Rolling-element bearingIn mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two concentric, grooved rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding. One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top.
Russian RevolutionThe Russian Revolution was a period of political and social change in the Russian Empire, starting in 1917. This period saw Russia abolish its monarchy and adopt a socialist form of government following two successive revolutions and a bloody civil war. The Russian Revolution can also be seen as the precursor for the other European revolutions that occurred during or in the aftermath of World War I, such as the German Revolution of 1918–1919. The Russian Revolution was inaugurated with the February Revolution in early 1917.
Iranian RevolutionThe Iranian Revolution (انقلاب ایران, Enqelâb-e Irân ʔeɴɢeˌlɒːbe ʔiːɾɒːn), or the Islamic Revolution (انقلاب اسلامی, Enqelâb-e Eslâmī), was a series of events that culminated in the overthrow of the Pahlavi dynasty in 1979. The revolution also led to the replacement of the Imperial State of Iran by the present-day Islamic Republic of Iran, as the monarchical government of Mohammed Reza Pahlavi was superseded by the theocratic government of Ruhollah Khomeini, a religious cleric who had headed one of the rebel factions.
Bearing (mechanical)A bearing is a machine element that constrains relative motion to only the desired motion and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction.
Thrust bearingA thrust bearing is a particular type of rotary bearing. Like other bearings they permanently rotate between parts, but they are designed to support a predominantly axial load. Thrust bearings come in several varieties. Thrust ball bearings, composed of bearing balls supported in a ring, can be used in low thrust applications where there is little axial load. Cylindrical thrust roller bearings consist of small cylindrical rollers arranged flat with their axes pointing to the axis of the bearing.
StoveA stove or range is a device that burns fuel or uses electricity to generate heat inside or on top of the apparatus, to be used for general warming or cooking. It has evolved highly over time, with cast-iron and induction versions being developed. Stoves can be powered with many fuels, such as electricity, gasoline, wood, and coal. Due to concerns about air pollution, efforts have been made to improve stove design. Pellet stoves are a type of clean-burning stove.
Deep foundationA deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. There are many reasons that a geotechnical engineer would recommend a deep foundation over a shallow foundation, such as for a skyscraper.
MaterialMaterial is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials, their properties and their applications. Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials.
Wood-burning stoveA wood-burning stove (or wood burner or log burner in the UK) is a heating or cooking appliance capable of burning wood fuel, often called solid fuel, and wood-derived biomass fuel, such as sawdust bricks. Generally the appliance consists of a solid metal (usually cast iron or steel) closed firebox, often lined by fire brick, and one or more air controls (which can be manually or automatically operated depending upon the stove). The first wood-burning stove was patented in Strasbourg in 1557.
Franklin stoveThe Franklin stove is a metal-lined fireplace named after Benjamin Franklin, who invented it in 1742. It had a hollow baffle near the rear (to transfer more heat from the fire to a room's air) and relied on an "inverted siphon" to draw the fire's hot fumes around the baffle. It was intended to produce more heat and less smoke than an ordinary open fireplace, but it achieved few sales until it was improved by David Rittenhouse. It is also known as a "circulating stove" or the "Pennsylvania fireplace".
Gas stoveA gas stove is a stove that is fuelled by combustible gas such as syngas, natural gas, propane, butane, liquefied petroleum gas or other flammable gas. Before the advent of gas, cooking stoves relied on solid fuels such as coal or wood. The first gas stoves were developed in the 1820s and a gas stove factory was established in England in 1836. This new cooking technology had the advantage of being easily adjustable and could be turned off when not in use.
Constraint programmingConstraint programming (CP) is a paradigm for solving combinatorial problems that draws on a wide range of techniques from artificial intelligence, computer science, and operations research. In constraint programming, users declaratively state the constraints on the feasible solutions for a set of decision variables. Constraints differ from the common primitives of imperative programming languages in that they do not specify a step or sequence of steps to execute, but rather the properties of a solution to be found.
