < 0.02), indicating that sublethal heat treatment reactivates superdormant spores. Superdormancy is an increasingly recognized characteristic in Bacillus spp., and it is likely to occur in C. difficile as spores age. The potential for reactivation of (super)dormant spores with sublethal temperatures may be a food safety concern, but it also has potential diagnostic value. Ensuring that food is heated to >85°C would be a simple and important intervention to reduce the risk of inadvertent ingestion of C. difficile spores. PMID:21398481

Method of making high strength, tough alloy steel

DOEpatents

Thomas, Gareth; Rao, Bangaru V. N.

1979-01-01

A high strength, tough alloy steel, particularly suitable for the mining industry, is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other subsitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

Supplemental heating of deposition tooling shields

DOEpatents

Ohlhausen, James A.; Peebles, Diane E.; Hunter, John A.; Eckelmeyer, Kenneth H.

2000-01-01

A method of reducing particle generation from the thin coating deposited on the internal surfaces of a deposition chamber which undergoes temperature variation greater than 100.degree. C. comprising maintaining the temperature variation of the internal surfaces low enough during the process cycle to keep thermal expansion stresses between the coating and the surfaces under 500 MPa. For titanium nitride deposited on stainless steel, this means keeping temperature variations under approximately 70.degree. C. in a chamber that may be heated to over 350.degree. C. during a typical processing operation. Preferably, a supplemental heater is mounted behind the upper shield and controlled by a temperature sensitive element which provides feedback control based on the temperature of the upper shield.

[Determination of alpha-gliadin content in gluten-containing and gluten-free heated food].

PubMed

Meier, P; Windemann, H; Baumgartner, E

1984-05-01

The amount of alpha-gliadin and whole gliadin in bread dough after heating at temperatures of 50-100 degrees C was determined by ELISA. At temperatures above 80 degrees C the amount which could be found was greatly reduced. In pasta foods containing wheat (with a max. drying temperature of 75 degrees C) alpha-gliadin could be determined totally but in wheat bread (crust and crumb) only 0.5-40% of the content in the original flour was found. The results of an analysis of "gluten-free" pasta foods on the market and the amounts of alpha-gliadin found are discussed in relation to the recommendations of the Codex alimentarius (WHO).

Oil-flow study of a Space Shuttle orbiter tip-fin controller

NASA Technical Reports Server (NTRS)

Helms, V. T., III

1983-01-01

Possible use of tip-fin controllers instead of a vertical tail on advanced winged entry vehicles was examined. Elimination of the vertical tail and using tip-fins offers the advantages of positive yaw control at high angles of attack and a potential weight savings. Oil-flow technique was used to obtain surface flow patterns on a tip-fin installed on a 0.01-scale Space Shuttle orbiter model for the purpose of assessing the extent of flow interference effects on the wing and tip-fin which might lead to serious heating problems. Tests were conducted in air at Mach 10 for a free-stream Reynolds numbers of .000113 at 20, 30, and 40 degree angle of attack and sideslip angles of 0 and 2 degree. Elevon deflections of -10, 0, and 10 degree and tip-fin control-surface deflections of 0, 20, and 40 degree were employed. Test results were also used to aid in the interpretation of heating data obtained on a Shuttle orbiter tip-fin on another model in a different facility. A limited comparison of oil-flow patterns and heat-transfer data is included. It was determined that elevon deflection angles from -10 to 10 degree and sideslip angles up to 2 degree have very little effect on tip-fin surface flow patterns. Also, there is a minimum of interference between the tip-fin and the wing. The most significant flow interactions occur on the tip-fin onboard surface as a result of its control-surface deflections.

Range Extension Opportunities While Heating a Battery Electric Vehicle

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

Lustbader, Jason A; Rugh, John P; Titov, Eugene V

The Kia Soul battery electric vehicle (BEV) is available with either a positive temperature coefficient (PTC) heater or an R134a heat pump (HP) with PTC heater combination (1). The HP uses both ambient air and waste heat from the motor, inverter, and on-board-charger (OBC) for its heat source. Hanon Systems, Hyundai America Technical Center, Inc. (HATCI) and the National Renewable Energy Laboratory jointly, with financial support from the U.S. Department of Energy, developed and proved-out technologies that extend the driving range of a Kia Soul BEV while maintaining thermal comfort in cold climates. Improved system configuration concepts that use thermalmore » storage and waste heat more effectively were developed and evaluated. Range extensions of 5%-22% at ambient temperatures ranging from 5 degrees C to -18 degrees C were demonstrated. This paper reviews the three-year effort, including test data of the baseline and modified vehicles, resulting range extension, and recommendations for future actions.« less

Thermal inactivation kinetics of Salmonella spp. within intact eggs heated using humidity-controlled air.

PubMed

Brackett, R E; Schuman, J D; Ball, H R; Scouten, A J

2001-07-01

The heat resistance of six strains of Salmonella (including Enteritidis, Heidelberg, and Typhimurium) in liquid whole egg and shell eggs was determined. Decimal reduction times (D-values) of each of the six strains were determined in liquid whole egg heated at 56.7 degrees C within glass capillary tubes immersed in a water bath. D-values ranged from 3.05 to 4.09 min, and significant differences were observed between the strains tested (alpha = 0.05). In addition, approximately 7 log10 CFU/g of a six-strain cocktail was inoculated into the geometric center of raw shell eggs and the eggs heated at 57.2 degrees C using convection currents of humidity-controlled air. D-values of the pooled salmonellae ranged from 5.49 to 6.12 min within the center of intact shell eggs. A heating period of 70 min or more resulted in no surviving salmonellae being detected (i.e., an 8.7-log reduction per egg).

Heat loss from giant extinct reptiles.

PubMed

Ruxton, G D

2001-09-22

There is disagreement in the literature about the relative rates of heat loss from a large animal surrounded by either air or water. Here, it is shown that, in most circumstances, the rate at which heat is lost by a large body is significantly greater when it is immersed in water than when it is surrounded by air, assuming that the two fluids are at the same temperature. The only circumstance when this may not apply is when comparing air with fresh water when both are at a temperature somewhere between 0 degrees C and 6 degrees C, the animal is still and water or air currents are negligible. Under these conditions, free convection in water is weak or non-existent, and so the combined effect of conduction and free convection in air becomes comparable to or even greater than that of conduction alone in water. However, in these circumstances, radiation is the dominant mode of heat loss to both media, and so heat losses are approximately the same in both air and water.

[Variables effecting casting accuracy of quick heating casting investments].

PubMed

Takahashi, H; Nakamura, H; Iwasaki, N; Morita, N; Habu, N; Nishimura, F

1994-06-01

Recently, several new products of investments for "quick heating" have been put on the Japanese market. The total casting procedure time for this quick heating method involves only one hour; 30-minutes waiting after the start of mixing before placing the mold directly into the 700 degrees C furnace and 30-minutes heating in the furnace. The purpose of this study was to evaluate two variables effecting casting accuracy using these new investments. The effect of thickness of the casting liner inside the casting ring and the effect of waiting time before placing the mold into the 700 degrees C furnace were evaluated. A stainless-steel die with a convergence angle of 8 degrees was employed. Marginal discrepancies of the crown between the wax patterns and castings were measured. The size of the cast crown became larger when the thickness of the ring liner was thick and when the waiting time before placing the mold into the furnace was long. These results suggest that these new investments have the advantage of providing sound castings using short-time casting procedures. However, it is necessary to pay careful attention to the casting conditions for obtaining reproducible castings.

Heating Rate Distributions at Mach 10 on a Circular Body Earth-to-Orbit Transport Vehicle

NASA Technical Reports Server (NTRS)

Wells, William L.; MacConochie, Ian O.; Helms, Vernon T., III; Raney, David

1985-01-01

Among the concepts being considered for future Earth-to-orbit transport vehicles are fully reusable single-stage systems which take off vertically and land horizontally. Because these vehicles carry their own propellant internally, they are much larger than the present Space Shuttle Orbiter. One such single-stage vehicle under study is the circular body configuration which has the advantages of simple structural design and large volume-to-weight ratio. As part of an overall evaluation of this configuration, a series of heat transfer and surface flow tests were conducted. The phase-change paint and oil-flow tests were performed in the Langley 31-Inch Mach-10 Tunnel at angles of attack from 20 through 40 degrees in 5-degree increments. Heat-transfer coefficient data are presented for all angles of attack and detailed oil-flow photographs are shown for windward and leeward surfaces at 25 and 40 degrees angle of attack. In many ways, heating was similar to that previously determined for the Shuttle Orbiter so that, in a cursory sense, existing thermal protection systems would appear to be adequate for the proposed circular-body configurations.

Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

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

Gandy, J.H.; Pruden, E.L.; Cox, F.R.

1983-12-01

Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth indexmore » (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units.« less

The role of prostaglandins and the hypothalamus in thermoregulation in the lizard, Phrynocephalus przewalskii (Agamidae).

PubMed

Liu, Chongbin; Li, Rende; Liu, Zhonghu; Yin, Shuming; Wang, Ziren

2006-05-01

Typically, small lizards rely heavily on behavioral thermoregulation rather than physiological mechanisms to control their rates of warming and cooling. We tested the hypothesis that prostaglandins participate in mediating the cardiovascular response to heating and cooling and temperature regulating neurons in the hypothalamus of the small lizard Phrynocephalus przewalskii. In vivo and in vitro treatments, heart rates (HRs) were all found to be higher during heating than during cooling, hysteresis was distinct below 30 and 26 degrees Celsius, respectively. In vivo, as administration of COX inhibitor, there were no differences in HR between heating and cooling at any body temperature and administration of agonist prostaglandins only produced a significant effect on HR below 25 degrees Celsius. Single-unit activity was recorded extracellularly in vitro with microelectrodes, found the firing rate of the continuous unit increased 23% when the temperature of the artificial cerebrospinal fluid dropped from 30-20 degrees Celsius. We conclude that prostaglandins appear to play only a limited role in modulating heart activity in Phrynocephalus przewalskii and suggest that cold-sensitive neurons in the preoptic and anterior hypothalamus (PO/AH) are involved in thermoregulatory control during heating or cooling.

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

PubMed

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

2007-06-01

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

The effects of heat treatment on selected properties of a conventional and a resin-modified glass ionomer cement.

PubMed

Rafeek, Reisha N

2008-05-01

This study investigated the effects of application of heat alone and heat & pressure on the compressive strength and modulus, the stress relaxation characteristics and the fluoride release of a conventional and a resin-modified glass ionomer cement. Cylindrical specimens were made from both materials and divided into 3 groups. One group was heat treated in an oven at 120 degrees C for 20 min, another group was subjected to heat & pressure at 120 degrees C for 20 min at 6-bar pressure. The third group acted as a control. The compressive strength and modulus, stress relaxation and fluoride release were tested over 56 days. The results of this investigation indicate that heat treatment had no significant effect on the conventional GIC used but significantly affected the resin modified GIC by increasing both the compressive strength and modulus and reducing the stress relaxation characteristics and the fluoride release. The use of GIC to produce inlay or onlay restorations that adhere to tooth tissue and release fluoride would be highly desirable. The results of this study indicate that it is possible to improve the strength of RMGIC with heat to a limited extent, but fluoride release may decrease.

Silicon carbide passive heating elements in microwave-assisted organic synthesis.

PubMed

Kremsner, Jennifer M; Kappe, C Oliver

2006-06-09

Microwave-assisted organic synthesis in nonpolar solvents is investigated utilizing cylinders of sintered silicon carbide (SiC)--a chemically inert and strongly microwave absorbing material--as passive heating elements (PHEs). These heating inserts absorb microwave energy and subsequently transfer the generated thermal energy via conduction phenomena to the reaction mixture. The use of passive heating elements allows otherwise microwave transparent or poorly absorbing solvents such as hexane, carbon tetrachloride, tetrahydrofuran, dioxane, or toluene to be effectively heated to temperatures far above their boiling points (200-250 degrees C) under sealed vessel microwave conditions. This opens up the possibility to perform microwave synthesis in unpolar solvent environments as demonstrated successfully for several organic transformations, such as Claisen rearrangements, Diels-Alder reactions, Michael additions, N-alkylations, and Dimroth rearrangements. This noninvasive technique is a particularly valuable tool in cases where other options to increase the microwave absorbance of the reaction medium, such as the addition of ionic liquids as heating aids, are not feasible due to an incompatibility of the ionic liquid with a particular substrate. The SiC heating elements are thermally and chemically resistant to 1500 degrees C and compatible with any solvent or reagent.

Thermal death kinetics of fifth-instar Plodia interpunctella (Lepidoptera: Pyralidae).

PubMed

Johnson, J A; Wang, S; Tang, J

2003-04-01

Heat treatments have been suggested as alternatives to chemical fumigants for control of postharvest insects in dried fruits and nuts. Conventional forced hot air treatments heat product too slowly to be practical, but radio frequency treatments are capable of more rapid product heating. While developing radio frequency heat treatments for dried fruits and nuts, the heat tolerance of nondiapausing and diapausing fifth-instar larvae of the Indianmeal moth, Plodia interpunctella (Hübner), was determined using a heating block system developed by Washington State University. Both a 0.5th order kinetic model and a classical empirical model were used to estimate lethal exposure times for temperatures of 44-52 degrees C for nondiapausing fifth-instar larvae. We obtained 95% mortality at exposures suitable for practical radio frequency treatments (< or = 5 min) with temperatures of 50 and 52 degrees C. Diapausing larvae were significantly more tolerant than nondiapausing larvae at the lowest treatment temperature and shortest exposure, but differences were not significant at more extreme temperature-time combinations. Previous studies showed that fifth-instar larvae of the navel orangeworm, Amyelois transitella (Walker), were more heat tolerant than either diapausing or nondiapausing Indianmeal moth larvae. Consequently, efficacious treatments for navel orangeworm would also control Indianmeal moth.

Characterization of an extemporaneous liquid formulation of lisinopril.

PubMed

Thompson, Karen C; Zhao, Zhongxi; Mazakas, Jessica M; Beasley, Christopher A; Reed, Robert A; Moser, Cheryl L

2003-01-01

The stability of lisinopril in an extemporaneously prepared suspension stored at or below 25 degrees C for 28 days under ambient light exposure was studied. A formulation of 1-mg/mL oral suspension was prepared from commercially available 20-mg lisinopril tablets, using Bicitra and Ora-Sweet SF as the compounding vehicles to make a final volume of 200 mL. Individual samples, stored in 8-oz amber polyethylene terephthalate bottles, were used for each test performed. All samples were stored at 25 degrees C. Appropriateness of the extemporaneous preparation method was performed by shaking three lots of each suspension for 30, 60, and 90 seconds. To test the robustness and reproducibility of the method, two chemists prepared the suspensions from the same three lots of lisinopril tablets. Chemical and physical stability were established by analyzing duplicate samples at time zero and after one, two, four, and six weeks. The solubility of lisinopril was tested from suspensions stored for four weeks. In-use stability was also examined over four weeks. Photochemical stability was examined by exposing three batches of the suspension to maximum light stress in accordance with the International Conference on Harmonization. Antimicrobial-effectiveness testing was also conducted with freshly prepared suspensions and suspensions stored for six weeks. The preparation method used was appropriate and effective. Lisinopril is fully dissolved in the suspension matrix. Satisfactory chemical, physical, and microbiological results were obtained after the suspensions were stored for six weeks at 25 degrees C and 35% relative humidity. Lisinopril suspensions extemporaneously prepared from tablets are stable for at least four weeks when stored at or below 25 degrees C under ambient light exposure.

Metabolism and evaporative heat loss in the dik-dik antelope (Rhynchotragus kirki).

PubMed

Kamau, J M

1988-01-01

1. Under controlled conditions, the rate of oxygen consumption (VO2) respiratory frequency, evaporative water loss, heat balance, rectal (Trec) and surface temperatures were determined in the dik-dik antelopes at ambient temperatures (Ta) ranging from 1 to 44 degrees C. 2. The thermal neutral zone was found to be between 24 and 35 degrees C. 3. Respiratory frequency ranged between 27 and 630 breaths/min. 4. At a Ta of 44 degrees C, 95% of the heat produced by the dik-dik was lost via respiratory evaporation. Despite an increase in Trec, cutaneous evaporation did not increase. 5. During panting, VO2 increased in accordance with the expected Q10 effect, contrary to earlier findings. 6. Measurements of circadian rhythm [LD 12:12 (7-19) CT26 degrees C] in VO2 showed that the minimum VO2 (0.42 ml O2/g/hr) occurred at midnight while the maximum (0.78 ml O2/g/hr) occurred at midday. The 24 hr mean VO2 was 0.61 ml O2/g/hr. 7. These measurements suggest that in nature, determinants other than light may be responsible for triggering the variations observed in VO2.

Localised heating of tumours utilising injectable magnetic nanoparticles for hyperthermia cancer therapy.

PubMed

Tseng, H-Y; Lee, G-B; Lee, C-Y; Shih, Y-H; Lin, X-Z

2009-06-01

This study reports an investigation of hyperthermia cancer therapy utilising an alternating magnetic field to induce a localised temperature increase on tumours by using injectable magnetic nanoparticles. In-vitro and in-vivo experiments represent the feasibility of hyperthermia cancer therapy. A feedback temperature control system was first developed to keep the nanoparticles at a constant temperature to prevent overheating in the tumours such that a safer and more precise cancer therapy becomes feasible. By using the feedback temperature control system, magnetic nanoparticles can be heated up to the specific constant temperatures, 37, 40, 42, 45, 46 and 47 degrees C, respectively, with a variation less than 0.2 degrees C. With this approach, the in-vitro survival rate of tumour cells at different temperatures can be systematically explored. It was experimentally found that the survival rate of cancer cells can be greatly reduced while CT-26 cancer cells were heated above 45 degrees C. Besides, localised temperatures increase as high as 59.5 degrees C can be successfully generated in rat livers by using the proposed method. Finally, complete regression of tumour was achieved. The developed method used injectable magnetic nanoparticles and may provide a promising approach for hyperthermia cancer therapy.

Temporal changes of ethoxyresorufin-o-deethylase (EROD) activities and lysosome accumulation in intestine of fish on chronic exposure to dietary benzo[a]pyrene: linking erod induction to cytological effects.

PubMed

Yuen, Bonny B H; Au, Doris W T

2006-10-01

Temporal changes of intestinal and hepatic ethoxyresorufin-O-deethylase (EROD) activities and quantitative changes of secondary and tertiary (e.g., 2 degrees/3 degrees) lysosomes in enterocytes were compared for the juvenile grouper (Epinephelus coioides) on chronic exposure to foodborne benzo[a]pyrene (BaP) at two environmentally realistic levels (0.25 and 12.5 microg/g fish/d) over a four-week exposure and four-week depuration period. Intestinal EROD induction was rapid (within 3 d) and sustained in the BaP-exposed fish, while a fast recovery (within one week) was observed on withdrawal of BaP intake. A dose-response relationship was demonstrated between intestinal EROD activities and the levels of foodborne BaP. Conversely, hepatic EROD induction was weak and subsided rapidly in the exposed fish, signifying that hepatic EROD activity is not a good indicator of oral intake of BaP. Significant increase of 2 degrees/3 degrees lysosomes, as measured by Vv(lysosome, mucosa), was detected in young enterocytes of fish in the high-dosing group (12.5 microg/g fish/d) at exposure day 3 and persisted until recovery week 2. Importantly, intestinal EROD activity was significantly correlated to 2 degrees/3 degrees lysosome accumulation in enterocytes (r = 0.571, p < 0.001). These results further corroborate our earlier findings that induction of EROD activities in fish do not merely indicate exposure to BaP but also are correlated to harmful biological effects. We recommend the use of these two biochemical and cytological changes in intestines as specific biomarkers to indicate current and recent exposure of fish to BaP via oral intake.

Subseasonal prediction of the heat wave of December 2013 in Southern South America by the POAMA and BCC-CPS models

NASA Astrophysics Data System (ADS)

Osman, Marisol; Alvarez, Mariano S.

2018-01-01

The prediction skill of subseasonal forecast models is evaluated for a strong and long-lasting heat wave occurred in December 2013 over Southern South America. Reforecasts from two models participating in the WCRP/WWRP Subseasonal to Seasonal project, the Bureau of Meteorology POAMA and Beijing Climate Center model BCC-CPS were considered to evaluate their skill in forecasting temperature and circulation anomalies during that event. The POAMA reforecast of 32-member ensemble size, initialized every five days, and BCC-CPS reforecast of 4-member ensemble size for the same date of POAMA plus the previous 4 days were considered. Weekly ensemble-mean forecasts were computed with leadtimes from 2 days up to 24 days every 5 days. Weekly anomalies were calculated for observations from 13th of December to 31st of December 2013. Anomalies for both observations and reforecast were calculated with respect to their own climatology. Results show that the ensemble mean warm anomalies forecasted for week 1 and 2 of the heat wave resulted more similar to the observations for the POAMA model, especially for longer leads. The BCC-CPS performed better for leads shorter than 7 (14) for week 1 (2). For week 3 the BCC-CPS outperformed the POAMA model, particularly at shorter leads, locating more accurately the maxima of the anomalies. In a probabilistic approach, POAMA predicted with a higher chance than BCC-CPS the excess of the upper tercile of temperature anomalies for almost every week and lead time. The forecast of the circulation anomalies over South America could be used to explain the location of the highest temperature anomalies. In summary, for this case, models skill in forecasting surface temperature in a context of a heat wave resulted moderate at lead times longer than the fortnight. However, this study is limited to model-to-model analysis and a multi-model ensemble strategy might increase the skill.

Cervical external immobilization devices: evaluation of magnetic resonance imaging issues at 3.0 Tesla.

PubMed

Diaz, Francis L; Tweardy, Lisa; Shellock, Frank G

2010-02-15

Laboratory investigation, ex vivo. Currently, no studies have addressed the magnetic resonance imaging (MRI) issues for cervical external immobilization devices at 3-Tesla. Under certain conditions significant heating may occur, resulting in patient burns. Furthermore, artifacts can be substantial and prevent the diagnostic use of MRI. Therefore, the objective of this investigation was to evaluate MRI issues for 4 different cervical external immobilization devices at 3-Tesla. Excessive heating and substantial artifacts are 2 potential complications associated with performing MRI at 3-Tesla in patients with cervical external immobilization devices. Using ex vivo testing techniques, MRI-related heating and artifacts were evaluated for 4 different cervical devices during MRI at 3-Tesla. Four cervical external immobilization devices (Generation 80, Resolve Ring and Superstructure, Resolve Ring and Jerome Vest/Jerome Superstructure, and the V1 Halo System; Ossur Americas, Aliso Viejo, CA) underwent MRI testing at 3-Tesla. All devices were made from nonmetallic or nonmagnetic materials. Heating was determined using a gelled-saline-filled skull phantom with fluoroptic thermometry probes attached to the skull pins. MRI was performed at 3-Tesla, using a high level of RF energy. Artifacts were assessed at 3-Tesla, using standard cervical imaging techniques. The Generation 80 and V1 Halo devices exhibited substantial temperature rises (11.6 degrees C and 8.5 degrees C, respectively), with "sparking" evident for the Generation 80 during the MRI procedure. Artifacts were problematic for these devices, as well. By comparison, the 2 Resolve Ring-based cervical external immobilization devices showed little or no heating (< or = 0.6 degrees C) and the artifacts were acceptable for diagnostic MRI examinations. The low degree of heating and minor artifacts associated with the Resolve-based cervical external immobilization devices indicated that these products are safe for patients undergoing MRI at 3-Tesla.

Program Solicitation Number 86.1, Small Business Innovation Research Program.

DTIC Science & Technology

1986-01-31

Temperature Heat Pipe Technology DESCRIPTION: Heat pipes have been shown to provide superior growth conditions for the growth of bulk semiconductor crystals... Heat pipes allow for the establishment of isothermal conditions over large areas. This thermal property controls the distribution of impurities, and...reliable high temperature heat pipes to operate at 1325 degrees C with inert overpressures of 60 atmospheres is required for the processing of III-V

Small heat-shock proteins and leaf cooling capacity account for the unusual heat tolerance of the central spike leaves in Agave tequilana var. Weber.

PubMed

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

2009-12-01

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

Influence of local noxious heat stimulation on sensory nerve activity in the feline dental pulp.

PubMed

Ahlberg, K F

1978-05-01

The present investigation was undertaken to develop an experimental model in which noxious heat stimulation was used to produce increased intradental sensory nerve activity in canine teeth of anesthetized cats. Two techniques were evaluated in which both the method of recording and the nature of the stimulus varied. Slow heating (approx 1 degree C/s) to 47 degree C of the tooth surface (combined with recording from electrodes in open dentinal cavities) did not produce any persistent nerve activity. Repeated periods of brief intense heating (approx 60 degrees C/s) (combined with recording from amalgam electrodes placed on cavity floors) resulted in an immediate response and an afterdischarge (phase 3) generally persisting for 20--60 min. Maximum phase 3 activity was characteristic for the individual cat and ranged from 0.2 to 50.2 imp/s. mean value 10.6 imp/s (S.D. +/- 9.2). A systematically higher phase 3 activity was recorded in lower compared to upper canine teeth (p less than 0.05). The maximum phase 3 response generally occurred after 3-8 stimulations; the median number of required stimuli was 3. Repeated brief heat stimulations combined with the closed cavity recording technique may be used as an experimental model by which the mechanisms behind increases in intradental sensory nerve activity associated with tissue damage can be studied.

Effect of 900 MHz electromagnetic fields on nonthermal induction of heat-shock proteins in human leukocytes.

PubMed

Lim, Hooi B; Cook, Greg G; Barker, Anthony T; Coulton, Les A

2005-01-01

Despite many studies, the evidence as to whether radiofrequency fields are detrimental to health remains controversial, and the debate continues. Cells respond to some abnormal physiological conditions by producing cytoprotective heat-shock (or stress) proteins. The aim of this study was to determine whether exposure to mobile phone-type radiation causes a nonthermal stress response in human leukocytes. Human peripheral blood was sham-exposed or exposed to 900 MHz fields (continuous-wave or GSM-modulated signal) at three average specific absorption rates (0.4, 2.0 and 3.6 W/kg) for different durations (20 min, 1 h and 4 h) in a calibrated TEM cell placed in an incubator to give well-controlled atmospheric conditions at 37 degrees C and 95% air/5% CO(2). Positive (heat-stressed at 42 degrees C) and negative (kept at 37 degrees C) control groups were incubated simultaneously in the same incubator. Heat caused an increase in the number of cells expressing stress proteins (HSP70, HSP27), measured using flow cytometry, and this increase was dependent on time. However, no statistically significant difference was detected in the number of cells expressing stress proteins after RF-field exposure. These results suggest that mobile phone-type radiation is not a stressor of normal human lymphocytes and monocytes, in contrast to mild heating.

Neonates in Ahmedabad, India, during the 2010 heat wave: a climate change adaptation study.

PubMed

Kakkad, Khyati; Barzaga, Michelle L; Wallenstein, Sylvan; Azhar, Gulrez Shah; Sheffield, Perry E

2014-01-01

Health effects from climate change are an international concern with urban areas at particular risk due to urban heat island effects. The burden of disease on vulnerable populations in non-climate-controlled settings has not been well studied. This study compared neonatal morbidity in a non-air-conditioned hospital during the 2010 heat wave in Ahmedabad to morbidity in the prior and subsequent years. The outcome of interest was neonatal intensive care unit (NICU) admissions for heat. During the months of April, May, and June of 2010, 24 NICU admissions were for heat versus 8 and 4 in 2009 and 2011, respectively. Both the effect of moving the maternity ward and the effect of high temperatures were statistically significant, controlling for each other. Above 42 degrees Celsius, each daily maximum temperature increase of a degree was associated with 43% increase in heat-related admissions (95% CI 9.2-88%). Lower floor location of the maternity ward within hospital which occurred after the 2010 heat wave showed a protective effect. These findings demonstrate the importance of simple surveillance measures in motivating a hospital policy change for climate change adaptation-here relocating one ward-and the potential increasing health burden of heat in non-climate-controlled institutions on vulnerable populations.

Neonates in Ahmedabad, India, during the 2010 Heat Wave: A Climate Change Adaptation Study

PubMed Central

Kakkad, Khyati; Barzaga, Michelle L.; Wallenstein, Sylvan; Sheffield, Perry E.

2014-01-01

Health effects from climate change are an international concern with urban areas at particular risk due to urban heat island effects. The burden of disease on vulnerable populations in non-climate-controlled settings has not been well studied. This study compared neonatal morbidity in a non-air-conditioned hospital during the 2010 heat wave in Ahmedabad to morbidity in the prior and subsequent years. The outcome of interest was neonatal intensive care unit (NICU) admissions for heat. During the months of April, May, and June of 2010, 24 NICU admissions were for heat versus 8 and 4 in 2009 and 2011, respectively. Both the effect of moving the maternity ward and the effect of high temperatures were statistically significant, controlling for each other. Above 42 degrees Celsius, each daily maximum temperature increase of a degree was associated with 43% increase in heat-related admissions (95% CI 9.2–88%). Lower floor location of the maternity ward within hospital which occurred after the 2010 heat wave showed a protective effect. These findings demonstrate the importance of simple surveillance measures in motivating a hospital policy change for climate change adaptation—here relocating one ward—and the potential increasing health burden of heat in non-climate-controlled institutions on vulnerable populations. PMID:24734050

Short term post-partum heat stress in dairy cows

NASA Astrophysics Data System (ADS)

Fuquay, J. W.; Chapin, L. T.; Brown, W. H.

1980-06-01

Since many dairy cows calve during late summer, the objective was to determine if heat stress immediately post-partum would (1) alter metabolism, thus, increasing susceptibility to metabolic disorders, (2) affect lactation and/or (3) affect reproduction. Forty four cows, calving during late summer, were paired with one member of each pair stressed (HS) for the first 10 post-partum days in a hot barn. Controls (CC) were kept in a cooled section of the barn. Plasma drawn weekly for 7 weeks was analyzed in an autoanalyzer for calcium, inor. phosphorus, protein, glucose and cholesterol and by radioimmunoassay for cortisol and progesterone. Ovaries and uteri were palpated weekly. Rectal temperatures were significant higher for HS during the first 10 post-partum days. No significant effects on plasma constituents were observed during the 10-day treatment period. For the 7-week period, glucose and cholesterol were lower in HS, as were cyclic peaks of progesterone and cortisol. Both calcium and inorganic phosphorus remained clinically low for the 7 weeks, but no treatment effects were seen. Uteri of HS involuted more rapidly than the CC. Treatment did not affect reproductive efficiency. Lactation milk yields did not differ, but milk fat percent was lower in HS. Heat stress immediately post-partum altered lipid metabolism, but the animal's compensatory mechanisms prevented reduction in milk production or reproductive efficiency.

Rapid and uniform electromagnetic heating of aqueous cryoprotectant solutions from cryogenic temperatures.

PubMed

Ruggera, P S; Fahy, G M

1990-10-01

Devitrification (ice formation during warming) is one of the primary obstacles to successful organ vitrification (solidification without ice formation). The only feasible approach to overcoming either devitrification or its damaging effects in a large organ appears at present to be the use of some form of electromagnetic heating (EH) to achieve the required high heating rates. One complication of EH in this application is the need for warming within a steel pressure vessel. We have previously reported that resonant radiofrequency (RF) helical coils provide very uniform heating at ambient temperatures and low heating rates and can be modified for coaxial power transmission, which is necessary if only one cable is to penetrate through the wall of the pressure vessel. We now report our initial studies using a modified helical coil, high RF input power, and cryogenic aqueous cryoprotectant solutions [60% (w/v) solution of 4.37 M dimethylsulfoxide and 4.37 M acetamide in water and 50% (w/w) 1,2-propanediol]. We also describe the electronic equipment required for this type of research. Temperatures were monitored during high-power conditions with Luxtron fiberoptic probes. Thermometry was complicated by the use of catheters needed for probe insertion and guidance. The highest heating rates we observed using catheters occurred at temperatures ranging from about -70 to -40 degrees C, the temperature zone where devitrification usually appears in unstable solutions during slow warming. We find that in this range we can achieve measured heating rates of approximately 300 degrees C/min in 30- to 130-ml samples using 200 to 700 W of RF power without overheating the sample at any point. However, energy conservation calculations imply that our measured peak heating rates may be considerably higher than the true heating rates occurring in the bulk of our solutions. We were able to estimate the overall true heating rates, obtaining an average value of about 20 degrees C/min/100 W/100 ml, which implies a heating efficiency close to 100%. It appears that it should be possible to warm vitrified rabbit kidneys rapidly enough under high-pressure conditions to protect them from devitrification.

Influence of the pineal gland and melatonin on blood flow and evaporative water loss during heat stress in rats.

PubMed

Harlow, H J

1987-01-01

Plasma melatonin levels of laboratory rats were elevated both during acute heat exposure (43 degrees C for 40 min) and chronic exposure (33 degrees C for 17 days) suggesting a possible correlation between melatonin and thermoregulatory mechanisms. Pinealectomy reduced the nighttime elevation in oxygen consumption and evaporative water loss. In addition, pinealectomized animals exhibited a significantly lower cutaneous evaporative water loss both at night and during the day when exposed to an acute heat exposure of 38 degrees C for 45 min. Pinealectomy elevated the blood pressure over the control group whereas melatonin infusion depressed the blood pressure without altering the cardiac output. This relationship implies an action by melatonin on the peripheral vasculature. In support of this conclusion, melatonin pretreatment tended to dampen the vasopressive effect of infused norepinephrine. These data, therefore, suggest a role of the pineal gland and melatonin in thermoregulation through an influence on the cardiovascular system and evaporative water loss.

Adsorption of nicotine from aqueous solution onto hydrophobic zeolite type USY

NASA Astrophysics Data System (ADS)

Lazarevic, Natasa; Adnadjevic, Borivoj; Jovanovic, Jelena

2011-07-01

The isothermal adsorption of nicotine from an aqueous solution onto zeolite type USY was investigated. The adsorption isotherms of nicotine onto the zeolite at different temperatures ranging from 298 to 322 K were determined. It was found that the adsorption isotherms can be described by the model of Freundlich adsorption isotherm. Based on the adsorption isotherms the changes of adsorption heat, free energy and entropy with adsorption degree were determined. The determined decrease of adsorption heat with adsorption degree can be explained by the presence of the adsorption centers of different energy and concentration on interface of zeolite-nicotine solution. It was found that the probability function of density distribution of the heat of adsorption (DDF) has exponential form. It was concluded that the possibility of fitting the adsorption isotherms of nicotine onto the zeolite by Freundlich adsorption isotherm was a direct consequence of that. The determined increase in entropy with the increase in adsorption degree can be explained with the change of phase state of adsorbed nicotine.

Experimental investigation of a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine.

PubMed

Luo, E C; Dai, W; Zhang, Y; Ling, H

2006-12-22

In this paper, a thermally-driven thermoacoustic refrigerator system without any moving part is reported. This refrigeration system consists of a thermoacoustic-Stirling heat engine and a thermoacoustic-Stirling refrigerator; that is, the former is the driving source for the latter. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it was found that the DC-flows had significant negative effect on the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems and worked very well. Then extensive experiments were made to test the influence of different parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65 degrees C, a cooling capacity of about 270 W at -20 degrees C and 405 W at 0 degrees C; in fact, the result showed a good prospect of the refrigeration system in room-temperature cooling such as food refrigeration and air-conditioning.

Dual-mode antenna design for microwave heating and noninvasive thermometry of superficial tissue disease.

PubMed

Jacobsen, S; Stauffer, P R; Neuman, D G

2000-11-01

Hyperthermia therapy of superficial skin disease has proven clinically useful, but current heating equipment is somewhat clumsy and technically inadequate for many patients. The present effort describes a dual-purpose, conformal microwave applicator that is fabricated from thin, flexible, multilayer printed circuit board (PCB) material to facilitate heating of surface areas overlaying contoured anatomy. Preliminary studies document the feasibility of combining Archimedean spiral microstrip antennas, located concentrically within the central region of square dual concentric conductor (DCC) annular slot antennas. The motivation is to achieve homogeneous tissue heating simultaneously with noninvasive thermometry by radiometric sensing of blackbody radiation from the target tissue under the applicator. Results demonstrate that the two antennas have complimentary regions of influence. The DCC ring antenna structure produces a peripherally enhanced power deposition pattern with peaks in the outer corners of the aperture and a broad minimum around 50% of maximum centrally. In contrast, the Archimedean spiral radiates (or receives) energy predominantly along the boresight axis of the spiral, thus confining the region of influence to tissue located within the central broad minimum of the DCC pattern. Analysis of the temperature-dependent radiometer signal (brightness temperature) showed linear correlation of radiometer output with test load temperature using either the spiral or DCC structure as the receive antenna. The radiometric performance of the broadband Archimedean antenna was superior compared to the DCC, providing improved temperature resolution (0.1 degree C-0.2 degree C) and signal sensitivity (0.3 degree C-0.8 degree C/degree C) at all four 500 MHz integration bandwidths tested within the frequency range from 1.2 to 3.0 GHz.

Microfabricated thermal modulator for comprehensive two-dimensional micro gas chromatography: design, thermal modeling, and preliminary testing.

PubMed

Kim, Sung-Jin; Reidy, Shaelah M; Block, Bruce P; Wise, Kensall D; Zellers, Edward T; Kurabayashi, Katsuo

2010-07-07

In comprehensive two-dimensional gas chromatography (GC x GC), a modulator is placed at the juncture between two separation columns to focus and re-inject eluting mixture components, thereby enhancing the resolution and the selectivity of analytes. As part of an effort to develop a microGC x microGC prototype, in this report we present the design, fabrication, thermal operation, and initial testing of a two-stage microscale thermal modulator (microTM). The microTM contains two sequential serpentine Pyrex-on-Si microchannels (stages) that cryogenically trap analytes eluting from the first-dimension column and thermally inject them into the second-dimension column in a rapid, programmable manner. For each modulation cycle (typically 5 s for cooling with refrigeration work of 200 J and 100 ms for heating at 10 W), the microTM is kept approximately at -50 degrees C by a solid-state thermoelectric cooling unit placed within a few tens of micrometres of the device, and heated to 250 degrees C at 2800 degrees C s(-1) by integrated resistive microheaters and then cooled back to -50 degrees C at 250 degrees C s(-1). Thermal crosstalk between the two stages is less than 9%. A lumped heat transfer model is used to analyze the device design with respect to the rates of heating and cooling, power dissipation, and inter-stage thermal crosstalk as a function of Pyrex-membrane thickness, air-gap depth, and stage separation distance. Experimental results are in agreement with trends predicted by the model. Preliminary tests using a conventional capillary column interfaced to the microTM demonstrate the capability for enhanced sensitivity and resolution as well as the modulation of a mixture of alkanes.

Heat transfer coefficient: Medivance Arctic Sun Temperature Management System vs. water immersion.

PubMed

English, M J; Hemmerling, T M

2008-07-01

To improve heat transfer, the Medivance Arctic Sun Temperature Management System (Medivance, Inc., Louisville, CO, USA) features an adhesive, water-conditioned, highly conductive hydrogel pad for intimate skin contact. This study measured and compared the heat transfer coefficient (h), i.e. heat transfer efficiency, of this pad (hPAD), in a heated model and in nine volunteers' thighs; and of 10 degrees C water (hWATER) in 33 head-out immersions by 11 volunteers. Volunteer studies had ethical approval and written informed consent. Calibrated heat flux transducers measured heat flux (W m-2). Temperature gradient (DeltaT) was measured between skin and pad or water temperatures. Temperature gradient was changed through the pad's water temperature controller or by skin cooling on immersion. The heat transfer coefficient is the slope of W m-2/DeltaT: its unit is W m-2 degrees C-1. Average with (95% CI) was: model, hPAD = 110.4 (107.8-113.1), R2 = 0.99, n = 45; volunteers, hPAD = 109.8 (95.5-124.1), R2 = 0.83, n = 51; and water immersion, hWATER = 107.1 (98.1-116), R2 = 0.86, n = 94. The heat transfer coefficient for the pad was the same in the model and volunteers, and equivalent to hWATER. Therefore, for the same DeltaT and heat transfer area, the Arctic Sun's heat transfer rate would equal water immersion. This has important implications for body cooling/rewarming rates.

Characterization of power induced heating and damage in fiber optic probes for near-field scanning optical microscopy.

PubMed

Dickenson, Nicholas E; Erickson, Elizabeth S; Mooren, Olivia L; Dunn, Robert C

2007-05-01

Tip-induced sample heating in near-field scanning optical microscopy (NSOM) is studied for fiber optic probes fabricated using the chemical etching technique. To characterize sample heating from etched NSOM probes, the spectra of a thermochromic polymer sample are measured as a function of probe output power, as was previously reported for pulled NSOM probes. The results reveal that sample heating increases rapidly to approximately 55-60 degrees C as output powers reach approximately 50 nW. At higher output powers, the sample heating remains approximately constant up to the maximum power studied of approximately 450 nW. The sample heating profiles measured for etched NSOM probes are consistent with those previously measured for NSOM probes fabricated using the pulling method. At high powers, both pulled and etched NSOM probes fail as the aluminum coating is damaged. For probes fabricated in our laboratory we find failure occurring at input powers of 3.4+/-1.7 and 20.7+/-6.9 mW for pulled and etched probes, respectively. The larger half-cone angle for etched probes ( approximately 15 degrees for etched and approximately 6 degrees for pulled probes) enables more light delivery and also apparently leads to a different failure mechanism. For pulled NSOM probes, high resolution images of NSOM probes as power is increased reveal the development of stress fractures in the coating at a taper diameter of approximately 6 microm. These stress fractures, arising from the differential heating expansion of the dielectric and the metal coating, eventually lead to coating removal and probe failure. For etched tips, the absence of clear stress fractures and the pooled morphology of the damaged aluminum coating following failure suggest that thermal damage may cause coating failure, although other mechanisms cannot be ruled out.

Heat stress and a countermeasure in the Shuttle rescueman's suit

NASA Technical Reports Server (NTRS)

Doerr, D. F.; Reed, H.; Convertino, V. A.

1992-01-01

Rescue of the astronaut flight crew from a contingency landing may risk exposure of the rescue crew to toxic propellants spilling from potentially ruptured tanks in the crew module area. An Aquala dry diver's suit has been in service by the rescue team to preclude exposure, especially in the water rescue scenario. Heat stress has become a factor of concern in recent years when older and less physically-fit team members work in this suit. Methods: Field testing was initiated using fully instrumented rescue men in a simulated scenario to determine the extent of heat stress. Two tests were accomplished, one in the normal (N) configuration and one with a proposed cooling countermeasure, the Steele vest (S). Results: Heat stress was high as indicated by average rectal temperatures (Tre) of 38.28 degrees C(100.9 degrees F) after the 45 minute protocol. Slopes of the regression equations describing the increase in Tre with time were greater (P less than 0.05) with N (0.073 plus or minus .008) compared to S (0.060 plus or minus .007). Projection of time to the 38.89 degree C (102 degree F) limit was increased by 15.3 percent with the vest. Mean skin temperature (Tsk) was higher (P less than 0.05) in N (38.33 plus or minus .11 degrees C) compared to S (34.33 plus or minus .39 degrees C). Average heart rate was higher (P less than 0.05 in N than S. Sweat loss, as measured by weight loss, was more (P less than 0.05) for N (1.09 plus or minus .09 kg versus 0.77 plus or minus .06 kg). Air usage, while slightly less for S, was not statistically different. Conclusion: The use of the cool vest provided significant relief from thermal stress in spite of the addition of 3.4 kg (7.5 pounds) weight and some loss in mobility.

24 CFR 35.140 - Prohibited methods of paint removal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... control. (d) Heat guns operating above 1100 degrees Fahrenheit or charring the paint. (e) Dry sanding or dry scraping, except dry scraping in conjunction with heat guns or within 1.0 ft. (0.30 m.) of...

Storage of red blood cells with improved maintenance of 2,3-bisphosphoglycerate.

PubMed

Högman, Claes F; Löf, Helena; Meryman, Harold T

2006-09-01

During storage, red blood cells (RBCs) rapidly lose 2,3-bisphosphoglycerate (2,3-DPG) leading to an increase in the affinity for O(2) and a temporary impairment of O(2) transport. Recent clinical evaluations indicate that the quality of transfused RBCs may be more important for patient survival than previously recognized. Glucose-free additive solutions (ASs) were prepared with sodium citrate, sodium gluconate, adenine, mannitol, and phosphates at high pH, a solution that can be heat-sterilized. CP2D was used as an anticoagulant. Additional CP2D was added to the AS to supply glucose. RBCs were stored at 4 degrees C and assayed periodically for intracellular pH (pHi), extracellular pH, glucose, lactate, phosphate, ATP, 2,3-DPG, hemolysis, and morphology. Storage in 175 mL of the chloride-free, hypotonic medium at a hematocrit (Hct) level of 59 to 60 percent resulted in an elevated pHi and the maintenance of 2,3-DPG at or above the initial value for 2 weeks without loss of ATP. The addition of 400 mL of storage solution followed by centrifugation and removal of 300 mL of excess solution to a Hct level of 60 to 66 percent further reduced the chloride concentration, resulting in the maintenance of 2,3-DPG for 4 weeks. Hemolysis was at 0.1 percent at 6 weeks. Improvements in the maintenance of 2,3-DPG were achieved with 175 mL of a chloride-free storage solution with familiar additives at nontoxic concentrations to increase pHi. Adding, instead, 400 mL of storage solution followed by the removal of 300 mL reduced the chloride concentration, increasing the pHi and extending the maintenance of 2,3-DPG to 4 weeks.