Portail HAL UHA (Université de Haute-Alsace)
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Pyrolysis and combustion experiments on a wood pellet under low or high heating ramps and associated gaseous emissions
No full textInternational audienceWood pellets are commonly used for heat and energy production in domestic or industrial boilers. When they fall into the combustion zone, they first go through a pyrolysis stage before the combustion one. They are submitted to high temperature ramps. The overall combustion process leads to gaseous and particulate emissions that may be harmful to residents living close to the exhaust. For the present study, pyrolysis and combustion experiments were performed on a single wood pellet in a drop tube furnace. A temperature ramp of approximately 5 ◦C/min was applied and the sample mass was continuously recorded. The mass and mass rate curves were compared to that obtained for pellet sawdust in a thermobalance under the same temperature ramp. In the pyrolysis case, kinetic modeling was performed coupling the Extended Independent Parallel Reaction model and a thermal model to take into account the thermal diffusional limits inside the pellet. In the combustion case, the pellet is being degraded in a unique stage. Pyrolysis and combustion experiments were also performed under isothermal temperatures between 400 and 900 ◦C and different oxygen concentrations. During both pyrolysis and combustion experiments, the main gaseous emissions were continuously measured. From theseexperiments and analyses, it is possible to determine the optimal experimental conditions that lead to minimal emissions
Les découplages comme des régulations disjointes
No full textInternational audienceIn this article, we propose a theoretical development of the concept of decoupling, which is useful for analysing industrial relations. Many authors define decoupling as a process of organisational responses to institutional pressures. While the 'policy-practice' decoupling described by Bromley and Powell ( 2012) is similar to the case described by Meyer and Rowan (1977), where the choice is intentional, associated with a simulacrum of evaluation, the 'means-ends' decoupling is reminiscent of the situations described by Reynaud. In this case, managers intend to apply institutional standards, which they have reproduced in the form of procedures, but fail to apply them under pressure from operational staff. What can SRT contribute to the analysis of decoupling? We begin by reviewing the state of the art on the concept of decoupling, and in particular the work of TNI researchers taking an epistemological approach based on social constructivism. We then show that SRT, which is partly compatible with this latter approach, provides an interpretation that breaks with a multi-level analysis by considering the rule production processes of all social groups without ranking them. We show that TRS understands this phenomenon as a form of disjointed regulation, distinguishing three categories according to the nature of the negotiations:• Disjointed 'avoidance' regulations explain the 'policy-practice' decoupling, where management is aware of the gap between its institutional norms and operators' rules and chooses to avoid confrontation. • Conflictual" disjointed regulations explain the "means-ends" decoupling, with an alignment of structures desired by management but thwarted by the power of professionals. • Ignorance" disjointed regulations explain the decoupling caused by management's ignorance of autonomous rules. Teams of operators may also be unaware of the control rule.Dans cet article, nous proposons un développement théorique sur le concept de découplage, quis’avère utile pour analyser les relations industrielles. Beaucoup d’auteurs définissent le découplagecomme un processus de réponses des organisations aux pressions institutionnelles. Si ledécouplage « politique-pratique » décrit par Bromley et Powell (2012) rejoint le cas de figure décritpar Meyer et Rowan (1977), où le choix est intentionnel, associé à un simulacre d’évaluation, ledécouplage « moyens-fins » rappelle les situations décrites par Reynaud. Dans ce cas, les dirigeantsont l’intention d’appliquer les normes institutionnelles, qu’ils ont reproduites sous forme deprocédures, mais échouent à les appliquer sous la pression des opérationnels. Pour autant, la TNIn’explique par le processus sous-jacent au découplage en négligeant la dimension politique dans laproduction de normes et de règles, ce que la TRS permet à travers le concept de régulation sociale.En quoi le découplage dans les organisations est-il une forme de régulation sociale ? Nous faisonstout d’abord un état de l’art sur le concept de découplage, en particulier les travaux de chercheursde la TNI inscrits dans une approche épistémologique du constructivisme social, en précisant leurslacunes. Nous montrons ensuite que la TRS, compatible en partie avec cette dernière approche,apporte une lecture qui rompt avec une analyse multiniveau en considérant les processus deproduction de règles de tous les groupes sociaux sans les hiérarchiser. Nous montrons que la TRSappréhende ce phénomène comme une forme de régulations disjointes en distinguant troiscatégories selon l’existence de négociation et d’accord :Les régulations disjointes « d’évitement » expliquent le découplage « politique-pratique », oùla direction a connaissance de l’écart entre ses normes institutionnelles et les règles desopérateurs et fait le choix d’éviter la confrontation.Les régulations disjointes « conflictuelles » expliquent le découplage « moyens-fins » avec unalignement des structures voulu par la direction, contrariée par le pouvoir desprofessionnels.Les régulations disjointes « de méconnaissance » expliquent le découplage provoqué parune absence de connaissance des règles autonomes par la direction. Les équipesd’opérateurs peuvent aussi ignorer la règle de contrôle.Ces formes de disjonction entre les espaces sociaux (institutions, sommet stratégique, groupesd’opérateurs) expliquent les différents types de découplages à l’oeuvre dans un secteuréconomique, ouvrant des pistes de recherches stimulantes pour le futur
Variations rythmiques et conscience générique. Réflexions sur l’usage du vers dans quelques romans du XIIIe siècle
No full textInternational audienceThis paper focuses on the relationship between generic consciousness and theuse of versification in the thirteenth-century French verse romances. By studyingthe rhythmic variations in the works attributed to Raoul de Houdenc, the papershows how these variations are rooted in several generic traditions and engage thehorizon of expectation and participation of its audiences
Présentation : La Subjectivité dans la retraduction collaborative
No full textInternational audienceIntroduction au numéro thématique de TTR, La Subjectivité dans la retraduction collaborative
A review of AutoML optimization techniques for medical image applications
No full textInternational audienceAutomatic analysis of medical images using machine learning techniques has gained significant importance over the years. A large number of approaches have been proposed for solving different medical image analysis tasks using machine learning and deep learning approaches. These approaches are quite effective thanks to their ability to analyze large volume of medical imaging data. Moreover, they can also identify patterns that may be difficult for human experts to detect. Manually designing and tuning the parameters of these algorithms is a challenging and time-consuming task. Furthermore, designing a generalized model that can handle different imaging modalities is difficult, as each modality has specific characteristics. To solve these problems and automate the whole pipeline of different medical image analysis tasks, numerous Automatic Machine Learning (AutoML) techniques have been proposed. These techniques include Hyper-parameter Optimization (HPO), Neural Architecture Search (NAS), and Automatic Data Augmentation (ADA). This study provides an overview of several AutoML-based approaches for different medical imaging tasks in terms of optimization search strategies. The usage of optimization techniques (evolutionary, gradient-based, Bayesian optimization, etc.) is of significant importance for these AutoML approaches. We comprehensively reviewed existing AutoML approaches, categorized them, and performed a detailed analysis of different proposed approaches. Furthermore, current challenges and possible future research directions are also discussed.</div
Où va le reporting en matière de RSE après la transposition de la directive CSRD ?
No full textInternational audienc
Unconventional Optical Imaging for Biology
No full textInternational audienceOptical imaging of biological systems has undergone spectacular development in recent years, producing a quantity and a quality of information that, just twenty years ago, could only be dreamed of by physicists, biologists and physicians.Unconventional imaging systems provide access to physical quantities –phase, absorption, optical index, the polarization property of a wave or the chemical composition of an object – not accessible to conventional measurement systems. To achieve this, these systems use special optical setups and specific digital image processing to reconstruct physical quantities. This field is also known as computational imaging.This book presents various non-conventional imaging modalities developed for the biomedical field: wave front analysis imaging, digital holography/tomography, optical nanoscopy, endoscopy and single-sensor imaging. Experimental setups and reconstruction algorithms are presented for each modality
Journalisme et I.A : une question de discours ?
No full textInternational audienceCette communication met en perspective les principaux discours médiatiques dans la Presse nationale française qui traitent des usages et de l’intégration de l’Intelligence artificielle (IA) dans le journalisme. L’objectif est de mettre au jour les fondements de légitimation ou de délégitimation de cette technologie dans la mission d’informer. L’hypothèse avancée est que ces discours en circulation sont très souvent déterminés par la façon de concevoir la pratique du journalisme. La dissémination de ces types de discours finit par modeler les perceptions de ce qui constitue le travail de l’information et, par extension, d’un journalisme augmenté par les IA
Enhancing photothermal energy transduction through inter- and intramolecular interactions of multiple two-photon dyes appended onto Calix[4]arene
No full textInternational audienceOrganic dyes-based photothermal agents (OPTAs) have received increasing attention as alternative to inorganic materials due to their higher biocompatibility and extensive diversification. Maximizing nonradiative deexcitation channels is crucial to improve the photothermal conversion efficiency (PCE) of OPTAs. This is typically achieved through individual molecular design or collective enhancement using supramolecular strategies. Furthermore, photothermal therapy (PTT) generally relies on linear one-photon absorption of the light source by the OPTA, with less consideration given to nonlinear two-photon absorption (2PA) strategies, despite their potential benefits. Here, a synergistic strategy, which combines intramolecular and intermolecular quenching, is employed to maximize the photothermal efficiency of diphenylamino-substituted distyryl dicyanobenzene (DSB), an outstanding two-photon-absorbing chromophore. One to three DSB units have been introduced on the conic p-tert-butyl-calix[4]arene (CX), serving as a preorganizing platform to allow aggregate formation and promote intramolecular quenching within the multichromophoric systems. Importantly, the multichromophoric molecules had very high two-photon absorption capabilities with cross sections (δ2PA) reaching maximal values of 3290 GM at 810 nm. Experimental data accompanied by large-scale molecular dynamics simulations and time-dependent density functional theory calculations shed light onto the interaction mechanism in those multiple DSB-appended CX compounds to rationalize their optical properties. Then, the formulation with Pluronic F127 amphiphile yields water-dispersible nanoprecipitates (Nps), in which the PCE is further maximized and the photobleaching is reduced due to the combination of intra- and intermolecular quenching. The high two-photon absorption in the near-infrared (NIR) window associated with the high PCE of these nanosized OPTAs could serve as a basis to future in vivo 2P-PTT applications