1,720,958 research outputs found
An application of the photogrammetric method for a formation study of the coarse droplets in steam turbine
No full textPráce se zabývá experimentálním studiem vzniku hrubých kapek způsobujících erozi lopatek posledních stupňů parních turbín. Pro experiment bylo simulováno prostředí parní turbíny pomocí experimentální dýzy a k měření se použila fotogrammetrická metoda. Pro vyhodnocování je nastíněn vhled do problematiky segmentace obrazu.This paper deals with an experimental study of coarse droplet formation causing erosion at the last stage of steam turbines. An environment of the steam turbines was simulated by the utilization of an experimental nozzle. The photogrammetric method was used for the measurement and the image segmentation was presented for the future study
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
Study of the formation of CO2 hydrates and their further use in the long-term accumulation of electrical energy
Full text linkTato bakalářská práce se zaměřuje na studium hydrátů CO2.Popisuje vlastnosti hydrátů a reaktory pro jejich výrobu. Pojednává o látkách podporujících tvorbu hydrátů CO2 a o možnostech jejich následného využití k záchytu a ukládání CO2. Praktická část se věnuje studiu tvorby hydrátů CO2 bez a s promotorem jejich tvorby na experimentální trati FS ČVUT.This bachelor thesis focuses on the study of CO2 hydrates. It describes the properties of hydrates and reactors for their production. It discusses substances supporting the formation of CO2 hydrates and the possibilities of their subsequent use for CO2 capture and storage. The practical part deals with the study of the formation of CO2 hydrates without and with the promoter of their formation on the experimental track of FS CVUT
Utilizing the Leidenfrost effect to influence water film breakup in steam turbines
No full textBakalářská práce se zabývá studií využití lokálního ohřevu a vzniku Leidenfrostova jevu za účelem odtržení vodního filmu, tvořícího se na posledních stupních parních turbín, způsobujícího erozi lopatek parních turbín. Práce obsahuje rešeršní část popisující funkci parních elektráren, mechanismus eroze lopatek a možné ochrany proti ní. Praktická část obsahuje návrh a realizaci experimentu, který využívá podtlaku k vytvoření ideálních podmínek pro vznik Leidenfrostova jevu a analýzu dat s vyhodnocením.The bachelor thesis deals with the study of the use of local heating and the Leidenfrost phenomenon in order to break off the water film formed on the last stages of steam turbines, causing erosion of the steam turbine blades. The thesis contains a research section describing the function of steam power plants, the mechanism of blade erosion and possible protection against it. The practical part includes the design and implementation of an experiment that uses vacuum to create suitable conditions for the Leidenfrost phenomenon and data analysis with evaluation
The experimental study of the CO2 hydrates formation
Full text linkClathrate hydrates, complex molecular formations with significant potential in the energy sector, are the focal point of this thesis. These compounds are increasingly recognized for their versatile applications, including carbon capture and storage, renewable energy sources, water desalination, and gas mixture separation. In the context of contemporary environmental challenges, particularly global warming, clathrate hydrates, especially those in the seabed, have garnered attention due to the risk of methane release—an extremely potent greenhouse gas—into the atmosphere. This thesis aims to comprehensively review the existing body of knowledge surrounding clathrate hydrates, exploring their potential applications and the advancements in reactor technology that facilitate their study and utilization. A significant portion of this research is devoted to the construction and implementation of an experimental setup designed to observe and analyse the crystallization process of CO2 hydrates. Through detailed observation and documentation of this process, the study seeks to deepen the understanding of hydrate formation dynamics. This insight is crucial for harnessing the potential of clathrate hydrates in various industrial applications and for mitigating their environmental impact, particularly in relation to climate change and greenhouse gas emissions. By bridging gaps in current knowledge and exploring innovative experimental methodologies, this thesis contributes to the broader scientific understanding of clathrate hydrates, underscoring their significance in both environmental and energy contextsClathrate hydrates, complex molecular formations with significant potential in the energy sector, are the focal point of this thesis. These compounds are increasingly recognized for their versatile applications, including carbon capture and storage, renewable energy sources, water desalination, and gas mixture separation. In the context of contemporary environmental challenges, particularly global warming, clathrate hydrates, especially those in the seabed, have garnered attention due to the risk of methane release—an extremely potent greenhouse gas—into the atmosphere. This thesis aims to comprehensively review the existing body of knowledge surrounding clathrate hydrates, exploring their potential applications and the advancements in reactor technology that facilitate their study and utilization. A significant portion of this research is devoted to the construction and implementation of an experimental setup designed to observe and analyse the crystallization process of CO2 hydrates. Through detailed observation and documentation of this process, the study seeks to deepen the understanding of hydrate formation dynamics. This insight is crucial for harnessing the potential of clathrate hydrates in various industrial applications and for mitigating their environmental impact, particularly in relation to climate change and greenhouse gas emissions. By bridging gaps in current knowledge and exploring innovative experimental methodologies, this thesis contributes to the broader scientific understanding of clathrate hydrates, underscoring their significance in both environmental and energy context
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
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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