928 research outputs found

    A Homogenized Thermal Model For Lithium Ion Batteries

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    In this work homogenization theory is applied to existing thermal models for lithium ion batteries. We study a battery with prismatic cell geometry. The inner region of the battery has a thermal conductivity that is periodic in a local variable. In this work we describe the inner region by a homogenized partial differential equation. The obtained homogenized thermal conductivity tensor is equivalent with the tensor obtained by applying a thermal equivalent-resistance approach. Thermal equivalent-resistance approaches are reported in the literature on thermal modeling of lithium ion batteries. Furthermore, the homogenized thermal conductivity in different directions varies by a factor 10. The outer region of the battery consist of a casing that is wrapped around the inner region. The outer region is described by a nonhomogenized partial differential equation. Both regions is described by the two coupled partial differential equations in dimensionless form. The coupled model is applied to a conventional lithium ion pouch-cell battery with 17.5 Ah capacity. Input data to the model are obtained from experiments. The model is solved in 2 dimensions by means of the finite element method in the FEniCS software. As input parameters, an ambient temperature and an initial condition of 298 (K) are applied. Moreover is the external heat transfer coe cient estimated to be 18 (W/m2 K). Simulations of a 1C discharge from 100 to 10% state of charge is performed. The modeled battery consists in 2 dimensions of a rectangle with long and short sides. It was found that the temperature parallel with the long side varied significant compared with the temperature parallel with the short side. A maximum temperature is achieved in the center of the battery. This occurs at the time just before the battery is at end of discharge. The maximum temperature is 2.4 (K) above the ambient air temperature. A validation of the results are necessary

    Frei geformte Betonbauteile: Finden einer Fertigungsmethode

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    Due to the complexity of the freeform shapes it is often not possible to distinguish any repetitive elements in freeform buildings at all. Most freeform building designs consist of many single or double curved surfaces which require complex shapes for the mould and element edges. Since the costs of the moulds (formwork) for precast concrete make up a significant percentage of the final price per element or per square meter, the feasibility of freeform buildings in precast concrete is still far from optimal. The PhD research carried out at Delft University of Technology, Faculty ofCivil Engineering, aims to improve the applicability of precast concrete through the development of a flexible mould. At the end of the research the design specifications of vital parts of the flexible mould should be described, and supported by theoretical and experimental study as a proof of concept.Structural EngineeringCivil Engineering and Geoscience

    Aktuelle Rechtsprechung des Bundesgerichts im Gesellschaftsrecht – Teil 1

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    Im Beitrag finden Sie eine Zusammenstellung von in der amtlichen Sammlung publizierten und weiteren wichtigen (nicht amtlich publizierten) Entscheiden des Bundesgerichts im Gesellschaftsrecht von Oktober 2016 bis Oktober 2017. Dem Praktiker soll damit eine rasche Übersicht über die Entwicklungen in der bundesgerichtlichen Rechtsprechung gegeben werden. Die Zusammenfassungen der Urteile sind mit Bemerkungen versehen.+ ID der Publikation: unilu_33680 + Sprache: Deutsch + Letzte Aktualisierung: 2018-07-04 16:19:5

    Loyalty and middle class at stake in the General Motors strikes, Flint (Michigan), Summer 1998

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    In June and July 1998, the United Auto Workers Union (UAW) engaged Flint General Motors workers in one of the longest strike to take place lately in United States. Officially, the strike was launched on Health and Safety issues, as globalisation and relocation of the company were non strikeable ones in the bargaining contract. Still, the issue of globalisation and the relationships between the firms and their employees, and the firms and the countries in which they are settled, were clearly at the heart of the conflict. This paper is based on the empirical data we collected in Flint (Michigan) at the beginning of August 1998. It is the result of the individual interviews we conducted with the workers and UAW representatives about their own ideas on the situation. It focuses on what workers think by identifying the words and categories they themselves use to analyse the situation. The paper looks at the national contract signed by GM, Delphi Automotive Systems Corp. and UAW in late September 1999 as an attempt to respond to the real issues addressed by the strikers, that neither GM nor the union could face in 1998 because of juridical reasons ruling negotiations agenda. -- Im Juni / Juli 1998 hat die United Auto Workers Union (UAW) die Mitarbeiter von General Motors in Flint in einen Streik geführt, der zu den längsten Konflikten in der jüngsten amerikanischen Arbeiterbewegung gehört. Gesundheit und Sicherheit am Arbeitsplatz galten als offizieller Streikgrund, da laut gültigem Tarifvertrag gegen Globalisierung und Verlagerung der Produktion in Billiglohnländer nicht gestreikt werden durfte. Dennoch standen Fragen wie Globalisierung, die Beziehungen zwischen den Unternehmen und ihren Arbeitnehmern sowie das Verhältnis zwischen den Unternehmen und den Ländern, in denen sie Produktionsstätten haben, eindeutig im Mittelpunkt des Konflikts. Das Papier basiert auf empirischen Daten, die wir in Flint (Michigan) Anfang August 1998 erhoben haben. Die Daten sind das Ergebnis unserer Einzelgespräche mit streikenden ArbeiterInnen und UAW-VertreterInnen über ihre eigene Analyse der Situation. Der Schwerpunkt des Artikels liegt auf den Aussagen der ArbeiterInnen, das heißt, was sie selber denken, in welche Worte sie ihre Gedanken kleiden und welche Kategorien sie verwenden, mit denen sie die Situation begreifen. Ein Jahr nach diesen langen und schwierigen Konflikten, im September 1999, haben UAW, GM und Delphi einen neuen, nationalweit gültigen Vertrag abgeschlossen. In dieser Studie wird er als ein Versuch betrachtet, eine Antwort auf die realen Streitfragen und Probleme des Sommers 1998 zu finden, die die Tarifparteien zu dem damaligen Zeitpunkt aus vertraglichen und juristischen Gründen nicht bewältigen konnten.

    Facing femininities : women in the National Portrait Gallery, 1856-1899.

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DXN029234 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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