1,720,960 research outputs found
Modeling of cross flow hollow fiber ultrafiltration for treatment of effluent from Railway Workshop
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Modeling aspects of membrane-based industrial wastewater treatment
No full textMembrane-based separation processes have been widely used for the treatment of industrial effluent streams, considering their wide range of applicability and easy scale-up. The effluent streams usually consist of a mixture of interacting as well as noninteracting components. The physical and transport properties of these constituents, viz., the diffusivity properties of the cake layer deposited over the membrane surface, etc., are very important for modeling and cannot be determined experimentally. Lab scale filtration data can be utilized to determine these parameters for specific contaminants. The modeling of membrane performance has been carried out extensively focusing mainly on predicting the permeate flux. However, prediction of the quality of the filtrate is also very important considering the stringent requirement of the quality of the treated effluent. This chapter mainly focuses on various aspects of modeling of membrane-based separation process used for the industrial applications. This will be useful in predicting the efficiency and throughput of the filtration system and hence aiding in the scaling up
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
Modeling of solution thermodynamics: A method for tuning the properties of blend polymeric membranes
No full textThermodynamics of polymer blends are modeled and ternary phase diagrams are plotted for various blend compositions using Flory-Huggins theory for polymer solutions. Equations of spinodal curve and plait point for the quaternary systems are derived based on solution thermodynamics. Binodal curves are calculated by minimizing Gibb's free energy for blend system, poly(acrylonitrile) and poly(urethane). Effects of polymer molecular weight and interaction parameters on the phase diagram are quantified. The published data of membrane transport characteristics are correlated with the modeled phase diagram and validated using FESEM and pore-diameter analysis. The reason for increase in the permeability of blend membranes is established with structural changes with the possible formation of hydrogen bond and justified by the infrared spectra analysis of the blend membranes
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
Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes
No full textAn extensive study of thermodynamics and kinetics of non-solvent induced phase separation was carried out for poly(vinylidene fluoride)/solvent/water system for four different solvents. Literature available on semicrystalline polymers was mostly based on experimental cloud points, obtained to a narrow range of polymer concentration (‹10 wt%), much less than the working range for membrane preparation (20–25 wt%). Aim of this work was to model the thermodynamic phase diagram using extended Flory–Huggins theory which was used as a tool, along with the kinetic data to obtain tailor-made membranes with desired morphology and properties. Interaction parameters involving solvent, nonsolvent, and polymer played an important role to tune the porosity of the membrane. Thermodynamic calculation showed solvent N,N-dimethyl acetamide resulted in the most porous membrane (permeability 5.4 × 10−11 m Pa−1 s−1) followed by N,N-dimethyl formamide (permeability 4.2 × 10−11 m Pa−1 s−1), N-methyl pyrrolidone (permeability 3.8 × 10−11 m Pa−1 s−1), and acetone (impermeable to water even at 1380 kPa), which was the densest one. Prepared membranes were characterized in terms of surface morphology, molecular weight cut-off, tensile strength, pore volume distribution, crystallinity, and surface roughness, which were correlated to inferences based on thermodynamic and kinetic calculations. POLYM. ENG. SCI., 58:1062–1073, 2018. © 2017 Society of Plastics Engineer
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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