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101.
Lukas C. Buelens Vladimir V. Galvita Hilde Poelman Christophe Detavernier Guy B. Marin 《化学,工程师,技术》2016,88(11):1684-1692
The kinetics of redox reactions of iron oxide in oxygen carrier 50Fe2O3/MgAl2O4 are examined using different time‐resolved techniques. Reduction kinetics are studied by H2 temperature‐programmed reduction (H2‐TPR) monitored by time‐resolved in situ XRD. In contrast to conventional TPR, in situ XRD distinguishes the three‐stage reduction of Fe2O3 → Fe3O4 → FeO → Fe. It also shows that the oxidation of Fe → Fe3O4 by CO2 has no intermediate crystalline phases, explaining why its kinetics can easily be investigated by conventional CO2 temperature‐programmed oxidation (CO2‐TPO). A shrinking core model which takes into account solid state diffusion allows describing the experimental data. 相似文献
102.
A Novel Technology for Natural Gas Conversion by Means of Integrated Oxidative Coupling and Dry Reforming of Methane
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Dr. Joris W. Thybaut Prof. Guy B. Marin Dr. Claude Mirodatos Dr. Yves Schuurman Dr. Andre C. van Veen Prof. Vladislav A. Sadykov Dr. Helmut Pennemann Dr. Rainer Bellinghausen Prof. Leslaw Mleczko 《化学,工程师,技术》2014,86(11):1855-1870
A novel process concept for the oxidative coupling of methane followed by the oligomerization to liquids has been developed within the frame of the EU integrated project OCMOL. This technology is based on process intensification principles via cutting‐edge structured microreactor technology. It is also a fully integrated industrial process through the re‐use and the recycling of by‐products, in particular CO2, at every process stage. The focus of this contribution is on the reaction engineering aspects of the core steps, i.e., catalysts, kinetics and reactor design for the methane coupling and reforming. 相似文献
103.
Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells
Khaled Ben Messaoud Marie Buffire Guy Brammertz Hossam ElAnzeery Souhaib Oueslati Jonathan Hamon Bas J. Kniknie Marc Meuris Mosbah Amlouk Jef Poortmans 《Progress in Photovoltaics: Research and Applications》2015,23(11):1608-1620
The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu2ZnSnSe4 (CZTSe) thin‐film solar cells, by using a Cd2+ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se2 (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (RS) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
104.
Nicolas Vivas Guy Bourgeois Christiane Vitry Yves Glories Victor de Freitas 《Journal of the science of food and agriculture》1996,72(3):309-317
The composition of various commercial tannin extracts were determined by liquid secondary ion mass spectrometry (LSIMS). Spectra were obtained directly from tannin extracts without any pre-separation. Eight different tannin powders were analysed: three gallotannins (Chinese, Turkish, tara), three ellagitannins (sweet chestnut, pendunculata oak, sessile oak), one mixed hydrolysable tannin (myrabolans) and one proanthocyanidin (grape seeds). This method enabled the main molecules in these powders to be identified. 相似文献
105.
Verstrepen KJ Van Laere SD Vercammen J Derdelinckx G Dufour JP Pretorius IS Winderickx J Thevelein JM Delvaux FR 《Yeast (Chichester, England)》2004,21(4):367-377
The yeast alcohol acetyl transferase I, Atf1p, is responsible for the major part of volatile acetate ester production in fermenting Saccharomyces cerevisiae cells. Some of these esters, such as ethyl acetate and isoamyl acetate, are important for the fruity flavours of wine, beer and other fermented beverages. In order to reveal the subcellular localization of Atf1p and further unravel the possible physiological role of this protein, ATF1::GFP fusion constructs were overexpressed in brewer's yeast. The transformant strain showed a significant increase in acetate ester formation, similar to that of an ATF1 overexpression strain, indicating that the Atf1p-GFP fusion protein was active. UV fluorescence microscopy revealed that the fusion protein was localized in small, sphere-like organelles. These organelles could be selectively stained by the fluorescent dye Nile red, indicating that they contained high amounts of neutral lipids and/or sterols, a specific characteristic of yeast lipid particles. Purification of lipid particles from wild type and ATF1 deletion cells confirmed that the Atf1p-GFP fusion protein was located in these organelles. Furthermore, a clear alcohol acetyl transferase activity could be measured in the purified lipid particles of both wild type and transformed cells. The localization of Atf1p in lipid particles may indicate that Atf1p has a specific role in the lipid and/or sterol metabolism that takes place in these particles. 相似文献
106.
Microkinetic model for the pyrolysis of methyl esters: From model compound to industrial biodiesel
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Ruben De Bruycker Steven P. Pyl Marie‐Françoise Reyniers Kevin M. Van Geem Guy B. Marin 《American Institute of Chemical Engineers》2015,61(12):4309-4322
A tool for the generation of decomposition schemes of large molecules has been developed. These decomposition schemes contain radicals which can be eliminated from the model equations if both the μ‐hypothesis and the pseudosteady‐state approximation are valid. The reaction rate coefficients and thermodynamic parameters have been calculated by incorporating a comprehensive group additive framework. A microkinetic model for the pyrolysis of methyl esters with a carbon number of up to 19 has been generated using this tool. It is validated by comparing calculated and experimental yields of the pyrolysis of methyl decanoate and novel rapeseed methyl ester pyrolysis data in the temperature range from 800 to 1100 K and methyl ester partial pressure range from 1 × 10?3 to 1 × 10?2 MPa. This modeling frame work allows to not only assess the use of methyl ester mixtures as potential feedstock for olefin production but also their effect as blend‐in or trace impurity. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4309–4322, 2015 相似文献
107.
The intake of fat, saturated and monounsaturated FA (SFA and MUFA), and omega-6 and omega-3 PUFA has been estimated in 641
Belgian women (age 18-39 y). Their food intake was recorded using a 2-d food diary. The PUFA included were linoleic (LA),
alpha-linolenic (LNA), arachidonic (AA), eicosapentaeonoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) acids.
The mean total fat intake corresponded to 34.3% of total energy intake (E). The mean intake of the FA groups corresponded
to 13.7%, 13.1%, and 6.0% of E, for SFA, MUFA, and PUFA, respectively. The mean intake of LA was 5.3% of E and of LNA was
0.6% of E, with a mean LA/LNA ratio of 8.7. The mean intake of AA was 0.03% of E. The mean intake of EPA, DPA, and DHA was
0.4%, 0.01%, and 0.06% of E, respectively. According to the Belgian recommendations, the total fat and SFA intake was too
high for about three-quarters of the population. The mean LA and overall n-6 PUFA intake corresponded with the recommendation,
with part of the population exceeding the upper level. Conversely, the population showed a large deficit for LNA and n-3 PUFA.
The major food source for LA and LNA was fats and oils, followed by cereal products. The main sources of long-chain PUFA were
fish and seafood, and meat, poultry, and eggs. From a public health perspective, it seems desirable to tackle the problem
of low n-3 PUFA intake. 相似文献
108.
A series of in situ synchrotron X-ray diffraction experiments are performed during the stretching of weakly and highly vulcanized carbon black (CB), silica and grafted silica filled natural rubber sample (NR). Conversely to literature, Mullins effect observed after one stretching cycle modifies the strain induced crystallization (SIC) behaviour of the sample. The onset of crystallization is ruled by the strain amplification induced by the filler presence. Moreover, fillers (CB and silica) behave as additional crosslinks into NR network, through filler-rubber interactions that either accelerate or slow down the crystallization rate depending on NR matrix chemical crosslink density. This is consistent with the assumption that effective network density, which is due to chemical crosslinks, entanglements, and filler-rubber interactions, controls the crystallization rate. 相似文献
109.
Abhishek Dutta Rahul P. Ekatpure Geraldine J. Heynderickx Axel de Broqueville Guy B. Marin 《Chemical engineering science》2010,65(5):1678-1693
Computational fluid dynamics (CFD) simulations of the hydrodynamic behavior of rotating fluidized beds in static geometry (RFB-SG) are carried out for gas–solid flows. The rotating motion of the reactor bed is induced by the tangential injection of the gas along the circumference of the fluidization chamber. Steep gradients in the gas velocity fields both in radial and tangential direction generate turbulence. The radial and tangential drag forces fluidize the particle bed in both radial and tangential direction.An Eulerian two-fluid model is used. Gas phase turbulence is accounted for by a k–ε model adapted for rotational flows. The RFB-SG simulations provide guidelines for a design and operation with a high efficiency in gas–solid momentum transfer, excellent gas–solid separation and limited solids losses. Hydrodynamic variables like the centrifugal force, the injection pressure, the radial and tangential slip velocities, solids hold-up are calculated for both polymer particles (300 μm, 950 kg/m3, Geldart Group B) and glass beads (70 μm, 2500 kg/m3, Geldart Group A) to allow for a comparison among different fluidization chamber designs. Unstable bed behavior, like slugging and channeling, is also numerically predicted. 相似文献
110.
Sun-Xiao Zhang Ya-Ling He Guy Lauriat Wen-Quan Tao 《International Journal of Heat and Mass Transfer》2010,53(19-20):3977-3989
The effects of wall axial heat conduction in a conjugate heat transfer problem in simultaneously developing laminar flow and heat transfer in straight thick wall of circular tube with constant outside wall temperature are numerically investigated. The results show that the heat transfer process is most sensitive to wall-to-fluid conductivity ratio ksf, and when ksf ? 25 the increasing tube thickness and the decreasing ksf could make the inner wall surface approaching the uniform heat flux condition. It turns out that the basic function of the wall axial heat conduction for the cases studied is to unify the inner wall surface heat flux. 相似文献