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See detailComparison between various methods for the evaluation of the fire resistance of concrete filled hollow steel columns
Fellah, Farid; Dotreppe, Jean-Claude ULg; Seridi, Ahcène et al

in Proceeding of the Romanian Academy. Series A, Mathematics, Physics, Technical Sciences, Information Science (2011), 12(4), 324-331

Hollow steel columns filled with bar-reinforced concrete are used extensively in the construction of high-rise buildings. Many research works devoted to the fire resistance of these profiles have been ... [more ▼]

Hollow steel columns filled with bar-reinforced concrete are used extensively in the construction of high-rise buildings. Many research works devoted to the fire resistance of these profiles have been performed in Europe and in North America. Though calculation methods are now proposed in codes, more practical tools are needed by the design engineers. It is not easy to develop such methods due to the large scatter of experimental results. In this article three methods based on quite different procedures are examined. Comparisons have been made between the results obtained by the three methods and test results. The potentialities of each method are examined, but also the domains in which they should be used with care, or even they should not be used. [less ▲]

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See detailComparison between VeinoPlus Sport and TENS on the recovery on young soccer players
God, Maxime; LE GOFF, Caroline ULg; Evrard, Frédéric et al

in European Journal of Sports Medicine (2015, September), 3(Suppl 1), 106

Introduction Every physical activity is tiresome for the body; muscles produce metabolites and lactic acid which limit its working ability. It is then necessary to efficiently and quickly recover after ... [more ▼]

Introduction Every physical activity is tiresome for the body; muscles produce metabolites and lactic acid which limit its working ability. It is then necessary to efficiently and quickly recover after the effort. In fact, a bad recovery could bring prejudice to the following performance and the athlete's physical state. Active recovery and balneotherapy together with new techniques such as cryotherapy and electro stimulation are upcoming tools to recover better. The goal of this study was to compare the impact of 2 types of electro stimulator : « VeinoPlus Sport » (VPS) and « TENS » on amateur soccer players after Yo-Yo-type effort. Material and methods In an identical context, each athlete (20 soccer players; average age 17,1 ± 0,79) benefited from VPS and TENS during 2 different treatment sessions after 2 Yo-Yo-type efforts. Four blood samples were taken (lactate, blood gases, ions, cardiac markers,...) and an explosiveness Myotest evaluation was conducted respectively before effort, just after effort, after recovery, and after the second effort. A questionnaire on the fatigue state was filled out by each athlete. For the statistical analysis, we used the Anova algorithm of the StatPlus system and a Scheffé test. Results All athletes have ran a greater distance in their second effort especially in the VPS group but differences were insignificant. The test lead to a significant variation of lactate, HCO3- ions and myoglobin. The study of other blood parameters and of the explosiveness parameters didn't show any significant variations. Nevertheless according to the subjective athlete's opinion the VPS group has noted less legs pain, less overall fatigue, less diminishment of strength and fitter than the TENS group between 12 and 24 hours after effort. Finally all athletes have said to like the use of a electro-stimulation recovery device better than their normal daily recovery techniques without expressing any preferences between VPS and TENS. Discussion - Conclusion This comparative study only shows minor differences, non significant, between the two devices. The two groups have ran the greatest distance during the second effort which suggests that the test wasn't tiresome despite biological signs of "fatigue". However on subjective criteria of recovery and well-being a slight preference was shown for the VPS device. The results should be taken into consideration in a other comparative study of the recovery devices with more tiresome effort. [less ▲]

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See detailA comparison between visual estimates and image analysis measurements to determine Septoria leaf blotch severity in winter wheat
El Jarroudi, Moussa ULg; Kouadio, Louis; Mackels, Christophe et al

in Plant Pathology (2015)

Methods to estimate disease severity vary in accuracy, reliability, ease of use and cost. Severity of Septoria leaf blotch (SLB, caused by Zymoseptoria graminicola) was estimated by four raters and by ... [more ▼]

Methods to estimate disease severity vary in accuracy, reliability, ease of use and cost. Severity of Septoria leaf blotch (SLB, caused by Zymoseptoria graminicola) was estimated by four raters and by image analysis (assumed actual values) on individual leaves of winter wheat in order to explore accuracy and reliability of estimates, and to ascertain whether there were any general characteristics of error. Specifically, (i) we determined the accuracy and reliability of visual assessments of SLB over the full range of severity from 0 to 100%, and we investigated (ii) whether certain 10% ranges in actual disease severity between 0 and 100% were more prone to estimation error compared with others, and (iii) whether leaf position affected accuracy within those ranges. Lin's concordance correlation analysis of all severities (0 to 100%) demonstrated that all raters had estimates close to the actual values (agreement: ρc = 0.92-0.99). However, agreement between actual SLB severities and estimates by raters was less good when compared over short 10% subdivisions within the 0-100% range (ρc = -0.12 to 0.99). Despite common rater imprecision at estimating low and high SLB severities, individual raters differed considerably in their accuracy over the short 10% subdivisions. There was no effect of leaf position on accuracy or precision of severity estimate on separate leaves (L1-L3). Pursuing efforts in understanding error in disease estimation should aid in improving the accuracy of assessments, making visual estimates of disease severity more useful for research and applied purposes. [less ▲]

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See detailComparison between wind speed observed at 100m height and wind speeds simulated by the WRF and MAR models
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg et al

Poster (2014, June 06)

In the context of FLEXIPAC project funded by "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology and Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the ... [more ▼]

In the context of FLEXIPAC project funded by "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology and Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the WRF regional model (v.3.4.) forced by ERA-Interim model. Our analysis shows that wind speeds at 100m height simulated by WRF are systematically overestimated compared to wind speeds extracted from wind productions of two wind farms. In order to identify this problem, four comparisons were performed in this contribution. Firstly, we compare WRF model with reanalysis based forcing model. Secondly, we compare two WRF simulations, where one of them has a more precise spatial resolution. Thirdly, we smooth WRF outputs in time (6-hr running mean) in order to study the accuracy of the 30-min variability generated by WRF model. Finally, we comp compare the WRF model with the MAR (v3.3.) regional model using the same forcing at its lateral boundaries. This last one seems to suggest that the MAR model better simulates wind speeds at 10m and at 100m than WRF model and then that wind speed underestimation by WRF is well linked to the WRF physics itself. [less ▲]

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See detailComparison by image processing of target supports of spray droplets
Degre, Aurore ULg; Mostade, Olivier; Huyghebaert, Bruno et al

in transaction of the American society of Agricultural engineers (2001), 44(2), 217-222

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See detailComparison low cost chemical sensors analytical instruments for odour monitoring in a municipal waste plant
Romain, Anne-Claude ULg; Molitor, Noémie ULg; Adam, Gilles et al

in Chemical Engineering Transactions (2016), 54

The gas sensing performances of low cost commercial chemical sensors are compared to the ones of standardized chemical analysers. Real time measurements are performed on the field of three municipal solid ... [more ▼]

The gas sensing performances of low cost commercial chemical sensors are compared to the ones of standardized chemical analysers. Real time measurements are performed on the field of three municipal solid waste plants (MSW). Long-term campaigns of several months have been organised during the period 2010-2015. The sensors and the reference analysers have worked simultaneously. The selected sensors are commercial metal oxide semiconductor gas sensors (MOx, Figaro). The sensors-array devices are developed at the ULg laboratory (SAM). Analysers are certified and operated by the official Wallonia public scientific institute (ISSeP). In addition to odour, other target compounds are considered: methane, ammonia, hydrogen sulfide, but also NMHC as limonene, pinene and BTEX The laboratory has a long experience in using chemical sensors for odour in-field measurements, especially for landfills and composting plants. The aim of this study is to evaluate the performances of chemo-resistors array for continuous monitoring of compounds typical of municipal wastes in comparison to reference analysers. It highlights weaknesses and strengths of the two kinds of devices. The obtained results are considered for odour event detection as well as for chemical compound quantification and are discussed to evaluate the efficiency of metal oxide sensors for a low cost gas emissions assessment. [less ▲]

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See detailComparison of bronchodilators in feline airways: In vitro and in vivo investigations
Leemans, Jérôme ULg; Kirschvink, Nathalie; Delvaux, F. et al

in In proceedings: 15th Congress European College of Veterinary Internal Medicine – companion animals (2005)

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See detailComparison of hydrodynamic parameters obtained by 2D measurements in a flat rectangular column with X-ray radiography and data from literature on 3D columns
Calvo, Sébastien ULg; Beugre, Djomice Antoine ULg; Crine, Michel ULg et al

Poster (2010)

Hydrodynamic tests are performed in a flat rectangular column packed with two sheets of Mellapak 250 Y (Sulzer structured packing). Measurements are realized with a single phase liquid flow as well as ... [more ▼]

Hydrodynamic tests are performed in a flat rectangular column packed with two sheets of Mellapak 250 Y (Sulzer structured packing). Measurements are realized with a single phase liquid flow as well as with a gas-liquid counter-current flow. Hydrodynamic parameters are compared to experimental results obtained in 3D columns found in the literature, as well as to literature model predictions and to values computed using an in-house Lattice Boltzmann CFD simulation code. [less ▲]

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See detailComparison of 125I and 3H testosterone radioimmunoassay methods in bovine serum
Miklos, M.; Renaville, Robert ULg; Tözser, J.

in Klin Kiserl Lab Med (1994), 22

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See detailComparison of 15N labelled forages and 15N incorporation into microbe for microbial estimation in nylon bag residues : influence on the effective N degradability.
Kamoun, Mohammed; Beckers, Yves ULg; Thewis, André ULg et al

in Giesecke, D. (Ed.) Proceedings of the Society of Nutrition Physiology (1994, September)

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See detailA Comparison of 2 Mitral Annuloplasty Rings for Severe Ischemic Mitral Regurgitation: Clinical and Echocardiographic Outcomes.
Fattouch, Khalil; Moscarelli, Marco; Castrovinci, Sebastiano et al

in Seminars in Thoracic and Cardiovascular Surgery (2016), 28(2), 261-268

Controversies regarding the choice of annuloplasty rings for treatment of ischemic mitral regurgitation still exist. Aim of the study is to compare early performance of 2 different rings in terms of rest ... [more ▼]

Controversies regarding the choice of annuloplasty rings for treatment of ischemic mitral regurgitation still exist. Aim of the study is to compare early performance of 2 different rings in terms of rest and exercise echocardiographic parameters (transmitral gradient, systolic pulmonary artery pressure, and mitral valve area), clinical outcomes, and recurrence of mitral regurgitation. From January 2008 till December 2013, prospectively collected data of patients who underwent coronary artery bypass grafting and undersizing mitral valve annuloplasty for severe chronic ischemic mitral regurgitation at our Institution were reviewed. A total of 93 patients were identified; among them 44 had semirigid Memo 3D ring implanted (group A) whereas 49 had a rigid profile 3D ring (group B). At 6 months, recurrent ischemic mitral regurgitation, equal or more than moderate, was observed in 4 and 6 patients in the group A and B, respectively (P = 0.74). Group A showed certain improved valve geometric parameters such as posterior leaflet angle, tenting area, and coaptation depth. Transmitral gradient was significantly higher at rest in the group B (P < 0.0001). During exercise, significant increase of transmitral gradient and systolic pulmonary artery pressure was observed in group B (P < 0.0001). Mitral valve area was not statistically significantly smaller at rest in between groups (P = 0.09); however, it significantly decreased with exercise in group B (P = 0.01). At midterm follow-up, patients in group B were more symptomatic. In patients with chronic ischemic mitral regurgitation, use of semirigid Memo 3D ring when compared to the rigid Profile 3D may be associated with early improved mitral valve geometrical conformation and hemodynamic profile, particularly during exercise. No difference was observed between both groups in recurrent mitral regurgitation. [less ▲]

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See detailComparison of 2D turbulence models for steady flows computation in a macro-rough channel
Erpicum, Sébastien ULg; Meile, Tobias; Dewals, Benjamin ULg et al

in 2nd International Symposium on Shallow Flows (2008, December 11)

A 2D numerical flow model, developed at the Laboratory of Hydrology, Applied Hydrodynamics and Hydraulic Constructions (HACH) at ULg, has been applied to flows in a macro-rough channel using three ... [more ▼]

A 2D numerical flow model, developed at the Laboratory of Hydrology, Applied Hydrodynamics and Hydraulic Constructions (HACH) at ULg, has been applied to flows in a macro-rough channel using three different approaches to compute the turbulence effects. Both the first and second ones are based on algebraic expressions of the turbulent viscosity, and the third one uses a depth-integrated k- type model involving two additional partial differential equations. Data for the comparison have been provided by experiments conducted at the Laboratory of Hydraulic Constructions (LCH) at EPFL, showing different two-dimensional flow characteristics in varied configurations of large scale cavities in depressions at the side walls of the flume. Despite the strongly different modeling approaches used in the three models to handle the turbulence effects, the numerical models give generally similar and satisfactory agreement between experimental and numerical results regarding backwater curves. [less ▲]

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See detailComparison of 3 different variable selection strategies to improve the predictions of fatty acid profile in bovine milk by mid-infrared spectrometry
Soyeurt, Hélène ULg; Brostaux, Yves ULg; Dehareng, Frédéric et al

in Journal of Dairy Science (2015), 98(suppl 2), 804

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See detailComparison of 3 Diffractive IOLs in 3 Wavelengths Bifocal/ EDOF/Trifocal.
Gatinel, Damien; Pagnoulle, Christophe; Loicq, Jerôme ULg et al

Conference (2016, May)

Purpose To describe the optical performances of 3 types of diffractive hydrophobic intraocular lenses (IOLs): monofocal achromatic, bifocal and trifocal, using various visible wavelengths. Methods 3 IOLs ... [more ▼]

Purpose To describe the optical performances of 3 types of diffractive hydrophobic intraocular lenses (IOLs): monofocal achromatic, bifocal and trifocal, using various visible wavelengths. Methods 3 IOLs were measured with an optical bench (PMTF,LambdaX,Nivelles, Belgium) to determine modulation transfer function (MTF) and point spread function (PSF). Measurements were performed at 480 nm,546 nm,650 nm using an aberration free cornea and aspheric artificial cornea generating +0.28µm positive spherical aberration by ISO11979-2 guidelines. Through-focus MTF was recorded for various pupil apertures. Evaluation of halos was performed from PSF measurements obtained at each focal spot location. Images of USAF targets were recorded with simulated distances from 1m to 25cm. Amplitude of off-axis peaks of radial profile of PSF enabled to quantify percentage of energy within the halos. Results The monofocal and the bifocal IOLs presented 2 peaks on the through-focus MTF in green light: intermediate vision (at +1.75D) for the monofocal achromatic lens, and far and near vision (at +4D) for the bifocal IOL of the same material. Three peaks (Distance, Intermediate at +1.75D, Near at +3.5D) were recorded with the trifocal IOL at any wavelength. The achromatic monofocal IOL was monofocal for far vision with red light and monofocal for near vision with blue light. The influence of the cornea models was limited. The amount of halos were comparable between lenses (3 to 5 % of the enclosed central light energy). Conclusion The achromatic diffractive IOL behaved like a bifocal IOL with an intermediate addition foci in green light. The bifocal and trifocal IOL induced similar chromatic effects for the near (bifocal, trifocal) and intermediate (trifocal) foci. [less ▲]

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See detailComparison of 3 diffractive IOLs: one monofocal (achromatic), one bifocal and one trifocal lens implant
Gatinel, Damien; Loicq, Jerôme ULg; Pagnoule, Christophe et al

Conference (2015, September 08)

Purpose: To describe the optical performance of 3 types (monofocal, bifocal and trifocal) of diffractive hydrophobic intraocular lenses (IOLs). Setting: Fondation Rothschild, Paris, France Methods: An ... [more ▼]

Purpose: To describe the optical performance of 3 types (monofocal, bifocal and trifocal) of diffractive hydrophobic intraocular lenses (IOLs). Setting: Fondation Rothschild, Paris, France Methods: An achromatic monofocal, a bifocal and trifocal diffractive IOLs were measured with an optical bench, designed to measure Modulation transfer function (MTF) and point spread function (PSF) of diffractive intraocular lenses. The measurements were performed at 3 wavelengths (480 nm, 546 nm and 650 nm), using an aberration free cornea and an aspherical artificial cornea generating a +0.28 µm of positive spherical aberration (ISO 11979-2 guideline). The through-focus MTF was recorded with the 3 IOLs for various pupil apertures. The evaluation of the magnitude of the halos was performed from PSF measurement obtained at each focal spot location. Results: The monofocal and the two bifocal IOLs were presenting 2 peaks on the through-focus MTF in the green: for intermediate vision (at 1.75D) for the monofocal achromatic lens, and for far and for near vision( at +4D) for the bifocal IOL of the same material. Three peaks were recorded with the trifocal IOL at any wavelength. The achromatic monofocal was monofocal for far in the red and monofocal for near in the blue. The amount of energy allocated to each focal point was not very different for the three IOLs except for smaller apertures where the distance vision with the trifocal IOL had a significant lower peak than the two other IOLs. The amount of halos were comparable between lenses. Conclusions: The diffractive and refractive optics generated opposite chromatic aberration. A achromatic diffractive IOL behaves like a bifocal IOL with an intermediate addition The bifocal and trifocal IOL induce similar chromatic effects for the near (bifocal, trifocal) and intermediate (trifocal) foci. The tested diffractive patterns wee not efficient to correct the chromatic aberration at the distance foci for all tested IOLs. [less ▲]

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See detailComparison of 3 emerging optical NDI techniques on complex shaped composite structures based on carbon fiber
Georges, Marc ULg

Conference (2013, October 01)

Thermography, shearography and laser ultrasonics are 3 contactless emerging techniques which allow nondestructive inspection of composite structures. Thermography and shearography are full-field ... [more ▼]

Thermography, shearography and laser ultrasonics are 3 contactless emerging techniques which allow nondestructive inspection of composite structures. Thermography and shearography are full-field techniques yielding measurement of respectively local temperature variations or deformations of a structure undergoing a stress (thermal, pressure, vibration). Laser ultrasonics allows remote ultrasound generation in the composite by thermoelastic effect followed by remote measurement of the surface displacements under the effect of the ultrasound echoes without coupling. This point-like technique requires scanning. The three techniques have been selected in our project since they allow inspection of complex shaped parts. We present compared results obtained on a variety of aeronautical industrial composite parts. [less ▲]

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See detailA Comparison of 3D Methods for Identifying the Stance Phase in Treadmill Running for Both Rearfoot and Forefoot Runners
Deflandre, Dorian ULg; Schwartz, Cédric ULg; Weertz et al

in Journal of sports Science (2016), 4

We compared six 3D methods, OptoGait, and Myotest Run for the determination of contact time for runners with different foot strike patterns. Twenty male participants were divided into two groups: the heel ... [more ▼]

We compared six 3D methods, OptoGait, and Myotest Run for the determination of contact time for runners with different foot strike patterns. Twenty male participants were divided into two groups: the heel group, who attack the ground with the heel (n = 12), and the toe group, who attack the ground with the middle/front of the foot (n = 8). They performed trials at speeds of 8 km/h then 16 km/h. To detect foot strike, the use of peak velocity of 3D markers located on the heel, the fifth metatarsal, and the great toe provided the best results for both groups. To detect the toe off, the minimum vertical position of a 3D marker placed in line with the great toe gave the most satisfactory results for both groups. In this way, the values of contact time measured with the 3D methods are consistent. Values measured with OptoGait appear consistent too, while those of the Myotest Run underestimate the contact time for both speeds. 3D analysis provides interesting opportunities for calculation of contact time for both rearfoot and forefoot runners, using specific peak velocities to determine foot strike and marker displacement to determine toe off. [less ▲]

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