Home About us Contact
|
Home About us Contact | ||
|
|
||
Cooling Effect (cooling + effect)
Selected Abstracts3D Edge Transport Studies with EMC3-EIRENE for the Dynamic Ergodic Divertor (DED) at TEXTORCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-3 2008D. Harting Abstract In this paper we introduce some model extensions to the energy balances of the 3D fluid Monte-Carlo code EMC3 and study their influence on the simulation results for TEXTOR-DED. We implemented local kinetic corrections to the classical parallel heat conductivity of electrons (heat flux limit). Depending on the DED configuration, a cooling effect in the outermost SOL region, resulting from the heat flux limit, can be observed. In addition, also the adiabatic cooling term mnV2, which was neglected before, was implemented into the energy iterations. This term causes a localized cooling of the ions in front of the wall, where the plasma is accelerated towards the first wall. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Human modification of the landscape and surface climate in the next fifty yearsGLOBAL CHANGE BIOLOGY, Issue 5 2002R. S. Defries Abstract Human modification of the landscape potentially affects exchanges of energy and water between the terrestrial biosphere and the atmosphere. This study develops a possible scenario for land cover in the year 2050 based on results from the IMAGE 2 (Integrated Model to Assess the Greenhouse Effect) model, which projects land-cover changes in response to demographic and economic activity. We use the land-cover scenario as a surface boundary condition in a biophysically-based land-surface model coupled to a general circulation model for a 15-years simulation with prescribed sea surface temperature and compare with a control run using current land cover. To assess the sensitivity of climate to anthropogenic land-cover change relative to the sensitivity to decadal-scale interannual variations in vegetation density, we also carry out two additional simulations using observed normalized difference vegetation index (NDVI) from relatively low (1982,83) and high (1989,90) years to describe the seasonal phenology of the vegetation. In the past several centuries, large-scale land-cover change occurred primarily in temperate latitudes through conversion of forests and grassland to highly productive cropland and pasture. Several studies in the literature indicate that past changes in surface climate resulting from this conversion had a cooling effect owing to changes in vegetation morphology (increased albedo). In contrast, this study indicates that future land-cover change, likely to occur predominantly in the tropics and subtropics, has a warming effect governed by physiological rather than morphological mechanisms. The physiological mechanism is to reduce carbon assimilation and consequently latent relative to sensible heat flux resulting in surface temperature increases up to 2 °C and drier hydrologic conditions in locations where land cover was altered in the experiment. In addition, in contrast to an observed decrease in diurnal temperature range (DTR) over land expected with greenhouse warming, results here suggest that future land-cover conversion in tropics could increase the DTR resulting from decreased evaporative cooling during the daytime. For grid cells with altered land cover, the sensitivity of surface temperature to future anthropogenic land-cover change is generally within the range induced by decadal-scale interannual variability in vegetation density in temperate latitudes but up to 1.5 °C warmer in the tropics. [source] Homogeneity analysis of Turkish meteorological data setHYDROLOGICAL PROCESSES, Issue 8 2010Sinan Sahin Abstract The missing value interpolation and homogeneity analysis were performed on the meteorological data of Turkey. The data set has the observations of six variables: the maximum air temperature, the minimum air temperature, the mean air temperature, the total precipitation, the relative humidity and the local pressure of 232 stations for the period 1974,2002. The missing values on the monthly data set were estimated using two methods: the linear regression (LR) and the expectation maximization (EM) algorithm. Because of higher correlations between test and reference series, EM algorithm results were preferred. The homogeneity analysis was performed on the annual data using a relative test and four absolute homogeneity tests were used for the stations where non-testable series were found due to the low correlation coefficients between the test and the reference series. A comparison was accomplished by the graphics where relative and absolute tests provided different outcomes. Absolute tests failed to detect the inhomogeneities in the precipitation series at the significance level 1%. Interestingly, most of the inhomogeneities detected on the temperature variables existed in the Aegean region of Turkey. It is considered that theseinhomogeneities were mostly caused by non-natural effects such as relocation. Because of changes at topography at short distance in this region intensify non-random characteristics of the temperature series when relocation occurs even in small distances. The marine effect, which causes artifical cooling effect due to sea breezes has important impact on temperature series and the orograhpy allows this impact go through the inner parts in this region. Copyright © 2010 John Wiley & Sons, Ltd. [source] Comparison of different earth radiation budget experiment data sets over tropical oceansINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2002Chang-Hoi Ho Abstract We compare radiation budgets derived from different Earth Radiation Budget Experiment (ERBE) archives over the tropical oceans (30S and 30N) from 1985 to 1989. Two ERBE data sets are used. One is taken from the Earth Radiation Budget Satellite (ERBS), and the other from the combined ERBS, National Oceanic and Atmospheric Administration (NOAA) 9, and NOAA 10 satellites. The domain-mean all-sky outgoing longwave radiation (OLR) derived from the combined data set shows a notable change in early 1987 when NOAA 10 replaced NOAA 9. This change is also found in longwave (LW) cloud radiative forcing (CRF), all-sky shortwave (SW) radiation, and SWCRF. The ERBS, however, does not show such changes. We also examine the sensitivity of cloud,radiation interaction to the sea surface temperature (SST) of the tropical oceans. In general, each component of radiative feedbacks derived from the two ERBE data have the same sign, although they show a certain degree of discrepancy in the magnitude. The discrepancy is more notable for averaged quantities over the entire tropical oceans, particularly over the subtropics where convective activities are relatively weak. The combined data show a larger sensitivity of LWCRF and SWCRF to SST than those of the ERBS, consistent with the above results. The response of clouds to an increase in SST has a net cooling effect when using the combined data but has a net heating effect when using the ERBS data (,0.80 W m,2 K,1 versus 0.48 W m,2 K,1). Most of the discrepancies of the net CRF between the two ERBE data sets can be accounted for by the difference in the sensitivity of all-sky OLR (4.52 W m,2 K,1 versus 1.73 W m,2 K,1). Copyright © 2002 Royal Meteorological Society. [source] Performance analysis of a modified two-bed solar-adsorption air-conditioning systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2009K. Sumathy Abstract This paper presents the description and operation of a solar-powered modified two-bed adsorption air-conditioning system with activated carbon and methanol as the working pair. A simple lumped parameter model is established to investigate the performance of this continuous adsorption cycle consisting of a twin adsorber immersed in water tanks, which is measured in terms of the temperature histories, gross solar coefficient of performance and specific cooling power. In addition, the influence of some important design and operational parameters on the performance of the system has been studied. Compared with the conventional system, it is found that the modified system can operate more cycles and at a higher efficiency. The parametric study also shows that the adsorbent mass and the solar collector area have significant effect on the system performance as well as on the system size. Finally, when the system uses gas heater as an auxiliary heat source, it is found that the system can provide a stable cooling effect for a longer period of operation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Esophageal Temperature During Radiofrequency-Catheter Ablation of Left Atrium: A Three-Dimensional Computer Modeling StudyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2006FERNANDO HORNERO M.D., Ph.D. Introduction: There is current interest in finding a way to minimize thermal injury in the esophagus during radiofrequency-catheter ablation of the left atrium. Despite the fact that the esophageal temperature is now being monitored during ablation, the influence of different anatomic and technical factors on the temperature rise remains unknown. Methods and Results: We implemented a three-dimensional computational model that included atrial tissue, epicardial fat, esophagus, aorta, and lung, all linked by connective tissue. The finite-element method was used to calculate the esophageal temperature distribution during a procedure of constant-temperature ablation with an 8-mm electrode, under different tissue conditions. Results showed that the distance between electrode and esophagus was the most important anatomic factor in predicting the esophageal temperature rise, the composition of the different tissues being of lesser importance. The measurement of the esophageal temperature in different sites of the lumen offered differences up to 3.7°C, especially for a short electrode,esophagus distance (5 mm). The difference in the convective cooling by circulating blood around electrode and endocardium did not show a significant influence on the esophageal temperature rise. Conclusion: Computer results suggest that (1) the electrode,esophagus distance is the most important anatomic factor; (2) the incorrect positioning of an esophageal temperature probe could give a low reading for the maximum temperature reached in the esophagus; and (3) the different cooling effect of the circulating blood flow at different atrial sites has little impact on the esophageal temperature rise. [source] Efficacy and safety of a new single-dose terbinafine 1% formulation in patients with tinea pedis (athlete's foot): a randomized, double-blind, placebo-controlled studyJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2006JP Ortonne Abstract Background, Tinea pedis is a common dermatophyte infection with frequent recurrences. Terbinafine (presently used as a 1-week topical treatment of tinea pedis) is now available in a novel topical solution (film-forming solution , FFS), developed to allow single application. Objectives, To demonstrate the efficacy and safety of terbinafine 1% FFS in a randomized, double-blind, placebo-controlled, phase III trial, and to determine relapse or re-infection rate of tinea pedis at 12 weeks. Patients/methods, Fifty-four centres (27 in France; 27 in Germany) enrolled 273 evaluable patients (2 : 1 randomization). Patients applied terbinafine 1% FFS or placebo only once between, under and over the toes, soles and sides of both feet. Efficacy assessments included direct microscopy, mycological culture, and clinical signs and symptoms at baseline, and at weeks 1, 6 and 12 after the single drug application. Results, Effective treatment (negative mycology plus absent/minimal symptoms) at week 6 in the terbinafine 1% FFS group was 63%; vehicle was 17% (P 0.0001). Mycological cure was 72% in the terbinafine group and 21% in the placebo (P 0.0001) at week 6. Clinical signs/symptoms decreased significantly in the active group compared to the placebo. The self-assessment of itching and burning sensation by the patient showed a clear reduction in symptoms starting 15 min after treatment application (this could be attributed to the cooling effect of the FFS). Recurrence (positive culture at 3 months) occurred in 12.5% of the effectively treated patients at week 6 in the terbinafine group. FFS was well tolerated. Conclusion, Terbinafine 1% FFS, single dose application is an effective, safe and convenient treatment for tinea pedis. The relapse/re-infection rate 3 months after the end of single-dose therapy is similar to that previously demonstrated in a study using terbinafine 1% cream for 7 days. [source] The thermal regime of soils in the north of Western SiberiaPERMAFROST AND PERIGLACIAL PROCESSES, Issue 1 2002A. V. Pavlov Abstract The results of long-term stationary observations upon the thermal regime of soils in natural and anthropogenically-disturbed tundra and northern taiga landscapes in the north of Western Siberia are discussed. Quantitative assessments of the heating effect of snow cover and the cooling effect of surface organic layer on soil temperatures in both winter and summer seasons are given. Spatial and temporal variations in the depth of seasonal thaw and soil temperatures in the tundra and taiga zones are outlined. Data on changes in soil temperature regimes following disturbance of surface organic layers are presented. Contemporary tendencies in permafrost degradation induced by climatic warming, changes in the snow cover depth, and anthropogenic impacts are shown. Copyright © 2002 John Wiley & Sons, Ltd. [source] Radiative cooling effect of Hurricane Florence in 2006 and precipitation of Typhoon Matsa in 2005ATMOSPHERIC SCIENCE LETTERS, Issue 2 2009Quanhua Liu Abstract The increasing strength of tropical cyclones may be a response of the Earth's interaction between natural variability and human activities. Negative effects of the severe storms, such as flooding, landslides, damage to properties, and even a number of human casualties, have been reported many times. This study reported other aspects on Hurricanes and Typhoons, which may be beneficial to the world. We found that Hurricane Florence in 2006 decreased radiation energy by , 0.5 × 1020 J to the Earth-atmospheric system, about 10% of the annual global energy consumption. If the amount of energy uniformly distributes over the whole Earth surface and over 1-year time, it corresponds to a power of , 0.003 W m,2 The total forcing power on climate change is 0.24 W m,2, if we only take account for the stored fluxes in water, atmosphere, continents, and heat required to melt glaciers and sea ice. Thus, the shielding effect of solar radiation by tropical storms could contribute to ease global warming. In addition, hurricane and typhoon can ease drought sometimes. This study found that the total rainwater carried by Typhoon Matsa in August 2005 into China's inland amounts to about 135 billion tons. The rainfall over the northern China eased severe drought in summer 2005. Copyright © 2009 Royal Meteorological Society [source] Thermal Characteristics of the Embankment with Crushed Rock Side Slope to Mitigate Thaw Settlement Hazards of the Qinghai-Tibet RailwayACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2009Guoyu LI Abstract: Permafrost (perennially frozen ground) appears widely in the Golmud-Lhasa section of the Qinghai-Tibet railway and is characterized by high ground temperature (,,1°C) and massive ground ice. Under the scenarios of global warming and human activity, the permafrost under the railway will gradually thaw and the massive ground ice will slowly melt, resulting in some thaw settlement hazards, which mainly include longitudinal and lateral cracks, and slope failure. The crushed rock layer has a thermal semiconductor effect under the periodic fluctuation of natural air. It can be used to lower the temperature of the underlying permafrost along the Qinghai-Tibet railway, and mitigate the thaw settlement hazards of the subgrade. In the present paper, the daily and annual changes in the thermal characteristics of the embankment with crushed rock side slope (ECRSS) were quantitatively simulated using the numerical method to study the cooling effect of the crushed rock layer and its mitigative ability. The results showed that the ECRSS absorbed some heat in the daytime in summer, but part of it was released at night, which accounted for approximately 20% of that absorbed. Within a year, it removed more heat from the railway subgrade in winter than that absorbed in summer. It can store approximately 20% of the "cold" energy in subgrade. Therefore, ECRSS is a better measure to mitigate thaw settlement hazards to the railway. [source] | ||||||||||||||||