1,720,965 research outputs found
Valorization of Pyrolysis Products Derived from Waste
No full textThe demand for sustainable energy and circular resource management is driving research into bio-based and waste-derived materials. In this context, pyrolysis is emerging as an efficient and versatile technology, converting waste into oil, gas, and char fractions that can serve as raw materials for fuels, chemicals, and smart materials. This thesis focuses on valorizing pyrolysis-derived fractions from both lignocellulosic and non-lignocellulosic biomass, as well as plastic waste. Specifically, the first part of the research explores biochar, a solid fraction obtained by slow pyrolysis of biomass sources like hazelnut shells, rice husks, rice grains, and tannery leather shavings. These biochars were transformed into activated carbons to support Pd- and Co-based catalysts. Pd-supported catalysts were applied in benzaldehyde hydrogenation as model reaction to investigate the influence of biochar feedstock on catalytic performance. Activated rice husk biochar (A-RH) emerged as the optimal support. Additionally, co-pyrolyzing rice husk with leather shavings produced a new hybrid material with enhanced catalytic properties and selectivity. Leveraging these insights, Co-based catalysts were synthesized and applied in the hydrodeoxygenation (HDO) of isoeugenol and furfural. These compounds represent the phenolic and furanic fractions of bio-oil, that could be used as alternative source of fuels, especially in the aviation sector. Co/A-RH demonstrated superior activity, attributed to its intrinsic properties and strong interaction with the metal phase, facilitating synergy between Co0 and Co2+ species. Lastly, part of this research targeted plastic-derived chars, successfully converting them into carbon monoxide via the Boudouard reaction, improving the carbon balance in chemical recycling of plastics and contributing to carbon capture and reutilization. Overall, this thesis highlights the transformative potential of waste-derived materials in catalysis, supporting sustainable fuel production and offering viable strategies for enhanced circular resource utilization.The demand for sustainable energy and circular resource management is driving research into bio-based and waste-derived materials. In this context, pyrolysis is emerging as an efficient and versatile technology, converting waste into oil, gas, and char fractions that can serve as raw materials for fuels, chemicals, and smart materials. This thesis focuses on valorizing pyrolysis-derived fractions from both lignocellulosic and non-lignocellulosic biomass, as well as plastic waste. Specifically, the first part of the research explores biochar, a solid fraction obtained by slow pyrolysis of biomass sources like hazelnut shells, rice husks, rice grains, and tannery leather shavings. These biochars were transformed into activated carbons to support Pd- and Co-based catalysts. Pd-supported catalysts were applied in benzaldehyde hydrogenation as model reaction to investigate the influence of biochar feedstock on catalytic performance. Activated rice husk biochar (A-RH) emerged as the optimal support. Additionally, co-pyrolyzing rice husk with leather shavings produced a new hybrid material with enhanced catalytic properties and selectivity. Leveraging these insights, Co-based catalysts were synthesized and applied in the hydrodeoxygenation (HDO) of isoeugenol and furfural. These compounds represent the phenolic and furanic fractions of bio-oil, that could be used as alternative source of fuels, especially in the aviation sector. Co/A-RH demonstrated superior activity, attributed to its intrinsic properties and strong interaction with the metal phase, facilitating synergy between Co0 and Co2+ species. Lastly, part of this research targeted plastic-derived chars, successfully converting them into carbon monoxide via the Boudouard reaction, improving the carbon balance in chemical recycling of plastics and contributing to carbon capture and reutilization. Overall, this thesis highlights the transformative potential of waste-derived materials in catalysis, supporting sustainable fuel production and offering viable strategies for enhanced circular resource utilization
PROCESS FOR TREATING CHAR FROM RECYCLED PLASTICS
No full textA process for recovering the carbon contained in a char (solid carbonaceous residue) from a pyrolysis of mixed plastic waste or secondary raw material obtained from the recycling and/or treatment of plastic wastes is described, said process comprising the following steps: (A) heating said char in a gasification reactor and in the presence of carbon dioxide to reach a given temperature comprised in a range lower than 950°C and higher than 600°C, preferably lower than or equal to 850°C; (B) continue heating said char in the aforementioned temperature range, preferably in the range from 750 °C to 850 °C, in the presence of CO2, for a given residence time of said char in said reactor producing an outflow gas stream (effluent) comprising CO in addition to unreacted CO2, and possibly H2, (C) sending at least a part of the gas stream (effluent) leaving the reactor comprising CO, unreacted CO2, and optionally H2, to at least one subsequent operating unit selected from a unit for separating CO from CO2, a direct use unit of said outflow stream or to a storage unit
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
On the Applications as Catalytic Support of Biochars Obtained by Pyrolysis of Waste Biomasses
No full textBiochars, as carbon rich materials with tuneable properties and a chemical composition of various doping and functionalized elements, are a promising option for many different applications. In this work, biochars were obtained by pyrolysis of different biomasses from vegetal (hazelnut shells, vine wood waste, barley waste, rice husks, and Sargassum, macroalgae of Venetian lagoon) and animal (leather tannery waste) origins. The activation was performed either by CO2 or steam physical treatment at high temperature. Biochars and activated biochars were characterized by elemental analysis, N2 physisorption, and FTIR techniques. The chemical, morphological, and textural properties of the biochars were strongly affected not only by the origin of the starting biomass, but also by pyrolysis conditions and activation parameters. Some examples of applications of these activated biochars as support for different metal catalysts in biomass valorisation reactions will be presented. In particular, the following samples were investigated: i) Ru/C catalysts for the hydrogenation of 5-hydroxymethylfurfural. ii) Pd/C catalysts for benzaldehyde hydrogenation to toluene. iii) Ni/C catalysts for the conversion of levulinic acid to γ-valerolactone. The catalytic performances were discussed comparing the prepared samples with commercial references. It can be postulated that biomass wastes properly treated with pyrolysis can not only be recycled but also upgraded
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
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