Papers by Keyword: Scattering

Paper TitlePage

Authors: Chong Myoung Lee, Joseph L. Rose, Youn Ho Cho
Abstract: Rail represents one of the most important means of transportation. Many nondestructive testing methods have been used to find defects in rail. The guided wave technique is the most efficient because of its long propagation characteristic along the rail. The wave structure of the rail cross-section for a particular loading condition of modes and frequencies is an important feature. The wave structures are examined at different modes and frequencies. The propagation scattering patterns of guided waves from various multiple defects in a rail are also studied using finite element method.
788
Authors: Chong Myoung Lee, Joseph L. Rose, Wei Luo, Youn Ho Cho
Abstract: Rail represents one of the most important means of transportation. Many nondestructive testing methods have been used to find defects in rail. The guided wave technique is the most efficient because of its long propagation characteristic along the rail. Potential for detecting transverse cracks exists whereas standard bulk wave technique could miss the cracks. The wave structure of the rail cross-section for a particular loading condition of modes and frequencies is an important feature. In this paper, the propagation and scattering patterns of guided waves in a rail are studied using finite element methods. The wave structures are also examined. Various multiple defect situations and rail boundary conditions can also be studied.
784
Authors: Fang Lin
Abstract: To detect black smokers is the hot topic nowadays. The arounding mineral resources is the human wealth, which has extensive researchful significance. The submarine volcanic eruptions can cause thermal plume and the air curtain group. This paper study the acoustic characteristics of the air bubble, and built the simulation model of air curtain group. With pool for experimental platform, we make the formation process of the air curtain, and experiment with acoustic method to detect air curtain. After processing the data, analyze its fluctuation rate to judge the existence of air curtain. To verify feasibility of this method.
333
Authors: Hong Xia Wang, Qing Hua Zhang, Hong Hui Sun
Abstract: Carbon nanofibers is a new kind of electromagnetic wave absorbing materials and it is expected as a new kind of smoke interference agent. To study the scattering and extinction characteristics of carbon nanofibers, the electromagnetic scattering calculating model was established, and the induced current equation was solved by moment method, as well as the relationship between the infrared extinction cross section and the length of carbon nanofibers was analyzed and calculated based on MATLAB. The results show that when the conductivity of carbon nanofibers is large, the extinction cross section appears a series of resonant peaks along with the length change, and when the length of carbon nanofibers is equal to the first resonant length, the extinction cross section of unit volume will reach the maximum value, and a good extinction effect can be achieved at the same time. The contribution of scattering to extinction is enhanced with the increase of electrical conductivity.
220
Authors: K.M. Zeyde
Abstract: This paper describes the reception, researching and electrodynamics investigations of recently obtained materials. These materials demonstrated the losses dielectric behavior and represent a wide interest as radio markers with controlled distortion. The investigated samples can be used as a coating for rotating machine elements for radio diagnostics. The considered materials performed by epoxy warp with high dispersity metal powder content established the required properties for iron 60 % and nickel 60 %. Primary materials parameters are taken in the natural experiment and electrodynamics properties are studied based on a mathematical model. The presented results can be extended to seminatural experiment setup in future. This paper does not contain the formulation of electrodynamic problem.
90
Authors: Jian Jun Chen, Zhen Ma, Xue Ting Duan, Qiong Liu, Juan Han, Xing Fu
Abstract: For the purpose of stray light suppression, black anodized and sandblasted aluminum alloy is widespread used in spaceborne cameras. Base on the relative measuring method, in the white light irradiation, measure relative backscatter intensity and BRDF of two black anodized and sandblasted sample surfaces. Contrast these surfaces scattering characteristics. Finally BRDF curves have been drawn with measurement data. In the curves, the BRDF of sandblasted aluminum surface is nearly linear relation. Anodized surface curve, it’s pulse pattern that BRDF sharply increases among the region of critical angles. It is indicate that in critical angle range, anodized aluminum surface specularity is visible and can be treated as specular reflection which harm for stray light suppression. This experiment research can provide objective reference of these two material’s scattering characteristics in specific optical system design.
115
Authors: Fei Long Feng, Jian Zhong Shen, Jing Jun Deng, Qiu Ping Wang
Abstract: An analytical solution based on modal decomposition is presented to investigate Lamb wave scattering at plate end. Take boundary condition into biorthogonality relation, a matrix equation is established with all matrix elements have analytical expressions. The scattering feature is then expressed in matrix form, named as reflection matrix, which has explicit expression composed of those matrixes. Calculation examples have be implemented when antisymmetric modes are reflected. Scattering coefficients are figured out in a range when frequency-thickness product vary from 0 to 8kHzm, to prove the calculation efficiency. The calculation precision is very close to the least square method based on model discretization.
949
Authors: M.H. Sajid, Z. Said, Rahman Saidur, Mohd Faizul Mohd Sabri
Abstract: Alumina nanofluid has unique thermo-physical properties which make it appreciable as thermal fluid, but its high extinction coefficient is not significant enough for making it a good solar irradiation absorber. The investigation was conducted on 0.05% v/v water-based alumina nanofluid and results showed that the nanofluid is able to attenuate approximately 50% of solar energy irradiated on the earth surface. Enhancement in absorption coefficient is found very little to increase absorptivity of basefluid using Rayleigh approach. It is found that the scattering coefficient of alumina is dominating absorption coefficient. Although high value of extinction coefficient is observed as usual, scattering is found responsible for this high extinction. The Rayleigh approach cannot explain the optical behaviour of the nanofluid and dominating scattering behaviour points toward alumina nanofluids’ weak capability as radiation absorber.
366
Showing 1 to 10 of 66 Paper Titles