• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 137
  • 2
  • 2
  • Tagged with
  • 141
  • 128
  • 125
  • 32
  • 28
  • 24
  • 14
  • 14
  • 14
  • 14
  • 14
  • 8
  • 8
  • 8
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Das Dilemma der deutschen Schulgrammatik - The Dilemma of Teaching German Grammar in School

Nilsson, Torsten Per 04 July 2003 (has links)
Throughout nineteen chapters the problems of teaching grammar are discussed. Only recently the argument whether grammar is useful or not has been newly engaged. Just like an encyclopaedia the major factors in this argument are presented here. This Work includes an extensive collection of source material and bibliographic notes. The different position of the discussion are critically analysed and the demands and requirements for teaching grammar are clearified.
122

Entwicklung eines portablen PEM-Brennstoffzellensystems mit Bipolarplatten aus einem elektronisch leitfaehigen thermoplastischen Compound-Material / Development of a portable PEM-Fuel Cell System containing electric conductive thermoplastic Compound Bipolar Plates

Niemzig, Oliver 04 July 2006 (has links)
In order to meet the cost targets of PEM fuel cells for commercialization significant cost reductions of cell stack components like membrane/electrode assemblies and bipolar plates have become key aspects of research and development. Central topics of his work are the bipolar plates and humidification for portable applications. Best results concerning conductivity of an extensive screening of a variety of carbon polymer compounds with polypropylene as matrix could be achieved with the carbon black/graphite/polypropylene-base system. Successful tests of this material in a fuel cell stack could be performed as well as the proof of suitability concerning material- and manufacturing costs. Dependent on application a decrease of material cost to 2 ¤/kg to 1,8 ¤/kW seems to be possible. Finally bipolar plates consisting of a selected carbon polymer compound were successfully integrated and tested in a 20-cell stack which was implemented in a portable PEFC-demonstrator unit with a power output between 50 and 150 W.
123

Reisemotive, Reiseverhalten und Wahrnehmungen deutscher Touristen in Norwegen als Grundlage der Entwicklung neuer Konzepte für die norwegische Tourismuswirtschaft - Motives, behaviour and perception of German tourists in Norway as a basis for new Norwegian tourism concepts

Kliem, Thomas 30 June 2003 (has links)
This dissertation is a result of researches between 1996-2002. 1.351 Germans were interviewed in Germany and Norway. The researches focused on the motives of German tourists, their behaviour and perception. Very important is also the description of the Norwegian image. The image is old-fashioned and shows a country as it existed in den 1950s. The dissertation gives a survey about the history of tourism in Norway, reflects facts of the current tourism (number of visitors, accommodation,) and gives information about the different attractions. Since 1994 the number of German tourists is decreasing, which are the largest tourist group in Norway. Especially a huge number of camping tourists do not visit this Scandinavian country anymore and a large number of German camping tourists with recreational vehicles stay apart the campgrounds (wild camping). This type of traveller ('autarktyp') were detailed interviewed concerning his behaviour and his perception. The analysed problems are wild camping, less recreation, consumption, long routes, tourism along main routes and locally high density of tourism. Finally the dissertation offers Solutions to solve these problems for example new forms of travelling, new types of camping sites and demands authors of travel guides to use their influence.
124

Vergleich deutscher und französischer Anzeigenwerbung: Standardisierung versus kulturbedingte Differenzierung verbalen und non-verbalen Inhalts - Comparing French and German advertisings: standardization vs. adaptation of verbal and non-verbal content

Hols, Simone 18 July 2003 (has links)
Will German car advertisings be successful in a French environment if translated literally and vice versa? This study elaborates an analysis methodology for print advertising that results from a broad overlook over related issues. Advertising is seen as a mirror of society that reflects its specific culture. As such, significant data about the German and the French culture can be extracted from advertisings by analyzing the verbal and non-verbal content. This study relates research in semiology, text gendres, verbal and non-verbal communication, and content analysis. The extracted information is useful in synthesizing qualitative and quantitative aspects of current research in the domain of advertisings. The results indicate that nowadays advertisings show important differences in the appeal as well as in the stylistic design/execution in form of written texts and images. The conclusion of this research is antagonistic to the influencial thesis of the world as one global market (Levitt, 1983).
125

Zusammenhang zwischen Oberflächenenergie und Adhäsionsvermögen von Polymerwerkstoffen am Beispiel von PP und PBT und deren Beeinflussung durch die Niederdruck-Plasmatechnologie

Gleich, Henning 15 July 2004 (has links)
Im Mittelpunkt der Dissertation steht der Zusammenhang zwischen Oberflächenenergie und Adhäsionsvermögen von Polymerwerkstoffen. Die Untersuchung der erreichbaren KLebfestigkeit erfolgt am Beispiel von PP und PBT. Zur reproduzierbaren Modifikation der Fügeteiloberflächen wird systematisch die Niederdruck-Plasmatechnologie eingesetzt und eine neue Optimierungsstrategie zur schnellen Findung erfolgreicher Prozessparameter entwickelt und beschrieben. Für die untersuchten Klestoff-/Substrat-Systeme wird eine Korrelation zwischen Oberflächenenergie - insbesondere der Polarität - und der Verbundfestigkeit nachgewiesen. Diese Korrelation erlaubt ein Scale up der im Labormassstab erreichten Ergebnisse in Produktionsprozesse.
126

Experimentelle Untersuchung und Modellierung der Löslichkeit von Kalkstein und Gips in wässerigen Systemen bei höheren Ionenstärken - Experimental investigation und modelling of solubility of limestone and gypsum in water systems at higher ionic strengths

Loos, Dieter 27 August 2003 (has links)
The detailed investigations of solubility of limestone und gypsum are essential for optimization of process conditions and operating material consumption in the flue gas scrubbers. This study compares thermodynamic predictions based on the Pitzer model for electrolyte activities with experimental data obtained from salt (gypsum, limestone, calcium adipat) solubility tests in aqueous model systems at high ionic strengths under different partial pressures of carbon dioxide. The high ionic strengths in these aqueous suspensions were achieved by addition of calcium chloride, calcium formate und calcium acetate. By means of measured data the Pitzer interaction parameters for ionic pairs Ca2+/HCO3-, Ca2+/SO42-, Ca2+/HCOO-, Ca2+/CH3COO- and Ca2+/(CH4)2(COO)22- at ionic strength up to 8 mol∙kg-1 were fitted and verified. The Pitzer parameters for interaction between calcium ions and carboxylic acid ions were published in this work for the first time. Also for the first time, the values of standard free energies of formation of calcium formate, calcium acetate and calcium adipate are published. The new model parameters allow a better calculation of thermodynamic equilibriums at industrial processes of flue gas cleaning.
127

Mensch - Maschine - Interface : Studien zu einer Theorie der Mensch-Computer-Interaktion / Men - Machine - Interface : Studies towards a theory of human-computer-interaction

Hohmann, Sandra 11 September 2003 (has links)
The thesis at hand shall be a contribution to describe the Interaction between men and computer adequately and moreover to take into consideration empirical tests. In a first step, relevant theoretical linguistic approaches will be introduced. In this context, the class of speech-acts which are called 'computives' and have been developed by Schmitz, will decisively be enhanced by semiotical aspects. In a next step, the usefulness of empirical tests and the relevance of physiological data will be pointed out to reveal the stressors and to avoid them in future. Finally, possible research projects for the future according to the new theory of man-computer-interaction are described.
128

Berufliche Weiterbildung und Kompetenzentwicklung zur Bewältigung diskontinuierlicher Erwerbsverläufe - The role of occupational further training and development of competencies in coping with discontinuous life-courses

Naevecke, Stefan 04 September 2003 (has links)
The thesis in hand analyses and discusses the predominance of economic utilization and of the socio-political and labour market principals of subsidy in the policy and practice of further education and training in a manner critical of corresponding ideologies and concepts. This provides a basis for the development of practice of further education that takes into account systematically the subjective perspective on interests in vocational competence development and that is compatible to the utilization interests of companies and the labour market as well. The reference to the subjective perspective of interest means in distance to socio-economical and political-normative positions such conditions on the supply side of further education and training that put the employees in a position to synthesise their interest in maintaining vocational competence and employability on the labour market with their aspirations in occupational and private life-course.
129

Verkörperte Zeiträume : eine Auseinandersetzung mit der Land Art in den Werken von Andy Goldsworthy, Richard Long und Walter De Maria / Building time : a view on the Land Art of Andy Goldsworthy, Richard Long and Walter De Maria

Ilschner, Frank 08 October 2004 (has links)
An analytical comparing study of Land Art and its national and international aspects, dealing with Andy Goldsworthy in the first place. Material and Form are not the main subject of the discussion but the language in which the artists show their views on nature. The paper gives a translation of the artists' language and makes it readable. Connections are made between several cultural and social aspects such as religion, spirituality, Zeitgeist, science, art, music, theatre, literature, mass media, sport and nature. Description leads to an analysis of the metaphysical level of Land Art.
130

Einfluss von Schwefelverbindungen in flüssigen Kohlenwasserstoffen auf ein Brennstoffzellen-Gesamtsystem am Beispiel eines Katalytischen Crackers mit nachgeschalteter PEMFC / The Influence of Sulfur Compounds in Liquid Hydrocarbons on a Fuel Cell System, like Catalytic Cracker and Connected PEMFC

Benz, Wolfgang 19 September 2005 (has links)
Arising from the discussion about a sustainable development of the energy sector, more and more interest of different industrial branches (e.g. in the automotive field or by the energy supply companies) is actually directed to the use of fuel cells. They show high degrees of ef-ficiency, little pollution and the ability of combined heat and power generation, and moreover they are modularly built. As a fuel they need hydrogen, but the infrastructure of its supply is much worse than necessary. So, at least for a time of transition, hydrogen must be produced from hydrocarbon fuels. A new idea is the hydrogen production from liquid higher hydrocar-bon compositions, as diesel fuel, in a catalytic cracker. This diesel processor is based on a technology developed by the University of Essen-Duisburg at Duisburg. Liquid higher hydrocarbons, as diesel, also contain different sulfur compounds. The aim of this work was to gain knowledge about the influence of sulfur to a complete catalytic cracker system. The study consists of two parts, the first dealing with the influence of sulfur com-pounds to the catalytic cracker itself, and the second with the influence of the products of the reaction of sulfur compounds flowing with the resultant gas into the low-temperature Polymer Electrolyte Membrane Fuel Cell, PEMFC. In the catalytic cracker the influence of sulfur on the activity and the hydrogen selectivity of catalysts of two different precious metals used separately as well as in mixture is investi-gated. Furthermore, the catalysts stability under the cracking temperature of nearly 1,200 K is tested. As an example, the effect of sulfur-containing fuel to a PEMFC is shown and analysed. Moreover, a mathematical-physical model is developed, describing the effects of the degra-dation of a PEMFC by sulfur contamination. Finally, the efficiency of a desulfurizing unit, pre-connected to the fuel cell to extend its lifetime, is investigated.

Page generated in 0.0246 seconds