54 research outputs found

    Simulation of distributed contact in string instruments: A modal expansion approach

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    F21RS SGR No. 3 (Dean\u27s List)

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    A Resolution To Urge and Request LSU to lower the Dean\u27s list requirements from 15 credit hours to 12 credit hour

    Results from Testing Low-Cost, High-Performance Terrestrial Processors for Use in Low-Cost High-Performance Space Missions

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    There has been a significant and exciting increase in the use of microsatellites and cubesats in the past decade. However, it has proved difficult to scale up current cubesat avionics systems to enable larger, longer, more complex missions, and challenging to scale down traditional microsatellites to an affordable price point. The need exists for a system that provides the capability of a microsatellite at a cubesat cost; KISPE Space (“KISPE”) is developing the Next Generation Microsatellite Platform (“NGMP”) to address this need and is releasing the design as an open source resource via the Open Source Satellite Programme (“OSSAT”) A key enabler of developing a robust Next Generation Microsatellite Platform is the identification of a suitable low-cost microprocessor that can be used to form the foundation of an affordable, robust, flexible, performant and autonomous satellite platform avionics system. Space-qualified, long-lifetime, radiation-tolerant (or hardened) processors do exist, however, these technologies are very expensive and tend to deliver poor mission performance compared to the latest terrestrial Commercial-Off-The-Shelf (COTS) components and are not compatible with the limited resources available from cubesats and smallsats. We performed a test campaign to identify one or more commercially available microprocessors that leverage the latest innovations in microprocessor technology and which meet a set of system criteria that make them suitable for use as a microsatellite platform processor for a wide range of missions; from single modest spacecraft, through to proliferated architectures requiring autonomous operations. We are sharing these test results freely with the space community to advance small satellite capabilities and to stimulate the development of the next wave of cost-effective missions, applications and services. Three COTS processors (SAMV71, STM32H7 and SAMA5D3) were downselected for Total Ionising Dose (electron) radiation testing to characterize their performance in a representative space radiation environment, in partnership with the University of Surrey and with the input of OSSA T collaborators. All three processors were deemed to be candidates for further evaluation and derisking: The devices began to fail at 60kRads, 47kRads and in excess of 120kRads respectively

    Synthetic osteogenic extracellular matrix formed by coated silicon dioxide nanosprings

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    <p>Abstract</p> <p>Background</p> <p>The design of biomimetic materials that parallel the morphology and biology of extracellular matrixes is key to the ability to grow functional tissues <it>in vitro </it>and to enhance the integration of biomaterial implants into existing tissues <it>in vivo</it>. Special attention has been put into mimicking the nanostructures of the extracellular matrix of bone, as there is a need to find biomaterials that can enhance the bonding between orthopedic devices and this tissue.</p> <p>Methods</p> <p>We have tested the ability of normal human osteoblasts to propagate and differentiate on silicon dioxide nanosprings, which can be easily grown on practically any surface. In addition, we tested different metals and metal alloys as coats for the nanosprings in tissue culture experiments with bone cells.</p> <p>Results</p> <p>Normal human osteoblasts grown on coated nanosprings exhibited an enhanced rate of propagation, differentiation into bone forming cells and mineralization. While osteoblasts did not attach effectively to bare nanowires grown on glass, these cells propagated successfully on nanosprings coated with titanium oxide and gold. We observed a 270 fold increase in the division rate of osteoblasts when grow on titanium/gold coated nanosprings. This effect was shown to be dependent on the nanosprings, as the coating by themselves did not alter the growth rate of osteoblast. We also observed that titanium/zinc/gold coated nanosprings increased the levels of osteoblast production of alkaline phosphatase seven folds. This result indicates that osteoblasts grown on this metal alloy coated nanosprings are differentiating to mature bone making cells. Consistent with this hypothesis, we showed that osteoblasts grown on the same metal alloy coated nanosprings have an enhanced ability to deposit calcium salt.</p> <p>Conclusion</p> <p>We have established that metal/metal alloy coated silicon dioxide nanosprings can be used as a biomimetic material paralleling the morphology and biology of osteogenic extracellular matrix. The coated nanosprings enhance normal human osteoblasts cellular behaviors needed for improving osseointegration of orthopedic materials. Thus, metal-coated nanosprings represent a novel biomaterial that could be exploited for improving success rates of orthopedic implant procedures.</p

    Detection of different kidney stone types: an ex vivo comparison of ultrashort echo time MRI to reference standard CT

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    BACKGROUND AND PURPOSE: With the development of ultrashort echo time (UTE) sequences, it may now be possible to detect kidney stones by using magnetic resonance imaging (MRI). In this study, kidney stones of varying composition and sizes were imaged using both UTE MRI as well as the reference standard of computed tomography (CT), with different surrounding materials and scan setups. METHODS: One hundred and fourteen kidney stones were inserted into agarose and urine phantoms and imaged both on a dual-energy CT (DECT) scanner using a standard renal stone imaging protocol and on an MRI scanner using the UTE sequence with both head and body surface coils. A subset of the stones representing all composition types and sizes was then inserted into the collecting system of porcine kidneys and imaged in vitro with both CT and MRI. RESULTS: All of the stones were visible on both CT and MRI imaging. DECT was capable of differentiating between uric acid and nonuric acid stones. In MRI imaging, the choice of coil and large field of view (FOV) did not affect stone detection or image quality. The MRI images showed good visualization of the stones' shapes, and the stones' dimensions measured from MRI were in good agreement with the actual values (R(2)=0.886, 0.895, and 0.81 in the agarose phantom, urine phantom, and pig kidneys, respectively). The measured T2 relaxation times ranged from 4.2 to 7.5ms, but did not show significant differences among different stone composition types. CONCLUSIONS: UTE MRI compared favorably with the reference standard CT for imaging stones of different composition types and sizes using body surface coil and large FOV, which suggests potential usefulness of UTE MRI in imaging kidney stones in vivo

    Getting to the Root of Fine Motor Skill Performance in Dentistry: Brain Activity During Dental Tasks in a Virtual Reality Haptic Simulation.

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    BACKGROUND: There is little evidence considering the relationship between movement-specific reinvestment (a dimension of personality which refers to the propensity for individuals to consciously monitor and control their movements) and working memory during motor skill performance. Functional near-infrared spectroscopy (fNIRS) measuring oxyhemoglobin demands in the frontal cortex during performance of virtual reality (VR) psychomotor tasks can be used to examine this research gap. OBJECTIVE: The aim of this study was to determine the potential relationship between the propensity to reinvest and blood flow to the dorsolateral prefrontal cortices of the brain. A secondary aim was to determine the propensity to reinvest and performance during 2 dental tasks carried out using haptic VR simulators. METHODS: We used fNIRS to assess oxygen demands in 24 undergraduate dental students during 2 dental tasks (clinical, nonclinical) on a VR haptic simulator. We used the Movement-Specific Reinvestment Scale questionnaire to assess the students' propensity to reinvest. RESULTS: Students with a high propensity for movement-specific reinvestment displayed significantly greater oxyhemoglobin demands in an area associated with working memory during the nonclinical task (Spearman correlation, rs=.49, P=.03). CONCLUSIONS: This small-scale study suggests that neurophysiological differences are evident between high and low reinvesters during a dental VR task in terms of oxyhemoglobin demands in an area associated with working memory

    Raman identification of olivine grains in fine grained mineral assemblages fired into aerogel

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    NASA’s Stardust mission returned from the comet 81P/Wild2 in 2006 and has yielded a plethora of research looking into the composition and attributes of the comet. The mission itself collected thousands of cometary dust particles as it flew through the coma of the comet at a relative speed of 6.1 km s-1. This work focuses on one of the most abundant minerals in the solar system – olivine. Previous work has shown capture affects on this mineral in similar impacts to that experienced during the Stardust mission. However, the past work looked into effects on isolated mineral grains which would be a rare occurrence in the Solar System. A more accurate representation of this would be to investigate the capture effects on olivine as a constituent of an assemblage of minerals. Accordingly, here we used samples from the NWA 10256 CR2 carbonaceous chondrite meteorite. This natural sample contains fine grains of olivine, and brings additional issues when analysing the olivine due to limited homogeneity. Shifts in the Raman spectra for olivine, enstatite and hematite were observed after capture due to shock effects. However, this work suggests that olivine may well experience a different shock effect during capture when part of a mineral assemblage as distinct from that experienced by single grains

    Developing the Enquiring Student and Enhancing the Research-Teaching Interface: Student-led Pedagogical Research and Educational Initiatives in Enquiry Based Learning

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    This paper describes the progress of a project running at the University of Glasgow to develop elements of Enquiry Based Learning (EBL) in undergraduate degree courses across a range of disciplines. It focuses on the second part of the project but an overview of the first part is also given. During phase 1 of the project, in the summer of 2007, seven undergraduate students spent four weeks working together exploring enquiry based learning (EBL) in the institution’s central, educational development unit. This phase was approached as an EBL exercise itself; the student groups were given full responsibility for the process with the proviso that by the end of this phase they would have developed a guide for staff and students about EBL. The second phase of the project continues throughout the academic year 07/08. Here, each student worked alongside a member of staff from their department of study to develop discipline specific EBL activities taking a research-informed approach to this development. All pairings were charged with introducing EBL such that no major course change procedures had to be followed; this hopefully ensured the sustainability of such adjustments. Staff and students involved in the project represent dentistry, chemistry, biology, theology, law and psychology and the courses under development range from large first year classes to small honours level courses. An overview of the range of enquiry-based learning developments within the courses will be described

    Developing the Enquiring Student and Enhancing the Research-Teaching Interface: Student-led Pedagogical Research and Educational Initiatives in Enquiry Based Learning

    Get PDF
    This paper describes the progress of a project running at the University of Glasgow to develop elements of Enquiry Based Learning (EBL) in undergraduate degree courses across a range of disciplines. It focuses on the second part of the project but an overview of the first part is also given. During phase 1 of the project, in the summer of 2007, seven undergraduate students spent four weeks working together exploring enquiry based learning (EBL) in the institution’s central, educational development unit. This phase was approached as an EBL exercise itself; the student groups were given full responsibility for the process with the proviso that by the end of this phase they would have developed a guide for staff and students about EBL. The second phase of the project continues throughout the academic year 07/08. Here, each student worked alongside a member of staff from their department of study to develop discipline specific EBL activities taking a research-informed approach to this development. All pairings were charged with introducing EBL such that no major course change procedures had to be followed; this hopefully ensured the sustainability of such adjustments. Staff and students involved in the project represent dentistry, chemistry, biology, theology, law and psychology and the courses under development range from large first year classes to small honours level courses. An overview of the range of enquiry-based learning developments within the courses will be described
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