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See detailGas chromatography-olfactometry analysis of beef meat originating from differently fed Belgian Blue, Limousin and Aberdeen Angus bulls
Machiels, D.; Istasse, Louis ULg; van Ruth, S. M.

in Food Chemistry (2004), 86(3), 377-383

The volatile compounds of cooked meats from differently fed Belgian Blue, Limousin and Aberdeen Angus bulls were isolated in a model mouth apparatus. Their odour activity was determined by gas ... [more ▼]

The volatile compounds of cooked meats from differently fed Belgian Blue, Limousin and Aberdeen Angus bulls were isolated in a model mouth apparatus. Their odour activity was determined by gas chromatography-olfactometry based on a detection frequency method. A total of thirty compounds possessed an odour activity in cooked beef meat. Significant influences of breed and diet on the development of the odour-active compounds of cooked beef meat were observed. The meat of Belgian Blue seemed to generate more odour-active compounds and to be more influenced by the feeding diet than the other breeds. This could be the consequence, at least in part, of its double-muscle condition. However, no obvious justifications could be given to explain the influence of the diet. Different chemical compositions are factors of importance for explaining the different aroma profiles between breeds, but some other parameters should also play an important role. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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See detailGas chromatography-olfactometry analysis of the volatile compounds of two commercial Irish beef meats
Machiels, D.; van Ruth, S. M.; Posthumus, M. A. et al

in Talanta (2003), 60(4), 755-764

The volatile flavour compounds of two commercial Irish beef meats (labelled as conventional and organic) were evaluated by gas chromatography-olfactometry and were identified by gas chromatography-mass ... [more ▼]

The volatile flavour compounds of two commercial Irish beef meats (labelled as conventional and organic) were evaluated by gas chromatography-olfactometry and were identified by gas chromatography-mass spectrometry. The volatile compounds were isolated in a model mouth system. Gas chromatography-olfactometry was performed by a group of eight assessors using the detection frequency methodology. The odours of the detected compounds were described as well. Eighty-one volatile compounds were identified, 11 compounds of which possessed odour activity in the first beef sample and 14 of which in the second meat sample. Ten volatile flavour compounds were common to both: methanethiol, dimethyl sulphide, 2-butanone, ethyl acetate, 2- and 3-methylbutanal, an unknown compound, 2-octanone, decanal and benzothiazole. Two unknown compounds were only detected in the first sample while 2,3-pentanedione, 4-methyl-3-penten-2-one, 2-heptanone, dimethyl trisulphide and nonanal were only perceived in the second beef. Significant differences in terms of detection frequency, odour characteristics and in nature of the volatile flavour compounds were emphasised between the two samples. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailGas concentrations in Barrow landfast sea ice: the winter/spring contrasts
Zhou, Jiayun ULg; Tison, Jean-Louis; Brabant, Frédéric et al

in Solas News (2011), 13(Summer), 22-23

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See detailGas exchange during storage and incubation of Avian eggs: Effects on embryogenesis, hatchability, chick quality and post-hatch growth
Onagbesan, O.; Bruggeman, V.; Smit, L. D. et al

in World's Poultry Science Journal (2007), 63(4), 557-573

Embryonic development is a dynamic process that requires a fine balance between several factors in order to achieve an optimum hatchability and chick quality. These factors include the background of the ... [more ▼]

Embryonic development is a dynamic process that requires a fine balance between several factors in order to achieve an optimum hatchability and chick quality. These factors include the background of the embryo, such as genetic line of the breeders, the age of the breeder, egg weight, and factors related to the environment in which the egg is stored and incubated, such as temperature, humidity, gas levels and altitude. Gas exchanges are of fundamental importance for embryonic development during incubation and may affect the livability of the embryo. This paper reviews the roles of the gaseous environment (i.e. O 2 and CO2) around hatching eggs during storage and during incubation and the effect it might have on the survival of the developing embryos and the chicks that hatch. The state of the art on the different attempts to establish the optimum requirements of different gases that promote the optimal developmental trajectories at different periods during incubation is presented. The roles and consequences of different levels of O2 and CO2 during storage and incubation on hatchability, incubation duration, hatching process, embryo growth, embryo mortality, organ development and morphology, metabolism, blood acid-base balance, chick quality and chick post-hatch growth are reviewed. © 2007 World's Poultry Science Association. [less ▲]

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See detailGas exchange in resting and exercising animals
Lekeux, Pierre ULg; Art, Tatiana ULg

in Lekeux, Pierre (Ed.) Pulmonary Function in Healthy, Exercising and Diseased Animals (1993)

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See detailGas Flow Simulations in a Structured Packing by Lattice Boltzmann Method
Beugre, Djomice; Calvo, Sébastien ULg; Crine, Michel ULg et al

Conference (2011, November 15)

Numerical simulations of gas flow between two sheets of plastic MellapakTM 250 Y are performed using Lattice Boltzmann methods in laminar and turbulent regimes. Results are compared with experimental ... [more ▼]

Numerical simulations of gas flow between two sheets of plastic MellapakTM 250 Y are performed using Lattice Boltzmann methods in laminar and turbulent regimes. Results are compared with experimental measurements and with known correlations. They are also compared with simulations using a classical CFD code. In all cases, the agreement is very good. [less ▲]

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See detailGas Flow Simulations in a Structured Packing by Lattice Boltzmann Method
Beugre, Djomice; Calvo, Sébastien ULg; Crine, Michel ULg et al

in Chemical Engineering Science (2011), 66

Numerical simulations of gas flow between two sheets of plastic MellapakTM 250 Y are performed using Lattice Boltzmann methods in laminar and turbulent regimes. Results are compared with experimental ... [more ▼]

Numerical simulations of gas flow between two sheets of plastic MellapakTM 250 Y are performed using Lattice Boltzmann methods in laminar and turbulent regimes. Results are compared with experimental measurements and with known correlations. They are also compared with simulations using a classical CFD code. In all cases, the agreement is very good. [less ▲]

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See detailGas injection test in the Callovo-Oxfordian claystone: data analysis and numerical modelling
De la Vaissière, Rémi; Gerard, Pierre; Radu, Jean-Pol ULg et al

in Geological Society, London, Special Publications Online First (2014)

This paper describes a field-scale experiment on gas transport mechanisms performed at Andra’s Underground Research Laboratory (URL) in a clay rock. The experimental layout consists of two parallel ... [more ▼]

This paper describes a field-scale experiment on gas transport mechanisms performed at Andra’s Underground Research Laboratory (URL) in a clay rock. The experimental layout consists of two parallel boreholes that are equipped with multiple packer completions isolating three intervals each, which have been continuously monitoring the pore pressure evolution of the clay rock. Nitrogen gas was injected in the middle test interval of one of the boreholes at increasing rates. The entire gas test comprised six periods of controlled gas injections, each fol-lowed by a shut-in pressure recovery phase. The experimental data are presented along with their interpretation by means of numerical modelling of two-phase flow of gas and water using different numerical codes and different geometrical approaches that include axisymmetric, half-space and full 3D models. An iterative modelling process was used to show step-by-step how an accu-rate description of each component of the experiment system produced a satisfactory reproduc-tion of the experimental data and an improved understanding of the relevant phenomena. For instance, the initial volume of remaining water in the test interval, and the presence of a damaged zone around the boreholes, was important for the models to obtain good agreement with the field data. [less ▲]

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See detailA gas micromechanical sensor based on surface plasmon resonance
Hastanin, Juriy ULg; Habraken, Serge ULg; Renotte, Yvon ULg et al

in Proceedings of SPIE (2008, October 02), 7116

We will present a new concept related to the micromechanical sensors for detecting the presence and concentration of chemical substances and/or biological organisms. A bi-dimensional array of micro ... [more ▼]

We will present a new concept related to the micromechanical sensors for detecting the presence and concentration of chemical substances and/or biological organisms. A bi-dimensional array of micro-cantilever coated by different types of sensing layer enables to identify a characteristic chemical composition of the gas in real-time mode. The selective molecular absorption by cantilever sensing layer will produce cantilever bending proportional to the concentration of molecules. To increase the gas sensor sensitivity, the SPR phenomenon is used for cantilever deflection monitoring. [less ▲]

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See detailGas migration in sea ice: from observations to modelling
Zhou, Jiayun ULg; Moreau, Sébastien; Vancoppenolle, Martin et al

Poster (2012, May 07)

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See detailGas Migration through Clay Barriers in the Context of Radioactive Waste Disposal: Numerical Modeling of an InSitu Gas Injection Test
Gerard, Pierre ULg; Radu, Jean-Pol ULg; Talandier, Jean et al

in Pijaudier-Cabot, Gilles; Pereira (Eds.) Geomechanics in CO2 Storage Facilities (2012)

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See detailGas Phase Fullerene Anions Hydrogenation by Methanol Followed by IRMPA Dehydrogenation
Greisch, Jean-François ULg; Leyh, Bernard ULg; Remacle, Françoise ULg et al

in Journal of the American Society for Mass Spectrometry (2010), 21(1), 117-126

The characterization in the gas phase of the mechanisms responsible for hydride formation can <br />contribute to the development of new materials for hydrogen storage. The present work <br />provides ... [more ▼]

The characterization in the gas phase of the mechanisms responsible for hydride formation can <br />contribute to the development of new materials for hydrogen storage. The present work <br />provides evidence of a hydrogenation-dehydrogenation catalytic cycle for C60 anions in the <br />gas phase using methanol vapor at room temperature as hydrogen donor. [less ▲]

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See detailGas Phase Thermal Denaturation of an Oligonucleotide Duplex and Its Complexes with Minor Groove Binders
Gabelica, Valérie ULg; Rosu, Frédéric ULg; Houssier, Claude ULg et al

in Rapid Communications in Mass Spectrometry : RCM (2000), 14(6), 464-467

Electrospray ionization with in-source collisionally induced dissociation has been used to probe the gas phase stability of an oligonucleotide duplex and its complexes with some minor groove binding drugs ... [more ▼]

Electrospray ionization with in-source collisionally induced dissociation has been used to probe the gas phase stability of an oligonucleotide duplex and its complexes with some minor groove binding drugs. On the basis of the arguments developed in detail by Drahos et al. (J. Mass Spectrom. 1999; 34:1373), this type of experiment can also be described as 'thermal denaturation in the gas phase'. We found that the gas phase denaturation curves were very similar to the solution phase denaturation curves determined by the traditional UV spectrophotometric method and, by analogy with the melting temperature T(m) which characterizes the stability in solution, we define a melting voltage V(m) to characterize the stability in the gas phase. A comparison of the T(m) and V(m) relative values suggests that the structure of the complexes is conserved during the electrospray process which transfers the ions from the solution to the gas phase. [less ▲]

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See detailGas Sensing with Au-Decorated Carbon Nanotubes
Zanolli, Zeila ULg; Leghrib, Radouane; Felten, Alexandre et al

in ACS Nano (2011), 5(6), 4592-4599

The sensing properties of carbon nanotubes (CNTs) decorated with gold nanopar- ticles have been investigated by means of combined theoretical and experimental approaches. On one hand, first-principles and ... [more ▼]

The sensing properties of carbon nanotubes (CNTs) decorated with gold nanopar- ticles have been investigated by means of combined theoretical and experimental approaches. On one hand, first-principles and nonequilibrium Green's functions techniques give access to the microscopic features of the sensing mechanisms in individual nanotubes, such as electronic charge transfers and quantum conductances. On the other hand, drop coating deposition of carbon nanotubes decorated with gold nanoparticles onto sensor substrates and their characterization in the detection of pollutants such as NO2, CO, and C6H6 provide insight into the sensing ability of nanotube mats. Using the present combined approaches, the improvement in the detection of some specific gases (NO2 and CO) using Au-functionalized nanotubes is explained. However, for other gases such as C6H6, the Au nanoparticles do not seem to play a crucial role in the sensing process when compared with pristine CNTs functionalized with oxygen plasma. Indeed, these different situations can be explained by identifying the relationship between the change of resistance (macroscopic feature) and the shift of the Fermi level (microscopic feature) after gas adsorption. The understanding of the sensing ability at the atomic level opens the way to design new gas sensors and to tune their selectivity by predicting the nature of the metal that is the most appropriate to detect specific molecular species. [less ▲]

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See detailGas sensor array applied to the monitoring of biogas process
Adam, Gilles ULg; Lemaigre, Sébastien; Romain, Anne-Claude ULg et al

Conference (2011, May)

There is a lack of simple online monitoring system to control the performances of biogas reactors. The electronic nose technology appears to be an adapted device to deliver fast information about process ... [more ▼]

There is a lack of simple online monitoring system to control the performances of biogas reactors. The electronic nose technology appears to be an adapted device to deliver fast information about process disturbances in anaerobic reactors as it is adequate for online monitoring. In this study, twelve anaerobic mini-reactors were supervised with a home-made e-nose to observe process reaction in relation to organic overloads events. Usually, to avoid overload situations, on farms reactors are not fed at maximum load capacity, resulting in non optimized biogas production. The objective of the experiment was to determine if the gas sensors array feature can be related to the process state and if an indirect state variable, giving early warning of process faults, can be derived from the e-nose response. <br />The results demonstrated that focusing on gas phase of anaerobic reactors with a simple device composed of an array of non-specific gas sensors helped in the warning of disorders of the anaerobic digestion process. Mahalanobis distance from a cautious feeding group (group of observations indicating a good process) can be used as an indirect variable to evaluate the intensity of the state disorder. Euclidean distance has been also calculated but it was less informative than the Mahalanobis distance. [less ▲]

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See detailGas transfer velocities of CO2 in three European estuaries (Randers Fjord, Scheldt and Thames)
Borges, Alberto ULg; Delille, Bruno ULg; Schiettecatte, L. S. et al

Poster (2003, April)

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See detailGas transfer velocities of CO2 in three European estuaries (Randers Fjord, Scheldt and Thames)
Borges, Alberto ULg; Delille, Bruno ULg; Schiettecatte, Laure-Sophie et al

in Limnology & Oceanography (2004), 49(5), 1630-1641

We measured the flux of CO2 across the air–water interface using the floating chamber method in three European estuaries with contrasting physical characteristics (Randers Fjord, Scheldt, and Thames). We ... [more ▼]

We measured the flux of CO2 across the air–water interface using the floating chamber method in three European estuaries with contrasting physical characteristics (Randers Fjord, Scheldt, and Thames). We computed the gas transfer velocity of CO2 (k) from the CO2 flux and concomitant measurements of the air–water gradient of the partial pressure of CO2 (pCO2). There was a significant linear relationship between k and wind speed for each of the three estuaries. The differences of the y-intercept and the slope between the three sites are related to differences in the contribution of tidal currents to water turbulence at the interface and fetch limitation. The contribution to k from turbulence generated by tidal currents is negligible in microtidal estuaries such as Randers Fjord but is substantial, at low to moderate wind speeds, in macrotidal estuaries such as the Scheldt and the Thames. Our results clearly show that in estuaries a simple parameterization of k as a function of wind speed is site specific and strongly suggest that the y-intercept of the linear relationship is mostly influenced by the contribution of tidal currents, whereas the slope is influenced by fetch limitation. This implies that substantial errors in flux computations are incurred if generic relationships of the gas transfer velocity as a function of wind speed are employed in estuarine environments for the purpose of biogas air–water flux budgets and ecosystem metabolic studies. [less ▲]

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See detailGas Transfer Velocity as a critical variable in coastal ecosystem metabolism studies
Gazeau, F.; Gattuso, J.–P.; Frankignoulle, M. et al

Poster (2005, May)

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See detailGas-dynamic description of electrostatic solitons
Verheest, F.; Cattaert, Tom ULg; Lakhina, G. S. et al

in Journal of Plasma Physics (2004), 70

The nonlinear propagation of electrostatic solitary structures in unmagnetized multispecies plasmas is studied in the wave frame, where they are stationary, via the recently developed McKenzie approach as ... [more ▼]

The nonlinear propagation of electrostatic solitary structures in unmagnetized multispecies plasmas is studied in the wave frame, where they are stationary, via the recently developed McKenzie approach as an alternative to the more usual Sagdeev pseudo-potential method. This way of looking at the problem brings out the gas-dynamic aspects, which then allow a straightforward characterization of the solitary wave possibilities in terms of the species' own sonic points and of the global charge neutral points. A qualitative discussion of ion-, dust- and electron-acoustic solitary waves is given in terms of these concepts and the results are contrasted with those obtained by other methods. Ion-acoustic solitons can be shown to always be compressive, without invoking simplifying assumptions such as cold ions or Boltzmann electrons. Beam-plasmas can also be studied, as in the elect non-acoustic solitary wave model for the spiky structures of the broadband electrostatic noise observed in the auroral regions of the Earth's magnetosphere. Such solitons always show a potential dip. [less ▲]

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