7,792 research outputs found

    Magnetomechanical damping by polycrystalline TbDy

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    Vibration damping in polycrystalline TbDy alloys was studied at cryogenic temperatures. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations at 77 K. Some textured TbDy materials demonstrated 22.6% energy dissipation in mechanical measurements at low frequency (0.01 Hz) and a mean logarithmic decrement of 0.23 at a higher frequency (25 kHz). Ultrasonic velocities of longitudinal and shear elastic waves were measured on single and polycrystalline TbDy; little variation in ultrasonic velocities was found even for samples with large variation in crystallographic texture and magnetomechanical properties

    Magnetomechanical effects in textured polycrystalline Tb76Dy24

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    Uniaxial stress-strain measurements were performed on polycrystalline Tb76Dy24 alloys which exhibit "giant magnetostriction" at cryogenic temperatures. The Young's moduli were reduced by up to a factor of five at 77 K, in comparison to their values at 300 K. We attribute this reduction to a mechanical compliance from domain rotation. Large mechanical hysteresis is also found in nominally elastic stress-strain curves measured below the Curie temperature. Hysteretic curves from 0 to 25 MPa demonstrate up to 19% dissipation of the applied mechanical energy. The anisotropy of thermal expansion was also measured and used as a parameter for the degree of crystallographic texture. This anisotropy was correlated to bulk magnetostriction and to mechanical hysteresis

    The Montage Image Mosaic Service: Custom Image Mosaics On-Demand

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    The Montage software suite has proven extremely useful as a general engine for reprojecting, background matching, and mosaicking astronomical image data from a wide variety of sources. The processing algorithms support all common World Coordinate System (WCS) projections and have been shown to be both astrometrically accurate and flux conserving. The background ‘matching’ algorithm does not remove background flux but rather finds the best compromise background based on all the input and matches the individual images to that. The Infrared Science Archive (IRSA), part of the Infrared Processing and Analysis Center (IPAC) at Caltech, has now wrapped the Montage software as a CGI service and provided a compute and request management infrastructure capable of producing approximately 2 TBytes / day of image mosaic output (e.g. from 2MASS and SDSS data). Besides the basic Montage engine, this service makes use of a 16-node LINUX cluster (dual processor, dual core) and the ROME request management software developed by the National Virtual Observatory (NVO). ROME uses EJB/database technology to manage user requests, queue processing and load balance between users, and managing job monitoring and user notification. The Montage service will be extended to process userdefined data collections, including private data uploads

    Is a Musical Intervention Effective In the Reduction of Needle Related Procedural Pain in Children?

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    OBJECTIVE:Trypanophobia, or the fear of needles and needle pain is a very common occurrence in children, one that can have significant impacts into adulthood and on an individual’s lifelong healthcare. The objective of this systematic review is to determine whether or not a musical intervention is effective in the reduction of needle-related procedural pain in children. The author searched OVID Medline and Cochrane databases for peer-reviewed articles and systematic reviews addressing the topic, published in English after 1996. Three randomized controlled trials were selected on the basis of their being POEM’s and not included in previous systematic reviews, the results of which were used to determine the effects of a musical intervention on childrens’ pain, anxiety, and several physiologic markers during needle-related procedures. Each of these three trials measured responses to the musical interventions using visual analog or FACES scales, and results were statistically analyzed, having varying levels of significance in the reduction of pain and distress of the children. Review of these results indicates that when available, a musical intervention is effective in the reduction of needle-related procedural pain in children undergoing medical procedures

    Old Bulloch Meeting Places

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    Student papers on the rise and decline of eight Bulloch County communities, including Parish, Pulaski, Jimps, Colfax Station, Clito, Leefield, Emit, and Mill Ray.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1025/thumbnail.jp

    A Cost-Benefit Study of Doing Astrophysics On The Cloud: Production of Image Mosaics

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    Utility grids such as the Amazon EC2 and Amazon S3 clouds offer computational and storage resources that can be used on-demand for a fee by compute- and data-intensive applications. The cost of running an application on such a cloud depends on the compute, storage and communication resources it will provision and consume. Different execution plans of the same application may result in significantly different costs. We studied via simulation the cost performance trade-offs of different execution and resource provisioning plans by creating, under the Amazon cloud fee structure, mosaics with the Montage image mosaic engine, a widely used data- and compute-intensive application. Specifically, we studied the cost of building mosaics of 2MASS data that have sizes of 1, 2 and 4 square degrees, and a 2MASS all-sky mosaic. These are examples of mosaics commonly generated by astronomers. We also study these trade-offs in the context of the storage and communication fees of Amazon S3 when used for long-term application data archiving. Our results show that by provisioning the right amount of storage and compute resources cost can be significantly reduced with no significant impact on application performance

    A review of the immunomodulating components of maternal breast milk and protection against necrotizing enterocolitis

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    Breast milk contains immunomodulating components that are beneficial to newborns during maturation of their immune system. Human breast milk composition is influenced by an infant\u27s gestational and chronological age, lactation stage, and the mother and infant\u27s health status. Major immunologic components in human milk, such as secretory immunoglobulin A (IgA) and growth factors, have a known role in regulating gut barrier integrity and microbial colonization, which therefore protect against the development of a life-threatening gastrointestinal illness affecting newborn infants called necrotizing enterocolitis (NEC). Breast milk is a known protective factor in the prevention of NEC when compared with feeding with commercial formula. Breast milk supplements infants with human milk oligosaccharides, leukocytes, cytokines, nitric oxide, and growth factors that attenuate inflammatory responses and provide immunological defenses to reduce the incidence of NEC. This article aims to review the variety of immunomodulating components in breast milk that protect the infant from the development of NEC

    Magnetostriction of single crystal and polycrystalline Tb0.60Dy0.40 at cryogenic temperatures

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    At cryogenic temperatures, single crystals of TbDy alloys exhibit giant magnetostrictions of nearly 9000 ppm, making these materials promising for engineering service in cryogenic actuators, valves, and positioners. The preparation of single crystals is difficult and costly. Preliminary results on the magnetostriction of textured polycrystalline materials are presented here. For instance, polycrystalline Tb0.60Dy0.40, plane-rolled (one direction of applied stress) to induce crystallographic texture, has shown magnetostrictions at 77 K of 3000 ppm for an applied field of 4.5 kOe and an applied load of 23 MPa, or 48% that of a single crystal under similar conditions. Comparisons are presented between the magnetostrictive response of plane- and form-rolled (two orthogonal directions of applied stress) polycrystalline Tb0.60Dy0.40 at 10 and 77 K. It is reported that at 10 K plane-rolled Tb0.60Dy0.40 exhibits 1600 ppm magnetostriction at an applied field of 4.4 kOe with a minimal applied load of 0.28 MPa. An observed restoration of the initial unstrained state may be a useful feature of polycrystalline materials for engineering service. Finally it is reported that thermal expansion measurements provide a measure of crystallographic texture for comparison with the magnetostriction

    In Search of the Irish Hill Cemetery in Bulloch County

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    A project by Susan Moody and Dan Good to find and document the Irish cemetery of Bulloch County lore. This paper discusses the findings of the project, explains the methodology used in data collection, and reviews some of the history associated with Irish immigration into Georgia and the Bulloch County area.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1018/thumbnail.jp
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