Attenuation Coefficient
Mostrando 1-12 de 49 artigos, teses e dissertações.
-
1. Higher Order Mode Attenuation in Microstrip Patch Antenna with DGS H Filter Specification from 5 to 10 GHz Range
Abstract This work proposes the application of a slot in the ground plane, Defected Ground Structure (DGS), of a microstrip patch antenna. The application of this technique aims to attenuate higher-order excited modes without deteriorating the antenna parameters in the fundamental mode. The methodology for the design of the slot in H-format is presented, bas
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
-
2. Evaluation of a Metal-Organic Composite (Tungsten-Lignin) for Attenuation of Gamma Radiation
The objective of this work was to use tungsten and lignin as precursors to obtain a metal-organic composite tungsten-lignin (W-Lig) using different sintering temperatures. Tungsten is a refractory metal and it was selected for the composite since it is widely used for high-energy radiation shielding as it has an excellent absorption cross section for thermal
Mat. Res.. Publicado em: 02/09/2019
-
3. Elemental concentration via portable x-ray fluorescence spectrometry: Assessing the impact of water content
RESUMO A fluorescência de raios-X portátil (pXRF) pode ser considerada como um dos principais avanços para a caracterização química de diferentes materiais. A umidade das amostras pode afetar o desempenho dessa análise. Assim, foi realizado um ensaio para verificar o efeito da umidade na concentração elementar obtida via pXRF. Como inovação, objet
Ciênc. agrotec.. Publicado em: 27/05/2019
-
4. Gamma Ray and FTIR Studies in Zinc Doped Lead Borate Glasses for Radiation Shielding Application
Gamma ray shielding properties of borate glass samples containing oxides of lead and zinc are prepared by melt and quench technique and evaluated theoretically using XCOM computer software for gamma ray shielding properties. However, gamma ray shielding properties are discussed in terms of various calculated parameters such as half value layer, mean free pat
Mat. Res.. Publicado em: 14/11/2018
-
5. Enhancing quality in Diffusion Tensor Imaging with anisotropic anomalous diffusion filter
Abstract Introduction: Diffusion tensor imaging (DTI) is an important medical imaging modality that has been useful to the study of microstructural changes in neurological diseases. However, the image noise level is a major practical limitation, in which one simple solution could be the average signal from a sequential acquisition. Nevertheless, this approac
Res. Biomed. Eng.. Publicado em: 12/09/2017
-
6. Partitioning of the diffuse attenuation coefficient for photosynthetically available irradiance in a deep dendritic tropical lake
ABSTRACT We studied the effects of particulate and dissolved optically active components on the attenuation of photosynthetic active radiation (PAR) in a tropical lake. The temporal and spatial distribution of tripton, Chl-a and aCDOM(440) and their relative contribution to the diffuse PAR attenuation coefficient (Kd) was investigated at 21 sites (dry and we
An. Acad. Bras. Ciênc.. Publicado em: 2017-05
-
7. Propagation of waves in micropolar generalized thermoelastic materials with two temperatures bordered with layers or half-spaces of inviscid liquid
The aim of the present paper is to study the propagation of Lamb waves in micropolar generalized thermoelastic solids with two temperatures bordered with layers or half-spaces of inviscid liquid subjected to stress-free boundary conditions in the context of Green and Lindsay (G-L) theory. The secular equations for governing the symmetric and skew-symmetric l
Lat. Am. j. solids struct.. Publicado em: 2014-12
-
8. Rayleigh waves in isotropic microstretch thermoelastic diffusion solid half space
This paper is devoted to the study of propagation of Rayleigh waves in a homogeneous isotropic microstretch generalized thermoelastic diffusion solid half-space. Secular equations in mathematical conditions for Rayleigh wave propagation are derived for stress free, insulated/impermeable and isothermal/isoconcentrated boundaries. The phase velocity, attenuati
Lat. Am. j. solids struct.. Publicado em: 2014-03
-
9. Implementation of acoustic materials to the VLS-1 Fairing - a sensitivity analysis using SEA
Satellite launchers are submitted to severe acoustic loads mainly during lift-off where SPL achieve, at the upper parts, values within the range of 140-160 dB. Such an excitation can damage embedded elements, if energy attenuation measures are not adopted. In view of managing the PLF vibro-acoustic environment, numerical techniques are applied to predict ela
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-03
-
10. Avaliação comparativa dos coeficientes de Hounsfield entre a tomografia computadorizada de feixe cônico e tomografia multislice / Comparative evaluation of the coefficients of Hounsfield between cone computed tomography and multislice CT
The aim of this study was to compare the attenuation coefficients (Hounsfield Unit) in both cone-beam computed tomography (CT) and multislice CT images. The 40-channel CT scanner (SOMATOM Sensation 40 - Siemens) was used to obtain images (n=20) of macerated mandibles considering the following protocol: axial slices of 0.7 mm in thickness and an interval of 0
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/02/2011
-
11. Heterogeneity correction in the construction of optimized planning in radiotherapy using linear programming
A radiotherapy planning is considered optimal when all the parameters involved, physical or biological, have been investigated and appropriate for each patient. In this type of planning, the major concern is with the tumor irradiation with the minimum possible damage to healthy tissues of the irradiated region, especially the organs at risk. The optimal plan
Pesquisa Operacional. Publicado em: 2011-12
-
12. A study of axi-symmetric waves through an isotropic thermoelastic diffusive medium
The paper deals with the propagation of axial symmetric cylindrical surface waves in a cylindrical bore through a homogeneous isotropic thermoelastic diffusive medium of infinite extent. The three theories of thermoelasticity namely, Coupled Thermoelasticity (CT), Lord and Shulman (L-S) and Green and Lindsay (G-L) are used to study the problem. The frequency
Computational & Applied Mathematics. Publicado em: 2011