Abstract As a reflector of the high-precision measurement system, reflecting surface RMS has significant impact on accuracy entire system. Currently, studies honeycomb sandwich structures mainly focus optimization with lightweight as goal and stiffness strength constraints. And temperature deformation are limited. Consulting equivalent theory, this paper studied influence geometric parameters s...

In this research, geometrical structures of armchair single walled boron nitride nanotube (SWBNNT) and armchair single walled aluminum nitride nanotube (SWAlNNT) were optimized by Density Functional Theory (DFT) in the gas phase, both having the same length of 5 angstrom and n=9, m=9. B3LYP/6-31G* level of theory have been used to determine and compare electronic properties, n...

In this research, geometrical structures of armchair single walled boron nitride nanotube (SWBNNT) and armchair single walled aluminum nitride nanotube (SWAlNNT) were optimized by Density Functional Theory (DFT) in the gas phase, both having the same length of 5 angstrom and n=9, m=9. B3LYP/6-31G* level of theory have been used to determine and compare electronic properties, n...

Abstract In this paper, multi-objective optimization (MOO) of Al2O3-water nanofluid flow in microchannel heat sinks (MCHS) with triangular ribs is performed using Computational Fluid Dynamics (CFD) techniques and Non-dominated Sorting Genetic Algorithms (NSGA II). At first, nanofluid flow is solved numerically in various MCHS with triangular ribs using CFD techniques. Finally, the CFD data will...

Centrifugal Compressors play an essential role in oil, gas and petrochemical industries. Their extensive usage is due to their smooth operation and high reliability compared to other other compressor types. One of the main characteristics of these turbomachines is their performance curve, which is an important criterion for selecting the appropriate compressor for a desired working condition. I...

Capacitive Micro-machined Ultrasonic Transducers (CMUTs) are the ultrasonic devices which produce better features in contrast to piezoelectric transducers. The intrinsic parameter of CMUT varies with the variation in geometrical dimension of the device. The cavity height and the radius of the CMUT with circular membrane is varied in the lumped parallel plate model for its impact on the paramete...

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In this paper, a ray-tracing technique to predict the propagation channel parameters in indoor scenarios is presented. It is a deterministic technique, fully three-dimensional, based on geometrical optics (GO) and the uniform theory of diffraction (UTD). A model of plane facets is used for the geometrical description of the environment. The ray tracing is accelerated considerably by using the A...

Hydraulic fracturing (HF), as a stimulation technique in petroleum engineering, has made possible the oil production from reservoirs with very low permeability. The combination of horizontal drilling and multiple HF with various perforation angles has been widely used to stimulate oil reservoirs for economical productions. Despite the wide use of HF, there are still ambiguous aspects that requi...