Science & Mathematics

In retreating faces, dilution of firedamp flowing out of the goaf area at the junction of face and retum roadway is problematic. Despite important flowrates and high CH4 drainage efficiencies, it has been observed that 2/3 of firedamp evacuated by the air stream concentrate in this particular place. So äs to progress in preventing such difficulties, it is necessary to better understand the repartition of gas fluxes in the goaf. This has obviously a benefit on firedamp drainage efficiency, but also on the choice of nitrogen injection points and flowrates in case of spontaneous combustion in the goaf. The use of a CFD code, PHOENICS, has allowed Simulation of circulation of three gases : air, CH4, and N2. Influence of the face dip on the repartition of CH4 patterns in the goaf area has been qualitatively demonstrated.

Rapid assessments of landslides (including other mass movements of rock, snow and ice) as well as human impacts were conducted by many organizations immediately following the 25 April 2015 M7.8 Gorkha earthquake and its aftershock sequence. In particular, a NASA-led satellite mapping campaign identified over 4,300 coseismic and post-seismic landslides throughout Nepal, largely concentrated in the “down-dropped northern tectonic block” well north of Kathmandu in the Greater Himalaya (Kargel et al., 2016). The Solukhumbu District lies at the eastern margin of this zone, near the epicenter of the 12 May 2015 M7.3 aftershock. Given the enormous cultural and economic value of the Khumbu region to Nepal, we conducted two post-monsoon ground assessments of geomorphic and structural damage in the fall of 2015, and a third ground assessment of rebuilding efforts in May, 2016. While landslides and other mass movements were not as extensive as those to the west, numerous landslides and slumps were identified, mostly on steep, convex-up, east-facing slopes where the dip of metamorphic foliation (Namche orthogneiss and related rocks) is towards the Dudh Kosi River channel. Also, building damage was more extensive where villages were located on terraces of unconsolidated sand and gravel perched above the Dudh Kosi River (Nakchun Village). The area upstream from Phakding experienced several co-seismic mass movements on steep slopes that had clearly failed before (previous temblors?), as evidenced by old vegetated slump blocks and steep, unstable hummocky terrain. Particularly hard-hit was the Sherpa village of Thame northwest of Namche Bazaar, constructed on unconsolidated, water-saturated glacial outwash between two lateral moraines at the mouth of the Thame Khola Valley. Aside from Thame, one is struck by the randomness of structural damage in many Sherpa villages, reflecting micro-ground conditions beneath buildings and the style and/or age of construction (dry-stacked fieldstone versus the use of mud or cement mortar, the presence of wire mesh or gabion bands/spacers within stone walls, etc.). Fresh valley-flank slumps and landslides were markedly less obvious further north (towards Everest) where wide glacial valleys exist, although evidence of large rock falls and other mass movements in the past is clearly present.

This article reports on a qualitative study in a materially deprived locality in northern England, which originally aimed to explore local residents' views of proposed changes to local health care provision. However, participants also quickly moved the research agenda onto widespread discussions of (mis)trust. Unlike much sociological literature that defines trust as operating on two levels (inter-personal and system-based), their narratives of trust were constructed on several inter-connected levels. We explore mistrust in local general practitioners (GPs) as a factor of mistrust of a number of local and national organizations and social systems, rather than solely related to the medical system. Widespread mistrust of ‘authority' was narrated through a shared history of disinvestment and loss of services in the locality and ‘broken promises' by a range of institutions, which precipitated feelings of social exclusion and disembeddedness

AIN thin films were grown by the Atomic Layer Epitaxy (ALE) technique employing AlCl3 and NH3 as precursors. A growth rate of 1.0 Å/cycle was obtained in experiments carried out at 500 °C. The films deposited onto soda lime glass substrates were polycrystalline exhibiting a strong preferred orientation in the [001] direction. X-ray Photoelectron Spectroscopy (XPS) measurements revealed that the films contained oxygen and chlorine as impurities.

Lors d'accidents industriels mettant en jeu des explosions, des incendies ou des émissions de produits toxiques ou inflammables dans l'environnement, les effets à prendre en compte s'expriment en termes d'impulsions de pression, de projections de débris, de flux thermiques et de rejets de produits toxiques dans l'air, les eaux et les sols. Dans sa première partie, le présent article présente les conclusions consécutives à l'analyse de différents types d'accidents survenus en France et met en évidence l'absence de connaissances suffisantes sur le déroulement d'explosions non confinées ou partiellement confinées et sur les modalités d'émissions de produits toxiques lors d'incendies. La prise en considération de ces accidents et de bases de données sur les accidents permettra aux autorités compétentes, aux industriels, aux assureurs et aux centres techniques intéressés par ces questions de partager leurs expériences. La seconde partie aborde la validation des logiciels commerciaux de calcul des conséquences. La comparaison des résultats de l'examen des logiciels CAMEO 3.0, CHARM 6.1, PHAST 3.0 et TRACE 2.5.4. utilisés pour définir tout ou partie des effets mentionnés plus haut a permis de mettre en évidence la nécessité d'un protocole d'évaluation. Pour un tel protocole sont à retenir : la pertinence des modèles physiques, la convivialité pour l'utilisateur, le caractère adapté des bases de données et du manuel opérateur.

The automotive industry is moving toward intelligent systems. The aim for more safety, comfort, or even full self-driving systems requires the vehicles to take actions instead of the driver. It may use light signals, brake, accelerate, turn, and shift gears. Performing safely such actions requires a decision-making process that anticipates the resulting situation. This is broken down into three "p" steps: perception, prediction, and planning. The perception system recognizes the current surrounding road-scene situation. The prediction system forecasts the future of the road-scene including the other road users. The planning system produces a driving intention.If the future was perfectly known, planning would be straight forward. However, the perception system makes partial and noisy observations. The future cannot be perfectly predicted because of the uncertainties in the observation and because the human driver's decisions are modeled imperfectly. Therefore, improving the motion forecasting model that can work with a noisy observation system in complex situations is a critical point for safety, comfort, and future applications toward autonomous vehicles.Motion forecasting can be modeled from various perspectives. The three main ones are kinematics and heuristics, statistics, and decision process. The kinematics and heuristics are the historical approaches that offer efficiency and robustness. Most vehicles using short-term forecasting systems on the road nowadays rely on such forecasting models. However, it leads to an overly conservative behavior when used in complex situations. The approach using decision processes shows good performance in complex scenarios. It is able to perform well in simulations and controlled environments. It combines forecasting and planning into a single task and may account for the reactions of the other drivers in the decisions it plans to take. However, in a noisy and wider, uncontrolled environment, statistical approaches still produce the best performances.In this work, we use neural networks to learn the statistics of the vehicle trajectories. We progressively build a motion forecasting model from a constant velocity baseline to a complex interaction-aware neural network model. The evaluation criteria that we establish are used to judge the quality of the forecast and to compare the models. The likelihood of future observation for the forecasted distribution is the main criterion that is commonly used in the applications. However, there is no universal forecasting quality criterion and it remains an open problem.We begin our tests with vanilla neural networks for maximum likelihood motion forecasting. These models are then modified to also learn to fit the expected forecasting error. They optimize the NLL. It is a likelihood criterion for a given dataset of trajectories. This does not lead to much improvement over the constant velocity model. We go on to add interaction awareness to the model using multi-head attention. This brings much improvement to the forecasts but it is still insufficient. We improve the model further by considering different future possibilities. Finally, the multi-head attention model is extended to also attend to the surrounding lane shapes. The resulting neural network counts several blocks that account for different aspects of the task. Experiments show that each part of the model is useful. We show that the trained model has learned specialized attention patterns and is able to make multi-modal forecasts. Our results were the winning entry at the two first Argoverse forecasting competition.

A research program has been carried out at INERIS aiming to quantify rockburst potential from mining-induced fault-slip. As a part of the research, numerical modeling of fractured rock mass has been undertaken, using the three-dimensional distinct element code 3DEC. Results presented in this paper demonstrate a very good agreement between calculated deformations of modeled faults and the experienced rockburst sequence of the Estaque-sud district of the colliery

Permanent Magnet Assisted Synchronous Reluctance Motor is one of the new motors introduced in transportation industry, which have been introduced as a possible tractions motors in hybrid electric vehicle applications. Achieve maximum torque per ampere (MTPA), knowledge of the motor parameters is necessary. Due to the high ambient temperature inside the engine cavity and also saturation effect, variation of the motor parameters such as inductances and permanent magnets flux density is not avoidable. In this paper, motor equations in biaxial system are described, then a method is presented for vector control considering maximum torque per Ampere. Then, this method is implemented on a Reluctance Synchronous Motor Reinforced with Magnet using Simulink. Simulation results show well performance of the designed control system in a wide range of speed.

Background: In developing countries, malnutrition is a contributing factor in over 50% of child deaths. Mortality rates are higher in underweight children, and HIV-infection is known to increase underweight. Our goals were to evaluate the prevalence of HIV among children hospitalised for severe malnutrition (SM) at the Niamey national hospital (Niger), and to compare renutrition and mortality by HIV-status. Methods: Retrospective study based on all children

This paper presents an approach to estimate link travel time in urban areas. This approach consists of a data fusion from underground loop detectors and probe vehicles equipped with global positioning system (GPS). This method is expected to be more accurate, reliable and robust than using either of these data sources alone. In this approach, an algorithm is developed. This algorithm is based on the unscented Kalman filter using vehicle counts and flows from loop detectors located at the end of every link, and travel time from probe vehicles. From these counts the average travel time is calculated using the “cumulative plot” method. Furthermore, in order to incorporate the GPS data, a map-matching method is used to associate a travel time to the appropriate link.

Cette étude du cadre juridique des investissements étrangers au Brésil a pour objet, d’une part, de présenter et d’analyser les dispositions de droit interne et de droit international qui régissent la réalisation d’un investissement étranger au Brésil, et, d’autre part, de démontrer, au travers de cette analyse, l’étroite corrélation qui existe entre les objectifs économiques d’un pays et sa politique économique en matière d’investissement. Un bref rappel de l’évolution du régime juridique de l’investissement étranger au Brésil depuis l’accession de ce pays à l’indépendance en 1822 jusqu’à son entrée sur la scène internationale au cours du XIXe siècle s’avèrera nécessaire non seulement pour démontrer le rôle essentiel et continu des investissements étrangers dans le développement économique du Brésil mais aussi pour souligner les changements opérés à cause des capitaux étrangers sur le soft power du Brésil à l’échelle régionale et mondiale dès cette époque jusqu’aujourd’hui. L’analyse de la spécificité de l’actuel régime juridique des investissements étrangers au Brésil s’effectuera donc en deux temps. Dans une première partie, intitulée « L’absence d’un régime juridique classique des investissements internationaux », sera présentée l’évolution de ce régime né de la nécessité d’attrait des investisseurs étrangers par et pour l’économie de l’Etat, et le postérieur recours à l’internationalisation de l’économie nationale afin de créer un climat favorable aux investissements. Dans une deuxième partie, intitulée « La spécificité du régime de protection juridictionnelle des investissements internationaux au Brésil », seront analysés plus en détail l’originalité de ce régime sui generis né de la nécessité de sécuriser les investissements internationaux ainsi que le recours à l’arbitrage dans les conflits entre l’Etat et les investisseurs étrangers dans le but de conformer cette protection juridictionnelle aux exigences du règlement international des investissements (conventions bilatérales pour la promotion et la protection mutuelles des investissements et accords multilatéraux relatifs aux investissements étrangers).