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See detailGeophysical characterization and monitoring of a municipal solid waste landfill
Dumont, Gaël ULg

Doctoral thesis (2017)

During this thesis, we aimed at demonstrating the value of geophysical methods for a waste deposit characterization in the context of landfill mining, both for energy and raw materials valorization. Our ... [more ▼]

During this thesis, we aimed at demonstrating the value of geophysical methods for a waste deposit characterization in the context of landfill mining, both for energy and raw materials valorization. Our preliminary analysis of the literature revealed that a multi-scale and multi-method investigation strategy was required. We also noticed an increasing interest in geoelectrical methods for the waste water content estimation, and for the monitoring of water content changes due to infiltration through the cover layer and water recirculation operation in bioreactor landfills. Firstly, we used the electromagnetic (EM) and magnetic mapping methods, quick and cost effective, to determine the site horizontal boundaries of our test-landfill. We combined the Horizontal to Vertical Noise Spectral Ratio (HVNSR) and the Multichannel Analysis of Surface Waves (MASW) seismic methods to estimate the thickness of this particularly deep deposit site. We also used the electrical resistivity tomography (ERT) to estimate the depth to water table and characterize the humidity of the unsaturated zone. Secondly, we investigated the suitability of geoelectrical methods (ERT, and borehole EM) to obtain spatially distributed information over the waste water content. For this purpose, petrophysical laws (established with laboratory experiments on waste samples) controlling the effects of water content, density and temperature on the bulk electrical resistivity of humid waste were established. Thirdly, we used numerical simulations to highlight several pitfalls occurring during the ERT monitoring of fresh water infiltration through a landfill cover layer. The effects on the interpretation of electrical resistivity changes of the ERT resolution, the background condition heterogeneity, the uncertainty on water content computation, and the often neglected dilution, were considered to extract the maximum information from the data and avoid over-interpretation. Lastly, we combined the ERT and the distributed temperature monitoring methods to evaluate the efficiency of horizontal drains, which are commonly used to regulate water content in a bioreactor. This tools provided us with valuable insight on the drain design suitability (diameter, depth, length, injected volume, etc.), the injected water flow behavior (waste anisotropy, heterogeneity, and the effect of vertical gas wells), and the humidification of the dry waste material efficiency. Taken together, our results have shown that geophysics represents a valuable approach for landfill investigation, provided that a special care is given to the data analysis. We thus finally discussed several interpretations limitation and proposed some insights to overcome them. [less ▲]

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See detailThe soundscape of Arctic Charr spawning grounds in lotic and lentic environments: can passive acoustic monitoring be used to detect spawning activities?
Bolgan, Marta ULg; O'Brien, Joanne; Chorazyczewska, Emilia et al

in Bioacoustics (2017)

The aims of this study were to (i) assess the efficacy of passive acoustic monitoring (PAM) for detecting Arctic Charr at their spawning grounds and (ii) characterize the overall acoustic soundscape of ... [more ▼]

The aims of this study were to (i) assess the efficacy of passive acoustic monitoring (PAM) for detecting Arctic Charr at their spawning grounds and (ii) characterize the overall acoustic soundscape of these sites. PAM was carried out over three Arctic Charr spawning grounds in the UK, one lotic and two lentic. 24-h cycles of recordings were collected prior to and during the Arctic Charr spawning season, which was determined from data returns by simultaneous net monitoring. Acoustic analysis consisted of manual quantification of sound sources, Acoustic Complexity Index (ACI) calculation and spectral analysis in 1/3 octave band (SPL; dB re 1 μPa). In the lotic spawning ground, prior to the beginning of Arctic Charr spawning, SPL and ACI showed a restricted range of variation throughout the 24-h, while during spawning the night values of SPL and ACI were found to significantly increase, concurrently with the rate of gravel noise induced by fish spawning activities and fish air passage sounds. Both prior to and during the Arctic Charr run, the lentic soundscape was characterized by diel variation due to the daytime presence of anthropogenic noise and the night-time presence of insect calls, while only a few occurrences of fish air passage sounds and gravel noise were recorded. These findings suggest that PAM over Arctic Charr spawning grounds could provide meaningful information to be used in developing management plans for this threatened species, such as determining the location and time of arrival, diel pattern and length of spawning activities. [less ▲]

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See detailModel-Based Optimization of the Medium Refreshment Regime During Neotissue Growth in a Perfusion Bioreactor
Mehrian, Mohammad ULg; guyot, Yann; Papantoniou, Ioannis et al

Scientific conference (2017, January 08)

Computational models are interesting tools to facilitate the translation from the laboratory to the patient. In regenerative medicine, computer models describing bioprocesses taking place in bioreactor ... [more ▼]

Computational models are interesting tools to facilitate the translation from the laboratory to the patient. In regenerative medicine, computer models describing bioprocesses taking place in bioreactor environment can assist in designing process conditions leading to robust and economically viable products. In this study we present a low-cost computational model describing the neotissue (cells + extracellular matrix) growth in a perfusion bioreactor set-up. The neotissue growth is influenced by the geometry of the scaffold, the flow-induced shear stress and a number of metabolic factors. After initial model validation, a Genetic Algorithm optimization technique is used to find the best medium refreshment regime (frequency and percentage of medium replaced) resulting in a maximal amount of neotissue being produced in the scaffold in a 28 days of culture period. [less ▲]

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See detailFlow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units
Zhang, Ji; Desideri, Adriano ULg; Ryhl Kaern, Martin et al

in International Journal of Heat & Mass Transfer (2017), 108

The optimal design of the evaporator is one of the key issues to improve the efficiency and economics of organic Rankine cycle units. The first step in studying the evaporator design is to understand the ... [more ▼]

The optimal design of the evaporator is one of the key issues to improve the efficiency and economics of organic Rankine cycle units. The first step in studying the evaporator design is to understand the thermal- hydraulic performance of the working fluid in the evaporator of organic Rankine cycles. This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydroflu- oroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected as the working fluids. The heat transfer coefficients and pressure drops of the three working fluids were measured with varying saturation temperatures, mass fluxes, heat fluxes and outlet vapour qualities, which range from 60 C to 80 C, 86 kg/m2 s to 137 kg/m2 s, 9.8 kW/m2 to 36.8 kW/m2 and 0.5 to 1, respectively. The working con- ditions covered relatively high saturation temperatures (corresponding reduced pressures of 0.35–0.74), which are prevailing in organic Rankine cycles yet absent in the open literature. The experimental data were compared with existing correlations, and new correlations were developed that are more suitable for evaporation in organic Rankine cycles. The experimental results indicate that heat transfer coefficients are strongly dependent upon the heat flux and saturation temperature. Moreover, the results suggest bet- ter thermal-hydraulic performance for R1234yf than the other two working fluids at the same saturation temperatures. With the new heat transfer and pressure drop correlations, agreements within ±25% were obtained for experimental data in similar experiments with high saturation temperatures. [less ▲]

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See detailMacroevolutionary patterns in sea breams, emperors and allies (Sparoidea, Acanthomorpha)
Santini, Francesco; Olivier, Damien ULg; Frederich, Bruno ULg

Poster (2017, January 07)

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See detailPollen nutrients better explain bumblebee colony development than pollen diversity
Moerman, Romain; Vanderplanck, Maryse ULg; Fournier, Denis et al

in Insect Conservation and Diversity (2017)

1. Bumblebees are valuable pollinators of numerous wild and cultivated plants. They can forage on variable pollen resources. As some pollen species lack particular nutrients or have global low nutritional ... [more ▼]

1. Bumblebees are valuable pollinators of numerous wild and cultivated plants. They can forage on variable pollen resources. As some pollen species lack particular nutrients or have global low nutritional quality, it has been suggested that bumblebees mix their pollen incomes to ensure a global balanced diet. The hypothesis that a mixed pollen diet better supports bumblebee colony development than a single pollen diet has been poorly explored. 2. We compared the impact of mono-, di- and trifloral diets on microcolony development of Bombus terrestris using three pollen resources with different nutrient contents (Cytisus scoparius, Erica sp. and Sorbus aucuparia) as well as their mixes. Nine parameters (e.g. pollen efficacy: total weight of larvae/total weight of pollen collection) were used to compare the microcolony performances. Moreover, we measured the influence of the pollen diversity and nutritional composition on relevant parameters. 3. We showed that microcolonies can potentially better develop on mixed pollen diets, but single pollen diet can also be as good as mixed pollen diet. Moreover, the sterol concentration appeared as a key factor to establish the impact of a pollen diet on the bumblebee colony development. 4. This study reveals that diverse pollen diet does not necessary equate with good colony development and supports the importance of selecting floral resources by considering their nutrient contents for bee conservation management. [less ▲]

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See detailSodium vanadium (III) fluorophosphate/carbon nanotubes composite (NVPF/CNT) prepared by spray-drying: good electrochemical performance thanks to well-dispersed CNT network within NVPF particles
Eshraghi, Nicolas ULg; Caes, Sebastien; Mahmoud, Abdelfattah ULg et al

in Electrochimica Acta (2017), 228

We successfully prepared NASICON-type Na3V2(PO4)2F3 (NVPF) and a Na3V2(PO4)2F3/carbon nanotubes (CNT) composite by spray-drying followed by heat treatment in argon for 2 hours at 600 °C. The addition of ... [more ▼]

We successfully prepared NASICON-type Na3V2(PO4)2F3 (NVPF) and a Na3V2(PO4)2F3/carbon nanotubes (CNT) composite by spray-drying followed by heat treatment in argon for 2 hours at 600 °C. The addition of CNT in the spray-drying solution creates a CNT network within the NVPF particles. After grinding, the smaller NVPF particles remain linked by CNT. Thanks to this conducting network, the composite powder displays competitive electrochemical performance when cycled against lithium in hybrid-ion batteries (2–4.6 V vs. Li+/Li) with specific capacities of 125 mAh.g−1 at C/10, 103 mAh.g−1 at 1C and 91 mAh.g−1 at 4C, together with 97.5% capacity retention at 1C over 100 cycles with coulombic efficiency of 99.4%. These results demonstrate that sodium vanadium (III) fluorophosphate electrode material can be obtained in a time-efficient way using the easily up-scalable spray-drying method. [less ▲]

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See detailImpact of Serious Games on Health and Well-being of Elderly: A Systematic Review
Nguyen, Thi Thanh Hai; Ishmatova, Diana; Tapanainen, Tommi ULg et al

in Proceedings of the 50th Hawaiian International Conference on Systems Sciences (2017, January 06)

Besides their entertainment value, serious games can have beneficial therapeutic effects for elderly people that improve their health and well-being. Games are likely to be accepted by elderly persons who ... [more ▼]

Besides their entertainment value, serious games can have beneficial therapeutic effects for elderly people that improve their health and well-being. Games are likely to be accepted by elderly persons who have enjoyed games their lives, and because there are more and more of such elderly, it is important to investigate games as a therapeutic device. This research reviewed the literature focusing on the effects of games on elderly persons in three main types of effects: physical, cognitive, and social effects. The majority of reviewed papers focused on physical and cognitive effects, and were published in recent years, which emphasizes the relative novelty of this topic and suggests that future research will need to address social impact as well. In addition, while many papers claimed positive impacts as a result of using games, our review found that more attention should be given to research designs. [less ▲]

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See detailA Framework for the Evaluation of Biosecurity, Commercial, Regulatory, and Scientific Impacts of Plant Viruses and Viroids Identified by NGS Technologies
Massart, Sebastien; Candresse, Thierry; Gil, Jose et al

in Frontiers in Microbiology (2017), 8(45),

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See detailPatterns of body size and shape diversification in marine angelfishes (Pomacanthidae)
Frederich, Bruno ULg; Santini, Francesco; Konow, Nicolai et al

Conference (2017, January 06)

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See detailStromal Modulators of TGF-β in Cancer
Costanza, Brunella ULg; Umelo, Ijeoma ULg; Bellier, Justine ULg et al

in Journal of clinical Medicine (2017)

Transforming growth factor-β (TGF-β) is an intriguing cytokine exhibiting dual activities in malignant disease. It is an important mediator of cancer invasion, metastasis and angiogenesis, on the one hand ... [more ▼]

Transforming growth factor-β (TGF-β) is an intriguing cytokine exhibiting dual activities in malignant disease. It is an important mediator of cancer invasion, metastasis and angiogenesis, on the one hand, while it exhibits anti-tumor functions on the other hand. Elucidating the precise role of TGF-β in malignant development and progression requires a better understanding of the molecular mechanisms involved in its tumor suppressor to tumor promoter switch. One important aspect of TGF-β function is its interaction with proteins within the tumor microenvironment. Several stromal proteins have the natural ability to interact and modulate TGF-β function. Understanding the complex interplay between the TGF-β signaling network and these stromal proteins may provide greater insight into the development of novel therapeutic strategies that target the TGF-β axis. The present review highlights our present understanding of how stroma modulates TGF-β activity in human cancers [less ▲]

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See detailCompte rendu de Lavocat (Françoise), Fait et fiction, Paris, Seuil, "Poétique", 2016, 618p.
Huppe, Justine ULg

in COnTEXTES : Revue de Sociologie de la Littérature (2017)

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See detailImage quality in Coronary CT Angiography: Challenges and technical solutions.
Ghekiere, Olivier; Salgado, Rodrigo; Buls, Nico et al

in British Journal of Radiology (2017)

Multidetector CT angiography has become a widely accepted examination for non-invasive evaluation of the heart and coronary arteries. Despite its ongoing success and worldwide clinical implementation, it ... [more ▼]

Multidetector CT angiography has become a widely accepted examination for non-invasive evaluation of the heart and coronary arteries. Despite its ongoing success and worldwide clinical implementation, it remains an often-challenging procedure in which image quality, and hence diagnostic value, is determined by both technical and patient-related factors. Thorough knowledge of these factors is important to obtain high quality examinations. In this review, we discuss several key elements that may adversely affect coronary CT angiography image quality as well as potential measures that can be taken to mitigate their impact. In addition, several recent vendor-specific advances and future directions to improve image quality are discussed. [less ▲]

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See detailLes batteries vont bouleverser notre quotidien
Scharff, Christine; Ernst, Damien ULg

Article for general public (2017)

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See detailSegregation and pattern formation in dilute granular media under microgravity conditions
Opsomer, Eric ULg; Noirhomme, Martial ULg; Vandewalle, Nicolas ULg et al

in NPJ Microgravity (2017), 3

Space exploration and exploitation face a major challenge: the handling of granular materials in low-gravity environments. Indeed, grains behave quite differently in space than on Earth, and the ... [more ▼]

Space exploration and exploitation face a major challenge: the handling of granular materials in low-gravity environments. Indeed, grains behave quite differently in space than on Earth, and the dissipative nature of the collisions between solid particles leads to clustering. Within poly-disperse materials, the question of segregation is highly relevant but has not been addressed so far in microgravity. From parabolic flight experiments on dilute binary granular media, we show that clustering can trigger a segregation mechanism, and we observe, for the first time, the formation of layered structures in the bulk. [less ▲]

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See detailLe chez soi des animaux
Despret, Vinciane ULg

Book published by actes sud (2017)

Le livre raconte aux enfants des histoires sur le rapport des animaux à leur habitat et à leur identité. Pour comprendre qu’au-delà des ressemblances et des différences, “ainsi va la vie sur cette terre ... [more ▼]

Le livre raconte aux enfants des histoires sur le rapport des animaux à leur habitat et à leur identité. Pour comprendre qu’au-delà des ressemblances et des différences, “ainsi va la vie sur cette terre qui est, pour chacun et pour nous tous, notre chez-nous”. [less ▲]

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See detailOptimal measurement counting time and statistics in gamma spectrometry analysis: The time balance
Guembou Shouop, Cébastien Joel ULg; Penabei, Samafou; Ndontchueng Moyo, Maurice et al

Scientific conference (2017, January 04)

The optimal measurement counting time for gamma-ray spectrometry analysis using HPGe detectors was determined in our laboratory by comparing twelve hours measurement counting time at day and twelve hours ... [more ▼]

The optimal measurement counting time for gamma-ray spectrometry analysis using HPGe detectors was determined in our laboratory by comparing twelve hours measurement counting time at day and twelve hours measurement counting time at night. The day spectrum does not fully cover the night spectrum for the same sample. It is observed that the perturbation come to the sun-light. After several investigations became clearer: to remove all effects of radiation from outside (earth, the sun, and universe) our system, it is necessary to measure the background for 24, 48 or 72 hours. In the same way, the samples have to be measured for 24, 48 or 72 hours to be safe to be purified the measurement (equality of day and night measurement). It is also possible to not use the background of the winter in summer. Depend on to the energy of radionuclide we seek, it is clear that the most important steps of a gamma spectrometry measurement are the preparation of the sample and the calibration of the detector. [less ▲]

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See detailThe W. M. Keck Observatory infrared vortex coronagraph and a first image of HIP79124 B
Serabyn, Eugene; Huby, Elsa ULg; Matthews, Keith et al

in Astronomical Journal (The) (2017), 153(1), 43

An optical vortex coronagraph has been implemented within the NIRC2 camera on the Keck II telescope and used to carry out on-sky tests and observations. The development of this new L'-band observational ... [more ▼]

An optical vortex coronagraph has been implemented within the NIRC2 camera on the Keck II telescope and used to carry out on-sky tests and observations. The development of this new L'-band observational mode is described, and an initial demonstration of the new capability is presented: a resolved image of the low-mass companion to HIP79124, which had previously been detected by means of interferometry. With HIP79124 B at a projected separation of 186.5 mas, both the small inner working angle of the vortex coronagraph and the related imaging improvements were crucial in imaging this close companion directly. Due to higher Strehl ratios and more relaxed contrasts in L' band versus H band, this new coronagraphic capability will enable high-contrast small-angle observations of nearby young exoplanets and disks on a par with those of shorter-wavelength extreme adaptive optics coronagraphs. [less ▲]

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See detailCharacterization of the inner disk around HD 141569 A from Keck/NIRC2 L-band vortex coronagraphy
Mawet, Dimitri; Choquet, Élodie; Absil, Olivier ULg et al

in Astronomical Journal (The) (2017), 153(1), 44

HD 141569 A is a pre-main sequence B9.5 Ve star surrounded by a prominent and complex circumstellar disk, likely still in a transition stage from protoplanetary to debris disk phase. Here, we present a ... [more ▼]

HD 141569 A is a pre-main sequence B9.5 Ve star surrounded by a prominent and complex circumstellar disk, likely still in a transition stage from protoplanetary to debris disk phase. Here, we present a new image of the third inner disk component of HD 141569 A made in the L' band (3.8 micron) during the commissioning of the vector vortex coronagraph recently installed in the near-infrared imager and spectrograph NIRC2 behind the W.M. Keck Observatory Keck II adaptive optics system. We used reference point spread function subtraction, which reveals the innermost disk component from the inner working distance of $\simeq 23$ AU and up to $\simeq 70$ AU. The spatial scale of our detection roughly corresponds to the optical and near-infrared scattered light, thermal Q, N and 8.6 micron PAH emission reported earlier. We also see an outward progression in dust location from the L'-band to the H-band (VLT/SPHERE image) to the visible (HST/STIS image), likely indicative of dust blowout. The warm disk component is nested deep inside the two outer belts imaged by HST NICMOS in 1999 (respectively at 406 and 245 AU). We fit our new L'-band image and spectral energy distribution of HD 141569 A with the radiative transfer code MCFOST. Our best-fit models favor pure olivine grains, and are consistent with the composition of the outer belts. While our image shows a putative very-faint point-like clump or source embedded in the inner disk, we did not detect any true companion within the gap between the inner disk and the first outer ring, at a sensitivity of a few Jupiter masses. [less ▲]

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See detailOmbres de réalité
Choffray, Jean-Marie ULg

Book published by Amazon, Kindle Edition - Seconde édition (2017)

« Ombres de réalité » a pour objectif de partager avec vous nombre d’erreurs personnelles – factuelles et d’appréciation –, à la lumière de ce que d’autres ont eu l’élégance de nous transmettre. Le socle ... [more ▼]

« Ombres de réalité » a pour objectif de partager avec vous nombre d’erreurs personnelles – factuelles et d’appréciation –, à la lumière de ce que d’autres ont eu l’élégance de nous transmettre. Le socle de la réalité, lieu de convergence de ses ombres, et que décrit à merveille la comédie humaine, ne peut jamais être approché qu’au travers d’une recherche sincère et permanente. Apprendre à désapprendre résolument, apprendre à reconstruire patiemment, et apprendre à transmettre modestement, constituent le but ultime de la vie. Personnellement, je n’en vois pas d’autre aujourd’hui. Après une brève introduction, ou « Sortie de l’ombre », de courts chapitres couvrent un thème particulier, généralement à la lumière d’observations, d’expériences personnelles, ou de lectures qui m’ont touché. La sélection et l’ordre des sujets ne traduit aucun souci particulier, même si je ne crois plus beaucoup au hasard. Tous deux pourraient évoluer au fil des révisions que connaîtra ce texte dans les années à venir. Le choix actuel va de « Chacun pour soi » au « Secret du silence », en passant par « L’aventure à deux », « La foire aux illusions », « La tyrannie des marchés », « L’intérêt général », « Non ! merci », et « Une chance d’être ». Chaque thème peut être exploré isolément. A vous, donc, de constituer votre menu en fonction de votre curiosité et de votre appétit. [less ▲]

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