This paper reviews the main factors influencing the synthesis of vitamin D, with particular focus on ultraviolet radiation exposure. On the global level, the main source of vitamin D is the sun. The effect of solar radiation on vitamin D synthesis depends to some extent on the initial vitamin D levels. At moderate to high latitudes, diet becomes an increasingly important source of vitamin D due...

It is mandatory to predict the hourly solar radiation received during the average day of each month for different solar energy applications, particularly in design methods, Scientists have developed methods to achieve this using different input parameters. The objective of this study is to compare statistically existing models for estimating the mean hourly global radiation incident on a horizo...

Loadings of tropospheric aerosols have increased substantially over the past 150 yr as a consequence of industrial activities. These aerosols enhance reflection of solar radiation by the Earth-atmosphere system both directly, by scattering light in clear air and, indirectly, by increasing the reflectivity of clouds. The magnitude of the resultant decrease in absorption of solar radiation is est...

Abstract: The tilt angle with the horizon (with respect to the ground) of the solar energy system affects the amount of solar radiation received. This paper suggests a simple and universal method to obtain the optimum tilt angles by estimating the monthly mean daily global solar radiation on tilted surfaces facing directly towards the equator, which is based on monthly average daily global sola...

this study assessed the optimum water need of pepper (capsicum annuum l. cv. california wonder) and the critical irrigation level to be applied in order to achieve a reasonable economic yield in water shortage conditions. in a controlled field experiment involving five different treatments, seasonal evapotranspiration for pepper fluctuated from 89 mm in the severe stress treatment (i0.00) to 1,...

Quantifying spatial and temporal variations in optimal tilt angle of a solar collector relative to a horizontal position assists in maximizing its performance for energy collection depending on changes in time and space. In this study, optimal tilt angles were quantified for solar collectors based on the monthly global and diffuse solar radiation on a horizontal surface across Turkey. The datas...

This paper presents the optimal design and simulation of a grid-connected Photovoltaic (PV) system to supply electric power to meet the energy demand by Electrical Department in University of Tripoli Libya. Solar radiation is the key factor determining electricity produced by photovoltaic (PV) systems. This paper is designed to develop a novel method to calculate the solar photovoltaic generati...

In recent years, installing photovoltaic (PV) systems has become a worldwide trend. The prediction of solar radiation is very important to PV systems for power generation. For the large power-plant installations, the power allocations and scheduling form PV systems becomes an important issue. This paper aims at estimating the GSR for different locations in Brazil. A total of 20 locations spread...

Information about the availability of solar radiation on horizontal surface is essential for the optimum design and study of solar energy systems. For a country like UAE, the efficient application of solar energy seems inevitable because of abundant sunshine available throughout the year. The traditional way of knowing the amount of global solar radiation (GSR) in a particular region is to inst...

In order to provide an efficient conversion and utilization of solar power, solar radiation datashould be measured continuously and accurately over the long-term period. However, the measurement ofsolar radiation is not available to all countries in the world due to some technical and fiscal limitations. Hence,several studies were proposed in the literature to find mathematical and physical mod...