Joseph Westley Newman

Joseph Westley Newman (July 2, 1936 – March 6, 2015) was an American inventor and author who developed an "energy machine" deemed by the US Patent and Trademark Office to be a perpetual motion machine. He described this device in a book, "The Energy Machine of Joseph Newman". Newman alleged that he had a mechanical explanation for Albert Einstein's unified field theory of physics. After applying for patents on the perpetual motion motor, he battled for over seven years against what he claimed was a government conspiracy to suppress his supposed discoveries, garnering national attention as a result.
Early life.
After Newman graduated from Baker High School in Mobile, Alabama, he joined the U.S. Air Force in 1955 to serve as an expediter, and was stationed at Ramey Air Force Base in Puerto Rico where he witnessed Hurricane Betsy devastate the island in 1956. The aftermath of the hurricane prompted Newman to make a pledge to God that he would devote the rest of his life to help humanity.
After leaving the Air Force a year early on the G.I. Bill, Newman attended the University of Alabama, enrolling in economics and accounting courses. He left college after acquiring interest in inventing and not long after, was awarded patents for the first plastic barbells. After selling his barbell business, he had the capital "to buy science books" and began to study energy, electrical engineering, physics and electromagnetics.
Career controversies.
Joseph Newman applied for a patent on his "energy machine" in 1979, which was rejected by the US Patent and Trademark Office as a perpetual motion machine. From 1979 to 1986 he filed lawsuits against the patent office to force the award of his patent.
The Federal District Court ordered the machine turned over to the National Bureau of Standards for testing, conceding that "It's very unusual for us to be testing something for a patent." Matthew Heyman, a bureau spokesman, said, "I'm not aware of us ever having been involved in a patent case before."
Newman persuaded seven members of Congress to sponsor private bills on his behalf that would order the Patent Office to grant him a patent.
The NBS concluded that Newman's machine did not reach or exceed 100% efficiency as Newman claimed, and declared the patent unrewardable.
Later life.
In 1987 he announced a run for the American Presidency, claiming that God had instructed him to run in order that the extinction of humanity by 1999 might be averted, and that Nostradamus had predicted his existence. In 1989 Newman claimed, while already married, to have married his secretary and her 8-year-old daughter, acting on orders from God. The daughter was removed from his home by the authorities.
Documentary.
Jon Fox directed a 2015 documentary film about Newman, entitled "Newman". It provides background on Newman's childhood, his struggles to obtain a patent, and interviews with Newman in 2014, shortly before his death.


Bruce Cork

Bruce Cork (1916 – October 7, 1994) was a physicist who discovered the antineutron in 1956 while working at the Lawrence Berkeley National Laboratory. He retired from Lawrence in 1986. He died October 7, 1994 at the age of 78 after a long illness.


Bruce McKellar

Professor Bruce Harold John McKellar (born 1941) is an Honorary Professorial Fellow at the Centre of Excellence for Particle Physics at the Terascale (CoEPP) in the School of Physics at The University of Melbourne. The International Union of Pure and Applied Physics (IUPAP) elected him as its President-Designate in 2012. In November 2014 McKellar became President of IUPAP, the first-ever Australian to take on this role.
McKellar is a theoretical particle physicist who is known for his work on particle physics and many other fields such as nuclear physics and cosmology. His other work has had applications in photography, atmospherics physics and geophysics, as well as implications for pure mathematics.
On Australia Day (26 January 2014), McKellar was appointed a Companion of the Order of Australia (AC) by Governor-General Quentin Bryce, for his service to science, particularly theoretical physics, as an academic, educator and researcher, through seminal contributions to scientific development organisations, and as an author and mentor. The AC was the Australia's highest civilian honour.
Early years and education.
McKellar grew up in Bedgerabong in NSW, attending Bedgerabong Primary School which was then a one teacher school. His father was the teacher. He then attended Forbes High School before moving to Sydney at 16 to study a Bachelor of Science at the University of Sydney, which he completed with First Class Honours and the University Medal for Physics.
He received his PhD in the University of Sydney in 1965, and a Doctor of Science from the University of Melbourne in 1976.
Academic career.
Immediately on completion of his PhD, McKellar was appointed as lecturer at the University of Sydney. In 1965, McKellar was invited by J. Robert Oppenheimer to become a member of the Institute for Advanced Study, Princeton, USA, which he undertook from 1966 to 1968. He then returned to University of Sydney. In 1972, at the age of 30, McKellar was appointed as the Professor of Theoretical Physics at Melbourne University. He retired from this role in 2007.
He has held visiting positions at the French Atomic Energy Commission, Saclay (France), the TRIUMF Laboratories (Canada), the University of Washington (Seattle United States), the Los Alamos Laboratory (United States), CERN (Switzerland), the Yukawa Institute (Japan), the National Taiwan University, the National University of Singapore, the Australian National University and Adelaide University.
At Princeton McKellar began his work on weak interactions, calculating the parity violation in expected in nuclei. He also started his work on three and many body nuclear forces. It was characteristic of this work that he was applying the current algebra techniques of particle physics to obtain results about nuclei. During his time at the University of Melbourne, McKellar and his collaborators published his definitive study on three nucleon forces, famously known as the "Tucson-Melbourne" force. His work on weak interactions led to calculation of the electric dipole moments expected for the nucleon and atoms in various models of these interactions. This work then evolved into studies of related effects in the B meson system.
McKellar and his students also did foundational work on the behaviour of neutrinos propagating through a dense background of neutrinos as one finds in the early universe. He is well known for the "He McKellar Wilkens" phase, a seminal quantum physics result predicted by He and McKellar, and Wilkens (independently) in 1993–94.
McKellar has made significant contribution to the development of the study of physics in Australia. He was elected a Fellow of the Australian Academy of Science in 1987, was its Vice President for Physical Sciences from 2000–2004 and its Foreign Secretary from 2004–2006. He was a founding member of the Australian Research Council, playing a key role in both its establishment and development.
McKellar actively facilitates physics research, policy development and international collaboration globally, especially in the Asia-Pacific Region. He served on the Board of Trustees of the sia Pacific Centre for Theoretical Physics and on the Council of the Association of Asia Pacific Physical Societies for many years. He chaired the Regional Committee for Asia and the Pacific of the International Council for Science (ICSU) (2009–2011), as well as the Australia and New Zealand Association for the Advancement of Science (ANZAAS) (1992–1998).
McKellar is a Fellow of the Australian Institute of Physics, the Institute of Physics (UK), the American Physical Society, and the Australian Academy of Science.
Personal life.
Bruce McKellar married Loris Huckel in 1963. They have 2 children and 4 grandchildren and live in Melbourne, Australia.


Robert Street

Robert Street AO FAA (16 December 1920 – 4 July 2013) was a British academic and academic administrator.
Born in Wakefield, Yorkshire and educated at Hanley High School, he was offered a scholarship to New College, Oxford in 1939, but upon failing to meet the university's Latin requirement he instead took up a place at King's College London where he studied physics. He later completed his PhD at University College, Nottingham. He worked as a senior lecturer at the University of Sheffield from 1954 to 1960 and as Foundation Professor of Physics at Monash University from 1960 to 1974. He later served as vice-chancellor of the University of Western Australia from 1978 to 1986. He also served as president of the Australian Institute of Physics.
Street was appointed an Officer of the Order of Australia in 1985 "For Service to Learning", was elected a Fellow of the Australian Academy of Science in 1973 and was awarded the Centenary Medal in 2001 "For service to Australian society and science in physics".


Bulletin of the Lebedev Physics Institute

Bulletin of the Lebedev Physics Institute (Russian: "Краткие сообщения по физике", "Kratkue Soobsheniya po fisike") is a peer-reviewed scientific journal of physics. The journal was established in 1970, and is published by the Lebedev Physical Institute (in Russian) a monthly basis. Springer publishes an English translation of the journal. It is edited by Oleg N. Krokhin. The online version is available since 2007.
The "Bulletin" covers research results from Prokhorov General Physics Institute and the Institute for Nuclear Research of the Russian Academy of Sciences in addition to those of the Lebedev Physical Institute.
Indexing.
"Bulletin of the Lebedev Physics Institute" is abstracted and indexed in the following databases:


Carlo Franzinetti

Carlo Franzinetti (March 31, 1923 in Rome – November 28, 1980 in Llantwit Major) was an Italian experimental physicist.
Personal biography.
Carlo Franzinetti was born in Rome, son of Guido Franzinetti, a music critic, and Ada Guastalla, a mathematician and linguist. He was married to Prof. Joan Rees.
During the German occupation of Italy, he was an active member in Resistance Movement. He was one of the leaders of a student group of anti-fascist activists that included Carlo Lizzani, , , and other important figures in the development of post-war Italy.
He graduated from the University of Rome "La Sapienza" in Physics with a thesis about projects of construction of an isotope separator based on thermophoresis.
His professional scientific career started when he was 25 (8 May 1948), when he published the article "Emission of Li8 in the Explosive Disintegration of Nuclei" with R.M. Payne in the science journal "Nature".
Cosmic radiation research.
In 1947 he joined the University of Bristol as a Research Assistant at the H.H. Wills Physical Laboratory, under the guidance of Nobel Laureate Prof. C. F. Powell. Powell's team's research looked at the sub-nuclear structure of matter through the study of cosmic rays with nuclear emulsion.
In 1950 he returned to Rome but he continued his study of cosmic rays. One of the ideas that came out of Powell's team was an expedition in the Mediterranean region to study cosmic radiation at high atmosphere (25 to 30 km) using aerostatic balloons carrying photographic emulsion. Carlo followed the expedition, which took place during the summers of 1952 and 1953 in Naples and in Cagliari, with researchers and students from 13 different physics institutes from various countries. Thirteen balloons were launched, 3 of which were test balloons. Of the other ten, 7 were recovered and 40% of the emulsions had been exposed to cosmic radiation.
Study of neutrinos.
In 1962 he began working in Geneva as a Senior Physicist at the European Organization for Nuclear Research (CERN). During his time there he played a key role in promoting and working with the Heavy Liquid Bubble Chamber, Gargamelle, where he also conducted his studies of neutrinos. The first report for the request of a common European Heavy Liquid Chamber at CERN was submitted by but, needing the support of Italian and possibly British physicists, he contacted Franzinetti. Franzinetti led the Italian group concerned with the proposal and construction of the Heavy Liquid Chamber, Gargamelle. At CERN he studied, at different energies, with neutrino and antineutrino beams, on different kinds of targets, the production of pions and strange particles, elastic and quasi-elastic interactions, and, through analysis of the interactions of Neutrinos, he studied the form factors of nucleons.
Biophysics.
His interest in biophysics started during his time in Pisa. During his time in Turin he led a biophysics team of students from the Universities of Turin and Pisa, which conducted studies on visual perception. He followed students alongside , a physiologist at the University of Pisa.


Joseph Petavel

Sir Joseph Ernest Petavel KBE FRS D.Sc. (14 August 1873 – 31 March 1936) was a British physicist.
He was born in London and educated at Lausanne, Geneva, before he joined University College, London, in 1893, where he studied mechanical and electrical engineering. He was elected a Fellow of the Royal Society in 1907.
He was the second director of the NPL in Bushy Park from 1919 to 1936, living in Bushy House. During his time there he devised the Petavel gauge for the measurement of the pressures within exploding gases.
He was invested Knight Commander of the Order of the British Empire (KBE) in the 1920 civilian war honours for his wartime work as Chairman of Aerodynamics Sub-Committee of the Advisory Committee on Aeronautics.
He died at Bushy House and was buried in the west side of Highgate Cemetery.


Physical Review Physics Education Research


Electronic anticoincidence

Electronic anticoincidence is a method (and its associated hardware) widely used to suppress unwanted, "background" events in high energy physics, experimental particle physics, gamma-ray spectroscopy, gamma-ray astronomy, experimental nuclear physics, and related fields. In the typical case, a high-energy interaction, or event, that it is desired to study occurs and is detected by some kind of electronic detector, creating a fast electronic pulse in the associated nuclear electronics. But the desired events are mixed up with a significant number of other events, produced by other particles or other processes, which create indistinguishable events in the detector. Very often it is possible to arrange other physical photon or particle detectors to intercept the unwanted background events, producing essentially simultaneous pulses that can be used with fast electronics to reject, or veto, the unwanted background.
Gamma-ray astronomy.
Early experimenters in X-ray and gamma-ray astronomy found that their detectors, flown on balloons or sounding rockets, were corrupted by the large fluxes of high-energy photon and cosmic-ray charged-particle events. Gamma-rays, in particular, could be collimated by surrounding the detectors with heavy shielding materials made of lead or other such elements, but it was quickly discovered that the high fluxes of very penetrating high-energy radiation present in the near-space environment created showers of secondary particles that could not be stopped by reasonable shielding masses. To solve this problem, detectors operating above 10 or 100 keV were often surrounded by an active anticoincidence shield made of some other detector, which could be used to reject the unwanted background events.
 An early example of such a system, first proposed by Kenneth John Frost in 1962, is shown in the figure. It has an active CsI(Tl) scintillation shield around the X-ray/gamma-ray detector, also of CsI(Tl), with the two connected in electronic anticoincidence to reject unwanted charged particle events and to provide the required angular collimation.
Plastic scintillators are often used to reject charged particles, while thicker CsI, bismuth germanate ("BGO"), or other active shielding materials are used to detect and veto gamma-ray events of non-cosmic origin. A typical configuration might have a NaI scintillator almost completely surrounded by a thick CsI anticoincidence shield, with a hole or holes to allow the desired gamma rays to enter from the cosmic source under study. A plastic scintillator may be used across the front which is reasonably transparent to gamma rays, but efficiently rejects the high fluxes of cosmic-ray protons present in space.
Compton suppression.
In gamma-ray spectroscopy, Compton suppression is a technique that improves the signal by preventing data which has been corrupted by the incident gamma ray getting Compton scattered out of the target before depositing all of its energy. The effect is to minimize the Compton edge feature in the data.
The high resolution solid state germanium detectors used in gamma ray spectroscopy are very small, typically only a few centimeters in diameter and with thickness ranging from a few centimeters to a few millimeters. Since the detectors are so small, it is likely that the gamma ray will Compton scatter out of the detector before it deposits all of its energy. In this case, the energy reading by the data acquisition system will come up short: the detector records an energy which is only a fraction of the energy of the incident gamma ray.
In order to counteract this, the expensive and small high resolution detector is surrounded by larger and cheaper low resolution detectors, usually sodium iodide scintillators. The main detector and the suppression detector are run in anti-coincidence, which means that if they both detect a gamma ray then the gamma ray has scattered out of the main detector before depositing all of its energy and the data is ignored. The much larger suppression detector has much more stopping power than the main detector, and it is highly unlikely that the gamma ray will scatter so that it escapes both devices.
Nuclear and particle physics.
Modern experiments in nuclear and high-energy particle physics almost invariably use fast anticoincidence circuits to veto unwanted events. The desired events are typically accompanied by unwanted background processes that must be suppressed by enormous factors, ranging from thousands to many billions, to permit the desired signals to be detected and studied. Extreme examples of these kinds of experiments may be found at the Large Hadron Collider, where the enormous Atlas and CMS detectors must reject huge numbers of background events at very high rates, to isolate the very rare events being sought.
See also.
Nuclear electronics
HEAO 1
HEAO 3
INTEGRAL
Uhuru (satellite)
Gamma-ray spectroscopy


Mikhail Anisimov

Mikhail Alexeevich Anisimov (Russian: Михаил Алексе́евич Анисимов, born November 2, 1941, Baku, Azerbaijan, USSR) is a Russian and American interdisciplinary scientist.
Early life.
Anisimov received a degree in petroleum engineering from Grozny Petroleum Institute in 1964, a doctorate in physical chemistry from Moscow State University in 1969, and a doctor of science degree in molecular and thermal physics from the Kurchatov Institute of Atomic Energy in Moscow in 1976.
Career.
From 1969 through 1977, Anisimov worked at the U.S.S.R. State Committee for Standards and Product Quality Management (Russian: Госстандарт), where his postdoctoral mentor was Alexander V. Voronel. From 1978 until 1993, Anisimov was a professor and the chairman of the Physics Department of Gubkin Russian State University of Oil and Gas. In 1994, Anisimov began working in the United States as a professor for both the Department of Chemical and Biomolecular Engineering and for the Institute of Physical Science and Technology at the University of Maryland, College Park.
Research.
Anisimov’s field of research is thermodynamics of fluids and fluid mixtures, liquid crystals, polymers, and other soft-matter materials. His research group at the University of Maryland (jointly with Jan V. Sengers ) is one of the leading international authorities in the field of critical phenomena and phase transitions. Anisimov works in theory and experiments, fundamental problems and applications. He has been an author and a co-author of 2 books, 14 book chapters and review articles and more than 400 published journal and encyclopedia articles, conference proceedings and reports.
Personal life.
Anisimov has four children. His eldest daughter, Tanya Anisimova, is a cellist and composer.


Stan Bentvelsen

Stanislaus Cornelius Maria (Stan) Bentvelsen (Schipluiden, 6 May 1965) is a Dutch physicist. He is the director of Nikhef since 2014.
Bentvelsen studied Physics at the Universiteit van Amsterdam (UvA). In 1994 he completed his thesis at the UvA in 1994
From 1994 to 2000 he was a researcher at the CERN in Geneva.
From 2000 to 2005 Bentvelsen worked at the Nikhef (the Dutch National Institute for Subatomic Physics that performs research in particle physics and astroparticle physics). Since 2005 he teaches at the Universiteit van Amsterdam.
Since 2014 he is the director of the Nikhef. He succeeded professor Frank Linde on December 1, 2014.


Nicole Oresme

Nicole Oresme (; c. 1320–1325 – July 11, 1382), also known as Nicolas Oresme, Nicholas Oresme, or Nicolas d'Oresme, was a significant philosopher of the later Middle Ages. He wrote influential works on economics, mathematics, physics, astrology and astronomy, philosophy, and theology; was Bishop of Lisieux, a translator, a counselor of King Charles V of France, and one of the most original thinkers of 14th-century Europe.
Life.
Nicole Oresme was born c. 1320–1325 in the village of Allemagnes (today's Fleury-sur-Orne) in the vicinity of Caen, Normandy, in the diocese of Bayeux. Practically nothing is known concerning his family. The fact that Oresme attended the royally sponsored and subsidised College of Navarre, an institution for students too poor to pay their expenses while studying at the University of Paris, makes it probable that he came from a peasant family.
Oresme studied the "arts" in Paris, together with Jean Buridan (the so-called founder of the French school of natural philosophy), Albert of Saxony and perhaps Marsilius of Inghen, and there received the Magister Artium. He was already a regent master in arts by 1342, during the crisis over William of Ockham's natural philosophy.
In 1348, he was a student of theology in Paris. In 1356, he received his doctorate and in the same year he became grand master ("grand-maître") of the College of Navarre. In 1364, he was appointed dean of the Cathedral of Rouen. Around 1369, he began a series of translations of Aristotelian works at the request of Charles V, who granted him a pension in 1371 and, with royal support, was appointed bishop of Lisieux in 1377. In 1382, he died in Lisieux.
Scientific work.
Cosmology.
In his "Livre du ciel et du monde" Oresme discussed a range of evidence for and against the daily rotation of the Earth on its axis. From astronomical considerations, he maintained that if the Earth were moving and not the celestial spheres, all the movements that we see in the heavens that are computed by the astronomers would appear exactly the same as if the spheres were rotating around the Earth. He rejected the physical argument that if the Earth were moving the air would be left behind causing a great wind from east to west. In his view the Earth, Water, and Air would all share the same motion. As to the scriptural passage that speaks of the motion of the Sun, he concludes that "this passage conforms to the customary usage of popular speech" and is not to be taken literally. He also noted that it would be more economical for the small Earth to rotate on its axis than the immense sphere of the stars. Nonetheless, he concluded that none of these arguments were conclusive and "everyone maintains, and I think myself, that the heavens do move and not the Earth."
Critiques of astrology.
In his mathematical work, Oresme developed the notion of incommensurate fractions, fractions that could not be expressed as powers of one another, and made probabilistic, statistical arguments as to their relative frequency. From this, he argued that it was very probable that the length of the day and the year were incommensurate (irrational), as indeed were the periods of the motions of the moon and the planets. From this, he noted that planetary conjunctions and oppositions would never recur in quite exactly the same way. Oresme maintained that this disproves the claims of astrologers who, thinking "they know with punctual exactness the motions, aspects, conjunctions and oppositions… [judge] rashly and erroneously about future events."
Oresme's critique of astrology in his "Livre de divinacions" treats it as having six parts. The first, essentially astronomy, the movements of heavenly bodies, he considers good science but not precisely knowable.
The second part deals with the influences of the heavenly bodies on earthly events at all scales. Oresme does not deny such influence, but states, in line with a commonly held opinion, that it could either be that arrangements of heavenly bodies signify events, purely symbolically, or that they actually cause such events, deterministically. Mediaevalist Chauncey Wood remarks that this major elision "makes it very difficult to determine who believed what about astrology".
The third part concerns predictiveness, covering events at three different scales: great events such as plagues, famines, floods and wars; weather, winds and storms; and medicine, with influences on the humours, the four Aristotelian fluids of the body. Oresme criticizes all of these as misdirected, though he accepts that prediction is a legitimate area of study, and argues that the effect on the weather is less well known than the effect on great events. He observes that sailors and farmers are better at predicting weather than astrologers, and specifically attacks the astrological basis of prediction, noting correctly that the zodiac has moved relative to the fixed stars (because of precession of the equinoxes) since the zodiac was first described in ancient times.
These first three parts are what Oresme considers the physical influences of the stars and planets (including sun and moon) on the earth, and while he offers critiques of them, he accepts that effects exist. The last three parts are what Oresme considers to concern (good or bad) fortune. They are interrogations, meaning asking the stars when to do things such as business deals; elections, meaning choosing the best time to do things such as getting married or fighting a war; and nativities, meaning the natal astrology with birth charts that forms much of modern astrological practice. Oresme classifies interrogations and elections as "totally false" arts, but his critique of nativities is more measured. He denies that any path is predetermined by the heavenly bodies, because humans have free will, but he accepts that the heavenly bodies can influence behaviour and habitual mood, via the combination of humours in each person. Overall, Oresme's skepticism is strongly shaped by his understanding of the scope of astrology. He accepts things a modern skeptic would reject, and rejects some things — such as the knowability of planetary movements, and effects on weather — that are accepted by modern science.
Sense perception.
In discussing the propagation of light and sound, Oresme adopted the common medieval doctrine of the multiplication of species, as it had been developed by optical writers such as Alhacen, Robert Grosseteste, Roger Bacon, John Pecham, and Witelo. Oresme maintained that these species were immaterial, but corporeal (i.e., three-dimensional) entities.
Mathematics.
Oresme's most important contributions to mathematics are contained in "Tractatus de configurationibus qualitatum et motuum". In a quality, or accidental form, such as heat, he distinguished the "intensio" (the degree of heat at each point) and the "extensio" (as the length of the heated rod). These two terms were often replaced by "latitudo" and "longitudo". For the sake of clarity, Oresme conceived the idea of visualizing these concepts by plane figures, approaching what we would now call rectangular coordinates. The intensity of the quality was represented by a length or "latitudo" proportional to the intensity erected perpendicular to the base at a given point on the base line, which represents the "longitudo". Oresme proposed that the geometrical form of such a figure could be regarded as corresponding to a characteristic of the quality itself. Oresme defined a uniform quality as that which is represented by a line parallel to the longitude, and any other quality as difform. Uniformly varying qualities are represented by a straight line inclined to the axis of the longitude, while he described many cases of nonuniformly varying qualities. Oresme extended this doctrine to figures of three dimensions. He considered this analysis applicable to many different qualities such as hotness, whiteness, and sweetness. Significantly for later developments, Oresme applied this concept to the analysis of local motion where the "latitudo" or intensity represented the speed, the "longitudo" represented the time, and the area of the figure represented the distance travelled.
He shows that his method of figuring the latitude of forms is applicable to the movement of a point, on condition that the time is taken as longitude and the speed as latitude; quantity is, then, the space covered in a given time. In virtue of this transposition, the theorem of the "latitudo uniformiter difformis" became the law of the space traversed in case of uniformly varied motion; thus Oresme published what was taught over two centuries prior to Galileo's making it famous. Diagrams of the velocity of an accelerating object against time in "On the Latitude of Forms" by Oresme have been cited to credit Oresme with the discovery of "proto bar charts".
In "De configurationibus" Oresme introduces the concept of curvature as a measure of departure from straightness, for circles he has the curvature as being inversely proportional to radius and attempts to extend this to other curves as a continuously varying magnitude.
Significantly, Oresme developed the first proof of the divergence of the harmonic series. His proof, requiring less advanced mathematics than current "standard" tests for divergence (for example, the integral test), begins by noting that for any "n" that is a power of 2, there are "n"/2 − 1 terms in the series between 1/("n"/2) and 1/"n". Each of these terms is at least 1/"n", and since there are "n"/2 of them they sum to at least 1/2. For instance, there is one term 1/2, then two terms 1/3 + 1/4 that together sum to at least 1/2, then four terms 1/5 + 1/6 + 1/7 + 1/8 that also sum to at least 1/2, and so on. Thus the series must be greater than the series 1 + 1/2 + 1/2 + 1/2 + ..., which does not have a finite limit. This proves that the harmonic series must be divergent. This argument shows that the sum of the first "n" terms grows at least as fast as formula_1. (See also Harmonic series)
Oresme was the first mathematician to prove this fact, and (after his proof was lost) it was not proven again until the 17th century by Pietro Mengoli.
He also worked on fractional powers, and the notion of probability over infinite sequences, ideas which would not be further developed for the next three and five centuries, respectively.
On local motion.
Oresme, like many of his contemporaries such as John Buridan and Albert of Saxony, shaped and critiqued Aristotle's and Averroes's theories of motion to their own liking. Taking inspiration from the theories of "forma fluens" and "fluxus formae", Oresme would suggest his own descriptions for change and motion in his commentary of "Physics". "Forma fluens" is described by William of Ockham as "Every thing that is moved is moved by a mover," and "fluxus formae" as "Every motion is produced by a mover." Buridan and Albert of Saxony each subscribed to the classic interpretation of flux being an innate part of an object, but Oresme differs from his contemporaries in this aspect. Oresme agrees with "fluxus formae" in that motion is attributed to an object, but that an object is “set into” motion, rather than “given” motion, denying a distinction between a motionless object and an object in motion. To Oresme, an object moves, but it is not a moving object. Once an object begins movement through the three dimensions it has a new “modus rei” or “way of being,” which should only be described through the perspective of the moving object, rather than a distinct point. This line of thought coincides with Oresme's challenge to the structure of the universe. Oresme's description of motion was not popular, although it was thorough. A Richard Brinkley is thought to be an inspiration for the modus-rei description, but this is uncertain.
Political thought.
Oresme provided the first modern vernacular translations of Aristotle's moral works that are still extant today. Between 1371 and 1377 he translated Aristotle's "Ethics", "Politics" and "Economics" (the last of which is nowadays considered to be pseudo-Aristotelian) into Middle French. He also extensively commented on these texts, thereby expressing some of his political views. Like his predecessors Albert the Great, Thomas Aquinas and Peter of Auvergne (and quite unlike Aristotle), Oresme favours monarchy as the best form of government. His criterium for good government is the common good. A king (by definition good) takes care of the common good, whereas a tyrant works for his own profit. A monarch can ensure the stability and durability of his reign by letting the people participate in government. This has rather confusingly and anachronistically been called popular sovereignty. Like Albert the Great, Thomas Aquinas, Peter of Auvergne and especially Marsilius of Padua, whom he occasionally quotes, Oresme conceives of this popular participation as rather restrictive: only the multitude of reasonable, wise and virtuous men should be allowed political participation by electing and correcting the prince, changing the law and passing judgement. Oresme, however, categorically denies the right of rebellion since it endangers the common good. Unlike earlier commentators, however, Oresme prescribes the law as superior to the king's will. It must only be changed in cases of extreme necessity. Oresme favours moderate kingship, thereby negating contemporary absolutist thought, usually promoted by adherents of Roman law. Furthermore, Oresme doesn't comply to contemporary conceptions of the French king as sacred, as promoted by in his "" or in his "Traité du sacre". Although he heavily criticises the Church as corrupt, tyrannical and oligarchical, he never fundamentally questions its necessity for the spiritual well-being of the faithful.
It has traditionally been thought that Oresme's Aristotelian translations had a major influence on King Charles V's politics: Charles' laws concerning the line of succession and the possibility of a regency for an underage king have been accredited to Oresme, as has the election of several high-ranking officials by the king's council in the early 1370s. Oresme may have conveyed Marsilian and conciliarist thought to Jean Gerson and Christine de Pizan.
Economics.
With his "Treatise on the origin, nature, law, and alterations of money" ("De origine, natura, jure et mutationibus monetarum"), one of the earliest manuscripts devoted to an economic matter, Oresme brings an interesting insight on the medieval conception of money. Oresme's viewpoints of theoretical architecture are outlined in Part 3 and 4 of his work from "De moneta," which he completed between 1356 and 1360. His belief is that humans have a natural right to own property; this property belongs to the individual and community. In Part 4, Oresme provides a solution to a political problem as to how a monarch can be held accountable to put the common good before any private affairs. Though the monarchy rightfully has claims on all money given an emergency, Oresme states that any ruler that goes through this is a “Tyrant dominating slaves”. Oresme was one of the first medieval theorists that did not accept the right of the monarch to have claims on all money as well as “his subjects’ right to own private property.”
Psychology.
Oresme was known to be a well rounded psychologist. He practiced the technique of “inner senses” and studied the perception of the world. Oresme contributed to 19th and 20th century psychology in the fields of cognitive psychology, perception psychology, psychology of consciousness, and psychophysics. Oresme discovered the psychology of unconscious and came up with the theory of unconscious conclusion of perception. He developed many ideas beyond quality, quantity, categories and terms which were labeled “theory of cognition”.


ANU Research School of Physics and Engineering

The Research School of Physics (RSPhys) was established with the creation of the Australian National University (ANU) in 1947. Located at the ANU's main campus in Canberra, the school is one of the four founding research schools in the ANU's Institute of Advanced Studies.
As part of the Institute of Advanced Studies it is primarily a research school with limited interaction with the ANU's undergraduate students. With a total of around 200 employees the school has approximately 60 PhD students and 70 academic staff. The school is divided into separate research departments although PhD students can often be based in more than one department.
Research.
RSPhys is one of the leading physics research institutions in Australia. Major research facilities at the school include the 14UD NEC Pelletron accelerator and associated modular superconducting linac run by the Department of Nuclear Physics, the H-1NF flexible Stellarator Heliac run by the Plasma Research Laboratory plus an extensive range of smaller experimental and computational equipment.
Research ranges from the fundamental to the applied, including both experimental and theoretical work. The school's primary research areas are: materials science and engineering; lasers, nonlinear optics and photonics; nanotechnology and mesoscopic physics; physics of atoms, molecules and the nucleus; plasma physics and surface science; physics and the environment.
The nuclear physics 14UD is one of a handful of large Van de Graaff accelerators in the world. It was the largest machine of its type when installed in 1974. After many upgrades the 14UD is capable of running terminal voltage of up 16.7 MV. Charging is via three inductive charging chains. In 1996 a superconducting RF linac was installed that is used as an energy booster for the 14UD enabling higher energies to be reached.
History.
Sir Mark Oliphant was the founder of the School and its first Director from 1950 to 1963. The school was originally called the "Research School of Physical Sciences" with "Engineering" being added to its title in 1990 to highlight the large amount of engineering work that is undertaken in the school. The name was again changed in 2008 to the "Research School of Physics and Engineering" to coincide with the merger with ANU's undergraduate physics teaching department. In support of a university strategic focus on the discipline of Engineering at ANU, the School name was changed to “Research School of Physics” in August 2019.  Nonetheless, the Research School of Physics retains a strength in graduate research in the fields of electronic materials, optics and instrumentation engineering. The long history of engineering physics remains an attraction for students and staff who work between the disciplines of physics and engineering.
For much of the early years the focus of a large part of the school was designing, re-designing and building a cyclo-synchrotron that in its final intended form was to produce a beam of 10.6 GeV protons for nuclear physics research. Designed to be a world class research machine it was referred to within the school as "The Big Machine". Due to shifting goalposts and huge costs the cyclo-synchrotron was never completed. The small 7.7 MeV cyclotron designed to function as the proton injector was completed in 1955, and the large homopolar generator intended to power the system was first operated in 1962, but by this time work on "The Big Machine" itself had been abandoned.
The homopolar generator, the largest ever built, was capable of supplying currents of over 2 megaamperes. Even though it was never used for its intended purpose it ended up being used for numerous research projects requiring an extremely high current source until its disassembly in 1986. One of these projects was the invention and development of the railgun by John Barber and Richard Marshall. The school also benefited in an indirect way from the construction of the massive generator, the accumulated engineering experience and techniques where later used to build other research equipment around the school including the Plasma Physics H1NF Heliac. Some parts of the homopolar generator are now on permanent display on the lawn outside the research school.
The school has been home to many different particle accelerators over the years. The first accelerator installed was a 1.25 MV Cockcroft-Walton known as HT1, this was in use from 1952 until 1967 when it was sold to the University of New South Wales. A second smaller 600 kV Cockcroft-Walton machine (HT2) was assembled in house using many spare parts acquired for HT1. In 1955 the UK government supplied a 33 MeV electron synchrotron as a gift. It was moved to the University of Western Australia in 1961. During 1960–1980 a HVEC EN tandem accelerator was used by nuclear physics for light ion research. 1975 saw the school's 14UD accelerator come online, which has since been augmented with a superconducting linear accelerator.
On 5 July 1960 a fire during the night destroyed much of the eastern end of the Cockcroft Building. The damage included the drawing office, many student's and staff's results and files and the control room for the 600 kV Cockcroft-Walton accelerator. The 600 kV accelerator though only water damaged had to be scrapped. Refurbishment of the burnt out area was completed in September 1961.
Early departments that have now been spun off into research schools of their own include the departments of "Astronomy" and "Geophysics and Geochemistry". Geophysics and Geochemistry separated into the Research School of Earth Sciences in 1973. Mount Stromlo Observatory became part of the Department of Astronomy in 1957. While part of the school, the Department of Astronomy developed Siding Spring Observatory and installed many new telescopes at Mount Stromlo Observatory. It separated into the Research School of Astronomy and Astrophysics in 1986.


Wilson Sibbett

Wilson Sibbett CBE FRS FRSE (born 1948) is a British physicist noted for his work on ultrashort pulse lasers and Streak cameras. He is the Wardlaw Professor of Physics at St Andrews University.
Life.
He was born in Portglenone in County Antrim, Northern Ireland, in March 1948.
He studied Physics at Queen's University, Belfast, and graduated BSc in 1970, then studying at postgraduate level, gaining a PhD in Laser Physics in 1973. He began lecturing at Imperial College London in 1973, rising to Reader before moving to St Andrews University as full Professor in 1985. From 1988 he was Head of Physics and Astronomy at the University.
He worked with Miles Padgett and Alan James Duncan to create optical instruments to measure the Orbital angular momentum of light.
He was made a Fellow of the Royal Society in 1997, and awarded the Rumford Medal in 2000. The Society elected him their first Chief Advisor on Science.
He was appointed a Commander of the Order of the British Empire (CBE) in 2001.
In 1989 he was made a Fellow of The Royal Society of Edinburgh. He was Vice-President for Physical Sciences from 2010 - 2013.


Nuclear Physics Laboratory


Applied Radiation and Isotopes

Applied Radiation and Isotopes is a peer-reviewed scientific journal published by Elsevier. It was established in 1993 and its scope covers applications of ionizing radiation and radionuclides.
The current editors-in-chief are Richard P. Hugtenburg (Swansea University) and Brian E. Zimmerman (National Institute of Standards and Technology).
Abstracting and indexing.
"Applied Radiation and Isotopes" is indexed in:
It has a 2017 impact factor of 1.123, according to the "Journal Citation Reports".
Former titles history.
The history of the journal is as follows:


Feinberg reinterpretation principle


Christian Spielmann

Christian Spielmann (born 1963, Innsbruck, Austria) is an Austrian physicist and a professor at the University of Jena
Education and career.
Spielmann obtained his Ph.D. in 1989 at the Vienna University of Technology where he also habilitated in 1999. In 2002 he became professor of experimental physics at the University of Würzburg, before moving to Jena in 2008. In 1998, Spielman received the Fritz-Kohlrausch-Physik Award (for achievements in experimental physics by junior scientists) from the Austrian Physical Society and in 2011 the Thuringian Research Award for his work in X-ray spectroscopy.


Natalia M. Litchinitser

Natalia M. Litchinitser is an Electrical Engineer and Professor at Duke University. She works on optical metamaterials and their application in photonic devices. Litchinitser is a Fellow of the American Physical Society, The Optical Society and the Institute of Electrical and Electronics Engineers.
Early life and education.
Litchinitser was born in Russia. She earned her undergraduate degree in physics at the Moscow State University. She moved to the United States for her graduate studies and she joined the Illinois Institute of Technology. Her doctoral research considered Fiber Bragg grating filters for the compensation of dispersion. In 1997 Litchinitser joined the Institute of Optics in Rochester, New York, where she was made a postdoctoral research fellow. She joined Bell Labs at the same time that the field of metamaterials was emerging, and switched her focus on the theoretical properties of metamaterials that manipulate the visible portion of the electromagnetic spectrum. In 2005 Litchinitser moved to the University of Michigan.
Research and career.
In 2008 Litchinitser was made an Assistant Professor of Optics at the State University of New York, and was promoted to Associate Professor in 2011. She moved to Duke University in 2018. Her research focusses on metamaterials and topological photonics. Metamaterials are artificial structures that manipulate waves using a carefully controlled nanostructure as opposed to chemistry. She has used metamaterials to create a hyperlens; that is, a lens that escapes the diffraction limit by converting evanescent waves into propagating waves. To create the lens Litchinitser made use of gold and poly(methyl methacrylate) arranged in Slinky-like formation, which can overcome the diffraction limit to visible light. It is hoped that such lens could be used to improve the resolution of endscopes, allowing early detection of certain cancers.
Litchinitser makes use of metamaterials to manipulate electric and magnetic fields, engineering shaped beams of light. These shaped beams (rather than the typical 'circular' beam, a beam that is shaped more like a vortex) of light allow access to otherwise forbidden higher-order spectroscopic transitions. Metamaterials offer the potential to tailor the orbital angular momentum and polarisation states of light. Circularly polarised light involves an electric field that rotates around the direction of propagation, such that the photons carry spin angular momentum. When spin-orbit interactions are controlled, spin angular momentum can be converted into orbital angular momentum. Orbital angular momentum (or vortex beams) can make symmetry-forbidden transitions possible, with a transition rate that increases when the size of the beam decreases. She has since shown that it is possible to measure a vortex laser's orbital angular momentum modes using a tunable micro-transceiver chip-based detector, offering hope that such systems could be used for fast data transmission. The detector makes use of a photodetector that is responsive to orbital angular momentum modes.
Topological photonics looks to navigate light around tight corners using tiny waveguides that eliminate the scattering of light. To achieve this, Litchinitser designed crystal lattices with carefully controlled geometries, which allow light to travel perfectly across their surfaces but block it from travelling through the interior. The ability for light to travel around corners is essential for photonic-based microchips, which will be essential for future data transmission.
Litchinitser delivered a plenary lecture at the 2018 SPIE Optics and Photonics conference, where she discussed the interaction of structured light and nanostructured media. At the 2020 SPIE Optics and Photonics conference Litchinitser chaired the session on Nanoscience and Engineering.


GRADE (CERN research programme)

GRADE (Generic pre-R&D at IdeaSquare) is a CERN research programme. The programme was approved by the CERN Research Board in December 2015.


Franz Mandl (physicist)

Franz Mandl (1923–2009) was a British theoretical physicist, known for his graduate-level textbooks.
Early life and education.
Mandl was born in Vienna in 1923 into a Jewish family. They moved to Berlin in the 1920s, and after the rise of Nazi Germany, the family emigrated to England as refugees in 1936. Mandl received a scholarship to study at Lincoln College, Oxford where he received his undergraduate and doctorate degrees in physics.
Academic career.
After receiving his doctorate, Mandl spent a few years in the US, before returning to the UK to become a reader of physics at the University of Manchester. He spent his career there collaborating in atomic research and writing textbooks. His books were considered influential to the graduate study of theoretical physics.
Personal life and death.
Mandl married Betty Clifford, a mathematician whom he met while studying at Oxford.
He died in 2009 at the age of 85.


Test theories of special relativity

Test theories of special relativity give a mathematical framework for analyzing results of experiments to verify special relativity.
An experiment to test the theory of relativity cannot assume the theory is true, and therefore needs some other framework of assumptions that are wider than those of relativity. For example, a test theory may have a different postulate about light concerning one-way speed of light vs. two-way speed of light, it may have a preferred frame of reference, and may violate Lorentz invariance in many different ways. Test theories predicting different experimental results from Einstein's special relativity, are "Robertson's test theory (1949)", and the "Mansouri–Sexl theory (1977)" which is equivalent to Robertson's theory.
Another, more extensive model is the Standard-Model Extension, which also includes the standard model and general relativity.
Robertson–Mansouri–Sexl framework.
Basic principles.
Howard Percy Robertson (1949)
extended the Lorentz transformation by adding additional parameters.
He assumed a preferred frame of reference, in which the two-way speed of light, "i.e." the average speed from source to observer and back, is isotropic, while it is anisotropic in relatively moving frames due to the parameters employed. In addition, Robertson used the Poincaré–Einstein synchronization in all frames, making the one-way speed of light isotropic in all of them.
A similar model was introduced by Reza Mansouri and Roman Ulrich Sexl (1977). Contrary to Robertson, Mansouri–Sexl not only added additional parameters to the Lorentz transformation, but also discussed different synchronization schemes. The Poincaré–Einstein synchronization is only used in the preferred frame, while in relatively moving frames they used "external synchronization", "i.e.", the clock indications of the preferred frame are employed in those frames. Therefore, not only the two-way speed of light but also the one-way speed is anisotropic in moving frames.
Since the two-way speed of light in moving frames is anisotropic in both models, and only this speed is measurable without synchronization scheme in experimental tests, the models are experimentally equivalent and summarized as the "Robertson–Mansouri–Sexl test theory" (RMS). On the other hand, in special relativity the two-way speed of light is isotropic, therefore RMS gives different experimental predictions as special relativity. By evaluating the RMS parameters, this theory serves as a framework for assessing possible violations of Lorentz invariance.
Theory.
In the following, the notation of Mansouri–Sexl is used. They chose the coefficients "a", "b", "d", "e" of the following transformation between reference frames:
where "T", "X", "Y", "Z" are the Cartesian coordinates measured in a postulated preferred frame (in which the speed of light "c" is isotropic), and "t", "x", "y", "z" are the coordinates measured in a frame moving in the +"X" direction (with the same origin and parallel axes) at speed "v" relative to the preferred frame. And therefore formula_5 is the factor by which the interval between ticks of a clock increases when it moves (time dilation) and formula_6 is factor by which the length of a measuring rod is shortened when it moves (length contraction). If formula_7 and formula_8 and formula_9 then the Lorentz transformation follows. The purpose of the test theory is to allow "a"("v") and "b"("v") to be measured by experiment, and to see how close the experimental values come to the values predicted by special relativity. (Notice that Newtonian physics, which has been conclusively excluded by experiment, results from formula_10)
The value of "e"("v") depends only on the choice of clock synchronization and cannot be determined by experiment. Mansouri–Sexl discussed the following synchronization schemes:
By giving the effects of time dilation and length contraction the exact relativistic value, this test theory is experimentally equivalent to special relativity, independent of the chosen synchronization. So Mansouri and Sexl spoke about the "remarkable result that a theory maintaining absolute simultaneity is equivalent to special relativity." They also noticed the similarity between this test theory and Lorentz ether theory of Hendrik Lorentz, Joseph Larmor and Henri Poincaré. Though Mansouri, Sexl, and the overwhelming majority of physicists prefer special relativity over such an aether theory, because the latter "destroys the internal symmetry of a physical theory".
Experiments with RMS.
RMS is currently used in the evaluation process of many modern tests of Lorentz invariance. To second order in "v/c", the parameters of the RMS framework have the following form:
Deviations from the two-way (round-trip) speed of light are given by:
where formula_15 is the speed of light in the preferred frame, and formula_16 is the speed of light measured in the moving frame at an angle formula_17 from the direction in which the frame is moving. To verify that special relativity is correct, the expected values of the parameters are formula_18, and thus formula_19.
The fundamental experiments to test those parameters, still repeated with increased accuracy, are:
The combination of those three experiments, together with the Poincaré–Einstein convention to synchronize the clocks in all inertial frames, is necessary to obtain the complete Lorentz transformation. Michelson–Morley only tested the combination between β and δ, while Kennedy–Thorndike tested the combination between α and β. To obtain the individual values, it's necessary to measure one of these quantities directly. This was achieved by Ives–Stilwell who measured α. So β can be determined using Kennedy–Thorndike, and subsequently δ using Michelson–Morley.
In addition to those second order tests, Mansouri and Sexl described some experiments measuring "first" order effects in "v"/"c" (such as Rømer's determination of the speed of light) as being "measurements of the one-way speed of light". These are interpreted by them as tests of the equivalence of internal synchronizations, "i.e." between synchronization by slow clock transport and by light. They emphasize that the negative results of those tests are also consistent with aether theories in which moving bodies are subject to time dilation. However, even though many recent authors agree that measurements of the equivalence of those two clock-synchronization schemes are important tests of relativity, they don't speak of "one-way speed of light" in connection with such measurements anymore, because of their consistency with non-standard synchronizations. Those experiments are consistent with all synchronizations using anisotropic one-way speeds on the basis of isotropic "two-way" speed of light and "two-way" time dilation of moving bodies.
Standard Model Extension.
Another, more extensive, model is the Standard Model Extension (SME) by Alan Kostelecký and others.
Contrary to the Roberson–Mansouri–Sexl (RMS) framework, which is kinematic in nature and restricted to special relativity, SME not only accounts for special relativity, but for dynamical effects of the standard model and general relativity as well. It investigates possible spontaneous breaking of both Lorentz invariance and CPT symmetry. RMS is fully included in SME, though the latter has a much larger group of parameters that can indicate any Lorentz or CPT violation.
For instance, a couple of SME parameters was tested in a 2007 study sensitive to 10−16. It employed two simultaneous interferometers over a year's observation: Optical in Berlin at 52°31'N 13°20'E and microwave in Perth at 31°53'S 115°53E. A preferred background (leading to Lorentz Violation) could never be at rest relative to both of them. A large number of other tests has been carried out in recent years, such as the Hughes–Drever experiments. A list of derived and already measured SME-values was given by Kostelecký and Russell.


Antonino Lo Surdo

Antonino Lo Surdo (4 February 1880 in Syracuse – 7 June 1949 in Rome) was an Italian physicist. He was appointed as professor of physics at the Istituto di Fisica in Rome in 1919; upon the death of Orso Mario Corbino in 1937, he became the director. Lo Surdo studied terrestrial physics, including seismology and geophysics; the 1908 Messina earthquake caused the death of his parents and other close relatives, except his brother. He contributed to the foundation of the Istituto Nazionale di Geofisica under the auspices of the Consiglio Nazionale delle Ricerche, when its president was Guglielmo Marconi.
His name is remembered for the discovery (made independently by Johannes Stark) in 1913 of the effect on an electric field on the emission spectrum of a gas. This physical phenomenon is called the Stark-Lo Surdo effect in Italy (and is generally known outside Italy simply as the "Stark effect"). The discovery of the effect was a remarkably important contribution to the development of the quantum theory. Lo Surdo's discovery of the effect led Antonio Garbasso to introduce quantum theory into the Italian universities.


Lowitz arc

A Lowitz arc is an optical phenomenon that occurs in the atmosphere; specifically, it is a rare type of ice crystal halo that forms a luminous arc which extends inwards from a sun dog (parhelion) and may continue above or below the sun.
History.
The phenomenon is named after (or Lovits) (1757 - 1804), a German-born Russian apothecary and experimental chemist. On the morning of June 18, 1790 in St. Petersburg, Russia, Lowitz witnessed a spectacular display of solar halos. Among his observations, he noted arcs descending from the sun dogs and extending below the sun:
Original (in French): "6. Ces deux derniers parhélies qui se trouvoient à quelque distance des intersections du grand cercle horizontal par les deux couronnes qui entourent le soleil, renvoyoient d'abord des deux cotés de parties d'arc très courtes colorées "xi" & "yk" dont la direction s'inclinoit au dessous du soleil jusqu'aux deux demi-arcs de cercle intérieurs "die" & "dke". En second lieu ils étoient pourvues des queues longues, claires & blanches "x ζ" & "y η" , opposées au soleil & renfermées dans la circonference du grand cercle "afbg"."
"Translation" : 6. These last two parhelia which were at some distance from the intersections of the great horizontal circle by the two coronas which surrounded the sun, sent, in the first place, from the two sides very short colored arcs "xi" & "yk" whose direction inclined below the sun as far as the two interior semicircular arcs "die" & "dke". In the second place, they had long tails, bright and white "x ζ" & "y η" , directed away from the sun and included in the circumference of the great circle "afhg".
Lowitz formally reported the phenomenon to the St. Petersburg Academy of Sciences on October 18, 1790, including a detailed illustration of what he had witnessed. The illustration included what are now called “lower Lowitz arcs”.
However, some scientists (not unreasonably) doubted the existence of the phenomenon: the phenomenon rarely occurs; and since Lowitz arcs were little known, people who witnessed them didn’t always recognize them; furthermore, until the advent of small, inexpensive digital cameras, witnesses rarely had, at hand, cameras to record them, and even if they did have cameras, the cameras weren’t always sensitive enough to record the faint Lowitz arcs. Only since circa 1990 have photographs of what are clearly Lowitz arcs become available for study and analysis.
The phenomenon and hypotheses about its cause.
Sometimes, when the sun is low in the sky, there are luminous spots to the left and right of the sun and at the same elevation as the sun. These luminous spots are called "sun dogs" or "parhelia". (Often on these occasions, the sun is also surrounded by a luminous ring or halo, the angle between the sun and the halo (with the observer at the angle’s vertex) measuring 22°.) On rare occasions, faint arcs extend upwards or downwards from these sun dogs. These arcs extending from the sun dogs are "Lowitz arcs". As many as three distinct arcs may extend from the sun dogs. The short arc that first inclines towards the sun and then extends downward is called the "lower Lowitz arc". A longer second arc may also extend downward from the sun dog but then curve under the sun, perhaps joining the other sun dog; this is the "middle Lowitz arc" or "circular Lowitz arc". Finally, a third arc may extend upwards from the sun dog; this is the "upper Lowitz arc". In his diagram of 1790, Lowitz recorded only a lower Lowitz arc.
Like the 22° solar halo and sun dogs, Lowitz arcs are believed to be caused by sunlight refracting (bending) through ice crystals. However, there still remains some dispute about the shape and orientation of the ice crystals that produce Lowitz arcs.
In 1840, the German astronomer Johann Gottfried Galle (1812 - 1910) proposed that lower Lowitz arcs were produced as sun dogs are; that is, by sunlight refracting through hexagonal ice crystals. However, in the case of sun dogs, the columnar crystals are oriented vertically, whereas in the case of Lowitz arcs, Galle proposed, the crystals oscillated about their vertical axes.
Charles Sheldon Hastings (1848 - 1932), an American physicist who specialized in optics, suggested in 1901 that Lowitz arcs were due to hexagonal plates of ice, which oscillated around a horizontal axis in the plane of the plate as the plate fell, similar to the fluttering of a falling leaf. Later, in 1920, he proposed that the plates rotate, rather than merely oscillate, around their long diagonals.
According to Hastings, sunlight enters one of the faces on the edge of the plate, is refracted, propagates through the ice crystal, and then exits through another face on the edge of the plate, which is at 60° to the first face, refracts again as it exits, and finally reaches the observer. Because the ice plates rotate, plates throughout an arc are—at some time during each rotation—oriented to refract sunlight to the observer. A hexagonal plate has three long diagonals about which it can rotate, but rotation around only one of the axes causes the lower Lowitz arc. The other Lowitz arcs—the middle and upper arcs—are caused by sunlight passing through the two other pairs of faces of the hexagonal ice plate.
However, since circa 1990, photographs of what are clearly Lowitz arcs have become available for study. Furthermore, numerical ray-tracing software allows Lowitz arcs to be simulated by computers, so that, from hypotheses about the shape and orientation of ice crystals, the shape and intensity of a hypothetical Lowitz arc can be predicted and compared against photographs of actual arcs. As a result of such simulations, the traditional explanation of Lowitz arcs has been found to have some shortcomings. Specifically, simulations assuming that only perfectly hexagonal, rotating plates produce Lowitz arcs, predict the wrong intensities for the arcs. More accurate simulations were obtained by assuming that the plates were almost horizontal, or that the ice crystals had a more rhombic shape or were hexagonal columns that were oriented horizontally.
Hence the exact mechanism by which Lowitz arcs are produced, remains unresolved.


List of finite-dimensional Nichols algebras

In mathematics, a Nichols algebra is a Hopf algebra in a braided category assigned to an object "V" in this category (e.g. a braided vector space). The Nichols algebra is a quotient of the tensor algebra of "V" enjoying a certain universal property and is typically infinite-dimensional. Nichols algebras appear naturally in any pointed Hopf algebra and enabled their classification in important cases. The most well known examples for Nichols algebras are the Borel parts formula_1 of the infinite-dimensional quantum groups when "q" is no root of unity, and the first examples of finite-dimensional Nichols algebras are the Borel parts formula_2 of the Frobenius–Lusztig kernel ("small quantum group") when "q" is a root of unity.
The following article lists all known finite-dimensional Nichols algebras formula_3 where formula_4 is a Yetter–Drinfel'd module over a finite group formula_5, where the group is generated by the support of formula_4. For more details on Nichols algebras see Nichols algebra.
Note that a Nichols algebra only depends on the braided vector space formula_4 and can therefore be realized over many different groups. Sometimes there are two or three Nichols algebras with different formula_4 and non-isomorphic Nichols algebra, which are closely related (e.g. cocycle twists of each other). These are given by different conjugacy classes in the same column.
State of classification.
Negative criteria.
The case of rank 1 (irreducible Yetter–Drinfel'd module) over a nonabelian group is still largely open, with few examples known.
Much progress has been made by Andruskiewitsch and others by finding subracks (for example diagonal ones) that would lead to infinite-dimensional Nichols algebras. As of 2015, known groups not admitting finite-dimensional Nichols algebras are
Usually a large amount of conjugacy classes ae of type D ("not commutative enough"), while the others tend to possess sufficient abelian subracks and can be excluded by their consideration. Several cases have to be done by-hand. Note that the open cases tend to have very small centralizers (usually cyclic) and representations χ (usually the 1-dimensional sign representation). Significant exceptions are the conjugacy classes of order 16, 32 having as centralizers p-groups of order 2048 resp. 128 and currently no restrictions on χ.
Over abelian groups.
Finite-dimensional diagonal Nichols algebras over the complex numbers were classified by Heckenberger in in terms of the braiding matrix formula_31, more precisely the data formula_32. The small quantum groups formula_2 are a special case formula_34, but there are several exceptional examples involving the primes 2,3,4,5,7.
Recently there has been progress understanding the other examples as exceptional Lie algebras and super-Lie algebras in finite characteristic.
Over nonabelian group, rank > 1.
Nichols algebras from Coxeter groups.
For every finite coxeter system formula_35 the Nichols algebra over the conjugacy class(es) of reflections was studied in (reflections on roots of different length are not conjugate, see fourth example fellow). They discovered in this way the following first Nichols algebras over nonabelian groups :
The case formula_36 is the rank 1 diagonal Nichols algebra formula_37 of dimension 2.
Nichols algebras of rank 2, type Gamma-3.
These Nichols algebras were discovered during the classification of Heckenberger and Vendramin.
The Nichols algebra of rank 2 type Gamma-4.
 This Nichols algebra was discovered during the classification of Heckenberger and Vendramin.
The Nichols algebra of rank 2, type T.
 This Nichols algebra was discovered during the classification of Heckenberger and Vendramin.
The Nichols algebra of rank 3 involving Gamma-3.
 This Nichols algebra was the last Nichols algebra discovered during the classification of Heckenberger and Vendramin.
Nichols algebras from diagram folding.
The following families Nichols algebras were constructed by Lentner using diagram folding, the fourth example appearing only in characteristic 3 was discovered during the classification of Heckenberger and Vendramin.
The construction start with a known Nichols algebra (here diagonal ones related to quantum groups) and an additional automorphism of the Dynkin diagram. Hence the two major cases are whether this automorphism exchanges two disconnected copies or is a proper diagram automorphism of a connected Dynkin diagram. The resulting root system is folding / restriction of the original root system. By construction, generators and relations are known from the diagonal case.
The following two are obtained by proper automorphisms of the connected Dynkin diagrams formula_38
Note that there are several more foldings, such as formula_39 and also some not of Lie type, but these violate the condition that the support generates the group.


Isovector

In particle physics, isovector refers to the vector transformation of a particle under the SU(2) group of isospin. An isovector state is a triplet state with total isospin 1, with the third component of isospin either 1, 0, or -1, much like a triplet state in the two-particle addition of Spin.
See also Isoscalar.


Daniel E. Hastings

Daniel E. Hastings is an American physicist, currently the Cecil and Ida Green Education Professor and the former director of the Singapore-MIT Alliance for Research and Technology (SMART) at the Massachusetts Institute of Technology. Hastings became head of the Department of Aeronautics and Astronautics on January 1, 2019. He has served as the Chief Scientist of the US Air Force and on many national level boards.
Dr. Hastings earned his B.A. at Oxford University in the UK (1976) and his S.M. (1978) and Ph.D. (1980) at the Massachusetts Institute of Technology, writing his doctoral thesis on "The high‐β universal drift mode."
Dr. Hastings was an associate professor (1980-1993) and later full professor for the Department of Aeronautics and Astronautics at MIT (1993-present). He was also the associate department head of research (1993-1996). He took a short sabbatical to be the Chief Scientist of the US Air Force (1997-1999) and served on the National Science Board from 2002-2008. Dr. Hastings was asked to direct the Technology and Policy Program (TPP) at MIT (2000-2003) as well as associate director and co-director of the Engineering Systems Division (2000-2004), and later became its director (2004-2005). Dr. Hastings became the Dean for Undergraduate Education (2006-2013) and then the CEO and Director of the Singapore-MIT Alliance for Research and Technology (2014-2018). As of January 1, 2019, he is the head of the Department of Aeronautics and Astronautics. Dr. Hastings has received many honors, including membership to the National Academy of Engineering (2017), fellowship in the Institute of the Aeronautical Sciences (1998), and the Air Force Distinguished Civilian Award (1997, 1999).
Academic work.
Dr. Hastings has published extensively in aerospace engineering, including a highly cited textbook called "Spacecraft-environment interactions". His research includes uncertainty and systems' engineering.


Fixed-field alternating gradient accelerator

A Fixed-Field alternating gradient Accelerator (FFA) is a circular particle accelerator concept on which development was started in the early 50s, and that can be characterized by its time-independent magnetic fields ("fixed-field", like in a cyclotron) and the use of strong focusing ("alternating gradient", like in a synchrotron). Thus, FFA accelerators combine the cyclotron's advantage of continuous, unpulsed operation, with the synchrotron's relatively inexpensive small magnet ring, of narrow bore.
Although the development of FFAs had not been pursued for over a decade starting from 1967, interest has been revived since the mid-1980s for usage in neutron spallation sources, as a driver for muon colliders and to accelerate muons in a neutrino factory since the mid-1990s.
The revival in FFA research has been particularly strong in Japan with the construction of several rings. This resurgence has been prompted in part by advances in RF cavities and in magnet design.
We note that the acronym for Fixed-Field alternating gradient Accelerator has recently changed from FFAG to FFA. Thus, when searching older literature, one will find more often the original acronym of FFAG.
History.
First development phase.
The idea of fixed-field alternating-gradient synchrotrons was developed independently in Japan by Tihiro Ohkawa, in the United States by Keith Symon, and in Russia by Andrei Kolomensky. The first prototype, built by Lawrence W. Jones and Kent M. Terwilliger at the University of Michigan used betatron acceleration and was operational in early 1956. That fall, the prototype was moved to the Midwestern Universities Research Association (MURA) lab at University of Wisconsin, where it was converted to a 500 keV electron synchrotron. Symon's patent, filed in early 1956, uses the terms "FFAG accelerator" and "FFAG synchrotron". Ohkawa worked with Symon and the MURA team for several years starting in 1955.
Donald Kerst, working with Symon, filed a patent for the spiral-sector FFA accelerator at around the same time as Symon's Radial Sector patent. A very small spiral sector machine was built in 1957, and a 50 MeV radial sector machine was operated in 1961. This last machine was based on Ohkawa's patent, filed in 1957, for a symmetrical machine able to simultaneously accelerate identical particles in both clockwise and counterclockwise beams. This was one of the first colliding beam accelerators, although this feature was not used when it was put to practical use as the injector for the Tantalus storage ring at what would become the Synchrotron Radiation Center. The 50MeV machine was finally retired in the early 1970s.
MURA designed 10 GeV and 12.5 GeV proton FFAs that were not funded. Two scaled down designs, one for 720 MeV and one for a 500 MeV injector, were published.
With the shutdown of MURA which began 1963 and ended 1967, the FFA concept was not in use on an existing accelerator design and thus was not actively discussed for some time.
Continuing development.
In the early 1980s, it was suggested by Phil Meads that an FFA was suitable and advantageous as a proton accelerator for an intense spallation neutron source, starting off projects like the Argonne Tandem Linear Accelerator at Argonne National Laboratory and the Cooler Synchrotron at Jülich Research Centre.
Conferences exploring this possibility were held at Jülich Research Centre, starting from 1984. There have also been numerous annual workshops focusing on FFA accelerators at CERN, KEK, BNL, TRIUMF, Fermilab, and the Reactor Research Institute at Kyoto University. In 1992, the European Particle Accelerator Conference at CERN was about FFA accelerators.
The first proton FFA was successfully construction in 2000, initiating a boom of FFA activities in high-energy physics and medicine.
With superconducting magnets, the required length of the FFA magnets scales roughly as the inverse square of the magnetic field. In 1994, a coil shape which provided the required field with no iron was derived. This magnet design was continued by S. Martin "et al." from Jülich.
In 2010, after the workshop on FFA accelerators in Kyoto, the construction of the Electron Machine with Many Applications (EMMA) was completed at Daresbury Laboratory, UK. This was the first non-scaling FFA accelerator. Non-scaling FFAs are often advantageous to scaling FFAs because large and heavy magnets are avoided and the beam is much better controlled.
Scaling vs non-scaling types.
The magnetic fields needed for an FFA are quite complex. The computation for the magnets used on the Michigan FFA Mark Ib, a radial sector 500 keV machine from 1956, were done by Frank Cole at the University of Illinois on a mechanical calculator built by Friden. This was at the limit of what could be reasonably done without computers; the more complex magnet geometries of spiral sector and non-scaling FFAs require sophisticated computer modeling.
The MURA machines were scaling FFA synchrotrons meaning that orbits of any momentum are photographic enlargements of those of any other momentum. In such machines the betatron frequencies are constant, thus no resonances, that could lead to beam loss, are crossed. A machine is scaling if the median plane magnetic field satisfies
where
For formula_8 an FFA magnet is much smaller than that for a cyclotron of the same energy. The disadvantage is that these machines are highly nonlinear. These and other relationships are developed in the paper by Frank Cole.
The idea of building a non-scaling FFA first occurred to Kent Terwilliger and Lawrence W. Jones in the late 1950s while thinking about how to increase the beam luminosity in the collision regions of the 2-way colliding beam FFA they were working on. This idea had immediate applications in designing better focusing magnets for conventional accelerators, but was not applied to FFA design until several decades later.
If acceleration is fast enough, the particles can pass through the betatron resonances before they have time to build up to a damaging amplitude. In that case the dipole field can be linear with radius, making the magnets smaller and simpler to construct. A proof-of-principle "linear, non-scaling" FFA called (EMMA) (Electron Machine with Many Applications) has been successfully operated at Daresbury Laboratory, UK.
Vertical FFAs.
Vertical Orbit Excursion FFAs (VFFAs) are a special type of FFA arranged so that higher energy orbits occur above (or below) lower energy orbits, rather than radially outward. This is accomplished with skew-focusing fields that push particles with higher beam rigidity vertically into regions with a higher dipole field.
The major advantage offered by a VFFA design over a FFA design is that the path-length is held constant between particles with different energies and therefore relativistic particles travel isochronously. Isochronicity of the revolution period enables continuous beam operation, therefore offering the same advantage in power that isochronous cyclotrons have over synchrocyclotrons. Isochronous accelerators have no longitudinal beam focusing, but this is not a strong limitation in accelerators with rapid ramp rates typically used in FFA designs.
The major disadvantages include the fact that VFFAs requires unusual magnet designs and currently VFFA designs have only been simulated rather than tested.
Applications.
FFA accelerators have potential medical applications in proton therapy for cancer, as proton sources for high intensity neutron production, for non-invasive security inspections of closed cargo containers, for the rapid acceleration of muons to high energies before they have time to decay, and as "energy amplifiers", for Accelerator-Driven Sub-critical Reactors (ADSRs) / Sub-critical Reactors in which a neutron beam derived from a FFA drives a slightly sub-critical fission reactor. Such ADSRs would be inherently safe, having no danger of accidental exponential runaway, and relatively little production of transuranium waste, with its long life and potential for nuclear weapons proliferation.
Because of their quasi-continuous beam and the resulting minimal acceleration intervals for high energies, FFAs have also gained interest as possible parts of future muon collider facilities.
Status.
In the 1990s, researchers at the KEK particle physics laboratory near Tokyo began developing the FFA concept, culminating in a 150 MeV machine in 2003. A non-scaling machine, dubbed PAMELA, to accelerate both protons and carbon nuclei for cancer therapy has been designed. Meanwhile, an ADSR operating at 100 MeV was demonstrated in Japan in March 2009 at the Kyoto University Critical Assembly (KUCA), achieving "sustainable nuclear reactions" with the critical assembly's control rods inserted into the reactor core to damp it below criticality.


Robert Bellamy Clifton

Robert Bellamy Clifton FRS (13 March 1836 – 21 February 1921) was a British scientist.
Academic career.
Clifton was educated at University College, London and St Johns College, Cambridge where he studied under Sir George Stokes.
In 1860 he went to Owens College, Manchester as Professor of Natural Philosophy. In 1865 he was appointed Professor of experimental Natural Philosophy at Oxford University. While at Oxford he designed Clarendon Laboratory and gave research space to Charles Vernon Boys.
On 4 June 1868 he became a fellow of the Royal Society.
He was president of the Physical Society (now Institute of Physics) from 1882 until 1884. From 1868 until his retirement in 1915 he was a Fellow of Merton College, Oxford.
Family.
Clifton's father was the clergyman Robert Cox Clifton. His daughter Catharine Edith was married to the surgeon Henry Souttar.