Biomass gasification in a fluidized bed reactor: effect of temperature on properties and oxidative reactivity of chars

Introduction: Biomass gasification is a promising alternative to fossil fuels for the synthesis of highly energetic products via Fischer-Tropsch or methanation processes. It is a thermochemical conversion occurring at high temperatures with many simultaneous reactions. For temperatures above 350°C, biomass undergoes a thermal decomposition called pyrolysis which leads to the formation of volatile products either condensable (steam and tars) or incondensable (H2, CO, CO2, CH4 and C2Hx) and a solid residue called char [1]. Then, the char reacts with steam and carbon dioxide at temperatures greater than 700°C to produce syngas. These transformations are endothermic. Therefore, a contribution of energy is required to maintain the temperature and the different reactions. One of the most encouraging and advanced technology is dual fluidized beds [2]. Its principle relies on the circulation of a media (sand, olivine or catalyst particles) which acts as a heat carrier between an endothermic reactor, where biomass gasification produces syngas, and an exothermic reactor where combustion of a part of the char from the gasification of biomass produces heat. Therefore, it is of importance to carefully understand the effect of operating conditions on char structure and composition which are directly related to its reactivity in combustion and steam gasification. During pyrolysis of biomass, many changes occur in the solid structure including (1) the loss of functional groups on the carbon surface, (2) ordering of the carbon microstructure to tend to a graphitic crystalline form, (3) the formation of pores which directly influence the surface area, (4) the modification in ash content and its distribution that affect the catalytic activity of chars. Together, these changes are responsible for the steam gasification and combustion reactivity of the chars. Please click Additional Files below to see the full abstract

Towards solving social and technical problems in open source software ecosystems : using cause-and-effect analysis to disentangle the causes of complex problems

Managing large-scale development projects in open source software ecosystems involves dealing with an array of technical and social problems. To disentangle the causes of such problems, we interviewed experts and performed a cause-and-effect analysis. Our findings demonstrate that loss of contributors is the most important social problem, while poor code quality is the most important technical problem, and that both problems result from complex socio-technical interrelations of causes. Our approach suggests that cause-and-effect analysis can help to better understand problems in open source software ecosystems

Responsible Conduct of Research in Research-Creation: Moving into Uncharted Terrain

Responsible conduct of research (RCR) is ubiquitous, and present in most areas of research. One area that has received little attention is Research-Creation (RC): • an emergent eld at the interface of academic research and creative activities • in Quebec, Canada, RC is de ned as “research activities or approaches that foster the creation or interpretation/ performance of literary or artistic works of all types” Researcher-Creators – who are at the same time researchers and practising artists, musicians, or designers – may be faced with very di erent issues or challenges from colleagues in the rest of academia. • How do researcher-creators reconcile their dual obligations to creation and to research? • Are the usual research ethics guidelines (e.g., TCPS2, ICH relevant and how do they apply? • How do the creative/artistic dimensions of research a ect evaluations by grant committees and REBs? To better understand how RCR issues are articulated in the very heterogeneous RC community, we combine here results from a literature review and an international survey on RCR in RC.FRQ Action concerté

HBM4EU chromates study - Overall results and recommendations for the biomonitoring of occupational exposure to hexavalent chromium

Exposure to hexavalent chromium [Cr(VI)] may occur in several occupational activities, e.g., welding, Cr(VI) electroplating and other surface treatment processes. The aim of this study was to provide EU relevant data on occupational Cr(VI) exposure to support the regulatory risk assessment and decision-making. In addition, the capability and validity of different biomarkers for the assessment of Cr(VI) exposure were evaluated. The study involved nine European countries and involved 399 workers in different industry sectors with exposures to Cr(VI) such as welding, bath plating, applying or removing paint and other tasks. We also studied 203 controls to establish a background in workers with no direct exposure to Cr(VI). We applied a cross-sectional study design and used chromium in urine as the primary biomonitoring method for Cr(VI) exposure. Additionally, we studied the use of red blood cells (RBC) and exhaled breath condensate (EBC) for biomonitoring of exposure to Cr(VI). Personal measurements were used to study exposure to inhalable and respirable Cr(VI) by personal air sampling. Dermal exposure was studied by taking hand wipe samples. The highest internal exposures were observed in the use of Cr(VI) in electrolytic bath plating. In stainless steel welding the internal Cr exposure was clearly lower when compared to plating activities. We observed a high correlation between chromium urinary levels and air Cr(VI) or dermal total Cr exposure. Urinary chromium showed its value as a first approach for the assessment of total, internal exposure. Correlations between urinary chromium , Cr(VI) in EBC and Cr in RBC were low, probably due to differences in kinetics and indicating that these biomonitoring approaches may not be interchangeable but rather complementary. This study showed that occupational biomonitoring studies can be conducted successfully by multi-national collaboration and provide relevant information to support policy actions aiming to reduce occupational expo-sure to chemicals

La base sous-marine de Bordeaux, sous le béton la culture

Build during the German occupation, the submarine base of Bordeaux active during hardly more than a year still crystallizes the painful memories of the dark hours of the « Port de la Lune ». Nevertheless, the bunker attracts artists, film-makers, visual artists and musicians fascinated by the spirit of the place since the 1960’s. Institutionalized at the beginning of 1990’s, the submarine base became a space dedicated to the yachting before contemporary art at the beginning of the XXIth century. Nowadays at the heart of the project of redevelopment of the wet docks in the urban area of Bacalan, the submarine base questions and intrigues its visitors on its past, but also – and especially – on its future

Migrating a software factory to design thinking - paying attention to people and mindsets

Design Thinking (DT) has found its way into software engineering, promising better requirements elicitation, customer relations, and cohesion within the development team. However, does DT really live up to its promise? This paper reports on the migration of Proaction Technologies towards DT, and empirically evaluates the new DT process through interviews with employees and clients. While DT is able to live up to its promises, its adoption entails paying close attention to the people involved and their mindsets

The human occupation of the northwestern Pyrenees in the Late Glacial: New data from the Arudy basin, lower Ossau valley

International audienceExcavated since the 1860s, the Arudy basin has yielded a number of rich Magdalenian sites that enable us to address the question of the human reoccupation of the lower Pyrenean valleys at the end of the Last Glacial Maximum. Until the 1990s, it was considered that at Arudy this reoccupation started ca. 16,000 cal BP in the Middle Magdalenian and continued into the Upper Magdalenian until ca. 14,000 cal BP. However, since the mid-2000 s, this picture has been modified through a series of new analyses, excavations (caves of Laa 2 and Tastet), 14C dates and reassessment of ancient collections. Evidence of human occupation ca. 20,000–19,000 cal BP, although limited, has been identified at Laa 2 and Tastet, consistent with numerous data obtained at Pyrenean scale showing a deglaciation of the north Pyrenean foothills as early as the end of the global LGM. The number of sites with evidence of Magdalenian has increased, showing that human presence in the basin was more intensive than previously thought. The Middle and Upper Magdalenian occupations have been redated to at least 18,000–17,500 cal BP to 15,000–14,500 cal BP, with the transition between the two phases probably occurring ca. 16,600–16,200 cal BP. The faunal records of these sites document an emphasis on horse hunting, which is not common in the northern Pyrenees, but also witness an evolution over time in the range of species hunted. Furthermore, the Pyrenean affinities of the Arudy groups and their relations with neighboring regions, such as Spain and the northern part of the Aquitaine basin, can be addressed through new evidence: in particular lithic and osseous raw materials and specific types of projectile tips. These results significantly change our view of the nature, rhythm and chronology of the Late Glacial settlement in this area

Papillary muscle head repositioning for commissural prolapse in degenerative mitral valve disease†

Cardiolog