1,720,956 research outputs found
Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content
Get PDFThermal behaviors and combustion kinetics of Thai lignite with different SO3-free
CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under
oxygen environment at heating rates of 10, 30, and 50°C min−1 from
ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS)
methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal
degradation behaviors were observed in lignites with low (14%) and high
(42%) CaO content. Activation energy of the lignite combustion was found
to vary with the conversion fraction. In comparison with the KAS method, higher E values were obtained by the FWO method for all conversions considered.
High CaO lignite was observed to have higher activation energy than the low CaO coal
Improving solar dryer performance with automatic control of auxiliary heated air
No full textThis research aims to design and test automatic auxiliary heating unit for solar dryer cabinets to improve drying performance. The auxiliary heating unit utilizes an infrared furnace with cooking gas, a fin heat exchanger, and a blower. It is equipped with an automatic control system to regulate the temperature of the dryer. An agricultural product used in the experiment was fresh pineapple slides. The experimental test was divided into three cases; using (i) solar dryer, (ii) hot air dryer from the automatic auxiliary heating unit and, (iii) combined solar dryer with auxiliary heating unit. Temperature of the automatic auxiliary heating unit was controlled at 55.0 ± 3.0 °C and the air flow speed in the dryer cabinet was 1.5 ± 0.2 m/s. The thermal output from the automatic auxiliary heating unit was more than 2700 W. From the tests, it was shown that the drying time could be reduced to 12.5 h from 32 h, when the solar dryer was combined with the automatic auxiliary heating unit, compared to using only solar dryer. Dried pineapple products showed good quality. Comparative analysis of CIELAB color properties indicated low pigmentation. From a simple economic analysis, return on investment was less than 3.0 months. The use of automatic auxiliary heating units to the solar dryer enabled reduction in drying time and improved product quality
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
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