Development of charts for determining shear, moment and normal stresses in circular, rectangular and elliptical rings, such as are used in transverse frames of fuselages

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Aeronautical Engineering, 1941.MIT Institute Archives copy bound with: Hudson, Walter Davidson. Structural design of a plastic airplane (1941).Includes bibliographical references (leaf [12]).by Fernand Lecavalier.B.S

New Interfaces in the Automated Landscapes of Logistics

Metaphors of flows are often used to describe aspects of logistics, thereby suggesting smooth and inevitable operations while also obscuring the frictions and contingencies that characterize the industry. This article explores the consequences and possibilities of these modes by first elaborating some aspects of logistical operations in order to connect them to the contemporary built environment. It looks at the architectural components of the company Walmart in order to present hypothetical scenarios related to the future of the logistical landscape. By connecting these visual experiments to questions of representation, automation, and systems thinking, the article explores the ways we might challenge and extend the possibilities of logistics

Développement d'une unité de valves motorisées et algorithme de transition pour actionnement hydrostatique bimodal d'une jambe robotique

Les robots mobiles, tels que les exosquelettes et les robots marcheurs, utilisent des actionneurs qui doivent satisfaire à une large plage de requis de force et de vitesse. Par exemple, pour le cycle de marche d’une jambe robotique, la phase d’appui nécessite une force élevée tandis que la phase de balancement requiert une grande vitesse. Pour satisfaire ces requis opposés, le dimensionnement d’un système d’actionnement traditionnel à rapport de réduction unique conduit généralement à un moteur électrique lourd, surdimensionné et à une faible efficacité énergétique. Ainsi, l’alternative explorée est une architecture hydrostatique à deux vitesses où des valves motorisées sont utilisées pour reconfigurer dynamiquement le système entre deux modes de fonctionnement : fort ou rapide. La complexité réside dans le choix d’une technologie de valve légère ainsi que dans le développement d’un algorithme de contrôle permettant de réaliser les transitions de manière rapide et fluide. Un prototype d’une unité de valves motorisées est conçu et intégré dans l’architecture hydrostatique complète de l’actionneur et un banc d’essai d’une jambe robotique est fabriqué. Trois stratégies de contrôle des moteurs sont comparées lors du changement de mode : une vitesse constante, une diminution de vitesse et une réduction du courant. La méthode choisie, le contrôle en courant, est ensuite utilisée pour la démonstration des phases d’appui et de balancement de la jambe robotique. Par cette méthode, il est possible d’effectuer des transitions rapides, de maintenir une force suffisante et de minimiser les oscillations qui surviennent lors du contact avec le sol. Ces travaux offrent donc un premier point de comparaison au niveau du choix de valves, de la masse, de la vitesse d’actionnement et de la stratégie de contrôle

Analyse de l’intelligibilité de textes prescriptifs

L’intelligibilité des textes, telle que nous la définissons, tient compte de l’ensemble des composantes qui en assure la compréhension complète. Nous ne nous limitons pas à considérer les aspects microstructurels (nombre de mots, de phrases, etc.) comme le font les mesures de lisibilité traditionnelles; nous tenons également compte des aspects macrostructurels, ceux qui marquent la progression du texte. Nous présentons ici un instrument qui permet de mesurer cette intelligibilité. Nous l’avons appliqué à des textes prescriptifs (un document bancaire et un document administratif) qui causaient des difficultés de compréhension.Far beyond the traditional definition of readibility that takes into account essentially microstructures variables such as word frequency, sentence-length, etc., the definition of readibility that governed this research also includes macrostructure variables, mainly those variables structuring the progression of text. "Comprehensibility" would be the closest english term to define our readibility concept. This article describes how one can measure the comprehensibility of a text in terms of identifying its progression. Our measure was applied to two prescriptive texts: one bank document and one administrative document. Both documents had been judged as presenting comprehension difficulties

The environment and emancipation in critical security studies: the case of the Canadian Arctic

The traditionally dominant discourse of The Great White North views Canada as a land of vast wilderness and abundant resources. However, this discourse excludes growing environmental risk and prevalent insecurity felt by vulnerable populations in Canadian society, namely indigenous groups whose livelihoods are deeply dependent upon their relationship with their environments. The effect of the relationship between the physical environment and conceptions of security can contribute to a deeper understanding of traditional and critical accounts of security. This article investigates traditional Canadian environmental security discourses and alternative environmental security discourses promoted by Arctic Inuit groups. It examines how these discourses impact the analytic and normative goals of critical security studies and interprets the way in which they affect the concept of emancipation. It argues that Canadian security is co-constituted with its understanding of the environment, and that the Canadian case compels an expansion of the notion of the referent object of security to include the environment – a change which throws it into contrast with other schools of critical security, whose visions of emancipation might not, as currently theorized, be equipped to overcome these phenomena

Entangling carbon lock-in: India’s coal constituency

This article investigates how energy security in the Anthropocene is entangled in diffuse ways with materiality. In particular we examine the social-material entanglement of humans and coal in India and how coal manifests itself differently across social life in the country. Focusing on a single material allows us to study how the Anthropocene creates, and is created by, particular appropriations of the material world. It offers a corrective to some Anthropocene literature that avoids discussing the complex, “everyday,” social impacts that fossil fuels have, particularly in the developing world. These intertwined impacts add to the complexity and difficulty in the process of decarbonizing societies, or in transitioning to a sustainable energy future

Aide stratégique en lecture et écriture

2e éd.Également disponible en version papierTitre de l'écran-titre (visionné le 13 janv. 2010)Vol.1 Guide d'intégration. -- v.2 Cahier d'écriture. -- v.3 Cahier de tutora

Glacial Isostatic Adjustment (GIA) in Greenland: A Review

Using the most recently published regional and global deglaciation histories we provide updated estimates of the Glacial Isostatic Adjustment (GIA) component of present day uplift at a suite of GPS sites in Greenland. The GIA of the solid Earth beneath Greenland contributes -6 to +10 Gt/yr to the present day mass trends observed by the Gravity Recovery and Climate Experiment (GRACE), representing <5% contribution to the observed mass trends over the last decade. Although the contribution of GIA to GRACE estimates of mass imbalance is insignificant for Greenland as a whole, differences between deglacial models reviewed here and their assumed viscoelastic Earth structures result in significantly different estimates of regional patterns and magnitudes of GIA. This means that for some areas of Greenland (e.g. the north-west, south- and north-east) the use of GNSS to estimate elastic uplift patterns is more affected by the choice of GIA correction applied