7,922 research outputs found
EU Agro Biogas Project
EU-AGRO-BIOGAS is a European Biogas initiative to improve the yield of agricultural biogas plants in Europe, to optimise biogas technology and processes and to improve the efficiency in all parts of the production chain from feedstock to biogas utilisation. Leading European research institutions and universities are cooperating with key industry partners in order to work towards a sustainable Europe. Fourteen partners from eight European countries are involved. EU-AGRO-BIOGAS aims at the development and optimisation of the entire value chain – to range from the production of raw materials, the production and refining of biogas to the utilisation of heat and electricity
Synthesis, Characterization and use of Nb2 O5 based Catalysts in Producing Biofuels by Transesterification, Esterification and Pyrolysis
Nb2O5/HX (X = HSO4-, H2PO4-, NO3-) compounds were obtained from the treatment of niobium acid (Nb2O5·xH2O) with sulfuric, phosphoric, and nitric acids as well as Nb2O5 and Nb2O5·xH2O have been investigated as catalysts for the transesterification, esterification and pyrolysis of vegetable oils. The compounds were characterized by thermal analysis (DTA-TGA), spectroscopy (DRX, FT-IR and FT-Raman), surface area (BET) and the acidity (Ho) determined by n-butylamine titration using the Hammet´s indicator method. It was observed that after the acid treatment both the surface area and the acidity decreased as compared to the starting Nb2O5·xH2O. The only exception was a higher acidity verified when nitric acid was used. Among the catalyst investigated, the Nb2O5/H3PO4 presented the highest activity in the alcoholysis of soybean oil with different mono-alcohols (methanol, ethanol, 2-propanol, n-butanol). All tested solids seemed to stabilize the carboxylic acids formed during the pyrolysis, yielding higher acid numbers for the obtained products. Finally, the use of Nb2O5/H3PO4 and Nb2O5/H2SO4 as catalysts for the esterification showed better activity than Nb2O5·xH2O and Nb2O5
Violation of Bell inequalities by photons more than 10 km apart
A Franson-type test of Bell inequalities by photons 10.9 km apart is
presented. Energy-time entangled photon-pairs are measured using two-channel
analyzers, leading to a violation of the inequalities by 16 standard deviations
without subtracting accidental coincidences. Subtracting them, a 2-photon
interference visibility of 95.5% is observed, demonstrating that distances up
to 10 km have no significant effect on entanglement. This sets quantum
cryptography with photon pairs as a practical competitor to the schemes based
on weak pulses.Comment: 4 pages, REVTeX, 2 postscript figures include
Pd(II)-dissolved in ionic liquids: a recyclable catalytic system for the selective biphasic hydrogenation of dienes to monoenes
Effect of Antimony and Cerium on the Formation of Chunky Graphite during Solidification of Heavy-Section Castings of Near-Eutectic Spheroidal Graphite Irons
Thermal analysis is applied to the study of the formation of chunky graphite (CHG) in heavysection castings of spheroidal graphite cast irons. To that aim, near-eutectic melts prepared in one single cast house were poured into molds containing up to four large cubic blocks 30 cm in size. Four melts have been prepared and cast that had a cerium content varying in relation with the spheroidizing alloy used. Postinoculation or addition of antimony was achieved by fixing appropriate amounts of materials in the gating system of each block. Cooling curves recorded in the center of the blocks show that solidification proceeds in three steps: a short primary deposition of graphite followed by an initial and then a bulk eutectic reaction. Formation of CHG could be unambiguously associated with increased recalescence during the bulk eutectic reaction. While antimony strongly decreases the amount of CHG, it appears that the ratio of the contents in antimony and cerium should be higher than 0.8 in order to avoid this graphite degeneracy
Selective hydrogenation of 1,3-butadiene by transition metal compounds immobilized in 1-butyl-3-methyl imidazolium room temperature ionic liquids
The compounds [Co(acac)2], [Co(acac)3], [Fe(acac)3] and [Ni(acac)2] (acac = acetylacetonate) dissolved in 1-butyl-3-methyl imidazolium tetrafluoroborate (1), trifluoromethanesulphonate (2) or hexafluorophosphate (3) catalyze the reduction of 1,3-butadiene into butenes in a typical two-phase catalytic reaction. The 1,3-butadiene conversion, the selectivity and turnover frequencies (TOF) are strongly dependent on the nature of the transition metal catalyst precursor and the ionic liquid. For [Co(acac)2] dissolved in 1, kinetic studies strongly suggest that the reaction takes place in the ionic solution bulk, having an apparent activation energy for the overall process of 33.8 kJ mol-1. The recovered ionic catalyst solution can be reused several times without any significant changes on activity and selectivity.Os complexos [Co(acac)2], [Co(acac)3], [Fe(acac)3] e [Ni(acac)2] (acac = acetilacetonato) dissolvidos em tetrafluoroborato de 1-butil-3-metilimidazônio (1), trifluorometanosulfonato de 1-butil-3-metilimidazólio (2) ou hexafluorofosfato de 1-butil-3-metilimidazólio (3), catalisam a hidrogenação de 1,3-butadieno em butenos em sistema catalítico tipicamente bifásico. A conversão do 1,3-butadieno, a seletividade e a freqüência de rotação (TOF) são fortemente dependentes do metal de transição e do líquido iônico. Para [Co(acac)2] dissolvido em 1, estudos cinéticos sugerem que a reação ocorre no meio líquido iônico, com uma energia aparente de ativação de of 33.8 kJ mol-1. A solução iônica do catalisador pode ser recuperada e reutilizada várias vezes sem mudanças perceptíveis na atividade e seletividade da reação
First light of the VLT planet finder SPHERE. I. Detection and characterization of the sub-stellar companion GJ 758 B
GJ758 B is a brown dwarf companion to a nearby (15.76 pc) solar-type,
metal-rich (M/H = +0.2 dex) main-sequence star (G9V) that was discovered with
Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being
the coldest (~600K) companion ever directly imaged around a neighboring star.
We present new high-contrast data obtained during the commissioning of the
SPHERE instrument at the VLT. The data was obtained in Y-, J-, H-, and Ks-bands
with the dual-band imaging (DBI) mode of IRDIS, providing a broad coverage of
the full near-infrared (near-IR) range at higher contrast and better spectral
sampling than previously reported. In this new set of high-quality data, we
report the re-detection of the companion, as well as the first detection of a
new candidate closer-in to the star. We use the new 8 photometric points for an
extended comparison of GJ758 B with empirical objects and 4 families of
atmospheric models. From comparison to empirical object, we estimate a T8
spectral type, but none of the comparison object can accurately represent the
observed near-IR fluxes of GJ758 B. From comparison to atmospheric models, we
attribute a Teff = 600K 100K, but we find that no atmospheric model can
adequately fit all the fluxes of GJ758 B. The photometry of the new candidate
companion is broadly consistent with L-type objects, but a second epoch with
improved photometry is necessary to clarify its status. The new astrometry of
GJ758 B shows a significant proper motion since the last epoch. We use this
result to improve the determination of the orbital characteristics using two
fitting approaches, Least-Square Monte Carlo and Markov Chain Monte Carlo.
Finally, we analyze the sensitivity of our data to additional closer-in
companions and reject the possibility of other massive brown dwarf companions
down to 4-5 AU. [abridged]Comment: 20 pages, 15 figures. Accepted for publication in A&
Long-distance Bell-type tests using energy-time entangled photons
Long-distance Bell-type experiments are presented. The different experimental
challenges and their solutions in order to maintain the strong quantum
correlations between energy-time entangled photons over more than 10 km are
reported and the results analyzed from the point of view of tests of
fundamental physics as well as from the more applied side of quantum
communication, specially quantum key distribution. Tests using more than one
analyzer on each side are also presented.Comment: 22 pages including 7 figures and 5 table
Imaging mass cytometry analysis of Becker muscular dystrophy muscle samples reveals different stages of muscle degeneration
\ua9 2024. The Author(s). Becker muscular dystrophy (BMD) is characterised by fiber loss and expansion of fibrotic and adipose tissue. Several cells interact locally in what is known as the degenerative niche. We analysed muscle biopsies of controls and BMD patients at early, moderate and advanced stages of progression using Hyperion imaging mass cytometry (IMC) by labelling single sections with 17 markers identifying different components of the muscle. We developed a software for analysing IMC images and studied changes in the muscle composition and spatial correlations between markers across disease progression. We found a strong correlation between collagen-I and the area of stroma, collagen-VI, adipose tissue, and M2-macrophages number. There was a negative correlation between the area of collagen-I and the number of satellite cells (SCs), fibres and blood vessels. The comparison between fibrotic and non-fibrotic areas allowed to study the disease process in detail. We found structural differences among non-fibrotic areas from control and patients, being these latter characterized by increase in CTGF and in M2-macrophages and decrease in fibers and blood vessels. IMC enables to study of changes in tissue structure along disease progression, spatio-temporal correlations and opening the door to better understand new potential pathogenic pathways in human samples
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