3,801 research outputs found

    An electric vehicle propulsion system's impact on battery performance: An overview

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    The performance of two types of batteries, lead-acid and nickel-zinc, was measured as a function of the charging and discharging demands anticipated from electric vehicle propulsion systems. The benefits of rapid high current charging were mixed: although it allowed quick charges, the energy efficiency was reduced. For low power (overnight) charging the current wave shapes delivered by the charger to the battery tended to have no effect on the battery cycle life. The use of chopper speed controllers with series traction motors resulted in a significant reduction in the energy available from a battery whenever the motor operates at part load. The demand placed on a battery by an electric vehicle propulsion system containing electrical regenerative braking confirmed significant improvment in short term performance of the battery

    Positively Perplexing E-Books: Digital Natives’ Perceptions of Electronic Information Resources

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    Anecdotal evidence from user surveys and the experiences of information professionals portray a picture that today’s students (i.e., “digital natives”) do not differentiate between the variety of information resources online. The issue of container only becomes problematic to these students when they have to produce a scholarly work and cite their information sources. Then the question becomes, “What is it?” This paper will present preliminary data from a survey of university students on how they recognize and label electronic information resources. The authors will explore such questions as: Do users recognize an e-book as a book? If not, how do they categorize it? Does the amount and placement of labeling from the publisher make a difference in their recognition? Do they differentiate between an academic database and a search engine? Are a newspaper article and a peer-reviewed journal article considered synonymous

    Association of total serum cholesterol with functional outcome following home care rehabilitation in Italian patients with stroke.

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    BACKGROUND: Stroke is a disabling disease. In elderly populations, stroke is the third leading cause of death and the primary cause of reduction in or loss of functional ability and personal autonomy. Possible associations between levels of total serum cholesterol (TC) and both incidence of stroke and functional outcomes after rehabilitation are still under study. OBJECTIVE: To detect positive and negative prognostic factors associated with functional outcomes in first-time stroke patients admitted to an integrated home care rehabilitative program. METHODS: This study enrolled 141 patients with a first-time stroke who were admitted to a home care rehabilitation program. Primary outcome measures were the Barthel activities of daily living (ADL) and mobility indices at the beginning and end of the rehabilitative treatment. The impact of TC and other demographic and clinical variables was analyzed using bivariate and multivariate logistic regression analyses. RESULTS: Age and Short Portable Mental Status Questionnaire (SPMSQ) score were negatively associated with functional outcome. In contrast, elevated TC was positively associated with a better home rehabilitative treatment outcome. Barthel index score at admission was negatively associated with outcomes assessed by the Barthel ADL index and age with outcomes assessed by the Barthel mobility index. In a multivariate logistic regression analysis, SPMSQ score and elevated TC were significantly associated with outcome. Specifically, higher SPMSQ scores were negatively associated with better rehabilitative treatment outcomes, whereas elevated TC was positively associated. CONCLUSIONS: Elevated TC seems to be associated with better functional outcomes in patients with first-time stroke

    Interacting Kasner-type cosmologies

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    It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition of two ideal cosmic fluids, as well as the particular cases of non-interacting and interacting ones, by introducing a phenomenological coupling function q(t)q(t). For two-fluid cosmological scenarios there exist only cosmological scaling solutions, while for three-fluid configurations there exist not only cosmological scaling ones, but also more general solutions. In the case of triply interacting cosmic fluids we can have energy transfer from two fluids to a third one, or energy transfer from one cosmic fluid to the other two. It is shown that by requiring the positivity of energy densities there always is a matter component which violates the dominant energy condition in this kind of anisotropic cosmological scenarios.Comment: Accepted for publication in Astrophysics &Space Science, 8 page

    The current progress of the ALICE Ring Imaging Cherenkov Detector

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    Recently, the last two modules (out of seven) of the ALICE High Momentum Particle Identification detector (HMPID) were assembled and tested. The full detector, after a pre-commissioning phase, has been installed in the experimental area, inside the ALICE solenoid, at the end of September 2006. In this paper we review the status of the ALICE/HMPID project and we present a summary of the series production of the CsI photo-cathodes. We describe the key features of the production procedure which ensures high quality photo-cathodes as well as the results of the quality assessment performed by means of a specially developed 2D scanner system able to produce a detailed map of the CsI photo-current over the entire photo-cathode surface. Finally we present our recent R&D efforts toward the development of a novel generation of imaging Cherenkov detectors with the aim to identify, in heavy ions collisions, hadrons up to 30 GeV/c.Comment: Presented at the Imaging-2006 Conference, Stockholm, Sweden, June 200

    Verso l’ossimoro di una tutela elusiva del diritto all’abitazione? Riflessioni a margine di due pronunce della Corte costituzionale in materia di edilizia residenziale pubblica

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    Il lavoro si propone di approfondire il tema del diritto all’abitazione all’interno dell’attuale contesto economico-istituzionale. In tal senso intende evidenziare il carattere debole ma nello stesso tempo fondamentale di tale diritto nel sistema costituzionale delle tutele sociali, in una prospettiva prima storico-costituzionale, poi legislativa, infine giurisprudenziale. Si vuole, così, proporre un confronto fra questa dimensione costituzionale del diritto all’abitazione e due recenti sentenze della Corte Costituzionale, la n. 38 e la n. 131 del 2016. Dalle pronunce sembra emergere una tutela solo incidentale del diritto: quest’ultimo, nella sopravvenuta condizionalità dello Stato sociale, rischia di non essere più interpretato solamente come debole, ma di essere anche rimesso alla totale discrezionalità del legislatore in base alla disponibilità finanziaria, lasciando aperte delle incognite sulla sua effettiva garanzia

    Accuracy improvement in the TDR-based localization of water leaks

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    A time domain reflectometry (TDR)-based system for the localization of water leaks has been recently developed by the authors. This system, which employs wire-like sensing elements to be installed along the underground pipes, has proven immune to the limitations that affect the traditional, acoustic leak-detection systems. Starting from the positive results obtained thus far, in this work, an improvement of this TDR-based system is proposed. More specifically, the possibility of employing a low-cost, water-absorbing sponge to be placed around the sensing element for enhancing the accuracy in the localization of the leak is addressed. To this purpose, laboratory experiments were carried out mimicking a water leakage condition, and two sensing elements (one embedded in a sponge and one without sponge) were comparatively used to identify the position of the leak through TDR measurements. Results showed that, thanks to the water retention capability of the sponge (which maintains the leaked water more localized), the sensing element embedded in the sponge leads to a higher accuracy in the evaluation of the position of the leak
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