Center of pressure (fluid mechanics)In fluid mechanics, the center of pressure is the point where the total sum of a pressure field acts on a body, causing a force to act through that point. The total force vector acting at the center of pressure is the surface integral of the pressure vector field across the surface of the body. The resultant force and center of pressure location produce an equivalent force and moment on the body as the original pressure field. Pressure fields occur in both static and dynamic fluid mechanics.
Elasticity (physics)In physics and materials science, elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to plasticity, in which the object fails to do so and instead remains in its deformed state. The physical reasons for elastic behavior can be quite different for different materials.
Clavicle fractureA clavicle fracture, also known as a broken collarbone, is a bone fracture of the clavicle. Symptoms typically include pain at the site of the break and a decreased ability to move the affected arm. Complications can include a collection of air in the pleural space surrounding the lung (pneumothorax), injury to the nerves or blood vessels in the area, and an unpleasant appearance. It is often caused by a fall onto a shoulder, outstretched arm, or direct trauma. The fracture can also occur in a baby during childbirth.
Segond fractureThe Segond fracture is a type of avulsion fracture (soft tissue structures pulling off fragments of their bony attachment) from the lateral tibial plateau of the knee, immediately below the articular surface of the tibia (see photo). Because of the high rate of associated ligamentous and meniscal injury, the presence of a Segond or reverse Segond fracture requires that these other pathologies must be specifically ruled out. Or more pragmatically, the orthopaedic team assume that the presence of Segond fracture equals ACL rupture, as the correlation is close to 100%.
TriboluminescenceTriboluminescence is a phenomenon in which light is generated when a material is mechanically pulled apart, ripped, scratched, crushed, or rubbed (see tribology). The phenomenon is not fully understood, but appears to be caused by the separation and reunification of static electrical charges. The term comes from the Greek τρίβειν ("to rub"; see tribology) and the Latin lumen (light). Triboluminescence can be observed when breaking sugar crystals and peeling adhesive tapes.
PermeationIn physics and engineering, permeation (also called imbuing) is the penetration of a permeate (a fluid such as a liquid, gas, or vapor) through a solid. It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. Permeation is modeled by equations such as Fick's laws of diffusion, and can be measured using tools such as a minipermeameter. The process of permeation involves the diffusion of molecules, called the permeant, through a membrane or interface.
Broken fingerA broken finger or finger fracture is a common type of bone fracture, affecting a finger. Symptoms may include pain, swelling, tenderness, bruising, deformity and reduced ability to move the finger. Although most finger fractures are easy to treat, failing to deal with a fracture appropriately may result in long-term pain and disability. The cause is usually traumatic injury. These are most commonly falls, crushing injuries, and sports injuries. Pathological fractures, from an infection or a tumour, are rarer.
