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See detail“Death is the only real utopia”: Adorno and Kluge on television
Cormann, Grégory ULiege

Conference (2018, May)

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See detailParameter reduction in nonlinear state-space identification of hysteresis
Esfahani, Alireza; Dreesen, Philippe; Tiels, Koen et al

in Mechanical Systems & Signal Processing (2018), 104

Recent work on black-box polynomial nonlinear state-space modeling for hysteresis identification has provided promising results, but struggles with a large number of parameters due to the use of ... [more ▼]

Recent work on black-box polynomial nonlinear state-space modeling for hysteresis identification has provided promising results, but struggles with a large number of parameters due to the use of multivariate polynomials. This drawback is tackled in the current paper by applying a decoupling approach that results in a more parsimonious representation involving univariate polynomials. This work is carried out numerically on input-output data generated by a Bouc-Wen hysteretic model and follows up on earlier work of the authors. The current article discusses the polynomial decoupling approach and explores the selection of the number of univariate polynomials with the polynomial degree. We have found that the presented decoupling approach is able to reduce the number of parameters of the full nonlinear model up to about 50%, while maintaining a comparable output error level. [less ▲]

See detailTextes en réseau: théâtre et roman dans les manuscrits médiévaux
Henrard, Nadine ULiege; Morato, Nicola ULiege

Scientific conference (2018, April 26)

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See detailDevelopment of a non-toxic and non-denaturing formulation process for encapsulation of SDF-1α into PLGA/PEG-PLGA nanoparticles to achieve sustained release
Haji Mansor, Muhammad; Najberg, Mathie; Contini, Aurélien et al

in European Journal of Pharmaceutics & Biopharmaceutics (2018), 125

Chemokines are known to stimulate directed migration of cancer cells. Therefore, the strategy involving gradual chemokine release from polymeric vehicles for trapping cancer cells is of interest. In this ... [more ▼]

Chemokines are known to stimulate directed migration of cancer cells. Therefore, the strategy involving gradual chemokine release from polymeric vehicles for trapping cancer cells is of interest. In this work, the chemokine stromal cell-derived factor-1α (SDF-1α) was encapsulated into nanoparticles composed of poly-(lactic-co-glycolic acid) (PLGA) and a polyethylene glycol (PEG)-PLGA co-polymer to achieve sustained release. SDF-1α and lysozyme as a model protein, were firstly precipitated to promote their stability upon encapsulation. A novel phase separation method utilising a non-toxic solvent in the form of isosorbide dimethyl ether was developed for the individual encapsulation of SDF-1α and lysozyme precipitates. Uniform nanoparticles of 200–250 nm in size with spherical morphologies were successfully synthesised under mild formulation conditions and conveniently freeze-dried in the presence of hydroxypropyl-β-cyclodextrin as a stabiliser. The effect of PLGA carboxylic acid terminal capping on protein encapsulation efficiency and release rate was also explored. Following optimisation, sustained release of SDF-1α was achieved over a period of 72 h. Importantly, the novel encapsulation process was found to induce negligible protein denaturation. The obtained SDF-1α nanocarriers may be subsequently incorporated within a hydrogel or other scaffolds to establish a chemokine concentration gradient for the trapping of glioblastoma cells. © 2017 Elsevier B.V. [less ▲]

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See detailMulti-objective optimization of cost-efficient neotissue growth inside 3D scaffolds using evolutionary algorithms
Mehrian, Mohammad ULiege; olofsson, Simon; Misener, Ruth et al

Scientific conference (2018, March 26)

Tissue engineering is a fast progressing domain where solutions are provided for organ failure or tissue damage. Computer models can facilitate the design of optimal production process conditions leading ... [more ▼]

Tissue engineering is a fast progressing domain where solutions are provided for organ failure or tissue damage. Computer models can facilitate the design of optimal production process conditions leading to robust and economically viable products. We developed a computational model describing the neotissue growth (cells + their ECM) inside 3D scaffolds in a perfusion bioreactor. Here we apply multi-objective optimization (MOO) to maximize neotissue growth whilst minimizing the cost coming from medium refreshment and associated labor. [less ▲]

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See detailComputational modelling of human mesenchymal stem cell proliferation and extra cellular matrix production in 3D porous scaffolds in a perfusion bioreactor
Mehrian, Mohammad ULiege; Papantoniou, Ioannis; Lambrechts, Toon et al

Scientific conference (2018, March 26)

3D porous scaffolds are frequently used in tissue engineering (TE) applications in combination with bioreactor systems because of their ability to induce reproducible culture conditions that can control ... [more ▼]

3D porous scaffolds are frequently used in tissue engineering (TE) applications in combination with bioreactor systems because of their ability to induce reproducible culture conditions that can control specific cell behavior such as proliferation and extracellular matrix (ECM) production. A computational model describing neotissue growth inside 3D scaffolds in a perfusion bioreactor was developed, with neotissue being considered the combination of cells and their extra cellular matrix. In the model, the speed of neotissue growth depends on the flow-induced shear stress, curvature and the local concentrations of oxygen, glucose and lactate. The goal of this study is to make a distinction between the cell and the ECM fraction within the neotissue in the model to allow for a more detailed validation and optimization of the process. [less ▲]

Peer Reviewed
See detailConservation Ethics in the 21th Century: Towards an Extended Toolkit
Houbart, Claudine ULiege; Dawans, Stéphane ULiege

Conference (2018, March)

In his now classic essay on the « Régimes d’historicité », the French historian François Hartog (2003) has very well described the effect of globalisation, democratisation and mass consumerism on our ... [more ▼]

In his now classic essay on the « Régimes d’historicité », the French historian François Hartog (2003) has very well described the effect of globalisation, democratisation and mass consumerism on our relation with the past and thus, with heritage. In the course of the 1970’s, at a time when the ink of the Venice Charter was barely dry, postmodernity triggered a loss of collective anchoring and memory, paradoxically accompanied by an amplification of the thirst for commemorations, in the name of identity or heritage. Pierre Nora’s great endeavour « Les lieux de mémoire », fully corresponds to this « presentism » era, including aside from monuments, museum and archives, intellectual constructions such as the Larousse encyclopaedia (Nora 1989). It very well illustrates the « extension of the heritage domain » as defined by the sociologist Nathalie Heinich (2009). In our « post-monumental » era, anything can possibly become heritage, regardless of scale, of artistic qualities, of age or ontological degree – from tangible to intangible. This is a sign of times. Following the example of Nelson Goodman replacing the essentialist definitions of art with the question « When is there art ? » (Goodman 1976), we should consider focusing on a dynamic and operational definition of heritage. The question « When is there heritage ?» better correspond to contemporary cultural studies and our attempt to understand « heritagization »; it contains the idea of a performative action, implying new actors, new dynamics, new process, new research questions, new difficulties and new opportunities. And by necessity new concepts. We are far from rejecting theories from the past which provided us with effective and stimulating tools. But who could still imagine today, in the situation we described, that any system could fully encompass the heritage reality as the grand theories – Brandi, Riegl,… – succeeded to do? The repeated attempts to get the Venice charter revised from the 1970’s on (Houbart 2014), and the multiplication of thematic documents and charters are the best illustration of this impossibility. But while postmodern thinkers made us suspicious towards large systems, they also made us more modest and above all, more inclined to respect « bricolage », as a most helpful attitude after a shipwreck. We believe that the current return to a case by case approach – as promoted from the interwar period by theoreticians such as Ambrogio Annoni (1946) – often mostly relying on practical constraints such as reuse and technical performances, combined with the use of decontextualised concepts – separated articles from the Venice Charter, for example – and practices – using the Ise shrine periodical rebuilding to advocate any reconstruction project – doesn’t mean to accept a cynical relativism in answer to the cause of a capital-intensive machine. But in practice, we cannot deny that it has sometimes been the case: the clearest examples are the debates addressing the reconstruction of monuments all over Europe, based on a jumble of arguments confusing the pure mercantilism of the tourism industry or unconfessed political reasons with post-conflict identity issues or religious traditions (Monumental 2010). Reflecting on such reconstruction projects, raising questions of identity, has convinced us of the incompleteness of the toolkit we inherited from 20th century theoreticians. Though still perfectly relevant to address the issues that were already present at the time when they were elaborated, they might prove inappropriate to address new types of heritage, new concerns, new issues such as cultural tourism, inclusive approaches, modern heritage or the digital turn. In this context, we have been drawn to look at texts outside the conservation sphere, starting from ontology of art and analytical philosophy. We discovered that taking a step to the side could provide a stimulating insight on heritage conservation problems. In fact, it is not surprising that, facing what many have called a heritage inflation, some new actors could help us. Now that heritage has quitted the monuments sphere to encompass any material or immaterial reality worthy of conservation and that the expert point of view is challenged by the ones of a broad range of stakeholders, from the user to the investor, it becomes interesting to look at this reality from different points of view borrowed to a wide range of human sciences such as law, communication, aesthetics, semiotics, anthropology or philosophy, to name a few. Together with our colleague Muriel Verbeeck, we are currently gathering texts in order to propose an anthology that could complement the existing ones in helping to fill conceptual gaps and throw a reinvigorating light on new problems raising old questions. The originality of the project is to chose most texts outside the conservation world, and to address movable and immovable heritage at the same time. During our presentation, we will provide some examples of the usefulness of these new concepts, some already known by a number of conservators – such as the distinction proposed by Nelson Goodman between allography and autography (Goodman 1976) –, some not – the impact of intention on identity, based on texts by Theodore Scaltsas (1981), for example –, and will encourage the members of the committee who might be interested in this approach to contribute to the project. [less ▲]

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See detailOpal-like photoanodes with photonic effects in macroporous perovskite solar cells
Dewalque, Jennifer ULiege; Baron, Damien ULiege; Spronck, Gilles ULiege et al

Poster (2018, February 28)

Organic-inorganic metal halide perovskite compounds, used either in mesoscopic or planar solar cells architectures, have allowed preparing highly efficient solid-state devices (>20%). In mesoscopic solar ... [more ▼]

Organic-inorganic metal halide perovskite compounds, used either in mesoscopic or planar solar cells architectures, have allowed preparing highly efficient solid-state devices (>20%). In mesoscopic solar cells, a mesoporous TiO2 scaffold is incorporated into the cells. However, because of the small pore size compared to the wavelengths of visible light, the scaffold barely scatters light. In this work, we propose to design periodically structured TiO2 scaffold from colloidal crystal templating fabrication method. Polystyrene beads with diameters comparable to visible light wavelengths are used as structuring agent. The resulting opal-like photonic structure will strongly interact with light and increase light harvesting. The photoanode microstructure is characterized by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). In parallel, light interaction is modeled in order to find the best compromise in terms of photonic architecture. Sunlight absorption by the solar cells is presented and discussed with dependency of pore sizes and number of opal-like layers. [less ▲]

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See detailSynthesis of bimetallic catalysts supported on alumina by an aqueous sol-gel process
Lambert, Stéphanie ULiege

Conference (2018, February 20)

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO+H2) since this process presents the advantage of being renewable without ... [more ▼]

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO+H2) since this process presents the advantage of being renewable without emitting CO2. However, in practical applications, there are still some technical problems due to high concentration of tars in the outlet gas, which can condensate and clog the pipes. Previous studies have highlighted the fact that the tar elimination via catalytic reforming seem to be the more practical and economical solution. Catalysts were synthesized by an aqueous sol-gel process to develop γ-Al2O3 doped with 10 wt.% of nickel and 2 wt.% of a second dopant (Co, Cu, Fe, Mn, Mo). Before their adding in AlOOH sol, metallic dopants were complexed with (OCH3)3-Si-(CH2)3-NH-(CH2)2-NH2 (EDAS) to increase their dispersion by cogelation between EDAS and AlOOH clusters. All the samples were tested for toluene reforming at 650°C for 300 min. No previous reduction step has been realized. Each 15 min, injection was sent to a GC Compac for analysis. For samples Al2O3-10Ni-2Mn and Al2O3-10Ni-2Mo, the addition of Mn or Mo allows increasing the toluene conversion up to 100%, whereas all other samples present lower toluene conversion (around 30%). Taking into account the benzene selectivity, it is observed that Mn and Mo are both elements that favor the degradation of aromatic groups. In term of carbon deposit during catalytic test, sample Al2O3-10Ni-2Mn is the most interesting doping since only 0.04 gcarbon gcata-1 is depicted by TG-DSC measurement after catalytic test. [less ▲]

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See detailMarcel Schmitz: tape planner
Dejasse, Erwin ULiege

in Epidemiology and Psychiatric Sciences (2018), 27(1), 22-23

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See detailSpurious intraoperative PTH results observed with 2(nd), but not with 3(rd) generation PTH assays.
Cavalier, Etienne ULiege; SCHLECK, Marie-Louise ULiege; Souberbielle, Jean-Claude

in Clinica Chimica Acta (2018), 477

We report here an interference that has been observed with 2(nd) generation PTH assays (PTH2), but not with 3(rd) generation PTH ones (PTH3), during PTH monitoring occurring in a surgical intervention for ... [more ▼]

We report here an interference that has been observed with 2(nd) generation PTH assays (PTH2), but not with 3(rd) generation PTH ones (PTH3), during PTH monitoring occurring in a surgical intervention for the resection of a parathyroid adenoma. The patient was cured and calcium levels returned to normal the next day, but PTH did not decrease with PTH2 whereas it decreased by 50% with PTH3 assays during the intervention. The reason is probably a PTH fragment released by the parathyroid gland during surgery. This fragment possesses the C-terminal part of the peptide but lacks the first amino-acids and may thus be considered as a member of the non-(1-84) PTH fragments family. It has also a longer half-life than 1-84 PTH. To avoid reporting spurious results to the surgeons, we thus recommend using PTH3 assays for monitoring of intra-operative PTH. [less ▲]

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See detailLocating nonlinearity in mechanical systems: A dynamic network perspective
Noël, Jean-Philippe ULiege; Schoukens, Maarten; Van den Hof, Paul

in Proceedings of the International Modal Analysis Conference (IMAC) XXXV (2018, February)

Though it is a crucial step for most identification methods in nonlinear structural dynamics, nonlinearity location is a sparsely addressed topic in the literature. In fact, locating nonlinearities in ... [more ▼]

Though it is a crucial step for most identification methods in nonlinear structural dynamics, nonlinearity location is a sparsely addressed topic in the literature. In fact, locating nonlinearities in mechanical systems turns out to be a challenging problem when treated nonparametrically, that is, without fitting a model. The present contribution takes a new look at this problem by exploiting some recent developments in the identification of dynamic networks, originating from the systems and control community. [less ▲]

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See detailSystem identification of jointed structures: Nonlinear modal testing vs. State-space model identification
Scheel, Maren; Kleyman, Gleb; Tatar, Ali et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXV (2018, February)

Two approaches for experimental identification of the nonlinear dynamical characteristics of jointed structures are investigated, (a) Nonlinear Modal Testing, (b) State-Space Model Identification. Both ... [more ▼]

Two approaches for experimental identification of the nonlinear dynamical characteristics of jointed structures are investigated, (a) Nonlinear Modal Testing, (b) State-Space Model Identification. Both require only minimal a priori knowledge of the specimen. For method (a), the definition of nonlinear modes as periodic motions is used, in its generalized formulation recently proposed for nonconservative systems. The theoretically required negative damping compensating the frictional dissipation is experimentally realized by properly controlled excitation. This permits the extraction of modal frequencies, damping ratios and vibrational deflection shapes as a function of the vibration level. For method (b), a state-space model with multivariate polynomial nonlinear terms is identified from the vibration response to a properly designed excitation signal. Both methods are applied to a structure with bolted joints. The quality of the extracted modal and state-space models, respectively, is assessed by comparing model-based predictions of the forced vibration response to reference measurements. [less ▲]

See detailModel updating of a wing-engine structure with nonlinear connections
Song, Mingming; Renson, Ludovic; Noël, Jean-Philippe ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXV (2018, February)

This paper investigates the performance of a Bayesian model updating approach using nonlinear normal modes (NNMs). The proposed approach is applied to a wing-engine structure tested in the laboratory. The ... [more ▼]

This paper investigates the performance of a Bayesian model updating approach using nonlinear normal modes (NNMs). The proposed approach is applied to a wing-engine structure tested in the laboratory. The structure response to a broadband input excitation is measured experimentally. The structure NNMs are then extracted from the measured data by combining a frequency-domain nonlinear subspace identification method with numerical continuation technique. An initial finite element model of the wing-engine structure is built in Matlab and its linear stiffness parameters and the coefficients of the local nonlinearities are selected as the updating parameters. The joint posterior probability distribution of the model parameters is estimated based on their prior distribution and the likelihood function which is defined as a Gaussian distribution of error function. The error function in this study is defined as the difference between model-predicted and identified NNMs at different energy levels. The calibrated model is then used to predict the structure response (NNMs and time history), taking into account model parameters uncertainties and modeling errors. The model predictions are compared with a set of experimental results that were not used in the calibration process and only considered for validation purpose. [less ▲]

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See detailSubspace-based identification of a distributed nonlinearity in time and frequency domains
Anastasio, Dario; Marchesiello, Stefano; Noël, Jean-Philippe ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXV (2018, February)

Nonlinear system identification has become of great interest during the last decades. However, a common and shared framework is not present yet, and the identification may be challenging, especially when ... [more ▼]

Nonlinear system identification has become of great interest during the last decades. However, a common and shared framework is not present yet, and the identification may be challenging, especially when real engineering structures are considered with strong nonlinearities. Subspace methods have proved to be effective when dealing with local nonlinearities, both in time domain (TNSI method) and in frequency domain (FNSI method). This study reports an improvement for both methods, as a first attempt to account for distributed nonlinearities, which is still an open question in the research community. A numerical beam under moderately large oscillations that exhibits geometric nonlinearity is considered. The object of the identification process is to exploit its behavior through the correct identification of the parameters that define the nonlinearity. Results show a high level of confidence between the two methods, and suggest that a more complete analysis of distributed nonlinear phenomena can be conducted based on these approaches. [less ▲]