Acyanotic heart defectAn acyanotic heart defect, is a class of congenital heart defects. In these, blood is shunted (flows) from the left side of the heart to the right side of the heart, most often due to a structural defect (hole) in the interventricular septum. People often retain normal levels of oxyhemoglobin saturation in systemic circulation. This term is outdated, because a person with an acyanotic heart defect may show cyanosis (turn blue due to insufficient oxygen in the blood).
Atrioventricular septal defectAtrioventricular septal defect (AVSD) or atrioventricular canal defect (AVCD), also known as "common atrioventricular canal" or "endocardial cushion defect" (ECD), is characterized by a deficiency of the atrioventricular septum of the heart that creates connections between all four of its chambers. It is a very specific combination of 3 defects: 1) Atrial Septal Defect (ASD), a hole in the wall between the right and left atria; 2) Ventricular Septal Defect (VSD), a hole in the wall between the right and left ventricles; and 3) Abnormalities of the mitral and/or tricuspid valves.
Atrial septal defectAtrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA). After PFO closure the atria normally are separated by a dividing wall, the interatrial septum.
General officerA general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel. The term general is used in two ways: as the generic title for all grades of general officer and as a specific rank. It originates in the 16th century, as a shortening of captain general, which rank was taken from Middle French capitaine général.
CementA cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
Portland cementPortland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available.
Deformation (engineering)In engineering, deformation refers to the change in size or shape of an object. Displacements are the absolute change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the relative internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve.
FractureFracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially, it is called a shear crack, slip band or dislocation. Brittle fractures occur without any apparent deformation before fracture.
Brigadier generalBrigadier general or Brigade general is a military rank used in many countries. The rank is usually above a colonel, and below a major general or divisional general. When appointed to a field command, a brigadier general is typically in command of a brigade consisting of around 4,000 troops (four battalions). Brigadier general (Brig. Gen.) is a military rank used in many countries. It is the lowest ranking general officer in some countries, usually sitting between the ranks of colonel and major general.
Colonel generalColonel general is a three- or four-star military rank used in some armies. It is particularly associated with Germany, where historically general officer ranks were one grade lower than in the Commonwealth and the United States, and Generaloberst was a rank above full General, but below Generalfeldmarschall. The rank of colonel general also exists in the armed forces organized along the lines of the Soviet model, where it is comparable to that of a lieutenant general in many NATO armed forces (rank code OF-8).
Fracture mechanicsFracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture. Theoretically, the stress ahead of a sharp crack tip becomes infinite and cannot be used to describe the state around a crack. Fracture mechanics is used to characterise the loads on a crack, typically using a single parameter to describe the complete loading state at the crack tip.
Scattering parametersScattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behavior of linear electrical networks when undergoing various steady state stimuli by electrical signals. The parameters are useful for several branches of electrical engineering, including electronics, communication systems design, and especially for microwave engineering. The S-parameters are members of a family of similar parameters, other examples being: Y-parameters, Z-parameters, H-parameters, T-parameters or ABCD-parameters.
