Computer aided evaluation of pipeline current near toroidal HVDCground electrodes

The effect of the return current of an HVDC toroidal electrode on underground metallic installations such as pipelines and cables is evaluated. In order to quantify the effect of HVDC electrodes on the buried conductor, an equivalent model is first presented that takes into account the electrical properties of the pipeline and its surrounding. In particular, infinitely long pipelines with different coatings are considered. The pipelines are assumed to be continuously buried in homogeneous soil and are located in the vicinity of the HVDC electrode. It is found that the voltage gradient in the vicinity of the electrode results in return currents in grounded conductors, the effects of which can extend several kilometers. Protective coatings reduce stray current from local voltage disturbances but have limited effect against distant electrodes     

Effect of Localized Bending at Through‐Flaws in Pressurized Composite Cylinders

An analytical and experimental investigation was conducted to determine the effect of localized bending at through‐flaws in pressurized composite cylinders. A finite‐difference solution was formulated to determine the stress, strain, and displacement fields in the vicinity of a slit. Tests were conducted on 305‐mm‐diameter cylinders made from graphite/epoxy fabric in a (0,?45)s configuration, with axial slits. Surface‐strain‐field measurements made in the vicinity of the slit showed a significant bending, which verified the finite‐difference solution. This significant bending near the slit tip results in a large magnification of the stresses there. An average stress criterion was employed to predict the failure response of these cylinders based on data obtained from coupon specimens. The finite‐difference solution provided correction factors to account for the localized bending. The prediction utilizing this methodology was excellent in all cases. A generalized methodology to assess damage tolerance of structural configurations with notches is proposed.     

Leisure-time physical activity and marital status in relation to depression between men and women: A prospective study.

Background: Previous studies have identified the preventive effect of leisure-time physical activity (LTPA) on depression. Women and men have different emotional vulnerabilities. The impact of LTPA on depression varies by gender. Little is known about the impact of LTPA on depression for people with different marital status. Objectives: The objective of this study was to assess the long-term effects of LTPA, changes in LTPA, and marital status on the risk of developing depression for general Canadians. Methods: Data from the biennial National Population Health Survey (NPHS) cycles conducted between 1994/95 and 2004/05 were analyzed in 2008. After excluding individuals with preexisting depression at baseline, respondents were classified as physically active or inactive and then followed up in subsequent cycles of the NPHS to look at risk of developing depression. Individuals who changed their activity level were also examined. Subgroup analyses by different marital status were performed to identify high-risk populations. Results: In 1994/1995, 17,276 participants were included in the NPHS longitudinal panel. Respondents who were inactive were more likely to be older, female, obese, widowed/separated/divorced, not working, low income, and lacking social support. After controlling for potential confounding factors, it was found that LTPA reduced the risk of developing depression for women. The modest risk reduction observed for men was not statistically significant. Women who were active at baseline and two years of follow-up were significantly less likely to report depression at four years of follow-up compared to women who were inactive at baseline and at two years of follow-up. A 51% greater probability of developing depression was observed after two years for women who changed their LTPA from active to inactive compared to women who remained active. No significant results were found for men. Divorced/separated/widowed women who stopped LTPA had 4.2 times the risk of developing depression after two years compared to those who remained active. The risk of developing depression after stopping activity did not vary according to marital status among men. Conclusions: LTPA has preventive effects on depression for women. Reduction in LTPA level is associated with subsequent depression for women. Divorced/separated/widowed women are at particularly high risk of developing depression if LTPA is stopped. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Theory of the propagation of UHF radio waves in coal mine tunnels

The theoretical study of UHF radio communication in coal mines, with particular reference to the rate of loss of signal strength along a tunnel, and from one tunnel to another around a corner is the concern of this paper. Of prime interest are the nature of the propagation mechanism and the prediction of the radio frequency that propagates with the smallest loss. The theoretical results are compared with published measurements. This work was part of an investigation of new ways to reach and extend two-way communications to the key individuals who are highly mobile within the sections and haulageways of coal mines.     

HVDC Ground Electrode Heat Dissipation

The temperature distribution in the soil surrounding High Voltage Direct Current (HVDC) ground electrodes is determined by using a finite-difference method. This, commonly used numerical method of solution, was selected due to its practicability in obtaining engineering solutions involving both complex ground electrode geometries and boundary conditions. Temperature profiles obtained using this method are also presented.     

Interpretation of resistivity sounding measurements in N-layer soilusing electrostatic images

Geophysical inversion involves the estimation of soil parameters from a set of observations. Multilayer soils are modeled by N horizontal layers with distinct resistivities and depths. For known soil parameters, the apparent resistivity distribution can be computed efficiently from electrostatic images. Since the model responses are generally nonlinear functions of the model parameters, least-squared minimization techniques prove to be useful for evaluating layer resistivities and depths to agree with measurements. This paper demonstrates how electrostatic images can be combined for increasing efficiency in the computation of apparent resistivities and sensitivity factors such as the first and second gradient of the distance with respect to the model parameters. The factors are then used to solve the more demanding task of resistivity interpretation of measurements from Wenner, Schlumberger, Dipole or alternate electrode configurations. Results are presented for two-layer soil and for actual cases with three layer soil     

Differential effects of sphingomyelin hydrolysis and cholesterol transport on oxysterol-binding protein phosphorylation and Golgi localization

The deposition of de novo synthesized and lipoprotein-derived cholesterol at the plasma membrane and transport to the endoplasmic reticulum is dependent on sphingomyelin (SM) content. Here we show that hydrolysis of plasma membrane SM in Chinese hamster ovary cells by exogenous bacterial sphingomyelinase resulted in enhanced cholesterol esterification at the endoplasmic reticulum and rapid dephosphorylation of the oxysterol-binding protein (OSBP), a cytosolic/Golgi receptor for oxysterols such as 25-hydroxycholesterol. After sphingomyelinase treatment, restoration of OSBP phosphorylation closely paralleled resynthesis of SM and down-regulation of cholesterol ester synthesis. SM hydrolysis activated an okadaic acid-sensitive phosphatase that was not stimulated in Chinese hamster ovary cells by short chain ceramides. Agents that specifically blocked sphingomyelinase-mediated delivery of cholesterol to acyl-CoA:cholesterol acyltransferase (U18666A) or promoted cholesterol efflux to the medium (cyclodextrin) did not inhibit OSBP dephosphorylation. SM hydrolysis also promoted OSBP translocation from a vesicular compartment to the Golgi apparatus. Cyclodextrin and U18666A also caused OSBP translocation to the Golgi apparatus, suggesting that OSBP movement is coupled to changes in the cholesterol content of the plasma membrane or Golgi apparatus. These results identify OSBP as a potential target of SM turnover and cholesterol mobilization at the plasma membrane and/or Golgi apparatus.     

Evaluation of the effect of vertical faults on the voltagedistribution around HVDC electrodes using a supercomputer

An effective method for evaluating the electric field, the voltage distribution, and the current density near geological faults in the earth is presented. In order to quantify the effect of HVDC (high-voltage direct current) electrodes, it is necessary to determine the voltage distribution and current flow in the ground. Electrostatic theory is used to generate a voltage solution which must satisfy the Laplace equation and boundary conditions along vertical faults. The voltage distribution around a HVDC toroidal electrode is shown for an actual case. The image theory is used to account for the effect of vertical faults and horizontal soil layers. A supercomputer is utilized to generate a sufficient amount of images to insure that the boundary conditions are met within a desired accuracy     

In vitro kinetics of drug release and pulmonary retention of microencapsulated antibiotic in liposomal formulations in relation to the lipid composition

Today's society seems enthralled with serial killers in the news and the media. Forensic psychiatrists often interview serial killers after they have been caught. There are retrospective studies and case reports of individuals who have committed sexually sadistic serial murders. However, there exists a dearth of case reports on adolescents who have expressed serious fantasies about becoming serial killer prior to actualizing their fantasy. This article presents nine clinical cases of 14- to 18-year-olds who have clinically significant fantasies of becoming a serial killer. Similarities exist in these adolescent cases when compared with retrospective studies and case reports of serial killers on the role of sexually sadistic fantasies and actual killings. Since it has been established that sexual paraphilias may develop at a young age, one can surmise that sadistic paraphilias may also develop in some adolescents. The question is posed, can we predict which of these adolescents may go on to actually become serial killers? This article focuses on how the sexually sadistic fantasy can eventually be acted out and possible motives for the act to be repeated multiple times. Finally, recommendations are made about assessing and treating a youngster who expresses violent sexually sadistic killing fantasies so that attempts can be made to interrupt the progression to actual killing.     

On the Role of Lengthscale in the Prediction of Failure of Composite Structures: Assessment and Needs

The role of modeling in the design of structural composite components against failure is discussed. Composite materials fail due to damage processes operating at several lengthscales. The interactions between these processes offer the principal challenges to applying mechanism-based models at structural scales beyond the ply level. A methodology is proposed to increase the efficiency of the design process, analogous to the 'building block' approach, which provides a framework for integrating mechanism-based models with the current experimentally-based design process. Available models are reviewed and their key elements identified. General concepts are illustrated via a discussion of the particular issues pertaining to notched components. Key steps needed to allow the evolution of the design process to the envisioned process are identified.