نتایج جستجو برای: cooling effect
تعداد نتایج: 1686015 فیلتر نتایج به سال:
knowledge of the warming or cooling effects induced by asphalt or grass covered areas, may improve our understanding of how thermal stress or thermal comfort is created for workers who have to work outdoors for long hours in warm seasons. for this purpose a field measurements were carried out to know the cooling and warming effects of two adjacent areas, one covered with grass and the other wit...
temperature restrictions on aqueous effluents dictate that streams with a temperature higher than the permitted level needed to pass through cooling systems to reduce the effluent temperature before discharge. in this study, by considering the grouping design rules based on pinch technology, an optimum design for a distributed effluent cooling system, has been developed. a counter-flow wet cool...
Parametric study of the influence of cooling channel dimensions on PEM fuel cell thermal performance
In a polymer membrane fuel cell more than half of the chemical energy of hydrogen is converted to heat during generation of electricity. This causes an increase in the cell temperature. The Cooling field design has a significant role in cell cooling. The cell's performance and stability are reduced due to inappropriate heat dissipation. In this paper, the cooling flow and heat transfer in cooli...
The urban heat island (UHI) effect might cause extreme weather, which would seriously affect people’s health, increase energy consumption and cause other negative impacts. To construct urban green spaces is a feasible strategy to effectively weaken the UHI effect. In this study, the cooling effect of green spaces on the UHI effect was carefully investigated in summer and winter in Harbin city. ...
purpose: to compare post-operative pain with cooling photorefractive keratectomy (prk) versus conventional prk. methods: a prospective clinical trial was performed on 94 eyes from 47 patients scheduled for prk. patients were randomly assigned to either cooling or conventional prk. pain was evaluated 6, 12, 24 and 48 hours post-operation using a visual analogue scale (vas). corneal haze, conjunc...
In this research, the effects of cooling rate and high energy electron beam irradiation on the change of crystallinity of polypropylene was investigated. For this work, samples of polypropylene heated to 230 ºC and then rapidly cooled with different speed of cooling. Crystalliny of samples were determined by differential scanning calorimetry and infrared spectroscopy. It was shown that percenta...
Nontraditional approach to explain the thermoelectric cooling is suggested . It is based on the Le ChatelierBraun thermodynamic principle. New effect of cooling and heating of junction of two materials (barrierless thermoelectric cooling) is theoretically predicted, and this effect is different from the Peltier effect (barrier thermoelectric cooling). The suggested thermoelectric effect must be...
Numerical simulation is performed in this study to explore filmcooling enhancement by injecting mist into the cooling air with a focus on investigating the effect of various modeling schemes on the simulation results. The effect of turbulence models, dispersed-phase modeling, inclusion of different forces (Saffman, thermophoresis, and Brownian), trajectory tracking, and mist injection scheme is...
background heat is a harmful factor in workplaces that causes physiologic and cognitive changes in workers. objectives the purpose of this study was to investigate the effect of cooling vest on heat strain and reaction time while wearing chemical-biological-nuclear protective clothes. methods twelve male students with mean age of 25 ± 2 and body mass index (bmi) of 23 ± 1.5 were recruited in th...
in a steam power plant, the temperature of the cooling water leaving the condenser for recyclingshould decrease. this is achieved in a cooling tower. the heller cooling tower does not require waterfor operation, thus, it is a suitable system for use in thermal power plants throughout iran. wind is anenvironmental factor that unfavorably affects the performance of a cooling tower. previous studi...
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