Accelerated oxidation test of freeze-dried Pseudomonas fluorescens BTP1, BB2 and PI9 strains.

in International Journal of Microbiology Research (2013)

Pseudomonas fluorescens strains are very susceptible to damage during freeze-drying and storage. It would be useful to have longer lasting viable powders. Membrane oxidation is one of the factors ... [more ▼]

Pseudomonas fluorescens strains are very susceptible to damage during freeze-drying and storage. It would be useful to have longer lasting viable powders. Membrane oxidation is one of the factors responsible for damages suffered by P. fluorescens strains during storage. Singlet oxygen (1O2) is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules. We exposed freeze-dried powders of three strains P. fluorescens (BB2, BTP1 and PI9) to singlet oxygen produced by photosensitisation of Methylene Blue/ light during 2 hours. We observe a significant loss in survival rate, a pronounced oxidation of polyunsaturated fatty acids, protein oxidation (carbonyl groups) and protein insolubilisation. This study enables better predictions of types of packaging suitable for freeze-dried powders of P. fluorescens. [less ▲]

Contribution à l'étude des amylases du sorgho et leurs utilisations dans la transformation des produits amylacés

Doctoral thesis (2013)

Les amylases sont des enzymes largement utilisées dans le secteur industriel. Elles occupent d'ailleurs une place primordiale dans le marché mondial des enzymes. Les travaux présentés dans ce manuscrit se ... [more ▼]

Les amylases sont des enzymes largement utilisées dans le secteur industriel. Elles occupent d'ailleurs une place primordiale dans le marché mondial des enzymes. Les travaux présentés dans ce manuscrit se sont intéressés à la production d’amylases à partir d’une source végétale peu coûteuse et disponible, le sorgho et aux possibilités de les utiliser dans la transformation des produits amylacés. Dans la première partie de l’étude, après avoir caractérisé et malté sept variétés de sorgho blanc sélectionné à l’ISRA de Bambey (Sénégal), la meilleure variété, la F-2-20 (sans tanins, faible teneur en composés phénoliques et bonnes activités amylasiques) a été retenue pour la suite de l’étude. Dans la deuxième partie des travaux, les paramètres physico-chimiques tels que le pH optimum, la température optimale et la thermostabilité des amylases (α et β) du malt ont été caractérisés. Les deux amylases ont le même pH optimal 5,5 et la température optimale est de 65 °C pour l’α-amylase et 55 °C pour la β amylase. Par ailleurs, le gène de la β-amylase a été aussi étudié. Les résultats de la troisième partie des travaux ont montré la capacité des amylases du malt de sorgho à être utilisées dans des processus d’hydrolyse d’amidon (maïs et blé) et farines (blé et manioc). L’ajout d’ions calcium n’améliore pas significativement les rendements d’hydrolyse. Enfin, suite aux résultats obtenus, l’hydrolyse a été réalisée à plus grande échelle afin de produire des dextrines de différents DE. Les dextrines ont été analysées chimiquement et physicochimiquement pour déterminer leur composition en oligosaccharides et leurs propriétés physiques en vue de leur application dans les secteurs agroalimentaires. [less ▲]

Demenz im Bilderbuch? Martin Baltscheits "Geschichte vom Fuchs der den Verstand verlor"

Article for general public (2013)

A NEW SIMPLIFIED ANALYTICAL DESIGN METHOD FOR STEEL AND COMPOSITE SWAY FRAMES

in Journal of Constructional Steel Research (2013)

Eurocode 4 is the European design code for composite construction; in its so-called EN 1994-1-1 version, the design of “non-sway buildings” is mainly covered. As a result, EC4 focuses on the check of ... [more ▼]

Eurocode 4 is the European design code for composite construction; in its so-called EN 1994-1-1 version, the design of “non-sway buildings” is mainly covered. As a result, EC4 focuses on the check of structural elements like beams, columns, slabs and joints. However, in the last years, the construction of taller buildings and larger industrial halls without wind bracing systems tends to make global instability a relevant failure mode, which is not well covered by Eurocode 4. Recently, intensive experimental, numerical and theoretical investigations have been carried out at Liège University. The latter aimed at improving the knowledge in the field of sway composite building frames and at developing appropriate design rules. The rotational behavior of the beam-to-column composite joints is one of the key aspects of the problem to which a special attention has been paid. This paper reflects investigations carried out at Liège University on this topic. In particular, an innovative simplified analytical method to predict the ultimate loading factor and the associated collapse mode of both steel and composite frames subjected to static loadings is presented. [less ▲]

Homo ludens en la Revolución. Una lectura de Nellie Campobello

Book published by Iberoamericana/Vervuert (2013)

Holographic interferometry based on photorefractive crystal to measure 3D thermo-elastic distortion of composite structures and comparison with finite element models

in Lehmann, Peter (Ed.) Proc. SPIE Vol 8788 on Optical Measurement Systems for Industrial Inspection VIII (2013, May)

Thermo-elastic distortions of composite structures have been measured by a holographic camera using a BSO photorefractive crystal as the recording medium. The first test campaign (Phase 1) was performed ... [more ▼]

Thermo-elastic distortions of composite structures have been measured by a holographic camera using a BSO photorefractive crystal as the recording medium. The first test campaign (Phase 1) was performed on CFRP struts with titanium end-fittings glued to the tips of the strut. The samples were placed in a vacuum chamber. The holographic camera was located outside the chamber and configured with two illuminations to measure the relative out-of-plane and in-plane (in one direction) displacements. The second test campaign (Phase 2) was performed on a structure composed of a large Silicon Carbide base plate supported by 3 GFRP struts with glued Titanium end-fittings. Thermo-elastic distortions have been measured with the same holographic camera used in phase 1, but four illuminations, instead of two, have been used to provide the three components of displacement. This technique was specially developed and validated during the phase 2 in CSL laboratory. The system has been designed to measure an object size of typically 250x250 mm²; the measurement range is such that the sum of the largest relative displacements in the three measurement directions is maximum 20 μm. The validation of the four-illuminations technique led to measurement uncertainties of 120 nm for the relative in-plane and out-of-plane displacements, 230 nm for the absolute in-plane displacement and 400 nm for the absolute out-of-plane displacement. For both campaigns, the test results have been compared to the predictions obtained by finite element analyses and the correlation of these results was good [less ▲]

Statistical analysis of modulated codes for robot positioning -- Application to BeAMS

Report (2013)

Positioning is a fundamental issue for mobile robots. Therefore, a performance analysis is suitable to determine the behavior of a system, and to optimize its working. Unfortunately, some systems are only ... [more ▼]

Positioning is a fundamental issue for mobile robots. Therefore, a performance analysis is suitable to determine the behavior of a system, and to optimize its working. Unfortunately, some systems are only evaluated experimentally, which makes the performance analysis and design decisions very unclear. In [4], we have proposed a new angle measurement system, named BeAMS, that is the key element of an algorithm for mobile robot positioning. BeAMS introduces a new mechanism to measure angles: it detects a beacon when it enters and leaves an angular window. A theoretical framework for a thorough performance analysis of BeAMS has been provided to establish the upper bound of the variance, and to validate this bound through experiments and simulations. It has been shown that the estimator derived from the center of this angular window provides an unbiased estimate of the beacon angle. This document complements our paper by going into further details related to the code statistics of modulated signals in general, with an emphasis on BeAMS. In particular, the probability density function of the measured angle has been previously established with the assumption that there is no correlation between the times a beacon enters the angular window or leaves it. This assumption is questionable and, in this document, we reconsider this assumption and establish the exact probability density function of the angle estimated by BeAMS (without this assumption). The conclusion of this study is that the real variance of the estimator provided by BeAMS was slightly underestimated in our previous work. In addition to this speci c result, we also provide a new and extensive theoretical approach that can be used to analyze the statistics of any angle measurement method with beacons whose signal has been modulated. To summarize, this technical document has four purposes: (1) to establish the exact probability density function of the angle estimator of BeAMS, (2) to calculate a practical upper bound of the variance of this estimator, which is of practical interest for calibration and tracking (see Table 1, on page 13, for a summary), (3) to present a new theoretical approach to evaluate the performance of systems that use modulated (coded) signals, and (4) to show how the variance evolves exactly as a function of the angular window (while re- maining below the upper bound). [less ▲]

Un travailleur peut-il renoncer aux droits issus de son contrat de travail ?

in Revue de la factulté de droit de l'Université de Liège (2013), 1

Lorsque seuls des intérêts particuliers sont en jeu, la renonciation à un droit acquis est licite après la cessation de la cause de la protection légale ; si la loi est d'ordre public, c'est-à-dire si l ... [more ▼]

Lorsque seuls des intérêts particuliers sont en jeu, la renonciation à un droit acquis est licite après la cessation de la cause de la protection légale ; si la loi est d'ordre public, c'est-à-dire si l'intérêt général est concerné, la renonciation est parfois autorisée et parfois prohibée, selon la disposition en jeu. [less ▲]

Entre recettes du Soi et recettes de l’Autre. Ethnographie de pratiques culinaires marocaines en Italie.

Scientific conference (2013, April 30)

Ma recherche concerne les processus de subjectivation de femmes migrantes marocaines à Milan à travers la culture matérielle. En particulier, mon étude intéresse les pratiques culinaires et les objets que ... [more ▼]

Ma recherche concerne les processus de subjectivation de femmes migrantes marocaines à Milan à travers la culture matérielle. En particulier, mon étude intéresse les pratiques culinaires et les objets que celles-ci impliquent et la façon dans laquelle elle déterminent précises construction du soi, en permettant l’adhésion à un savoir et un style dynamique et partagé. En outre, j’analyse le rapport entre ces processus et les discours locaux et globaux autour de la nourriture ethnique, lieu métaphorique de la rencontre avec l’altérité. [less ▲]

Le kimbanguisme aujourd’hui : une Église prophétique entre dispersion et centralité

Scientific conference (2013, April 30)

Dans mon exposé, je rends compte des mouvements disruptifs ou de dispersion qui animent l’imaginaire, c’est-à-dire les croyances partagées, et les pratiques de l’Église kimbanguiste (EJCSK) depuis les ... [more ▼]

Dans mon exposé, je rends compte des mouvements disruptifs ou de dispersion qui animent l’imaginaire, c’est-à-dire les croyances partagées, et les pratiques de l’Église kimbanguiste (EJCSK) depuis les années 1990. Il s’agit : premièrement, du surgissement de figures charismatiques en marge de l’Église (les Milimo), deuxièmement, de l’apparition d’une hétérodoxie doctrinale, et, troisièmement, de la dissidence à l’œuvre dans l’Église depuis 2002. Je montre que l’Église s’emploie à contenir son risque d’éclatement en multipliant les opérations de recentrages théologiques, institutionnels et charismatiques, voire politiques et cela jusqu’au sein de sa diaspora. [less ▲]