1,720,953 research outputs found
Post Combustion Carbon Dioxide Capture: Exploration of Prospective Solvents
No full textGlobal warming is one of the toughest challenge, humanity is currently facing. Temperature of the Earth’s surface is influenced through the process of absorption of heat radiation by greenhouse gases, like H2O, CO2, CH4 etc. In the prevailing state of technology, huge CO2 are thrown from thermal power plant installations, natural gas purification, and refinery off gases. Carbon dioxide gas being a greenhouse gas needs to be controlled in its emission from various point sources, which is under the purview of revamping current technology as a benign one. Different post-combustion CO2 capture techniques are available like, absorption (physical and chemical), adsorption (physical), membrane, and cryogenic separation. Among them, chemical absorption-desorption is the most mature and suitable technology available so far. In chemical absorption process, solvent plays most vital role, which is weighed in terms of its CO2 absorption capacity, absorption rate, energy penalty for regeneration, availability, degradation resistance, toxicity etc. Hence, selection of solvent as CO2 absorbent seeks paramount attention.
Various limitations including high regeneration energy, higher vapour pressure, limited CO2 loading capacity of common alkanolamines solvents like monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), 2-amino-2-methyl propanol (AMP) and their blends, necessitated the exploration of alternative CO2 absorbing solvents. Newer solvents having different spatial arrangements have been utilized to study the effect of their molecular structure in CO2 absorbing property. Among them, 2-diethylaminoethanol (DEAE) and 1-(2-hydroxyethyl)piperidine (HEP) and their blends with piperazine (PZ) performed as better CO2 absorbents in the screening of solvent experiments followed by detail solubility studies.
Amino acid salts are very promising because of their negligible vapour pressure, lesser toxicity, high absorption capacity and rate, thermal stability etc. Pottasium salt of arginine (KArg) and lysine (KLys) revealed the highest apparent rate and capacity and potassium salt of 2-aminoisobutyric acid (KAmib) possesses moderate apparent rate and high capacity in the screening experiments among amino acid salts. KAmib, being a sterically hindered primary amino acid (similar structure like 2-amino-2-methyl-1-propanol (AMP)) salt; forms unstable carbamate thus possesses high capacity of CO2 absorption and lower regeneration energy. Due to high apparent rate constant of KArg, KLys and PZ compounds, they were used as rate promoters to enhance the CO2 absorption rate of KAmib solvent successfully.
Absorption of CO2 in amine based solvent is a regenerative and chemical absorption process. Regeneration energy varies depending upon the solvent formulation and is directly related with enthalpy of CO2 absorption of that solvent. Enthalpy of CO2 absorption is measured through calorimetric experiments. Interestingly, enthalpy of CO2 absorption could be precisely predicted from thermodynamic model using equilibrium CO2 solubility data. Since no experimental or predicted enthalpy of CO2 absorption in DEAE, HEP and their blends with PZ are available in the open literature, prediction of enthalpy from activity coefficient based model on solubility seems to be a significant contribution of this dissertation.
Limitation of regenerative absorption process could be overcome by using some water soluble organic solvents (acetone and tetrahydrofuran (THF)) having very low dielectric constant compared to water at low temperature for solvent regeneration. Solvent regeneration by this technique is only possible when the CO2 rich solution contains only bicarbonate and carbonate ions; not carbamate ions. CO2 rich DEAE solution was used for the study of CO2 regeneration using organic solvents like acetone/THF. This is one of the directional aspects of the present dissertation, which deserves further attention.
Besides experimental study to explore a suitable solvent for gas treating process, thermodynamic modelling plays important role to complement experimental results. Deshmukh and Mather model, one of the efficient activity coefficient based models describing multi-component and multi-phase fluid phase equilibria was used to correlate the vapour-liquid equilibrium data generated in the work. Liquid phase speciation for both CO2 loaded single and blended amine solutions, and enthalpy of CO2 absorption were predicted effectively using the developed model in MATLAB platform.
For developing Thermodynamic equilibrium and kinetic rate models, physicochemical parameters of those amine based solvents are required. In view of this, physicochemical properties like density and viscosity of single and blended alkanolamines over wide range of temperature, relative amine compositions were generated and correlated using thermodynamic framework, which are useful contribution to the design database of sour gas treating process
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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