1,720,952 research outputs found
Isolation and characterization of lignins from Wheat straw and cardoon biomasses
Get PDF2020 - 2021The progressive reduction in the availability of oil resources, the unstoppable increase in their costs
and the growing need for efficient environmental protection, imply an urgent development of new
technologies for the exploitation of renewable energy with low environmental impact. From this
point of view, lignocellulosic materials represent one of the largest reservoirs of solar energy stored
in the chemical bonds of the most abundant forest biopolymers on Earth: cellulose and lignin. These
resources are continuously renewed and have great potential for obtaining combustible substances
and for the preparation of raw materials and intermediate molecules for the fine chemistry for
industrial applications. From an environmental point of view there would be a considerable
advantage to use a renewable source of raw material such as biomass, avoiding the use of fossil
fuels and helping to decrease the concentration of greenhouse gases in the atmosphere. The design
and development of new plant biomass materials and processes requires the identification and
development of new analytical techniques for the structural characterization of biopolymers and the
monitoring of the extent of biopolymer degradation of lignocellulosic materials. The research
project is aimed at the use of waste lignocellulosic raw materials not competing with the food
supply chain to produce products or materials to be re-inserted into the production cycle as a
replacement (partial) of the current products of origin fossil. All this is consistent with the industry
4.0 model, which envisages rebuilding a constructive and balanced relationship between industry
and all other components of the economy through the development of a circular economy.
Economic and environmentally efficient pathways for production and utilization of lignocellulose
for chemical products and energy are needed to expand the bioeconomy.
The use of residual biomasses to obtain bioenergy and green chemicals is a real possibility to
contribute to sustainable development. These materials are composed mainly of polycarbohydrates
(cellulose, hemicellulose) and phenolic polymers (lignin) and have great potential for use.
One of the most interesting topics of the so-called "green chemistry" is the valorisation of lignin, a
natural substance that can be isolated from biomass. Lignin is one of the three main components of
plant cells along with cellulose and hemicelluloses (Fig.1). The development of the cellulose and
hemicellulose transformation chain in biorefinery ambitions has already achieved industrial
objectives, while the study of lignin for these applications is still in a pioneering phase of
experiments that hopefully will help resolve some negative aspects related to the use of fossil-based
products. The particular chemical composition of lignin is potentially suitable to replace fossil
sources in the production of basic chemicals and some polymers.
For many years, this macromolecule has been used almost exclusively, after isolation, for energy
purposes in the pulp and paper industries. Today, lignin is considered a potential renewable
precursor in the development of high-value applications such as controlled release devices, novel
composites, nanoparticle applications, application devices in electronics, carbon fiber
manufacturing, and absorbing and dispersing agents. Furthermore, among the various applications,
lignin is currently being studied to be used in the future as a starting point for the preparation of
adhesives for the production of green building panels, polyurethanes and coating surfaces. The aim
of the thesis project was to isolate the lignins derived from wheat straw and cardoon residues by
different extraction techniques and to characterize them to highlight the structural properties and
therefore the potential applications. [edited by Author]XXXIV cicl
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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