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Nuclear Pasta
In astrophysics and nuclear physics, nuclear pasta is a theoretical type of degenerate matter that is postulated to exist within the crusts of neutron stars. If it exists, nuclear pasta would be the strongest material in the universe. Between the surface of a neutron star and the quark–gluon plasma at the core, at matter densities of 1014 g/cm3, nuclear attraction and Coulomb repulsion forces are of similar magnitude. The competition between the forces leads to the formation of a variety of complex structures assembled from neutrons and protons. Astrophysicists call these types of structures ''nuclear pasta'' because the geometry of the structures resembles various types of pasta. Formation Neutron stars form as remnants of massive stars after a supernova event. Unlike their progenitor star, neutron stars do not consist of a gaseous plasma. Rather, the intense gravitational attraction of the compact mass overcomes the electron degeneracy pressure and causes electron captur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Star Cross Section
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. Their properties and interactions are described by nuclear physics. Protons and neutrons are not elementary particles; each is composed of three quarks. The chemical properties of an atom are mostly determined by the configuration of electrons that orbit the atom's heavy nucleus. The electron configuration is determined by the charge of the nucleus, which is determined by the number of protons, or atomic number. The number of neutrons is the neutron number. Neutrons do not affect the electron configuration, but the sum of atomic and neutron numbers is the mass of the nucleus. Atoms of a chemical element that di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Academies Press
The US National Academies Press (NAP) was created to publish the reports issued by the National Academies of Sciences, Engineering, and Medicine, the National Academy of Engineering, the National Academy of Medicine, and the National Research Council. It publishes nearly 200 books a year on a wide range of topics in the sciences. The NAP's stated mission is seemingly self-contradictory: to disseminate as widely as possible the works of the National Academies of Sciences, Engineering, and Medicine, and to be financially self-sustaining through sales. This mission has led to great experimentation in openness regarding online publishing. The National Academy Press (as it was known in 1993) was the first self-sustaining publisher to make its material available on the Web, for free, in an open access model. By 1997, 1000 reports were available as sequential page images (starting with i, then ii, then iii, then iv...), with a minimal navigational envelope. Their experience up to 1998 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Mass
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of the Sun. This equates to about two nonillion (short scale), two quintillion (long scale) kilograms or 2000 quettagrams: The solar mass is about times the mass of Earth (), or times the mass of Jupiter (). History of measurement The value of the gravitational constant was first derived from measurements that were made by Henry Cavendish in 1798 with a torsion balance. The value he obtained differs by only 1% from the modern value, but was not as precise. The diurnal parallax of the Sun was accurately measured during the transits of Venus in 1761 and 1769, yielding a value of (9 arcseconds, compared to the present value of ). From the value of the diurnal parallax, one can determine the distance to the Sun from the geometry o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (mathematics)
In mathematics, homology is a general way of associating a sequence of algebraic objects, such as abelian groups or modules, with other mathematical objects such as topological spaces. Homology groups were originally defined in algebraic topology. Similar constructions are available in a wide variety of other contexts, such as abstract algebra, groups, Lie algebras, Galois theory, and algebraic geometry. The original motivation for defining homology groups was the observation that two shapes can be distinguished by examining their holes. For instance, a circle is not a disk because the circle has a hole through it while the disk is solid, and the ordinary sphere is not a circle because the sphere encloses a two-dimensional hole while the circle encloses a one-dimensional hole. However, because a hole is "not there", it is not immediately obvious how to define a hole or how to distinguish different kinds of holes. Homology was originally a rigorous mathematical method for defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swiss Cheese (North America)
Swiss cheese is any variety of cheese that resembles Emmental cheese, a yellow, medium-hard cheese that originated in the area around Emmental, Switzerland. It is classified as a Swiss-type or Alpine cheese. Some types of Swiss cheese have a distinctive appearance, as the blocks or rounds of the cheese are riddled with holes known as "eyes". Swiss cheese without eyes is known as "blind". Swiss cheese is now manufactured in many countries, including the United States, Finland, Estonia, and Ireland. It is sometimes made with pasteurized or part-skim milk, unlike the original from Switzerland made with raw milk. The United States Department of Agriculture uses the terms Swiss cheese and Emmentaler cheese interchangeably. In Australia, both terms are used, along with Swiss-style cheese, in some cases differentiating the two. The term Swiss cheese is sometimes used in India, although it is also often referred to as Emmental, which is the more common name in Europe. Production Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bucatini
Bucatini (), also known as perciatelli (), are a thick spaghetti-like pasta with a hole running through the center. They are common throughout Lazio, particularly Rome. The similar ziti are long hollow rods which are also smooth in texture and have square-cut edges; "cut ziti" are ziti cut into shorter tubes. There is also a wider version of ziti, zitoni . Name The name comes from the Italian ''buco'', meaning "hole", while ''wikt:bucato#Italian, bucato'' or its Neapolitan language variant ''perciato'' means "pierced". Composition and use Bucatini are a tubed pasta made of hard durum wheat flour and water. Its length is with a diameter. The average cooking time is nine minutes. In Italian cuisine, bucatini are served with buttery sauces, guanciale, vegetables, cheese, eggs, and anchovy, anchovies or sardines. One of the most common sauces to serve with bucatini is the Amatriciana sauce, ''bucatini all'amatriciana''. It is traditionally made with guanciale, a type of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lasagna
Lasagna (, also , also known as lasagne, ) is a type of pasta, possibly one of the oldest types, made of very wide, flat sheets. Either term can also refer to an Italian dish made of stacked layers of lasagna alternating with fillings such as ragù (ground meats and tomato sauce), vegetables, cheeses (which may include ricotta, mozzarella, and parmesan), and seasonings and spices. The dish may be topped with grated cheese, which becomes melted after baking. Typically cooked pasta is assembled with the other ingredients and then baked in an oven. The resulting baked pasta is cut into single-serving square portions. Origins and history Lasagna originated in Italy during the Middle Ages. The oldest transcribed text about lasagna appears in 1282 in the ''Memoriali Bolognesi'' ("Bolognesi Memorials"), in which lasagna was mentioned in a poem transcribed by a Bolognese notary; while the first recorded recipe was set down in the early 14th-century ''Liber de Coquina'' (''The Book of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spaghetti
Spaghetti () is a long, thin, solid, cylindrical pasta.spaghetti Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. (accessed: 3 June 2008). It is a of traditional . Like other pasta, spaghetti is made of milled and and sometimes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnocchi
Gnocchi ( , , ; singular ''gnocco'') are a varied family of dumpling in Italian cuisine. They are made of small lumps of dough most traditionally composed of a simple combination of wheat flour, egg, salt, and potato. Variations of the dish supplement the simple recipe with flavour additives, such as semolina flour, cheese, breadcrumbs, cornmeal or similar ingredients, and possibly including herbs, vegetables, and other ingredients. Base ingredients may be substituted with alternatives such as sweet potatoes for potatoes or rice flour for wheat flour. Such variations are often considered to be non-traditional. Gnocchi are commonly cooked in salted boiling water and then dressed with various sauces. They are usually eaten as a first course (''primo piatto'') as an alternative to soups (''minestre'') or pasta, but they can also be served as a ''contorno'' (side dish) to some main courses. Common accompaniments of gnocchi include melted butter with sage, pesto, as well as vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleon
In physics and chemistry, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus. The number of nucleons in a nucleus defines the atom's mass number (nucleon number). Until the 1960s, nucleons were thought to be elementary particles, not made up of smaller parts. Now they are known to be composite particles, made of three quarks bound together by the strong interaction. The interaction between two or more nucleons is called internucleon interaction or nuclear force, which is also ultimately caused by the strong interaction. (Before the discovery of quarks, the term "strong interaction" referred to just internucleon interactions.) Nucleons sit at the boundary where particle physics and nuclear physics overlap. Particle physics, particularly quantum chromodynamics, provides the fundamental equations that describe the properties of quarks and of the strong interaction. These equations describe quantitatively how quarks can bind toget ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charge Distribution
In electromagnetism, charge density is the amount of electric charge per unit length, surface area, or volume. Volume charge density (symbolized by the Greek letter ρ) is the quantity of charge per unit volume, measured in the SI system in coulombs per cubic meter (C⋅m−3), at any point in a volume. Surface charge density (σ) is the quantity of charge per unit area, measured in coulombs per square meter (C⋅m−2), at any point on a surface charge distribution on a two dimensional surface. Linear charge density (λ) is the quantity of charge per unit length, measured in coulombs per meter (C⋅m−1), at any point on a line charge distribution. Charge density can be either positive or negative, since electric charge can be either positive or negative. Like mass density, charge density can vary with position. In classical electromagnetic theory charge density is idealized as a ''continuous'' scalar function of position \boldsymbol, like a fluid, and \rho(\boldsymbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
