1,721,061 research outputs found
Design and first tests of a micro lab scale (2kg/h) gasifier
No full textMost of the gasification systems cost various tens or hundreds of thousands of euros, take up a lot of space and need trained staff to be operated. This implies that biomass gasification tests are usually expensive and complex to carry out. From all these difficulties arise the need of a solution that is simple, cheap and small, allowing experimental studies without all the issues related to a commercial power plant. A laboratory scale gasifier was designed and built to meet this need. The main features of the system are the use of stainless steel for all the parts, the small size that allows to use it on a worktable and the nominal biomass flow rate of 2 kg/h. Data from literature was used to size the gasifier and choose its main parameters after an interpolation process. The interpolation was necessary because most of the data available refers to systems at least one order of magnitude more powerful than this prototype. Fir wood pellet was tested as a benchmark of the gasification system. Thanks to the manageability of the system it will allow to test different kinds of biomass. Gas-chromatographic analyses and tar and particulate sampling were carried out in order to evaluate the gas produced by the system. Elemental analysis of the char extracted from the lower part of the gasifier was performed to assess its quality. First results showed that the composition and the amount of contaminant of the gas are similar to the ones produced in much bigger power plant and also the char composition is the typical one for pyrogasification
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
Energy cost and parmesan cheese. An overview in the different energy fluxes needed to produce a parmesan wheel
Full text linkAgriculture is responsible for up to 30% of the greenhouse gases emission, and cattle breeding is the main contributor making up almost 10% of the total. For this reason, this sector is a key player toward a complete decarbonization. To take the proper action to reduce climate impact of cattle breeding, it is necessary to know the energy requirements of the industry. This work focuses on the energy mapping of a parmesan cheese production, with reference to an agricultural company situated in Modena province with about six hundred animals. Knowing the electrical and thermal energy requirements to produce a wheel of cheese gives the possibility to the farmers to identify and reduce the energy wastage as well as starting the implementation of a strategy for fossil fuel substitution. In this study, a comprehensive monitoring campaign is presented together with the proposal of some possible improvements. The analysis showed that, considering the actual situation, about 64 kWh of electrical energy and 94 kWh of thermal energy are needed to produce a parmesan cheese wheel, while the fuel used to feed the agricultural machinery (e.g., tractors) accounts for around 174 kWh. In this context, the implementation of biogas and solar photovoltaic can greatly contribute to reduce the dependence on fossil fuels
Domestic heating: Can hemp-hurd derived pellet be an alternative?
Full text linkAmong the renewable sources, residual woody biomass from agricultural crops is becoming of great interest due to its lower environmental impact and one of the most growing agricultural sector, of the last decade, is the hemp industry which generates several kind of byproducts. In this paper, a blend of 50% of hemp-hurd and 50% of fir sawdust was pulverized and pelletized. The pellets were burned into a domestic pellet stove (9 kWth maximum nominal thermal power output) at different biomass flowrates. To compare results with a commercial-grade pellet, the tests were repeated by fueling the same stove with A2-grade pellets. Results shown that the pellet mixture 50/50 of fir sawdust and hemp-hurd is suitable for the commercial pellet stove used and that the slightly higher amount of ashes (2.7%), compared to pellet A2 (<1.2%), can be handled by the self-cleaning fire chamber. Comparable results were also obtained in regards with the stove global efficiency which ranged from 90.8-92.3% for the hemp pellets and 91-94% for the A2. A significant difference was noted in the biomass flowrate where, during the tests with hemp-hurd pellets a lower value was obtained (-20%) compared to A2. This resulted into lower power input in the stove and lower performances at the same nominal power output
Vine prunings agro – energetic chain: Experimental and economical assessment of vine pellets use in gasification power plants
No full textVine prunings are a very abundant by product of the wine industry and their production can be estimated to be between 1 to 5 ton/year for every hectare. In the view of a decarbonisation and the development of the circular economy this biomass should become an opportunity even if in most of the cases it ends up being a problem. This is due to their common burning in situ that has a huge environmental impact, and to their shredding when left on the field that can be an infection source in presence of grape diseases. This work follows the one presented the 26th EUBCE “Gasification and wine industry: Report on the use vine pruning as fuel in small – scale gasifiers” where it was evaluated the possibility of producing electrical energy using this biomass as fuel in APL PP20 gasifier – engine system. The results of the previous work showed quite promising results about the gasification efficiency and the quality of the gas produced using this biomass, however the difficulties encountered during the reactor feeding and the bridging problems have made this process quite challenging. In order to overcome these issues, it was considered the possibility of pelletizing this biomass. More than 2.5 ton of pelletizing vine prunings were successfully gasified with a quite high efficiency, 1.1 kg consumed for every electric kWh produced. The 150 kg of biochar produced through the process were tested on a vineyard as soil improver. The entire supply chain, from the harvesting of the vine prunings on the field, to the pelletization and gasification, was economically evaluated considering different possible scenarios and some of them were quite profitable and therefore practically feasible
Corrigendum to “Seeking the synergistic potential of biochar integration in municipal composting plants for techno-economic and environmental leverage” [Sustain. Energy Tech. Assess., 64 (2024) 103717, 1–17] (Sustainable Energy Technologies and Assessments (2024) 64, (S2213138824001139), (10.1016/j.seta.2024.103717))
No full textDispelling 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
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