1,721,038 research outputs found
Is pyrolysis bio-oil prone to microbial conversion into added-value products?
Full text linkIn view of the potential application of pyrolysis-based biotechnologies, it is crucial to look for novel microorganisms able to convert pyrolysis-derived products, in particular bio-oil water-soluble constituent, into valuable compounds. For the first time, this paper proposed a survey on a collection of bacterial, yeast, and fungal strains with well-known industrial properties as well as new bacterial isolates in order to select microbes able to both tolerate bio-oil inhibitors and convert bio-oil into valuable products. This survey found that bio-oil aqueous phase (BOAP) obtained from intermediate pyrolysis could be metabolized as it is by fungal strains whereas several dilutions are needed to do not hamper cell viability of many tested yeast and bacterial isolates. To process BOAP into valuable products, the yeast Saccharomyces cerevisiae L13, selected as the most industrially relevant tested strain, was adopted to convert bio-oil aqueous fraction hydrolysate into ethanol without any detoxification step. The fermenting performances were much greater than those of the benchmark yeast strain and S. cerevisiae L13 proved to be a strong candidate for bioethanol production from BOAP hydrolysates. This study demonstrated that the search for microorganisms is a promising approach to the future development of pyrolysis oil-based biorefinery platforms
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
Analytical pyrolysis of poly(dimethylsiloxane) and poly(oxyethylene) siloxane copolymers. Application to the analysis of sewage sludges
Full text linkDimethicone (poly(dimethylsiloxane), PDMS) and its copolymers bearing a poly(ethylene glycol) (PEG) side chain (PEG-12 dimethicone and PEG-8 dimethicone) are utilised as ingredients in personal care products. These materials along with bis-PEG-18 methyl ether dimethyl silane were analysed by Py-GC–MS. The pyrolysates of dimethicone was dominated by cyclic dimethyl siloxanes from D3 to over D10. Besides Dn, the pyrolysates of PEG-dimethicone were featured by the presence of linear dimethyl siloxanes Ln. Hydroxylated siloxanes were also tentatively identified. Pyrograms were also characterised by PEG oligomers with different terminal groups (hydroxyl, ethyl, ethenyl). The molecular structure of pyrolysis products from the combined structural units of PDMS and PEG could not be assigned. Internal standard calibration protocols using pyrolysis products of PEG-12 dimethicone (L6, L8, L9, and triethyleneglycol monoethyl ether) exhibited satisfactory linearity (R2 > 0.992) in the 0.75−58 μg range and repeatability (RSD < 15 %). Three samples of dried sewage sludge from a municipal water treatment plant were extracted with tetrahydrofuran and the extracts analysed by Py-GC–MS. The pyrograms were characterised by intense signals due to the lipid matrix (hydrocarbons, fatty acids, steranes, sterenes, sterols). Dn and Ln were identified indicative for the presence of siloxanes at levels around 60−290 μg gdw−1, while pyrolytic markers of PEG were not revealed. The recovery of PEG-12 dimethicone (17 μg) in spiked sample was 76 %. Galaxolide, galaxolide lactone and triclosan were identified in the pyrograms. The results of this study evidenced the potential of Py-GC–MS as a screening tool for the determination of cosmetic ingredients in sewage sludge
An original Arduino-controlled anaerobic bioreactor packed with biochar as a porous filter media
Full text linkBioreactors are commonly used apparatuses generally equipped with several built-in specifications for the investigation of biological treatment studies. Each bioreactor test may require different types of specialty such as heating, agitation, re-circulation and some further technologies like online sensoring. Even thought, there are many ready-to-use fabricated bioreactors available in the market with a cost usually over than 1000 €, it is often not possible to access those advanced (but inflexible) systems for many students, young-researchers or small-scale private R&D companies. In this work, a new low cost (≈100€) packed-bed anaerobic bioreactor was developed, and all methodological details including open-source coding and 3D design files are shared with informative descriptions. Some preliminary tests were conducted to verify the developed bioreactor system's credibility in terms of leak-tightness, accurate gas monitoring, temperature controlling, and mass balance (COD-eq) coverage, which all have shown a very promising performance. • A consistent model bioreactor that will be called as “tetrapod” was developed for anaerobic treatment of challenging substrates such as pyrolytic liquids. • Coarse biochar grains were used as an organic packing material to stimulate the microbial bioconversion by increasing the active surface area for the attached-growth anaerobic mixed microbial culture (MMC). • An open-source Arduino based digital gasometer was developed for online monitoring of biogas change in the lab-scale system. Arduino was also used as a digital controller for maintaining pulse-mode liquid recirculation of the bioreactor
Analytical evaluation of the performance of pyrolysis-gasification (Py-Gs) combination within hybrid thermochemical-biological biorefinery
Full text linkThermochemical treatments like pyrolysis and gasification, were proposed to circumvent hydrolysis bottleneck of conventional 2nd generation biorefineries. Within this big-picture, the target of this article was to establish the type and amount of bioavailable matter that can be obtained through intermediate pyrolysis of biomass followed by gasification of biochar. To establish the amount of "chemical energy " partitioned among different products ' chemical oxygen demand (COD), which is proportional to higher heating value (HHV) and often utilized for biological systems, was applied for the evaluation of thermochemical conversion of a lignocellulosic feedstock (fir wood). The most abundant product of intermediate pyrolysis was biochar, which retains from 33 % to 40 % of feedstock COD (with temperatures starting from 450 degrees C). The yield of water-soluble pyrolysis products (WS) slightly increases from 24 % at 450 degrees C to 27 % at 650 degrees C, whereas the yield of WI increases considerably with the same temperature. Pyrolysis temperature showed a minor effect on the composition of WS as revealed by GC-MS analysis of main compounds and size exclusion chromatography. Preliminary gasification experiments, performed at 850 degrees C under CO 2 atmosphere, provided gasification rates for different biochars, which was equal to 0.004, 0.005, 0.006 min -1 for biochars obtained at 650, 550, and 450 degrees C respectively. Syngas obtained from gasification of 450 degrees C and 550 degrees C biochar was almost tar-free, whereas gasification of 650 degrees C biochar yielded a detectable amount of tars (0.4 %). Increasing the gasification temperature to 950 degrees C sharply increases the gasification rate of biochar obtained at 450 degrees C, allowing to obtain 55% conversion yield. Within the scope of hybrid thermochemical-biological (HTB) processes, the obtained results show that intermediate pyrolysis, when coupled with subsequent 950 degrees C CO 2 gasification of biochar, can deliver 64% of chemical energy (by COD basis) of the lignocellulosic feedstock as bioavailable constituents, which are defined to syngas and WS based on recent biological studies. Whereas downstream fermentation can process syngas and WS materials in an effective way, such yields could surpass the holocellulose-targeted methods based on hydrolysis
CROSS-LIFE: poly(vinyl acetate-co-crotonic acid) from bio-based synthesis - preliminary LCA results
No full textRecovery of Polyhydroxyalkanoates From Single and Mixed Microbial Cultures: A Review
Full text linkAn overview of the main polyhydroxyalkanoates (PHA) recovery methods is here reported, by considering the kind of PHA-producing bacteria (single bacterial strains or mixed microbial cultures) and the chemico-physical characteristics of the extracted polymer (molecular weight and polydispersity index). Several recovery approaches are presented and categorized in two main strategies: PHA recovery with solvents (halogenated solvents, alkanes, alcohols, esters, carbonates and ketones) and PHA recovery by cellular lysis (with oxidants, acid and alkaline compounds, surfactants and enzymes). Comparative evaluations based on the recovery, purity and molecular weight of the recovered polymers as well as on the potential sustainability of the different approaches are here presented
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