1,721,006 research outputs found
Synthesis of Energy Intensive Industrial Processes: Methodological Aspects and a Case Study of a Sugarcane Conversion Plant
Full text linkThe topic of the present work is the synthesis of energy intensive industrial processes. The aims are to discuss methodologies already reported in the literature and to propose a new organized procedure for the generation and modification of system alternatives. The synthesis problem consists in the definition of the type and number of system components, their material connections and their operating parameters. The synthesis procedure proposed here starts with the definition of a Basic Plant Configuration which is the schematic representation of an original idea of the plant comprising all the components responsible for the chemical and mechanical transformations of the raw materials. Accordingly, the Heat Exchanger Network responsible for the heat transfer between system cold and hot streams is not comprised in the Basic Plant Configuration and the heat transfer feasibility is verified by using Pinch Analysis rules. This is also the approach of many studies published in the literature in the field of process integration, some of which are presented in Chapter 2. In the same chapter the synthesis of CHP systems is also addressed. This subproblem of the total site synthesis problem may be solved following different systematic procedures proposed in the literature. CHP systems are in fact a cost-effective way to locally satisfy the demand of productive processes for external heat and electricity provided that they are optimally sized. This can be done by applying computer-aided optimization procedures. A particular attention is given in this work to the formulation of the synthesis of steam networks, as a mixed-integer linear programming optimization of steam network superstructures. This and other methods proposed in the literature for the synthesis of energy systems are compared highlighting potentials, weaknesses and possible common criteria. The synthesis of a sugarcane conversion plant is studied in Chapters 3 and 4. In particular, in Chapter 3, the organized procedure for the generation and modification of process alternatives is applied and the process configurations for production of sugar and ethanol, also in combined mode, are discussed. Each plant configuration is optimized in order to minimize the process thermal demand. Main structural and operating parameters subject to optimization are those of the multi-effect evaporator and of the ethanol distillation subsystems. In Chapter 4 the synthesis of a bagasse fueled CHP system is studied and the potential for net electricity production to be sold to the market evaluated considering two options for the conversion of bagasse: combustion and gasification. The process for the combined production of sugar and ethanol and the CHP system are optimized simultaneously. In particular a two level optimization procedure is applied in this case. According to this procedure the structure and mass flow rates of the steam network are optimized in an inner step where the heat transfer feasibility is set as a constraint according to the Pinch Analysis rules. In an outer optimization step instead all the intensive parameters are optimized by means of a genetic algorithm based optimizer.L'argomento del presente lavoro è la sintesi degli impianti industriali ad alta intensità energetica. Gli obiettivi sono quello di discutere le metodologie già documentate in letteratura e di proporre una nuova procedura organizzata per la generazione e la modifica delle alternative di sistema. Il problema di sintesi consiste nella definizione del tipo e del numero di componenti di un sistema, le loro connessioni materiali e i loro parametri di funzionamento. La procedura di sintesi qui proposta inizia con la definizione di una Basic Plant Configuration la quale consiste nella rappresentazione schematica di un'idea originale del sistema, comprendente tutte i componenti responsabili delle trasformazioni chimiche e meccaniche delle materie prime. La rete degli scambiatori di calore responsabile per il trasferimento di calore tra i flussi freddi e caldi del sistema non risulta pertanto compresa nella Basic Plant Configuration e la fattibilità fisica dello scambio termico è verificata applicando le regole della Pinch Analysis. Questo è anche l'approccio di molti studi pubblicati in letteratura in materia di process integration, alcuni dei quali sono presentati nel Capitolo 2. Nello stesso capitolo si affronta il problema della sintesi dei sistemi di cogenerazione. Questo sottoproblema del problema di sintesi del sito industriale totale può essere risolto seguendo diverse procedure sistematiche proposte in letteratura. I sistemi di cogenerazione sono in realtà un modo economicamente efficace per soddisfare localmente la domanda dei processi produttivi di calore e di elettricità a condizione che siano ottimamente dimensionati. Ciò può essere fatto applicando delle procedure di ottimizzazione che fanno uso di calcolatore. Una particolare attenzione viene data in questo lavoro alla formulazione della sintesi delle reti di vapore come un problema di programmazione mista intera lineare di su una sovrastruttura di rete di vapore. Questo e altri metodi proposti in letteratura per la sintesi di sistemi energetici vengono confrontati evidenziando potenzialità, debolezze e possibili criteri comuni. La sintesi di un impianto di trasformazione della canna da zucchero è studiato nei Capitoli 3 e 4. In particolare, nel Capitolo 3, si applica la procedura organizzata per la generazione e la modifica di alternative processo e si discutono le configurazioni di processo per la produzione di zucchero ed etanolo anche in modalità combinata. Ogni configurazione dell'impianto è ottimizzata al fine di ridurre al minimo la richiesta termica del processo. I principali parametri strutturali e di design soggetti all'ottimizzazione sono quelli del evaporatore multi effetto e del sottoprocesso di distillazione dell'etanolo. Nel capitolo 4 si studia la sintesi di un sistema di cogenerazione alimentato con il sottoprodotto bagassa e si valuta il potenziale di produzione di energia elettrica netta da vendere ad un eventuale mercato elettrico considerando due opzioni per la conversione della bagassa: combustione e gassificazione. Il processo per la produzione combinata di zucchero e di etanolo e il sistema di cogenerazione sono ottimizzati simultaneamente. In particolare una procedura di ottimizzazione a due livelli viene applicata in questo caso. Secondo questa procedura la struttura e la portate di massa della rete di vapore sono ottimizzate in un'iterazione interna, dove la fattibilità fisica dello scambio termico è fissata come vincolo secondo le regole della Pinch Analysis. In un'iterazione esterna di ottimizzazione invece tutti i parametri intensivi sono ottimizzati per mezzo di un ottimizzatore basato su un algoritmo genetico
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
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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