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See detailNon-Destructive Methods for the Detection of Delaminations in Concrete Bridge Decks
Van der Wielen, Audrey ULg

Master's dissertation (2009)

To detect delaminations in concrete bridge decks, the non-destructive techniques (NDT) permit a frequent inspection of the slabs without damaging the structures. Within this study, twelve samples were ... [more ▼]

To detect delaminations in concrete bridge decks, the non-destructive techniques (NDT) permit a frequent inspection of the slabs without damaging the structures. Within this study, twelve samples were realized, presenting diverse horizontal defects simulating delaminations. They were scanned with high frequency GPR with the common offset (CO) and common mid point (CMP) methods. The electromagnetic waves speed and defects depth were determined from the CMPs. A 3D visualization program was also created to display the CO measurements. The visibility of the inserted defects revealed to be dependent on their lateral extension, their thickness and especially their constitutive material. [less ▲]

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See detailNon-destructive provenance differentiation of prehistoric pigments by external PIXE
Beck, Lucile; Salomon, Hélène ULg; Lahlil, Sophia et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2012), 273

The elemental analysis of minerals/rocks has been often used for the determination of their geological origin. When these natural rocks were exploited by prehistoric civilizations as objects, weapons, or ... [more ▼]

The elemental analysis of minerals/rocks has been often used for the determination of their geological origin. When these natural rocks were exploited by prehistoric civilizations as objects, weapons, or pigments, the composition of the minerals can provide information on the mobility, the exchanges and the interaction between groups of population. In this paper, we will present results obtained from archaeological samples of prehistoric pigments, mainly iron and manganese oxides. PIXE analysis has been applied to samples of the prehistoric cave “La grotte du Renne” in previous termArcynext term-previous termsurnext term-previous termCurenext term, France (Chatelperronian, 38,000–34,000 BP). Because most of the archaeological objects are decorated or display some use marks, it is not possible to take samples. Consequently, we have used a non-destructive technique thanks to the external beam of AGLAE (C2RMF, Paris). In order to improve the limits of detection (LOD less than 10 ppm from Cu to Sb), a metal absorber has been placed on the X-ray detector to preferentially filter the Fe–K or Mn–K lines. Based on the quantitative analysis of major and trace elements, we have obtained groups of compositions corresponding to different geological sources. We demonstrate in this study that it is possible to extend PIXE analysis to the characterization of prehistoric pigments such as iron and manganese oxides for differentiating potential sources of pigments in archaeological contexts. [less ▲]

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See detailA non-destructive testing application solved with A-X geometric eddy-current formulation
Codecasa, Lorenzo; Dular, Patrick ULg; Specogna, Ruben et al

in COMPEL (2010), 29(6), 1606-1615

Purpose – The purpose of this paper is to introduce a perturbation method for the A-X geometric formulation to solve eddy-current problems and apply it to the feasibility design of a non-destructive ... [more ▼]

Purpose – The purpose of this paper is to introduce a perturbation method for the A-X geometric formulation to solve eddy-current problems and apply it to the feasibility design of a non-destructive evaluation device suitable to detect long-longitudinal volumetric flaws in hot steel bars. Design/methodology/approach – The effect of the flaw is accurately and efficiently computed by solving an eddy-current problem over an hexahedral grid which gives directly the perturbation due to the flaw with respect to the unperturbed configuration. Findings – The perturbation method, reducing the cancelation error, produces accurate results also for small variations between the solutions obtained in the perturbed and unperturbed configurations. This is especially required when the tool is used as a forward solver for an inverse problem. The method yields also to a considerable speedup: the mesh used in the perturbed problem can in fact be reduced at a small fraction of the initial mesh, considering only a limited region surrounding the flaw in which the mesh can be refined. Moreover, the full three-dimensional unperturbed problem does not need to be solved, since the source term for computing the perturbation is evaluated by solving a two-dimensional flawless configuration having revolution symmetry. Originality/value – A perturbation method for the A-X geometric formulation to solve eddy-current problems has been introduced. The advantages of the perturbation method for non-destructive testing applications have been described. [less ▲]

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See detailNon-dissipative joints in seismic resistant building frames - Bolted beam-to-column joints
Coméliau, Ludivine ULg; Demonceau, Jean-François ULg; Jaspart, Jean-Pierre ULg

in EUROSTEEL 2011 - 6th European Conference on Steel and Composite Structures - Proceedings (2011, September)

According to Eurocode 8, earthquake resistant steel building frames shall be designed following either the “low dissipative structural behaviour concept” or the “dissipative structural behaviour concept” ... [more ▼]

According to Eurocode 8, earthquake resistant steel building frames shall be designed following either the “low dissipative structural behaviour concept” or the “dissipative structural behaviour concept”. In the second concept, the capability of parts of the structure to resist earthquake actions through inelastic behaviour is taken into account: energy is dissipated in plastic mechanisms. In such a design, it has to be ensured that the dissipative zones form where they are intended to and that they yield before other zones leave the elastic range. In particular, moment resisting frames are designed in such a way that plastic hinges develop at the extremities of the beams. These dissipative zones can be located either in the beams or in the beam-to-column joints. In this paper, non-dissipative bolted beam-to-column connections are considered. They must be sufficiently resistant to remain in elastic range while cyclic yielding develops in the dissipative zones located in the beams. Besides, the possibility that the actual yield strength of the beam is higher than the nominal value has to be taken into account by a material overstrength factor. Such an approach generally leads to very strong and thus expensive joints. In the present paper, a design strategy leading to more economical solutions for full-strength beam-to-column joints is detailed. This study was conducted within the framework of an RFCS project called HSS-SERF (High Strength Steel in Seismic Resistant Building Frames). The considered moment-resisting joints are part of seismic resistant building frames made of high strength steel composite columns and mild carbon steel beams. The columns are either partially-encased wide-flange columns (H columns) or concrete-filled rectangular hollow-section columns (RHS columns). The proposed joint configuration uses hammer-heads extracted from the beam profile. To fulfil the resistance requirement taking account of the possible overstrength of the beam, the resistant moment of the joint is decomposed in the contributions of the different components involved. Then, no overstrength factor needs to be considered for the components related to the beam itself and to the hammer-heads. This approach is in full accordance with the basic principles of Eurocode 8 and can decrease much the required resistance of the joints provided some conditions are fulfilled, meaning lower costs. [less ▲]

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See detailLa non-expression de l’objet direct en égyptien ancien : études valentielles
Winand, Jean ULg

in Lingua Aegyptia [= LingAeg] (2004), (12), 205-234

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See detailNon-fluorescent, short-lived intermediate in photoenzymatic protochlorophyllide reduction at room temperature
Franck, Fabrice ULg; Dujardin, E.; Sironval, C.

in Plant Science Letters (1980), 18

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See detailNon-Gaussian behavior and anticorrelations in ultrathin gate oxides after soft breakdown
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg; Houssa, M. et al

in Applied Physics Letters (1999), 74(11), 1579-1581

The time dependence of the gate voltage V-G(t) after soft breakdown of metal-oxide-semiconductor capacitors with a 2.4 nm SiO2 layer has been measured. It is found that the V-G(t) fluctuation ... [more ▼]

The time dependence of the gate voltage V-G(t) after soft breakdown of metal-oxide-semiconductor capacitors with a 2.4 nm SiO2 layer has been measured. It is found that the V-G(t) fluctuation distributions are non-Gaussian, but can be described by a Levy stable distribution. The long-range correlations in V-G(t) are investigated within the detrended fluctuations analysis. The Hurst exponent is found to be H = 0.25 +/- 0.04 independent of the value of the stress current density J. It is argued that these are universal features of soft breakdown and are due to trapping-detrapping of electrons in and away from the primary percolation path. [less ▲]

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See detailNon-Gaussian electrical fluctuations in a quasi-2d packing of metallic beads
Vandewalle, Nicolas ULg; Lenaerts, Cedric ULg; Dorbolo, Stéphane ULg

in Europhysics Letters [=EPL] (2001), 53(2), 197-201

The electrical properties of a two-dimensional packing of metallic beads are studied. Small mechanical perturbations of the packing lead to giant voltage fluctuations. Fluctuations are found to be non ... [more ▼]

The electrical properties of a two-dimensional packing of metallic beads are studied. Small mechanical perturbations of the packing lead to giant voltage fluctuations. Fluctuations are found to be non-Gaussian and seem to belong to Levy stable distributions. Anticorrelations have been also found for the sign of these fluctuations. [less ▲]

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See detailNon-genetic factors affecting the reproduction performance, lamb growth and productivity indices of Djallonke sheep
Gbangboche, A. B.; Adamou-Ndiaye, M.; Youssao, A. K. I. et al

in Small Ruminant Research (2006), 64((1-2)), 133-142

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See detailNon-graphical solutions to Cattell's scree test
Raîche, Gilles; Walls, Ted; Magis, David ULg et al

in Methodology: European Journal of Research Methods for the Behavioral and Social Sciences (2013), 9

Most of the strategies that have been proposed to determine the number of components that account for the most variation in a principal components analysis of a correlation matrix rely on the analysis of ... [more ▼]

Most of the strategies that have been proposed to determine the number of components that account for the most variation in a principal components analysis of a correlation matrix rely on the analysis of the eigenvalues and on numerical solutions. The Cattell’s scree test is a graphical strategy with a nonnumerical solution to determine the number of components to retain. Like Kaiser’s rule, this test is one of the most frequently used strategies for determining the number of components to retain. However, the graphical nature of the scree test does not definitively establish the number of components to retain. To circumvent this issue, some numerical solutions are proposed, one in the spirit of Cattell’s work and dealing with the scree part of the eigenvalues plot, and one focusing on the elbow part of this plot. A simulation study compares the efficiency of these solutions to those of other previously proposed methods. Extensions to factor analysis are possible and may be particularly useful with many low-dimensional components. [less ▲]

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See detailNon-hypertrophic familial neuropathy associated with intention tremor. A variety of Charcot-Marie-Tooth disease?
Delwaide, P. J.; Schoenen, Jean ULg

in Journal of the Neurological Sciences (1976), 27(1), 59-69

A family with an association of sensorimotor neuropathy and intention tremor is reported. Clinical examination of 3 affected family members showed in varying degrees areflexia, muscle wasting, impairment ... [more ▼]

A family with an association of sensorimotor neuropathy and intention tremor is reported. Clinical examination of 3 affected family members showed in varying degrees areflexia, muscle wasting, impairment of deep sensation with an ataxic gait, pes cavus and disabling intention tremor. Motor nerve conduction velocities were moderately slowed. A superficial peroneal nerve biopsy showed axonal degeneration without segmental demyelination or onion bulb formation. Our observation seems to indicate an association of intention tremor with the non-hypertrophic variety of Charcot-Marie-Tooth disease. It can therefore be suggested that the two classical types of Charcot-Marie-Tooth syndrome possess variants which are associated with intention tremor. This association is well-known for the hypertrophic type; our report gives an example of the non-hypertrophic type. [less ▲]

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See detailNon-industrial seeds as a civic entry point to sustainable food systems
Hecquet, Corentin ULg

in XXV Congres ESRS (2013, August)

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See detailNon-industrial seeds in search of qualification
Hecquet, Corentin ULg

Conference (2013, May 23)

The aim of this paper is to summarize the current state of knowledge about non-industrial seed production in order to refine my research question. The idea is to understand how and on what foundations ... [more ▼]

The aim of this paper is to summarize the current state of knowledge about non-industrial seed production in order to refine my research question. The idea is to understand how and on what foundations equivalences between seeds and are established and to compare this with the same processes for industrially produced seeds. I shall end by presenting some empirical cases that will enable me to cover my question. [less ▲]

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See detailNon-infusional vs intravenous consolidation chemotherapy in eldery patients with acute myeloid leukemia : final results of th EORTC-GIMAMA AML-13 randomized phase III trial
Jehn, U.; Suciu, S.; Thomas, X. et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (2006), 20

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See detailNon-innocent Behaviour of Dithiocarboxylate Ligands Based on N-Heterocyclic Carbenes
Naeem, Saira; Thompson, Amber L.; Delaude, Lionel ULg et al

in Chemistry : A European Journal (2010), 16(36), 10971-10974

The ruthenium(II) complex [Ru(CH=CHC6H4Me-4)(κ2-S2C•NHC)(CO)(PPh3)2]+ is formed on reaction of NHC•CS2 (NHC = ICy, IMes) with [Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] in the presence of NH4PF6, whereas the ... [more ▼]

The ruthenium(II) complex [Ru(CH=CHC6H4Me-4)(κ2-S2C•NHC)(CO)(PPh3)2]+ is formed on reaction of NHC•CS2 (NHC = ICy, IMes) with [Ru(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] in the presence of NH4PF6, whereas the analogous reaction with the more bulky IDip•CS2 leads to the remarkable product, [Ru{κ2-SC(H)S(CH=CHC6H4Me-4)•IDip}Cl(CO)(PPh3)2]+. [less ▲]

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See detailNon-insulin-dependent diabetes mellitus in the elderly.
Scheen, André ULg

in Bailliere's Clinical Endocrinology and Metabolism (1997), 11(2), 389-406

The prevalence of non-insulin-dependent diabetes mellitus dramatically increases with age. Older diabetic subjects have an increased frequency of complications from diabetes compared with their younger ... [more ▼]

The prevalence of non-insulin-dependent diabetes mellitus dramatically increases with age. Older diabetic subjects have an increased frequency of complications from diabetes compared with their younger counterparts and higher morbidity and mortality rates compared with age-matched non-diabetic controls. Elderly patients with diabetes are generally treated following the same approach as in younger patients: dietary therapy first, followed by oral hypoglycaemic agents and ultimately insulin. However, several specificities should be pointed out. Changes associated with ageing may affect the pharmacokinetics and pharmacodynamics of both sulphonylureas (increasing the risk of severe hypoglycaemia) and biguanides (increasing the risk of lactic acidosis). The best insulin regimen in old age is not known, but a twice-daily injection of a pre-mixed insulin preparation is usually recommended. Goals of therapy must be realistic and not cause disabling side-effects. The general practitioner plays a crucial role in the care of elderly diabetic patients, but access to a multidisciplinary specialized team may be necessary. [less ▲]

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See detailA non-invasive approach to study lifetime exposure and bioaccumulation of PCBs in protected marine mammals: PBPK modeling in harbor porpoises
Weijs, Liesbeth; Covaci, Adrian; Yang, Raymond S. H. et al

in Toxicology and Applied Pharmacology (2011), In Press, Corrected Proof

In the last decade, physiologically based pharmacokinetic (PBPK) models have increasingly been developed to explain the kinetics of environmental pollutants in wildlife. For marine mammals specifically ... [more ▼]

In the last decade, physiologically based pharmacokinetic (PBPK) models have increasingly been developed to explain the kinetics of environmental pollutants in wildlife. For marine mammals specifically, these models provide a new, non-destructive tool that enables the integration of biomonitoring activities and in vitro studies. The goals of the present study were firstly to develop PBPK models for several environmental relevant PCB congeners in harbor porpoises (Phocoena phocoena), a species that is sensitive to pollution because of its limited metabolic capacity for pollutant transformation. These models were tested using tissue data of porpoises from the Black Sea. Secondly, the predictive power of the models was investigated for time trends in the PCB concentrations in North Sea harbor porpoises between 1990 and 2008. Thirdly, attempts were made to assess metabolic capacities of harbor porpoises for the investigated PCBs. In general, results show that parameter values from other species (rodents, humans) are not always suitable in marine mammal models, most probably due to differences in physiology and exposure. The PCB 149 levels decrease the fastest in male harbor porpoises from the North Sea in a time period of 18†years, whereas the PCB 101 levels decrease the slowest. According to the models, metabolic breakdown of PCB 118 is probably of lesser importance compared to other elimination pathways. For PCB 101 and 149 however, the presence of their metabolites can be attributed to bioaccumulation of metabolites from the prey and to metabolic breakdown of the parent compounds in the harbor porpoises. [less ▲]

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See detailNon-invasive assessment of airway responsiveness in healthy and allergen-sensitised cats by use of barometric whole body plethysmography
Kirschvink, N.; Leemans, Jérôme ULg; Delvaux, François et al

in Veterinary Journal (2007), 173(2), 343-352

This study aimed at determining whether airway responsiveness (AR) tests performed by use of barometric whole body plethysmography (BWBP) were repeatable in cats and to what extent AR was affected by the ... [more ▼]

This study aimed at determining whether airway responsiveness (AR) tests performed by use of barometric whole body plethysmography (BWBP) were repeatable in cats and to what extent AR was affected by the nebulization protocol used, the age of the animals, the inflammatory status of the airways and prior bronchodilator treatment. Repeatability of AR was tested on two occasions in 30 healthy cats. The concentration of carbachol inducing a 300% increase of the enhanced pause (Penh) - an estimator of airflow limitation - was calculated (C-Penh300) and did not differ significantly between the two tests (0.035 +/- 0.017% compared to 0.034 +/- 0.016%) and was significantly and positively correlated. The comparison between rapidly and slowly increasing carbachol concentrations was performed in ten healthy cats and showed a significantly lower C-Penh300 (%) when slowly increasing concentrations were used (0.037 +/- 0.013% compared to 0.039 +/- 10.015%, P < 0.05). A significant age-related increase of C-Penh300 was evidenced by performing AR tests in 15 healthy cats at 12, 18, 24 and 30 months (12 months: 0.026 +/- 0.008%, 18 months: 0.031 +/- 0.009%, 24 months: 0.038 +/- 0.01%, 30 months: 0.043 +/- 0.014%, P < 0.05). C-Penh300 significantly decreased in 12 Ascaris suum-sensitised cats after allergen exposure (0.026 +/- 0.016% compared to 0.033 +/- 0.016%, P < 0.05) and was negatively correlated with the granulocyte percentage of bronchoalveolar lavage fluid (r = -0.36, P < 0.01). Compared with a placebo inhalation, pretreatment with inhaled salbutamol significantly increased C-Penh300 in four healthy cats (0.093 +/- 0.021% compared to 0.036 +/- 0.004%, P < 0.05). This study provides evidence that AR determination by use of BWBP is promising as non-invasive indicator of lower airway inflammation or for monitoring response to bronchodilator treatment. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailNon-invasive assessment of arterial haemoglobin oxygen saturation in cattle by pulse oximetry
Coghe, Joost; Uystepruyst, Christophe; Bureau, Fabrice ULg et al

in Veterinary Record : Journal of the British Veterinary Association (1999), 145

The aim of this study was to evaluate the practicality and accuracy of different attachment sites for the optodes of a pulse oximeter (measuring arterial haemoglobin oxygen saturation) in healthy cattle ... [more ▼]

The aim of this study was to evaluate the practicality and accuracy of different attachment sites for the optodes of a pulse oximeter (measuring arterial haemoglobin oxygen saturation) in healthy cattle, and to assess the accuracy of pulse oximetry in diseased cattle with low haemoglobin oxygen saturation values caused by respiratory disease. The tait the nasal septum and the genital mucosa of females provided a continuous, stable and intense signal. The smallest bias, and no significant difference between measurements of arterial haemoglobin (mSp02) with the pulse oximeter and measurements of arterial haemoglobin oxygen saturation (SaOZ) with a blood gas analyser was obtained when the probe was attached to the tail. This site was used to evaluate the accuracy of pulse oximetry in animais with respiratory disease. There was a small bias between the measurements of Sa02 and mSp02, with a tendency for pulse oximetry to underestimate higher values and to overestimate lower values. The precision of pulse oximetry decreased substantially with the values for Sa02 <80 per cent, which lies outside the clinically relevant range [less ▲]

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See detailNon-invasive assessment of growth, gender and time of day related changes of respiratory pattern in healthy cats by use of barometric whole body plethysmography.
Kirschvink, Nathalie; Leemans, Jérôme ULg; Delvaux, François ULg et al

in Veterinary Journal (2006), 172(3), 446-454

The objective of this study was to establish a reference base for respiratory variables (respiratory rate [R(R)], inspiratory and expiratory time [T(i) and T(e)], peak inspiratory and expiratory ... [more ▼]

The objective of this study was to establish a reference base for respiratory variables (respiratory rate [R(R)], inspiratory and expiratory time [T(i) and T(e)], peak inspiratory and expiratory pseudoflow [PIF and PEF], tidal volume [V(T)], minute ventilation [V(E)] and enhanced pause [Penh]) of healthy cats by use of barometric whole body plethysmography (BWBP). Eighteen healthy European cats (10 male, 8 female) were studied from the age of 3 to 13 months in order to assess growth- and gender-related changes of BWBP variables. Chest radiographs and bronchoalveolar lavage cytology were performed to confirm pulmonary health status. Diurnal changes were investigated every 2 h over a period of 24 h when the cats were adult. V(T), V(E), PIF and PEF significantly increased during somatic growth and were higher in males than in females, whereas R(R), T(i), T(e), T(e)/T(i) ratio, PEF/PIF ratio and Penh remained unchanged and were not affected by gender. When measured over 24 h, Penh, T(e) and T(i) were significantly increased in the early morning hours (04:00 h), whereas R(R), PIF and PEF were decreased at that time. This study provides reference values of BWBP variables for healthy male and female cats and indicates when circadian changes might be observed [less ▲]

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