1,003 research outputs found

    3D Parametric Hand to Improve Prosthetic Hand Functionality

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    The use of prosthetics can significantly enhance an individual’s standard of living, not only offering functional advantages but psychological advantages as well. Unfortunately for children with upper limb reduction, options are limited and rejection rates are high due to a multitude of reasons including discomfort and poor functionality. This study proposes a new parametric 3D design model (Parametric Hand) with an adjustable thumb that can be easily manipulated to the uniqueness of an individual. The Parametric Hand was evaluated, both qualitatively and quantitatively, against the Flexy-Hand 2, a commonly used prosthetic hand. The results showed insignificant differences in all testing except when grasping larger objects where the Parametric Hand excelled over the Flexy-Hand 2. This research concludes that the proposed design can perform better than Flexy-Hand 2 while providing the ability to customization fitting for a specific use

    A new dataset and empirical relationships between magnitude/intensity and epicentral distance for liquefaction in central-eastern Sicily

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    Strong earthquakes can trigger several phenomena inducing soil deformation, such as liquefaction, ground fracturing and landslides, which can often cause more damage than the seismic shaking itself. A research performed on numerous historical accounts reporting descriptions of seismogeological effects in central-eastern Sicily, allowed the authors to update the previous liquefaction datasets. 75 liquefaction-induced phenomena observed in 26 sites, triggered by 14 earthquakes, have been used to define relationships between intensity/magnitude values and epicentral distance from the liquefied sites. The proposed upper bound-curves, at regional scale for central- eastern Sicily, are realized by using the updating liquefaction dataset and also the new CPTI04 Italian earthquake parametric catalogue. These relationships can be useful in hazard assessment to evaluate the minimum energy of an earthquake inducing liquefactions

    The Crab pulsar light curve in the soft gamma ray range: FIGARO II results

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    The FIGARO II experiment (a large area, balloon borne, crystal scintillator detector working from 0.15 to 4.3 MeV) observed the Crab pulsar on 1990 Jul. 9 for about seven hours. The study of the pulse profile confirms some structures detected with a low significance during the shorter observation of 1986, and adds new important elements to the picture. In particular, between the two main peaks, two secondary peaks appear centered at phase values 0.1 and 0.3, in the energy range 0.38 to 0.49 MeV; in the same energy range, a spectral feature at 0.44 MeV, interpreted as a redshifted positron annihilation line, was observed during the same balloon flight in the phase interval including the second main peak and the neighboring secondary peak. If the phase interval considered is extended to include also the other secondary peak, the significance of the spectral line appears to increase

    Negative Equity and Foreclosure: Theory and Evidence

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    Millions of Americans have negative housing equity, meaning that the outstanding balance on their mortgage exceeds their home's current market value. Our data show that the overwhelming majority of these households will not lose their homes. Our finding is consistent with historical evidence: we examine more than 100,000 homeowners in Massachusetts who had negative equity during the early 1990s and find that fewer than 10 percent of these owners eventually lost their home to foreclosure. This result is also, contrary to popular belief, completely consistent with economic theory, which predicts that from the borrower's perspective, negative equity is a necessary but not a sufficient condition for foreclosure. Our findings imply that lenders and policymakers face a serious information problem in trying to help borrowers with negative equity, because it is difficult to determine which borrowers actually require help in order to prevent the loss of their homes to foreclosure

    Numerical modeling of bifacial PV string performance: Perimeter effect and influence of uniaxial solar trackers

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    The bifacial photovoltaic (PV) systems have recently met large interest. The performance of such systems heavily depends on the installation conditions and, in particular, on the albedo radiation collected by the module rear side. Therefore, it is of crucial importance to have an accurate performance model. To date, in the scientific literature, numerous models have been proposed and experimental data collected to study and optimize bifacial PV system performance. Currently, 3D and 2D models of bifacial PV devices exist. Though the former are more mathematically complex, they can lead to more accurate results, since they generally allow to fully consider the main aspects influencing a bifacial PV system performance. Recently, we have proposed and validated through experimental data a 3D model tested as a function of module height, tilt angle, and ground albedo. In this work, through such a model, we studied the role played by the perimeter zones surrounding the PV string, by considering PV strings of 30 or 60 modules. We considered the cases of fixed installation with optimal PV module tilt and of installation with uniaxial horizontal solar tracker. We evaluated the PV energy yield as a function of the size of the perimeter zones for the two cases, i.e., both with and without the solar tracker. In optimal perimeter conditions, we then studied the behavior of bifacial and mono-facial PV strings by varying the geographical location in a large latitude range
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