References of "Denoël, Vincent"
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See detailPlatelet-rich plasma (PRP) and tendon healing: comparison between fresh and frozen-thawed PRP
KAUX, Jean-François ULiege; Libertiaux, Vincent; Dupont, Laura ULiege et al

in Platelets (in press)

Platelet-rich plasma (PRP) is increasingly used in the treatment of musculoskeletal diseases. Its preservation by freezing it for the realization of multiple injections in clinical use has never been ... [more ▼]

Platelet-rich plasma (PRP) is increasingly used in the treatment of musculoskeletal diseases. Its preservation by freezing it for the realization of multiple injections in clinical use has never been discussed. Calcaneal tendons of rats were surgically sectioned. Platelet concentration of the PRP was 2.5 x 106/μl with autologous plasma of rats. Frozen-thawed PRP was prepared by performing two cycles of freezing and thawing on PRP aliquots. Both platelet preparations were injected in the lesion. Biomechanical and histological evaluations were carried out after 7, 20 or 40 days post surgery. After 7 and 40 days, no significant difference was observed between the PRP and the frozen-thawed PRP group. There is however a difference 20 days after surgery: the ultimate tensile strength (UTS) was greater in the fresh PRP group. No obvious difference with histological aspect was observed between the two groups. In conclusion, fresh PRP and frozen-thawed PRP injections can lead to similar results in the healing process of section calcaneal tendons of rats. Improvements with fresh PRP are slight. PRP could thus be frozen to be preserved if multiple injections are needed (e.g. osteoarthritis). [less ▲]

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See detailA low-order analytical model to monitor tension in shallow cables with specific end conditions
Geuzaine, Margaux ULiege; Denoël, Vincent ULiege

Poster (2019, March 15)

In order to remotely monitor tension in a cable over time, an appropriate method is based on the natural frequencies of the cable measured by means of wireless accelerometers. In this paper, an existing ... [more ▼]

In order to remotely monitor tension in a cable over time, an appropriate method is based on the natural frequencies of the cable measured by means of wireless accelerometers. In this paper, an existing method is extended to determine the tension in long or short shallow cables with small bending stiffness and arbitrary end conditions. First, a low-order analytical model is developed to compute the dynamic response of a given cable. Then, the unknown parameters such as the end conditions, the exact length of the cable and the tension in the cable are adjusted, using an iterative nonlinear least-square algorithm, until the computed natural frequencies and associated mode shapes match the measured ones. This procedure is finally validated with field measurements collected on long and short cables. [less ▲]

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See detailAdaptive method for detecting zero-velocity regions to quantify stride-to-stride spatial gait parameters using inertial sensors
Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege; Joris, Laura ULiege et al

in Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2019) (2019, February 25)

We present a new adaptive method that robustly detects zero-velocity regions to accurately and precisely quantify (1) individual stride lengths (SLs), (2) individual stride velocities (SVs), (3) the ... [more ▼]

We present a new adaptive method that robustly detects zero-velocity regions to accurately and precisely quantify (1) individual stride lengths (SLs), (2) individual stride velocities (SVs), (3) the average of SL, (4) the average of SV, and (5) the cadence during slow, normal, and fast overground walking conditions in young and healthy people. The measurements involved in the estimation of these spatial gait parameters are obtained using only one inertial measurement unit attached on a regular shoe at the level of the heel. This adaptive method reduced the integration drifts across consecutive strides and improved the accuracy and precision in the spatial gait parameter estimation. The validation of the proposed algorithm has been carried out using reference spatial gait parameters obtained from a kinematic reference system. The accuracy ± precision results were for SLs: 0.0 ± 4.7 cm, −0.7 ± 4.4 cm, and −5.8 ± 5.8 cm, during slow, normal, and fast walking conditions, respectively, corresponding to −0.1 ± 4.2 %, −0.5 ± 3.2 %, and −3.3 ± 3.0 % of the respective mean SL. The accuracy ± precision results were for SVs: 0.0 ± 2.9 cm/s, −0.7 ± 3.8 cm/s, and −6.7 ± 6.7 cm/s, during slow, normal, and fast walking conditions, respectively, corresponding to −0.6 ± 3.3 %, −0.1 ± 4.5 %, and −3.5 ± 3.1 % of the respective mean SV. These validation results show a good agreement between the proposed method and the reference, and demonstrate a fairly accurate and precise estimation of these spatial gait parameters. The proposed method paves the way for an objective quantification of spatial gait parameters in routine clinical practice. [less ▲]

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See detailEvolution of the trophy position along the tennis serve player’s development
Tubez, François ULiege; Schwartz, Cédric ULiege; Croisier, Jean-Louis ULiege et al

in Sports Biomechanics (2019)

The trophy position is a coaching cue for the tennis serve that usually corresponds to the racquet high point (RHP) during the preparatory action for the stroke. Mastering this position and its time of ... [more ▼]

The trophy position is a coaching cue for the tennis serve that usually corresponds to the racquet high point (RHP) during the preparatory action for the stroke. Mastering this position and its time of occurrence seems essential in overarm movements like in the tennis serve. Clinicians and coaches have a real interest in understanding the trophy position and its evolution during the development of the elite players at different ages. A 3D motion system was used to measure the kinematics of the serve. A group of high-level tennis players were selected for three different age groups: 8 adults (ITN 1), 8 teenagers (ITN 3) and 8 children (ITN 5–6). Results show a modified pattern sequence of the tennis serve between children and adult players. RHP appears earlier relative to impact for children (−0.54 ± 0.10 s) than for adults (−0.36 ± 0.11 s) and teenagers (−0.33 ± 0.05 s) (p = 0.007). At RHP, children present lower trunk transverse plane rotation (p < 0.003) and higher shoulder external rotation (p < 0.003). These positions for the child players may represent an increased risk of shoulder and trunk injury than for older players and contribute to a lower racquet resultant velocity at impact. [less ▲]

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See detailExperimental and numerical study of the second order moment of the first passage time of a steel strip subjected to forced and parametric excitations
Delhez, Elise ULiege; Vanvinckenroye, Hélène ULiege; Denoël, Vincent ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXVII (2019, January)

The first passage time is the time required for a stochastic process to leave a subdomain of the state space for the first time when starting from a given initial state in this subdomain. Analytical ... [more ▼]

The first passage time is the time required for a stochastic process to leave a subdomain of the state space for the first time when starting from a given initial state in this subdomain. Analytical studies of the first passage time of a linear Mathieu oscillator subjected to forced and parametric excitations defined as δ-correlated Brownian noises highlighted the existence of three behavioral regimes for the average first passage time. The current work describes the design and outcomes of an experimental study demonstrating the practical existence of these regimes for the second order moment of the first passage time. On the one hand, tests are carried out on an experimental set-up consisting in a pre-stressed strip subjected to forced and parametric stochastic excitations. On the other hand, a finite element model of the structure is built, updated and used to address the same problem using a numerical approach. Both the experimental tests and the numerical simulations produce mean square first passage time maps that provide evidence for the existence of the three foreseen behavioral regimes. The good match of the first passage time maps confirms the accuracy of the finite element model updating as well as the relevance of the theoretical model for this type of problem. [less ▲]

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See detailHow much do we rely on additivity and linearity of aerodynamic and aeroelastic loading models ?
Denoël, Vincent ULiege

Scientific conference (2018, December 14)

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See detailMixture model in high-order statistics for peak factor estimation on low-rise building
Rigo, François ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

in Proceedings of the XV Conference of the Italian Association for Wind Engineering (2018, December 10)

To design reliable structures, extreme pressures and peak factors are required. In many applications of Wind Engineering, their statistical analysis has to be performed taking into account the non ... [more ▼]

To design reliable structures, extreme pressures and peak factors are required. In many applications of Wind Engineering, their statistical analysis has to be performed taking into account the non-Gaussianity of the wind pressures. With the increasing precision and sampling frequency of pressure sensors, large short and local peak events are more usually captured. Their relevance is naturally questioned in the context of a structural design. Furthermore, the increasing computational power allows for accumulation and analysis of larger data sets revealing the detailed nature of wind flows around bluff bodies. In particular, in the shear layers and where local vortices form, it is commonly admitted that the Probability Density Function (PDF) of measured pressures might exhibit two or more significant components. These mixed flows can be modelled with mixture models [Cook (2016)]. Whenever several processes coexist, and when one of them is leading in the tail of the statistical distribution, as will be seen next in the context of corner vortices over a flat roof, it is natural to construct the extreme value model with this leading process and not with the mixed observed pressures. It is therefore important to separate the different processes that can be observed in the pressure histories. Once this is done, specific analytical formulations of non-Gaussian peak factors can be used to evaluate the statistics of extreme values [Kareem and Zhao (1994), Chen (2009)]. The separation of mixed processes is usually done by means of the PDF of the signals [Cook (2016)]. This information is of course essential to perform an accurate decomposition but it might be facilitated by considering higher rank information like auto-correlations and higher correlations like the triple or quadruple correlation. Indeed, the two phenomena that need to be separated and identified might be characterized by significantly different timescales, which are not reflected in the PDF. In this paper, the large negative pressures measured on a flat roof are analyzed and decomposed into two elementary processes, namely, the flapping corner vortex and the turbulent flow detaching from the sharp upstream edge. The full paper will finally show that an accurate decomposition of the recorded pressures into their underlying modes provides a more meaningful evaluation of the extreme pressures. [less ▲]

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See detailVIV response of a suspended sphere nearby the critical Reynolds number
Andrianne, Thomas ULiege; Rigo, François ULiege; Denoël, Vincent ULiege

Conference (2018, September 10)

The Vortex-Induced Vibration of a sphere connected to a flexible beam is investigated in air for Reynolds numbers including the critical value. For this value (ReC =3e5 ), wake disorganisation is expected ... [more ▼]

The Vortex-Induced Vibration of a sphere connected to a flexible beam is investigated in air for Reynolds numbers including the critical value. For this value (ReC =3e5 ), wake disorganisation is expected in a static configuration. This fundamental fluid-structure interaction characterised by an axisymmetric configuration leads to vibrations in the lateral and longitudinal directions. Similarly to the well-known circular cylinder, a lock-in phenomenon will take place due to the effect of the motion of the body on the shedding process. An experimental aeroelastic model is designed, instrumented and tested in the wind tunnel of University of Liège. The objective is twofold: (i) solve a practical wind-engineering problem (a spherical suspended streetlight) and (ii) propose a fundamental investigation of the VIV of a smooth sphere for sub-critical and critical Reynolds numbers. [less ▲]

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See detailEccentric training for tendon healing after acute lesion: a rat model
Kaux, Jean-François ULiege; Libertiaux, Vincent; Leprince, Pierre ULiege et al

in Towards healthy tendon ageing... (2018, September)

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See detailPlatelet-Rich Plasma (PRP) and tendon healing: comparison between fresh and frozen-thawed PRP
Kaux, Jean-François ULiege; Libertiaux, Vincent; Dupont, Laura ULiege et al

in Towards healthy tendon ageing... (2018, September)

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See detailNumerical and experimental study of first passage time of a steel strip subjected to forced and parametric excitations
Delhez, Elise ULiege; Vanvinckenroye, Hélène ULiege; Golinval, Jean-Claude ULiege et al

in Proceedings of the 28th International Conference on Noise and Vibration Engineering (2018, September)

The first passage time refers to the time required for a dynamical system to reach a target energy level for the first time, departing from a known initial state. Analytical studies of the first passage ... [more ▼]

The first passage time refers to the time required for a dynamical system to reach a target energy level for the first time, departing from a known initial state. Analytical studies of the first passage time of a linear Mathieu oscillator under stochastic forced and parametric excitations defined as Brownian white noises identified three behavioral regimes for the first passage time. The current work describes the design and use of an experimental set-up in order to validate the existence of the regimes. This paper successively describes the design and the finite element modeling of the set-up consisting in a pre-stressed steel strip, the reduction of the system to a single-degree-of-freedom system to match the framework of the theory, numerical studies on the influence of the frequency bands of the excitations on the first passage time and the experimental tests. Qualitatively, two of the three regimes are successfully observed in the experiment. Quantitatively, a good match is observed between the experimental and model results. [less ▲]

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See detailEffect of an exhaustion closed chain exercise on the EMG activity of scapular muscles stabilizers
Schwartz, Cédric ULiege; Deby, Morgan ULiege; Tooth, Camille ULiege et al

Poster (2018, July)

The aim of the study was to study the evolution of the EMG activity of stabilizers of the scapula during an exhaustion exercise based on the Knee Push Up Plus exercise (KPUP) to detect the appearance of ... [more ▼]

The aim of the study was to study the evolution of the EMG activity of stabilizers of the scapula during an exhaustion exercise based on the Knee Push Up Plus exercise (KPUP) to detect the appearance of fatigue. Ten volunteers (men, 26+/-8 years old, 181+/-9 cm, 77+/-11 kg) performed a KPUP exercise until exhaustion. Surface EMG was measured for the lower and upper trapezius and the serratus anterior muscles. The results show that the exhaustion exercise have induced fatigue for the upper trapezius and serratus anterior muscles. On the contrary, our results do not show fatigue in the lower trapezius. [less ▲]

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See detailVortex induced vibrations of rectangular cylinders arranged on a grid
Rigo, François ULiege; Denoël, Vincent ULiege; Andrianne, Thomas ULiege

in Journal of Wind Engineering and Industrial Aerodynamics (2018)

A grid arrangement of hundred rectangular cylinders fixed to the facade of a house generates strong and disturbing mono-harmonic noise. The cross-flow vibration of the rectangular cylinders is identified ... [more ▼]

A grid arrangement of hundred rectangular cylinders fixed to the facade of a house generates strong and disturbing mono-harmonic noise. The cross-flow vibration of the rectangular cylinders is identified as the origin of the noise. The present article proposes a complete investigation of the Vortex Induced Vibration (VIV) combined with a grid effect. It is based on in situ measurements, numerical (finite elements and Computational Fluid Dynamics (CFD)) and extensive wind tunnel modelling. A comparison between unsteady pressure tap measurements and CFD results allow to understand the vortex shedding process and synchronization type depending on the wind incidence and spacing of the cylinders. On the basis of this multi-approaches parametric investigation, a deep understanding of the VIV-grid phenomenon enables to propose two mitigation techniques. These techniques are tested and their effectiveness is reported in terms of vibration amplitude and acoustic intensity. [less ▲]

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See detailEffects of Allogeneic Platelet-Rich Plasma (PRP) on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description
Greimers, Laura; Drion, Pierre ULiege; Colige, Alain ULiege et al

in Journal of Visualized Experiments (2018), 133

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a lesion in the Achilles tendon; prepare PRP and ... [more ▼]

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a lesion in the Achilles tendon; prepare PRP and inject it (or the saline solution); remove the tendon; and perform biomechanical, molecular, and histological evaluations. At each step, all the procedures and methods are described in detail, so they can be reproduced easily. Achilles tendons have been surgically sectioned (removal of a 5-mm long section). Afterwards, PRP or saline solution was injected to study whether PRP has a positive effect on the healing of the tendon. Three groups of 40 animals (a total of 120 rats were used in this study) were subdivided into 2 subgroups: PRP injection group and a saline injection control group. Rats were sacrificed at increasing time points (Group A: 5 days; Group B: 15 days; Group C: 30 days) and tendons were removed. 90 tendons underwent biomechanical testing before performing transcriptomic analysis and the 30 remaining tendons were submitted to histological analysis. [less ▲]

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See detailWhich tool for a tennis serve evaluation? A review
Tubez, François ULiege; Schwartz, Cédric ULiege; Paulus, Julien ULiege et al

in International Journal of Performance Analysis in Sport (2018)

For coaches, the most common and easiest way to analyse the tennis serve is to refer to their own vision. However, human vision is insufficient to observe high-speed motion with great precision. With the ... [more ▼]

For coaches, the most common and easiest way to analyse the tennis serve is to refer to their own vision. However, human vision is insufficient to observe high-speed motion with great precision. With the improvement of technology, it is now possible to study the gesture from a quantitative point of view. The quantitative evaluation of the tennis serve focuses on the kinematics and kinetics of the player but also on the stroke result, which includes the ball speed and the ball trajectory. This review aims to highlight the current tools available for players, coaches, medical staffs and biomechanical researchers, to evaluate the tennis serve. This overview will provide information to the player’s entourage in order to choose the right tools depending on their specific purposes. All of these tools can be applied in performance improvement and injury prevention. [less ▲]

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See detailAnalyse des Structures I
Denoël, Vincent ULiege

Learning material (2018)

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See detailClosed-form response of a linear fractional visco-elastic oscillator under arbitrary stationary input
Denoël, Vincent ULiege

in Proceedings of the Eigth International Conference on Computational Stochastic Dynamics (2018)

Abstract This paper studies the structural response of a single degree-of- freedom structure including a fractional derivative constitutive term. Unlike usual existing models for this kind of structure ... [more ▼]

Abstract This paper studies the structural response of a single degree-of- freedom structure including a fractional derivative constitutive term. Unlike usual existing models for this kind of structure, the excitation is not necessarily a Markovian process but it is slowly varying in time, so that a timescale separation is used. Following the general formulation of the Multiple Timescale Spectral Analysis [#Denoel2015], the solution is developed as a sum of background and resonant components. Because of the specific shape of the frequency response function of a system equipped with a fractional viscoelastic device, the background component is not simply obtained as the variance of the loading divided by the stiffness of the system. On the contrary the resonant component is expressed as a simple extension of the existing formulation for a viscous system, at least at leading order. As a validation case, the proposed solution is shown to recover similar results (in the white noise excitation case) as former studies based on a stochastic averaging approach [#SPA97, #DIP14]. A better accuracy is however obtained in case of very small fractional exponent. Another example related to the buffeting analysis of a linear fractional viscoelastic system demonstrates the accuracy of the proposed formulation for colored excitation. [less ▲]

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