351 research outputs found

    Synthesis of surface composites using friction stir processing

    Get PDF
    Composite materials have an edge over monolithic materials due to higher strength/stiffness - to - density ratios, improved fatigue and wear resistance and better high temperature properties. Surface composites provide improved tribological properties such as wear resistance, friction coefficient and corrosion resistance. Friction stir processing (FSP) which originated from friction stir welding (FSW - a method for joining aluminum alloys) is a solid state technique to modify the microstructure of the alloys. During FSP the frictional heat generated at the tool - work piece interface plasticizes the material allowing it to flow around the pin. The combined effect of the plastic deformation and the generated heat leads to grain refinement in the alloys. In the present work, effort has been made to expand the scope of FSP as a novel method for the synthesis of surface composites. Different ways for incorporation of SiC particles into Al1100 alloy were explored and compared with each other. The response of the flow of the powder in the substrate during FSP has been studied for different processing features. The effects of various parameters and methodology on the incorporation and distribution of SiC particles in the nugget, the microstructure and mechanical properties of the composite layer were studied --Abstract, page iv

    Effects of pioglitazone on cardiovascular function in type I and type II diabetes mellitus

    Get PDF

    Uncovering the Past: My Family History

    Get PDF
    Genealogy is the study of families, family histories, and tracing of lineages. Information can be discovered through oral interviews, historical records, and genetic analyses. The purpose of the narrative was to use genealogical data to create my own family history. Using 23andme I was able to trace the ancestors of my maternal haplogroup as they moved out of Africa approximately 60,000 years ago. My most recent maternal haplogroup is M3a2. Family interviews were also conducted to acquire information on my genealogical tree, as well as family histories and photos. I also used genealogical databases, including myheritage.com, in order to build my family tree

    A Fundamental Study of Nanostructured Si Anodes for Lithium Ion Batteries

    Get PDF
    Lithium-ion (Li-ion) batteries have emerged as the flagship, ubiquitous energy storage systems for portable / stationary consumer electronic devices such as video cameras, laptops, mobile phones including the plug-in hybrid as well as in the current models of all electric vehicles (EVs). Despite the commercialization of the first prototype Li-ion battery in 1990 by Sony, commercial Li-ion battery systems currently still employ graphite/carbon having a theoretical capacity of ~372 mAh/g as the anode system. Silicon exhibits a theoretical capacity of ~4200 mAh/g and is explored as a promising anode to replace graphite in LIBs. However, silicon undergoes huge volume expansion (>300%) during lithium alloying / de-alloying resulting, in tremendous crystallographic related phase induced stresses. As a result of these stresses, there is pulverization of the active material in the electrodes resulting in loss of electronic contact with the substrate/current collector resulting in drastic and rapid reduction in capacity and subsequently, the failure of the battery. In this work, different synthesis approaches (electrodeposition, electroless plating, hydrothermal synthesis, chemical vapor deposition, high energy mechanical milling) for generating nanoscale Si and/or Si composite nanostructures, such as (1) silicon-carbon core-shell (C@Si@C) hollow nanotubes, (2) silicon nanorods and silicon nanoflakes, (3) electrodeposition of silicon thin films and (4) Si/VACNTs directly grown on Cu serving as binder-less system, are discussed. Their electrochemical behavior has been analyzed and correlated to the synthesis process, ensuing structural changes, related structural and microstructural property, degradation mechanism and finally their performance. The Si anodes were characterized for their structure, microstructure and electrochemical performance (first cycle irreversible loss, specific charge – discharge capacities, fade rate) in Li/Li+ system. Their behavior was correlated to morphology of nanostructures before and after electrochemical cycling, and process parameters employed during the synthesis process. X-Ray diffraction, Raman spectroscopy, SEM/TEM, BET analysis and XPS have been used to characterize the crystallographic structure and composition of these nanostructures before and after electrochemical cycling to confirm the evolution, phase and morphological stability of these nanostructures. Subsequently, effort has been made to analyze and study the electrochemical response in full cell system using LiNMC111 at critical loadings using CC-CV mode of testing

    GSU Scheduling System

    Get PDF
    The main agenda of this project is scheduling student project sessions for a particular semester. In this system we going to develop a web based application where students who are been registered for this particular section can directly select their slot and time when they want to give Presentation of their project and also they can directly submit their abstract online and also they can get updates as a messages and e-mails which are been send to their personal contact numbers and email address regarding their project and where as advisor can add the students and manage the schedule of the project selected by the student

    No Difference in Stress Level Based on Physical Activity During the COVID-19 Pandemic Among Parents of School-Aged Children

    Get PDF
    Stress levels among children and parents have been heightened during the COVID-19 pandemic, especially with related changes in school structure. Regular physical activity (PA) represents a way to decrease stress levels and improve overall mood. Thus, regular PA is even more important during this period of prolonged stress as the pandemic continues to affect communities. PURPOSE: The purpose of this study was to examine differences in stress levels among parents of school-aged children during the COVID-19 pandemic based upon physical activity patterns. METHODS: Parents (n = 115, 91% female, 91% White) of school-aged children in the United States participated in surveys regarding their stress levels and physical activity. Stress levels were determined by the Perceived Stress Scale and dichotomized into Low Stress or Moderate/High Stress. To determine level of physical activity, participants also completed the Recreational and Sedentary portions of the WHO\u27s Global Physical Activity Questionnaire (7 questions). They were then dichotomized into “met” or “did not meet” World Health Organization’s recommendations for weekly physical activity (150 minutes moderate PA (MPA), 70 minutes of vigorous PA (VPA), or 600 MET*minutes). Perceived stress levels were analyzed using a chi-square test to determine any differences between the two groups based upon each WHO recommendation for physical activity (MPA, VPA, MET*minutes). RESULTS: A total of 47% of parents perceived themselves as having low stress while 53% reported moderate/high stress. A majority of parents did not meet WHO PA recommendations for weekly MPA (63%) nor VPA (64%) but did meet recommendations for weekly MET*min (59%). All chi-square tests were non-significant (MPA: Χ2 = .246, df = 1, p = .620; VPA: Χ2 = 3.422, df = 1, p = .064; MET*min: Χ2 = 1.361, df = 1, p = .243). CONCLUSION: The present study demonstrates that there was no significant difference in perceived stress levels based upon physical activity among parents of school-aged children during the COVID-19 pandemic, regardless of intensity of the physical activity. Even with the known positive benefits of PA to decrease stress, PA was not significantly associated with reduced stress levels among parents of school-aged youth. This finding could reflect stress exceeding normal levels due to the novel and unknown nature of the pandemic. It is also possible that PA did have a positive impact on stress levels but was too small to significantly counteract the abnormal increase in perceived stress. However, PA is still important for adults, including parents of school-aged youth, during the COVID-19 pandemic due to the numerous other health benefits it can provide beyond reducing stress levels

    Acute binge drinking increases serum endotoxin and bacterial DNA levels in healthy individuals

    Get PDF
    Binge drinking, the most common form of alcohol consumption, is associated with increased mortality and morbidity; yet, its biological consequences are poorly defined. Previous studies demonstrated that chronic alcohol use results in increased gut permeability and increased serum endotoxin levels that contribute to many of the biological effects of chronic alcohol, including alcoholic liver disease. In this study, we evaluated the effects of acute binge drinking in healthy adults on serum endotoxin levels. We found that acute alcohol binge resulted in a rapid increase in serum endotoxin and 16S rDNA, a marker of bacterial translocation from the gut. Compared to men, women had higher blood alcohol and circulating endotoxin levels. In addition, alcohol binge caused a prolonged increase in acute phase protein levels in the systemic circulation. The biological significance of the in vivo endotoxin elevation was underscored by increased levels of inflammatory cytokines, TNFalpha and IL-6, and chemokine, MCP-1, measured in total blood after in vitro lipopolysaccharide stimulation. Our findings indicate that even a single alcohol binge results in increased serum endotoxin levels likely due to translocation of gut bacterial products and disturbs innate immune responses that can contribute to the deleterious effects of binge drinking
    • …
    corecore