WorldWideScience

Sample records for antimatter driven p-b11

  1. Antimatter Driven P-B11 Fusion Propulsion System

    Science.gov (United States)

    Kammash, Terry; Martin, James; Godfroy, Thomas

    2002-01-01

    One of the major advantages of using P-B11 fusion fuel is that the reaction produces only charged particles in the form of three alpha particles and no neutrons. A fusion concept that lends itself to this fuel cycle is the Magnetically Insulated Inertial Confinement Fusion (MICF) reactor whose distinct advantage lies in the very strong magnetic field that is created when an incident particle (or laser) beam strikes the inner wall of the target pellet. This field serves to thermally insulate the hot plasma from the metal wall thereby allowing thc plasma to burn for a long time and produce a large energy magnification. If used as a propulsion device, we propose using antiprotons to drive the system which we show to be capable of producing very large specific impulse and thrust. By way of validating the confinement propenies of MICF we will address a proposed experiment in which pellets coated with P-B11 fuel at the appropriate ratio will be zapped by a beam of antiprotons that enter the target through a hole. Calculations showing the density and temperature of the generated plasma along with the strength of the magnetic field and other properties of the system will be presented and discussed.

  2. Puzzling antimatter

    CERN Multimedia

    Francesco Poppi

    2010-01-01

    For many years, the absence of antimatter in the Universe has tantalised particle physicists and cosmologists: while the Big Bang should have created equal amounts of matter and antimatter, we do not observe any primordial antimatter today. Where has it gone? The LHC experiments have the potential to unveil natural processes that could hold the key to solving this paradox.   Every time that matter is created from pure energy, equal amounts of particles and antiparticles are generated. Conversely, when matter and antimatter meet, they annihilate and produce light. Antimatter is produced routinely when cosmic rays hit the Earth's atmosphere, and the annihilations of matter and antimatter are observed during physics experiments in particle accelerators. If the Universe contained antimatter regions, we would be able to observe intense fluxes of photons at the boundaries of the matter/antimatter regions. “Experiments measuring the diffuse gamma-ray background in the Universe would be able...

  3. Antimatter Experiments

    CERN Multimedia

    2004-01-01

    Antimatter should behave in identical fashion to matter if a form of spacetime symmetry called CPT invariance holds. Two experiments at CERN near Geneva are testing this hypothesis using antihydrogen atoms

  4. Antimatter Matters

    CERN Multimedia

    CERN

    2016-01-01

    This video is a teaser-introduction to the Antimatter Matters exhibtion at the Royal Society's Summer Science exhibition July 4-10 2016. The exhibition is jointly organised and hosted by UK members of the ALPHA and LHCb collaborations.

  5. Antimatter underestimated

    CERN Document Server

    Gsponer, A; Gsponer, Andre; Hurni, Jean-Pierre

    1987-01-01

    We warn of the potential nuclear proliferation's consequences of military applications of nano- or microgram amounts of antimatter, such as triggering of high-yield thermonuclear explosions, laser pumping, compact sources of energy, directed-energy beams, and portable sources of muons.

  6. Baryogenesis and cosmological antimatter

    CERN Document Server

    Dolgov, A D

    2009-01-01

    Possible mechanisms of baryogenesis are reviewed. Special attention is payed to those which allow for creation of astronomically significant domains or objects consisting of antimatter. Observational manifestations of cosmological antimatter are discussed.

  7. Antimatter brochure (English version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    Antimatter is the twin to matter, with an opposite electric charge. When they meet, they annihilate each other. In the first moments of the Universe there was a balance between antimatter and matter, but a second after the Big Bang, all the antimatter disappeared along with almost all of the matter, leaving a minute amount of matter that forms everything around us. Scientists are now trying to unravel the mystery of what happened to the antimatter.

  8. Antimatter brochure (French)

    CERN Multimedia

    Lefevre, C

    2009-01-01

    Antimatter is the twin to matter, with an opposite electric charge. When they meet, they annihilate each other. In the first moments of the Universe there was a balance between antimatter and matter, but a second after the Big Bang, all the antimatter disappeared along with almost all of the matter, leaving a tiny amount of matter that forms everything around us. Scientists are now trying to unravel the mystery of what happened to the antimatter.

  9. Antimatter brochure (German version)

    CERN Multimedia

    Lefevre, C

    2009-01-01

    Antimatter is the twin to matter, with an opposite electric charge. When they meet, they annihilate each other. In the first moments of the Universe there was a balance between antimatter and matter, but a second after the Big Bang, all the antimatter disappeared along with almost all of the matter, leaving a minute amount of matter that forms everything around us. Scientists are now trying to unravel the mystery of what happened to the antimatter.

  10. Antimatter brochure (English)

    CERN Multimedia

    Lefevre, C

    2009-01-01

    Antimatter is the twin to matter, with an opposite electric charge. When they meet, they annihilate each other. In the first moments of the Universe there was a balance between antimatter and matter, but a second after the Big Bang, all the antimatter disappeared along with almost all of the matter, leaving a minute amount of matter that forms everything around us. Scientists are now trying to unravel the mystery of what happened to the antimatter.

  11. The antimatter gravitational field

    CERN Document Server

    Chiarelli, Piero

    2015-01-01

    In this work the author derives the Galilean limit of the gravitational field of antimatter by using the hydrodynamic quantum gravity equations that comprehend the antiparticle impulse-energy tensor. The result shows that, even the antimatter mass is a positive valued quantity, its presence gives a negative 4-d space curvature respect to that one of the matter as a consequence of the backward propagation in time of the antimatter wave function. The result leads to the consequence that the null space curvature of photons undergoing to electron-positron couples generation (or annihilation) does not change during the process. A laboratory experiment to validate the theory output is also proposed .

  12. Searching for Primordial Antimatter

    Science.gov (United States)

    2008-10-01

    Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot

  13. Antimatter in the classroom

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    A brand new teaching resource has just been made available on the CERN Education website. The Antimatter Teaching Module contains eight lesson plans, together with background materials and extension topics, which are part of a wide educational project whose aim is to stimulate interest in science by introducing themes in modern physics to students aged 14-15 years, that is, earlier than is the practice in most national curricula. Terrence Baine (left) and Rolf Landua (right) with an antimatter trap from the film 'Angels & Demons'. In his capacity as CERN’s first Teacher in Residence, Terrence Baine’s primary project was to develop teaching modules to help high school teachers around the world incorporate modern particle physics into their curricula. “Back in October, it was decided that the first module should be on antimatter”, explains Terrence, who worked on it in collaboration with Rolf Landua, head of the Education Group and antimatter expert. “...

  14. Antimatter cancer treatment

    CERN Multimedia

    Van Noorden, Richard

    2006-01-01

    "The idea that antimatter beams could treat cancer might seem ridiculous. But researchers working at Cerns particle accelerator laboratory in Geneva don't think so. They have just reported a successful first experiment into the biological effects of antiprotons radiation on living cells."

  15. Matter-antimatter asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The Conference is devoted to a multidisciplinary study of matter-antimatter asymmetry and, in particular, from the point of view of particle physics, astrophysics and cosmology. A number of topics, such as the practical applications of antimatter in medical imaging, of particular interest to non-specialists, will also be briefly covered. More than thirty years after the discovery of CP violation in the kaon system, precision experiments with kaons at CERN and Fermilab have demonstrated the existence of direct CP violation, opening a window on a hitherto poorly explored part of particle physics. On the one hand, two experiments devoted mainly to CP violation in B mesons, BABAR and Belle, are beginning to test CP violation in the Standard Model in a decisive way. On the other hand, balloon experiments and the space-based AMS project are circumscribing precise limits on the cosmological abundance of antimatter. Finally, the fundamental problem of cosmological matter-antimatter asymmetry at a Grand Unification scale or at the Electroweak phase transition has been the object of intense theoretical activity in recent years. This document gathers most of the slides that have been presented in the plenary and parallel sessions.

  16. Antimatter gravity with muonium

    OpenAIRE

    kaplan, Daniel M.; Fischbach, Ephraim; Kirch, Klaus; Mancini, Derrick C.; Phillips, James D.; Phillips, Thomas J.; Reasenberg, Robert D; Roberts, Thomas J.; Terry, Jeff

    2016-01-01

    The gravitational acceleration of antimatter, $\\bar{g}$, has never been directly measured and could bear importantly on our understanding of gravity, the possible existence of a fifth force, and the nature and early history of the universe. Three avenues appear feasible for such a measurement: antihydrogen, positronium, and muonium. The muonium measurement requires a novel monoenergetic, low-velocity, horizontal muonium beam directed at an atom interferometer. The precision three-grating inte...

  17. Antimatter gravity with muonium

    CERN Document Server

    Kaplan, Daniel M; Kirch, Klaus; Mancini, Derrick; Phillips, James D; Phillips, Thomas J; Reasenberg, Robert D; Roberts, Thomas J; Terry, Jeff

    2016-01-01

    The gravitational acceleration of antimatter, $\\bar{g}$, has never been directly measured and could bear importantly on our understanding of gravity, the possible existence of a fifth force, and the nature and early history of the universe. Three avenues appear feasible for such a measurement: antihydrogen, positronium, and muonium. The muonium measurement requires a novel monoenergetic, low-velocity, horizontal muonium beam directed at an atom interferometer. The precision three-grating interferometer can be produced in silicon nitride or ultrananocrystalline diamond using state-of-the-art nanofabrication. The required precision alignment and calibration at the picometer level also appear to be feasible. With 100 nm grating pitch, a 10% measurement of $\\bar{g}$ can be made using some months of surface-muon beam time, and a 1% or better measurement with a correspondingly larger exposure. This could constitute the first gravitational measurement of leptonic matter, of 2nd-generation matter and, possibly, the f...

  18. Antimatter performs optical gymnastics

    Energy Technology Data Exchange (ETDEWEB)

    Eades, John [University of Tokyo (Japan); CERN, Geneva (Switzerland)

    2005-03-01

    Lasers have been used for the first time to create antihydrogen, which could allow precise spectroscopic measurements of anti-atoms. The philosopher William James once said that 'if you wish to upset the law that all crows are black, you must not seek to show that none of them are - it is enough to produce a single white crow'. Likewise, if you wish to test the so-called CPT theorem, according to which a world constructed of antimatter behaves exactly the same as one constructed of matter, you do not need to create an entire 'antiworld'. It would be quite sufficient to show that the frequency of just one transition in a simple anti-atom differs from the value of the same transition in the corresponding ordinary atom. The question is, by how much? Any gross violations of the CPT theorem - which, more formally, states that a system remains unchanged under the combined operations of charge conjugation, parity reversal and time reversal - have already been ruled out experimentally. As a result, nobody expects any difference between matter and antimatter to be anything other than minute, if, indeed, there is a difference at all. The laser-spectroscopy tools that have made it possible to measure transition frequencies in ordinary hydrogen to extraordinarily high precision should also be applicable to antihydrogen. This makes hydrogen anti-atoms excellent candidates to test the CPT theorem. Now, researchers in the ATRAP collaboration at CERN have taken an important step along the obstacle-strewn path towards this goal by using lasers to control the production of antihydrogen atoms. (U.K.)

  19. Antimatter and Time-Symmetry

    CERN Document Server

    Pitts, T

    1998-01-01

    This theory makes time symmetric by Weyl's definition; it hypothesizes that space, time and mass-energy expand outward from the Big Bang along the time axis equally in the (+-) and (-) directions. In the Feynman-Stueckelberg Interpretation, antimatter is identical to matter but moves backward in time. This essay argues that this interpretation is physically real via an analysis of the time-symmetry of the Schrodinger equation. As time expands from zero, in both directions in time away from the origin, quantum uncertainty allows a brief, decreasing leakage of mass between (+-) and (-) universes. Matter leaking from (-) to (+-) time moves forward in time, producing a preponderance of matter in (+-) time. Antimatter leakage from (+-) time to (-) time in the same way produces an antimatter preponderance in the (-) time universe. The remaining opposite particles left behind after the leakage, (antimatter and matter respectively) proceeding outward in antitime and time respectively, after many annihilations also in...

  20. Gravitational Repulsion and Dirac Antimatter

    Science.gov (United States)

    Kowitt, Mark E.

    1996-03-01

    Based on an analogy with electron and hole dynamics in semiconductors, Dirac's relativistic electron equation is generalized to include a gravitational interaction using an electromagnetic-type approximation of the gravitational potential. With gravitational and inertial masses decoupled, the equation serves to extend Dirac's deduction of antimatter parameters to include the possibility of gravitational repulsion between matter and antimatter. Consequences for general relativity and related “antigravity” issues are considered, including the nature and gravitational behavior of virtual photons, virtual pairs, and negative-energy particles. Basic cosmological implications of antigravity are explored—in particular, potential contributions to inflation, expansion, and the general absence of detectable antimatter. Experimental and observational tests are noted, and new ones suggested.

  1. The gravitational properties of antimatter

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, T.; Hughes, R.J.; Nieto, M.M.

    1986-09-01

    It is argued that a determination of the gravitational acceleration of antimatter towards the earth is capable of imposing powerful constraints on modern quantum gravity theories. Theoretical reasons to expect non-Newtonian non-Einsteinian effects of gravitational strength and experimental suggestions of such effects are reviewed. 41 refs. (LEW)

  2. Measuring Antimatter Gravity with Muonium

    CERN Document Server

    Kaplan, Daniel M; Phillips, Thomas J; Roberts, Thomas J; Gustafson, Richard

    2013-01-01

    We consider a measurement of the gravitational acceleration of antimatter, gbar, using muonium. A monoenergetic, low-velocity, horizontal muonium beam will be formed from a surface-muon beam using a novel technique and directed at an atom interferometer. The measurement requires a precision three-grating interferometer: the first grating pair creates an interference pattern which is analyzed by scanning the third grating vertically using piezo actuators. State-of-the-art nanofabrication can produce the needed membrane grating structure in silicon nitride or ultrananoscrystalline diamond. With 100 nm grating pitch, a 10% measurement of gbar can be made using some months of surface-muon beam time. This will be the first gravitational measurement of leptonic matter, of 2nd-generation matter and, possibly, the first measurement of the gravitational acceleration of antimatter.

  3. Measuring Antimatter Gravity with Muonium

    OpenAIRE

    Kaplan Daniel M.; Kirch Klaus; Mancini Derrick; Phillips James D.; Phillips Thomas J.; Roberts Thomas J.; Terry Jeff

    2013-01-01

    The gravitational acceleration of antimatter, $\\bar{g}$, has never been directly measured and could bear importantly on our understanding of gravity, the possible existence of a fifth force, and the nature and early history of the universe. Only two avenues for such a measurement appear to be feasible: antihydrogen and muonium. The muonium measurement requires a novel, monoenergetic, low-velocity, horizontal muonium beam directed at an atom interferometer. The precision three-grating interfer...

  4. Antimatter: (Latest citations from the INSPEC Database)

    Science.gov (United States)

    1997-04-01

    The bibliography contains citations concerning physical theory, testing, and practical applications of antimatter. Related nuclear phenomena, matter-antimatter interactions, relativity, antigravity, formation of the universe, and space-time configurations are described. The roles of cosmic rays, black holes, antiprotons, and positrons are discussed. Antimatter propulsion spacecraft are briefly cited. (Contains 50-250 citations and includes a subject term index and title list.)

  5. Antimatter. (Latest citations from the INSPEC Database)

    Science.gov (United States)

    1996-01-01

    The bibliography contains citations concerning physical theory, testing, and practical applications of antimatter. Related nuclear phenomena, matter-antimatter interactions, relativity, antigravity, formation of the universe, and space-time configurations are described. The roles of cosmic rays, black holes, antiprotons, and positrons are discussed. Antimatter propulsion spacecraft are briefly cited. (Contains 50-250 citations and includes a subject term index and title list.)

  6. Antimatter: Its history and its properties

    International Nuclear Information System (INIS)

    We review the conceptual developments of quantum theory and special relativity which culminated in the discovery of and understanding of antimatter. In particular, we emphasize how quantum theory and special relativity together imply that antimatter must exist. Our modern understanding of antimatter is summarized in the CPT theorem of relativistic quantum field theory. The implications of this theorem have never been contradicted by any experiment ever done. 38 refs

  7. Why antihydrogen and antimatter are different

    CERN Document Server

    Zichichi, Antonino

    2009-01-01

    As Paul Dirac realized, the existence of antihydrogen does not in itself prove the existence of antimatter. A look through the history of the subject, and in particular the role played by the CPT theorem, shows that ultimately it came down to experiment to prove the existence of antimatter through the discovery of the antideuteron at CERN in 1965.

  8. Observation of the antimatter helium-4 nucleus

    NARCIS (Netherlands)

    Agakishiev, H.; Aggarwal, M.M.; Braidot, E; Peitzmann, T.; Zoulkarneeva, Y.

    2011-01-01

    High-energy nuclear collisions create an energy density similar to that of the Universe microseconds after the Big Bang1; in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quick

  9. Golden Jubilee photos: Gathering Antimatter

    CERN Multimedia

    2004-01-01

    One day, antimatter might take people where no one has gone before, but it isn't science fiction. Protons are easily obtainable by stripping electrons from hydrogen atoms, but their antimatter counterparts, the antiprotons, have to be created artificially at accelerators. Roughly one antiproton can be produced from around a million protons bombarding a target at 26 GeV. In 1978, when CERN decided to take the unprecedented step of turning the SPS accelerator into a proton-antiproton collider, it had to deal with the scarcity, and had to concentrate the beam until it was intense enough for the experiment. Antiprotons are produced with a wide range of angles and energy, so before they can be used in an accelerator they have to be captured and 'cooled', reducing the beam dimensions by many orders of magnitude. This was the job of the Antiproton Accumulator (AA), completed in 1980 and shown here before it disappeared from view under concrete shielding. It followed the pioneering Initial Cooling Experiment (ICE) i...

  10. Plasmas as the Drivers for Science with Antimatter

    Science.gov (United States)

    Surko, Clifford M.

    2010-11-01

    Progress and future challenges in physics and technology with antimatter (positrons and antiprotons) will be described illustrating the important role played by plasma science [1]. Topics include the creation and study of antihydrogen (stable, neutral antimatter) [2,3] and the positronium molecule (e^+e^-e^+e^-) [4]; plans to study electron-positron plasmas [5]; the quest for a BEC gas of positronium atoms; positron binding to atoms and molecules [6]; the development of new types of positron beams for materials studies; and prospects for commercial positron traps and beams. Much of this progress has been driven by the development of new plasma techniques. Efficient positron accumulation is obtained using specially designed Penning-Malmberg traps with trapping and cooling provided by molecular gases. Plasmas are compressed radially using rotating electric fields. Long-term storage and cooling to cryogenic temperatures are obtained using traps in UHV environments in several-tesla magnetic fields [2,3]. A method to increase trap capacity by orders of magnitude will be described [7]. Prospects for portable antimatter traps and other exceedingly challenging projects such as a Ps-atom interferometer and an annihilation gamma ray laser will be discussed. Efforts to understand the behavior of antimatter in astrophysical settings will also be discussed. A sampling of references (by 1st author): [1] C. M. Surko, Phys. Pl. 11, 2333 ('04); [2] G. Gabrielse, Physics Today, Mar. ('10), 68; [3] G. B. Andresen, Phys. Rev. Lett. 105, 013003 ('10); [4] D. B. Cassidy, Nature 449, 195 ('07); [5] T. S. Pedersen, Fus. Sci. Tech., 50, 372 ('06); [6] G. F. Gribakin, Rev. Mod. Phys., in press ('10); [7] J. R. Danielson, AIP Conf. Proc. 1114 ('09), 199.

  11. More Sci- than Fi, Physicists Create Antimatter

    CERN Multimedia

    Overbye, Dennis

    2002-01-01

    Physicists working in Europe announced yesterday that they had passed through nature's looking glass and had created atoms made of antimatter, or antiatoms, opening up the possibility of experiments in a realm once reserved for science fiction writers (5 pages)

  12. Will NASA annihilate station antimatter experiment?

    CERN Multimedia

    Lawler, A

    2004-01-01

    "NASA is reconsidering its support for an innovative experiment designed to capture direct evidence of elusive antimatter. [...] A full review of the project, called the Alpha Magnetic Spectrometer (AMS), could begin this summer" (1 page)

  13. Matter-antimatter puzzle: LHCb improves resolution

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In 2010, Fermilab’s DØ experiment reported a one percent difference in the properties of matter and antimatter in decays of B mesons (that is, particles containing beauty quarks) to muons. Saturday, at the ICHEP Conference in Melbourne, the LHCb experiment at CERN presents new results, which do not confirm this anomaly and are consistent with the Standard Model predictions. The same experiment has also presented the first evidence of asymmetry arising in other decays of the same family of mesons. The image becomes clearer but the puzzle has not yet been solved.   Inside the LHCb detector. The matter-antimatter imbalance in the Universe is a very hot topic in physics. The conundrum arises from the fact that, although objects made of antimatter are not observed in the Universe, theory predicts that matter and antimatter be created equally in particle interactions and in the Big Bang. Only small deviations from this very symmetric behaviour are incorporated in the theory. E...

  14. Observation of the antimatter helium-4 nucleus.

    Science.gov (United States)

    2011-05-19

    High-energy nuclear collisions create an energy density similar to that of the Universe microseconds after the Big Bang; in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quickly from matter, and avoid annihilation. Thus, a high-energy accelerator of heavy nuclei provides an efficient means of producing and studying antimatter. The antimatter helium-4 nucleus (4He), also known as the anti-α (α), consists of two antiprotons and two antineutrons (baryon number B = -4). It has not been observed previously, although the α-particle was identified a century ago by Rutherford and is present in cosmic radiation at the ten per cent level. Antimatter nuclei with B Collider (RHIC; ref. 6) in 10(9) recorded gold-on-gold (Au+Au) collisions at centre-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon pair. The yield is consistent with expectations from thermodynamic and coalescent nucleosynthesis models, providing an indication of the production rate of even heavier antimatter nuclei and a benchmark for possible future observations of 4He in cosmic radiation.

  15. Studying antimatter with laser precision

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    The next generation of antihydrogen trapping devices, ALPHA-2, is moving into CERN’s Antiproton Decelerator (AD) hall. This brand-new experiment will allow the ALPHA collaboration to conduct studies of antimatter with greater precision. ALPHA spokesperson Jeffrey Hangst was recently awarded a grant by the Carlsberg Foundation, which will be used to purchase equipment for the new experiment.   A 3-D view of the new magnet (in blue) and cryostat. The red lines show the paths of laser beams. LHC-type current leads for the superconducting magnets are visible on the top-right of the image. The ALPHA collaboration has been working to trap and study antihydrogen since 2006. Using antiprotons provided by CERN’s Antiproton Decelerator (AD), ALPHA was the first experiment to trap antihydrogen and to hold it long enough to study its properties. “The new ALPHA-2 experiment will use integrated lasers to probe the trapped antihydrogen,” explains Jeffrey Hangst, ALP...

  16. Antimatter, clockwork orange, laser divestment

    Science.gov (United States)

    Asmus, John F.

    2005-06-01

    In 1972 Ente Nazionale Idrocarburi sponsored a program to holographically record the images of Venetian sculptural treasures for archival purposes. At Laboratorio San Gregorio, where the initial holography took place, G. Musumeci and K. Hempel suggested an experiment to determine whether the concentrated beam from the ruby holographic laser could ablate black-patina crusts from decaying marble. Initial success of a laser-divestment test on a Palazzo Ducale capital launched a search for funding to enable a full-scale laser-conservation demonstration. Later, at a Caltech reunion one of the author's physics professors (Carl Anderson, the discoverer of mu mesons and the positron), noting the prominence of the Venice Film Festival suggested our approaching the motion picture industry. Many years earlier Anderson's Caltech classmate, Frank Capra, had supported the research that led to the discovery of cosmic-ray-generated antimatter on Pikes Peak. (After Caltech, Capra had become a director at Columbia Studios.) Anderson's chance comment led to an introduction to producer Jack Warner at a festival screening of his "A Clockwork Orange" in Asolo. He and his friends contributed US$5000 toward the laser conservation of a marble relief of "The Last Supper" in the Porta della Carta of Venice. This work was conducted in 1980 under the direction of Arch. G. Calcagno. In 1981 it was found that the granite veneer or the newly completed Warner Center Tower had been stained during transit from the quarry. The Venice laser successfully restored the veneer, thereby returning the Warner Brothers' favor.

  17. Antimatter annihilation detection with AEgIS

    CERN Document Server

    Gligorova, Angela

    2015-01-01

    AE ̄ gIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is an antimatter exper- iment based at CERN, whose primary goal is to carry out the first direct measurement of the Earth’s gravitational acceleration on antimatter. A precise measurement of antimatter gravity would be the first precision test of the Weak Equivalence Principle for antimatter. The principle of the experiment is based on the formation of antihydrogen through a charge exchange reaction between laser excited (Rydberg) positronium and ultra-cold antiprotons. The antihydrogen atoms will be accelerated by an inhomogeneous electric field (Stark acceleration) to form a pulsed cold beam. The free fall of the antihydrogen due to Earth’s gravity will be measured using a moiré de- flectometer and a hybrid position detector. This detector is foreseen to consist of an active silicon part, where the annihilation of antihydrogen takes place, followed by an emulsion part coupled to a fiber time-of-flight detector. This overview prese...

  18. Antimatter persuaded to react with matter

    CERN Multimedia

    Van Noorden, Richard

    2006-01-01

    "Matter and antimatter usually destroy each other in a flash of energy and a spray of exotic particles when they meet. Yet the two have been coaxed into a chemical reaction by the international research group Athena." (2/3 page)

  19. Does antimatter emit a new light?

    Energy Technology Data Exchange (ETDEWEB)

    Santilli, Ruggero Maria [Instituto per la Ricerca di Base (Italy)

    1997-08-15

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particles and antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus bypassing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of 'the new physics of antimatter' are pointed out.

  20. Antimatter and 20th Century Science

    Science.gov (United States)

    Williams, Gary

    2005-01-01

    This article gives an outline of the history of antimatter from the concept first introduced in 1898 up to the present day and is intended to complement the article "Antihydrogen on Tap" on page 229 [of this issue of "Physics Education"]. It is hoped that it will provide enough historical background material along with interesting snippets of…

  1. A moiré deflectometer for antimatter

    CERN Document Server

    Aghion, S; Amsler, C; Ariga, A; Ariga, T; Belov, A S; Berggren, K; Bonomi, G; Braunig, P; Bremer, J; Brusa, R S; Cabaret, L; Canali, C; Caravita, R; Castelli, F; Cerchiari, G; Cialdi, S; Comparat, D; Consolati, G; Derking, H; Di Domizio, S; Di Noto, L; Doser, M; Dudarev, A; Ereditato, A; Ferragut, R; Fontana, A; Genova, P; Giammarchi, M; Gligorova, A; Gninenko, S N; Haider, S; Huse, T; Jordan, E; Jørgensen, L V; Kaltenbacher, T; Kawada, J; Kellerbauer, A; Kimura, M; Knecht, A; Krasnicky, D; Lagomarsino, V; Lehner, S; Magnani, A; Malbrunot, C; Mariazzi, S; Matveev, V A; Moia, F; Nebbia, G; Nedelec, P; Oberthaler, M K; Pacifico, N; Petracek, V; Pistillo, C; Prelz, F; Prevedelli, M; Regenfus, C; Riccardi, C; Røhne, O; Rotondi, A; Sandaker, H; Scampoli, P; Storey, J; Subieta Vasquez, M A; Spacek, M; Testera, G; Vaccarone, R; Widmann, E; Zavatarelli, S; Zmeskal, J

    2014-01-01

    The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational inter- action is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics—the moire ́ deflectometer—for a measurement of the acceleration of slow antiprotons. The setup con- sists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleratio...

  2. Measuring gravitational effects on antimatter in space

    CERN Document Server

    Piacentino, Giovanni Maria; Venanzoni, Graziano

    2016-01-01

    We propose an experimental test of the gravitational interaction with antimatter by measuring the branching fraction of the CP~violating decay $K_\\mathrm{L} \\to \\pi^{+} \\pi^{-}$ in space. We show that at the altitude of the International Space Station, gravitational effects may change the level of CP~violation such that a 5$\\sigma$ discrimination may be obtained by collecting the $K_\\mathrm{L}$ produced by the cosmic proton flux within a few years.

  3. Measuring gravitational effects on antimatter in space

    Science.gov (United States)

    Piacentino, G. M.; Palladino, A.; Venanzoni, G.

    2016-09-01

    We propose an experimental test of the gravitational interaction with antimatter by measuring the branching fraction of the CP violating decay KL →π+π- in space. We show that at the altitude of the International Space Station, gravitational effects may change the level of CP violation such that a 5 σ discrimination may be obtained by collecting the KL produced by the cosmic proton flux within a few years.

  4. Gravitational mass of relativistic matter and antimatter

    CERN Document Server

    Kalaydzhyan, Tigran

    2015-01-01

    The universality of free fall, the so-called weak equivalence principle (WEP), is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial and gravitational masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no proof for the matter and antimatter at high energies. %coming from ground-based experiments. For the antimatter the situation is even less clear -- current direct observations of trapped antihydrogen suggest the limits -65 < m_g / m < 110 not ruling out antigravity, i.e. repulsion of the antimatter by Earth. Here we demonstrate a bound 1 - 4x10^{-7} < m_g/m < 1 + 2x10^{-7} on the gravitational mass of relativistic electrons and positrons in the potential of the Local Supercluster (LS) coming from the Large Electron-Positron Collider (LEP) and Tevatron accelerator experiments. By considering annual variations of the sol...

  5. Does antimatter emit a new light?

    Science.gov (United States)

    Santilli, Ruggero Maria

    1997-08-01

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particles and antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus bypassing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of “the new physics of antimatter” are pointed out.

  6. Gravitational mass of relativistic matter and antimatter

    Science.gov (United States)

    Kalaydzhyan, Tigran

    2015-12-01

    The universality of free fall, the weak equivalence principle (WEP), is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial, m, and gravitational, mg, masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no confirmation for the matter and antimatter at high energies. For the antimatter the situation is even less clear - current direct observations of trapped antihydrogen suggest the limits - 65 antigravity phenomenon, i.e. repulsion of the antimatter by Earth. Here we demonstrate an indirect bound 0.96 antigravity. By considering the absolute potential of the Local Supercluster (LS), we also predict the bounds 1 - 4 ×10-7

  7. Gravitational mass of relativistic matter and antimatter

    Directory of Open Access Journals (Sweden)

    Tigran Kalaydzhyan

    2015-12-01

    Full Text Available The universality of free fall, the weak equivalence principle (WEP, is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial, m, and gravitational, mg, masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no confirmation for the matter and antimatter at high energies. For the antimatter the situation is even less clear – current direct observations of trapped antihydrogen suggest the limits −65antimatter by Earth. Here we demonstrate an indirect bound 0.96

  8. CPT symmetry and antimatter gravity in general relativity

    CERN Document Server

    Villata, M

    2011-01-01

    The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on theoretical grounds. Starting from the CPT invariance of physical laws, we transform matter into antimatter in the equations of both electrodynamics and gravitation. In the former case, the result is the well-known change of sign of the electric charge. In the latter, we find that the gravitational interaction between matter and antimatter is a mutual repulsion, i.e. antigravity appears as a prediction of general relativity when CPT is applied. This result supports cosmological models attempting to explain the Universe accelerated expansion in terms of a matter-antimatter repulsive interaction.

  9. CPT symmetry and antimatter gravity in general relativity

    Science.gov (United States)

    Villata, M.

    2011-04-01

    The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on theoretical grounds. Starting from the CPT invariance of physical laws, we transform matter into antimatter in the equations of both electrodynamics and gravitation. In the former case, the result is the well-known change of sign of the electric charge. In the latter, we find that the gravitational interaction between matter and antimatter is a mutual repulsion, i.e. antigravity appears as a prediction of general relativity when CPT is applied. This result supports cosmological models attempting to explain the Universe accelerated expansion in terms of a matter-antimatter repulsive interaction.

  10. Antimatter: What is and where did it go?

    International Nuclear Information System (INIS)

    In this public lecture we will explore the mystery of antimatter: Where did it go? Why is the universe made up of only matter, with no observable antimatter? And why does the universe have any matter left in it anyway? The SLAC 'B'-Factory was built to answer these questions. Over the last decade, almost a billion 'B'-mesons were created and studied at the B-Factory to search for subtle differences between matter and antimatter, differences that lie at the heart of the antimatter mystery. We will explain the matter-antimatter discoveries made at the B-Factory, and their connection to this year's Nobel prize in physics. It does not matter if you have no prior knowledge of Antimatter; just bring your curiosity.

  11. Hangout With CERN: Antimatter (S01E05)

    CERN Multimedia

    Kahle, Kate

    2012-01-01

    In this hangout we delve into the world of antimatter. How is it different from matter? What antimatter research is going on at CERN? Why? What have we learned so far and what will this research lead to? ATLAS physicist Steven Goldfarb is joined by CERN theorist Alex Arbey, Seth Zenz from the CMS experiment, and Michael Doser, Makoto Fujiwara and Masaki Hori from the antimatter experiments at CERN.Recorded live on 29th November 2012.

  12. Antimatter. (Latest citations from the INSPEC database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    The bibliography contains citations concerning physical theory, testing, and practical applications of antimatter. Related nuclear phenomena, matter-antimatter interactions, relativity, antigravity, formation of the universe, and space-time configurations are described. The roles of cosmic rays, black holes, antiprotons, and positrons are discussed. Antimatter propulsion spacecraft are briefly cited. (Contains a minimum of 182 citations and includes a subject term index and title list.)

  13. Antimatter. (Latest citations from the INSPEC database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    The bibliography contains citations concerning physical theory, testing, and practical applications of antimatter. Related nuclear phenomena, matter-antimatter interactions, relativity, antigravity, formation of the universe, and space-time configurations are described. The roles of cosmic rays, black holes, antiprotons, and positrons are discussed. Antimatter propulsion spacecraft are briefly cited. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  14. Experiments with low-energy antimatter

    Directory of Open Access Journals (Sweden)

    Consolati G.

    2015-01-01

    Full Text Available Investigations on antimatter allow us to shed light on fundamental issues of contemporary physics. The only antiatom presently available, antihydrogen, is produced making use of the Antiproton Decelerator (AD facility at CERN. International collaborations currently on the floor (ALPHA, ASACUSA and ATRAP have succeeded in producing antihydrogen and are now involved in its confinement and manipulation. The AEGIS experiment is currently completing the commissioning of the apparatus which will generate and manipulate antiatoms. The present paper, after a report on the main results achieved with antihydrogen physics, gives an overview of the AEGIS experiment, describes its current status and discusses its first target.

  15. Black Holes and Gravitational Properties of Antimatter

    CERN Document Server

    Hajdukovic, D

    2006-01-01

    We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.

  16. Hints of Greater Matter - Antimatter Asymmetry Challenge Theorists

    CERN Multimedia

    Cho, Adrian

    2010-01-01

    "The universe is chock-full of matter and devoid of antimatter, and physicists can't say why. They think that matter piled up after the big bang thanks to a slight asymmetry, called charge-parity (CP) violation, in the way matter and antimatter behave, but the effects seen so far are too small to do the job" (1 page)

  17. Feasibility for EGRET detection of antimatter concentrations in the universe

    Science.gov (United States)

    Hartman, R. C.

    1990-01-01

    Although the Grand Unified Theories of elementary particle dynamics have to some extent reduced the aesthetic attraction of matter-antimatter symmetry in the Universe, the idea is still not ruled out. Although first introduced by Alfven (1965), most of the theoretical development related to gamma-ray astronomy was carried out by Stecker, who has proposed (Stecker, Morgan, and Bredekamp, 1971) matter-antimatter annihilation extending back to large redshifts as a possible explanation of the apparently extragalactic diffuse gamma radiation. Other candidate explanations were also proposed, such as superposition of extragalactic discrete sources. Clearly, the existence of significant amounts of antimatter in the universe would be of great cosmological importance; its detection, however, is not simple. Since the photon is its own antiparticle, it carries no signature identifying whether it originated in a matter or an antimatter process; even aggregates of photons (spectra) are expected to be identical from matter and antimatter processes. The only likely indicator of the presence of concentrations of antimatter is evidence of its annihilation with normal matter, assuming there is some region of contact or overlap. The EGRET (Energetic Gamma-Ray Experimental Telescope) on the Gamma Ray Observatory, with a substantial increase in sensitivity compared with earlier high energy gamma ray telescopes, may be able to address this issue. The feasibility of using EGRET in such a search for antimatter annihilation in the Universe is considered.

  18. Detection of low energy antimatter with emulsions

    CERN Document Server

    Aghion, S; Ariga, T; Bollani, M; Cas, E Dei; Ereditato, A; Evans, C; Ferragut, R; Giammarchi, M; Pistillo, C; Romé, M; Sala, S; Scampoli, P

    2016-01-01

    Emulsion detectors feature a very high position resolution and consequently represent an ideal device when particle detection is required at the micrometric scale. This is the case of quantum interferometry studies with antimatter, where micrometric fringes have to be measured. In this framework, we designed and realized a new emulsion based detector characterized by a gel enriched in terms of silver bromide crystal contents poured on a glass plate. We tested the sensitivity of such a detector to low energy positrons in the range 10-20 keV. The obtained results prove that nuclear emulsions are highly efficient at detecting positrons at these energies. This achievement paves the way to perform matter-wave interferometry with positrons using this technology.

  19. Where has all the antimatter gone? VELO seeks the answer

    CERN Multimedia

    Ormrod, Gill

    2007-01-01

    "Scientists from the Universities of Liverpool and Glasgow have completed work on the inner heart of an experiment which seeks to find out what has happened to all the antimatter created at the start of the Universe." (2 pages)

  20. Cosmological matter-antimatter asymmetry as a quantum fluctuation

    CERN Document Server

    Kobakhidze, Archil

    2015-01-01

    We entertain a new paradigm according to which the observed matter-antimatter asymmetry is generated as a large-scale quantum fluctuation over the baryon-symmetric state that occurred during the cosmic inflation.

  1. Elusive antimatter formed in laboratory scientists testing nature's deepest secrets

    CERN Multimedia

    Boyd, R S

    2002-01-01

    A team of European physicists reported the creation in a Swiss laboratory of at least 50,000 atoms of antihydrogen, the first time a significant quantity of antimatter has been produced on earth (1 page).

  2. The matter-antimatter interpretation of Kerr spacetime

    CERN Document Server

    Villata, M

    2014-01-01

    Repulsive gravity is not very popular in physics. However, one comes across it in at least two main occurrences in general relativity: in the negative-$r$ region of Kerr spacetime, and as the result of the gravitational interaction between matter and antimatter, when the latter is assumed to be CPT-transformed matter. Here we show how these two independent developments of general relativity are perfectly consistent in predicting gravitational repulsion and how the above Kerr negative-$r$ region can be interpreted as the habitat of antimatter. As a consequence, matter particles traveling along vortical geodesics can pass through the throat of a rotating black hole and emerge as antimatter particles (and vice versa). An experimental definitive answer on the gravitational behavior of antimatter is awaited in the next few years.

  3. 2nd International Workshop on Antimatter and Gravity

    CERN Document Server

    Scampoli, P

    2013-01-01

    The purpose of this meeting is to review the experimental and theoretical aspects of the interaction of antimatter with gravity. Tests of the weak equivalence principle with e.g. positronium, muonium and antihydrogen with be discussed. Progress reports on the experiments at the CERN Antiproton Decelerator and on the available future facilities will be presented. A session on the relevance of antimatter with respect to Dark Energy and Dark Matter in the Universe (theory and experiments) is also foreseen.

  4. Antimatter in the Direct-Action Theory of Fields

    CERN Document Server

    Kastner, R E

    2015-01-01

    One of Feynman's greatest contributions to physics was the interpretation of negative energies as antimatter in quantum field theory. A key component of this interpretation is the Feynman propagator, which seeks to describe the behavior of antimatter at the virtual particle level. Ironically, it turns out that one can dispense with the Feynman propagator in a direct-action theory of fields, while still retaining the interpretation of negative energy solutions as antiparticles.

  5. Direct observation limits on antimatter gravitation

    Energy Technology Data Exchange (ETDEWEB)

    Fischler, Mark; Lykken, Joe; Roberts, Tom; /Fermilab

    2008-06-01

    The proposed Antihydrogen Gravity experiment at Fermilab (P981) will directly measure the gravitational attraction g between antihydrogen and the Earth, with an accuracy of 1% or better. The following key question has been asked by the PAC: Is a possible 1% difference between g and g already ruled out by other evidence? This memo presents the key points of existing evidence, to answer whether such a difference is ruled out (a) on the basis of direct observational evidence; and/or (b) on the basis of indirect evidence, combined with reasoning based on strongly held theoretical assumptions. The bottom line is that there are no direct observations or measurements of gravitational asymmetry which address the antimatter sector. There is evidence which by indirect reasoning can be taken to rule out such a difference, but the analysis needed to draw that conclusion rests on models and assumptions which are in question for other reasons and are thus worth testing. There is no compelling evidence or theoretical reason to rule out such a difference at the 1% level.

  6. Academic Training - Studying Anti-Matter

    CERN Multimedia

    Françoise Benz

    2006-01-01

    ACADEMIC TRAINING LECTURE SERIES 24, 25, 26 April from 11:00 to 12:00 - Main Auditorium, bldg. 500 Main Auditorium, bldg. 500 on 14, 15 March, Council Room on 13, 16 March Studying Anti-Matter R. LANDUA / DSU Antiparticles are a crucial ingredient of particle physics and cosmology. Almost 80 years after Dirac's bold prediction and the subsequent discovery of the positron in 1932, antiparticles are still in the spotlight of modern physics. This lecture for non-specialists will start with a theoretical and historical introduction. Why are antiparticles needed? When and how were they discovered? Why is the (CPT) symmetry between particles and antiparticles so fundamental? What is their role in cosmology? The second part will give an overview about the many aspects of antiparticles in experimental physics: their production, their use in colliders; as a probe inside atoms or nuclei; or as an object to study fundamental symmetries. In the third part, the lecture will focus on results and challenges of the '...

  7. The antimatter factory is ready for another successful year

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    CERN’s contribution to antimatter research is interspersed with important breakthroughs: from the creation of the very first anti-atoms in 1995 to the production of large quantities in 2002 and the invention in 2010 of the technique that freezes them down to allow precise studies of their properties. This week, antimatter experiments are on the starting blocks for a new run that promises to be just as exciting.   The Antiproton Decelerator (AD). CERN’s Antimatter Decelerator (AD) is a unique antimatter factory that produces low-energy anti-protons for creating anti-atoms. The AD delivers its precious ingredients to several experiments that use them to study antimatter properties from many different angles. The 2011 run is about to start, and the experiments are ready to enter a new data-taking period. Their scientific goals for this year include applying spectroscopy techniques for the first time to probe the inner workings of antihydrogen atoms; evaluating the biological effe...

  8. Proposed antimatter gravity measurement with an antihydrogen beam

    CERN Document Server

    Kellerbauer, A G

    2008-01-01

    The principle of the equivalence of gravitational and inertial mass is one of the cornerstones of general relativity. Considerable efforts have been made and are still being made to verify its validity. A quantum-mechanical formulation of gravity allows for non-Newtonian contributions to the force which might lead to a difference in the gravitational force on matter and antimatter. While it is widely expected that the gravitational interaction of matter and of antimatter should be identical, this assertion has never been tested experimentally. With the production of large amounts of cold antihydrogen at the CERN Antiproton Decelerator, such a test with neutral antimatter atoms has now become feasible. For this purpose, we have proposed to set up the AEGIS experiment at CERN/AD, whose primary goal will be the direct measurement of the Earth’s gravitational acceleration on antihydrogen with a classical Moiré deflectometer.

  9. Polarization of photons in matter–antimatter annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Moskaliuk, S.S. [Bogolyubov Institute for Theoretical Physics, Metrolohichna Street, 14-b, Kyiv-143, Ukraine, UA-03143 e-mail: mss@bitp.kiev.ua (Ukraine)

    2015-03-10

    In this work we demonstrate the possibility of generation of linear polarization of the electromagnetic field (EMF) due to the quantum effects in matter-antimatter annihilation process for anisotropic space of the I type according to Bianchi. We study the dynamics of this process to estimate the degree of polarisation of the EMF in the external gravitational field of the anisotropic Bianchi I model. It has been established that the quantum effects in matter-antimatter annihilation process in the external gravitational field of the anisotropic Bianchi I model provide contribution to the degree of polarisation of the EMF in quadrupole harmonics.

  10. On the random geometry of a symmetric matter antimatter universe

    International Nuclear Information System (INIS)

    A statistical analysis is made of the randon geometry of an early symmetric matter-antimatter universe model. Such a model is shown to determine the total number of the largest agglomerations in the universe, as well as of some special configurations. Constraints on the time development of the protoagglomerations are also obtained

  11. The Role of Antimatter in Big-Bang Cosmology

    Science.gov (United States)

    Stecker, Floyd W.

    1974-01-01

    Discusses theories underlying man's conceptions of the universe, including Omnes' repulsive separation mechanism, the turbulence theory of galaxy formation, and the author's idea about gamma ray spectra in cosmological matter-antimatter annihilation. Indicates that the Apollo data provide encouraging evidence by fitting well with his theoretical…

  12. Antimatter Assisted Inertial Confinement Fusion Propulsion Systems for Interstellar Missions

    Science.gov (United States)

    Halyard, R. J.

    Current developments such as the Ion Compressed Antimatter Nuclear (ICAN-II) propulsion system proposed by the Pennsylvania State University Center for Space Propulsion Engineering open the way to the possible use of available supplies of antiprotons to power antimatter assisted inertial confinement fusion (AAICF) propulsion systems for interstellar missions. Analysis indicates that light weight AAICF propulsion systems with specific impulses in excess of seven hundred thousand seconds may be feasible within the next 30 years. AAICF should prove to be the optimum propulsion system since it possesses high thrust, low weight and high exhaust velocity. The purpose of this paper is to evaluate the potential of AAICF propulsion for interstellar missions such as NASA Administrator Dan Goldin's Alpha Centauri Flyby and a Barnard's Star Orbital Mission, and to compare these projections with previous performance estimates for ICF Laser Beam propulsion systems.

  13. ELENA prepares a bright future for antimatter research

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    At its recent session in June, the CERN Council approved the construction of the Extra Low ENergy Antiproton ring (ELENA) – an upgrade of the existing Antiproton Decelerator. ELENA will allow the further deceleration of antiprotons, resulting in an increased number of particles trapped downstream in the experimental set-ups. This will give an important boost to antimatter research in the years to come.   Layout of the AD experimental hall: the Antiproton Decelerator ring (purple); the ALPHA, ASACUSA, and ATRAP experiments (green); the ACE experiment (not pictured); and the new ELENA ring (blue). The Antiproton Decelerator (AD) is CERN’s widely recognized facility for the study of antimatter properties. The recent successes of the AD experiments are just the latest in a long list of important scientific results that started with LEAR (Low Energy Antiproton Ring). The scientific demand for low-energy antiprotons at the AD continues to grow. There are now four experiments runnin...

  14. ALICE’s wonderland reveals the heaviest antimatter ever observed

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Producing and observing antiparticles is part of everyday life for many physics laboratories around the world, including CERN. However, recreating and observing the anti-nuclei of complex atoms is a much more difficult task. Analysing data collected in a run of just one month, ALICE has recently found evidence of the formation of four anti-nuclei of Helium 4, the heaviest antimatter ever created in a laboratory.   The STAR experiment at RHIC came first and published the result in March: they presented evidence of 18 anti-nuclei of Helium 4 collected over several years of data taking. “ALICE came second but it's amazing to see how fast the results came,” exclaims Paolo Giubellino, the experiment’s spokesperson. “We were able to confirm the observation of 4He anti-nuclei with data collected in November 2010.” Scientists agree on the fact that antimatter was created in the Big Bang together with matter. However, today we do not observe antimatter outsid...

  15. Matter-Antimatter Asymmetry in the Large Hadron Collider

    CERN Document Server

    Tawfik, A

    2010-01-01

    The matter-antimatter asymmetry is one of the greatest challenges in the modern physics. The universe including this paper and even the reader him(her)self seems to be built up of ordinary matter only. Theoretically, the well-known Sakharov's conditions remain the solid framework explaining the circumstances that matter became dominant against the antimatter while the universe cools down and/or expands. On the other hand, the standard model for elementary particles apparently prevents at least two conditions out of them. In this work, we introduce a systematic study of the antiparticle-to-particle ratios measured in various $NN$ and $AA$ collisions over the last three decades. It is obvious that the available experimental facilities turn to be able to perform nuclear collisions, in which the matter-antimatter asymmetry raises from $\\sim 0%$ at AGS to $\\sim 100%$ at LHC. Assuming that the final state of hadronization in the nuclear collisions takes place along the freezeout line, which is defined by a constant...

  16. The generation model of particle physics and the cosmological matter-antimatter asymmetry problem

    CERN Document Server

    Robson, B A

    2016-01-01

    The matter-antimatter asymmetry problem, corresponding to the virtual nonexistence of antimatter in the universe, is one of the greatest mysteries of cosmology. Within the framework of the Generation Model (GM) of particle physics, it is demonstrated that the matter-antimatter asymmetry problem may be understood in terms of the composite leptons and quarks of the GM. It is concluded that there is essentially no matter-antimatter asymmetry in the present universe and that the observed hydrogen-antihydrogen asymmetry may be understood in terms of statistical fluctuations associated with the complex many-body processes involved in the formation of either a hydrogen atom or an antihydrogen atom.

  17. Neutrinos and the matter-antimatter asymmetry in the Universe

    CERN Document Server

    Felipe, R Gonzalez

    2011-01-01

    The discovery of neutrino oscillations provides a solid evidence for nonzero neutrino masses and leptonic mixing. The fact that neutrino masses are so tiny constitutes a puzzling problem in particle physics. From the theoretical viewpoint, the smallness of neutrino masses can be elegantly explained through the seesaw mechanism. Another challenging issue for particle physics and cosmology is the explanation of the matter-antimatter asymmetry observed in Nature. Among the viable mechanisms, leptogenesis is a simple and well-motivated framework. In this talk we briefly review these aspects, making emphasis on the possibility of linking neutrino physics to the cosmological baryon asymmetry originated from leptogenesis.

  18. Hangout with CERN and the Google Science Fair: Why does antimatter matter? (S03E01)

    CERN Multimedia

    Kahle, Kate

    2013-01-01

    What is antimatter? Why does antimatter matter? Series 3 of Hangout with CERN starts with a bang! A special hangout with CERN and the Google Science Fair that takes us into the weird and wonderful world of antimatter.CERN physicists Tara Shears and Niels Madsen speak to host Shree Bose, Google Science Fair 2011 grand prize winner and to Samantha Lee, Google Student Ambassador, about this mysterious part of our universe. What antimatter research is going on at CERN and what are the implications? CERN's Rolf Landua also shows us the Hollywood-side of antimatter!Google Science Fair is an online science competition open to students aged 13-18 from around the globe. Students can register at googlesciencefair.com, the closing date is 30 April 2013. Find out more about CERN's involvement in Google Science Fair at http://goo.gl/N9f3GRecorded live on 18th April 2013.

  19. A new “culprit” for matter-antimatter asymmetry

    CERN Multimedia

    Antonella Del Rosso

    2013-01-01

    In our matter-dominated Universe, the observation of new processes showing matter-antimatter asymmetry allows scientists to test their theories and, possibly, to explore new territories. The LHCb collaboration has recently observed matter-antimatter asymmetries in the decays of the B0s meson, which thus becomes the fourth particle known to present such behaviour.   The VELO detector: a crucial element for particle identifiation in LHCb. Almost all physics processes known to scientists show perfect symmetry if a particle is interchanged with its antiparticle (C symmetry), and then if left and right are swapped (P symmetry). So it becomes very hard to explain why the Universe itself does not conform to this symmetry and, instead, shows a huge preference for matter. Processes that violate this symmetry are rare and of great interest to scientists. Violation of the CP symmetry in neutral kaons was first observed by Nobel Prize Laureates James Cronin and Val Fitch in the 1960s. About 40 years la...

  20. Matter-antimatter asymmetry and dark matter from torsion

    Science.gov (United States)

    Popławski, Nikodem J.

    2011-04-01

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. Spacetime torsion produced by spin generates, in the classical Dirac equation, the Hehl-Datta term which is cubic in spinor fields. We show that under a charge-conjugation transformation this term changes sign relative to the mass term. A classical Dirac spinor and its charge conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly to hidden antimatter which forms dark matter. The conserved total baryon number of the Universe remained zero.

  1. Do we live in the universe successively dominated by matter and antimatter?

    CERN Document Server

    Hajdukovic, Dragan Slavkov

    2011-01-01

    We wonder if a cyclic universe may be dominated alternatively by matter and antimatter. Such a scenario demands a mechanism for transformation of matter to antimatter (or antimatter to matter) during the final stage of a big crunch. By giving an example, we have shown that in principle such a mechanism is possible. Our mechanism is based on a hypothetical repulsion between matter and antimatter, existing at least deep inside the horizon of a black hole. When universe is reduced to a supermassive black hole of a small size, a very strong field of the conjectured force might create (through a Schwinger type mechanism) particle-antiparticle pairs from the quantum vacuum. The amount of antimatter created from the vacuum is equal to the decrease of mass of the black hole and violently repelled from it. When the size of the black hole is sufficiently small, the creation of antimatter may become so fast, that matter of our Universe might be transformed to antimatter in a fraction of second. Such a fast conversion of...

  2. From d-Bars to Antimatter- and Hyperclusters

    Science.gov (United States)

    Steinheimer, J.; Xu, Zhangbu; Rau, P.; Sturm, C.; Stöcker, H.

    The Facility for Antiproton and Ion Research (FAIR) is going to be constructed within the next six years adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt/Germany, expanding the research goals and technical possibilities substantially. Providing a broad spectrum of unprecedented fore-front research at worldwide unique accelerator and experimental facilities, FAIR will open the way for a large variety of experiments in hadron, nuclear, atomic and plasma physics as well as applied sciences which will be briefly described in this article. As an example the article presents research efforts on strangeness at FAIR using heavy ion collisions, exotic nuclei from fragmentation and antiprotons to tackle various topics in this area. In particular the creation of hypernuclei as well as metastable exotic multi-hypernuclear objects (MEMOs) and anti-matter will be investigated.

  3. Isodual theory of antimatter applications to antigravity, grand unification and cosmology

    CERN Document Server

    Santilli, Ruggero Maria

    2006-01-01

    Antimatter, already conjectured by A. Schuster in 1898, was actually predicted by P.A.M. Dirac in the late 19-twenties in the negative-energy solutions of the Dirac equation. Its existence was subsequently confirmed via the Wilson chamber and became an established part of theoretical physics. Dirac soon discovered that particles with negative energy do not behave in a physically conventional manner, and he therefore developed his "hole theory". This restricted the study of antimatter to the sole level of second quantization. As a result antimatter created a scientific imbalance, because matter was treated at all levels of study, while antimatter was treated only at the level of second quantization. In search of a new mathematics for the resolution of this imbalance the author conceived what we know today as Santilli’s isodual mathematics, which permitted the construction of isodual classical mechanics, isodual quantization and isodual quantum mechanics. The scope of this monograph is to show that our classi...

  4. Santilli’s detection of antimatter galaxies: An introduction and experimental confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Bhujbal, P. M. [Department of Physics, Nutan Adarsh Arts, Commerce and Smt. Maniben Harilal Wegad Science College, Umrer-441203, India. Email: prashantmbhujbal@yahoo.com (India)

    2015-03-10

    Studies accompanied over the past few decades on the generalization of quantum mechanics known as hadronic mechanics, initiated in 1978 by the Italian-American physicist Ruggero Maria Santilli and its application for detection of light from antimatter galaxy is reported in this paper. The isodual (antimatter) light has negative energy E{sup d} =-E with negative unit, experiences a negative curvature tensor R{sup d}=-R (gravitational repulsion) when in a matter gravitational field, and possesses a negative index of refraction n{sup d}=-n when propagating within a transparent matter medium. Detection of antimatter galaxies is possible by the refractive telescope with concave lenses constructed by Santilli which follow the concept of negative energy and negative index of refraction for antimatter.

  5. A trip to Rome—thanks to antimatter

    CERN Multimedia

    Alizée Dauvergne

    2010-01-01

    The Angels and Demons exhibition created by the PH Department’s Education Group came to an end last summer. The exhibition was accompanied by a competition, with a first prize of a flight to Rome. Now we know the winner’s name. An exhibit of the Angels&Demons - the science behind the story exhibition She is Sarah Manton, and she is from Scotland. In September Sarah will fly to Rome with her husband to retrace the Angels and Demons street itinerary. “We are looking forward to visiting the usual tourist sights, including all the places that feature in Angels and Demons such as the Pantheon,” she said in answer to a question from the exhibition organisers. The couple was touring CERN when, intrigued by the Globe and the name of the exhibition, they decided to do a visit and participate in the competition. Five correct answers on antimatter later—and several months on—Sarah got a pleasant surprise: “I decided to have a go at the quiz an...

  6. LS1 Report: antimatter research on the starting blocks

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The consolidation work at the Antiproton Decelerator (AD) has been very intensive and the operators now have a basically new machine to “drive”. Thanks to the accurate preparation work still ongoing, the machine will soon deliver its first beam of antiprotons to the experiments. The renewed efficiency of the whole complex will ensure the best performance of the whole of CERN’s antimatter research programme in the long term.   The test bench for the new Magnetic Horn stripline. On the left, high voltage cables are connected to the stripline, which then feeds a 6 kV 400 kA pulse to the Horn. The Horn itself (the cylindrical object on the right) can be seen mounted on its chariot. The consolidation programme at the AD planned during LS1 has involved some of the most vital parts of the decelerator such as the target area, the ring magnets, the stochastic cooling system, vacuum system, control system and various aspects of the instrumentation. In addit...

  7. Measurement of matter-antimatter differences in beauty baryon decays

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Archilli, Flavio; d'Argent, Philippe; Arnau Romeu, Joan; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Babuschkin, Igor; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Baszczyk, Mateusz; Batozskaya, Varvara; Batsukh, Baasansuren; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bezshyiko, Iaroslava; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bitadze, Alexander; Bizzeti, Andrea; Blake, Thomas; Blanc, Frederic; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Boettcher, Thomas; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Bossu, Francesco; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Camboni, Alessandro; Campana, Pierluigi; Campora Perez, Daniel; Campora Perez, Daniel Hugo; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; 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Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fleuret, Frederic; Fohl, Klaus; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Franco Lima, Vinicius; Frank, Markus; Frei, Christoph; Fu, Jinlin; Furfaro, Emiliano; Färber, Christian; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; Garcia Martin, Luis Miguel; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Garsed, Philip John; Gascon, David; Gaspar, Clara; Gavardi, Laura; Gazzoni, Giulio; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gizdov, Konstantin; Gligorov, Vladimir; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gorelov, Igor Vladimirovich; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Griffith, Peter; Grillo, Lucia; Gruberg Cazon, Barak Raimond; Grünberg, Oliver; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Göbel, Carla; Hadavizadeh, Thomas; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; Hatch, Mark; He, Jibo; Head, Timothy; Heister, Arno; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hombach, Christoph; Hopchev, P H; Hulsbergen, Wouter; Humair, Thibaud; Hushchyn, Mikhail; Hussain, Nazim; Hutchcroft, David; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jiang, Feng; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Kariuki, James Mwangi; Karodia, Sarah; 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Loh, David; Longstaff, Iain; Lopes, Jose; Lucchesi, Donatella; Lucio Martinez, Miriam; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Lusiani, Alberto; Lyu, Xiao-Rui; Machefert, Frederic; Maciuc, Florin; Maev, Oleg; Maguire, Kevin; Malde, Sneha; Malinin, Alexander; Maltsev, Timofei; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Marks, Jörg; Martellotti, Giuseppe; Martin, Morgan; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massacrier, Laure Marie; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; Meadows, Brian; Meier, Frank; Meissner, Marco; Melnychuk, Dmytro; Merk, Marcel; Merli, Andrea; Michielin, Emanuele; Milanes, Diego Alejandro; Minard, Marie-Noelle; Mitzel, Dominik Stefan; 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dos Reis, Alberto; Remon Alepuz, Clara; Renaudin, Victor; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vicente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Rogozhnikov, Alexey; Roiser, Stefan; Romanovskiy, Vladimir; Romero Vidal, Antonio; Ronayne, John William; Rotondo, Marcello; Rudolph, Matthew Scott; Ruf, Thomas; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sadykhov, Elnur; Sagidova, Naylya; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schael, Stefan; Schellenberg, Margarete; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubert, Konstantin; 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    2016-01-01

    Differences in the behaviour of matter and antimatter have been observed in $K$ and $B$ meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as CP violation. Using data from the LHCb experiment at the Large Hadron Collider, a search is made for CP-violating asymmetries in the decay angle distributions of $\\Lambda_b^0$ baryons decaying to $p\\pi^-\\pi^+\\pi^-$ and $p \\pi^- K^+ K^-$ final states. These four-body hadronic decays are a promising place to search for sources of CP violation both within and beyond the Standard Model of particle physics. We find evidence for CP violation in $\\Lambda_b^0$ to $p\\pi^-\\pi^+\\pi^-$ decays with a statistical significance corresponding to 3.3 standard deviations including systematic uncertainties. This represents the first evidence for CP violation in the baryon sector.

  8. Mean-field effects on matter and antimatter elliptic flow

    International Nuclear Information System (INIS)

    We report our recent work on mean-field potential effects on the elliptic flows of matters and antimatters in heavy ion collisions leading to the production of a baryon-rich matter. Within the framework of a multiphase transport (AMPT) model that includes both initial partonic and final hadronic interactions, we have found that including mean-field potentials in the hadronic phase leads to a splitting of the elliptic flows of particles and their antiparticles, providing thus a plausible explanation of the different elliptic flows between p and anti-p, K+ and K-, and π+ and π- observed by the STAR Collaboration in the Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC). Using a partonic transport model based on the Nambu-Jona-Lasinio (NJL) model, we have also studied the effect of scalar and vector mean fields on the elliptic flows of quarks and antiquarks in these collisions. Converting quarks and antiquarks at hadronization to hadrons via the quark coalescence model, we have found that the elliptic flow differences between particles and antiparticles also depend on the strength of the quark vector coupling in baryon-rich quark-gluon plasma, providing thus the possibility of extracting information on the latter's properties from the BES program at RHIC. (authors)

  9. New experiment to gain unparalleled insight into antimatter

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    At last week’s Research Board meeting, the Baryon Antibaryon Symmetry Experiment (BASE) was approved for installation at CERN. The experiment will be diving into the search for matter-antimatter asymmetry, as it aims to take ultra-high precision measurements of the antiproton magnetic moment.   CERN's AD Hall: the new home of the BASE double Penning trap set-up. The BASE collaboration will be setting up shop in the AD Hall this September with its first CERN-based experimental set-up. Using the novel double-Penning trap set-up developed at the University of Mainz, GSI Darmstadt and the Max Plank Institute for Nuclear Physics (Germany), the BASE team will be able to measure the antiproton magnetic moment with hitherto unreachable part-per-billion precision. “We constructed the first double-Penning trap at our companion facility in Germany, and made the first ever direct observations of single spin flips of a single proton,” explains Stefan Ulmer from RIKE...

  10. Matter-antimatter asymmetry and dark matter from torsion

    CERN Document Server

    Poplawski, Nikodem J

    2011-01-01

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. The torsion of spacetime generates in the Dirac equation the Hehl-Datta term which is cubic in spinor fields. We show that under the charge-conjugation transformation this term changes sign relative to the mass term. A Dirac spinor and its charge-conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly ...

  11. a Classical Isodual Theory of Antimatter and its Prediction of Antigravity

    Science.gov (United States)

    Santilli, Ruggero Maria

    An inspection of the contemporary physics literature reveals that, while matter is treated at all levels of study, from Newtonian mechanics to quantum field theory, antimatter is solely treated at the level of second quantization. For the purpose of initiating the restoration of full equivalence in the treatment of matter and antimatter in due time, and as the classical foundations of an axiomatically consistent inclusion of gravitation in unified gauge theories recently appeared elsewhere, in this paper we present a classical representation of antimatter which begins at the primitive Newtonian level with corresponding formulations at all subsequent levels. By recalling that charge conjugation of particles into antiparticles is antiautomorphic, the proposed theory of antimatter is based on a new map, called isoduality, which is also antiautomorphic (and more generally, antiisomorphic), yet it is applicable beginning at the classical level and then persists at the quantum level where it becomes equivalent to charge conjugation. We therefore present, apparently for the first time, the classical isodual theory of antimatter, we identify the physical foundations of the theory as being the novel isodual Galilean, special and general relativities, and we show the compatibility of the theory with all available classical experimental data on antimatter. We identify the classical foundations of the prediction of antigravity for antimatter in the field of matter (or vice-versa) without any claim on its validity, and defer its resolution to specifically identified experiments. We identify the novel, classical, isodual electromagnetic waves which are predicted to be emitted by antimatter, the so-called space-time machine based on a novel non-Newtonian geometric propulsion, and other implications of the theory. We also introduce, apparently for the first time, the isodual space and time inversions and show that they are nontrivially different than the conventional ones, thus

  12. Beautiful asymmetry[The difference between matter and antimatter

    Energy Technology Data Exchange (ETDEWEB)

    Forty, R. [CERN (Switzerland)]. E-mail: roger.forty@cern.ch

    2006-10-15

    The LHCb experiment at CERN will allow researchers to study the difference between matter and antimatter with unprecedented accuracy, explains Roger Forty. Our current understanding of matter and forces at the subatomic scale, as embodied in the Standard Model of particle physics, is widely considered incomplete. Its most famous missing ingredient is the Higgs Boson, thought to endow all particles with mass, but there are strong indications that other pieces of the theoretical jigsaw puzzle are missing too. One of these concerns 'dark matter', the mysterious substance thought to make up more than a fifth of the universe. Postulated to account for gravitational effects that cannot be explained by the amount of visible matter alone, dark matter could be made up of exotic new particles that are not described by the Standard Model. Fortunately, there is a good chance that such particles - and the Higgs - will be created in the high-energy collisions between protons at the Large Hadron Collider (LHC). There are two approaches to discovering such new physics. The first is to try and observe the new particles directly by detecting their decay products, which will be the goal of the two giant 'general-purpose' LHC experiments ATLAS and CMS. The alternative approach is to make precision measurements of parameters that are predicted within the Standard Model and to look for deviations that could be due to as-yet-undetected particles. This is the goal of the LHCb (LHC beauty) experiment, which is dedicated to the precision study of particles that contain the bottom or beauty quark. (U.K.)

  13. Anti-cluster Decay and Anti-alpha Decay of Antimatter nuclei

    CERN Document Server

    Poenaru, D N; Greiner, W

    2015-01-01

    A broad extension of periodic system into the sector of antimatter could be possible sometimes in a remote future. We expect that anti-alpha spontaneous emission from an antimatter nucleus will have the same Q-value and half-life as alpha emission from the corresponding mirror nucleus. This is the consequence of the invariance of binding energy as well as of the surface and Coulomb energy when passing from matter to antimatter nuclei with the the same mass number and the same atomic number. The Q-values and half-lives of all measured up to now 27 cluster radioactivities are given together with Q-values and half-lives of the most important competitor --- $\\alpha$ decay. The lightest anti-alpha emitter, $^8\\bar{Be}$, will have a very short half-life of about $81.9\\cdot 10^{-18}$ s.

  14. A position sensitive silicon detector for AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy)

    CERN Multimedia

    Gligorova, A

    2014-01-01

    The AEḡIS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is located at the Antiproton Decelerator (AD) at CERN and studies antimatter. The main goal of the AEḡIS experiment is to carry out the first measurement of the gravitational acceleration for antimatter in Earth’s gravitational field to a 1% relative precision. Such a measurement would test the Weak Equivalence Principle (WEP) of Einstein’s General Relativity. The gravitational acceleration for antihydrogen will be determined using a set of gravity measurement gratings (Moiré deflectometer) and a position sensitive detector. The vertical shift due to gravity of the falling antihydrogen atoms will be detected with a silicon strip detector, where the annihilation of antihydrogen will take place. This poster presents part of the development process of this detector.

  15. On possible problems of physics, chemistry and technology of antimatter for projects of spaceships

    International Nuclear Information System (INIS)

    Full text:Great interest is paid on possibility of obtaining intensive beams of positrons (probably also other antiparticles) at reorganization of physical vacuum in strong fields (for example, in an electric field of modern super-power laser beams (http://infox.ru/science/lab/2008/11/18/antimatter.phtml) and on accelerators. It can possibly be related with creation of space solar factories on the Moon or asteroids, etc. with use of the transformed energy of radiation of the Sun to electric energy and also space for manufacture and storages of positrons. The essence of the method should consist in generation by means of the transformed energy of the Sun on accelerators or any other methods of beams of fast positrons with their subsequent delay up to temperatures of the order 0,5 K in some closed area of a space. Thus, very significant stocks of positrons could be created. Gathering of such positrons in magnetic traps in conditions of a space can become rather effective method of accumulation of antimatter by means transformations of energy of the sun (http://www.portalus.ru/modules/science/data/files/prokopiev/Project-Prokop-Paper.pdf). At the modern level of development of technologies it is not necessary to obtained much antimatter. Besides this process is very expensive. Therefore probably really to speak only about tens or hundreds nanograms of generated antimatter. This quantity of antimatter, apparently, would suffice for creation of space vehicles (SV) with the sizes in nano-or a micron range (http://www.portalus.ru/modules/science/data/files/prokopiev/Antimatter-Positronics-_ProektEngRus.doc). This fantastic assumption is not deprived sense in a context of modern development of nanotechnologies in the World. All the sizes long devices and details such SV should not exceed the sizes of nano- and micron ranges. (author)

  16. Undergraduate Laboratory Experiment: Measuring Matter Antimatter Asymmetries at the Large Hadron Collider

    CERN Document Server

    Parkes, Chris; Gutierrez, J

    2015-01-01

    This document is the student manual for a third year undergraduate laboratory experiment at the University of Manchester. This project aims to measure a fundamental difference between the behaviour of matter and antimatter through the analysis of data collected by the LHCb experiment at the Large Hadron Collider. The three-body dmecays $B^\\pm \\rightarrow h^\\pm h^+ h^-$, where $h^\\pm$ is a $\\pi^\\pm$ or $K^\\pm$ are studied. The inclusive matter antimatter asymmetry is calculated, and larger asymmetries are searched for in localized regions of the phase-space.

  17. Primordial space-time foam as an origin of cosmological matter-antimatter asymmetry

    CERN Document Server

    Ahluwalia, D V

    2001-01-01

    The possibility is raised that the observed cosmological matter-antimatter asymmetry may reside in asymmetric space-time fluctuations and their interplay with the St\\"ckelberg-Feynman interpretation of antimatter. The presented thesis also suggests that the effect of space-time fluctuations is to diminish the fine structure constant in the past. Recent studies of the QSO absorption lines provide a 4.1 standard deviation support for this prediction. Our considerations suggest that in the presence of space-time fluctuations, the principle of local gauge invariance, and the related notion of parallel transport, must undergo fundamental changes.

  18. York University atomic scientist contributes to new breakthrough in the production of antimatter

    CERN Multimedia

    2002-01-01

    Physicists working in Europe, including Canada Research Chair in Atomic Physics at York University, Prof. Eric Hessels, have succeeded in capturing the first glimpse of the structure of antimatter. The ATRAP group of scientists at CERN have managed to examine the internal states of anti-hydrogen atoms (1/2 page).

  19. Euro-led research team creates first ever reaction between matter and antimatter

    CERN Multimedia

    2006-01-01

    "An EU-funded team of international researchers has produced the first ever reaction between matter and antimatter, creating protonium. Protonium is a unique type of atom that consists of a proton and an antiproton orbiting around each other." (1 page)

  20. Chemical reaction between matter and antimatter realized for the first time: it brings about the formation of protonium

    CERN Multimedia

    2006-01-01

    "Matter and antimatter particles run into each other and they annihilate into a small flash of energy: it happened at the first light of the Universe and it happens every day in the particles accelerators throughout the world." (1 page)

  1. How to build an antimatter rocket for interstellar missions - systems level considerations in designing advanced propulsion technology vehicles

    Science.gov (United States)

    Frisbee, Robert H.

    2003-01-01

    This paper discusses the general mission requirements and system technologies that would be required to implement an antimatter propulsion system where a magnetic nozzle is used to direct charged particles to produce thrust.

  2. Experimental constraints on anti-gravity and antimatter, in the context of dark energy

    CERN Document Server

    Ting, Yuan-Sen

    2013-01-01

    In a paper by Villata (2011), the possibility of a repulsive gravitational interaction between antimatter and ordinary matter was discussed. The author argued that this anti-gravity can be regarded as a prediction of general relativity, under the assumption of CPT symmetry. Stringent experimental constraints have been established against such a suggestion. The measurement of free-fall accelerations of various nuclei by the Eot-Wash group and searches for equivalence principle violation through the gravitational splitting in kaon physics consistently establish null results on any difference between the gravitational behaviour of antimatter and ordinary matter. The original arguments against antigravity were questioned by Nieto & Goldman (1991). In the light of new experiments as well as theoretical developments in the past 20 years, some of Nieto & Goldman's concerns have been addressed. While a precise measurement of the free-fall acceleration of antihydrogen will eventually lay this issue to rest, th...

  3. Can the new Neutrino Telescopes and LHC reveal the gravitational proprieties of antimatter?

    CERN Document Server

    Hajdukovic, Dragan Slavkov

    2011-01-01

    What are the gravitational proprieties of antimatter is still not known. One possibility is the gravitational repulsion between matter and antimatter (in short we call it antigravity). We point out two possible signatures of the assumed existence of antigravity. First, the supermassive black hole in the center of our Galaxy (Southern Sky)and in the center of the Andromeda Galaxy (Northern Sky)may produce a flux of antineutrinos measurable with the new generation of the neutrino telescopes; like the IceCube Neutrino Detector under construction at the South Pole, and the future one cubic kilometer telescope in Mediterranean Sea. Second, if microscopic black holes are successfully produced at the Large Hadron Collider (LHC) at CERN, their thermal (Hawking's) radiation should be dominated by a non-thermal radiation caused by antigravity.

  4. Limits on Cosmic Matter--Antimatter Domains from Big Bang Nucleosynthesis

    OpenAIRE

    Rehm, Jan B.; Jedamzik, Karsten

    2000-01-01

    We present detailed numerical calculations of the light element abundances synthesized in a Universe consisting of matter- and antimatter- domains, as predicted to arise in some electroweak baryogenesis scenarios. In our simulations all relevant physical effects, such as baryon-antibaryon annihilations, production of secondary particles during annihilations, baryon diffusion, and hydrodynamic processes are coupled to the nuclear reaction network. We identify two dominant effects, according to...

  5. Frontiers in propulsion research: Laser, matter-antimatter, excited helium, energy exchange thermonuclear fusion

    Science.gov (United States)

    Papailiou, D. D. (Editor)

    1975-01-01

    Concepts are described that presently appear to have the potential for propulsion applications in the post-1990 era of space technology. The studies are still in progress, and only the current status of investigation is presented. The topics for possible propulsion application are lasers, nuclear fusion, matter-antimatter annihilation, electronically excited helium, energy exchange through the interaction of various fields, laser propagation, and thermonuclear fusion technology.

  6. Final Technical Report: "New Tools for Physics with Low-energy Antimatter"

    Energy Technology Data Exchange (ETDEWEB)

    Surko, Clifford M. [U. C. San Diego

    2013-10-02

    The objective of this research is to develop new tools to manipulate antimatter plasmas and to tailor them for specific scientific and technical uses. The work has two specific objectives. One is establishing the limits for positron accumulation and confinement in the form of single-component plasmas in Penning-Malmberg traps. This technique underpins a wealth of antimatter applications. A second objective is to develop an understanding of the limits for formation of cold, bright positron beams. The research done in this grant focused on particular facets of these goals. One focus was extracting tailored beams from a high-field Penning-Malmberg trap from the magnetic field to form new kinds of high-quality electrostatic beams. A second goal was to develop the technology for colder trap-based beams using a cryogenically cooled buffer gas. A third objective was to conduct the basic plasma research to develop a new high-capacity multicell trap (MCT) for research with antimatter. Progress is reported here in all three areas. While the goal of this research is to develop new tools for manipulating positrons (i.e., the antiparticles of electrons), much of the work was done with test electron plasmas for increased data rate. Some of the techniques developed in the course of this work are also relevant to the manipulation and use of antiprotons.

  7. Prospects for Studies of the Free Fall and Gravitational Quantum States of Antimatter

    Directory of Open Access Journals (Sweden)

    G. Dufour

    2015-01-01

    Full Text Available Different experiments are ongoing to measure the effect of gravity on cold neutral antimatter atoms such as positronium, muonium, and antihydrogen. Among those, the project GBAR at CERN aims to measure precisely the gravitational fall of ultracold antihydrogen atoms. In the ultracold regime, the interaction of antihydrogen atoms with a surface is governed by the phenomenon of quantum reflection which results in bouncing of antihydrogen atoms on matter surfaces. This allows the application of a filtering scheme to increase the precision of the free fall measurement. In the ultimate limit of smallest vertical velocities, antihydrogen atoms are settled in gravitational quantum states in close analogy to ultracold neutrons (UCNs. Positronium is another neutral system involving antimatter for which free fall under gravity is currently being investigated at UCL. Building on the experimental techniques under development for the free fall measurement, gravitational quantum states could also be observed in positronium. In this contribution, we report on the status of the ongoing experiments and discuss the prospects of observing gravitational quantum states of antimatter and their implications.

  8. About a problem of reception of antimatter: possibility of research f properties, synthesis and applications

    International Nuclear Information System (INIS)

    Full text: It is of special interest to study a possibility of reception of intensive streams of positrons (probably and other antiparticles) at reorganization of physical vacuum in strong fields (for example, in an electric field of modern super-power laser beams) and on accelerators. This topic can be possible related to creation of space solar factories on the Moon or asteroids, etc. with use of the solar radiation energy transformed into electric energy, and use of space for manufacturing and storages of positrons [1-7]. The essence of the method should consist of fast positron streams reception by means of the transformed solar energy on accelerators, or any other methods, with their subsequent delay up to temperatures of the order 0.5 K in some closed area of space. Thus, very significant stocks of positrons could be created. Gathering of such positrons in magnetic traps in space conditions can become rather effective method of accumulation of antimatter. Present level of technologies does not allow accumulation of received antimatter in large amounts. Besides, this reception process of is very expensive. Therefore, probably, only about ten or hundred nanograms of antimatter is yet received. This quantity of antimatter would be apparently sufficient for creation of space vehicles (SV) with the sizes in nano-or a micron range. These are not some crazy fantastic assumption in a context of modern development of nanotechnologies in the World. All the units and details of such SV should not exceed nano- and micron ranges. The situation can change, if the black holes both natural and created by the human can become 'factories' of antimatter http://www.rian.ru/rian/intro.cfm (A.D.Dolgov (ITEP) et al). Gravitation in vicinities of a black hole so is great, that there is no object, even radiation that can leave. Indeed, gravitation of a black hole acts on protons more strongly, than on electrons as their mass is larger. As a result, the black hole gets a positive

  9. Soft CP violation and the global matter-antimatter symmetry of the universe

    Science.gov (United States)

    Senjanovic, G.; Stecker, F. W.

    1980-01-01

    Scenarios for baryon production are considered within the context of SU(5) and SO(10) grand unified theories where CP violation arises spontaneously. The spontaneous CP symmetry breaking then results in a matter-antimatter domain structure in the universe. Two possible, distinct types of theories of soft CP violation are defined. In the first type the CP nonconservation originates only from the breaking of SU(2) sub L X U(1) symmetry, and in the second type, even at the unification temperature scale, CP violation can emerge as a result of symmetry breaking by the vacuum expectation values of the superheavy Higgs sector scalars.

  10. Coherent combs of anti-matter from nonlinear electron-positron pair creation

    CERN Document Server

    Krajewska, K

    2014-01-01

    Electron-positron pair creation in collisions of a modulated laser pulse with a high-energy photon (nonlinear Breit-Wheeler process) is studied by means of strong-field quantum electrodynamics. It is shown that the driving pulse modulations lead to appearance of comb structures in the energy spectra of produced positrons (electrons). It is demonstrated that these combs result from a coherent enhancement of probability amplitudes of pair creation from different modulations of the laser pulse. Thus, resembling the Young-double slit experiment for anti-matter (matter) waves.

  11. Experimental considerations for testing antimatter antigravity using positronium 1S-2S spectroscopy

    Science.gov (United States)

    Crivelli, P.; Cooke, D. A.; Friedreich, S.

    2014-05-01

    In this contribution to the WAG 2013 workshop we report on the status of our measurement of the 1S-2S transition frequency of positronium. The aim of this experiment is to reach a precision of 0.5 ppb in order to cross check the QED calculations. After reviewing the current available sources of Ps, we consider laser cooling as a route to push the precision in the measurement down to 0.1 ppb. If such an uncertainty could be achieved, this would be sensitive to the gravitational redshift and therefore be able to assess the sign of gravity for antimatter.

  12. Development and data analysis of a position detector for AE$\\bar{g}$IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy)

    CERN Document Server

    Gligorova, Angela; Doser, Michael; Pacifico, Nicola

    2015-03-13

    AE$\\mathrm{\\bar{g}}$IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is an antimatter experiment based at CERN, the European Organization for Nuclear Research, whose goal is to carry out the first direct measurement of the Earth’s gravitational acceleration on antimatter. The outcome of such measurement would be the first precision test of the Weak Equivalence Principle in a completely new area. According to WEP, all bodies fall with the same acceleration regardless of their mass and composition. AE$\\mathrm{\\bar{g}}$IS will attempt to achieve its aim by measuring the gravitational acceleration ($\\bar{g}$) for antihydrogen with 1$\\%$ relative precision. The first step towards the final goal is the formation of a pulsed, cold antihydrogen beam, which will be performed by a charge exchange reaction between laser excited (Rydberg) positronium and cold (100 mK) antiprotons. The antihydrogen atoms will be accelerated by an inhomogeneous electric field (Stark acceleration) to form a beam whose fr...

  13. Limits on Cosmic Matter--Antimatter Domains from Big Bang Nucleosynthesis

    CERN Document Server

    Rehm, J B; Rehm, Jan B.; Jedamzik, Karsten

    2001-01-01

    We present detailed numerical calculations of the light element abundances synthesized in a Universe consisting of matter- and antimatter- domains, as predicted to arise in some electroweak baryogenesis scenarios. In our simulations all relevant physical effects, such as baryon-antibaryon annihilations, production of secondary particles during annihilations, baryon diffusion, and hydrodynamic processes are coupled to the nuclear reaction network. We identify two dominant effects, according to the typical spatial dimensions of the domains. Small antimatter domains are dissipated via neutron diffusion prior to He4 synthesis at T_He4 \\approx 80 keV, leading to a suppression of the primordial He4 mass fraction. Larger domains are dissipated below T_He4 via a combination of proton diffusion and hydrodynamic expansion. In this case the strongest effects on the elemental abundances are due to anti-p He4 annihilations, leading to an overproduction of He3 relative to H2 and to overproduction of Li6 via non-thermal nuc...

  14. Mathematical Descriptions of Axially Varying Penning Traps for the Antimatter Experiment: gravity, Interferometry, and Spectroscopy

    CERN Document Server

    Stephanie, Brown

    2015-01-01

    Antimatter, though proposed in 1933, is still not well understood. AEgIS aims to study the interaction of antihydrogen with the earth's gravitational field. This information will add to our understanding of the matter-antimatter asymmetry present in our universe. This paper discusses a Penning-Malmberg with a magnetic mirror that will hold $C_{2}^{-}$ that will be used for sympathetic cooling of antiprotons before the antihydrogen is created. The trap, which is critical to the cooling process of the antihydrogen, can be characterized by the separatrix between trapped and untrapped particles. This paper applies analytical processes used to define the separatrix of pure electron plasmas to a molecular plasma. Our work is based on the desire conditions (density, particle number, field strength, trap size) of the high field region. The initial application of a semi-analytical method applied to our trap defines the trap potential difference at \\~ 0.6V. The separatrix is defined in both the high and low fiel...

  15. CP violation and the matter-antimatter asymmetry of the Universe

    Science.gov (United States)

    Hambye, Thomas

    2012-03-01

    In our everyday environment one observes only matter. That's quite a fortunate situation! Any sizeable presence of antimatter on Earth, from the enormous energy it would release through annihilation with matter, would prevent us talking about it! For the physicist this fact, at first sight obvious, is nevertheless a kind of surprise: antimatter, which is observed in cosmic rays, in radioactive decays of nuclei, which has been copiously produced and extensively studied in accelerators and which is nowadays currently used in hospitals, turns out to have pretty much the same properties as matter. Moreover, the fact that matter dominates appears to be a general property of our Universe: no evidence of large quantities of antimatter has been observed at any distance from us. Why would matter have taken the advantage on antimatter? In this short review we explain how, through a limited number of basic elements, one can find answers to this question. Matter and antimatter have, in fact, not exactly the same properties: from laboratory experiments CP conservation is known not to be a fundamental law of nature. Dans notre vie de tous les jours nous n'appréhendons que de la matière et rien ne nous indique à première vue qu'il puisse exister de l'antimatière. Bienheureux sommes nous ! La présence d'une quelconque quantité macroscopique d'antimatière autour de nous, par l'énergie qu'elle dégagerait en s'annihilant avec la matière, nous empêcherait d'être là pour en parler ! Cet état de chose est cependant une surprise pour le physicien : l'antimatière qui est aujourd'hui bien connue — étant observée et utilisée tous les jours dans les rayons cosmiques, les processus radioactifs, les accélérateurs de particules et les hôpitaux — a des propriétés très similaires à celles de la matière. De plus le fait que la matière domine apparaît être une caractéristique générale de notre univers : aucune trace d'une grande quantité d'antimatière n'a

  16. Neutrinos in the Early Universe, Kalb-Ramond Torsion and Matter-Antimatter Asymmetry

    Directory of Open Access Journals (Sweden)

    Mavromatos Nick E.

    2014-04-01

    Full Text Available The generation of a matter-antimatter asymmetry in the universe may be induced by the propagation of fermions in non-trivial, spherically asymmetric (and hence Lorentz violating gravitational backgrounds. Such backgrounds may characterise the epoch of the early universe. The key point in these models is that the background induces di_erent dispersion relations, hence populations, between fermions and antifermions, and thus CPT Violation (CPTV appears in thermal equilibrium. Species populations may freeze out leading to leptogenesis and baryogenesis. We consider here a string-inspired scenario, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond (KR antisymemtric tensor field of the string gravitational multiplet. In a four-dimensional space time this field is dual to a pseudoscalar “axionlike” field. The mixing of the KR field with an ordinary axion field can lead to the generation of a Majorana neutrino mass.

  17. The electrosphere of macroscopc ""nuclei"": diffuse emissions in the MeV band from dark antimatter

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, Michael Mcneil [Los Alamos National Laboratory; Lawson, Kyle [CANADA; Zhitnitsky, Ariel R [CANADA

    2009-01-01

    Using a Thomas-Fermi model, we calculate the structure of the electrosphere of the quark antimatter nuggets postulated to comprise much of the dark matter. This provides a single self-consistent density profile from ultra-rel ativistic densities to the non-relativistic Boltzmann regime. We use this to present a microscopically justified calculation of several properties of the nuggets, including their net charge, and the ratio of MeV to 511 keV emissions from electron annihilation. We find that the calculated parameters agree with previous phenomenological estimates based on the observational supposition that the nuggets are a source of several unexplained diffuse emissions from the galaxy. This provides another nontrivial verification of the dark matter proposal. The structure of the electrosphere is quite general and will also be valid at the surface of strange-quark stars, should they exist.

  18. Can the New Neutrino Telescopes Reveal the Gravitational Properties of Antimatter?

    Directory of Open Access Journals (Sweden)

    Dragan Slavkov Hajdukovic

    2011-01-01

    Full Text Available We argue that the hypothesis of the gravitational repulsion between matter and antimatter can be tested at the Ice Cube, a neutrino telescope, recently constructed at the South Pole. If there is such a gravitational repulsion, the gravitational field, deep inside the horizon of a black hole, might create neutrino-antineutrino pairs from the quantum vacuum. While neutrinos must stay confined inside the horizon, the antineutrinos should be violently ejected. Hence, a black hole (made from matter should behave as a point-like source of antineutrinos. Our simplified calculations suggest that the antineutrinos emitted by supermassive black holes in the centre of the Milky Way and Andromeda Galaxy could be detected by the new generation of neutrino telescopes.

  19. Search for antimatter in 1012 eV cosmic rays using Artemis method and interpretation of the cosmic rays spectrum

    International Nuclear Information System (INIS)

    This thesis is divided into three parts. The first part is a review of the present knowledge of the antimatter and of the cosmic rays. Theoretical and experimental aspects are presented. It is demonstrated that a measurement of the antimatter abundance in TeV cosmic rays is of fundamental interest, and would establish the symmetric or asymmetric nature of the Universe. The second part is dedicated to the method of antimatter research through the Earth Moon ion spectrometer (ARTEMIS). The account is given of the winter 1996-97 41-nights observation campaign undertaken at the Whipple Observatory in Arizona (USA). A 109 photomultiplier camera is operated on the 40 meter telescope to detect by Cherenkov imaging the cosmic ray initiated showers. We describe the performance of an optical filter used to reduce the noise. The development and the utilization of a simulation program are described. The main work is the analysis of the data: data characterization, understanding of the apparatus, understanding of the noise and its influence, calibration, search for signals by different methods. Subtle systematic effects are uncovered. The simulations establish that the amount of data is insufficient to reveal a shadow effect in the cosmic ray flux. The conclusion of this work is that the experimental setup was not suitable, and we propose important improvements of the method based on a bigger focal plane that would allow to reach a one percent sensitivity on the antimatter content of the cosmic rays. In the third part of the thesis, an interpretation of the total cosmic ray spectrum is proposed and discussed. (author)

  20. SN1991bg-like supernovae are a compelling source of most Galactic antimatter

    CERN Document Server

    Panther, Fiona H

    2016-01-01

    The Milky Way Galaxy glows with the soft gamma ray emission resulting from the annihilation of $\\sim 5 \\times 10^{43}$ electron-positron pairs every second. The origin of this vast quantity of antimatter and the peculiar morphology of the 511keV gamma ray line resulting from this annihilation have been the subject of debate for almost half a century. Most obvious positron sources are associated with star forming regions and cannot explain the rate of positron annihilation in the Galactic bulge, which last saw star formation some $10\\,\\mathrm{Gyr}$ ago, or else violate stringent constraints on the positron injection energy. Radioactive decay of elements formed in core collapse supernovae (CCSNe) and normal Type Ia supernovae (SNe Ia) could supply positrons matching the injection energy constraints but the distribution of such potential sources does not replicate the required morphology. We show that a single class of peculiar thermonuclear supernova - SN1991bg-like supernovae (SNe 91bg) - can supply the number...

  1. Matter-Antimatter Propulsion via QFT Effects from Parallel Electric and Magnetic Fields

    CERN Document Server

    Cleaver, Gerald B

    2016-01-01

    Matter/antimatter (MAM) pair production from the vacuum through intense electric fields has been investigated theoretically for nearly a century. This history is reviewed and proposals of MAM for intra-solar system and interstellar propulsion systems are examined. The quantum mechanical foundation of MAM production was developed by MAM production occurs when the electric field strength is above the critical value at which the fields become non-linear with self-interactions (known as the Schwinger limit).MAM production occurs when the electric field strength is above the critical value at which the fields become non-linear with self-interactions (known as the Schwinger limit). As the energy density of lasers approach the critical strength of 10^16 V/cm, the feasibility and functionality of electron-positron pair production has received growing interest. Current laser intensities are approaching within 1 order of magnitude of the Schwinger limit. Processes for lowering the critical energy density below the Schw...

  2. Antimatter and Dark Matter Search in Space: BESS-Polar Results

    Science.gov (United States)

    Mitchell, John W.; Yamamoto, Akira

    2009-01-01

    The apex of the Balloon-borne Experiment with a Superconducting Spectrometer program was reached with the Antarctic flight of BESS-Polar II, during the 2007-2008 Austral Summer, that obtained 24.5 days of data on over 4.7 billion cosmic-ray events. The US-Japan BESS Collaboration uses elementary particle measurements to study the early Universe and provides fundamental data on the spectra of light cosmic-ray elements and isotopes. BESS measures the energy spectra of cosmic-ray antiprotons to investigate signatures of possible exotic sources, such as dark-matter candidates, and searches for heavier anti-nuclei that might reach Earth from antimatter domains formed during symmetry breaking processes in the early Universe. Since 1993, BESS has carried out eleven high-latitude balloon flights, two of long duration, that together have defined the study of antiprotons below about 4 GeV, provided standard references for light element and isotope spectra, and set the most sensitive limits on the existence of anti-deuterons and anti-helium, The BESS-Polar II flight took place at Solar Minimum, when the sensitivity of the low-energy antiproton measurements to a primary source is greatest. The rich BESS-Polar II dataset more than doubles the combined data from all earlier BESS flights and has 10-20 times the statistics of BESS data from the previous Solar Minimum. Here, we summarize the scientific results of BESS program, focusing on the results obtained using data from the long-duration flights of BESS-Polar I (2004) and BESS-Polar II.

  3. QED-driven laser absorption

    CERN Document Server

    Levy, M C; Ratan, N; Sadler, J; Ridgers, C P; Kasim, M; Ceurvorst, L; Holloway, J; Baring, M G; Bell, A R; Glenzer, S H; Gregori, G; Ilderton, A; Marklund, M; Tabak, M; Wilks, S C; Norreys, P A

    2016-01-01

    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser illuminates optically-thick matter. It underpins important petawatt-scale applications today, e.g., medical-quality proton beam production. However, development of ultra-high-field applications has been hindered since no study so far has described absorption throughout the entire transition from the classical to the quantum electrodynamical (QED) regime of plasma physics. Here we present a model of absorption that holds over an unprecedented six orders-of-magnitude in optical intensity and lays the groundwork for QED applications of laser-driven particle beams. We demonstrate 58% efficient \\gamma-ray production at $1.8\\times 10^{25}~\\mathrm{W~ cm^{-2}}$ and the creation of an anti-matter source achieving $4\\times 10^{24}\\ \\mathrm{positrons}\\ \\mathrm{cm^{-3}}$, $10^{6}~\\times$ denser than of any known photonic scheme. These results will find applications in scaled laboratory probes of bla...

  4. The Discovery of Anti-Matter The Autobiography of Carl David Anderson, the Youngest Man to Win the Nobel Prize

    CERN Document Server

    1999-01-01

    In 1936, at age 31, Carl David Anderson became the second youngest Nobel laureate for his discovery of antimatter when he observed positrons in a cloud chamber.He is responsible for developing rocket power weapons that were used in World War II.He was born in New York City in 1905 and was educated in Los Angeles. He served for many years as a physics professor at California Institute of Technology. Prior to Oppenheimer, Anderson was offered the job of heading the Los Alamos atomic bomb program but could not assume the role because of family obligations.He was a pioneer in studying cosmic rays

  5. CAPRICE98: A balloon borne magnetic spectrometer to study cosmic ray antimatter and composition at different atmospheric depths

    Energy Technology Data Exchange (ETDEWEB)

    Ambriola, M.L.; Barbiellini, G.; Bartalucci, S.; Basini, G.; Bellotti, R.; Bergstroem, D.; Bocciolini, M.; Boezio, M.; Bravar, U.; Cafagna, F.; Carlson, P.; Casolino, M.; Castellano, M.; Ciacio, F.; Circella, M.; De Marzo, C.; De Pascale, M.P.; Finetti, N.; Francke, T.; Hof, M.; Kremer, J.; Menn, W.; Mitchell, J.W.; Morselli, A.; Ormes, J.F.; Papini, P.; Perego, A.; Piccardi, S.; Picozza, P.; Ricci, M.; Schiavon, P.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stephens, S.A.; Stochaj, S.J.; Streitmatter, R.E.; Suffert, M.; Vacchi, A.; Weber, N.; Zampa, N

    1999-08-01

    CAPRICE98 is a superconducting magnetic spectrometer built by the WiZard collaboration. It was launched from Ft. Sumner, NM, USA on the 28th of May 1998. For the first time a gas RICH detector has been flown together with a silicon electromagnetic calorimeter. The instrument configuration included a time of flight detector and a drift chamber stack, which were placed in the region of a magnet field, for rigidity measurement. Science objectives for this experiment include the study of antimatter in cosmic rays and that of cosmic ray composition in the atmosphere with special focus on muons.

  6. Problems of antimatter after Big Bang, dark energy and dark matter. Solutions in the frame of non-local physics

    CERN Document Server

    Alexeev, Boris V

    2010-01-01

    Quantum solitons are discovered with the help of generalized quantum hydrodynamics. The solitons have the character of the stable quantum objects in the self consistent electric field. The delivered theory demonstrates the great possibilities of the generalized quantum hydrodynamics in investigation of the quantum solitons. The theory leads to solitons as typical formations in the generalized quantum hydrodynamics. The principle of universal antigravitation is considered from positions of the Newtonian theory of gravitation and non-local kinetic theory. It is found that explanation of Hubble effect in the Universe and peculiar features of the rotational speeds of galaxies need not in introduction of new essence like dark matter and dark energy. Problems of antimatter after Big Bang are considered from positions of non-local physics. The origin of difficulties consists in total Oversimplification following from principles of local physics and reflects the general shortenings of the local kinetic transport theo...

  7. Some thoughts on the muon-catalyzed fusion process for antimatter propulsion and for the production of high A mass numbers antinuclei

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroshi

    1987-01-01

    The muon-catalyzed fusion process has a very valuable role for antiproton science and technology. Several schemes of propulsion energy enhancement of the antiproton-fueled propulsion using the muon-catalyzed fusion are discussed. Production of high A mass antinuclei by the muon-catalyzed fusion using the clustered antihydrogen molecule and quark-gluon plasma formation by annihilation of the produced high A antimatter with regular nuclei are discussed. 22 refs., 2 figs., 1 tab.

  8. Elementary process theory: a formal axiomatic system with a potential application as a foundational framework for physics supporting gravitational repulsion of matter and antimatter

    International Nuclear Information System (INIS)

    Theories of modern physics predict that antimatter having rest mass will be attracted by the earth's gravitational field, but the actual coupling of antimatter with gravitation has not been established experimentally. The purpose of the present research was to identify laws of physics that would govern the universe if antimatter having rest mass would be repulsed by the earth's gravitational field. As a result, a formalized axiomatic system was developed together with interpretation rules for the terms of the language: the intention is that every theorem of the system yields a true statement about physical reality. Seven non-logical axioms of this axiomatic system form the elementary process theory (EPT): this is then a scheme of elementary principles describing the dynamics of individual processes taking place at supersmall scale. It is demonstrated how gravitational repulsion functions in the universe of the EPT, and some observed particles and processes have been formalized in the framework of the EPT. Incompatibility of quantum mechanics (QM) and General Relativity (GR) with the EPT is proven mathematically; to demonstrate applicability to real world problems to which neither QM nor GR applies, the EPT has been applied to a theory of the Planck era of the universe. The main conclusions are that a completely formalized framework for physics has been developed supporting the existence of gravitational repulsion and that the present results give rise to a potentially progressive research program. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Antimatter H4Λ hypernucleus production and the H3Λ /3He puzzle in relativistic heavy-ion collisions

    Science.gov (United States)

    Sun, Kai-Jia; Chen, Lie-Wen

    2016-06-01

    We show that the measured yield ratio H3Λ /3He(H¯3¯Λ /¯3He ) in Au +Au collisions at √{sN N}=200 GeV and in Pb +Pb collisions at √{sN N}=2.76 TeV can be understood within a covariant coalescence model if (anti-)Λ particles freeze out earlier than (anti-)nucleons but their relative freeze-out time is closer at √{sN N}=2.76 TeV than at √{sN N}=200 GeV. The earlier (anti-)Λ freeze-out can significantly enhance the yield of (anti)hypernucleus H4Λ (H¯4¯Λ ), leading to that H¯4¯Λ has a comparable abundance with ¯4He and thus provides an easily measured antimatter candidate heavier than ¯4He. The future measurement on H4Λ (H¯4¯Λ ) would be very useful to understand the (anti-)Λ freeze-out dynamics and the production mechanism of (anti)hypernuclei in relativistic heavy-ion collisions.

  10. Particle tracking at 4 K: The Fast Annihilation Cryogenic Tracking (FACT) detector for the AEgIS antimatter gravity experiment

    Energy Technology Data Exchange (ETDEWEB)

    Storey, J., E-mail: james.storey@cern.ch [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, 3012 Bern (Switzerland); Canali, C. [University of Zurich, Physics Institute, Winterthurerstrasse 190, 8057 Zurich (Switzerland); Aghion, S. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Milano, Via Celoria 16, 20133 Milano (Italy); Ahlén, O. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Amsler, C.; Ariga, A.; Ariga, T. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, 3012 Bern (Switzerland); Belov, A.S. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation); Bonomi, G. [University of Brescia, Department of Mechanical and Industrial Engineering, Via Branze 38, 25133 Brescia (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, Via Agostino Bassi 6, 27100 Pavia (Italy); Bräunig, P. [University of Heidelberg, Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg (Germany); Bremer, J. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Brusa, R.S. [Dipartimento di Fisica, Università di Trento and INFN, Gruppo Collegato di Trento, Via Sommarive 14, 38050 Povo, Trento (Italy); Burghart, G. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Cabaret, L. [Laboratoire Aimé Cotton, CNRS, Université Paris Sud, ENS Cachan, Bâtiment 505, Campus d' Orsay, 91405 Orsay Cedex (France); Carante, M. [Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, Via Agostino Bassi 6, 27100 Pavia (Italy); Caravita, R. [University of Milano, Department of Physics, Via Celoria 16, 20133 Milano (Italy); and others

    2013-12-21

    The AEgIS experiment is an international collaboration with the main goal of performing the first direct measurement of the Earth's gravitational acceleration on antimatter. Critical to the success of AEgIS is the production of cold antihydrogen (H{sup ¯}) atoms. The FACT detector is used to measure the production and temperature of the H{sup ¯} atoms and for establishing the formation of a H{sup ¯} beam. The operating requirements for this detector are very challenging: it must be able to identify each of the thousand or so annihilations in the 1 ms period of pulsed H{sup ¯} production, operate at 4 K inside a 1 T solenoidal field and not produce more than 10 W of heat. The FACT detector consists of two concentric cylindrical layers of 400 scintillator fibres with a 1 mm diameter and a 0.6 mm pitch. The scintillating fibres are coupled to clear fibres which transport the scintillation light to 800 silicon photomultipliers. Each silicon photomultiplier signal is connected to a linear amplifier and a fast discriminator, the outputs of which are sampled continuously by Field Programmable Gate Arrays (FPGAs). In the course of the developments for the FACT detector we have established the performance of scintillating fibres at 4 K by means of a cosmic-ray tracker operating in a liquid helium cryostat. The FACT detector was installed in the AEgIS apparatus in December 2012 and will be used to study the H{sup ¯} formation when the low energy antiproton physics programs resume at CERN in the Summer of 2014. This paper presents the design requirements and construction methods of the FACT detector and provides the first results of the detector commissioning.

  11. Antimatter could fight cancer

    CERN Multimedia

    2006-01-01

    A pioneering experiment at CERN with potential future applications in cancer therapy has produced its first results. Researchers found that antiprotons are four times more effective than protons for cell irradiation.

  12. Antimatter in full view

    CERN Multimedia

    2004-01-01

    "Antiprotons confined in a magnetic trap have been imaged in 3D for the first time by researchers working on the ATHENA experiment at CERN. The new technique could have important implications for the production and detection of antihydrogen" (1 paragraph)

  13. A smattering of antimatter.

    CERN Multimedia

    Yam, P

    1996-01-01

    Physicists at CERN have succeeded in developing antihydrogen by directing a beam of antiprotons through a jet of xenon atoms. The antihydrogen results from the interaction of one antiproton with a xenon atom. However, it lasts for only 40 seconds.

  14. First antimatter chemistry

    CERN Multimedia

    2006-01-01

    "The Athena collaboration, an experimental group working at the CERN laboratory in Geneva, has measured chemical reactions involving antiprotonic hydrogen, a bound object consisting of a negatively charged antiproton paired with a positively charged proton." (1 page)

  15. ANTIMATTER - THE ULTIMATE MIRROR

    CERN Multimedia

    Gordon FRASER - ETT

    2000-01-01

    This new 200-page popular science book by CERN Courier Editor Gordon Fraser, published by Cambridge University Press, focuses on the 1995 synthesis of antihydrogen atoms at CERN and the implications of this physics. It is now available from the Reception Shop, Building 33, price SFr 30,and from the User Support Bookshop in Bldg 513 1-022, http://consult.cern.ch/service/bookshop/, for purchase via tid, edh or cash.

  16. Study of the concordance of a matter-antimatter symmetric Dirac-Milne Universe; Etude de la concordance d'un univers de Dirac-Milne symetrique matiere-antimatiere

    Energy Technology Data Exchange (ETDEWEB)

    Benoit-Levy, A.

    2009-09-15

    This thesis is devoted to the study of the Dirac-Milne Universe, a cosmological model in which matter and antimatter are present in equal quantities and where antimatter, as suggested by general relativity through the properties of the Kerr-Newman solutions, is supposed to have a negative active gravitational mass. Supposing such hypothesis removes the necessity to invoke inflation, Dark Energy and Dark matter as mandatory components. Matter (with positive mass) and antimatter (with negative mass) being present in equal quantities, the scale factor evolves linearly with time. After a short summary of basic properties of standard cosmology, some consequences of this linear evolution are studied. The full study of primordial nucleosynthesis within the framework of the Dirac-Milne universe reveals that deuterium can be produced by residual annihilations between matter and antimatter shortly before recombination. Even though Dirac-Milne universe does not present any recent acceleration of the expansion, it is shown that this model is in good agreement with the cosmological test of type Ia supernovae. It is also shown that the position of the acoustic scale of the Cosmic Microwave Background (CMB) naturally appears at the degree scale. The full study of the CMB spectrum and the coherence of the notion of negative mass remain to be investigated, but this work exhibits a original model that could potentially give an alternative description of our Universe. (author)

  17. An SO(10) × SO(10)' model for common origin of neutrino masses, ordinary and dark matter-antimatter asymmetries

    International Nuclear Information System (INIS)

    We propose an SO(10) × SO(10)' model to simultaneously realize a seesaw for Dirac neutrino masses and a leptogenesis for ordinary and dark matter-antimatter asymmetries. A (16 × 1-bar 6-bar ')H scalar crossing the SO(10) and SO(10)' sectors plays an essential role in this seesaw-leptogenesis scenario. As a result of lepton number conservation, the lightest dark nucleon as the dark matter particle should have a determined mass around 15 GeV to explain the comparable fractions of ordinary and dark matter in the present universe. The (16 × 1-bar 6-bar ')H scalar also mediates a U(1)em × U(1)'em kinetic mixing after the ordinary and dark left-right symmetry breaking so that we can expect a dark nucleon scattering in direct detection experiments and/or a dark nucleon decay in indirect detection experiments. Furthermore, we can impose a softly broken mirror symmetry to simplify the parameter choice

  18. Robotically Driven Architectural Production

    OpenAIRE

    Bier, H.H.

    2014-01-01

    Robotically driven architectural production advances seamless, computer-numerically controlled (CNC) and robotically supported design to production and operation processes enabling im-plementation of robotically driven buildings from conceptualisation to use. It enables production of free-formed, heterogeneous, optimized structures in order to address specific requirements in terms of properties (density, consistency, rigidity, etc.) and behaviours (re-configurability, responsiveness, etc.) i...

  19. Model Driven Engineering

    Science.gov (United States)

    Gaševic, Dragan; Djuric, Dragan; Devedžic, Vladan

    A relevant initiative from the software engineering community called Model Driven Engineering (MDE) is being developed in parallel with the Semantic Web (Mellor et al. 2003a). The MDE approach to software development suggests that one should first develop a model of the system under study, which is then transformed into the real thing (i.e., an executable software entity). The most important research initiative in this area is the Model Driven Architecture (MDA), which is Model Driven Architecture being developed under the umbrella of the Object Management Group (OMG). This chapter describes the basic concepts of this software engineering effort.

  20. Discovery Driven Growth

    DEFF Research Database (Denmark)

    Bukh, Per Nikolaj

    2009-01-01

    Anmeldelse af Discovery Driven Growh : A breakthrough process to reduce risk and seize opportunity, af Rita G. McGrath & Ian C. MacMillan, Boston: Harvard Business Press. Udgivelsesdato: 14 august......Anmeldelse af Discovery Driven Growh : A breakthrough process to reduce risk and seize opportunity, af Rita G. McGrath & Ian C. MacMillan, Boston: Harvard Business Press. Udgivelsesdato: 14 august...

  1. The Spin-Charge-Family theory offers the explanation for all the assumptions of the Standard model, for the Dark matter, for the Matter-antimatter asymmetry, making several predictions

    OpenAIRE

    Borštnik, Norma Susana Mankoč

    2016-01-01

    The spin-charge-family theory, which is a kind of the Kaluza-Klein theories but with fermions carrying two kinds of spins (no charges), offers the explanation for all the assumptions of the standard model, with the origin of families, the higgs and the Yukawa couplings included. It offers the explanation also for other phenomena, like the origin of the dark matter and of the matter/antimatter asymmetry in the universe. It predicts the existence of the fourth family to the observed three, as w...

  2. The Driven Spinning Top

    Science.gov (United States)

    Grosu, Ioan; Featonby, David

    2016-01-01

    This driven top is quite a novelty and can, with some trials, be made using the principles outlined here. This new top has many applications in developing both understanding and skills and these are detailed in the article. Depending on reader's available time and motivation they may feel an urge to make one themselves, or simply invest a few…

  3. Search for Antimatter in Space

    CERN Multimedia

    2002-01-01

    PAMELA is a cosmic ray space experiment that will be installed on board of the Russian satellite Resurs-DK1 whose launch is scheduled at the end of 2002. The duration of the mission will be at least three years in a high latitude orbit at an altitude ranging between 350 and 600 Km. \\\\ The observational objectives of the PAMELA experiment are the measurement of the spectra of antiprotons, positrons, particles and nuclei in a wide range of energies, the search for antinuclei and the study of the cosmic ray fluxes during a portion of a solar cycle. The main scientific objectives can be schematically summarized as follows: \\\\ \\\\ a) measurement of the antiproton spectrum in the energy range 80 MeV-190 GeV;\\\\ b) measurement of the positron spectrum in the energy range 50 MeV-270 GeV;\\\\ c) search for antinuclei with a sensitivity of the order $10^{-8}$ in the $\\overline{He}/He$ ratio;\\\\ d) measurement of the nuclei spectra (from H to C) in the energy range 100 MeV/n - 200 GeV/n;\\\\ e) energy spectrum of the electroni...

  4. Observation of an Antimatter Hypernucleus

    Energy Technology Data Exchange (ETDEWEB)

    STAR Collaboration; Abelev, Betty

    2010-07-05

    Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons - composed of an antiproton, antineutron, and antilambda hyperon - produced by colliding gold nuclei at high energy. Our analysis yields 70 {+-} 17 antihypertritons ({sub {bar {Lambda}}}{sup 3}{bar H}) and 157 {+-} 30 hypertritons ({sub {Lambda}}{sup 3}H). The measured yields of {sub {Lambda}}{sup 3}H ({sub {bar {Lambda}}}{sup 3}{bar H}) and {sup 3}He ({sup 3}{ovr He}) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and nuclei containing strange quarks, have implications spanning nuclear/particle physics, astrophysics, and cosmology.

  5. The GBAR antimatter gravity experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, P., E-mail: patrice.perez@cea.fr [Institut de Recherches sur les lois Fondamentales de l’Univers (France); Banerjee, D. [Institute for Particle Physics, ETH Zürich (Switzerland); Biraben, F. [UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Laboratoire Kastler Brossel, Collège de France (France); Brook-Roberge, D. [Institut de Recherches sur les lois Fondamentales de l’Univers (France); Charlton, M. [Swansea University, Department of Physics (United Kingdom); Cladé, P. [UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Laboratoire Kastler Brossel, Collège de France (France); Comini, P. [Institut de Recherches sur les lois Fondamentales de l’Univers (France); Crivelli, P. [Institute for Particle Physics, ETH Zürich (Switzerland); Dalkarov, O. [P. N. Lebedev Physical Institute (Russian Federation); Debu, P. [Institut de Recherches sur les lois Fondamentales de l’Univers (France); Douillet, A. [Université d’Evry Val d’Essonne, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Laboratoire Kastler Brossel, Collége de France (France); Dufour, G. [UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Laboratoire Kastler Brossel, Collège de France (France); and others

    2015-08-15

    The GBAR project (Gravitational Behaviour of Anti hydrogen at Rest) at CERN, aims to measure the free fall acceleration of ultracold neutral anti hydrogen atoms in the terrestrial gravitational field. The experiment consists preparing anti hydrogen ions (one antiproton and two positrons) and sympathetically cooling them with Be{sup +} ions to less than 10 μK. The ultracold ions will then be photo-ionized just above threshold, and the free fall time over a known distance measured. We will describe the project, the accuracy that can be reached by standard techniques, and discuss a possible improvement to reduce the vertical velocity spread.

  6. News Conference: Brecon hosts 10th teacher's conference Summer school: Science summer school heads to Crete Award: The Corti Science Prize Radioactivity: Scottish beach is no beta off Workshop: Heureka project promotes teaching Experiments: Spanish project proves that learning science can be exciting Lecture: IOP schools lecture journeys from x-rays to antimatter Correction to the news item 'Delegates experience universality' Forthcoming events

    Science.gov (United States)

    2012-01-01

    Conference: Brecon hosts 10th teacher's conference Summer school: Science summer school heads to Crete Award: The Corti Science Prize Radioactivity: Scottish beach is no beta off Workshop: Heureka project promotes teaching Experiments: Spanish project proves that learning science can be exciting Lecture: IOP schools lecture journeys from x-rays to antimatter Correction to the news item 'Delegates experience universality' Forthcoming events

  7. Solution driven versus problem driven design: strategies and outcomes

    OpenAIRE

    Kruger, Corinne; Cross, Nigel

    2006-01-01

    Data from protocol studies of nine experienced industrial designers, performing the same task, were analysed to develop an expertise model of the product design process. The protocol data and the expertise model were used to identify four different cognitive strategies employed by the designers: problem driven, solution driven, information driven, and knowledge driven design strategies. These strategies were then related to task outcomes such as solution quality and creativity, and to process...

  8. Test-driven programming

    Science.gov (United States)

    Georgiev, Bozhidar; Georgieva, Adriana

    2013-12-01

    In this paper, are presented some possibilities concerning the implementation of a test-driven development as a programming method. Here is offered a different point of view for creation of advanced programming techniques (build tests before programming source with all necessary software tools and modules respectively). Therefore, this nontraditional approach for easier programmer's work through building tests at first is preferable way of software development. This approach allows comparatively simple programming (applied with different object-oriented programming languages as for example JAVA, XML, PYTHON etc.). It is predictable way to develop software tools and to provide help about creating better software that is also easier to maintain. Test-driven programming is able to replace more complicated casual paradigms, used by many programmers.

  9. Confidence driven TGV fusion

    OpenAIRE

    Ntouskos, Valsamis; Pirri, Fiora

    2016-01-01

    We introduce a novel model for spatially varying variational data fusion, driven by point-wise confidence values. The proposed model allows for the joint estimation of the data and the confidence values based on the spatial coherence of the data. We discuss the main properties of the introduced model as well as suitable algorithms for estimating the solution of the corresponding biconvex minimization problem and their convergence. The performance of the proposed model is evaluated considering...

  10. Driven Boson Sampling

    OpenAIRE

    Barkhofen, Sonja; Bartley, Tim J.; Sansoni, Linda; Kruse, Regina; Hamilton, Craig S.; Jex, Igor; Silberhorn, Christine

    2016-01-01

    Sampling the distribution of bosons that have undergone a random unitary evolution is strongly believed to be a computationally hard problem. Key to outperforming classical simulations of this task is to increase both the number of input photons and the size of the network. We propose driven boson sampling, in which photons are input within the network itself, as a means to approach this goal. When using heralded single-photon sources based on parametric down-conversion, this approach offers ...

  11. Affinity driven social networks

    Science.gov (United States)

    Ruyú, B.; Kuperman, M. N.

    2007-04-01

    In this work we present a model for evolving networks, where the driven force is related to the social affinity between individuals of a population. In the model, a set of individuals initially arranged on a regular ordered network and thus linked with their closest neighbors are allowed to rearrange their connections according to a dynamics closely related to that of the stable marriage problem. We show that the behavior of some topological properties of the resulting networks follows a non trivial pattern.

  12. Information-Driven Inspections

    Energy Technology Data Exchange (ETDEWEB)

    Laughter, Mark D [ORNL; Whitaker, J Michael [ORNL; Lockwood, Dunbar [U.S. Department of Energy, NNSA

    2010-01-01

    New uranium enrichment capacity is being built worldwide in response to perceived shortfalls in future supply. To meet increasing safeguards responsibilities with limited resources, the nonproliferation community is exploring next-generation concepts to increase the effectiveness and efficiency of safeguards, such as advanced technologies to enable unattended monitoring of nuclear material. These include attribute measurement technologies, data authentication tools, and transmission and security methods. However, there are several conceptual issues with how such data would be used to improve the ability of a safeguards inspectorate such as the International Atomic Energy Agency (IAEA) to reach better safeguards conclusions regarding the activities of a State. The IAEA is pursuing the implementation of information-driven safeguards, whereby all available sources of information are used to make the application of safeguards more effective and efficient. Data from continuous, unattended monitoring systems can be used to optimize on-site inspection scheduling and activities at declared facilities, resulting in fewer, better inspections. Such information-driven inspections are the logical evolution of inspection planning - making use of all available information to enhance scheduled and randomized inspections. Data collection and analysis approaches for unattended monitoring systems can be designed to protect sensitive information while enabling information-driven inspections. A number of such inspections within a predetermined range could reduce inspection frequency while providing an equal or greater level of deterrence against illicit activity, all while meeting operator and technology holder requirements and reducing inspector and operator burden. Three options for using unattended monitoring data to determine an information-driven inspection schedule are to (1) send all unattended monitoring data off-site, which will require advances in data analysis techniques to

  13. Constellations-driven innovation

    DEFF Research Database (Denmark)

    Hansbøl, Mikala

    2013-01-01

    The paper presents a science and technology studies and actor-network-theory inspired approach to understanding the development and ongoing re-didactication and re-design of a Danish developed presentation tool called the Theme Board (Tematavlen.dk). It is argued that this approach provides a par...... a particularly useful point of departure for engaging in researching innovation and didactic design of digital teaching and learning instruments such as the Theme Board that are programmed and serviced 'in the sky'. I call this approach: constellation-driven innovations....

  14. Plasma-driven liners

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, H.; Linhart, J.G.; Bortolotti, A. [Ferrara Univ. (Italy). Dipt. di Fisica; Bilbao, L. [Buenos Aires Univ. (Argentina); Nardi, V. [Stevens Inst. of Tech., Hoboken, NJ (United States)

    1992-12-31

    The deposition of thermal energy by laser or ion beams in an ablator is capable of producing a very large acceleration of the adjacent pusher - for power densities of 100 Terrawatts/cm{sup 2}, ablator pressure in the range of 10 Mbar is attainable. In the case of a plasma drive such driving pressures and accelerations are not directly possible. When a snowplough (SP) is used to accelerate a thin liner, the driving pressure is that of the magnetic piston pushing the SP, i.e. at most 0.1 Mbar. However, the initial radius r{sub 0} of the liner can be a few centimeters, instead of 1 (mm) as in the case in direct pellet implosions. In order to compete with the performance of the beam-driven liners, the plasma drive must demonstrate that (a) thin liner retains a high density during the implosion (lasting a fraction of a {mu}sec); (b) radial compression ratio r{sub 0}/r{sub min} of the order of 100 can be attained. It is also attractive to consider the staging of two or more liners in order to get sharpening and amplifications of the pressure and/or radiation pulse. If (a) and (b) are verified then the final pressures produced will be comparable with those of the beam-driven implosions. (author) 5 refs., 3 figs.

  15. Plasma-driven liners

    International Nuclear Information System (INIS)

    The deposition of thermal energy by laser or ion beams in an ablator is capable of producing a very large acceleration of the adjacent pusher - for power densities of 100 Terrawatts/cm2, ablator pressure in the range of 10 Mbar is attainable. In the case of a plasma drive such driving pressures and accelerations are not directly possible. When a snowplough (SP) is used to accelerate a thin liner, the driving pressure is that of the magnetic piston pushing the SP, i.e. at most 0.1 Mbar. However, the initial radius r0 of the liner can be a few centimeters, instead of 1 (mm) as in the case in direct pellet implosions. In order to compete with the performance of the beam-driven liners, the plasma drive must demonstrate that a) thin liner retains a high density during the implosion (lasting a fraction of a μsec); b) radial compression ratio r0/rmin of the order of 100 can be attained. It is also attractive to consider the staging of two or more liners in order to get sharpening and amplifications of the pressure and/or radiation pulse. If a) and b) are verified then the final pressures produced will be comparable with those of the beam-driven implosions. (author) 5 refs., 3 figs

  16. Libration driven multipolar instabilities

    CERN Document Server

    Cébron, David; Herreman, Wietze

    2014-01-01

    We consider rotating flows in non-axisymmetric enclosures that are driven by libration, i.e. by a small periodic modulation of the rotation rate. Thanks to its simplicity, this model is relevant to various contexts, from industrial containers (with small oscillations of the rotation rate) to fluid layers of terrestial planets (with length-of-day variations). Assuming a multipolar $n$-fold boundary deformation, we first obtain the two-dimensional basic flow. We then perform a short-wavelength local stability analysis of the basic flow, showing that an instability may occur in three dimensions. We christen it the Libration Driven Multipolar Instability (LDMI). The growth rates of the LDMI are computed by a Floquet analysis in a systematic way, and compared to analytical expressions obtained by perturbation methods. We then focus on the simplest geometry allowing the LDMI, a librating deformed cylinder. To take into account viscous and confinement effects, we perform a global stability analysis, which shows that...

  17. Heat driven pulse pump

    Science.gov (United States)

    Benner, Steve M (Inventor); Martins, Mario S. (Inventor)

    2000-01-01

    A heat driven pulse pump includes a chamber having an inlet port, an outlet port, two check valves, a wick, and a heater. The chamber may include a plurality of grooves inside wall of the chamber. When heated within the chamber, a liquid to be pumped vaporizes and creates pressure head that expels the liquid through the outlet port. As liquid separating means, the wick, disposed within the chamber, is to allow, when saturated with the liquid, the passage of only liquid being forced by the pressure head in the chamber, preventing the vapor from exiting from the chamber through the outlet port. A plurality of grooves along the inside surface wall of the chamber can sustain the liquid, which is amount enough to produce vapor for the pressure head in the chamber. With only two simple moving parts, two check valves, the heat driven pulse pump can effectively function over the long lifetimes without maintenance or replacement. For continuous flow of the liquid to be pumped a plurality of pumps may be connected in parallel.

  18. Data-driven computational mechanics

    CERN Document Server

    Kirchdoerfer, Trenton

    2015-01-01

    We develop a new computing paradigm, which we refer to as data-driven computing, according to which calculations are carried out directly from experimental material data and pertinent constraints and conservation laws, such as compatibility and equilibrium, thus bypassing the empirical material modeling step of conventional computing altogether. Data-driven solvers seek to assign to each material point the state from a prespecified data set that is closest to satisfying the conservation laws. Equivalently, data-driven solvers aim to find the state satisfying the conservation laws that is closest to the data set. The resulting data-driven problem thus consists of the minimization of a distance function to the data set in phase space subject to constraints introduced by the conservation laws. We motivate the data-driven paradigm and investigate the performance of data-driven solvers by means of two examples of application, namely, the static equilibrium of nonlinear three-dimensional trusses and linear elastici...

  19. Consistent model driven architecture

    Science.gov (United States)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  20. Employee-driven innovation

    DEFF Research Database (Denmark)

    Kesting, Peter; Ulhøi, John Parm

    2015-01-01

    of contemporary research on routine and organizational decision making to the specific case of EDI. Findings – The main result of the paper is that, from a theoretical point of view, it makes perfect sense to involve ordinary employees in innovation decisions. However, it is also outlined that naıve or ungoverned......Purpose – The purpose of this paper is to outline the “grand structure” of the phenomenon in order to identify both the underlying processes and core drivers of employee-driven innovation (EDI). Design/methodology/approach – This is a conceptual paper. It particularly applies the insights...... participation is counterproductive, and that it is quite difficult to realize the hidden potential in a supportive way. Research limitations/implications – The main implication is that basic mechanisms for employee participation also apply to innovation decisions, although often in a different way. However...

  1. Driven Holographic CFTs

    CERN Document Server

    Rangamani, Mukund; Wong, Anson

    2015-01-01

    We study the dynamical evolution of strongly coupled field theories, initially in thermal equilibrium, under the influence of an external driving force. We model the field theory holographically using classical gravitational dynamics in an asymptotically AdS spacetime. The system is driven by a source for a (composite) scalar operator. We focus on a scenario where the external source is periodic in time and chart out the response of several observables. We find an interesting phase structure in the response as a function of the amplitude of the source and driving frequency. Specifically the system transitions from a dissipation dominated phase, via a dynamical crossover to a highly resonant amplification phase. The diagnostics of these phases include the response of the operator in question, entropy production, energy fluctuations, and the temporal change of entanglement entropy for small subsystems. We comment on evidence for a potential phase transition in the energy fluctuations of the system.

  2. Soliton driven angiogenesis

    Science.gov (United States)

    Bonilla, L. L.; Carretero, M.; Terragni, F.; Birnir, B.

    2016-08-01

    Angiogenesis is a multiscale process by which blood vessels grow from existing ones and carry oxygen to distant organs. Angiogenesis is essential for normal organ growth and wounded tissue repair but it may also be induced by tumours to amplify their own growth. Mathematical and computational models contribute to understanding angiogenesis and developing anti-angiogenic drugs, but most work only involves numerical simulations and analysis has lagged. A recent stochastic model of tumour-induced angiogenesis including blood vessel branching, elongation, and anastomosis captures some of its intrinsic multiscale structures, yet allows one to extract a deterministic integropartial differential description of the vessel tip density. Here we find that the latter advances chemotactically towards the tumour driven by a soliton (similar to the famous Korteweg-de Vries soliton) whose shape and velocity change slowly. Analysing these collective coordinates paves the way for controlling angiogenesis through the soliton, the engine that drives this process.

  3. Muscle-driven nanogenerators

    Science.gov (United States)

    Wang, Zhong L.; Yang, Rusen

    2011-03-01

    In a method of generating electricity, a plurality of living cells are grown on an array of piezoelectric nanowires so that the cells engage the piezoelectric nanowires. Induced static potentials are extracted from at least one of the piezoelectric nanowires when at least one of the cells deforms the at least one of the piezoelectric nanowires. A cell-driven electrical generator that includes a substrate and a plurality of spaced-apart piezoelectric nanowires disposed on the substrate. A plurality of spaced-apart conductive electrodes interact with the plurality of piezoelectric nanowires. A biological buffer layer that is configured to promote growth of cells is disposed on the substrate so that cells placed on the substrate will grow and engage the piezoelectric nanowires.

  4. Digitally-Driven Architecture

    Directory of Open Access Journals (Sweden)

    Henriette Bier

    2010-06-01

    Full Text Available The shift from mechanical to digital forces architects to reposition themselves: Architects generate digital information, which can be used not only in designing and fabricating building components but also in embedding behaviours into buildings. This implies that, similar to the way that industrial design and fabrication with its concepts of standardisation and serial production influenced modernist architecture, digital design and fabrication influences contemporary architecture. While standardisa­tion focused on processes of rationalisation of form, mass-customisation as a new paradigm that replaces mass-production, addresses non-standard, complex, and flexible designs. Furthermore, knowledge about the designed object can be encoded in digital data pertaining not just to the geometry of a design but also to its physical or other behaviours within an environment. Digitally-driven architecture implies, therefore, not only digitally-designed and fabricated architecture, it also implies architecture – built form – that can be controlled, actuated, and animated by digital means. In this context, this sixth Footprint issue examines the influence of digital means as prag­matic and conceptual instruments for actuating architecture. The focus is not so much on computer-based systems for the development of architectural designs, but on architecture incorporating digital control, sens­ing, actuating, or other mechanisms that enable buildings to inter­act with their users and surroundings in real time in the real world through physical or sensory change and variation.

  5. Invention-driven marketing

    Science.gov (United States)

    Carlson, William E.

    1994-01-01

    Suppose you have just created a revolutionary bicycle suspension which allows a bike to be ridden over rough terrain at 60 miles per hour. In addition, suppose that you are deeply concerned about the plight of hungry children. Which should you do: be sure all hungry children have bicycles; transfer the technology for your new suspension to bicycle manufacturers worldwide; or start a company to supply premium sports bicycle based on your patented technology, and donate the profits to a charity which feeds hungry children? Woven through this somewhat trivial example is the paradox of technology transfer - the supplier (owner) may want to transfer technology; but to succeed, he or she must reformulate the problem as a user need for which there is a new and better solution. Successful technology transfer is little more than good marketing applied to an existing invention, process, or capability. You must identify who needs the technology, why they need it, why the new technology is better than alternatives, how much the customers are willing and able to pay for these benefits, and how to distribute products based on the technology tc the target customers. In market-driven development, the term 'technology transfer' is rarely used. The developers focus on studying user needs and designing solution They may have technology needs, but they don't have technology in search of a use.

  6. Digitally-Driven Architecture

    Directory of Open Access Journals (Sweden)

    Henriette Bier

    2014-07-01

    Full Text Available The shift from mechanical to digital forces architects to reposition themselves: Architects generate digital information, which can be used not only in designing and fabricating building components but also in embedding behaviours into buildings. This implies that, similar to the way that industrial design and fabrication with its concepts of standardisation and serial production influenced modernist architecture, digital design and fabrication influences contemporary architecture. While standardisation focused on processes of rationalisation of form, mass-customisation as a new paradigm that replaces mass-production, addresses non-standard, complex, and flexible designs. Furthermore, knowledge about the designed object can be encoded in digital data pertaining not just to the geometry of a design but also to its physical or other behaviours within an environment. Digitally-driven architecture implies, therefore, not only digitally-designed and fabricated architecture, it also implies architecture – built form – that can be controlled, actuated, and animated by digital means.In this context, this sixth Footprint issue examines the influence of digital means as pragmatic and conceptual instruments for actuating architecture. The focus is not so much on computer-based systems for the development of architectural designs, but on architecture incorporating digital control, sens­ing, actuating, or other mechanisms that enable buildings to inter­act with their users and surroundings in real time in the real world through physical or sensory change and variation.

  7. Cosmic ray driven outflows

    CERN Document Server

    Hanasz, Michal; Naab, Thorsten; Gawryszczak, Artur; Kowalik, Kacper; Wóltański, Dominik

    2013-01-01

    We present simulations of the magnetized interstellar medium (ISM) in models of massive star forming (40 Msun / yr) disk galaxies with high gas surface densities (~100 Msun / pc^2) similar to observed star forming high-redshift disks. We assume that type II supernovae deposit 10 per cent of their energy into the ISM as cosmic rays and neglect the additional deposition of thermal energy or momentum. With a typical Galactic diffusion coefficient for CRs (3e28 cm^2 / s) we demonstrate that this process alone can trigger the local formation of a strong low density galactic wind maintaining vertically open field lines. Driven by the additional pressure gradient of the relativistic fluid the wind speed can exceed 1000 km/s, much higher than the escape velocity of the galaxy. The global mass loading, i.e. the ratio of the gas mass leaving the galactic disk in a wind to the star formation rate becomes of order unity once the system has settled into an equilibrium. We conclude that relativistic particles accelerated i...

  8. Gravity driven inflation

    CERN Document Server

    Levin, J J

    1995-01-01

    The union of high-energy particle theories and gravitation often gives rise to an evolving strength of gravity. The standard picture of the earliest universe would certainly deserve revision if the Planck mass, which defines the strength of gravity, varied. A notable consequence is a gravity-driven, kinetic inflation. Unlike standard inflation, there is no potential nor cosmological constant. The unique elasticity in the kinetic energy of the Planck mass provides a negative pressure able to drive inflation. As the kinetic energy grows, the spacetime expands more quickly. The phenomenon of kinetic inflation has been uncovered in both string theory and Kaluza-Klein theories. The difficulty in exiting inflation in these cases is reviewed. General forms of the Planck field coupling are shown to avoid the severity of the graceful exit problem found in string and Kaluza-Klein theories. The completion of the model is foreshadowed with a suggestion for a heating mechanism to generate the hot soup of the big bang.

  9. Customer-driven competition

    International Nuclear Information System (INIS)

    Ontario Hydro's customer-driven strategy, recently approved by Hydro's Executive Board, was described. The strategy is founded on the following components: (1) the dissolution of the Ontario power pool, i.e., the loss of Hydro's franchise monopoly on generation, leaving only power transmission in the hands of the Corporation, (2) divestment of Ontario Hydro's system operations and market operations functions to a new, independent Crown corporation called the Central Market Operator, (3) functional and organizational unbundling of Ontario Hydro into three signature businesses, Genco, Transco, and Retailco, and in the latter two, the functional unbundling of wires from sales and services, (4) a fully commercial Ontario Hydro with normal corporate powers, and (5) a corporate strategy for Ontario Hydro to grow in businesses in an open, symmetrical North American energy market. According to Ontario Hydro management this will allow competition and choice to all customers, have a disciplining effect on prices, and give rise to a retail market of new products and services, while at the same time preserve and enhance the value of public investment in the Corporation

  10. Salinity driven oceanographic upwelling

    Science.gov (United States)

    Johnson, D.H.

    1984-08-30

    The salinity driven oceanographic upwelling is maintained in a mariculture device that includes a long main duct in the general shape of a cylinder having perforated cover plates at each end. The mariculture device is suspended vertically in the ocean such that one end of the main duct is in surface water and the other end in relatively deep water that is cold, nutrient rich and relatively fresh in comparison to the surface water which is relatively warm, relatively nutrient deficient and relatively saline. A plurality of elongated flow segregating tubes are disposed in the main duct and extend from the upper cover plate beyond the lower cover plate into a lower manifold plate. The lower manifold plate is spaced from the lower cover plate to define a deep water fluid flow path to the interior space of the main duct. Spacer tubes extend from the upper cover plate and communicate with the interior space of the main duct. The spacer tubes are received in an upper manifold plate spaced from the upper cover plate to define a surface water fluid flow path into the flow segregating tubes. A surface water-deep water counterflow is thus established with deep water flowing upwardly through the main duct interior for discharge beyond the upper manifold plate while surface water flows downwardly through the flow segregating tubes for discharge below the lower manifold plate. During such counterflow heat is transferred from the downflowing warm water to the upflowing cold water. The flow is maintained by the difference in density between the deep water and the surface water due to their differences in salinity. The upwelling of nutrient rich deep water is used for marifarming by fertilizing the nutrient deficient surface water. 1 fig.

  11. Salinity driven oceanographic upwelling

    Science.gov (United States)

    Johnson, David H.

    1986-01-01

    The salinity driven oceanographic upwelling is maintained in a mariculture device that includes a long main duct in the general shape of a cylinder having perforated cover plates at each end. The mariculture device is suspended vertically in the ocean such that one end of the main duct is in surface water and the other end in relatively deep water that is cold, nutrient rich and relatively fresh in comparison to the surface water which is relatively warm, relatively nutrient deficient and relatively saline. A plurality of elongated flow segregating tubes are disposed in the main duct and extend from the upper cover plate beyond the lower cover plate into a lower manifold plate. The lower manifold plate is spaced from the lower cover plate to define a deep water fluid flow path to the interior space of the main duct. Spacer tubes extend from the upper cover plate and communicate with the interior space of the main duct. The spacer tubes are received in an upper manifold plate spaced from the upper cover plate to define a surface water fluid flow path into the flow segregating tubes. A surface water-deep water counterflow is thus established with deep water flowing upwardly through the main duct interior for discharge beyond the upper manifold plate while surface water flows downwardly through the flow segregating tubes for discharge below the lower manifold plate. During such counterflow heat is transferred from the downflowing warm water to the upflowing cold water. The flow is maintained by the difference in density between the deep water and the surface water due to their differences in salinity. The upwelling of nutrient rich deep water is used for marifarming by fertilizing the nutrient deficient surface water.

  12. The Spin-Charge-Family theory offers the explanation for all the assumptions of the Standard model, for the Dark matter, for the Matter-antimatter asymmetry, making several predictions

    CERN Document Server

    Borštnik, Norma Susana Mankoč

    2016-01-01

    The spin-charge-family theory, which is a kind of the Kaluza-Klein theories but with fermions carrying two kinds of spins (no charges), offers the explanation for all the assumptions of the standard model, with the origin of families, the higgs and the Yukawa couplings included. It offers the explanation also for other phenomena, like the origin of the dark matter and of the matter/antimatter asymmetry in the universe. It predicts the existence of the fourth family to the observed three, as well as several scalar fields with the weak and the hyper charge of the standard model higgs ($\\pm \\frac{1}{2}, \\mp \\frac{1}{2}$, respectively), which determine the mass matrices of family members, offering an explanation, why the fourth family with the masses above $1$ TeV contributes weakly to the gluon-fusion production of the observed higgs and to its decay into two photons, and predicting that the two photons events, observed at the LHC at $\\approx 750$ GeV, might be an indication for the existence of one of several s...

  13. Economics-driven software architecture

    CERN Document Server

    Mistrik, Ivan; Kazman, Rick; Zhang, Yuanyuan

    2014-01-01

    Economics-driven Software Architecture presents a guide for engineers and architects who need to understand the economic impact of architecture design decisions: the long term and strategic viability, cost-effectiveness, and sustainability of applications and systems. Economics-driven software development can increase quality, productivity, and profitability, but comprehensive knowledge is needed to understand the architectural challenges involved in dealing with the development of large, architecturally challenging systems in an economic way. This book covers how to apply economic consider

  14. Data-driven batch schuduling

    Energy Technology Data Exchange (ETDEWEB)

    Bent, John [Los Alamos National Laboratory; Denehy, Tim [GOOGLE; Arpaci - Dusseau, Remzi [UNIV OF WISCONSIN; Livny, Miron [UNIV OF WISCONSIN; Arpaci - Dusseau, Andrea C [NON LANL

    2009-01-01

    In this paper, we develop data-driven strategies for batch computing schedulers. Current CPU-centric batch schedulers ignore the data needs within workloads and execute them by linking them transparently and directly to their needed data. When scheduled on remote computational resources, this elegant solution of direct data access can incur an order of magnitude performance penalty for data-intensive workloads. Adding data-awareness to batch schedulers allows a careful coordination of data and CPU allocation thereby reducing the cost of remote execution. We offer here new techniques by which batch schedulers can become data-driven. Such systems can use our analytical predictive models to select one of the four data-driven scheduling policies that we have created. Through simulation, we demonstrate the accuracy of our predictive models and show how they can reduce time to completion for some workloads by as much as 80%.

  15. Surface tension driven convection experiment

    Science.gov (United States)

    Ostrach, Simon; Kamotani, Yasuhiro

    1988-01-01

    Thermocapillary flow is driven by a thermally induced surface tension variation along a liquid free surface. In the Earth-gravity environment such flows are usually overshadowed by buoyancy driven flows, but at reduced gravity conditions their influence could be significant. A comprehensive theoretical and experimental research program was stated 12 years ago and is still being continued. Past work done at Case Western Reserve University as well as work done by others is reviewed. The justification for low-gravity experiments is presented.

  16. Driven shielding capacitive proximity sensor

    Science.gov (United States)

    Vranish, John M. (Inventor); McConnell, Robert L. (Inventor)

    2000-01-01

    A capacitive proximity sensing element, backed by a reflector driven at the same voltage as and in phase with the sensor, is used to reflect the field lines away from a grounded robot arm towards an intruding object, thus dramatically increasing the sensor's range and sensitivity.

  17. Effects-Driven IT Development

    DEFF Research Database (Denmark)

    Hertzum, Morten; Simonsen, Jesper

    2011-01-01

    For customers information technology (IT) is a means to an end. This tight association between IT systems and their use is, however, often absent during their development and implementation, resulting in systems that may fail to produce desired ends. Effects-driven IT development aims to avoid...

  18. Pattern Formation in Driven Systems

    Science.gov (United States)

    Klymko, Katherine

    Model colloidal particles of two types, driven in opposite directions, will in two dimensions segregate into lanes, a phenomenon studied extensively by Lowen and co-workers [Dzubiella et al. Phys. Rev. E 65, 021402 (2002)]. We have simulated mixtures of oppositely-driven particles using three numerical protocols. We find that laning results from enhanced diffusion, in the direction perpendicular to the drive, of particles surrounded by particles of the opposite type, consistent with the observation of Vissers et al. [Soft Matter 7, 6, 2352 (2011)]. By comparing protocols we find that enhanced diffusion follows from a simple geometrical constraint: oppositely-driven particles must, in the time taken to encounter each other in the direction of the drive, diffuse in the perpendicular direction by about one particle diameter. This constraint implies that the effective lateral diffusion constant grows linearly with drive speed and as the square root of the packing fraction, a prediction supported by our numerics. By invoking an analogy between hard particles with environment-dependent mobilities and mutually attractive particles we argue that there exists an equilibrium system whose pattern-forming properties are similar to those of the driven system. Katherine Klymko acknowledges support from the NSF Graduate Research Fellowship.

  19. Improved data driven control charts

    NARCIS (Netherlands)

    Albers, W.; Kallenberg, W.C.M.

    2007-01-01

    Classical control charts for monitoring the mean are based on the assumption of normality. When normality fails, these control charts are no longer valid and serious errors often arise. Data driven control charts, which choose between the normal chart, a parametric one and a nonparametric chart, hav

  20. Track guided self-driven container wagon

    NARCIS (Netherlands)

    Hansen, I.A.

    1999-01-01

    The linear motor consists of a series of stator coils (2) located along the Track guided self-driven container wagon Track guided self-driven container wagon track and a reaction rail (3) fitted under the wagon chassis (4).

  1. Schematic driven silicon photonics design

    Science.gov (United States)

    Chrostowski, Lukas; Lu, Zeqin; Flückiger, Jonas; Pond, James; Klein, Jackson; Wang, Xu; Li, Sarah; Tai, Wei; Hsu, En Yao; Kim, Chan; Ferguson, John; Cone, Chris

    2016-03-01

    Electronic circuit designers commonly start their design process with a schematic, namely an abstract representation of the physical circuit. In integrated photonics on the other hand, it is very common for the design to begin at the physical component level. In order to build large integrated photonic systems, it is crucial to design using a schematic-driven approach. This includes simulations based on schematics, schematic-driven layout, layout versus schematic verification, and post-layout simulations. This paper describes such a design framework implemented using Mentor Graphics and Lumerical Solutions design tools. In addition, we describe challenges in silicon photonics related to manufacturing, and how these can be taken into account in simulations and how these impact circuit performance.

  2. Effects-Driven IT Development

    DEFF Research Database (Denmark)

    Hertzum, Morten; Simonsen, Jesper

    2010-01-01

    We present effects-driven IT development as an instrument for pursuing and reinforcing Participatory Design (PD) when it is applied in commercial information technology (IT) projects. Effects-driven IT development supports the management of a sustained PD process throughout design and...... organizational implementation. The focus is on the effects to be achieved by users through their adoption and use of a system. The overall idea is to (a) specify the purpose of a system as effects that are both measurable and meaningful to the users, and (b) evaluate the absence or presence of these effects...... during real use of the system. Effects are formulated in a user-oriented terminology, and they can be evaluated and revised with users in an iterative and incremental systems-development process that involves pilot implementations. In this paper we investigate the design, pilot implementation, and...

  3. Model-Driven Constraint Programming

    CERN Document Server

    Chenouard, Raphael; Soto, Ricardo; 10.1145/1389449.1389479

    2010-01-01

    Constraint programming can definitely be seen as a model-driven paradigm. The users write programs for modeling problems. These programs are mapped to executable models to calculate the solutions. This paper focuses on efficient model management (definition and transformation). From this point of view, we propose to revisit the design of constraint-programming systems. A model-driven architecture is introduced to map solving-independent constraint models to solving-dependent decision models. Several important questions are examined, such as the need for a visual highlevel modeling language, and the quality of metamodeling techniques to implement the transformations. A main result is the s-COMMA platform that efficiently implements the chain from modeling to solving constraint problems

  4. Kaehler-driven tribrid inflation

    International Nuclear Information System (INIS)

    We discuss a new class of tribrid inflation models in supergravity, where the shape of the inflaton potential is dominated by effects from the Kaehler potential. Tribrid inflation is a variant of hybrid inflation which is particularly suited for connecting inflation with particle physics, since the inflaton can be a D-flat combination of charged fields from the matter sector. In models of tribrid inflation studied so far, the inflaton potential was dominated by either loop corrections or by mixing effects with the waterfall field (as in 'pseudosmooth' tribrid inflation). Here we investigate the third possibility, namely that tribrid inflation is dominantly driven by effects from higher-dimensional operators of the Kaehler potential. We specify for which superpotential parameters the new regime is realized and show how it can be experimentally distinguished from the other two (loop-driven and pseudosmooth) regimes

  5. Noise-driven quantum criticality

    OpenAIRE

    J. Eisert; Prosen, T.

    2010-01-01

    We discuss a notion of quantum critical exponents in open quantum many-body systems driven by quantum noise. We show that in translationally invariant quantum lattice models undergoing quasi-local Markovian dissipative processes, mixed states emerge as stationary points that show scaling laws for the divergence of correlation lengths giving rise to well-defined critical exponents. The main new technical tool developed here is a complete description of steady states of free bosonic or fermioni...

  6. Security and policy driven computing

    CERN Document Server

    Liu, Lei

    2010-01-01

    Security and Policy Driven Computing covers recent advances in security, storage, parallelization, and computing as well as applications. The author incorporates a wealth of analysis, including studies on intrusion detection and key management, computer storage policy, and transactional management.The book first describes multiple variables and index structure derivation for high dimensional data distribution and applies numeric methods to proposed search methods. It also focuses on discovering relations, logic, and knowledge for policy management. To manage performance, the text discusses con

  7. Consumption-Driven Market Emergence

    OpenAIRE

    Diane M. Martin; Schouten, John W

    2014-01-01

    New market development is well theorized from a firm-centered perspective, but research has paid scant attention to the emergence of markets from consumption activity. The exceptions conceptualize market emergence as a product of consumer struggle against prevailing market logics. This study develops a model of consumption-driven market emergence in harmony with existing market offerings. Using ethnographic methods and actor-network theory the authors chronicle the emergence of a new market w...

  8. Community-driven online service

    OpenAIRE

    Tuunanen, Jarkko

    2014-01-01

    The purpose of this thesis was to implement a community-driven online service for a fashion magazine. The aim was to create the number one fashion and beauty related online service in Finland. The online service consists of two platforms. The core of the service is built on top of Drupal content management system. Wordpress was selected as the platform for the blogs. The user interfaces for both were designed and implemented to be responsive. Layout management in Drupal is challenging...

  9. Active and driven hydrodynamic crystals.

    Science.gov (United States)

    Desreumaux, N; Florent, N; Lauga, E; Bartolo, D

    2012-08-01

    Motivated by the experimental ability to produce monodisperse particles in microfluidic devices, we study theoretically the hydrodynamic stability of driven and active crystals. We first recall the theoretical tools allowing to quantify the dynamics of elongated particles in a confined fluid. In this regime hydrodynamic interactions between particles arise from a superposition of potential dipolar singularities. We exploit this feature to derive the equations of motion for the particle positions and orientations. After showing that all five planar Bravais lattices are stationary solutions of the equations of motion, we consider separately the case where the particles are passively driven by an external force, and the situation where they are self-propelling. We first demonstrate that phonon modes propagate in driven crystals, which are always marginally stable. The spatial structures of the eigenmodes depend solely on the symmetries of the lattices, and on the orientation of the driving force. For active crystals, the stability of the particle positions and orientations depends not only on the symmetry of the crystals but also on the perturbation wavelengths and on the crystal density. Unlike unconfined fluids, the stability of active crystals is independent of the nature of the propulsion mechanism at the single-particle level. The square and rectangular lattices are found to be linearly unstable at short wavelengths provided the volume fraction of the crystals is high enough. Differently, hexagonal, oblique, and face-centered crystals are always unstable. Our work provides a theoretical basis for future experimental work on flowing microfluidic crystals. PMID:22864543

  10. Edge-driven microplate kinematics

    Science.gov (United States)

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  11. Capacitive Proximity Sensors With Additional Driven Shields

    Science.gov (United States)

    Mcconnell, Robert L.

    1993-01-01

    Improved capacitive proximity sensors constructed by incorporating one or more additional driven shield(s). Sensitivity and range of sensor altered by adjusting driving signal(s) applied to shield(s). Includes sensing electrode and driven isolating shield that correspond to sensing electrode and driven shield.

  12. Is "Market-Driven" Good Enough?

    Science.gov (United States)

    Kaufman, Roger

    1995-01-01

    Discusses marketing and management strategies and evaluates the path most traveled; going beyond market-driven; proactive and reactive organizational positioning; ways to manage human and physical resources to make both market-driven and market-making contributions; and values necessary for an organization to move from market-driven to…

  13. Ontology-Driven Information Integration

    Science.gov (United States)

    Tissot, Florence; Menzel, Chris

    2005-01-01

    Ontology-driven information integration (ODII) is a method of computerized, automated sharing of information among specialists who have expertise in different domains and who are members of subdivisions of a large, complex enterprise (e.g., an engineering project, a government agency, or a business). In ODII, one uses rigorous mathematical techniques to develop computational models of engineering and/or business information and processes. These models are then used to develop software tools that support the reliable processing and exchange of information among the subdivisions of this enterprise or between this enterprise and other enterprises.

  14. Data driven marketing for dummies

    CERN Document Server

    Semmelroth, David

    2013-01-01

    Embrace data and use it to sell and market your products Data is everywhere and it keeps growing and accumulating. Companies need to embrace big data and make it work harder to help them sell and market their products. Successful data analysis can help marketing professionals spot sales trends, develop smarter marketing campaigns, and accurately predict customer loyalty. Data Driven Marketing For Dummies helps companies use all the data at their disposal to make current customers more satisfied, reach new customers, and sell to their most important customer segments more efficiently. Identifyi

  15. Employee-Driven Innovation (EDI)

    DEFF Research Database (Denmark)

    Kesting, Peter; Ulhøi, John Parm

      The responsibility to be innovative and think of useful ideas and the privilege of making decisions in processes of innovation are typically restricted to specifically assigned R&D functions and/or upper echelon managers. Given the importance of innovation to most organizations, it may seem...... illogical to reserve such a 'license' to so few individuals. This paper argues that some parts of that license should indeed be extended to include 'ordinary' employees, as they are potential drivers of innovation. Research on Employee Driven Innovation (EDI) is still at its beginnings. In the paper we...

  16. On Rank Driven Dynamical Systems

    Science.gov (United States)

    Veerman, J. J. P.; Prieto, F. J.

    2014-08-01

    We investigate a class of models related to the Bak-Sneppen (BS) model, initially proposed to study evolution. The BS model is extremely simple and yet captures some forms of "complex behavior" such as self-organized criticality that is often observed in physical and biological systems. In this model, random fitnesses in are associated to agents located at the vertices of a graph . Their fitnesses are ranked from worst (0) to best (1). At every time-step the agent with the worst fitness and some others with a priori given rank probabilities are replaced by new agents with random fitnesses. We consider two cases: The exogenous case where the new fitnesses are taken from an a priori fixed distribution, and the endogenous case where the new fitnesses are taken from the current distribution as it evolves. We approximate the dynamics by making a simplifying independence assumption. We use Order Statistics and Dynamical Systems to define a rank-driven dynamical system that approximates the evolution of the distribution of the fitnesses in these rank-driven models, as well as in the BS model. For this simplified model we can find the limiting marginal distribution as a function of the initial conditions. Agreement with experimental results of the BS model is excellent.

  17. Piezoelectrically-driven Thermoacoustic Refrigerator

    Science.gov (United States)

    Chinn, Daniel George

    Thermoacoustic refrigeration is an emerging refrigeration technology which does not require any moving parts or harmful refrigerants in its operation. This technology uses acoustic waves to pump heat across a temperature gradient. The vast majority of thermoacoustic refrigerators to date have used electromagnetic loudspeakers to generate the acoustic input. In this thesis, the design, construction, operation, and modeling of a piezoelectrically-driven thermoacoustic refrigerator are detailed. This refrigerator demonstrates the effectiveness of piezoelectric actuation in moving 0.3 W of heat across an 18 degree C temperature difference with an input power of 7.6 W. The performance characteristics of this class of thermoacoustic-piezoelectric refrigerators are modeled by using DeltaEC software and the predictions are experimentally validated. The obtained results confirm the validity of the developed model. Furthermore, the potential of piezoelectric actuation as effective means for driving thermoacoustic refrigerators is demonstrated as compared to the conventional electromagnetic loudspeakers which are heavy and require high actuation energy. The developed theoretical and experimental tools can serve as invaluable means for the design and testing of other piezoelectrically-driven thermoacoustic refrigerator configurations.

  18. Investigating Reaction-Driven Cracking

    Science.gov (United States)

    Kelemen, P. B.; Hirth, G.; Savage, H. M.

    2013-12-01

    Many metamorphic reactions lead to large volume changes, and potentially to reaction-driven cracking [1,2]. Large-scale hydration of mantle peridotite to produce serpentine or talc is invoked to explain the rheology of plate boundaries, the nature of earthquakes, and the seismic properties of slow-spread ocean crust and the 'mantle wedge' above subduction zones. Carbonation of peridotite may be an important sink in the global carbon cycle. Zones of 100% magnesite + quartz replacing peridotite, up to 200 m thick, formed where oceanic mantle was thrust over carbonate-bearing metasediments in Oman. Talc + carbonate is an important component of the matrix in subduction mélanges at Santa Catalina Island , California, and the Sanbagawa metamorphic belt, Japan. Engineered systems to emulate natural mineral carbonation could provide relatively inexpensive CO2 capture and storage [3]. More generally, engineered reaction-driven cracking could supplement or replace hydraulic fracture in geothermal systems, solution mining, and extraction of tight oil and gas. The controls on reaction-driven cracking are poorly understood. Hydration and carbonation reactions can be self-limiting, since they potentially reduce permeability and armor reactive surfaces [4]. Also, in some cases, hydration or carbonation may take place at constant volume. Small changes in volume due to precipitation of solid products increases stress, destabilizing solid reactants, until precipitation and dissolution rates become equal at a steady state stress [5]. In a third case, volume change due to precipitation of solid products causes brittle failure. This has been invoked on qualitative grounds to explain, e.g., complete serpentinization of mantle peridotite [6]. Below ~ 300°C, the available potential energy for hydration and carbonation of olivine could produce stresses of 100's of MPa [2], sufficient to fracture rocks to 10 km depth or more, causing brittle failure below the steady state stress required

  19. Facts about real antimatter collide with fiction

    CERN Multimedia

    Siegfried, Tom

    2004-01-01

    When science collides with fiction, sometimes a best seller emerges from the debris. Take Dan Brown's Angels & Demons, for instance, a murder mystery based on science at CERN, the European nuclear research laboratory outside Geneva

  20. Atomic processes in matter-antimatter interactions

    International Nuclear Information System (INIS)

    Atomic processes dominate antiproton stopping in matter at nearly all energies of interest. They significantly influence or determine the antiproton annihilation rate at all energies around or below several MeV. This article reviews what is known about these atomic processes. For stopping above about 10 eV the processes are antiproton-electron collisions, effective at medium keV through high MeV energies, and elastic collisions with atoms and adiabatic ionization of atoms, effective from medium eV through low keB energies. For annihilation above about 10 eV is the enhancement of the antiproton annihilation rate due to the antiproton-nucleus coulomb attraction, effective around and below a few tens of MeV. At about 10 eV and below, the atomic rearrangement/annihilation process determines both the stopping and annihilation rates. Although a fair amount of theoretical and some experimental work relevant to these processes exist, there are a number of energy ranges and material types for which experimental data does not exist and for which the theoretical information is not as well grounded or as accurate as desired. Additional experimental and theoretical work is required for accurate prediction of antiproton stopping and annihilation for energies and material relevant to antiproton experimentation and application

  1. NASA declares no room for antimatter experiment

    CERN Multimedia

    Law??, Andrew

    2007-01-01

    "The Alpha Magnetic Spectrometer (AMS) is a model of international cooperation, led by a dynamic Nobel Prize winner, and promises to do impressive science in space. But it may never get a chance to do its thing." (1 page)

  2. Understand antimatter better #13TeV

    CERN Document Server

    2015-01-01

    Follow Italian @LHCbexperiment physicist Barbara Storaci from the University of Zürich, Switzerland, as she shares her thoughts about the new physics frontiers opening up now that the LHC has collisions at the higher energy of #13TeV. Each week a new video will be uploaded to https://www.youtube.com/playlist?list... allowing you to follow physicists from @ATLASexperiment @ALICEexperiment @CMSexperiment or @LHCbExperiment as they search the new frontiers in physics. Read more about these new frontiers in physics: http://cern.ch/go/x8VH

  3. Matter-antimatter: balancing the scales

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Using its innovative experimental set-up, the Japanese-European ASACUSA collaboration recently succeeded in measuring the mass of the antiprotons with an unprecedented accuracy. This has been made possible by applying extremely high-precision laser techniques.   ASACUSA physicist, Masaki Hori, adjusts the optical system of laser beams. The antiproton is not something you could weigh by putting it on a pair of scales. Besides, it is not its “weight” (i.e. the Earth’s gravitational force on it) that scientists aim to measure but rather its “mass”. In addition, the yardstick against which the antiproton mass was measured is not the familiar kilogram, but the electron’s mass. Technically speaking, this is no easy task, especially when an unprecedented precision is requested. In the ASACUSA experiment, two counter-propagating ultra-sharp laser beams simultaneously hit an antiprotonic helium atom, where an antiproton orbits around the nuc...

  4. Antimatter signatures of gravitino dark matter decay

    International Nuclear Information System (INIS)

    The scenario of gravitino dark matter with broken R-parity naturally reconciles three paradigms that, albeit very well motivated separately, seem to be in mutual conflict: supersymmetric dark matter, thermal leptogenesis and standard big bang nucleosynthesis. Interestingly, the products of the gravitino decay could be observed, opening the possibility of indirect detection of gravitino dark matter. In this paper, we compute the positron and the antiproton fluxes from gravitino decay. We find that a gravitino with a mass of m3/2∼150 GeV and a lifetime of τ3/2∼1026 s could simultaneously explain the EGRET anomaly in the extragalactic diffuse gamma ray background and the HEAT excess in the positron fraction. However, the predicted antiproton flux tends to be too large, although the prediction suffers from large uncertainties and might be compatible with present observations for certain choices of propagation parameters

  5. Test driven software development with Java EE

    OpenAIRE

    Balantič, Matija

    2013-01-01

    Test driven development (TDD) is a technique with the main idea of writing a failing test first, which is then made to pass by implementing a particular snippet of code. Development is done in short iterations which consist of three basic steps, namely test-code-refactor. The thesis shows the development of Java EE web applications FerApp using test driven development and continuous integration. The application development was driven with unit tests and complemented with integration and f...

  6. Design Driven Testing Test Smarter, Not Harder

    CERN Document Server

    Stephens, M

    2010-01-01

    The groundbreaking book Design Driven Testing brings sanity back to the software development process by flipping around the concept of Test Driven Development (TDD) - restoring the concept of using testing to verify a design instead of pretending that unit tests are a replacement for design. Anyone who feels that TDD is "Too Damn Difficult" will appreciate this book. Design Driven Testing shows that, by combining a forward-thinking development process with cutting-edge automation, testing can be a finely targeted, business-driven, rewarding effort. In other words, you'll learn how to test

  7. Disentangling Competition Among Platform Driven Strategic Groups

    DEFF Research Database (Denmark)

    Kazan, Erol; Tan, Chee-Wee; Lim, Eric

    2015-01-01

    competition within platform-driven markets, we opted for the UK mobile payment market as our empirical setting. By embracing the theoretical lens of strategic groups and digital platforms, this study supplements prior research by deriving a taxonomy of platform-driven strategic groups that is grounded......In platform-driven markets, competitive advantage is derived from superior platform design and configurations. For this reason, platform owners strive to create unique and inimitable platform configurals to maintain and extend their competitiveness within network economies. To disentangle firm...... on competitive attributes of platform- driven markets; namely interfirm modularity and strategic linkages....

  8. Coevolutionary success-driven multigames

    CERN Document Server

    Szolnoki, Attila

    2014-01-01

    Wealthy individuals may be less tempted to defect than those with comparatively low payoffs. To take this into consideration, we introduce coevolutionary success-driven multigames in structured populations. While the core game is always the weak prisoner's dilemma, players whose payoffs from the previous round exceed a threshold adopt only a minimally low temptation to defect in the next round. Along with the strategies, the perceived strength of the social dilemma thus coevolves with the success of each individual player. We show that the lower the threshold for using the small temptation to defect, the more the evolution of cooperation is promoted. Importantly, the promotion of cooperation is not simply due to a lower average temptation to defect, but rather due to a dynamically reversed direction of invasion along the interfaces that separate cooperators and defectors on regular networks. Conversely, on irregular networks, in the absence of clear invasion fronts, the promotion of cooperation is due to inte...

  9. Photogated humidity-driven motility

    Science.gov (United States)

    Zhang, Lidong; Liang, Haoran; Jacob, Jolly; Naumov, Panče

    2015-06-01

    Hygroinduced motion is a fundamental process of energy conversion that is essential for applications that require contactless actuation in response to the day-night rhythm of atmospheric humidity. Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light. A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min-1. The element can lift objects ~85 times heavier and can transport cargos ~20 times heavier than itself. Having an azobenzene-containing conjugate as a photoactive dopant, this entirely humidity-driven self-actuation can be controlled remotely with ultraviolet light, thus setting a platform for next-generation smart biomimetic hybrids.

  10. Driven Random Field Ising Model:

    Science.gov (United States)

    Shukla, Prabodh

    The random field Ising Model (RFIM) driven by a slowly varying uniform external field at zero temperature provides a caricature of several threshold activated systems. In this model, the non-equilibrium response of the system can be obtained analytically in one dimension as well as on a Bethe lattice if the initial state of the system has all spins aligned parallel to each other. We consider ferromagnetic as well as anti-ferromagnetic interactions. The ferromagnetic model exhibits avalanches and non-equilibrium critical behavior. The anti-ferromagnetic model is marked by the absence of these features. The ferromagnetic model is Abelian, and the anti-ferromagnetic model is non-Abelian. Theoretical approaches based on the probabilistic method are discussed in the two cases, and illustrated by deriving some basic results.

  11. Customer-driven Product Development

    DEFF Research Database (Denmark)

    Sommer, Anita Friis

    2011-01-01

    Demand chain management is a research area of increasing attention. It is the undertaking of reacting to customer requirements through a responsive chain going from customers through a focal company towards raw material distributors. With faster growing markets and increasing competition, companies...... look for new ways to gain competitive advantage. In competitive markets there is a tendency of shorter product life cycles, and thus a competitive factor is to keep at pace with the market or even driving the market by developing new products. This research study seeks to investigate Customer......-driven Product Development (CDPD) from a demand chain management perspective. CDPD is the counterpart to typical research and development processes, which has no direct customer involvement. The proposition is that letting customers initiate and participate in the product development process...

  12. Industry-driven sector roadmaps 2020

    DEFF Research Database (Denmark)

    Ricard, Lykke Margot

    Industri-driven sector roadmaps 2020: European Technology Platforms in wind and CCS. A new corporate trend on innovation in Europe, supported by The European Commission.......Industri-driven sector roadmaps 2020: European Technology Platforms in wind and CCS. A new corporate trend on innovation in Europe, supported by The European Commission....

  13. Proton-driven plasma acceleration at CERN

    International Nuclear Information System (INIS)

    Plasma-based acceleration methods have seen important progress over the last years. Recently, it has been proposed to experimentally study plasma acceleration driven by proton beams, in addition to the established research directions of electron and laser-driven plasmas. This talk presents the planned experiment and the research efforts carried out at CERN.

  14. Rank-driven Markov processes

    CERN Document Server

    Grinfeld, Michael; Wade, Andrew R

    2011-01-01

    We study a class of Markovian systems of $N$ elements taking values in $[0,1]$ that evolve in discrete time $t$ via randomized replacement rules based on the ranks of the elements. These rank-driven processes are inspired by variants of the Bak--Sneppen model of evolution, in which the system represents an evolutionary 'fitness landscape' and which is famous as a simple model displaying self-organized criticality. Our main results are concerned with long-time large-$N$ asymptotics for the general model in which, at each time step, $K$ randomly chosen elements are discarded and replaced by independent $U[0,1]$ variables, where the ranks of the elements to be replaced are chosen, independently at each time step, according to a distribution $\\kappa_N$ on $\\{1,2,...,N\\}^K$. Our main results are that, under appropriate conditions on $\\kappa_N$, the system exhibits threshold behaviour at $s^* \\in [0,1]$, where $s^*$ is a function of $\\kappa_N$, and the marginal distribution of a randomly selected element converges ...

  15. Potential-driven Galileon inflation

    International Nuclear Information System (INIS)

    For the models of inflation driven by the potential energy of an inflaton field φ, the covariant Galileon Lagrangian (∂φ)2□φ generally works to slow down the evolution of the field. On the other hand, if the Galileon self-interaction is dominant relative to the standard kinetic term, we show that there is no oscillatory regime of inflaton after the end of inflation. This is typically accompanied by the appearance of the negative propagation speed squared cs2 of a scalar mode, which leads to the instability of small-scale perturbations. For chaotic inflation and natural inflation we clarify the parameter space in which inflaton oscillates coherently during reheating. Using the WMAP constraints of the scalar spectral index and the tensor-to-scalar ratio as well, we find that the self coupling λ of the potential V(φ) = λφ4/4 is constrained to be very much smaller than 1 and that the symmetry breaking scale f of natural inflation cannot be less than the reduced Planck mass Mpl. We also show that, in the presence of other covariant Galileon Lagrangians, there are some cases in which inflaton oscillates coherently even for the self coupling λ of the order of 0.1, but still the instability associated with negative cs2 is generally present

  16. Cosmic ray driven Galactic winds

    CERN Document Server

    Recchia, S; Morlino, G

    2016-01-01

    The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfven waves, that in turn determine the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here we investigate the launch and evolution of such winds, and we determine the impli...

  17. Cosmic-ray driven winds

    CERN Document Server

    Völk, Heinrich J

    2014-01-01

    The theory of Galactic Winds, driven by the cosmic-ray pressure gradient, is reviewed both on the magnetohydrodynamic and on the kinetic level. In this picture the magnetic field of the Galaxy above the dense gas disk is assumed to have a flux tube geometry, the flux tubes rising locally perpendicular out of the disk to become radially directed at large distances, with the cosmic-ray sources located deep within the Galactic disk. At least above the gas disk, the magnetic fluctuations which resonantly scatter the cosmic rays are selfconsistently excited as Alf{`e}n waves by the escaping cosmic rays. The fluctuation amplitudes remain finite through nonlinear wave dissipation. The spatially increasing speed of the resulting outflow results in a diffusion-convection boundary whose position depends on particle momentum. It replaces the escape boundary of static diffusion models. New effects like overall Galactic mass and angular momentum loss as well as gas heating beyond the disk appear. Also particle re-accelera...

  18. China’s industrial growth:capital-driven or resource-driven?

    Institute of Scientific and Technical Information of China (English)

    张其仔; 郭朝先

    2009-01-01

    Economic growth can take different forms;growth can be resource-driven,labor-driven,capital-driven,or technology-driven.Numerous studies conclude that China’s economic growth is capital-driven.Such a conclusion is derived after excluding any effects of resource and environmental factors.In this article,resource and environmental factors are incorporated in order to stndy the influence of factors on industrial growth.This study found that resource and environmental factors contribute much more than capital to industrial growth,and China’s industrial growth is still resource-driven.The nature of China’s industrial growth also suggests that the country’s economic growth has not completely extricated itself from a resource-driven model,which in turn exerts considerable influence on the country’s macroeconomic policies.

  19. Rank-Driven Markov Processes

    Science.gov (United States)

    Grinfeld, Michael; Knight, Philip A.; Wade, Andrew R.

    2012-01-01

    We study a class of Markovian systems of N elements taking values in [0,1] that evolve in discrete time t via randomized replacement rules based on the ranks of the elements. These rank-driven processes are inspired by variants of the Bak-Sneppen model of evolution, in which the system represents an evolutionary `fitness landscape' and which is famous as a simple model displaying self-organized criticality. Our main results are concerned with long-time large- N asymptotics for the general model in which, at each time step, K randomly chosen elements are discarded and replaced by independent U[0,1] variables, where the ranks of the elements to be replaced are chosen, independently at each time step, according to a distribution κ N on {1,2,…, N} K . Our main results are that, under appropriate conditions on κ N , the system exhibits threshold behavior at s ∗∈[0,1], where s ∗ is a function of κ N , and the marginal distribution of a randomly selected element converges to U[ s ∗,1] as t→∞ and N→∞. Of this class of models, results in the literature have previously been given for special cases only, namely the `mean-field' or `random neighbor' Bak-Sneppen model. Our proofs avoid the heuristic arguments of some of the previous work and use Foster-Lyapunov ideas. Our results extend existing results and establish their natural, more general context. We derive some more specialized results for the particular case where K=2. One of our technical tools is a result on convergence of stationary distributions for families of uniformly ergodic Markov chains on increasing state-spaces, which may be of independent interest.

  20. Laboratory blast wave driven instabilities

    Science.gov (United States)

    Kuranz, Carolyn

    2008-11-01

    This presentation discusses experiments involving the evolution of hydrodynamic instabilities in the laboratory under high-energy-density (HED) conditions. These instabilities are driven by blast waves, which occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. Instabilities evolving under HED conditions are relevant to astrophysics. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 μm plastic layer that is followed by a low-density foam layer. A blast wave structure similar to those in supernovae is created in the plastic layer. The blast wave crosses an interface having a 2D or 3D sinusoidal structure that serves as a seed perturbation for hydrodynamic instabilities. This produces unstable growth dominated by the Rayleigh-Taylor (RT) instability in the nonlinear regime. We have detected the interface structure under these conditions using x-ray backlighting. Recent advances in our diagnostic techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed or predicted by current simulations. The observed effect is potentially of great importance as a source of mass transport to places not anticipated by current theory and simulation. I will discuss the amount of mass in these spike extensions, the associated uncertainties, and hypotheses regarding their origin We also plan to show comparisons of experiments using single mode and multimode as well as 2D and 3D initial conditions. This work is sponsored by DOE/NNSA Research Grants DE-FG52-07NA28058 (Stewardship Sciences Academic Alliances) and DE-FG52-04NA00064 (National Laser User

  1. On fusion driven systems (FDS) for transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Aagren, O (Uppsala Univ., Aangstroem laboratory, div. of electricity, Uppsala (Sweden)); Moiseenko, V.E. (Inst. of Plasma Physics, National Science Center, Kharkov Inst. of Physics and Technology, Kharkov (Ukraine)); Noack, K. (Forschungszentrum Dresden-Rossendorf (Germany))

    2008-10-15

    This report gives a brief description of ongoing activities on fusion driven systems (FDS) for transmutation of the long-lived radioactive isotopes in the spent nuclear waste from fission reactors. Driven subcritical systems appears to be the only option for efficient minor actinide burning. Driven systems offer a possibility to increase reactor safety margins. A comparatively simple fusion device could be sufficient for a fusion-fission machine, and transmutation may become the first industrial application of fusion. Some alternative schemes to create strong fusion neutron fluxes are presented

  2. Optimal protocols for slowly driven quantum systems.

    Science.gov (United States)

    Zulkowski, Patrick R; DeWeese, Michael R

    2015-09-01

    The design of efficient quantum information processing will rely on optimal nonequilibrium transitions of driven quantum systems. Building on a recently developed geometric framework for computing optimal protocols for classical systems driven in finite time, we construct a general framework for optimizing the average information entropy for driven quantum systems. Geodesics on the parameter manifold endowed with a positive semidefinite metric correspond to protocols that minimize the average information entropy production in finite time. We use this framework to explicitly compute the optimal entropy production for a simple two-state quantum system coupled to a heat bath of bosonic oscillators, which has applications to quantum annealing. PMID:26465432

  3. Distributed simulation a model driven engineering approach

    CERN Document Server

    Topçu, Okan; Oğuztüzün, Halit; Yilmaz, Levent

    2016-01-01

    Backed by substantive case studies, the novel approach to software engineering for distributed simulation outlined in this text demonstrates the potent synergies between model-driven techniques, simulation, intelligent agents, and computer systems development.

  4. Automated Testing of Event-Driven Applications

    DEFF Research Database (Denmark)

    Jensen, Casper Svenning

    may be tested by selecting an interesting input (i.e. a sequence of events), and deciding if a failure occurs when the selected input is applied to the event-driven application under test. Automated testing promises to reduce the workload for developers by automatically selecting interesting inputs...... and detect failures. However, it is non-trivial to conduct automated testing of event-driven applications because of, for example, infinite input spaces and the absence of specifications of correct application behavior. In this PhD dissertation, we identify a number of specific challenges when conducting...... automated testing of event-driven applications, and we present novel techniques for solving these challenges. First, we present an algorithm for stateless model-checking of event-driven applications with partial-order reduction, and we show how this algorithm may be used to systematically test web...

  5. Test-driven development with Django

    CERN Document Server

    Harvey, Kevin

    2015-01-01

    This book is for Django developers with little or no knowledge of test-driven development or testing in general. Familiarity with the command line, setting up a Python virtual environment, and starting a Django project are assumed.

  6. Graphical querying of model-driven spreadsheets

    OpenAIRE

    Cunha, Jácome Miguel Costa; Fernandes, João Paulo de Sousa Ferreira; Pereira, Rui Alexandre Afonso; Saraiva, João Alexandre

    2014-01-01

    This paper presents a graphical interface to query modeldriven spreadsheets, based on experience with previous work and empirical studies in querying systems, to simplify query construction for typical end-users with little to no knowledge of SQL. We briefly show our previous text based model-driven querying system. Afterwards, we detail our graphical model-driven querying interface, explaining each part of the interface and showing an example. To validate our work, we executed an empirica...

  7. Creating a performance-driven system

    OpenAIRE

    Rudy Crew

    1998-01-01

    The New York City public school system is in the process of creating the nation's first performance-driven system. Such a system promotes competition, maintains quality, and emphasizes a consistently high level of achievement. The goal of a performance-driven system is to set clear standards and to align resources, policies, and practices with the support that students need to hit the target. The following management principles are used at all levels of the organization: define clear standard...

  8. A Micropump Driven by Marangoni Effect

    Science.gov (United States)

    Sugimoto, Kenji; Iwamoto, Kaoru; Kawamura, Hiroshi

    A micropump driven by the thermocapillary convection is proposed. The purpose of this study is to examine the flow structure in liquid region and the effect of the geometry on the performance of the present micropump. There are two significant advantages in the thermocapillary-driven system. First, the surface forces become more dominant than the volume forces with decreasing scale. The present micropump driven by the surface forces shows an advantage in the micro scale over a diaphragm pump driven by the volume forces. Secondary, the thermocapillary driven system contains no movable parts; thus, it allows a very simple structure compared to the diaphragm one. In the present micropump system, a number of ribs are distributed along the flow circuit between a heater and a cooler. Since heat transfer from these ribs to the working liquid imposes temperature gradients along the gas-liquid interfaces, the flow from the hot to the cold side is induced by the Marangoni effect. Fundamental characteristics of the present micropump are studied on the basis of three-dimensional simulation conducted taking the gas, liquid and ribs into account. In this study, the flow structure corresponding to the temperature field was observed. The present calculation has revealed that the flow field exhibits a transition from steady flow to oscillatory flow when the Marangoni number exceeds a critical value of about 2,000-2,500. An experiment was also performed. The liquid flow driven by the present micropump system was confirmed through the experiment.

  9. Glassy dynamics of driven elastic manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Vinokur, V.M.

    1996-12-31

    We study the low-temperature dynamics of an elastic manifold driven through a random medium. For driving forces well below the zero- temperature depinning force, the manifold advances via thermally activated hops over the energy barriers separating favorable metastable states. We develop a scaling theory of the thermally activated dynamics (creep) and find a nonlinear glassy response for the driven manifold, {upsilon}{approximately}exp(-const{times}F{sup - {mu}}). We consider an exactly solvable 1-D model for random driven dynamics which exhibits a creep-like velocity-force characteristic. We discuss a microscopic mechanism for the creep motion and show that the distribution of waiting times for the hopping processes scales as a power law. This power-law distribution naturally yields an exponential response for the creep of the manifold.

  10. Terahertz-driven linear electron acceleration

    CERN Document Server

    Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2014-01-01

    The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

  11. Test-driven modeling of embedded systems

    DEFF Research Database (Denmark)

    Munck, Allan; Madsen, Jan

    2015-01-01

    To benefit maximally from model-based systems engineering (MBSE) trustworthy high quality models are required. From the software disciplines it is known that test-driven development (TDD) can significantly increase the quality of the products. Using a test-driven approach with MBSE may have...... a similar positive effect on the quality of the system models and the resulting products and may therefore be desirable. To define a test-driven model-based systems engineering (TD-MBSE) approach, we must define this approach for numerous sub disciplines such as modeling of requirements, use cases...... suggest that our method provides a sound foundation for rapid development of high quality system models....

  12. Metamodel-Driven Evolution with Grammar Inference

    Science.gov (United States)

    Bryant, Barrett R.; Liu, Qichao; Mernik, Marjan

    2010-10-01

    Domain-specific modeling (DSM) has become one of the most popular techniques for incorporating model-driven engineering (MDE) into software engineering. In DSM, domain experts define metamodels to describe the essential problems in a domain. A model conforms to a schema definition represented by a metamodel in a similar manner to a programming language conforms to a grammar. Metamodel-driven evolution is when a metamodel undergoes evolutions to incorporate new concerns in the domain. However, this results in losing the ability to use existing model instances. Grammar inference is the problem of inferring a grammar from sample strings which the grammar should generate. This paper describes our work in solving the problem of metamodel-driven evolution with grammar inference, by inferring the metamodel from model instances.

  13. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

    Bykov, A M; Malkov, M A; Osipov, S M

    2013-01-01

    Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

  14. Light-field driven currents in graphene

    CERN Document Server

    Higuchi, Takuya; Ullmann, Konrad; Weber, Heiko B; Hommelhoff, Peter

    2016-01-01

    Ultrafast electron dynamics in solids under strong optical fields has recently found particular attention. In dielectrics and semiconductors, various light-field-driven effects have been explored, such as high-harmonic generation, sub-optical-cycle interband population transfer and nonperturbative increase of transient polarizability. In contrast, much less is known about field-driven electron dynamics in metals because charge carriers screen an external electric field in ordinary metals. Here we show that atomically thin monolayer Graphene offers unique opportunities to study light-field-driven processes in a metal. With a comparably modest field strength of up to 0.3 V/{\\AA}, we drive combined interband and intraband electron dynamics, leading to a light-field-waveform controlled residual conduction current after the laser pulse is gone. We identify the underlying pivotal physical mechanism as electron quantum-path interference taking place on the 1-femtosecond ($10^{-15}$ second) timescale. The process can...

  15. User Driven Innovation in the Building Process

    DEFF Research Database (Denmark)

    Christiansson, Per; Sørensen, Kristian Birch; Rødtness, Mette;

    2008-01-01

    Innovation in Construction (VIC) project. One important driving force for change is the opportunity for users to develop and articulate real needs concerning for example different functionalities of a building and its parts, but also on artifacts supporting the actual needs capture and requirements...... to introduction of advanced information and communication technology (ICT). The paper focuses on creative changes of the building process powered by user driven innovation activities. An overview of existing user driven innovation methodologies is given as well experiences from the ongoing Virtual...... formulation during building design. A general methodological framework and meta ontology for Virtual Innovation in Construction is presented as well as findings from implementation of the method....

  16. Domain Driven Data Mining - Application to Business

    Directory of Open Access Journals (Sweden)

    Adeyemi Adejuwon

    2010-07-01

    Full Text Available Conventional data mining applications face serious difficulties in solving complex real-life business decision making problems when practically deployed. This work in order to improve the operations in a collection of business domains aims to suggest solutions by reviewing and studying the latest methodological, technical, practical progresses and some cases studies of data mining via domain driven data mining (DDDM. The presented paper tries to answer this question: "what can domain driven data mining do for real-life business applications?" Moreover this work attempts to provide information and abilities to fill the existing gap between academic researches and real-world business problems.

  17. Semantic Web and Model-Driven Engineering

    CERN Document Server

    Parreiras, Fernando S

    2012-01-01

    The next enterprise computing era will rely on the synergy between both technologies: semantic web and model-driven software development (MDSD). The semantic web organizes system knowledge in conceptual domains according to its meaning. It addresses various enterprise computing needs by identifying, abstracting and rationalizing commonalities, and checking for inconsistencies across system specifications. On the other side, model-driven software development is closing the gap among business requirements, designs and executables by using domain-specific languages with custom-built syntax and se

  18. Developments in laser-driven plasma accelerators

    CERN Document Server

    Hooker, Simon Martin

    2014-01-01

    Laser-driven plasma accelerators provide acceleration gradients three orders of magnitude greater than conventional machines, offering the potential to shrink the length of accelerators by the same factor. To date, laser-acceleration of electron beams to particle energies comparable to those offered by synchrotron light sources has been demonstrated with plasma acceleration stages only a few centimetres long. This article describes the principles of operation of laser-driven plasma accelerators, and reviews their development from their proposal in 1979 to recent demonstrations. The potential applications of plasma accelerators are described and the challenges which must be overcome before they can become a practical tool are discussed.

  19. Test and Behaviour Driven Development with Python

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Experience has taught us that bugs are impossible to avoid when programming. Specially on continuous delivery processes where there are new versions that refactor or incorporate new modules to the project. Although, there are different tools which help us to ensure code quality by enabling developers to catch bugs while still in the development stage. In this talk, I will talk about Test-driven development(TDD) and Behaviour-Driven development (BDD) methodologies focused on web development. Also, I will present an overview of unit testing tools as Selenium or Behave, which help us to produce working software, with fewer bugs, quickly and consistently.

  20. Test-driven development with Mockito

    CERN Document Server

    Acharya, Sujoy

    2013-01-01

    This book is a hands-on guide, full of practical examples to illustrate the concepts of Test Driven Development.If you are a developer who wants to develop software following Test Driven Development using Mockito and leveraging various Mockito features, this book is ideal for you. You don't need prior knowledge of TDD, Mockito, or JUnit.It is ideal for developers, who have some experience in Java application development as well as a basic knowledge of unit testing, but it covers the basic fundamentals of TDD and JUnit testing to get you acquainted with these concepts before delving into them.

  1. WIND DRIVEN MOBILE CHARGING OF AUTOMOBILE BATTERY

    Directory of Open Access Journals (Sweden)

    SUDHIR KUMAR SINHA

    2011-01-01

    Full Text Available This paper deals with implementation of mobile wind driven generator technology to produce electricity in charging of two wheeler (12V automobile battery. The use of PWM methodology with pulse charging method at a constant rate has been adopted for this purpose. The low speed PMSG driven by wind at speed of 15/40 km/hour has been used to eliminate gear box to achieve high efficiency. The output of three phase bridge rectifier is fed to boost converter which provides pulses of constant current to the battery.

  2. Dynamical Behavior of the Driven Morse Oscillator

    Institute of Scientific and Technical Information of China (English)

    郭荣伟; 黄德斌; 张立震

    2003-01-01

    The dynamics of the driven Morse oscillator describing the photo dissociation of Molecules in theoretical chemistry was qualitatively studied. Firstly the suhharmonic Melnikov method was used to prove the existence of periodic orbits in this model. Further it was rigorously proved that this model has chaotic dynamics in the sense of Smale horseshoes by introducing the famous McGehee transformation and applying the homoclinic Melnikov method. The obtained results give an analytic demonstration of the previous numerical results, that is, the driven Morse oscillator admits stochastic excitation and dissociation associated with the onset of chaos.

  3. Scripted Bodies and Spline Driven Animation

    DEFF Research Database (Denmark)

    Erleben, Kenny; Henriksen, Knud

    2002-01-01

    In this paper we will take a close look at the details and technicalities in applying spline driven animation to scripted bodies in the context of dynamic simulation. The main contributions presented in this paper are methods for computing velocities and accelerations in the time domain of the sp......In this paper we will take a close look at the details and technicalities in applying spline driven animation to scripted bodies in the context of dynamic simulation. The main contributions presented in this paper are methods for computing velocities and accelerations in the time domain...

  4. Work in the Knowledge-Driven Economy.

    Science.gov (United States)

    Bayliss, Valerie

    2001-01-01

    The knowledge-driven economy has become a "given," yet there is disagreement over what it entails and who is helped or harmed. The aging of the work force, disappearance of unskilled jobs, and changes in business and social organization suggest that the social, economic, and infrastructural problems of the knowledge economy will not solve…

  5. Failure-probability driven dose painting

    DEFF Research Database (Denmark)

    Vogelius, Ivan R; Håkansson, Katrin; Due, Anne K;

    2013-01-01

    To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning stu...

  6. Light-driven cytochrome P450 hydroxylations

    DEFF Research Database (Denmark)

    Jensen, Kenneth; Jensen, Poul Erik; Møller, Birger Lindberg

    2011-01-01

    Plants are light-driven "green" factories able to synthesize more than 200,000 different bioactive natural products, many of which are high-value products used as drugs (e.g., artemisinin, taxol, and thapsigargin). In the formation of natural products, cytochrome P450 (P450) monooxygenases play...

  7. Quantitative system validation in model driven design

    DEFF Research Database (Denmark)

    Hermanns, Hilger; Larsen, Kim Guldstrand; Raskin, Jean-Francois;

    2010-01-01

    The European STREP project Quasimodo1 develops theory, techniques and tool components for handling quantitative constraints in model-driven development of real-time embedded systems, covering in particular real-time, hybrid and stochastic aspects. This tutorial highlights the advances made, focus...

  8. Data-driven regionalization of housing markets

    NARCIS (Netherlands)

    Helbich, M.; Brunauer, W.; Hagenauer, J.; Leitner, M.

    2013-01-01

    This article presents a data-driven framework for housing market segmentation. Local marginal house price surfaces are investigated by means of mixed geographically weighted regression and are reduced to a set of principal component maps, which in turn serve as input for spatial regionalization. The

  9. Solar driven membrane pervaporation for desalination processes

    NARCIS (Netherlands)

    Zwijnenberg, H.J.; Koops, G.H.; Wessling, M.

    2005-01-01

    We describe details of a solar driven pervaporation process for the production of desalinated water from highly contaminated waters. The membrane material is a polyetheramide-based polymer film of 40 ¿m thickness. This Solar Dew® membrane is used in a tubular configuration in a direct solar membrane

  10. Direct Numerical Simulation of Driven Cavity Flows

    NARCIS (Netherlands)

    Verstappen, R.; Wissink, J.G.; Veldman, A.E.P.

    1993-01-01

    Direct numerical simulations of 2D driven cavity flows have been performed. The simulations exhibit that the flow converges to a periodically oscillating state at Re=11,000, and reveal that the dynamics is chaotic at Re=22,000. The dimension of the attractor and the Kolmogorov entropy have been comp

  11. Light-driven robotics for nanoscopy

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    2013-01-01

    The science fiction inspired shrinking of macro-scale robotic manipulation and handling down to the micro- and nanoscale regime opens new doors for exploiting the forces and torques of light for micro- and nanoscopic probing, actuation and control. Advancing light-driven micro-robotics requires...... and matter for robotically probing at the smallest biological length scales....

  12. Using Two Different Approaches to Assess Dietary Patterns: Hypothesis-Driven and Data-Driven Analysis

    Directory of Open Access Journals (Sweden)

    Ágatha Nogueira Previdelli

    2016-09-01

    Full Text Available The use of dietary patterns to assess dietary intake has become increasingly common in nutritional epidemiology studies due to the complexity and multidimensionality of the diet. Currently, two main approaches have been widely used to assess dietary patterns: data-driven and hypothesis-driven analysis. Since the methods explore different angles of dietary intake, using both approaches simultaneously might yield complementary and useful information; thus, we aimed to use both approaches to gain knowledge of adolescents’ dietary patterns. Food intake from a cross-sectional survey with 295 adolescents was assessed by 24 h dietary recall (24HR. In hypothesis-driven analysis, based on the American National Cancer Institute method, the usual intake of Brazilian Healthy Eating Index Revised components were estimated. In the data-driven approach, the usual intake of foods/food groups was estimated by the Multiple Source Method. In the results, hypothesis-driven analysis showed low scores for Whole grains, Total vegetables, Total fruit and Whole fruits, while, in data-driven analysis, fruits and whole grains were not presented in any pattern. High intakes of sodium, fats and sugars were observed in hypothesis-driven analysis with low total scores for Sodium, Saturated fat and SoFAA (calories from solid fat, alcohol and added sugar components in agreement, while the data-driven approach showed the intake of several foods/food groups rich in these nutrients, such as butter/margarine, cookies, chocolate powder, whole milk, cheese, processed meat/cold cuts and candies. In this study, using both approaches at the same time provided consistent and complementary information with regard to assessing the overall dietary habits that will be important in order to drive public health programs, and improve their efficiency to monitor and evaluate the dietary patterns of populations.

  13. Using Two Different Approaches to Assess Dietary Patterns: Hypothesis-Driven and Data-Driven Analysis.

    Science.gov (United States)

    Previdelli, Ágatha Nogueira; de Andrade, Samantha Caesar; Fisberg, Regina Mara; Marchioni, Dirce Maria

    2016-01-01

    The use of dietary patterns to assess dietary intake has become increasingly common in nutritional epidemiology studies due to the complexity and multidimensionality of the diet. Currently, two main approaches have been widely used to assess dietary patterns: data-driven and hypothesis-driven analysis. Since the methods explore different angles of dietary intake, using both approaches simultaneously might yield complementary and useful information; thus, we aimed to use both approaches to gain knowledge of adolescents' dietary patterns. Food intake from a cross-sectional survey with 295 adolescents was assessed by 24 h dietary recall (24HR). In hypothesis-driven analysis, based on the American National Cancer Institute method, the usual intake of Brazilian Healthy Eating Index Revised components were estimated. In the data-driven approach, the usual intake of foods/food groups was estimated by the Multiple Source Method. In the results, hypothesis-driven analysis showed low scores for Whole grains, Total vegetables, Total fruit and Whole fruits), while, in data-driven analysis, fruits and whole grains were not presented in any pattern. High intakes of sodium, fats and sugars were observed in hypothesis-driven analysis with low total scores for Sodium, Saturated fat and SoFAA (calories from solid fat, alcohol and added sugar) components in agreement, while the data-driven approach showed the intake of several foods/food groups rich in these nutrients, such as butter/margarine, cookies, chocolate powder, whole milk, cheese, processed meat/cold cuts and candies. In this study, using both approaches at the same time provided consistent and complementary information with regard to assessing the overall dietary habits that will be important in order to drive public health programs, and improve their efficiency to monitor and evaluate the dietary patterns of populations. PMID:27669289

  14. Using Two Different Approaches to Assess Dietary Patterns: Hypothesis-Driven and Data-Driven Analysis.

    Science.gov (United States)

    Previdelli, Ágatha Nogueira; de Andrade, Samantha Caesar; Fisberg, Regina Mara; Marchioni, Dirce Maria

    2016-09-23

    The use of dietary patterns to assess dietary intake has become increasingly common in nutritional epidemiology studies due to the complexity and multidimensionality of the diet. Currently, two main approaches have been widely used to assess dietary patterns: data-driven and hypothesis-driven analysis. Since the methods explore different angles of dietary intake, using both approaches simultaneously might yield complementary and useful information; thus, we aimed to use both approaches to gain knowledge of adolescents' dietary patterns. Food intake from a cross-sectional survey with 295 adolescents was assessed by 24 h dietary recall (24HR). In hypothesis-driven analysis, based on the American National Cancer Institute method, the usual intake of Brazilian Healthy Eating Index Revised components were estimated. In the data-driven approach, the usual intake of foods/food groups was estimated by the Multiple Source Method. In the results, hypothesis-driven analysis showed low scores for Whole grains, Total vegetables, Total fruit and Whole fruits), while, in data-driven analysis, fruits and whole grains were not presented in any pattern. High intakes of sodium, fats and sugars were observed in hypothesis-driven analysis with low total scores for Sodium, Saturated fat and SoFAA (calories from solid fat, alcohol and added sugar) components in agreement, while the data-driven approach showed the intake of several foods/food groups rich in these nutrients, such as butter/margarine, cookies, chocolate powder, whole milk, cheese, processed meat/cold cuts and candies. In this study, using both approaches at the same time provided consistent and complementary information with regard to assessing the overall dietary habits that will be important in order to drive public health programs, and improve their efficiency to monitor and evaluate the dietary patterns of populations.

  15. A Science Model Driven Retrieval Prototype

    CERN Document Server

    Mayr, Philipp; Mutschke, Peter

    2011-01-01

    This paper is about a better understanding on the structure and dynamics of science and the usage of these insights for compensating the typical problems that arises in metadata-driven Digital Libraries. Three science model driven retrieval services are presented: co-word analysis based query expansion, re-ranking via Bradfordizing and author centrality. The services are evaluated with relevance assessments from which two important implications emerge: (1) precision values of the retrieval service are the same or better than the tf-idf retrieval baseline and (2) each service retrieved a disjoint set of documents. The different services each favor quite other - but still relevant - documents than pure term-frequency based rankings. The proposed models and derived retrieval services therefore open up new viewpoints on the scientific knowledge space and provide an alternative framework to structure scholarly information systems.

  16. Patient safety and technology-driven medication

    DEFF Research Database (Denmark)

    Orbæk, Janne; Gaard, Mette; Keinicke Fabricius, Pia;

    2015-01-01

    BACKGROUND: The technology-driven medication process is complex, involving advanced technologies, patient participation and increased safety measures. Medication administration errors are frequently reported, with nurses implicated in 26-38% of in-hospital cases. This points to the need for new......, transcribed and analyzed using the systematic horizontal phenomenological-hermeneutic template methodology. RESULTS: The interviews uncovered that understanding the technologies; professionalism and patient safety are three crucial elements in the medication process. The students expressed positivity...... ways of educating nursing students in today's medication administration. AIM: To explore nursing students' experiences and competences with the technology-driven medication administration process. METHODS: 16 pre-graduate nursing students were included in two focus group interviews which were recorded...

  17. Strongly driven spin rotations in diamond

    International Nuclear Information System (INIS)

    We present in this talk theoretical background, numerical simulations and experimental evidences of strongly driven single spin rotations through the application of optimal control methods. The spin, an electron spin of the nitrogen-vacancy colour centre in diamond, is strongly driven by a numerically optimised microwave (MW) control. To obtain such control we employ a quantum optimal control method, namely chopped random basis (CRAB) algorithm. We show that arbitrary spin rotations are possible by demonstrating pi and half-pi spin rotations without resorting to the common rotating-wave-approximation (RWA). Furthermore, the rotations are performed faster than that of the RWA-Rabi oscillation at the same MW amplitude, and they are more robust to magnetic field noise than those based on bang-bang control. These results are promising to increase the number of operations in quantum computer before decoherence take place and can improve the performance of diamond-based quantum technologies. (author)

  18. Quality of Data Driven Simulation Workflows

    Directory of Open Access Journals (Sweden)

    Michael Reiter

    2014-01-01

    Full Text Available Simulations are long-running computations driven by non-trivial data dependencies. Workflow technology helps to automate these simulations and enable using Quality of Data (QoD frameworks to determine the goodness of simulation data. However, existing frameworks are specific to scientific domains, individual applications, or proprietary workflow engine extensions. In this paper, we propose a generic approach to use QoD as a uniform means to steer complex interdisciplinary simulations implemented as workflows. The approach enables scientists to specify abstract QoD requirements that are considered to steer the workflow for ensuring a precise final result. To realize these Quality of Data-driven workflows, we present a middleware architecture and a WS-Policy-based language to describe QoD requirements and capabilities. To prove technical feasibility, we present a prototype for controlling and steering simulation workflows and a real world simulation scenario.

  19. Shape-Driven Nested Markov Tessellations

    CERN Document Server

    Schreiber, Tomasz

    2011-01-01

    A new and rather broad class of stationary (i.e. stochastically translation invariant) random tessellations of the $d$-dimensional Euclidean space is introduced, which are called shape-driven nested Markov tessellations. Locally, these tessellations are constructed by means of a spatio-temporal random recursive split dynamics governed by a family of Markovian split kernel, generalizing thereby the -- by now classical -- construction of iteration stable random tessellations. By providing an explicit global construction of the tessellations, it is shown that under suitable assumptions on the split kernels (shape-driven), there exists a unique time-consistent whole-space tessellation-valued Markov process of stationary random tessellations compatible with the given split kernels. Beside the existence and uniqueness result, the typical cell and some aspects of the first-order geometry of these tessellations are in the focus of our discussion.

  20. A charge-driven molecular water pump.

    Science.gov (United States)

    Gong, Xiaojing; Li, Jingyuan; Lu, Hangjun; Wan, Rongzheng; Li, Jichen; Hu, Jun; Fang, Haiping

    2007-11-01

    Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications, including the desalination of seawater. Nanopumps driven by electric or magnetic fields can transport ions and magnetic quanta, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient. PMID:18654410

  1. Mastering Technologies in Design-Driven Innovation

    DEFF Research Database (Denmark)

    Dell'era, Claudio; Marchesi, Alessio; Verganti, Roberto

    2010-01-01

    Only a few companies have mastered the design-driven approach to innovation. This paper examines what it means to make design a central part of the business process, able to add value to products and create new markets. More specifically, it focuses on the interplay between the functional...... and semantic dimensions of a product. Case studies of two leading Italian companies in the furniture industry--Kartell and Luceplan--illustrate two principal interpretations of the role of technology in radical design-driven innovation: technology as an enabler of new product meanings for the customer......, and the importance of supply networks that allow manufacturers to change product technologies quickly and experiment with new technologies....

  2. Hydrodynamic synchronisation of optically driven rotors

    Science.gov (United States)

    Debono, Luke J.; Box, Stuart; Phillips, David B.; Simpson, Stephen H.; Hanna, Simon

    2015-08-01

    Hydrodynamic coupling is thought to play a role in the coordinated beating of cilia and flagella, and may inform the future design of artificial swimmers and pumps. In this study, optical tweezers are used to investigate the hydrodynamic coupling between a pair of driven oscillators. The theoretical model of Lenz and Ryskin [P. Lenz and A. Ryskin, Phys. Biol. 3, 285{294 (2006)] is experimentally recreated, in which each oscillator consists of a sphere driven in a circular trajectory. The optical trap position is maintained ahead of the sphere to provide a tangential driving force. The trap is also moved radially to harmonically constrain the sphere to the circular trajectory. Analytically, it has been shown that two oscillators of this type are able to synchronise or phase-lock under certain conditions. We explore the interplay between synchronisation mechanisms and find good agreement between experiment, theory and Brownian dynamics simulations.

  3. Model Driven Development of Data Sensitive Systems

    DEFF Research Database (Denmark)

    Olsen, Petur

    2014-01-01

    Model-driven development strives to use formal artifacts during the development process. Formal artifacts enables automatic analyses of some aspects of the system under development. This serves to increase the understanding of the (intended) behavior of the system as well as increasing error...... to the values of variables. This theses strives to improve model-driven development of such data-sensitive systems. This is done by addressing three research questions. In the first we combine state-based modeling and abstract interpretation, in order to ease modeling of data-sensitive systems, while allowing...... efficient model-checking and model-based testing. In the second we develop automatic abstraction learning used together with model learning, in order to allow fully automatic learning of data-sensitive systems to allow learning of larger systems. In the third we develop an approach for modeling and model...

  4. Data Driven Constraints for the SVM

    DEFF Research Database (Denmark)

    Darkner, Sune; Clemmensen, Line Katrine Harder

    2012-01-01

    We propose a generalized data driven constraint for support vector machines exemplified by classification of paired observations in general and specifically on the human ear canal. This is particularly interesting in dynamic cases such as tissue movement or pathologies developing over time....... Assuming that two observations of the same subject in different states span a vector, we hypothesise that such structure of the data contains implicit information which can aid the classification, thus the name data driven constraints. We derive a constraint based on the data which allow for the use...... classifier solution, compared to the SVM i.e. reduces variance and improves classification rates. We present a quantitative measure of the information level contained in the pairing and test the method on simulated as well as a high-dimensional paired data set of ear-canal surfaces....

  5. Electrically Driven Spin Dynamics of Paramagnetic Impurities

    Science.gov (United States)

    Saha, D.; Siddiqui, L.; Bhattacharya, P.; Datta, S.; Basu, D.; Holub, M.

    2008-05-01

    The spin dynamics of dilute paramagnetic impurities embedded in a semiconductor GaAs channel of a conventional lateral spin valve has been investigated. It is observed that the electron spin of paramagnetic Mn atoms can be polarized electrically when driven by a spin valve in the antiparallel configuration. The transient current through the MnAs/GaAs/MnAs spin valve bears the signature of the underlying spin dynamics driven by the exchange interaction between the conduction band electrons in GaAs and the localized Mn electron spins. The time constant for this interaction is observed to be dependent on temperature and is estimated to be 80 ns at 15 K.

  6. Stable transport in proton driven Fast Ignition

    CERN Document Server

    Bret, A

    2009-01-01

    Proton beam transport in the context of proton driven Fast Ignition is usually assumed to be stable due to protons high inertia, but an analytical analysis of the process is still lacking. The stability of a charge and current neutralized proton beam passing through a plasma is therefore conducted here, for typical proton driven Fast Ignition parameters. In the cold regime, two fast growing Buneman-like modes are found, with an inverse growth-rate much smaller than the beam time-of-flight to the target core. The stability issue is thus not so obvious, and Kinetic effects are investigated. One unstable mode is found stabilized by the background plasma protons and electrons temperatures. The second mode is also damped, providing the proton beam thermal spread is larger than $\\sim$ 10 keV. In Fusion conditions, the beam propagation should therefore be stable.

  7. User driven innovation in mobile technologies?

    DEFF Research Database (Denmark)

    Larsen, Casper Schultz; Koch, Christian

    2007-01-01

    Developing dedicated mobile technology systems for AEC demands the introduction of user driven innovation. A Danish research project collected international examples and user-experiences of mobile and handheld ICT in the building industry i.a. by reading off the functionality of the mobile...... technology systems relying on the concept of affordance. This paper examines how innovation processes mediate between user orientations and technology offers. There is a great potential for mobile handheld ICT-systems to support numerous work processes in the AEC-industry and this can be substantiated...... by systems already in function. Stories of prior business successes can be an important tool to ensure further innovative investments since lack of enterprise strategies is often an obstacle for innovation, especially user driven. Both small and large software houses develops dedicated software for coupling...

  8. A Model-Driven Probabilistic Parser Generator

    CERN Document Server

    Quesada, Luis; Cortijo, Francisco J

    2012-01-01

    Existing probabilistic scanners and parsers impose hard constraints on the way lexical and syntactic ambiguities can be resolved. Furthermore, traditional grammar-based parsing tools are limited in the mechanisms they allow for taking context into account. In this paper, we propose a model-driven tool that allows for statistical language models with arbitrary probability estimators. Our work on model-driven probabilistic parsing is built on top of ModelCC, a model-based parser generator, and enables the probabilistic interpretation and resolution of anaphoric, cataphoric, and recursive references in the disambiguation of abstract syntax graphs. In order to prove the expression power of ModelCC, we describe the design of a general-purpose natural language parser.

  9. Noise-driven phenomena in hysteretic systems

    CERN Document Server

    Dimian, Mihai

    2014-01-01

    Noise-Driven Phenomena in Hysteretic Systems provides a general approach to nonlinear systems with hysteresis driven by noisy inputs, which leads to a unitary framework for the analysis of various stochastic aspects of hysteresis. This book includes integral, differential and algebraic models that are used to describe scalar and vector hysteretic nonlinearities originating from various areas of science and engineering. The universality of the authors approach is also reflected by the diversity of the models used to portray the input noise, from the classical Gaussian white noise to its impulsive forms, often encountered in economics and biological systems, and pink noise, ubiquitous in multi-stable electronic systems. The book is accompanied by HysterSoft© - a robust simulation environment designed to perform complex hysteresis modeling – that can be used by the reader to reproduce many of the results presented in the book as well as to research both disruptive and constructive effects of noise in hysteret...

  10. Building Test Cases through Model Driven Engineering

    Science.gov (United States)

    Sousa, Helaine; Lopes, Denivaldo; Abdelouahab, Zair; Hammoudi, Slimane; Claro, Daniela Barreiro

    Recently, Model Driven Engineering (MDE) has been proposed to face the complexity in the development, maintenance and evolution of large and distributed software systems. Model Driven Architecture (MDA) is an example of MDE. In this context, model transformations enable a large reuse of software systems through the transformation of a Platform Independent Model into a Platform Specific Model. Although source code can be generated from models, defects can be injected during the modeling or transformation process. In order to delivery software systems without defects that cause errors and fails, the source code must be submitted to test. In this paper, we present an approach that takes care of test in the whole software life cycle, i.e. it starts in the modeling level and finishes in the test of source code of software systems. We provide an example to illustrate our approach.

  11. Tuned, driven, and active soft matter

    OpenAIRE

    Menzel, Andreas M.

    2015-01-01

    One characteristic feature of soft matter systems is their strong response to external stimuli. As a consequence they are comparatively easily driven out of their ground state and out of equilibrium, which leads to many of their fascinating properties. Here, we review illustrative examples. This review is structured by an increasing distance from the equilibrium ground state. On each level, examples of increasing degree of complexity are considered. In detail, we first consider systems that a...

  12. Tuned, driven, and active soft matter

    Science.gov (United States)

    Menzel, Andreas M.

    2015-02-01

    One characteristic feature of soft matter systems is their strong response to external stimuli. As a consequence they are comparatively easily driven out of their ground state and out of equilibrium, which leads to many of their fascinating properties. Here, we review illustrative examples. This review is structured by an increasing distance from the equilibrium ground state. On each level, examples of increasing degree of complexity are considered. In detail, we first consider systems that are quasi-statically tuned or switched to a new state by applying external fields. These are common liquid crystals, liquid crystalline elastomers, or ferrogels and magnetic elastomers. Next, we concentrate on systems steadily driven from outside e.g. by an imposed flow field. In our case, we review the reaction of nematic liquid crystals, of bulk-filling periodically modulated structures such as block copolymers, and of localized vesicular objects to an imposed shear flow. Finally, we focus on systems that are "active" and "self-driven". Here our range spans from idealized self-propelled point particles, via sterically interacting particles like granular hoppers, via microswimmers such as self-phoretically driven artificial Janus particles or biological microorganisms, via deformable self-propelled particles like droplets, up to the collective behavior of insects, fish, and birds. As we emphasize, similarities emerge in the features and behavior of systems that at first glance may not necessarily appear related. We thus hope that our overview will further stimulate the search for basic unifying principles underlying the physics of these soft materials out of their equilibrium ground state.

  13. Software engineering architecture-driven software development

    CERN Document Server

    Schmidt, Richard F

    2013-01-01

    Software Engineering: Architecture-driven Software Development is the first comprehensive guide to the underlying skills embodied in the IEEE's Software Engineering Body of Knowledge (SWEBOK) standard. Standards expert Richard Schmidt explains the traditional software engineering practices recognized for developing projects for government or corporate systems. Software engineering education often lacks standardization, with many institutions focusing on implementation rather than design as it impacts product architecture. Many graduates join the workforce with incomplete skil

  14. An Assembler Driven Verification Methodology (ADVM)

    OpenAIRE

    Macbeth, John S.; Heinz, Dietmar; Gray, Ken

    2005-01-01

    Submitted on behalf of EDAA (http://www.edaa.com/) International audience This paper presents an overview of an assembler driven verification methodology (ADVM) that was created and implemented for a chip card project at Infineon Technologies AG. The primary advantage of this methodology is that it enables rapid porting of directed tests to new targets and derivatives, with only a minimum amount of code refactoring. As a consequence, considerable verification development time and effort...

  15. Scaling the electromagnetically driven explosive shock simulator

    Science.gov (United States)

    Persh, Robert I.

    1987-01-01

    A heavy payload electromagnetically driven explosive shock simulator, referred to as EDESS-3, has been assembled and characterized at the Navel research Weapons Center. EDESS-3 is the logical outgrowth of the earlier EDESS 1 and 2 simulator work which explored the use of electrical pulse power technology for the generation of explosive like shocks. The features of the EDESS-3 are presented, and designs for the next generation of EDESS machines are introduced.

  16. Is Earthquake Triggering Driven by Small Earthquakes?

    OpenAIRE

    Helmstetter, Agnes

    2002-01-01

    Using a catalog of seismicity for Southern California, we measure how the number of triggered earthquakes increases with the earthquake magnitude. The trade-off between this relation and the distribution of earthquake magnitudes controls the relative role of small compared to large earthquakes. We show that seismicity triggering is driven by the smallest earthquakes, which trigger fewer events than larger earthquakes, but which are much more numerous. We propose that the non-trivial scaling o...

  17. A User Driven Dynamic Circuit Network Implementation

    OpenAIRE

    Guok, Chin

    2009-01-01

    The requirements for network predictability are becoming increasingly critical to the DoE science community where resources are widely distributed and collaborations are world-wide. To accommodate these emerging requirements, the Energy Sciences Network has established a Science Data Network to provide user driven guaranteed bandwidth allocations. In this paper we outline the design, implementation, and secure coordinated use of such a network, as well as some lessons learned.

  18. Functional resilience against climate-driven extinctions

    OpenAIRE

    Liebergesell, Mario; Reu, Björn; Stahl, Ulrike; Freiberg, Martin; Welk, Erik; Kattge, Jens; Cornelissen, J. Hans C.; Peñuelas, Josep

    2016-01-01

    Future global change scenarios predict a dramatic loss of biodiversity for many regions in the world, potentially reducing the resistance and resilience of ecosystem functions. Once before, during Plio-Pleistocene glaciations, harsher climatic conditions in Europe as compared to North America led to a more depauperate tree flora. Here we hypothesize that this climate driven species loss has also reduced functional diversity in Europe as compared to North America. We used variation in 26 trait...

  19. Parametrically Driven Nonlinear Oscillators with an Impurity

    Institute of Scientific and Technical Information of China (English)

    张卓; 唐翌

    2002-01-01

    By virtue of the method of multiple scales, we study a chain of parametrically driven nonlinear oscillators with a mass impurity. An equation is presented to describe the nonlinear wave of small amplitude in the chain.In our derivation, the equation is applicable to any eigenmode of coupled pendulum. Our result shows that a nonpropagation soliton emerges as the lowest or highest eigenmode of coupled pendulum is excited, and the impurity tends to pin the nonpropagation soliton excitation.

  20. A User Driven Dynamic Circuit Network Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Guok, Chin; Robertson, David; Chaniotakis, Evangelos; Thompson, Mary; Johnston, William; Tierney, Brian

    2008-10-01

    The requirements for network predictability are becoming increasingly critical to the DoE science community where resources are widely distributed and collaborations are world-wide. To accommodate these emerging requirements, the Energy Sciences Network has established a Science Data Network to provide user driven guaranteed bandwidth allocations. In this paper we outline the design, implementation, and secure coordinated use of such a network, as well as some lessons learned.

  1. Data Driven Tuning of Inventory Controllers

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted; Santacoloma, Paloma Andrade; Poulsen, Niels Kjølstad;

    2007-01-01

    A systematic method for criterion based tuning of inventory controllers based on data-driven iterative feedback tuning is presented. This tuning method circumvent problems with modeling bias. The process model used for the design of the inventory control is utilized in the tuning...... as an approximation to reduce time required on experiments. The method is illustrated in an application with a multivariable inventory control implementation on a four tank system....

  2. Database driven scheduling for batch systems

    International Nuclear Information System (INIS)

    Experiments at the Jefferson Laboratory will soon be generating data at the rate of 1 TB/day. In this paper, the authors present a database driven scheme that they are currently implementing in order to ensure the safe archival and subsequent reconstruction of this data. They use a client-server architecture implemented in Java to serve data between the experiments, the mass storage, and the processor farm

  3. Employee-driven Innovation in Welfare Services

    OpenAIRE

    Wihlman, Thomas; Hoppe, Magnus; Wihlman, Ulla; Sandmark, Helene

    2014-01-01

    There is a growing interest in both employee-driven innovation (EDI) and innovation in welfare services, but a lack of empirical studies addressing innovation from the employee perspective. Accordingly, this study was designed to contribute with well-grounded empirical knowledge, aiming to explore the barriers to and opportunities for participation in innovation experienced by employees of the Swedish welfare services. In order to reach the aim, a qualitative thematic analysis of 27 semi-stru...

  4. Ecology-driven stereotypes override race stereotypes

    OpenAIRE

    Williams, Keelah E. G.; Sng, Oliver; Neuberg, Steven L.

    2015-01-01

    Ecological features shape people’s goals, strategies, and behaviors. Our research suggests that social perceivers possess a lay understanding of ecology’s influence on behavior, resulting in ecology-driven stereotypes. Moreover, because race is confounded with ecology in the United States, Americans’ stereotypes about racial groups may actually reflect their stereotypes about these groups’ presumed home ecologies. In a series of studies, we demonstrate that (i) individuals possess ecology-dri...

  5. Directly driven generators for wind power applications

    Energy Technology Data Exchange (ETDEWEB)

    Lampola, P. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Electromechanics

    1995-12-31

    The article deals with an analysis of directly driven, low-speed wind generators. The generators studied were a permanent-magnet synchronous machine and an asynchronous machine. The machines were compared with a typical generator of a wind power plant. The electromagnetic optimization of the machines was done by the finite element method. The rated power of the generators was 500 kW and the rotational speed was 40 rpm. (author)

  6. An Assembler Driven Verification Methodology (ADVM)

    CERN Document Server

    Macbeth, John S; Gray, Ken

    2011-01-01

    This paper presents an overview of an assembler driven verification methodology (ADVM) that was created and implemented for a chip card project at Infineon Technologies AG. The primary advantage of this methodology is that it enables rapid porting of directed tests to new targets and derivatives, with only a minimum amount of code refactoring. As a consequence, considerable verification development time and effort was saved.

  7. Impulsive nature in collisional driven reconnection

    International Nuclear Information System (INIS)

    Compressible magnetohydrodynamic simulation is carried out in order to investigate energy relaxation process of the driven magnetic reconnection in an open finite system through a long time calculation. It is found that a very impulsive energy release occurs in an intermittent fashion through magnetic reconnection for a continuous magnetic flux injection on the boundary. In the impulsive phase, the reconnection rate is remarkably enhanced up to more than ten times of the driving rate on the boundary. (author)

  8. Propeller-driven Outflows and Disk Oscillations

    OpenAIRE

    Romanova, M. M.; Ustyugova, G. V.; Koldoba, A. V.; Lovelace, R. V. E.

    2005-01-01

    We report the discovery of propeller-driven outflows in axisymmetric magnetohydrodynamic simulations of disk accretion to rapidly rotating magnetized stars. Matter outflows in a wide cone and is centrifugally ejected from the inner regions of the disk. Closer to the axis there is a strong, collimated, magnetically dominated outflow of energy and angular momentum carried by the open magnetic field lines from the star. The ``efficiency'' of the propeller may be very high in the respect that mos...

  9. Electrically Driven Technologies for Radioactive Aerosol Abatement

    Energy Technology Data Exchange (ETDEWEB)

    David W. DePaoli; Ofodike A. Ezekoye; Costas Tsouris; Valmor F. de Almeida

    2003-01-28

    The purpose of this research project was to develop an improved understanding of how electriexecy driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume.

  10. Two phase picture in driven polymer translocation

    OpenAIRE

    Saito, Takuya; Sakaue, Takahiro

    2012-01-01

    Two phase picture is a simple and effective methodology to capture the nonequilibrium dynamics of polymer associated with tension propagation. When applying it to the driven translocation process, there is a point to be noted, as briefly discussed in our recent article [Phys. Rev. E 85, 061803 (2012)]. In this article, we address this issue in detail and modify our previous prediction [Euro. Phys. J. E 34, 135 (2011)] by adopting an alternative steady-state ansatz. The modified scaling predic...

  11. Ontology Based Feature Driven Development Life Cycle

    Directory of Open Access Journals (Sweden)

    Farheen Siddiqui

    2012-01-01

    Full Text Available The upcoming technology support for semantic web promises fresh directions for Software Engineering community. Also semantic web has its roots in knowledge engineering that provoke software engineers to look for application of ontology applications throughout the Software Engineering lifecycle. The internal components of a semantic web are "light weight", and may be of less quality standards than the externally visible modules. In fact the internal components are generated from external (ontological component. That's the reason agile development approaches such as feature driven development are suitable for applications internal component development. As yet there is no particular procedure that describes the role of ontology in FDD processes. Therefore we propose an ontology based feature driven development for semantic web application that can be used form application model development to feature design and implementation. Features are precisely defined in the OWL-based domain model. Transition from OWL based domain model to feature list is directly defined in transformation rules. On the other hand the ontology based overall model can be easily validated through automated tools. Advantages of ontology-based feature Driven development are also discussed.

  12. A gasdynamic gun driven by gaseous detonation.

    Science.gov (United States)

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels. PMID:26827358

  13. A gasdynamic gun driven by gaseous detonation

    Science.gov (United States)

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels.

  14. What we learn from surveillance testing of standby turbine driven and motor driven pumps

    Energy Technology Data Exchange (ETDEWEB)

    Christie, B.

    1996-12-01

    This paper describes a comparison of the performance information collected by the author and the respective system engineers from five standby turbine driven pumps at four commercial nuclear electric generating units in the United States and from two standby motor driven pumps at two of these generating units. Information was collected from surveillance testing and from Non-Test actuations. Most of the performance information (97%) came from surveillance testing. {open_quotes}Conditional Probabilities{close_quotes} of the pumps ability to respond to a random demand were calculated for each of the seven standby pumps and compared to the historical record of the Non-Test actuations. It appears that the Conditional Probabilities are comparable to the rate of success for Non-Test actuations. The Conditional Probabilities of the standby motor driven pumps (approximately 99%) are better than the Conditional Probabilities of the standby turbine driven pumps (82%-96% range). Recommendations were made to improve the Conditional Probabilities of the standby turbine driven pumps.

  15. The influence of data-driven versus conceptually-driven processing on the development of PTSD-like symptoms

    NARCIS (Netherlands)

    M. Kindt; M. van den Hout; A. Arntz; J. Drost

    2008-01-01

    Ehlers and Clark [(2000). A cognitive model of posttraumatic stress disorder. Behaviour Research and Therapy, 38, 319-345] propose that a predominance of data-driven processing during the trauma predicts subsequent PTSD. We wondered whether, apart from data-driven encoding, sustained data-driven pro

  16. Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC

    Energy Technology Data Exchange (ETDEWEB)

    Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

    2000-06-01

    We present 2-D particle-in-cell simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approximately} 10{sup 16} W/cm{sup 2}) and high ({approximately} 10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling electron-neutral collisions in a particle-in-cell code.

  17. Isotropically Driven versus Outflow Driven Turbulence: Observational Consequences for Molecular Clouds

    CERN Document Server

    Carroll, Jonathan J; Blackman, Eric G

    2010-01-01

    Feedback from protostellar outflows can influence the nature of turbulence in star forming regions even if they are not the primary source of velocity dispersion for all scales of molecular clouds. For the rate and power expected in star forming regions, we previously (Carroll et al. 2009) demonstrated that outflows could drive supersonic turbulence at levels consistent with the scaling relations from Matzner 2007 although with a steeper velocity power spectrum than expected for an isotropically driven supersonic turbulent cascade. Here we perform higher resolution simulations and combine simulations of outflow driven turbulence with those of isotropically forced turbulence. We find that the presence of outflows within an ambient isotropically driven turbulent environment produces a knee in the velocity power spectrum at the outflow scale and a steeper slope at sub-outflow scales than for a purely isotropically forced case. We also find that the presence of outflows flattens the density spectrum at large scal...

  18. Hysteresis in pressure-driven DNA denaturation.

    Directory of Open Access Journals (Sweden)

    Enrique Hernández-Lemus

    Full Text Available In the past, a great deal of attention has been drawn to thermal driven denaturation processes. In recent years, however, the discovery of stress-induced denaturation, observed at the one-molecule level, has revealed new insights into the complex phenomena involved in the thermo-mechanics of DNA function. Understanding the effect of local pressure variations in DNA stability is thus an appealing topic. Such processes as cellular stress, dehydration, and changes in the ionic strength of the medium could explain local pressure changes that will affect the molecular mechanics of DNA and hence its stability. In this work, a theory that accounts for hysteresis in pressure-driven DNA denaturation is proposed. We here combine an irreversible thermodynamic approach with an equation of state based on the Poisson-Boltzmann cell model. The latter one provides a good description of the osmotic pressure over a wide range of DNA concentrations. The resulting theoretical framework predicts, in general, the process of denaturation and, in particular, hysteresis curves for a DNA sequence in terms of system parameters such as salt concentration, density of DNA molecules and temperature in addition to structural and configurational states of DNA. Furthermore, this formalism can be naturally extended to more complex situations, for example, in cases where the host medium is made up of asymmetric salts or in the description of the (helical-like charge distribution along the DNA molecule. Moreover, since this study incorporates the effect of pressure through a thermodynamic analysis, much of what is known from temperature-driven experiments will shed light on the pressure-induced melting issue.

  19. Combustion-Driven Oscillation in Process Heaters

    Energy Technology Data Exchange (ETDEWEB)

    Seebold, J.G. [Chevron Corporation (Retired), 198 James Avenue, Atherton, CA 94027 (United States)

    2005-10-15

    At this moment in thousands of process heaters all over the world there are, to borrow a phrase from the late Carl Sagan, 'billions and billions' of Btu/hr beneficially being released entirely free of pulsation. On those few occasions, perhaps a dozen and a half in my career, when I would get the inevitable 'Why me?' call, I have generally responsed with something like, 'Consider yourself lucky, you have a rare scientific curiosity on your hands'. Reflecting on the solutions ultimately found, I'm reminded that many years ago my friend Abbott Putnam shared with me an early AGA (American Gas Association) field-service bulletin that included a prescription for eliminating combustion-driven oscillations in home heating units; viz., 'Drill a hole; if that doesn't work, drill another hole' or words to that effect. Many times have I wished that I still had a copy of that bulletin and in this paper we will have occasion, once again, to reflect upon the value of that advice. In this paper we will discuss an instance that arose in a pioneering installation of a breakthrough development of 'extremely', to distinguish it from 'ultra', low-NOx lean premix burner technology. We will illustrate how, when and under what circumstances combustion-driven oscillation can arise; we will touch on the many alternatives for its elimination that were considered and investigated; and we will discuss three practical alternatives for eliminating combustion-driven oscillations.

  20. Neutrino oscillations in magnetically driven supernova explosions

    Energy Technology Data Exchange (ETDEWEB)

    Kawagoe, Shio; Kotake, Kei [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Takiwaki, Tomoya, E-mail: shio.k@nao.ac.jp, E-mail: takiwaki.tomoya@nao.ac.jp, E-mail: kkotake@th.nao.ac.jp [Center for Computational Astrophysics, National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2009-09-01

    We investigate neutrino oscillations from core-collapse supernovae that produce magnetohydrodynamic (MHD) explosions. By calculating numerically the flavor conversion of neutrinos in the highly non-spherical envelope, we study how the explosion anisotropy has impacts on the emergent neutrino spectra through the Mikheyev-Smirnov-Wolfenstein effect. In the case of the inverted mass hierarchy with a relatively large θ{sub 13} (sin{sup 2} 2θ{sub 13} ∼> 10{sup −3}), we show that survival probabilities of ν-bar {sub e} and ν{sub e} seen from the rotational axis of the MHD supernovae (i.e., polar direction), can be significantly different from those along the equatorial direction. The event numbers of ν-bar {sub e} observed from the polar direction are predicted to show steepest decrease, reflecting the passage of the magneto-driven shock to the so-called high-resonance regions. Furthermore we point out that such a shock effect, depending on the original neutrino spectra, appears also for the low-resonance regions, which could lead to a noticeable decrease in the ν{sub e} signals. This reflects a unique nature of the magnetic explosion featuring a very early shock-arrival to the resonance regions, which is in sharp contrast to the neutrino-driven delayed supernova models. Our results suggest that the two features in the ν-bar {sub e} and ν{sub e} signals, if visible to the Super-Kamiokande for a Galactic supernova, could mark an observational signature of the magnetically driven explosions, presumably linked to the formation of magnetars and/or long-duration gamma-ray bursts.

  1. Optical bistability in electrically driven polariton condensates

    OpenAIRE

    Amthor, M.; Liew, T. C. H.; Metzger, C; Brodbeck, S.; Worschech, L.; Kamp, M; Shelykh, I.A.; Kavokin, A. V.; Schneider, C; Höfling, S.

    2015-01-01

    The authors would like to thank the State of Bavaria for financial support. I.A.S. acknowledges the support of FP7 IRSES project POLAPHEN. S.H. gratefully acknowledges support by the Royal Society and the Wolfson Foundation. A.V.K. acknowledges financial support from the Ministry of Education and Science of the Russian Federation (Contract No. 11.G34.31.0067 with SPbSU), and EU projects POLAPHEN, SPANGL4Q, and LIMACONA. We observe a bistability in an electrically driven polariton condensat...

  2. Model-driven software migration a methodology

    CERN Document Server

    Wagner, Christian

    2014-01-01

    Today, reliable software systems are the basis of any business or company. The continuous further development of those systems is the central component in software evolution. It requires a huge amount of time- man power- as well as financial resources. The challenges are size, seniority and heterogeneity of those software systems. Christian Wagner addresses software evolution: the inherent problems and uncertainties in the process. He presents a model-driven method which leads to a synchronization between source code and design. As a result the model layer will be the central part in further e

  3. Plasma-driven ultrashort bunch diagnostics

    Science.gov (United States)

    Dornmair, I.; Schroeder, C. B.; Floettmann, K.; Marchetti, B.; Maier, A. R.

    2016-06-01

    Ultrashort electron bunches are crucial for an increasing number of applications, however, diagnosing their longitudinal phase space remains a challenge. We propose a new method that harnesses the strong electric fields present in a laser driven plasma wakefield. By transversely displacing driver laser and witness bunch, a streaking field is applied to the bunch. This field maps the time information to a transverse momentum change and, consequently, to a change of transverse position. We illustrate our method with simulations where we achieve a time resolution in the attosecond range.

  4. Soil stress field around driven piles

    OpenAIRE

    Allard, Marie-Agnes

    1989-01-01

    The description, equipment, and results of a series of pile-driving experiments conducted in a centrifuge using a model pile driven in dry sand are presented. The work was conceived on the basis of the modelling of a soil-structure system under an artificially generated gravitational field, and motivated by the need for experimental data for a better understanding of the complex phenomena involved in the pile-soil interaction during driving. The behavior of the pile itself has been the fo...

  5. Surface Tension Driven Convection Experiment Completed

    Science.gov (United States)

    Jacobson, Thomas P.; Sedlak, Deborah A.

    1997-01-01

    The Surface Tension Driven Convection Experiment (STDCE) was designed to study basic fluid mechanics and heat transfer on thermocapillary flows generated by temperature variations along the free surfaces of liquids in microgravity. STDCE first flew on the USML-1 mission in July 1992 and was rebuilt for the USML-2 mission that was launched in October 1995. This was a collaborative project with principal investigators from Case Western Reserve University (CWRU), Professors Simon Ostrach and Yasuhiro Kamotani, along with a team from the NASA Lewis Research Center composed of civil servants and contractors from Aerospace Design & Fabrication, Inc. (ADF), Analex, and NYMA, Inc.

  6. Radiation Driven Implosion and Triggered Star Formation

    CERN Document Server

    Bisbas, T G; Wünsch, R; Hubber, D A; Walch, S

    2010-01-01

    We present simulations of initially stable isothermal clouds exposed to ionizing radiation from a discrete external source, and identify the conditions that lead to radiatively driven implosion and star formation. We use the Smoothed Particle Hydrodynamics code SEREN (Hubber et al. 2010) and the HEALPix-based photoionization algorithm described in Bisbas et al. (2009). We find that the incident ionizing flux is the critical parameter determining the evolution: high fluxes simply disperse the cloud, whereas low fluxes trigger star formation. We find a clear connection between the intensity of the incident flux and the parameters of star formation.

  7. Current-driven phenomena in nanoelectronics

    CERN Document Server

    Seideman, Tamar

    2010-01-01

    Consisting of ten chapters written by some of the world's leaders in the field, this book combines experimental, theoretical and numerical studies of current-driven phenomena in the nanoscale. The topics covered range from single-molecule, site-specific nanochemistry induced by a scanning tunneling microscope, through inelastic tunneling spectroscopy and current-induced heating, to current-triggered molecular machines. The various chapters focus on experimental and numerical method development, the description of specific systems, and new ideas and novel phenomena.

  8. Mobile dashboard for event driven architectures

    OpenAIRE

    Janković, Marko

    2012-01-01

    The use of EDA is nowadays present in various fields like smart houses and cities, health care, traffic control, Internet of things etc. The main objective is to enable the monitoring of system activity in real time, which enables faster and more efficient decision-making and helps taking appropriate measures. The latter was also the main motivation and reason for the development of the mobile control panel for the event-driven Occapi platform, the purpose of which is to enable users to mo...

  9. Research on Virtual Vehicle Driven with Vision

    Directory of Open Access Journals (Sweden)

    Youquan Liu

    2011-08-01

    Full Text Available This paper presents a traffic-oriented modeling and simulation framework. With this tool, users can create a traffic scene quickly and easily, and then drive the vehicle in the created scene with physics simulated. Especially, the vehicle could be driven with vision technology, which is equipped with a webcam and a paper printed with controlling markers. And the paper is used as the virtual wheel to control the motion of the vehicle. At such low cost, many people can enjoy the driving fun; it also provides an easy and interesting way for driving video games with promising business values.

  10. Laser driven proton acceleration and beam shaping

    OpenAIRE

    Sinigardi, Stefano

    2014-01-01

    In the race to obtain protons with higher energies, using more compact systems at the same time, laser-driven plasma accelerators are becoming an interesting possibility. But for now, only beams with extremely broad energy spectra and high divergence have been produced. The driving line of this PhD thesis was the study and design of a compact system to extract a high quality beam out of the initial bunch of protons produced by the interaction of a laser pulse with a thin solid target, usi...

  11. Novelty-driven Particle Swarm Optimization

    DEFF Research Database (Denmark)

    Galvao, Diana; Lehman, Joel Anthony; Urbano, Paulo

    2015-01-01

    Particle Swarm Optimization (PSO) is a well-known population-based optimization algorithm. Most often it is applied to optimize objective-based fitness functions that reward progress towards a desired objective or behavior. As a result, search increasingly focuses on higher-fitness areas. However......, in problems with many local optima, such focus often leads to premature convergence that precludes reaching the intended objective. To remedy this problem in certain types of domains, this paper introduces Novelty-driven Particle Swarm Optimization (NdPSO), which is motivated by the novelty search algorithm...

  12. Plasma-driven ultrashort bunch diagnostic

    CERN Document Server

    Dornmair, I; Floettmann, K; Marchetti, B; Maier, A R

    2016-01-01

    Ultrashort electron bunches are crucial for an increasing number of applications, however, diagnosing their longitudinal phase space remains a challenge. We propose a new method that harnesses the strong electric fields present in a laser driven plasma wakefield. By transversely displacing driver laser and witness bunch, a streaking field is applied to the bunch. This field maps the time information to a transverse momentum change and, consequently, to a change of transverse position. We illustrate our method with simulations where we achieve a time resolution in the attosecond range.

  13. Neutrino Physics with Accelerator Driven Subcritical Reactors

    CERN Document Server

    Ciuffoli, Emilio; Zhao, Fengyi

    2015-01-01

    Accelerator driven system (ADS) subcritical nuclear reactors are under development around the world. They will be intense sources of free, 30-50 MeV antimuon decay at rest antimuon neutrinos. These ADS reactor neutrinos can provide a robust test of the LSND anomaly and a precise measurement of the leptonic CP-violating phase delta, including sign(cos(delta)). The first phase of many ADS programs includes the construction of a low energy, high intensity proton or deuteron accelerator, which can yield competitive bounds on sterile neutrinos.

  14. Towards Player-Driven Procedural Content Generation

    DEFF Research Database (Denmark)

    Shaker, Noor; Yannakakis, Georgios N.; Togelius, Julian

    2012-01-01

    Generating immersive game content is one of the ultimate goals for a game designer. This goal can be achieved by realizing the fact that players’ perception of the same game differ according to a number of factors including: players’ personality, playing styles, expertise and culture background....... While one player might find the game immersive, others may quit playing as a result of encountering a seemingly insoluble problem. One promising avenue towards optimizing the gameplay experience for individual game players is to tailor player experience in real-time via automatic game content generation......-driven content generation....

  15. Heat pumping with optically driven excitons

    CERN Document Server

    Gauger, Erik M

    2010-01-01

    We present a theoretical study showing that an optically driven excitonic two-level system in a solid state environment acts as a heat pump by means of repeated phonon emission or absorption events. We derive a master equation for the combined phonon bath and two-level system dynamics and analyze the direction and rate of energy transfer as a function of the externally accessible driving parameters. We discover that if the driving laser is detuned from the exciton transition, cooling the phonon environment becomes possible.

  16. Current-driven electron drift solitons

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Ali, E-mail: aliahmad79@hotmail.com [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT) Islamabad (Pakistan); Saleem, H. [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT) Islamabad (Pakistan)

    2013-12-09

    The soliton formation by the current-driven drift-like wave is investigated for heavier ion (such as barium) plasma experiments planned to be performed in future. It is pointed out that the sheared flow of electrons can give rise to short scale solitary structures in the presence of stationary heavier ions. The nonlinearity appears due to convective term in the parallel equation of motion and not because of temperature gradient unlike the case of low frequency usual drift wave soliton. This higher frequency drift-like wave requires sheared flow of electrons and not the density gradient to exist.

  17. Optimality of contraction-driven crawling

    CERN Document Server

    Recho, P; Truskinovsky, L

    2014-01-01

    We study a model of cell motility where the condition of optimal trade-off between performance and metabolic cost can be made precise. In this model a steadily crawling fragment is represented by a layer of active gel placed on a frictional surface and driven by contraction only. We find analytically the distribution of contractile elements (pullers) ensuring that the efficiency of self-propulsion is maximal. We then show that natural assumptions about advection and diffusion of pullers produce a distribution that is remarkably close to the optimal one and is qualitatively similar to the one observed in experiments on fish keratocytes.

  18. Meshless simulation for skeleton driven elastic deformation

    Institute of Scientific and Technical Information of China (English)

    SONG Chao; ZHANG Hong-xin; HUANG Jin; BAO Hu-jun

    2006-01-01

    A meshless simulation system is presented for elastic deformation driven by skeleton in this paper. In this system, we propose a new method for calculating node rotation while applying a similar technique with stiffness warping to tackle the nonlinear large deformation. In our method, all node rotations are evaluated from sampling points in attached skeleton by constructing and solving the diffusion partial differential equation. The experiments indicated that the method can enhance the stability of the dynamics and avoid fussy sub-step calculation in static deformation edition. Moreover, rational deformation results for the area around the skeleton joints can be simulated without user interaction by adopting the simplified technique.

  19. Is Earthquake Triggering Driven by Small Earthquakes?

    CERN Document Server

    Helmstetter, A

    2002-01-01

    Using a catalog of seismicity for Southern California, we measure how the number of triggered earthquakes increases with the earthquake magnitude. The trade-off between this scaling and the distribution of earthquake magnitudes controls the relative role of small compared to large earthquakes. We show that seismicity triggering is driven by the smallest earthquakes, which trigger fewer aftershocks than larger earthquakes, but which are much more numerous. We propose that the non-trivial scaling of the number of aftershocks emerges from the fractal spatial distribution of aftershocks.

  20. Functionality-driven fractionation of lupin seeds

    OpenAIRE

    Berghout, J.A.M.

    2015-01-01

    Functionality-driven fractionation of lupin seeds The growth in the world population requires an increase in the production of protein-rich foods from plant-based materials. Lupin seeds have potential to become a novel plant protein source for food products because they are rich in protein (about 37 wt%) and they can be grown in moderate temperature climates as in north-western Europe. Besides a high protein content, lupin seeds are rich in dietary fibres (soluble and insoluble), contain abou...

  1. Current and noise in driven heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Franz

    2009-02-18

    In this thesis we consider the electron transport in nanoscale systems driven by an external energy source. We introduce a tight-binding Hamiltonian containing an interaction term that describes a very strong Coulomb repulsion between electrons in the system. Since we deal with time-dependent situations, we employ a Floquet theory to take into account the time periodicity induced by different external oscillating fields. For the two-level system, we even provide an analytical solution for the eigenenergies with arbitrary phase shift between the levels for a cosine-shaped driving. To describe time-dependent driven transport, we derive a master equation by tracing out the influence of the surrounding leads in order to obtain the reduced density operator of the system. We generalise the common master equation for the reduced density operator to perform an analysis of the noise characteristics. The concept of Full Counting Statistics in electron transport gained much attention in recent years proven its value as a powerful theoretical technique. Combining its advantages with the master equation approach, we find a hierarchy in the moments of the electron number in one lead that allows us to calculate the first two cumulants. The first cumulant can be identified as the current passing through the system, while the noise of this transmission process is reflected by the second cumulant. Moreover, in combination with our Floquet approach, the formalism is not limited to static situations, which we prove by calculating the current and noise characteristics for the non-adiabatic electron pump. We study the influence of a static energy disorder on the maximal possible current for different realisations. Further, we explore the possibility of non-adiabatically pumping electrons in an initially symmetric system if random fluctuations break this symmetry. Motivated by recent and upcoming experiments, we use our extended Floquet model to properly describe systems driven by

  2. Towards a precession driven dynamo experiment

    CERN Document Server

    Stefani, F; Gerbeth, G; Giesecke, A; Gundrum, T; Herault, J; Nore, C; Steglich, C

    2014-01-01

    The most ambitious project within the DREsden Sodium facility for DYNamo and thermohydraulic studies (DRESDYN) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is the set-up of a precession-driven dynamo experiment. After discussing the scientific background and some results of water pre-experiments and numerical predictions, we focus on the numerous structural and design problems of the machine. We also outline the progress of the building's construction, and the status of some other experiments that are planned in the framework of DRESDYN.

  3. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  4. Power spectra of outflow-driven turbulence

    CERN Document Server

    Moraghan, Anthony; Yoon, Suk-Jin

    2015-01-01

    We investigate the power spectra of outflow-driven turbulence through high-resolution three-dimensional isothermal numerical simulations where the turbulence is driven locally in real-space by a simple spherical outflow model. The resulting turbulent flow saturates at an average Mach number of ~2.5 and is analysed through density and velocity power spectra, including an investigation of the evolution of the solenoidal and compressional components. We obtain a shallow density power spectrum with a slope of ~-1.2 attributed to the presence of a network of localised dense filamentary structures formed by strong shock interactions. The total velocity power spectrum slope is found to be ~-2.0, representative of Burgers shock dominated turbulence model. The density weighted velocity power spectrum slope is measured as ~-1.6, slightly less than the expected Kolmogorov scaling value (slope of -5/3) found in previous works. The discrepancy may be caused by the nature of our real space driving model and we suggest ther...

  5. Accelerating Science Driven System Design With RAMP

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynek, John [Univ. of California, Berkeley, CA (United States)

    2015-05-01

    Researchers from UC Berkeley, in collaboration with the Lawrence Berkeley National Lab, are engaged in developing an Infrastructure for Synthesis with Integrated Simulation (ISIS). The ISIS Project was a cooperative effort for “application-driven hardware design” that engages application scientists in the early parts of the hardware design process for future generation supercomputing systems. This project served to foster development of computing systems that are better tuned to the application requirements of demanding scientific applications and result in more cost-effective and efficient HPC system designs. In order to overcome long conventional design-cycle times, we leveraged reconfigurable devices to aid in the design of high-efficiency systems, including conventional multi- and many-core systems. The resulting system emulation/prototyping environment, in conjunction with the appropriate intermediate abstractions, provided both a convenient user programming experience and retained flexibility, and thus efficiency, of a reconfigurable platform. We initially targeted the Berkeley RAMP system (Research Accelerator for Multiple Processors) as that hardware emulation environment to facilitate and ultimately accelerate the iterative process of science-driven system design. Our goal was to develop and demonstrate a design methodology for domain-optimized computer system architectures. The tangible outcome is a methodology and tools for rapid prototyping and design-space exploration, leading to highly optimized and efficient HPC systems.

  6. User Driven Innovation in the Building Process

    Institute of Scientific and Technical Information of China (English)

    Per Christiansson; Kistian Birch Sorensen; Mette Rodtness; Mette Abrahamsen; Lars Ostenfeld Riemnann; Morten Alsdorf

    2008-01-01

    During the late years there has been an ever-increasing focus on the possibilities to change the building process to raise quality on the final building products as well as the activities of actors involved in the building process. One reason for this interest is the new opportunities evolving due to introduction of ad-vanced information and communication technology (ICT). The paper focuses on creative changes of the building process powered by user driven innovation activities. An overview of existing user driven innovation methodologies is given as well experiences from the ongoing Virtual Innovation in Construction (VIC) project.One important driving force for change is the opportunity for users to develop and articulate real needs con-cerning for example different functionalities of a building and its parts, but also on artifacts supporting the ac-tual needs capture and requirements formulation during building design. A general methodological frame-work and meta ontology for Virtual Innovation in Construction is presented as well as findings from imple-mentation of the method.

  7. Piezoelectric driven thermo-acoustic refrigerator

    Science.gov (United States)

    Chinn, D. G.; Nouh, M.; Aldraihem, O.; Baz, A.

    2011-03-01

    Thermoacoustic refrigeration is an emerging refrigeration technology which does not rely for in its operation on the use of any moving parts or harmful refrigerants. This technology uses acoustic waves to pump heat across a temperature gradient. The vast majority of thermoacoustic refrigerators to date have used electromagnetic loudspeakers to generate the acoustic input. In this paper, the design, construction, operation, and modeling of a piezoelectric-driven thermoacoustic refrigerator are detailed. This refrigerator demonstrates the effectiveness of piezoelectric actuation in moving 0.3 W of heat across an 18 degree C temperature difference with an input power of 7.6 W. The performance characteristics of this class of thermoacoustic-piezoelectric refrigerator are modeled using DeltaEC software and the predictions are validated experimentally. The obtained results confirm the validity of the developed model. Furthermore, the potential of piezoelectric actuation as effective means for driving thermoacoustic refrigerators is demonstrated as compared to the conventional electromagnetic loudspeakers which are heavy and require high actuation energy. The developed theoretical and experimental tools can serve as invaluable means for the design and testing of other piezoelectric driven thermoacoustic refrigerator configurations.

  8. Periodically driven three-level systems

    Science.gov (United States)

    Kenmoe, M. B.; Fai, L. C.

    2016-09-01

    We study the dynamics of a three-level system (ThLS) sinusoidally driven in both longitudinal and transverse directions and in the presence of a uniaxial anisotropy D entering the generic Hamiltonian through the zero-energy splitting term D (Sz)2 where Sz is the projection of the spin vector along the quantization direction. As a consequence of the addition of this term, the order of the symmetry group of the Hamiltonian is increased by a unit and we observe a sequence of cascaded SU(3) Landau-Zener-Stückelberg-Majorana (LZSM) interferometers. The study is carried out by analytically and numerically calculating the probabilities of nonadiabatic and adiabatic evolutions. For nonadiabatic evolutions, two main approximations based on the weak and strong driving limits are discussed by comparing the characteristic frequency of the longitudinal drive with the amplitudes of driven fields. For each of the cases discussed, our analytical results quite well reproduce the gross temporal profile of the exact numerical probabilities. This allows us to check the range of validity of analytical results and confirm our assumptions. For adiabatic evolutions, a general theory is constructed allowing for the description of adiabatic passages in arbitrary ThLSs in which direct transitions between states with extremal spin projections are forbidden. A compact formula for adiabatic evolutions is derived and numerically tested for some illustrative cases. Interference patterns demonstrating multiple LZSM transitions are reported. Applications of our results to the nitrogen vacancy center in diamond are discussed.

  9. Heat driven refrigeration cycle at low temperatures

    Institute of Scientific and Technical Information of China (English)

    HE Yijian; HONG Ronghua; CHEN Guangming

    2005-01-01

    Absorption refrigeration cycle can be driven by low-grade thermal energy, such as solar energy, geothermal energy and waste heat. It is beneficial to save energy and protect environment. However, the applications of traditional absorption refrigeration cycle are greatly restricted because they cannot achieve low refrigeration temperature. A new absorption refrigeration cycle is investigated in this paper, which is driven by low-grade energy and can get deep low refrigeration temperature. The mixture refrigerant R23+R134a and an absorbent DMF are used as its working fluid. The theoretical results indicate that the new cycle can achieve -62℃ refrigeration temperature when the generation temperature is only 160℃. This refrigeration temperature is much lower than that obtained by traditional absorption refrigeration cycle. Refrigeration temperature of -47.3℃ has been successfully achieved by experiment for this new cycle at the generation temperature of 157℃, which is the lowest temperature obtained by absorption refrigeration system reported in the literature up to now. The theoretical and experimental results prove that new cycle can achieve rather low refrigeration temperature.

  10. Isotropically Driven Versus Outflow Driven Turbulence: Observational Consequences for Molecular Clouds

    Science.gov (United States)

    Carroll, Jonathan J.; Frank, Adam; Blackman, Eric G.

    2010-10-01

    Feedback from protostellar outflows can influence the nature of turbulence in star-forming regions even if they are not the primary source of velocity dispersion for all scales of molecular clouds. For the rate and power expected in star-forming regions, we previously (Carroll et al.) demonstrated that outflows could drive supersonic turbulence at levels consistent with the scaling relations from Matzner although with a steeper velocity power spectrum than expected for an isotropically driven supersonic turbulent cascade. Here, we perform higher resolution simulations and combine simulations of outflow driven turbulence with those of isotropically forced turbulence. We find that the presence of outflows within an ambient isotropically driven turbulent environment produces a knee in the velocity power spectrum at the outflow scale and a steeper slope at sub-outflow scales than for a purely isotropically forced case. We also find that the presence of outflows flattens the density spectrum at large scales effectively reducing the formation of large-scale turbulent density structures. These effects are qualitatively independent of resolution. We have also carried out Principal Component Analysis (PCA) for synthetic data from our simulations. We find that PCA as a tool for identifying the driving scale of turbulence has a misleading bias toward low amplitude large-scale velocity structures even when they are not necessarily the dominant energy containing scales. This bias is absent for isotropically forced turbulence but manifests strongly for collimated outflow driven turbulence.

  11. The mechanics of gravity-driven faulting

    Directory of Open Access Journals (Sweden)

    L. Barrows

    2010-04-01

    Full Text Available Faulting can result from either of two different mechanisms. These involve fundamentally different energetics. In elastic rebound, locked-in elastic strain energy is transformed into the earthquake (seismic waves plus work done in the fault zone. In force-driven faulting, the forces that create the stress on the fault supply work or energy to the faulting process. Half of this energy is transformed into the earthquake and half goes into an increase in locked-in elastic strain. In elastic rebound the locked-in elastic strain drives slip on the fault. In force-driven faulting it stops slip on the fault.

    Tectonic stress is reasonably attributed to gravity acting on topography and the Earth's lateral density variations. This includes the thermal convection that ultimately drives plate tectonics. Mechanical analysis has shown the intensity of the gravitational tectonic stress that is associated with the regional topography and lateral density variations that actually exist is comparable with the stress drops that are commonly associated with tectonic earthquakes; both are in the range of tens of bar to several hundred bar.

    The gravity collapse seismic mechanism assumes the fault fails and slips in direct response to the gravitational tectonic stress. Gravity collapse is an example of force-driven faulting. In the simplest case, energy that is released from the gravitational potential of the stress-causing topography and lateral density variations is equally split between the earthquake and the increase in locked-in elastic strain.

    The release of gravitational potential energy requires a change in the Earth's density distribution. Gravitational body forces are solely dependent on density so a change in the density distribution requires a change in the body forces. This implies the existence of volumetric body-force displacements. The volumetric body-force displacements are in addition to displacements generated by slip on

  12. Just-in-time Database-Driven Web Applications

    OpenAIRE

    Ong, Kenneth R

    2003-01-01

    "Just-in-time" database-driven Web applications are inexpensive, quickly-developed software that can be put to many uses within a health care organization. Database-driven Web applications garnered 73873 hits on our system-wide intranet in 2002. They enabled collaboration and communication via user-friendly Web browser-based interfaces for both mission-critical and patient-care-critical functions. Nineteen database-driven Web applications were developed. The application categories that compri...

  13. Laser Driven Neutron Sources: Characteristics, Applications and Prospects

    OpenAIRE

    Alvarez Ruiz, Jesus; Fernández-Tobias, J.; Mima, K.; Nakai, S; S. Kar; Kato, Y.; Perlado Martin, Jose Manuel

    2012-01-01

    The basics of laser driven neutron sources, properties and possible applications are discussed. We describe the laser driven nuclear processes which trigger neutron generation, namely, nuclear reactions induced by laser driven ion beam (ion n), thermonuclear fusion by implosion and photo-induced nuclear (gamma n) reactions. Based on their main properties, i.e. point source (< 100 μm) and short durations (< ns), different applications are described, such as radiography, time-resolved spe...

  14. Optimization and Performance Analysis of Bulk-Driven Differential Amplifier

    Directory of Open Access Journals (Sweden)

    Antarpreet kaur

    2014-04-01

    Full Text Available In recent years, there has been an increasing demand for high-speed digital circuits at low power consumption. This paper presents a design of input stage of Operational Amplifier i.e cascode differential amplifier using a standard 65nm CMOS Technology.A comparison betweem gate-driven, bulk-driven and cascode bulk driven bulk-driven differential amplifier is described. The Results demonstrate that CMMR is 83.98 dB, 3-dB Bandwidth is 1.04 MHz. The circuit dissipate power of 28uWunder single supply of 1.0V.

  15. OMOGENIA: A Semantically Driven Collaborative Environment

    Science.gov (United States)

    Liapis, Aggelos

    Ontology creation can be thought of as a social procedure. Indeed the concepts involved in general need to be elicited from communities of domain experts and end-users by teams of knowledge engineers. Many problems in ontology creation appear to resemble certain problems in software design, particularly with respect to the setup of collaborative systems. For instance, the resolution of conceptual conflicts between formalized ontologies is a major engineering problem as ontologies move into widespread use on the semantic web. Such conflict resolution often requires human collaboration and cannot be achieved by automated methods with the exception of simple cases. In this chapter we discuss research in the field of computer-supported cooperative work (CSCW) that focuses on classification and which throws light on ontology building. Furthermore, we present a semantically driven collaborative environment called OMOGENIA as a natural way to display and examine the structure of an evolving ontology in a collaborative setting.

  16. Employee Driven Innovation in Team (EDIT)

    DEFF Research Database (Denmark)

    Kristiansen, Marianne; Bloch-Poulsen, Jørgen

    2010-01-01

    innovations co-created across conflicting workplace interests in and between teams. The article argues that it is meaningful to assert that every employee has an innovative potential, no matter of what educational background or sector and that sometimes, this innovative potential might be facilitated through......The article deals with employee driven innovation in regular teams from a critical, pragmatic action research perspective, referring to theories on innovation, dialogue, workplace learning, and organizational communication. It is based on an action research project "Innovation and involvement...... on innovation, workplace learning and action research, and presents EDI as a fairly new field of research. EDI is conceptualized as a participatory endeavour differing from a mainstream understanding of innovation as surplus value for the organization. The article focuses on incremental, organizational process...

  17. RF Electron Gun with Driven Plasma Cathode

    CERN Document Server

    Khodak, Igor

    2005-01-01

    It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

  18. Buoyancy driven turbulence and distributed chaos

    CERN Document Server

    Bershadskii, A

    2016-01-01

    It is shown, using results of recent direct numerical simulations, laboratory experiments and atmospheric measurements, that buoyancy driven turbulence exhibits a broad diversity of the types of distributed chaos with its stretched exponential spectrum $\\exp(-k/k_{\\beta})^{\\beta}$. The distributed chaos with $\\beta = 1/3$ (determined by the helicity correlation integral) is the most common feature of the stably stratified turbulence (due to the strong helical waves presence). These waves mostly dominate spectral properties of the vertical component of velocity field, while the horizontal component is dominated by the diffusive processes both for the weak and strong stable stratification ($\\beta =2/3$). For the last case influence of the low boundary can overcome the wave effects and result in $\\beta =1/2$ for the vertical component of the velocity field (the spontaneous breaking of the space translational symmetry - homogeneity). For the unstably stratified turbulence in the Rayleigh-Taylor mixing zone the di...

  19. Hydrodynamically driven colloidal assembly in dip coating.

    Science.gov (United States)

    Colosqui, Carlos E; Morris, Jeffrey F; Stone, Howard A

    2013-05-01

    We study the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth substrates. Below a critical withdrawal speed where the coating film is thinner than the particle diameter, capillary forces induced by deformation of the free surface prevent the convective transport of single particles through the meniscus beneath the film. Capillary-induced forces are balanced by hydrodynamic drag only after a minimum number of particles assemble within the meniscus. The particle assembly can thus enter the thin film where it moves at nearly the withdrawal speed and rapidly separates from the next assembly. The interplay between hydrodynamic and capillary forces produces periodic and regular structures below a critical ratio Ca(2/3)/sqrt[Bo] particles in suspension. The hydrodynamically driven assembly documented here is consistent with stripe pattern formations observed experimentally in dip coating.

  20. Stochastically driven instability in rotating shear flows

    CERN Document Server

    Mukhopadhyay, Banibrata

    2012-01-01

    Origin of hydrodynamic turbulence in rotating shear flows is investigated. The particular emphasis is the flows whose angular velocity decreases but specific angular momentum increases with increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain observed data. Such a mismatch between the linear theory and observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and then the corresponding turbulence therein is ruled out. The present work explores the effect of stochastic noise on such hydrodynamic flows. We essentially concentrate on a small section of such a flow which is nothing but a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disk. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities, and hence large energy dissipations of perturbation, which presumably generate instability. A ra...

  1. Static Checking of Interrupt-driven Software

    DEFF Research Database (Denmark)

    Brylow, Dennis; Damgaard, Niels; Palsberg, Jens

    2001-01-01

    in a few seconds on a standard PC. Our tool is one of the first to give an efficient and useful static analysis of assembly code. It enables increased confidence in correctness, significantly reduced testing requirements, and support for maintenance throughout the system life-cycle....... require extensive brute-force testing, making development and maintenance costly. This is particularly true for system components that are written in assembly language. Static checking has the potential of alleviating these problems, but until now there has been little tool support for programming...... at the assembly level. In this paper we present the design and implementation of a static checker for interrupt-driven Z86-based software with hard real-time requirements. For six commercial microcontrollers, our checker has produced upper bounds on interrupt latencies and stack sizes, as well as verified...

  2. Target-driven merging of Taxonomies

    CERN Document Server

    Raunich, Salvatore

    2010-01-01

    The proliferation of ontologies and taxonomies in many domains increasingly demands the integration of multiple such ontologies. The goal of ontology integration is to merge two or more given ontologies in order to provide a unified view on the input ontologies while maintaining all information coming from them. We propose a new taxonomy merging algorithm that, given as input two taxonomies and an equivalence matching between them, can generate an integrated taxonomy in a fully automatic manner. The approach is target-driven, i.e. we merge a source taxonomy into the target taxonomy and preserve the structure of the target ontology as much as possible. We also discuss how to extend the merge algorithm providing auxiliary information, like additional relationships between source and target concepts, in order to semantically improve the final result. The algorithm was implemented in a working prototype and evaluated using synthetic and real-world scenarios.

  3. Bug Localization in Test-Driven Development

    Directory of Open Access Journals (Sweden)

    Massimo Ficco

    2011-01-01

    Full Text Available Software development teams that use agile methodologies are increasingly adopting the test-driven development practice (TDD. TDD allows to produce software by iterative and incremental work cycle, and with a strict control over the process, favouring an early detection of bugs. However, when applied to large and complex systems, TDD benefits are not so obvious; manually locating and fixing bugs introduced during the iterative development steps is a nontrivial task. In such systems, the propagation chains following the bugs activation can be unacceptably long and intricate, and the size of the code to be analyzed is often too large. In this paper, a bug localization technique specifically tailored to TDD is presented. The technique is embedded in the TDD cycle, and it aims to improve developers' ability to locate bugs as soon as possible. It is implemented in a tool and experimentally evaluated on newly developed Java programs.

  4. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit...

  5. User-Driven Innovation: An Exploratory Study

    Directory of Open Access Journals (Sweden)

    Blanka Tacer

    2015-03-01

    Full Text Available Despite the relatively robust promotion of user-driven innovation (UDI in practice, research on UDI remains in its early stages. Following a grounded theory analysis approach, this paper makes a contribution by conducting exploratory research of the field. Nine interviews yield an empirical basis for extracting categories connected with existing conceptual issues. The results reveal three key elements of the UDI (user involvement, searching for feedback, and design orientation. The results also indicate the interdisciplinary nature of UDI with branding, design, and company-user interaction as complementary fields in creating user experience. The analysis leads to four theoretical propositions for future studies. The article concludes with limitations and implications for future research.

  6. Wave energy driven resonant sea water pump

    Energy Technology Data Exchange (ETDEWEB)

    Czitrom, S.P.R. [UNAM, Mexico City (Mexico). Inst. de Ciencias del Mar y Limnologia

    1996-12-31

    A wave driven sea-water pump which operates by resonance is described. Oscillations in the resonant and exhaust ducts perform similar to two mass-spring systems coupled by a third spring acting for the compression chamber. Performance of the pump is optimized by means of a variable volume air compression chamber (patents pending) which tunes the system to the incoming wave frequency. Wave tank experiments with an instrumented, 1:20 scale model of the pump are described. Performance was studied under various wave and tuning conditions and compared to a numerical model which was found to describe the system accurately. Successful sea trials at an energetic coastline provide evidence of the system`s viability under demanding conditions.

  7. Turbulence driven particle transport in Texas Helimak

    International Nuclear Information System (INIS)

    We analyze the turbulence driven particle transport in Texas Helimak [K. W. Gentle and H. He, Plasma Sci. Technol. 10, 284 (2008)], a toroidal plasma device with a one-dimensional equilibrium with magnetic curvature and shear. Alterations on the radial electric field, through an external voltage bias, change the spectral plasma characteristics inducing a dominant frequency for negative bias values and a broad band frequency spectrum for positive bias values. When applying a negative bias, the transport is high where the waves propagate with phase velocities near the plasma flow velocity, an indication that the transport is strongly affected by a wave particle resonant interaction. On the other hand, for positive bias values, the plasma has a reversed shear flow, and we observe that the transport is almost zero in the shearless radial region, an evidence of a transport barrier in this region.

  8. Temperature gradient driven lasing and stimulated cooling

    CERN Document Server

    Sandner, K

    2012-01-01

    A laser can be understood as thermodynamic engine converting heat to a coherent single mode field close to Carnot efficiency. From this perspective spectral shaping of the excitation light generates a higher effective temperature on the pump than on the gain transition. Here, using a toy model of a quantum well structure with two suitably designed tunnel-coupled wells kept at different temperature, we study a laser operated on an actual spatial temperature gradient between pump and gain region. We predict gain and narrow band laser emission for a sufficient temperature gradient and resonator quality. Lasing appears concurrent with amplified heat flow and points to a new form of stimulated solid state cooling. Such a mechanism could raise the operating temperature limit of quantum cascade lasers by substituting phonon emission driven injection, which generates intrinsic heat, by an extended model with phonon absorption steps.

  9. Laser-Driven Mini-Thrusters

    International Nuclear Information System (INIS)

    Laser-driven mini-thrusters were studied using Delrin registered and PVC (Delrin registered is a registered trademark of DuPont) as propellants. TEA CO2 laser (λ = 10.6 μm) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse

  10. Cyclic game dynamics driven by iterated reasoning

    CERN Document Server

    Frey, Seth

    2012-01-01

    Recent theories from complexity science argue that complex dynamics are ubiquitous in social and economic systems. These claims emerge from the analysis of individually simple agents whose collective behavior is surprisingly complicated. However, game theorists have argued that iterated reasoning-our ability to think through what you think I think you think-will prevent complex dynamics and facilitate convergence to classic equilibria. We report stable and efficient periodic behavior in human groups playing the Mod Game, a multi-player game similar to Rock-Paper-Scissors. The game rewards subjects for thinking exactly one step ahead of others in their group. Groups that play this game exhibit cycles that are inconsistent with any fixed-point equilibrium concept. These cycles are driven by a "hopping" behavior that can only be explained by iterated reasoning. If iterated reasoning can be complicit in complex dynamics, then game cycles and chaos may realistically be driving fluctuations in real-world social and...

  11. Driven synchronization in random networks of oscillators

    CERN Document Server

    Hindes, Jason

    2015-01-01

    Synchronization is a universal phenomenon found in many non-equilibrium systems. Much recent interest in this area has overlapped with the study of complex networks, where a major focus is determining how a system's connectivity patterns affect the types of behavior that it can produce. Thus far, modeling efforts have focused on the tendency of networks of oscillators to mutually synchronize themselves, with less emphasis on the effects of external driving. In this work we discuss the interplay between mutual and driven synchronization in networks of phase oscillators of the Kuramoto type, and resolve how the structure and emergence of such states depends on the underlying network topology for simple random networks with a given degree distribution. We provide a partial bifurcation analysis, centering on the appearance of a Takens-Bogdanov-Cusp singularity, which broadly separates homogeneous and heterogeneous network behavior in a weak coupling limit, and from which the number, stability and appearance of dr...

  12. Bistability in a Driven-Dissipative Superfluid

    Science.gov (United States)

    Labouvie, Ralf; Santra, Bodhaditya; Heun, Simon; Ott, Herwig

    2016-06-01

    We experimentally study a driven-dissipative Josephson junction array, realized with a weakly interacting Bose-Einstein condensate residing in a one-dimensional optical lattice. Engineered losses on one site act as a local dissipative process, while tunneling from the neighboring sites constitutes the driving force. We characterize the emerging steady states of this atomtronic device. With increasing dissipation strength γ the system crosses from a superfluid state, characterized by a coherent Josephson current into the lossy site, to a resistive state, characterized by an incoherent hopping transport. For intermediate values of γ , the system exhibits bistability, where a superfluid and an incoherent branch coexist. We also study the relaxation dynamics towards the steady state, where we find a critical slowing down, indicating the presence of a nonequilibrium phase transition.

  13. Data-Driven Control of Refrigeration System

    DEFF Research Database (Denmark)

    Vinther, Kasper

    traditionally are a pressure and a temperature sensor. In this thesis, a novel maximum slope-seeking (MSS) control method is developed. This has resulted in a control implementation, which successfully has been able to control the evaporator superheat in four widely different refrigeration system test...... conditions make optimal tuning of controllers a difficult and time consuming task. These are also some of the challenges which make advanced model-based control difficult, and a model-based controller will often be tailored to a specific system. The focus in this thesis is therefore instead on development...... of data-driven control strategies with a higher plug and play potential. One of the main control challenges in refrigeration systems is proper control of superheat for efficient and safe operation of the system. This task can be performed by an electronic expansion valve and requires two sensors, which...

  14. Instability in electromagnetically driven flows Part I

    CERN Document Server

    Gissinger, Christophe; Fauve, Stephan

    2016-01-01

    The MHD flow driven by a travelling magnetic field (TMF) in an annular channel is investigated numerically. For sufficiently large magnetic Reynolds number Rm, or if a large enough pressure gradient is externally applied, the system undergoes an instability in which the flow rate in the channel dramatically drops from synchronism with the wave to much smaller velocities. This transition takes the form of a saddle-node bifurcation for the time-averaged quantities. In this first paper, we characterize the bifurcation, and study the stability of the flow as a function of several parameters. We show that the bifurcation of the flow involves a bistability between Poiseuille-like and Hartman-like regimes, and relies on magnetic flux expulsion. Based on this observation, new predictions are made for the occurrence of this stalling instability.

  15. Instability in electromagnetically driven flows Part II

    CERN Document Server

    Imazio, Paola Rodriguez

    2016-01-01

    In a previous paper, we have reported numerical simulations of the MHD flow driven by a travelling magnetic field (TMF) in an annular channel, at low Reynolds number. It was shown that the stalling of such induction pump is strongly related to magnetic flux expulsion. In the present article, we show that for larger hydrodynamic Reynolds number, and with more realistic boundary conditions, this instability takes the form of a large axisymmetric vortex flow in the (r,z)-plane, in which the fluid is locally pumped in the direction opposite to the one of the magnetic field. Close to the marginal stability of this vortex flow, a low-frequency pulsation is generated. Finally, these results are compared to theoretical predictions and are discussed within the framework of experimental annular linear induction electromagnetic pumps.

  16. 92 K thermoacoustically driven pulse tube refrigerator

    Institute of Scientific and Technical Information of China (English)

    TANG Ke; CHEN Guobang; JIN Tao; KONG Bo; BAO Rui; QIU Limin; GAN Zhihua

    2004-01-01

    @@ A thermoacoustic prime mover, instead of a mechanical compressor, was firstly proposed in 1990 by Radebaugh and Swift et al. to drive a pulse tube refrigerator [1]. The so-called thermoacoustically driven pulse tube refrigerator (TADPTR) has a number of advantages. First,it is characterized by its long-term stable operation for it has no moving components. Besides, solar energy and waste fuel gas can be adopted as its driving source. Utilization of low-grade energy not only improves its overall thermal efficiency, but also is most attractively applicable to the case which is short of electricity but abundant in heat energy. The potential applications, such as thermoacoustic natural gas liquefier, are under development[2].It burns part of natural gas to drive a pulse tube refrigerator whose cooling capacity is then used to liquefy the rest natural gas.

  17. Timing-Driven-Testable Convergent Tree Adders

    Directory of Open Access Journals (Sweden)

    Johnnie A. Huang

    2002-01-01

    Full Text Available Carry lookahead adders have been, over the years, implemented in complex arithmetic units due to their regular structure which leads to efficient VLSI implementation for fast adders. In this paper, timing-driven testability synthesis is first performed on a tree adder. It is shown that the structure of the tree adder provides for a high fanout with an imbalanced tree structure, which likely contributes to a racing effect and increases the delay of the circuit. The timing optimization is then realized by reducing the maximum fanout of the adder and by balancing the tree circuit. For a 56-b testable tree adder, the optimization produces a 6.37%increase in speed of the critical path while only contributing a 2.16% area overhead. The full testability of the circuit is achieved in the optimized adder design.

  18. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  19. Numerical Simulations of Driven Relativistic MHD Turbulence

    CERN Document Server

    Zrake, Jonathan

    2011-01-01

    A wide variety of astrophysical phenomena involve the flow of turbulent magnetized gas with relativistic velocity or energy density. Examples include gamma-ray bursts, active galactic nuclei, pulsars, magnetars, micro-quasars, merging neutron stars, X-ray binaries, some supernovae, and the early universe. In order to elucidate the basic properties of the relativistic magnetohydrodynamical (RMHD) turbulence present in these systems, we present results from numerical simulations of fully developed driven turbulence in a relativistically warm, weakly magnetized and mildly compressible ideal fluid. We have evolved the RMHD equations for many dynamical times on a uniform grid with 1024^3 zones using a high order Godunov code. We observe the growth of magnetic energy from a seed field through saturation at about 1% of the total fluid energy. We compute the power spectrum of velocity and density-weighted velocity and conclude that the inertial scaling is consistent with a slope of -5/3. We compute the longitudinal a...

  20. Statistical mechanics of driven diffusive systems

    CERN Document Server

    Schmittmann, B

    1995-01-01

    Far-from-equilibrium phenomena, while abundant in nature, are not nearly as well understood as their equilibrium counterparts. On the theoretical side, progress is slowed by the lack of a simple framework, such as the Boltzmann-Gbbs paradigm in the case of equilibrium thermodynamics. On the experimental side, the enormous structural complexity of real systems poses serious obstacles to comprehension. Similar difficulties have been overcome in equilibrium statistical mechanics by focusing on model systems. Even if they seem too simplistic for known physical systems, models give us considerable insight, provided they capture the essential physics. They serve as important theoretical testing grounds where the relationship between the generic physical behavior and the key ingredients of a successful theory can be identified and understood in detail. Within the vast realm of non-equilibrium physics, driven diffusive systems form a subset with particularly interesting properties. As a prototype model for these syst...

  1. Neutrino oscillations in magnetically driven supernova explosions

    CERN Document Server

    Kawagoe, Shio; Kotake, Kei

    2009-01-01

    We investigate neutrino oscillations from core-collapse supernovae that produce magnetohydrodynamic (MHD) explosions. By calculating numerically the flavor conversion of neutrinos in the highly non-spherical envelope, we study how the explosion anisotropy has impacts on the emergent neutrino spectra through the Mikheyev-Smirnov-Wolfenstein effect. In the case of the inverted mass hierarcy with a relatively large theta_(13), we show that survival probabilities of electron type neutrinos and antineutrinos seen from the rotational axis of the MHD supernovae (i.e., polar direction), can be significantly different from those along the equatorial direction. The event numbers of electron type antineutrinos observed from the polar direction are predicted to show steepest decrease, reflecting the passage of the magneto-driven shock to the so-called high-resonance regions. Furthermore we point out that such a shock effect, depending on the original neutrino spectra, appears also for the low-resonance regions, which lea...

  2. Datasheet Driven Silicon Carbide Power MOSFET Model

    Energy Technology Data Exchange (ETDEWEB)

    Mudholkar, M; Ahmed, S; Ericson, MN; Frank, SS; Britton, CL; Mantooth, HA

    2014-05-01

    A compact model for SiC Power MOSFETs is presented. The model features a physical description of the channel current and internal capacitances and has been validated for dc, CV, and switching characteristics with measured data from a 1200-V, 20-A SiC power MOSFET in a temperature range of 25 degrees C to 225 degrees C. The peculiar variation of on-state resistance with temperature for SiC power MOSFETs has also been demonstrated through measurements and accounted for in the developed model. In order to improve the user experience with the model, a new datasheet driven parameter extraction strategy has been presented which requires only data available in device datasheets, to enable quick parameter extraction for off-the-shelf devices. Excellent agreement is shown between measurement and simulation using the presented model over the entire temperature range.

  3. Datasheet driven silicon carbide power MOSFET model

    Energy Technology Data Exchange (ETDEWEB)

    Mudholkar, Mihir [Standard Products Group, Pheonix, AZ (United States); Ahmed, Shamin [Univ. of Arkansas, Fayetteville, AR (United States); Ericson, Milton Nance [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Frank, Steven Shane [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Britton Jr., Charles L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mantooth, H. Alan [Univ. of Arkansas, Fayetteville, AR (United States)

    2014-01-10

    A compact model for SiC Power MOSFETs is presented. The model features a physical description of the channel current and internal capacitances and has been validated for dc, CV, and switching characteristics with measured data from a 1200-V, 20-A SiC power MOSFET in a temperature range of 25 degrees C to 225 degrees C. The peculiar variation of on-state resistance with temperature for SiC power MOSFETs has also been demonstrated through measurements and accounted for in the developed model. In order to improve the user experience with the model, a new datasheet driven parameter extraction strategy has been presented which requires only data available in device datasheets, to enable quick parameter extraction for off-the-shelf devices. Excellent agreement is shown between measurement and simulation using the presented model over the entire temperature range.

  4. Quasiclassical dynamics of resonantly driven Rydberg states

    Energy Technology Data Exchange (ETDEWEB)

    Buchleitner, A. [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Sacha, K.; Zakrzewski, J. [Instytut Fizyki Imienia Mariana Smoluchowskiego, Uniwersytet Jagiellonski, Cracow (Poland); Delande, D. [Laboratoire Kastler-Brossel, Paris (France)

    1999-02-01

    We present a semiclassical analysis of the dynamics of Rydberg states of atomic hydrogen driven by a resonant microwave field of linear polarization. The semiclassical quasienergies of the atom in the field are found to be in very good agreement with the exact quantum solutions. The ionization rates of individual eigenstates of the atom dressed by the field reflect their quasiclassical dynamics along classical periodic orbits in the near integrable regime, but exhibit a transition to nonspecific rates when global chaos takes over in phase space. We concentrate both on the principal resonance where the unperturbed Kepler frequency {omega}{sub K}is equal to the driving field frequency {omega} and on the higher primary resonance {omega}=2{omega}{sub K}. The latter case allows for the construction of nondispersive wave packets which propagate along Kepler ellipses of intermediate eccentricity. (orig.) 37 refs.

  5. Model Driven Software Development for Agricultural Robotics

    DEFF Research Database (Denmark)

    Larsen, Morten

    2016-01-01

    The design and development of agricultural robots, consists of both mechan- ical, electrical and software components. All these components must be de- signed and combined such that the overall goal of the robot is fulfilled. The design and development of these systems require collaboration between...... processing, control engineering, etc. This thesis proposes a Model-Driven Software Develop- ment based approach to model, analyse and partially generate the software implementation of a agricultural robot. Furthermore, Guidelines for mod- elling the architecture of an agricultural robots are provided......, assisting with bridging the different engineering disciplines. Timing play an important role in agricultural robotic applications, synchronisation of robot movement and implement actions is important in order to achieve precision spraying, me- chanical weeding, individual feeding, etc. Discovering...

  6. Failure-probability driven dose painting

    Energy Technology Data Exchange (ETDEWEB)

    Vogelius, Ivan R.; Håkansson, Katrin; Due, Anne K.; Aznar, Marianne C.; Kristensen, Claus A.; Rasmussen, Jacob; Specht, Lena [Department of Radiation Oncology, Rigshospitalet, University of Copenhagen, Copenhagen 2100 (Denmark); Berthelsen, Anne K. [Department of Radiation Oncology, Rigshospitalet, University of Copenhagen, Copenhagen 2100, Denmark and Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen 2100 (Denmark); Bentzen, Søren M. [Department of Radiation Oncology, Rigshospitalet, University of Copenhagen, Copenhagen 2100, Denmark and Departments of Human Oncology and Medical Physics, University of Wisconsin, Madison, Wisconsin 53792 (United States)

    2013-08-15

    Purpose: To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning study using the optimized dose prescription in 20 patients is performed.Methods: Patients treated at our center have five tumor subvolumes from the center of the tumor (PET positive volume) and out delineated. The spatial distribution of 48 failures in patients with complete clinical response after (chemo)radiation is used to derive a model for tumor control probability (TCP). The total TCP is fixed to the clinically observed 70% actuarial TCP at five years. Additionally, the authors match the distribution of failures between the five subvolumes to the observed distribution. The steepness of the dose–response is extracted from the literature and the authors assume 30% and 20% risk of subclinical involvement in the elective volumes. The result is a five-compartment dose response model matching the observed distribution of failures. The model is used to optimize the distribution of dose in individual patients, while keeping the treatment intensity constant and the maximum prescribed dose below 85 Gy.Results: The vast majority of failures occur centrally despite the small volumes of the central regions. Thus, optimizing the dose prescription yields higher doses to the central target volumes and lower doses to the elective volumes. The dose planning study shows that the modified prescription is clinically feasible. The optimized TCP is 89% (range: 82%–91%) as compared to the observed TCP of 70%.Conclusions: The observed distribution of locoregional failures was used to derive an objective, data-driven dose prescription function. The optimized dose is predicted to result in a substantial increase in local control without increasing the predicted risk of toxicity.

  7. Indirectly driven targets for inertial confinement fusion

    International Nuclear Information System (INIS)

    The physics of indirectly driven targets for inertial confinement fusion - so called hohlraum targets - is investigated. Scaling relations for radiation heat waves in high-Z and low-Z materials are derived from one-dimensional multigroup simulation. A two-temperature model is developed for radiation cavities including fusion capsules. The efficiency of X-ray transfer to the capsule by multiple absorption and re-emission inside the cavity is obtained as a function of cavity areas and materials. Using gold for the cavity wall and carbon for the capsule ablator, transfer efficiencies between 50% and 33% are obtained for area ratios between 5 and 10, respectively. Also, the hydrodynamic efficiency of X-ray driven capsule implosion and the dependence of the implosion velocity on the hohlraum temperature are given analytically, derived from the rocket model. With carbon ablators, hydroefficiencies of up to 20% can be achieved. Under optimal conditions, an implosion velocity of 3 x 107 cm/s is reached with a temperature of about 210 eV of the capsule ablator and about 250 eV of the cavity wall. Assuming 70-90% conversion efficiency of beam energy into X-rays (not analysed in this paper), overall coupling efficiencies in the range of 5-10% seem to be possible. One-dimensional simulations of full reactor size targets (10MJ driver pulses) are presented. The model results compare well with the simulations. Limit in scaling down to smaller systems are discussed; the scaling relation for the required enhancement of implosion velocity and hohlraum temperature is derived. (author). 21 refs, 14 figs, 1 tab

  8. Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators

    Science.gov (United States)

    Chen, Xi; Goodnight, Davis; Gao, Zhenghan; Cavusoglu, Ahmet H.; Sabharwal, Nina; Delay, Michael; Driks, Adam; Sahin, Ozgur

    2015-06-01

    Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth's climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Here, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air-water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

  9. Family ethnic socialization and ethnic identity: a family-driven, youth-driven, or reciprocal process?

    Science.gov (United States)

    Umaña-Taylor, Adriana J; Zeiders, Katharine H; Updegraff, Kimberly A

    2013-02-01

    The current study examined the longitudinal associations between family ethnic socialization and youths' ethnic identity among a sample of Mexican-origin youth (N = 178, Mage = 18.17, SD = .46). Findings from multiple-group cross lagged panel models over a 2-year period indicated that for U.S.-born youth with immigrant parents, the process appeared to be family driven: Youths' perceptions of family ethnic socialization in late adolescence were associated with significantly greater ethnic identity exploration and resolution in emerging adulthood, while youths' ethnic identity during late adolescence did not significantly predict youths' future perceptions of family ethnic socialization. Conversely, for U.S.-born youth with U.S. born parents, youths' ethnic identity significantly predicted their future perceptions of family ethnic socialization but perceptions of family ethnic socialization did not predict future levels of youths' ethnic identity, suggesting a youth-driven process. Findings were consistent for males and females.

  10. Differentiating between marketing-driven and technology-driven vendors of medical information systems.

    Science.gov (United States)

    Friedman, B A; Mitchell, W; Singh, K

    1994-08-01

    Buyers of medical information systems such as laboratory information systems need to recognize that the vendors of such systems may pursue corporate strategies emphasizing expenditures on marketing and client services, expenditures on technology and research and development (R&D), or a more balanced approach. The strategic goals and objectives of a vendor of an information system should align closely with those of a potential hospital client. A restless hospital client seeking cutting-edge technology will probably be dissatisfied with a system vendor who emphasizes slow ongoing incremental system development. Objective criteria for distinguishing between a marketing-driven vendor and a technology-driven vendor of medical information systems, and their variants, are presented based on the ratio of marketing expenditures to sales revenue compared with the ratio of research and development expenditures to sales revenue of the company. More subjective narrative criteria are also offered for making such distinctions. PMID:8060224

  11. Automated Gesturing for Virtual Characters: Speech-driven and Text-driven Approaches

    Directory of Open Access Journals (Sweden)

    Goranka Zoric

    2006-04-01

    Full Text Available We present two methods for automatic facial gesturing of graphically embodied animated agents. In one case, conversational agent is driven by speech in automatic Lip Sync process. By analyzing speech input, lip movements are determined from the speech signal. Another method provides virtual speaker capable of reading plain English text and rendering it in a form of speech accompanied by the appropriate facial gestures. Proposed statistical model for generating virtual speaker’s facial gestures can be also applied as addition to lip synchronization process in order to obtain speech driven facial gesturing. In this case statistical model will be triggered with the input speech prosody instead of lexical analysis of the input text.

  12. A comparison of wake measurements in motor-driven and flow-driven turbine experiments

    Science.gov (United States)

    Araya, Daniel B.; Dabiri, John O.

    2015-07-01

    We present experimental data to compare and contrast the wake characteristics of a turbine whose rotation is either driven by the oncoming flow or prescribed by a motor. Velocity measurements are collected using two-dimensional particle image velocimetry in the near-wake region of a lift-based, vertical-axis turbine. The wake of this turbine is characterized by a spanwise asymmetric velocity profile which is found to be strongly dependent on the turbine tip speed ratio (TSR), while only weakly dependent on Reynolds number ( Re). For a given Re, the TSR is controlled either passively by a mechanical brake or actively by a DC motor. We find that there exists a finite region in TSR versus Re space where the wakes of the motor-driven turbine and flow-driven turbine are indistinguishable to within experimental precision. Outside of this region, the sign of the net circulation in the wake changes as TSR is increased by the motor. Shaft torque measurements show a corresponding sign change above this TSR threshold set by circulation, indicating a transition from net torque due to lift to net torque due to drag produced by the turbine blades, the latter of which can give wake measurements that are inconsistent with a flow-driven turbine. The results support the claim that the turbine kinematics and aerodynamic properties are the sole factors that govern the dynamics of its wake, irrespective of the means to move the turbine blades. This has significance for both experimental and computational studies where it may be necessary, or perhaps more economical, to prescribe the turbine kinematics in order to analyze its aerodynamic characteristics.

  13. A photochemically driven molecular-level abacus

    Science.gov (United States)

    Ashton; Ballardini; Balzani; Credi; Dress; Ishow; Kleverlaan; Kocian; Preece; Spencer; Stoddart; Venturi; Wenger

    2000-10-01

    A molecular-level abacus-like system driven by light inputs has been designed in the form of a [2]rotaxane, comprising the pi-electron-donating macrocyclic polyether bis-p-phenylene-34-crown-10 (BPP34C10) and a dumbbell-shaped component that contains 1) a Ru(II) polypyridine complex as one of its stoppers in the form of a photoactive unit, 2) a p-terphenyl-type ring system as a rigid spacer, 3) a 4,4'-bipyridinium unit and a 3,3'-dimethyl-4,4'-bipyridinium unit as pi-electron-accepting stations, and 4) a tetraarylmethane group as the second stopper. The synthesis of the [2]rotaxane was accomplished in four successive stages. First of all, the dumbbell-shaped component of the [2]rotaxane was constructed by using conventional synthetic methodology to make 1) the so-called "west-side" comprised of the Ru(II) polypyridine complex linked by a bismethylene spacer to the p-terphenyl-type ring system terminated by a benzylic bromomethyl function and 2) the so-called "east-side" comprised of the tetraarylmethane group, attached by a polyether linkage to the bipyridinium unit, itself joined in turn by a trismethylene spacer to an incipient 3,3'-dimethyl-4,4'-bipyridinium unit. Next, 3) the "west-side" and "east-side" were fused together by means of an alkylation to give the dumbbell-shaped compound, which was 4) finally subjected to a thermodynamically driven slippage reaction, with BPP34C10 as the ring, to afford the [2]rotaxane. The structure of this interlocked molecular compound was characterized by mass spectrometry and NMR spectroscopy, which also established, along with cyclic voltammetry, the co-conformational behavior of the molecular shuttle. The stable translational isomer is the one in which the BPP34C10 component encircles the 4,4'-bipyridinium unit, in keeping with the fact that this station is a better pi-electron acceptor than the other station. This observation raises the question- can the BPP34C10 macrocycle be made to shuttle between the two stations by a

  14. Numerical simulation of the gas driven fracture propagation

    International Nuclear Information System (INIS)

    The process of the gas driven fracture propagation has been studied. The mathematical model of this physical process has been proposed. The numerical algorithm has been developed and the mathematical simulation of the process of the gas driven fracture propagation has been performed

  15. Data-Driven Hint Generation from Peer Debugging Solutions

    Science.gov (United States)

    Liu, Zhongxiu

    2015-01-01

    Data-driven methods have been a successful approach to generating hints for programming problems. However, the majority of previous studies are focused on procedural hints that aim at moving students to the next closest state to the solution. In this paper, I propose a data-driven method to generate remedy hints for BOTS, a game that teaches…

  16. For whom the goals loom: Context-driven goal contagion

    NARCIS (Netherlands)

    Leander, N. Pontus; Shah, James Y.

    2013-01-01

    Goal contagion is a process in which perceivers inadvertently "catch" goals inferred from others' behavior; yet, social perception is often driven by the broader contexts surrounding others and these contexts may suffice to drive goal inferences and contagion on their own. In Study 1, context-driven

  17. Fokker-Planck/Transport model for neutral beam driven tokamaks

    International Nuclear Information System (INIS)

    The application of nonlinear Fokker-Planck models to the study of beam-driven plasmas is briefly reviewed. This evolution of models has led to a Fokker-Planck/Transport (FPT) model for neutral-beam-driven Tokamaks, which is described in detail. The FPT code has been applied to the PLT, PDX, and TFTR Tokamaks, and some representative results are presented

  18. Using Database-Driven Web Pages for Your Courses.

    Science.gov (United States)

    Sullivan, Peter

    1999-01-01

    Describes database-driven Web pages that dynamically display different information each time the page is accessed in response to the user's needs. Highlights include information management; online assignments; grade tracking; updating Web pages; creating database-driven Web pages; and examples of how they have been used for a high school physics…

  19. Discovery and analysis of e-mail-driven business processes

    NARCIS (Netherlands)

    Stuit, Marco; Wortmann, Hans

    2012-01-01

    E-mail is used as the primary tool for business communication and collaboration. This paper presents a novel e-mail interaction mining method to discover and analyze e-mail-driven business processes. An e-mail-driven business process is perceived as a human collaboration process that consists of int

  20. Process-driven architecture: design techniques and methods

    NARCIS (Netherlands)

    Jaskiewicz, T.

    2007-01-01

    This paper explores the notion of process-driven architecture and, as a consequence, application of complex systems in the newly defined area of digital process-driven architectural design in order to formulate a suitable design method. Protospace software environment and SwarmCAD software applicati

  1. Impact Forces from Tsunami-Driven Debris

    Science.gov (United States)

    Ko, H.; Cox, D. T.; Riggs, H.; Naito, C. J.; Kobayashi, M. H.; Piran Aghl, P.

    2012-12-01

    Debris driven by tsunami inundation flow has been known to be a significant threat to structures, yet we lack the constitutive equations necessary to predict debris impact force. The objective of this research project is to improve our understanding of, and predictive capabilities for, tsunami-driven debris impact forces on structures. Of special interest are shipping containers, which are virtually everywhere and which will float even when fully loaded. The forces from such debris hitting structures, for example evacuation shelters and critical port facilities such as fuel storage tanks, are currently not known. This research project focuses on the impact by flexible shipping containers on rigid columns and investigated using large-scale laboratory testing. Full-scale in-air collision experiments were conducted at Lehigh University with 20 ft shipping containers to experimentally quantify the nonlinear behavior of full scale shipping containers as they collide into structural elements. The results from the full scale experiments were used to calibrate computer models and used to design a series of simpler, 1:5 scale wave flume experiments at Oregon State University. Scaled in-air collision tests were conducted using 1:5 scale idealized containers to mimic the container behavior observed in the full scale tests and to provide a direct comparison to the hydraulic model tests. Two specimens were constructed using different materials (aluminum, acrylic) to vary the stiffness. The collision tests showed that at higher speeds, the collision became inelastic as the slope of maximum impact force/velocity decreased with increasing velocity. Hydraulic model tests were conducted using the 1:5 scaled shipping containers to measure the impact load by the containers on a rigid column. The column was instrumented with a load cell to measure impact forces, strain gages to measure the column deflection, and a video camera was used to provide the debris orientation and speed. The

  2. Accelerator-driven Transmutation of Waste

    Science.gov (United States)

    Venneri, Francesco

    1998-04-01

    Nuclear waste from commercial power plants contains large quantities of plutonium, other fissionable actinides, and long-lived fission products that are potential proliferation concerns and create challenges for the long-term storage. Different strategies for dealing with nuclear waste are being followed by various countries because of their geologic situations and their views on nuclear energy, reprocessing and non-proliferation. The current United States policy is to store unprocessed spent reactor fuel in a geologic repository. Other countries are opting for treatment of nuclear waste, including partial utilization of the fissile material contained in the spent fuel, prior to geologic storage. Long-term uncertainties are hampering the acceptability and eventual licensing of a geologic repository for nuclear spent fuel in the US, and driving up its cost. The greatest concerns are with the potential for radiation release and exposure from the spent fuel for tens of thousands of years and the possible diversion and use of the actinides contained in the waste for weapons construction. Taking advantage of the recent breakthroughs in accelerator technology and of the natural flexibility of subcritical systems, the Accelerator-driven Transmutation of Waste (ATW) concept offers the United States and other countries the possibility to greatly reduce plutonium, higher actinides and environmentally hazardous fission products from the waste stream destined for permanent storage. ATW does not eliminate the need for, but instead enhances the viability of permanent waste repositories. Far from being limited to waste destruction, the ATW concept also brings to the table new technologies that could be relevant for next-generation power producing reactors. In the ATW concept, spent fuel would be shipped to the ATW site where the plutonium, transuranics and selected long-lived fission products would be destroyed by fission or transmutation in their first and only pass through the

  3. Image-driven pharmacokinetics: nanomedicine concentration across space and time.

    Science.gov (United States)

    Brill, Dab A; MacKay, J Andrew

    2015-01-01

    Clinical pharmacokinetics (PK) primarily measures the concentration of drugs in the blood. For nanomedicines it may be more relevant to determine concentration within a target tissue. The emerging field of image-driven PK, which utilizes clinically accepted molecular imaging technology, empirically and noninvasively, measures concentration in multiple tissues. Image-driven PK represents the intersection of PK and biodistribution, combining to provide models of concentration across space and time. Image-driven PK can be used both as a research tool and in the clinic. This review explores the history of pharmacokinetics, technologies used in molecular imaging (especially positron emission tomography) and research using image-driven pharmacokinetic analysis. When standardized, image-driven PK may have significant implications in preclinical development as well as clinical optimization of targeted nanomedicines.

  4. Performance Modeling and Evaluation for Information-Driven Networks

    CERN Document Server

    Wu, Kui; Hu, Guoqiang

    2008-01-01

    Information-driven networks include a large category of networking systems, where network nodes are aware of information delivered and thus can not only forward data packets but may also perform information processing. In many situations, the quality of service (QoS) in information-driven networks is provisioned with the redundancy in information. Traditional performance models generally adopt evaluation measures suitable for packet-oriented service guarantee, such as packet delay, throughput, and packet loss rate. These performance measures, however, do not align well with the actual need of information-driven networks. New performance measures and models for information-driven networks, despite their importance, have been mainly blank, largely because information processing is clearly application dependent and cannot be easily captured within a generic framework. To fill the vacancy, we present a new performance evaluation framework particularly tailored for information-driven networks, based on the recent ...

  5. The Exploration of Design Driven Innovation as a Dynamic Capability

    Directory of Open Access Journals (Sweden)

    Philips Kembaren

    2012-01-01

    Full Text Available Innovation enables companies to attain consistent organic growth that brings benefits to stakeholders. Designthinking approach in innovation has been emergent to be an alternative to technological development path inorder to generate competitive and successful product or service in the market place. Design driven innovationcombines functional and semantic dimensions of products or services in the marketplace. Previous researchhas recently revealed practices of design driven innovation in various industries. However, little is known tothe extent that companies in Indonesia practicing design driven innovation. A theoretical framework withperspective from dynamic capability theoretical lens and guided by Dubin’s theory building methodology isproposed to explain the constructs and role of design in the process of innovation. The research is expected tocontribute a new construct to the existing framework, namely construct that related to how we could assessthe value of the design-driven innovation output, perceived by the costumers.Keywords: design driven innovation, dynamic capabilities, theory building

  6. Spontaneous Capillarity-Driven Droplet Ejection

    CERN Document Server

    Wollman, Andrew; Pettit, Donald; Weislogel, Mark

    2012-01-01

    The first large length-scale capillary rise experiments were conducted by R. Siegel using a drop tower at NASA LeRC shortly after the 1957 launch of Sputnik I. Siegel was curious if the wetting fluid would expel from the end of short capillary tubes in a low-gravity environment. He observed that although the fluid partially left the tubes, it was always pulled back by surface tension, which caused the fluid to remain pinned to the tubes' end. By exploiting tube geometry and fluid properties, we demonstrate that such capillary flows can in fact eject a variety of jets and drops. This fluid dynamics video provides a historical overview of such spontaneous capillarity-driven droplet ejection. Footage of terrestrial and low earth orbit experiments are also shown. Droplets generated in a microgravity environment are $10^6$ times larger than those ejected in a terrestrial environment. The accompanying article provides a summary of the critical parameters and experimental procedures. Scaling the governing equations ...

  7. Shear-Driven Reconnection in Kinetic Models

    Science.gov (United States)

    Black, C.; Antiochos, S. K.; Germaschewski, K.; Karpen, J. T.; DeVore, C. R.; Bessho, N.

    2015-12-01

    The explosive energy release in solar eruptive phenomena is believed to be due to magnetic reconnection. In the standard model for coronal mass ejections (CME) and/or solar flares, the free energy for the event resides in the strongly sheared magnetic field of a filament channel. The pre-eruption force balance consists of an upward force due to the magnetic pressure of the sheared field countered by a downward tension due to overlying unsheared field. Magnetic reconnection disrupts this force balance; therefore, it is critical for understanding CME/flare initiation, to model the onset of reconnection driven by the build-up of magnetic shear. In MHD simulations, the application of a magnetic-field shear is a trivial matter. However, kinetic effects are dominant in the diffusion region and thus, it is important to examine this process with PIC simulations as well. The implementation of such a driver in PIC methods is challenging, however, and indicates the necessity of a true multiscale model for such processes in the solar environment. The field must be sheared self-consistently and indirectly to prevent the generation of waves that destroy the desired system. Plasma instabilities can arise nonetheless. In the work presented here, we show that we can control this instability and generate a predicted out-of-plane magnetic flux. This material is based upon work supported by the National Science Foundation under Award No. AGS-1331356.

  8. Planck driven by vision, broken by war

    CERN Document Server

    Brown, Brandon R

    2015-01-01

    Planck's Law, an equation used by physicists to determine the radiation leaking from any object in the universe, was described by Albert Einstein as "the basis of all twentieth-century physics." Max Planck is credited with being the father of quantum theory, and his work laid the foundation for our modern understanding of matter and energetic processes. But Planck's story is not well known, especially in the United States. A German physicist working during the first half of the twentieth century, his library, personal journals, notebooks, and letters were all destroyed with his home in World War II. What remains, other than his contributions to science, are handwritten letters in German shorthand, and tributes from other scientists of the time, including his close friend Albert Einstein. In Planck: Driven by Vision, Broken by War, Brandon R. Brown interweaves the voices and writings of Planck, his family, and his contemporaries-with many passages appearing in English for the first time-to create a portrait of...

  9. Synthesizing Performance-driven Facial Animation

    Institute of Scientific and Technical Information of China (English)

    LUO Chang-Wei; YU Jun; WANG Zeng-Fu

    2014-01-01

    In this paper, we present a system for real-time performance-driven facial animation. With the system, the user can control the facial expression of a digital character by acting out the desired facial action in front of an ordinary camera. First, we create a muscle-based 3D face model. The muscle actuation parameters are used to animate the face model. To increase the reality of facial animation, the orbicularis oris in our face model is divided into the inner part and outer part. We also establish the relationship between jaw rotation and facial surface deformation. Second, a real-time facial tracking method is employed to track the facial features of a performer in the video. Finally, the tracked facial feature points are used to estimate muscle actuation parameters to drive the face model. Experimental results show that our system runs in real time and outputs realistic facial animations. Compared with most existing performance-based facial animation systems, ours does not require facial markers, intrusive lighting, or special scanning equipment, thus it is inexpensive and easy to use.

  10. Subcritical reactivity monitoring in accelerator driven systems

    International Nuclear Information System (INIS)

    In this paper, an absolute measurements technique for the subcriticality determination is presented. The development of accelerator driven systems (ADS) requires the development of methods to monitor and control the subcriticality of this kind of system, without interfering with its normal operation mode. This method is based on the stochastic neutron and photon transport theory that can be implemented by presently available neutron transport codes. As a by-product of the methodology a monitoring measurement technique has been developed and verified using two coupled Monte Carlo programs. The first one, LAHET, simulates the spallation collisions and the high energy transport and the other, MCNPDSP, is used to estimate the counting statistics from neutron ray counter in fissile system, and the transport for neutrons with energies less than 20 Mev. Through the analysis of the counter detectors it is possible to determine the kinetics parameters and the keff value. We present two different ways to obtain these parameters using the accelerator or using a Cf-252 source. A good agreement between theory and simulations has been obtained with both sources

  11. Collision Statistics of Driven Polydisperse Granular Gases

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-Yuan; ZHANG Duan-Ming; LI Zhong-Ming; YANG Feng-Xia; GUO Xin-Ping

    2008-01-01

    We present a dynamicai model of two-dimensional polydisperse granular gases with fractal size distribution, in which the disks are subject to inelastic mutual collisions and driven by standard white noise. The inhomogeneity of the disk size distribution can be measured by a fractal dimension df. By Monte Carlo simulations, we have mainly investigated the effect of the inhomogeneity on the statistical properties of the system in the same inelasticity case. Some novel results are found that the average energy of the system decays exponentiaUy with a tendency to achieve a stable asymptotic value, and the system finally reaches a nonequilibrium steady state after a long evolution time. Furthermore, the inhomogeneity has great influence on the steady-state statisticai properties. With the increase of the fractal dimension df, the distributions of path lengths and free times between collisions deviate more obviously from expected theoretical forms for elastic spheres and have an overpopulation of short distances and time bins. The collision rate increases with df, but it is independent of time. Meanwhile, the velocity distribution deviates more strongly from the Gaussian one, but does not demonstrate any apparent universal behavior.

  12. Field-driven dynamics of nematic microcapillaries

    Science.gov (United States)

    Khayyatzadeh, Pouya; Fu, Fred; Abukhdeir, Nasser Mohieddin

    2015-12-01

    Polymer-dispersed liquid-crystal (PDLC) composites long have been a focus of study for their unique electro-optical properties which have resulted in various applications such as switchable (transparent or translucent) windows. These composites are manufactured using desirable "bottom-up" techniques, such as phase separation of a liquid-crystal-polymer mixture, which enable production of PDLC films at very large scales. LC domains within PDLCs are typically spheroidal, as opposed to rectangular for an LCD panel, and thus exhibit substantially different behavior in the presence of an external field. The fundamental difference between spheroidal and rectangular nematic domains is that the former results in the presence of nanoscale orientational defects in LC order while the latter does not. Progress in the development and optimization of PDLC electro-optical properties has progressed at a relatively slow pace due to this increased complexity. In this work, continuum simulations are performed in order to capture the complex formation and electric field-driven switching dynamics of approximations of PDLC domains. Using a simplified elliptic cylinder (microcapillary) geometry as an approximation of spheroidal PDLC domains, the effects of geometry (aspect ratio), surface anchoring, and external field strength are studied through the use of the Landau-de Gennes model of the nematic LC phase.

  13. Surface Tension Driven Convection Experiment (STDCE)

    Science.gov (United States)

    Ostrach, S.; Kamotani, Y.

    1996-01-01

    This document reports the results obtained from the Surface Tension Driven Convection Experiment (STDCE) conducted aboard the USML-1 Spacelab in 1992. The experiments used 10 cSt silicone oil placed in an open circular container that was 10 cm wide and 5 cm deep. Thermocapillary flow was induced by using either a cylindrical heater placed along the container centerline or by a CO2 laser. The tests were conducted under various power settings, laser beam diameters, and free surface shapes. Thermistors located at various positions in the test section recorded the temperature of the fluid, heater, walls, and air. An infrared imager was used to measure the free surface temperature. The flow field was studied by flow visualization and the data was analyzed by a PTV technique. The results from the flow visualization and the temperature measurements are compared with the numerical analysis that was conducted in conjunction with the experiment. The compared results include the experimental and numerical velocity vector plots, the streamline plots, the fluid temperature, and the surface temperature distribution.

  14. Latitudinal libration driven flows in triaxial ellipsoids

    CERN Document Server

    Vantieghem, S; Noir, J

    2015-01-01

    Motivated by understanding the liquid core dynamics of tidally deformed planets and moons, we present a study of incompressible flow driven by latitudinal libration within rigid triaxial ellipsoids. We first derive a laminar solution for the inviscid equations of motion under the assumption of uniform vorticity flow. This solution exhibits a res- onance if the libration frequency matches the frequency of the spin-over inertial mode. Furthermore, we extend our model by introducing a reduced model of the effect of viscous Ekman layers in the limit of low Ekman number (Noir and C\\`ebron 2013). This theoretical approach is consistent with the results of Chan et al. (2011) and Zhang et al. (2012) for spheroidal geometries. Our results are validated against systematic three-dimensional numerical simulations. In the second part of the paper, we present the first linear sta- bility analysis of this uniform vorticity flow. To this end, we adopt different methods (Lifschitz and Hameiri 1991; Gledzer and Ponomarev 1977)...

  15. Combining engineering and data-driven approaches

    DEFF Research Database (Denmark)

    Fischer, Katharina; De Sanctis, Gianluca; Kohler, Jochen;

    2015-01-01

    Two general approaches may be followed for the development of a fire risk model: statistical models based on observed fire losses can support simple cost-benefit studies but are usually not detailed enough for engineering decision-making. Engineering models, on the other hand, require many assump...... to the calibration of a generic fire risk model for single family houses to Swiss insurance data. The example demonstrates that the bias in the risk estimation can be strongly reduced by model calibration.......Two general approaches may be followed for the development of a fire risk model: statistical models based on observed fire losses can support simple cost-benefit studies but are usually not detailed enough for engineering decision-making. Engineering models, on the other hand, require many...... assumptions that may result in a biased risk assessment. In two related papers we show how engineering and data-driven modelling can be combined by developing generic risk models that are calibrated to statistical data on observed fire events. The focus of the present paper is on the calibration procedure...

  16. Solar-driven high temperature radiant cooling

    Institute of Scientific and Technical Information of China (English)

    SONG ZhaoPei; WANG RuZhu; ZHAI XiaoQiang

    2009-01-01

    Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller's COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%.According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion.

  17. Query-Driven Visualization and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruebel, Oliver; Bethel, E. Wes; Prabhat, Mr.; Wu, Kesheng

    2012-11-01

    This report focuses on an approach to high performance visualization and analysis, termed query-driven visualization and analysis (QDV). QDV aims to reduce the amount of data that needs to be processed by the visualization, analysis, and rendering pipelines. The goal of the data reduction process is to separate out data that is "scientifically interesting'' and to focus visualization, analysis, and rendering on that interesting subset. The premise is that for any given visualization or analysis task, the data subset of interest is much smaller than the larger, complete data set. This strategy---extracting smaller data subsets of interest and focusing of the visualization processing on these subsets---is complementary to the approach of increasing the capacity of the visualization, analysis, and rendering pipelines through parallelism. This report discusses the fundamental concepts in QDV, their relationship to different stages in the visualization and analysis pipelines, and presents QDV's application to problems in diverse areas, ranging from forensic cybersecurity to high energy physics.

  18. Entropic fluctuations in thermally driven harmonic networks

    CERN Document Server

    Jaksic, Vojkan; Shirikyan, Armen

    2016-01-01

    We consider a general network of harmonic oscillators driven out of thermal equilibrium by coupling to several heat reservoirs at different temperatures. The action of the reservoirs is implemented by Langevin forces. Assuming the existence and uniqueness of the steady state of the resulting process, we construct a canonical entropy production functional which satisfies the Gallavotti--Cohen fluctuation theorem, i.e., a global large deviation principle with a rate function I(s) obeying the Gallavotti--Cohen fluctuation relation I(-s)-I(s)=s for all s. We also consider perturbations of our functional by quadratic boundary terms and prove that they satisfy extended fluctuation relations, i.e., a global large deviation principle with a rate function that typically differs from I(s) outside a finite interval. This applies to various physically relevant functionals and, in particular, to the heat dissipation rate of the network. Our approach relies on the properties of the maximal solution of a one-parameter famil...

  19. Magnetohydrodynamic stability of stochastically driven accretion flows.

    Science.gov (United States)

    Nath, Sujit Kumar; Mukhopadhyay, Banibrata; Chattopadhyay, Amit K

    2013-07-01

    We investigate the evolution of magnetohydrodynamic (or hydromagnetic as coined by Chandrasekhar) perturbations in the presence of stochastic noise in rotating shear flows. The particular emphasis is the flows whose angular velocity decreases but specific angular momentum increases with increasing radial coordinate. Such flows, however, are Rayleigh stable but must be turbulent in order to explain astrophysical observed data and, hence, reveal a mismatch between the linear theory and observations and experiments. The mismatch seems to have been resolved, at least in certain regimes, in the presence of a weak magnetic field, revealing magnetorotational instability. The present work explores the effects of stochastic noise on such magnetohydrodynamic flows, in order to resolve the above mismatch generically for the hot flows. We essentially concentrate on a small section of such a flow which is nothing but a plane shear flow supplemented by the Coriolis effect, mimicking a small section of an astrophysical accretion disk around a compact object. It is found that such stochastically driven flows exhibit large temporal and spatial autocorrelations and cross-correlations of perturbation and, hence, large energy dissipations of perturbation, which generate instability. Interestingly, autocorrelations and cross-correlations appear independent of background angular velocity profiles, which are Rayleigh stable, indicating their universality. This work initiates our attempt to understand the evolution of three-dimensional hydromagnetic perturbations in rotating shear flows in the presence of stochastic noise.

  20. A quasilinear formulation of turbulence driven current

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, C. J.; Tang, Xian-Zhu; Guo, Zehua [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-02-15

    Non-inductive current drive mechanisms, such as the familiar neoclassical bootstrap current correspond to an essential component to the realization of steady state tokamak operation. In this work, we discuss a novel collisionless mechanism through which a mean plasma current may be driven in the presence of microturbulence. In analogy with the traditional neoclassical bootstrap current drive mechanism, in which the collisional equilibrium established between trapped and passing electrons results in the formation of a steady state plasma current, here we show that resonant scattering of electrons by drift wave microturbulence provides an additional means of determining the equilibrium between trapped and passing electrons. The resulting collisionless equilibrium is shown to result in the formation of an equilibrium current whose magnitude is a function of the thermodynamic forces. A mean field formulation is utilized to incorporate the above components into a unified framework through which both collisional as well as collisionless current drive mechanisms may be self-consistently treated. Utilizing a linearized Fokker-Planck collision operator, the plasma current in the presence of both collisions as well as turbulent stresses is computed, allowing for the relative strength of these two mechanisms to be quantified as a function of collisionality and fluctuation amplitude.

  1. A quasilinear formulation of turbulence driven current

    Science.gov (United States)

    McDevitt, C. J.; Tang, Xian-Zhu; Guo, Zehua

    2014-02-01

    Non-inductive current drive mechanisms, such as the familiar neoclassical bootstrap current correspond to an essential component to the realization of steady state tokamak operation. In this work, we discuss a novel collisionless mechanism through which a mean plasma current may be driven in the presence of microturbulence. In analogy with the traditional neoclassical bootstrap current drive mechanism, in which the collisional equilibrium established between trapped and passing electrons results in the formation of a steady state plasma current, here we show that resonant scattering of electrons by drift wave microturbulence provides an additional means of determining the equilibrium between trapped and passing electrons. The resulting collisionless equilibrium is shown to result in the formation of an equilibrium current whose magnitude is a function of the thermodynamic forces. A mean field formulation is utilized to incorporate the above components into a unified framework through which both collisional as well as collisionless current drive mechanisms may be self-consistently treated. Utilizing a linearized Fokker-Planck collision operator, the plasma current in the presence of both collisions as well as turbulent stresses is computed, allowing for the relative strength of these two mechanisms to be quantified as a function of collisionality and fluctuation amplitude.

  2. Field-driven dynamics of nematic microcapillaries.

    Science.gov (United States)

    Khayyatzadeh, Pouya; Fu, Fred; Abukhdeir, Nasser Mohieddin

    2015-12-01

    Polymer-dispersed liquid-crystal (PDLC) composites long have been a focus of study for their unique electro-optical properties which have resulted in various applications such as switchable (transparent or translucent) windows. These composites are manufactured using desirable "bottom-up" techniques, such as phase separation of a liquid-crystal-polymer mixture, which enable production of PDLC films at very large scales. LC domains within PDLCs are typically spheroidal, as opposed to rectangular for an LCD panel, and thus exhibit substantially different behavior in the presence of an external field. The fundamental difference between spheroidal and rectangular nematic domains is that the former results in the presence of nanoscale orientational defects in LC order while the latter does not. Progress in the development and optimization of PDLC electro-optical properties has progressed at a relatively slow pace due to this increased complexity. In this work, continuum simulations are performed in order to capture the complex formation and electric field-driven switching dynamics of approximations of PDLC domains. Using a simplified elliptic cylinder (microcapillary) geometry as an approximation of spheroidal PDLC domains, the effects of geometry (aspect ratio), surface anchoring, and external field strength are studied through the use of the Landau-de Gennes model of the nematic LC phase. PMID:26764713

  3. Magnetically driven accretion in protoplanetary discs

    CERN Document Server

    Simon, Jacob B; Kunz, Matthew W; Armitage, Philip J

    2015-01-01

    We characterize magnetically driven accretion at radii between 1 au and 100 au in protoplanetary discs, using a series of local non-ideal magnetohydrodynamic (MHD) simulations. The simulations assume a Minimum Mass Solar Nebula (MMSN) disc that is threaded by a net vertical magnetic field of specified strength. Confirming previous results, we find that the Hall effect has only a modest impact on accretion at 30 au, and essentially none at 100 au. At 1-10 au the Hall effect introduces a pronounced bi-modality in the accretion process, with vertical magnetic fields aligned to the disc rotation supporting a strong laminar Maxwell stress that is absent if the field is anti-aligned. In the anti-aligned case, we instead find evidence for bursts of turbulent stress at 5-10 au, which we tentatively identify with the non-axisymmetric Hall-shear instability. The presence or absence of these bursts depends upon the details of the adopted chemical model, which suggests that appreciable regions of actual protoplanetary di...

  4. Modelling materials driven far from equilibrium

    International Nuclear Information System (INIS)

    Materials driven from equilibrium offer a challenging field for both time and space multi-scale modelling. In materials under irradiation the elementary damaging process, that is, the nuclear collision leading to the displacement cascade, is modelled by molecular dynamics (∼10 ps, 10'3 nm'3), whereas the later stage recovery process is modelled by kinetic Monte Carlo (∼years, 10'4 nm'3); at still a coarser scale, grain boundary segregations are modelled by a mean field approximation of the very same atomistic model as used in kinetic Monte Carlo modelling. Connecting this broad range of time scales helps to elucidate basic issues on the criteria for alloy stability under irradiation. Irradiation effects on plasticity are beginning to be modelled in the same spirit; a first molecular dynamics study of the interaction of cascade debris with gliding dislocations has been reported together with the first results of mesoscale modelling of dislocation dynamics in the course of a nano-indentation test. Such studies can be extended to materials processed by ball milling

  5. How surfactants influence evaporation-driven flows

    Science.gov (United States)

    Liepelt, Robert; Marin, Alvaro; Rossi, Massimiliano; Kähler, Christian J.

    2014-11-01

    Capillary flows appear spontaneously in sessile evaporating drops and give rise to particle accumulation around the contact lines, commonly known as coffee-stain effect (Deegan et al., Nature, 1997). On the other hand, out-of-equilibrium thermal effects may induce Marangoni flows in the droplet's surface that play an important role in the flow patterns and in the deposits left on the substrate. Some authors have argued that contamination or the presence of surfactants might reduce or eventually totally annul the Marangoni flow (Hu & Larson, J. Phys. Chem. B, 2006). On the contrary, others have shown an enhancement of the reverse surface flow (Sempels et al., Nat. Commun., 2012). In this work, we employ Astigmatic Particle Tracking Velocimetry (APTV) to obtain the 3D3C evaporation-driven flow in both bulk and droplet's surface, using surfactants of different ionic characters and solubility. Our conclusions lead to a complex scenario in which different surfactants and concentrations yield very different surface-flow patterns, which eventually might influence the colloidal deposition patterns.

  6. Ecology-driven stereotypes override race stereotypes.

    Science.gov (United States)

    Williams, Keelah E G; Sng, Oliver; Neuberg, Steven L

    2016-01-12

    Why do race stereotypes take the forms they do? Life history theory posits that features of the ecology shape individuals' behavior. Harsh and unpredictable ("desperate") ecologies induce fast strategy behaviors such as impulsivity, whereas resource-sufficient and predictable ("hopeful") ecologies induce slow strategy behaviors such as future focus. We suggest that individuals possess a lay understanding of ecology's influence on behavior, resulting in ecology-driven stereotypes. Importantly, because race is confounded with ecology in the United States, we propose that Americans' stereotypes about racial groups actually reflect stereotypes about these groups' presumed home ecologies. Study 1 demonstrates that individuals hold ecology stereotypes, stereotyping people from desperate ecologies as possessing faster life history strategies than people from hopeful ecologies. Studies 2-4 rule out alternative explanations for those findings. Study 5, which independently manipulates race and ecology information, demonstrates that when provided with information about a person's race (but not ecology), individuals' inferences about blacks track stereotypes of people from desperate ecologies, and individuals' inferences about whites track stereotypes of people from hopeful ecologies. However, when provided with information about both the race and ecology of others, individuals' inferences reflect the targets' ecology rather than their race: black and white targets from desperate ecologies are stereotyped as equally fast life history strategists, whereas black and white targets from hopeful ecologies are stereotyped as equally slow life history strategists. These findings suggest that the content of several predominant race stereotypes may not reflect race, per se, but rather inferences about how one's ecology influences behavior.

  7. Photonic Crystal Laser-Driven Accelerator Structures

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  8. Nuclear Powered Laser Driven Plasma Propulsion System

    Science.gov (United States)

    Kammash, T.

    A relativistic plasma thruster that could open up the solar system to near-term human exploration is presented. It is based on recent experimental and theoretical research, which show that ultrafast (very short pulse length) lasers can accelerate charged particles to relativistic speeds. In table top-type experiments charge-neutral proton beams containing more than 1014 particles with mean energies of tens of MeV's have been produced when high intensity lasers with femtosecond (10-15 s) pulse lengths are made to strike thin solid targets. When viewed from a propulsion standpoint such systems can produce specific impulses of several million seconds albeit at modest thrusts and require nuclear power systems to drive them. Several schemes are proposed to enhance the thrust and make these systems suitable for manned interplanetary missions. In this paper we set forth the physics principles that make relativistic plasma driven by ultrafast lasers particularly attractive for propulsion applications. We introduce the “Laser Accelerated Plasma Propulsion System” LAPPS, and demonstrate its potential propulsive capability by addressing an interstellar mission to the Oort Cloud, and a planetary mission to Mars. We show that the first can be carried out in a human's lifetime and the second in a matter of months. In both instances we identify the major technological problems that must be addressed if this system is to evolve into a leading contender among the advance propulsion concepts currently under consideration.

  9. Data-Driven Detection of Prominent Objects.

    Science.gov (United States)

    Rodriguez-Serrano, Jose A; Larlus, Diane; Dai, Zhenwen

    2016-10-01

    This article deals with the detection of prominent objects in images. As opposed to the standard approaches based on sliding windows, we study a fundamentally different solution by formulating the supervised prediction of a bounding box as an image retrieval task. Indeed, given a global image descriptor, we find the most similar images in an annotated dataset, and transfer the object bounding boxes. We refer to this approach as data-driven detection (DDD). Our key novelty is to design or learn image similarities that explicitly optimize some aspect of the transfer unlike previous work which uses generic representations and unsupervised similarities. In a first variant, we explicitly learn to transfer, by adapting a metric learning approach to work with image and bounding box pairs. Second, we use a representation of images as object probability maps computed from low-level patch classifiers. Experiments show that these two contributions yield in some cases comparable or better results than standard sliding window detectors - despite its conceptual simplicity and run-time efficiency. Our third contribution is an application of prominent object detection, where we improve fine-grained categorization by pre-cropping images with the proposed approach. Finally, we also extend the proposed approach to detect multiple parts of rigid objects. PMID:26700971

  10. Miniaturized Air-Driven Planar Magnetic Generators

    Directory of Open Access Journals (Sweden)

    Jingjing Zhao

    2015-10-01

    Full Text Available This paper presents the design, analysis, fabrication and testing of two miniaturized air-driven planar magnetic generators. In order to reduce the magnetic resistance torque, Generator 1 establishes a static magnetic field by consisting a multilayer planar coil as the stator and two multi-pole permanent-magnet (PM rotors on both sides of the coil. To further decrease the starting torque and save more space, Generator 2 adopts the multilayer planar coil as the rotor and the multi-pole PMs as the stator, eliminating the casing without compromising the magnetic structure or output performance. The prototypes were tested gathering energy from wind which can work at a low wind speed of 1~2 m/s. Prototype of Generator 1 is with a volume of 2.61 cm3 and its normalized voltage reaches 485 mV/krpm. Prototype of Generator 2 has a volume of 0.92 cm3 and a normalized voltage as high as 538 mV/krpm. Additionally, output voltage can be estimated at better than 96% accuracy by the theoretical model developed in this paper. The two micro generators are capable of producing substantial electricity with little volume to serve as compact power conversion devices.

  11. Quantifying Supernovae-Driven Multiphase Galactic Outflows

    CERN Document Server

    Li, Miao; Ostriker, Jeremiah P

    2016-01-01

    Galactic outflows are ubiquitously observed in star-forming disk galaxies and are critical for galaxy formation. Supernovae (SNe) play the key role in driving the outflows, but there is no consensus as to how much energy, mass and metal they can launch out of the disk. We perform 3D, high-resolution hydrodynamic simulations to study SNe-driven outflows from stratified media. Assuming SN rate scales with gas surface density $\\Sigma_{\\rm{gas}}$ as in the Kennicutt-Schmidt (KS) relation, we find the mass loading factor, defined as the mass outflow flux divided by the star formation surface density, decreases with increasing $\\Sigma_{\\rm{gas}}$ as $\\propto \\Sigma^{-0.61}_{\\rm{gas}}$. Approximately $\\Sigma_{\\rm{gas}} \\lesssim$ 50 $M_\\odot/pc^2$ marks when the mass loading factor $\\gtrsim$1. About 10-50\\% of the energy and 40-80\\% of the metals produced by SNe end up in the outflows. The tenuous hot phase ($T>3\\times 10^5$ K) carries the majority of the energy and metals in outflows. We discuss how various physical...

  12. Computational dynamics of acoustically driven microsphere systems.

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  13. Ferromagnetic resonance driven by spin transfer torque

    Energy Technology Data Exchange (ETDEWEB)

    Staudacher, T.; Tsoi, M., E-mail: tsoi@physics.utexas.edu

    2011-09-30

    We study spin-torque-driven ferromagnetic resonance (ST-FMR) in point contacts. Point contacts as small as a few nanometers in size are used to inject microwave currents into F/N/F spin valves where two ferromagnetic (F) layers are separated by a nonmagnetic (N) metal spacer. High densities of injected currents produce the spin-transfer torque on magnetic moments and drive FMR in the F-layers. The resonance is detected electrically when a small rectified dc voltage appears across the point contact. Here we focus on the origin of this rectified signal and study ST-FMR in point contacts to spin valves with different ferromagnets (Py and Co) and single ferromagnetic (Py) films, as well as in spin-valve wires patterned by electron beam lithography. We find that this voltage can be explained by the resistance variations which originate from giant magnetoresistance in point contacts to spin valves and involve effects of anisotropic magnetoresistance and extraordinary Hall effect on the propagation of microwave currents in continuous F-films and microwires.

  14. Ultrafast electronic dynamics driven by nuclear motion

    Science.gov (United States)

    Vendrell, Oriol

    2016-05-01

    The transfer of electrical charge on a microscopic scale plays a fundamental role in chemistry, in biology, and in technological applications. In this contribution, we will discuss situations in which nuclear motion plays a central role in driving the electronic dynamics of photo-excited or photo-ionized molecular systems. In particular, we will explore theoretically the ultrafast transfer of a double electron hole between the functional groups of glycine after K-shell ionization and subsequent Auger decay. Although a large energy gap of about 15 eV initially exists between the two electronic states involved and coherent electronic dynamics play no role in the hole transfer, we will illustrate how the double hole can be transferred within 3 to 4 fs between both functional ends of the glycine molecule driven solely by specific nuclear displacements and non-Born-Oppenheimer effects. This finding challenges the common wisdom that nuclear dynamics of the molecular skeleton are unimportant for charge transfer processes at the few-femtosecond time scale and shows that they can even play a prominent role. We thank the Hamburg Centre for Ultrafast Imaging and the Volkswagen Foundation for financial support.

  15. Spin-current-driven thermoelectric coating.

    Science.gov (United States)

    Kirihara, Akihiro; Uchida, Ken-ichi; Kajiwara, Yosuke; Ishida, Masahiko; Nakamura, Yasunobu; Manako, Takashi; Saitoh, Eiji; Yorozu, Shinichi

    2012-06-17

    Energy harvesting technologies, which generate electricity from environmental energy, have been attracting great interest because of their potential to power ubiquitously deployed sensor networks and mobile electronics. Of these technologies, thermoelectric (TE) conversion is a particularly promising candidate, because it can directly generate electricity from the thermal energy that is available in various places. Here we show a novel TE concept based on the spin Seebeck effect, called 'spin-thermoelectric (STE) coating', which is characterized by a simple film structure, convenient scaling capability, and easy fabrication. The STE coating, with a 60-nm-thick bismuth-substituted yttrium iron garnet (Bi:YIG) film, is applied by means of a highly efficient process on a non-magnetic substrate. Notably, spin-current-driven TE conversion is successfully demonstrated under a temperature gradient perpendicular to such an ultrathin STE-coating layer (amounting to only 0.01% of the total sample thickness). We also show that the STE coating is applicable even on glass surfaces with amorphous structures. Such a versatile implementation of the TE function may pave the way for novel applications making full use of omnipresent heat.

  16. Computational dynamics of acoustically driven microsphere systems

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B.

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  17. FPGA Congestion-Driven Placement Refinement

    Energy Technology Data Exchange (ETDEWEB)

    Vicente de, J.

    2005-07-01

    The routing congestion usually limits the complete proficiency of the FPGA logic resources. A key question can be formulated regarding the benefits of estimating the congestion at placement stage. In the last years, it is gaining acceptance the idea of a detailed placement taking into account congestion. In this paper, we resort to the Thermodynamic Simulated Annealing (TSA) algorithm to perform a congestion-driven placement refinement on the top of the common Bounding-Box pre optimized solution. The adaptive properties of TSA allow the search to preserve the solution quality of the pre optimized solution while improving other fine-grain objectives. Regarding the cost function two approaches have been considered. In the first one Expected Occupation (EO), a detailed probabilistic model to account for channel congestion is evaluated. We show that in spite of the minute detail of EO, the inherent uncertainty of this probabilistic model impedes to relieve congestion beyond the sole application of the Bounding-Box cost function. In the second approach we resort to the fast Rectilinear Steiner Regions algorithm to perform not an estimation but a measurement of the global routing congestion. This second strategy allows us to successfully reduce the requested channel width for a set of benchmark circuits with respect to the widespread Versatile Place and Route (VPR) tool. (Author) 31 refs.

  18. Propeller-driven Outflows and Disk Oscillations

    CERN Document Server

    Romanova, M M; Koldoba, A V; Lovelace, R V E

    2005-01-01

    We report the discovery of propeller-driven outflows in axisymmetric magnetohydrodynamic simulations of disk accretion to rapidly rotating magnetized stars. Matter outflows in a wide cone and is centrifugally ejected from the inner regions of the disk. Closer to the axis there is a strong, collimated, magnetically dominated outflow of energy and angular momentum carried by the open magnetic field lines from the star. The ``efficiency'' of the propeller may be very high in the respect that most of the incoming disk matter is expelled from the system in winds. The star spins-down rapidly due to the magnetic interaction with the disk through closed field lines and with corona through open field lines. Diffusive and viscous interaction between magnetosphere and the disk are important: no outflows were observed for very small values of the diffusivity and viscosity. These simulation results are applicable to the early stages of evolution of classical T Tauri stars and to different stages of evolution of cataclysmi...

  19. Computational dynamics of acoustically driven microsphere systems.

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry. PMID:26871188

  20. IMPROVED COVARIANCE DRIVEN BLIND SUBSPACE IDENTIFICATION METHOD

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhiyi; FAN Jiangling; HUA Hongxing

    2006-01-01

    An improved covariance driven subspace identification method is presented to identify the weakly excited modes. In this method, the traditional Hankel matrix is replaced by a reformed one to enhance the identifiability of weak characteristics. The robustness of eigenparameter estimation to noise contamination is reinforced by the improved Hankel matrix. In combination with component energy index (CEI) which indicates the vibration intensity of signal components, an alternative stabilization diagram is adopted to effectively separate spurious and physical modes. Simulation of a vibration system of multiple-degree-of-freedom and experiment of a frame structure subject to wind excitation are presented to demonstrate the improvement of the proposed blind method. The performance of this blind method is assessed in terms of its capability in extracting the weak modes as well as the accuracy of estimated parameters. The results have shown that the proposed blind method gives a better estimation of the weak modes from response signals of small signal to noise ratio (SNR)and gives a reliable separation of spurious and physical estimates.

  1. 14 CFR 36.9 - Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes. 36.9 Section 36.9 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION General §...

  2. Hydrogel Actuation by Electric Field Driven Effects

    Science.gov (United States)

    Morales, Daniel Humphrey

    Hydrogels are networks of crosslinked, hydrophilic polymers capable of absorbing and releasing large amounts of water while maintaining their structural integrity. Polyelectrolyte hydrogels are a subset of hydrogels that contain ionizable moieties, which render the network sensitive to the pH and the ionic strength of the media and provide mobile counterions, which impart conductivity. These networks are part of a class of "smart" material systems that can sense and adjust their shape in response to the external environment. Hence, the ability to program and modulate hydrogel shape change has great potential for novel biomaterial and soft robotics applications. We utilized electric field driven effects to manipulate the interaction of ions within polyelectrolyte hydrogels in order to induce controlled deformation and patterning. Additionally, electric fields can be used to promote the interactions of separate gel networks, as modular components, and particle assemblies within gel networks to develop new types of soft composite systems. First, we present and analyze a walking gel actuator comprised of cationic and anionic gel legs attached by electric field-promoted polyion complexation. We characterize the electro-osmotic response of the hydrogels as a function of charge density and external salt concentration. The gel walkers achieve unidirectional motion on flat elastomer substrates and exemplify a simple way to move and manipulate soft matter devices in aqueous solutions. An 'ionoprinting' technique is presented with the capability to topographically structure and actuate hydrated gels in two and three dimensions by locally patterning ions induced by electric fields. The bound charges change the local mechanical properties of the gel to induce relief patterns and evoke localized stress, causing rapid folding in air. The ionically patterned hydrogels exhibit programmable temporal and spatial shape transitions which can be tuned by the duration and/or strength of

  3. Numerical Simulations of Boundary-Driven Dynamos

    Science.gov (United States)

    White, K.; Brummell, N.; Glatzmaier, G. A.

    2012-12-01

    An important topic of physics research is how magnetic fields are generated and maintained in the many astrophysical bodies where they are ubiquitously observed. Of particular interest, are reversals of magnetic fields of planets and stars, especially those of the Earth and the Sun. In an attempt to provide intuition on this problem, numerous physical dynamo experiments have been performed in different configurations. Recently, a tremendous breakthrough was made in the Von Karman sodium (VKS) experiments in France when the most realistic laboratory fluid dynamo to date was produced by driving an unconstrained flow in a cylinder of liquid sodium (Monchaux et al, 2007, PRL). One of the curiosities of the VKS experiment however is the effect of the composition of the impellers that drive the flow. Steel blades failed to produce a dynamo, but soft iron impellers, which have much higher magnetic permeability, succeeded. The role of the magnetic properties of the boundaries in boundary-driven dynamos is therefore clearly of interest. Kinematic and laminar numerical dynamo simulations (Giesecke et al, 2010, PRL & Gissinger et al, 2008 EPL) have shed some light but turbulent, nonlinear simulations are necessary. Roberts, Glatzmaier & Clune 2010 created a simplified model of the VKS setup by using three-dimensional numerical simulations in a spherical geometry with differential zonal motions of the boundary replacing the driving impellers of the VKS experiment. We have extended these numerical simulations further towards a more complete understanding of such boundary-forced dynamos. In particular, we have examined the effect of the magnetic boundary conditions - changes in the wall thickness, the magnetic permeability, and the electrical conductivity - on the mechanisms responsible for dynamo generation. Enhanced permeability, conductivity and wall thickness all help dynamo action to different degrees. We are further extending our investigations to asymmetric forcing to

  4. Stochastically driven instability in rotating shear flows

    International Nuclear Information System (INIS)

    The origin of hydrodynamic turbulence in rotating shear flows is investigated, with particular emphasis on the flows whose angular velocity decreases but whose specific angular momentum increases with the increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain the observed data. Such a mismatch between the linear theory and the observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and then the corresponding turbulence therein is ruled out. This work explores the effect of stochastic noise on such hydrodynamic flows. We essentially concentrate on a small section of such a flow, which is nothing but a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disc. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities and hence large energy dissipations of perturbation, which presumably generate the instability. A range of angular velocity (Ω) profiles of the background flow, starting from that of a constant specific angular momentum (λ = Ωr2; r being the radial coordinate) to a constant circular velocity (vϕ = Ωr), is explored. However, all the background angular velocities exhibit identical growth and roughness exponents of their perturbations, revealing a unique universality class for the stochastically forced hydrodynamics of rotating shear flows. This work, to the best of our knowledge, is the first attempt to understand the origin of instability and turbulence in three-dimensional Rayleigh stable rotating shear flows by introducing additive noise to the underlying linearized governing equations. This has important implications to resolve the turbulence problem in astrophysical hydrodynamic flows such as accretion discs. (paper)

  5. Shadow-driven 4D haptic visualization.

    Science.gov (United States)

    Zhang, Hui; Hanson, Andrew

    2007-01-01

    Just as we can work with two-dimensional floor plans to communicate 3D architectural design, we can exploit reduced-dimension shadows to manipulate the higher-dimensional objects generating the shadows. In particular, by taking advantage of physically reactive 3D shadow-space controllers, we can transform the task of interacting with 4D objects to a new level of physical reality. We begin with a teaching tool that uses 2D knot diagrams to manipulate the geometry of 3D mathematical knots via their projections; our unique 2D haptic interface allows the user to become familiar with sketching, editing, exploration, and manipulation of 3D knots rendered as projected imageson a 2D shadow space. By combining graphics and collision-sensing haptics, we can enhance the 2D shadow-driven editing protocol to successfully leverage 2D pen-and-paper or blackboard skills. Building on the reduced-dimension 2D editing tool for manipulating 3D shapes, we develop the natural analogy to produce a reduced-dimension 3D tool for manipulating 4D shapes. By physically modeling the correct properties of 4D surfaces, their bending forces, and their collisions in the 3D haptic controller interface, we can support full-featured physical exploration of 4D mathematical objects in a manner that is otherwise far beyond the experience accessible to human beings. As far as we are aware, this paper reports the first interactive system with force-feedback that provides "4D haptic visualization" permitting the user to model and interact with 4D cloth-like objects.

  6. The evolution of information-driven safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Budlong-sylvester, Kory W [Los Alamos National Laboratory; Pilat, Joseph F [Los Alamos National Laboratory

    2010-10-14

    From the adoption of the Model Additional Protocol and integrated safeguards in the 1990s, to current International Atomic Energy Agency (IAEA) efforts to deal with cases of noncompliance, the question of how the Agency can best utilize all the information available to it remains of great interest and increasing importance. How might the concept of 'information-driven' safeguards (IDS) evolve in the future? The ability of the Agency to identify and resolve anomalies has always been important and has emerged as a core Agency function in recent years as the IAEA has had to deal with noncompliance in Iran and the Democratic People's Republic of Korea (DPRK). Future IAEA safeguards implementation should be designed with the goal of facilitating and enhancing this vital capability. In addition, the Agency should utilize all the information it possesses, including its in-house assessments and expertise, to direct its safeguards activities. At the State level, knowledge of proliferation possibilities is currently being used to guide the analytical activities of the Agency and to develop inspection plans. How far can this approach be extended? Does it apply across State boundaries? Should it dictate a larger fraction of safeguards activities? Future developments in IDS should utilize the knowledge resident within the Agency to ensure that safeguards resources flow to where they are most needed in order to address anomalies first and foremost, but also to provide greater confidence in conclusions regarding the absence of undeclared nuclear activities. The elements of such a system and related implementation issues are assessed in this paper.

  7. Neutronic parameters characterizing accelerator driven system (ADS)

    International Nuclear Information System (INIS)

    An hybrid system is a reactor where an external source of spallation neutrons is supplied to a subcritical multiplying medium. The neutronic parameters characterising such a system include, in addition to the multiplication factor which measures the sub-criticality level, another physics parameter measuring the 'importance' of the external source. The aim of this thesis is, on the one hand, to investigate basic neutronic phenomena taking place in fast sub- critical media in either steady-state or transient operation, and, on the other hand, to assess the performance of the ERANOS neutronic code package applied to the analysis of such systems. To this aim, the first part of the work is focused on the MUSE program and in particular the MUSE3 experiment, which consists of different sub-critical configurations driven by a 14-MeV neutron source. This study has been pursued in two directions : the first one was the interpretation of the calculation-experiment (C-E) discrepancies which lead to the development of original calculation methods for sensitivity studies ; the second one was the experimental analysis which allowed an extensive neutronic characterization of the sub-critical system. A correlation between the external source importance and some directly measurable parameters (i.e. fission rate) was derived. The second part of the thesis addresses representativity issues between an experimental facility and an actual power reactor. Important conclusions have been drawn with regard to the operation of an ADS. Finally, representativity studies lead to the recommendation that a demonstration reactor should be built before an industrial plant is constructed. (author)

  8. OSCILLATION-DRIVEN MAGNETOSPHERIC ACTIVITY IN PULSARS

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Meng-Xiang; Xu, Ren-Xin; Zhang, Bing, E-mail: linmx97@gmail.com, E-mail: r.x.xu@pku.edu.cn, E-mail: zhang@physics.unlv.edu [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)

    2015-02-01

    We study the magnetospheric activity in the polar cap region of pulsars under stellar oscillations. The toroidal oscillation of the star propagates into the magnetosphere, which provides additional voltage due to unipolar induction, changes Goldreich-Julian charge density from the traditional value due to rotation, and hence influences particle acceleration. We present a general solution of the effect of oscillations within the framework of the inner vacuum gap model and consider three different inner gap modes controlled by curvature radiation, inverse Compton scattering, and two-photon annihilation, respectively. With different pulsar parameters and oscillation amplitudes, one of three modes would play a dominant role in defining the gap properties. When the amplitude of oscillation exceeds a critical value, mode changing occurs. Oscillations also lead to a change of the size of the polar cap. As applications, we show the inner gap properties under oscillations in both normal pulsars and anomalous X-ray pulsars/soft gamma-ray repeaters (AXPs/SGRs). We interpret the onset of radio emission after glitches/flares in AXPs/SGRs as due to oscillation-driven magnetic activities in these objects, within the framework of both the magnetar model and the solid quark star model. Within the magnetar model, radio activation may be caused by the enlargement of the effective polar cap angle and the radio emission beam due to oscillation, whereas within the solid quark star angle, it may be caused by activation of the pulsar inner gap from below the radio emission death line due to an oscillation-induced voltage enhancement. The model can also explain the glitch-induced radio profile change observed in PSR J1119–6127.

  9. Chemical reactions driven by concentrated solar energy

    Science.gov (United States)

    Levy, Moshe

    Solar energy can be used for driving endothermic reactions, either photochemically or thermally. The fraction of the solar spectrum that can be photochemically active is quite small. Therefore, it is desirable to be able to combine photochemical and thermal processes in order to increase the overall efficiency. Two thermally driven reactions are being studied: oil shale gasification and methane reforming. In both cases, the major part of the work was done in opaque metal reactors where photochemical reactions cannot take place. We then proceeded working in transparent quartz reactors. The results are preliminary, but they seem to indicate that there may be some photochemical enhancement. The experimental solar facilities used for this work include the 30 kW Schaeffer Solar Furnace and the 3 MW Solar Central Receiver in operation at the Weizmann Institute. The furnace consists of a 96 sq. m flat heliostat, that follows the sun by computer control. It reflects the solar radiation onto a spherical concentrator, 7.3 m in diameter, with a rim angle of 65 degrees. The furnace was characterized by radiometric and calorimetric measurements to show a solar concentration ratio of over 10,000 suns. The central receiver consists of 64 concave heliostats, 54 sq. m each, arranged in a north field and facing a 52 m high tower. The tower has five target levels that can be used simultaneously. The experiments with the shale gasification were carried out at the lowest level, 20 m above ground, which has the lowest solar efficiency and is assigned for low power experiments. We used secondary concentrators to boost the solar flux.

  10. En route to matter-antimatter pair plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Stenson, Eve V.; Hergenhahn, Uwe; Paschkowski, Norbert; Saitoh, Haruhiko; Stanja, Juliane [Max Planck Institute for Plasma Physics, Greifswald and Garching (Germany); Niemann, Holger; Sunn Pedersen, Thomas [Max Planck Institute for Plasma Physics, Greifswald and Garching (Germany); Ernst Moritz Arndt University of Greifswald, Greifswald (Germany); Schweikhard, Lutz [Ernst Moritz Arndt University of Greifswald, Greifswald (Germany); Hugenschmidt, Christoph [Technische Universitaet Muenchen, Garching (Germany); Danielson, James R.; Surko, Clifford M. [University of California, San Diego, La Jolla (United States)

    2015-05-01

    The APEX and PAX projects have as their overarching goal the laboratory creation and confinement of the world's first positron-electron pair plasma. Plasmas of this type have been the subject of hundreds of theoretical investigations and are also believed to play a role in various astrophysical environments. In order to achieve this goal in an experimentally accessible volume (e.g., 10 liters), a record number (≥ 10{sup 10}) of cold (∝ 1 eV) positrons are to be accumulated and combined with a corresponding population of electrons. Notable requirements include a high-intensity positron beam (such as NEPOMUC), a suitable magnetic confinement device for the pair plasma (such as a levitated dipole), high-efficiency tools for bridging the two (i.e., means by which the positrons can be efficiently cooled, trapped, and injected across flux surfaces), and diagnostics not only for the pair plasma, but also for the positron beam and for intermediary non-neutral plasmas. This talk will summarize the project as a whole and recent work by the APEX/PAX team on its various elements.

  11. Antiproton cell experiment: antimatter is a better killer

    CERN Multimedia

    2006-01-01

    "European Organization for Nuclear Research is reporting that results from a three year study of antiprotons for neoplasm irrdiation showed a better cellular killer with a smaller lethal dose." (1,5 page)

  12. Baryon symmetric big-bang cosmology. [matter-antimatter symmetry

    Science.gov (United States)

    Stecker, F. W.

    1978-01-01

    The framework of baryon-symmetric big-bang cosmology offers the greatest potential for deducing the evolution of the universe as a consequence of physical laws and processes with the minimum number of arbitrary assumptions as to initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the universe and how galaxies and galaxy clusters are formed, and also provides the only acceptable explanation at present for the origin of the cosmic gamma ray background radiation.

  13. High nuclear temperatures by antimatter-matter annihilation

    International Nuclear Information System (INIS)

    It is suggested that the quark-gluon phase be created through the use of antiproton or antideuteron beams. The first advantage to this method, using higher energy antiprotons than 1.5 GeV/c, is that the higher momenta antiprotons penetrate more deeply so that mesons produced are more nearly contained within the nucleus. Another advantage is that the annihilation products are very forward-peaked and tend to form a beam of mesons so that the energy density does not disperse very rapidly. Calculations were performed using the intranuclear cascade to try to follow the process of annihilation in some detail. The intranuclear cascade type calculation method is compared to the hydrodynamic approach. 8 refs., 8 figs

  14. High nuclear temperatures by antimatter-matter annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, W.R.; Strottman, D.

    1985-01-01

    It is suggested that the quark-gluon phase be created through the use of antiproton or antideuteron beams. The first advantage to this method, using higher energy antiprotons than 1.5 GeV/c, is that the higher momenta antiprotons penetrate more deeply so that mesons produced are more nearly contained within the nucleus. Another advantage is that the annihilation products are very forward-peaked and tend to form a beam of mesons so that the energy density does not disperse very rapidly. Calculations were performed using the intranuclear cascade to try to follow the process of annihilation in some detail. The intranuclear cascade type calculation method is compared to the hydrodynamic approach. 8 refs., 8 figs. (LEW)

  15. Polarizing matter and antimatter: A new method. Final report

    International Nuclear Information System (INIS)

    Several years ago a self-polarization effect for stored (anti-)protons and ions was investigated theoretically. The effect is based on the well-known Stern-Gerlach effect in gradient fields. The aim of the ongoing measurements at the Indiana University Cyclotron Facility (IUCF) is to verify experimentally the various assumptions on which this effect is based. The final goal is to demonstrate this new polarization effect. The proposed effect could be a powerful tool to produce polarized stored hadron beams both in the low-energy range and at SSC and LHC energies. In this progress report the authors will describe the progress in three parts: (A) experimental work at IUCF Cooler Ring; (B) the extensive computer simulations of the spin stability for the IUCF Cooler Ring; and (C) theoretical studies

  16. Strategy-driven talent management a leadership imperative

    CERN Document Server

    Silzer, Rob

    2009-01-01

    A Publication of the Society for Industrial and Organizational Psychology Praise for Strategy-Driven Talent Management ""Silzer and Dowell''s Strategy-Driven Talent Management provides a comprehensive overview of the different elements of the best talent management processes used in organizations today. This is a valuable resource for leaders and managers, HR practitioners and anyone involved in developing leadership talent.""-Ed Lawler, Professor, School of Business, University of Southern California ""Talent is the key to successful execution of a winning business strategy. Strategy-Driven T

  17. 2nd International Conference on Cable-Driven Parallel Robots

    CERN Document Server

    Bruckmann, Tobias

    2015-01-01

    This volume presents the outcome of the second forum to cable-driven parallel robots, bringing the cable robot community together. It shows the new ideas of the active researchers developing cable-driven robots. The book presents the state of the art, including both summarizing contributions as well as latest research and future options. The book cover all topics which are essential for cable-driven robots: Classification Kinematics, Workspace and Singularity Analysis Statics and Dynamics Cable Modeling Control and Calibration Design Methodology Hardware Development Experimental Evaluation Prototypes, Application Reports and new Application concepts

  18. Universal triangular spectra in parametrically-driven systems

    Energy Technology Data Exchange (ETDEWEB)

    Akhmediev, Nail [Optical Sciences Group, Research School of Physics and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200 (Australia); Ankiewicz, Adrian, E-mail: ana124@rsphysse.anu.edu.a [Optical Sciences Group, Research School of Physics and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200 (Australia); Soto-Crespo, J.M. [Instituto de Optica, C.S.I.C., Serrano 121, 28006 Madrid (Spain); Dudley, John M. [Institut FEMTO-ST, UMR 6174 CNRS-Universite de Franche-Comte, 25030 Besancon (France)

    2011-01-17

    We analyse triangular spectra that appear in many branches of physics that deal with parametrically-driven systems, and give a simple theoretical analysis for them in terms of the nonlinear dynamics of multimode fields. Such spectra appear universally as a result of an exponential decay of the nonlinearly generated frequency modes of many parametrically-driven systems, and have been confirmed by recent observations of noise-driven supercontinuum generation in optical fibers. We demonstrate that such universal triangular spectra (UTS) can be well-described by the analytical expressions for the spectra of Akhmediev breather (AB) solutions at the point of maximal compression.

  19. Into the Surge of Network-driven Innovation

    DEFF Research Database (Denmark)

    Østergaard, Claus Møller; Rosenstand, Claus Andreas Foss; Gertsen, Frank;

    2013-01-01

    The ambition of this paper is to provide a better theoretical understanding of innovation by framing it in a long historical, economical, and societal perspective. The research question of the paper is: What characterize the historical surges of innovation? Based on previous works and research...... this is examined from the 1880’s up until today. The contribution of the paper is a societal perspective on innovation, where the difference between industrial society and knowledge society leads into the surge of network-driven innovation. Network-driven innovation is unfolded on top of the known cost- driven...

  20. Capacitive Sensor With Driven Shields And Bridge Circuit

    Science.gov (United States)

    Vranish, John M.

    1994-01-01

    Like other capaciflectors described in prior articles in NASA Tech Briefs, this one includes sensing electrode driven by alternating voltage, giving rise to electric field in vicinity of electrode; object entering electric field detected by its effect on capacitance between sensing electrode and electrical ground. Also includes shielding electrode (in this case, driven shield 1), excited via voltage follower at same voltage as that applied to sensing electrode to concentrate more of electric field outward from sensing electrode, increasing sensitivity and range of sensor. Because shielding electrode driven via voltage follower, it does not present significant electrical load to source of alternating voltage.

  1. Directed transport and localization in phase-modulated driven lattices

    CERN Document Server

    Petri, Christoph; Diakonos, Fotis K; Schmelcher, Peter

    2010-01-01

    We explore the dynamics of non-interacting particles loaded into a phase-modulated one-dimensional lattice formed by laterally oscillating square barriers. Tuning the parameters of the driven unit cell of the lattice selected parts of the classical phase space can be manipulated in a controllable manner. We find superdiffusion in position space for all parameters regimes. A directed current of an ensemble of particles can be created through locally breaking the spatiotemporal symmetries of the time-driven potential. Magnitude and direction of the current are tunable. Several mechanisms for transient localization and trapping of particles in different wells of the driven unit cell are presented and analyzed.

  2. Research on method of pressure grouting piling of driven tube

    Institute of Scientific and Technical Information of China (English)

    Dianqi PAN; Zupei ZHANG; Diancai PAN; Yong CHEN; Maosen TAN

    2006-01-01

    The pressure grouting pile of driven tube can improve the load bearing capacity of the single pile from the mechanism of pressure grouting pile of driven tube. On the basis of analyzing the mechanism, the authors designed the machines and tools of pressure grouting, determined the operating manufacture and technology parameter on the pressure grouting secondly. The result shows that the pressure grouting pile of driven tube not only changes the pile type but also reduce the length of the pile and its engineering cost, it enhances the load bearing capacity of single pile an the same time.

  3. Proliferation Potential of Accelerator-Driven Systems: Feasibility Calculations

    International Nuclear Information System (INIS)

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium

  4. Combining environment-driven adaptation and task-driven optimisation in evolutionary robotics.

    Science.gov (United States)

    Haasdijk, Evert; Bredeche, Nicolas; Eiben, A E

    2014-01-01

    Embodied evolutionary robotics is a sub-field of evolutionary robotics that employs evolutionary algorithms on the robotic hardware itself, during the operational period, i.e., in an on-line fashion. This enables robotic systems that continuously adapt, and are therefore capable of (re-)adjusting themselves to previously unknown or dynamically changing conditions autonomously, without human oversight. This paper addresses one of the major challenges that such systems face, viz. that the robots must satisfy two sets of requirements. Firstly, they must continue to operate reliably in their environment (viability), and secondly they must competently perform user-specified tasks (usefulness). The solution we propose exploits the fact that evolutionary methods have two basic selection mechanisms-survivor selection and parent selection. This allows evolution to tackle the two sets of requirements separately: survivor selection is driven by the environment and parent selection is based on task-performance. This idea is elaborated in the Multi-Objective aNd open-Ended Evolution (monee) framework, which we experimentally validate. Experiments with robotic swarms of 100 simulated e-pucks show that monee does indeed promote task-driven behaviour without compromising environmental adaptation. We also investigate an extension of the parent selection process with a 'market mechanism' that can ensure equitable distribution of effort over multiple tasks, a particularly pressing issue if the environment promotes specialisation in single tasks. PMID:24901702

  5. Flow-driven waves and sink-driven oscillations during aggregation of Dictyostelium discoideum

    Science.gov (United States)

    Gholami, Azam; Zykov, Vladimir; Steinbock, Oliver; Bodenschatz, Eberhard

    The slime mold Dictyostelium discoideum (D.d) is a well-known model system for the study of biological pattern formation. Under starvation, D.d. cells aggregate chemotactically towards cAMP signals emitted periodically from an aggregation center. In the natural environment, D.d cells may experience fluid flows that can profoundly change the underlying wave generation process. We investigate spatial-temporal dynamics of a uniformly distributed population of D.d. cells in a flow-through narrow microfluidic channel with a cell-free inlet area. We show that flow can significantly influence the dynamics of the system and lead to a flow- driven instability that initiate downstream traveling cAMP waves. We also show that cell-free boundary regions have a significant effect on the observed patterns and can lead to a new kind of instability. Since there are no cells in the inlet to produce cAMP, the points in the vicinity of the inlet lose cAMP due to advection or diffusion and gain only a little from the upstream of the channel (inlet). In other words, there is a large negative flux of cAMP in the neighborhood close to the inlet, which can be considered as a sink. This negative flux close to the inlet drives a new kind of instability called sink-driven oscillations. Financial support of the MaxSynBio Consortium is acknowledged.

  6. Combining Environment-Driven Adaptation and Task-Driven Optimisation in Evolutionary Robotics

    Science.gov (United States)

    Haasdijk, Evert; Bredeche, Nicolas; Eiben, A. E.

    2014-01-01

    Embodied evolutionary robotics is a sub-field of evolutionary robotics that employs evolutionary algorithms on the robotic hardware itself, during the operational period, i.e., in an on-line fashion. This enables robotic systems that continuously adapt, and are therefore capable of (re-)adjusting themselves to previously unknown or dynamically changing conditions autonomously, without human oversight. This paper addresses one of the major challenges that such systems face, viz. that the robots must satisfy two sets of requirements. Firstly, they must continue to operate reliably in their environment (viability), and secondly they must competently perform user-specified tasks (usefulness). The solution we propose exploits the fact that evolutionary methods have two basic selection mechanisms–survivor selection and parent selection. This allows evolution to tackle the two sets of requirements separately: survivor selection is driven by the environment and parent selection is based on task-performance. This idea is elaborated in the Multi-Objective aNd open-Ended Evolution (monee) framework, which we experimentally validate. Experiments with robotic swarms of 100 simulated e-pucks show that monee does indeed promote task-driven behaviour without compromising environmental adaptation. We also investigate an extension of the parent selection process with a ‘market mechanism’ that can ensure equitable distribution of effort over multiple tasks, a particularly pressing issue if the environment promotes specialisation in single tasks. PMID:24901702

  7. Combining environment-driven adaptation and task-driven optimisation in evolutionary robotics.

    Science.gov (United States)

    Haasdijk, Evert; Bredeche, Nicolas; Eiben, A E

    2014-01-01

    Embodied evolutionary robotics is a sub-field of evolutionary robotics that employs evolutionary algorithms on the robotic hardware itself, during the operational period, i.e., in an on-line fashion. This enables robotic systems that continuously adapt, and are therefore capable of (re-)adjusting themselves to previously unknown or dynamically changing conditions autonomously, without human oversight. This paper addresses one of the major challenges that such systems face, viz. that the robots must satisfy two sets of requirements. Firstly, they must continue to operate reliably in their environment (viability), and secondly they must competently perform user-specified tasks (usefulness). The solution we propose exploits the fact that evolutionary methods have two basic selection mechanisms-survivor selection and parent selection. This allows evolution to tackle the two sets of requirements separately: survivor selection is driven by the environment and parent selection is based on task-performance. This idea is elaborated in the Multi-Objective aNd open-Ended Evolution (monee) framework, which we experimentally validate. Experiments with robotic swarms of 100 simulated e-pucks show that monee does indeed promote task-driven behaviour without compromising environmental adaptation. We also investigate an extension of the parent selection process with a 'market mechanism' that can ensure equitable distribution of effort over multiple tasks, a particularly pressing issue if the environment promotes specialisation in single tasks.

  8. Coalescence cascade of dissipative solitons in parametrically driven systems.

    Science.gov (United States)

    Clerc, M G; Coulibaly, S; Gordillo, L; Mujica, N; Navarro, R

    2011-09-01

    Parametrically driven spatially extended systems exhibit uniform oscillations which are modulationally unstable. The resulting periodic state evolves to the creation of a gas of dissipative solitons. Driven by the interaction of dissipative solitons, the multisoliton state undergoes a cascade of coalescence processes, where the average soliton separation distance obeys a temporal self-similar law. Starting from the soliton pair interaction law, we have derived analytically and characterized the law of this multisoliton coarsening process. A comparison of numerical results obtained with different models such as the parametrically driven damped nonlinear Schrödinger equation, a vertically driven chain of pendula, and a parametrically forced magnetic wire, shows remarkable agreement. Both phenomena, the pair interaction law and the coarsening process, are also observed experimentally in a quasi-one-dimensional layer of Newtonian fluid which is oscillated vertically. PMID:22060473

  9. Vapor Compressor Driven Hybrid Two-Phase Loop Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will demonstrate a vapor compressor driven hybrid two-phase loop technology. The hybrid two-phase loop...

  10. Reflected Backward Stochastic Differential Equations Driven by Countable Brownian Motions

    Directory of Open Access Journals (Sweden)

    Pengju Duan

    2013-01-01

    Full Text Available This paper deals with a new class of reflected backward stochastic differential equations driven by countable Brownian motions. The existence and uniqueness of the RBSDEs are obtained via Snell envelope and fixed point theorem.

  11. Internet-based event synchronization communication driven telerobotics

    Institute of Scientific and Technical Information of China (English)

    Xie Xiaohui; Sun Lining; Du Zhijiang; Cai Hegao

    2005-01-01

    Based on QoS (quality of service) parameters: time delay, jitter, bandwidth and package loss. As time delay in the Internet is variable, it is hard to compensate it by traditional methods. Event synchronization communication driven method is proposed to overcome the negative effects induced by time delay. This method is a non-time based method and it can get rid of the effects of time in the control loop of telerobotics. Stability, transparency and synchronization can be maintained in it by event-driven method. Multimodal enhanced telerobotics is put forward with its feedback including force, video, audio and temperature etc. The use of multimodal feedback improves the efficiency and safety of the whole system. Synchronization in multimodal feedback is hard to ensure and event-driven method is also good for it. Experiments on an Internet-based shaft-hole assemblage system show good results by using event synchronization communication driven method and UDP protocol.

  12. Theoretical and experimental analysis of an optical driven servo system

    Science.gov (United States)

    Lu, F.; Wang, X. J.; Huang, J. H.; Liu, Y. F.

    2016-09-01

    An optical driven servo system model based on single-type PLZT ceramic is proposed in this paper. The control equation of the proposed servo system is derived based on the mathematical model of PLZT with coupled multi-physics fields. The parameters of photodeformation of the PLZT actuator during both the illumination phase and light off phase are identified through the static experiment. Then displacement response of optical driven servo system is numerically simulated based on the control equation presented in this paper. After that, the closed-loop control experiment of optical driven servo system based on PLZT single-type ceramic with a simple on-off method is carried out. The experimental results show that the optical driven servo system with simple on-off method can achieve the target displacement by applying UV light to the PLZT actuator. Furthermore, an improved on-off control strategy is proposed to decrease the undesirable fluctuation around the target displacement.

  13. Passive and Driven Trends in the Evolution of Complexity

    CERN Document Server

    Yaeger, Larry; Sporns, Olaf

    2011-01-01

    The nature and source of evolutionary trends in complexity is difficult to assess from the fossil record, and the driven vs. passive nature of such trends has been debated for decades. There are also questions about how effectively artificial life software can evolve increasing levels of complexity. We extend our previous work demonstrating an evolutionary increase in an information theoretic measure of neural complexity in an artificial life system (Polyworld), and introduce a new technique for distinguishing driven from passive trends in complexity. Our experiments show that evolution can and does select for complexity increases in a driven fashion, in some circumstances, but under other conditions it can also select for complexity stability. It is suggested that the evolution of complexity is entirely driven---just not in a single direction---at the scale of species. This leaves open the question of evolutionary trends at larger scales.

  14. Static large deviations of boundary driven exclusion processes

    CERN Document Server

    Farfan, Jonathan

    2009-01-01

    We prove that the stationary measure associated to a boundary driven exclusion process in any dimension satisfies a large deviation principle with rate function given by the quasi potential of the Freidlin and Wentzell theory.

  15. Interactive Mouse-Driven Animation of Mathematical Processes.

    Science.gov (United States)

    Greenleaf, Newcomb

    1986-01-01

    Provides examples from elementary mathematics principles which illustrate some of the advantages of an interactive mouse-driven animation. Explains the effectiveness of this approach with exercises dealing with a plane of waves and quadratic formulas. (ML)

  16. Quantum-mechanical aspects of classically chaotic driven systems

    International Nuclear Information System (INIS)

    This paper treats atoms and molecules in laser fields as periodically driven quantum systems. The paper concludes by determining that stochastic excitation is possible in quantum systems with quasiperiodic driving. 17 refs

  17. What and how about customer-driven product development

    DEFF Research Database (Denmark)

    Sommer, Anita Friis; Steger-Jensen, Kenn

    2012-01-01

    Collaborative product development is of increasing interest as customer demands increases while product life cycles decrease. This study investigates how suppliers handle active customers including managing customer requests for new products and customer-driven product development. A large...

  18. Event-Driven Process Chains (EPC)

    Science.gov (United States)

    Mendling, Jan

    This chapter provides a comprehensive overview of Event-driven Process Chains (EPCs) and introduces a novel definition of EPC semantics. EPCs became popular in the 1990s as a conceptual business process modeling language in the context of reference modeling. Reference modeling refers to the documentation of generic business operations in a model such as service processes in the telecommunications sector, for example. It is claimed that reference models can be reused and adapted as best-practice recommendations in individual companies (see [230, 168, 229, 131, 400, 401, 446, 127, 362, 126]). The roots of reference modeling can be traced back to the Kölner Integrationsmodell (KIM) [146, 147] that was developed in the 1960s and 1970s. In the 1990s, the Institute of Information Systems (IWi) in Saarbrücken worked on a project with SAP to define a suitable business process modeling language to document the processes of the SAP R/3 enterprise resource planning system. There were two results from this joint effort: the definition of EPCs [210] and the documentation of the SAP system in the SAP Reference Model (see [92, 211]). The extensive database of this reference model contains almost 10,000 sub-models: 604 of them non-trivial EPC business process models. The SAP Reference model had a huge impact with several researchers referring to it in their publications (see [473, 235, 127, 362, 281, 427, 415]) as well as motivating the creation of EPC reference models in further domains including computer integrated manufacturing [377, 379], logistics [229] or retail [52]. The wide-spread application of EPCs in business process modeling theory and practice is supported by their coverage in seminal text books for business process management and information systems in general (see [378, 380, 49, 384, 167, 240]). EPCs are frequently used in practice due to a high user acceptance [376] and extensive tool support. Some examples of tools that support EPCs are ARIS Toolset by IDS

  19. Supernovae and AGN Driven Galactic Outflows

    Science.gov (United States)

    Sharma, Mahavir; Nath, Biman B.

    2013-01-01

    We present analytical solutions for winds from galaxies with a Navarro-Frank-White (NFW) dark matter halo. We consider winds driven by energy and mass injection from multiple supernovae (SNe), as well as momentum injection due to radiation from a central black hole. We find that the wind dynamics depends on three velocity scales: (1) v_\\star ˜ (\\dot{E} / 2 \\dot{M})^{1/2} describes the effect of starburst activity, with \\dot{E} and \\dot{M} as energy and mass injection rate in a central region of radius R; (2) v • ~ (GM •/2R)1/2 for the effect of a central black hole of mass M • on gas at distance R; and (3) v_{s} =(GM_h / 2 {C}r_s)^{1/2}, which is closely related to the circular speed (vc ) for an NFW halo, where rs is the halo scale radius and {C} is a function of the halo concentration parameter. Our generalized formalism, in which we treat both energy and momentum injection from starbursts and radiation from the central active galactic nucleus (AGN), allows us to estimate the wind terminal speed to be (4v 2 sstarf + 6(Γ - 1)v • 2 - 4v 2 s )1/2, where Γ is the ratio of force due to radiation pressure to gravity of the central black hole. Our dynamical model also predicts the following: (1) winds from quiescent star-forming galaxies cannot escape from 1011.5 M ⊙ ~ 1000 km s-1. We also find that the ratio [2v 2 sstarf - (1 - Γ)v • 2]/v 2 c dictates the amount of gas lost through winds. Used in conjunction with an appropriate relation between M • and Mh and an appropriate opacity of dust grains in infrared (K band), this ratio has the attractive property of being minimum at a certain halo mass scale (Mh ~ 1012-1012.5 M ⊙) that signifies the crossover of AGN domination in outflow properties from starburst activity at lower masses. We find that stellar mass for massive galaxies scales as M sstarfvpropM 0.26 h , and for low-mass galaxies, M sstarfvpropM 5/3 h .

  20. NEW PUNCHING MACHINE DRIVEN BY LINEAR INDUCTION MOTOR

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The research and application of the punching machine driven by a linear induction motor(LIM)are introducedThe fundamental principle,construction,performance and application are describedComparing this new model machine with its traditional form,the LIM driven punching machine has many great advantages,such as,simple construction,small size and mass,low production cost,short production time,easy to control,low noise and considerable energy saving

  1. Model driven product line engineering : core asset and process implications

    OpenAIRE

    Azanza Sesé, Maider

    2012-01-01

    Reuse is at the heart of major improvements in productivity and quality in Software Engineering. Both Model Driven Engineering (MDE) and Software Product Line Engineering (SPLE) are software development paradigms that promote reuse. Specifically, they promote systematic reuse and a departure from craftsmanship towards an industrialization of the software development process. MDE and SPLE have established their benefits separately. Their combination, here called Model Driven Product Line Engin...

  2. Model-driven software development approaches in robotics research

    OpenAIRE

    Ramaswamy, Arun Kumar; Monsuez, Bruno; Tapus, Adriana

    2014-01-01

    Recently, there is an encouraging trend in adopting model-driven engineering approaches for software development in robotics research. In this paper, currently available model-driven techniques in robotics are analyzed with respect to the domain-specific requirements. A conceptual overview of our software development approach called 'Self Adaptive Framework for Robotic Systems (SafeRobots)' is explained and we also try to position our approach within this model ecosystem.

  3. Criterion for phase separation in one-dimensional driven systems

    OpenAIRE

    Kafri, Y.; Levine, E.; Mukamel, D.; Schütz, G. M.; Török, J

    2002-01-01

    A general criterion for the existence of phase separation in driven density-conserving one-dimensional systems is proposed. It is suggested that phase separation is related to the size dependence of the steady-state currents of domains in the system. A quantitative criterion for the existence of phase separation is conjectured using a correspondence made between driven diffusive models and zero-range processes. The criterion is verified in all cases where analytical results are available, and...

  4. Toward a Theory of Purpose-Driven Urban Entrepreneurship

    OpenAIRE

    Cohen, B; Munoz, PA

    2015-01-01

    Inspired by Shrivastava and Kennelly, we aim to extend theory on place-based entrepreneurship by highlighting the uniqueness of cities and the interplay between purpose-driven entrepreneurs and the urban places where they operate. This article sets out to conceptualize a middle-range theoretical framework and establish the boundary conditions for purpose-driven urban entrepreneurship based on a combination of inductive reasoning and deductive theorizing. We draw from sustainability and territ...

  5. Nucleosynthesis of molybdenum in neutrino-driven winds

    CERN Document Server

    Bliss, Julia

    2015-01-01

    Neutrino-driven winds that follow core-collapse supernovae are an exciting astrophysical site for the production of heavy elements. Although hydrodynamical simulations show that the conditions in the wind are not extreme enough for a r-process up to uranium, neutrino-driven winds may be the astrophysical site where lighter heavy elements between Sr an Ag are produced, either by the weak r-process or by the $\

  6. Breaking of forward-backward symmetry in driven systems

    DEFF Research Database (Denmark)

    Szolnoki, Attila; Szabó, György

    1993-01-01

    The dynamical pair approximation was modified to study the stationary states in a two-dimensional repulsive-lattice-gas model driven far from equilibrium by the application of an external field. This approximation distinguishes between the forward, backward, and transverse directions with respect...... to the electric field. In the present driven system, the forward-backward symmetry is broken at the level of the pair approximation. The difference between the forward and backward directions is confirmed by Monte Carlo simulations....

  7. Transient buoyancy-driven ventilation: Part 2. Modelling heat transfer

    OpenAIRE

    Steven D. Sandbach and Gregory F. Lane-Serff

    2011-01-01

    A new mathematical model for buoyancy-driven ventilation [Sandbach SD, Lane-Serif GF. Transient buoyancy-driven ventilation: Part 1. Modelling advection. Building and Environment, 2011] is modified to include heat transfer at the boundaries. Heat transfers at the ceiling and floor are included, using Newton's law of cooling to model convective heat transfer between the air and the solid boundaries, Fourier's law to model conductive heat transfer through the floor and ceiling, and a linear ver...

  8. User-driven innovation in Supply and Value Networks

    DEFF Research Database (Denmark)

    Lassen, Astrid Heidemann; Jacobsen, Alexia; Wandahl, Søren;

    2011-01-01

    In order to address the lack of knowledge about readiness for implementing user-driven innovation at a network level, this paper develops a conceptual framework for assessment, and tests this in the context of the building material industry in Denmark. The results illustrate significant differences...... in user-driven innovation readiness between the network partners, and provide valuable knowledge on which areas to target in order to create a balanced network approach to the joint innovation activities....

  9. High Performance Visualization using Query-Driven Visualizationand Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Bethel, E. Wes; Campbell, Scott; Dart, Eli; Shalf, John; Stockinger, Kurt; Wu, Kesheng

    2006-06-15

    Query-driven visualization and analytics is a unique approach for high-performance visualization that offers new capabilities for knowledge discovery and hypothesis testing. The new capabilities akin to finding needles in haystacks are the result of combining technologies from the fields of scientific visualization and scientific data management. This approach is crucial for rapid data analysis and visualization in the petascale regime. This article describes how query-driven visualization is applied to a hero-sized network traffic analysis problem.

  10. Executive Compensation And Contract-Driven Earnings Management

    OpenAIRE

    Lan Sun

    2012-01-01

    Earnings management is found to be driven by different managerial incentives. Previous studies have identified that executive compensation contracts create incentives for earnings management. The agency theory and the positive accounting theory provide explanations for contract-driven earnings management. This study links the agency theory and the positive accounting theory and reviews the early executive compensation studies, bonus plan maximisation hypothesis and equity-based compensation. ...

  11. Behaviour of jacked and driven piles in sandy soil

    OpenAIRE

    Yang, J; Tham, LG; Lee, PKK; Chan, ST; Yu, F.

    2006-01-01

    As an alternative to conventional dynamic pile installation methods, pile jacking is an environmentally friendly technique that could become more widely accepted. Great concern has arisen over the performance of jacked piles as compared with that of driven piles. This paper describes a comprehensive field study that was aimed at investigating the differences and similarities between the behaviour of jacked H-piles and that of driven H-piles. The instrumented piles, varying in length from 32 t...

  12. User-driven innovation of an outpatient department

    DEFF Research Database (Denmark)

    Broberg, Ole; Edwards, Kasper

    2012-01-01

    This paper presents experiences from a user-driven innovation process of an outpatient department in a hospital. The mixing of methods from user-driven innovation and participatory design contributed to develop an innovative concept of the spatial and organizational design of an outpatient depart...... department in a hospital. Design games and tabletop simulation seem to be powerful tools in facilitating such a participatory process....

  13. Stress-Driven Selection of Novel Phenotypes

    Science.gov (United States)

    Fox, George E.; Stepaov, Victor G.; Liu, Yamei

    2011-01-01

    A process has been developed that can confer novel properties, such as metal resistance, to a host bacterium. This same process can also be used to produce RNAs and peptides that have novel properties, such as the ability to bind particular compounds. It is inherent in the method that the peptide or RNA will behave as expected in the target organism. Plasmid-born mini-gene libraries coding for either a population of combinatorial peptides or stable, artificial RNAs carrying random inserts are produced. These libraries, which have no bias towards any biological function, are used to transform the organism of interest and to serve as an initial source of genetic variation for stress-driven evolution. The transformed bacteria are propagated under selective pressure in order to obtain variants with the desired properties. The process is highly distinct from in vitro methods because the variants are selected in the context of the cell while it is experiencing stress. Hence, the selected peptide or RNA will, by definition, work as expected in the target cell as the cell adapts to its presence during the selection process. Once the novel gene, which produces the sought phenotype, is obtained, it can be transferred to the main genome to increase the genetic stability in the organism. Alternatively, the cell line can be used to produce novel RNAs or peptides with selectable properties in large quantity for separate purposes. The system allows for easy, large-scale purification of the RNAs or peptide products. The process has been reduced to practice by imposing sub-inhibitory concentrations of NiCl2 on cells of the bacterium Escherichia coli that were transformed separately with the peptide library and RNA library. The evolved resistant clones were isolated, and sequences of the selected mini-gene variants were established. Clones resistant to NiCl2 were found to carry identical plasmid variants with a functional mini-gene that specifically conferred significant nickel

  14. Dynamical Coulomb blockade of tunnel junctions driven by alternating voltages

    Science.gov (United States)

    Grabert, Hermann

    2015-12-01

    The theory of the dynamical Coulomb blockade is extended to tunneling elements driven by a time-dependent voltage. It is shown that, for standard setups where an external voltage is applied to a tunnel junction via an impedance, time-dependent driving entails an excitation of the modes of the electromagnetic environment by the applied voltage. Previous approaches for ac driven circuits need to be extended to account for the driven bath modes. A unitary transformation involving also the variables of the electromagnetic environment is introduced which allows us to split off the time dependence from the Hamiltonian in the absence of tunneling. This greatly simplifies perturbation-theoretical calculations based on treating the tunneling Hamiltonian as a perturbation. In particular, the average current flowing in the leads of the tunnel junction is studied. Explicit results are given for the case of an applied voltage with a constant dc part and a sinusoidal ac part. The connection with standard dynamical Coulomb blockade theory for constant applied voltage is established. It is shown that an alternating voltage source reveals significant additional effects caused by the electromagnetic environment. The hallmark of the dynamical Coulomb blockade in ac driven devices is a suppression of higher harmonics of the current by the electromagnetic environment. The theory presented basically applies to all tunneling devices driven by alternating voltages.

  15. Self-driven jamming in growing microbial populations

    Science.gov (United States)

    Delarue, Morgan; Hartung, Jörn; Schreck, Carl; Gniewek, Pawel; Hu, Lucy; Herminghaus, Stephan; Hallatschek, Oskar

    2016-08-01

    In natural settings, microbes tend to grow in dense populations where they need to push against their surroundings to accommodate space for new cells. The associated contact forces play a critical role in a variety of population-level processes, including biofilm formation, the colonization of porous media, and the invasion of biological tissues. Although mechanical forces have been characterized at the single-cell level, it remains elusive how collective pushing forces result from the combination of single-cell forces. Here, we reveal a collective mechanism of confinement, which we call self-driven jamming, that promotes the build-up of large mechanical pressures in microbial populations. Microfluidic experiments on budding yeast populations in space-limited environments show that self-driven jamming arises from the gradual formation and sudden collapse of force chains driven by microbial proliferation, extending the framework of driven granular matter. The resulting contact pressures can become large enough to slow down cell growth, to delay the cell cycle in the G1 phase, and to strain or even destroy the micro-environment through crack propagation. Our results suggest that self-driven jamming and build-up of large mechanical pressures is a natural tendency of microbes growing in confined spaces, contributing to microbial pathogenesis and biofouling.

  16. Dynamic Obfuscation Algorithm based on Demand-Driven Symbolic Execution

    Directory of Open Access Journals (Sweden)

    Yubo Yang

    2014-06-01

    Full Text Available Dynamic code obfuscation technique increases the difficulty of dynamically reverse by the runtime confusion. Path explosion directly affects the efficiency and accuracy of dynamic symbolic analysis. Because of the defect, this paper presents a novel algorithm DDD (Demand-Driven Dynamic Obfuscation Algorithm by using the demand-driven theory of symbolic analysis. First, create a large number of invalid paths to mislead the result of symbolic analysis. Second, according to the demand-driven theory, create a specific execution path to protect the security of software. The design and implementation of the algorithm is based on the current popular and mature SMT (satisfiability model theory, and the experimental effects are tested by Z3 - the SMT solver and Pex - the symbolic execution test tools. The experimental results prove that the algorithm enhance the security of the program.

  17. A mobile design lab for user-driven innovation

    DEFF Research Database (Denmark)

    Christiansen, Ellen; Kanstrup, Anne Marie

    2007-01-01

    The paper presents the history and conceptual foundation for the Mobile Design Lab, ment to support both designers and users in the acts of user-driven innovation. The Mobile Design Lab is based on Vygotsky's theory of tool- and language-mediation, and was created in 2004 to support research...... and teaching of user driven innovation. Being itself an example of user-driven innovation it has taken shape of HCI design research projekcts, in which we have been involved since 2004. The first challenge was to get 'out of the lab', the next to get 'out of the head', and finally we are currently working...... to get 'into the street'. To support these moves might seem simple, but it is in practice not at all easy. As for today the Mobile Design Lab comprises tools and techniques for categorization, articulation and concretizatoin in design projects involving lead users as well as ordinary users, and invisible...

  18. Performance-Driven Interface Contract Enforcement for Scientific Components

    Energy Technology Data Exchange (ETDEWEB)

    Dahlgren, T L

    2007-10-01

    Performance-driven interface contract enforcement research aims to improve the quality of programs built from plug-and-play scientific components. Interface contracts make the obligations on the caller and all implementations of the specified methods explicit. Runtime contract enforcement is a well-known technique for enhancing testing and debugging. However, checking all of the associated constraints during deployment is generally considered too costly from a performance stand point. Previous solutions enforced subsets of constraints without explicit consideration of their performance implications. Hence, this research measures the impacts of different interface contract sampling strategies and compares results with new techniques driven by execution time estimates. Results from three studies indicate automatically adjusting the level of checking based on performance constraints improves the likelihood of detecting contract violations under certain circumstances. Specifically, performance-driven enforcement is better suited to programs exercising constraints whose costs are at most moderately expensive relative to normal program execution.

  19. Integrating Autonomic Grid Components and Process-Driven Business Applications

    Science.gov (United States)

    Weigold, Thomas; Aldinucci, Marco; Danelutto, Marco; Getov, Vladimir

    Today's business applications are increasingly process driven, meaning that the main application logic is executed by a dedicate process engine. In addition, component-oriented software development has been attracting attention for building complex distributed applications. In this paper we present the experiences gained from building a process-driven biometric identification application which makes use of Grid infrastructures via the Grid Component Model (GCM). GCM, besides guaranteeing access to Grid resources, supports autonomic management of notable parallel composite components. This feature is exploited within our biometric identification application to ensure real time identification of fingerprints. Therefore, we briefly introduce the GCM framework and the process engine used, and we describe the implementation of the application using autonomic GCM components. Finally, we summarize the results, experiences, and lessons learned focusing on the integration of autonomic GCM components and the process-driven approach.

  20. Epidemic Dynamics On Information-Driven Adaptive Networks

    CERN Document Server

    Zhan, Xiu-Xiu; Sun, Gui-Quan; Zhang, Zi-Ke

    2015-01-01

    can evolve simultaneously. For the information-driven adaptive process, susceptible (infected) individuals who have abilities to recognize the disease would break the links of their infected (susceptible) neighbors to prevent the epidemic from further spreading. Simulation results and numerical analyses based on the pairwise approach indicate that the information-driven adaptive process can not only slow down the speed of epidemic spreading, but can also diminish the epidemic prevalence at the final state significantly. In addition, the disease spreading and information diffusion pattern on the lattice give a visual representation about how the disease is trapped into an isolated field with the information-driven adaptive process. Furthermore, we perform the local bifurcation analysis on four types of dynamical regions, including healthy, oscillatory, bistable and endemic, to understand the evolution of the observed dynamical behaviors. This work may shed some lights on understanding how information affects h...

  1. Note: A table-top blast driven shock tube

    Science.gov (United States)

    Courtney, Michael W.; Courtney, Amy C.

    2010-12-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer that explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  2. A Table-top Blast Driven Shock Tube

    CERN Document Server

    Courtney, Michael; 10.1063/1.3518970

    2011-01-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer which explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  3. Lid-driven cavity flow of viscoelastic liquids

    CERN Document Server

    Sousa, R G; Afonso, A M; Pinho, F T; Oliveira, P J; Morozov, A; Alves, M A

    2016-01-01

    The lid-driven cavity flow is a well-known benchmark problem for the validation of new numerical methods and techniques. In experimental and numerical studies with viscoelastic fluids in such lid-driven flows, purely-elastic instabilities have been shown to appear even at very low Reynolds numbers. A finite-volume viscoelastic code, using the log-conformation formulation, is used in this work to probe the effect of viscoelasticity on the appearance of such instabilities in two-dimensional lid-driven cavities for a wide range of aspect ratios (0.125 < height/length < 4.0), at different Deborah numbers under creeping-flow conditions and to understand the effects of regularization of the lid velocity. The effect of the viscoelasticity on the steady-state results and on the critical conditions for the onset of the elastic instabilities are described and compared to experimental results.

  4. Performance-Driven Interface Contract Enforcement for Scientific Components

    Energy Technology Data Exchange (ETDEWEB)

    Dahlgren, Tamara Lynn [Univ. of California, Davis, CA (United States)

    2008-01-01

    Performance-driven interface contract enforcement research aims to improve the quality of programs built from plug-and-play scientific components. Interface contracts make the obligations on the caller and all implementations of the specified methods explicit. Runtime contract enforcement is a well-known technique for enhancing testing and debugging. However, checking all of the associated constraints during deployment is generally considered too costly from a performance stand point. Previous solutions enforced subsets of constraints without explicit consideration of their performance implications. Hence, this research measures the impacts of different interface contract sampling strategies and compares results with new techniques driven by execution time estimates. Results from three studies indicate automatically adjusting the level of checking based on performance constraints improves the likelihood of detecting contract violations under certain circumstances. Specifically, performance-driven enforcement is better suited to programs exercising constraints whose costs are at most moderately expensive relative to normal program execution.

  5. Traffic-driven epidemic spreading in correlated networks

    CERN Document Server

    Yang, Han-Xin; Lai, Ying-Cheng

    2015-01-01

    In spite of the extensive previous efforts on traffic dynamics and epidemic spreading in complex networks, the problem of traffic-driven epidemic spreading on {\\em correlated} networks has not been addressed. Interestingly, we find that the epidemic threshold, a fundamental quantity underlying the spreading dynamics, exhibits a non-monotonic behavior in that it can be minimized for some critical value of the assortativity coefficient, a parameter characterizing the network correlation. To understand this phenomenon, we use the degree-based mean-field theory to calculate the traffic-driven epidemic threshold for correlated networks. The theory predicts that the threshold is inversely proportional to the packet-generation rate and the largest eigenvalue of the betweenness matrix. We obtain consistency between theory and numerics. Our results may provide insights into the important problem of controlling/harnessing real-world epidemic spreading dynamics driven by traffic flows.

  6. First International Conference on Cable-Driven Parallel Robots

    CERN Document Server

    Pott, Andreas; Cable-Driven Parallel Robots

    2013-01-01

    This publication presents the outcome of the "First International Conference on Cable-Driven Parallel Robots" in 2012. This is the first conference to bring together the cable robot community and dedicate a forum for the international experts of this field. It contains the Know-how, ideas and experiences of active researchers developing cable-driven robots. The book presents the state of the art, including summarizing contributions and latest research results and, where relevant, the future outlook. The book covers the essential topics for cable-driven robots: classification and definition, kinematics, workspace analysis, cable modeling, control and calibration, design methodology, hardware/prototype development, experimental evaluation, application reports and new application concepts.

  7. Deployment/Retrieval Modeling of Cable-Driven Parallel Robot

    Directory of Open Access Journals (Sweden)

    Q. J. Duan

    2010-01-01

    Full Text Available A steady-state dynamic model of a cable in air is put forward by using some tensor relations. For the dynamic motion of a long-span Cable-Driven Parallel Robot (CDPR system, a driven cable deployment and retrieval mathematical model of CDPR is developed by employing lumped mass method. The effects of cable mass are taken into account. The boundary condition of cable and initial values of equations is founded. The partial differential governing equation of each cable is thus transformed into a set of ordinary differential equations, which can be solved by adaptive Runge-Kutta algorithm. Simulation examples verify the effectiveness of the driven cable deployment and retrieval mathematical model of CDPR.

  8. Lithium ion beam driven hohlraums for PBFA II

    Energy Technology Data Exchange (ETDEWEB)

    Dukart, R.J.

    1994-05-06

    In our light ion inertial confinement fusion (ICF) program, fusion capsules are driven with an intense x-ray radiation field produced when an intense beam of ions penetrates a radiation case and deposits energy in a foam x-ray conversion region. A first step in the program is to generate and measure these intense fields on the Particle Beam Fusion Accelerator II (PBFA II). Our goal is to generate a 100-eV radiation temperature in lithium ion beam driven hohlraums, the radiation environment which will provide the initial drive temperature for ion beam driven implosion systems designed to achieve high gain. In this paper, we describe the design of such hohlraum targets and their predicted performance on PBFA II as we provide increasing ion beam intensities.

  9. Patron-driven acquisitions history and best practices

    CERN Document Server

    2011-01-01

    About 40 percent of the books academic libraries purchase in traditional ways never circulate and another 40 percent circulate fewer than three times. By contrast, patron-driven acquisition allows a library to borrow or buy books only when a patron needs them. In a typical workflow, the library imports bibliographic records into its catalogue at no cost. When a patron finds a patron-driven record in the course of research, a short-term loan can allow him to borrow the book, and the transaction charge to the library will be a small percentage of the list price. Typically, a library will automatically buy a book on a third or fourth use. The contributions in this volume, written by experts, describe the genesis and brief history of patron-driven acquisitions, its current status, and its promise.

  10. Artificial cognitive memory—changing from density driven to functionality driven

    Science.gov (United States)

    Shi, L. P.; Yi, K. J.; Ramanathan, K.; Zhao, R.; Ning, N.; Ding, D.; Chong, T. C.

    2011-03-01

    Increasing density based on bit size reduction is currently a main driving force for the development of data storage technologies. However, it is expected that all of the current available storage technologies might approach their physical limits in around 15 to 20 years due to miniaturization. To further advance the storage technologies, it is required to explore a new development trend that is different from density driven. One possible direction is to derive insights from biological counterparts. Unlike physical memories that have a single function of data storage, human memory is versatile. It contributes to functions of data storage, information processing, and most importantly, cognitive functions such as adaptation, learning, perception, knowledge generation, etc. In this paper, a brief review of current data storage technologies are presented, followed by discussions of future storage technology development trend. We expect that the driving force will evolve from density to functionality, and new memory modules associated with additional functions other than only data storage will appear. As an initial step toward building a future generation memory technology, we propose Artificial Cognitive Memory (ACM), a memory based intelligent system. We also present the characteristics of ACM, new technologies that can be used to develop ACM components such as bioinspired element cells (silicon, memristor, phase change, etc.), and possible methodologies to construct a biologically inspired hierarchical system.

  11. Data-Driven Design to Production and Operation

    Directory of Open Access Journals (Sweden)

    Henriette Bier

    2014-11-01

    Full Text Available Digital technology has introduced in the last decades data-driven representational and generative methodologies based on principles such as parametric definition and algorithmic processing. In this context, the 15th Footprint issue examines the development of data-driven techniques such as digital drawing, modelling, and simulation with respect to their relationship to design. The data propelling these techniques may consist of qualitative or quantitative values and relations that are algorithmically processed. However, the focus here is not on each technique and its respective representational and generative aspects, but on the interface between these techniques and design conceptualisation, materialization, and use.

  12. System Driven by Correlated Gaussian Noises Related with Disorder

    Institute of Scientific and Technical Information of China (English)

    LI Jing-Hui

    2007-01-01

    A system driven by correlated Gaussian noises related with disorder is investigated. The Fokker-Planck equation (FPE) for the system is derived. Using the FPE derived, some systems driven by correlated Gaussian noises related with disorder can be investigated for Brownian motors, nonequilibrium transition, resonant activation,stochastic resonance, and so on. We only give one example: i.e., using the FPE derived, we study the resonant activation for a single motor protein model with correlated noises related to disorder. Since the correlated noise related to disorder usually exists with the friction, for the temperature, and so on, our results have generic physical meanings for physics, chemistry, biology and other sciences.

  13. A new barotropic model of the wind-driven circulation

    Institute of Scientific and Technical Information of China (English)

    张庆华; 曲媛媛; 李坚克

    1999-01-01

    Rationalized by the observational circulation pattern in the upper ocean of the North Pacific, meridional friction term is first incorporated in a barotropic theoretical model of the wind-driven circulation. The governing potential vortieity equation thence has β term and wind stress curl term (the two of the Sverdrup balance), zonal friction term and meridional friction term. The analytical solution satisfactorily captures many important features of the wind-driven circulation in the North Pacific: Kuroshio, Oyashio, Kuroshio extension, North Equatorial Current, and especially the eastern boundary currents in the North Pacific, i.e. California current and Alaska current.

  14. Process-Driven SOA Patterns for Aligning Business and IT

    CERN Document Server

    Hentrich, Carsten

    2011-01-01

    Process-Driven SOA: Patterns for Aligning Business and IT supplies detailed guidance on how to design and build software architectures that follow the principles of business-IT alignment. It illustrates the design process using proven patterns that address complex business/technical scenarios, where integrated concepts of service-oriented architecture (SOA), Business Process Management (BPM), and Event-Driven Architecture (EDA) are required. The book demonstrates that SOA is not limited to technical issues but instead, is a holistic challenge where aspects of SOA, EDA, and BPM must be addresse

  15. Viscoelastic Suppression of Gravity-Driven Counterflow Instability

    CERN Document Server

    Beiersdorfer, P; Layne, D; Magee, E W

    2010-01-01

    Attempts to achieve ``top kill'' of actively flowing oil wells by insertion of dense drilling ``muds'', i.e., slurries of dense minerals, from above will fail if the Kelvin-Helmholtz instability in the gravity-driven counterflow produces turbulence that breaks up the denser fluid into small droplets. Here we estimate the droplet size to be sub-mm for fast flows and suggest the addition of a shear-thickening polymer to suppress turbulence. Laboratory experiments show a progression from droplet formation to complete turbulence suppression at the relevant high velocities, illustrating rich new physics accessible by using a shear-thickening liquid in gravity driven counter-streaming flows.

  16. Model-driven and software product line engineering

    CERN Document Server

    Royer, Jean-Claude

    2013-01-01

    Many approaches to creating Software Product Lines have emerged that are based on Model-Driven Engineering. This book introduces both Software Product Lines and Model-Driven Engineering, which have separate success stories in industry, and focuses on the practical combination of them. It describes the challenges and benefits of merging these two software development trends and provides the reader with a novel approach and practical mechanisms to improve software development productivity.The book is aimed at engineers and students who wish to understand and apply software product lines

  17. Performance-Driven Interface Contract Enforcement for Scientific Components

    Energy Technology Data Exchange (ETDEWEB)

    Dahlgren, T

    2007-02-22

    Several performance-driven approaches to selectively enforce interface contracts for scientific components are investigated. The goal is to facilitate debugging deployed applications built from plug-and-play components while keeping the cost of enforcement within acceptable overhead limits. This paper describes a study of global enforcement using a priori execution cost estimates obtained from traces. Thirteen trials are formed from five, single-component programs. Enforcement experiments conducted using twenty-three enforcement policies are used to determine the nature of exercised contracts and the impact of a variety of sampling strategies. Performance-driven enforcement appears to be best suited to programs that exercise moderately expensive contracts.

  18. Exponentially Slow Heating in Periodically Driven Many-Body Systems.

    Science.gov (United States)

    Abanin, Dmitry A; De Roeck, Wojciech; Huveneers, François

    2015-12-18

    We derive general bounds on the linear response energy absorption rates of periodically driven many-body systems of spins or fermions on a lattice. We show that, for systems with local interactions, the energy absorption rate decays exponentially as a function of driving frequency in any number of spatial dimensions. These results imply that topological many-body states in periodically driven systems, although generally metastable, can have very long lifetimes. We discuss applications to other problems, including the decay of highly energetic excitations in cold atomic and solid-state systems. PMID:26722939

  19. Computational fluid dynamics simulation of a rim driven thruster

    OpenAIRE

    Dubas, Aleksander J.; Bressloff, N. W.; Fangohr, H.; Sharkh, S.M.

    2011-01-01

    An electric rim driven thruster is a relatively new marine propulsion device that uses a motor in its casing to drive a propeller by its rim and the fluid dynamics associated with their operation have not been fully investigated. There are many interacting flow features that make up the flow field of a rim driven thruster that pose a number of challenges when it comes to simulating the device using computational fluid dynamics. The purpose of this work is to develop a computational fluid dyna...

  20. A capillary-driven micromixer: idea and fabrication

    International Nuclear Information System (INIS)

    Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis. (paper)