نتایج جستجو برای: variations in solar radiation received by earth
تعداد نتایج: 18185245 فیلتر نتایج به سال:
The spectral distribution of the solar radiation reaching the Earth's surface depends on the irradiance emitted by the Sun, the Earth-Sun distance, and the transmission properties of the atmosphere. The changing Earth-Sun distance due to an eccentric orbit implies that the irradiance received at the top of the atmosphere varies with an annual cycle, being 6.9% above and below the yearly mean. T...
using photovoltaic systems is gradually expanded by increasing energy demand. abundance and availability of this energy, has turned to one of the most important sources of renewable energy. unfortunately, photovoltaic systems have two big problems: first, those have very low energy conversion efficiency (in act between 12 and 42 percent under certain circumstances). second, the power produced b...
background: astronauts will be exposed to both chronic space radiation and acute high doses of energetic radiation of solar particle events in long-term deep space missions. the application of radioprotectors in space missions has basic limitations such as their very short time window as well as their acute toxicity and considerable side effects. the aim of the present study was to investigate ...
The solar radiation in the form of electromagnetic waves emitted by the sun, travels the extraterrestrial space without any essential interaction with matter, and reaches the earth’s atmosphere. Therein, the beam solar radiation undergoes physic-chemical processes and experiences scattering by (macro) molecules, dust, or other tiny particles in the air. This process creates the solar radiation ...
آموزش واژه با بهره گیری از یادگیری تلفیقی و نرم افزارهای چند رسانه ای در کلاس های آموزش زبان انگلیسی
the purpose of this study was to investigate the impact of blended learning and multimedia softwares on iranian efl students vocabulary learning. in addition, the present study tried to examine the extent to which multimedia softwares can be applied into efl classes in iran. it also attempted to find out students attitudes toward using these softwares. to this end, 87 iranian efl learners at el...
Introduction & Objective: Biological effects of ultraviolet (UV) radiation on the body of live organisms, have been studied by researchers in recent years. UV affects human organs such as skin, eyes and immune system, as well as animals and plants. The main natural source of UV radiation is the Sun. So, the integral observation of UV levels and their effects at ground level is important to dete...
The atmospheres of terrestrial planets are expected to be in long-term radiation balance: an increase in the absorption of solar radiation warms the surface and troposphere, which leads to a matching increase in the emission of thermal radiation. Warming a wet planet such as Earth would make the atmosphere moist and optically thick such that only thermal radiation emitted from the upper troposp...
the purpose of this study was to investigate the effect of task repetition on accuracy of iranian efl learners ’speaking ability. in order to achieve this purpose, a null hypothesis was developed: there is no statistically significant difference between accuracy speaking ability in iranian efl learners by use of task repetition. ; of course i should mention that, beside this null hypothesis, an...
the solar radiation received by earth surface is one of the most applicable parameter that is so important in hydrology, agriculture, meteorology and climatological modeling. because of very expensive instrument for measuring the radiation, researchers suggested many different experimental equations to estimate this parameter in different climate. seven models which are calibrated for semi-arid...
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