Fluid powerFluid power is the use of fluids under pressure to generate, control, and transmit power. Fluid power is conventionally subdivided into hydraulics (using a liquid such as mineral oil or water) and pneumatics (using a gas such as compressed air or other gases). Although steam is also a fluid, steam power is usually classified separately from fluid power (implying hydraulics or pneumatics). Compressed-air and water-pressure systems were once used to transmit power from a central source to industrial users over extended geographic areas; fluid power systems today are usually within a single building or mobile machine.
Gas-discharge lampGas-discharge lamps are a family of artificial light sources that generate light by sending an electric discharge through an ionized gas, a plasma. Typically, such lamps use a noble gas (argon, neon, krypton, and xenon) or a mixture of these gases. Some include additional substances, such as mercury, sodium, and metal halides, which are vaporized during start-up to become part of the gas mixture. Single-ended self-starting lamps are insulated with a mica disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap.
Eddy (fluid dynamics)In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers.
Dielectric barrier dischargeDielectric-barrier discharge (DBD) is the electrical discharge between two electrodes separated by an insulating dielectric barrier. Originally called silent (inaudible) discharge and also known as ozone production discharge or partial discharge, it was first reported by Ernst Werner von Siemens in 1857. The process normally uses high voltage alternating current, ranging from lower RF to microwave frequencies. However, other methods were developed to extend the frequency range all the way down to the DC.
Hydraulic headHydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum. It is usually measured as a liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer. In an aquifer, it can be calculated from the depth to water in a piezometric well (a specialized water well), and given information of the piezometer's elevation and screen depth. Hydraulic head can similarly be measured in a column of water using a standpipe piezometer by measuring the height of the water surface in the tube relative to a common datum.
CurveIn mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that appeared more than 2000 years ago in Euclid's Elements: "The [curved] line is [...] the first species of quantity, which has only one dimension, namely length, without any width nor depth, and is nothing else than the flow or run of the point which [...
Andrea AppianiAndrea Appiani (31 May 1754 - 8 November 1817) was an Italian neoclassical painter. Born in Milan, it had been intended that he follow his father's career in medicine but instead entered the private academy of the painter Carlo Maria Giudici (1723–1804) where he received instruction in drawing, copying mainly from sculpture and prints. From there, he then joined the class of the fresco painter Antonio de' Giorgi, which was held at the Ambrosiana picture gallery in Milan.
Algebraic curveIn mathematics, an affine algebraic plane curve is the zero set of a polynomial in two variables. A projective algebraic plane curve is the zero set in a projective plane of a homogeneous polynomial in three variables. An affine algebraic plane curve can be completed in a projective algebraic plane curve by homogenizing its defining polynomial. Conversely, a projective algebraic plane curve of homogeneous equation h(x, y, t) = 0 can be restricted to the affine algebraic plane curve of equation h(x, y, 1) = 0.
Contardo FerriniContardo Ferrini (5 April 1859 – 17 October 1902) was a noted Italian jurist and legal scholar. He was also a fervent Roman Catholic, who lived a devout life of prayer and service to the poor. He has been beatified by the Catholic Church. He was born on 5 April 1859 in Milan, Italy, to Rinaldo Ferrini and Luigia Buccellati. He was baptized at the same baptismal font where Frédéric Ozanam, also a native of Milan, had been baptized 46 years prior. After receiving his First Holy Communion at the age of twelve, he joined the Confraternity of the Blessed Sacrament.
Ignacio Rodríguez IturbeIgnacio Rodríguez Iturbe (8 March 1942 – 28 September 2022) was a Venezuelan hydrologist who was a professor at Texas A&M University. Rodríguez Iturbe was born in Maracaibo, Zulia State in 1942. He graduated from the University of Zulia as a civil engineer and did graduate studies at Caltech, earning his PhD at Colorado State University in 1967. Rodríguez Iturbe taught at many universities, including the University of Zulia, MIT, Texas A&M, Princeton University and the University of Iowa.
Daniele ArchibugiDaniele Archibugi (born 17 July 1958 in Rome, Italy) is an Italian economic and political theorist. He works on the economics and policy of innovation and technological change, on the political theory of international relations and on political and technological globalisation. Archibugi graduated with an Economics degree at the University of Rome "La Sapienza" with Federico Caffè, and obtained a D.Phil. degree at SPRU of the University of Sussex under the mentorship of Christopher Freeman and Keith Pavitt.
Canadian DimensionCanadian Dimension (CD) is a Canadian left-wing magazine founded in 1963 by Cy Gonick and published in Winnipeg, Manitoba. In 2019, CD transitioned to a digital publication "as a springboard to a lively role in the 21st century resurgence of radical socialist thinking and organizing." Canadian Dimension is a forum for left-wing political thought, opinion, and analysis that ranges from New Democratic Party–style social democracy to libertarian socialism. The magazine was founded in 1963 by Cy Gonick, and a collective took over editorial responsibility in 1975.
