1,721,055 research outputs found
Solarthermische Wasserstofferzeugung: Prozessentwicklung für den Schwefel-Hybrid-Zyklus
No full textZiel der Diplomarbeit ist es, ein optimiertes Prozessschema für den gemischt solar-nuklear betriebenen Schwefel-Hybrid-Prozess zu erarbeiten und eine Beispielanlage dafür auszulegen.
Dabei soll die gezielte Nutzung der Vorteile der jeweiligen Energiequellen einen größeren Gesamtvorteil mit sich bringen. Ein Ranking der möglichen Prozessvarianten und
der Varianten hinsichtlich der Einkopplung von Wärme und Strom wurde anhand eines ausführlichen Kriterienkatalogs im Vorfeld bereits durchgeführt. Es ist vorgesehen, unter
Nutzung der Simulationssoftware Aspen Plus für die aussichtsreichste Variante ein Prozessschema und anschließend ein detailliertes Prozessflussdiagramm zu entwickeln, um alle Massen- und Energieströme innerhalb des Prozesses abzubilden. Die Optimierung des Schemas und des Prozessflussdiagramms wird iterativ erfolgen hinsichtlich Jahreswirkungsgrad, Betriebssicherheit und Praktikabilität. Für einen Modellstandort wird eine hybrid (solarnuklear)
betriebene Anlage auf der Basis des optimierten Flussdiagramms beispielhaft ausgelegt. Die Anlagengröße entspricht gemäß Vereinbarungen mit den Projektpartnern
50 MW bzw. 300 MW thermischer Leistung im Jahresmittel. Die Berechnung der Jahreserträge erlaubt schließlich eine ökonomische Einordnung dieser Technologie und einen
Vergleich mit einer rein solar betriebenen Anlage. Unter Umständen macht dies eine Übertragung von statischen Simulationsmodellen auf dynamische notwendig
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
How to Send a Signal to Fixed Ground Antennas from a Non-Geostationary Satellite
Full text linkThere are orbits which have quasi-stationary periods twice per revolution, as seen from a specific position on
Earth. They could serve as a broadcast alternative for the geostationary orbit and since such orbits are inclined, in
addition they cover the Polar Regions. The conditions for those special cases and the dependency on orbit radius and
inclination are elaborated in this paper. Exemplarily an application for a global information service will be
introduced in combination with the conditions for a repeating ground track using just one single satellite
Parameter Analysis of a Concurrent Engineering Satellite Study
No full textAim of this talk is the analysis of the design parameter space, i.e. the amount of used parameters and their interdependencies observed during the SolmeX Concurrent Engineering (CE) study, a Sun observation satellite mission, which was conducted by the DLR Institute of Space Systems in Bremen. In total a number of 406 parameters have been detected including 9531 interconnections. By the help of the graph theory the structure of those parameters is elaborated counting their vertices and nodes. It builds the basis for the development of a generic design analysis and optimization tool for the CE data model
Feasibility Study Post-ISS Scenario-I - Concurrent Engineering Study Report
Full text linkThe Concurrent Engineering (CE) study Post-ISS Scenario-I took place from 8th to 12th of June 2015 in the Concurrent Engineering Facility (CEF) at the DLR Bremen. The subsystem domains and disciplines were taken by Bigelow Aerospace, Consultants and mainly DLR Bremen staff. The goal of the study has been the investigation of the Base Station concept developed in the frame of the DLR-internal Post-ISS project
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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