1,720,969 research outputs found
Pilot-scale experiences with aerobic treatment and chemical processes of industrial wastewaters from electronics and semiconductor industry
Full text linkTMAH is quaternary ammonium salt, consists of a methylated nitrogen molecule, and is widely used in the electronics industry as a developer and silicon etching agent. This substance is toxic and fatal if ingested. It can also cause skin burns, eye damage, and organ damage. Moreover, TMAH exhibits long-lasting toxicity to aquatic systems. Despite this known toxicity, the authorities currently do not provide emission limits (i.e., discharge concentrations) for wastewater by EU regulation. The current scenario necessitates the study of the processes for industrial wastewater containing TMAH. This work aims to present a successful example of the treatment process for the degradation of TMAH waste solutions of the E&S industry. Research was conducted at the pilot scale, and the process feasibility (both technical and economic) and its environmental sustainability are demonstrated. This process, which treats three exhausted solutions with a high concentration of toxic substances, is considered to be innovative
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
An effective new treatment of fluoride-containing sludge resulting from the manufacture of photovoltaic cells
No full textThe circular economy and maximization of environmental sustainability are increasingly becoming the vision and mission of companies competing in present-day global markets. In particular, in the energy sector, the transition from fossil fuels to renewable sources of energy has become the widespread mantra. One typical example is the deployment of devices which produce clean energy, such as solar photovoltaic panels and solar thermal panels, wind generators, tidal stream generators, wave power generators, etc. These are undoubtedly generating clean energy, but their manufacture creates hazardous by-products, the disposal of which results in increased environmental pollution. Chemical Vapor Deposition (CVD) is widely used in manufacturing of solar photovoltaic cells. In these processes, typically, crystalline silicon is precipitated from chlorosilanes, iodides, bromides and fluorides. Polluting by-products include deposition of a silicon film, formation of SiO2 powder and formation of toxic vapors of HF, SiH4 and PH3 . Usually, these gaseous products are eliminated in a central scrubber, whose unwanted by-product consists in large quantities of hazardous fluorine-containing sludge. This article concerns an effective and inexpensive detoxification of fluorinated sludge, developed by the authors during research into the sludge collected from the scrubber of a PV cell manufacturing plant located in southern Italy
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
Optimization of the process for the recovery of metals from waste: Circular economy approach in the galvanic industries
No full textThe article focuses on solvent extraction to recover nickel (Ni) and copper (Cu) from leaching solutions obtained by dissolving galvanic sludges with residual effluents of the metal processing industry. D2EHPA diluted in Metryl GI060 was tested as the organic solvent. The first experiments were performed on synthetic solutions to define and optimize the solvent extraction processes. The optimal conditions were subsequently tested to treat real solutions containing Ni and Cu from the leaching of galvanic sludge. The results showed that the real solution behaves differently from the synthetic ones, so new optimization tests were added to maximize Cu extraction from Ni. Under the optimized conditions (pH 4.5, 15% v/v D2EHPA and aqueous/organic (A/O) equal to 2), the extraction yield for Cu was 91%, whereas it was 1% for Ni. The organic solution was subjected to stripping with sulfuric acid (1 M, A/O volume ratio equal to 1). The stripping yield was 99.7%. Two phases were obtained: CuSO4aqueous solution and the organic phase with D2EHPA/Metryl GI060, which can be recirculated to treat galvanic sludge. NaOH precipitated more than 98% of Ni from the solvent extraction raffinate. The final solid was composed of 4.31 wt% Cu and 39.58 wt% Ni. Finally, a flowsheet with a mass balance for treating 1 tonne of galvanic sludge was proposed
Zero-liquid discharge treatment of wastewater from a fertilizer factory
Full text linkThis article describes the improvement of wastewater treatment in a fertilizer plant located in Central Italy (municipality of Vasto). In this facility, water is used for the removal of dust and fluorinated gases from the air. The resulting wastewater contains fluorides and phosphates in hazardous forms. Its treatment ordinarily does not result in a Zero-Liquid Discharge (ZLD) process. To achieve this purpose, several reagents were tested, focusing on the correlation linking pH, type of reagent and the effect on the separation of fluorides and phosphates from the wastewater. It was eventually found, and explained with a model, that hydrated lime at pH = 12 was so effective as a precipitating agent that phosphate and fluoride separation reached a value of 99.9%, thus allowing for reuse of the water in the plant process. Furthermore, phosphates and fluorides precipitated in a non-hazardous form, so that the material could also be recycled. In synthesis, wastewater treatment of the fertilizer plant was upgraded so that it became a ZLD process coupled with the recovery and recycling of fluorides and phosphates
Selective Recovery of Gold from E-Waste Recycling Plants’ Waste Fractions: Waste-to-Resource Transition
Full text linkElectronic waste grows globally at a rate of 5% annually, which makes electronic waste recycling (WEEE recycling) an urgent task aimed at achieving (i) environmental protection and (ii) the preservation of mineral resources through the re-introduction of strategic metals into the market. As it turns out, WEEE recycling produces further waste, called WEEE secondary waste, which still contains valuable metals such as gold, silver, and copper. This study assessed the economic viability of recovering these metals and identified the most promising targets and approaches. WEEE secondary waste produced at a plant in southern Europe was sampled and examined for this purpose. The study methods included an ANOVA (analysis of variance) and an OCCP (orthogonal central composition plan). Over 90% gold, silver, and copper extraction was achieved with hydrochloric acid leaching in sodium hypochlorite with sodium chlorite as an oxidizing agent at 60 °C. The significance of the variation in the response for each factor, calculated using the Yates algorithm, demonstrates that by excluding sodium chloride and optimizing the doses of hydrochloric acid and sodium hypochlorite, gold can be selectively recovered through the leaching process. The scenario of HCl (2.5M)/NaClO (5%) leaching results in the maximum extraction effect of Au (91.6%) at the lowest concentrations of Ag and Cu (37–44%)
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