X-rayX-ray radiation, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3e16Hz to 3e19Hz) and energies in the range 124 keV to 145 eV, respectively. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays.
X-ray tubeAn X-ray tube is a vacuum tube that converts electrical input power into X-rays. The availability of this controllable source of X-rays created the field of radiography, the imaging of partly opaque objects with penetrating radiation. In contrast to other sources of ionizing radiation, X-rays are only produced as long as the X-ray tube is energized. X-ray tubes are also used in CT scanners, airport luggage scanners, X-ray crystallography, material and structure analysis, and for industrial inspection.
Proposal (business)A business proposal is a written offer from a seller to a prospective sponsor. Business proposals are often a key step in the complex sales process—i.e., whenever a buyer considers more than price in a purchase. When one person signifies to another their willingness to do or to abstain from doing anything with a view to obtaining the assent of the other to such act or abstinence, they are said to make a proposal. A proposal puts the buyer's requirements in a context that favors the seller's products and services, and educates the buyer about the seller's capability to satisfy their needs.
Logarithmic meanIn mathematics, the logarithmic mean is a function of two non-negative numbers which is equal to their difference divided by the logarithm of their quotient. This calculation is applicable in engineering problems involving heat and mass transfer. The logarithmic mean is defined as: for the positive numbers x, y. The logarithmic mean of two numbers is smaller than the arithmetic mean and the generalized mean with exponent one-third but larger than the geometric mean, unless the numbers are the same, in which case all three means are equal to the numbers.
Request for proposalA request for proposal (RFP) is a document that solicits a proposal, often made through a bidding process, by an agency or company interested in procurement of a commodity, service, or valuable asset, to potential suppliers to submit business proposals. An RFP is used where the request requires technical expertise, specialized capability, or where the product or service being requested does not yet exist, and the proposal may require research and development to create whatever is being requested.
X-ray astronomyX-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy uses a type of space telescope that can see x-ray radiation which standard optical telescopes, such as the Mauna Kea Observatories, cannot.
Logarithmic derivativeIn mathematics, specifically in calculus and complex analysis, the logarithmic derivative of a function f is defined by the formula where is the derivative of f. Intuitively, this is the infinitesimal relative change in f; that is, the infinitesimal absolute change in f, namely scaled by the current value of f. When f is a function f(x) of a real variable x, and takes real, strictly positive values, this is equal to the derivative of ln(f), or the natural logarithm of f.
20202020 was heavily defined by the COVID-19 pandemic, which led to global social and economic disruption, mass cancellations and postponements of events, worldwide lockdowns and the largest economic recession since the Great Depression in the 1930s. Geospatial World also called 2020 "the worst year in terms of climate change" in part due to major climate disasters worldwide, including major bushfires in Australia and the western United States, as well as extreme tropical cyclone activity affecting large parts of North America.
Radius of convergenceIn mathematics, the radius of convergence of a power series is the radius of the largest disk at the center of the series in which the series converges. It is either a non-negative real number or . When it is positive, the power series converges absolutely and uniformly on compact sets inside the open disk of radius equal to the radius of convergence, and it is the Taylor series of the analytic function to which it converges.
FC VSS KošiceFC VSS Košice, formerly 1. FC Košice, was a Slovak football club based in Košice which played in the Slovak 2. Liga during the 2016–17 season. The club officially ceased operations on 27 July 2017. The club, founded in 1903, has won the Slovak League twice, the Slovak Cup five times and the Czechoslovak Cup once. The most successful eras of the club were in the 1970s and 1990s which they spent mostly in the top tier of Czechoslovak and Slovak Football. Two of the UEFA Euro 1976 champions namely Dušan Galis and Jaroslav Pollák played for Košice.
RAF JurbyRoyal Air Force Station Jurby or more simply RAF Jurby is a former Royal Air Force station built in the north west of the Isle of Man. It was opened in 1939 on of land acquired by the Air Ministry in 1937, under the control of No. 29 Group, RAF. During the Second World War the station was used for training as No. 5 Armament Training Station, No. 5 Air Observer School, No. 5 Bombing & Gunnery School and the No. 5 Air Navigation & Bombing School. In addition RAF Jurby also played host to a variety of operational squadrons.
