Assessment of biogas potential hazards

Biogas produced from anaerobic fermentation of organic substances represents an alternative renewable energy source. Its utilization would contribute to substantial reduction of the solid waste volume in land-filling and incineration. Biogas so produced could be utilized on site or it could be injected into the natural gas distribution network. Microbiological and chemical compositions of different biogas types were determined in order to conduct qualitative and quantitative risk assessments of the potential health hazards associated with biogas use for cooking. Biogas types that could be allowed for injection in the natural gas pipelines were listed with recommendations, while outlining the European biogas injection policy. Results indicated that the injection of the processed biogas in the distribution network did not present any additional chemical or microbiological risk to consumers when compared to natural gas, provided that the biogas resulted from the fermentation of non-dangerous waste. However, since this study did not examine the microbiological and chemical composition of biogas originating from wastewater sludges and/or industrial wastes, the injection of this type of biogas into the gas distribution network should not be allowed unless a similar risk evaluation study is conducted for each case.     

Fast resolution of incremental forming processes by the Multi-Mesh method. Application to cogging

A Multi-Mesh Multi-Physics (MMMP) method is developed to reduce the very long computational time required for simulating incremental forming processes such as cogging or ring rolling. It consists in using several finite element meshes on the same domain to solve the different physics of the problem. A reference mesh is used to accurately store the results and history variables, while the different computational meshes are optimized to solve each physic of the problem. The MMMP algorithm consists in two main key-steps: the generation of the different unstructured meshes and the data transfer between the meshes. The accuracy of the method is supported by using meshes that are embedded by nodes. The method is applied to the simulation of the cogging metal forming process for which it shows as accurate and more than ten times faster than the standard method with a single mesh.     

Evaluation of the gastrotoxicity of anti-inflammatory drugs: contribution of general registries of digestive endoscopy

The evaluation of the rate of gastroduodenal toxicity of anti inflammatory drugs is a difficult problem. We tried to analyse that question by studying the general endoscopic registers of the Gastro-Enterologic department of the hospital. This retrospective study concerns 2,945 endoscopies performed during the year 1988 and 1992 randomly chosen among the last 5 years. 992 results show injuries suggestive of non steroidal anti inflammatory drugs (NSAID) toxicity, however only in 65 cases the potential role of an anti inflammatory drug is mentioned: 36 men and 29 women, mean age: 50.6 +/- 19.6 years. Concerning the drugs, only the pharmacological classes they belong to are mentioned except for Aspirin. Acetyl salicylate acid 7 cases, NSAIDS 36 and Steroids 22. In the drug group 63% of injuries are located to the stomach (ulcers 13%, gastritis 50%), 37% to the duodenum (19% ulcers, 18% duodenitis). Compared to the groups with the same kind of injuries, but without any mention of drugs, there are no statistical difference in the proportion of ulcers. Aging and sex are not influent in our results on the genesis of drug induced ulcers. These results must be discussed because a lot of datas are missing in the registers and so the number of patients taking drugs is probably underestimated. This means that unless a prospective study is held with someone enquiring for all the risk factors, the study of the general endoscopic registers is not a good way to estimate gastrointestinal damages due to drugs.     

Le traitement cognitivo-comportemental du trouble de panique: une recension critique des écrits.

Reviews the mainly English-language clinical research and some studies by the present authors on the use of cognitive and behavioral procedures to treat panic disorder. Controlled studies and noncontrolled studies are considered. Use of relaxation, respiratory control, and exposure is discussed. (English abstract) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Stabilisation électrique de films résistants en zinc pulvérisé

Zinc sputtered thin films show, after aging, an electric resistance of high fidelity versus the variations of electric field and temperature; fractionned sputtering introduces no disturbance in the evolution of electrical resistance. Data are in qualitative agreement with the consequences of Laville Saint Martin's theories.     

Contribution of mass spectrometry to the study of the Maillard reaction in food

The Maillard reaction or non-enzymatic browning corresponds to a set of reactions occurring between amines and carbonyl compounds, especially reducing sugars. The Maillard reaction is known to occur in heated, dried, or stored foods and in vivo in mammalian organisms. In food, the Maillard reaction is responsible for changes in colour, flavor, and nutritive value but also for the formation of stabilizing and mutagenic compounds. Because of the complexity of the Maillard reaction, mass spectrometry, coupled or not to separation techniques, is a key tool in this research area and we will review in this article the contribution of mass spectrometry to the understanding of this reaction. Different steps of Maillard reaction will be described and the importance and the role played by mass spectrometry will be highlighted. In addition, different approaches to investigate the Maillard reaction from the formation of Amadori products (early Maillard reaction product) to the flavor and melanoidin production will also be covered.     

Signal decay due to susceptibility-induced intravoxel dephasing on multiple air-filled cylinders: MRI simulations and experiments

OBJECTIVE: Characterization of magnetic susceptibility artefacts with assessment of the gradient-echo signal decay function of echo time, pixel size, and object geometry in the case of air-filled cylinders embedded in water. MATERIALS AND METHODS: Experiments were performed with a 0.2 T magnet on a network of small interacting air-filled cylinders along with Magnetic resonance imaging (MRI) simulations integrating intravoxel dephasing. Signal decay over echo time was assessed at different pixel sizes on real and simulated images. The effects of radius, distance between cylinders and main magnetic field were studied using simulation. RESULTS: Signal loss was greater as echo time or pixel size increased. Voxel signal decay was not exponential but was weighted by sinus cardinalis functions integrating echo time, pixel size and field inhomogeneities which depended on main magnetic field strength and geometric configuration of the object. Simulation was able to model signal decay, even for a complex object constituted of several cylinders. The specific experimental signal modulation we observed was thus reproduced and explained by simulation. CONCLUSION: The quantitative signal decay approach at 0.2 T can be used in characterization studies in the case of locally regular air/water interfaces as the signal depends on object size relative to pixel size and is relevant to the geometric configuration. Moreover, the good concordance between simulation and experiments should lead to further studies of magnetic susceptibility effects with other objects such as networks of spheres. MRI simulation is thus a potential tool for molecular and porous media imaging.     

A formal approach to AADL model-based software engineering

International Journal on Software Tools for Technology Transfer - Formal methods have become a recommended practice in safety-critical software engineering. To be formally verified, a system should...