Development of HiCapt+

It is now well known that “first generation” MEA based post-combustion carbon capture processes require high energy consumption and have problems with solvent degradation due to oxygen. Nevertheless, it is the only available process for first industrial units. That is why IFP Energies nouvelles, has developed HiCapt+ process, based on a conventional MEA solvent but using high performance oxidative inhibitors and higher amine concentration. These oxidative inhibitors enable HiCapt+’s process to use high solvent concentrations without corrosion or degradation problems and lead to reduction of the regeneration energy demand due to solvent flow rate reduction. Moreover, the huge reduction of solvent degradation rate avoids the difficult management of reclaiming unit, as well as avoiding high concentration of light degradation products in the treated flue gas, like NH3

Enzymatic hydrolysis at high lignocellulosic content: Optimization of the mixing system geometry and of a fed-batch strategy to increase glucose concentration

Working at high values of lignocellulosic Dry Matter (DM), as wheat straw, increases the reaction medium viscosity, making the mixing inefficient with the traditional agitators. Batch and fed-batch tests were conducted using different impellers: i) inclined blades, ii) marine impeller, iii) anchor, iv) paravisc and v) double helical impeller. Inclined blades appeared an inadequate device for batch and fed-batch tests. On contrary, double helical impellers and anchor gave optimal performances. An alternative to improve the reactor\u2019s rheology is the modification of the feeding strategy. A particular fed-batch strategy allowed keeping low the reaction medium viscosity by a gradual increasing of the DM content in the reactor. In this way, three main benefits were achieved: i) a very good performances in terms of glucose concentration (85 g/L), ii) a strong reduction of the energetic consumption compared to batch test and iii) the adoption of a simple mixing devise

Enzymatic hydrolysis at high dry matter content: The influence of the substrates\u2019 physical properties and of loading strategies on mixing and energetic consumption

The present work investigates the impact of the physical properties and loading strategies of wheat straw and miscanthus on enzymatic hydrolysis at high DM concentration. Three parameters have been chosen to evaluate the enzymatic hydrolysis performance: (i) the mixing time, (ii) the energetic mixing consumption and (iii) the glucose concentration. It was demonstrated that the hydrolysis of miscanthus is easy to perform and has low viscosity. On the contrary, the higher porosity grade of wheat straw than miscanthus (73% against 52%) contributed to have a very high viscosity at 20% w/w DM. The development of a fed-batch strategy allowed the reduction of viscosity inducing the energetic consumption lowering from 30 kJ to 10 kJ. It has been also proven that the miscanthus addition in wheat straw achieved to decrease mixing energy consumption at 5\u20138 kJ, when it represented more than 30% of the total mass of the reaction medium

10 ans : Numéro anniversaire

Quelles sont les dynamiques constitutives des études urbaines en France ? Quels sont les questionnements, les approches méthodologiques et les références théoriques qui caractérisent aujourd’hui ce champ d’étude ? Quels en sont les angles morts ? Comment ce champ s’articule-t-il avec les débats qui animent communauté internationale, et particulièrement anglophone ? Ce numéro Hors-série, conçu pour le dixième anniversaire de la revue Métropoles, propose de revenir sur les études urbaines en France. Il ouvre également des pistes de recherche et suggère des terrains peu couverts pour qui s’intéresse aux phénomènes urbains et métropolitains. Au-delà de son propos liminaire, cette introduction présente la structuration du numéro, autour de quatre grands axes. Le premier ensemble d’articles situe la trajectoire de Métropoles au regard de l’évolution de ses ambitions et de ses contenus, ainsi que du contexte éditorial. Le deuxième rassemble des enquêtes de terrain, qui interrogent collectivement les conditions d’une critique dans les études urbaines. La troisième partie du numéro s’attache aux enjeux de la métropolisation dans des villes du Sud, en explorant des terrains peu couverts jusque-là dans la revue. Enfin, plusieurs portraits clôturent ce numéro. Ils invitent à repenser les frontières disciplinaires et les interfaces avec le monde social et politique. What are the main features of urban studies in France? Which issues, methodological approaches and theoretical approaches constitute this field of study? What are the blind spots? How does this field contribute to international debates on urban studies?This special issue, for the tenth anniversary of the journal Métropoles, takes a look back at urban studies in France. It also opens new research perspectives and suggests promising fieldwork for those interested in urban and metropolitan phenomena.This introduction also presents the structuring of this special issue around four axes. The first set of articles locates the trajectory of Métropoles with regards to the evolution of its ambitions and contents, as well as editorial context. The second set of articles brings together scientific investigations, which collectively question the conditions of criticism in urban studies. The third part focuses on the issue of metropolization in cities in the South, exploring areas that have not yet been adequately covered in the journal. Finally, several portraits close this special issue. They invite the reader to reconsider disciplinary boundaries and interfaces between social and political worlds

Espace et rapports de domination

Dégagé de la plupart de ses contrepouvoirs depuis la fin des années 1980, le projet politique néolibéral et les inégalités qu’il renforce paraissent aujourd’hui sans remède. Est-il si difficile de ne pas céder à la résignation ou, pire, à l’indifférence ? Les outils pour identifier ces inégalités, les expliquer et les dénoncer ne manquent pas. La pensée critique connaît, en France comme ailleurs, un formidable renouveau. Dans toutes les disciplines des sciences sociales, l’apport de nos aînés est revisité et enrichi de nouvelles propositions pour se confronter aux injustices contemporaines, qui semblent rendues acceptables par des manipulations intellectuelles et des ficelles de plus en plus grossières. L’espace est, comme le temps et l’argent, un redoutable allié des dominants. Accaparé, exproprié, spolié, marchandisé, financiarisé, surveillé, refusé, l’espace se révèle être, à toutes les échelles et dans toutes ses configurations, une excellente clef de lecture de la situation des dominés. Confinement, relégation, enfermement en sont les modalités extrêmes, mais bien d’autres, plus subtiles et moins visibles, contribuent à pérenniser des rapports de force à ce point asymétriques qu’il n’est de meilleur terme pour les qualifier que celui de domination. Mais l’espace est aussi l’allié des dominés engagés dans des processus de résistance, de contestation ou de lutte contre l’ordre du capitalisme néolibéral. Dotés de ressources propres, les dominés construisent aussi des stratégies, individuelles ou collectives, qui prennent appui dans l’espace et peuvent faire de ce dernier une ressource pour se faire entendre ou se rendre visible. Dans un contexte académique mondial dominé par les travaux anglophones, en particulier ceux de la géographie radicale, cet ouvrage entend présenter la manière dont les chercheurs et chercheuses francophones travaillant sur les questions spatiales analysent les rapports sociaux de domination, qu’ils soient de classe, de race, de sexe, autant de rapports sociaux qui ont un fondement matériel. Plusieurs entrées thématiques sont explorées, qui renvoient à des champs de recherche bien identifiés : la question urbaine, les études sur le genre, le sexe, la sexualité et l’intersectionnalité, la question des migrations et celle des populations marginalisées et, enfin, l’environnement. Cet ouvrage témoigne donc de la grande vivacité des travaux francophones, tout en réaffirmant l’utilité de penser l’espace dans la critique sociale

Changes in Cannabis Consumption During the Global COVID-19 Lockdown: The International COVISTRESS Study

Introduction: COVID-19 lockdown measures have been sources of both potential stress and possible psychological and addiction complications. A lack of activity and isolation during lockdown are among the factors thought to be behind the growth in the use of psychoactive substances and worsening addictive behaviors. Previous studies on the pandemic have attested to an increase in alcohol consumption during lockdowns. Likewise, data suggest there has also been a rise in the use of cannabis, although it is unclear how this is affected by external factors. Our study used quantitative data collected from an international population to evaluate changes in cannabis consumption during the lockdown period between March and October, 2020. We also compared users and non-users of the drug in relation to: (1) socio-demographic differences, (2) emotional experiences, and (3) the information available and the degree of approval of lockdown measures. Methods: An online self-report questionnaire concerning the lockdown was widely disseminated around the globe. Data was collected on sociodemographics and how the rules imposed had influenced the use of cannabis and concerns about health, the economic impact of the measures and the approach taken by government(s). Results: One hundred eighty two respondents consumed cannabis before the lockdown vs. 199 thereafter. The mean cannabis consumption fell from 13 joints per week pre-lockdown to 9.75 after it (p < 0.001). Forty-nine respondents stopped using cannabis at all and 66 admitted to starting to do so. The cannabis users were: less satisfied with government measures; less worried about their health; more concerned about the impact of COVID-19 on the economy and their career; and more frightened of becoming infected in public areas. The risk factors for cannabis use were: age (OR = 0.96); concern for physical health (OR = 0.98); tobacco (OR = 1.1) and alcohol consumption during lockdown (OR = 1.1); the pre-lockdown anger level (OR = 1.01); and feelings of boredom during the restrictions (OR = 1.1). Conclusion: In a specific sub-population, the COVID-19 lockdown brought about either an end to the consumption of cannabis or new use of the drug. The main risk factors for cannabis use were: a lower age, co-addictions and high levels of emotions.publishedVersio