1,720,965 research outputs found
COMPLETE BENEFICIATION OF LEUCITE BY THERMAL-TREATMENT
No full textHigh-temperature roasting of leucite in the presence of CaCl2 gives rise to a reaction that results in almost complete recovery of its potassium content as KCl. A solid residue consisting mainly of anorthite and silica is also obtained; this could be used as raw material for the production of hydraulic binders. The process is of economic interest because of the relatively low temperatures involved and especially the low cost of the reagents employed, since these find no other valid industrial application at present. Potassium chloride, cordierite and silica are obtained if MgCl2 is used instead of calcium chloride
Application of thermal analysis techniques to a sample of Red Mud, a byproduct of the Bayer process
No full textLisciviazione del solfuri con solfato ferrico - Cinetica di ossidazione del solfuro di zinco
No full textPyrolysis of automotive shredder residues: a lumped kinetic characterization
No full textA lumped kinetic model for the pyrolysis of industrial wastes of unknown chemical composition is developed. The model is applied to the pyrolysis of automotive shredder residues (ASRs), studied by means of thermogravimetric and calorimetric analyses, in isothermal and non-isothermal conditions
Thermal behaviour of mixtures of an alunite ore with K2CO3, CaCO3 and Ca(OH)2
No full textThe thermal behaviour of alunite/K2CO3, alunite/CaCO3 and alunite/Ca(OH)(2) mixtures has been established. DTA coupled with XRD analysis has allowed appraisal of the main reactions that occur when the mixtures are roasted up to about 1000 degrees C. The main products of roasting are K2SO4, CaSO4 and other sulphur compounds and aluminates which retain the SO3 deriving from the alunite. The products are formed between 700 and 800 degrees C, The aim of the work was to assess the feasibility of a thermal process for use in the case of certain kaolin deposits whose exploitation is impossible at the present time because they are contaminated with alunite (KAl3(SO4)(2)(OH)(6)) This mineral causes great difficulty when attempting to use these kaolin ores because kilning drives off SO3 which corrodes the furnaces and is environmentally harmful. The K2SO4 and CaSO4 produced by roasting the indicated mixtures can be leached with water and dilute HCl respectively and the former can be used as fertiliser. The leaching residue, with its reduced sulphur content, can then be employed by the ceramics and building industries. (C) 1997 Elsevier Science B.V
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
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
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