History of artThe history of art focuses on objects made by humans for any number of spiritual, narrative, philosophical, symbolic, conceptual, documentary, decorative, and even functional and other purposes, but with a primary emphasis on its aesthetic visual form. Visual art can be classified in diverse ways, such as separating fine arts from applied arts; inclusively focusing on human creativity; or focusing on different media such as architecture, sculpture, painting, film, photography, and graphic arts.
Art of EuropeThe art of Europe, also known as Western art, encompasses the history of visual art in Europe. European prehistoric art started as mobile Upper Paleolithic rock and cave painting and petroglyph art and was characteristic of the period between the Paleolithic and the Iron Age. Written histories of European art often begin with the Aegean civilizations, dating from the 3rd millennium BC. However a consistent pattern of artistic development within Europe becomes clear only with Ancient Greek art, which was adopted and transformed by Rome and carried; with the Roman Empire, across much of Europe, North Africa and Western Asia.
Ancient artAncient art refers to the many types of art produced by the advanced cultures of ancient societies with different forms of writing, such as those of ancient China, India, Mesopotamia, Persia, Palestine, Egypt, Greece, and Rome. The art of pre-literate societies is normally referred to as prehistoric art and is not covered here. Although some pre-Columbian cultures developed writing during the centuries before the arrival of Europeans, on grounds of dating these are covered at pre-Columbian art and articles such as Maya art, Aztec art, and Olmec art.
African artAfrican art describes the modern and historical paintings, sculptures, installations, and other visual culture from native or indigenous Africans and the African continent. The definition may also include the art of the African diasporas, such as: African-American, Caribbean or art in South American societies inspired by African traditions. Despite this diversity, there are unifying artistic themes present when considering the totality of the visual culture from the continent of Africa.
Art of ancient EgyptAncient Egyptian art refers to art produced in ancient Egypt between the 6th millennium BC and the 4th century AD, spanning from Prehistoric Egypt until the Christianization of Roman Egypt. It includes paintings, sculptures, drawings on papyrus, faience, jewelry, ivories, architecture, and other art media. It was a conservative tradition whose style changed very little over time. Much of the surviving examples comes from tombs and monuments, giving insight into the ancient Egyptian afterlife beliefs.
Wind powerWind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity generation. Today, wind power is generated almost completely with wind turbines, generally grouped into wind farms and connected to the electrical grid. In 2022, wind supplied over 2000 TWh of electricity, which was over 7% of world electricity and about 2% of world energy.
Demand responseDemand response is a change in the power consumption of an electric utility customer to better match the demand for power with the supply. Until the 21st century decrease in the cost of pumped storage and batteries electric energy could not be easily stored, so utilities have traditionally matched demand and supply by throttling the production rate of their power plants, taking generating units on or off line, or importing power from other utilities.
PulsejetA pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need to have air forced into its inlet, typically by forward motion). The best known example may be the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb. Pulsejet engines are a lightweight form of jet propulsion, but usually have a poor compression ratio, and hence give a low specific impulse.
Jet engineA jet engine is a type of reaction engine, discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition may include rocket, water jet, and hybrid propulsion, the term typically refers to an internal combustion air-breathing jet engine such as a turbojet, turbofan, ramjet, or pulse jet. In general, jet engines are internal combustion engines.
Electronic oscillatorAn electronic oscillator is an electronic circuit that produces a periodic, oscillating or alternating current (AC) signal, usually a sine wave, square wave or a triangle wave, powered by a direct current (DC) source. Oscillators are found in many electronic devices, such as radio receivers, television sets, radio and television broadcast transmitters, computers, computer peripherals, cellphones, radar, and many other devices.
