In principle, suppression of on-axis stellar light by a coronagraph is easier on an unobscured aperture telescope than on one with an obscured aperture. Recent designs such as the apodized pupil Lyot coronagraph, the ‘band-limited’ Lyot coronagraph, and several variants of phase mask coronagraphs work best on unobscured circular aperture telescopes. These designs are developed to enable the dis...

Dust devils are common but meteorologically unique phenomena on Earth and on Mars. The phenomenon produces a vertical vortex motion in the atmosphere boundary layer and often occurs in hot desert regions, especially in the afternoons from late spring to early summer. Dust devils usually contain abundant wind energy, for example, a maximum swirling wind velocity of up to 25 m/s, with a 15 m/s ma...

The widespread trend of pursuing higher efficiencies in radial turbochargers led to the prompting this work. A 3D-printed model static parts a variable geometry turbine, vaned nozzle, and volute, was developed. This up-scaled from actual reference turbine place sensors characterize flow around nozzle vanes, including tip gap. In study, computational scaled-up carried out verify results two ways...

danehkhoshk anticline is a typical growing anticline in kermanshah province which is located in folded zagros belt. the purpose of this research is to evaluate the effect of tectonic on the triangular facet characteristics, the drainage density and on the drainage pattern formed on anticline. dimensions of triangular facets were determined by means of quickbird satellite images and field works....

In recent years, as the mobile equipment advances, higher output and higher energy density are required of the battery which drives the mobile equipment. As one of the solutions, development of portable fuel cells (DMFC) with methanol used for fuel has been progressed and the fuel cells will be soon put to practical use. The authors have developed a small air pump (0.2W output), which is mounte...

This paper deals with new concept of compressed air energy storage system using atmospheric air at ambient temperature as a zero pollution power source for running motorbikes. The proposed motorbike is equipped with an air turbine in place of an internal combustion engine, and transforms the energy of the compressed air into shaft work. The mathematical modeling and performance evaluation of su...

A novel method of cooling rolls in hot rolling is proposed. This uses a combination solid jet nozzles and specially shaped deflecting vanes. The vanes transform the incoming cylindrical water into flat fan. Thereby, coolant can be directed hardly accessible locations whilst maintaining optimal angle impingement. allow for effectively roll surface near gap, which otherwise not possible with clas...

In axial compressors, the unsteady flow caused by interaction between dynamic and static cascades will make moving vanes subject to periodic forces increase risk of high-cycle fatigue fractures. this study, an “S”-type bowed guide vane was designed a 1.5-stage compressor model established. For five with different bending coefficients, numerical simulation carried out under design conditions nea...

Abstract In this article, a numerical investigation of the effect miniaturized five-hole probe downstream transonic low-pressure turbine vane row is presented. First, calibration was performed in uniform flow conditions, as case for any traditional calibration, wide range Mach number, yaw angle, and pitch angle conditions. The on general field throughout segments then evaluated by performing co...