Étude exploratoire de la phase d’usage des produits électroniques en vue de minimiser les impacts environnementaux : le cas du téléviseur

À cause de leur impact environnemental élevé, les déchets d’équipements électriques et électroniques (DEEE) sont un problème majeur pour les pays développés. La consommation importante de produits électroniques, dont la durée d’utilisation est de plus en plus courte, a entrainé une production croissante de DEEE. C’est dans ce contexte que l’Union européenne a instauré en 2003 la responsabilité élargie des producteurs (REP). Cet outil de politique environnementale a rendu légalement responsables les fabricants de la mise en oeuvre et du financement d’un programme d’intendance des DEEE. Alors que la REP vise principalement le traitement écologique des DEEE, cet instrument ne permet pas de réduire les quantités considérables qui sont produites par les consommateurs. Cette situation est d’autant plus inquiétante que les gains environnementaux obtenus, grâce à l’implantation de la REP, ont été annulés au regard de l’augmentation continue de la consommation de biens électroniques à l’échelle mondiale. En réponse à cette problématique, la présente thèse porte sur les pratiques de l’usager au cours de la phase de consommation des appareils électroniques (aussi appelée phase d’usage). Cette étape du cycle de vie regroupe l’achat, l’utilisation, la réparation et la mise au rebut des biens. Une approche qualitative de type exploratoire faisant appel à l’étude de cas a été utilisée. Le téléviseur, retenu comme cas d’étude, illustre des enjeux partagés par plusieurs équipements électroniques, tels que : la fréquente mise sur le marché de nouveaux modèles, le bas prix d’acquisition comparé au coût de la réparation et l’influence de la mode sur les choix effectués par le consommateur. Ces facteurs facilitent le remplacement des biens et, par conséquent, pourraient entrainer leur fin de vie prématurée qui se matérialise à travers différentes formes d’obsolescence. Dans le cadre de cette étude de cas, une trentaine d’entrevues semi-dirigées a été réalisée avec des usagers et réparateurs de produits électroniques en vue de documenter les différentes sous-étapes de la phase d’usage d’un téléviseur. Sur la base des informations recueillies, l’objectif de cette thèse est de formuler des recommandations, à destination des autorités politiques, qui pourront permettre une minimisation des impacts environnementaux liés à la phase d’usage des appareils électroniques. Les résultats ont permis de mettre en évidence, via le rôle et le statut singulier occupé par le téléviseur dans les foyers, les comportements de l’usager contribuant à augmenter l’empreinte écologique associée à la phase d’usage. L’acquisition de nombreux biens électroniques et non électroniques suite à l’achat du téléviseur, ses multiples fonctionnalités le rapprochant de celles de l’ordinateur et des tablettes, ainsi que la fin de vie prématurée de produits fonctionnels, mais obsolètes d’un point de vue technologique, font partie des résultats de cette recherche. En lien avec ces constats, cette étude propose des instruments de politique environnementale, dont l’affichage de la durée de vie des équipements électroniques, destinés à aider le consommateur à réaliser des choix plus éclairés au moment de l’achat. D’autres orientations, telles que la possibilité d’évoluer vers une réglementation horizontale, c’est-à-dire un cadre législatif qui ne se basera plus sur le produit individuel, mais sur l’ensemble des appareils ayant des fonctionnalités similaires, sont exposées. Par ailleurs, cette recherche explore certains leviers pouvant minimiser le phénomène de fin de vie prématurée des appareils électroniques, tels que l’envoi de biens obsolètes et fonctionnels des pays développés vers ceux en développement pour permettre leur réutilisation et la tendance du Do-It- Yourself dans la réparation des produits électroniques.Given its high environmental impact, Waste Electrical and Electronic Equipment (WEEE) has become a major problem for developed countries. The growing consumption of electronic products, whose useful lifespan has decreased over the years, has led to an increasing production of WEEE. In response, the European Union has adopted in 2003 the Extended Producer Responsibility (EPR). This environmental policy tool holds legally responsible manufacturers for the implementation and financing of the e-waste stewardship program. While the ERP focuses mainly on the environmentally sound disposal of waste from electric and electronic equipment, this instrument does not prevent or even reduce the growing amounts of e-waste discarded by households. This situation is particularly worrying, since the environmental benefits achieved with the implementation of the ERP are no longer efficient considering the continuous increase of electronic goods’ consumption in the world. In light of this issue, the present thesis examines the practices of users during the consumption phase of electronic appliances (also referred to as the use phase). This stage of the products’ lifecycle includes purchase, use, repair and disposal of a good. To conduct this research, a qualitative approach by means of a case study was used. The selected case is the television, which illustrates many issues related to the use phase of electronic devices, such as frequent launch of new models in the market, low purchase price compared to the cost of repair and the influence of trends on the consumer’s choices. These factors may cause the premature replacement of electronic products and, therefore, lead to their premature end-of-life, which materialize into different types of obsolescence. In the context of this case study, around thirty semi-structured interviews were conducted with users and repairers of electronic equipment in order to document the different sub-stages of the television’s use phase. Based on collected data, the main objective of this thesis is to provide recommendations to political authorities, which could enable the minimisation of environmental impacts related to the use phase of electronic appliances. The results highlight, via the role and singular status occupied by the television, the user’s behaviour which helps increase the environmental footprint of the use phase. The multiple purchases of electronic and non-electronic goods following the television’s acquisition, its many features that are similar to those of the computers or tablets, and the premature disposal of functional but technologically obsolete devices, are among the main findings of the study. In respect of these observations, this study proposes environmental policy instruments, like an environmental labelling of the electronic products’ lifespan, which aim at supporting a more informed consumer choice. Other orientations, such as the opportunity to adopt a horizontal policy, which is a legal framework that would no longer focus on the individual product, but rather on all appliances with similar functions, are exposed. In addition, this research explores some levers that could minimize the phenomenon of premature end-of-life of electronic devices, including the exportation of obsolete and functional goods from developed to developing countries to enable their reuse and the trend of Do-It-Yourself for their repair

Perspectives sur le statut des équipements électroniques à Montréal = Perspectives on the Status of Electronic Equipment in Montreal

"The [...] anthology responds to the ever-increasing amount of electronic equipment that is perceived as obsolete, valueless or disposable. Contributors from diverse disciplines including ecology, waste management, technology activism and contemporary art bring their expertise to bear on the consumption, use, obsolescence, disposal and repair and re-use of electronic equipment. Perspectives’ hybrid approach to these topics will be of interest to both general and specialized readers negotiating the cultural, environmental and social impacts of contemporary technology. Essays, projects and resource materials highlight approaches and practices that question consumption patterns and propose alternative approaches to using technology. Case studies and local contexts from Montreal Quebec are related to issues and initiatives across industrialized societies." -- Publisher's website

Solvent viscosity dependence for enzymatic reactions

A mechanism for relationship of solvent viscosity with reaction rate constant at enzyme action is suggested. It is based on fluctuations of electric field in enzyme active site produced by thermally equilibrium rocking (cranckshaft motion) of the rigid plane (in which the dipole moment $\approx 3.6 D$ lies) of a favourably located and oriented peptide group (or may be a few of them). Thus the rocking of the plane leads to fluctuations of the electric field of the dipole moment. These fluctuations can interact with the reaction coordinate because the latter in its turn has transition dipole moment due to separation of charges at movement of the reacting system along it. The rocking of the plane of the peptide group is sensitive to the microviscosity of its environment in protein interior and the latter is a function of the solvent viscosity. Thus we obtain an additional factor of interrelationship for these characteristics with the reaction rate constant. We argue that due to the properties of the cranckshaft motion the frequency spectrum of the electric field fluctuations has a sharp resonance peak at some frequency and the corresponding Fourier mode can be approximated as oscillations. We employ a known result from the theory of thermally activated escape with periodic driving to obtain the reaction rate constant and argue that it yields reliable description of the preexponent where the dependence on solvent viscosity manifests itself. The suggested mechanism is shown to grasp the main feature of this dependence known from the experiment and satisfactorily yields the upper limit of the fractional index of a power in it.Comment: 36 LaTex pages, 9 Eps figures, final versio

L’obsolescence des produits électroniques : des responsabilités partagées

La diminution de la durée de vie des produits électroniques est à l’origine de nombreux débats. Le fabricant a traditionnellement été désigné comme le principal responsable de ce phénomène, alors que l’usager est généralement considéré comme une victime. Bien que le fait soit peu reconnu, les autorités politiques exercent également une influence sur la pérennité des biens par le biais des stratégies qu’elles adoptent et des règlements qu’elles instaurent. À partir d’une analyse critique de la littérature sur ce thème, le présent article a pour objectif de jeter un nouveau regard sur l’obsolescence en discutant des responsabilités souvent ambiguës de ces trois acteurs qui, à différents niveaux, influencent la durée de vie des appareils électroniques. Cet article révèle que le cadre législatif européen, visant principalement les fabricants, offre des résultats mitigés pour lutter contre l’obsolescence des équipements électroniques. Sur la base de ce constat, les autorités politiques devraient également reconnaître l’influence de l’usager dans la diminution de la durée de vie des produits électroniques en vue d’instaurer des outils de politique environnementale permettant une gestion plus durable et efficace de ce type de biens. À cette fin, l’affichage environnemental de la durée de vie est explorée dans le but de mieux informer l’usager, à l’achat, de la durée de vie des appareils électroniques, et potentiellement minimiser l’obsolescence.The decrease in the lifespan of electronic products is the source of many debates. The manufacturer has traditionally been designated as the main cause of the decrease in the lifespan of electronic devices, while the consumer is usually considered as a victim. Although it is little known, political authorities have also an influence on the goods durability regarding the strategies they choose and the regulations they establish. Based on a critical analysis of literature, the present article aims at bringing a new perspective on obsolescence by discussing the ambiguous responsibilities of these three actors who, at different levels, influence the lifespan of electronic appliances. This article reveals that the current legal framework first aims at the manufacturers, but offers mitigated results to take concrete measures against obsolescence. In the view of this finding, political authorities should also recognize the influence of user in the decrease in product lifetimes in order to introduce environmental policy instruments to tend towards sustainable management of electronic equipment. To this end, the environmental labelling in product lifetimes is explored to better inform the user, at the time of purchase, on the electronic device lifespan and potentially minimize obsolescence

Helix motion in protein C12A-p8MTCP1: Comparison of molecular dynamics simulations and multifield NMR relaxation data

International audienceThe human p8(MTCP1) protein is constituted by an original disulfide bridged alpha-hairpin motif, and a third hydrophilic helix that appeared mobile and independent in NMR analysis. To get atomic scale description of the possible motions involved, a 12-ns molecular dynamics simulation of the C12A-p8(MTCP1) mutated protein and 10 400-ps simulations were performed in explicit water at 298 K. Analyses of the essential dynamics subspace and of the time-evolution of secondary structures indicate large displacements and internal motions of the third helix. Simulated order parameters, S,(2) are consistent to those obtained from (15)N-NMR relaxation data recorded at five different magnetic fields (proton resonance frequencies: 400, 500, 600, 700, and 800 MHz). The simulations show a fairly rigid alpha-hairpin motif with only very small local conformational changes, although the loop between helices undergoes significant correlated motions. The displacements and internal motions of the third helix can be essentially accounted for by alpha-helical to 3(10)-helical transitions near its N-terminus and by a hinge-bending motion near glycine 52. The loss of the alpha-helical conformation for a large part of the third helix during about 25% of the simulation time supports the possible occurrence of a slow motion as suggested by previous analyses of the (3)J(NH-H(alpha)) coupling constant values and of the proton-deuterium NH exchange kinetics

Rapid determination of protein solubility and stability conditions for NMR studies using incomplete factorial design

International audienceSample preparation constitutes a crucial and limiting step in structural studies of proteins by NMR. The determination of the solubility and stability (SAS) conditions of biomolecules at millimolar concentrations stays today empirical and hence time- and material-consuming. Only few studies have been recently done in this field and they have highlighted the interest of using crystallogenesis tools to optimise sample conditions. In this study, we have adapted a method based on incomplete factorial design and making use of crystallisation plates to quantify the influence of physico-chemical parameters such as buffer pH and salts on protein SAS. A description of the experimental set up and an evaluation of the method are given by case studies on two functional domains from the bacterial regulatory protein LicT as well as two other proteins. Using this method, we could rapidly determine optimised conditions for extracting soluble proteins from bacterial cells and for preparing purified protein samples sufficiently concentrated and stable for NMR characterisation. The drastic reduction in the time and number of experiments required for searching protein SAS conditions makes this method particularly well-adapted for a systematic investigation on a large range of physico-chemical parameters

Structure refinement of flexible proteins using dipolar couplings: application to the protein p8MTCP1

International audienceThe present study deals with the relevance of using mobility-averaged dipolar couplings for the structure refinement of flexible proteins. The 68-residue protein p8MTCP1 has been chosen as model for this study. Its solution state consists mainly of three alpha-helices. The two N-terminal helices are strapped in a well-determined alpha-hairpin, whereas, due to an intrinsic mobility, the position of the third helix is less well defined in the NMR structure. To further characterize the degrees of freedom of this helix, we have measured the dipolar coupling constants in the backbone of p8MTCP1 in a bicellar medium. We show here that including D(dip)HN dipolar couplings in the structure calculation protocol improves the structure of the alpha-hairpin but not the positioning of the third helix. This is due to the motional averaging of the dipolar couplings measured in the last helix. Performing two calculations with different force constants for the dipolar restraints highlights the inconstancy of these mobility-averaged dipolar couplings. Alternatively, prior to any structure calculations, comparing the values of the dipolar couplings measured in helix III to values back-calculated from an ideal helix demonstrates that they are atypical for a helix. This can be partly attributed to mobility effects since the inclusion of the 15N relaxation derived order parameter allows for a better fit

Low concentration of a Gd-chelate increases the signal-to-noise ratio in fast pulsing BEST experiments

International audienc