518 research outputs found

    Sol-Gel Prepared Nanoscopic Metal Fluorides - a New Class of Tunable Acid-Base Catalysts

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    In this article, the high potential of the fluorolytic sol-gel process to synthesise nanoscopic metal fluorides with different acid-base properties is shown. These nanoscopic materials exhibit high potential to be used as heterogeneous catalysts due to their high surface areas and their tunable surface properties. Thus, for each specific reaction the required surface properties of the catalysts can be ”adjusted” to achieve a high yield and selectivity of the desired product. As a consequence, a greener method of chemical production can be accomplished. Moreover the cheap and easy synthesis of the catalysts using basic chemicals makes them not only interesting for fundamental research but provides an easy transformation to industrial applications

    The influences of financial self-efficacy and financial socialization on college students’ financial stress and coping

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    Doctor of PhilosophyDepartment of Human Ecology-Personal Financial PlanningStuart HeckmanMaurice M. MacDonaldThere were 19.8 million college students in the U.S. in the fall of 2017 (NCES, 2017). These students face many challenges and opportunities including new social networks, enhanced academic pressures, new living arrangement and new financial responsibilities. Many of these students have had positive role models who have socialized them through discussion and example (Shim, Barber, Card, Xiao, & Serido, 2010). These role models may have instilled positive self-efficacy in these students as well helping to prepare the students for the many challenges and opportunities in college. Some students have not had those role models. This research seeks to understand the impact of positive socialization and self-efficacy on students’ feelings of financial stress and then on their choices of how to cope with that stress. The financial challenges of paying for college are well publicized with 44.2 million Americans currently owing over $1.48 trillion in student loan debt (NCES, 2017). In this study, the impact of these financial challenges is viewed through the lens of the Transactional Model of Stress and Coping Theory which proposes that stress is an individual perception influenced by that individual’s sense of threat, vulnerability, and ability to cope (Lazarus & Folkman, 1984). There are two sets of empirical models; the first examines the influences in the appraisal process on perceptions of financial stress using OLS regression with the second empirical model examining the influences on their coping choices using logistic regression. Both models control for influences on stress and coping choices including demographic, socio-economic and academic factors. The results inform how financial self-efficacy and financial socialization influence financial stress as they suggest the importance of enabling financial self-efficacy by parents, educators and other leaders of children

    Particle-in-cell Simulation Concerning Heat-flux Mitigation Using Electromagnetic Fields

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    The Particle-in-Cell (PIC) method was used to study heat flux mitigation experiments with argon. In the experiment it was shown that a magnetic field allows to reduce the heat flux towards a target. PIC is well-suited for plasma simulation, giving the chance to get a better basic understanding of the underlying physics. The simulation demonstrates the importance of a self-consistent neutral-plasma description to understand the effect of heat flux reduction

    Solutioin of Poisson's Equation in Electrostatic Particle-on-cell Simulation

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    In electrostatic Particle-in-Cell simulations of the HEMP-DM3a ion thruster the role of different solution strategies for Poisson?s equation was investigated. The direct solution method of LU decomposition is compared to a stationary iterative method, the successive over-relaxation solver. Results and runtime of solvers were compared, and an outlook on further improvements and developments is presented

    Influence of Electron Sources on the Near-field Plume in a Multistage Plasma Thruster

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    n order to obtain a better understanding of the near-field plume of a multistage plasma thruster, the influence of an external electron source is investigated by Particle-In-Cell simulations. The variation of the source position showed a strong influence of the magnetic field configuration on the electron distribution and therefore on the plume plasma. In the second part of this work, higher energetic electrons were injected in order to model collision-induced diffusion in the plume. This broadens the electron distribution, which leads to a more pronounced divergence angle in the angular ion distribution

    What is Wrong with Water Barometers?

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    Every student who studies atmospheric pressure in physics or chemistry learns the principles behind the construction of barometers. Cistern barometers, such as those found in most laboratories, consist of a long glass tube containing an inverted column of liquid having an open end in a cistern of the liquid. Students learn that the column of liquid is supported by air pressure and is equal in weight to a column of air of the same diameter

    Moderate physical activity may prevent cartilage loss in women with knee osteoarthritis : data from the Osteoarthritis Initiative

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    All authors have completed the ICMJE uniform disclosure form at http://www.icmje.org/coi_disclosure.pdf and declare: data acquisition in this study was funded by the Osteoarthritis Initiative, a public–private partnership comprised of five contracts (N01-AR-2-2258; N01-AR-2-2259;N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the National Institutes of Health, a branch of the Department of Health and Human Services, and conducted by the Osteoarthritis Initiative study Investigators. Private funding partners of the OAI include Merck Research Laboratories, Novartis Pharmaceuticals Corporation, GlaxoSmithKline, and Pfizer, Inc. Private sector funding for the Osteoarthritis Initiative is managed by the Foundation for the National Institutes of Health. The image analysis in this study was partly funded by the FNIH OA Biomarkers Consortium, with grants, direct and in -kind contributions, provided by: AbbVie; Amgen Inc.; Arthritis Foundation; Bioiberica S.A.; DePuy Mitek, Inc.; Flexion Therapeutics, Inc.; GlaxoSmithKline; Merck KGaA; Rottapharm | Madaus; Sanofi; and Stryker. Other parts of funding were provided by a direct grant from Merck KGaA, by a contract with the University of Pittsburgh (Pivotal OAI MRI Analyses [POMA]: NIH/NHLBI Contract No. HHSN2682010000 21C), by a vendor contract from the OAI coordinating center at University of California, San Francisco (N01-AR-2-2258), and by an ancillary study to the OAI held by the Division of Rheumatology, Feinberg School of Medicine, Northwestern University (R01 AR52918). This research has also received funding from the European Union Seventh Framework Programme (FP7-PEOPLE-2013-ITN; KNEEMO) under grant agreement number 607510. AGC is supported by a National Health and Medical Research Council (NHMRC) of Australia Early Career Fellowship (Neil Hamilton Fairley Clinical Fellowship No.1121173). The sponsors were not involved in the design and conduct of this particular study, in the analysis and interpretation of the data, and in the preparation, review, or approval of the manuscript.Peer reviewedPostprin

    Mitigation of Anisotropic Fatigue in Nickel Alloy 718 Manufactured via Selective Laser Melting

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    The tension-tension fatigue behavior of heat treated selective laser melted (SLM) nickel alloy 718 (IN718) tensile specimens was tested and compared to as-built specimens. In addition to the industry standard IN718 heat treatment, a modified heat treatment was developed and tested in order to mitigate the anisotropic mechanical properties inherent to SLM materials. Electron backscatter diffraction verified that the modified heat treatment significantly affected the microstructure in all build planes. Three different print orientations were studied to determine their effect on the fatigue behavior. Both heat treatments improved the fatigue life of the specimens, although neither surpassed the fatigue life of wrought specimens. The modified heat treatment reduced the effect of the print orientation on the fatigue life. Surface roughness estimates made by laser scanning microscopy revealed a threshold between roughness controlled fatigue life behavior and print orientation fatigue life dependence. Fracture surface analysis indicated that the print orientation was the greatest factor that influences crack initiation and propagation

    Efecto del consumo de mate sobre el perfil lipídico en pacientes hipercolesterolémicos

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    El consumo diario de mate, en dosis de 50g o 100g, produce un descenso en CT y CLDL, mejorando el índice aterogénico en individuos hipercolesterolémicos
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