Ultraviolet waves, because of their short wavelength, have a high energy and considerable damaging effects on surfaces. Protection against ultraviolet radiations is one of the finishing treatments done on surfaces exposed to sunlight. The importance of this issue in relation to human health, due to complications such as skin burns and cancer, is doubled. Up t...

electromagnetic radiation emitted by cell-phones is a new health hazard, especially when they are used inside closed metal bodies such as cars, elevators etc. the modern wireless devices like bluetooth further enhance the effect of this radiation. the present studies were taken to get quantitative information about the actual power density levels to which a human brain is exposed inside a vehic...

the first and second laws of thermodynamics have been employed to evaluate energy and exergetic efficiency of the single effect absorption chiller which is used for air conditioning purpose. the performance analysis has been carried out by developing a computer program in ees and modeling the chiller and its components. to evaluate entropy of the water/lithium bromide solution at any point, an ...

this paper aims at investigating the effects of weld nugget size and expulsion on the mechanical properties of low carbon steel resistance spot welds using tensile-shear test. mechanical performance of spot welds are described in terms of failure mode, peak load and failure energy obtained from the tensile-shear test. the effects of voids and porosity as well as electrode indentation associated...

this work describes the optical and structure properties of nickel sulfide and cobalt sulfide nanoparticles in zsm-5 zeolite. the samples were obtained by sulfidation of the ni2+ and co2+ ion-exchange zsm-5 zeolites in a na2s solution at room temperature. the optical properties of the samples were studied by uv-visible spectroscopy. their crystalline structure and morphology were studied by x-r...

the numerical investigation of computing the rate of radiated solar-energy requires equations as a function of solar-time according to the radiation angle of the sun (β) in the latitude 37°n and the shape. this paper implements the lagrange interpolation to obtain the equations of normal diagram of elements based on data obtained from surveying. also the method of hann-window equation used to e...

human body consists of some tissues among which bone is one of the important living and growing tissue . in this research, energy absorption buildup factor (eabf) values of 27 types of bone have been computed for photon energy 0.03 to 1.5 mev up to 40 mean free path (40mfp) penetration depths. the inner bone tissue, spongiosa and male sternum had the largest values of eabf in low photon energie...

assessing the behavior of composite structures which are subjected to impact loads is one of the important subjects in the field of mechanical sciences. using thin-walled tubes which collapsed and absorbed the impact energy is a well-known method to prevent damages to the other parts of the structures. in this paper, deformations, crushing length, peak load, mean force and energy absorption cap...