1,720,966 research outputs found
Thermo-Hydraulic Simulations of cases tested on District Heating Test facility "District LAB"
No full textEntwicklung eines Konzepts zur Software-Hardware-Kommunikation und Regelung der Versuchseinrichtung "District LAB"
No full textZiel dieser Masterarbeit ist es zu beantworten, welche Regelung für die HIL-Einheiten des geplanten ""District LABs"" geeignet sind und welche Regelparameter eingestellt werden müssen, um die geplanten Szenarien mit möglichst geringer Abweichung zu gegebenen Lastprofilen effizient umzusetzen. Hierfür werden zunächst die hydraulischen Komponenten gemäß den vorhandenen Unterlagen in MATLAB/Simulink mit Hilfe der Carnot-Toolbox modelliert. Anschließend wird das Übertragungsverhalten von den Wärmeübertragern aufgenommen und ausgewertet. Danach werden die Kennlinien von den Drosseln und Wärmepumpen analysiert. In Kombination mit den technischen Anforderungen werden passende Regelstrukturen für die einzelnen Komponenten entwickelt. Für den Wärmeübertrager zwischen HIL-Einheit und DHC wird eine Vorsteuerung zur Regelung der Leistung und zum Entkoppeln von Leistungsregelung und Temperaturregelung entwickelt. Die Temperaturregelung wird durch einen PI-Regler realisiert. Diese Regelstruktur wird auf den WÜ von HC und CC übertragen. Zum Einbinden der vorgeschalteten Drosseln müssen die P und I Werte angepasst werden. Zur Regelung der Wärmepumpe wird ein virtueller Speicher implementiert, Da die Wärmepumpen nur bei bestimmten Leistungsstufen arbeiten können. Die variable Leistungsabnahmewird damit einhergehend in einer virtuellen HIL-Einheit realisiert. Für die Wärmepumpe selbst wird ein Zweipunktregler kombiniert mit einer vorgesteuerten Volumenstromregelung implementiert. Diese wird durch einen Integrator korrigiert, um Abweichungen zwischen Datenblatt und realen Komponenten auszugleichen. Die einzelnen Komponenten werden zu Gesamtmodellen der HIL-Einheiten zusammengesetzt und um eine Steuerung erweitert. Die richtige Funktionsweise dieser Modelle wird in Testszenarien nachgewiesen. Dabei fällt auf, dass aufgrund der Bauweise und Auslegung kleine Leistungen nicht umsetzbar sind. Abschließend werden Maßnahmen vorgeschlagen, um den nicht erreichbaren Leistungsbereich zu minimieren.The objective of this master thesis is to answer what kind of control is suitable for the HIL units of the planned "District LAB" and which control parameters must be set to efficiently implement the planned scenarios with as little deviation as possible from given load profiles. For this purpose, the hydraulic components are first modeled in MATLAB/Simulink using the Carnot toolbox according to the available documentation. Then, the transfer behavior of the heat exchangers is recorded and evaluated. Afterwards, the characteristic curves of the chokes and heat pumps are analyzed. In combination with the technical requirements, suitable control structures are developed for the individual components. For the heat exchanger between the HIL unit and the DHC, a feedforward control is developed to control the power and to decouple power control and temperature control. The temperature control is realized by a PI controller. This control structure will be transferred to the heat exchanger of HC and CC. To integrate the upstream reactors, the P and I values must be adapted. A virtual heat storage is implemented to control the heat pump, since the heat pumps can only operate at certain power levels. The variable power consumption is implemented in a virtual HIL unit. For the heat pump itself, a two-point controller combined with a pilot-controlled volume flow control is implemented. This is corrected by an integrator to compensate for deviations between the data sheet and the real components. The individual components are assembled into overall models of the HIL units and extended by a controller. The correct functioning of these models is verified in test scenarios. It is found that due to the construction and design, small outputs cannot be implemented. Finally, measures are proposed to minimize the unachievable performance range
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Ein digitaler Zwilling für die Versuchseinrichtung "District LAB" : Hintergrund, Ideen und aktuelle Aktivitäten : Ein Überblick
Get PDFDistrict heating systems are an important element for the success of the heat transition and the associated and necessary decarbonisation of the urban heat supply. Although the expansion and transformation of district heating grids towards decentralised supply solutions based on renewable energies or waste heat is accompanied by some advantages, there are also obstacles, especially economic ones. Digitalisation measures appear to be a promising way of counteracting these. The aim of the doctoral thesis presented in this paper is to develop a solution and to test these empirically at the experimental facility “District LAB”. The methods planned to achieve these goals are primarily the creation of a simulation model that contains all the essential thermo-hydraulic components and control structures of the test facility, as well as the transfer of this model into a digital twin that has access to its hardware. Furthermore, a solution regarding the predictive optimisation of the operation strategy is to be developed and subsequently tested. In the following, the planned methods and work steps are presented in detail and the first results of theoretical investigations are shown.Bundesministerium für Wirtschaft und Energi
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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