550 research outputs found

    Development of Surrogate Hand for Impact Tests

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    Despite continuous advancements in technology and safety procedures, hand injuries are still a significant problem in many industries. Metacarpal gloves are often used by workers to protect their hands against impacts, cuts, and other hazards. Importantly, testing the level of impact protection offered by different designs of metacarpal gloves cannot be done with living subjects. This limitation requires the use of a surrogate hand which can be used consistently and systematically in controlled impact tests. This work focuses on the development of a surrogate hand which can be manufactured and used for this purpose. The surrogate hand developed in this work is comprised of a bone structure and a flexible synthetic gel material, and the hand design is based on digital models obtained through laser scanning of bone and hand shapes. These digital models were scaled and assembled using a mesh editing software to generate a representative hand with the required size and posture. The resulting hand model was materialized with a 3D-printed bone structure surrounded by synthetic gel with shape, proportions, and flexibility resembling that of an actual hand

    Evolution of crystalline electric field effects, superconductivity, and heavy fermion behavior in the specific heat of Pr(Os1x_{1-x}Rux_x)4_4Sb12_{12}

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    Specific heat C(T)C(T) measurements were made on single crystals of the superconducting filled skutterudite series Pr(Os1x_{1-x}Rux_x)4_4Sb12_{12} down to 0.6 K. Crystalline electric field fits in the normal state produced parameters which were in agreement with previous measurements. Bulk superconductivity was observed for all values of the Ru concentration xx with transition temperatures consistent with previous experiments, confirming a minimum in TcT_{c} at x=0.6x=0.6. The C(T)C(T) data below TcT_{c} appear to be more consistent with power law behavior for x=0x=0 (PrOs4_4Sb12_{12}), and with exponential behavior for 0.05x0.20.05 \leq x \leq 0.2. An enhanced electronic specific heat coefficient γ\gamma was observed for x0.4x \leq 0.4, further supporting x0.6x \simeq 0.6 as a critical concentration where the physical properties abruptly change. Significant enhancement of ΔC/Tc\Delta C/T_{c} above the weak coupling value was only observed for x=0x=0 and x=0.05x=0.05.Comment: 16 pages, 5 figures, submitted to Physical Review B. v2: text added and figures modifie

    Assessment of the U and Co magnetic moments in UCoGe by X-ray magnetic circular dichroism

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    The ferromagnetic superconductor UCoGe has been investigated by high field X-ray magnetic circular dichroism (XMCD) at the U-M4,5_{4,5} and Co/Ge-K edges. The analysis of the branching ratio and XMCD at the U-M4,5_{4,5} edges reveals that the U-5ff electrons count is close to 3. The orbital (0.70μB\sim0.70\,\mu_B) and spin (0.30μB\sim-0.30\,\mu_B) moments of U at 2.1K and 17T (H//c) have been determined. Their ratio (2.3\sim-2.3) suggests a significant delocalization of the 5ff electron states. The similar field dependences of the local U/Co and the macroscopic magnetization indicate that the Co moment is induced by the U moment. The XMCD at the Co/Ge-K edges reveal the presence of small Co-4pp and Ge-4pp orbital moments parallel to the macroscopic magnetization. In addition, the Co-3dd moment is estimated to be at most of the order of 0.1μB\mu_B at 17T. Our results rule out the possibility of an unusual polarisability of the U and Co moments as well as their antiparallel coupling. We conclude that the magnetism which mediates the superconductivity in UCoGe is driven by U.Comment: 4 figures + supplementary materia

    Hidden Consequences: Examining the Impact of NIL on Athlete Well-Being

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    With the NCAA\u27s NIL policy changes, many athletes will likely need to solve the issue of brand management, with many of them assuming the role themselves. Taking on this role will likely lead to even more investment in their athlete identity (i.e., role engulfment), which has negative consequences for the athlete (Hatteberg, 2020). Guided by the literature on role engulfment, this article investigates the hidden effects NIL may have on collegiate athletes and their well-being, along with various branding and legal implications

    Pressure induced effects on the Fermi surface of superconducting 2H-NbSe2_2

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    The pressure dependence of the critical temperature TcT_c and upper critical field Hc2(T)H_{c2}(T) has been measured up to 19 GPa in the layered superconducting material 2H-NbSe2_2. Relating the behavior of Hc2(T)H_{c2}(T) to Fermi surface parameters, we find that the electron phonon coupling of the 2D Nb 4d derived bands shows a peak at 5 GPa when the charge density wave (CDW) order is suppressed. On the other hand, Tc(P)T_c(P) shows a bell shaped curve with a maximum at 10.5 GPa, well above the pressure for the suppression of the CDW order. Changes in the band structure produce this shift in the maximum of Tc(P)T_c(P), demonstrating that 2H-NbSe2_2 shows important differences with respect to other compounds where TcT_c has a maximum in the temperature-density phase diagram shaped by the suppression of another, non-superconducting, ground state.Comment: 5 pages, 4 figures. Small changes in discussion. Typos correcte

    Magnetic field dependence of the density of states in the multiband superconductor β\beta-Bi2_2Pd

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    We present very low temperature scanning tunneling microscopy (STM) experiments on single crystalline samples of the superconductor β\beta-Bi2_2Pd. We find a single fully isotropic superconducting gap. However, the magnetic field dependence of the intervortex density of states is higher than the one expected in a single gap superconductor, and the hexagonal vortex lattice is locked to the square atomic lattice. Such increase in the intervortex density of states and vortex lattice locking have been found in superconductors with multiple superconducting gaps and anisotropic Fermi surfaces. We compare the upper critical field Hc2(T)H_{c2}(T) obtained in our sample with previous measurements and explain available data within multiband supercondutivity. We propose that β\beta-Bi2_2Pd is a single gap multiband superconductor. We anticipate that single gap multiband superconductivity can occur in other compounds with complex Fermi surfaces.Comment: 8 pages, 7 figure
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