1,621 research outputs found

    Track train dynamics analysis and test program: Methodology development for the derailment safety analysis of six-axle locomotives

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    The operational safety of six axle locomotives is analyzed. A locomotive model with corresponding data on suspension characteristics, a method of track defect characterization, and a method of characterizing operational safety are used. A user oriented software package was developed as part of the methodology and was used to study the effect (on operational safety) of various locomotive parameters and operational conditions such as speed, tractive effort, and track curvature. The operational safety of three different locomotive designs was investigated

    Nonequilibrium static growing length scales in supercooled liquids on approaching the glass transition

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    The small wavenumber kk behavior of the structure factor S(k)S(k) of overcompressed amorphous hard-sphere configurations was previously studied for a wide range of densities up to the maximally random jammed state, which can be viewed as a prototypical glassy state [A. Hopkins, F. H. Stillinger and S. Torquato, Phys. Rev. E, 86, 021505 (2012)]. It was found that a precursor to the glassy jammed state was evident long before the jamming density was reached as measured by a growing nonequilibrium length scale extracted from the volume integral of the direct correlation function c(r)c(r), which becomes long-ranged as the critical jammed state is reached. The present study extends that work by investigating via computer simulations two different atomic models: the single-component Z2 Dzugutov potential in three dimensions and the binary-mixture Kob-Andersen potential in two dimensions. Consistent with the aforementioned hard-sphere study, we demonstrate that for both models a signature of the glass transition is apparent well before the transition temperature is reached as measured by the length scale determined from from the volume integral of the direct correlation function in the single-component case and a generalized direct correlation function in the binary-mixture case. The latter quantity is obtained from a generalized Orstein-Zernike integral equation for a certain decoration of the atomic point configuration. We also show that these growing length scales, which are a consequence of the long-range nature of the direct correlation functions, are intrinsically nonequilibrium in nature as determined by an index XX that is a measure of deviation from thermal equilibrium. It is also demonstrated that this nonequilibrium index, which increases upon supercooling, is correlated with a characteristic relaxation time scale.Comment: 26 pages, 14 figure

    Imp d&e feasibility study

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    Launching of Interplanetary Monitoring Platform spacecraft into lunar orbi

    Scaffolding for assessment success: using gradual release of responsibility to support resident transition to competency-based medical education

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    In competency-based medical education (CBME), assessment is learner-driven; learners may fail to progress if assessments are not completed. The General Internal Medicine (GIM) program at Queen’s University uses an educational technique known as scaffolding in its assessment strategy. The program applies this technique to coordinate early assessments with specific scheduled learning experiences and gradually releases the responsibility for assessment initiation to residents. Although outcomes of this innovation are still under investigation, we feel it has been valuable in supporting resident assessment capture and timely progression through stages of training.  Other residency training programs could easily implement this technique to support the transition to Competency by Design

    In vitro Accelerated Aging of Composites and a Sealant

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    The in vitro accelerated aging of conventional and microfilled composite restorative materials and a sealant was studied. Volume loss/surface area ranged from 2.0 to 7.3 x 10-3 mm3/mm2 after 900 h of aging. Surface morphology changed more dramatically for the conventional composites than for the other materials. Changes in surface chemistry as measured by FTIR-ATR were observed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67091/2/10.1177_00220345810600090701.pd

    Using Focus Groups to Develop a Bone Health Curriculum for After-school Programs

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    INTRODUCTION: Childhood behaviors influence peak bone mass and osteoporosis risk in later life. The after-school environment provides an opportunity to enrich a child’s learning and experience. Our objective was to gain a better understanding of the knowledge of, attitudes and beliefs about, and barriers to achieving bone health among children, parents, and after-school program leaders from low-income, ethnically diverse communities. Findings led to the development, implementation, and evaluation of a bone health curriculum in the after-school setting. METHODS: Eight focus groups were conducted in three representative communities. Focus group participants included children aged six to eight years, parents of children aged six to eight, and after-school program staff. Transcripts and written notes from each session were reviewed and common themes were identified within each group. RESULTS: Most adults had some understanding of osteoporosis, but did not recognize that childhood behaviors had a role in developing the disease. Program leaders raised concerns about their ability to implement a health program and recommended a flexible format. Parents and program leaders recognized the importance of maintaining a fun atmosphere. CONCLUSION: It is feasible to create a curriculum for a bone health program that meets the unique needs and interests of children and program leaders in the after-school setting. Addressing the needs, interests, and common barriers of the target population is an essential first step in curriculum development
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