1,721,140 research outputs found
Biohydrogen production from buffalo manure codigested with agroindustrial by-products in an anaerobic reactor
No full textMost on-farm biogas plants in Europe use animal waste and co-substrates for biogas production (CH4 and CO2 mixture). However combined hydrogen and methane production in a twostage process is a concept which has been developed in recent years and it is more promising from an energy perspective. The aim of this research was to explore hydrogen production from buffalo manure alone and in co-digestion with suitable feedstocks (low protein cheese whey and crude glycerol from biodiesel manufacturing). Experiments were carried out in batch reactor at 37 °C using a microbial consortia as inoculum. In a first set of batch trials the sterilization effect on hydrogen production from each individual substrate was explored. Results showed that sterilization increased hydrogen production yield (mL H2/g VS) in all substrates, even reaching a three times higher yield in the case of buffalo manure. In a second set of experiments hydrogen production using different mixing ratios of sterilized substrates were investigated. Results showed that the hydrogen production yield from manure codigested with 10% glycerol or 10% of low protein cheese whey (LPCW), was increased from 37.7 mL H2/g VS to 47.2 and 65.4, respectively. Moreover the co-digestion decreased H2 production time from 114 hrs to 24 hrs. The yields further increased up to 116 mL H2/g VS when a combination of 70% manure, 20% LPCW and 10% glycerol was used. During the experiments CH4 was not detected. Buffalo manure, when codigested with LPCW and glycerol gave interesting yield together with an optimum buffering capacity avoiding the use of any external buffer/pH control system
Natura ed arte: le iris nella pittura
No full textSono state esaminate circa 50 opere di pittori che hanno dipinto con tecniche diverse varie specie di iris di cui è stata effettuata l'identificazione opera per oper
Self-fermentation: Innovative pretreatment for use high concentration of olive mill wastewater in anaerobic digestion plant
No full textThis study aimed to evaluate the impact of self fermentation on methane production as biological pretreatment of olive mill wastewater (OMW). The self-fermentation was carried out at room temperature without mixing and at natural light cycle. The batch assays were performed at the influent substrate concentration of 36.7 g VS/l (OMW 100%), 18,4 g VS/l (OMW 50%) and 9.2 g VS/l (OMW 25%). The methane production was performed at 37°C in mixing condition. The results of methane production were compared with those obtained using untreated OMW. The results of this study showed that the self fermentation process is a very effective pretreatment to produce methane. Only the self-fermented samples have produced methane from undiluted OMW and a maximum cumulative methane production of 7583 ± 138 mlCH4/L and a yield of 246 ± 10 mlCH4/ gVS were obtained. A yield increase of +13.5% at OMW dilution of 50% was also achieved as compared to untreated OMW results. Interestingly, in the anaerobic digestion of untreated OMW, high hydrogen yields, with an average value of 46.8 ± 1.9 mlH2/gVS, were obtained. Moreover a depletion around 20% v/v of polyphenols was recorded for all experimental set. © 2016 ETA-Florence Renewable Energies
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
From polluting seafood wastes to energy. production of hydrogen and methane from raw chitin material by a two-phase process
No full textHydrogen is a clean energy carrier having great potential as alternative fuel. Despite its well-established production, by chemical/electrochemical processes, bio-conversion of organic wastes to hydrogen could be a sustainable alternative since the afore-mentioned methods require a lot of energy. Anaerobic digestion to bio-methane is considered a winning strategy to transform wastes into energy with reduction of environmental issues. Chitin is the second most abundant polysaccharide after cellulose. Huge amounts of chitinous wastes, produced from seafood industry and fungal fermentation plants, represent source of pollution if improperly disposed. In this paper the feasibility to obtain hydrogen and methane in a two-phase anaerobic bio-process using raw chitin was investigated. After a preliminary aerobic pre-hydrolysis, carried out by the chitinolytic fungus Lecanicillium muscarium CCFEE 5003, H2, was obtained by dark fermentation and CH4, subsequently, by further digestion. For best productions, pre-hydrolysis was optimised by response surface methodology. Highest hydrogen (147 ml/1) and methane (7713 ml/1) levels were obtained after 24 days of dark fermentation and 83 days of digestion, respectively. However, best productivities were obtained at day 14 and 30 for H2, and CH4, respectively. This work is the first attempt to use raw chitin to obtain these biofuels by dark fermentation and anaerobic digestion
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
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