A solar cell or photovoltaic cell is a device which generates electricity directly from visible light. However, their efficiency is fairly low. So, the solar cell costs expensive according to other energy resources products. Several factors affect solar cell efficiency. This paper presents the most important factors that affecting efficiency of solar cells. These effects are cell temperature, M...

In recent years, hybrid organic–inorganic perovskite light absorbers have attracted much attention in the field of solar cells due to their optoelectronic characteristics that enable high power conversion efficiencies. Perovskite-based solar cells’ efficiency has increased dramatically from 3.8% to more than 20% in just a few years, making them a promising low-cost alternative for photovoltaic ...

objectives : this experimental study evaluated the effect of bonding application time on the microshear bond strength of composite resin to different types of glass ionomer cements (gics). materials and methods: one-hundred and sixty specimens (two conventional and two resin-modified gics) were prepared and divided into 16 groups. the surface of all specimens was prepared using two different bo...

this paper presents mathematical models of thin layer forced convection solar drying of cuminum cyminum using two drying methods (mixed and indirect) at different operating conditions. the average initial moisture content of the seeds for all tests was about 43% d.b. and the drying was performed continuously, in each test, for a uniform period of 90 minutes drying time in a solar cabinet dryer ...

A solar concentration system formed by two holographic cylindrical lenses is proposed. It redirects part of the incident solar spectrum towards a PV cell, concentrating only the cell’s most efficient wavelength range, while the rest is transmitted, not causing overheating. Simulations with oneand two-axes tracking are carried out.

introduction: debonding is a common cause of failure encountered with fiber-reinforced composite (frc) posts, and usually occurs along the post space-dentin adhesive interface. the aim of this in vitro study is to evaluate the regional push-out bond strength of a fiber-reinforced post system, using two resin cements. materials and methods: in this in vitro study 20 maxillary central incisors we...

We present a microscopic model for metastable Si dangling-bond defect creation in hydrogenated amorphous silicon, which is applicable to both light-induced defect creation in solar cells ~Staebler-Wronski effect! and bias-stress-induced defect creation in thin-film transistors. Light or gate bias causes electron-hole pairs or electrons, respectively, to be localized on short, weak Si-Si bonds, ...

background: in general, measurements of solar ultraviolet (uv) radiation are related to horizontal surfaces. while the hu­mans walking and standing outdoors expose to the natural solar uv radiation, their eyes, cheeks, extremities, trunks, or many other anatomical sites are close to vertical plane and random orient to different directions. in this study, we character­ized the diurnal variations...