Compaction behavior of out-of-autoclave prepreg materials

The main challenges with composite parts manufacturing are related to the curing means, mainly autoclaves, the length of their cycles and their operating costs. In order to decrease this dependency, out of autoclave materials have been considered as a solution for high production rate parts such as spars, flaps, etc… However, most out-of-autoclave process do not possess the same maturity as their counterpart, especially concerning part quality1. Some pre-cure processes such as compaction and ply lay-up are usually less of a concern for autoclave manufacturing: the pressure applied during the cycle participates to reduce the potential defects (porosity caused by a poor quality lay-up, bad compaction, entrapped air or humidity…). For out-of-autoclave parts, those are crucial steps which may have many consequences on the final quality of the laminate2. In order to avoid this quality loss, those steps must be well understood

Modélisation des cinétiques de polymérisation de résines destinées à la fabrication Hors Autoclave

The main challenges with composite parts manufacturing are related to the curing means, mainly autoclaves, the length of their cycles and their operating costs. In order to decrease this dependency, out of autoclave materials have been considered as a solution for high production rate parts such as spars, flaps, etc… However, most out-of-autoclave process do not possess the same maturity as their counterpart, especially concerning part quality 1. Three out-of-Autoclave prepreg materials were considered for this study, each one possessing different curing temperatures: A (180°C), B (125°C) and C (132°C). Those materials have also different chemical compositions, although all three have been designed for out-of-autoclave composite part manufacturing (primary and secondary structures). The interest of our study is to understand and compare polymerization mechanisms of each matrix, by defining each time a predictive model close to experimental values of the curing of those epoxy/amine systems 2

La formación del capital social en los ejidos mexicanos. Decisiones sobre las tierras tras el artículo 27 de la reforma constitucional

The Mexican ejidos are complex land-based structures developed by the post-revolutionary state formation (1915-1992). The success of some ejidos was based on trust ties. With the economic liberalization of the country and the changes to the national legal system in the early 1990s (specifically Article 27 reform in 1992), the state structures that ran the ejidos were reorganized, and individual land tenure strategies reappeared. In La Antigua (Veracruz), a majority of the ejidatarios (71%) reacted to this situation by adopting the dominio pleno (full domain) land tenure regime. In analyzing these features and their connections with diachronic social capital, this paper discusses the role of the national structures and institutions across generations and the destruction of trust in the ejidos. Specific ejido histories help to compare pre-ejido land strategies with the post-Article 27 reform strategies in effect today. It will be concluded that inefficient coordination of the micro, meso and macro levels of the state creates distrust and encourages individual action.Los ejidos mexicanos son complejas estructuras de propiedad colectiva de la tierra, desarrolladas por el Estado post-revolucionario (1915-1992). El éxito de algunos de estos ejidos ha estado basado en los lazos de confianza entre los campesinos. A principios de los noventa, la liberalización económica y la reforma del Artículo 27 Constitucional en 1992, favorecieron una reorganización de las estructuras del Estado que dirigían el ejido y la reaparición de estrategias individuales de tenencia de la tierra. El ejido de La Antigua (Veracruz) presenta la particularidad de que un 71% de los ejidatarios reaccionaron antes este escenario adoptando el régimen de dominio pleno de tenencia de la tierra. Este trabajo tiene como objetivo analizar la conexión entre esta situación y i) el capital social diacrónico existente en este ejido y ii) el papel de las estructuras e instituciones nacionales en la generación o destrucción de la confianza en los ejidos. El análisis de historias particulares de este ejido ayuda a comparar las estrategias anteriores a la formación ejidal con las devenidas tras la reforma del Artículo 27. Se llega a la conclusión de que la ineficiente coordinación de los niveles micro, meso y macro del Estado, ha generado desconfianza y hecho que los ejidatarios actúen de manera individualista

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Modélisation des cinétiques de polymérisation de résines destinées à la fabrication Hors Autoclave

International audienceThe main challenges with composite parts manufacturing are related to the curing means, mainly autoclaves, the length of their cycles and their operating costs. In order to decrease this dependency, out of autoclave materials have been considered as a solution for high production rate parts such as spars, flaps, etc… However, most out-of-autoclave process do not possess the same maturity as their counterpart, especially concerning part quality 1. Three out-of-Autoclave prepreg materials were considered for this study, each one possessing different curing temperatures: A (180°C), B (125°C) and C (132°C). Those materials have also different chemical compositions, although all three have been designed for out-of-autoclave composite part manufacturing (primary and secondary structures). The interest of our study is to understand and compare polymerization mechanisms of each matrix, by defining each time a predictive model close to experimental values of the curing of those epoxy/amine systems 2

Compaction Behavior Of Out-of-Autoclave Prepreg Materials

International audienceThe main challenges with composite parts manufacturing are related to the curing means, mainly autoclaves, the length of their cycles and their operating costs. In order to decrease this dependency, out of autoclave materials have been considered as a solution for high production rate parts such as spars, flaps, etc… However, most out-of-autoclave process do not possess the same maturity as their counterpart, especially concerning part quality1. Some pre-cure processes such as compaction and ply lay-up are usually less of a concern for autoclave manufacturing: the pressure applied during the cycle participates to reduce the potential defects (porosity caused by a poor quality lay-up, bad compaction, entrapped air or humidity…). For out-of-autoclave parts, those are crucial steps which may have many consequences on the final quality of the laminate2. In order to avoid this quality loss, those steps must be well understood