Efficient energy useEfficient energy use, sometimes simply called energy efficiency, is the process of reducing the amount of energy required to provide products and services. For example, insulating a building allows it to use less heating and cooling energy to achieve and maintain a thermal comfort. Installing light-emitting diode bulbs, fluorescent lighting, or natural skylight windows reduces the amount of energy required to attain the same level of illumination compared to using traditional incandescent light bulbs.
Linear programming relaxationIn mathematics, the relaxation of a (mixed) integer linear program is the problem that arises by removing the integrality constraint of each variable. For example, in a 0–1 integer program, all constraints are of the form The relaxation of the original integer program instead uses a collection of linear constraints The resulting relaxation is a linear program, hence the name.
2007–2008 world food price crisisThe world food price crisis refers to a period of time when the cost of food increased significantly and had a profound impact on the availability and affordability of food for people around the world. This crisis is often characterized by sharp spikes in the prices of key staple foods such as wheat, rice, and corn, as well as other agricultural commodities such as sugar and oil. The causes of the world food price crisis are complex and multifaceted, but they generally involve a combination of factors including droughts and other weather-related events, increased demand for biofuels, trade policies, and financial speculation.
History of steam road vehiclesThe history of steam road vehicles comprises the development of vehicles powered by a steam engine for use on land and independent of rails, whether for conventional road use, such as the steam car and steam waggon, or for agricultural or heavy haulage work, such as the traction engine. The first experimental vehicles were built in the 18th and 19th century, but it was not until after Richard Trevithick had developed the use of high-pressure steam, around 1800, that mobile steam engines became a practical proposition.
Indicator diagramAn indicator diagram is a chart used to measure the thermal, or cylinder, performance of reciprocating steam and internal combustion engines and compressors. An indicator chart records the pressure in the cylinder versus the volume swept by the piston, throughout the two or four strokes of the piston which constitute the engine, or compressor, cycle. The indicator diagram is used to calculate the work done and the power produced in an engine cylinder or used in a compressor cylinder.
