Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailMicrowave-assisted thermochemical and primary hydrolytic conversions of lignocellulosic resources: a review
Richel, Aurore ULg; Jacquet, Nicolas ULg

in Biomass Conversion and Biorefinery (in press)

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has ... [more ▼]

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has nowadays opened new vistas for the production of energy, biofuels and chemicals. In this literature review, microwave technology is described as an original heating source either for the thermochemical conversions (at temperatures up to 400°C) of lignocellulose into biofuels or the pretreatment (below 400°C) and further hydrolysis of lignocellulose into bioethanol and other valuable chemicals. Advantages of microwave approaches include a commonly observed acceleration in reaction rate and improved selectivities and yields. [less ▲]

Detailed reference viewed: 20 (10 ULg)
Full Text
See detailMicrowave-assisted transformations of agroresources: an example of green chemistry
Richel, Aurore ULg

in SciTopics-Research summarises by Experts (2010)

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as a promising renewable alternative. Alongside its traditional involvement in the agro-food, the ... [more ▼]

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as a promising renewable alternative. Alongside its traditional involvement in the agro-food, the biomass has nowadays opened new vistas in the non-food sector. Indeed, original products and structures, potentially biodegradable, are proposed as substitutes for conventional petrochemical derivatives. The steady rise of oil prices, on the one hand, and the implementation of a new European legislation (REACH: Registration, Evaluation and Authorization of Chemicals), on the other hand, have only help to boost the academic and industrial research in this area. In this context, microwave-mediated synthesis has progressively emerged as a green chemistry technology. Application of microwaves (MW) as a non conventional heating source finds a plethora of illustrations in the field of organic synthesis. Microwaves usually accelerate chemical processes, while offering improved yields and selectivities. MW heating enables reactions under solventless conditions, providing unique chemical pathways, with special advantages such as ease of manipulation and reduction (or prevention) of pollution "at source". Various reactions and processes can be applied to transform lignocellulosic raw materials into valuable fuels and chemicals. Selected examples of strategical modifications of renewable biomass feedstocks via activation by microwave irradiation are proposed herein. [less ▲]

Detailed reference viewed: 30 (4 ULg)
Full Text
See detailMicrowave-assisted transformations of agroresources: an example of green chemistry
Richel, Aurore ULg; Laurent, Pascal ULg; Paquot, Michel ULg

Report (2010)

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as a promising renewable alternative. Alongside its traditional involvement in the agro-food, the ... [more ▼]

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as a promising renewable alternative. Alongside its traditional involvement in the agro-food, the biomass has nowadays opened new vistas in the non-food sector. Indeed, original products and structures, potentially biodegradable, are proposed as substitutes for conventional petrochemical derivatives. The steady rise of oil prices, on the one hand, and the implementation of a new European legislation (REACH: Registration, Evaluation and Authorization of Chemicals), on the other hand, have only help to boost the academic and industrial research in this area. In this context, microwave-mediated synthesis has progressively emerged as a green chemistry technology. Application of microwaves (MW) as a non conventional heating source finds a plethora of illustrations in the field of organic synthesis. Microwaves usually accelerate chemical processes, while offering improved yields and selectivities. MW heating enables reactions under solventless conditions, providing unique chemical pathways, with special advantages such as ease of manipulation and reduction (or prevention) of pollution "at source". Various reactions and processes can be applied to transform lignocellulosic raw materials into valuable fuels and chemicals. Selected examples of strategical modifications of renewable biomass feedstocks via activation by microwave irradiation are proposed herein. [less ▲]

Detailed reference viewed: 42 (7 ULg)
See detailMicrowave-assisted transformations of carbohydrates
Richel, Aurore ULg

Report (2010)

This reports deals with the involvment of microwaves for the conversion of renewable feedstocks, and in particlar for the tranfsormation of monosaccharides and cellulose into high added value materials.

Detailed reference viewed: 21 (3 ULg)
Full Text
See detailMicrowave-assisted transformations of carbohydrates
Richel, Aurore ULg; Wathelet, Jean-Paul ULg; Paquot, Michel ULg

in SciTopics / Research Summaries by Experts (2010)

Detailed reference viewed: 52 (11 ULg)
Full Text
See detailMicrowave-Enhanced Ruthenium Catalysed Atom Transfer Radical Additions
Richel, Aurore ULg; Leclerc, Alain; Demonceau, Albert ULg et al

Poster (2005)

Detailed reference viewed: 16 (6 ULg)
Full Text
Peer Reviewed
See detailMicrowave-enhanced ruthenium-catalysed atom transfer radical additions
Borguet, Yannick ULg; Richel, Aurore ULg; Delfosse, Sbastien et al

in Tetrahedron Letters (2007), 48(36), 6334-6338

The first monomode microwave-assisted atom transfer radical additions (ATRA) of carbon tetrachloride to various olefins were successfully performed, affording the adducts with almost quantitative yields ... [more ▼]

The first monomode microwave-assisted atom transfer radical additions (ATRA) of carbon tetrachloride to various olefins were successfully performed, affording the adducts with almost quantitative yields in less than 10 min at 160 'C. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 39 (17 ULg)
See detailMicrowave-treatment of frozen wood packaging material
Henin, Jean-Marc; Bauduin, Aline; Leyman, Michaël ULg et al

Conference (2012, July 12)

As part of the wood packaging material (WPM) regulation in international trade, the dielectric heating (DH) is soon to be included in ISPM15 (IPPC 2009) as an approved phytosanitary treatment. It has been ... [more ▼]

As part of the wood packaging material (WPM) regulation in international trade, the dielectric heating (DH) is soon to be included in ISPM15 (IPPC 2009) as an approved phytosanitary treatment. It has been considered that when using dielectric radiation (i.e. microwaves or radiofrequencies), reaching 60°C or more throughout the entire profile of the wood during at least 60s (i.e. 60°C/60s) ensures the eradication of any noxious organism present in the wood. Regarding the treatment itself, the main requirements mentioned in the draft of ISPM15 Annex 1 (IPPC 2011) concern the way to achieve “uniformity of heating” as well as the treatment duration, which must not exceed 30min. Concerning wood characteristics, the only restriction to the DH concerns the thickness of the wood pieces, which must not exceed 20cm; no other restriction exists regarding wood moisture content, density or initial temperature. As reported in the draft of ISPM15 Annex 1, it is generally considered that “when using microwaves as a heating source, the coldest part of the wood is the surface”. This statement implies that achieving 60°C (or more) during 60s at the surface of the wood should guarantee compliance with IPPC requirements (i.e. 60°C throughout the profile of the wood). However, since ice and liquid water exhibit very different properties towards microwaves, initially frozen wood (9cmX9cm and 17cmX17cm in cross-section) was irradiated in a 28.8 kW microwave oven (2.45GHz) in order to assess whether achieving 60°C/60s at the surface of less than 20cm-thick planks ensures higher core temperatures. The temperature pattern observed after the treatment was compared with the one observed after the treatment of initially thawed wood pieces. It was observed that, in some conditions, initially frozen pieces exhibit inside temperature (much) lower than 60°C, despite complying with 60°C/60s all over the surface of the wood. These results show that when wood is heated with microwaves, its coldest part may not be the surface. Our results also strongly suggest that the impact of wood properties on post-treatment temperature pattern should be further investigated in order to better identify the limits of the DH (at least on frozen wood). [less ▲]

Detailed reference viewed: 30 (7 ULg)
Full Text
Peer Reviewed
See detailMicrowear and Residue Analysis in Perspective: the contribution of ethnoarchaeological evidence
Rots, Veerle ULg; Williamson, Bonny

in Journal of Archaeological Science (2004), 31

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailA micro–macro approach of permeability evolution in rocks excavation damaged zones
Levasseur, Séverine ULg; Collin, Frédéric ULg; Charlier, Robert ULg et al

in Computers & Geotechnics (2013), 49

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress ... [more ▼]

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress perturbation around the excavation could lead to a significant increase of the permeability physically due to diffuse and/or localized microcracks growth in the material. In the present study, we investigate microcracks-induced damage processes together with the subsequent modification in permeability. The proposed approach is based on a homogenization-based upper bound extended to the context of micro-cracked media in presence of initial stress. Application of this approach is done on a borehole excavation problem related to the Selfrac in situ experiments on Opalinus Clay. Although, the model fails to quan-titatively account for the in situ permeability change (which may also originated from existing macro-fractures), its prediction shows a significant evolution of the material permeability around the borehole. This is in qualitative agreement with available data. [less ▲]

Detailed reference viewed: 30 (4 ULg)
Full Text
Peer Reviewed
See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mouhamd ULg; Beghin, Jérémie ULg; le roux, Gael et al

in Climate of the Past (2013), 9(2889-2928,),

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes ... [more ▼]

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes, were determined by HR-ICP-MS and MC-ICP-MS respectively, along a  6 m peat section covering 5300 years, from 2000 to 7300 cal.BP dated by the 14C method. Changes in REE concentration in the peat correlate with those of Ti, Al, Sc and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4.0 g m-2 yr-1. The highest dust fluxes were observed from 2750 to 2550 cal.BP and from 5150 to 4750 cal.BP and correspond to cold periods. The Nd values show a large variability from -13 to –5, identifying three major sources of dusts: local soils, distal volcanic and desert particles. [less ▲]

Detailed reference viewed: 45 (17 ULg)
Peer Reviewed
See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mouhamd ULg; Le Roux, Gael; Piotrowska, Natalia et al

Poster (2012, June)

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the ... [more ▼]

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the variations in peat composition reflect changes in precipitation and temperature. Peat has been used as an archive to reconstruct climate change over the Holocene (e.g., Shotyk et al., 1998; Sapkota et al., 2006). To characterize the climate in Belgium, a 570 cm-long core from Misten peat bog was studied. Several radiocarbon ages allow to define an accurate age model, the peat core represents 5500 years of record. The analyses of REE and lithogenic element contents, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS. Peat humification, C/N ratio, ash content and bulk density were used to evaluate local hydroclimatic conditions. The dust deposition ranges from 0.03 to 4 g m -2 yr -1. As a first observation the highest rates of atmospheric dust deposition correspond to cold periods. The Nd values show large variability, between +1 to –22, identifying three major sources of dusts falling into the peat: local soils, distal volcanic and desert particles. Further studies are in progress to better identify the main forcing factor on the evolution of the atmospheric dust deposition over the Holocene. [less ▲]

Detailed reference viewed: 27 (6 ULg)
Full Text
Peer Reviewed
See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mouhamd ULg; Fagel, Nathalie ULg; Le Roux, Gael et al

Poster (2012, June 28)

The Misten peat bog representing 7.5 m of peat accumulation in the Hautes-Fagnes Plateau, Belgium, provides a record of Rare Earth Elements (REE) deposition since more than 7000 years. The analyses of REE ... [more ▼]

The Misten peat bog representing 7.5 m of peat accumulation in the Hautes-Fagnes Plateau, Belgium, provides a record of Rare Earth Elements (REE) deposition since more than 7000 years. The analyses of REE and lithogenic element concentrations, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS, respectively in peat layers previously dated by 210Pb and 14C. REE concentration variations in peat samples are correlated with Ti, Zr and Sc that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs [1] and can be used as tracers of dust deposition. Peat humification, C/N ratio, ash content and bulk density were used to evaluate hydroclimatic conditions. The Nd values show large variability, between +1 to –22, identifying three major sources of dusts falling into the peat: local soils, distal volcanic and desert particles. More recently, industrial emissions provide a fourth source of dusts [2], which is also clearly recorded in the last 200 years of the Misten peat profile. [less ▲]

Detailed reference viewed: 34 (16 ULg)
Full Text
Peer Reviewed
See detailMid infrared and fluorescence spectroscopies coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems
Karoui, Romdhane; Hammami, Moncef; Rouissi, Hamadi et al

in Food Chemistry (2011), 127(2), 743-748

Mid infrared spectroscopy (MIR) combined with multivariate data analysis was used to discriminate between ewes milk samples according to their feeding systems (controls, ewes fed scotch bean and ewes fed ... [more ▼]

Mid infrared spectroscopy (MIR) combined with multivariate data analysis was used to discriminate between ewes milk samples according to their feeding systems (controls, ewes fed scotch bean and ewes fed soybean). The MIR spectra were scanned throughout the first 11 weeks of the lactation stage. When factorial discriminant analysis (FDA) with leave one-out cross-validation was applied, separately, to the three spectral regions in the MIR (i.e. 3000-2800, 1700-1500 and 1500-900 cm(-1)), the classification rate was not satisfactory. Therefore, the first principal component (PCs) scores (corresponding to 3, 10 and 10 for, respectively, the 3000-2800, 1700-1500 and 1500-900 cm(-1)) of the principal component analysis (PCA) extracted from each of the data sets were pooled (concatenated) into a single matrix and analysed by FDA. Correct classification amounting to 71.7% was obtained. Finally, the same procedure was applied to the MIR and fluorescence data sets and 98% of milk samples were found to be correctly classified. Milk samples belonging to control and soybean groups were 100% correctly classified. Regarding milk samples originating from the scotch bean group, only 2 out of 33 samples were misclassified. It was concluded that concatenation of the data sets collected from the two spectroscopic techniques is an efficient tool for authenticating milk samples according to their feeding systems, regardless of the lactation stage. (C) 2011 Published by Elsevier Ltd. [less ▲]

Detailed reference viewed: 69 (21 ULg)
Full Text
See detailMid-Famennian cryptalgal-sponge crinoidal mud mounds and oolitic ironstones of the Limbourg-Dolhain area (Verviers Synclinorium, Eastern Belgium): Stop 2.
Dreesen, Roland; Marion, Jean-Marc ULg; Poty, Edouard ULg

Scientific conference (1993, June 09)

After the mass extinction of colonial reefs in the Ardennes at the Frasnian-Famennian boundary, (crypt)algal-sponge-crinoidal mud mounds suddenly appeared during the mid-Famennian time (Early-Late ... [more ▼]

After the mass extinction of colonial reefs in the Ardennes at the Frasnian-Famennian boundary, (crypt)algal-sponge-crinoidal mud mounds suddenly appeared during the mid-Famennian time (Early-Late marginifera Zone) in the Verviers Synclinorium (Eastern Belgium). These carbonate buildups represent the first reported occurrence of mud mounds in the latest Upper Devonian of Western Europe. The mounding sites for the mud mounds (locally known as "the Marbre rouge à crinoïdes de Baelen") are developed on a block-faulted basement. [less ▲]

Detailed reference viewed: 45 (5 ULg)
Full Text
See detailMid-FIR Properties of ELAIS Sources
Marquez, I.; Masegosa, J.; Morel, Thierry ULg et al

in The Promise of the Herschel Space Observatory (2001, July 01)

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can ... [more ▼]

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can generally be well fitted by a predominant cirrus component plus a modest starburst contribution. Follow-up spectroscopy has shown that all the objects are emission-line galaxies but without a very intense star formation event. Most of the galaxies analyzed by means of optical R band photometry result to host an important exponential disk component, in good agreement with the SED IR modelling. We note that galaxies with morphological signs of perturbations seem to show slightly higher f[SUB]15[/SUB]/f[SUB]6.7[/SUB] ratios, indicating that star formation could be more important in them. One of the objects is a broad-line, radio-quiet quasar at z=1.099; its spectral energy distribution indicates that it is a hyperluminous infrared galaxy (HLIG), the first HLIG detected in the ELAIS areas. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailMid-infrared prediction of bovine milk fatty acids across multiple breeds, production systems, and countries
Soyeurt, Hélène ULg; Dehareng, ; Gengler, Nicolas ULg et al

in Journal of Dairy Science (2011), 94

Increasing consumer concern exists over the relationship between food composition and human health. Because of the known effects of fatty acids on human health, the development of a quick, inexpensive ... [more ▼]

Increasing consumer concern exists over the relationship between food composition and human health. Because of the known effects of fatty acids on human health, the development of a quick, inexpensive, and accurate method to directly quantify the fatty acid (FA) composition in milk would be valuable for milk processors to develop a payment system for milk pertinent to their customer requirements and for farmers to adapt their feeding systems and breeding strategies accordingly. The aim of this study was (1) to confirm the ability of mid-infrared spectrometry (MIR) to quantify individual FA content in milk by using an innovative procedure of sampling (i.e., samples were collected from cows belonging to different breeds, different countries, and in different production systems); (2) to compare 6 mathematical methods to develop robust calibration equations for predicting the contents of individual FA in milk; and (3) to test interest in using the FA equations developed in milk as basis to predict FA content in fat without corrections for the slope and the bias of the developed equations. In total, 517 samples selected based on their spectral variability in 3 countries (Belgium, Ireland, and United Kingdom) from various breeds, cows, and production systems were analyzed by gas chromatography (GC). The samples presenting the largest spectral variability were used to calibrate the prediction of FA by MIR. The remaining samples were used to externally validate the 28 FA equations developed. The 6 methods were (1) partial least squares regression (PLS); (2) PLS + repeatability file (REP); (3) first derivative of spectral data + PLS; (4) first derivative + REP + PLS; (5) second derivative of spectral data + PLS; and (6) second derivative + REP + PLS. Methods were compared on the basis of the crossvalidation coefficient of determination (R2cv), the ratio of standard deviation of GC values to the standard error of cross-validation (RPD), and the validation coefficient of determination (R2v). The third and fourth methods had, on average, the highest R2cv, RPD, and R2v. The final equations were built using all GC and the best accuracy was observed for the infrared predictions of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1 trans, C18:1 cis-9, C18:1 cis, and for some groups of FA studied in milk (saturated, monounsaturated, unsaturated, short-chain, medium-chain, and long-chain FA). These equations showed R2cv greater than 0.95. With R2cv equal to 0.85, the MIR prediction of polyunsaturated FA could be used to screen the cow population. As previously published, infrared predictions of FA in fat are less accurate than those developed from FA content in milk (g/dL of milk) and no better results were obtained by using milk FA predictions if no corrections for bias and slope based on reference milk samples with known contents of FA were used. These results indicate the usefulness of equations with R2cv greater than 95% in milk payment systems and the usefulness of equations with R2cv greater than 75% for animal breeding purposes. [less ▲]

Detailed reference viewed: 67 (43 ULg)
Full Text
See detailMid-infrared prediction of cheese yield from milk and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Troch, Thibault ULg; Vanden Bossche, Sandrine et al

in Book of Abstracts of the 64th Annual Meeting of the European Federation of Animal Science (2013, August)

Detailed reference viewed: 20 (6 ULg)
Full Text
See detailMid-infrared prediction of cheese yield from milk and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Troch, Thibault ULg; Vanden, Bossche et al

Conference (2013, August 29)

Detailed reference viewed: 25 (13 ULg)