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Chiarificazione delle acque di raffreddamento nell'industria del vetro: messa a punto del processo e dimensionamento dell'impianto
No full textTreatment of cooling waters containing glass from glass manufacturing plants for recycling
Full text linkThe removal of the fine particles of glass in suspension in cooling waters having different solids content has been conducted by flocculation with two different additives, sedimentation and filtration. The process proposed allows the recycling of these waters; it may suggest a more efficient management and use of water in the glass industry.
Among the different types of additives investigated, a particular type of polyacrylamide has shown the best results, both in the capacity of clarification and sedimentation of the fine suspended particles, and in the feasibility of the filtration process
Catalytic upgrading of pyrolytic oils over HZSM-5 zeolite: behaviour of the catalyst when used in repeated upgrading-regenerating cycles
No full textThe behaviour of HZSM-5 zeolite in the upgrading of a wood pyrolysis oil produced in the ENEL fast-pyrolysis plant located in Bastardo, Italy, was studied in repeated upgrading-regenerating cycles. The HZSM-5 zeolite performs a catalytic activity by its acidic sites that, through a carbonium ion mechanism, promote deoxygenation, decarboxylation and decarbonylation of the oil constituents, as well as cracking, oligomerization, alkylation, isomerization, cyclization and aromatization. As a consequence of the catalytic process, coke and tar were also obtained as undesirable by-products. The continued regeneration of the zeolite, consisting of removal of the coke deposits by air at 500 °C, reduced the effectiveness of the catalyst in converting biomass pyrolysis oils to an aromatic product, until an irreversible deactivation was observed. By the analysis conducted on the catalyst it was possible to assess that the loss of activity is mainly connected to the disappearance of a significant amount of acidic sites, mainly the stronger ones, due to the thermal cycling to which the catalyst was submitted. Even if the regeneration was conducted at 500 °C, localized raisings of temperature above 500 °C due to the combustion of coke may have caused dehydroxylation of the Bronsted acid sites that predominate in zeolites activated at 500 °C with formation of Lewis acid sites. Thus, the active acid sites in the upgrading reactions are presumed to be preferentially Bronsted acid sites, which were gradually deactivated by the repeated regeneration treatments
Treatment of olive oil industry wastes
No full textThe waste products derived from olive oil extraction are an aqueous effluent (vegetation water) and a solid residue, mainly containing the olive skin and stone (olive husk). Biological purification of the vegetation water is particularly difficult because it contains solids in suspension, and a high concentration of polluting organic compounds and mineral salts. In addition, since the recovery of oil by solvent extraction from the olive husk is no longer a profitable process, the olive husk has become a waste product that must be disposed of. In this work, samples of vegetation water (VW) from olive oil mills were separated by evaporation into an aqueous liquid (80-90% of the initial volume), that could then be purified by a traditional biological process, and a residue in which about 98% of the organic load was concentrated. The properties of the concentrated VW residue and of the olive husk suggested the possibility of using a mixture of the two as an efficient fuel to provide the heat for the evaporation stage. (C) 1998 Elsevier Science Ltd. All rights reserved
Thermal Behaviour of Blends of Polycarbonate and Liquid-Crystal Polymers: A D.S.C. Study
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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
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