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...

A sample of 908 C iv absorber components clumped in 188 systems outside the Lyman forest in the redshift range 1.6 . z . 4.4 have been identified in Keck HIRES spectra of nine QSOs. These and corresponding lines of Si iv, C ii, Si ii and N v have been fitted with Voigt profiles to obtain column densities and C iv Doppler parameters. The properties of the C iv absorbers are almost constant altho...

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...

The first detector prototypes for the ITER bolometer diagnostic featuring a 12.5 μm thick Pt-absorber have been realized and characterized in laboratory tests. The results show linear dependencies of the calibration parameters and are in line with measurements of prototypes with thinner absorbers. However, thermal cycling tests up to 450 °C of the prototypes with thick absorbers demonstrated th...

Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at approximately 7 km s-1 resolution, reveals four definite O vi absorption-line systems and one probable O vi absorber at 0.15<zabs<0.27. The four definite O vi absorbers are located near galaxies and are highly displaced from the quasar in redshift; these are...

introduction the significant of solar energy as a renewable energy source, clean and without damage to the environment, for the production of electricity and heat is of great importance. furthermore, due to the oil crisis as well as reducing the cost of home heating by 70%, solar energy in the past two decades has been a favorite of many researchers. solar collectors are devices for collecting ...

The International Muon Ionization Cooling Experiment (MICE) is devoted to a study of a muon cooling channel capable of giving the desired performance for a Neutrino Factory. One of the goals is achieving an absolute accuracy of measurements of emittance reduction as high as ±0.1%. The paper describes results of a Monte Carlo study on allowed density variations of liquid hydrogen corresponding t...

In this study, the energy analysis of a solar air heater with an absorber plate made different obstacles was made. Absorber created porous steel wool. Three plates were used for experimental study. Complex (Type I) as first type plate, less complex II) second and flat III) third plate. On these plates, which are manufactured three wools placed in way. One left empty. experiments, mass-flow rate...

An infrared perfect absorber based on a gold nanowire metamaterial cavities array on a gold ground plane is designed. The metamaterial made of gold nanowires embedded in an alumina host exhibits an effective permittivity with strong anisotropy, which supports cavity resonant modes of both electric dipole and magnetic dipole. The impedance of the cavity modes matches the incident plane wave in f...