The operating characteristics of a linear-geometry (open electron drift) Hall thruster are revisited under improved vacuum conditions, in order to eliminate possible channel wall contamination from oil diffusion-pump vapors. A comparison is made between cases in which the thruster is operated with channel walls fabricated from plate diamond, and from boron nitride. These studies reveal a new op...

In this paper, the cooling performance of water-cooled heat sinks for heat dissipation from electronic components is investigated numerically. Computational Fluid Dynamics (CFD) simulations are carried out to study the rectangular and circular cross-sectional shaped heat sinks. The sectional geometry of channels affects the flow and heat transfer characteristics of minichannel heat sinks. T...

Steam reforming integrated with oxidation of methanol was considered with numerical simulation. The parallel micro-channels with circular cross sections were used. Because when the catalytic deposited inside the rectangular micro-channels, it fills up the edges. Hence, the approximation of a cylindrical channel is appropriate. Effect of this changing in cross section was considered and results ...

the subject of geometry and proportions has been regarded as an issue which has a close relationship with architecture. since the entire universe, living beings and the human geometry can be seen clearly, that’s why our unconscious essence has accustomed to these proportions whereby reflection of this mentality can be seen in the architect’s hands and thought in the architecture. it can witness...

Molecular emission enhancement is generally obtained by proper coupling with external resonances. Here we propose the idea of a plasmonic nanolauncher, i.e., a metamaterial-inspired ultranarrow channel at cutoff. Its peculiar operation provides uniform phase and drastic amplitude increase all over the channel, allowing high emission enhancement independent of the position of an individual or gr...

We have developed a picovoltmeter using a Nb dc superconducting quantum interference device for measuring the flux-flow voltage from a small number of vortices moving through a submicron weak-pinning superconducting channel. We have applied this picovoltmeter to measure the vortex response in a single channel arranged in a circle on a Corbino disk geometry. The circular channel allows the vorti...

Ground waves and sky waves measured 209 km and 250 km south of six triggered lightning flashes containing 30 strokes that occurred in the half-hour before sunset on 27 August 2015 are presented and analyzed. We use a cross-correlation technique to find the ionospheric effective reflection height and compare our results to previous techniques that calculate effective height based on the time del...

In 1820, the lower Canadian River meandered through a densely forested floodplain. By 1898, most of the floodplain had been cleared for agriculture and changes in channel geometry and specific stream power followed, particularly channel widening and straightening with a lower potential specific stream power. In 1964, a large upstream hydropower damwas constructed, which changed the flow regime ...

The motion of a cylindrical bead in a fluid contained within a two-dimensional channel is investigated using the boundary element method as a model of a biomolecular-motor-powered microfluidics pump. The novelty of the pump lies in the use of motor proteins (kinesin) to power the bead motion and the few moving parts comprising the pump. The performance and feasibility of this pump design is inv...

The problem under investigation contains a computational simulation of a specific heat exchanger with complex geometry fins. The problem solved is potentially interesting for researchers and engineers working on solar collectors and aerospace industry. It is known that heat transfer enhancement can be achieved by creating longitudinal vortices in the flow. These vortices can be generated by arc...