1,720,959 research outputs found
Systematic exploration of direct solar absorption potential to enhance direct contact membrane distillation
Get PDFIncreasing concerns about global freshwater scarcity and the growing demand for renewable energy are stimulating the exploration of innovative technological solutions for sustainable water management. Thanks to an experimentally validated model, here we systematically assess the effectiveness of distributed solar heat in enhancing the productivity of direct contact membrane distillation (DCMD) for seawater desalination. The proposed study investigates the impact of various configurations and operating parameters, analyzing more than 1000 cases, focusing on optimizing heat and mass transfer, hence water flux, in counter-current and co-current channel designs. Our findings indicate that integrating solar heat can significantly improve DCMD performance, with productivity enhancements potentially exceeding 200%, especially at low cross-flow rates, by alleviating temperature polarization and enhancing vapor flux. The detailed analysis further reveals that the counter-current configuration consistently outperforms the co-current design under optimal conditions, achieving higher water fluxes and reduced polarization effects. Moreover, sensitivity studies underscore that fine-tuning channel dimensions and flow parameters is critical for maximizing energy efficiency and ensuring robust desalination performance. The results highlight the potential of solar-powered MD systems to provide sustainable and cost-effective freshwater solutions, particularly for off-grid and remote areas. By optimizing solar heat utilization and MD configurations, this study advances both theoretical understanding and practical applications in water desalination, promoting energy efficiency, operational cost reduction, and environmental sustainability
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
The CARMEn project: A sustainable and circular brine treatment chain
Get PDFThe increasing demand for water and critical minerals is currently largely met through linear processes, such as desalination and saltworks, which generate highly saline waste streams typically discharged to the sea. These brines, however, are rich in valuable components. The Italian-funded CARMEn project proposes a circular approach to valorize such streams by producing magnesium hydroxide, freshwater, and energy through an integrated treatment chain. As proof of concept, real reverse osmosis (RO) brine and saltworks bitterns were processed at laboratory scale through a sequence of nanofiltration, reactive precipitation, softening, electrodialysis with bipolar membranes, membrane distillation, and reverse electrodialysis. Experimental data supported the development of a preliminary techno-economic analysis to assess the viability of a pilot plant targeting 50 tons/year of Mg(OH)2. Results show that feed composition and operating pH strongly influence performance. Bitterns, with Mg2+ concentrations ~20 times higher than RO brine, led to the lowest CAPEX and EnEx and enabled >99.7 % product purity, but required external water input, reducing circularity. RO brine and NF retentate achieved full circular operation without external inputs, though with higher costs and slightly lower product purity (approximately between 85 and 93 %). Across all scenarios, EDBM and MD dominated energy demand, but coupling MD with waste heat reduced power consumption lowering the levelized cost of Mg(OH)2
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Concentration of phycocyanin and coffee extracts in aqueous solutions with osmotically-assisted membrane distillation
Get PDFOsmotic membrane distillation (OMD) is a dewatering process that exploits combined temperature and osmotic pressure gradients to drive water vapor fluxes under mild operation conditions. In this study, the feasibility of OMD is evaluated for the concentration of phycocyanin and coffee extract solutions, with the goal to safeguard the quality of the extracts. Different feed solution temperatures were studied, namely, 35 °C, 45 °C, 55 °C, while keeping a concentration of 4 M CaCl2 in the extraction solution. The target concentration factor was set to 4, equivalent to a water recovery rate of 75 %. The results suggest that a temperature equal to or below 45 °C should be chosen for the concentration of phycocyanin to prevent degradation and to minimize fouling, while higher temperatures may be used for the recovery of the coffee extract. The combined gradients provided water fluxes around or above 4 L m−2h−1 with both extracts under relatively mild conditions, even at high concentration factors. Qualitative membrane fouling inspection was corroborated by estimating the fraction of productivity lost due to fouling, which was larger for higher feed temperatures and for the phycocyanin extracts, and had values between roughly 20 and 70 %. Results also suggest that the quality of the extracts was maintained, based on the measured purity and content of the target compounds in the concentrated solutions. Specifically, no trace of extraneous compounds was found, and no salt passage was observed from the extraction solution to the feed solution, suggesting that OMD has the potential to concentrate sensitive components
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