8,938 research outputs found

    Wheelchair Tire Change

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    This project consists of a rear wheel wheelchair lift to be designed and created by a Cal Poly senior project team. This project was created for injured veteran Ms. Landeen who has the trouble of tracking mud into her house because of dirty wheelchair tires. The project was presented by the non-profit organization The Quality of Life Plus (QL+) Program. Much like when you remove your shoes coming into your home, Ms. Landeen needs a way to exchange her outdoor wheels for her clean indoor wheels. The expected outcome of this project is a fully functioning device that will safely and effectively allow Ms. Landeen to independently change her tires. The following report details the problem given, background research on current products, initial analysis to define the problem, the ideation process performed by the team, concept and prototype designs, design iteration, manufacturing, design verification, and testing of the final design prototype

    γ\gamma - Z interferometry at a Φ\Phi-factory

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    We analyze the possibilities that the proposed Φ\Phi-factories offer to measure γZ\gamma-Z interference. In the unpolarized beam case, we study different signatures in the ρπ\rho \pi channel, taking advantage of the presence of the near-by a1a_1 resonance. We build a C-odd forward-backward asymmetry, estimated to be around 10510^{-5}, and (P-even, T-even) and (P-odd, T-odd) alignments of the ρ\rho, to be seen from the angular distribution of its ππ\pi \pi decay products. With polarized electrons a left-right asymmetry around 2×1042\times 10^{-4} is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the Z0ssˉZ^0-s\bar{s} vector coupling. In the ρπ\rho \pi channel, a combined left-right forward-backward asymmetry is considered.Comment: 29 pages + 6 figures. Some changes concerning a1a_1 observables, especially related with possible 2 γ\gamma contribution

    Gait switches in deep-diving beaked whales : biomechanical strategies for long-duration dives

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    Work in the Canary Islands was funded by the Office of Naval Research and the National Oceanographic Partnership Program (NOPP), by a consortium consisting of the Canary Islands Government, the Spanish Ministry of Environment and the Spanish Ministry of Defense and by the European environmental funding LIFE-INDEMARES program for the inventory and designation of the Natura 2000 network in marine areas of the Spanish territory, headed by Fundacion Biodiversidad, with additional support from the Cabildo Insular of El Hierro. Fieldwork in the Ligurian Sea was funded by NOPP. Research in the Gully was funded by the Strategic Environmental Research and Development Program (SERDP) programs RC-2113 and RC-2337. L.M.M.L. was funded by a ‘la Caixa’ Fellowship within the 2010 UK Framework Programme. N.A.d.S. was funded for this study by ONR and by the EU FP7 Marie Curie project SOUNDMAR. M.J. was funded by a Marie Curie Career Integration Grant, and from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N = 10; Ziphius cavirostris, N = 9; and Hyperoodon ampullatus, N = 2) to characterize their swimming gaits. In addition to continuous stroking and stroke and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorsoventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise similar to 80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth.PostprintPeer reviewe

    Top pair Asymmetries at Hadron colliders with general ZZ' couplings

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    Recently it has been shown that measurement of charge asymmetry of top pair production at LHC excludes any flavor violating ZZ' vector gauge boson that could explain Tevatron forward-backward asymmetry (FBA). We consider the general form of a ZZ' gauge boson including left-handed, right-handed vector and tensor couplings to examine FBA and charge asymmetry. To evaluate top pair asymmetries at Tevatron and LHC, we consider Bq0B^0_q mixing constraints on flavor changing ZZ' couplings and show that this model still explain forward-backward asymmetry at Tevatron and charge asymmetry can not exclude it in part of parameters space.Comment: 18 pages, 7 figure

    Two-loop SUSY QCD corrections to the chargino masses in the MSSM

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    We have calculated the two-loop strong interaction corrections to the chargino pole masses in the DRbar'-scheme in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters. We have performed a detailed numerical analysis for a particular point in the parameter space and found corrections of a few tenths of a percent. We provide a computer program which calculates chargino and neutralino masses with complex parameters including the one-loop corrections and all two-loop SQCD effects.Comment: 12 pages, 11 figures, references modified, clarifications adde

    Empirical analysis of daily cash flow time series and its implications for forecasting

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    Usual assumptions on the statistical properties of daily net cash flows include normality,absence of correlation and stationarity. We provide a comprehensive study based on a real-world cash flow data set showing that: (i) the usual assumption of normality, absence of correlation and stationarity hardly appear; (ii) non-linearity is often relevant for forecasting; and (iii) typical data transformations have little impact on linearity and normality. This evidence may lead to consider a more data-driven approach such as time-series forecasting in an attempt to provide cash managers with expert systems in cash management

    Mechanical loading stimulates hypertrophy in tissue-engineered skeletal muscle: Molecular and phenotypic responses

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    Mechanical loading of skeletal muscle results in molecular and phenotypic adaptations typified by enhanced muscle size. Studies on humans are limited by the need for repeated sampling, and studies on animals have methodological and ethical limitations. In this investigation, three-dimensional skeletal muscle was tissue-engineered utilizing the murine cell line C2C12, which bears resemblance to native tissue and benefits from the advantages of conventional in vitro experiments. The work aimed to determine if mechanical loading induced an anabolic hypertrophic response, akin to that described in vivo after mechanical loading in the form of resistance exercise. Specifically, we temporally investigated candidate gene expression and Akt-mechanistic target of rapamycin 1 signalling along with myotube growth and tissue function. Mechanical loading (construct length increase of 15%) significantly increased insulin-like growth factor-1 and MMP-2 messenger RNA expression 21 hr after overload, and the levels of the atrophic gene MAFbx were significantly downregulated 45 hr after mechanical overload. In addition, p70S6 kinase and 4EBP-1 phosphorylation were upregulated immediately after mechanical overload. Maximal contractile force was augmented 45 hr after load with a 265% increase in force, alongside significant hypertrophy of the myotubes within the engineered muscle. Overall, mechanical loading of tissue-engineered skeletal muscle induced hypertrophy and improved force production

    The A Dependence of Open Charm and Bottom Production

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    We study inclusive heavy quark and exclusive heavy quark pair production in pp, pA and AA interactions. Intrinsic transverse momentum is introduced in pp interactions. Nuclear effects, limited to kTk_T broadening and nuclear shadowing, are introduced in pA and AA interactions. The nuclear dependence is studied over a range of energies, both in fixed target and collider setups.Comment: 69 pages, 42 .eps figures, to appear in the Proceedings of the Hard Probe Collaboratio

    Decontamination of Diesel particles from air by using the Counterfog (R) system

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    The existence of particles with diameter under 10m in air is strongly correlated with respiratory diseases. These particles are profusely produced by heating systems, traffic, and Diesel engines creating a serious problem to modern cities. Natural mechanisms removing particles from the atmosphere are too slow to deal with the huge amount of particles daily released by human activity. The objective of this work is to measure the effectiveness of a new technology called Counterfog (R) to eliminate airborne particles. The results show that Counterfog (R) is able to wash out PM10, PM5, and PM2.5 Diesel-generated airborne particles quite efficiently.This work has been funded by the FP7-SEC-2012-1 program of the EU Commission under grant number 312804

    On high-speed turning of a third-generation gamma titanium aluminide

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    Gamma titanium aluminides are heat-resistant intermetallic alloys predestined to be employed in components suffering from high mechanical stresses and thermal loads. These materials are regarded as difficult to cut, so this makes process adaptation essential in order to obtain high-quality and defect-free surfaces suitable for aerospace and automotive parts. In this paper, an innovative approach for longitudinal external high-speed turning of a third-generation Ti-45Al-8Nb- 0.2C-0.2B gamma titanium aluminide is presented. The experimental campaign has been executed with different process parameters, tool geometries and lubrication conditions. The results are discussed in terms of surface roughness/integrity, chip morphology, cutting forces and tool wear. Experimental evidence showed that, due to the high cutting speed, the high temperatures reached in the shear zone improve chip formation, so a crack-free surface can be obtained. Furthermore, the use of a cryogenic lubrication system has been identified in order to reduce the huge tool wear, which represents the main drawback when machining gamma titanium aluminides under the chosen process condition
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