Creep analysis of rotating orthotropic disks

The present paper is devoted to a study of creep deformation and stress distribution in rotating disks of orthotropic materials. Assuming the creep rate to be a function of stress multiplied by a function of time (time-hardening law), expressions for stresses and creep-rates in radial and tangential directions, have been obtained. The basic equations obtained have been solved using a method of successive approximations. A numerical example has been worked out. The effect of transient (non-steady) creep and orthotropicity of the material on stress and strain distributions in the disk has been discussed and depicted graphically.     

Creep analysis of orthotropic circular cylindrical shells

The problem of creep in a thin circular cylindrical shell made of an homogeneous, incompressible and orthotropic material is investigated using a non-steady creep law. Although several analyses concerning material isotropy have been carried out in the past, the important aspect of anisotropy, an indispensable consideration for a rational design, has not so far been studied. The present paper attempts to fill this important gap.The paper develops a method for estimating the numerical values of anisotropic creep constants. The utility of the method is evident from the fact that little data for anisotropic constants is available in literature.The effect of anisotropy is studied and it is shown that the stresses, deflections (strains) and moments are all significantly affected by anisotropy. A comparison of the results for the anisotropic and isotropic cases was made. The results indicate that material anisotropy can be exploited to provide a better shell design. For example, the use of a type II anisotropic material (discussed in the paper) results in the lowest values of deflections and will thus ensure a longer service life for the shell.     

用试铁灵选择性分光光度测定铜

铜的选择性分光光度测定是基于在低酸度下用氯仿中的三苄胺萃取铜试铁灵络合物和在410nm处测定黄色萃取物的吸光度。发现铜的浓度直至8μg/Ml,比耳定律仍然有效。在所试验的30种元素中,只有钼有干扰。萃取中铜:试铁灵:三苄胺之比值为1:2:2。     

Advanced high-velocity oxygen-fuel coating and candidate materials for protecting LP steam turbine blades against droplet erosion

This paper describes the water droplet erosion characteristics of advanced high-velocity oxygen-fuel (HVOF) coating and the materials used for steam turbine blading. For droplet erosion study, round samples as per ASTM G73-98 (“Standard Practice for Liquid Impingement Erosion Testing,” Vol 03.02, Annual Book of ASTM Standards, ASTM, 2004) were selected. The materials commonly used for steam turbine blading are X20Cr13, X10CrNiMoV122, and Ti6Al4V. During incubation as well as in the long run, advanced HVOF coating has performed much better than all these materials. This is due to enhanced particle kinetic energy caused by optimum flow of oxygen and fuel injection by modifying the fuel injector. Droplet erosion test results of these materials and advanced HVOF coating along with their properties and damage mechanism are reported and discussed in this paper.     

Intrusion Detection System Against Colluding Misbehavior in MANETs

Routing protocol of MANET works with the presumption that nodes will transmit the data in collaboration. This presumption is a limitation of routing protocol which gives an occasion to attackers to hinder the security of the device and data in the network. Therefore, it becomes vital to develop methods and systems which will ensure the safety, integrity and confidentiality of data in such devices and systems. Although, existing IDS are able to detect various types of attack but some misbehavior goes undetected which potentially damage the network. Collusion attack is one such misbehavior where nodes perform maliciously in collaboration with neighboring nodes without being detected. In this work, Intrusion detection algorithm has been proposed that can effectively detect and isolate colluding nodes from the network so that these malicious nodes do not affect the performance of the network . Proposed detection algorithm uses in–out traffic information and overhearing statistics of nodes to identify colluding attackers. Detection algorithm works successfully for DSR routing protocol. Experimental results on NS-2 show that the proposed algorithm is capable of reducing the packet drops consequently improving the throughput of the network in presence of collusion attack.