Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to det...

An experimental study is reported on natural convection heat transfer from a helical heating coil to the surrounding fluid. The coil is heated electrically and the surrounding fluid is selected to be water. The range of parameters are: Rayleigh number, 879 ?£ Ra ?£ 780168, Prandtl number, 4.22 ?£ Pr ?£ 10.02, dimensionless coil diameter,7.69 ?£ Dave /d ?£ 10.77, number of coil rings, 2 ?£ N ?£ ...

Introduction: One of the major causes of image non-uniformity in MRI is due to the existence of  non-homogeneity in RF receive and transmit. This can be the most effective source of error in  quantitative  studies  in  MRI  imaging.  Part  of  this  non-homogeneity  demonstrates  the  characteristics of RF coil and part of it is due to the interaction of RF field with the material being  imaged...

this paper presents a new method called vespiary regular hexagonal (vrh) model to calculate parasitic capacitance between conductor wire filaments of one turn of a coil and between conductor wires filament and liner and also total capacitance of n-turns having single-layers, multi-conductor wire filaments of the helix magneto cumulative generator (mcg) coil. the presented method is an analytica...

This paper presents a new method called vespiary regular hexagonal (VRH) model in order to calculate parasitic capacitance between conductor wire filaments of one turn of coil (OTC) and between conductor wire filaments and liner and also total capacitance of one turn of the helix magneto flux cumulative generator (MCG) coil include single-layer conductor wire filaments in form of rectangular cr...

introduction: traumatic arteriovenous fistula (avf) called to an abnormal relationship between artery and vein which occurs in 10% of arterial traumas. if treatment of avf due to trauma delayed, different outcomes including heart failure, varices and varicose ulcers may accure. in case of chronic traumatic avf, open surgery may lead to remarkable outcomes, presence of many lateral veins and var...

pulmonary arteriovenous malformations (avms) are rare vascular malformations of the lung that usually led to a notable risk of serious and life-threatening complications. there is considerable debate about the best management of strategies for the group of patients with diffuse avms. several therapeutic options have been reported for management of this abnormality among which coil embolization ...

In this article, an innovative supervision system will be proposed that can observe and analyze health of Circuit Breaker’s trip coil. The proposed design also logs changes in the coil's quality and informs network supervisor in case of Circuit Breaker (CB) failure. This system injects small direct currents to the Circuit Breaker connections and the trip coil to compute CB’s health and characte...

Helical coil heat exchangers are widely used in industrial applications ranging fromcryogenic processes, air-conditioning, and nuclear reactors to waste heat recovery due totheir compact size and high heat transfer coefficient. In this kind of heat exchangers, flowand heat transfer are complicated. This paper reports a numerical investigation of theinfluence of different parameters such as coil...