1,516 research outputs found

    Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model

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    This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5 km/s using a 40-gram aluminum alloy sphere, whereas the second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-gram aluminum alloy sphere by two-stage light gas gun in Kyushu Institute of Technology. To date, approximately 1,500 fragments from each impact test have been collected for detailed analysis. Each piece was analyzed based on the method used in the NASA Standard Breakup Model 2000 revision. The detailed analysis will conclude: 1) the similarity in mass distribution of fragments between low and hyper-velocity impacts encourages the development of a general-purpose distribution model applicable for a wide impact velocity range, and 2) the difference in area-to-mass ratio distribution between the impact experiments and the NASA standard breakup model suggests to describe the area-to-mass ratio by a bi-normal distribution

    Determination of Pinning Parameters in Flux Creep-Flow Model for E-J characteristics of High Temperature Superconductors by using Differential Evolution

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    The pinning parameters such as strength of pinning force, temperature dependence of pinning force and so on using in flux creep-flow model to explain electric field vs current density (E-J) characteristics were determined by Differential Evolution (DE). DE is one of the methods in Evolutionary Computation (EC) to find an optimization of a problem. First, a model data of E-J characteristics in which the pinning parameters were given was prepared, and it was confirmed that DE can find the given pinning parameters from the model data. Then, DE and mesh method were used to determine the pinning parameters in experimental E-J characteristics of GdBa2CuO7-δ high temperature superconductor. In mesh method, the all combinations of pinning parameters with constant interval for each parameter are calculated, and best set of pinning parameters is selected. It was found that DE shows better performance than mesh method in terms of calculation time and accuracy for determining pinning parameters

    Expression transmission using exaggerated animation for Elfoid

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    We propose an expression transmission system using a cellular-phone-type teleoperated robot called Elfoid. Elfoid has a soft exterior that provides the look and feel of human skin, and is designed to transmit the speaker's presence to their communication partner using a camera and microphone.To transmit the speaker's presence, Elfoid sends not only the voice of the speaker but also the facial expression captured by the camera. In this research, facial expressions are recognized using a machine learning technique. Elfoid cannot, however, display facial expressions because of its compactness and a lack of sufficiently small actuator motors. To overcome this problem, facial expressions are displayed using Elfoid's head-mounted mobile projector. In an experiment, we built a prototype system and experimentally evaluated its subjective usability

    Inclusive Education is Power: Revising Sexual Health Education for People with Disabilities

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    For people with disabilities in the United States, comprehensive sexual health education is not always available. There are a number of reasons for the lack of comprehensive sexual health education, including excessive censorship and curriculum that is not representative of people with disabilities. Sexual health education and disability are both topics that have several preconceived notions attached to them, yet there is a dearth in resources that could provide accurate information to those both with and without disabilities. These preconceived notions that have been associated with these identity labels lead to negative health outcomes for people with disabilities such as increased reports of abuse and higher rates of female sterilization. Without a revision of the way the U.S. currently addressed sexual health education, people with disabilities will continue to suffer these consequences at higher rates than their non-disabled counterparts. This paper will discuss how comprehensive sexual health education for people with disabilities is lacking and provide recommendations as to how this gap in education can be remedied. Teaching people through comprehensive sexual health education allows people to advocate for their personal health with an informed mindset, regardless of ability status

    Cyclic Torsional Shear Tests to Obtain Dynamic Soil Properties for Seismic Design of Road Embankments

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    Many road embankments have suffered damage during past earthquakes. The authors took soil samples from several embankments and conducted laboratory tests to demonstrate the mechanism of the damages and study appropriate seismic design methods. In the laboratory tests, cyclic torsional shear tests were carried out to obtain undrained cyclic strength, excess pore water pressure and shear modulus after cyclic loading of embankment soils. Test results showed a unique relationship between Plasticity Index and undrained cyclic strength is existed. Relationship between excess pore water pressure ratio and safety factor against liquefaction is also influenced by Plasticity Index. Then appropriate seismic design methods by applying these test results are discussed

    Value of MR neurography for evaluating extraspinal neuropathic leg pain: a pictorial essay

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    Journal ArticleSummary: Fifteen patients with neuropathic leg pain referable to the lumbosacral plexus or sciatic nerve underwent high-resolution MR neurography. Thirteen of the patients also underwent routine MR imaging of the lumbar segments of the spinal cord before undergoing MR neurography. Using phased-array surface coils, we performed MR neurography with T1-weighted spin-echo and fat-saturated T2-weighted fast spin-echo or fast spin-echo inversion recovery sequences, which included coronal, oblique sagittal, and/or axial views. The lumbosacral plexus and/or sciatic nerve were identified using anatomic location, fascicular morphology, and signal intensity as discriminatory criteria. None of the routine MR imaging studies of the lumbar segments of the spinal cord established the cause of the reported symptoms. Conversely, MR neurography showed a causal abnormality accounting for the clinical findings in all 15 cases. Detected anatomic abnormalities included fibrous entrapment, muscular entrapment, vascular compression, posttraumatic injury, ischemic neuropathy, neoplastic infiltration, granulomatous infiltration, neural sheath tumor, postradiation scar tissue, and hypertrophic neuropathy
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