Heat fluxes and surface radiation measurements from Samoylov Island, Lena Delta, Siberia, October 2007 to March 2008

In this study, we present the winter time surface energy balance at a polygonal tundra site in northern Siberia based on independent measurements of the net radiation, the sensible heat flux and the ground heat flux from two winter seasons. The latent heat flux is inferred from measurements of the atmospheric turbulence characteristics and a model approach. The long-wave radiation is found to be the dominant factor in the surface energy balance. The radiative losses are balanced to about 60 % by the ground heat flux and almost 40 % by the sensible heat fluxes, whereas the contribution of the latent heat flux is small. The main controlling factors of the surface energy budget are the snow cover, the cloudiness and the soil temperature gradient. Large spatial differences in the surface energy balance are observed between tundra soils and a small pond. The ground heat flux released at a freezing pond is by a factor of two higher compared to the freezing soil, whereas large differences in net radiation between the pond and soil are only observed at the end of the winter period. Differences in the surface energy balance between the two winter seasons are found to be related to differences in snow depth and cloud cover which strongly affect the temperature evolution and the freeze-up at the investigated pond.

Harmonization of Life Cycle Climate Performance and Its Improvements for Heat Pump Applications

Life Cycle Climate Performance (LCCP) is an evaluation method by which heating, ventilation, air conditioning and refrigeration systems can be evaluated for their global warming impact over the course of their complete life cycle. LCCP is more inclusive than previous metrics such as Total Equivalent Warming Impact. It is calculated as the sum of direct and indirect emissions generated over the lifetime of the system “from cradle to grave”. Direct emissions include all effects from the release of refrigerants into the atmosphere during the lifetime of the system. This includes annual leakage and losses during the disposal of the unit. The indirect emissions include emissions from the energy consumption during manufacturing process, lifetime operation, and disposal of the system. This thesis proposes a standardized approach to the use of LCCP and traceable data sources for all aspects of the calculation. An equation is proposed that unifies the efforts of previous researchers. Data sources are recommended for average values for all LCCP inputs. A residential heat pump sample problem is presented illustrating the methodology. The heat pump is evaluated at five U.S. locations in different climate zones. An excel tool was developed for residential heat pumps using the proposed method. The primary factor in the LCCP calculation is the energy consumption of the system. The effects of advanced vapor compression cycles are then investigated for heat pump applications. Advanced cycle options attempt to reduce the energy consumption in various ways. There are three categories of advanced cycle options: subcooling cycles, expansion loss recovery cycles and multi-stage cycles. The cycles selected for research are the suction line heat exchanger cycle, the expander cycle, the ejector cycle, and the vapor injection cycle. The cycles are modeled using Engineering Equation Solver and the results are applied to the LCCP methodology. The expander cycle, ejector cycle and vapor injection cycle are effective in reducing LCCP of a residential heat pump by 5.6%, 8.2% and 10.5%, respectively in Phoenix, AZ. The advanced cycles are evaluated with the use of low GWP refrigerants and are capable of reducing the LCCP of a residential heat by 13.7%, 16.3% and 18.6% using a refrigerant with a GWP of 10. To meet the U.S. Department of Energy’s goal of reducing residential energy use by 40% by 2025 with a proportional reduction in all other categories of residential energy consumption, a reduction in the energy consumption of a residential heat pump of 34.8% with a refrigerant GWP of 10 for Phoenix, AZ is necessary. A combination of advanced cycle, control options and low GWP refrigerants are necessary to meet this goal.

Seasonal changes of heat and moisture fluxes from the Caspian Sea surface and its effect on synoptic systems with heavy rainfalls in southern shores of the sea during 2005-2010

Caspian Sea with its unique characteristics is a significant source to supply required heat and moisture for passing weather systems over the north of Iran. Investigation of heat and moisture fluxes in the region and their effects on these systems that could lead to floods and major financial and human losses is essential in weather forecasting. Nowadays by improvement of numerical weather and climate prediction models and the increasing need to more accurate forecasting of heavy rainfall, the evaluation and verification of these models has been become much more important. In this study we have used the WRF model as a research-practical one with many valuable characteristics and flexibilities. In this research, the effects of heat and moisture fluxes of Caspian Sea on the synoptic and dynamical structure of 20 selective systems associated with heavy rainfall in the southern shores of Caspian Sea are investigated. These systems are selected based on the rainfall data gathered by three local stations named: Rasht, Babolsar and Gorgan in different seasons during a five-year period (2005-2010) with maximum amount of rainfall through the 24 hours of a day. In addition to synoptic analyses of these systems, the WRF model with and without surface flues was run using the two nested grids with the horizontal resolutions of 12 and 36 km. The results show that there are good consistencies between the predicted distribution of rainfall field, time of beginning and end of rainfall by the model and the observations. But the model underestimates the amounts of rainfall and the maximum difference with the observation is about 69%. Also, no significant changes in the results are seen when the domain and the resolution of computations are changed. The other noticeable point is that the systems are severely weakened by removing heat and moisture fluxes and thereby the amounts of large scale rainfall are decreased up to 77% and the convective rainfalls tend to zero.

Characterization of heat waves affecting mortality rates of broilers between 29 days and market age

Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days.

Dynamic Modeling and Seasonal Performance Evaluation of Air-to-Water Heat Pump Systems

In this Thesis a series of numerical models for the evaluation of the seasonal performance of reversible air-to-water heat pump systems coupled to residential and non-residential buildings are presented. The exploitation of the energy saving potential linked to the adoption of heat pumps is a hard task for designers due to the influence on their energy performance of several factors, like the external climate variability, the heat pump modulation capacity, the system control strategy and the hydronic loop configuration. The aim of this work is to study in detail all these aspects. In the first part of this Thesis a series of models which use a temperature class approach for the prediction of the seasonal performance of reversible air source heat pumps are shown. An innovative methodology for the calculation of the seasonal performance of an air-to-water heat pump has been proposed as an extension of the procedure reported by the European standard EN 14825. This methodology can be applied not only to air-to-water single-stage heat pumps (On-off HPs) but also to multi-stage (MSHPs) and inverter-driven units (IDHPs). In the second part, dynamic simulation has been used with the aim to optimize the control systems of the heat pump and of the HVAC plant. A series of dynamic models, developed by means of TRNSYS, are presented to study the behavior of On-off HPs, MSHPs and IDHPs. The main goal of these dynamic simulations is to show the influence of the heat pump control strategies and of the lay-out of the hydronic loop used to couple the heat pump to the emitters on the seasonal performance of the system. A particular focus is given to the modeling of the energy losses linked to on-off cycling.

The Effect Of Celastrol, A Triterpene With Antitumorigenic Activity, On Conformational And Functional Aspects Of The Human 90kda Heat Shock Protein Hsp90α, A Chaperone Implicated In The Stabilization Of The Tumor Phenotype.

Hsp90 is a molecular chaperone essential for cell viability in eukaryotes that is associated with the maturation of proteins involved in important cell functions and implicated in the stabilization of the tumor phenotype of various cancers, making this chaperone a notably interesting therapeutic target. Celastrol is a plant-derived pentacyclic triterpenoid compound with potent antioxidant, anti-inflammatory and anticancer activities; however, celastrol's action mode is still elusive. In this work, we investigated the effect of celastrol on the conformational and functional aspects of Hsp90α. Interestingly, celastrol appeared to target Hsp90α directly as the compound induced the oligomerization of the chaperone via the C-terminal domain as demonstrated by experiments using a deletion mutant. The nature of the oligomers was investigated by biophysical tools demonstrating that a two-fold excess of celastrol induced the formation of a decameric Hsp90α bound throughout the C-terminal domain. When bound, celastrol destabilized the C-terminal domain. Surprisingly, standard chaperone functional investigations demonstrated that neither the in vitro chaperone activity of protecting against aggregation nor the ability to bind a TPR co-chaperone, which binds to the C-terminus of Hsp90α, were affected by celastrol. Celastrol interferes with specific biological functions of Hsp90α. Our results suggest a model in which celastrol binds directly to the C-terminal domain of Hsp90α causing oligomerization. However, the ability to protect against protein aggregation (supported by our results) and to bind to TPR co-chaperones are not affected by celastrol. Therefore celastrol may act primarily by inducing specific oligomerization that affects some, but not all, of the functions of Hsp90α. To the best of our knowledge, this study is the first work to use multiple probes to investigate the effect that celastrol has on the stability and oligomerization of Hsp90α and on the binding of this chaperone to Tom70. This work provides a novel mechanism by which celastrol binds Hsp90α.

Modeling The Effects Of Temperature And Ph On The Resistance Of Alicyclobacillus Acidoterrestris In Conventional Heat-treated Fruit Beverages Through A Meta-analysis Approach.

In this work, all publicly-accessible published findings on Alicyclobacillus acidoterrestris heat resistance in fruit beverages as affected by temperature and pH were compiled. Then, study characteristics (protocols, fruit and variety, °Brix, pH, temperature, heating medium, culture medium, inactivation method, strains, etc.) were extracted from the primary studies, and some of them incorporated to a meta-analysis mixed-effects linear model based on the basic Bigelow equation describing the heat resistance parameters of this bacterium. The model estimated mean D* values (time needed for one log reduction at a temperature of 95 °C and a pH of 3.5) of Alicyclobacillus in beverages of different fruits, two different concentration types, with and without bacteriocins, and with and without clarification. The zT (temperature change needed to cause one log reduction in D-values) estimated by the meta-analysis model were compared to those ('observed' zT values) reported in the primary studies, and in all cases they were within the confidence intervals of the model. The model was capable of predicting the heat resistance parameters of Alicyclobacillus in fruit beverages beyond the types available in the meta-analytical data. It is expected that the compilation of the thermal resistance of Alicyclobacillus in fruit beverages, carried out in this study, will be of utility to food quality managers in the determination or validation of the lethality of their current heat treatment processes.

Mass loss of four commercially available heat-polymerized acrylic resins after toothbrushing with three different dentifrices

The association between a toothbrush and a dentifrice is the most used denture cleaning method. The purpose of this study was to evaluate the abrasiveness of specific and non-specific denture cleaning dentifrices on different heat-polymerized acrylic resins. Sixteen specimens (90x30x3mm) of each acrylic resin (QC-20, Lucitone 550, Clássico, Vipi-Cril) were prepared and randomly assigned to 4 groups: 1: control (distilled water), 2: Colgate, 3: Bonyplus and 4: Dentu-Creme. The specimens were subjected to simulated toothbrushing in an automatic brushing machine using 35,600 brush strokes for each specimen. Brushing abrasion run at a 200-g load with the specimens immersed in 2:1 dentifrice/water slurry. Specimens were reconditioned to constant mass and the mass loss (mg) was evaluated. Data were analyzed by 2-way ANOVA and Tukey's test (a=0.05). Analysis of dentifrices' abrasive particles was made by scanning electron microscopy. Colgate produced the greatest mass reduction (42.44 mg, p<0.05), followed by Dentu-Creme (33.60 mg). Bonyplus was the less abrasive (19.91 mg), similar to the control group (19.69 mg) (p>0.05). The mass loss values indicated that QC-20 (33.13 mg) and Lucitone 550 (33.05 mg) resins were less (p<0.05) resistant to abrasion than Clássico (26.04 mg) and Vipi-Cril (23.43 mg). In conclusion, Colgate produced the greatest abrasion. Specific dentifrices for dentures tend to cause less damage to acrylic resins.

Heat treatment of a direct composite resin: influence on flexural strength

The purpose of this study was to evaluate the flexural strength of a direct composite, for indirect application, that received heat treatment, with or without investment. One indirect composite was used for comparison. For determination of the heat treatment temperature, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed, considering the initial weight loss temperature and glass transition temperature (Tg). Then, after photoactivation (600 mW/cm² - 40 s), the specimens (10 x 2 x 2 mm) were heat-treated following these conditions: 170ºC for 5, 10 or 15 min, embedded or not embedded in investment. Flexural strength was assessed as a means to evaluate the influence of different heat treatment periods and investment embedding on mechanical properties. The data were analyzed by ANOVA and Tukey's test (α = 0.05). TGA showed an initial weight loss temperature of 180ºC and DSC showed a Tg value of 157°C. Heat treatment was conducted in an oven (Flli Manfredi, Italy), after 37°C storage for 48 h. Flexural strength was evaluated after 120 h at 37°C storage. The results showed that different periods and investment embedding presented similar statistical values. Nevertheless, the direct composite resin with treatments presented higher values (178.7 MPa) compared to the indirect composite resin (146.0 MPa) and the same direct composite submitted to photoactivation only (151.7 MPa). Within the limitations of this study, it could be concluded that the heat treatment increased the flexural strength of the direct composite studied, leading to higher mechanical strength compared to the indirect composite.

Desidratação e recomendações para a reposição hídrica em crianças fisicamente ativas

OBJETIVO: A prática de exercícios físicos, devido à produção inerente de calor, pode conduzir à desidratação. A maioria dos estudos que abordam os riscos da desidratação e fornecem recomendações de reposição hídrica é direcionada a indivíduos adultos residentes em regiões de clima temperado, porém, em regiões tropicais, pouco é conhecido sobre as necessidades de reposição hídrica em crianças fisicamente ativas. Esta revisão discute as recomendações para esta população e estabelece os riscos da prática esportiva em ambiente de clima tropical. FONTES DE DADOS: Análise sistemática com levantamento da literatura nacional (SciELO) e internacional (Medline) de artigos publicados entre 1972 e 2009, com os seguintes descritores isolados ou em combinação: hidratação, crianças, desidratação e reposição hídrica. Foram selecionados artigos publicados nas línguas portuguesa e inglesa. SÍNTESES DE DADOS: Observou-se que há riscos de desidratação e possível desenvolvimento de um quadro de hipertermia principalmente se as crianças são submetidas a condições climáticas desfavoráveis sem reposição hídrica adequada. O principal fator desencadeante da hipertermia é a menor adaptação das crianças aos extremos de temperatura, em comparação aos adultos, por possuírem área maior de superfície corporal e capacidade menor de termorregulação por evaporação. CONCLUSÕES: Conhecidos os fatores intervenientes da desidratação, a melhor recomendação, perante uma condição climática sabidamente desfavorável, é estabelecer um plano impositivo de hidratação com bebida com sabor e acréscimo de carboidratos e sódio, evitando-se uma perda hídrica significativa, diminuição da performance e, principalmente, com o objetivo de reduzir os riscos à saúde impostos pela hipertermia e desidratação a crianças fisicamente ativas.

Hydrometeor and latent heat profiles of tropical cyclones Conson, Ivan and Catarina using PR/TRMM data

ABSTRACT Microphysical and thermodynamical features of two tropical systems, namely Hurricane Ivan and Typhoon Conson, and one sub-tropical, Catarina, have been analyzed based on space-born radar PR measurements available on the TRMM satellite. The procedure to classify the reflectivity profiles followed the Heymsfield et al (2000) and Steiner et al (1995) methodologies. The water and ice content have been calculated using a relationship obtained with data of the surface SPOL radar and PR in Rondonia State in Brazil. The diabatic heating rate due to latent heat release has been estimated using the methodology developed by Tao et al (1990). A more detailed analysis has been performed for Hurricane Catarina, the first of its kind in South Atlantic. High water content mean value has been found in Conson and Ivan at low levels and close to their centers. Results indicate that hurricane Catarina was shallower than the other two systems, with less water and the water was concentrated closer to its center. The mean ice content in Catarina was about 0.05 g kg-1 while in Conson it was 0.06 g kg-1 and in Ivan 0.08 g kg-1. Conson and Ivan had water content up to 0.3 g kg-1 above the 0ºC layer, while Catarina had less than 0.15 g kg-1. The latent heat released by Catarina showed to be very similar to the other two systems, except in the regions closer to the center.

Effect of experimental heat treatment on mechanical properties of resin composites

The aim of this study was to verify the influence of an experimental heat treatment (170ºC/10 min) using a casting furnace on the mechanical properties (hardness and flexural strength) of 2 commercial direct resin composites (TPH Spectrum and Filtek P60) compared to a commercial indirect resin system (BelleGlass). Heat treatment temperature was determined after thermal characterization by thermogravimetry (TG) and differential scanning calorimetry (DSC). Data was analyzed by ANOVA and Tukey's test at 5% significance level. There was statistical significance for the main factor heat treatment (p=0.03) and composite (p=0.02), for flexural strength. For Knoop hardness, only the main factor composite was statistically significant (p=0.00). P60 presented higher hardness than TPH. No statistically significant correlation between mechanical properties tested was detected. Based on these results, it was possible to conclude that heat treatment influenced flexural strength of direct composites, while it was not observed for hardness. The association of direct composites with a simple post-cure heat treatment may be an alternative for current indirect composite systems, although more studies are needed to verify other properties of the composites for this application.

Soy isoflavones reduce heat shock proteins in postmenopausal women

Background: Atherosclerosis and its complications remain the most common cause of death in postmenopausal women. But there are few studies evaluating in hormonal theraphy can affect the autoimmune response involved in atherosclerosis. Objective to evaluate the effects to soy germ isoflavones and hormone replacement theraphy on antibodies against heat shock proteins (HPSP60, HPSP70 and HSC70) in moderately hypertensive hypercholesterolemic postmenopausal women. Methods: Women were treated with soy germ (2g/day) 17'beta'-estradiol(2 mg/day) or 17'beta'-estradiol (2mg/day)+noretisterone acetate (1mg/day), for 3 months after taking placebo for 1 month. The plasma autoantibodies to HSP60, HSP70 and HSC70 were determined by ELISA. Results: Data showed a reduction of autoantibodies against HSC70 after treatment in the 3 studies groups in relation to the placebo. The antibodies reactive to HSP70 were reduced only in women receiving soy germ. No significant differences were found for antibodies against HSP60. Conclusion: The soy germ isoflavones and 17'beta'-estradiol, alone or associated with noretisterone acetate, had similar effects on reduction of antibodies reactive to HSP70 in moderately hypertensive hypercholesterolemic postmenopausal women after 3 months of treatment. Thus, there results indicate that soy isoflavnes and hormone theraphy may modulate some pathways of the immune-inflammatory process in postmenopausal women at high risk for atherosclerosis.

Evaluation of Ti(3)Si Phase Stability from Heat-Treated, Rapidly Solidified Ti-Si Alloys

Ti-base alloys containing significant amounts of silicon have been considered for high temperature structural applications. Thus, information concerning phase stability on the Ti-Si system is fundamental and there are not many investigations covering the phase stability of the Ti(3)Si phase, specially its dependence on oxygen/nitrogen contamination. In this work the stability of this phase has been evaluated through heat-treatment of rapidly solidified Ti-rich Ti-Si alloys at 700 A degrees C and 1000 A degrees C. The rapidly solidified splats presented nanometric scale microstructures which facilitated the attainment of equilibrium conditions. The destabilization of Ti(3)Si due to oxygen/nitrogen contamination has been noted.

Influence of Annealing Heat Treatment and Cr, Mg, and Ti Alloying on the Mechanical Properties of High-Silicon Cast Iron

The influence of annealing on the mechanical properties of high-silicon cast iron for three alloys with distinct chromium levels was investigated. Each alloy was melted either with or without the addition of Ti and Mg. These changes in the chemical composition and heat treatment aimed to improve the material's mechanical properties by inhibiting the formation of large columnar crystals, netlike laminae, precipitation of coarse packs of graphite, changing the length and morphology of graphite, and rounding the extremities of the flakes to minimize the stress concentration. For alloys with 0.07 wt.% Cr, the annealing reduced the impact resistance and tensile strength due to an enhanced precipitation of refined carbides and the formation of interdendritic complex nets. Annealing the alloys containing Ti and Mg led to a decrease in the mechanical strength and an increase in the toughness. Alloys containing approximately 2 wt.% Cr achieved better mechanical properties as compared to the original alloy. However, with the addition of Ti and Mg to alloys containing 2% Cr, the chromium carbide formation was inhibited, impairing the mechanical properties. In the third alloy, with 3.5 wt.% of Cr additions, the mechanical strength improved. The annealing promoted a decrease in both hardness and amount of iron and silicon complex carbides. However, it led to a chromium carbide formation, which influenced the mechanical characteristics of the matrix of the studied material.