نتایج جستجو برای: radiography shielding

تعداد نتایج: 28527  

2010
P. V. Y. Jayasree V. S. S. N. Srinivasa Baba Prabhakara Rao P. Lakshman

Shielding prevents coupling of undesired radiated electromagnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding effectiveness of different shields against angle of incidence with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shielding effectiveness of new combination of these materials is ...

1998
Naoteru Odano Jeffrey O. Johnson Richard A. Lillie

Radiation shielding analysis and design calculations were performed for remote maintenance cells of the proposed National Spallation Neutron Source (NSNS) facility. In the analysis, a calculational strategy utilizing coupled high energy Monte Carlo calculations and multidimensional discrete ordinates calculations was implemented to perform an activation analysis and shielding assessment of the ...

ژورنال: سنجش و ایمنی پرتو 2020

In this research, the applicability of several metal hydrides as neutron moderator and shielding for D-D fusion sources has been investigated by MCNPX code. The results have been investigated in three steps to find the materials with lower thermal, fast and total neutron fluxes than conventional shielding materials. The results show relative advantages of LaNi5H6, VH, TiH2, TaH, Mg (BH4)2, YH2,...

Density functional theory methods(DFT) and natural bond orbital (NBO) analysis were used to investigate the effects of isomerism and side chain mutation at a microscopic level on the stability, binding energy and NMR/NQR tensors of structural isomers, L- methionylasparagine (Met-Asn) and L- asparagylmethionine (Asn-Met) in the gas phase. The results represented that the isomerism and side chain...

2012
H. Gargama S. K. Chaturvedi A. K. Thakur

We report optimized design of multilayered electromagnetic shield using real coded genetic algorithm. It is observed that the shielding effectiveness in multilayer design is higher than single layered counterpart of equal thickness. An effort has been made to develop an alternative approach to achieve specific objective of identifying the design characteristics of each layer in the multilayered...

1999
R. T. Santoro

Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shield...

2015
A. R. Farajollahi F. Bouzarjomehri M. Kiani

INTRODUCTION In radiation therapy centers across Iran, protection of normal tissues is usually accomplished by either Cerrobend or lead block shielding. In this study, the influence of these two shielding methods on central axis dose distribution of photon beam a Cobalt unit was investigated in clinical conditions. MATERIALS AND METHODS All measurements were performed for 60Co γ-ray beams and...

Journal: :JACC. Cardiovascular interventions 2012
Helmut W Lange Heiner von Boetticher

OBJECTIVES This study sought to determine the efficacy of patient pelvic lead shielding for the reduction of operator radiation exposure during cardiac catheterization via the radial access in comparison with the femoral access. BACKGROUND Cardiac catheterization via the radial access is associated with significantly increased radiation dose to the patient and the operator. Improvements in ra...

2003
B. B. Phillips B. 8. PHILLIPS

An analysis is made of the charge distribution in a quasi-static thundercloud system with the assumptions that (1) the cloud has a charge separation mechanism at its midpoint and ( 2 ) the conductivity within the cloud is reduced by a given fraction from the free-air conductivity remote from the storm. The charge separation mechanism produces the primary positive dipole of the storm. The analys...

Journal: :Journal of vascular and interventional radiology : JVIR 2006
Ziv Neeman Sergio A Dromi Shawn Sarin Bradford J Wood

PURPOSE High-radiation exposure occurs during computed tomographic (CT) fluoroscopy. Patient and operator doses during thoracic and abdominal interventional procedures were studied in the present experiment, and a novel shielding device to reduce exposure to the patient and operator was evaluated. MATERIALS AND METHODS With a 16-slice CT scanner in CT fluoroscopy mode (120 kVp, 30 mA), surfac...

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