Introduction: Attenuation correction is a useful process for improving myocardial perfusion SPECT and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). Attenuation artifacts are a common problem in myocardial perfusion SPECT. The aim of this study was to compare the effect of attenuation correction using different a...

A 3D simulation study for an incompressible slip flow around a spherical aerosol particle was performed. The full Navier-Stokes equations were solved and the velocity jump at the gas-particle interface was treated numerically by imposition of the slip boundary condition. Analytical solution to the Stokesian slip flow past a spherical particle was used as a benchmark for code verification, and e...

this study involved the development and evaluation of a new filtering technique, as based on adaptive free mass load cell. the technique's application in reduction of vibration and impulse noise (commonly added to the sugar cane harvester yield monitoring signals) was tested. this technique is based upon assimilate spring- mass vibration system of weighing scale with a free mass load cell ...

The era of electronic devices in all loads due to the manufacturing technologies replaced many conventional electrical or mechanical loads including lighting loads where Light Emitting Diodes (LEDs) is becoming an emerging technique with many advantages. High frequency switching dc-dc converter is a new technology to control the load and the supply side simultaneously. Due to additional harmoni...

introduction: attenuation correction is a useful process for improving myocardial perfusion spect and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). attenuation artifacts are a common problem in myocardial perfusion spect. the aim of this study was to compare the effect of attenuation correction using different attenuation maps and different...

Using the sampled data of a desired pattern is a common technique in pattern synthesizing of array factor (AF) of antenna arrays. Based on the obtained data matrix, Least Square Method (LSM) is used to calculate the exciting coefficient of array elements. The most important parameter, which involves the accuracy and complexity of calculation, is the sampling rate of the desired pattern. Classic...

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

study area is located in west of iran with relatively rough topography. lithologic units in the region belong from jurassic and cretaccous till recent era. the study area of the alvand mountain region is related to the tectonic zone of the sanandaj-sirjan region and the area dominant neo-tectonic regime appears to be compressional-extensional type. one of the identification tools to find out th...

In erosion and sedimentation problems, estimating the range of significant stream flows to include when computing sediment transport can prove challenging in ungauged or under-gauged basins. This paper describes an event-based model incorporating a geomorphologic instantaneous unit hydrograph and stochastic descriptions of peak flows and frequency of storm events from nearby reference watershed...

This paper deals with a comparative analysis of various converter topologies for Power Factor Correction (PFC) in BLDC motor drives. A power factor corrected converter is required for improving power quality at the AC mains of an inverter fed BLDC motor drive. Conventionally, the BLDC motor is fed by a diode bridge rectifier (DBR) which results in highly distorted supply current and a poor powe...