Coupling continuous damage and debris fragmentation for energy absorption prediction by cfrp structures during crushing

Energy absorption during crushing is evaluated using a thermodynamic based continuum damage model inspired from the Matzenmiller–Lubliner–Taylors model. It was found that for crash-worthiness applications, it is necessary to couple the progressive ruin of the material to a representation of the matter openings and debris generation. Element kill technique (erosion) and/or cohesive elements are efficient but not predictive. A technique switching finite elements into discrete particles at rupture is used to create debris and accumulated mater during the crushing of the structure. Switching criteria are evaluated using the contribution of the different ruin modes in the damage evolution, energy absorption, and reaction force generation

Could conservative iron chelation lead to neuroprotection in amyotrophic lateral sclerosis?

Iron accumulation has been observed in mouse models and both sporadic and familial forms of Amyotrophic lateral sclerosis. Iron chelation could reduce iron accumulation and the related excess of oxidative stress in the motor pathways. However, classical iron chelation would induce systemic iron depletion. We assess the safety and efficacy of conservative iron chelation (i.e. chelation with low risk of iron depletion) in a murine preclinical model and pilot clinical trial. In Sod1G86R mice, deferiprone increased the mean life span as compared with placebo. The safety was good, without anemia after 12 months of deferiprone in the 23 ALS patients enrolled in the clinical trial. The decreases in the ALS Functional Rating Scale and the body mass index (BMI) were significantly smaller for the first 3 months of deferiprone treatment (30 mg/kg/day) than for the first treatment-free period. Iron levels in the cervical spinal cord, medulla oblongata and motor cortex (according to MRI), as well as cerebrospinal fluid levels of oxidative stress and neurofilament light chains were lower after deferiprone treatment. Our observation leads to the hypothesis that moderate iron chelation regimen that avoids changes in systemic iron levels may constitute a novel therapeutic modality of neuroprotection for ALS

Le développement socialement durable

International audienc

Vers l’électronique imprimée à l’IMS Bordeaux - plateforme technologique TAMIS (Technologies Alternatives aux MIcrosystèmes Silicium)

L’électronique imprimée « Printed Electronics » prend de nos jours de plus en plus d’importance. Parmi les techniques d’impression, les plus répandues sont la sérigraphie, le jet d’encre et la flexographie, cette dernière étant une technique roll to roll (R2R) permettant d’augmenter la vitesse d’impression. Nous disposons au niveau de la plateforme de technologie TAMIS (Technologie Alternative aux Microsystèmes) hébergée au Laboratoire IMS de Bordeaux des deux premières techniques d’impression dédiées à la recherche et à l’enseignement. La sérigraphie est la plus utilisée de par sa simplicité, sa flexibilité et son bas coût et des réalisations sont décrites (jauges de déformation, antennes patchs). Ces évolutions vers l’électronique imprimée pour des composants ou systèmes ou pour l’assemblage sont illustrées chaque année auprès d’une soixantaine d’étudiants issus des filières électroniques

Strategies for gas sensing by means of surface acoustic wave sensors

Support IFCPAR/CEFIPRAInternational audienceAs previously presented, Surface Acoustic Wave or SAW-based devices are of great interest for gas sensing applications. The major advantages related to the transducer itself, such as high sensitivity and real-time capability, are emphasized by appropriate strategies in defining the sensitive coating, which plays a major role in terms of sensitivity, selectivity and stability of the resulting device, including reversibility.In order to illustrate these issues, different strategies involved in various applications studied at IMS labs are presented. In particular, we will focus on grafted fluoropolyol matrices used for the detection of organophosphorous compounds, as well as on structured thin-film materials emphasized for their high effective surface among other advantages, such as mesoporous silicon dioxide or titania. We will also introduce an increasing interest for carbonated materials such as nanotubes or graphene which could lead to unexpected sensitivities, for SAW microsensors and more generally for microtransducers based on high frequency resonant phenomenon

Ultrasensitive Acoustic transducer: Application for gas and bio-sensing

International audienc

Microwave-based microsensor printed on film for the monitoring of environmental or health-related chemical compounds

National audienceThe need for miniature sensors, integrated in all environments, highly selective and sensitive, with low cost and low power consumption, is growing more each year, due to the modernization and increasing global industrialization, which increase environmental and health pollution. This pollution concerns 7 million deaths in 2012, according to World Health Organization (WHO). It is known as a source of irritation, decreased lung capacity and odors. Some of these pollutants are considered carcinogenic, among them volatile organic compounds (VOCs) represent an issue as target compounds. In this context and to respond to this problem, we propose the real-time monitoring and quantification sensor for toxic gas, by combining an electromagnetic transduction resonator with a chemical sensitive layer of carbonaceous material in the frequency band from 0.5 GHz to 6 GHz. This platform is suitable for the Internet of Things and embedded systems, which open revolutionary perspectives to the proliferation of sensing and control sites with communicating wireless sensor networks