نتایج جستجو برای: mass attenuation coefficient

تعداد نتایج: 679612  

2003
T. P. Lerch S. P. Neal

The ultrasonic attenuation coefficient of a fluid or solid material is an acoustic parameter routinely estimated in nondestructive evaluation (NDE) and biological tissue characterization. In this paper, a new measurement and analysis technique for estimating the attenuation coefficient as a function of frequency for a fluid or solid is described. This broadband technique combines two establishe...

Journal: :Applied optics 2008
Robert H Stavn Scott J Richter

We propose a direct method of partitioning the particulate spectral scattering coefficient of the marine hydrosol based on the concurrent determination of the concentrations of particulate mineral and organic matter (the total mass of optically active scattering material exclusive of water) with the particulate spectral scattering coefficient. For this we derive a Model II multiple linear regre...

ژورنال: سنجش و ایمنی پرتو 2017

Rhizophora wood exhibits characteristics of interaction with radiation similar to those of water. Recently, a novel model based on MCNP4C code has been proposed for calculation of mass attenuation coefficients for some polymers. The aim of this study is to determine the mass attenuation coefficients for Rhizophora wood in energy range 15.77-60 keV using this model. First, the mentioned model wa...

The need to design blast resistant civilian structures has arisen due to aggressor attacks on many civilian structures around the world. Achieving vibration and wave attenuation with locally resonant metamaterials has attracted a great deal of consideration due to their frequency dependent negative effective mass density. In this paper, metaconcrete, a new material with exceptional properties i...

Introduction: The present study aimed to evaluate the impact of PbO nano and micro-sized fillers on ordinary and heavy concretes for different photon energies. Material and Methods: The MCNPX Monte Carlo code (version 2.6.0) was used for all simulations in the present study. A model of narrow-beam geometry was validated and utilized to calcul...

A. Vyas P. Kumar R. Ravanfar Haghighi S. Chatterjee,

Introduction: The photoelectric attenuation coefficient of substances is known to depend upon the energy E of the photon and the effective atomic number of substances (Zeff) as (Zeffx/Ey).  No definitive values about these indices x, y are given in the literature. The index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0. Method...

2014
Sandeep Gupta Gurdeep Singh Sidhu

Mass attenuation coefficients and partial photon interactions have been calculated theoretically at incident photon energy 1 Kev to 100 GeV for garnet series of gemstones (Grosaularite (GS1), Pyrope(GS2), Spessarlite(GS3), Almandine(GS4), Uvarovite(GS5) and Androdite(GS6) using XCOM software [1]. The values of these parameters have been found to change significantly with incident photon energy ...

2017
Yuvraj Padmini Padmanabhan

Microalgal cultures are usually sparged with CO2-enriched air to preclude CO2 limitation during photoautotrophic growth. However, the CO2 vol% specifically required at operating conditions to meet the carbon requirement of algal cells in photobioreactor is never determined and 1-10% v/v CO2-enriched air is arbitrarily used. A scheme is proposed and experimentally validated for Chlorella vulgari...

Journal: :Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine 2002
Yasutomo Fujii Nobuyuki Taniguchi Kouichi Itoh Kouichiro Shigeta Yi Wang Jing-Wen Tsao Kenji Kumasaki Takashi Itoh

OBJECTIVE To assess the feasibility of a new method of measuring the attenuation coefficient in the liver, which offers less variability of results than the conventional method. METHODS The attenuation coefficient was evaluated on the basis of the following equation with sound field correction: [log(M0 (z)) - tau(z)]. In our system, the attenuation coefficient was also evaluated by the spectr...

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