1,720,959 research outputs found
Iš anksto įtemptais bazalto pluošto strypais armuotų lenkiamųjų betoninių elementų elgsenos analizė
Get PDFIn general, prestressed concrete (PC) is by far one of the most economical concrete construction techniques, but at the same time, it requires specific knowledge of the properties and behavior of this material. Precompression of the concrete by transferred prestressed force flexural stiffness can be increased and the main issue – cracking might be eliminated, correspondingly. Based on the development progress PC is widely being utilized in the construction of the structures for transport and energy sectors (bridges, viaducts, gasholders, reactors, oil&gas tanks, etc.). It has been used in order to store potentially dangerous materials during operation and to resist dynamic effects. However, even in PC case cracking appears, and it is common that it causes corrosion of conventional reinforcement. Finally, it influences the maintenance of existing infrastructure.
Within this research, the author develops the particular subject of concrete – application of new composite material – basalt fiber reinforced polymer (BFRP) to be used for prestressed concrete structures considering subsequent loading stages (stretching at the bulkheads, prestress transfer to concrete, application of service load, etc.). In order to design PC structures, it is significant to estimate effective prestress force with respect to the time-dependent process of concrete and reinforcement. In accordance with design codes requirements, typical formulas from regular concrete structures (RC) are to be used for the estimate of serviceability conditions of flexural PC members. However, a complete review of prestress losses and serviceability shall be employed in order to avoid errors in the structural prognosis of the PC structures with non-conventional composite reinforcement.
Unlike other composites, experimental test work and calculation methods have yet to be developed for BFRP reinforcement in order to determine stress relaxation behavior. Currently, this phenomena is not fully documented in the literature. Based on this, the author approached an innovative stress relaxation test method to describe the effect of stress relaxation and its impact on the final value of the effective prestress force. Full-scale testing beams were tested in order to evaluate the impact of prestress level (degree) to the flexural stiffness of concrete beams internally prestressed with BFRP bars.
The dissertation is structured within the introduction, three main chapters, verification of the results, the lists of references and author’s publications on the subject of the dissertation.
The topic of the thesis has been discussed in 9 articles: 3 – in the journals with an Impact Factor, 5 – in scientific journals of other international databases and 1 in the conference proceedings referred by the Clarivate Analytics Web of Science
Calculating the carrying capacity of flexural prestressed concrete beams with non-metallic reinforcement
No full textThe article reviews moment resistance design methods of prestressed concrete beams with fibre-reinforced polymer (FRP) reinforcement. FRP tendons exhibit linear elastic response to rupture without yielding and thus failure is expected to be brittle. The structural behaviour of beams prestressed with FRP tendons is different from beams with traditional steel reinforcement. Depending on the reinforcement ratio, the flexural behaviour of the beam can be divided into several groups. The numerical results show that depending on the nature of the element failure, moment resistance calculation results are different by using reviewed methods. It was found, that the use of non-metallic reinforcement in prestressed concrete structures is effective: moment capacity is about 5% higher than that of the beams with conventional steel reinforcement.
Article in Lithuanian
Lenkiamų iš anksto įtemptų gelžbetoninių sijų su neplienine armatūra normalinio pjūvio laikomosios galios skaičiavimas
Santrauka
Straipsnyje aptarti lenkiamųjų iš anksto įtemptų gelžbetoninių sijų su neplienine (angl. non-metallic) arba kompozitine armatūra normalinio pjūvio laikomosios galios skaičiavimo metodai. Neplieninė armatūra iki pat lenkiamų gelžbetoninių ar iš anksto įtempto gelžbetonio elementų laikomosios galios netekimo išlaiko tamprumo savybes. Šia armatūra armuotų sijų, lyginant su tradicine plieno armatūra, elgsena skiriasi. Galimi keli kompozitine (FRP) armatūra armuotų lenkiamųjų elementų suirimo atvejai. Skaičiavimo rezultatai rodo, kad priklausomai nuo elemento suirimo pobūdžio, remiantis straipsnyje aptartais metodais, normalinio pjūvio laikomosios galios skaičiavimų rezultatai skiriasi. Nustatyta, kad neplieninės armatūros naudojimas iš anksto įtemptose konstrukcijose yra efektyvus: laikomoji galia gali būti apie 5 % didesnė už sijų su įprastine plienine armatūra laikomąją galią.
Reikšminiai žodžiai: anglies pluošto armatūra, įtemptasis gelžbetonis, pusiau pusiausviro suirimo metodas, Collinso betono modelis
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
