États-Unis | EPFL Graph Search

Les États-Unis (prononcé : ), en forme longue les États-Unis d'Amérique, également appelés informellement les USA ou moins exactement lAmérique ou encore les States (en anglais : United States, United States of America, US, USA, America), sont un État transcontinental dont la majorité du territoire se situe en Amérique du Nord. Les États-Unis ont la structure politique d'une république et d'un État fédéral à régime présidentiel, composé de cinquante États. La capitale fédérale, Washington, est située dans le district de Columbia, une zone enclavée dans l'Union, mais hors des cinquante États. La monnaie est le dollar américain. Il n'y a pas de langue officielle aux États-Unis, bien que la langue nationale soit de facto l'anglais américain. 48 des sont adjacents et forment le Mainland. Celui-ci est encadré par l'océan Atlantique à l'est, le golfe du Mexique au sud-est et l'océan Pacifique à l'ouest, et se trouve bordé au nord par le Canada et au sud-ouest par le Mexique. Les deux Éta

Development of a musculoskeletal model of the knee joint to predict articular contact patterns during a loaded squat movement

Alexandra Stephanie Krause

Computational models are a current way to study specific behavior of healthy or pathological tissue or the mechanics of joints. Simulating the native anatomical structures and kinematics are two of the most important tasks to achieve reliable results. It is especially challenging for the knee as it is one of the most complex joint in the human body. It consists of two articulations, one between femur and tibia and one between femur and patella. This thesis estimates the patellofemoral and tibiafemoral contact pattern during a simulated squat movement. This is achieved by using a musculoskeletal, loaded knee model controlled by muscle activation. The flexion is performed by the elongation of the rectus femoris muscle. The knee model consists of femural, patellar and tibial articular cartilage, the menisci, anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments. Contours of all soft tissues were segmented on the magnetic resonance imaging slides and imported into Solidworks (SolidWorks Corp., Concord, MA, United States) to build up the 3D geometry. A previous thesis already reconstructed the tibia, femur, fibula and patella bone geometry from Computed tomography images, so cartilage and menisci were done during this study. Abaqus (Dassault Systèmes Simulia Corp., Rhode Island, USA) was used for finite element modeling. The cartilage and menisci were meshed with hexahedral elements and bones were modeled as rigid bodies. An explicit solver was chosen for the numerical simulation and the squat movement should be performed quasi static. Mass scaling was required to reduce computational time and a global damping was used to minimize the oscillations. But sill, the squat movement could not be performed.

2010

L'oeuvre de Leandro V. Locsin (1928-1994), architecte à la recherche de l'identité élusive de l'architecture philippine du second après-guerre

Jean-Claude Girard

Filipino architect Leandro Valencia Locsin (Silay1928 - Makati 1994) produced an architectural work that involved 250 projects, of which at least more than half were completed and mostly in his country of origin. A graduate in architecture of San Tomas de Manila University in 1953, his career began after the Second World War, which left the capital city all but destroyed following airstrikes by the allies that served to liberate the Philippines from the Japanese occupying forces. Following his studies, Locsin is immediately solicited with requests which leads him to open his office and give up the idea of completing his graduate studies in one of the prestigious American universities, which at the time had welcomed great masters who had sought exile from Europe to the United States in the 1930s. For a member of a privileged social class, this atypical career path makes Locsin a singular figure in the architectural landscape as he will immediately focus his interest on questioning the specificity of Filipino architecture. In a 1989 interview, Locsin confirms his career-long interest in researching the boundaries between local culture and international influences. The study of the vernacular tradition in his country will orient his work towards defining certain architectural principles to allow for the emergence of a new contemporary Filipino architecture. The post-war period, involving innovations in technical resources and favorable political and economic conditions for urban development, will serve to render all the more complex a body of work that is difficult to apprehend and qualify. In a 1964 text, Locsin refers to the elusive identity of the Filipino architectural spirit which, according to him, is the result of an assimilation of various external influences, given the geographic positioning of the Philippines and its colonial past. His work never ceased to reflect this quest for identity in built representations. While Leandro V. Locsin has been called "the poet of space" for the quality of his projects characterized by a great attention given to the sense of space, abstraction, symmetry, proportion, and materiality linked to the use of concrete and traditional materials his work has never been the subject of a complete study. Few scientific contributions exist and remain partial, in that they focus on certain specificities of his production. Further, there are no studies that offer a complete review of his office archives, a necessary step towards uncovering and highlighting the unique characteristics of a multiform production. The objective of this dissertation is to provide a complete overview of the work of Leandro V. Locsin, notably through a survey of his projects, and an analysis of the condition of their production in a local and international context, in order to render explicit the specific qualities that make this work a unique example of architecture of the period and from the Philippines.

EPFL2018

District scale influence of waste heat on the subsurface conditions: a numerical investigation for Chicago

Stéphane Hartmann

Since the 20th century, the rate of urbanization in the world has been increasing exponentially and will reach 68% in 2050. In parallel with this expansion, the size and activities of cities are also greatly growing. As a result, cities are depleting available space and energy resources at an alarming rate. In order to be able to respond to these demands, the solution of building more underground structures is being put in place and is already being implemented in some megacities. These infrastructures have demonstrated that human activity is the factor that generates the main heat flow in the underground and that it has a significant impact on the temperature of urban aquifers. Through the use of geothermal energy, the increase in temperature of the subsoil can be ecologically and economically beneficial. However, for the evaluation of the geothermal potential, many factors have to be taken into consideration (geology, human activities, urban planning, etc), making its execution complex. As a result, most of the research already undertaken on this subject proves to be sketchy and incomplete. This work thus proposes a complete study of the influence of the different heat sources on the subsoil. For this purpose, a unique FE THM (Thermo-hydro-mechanical) model simulating the heat losses from underground structures into the ground over a 50-year period has been developed for the Loop District in Chicago (USA). It can also be adapted to any other region for which geological and underground structural data are available. The case study is challenging due to its relevance and location. Indeed, the Loop remains the second largest commercial district in the United States after Midtown Manhattan and statistics show that it consumes one third of Chicago’s annual energy. By this means, the importance and necessity of addressing this topical issue is shown. This study analyses the impact of heat sources on the thermal, mechanical and hydraulic properties of the subsurface while demonstrating a latency time observed between thermal and mechanical effects. The hydraulic investigations carried out have demonstrated the constancy as well as the very low impact of the groundwater flow over the time in Chicago. A detailed study on the interaction of the different heat sources showed that the combined effect of the different heat sources present (basement, subway and ambient air) is the sum of the effects of each of them separately. Finally, it demonstrated that the contribution of the heat sources to the thermal and mechanical variations always undergoes the same process over time and the same final distribution: 70% for the basements, 30% for the underground subway lines and >1% for the ambient air.

2020