1,720,972 research outputs found
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
Process Intensification in Crystallization: Submicron Particle Generation Using Alternative Energy Forms
Full text linkCrystallization is one of the oldest separation and product formation techniques that continues to be in use today. Despite its long history, it only started to develop significantly in the past few decades. In this thesis, the application of Process Intensification in crystallization is investigated. Process Intensification is a set of often radically innovative principles in process and equipment design, which can bring significant benefits in terms of process and chain efficiency, capital and operating expenses, quality, wastes, process safety, etc. Alternative energy forms as basic elements of Process Intensification are investigated by applying electric fields and plasma technology in crystallization processes. Three main topics are discussed in this thesis: a) Submicron-sized and nano-sized particles can have beneficial product properties compared to conventionally sized crystalline products. Electrospray Crystallization, an advanced crystallization technique can serve as a tool to produce such submicron-sized particles. In this thesis, it was investigated whether electrospray crystallization can be used to produce 1. energetic materials with a reduced sensitivity and 2. submicron-sized pharmaceutical compounds for improved dissolution and absorption. Electrospray crystallization of a solution is an integrated process of spraying and crystallization that uses a high voltage to produce a fine aerosol of droplets in the micron-size range. During the process, the emitted solvent droplets evaporate and a droplet disruption process (Coulomb-fission) occurs, which creates even smaller droplets. Due to solvent evaporation, eventually supersaturation is achieved and crystals of submicron particles can commence. Electrospray crystallization is an efficient, cost-effective and simple method for the production of submicron-sized crystals, but it suffers from a low production rate and it could be challenging to scale up. In this thesis, the process parameters for establishing a stable jet for producing submicron-sized particles were determined. The operation window to establish a continuous jet and produce submicron-sized crystals is relatively narrow, but experimentally feasible to maintain. Energetic crystals of RDX and HMX were produced with a mean size of around 500 nm by electrospray crystallization. The produced explosive crystals were tested for impact and friction sensitivity. The samples were remarkably insensitive to friction stimuli, while an insignificant difference for the impact sensitivity was observed. With similar process parameters, submicron-sized crystals of a poorly water-soluble active pharmaceutical ingredient, niflumic acid, were produced. In the absence of excipients, for the case of the submicron-sized niflumic acid, no significant difference was shown in the dissolution profile compared to the conventional one. However, upon mixing the excipients, D-Mannitol and Poloxamer 188, with the submicron-sized niflumic acid, the dissolution rate of the drug was enhanced. Thus, it is possible to increase the bioavailability of drugs by drastically reducing the crystal size, while preventing their aggregation by using the proper excipients. b) Plasma Crystallization is a new crystallization technique, in which an atmospheric pressure cold ionized gas is used to generate submicron-sized crystals. This novel type of plasma, the Surface Dielectric Barrier Discharge (SDBD), is a plasma made by several self-terminating microdischarges on a surface. A nebulizer system sprays the solution aerosol into the plasma with the help of a carrier gas. The plasma charges and heats the droplets. Upon evaporation Coulomb-fission occurs, supersaturation increases, and nucleation and crystal growth take place within the small, confined volume offered by the small droplets. Compared to the electrospray crystallization, much higher production rates can be achieved. The energetic material, RDX, and the active pharmaceutical ingredient, niflumic acid, and its excipient, Poloxamer 188, were produced by plasma crystallization with a significant size reduction compared to the conventional products. While there was no measurable change in the sensitivity of RDX, a substantial increase in the dissolution rate of the submicron niflumic acid crystals was observed in the presence of the plasma-made excipient. c) The effect of a constant high electric field was investigated during the cooling crystallization of isonicotinamide in 1,4-dioxane (Electrostatic Crystallization). Two experimental setups were built in order to examine the electric field effect, with a focus on crystal polymorphism control. An inhomogeneous electric field was generated in a controlled crystallization environment. A Crystalline station with an on-board camera system offered in situ investigation of the experiments. A more homogeneous electric field was generated in a different setup, but without a precise temperature control. Image analysis from the Crystalline station experiments showed that the applied electric field induced fluid motion of the solution due to the Lorentz-force acting on the isonicotinamide molecules in solution. This induced fluid dynamics was further visualized by using a suspension of the isonicotinamide-1,4-dioxane system. Image analysis also showed that the nucleation was localized to the anode, and crystals were formed only on the anode surface. The electric field generated a concentration gradient, with the highest solution concentration around the anode. The crystal growth rate was also measured with the help of the on-board camera system. It was found that in the presence of the electric field, the growth rate of the isonicotinamide crystals formed on the anode is 15 times higher than in the absence of the electric field. From this crystal growth rate increase, the local supersaturation ratio increase was estimated at the anode, and found to be at least 2.5 times higher in the presence of the electric field, than in the absence. In the absence of the electric field, the metastable, chain-like form I isonicotinamide was crystallized in both experimental setups. In the inhomogeneous electric field, both form I and form II of isonicotinamide were crystallized. By applying a more or less homogeneous, constant electric field during the crystallization, only the stable form II was formed. In addition, concerns regarding the reliability of standard small-scale sensitivity tests methods for submicron-sized explosives were discussed in this thesis, since the obtained results for the produced explosive materials are questionable. In order to test the quality of the produced submicron-sized energetic materials, a series of small-scale sensitivity tests were carried out. Impact and friction sensitivity tests and ballistic impact chamber test were performed to determine the product sensitivity. Concerns were found with the standard friction and ballistic impact chamber sensitivity test methods, and suggestions were made to improve these tests. The friction sensitivity for all submicron-sized crystals showed no ignition even at the highest possible load. The ballistic impact chamber tests showed also no or only partial ignition with all the submicron-sized explosives. The submicron-sized crystals were distributed among the grooves of the porcelain plate used in the friction test or among the sand grains of the sandpaper used in the ballistic impact chamber test. There is a need to revisit the ignition mechanism of these sensitivity test methods, and make suggestions for accurate measurement methods for the sensitivity of nano-sized explosives. Recommendations have been suggested to develop new tests that only rely on the interactions between the particles making them applicable to conduct the sensitivity tests for submicron/nano-sized energetic materials. A friction initiation setup as developed at TNO more than 30 years ago, might be a technique that could provide a more reliable measurement of the friction sensitivity of submicron- or nano-sized energetic materials by allowing only the frictional heating between the sample particles and exclude any other sources of frictional heating, allowing more reliable results.Process and EnergyMechanical, Maritime and Materials Engineerin
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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