1,720,961 research outputs found
Life cycle assessment of hydrogen production from biorefinery residues
No full textGasification of biomass can be used for obtaining hydrogen so reducing the greenhouse gases emissions due the fixation of CO2 during photosynthetic processes. The hydrolytic lignin residue is an appropriate raw material since it does not compete directly with the food chain and can be exploited for producing additional chemicals, power, combined heat and power. Indeed, the optimal use of this residue is a key factor for the economic and environmental sustainability of a bio-refinery, not only disposal costs can be avoided but also additional incomes can be provided. The work dealt the environmental potentials impacts of the production of hydrogen through gasification of this residue and to identify the hotspots of the process. An LCA study was developed for a 200 kWth gasification pilot plant using experimental data. Model was constructed using GaBi software in accordance with LCA leading Standards and ILCD Handbook recommendations. A gate-to-gate analysis of the gasification process was carried out and compared to a reference scenario consisting of hydrogen production by steam reforming of methane. LCA methodology was applied using global warming potential, acidification, eutrophication and the gross energy necessary for the production of 1 kg of hydrogen as impact categories
Produzione di zuccheri da biomassa residuale in una bioraffineria alimentata da cardo. Bilanci da massa e di energia e valutazione delle impronte ambientali
Full text linkQuesto rapporto illustra le diverse fasi di sviluppo della filiera agroindustriale innovativa e sostenibile del cardo, dal recupero delle materie agricole di scarto su terreni marginali o incolti alla produzione di intermedi chimici e prodotti bio-based con specifiche applicazioni nel settore delle bioplastiche. Il suo focus principale è la definizione, e successiva ottimizzazione, dello schema di processo che porta alla produzione di zuccheri di II generazione (Z2G) in una bioraffineria alimentata da biomassa residuale di cardo seguita dal calcolo dell’impatto ambientale dell’intero processo. L’importanza industriale strategica
degli Z2G risiede nella possibilità di essere trasformati, per via fermentativa, in bio-Butandiolo (bio-BDO) da impiegare nella produzione di alcune tipologie di bioplastiche.
In primis, è stato sviluppato lo schema di filiera, suddiviso in tre fasi principali: la coltivazione del cardo, il trasporto della biomassa all’impianto di bioraffineria e la trasformazione del residuo lignocellulosico in Z2G. Successivamente, per ciascuna fase è stato individuato l’insieme delle operazioni elementari necessarie alla loro corretta esecuzione e sono stati definiti i flussi di materiali ed energia in ingresso ed in uscita. In particolare, per la fase di bioraffineria, è stato definito il layout di processo ed eseguito
il corretto dimensionamento degli impianti considerando una capacità teorica pari a 60 kton/anno, compatibile con le potenzialità stimate dei bacini di approvvigionamento locali. Infine, sono stati costruiti i bilanci di materia ed energia e, sull’intera filiera è stata condotta un’analisi semplificata dell’impatto ambientale attraverso la valutazione dell’impronta di carbonio (carbon footprint) e dell’impronta idrica (water footprint) utilizzando un approccio di tipo LCA (Life Cycle Assessment). I risultati ottenuti, seppur affetti da alcune limitazioni concettuali legate ad alcune assunzioni per alcuni stadi di trasformazione, hanno evidenziato che, per quanto riguarda i processi di bioraffineria, la produzione di Z2G si autosostiene dal punto di vista dell’energia termica mentre circa il 93% della domanda
totale di energia elettrica può essere soddisfatta dall’unità di cogenerazione. Il contributo
complessivo alle emissioni di gas serra dato dalla produzione di Z2G da cardo è pari a 0,79 kgCO2eq per kg di zuccheri prodotti (kgZ2G). La fase di coltivazione impatta per un valore pari a 0,69 kgCO2eq/kgZ2G. La fase di trasporto, ipotizzando una distanza teorica tra il campo e l’impianto pari a 100 km A/R (ipotesi di filiera corta), contribuisce per un valore pari a 0,025 kgCO2eq/kgZ2G. Da ultima, la fase di bioraffineria incide complessivamente per un valore pari a 0,076 kgCO2eq/kgZ2G.This report illustrates the different stages of development of the innovative and sustainable agro-industrial chain of the thistle, from the collection of agricultural waste materials on marginal or uncultivated lands to the production of chemical intermediates and bio-based products with specific applications in the bioplastics sector. Its main focus is the definition, and subsequent optimization, of the process scheme that leads to the production of II generation sugars (2GS) in a biorefinery fed by residual thistle biomass followed by the calculation of the environmental impact of the entire process. The strategic industrial importance of 2GSs lies in the possibility of being transformed, by fermentation, into bio-Butandiol (bio-BDO) to be used in the production of some types of bioplastics. First, the supply chain scheme was developed, divided into three main phases: the cultivation of the
thistle, the transport of biomass to the biorefinery plant and the transformation of the lignocellulosic residue into 2GS. Subsequently, for each phase, the set of elementary operations necessary for their correct execution was identified and the flows of materials and energy in input and output were defined. In particular, for the biorefinery phase, the process layout was defined and the correct sizing of the plants was carried out considering a theoretical capacity of 60 ktons/year, compatible with the estimated potential of the local supply basins. Finally, mass and energy balances were built and, on the entire supply chain, a simplified environmental impact analysis was carried out by assessing the carbon
footprint and the water footprint using an LCA (Life Cycle Assessment) approach. The obtained results, although affected by some conceptual limitations linked to some assumptions for some stages of transformation, have shown that the biorefinery production process of 2GS is selfsustaining concerning the thermal energy and that about 93% of the total electricity demand can be satisfied by the cogeneration unit of the plant. The overall contribution to greenhouse gas emissions from the production of 2GS is equal to 0.79 kgCO2eq per kg of sugars produced (kg2GS). The cultivation phase impacts for a value of 0.69 kgCO2eq/kg2GS. The transport phase, assuming a theoretical distance between the field and the plant equal to 100 km A/R (short chain hypothesis), contributes a value equal to 0.025 kgCO2eq/kg2GS. Lastly, the biorefinery phase accounts for a total of 0.076 kgCO2eq/kg2GS
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
Bioproducts Extraction from Agro-Industrial By-Products and Their Valorisation. Development of Process Layouts
No full textThe agro-food industry generates important quantities of by-products, often considered waste, which represent for the companies huge costs of handling and disposal. On the other hand, they contain copious amounts and varieties of compounds that, appropriately extracted, purified, and processed, can be valued in several industrial sectors. Their exploitation generates an improvement of the sustainability performance of the supply chains, since it generates economic advantages, making available new commercial products and reducing disposal costs, improves the environmental performance of the agro-industrial productions, and allows new employment opportunities, thanks to the development of new industrial sectors. The Percival project aims to valorize the byproducts of agro-industrial supply chains of South of Italy, converting them into high-added value products, through innovative, efficient, and low environmental impact processes, going for the development of technologies that could represent new business opportunities for this territory. Particularly, the project deals with the development of processes for pretreatment, extraction, separation, and chemical/biotechnological transformation, using a biorefinery cascade approach. Indeed, the study of processes having the purpose of converting the residues from the above-mentioned transformations into advanced biofuels (biomethane) and agricultural products (e.g. soil improver and bio-stimulants) are also included in the project’s scope. The present paper provides an overview of the Percival project, along with the evaluation of the availability of residual biomasses from the supply chains of typical Southern agricultural products, and the valuable bioproducts achievable from these feedstocks, through a biorefinery processing scheme
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
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