465 research outputs found

    Influences of drive torque distribution on road vehicle handling and efficiency

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    With recent developments in active vehicle drivelines and the trend towards the use of electric propulsion in road vehicles, the optimal way to distribute power in a vehicle has become an interesting area of research. Automobiles with Active Torque Distribution (ATD) capabilities demonstrate improved handling and stability, and there is the possibility that energy consumption could be reduced through better distribution of power. Motorcycles that can apply some of the drive torque at the front wheel exist, with the aim of increasing tractive force on low-friction surfaces. Research is required to investigate the effects of torque distribution on the handling and efficiency of motorcycles and automobiles. In this work, multibody models of both motorcycles and automobiles are created, and are verified with existing mathematical models. The vehicle models include the influences of suspension, aerodynamics and gyroscopic effects, and complex tyre models are used that account for combined lateral and longitudinal slip and the vertical loading situation. Simple driver models are used to control the speed and yaw rate of the vehicles while they undertake a series of on-road manoeuvres. Left–right torque vectoring is shown to be effective in the alteration of the steady-state handling characteristics of the automobile, and front–rear torque vectoring has a small effect at high speeds. A slight increase is possible in transient responsiveness at moderate speeds, but instabilities can be exacerbated at high speeds. In motorcycles, the torque distribution has only a small effect on handling in steady-state situations. During straight-running, the optimum efficiency of the both vehicles is shown to occur when the torque is distributed in proportion with the vertical load at the tyres. During cornering, a slight additional bias towards the front wheel(s) is beneficial. Despite the alteration in handling characteristics made available through ATD, the effects of weight distribution and tyre characteristics still dominate. At normal speeds, almost the same effect on automobile handling can be achieved through left–right torque vectoring in a front- or rear-wheel-drive vehicle, as in a four-wheel-drive vehicle. In these steady-state situations, the energy efficiency of the vehicles varies only by small amounts, with aerodynamic and lateral slip dissipations dominating. The models presented in this thesis, and the results and conclusions obtained from them, offer the designers of future vehicles useful information for the improvement of vehicle handling, efficiency and quality

    Influences of drive torque distribution on road vehicle handling and efficiency

    Get PDF
    With recent developments in active vehicle drivelines and the trend towards the use of electric propulsion in road vehicles, the optimal way to distribute power in a vehicle has become an interesting area of research. Automobiles with Active Torque Distribution (ATD) capabilities demonstrate improved handling and stability, and there is the possibility that energy consumption could be reduced through better distribution of power. Motorcycles that can apply some of the drive torque at the front wheel exist, with the aim of increasing tractive force on low-friction surfaces. Research is required to investigate the effects of torque distribution on the handling and efficiency of motorcycles and automobiles. In this work, multibody models of both motorcycles and automobiles are created, and are verified with existing mathematical models. The vehicle models include the influences of suspension, aerodynamics and gyroscopic effects, and complex tyre models are used that account for combined lateral and longitudinal slip and the vertical loading situation. Simple driver models are used to control the speed and yaw rate of the vehicles while they undertake a series of on-road manoeuvres. Left–right torque vectoring is shown to be effective in the alteration of the steady-state handling characteristics of the automobile, and front–rear torque vectoring has a small effect at high speeds. A slight increase is possible in transient responsiveness at moderate speeds, but instabilities can be exacerbated at high speeds. In motorcycles, the torque distribution has only a small effect on handling in steady-state situations. During straight-running, the optimum efficiency of the both vehicles is shown to occur when the torque is distributed in proportion with the vertical load at the tyres. During cornering, a slight additional bias towards the front wheel(s) is beneficial. Despite the alteration in handling characteristics made available through ATD, the effects of weight distribution and tyre characteristics still dominate. At normal speeds, almost the same effect on automobile handling can be achieved through left–right torque vectoring in a front- or rear-wheel-drive vehicle, as in a four-wheel-drive vehicle. In these steady-state situations, the energy efficiency of the vehicles varies only by small amounts, with aerodynamic and lateral slip dissipations dominating. The models presented in this thesis, and the results and conclusions obtained from them, offer the designers of future vehicles useful information for the improvement of vehicle handling, efficiency and quality

    Panel Discussion: Foreign Governmental Control of Multinational Corporations Marketing in the United States

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    This panel discussion focuses on debating the regulation of companies operating in more than one country. The primary emphasis is placed on oil companies

    Computational fluid dynamics analysis in support of the simplex turbopump design

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    Simplex is a turbopump that is being developed at NASA/Marshall Space Flight Center (MSFC) by an in-house team. The turbopump consists of a single-stage centrifugal impeller, vaned-diffuser pump powered by a single-stage, axial, supersonic, partial admission turbine. The turbine is driven by warm gaseous oxygen tapped off of the hybrid motor to which it will be coupled. Rolling element bearings are cooled by the pumping fluid. Details of the configuration and operating conditions are given by Marsh. CFD has been used extensively to verify one-dimensional (1D) predictions, assess aerodynamic and hydrodynamic designs, and to provide flow environments. The complete primary flow path of the pump-end and the hot gas path of the turbine, excluding the inlet torus, have been analyzed. All CFD analyses conducted for the Simplex turbopump employed the pressure based Finite Difference Navier-Stokes (FDNS) code using a standard kappa-epsilon turbulence model with wall functions. More detailed results are presented by Garcia et. al. To support the team, loading and temperature results for the turbine rotor were provided as inputs to structural and thermal analyses, and blade loadings from the inducer were provided for structural analyses

    Digital Signal Processing

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    Contains an introduction and reports on fifteen research projects.National Science Foundation FellowshipU.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation (Grant ECS 84-07285)Sanders Associates, Inc.U.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028)AT&T Bell Laboratories Doctoral Support ProgramCanada, Bell Northern Research ScholarshipCanada, Fonds pour la Formation de Chercheurs et /'Aide a la Recherche Postgraduate FellowshipCanada, Natural Science and Engineering Research Council Postgraduate FellowshipAmoco Foundation FellowshipFannie and John Hertz Foundation Fellowshi

    Deploying the NASA Valkyrie Humanoid for IED Response: An Initial Approach and Evaluation Summary

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    As part of a feasibility study, this paper shows the NASA Valkyrie humanoid robot performing an end-to-end improvised explosive device (IED) response task. To demonstrate and evaluate robot capabilities, sub-tasks highlight different locomotion, manipulation, and perception requirements: traversing uneven terrain, passing through a narrow passageway, opening a car door, retrieving a suspected IED, and securing the IED in a total containment vessel (TCV). For each sub-task, a description of the technical approach and the hidden challenges that were overcome during development are presented. The discussion of results, which explicitly includes existing limitations, is aimed at motivating continued research and development to enable practical deployment of humanoid robots for IED response. For instance, the data shows that operator pauses contribute to 50\% of the total completion time, which implies that further work is needed on user interfaces for increasing task completion efficiency.Comment: 2019 IEEE-RAS International Conference on Humanoid Robot

    SN 2022jox: An extraordinarily ordinary Type II SN with Flash Spectroscopy

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    We present high cadence optical and ultraviolet observations of the Type II supernova (SN), SN 2022jox which exhibits early spectroscopic high ionization flash features of \ion{H}{1}, \ion{He}{2}, \ion{C}{4}, and \ion{N}{4} that disappear within the first few days after explosion. SN 2022jox was discovered by the Distance Less than 40 Mpc (DLT40) survey \sim0.75 days after explosion with followup spectra and UV photometry obtained within minutes of discovery. The SN reached a peak brightness of MV_V \sim -17.3 mag, and has an estimated 56^{56}Ni mass of 0.04 M_{\odot}, typical values for normal Type II SNe. The modeling of the early lightcurve and the strong flash signatures present in the optical spectra indicate interaction with circumstellar material (CSM) created from a progenitor with a mass loss rate of M˙103102 M yr1\dot{M} \sim 10^{-3}-10^{-2}\ M_\odot\ \mathrm{yr}^{-1}. There may also be some indication of late-time CSM interaction in the form of an emission line blueward of Hα\alpha seen in spectra around 200 days. The mass-loss rate is much higher than the values typically associated with quiescent mass loss from red supergiants, the known progenitors of Type II SNe, but is comparable to inferred values from similar core collapse SNe with flash features, suggesting an eruptive event or a superwind in the progenitor in the months or years before explosion.Comment: Submitted to Ap

    Political masculinities, crisis tendencies, and social transition: Toward an understanding of change

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    This introduction to the special issue on “Political Masculinities and Social Transition” rethinks the notion of “crisis in masculinity” and points to its weaknesses, such as cyclical patterns and chronicity. Rather than viewing key moments in history as points of rupture, we understand social change as encompassing ongoing transitions marked by a “fluid nature” (Montecinos 2017, 2). In line with this, the contributions examine how political masculinities are implicated within a wide range of social transitions, such as nation building after war, the founding of a new political party in response to an economic crisis, an “authoritarian relapse” of a democracy, attempts at changing society through terrorism, rapid industrialization as well as peace building in conflict areas. Building on Starck and Sauer’s definition of “political masculinities” we suggest applying the concept to instances in which power is explicitly either being (re)produced or challenged. We distinguish between political masculinities that are more readily identified as such (e.g., professional politicians) and less readily identified political masculinities (e.g., citizens), emphasizing how these interact with each other. We ask whether there is a discernible trajectory in the characteristics of political masculinities brought about by social transition that can be confirmed across cultures. The contributors’ findings indicate that these political masculinities can contribute to different kinds of change that either maintain the status quo, are progressive, retrogressive, or a mixture of these. Revolutionary transitions, it seems, often promote the adherence to traditional forms of political masculinity, whereas more reformatory transition leaves discursive spaces for argument

    Digital Signal Processing

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    Contains an introduction and reports on twenty research projects.National Science Foundation (Grant ECS 84-07285)U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation FellowshipSanders Associates, Inc.U.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028)Canada, Bell Northern Research ScholarshipCanada, Fonds pour la Formation de Chercheurs et l'Aide a la Recherche Postgraduate FellowshipCanada, Natural Science and Engineering Research Council Postgraduate FellowshipU.S. Navy - Office of Naval Research (Contract N00014-81-K-0472)Fanny and John Hertz Foundation FellowshipCenter for Advanced Television StudiesAmoco Foundation FellowshipU.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028
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