Corps du génie de l'armée des États-Unis

Le Corps du génie de l’armée de terre des États-Unis (United States Army Corps of Engineers ou USACE) est une institution de génie civil et de logistique militaire qui emploie environ et (hommes et femmes) dépendant du département de la Défense et rattaché à l'armée de terre des États-Unis. Sa devise est , en français dans le texte. Sa mission, comparable à celle des ponts et chaussées en France, est de fournir des services tels que la construction de barrages ou d'autres projets d'aménagement. L'histoire du corps commence en 1775 lorsque le congrès continental autorise le premier chef du génie (chief engineer) en à bâtir des fortifications près de Boston à Bunker Hill. Le corps était alors composé de Français embauchés par le général George Washington. En 1802, le corps se fixa à West Point et devint la première académie militaire des États-Unis. Histoire L'histoire du United States Army Corps of Engineers remonte à l'ère révolutionnaire. Le , le Congrès continental or

Teaching Transversal Skills in the Engineering Curriculum: the Need to Raise the Temperature

Lucille Delisle, Helena Kovacs, Mirjam Mekhaiel, Roland John Tormey, Pascal Vuilliomenet

Engineers and architects today are dealing with great social, technical and environmental complexities, and the demand for having broadly educated holistic engineers will only continue to grow in the future. Being able to manage and lead diverse teams, understand complex, interdisciplinary systems and solve open-ended problems across and beyond different subjects is expected from the next generation of graduates. With the aim to understand how the future graduates are educated to cope with such complexities, we developed a tool to map out the course curricula and examined the extent to which transversal skills are taught at a leading technical university in Europe. Using MATLAB, we have conducted an exploratory analysis, and this concept paper offers the outcomes of analysing course descriptions of bachelor and master programmes throughout the academic year 2018-2019. By presenting the results in a visual form of a heatmap, we have examined at which moment throughout the curriculum and how frequently are transversal skills included in the teaching objectives. The results indicate an overall gap between teaching transversal skills at both BA and MA level, but also a difference in teaching transversal skill in mandatory and optional courses. Furthermore, throughout the curriculum we observed a significant lack of some critical skills, such as those connected to ethical reasoning. This project opened valuable avenue to deepen the discussion regarding teaching and learning of transversal skills, as well as the structural changes that need to be considered in the education of the engineers and architects in future.

University of Twente2020

Escapement-Based Movements as Positioning Mechanisms: Design and Modelling

Romain David Besuchet

This work has been triggered by an industrial project targeting the design of a mechatronic injector for the medical field. Injections are usually performed using a syringe, a quite clumsy tool that transforms the injection task in a positioning one. The quality of injections can be enhanced by using devices that help control the injected dose, or the injection rate, but usually at the cost of a slower operation, a reduced manoeuvrability, or a short battery life for electrically-powered devices. The idea was therefore to provide a cordless miniaturised injector capable of managing the dosage as well as injection rate according to the user's desires, with the constraint that it should have a long battery life. This is why escapementbased movements are investigated in this work. Such stepper movements, where a regulator controls the speed at which a stock of mechanical energy is emptied, have been used for centuries in clockwork. Purely mechanical devices, the regulators are designed to work at a given frequency, with the stability of said frequency as the main objective. For the discussed application, the use of an electronic regulator permits variable injection rates and simplifies dosage control. Beingmostly used in clockwork, escapement-based movements are hardly mentioned, let alone studied, outside this field in the literature. This research is aimed at filling this void to provide engineers with the basics for the design of escapement-based movements, using Pahl & Beitz's design methodology. First of all, a general structure of suchmovements is proposed. Using functional analysis, a canvas for the requirements specification of a movement is given. To ensure an efficient and fast evaluation of the quality of a solution at any stage of the development, modelling and design tools are suggested. The industrial project is then used as a case study that exemplifies the concepts introduced. The requirements, a selected functioning principle, and the main technical solutions are described. The application of the modelling tools is done in two parts, representing two subsystems designed concurrently but separately: the purely mechanical part of the movement that includes the escapement, and the mechatronic regulator. The dynamic and energetic performances of both subsystems are modelled, using relevant techniques. Analytical models characterise the mechanical part of the system, using advantageously the stepper nature of the system. Because they are analytical, the models require very limited computational resources and are thus extremely convenient design tools. They also permit a stochastic study of the influence of manufacturing tolerances on said performance. Regulators, in particular electronically-controlled ones, are then discussed. An optimisation strategy for highly constrained problems is proposed. It consists in first optimising a set of input parameters towards acceptable values for the constraints. Once one or more sets of parameters respecting the constraints are found, these sets are used as initial points for the actual optimisation of the objectives. The efficacy of this strategy is demonstrated by an example. Finally, a prototype of the devised escapement-based movement is presented. It is used to establish the validity of the developedmodels, but also demonstrate the capabilities of the retained functioning principle.

EPFL2016

Influencing river morphodynamics by means of a bubble screen - application to open-channel bends

Violaine Dugué

Curved reaches and bends are a characteristic feature of rivers and channels. Their morphology is heterogeneous and typically includes a point bar at the inner side of bends, and bend scour at the outer side. Curvature-induced secondary flow, also called spiral flow or helical flow, is known to play an important role in the generation of this morphological heterogeneity. This secondary flow is outward directed in the upper part of the water column, and causes an increase of velocities and erosive capacity at the outer side of the channel. Near the outer bank, the secondary flow has an important vertical component that impinges on the channel bed and enhances bend scour. The eroded sediment is then transported in inward direction by the near-bed component of the secondary flow, and contributes to the development of the point bar at the inner side of the channel. The morphological heterogeneity has adverse effects: scour at the outer side of the bend threatens the stability of the bank and structures like bridge abutments or piers, and deposition of sediment at the inner side of the bend reduces the navigable width. Therefore, river engineers have always tried to attenuate this morphological heterogeneity, for example by artificially roughening the outer bank in order to reduce near-bank velocities, or deflecting the flow away from the outer bank by means of groynes or bottom vanes. All these techniques involved permanent fixed structures. Dr. Violaine Dugué has investigated an innovative technique that is reversible and does not involve fixed structures. It consists in generating an air-bubble screen with a porous tube that is positioned parallel to the outer bank. The rising air-bubbles generate a secondary flow that is opposed to the curvature-induced secondary flow, and thereby reduces the morphological heterogeneity. Dr. Violaine Dugué has performed a series of laboratory experiments with increasing degree of complexity, including straight and curved flows under various conditions of sediment transport. These experiments provided insight in the mutual interactions between the main flow, the curvature-induced flow components, the bubble-screen induced flow components, the sediment transport and the morphology. Based on this novel insight, Dr. Violaine Dugué has developed a methodology that allows quantifying the application range of the bubble-screen technique. It relates the required air discharge of the bubble screen to the geometric and hydraulic characteristics of the open-channel bend. The methodology is illustrated by means of two case studies.

EPFL - LCH2013