1,721,029 research outputs found
Crack-bridging ability of organic coatings on concrete
No full textA testing apparatus for measuring crack-bridging ability is introduced. For demonstration purposes, the application of this apparatus for the crack-bridging measurements of four commercial coating systems with markedly differing natures and mechanical properties is discussed
The importance of adhesion control in crack-bridging measurements
No full textThe crack bridging ability (CBA) of two commercial coatings based on polyurethane resins was studied as specified in the European Standard EN test method. The test pieces of concrete blocks were used for the CBA evaluation at room temperature and the roughness index of the substrate was not measured. The results show that CBA resulted at lower values of displacement in the first coating than in the second one, the CBA values between 0.8 mm and 2.4 mm were observed. The results obtained at low temperature of 269 K show hat the mechanical response of the coating differs at ambient temperature as the low temperature causes the material to harden. The CBA values ranged between 0.42mm and 0.66 mm for the test performed at ambient temperature, and between 0.52 mm and 0.55 mm for the low temperature tests
System for ammonia removal from anaerobic digestion and associated ammonium sulfate production: Simulation and design considerations
No full textA side-stream ammonia stripping system coupled with a full-scale anaerobic digestion plant is considered. The system is based on an ammonia stripping unit (thin film evaporator, TFE), a Venturi scrubber and a reactive absorption column. A portion of the sludge treated in the digesters is continuously withdrawn and transferred to the TFE, where ammonia is stripped through a biogas stream. The ammonia rich biogas is then treated with a sulfuric acid/water solution in the Venturi scrubber and in the absorption column, with production of an ammonium sulfate solution, which is stored in a tank until utilization as a fertilizer. The aim of this paper is to provide a comprehensive engineering framework supporting the design of a full-scale ammonia stripping system with associated ammonium sulfate production, to be coupled with pre-existing anaerobic digestion plants. On the one hand, an analytical equation is proposed for the simulation of ammonia desorption and the design of the ammonia stripping unit as a function of the selected operating conditions of flowrate, temperature and pH. On the other hand, corrosion issues affecting the storage tank are studied. Corrosion tests, carried out on a selected paint system, demonstrate no development of coating degradation or disbonding, even if local damage occurs in the film. Thus, guidelines to avoid corrosion are given
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
Process of ammonia removal from anaerobic digestion and associated ammonium sulphate production: Pilot plant demonstration
No full textA process for the continuous extraction of ammonia from anaerobic digesters is proposed. In this process, a portion of the sludge treated in the digesters is continuously withdrawn and transferred to a thin film evaporator (TFE) unit, where the ammonia is stripped through a biogas stream. The ammonia-rich biogas is treated with a sulfuric acid/water solution in a reactive absorption unit, with production of ammonium sulphate. The chemistry of a CH4/CO2/NH3 gas phase in thermodynamic equilibrium with a liquid sulfuric acid/water solution is investigated theoretically, with focus on the simultaneous absorption of CO2 and NH3 into the liquid phase. Pilot plant experimental data confirm the theoretical results. Further pilot plant experimental results obtained during on-off cycles of the stripping equipment demonstrate that, when the TFE unit is off, ammonia concentration in the digestate rises quickly, while, when the stripping equipment is turned on again, ammonia concentration drops down. On average, during the 180 days of pilot plant experimentation, 4.1 g N–NH4 per kg of sludge fed to the digester, i.e. 19.3 g N–NH4 per kg of total solids (TS) fed to the digester, are stripped from digestate and recovered as ammonium sulphate, demonstrating the feasibility of the proposed concept
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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