We investigate the average time for the earliest particle to hit a spherical absorber when a homogeneous gas of freely diffusing particles with density ρ and diffusivity D is prepared in a deterministic state and is initially separated by a minimum distance l from this absorber. In the high-density limit, this first absorption time scales as l D 1 ln ρl in one dimension; we also obtain the firs...

Kesterite Cu2ZnSnS4 (CZTS) semiconductor has been demonstrated to be a promising alternative absorber in thin film solar cell in virtue of its earth-abundant, non-toxic element, suitable optical and electrical properties. Herein, a low-cost and non-toxic method that based on the thermal decomposition and reaction of metal-thiourea-oxygen sol-gel complexes to synthesize CZTS thin film was develo...

Detection peculiarities of an un-cooled (room temperature) 8×8 pixel array designed to image broadband THz radiation were investigated. Each pixel consists of a thin conductive film absorber on a dielectric membrane with thermopile temperature readout. It was designed and tested for four combinations of two different types of absorber and thermopile materials. The photo-response profile, determ...

We present the results of a 4 day ASCA observation of the Seyfert galaxy MCG{6{30{15, focusing on the nature of the X-ray absorption by the warm absorber, characterized by the K-edges of the highly ionized oxygen, Ovii and Oviii. We con rm that the column density of Oviii changes on a timescale of 10 4 s when the X-ray continuum ux decreases. The signi cant anti-correlation of column density wi...

Polycrystalline thin film solar cells based on copper indium diselenide (CuInSe2) and its alloys and cadmium telluride (CdTe) appear to be the most promising candidates for largescale application of photovoltaic energy conversion because they have shown laboratoryefficiencies in excess of 15%. Heterejunction devices with n-type cadmium sulfide (CdS) films show very low minority carrier recombin...

Solar thermophotovoltaic (STPV) systems convert solar energy into electricity via thermally radiated photons at tailored wavelengths to increase energy conversion efficiency. In this work, we report the design and analysis of a STPV system with 2D photonic crystals (PhCs) using a high-fidelity thermal-electrical hybrid model that includes the thermal coupling between the absorber/emitter/PV cel...

The energy resolved efficiency of two bolometer detector prototypes for ITER with 4 channels each and absorber thicknesses of 4.5 μm and 12.5 μm, respectively, has been calibrated in a broad spectral range from 1.46 eV up to 25 keV. The calibration in the energy range above 3 eV was performed against previously calibrated silicon photodiodes using monochromatized synchrotron radiation provided ...

Literature about entropy generation analysis of a wavy enclosure is scare. In this paper. a FORTRAN cod using an explicit finite-volume method was provided for estimating the entropy production due to the natural convection heat transfer in a cosine wavy absorber solar collector. The volumetric entropy generation terms both the heat transfer term and the friction term were straightly calculated...

Two-directional differential phase contrast images were measured using an x-ray microbeam and a double wedge absorber. The wedge absorber converts the displacement of an x-ray beam that is refracted by an object into change of x-ray intensity. The double wedge absorber made it possible to detect values of two-directional refraction angle with microrad sensitivity simultaneously. By Fourier inte...

Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. It is attributed to the formation of a very thin boundary layer at the absorber plate surface commonly known as viscous sub-la...