Thermodynamic and Kinetic Studies of Uranium and REEs Leaching by Oxalic Acid from Abu-Tartur Phosphate Rock,Western Desert,Egypt

Radiochemistry - Leaching of uranium and REEs with oxalic acid from the Egyptian Abu-Tartur phosphate rock (PR) was studied. The effect exerted on the leaching process by oxalic acid concentration,...     

Dielectric properties of SBR vulcanizates loaded with HAF carbon black and BaTiO3 ceramics

The influence of HAF carbon black and BaTiO₃ ceramic powder contents in SBR vulcanizates on the dielectric constant (ε′) at different frequencies and at fixed temperature of 303 K is studied well in this article. The temperature dependence of the ac conductivity (σ_ac) was also studied. ε′ appreciably decreases as frequency increased for both filled and unfilled SBR vulcanizates. At each frequency, ε′ gradually decreased with BaTiO₃ loading, but its change at any fixed frequency with BaTiO₃ filler loading is not uniform. For HAF group ε′ (at loading ≥ 40 phr), drops rapidly with frequency. Meanwhile, it increased appreciably beyond a certain HAF filler loading (≈ 20 phr). Experimental values of the dielectric constant of both BaTiO₃ and HAF contents were compared with those calculated by using Tsangaris, Clausius and Bruggman models. Tsangaris model with simple modifications was applied and a fairly good agreement was obtained. The HAF particles or aggregates was found to take the shape of oblate ellipsoids with the minor axes parallel to the applied frequency as detected from the decreasing behavior of the depolarizing factor (Y) with HAF contents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2227–2234, 2007     

Correction to Vogt et al. (2011).

Reports an error in "Predeployment, deployment, and postdeployment risk factors for Posttraumatic Stress symptomatology in female and male OEF/OIF veterans" by Dawne Vogt, Brian Smith, Rani Elwy, James Martin, Mark Schultz, Mari-Lynn Drainoni and Susan Eisen (Journal of Abnormal Psychology, Advanced Online Publication, Jun 27, 2011, np). In the article there was an error in the affiliation bylines for Rani Elwy and Susan Eisen. Their affiliations should have been listed as Edith Nourse Rogers Memorial Veterans Hospital and Department of Health Policy and Management, Boston University School of Public Health. (The following abstract of the original article appeared in record 2011-13218-001). Prior research on risk factors for posttraumatic stress symptomatology (PTSS) in war-exposed Veterans has revealed both direct and indirect mechanisms of risk that span predeployment, deployment, and postdeployment timeframes. The aims of the present study were to identify the mechanisms through which previously documented risk factors contribute to PTSS in a national sample of 579 female and male Veterans deployed to Afghanistan for Operation Enduring Freedom (OEF) or to Iraq for Operation Iraqi Freedom (OIF), as well as to examine the extent to which results mirror associations observed among Vietnam Veterans (King, King, Foy, Keane, & Fairbank, 1999). Consistent with conservation of resources (COR) theory (Hobfoll, 1989, 2001), findings indicated that PTSS is accounted for by multiple chains of risk, many originating in predeployment experiences that place Veterans at risk for additional stress exposure, and foretell difficulty accessing resources in the face of subsequent stressors. Importantly, the majority of previously documented mechanisms were replicated in this study, suggesting key pathways through which risk factors may contribute to PTSS across different Veteran populations. Results also revealed a number of novel risk mechanisms for OEF/OIF female Veterans, particularly with respect to the role of deployment family relationships in risk for PTSS. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Predeployment, deployment, and postdeployment risk factors for posttraumatic stress symptomatology in female and male OEF/OIF veterans.

[Correction Notice: An erratum for this article was reported in Vol 120(4) of Journal of Abnormal Psychology (see record 2011-19996-001). In the article there was an error in the affiliation bylines for Rani Elwy and Susan Eisen. Their affiliations should have been listed as Edith Nourse Rogers Memorial Veterans Hospital and Department of Health Policy and Management, Boston University School of Public Health.] Prior research on risk factors for posttraumatic stress symptomatology (PTSS) in war-exposed Veterans has revealed both direct and indirect mechanisms of risk that span predeployment, deployment, and postdeployment timeframes. The aims of the present study were to identify the mechanisms through which previously documented risk factors contribute to PTSS in a national sample of 579 female and male Veterans deployed to Afghanistan for Operation Enduring Freedom (OEF) or to Iraq for Operation Iraqi Freedom (OIF), as well as to examine the extent to which results mirror associations observed among Vietnam Veterans (King, King, Foy, Keane, & Fairbank, 1999). Consistent with conservation of resources (COR) theory (Hobfoll, 1989, 2001), findings indicated that PTSS is accounted for by multiple chains of risk, many originating in predeployment experiences that place Veterans at risk for additional stress exposure, and foretell difficulty accessing resources in the face of subsequent stressors. Importantly, the majority of previously documented mechanisms were replicated in this study, suggesting key pathways through which risk factors may contribute to PTSS across different Veteran populations. Results also revealed a number of novel risk mechanisms for OEF/OIF female Veterans, particularly with respect to the role of deployment family relationships in risk for PTSS. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Gender differences in combat-related stressors and their association with postdeployment mental health in a nationally representative sample of U.S. OEF/OIF veterans.

Though the broader literature suggests that women may be more vulnerable to the effects of trauma exposure, most available studies on combat trauma have relied on samples in which women's combat exposure is limited and analyses that do not directly address gender differences in associations between combat exposure and postdeployment mental health. Female service members' increased exposure to combat in Afghanistan and Iraq provides a unique opportunity to evaluate gender differences in different dimensions of combat-related stress and associated consequence for postdeployment mental health. The current study addressed these research questions in a representative sample of female and male U.S. veterans who had returned from deployment to Afghanistan or Iraq within the previous year. As expected, women reported slightly less exposure than men to most combat-related stressors, but higher exposure to other stressors (i.e., prior life stress, deployment sexual harassment). No gender differences were observed in reports of perceived threat in the war zone. Though it was hypothesized that combat-related stressors would demonstrate stronger negative associations with postdeployment mental health for women, only one of 16 stressor × gender interactions achieved statistical significance and an evaluation of the clinical significance of these interactions revealed that effects were trivial. Results suggest that female Operation Enduring Freedom/Operation Iraqi Freedom service members may be as resilient to combat-related stress as men. Future research is needed to evaluate gender differences in the longer-term effects of combat exposure. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Implementation of Matrix Converter in Wind Energy Conversion System with Modified Control Techniques

Abstract

In this article, different matrix converter (MC) control strategies are comprehensively explained. Further, an ultra-modified space vector modulation (UMSVM) of the MC is proposed. The total harmonic distortion for both output voltage and current is reduced, when the proposed UMSVM technique is applied. Moreover, a modified indirect space vector modulation with feed forward controller (MISVMFC) of the MC is also proposed in order to obtain a fixed output voltage and frequency for different wind speeds. The advantages of the MC are introduced in this article. These advantages include the wide range of the output frequency of MC, which may be greater than the input frequency and the control of both the output voltage magnitude and input displacement factor (IDF). Extensive theoretical and simulation results about conventional and proposed control techniques for the MC are presented. Experimental test bench is constructed and several experimental results are obtained. The experimental results validate the simulation ones.