Built environmentThe term built environment refers to human-made conditions and is often used in architecture, landscape architecture, urban planning, public health, sociology, and anthropology, among others. These curated spaces provide the setting for human activity and were created to fulfill human desires and needs. The term can refer to a plethora of components including the traditionally associated buildings, cities, public infrastructure, transportation, open space, as well as more conceptual components like farmlands, dammed rivers, wildlife management, and even domesticated animals.
Environmental impact of concreteThe environmental impact of concrete, its manufacture, and its applications, are complex, driven in part by direct impacts of construction and infrastructure, as well as by CO2 emissions; between 4-8% of total global CO2 emissions come from concrete. Many depend on circumstances. A major component is cement, which has its own environmental and social impacts and contributes largely to those of concrete. The cement industry is one of the main producers of carbon dioxide, a potent greenhouse gas.
Sustainable livingSustainable living describes a lifestyle that attempts to reduce the use of Earth's natural resources by an individual or society. Its practitioners often attempt to reduce their ecological footprint (including their carbon footprint) by altering their home designs and methods of transportation, energy consumption and diet. Its proponents aim to conduct their lives in ways that are consistent with sustainability, naturally balanced, and respectful of humanity's symbiotic relationship with the Earth's natural ecology.
Special operationsSpecial operations or spec ops are military activities conducted, according to NATO, by "specially designated, organized, selected, trained, and equipped forces using unconventional techniques and modes of employment." Special operations may include reconnaissance, unconventional warfare, and counterterrorism, and are typically conducted by small groups of highly trained personnel, emphasizing sufficiency, stealth, speed, and tactical coordination, commonly known as special forces.
Structural steelStructural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a of a specific cross section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries. Most structural steel shapes, such as -beams, have high second moments of area, which means they are very stiff in respect to their cross-sectional area and thus can support a high load without excessive sagging.
Composite à matrice céramiquethumb|260px|Surface de cassure d'un composite constitué de fibres de SiC et d'une matrice de SiC.thumb|260px|Coussinets céramiques de paliers de diamètres de en CMC pour de grandes pompes. Les composites à matrice céramique ou CMC sont des matériaux composites faisant partie des céramiques techniques. Ils sont caractérisés par un ensemble de fibres céramiques incorporées dans une matrice également céramique. Fibres et matrice peuvent en principe être constituées de toutes les céramiques connues, en y incluant même le carbone.
Raideur (mécanique)vignette|Rigidité d'un ressort hélicoïdal La raideur est la caractéristique qui indique la résistance à la déformation élastique d'un corps (par exemple un ressort). Plus une pièce est raide, plus il faut lui appliquer un effort important pour obtenir une déflexion donnée. Dans certains secteurs, son inverse est appelé souplesse ou flexibilité. Pour d'autres, la souplesse est définie par au moins deux données, et . De ce fait, la souplesse ne peut rigoureusement pas être l'inverse de la raideur.
