Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found in the molecular H2 form. To exist as a liquid, H2 must be cooled below hydrogen's critical point of 33 K. However, for hydrogen to be in a liquid state without boiling at atmospheric pressure, it needs to be cooled to 20.28 K. One common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. Liquid hydrogen is used as a concentrated form of hydrogen storage; as in any gas, storing it as liquid takes less space than storing it as a gas at normal temperature and pressure. However, the liquid density is low compared to other common fuels. Once liquefied, it can be maintained as a liquid in thermally insulated containers. There are two spin isomers of hydrogen. In 1885, Zygmunt Florenty Wróblewski published hydrogen's critical temperature as 33 K. Hydrogen was liquefied by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask; the first synthesis of the stable isomer form of liquid hydrogen, was achieved by Paul Harteck and Karl Friedrich Bonhoeffer in 1929.
The two nuclei in a dihydrogen molecule can have two different spin states. Parahydrogen, in which the two nuclear spins are antiparallel, is more stable than orthohydrogen, in which the two are parallel. At room temperature, gaseous hydrogen is in the ortho isomeric form due to thermal energy, but an ortho-enriched mixture is only metastable when liquified at low temperature, it undergoes an exothermic reaction to become the para isomer, with enough energy released as heat to cause some of the liquid to boil. To prevent loss of the liquid during long-term storage, it is therefore intentionally converted to the para isomer as part of the production process using a catalyst such as iron oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromium oxide, or some nickel compounds. Liquid hydrogen is a common liquid rocket fuel for rocketry applications — both NASA and the United States Air Force operate a large number of liquid hydrogen tanks with an individual capacity up to 3.8 million liters.
In most rocket engines fueled by liquid hydrogen, it first cools the nozzle and other parts before being mixed with the oxidizer — liquid oxygen — and burned to produce water with traces of ozone and hydrogen peroxide. Practical H2–O2 rocket engines run fuel-rich so that the exhaust contains some unburned hydrogen; this reduces nozzle erosion. It reduces the molecular weight of the exhaust, which can increase specific impulse, despite the incomplete combustion. Liquid hydrogen can be used as the fuel for an internal combustion fuel cell. Various submarines and concept hydrogen vehicles have been built using this form of hydrogen. Due to its similarity, builders can sometimes modify and share equipment with systems designed for liquefied natural gas. However, because of the lower volumetric energy, the hydrogen volumes needed for combustion are large. Unless direct injection is used, a severe gas-displacement effect hampers maximum breathing and increases pumping losses. Liquid hydrogen is used to cool neutrons to be used in neutron scattering.
Since neutrons and hydrogen nuclei have similar masses, kinetic energy exchange per interaction is maximum. Superheated liquid hydrogen was used in many bubble chamber experiments; the first thermonuclear bomb, Ivy Mike, used liquid deuterium, for nuclear fusion. The product of its combustion with oxygen alone is water vapor, which can be cooled with some of the liquid hydrogen. Since water is considered harmless to the environment, an engine burning it can be considered "zero emissions." In aviation, water vapor emitted in the atmosphere contributes to global warming. Liquid hydrogen has a much higher specific energy than gasoline, natural gas, or diesel; the density of liquid hydrogen is only 70.99 g/L, a relative density of just 0.07. Although the specific energy is more than twice that of other fuels, this gives it a remarkably low volumetric energy density, many fold lower. Liquid hydrogen requires cryogenic storage technology such as special thermally insulated containers and requires special handling common to all cryogenic fuels.
This is more severe than liquid oxygen. With thermally insulated containers it is difficult to keep such a low temperature, the hydrogen will leak away, it shares many of the same safety issues as other forms of hydrogen, as well as being cold enough to liquefy, or solidify atmospheric oxygen, which can be an explosion hazard. The triple point of hydrogen is at 13.81 K 7.042 kPa. Due to its cold temperatures, liquid hydrogen is a hazard for cold burns. Apart from that, elemental hydrogen as a liquid is biologically inert and its only human health hazard as a vapor is displacement of oxygen, resulting in asphyxiation; because of its flammability, liquid hydrogen should be kept away from heat or flame unless ignition is intended
W and Z bosons
The W and Z bosons are together known as the weak or more as the intermediate vector bosons. These elementary particles mediate the weak interaction; the W bosons have either a positive or negative electric charge of 1 elementary charge and are each other's antiparticles. The Z boson is its own antiparticle; the three particles have a spin of 1. The W bosons have a magnetic moment. All three of these particles are short-lived, with a half-life of about 3×10−25 s, their experimental discovery was a triumph for what is now known as the Standard Model of particle physics. The W bosons are named after the weak force; the physicist Steven Weinberg named the additional particle the "Z particle", gave the explanation that it was the last additional particle needed by the model. The W bosons had been named, the Z bosons have zero electric charge; the two W bosons are verified mediators of neutrino emission. During these processes, the W boson charge induces electron or positron emission or absorption, thus causing nuclear transmutation.
The Z boson is not involved in the emission of electrons and positrons. The Z boson mediates the transfer of momentum and energy when neutrinos scatter elastically from matter; such behavior is as common as inelastic neutrino interactions and may be observed in bubble chambers upon irradiation with neutrino beams. Whenever an electron is observed as a new free particle moving with kinetic energy, it is inferred to be a result of a neutrino interacting directly with the electron, since this behavior happens more when the neutrino beam is present. In this process, the neutrino strikes the electron and scatters away from it, transferring some of the neutrino's momentum to the electron; because neutrinos are neither affected by the strong force nor the electromagnetic force, because the gravitational force between subatomic particles is negligible, such an interaction can only happen via the weak force. Since such an electron is not created from a nucleon, is unchanged except for the new force impulse imparted by the neutrino, this weak force interaction between the neutrino and the electron must be mediated by an electromagnetically neutral, weak-force boson particle.
Thus, this interaction requires a Z boson. These bosons are among the heavyweights of the elementary particles. With masses of 80.4 GeV/c2 and 91.2 GeV/c2 the W and Z bosons are 80 times as massive as the proton – heavier than entire iron atoms. Their high masses limit the range of the weak interaction. By way of contrast, the photon is the force carrier of the electromagnetic force and has zero mass, consistent with the infinite range of electromagnetism. All three bosons have particle spin s = 1; the emission of a W+ or W− boson either raises or lowers the electric charge of the emitting particle by one unit, alters the spin by one unit. At the same time, the emission or absorption of a W boson can change the type of the particle – for example changing a strange quark into an up quark; the neutral Z boson cannot change the electric charge of any particle, nor can it change any other of the so-called "charges". The emission or absorption of a Z boson can only change the spin and energy of the other particle.
The W and Z bosons are carrier particles that mediate the weak nuclear force, much as the photon is the carrier particle for the electromagnetic force. The W bosons are best known for their role in nuclear decay. Consider, for example, the beta decay of cobalt-60. 6027Co → 6028Ni+ + e− + νeThis reaction does not involve the whole cobalt-60 nucleus, but affects only one of its 33 neutrons. The neutron is converted into a proton while emitting an electron and an electron antineutrino: n0 → p+ + e− + νeAgain, the neutron is not an elementary particle but a composite of an up quark and two down quarks, it is in fact one of the down quarks that interacts in beta decay, turning into an up quark to form a proton. At the most fundamental level the weak force changes the flavour of a single quark: d → u + W−which is followed by decay of the W− itself: W− → e− + νe The Z boson is its own antiparticle. Thus, all of its flavour quantum numbers and charges are zero; the exchange of a Z boson between particles, called a neutral current interaction, therefore leaves the interacting particles unaffected, except for a transfer of momentum.
Z boson interactions involving neutrinos have distinctive signatures: They provide the only known mechanism for elastic scattering of neutrinos in matter. The first prediction of Z bosons was made by Brazilian physicist José Leite Lopes in 1958, by devising an equation which showed the analogy of the weak nuclear interactions with electromagnetism. Steve Weinberg, Sheldon Glashow and Abdus Salam used these results to develop the electroweak unification, in 1973. Weak neutral currents via Z boson exchange were confirmed shortly thereafter, in a neutrino experiment in the Gargamelle bubble chamber at CERN. Following the spectacular success of quantum electrodynamics in the 1950s, attempts were undertaken to formulate a similar theory of the weak nuclear force; this culminated around 1968 in a
Donald A. Glaser
Donald Arthur Glaser was an American physicist and the winner of the 1960 Nobel Prize in Physics for his invention of the bubble chamber used in subatomic particle physics. Born in Cleveland, Glaser completed his Bachelor of Science degree in physics and mathematics from Case School of Applied Science in 1946, he completed his Ph. D. in physics from the California Institute of Technology in 1949. Glaser accepted a position as an instructor at the University of Michigan in 1949, was promoted to professor in 1957, he joined the faculty of the University of California at Berkeley, in 1959, as a Professor of Physics. During this time his research concerned short-lived elementary particles; the bubble chamber enabled him to observe the lifetimes of the particles. Starting in 1962, Glaser changed his field of research to molecular biology, starting with a project on ultraviolet-induced cancer. In 1964, he was given the additional title of Professor of Molecular Biology. Glaser's position was Professor of Neurobiology in the Graduate School.
Donald Glaser was born on September 21, 1926, in Cleveland, Ohio, to Russian Jewish immigrants and William J. Glaser, a businessman, he enjoyed music and played the piano and viola. He went to Cleveland Heights High School, where he became interested in physics as a means to understand the physical world, he died in his sleep at the age of 86 on February 2013 in Berkeley, California. He is survived by his wife, Lynn Glaser, his daughter, Louise Glaser, his son, William Glaser, his grandson Aaron Cohen, granddaughters Emily and Katherine Schreiner and Caroline and Julia Glaser. Glaser attended Case School of Applied Science, where he completed his bachelor's degree in physics and mathematics in 1946. During the course of his education there, he became interested in particle physics, he played viola in the Cleveland Philharmonic while at Case, taught mathematics classes at the college after graduation. He continued on to the California Institute of Technology, where he pursued his Ph. D. in physics.
His interest in particle physics led him to work with Nobel laureate Carl David Anderson, studying cosmic rays with cloud chambers. He preferred the accessibility of cosmic ray research over that of nuclear physics. While at Caltech he learned to design and build the equipment he needed for his experiments, this skill would prove to be useful throughout his career, he attended molecular genetics seminars led by Nobel laureate Max Delbrück. Glaser completed his doctoral thesis, The Momentum Distribution of Charged Cosmic Ray Particles Near Sea Level, after starting as an instructor at the University of Michigan in 1949, he received his Ph. D. from Caltech in 1950, he was promoted to Professor at Michigan in 1957. While teaching at Michigan, Glaser began to work on experiments that led to the creation of the bubble chamber, his experience with cloud chambers at Caltech had shown him that they were inadequate for studying elementary particles. In a cloud chamber, particles pass through gas and collide with metal plates that obscure the scientists' view of the event.
The cloud chamber needs time to reset between recording events and cannot keep up with accelerators' rate of particle production. He experimented with using superheated liquid in a glass chamber. Charged particles would leave a track of bubbles as they passed through the liquid, their tracks could be photographed, he created the first bubble chamber with ether. He experimented with hydrogen while visiting the University of Chicago, showing that hydrogen would work in the chamber, it has been claimed that Glaser was inspired to his invention by the bubbles in a glass of beer. His new invention was ideal for use with high-energy accelerators, so Glaser traveled to Brookhaven National Laboratory with some students to study elementary particles using the accelerator there; the images that he created with his bubble chamber brought recognition of the importance of his device, he was able to get funding to continue experimenting with larger chambers. Glaser was recruited by Nobel laureate Luis Alvarez, working on a hydrogen bubble chamber at the University of California at Berkeley.
Glaser accepted an offer to become a Professor of Physics there in 1959. Glaser was awarded the 1960 Nobel Prize for Physics for the invention of the bubble chamber, his invention allowed scientists to observe what happens to high-energy beams from an accelerator, thus paving the way for many important discoveries. After winning the Nobel Prize, Glaser began to think about switching from physics into a new field, he wanted to concentrate on science, found that as the experiments and equipment grew larger in scale and cost, he was doing more administrative work. He anticipated that the ever-more-complex equipment would cause consolidation into fewer sites and would require more travel for physicists working in high-energy physics. Recalling his interest in molecular genetics that began at Caltech, Glaser began to study biology, he attended biology seminars there. He spent a semester in Copenhagen with Ole Maaloe, the prominent Danish molecular biologist, he worked in UC Berkeley's Virus Lab, doing experiments with bacterial phages and mammalian cells.
He studied the development of cancer cells, in particular the skin cancer xeroderma pigmentosum. As with the bubble chamber
The Bevatron was a particle accelerator — a weak-focusing proton synchrotron — at Lawrence Berkeley National Laboratory, U. S. which began operating in 1954. The antiproton was discovered there in 1955, resulting in the 1959 Nobel Prize in physics for Emilio Segrè and Owen Chamberlain, it accelerated protons into a fixed target, was named for its ability to impart energies of billions of eV. At the time the Bevatron was designed, it was suspected but not known, that each particle had a corresponding anti-particle of opposite charge, identical in all other respects, a property known as charge symmetry; the anti-electron, or positron had been first observed in the early 1930s, theoretically understood as a consequence of the Dirac equation at about the same time. Following World War II, positive and negative muons and pions were observed in cosmic-ray interactions seen in cloud chambers and stacks of nuclear photographic emulsions; the Bevatron was built to be energetic enough to create antiprotons, thus test the hypothesis that every particle has a corresponding anti-particle.
And, in 1955, the antiproton was discovered using the Bevatron. The antineutron was discovered soon thereafter by Oreste Piccioni and co-workers at the Bevatron. Confirmation of the charge symmetry conjecture in 1955 led to the Nobel Prize for physics being awarded to Emilio Segrè and Owen Chamberlain in 1959. Shortly after the Bevatron came into use, it was recognized that parity was not conserved in the weak interactions, which led to resolution of the tau-theta puzzle, the understanding of strangeness, the establishment of CPT symmetry as a basic feature of relativistic quantum field theories. In order to create antiprotons in collisions with nucleons in a stationary target while conserving both energy and momentum, a proton beam energy of 6.2 GeV is required. At the time it was built, there was no known way to confine a particle beam to a narrow aperture, so the beam space was about four square feet in cross section; the combination of beam aperture and energy required a huge, 10,000 ton iron magnet, a large vacuum system.
A large motor-generator system was used to ramp up the magnetic field for each cycle of acceleration. At the end of each cycle, after the beam was used or extracted, the large magnetic field energy was returned to spin up the motor, used as a generator to power the next cycle, conserving energy; the characteristic rising and falling, sound of the motor-generator system could be heard in the entire complex when the machine was in operation. In the years following the antiproton discovery, much pioneering work was done here using beams of protons extracted from the accelerator proper, to hit targets and generate secondary beams of elementary particles, not only protons but neutrons, pions, "strange particles", many others; the extracted particle beams, both the primary protons and secondaries, could in turn be passed for further study through various targets and specialized detectors, notably the liquid hydrogen bubble chamber. Many thousands of particle interactions, or "events", were photographed and studied in detail with an automated system of large measuring machines allowing human operators to mark points along the particle tracks and punch their coordinates into IBM cards, using a foot pedal.
The cards decks were analyzed by early-generation computers, which reconstructed the three-dimensional tracks through the magnetic fields, computed the momenta and energy of the particles. Computer programs complex for their time fitted the track data associated with a given event to estimate the energies and identities of the particles produced; this period, when hundreds of new particles and excited states were revealed, marked the beginning of a new era in elementary particle physics. Luis Alvarez inspired and directed much of this work, for which he received the Nobel Prize in physics in 1968; the Bevatron received a new lease on life in 1971, when it was joined to the SuperHILAC linear accelerator as an injector for heavy ions. The combination was conceived by Albert Ghiorso, it could accelerate a wide range of stable nuclei to relativistic energies. It was decommissioned in 1993; the next generation of accelerators used "strong focusing", required much smaller apertures, thus much cheaper magnets.
The CERN PS and the Brookhaven National Laboratory AGS were the first next-generation machines, with an aperture an order of magnitude less in both transverse directions, reaching 30 GeV proton energy, yet with a less massive magnet ring. For comparison, the circulating beams in the Large Hadron Collider, with ~11,000 times higher energy and enormously higher intensity than the Bevatron, are confined to a space on the order of 1 mm in cross-section, focused down to 16 micrometres at the intersection collision regions, while the field of the bending magnets is only about five times higher; the demolition of the Bevatron began in 2009 by Clauss Construction of Lakeside CA and was completed in 2011. Alternating Gradient Synchrotron: 33 GeV strong-focusing synchrotron, next step after Bevatron Tevatron: Fermi Lab accelerator, 1 TeV proton-antiproton collider, largest current US machine History of the Bevatron "The Bevatron" E. J. Lofgren historical retrospective account. Pictures of the Bevatron Shu
The Nobel Foundation is a private institution founded on 29 June 1900 to manage the finances and administration of the Nobel Prizes. The Foundation is based on the last will of the inventor of dynamite, it holds Nobel Symposia on important breakthroughs in science and topics of cultural or social significance. Alfred Bernhard Nobel, born on 21 October 1833 in Stockholm Sweden, was a chemist, innovator, armaments manufacturer and the inventor of dynamite, he owned Bofors, a major armaments manufacturer, which he had redirected from its original business as an iron and steel mill. Nobel held 355 different patents. Nobel amassed a sizeable personal fortune during his lifetime, thanks to this invention. In 1896 Nobel died of a stroke in his villa in San Remo, Italy where he had lived out the last years of his life. Nobel's will expressed a request, to the surprise of many, that his money be used for prizes in physics, peace, physiology or medicine and literature. Though Nobel wrote several wills during his lifetime, the last was written a little over a year before he died, signed at the Swedish-Norwegian Club in Paris on 27 November 1895.
Nobel bequeathed 94% of his total assets, 31 million Swedish kronor, to establish and endow the five Nobel Prizes. The executors of his will were Ragnar Sohlman and Rudolf Lilljequist who formed the Nobel Foundation to take care of Nobel's fortune and organize the prizes. Although Nobel's will established the prizes, his plan was incomplete and, because of various other hurdles, it took five years before the Nobel Foundation could be established and the first prizes could be awarded on 10 December 1901 to, among others, Wilhelm Conrad Röntgen; as of 31 December 2015, the assets controlled by the Nobel Foundation amounted to 4.065 billion Swedish kronor. The Nobel Foundation was founded as a private organisation on 29 June 1900 to manage the finances and administration of the Nobel Prizes, it is based on testament. At the time Nobel's will led to much specticism and criticism and thus it was not until 26 April 1897 that his will was approved by the Storting. Soon thereafter they appointed the members of the Norwegian Nobel Committee, to award the Peace Prize.
Shortly after, the other prize-awarding organizations followed. The next thing the Nobel Foundation did was to try to agree on guidelines for how the Nobel Prize should be awarded. In 1900 the Nobel Foundation's newly created statutes were promulgated by King Oscar II. In 1905 the Union between Sweden and Norway was dissolved which meant the responsibility for awarding Nobel Prizes was split between the two countries. Norway's Nobel Committee became the awarder of the Peace Prize while Sweden became the awarder of the other prizes. In accordance with Nobel's will, the primary task of the Nobel Foundation is to manage the fortune Nobel left after him in a fund. Another important task of the Nobel Foundation is to represent the Nobel Prize to the outside world and to take charge of informal activities and issues related to the awarding of the Nobel Prizes; the Nobel Foundation is not involved in any way in the process of selecting the Nobel laureates. In many ways the Nobel Foundation is similar to an investment company in that it invests money in various ways to create a solid funding base for the prize and the administrative activities.
The Nobel Foundation is exempt from all taxes in Sweden and from investment taxes in the United States. Since the 1980s the Foundation's investments began to earn more money than previously. At the beginning of the 1980s the award money was 1 million SEK but in 2008 the award money had increased to 10 million SEK. According to the statutes the Foundation should consist of a Board with its seat in Stockholm, it should consist of five men. The Chairman of the board should be appointed by the King in Council; the other four members should be appointed by the trustees of the prize awarding institutions. The Board's first task was to choose an executive director from among the board members. A deputy director should be appointed by the King in Council and two deputies for the other members were appointed by the Trustees. However, since 1995 all the members of the board have been chosen by the Trustees and the Executive Director and the deputy Director appointed by the board itself. Apart from the board, the Nobel Foundation is made up by the prize-awarding institutions, the trustees of the prize-awarding institutions and auditors.
In 1965, the Foundation initiated the Nobel Symposia, a program that holds symposia "devoted to areas of science where breakthroughs around the world are occurring or deal with other topics of primary cultural or social significance." The symposia has covered topics such as prostaglandins, chemical kinetics, diabetes mellitus, string theory and the Cold War in the 1980s. The Nobel Symposium Committee consists of members from the Nobel Committees in Chemistry, Peace and Physiology or Medicine. In 2007, the Nobel Charitable Trust, founded by Michael Nobel, Gustaf Nobel, Peter Nobel, Philip Nobel, announced their plans to establish a new Nobel prize, the Michael Nobel Energy Award, that will award innovations in alternative energy technology, it will be the first new Nobel prize established by the Nobel family