WorldWideScience

Sample records for antimatter driven p-b11

  1. Antimatter Driven Sail for Deep Space Missions

    Science.gov (United States)

    Howe, Steven D.; Jackson, Gerald P.

    2005-02-01

    The concept of the Antimatter Driven Sail (ADS) has been examined in three major areas: Mission Architecture, Subsystem Technologies, and a Technology Roadmap. The Mission Architecture effort has focused on developing an integrated systems model to evaluate the performance of the entire spacecraft for a mission. The Subsystem Technologies investigation examined 1) the fundamental reactions between the antiprotons and the sail material and the subsequent momentum transfer, 2) a concept for storing antihydrogen at high densities, and 3) an entirely new concept for electrical power production. The new electrical-power concept may have applicability to nearer-term space missions as a power supply if the availability of antiprotons becomes common. In developing the Technology Roadmap, we examined the potential 1) for using recent developments in antiproton storage and antihydrogen formation to create a path to ultra-high density antihydrogen storage, and 2) for increasing production of antiprotons by modifying the existing Fermilab facility. Our system analysis indicates that a 10 kg instrument pay load could be sent to 250 AU in 10 years using 30 milligrams of antihydrogen. This amount of antimatter is clearly within the production potential of the US within the next 40 years using currently accepted accelerator technologies. Major aspects of the architecture remain to be investigated but the first-cut assessment of the mission profile, the subsystem technologies, and the technology development path have all been identified. The antimatter driven sail may in-fact allow humanity to consider sending probes to the stars.

  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. 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.

  7. 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.

  8. 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.

  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. 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

  11. Antimatter in the classroom

    CERN Document Server

    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. “...

  12. 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."

  13. 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.

  14. 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...

  15. 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.)

  16. 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...

  17. Antimatter-Gravity Couplings, and Lorentz Symmetry

    CERN Document Server

    Tasson, Jay D

    2015-01-01

    Implications of possible CPT and Lorentz violation for antimatter-gravity experiments as well as other antimatter tests are considered in the context of the general field-theory-based framework of the Standard-Model Extension (SME).

  18. 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.

  19. 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.

  20. 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.)

  1. Interchange instability and transport in matter-antimatter plasmas

    CERN Document Server

    Kendl, Alexander; Wiesenberger, Matthias; Held, Markus

    2016-01-01

    Symmetric electron-positron plasmas in inhomogeneous magnetic fields are intrinsically subject to interchange instability and transport. Scaling relations for the propagation velocity of density blob perturbations relevant to transport in isothermal magnetically confined electron-positron plasmas are deduced, including damping effects when Debye lengths are large compared to Larmor radii. The relations are verified by nonlinear full-F gyrofluid computations. Results are in favour of sufficient magnetic confinement for planned electron-positron plasma experiments. The model is generalised to other matter-antimatter plasmas. Magnetised electron-positron-proton-antiproton plasmas are susceptible to interchange driven local matter-antimatter separation, which can be expected to impede (so far unrealised) sustained laboratory magnetic confinement.

  2. 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...

  3. Measuring antimatter gravity with muonium

    Directory of Open Access Journals (Sweden)

    Kaplan Daniel M.

    2015-01-01

    Full Text Available The gravitational acceleration of antimatter, ḡ, 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 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 ḡ 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 first measurement of the gravitational acceleration of antimatter.

  4. Measuring Antimatter Gravity with Muonium

    CERN Document Server

    Kaplan, Daniel M; Mancini, Derrick; Phillips, James D; Phillips, Thomas J; Roberts, Thomas J; Terry, Jeff

    2014-01-01

    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 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 first...

  5. 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)

  6. 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...

  7. 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)

  8. 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.

  9. 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.

  10. 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...

  11. 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...

  12. Mirror Symmetry of Matter and Antimatter

    Science.gov (United States)

    Close, Robert

    2010-03-01

    Physical processes involving weak interactions have mirror images which can be mimicked in the natural universe only by exchanging matter and antimatter. This experimental observation is easily explained by the hypothesis that spatial inversion exchanges matter and antimatter. Yet according to conventional theory, the parity operator P does not exchange matter and antimatter but instead yields phenomena which have never been observed. We examine the conventional derivation of the Dirac parity operator and find that it is based on the speculative assumption that the unit imaginary is always a true scalar rather than a pseudoscalar. This assumption incorrectly requires that the matrix 0̂ preserve its sign under spatial inversion. This requirement results in a mixed-parity vector space defined relative to velocity, which is otherwise isomorphic to the spatial axes. We derive a new spatial inversion operator M (for mirroring) by requiring that for any set of orthogonal basis vectors, all three must have the same parity. A pseudoscalar unit imaginary is defined in terms of Dirac matrices. The M operator is a symmetry of the Dirac equation. It exchanges positive and negative energy eigenfunctions, consistent with all experimental evidence of mirror symmetry between matter and antimatter. This result provides a simple reason for the apparent absence in nature of mirror-like phenomena, such as right-handed neutrinos, which do not exchange matter and antimatter.

  13. The Mystery of the Missing Antimatter

    CERN Document Server

    Quinn, Helen R

    2008-01-01

    In the first fractions of a second after the Big Bang lingers a question at the heart of our very existence: why does the universe contain matter but almost no antimatter? The laws of physics tell us that equal amounts of matter and antimatter were produced in the early universe--but then, something odd happened. Matter won out over antimatter; had it not, the universe today would be dark and barren. But how and when did this occur? Helen Quinn and Yossi Nir guide readers into the very heart of this mystery--and along the way offer an exhilarating grand tour of cutting-edge physics. They explain both the history of antimatter and recent advances in particle physics and cosmology. And they discuss the enormous, high-precision experiments that particle physicists are undertaking to test the laws of physics at their most fundamental levels--and how their results reveal tantalizing new possibilities for solving this puzzle at the heart of the cosmos. The Mystery of the Missing Antimatter is at once a history of i...

  14. 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 International Linear Collider (ILC) and Compact Linear Collider (CLIC).

  15. Discovering Matter-Antimatter Asymmetries with GPUs

    CERN Document Server

    Reichert, Stefanie

    2015-01-01

    The search for matter-antimatter asymmetries requires highest precision analyses and thus very large datasets and intensive computing. This contribution discusses two complemen- tary approaches where GPU systems have been successfully exploited in this area. Both approaches make use of the CUDA Thrust library which can be used on supported GPUs. The first approach is a generic search for local asymmetries in phase-space distributions of matter and antimatter particle decays. This powerful analysis method has never been used to date due to its high demand in CPU time. The second approach uses the GooFit framework, which is a generic fitting framework that exploits massive parallelisation on GPUs

  16. 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)

  17. 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.

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. The Matter-Antimatter Asymmetry of the Universe

    CERN Document Server

    Stecker, F W

    2002-01-01

    I will give here an overview of the present observational and theoretical situation regarding the question of the matter-antimatter asymmetry of the universe and the related question of the existence of antimatter on a cosmological scale. I will also give a simple discussion of the role of CP violation in this subject.

  6. Matter-Antimatter Asymmetry - Aspects at Low Energy

    CERN Document Server

    Willmann, Lorenz

    2015-01-01

    The apparent dominance of matter over antimatter in our universe is an obvious and puzzling fact which cannot be adequately explained in present physical frameworks that assume matter-antimatter symmetry at the big bang. However, our present knowledge of starting conditions and of known sources of CP violation are both insufficient to explain the observed asymmetry. Therefore ongoing research on matter-antimatter differences is strongly motivated as well as attempts to identify viable new mechanisms that could create the present asymmetry. Here we concentrate on possible precision experiments at low energies towards a resolution of this puzzle.

  7. 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.

  8. Is a symmetric matter-antimatter universe excluded?

    CERN Document Server

    Baur, Julien; Von Ballmoos, Peter

    2015-01-01

    We consider a non-standard cosmological model in which the universe contains as much matter as antimatter on large scales and presents a local baryon asymmetry. A key ingredient in our approach is that the baryon density distribution follows Gaussian fluctuations around a null value $\\eta = 0$. Spatial domains featuring a positive (resp. negative) baryonic density value constitute regions dominated by matter (resp. antimatter). At the domains' annihilation interface, the typical density is going smoothly to zero, rather than following an abrupt step as assumed in previous symetric matter-antimatter models. As a consequence, the Cosmic Diffuse Gamma Background produced by annihilation is drastically reduced, allowing to easily pass COMPTEL's measurements limits. Similarly the Compton $y$ distorsion and CMB 'ribbons' are lowered by an appreciable factor. Therefore this model essentially escape previous constrainst on symetric matter-antimatter models. However, we produce an estimation of the CMB temperature flu...

  9. 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).

  10. 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.

  11. 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.

  12. Gravity Effects on Antimatter in the Standard-Model Extension

    CERN Document Server

    Tasson, Jay D

    2015-01-01

    The gravitational Standard-Model Extension (SME) is the general field-theory based framework for the analysis of CPT and Lorentz violation. In this work we summarize the implications of Lorentz and CPT violation for antimatter gravity in the context of the SME. Implications of various attempts to place indirect limits on anomalous antimatter gravity are considered in the context of SME-based models.

  13. Fusion Reactions and Matter-Antimatter Annihilation for Space Propulsion

    Science.gov (United States)

    2005-07-13

    which are essentially impossible using chemical or even nuclear thermal rockets . One example is a solar impact mission, which requires the rocket to... thermal rockets . All of those missions could be performed by fusion or antimatter rockets with a mass ratio of 5:1 or less. Table I - Mass...roughly equivalent to that of the nuclear thermal rocket (Isp ~ 103 sec) due to temperature limitations of the solid. However, the antimatter energy

  14. Antimatter in the Direct-Action Theory of Fields

    Directory of Open Access Journals (Sweden)

    Ruth E. Kastner

    2016-01-01

    Full Text Available 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. Quanta 2016; 5: 12–18.

  15. 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.

  16. Gravitationally Coupled Dirac Equation for Antimatter

    CERN Document Server

    Jentschura, U D

    2013-01-01

    The coupling of antimatter to gravity is of general interest because of conceivable cosmological consequences ("surprises") related to dark energy and the cosmological constant. Here, we revisit the derivation of the gravitationally coupled Dirac equation and find that the prefactor of a result given previously in [D.R. Brill and J.A. Wheeler, Rev. Mod. Phys., vol. 29, p. 465 (1957)] for the affine connection matrix is in need of a correction. We also discuss the conversion the curved-space Dirac equation from East-Coast to West-Coast conventions, in order to bring the gravitationally coupled Dirac equation to a form where it can easily be unified with the electromagnetic coupling as it is commonly used in modern particle physics calculations. The Dirac equation describes anti-particles as negative-energy states. We find a symmetry of the gravitationally coupled Dirac equation, which connects particle and antiparticle solutions for a general space-time metric of the Schwarzschild type and implies that particl...

  17. 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 '...

  18. 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...

  19. Why is the universe more partial to mater than antimatter?

    CERN Multimedia

    2006-01-01

    "B factory experiments at the Stanford Linear Accelerator (SLAC) in the USA and at the High Energy Accelerator Research Organization (KEK) in Japan have reached a new milestone in the quest to understand the matter-antimatter imbalance in our universe.

  20. 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…

  1. Turning the Star Trek Dream into Reality by Understanding Matter & Antimatter

    Science.gov (United States)

    Hansen, Norm

    2002-04-01

    People are going to learn all about matter and antimatter. Where matter and antimatter comes from. Where antimatter exists within our solar system. What the Periodic Table of Matter-AntiMatter Elements looks like. What each of the 109 antimatter element's nuclear, physical, and chemical characteristics are. How much energy is produced from matter and antimatter. And what needs to be done to turn the Star Trek Dream into Reality. The Milky Way Galaxy is composed of matter and antimatter. At the center of the galaxy, there are two black holes. One black hole is composed of matter; and the other is antimatter. The black holes are ejecting matter and antimatter into space forming a halo and spiral arms of matter & antimatter stars. The sun is one of the billions of stars that are composed of matter. There are a similar number of antimatter stars. Our Solar System contains the sun, earth, planets, and asteroids that are composed of matter, and comets that are composed of antimatter. When galactic antimatter enters our solar system, the antimatter is called comets. Astronomers have observed hundred of comets orbiting the sun and are finding new comets every year. During the last century, mass destruction has resulted when antimatter collided with Jupiter and Earth. How Humanity deals with the opportunities and dangers of antimatter will determine our destiny. Mankind has known about comets destructive power for thousands of years going back to the days of antiquity. Did comets have anything to do with the disappearance of Atlantis over twelve thousand years ago? We may never know; but is there a similar situation about to take place? Scientists have been studying antimatter by producing, storing, and colliding small quantities at national laboratories for several decades. Symmetry exists between matter and antimatter. Science and Technology provides unlimited opportunities to benefit humanity. Antimatter can be used, as a natural source of energy, to bring every country

  2. Through the Looking Glass: What's the Matter with Antimatter?

    Science.gov (United States)

    Kirkby, David

    2003-04-01

    In May 1999, a new generation of particle-physics experiments recorded the first collisions from some of the most intense particle beams ever created: BABAR at the Stanford Linear Accelerator Center and BELLE at KEK in Japan. The ultimate goal of these experiments is to shed new light on one of the least understood aspects of particle physics: Why does the universe contain more matter than antimatter today? We do this by testing our understanding (the Standard Model) of matter-antimatter asymmetries in the oscillations and decays of b quarks. The first results from the new experiments confirmed the Standard Model. This was a triumph for the theory, but deepens the puzzle since the Standard Model cannot explain the size of the observed asymmetry in the universe today. In this talk, I will review the latest results from the new experiments and highlight some interesting prospects for future progress.

  3. 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...

  4. 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...

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. Star Trek meets the Big Bang curiosity is leading scientists on a mission to explain antimatter

    CERN Multimedia

    Cookson, C

    1998-01-01

    Next year, scientists at CERN will inaugurate the world's first 'antimatter factory'. The 'Antiproton Decelerator' will make more than 2000 atoms of anti-hydrogen an hour and contain them in a magnetic trap within a vacuum (1 page).

  12. 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...

  13. 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...

  14. 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; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chatzikonstantinidis, Georgios; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chobanova, Veronika; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Costa Sobral, Cayo Mar; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Da Cunha Marinho, Franciole; Dall'Occo, Elena; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Aguiar Francisco, Oscar; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Serio, Marilisa; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Dijkstra, Hans; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dungs, Kevin; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Déléage, Nicolas; Easo, Sajan; Ebert, Marcus; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Farley, Nathanael; Farry, Stephen; Fay, Robert; Fazzini, Davide; Ferguson, Dianne; Fernandez Albor, Victor; Fernandez Prieto, Antonio; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fini, Rosa Anna; Fiore, Marco; Fiorini, Massimiliano; 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, V.V.; 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; Kecke, Matthieu; Kelsey, Matthew; Kenyon, Ian; Kenzie, Matthew; Ketel, Tjeerd; Khairullin, Egor; Khanji, Basem; Khurewathanakul, Chitsanu; Kirn, Thomas; Klaver, Suzanne; Klimaszewski, Konrad; Koliiev, Serhii; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Kozachuk, Anastasiia; Kozeiha, Mohamad; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krokovny, Pavel; Kruse, Florian; Krzemien, Wojciech; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kuonen, Axel Kevin; Kurek, Krzysztof; Kvaratskheliya, Tengiz; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lanfranchi, Gaia; Langenbruch, Christoph; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Leflat, Alexander; Lefrançois, Jacques; Lefèvre, Regis; Lemaitre, Florian; Lemos Cid, Edgar; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Liu, Xuesong; 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; Mogini, Andrea; Molina Rodriguez, Josue; Monroy, Ignacio Alberto; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Mulder, Mick; Mussini, Manuel; Müller, Dominik; Müller, Janine; Müller, Katharina; Müller, Vanessa; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nandi, Anita; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen-Mau, Chung; Nieswand, Simon; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Oldeman, Rudolf; Onderwater, Gerco; Otalora Goicochea, Juan Martin; Otto, Adam; Owen, Patrick; Oyanguren, Maria Aranzazu; Pais, Preema Rennee; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parker, William; Parkes, Christopher; Passaleva, Giovanni; Pastore, Alessandra; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petrov, Aleksandr; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pikies, Malgorzata; Pinci, Davide; Pistone, Alessandro; Piucci, Alessio; Playfer, Stephen; Plo Casasus, Maximo; Poikela, Tuomas; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Pomery, Gabriela Johanna; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Poslavskii, Stanislav; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Rachwal, Bartolomiej; Rademacker, Jonas; Rama, Matteo; Ramos Pernas, Miguel; Rangel, Murilo; Raniuk, Iurii; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; 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; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sergi, Antonino; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Siddi, Benedetto Gianluca; Silva Coutinho, Rafael; Silva de Oliveira, Luiz Gustavo; Simi, Gabriele; Simone, Saverio; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Eluned; Smith, Iwan Thomas; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Stefko, Pavol; Stefkova, Slavorima; Steinkamp, Olaf; Stemmle, Simon; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Syropoulos, Vasileios; Szczekowski, Marek; Szumlak, Tomasz; T'Jampens, Stephane; Tayduganov, Andrey; Tekampe, Tobias; Tellarini, Giulia; Teubert, Frederic; Thomas, Eric; van Tilburg, Jeroen; Tilley, Matthew James; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Toriello, Francis; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Traill, Murdo; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tully, Alison; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valassi, Andrea; Valat, Sebastien; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vecchi, Stefania; van Veghel, Maarten; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Venkateswaran, Aravindhan; Vernet, Maxime; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Volkov, Vladimir; Vollhardt, Achim; Voneki, Balazs; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Vázquez Sierra, Carlos; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wang, Jianchun; Ward, David; Wark, Heather Mckenzie; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wicht, Jean; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Williams, Timothy; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wraight, Kenneth; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yin, Hang; Yu, Jiesheng; Yuan, Xuhao; Yushchenko, Oleg; Zarebski, Kristian Alexander; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhang, Yu; Zhelezov, Alexey; Zheng, Yangheng; Zhokhov, Anatoly; Zhu, Xianglei; Zhukov, Valery; Zucchelli, Stefano

    2017-01-01

    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.

  15. 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...

  16. Probing antimatter gravity - The AEGIS experiment at CERN

    Science.gov (United States)

    Kellerbauer, A.; Aghion, S.; Amsler, C.; Ariga, A.; Ariga, T.; Bonomi, G.; Bräunig, P.; Bremer, J.; Brusa, R. S.; Cabaret, L.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Chlouba, K.; Cialdi, S.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Dudarev, A.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Holmestad, H.; Huse, T.; Jordan, E.; Kimura, M.; Koettig, T.; Krasnický, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Lehner, S.; Liberadzka, J.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Mazzotta, Z.; Nebbia, G.; Nédélec, P.; Oberthaler, M.; Pacifico, N.; Pagano, D.; Penasa, L.; Petráček, V.; Pistillo, C.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Rienäcker, B.; Røhne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Smestad, L.; Sorrentino, F.; Špaček, M.; Storey, J.; Strojek, I. M.; Testera, G.; Tietje, I.; Widmann, E.; Yzombard, P.; Zavatarelli, S.; Zmeskal, J.; Zurlo, N.

    2016-11-01

    The weak equivalence principle states that the motion of a body in a gravitational field is independent of its structure or composition. This postulate of general relativity has been tested to very high precision with ordinary matter, but no relevant experimental verification with antimatter has ever been carried out. The AEGIS experiment will measure the gravitational acceleration of antihydrogen to ultimately 1% precision. For this purpose, a pulsed horizontal antihydrogen beam with a velocity of several 100 m s-1 will be produced. Its vertical deflection due to gravity will be detected by a setup consisting of material gratings coupled with a position-sensitive detector, operating as a moiré deflectometer or an atom interferometer. The AEGIS experiment is installed at CERN's Antiproton Decelerator, currently the only facility in the world which produces copious amounts of low-energy antiprotons. The construction of the setup has been going on since 2010 and is nearing completion. A proof-of-principle experiment with antiprotons has demonstrated that the deflection of antiparticles by a few μm due to an external force can be detected. Technological and scientific development pertaining to specific challenges of the experiment, such as antihydrogen formation by positronium charge exchange or the position-sensitive detection of antihydrogen annihilations, is ongoing.

  17. 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

  18. 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.

  19. 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.

  20. 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).

  1. 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)

  2. 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)

  3. 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...

  4. 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.

  5. Prospects for studies of the free fall and gravitational quantum states of antimatter

    CERN Document Server

    Dufour, Gabriel; Crivelli, Paolo; Debu, Pascal; Lambrecht, Astrid; Nesvizhevsky, Valery V; Reynaud, Serge; Voronin, Alexei Yu; Wall, Thomas E

    2014-01-01

    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 in 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...

  6. Gravitationally neutral dark matter-dark antimatter universe crystal with epochs of decelerated and accelerated expansion

    Science.gov (United States)

    Gribov, I. A.; Trigger, S. A.

    2016-11-01

    A large-scale self-similar crystallized phase of finite gravitationally neutral universe (GNU)—huge GNU-ball—with spherical 2D-boundary immersed into an endless empty 3D- space is considered. The main principal assumptions of this universe model are: (1) existence of stable elementary particles-antiparticles with the opposite gravitational “charges” (M+gr and M -gr), which have the same positive inertial mass M in = |M ±gr | ≥ 0 and are equally presented in the universe during all universe evolution epochs; (2) the gravitational interaction between the masses of the opposite charges” is repulsive; (3) the unbroken baryon-antibaryon symmetry; (4) M+gr-M-gr “charges” symmetry, valid for two equally presented matter-antimatter GNU-components: (a) ordinary matter (OM)-ordinary antimatter (OAM), (b) dark matter (DM)-dark antimatter (DAM). The GNU-ball is weightless crystallized dust of equally presented, mutually repulsive (OM+DM) clusters and (OAM+DAM) anticlusters. Newtonian GNU-hydrodynamics gives the observable spatial flatness and ideal Hubble flow. The GNU in the obtained large-scale self-similar crystallized phase preserves absence of the cluster-anticluster collisions and simultaneously explains the observable large-scale universe phenomena: (1) the absence of the matter-antimatter clusters annihilation, (2) the self-similar Hubble flow stability and homogeneity, (3) flatness, (4) bubble and cosmic-net structures as 3D-2D-1D decrystallization phases with decelerative (a ≤ 0) and accelerative (a ≥ 0) expansion epochs, (5) the dark energy (DE) phenomena with Λ VACUUM = 0, (6) the DE and DM fine-tuning nature and predicts (7) evaporation into isolated huge M±gr superclusters without Big Rip.

  7. Dark Antimatter as a Galactic Heater: X-rays from the Core of our Galaxy

    CERN Document Server

    Forbes, M M N; Forbes, Michael McNeil; Zhitnitsky, Ariel R.

    2006-01-01

    Several independent observations of the Galactic core suggest hitherto unexplained sources of energy. We show that dark matter in the form of dense antimatter droplets provides a natural site for electron and proton annihilation, providing 511 keV photons, gamma-rays, and energy that sustains thermal X-ray radiation. Such a picture not only identifies the dark matter in our universe, but allows X-ray observations to directly probe the matter distribution in our Galaxy.

  8. The Janus Cosmological Model (JCM) : An answer to the missing cosmological antimatter

    Science.gov (United States)

    D'Agostini, Gilles; Petit, Jean-Pierre

    2017-01-01

    Cosmological antimatter absence remains unexplained. Twin universes 1967 Sakarov's model suggests an answer: excess of matter and anti-quarks production in our universe is balanced by equivalent excess of antimatter and quark in twin universe. JCM provides geometrical framework, with a single manifold , two metrics solutions of two coupled field equations, to describe two populations of particles, one with positive energy-mass and the other with negative energy-mass : the `twin matter'. In a quantum point of view, it's a copy of the standard matter but with negative mass and energy. The matter-antimatter duality holds in both sectors. The standard and twin matters do not interact except through the gravitational coupling expressed in field equations. The twin matter is unobservable from matter-made apparatus. Field equations shows that matter and twin matter repel each other. Twin matter surrounding galaxies explains their confinement (dark matter role) and, in the dust universe era, mainly drives the process of expansion of the positive sector, responsible of the observed acceleration (dark energy role).

  9. 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.

  10. 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.

  11. 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.

  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. 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...

  14. 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.

  15. 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.

  16. 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...

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

    Science.gov (United States)

    Panther, Fiona H.; Crocker, Roland M.; Seitenzahl, Ivo R.; Ruiter, Ashley J.

    2017-01-01

    The Milky Way Galaxy glows with the soft gamma ray emission resulting from the annihilation of ~5 × 1043 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 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 and distribution of positrons we see annihilating in the Galaxy through the decay of 44Ti synthesised in these events. Such 44Ti production simultaneously addresses the observed abundance of 44Ca, the 44Ti decay product, in solar system material.

  18. 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...

  19. A radial Time Projection Chamber for the ALPHA-g antimatter gravity measurement at CERN

    Science.gov (United States)

    Martin, Lars; Amaudruz, Pierre-André; Bishop, Daryl; Capra, Andrea; Fujiwara, Makoto; Henderson, Robert; Kurchaninov, Leonid; Menary, Scott; Olchanski, Konstantin

    2016-09-01

    Antimatter is believed to be affected by gravity in exactly the same way as ordinary matter for a variety of good reasons, however this has never been measured directly. The ALPHA-g project is a new antihydrogen trap based on the previous ALPHA design (Antihydrogen Laser Physics Apparatus, the first experiment to trap antihydrogen in 2010). As in previous ALPHA experiments the trapped antihydrogen is detected via its charged annihilation products after switching off the trap. In order to be sensitive to small gravitational effects the setup extends more than 2 m in the vertical direction, requiring the particle detection system to cover a large volume with good tracking accuracy. The design chosen to replace the previous experiments' Silicon detectors is a radial field time-projection-chamber (rTPC) filled with an Argon/CO2 mixture. Results of extensive Garfield simulations and prototype tests are presented and evaluated in terms of vertex resolution and its consequences for the gravity measurement. Additionally we give a progress report on the construction of the final detector, which is scheduled to be on-line in late 2017 for a first stage up/down measurement.

  20. Zooming in on light relic neutralinos by direct detection and measurements of galactic antimatter

    CERN Document Server

    Bottino, A; Fornengo, N; Scopel, S

    2007-01-01

    The DAMA Collaboration has recently analyzed its data of the extensive WIMP direct search (DAMA/NaI) which detected an annual modulation, by taking into account the channelling effect which occurs when an ion traverses a detector with a crystalline structure. Among possible implications, this Collaboration has considered the case of a coherent WIMP-nucleus interaction and then derived the form of the annual modulation region in the plane of the WIMP-nucleon cross section versus the WIMP mass, using a specific modelling for the channelling effect. In the present paper we first show that light neutralinos fit the annual modulation region also when channelling is taken into account. To discuss the connection with indirect signals consisting in galactic antimatter, in our analysis we pick up a specific galactic model, the cored isothermal-sphere. In this scheme we determine the sets of supersymmetric models selected by the annual modulation regions and then prove that these sets are compatible with the available ...

  1. 反物质的质量特性研究%Mass-character research of antimatter

    Institute of Scientific and Technical Information of China (English)

    杨介甫

    2009-01-01

    分析了历史上的负几率、负能量和负质量的疑难,讨论了物质世界与反物质世界对称性的本质和湮灭的机理;给出一系列反粒子的反质量"-m";提出质量荷载概念:揭露发生湮灭反应的内在原因、条件和反物质具有反质量"-m";并进一步提出实验建议去检验反质量"-m".%The puzzles of negative probability, negative energy and negative mass in history are analysed, the essence of the symmetry of material world and antiworld, and the mechanism of the mass annihilation in annihilation reaction are discussed; Gives out: antimass "-m" of a series of antiparticles; advance the idea of mass-charge;expose the inherent cause, the condition of occurring annihilation radiation and all antimatter possess antimass "-m"; and puts forward experimental propositions to test the antimass"-m".

  2. Measurement of matter-antimatter differences in beauty baryon decays at LHCb

    CERN Multimedia

    Merli, Andrea

    2017-01-01

    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 $C\\!P$ violation. Using data from the LHCb experiment at the Large Hadron Collider, a search is made for $C\\!P$-violating asymmetries in the decay angle distributions of $\\Lambda_b^0$ baryons decaying to $p\\pi^-\\pi^+\\pi^-$ and $p\\pi^-K^+K^-m$ final states. These four-body hadronic decays are a promising place to search for sources of $C\\!P$ violation both within and beyond the Standard Model of particle physics. We find evidence for $C\\!P$ 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 $C\\!P$ violation in the baryon sector.

  3. 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.

  4. Review on anti-hypernucleus and anti-matter measurement%奇异反超核和反物质

    Institute of Scientific and Technical Information of China (English)

    马余刚; 陈金辉

    2015-01-01

    文章简要回顾了反物质研究历史,重点阐述了过去几年反物质研究领域的新结果,包括美国布鲁克海汶国家实验室的相对论重离子对撞机(RHIC)上观测到的首个反物质超核信号和迄今为止最重的反物质原子核——反氦4.同时,还介绍了欧洲核子中心(CERN)反氢原子捕捉的新结果以及宇宙空间站上α磁谱仪(AMS)二期的新进展等,并讨论了这些进展对认识物质结构的启示.%We briefly review the history of research on antimatter, focusing on new results from the past few years, namely, the observation of the first antimatter hypernucleus and the heavi-est antimatter nucleus so far, anti-helium-4, in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. In addition, we present new results on antihydrogen atom capture from the European Organization for Nuclear Research (CERN), and describe the progress of the Alpha Mag-netic Spectrometer phase-II experiment on the space station. Finally, the implications of these de-velopments for understanding the structure of matter are discussed.

  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. 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

  7. 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...

  8. Cosmic ray antiproton measurements in the 4-19 GeV energy range using the NMSU/WiZard-matter antimatter superconducting spectrometer 2 (MASS2)

    Energy Technology Data Exchange (ETDEWEB)

    Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Brunetti, M.T.; Codini, A.; Grimani, C. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); De Pascale, M.P. [Rome Univ. `Tor Vergata` (Italy)]|[INFN, Rome (Italy); Hof, M. [Siegen Univ. (Germany). Fachbereich Physik; Golden, R.L.; Stochaj, S.J. [New Mexico State Univ., Las Cruces, NM (United States). Particle Astrophysics Lab.; Brancaccio, F.M. [Florence Univ. (Italy)]|[INFN, Florence (Italy)

    1995-09-01

    The p/p-ratio from 4 to 19 GeV has been measured using the NMSU/WiZard balloon borne matter antimatter superconducting spectrometer (MASS2) instrument. This is the first confirmation of the cosmic ray antiproton component made in this energy range since their discovery in 1979. The MASS2 instrument is an updated version of the instrument flown in 1979. The p/p- ratio is 1.52x10{sup -}4.

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

    CERN Document Server

    Storey, J; Ahlén, O; Amsler, C; Ariga, A; Ariga, T; Belov, A.S; Bonomi, G; Bräunig, P; Bremer, J; Brusa, R.S; Burghart, G; Cabaret, L; Canali, C; Carante, M; Caravita, R; Castelli, F; Cerchiari, G; Cialdi, S; Comparat, D; Consolati, G; Dassa, L; 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; Hogan, S.D; Huse, T; Jordan, E; Jørgensen, L.V; Kaltenbacher, T; Kawada, J; Kellerbauer, A; Kimura, M; Knecht, A; Krasnický, D; Lagomarsino, V; Magnani, A; Mariazzi, S; Matveev, V.A; Merkt, F; Moia, F; Nebbia, G; Nédélec, P; Oberthaler, M.K; Pacifico, N; Petrácek, V; Pistillo, C; Prelz, F; Prevedelli, M; Regenfus, C; Riccardi, C; Røhne, O; Rotondi, A; Sandaker, H; Scampoli, P; Spacek, M; Subieta Vasquez, M.A; Testera, G; Trezzi, D; Vaccarone, R; Zavatarelli, S

    2013-01-01

    The AEgIS experiment is an international collaboration with the main goal of performing the fi rst direct measurement of the Earth ' s gravitational acceleration on antimatter. Critical to the success of AEgIS is the production of cold antihydrogen ( H) atoms. The FACT detector is used to measure the production and temperature of the H atoms and for establishing the formation of a H 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 production, operate at 4 K inside a 1 T solenoidal fi eld and not produce more than 10 W of heat. The FACT detector consists of two concentric cylindrical layers of 400 scintillator fi bres with a 1 mm diameter and a 0.6 mm pitch. The scintillating fi bres are coupled to clear fi bres which transport the scintillation light to 800 silicon photomultipliers. Each silicon photomultiplier signal is connected to a linear ampli fi er and a fast discriminator, the out...

  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. 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)

  12. Antimatter could fight cancer

    CERN Document Server

    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.

  13. 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.

  14. Developer Driven and User Driven Usability Evaluations

    DEFF Research Database (Denmark)

    Bruun, Anders

    2013-01-01

    Usability evaluation provide software development teams with insights on the degree to which a software application enables a user to achieve his/her goals, how fast these goals can be achieved, how easy it is to learn and how satisfactory it is in use Although usability evaluations are crucial....... The four primary findings from my studies are: 1) The developer driven approach reveals a high level of thoroughness and downstream utility. 2) The user driven approach has higher performance regarding validity 3) The level of reliability is comparable between the two approaches. 4) The user driven...

  15. Query Driven Visualization

    CERN Document Server

    Buddelmeijer, Hugo

    2011-01-01

    The request driven way of deriving data in Astro-WISE is extended to a query driven way of visualization. This allows scientists to focus on the science they want to perform, because all administration of their data is automated. This can be done over an abstraction layer that enhances control and flexibility for the scientist.

  16. Laser-Driven Fusion.

    Science.gov (United States)

    Gibson, A. F.

    1980-01-01

    Discusses the present status and future prospects of laser-driven fusion. Current research (which is classified under three main headings: laser-matter interaction processes, compression, and laser development) is also presented. (HM)

  17. 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...

  18. Can the matter-antimatter asymmetry be easier to understand within the "spin-charge-family-theory", predicting twice four families and two times $SU(2)$ vector gauge and scalar fields?

    CERN Document Server

    Borstnik, N S Mankoc

    2010-01-01

    This contribution is an attempt to try to understand the matter-antimatter asymmetry in the universe within the {\\it spin-charge-family-theory} if assuming that transitions in non equilibrium processes among instanton vacua and complex phases in mixing matrices are the sources of the matter-antimatter asymmetry, as studied in the literature for several proposed theories. The {\\it spin-charge-family-theory} is, namely, very promising in showing the right way beyond the {\\it standard model}. It predicts families and their mass matrices, explaining the origin of the charges and of the gauge fields. It predicts that there are, after the universe passes through two $SU(2)\\times U(1)$ phase transitions, in which the symmetry breaks from $SO(1,3) \\times SU(2) \\times SU(2) \\times U(1) \\times SU(3)$ first to $SO(1,3) \\times SU(2) \\times U(1) \\times SU(3)$ and then to $SO(1,3) \\times U(1) \\times SU(3)$, twice decoupled four families. The upper four families gain masses in the first phase transition, while the second fo...

  19. 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...

  20. 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.

  1. 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

  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. 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.

  4. Electrically driven optical antennas

    Science.gov (United States)

    Kern, Johannes; Kullock, René; Prangsma, Jord; Emmerling, Monika; Kamp, Martin; Hecht, Bert

    2015-09-01

    Unlike radiowave antennas, so far optical nanoantennas cannot be fed by electrical generators. Instead, they are driven by light or indirectly via excited discrete states in active materials in their vicinity. Here we demonstrate the direct electrical driving of an in-plane optical antenna by the broadband quantum-shot noise of electrons tunnelling across its feed gap. The spectrum of the emitted photons is determined by the antenna geometry and can be tuned via the applied voltage. Moreover, the direction and polarization of the light emission are controlled by the antenna resonance, which also improves the external quantum efficiency by up to two orders of magnitude. The one-material planar design offers facile integration of electrical and optical circuits and thus represents a new paradigm for interfacing electrons and photons at the nanometre scale, for example for on-chip wireless communication and highly configurable electrically driven subwavelength photon sources.

  5. 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.

  6. QED-driven laser absorption

    Science.gov (United States)

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

    2016-10-01

    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser (I >1018 W cm-2 where I is intensity at 1 μm wavelength) illuminates optically-thick matter. It underpins important applications of petawatt laser systems today, e.g., in isochoric heating of materials. Next-generation lasers such as ELI are anticipated to produce quantum electrodynamical (QED) bursts of γ-rays and anti-matter via the multiphoton Breit-Wheeler process which could enable scaled laboratory probes, e.g., of black hole winds. Here, applying strong-field QED to advances in plasma kinematic theory, we present a model elucidating absorption limited only by an avalanche of self-created electron-positron pairs at ultra-high-field. The model, confirmed by multidimensional QED-PIC simulations, works over six orders of magnitude in optical intensity and reveals this cascade is initiated at 1.8 x 1025 W cm-2 using a realistic linearly-polarized laser pulse. Here the laser couples its energy into highly-collimated electrons, ions, γ-rays, and positrons at 12%, 6%, 58% and 13% efficiency, respectively. We remark on attributes of the QED plasma state and possible applications.

  7. 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....

  8. Improved optically driven microrotors

    Science.gov (United States)

    Asavei, Theodor; Loke, Vincent L. Y.; Nieminen, Timo A.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina

    2008-08-01

    Two-photon polymerization of optically curing resins is a powerful method to fabricate micron sized objects which can be used as tools to measure properties at small scales. These microdevices can be driven by means of externally applied focused laser beams (optical tweezers) through angular momentum exchange, giving rise to a net torque. The advantage of the optical drive is that no contact is required, therefore making the microdevices suited to non-invasive biological applications. The fabrication method is versatile and allows building objects of any 3D shape. We discuss the design and modelling of various optically driven rotors. In particular, we consider fabrication of microspheres with an internal shape birefringence in order to obtain rotation in an optical trap. The reason for fabricating this type of object is that they are well-suited for studies of mechanical properties of single biomolecules such as the torsional stiffness of DNA or torque generated by molecular motors. The microspheres fabricated are able to transduce torques of 2000 pNnm with optical powers of 500 mW and could be rotated with frequencies up to 40 Hz in circularly polarized light.

  9. 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...

  10. 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.

  11. 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...

  12. Muscle-driven nanogenerators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhong L. (Marietta, GA); Yang, Rusen (Atlanta, GA)

    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.

  13. 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.

  14. Employee-driven innovation

    DEFF Research Database (Denmark)

    Kesting, Peter; Ulhøi, John Parm

    2015-01-01

    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...... 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...... 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...

  15. 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.

  16. Ischemia-driven angiogenesis.

    Science.gov (United States)

    Dor, Y; Keshet, E

    1997-11-01

    New blood vessels usually develop in places where they are most needed. A prime example of neovascularization representing a positive feedback response to insufficient perfusion is the development of collateral blood vessels in the ischemic myocardium and leg. The recent discoveries of hypoxia-inducible transcription and angiogenic factors have provided important mechanistic links between the metabolic consequences of ischemia and compensatory angiogenesis. Vascular endothelial growth factor (VEGF) has emerged as the key mediator of ischemia-driven angiogenesis. Environmental stresses, including hypoxia, hypoglycemia, and hypoferremia, upregulate VEGF expression at both the transcriptional and posttranscriptional levels. VEGF acts in turn on adjacent vascular beds expressing cognate receptors and induces sprouting and capillary growth toward the ischemic tissue. In addition to expanding the vasculature at sites where existing vessels have been occluded or obliterated, VEGF also functions to match the vascular density according to development and physiologic increases in oxygen consumption. Fine adjustment of the vasculature includes a step of oxygen-regulated vascular pruning mediated by VEGF in its capacity as a survival factor for newly formed vessels. Pathologic settings of ischemia-driven angiogenesis include a major component of stress-induced angiogenesis during tumor neovascularization and abnormal vessel growth associated with retinopathies. The latter represents an excessive angiogenic response to conditions of severe retinal ischemia. Further insights into the mechanism of stress-induced angiogenesis are likely to suggest new ways to augment growth of collateral vessels and to restrain unwarranted neovascularization in tumors and retinopathies. (Trends Cardiovasc Med 1997;7:289-294). © 1997, Elsevier Science Inc.

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. Syntactic-Head-Driven Generation

    CERN Document Server

    Koenig, E

    1994-01-01

    The previously proposed semantic-head-driven generation methods run into problems if none of the daughter constituents in the syntacto-semantic rule schemata of a grammar fits the definition of a semantic head given in Shieber et al. 1990. This is the case for the semantic analysis rules of certain constraint-based semantic representations, e.g. Underspecified Discourse Representation Structures (UDRSs) (Frank/Reyle 1992). Since head-driven generation in general has its merits, we simply return to a syntactic definition of `head' and demonstrate the feasibility of syntactic-head-driven generation. In addition to its generality, a syntactic-head-driven algorithm provides a basis for a logically well-defined treatment of the movement of (syntactic) heads, for which only ad-hoc solutions existed, so far.

  3. 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

  4. User Driven Innovation Construct Development

    Directory of Open Access Journals (Sweden)

    Tine Nagy

    2011-12-01

    Full Text Available In this paper by the literature review we interpreted changes in societyand other changing conditions that have contributed to the emergenceof user-driven innovation and a ‘design thinking’ approach. Thetwo areas are very similar in practice, so we suggest combining theminto a construct. The construct is a pioneer contribution to the developmentof science in the field of user-driven innovation and the designthinking approach.

  5. 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%.

  6. Magnetically driven quantum heat engine

    Science.gov (United States)

    Muñoz, Enrique; Peña, Francisco J.

    2014-05-01

    We studied the efficiency of two different schemes for a magnetically driven quantum heat engine, by considering as the "working substance" a single nonrelativistic particle trapped in a cylindrical potential well, in the presence of an external magnetic field. The first scheme is a cycle, composed of two adiabatic and two isoenergetic reversible trajectories in configuration space. The trajectories are driven by a quasistatic modulation of the external magnetic-field intensity. The second scheme is a variant of the former, where the isoenergetic trajectories are replaced by isothermal ones, along which the system is in contact with macroscopic thermostats. This second scheme constitutes a quantum analog of the classical Carnot cycle.

  7. Data-Driven Proficiency Profiling

    Science.gov (United States)

    Mostafavi, Behrooz; Liu, Zhongxiu; Barnes, Tiffany

    2015-01-01

    Deep Thought is a logic tutor where students practice constructing deductive logic proofs. Within Deep Thought is a data-driven mastery learning system (DDML), which calculates student proficiency based on rule scores weighted by expert-decided weights in order to assign problem sets of appropriate difficulty. In this study, we designed and tested…

  8. Light-driven molecular motors

    OpenAIRE

    van Delden, RA; FERINGA, BL; Kuzmany, H.; Fink, J.; Mehring, M.; Roth, S.

    2004-01-01

    Molecular motors can be defined as molecules that are able to convert any type of energy input (a fuel) into controlled motion. These systems can be categorized into linear and rotary motors, depending on the motion induced. This brief account will discuss the state of affairs of the research on light-driven rotary molecular motors.

  9. Synchrotron-driven spallation sources

    CERN Document Server

    Bryant, P J

    1996-01-01

    The use of synchrotrons for pulsed neutron spallation sources is an example of scientific and technological spin-off from the accelerator development for particle physics. Accelerator-driven sources provide an alternative to the continuous-flux, nuclear reactors that currently furnish the majority of neutrons for research and development. Although the present demand for neutrons can be adequately met by the existing reactors, this situation is unlikely to continue due to the increasing severity of safety regulations and the declared policies of many countries to close down their reactors within the next decade or so. Since the demand for neutrons as a research tool is, in any case,expected to grow, there has been a corresponding interest in sources that are synchrotron-driven or linac-driven with a pulse compression ring and currently several design studies are being made. These accelerator-driven sources also have the advantage of a time structure with a high peak neutron flux. The basic requirement is for a...

  10. 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.

  11. 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).

  12. 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...... the chasm between development and implementation through a sustained focus on the effects to be achieved by users through their adoption and use of a system. This involves iteratively (a) specifying the purpose of the system in terms of effects, (b) developing an IT system and associated organizational...... change that realize the specified effects, and (c) measuring the absence or presence of the specified effects during pilot use of the system while also remaining alert to the emergence of beneficial but hitherto unspecified effects. In this paper we explore effects-driven IT development and discuss...

  13. 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...

  14. Pulsed Power Driven Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)

    SLUTZ,STEPHEN A.

    1999-11-22

    Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

  15. 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

  16. Optimizing Event-Driven Simulations

    CERN Document Server

    De Michele, Cristiano

    2010-01-01

    Event-driven molecular dynamics is a valuable tool in condensed and soft matter physics when particles can be modeled as hard objects or more generally if their interaction potential can be modeled in a stepwise fashion. Hard spheres model has been indeed widely used both for computational and theoretical description of physical systems. Recently further developments of computational techniques allow simulations of hard rigid objects of generic shape. In present paper we will present some optimizations for event-driven simulations that offered significant speedup over previous methods. In particular we will describe a generalization of well known linked list method and an improvement on nearest neighbor lists method recently proposed by us.

  17. Electrically-driven optical antennas

    CERN Document Server

    Kern, Johannes; Prangsma, Jord C; Emmerling, Monika; Kamp, Martin; Hecht, Bert

    2015-01-01

    Unlike radiowave antennas, optical nanoantennas so far cannot be fed by electrical generators. Instead, they are driven by light or via optically active materials in their proximity. Here, we demonstrate direct electrical driving of an optical nanoantenna featuring an atomic-scale feed gap. Upon applying a voltage, quantum tunneling of electrons across the feed gap creates broadband quantum shot noise. Its optical frequency components are efficiently converted into photons by the antenna. We demonstrate that the properties of the emitted photons are fully controlled by the antenna architecture, and that the antenna improves the quantum efficiency by up to two orders of magnitude with respect to a non-resonant reference system. Our work represents a new paradigm for interfacing electrons and photons at the nanometer scale, e.g. for on-chip wireless data communication, electrically driven single- and multiphoton sources, as well as for background-free linear and nonlinear spectroscopy and sensing with nanometer...

  18. Driven optical matter (Conference Presentation)

    Science.gov (United States)

    Figliozzi, Patrick; Sule, Nishant; Yan, Zijie; Vaikuntanathan, Suriyanarayanan; Rice, Stuart A.; Scherer, Norbert F.

    2016-09-01

    Optical trapping has enabled studying a wide variety of questions and systems in chemistry, biology, physics, and materials science. For example, optical trapping has been used to understand hydrodynamic interactions in dilute and dense colloidal fluids and discover connections to granular materials. In this presentation we show that shaped optical fields and gradients can be used to study the electrodynamic interactions amongst nanoparticles (NPs) and drive them into new ordered states. We demonstrate the formation and use of NP-based optical matter to study a range of nonequilibrium phenomena in solution; field-driven barrier crossing phenomena and noise-driven ordering. Optical matter, a material that forms only in the presence of an optical field, involves NP interactions by optical scattering and interference. Metal NPs can be formed into regular arrangements in minimally shaped fields; e.g., in focused Gaussian beams, line traps, and optical ring traps. Inter-particle interactions and motions are also affected when the optical matter is driven. Particles recirculate in an optical ring vortex trap allowing long term measurements to examine rare events. In particular, particles can hop between optical binding sites, move past electrodynamic obstacles or pass each other while moving around the ring. The polarization state of the optical beam can be used to produce periodic variations of the NP electrodynamic interactions. As particles circulate this "noise" causes NP clusters to be less stable as if the temperature of the system is increased. Conversely, we observe noise-driven ordering in dense systems. We will explain these phenomena using simulations and theory.

  19. 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

  20. 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.

  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. Quantum Vacuum and a Matter - Antimatter Cosmology

    CERN Document Server

    Rothwarf, F; Rothwarf, Frederick; Roy, Sisir

    2007-01-01

    A model of the universe as proposed by Allen Rothwarf based upon a degenerate Fermion fluid composed of polarizable particle-antiparticle pairs leads to a big bang model of the universe where the velocity of light varies inversely with the square root of cosmological time, t. This model is here extended to predict a decelerating expansion of the universe and to derive the Tully-Fisher law describing the flat rotation curves of spiral galaxies. The estimated critical acceleration parameter, aoR, is compared to the experimental, critical modified Newtonian Dynamics (MOND) cosmological acceleration constant, obtained by fitting a large number of rotation curves. The present estimated value is much closer to the experimental value than that obtained with the other models. This model for aR(t) allows the derivation of the time dependent radius of the universe as a function of red shift Other cosmological parameters such as the velocity of light, Hubble's constant, the Tully-Fisher relation, and the index of refrac...

  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. 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

  5. Understand antimatter better #13TeV

    CERN Multimedia

    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

  6. 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

  7. Driven fragmentation of granular gases.

    Science.gov (United States)

    Cruz Hidalgo, Raúl; Pagonabarraga, Ignacio

    2008-06-01

    The dynamics of homogeneously heated granular gases which fragment due to particle collisions is analyzed. We introduce a kinetic model which accounts for correlations induced at the grain collisions and analyze both the kinetics and relevant distribution functions these systems develop. The work combines analytical and numerical studies based on direct simulation Monte Carlo calculations. A broad family of fragmentation probabilities is considered, and its implications for the system kinetics are discussed. We show that generically these driven materials evolve asymptotically into a dynamical scaling regime. If the fragmentation probability tends to a constant, the grain number diverges at a finite time, leading to a shattering singularity. If the fragmentation probability vanishes, then the number of grains grows monotonously as a power law. We consider different homogeneous thermostats and show that the kinetics of these systems depends weakly on both the grain inelasticity and driving. We observe that fragmentation plays a relevant role in the shape of the velocity distribution of the particles. When the fragmentation is driven by local stochastic events, the long velocity tail is essentially exponential independently of the heating frequency and the breaking rule. However, for a Lowe-Andersen thermostat, numerical evidence strongly supports the conjecture that the scaled velocity distribution follows a generalized exponential behavior f(c) approximately exp(-cn) , with n approximately 1.2 , regarding less the fragmentation mechanisms.

  8. 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

  9. Elasticity-Driven Backflow of Fluid-Driven Cracks

    Science.gov (United States)

    Lai, Ching-Yao; Zheng, Zhong; Dressaire, Emilie; Ramon, Guy; Huppert, Herbert E.; Stone, Howard A.

    2016-11-01

    Fluid-driven cracks are generated by the injection of pressurized fluid into an elastic medium. Once the injection pressure is released, the crack closes up due to elasticity and the fluid in the crack drains out of the crack through an outlet, which we refer to as backflow. We experimentally study the effects of crack size, elasticity of the matrix, and fluid viscosity on the backflow dynamics. During backflow, the volume of liquid remaining in the crack as a function of time exhibits a transition from a fast decay at early times to a power law behavior at late times. Our results at late times can be explained by scaling arguments balancing elastic and viscous stresses in the crack. This work may relate to the environmental issue of flowback in hydraulic fracturing. This work is supported by National Science Foundation via Grant CBET-1509347 and partially supported by Andlinger Center for Energy and the Environment at Princeton University.

  10. Evaluation of Respondent-Driven Sampling

    OpenAIRE

    McCreesh, N; Frost, SD; Seeley, J.; Katongole, J; Tarsh, MN; Ndunguse, R; Jichi, F; Lunel, NL; Maher, D.; Johnston, LG; Sonnenberg, P; Copas, AJ; Hayes, RJ; White, RG

    2012-01-01

    : BACKGROUND:: Respondent-driven sampling is a novel variant of link-tracing sampling for estimating the characteristics of hard-to-reach groups, such as HIV prevalence in sex workers. Despite its use by leading health organizations, the performance of this method in realistic situations is still largely unknown. We evaluated respondent-driven sampling by comparing estimates from a respondent-driven sampling survey with total population data. METHODS:: Total population data on age, tribe, rel...

  11. 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

  12. 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....

  13. Asynchronous Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-08-30

    We present, in a unifying way, the main components of three asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel stochastic molecular-dynamics algorithm that builds on the Direct Simulation Monte Carlo (DSMC). We explain how to effectively combine event-driven and classical time-driven handling, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  14. Asynchronous Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-02-28

    We present in a unifying way the main components of three examples of asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel event-driven algorithm for Direct Simulation Monte Carlo (DSMC). Finally, we describe how to combine MD with DSMC in an event-driven framework, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  15. Investigation of Current Driven Loudspeakers

    DEFF Research Database (Denmark)

    Schneider, Henrik; Agerkvist, Finn T.; Knott, Arnold

    2015-01-01

    Current driven loudspeakers have previously been investigated but the literature is limited and the advantages and disadvantages are yet to be fully identified. This paper makes use of a non-linear loudspeaker model to analyse loudspeakers with distinct non-linear characteristics under voltage...... and current drive. A multi tone test signal is used in the evaluation of the driving schemes since it resembles audio signals to a higher degree than the signals used in total harmonic distortion and intermodulation distortion test methods. It is found that current drive is superior over voltage drive in a 5......” woofer where a copper ring in the pole piece has not been implemented to compensate for eddy currents. However the drive method seems to be irrelevant for a 5” woofer where the compliance, force factor as well as the voice coil inductance has been optimized for linearity....

  16. 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...

  17. 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...... outline the 'grand structure' of the phenomenon in order to identify underlying processes as well as the most relevant drivers of EDI. Based on these insights we identify open research questions and make suggestions for the next steps. Our main argument is that 'ordinary' employees can specially...

  18. Wonder-driven Entrepreneurship Teaching

    DEFF Research Database (Denmark)

    Hansen, Finn Thorbjørn; Herholdt-Lomholdt, Sine Maria

    2015-01-01

    Contemporary research on creativity, innovation and entrepreneurship have now for a decade or more been focusing on social constructive, pragmatic, socio-cultural and socio-material dimensions of creative and innovative processes and entrepreneurship (Bager et al. 2010, Brinkmann & Tangaard 2010......- and entrepreneurship processes. In this paper we want to continue in line with this new framework of meaning- and wonder-driven innovation by focusing on the possible educational consequences of such an approach. Our empirical departure is our three-year phenomenological action research project called ‘Wonder......-based Entrepreneurship Teaching in Professional bachelor Education’. Ten senior lecturers in nursing and pedagogy participated. The purpose was to investigate whether and how Socratic and philosophical dialogues and different forms of phenomenological and existential reflections upon one´s own professional assumptions...

  19. 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.

  20. 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...

  1. 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 sim...

  2. Motor-Driven Giant Magnetostrictive Actuator

    DEFF Research Database (Denmark)

    Zhang, Lihui; Xia, Yongming; Lu, Kaiyuan

    2015-01-01

    to produce the desired magnetic field when an output strain should be maintained. The GMA does not produce any mechanical power in this condition, but constant power is being consumed by the excitation coil. This paper presents a new type of motor-driven GMA (MDGMA), which works in a coil-free driven manner...

  3. Gravity-Driven Hydraulic Fractures

    Science.gov (United States)

    Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.

    2014-12-01

    This study is motived by a new method for disposing of nuclear waste by injecting it as a dense slurry into a hydraulic fracture that grows downward to great enough depth to permanently isolate the waste. Disposing of nuclear waste using gravity-driven hydraulic fractures is mechanically similar to the upward growth of dikes filled with low density magma. A fundamental question in both applications is how the injected fluid controls the propagation dynamics and fracture geometry (depth and breadth) in three dimensions. Analog experiments in gelatin [e.g., Heimpel and Olson, 1994; Taisne and Tait, 2009] show that fracture breadth (the short horizontal dimension) remains nearly stationary when the process in the fracture "head" (where breadth is controlled) is dominated by solid toughness, whereas viscous fluid dissipation is dominant in the fracture tail. We model propagation of the resulting gravity-driven (buoyant or sinking), finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response to fluid loading in a horizontal cross-section is local and can be treated similar to the classical Perkins-Kern-Nordgren (PKN) model of hydraulic fracturing. The propagation condition for a finger-like crack is based on balancing the global energy release rate due to a unit crack extension with the rock fracture toughness. It allows us to relate the net fluid pressure at the tip to the fracture breadth and rock toughness. Unlike the PKN fracture, where breadth is known a priori, the final breadth of a finger-like fracture is a result of processes in the fracture head. Because the head is much more open than the tail, viscous pressure drop in the head can be neglected leading to a 3D analog of Weertman's hydrostatic pulse. This requires relaxing the local elasticity assumption of the PKN model in the fracture head. As a result, we resolve the breadth, and then match the viscosity-dominated tail with the 3-D, toughness

  4. Driven tracers in narrow channels

    Science.gov (United States)

    Cividini, J.; Mukamel, D.; Posch, H. A.

    2017-01-01

    Steady-state properties of a driven tracer moving in a narrow two-dimensional (2D) channel of quiescent medium are studied. The tracer drives the system out of equilibrium, perturbs the density and pressure fields, and gives the bath particles a nonzero average velocity, creating a current in the channel. Three models in which the confining effect of the channel is probed are analyzed and compared in this study: the first is the simple symmetric exclusion process (SSEP), for which the stationary density profile and the pressure on the walls in the frame of the tracer are computed. We show that the tracer acts like a dipolar source in an average velocity field. The spatial structure of this 2D strip is then simplified to a one-dimensional (1D) SSEP, in which exchanges of position between the tracer and the bath particles are allowed. Using a combination of mean-field theory and exact solution in the limit where no exchange is allowed gives good predictions of the velocity of the tracer and the density field. Finally, we show that results obtained for the 1D SSEP with exchanges also apply to a gas of overdamped hard disks in a narrow channel. The correspondence between the parameters of the SSEP and of the gas of hard disks is systematic and follows from simple intuitive arguments. Our analytical results are checked numerically.

  5. 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...

  6. Metrics for Event Driven Software

    Directory of Open Access Journals (Sweden)

    Neha Chaudhary

    2016-01-01

    Full Text Available The evaluation of Graphical User Interface has significant role to improve its quality. Very few metrics exists for the evaluation of Graphical User Interface. The purpose of metrics is to obtain better measurements in terms of risk management, reliability forecast, project scheduling, and cost repression. In this paper structural complexity metrics is proposed for the evaluation of Graphical User Interface. Structural complexity of Graphical User Interface is considered as an indicator of complexity. The goal of identifying structural complexity is to measure the GUI testability. In this testability evaluation the process of measuring the complexity of the user interface from testing perspective is proposed. For the GUI evaluation and calculating structural complexity an assessment process is designed which is based on types of events. A fuzzy model is developed to evaluate the structural complexity of GUI. This model takes five types of events as input and return structural complexity of GUI as output. Further a relationship is established between structural complexity and testability of event driven software. Proposed model is evaluated with four different applications. It is evident from the results that higher the complexities lower the testability of application.

  7. Cosmic ray driven Galactic winds

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2016-11-01

    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 Alfvén waves, that in turn determines 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 implications for the spectrum of cosmic rays by solving together the hydrodynamical equations for the wind and the transport equation for cosmic rays under the action of self-generated diffusion and advection with the wind and the self-excited Alfvén waves.

  8. Bubble-Driven Inertial Micropump

    CERN Document Server

    Torniainen, Erik D; Markel, David P; Kornilovitch, Pavel E

    2012-01-01

    The fundamental action of the bubble-driven inertial micropump is investigated. The pump has no moving parts and consists of a thermal resistor placed asymmetrically within a straight channel connecting two reservoirs. Using numerical simulations, the net flow is studied as a function of channel geometry, resistor location, vapor bubble strength, fluid viscosity, and surface tension. Two major regimes of behavior are identified: axial and non-axial. In the axial regime, the drive bubble either remains inside the channel or continues to grow axially when it reaches the reservoir. In the non-axial regime the bubble grows out of the channel and in all three dimensions while inside the reservoir. The net flow in the axial regime is parabolic with respect to the hydraulic diameter of the channel cross-section but in the non-axial regime it is not. From numerical modeling, it is determined that the net flow is maximal when the axial regime crosses over to the non-axial regime. To elucidate the basic physical princi...

  9. 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.

  10. 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

  11. Disentangling Competition Among Platform Driven Strategic Groups

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...

  12. Quasi-Periodically Driven Quantum Systems

    Science.gov (United States)

    Verdeny, Albert; Puig, Joaquim; Mintert, Florian

    2016-10-01

    Floquet theory provides rigorous foundations for the theory of periodically driven quantum systems. In the case of non-periodic driving, however, the situation is not so well understood. Here, we provide a critical review of the theoretical framework developed for quasi-periodically driven quantum systems. Although the theoretical footing is still under development, we argue that quasi-periodically driven quantum systems can be treated with generalisations of Floquet theory in suitable parameter regimes. Moreover, we provide a generalisation of the Floquet-Magnus expansion and argue that quasi-periodic driving offers a promising route for quantum simulations.

  13. 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

  14. 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.

  15. 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.

  16. Molecular dynamics for irradiation driven chemistry

    DEFF Research Database (Denmark)

    Sushko, Gennady B.; Solov'yov, Ilia A.; Solov'yov, Andrey V.

    2016-01-01

    that describe the classical MD of complex molecular systems under irradiation. The proposed irradiation driven molecular dynamics (IDMD) methodology is designed for the molecular level description of the irradiation driven chemistry. The IDMD approach is implemented into the MBN Explorer software package...... capable to operate with a large library of classical potentials, many-body force fields and their combinations. IDMD opens a broad range of possibilities for modelling of irradiation driven modifications and chemistry of complex molecular systems ranging from radiotherapy cancer treatments to the modern...... technologies such as focused electron beam deposition (FEBID). As an example, the new methodology is applied for studying the irradiation driven chemistry caused by FEBID of tungsten hexacarbonyl W(CO)6 precursor molecules on a hydroxylated SiO2 surface. It is demonstrated that knowing the interaction...

  17. Quality Attribute Driven Software Architecture Reconstruction

    Science.gov (United States)

    2016-06-21

    3890 Quality Attribute Driven Software Architecture Reconstruction SATURN Workshop April 7, 2005 Liam O’Brien © 2005 by Carnegie Mellon University...Version 1.0 QADSAR – SATURN 2005 - page 2 Motivation - 1 • Software architectures are critical to implement an organization’s business goals and critical...Attribute Driven Software Architecture Reconstruction 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

  18. Radiative Interaction Between Driver and Driven Gases in an Arc-Driven Shock Tube

    Science.gov (United States)

    Bogdanoff, David W.; Park, Chul

    2001-01-01

    An electric-arc driven shock tube was operated with hydrogen as the driven gas and either hydrogen or helium as the driver gas. Electron density was measured behind the primary shock wave spectroscopically from the width of the Beta line of hydrogen. The measured electron density values were many times greater than the values calculated by the Rankine - Hugoniot relations. By accounting for the radiative transfer from the driver gas to the driven gas, the measured electron density values were numerically recreated.

  19. 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...

  20. 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.

  1. Simple driven chaotic oscillators with complex variables.

    Science.gov (United States)

    Marshall, Delmar; Sprott, J C

    2009-03-01

    Despite a search, no chaotic driven complex-variable oscillators of the form z+f(z)=e(iOmegat) or z+f(z)=e(iOmegat) are found, where f is a polynomial with real coefficients. It is shown that, for analytic functions f(z), driven complex-variable oscillators of the form z+f(z)=e(iOmegat) cannot have chaotic solutions. Seven simple driven chaotic oscillators of the form z+f(z,z)=e(iOmegat) with polynomial f(z,z) are given. Their chaotic attractors are displayed, and Lyapunov spectra are calculated. Attractors for two of the cases have symmetry across the x=-y line. The systems' behavior with Omega as a control parameter in the range of Omega=0.1-2.0 is examined, revealing cases of period doubling, intermittency, chaotic transients, and period adding as routes to chaos. Numerous cases of coexisting attractors are also observed.

  2. 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 ...

  3. 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.

  4. Advances in Electrically Driven Thermal Management

    Science.gov (United States)

    Didion, Jeffrey R.

    2017-01-01

    Electrically Driven Thermal Management is a vibrant technology development initiative incorporating ISS based technology demonstrations, development of innovative fluid management techniques and fundamental research efforts. The program emphasizes high temperature high heat flux thermal management required for future generations of RF electronics and power electronic devices. This presentation reviews i.) preliminary results from the Electrohydrodynamic (EHD) Long Term Flight Demonstration launched on STP-H5 payload in February 2017 ii.) advances in liquid phase flow distribution control iii.) development of the Electrically Driven Liquid Film Boiling Experiment under the NASA Microgravity Fluid Physics Program.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Limited resources in a driven diffusion process.

    Science.gov (United States)

    Brackley, Chris A; Romano, M Carmen; Grebogi, Celso; Thiel, Marco

    2010-08-13

    The advance of particles in many driven diffusion systems depends on the availability of resources in the surrounding environment. In the balance between supply and demand of such resources we are confronted with a regime in which, under limited resource availability, the flow is markedly reduced. In the context of mRNA translation this represents the finite availability of amino acid-tRNA molecules. In this limited resources regime a severe depletion of amino acid tRNAs is also observed. These dramatic effects are vital to our understanding of translation, and are likely to also be important for the many other applications of driven diffusion models.

  10. 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...

  11. Static Checking of Interrupt-driven Software

    DEFF Research Database (Denmark)

    Brylow, Dennis; Damgaard, Niels; Palsberg, Jens

    2001-01-01

    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...

  12. 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

  13. Osmosis is not driven by water dilution.

    Science.gov (United States)

    Kramer, Eric M; Myers, David R

    2013-04-01

    There is a misconception among plant scientists that osmosis is driven by the tendency of solutes to dilute water. In this opinion article, we discuss the quantitative and qualitative failures of this view, and go on to review the correct kinetic picture of osmosis as it appears in physics textbooks.

  14. Topology optimization of inertia driven dosing units

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe

    2016-01-01

    This paper presents a methodology for optimizing inertia driven dosing units, sometimes referred to as eductors, for use in small scale flow applications. The unit is assumed to operate at low to moderate Reynolds numbers and under steady state conditions. By applying topology optimization...

  15. Noise Control in Propeller-Driven Aircraft

    Science.gov (United States)

    Rennison, D. C.; Wilby, J. F.

    1983-01-01

    Analytical model predicts noise levels inside propeller-driven aircraft during cruise at mach 0.8. Double wall sidewalls minimize interior noise and weight. Model applied to three aircraft with fuselages of different size (wide-body, narrow-body, and small-diameter) to determine noise reductions required to achieve A-weighted sound level not to exceed 80 dB.

  16. 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....

  17. 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...

  18. 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...

  19. 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...

  20. 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

  1. Adaptive Output Tracking of Driven Oscillators

    Directory of Open Access Journals (Sweden)

    Lili Diao

    2008-01-01

    of the output tracking error to an adjustable neighborhood of the origin. In addition, good approximation of the unknown nonlinearities is also achieved by incorporating a persistent exciting signal in the parameter update law. The effectiveness of the proposed method is demonstrated by an application to a cardiac conduction system modelled by two coupled driven oscillators.

  2. 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.

  3. 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

  4. 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.

  5. 3D weighting in cone beam image reconstruction algorithms: ray-driven vs. pixel-driven.

    Science.gov (United States)

    Tang, Xiangyang; Nilsen, Roy A; Smolin, Alex; Lifland, Ilya; Samsonov, Dmitry; Taha, Basel

    2008-01-01

    A 3D weighting scheme have been proposed previously to reconstruct images at both helical and axial scans in stat-of-the-art volumetric CT scanners for diagnostic imaging. Such a 3D weighting can be implemented in the manner of either ray-driven or pixel-drive, depending on the available computation resources. An experimental study is conducted in this paper to evaluate the difference between the ray-driven and pixel-driven implementations of the 3D weighting from the perspective of image quality, while their computational complexity is analyzed theoretically. Computer simulated data and several phantoms, such as the helical body phantom and humanoid chest phantom, are employed in the experimental study, showing that both the ray-driven and pixel-driven 3D weighting provides superior image quality for diagnostic imaging in clinical applications. With the availability of image reconstruction engine at increasing computational power, it is believed that the pixel-driven 3D weighting will be dominantly employed in state-of-the-art volumetric CT scanners over clinical applications.

  6. 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...... of the ℓ1-norm on the constraint while still allowing for the application of kernels. We specialize the proposed constraint to orthogonality of the vectors between paired observations and the estimated hyperplane. We show that imposing the constraint of orthogonality on the paired data yields a more robust...

  7. Odd-frequency Superconductivity in Driven Systems

    Science.gov (United States)

    Triola, Christopher; Balatsky, Alexander

    We show that Berezinskii's classification of the symmetries of Cooper pair amplitudes in terms of parity under transformations that invert spin, space, time, and orbital degrees of freedom holds for driven systems even in the absence of translation invariance. We then discuss the conditions under which pair amplitudes which are odd in frequency can emerge in driven systems. Considering a model Hamiltonian for a superconductor coupled to an external driving potential, we investigate the influence of the drive on the anomalous Green's function, density of states, and spectral function. We find that the anomalous Green's function develops odd in frequency component in the presence of an external drive. Furthermore we investigate how these odd-frequency terms are related to satellite features in the density of states and spectral function. Supported by US DOE BES E 304.

  8. Image Filtering Driven by Level Curves

    Science.gov (United States)

    Rajwade, Ajit; Banerjee, Arunava; Rangarajan, Anand

    This paper presents an approach to image filtering that is driven by the properties of the iso-valued level curves of the image and their relationship with one another. We explore the relationship of our algorithm to existing probabilistically driven filtering methods such as those based on kernel density estimation, local-mode finding and mean-shift. Extensive experimental results on filtering gray-scale images, color images, gray-scale video and chromaticity fields are presented. In contrast to existing probabilistic methods, in our approach, the selection of the parameter that prevents diffusion across the edge is robustly decoupled from the smoothing of the density itself. Furthermore, our method is observed to produce better filtering results for the same settings of parameters for the filter window size and the edge definition.

  9. Ontology Driven Piecemeal Development of Smart Spaces

    Science.gov (United States)

    Ovaska, Eila

    Software development is facing new challenges due to transformation from product based software engineering towards integration and collaboration based software engineering that embodies high degree of dynamism both at design time and run time. Short time-to-markets require cost reduction by maximizing software reuse; openness for new innovations presumes a flexible innovation platform and agile software development; and user satisfaction assumes high quality in a situation based manner. How to deal with these contradictory requirements in software engineering? The main contribution of this paper is a novel approach that is influenced by business innovation, human centered design, model driven development and ontology oriented design. The approach is called Ontology driven Piecemeal Software Engineering (OPSE). OPSE facilitates incremental software development based on software pieces that follow the design principles defined by means of ontologies. Its key elements are abstraction, aggregation and adaptivity. The approach is intended for and applied to the development of smart spaces.

  10. Mastering Technologies in Design-Driven Innovation

    DEFF Research Database (Denmark)

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

    2010-01-01

    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......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 the importance of supply networks that allow manufacturers to change product technologies quickly and experiment with new technologies....

  11. 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...

  12. 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 approximat......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....

  13. Employee Driven Innovation in Team (EDIT)

    DEFF Research Database (Denmark)

    Kristiansen, Marianne; Bloch-Poulsen, Jørgen

    2010-01-01

    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...... through strengthening dialogue in team based organizations" funded by the Danish Ministry of Science, Technology and Innovation. 18 teams from one public and two private organizations participated in the project. The article defines the concept of employee driven innovation (EDI) in relation to theories...... 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...

  14. 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.

  15. Position Control of Tendon-Driven Fingers

    Science.gov (United States)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Hargrave, B.; Pementer, Frank

    2011-01-01

    Conventionally, tendon-driven manipulators implement some force control scheme based on tension feedback. This feedback allows the system to ensure that the tendons are maintained taut with proper levels of tensioning at all times. Occasionally, whether it is due to the lack of tension feedback or the inability to implement sufficiently high stiffnesses, a position control scheme is needed. This work compares three position controllers for tendon-driven manipulators. A new controller is introduced that achieves the best overall performance with regards to speed, accuracy, and transient behavior. To compensate for the lack of tension feedback, the controller nominally maintains the internal tension on the tendons by implementing a two-tier architecture with a range-space constraint. These control laws are validated experimentally on the Robonaut-2 humanoid hand. I

  16. 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.

  17. User Driven Innovation in the Building Process

    DEFF Research Database (Denmark)

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

    2008-01-01

    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 Innovation......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...... 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....

  18. 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.

  19. 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...... detection and pushing error detection to earlier stages of development. The complexity of modeling and the size of systems which can be analyzed is severely limited when introducing data variables. The state space grows exponentially in the number of variable and the domain size of the variables...... 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...

  20. Surface chemistry driven actuation in nanoporous gold

    Energy Technology Data Exchange (ETDEWEB)

    Biener, J; Wittstock, A; Zepeda-Ruiz, L; Biener, M M; Zielasek, V; Kramer, D; Viswanath, R N; Weissmuller, J; Baumer, M; Hamza, A V

    2008-04-14

    Although actuation in biological systems is exclusively powered by chemical energy, this concept has not been realized in man-made actuator technologies, as these rely on generating heat or electricity first. Here, we demonstrate that surface-chemistry driven actuation can be realized in high surface area materials such as nanoporous gold. For example, we achieve reversible strain amplitudes in the order of a few tenths of a percent by alternating exposure of nanoporous Au to ozone and carbon monoxide. The effect can be explained by adsorbate-induced changes of the surface stress, and can be used to convert chemical energy directly into a mechanical response thus opening the door to surface-chemistry driven actuator and sensor technologies.

  1. 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...... 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......, 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...

  2. 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......-site processes. On the other hand generic technologies are also widely implemented in routine and day-today activities, making mobile technologies in construction a mix of user and technology driven innovations....

  3. Reverse Logistics and Market-Driven Management

    OpenAIRE

    Gandolfo, Alessandro; Sbrana, Roberto

    2008-01-01

    The reverse logistics applies to the flow of products and materials in the opposite direction to direct logistics, from the market to the production sites or the specialised centres, where they are sent to be appropriately treated. The growing attention to reverse logistics is explained primarily by the need to comply with regulations on environmental protection, Given the intensified competition caused by rising costs of energy and raw materials, the truly market-driven companies cannot cons...

  4. 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

  5. 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.

  6. 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)

  7. 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.

  8. Dynamic signatures of driven vortex motion.

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, G. W.; Kwok, W. K.; Lopez, D.; Olsson, R. J.; Paulius, L. M.; Petrean, A. M.; Safar, H.

    1999-09-16

    We probe the dynamic nature of driven vortex motion in superconductors with a new type of transport experiment. An inhomogeneous Lorentz driving force is applied to the sample, inducing vortex velocity gradients that distinguish the hydrodynamic motion of the vortex liquid from the elastic and-plastic motion of the vortex solid. We observe elastic depinning of the vortex lattice at the critical current, and shear induced plastic slip of the lattice at high Lorentz force gradients.

  9. Digitally Driven Antenna for HF Transmission

    Science.gov (United States)

    2010-09-01

    the 1-MHz carrier signal. This signal is then fed into the base terminals of an NPN /PNP transistor pair arranged in a push–pull configura- tion. A dual...voltage power supply, V, is con- nected to the system with the positive voltage connected to the collector terminal of the NPN transistor and the...complementary pair of switching transistors is driven with a pulsewidth modulated HF signal, eliminating the requirement for a frequency-dependent

  10. 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.

  11. The mechanics of gravity-driven faulting

    OpenAIRE

    L. Barrows; V. Barrows

    2010-01-01

    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 reb...

  12. Peltier effect in strongly driven quantum wires

    OpenAIRE

    Mierzejewski, M.; Crivelli, D.; Prelovsek, P.

    2013-01-01

    We study a microscopic model of a thermocouple device with two connected correlated quantum wires driven by a constant electric field. In such isolated system we follow the time-- and position--dependence of the entropy density using the concept of the reduced density matrix. At weak driving, the initial changes of the entropy at the junctions can be described by the linear Peltier response. At longer times the quasiequilibrium situation is reached with well defined local temperatures which i...

  13. 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.

  14. Malware Task Identification: A Data Driven Approach

    OpenAIRE

    Nunes, Eric; Buto, Casey; Shakarian, Paulo; Lebiere, Christian; Bennati, Stefano; THOMSON, ROBERT; Jaenisch, Holger

    2015-01-01

    Identifying the tasks a given piece of malware was designed to perform (e.g. logging keystrokes, recording video, establishing remote access, etc.) is a difficult and time-consuming operation that is largely human-driven in practice. In this paper, we present an automated method to identify malware tasks. Using two different malware collections, we explore various circumstances for each - including cases where the training data differs significantly from test; where the malware being evaluate...

  15. Ontology-driven health information systems architectures.

    Science.gov (United States)

    Blobel, Bernd; Oemig, Frank

    2009-01-01

    Following an architecture vision such as the Generic Component Model (GCM) architecture framework, health information systems for supporting personalized care have to be based on a component-oriented architecture. Representing concepts and their interrelations, the GCM perspectives system architecture, domains, and development process can be described by the domains' ontologies. The paper introduces ontology principles, ontology references to the GCM as well as some practical aspects of ontology-driven approaches to semantically interoperable and sustainable health information systems.

  16. Chaos control of parametric driven Duffing oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Leisheng; Mei, Jie; Li, Lijie, E-mail: L.Li@swansea.ac.uk [College of Engineering, Swansea University, Swansea SA2 8PP (United Kingdom)

    2014-03-31

    Duffing resonators are typical dynamic systems, which can exhibit chaotic oscillations, subject to certain driving conditions. Chaotic oscillations of resonating systems with negative and positive spring constants are identified to investigate in this paper. Parametric driver imposed on these two systems affects nonlinear behaviours, which has been theoretically analyzed with regard to variation of driving parameters (frequency, amplitude). Systematic calculations have been performed for these two systems driven by parametric pumps to unveil the controllability of chaos.

  17. Chaos control of parametric driven Duffing oscillators

    Science.gov (United States)

    Jin, Leisheng; Mei, Jie; Li, Lijie

    2014-03-01

    Duffing resonators are typical dynamic systems, which can exhibit chaotic oscillations, subject to certain driving conditions. Chaotic oscillations of resonating systems with negative and positive spring constants are identified to investigate in this paper. Parametric driver imposed on these two systems affects nonlinear behaviours, which has been theoretically analyzed with regard to variation of driving parameters (frequency, amplitude). Systematic calculations have been performed for these two systems driven by parametric pumps to unveil the controllability of chaos.

  18. Fluctuation relations for a driven Brownian particle

    Science.gov (United States)

    Imparato, A.; Peliti, L.

    2006-08-01

    We consider a driven Brownian particle, subject to both conservative and nonconservative applied forces, whose probability evolves according to the Kramers equation. We derive a general fluctuation relation, expressing the ratio of the probability of a given Brownian path in phase space with that of the time-reversed path, in terms of the entropy flux to the heat reservoir. This fluctuation relation implies those of Seifert, Jarzynski, and Gallavotti-Cohen in different special cases.

  19. Electrically Driven Liquid Film Boiling Experiment

    Science.gov (United States)

    Didion, Jeffrey R.

    2016-01-01

    This presentation presents the science background and ground based results that form the basis of the Electrically Driven Liquid Film Boiling Experiment. This is an ISS experiment that is manifested for 2021. Objective: Characterize the effects of gravity on the interaction of electric and flow fields in the presence of phase change specifically pertaining to: a) The effects of microgravity on the electrically generated two-phase flow. b) The effects of microgravity on electrically driven liquid film boiling (includes extreme heat fluxes). Electro-wetting of the boiling section will repel the bubbles away from the heated surface in microgravity environment. Relevance/Impact: Provides phenomenological foundation for the development of electric field based two-phase thermal management systems leveraging EHD, permitting optimization of heat transfer surface area to volume ratios as well as achievement of high heat transfer coefficients thus resulting in system mass and volume savings. EHD replaces buoyancy or flow driven bubble removal from heated surface. Development Approach: Conduct preliminary experiments in low gravity and ground-based facilities to refine technique and obtain preliminary data for model development. ISS environment required to characterize electro-wetting effect on nucleate boiling and CHF in the absence of gravity. Will operate in the FIR - designed for autonomous operation.

  20. 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.

  1. Exploring Titan with Autonomous, Buoyancy Driven Gliders

    Science.gov (United States)

    Morrow, M. T.; Woolsey, C. A.; Hagerman, G. M.

    Buoyancy driven underwater gliders are highly efficient winged underwater vehicles which locomote by modifying their internal shape. The concept, which is already well-proven in Earth's oceans, is also an appealing technology for remote terrain exploration and environmental sampling on worlds with dense atmospheres. Because of their high efficiency and their gentle, vertical take-off and landing capability, buoyancy driven gliders might perform long duration, global mapping tasks as well as light-duty, local sampling tasks. Moreover, a sufficiently strong gradient in the planetary boundary layer may enable the vehicles to perform dynamic soaring, achieving even greater locomotive efficiency. Shape Change Actuated, Low Altitude Robotic Soarers (SCALARS) are an appealing alternative to more conventional vehicle technology for exploring planets with dense atmospheres. SCALARS are buoyancy driven atmospheric gliders with a twin-hulled, inboard wing configuration. The inboard wing generates lift, which propels the vehicle forward. Symmetric changes in mass distribution induce gravitational pitch moments that provide longitudinal control. Asymmetric changes in mass distribution induce twist in the inboard wing that provides directional control. The vehicle is actuated solely by internal shape change; there are no external seals and no exposed moving parts, save for the inflatable buoyancy ballonets. Preliminary sizing analysis and dynamic modeling indicate the viability of using SCALARS to map the surface of Titan and to investigate features of interest.

  2. Dissipative adaptation in driven self-assembly.

    Science.gov (United States)

    England, Jeremy L

    2015-11-01

    In a collection of assembling particles that is allowed to reach thermal equilibrium, the energy of a given microscopic arrangement and the probability of observing the system in that arrangement obey a simple exponential relationship known as the Boltzmann distribution. Once the same thermally fluctuating particles are driven away from equilibrium by forces that do work on the system over time, however, it becomes significantly more challenging to relate the likelihood of a given outcome to familiar thermodynamic quantities. Nonetheless, it has long been appreciated that developing a sound and general understanding of the thermodynamics of such non-equilibrium scenarios could ultimately enable us to control and imitate the marvellous successes that living things achieve in driven self-assembly. Here, I suggest that such a theoretical understanding may at last be emerging, and trace its development from historic first steps to more recent discoveries. Focusing on these newer results, I propose that they imply a general thermodynamic mechanism for self-organization via dissipation of absorbed work that may be applicable in a broad class of driven many-body systems.

  3. 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.

  4. Pressure-driven instabilities in astrophysical jets

    CERN Document Server

    Longaretti, Pierre-Yves

    2008-01-01

    Astrophysical jets are widely believed to be self-collimated by the hoop-stress due to the azimuthal component of their magnetic field. However this implies that the magnetic field is largely dominated by its azimuthal component in the outer jet region. In the fusion context, it is well-known that such configurations are highly unstable in static columns, leading to plasma disruption. It has long been pointed out that a similar outcome may follow for MHD jets, and the reasons preventing disruption are still not elucidated, although some progress has been accomplished in the recent years. In these notes, I review the present status of this open problem for pressure-driven instabilities, one of the two major sources of ideal MHD instability in static columns (the other one being current-driven instabilities). I first discuss in a heuristic way the origin of these instabilities. Magnetic resonances and magnetic shear are introduced, and their role in pressure-driven instabilities discussed in relation to Suydam'...

  5. Strategic Planning and Market-Driven Management for Career Centers.

    Science.gov (United States)

    Chonko, Lawrence B.; Burley, Elizabeth

    1992-01-01

    Asserts that, when university career center pursues a strategic plan and becomes market driven, it is not only perceived to be a quality organization, it is one. Explains philosophy of market-driven management, marketing concept, and implementation of market-driven career planning and placement center. (NB)

  6. Comparison of Waste Heat Driven and Electrically Driven Cooling Systems for a High Ambient Temperature, Off-Grid Application

    Science.gov (United States)

    2012-12-10

    pumps, and oil -free screw and lobe type compressors . However, given the capacity of the AS, the low flow rates coupled with the low density made it...D R IV EN C O O LI N G COMPARISON OF WASTE HEAT DRIVEN AND ELECTRICALLY DRIVEN COOLING SYSTEMS FOR A HIGH AMBIENT TEMPERATURE, OFF- GRID...2010 to 10-12-2012 4. TITLE AND SUBTITLE COMPARISON OF WASTE HEAT DRIVEN AND ELECTRICALLY DRIVEN COOLING SYSTEMS FOR A HIGH AMBIENT TEMPERATURE

  7. 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.

  8. 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

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. Evidence for Magnetically Driven Protoplanetary Disk Winds

    Science.gov (United States)

    Simon, Molly; Pascucci, Ilaria; Edwards, Suzan; Feng, Wanda; Rigliaco, Elisabetta; Gorti, Uma; Hollenbach, David J.; Tuttle Keane, James

    2017-01-01

    We present Keck high resolution (~7km/s) optical spectra from a sample of 32 pre-main sequence T-Tauri stars in Taurus-Auriga plus TW Hya. We focus on low-excitation forbidden emission lines like the [O I] 6300 Å and 5577 Å lines, whose high-velocity component, with blueshifts between ~30 - 150 km/s, is known to trace fast outflowing material in the form of jets (e.g. Hartigan et al. 1995). The origin of the low-velocity component (LVC), with blueshifts on the order of ~5 km/s, has been long debated. We demonstrate that the LVC can be described by a combination of a broad and a narrow line emitting region. We show that the broad line emitting region is very common, arises within ~0.5 AU from the star, and shows the expected disk wind signature, i.e. larger blueshifts associated with narrower lines and lower disc inclinations. Such winds must be magnetically driven given that the emitting region is well inside the gravitational potential well of the central star. The origin of the narrow line emitting region remains difficult to assess, in particular we cannot exclude that it traces a thermally driven (photoevaporative) wind. Disk winds, both thermally and magnetically driven, might play a major role in the evolution and eventual dispersal of protoplanetary material, which has implications for solar system architectures and planet formation more generally. Hence, it is critical to determine the rate at which mass is lost via disk winds.

  14. 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.

  15. Instability in electromagnetically driven flows Part II

    OpenAIRE

    Imazio, Paola Rodriguez; Gissinger, Christophe

    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 flui...

  16. Early Work on Defect Driven Phase Transitions

    Science.gov (United States)

    Kosterlitz, J. Michael; Thouless, David J.

    2016-12-01

    This article summarizes the early history of the theory of phase transitions driven by topological defects, such as vortices in superfluid helium films or dislocations and disclinations in two-dimensional solids. We start with a review of our two earliest papers, pointing out their errors and omissions as well as their insights. We then describe the work, partly done by Kosterlitz but mostly done by other people, which corrected these oversights, and applied these ideas to experimental systems, and to numerical and experimental simulations.

  17. Manually operated piston-driven shock tube

    OpenAIRE

    Reddy, KPJ; Sharath, N

    2013-01-01

    A simple hand-operated shock tube capable of producing Mach 2 shock waves is described. Performance of this miniature shock tube using compressed high pressure air created by a manually operated piston in the driver section of the shock tube as driver gas with air at 1 atm pressure as the test gas in the driven tube is presented. The performance of the shock tube is found to match well with the theoretically estimated values using normal shock relations. Applications of this shock tube named ...

  18. 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.

  19. 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.

  20. Combining engineering and data-driven approaches

    DEFF Research Database (Denmark)

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

    2015-01-01

    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....... A framework is developed that is able to deal with data collection in non-homogeneous portfolios of buildings. Also incomplete data sets containing only little information on each fire event can be used for model calibration. To illustrate the capabilities of the proposed framework, it is applied...

  1. Optimality of Contraction-Driven Crawling

    Science.gov (United States)

    Recho, P.; Joanny, J.-F.; Truskinovsky, L.

    2014-05-01

    We study a particular mechanism of cell motility allowing a precise formulation of the condition of optimal trade-off between performance and metabolic cost. In the 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.

  2. 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.

  3. Optically trapped and driven paddle-wheel

    Science.gov (United States)

    Asavei, Theodor; Nieminen, Timo A.; Loke, Vincent L. Y.; Stilgoe, Alexander B.; Bowman, Richard; Preece, Daryl; Padgett, Miles J.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina

    2013-06-01

    We demonstrate the control and rotation of an optically trapped object, an optical paddle-wheel, with the rotation direction normal to the beam axis. This is in contrast to the usual situation where the rotation is about the beam axis. The paddle-wheel can be optically driven and moved to any position in the field of view of the microscope, which can be of interest for various biological applications where controlled application of a fluid flow is needed in a particular location and in a specific direction. This is of particular interest in signal transduction studies in cells, especially when a cell is flat and spread out on a surface.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. A refinement driven component-based design

    DEFF Research Database (Denmark)

    Chen, Zhenbang; Liu, Zhiming; Ravn, Anders Peter;

    2007-01-01

    to integrate sophisticated checkers, generators and transformations. A feasible approach to ensuring high quality of such add-ins is to base them on sound formal foundations. This paper summarizes our research on the Refinement of Component and Object Systems (rCOS) and illustrates it with experiences from...... the work on the Common Component Modelling Example (CoCoME). This gives evidence that the formal techniques developed in rCOS can be integrated into a model-driven development process and shows where it may be integrated in computer-aided software engineering (CASE) tools for adding formally supported...

  10. Challenges of Data-driven Healthcare Management

    DEFF Research Database (Denmark)

    Bossen, Claus; Danholt, Peter; Ubbesen, Morten Bonde

    activity and financing and relies of extensive data entry, reporting and calculations. This has required the development of new skills, work and work roles. The second case concerns a New Governance project aimed at developing new performance indicators for healthcare delivery as an alternative to DRG....... Here, a core challenge is select indicators and actually being able to acquire data upon them. The two cases point out that data-driven healthcare requires more and new kinds of work for which new skills, functions and work roles have to be developed....

  11. Roughening transitions of driven surface growth

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, A. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)]|[Departamento de Mathematicas, Escuela Politecnica Superior, Universidad Carlos III, E-28911 Leganes, Madrid (Spain); Cai, D.; Gronbech-Jensen, N.; Bishop, A.R. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Wang, Z.J. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)]|[The James Franck Institute, 5640 Ellis Avenue, Chicago, Illinois 60637 (United States)

    1995-05-15

    A model of surface growth given by a two-dimensional discrete, driven, damped sine-Gordon equation is studied using Langevin dynamics. Our large-scale simulations show that the equilibrium Kosterlitz-Thouless roughening transition splits into two crossovers (or transitions) under the external force of, e.g., vapor-surface chemical potential difference. Three different regimes are characterized in terms of roughness, growth rate, and height-height correlations---the onset of a rough phase is accompanied by the suppression of oscillatory growth. Our results are interpreted consistently within a renormalization-group framework. We discuss the generality of our conclusions and propose specific comparisons with experiments.

  12. 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.

  13. Odd-frequency superconductivity in driven systems

    Science.gov (United States)

    Triola, Christopher; Balatsky, Alexander V.

    2016-09-01

    We show that Berezinskii's classification of the symmetries of Cooper pair amplitudes holds for driven systems even in the absence of translation invariance. We then consider a model Hamiltonian for a superconductor coupled to an external driving potential and, treating the drive as a perturbation, we investigate the corrections to the anomalous Green's function, density of states, and spectral function. We find that in the presence of an external drive the anomalous Green's function develops terms that are odd in frequency and that the same mechanism responsible for these odd-frequency terms generates additional features in the density of states and spectral function.

  14. 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

  15. 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.

  16. Accelerator driven sub-critical core

    Science.gov (United States)

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  17. Light Sailboats: Laser driven autonomous microrobots

    CERN Document Server

    Búzás, Anrdás; Mathesz, Anna; Oroszi, László; Vizsnyiczai, Gaszton; Vicsek, Tamás; Ormos, Pál; 10.1063/1.4737646

    2012-01-01

    We introduce a system of light driven microscopic autonomous moving particles that move on a flat surface. The design is simple, yet effective: Micrometer sized objects with wedge shape are produced by photopolymerization, they are covered with a reflective surface. When the area of motion is illuminated perpendicularly from above, the light is deflected to the side by the wedge shaped objects, in the direction determined by the position and orientation of the particles. The momentum change during reflection provides the driving force for an effectively autonomous motion. The system is an efficient tool to study self propelled microscopic robots.

  18. 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.

  19. 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.

  20. Control Optimization of Solar Thermally Driven Chillers

    Directory of Open Access Journals (Sweden)

    Antoine Dalibard

    2016-10-01

    Full Text Available Many installed solar thermally driven cooling systems suffer from high auxiliary electric energy consumption which makes them not more efficient than conventional compression cooling systems. A main reason for this is the use of non-efficient controls with constant set points that do not allow a chiller power modulation at partial-load and therefore lead to unnecessary high power consumption of the parasitics. The aims of this paper are to present a method to control efficiently solar thermally driven chillers, to demonstrate experimentally its applicability and to quantify the benefits. It has been shown that the cooling capacity of a diffusion absorption chiller can be modulated very effectively by adjusting both the temperature and the flow rate of the cooling water. With the developed approach and the use of optimization algorithms, both the temperature and the flow rate can be controlled simultaneously in a way that the cooling load is matched and the electricity consumption is minimized. Depending on the weather and operating conditions, electricity savings between 20% and 60% can be achieved compared to other tested control approaches. The highest savings are obtained when the chiller is operated at partial load. The presented method is not restricted to solar cooling systems and can also be applied to other conventional heating ventilation and air conditioning (HVAC systems.

  1. 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.

  2. The Frankfurt RF-driven ion source

    CERN Document Server

    Beller, Peter; Klein, H; Maaser, A; Volk, K; Weber, M

    2000-01-01

    An RF-driven volume ion source based on the high efficiency ion source (HIEFS) has been developed at the Institut fuer Angewandte Physik in Frankfurt. The RF-driven ion source operates at a frequency of 3.5 MHz with a maximum duty factor of 10%. Using an 11 kW RF-amplifier a He sup + -beam with a current of 82 mA as well as an oxygen beam with a current of 39 mA and an O sup + -fraction of 90% could be extracted. Experiments were done to study the operating conditions of the ion source. For the working gases helium and oxygen the emission current density in dependence on several ion source parameters was investigated. Furthermore, the energy distribution of the electrons and ions in the plasma as well as the beam composition for several working gases were studied. This article will give a detailed description of the ion source and the experimental setup. In addition, various dependencies between the plasma parameters and the emission current density, the energy distribution of electrons and ions and the beam ...

  3. 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.

  4. 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.

  5. 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.

  6. Solar Dynamo Driven by Periodic Flow Oscillation

    Science.gov (United States)

    Mayr, Hans G.; Hartle, Richard E.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    We have proposed that the periodicity of the solar magnetic cycle is determined by wave mean flow interactions analogous to those driving the Quasi Biennial Oscillation in the Earth's atmosphere. Upward propagating gravity waves would produce oscillating flows near the top of the radiation zone that in turn would drive a kinematic dynamo to generate the 22-year solar magnetic cycle. The dynamo we propose is built on a given time independent magnetic field B, which allows us to estimate the time dependent, oscillating components of the magnetic field, (Delta)B. The toroidal magnetic field (Delta)B(sub phi) is directly driven by zonal flow and is relatively large in the source region, (Delta)(sub phi)/B(sub Theta) much greater than 1. Consistent with observations, this field peaks at low latitudes and has opposite polarities in both hemispheres. The oscillating poloidal magnetic field component, (Delta)B(sub Theta), is driven by the meridional circulation, which is difficult to assess without a numerical model that properly accounts for the solar atmosphere dynamics. Scale-analysis suggests that (Delta)B(sub Theta) is small compared to B(sub Theta) in the dynamo region. Relative to B(sub Theta), however, the oscillating magnetic field perturbations are expected to be transported more rapidly upwards in the convection zone to the solar surface. As a result, (Delta)B(sub Theta) (and (Delta)B(sub phi)) should grow relative to B(sub Theta), so that the magnetic fields reverse at the surface as observed. Since the meridional and zonai flow oscillations are out of phase, the poloidal magnetic field peaks during times when the toroidal field reverses direction, which is observed. With the proposed wave driven flow oscillation, the magnitude of the oscillating poloidal magnetic field increases with the mean rotation rate of the fluid. This is consistent with the Bode-Blackett empirical scaling law, which reveals that in massive astrophysical bodies the magnetic moment tends

  7. The mechanics of gravity-driven faulting

    Science.gov (United States)

    Barrows, L.; Barrows, V.

    2010-04-01

    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 the fault. They must exist if gravity

  8. 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

  9. The Energetics of Gravity Driven Faulting

    Science.gov (United States)

    Barrows, L.

    2007-12-01

    Faulting can result from either of two different mechanisms. These involve fundamentally different energetics. In displacement-bounded faulting, locked-in elastic strain energy is transformed into seismic waves plus work done in the fault zone. Elastic rebound is an example of displacement-bounded faulting. 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 seismic waves plus work done in the fault zone and half goes into an increase in locked-in elastic strain. In displacement-bounded faulting 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. 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 topography and internal stress-causing density variations is equally split between the seismic waves plus work done in the fault zone 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 the fault. They must exist if gravity participates in the energetics of the faulting process. From the perspective of gravitational tectonics, the gravity collapse mechanism is direct and simple. The related mechanics are a little more

  10. Resource-Driven Scheduling Implementation in Malaysian Construction Industry

    OpenAIRE

    Aftab Hameed Memon; Rosli Mohammad Zin

    2011-01-01

    Resource-driven scheduling techniques focus on resource. Their objective is to schedule activities so that a project dead line is met using predefined resource availability limits. This paper reports about the status of resource-driven scheduling implementation in Malaysian construction industry. An investigation Survey was conducted to determine the level of resource-driven scheduling and factors affecting the concerned implementation. Construction Firm registered under G7 (A Class), G6 (B c...

  11. 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.

  12. 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...

  13. 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.

  14. Instability in electromagnetically driven flows. II

    Science.gov (United States)

    Rodriguez Imazio, Paola; Gissinger, Christophe

    2016-03-01

    In a previous paper, we have reported numerical simulations of the magnetohydrodynamic flow driven by a travelling magnetic field 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.

  15. Arc-driven rail gun research

    Science.gov (United States)

    Ray, P. K.

    1984-01-01

    The equations describing the performance of an inductively-driven rail gun are analyzed numerically. Friction between the projectile and rails is included through an empirical formulation. The equations are applied to the experiment of Rashleigh and Marshall to obtain an estimate of energy distribution in rail guns as a function of time. The effect of frictional heat dissipation on the bore of the gun is calculated. The mechanism of plasma and projectile acceleration in a dc rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipated in the plasma with the radiation heat loss, the properties of the plasma are determined.

  16. 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...

  17. 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.

  18. 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.

  19. A Solvable Symbiosis-Driven Growth Model

    Institute of Scientific and Technical Information of China (English)

    KE Jian-Hong; LIN Zhen-Quan; CHEN Xiao-Shuang

    2006-01-01

    We introduce a two-species symbiosis-driven growth model, in which two species can mutually benefit for their monomer birth and the self-death of each species simultaneously occurs. By means of the generalized rate equation, we investigate the dynamic evolution of the system under the monodisperse initial condition. It is found that the kinetic behaviour of the system depends crucially on the details of the rate kernels as well as the initial concentration distributions. The cluster size distribution of either species cannot be scaled in most cases;while in some special cases, they both consistently take the universal scaling form. Moreover, in some cases the system may undergo a gelation transition and the pre-gelation behaviour of the cluster size distributions satisfies the scaling form in the vicinity of the gelation point. On the other hand, the two species always live and die together.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. Repetitive control of electrically driven robot manipulators

    Science.gov (United States)

    Fateh, Mohammad Mehdi; Ahsani Tehrani, Hojjat; Karbassi, Seyed Mehdi

    2013-04-01

    This article presents a novel robust discrete repetitive control of electrically driven robot manipulators for tracking of a periodic trajectory. We propose a novel model, which presents the highly non-linear dynamics of robot manipulator in the form of linear discrete-time time-varying system. Based on the proposed model, we develop a two-term control law. The first term is an ordinary time-optimal and minimum-norm (TOMN) control by employing parametric controllers to guarantee stability. The second term is a novel robust control to improve the control performance in the face of uncertainties. The robust control estimates and compensates uncertainties including the parametric uncertainty, unmodelled dynamics and external disturbances. Performance of the proposed method is compared with two discrete methods, namely the TOMN control and an adaptive iterative learning (AIL) control. Simulation results confirm superiority of the proposed method in terms of the convergence speed and precision.

  5. Peltier effect in strongly driven quantum wires

    Science.gov (United States)

    Mierzejewski, M.; Crivelli, D.; Prelovšek, P.

    2014-08-01

    We study a microscopic model of a thermocouple device with two connected correlated quantum wires driven by a constant electric field. In such a closed system we follow the time and position dependence of the entropy density using the concept of the reduced density matrix. At weak driving, the initial changes of the entropy at the junctions can be described by the linear Peltier response. At longer times the quasiequilibrium situation is reached with well defined local temperatures which increase due to an overall Joule heating. On the other hand, a strong electric field induces a nontrivial nonlinear thermoelectric response, e.g., the Bloch oscillations of the energy current. Moreover, we show for the doped Mott insulators that strong driving can reverse the Peltier effect.

  6. 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...

  7. Brane cosmology driven by the rolling tachyon

    CERN Document Server

    Mukohyama, S

    2002-01-01

    Brane cosmology driven by the tachyon rolling down to its ground state is investigated. We adopt an effective field theoretical description for the tachyon and Randall-Sundrum type brane world scenario. After formulating basic equations, we show that the standard cosmology with a usual scalar field can mimic the low energy behavior of the system near the tachyon ground state. We also investigate qualitative behavior of the system beyond the low energy regime for positive, negative and vanishing 4-dimensional effective cosmological constant $\\Lambda_4=\\kappa_5^4V(T_0)^2/12-|\\Lambda_5|/2$, where $\\kappa_5$ and $\\Lambda_5$ are 5-dimensional gravitational coupling constant and (negative) cosmological constant, respectively, and $V(T_0)$ is the (positive) tension of the brane in the tachyon ground state. In particular, for $\\Lambda_4<0$ the tachyon never settles down to its potential minimum and the universe eventually hits a big-crunch singularity.

  8. 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...

  9. 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.

  10. 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....

  11. 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.

  12. Statistics of Reconnection-Driven Turbulence

    CERN Document Server

    Kowal, Grzegorz; Lazarian, Alex; Vishniac, Ethan T

    2016-01-01

    Magnetic reconnection is a process that changes magnetic field topology in highly conducting fluids. Within the standard Sweet-Parker model, this process would be too slow to explain observations (e.g. solar flares). In reality, the process must be ubiquitous as astrophysical fluids are magnetized and motions of fluid elements necessarily entail crossing of magnetic frozen-in field lines and magnetic reconnection. In the presence of turbulence, the reconnection is independent of microscopic plasma properties, and may be much faster than previously thought, as proposed in Lazarian & Vishniac (1999) and tested in Kowal et al. (2009, 2012). However, the considered turbulence in the Lazarian-Vishniac model was imposed externally. In this work we consider reconnection-driven magnetized turbulence in realistic three-dimensional geometry initiated by stochastic noise. We demonstrate through numerical simulations that the stochastic reconnection is able to self-generate turbulence through interactions between the...

  13. Zonostrophic instability driven by discrete particle noise

    CERN Document Server

    St-Onge, D A

    2016-01-01

    The consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provides a new interpretation of the random forcing that is ubiquitously invoked in stochastic models such as the second-order cumulant expansion (CE2) or stochastic structural instability theory (SSST); neither intrinsic turbulence nor coupling to extrinsic turbulence is required. A representative calculation of the zonostrophic neutral curve is made for a simple two-field model of toroidal ion-temperature-gradient-driven modes. To the extent that the damping of zonal flows is controlled by the ion--ion collision rate, the point of zonostrophic instability is independent of that rate.

  14. Runtime Adaptability driven by Negotiable Quality Requirements

    CERN Document Server

    Mosincat, Adina

    2011-01-01

    Two of the common features of business and the web are diversity and dynamism. Diversity results in users having different preferences for the quality requirements of a system. Diversity also makes possible alternative implementations for functional requirements, called variants, each of them providing different quality. The quality provided by the system may vary due to different variant components and changes in the environment. The challenge is to dynamically adapt to quality variations and to find the variant that best fulfills the multi-criteria quality requirements driven by user preferences and current runtime conditions. For service-oriented systems this challenge is augmented by their distributed nature and lack of control over the constituent services and their provided quality of service (QoS). We propose a novel approach to runtime adaptability that detects QoS changes, updates the system model with runtime information, and uses the model to select the variant to execute at runtime. We introduce n...

  15. Fluid-driven fractures in brittle hydrogels

    Science.gov (United States)

    O'Keeffe, Niall; Linden, Paul

    2016-11-01

    Hydraulic fracturing is a process in which fluid is injected deep underground at high pressures that can overcome the strength of the surrounding matrix. This results in an increase of surface area connected to the well bore and thus allows extraction of natural gas previously trapped in a rock formation. We experimentally study the physical mechanisms of these fluid-driven fractures in low permeability reservoirs where the leak-off of fracturing fluid is considered negligible. This is done through the use of small scale experiments on transparent and brittle, heavily cross-linked hydrogels. The propagation of these fractures can be split into two distinct regimes depending on whether the dominant energy dissipation mechanism is viscous flow or material toughness. We will analyse crack growth rates, crack thickness and tip shape in both regimes. Moreover, PIV techniques allow us to explore the flow dynamics within the fracture, which is crucial in predicting transport of proppants designed to prevent localisation of cracks.

  16. Model Driven Software Development for Agricultural Robotics

    DEFF Research Database (Denmark)

    Larsen, Morten

    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...

  17. 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.

  18. Mesoscopic fluctuations in biharmonically driven flux qubits

    Science.gov (United States)

    Ferrón, Alejandro; Domínguez, Daniel; Sánchez, María José

    2017-01-01

    We investigate flux qubits driven by a biharmonic magnetic signal, with a phase lag that acts as an effective time reversal broken parameter. The driving induced transition rate between the ground and the excited state of the flux qubit can be thought of as an effective transmittance, profiting from a direct analogy between interference effects at avoided level crossings and scattering events in disordered electronic systems. For time scales prior to full relaxation, but large compared to the decoherence time, this characteristic rate has been accessed experimentally by Gustavsson et al. [Phys. Rev. Lett. 110, 016603 (2013)], 10.1103/PhysRevLett.110.016603 and its sensitivity with both the phase lag and the dc flux detuning explored. In this way, signatures of universal conductance fluctuationslike effects have been analyzed and compared with predictions from a phenomenological model that only accounts for decoherence, as a classical noise. Here we go beyond the classical noise model and solve the full dynamics of the driven flux qubit in contact with a quantum bath employing the Floquet-Born-Markov master equation. Within this formalism, the computed relaxation and decoherence rates turn out to be strongly dependent on both the phase lag and the dc flux detuning. Consequently, the associated pattern of fluctuations in the characteristic rates display important differences with those obtained within the mentioned phenomenological model. In particular, we demonstrate the weak localizationlike effect in the average values of the relaxation rate. Our predictions can be tested for accessible but longer time scales than the current experimental times.

  19. 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.

  20. 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.

  1. Current-driven plasma acceleration versus current-driven energy dissipation. I - Wave stability theory

    Science.gov (United States)

    Kelly, A. J.; Jahn, R. G.; Choueiri, E. Y.

    1990-01-01

    The dominant unstable electrostatic wave modes of an electromagnetically accelerated plasma are investigated. The study is the first part of a three-phase program aimed at characterizing the current-driven turbulent dissipation degrading the efficiency of Lorentz force plasma accelerators such as the MPD thruster. The analysis uses a kinetic theory that includes magnetic and thermal effects as well as those of an electron current transverse to the magnetic field and collisions, thus combining all the features of previous models. Analytical and numerical solutions allow a detailed description of threshold criteria, finite growth behavior, destabilization mechanisms and maximized-growth characteristics of the dominant unstable modes. The lower hybrid current-driven instability is implicated as dominant and was found to preserve its character in the collisional plasma regime.

  2. 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.

  3. 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.

  4. Antimatter Plasmas in a Multipole Trap for Antihydrogen

    CERN Document Server

    Andresen, G B; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Gomberoff, K; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Telle, H H; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2007-01-01

    We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage lifetimes of antiproton and positron plasmas in the combined Penning-neutral trap, and compared these to lifetimes without the neutral trap fields. The magnetic well depth was 0.6 T, deep enough to trap ground state antihydrogen atoms of up to about 0.4 K in temperature. We have demonstrated that both particle species can be stored for times long enough to permit antihydrogen production and trapping studies.

  5. Physics of antimatter-matter reactions for interstellar propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.L. Jr.

    1986-08-22

    At the stage of the antiproton-nucleon annihilation chain of events relevant to propulsion the annihilation produces energetic charged pions and gamma rays. If annihilation occurs in a complex nucleus, protons, neutrons, and other nuclear fragments are also produced. The charge, number, and energy of the annihilation products are such that annihilation rocket engine concepts involving relatively low specific impulse (I/sub sp/ approx. = 1000 to 2000 s) and very high I/sub sp/ (3 x 10/sup 7/ s) appear feasible and have efficiencies on the order of 50% for annihilation energy to propulsion energy conversion. At I/sub sp/'s of around 15,000 s, however, it may be that only the kinetic energy of the charged nuclear fragments can be utilized for propulsion in engines of ordinary size. An estimate of this kinetic energy was made from known pieces of experimental and theoretical information. Its value is about 10% of the annihilation energy. Control over the mean penetration depth of protons into matter prior to annihilation is necessary so that annihilation occurs in the proper region within the engine. Control is possible by varying the antiproton kinetic energy to obtain a suitable annihilation cross section. The annihilation cross section at low energies is on the order of or larger than atomic areas due to a rearrangement reaction, but it is very low at high energy where its value is closer to nuclear areas.

  6. 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)

  7. 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.

  8. 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)

  9. 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

  10. Implementation readiness for user-driven innovation in business networks

    DEFF Research Database (Denmark)

    Lassen, Astrid Heidemann; Jacobsen, Alexia

    2013-01-01

    In this paper we further develop the concept of implementation readiness of user driven innovation in business networks by focusing on how implementation readiness activities are in fact needed not only at the early stages of such network collaboration, but continuously throughout the process...... of developing user-driven innovation in business networks....

  11. Educational Accountability: A Qualitatively Driven Mixed-Methods Approach

    Science.gov (United States)

    Hall, Jori N.; Ryan, Katherine E.

    2011-01-01

    This article discusses the importance of mixed-methods research, in particular the value of qualitatively driven mixed-methods research for quantitatively driven domains like educational accountability. The article demonstrates the merits of qualitative thinking by describing a mixed-methods study that focuses on a middle school's system of…

  12. Theory-Driven Science and Naive Empiricism in Counseling Psychology.

    Science.gov (United States)

    Strong, Stanley R.

    1991-01-01

    Asserts that counseling psychologists' aversion to theory-driven science and their enthusiasm for naive empiricism impede scientific progress. Identifies "received view" of science as theory-driven science, points out symptoms and consequences of the failure to apply this view, and argues that greater scientific progress will result from moving…

  13. 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

  14. Optimal Control of Stochastic Systems Driven by Fractional Brownian Motions

    Science.gov (United States)

    2014-10-09

    motions and other stochastic processes. For the control of both continuous time and discrete time finite dimensional linear systems with quadratic...problems for stochastic partial differential equations driven by fractional Brownian motions are explicitly solved. For the control of a continuous time...2010 30-Jun-2014 Approved for Public Release; Distribution Unlimited Final Report: Optimal Control of Stochastic Systems Driven by Fractional Brownian

  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. Control of rotor function in light-driven molecular motors

    NARCIS (Netherlands)

    Lubbe, Anouk S.; Ruangsupapichat, Nopporn; Caroli, Giuseppe; Feringa, Ben L.

    2011-01-01

    A study is presented on the control of rotary motion of an appending rotor unit in a light-driven molecular motor. Two new light driven molecular motors were synthesized that contain aryl groups connected to the stereogenic centers. The aryl groups behave as bidirectional free rotors in three of the

  17. High dimensional data driven statistical mechanics.

    Science.gov (United States)

    Adachi, Yoshitaka; Sadamatsu, Sunao

    2014-11-01

    In "3D4D materials science", there are five categories such as (a) Image acquisition, (b) Processing, (c) Analysis, (d) Modelling, and (e) Data sharing. This presentation highlights the core of these categories [1]. Analysis and modellingA three-dimensional (3D) microstructure image contains topological features such as connectivity in addition to metric features. Such more microstructural information seems to be useful for more precise property prediction. There are two ways for microstructure-based property prediction (Fig. 1A). One is 3D image data based modelling such as micromechanics or crystal plasticity finite element method. The other one is a numerical microstructural features driven machine learning approach such as artificial neural network or Bayesian estimation method. It is the key to convert the 3D image data into numerals in order to apply the dataset to property prediction. As a numerical feature of microstructures, grain size, number of density, of particles, connectivity of particles, grain boundary connectivity, stacking degree, clustering etc. should be taken into consideration. These microstructural features are so-called "materials genome". Among those materials genome, we have to find out dominant factors to determine a focused property. The dominant factorzs are defined as "descriptor(s)" in high dimensional data driven statistical mechanics.jmicro;63/suppl_1/i4/DFU086F1F1DFU086F1Fig. 1.(a) A concept of 3D4D materials science. (b) Fully-automated serial sectioning 3D microscope "Genus_3D". (c) Materials Genome Archive (JSPS). Image acquisitionIt is important for researchers to choice a 3D microscope from various microscopes depending on a length-scale of a focused microstructure. There is a long term request to acquire a 3D microstructure image more conveniently. Therefore a fully automated serial sectioning 3D optical microscope "Genus_3D" (Fig. 1B) has been developed and nowadays it is commercially available. A user can get a good

  18. Sandpile Dynamics Driven by Degree on Scale-Free Networks

    Institute of Scientific and Technical Information of China (English)

    YIN Yan-Ping; ZHANG Duan-Ming; PAN Gui-Jun; HE Min-Hua

    2007-01-01

    @@ We introduce a sandpile model driven by degree on scale-free networks, where the perturbation is triggered at nodes with the same degree. We numerically investigate the avalanche behaviour of sandpile driven by different degrees on scale-free networks. It is observed that the avalanche area has the same behaviour with avalanche size. When the sandpile is driven at nodes with the minimal degree, the avalanches of our model behave similarly to those of the original Bak-Tang-Wiesenfeld (BTW) model on scale-free networks. As the degree of driven nodes increases from the minimal value to the maximal value, the avalanche distribution gradually changes from a clean power law, then a mixture of Poissonian and power laws, finally to a Poisson-like distribution. The average avalanche area is found to increase with the degree of driven nodes so that perturbation triggered on higher-degree nodes will result in broader spreading of avalanche propagation.

  19. 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.

  20. 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

  1. Nonlinear modeling of thermoacoustically driven energy cascade

    Science.gov (United States)

    Gupta, Prateek; Scalo, Carlo; Lodato, Guido

    2016-11-01

    We present an investigation of nonlinear energy cascade in thermoacoustically driven high-amplitude oscillations, from the initial weakly nonlinear regime to the shock wave dominated limit cycle. We develop a first principle based quasi-1D model for nonlinear wave propagation in a canonical minimal unit thermoacoustic device inspired by the experimental setup of Biwa et al.. Retaining up to quadratic nonlinear terms in the governing equations, we develop model equations for nonlinear wave propagation in the proximity of differentially heated no-slip boundaries. Furthermore, we discard the effects of acoustic streaming in the present study and focus on nonlinear energy cascade due to high amplitude wave propagation. Our model correctly predicts the observed exponential growth of the thermoacoustically amplified second harmonic, as well as the energy transfer rate to higher harmonics causing wave steepening. Moreover, we note that nonlinear coupling of local pressure with heat transfer reduces thermoacoustic amplification gradually thus causing the system to reach limit cycle exhibiting shock waves. Throughout, we verify the results from the quasi-1D model with fully compressible Navier-Stokes simulations.

  2. Radiation driven implosion and triggered star formation

    CERN Document Server

    Bisbas, Thomas G; Whitworth, Anthony P; Hubber, David A; Walch, Stefanie

    2011-01-01

    We present simulations of initially stable isothermal clouds exposed to ionising 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 and an HEALPix-based photo-ionisation algorithm to simulate the propagation of the ionising radiation and the resulting dynamical evolution of the cloud. We find that the incident ionising flux, $\\Phi_{_{\\rm LyC}}$, is the critical parameter determining the cloud evolution. At moderate fluxes, a large fraction of the cloud mass is converted into stars. As the flux is increased, the fraction of the cloud mass that is converted into stars and the mean masses of the individual stars both decrease. Very high fluxes simply disperse the cloud. Newly-formed stars tend to be concentrated along the central axis of the cloud (i.e. the axis pointing in the direction of the incident flux). For given cloud parameters, the time, $t_{_\\star}$, at which star for...

  3. 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.

  4. 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.

  5. 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...

  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. Linac-driven spallation-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jason, A.J.

    1995-05-01

    Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications.

  8. 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.

  9. A colalborative environment for information driven safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Mark R [Los Alamos National Laboratory; Michel, Kelly D [Los Alamos National Laboratory

    2010-09-15

    For two decades, the IAEA has recognized the need for a comprehensive and strongly integrated Knowledge Management system to support its Information Driven Safeguards activities. In the past, plans for the development of such a system have progressed slowly due to concerns over costs and feasibility. In recent years, Los Alamos National Laboratory has developed a knowledge management system that could serve as the basis for an IAEA Collaborative Environment (ICE). The ICE derivative knowledge management system described in this paper addresses the challenge of living in an era of information overload coupled with certain knowledge shortfalls. The paper describes and defines a system that is flexible, yet ensures coordinated and focused collaboration, broad data evaluation capabilities, architected and organized work flows, and improved communications. The paper and demonstration of ICE will utilize a hypothetical scenario to highlight the functional features that facilitate collaboration amongst and between information analysts and inspectors. The scenario will place these two groups into a simulated planning exercise for a safeguards inspection drawing upon past data acquisitions, inspection reports, analyst conclusions, and a coordinated walk-through of a 3-D model of the facility. Subsequent to the conduct of the simulated facility inspection, the detection of an anomaly and pursuit of follow up activities will illustrate the event notification, information sharing, and collaborative capabilities of the system. The use of a collaborative environment such as ICE to fulfill the complicated knowledge management demands of the Agency and facilitate the completion of annual State Evaluation Reports will also be addressed.

  10. Optimal design of capacitor-driven coilgun

    Science.gov (United States)

    Kim, Seog-Whan; Jung, Hyun-Kyo; Hahn, Song-Yop

    1994-03-01

    This paper presents an analysis and optimal design of a capacitor-driven inductive coilgun. An equivalent circuit is used for a launch simulation of the coilgun. The circuit equations are solved together with the equation of motion of the projectile by using the Runge-Kutta method. The numerical results are compared with the experimental values to verify the usefulness of the developed simulation program. It is shown that the numerical and the experimental results are in a good agreement. In the design of the system the optimization is achieved by employing the genetic algorithm. The resultant specifications of the coilgun optimally designed by the proposed algorithm are tested by experiment. Finally the obtained results are compared with those designed by approximate equations and by linear search methods as well. It is found that the proposed algorithm gives a better result in the energy efficiency of the system, namely it enables one to obtain a higher muzzle velocity of the projectile with the same amount of energy.

  11. 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.

  12. 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.

  13. Shock driven multiphase flow with particle evaporation

    Science.gov (United States)

    Dahal, Jeevan; McFarland, Jacob

    2016-11-01

    The computational study of the shock driven instability of a multiphase system with particle evaporation is presented. The particle evaporation modifies the evolution of the interface due to the addition of the vapor phase to the gas. The effects can be quantitatively measured by studying various gas parameters like density, temperature, vorticity and particle properties like diameter and temperature. In addition, the size distribution of particles also modifies the development of instability as the larger size particles damp the evolution of interface in comparison to the smaller size particles. The simulation results are presented to study these effects using FLASH developed at the FLASH Center at the University of Chicago. The capabilities of FLASH for particle modeling were extended using the Particle in Cell (PIC) technique for coupling of mass, momentum, and energy between the particle and carrier gas. A seeded cylinder of gas with particles having either a single radius or a distribution of radii was studied. The enstrophy production and destruction mechanisms were explored to understand the reason for change in vorticity with particle size.

  14. Designing and operating electrostatically driven microengines

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, M.S.; Sniegowski, J.J.; Miller, S.L.; LaVigne, G.F.

    1998-02-01

    Microelectromechanical engines that convert the linear outputs from dual orthogonal electrostatic actuators to rotary motion were first developed in 1993. Referred to as microengines, these early devices demonstrated the potential of microelectromechanical technology, but, as expected from any first-of-its-kind device, were not yet optimized. Yield was relatively low, and the 10 micronewtons of force generated by the actuators was not always enough to ensure reliable operation. Since initial development, these engines have undergone a continuous series of significant improvements on three separate fronts: design, fabrication, and electrical activation. Although all three areas will be discussed, emphasis will be on aspects related to mechanical design and generation of the electrical waveforms used to drive these devices. Microtransmissions that dramatically increase torque will also be discussed. Electrostatically driven microengines can be operated at hundreds of thousands of revolutions per minute making large gear reduction ratios feasible; overall ratios of 3,000,000:1 have been successfully demonstrated. Today`s microengines have evolved into high endurance (one test device has seen over 7,000,000,000 revolutions), high yield, robust devices that have become the primary actuation source for MicroElectroMechanical Systems (MEMS) at Sandia National Laboratories.

  15. An experimental investigation of blast driven turbulence

    Science.gov (United States)

    Musci, Benjamin; Ranjan, Devesh

    2016-11-01

    In the Georgia Tech Shock and Advanced Mixing Lab, a facility is being built to study blast driven turbulence. Motivated by the discrepancies observed between actual and modeled supernovae, this facility aims to resolve the important spatial scales in the extensive mixing of the outer layers. These outer layers will be modeled by subjecting two-three gases of varying density to a blast wave generated by Exploding Bridge Wires. The blast wave's interaction with perturbations at the gaseous, membrane-less, interfaces will induce the Richtmeyer-Meshkov or Rayleigh Taylor Instability, depending on the acceleration history and perturbation amplitude. Through the use of simultaneous Particle Image Velocimetry, and Planar Laser Induced Fluorescence, this project aims to determine the effect of interface initial conditions on turbulence. A 2D Diverging Wedge and 3D Diverging Conical Tube are being built to enable repeatable blast-wave production, continuous optical viewing of the flow, reproducible multi-layer interface creation, and the collection of simultaneous density-velocity measurements to directly measure turbulent quantities. The preliminary analysis informing the design of this facility, the construction progress, and updates on newly realized design constraints are presented.

  16. 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.

  17. 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.

  18. 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.

  19. Thermally driven upslope flow in mountainous terrain

    Science.gov (United States)

    Liberzon, Dan; Hocut, Christopher; Fernando, Harindra; Environmental Fluid Dynamics Team

    2011-11-01

    Buoyancy driven up-slope flow and its separation from mountain apex are two important processes that determine meso and regional flows in mountainous areas. Such flow configurations have applications from mountain meteorology to large scale monsoonal circulation. A combined experimental and theoretical study toward improving our understanding of the mechanisms governing upslope flow processes, in particular, generation of upstream circulating cells and plume rise at the apex is presented. The experiments were performed in a 1.25x.35x.3 m water tank, using an inclined (10 to 30 degrees from the horizontal) electrical foil as the heated slope. Under certain condition the flow configuration produced stable circulation cells and rising limited plumes of finite height. Particle Tracking Velocimetry and flow visualization techniques were used for the diagnostics of velocity field and plume rise height, and relevant salient dimensionless quantities were evaluated in terms of governing parameters. Theoretical arguments are presented to explain the results. Parameter ranges for the appearance of characteristic flow patterns are also delineated.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. Deterministically Driven Avalanche Models of Solar Flares

    Science.gov (United States)

    Strugarek, Antoine; Charbonneau, Paul; Joseph, Richard; Pirot, Dorian

    2014-08-01

    We develop and discuss the properties of a new class of lattice-based avalanche models of solar flares. These models are readily amenable to a relatively unambiguous physical interpretation in terms of slow twisting of a coronal loop. They share similarities with other avalanche models, such as the classical stick-slip self-organized critical model of earthquakes, in that they are driven globally by a fully deterministic energy-loading process. The model design leads to a systematic deficit of small-scale avalanches. In some portions of model space, mid-size and large avalanching behavior is scale-free, being characterized by event size distributions that have the form of power-laws with index values, which, in some parameter regimes, compare favorably to those inferred from solar EUV and X-ray flare data. For models using conservative or near-conservative redistribution rules, a population of large, quasiperiodic avalanches can also appear. Although without direct counterparts in the observational global statistics of flare energy release, this latter behavior may be relevant to recurrent flaring in individual coronal loops. This class of models could provide a basis for the prediction of large solar flares.

  6. Deterministically Driven Avalanche Models of Solar Flares

    CERN Document Server

    Strugarek, Antoine; Joseph, Richard; Pirot, Dorian

    2014-01-01

    We develop and discuss the properties of a new class of lattice-based avalanche models of solar flares. These models are readily amenable to a relatively unambiguous physical interpretation in terms of slow twisting of a coronal loop. They share similarities with other avalanche models, such as the classical stick--slip self-organized critical model of earthquakes, in that they are driven globally by a fully deterministic energy loading process. The model design leads to a systematic deficit of small scale avalanches. In some portions of model space, mid-size and large avalanching behavior is scale-free, being characterized by event size distributions that have the form of power-laws with index values, which, in some parameter regimes, compare favorably to those inferred from solar EUV and X-ray flare data. For models using conservative or near-conservative redistribution rules, a population of large, quasiperiodic avalanches can also appear. Although without direct counterparts in the observational global st...

  7. Pressure driven flow in porous tubular membranes

    Science.gov (United States)

    Tilton, Nils; Martinand, Denis; Serre, Eric; Lueptow, Richard

    2011-11-01

    We consider the steady laminar flow of a Newtonian incompressible fluid in a porous tubular membrane with pressure-driven transmembrane flow. Due to its fundamental importance to membrane filtration systems, this flow has been studied extensively both analytically and numerically, yet a robust analytic solution has not been found. The problem is challenging due to the coupling between the transmembrane pressure and velocity with the simultaneous coupling between the axial pressure gradient and the axial velocity. We present a robust analytical solution which incorporates Darcy's law on the membrane surface. The solution is in the form of an asymptotic expansion about a small parameter related to the membrane permeability. We verify the analytical solution with comparison to 2-D spectral direct numerical simulations of ultrafiltration and microfiltration systems with typical operating conditions, as well as extreme cases of cross-flow reversal and axial flow exhaustion. In all cases, the agreement between the analytical and numerical results is excellent. Finally, we use the analytical and numerical results to provide guidelines about when common simplifying assumptions about the permeate flow may be made. Specifically, the assumptions of a parabolic axial velocity profile and uniform transmembrane velocity are valid only for small permeabilities.

  8. Auxin-driven patterning with unidirectional fluxes.

    Science.gov (United States)

    Cieslak, Mikolaj; Runions, Adam; Prusinkiewicz, Przemyslaw

    2015-08-01

    The plant hormone auxin plays an essential role in the patterning of plant structures. Biological hypotheses supported by computational models suggest that auxin may fulfil this role by regulating its own transport, but the plausibility of previously proposed models has been questioned. We applied the notion of unidirectional fluxes and the formalism of Petri nets to show that the key modes of auxin-driven patterning-the formation of convergence points and the formation of canals-can be implemented by biochemically plausible networks, with the fluxes measured by dedicated tally molecules or by efflux and influx carriers themselves. Common elements of these networks include a positive feedback of auxin efflux on the allocation of membrane-bound auxin efflux carriers (PIN proteins), and a modulation of this allocation by auxin in the extracellular space. Auxin concentration in the extracellular space is the only information exchanged by the cells. Canalization patterns are produced when auxin efflux and influx act antagonistically: an increase in auxin influx or concentration in the extracellular space decreases the abundance of efflux carriers in the adjacent segment of the membrane. In contrast, convergence points emerge in networks in which auxin efflux and influx act synergistically. A change in a single reaction rate may result in a dynamic switch between these modes, suggesting plausible molecular implementations of coordinated patterning of organ initials and vascular strands predicted by the dual polarization theory.

  9. 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.

  10. 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.

  11. Wind-driven pyroelectric energy harvesting device

    Science.gov (United States)

    Xie, Mengying; Zabek, Daniel; Bowen, Chris; Abdelmageed, Mostafa; Arafa, Mustafa

    2016-12-01

    Pyroelectric materials have recently received attention for harvesting waste heat owing to their potential to convert temperature fluctuations into useful electrical energy. One of the main challenges in designing pyroelectric energy harvesters is to provide a means to induce a temporal heat variation in a pyroelectric material autonomously from a steady heat source. To address this issue, we propose a new form of wind-driven pyroelectric energy harvester, in which a propeller is set in rotational motion by an incoming wind stream. The speed of the propeller’s shaft is reduced by a gearbox to drive a slider-crank mechanism, in which a pyroelectric material is placed on the slider. Thermal cycling is obtained as the reciprocating slider moves the pyroelectric material across alternative hot and cold zones created by a stationary heat lamp and ambient temperature, respectively. The open-circuit voltage and closed-circuit current are investigated in the time domain at various wind speeds. The device was experimentally tested under wind speeds ranging from 1.1 to 1.6 m s-1 and charged an external 100 nF capacitor through a signal conditioning circuit to demonstrate its effectiveness for energy harvesting. Unlike conventional wind turbines, the energy harvested by the pyroelectric material is decoupled from the wind flow and no mechanical power is drawn from the transmission; hence the system can operate at low wind speeds (<2 m s-1).

  12. Driven topological systems in the classical limit

    Science.gov (United States)

    Duncan, Callum W.; Öhberg, Patrik; Valiente, Manuel

    2017-03-01

    Periodically driven quantum systems can exhibit topologically nontrivial behavior, even when their quasienergy bands have zero Chern numbers. Much work has been conducted on noninteracting quantum-mechanical models where this kind of behavior is present. However, the inclusion of interactions in out-of-equilibrium quantum systems can prove to be quite challenging. On the other hand, the classical counterpart of hard-core interactions can be simulated efficiently via constrained random walks. The noninteracting model, proposed by Rudner et al. [Phys. Rev. X 3, 031005 (2013), 10.1103/PhysRevX.3.031005], has a special point for which the system is equivalent to a classical random walk. We consider the classical counterpart of this model, which is exact at a special point even when hard-core interactions are present, and show how these quantitatively affect the edge currents in a strip geometry. We find that the interacting classical system is well described by a mean-field theory. Using this we simulate the dynamics of the classical system, which show that the interactions play the role of Markovian, or time-dependent disorder. By comparing the evolution of classical and quantum edge currents in small lattices, we find regimes where the classical limit considered gives good insight into the quantum problem.

  13. 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)...

  14. 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...

  15. Nucleosynthesis in Magnetically Driven Jets from Collapsars

    CERN Document Server

    Fujimoto, Shin-ichiro; Hashimoto, Masa-aki

    2008-01-01

    We have made detailed calculations of the composition of magnetically driven jets ejected from collapsars, or rapidly rotating massive stars, based on long-term magnetohydrodynamic simulations of their core collapse with various distributions of magnetic field and angular momentum before collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase and through the jet generation phase using a large nuclear reaction network. We find that the r-process successfully operates only in energetic jets (> 1e51 ergs), such that U and Th are synthesized abundantly, even when the collapsar has a relatively weak magnetic field (1e10 G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to those of the r-elements in the solar system. About 0.01-0.06 Msun neutron-rich, heavy nuclei are ejected from a collapsar with energetic jets. The higher energy jets have larger amounts of Ni56, varying from 0.00037 to 0.06Msun...

  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. 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.

  18. Resource-Driven Scheduling Implementation in Malaysian Construction Industry

    Directory of Open Access Journals (Sweden)

    Aftab Hameed Memon

    2011-07-01

    Full Text Available Resource-driven scheduling techniques focus on resource. Their objective is to schedule activities so that a project dead line is met using predefined resource availability limits. This paper reports about the status of resource-driven scheduling implementation in Malaysian construction industry. An investigation Survey was conducted to determine the level of resource-driven scheduling and factors affecting the concerned implementation. Construction Firm registered under G7 (A Class, G6 (B class and G5 (C class were used in investigation. Data was analyzed by Statistical package SPSS to find the means and rank. Average index method was adapted to for the level of features of resource scheduling implementation and barrier to resource-driven scheduling. It is significant 59.65% firms are implementing resource-driven scheduling as partial. Also methods of project scheduling and resource options adopted were investigated. A Significant majority of construction firms (approximately 65% adopt Microsoft project for scheduling. Study showed that the features of resource scheduling are being implemented at Medium Level. Lack of understanding / awareness of concepts, lack of genuine commitment, lack of coordination of key personnel and Lack of coordination of constructors consultants were found major factors that affect resource-driven scheduling. While, expensive to prepare is most contributing factor, no enforcement on schedules from authority, difficult to prepare and hurdles by personnel/authorities were found as major constraints in implementing resource driven scheduling.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. An Instability-driven Dynamo for $\\gamma$ Ray Bursts

    CERN Document Server

    Araya-Gochez, R A

    2000-01-01

    We show that an MHD-instability driven dynamo (IDD) operating in a hot accretion disk is capable of generating energetically adequate magnetic flux deposition rates above and below a mildly advective accretion disk structure. The dynamo is driven by the magnetorotational instability (MRI) of a toroidal field in a shear flow and is limited by the buoyancy of `horizontal' flux and by reconnection in the turbulent medium. The efficiency of magnetic energy deposition is estimated to be comparable to the neutrino losses although an MHD collimation mechanism may deem this process a more viable alternative to neutrino-burst-driven models of gamma ray bursts.

  5. 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

  6. 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

  7. Dynamic Systems Driven by Non-Poissonian Impulses

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Iwankiewicz, R.

    Dynamic systems under random trains of impulses driven by renewal point processes are studied. Then the system state variables no longer form a Markov vector as it is in the case of Poisson impulses. A general format is given for the replacing an ordinary renewal process by an equivalent Poisson...... is developed for modelling it, via suitable choice of parameters, with the help of a Poisson driven process. The theory is illustrated for a Duffing oscillator under the impulses driven by the generalized Erlang process of the order k=2approximating an original renewal process with a lognormally distributed...

  8. 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.

  9. 76 FR 3604 - Information Collection; Qualified Products List for Engine Driven Pumps

    Science.gov (United States)

    2011-01-20

    ... Forest Service Information Collection; Qualified Products List for Engine Driven Pumps AGENCY: Forest... on the new information collection, Qualified Products List for Engine Driven Pumps. DATES: Comments.... SUPPLEMENTARY INFORMATION: Title: Qualified Products List for Engine Driven Pumps. OMB Number:...

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Efficiency of Wave-Driven Rigid Body Rotation Toroidal Confinement

    CERN Document Server

    Rax, J -M; Fisch, N J

    2016-01-01

    The compensation of vertical drifts in toroidal magnetic fields through a wave-driven poloidal rotation is compared to compensation through the wave driven toroidal current generation to support the classical magnetic rotational transform. The advantages and drawbacks associated with the sustainment of a radial electric field are compared with those associated with the sustainment of a poloidal magnetic field both in terms of energy content and power dissipation. The energy content of a radial electric field is found to be smaller than the energy content of a poloidal magnetic field for a similar set of orbits. The wave driven radial electric field generation efficiency is similarly shown, at least in the limit of large aspect ratio, to be larger than the efficiency of wave-driven toroidal current generation.

  18. Plasmon-driven sequential chemical reactions in an aqueous environment.

    Science.gov (United States)

    Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

    2014-06-24

    Plasmon-driven sequential chemical reactions were successfully realized in an aqueous environment. In an electrochemical environment, sequential chemical reactions were driven by an applied potential and laser irradiation. Furthermore, the rate of the chemical reaction was controlled via pH, which provides indirect evidence that the hot electrons generated from plasmon decay play an important role in plasmon-driven chemical reactions. In acidic conditions, the hot electrons were captured by the abundant H(+) in the aqueous environment, which prevented the chemical reaction. The developed plasmon-driven chemical reactions in an aqueous environment will significantly expand the applications of plasmon chemistry and may provide a promising avenue for green chemistry using plasmon catalysis in aqueous environments under irradiation by sunlight.

  19. Tongue-Driven Wheelchair Out-Maneuvers the Competition

    Science.gov (United States)

    ... 496-3500 Share Science Highlight: January 2, 2014 Tongue-Driven Wheelchair Out-Maneuvers the Competition Researchers funded ... Imaging and Bioengineering have demonstrated that their novel Tongue Drive System is superior to other assistive devices ...

  20. 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...

  1. 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

  2. Entropic Fluctuations in Thermally Driven Harmonic Networks

    Science.gov (United States)

    Jakšić, V.; Pillet, C.-A.; Shirikyan, A.

    2017-02-01

    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 S^t which satisfies the Gallavotti-Cohen fluctuation theorem. More precisely, we prove that there exists κ _c>1/2 such that the cumulant generating function of S^t has a large-time limit e(α ) which is finite on a closed interval [1/2-κ _c,1/2+κ _c], infinite on its complement and satisfies the Gallavotti-Cohen symmetry e(1-α )=e(α ) for all α in R. Moreover, we show that e(α ) is essentially smooth, i.e., that e'(α )→ ∓ ∞ as α → 1/2 ∓ κ _c. It follows from the Gärtner-Ellis theorem that S^t satisfies a global large deviation principle with a rate function I( s) obeying the Gallavotti-Cohen fluctuation relation I(-s)-I(s)=s for all sin R. We also consider perturbations of S^t 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 family of algebraic matrix Riccati equations. It turns out that the limiting cumulant generating functions of S^t and its perturbations can be computed in terms of spectral data of a Hamiltonian matrix depending on the harmonic potential of the network and the parameters of the Langevin reservoirs. This approach is well adapted to both analytical and numerical investigations.

  3. Entropic Fluctuations in Thermally Driven Harmonic Networks

    Science.gov (United States)

    Jakšić, V.; Pillet, C.-A.; Shirikyan, A.

    2016-10-01

    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 S^t which satisfies the Gallavotti-Cohen fluctuation theorem. More precisely, we prove that there exists κ_c>1/2 such that the cumulant generating function of S^t has a large-time limit e(&alpha) which is finite on a closed interval [1/2-κ_c,1/2+κ_c] , infinite on its complement and satisfies the Gallavotti-Cohen symmetry e(1-&alpha)=e(&alpha) for all α in R. Moreover, we show that e(&alpha) is essentially smooth, i.e., that e'(&alpha)→ ∓ ∞ as α → {1}/{2}∓ κ_c . It follows from the Gärtner-Ellis theorem that S^t satisfies a global large deviation principle with a rate function I(s) obeying the Gallavotti-Cohen fluctuation relation I(-s)-I(s)=s for all sin R. We also consider perturbations of S^t 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 family of algebraic matrix Riccati equations. It turns out that the limiting cumulant generating functions of S^t and its perturbations can be computed in terms of spectral data of a Hamiltonian matrix depending on the harmonic potential of the network and the parameters of the Langevin reservoirs. This approach is well adapted to both analytical and numerical investigations.

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

    OpenAIRE

    Azanza Sesé, Maider

    2011-01-01

    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...

  5. A Table-top Blast Driven Shock Tube

    OpenAIRE

    Courtney, Michael; Courtney, Amy

    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 d...

  6. 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....

  7. Pedagogical Evaluation of a Domain-Driven\\ud Design Framework

    OpenAIRE

    Wade, Steve; Salahat, Mohammed

    2012-01-01

    This paper presents a pedagogical evaluation of the framework SDDD (Soft Domain Driven Design) which encourages a “soft systems” approach to Domain-Driven Design. The framework combines techniques from Soft Systems Methodology (SSM) with notation from the Unified Modeling Language (UML) and the “Naked Objects” implementation pattern. The framework has been used in the delivery of a postgraduate module in Information Systems Design for a number of years. This paper reports on the way in which ...

  8. Remodelling fashion via circular economy driven luxury concept

    OpenAIRE

    Kuivanen, Pyry

    2016-01-01

    The thesis aimed to research circular economy’s intangible value in the global textile industry. The focus targeted on investigating, how luxury could become a positive input to a circular economy driven brand. The goal was to find and understand different perceptions of business concepts, customers and brands in order to build a notion of circular economy driven luxury fashion brand identity. Brand identity study was conducted by analyzing brands’ identities key facets. Scrutinizing mult...

  9. 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 $\

  10. 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

  11. Concerning the Feasibility of Example-driven Modelling Techniques

    OpenAIRE

    Thorne, Simon; Ball, David; Lawson, Zoe Frances

    2008-01-01

    We report on a series of experiments concerning the feasibility of example driven \\ud modelling. The main aim was to establish experimentally within an academic \\ud environment; the relationship between error and task complexity using a) Traditional \\ud spreadsheet modelling, b) example driven techniques. We report on the experimental \\ud design, sampling, research methods and the tasks set for both control and treatment \\ud groups. Analysis of the completed tasks allows comparison of several...

  12. 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...

  13. Domain-Driven Security : Injection & Cross-site scripting

    OpenAIRE

    Stendahl, Jonas

    2016-01-01

    Many web applications are vulnerable to Injection and Cross-site scripting. These attacks are often focused on infrastructural parts of the application. This thesis investigates if Domain-Driven Design can unify existing technical protection mechanisms as well as provide protection for attacks aimed at the business logic of an application. The performance of data validation and transformation performed with components from Domain-Driven Design is evaluated. The evaluation is performed by expo...

  14. Performance of Gas-Engine Driven Heat Pump Unit

    Energy Technology Data Exchange (ETDEWEB)

    Abdi Zaltash; Randy Linkous; Randall Wetherington; Patrick Geoghegan; Ed Vineyard; Isaac Mahderekal; Robert Gaylord

    2008-09-30

    Air-conditioning (cooling) for buildings is the single largest use of electricity in the United States (U.S.). This drives summer peak electric demand in much of the U.S. Improved air-conditioning technology thus has the greatest potential impact on the electric grid compared to other technologies that use electricity. Thermally-activated technologies (TAT), such as natural gas engine-driven heat pumps (GHP), can provide overall peak load reduction and electric grid relief for summer peak demand. GHP offers an attractive opportunity for commercial building owners to reduce electric demand charges and operating expenses. Engine-driven systems have several potential advantages over conventional single-speed or single-capacity electric motor-driven units. Among them are variable speed operation, high part load efficiency, high temperature waste heat recovery from the engine, and reduced annual operating costs (SCGC 1998). Although gas engine-driven systems have been in use since the 1960s, current research is resulting in better performance, lower maintenance requirements, and longer operating lifetimes. Gas engine-driven systems are typically more expensive to purchase than comparable electric motor-driven systems, but they typically cost less to operate, especially for commercial building applications. Operating cost savings for commercial applications are primarily driven by electric demand charges. GHP operating costs are dominated by fuel costs, but also include maintenance costs. The reliability of gas cooling equipment has improved in the last few years and maintenance requirements have decreased (SCGC 1998, Yahagi et al. 2006). Another advantage of the GHP over electric motor-driven is the ability to use the heat rejected from the engine during heating operation. The recovered heat can be used to supplement the vapor compression cycle during heating or to supply other process loads, such as water heating. The use of the engine waste heat results in greater

  15. 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

  16. Rigorous buoyancy driven bubble mixing for centrifugal microfluidics.

    Science.gov (United States)

    Burger, S; Schulz, M; von Stetten, F; Zengerle, R; Paust, N

    2016-01-21

    We present batch-mode mixing for centrifugal microfluidics operated at fixed rotational frequency. Gas is generated by the disk integrated decomposition of hydrogen peroxide (H2O2) to liquid water (H2O) and gaseous oxygen (O2) and inserted into a mixing chamber. There, bubbles are formed that ascent through the liquid in the artificial gravity field and lead to drag flow. Additionaly, strong buoyancy causes deformation and rupture of the gas bubbles and induces strong mixing flows in the liquids. Buoyancy driven bubble mixing is quantitatively compared to shake mode mixing, mixing by reciprocation and vortex mixing. To determine mixing efficiencies in a meaningful way, the different mixers are employed for mixing of a lysis reagent and human whole blood. Subsequently, DNA is extracted from the lysate and the amount of DNA recovered is taken as a measure for mixing efficiency. Relative to standard vortex mixing, DNA extraction based on buoyancy driven bubble mixing resulted in yields of 92 ± 8% (100 s mixing time) and 100 ± 8% (600 s) at 130g centrifugal acceleration. Shake mode mixing yields 96 ± 11% and is thus equal to buoyancy driven bubble mixing. An advantage of buoyancy driven bubble mixing is that it can be operated at fixed rotational frequency, however. The additional costs of implementing buoyancy driven bubble mixing are low since both the activation liquid and the catalyst are very low cost and no external means are required in the processing device. Furthermore, buoyancy driven bubble mixing can easily be integrated in a monolithic manner and is compatible to scalable manufacturing technologies such as injection moulding or thermoforming. We consider buoyancy driven bubble mixing an excellent alternative to shake mode mixing, in particular if the processing device is not capable of providing fast changes of rotational frequency or if the low average rotational frequency is challenging for the other integrated fluidic operations.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. Interfacial waves generated by electrowetting-driven contact line motion

    Science.gov (United States)

    Ha, Jonghyun; Park, Jaebum; Kim, Yunhee; Shin, Bongsu; Bae, Jungmok; Kim, Ho-Young

    2016-10-01

    The contact angle of a liquid-fluid interface can be effectively modulated by the electrowetting-on-dielectric (EWOD) technology. Rapid movement of the contact line can be achieved by swift changes of voltage at the electrodes, which can give rise to interfacial waves under the strong influence of surface tension. Here we experimentally demonstrate EWOD-driven interfacial waves of overlapping liquids and compare their wavelength and decay length with the theoretical results obtained by a perturbation analysis. Our theory also allows us to predict the temporal evolution of the interfacial profiles in either rectangular or cylindrical containers, as driven by slipping contact lines. This work builds a theoretical framework to understand and predict the dynamics of capillary waves of a liquid-liquid interface driven by EWOD, which has practical implications on optofluidic devices used to guide light.

  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. Torque Control of Underactuated Tendon-driven Robotic Fingers

    Science.gov (United States)

    Abdallah, Muhammad E. (Inventor); Ihrke, Chris A. (Inventor); Reiland, Matthew J. (Inventor); Wampler, Charles W. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Bridgwater, Lyndon (Inventor)

    2013-01-01

    A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

  7. 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...

  8. Replicate periodic windows in the parameter space of driven oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, E.S., E-mail: esm@if.usp.br [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil); Souza, S.L.T. de [Universidade Federal de Sao Joao del-Rei, Campus Alto Paraopeba, Minas Gerais (Brazil); Medrano-T, R.O. [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, Diadema, Sao Paulo (Brazil); Caldas, I.L. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)

    2011-11-15

    Highlights: > We apply a weak harmonic perturbation to control chaos in two driven oscillators. > We find replicate periodic windows in the driven oscillator parameter space. > We find that the periodic window replication is associated with the chaos control. - Abstract: In the bi-dimensional parameter space of driven oscillators, shrimp-shaped periodic windows are immersed in chaotic regions. For two of these oscillators, namely, Duffing and Josephson junction, we show that a weak harmonic perturbation replicates these periodic windows giving rise to parameter regions correspondent to periodic orbits. The new windows are composed of parameters whose periodic orbits have the same periodicity and pattern of stable and unstable periodic orbits already existent for the unperturbed oscillator. Moreover, these unstable periodic orbits are embedded in chaotic attractors in phase space regions where the new stable orbits are identified. Thus, the observed periodic window replication is an effective oscillator control process, once chaotic orbits are replaced by regular ones.

  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. Temporal Data-Driven Sleep Scheduling and Spatial Data-Driven Anomaly Detection for Clustered Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Gang Li

    2016-09-01

    Full Text Available The spatial–temporal correlation is an important feature of sensor data in wireless sensor networks (WSNs. Most of the existing works based on the spatial–temporal correlation can be divided into two parts: redundancy reduction and anomaly detection. These two parts are pursued separately in existing works. In this work, the combination of temporal data-driven sleep scheduling (TDSS and spatial data-driven anomaly detection is proposed, where TDSS can reduce data redundancy. The TDSS model is inspired by transmission control protocol (TCP congestion control. Based on long and linear cluster structure in the tunnel monitoring system, cooperative TDSS and spatial data-driven anomaly detection are then proposed. To realize synchronous acquisition in the same ring for analyzing the situation of every ring, TDSS is implemented in a cooperative way in the cluster. To keep the precision of sensor data, spatial data-driven anomaly detection based on the spatial correlation and Kriging method is realized to generate an anomaly indicator. The experiment results show that cooperative TDSS can realize non-uniform sensing effectively to reduce the energy consumption. In addition, spatial data-driven anomaly detection is quite significant for maintaining and improving the precision of sensor data.

  11. 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.

  12. A 300 Hz high frequency thermoacoustically driven pulse tube cooler

    Institute of Scientific and Technical Information of China (English)

    ZHU ShangLong; YU GuoYao; ZHANG XiaoDong; DAI Wei; LUO ErCang; ZHOU Yuan

    2008-01-01

    This article introduces the latest progress of a 300 Hz thermoacoustically driven pulse tube cooler. Based on the experience of former experiments, improvements have been made in the standing-wave engine, pulse tube cooler and their coupling mechanism. An inlet pressure ratio of 1.248 was obtained with the mean pressure and heating power of 4.13 MPa and 1760 W, respectively. A lowest no-load temperature of 69.5 K has been reached under this condition. This is the first time for thermoacousti-cally driven pulse tube coolers to reach the temperature below 76 K with such a high frequency.

  13. Superfluid stiffness of a driven dissipative condensate with disorder.

    Science.gov (United States)

    Janot, Alexander; Hyart, Timo; Eastham, Paul R; Rosenow, Bernd

    2013-12-01

    Observations of macroscopic quantum coherence in driven systems, e.g. polariton condensates, have strongly stimulated experimental as well as theoretical efforts during the last decade. We address the question of whether a driven quantum condensate is a superfluid, allowing for the effects of disorder and its nonequilibrium nature. We predict that for spatial dimensions d<4 the superfluid stiffness vanishes once the condensate exceeds a critical size, and treat in detail the case d=2. Thus a nonequilibrium condensate is not a superfluid in the thermodynamic limit, even for weak disorder, although superfluid behavior would persist in small systems.

  14. 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.

  15. 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.

  16. On the drift kinetic equation driven by plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Shaing, K C [Plasma and Space Science Center and ISAPS, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Engineering Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2010-07-15

    A drift kinetic equation that is driven by plasma flows has previously been derived by Shaing and Spong 1990 (Phys. Fluids B 2 1190). The terms that are driven by particle speed that is parallel to the magnetic field B have been neglected. Here, such terms are discussed to examine their importance to the equation and to show that these terms do not contribute to the calculations of plasma viscosity in large aspect ratio toroidal plasmas, e.g. tokamaks and stellarators. (brief communication)

  17. Tendon-driven manipulators: Analysis, synthesis, and control

    Science.gov (United States)

    Lee, Jyh-Jone

    As the development of light-weight, small volume, and versatile manipulators has grown in the field of robotics, the need for more efficient and relevant power transmission systems in the manipulators has become increasingly apparent. It is clear that the advent of efficient, low friction, and backlash-free actuation systems promises to provide significant gains in manipulator performance. Tendon transmission has been widely used to actuate small volume and light-weight articulated manipulators, such as dextrous mechanical hands, for it permits actuators to be installed remotely from the end-effector, thus reducing the bulk and inertia of the manipulator system. Current research on such actuation systems is accomplished on the basis of specialized designs. The lack of systematic approaches has limited our scope in realizing performance of such transmission systems. Therefore, when associated with systematic methodologies, the study of tendon-driven manipulators promises to be of major importance in the field of robotics. This dissertation is concerned with four issues to enhance our use and understanding of tendon-driven manipulators. First, a systematic approach for the kinematics analysis of tendon-driven manipulators is established. A graph is used to represent the kinematic structure of tendon-driven manipulators. It is shown that the kinematic structure of tendon-driven manipulators is in every way similar to that of epicyclic gear trains. The fundamental circuit equation developed for the kinematic analysis of epicyclic gear trains can thus be applied to this type of mechanism. The displacement equation governing joint angle space and tendon space can easily be obtained. Secondly, the concept of structural isomorphism and the structural characteristics of tendon-driven manipulators are investigated. Based on the explored properties, a methodology for the enumeration of tendon-driven manipulators is developed. By applying the methodology, a class of kinematic

  18. Filamentation instability of counter-streaming laser-driven plasmas

    CERN Document Server

    Fox, W; Bhattacharjee, A; Chang, P -Y; Germaschewski, K; Hu, S X; Nilson, P M

    2013-01-01

    Filamentation due to the growth of a Weibel-type instability was observed in the interaction of a pair of counter-streaming, ablatively-driven plasma flows, in a supersonic, collisionless regime relevant to astrophysical collisionless shocks. The flows were created by irradiating a pair of opposing plastic (CH) foils with 1.8 kJ, 2-ns laser pulses on the OMEGA EP laser system. Ultrafast laser-driven proton radiography was used to image the Weibel-generated electromagnetic fields. The experimental observations are in good agreement with the analytical theory of the Weibel instability and with particle-in-cell simulations.

  19. 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.

  20. 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

  1. Patron-Driven Acquisition (PDA - ein Modell mit Zukunft?

    Directory of Open Access Journals (Sweden)

    Rainer Plappert

    2015-12-01

    Full Text Available Gestützt auf eine dreijährige Erfahrung mit der nutzergesteuerten Erwerbung an der UB Erlangen-Nürnberg beleuchtet der Beitrag die verschiedenen Rollen der an dieser Erwerbungsform beteiligten Akteure. Vor dem Hintergrund geänderter Geschäftsmodelle werden die zukünftigen Perspektiven der nutzergesteuerten Erwerbung in Deutschland kritisch hinterfragt. Based on a three years experience with Patron-Driven Acquisition at University library Erlangen-Nuremberg the article discusses the roles of the protagonists at this acquisition form. Regarding to modified business models the perspectives of Patron-Driven Acquision in Germany seems to be unconfident.

  2. Patterns, principles, and practices of domain-driven design

    CERN Document Server

    Millett, Scott

    2015-01-01

    Methods for managing complex software construction following the practices, principles and patterns of Domain-Driven Design with code examples in C# This book presents the philosophy of Domain-Driven Design (DDD) in a down-to-earth and practical manner for experienced developers building applications for complex domains. A focus is placed on the principles and practices of decomposing a complex problem space as well as the implementation patterns and best practices for shaping a maintainable solution space. You will learn how to build effective domain models through the use of tactical pat

  3. Rpr- and hid-driven cell death in Drosophila photoreceptors.

    Science.gov (United States)

    Hsu, Cheng Da; Adams, Sheila M; O'Tousa, Joseph E

    2002-02-01

    The reaper (rpr) and head involution defective (hid) genes mediate programmed cell death (PCD) during Drosophila development. We show that expression of either rpr or hid under control of a rhodopsin promoter induces rapid cell death of adult photoreceptor cells. Ultrastructural analysis revealed that the dying photoreceptor cells share morphological features with other cells undergoing PCD. The anti-apoptotic baculoviral P35 protein acts downstream of hid activity to suppress the photoreceptor cell death driven by rpr and hid. These results establish that the Drosophila photoreceptors are sensitive to the rpr- and hid-driven cell death pathways.

  4. Filamentation Instability of Counterstreaming Laser-Driven Plasmas

    Science.gov (United States)

    Fox, W.; Fiksel, G.; Bhattacharjee, A.; Chang, P.-Y.; Germaschewski, K.; Hu, S. X.; Nilson, P. M.

    2013-11-01

    Filamentation due to the growth of a Weibel-type instability was observed in the interaction of a pair of counterstreaming, ablatively driven plasma flows, in a supersonic, collisionless regime relevant to astrophysical collisionless shocks. The flows were created by irradiating a pair of opposing plastic (CH) foils with 1.8 kJ, 2-ns laser pulses on the OMEGA EP Laser System. Ultrafast laser-driven proton radiography was used to image the Weibel-generated electromagnetic fields. The experimental observations are in good agreement with the analytical theory of the Weibel instability and with particle-in-cell simulations.

  5. Toroidal equilibrium with low frequency wave driven currents

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.A.

    1984-12-01

    In the absence of an emf the parallel current, j/sub parallel/, in a steady state tokamak will consist of a neoclassical portion plus a wave-driven contribution. Using the drift kinetic equation, the quasilinear (wave-driven) current is computed for high phase speed waves in a torus, and this is combined with the neoclassical term to obtain the general expression for the flux surface average . For a given pressure profile this technique fully determines the MHD equilibrium, permitting the study of a new class of toroidal equilibria.

  6. Dynamic Data Driven Methods for Self-aware Aerospace Vehicles

    Science.gov (United States)

    2015-04-08

    AFRL-OSR-VA-TR-2015-0127 Dynamic Data Driven Methods for Self-aware Aerospace Vehicles Karen Willcox MASSACHUSETTS INSTITUTE OF TECHNOLOGY Final...Methods for Self-aware Aerospace Vehicles 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-11-1-0339 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Karen E...Back (Rev. 8/98) Dynamic Data Driven Methods for Self-aware Aerospace Vehicles Grant # FA9550-11-1-0339 Final Report Participating Institutions

  7. 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.

  8. Delay-induced driven patterns in coupled Cayley tree networks

    CERN Document Server

    Singh, Aradhana

    2013-01-01

    We study effects of delay in diffusively coupled logistic maps on the Cayley tree networks. We find that smaller coupling values exhibits sensitiveness for value of delay, and leads to different cluster patterns of self-organized and driven types. Whereas larger coupling strengths are very robust against change in delay values, and leads to stable driven clusters comprising only nodes from last generation of the Calaye tree. Furthermore, introduction of delay exhibits suppression as well as enhancement of synchronization depending upon coupling strength values, hence demonstrating richness of the model. To the end we relate the results with social conflicts and cooperation observed in families.

  9. A combined Event-Driven/Time-Driven molecular dynamics algorithm for the simulation of shock waves in rarefied gases

    Science.gov (United States)

    Valentini, Paolo; Schwartzentruber, Thomas E.

    2009-12-01

    A novel combined Event-Driven/Time-Driven (ED/TD) algorithm to speed-up the Molecular Dynamics simulation of rarefied gases using realistic spherically symmetric soft potentials is presented. Due to the low density regime, the proposed method correctly identifies the time that must elapse before the next interaction occurs, similarly to Event-Driven Molecular Dynamics. However, each interaction is treated using Time-Driven Molecular Dynamics, thereby integrating Newton's Second Law using the sufficiently small time step needed to correctly resolve the atomic motion. Although infrequent, many-body interactions are also accounted for with a small approximation. The combined ED/TD method is shown to correctly reproduce translational relaxation in argon, described using the Lennard-Jones potential. For densities between ρ=10-4 kg/m and ρ=10-1 kg/m, comparisons with kinetic theory, Direct Simulation Monte Carlo, and pure Time-Driven Molecular Dynamics demonstrate that the ED/TD algorithm correctly reproduces the proper collision rates and the evolution toward thermal equilibrium. Finally, the combined ED/TD algorithm is applied to the simulation of a Mach 9 shock wave in rarefied argon. Density and temperature profiles as well as molecular velocity distributions accurately match DSMC results, and the shock thickness is within the experimental uncertainty. For the problems considered, the ED/TD algorithm ranged from several hundred to several thousand times faster than conventional Time-Driven MD. Moreover, the force calculation to integrate the molecular trajectories is found to contribute a negligible amount to the overall ED/TD simulation time. Therefore, this method could pave the way for the application of much more refined and expensive interatomic potentials, either classical or first-principles, to Molecular Dynamics simulations of shock waves in rarefied gases, involving vibrational nonequilibrium and chemical reactivity.

  10. Behavioural Motives of Acquisition of Solar-driven Equipment

    Directory of Open Access Journals (Sweden)

    Shkurupska Iryna O.

    2013-12-01

    Full Text Available The article identifies needs of the target group, namely structure of motives, which justify making a decision to buy, in order to create efficient marketing strategy of an enterprise, which sell solar-driven equipment in Ukraine. There are five segments in the domestic market of helio-systems: individual consumers, recreation industry, agrarian industry, construction and social spheres. The article allocates 15 motives of acquisition of the solar-driven equipment for these segments, the most important of which are price, availability of solar energy, alternative price and energy saving. Besides, the structure of such motives is determined for each segment individually. In order to choose specific marketing instruments in the policy of promotion of solar-driven equipment, the article identifies differences in the form of goals of use and motives of acquisition between the specified consumer segments. The article reveals certain barriers that interfere with acquisition of solar-driven equipment – low level of trust into helio-systems, conservatism of consumers, absence of free applications for consumers – overcoming which is only possible with the help of certain marketing actions.

  11. Co-Constructing Knowledge through NGO-Driven Circle Work

    DEFF Research Database (Denmark)

    Agerbæk, Jonas

    This presentation revolves around the question of what degree of control, if any, the users participating in NGO-driven development programs may have over their own development. Based on a multi-sited ethnography of NGO organizing and communication that I conducted in the period of 2010 to 2015, ...

  12. Independent component analysis in non-hypothesis driven metabolomics

    DEFF Research Database (Denmark)

    Li, Xiang; Hansen, Jakob; Zhao, Xinjie

    2012-01-01

    In a non-hypothesis driven metabolomics approach plasma samples collected at six different time points (before, during and after an exercise bout) were analyzed by gas chromatography-time of flight mass spectrometry (GC-TOF MS). Since independent component analysis (ICA) does not need a priori...

  13. Concurrent Smalltalk on the Message-Driven Processor

    Science.gov (United States)

    1991-09-01

    NDPSim -x 2 -y 2 - maize Ox1O00 ::Coamoa:Coamoa.m NewFact.mdp Message-Driven Processor Simulator Version 7.0 Rev B Accompanies MDP Architecture Document...it could peel invocations of recursive functions forever. However, the sin- gle pass of inlining does not mean that functions are only inlined one

  14. Pilot implementation Driven by Effects Specifications and Formative Usability Evaluation

    DEFF Research Database (Denmark)

    Barlach, Anders; Hertzum, Morten; Simonsen, Jesper

    2013-01-01

    . The project was conducted using effects-driven IT development: a process comprised of workshops with specification of the usage effects by management and end-users followed by an agile development process progressing through mock-ups, prototypes and finally the pilot system. Effects were iteratively refined...

  15. Data Driven Decision Making in the Social Studies

    Science.gov (United States)

    Ediger, Marlow

    2010-01-01

    Data driven decision making emphasizes the importance of the teacher using objective sources of information in developing the social studies curriculum. Too frequently, decisions of teachers have been made based on routine and outdated methods of teaching. Valid and reliable tests used to secure results from pupil learning make for better…

  16. An Intuitive Formal Proof for Deadline Driven Scheduler

    Institute of Scientific and Technical Information of China (English)

    詹乃军

    2001-01-01

    This paper presents another formal proof for the correctness of the Deadline Driven Scheduler (DDS). This proof is given in terms of Duration Calculus which provides abstraction for random preemption of processor. Compared with other approaches, this proof relies on many intuitive facts. Therefore this proof is more intuitive, while it is still formal.

  17. Development of a ciliary muscle-driven accommodating intraocular lens

    NARCIS (Netherlands)

    Hermans, Erik A.; Terwee, Thom T.; Koopmans, Steven A.; Dubbelman, Michiel; van der Heijde, Rob G. L.; Heethaar, Rob M.

    2008-01-01

    PURPOSE: To develop a ciliary muscle-driven accommodating intraocular lens (IOL) that has a large and predictable range of variable power as a step toward spectacle independence. SETTING: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands. METHODS:

  18. Pilot evaluation in TENCompetence: a theory-driven model1

    NARCIS (Netherlands)

    J. Schoonenboom; H. Sligte; A. Moghnieh; M. Specht; C. Glahn; K. Stefanov

    2008-01-01

    This paper describes a theory-driven evaluation model that is used in evaluating four pilots in which an infrastructure for lifelong competence development, which is currently being developed, is validated. The model makes visible the separate implementation steps that connect the envisaged infrastr

  19. Towards model-driven evolvability of enterprise information systems

    NARCIS (Netherlands)

    Meijler, Theo Dirk; Postmus, Douwe; Wortmann, Hans

    2006-01-01

    Large scale integrated Enterprise Systems must constantly be adapted to changing circumstances in the enterprise. Thus applying small incremental changes is needed. This however requires powerful impact management of changes on dependent parts of a system. The Model Driven Architecture (MDA) is a pr

  20. Model-driven design, refinement and transformation of abstract interactions

    NARCIS (Netherlands)

    Almeida, João Paolo A.; Dijkman, Remco; Ferreira Pires, Luis; Quartel, Dick; Sinderen, van Marten

    2006-01-01

    In a model-driven design process the interaction between application parts can be described at various levels of platform-independence. At the lowest level of platform-independence, interaction is realized by interaction mechanisms provided by specific middleware platforms. At higher levels of platf

  1. Towards a Theory of Impasse-Driven Learning.

    Science.gov (United States)

    1987-02-12

    of learning theories where negative reinforcement of an internal kind causes a more-ar-less random change in the learner’s knowledge. Impasse-driven...learning is more specific than these theories in that it postulates exactly what kinds of negative reinforcement cause learning (i.e., impasses) and

  2. 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 differenc...

  3. Light-Driven Rotary Molecular Motors on Gold Nanoparticles

    NARCIS (Netherlands)

    Pollard, Michael M.; ter Wiel, Matthijs K. J.; van Delden, Richard A.; Vicario, Javier; Koumura, Nagatoshi; van den Brom, Coenraad R.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    We report the synthesis of unidirectional light-driven rotary molecular motors based oil chiral overcrowded alkenes and their immobilisation on the surface of gold nanoparticles through two anchors. Using a combination of (1)H and (13)C NMR, UV/Vis and CD spectroscopy, we show that these motors pres

  4. A Survey on Economic-driven Evaluations of Information Technology

    NARCIS (Netherlands)

    Mutschler, B.; Zarvić, N.; Reichert, M.U.

    2007-01-01

    The economic-driven evaluation of information technology (IT) has become an important instrument in the management of IT projects. Numerous approaches have been developed to quantify the costs of an IT investment and its assumed profit, to evaluate its impact on business process performance, and to

  5. The Dynamic test of Novel Punch Driven by Linear Motor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The key character of punch is its impulsion. For the novel punch driven by linear motor, the computer-aided test system is used. Its frequency performance is calculated by the identification method according to the dynamic demarcation. This dynamic test system presented here can be applied in the sample machines under development and performance test of finished products.

  6. Implosion of indirectly driven reentrant cone shell target

    Energy Technology Data Exchange (ETDEWEB)

    R.B. Stephens; S.P. Hatchett; R.E. Turner; K.A. Tanaka; R. Kodama

    2003-10-31

    In an x-ray driven reentrant cone fast ignition target the x-ray spectrum contains a high energy component that casuses preheating of the reentrant cone and mixing of the gold into the collapsing shell. Direct laser drive might avoid this problem.

  7. Evanescent states and nonequilibrium in driven superconducting nanowires

    NARCIS (Netherlands)

    Vercruyssen, N.; Verhagen, T.G.A.; Flokstra, M.G.; Pekola, J.P.; Klapwijk, T.M.

    2012-01-01

    We study the nonlinear response of current transport in a superconducting diffusive nanowire between normal reservoirs. We demonstrate theoretically and experimentally the existence of two different superconducting states appearing when the wire is driven out of equilibrium by an applied bias, calle

  8. Employee-driven innovation in large project organisations

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Wandahl, Søren; Christensen, Randi Muff

    2014-01-01

    In the built environment there is considered to be a great potential for innovation and continuous improvement based on the employees’ tacit as well as spoken knowledge. Through a case study the aim of this research was to challenge the theoretical approach to conduct employee-driven innovation...

  9. Business-driven innovations towards more sustainable chemical products

    NARCIS (Netherlands)

    Visser, R.; Jongen, M.; Zwetsloot, G.

    2008-01-01

    The aim of the study presented here was to gain an understanding of business-driven innovations towards more sustainable chemical products and processes. A case study was undertaken to assess and analyse the experiences of five different companies. These companies varied in size from small to a mult

  10. Data mining, knowledge discovery and data-driven modelling

    NARCIS (Netherlands)

    Solomatine, D.P.; Velickov, S.; Bhattacharya, B.; Van der Wal, B.

    2003-01-01

    The project was aimed at exploring the possibilities of a new paradigm in modelling - data-driven modelling, often referred as "data mining". Several application areas were considered: sedimentation problems in the Port of Rotterdam, automatic soil classification on the basis of cone penetration tes

  11. Photo-driven Molecular Wankel Engine B$_{13}^+$

    CERN Document Server

    Zhang, Jin; Sparta, Manuel; Alexandrova, Anastassia N

    2012-01-01

    We report a molecular Wankel motor, the dual-ring structure B13+, driven by circularly-polarized infrared electromagnetic radiation, under which a guided uni-directional rotation of the outer ring is achieved with rotational frequency of the order of 300 MHz.

  12. Light-driven rotary molecular motors : an ultrafast optical study

    NARCIS (Netherlands)

    Augulis, Ramunas; Klok, Martin; Loosdrecht, Paul H.M. van; Feringa, Bernard

    2009-01-01

    Molecular rotary motors, though common in nature, were first synthesized rather recently. One of the most promising categories of light-driven rotary molecular motors which allow for optical control is based on helical overcrowded alkenes. In this category of motors, the rotation of the motor’s roto

  13. Critical Path Driven Cosynthesis for Heterogeneous Target Architectures

    DEFF Research Database (Denmark)

    Bjørn-Jørgensen, Peter; Madsen, Jan

    1997-01-01

    This paper presents a critical path driven algorithm to produce a static schedule of a single-rate system onto a heterogeneous target architecture. Our algorithm is a list based scheduling algorithm which concurrently assigns tasks to processors and allocates nets to interprocessor communication....

  14. The operational mechanism of ferroelectric-driven organic resistive switches

    NARCIS (Netherlands)

    Kemerink, M.; Asadi, K.; Blom, P.W.M.; Leeuw, D.M. de

    2012-01-01

    The availability of a reliable memory element is crucial for the fabrication of 'plastic' logic circuits. We use numerical simulations to show that the switching mechanism of ferroelectric-driven organic resistive switches is the stray field of the polarized ferroelectric phase. The stray field modu

  15. Towards a conceptual framework for Experience-Driven Innovation

    NARCIS (Netherlands)

    Schifferstein, H.N.J.; Kleinsmann, M.S.; Jepma, E.J.

    2012-01-01

    Companies that aim to evoke specific experiences among their customers, should not only modify their design process, but also need to reorganize their innovation processes. Experience-driven innovation has implications on at least three levels in the organization: company, brand, and product/service

  16. Gravity-driven thickening in a long, vertical tube

    NARCIS (Netherlands)

    Meetsma, W.A.; Hoffmann, A.C; Cox, E.L.

    1996-01-01

    The problem of gravity-driven thickening of a dispersion in a long, vertical tube of diameter larger than the dimensions of the dispersed phase particles has been treated. Inflow of the suspension takes place through the porous tube wall and suspension is pumped away both at the upper and lower ends

  17. Driven translocation of a polymer: Fluctuations at work

    NARCIS (Netherlands)

    Dubbeldam, J.L.A.; Rostiashvii, V.G.; Milchev, A.; Vilgis, T.A.

    2013-01-01

    The impact of thermal fluctuations on the translocation dynamics of a polymer chain driven through a narrow pore has been investigated theoretically and by means of extensive molecular dynamics (MD) simulation. The theoretical consideration is based on the so-called velocity Langevin (V-Langevin) eq

  18. Mechanics of Interrill Erosion with Wind-Driven Rain (WDR)

    Science.gov (United States)

    This article provides an evaluation analysis for the performance of the interrill component of the Water Erosion Prediction Project (WEPP) model for Wind-Driven Rain (WDR) events. The interrill delivery rates (Di) were collected in the wind tunnel rainfall simulator facility of the International Cen...

  19. Mechanics of interrill erosion with wind-driven rain

    Science.gov (United States)

    The vector physics of wind-driven rain (WDR) differs from that of wind-free rain, and the interrill soil detachment equations in the Water Erosion Prediction Project (WEPP) model were not originally developed to deal with this phenomenon. This article provides an evaluation of the performance of the...

  20. Contract Driven Creation and Operation of Virtual Enterprises

    NARCIS (Netherlands)

    Hoffner, Yigal; Field, Simon; Grefen, Paul; Ludwig, Heiko

    2001-01-01

    This paper examines the support needed for dynamically creating and managing contract-driven virtual enterprises. Our approach to virtual enterprises views contracts as the central theme that runs throughout the enterprises' life cycle and touches upon all major aspects thereof. A Contract Framework