Summary of 2016 Light Microscopy Module (LMM) Physical Science Experiments on ISS. Update of LMM Science Experiments and Facility Capabilities

NASA Technical Reports Server (NTRS)

Sicker, Ronald J.; Meyer, William V.; Foster, William M.; Fletcher, William A.; Williams, Stuart J.; Lee, Chang-Soo

2016-01-01

This presentation will feature a series of short, entertaining, and informative videos that describe the current status and science support for the Light Microscopy Module (LMM) facility on the International Space Station. These interviews will focus on current experiments and provide an overview of future capabilities. The recently completed experiments include nano-particle haloing, 3-D self-assembly with Janus particles and a model system for nano-particle drug delivery. The videos will share perspectives from the scientists, engineers, and managers working with the NASA Light Microscopy program.

A New Perspective on Trapped Radiation Belts in Planetary Atmospheres

NASA Technical Reports Server (NTRS)

Diaz, A.; Lodhi, M. A. K.; Wilson, T. L.

2005-01-01

The charged particle fluxes trapped in the magnetic dipole fields of certain planets in our Solar System are interesting signatures of planetary properties in space physics. They also represent a source of potentially hazardous radiation to spacecraft during planetary and interplanetary exploration. The Earth s trapped radiation belts have been studied for years and the physical mechanisms by which primary radiation from the Sun and Galaxy is captured is well understood. The higher-energy particles collide with molecules in the planetary atmosphere and initiate large cascades of secondary radiation which itself becomes trapped by the magnetic dipole field of the planet. Some of it is even backscattered as albedo neutrons.

Status and perspectives of neutrino physics at present and future experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pagliarone, Carmine Elvezio, E-mail: pagliarone@unicas.it, E-mail: carmine.pagliarone@lngs.infn.it; Laboratori Nazionali del Gran Sasso

2016-03-25

Neutrino Physics and Dark Matter searches play a crucial role in nowadays Particle and Astroparticle Physics. The present review paper will describe general properties of neutrinos and neutrino mass phenomenology (Dirac and Majorana masses). Space will be dedicated to the experimental attempts to answer the question of the neutrino mass hierarchy. We will give, then, a short review of the results of part of the experiments that have been running so far. We will also shortly summarize future experiments that plan to explore this very wide scientific area.

Quantum scattering beyond the plane-wave approximation

NASA Astrophysics Data System (ADS)

Karlovets, Dmitry

2017-12-01

While a plane-wave approximation in high-energy physics works well in a majority of practical cases, it becomes inapplicable for scattering of the vortex particles carrying orbital angular momentum, of Airy beams, of the so-called Schrödinger cat states, and their generalizations. Such quantum states of photons, electrons and neutrons have been generated experimentally in recent years, opening up new perspectives in quantum optics, electron microscopy, particle physics, and so forth. Here we discuss the non-plane-wave effects in scattering brought about by the novel quantum numbers of these wave packets. For the well-focused electrons of intermediate energies, already available at electron microscopes, the corresponding contribution can surpass that of the radiative corrections. Moreover, collisions of the cat-like superpositions of such focused beams with atoms allow one to probe effects of the quantum interference, which have never played any role in particle scattering.

Helicity and nuclear β decay correlations

NASA Astrophysics Data System (ADS)

Hong, Ran; Sternberg, Matthew G.; Garcia, Alejandro

2017-01-01

We present simple derivations of nuclear β-decay correlations with an emphasis on the special role of helicity. This topic provides a good opportunity to teach students about helicity and chirality in particle physics with exercises that use simple aspects of quantum mechanics. In addition, this paper serves as an introduction to nuclear β-decay correlations from both a theoretical and experimental perspective. This article can be used to introduce students to ongoing experiments searching for hints of new physics in the low-energy precision frontier.

Integration of active pharmaceutical ingredient solid form selection and particle engineering into drug product design.

PubMed

Ticehurst, Martyn David; Marziano, Ivan

2015-06-01

This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API) physical properties, their link to solid form selection and the role of particle engineering. While the crucial role of active pharmaceutical ingredient (API) solid form selection is universally acknowledged in the pharmaceutical industry, the value of increasing effort to understanding the link between solid form, API physical properties and drug product formulation and manufacture is now also being recognised. A truly holistic strategy for drug product development should focus on connecting solid form selection, particle engineering and formulation design to both exploit opportunities to access simpler manufacturing operations and prevent failures. Modelling and predictive tools that assist in establishing these links early in product development are discussed. In addition, the potential for differences between the ingoing API physical properties and those in the final product caused by drug product processing is considered. The focus of this review is on oral solid dosage forms and dry powder inhaler products for lung delivery. © 2015 Royal Pharmaceutical Society.

Particle Sorting and Motility Out of Equilibrium

NASA Astrophysics Data System (ADS)

Sandford, Cato

The theory of equilibrium statistical physics, formulated over a century ago, provides an excellent description of physical systems which have reached a static, relaxed state. Such systems can be loosely thought of as maximally disordered, in keeping with the Second Law of Thermodynamics which states that a thermal system in equilibrium has reached a state of highest entropy. However, many entities in the world around us maintain themselves in an remarkably ordered and dynamic state, and must pay for this by producing entropy in their surroundings. Organisms, for example, convert chemical energy (food) into heat, which is then dumped into the environment, raising its entropy. Systems which produce entropy through any mechanism must be described by theories of non-equilibrium statistical physics, for which there currently exists no unified framework or ontology. Here we examine two specific cases of non-equilibrium phenomena from a theoretical perspective. First, we explore the behaviour of microscopic particles which continually dissipate energy to propel themselves through their environment. Second, we consider how devices which distinguish between different types of particles can exploit non-equilibrium processes to enhance their performance. For the case of self-propelled particles, we consider a theoretical model where the particle's propulsion force has "memory"--it is a random process whose instantaneous value depends on its past evolution. This introduces a persistence in the particle's motion, and requires the dissipation of energy into its surroundings. These particles are found to exhibit a variety of behaviours forbidden in equilibrium systems: for instance they may cluster around barriers, exert unbalanced forces, and sustain steady flows through space. We develop the understanding of these particles' dynamics through a combination of explicit calculations, approximations and numerical simulation which characterise and quantify their non-equilibrium behaviour. The second situation investigated concerns the physics of particle-sorting, which is fundamental to biological systems. We introduce a number of model devices designed to distinguish between and segregate two species of particles, and analyse how the quality and speed of their operation may be influenced by providing them with an energy source which pushes them out of equilibrium. We identify different physical regimes, where our devices may consume energy to deliver better results or deliver them faster or both; and we furthermore connect the broader theory of particle sorting to the fundamental theoretical framework of statistical physics.

Physics perspectives of heavy-ion collisions at very high energy

DOE PAGES

Chang, Ning-bo; Cao, ShanShan; Chen, Bao-yi; ...

2016-01-15

We expect heavy-ion collisions at very high colliding energies to produce a quark-gluon plasma (QGP) at the highest temperature obtainable in a laboratory setting. Experimental studies of these reactions can provide an unprecedented range of information on properties of the QGP at high temperatures. We also report theoretical investigations of the physics perspectives of heavy-ion collisions at a future high-energy collider. These include initial parton production, collective expansion of the dense medium, jet quenching, heavy-quark transport, dissociation and regeneration of quarkonia, photon and dilepton production. Here, we illustrate the potential of future experimental studies of the initial particle production andmore » formation of QGP at the highest temperature to provide constraints on properties of strongly interaction matter.« less

Solar Polar Imager: Observing Coronal Transients from a New Perspective (Invited)

NASA Astrophysics Data System (ADS)

Liewer, P. C.

2013-12-01

The heliophysics community has long recognized the need for a mission to observe the Sun and corona from a polar perspective. One mission concept, the Solar Polar Imager (SPI), has been studied extensively (Liewer et al in NASA Space Science Vision Missions, 2008). In this concept, a solar sail is used to place a spacecraft in a circular 0.48-AU heliocentric orbit with an inclination of ~75 degrees. This orbit enables crucial observations not possible from lower latitude perspectives. Magnetograph and Doppler observations from a polar vantage point would revolutionize our understanding of the mechanism of solar activity cycles, polar magnetic field reversals, the internal structure and dynamics of the Sun and its atmosphere. The rapid 4-month polar orbit combined with both in situ and remote sensing instrumentation further enables unprecedented studies of the physical connection between the Sun, the solar wind, and solar energetic particles. From the polar perspective, white light imagers could be used to track CMEs and predict their arrival at Earth (as demonstrated by STEREO). SPI is also well suited to study the relative roles of CME-driven shock versus flare-associated processes in solar energetic particle acceleration. With the circular 0.48 AU orbit, solar energetic particles could be more easily traced to their sources and their variation with latitude can be studied at a constant radius. This talk will discuss the science objectives, instrumentation and mission design for the SPI mission.

Do the repulsive and attractive pair forces play separate roles for the physics of liquids?

PubMed

Bøhling, Lasse; Veldhorst, Arno A; Ingebrigtsen, Trond S; Bailey, Nicholas P; Hansen, Jesper S; Toxvaerd, Søren; Schrøder, Thomas B; Dyre, Jeppe C

2013-01-23

According to standard liquid-state theory repulsive and attractive pair forces play distinct roles for the physics of liquids. This paradigm is put into perspective here by demonstrating a continuous series of pair potentials that have virtually the same structure and dynamics, although only some of them have attractive forces of significance. Our findings reflect the fact that the motion of a given particle is determined by the total force on it, whereas the quantity usually discussed in liquid-state theory is the individual pair force.

Exploring Flavor Physics with Lattice QCD

NASA Astrophysics Data System (ADS)

Du, Daping; Fermilab/MILC Collaborations Collaboration

2016-03-01

The Standard Model has been a very good description of the subatomic particle physics. In the search for physics beyond the Standard Model in the context of flavor physics, it is important to sharpen our probes using some gold-plated processes (such as B rare decays), which requires the knowledge of the input parameters, such as the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements and other nonperturbative quantities, with sufficient precision. Lattice QCD is so far the only first-principle method which could compute these quantities with competitive and systematically improvable precision using the state of the art simulation techniques. I will discuss the recent progress of lattice QCD calculations on some of these nonpurturbative quantities and their applications in flavor physics. I will also discuss the implications and future perspectives of these calculations in flavor physics.

Recent results and perspectives on cosmology and fundamental physics from microwave surveys

NASA Astrophysics Data System (ADS)

Burigana, Carlo; Battistelli, Elia Stefano; Benetti, Micol; Cabass, Giovanni; de Bernardis, Paolo; di Serego Alighieri, Sperello; di Valentino, Eleonora; Gerbino, Martina; Giusarma, Elena; Gruppuso, Alessandro; Liguori, Michele; Masi, Silvia; Norgaard-Nielsen, Hans Ulrik; Rosati, Piero; Salvati, Laura; Trombetti, Tiziana; Vielva, Patricio

2016-04-01

Recent cosmic microwave background (CMB) data in temperature and polarization have reached high precision in estimating all the parameters that describe the current so-called standard cosmological model. Recent results about the integrated Sachs-Wolfe (ISW) effect from CMB anisotropies, galaxy surveys, and their cross-correlations are presented. Looking at fine signatures in the CMB, such as the lack of power at low multipoles, the primordial power spectrum (PPS) and the bounds on non-Gaussianities, complemented by galaxy surveys, we discuss inflationary physics and the generation of primordial perturbations in the early universe. Three important topics in particle physics, the bounds on neutrinos masses and parameters, on thermal axion mass and on the neutron lifetime derived from cosmological data are reviewed, with attention to the comparison with laboratory experiment results. Recent results from cosmic polarization rotation (CPR) analyses aimed at testing the Einstein equivalence principle (EEP) are presented. Finally, we discuss the perspectives of next radio facilities for the improvement of the analysis of future CMB spectral distortion experiments.

Future HEP Accelerators: The US Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhat, Pushpalatha; Shiltsev, Vladimir

2015-11-02

Accelerator technology has advanced tremendously since the introduction of accelerators in the 1930s, and particle accelerators have become indispensable instruments in high energy physics (HEP) research to probe Nature at smaller and smaller distances. At present, accelerator facilities can be classified into Energy Frontier colliders that enable direct discoveries and studies of high mass scale particles and Intensity Frontier accelerators for exploration of extremely rare processes, usually at relatively low energies. The near term strategies of the global energy frontier particle physics community are centered on fully exploiting the physics potential of the Large Hadron Collider (LHC) at CERN throughmore » its high-luminosity upgrade (HL-LHC), while the intensity frontier HEP research is focused on studies of neutrinos at the MW-scale beam power accelerator facilities, such as Fermilab Main Injector with the planned PIP-II SRF linac project. A number of next generation accelerator facilities have been proposed and are currently under consideration for the medium- and long-term future programs of accelerator-based HEP research. In this paper, we briefly review the post-LHC energy frontier options, both for lepton and hadron colliders in various regions of the world, as well as possible future intensity frontier accelerator facilities.« less

Optofluidics incorporating actively controlled micro- and nano-particles

PubMed Central

Kayani, Aminuddin A.; Khoshmanesh, Khashayar; Ward, Stephanie A.; Mitchell, Arnan; Kalantar-zadeh, Kourosh

2012-01-01

The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

Statistical physics of vehicular traffic and some related systems

NASA Astrophysics Data System (ADS)

Chowdhury, Debashish; Santen, Ludger; Schadschneider, Andreas

2000-05-01

In the so-called “microscopic” models of vehicular traffic, attention is paid explicitly to each individual vehicle each of which is represented by a “particle”; the nature of the “interactions” among these particles is determined by the way the vehicles influence each others’ movement. Therefore, vehicular traffic, modeled as a system of interacting “particles” driven far from equilibrium, offers the possibility to study various fundamental aspects of truly nonequilibrium systems which are of current interest in statistical physics. Analytical as well as numerical techniques of statistical physics are being used to study these models to understand rich variety of physical phenomena exhibited by vehicular traffic. Some of these phenomena, observed in vehicular traffic under different circumstances, include transitions from one dynamical phase to another, criticality and self-organized criticality, metastability and hysteresis, phase-segregation, etc. In this critical review, written from the perspective of statistical physics, we explain the guiding principles behind all the main theoretical approaches. But we present detailed discussions on the results obtained mainly from the so-called “particle-hopping” models, particularly emphasizing those which have been formulated in recent years using the language of cellular automata.

Pions to Quarks

NASA Astrophysics Data System (ADS)

Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian

2009-01-01

Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the neutrino Frederick Reines; 25. Recollections on the establishment of the weak-interaction notion Bruno M. Pontecorvo; 26. Symmetry and conservation laws in particle physics in the fifties Louis Michel; 27. A connection between the strong and weak interactions Sam B. Treiman; Part VII. Weak interactions and parity nonconservation; 29. The nondiscovery of parity nonconservation Allan Franklin; 30. K-meson decays and parity violation Richard H. Dalitz; 31. An Experimentalist's Perspective Val L. Fitch; 32. The early experiments leading to the V - A interaction Valentine L. Telegdi; 33. Midcentury adventures in particles physics E. C. G. Sudarshan; Part VIII. The particle physics community; 34. The postwar political economy of high-energy physics Robert Seidel; 35. The history of CERN during the early 1950s Edoardo Amaldi; 36. Arguments pro and contra the European laboratory in the participating countries Armin Hermann; 37. Physics and excellences of the life it brings Abdus Salam; 38. Social aspects of Japanese particle physics in the 1950s Michiji Konuma; Part IX. Theories of hadrons; 39. The early S-matrix theory and its propagation (1942-1952) Helmut Rechenberg; 40. From field theory to phenomenology: the history of dispersion relations Andy Pickering; 41. Particles as S-matrix poles: hadron democracy Geoffrey F. Chew; 42. The general theory of quantised fields in the 1950s Arthur S. Wrightman; 43. The classification and structure of hadrons Yuval Ne'eman; 44. Gauge principle, vector-meson dominance and spontaneous symmetry breaking Yoichiro Nambu; Part X. Personal overviews; 45. Scientific impact of the first decade of the Rochester conferences (1950-1960) Robert E. Marshak; 46. Some reflections on the history of particle physics in the 1950s Silvan S. Schweber; 47. Progress in elementary particle theory 1950-1964 Murray Gell-Mann.

Final Progress Report: Internship at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunham, Ryan Q.

2012-08-10

Originally I was tasked fluidized bed modeling, however, I changed projects. While still working with ANSYS Fluent, I performed a study of particle tracks in glove boxes. This is useful from a Health-Physics perspective, dealing respirable particles that can be hazardous to the human body. I iteratively tested different amounts of turbulent particles in a steady-state flow. The goal of this testing was to discover how Fluent handles built-in Rosin-Rammler distributions for particle injections. I worked on the health physics flow problems and distribution analysis under the direction of two mentors, Bruce Letellier and Dave Decroix. I set up andmore » ran particle injection calculations using Fluent. I tried different combinations of input parameters to produce sets of 500,000, 1 million, and 1.5 million particles to determine what a good test case would be for future experiments. I performed a variety of tasks in my work as an Undergraduate Student Intern at LANL this summer, and learned how to use a powerful CFD application in addition to expanding my skills in MATLAB. I enjoyed my work at LANL and hope to be able to use the experience here to further my career in the future working in a security-conscious environment. My mentors provided guidance and help with all of my projects and I am grateful for the opportunity to work at Los Alamos National Laboratory.« less

The Chameleon Effect: characterization challenges due to the variability of nanoparticles and their surfaces of nanoparticles and their surfaces

NASA Astrophysics Data System (ADS)

Baer, Donald R.

2018-05-01

Nanoparticles in a variety of forms are increasing important in fundamental research, technological and medical applications, and environmental or toxicology studies. Physical and chemical drivers that lead to multiple types of particle instabilities complicate both the ability to produce, appropriately characterize, and consistently deliver well-defined particles, frequently leading to inconsistencies and conflicts in the published literature. This perspective suggests that provenance information, beyond that often recorded or reported, and application of a set of core characterization methods, including a surface sensitive technique, consistently applied at critical times can serve as tools in the effort minimize reproducibility issues.

Dressed photons from the viewpoint of photon localization: the entrance to the off-shell science

NASA Astrophysics Data System (ADS)

Saigo, Hayato; Ojima, Izumi; Ohtsu, Motoichi

2017-12-01

In the present paper, a new aspect of the interplay is examined between mathematical-physical arguments and light-matter fusion technologies in terms of the concept of "effective mass", starting from a question: Who has seen a free photon? Owing to the general results due to Newton-Wigner and to Wightman, a position operator is absent for massless free particles with non-zero finite spins, and hence, we cannot observe free photons in any local space regions. To solve this paradox of "photon localization", the effective mass of a photon needs to be generated through the couplings of photons with matter. Here "polaritons" picture as a basic notion in optical and solid physics is shown to verify this viewpoint, which is seen to apply also to more general settings . Focusing on the role played by nanoparticles, we reach a new look at the notion of "dressed photons" as off-shell particles. The perspective above shows that essential mathematical structure of quantum field theory for the so-called elementary particles in subatomic scale can also be applied to certain phenomena in the nano-scale.

Direct and Indirect Dark Matter Detection in Gauge Theories (in Portuguese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Queiroz, Farinaldo

The Dark matter (DM) problem constitutes a key question at the interface among Particle Physics, Astrophysics and Cosmology. The observational data which have been accumulated in the last years point to an existence of non baryonic amount of DM. Since the Standard Model (SM) does not provide any candidate for such non-baryonic DM, the evidence of DM is a major indication for new physics beyond the SM. We will study in this work one of the most popular DM candidates, the so called WIMPs (Weakly Interacting Massive Particles) from a direct and indirect detection perspective. In order to approach themore » direct and indirect dection of DM in the context of Particle Physics in a more pedagogic way, we will begin our discussion talking about a minimal extension of the SM. Later we will work on the subject in a 3-3-1 model. Next, we will study the role of WIMPs in the Big Bang Nucleosynthesis. Lastly, we will look for indirect DM signals in the center of our galaxy using the NASA Satellite, called Fermi-LAT. Through a comprehensive analysis of the data events observed by Fermi-LAT and some background models, we will constrain the dark matter annihilation cross section for several annihilation channels and dark matter halo profiles.« less

Structure of Cometary Dust Particles

NASA Astrophysics Data System (ADS)

Levasseur-Regourd, A. C.; Hadamcik, E.; Lasue, J.

2004-11-01

The recent encounter of Stardust with comet 81P/Wild 2 has provided highly spatially resolved data about dust particles in the coma. They show intense swarms and bursts of particles, suggest the existence of fragmenting low-density particles formed of higher density sub-micrometer components [1], and definitely confirm previous results (inferred from Giotto encounter with comet Grigg-Skjellerup [2] and remote light scattering observations [3]). The light scattering properties (mostly polarization, which does not depend upon disputable normalizations) of dust in cometary comae will be summarized, with emphasis on the spatial changes and on the wavelength and phase angle dependence. Experimental and numerical simulations are needed to translate these observed light scattering properties in terms of physical properties of the dust particles (e.g. size, morphology, albedo, porosity). New experimental simulations (with fluffy mixtures of sub-micron sized silica and carbon grains) and new numerical simulations (with fractal aggregates of homogeneous or core-mantled silicate and organic grains) will be presented. The results are in favor of highly porous particles built up (by ballistic-cluster-cluster agglomeration) from grains of interstellar origin. The perspectives offered by laboratory simulations with aggregates built under conditions representative of the early solar system on board the International Space Station will be presented, together with the perspectives offered by future experiments on board the Rosetta cometary probe. Supports from CNES and ESA are acknowledged [1] Tuzzolino et al., Science, 304, 1776, 2004, [2] N. McBride et al., Mon. Not. R. Astron. Soc., 289, p. 535-553, 1997, [3] Levasseur-Regourd and Hadamcik, J. Quant. Spectros. Radiat. Transfer, 79-80, 903-910, 2003.

The phenomenology of maverick dark matter

NASA Astrophysics Data System (ADS)

Krusberg, Zosia Anna Celina

Astrophysical observations from galactic to cosmological scales point to a substantial non-baryonic component to the universe's total matter density. Although very little is presently known about the physical properties of dark matter, its existence offers some of the most compelling evidence for physics beyond the standard model (BSM). In the weakly interacting massive particle (WIMP) scenario, the dark matter consists of particles that possess weak-scale interactions with the particles of the standard model, offering a compelling theoretical framework that allows us to understand the relic abundance of dark matter as a natural consequence of the thermal history of the early universe. From the perspective of particle physics phenomenology, the WIMP scenario is appealing for two additional reasons. First, many theories of BSM physics contain attractive WIMP candidates. Second, the weak-scale interactions between WIMPs and standard model particles imply the possibility of detecting scatterings between relic WIMPs and detector nuclei in direct detection experiments, products of WIMP annihilations at locations throughout the galaxy in indirect detection programs, and WIMP production signals at high-energy particle colliders. In this work, we use an effective field theory approach to study model-independent dark matter phenomenology in direct detection and collider experiments. The maverick dark matter scenario is defined by an effective field theory in which the WIMP is the only new particle within the energy range accessible to the Large Hadron Collider (LHC). Although certain assumptions are necessary to keep the problem tractable, we describe our WIMP candidate generically by specifying only its spin and dominant interaction form with standard model particles. Constraints are placed on the masses and coupling constants of the maverick WIMPs using the Wilkinson Microwave Anisotropy Probe (WMAP) relic density measurement and direct detection exclusion data from both spin-independent (XENON100 and SuperCDMS) and spin-dependent (COUPP) experiments. We further study the distinguishability of maverick WIMP production signals at the Tevatron and the LHC---at its early and nominal configurations---using standard simulation packages, place constraints on maverick WIMP properties using existing collider data, and determine projected mass reaches in future data from both colliders. We find ourselves in a unique era of theoretically-motivated, high-precision dark matter searches that hold the potential to give us important insights, not only into the nature of dark matter, but also into the physics that lies beyond the standard model.

The Chameleon Effect: Characterization Challenges Due to the Variability of Nanoparticles and Their Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Donald R.

Nanoparticles in a variety of forms are of increasing importance in fundamental research, technological and medical applications, and environmental or toxicology studies. Physical and chemical drivers that lead to multiple types of particle instabilities complicate both the ability to produce and consistently deliver well defined particles and their appropriate characterization, frequently leading to inconsistencies and conflicts in the published literature. This perspective suggests that provenance information, beyond that often recorded or reported, and application of a set of core characterization methods, including a surface sensitive technique, consistently applied at critical times can serve as tools in the effort minimize reproducibilitymore » issues.« less

ICHEP 2014 Summary: Theory Status after the First LHC Run

NASA Astrophysics Data System (ADS)

Pich, Antonio

2016-04-01

A brief overview of the main highlights discussed at ICHEP 2014 is presented. The experimental data confirm that the scalar boson discovered at the LHC couples to other particles as predicted in the Standard Model. This constitutes a great success of the present theoretical paradigm, which has been confirmed as the correct description at the electroweak scale. At the same time, the negative searches for signals of new phenomena tightly constrain many new-physics scenarios, challenging previous theoretical wisdom and opening new perspectives in fundamental physics. Fresh ideas are needed to face the many pending questions unanswered within the Standard Model framework.

Collisionless Shocks and Particle Acceleration.

NASA Astrophysics Data System (ADS)

Malkov, M.

2016-12-01

Collisionless shocks emerged in the 50s and 60s of the last century as an important branch of plasma physics and have remained ever since. New applications pose new challenges to our understanding of collisionless shock mechanisms. Particle acceleration in astrophysical settings, primarily studied concerning the putative origin of cosmic rays (CR) in supernova remnant (SNR) shocks, stands out with the collisionless shock mechanism being the key. Among recent laboratory applications, a laser-based tabletop proton accelerator is an affordable compact alternative to big synchrotron accelerators. The much-anticipated proof of cosmic ray (CR) acceleration in supernova remnants is hindered by our limited understanding of collisionless shock mechanisms. Over the last decade, dramatically improved observations were puzzling the theorists with unexpected discoveries. The difference between the helium/carbon and proton CR rigidity (momentum to charge ratio) spectra, seemingly inconsistent with the acceleration and propagation theories, and the perplexing positron excess in the 10-300 GeV range are just two recent examples. The latter is now also actively discussed in the particle physics and CR communities as a possible signature of decay or annihilation of hypothetical dark matter particles. By considering an initial (injection) phase of a diffusive shock acceleration mechanism, including particle reflection off the shock front - where an elemental similarity of particle dynamics does not apply - I will discuss recent suggestions of how to address the new data from the collisionless shock perspective. The backreaction of accelerated particles on the shock structure, its environment, and visibility across the electromagnetic spectrum from radio to gamma rays is another key aspect of collisionless shock that will be discussed.

The Gran Sasso Underground Laboratory

NASA Astrophysics Data System (ADS)

Coccia, Eugenio

2012-12-01

Thirty years have passed since, thanks to Antonino Zichichi, the project for the largest underground laboratory in the world was conceived and brought to the attention of Italian authorities. The Gran Sasso National Laboratories of INFN have become a scientific reality of worldwide pre-eminence, in an expanding area of research where elementary particle physics, astrophysics and cosmology overlap. I briefly present here the main scientific challenges of underground laboratories and the activity and future perspectives of the INFN Gran Sasso Laboratory.

Current Status and Future Perspectives of the LUCIFER Experiment

DOE PAGES

Beeman, J. W.; Bellini, F.; Benetti, P.; ...

2013-09-30

In the field of fundamental particle physics, the neutrino has become more and more important in the last few years, since the discovery of its mass. In particular, the ultimate nature of the neutrino (if it is a Dirac or a Majorana particle) plays a crucial role not only in neutrino physics, but also in the overall framework of fundamental particle interactions and in cosmology. The only way to disentangle its ultimate nature is to search for the neutrinoless double beta decay. The idea of LUCIFER is to combine the bolometric technique proposed for the CUORE experiment with the bolometricmore » light detection technique used in cryogenic dark matter experiments. The bolometric technique allows an extremely good energy resolution while its combination with the scintillation detection offers an ultimate tool for background rejection. The goal of LUCIFER is not only to build a background-free small-scale experiment but also to directly prove the potentiality of this technique. Preliminary tests on several detectors containing different interesting DBD emitters have clearly demonstrated the excellent background rejection capabilities that arise from the simultaneous, independent, double readout of heat and scintillation light.« less

Future hadron colliders: From physics perspectives to technology R&D

NASA Astrophysics Data System (ADS)

Barletta, William; Battaglia, Marco; Klute, Markus; Mangano, Michelangelo; Prestemon, Soren; Rossi, Lucio; Skands, Peter

2014-11-01

High energy hadron colliders have been instrumental to discoveries in particle physics at the energy frontier and their role as discovery machines will remain unchallenged for the foreseeable future. The full exploitation of the LHC is now the highest priority of the energy frontier collider program. This includes the high luminosity LHC project which is made possible by a successful technology-readiness program for Nb3Sn superconductor and magnet engineering based on long-term high-field magnet R&D programs. These programs open the path towards collisions with luminosity of 5×1034 cm-2 s-1 and represents the foundation to consider future proton colliders of higher energies. This paper discusses physics requirements, experimental conditions, technological aspects and design challenges for the development towards proton colliders of increasing energy and luminosity.

Deposition kinetics of colloidal particles at high ionic strengths

NASA Astrophysics Data System (ADS)

Cejas, Cesare; Monti, Fabrice; Truchet, Marine; Burnouf, Jean-Pierre; Tabeling, Patrick

Using microfluidic experiments, we describe the deposition of a fluid suspension of weakly brownian particles transported in a straight channel at small Reynolds numbers under conditions of high ionic strengths. Our studies fall in a regime where electrostatic interactions are neglected and particle-wall van der Waals interactions govern the deposition mechanism on channel walls. We calculate the deposition kinetics analytically for a wide range of physical parameters. We find that the theory agrees with numerical Langevin simulations, which both confirm the experimental results. From this analysis, we demonstrate a universal dimensionless deposition function described by contributions from advection-diffusion transport and adhesion interactions (Hamaker constant). Results show that we accurately confirm the theoretical expression for the deposition kinetics. From a surface science perspective, working in the van der Waals regime enables to measure the Hamaker constant, a task that would take much longer to perform with the standard AFM. Funding from Sanofi Recherche and ESPCI.

From the sea to the laboratory: Characterization of microplastic as prerequisite for the assessment of ecotoxicological impact.

PubMed

Potthoff, Annegret; Oelschlägel, Kathrin; Schmitt-Jansen, Mechthild; Rummel, Christoph Daniel; Kühnel, Dana

2017-05-01

The presence of microplastic (MP) in the aquatic environment is recognized as a global-scale pollution issue. Secondary MP particles result from an ongoing fragmentation process governed by various biotic and abiotic factors. For a reliable risk assessment of these MP particles, knowledge about interactions with biota is needed. However, extensive testing with standard organisms under reproducible laboratory conditions with well-characterized MP suspensions is not available yet. As MP in the environment represents a mixture of particles differing in properties (e.g., size, color, polymer type, surface characteristics), it is likely that only specific particle fractions pose a threat towards organisms. In order to assign hazardous effects to specific particle properties, these characteristics need to be analyzed. As shown by the testing of particles (e.g. nanoparticles), characteristics other than chemical properties are important for the emergence of toxicity in organisms, and parameters such as surface area or size distribution need consideration. Therefore, the use of "well-defined" particles for ecotoxicological testing (i.e., standard particles) facilitates the establishment of causal links between physical-chemical properties of MP particles and toxic effects in organisms. However, the benefits of well-defined particles under laboratory conditions are offset by the disadvantage of the unknown comparability with MP in the environment. Therefore, weathering effects caused by biological, chemical, physical or mechanical processes have to be considered. To date, the characterization of the progression of MP weathering based on powder and suspension characterization methods is in its infancy. The aim of this commentary is to illustrate the prerequisites for testing MP in the laboratory from 3 perspectives: (i) knowledge of particle properties; (ii) behavior of MP in test setups involving ecotoxicological test organisms; and (iii) accordingly, test conditions that may need adjustment. Only under those prerequisites will reliable hazard assessment of MP be feasible. Integr Environ Assess Manag 2017;13:500-504. © 2017 SETAC. © 2017 SETAC.

Highlights and Perspectives from the CMS Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, Joel Nathan

2017-09-09

In 2016, the Large Hadron Collider provided proton-proton collisions at 13 TeV center-of-mass energy and achieved very high luminosity and reliability. The performance of the CMS Experiment in this running period and a selection of recent physics results are presented. These include precision measurements and searches for new particles. The status and prospects for data-taking in 2017 and a brief summary of the highlights of the High Luminosity (HL-LHC) upgrade of the CMS detector are also presented.

Gauge/Gravity Duality

ScienceCinema

Polchinski, Joseph

2017-12-22

Gauge theories, which describe the particle interactions, are well understood, while quantum gravity leads to many puzzles. Remarkably, in recent years we have learned that these are actually dual, the same system written in different variables. On the one hand, this provides our most precise description of quantum gravity, resolves some long-standing paradoxes, and points to new principles. On the other, it gives a new perspective on strong interactions, with surprising connections to other areas of physics. I describe these ideas, and discuss current and future directions.

Physical approach to quantum networks with massive particles

NASA Astrophysics Data System (ADS)

Andersen, Molte Emil Strange; Zinner, Nikolaj Thomas

2018-04-01

Assembling large-scale quantum networks is a key goal of modern physics research with applications in quantum information and computation. Quantum wires and waveguides in which massive particles propagate in tailored confinement is one promising platform for realizing a quantum network. In the literature, such networks are often treated as quantum graphs, that is, the wave functions are taken to live on graphs of one-dimensional edges meeting in vertices. Hitherto, it has been unclear what boundary conditions on the vertices produce the physical states one finds in nature. This paper treats a quantum network from a physical approach, explicitly finds the physical eigenstates and compares them to the quantum-graph description. The basic building block of a quantum network is an X-shaped potential well made by crossing two quantum wires, and we consider a massive particle in such an X well. The system is analyzed using a variational method based on an expansion into modes with fast convergence and it provides a very clear intuition for the physics of the problem. The particle is found to have a ground state that is exponentially localized to the center of the X well, and the other symmetric solutions are formed so to be orthogonal to the ground state. This is in contrast to the predictions of the conventionally used so-called Kirchoff boundary conditions in quantum graph theory that predict a different sequence of symmetric solutions that cannot be physically realized. Numerical methods have previously been the only source of information on the ground-state wave function and our results provide a different perspective with strong analytical insights. The ground-state wave function has a spatial profile that looks very similar to the shape of a solitonic solution to a nonlinear Schrödinger equation, enabling an analytical prediction of the wave number. When combining multiple X wells into a network or grid, each site supports a solitonlike localized state. These localized solutions only couple to each other and are able to jump from one site to another as if they were trapped in a discrete lattice.

Nuclear Physics with 10 PW laser beams at Extreme Light Infrastructure - Nuclear Physics (ELI-NP)

NASA Astrophysics Data System (ADS)

Zamfir, N. V.

2014-05-01

The field of the uncharted territory of high-intensity laser interaction with matter is confronted with new exotic phenomena and, consequently, opens new research perspectives. The intense laser beams interacting with a gas or solid target generate beams of electrons, protons and ions. These beams can induce nuclear reactions. Electrons also generate ions high-energy photons via bremsstrahlung processes which can also induce nuclear reactions. In this context a new research domain began to form in the last decade or so, namely nuclear physics with high power lasers. The observation of high brilliance proton beams of tens of MeV energy from solid targets has stimulated an intense research activity. The laser-driven particle beams have to compete with conventional nuclear accelerator-generated beams. The ultimate goal is aiming at applications of the laser produced beams in research, technology and medicine. The mechanism responsible for ion acceleration are currently subject of intensive research in many laboratories in the world. The existing results, experimental and theoretical, and their perspectives are reviewed in this article in the context of IZEST and the scientific program of ELI-NP.

Benefits of applying low-temperature plasma treatment to wound care and hemostasis from the viewpoints of physics and pathology

NASA Astrophysics Data System (ADS)

Shimizu, Tetsuji; Ikehara, Yuzuru

2017-12-01

Over the last decade, low-temperature plasma (LTP) technology has reached the life sciences and introduced the benefits of using such technology at atmospheric pressure for medical applications. The active elements from LTP, such as reactive molecular species, charged particles and photons, appear to react with biomolecules on wounds and at bleeding points. This action by LTP might be analogous with semiconductor fabrication techniques such as etching and surface modification. From this perspective, we discuss the general aspects and principles of LTP devices used at atmospheric pressure in wound care and hemostasis as an interdisciplinary fusion of applied physics and pathology.

Quark soup al dente: applied superstring theory

NASA Astrophysics Data System (ADS)

Myers, R. C.; Vázquez, S. E.

2008-06-01

In recent years, experiments have discovered an exotic new state of matter known as the strongly coupled quark gluon plasma (sQGP). At present, it seems that standard theoretical tools, such as perturbation theory and lattice gauge theory, are poorly suited to understand this new phase. However, recent progress in superstring theory has provided us with a theoretical laboratory for studying very similar systems of strongly interacting hot non-Abelian plasmas. This surprising new perspective extracts the fluid properties of the sQGP from physical processes in a black hole spacetime. Hence we may find the answers to difficult particle physics questions about the sQGP from straightforward calculations in classical general relativity.

Cerenkov luminescence imaging: physics principles and potential applications in biomedical sciences.

PubMed

Ciarrocchi, Esther; Belcari, Nicola

2017-12-01

Cerenkov luminescence imaging (CLI) is a novel imaging modality to study charged particles with optical methods by detecting the Cerenkov luminescence produced in tissue. This paper first describes the physical processes that govern the production and transport in tissue of Cerenkov luminescence. The detectors used for CLI and their most relevant specifications to optimize the acquisition of the Cerenkov signal are then presented, and CLI is compared with the other optical imaging modalities sharing the same data acquisition and processing methods. Finally, the scientific work related to CLI and the applications for which CLI has been proposed are reviewed. The paper ends with some considerations about further perspectives for this novel imaging modality.

A perspective on the contributions of Ronald C. Davidson to plasma physics

NASA Astrophysics Data System (ADS)

Wurtele, Jonathan S.

2016-10-01

Starting in the 1960s and continuing for half a century, Ronald C. Davidson made fundamental theoretical contributions to a wide range of areas of pure and applied plasma physics. Davidson was one of the founders of nonneutral plasma physics and a pioneer in developing and applying kinetic theory and nonlinear stability theorems to collective interaction processes and nonlinear dynamics of nonneutral plasmas and intense charged particle beams. His textbooks on nonneutral plasmas are the classic references for the field and educated generations of graduate students. Davidson was a strong advocate for applying the ideas of plasma theory to develop techniques that benefit other branches of science. For example, one of the major derivative fields enabled by nonneutral plasmas is the study of antimatter plasmas and the synthesis of antihydrogen. This talk will review a few highlights of Ronald Davidson's impact on plasma physics and related fields of science.

Clinical perspectives on pulmonary systemic and macromolecular delivery.

PubMed

Scheuch, Gerhard; Kohlhaeufl, Martin J; Brand, Peter; Siekmeier, Ruediger

2006-10-31

The large epithelial surface area, the high organ vascularization, the thin nature of the alveolar epithelium and the immense capacity for solute exchange are factors that led the lung to serve as an ideal administration route for the application of drugs for treatment of systemic disorders. However, the deposition behaviour of aerosol particles in the respiratory tract depends on a number of physical (e.g. properties of the particle), chemical (e.g. properties of the drug) and physiological (e.g. breathing pattern, pulmonary diseases) factors. If these are not considered, it will not be possible to deposit a reproducible and sufficient amount of drug in a predefined lung region by means of aerosol inhalation. The lack of consideration of such issues led to many problems in inhalation drug therapy for many years mainly because physiological background of aerosol inhalation was not fully understood. However, over the last 20 years, there has been considerable progress in aerosol research and in the understanding of the underlying mechanisms of particle inhalation and pulmonary particle deposition. As a consequence, an increasing number of studies have been performed for the lung administration of drugs using a variety of different inhalation techniques. This review describes the physical and in part some of the physiological requirements that need to be considered for the optimization of pulmonary drug delivery to target certain lung regions.

Lattice QCD and physics beyond the Standar Model: an experimentalist perspective

NASA Astrophysics Data System (ADS)

Artuso, Marina

2017-01-01

The new frontier in elementary particle physics is to find evidence for new physics that may lead to a deeper understanding of observations such as the baryon-antibaryon asymmetry of the universe, mass hierarchy, dark matter, or dark energy to name a few. Flavor physics provides a wealth of opportunities to find such signatures, and a vast body of data taken at e+e- b-factories and at hadron machines has provided valuable information, and a few tantalizing ``tensions'' with respect to the Standard Model predictions. While the window for new physics is still open, the chance that its manifestations will be subtle is very real. A vibrant experimental program is ongoing, and significant upgrades, such as the upgraded LHCb experiment at LHC and Belle 2 at KEKb, are imminent. One of the challenges in extracting new physics from flavor physics data is the need to relate observed hadron decays to fundamental particles and interactions. The continuous improvement of Lattice QCD predictions is a key element to achieve success in this quest. Improvements in algorithms and hardware have led to predictions of increasing precision on several fundamental matrix elements, and the continuous breaking of new grounds, thus allowing a broader spectrum of measurements to become relevant to this quest. An important aspect of the experiment-lattice synergy is a comparison between lattice predictions with experiment for a variety of hadronic quantities. This talk summarizes current synergies between lattice QCD theory and flavor physics experiments, and gives some highlights of expectations from future upgrades. this work was supported by NSF.

Werner Brandt legacy to PIXE: Past and present perspectives

NASA Astrophysics Data System (ADS)

Lapicki, Gregory

2014-01-01

Inner-shell ionization cross sections used in Particle-Induced X-ray Elemental (PIXE) analyses are routinely calculated in the ECPSSR [W. Brandt, G. Lapicki, Phys. Rev. A 23 (1981) 1717-1729] theory and/or semiempirical formulas scaled to that theory. Thirty years after the passing of Werner Brandt, with recognition of his seminal contributions to other research on positron physics and stopping power problems, the work and articles that progressed into the ECPSSR theory for inner-shell ionization by protons and heavier ions are recalled as Brandt's past legacy to the PIXE community. Applications of the ECPSSR and its evolution into the ECUSAR [G. Lapicki, Nucl. Instr. Meth. B 189 (2002) 8-20] theory over the last three decades are reviewed with perspectives on Brandt's present legacy.

Perspectives on handedness, life and physics.

PubMed

Axelsson, Sven

2003-08-01

In contrast to motion, matter will be conserved in all eternity. Structure and function will arise by the angular momentum of spinning spherical particles and their composites. Symmetry prevails in physics by equal amounts of left- and right-hand spinning entities, while life is asymmetric in this respect. Very rare deviations from the ubiquitous one-sided handedness in biology will probably explain the inert degradation resistant proteins in 'mad cow' type diseases. Velocities of physical events seems to be a most important feature and will explain for instance brain function and the true nature of neurodegenerative diseases. This biophysics of mind will in turn provide answers to many disputable aspects of physics such as the true nature of waves and gravity. Many current concepts in quantum physics will be invalidated, among them the uncertainty principle, the relativity to a fixed speed of light, the energy equation and the expansion of the Universe. Instead, decay and formation will balance each other in a continuum of matter in an intuitively cyclic Multiverse.

Principle of the electrically induced Transient Current Technique

NASA Astrophysics Data System (ADS)

Bronuzzi, J.; Moll, M.; Bouvet, D.; Mapelli, A.; Sallese, J. M.

2018-05-01

In the field of detector development for High Energy Physics, the so-called Transient Current Technique (TCT) is used to characterize the electric field profile and the charge trapping inside silicon radiation detectors where particles or photons create electron-hole pairs in the bulk of a semiconductor device, as PiN diodes. In the standard approach, the TCT signal originates from the free carriers generated close to the surface of a silicon detector, by short pulses of light or by alpha particles. This work proposes a new principle of charge injection by means of lateral PN junctions implemented in one of the detector electrodes, called the electrical TCT (el-TCT). This technique is fully compatible with CMOS technology and therefore opens new perspectives for assessment of radiation detectors performances.

ICPP: Relativistic Plasma Physics with Ultra-Short High-Intensity Laser Pulses

NASA Astrophysics Data System (ADS)

Meyer-Ter-Vehn, Juergen

2000-10-01

Recent progress in generating ultra-short high-intensity laser pulses has opened a new branch of relativistic plasma physics, which is discussed in this talk in terms of particle-in-cell (PIC) simulations. These pulses create small plasma volumes of high-density plasma with plasma fields above 10^12 V/m and 10^8 Gauss. At intensities beyond 10^18 W/cm^2, now available from table-top systems, they drive relativistic electron currents in self-focussing plasma channels. These currents are close to the Alfven limit and allow to study relativistic current filamentation. A most remarkable feature is the generation of well collimated relativistic electron beams emerging from the channels with energies up to GeV. In dense matter they trigger cascades of gamma-rays, e^+e^- pairs, and a host of nuclear and particle processes. One of the applications may be fast ignition of compressed inertial fusion targets. Above 10^23 W/cm^2, expected to be achieved in the future, solid-density matter becomes relativistically transparent for optical light, and the acceleration of protons to multi-GeV energies is predicted in plasma layers less than 1 mm thick. These results open completely new perspectives for plasma-based accelerator schemes. Three-dimensional PIC simulations turn out to be the superior tool to explore the relativistic plasma kinetics at such intensities. Results obtained with the VLPL code [1] are presented. Different mechanisms of particle acceleration are discussed. Both laser wakefield and direct laser acceleration in plasma channels (by a mechanism similar to inverse free electron lasers) have been identified. The latter describes recent MPQ experimental results. [1] A. Pukhov, J. Plasma Physics 61, 425 - 433 (1999): Three-dimensional electromagnetic relativistic particle-in-cell code VLPL (Virtual Laser Plasma Laboratory).

Time perspective and physical activity among central Appalachian adolescents.

PubMed

Gulley, Tauna

2013-04-01

Time perspective is a cultural behavioral concept that reflects individuals' orientations or attitudes toward the past, present, or future. Individuals' time perspectives influence their choices regarding daily activities. Time perspective is an important consideration when teaching adolescents about the importance of being physically active. However, little is known about the relationship between time perspective and physical activity among adolescents. The purpose of this study was to determine the time perspective of central Appalachian adolescents and explore the relationship between time perspective and physical activity. This study was guided by The theory of planned behavior (TPB). One hundred and ninety-three students completed surveys to examine time perspective and physical activity behaviors. Data were collected in one school. Results of this study can inform school nurses and high school guidance counselors about the importance of promoting a future-oriented time perspective to improve physical activity and educational outcomes.

Liquid Argon Calorimetry for ATLAS

NASA Astrophysics Data System (ADS)

Robinson, Alan

2008-05-01

This summer, the largest collaborative physics project since the Manhattan project will go online. One of four experiments for the Large Hadron Collider at CERN in Geneva, ATLAS, employs over 2000 people. Canadians have helped design, construct, and calibrate the liquid argon calorimeters for ATLAS to capture the products of the high energy collisions produced by the LHC. From an undergraduate's perspective, explore how these calorimeters are made to handle their harsh requirement. From nearly a billion proton-proton collisions a second, physicists hope to discover the Higgs boson and other new fundamental particles.

Analysis of gravity-induced particle motion and fluid perfusion flow in the NASA-designed rotating zero-head-space tissue culture vessel

NASA Technical Reports Server (NTRS)

Wolf, David A.; Schwarz, Ray P.

1991-01-01

The gravity induced motions, through the culture media, is calculated of living tissue segments cultured in the NASA rotating zero head space culture vessels. This is then compared with the media perfusion speed which is independent of gravity. The results may be interpreted as a change in the physical environment which will occur by operating the NASA tissue culture systems in actual microgravity (versus unit gravity). The equations governing particle motions which induce flows at the surface of tissues contain g terms. This allows calculation of the fluid flow speed, with respect to a cultured particle, as a function of the external gravitational field strength. The analysis is approached from a flow field perspective. Flow is proportional to the shear exerted on a structure which maintains position within the field. The equations are solved for the deviation of a particle from its original position in a circular streamline as a function of time. The radial deviation is important for defining the operating limits and dimensions of the vessel because of the finite radius at which particles necessarily intercept the wall. This analysis uses a rotating reference frame concept.

The Poynting-Robertson effect: A critical perspective

NASA Astrophysics Data System (ADS)

Klačka, J.; Petržala, J.; Pástor, P.; Kómar, L.

2014-04-01

Physics of the Poynting-Robertson (P-R) effect is discussed and compared with the statements published in the past 30 years. Relativistically covariant formulation reveals the essence of the P-R effect and points out to nonphysical explanations in scientific papers and monographs. Although the final equation of motion m dv→/dt=(SA‧Q‾pr‧/c)[(1-v→·e→/c)e→-v→/c] has been usually correctly presented and used, its derivation and explanation of its essence is frequently incorrect. The difference between the effects of solar electromagnetic and corpuscular (solar wind) radiation is stressed. The force acting on the particle due to the solar wind (the simple case of radial solar wind velocity is considered) is F→sw=Fsw[(1-v→·e→/vsw)e→-x‧v→/vsw], where Fsw is the force on the stationary particle, vsw is the heliocentric solar-wind speed, and, the value of x‧ depends on material properties of the particle (1 < x‧ < 3). We present secular orbital evolution of dust particle under the action of the P-R effect. Initial conditions are included. Time of spiralling of the particle into the Sun is analytically calculated. Secular evolutions of perihelion and aphelion distances are investigated.

Stereo multiplexed holographic particle image velocimeter

DOEpatents

Adrian, Ronald J.; Barnhart, Donald H.; Papen, George A.

1996-01-01

A holographic particle image velocimeter employs stereoscopic recording of particle images, taken from two different perspectives and at two distinct points in time for each perspective, on a single holographic film plate. The different perspectives are provided by two optical assemblies, each including a collecting lens, a prism and a focusing lens. Collimated laser energy is pulsed through a fluid stream, with elements carried in the stream scattering light, some of which is collected by each collecting lens. The respective focusing lenses are configured to form images of the scattered light near the holographic plate. The particle images stored on the plate are reconstructed using the same optical assemblies employed in recording, by transferring the film plate and optical assemblies as a single integral unit to a reconstruction site. At the reconstruction site, reconstruction beams, phase conjugates of the reference beams used in recording the image, are directed to the plate, then selectively through either one of the optical assemblies, to form an image reflecting the chosen perspective at the two points in time.

Stereo multiplexed holographic particle image velocimeter

DOEpatents

Adrian, R.J.; Barnhart, D.H.; Papen, G.A.

1996-08-20

A holographic particle image velocimeter employs stereoscopic recording of particle images, taken from two different perspectives and at two distinct points in time for each perspective, on a single holographic film plate. The different perspectives are provided by two optical assemblies, each including a collecting lens, a prism and a focusing lens. Collimated laser energy is pulsed through a fluid stream, with elements carried in the stream scattering light, some of which is collected by each collecting lens. The respective focusing lenses are configured to form images of the scattered light near the holographic plate. The particle images stored on the plate are reconstructed using the same optical assemblies employed in recording, by transferring the film plate and optical assemblies as a single integral unit to a reconstruction site. At the reconstruction site, reconstruction beams, phase conjugates of the reference beams used in recording the image, are directed to the plate, then selectively through either one of the optical assemblies, to form an image reflecting the chosen perspective at the two points in time. 13 figs.

The Butterfly and the Photon:. New Perspectives on Unpredictability, and the Notion of Casual Reality, in Quantum Physics

NASA Astrophysics Data System (ADS)

Palmer, T. N.

2012-12-01

This essay discusses a proposal that draws together the three great revolutionary theories of 20th Century physics: quantum theory, relativity theory and chaos theory. Motivated by the Bohmian notion of implicate order, and what in chaos theory would be described as a strange attractor, the proposal attributes special ontological significance to certain non-computable, dynamically invariant state-space geometries for the universe as a whole. Studying the phenomenon of quantum interference, it is proposed to understand quantum wave-particle duality, and indeed classical electromagnetism, in terms of particles in space time and waves on this state space geometry. Studying the EPR experiment, the acausal constraints that this invariant geometry provides on spatially distant degrees of freedom, provides a way for the underlying dynamics to be consistent with the Bell theorem, yet be relativistically covariant ("nonlocality without nonlocality"). It is suggested that the physical basis for such non-computable geometries lies in properties of gravity with the information irreversibility implied by black hole no-hair theorems being crucial. In conclusion it is proposed that quantum theory may be emergent from an extended theory of gravity which is geometric not only in space time, but also in state space. Such a notion would undermine most current attempts to "quantise gravity".

Chemical fractionation and speciation modelling for optimization of ion-exchange processes to recover palladium from industrial wastewater.

PubMed

Folens, K; Van Hulle, S; Vanhaecke, F; Du Laing, G

2016-01-01

Palladium is used in several industrial applications and, given its high intrinsic value, intense efforts are made to recover the element. In this hydrometallurgic perspective, ion-exchange (IEX) technologies are principal means. Yet, without incorporating the chemical and physical properties of the Pd present in real, plant-specific conditions, the recovery cannot reach its technical nor economic optimum. This study characterized a relevant Pd-containing waste stream of a mirror manufacturer to provide input for a speciation model, predicting the Pd speciation as a function of pH and chloride concentration. Besides the administered neutral PdCl2 form, both positively and negatively charged [PdCln](2-n) species occur depending on the chloride concentration in solution. Purolite C100 and Relite 2AS IEX resins were selected and applied in combination with other treatment steps to optimize the Pd recovery. A combination of the cation and anion exchange resins was found successful to quantitatively recover Pd. Given the fact that Pd was also primarily associated with particles, laboratory-scale experiments focused on physical removal of the Pd-containing flow were conducted, which showed that particle-bound Pd can already be removed by physical pre-treatment prior to IEX, while the ionic fraction remains fully susceptible to the IEX mechanism.

Phospholipid Bilayers: Stability and Encapsulation of Nanoparticles

NASA Astrophysics Data System (ADS)

Alipour, Elnaz; Halverson, Duncan; McWhirter, Samantha; Walker, Gilbert C.

2017-05-01

Nanoparticles are widely studied for their potential medical uses in diagnostics and therapeutics. The interface between a nanoparticle and its target has been a focus of research, both to guide the nanoparticle and to prevent it from deactivating. Given nature's frequent use of phospholipid vesicles as carriers, much attention has been paid to phospholipids as a vehicle for drug delivery. The physical chemistry of bilayer formation and nanoparticle encapsulation is complex, touching on fundamental properties of hydrophobicity. Understanding the design rules for particle synthesis and encapsulation is an active area of research. The aim of this review is to provide a perspective on what preparative guideposts have been empirically discovered and how these are related to theoretical understanding. In addition, we aim to summarize how modern theory is beginning to help guide the design of functional particles that can effectively cross biological membranes.

Global properties of physically interesting Lorentzian spacetimes

NASA Astrophysics Data System (ADS)

Nawarajan, Deloshan; Visser, Matt

Under normal circumstances most members of the general relativity community focus almost exclusively on the local properties of spacetime, such as the locally Euclidean structure of the manifold and the Lorentzian signature of the metric tensor. When combined with the classical Einstein field equations this gives an extremely successful empirical model of classical gravity and classical matter — at least as long as one does not ask too many awkward questions about global issues, (such as global topology and global causal structure). We feel however that this is a tactical error — even without invoking full-fledged “quantum gravity” we know that the standard model of particle physics is also an extremely good representation of some parts of empirical reality; and we had better be able to carry over all the good features of the standard model of particle physics — at least into the realm of semi-classical quantum gravity. Doing so gives us some interesting global features that spacetime should possess: On physical grounds spacetime should be space-orientable, time-orientable, and spacetime-orientable, and it should possess a globally defined tetrad (vierbein, or in general a globally defined vielbein/n-bein). So on physical grounds spacetime should be parallelizable. This strongly suggests that the metric is not the fundamental physical quantity; a very good case can be made for the tetrad being more fundamental than the metric. Furthermore, a globally-defined “almost complex structure” is almost unavoidable. Ideas along these lines have previously been mooted, but much is buried in the pre-arXiv literature and is either forgotten or inaccessible. We shall revisit these ideas taking a perspective very much based on empirical physical observation.

BOOK REVIEW: Microscopic Dynamics of Plasmas and Chaos

NASA Astrophysics Data System (ADS)

Elskens, Y.; Escande, D.

2003-04-01

Some of the key intellectual foundations of plasma physics are in danger of becoming a lost art. Fortunately, however, this threat recedes with the publication of this valuable book. It renders accessible those aspects of theoretical plasma physics that are best approached from the perspectives of classical mechanics, in both its early nineteenth century and late twentieth century manifestations. Half a century has elapsed since the publication of seminal papers such as those by Bohm and Pines (1951), van Kampen (1955), and Bernstein, Greene and Kruskal (1957). These papers served to address a fundamental question of physics - namely the relation between degrees of freedom that exist at the individual particle level of description, and those that exist at the collective level - in the plasma context. The authors of the present book have played a major role in the investigation of this question from an N-body standpoint, which can be divided into two linked themes. First, those topics that can be illuminated by analytical methods that lie in the tradition of classical mechanics that stretches back to Lagrange, Legendre and Hamilton. Second, those topics that benefit from the insights developed following the redevelopment of classical mechanics in relation to chaos theory in the 1980s and subsequently. The working plasma physicist who wishes to dig more deeply in this field is faced at present with a number of challenges. These may include a perception that this subfield is of limited relevance to mission-oriented questions of plasma performance; a perception of the research literature as being self-contained and inaccessible; and, linked to this, unfamiliarity with the mathematical tools. The latter problem is particularly pressing, given the limited coverage of classical mechanics in many undergraduate physics courses. The book by Elskens and Escande meets many of the challenges outlined above. The rewards begin early, by the end of the second chapter, with beautiful derivations of the self-consistent Lagrangian for wave-particle interactions, followed by an equivalent Hamiltonian formulation in terms of action-angle variables. In the following two chapters, these and related techniques are used to explore the deepest topics of plasma dynamics and wave theory, often from a beam-plasma perspective. The book begins afresh at chapter 5, which is an ambitious attempt to summarise modern classical dynamics. This chapter begins well, with a nice introduction to action-angle variables (these have already been extensively exploited in the preceding chapters, however!), but the account eventually became too compressed for the present reviewer. There follow two further chapters on both diffusion and the single-wave-particle system. Perhaps this book is best considered as a companion to the research literature (indeed there is a useful and extensive bibliography), rather than as a conventionally structured textbook. Certainly it is a book that should be read backwards and sideways, as well as forwards. Most readers, for example, will be more familiar with the Vlasov-Poisson system than with the N-body approach to particles and fields that is developed here: their natural starting point will perhaps be appendix G.4 of the present volume. Nor does the book provide a free-standing account of plasma dynamics from the chosen perspective. For example, prior familiarity with van Kampen modes in the Vlasov--Poisson description would greatly assist understanding of chapter 3. Challenging exercises are embedded in the text throughout (even in the otherwise excellent appendices), with answers not necessarily provided. Altogether, this book provides a wealth of theoretical information that is not easily accessible from any other source. It is a book with character, written from a definite viewpoint, but it also facilitates the development of the reader's own perspective by offering a clear path to the original research literature. R O Dendy

Superposition Quantification

NASA Astrophysics Data System (ADS)

Chang, Li-Na; Luo, Shun-Long; Sun, Yuan

2017-11-01

The principle of superposition is universal and lies at the heart of quantum theory. Although ever since the inception of quantum mechanics a century ago, superposition has occupied a central and pivotal place, rigorous and systematic studies of the quantification issue have attracted significant interests only in recent years, and many related problems remain to be investigated. In this work we introduce a figure of merit which quantifies superposition from an intuitive and direct perspective, investigate its fundamental properties, connect it to some coherence measures, illustrate it through several examples, and apply it to analyze wave-particle duality. Supported by Science Challenge Project under Grant No. TZ2016002, Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing, Key Laboratory of Random Complex Structures and Data Science, Chinese Academy of Sciences, Grant under No. 2008DP173182

Research briefing on contemporary problems in plasma science

NASA Technical Reports Server (NTRS)

1991-01-01

An overview is presented of the broad perspective of all plasma science. Detailed discussions are given of scientific opportunities in various subdisciplines of plasma science. The first subdiscipline to be discussed is the area where the contemporary applications of plasma science are the most widespread, low temperature plasma science. Opportunities for new research and technology development that have emerged as byproducts of research in magnetic and inertial fusion are then highlighted. Then follows a discussion of new opportunities in ultrafast plasma science opened up by recent developments in laser and particle beam technology. Next, research that uses smaller scale facilities is discussed, first discussing non-neutral plasmas, and then the area of basic plasma experiments. Discussions of analytic theory and computational plasma physics and of space and astrophysical plasma physics are then presented.

Perspectives on individual to ensembles of ambient fine and ultrafine particles and their sources

NASA Astrophysics Data System (ADS)

Bein, Keith James

By combining Rapid Single-ultrafine-particle Mass Spectrometry (RSMS) measurements during the Pittsburgh Supersite experiment with a large array of concurrent PM, gas and meteorological data, a synthesis of data and analyses is employed to characterize sources, emission trends and dynamics of ambient fine and ultrafine particles. Combinatorial analyses elicit individual to ensemble descriptions of particles, their sources, their changes in state from atmospheric processing and the scales of motion driving their transport and dynamics. Major results include (1) Particle size and composition are strong indicators of sources/source categories and real-time measurements allow source attribution at the single particle and point source level. (2) Single particle source attribution compares well to factor analysis of chemically-speciated bulk phase data and both resulted in similar conclusions but independently revealed new sources. (3) RSMS data can quantitatively estimate composition-resolved, number-based particle size distribution. Comparison to mass-based data yielded new information about physical and chemical properties of particles and instrument sensitivity. (4) Source-specific signatures and real-time monitoring allow passing plumes to be tracked and characterized. (5) The largest of three identified coal combustion sources emits ˜ 2.4 x 10 17 primary submicron particles per second. (6) Long-range transport has a significant impact on the eastern U.S. including specific influences of eight separate wildfire events. (7) Pollutant dynamics in the Pittsburgh summertime air shed, and Northeastern U.S., is characterized by alternating periods of stagnation and cleansing. The eight wildfire events were detected in between seven successive stagnation events. (8) Connections exist between boreal fire activity, southeast subsiding transport of the emissions, alternating periods of stagnation and cleansing at the receptor and the structure and propagation of extratropical waves. (9) Wildfire emissions can severely impact preexisting pollutant concentrations and physical and chemical processes at the receptor. (10) High-severity crown fires in boreal Canada emit ˜ 1.2 x 1015 particles/kg biomass burned. (11) In 1998, wildfire activity in the circumpolar boreal forest emitted ˜ 8 x 1026 particles, representing ˜ 14% of global wildland fire emissions. Results and conclusions address future scientific objectives in understanding effects of particles on human health and global climate change.

Critical thinking in physics education

NASA Astrophysics Data System (ADS)

Sadidi, Farahnaz

2016-07-01

We agree that training the next generation of leaders of the society, who have the ability to think critically and form a better judgment is an important goal. It is a long-standing concern of Educators and a long-term desire of teachers to establish a method in order to teach to think critically. To this end, many questions arise on three central aspects: the definition, the evaluation and the design of the course: What is Critical Thinking? How can we define Critical Thinking? How can we evaluate Critical Thinking? Therefore, we want to implement Critical Thinking in physics education. How can we teach for Critical Thinking in physics? What should the course syllabus and materials be? We present examples from classical physics and give perspectives for astro-particle physics. The main aim of this paper is to answer the questions and provide teachers with the opportunity to change their classroom to an active one, in which students are encouraged to ask questions and learn to reach a good judgment. Key words: Critical Thinking, evaluation, judgment, design of the course.

ATLAS Tile Calorimeter calibration and monitoring systems

NASA Astrophysics Data System (ADS)

Cortés-González, Arely

2018-01-01

The ATLAS Tile Calorimeter is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes, located in the outer part of the calorimeter. Neutral particles may also produce a signal after interacting with the material and producing charged particles. The readout is segmented into about 5000 cells, each of them being read out by two photomultipliers in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. This comprises Cesium radioactive sources, Laser, charge injection elements and an integrator based readout system. Information from all systems allows to monitor and equalise the calorimeter response at each stage of the signal production, from scintillation light to digitisation. Calibration runs are monitored from a data quality perspective and used as a cross-check for physics runs. The data quality efficiency achieved during 2016 was 98.9%. These calibration and stability of the calorimeter reported here show that the TileCal performance is within the design requirements and has given essential contribution to reconstructed objects and physics results.

Fundamentals and advances in magnetic hyperthermia

NASA Astrophysics Data System (ADS)

Périgo, E. A.; Hemery, G.; Sandre, O.; Ortega, D.; Garaio, E.; Plazaola, F.; Teran, F. J.

2015-12-01

Nowadays, magnetic hyperthermia constitutes a complementary approach to cancer treatment. The use of magnetic particles as heating mediators, proposed in the 1950s, provides a novel strategy for improving tumor treatment and, consequently, patient's quality of life. This review reports a broad overview about several aspects of magnetic hyperthermia addressing new perspectives and the progress on relevant features such as the ad hoc preparation of magnetic nanoparticles, physical modeling of magnetic heating, methods to determine the heat dissipation power of magnetic colloids including the development of experimental apparatus and the influence of biological matrices on the heating efficiency.

Refined Characterization of Student Perspectives on Quantum Physics

ERIC Educational Resources Information Center

Baily, Charles; Finkelstein, Noah D.

2010-01-01

The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of…

An intuitive two-fluid picture of spontaneous 2D collisionless magnetic reconnection and whistler wave generation

NASA Astrophysics Data System (ADS)

Yoon, Young Dae; Bellan, Paul M.

2018-05-01

An intuitive and physical two-fluid picture of spontaneous 2D collisionless magnetic reconnection and whistler wave generation is presented in the framework of 3D electron-magnetohydrodynamics. In this regime, canonical circulation (Q =me∇×u +qeB ) flux tubes can be defined in analogy to magnetic flux tubes in ideal magnetohydrodynamics. Following the 3D behavior of these Q flux tubes provides a new perspective on collisionless reconnection—a perspective that has been hard to perceive via examinations of 2D projections. This shows that even in a 2D geometry with an ignorable coordinate, a 3D examination is essential for a full comprehension of the process. Intuitive answers are given to three main questions in collisionless reconnection: why is reconnection spontaneous, why do particles accelerate extremely fast, and why are whistler waves generated? Possible extensions to other regimes are discussed.

Inner space/outer space - The interface between cosmology and particle physics

NASA Astrophysics Data System (ADS)

Kolb, Edward W.; Turner, Michael S.; Lindley, David; Olive, Keith; Seckel, David

A collection of papers covering the synthesis between particle physics and cosmology is presented. The general topics addressed include: standard models of particle physics and cosmology; microwave background radiation; origin and evolution of large-scale structure; inflation; massive magnetic monopoles; supersymmetry, supergravity, and quantum gravity; cosmological constraints on particle physics; Kaluza-Klein cosmology; and future directions and connections in particle physics and cosmology.

Relational particle models: I. Reconciliation with standard classical and quantum theory

NASA Astrophysics Data System (ADS)

Anderson, Edward

2006-04-01

This paper concerns the absolute versus relative motion debate. The Barbour and Bertotti (1982) work may be viewed as an indirectly set up relational formulation of a portion of Newtonian mechanics. I consider further direct formulations of this and argue that the portion in question—universes with zero total angular momentum that are conservative and with kinetic terms that are (homogeneous) quadratic in their velocities—is capable of accommodating a wide range of classical physics phenomena. Furthermore, as I develop in paper II, this relational particle model is a useful toy model for canonical general relativity. I consider what happens if one quantizes relational rather than absolute mechanics, indeed whether the latter is misleading. By exploiting Jacobi coordinates, I show how to access many examples of quantized relational particle models and then interpret these from a relational perspective. By these means, previous suggestions of bad semiclassicality for such models can be eluded. I show how small (particle number) universe relational particle model examples display eigenspectrum truncation, gaps, energy interlocking and counterbalanced total angular momentum. These features mean that these small universe models make interesting toy models for some aspects of closed-universe quantum cosmology. Meanwhile, these features do not compromise the recovery of reality as regards the practicalities of experimentation in a large universe such as our own.

Approximate symmetries in atomic nuclei from a large-scale shell-model perspective

NASA Astrophysics Data System (ADS)

Launey, K. D.; Draayer, J. P.; Dytrych, T.; Sun, G.-H.; Dong, S.-H.

2015-05-01

In this paper, we review recent developments that aim to achieve further understanding of the structure of atomic nuclei, by capitalizing on exact symmetries as well as approximate symmetries found to dominate low-lying nuclear states. The findings confirm the essential role played by the Sp(3, ℝ) symplectic symmetry to inform the interaction and the relevant model spaces in nuclear modeling. The significance of the Sp(3, ℝ) symmetry for a description of a quantum system of strongly interacting particles naturally emerges from the physical relevance of its generators, which directly relate to particle momentum and position coordinates, and represent important observables, such as, the many-particle kinetic energy, the monopole operator, the quadrupole moment and the angular momentum. We show that it is imperative that shell-model spaces be expanded well beyond the current limits to accommodate particle excitations that appear critical to enhanced collectivity in heavier systems and to highly-deformed spatial structures, exemplified by the second 0+ state in 12C (the challenging Hoyle state) and 8Be. While such states are presently inaccessible by large-scale no-core shell models, symmetry-based considerations are found to be essential.

Deformation Theory and Physics Model Building

NASA Astrophysics Data System (ADS)

Sternheimer, Daniel

2006-08-01

The mathematical theory of deformations has proved to be a powerful tool in modeling physical reality. We start with a short historical and philosophical review of the context and concentrate this rapid presentation on a few interrelated directions where deformation theory is essential in bringing a new framework - which has then to be developed using adapted tools, some of which come from the deformation aspect. Minkowskian space-time can be deformed into Anti de Sitter, where massless particles become composite (also dynamically): this opens new perspectives in particle physics, at least at the electroweak level, including prediction of new mesons. Nonlinear group representations and covariant field equations, coming from interactions, can be viewed as some deformation of their linear (free) part: recognizing this fact can provide a good framework for treating problems in this area, in particular global solutions. Last but not least, (algebras associated with) classical mechanics (and field theory) on a Poisson phase space can be deformed to (algebras associated with) quantum mechanics (and quantum field theory). That is now a frontier domain in mathematics and theoretical physics called deformation quantization, with multiple ramifications, avatars and connections in both mathematics and physics. These include representation theory, quantum groups (when considering Hopf algebras instead of associative or Lie algebras), noncommutative geometry and manifolds, algebraic geometry, number theory, and of course what is regrouped under the name of M-theory. We shall here look at these from the unifying point of view of deformation theory and refer to a limited number of papers as a starting point for further study.

Topological Classification of Crystalline Insulators through Band Structure Combinatorics

NASA Astrophysics Data System (ADS)

Kruthoff, Jorrit; de Boer, Jan; van Wezel, Jasper; Kane, Charles L.; Slager, Robert-Jan

2017-10-01

We present a method for efficiently enumerating all allowed, topologically distinct, electronic band structures within a given crystal structure in all physically relevant dimensions. The algorithm applies to crystals without time-reversal, particle-hole, chiral, or any other anticommuting or anti-unitary symmetries. The results presented match the mathematical structure underlying the topological classification of these crystals in terms of K -theory and therefore elucidate this abstract mathematical framework from a simple combinatorial perspective. Using a straightforward counting procedure, we classify all allowed topological phases of spinless particles in crystals in class A . Employing this classification, we study transitions between topological phases within class A that are driven by band inversions at high-symmetry points in the first Brillouin zone. This enables us to list all possible types of phase transitions within a given crystal structure and to identify whether or not they give rise to intermediate Weyl semimetallic phases.

Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.

PubMed

Jungmann, Julia H; Heeren, Ron M A

2013-01-15

Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. Copyright © 2012 John Wiley & Sons, Ltd.

Convolution Operations on Coding Metasurface to Reach Flexible and Continuous Controls of Terahertz Beams.

PubMed

Liu, Shuo; Cui, Tie Jun; Zhang, Lei; Xu, Quan; Wang, Qiu; Wan, Xiang; Gu, Jian Qiang; Tang, Wen Xuan; Qing Qi, Mei; Han, Jia Guang; Zhang, Wei Li; Zhou, Xiao Yang; Cheng, Qiang

2016-10-01

The concept of coding metasurface makes a link between physically metamaterial particles and digital codes, and hence it is possible to perform digital signal processing on the coding metasurface to realize unusual physical phenomena. Here, this study presents to perform Fourier operations on coding metasurfaces and proposes a principle called as scattering-pattern shift using the convolution theorem, which allows steering of the scattering pattern to an arbitrarily predesigned direction. Owing to the constant reflection amplitude of coding particles, the required coding pattern can be simply achieved by the modulus of two coding matrices. This study demonstrates that the scattering patterns that are directly calculated from the coding pattern using the Fourier transform have excellent agreements to the numerical simulations based on realistic coding structures, providing an efficient method in optimizing coding patterns to achieve predesigned scattering beams. The most important advantage of this approach over the previous schemes in producing anomalous single-beam scattering is its flexible and continuous controls to arbitrary directions. This work opens a new route to study metamaterial from a fully digital perspective, predicting the possibility of combining conventional theorems in digital signal processing with the coding metasurface to realize more powerful manipulations of electromagnetic waves.

Statistical theory on the analytical form of cloud particle size distributions

NASA Astrophysics Data System (ADS)

Wu, Wei; McFarquhar, Greg

2017-11-01

Several analytical forms of cloud particle size distributions (PSDs) have been used in numerical modeling and remote sensing retrieval studies of clouds and precipitation, including exponential, gamma, lognormal, and Weibull distributions. However, there is no satisfying physical explanation as to why certain distribution forms preferentially occur instead of others. Theoretically, the analytical form of a PSD can be derived by directly solving the general dynamic equation, but no analytical solutions have been found yet. Instead of using a process level approach, the use of the principle of maximum entropy (MaxEnt) for determining the analytical form of PSDs from the perspective of system is examined here. Here, the issue of variability under coordinate transformations that arises using the Gibbs/Shannon definition of entropy is identified, and the use of the concept of relative entropy to avoid these problems is discussed. Focusing on cloud physics, the four-parameter generalized gamma distribution is proposed as the analytical form of a PSD using the principle of maximum (relative) entropy with assumptions on power law relations between state variables, scale invariance and a further constraint on the expectation of one state variable (e.g. bulk water mass). DOE ASR.

Evolution of Theoretical Perspectives in My Research

NASA Astrophysics Data System (ADS)

Otero, Valerie K.

2009-11-01

Over the past 10 years I have been using socio-cultural theoretical perspectives to understand how people learn physics in a highly interactive, inquiry-based physics course such as Physics and Everyday Thinking [1]. As a result of using various perspectives (e.g. Distributed Cognition and Vygotsky's Theory of Concept Formation), my understanding of how these perspectives can be useful for investigating students' learning processes has changed. In this paper, I illustrate changes in my thinking about the role of socio-cultural perspectives in understanding physics learning and describe elements of my thinking that have remained fairly stable. Finally, I will discuss pitfalls in the use of certain perspectives and discuss areas that need attention in theoretical development for PER.

Perspectives in Quantum Physics: Epistemological, Ontological and Pedagogical--An Investigation into Student and Expert Perspectives on the Physical Interpretation of Quantum Mechanics, with Implications for Modern Physics Instruction

ERIC Educational Resources Information Center

Baily, Charles Raymond

2011-01-01

A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our studies suggest this notoriously difficult task may be frustrated by the intuitively "realist" perspectives of introductory…

Atomistic scale nanoscratching behavior of monocrystalline Cu influenced by water film in CMP process

NASA Astrophysics Data System (ADS)

Shi, Junqin; Chen, Juan; Fang, Liang; Sun, Kun; Sun, Jiapeng; Han, Jing

2018-03-01

The effect of water film on the nanoscratching behavior of monocrystalline Cu was studied by molecular dynamics (MD) simulation. The results indicate that the friction force acting on abrasive particle increases due to the resistance of water film accumulating ahead of particle, but the water film with lubrication decreases friction force acting on Cu surface. The accumulation of water molecules around particle causes the anisotropy of ridge and the surface damage around the groove, and the water molecules remaining in the groove lead to the non-regular groove structure. The dislocation evolution displays the re-organization of the dislocation network in the nanoscratching process. The evaluation of removal efficiency shows the number of removed Cu atoms decreases with water film thickness. It is considered that an appropriate rather than a high removal efficiency should be adopted to evaluate the polishing process in real (chemical mechanical polishing) CMP. These results are helpful to reveal the polishing mechanism under the effect of water film from physical perspective, which benefits the development of ultra-precision manufacture and miniaturized components, as well as the innovation of CMP technology.

Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols.

PubMed

Finlayson-Pitts, Barbara J

2009-09-28

While particles have significant deleterious impacts on human health, visibility and climate, quantitative understanding of their formation, composition and fates remains problematic. Indeed, in many cases, even qualitative understanding is lacking. One area of particular uncertainty is the nature of particle surfaces and how this determines interactions with gases in the atmosphere, including water, which is important for cloud formation and properties. The focus in this Perspective article is on some chemistry relevant to airborne particles and especially to reactions occurring on their surfaces. The intent is not to provide a comprehensive review, but rather to highlight a few selected examples of interface chemistry involving inorganic and organic species that may be important in the lower atmosphere. This includes sea salt chemistry, nitrate and nitrite ion photochemistry, organics on surfaces and heterogeneous reactions of oxides of nitrogen on proxies for airborne mineral dust and boundary layer surfaces. Emphasis is on the molecular level understanding that can only be gained by fully integrating experiment and theory to elucidate these complex systems.

Multi-scale analytical investigation of fly ash in concrete

NASA Astrophysics Data System (ADS)

Aboustait, Mohammed B.

Much research has been conducted to find an acceptable concrete ingredient that would act as cement replacement. One promising material is fly ash. Fly ash is a by-product from coal-fired power plants. Throughout this document work on the characterization of fly ash structure and composition will be explored. This effort was conducted through a mixture of cutting edge multi-scale analytical X-ray based techniques that use both bulk experimentation and nano/micro analytical techniques. Furtherly, this examination was coupled by performing Physical/Mechanical ASTM based testing on fly ash-enrolled-concrete to examine the effects of fly ash introduction. The most exotic of the cutting edge characterization techniques endorsed in this work uses the Nano-Computed Tomography and the Nano X-ray Fluorescence at Argonne National Laboratory to investigate single fly ash particles. Additional Work on individual fly ash particles was completed by laboratory-based Micro-Computed Tomography and Scanning Electron Microscopy. By combining the results of individual particles and bulk property tests, a compiled perspective is introduced, and accessed to try and make new insights into the reactivity of fly ash within concrete.

A toolbox for determining subdiffusive mechanisms

NASA Astrophysics Data System (ADS)

Meroz, Yasmine; Sokolov, Igor M.

2015-04-01

Subdiffusive processes have become a field of great interest in the last decades, due to amounting experimental evidence of subdiffusive behavior in complex systems, and especially in biological systems. Different physical scenarios leading to subdiffusion differ in the details of the dynamics. These differences are what allow to theoretically reconstruct the underlying physics from the results of observations, and will be the topic of this review. We review the main statistical analyses available today to distinguish between these scenarios, categorizing them according to the relevant characteristics. We collect the available tools and statistical tests, presenting them within a broader perspective. We also consider possible complications such as the subordination of subdiffusive mechanisms. Due to the advances in single particle tracking experiments in recent years, we focus on the relevant case of where the available experimental data is scant, at the level of single trajectories.

Soft matter perspective on protein crystal assembly.

PubMed

Fusco, Diana; Charbonneau, Patrick

2016-01-01

Crystallography may be the gold standard of protein structure determination, but obtaining the necessary high-quality crystals is also in some ways akin to prospecting for the precious metal. The tools and models developed in soft matter physics to understand colloidal assembly offer some insights into the problem of crystallizing proteins. This topical review describes the various analogies that have been made between proteins and colloids in that context. We highlight the explanatory power of patchy particle models, but also the challenges of providing guidance for crystallizing specific proteins. We conclude with a presentation of possible future research directions. This review is intended for soft matter scientists interested in protein crystallization as a self-assembly problem, and as an introduction to the pertinent physics literature for protein scientists more generally. Copyright © 2015 Elsevier B.V. All rights reserved.

SLAC Library - Online Particle Physics Information

Science.gov Websites

Background Knowledge Particle Physics Lessons and Activities Astronomy and Astrophysics Lessons and Online Particle Physics Information Compiled by Revised: April, 201 7 This annotated list provides a highly selective set of online resources that are useful to the particle physics community. It

Two decades of Mexican particle physics at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy Rubinstein

2002-12-03

This report is a view from Fermilab of Mexican particle physics at the Laboratory since about 1980; it is not intended to be a history of Mexican particle physics: that topic is outside the expertise of the writer. The period 1980 to the present coincides with the growth of Mexican experimental particle physics from essentially no activity to its current state where Mexican groups take part in experiments at several of the world's major laboratories. Soon after becoming Fermilab director in 1979, Leon Lederman initiated a program to encourage experimental physics, especially experimental particle physics, in Latin America. At themore » time, Mexico had significant theoretical particle physics activity, but none in experiment. Following a visit by Lederman to UNAM in 1981, a conference ''Panamerican Symposium on Particle Physics and Technology'' was held in January 1982 at Cocoyoc, Mexico, with about 50 attendees from Europe, North America, and Latin America; these included Lederman, M. Moshinsky, J. Flores, S. Glashow, J. Bjorken, and G. Charpak. Among the conference outcomes were four subsequent similar symposia over the next decade, and a formal Fermilab program to aid Latin American physics (particularly particle physics); it also influenced a decision by Mexican physicist Clicerio Avilez to switch from theoretical to experimental particle physics. The first physics collaboration between Fermilab and Mexico was in particle theory. Post-docs Rodrigo Huerta and Jose Luis Lucio spent 1-2 years at Fermilab starting in 1981, and other theorists (including Augusto Garcia, Arnulfo Zepeda, Matias Moreno and Miguel Angel Perez) also spent time at the Laboratory in the 1980s.« less

Stochastic Processes in Physics: Deterministic Origins and Control

NASA Astrophysics Data System (ADS)

Demers, Jeffery

Stochastic processes are ubiquitous in the physical sciences and engineering. While often used to model imperfections and experimental uncertainties in the macroscopic world, stochastic processes can attain deeper physical significance when used to model the seemingly random and chaotic nature of the underlying microscopic world. Nowhere more prevalent is this notion than in the field of stochastic thermodynamics - a modern systematic framework used describe mesoscale systems in strongly fluctuating thermal environments which has revolutionized our understanding of, for example, molecular motors, DNA replication, far-from equilibrium systems, and the laws of macroscopic thermodynamics as they apply to the mesoscopic world. With progress, however, come further challenges and deeper questions, most notably in the thermodynamics of information processing and feedback control. Here it is becoming increasingly apparent that, due to divergences and subtleties of interpretation, the deterministic foundations of the stochastic processes themselves must be explored and understood. This thesis presents a survey of stochastic processes in physical systems, the deterministic origins of their emergence, and the subtleties associated with controlling them. First, we study time-dependent billiards in the quivering limit - a limit where a billiard system is indistinguishable from a stochastic system, and where the simplified stochastic system allows us to view issues associated with deterministic time-dependent billiards in a new light and address some long-standing problems. Then, we embark on an exploration of the deterministic microscopic Hamiltonian foundations of non-equilibrium thermodynamics, and we find that important results from mesoscopic stochastic thermodynamics have simple microscopic origins which would not be apparent without the benefit of both the micro and meso perspectives. Finally, we study the problem of stabilizing a stochastic Brownian particle with feedback control, and we find that in order to avoid paradoxes involving the first law of thermodynamics, we need a model for the fine details of the thermal driving noise. The underlying theme of this thesis is the argument that the deterministic microscopic perspective and stochastic mesoscopic perspective are both important and useful, and when used together, we can more deeply and satisfyingly understand the physics occurring over either scale.

A fluid modeling perspective on the tokamak power scrape-off width using SOLPS-ITER

NASA Astrophysics Data System (ADS)

Meier, Eric

2016-10-01

SOLPS-ITER, a 2D fluid code, is used to conduct the first fluid modeling study of the physics behind the power scrape-off width (λq). When drift physics are activated in the code, λq is insensitive to changes in toroidal magnetic field (Bt), as predicted by the 0D heuristic drift (HD) model developed by Goldston. Using the HD model, which quantitatively agrees with regression analysis of a multi-tokamak database, λq in ITER is projected to be 1 mm instead of the previously assumed 4 mm, magnifying the challenge of maintaining the peak divertor target heat flux below the technological limit. These simulations, which use DIII-D H-mode experimental conditions as input, and reproduce the observed high-recycling, attached outer target plasma, allow insights into the scrape-off layer (SOL) physics that set λq. Independence of λq with respect to Bt suggests that SOLPS-ITER captures basic HD physics: the effect of Bt on the particle dwell time ( Bt) cancels with the effect on drift speed ( 1 /Bt), fixing the SOL plasma density width, and dictating λq. Scaling with plasma current (Ip), however, is much weaker than the roughly 1 /Ip dependence predicted by the HD model. Simulated net cross-separatrix particle flux due to magnetic drifts exceeds the anomalous particle transport, and a Pfirsch-Schluter-like SOL flow pattern is established. Up-down ion pressure asymmetry enables the net magnetic drift flux. Drifts establish in-out temperature asymmetry, and an associated thermoelectric current carries significant heat flux to the outer target. The density fall-off length in the SOL is similar to the electron temperature fall-off length, as observed experimentally. Finally, opportunities and challenges foreseen in ongoing work to extrapolate SOLPS-ITER and the HD model to ITER and future machines will be discussed. Supported by U.S. Department of Energy Contract DESC0010434.

A Journey Through the Universe at the Deutsches Museum

NASA Astrophysics Data System (ADS)

Wankerl, B.

2010-12-01

Five research institutions in Munich and Garching bei München joined forces in the International Year of Astronomy 2009 to realise a unique exhibition project at the Deutsches Museum. The exhibition is called Evolution of the Universe and invites visitors to take a tour through time, beginning 13.7 billion years ago with the Big Bang and finishing with a glimpse into the future of the Universe. En route visitors learn how space, time, matter and the large structures in space have formed. The exhibition combines findings from astronomy, astrophysics, nuclear and particle physics in order to present the history of cosmos from different perspectives.

The Microstructural Design of Trimodal Aluminum Composites

NASA Astrophysics Data System (ADS)

Jiang, Lin; Ma, Kaka; Yang, Hanry; Li, Meijuan; Lavernia, Enrique J.; Schoenung, Julie M.

2014-06-01

Trimodal composites, consisting of nanocrystalline or ultrafine grains (UFGs), coarse grains (CGs), and ceramic particles, were originally formulated to achieve combinations of physical and mechanical properties that are unattainable with the individual phases, such as strength, ductility, and high-strain-rate deformation. The concept of a trimodal structure is both scientifically novel as well as technologically promising because it provides multiple controllable degrees of freedom that allow for extensive microstructure design. The UFGs provide efficient obstacles for dislocation movement, such as grain boundaries and other crystalline defects. The size, distribution, and spatial arrangement of the CGs can be controlled to provide plasticity during deformation. The size, morphology, and distribution of the reinforcement particles can be tailored to attain various engineering and physical properties. Moreover, the interfaces that form among the various phases also help determine the overall behavior of the trimodal composites. In this article, a review is provided to discuss the selection and design of each component in trimodal Al composites. The toughening and strengthening mechanisms in the trimodal composite structure are discussed, paying particular attention to strategies that can be implemented to tailor microstructures for optimal mechanical behavior. Recent results obtained with high-performance trimodal Al composites that contain nanometric reinforcements are also discussed to highlight the ability to control particle-matrix interface characteristics. Finally, a perspective is provided on potential approaches that can be explored to develop the next generation of trimodal composites, and interesting scientific paradigms that evolve from the proposed design strategies are discussed.

Inquiring Minds

Science.gov Websites

Go Science at Fermilab Fermilab and the Higgs Boson Frontiers of Particle Physics Experiments & Answers Submit a Question Frontiers of Particle Physics Benefits to Society Benefits to Society Medicine Inquiring Minds Questions About Physics Other High-Energy Physics Sites More About Particle Physics Library

Planetary Rings

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.

1994-01-01

Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

Physics of Alfvén waves and energetic particles in burning plasmas

NASA Astrophysics Data System (ADS)

Chen, Liu; Zonca, Fulvio

2016-01-01

Dynamics of shear Alfvén waves and energetic particles are crucial to the performance of burning fusion plasmas. This article reviews linear as well as nonlinear physics of shear Alfvén waves and their self-consistent interaction with energetic particles in tokamak fusion devices. More specifically, the review on the linear physics deals with wave spectral properties and collective excitations by energetic particles via wave-particle resonances. The nonlinear physics deals with nonlinear wave-wave interactions as well as nonlinear wave-energetic particle interactions. Both linear as well as nonlinear physics demonstrate the qualitatively important roles played by realistic equilibrium nonuniformities, magnetic field geometries, and the specific radial mode structures in determining the instability evolution, saturation, and, ultimately, energetic-particle transport. These topics are presented within a single unified theoretical framework, where experimental observations and numerical simulation results are referred to elucidate concepts and physics processes.

Time Perspective and Physical Activity among Central Appalachian Adolescents

ERIC Educational Resources Information Center

Gulley, Tauna

2013-01-01

Time perspective is a cultural behavioral concept that reflects individuals' orientations or attitudes toward the past, present, or future. Individuals' time perspectives influence their choices regarding daily activities. Time perspective is an important consideration when teaching adolescents about the importance of being physically active.…

Classical many-particle systems with unique disordered ground states

NASA Astrophysics Data System (ADS)

Zhang, G.; Stillinger, F. H.; Torquato, S.

2017-10-01

Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016), 10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.

Fermilab | Science at Fermilab | Experiments & Projects | Energy Frontier

Science.gov Websites

Go Science at Fermilab Fermilab and the Higgs Boson Frontiers of Particle Physics Experiments & Answers Submit a Question Frontiers of Particle Physics Benefits to Society Benefits to Society Medicine Inquiring Minds Questions About Physics Other High-Energy Physics Sites More About Particle Physics Library

Fermilab | Science at Fermilab | Experiments & Projects

Science.gov Websites

Go Science at Fermilab Fermilab and the Higgs Boson Frontiers of Particle Physics Experiments & Answers Submit a Question Frontiers of Particle Physics Benefits to Society Benefits to Society Medicine Inquiring Minds Questions About Physics Other High-Energy Physics Sites More About Particle Physics Library

Nuclear and Particle Physics, Astrophysics and Cosmology : T-2 : LANL

Science.gov Websites

linked in Search T-2, Nuclear and Particle Physics, Astrophysics and Cosmology T-2 Home T Division Focus Areas Nuclear Information Service Nuclear Physics Particle Physics Astrophysics Cosmology CONTACTS Group energy security, heavy ion physics, nuclear astrophysics, physics beyond the standard model, neutrino

Nuclear-Structure Physics with MINIBALL at HIE-ISOLDE

NASA Astrophysics Data System (ADS)

Reiter, P.; MINIBALL Collaboration

2018-02-01

The MINIBALL spectrometer utilizes successfully a variety of post-accelerated radioactive ion beams provided by the new HIE-ISOLDE accelerator at CERN. In-beam γ-ray spectroscopy after Coulomb excitation (CE) or transfer reactions is performed with optimized setups of ancillary detectors for particle detection. The physics program covers a wide range of shell model investigations. Exotic heavy ion beams will enable unique studies of collective properties up to the actinide region. First data taking with HIE-ISOLDE beams started recently. The higher energies and intensities of the new post-accelerator provides a promising perspective for a new generation of MINIBALL experiments. Intriguing first results were obtained by employing beams of 74,76,78Zn, 110,132Sn, 144Xe with beam energies in the range of 4.0 - 5.5 MeV/u for CE experiments at ‘safe’ energies. In all cases first results for various B(Eλ) values for these isotopes were obtained.

Particle astrophysics

NASA Technical Reports Server (NTRS)

Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

1991-01-01

The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

Feynman-diagrams approach to the quantum Rabi model for ultrastrong cavity QED: stimulated emission and reabsorption of virtual particles dressing a physical excitation

NASA Astrophysics Data System (ADS)

Di Stefano, Omar; Stassi, Roberto; Garziano, Luigi; Frisk Kockum, Anton; Savasta, Salvatore; Nori, Franco

2017-05-01

In quantum field theory, bare particles are dressed by a cloud of virtual particles to form physical particles. The virtual particles affect properties such as the mass and charge of the physical particles, and it is only these modified properties that can be measured in experiments, not the properties of the bare particles. The influence of virtual particles is prominent in the ultrastrong-coupling regime of cavity quantum electrodynamics (QED), which has recently been realised in several condensed-matter systems. In some of these systems, the effective interaction between atom-like transitions and the cavity photons can be switched on or off by external control pulses. This offers unprecedented possibilities for exploring quantum vacuum fluctuations and the relation between physical and bare particles. We consider a single three-level quantum system coupled to an optical resonator. Here we show that, by applying external electromagnetic pulses of suitable amplitude and frequency, each virtual photon dressing a physical excitation in cavity-QED systems can be converted into a physical observable photon, and back again. In this way, the hidden relationship between the bare and the physical excitations can be unravelled and becomes experimentally testable. The conversion between virtual and physical photons can be clearly pictured using Feynman diagrams with cut loops.

Health effects of atmospheric particulates: a medical geology perspective.

PubMed

Duzgoren-Aydin, Nurdan S

2008-01-01

In this review, atmospheric particulates as composite airborne earth materials often containing both natural and anthropogenic components were examined in the context of medical geology. Despite a vast number of both experimental and epidemiological studies confirming the direct and indirect links between atmospheric particulates and human health, the exact nature of mechanisms affecting the particulate-induced pathogenesis largely remains unexplored. Future in depth research on these areas would be most successful if potential mechanisms are examined with reference to the physical (e.g., size, shape and surface), chemical, mineralogical and source characteristics of particulate matters. The underlying goal of this review was to present the relevant terminology and processes proposed in the literature to explain the interfaces and interactions between atmospheric particles and human body within the framework of "atmospheric particle cycles." The complexities of the interactions were demonstrated through case studies focusing on particulate matter air pollution and malignant mesothelioma occurrences due to environmental exposure to erionite-a fibrous zeolite mineral. There is an urgent need for a standard protocol or speciation methods applicable to earth-materials to guide and streamline studies on etiology of mineral-induced diseases. This protocol or speciation methods should provide relevant procedures to determine the level and extent of physical, chemical and mineralogical heterogeneity of particulate matters as well as quantitative in-situ particulate characteristics.

Fermilab | Science at Fermilab | Experiments & Projects | Intensity

Science.gov Websites

Search Search Go Science at Fermilab Fermilab and the Higgs Boson Frontiers of Particle Physics and Answers Submit a Question Frontiers of Particle Physics Benefits to Society Benefits to Society Results Inquiring Minds Questions About Physics Other High-Energy Physics Sites More About Particle

Applications of Nuclear and Particle Physics Technology: Particles & Detection — A Brief Overview

NASA Astrophysics Data System (ADS)

Weisenberger, Andrew G.

A brief overview of the technology applications with significant societal benefit that have their origins in nuclear and particle physics research is presented. It is shown through representative examples that applications of nuclear physics can be classified into two basic areas: 1) applying the results of experimental nuclear physics and 2) applying the tools of experimental nuclear physics. Examples of the application of the tools of experimental nuclear and particle physics research are provided in the fields of accelerator and detector based technologies namely synchrotron light sources, nuclear medicine, ion implantation and radiation therapy.

The contribution of medical physics to nuclear medicine: a physician's perspective.

PubMed

Ell, Peter J

2014-12-01

This paper is the second in a series of invited perspectives by four pioneers of nuclear medicine imaging and physics. A medical physicist and a nuclear medicine clinical specialist each take a backward look and a forward look at the contributions of physics to nuclear medicine. Here is a backward look from a nuclear medicine physician's perspective.

Particle Accelerators Test Cosmological Theory.

ERIC Educational Resources Information Center

Schramm, David N.; Steigman, Gary

1988-01-01

Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)

An Evaluation of the Particle Physics Masterclass as a Context for Student Learning about the Nature of Science

ERIC Educational Resources Information Center

Wadness, Michael J.

2010-01-01

This dissertation addresses the research question: To what extent do secondary school science students attending the U.S. Particle Physics Masterclass change their view of the nature of science (NOS)? The U.S. Particle Physics Masterclass is a physics outreach program run by QuarkNet, a national organization of secondary school physics teachers…

Trojan horse particle invariance: The impact on nuclear astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pizzone, R. G.; La Cognata, M.; Spitaleri, C.

In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previousmore » studies will be extended to the cases of the binary d(d, p)t and {sup 6}Li(d,α){sup 4}He reactions, which were tested using different quasi-free break-up's, namely {sup 6}Li and {sup 3}He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions.« less

A new fast scanning system for the measurement of large angle tracks in nuclear emulsions

NASA Astrophysics Data System (ADS)

Alexandrov, A.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Galati, G.; Lauria, A.; Montesi, M. C.; Pupilli, F.; Shchedrina, T.; Tioukov, V.; Vladymyrov, M.

2015-11-01

Nuclear emulsions have been widely used in particle physics to identify new particles through the observation of their decays thanks to their unique spatial resolution. Nevertheless, before the advent of automatic scanning systems, the emulsion analysis was very demanding in terms of well trained manpower. Due to this reason, they were gradually replaced by electronic detectors, until the '90s, when automatic microscopes started to be developed in Japan and in Europe. Automatic scanning was essential to conceive large scale emulsion-based neutrino experiments like CHORUS, DONUT and OPERA. Standard scanning systems have been initially designed to recognize tracks within a limited angular acceptance (θ lesssim 30°) where θ is the track angle with respect to a line perpendicular to the emulsion plane. In this paper we describe the implementation of a novel fast automatic scanning system aimed at extending the track recognition to the full angular range and improving the present scanning speed. Indeed, nuclear emulsions do not have any intrinsic limit to detect particle direction. Such improvement opens new perspectives to use nuclear emulsions in several fields in addition to large scale neutrino experiments, like muon radiography, medical applications and dark matter directional detection.

Controllable surface haptics via particle jamming and pneumatics.

PubMed

Stanley, Andrew A; Okamura, Allison M

2015-01-01

The combination of particle jamming and pneumatics allows the simultaneous control of shape and mechanical properties in a tactile display. A hollow silicone membrane is molded into an array of thin cells, each filled with coffee grounds such that adjusting the vacuum level in any individual cell rapidly switches it between flexible and rigid states. The array clamps over a pressure-regulated air chamber with internal mechanisms designed to pin the nodes between cells at any given height. Various sequences of cell vacuuming, node pinning, and chamber pressurization allow the surface to balloon into a variety of shapes. Experiments were performed to expand existing physical models of jamming at the inter-particle level to define the rheological characteristics of jammed systems from a macroscopic perspective, relevant to force-displacement interactions that would be experienced by human users. Force-displacement data show that a jammed cell in compression fits a Maxwell model and a cell deflected in the center while supported only at the edges fits a Zener model, each with stiffness and damping parameters that increase at higher levels of applied vacuum. This provides framework to tune and control the mechanical properties of a jamming haptic interface.

The influence of human physical activity and contaminated clothing type on particle resuspension.

PubMed

McDonagh, A; Byrne, M A

2014-01-01

A study was conducted to experimentally quantify the influence of three variables on the level of resuspension of hazardous aerosol particles from clothing. Variables investigated include physical activity level (two levels, low and high), surface type (four different clothing material types), and time i.e. the rate at which particles resuspend. A mixture of three monodisperse tracer-labelled powders, with median diameters of 3, 5, and 10 microns, was used to "contaminate" the samples, and the resuspended particles were analysed in real-time using an Aerodynamic Particle Sizer (APS), and also by Neutron Activation Analysis (NAA). The overall finding was that physical activity resulted in up to 67% of the contamination deposited on clothing being resuspended back into the air. A detailed examination of the influence of physical activity level on resuspension, from NAA, revealed that the average resuspended fraction (RF) of particles at low physical activity was 28 ± 8%, and at high physical activity was 30 ± 7%, while the APS data revealed a tenfold increase in the cumulative mass of airborne particles during high physical activity in comparison to that during low physical activity. The results also suggest that it is not the contaminated clothing's fibre type which influences particle resuspension, but the material's weave pattern (and hence the material's surface texture). Investigation of the time variation in resuspended particle concentrations indicated that the data were separable into two distinct regimes: the first (occurring within the first 1.5 min) having a high, positive rate of change of airborne particle concentration relative to the second regime. The second regime revealed a slower rate of change of particle concentration and remained relatively unchanged for the remainder of each resuspension event. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficient high-quality volume rendering of SPH data.

PubMed

Fraedrich, Roland; Auer, Stefan; Westermann, Rüdiger

2010-01-01

High quality volume rendering of SPH data requires a complex order-dependent resampling of particle quantities along the view rays. In this paper we present an efficient approach to perform this task using a novel view-space discretization of the simulation domain. Our method draws upon recent work on GPU-based particle voxelization for the efficient resampling of particles into uniform grids. We propose a new technique that leverages a perspective grid to adaptively discretize the view-volume, giving rise to a continuous level-of-detail sampling structure and reducing memory requirements compared to a uniform grid. In combination with a level-of-detail representation of the particle set, the perspective grid allows effectively reducing the amount of primitives to be processed at run-time. We demonstrate the quality and performance of our method for the rendering of fluid and gas dynamics SPH simulations consisting of many millions of particles.

The extent of visual space inferred from perspective angles

PubMed Central

Erkelens, Casper J.

2015-01-01

Retinal images are perspective projections of the visual environment. Perspective projections do not explain why we perceive perspective in 3-D space. Analysis of underlying spatial transformations shows that visual space is a perspective transformation of physical space if parallel lines in physical space vanish at finite distance in visual space. Perspective angles, i.e., the angle perceived between parallel lines in physical space, were estimated for rails of a straight railway track. Perspective angles were also estimated from pictures taken from the same point of view. Perspective angles between rails ranged from 27% to 83% of their angular size in the retinal image. Perspective angles prescribe the distance of vanishing points of visual space. All computed distances were shorter than 6 m. The shallow depth of a hypothetical space inferred from perspective angles does not match the depth of visual space, as it is perceived. Incongruity between the perceived shape of a railway line on the one hand and the experienced ratio between width and length of the line on the other hand is huge, but apparently so unobtrusive that it has remained unnoticed. The incompatibility between perspective angles and perceived distances casts doubt on evidence for a curved visual space that has been presented in the literature and was obtained from combining judgments of distances and angles with physical positions. PMID:26034567

Non-Brownian diffusion in lipid membranes: Experiments and simulations.

PubMed

Metzler, R; Jeon, J-H; Cherstvy, A G

2016-10-01

The dynamics of constituents and the surface response of cellular membranes-also in connection to the binding of various particles and macromolecules to the membrane-are still a matter of controversy in the membrane biophysics community, particularly with respect to crowded membranes of living biological cells. We here put into perspective recent single particle tracking experiments in the plasma membranes of living cells and supercomputing studies of lipid bilayer model membranes with and without protein crowding. Special emphasis is put on the observation of anomalous, non-Brownian diffusion of both lipid molecules and proteins embedded in the lipid bilayer. While single component, pure lipid bilayers in simulations exhibit only transient anomalous diffusion of lipid molecules on nanosecond time scales, the persistence of anomalous diffusion becomes significantly longer ranged on the addition of disorder-through the addition of cholesterol or proteins-and on passing of the membrane lipids to the gel phase. Concurrently, experiments demonstrate the anomalous diffusion of membrane embedded proteins up to macroscopic time scales in the minute time range. Particular emphasis will be put on the physical character of the anomalous diffusion, in particular, the occurrence of ageing observed in the experiments-the effective diffusivity of the measured particles is a decreasing function of time. Moreover, we present results for the time dependent local scaling exponent of the mean squared displacement of the monitored particles. Recent results finding deviations from the commonly assumed Gaussian diffusion patterns in protein crowded membranes are reported. The properties of the displacement autocorrelation function of the lipid molecules are discussed in the light of their appropriate physical anomalous diffusion models, both for non-crowded and crowded membranes. In the last part of this review we address the upcoming field of membrane distortion by elongated membrane-binding particles. We discuss how membrane compartmentalisation and the particle-membrane binding energy may impact the dynamics and response of lipid membranes. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

What's Next for Particle Physics?

NASA Astrophysics Data System (ADS)

White, Martin

2017-10-01

Following the discovery of the Higgs boson in 2012, particle physics has entered its most exciting and crucial period for over 50 years. In this book, I first summarise our current understanding of particle physics, and why this knowledge is almost certainly incomplete. We will then see that the Large Hadron Collider provides the means to search for the next theory of particle physics by performing precise measurements of the Higgs boson, and by looking directly for particles that can solve current cosmic mysteries such as the nature of dark matter. Finally, I will anticipate the next decade of particle physics by placing the Large Hadron Collider within the wider context of other experiments. The results expected over the next ten years promise to transform our understanding of what the Universe is made of and how it came to be.

PREFACE: Prospects in Neutrino Physics 2013 - NuPhys2013

NASA Astrophysics Data System (ADS)

2015-04-01

The first "Prospects in Neutrino Physics 2013 - NuPhys2013" conference was held at the Institute of Physics, IoP, London, 19-20 December 2013 and was attended by about 130 delegates from institutions worldwide. Lunch and coffee breaks allowed discussions among delegates and speakers to take place in an informal setting. This conference is unique in discussing the worldwide strategy to address unresolved issues in neutrino physics, and shape the future directions of particle physics. We discussed the current status and focussed especially on the prospects of future experiments, their performance and physics reach. It is particularly timely due to the recent measurements in neutrino physics and planned worldwide experiments. The following topics were addressed: • Theory and Phenomenology Perspectives • Future Long and Short Baseline Neutrino Oscillation Experiments • Reactor neutrino and flux • Neutrinoless double beta decays • Solar, atmospheric, supernova neutrinos • Neutrino cosmology in which both the phenomenological and experimental aspects were equally addressed. World-leading experts in the different neutrino areas were invited to give review talks. To encourage and facilitate the participation of early-career researchers and PhD students, a poster session formed a key aspect of this meeting. The conference was organized by Francesca Di Lodovico and Silvia Pascoli. It was sponsored by the IoP through their Topic Research Meeting Grant, and also supported by Durham IPPP, ERC-207282, FP7 invisibles project, Queen Mary University of London.

Links between personality, time perspective, and intention to practice physical activity during cancer treatment: an exploratory study.

PubMed

Villaron, Charlène; Marqueste, Tanguy; Eisinger, François; Cappiello, Maria-Antonietta; Therme, Pierre; Cury, François

2017-04-01

The purpose of the study was to analyze links between personality, time perspective, and intention to practice physical activity during cancer treatment. One hundred forty-three patients participated in survey by questionnaire. Intention to practice physical activity, time perspective using Zimbardo Time Perspective Inventory, and personality with the Big Five Inventory were measured. Structural equation models using Lisrel were developed to examine hypothetical links between the variables. The adjusted model evidenced an excellent fit (comparative fit index = 0.92; root-mean-square error of approximation = 0.076; P = .014). Results showed that intention to practice exercise was positively linked with openness to experience and negatively with present fatalist time perspective. Moreover, conscientiousness and neuroticism were found to be linked with future time perspective, which was positively related with intention to practice physical activity. The present exploratory study with patients suffering from cancer underlined the importance of considering jointly time perspective dimensions and personality factors for health behavior recommendations. Based on our results, we propose some reflections on practice to help nurses and physicians increase patient's motivation to be physically active. Taking into account patients' personality and time perspective, we would be able to propose specific awareness messages and offer short interventions to have an impact on patients' motivation to practice. Copyright © 2016 John Wiley & Sons, Ltd.

Test on the effectiveness of the sum over paths approach in favoring the construction of an integrated knowledge of quantum physics in high school

NASA Astrophysics Data System (ADS)

Malgieri, Massimiliano; Onorato, Pasquale; De Ambrosis, Anna

2017-06-01

In this paper we present the results of a research-based teaching-learning sequence on introductory quantum physics based on Feynman's sum over paths approach in the Italian high school. Our study focuses on students' understanding of two founding ideas of quantum physics, wave particle duality and the uncertainty principle. In view of recent research reporting the fragmentation of students' mental models of quantum concepts after initial instruction, we collected and analyzed data using the assessment tools provided by knowledge integration theory. Our results on the group of n =14 students who performed the final test indicate that the functional explanation of wave particle duality provided by the sum over paths approach may be effective in leading students to build consistent mental models of quantum objects, and in providing them with a unified perspective on both the photon and the electron. Results on the uncertainty principle are less clear cut, as the improvements over traditional instruction appear less significant. Given the low number of students in the sample, this work should be interpreted as a case study, and we do not attempt to draw definitive conclusions. However, our study suggests that (i) the sum over paths approach may deserve more attention from researchers and educators as a possible route to introduce basic concepts of quantum physics in high school, and (ii) more research should be focused not only on the correctness of students' mental models on individual concepts, but also on the ability of students to connect different ideas and experiments related to quantum theory in an organized whole.

The Influences on Teaching Perspectives of Australian Physical Education Teacher Education Students: The First-Year Influences on Teaching Perspectives Exploratory (FIT-PE) Study

ERIC Educational Resources Information Center

Hyndman, Brendon P.; Pill, Shane

2016-01-01

There has been a paucity of literature investigating the teaching beliefs and intentions of Australian physical education teacher education (PETE) students that enter teacher training. The First-year Influences on Teaching Perspectives Exploratory (FIT-PE) study explores the teaching perspectives of first year PETE students; including teaching…

Micro- to macroscale perspectives on space plasmas

NASA Technical Reports Server (NTRS)

Eastman, Timothy E.

1993-01-01

The Earth's magnetosphere is the most accessible of natural collisionless plasma environments; an astrophysical plasma 'laboratory'. Magnetospheric physics has been in an exploration phase since its origin 35 years ago but new coordinated, multipoint observations, theory, modeling, and simulations are moving this highly interdisciplinary field of plasma science into a new phase of synthesis and understanding. Plasma systems are ones in which binary collisions are relatively negligible and collective behavior beyond the microscale emerges. Most readily accessible natural plasma systems are collisional and nearest-neighbor classical interactions compete with longer-range plasma effects. Except for stars, most space plasmas are collisionless, however, and the effects of electrodynamic coupling dominate. Basic physical processes in such collisionless plasmas occur at micro-, meso-, and macroscales that are not merely reducible to each other in certain crucial ways as illustrated for the global coupling of the Earth's magnetosphere and for the nonlinear dynamics of charged particle motion in the magnetotail. Such global coupling and coherence makes the geospace environment, the domain of solar-terrestrial science, the most highly coupled of all physical geospheres.

Acceleration, Transport, Forecasting and Impact of solar energetic particles in the framework of the 'HESPERIA' HORIZON 2020 project

NASA Astrophysics Data System (ADS)

Malandraki, Olga; Klein, Karl-Ludwig; Vainio, Rami; Agueda, Neus; Nunez, Marlon; Heber, Bernd; Buetikofer, Rolf; Sarlanis, Christos; Crosby, Norma

2017-04-01

High-energy solar energetic particles (SEPs) emitted from the Sun are a major space weather hazard motivating the development of predictive capabilities. In this work, the current state of knowledge on the origin and forecasting of SEP events will be reviewed. Subsequently, we will present the EU HORIZON2020 HESPERIA (High Energy Solar Particle Events foRecastIng and Analysis) project, its structure, its main scientific objectives and forecasting operational tools, as well as the added value to SEP research both from the observational as well as the SEP modelling perspective. The project addresses through multi-frequency observations and simulations the chain of processes from particle acceleration in the corona, particle transport in the magnetically complex corona and interplanetary space to the detection near 1 AU. Furthermore, publicly available software to invert neutron monitor observations of relativistic SEPs to physical parameters that can be compared with space-borne measurements at lower energies is provided for the first time by HESPERIA. In order to achieve these goals, HESPERIA is exploiting already available large datasets stored in databases such as the neutron monitor database (NMDB) and SEPServer that were developed under EU FP7 projects from 2008 to 2013. Forecasting results of the two novel SEP operational forecasting tools published via the consortium server of 'HESPERIA' will be presented, as well as some scientific key results on the acceleration, transport and impact on Earth of high-energy particles. Acknowledgement: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

Middle School Physical Education Teachers' Perspectives on Overweight Students

ERIC Educational Resources Information Center

Doolittle, Sarah A.; Rukavina, Paul B.; Li, Weidong; Manson, Mara; Beale, Angela

2016-01-01

Using the Social Ecological Constraints model, a qualitative multiple case study design was used to explore experienced and committed middle school physical education teachers' perspectives on overweight and obese students (OWS), and how and why they acted to include OWS in physical education and physical activity opportunities in their school…

Particle Physics: From School to University.

ERIC Educational Resources Information Center

Barlow, Roger

1992-01-01

Discusses the teaching of particle physics as part of the A-level physics course in British secondary schools. Utilizes the quark model of hadrons and the conceptual kinematics of particle collisions, as examples, to demonstrate practical instructional possibilities in relation to student expectations. (JJK)

Shear thickening in suspensions: the lubricated-to-frictional contact scenario

NASA Astrophysics Data System (ADS)

Morris, Jeffrey

2017-11-01

Suspensions of solid particles in viscous liquids can vary from low-viscosity liquids to wet granular materials or soft solids depending on the solids loading and the forces acting between particles. When the particles are very concentrated, these mixtures are ''dense suspensions.'' Dense suspensions often exhibit shear thickening, an increase in apparent viscosity as the shear rate is increased. In its most extreme form, order of magnitude increases in viscosity over such a narrow range in shear rate occur that the term discontinuous shear thickening (DST) is applied. DST is particularly striking as it occurs in the relatively simple case of nearly hard spheres in a Newtonian liquid, and is found to take place for submicron particles in colloidal dispersions to much larger particle corn starch dispersions. We focus on simulations of a recently developed ``lubricated-to-frictional'' rheology in which the interplay of viscous lubrication, repulsive surface forces, and contact friction between particle surfaces provides a scenario to explain DST. Our simulation method brings together elements of the discrete-element method from granular flow with a simplified Stokesian Dynamics, and can rationalize not only the abrupt change in properties with imposed shear rate (or shear stress), but also the magnitude of the change. The large change in properties is associated with the breakdown of lubricating films between particles, with activation of Coulomb friction between particles. The rate dependence is caused by the shearing forces driving particles to contact, overwhelming conservative repulsive forces between surfaces; the repulsive forces are representative of colloidal stabilization by surface charge or steric effects, e.g. due to adsorbed polymer. The results of simulation are compared to developments by other groups, including a number of experimental studies and a theory incorporating the same basic elements as the simulation. The comparison to experiments of the predictions of the lubricated-to-frictional rheology is generally good, but discrepancies demand some perspective on the strong simplifying assumptions in the model. Since contact is difficult to both establish and to characterize for surfaces between particles of micron scale or smaller, what is happening in the very close ``contacts'' is not clear, and how changes at this scale give rise to the large-scale force organization is yet to be established. The insight to the elements needed for the abrupt flow induced transition seen in DST thus suggests a need for consideration of both the microscopic physics of contact and the statistical physics governing the macroscopic properties. This work was supported in part by the NSF CBET program, Grant # 1605283.

From Particle Physics to Medical Applications

NASA Astrophysics Data System (ADS)

Dosanjh, Manjit

2017-06-01

CERN is the world's largest particle physics research laboratory. Since it was established in 1954, it has made an outstanding contribution to our understanding of the fundamental particles and their interactions, and also to the technologies needed to analyse their properties and behaviour. The experimental challenges have pushed the performance of particle accelerators and detectors to the limits of our technical capabilities, and these groundbreaking technologies can also have a significant impact in applications beyond particle physics. In particular, the detectors developed for particle physics have led to improved techniques for medical imaging, while accelerator technologies lie at the heart of the irradiation methods that are widely used for treating cancer. Indeed, many important diagnostic and therapeutic techniques used by healthcare professionals are based either on basic physics principles or the technologies developed to carry out physics research. Ever since the discovery of x-rays by Roentgen in 1895, physics has been instrumental in the development of technologies in the biomedical domain, including the use of ionizing radiation for medical imaging and therapy. Some key examples that are explored in detail in this book include scanners based on positron emission tomography, as well as radiation therapy for cancer treatment. Even the collaborative model of particle physics is proving to be effective in catalysing multidisciplinary research for medical applications, ensuring that pioneering physics research is exploited for the benefit of all.

Let’s have a coffee with the Standard Model of particle physics!

NASA Astrophysics Data System (ADS)

Woithe, Julia; Wiener, Gerfried J.; Van der Veken, Frederik F.

2017-05-01

The Standard Model of particle physics is one of the most successful theories in physics and describes the fundamental interactions between elementary particles. It is encoded in a compact description, the so-called ‘Lagrangian’, which even fits on t-shirts and coffee mugs. This mathematical formulation, however, is complex and only rarely makes it into the physics classroom. Therefore, to support high school teachers in their challenging endeavour of introducing particle physics in the classroom, we provide a qualitative explanation of the terms of the Lagrangian and discuss their interpretation based on associated Feynman diagrams.

LECTURES ON PHYSICS, BIOPHYSICS, AND CHEMISTRY FOR HIGH SCHOOL SCIENCE TEACHERS GIVEN AT THE ERNEST O. LAWRENCE RADIATION LABORATORY, BERKELEY, CALIFORNIA, JUNE-AUGUST 1959

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calhoon, E.C.; Starring, P.W. eds.

1959-08-01

Lectures given at the Ernest 0. Lawrence Radiation Laboratory on physics, biophysics, and chemistry for high school science teachers are presented. Topics covered include a mathematics review, atomic physics, nuclear physics, solid-state physics, elementary particles, antiparticies, design of experiments, high-energy particle accelerators, survey of particle detectors, emulsion as a particle detector, counters used in high-energy physics, bubble chambers, computer programming, chromatography, the transuranium elements, health physics, photosynthesis, the chemistry and physics of virus, the biology of virus, lipoproteins and heart disease, origin and evolution of the solar system, the role of space satellites in gathering astronomical data, and radiation andmore » life in space. (M.C.G.)« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calixto, M., E-mail: calixto@ugr.es; Pérez-Romero, E.

We revise the unireps. of U(2, 2) describing conformal particles with continuous mass spectrum from a many-body perspective, which shows massive conformal particles as compounds of two correlated massless particles. The statistics of the compound (boson/fermion) depends on the helicity h of the massless components (integer/half-integer). Coherent states (CS) of particle-hole pairs (“excitons”) are also explicitly constructed as the exponential action of exciton (non-canonical) creation operators on the ground state of unpaired particles. These CS are labeled by points Z (2×2 complex matrices) on the Cartan-Bergman domain D₄=U(2,2)/U(2)², and constitute a generalized (matrix) version of Perelomov U(1, 1) coherent statesmore » labeled by points z on the unit disk D₁=U(1,1)/U(1)². First, we follow a geometric approach to the construction of CS, orthonormal basis, U(2, 2) generators and their matrix elements and symbols in the reproducing kernel Hilbert space H{sub λ}(D₄) of analytic square-integrable holomorphic functions on D₄, which carries a unitary irreducible representation of U(2, 2) with index λϵN (the conformal or scale dimension). Then we introduce a many-body representation of the previous construction through an oscillator realization of the U(2, 2) Lie algebra generators in terms of eight boson operators with constraints. This particle picture allows us for a physical interpretation of our abstract mathematical construction in the many-body jargon. In particular, the index λ is related to the number 2(λ – 2) of unpaired quanta and to the helicity h = (λ – 2)/2 of each massless particle forming the massive compound.« less

Integrating Condensed Matter Physics into a Liberal Arts Physics Curriculum

NASA Astrophysics Data System (ADS)

Collett, Jeffrey

2008-03-01

The emergence of nanoscale science into the popular consciousness presents an opportunity to attract and retain future condensed matter scientists. We inject nanoscale physics into recruiting activities and into the introductory and the core portions of the curriculum. Laboratory involvement and research opportunity play important roles in maintaining student engagement. We use inexpensive scanning tunneling (STM) and atomic force (AFM) microscopes to introduce students to nanoscale structure early in their college careers. Although the physics of tip-surface interactions is sophisticated, the resulting images can be interpreted intuitively. We use the STM in introductory modern physics to explore quantum tunneling and the properties of electrons at surfaces. An interdisciplinary course in nanoscience and nanotechnology course team-taught with chemists looks at nanoscale phenomena in physics, chemistry, and biology. Core quantum and statistical physics courses look at effects of quantum mechanics and quantum statistics in degenerate systems. An upper level solid-state physics course takes up traditional condensed matter topics from a structural perspective by beginning with a study of both elastic and inelastic scattering of x-rays from crystalline solids and liquid crystals. Students encounter reciprocal space concepts through the analysis of laboratory scattering data and by the development of the scattering theory. The course then examines the importance of scattering processes in band structure and in electrical and thermal conduction. A segment of the course is devoted to surface physics and nanostructures where we explore the effects of restricting particles to two-dimensional surfaces, one-dimensional wires, and zero-dimensional quantum dots.

Particle and nuclear physics instrumentation and its broad connections

DOE PAGES

Demarteau, Marcel; Lipton, Ron; Nicholson, Howard; ...

2016-12-20

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector researchmore » and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. Finally, this symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.« less

Particle and nuclear physics instrumentation and its broad connections

NASA Astrophysics Data System (ADS)

Demarteau, M.; Lipton, R.; Nicholson, H.; Shipsey, I.

2016-10-01

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector research and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. This symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.

Particle and nuclear physics instrumentation and its broad connections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demarteau, Marcel; Lipton, Ron; Nicholson, Howard

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector researchmore » and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. Finally, this symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.« less

Tunable particles alter macrophage uptake based on combinatorial effects of physical properties

PubMed Central

Garapaty, Anusha

2017-01-01

Abstract The ability to tune phagocytosis of particle‐based therapeutics by macrophages can enhance their delivery to macrophages or reduce their phagocytic susceptibility for delivery to non‐phagocytic cells. Since phagocytosis is affected by the physical and chemical properties of particles, it is crucial to identify any interplay between physical properties of particles in altering phagocytic interactions. The combinatorial effect of physical properties size, shape and stiffness was investigated on Fc receptor mediated macrophage interactions by fabrication of layer‐by‐layer tunable particles of constant surface chemistry. Our results highlight how changing particle stiffness affects phagocytic interaction intricately when combined with varying size or shape. Increase in size plays a dominant role over reduction in stiffness in reducing internalization by macrophages for spherical particles. Internalization of rod‐shaped, but not spherical particles, was highly dependent on stiffness. These particles demonstrate the interplay between size, shape and stiffness in interactions of Fc‐functionalized particles with macrophages during phagocytosis. PMID:29313025

Analytical approaches for the characterization and quantification of nanoparticles in food and beverages.

PubMed

Mattarozzi, Monica; Suman, Michele; Cascio, Claudia; Calestani, Davide; Weigel, Stefan; Undas, Anna; Peters, Ruud

2017-01-01

Estimating consumer exposure to nanomaterials (NMs) in food products and predicting their toxicological properties are necessary steps in the assessment of the risks of this technology. To this end, analytical methods have to be available to detect, characterize and quantify NMs in food and materials related to food, e.g. food packaging and biological samples following metabolization of food. The challenge for the analytical sciences is that the characterization of NMs requires chemical as well as physical information. This article offers a comprehensive analysis of methods available for the detection and characterization of NMs in food and related products. Special attention was paid to the crucial role of sample preparation methods since these have been partially neglected in the scientific literature so far. The currently available instrumental methods are grouped as fractionation, counting and ensemble methods, and their advantages and limitations are discussed. We conclude that much progress has been made over the last 5 years but that many challenges still exist. Future perspectives and priority research needs are pointed out. Graphical Abstract Two possible analytical strategies for the sizing and quantification of Nanoparticles: Asymmetric Flow Field-Flow Fractionation with multiple detectors (allows the determination of true size and mass-based particle size distribution); Single Particle Inductively Coupled Plasma Mass Spectrometry (allows the determination of a spherical equivalent diameter of the particle and a number-based particle size distribution).

Particles, particles everywhere: What is in the air we breathe?

USDA-ARS?s Scientific Manuscript database

Particulate matter (PM) air pollution consists of extremely small particles, some so small that they can directly enter the bloodstream through the lungs. PM is of prime concern from both health and environmental perspectives. Current research is focused on understanding how PM forms in the atmosphe...

Embodiment: A New Perspective for Evaluating Physicality in Learning

ERIC Educational Resources Information Center

Han, Insook

2013-01-01

The purpose of this study is to provide a new perspective for evaluating physicality in learning with a preliminary experimental study based on embodied cognition. While there are studies showing no superiority of physical manipulation over virtual manipulation, there are also studies that seem to advocate adding more physicality in simulations…

Alienation in Physical Education from the Perspectives of Children

ERIC Educational Resources Information Center

Spencer-Cavaliere, Nancy; Rintoul, Mary Ann

2012-01-01

The purpose of this exploratory study was to examine the phenomenon of alienation in physical education from the perspectives of children. Of particular interest were children's perspectives about the three constructs of alienation: (a) powerlessness, (b) meaninglessness, and (c) social isolation, as defined by Carlson (1995). A case study…

A Gender Perspective on Educational Facilities

ERIC Educational Resources Information Center

Lang, Sara

2010-01-01

This article explores how to adopt a gender perspective in the analysis of educational facilities. It argues that social relations are influenced by the physical environment, and that social and physical aspects are often interlinked. Although difficult to measure, including a gender perspective in international research and other projects on…

Teaching Elementary Particle Physics: Part I

ERIC Educational Resources Information Center

Hobson, Art

2011-01-01

I'll outline suggestions for teaching elementary particle physics, often called "high energy physics," in high school or introductory college courses for non-scientists or scientists. Some presentations of this topic simply list the various particles along with their properties, with little overarching structure. Such a laundry list approach is a…

The Ultimate Structure of Matter: The High Energy Physics Program from the 1950s through the 1980s

DOE R&D Accomplishments Database

1990-02-01

This discusses the following topics in High Energy Physics: The Particle Zoo; The Strong and the Weak; The Particle Explosion; Deep Inside the Nucleon; The Search for Unity; Physics in Collision; The Standard Model; Particles and the Cosmos; and Practical Benefits.

Computer Simulations for Lab Experiences in Secondary Physics

ERIC Educational Resources Information Center

Murphy, David Shannon

2012-01-01

Physical science instruction often involves modeling natural systems, such as electricity that possess particles which are invisible to the unaided eye. The effect of these particles' motion is observable, but the particles are not directly observable to humans. Simulations have been developed in physics, chemistry and biology that, under certain…

[Meta-analyses of quarks, baryons and mesons--a "Cochrane Collaboration" in particle physics].

PubMed

Sauerland, Stefan; Sauerland, Thankmar; Antes, Gerd; Barnett, R Michael

2002-02-01

Within the last 20 years meta-analysis has become an important research technique in medicine for integrating the results of independent studies. Meta-analytical techniques, however, are much older. In particle physics for 50 years now the properties of huge numbers of particles have been assessed in meta-analyses. The Cochrane Collaboration's counterpart in physics is the Particle Data Group. This article compares methodological and organisational aspects of meta-analyses in medicine and physics. Several interesting parallels exist, especially with regard to methodology.

ALICE Masterclass on strangeness

NASA Astrophysics Data System (ADS)

Foka, Panagiota; Janik, Małgorzata

2014-04-01

An educational activity, the International Particle Physics Masterclasses, was developed by the International Particle Physics Outreach Group with the aim to bring the excitement of cutting-edge particle-physics research into the classroom. Thousands of pupils, every year since 2005, in many countries all over the world, are hosted in research centers or universities close to their schools and become "scientists for a day" as they are introduced to the mysteries of particle physics. The program of a typical day includes lectures that give insight to topics and methods of fundamental research followed by a "hands-on" session where the high-school students perform themselves measurements on real data from particle-physics experiments. The last three years data from the ALICE experiment at LHC were used. The performed measurement "strangeness enhancement" and the employed methodology are presented.

EDITORIAL: Focus on Dark Matter and Particle Physics

NASA Astrophysics Data System (ADS)

Aprile, Elena; Profumo, Stefano

2009-10-01

The quest for the nature of dark matter has reached a historical point in time, with several different and complementary experiments on the verge of conclusively exploring large portions of the parameter space of the most theoretically compelling particle dark matter models. This focus issue on dark matter and particle physics brings together a broad selection of invited articles from the leading experimental and theoretical groups in the field. The leitmotif of the collection is the need for a multi-faceted search strategy that includes complementary experimental and theoretical techniques with the common goal of a sound understanding of the fundamental particle physical nature of dark matter. These include theoretical modelling, high-energy colliders and direct and indirect searches. We are confident that the works collected here present the state of the art of this rapidly changing field and will be of interest to both experts in the topic of dark matter as well as to those new to this exciting field. Focus on Dark Matter and Particle Physics Contents DARK MATTER AND ASTROPHYSICS Scintillator-based detectors for dark matter searches I S K Kim, H J Kim and Y D Kim Cosmology: small-scale issues Joel R Primack Big Bang nucleosynthesis and particle dark matter Karsten Jedamzik and Maxim Pospelov Particle models and the small-scale structure of dark matter Torsten Bringmann DARK MATTER AND COLLIDERS Dark matter in the MSSM R C Cotta, J S Gainer, J L Hewett and T G Rizzo The role of an e+e- linear collider in the study of cosmic dark matter M Battaglia Collider, direct and indirect detection of supersymmetric dark matter Howard Baer, Eun-Kyung Park and Xerxes Tata INDIRECT PARTICLE DARK MATTER SEARCHES:EXPERIMENTS PAMELA and indirect dark matter searches M Boezio et al An indirect search for dark matter using antideuterons: the GAPS experiment C J Hailey Perspectives for indirect dark matter search with AMS-2 using cosmic-ray electrons and positrons B Beischer, P von Doetinchem, H Gast, T Kirn and S Schael Axion searches with helioscopes and astrophysical signatures for axion(-like) particles K Zioutas, M Tsagri, Y Semertzidis, T Papaevangelou, T Dafni and V Anastassopoulos The indirect search for dark matter with IceCube Francis Halzen and Dan Hooper DIRECT DARK MATTER SEARCHES:EXPERIMENTS Gaseous dark matter detectors G Sciolla and C J Martoff Search for dark matter with CRESST Rafael F Lang and Wolfgang Seidel DIRECT AND INDIRECT PARTICLE DARK MATTER SEARCHES:THEORY Dark matter annihilation around intermediate mass black holes: an update Gianfranco Bertone, Mattia Fornasa, Marco Taoso and Andrew R Zentner Update on the direct detection of dark matter in MSSM models with non-universal Higgs masses John Ellis, Keith A Olive and Pearl Sandick Dark stars: a new study of the first stars in the Universe Katherine Freese, Peter Bodenheimer, Paolo Gondolo and Douglas Spolyar Determining the mass of dark matter particles with direct detection experiments Chung-Lin Shan The detection of subsolar mass dark matter halos Savvas M Koushiappas Neutrino coherent scattering rates at direct dark matter detectors Louis E Strigari Gamma rays from dark matter annihilation in the central region of the Galaxy Pasquale Dario Serpico and Dan Hooper DARK MATTER MODELS The dark matter interpretation of the 511 keV line Céline Boehm Axions as dark matter particles Leanne D Duffy and Karl van Bibber Sterile neutrinos Alexander Kusenko Dark matter candidates Lars Bergström Minimal dark matter: model and results Marco Cirelli and Alessandro Strumia Shedding light on the dark sector with direct WIMP production Partha Konar, Kyoungchul Kong, Konstantin T Matchev and Maxim Perelstein Axinos as dark matter particles Laura Covi and Jihn E Kim

Physical Education and Health: Global Perspectives and Best Practice

ERIC Educational Resources Information Center

Chin, Ming-Kai, Ed.; Edginton, Christopher R.

2014-01-01

"Physical Education and Health: Global Perspectives and Best Practice" draws together global scholars, researchers, and practitioners to provide a review and analysis of new directions in physical education and health worldwide. The book provides descriptive information from 40 countries regarding contemporary practices, models, and…

Three-Dimensional Visualization of Particle Tracks.

ERIC Educational Resources Information Center

Julian, Glenn M.

1993-01-01

Suggests ways to bring home to the introductory physics student some of the excitement of recent discoveries in particle physics. Describes particle detectors and encourages the use of the Standard Model along with real images of particle tracks to determine three-dimensional views of tracks. (MVL)

Plato's TIMAIOσ (TIMAEUS) and Modern Particle Physics

NASA Astrophysics Data System (ADS)

Machleidt, Ruprecht

2005-04-01

It is generally known that the question, ``What are the smallest particles (elementary particles) that all matter is made from?'', was posed already in the antiquity. The Greek natural philosophers Leucippus and Democritus were the first to suggest that all matter was made from atoms. Therefore, most people perceive them as the ancient fathers of elementary particle physics. It will be the purpose of my contribution to point out that this perception is wrong. Modern particle physics is not just a primitive atomism. More important than the materialistic particles are the underlying symmetries (e. g., SU(3) and SU(6)). A similar idea was first advanced by Plato in his dialog TIMAIOσ (Latin translation: TIMAEUS): Geometric symmetries generate the materialistic particles from a few even more elementary items. Plato's vision is amazingly close to the ideas of modern particle physics. This fact, which is unfortunately little known, has been pointed out repeatedly by Heisenberg (see, e. g., Werner Heisenberg, Across the Frontiers, Harper & Row, New York, 1974).

Fermilab | Mu2e

Science.gov Websites

Interactions.org Particle Physics News Image Bank Fermilab in the News Quantum Diaries Mu2e: muon-to-electron works The Mu2e detector is a particle physics detector embedded in a series of superconducting magnets advance research at the Intensity Frontier. The U.S. Particle Physics Project Prioritization Panel, P5

History of Particle Physics

Science.gov Websites

back to history page Back Particle Physics Timeline For over two thousand years people have thought the Standard Model. We invite you to explore this history of particle physics with a focus on the : Quantum Theory 1964 - Present: The Modern View (the Standard Model) back to history page Back Sections of

Quarked!--Adventures in Particle Physics Education

ERIC Educational Resources Information Center

MacDonald, Teresa; Bean, Alice

2009-01-01

Particle physics is a subject that can send shivers down the spines of students and educators alike--with visions of long mathematical equations and inscrutable ideas. This perception, along with a full curriculum, often leaves this topic the road less traveled until the latter years of school. Particle physics, including quarks, is typically not…

Let's Have a Coffee with the Standard Model of Particle Physics!

ERIC Educational Resources Information Center

Woithe, Julia; Wiener, Gerfried J.; Van der Veken, Frederik F.

2017-01-01

The Standard Model of particle physics is one of the most successful theories in physics and describes the fundamental interactions between elementary particles. It is encoded in a compact description, the so-called "Lagrangian," which even fits on t-shirts and coffee mugs. This mathematical formulation, however, is complex and only…

Teaching Perspectives of Chinese Teachers: Compatibility with the Goals of the Physical Education Curriculum

ERIC Educational Resources Information Center

Wang, Lijuan; Ha, Amy Sau-ching; Wen, Xu

2014-01-01

This research primarily aimed to examine the compatibility of teaching perspectives of teachers with the Physical Education (PE) curriculum in China. The Teaching Perspective Inventory (Pratt, 1998) was used to collect data from 272 PE teachers. Descriptive statistics, MANOVAs, and correlational procedures were used for quantitative data analysis.…

Time perspective, personality and smoking, body mass, and physical activity: an empirical study.

PubMed

Adams, Jean; Nettle, Daniel

2009-02-01

Time perspective describes how individuals conceptualize and value future events, and may be related to health behaviours. Research to date has focused on addictive behaviours, used a variety of different measures of time perspective, and not explored the role of personality. This work aimed to: explore the relationships between: five previously used measures of time perspective; time perspective and the broad domains of the five-factor model of personality; and time perspective and smoking, body mass, and physical activity after controlling for socio-demographics and personality. Cross-sectional self-report data were collected using a web based survey. Participants (N=423) were recruited via local community internet message boards in US urban areas. The survey collected information on: delay discount rate, the Consideration of Future Consequences Scale (CFCS), the future scale of the Zimbardo Time Perspective Inventory (ZTPI), subjective probability of living to age 75, and time period for financial planning, the five-factor personality inventory, smoking, body mass index (BMI), and physical activity. After controlling for socio-demographics, most markers of time perspective were significantly correlated with each other, but the strength of correlations was rarely strong. Conscientiousness, Neuroticism, Agreeableness, and Openness were associated with some markers of time perspective. After controlling for socio-demographic and personality domains, only CFCS score was associated with smoking status and BMI. There is some overlap between previously used markers of time perspective and the five-factor personality domains but this is neither strong nor consistent. Smoking and BMI, but not physical activity, are associated with CFCS, but not other measures of time perspective.

On some physical and dynamical properties of microplastic particles in marine environment.

PubMed

Chubarenko, I; Bagaev, A; Zobkov, M; Esiukova, E

2016-07-15

Simplified physical models and geometrical considerations reveal general physical and dynamical properties of microplastic particles (0.5-5mm) of different density, shape and size in marine environment. Windage of extremely light foamed particles, surface area and fouling rate of slightly positively buoyant microplastic spheres, films and fibres and settling velocities of negatively buoyant particles are analysed. For the Baltic Sea dimensions and under the considered idealised external conditions, (i) only one day is required for a foamed polystyrene particle to cross the sea (ca. 250km); (ii) polyethylene fibres should spend about 6-8months in the euphotic zone before sinking due to bio-fouling, whilst spherical particles can be retained on the surface up to 10-15years; (iii) for heavy microplastic particles, the time of settling through the water column in the central Gotland basin (ca. 250m) is less than 18h. Proper physical setting of the problem of microplastics transport and developing of physically-based parameterisations are seen as applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phase structuring in metal alloys: Ultrasound-assisted top-down approach to engineering of nanostructured catalytic materials.

PubMed

Cherepanov, Pavel V; Andreeva, Daria V

2017-03-01

High intensity ultrasound (HIUS) is a novel and efficient tool for top-down nanostructuring of multi-phase metal systems. Ultrasound-assisted structuring of the phase in metal alloys relies on two main mechanisms including interfacial red/ox reactions and temperature driven solid state phase transformations which affect surface composition and morphology of metals. Physical and chemical properties of sonication medium strongly affects the structuring pathways as well as morphology and composition of catalysts. HIUS can serve as a simple, fast, and effective approach for the tuning of structure and surface properties of metal particles, opening the new perspectives in design of robust and efficient catalysts. Copyright © 2016 Elsevier B.V. All rights reserved.

Cosmology: from Pomeranchuk to the present day

NASA Astrophysics Data System (ADS)

Dolgov, A. D.

2014-02-01

A review of half a century of cosmology is presented for an intended audience of elementary particle physicists. The review is based on a half-hour seminar talk (at the Institute of Theoretical and Experimental Physics, ITEP) and is therefore brief and superficial. The introductory historical section is mostly devoted to the fundamental work done in, but not always known outside, Russia (USSR). Foundational works and astronomical observations instrumental in shaping the field are discussed, as are inflation, baryosynthesis, dark matter and dark energy, vacuum energy, large-scale gravity modifications, and microwave background angular fluctuations. The presentation is admittedly not entirely objective but rather is given from the Russian (ITEP) perspective and is influenced by the author's personal views and biases.

The Compton generator revisited

NASA Astrophysics Data System (ADS)

Siboni, S.

2014-09-01

The Compton generator, introduced in 1913 by the US physicist A H Compton as a relatively simple device to detect the Earth's rotation with respect to the distant stars, is analyzed and discussed in a general perspective. The paper introduces a generalized definition of the generator, emphasizing the special features of the original apparatus, and provides a suggestive interpretation of the way the device works. To this end, an intriguing electromagnetic analogy is developed, which turns out to be particularly useful in simplifying the calculations. Besides the more extensive description of the Compton generator in itself, the combined use of concepts and methods coming from different fields of physics, such as particle dynamics in moving references frames, continuum mechanics and electromagnetism, may be of interest to both teachers and graduate students.

Proceedings of the 24. SLAC summer institute on particle physics: The strong interaction, from hadrons to partons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, J.; DePorcel, L.; Dixon, L.

1997-06-01

This conference explored the role of the strong interaction in the physics of hadrons and partons. The Institute attracted 239 physicists from 16 countries to hear lectures on the underlying theory of Quantum Chromodynamics, modern theoretical calculational techniques, and experimental investigation of the strong interaction as it appears in various phenomena. Different regimes in which one can calculate reliably in QCD were addressed in series of lectures on perturbation theory, lattice gauge theories, and heavy quark expansions. Studies of QCD in hadron-hadron collisions, electron-positron annihilation, and electron-proton collisions all give differing perspectives on the strong interaction--from low-x to high-Q{sup 2}.more » Experimental understanding of the production and decay of heavy quarks as well as the lighter meson states has continued to evolve over the past years, and these topics were also covered at the School. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.« less

The Physical Microbe; An introduction to noise, control, and communication in the prokaryotic cell

NASA Astrophysics Data System (ADS)

Hagen, Stephen J.

2017-10-01

Physical biology is a fusion of biology and physics. This book narrows down the scope of physical biology by focusing on the microbial cell; exploring the physical phenomena of noise, feedback, and variability that arise in the cellular information-processing circuits used by bacteria. It looks at the microbe from a physics perspective, asking how the cell optimizes its function to live within the constraints of physics. It introduces a physical and information-based (as opposed to microbiological) perspective on communication and signalling between microbes.

Observation of ultra high energy cosmic rays from space: Status and perspectives

NASA Astrophysics Data System (ADS)

Casolino, M.; Klimov, P.; Piotrowski, L.

2017-12-01

The study of ultra high energy cosmic rays (UHECRs) offers unique possibilities to probe the energies currently inaccessible by man-made accelerators. Recent years have shed light on several characteristics of these particles, but—due to their extremely low flux—their origin, nature, and acceleration mechanisms are still unclear. Space-based observations have the potential for an increase in statistics, up to several orders of magnitude, and would be able to cover the whole sky, allowing for a direct comparison of spectra and direction of arrival. A detector with the exposure of a few times that of the Pierre Auger Observatory would be able to clarify the observed differences between the northern and southern skies, confirm the existence of TA hot spot, and measure multipolar anisotropies with high precision. A number of novel technologies—from optics to sensors, front-end and read-out electronics—have been developed over the years to achieve this goal. In this paper we describe the progress and results obtained so far and discuss the perspectives of UHECR physics observation from space.

Physical Principles of the Method for Determination of Geometrical Characteristics and Particle Recognition in Digital Holography

NASA Astrophysics Data System (ADS)

Dyomin, V. V.; Polovtsev, I. G.; Davydova, A. Yu.

2018-03-01

The physical principles of a method for determination of geometrical characteristics of particles and particle recognition based on the concepts of digital holography, followed by processing of the particle images reconstructed from the digital hologram, using the morphological parameter are reported. An example of application of this method for fast plankton particle recognition is given.

Inclusion Practices in Elementary Physical Education: A Social-Cognitive Perspective

ERIC Educational Resources Information Center

An, Jihoun; Meaney, Karen S.

2015-01-01

This study explored inclusion practices in general physical education (GPE) from the experiences and perspectives of elementary physical education teachers. The stories of four teachers (two females, two males) between 27 and 57 years of age were gathered using the phenomenological methods of semi-structured interviews, photographs, school…

Ecology and Physics of Bacterial Chemotaxis in the Ocean

PubMed Central

Seymour, Justin R.

2012-01-01

Summary: Intuitively, it may seem that from the perspective of an individual bacterium the ocean is a vast, dilute, and largely homogeneous environment. Microbial oceanographers have typically considered the ocean from this point of view. In reality, marine bacteria inhabit a chemical seascape that is highly heterogeneous down to the microscale, owing to ubiquitous nutrient patches, plumes, and gradients. Exudation and excretion of dissolved matter by larger organisms, lysis events, particles, animal surfaces, and fluxes from the sediment-water interface all contribute to create strong and pervasive heterogeneity, where chemotaxis may provide a significant fitness advantage to bacteria. The dynamic nature of the ocean imposes strong selective pressures on bacterial foraging strategies, and many marine bacteria indeed display adaptations that characterize their chemotactic motility as “high performance” compared to that of enteric model organisms. Fast swimming speeds, strongly directional responses, and effective turning and steering strategies ensure that marine bacteria can successfully use chemotaxis to very rapidly respond to chemical gradients in the ocean. These fast responses are advantageous in a broad range of ecological processes, including attaching to particles, exploiting particle plumes, retaining position close to phytoplankton cells, colonizing host animals, and hovering at a preferred height above the sediment-water interface. At larger scales, these responses can impact ocean biogeochemistry by increasing the rates of chemical transformation, influencing the flux of sinking material, and potentially altering the balance of biomass incorporation versus respiration. This review highlights the physical and ecological processes underpinning bacterial motility and chemotaxis in the ocean, describes the current state of knowledge of chemotaxis in marine bacteria, and summarizes our understanding of how these microscale dynamics scale up to affect ecosystem-scale processes in the sea. PMID:23204367

Ecology and physics of bacterial chemotaxis in the ocean.

PubMed

Stocker, Roman; Seymour, Justin R

2012-12-01

Intuitively, it may seem that from the perspective of an individual bacterium the ocean is a vast, dilute, and largely homogeneous environment. Microbial oceanographers have typically considered the ocean from this point of view. In reality, marine bacteria inhabit a chemical seascape that is highly heterogeneous down to the microscale, owing to ubiquitous nutrient patches, plumes, and gradients. Exudation and excretion of dissolved matter by larger organisms, lysis events, particles, animal surfaces, and fluxes from the sediment-water interface all contribute to create strong and pervasive heterogeneity, where chemotaxis may provide a significant fitness advantage to bacteria. The dynamic nature of the ocean imposes strong selective pressures on bacterial foraging strategies, and many marine bacteria indeed display adaptations that characterize their chemotactic motility as "high performance" compared to that of enteric model organisms. Fast swimming speeds, strongly directional responses, and effective turning and steering strategies ensure that marine bacteria can successfully use chemotaxis to very rapidly respond to chemical gradients in the ocean. These fast responses are advantageous in a broad range of ecological processes, including attaching to particles, exploiting particle plumes, retaining position close to phytoplankton cells, colonizing host animals, and hovering at a preferred height above the sediment-water interface. At larger scales, these responses can impact ocean biogeochemistry by increasing the rates of chemical transformation, influencing the flux of sinking material, and potentially altering the balance of biomass incorporation versus respiration. This review highlights the physical and ecological processes underpinning bacterial motility and chemotaxis in the ocean, describes the current state of knowledge of chemotaxis in marine bacteria, and summarizes our understanding of how these microscale dynamics scale up to affect ecosystem-scale processes in the sea.

All-loop Mondrian diagrammatics and 4-particle amplituhedron

NASA Astrophysics Data System (ADS)

An, Yang; Li, Yi; Li, Zhinan; Rao, Junjie

2018-06-01

Based on 1712.09990 which handles the 4-particle amplituhedron at 3-loop, we have found an extremely simple pattern, yet far more non-trivial than one might naturally expect: the all-loop Mondrian diagrammatics. By further simplifying and rephrasing the key relation of positivity in the amplituhedron setting, remarkably, we find a completeness relation unifying all diagrams of the Mondrian types for the 4-particle integrand of planar N = 4 SYM to all loop orders, each of which can be mapped to a simple product following a few plain rules designed for this relation. The explicit examples we investigate span from 3-loop to 7-loop order, and based on them, we classify the basic patterns of Mondrian diagrams into four types: the ladder, cross, brick-wall and spiral patterns. Interestingly, for some special combinations of ordered subspaces (a concept defined in the previous work), we find failed exceptions of the completeness relation which are called "anomalies", nevertheless, they substantially give hints on the all-loop recursive proof of this relation. These investigations are closely related to the combinatoric knowledge of separable permutations and Schröder numbers, and go even further from a diagrammatic perspective. For physical relevance, we need to further consider dual conformal invariance for two basic diagrammatic patterns to correct the numerator for a local integrand involving one or both of such patterns, while the denominator encoding its pole structure and also the sign factor, are already fixed by rules of the completeness relation. With this extra treatment to ensure the integrals are dual conformally invariant, each Mondrian diagram can be exactly translated to its corresponding physical loop integrand after being summed over all ordered subspaces that admit it.

News

NASA Astrophysics Data System (ADS)

2002-03-01

UK Awards: Teacher of Physics Awards Institute Matters: Institute of Physics Education Conference UK Awards: Top SHAP students win prizes Competition: International creative essay competition UK Awards: Kelvin Medal Particle Physics Resources: New poster from PPARC Australia: Physics Students's Day at Adventure World UK Awards: Bragg Medal winners in a FLAP ASE Annual Meeting: Particle Physics at ASE 2002 UK Grants: PPARC Awards AAPT Winter Meeting: Physics First - but do you need maths? UK In-Service Training: The Particle Physics Institutes for A-level teachers Physics on Stage 2: Not too entertaining this time, please! Scotland: A reasoned approach wins reasonable funding Institute Matters: New education manager Germany: Physics gets real: curriculum change for better teaching Research Frontiers: Let there be light - if you hang on a minute

The International Committee for Future Accelerators (ICFA): 1976 to the present

DOE PAGES

Rubinstein, Roy

2016-12-14

The International Committee for Future Accelerators (ICFA) has been in existence now for four decades. It plays an important role in allowing discussions by the world particle physics community on the status and future of very large particle accelerators and the particle physics and related fields associated with them. Here, this paper gives some indication of what ICFA is and does, and also describes its involvement in some of the more important developments in the particle physics field since its founding.

Physical Attractiveness Research. Toward a Developmental Social Psychology of Beauty

ERIC Educational Resources Information Center

Adams, G. R.

1977-01-01

This paper reviews research on physical attractiveness from a dialectical-interactional perspective and attempts to examine the relationship between outer appearance and inner psychological characteristics from a developmental perspective. (BD)

The roots of physics students' motivations: Fear and integrity

NASA Astrophysics Data System (ADS)

Van Dusen, Ben

Too often, physics students are beset by feelings of failure and isolation rather than experiencing the creative joys of discovery that physics has to offer. This dissertation research was founded on the desire of a teacher to make physics class exciting and motivating to his students. This work explores how various aspects of learning environments interact with student motivation. This work uses qualitative and quantitative methods to explore how students are motivated to engage in physics and how they feel about themselves while engaging in physics. The collection of four studies in this dissertation culminates in a sociocultural perspective on motivation and identity. This perspective uses two extremes of how students experience physics as a lens for understanding motivation: fear and self-preservation versus integrity and self-expression. Rather than viewing motivation as a property of the student, or viewing students as inherently interested or disinterested in physics, the theoretical perspective on motivation and identity helps examine features of the learning environments that determine how students' experience themselves through physics class. This perspective highlights the importance of feeling a sense of belonging in the context of physics and the power that teachers have in shaping students' motivation through the construction of their classroom learning environments. Findings demonstrate how different ways that students experience themselves in physics class impact their performance and interest in physics. This dissertation concludes with a set of design principles that can foster integration and integrity among students in physics learning environments.

Single Aerosol Particle Studies Using Optical Trapping Raman And Cavity Ringdown Spectroscopy

NASA Astrophysics Data System (ADS)

Gong, Z.; Wang, C.; Pan, Y. L.; Videen, G.

2017-12-01

Due to the physical and chemical complexity of aerosol particles and the interdisciplinary nature of aerosol science that involves physics, chemistry, and biology, our knowledge of aerosol particles is rather incomplete; our current understanding of aerosol particles is limited by averaged (over size, composition, shape, and orientation) and/or ensemble (over time, size, and multi-particles) measurements. Physically, single aerosol particles are the fundamental units of any large aerosol ensembles. Chemically, single aerosol particles carry individual chemical components (properties and constituents) in particle ensemble processes. Therefore, the study of single aerosol particles can bridge the gap between aerosol ensembles and bulk/surface properties and provide a hierarchical progression from a simple benchmark single-component system to a mixed-phase multicomponent system. A single aerosol particle can be an effective reactor to study heterogeneous surface chemistry in multiple phases. Latest technological advances provide exciting new opportunities to study single aerosol particles and to further develop single aerosol particle instrumentation. We present updates on our recent studies of single aerosol particles optically trapped in air using the optical-trapping Raman and cavity ringdown spectroscopy.

Georges Charpak, Particle Detectors, and Multiwire Chambers

Science.gov Websites

particle detectors used throughout experimental particle physics. In 1968, he invented and developed the the 2005 International Year of Physics (video) Top Some links on this page may take you to non-federal

Probing the frontiers of particle physics with tabletop-scale experiments.

PubMed

DeMille, David; Doyle, John M; Sushkov, Alexander O

2017-09-08

The field of particle physics is in a peculiar state. The standard model of particle theory successfully describes every fundamental particle and force observed in laboratories, yet fails to explain properties of the universe such as the existence of dark matter, the amount of dark energy, and the preponderance of matter over antimatter. Huge experiments, of increasing scale and cost, continue to search for new particles and forces that might explain these phenomena. However, these frontiers also are explored in certain smaller, laboratory-scale "tabletop" experiments. This approach uses precision measurement techniques and devices from atomic, quantum, and condensed-matter physics to detect tiny signals due to new particles or forces. Discoveries in fundamental physics may well come first from small-scale experiments of this type. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

The Birth of Elementary-Particle Physics.

ERIC Educational Resources Information Center

Brown, Laurie M.; Hoddeson, Lillian

1982-01-01

Traces the origin and development of particle physics, concentrating on the roles of cosmic rays and theory. Includes charts highlighting significant events in the development of cosmic-ray physics and quantum field theory. (SK)

Can Grade-6 Students Understand Quarks? Probing Acceptance of the Subatomic Structure of Matter with 12-Year-Olds

ERIC Educational Resources Information Center

Wiener, Gerfried J.; Schmeling, Sascha M.; Hopf, Martin

2015-01-01

This study introduces a teaching concept based on the Standard Model of particle physics. It comprises two consecutive chapters--elementary particles and fundamental interactions. The rationale of this concept is that the fundamental principles of particle physics can run as the golden thread through the whole physics curriculum. The design…

The solid state physics programme at ISOLDE: recent developments and perspectives

NASA Astrophysics Data System (ADS)

Johnston, Karl; Schell, Juliana; Correia, J. G.; Deicher, M.; Gunnlaugsson, H. P.; Fenta, A. S.; David-Bosne, E.; Costa, A. R. G.; Lupascu, Doru C.

2017-10-01

Solid state physics (SSP) research at ISOLDE has been running since the mid-1970s and accounts for about 10%-15% of the overall physics programme. ISOLDE is the world flagship for the on-line production of exotic radioactive isotopes, with high yields, high elemental selectivity and isotopic purity. Consequently, it hosts a panoply of state-of-the-art nuclear techniques which apply nuclear methods to research on life sciences, material science and bio-chemical physics. The ease of detecting radioactivity—<1 ppm concentrations—is one of the features which distinguishes the use of radioisotopes for materials science research. The manner in which nuclear momenta of excited nuclear states interact with their local electronic and magnetic environment, or how charged emitted particles interact with the crystalline lattices allow the determination of the location, its action and the role of the selected impurity element at the nanoscopic state. ISOLDE offers an unrivalled range of available radioactive elements and this is attracting an increasing user community in the field of nuclear SSP research and brings together a community of materials scientists and specialists in nuclear solid state techniques. This article describes the current status of this programme along with recent illustrative results, predicting a bright future for these unique research methods and collaborations.

Time-dependent radiation dose estimations during interplanetary space flights

NASA Astrophysics Data System (ADS)

Dobynde, M. I.; Shprits, Y.; Drozdov, A.

2015-12-01

Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow of secondary induced particles and minimizing most harmful particle types flows.

Measurement of Meteor Impact Experiments Using Three-Component Particle Image Velocimetry

NASA Technical Reports Server (NTRS)

Heineck, James T.; Schultz, Peter H.

2002-01-01

The study of hypervelocity impacts has been aggressively pursued for more than 30 years at Ames as a way to simulate meteoritic impacts. Development of experimental methods coupled with new perspectives over this time has greatly improved the understanding of the basic physics and phenomenology of the impact process. These fundamental discoveries have led to novel methods for identifying impact craters and features in craters on both Earth and other planetary bodies. Work done at the Ames Vertical Gun Range led to the description of the mechanics of the Chicxualub crater (a.k.a. K-T crater) on the Yucatan Peninsula, widely considered to be the smoking gun impact that brought an end to the dinosaur era. This is the first attempt in the world to apply three-component particle image velocimetry (3-D PIV) to measure the trajectory of the entire ejecta curtain simultaneously with the fluid structure resulting from impact dynamics. The science learned in these experiments will build understanding in the entire impact process by simultaneously measuring both ejecta and atmospheric mechanics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballouz, Ronald-Louis; Richardson, Derek C.; Morishima, Ryuji

We study the B ring’s complex optical depth structure. The source of this structure may be the complex dynamics of the Keplerian shear and the self-gravity of the ring particles. The outcome of these dynamic effects depends sensitively on the collisional and physical properties of the particles. Two mechanisms can emerge that dominate the macroscopic physical structure of the ring: self-gravity wakes and viscous overstability. Here we study the interplay between these two mechanisms by using our recently developed particle collision method that allows us to better model the inter-particle contact physics. We find that for a constant ring surfacemore » density and particle internal density, particles with rough surfaces tend to produce axisymmetric ring features associated with the viscous overstability, while particles with smoother surfaces produce self-gravity wakes.« less

The Fermi Large Area Telescope on Orbit: Event Classification, Instrument Response Functions, and Calibration

DTIC Science & Technology

2012-11-01

Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology , Department of Physics and SLAC National Accelerator...Laboratory, Stanford University, Stanford, CA 94305, USA; echarles@slac.stanford.edu 3 Department of Physics, Center for Cosmology and Astro-Particle Physics

PREFACE: 14th Annual International Astrophysics Conference: Linear and Nonlinear Particle Energization throughout the Heliosphere and Beyond

NASA Astrophysics Data System (ADS)

Zank, G. P.

2015-09-01

The 14th Annual International Astrophysics Conference was held at the Sheraton Tampa Riverwalk Hotel, Tampa, Florida, USA, during the week of 19-24 April 2015. The meeting drew some 75 participants from all over the world, representing a wide range of interests and expertise in the energization of particles from the perspectives of theory, modelling and simulations, and observations. The theme of the meeting was "Linear and Nonlinear Particle Energization throughout the Heliosphere and Beyond." Energetic particles are ubiquitous to plasma environments, whether collisionless such as the supersonic solar wind, the magnetospheres of planets, the exospheres of nonmagnetized planets and comets, the heliospheric-local interstellar boundary regions, interstellar space and supernova remnant shocks, and stellar wind boundaries. Energetic particles are found too in more collisional regions such as in the solar corona, dense regions of the interstellar medium, accretion flows around stellar objects, to name a few. Particle acceleration occurs wherever plasma boundaries, magnetic and electric fields, and turbulence are present. The meeting addressed the linear and nonlinear physical processes underlying the variety of particle acceleration mechanisms, the role of particle acceleration in shaping different environments, and acceleration processes common to different regions. Both theory and observations were addressed with a view to encouraging crossdisciplinary fertilization of ideas, concepts, and techniques. The meeting addressed all aspects of particle acceleration in regions ranging from the Sun to the interplanetary medium to magnetospheres, exospheres, and comets, the boundaries of the heliosphere, and beyond to supernova remnant shocks, galactic jets, stellar winds, accretion flows, and more. The format of the meeting included 25-minute presentations punctuated by two 40-minute talks, one by Len Fisk that provided an historical overview of particle acceleration in the heliosphere (see the paper by Fisk, L., 50 Years of Research on Particle Acceleration in the Heliosphere, in this volume), and another by Len Burlaga, who presented a summary of the exciting new interstellar medium magnetic field observations being returned by Voyager 1 (see the paper by Burlaga, L., Voyager Observations of the Magnetic Field in the Heliosheath and the LISM, in this volume).

Educational Information

Science.gov Websites

PDG Homepage Link Educational Information Particle Adventure Image CPEP Image Enjoy our interactive web feature: The Particle Adventure Contemporary Physics Education Projects: Educational materials educational sites on particle physics Copyright information: This page and all following and associated are

Perspectives on the 2010 Nobel Prize in physics for graphene.

PubMed

Dresselhaus, Mildred S; Araujo, Paulo T

2010-11-23

The 2010 Nobel Prize in physics was awarded to Andre Geim and Konstantin Novoselov for their groundbreaking experiments regarding the two-dimensional material graphene. Some personal perspectives about this award are presented.

Assessment of 6th Grade Elementary School Students, Their Parents' and Branch Teachers' Perspective on Physical Education Classes

ERIC Educational Resources Information Center

Boyraz, Sirin; Ozbar, Nurper; Yetgin, Meral Kucuk; Koksalan, Burke

2015-01-01

A total of 437 volunteers including 54 teachers, 218 6th grade students and 102 parents from Beykoz Elementary Schools participated in this study to understand the perspectives of students, families and teachers on Physical Education classes. The perspectives of students, families and teachers of other branches are identified by survey method.…

Review of Particle Physics

NASA Astrophysics Data System (ADS)

Beringer, J.; Arguin, J.-F.; Barnett, R. M.; Copic, K.; Dahl, O.; Groom, D. E.; Lin, C.-J.; Lys, J.; Murayama, H.; Wohl, C. G.; Yao, W.-M.; Zyla, P. A.; Amsler, C.; Antonelli, M.; Asner, D. M.; Baer, H.; Band, H. R.; Basaglia, T.; Bauer, C. W.; Beatty, J. J.; Belousov, V. I.; Bergren, E.; Bernardi, G.; Bertl, W.; Bethke, S.; Bichsel, H.; Biebel, O.; Blucher, E.; Blusk, S.; Brooijmans, G.; Buchmueller, O.; Cahn, R. N.; Carena, M.; Ceccucci, A.; Chakraborty, D.; Chen, M.-C.; Chivukula, R. S.; Cowan, G.; D'Ambrosio, G.; Damour, T.; de Florian, D.; de Gouvêa, A.; DeGrand, T.; de Jong, P.; Dissertori, G.; Dobrescu, B.; Doser, M.; Drees, M.; Edwards, D. A.; Eidelman, S.; Erler, J.; Ezhela, V. V.; Fetscher, W.; Fields, B. D.; Foster, B.; Gaisser, T. K.; Garren, L.; Gerber, H.-J.; Gerbier, G.; Gherghetta, T.; Golwala, S.; Goodman, M.; Grab, C.; Gritsan, A. V.; Grivaz, J.-F.; Grünewald, M.; Gurtu, A.; Gutsche, T.; Haber, H. E.; Hagiwara, K.; Hagmann, C.; Hanhart, C.; Hashimoto, S.; Hayes, K. G.; Heffner, M.; Heltsley, B.; Hernández-Rey, J. J.; Hikasa, K.; Höcker, A.; Holder, J.; Holtkamp, A.; Huston, J.; Jackson, J. D.; Johnson, K. F.; Junk, T.; Karlen, D.; Kirkby, D.; Klein, S. R.; Klempt, E.; Kowalewski, R. V.; Krauss, F.; Kreps, M.; Krusche, B.; Kuyanov, Yu. V.; Kwon, Y.; Lahav, O.; Laiho, J.; Langacker, P.; Liddle, A.; Ligeti, Z.; Liss, T. M.; Littenberg, L.; Lugovsky, K. S.; Lugovsky, S. B.; Mannel, T.; Manohar, A. V.; Marciano, W. J.; Martin, A. D.; Masoni, A.; Matthews, J.; Milstead, D.; Miquel, R.; Mönig, K.; Moortgat, F.; Nakamura, K.; Narain, M.; Nason, P.; Navas, S.; Neubert, M.; Nevski, P.; Nir, Y.; Olive, K. A.; Pape, L.; Parsons, J.; Patrignani, C.; Peacock, J. A.; Petcov, S. T.; Piepke, A.; Pomarol, A.; Punzi, G.; Quadt, A.; Raby, S.; Raffelt, G.; Ratcliff, B. N.; Richardson, P.; Roesler, S.; Rolli, S.; Romaniouk, A.; Rosenberg, L. J.; Rosner, J. L.; Sachrajda, C. T.; Sakai, Y.; Salam, G. P.; Sarkar, S.; Sauli, F.; Schneider, O.; Scholberg, K.; Scott, D.; Seligman, W. G.; Shaevitz, M. H.; Sharpe, S. R.; Silari, M.; Sjöstrand, T.; Skands, P.; Smith, J. G.; Smoot, G. F.; Spanier, S.; Spieler, H.; Stahl, A.; Stanev, T.; Stone, S. L.; Sumiyoshi, T.; Syphers, M. J.; Takahashi, F.; Tanabashi, M.; Terning, J.; Titov, M.; Tkachenko, N. P.; Törnqvist, N. A.; Tovey, D.; Valencia, G.; van Bibber, K.; Venanzoni, G.; Vincter, M. G.; Vogel, P.; Vogt, A.; Walkowiak, W.; Walter, C. W.; Ward, D. R.; Watari, T.; Weiglein, G.; Weinberg, E. J.; Wiencke, L. R.; Wolfenstein, L.; Womersley, J.; Woody, C. L.; Workman, R. L.; Yamamoto, A.; Zeller, G. P.; Zenin, O. V.; Zhang, J.; Zhu, R.-Y.; Harper, G.; Lugovsky, V. S.; Schaffner, P.

2012-07-01

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, Vcb & Vub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter.A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov/.The 2012 edition of Review of Particle Physics is published for the Particle Data Group as article 010001 in volume 86 of Physical Review D.This edition should be cited as: J. Beringer et al. (Particle Data Group), Phys. Rev. D 86, 010001 (2012).

God particles in the perspective of The AlQuran Surah Yunus: 61 and modern science

NASA Astrophysics Data System (ADS)

Jumini, Sri

2017-01-01

The Qur'an is the book of Allah revealed to guide human beings, settting the rules of life to enable them to achieve happiness in this world and hereafter. The Qur'an has mentioned various scientific nature detailly and accurately so we are able to find new knowledge which is previously unknown by human being. One was about the God particle (Higgs Boson). This article aims to provide a deeper understanding of the concept of the Higgs Boson, the Higgs Boson explained this concept in detail relatated to 1) Perspective of science 2) Perspective of Al-Qur'an 3) Development of technology or science and technology. This study is a qualitative research using library research (library research) that examines and analyzes the books relating directly or indirectly. The results of the analysis states that 1) The concept of the Higgs Boson particle in terms of basic science is also the reason why almost all elementary particles have a greater mass, 2) The concept of the Higgs Boson in the Qur'an is implied from the results of the comparison interpretation of the commentators in Surah Yunus paragraph 61 related to Atom concepts and smaller particles theory of (Higgs Boson), interpretation of Al-Maraghi, and Al-Misbah. 3) The concept of the Higgs Boson in science and technology provide the most advance technology and it is the greatest achievement in the world of science and technology.

Review of particle physics

DOE PAGES

Olive, K. A.

2016-10-01

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders,more » Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.« less

Particle astronomy and particle physics from the moon - The particle observatory

NASA Technical Reports Server (NTRS)

Wilson, Thomas L.

1990-01-01

Promising experiments from the moon using particle detectors are discussed, noting the advantage of the large flux collecting power Pc offered by the remote, stable environment of a lunar base. An observatory class of particle experiments is presented, based upon proposals at NASA's recent Stanford workshop. They vary from neutrino astronomy, particle astrophysics, and cosmic ray experiments to space physics and fundamental physics experiments such as proton decay and 'table-top' arrays. This research is background-limited on earth, and it is awkward and unrealistic in earth orbit, but is particularly suited for the moon where Pc can be quite large and the instrumentation is not subject to atmospheric erosion as it is (for large t) in low earth orbit.

Review of particle physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olive, K. A.

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders,more » Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.« less

Fermilab | Science at Fermilab | Experiments & Projects | Cosmic Frontier

Science.gov Websites

Proposed Projects and Experiments Fermilab's Tevatron Questions for the Universe Theory Computing High Answers Submit a Question Frontiers of Particle Physics Benefits to Society Benefits to Society Medicine Inquiring Minds Questions About Physics Other High-Energy Physics Sites More About Particle Physics Library

Advanced Level Physics Students' Conceptions of Quantum Physics.

ERIC Educational Resources Information Center

Mashhadi, Azam

This study addresses questions about particle physics that focus on the nature of electrons. Speculations as to whether they are more like particles or waves or like neither illustrate the difficulties with which students are confronted when trying to incorporate the concepts of quantum physics into their overall conceptual framework. Such…

Inerton fields: very new ideas on fundamental physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasnoholovets, Volodymyr

2010-12-22

Modern theories of everything, or theories of the grand unification of all physical interactions, try to describe the whole world starting from the first principles of quantum theory. However, the first principles operate with undetermined notions, such as the wave {psi}-function, particle, lepton and quark, de Broglie and Compton wavelengths, mass, electric charge, spin, electromagnetic field, photon, gravitation, physical vacuum, space, etc. From a logical point of view this means that such modern approach to the theory of everything is condemned to failure... Thus, what should we suggest to improve the situation? It seems quite reasonable to develop initially amore » theory of something, which will be able to clarify the major fundamental notions (listed above) that physics operates with every day. What would be a starting point in such approach? Of course a theory of space as such, because particles and all physical fields emerge just from space. After that, when a particle and fields (and hence the fields' carriers) are well defined and introduced in the well defined physical space, different kinds of interactions can be proposed and investigated. Moreover, we must also allow for a possible interaction of a created particle with the space that generated the appearance of the particle. The mathematical studies of Michel Bounias and the author have shown what the real physical space is, how the space is constituted, how it is arranged and what its elements are. Having constructed the real physical space we can then derive whatever we wish, in particular, such basic notions as mass, particle and charge. How are mechanics of such objects (a massive particle, a charged massive particle) organised? The appropriate theory of motion has been called a sub microscopic mechanics of particles, which is developed in the real physical space, not an abstract phase space, as conventional quantum mechanics does. A series of questions arise: can these two mechanics (submicroscopic and conventional quantum mechanics) be unified?, what can such unification bring new for us?, can such submicroscopic mechanics be a starting point for the derivation of the phenomenon of gravity?, can this new theory be a unified physical theory?, does the theory allow experimental verification? These major points have been clarified in detail. And, perhaps, the most intriguing aspect of the theory is the derivation of a new physical field associated with the notion of mass (or rather inertia of a particle, which has been called the inerton field and which represents a real sense of the particle's wave {psi}-function). This field emerges by analogy with the electromagnetic field associated with the notion of the electric charge. Yes, the postulated inerton field has being tested in a series of different experiments. Even more, the inerton field might have a number of practical applications...« less

Revealing School Counselors' Perspectives on Using Physical Activity and Consulting with Coaches

ERIC Educational Resources Information Center

Hayden, Laura; Silva, Meghan Ray; Gould, Kaitlin

2018-01-01

This study reveals school counselors' perspectives on using physical activity and a consultative process with coaches to provide school-based support for youth. Emerging from this exploration are ways that school-based physical activity might be used to help students develop life skills and to remove barriers to systemic integration of…

Development of students' interest in particle physics as effect of participating in a Masterclass

NASA Astrophysics Data System (ADS)

Gedigk, Kerstin; Pospiech, Gesche

2016-05-01

The International Hands On Particle Physics Masterclasses are enjoying increasing popularity worldwide every year. In Germany a national program was brought to live in 2010, which offers these appreciated events to whole classes or courses of high school students all over the year. These events were evaluated concerning the issues of students' interest in particle physics and their perception of the events. How several interest variables interact with each other and the perception of the events is answered by structural equation modelling (sect. 5.2). The results give information about the events' effects on the students' interest development in particle physics, show which event features are important ( e.g. the authenticity) and give information about practical approaches to improve the effects of the Masterclasses. Section 5.3 deals with a group of participants which have a high interest in particle physics 6-8 weeks after the participation. The number of these students is remarkable large, with 26% of all participants. The investigation of this group shows that the Masterclass participation has the same positive effect on both sexes and all levels of physics education.

Physics and astrophysics from a lunar base; Proceedings of the 1st NASA Workshop, Stanford, CA, May 19, 20, 1989

NASA Technical Reports Server (NTRS)

Potter, A. E. (Editor); Wilson, T. L. (Editor)

1990-01-01

The present conference on physics and astrophysics from a lunar base encompasses space physics, cosmic ray physics, neutrino physics, experiments in gravitation and general relativity, gravitational radiation physics, cosmic background radiation, particle astrophysics, surface physics, and the physics of gamma rays and X-rays. Specific issues addressed include space-plasma physics research at a lunar base, prospects for neutral particle imaging, the atmosphere as particle detector, medium- and high-energy neutrino physics from a lunar base, muons on the moon, a search for relic supernovae antineutrinos, and the use of clocks in satellites orbiting the moon to test general relativity. Also addressed are large X-ray-detector arrays for physics experiments on the moon, and the measurement of proton decay, arcsec-source locations, halo dark matter and elemental abundances above 10 exp 15 eV at a lunar base.

What Physical Health Means to Me: Perspectives of People with Mental Illness.

PubMed

Happell, Brenda; Ewart, Stephanie B; Platania-Phung, Chris; Bocking, Julia; Scholz, Brett; Stanton, Robert

2016-12-01

There are significant inequalities in physical health and life expectancy between people with and without a mental illness. Understanding perspectives of people with mental illness on personal meanings of physical health is essential to ensuring health services are aligned with consumer understandings, needs, and values. A qualitative exploratory study was undertaken involving focus groups with 31 consumers in The Australian Capital Territory, Australia. Participants were asked: "What does physical health mean to you?" Thematic analysis was applied to interview transcripts. Five themes are discussed, representing different emphases in the meaning of physical health: (1) physical and mental are interconnected, (2) absence of disease, (3) moving the body, (4) struggling for healthy diet, and (5) functioning and participation. Physical pain was a difficulty that arose across these themes. Mental health consumers see physical health as always connected with well-being. Nurses would benefit from been informed by consumer understandings of physical health. In addition, there should be more attention to quality of life measures of people with mental illness as these are more congruent with consumer perspectives on physical health than biomedical measures.

PARTICLE PHYSICS: CERN Collider Glimpses Supersymmetry--Maybe.

PubMed

Seife, C

2000-07-14

Last week, particle physicists at the CERN laboratory in Switzerland announced that by smashing together matter and antimatter in four experiments, they detected an unexpected effect in the sprays of particles that ensued. The anomaly is subtle, and physicists caution that it might still be a statistical fluke. If confirmed, however, it could mark the long-sought discovery of a whole zoo of new particles--and the end of a long-standing model of particle physics.

Biomedical Nanomagnetics: A Spin Through Possibilities in Imaging, Diagnostics, and Therapy

PubMed Central

Krishnan, Kannan M.

2010-01-01

Biomedical nanomagnetics is a multidisciplinary area of research in science, engineering and medicine with broad applications in imaging, diagnostics and therapy. Recent developments offer exciting possibilities in personalized medicine provided a truly integrated approach, combining chemistry, materials science, physics, engineering, biology and medicine, is implemented. Emphasizing this perspective, here we address important issues for the rapid development of the field, i.e., magnetic behavior at the nanoscale with emphasis on the relaxation dynamics, synthesis and surface functionalization of nanoparticles and core-shell structures, biocompatibility and toxicity studies, biological constraints and opportunities, and in vivo and in vitro applications. Specifically, we discuss targeted drug delivery and triggered release, novel contrast agents for magnetic resonance imaging, cancer therapy using magnetic fluid hyperthermia, in vitro diagnostics and the emerging magnetic particle imaging technique, that is quantitative and sensitive enough to compete with established imaging methods. In addition, the physics of self-assembly, which is fundamental to both biology and the future development of nanoscience, is illustrated with magnetic nanoparticles. It is shown that various competing energies associated with self-assembly converge on the nanometer length scale and different assemblies can be tailored by varying particle size and size distribution. Throughout this paper, while we discuss our recent research in the broad context of the multidisciplinary literature, we hope to bridge the gap between related work in physics/chemistry/engineering and biology/medicine and, at the same time, present the essential concepts in the individual disciplines. This approach is essential as biomedical nanomagnetics moves into the next phase of innovative translational research with emphasis on development of quantitative in vivo imaging, targeted and triggered drug release, and image guided therapy including validation of delivery and therapy response. PMID:20930943

Theoretical analysis of the influence of aerosol size distribution and physical activity on particle deposition pattern in human lungs.

PubMed

Voutilainen, Arto; Kaipio, Jari P; Pekkanen, Juha; Timonen, Kirsi L; Ruuskanen, Juhani

2004-01-01

A theoretical comparison of modeled particle depositions in the human respiratory tract was performed by taking into account different particle number and mass size distributions and physical activity in an urban environment. Urban-air data on particulate concentrations in the size range 10 nm-10 microm were used to estimate the hourly average particle number and mass size distribution functions. The functions were then combined with the deposition probability functions obtained from a computerized ICRP 66 deposition model of the International Commission on Radiological Protection to calculate the numbers and masses of particles deposited in five regions of the respiratory tract of a male adult. The man's physical activity and minute ventilation during the day were taken into account in the calculations. Two different mass and number size distributions of aerosol particles with equal (computed) <10 microm particle mass concentrations gave clearly different deposition patterns in the central and peripheral regions of the human respiratory tract. The deposited particle numbers and masses were much higher during the day (0700-1900) than during the night (1900-0700) because an increase in physical activity and ventilation were temporally associated with highly increased traffic-derived particles in urban outdoor air. In future analyses of the short-term associations between particulate air pollution and health, it would not only be important to take into account the outdoor-to-indoor penetration of different particle sizes and human time-activity patterns, but also actual lung deposition patterns and physical activity in significant microenvironments.

Press Room

Science.gov Websites

Science at Fermilab Fermilab and the Higgs Boson Frontiers of Particle Physics Experiments & Projects Frontiers of Particle Physics Benefits to Society Contacting Fermilab General Contact Information Email -12 Programs Lederman Science Center Saturday Morning Physics Cooperative Education Program

U.C. Davis high energy particle physics research: Technical progress report -- 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Summaries of progress made for this period is given for each of the following areas: (1) Task A--Experiment, H1 detector at DESY; (2) Task C--Experiment, AMY detector at KEK; (3) Task D--Experiment, fixed target detectors at Fermilab; (4) Task F--Experiment, PEP detector at SLAC and pixel detector; (5) Task B--Theory, particle physics; and (6) Task E--Theory, particle physics.

A facility to search for hidden particles at the CERN SPS: the SHiP physics case.

PubMed

Alekhin, Sergey; Altmannshofer, Wolfgang; Asaka, Takehiko; Batell, Brian; Bezrukov, Fedor; Bondarenko, Kyrylo; Boyarsky, Alexey; Choi, Ki-Young; Corral, Cristóbal; Craig, Nathaniel; Curtin, David; Davidson, Sacha; de Gouvêa, André; Dell'Oro, Stefano; deNiverville, Patrick; Bhupal Dev, P S; Dreiner, Herbi; Drewes, Marco; Eijima, Shintaro; Essig, Rouven; Fradette, Anthony; Garbrecht, Björn; Gavela, Belen; Giudice, Gian F; Goodsell, Mark D; Gorbunov, Dmitry; Gori, Stefania; Grojean, Christophe; Guffanti, Alberto; Hambye, Thomas; Hansen, Steen H; Helo, Juan Carlos; Hernandez, Pilar; Ibarra, Alejandro; Ivashko, Artem; Izaguirre, Eder; Jaeckel, Joerg; Jeong, Yu Seon; Kahlhoefer, Felix; Kahn, Yonatan; Katz, Andrey; Kim, Choong Sun; Kovalenko, Sergey; Krnjaic, Gordan; Lyubovitskij, Valery E; Marcocci, Simone; Mccullough, Matthew; McKeen, David; Mitselmakher, Guenakh; Moch, Sven-Olaf; Mohapatra, Rabindra N; Morrissey, David E; Ovchynnikov, Maksym; Paschos, Emmanuel; Pilaftsis, Apostolos; Pospelov, Maxim; Reno, Mary Hall; Ringwald, Andreas; Ritz, Adam; Roszkowski, Leszek; Rubakov, Valery; Ruchayskiy, Oleg; Schienbein, Ingo; Schmeier, Daniel; Schmidt-Hoberg, Kai; Schwaller, Pedro; Senjanovic, Goran; Seto, Osamu; Shaposhnikov, Mikhail; Shchutska, Lesya; Shelton, Jessie; Shrock, Robert; Shuve, Brian; Spannowsky, Michael; Spray, Andy; Staub, Florian; Stolarski, Daniel; Strassler, Matt; Tello, Vladimir; Tramontano, Francesco; Tripathi, Anurag; Tulin, Sean; Vissani, Francesco; Winkler, Martin W; Zurek, Kathryn M

2016-12-01

This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.

Swimming droplets driven by a surface wave

PubMed Central

Ebata, Hiroyuki; Sano, Masaki

2015-01-01

Self-propelling motion is ubiquitous for soft active objects such as crawling cells, active filaments, and liquid droplets moving on surfaces. Deformation and energy dissipation are required for self-propulsion of both living and non-living matter. From the perspective of physics, searching for universal laws of self-propelled motions in a dissipative environment is worthwhile, regardless of the objects' details. In this article, we propose a simple experimental system that demonstrates spontaneous migration of a droplet under uniform mechanical agitation. As we vary control parameters, spontaneous symmetry breaking occurs sequentially, and cascades of bifurcations of the motion arise. Equations describing deformable particles and hydrodynamic simulations successfully describe all of the observed motions. This system should enable us to improve our understanding of spontaneous motions of self-propelled objects. PMID:25708871

Swimming droplets driven by a surface wave

NASA Astrophysics Data System (ADS)

Ebata, Hiroyuki; Sano, Masaki

2015-02-01

Self-propelling motion is ubiquitous for soft active objects such as crawling cells, active filaments, and liquid droplets moving on surfaces. Deformation and energy dissipation are required for self-propulsion of both living and non-living matter. From the perspective of physics, searching for universal laws of self-propelled motions in a dissipative environment is worthwhile, regardless of the objects' details. In this article, we propose a simple experimental system that demonstrates spontaneous migration of a droplet under uniform mechanical agitation. As we vary control parameters, spontaneous symmetry breaking occurs sequentially, and cascades of bifurcations of the motion arise. Equations describing deformable particles and hydrodynamic simulations successfully describe all of the observed motions. This system should enable us to improve our understanding of spontaneous motions of self-propelled objects.

Study of kinematic observables sentitive to the Higgs boson production channel in pp → Hjj process

NASA Astrophysics Data System (ADS)

Belyaev, N.; Konoplich, R.; Prokofiev, K.

2017-12-01

After the Higgs boson discovery at the LHC, a lot of additional measurements should be performed to understand in details the properties of the observed particle. These measurements include cross sections measurements, couplings measurements, studies of the interaction vertex structures etc. One of the most perspective subjects to study is the kinematics of the production jets, associated with the Higgs boson. It is demonstrated, that the kinematic correlations of such jets can be used to distinguish different production channels of Higgs boson: gluon-gluon fusion (ggF) and vector boson fusion (VBF). Such separation plays an important role because possible beyond the Standard Model contributions in ggF and VBF channels lead to different effects, which should be taken into account in searches for BSM physics.

The Mainz Neutrino Mass Experiment - New Results and Perspectives

NASA Astrophysics Data System (ADS)

Bonn, J.; Bornschein, B.; Bornschein, L.; Fickinger, L.; Flatt, B.; Kraus, Ch.; Otten, E. W.; Schall, J. P.; Ulrich, H.; Weinheimer, Ch.; Kazachenko, O.; Kovalik, A.

2002-12-01

Non-zero neutrino masses, strongly favoured by the recent atmospheric and solar neutrino experiments, have strong consequences for particle physics as well as for astrophysics and cosmology. The investigation of the tritium β spectrum near its endpoint measures the mass of the "electron neutrino m(νe)" (m2 (ν e ) = Σ |Uei |2 mi2 with neutrino mixing matrix U and neutrino mass eigenstates mi) and is the most sensitive of these so-called direct methods providing information complementary to the searches for neutrinoless double β decay. Tritium β decay is the ideal method to distinguish between hierarchical and degenerate neutrino mass models. Furthermore, neutrino masses up to about 1 eV/c2 are especially interesting for cosmology because of their contribution to the missing dark matter in the universe...

Two Higgs doublet models augmented by a scalar colour octet

DOE PAGES

Cheng, Li; Valencia, German

2016-09-13

The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet models (2HDM). In this paper we extend those studies to include constraints on the one loop couplings of the Higgs to gluons and photons. These couplings are particularly sensitive to the existence of new coloured particles that are hard to detect otherwise and we use them to constrain a 2HDM augmented with a colour-octet scalar, a possibility motivated bymore » minimal flavour violation. We first study theoretical constraints on this model and then compare them with LHC measurements.« less

Two Higgs doublet models augmented by a scalar colour octet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Li; Valencia, German

The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet models (2HDM). In this paper we extend those studies to include constraints on the one loop couplings of the Higgs to gluons and photons. These couplings are particularly sensitive to the existence of new coloured particles that are hard to detect otherwise and we use them to constrain a 2HDM augmented with a colour-octet scalar, a possibility motivated bymore » minimal flavour violation. We first study theoretical constraints on this model and then compare them with LHC measurements.« less

Theoretical Studies of Alfven Waves and Energetic Particle Physics in Fusion Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Liu

This report summarizes major theoretical findings in the linear as well as nonlinear physics of Alfvén waves and energetic particles in magnetically confined fusion plasmas. On the linear physics, a variational formulation, based on the separation of singular and regular spatial scales, for drift-Alfvén instabilities excited by energetic particles is established. This variational formulation is then applied to derive the general fishbone-like dispersion relations corresponding to the various Alfvén eigenmodes and energetic-particle modes. It is further employed to explore in depth the low-frequency Alfvén eigenmodes and demonstrate the non-perturbative nature of the energetic particles. On the nonlinear physics, new novelmore » findings are obtained on both the nonlinear wave-wave interactions and nonlinear wave-energetic particle interactions. It is demonstrated that both the energetic particles and the fine radial mode structures could qualitatively affect the nonlinear evolution of Alfvén eigenmodes. Meanwhile, a theoretical approach based on the Dyson equation is developed to treat self-consistently the nonlinear interactions between Alfvén waves and energetic particles, and is then applied to explain simulation results of energetic-particle modes. Relevant list of journal publications on the above findings is also included.« less

Particle physics for primary schools—enthusing future physicists

NASA Astrophysics Data System (ADS)

Pavlidou, M.; Lazzeroni, C.

2016-09-01

In recent years, the realisation that children make decisions and choices about subjects they like in primary school, became widely understood. For this reason academic establishments focus some of their public engagement activities towards the younger ages. Taking advantage of Professor Lazzeroni’s long-standing experience in particle physics research, during the last academic year we designed and trialled a particle physics workshop for primary schools. The workshop allows young children (ages 8-11) to learn the world of fundamental particles, use creative design to make particle models. The workshop has already been trialled in many primary schools, receiving very positive evaluation. The initial resources were reviewed and improved, based on the feedback received from school teachers and communicators.

Biofeedback in Partial Weight Bearing: Usability of Two Different Devices from a Patient's and Physical Therapist's Perspective.

PubMed

van Lieshout, Remko; Pisters, Martijn F; Vanwanseele, Benedicte; de Bie, Rob A; Wouters, Eveline J; Stukstette, Mirelle J

2016-01-01

Partial weight bearing is frequently instructed by physical therapists in patients after lower-limb trauma or surgery. The use of biofeedback devices seems promising to improve the patient's compliance with weight-bearing instructions. SmartStep and OpenGo-Science are biofeedback devices that provide real-time feedback. For a successful implementation, usability of the devices is a critical aspect and should be tested from a user's perspective. To describe the usability from the physical therapists' and a patients' perspective of Smartstep and OpenGo-Science to provide feedback on partial weight bearing during supervised rehabilitation of patients after lower-limb trauma or surgery. In a convergent mixed-methods design, qualitative and quantitative data were collected. Usability was subdivided into user performance, satisfaction and acceptability. Patients prescribed with partial weight bearing and their physical therapists were asked to use SmartStep and OpenGo-Science during supervised rehabilitation. Usability was qualitatively tested by a think-aloud method and a semi-structured interview and quantitatively tested by the System-Usability-Scale (SUS) and closed questions. For the qualitative data thematic content analyses were used. Nine pairs of physical therapists and their patients participated. The mean SUS scores for patients and physical therapists were for SmartStep 70 and 53, and for OpenGo-Science 79 and 81, respectively. Scores were interpreted with the Curved Grading Scale. The qualitative data showed that there were mixed views and perceptions from patients and physical therapists on satisfaction and acceptability. This study gives insight in the usability of two biofeedback devices from the patient's and physical therapist's perspective. The overall usability from both perspectives seemed to be acceptable for OpenGo-Science. For SmartStep, overall usability seemed only acceptable from the patient's perspective. The study findings could help clinicians to decide which biofeedback device is appropriate for their given situation and provide information for future development of biofeedback devices.

Martinus Veltman, the Electroweak Theory, and Elementary Particle Physics

Science.gov Websites

Particle Physics Resources with Additional Information Martinus Veltman Courtesy University of Michigan Martinus J.G. Veltman, the John D. MacArthur Professor Emeritus of Physics at the University of Michigan , was awarded the 1999 Nobel Prize in physics "for elucidating the quantum structure of electroweak

Lagrangian particles with mixing. I. Simulating scalar transport

NASA Astrophysics Data System (ADS)

Klimenko, A. Y.

2009-06-01

The physical similarity and mathematical equivalence of continuous diffusion and particle random walk forms one of the cornerstones of modern physics and the theory of stochastic processes. The randomly walking particles do not need to posses any properties other than location in physical space. However, particles used in many models dealing with simulating turbulent transport and turbulent combustion do posses a set of scalar properties and mixing between particle properties is performed to reflect the dissipative nature of the diffusion processes. We show that the continuous scalar transport and diffusion can be accurately specified by means of localized mixing between randomly walking Lagrangian particles with scalar properties and assess errors associated with this scheme. Particles with scalar properties and localized mixing represent an alternative formulation for the process, which is selected to represent the continuous diffusion. Simulating diffusion by Lagrangian particles with mixing involves three main competing requirements: minimizing stochastic uncertainty, minimizing bias introduced by numerical diffusion, and preserving independence of particles. These requirements are analyzed for two limited cases of mixing between two particles and mixing between a large number of particles. The problem of possible dependences between particles is most complicated. This problem is analyzed using a coupled chain of equations that has similarities with Bogolubov-Born-Green-Kirkwood-Yvon chain in statistical physics. Dependences between particles can be significant in close proximity of the particles resulting in a reduced rate of mixing. This work develops further ideas introduced in the previously published letter [Phys. Fluids 19, 031702 (2007)]. Paper I of this work is followed by Paper II [Phys. Fluids 19, 065102 (2009)] where modeling of turbulent reacting flows by Lagrangian particles with localized mixing is specifically considered.

An Exploratory Study of Elementary Classroom Teachers' Physical Activity Promotion from a Social Learning Perspective

ERIC Educational Resources Information Center

Webster, Collin A.; Buchan, Heather; Perreault, Melanie; Doan, Rob; Doutis, Panayiotis; Weaver, Robert Glenn

2015-01-01

Despite its recommended use, physical activity promotion in the academic classroom (PAPAC) has received little attention in terms of the factors that help to facilitate it. In this study, a social learning perspective was adopted to examine the role of physical activity biographies in generalist classroom teachers' (CTs) PAPAC. CTs (N = 213) were…

Perspectives on the Contribution of Social Science to Adapted Physical Activity: Looking Forward, Looking Back

ERIC Educational Resources Information Center

Causgrove Dunn, Janice; Cairney, John; Zimmer, Chantelle

2016-01-01

In this article, we reflect on the contributions of the social sciences to the field of adapted physical activity by examining the theories and methods that have been adopted from the social science disciplines. To broaden our perspective on adapted physical activity and provide new avenues for theoretical and empirical exploration, we discuss and…

Does Physical Environment Contribute to Basic Psychological Needs? A Self-Determination Theory Perspective on Learning in the Chemistry Laboratory

ERIC Educational Resources Information Center

Sjöblom, Kirsi; Mälkki, Kaisu; Sandström, Niclas; Lonka, Kirsti

2016-01-01

The role of motivation and emotions in learning has been extensively studied in recent years; however, research on the role of the physical environment still remains scarce. This study examined the role of the physical environment in the learning process from the perspective of basic psychological needs. Although self-determination theory stresses…

"I Could Do with a Pair of Wings": Perspectives on Physical Activity, Bodies and Health from Young Australian Children

ERIC Educational Resources Information Center

Macdonald, Doune; Rodger, Sylvia; Abbott, Rebecca; Ziviani, Jenny; Jones, Judy

2005-01-01

There is little research that reports children's perspectives on physical activity, bodies and health. This paper, drawn from a larger multi-method study on physical activity in the lives of seven- and eight-year-old Australian children, attempts to "give a voice" to 13 children's views. Interviews focused on children's activity…

Plato's Ideas and the Theories of Modern Particle Physics: Amazing Parallels

NASA Astrophysics Data System (ADS)

Machleidt, Ruprecht

2006-05-01

It is generally known that the question, ``What are the most elementary particles that all matter is made from?'', was already posed in the antiquity. The Greek natural philosophers Leucippus and Democritus were the first to suggest that all matter was made from atoms. Therefore, most people perceive them as the ancient fathers of elementary particle physics. However, this perception is wrong. Modern particle physics is not just a simple atomism. The characteristic point of modern particle theory is that it is concerned with the symmetries underlying the particles we discover in experiment. More than 2000 years ago, a similar idea was already advanced by the Greek philosopher Plato in his dialogue Timaeus: Geometric symmetries generate the atoms from just a few even more elementary items. Plato's vision is amazingly close to the ideas of modern particle theory. This fact, which is unfortunately little known, has been pointed out repeatedly by Werner Heisenberg.

Manipulation of particles by weak forces

NASA Technical Reports Server (NTRS)

Adler, M. S.; Savkar, S. D.; Summerhayes, H. R.

1972-01-01

Quantitative relations between various force fields and their effects on the motion of particles of various sizes and physical characteristics were studied. The forces considered were those derived from light, heat, microwaves, electric interactions, magnetic interactions, particulate interactions, and sound. A physical understanding is given of the forces considered as well as formulae which express how the size of the force depends on the physical and electrical properties of the particle. The drift velocity in a viscous fluid is evaluated as a function of initial acceleration and the effects of thermal random motion are considered. A means of selectively sorting or moving particles by choosing a force system and/or environment such that the particle of interest reacts uniquely was developed. The forces considered and a demonstration of how the initial acceleration, drift velocity, and ultimate particle density distribution is affected by particle, input, and environmental parameters are tabulated.

The Principal and Nurse Perspective on Gaps in Asthma Care and Barriers to Physical Activity in New York City Schools: A Qualitative Study

ERIC Educational Resources Information Center

Cain, Agnieszka; Reznik, Marina

2018-01-01

Background: School officials and nurses play an important role in facilitating asthma management in schools. Little is known about their perspectives on in-school asthma management and barriers to physical activity (PA) at school. Aims: The goal of this study is to explore school officials' and nurses' perspectives on asthma care and barriers to…

Quarks, Leptons, and Bosons: A Particle Physics Primer.

ERIC Educational Resources Information Center

Wagoner, Robert; Goldsmith, Donald

1983-01-01

Presented is a non-technical introduction to particle physics. The material is adapted from chapter 3 of "Cosmic Horizons," (by Robert Wagoner and Don Goldsmith), a lay-person's introduction to cosmology. Among the topics considered are elementary particles, forces and motion, and higher level structures. (JN)

Higgs Particle: The Origin of Mass

NASA Astrophysics Data System (ADS)

Okada, Yasuhiro

2007-11-01

The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics.

Quantum theory and Aquinas's doctrine on matter

NASA Astrophysics Data System (ADS)

Grove, Stanley F.

The Aristotelian conception of the material principle, deepened by Aquinas, is today widely misunderstood and largely alien to modern mathematical physics, despite the latter's preoccupation with matter and the spatiotemporal. The present dissertation seeks to develop a coherent understanding of matter in the Aristotelian-Thomistic sense, and to apply it to some key interpretive issues in quantum physics. I begin with a brief historical analysis of the Aristotelian, Newtonian ("classical"), and modern (quantum) approaches to physics, in order to highlight their commonality as well as their differences. Next, matter---especially prime matter---is investigated, in an Aristotelian-Thomistic perspective, under several rationes: as principle of individuation, as principle of extension or spatiality, as principle of corruptibility, as related to essence and existence, and as ground of intelligibility. An attempt is made to order these different rationes according to primordiality. A number of topics concerning the formal structure of hylomorphic being are then addressed: elementarity, virtual presence, the "dispositions of matter," entia vialia, natural minima, atomism, the nature of local motion, the plenum and instantaneous action at a distance---all with a view to their incorporation in a unified account of formed matter at or near the elementary level. Finally I take up several interpretive problems in quantum physics which were introduced early in the dissertation, and show how the material and formal principles expounded in the central chapters can render these problems intelligible. Thus I propose that wave and particle aspects in the quantum realm are related substantially rather than accidentally, and that characteristics of substantial (prime) matter and substantial form are therefore being evidenced directly at this level---in the reversibility of the wave-particle transition, in the spatial and temporal instantaneity of quantum events, and in the probabilism encountered in such phenomena. I offer related hypotheses for Heisenberg uncertainty and for quantum nonlocality. In closing, I address some strengths and weaknesses in others' work on quantum interpretation in the light of Aristotelian principles. Three Appendices explore further aspects of matter as a cosmic principle.

Review of heavy charged particle transport in MCNP6.2

NASA Astrophysics Data System (ADS)

Zieb, K.; Hughes, H. G.; James, M. R.; Xu, X. G.

2018-04-01

The release of version 6.2 of the MCNP6 radiation transport code is imminent. To complement the newest release, a summary of the heavy charged particle physics models used in the 1 MeV to 1 GeV energy regime is presented. Several changes have been introduced into the charged particle physics models since the merger of the MCNP5 and MCNPX codes into MCNP6. This paper discusses the default models used in MCNP6 for continuous energy loss, energy straggling, and angular scattering of heavy charged particles. Explanations of the physics models' theories are included as well.

Review of Heavy Charged Particle Transport in MCNP6.2

DOE PAGES

Zieb, Kristofer James Ekhart; Hughes, Henry Grady III; Xu, X. George; ...

2018-01-05

The release of version 6.2 of the MCNP6 radiation transport code is imminent. To complement the newest release, a summary of the heavy charged particle physics models used in the 1 MeV to 1 GeV energy regime is presented. Several changes have been introduced into the charged particle physics models since the merger of the MCNP5 and MCNPX codes into MCNP6. Here, this article discusses the default models used in MCNP6 for continuous energy loss, energy straggling, and angular scattering of heavy charged particles. Explanations of the physics models’ theories are included as well.

The need for a life-cycle based aging paradigm for nanomaterials: importance of real-world test systems to identify realistic particle transformations

NASA Astrophysics Data System (ADS)

Mitrano, Denise M.; Nowack, Bernd

2017-02-01

Assessing the risks of manufactured nanomaterials (MNM) has been almost exclusively focused on the pristine, as-produced materials with far fewer studies delving into more complex, real world scenarios. However, when considering a life-cycle perspective, it is clear that MNM released from commercial products during manufacturing, use and disposal are far more relevant both in terms of more realistic environmental fate and transport as well as environmental risk. The quantity in which the particles are released and their (altered) physical and chemical form should be identified and it is these metrics that should be used to assess the exposure and hazard the materials pose. The goal of this review is to (1) provide a rationale for using a life-cycle based approach when dealing with MNM transformations, (2) to elucidate the different chemical and physical forces which age and transform MNM and (3) assess the pros and cons of current analytical techniques as they pertain to the measurement of aged and transformed MNM in these complex release scenarios. Specifically, we will describe the possible transformations common MNM may undergo during the use or disposal of nano-products based on how these products will be used by the consumer by taking stock of the current nano-enabled products on the market. Understanding the impact of these transformations may help forecast the benefits and/or risks associated with the use of products containing MNM.

On the high fidelity simulation of chemical explosions and their interaction with solid particle clouds

NASA Astrophysics Data System (ADS)

Balakrishnan, Kaushik

The flow field behind chemical explosions in multiphase environments is investigated using a robust, state-of-the-art simulation strategy that accounts for the thermodynamics, gas dynamics and fluid mechanics of relevance to the problem. Focus is laid on the investigation of blast wave propagation, growth of hydrodynamic instabilities behind explosive blasts, the mixing aspects behind explosions, the effects of afterburn and its quantification, and the role played by solid particles in these phenomena. In particular, the confluence and interplay of these different physical phenomena are explored from a fundamental perspective, and applied to the problem of chemical explosions. A solid phase solver suited for the study of high-speed, two-phase flows has been developed and validated. This solver accounts for the inter-phase mass, momentum and energy transfer through empirical laws, and ensures two-way coupling between the two phases, viz. solid particles and gas. For dense flow fields, i.e., when the solid volume fraction becomes non-negligible (˜60%), the finite volume method with a Godunov type shock-capturing scheme requires modifications to account for volume fraction gradients during the computation of cell interface gas fluxes. To this end, the simulation methodology is extended with the formulation of an Eulerian gas, Lagrangian solid approach, thereby ensuring that the so developed two-phase simulation strategy can be applied for both flow conditions, dilute and dense alike. Moreover, under dense loading conditions the solid particles inevitably collide, which is accounted for in the current research effort with the use of an empirical collision/contact model from literature. Furthermore, the post-detonation flow field consists of gases under extreme temperature and pressure conditions, necessitating the use of real gas equations of state in the multiphase model. This overall simulation strategy is then extended to the investigation of chemical explosions in multiphase environments, with emphasis on the study of hydrodynamic instability growth, mixing, afterburn effects ensuing from the process, particle ignition and combustion (if reactive), dispersion, and their interaction with the vortices in the mixing layer. The post-detonation behavior of heterogeneous explosives is addressed by using three parts to the investigation. In the first part, only one-dimensional effects are considered, with the goal to assess the presently developed dense two-phase formulation. The total deliverable impulsive loading from heterogeneous explosive charges containing inert steel particles is estimated for a suite of operating parameters and compared, and it is demonstrated that heterogeneous explosive charges deliver a higher near-field impulse than homogeneous explosive charges containing the same mass of the high explosive. In the second part, three-dimensional effects such as hydrodynamic instabilities are accounted for, with the focus on characterizing the mixing layer ensuing from the detonation of heterogeneous explosive charges containing inert steel particles. It is shown that particles introduce significant amounts of hydrodynamic instabilities in the mixing layer, resulting in additional physical phenomena that play a prominent role in the flow features. In particular, the fluctuation intensities, fireball size and growth rates are augmented for heterogeneous explosions vis-a-vis homogeneous explosions, thereby demonstrating that solid particles enhance the perturbation intensities in the flow. In the third part of the investigation of heterogeneous explosions, dense, aluminized explosions are considered, and the particles are observed to burn in two phases, with an initial quenching due to the rarefaction wave, and a final quenching outside the fireball. Due to faster response time scales, smaller particles are observed to heat and accelerate more during early times, and also cool and decelerate more at late times, compared to counterpart larger particle sizes. Furthermore, the average particle velocities at late times are observed to be independent of the initial solid volume fraction in the explosive charge, as the particles eventually reach an equilibrium with the local gas. These studies have provided some crucial insights to the flow physics of dense, aluminized explosives. (Abstract shortened by UMI.)

Physics in ordered and disordered colloidal matter composed of poly(N-isopropylacrylamide) microgel particles.

PubMed

Yunker, Peter J; Chen, Ke; Gratale, Matthew D; Lohr, Matthew A; Still, Tim; Yodh, A G

2014-05-01

This review collects and describes experiments that employ colloidal suspensions to probe physics in ordered and disordered solids and related complex fluids. The unifying feature of this body of work is its clever usage of poly(N-isopropylacrylamide) (PNIPAM) microgel particles. These temperature-sensitive colloidal particles provide experimenters with a 'knob' for in situ control of particle size, particle interaction and particle packing fraction that, in turn, influence the structural and dynamical behavior of the complex fluids and solids. A brief summary of PNIPAM particle synthesis and properties is given, followed by a synopsis of current activity in the field. The latter discussion describes a variety of soft matter investigations including those that explore formation and melting of crystals and clusters, and those that probe structure, rearrangement and rheology of disordered (jammed/glassy) and partially ordered matter. The review, therefore, provides a snapshot of a broad range of physics phenomenology which benefits from the unique properties of responsive microgel particles.

Exposure Assessment for Atmospheric Ultrafine Particles (UFPs) and Implications in Epidemiologic Research

PubMed Central

Sioutas, Constantinos; Delfino, Ralph J.; Singh, Manisha

2005-01-01

Epidemiologic research has shown increases in adverse cardiovascular and respiratory outcomes in relation to mass concentrations of particulate matter (PM) ≤2.5 or ≤10 μm in diameter (PM2.5, PM10, respectively). In a companion article [Delfino RJ, Sioutas C, Malik S. 2005. Environ Health Perspect 113(8):934–946]), we discuss epidemiologic evidence pointing to underlying components linked to fossil fuel combustion. The causal components driving the PM associations remain to be identified, but emerging evidence on particle size and chemistry has led to some clues. There is sufficient reason to believe that ultrafine particles < 0.1 μm (UFPs) are important because when compared with larger particles, they have order of magnitudes higher particle number concentration and surface area, and larger concentrations of adsorbed or condensed toxic air pollutants (oxidant gases, organic compounds, transition metals) per unit mass. This is supported by evidence of significantly higher in vitro redox activity by UFPs than by larger PM. Although epidemiologic research is needed, exposure assessment issues for UFPs are complex and need to be considered before undertaking investigations of UFP health effects. These issues include high spatial variability, indoor sources, variable infiltration of UFPs from a variety of outside sources, and meteorologic factors leading to high seasonal variability in concentration and composition, including volatility. To address these issues, investigators need to develop as well as validate the analytic technologies required to characterize the physical/chemical nature of UFPs in various environments. In the present review, we provide a detailed discussion of key characteristics of UFPs, their sources and formation mechanisms, and methodologic approaches to assessing population exposures. PMID:16079062

Occurrence and Characteristics of {sup 18}O-exchange Reactions Catalyzed By Sodium- and Potassium-dependent Adenosine Triphosphatases

DOE R&D Accomplishments Database

Dahms, A. S.; Boyer, P. D.

This discusses the following topics in High Energy Physics: The Particle Zoo; The Strong and the Weak; The Particle Explosion; Deep Inside the Nucleon; The Search for Unity; Physics in Collision; The Standard Model; Particles and the Cosmos; and Practical Benefits.

The contribution of Medical Physics to Nuclear Medicine: looking back - a physicist's perspective.

PubMed

Hutton, Brian F

2014-12-01

This paper is the first in a series of invited perspectives by four pioneers of Nuclear Medicine imaging and physics. A medical physicist and a Nuclear Medicine clinical specialist each take a backward look and a forward look at the contributions of Medical Physics to Nuclear Medicine. Contributions of Medical Physics are presented from the early discovery of radioactivity, development of first imaging devices, computers and emission tomography to recent development of hybrid imaging. There is evidence of significant contribution of Medical Physics throughout the development of Nuclear Medicine.

A Hybrid Physics-Based Data-Driven Approach for Point-Particle Force Modeling

NASA Astrophysics Data System (ADS)

Moore, Chandler; Akiki, Georges; Balachandar, S.

2017-11-01

This study improves upon the physics-based pairwise interaction extended point-particle (PIEP) model. The PIEP model leverages a physical framework to predict fluid mediated interactions between solid particles. While the PIEP model is a powerful tool, its pairwise assumption leads to increased error in flows with high particle volume fractions. To reduce this error, a regression algorithm is used to model the differences between the current PIEP model's predictions and the results of direct numerical simulations (DNS) for an array of monodisperse solid particles subjected to various flow conditions. The resulting statistical model and the physical PIEP model are superimposed to construct a hybrid, physics-based data-driven PIEP model. It must be noted that the performance of a pure data-driven approach without the model-form provided by the physical PIEP model is substantially inferior. The hybrid model's predictive capabilities are analyzed using more DNS. In every case tested, the hybrid PIEP model's prediction are more accurate than those of physical PIEP model. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1315138 and the U.S. DOE, NNSA, ASC Program, as a Cooperative Agreement under Contract No. DE-NA0002378.

Particle Dark Matter constraints: the effect of Galactic uncertainties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benito, Maria; Bernal, Nicolás; Iocco, Fabio

2017-02-01

Collider, space, and Earth based experiments are now able to probe several extensions of the Standard Model of particle physics which provide viable dark matter candidates. Direct and indirect dark matter searches rely on inputs of astrophysical nature, such as the local dark matter density or the shape of the dark matter density profile in the target in object. The determination of these quantities is highly affected by astrophysical uncertainties. The latter, especially those for our own Galaxy, are ill-known, and often not fully accounted for when analyzing the phenomenology of particle physics models. In this paper we present amore » systematic, quantitative estimate of how astrophysical uncertainties on Galactic quantities (such as the local galactocentric distance, circular velocity, or the morphology of the stellar disk and bulge) propagate to the determination of the phenomenology of particle physics models, thus eventually affecting the determination of new physics parameters. We present results in the context of two specific extensions of the Standard Model (the Singlet Scalar and the Inert Doublet) that we adopt as case studies for their simplicity in illustrating the magnitude and impact of such uncertainties on the parameter space of the particle physics model itself. Our findings point toward very relevant effects of current Galactic uncertainties on the determination of particle physics parameters, and urge a systematic estimate of such uncertainties in more complex scenarios, in order to achieve constraints on the determination of new physics that realistically include all known uncertainties.« less

Measurement and Modeling of Electromagnetic Scattering by Particles and Particle Groups. Chapter 3

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.

2015-01-01

Small particles forming clouds of interstellar and circumstellar dust, regolith surfaces of many solar system bodies, and cometary atmospheres have a strong and often controlling effect on many ambient physical and chemical processes. Similarly, aerosol and cloud particles exert a strong influence on the regional and global climates of the Earth, other planets of the solar system, and exoplanets. Therefore, detailed and accurate knowledge of physical and chemical characteristics of such particles has the utmost scientific importance.

Quantum Optics, Diffraction Theory, and Elementary Particle Physics

ScienceCinema

Glauber, Roy

2018-05-22

Physical optics has expanded greatly in recent years. Though it remains part of the ancestry of elementary particle physics, there are once again lessons to be learned from it. I shall discuss several of these, including some that have emerged at CERN and Brookhaven.

Perspective Space as a Model for Distance and Size Perception.

PubMed

Erkelens, Casper J

2017-01-01

In the literature, perspective space has been introduced as a model of visual space. Perspective space is grounded on the perspective nature of visual space during both binocular and monocular vision. A single parameter, that is, the distance of the vanishing point, transforms the geometry of physical space into that of perspective space. The perspective-space model predicts perceived angles, distances, and sizes. The model is compared with other models for distance and size perception. Perspective space predicts that perceived distance and size as a function of physical distance are described by hyperbolic functions. Alternatively, power functions have been widely used to describe perceived distance and size. Comparison of power and hyperbolic functions shows that both functions are equivalent within the range of distances that have been judged in experiments. Two models describing perceived distance on the ground plane appear to be equivalent with the perspective-space model too. The conclusion is that perspective space unifies a number of models of distance and size perception.

Perspective Space as a Model for Distance and Size Perception

PubMed Central

2017-01-01

In the literature, perspective space has been introduced as a model of visual space. Perspective space is grounded on the perspective nature of visual space during both binocular and monocular vision. A single parameter, that is, the distance of the vanishing point, transforms the geometry of physical space into that of perspective space. The perspective-space model predicts perceived angles, distances, and sizes. The model is compared with other models for distance and size perception. Perspective space predicts that perceived distance and size as a function of physical distance are described by hyperbolic functions. Alternatively, power functions have been widely used to describe perceived distance and size. Comparison of power and hyperbolic functions shows that both functions are equivalent within the range of distances that have been judged in experiments. Two models describing perceived distance on the ground plane appear to be equivalent with the perspective-space model too. The conclusion is that perspective space unifies a number of models of distance and size perception. PMID:29225765

Toward a unifying constitutive relation for sediment transport across environments

NASA Astrophysics Data System (ADS)

Houssais, Morgane; Jerolmack, Douglas J.

2017-01-01

Landscape evolution models typically parse the environment into different process domains, each with its own sediment transport law: e.g., soil creep, landslides and debris flows, and river bed-load and suspended-sediment transport. Sediment transport in all environments, however, contains many of the same physical ingredients, albeit in varying proportions: grain entrainment due to a shear force, that is a combination of fluid flow, particle-particle friction and gravity. We present a new take on the perspective originally advanced by Bagnold, that views the long profile of a hillsope-river-shelf system as a continuous gradient of decreasing granular friction dominance and increasing fluid drag dominance on transport capacity. Recent advances in understanding the behavior and regime transitions of dense granular systems suggest that the entire span of granular-to-fluid regimes may be accommodated by a single-phase rheology. This model predicts a material-flow effective friction (or viscosity) that changes with the degree of shear rate and confining pressure. We present experimental results confirming that fluid-driven sediment transport follows this same rheology, for bed and suspended load. Surprisingly, below the apparent threshold of motion we observe that sediment particles creep, in a manner characteristic of glassy systems. We argue that this mechanism is relevant for both hillslopes and rivers. We discuss the possibilities of unifying sediment transport across environments and disciplines, and the potential consequences for modeling landscape evolution.

Measurement realities of current collection in dynamic space plasma environments

NASA Technical Reports Server (NTRS)

Szuszczewicz, Edward P.

1990-01-01

Theories which describe currents collected by conducting and non-conducting bodies immersed in plasmas have many of their concepts based upon the fundamentals of sheath-potential distributions and charged-particle behavior in superimposed electric and magnetic fields. Those current-collecting bodies (or electrodes) may be Langmuir probes, electric field detectors, aperture plates on ion mass spectrometers and retarding potential analyzers, or spacecraft and their rigid and tethered appendages. Often the models are incomplete in representing the conditions under which the current-voltage characteristics of the electrode and its system are to be measured. In such cases, the experimenter must carefully take into account magnetic field effects and particle anisotropies, perturbations caused by the current collection process itself and contamination on electrode surfaces, the complexities of non-Maxwellian plasma distributions, and the temporal variability of the local plasma density, temperature, composition and fields. This set of variables is by no means all-inclusive, but it represents a collection of circumstances guaranteed to accompany experiments involving energetic particle beams, plasma discharges, chemical releases, wave injection and various events of controlled and uncontrolled spacecraft charging. Here, an attempt is made to synopsize these diagnostic challenges and frame them within a perspective that focuses on the physics under investigation and the requirements on the parameters to be measured. Examples include laboratory and spaceborne applications, with specific interest in dynamic and unstable plasma environments.

Elementary particle physics

NASA Technical Reports Server (NTRS)

Perkins, D. H.

1986-01-01

Elementary particle physics is discussed. Status of the Standard Model of electroweak and strong interactions; phenomena beyond the Standard Model; new accelerator projects; and possible contributions from non-accelerator experiments are examined.

A proposed physical analog for a quantum probability amplitude

NASA Astrophysics Data System (ADS)

Boyd, Jeffrey

What is the physical analog of a probability amplitude? All quantum mathematics, including quantum information, is built on amplitudes. Every other science uses probabilities; QM alone uses their square root. Why? This question has been asked for a century, but no one previously has proposed an answer. We will present cylindrical helices moving toward a particle source, which particles follow backwards. Consider Feynman's book QED. He speaks of amplitudes moving through space like the hand of a spinning clock. His hand is a complex vector. It traces a cylindrical helix in Cartesian space. The Theory of Elementary Waves changes direction so Feynman's clock faces move toward the particle source. Particles follow amplitudes (quantum waves) backwards. This contradicts wave particle duality. We will present empirical evidence that wave particle duality is wrong about the direction of particles versus waves. This involves a paradigm shift; which are always controversial. We believe that our model is the ONLY proposal ever made for the physical foundations of probability amplitudes. We will show that our ``probability amplitudes'' in physical nature form a Hilbert vector space with adjoints, an inner product and support both linear algebra and Dirac notation.

HIGH ENERGY PHYSICS: CERN Link Breathes Life Into Russian Physics.

PubMed

Stone, R

2000-10-13

Without fanfare, 600 Russian scientists here at CERN, the European particle physics laboratory, are playing key roles in building the Large Hadron Collider (LHC), a machine that will explore fundamental questions such as why particles have mass, as well as search for exotic new particles whose existence would confirm supersymmetry, a popular theory that aims to unify the four forces of nature. In fact, even though Russia is not one of CERN's 20 member states, most top high-energy physicists in Russia are working on the LHC. Some say their work could prove the salvation of high-energy physics back home.

News Teaching: The epiSTEMe project: KS3 maths and science improvement Field trip: Pupils learn physics in a stately home Conference: ShowPhysics welcomes fun in Europe Student numbers: Physics numbers increase in UK Tournament: Physics tournament travels to Singapore Particle physics: Hadron Collider sets new record Astronomy: Take your classroom into space Forthcoming Events

NASA Astrophysics Data System (ADS)

2010-05-01

Teaching: The epiSTEMe project: KS3 maths and science improvement Field trip: Pupils learn physics in a stately home Conference: ShowPhysics welcomes fun in Europe Student numbers: Physics numbers increase in UK Tournament: Physics tournament travels to Singapore Particle physics: Hadron Collider sets new record Astronomy: Take your classroom into space Forthcoming Events

Fact Sheets and Brochures | News

Science.gov Websites

Illinois Accelerator Research Center Economic Impact Particle Physics: Benefits to Society The Fermilab Saturday Morning Physics What are neutrinos? What are neutrinos? (large format) What is a Higgs boson? U.S Public Outreach America's particle physics and accelerator laboratory LBNF/DUNE - An international mega

THE SMALL VOLUME PARTICLE MICROSAMPLER (SVPM): A NEW APPROACH TO PARTICLE SIZE DISTRIBUTION AND COMPOSITION. (R827090)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Macroscopic to Microscopic Scales of Particulate Dosimetry: From Source to Fate in the Body

EPA Science Inventory

Additional perspective with regards to particle dosimetry is achieved by exploring dosimetry across a range of scales from macroscopic to microscopic in scope. Typically, one thinks of dosimetry as what happens when a particle is inhaled, where it is deposited, and how it is clea...

LUNG INFLAMMATION INDUCED BY CONCENTRATED AMBIENT AIR PARTICLES IS RELATED TO PARTICLE COMPOSITION. (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Design Considerations for High Energy Electron -- Positron Storage Rings

DOE R&D Accomplishments Database

Richter, B.

1966-11-01

High energy electron-positron storage rings give a way of making a new attack on the most important problems of elementary particle physics. All of us who have worked in the storage ring field designing, building, or using storage rings know this. The importance of that part of storage ring work concerning tests of quantum electrodynamics and mu meson physics is also generally appreciated by the larger physics community. However, I do not think that most of the physicists working tin the elementary particle physics field realize the importance of the contribution that storage ring experiments can make to our understanding of the strongly interacting particles. I would therefore like to spend the next few minutes discussing the sort of things that one can do with storage rings in the strongly interacting particle field.

Particle Detectors

NASA Astrophysics Data System (ADS)

Grupen, Claus; Shwartz, Boris

2011-09-01

Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

Belle2VR: A Virtual-Reality Visualization of Subatomic Particle Physics in the Belle II Experiment.

PubMed

Duer, Zach; Piilonen, Leo; Glasson, George

2018-05-01

Belle2VR is an interactive virtual-reality visualization of subatomic particle physics, designed by an interdisciplinary team as an educational tool for learning about and exploring subatomic particle collisions. This article describes the tool, discusses visualization design decisions, and outlines our process for collaborative development.

Lithium Gadolinium Borate in Plastic Scintillator as an Antineutrino Detection Material

DTIC Science & Technology

2010-06-01

advancement of fundamental particle physics, development of the standard model of particle physics and our understanding many cosmological processes...MeVee). Where the light produced by by a 1MeV electron is 1 MeVee by definition , but a heavy charged particle would have a kinetic energy of several

Teaching Particle Physics in the Open University's Science Foundation Course.

ERIC Educational Resources Information Center

Farmelo, Graham

1992-01-01

Discusses four topics presented in the science foundation course of the Open University that exemplify current developments in particle physics, in particular, and that describe important issues about the nature of science, in general. Topics include the omega minus particle, the diversity of quarks, the heavy lepton, and the discovery of the W…

Future particle-physics projects in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denisov, D. S., E-mail: denisovd@fnal.gov

2015-07-15

Basic proposals of experiments aimed at precision measurements of Standard Model parameters and at searches for new particles, including dark-matter particles, are described along with future experimental projects considered by American Physical Society at the meeting in the summer of 2013 and intended for implementation within the next ten to twenty years.

Future particle-physics projects in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denisov, D. S.

2015-08-25

Basic proposals of experiments aimed at precision measurements of Standard Model parameters and at searches for new particles, including dark-matter particles, are described along with future experimental projects considered by American Physical Society at the meeting in the summer of 2013 and intended for implementation within the next ten to twenty years.

Semiconductor devices for entangled photon pair generation: a review

NASA Astrophysics Data System (ADS)

Orieux, Adeline; Versteegh, Marijn A. M.; Jöns, Klaus D.; Ducci, Sara

2017-07-01

Entanglement is one of the most fascinating properties of quantum mechanical systems; when two particles are entangled the measurement of the properties of one of the two allows the properties of the other to be instantaneously known, whatever the distance separating them. In parallel with fundamental research on the foundations of quantum mechanics performed on complex experimental set-ups, we assist today with bourgeoning of quantum information technologies bound to exploit entanglement for a large variety of applications such as secure communications, metrology and computation. Among the different physical systems under investigation, those involving photonic components are likely to play a central role and in this context semiconductor materials exhibit a huge potential in terms of integration of several quantum components in miniature chips. In this article we review the recent progress in the development of semiconductor devices emitting entangled photons. We will present the physical processes allowing the generation of entanglement and the tools to characterize it; we will give an overview of major recent results of the last few years and highlight perspectives for future developments.

Topology, localization, and quantum information in atomic, molecular and optical systems

NASA Astrophysics Data System (ADS)

Yao, Norman Ying

The scientific interface between atomic, molecular and optical (AMO) physics, condensed matter, and quantum information science has recently led to the development of new insights and tools that bridge the gap between macroscopic quantum behavior and detailed microscopic intuition. While the dialogue between these fields has sharpened our understanding of quantum theory, it has also raised a bevy of new questions regarding the out-of-equilibrium dynamics and control of many-body systems. This thesis is motivated by experimental advances that make it possible to produce and probe isolated, strongly interacting ensembles of disordered particles, as found in systems ranging from trapped ions and Rydberg atoms to ultracold polar molecules and spin defects in the solid state. The presence of strong interactions in these systems underlies their potential for exploring correlated many-body physics and this thesis presents recent results on realizing fractionalization and localization. From a complementary perspective, the controlled manipulation of individual quanta can also enable the bottom-up construction of quantum devices. To this end, this thesis also describes blueprints for a room-temperature quantum computer, quantum credit cards and nanoscale quantum thermometry.

Space-time development of electromagnetic and hadronic showers and perspectives for novel calorimetric techniques

DOE PAGES

Benaglia, Andrea; Auffray, Etiennette; Lecoq, Paul; ...

2016-04-20

The performance of hadronic calorimeters will be a key parameter at the next generation of High Energy Physics accelerators. A detector combining fine granularity with excellent timing information would prove beneficial for the reconstruction of both jets and electromagnetic particles with high energy resolution. In this work, the space and time structure of high energy showers is studied by means of a Geant4-based simulation toolkit. In particular, the relevant time scales of the different physics phenomena contributing to the energy loss are investigated. A correlation between the fluctuations of the energy deposition of high energy hadrons and the time developmentmore » of the showers is observed, which allows for an event-by-event correction to be computed to improve the energy resolution of the calorimeter. Lastly, these studies are intended to set the basic requirements for the development of a new-concept, total absorption time-imaging calorimeter, which seems now within reach thanks to major technological advancements in the production of fast scintillating materials and compact photodetectors.« less

Nuclear Science and Applications with the Next Generation of High-Power Lasers and Brilliant Low-Energy Gamma Beams at ELI-NP

NASA Astrophysics Data System (ADS)

Gales, S.

The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular Particle and Nuclear Physics, Astrophysics as well as societal applications in Material Science, Nuclear Energy and Medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called "ELI" for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW lasers and a Compton back-scattering high-brilliance and intense low-energy gamma beam, a marriage of laser and accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed.

Comprehensive model for predicting elemental composition of coal pyrolysis products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ricahrds, Andrew P.; Shutt, Tim; Fletcher, Thomas H.

Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumptionmore » is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases.« less

Learning about a Level Physics Students' Understandings of Particle Physics Using Concept Mapping

ERIC Educational Resources Information Center

Gourlay, H.

2017-01-01

This paper describes a small-scale piece of research using concept mapping to elicit A level students' understandings of particle physics. Fifty-nine year 12 (16- and 17 year-old) students from two London schools participated. The exercise took place during school physics lessons. Students were instructed how to make a concept map and were…

Plasmonic particles of colloidal silver in high-resolution recording media

NASA Astrophysics Data System (ADS)

Andreeva, O. V.; Andreeva, N. V.; Kuzmina, T. B.

2017-01-01

The optical properties of colloidal silver particles formed photographically in high-resolution silver halide photographic materials have been considered. The conditions that allow one to obtain exposed and developed light-sensitive silver halide particles in the form of colloidal particles of metallic silver having the properties of localized plasmons have been described. The results of the studies of the developed silver particles in traditional photographic materials for image holography and in nanoporous silver halide photographic materials for volume holography have been presented. The perspectives of using plasmonic silver nanoparticles produced photographically have been discussed.

Physical Activity Promotion in Call Centres: Employers' Perspectives

ERIC Educational Resources Information Center

Renton, Sheila J.; Lightfoot, Nancy E.; Maar, Marion A.

2011-01-01

This study followed a predominantly qualitative approach to explore the perspectives of employers in Sudbury, Ontario, Canada, call centres (CCs) regarding physical activity (PA) promotion in workplaces, by identifying current practices and employers' motivation to promote PA, as well as perceived facilitators and barriers. In-depth interviews…

Student Perspectives of Grading in Physical Education

ERIC Educational Resources Information Center

Zhu, Xihe

2015-01-01

Recent state and federal legislations on educational accountability push evaluation and grading to the frontline. This study examined students' perspectives of grading in physical education. The participants included students (N = 39) from two middle schools. Data were collected through observation, student profile grading sheets and interviews.…

Particle transport and deposition: basic physics of particle kinetics

PubMed Central

Tsuda, Akira; Henry, Frank S.; Butler, James P.

2015-01-01

The human body interacts with the environment in many different ways. The lungs interact with the external environment through breathing. The enormously large surface area of the lung with its extremely thin air-blood barrier is exposed to particles suspended in the inhaled air. Whereas the particle-lung interaction may cause deleterious effects on health if the inhaled pollutant aerosols are toxic, this interaction can be beneficial for disease treatment if the inhaled particles are therapeutic aerosolized drug. In either case, an accurate estimation of dose and sites of deposition in the respiratory tract is fundamental to understanding subsequent biological response, and the basic physics of particle motion and engineering knowledge needed to understand these subjects is the topic of this chapter. A large portion of this chapter deals with three fundamental areas necessary to the understanding of particle transport and deposition in the respiratory tract. These are: 1) the physical characteristics of particles, 2) particle behavior in gas flow, and 3) gas flow patterns in the respiratory tract. Other areas, such as particle transport in the developing lung and in the diseased lung are also considered. The chapter concludes with a summary and a brief discussion of areas of future research. PMID:24265235

Scientific program and abstracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerich, C.

1983-01-01

The Fifth International Conference on High-Power Particle Beams is organized jointly by the Lawrence Livermore National Laboratory and Physics International Company. As in the previous conferences in this series, the program includes the following topics: high-power, electron- and ion-beam acceleration and transport; diode physics; high-power particle beam interaction with plasmas and dense targets; particle beam fusion (inertial confinement); collective ion acceleration; particle beam heating of magnetically confined plasmas; and generation of microwave/free-electron lasers.

The Learning Reconstruction of Particle System and Linear Momentum Conservation in Introductory Physics Course

NASA Astrophysics Data System (ADS)

Karim, S.; Saepuzaman, D.; Sriyansyah, S. P.

2016-08-01

This study is initiated by low achievement of prospective teachers in understanding concepts in introductory physics course. In this case, a problem has been identified that students cannot develop their thinking skills required for building physics concepts. Therefore, this study will reconstruct a learning process, emphasizing a physics concept building. The outcome will design physics lesson plans for the concepts of particle system as well as linear momentum conservation. A descriptive analysis method will be used in order to investigate the process of learning reconstruction carried out by students. In this process, the students’ conceptual understanding will be evaluated using essay tests for concepts of particle system and linear momentum conservation. The result shows that the learning reconstruction has successfully supported the students’ understanding of physics concept.

Statistical Physics Experiments Using Dusty Plasmas

NASA Astrophysics Data System (ADS)

Goree, John

2016-10-01

Compared to other areas of physics research, Statistical Physics is heavily dominated by theory, with comparatively little experiment. One reason for the lack of experiments is the impracticality of tracking of individual atoms and molecules within a substance. Thus, there is a need for a different kind of experimental system, one where individual particles not only move stochastically as they collide with one another, but also are large enough to allow tracking. A dusty plasma can meet this need. A dusty plasma is a partially ionized gas containing small particles of solid matter. These micron-size particles gain thousands of electronic charges by collecting more electrons than ions. Their motions are dominated by Coulomb collisions with neighboring particles. In this so-called strongly coupled plasma, the dust particles self-organize in much the same way as atoms in a liquid or solid. Unlike atoms, however, these particles are large and slow, so that they can be tracked easily by video microscopy. Advantages of dusty plasma for experimental statistical physics research include particle tracking, lack of frictional contact with solid surfaces, and avoidance of overdamped motion. Moreover, the motion of a collection of dust particles can mimic an equilibrium system with a Maxwellian velocity distribution, even though the dust particles themselves are not truly in thermal equilibrium. Nonequilibrium statistical physics can be studied by applying gradients, for example by imposing a shear flow. In this talk I will review some of our recent experiments with shear flow. First, we performed the first experimental test to verify the Fluctuation Theorem for a shear flow, showing that brief violations of the Second Law of Thermodynamics occur with the predicted probabilities, for a small system. Second, we discovered a skewness of a shear-stress distribution in a shear flow. This skewness is a phenomenon that likely has wide applicability in nonequilibrium steady states. Third, we performed the first experimental test of a statistical physics theory (the Green-Kubo model) that is widely used by physical chemists to compute viscosity coefficients, and we found that it fails. Work supported by the U.S. Department of Energy, NSF, and NASA.

PEOPLE IN PHYSICS: Interview with Peter Higgs

NASA Astrophysics Data System (ADS)

Fancey, Conducted by Norman

1998-01-01

Peter Higgs, FRSE, FRS held until recently a personal chair in theoretical physics at the University of Edinburgh and is now an emeritus professor. Peter is well known for predicting the existence of a new particle, the Higgs boson - as yet unconfirmed. He has been awarded a number of prizes in recognition of his work, most recently the Paul Dirac Medal and Prize for outstanding contributions to theoretical physics from the Institute of Physics and the 1997 High Energy and Particle Physics Prize by the European Physical Society.

Defining Adapted Physical Activity: International Perspectives

ERIC Educational Resources Information Center

Hutzler, Yeshayahu; Sherrill, Claudine

2007-01-01

The purpose of this study was to describe international perspectives concerning terms, definitions, and meanings of adapted physical activity (APA) as (a) activities or service delivery, (b) a profession, and (c) an academic field of study. Gergen's social constructionism, our theory, guided analysis of multiple sources of data via qualitative…

Students' Perspectives of Urban Middle School Physical Education Programs

ERIC Educational Resources Information Center

Dyson, Ben; Coviello, Nicole; DiCesare, Emma; Dyson, Lisa

2009-01-01

The purpose of this study was to explore and interpret students' perspectives of their experiences in four urban middle school physical education programs. Focus group interviews with 76 students were supported by field notes and researchers' reflective journals. Researchers used constant comparison methods (Lincoln & Guba, 1985) to identify seven…

Flute Physics from a Flutist's Perspective

ERIC Educational Resources Information Center

Boysen, Erika; Ruiz, Michael J.

2017-01-01

The basic physics of the flute is presented from the perspective of a professional flutist. The flutist can control loudness, pitch and to some extent timbre. Oscilloscope images are provided to compare changes in these three fundamental sound characteristics. Readers can view a video (Ruiz 2017 "Video: The Flute"…

Adolescents' Perspectives on the Barriers and Facilitators of Physical Activity: A Systematic Review of Qualitative Studies

ERIC Educational Resources Information Center

Martins, João; Marques, Adilson; Sarmento, Hugo; Carreiro da Costa, Francisco

2015-01-01

This article examined qualitative studies of adolescents' perspectives about the facilitators and barriers of physical activity, published from 2007 to 2014. A systematic review of "Web of Science", "EBSCO", "Psychinfo" and "ERIC" databases was performed according to Preferred Reporting Items for Systematic…

Examining South Korea's Elementary Physical Education Performance Assessment Using Assessment Literacy Perspectives

ERIC Educational Resources Information Center

Park, Yongnam

2017-01-01

This study examines the issues pertaining to South Korea's elementary physical education (PE) performance assessment, using an assessment literacy (Hay & Penney, 2013) perspective to propose future directions. Eight elementary teachers currently teaching PE were selected as participants. Data were collected through semi-structured in-depth…

Physical Activity at Daycare: Issues, Challenges and Perspectives

ERIC Educational Resources Information Center

van Zandvoort, Melissa; Tucker, Patricia; Irwin, Jennifer D.; Burke, Shauna M.

2010-01-01

This study sought to examine London, Ontario-based childcare providers' perspectives of the barriers and facilitators to physical activity participation among preschoolers (i.e. children aged 2.5-5 years) attending daycare. A heterogeneous sample of childcare providers (n = 54; response rate 47%) working at public daycare facilities in London,…

A question of balance: Explaining differences between parental and grandparental perspectives on preschoolers' feeding and physical activity.

PubMed

Eli, Karin; Howell, Kyndal; Fisher, Philip A; Nowicka, Paulina

2016-04-01

Although one quarter of US and UK families rely on grandparents as the main providers of informal childcare, grandparental perspectives on the feeding and physical activity of young children remain understudied. The study's aim was to elucidate parents' and grandparents' perspectives on young children's feeding and physical activity, and identify how they negotiate potential differences between these perspectives. We interviewed 22 parents and 27 grandparents from 16 families of children aged 3-5 years in the Pacific Northwest, US. Using familial homeostasis as a novel theoretical framework, the interviews were analyzed to assess differences between parental and grandparental perspectives on feeding and physical activity. The analysis yielded six thematic categories: (1) disagreements about feeding stem from parents' and grandparents' differing definitions of healthy feeding; (2) differences between parents' and grandparents' feeding practices reflect differences in perceived caretaking roles; (3) parents and grandparents negotiate differences in feeding practices through grandparental compliance and parental compromise; (4) differences in preschoolers' physical activity are influenced by parents' and grandparents' own access to and engagement in physical activity; (5) parents and grandparents express few disagreements about preschoolers' screen-time; (6) parents and grandparents rarely discuss preschoolers' physical activity. The findings suggest that parental and grandparental decision-making about feeding and exercise is informed by ideas of what constitutes familial balance and a balanced lifestyle for a preschool aged child, rather than by the child's weight status. Parents and grandparents appear to engage in practices designed to preserve familial homeostasis, which may provide a compelling explanation for the persistent difficulties in implementing family-based childhood obesity interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

A question of balance: Explaining differences between parental and grandparental perspectives on preschoolers' feeding and physical activity

PubMed Central

Eli, Karin; Howell, Kyndal; Fisher, Philip A.; Nowicka, Paulina

2017-01-01

Rationale Although one quarter of US and UK families rely on grandparents as the main providers of informal childcare, grandparental perspectives on the feeding and physical activity of young children remain understudied. Objective The study's aim was to elucidate parents' and grandparents' perspectives on young children's feeding and physical activity, and identify how they negotiate potential differences between these perspectives. Methods We interviewed 22 parents and 27 grandparents from 16 families of children aged 3–5 years in the Pacific Northwest, US. Using familial homeostasis as a novel theoretical framework, the interviews were analyzed to assess differences between parental and grandparental perspectives on feeding and physical activity. Results The analysis yielded six thematic categories: (1) disagreements about feeding stem from parents' and grandparents' differing definitions of healthy feeding; (2) differences between parents' and grandparents' feeding practices reflect differences in perceived caretaking roles; (3) parents and grandparents negotiate differences in feeding practices through grandparental compliance and parental compromise; (4) differences in preschoolers' physical activity are influenced by parents' and grandparents' own access to and engagement in physical activity; (5) parents and grandparents express few disagreements about preschoolers' screen-time; (6) parents and grandparents rarely discuss preschoolers' physical activity. The findings suggest that parental and grandparental decision-making about feeding and exercise is informed by ideas of what constitutes familial balance and a balanced lifestyle for a preschool aged child, rather than by the child's weight status. Conclusions Parents and grandparents appear to engage in practices designed to preserve familial homeostasis, which may provide a compelling explanation for the persistent difficulties in implementing family-based childhood obesity interventions. PMID:26943011

An Integrated Higgs Force Theory

NASA Astrophysics Data System (ADS)

Colella, Antonio

2016-03-01

An Integrated Higgs force theory (IHFT) was based on 2 key requirement amplifications: a matter particle/Higgs force was one and inseparable; a matter particle/Higgs force bidirectionally condensed/evaporated from/to super force. These were basis of 5 theories: particle creation, baryogenesis, superpartner/quark decays, spontaneous symmetry breaking, and stellar black holes. Our universe's 129 matter/force particles contained 64 supersymmetric Higgs particles; 9 transient matter particles/Higgs forces decayed to 8 permanent matter particles/Higgs forces; mass was given to a matter particle by its Higgs force and gravitons; and sum of 8 Higgs force energies of 8 permanent matter particles was dark energy. An IHFT's essence is the intimate physical relationships between 8 theories. These theories are independent because physicists in one theory worked independently of physicists in the other seven. An IHFT's premise is without sacrificing their integrities, 8 independent existing theories are replaced by 8 interrelated amplified theories. Requirement amplifications provide interfaces between the 8 theories. Intimate relationships between 8 theories including the above 5 and string, Higgs forces, and Super Universe are described. The sorting category selected was F. PARTICLES AND FIELDS (e.g., F1 Higgs Physics, F10 Alternative Beyond the Standard Model Physics, F11 Dark Sector Theories and Searches, and F12 Particle Cosmology).

National Study of Excellence and Innovation in Physical Therapist Education: Part 2-A Call to Reform.

PubMed

Jensen, Gail M; Hack, Laurita M; Nordstrom, Terrence; Gwyer, Janet; Mostrom, Elizabeth

2017-09-01

This perspective shares recommendations that draw from (1) the National Study of Excellence and Innovation in Physical Therapist Education research findings and a conceptual model of excellence in physical therapist education, (2) the Carnegie Foundation's Preparation for the Professions Program (PPP), and (3) research in the learning sciences. The 30 recommendations are linked to the dimensions described in the conceptual model for excellence in physical therapist education: Culture of Excellence, Praxis of Learning, and Organizational Structures and Resources. This perspective proposes a transformative call for reform framed across 3 core categories: (1) creating a culture of excellence, leadership, and partnership, (2) advancing the learning sciences and understanding and enacting the social contract, and (3) implementing organizational imperatives. Similar to the Carnegie studies, this perspective identifies action items (9) that should be initiated immediately in a strategic and systematic way by the major organizational stakeholders in physical therapist education. These recommendations and action items provide a transformative agenda for physical therapist education, and thus the profession, in meeting the changing needs of society through higher levels of excellence. © 2017 American Physical Therapy Association.

Fermilab | About Fermilab | Photo and Video Gallery

Science.gov Websites

LHC Dark matter and dark energy ADMX Muons More fundamental particles and forces Theory Scientific society Particle Physics 101 Science of matter, energy, space and time How particle physics discovery rarely interact with matter. thumb Med-Res Hi-Res A view of Fermilab's MINERvA detector with the MINOS

Meta-Analysis inside and outside Particle Physics: Two Traditions That Should Converge?

ERIC Educational Resources Information Center

Baker, Rose D.; Jackson, Dan

2013-01-01

The use of meta-analysis in medicine and epidemiology really took off in the 1970s. However, in high-energy physics, the Particle Data Group has been carrying out meta-analyses of measurements of particle masses and other properties since 1957. Curiously, there has been virtually no interaction between those working inside and outside particle…

Biofeedback in Partial Weight Bearing: Usability of Two Different Devices from a Patient’s and Physical Therapist’s Perspective

PubMed Central

van Lieshout, Remko; Pisters, Martijn F.; Vanwanseele, Benedicte; de Bie, Rob A.; Wouters, Eveline J.; Stukstette, Mirelle J.

2016-01-01

Background Partial weight bearing is frequently instructed by physical therapists in patients after lower-limb trauma or surgery. The use of biofeedback devices seems promising to improve the patient’s compliance with weight-bearing instructions. SmartStep and OpenGo-Science are biofeedback devices that provide real-time feedback. For a successful implementation, usability of the devices is a critical aspect and should be tested from a user’s perspective. Aim To describe the usability from the physical therapists’ and a patients’ perspective of Smartstep and OpenGo-Science to provide feedback on partial weight bearing during supervised rehabilitation of patients after lower-limb trauma or surgery. Methods In a convergent mixed-methods design, qualitative and quantitative data were collected. Usability was subdivided into user performance, satisfaction and acceptability. Patients prescribed with partial weight bearing and their physical therapists were asked to use SmartStep and OpenGo-Science during supervised rehabilitation. Usability was qualitatively tested by a think-aloud method and a semi-structured interview and quantitatively tested by the System-Usability-Scale (SUS) and closed questions. For the qualitative data thematic content analyses were used. Results Nine pairs of physical therapists and their patients participated. The mean SUS scores for patients and physical therapists were for SmartStep 70 and 53, and for OpenGo-Science 79 and 81, respectively. Scores were interpreted with the Curved Grading Scale. The qualitative data showed that there were mixed views and perceptions from patients and physical therapists on satisfaction and acceptability. Conclusion This study gives insight in the usability of two biofeedback devices from the patient’s and physical therapist’s perspective. The overall usability from both perspectives seemed to be acceptable for OpenGo-Science. For SmartStep, overall usability seemed only acceptable from the patient’s perspective. Implication The study findings could help clinicians to decide which biofeedback device is appropriate for their given situation and provide information for future development of biofeedback devices. PMID:27798674

Irreducible Brillouin conditions and contracted Schrödinger equations for n-electron systems. III. Systems of noninteracting electrons.

PubMed

Kutzelnigg, Werner; Mukherjee, Debashis

2004-04-22

We analyze the structure and the solutions of the irreducible k-particle Brillouin conditions (IBCk) and the irreducible contracted Schrödinger equations (ICSEk) for an n-electron system without electron interaction. This exercise is very instructive in that it gives one both the perspective and the strategies to be followed in applying the IBC and ICSE to physically realistic systems with electron interaction. The IBC1 leads to a Liouville equation for the one-particle density matrix gamma1=gamma, consistent with our earlier analysis that the IBC1 holds both for a pure and an ensemble state. The IBC1 or the ICSE1 must be solved subject to the constraints imposed by the n-representability condition, which is particularly simple for gamma. For a closed-shell state gamma is idempotent, i.e., all natural spin orbitals (NSO's) have occupation numbers 0 or 1, and all cumulants lambdak with k> or =2 vanish. For open-shell states there are NSO's with fractional occupation number, and at the same time nonvanishing elements of lambda2, which are related to spin and symmetry coupling. It is often useful to describe an open-shell state by a totally symmetric ensemble state. If one wants to treat a one-particle perturbation by means of perturbation theory, this mainly as a run-up for the study of a two-particle perturbation, one is faced with the problem that the perturbation expansion of the Liouville equation gives information only on the nondiagonal elements (in a basis of the unperturbed states) of gamma. There are essentially three possibilities to construct the diagonal elements of gamma: (i) to consider the perturbation expansion of the characteristic polynomial of gamma, especially the idempotency for closed-shell states, (ii) to rely on the ICSE1, which (at variance with the IBC1) also gives information on the diagonal elements, though not in a very efficient manner, and (iii) to formulate the perturbation theory in terms of a unitary transformation in Fock space. The latter is particularly powerful, especially, when one wishes to study realistic Hamiltonians with a two-body interaction. (c) 2004 American Institute of Physics

PREFACE: International Workshop on Statistical-Mechanical Informatics 2010

NASA Astrophysics Data System (ADS)

Inoue, Jun-ichi; Kabashima, Yoshiyuki; Tanaka, Kazuyuki; Tanaka, Toshiyuki

2010-04-01

Everything that exists in the natural world is made up of several types of elementary particles. However, we cannot understand nature simply by identifying the properties of these particles. This is because collections of the particles sometimes exhibit completely unexpected collective phenomena, quite independently of the individual particles' properties. In the physical sciences, the importance of focusing on the properties of objects composed of a large number of constituents is reflected in the phrase, "More is different." The main concept of the research project, the Grant-in-Aid for Scientific Research on Priority Areas `Deepening and Expansion of Statistical Mechanical Informatics (DEX-SMI)' (Head Investigator: Yoshiyuki Kabashima, Tokyo Institute of Technology) (Project Webpage DEX-SMI), launched in 2006, was to introduce this perspective into information science under the common slogan, "More is different in informatics as well." As milestones in the research activity, the International Workshop on Statistical-Mechanical Informatics (IW-SMI) was held annually, featuring studies of information and communication (2007), quantum information (2008), and bioinformatics (2009). The workshop series provided fruitful opportunities for leading researchers of various disciplines to interact with one another, which led to several collaborative studies. The final workshop, IW-SMI2010, was held at Shiran Kaikan, Kyoto University, Kyoto, Japan, on 7-10 March 2010 to wrap up the achievements of the four years of activity in the DEX-SMI research project. This workshop also aimed to bring together leading researchers in the physical and information sciences to discuss possible future directions for further exploring the successes of DEX-SMI. We would like to thank the contributors of the workshop as well as all the participants. We hope that the successes of IW-SMI2010 and DEX-SMI will lead to further development of this highly vigorous interdisciplinary field between statistical mechanics and information science. Editors Jun-ichi Inoue Yoshiyuki Kabashima Kazuyuki Tanaka Toshiyuki Tanaka The IW-SMI 2010 Organizing Committee: Masato Okada (University of Tokyo) Yoshiyuki Kabashima, General Chair (Tokyo Institute of Technology) Shin Ishii (Kyoto University) Jun-ichi Inoue, Publications Chair (Hokkaido University) Kazuyuki Tanaka (Tohoku University) Toshiyuki Tanaka, Vice-General Chair (Kyoto University)

CICART Center For Integrated Computation And Analysis Of Reconnection And Turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharjee, Amitava

CICART is a partnership between the University of New Hampshire (UNH) and Dartmouth College. CICART addresses two important science needs of the DoE: the basic understanding of magnetic reconnection and turbulence that strongly impacts the performance of fusion plasmas, and the development of new mathematical and computational tools that enable the modeling and control of these phenomena. The principal participants of CICART constitute an interdisciplinary group, drawn from the communities of applied mathematics, astrophysics, computational physics, fluid dynamics, and fusion physics. It is a main premise of CICART that fundamental aspects of magnetic reconnection and turbulence in fusion devices, smaller-scalemore » laboratory experiments, and space and astrophysical plasmas can be viewed from a common perspective, and that progress in understanding in any of these interconnected fields is likely to lead to progress in others. The establishment of CICART has strongly impacted the education and research mission of a new Program in Integrated Applied Mathematics in the College of Engineering and Applied Sciences at UNH by enabling the recruitment of a tenure-track faculty member, supported equally by UNH and CICART, and the establishment of an IBM-UNH Computing Alliance. The proposed areas of research in magnetic reconnection and turbulence in astrophysical, space, and laboratory plasmas include the following topics: (A) Reconnection and secondary instabilities in large high-Lundquist-number plasmas, (B) Particle acceleration in the presence of multiple magnetic islands, (C) Gyrokinetic reconnection: comparison with fluid and particle-in-cell models, (D) Imbalanced turbulence, (E) Ion heating, and (F) Turbulence in laboratory (including fusion-relevant) experiments. These theoretical studies make active use of three high-performance computer simulation codes: (1) The Magnetic Reconnection Code, based on extended two-fluid (or Hall MHD) equations, in an Adaptive Mesh Refinement (AMR) framework, (2) the Particle Simulation Code, a fully electromagnetic 3D Particle-In-Cell (PIC) code that includes a collision operator, and (3) GS2, an Eulerian, electromagnetic, kinetic code that is widely used in the fusion program, and simulates the nonlinear gyrokinetic equations, together with a self-consistent set of Maxwell’s equations.« less

Nuclear physics in particle therapy: a review

NASA Astrophysics Data System (ADS)

Durante, Marco; Paganetti, Harald

2016-09-01

Charged particle therapy has been largely driven and influenced by nuclear physics. The increase in energy deposition density along the ion path in the body allows reducing the dose to normal tissues during radiotherapy compared to photons. Clinical results of particle therapy support the physical rationale for this treatment, but the method remains controversial because of the high cost and of the lack of comparative clinical trials proving the benefit compared to x-rays. Research in applied nuclear physics, including nuclear interactions, dosimetry, image guidance, range verification, novel accelerators and beam delivery technologies, can significantly improve the clinical outcome in particle therapy. Measurements of fragmentation cross-sections, including those for the production of positron-emitting fragments, and attenuation curves are needed for tuning Monte Carlo codes, whose use in clinical environments is rapidly increasing thanks to fast calculation methods. Existing cross sections and codes are indeed not very accurate in the energy and target regions of interest for particle therapy. These measurements are especially urgent for new ions to be used in therapy, such as helium. Furthermore, nuclear physics hardware developments are frequently finding applications in ion therapy due to similar requirements concerning sensors and real-time data processing. In this review we will briefly describe the physics bases, and concentrate on the open issues.

Nuclear physics in particle therapy: a review.

PubMed

Durante, Marco; Paganetti, Harald

2016-09-01

Charged particle therapy has been largely driven and influenced by nuclear physics. The increase in energy deposition density along the ion path in the body allows reducing the dose to normal tissues during radiotherapy compared to photons. Clinical results of particle therapy support the physical rationale for this treatment, but the method remains controversial because of the high cost and of the lack of comparative clinical trials proving the benefit compared to x-rays. Research in applied nuclear physics, including nuclear interactions, dosimetry, image guidance, range verification, novel accelerators and beam delivery technologies, can significantly improve the clinical outcome in particle therapy. Measurements of fragmentation cross-sections, including those for the production of positron-emitting fragments, and attenuation curves are needed for tuning Monte Carlo codes, whose use in clinical environments is rapidly increasing thanks to fast calculation methods. Existing cross sections and codes are indeed not very accurate in the energy and target regions of interest for particle therapy. These measurements are especially urgent for new ions to be used in therapy, such as helium. Furthermore, nuclear physics hardware developments are frequently finding applications in ion therapy due to similar requirements concerning sensors and real-time data processing. In this review we will briefly describe the physics bases, and concentrate on the open issues.

Universal Decoherence under Gravity: A Perspective through the Equivalence Principle.

PubMed

Pang, Belinda H; Chen, Yanbei; Khalili, Farid Ya

2016-08-26

Pikovski et al. [Nat. Phys. 11, 668 (2015)] show that a composite particle prepared in a pure initial quantum state and propagated in a uniform gravitational field undergoes a decoherence process at a rate determined by the gravitational acceleration. By assuming Einstein's equivalence principle to be valid, we analyze a physical realization of the (1+1)D thought experiment of Pikovski et al. to demonstrate that the dephasing between the different internal states arises not from gravity but rather from differences in their rest mass, and the mass dependence of the de Broglie wave's dispersion relation. We provide an alternative view to the situation considered by Pikovski et al., where we propose that gravity plays a kinematic role by providing a relative velocity to the detector frame with respect to the particle; visibility can be easily recovered by giving the screen an appropriate uniform velocity. We then apply this insight to their thought experiment in (1+1)D to draw a direct correspondence, and obtain the same mathematical result for dephasing. We finally propose that dephasing due to gravity may in fact take place for certain modifications to the gravitational potential where the equivalence principle is violated.

The effects of high energy particles on planetary missions

NASA Technical Reports Server (NTRS)

Robinson, Paul A., Jr.

1988-01-01

Researchers review the background and motivation for the detailed study of the variability and uncertainty of the particle environment from a space systems planning perspective. The engineering concern raised by each environment is emphasized rather than the underlying physics of the magnetosphere or the sun. Missions now being planned span the short term range of one to three years to periods over ten years. Thus the engineering interest is beginning to stretch over periods of several solar cycles. Coincidentally, detailed measurements of the environment are now becoming available over that period of time. Both short term and long term environmental predictions are needed for proper mission planning. Short term predictions, perhaps based on solar indices, real time observations, or short term systematics, are very useful in near term planning -- launches, EVAs (extravehicular activities), coordinated observations, and experiments which require the magnetosphere to be in a certain state. Long term predictions of both average and extreme conditions are essential to mission design. Engineering considerations are many times driven by the worst case environment. Knowledge of the average conditions and their variability allows trade-off studies to be made, implementation of designs which degrade gracefully under multi-stress environments.

Underwater Light Regimes in Rivers from Multiple Measurement Approaches

NASA Astrophysics Data System (ADS)

Gardner, J.; Ensign, S.; Houser, J.; Doyle, M.

2017-12-01

Underwater light regimes are complex over space and time. Light in rivers is less understood compared to other aquatic systems, yet light is often the limiting resource and a fundamental control of many biological and physical processes in riverine systems. We combined multiple measurement approaches (fixed-site and flowpath) to understand underwater light regimes. We measured vertical light profiles over time (fixed-site) with stationary buoys and over space and time (flowpath) with Lagrangian neutrally buoyant sensors in two different large US rivers; the Upper Mississippi River in Wisconsin, USA and the Neuse River in North Carolina, USA. Fixed site data showed light extinction coefficients, and therefore the depth of the euphotic zone, varied up to three-fold within a day. Flowpath data revealed the stochastic nature of light regimes from the perspective of a neutrally buoyant particle as it moves throughout the water column. On average, particles were in the euphotic zone between 15-50% of the time. Combining flowpath and fixed-site data allowed spatial disaggregation of a river reach to determine if changes in the light regime were due to space or time as well as development of a conceptual model of the dynamic euphotic zone of rivers.

Anaerobic wastewater treatment and membrane filtration: a one night stand or a sustainable relationship?

PubMed

Jeison, D; van Lier, J B

2008-01-01

Several anaerobic membrane bioreactors (AnMBR) were operated, under various conditions, applying different reactor configurations. Applicable fluxes were strongly determined by the physical properties of the sludge present in the reactors. Results show that particle size is a key determining factor for the attainable fluxes. Under thermophilic conditions, small sludge particle size was observed, resulting in low critical fluxes reaching 6-7 L/m2h for the submerged configuration and acidified substrate. In contrast, under mesophilic conditions critical fluxes of 20 L/m2h were obtained. The acidification level also showed a strong effect. Under thermophilic conditions, the presence of a significant fraction of non-acidified organic matter induced the growth of suspended acidogenic biomass that seriously affected the applicable fluxes, both in submerged and side-stream configurations. Under all conditions tested cake formation showed to be the limiting factor determining the applicable fluxes. Only low levels of irreversible fouling were observed. Due to technical and economical considerations, most interesting perspectives for the application of AnMBR are expected with the treatment of high-strength particulate wastewaters, and with extreme wastewaters characterised by high temperature, salinity, etc.

Study on law of negative corona discharge in microparticle-air two-phase flow media

NASA Astrophysics Data System (ADS)

He, Bo; Li, Tianwei; Xiu, Yaping; Zhao, Heng; Peng, Zongren; Meng, Yongpeng

2016-03-01

To study the basic law of negative corona discharge in solid particle-air two-phase flow, corona discharge experiments in a needle-plate electrode system at different voltage levels and different wind speed were carried out in the wind tunnel. In this paper, the change law of average current and current waveform were analyzed, and the observed phenomena were systematically explained from the perspectives of airflow, particle charging, and particle motion with the help of PIV (particle image velocity) measurements and ultraviolet observations.

CERN launches high-school internship programme

NASA Astrophysics Data System (ADS)

Johnston, Hamish

2017-07-01

The CERN particle-physics lab has hosted 22 high-school students from Hungary in a pilot programme designed to show teenagers how science, technology, engineering and mathematics is used at the particle-physics lab.

Quarked! - Adventures in Particle Physics Education

NASA Astrophysics Data System (ADS)

MacDonald, Teresa; Bean, Alice

2009-01-01

Particle physics is a subject that can send shivers down the spines of students and educators alike-with visions of long mathematical equations and inscrutable ideas. This perception, along with a full curriculum, often leaves this topic the road less traveled until the latter years of school. Particle physics, including quarks, is typically not introduced until high school or university.1,2 Many of these concepts can be made accessible to younger students when presented in a fun and engaging way. Informal science institutions are in an ideal position to communicate new and challenging science topics in engaging and innovative ways and offer a variety of educational enrichment experiences for students that support and enhance science learning.3 Quarked!™ Adventures in the Subatomic Universe, a National Science Foundation EPSCoR-funded particle physics education program, provides classroom programs and online educational resources.

Detectors for Particle Radiation

NASA Astrophysics Data System (ADS)

Kleinknecht, Konrad

1999-01-01

This textbook provides a clear, concise and comprehensive review of the physical principles behind the devices used to detect charged particles and gamma rays, and the construction and performance of these many different types of detectors. Detectors for high-energy particles and radiation are used in many areas of science, especially particle physics and nuclear physics experiments, nuclear medicine, cosmic ray measurements, space sciences and geological exploration. This second edition includes all the latest developments in detector technology, including several new chapters covering micro-strip gas chambers, silicion strip detectors and CCDs, scintillating fibers, shower detectors using noble liquid gases, and compensating calorimeters for hadronic showers. This well-illustrated textbook contains examples from the many areas in science in which these detectors are used. It provides both a coursebook for students in physics, and a useful introduction for researchers in other fields.

Nuclear and particle physics, astrophysics and cosmology (NPAC) capability review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redondo, Antonio

2010-01-01

The present document represents a summary self-assessment of the status of the Nuclear and Particle Physics, Astrophysics and Cosmology (NPAC) capability across Los Alamos National Laboratory (LANL). For the purpose of this review, we have divided the capability into four theme areas: Nuclear Physics, Particle Physics, Astrophysics and Cosmology, and Applied Physics. For each theme area we have given a general but brief description of the activities under the area, a list of the Laboratory divisions involved in the work, connections to the goals and mission of the Laboratory, a brief description of progress over the last three years, ourmore » opinion of the overall status of the theme area, and challenges and issues.« less

Cosmic-ray transport in the heliosphere: A global perspective

NASA Astrophysics Data System (ADS)

Florinski, Vladimir

2013-02-01

Earth is shielded from the hazardous galactic radiation in the form or cosmic ray ions by the outwardly flow of the solar wind plasma and by the geomagnetic field. Understanding the effects of the global structure of the heliosphere on the transport of energetic charged particles remains an important challenge in space physics. The expanding bubble of the supersonic solar wind cools the populations of GeV ions that penetrate deeply into the interplanetary space. Beyond the solar wind lies the heliosheath that is believed to act as a long-term storage reservoir for the cosmic rays. The heliosheath and its magnetic field topology play an important role in modulating cosmic rays at large heliocentric distances. Understanding this role is crucial for interpreting the the puzzling Voyager spacecraft observations near the edge of the solar system.

Evolution of Planetary Ringmoon Systems

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.

1995-01-01

The last few decades have seen an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of these systems as our intuition (and our computers) catch up with the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is an emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system.

Partially composite particle physics with and without supersymmetry

NASA Astrophysics Data System (ADS)

Kramer, Thomas A.

Theories in which the Standard Model fields are partially compositeness provide elegant and phenomenologically viable solutions to the Hierarchy Problem. In this thesis we will study types of models from two different perspectives. We first derive an effective field theory describing the interactions of the Standard Models fields with their lightest composite partners based on two weakly coupled sectors. Technically, via the AdS/CFT correspondence, our model is dual to a highly deconstructed theory with a single warped extra-dimension. This two sector theory provides a simplified approach to the phenomenology of this important class of theories. We then use this effective field theoretic approach to study models with weak scale accidental supersymmetry. Particularly, we will investigate the possibility that the Standard Model Higgs field is a member of a composite supersymmetric sector interacting weakly with the known Standard Model fields.

Oscillatory multiphase flow strategy for chemistry and biology.

PubMed

Abolhasani, Milad; Jensen, Klavs F

2016-07-19

Continuous multiphase flow strategies are commonly employed for high-throughput parameter screening of physical, chemical, and biological processes as well as continuous preparation of a wide range of fine chemicals and micro/nano particles with processing times up to 10 min. The inter-dependency of mixing and residence times, and their direct correlation with reactor length have limited the adaptation of multiphase flow strategies for studies of processes with relatively long processing times (0.5-24 h). In this frontier article, we describe an oscillatory multiphase flow strategy to decouple mixing and residence times and enable investigation of longer timescale experiments than typically feasible with conventional continuous multiphase flow approaches. We review current oscillatory multiphase flow technologies, provide an overview of the advancements of this relatively new strategy in chemistry and biology, and close with a perspective on future opportunities.

Fundamental Principles of Classical Mechanics: a Geometrical Perspectives

NASA Astrophysics Data System (ADS)

Lam, Kai S.

2014-07-01

Classical mechanics is the quantitative study of the laws of motion for oscopic physical systems with mass. The fundamental laws of this subject, known as Newton's Laws of Motion, are expressed in terms of second-order differential equations governing the time evolution of vectors in a so-called configuration space of a system (see Chapter 12). In an elementary setting, these are usually vectors in 3-dimensional Euclidean space, such as position vectors of point particles; but typically they can be vectors in higher dimensional and more abstract spaces. A general knowledge of the mathematical properties of vectors, not only in their most intuitive incarnations as directed arrows in physical space but as elements of abstract linear vector spaces, and those of linear operators (transformations) on vector spaces as well, is then indispensable in laying the groundwork for both the physical and the more advanced mathematical - more precisely topological and geometrical - concepts that will prove to be vital in our subject. In this beginning chapter we will review these properties, and introduce the all-important related notions of dual spaces and tensor products of vector spaces. The notational convention for vectorial and tensorial indices used for the rest of this book (except when otherwise specified) will also be established...

Particle Physics at the Cosmic, Intensity, and Energy Frontiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Essig, Rouven

Major efforts at the Intensity, Cosmic, and Energy frontiers of particle physics are rapidly furthering our understanding of the fundamental constituents of Nature and their interactions. The overall objectives of this research project are (1) to interpret and develop the theoretical implications of the data collected at these frontiers and (2) to provide the theoretical motivation, basis, and ideas for new experiments and for new analyses of experimental data. Within the Intensity Frontier, an experimental search for a new force mediated by a GeV-scale gauge boson will be carried out with the $A'$ Experiment (APEX) and the Heavy Photon Searchmore » (HPS), both at Jefferson Laboratory. Within the Cosmic Frontier, contributions are planned to the search for dark matter particles with the Fermi Gamma-ray Space Telescope and other instruments. A detailed exploration will also be performed of new direct detection strategies for dark matter particles with sub-GeV masses to facilitate the development of new experiments. In addition, the theoretical implications of existing and future dark matter-related anomalies will be examined. Within the Energy Frontier, the implications of the data from the Large Hadron Collider will be investigated. Novel search strategies will be developed to aid the search for new phenomena not described by the Standard Model of particle physics. By combining insights from all three particle physics frontiers, this research aims to increase our understanding of fundamental particle physics.« less

News Particle Physics: ATLAS unveils mural at CERN Prize: Corti Trust invites essay entries Astrophysics: CERN holds cosmic-ray conference Researchers in Residence: Lord Winston returns to school Music: ATLAS scientists record physics music Conference: Champagne flows at Reims event Competition: Students triumph at physics olympiad Teaching: Physics proves popular in Japanese schools Forthcoming Events

NASA Astrophysics Data System (ADS)

2011-01-01

Particle Physics: ATLAS unveils mural at CERN Prize: Corti Trust invites essay entries Astrophysics: CERN holds cosmic-ray conference Researchers in Residence: Lord Winston returns to school Music: ATLAS scientists record physics music Conference: Champagne flows at Reims event Competition: Students triumph at physics olympiad Teaching: Physics proves popular in Japanese schools Forthcoming Events

Hybrid colored noise process with space-dependent switching rates

NASA Astrophysics Data System (ADS)

Bressloff, Paul C.; Lawley, Sean D.

2017-07-01

A fundamental issue in the theory of continuous stochastic process is the interpretation of multiplicative white noise, which is often referred to as the Itô-Stratonovich dilemma. From a physical perspective, this reflects the need to introduce additional constraints in order to specify the nature of the noise, whereas from a mathematical perspective it reflects an ambiguity in the formulation of stochastic differential equations (SDEs). Recently, we have identified a mechanism for obtaining an Itô SDE based on a form of temporal disorder. Motivated by switching processes in molecular biology, we considered a Brownian particle that randomly switches between two distinct conformational states with different diffusivities. In each state, the particle undergoes normal diffusion (additive noise) so there is no ambiguity in the interpretation of the noise. However, if the switching rates depend on position, then in the fast switching limit one obtains Brownian motion with a space-dependent diffusivity of the Itô form. In this paper, we extend our theory to include colored additive noise. We show that the nature of the effective multiplicative noise process obtained by taking both the white-noise limit (κ →0 ) and fast switching limit (ɛ →0 ) depends on the order the two limits are taken. If the white-noise limit is taken first, then we obtain Itô, and if the fast switching limit is taken first, then we obtain Stratonovich. Moreover, the form of the effective diffusion coefficient differs in the two cases. The latter result holds even in the case of space-independent transition rates, where one obtains additive noise processes with different diffusion coefficients. Finally, we show that yet another form of multiplicative noise is obtained in the simultaneous limit ɛ ,κ →0 with ɛ /κ2 fixed.

Physical characterization of aerosol particles during the Chinese New Year’s firework events

NASA Astrophysics Data System (ADS)

Zhang, Min; Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Wang, Tao; Yang, Xin; Gong, Youguo; Geng, Fuhai; Chen, Changhong

2010-12-01

Measurements for particles 10 nm to 10 μm were taken using a Wide-range Particle Spectrometer during the Chinese New Year (CNY) celebrations in 2009 in Shanghai, China. These celebrations provided an opportunity to study the number concentration and size distribution of particles in an especial atmospheric pollution situation due to firework displays. The firework activities had a clear contribution to the number concentration of small accumulation mode particles (100-500 nm) and PM 1 mass concentration, with a maximum total number concentration of 3.8 × 10 4 cm -3. A clear shift of particles from nucleation and Aitken mode to small accumulation mode was observed at the peak of the CNY firework event, which can be explained by reduced atmospheric lifetimes of smaller particles via the concept of the coagulation sink. High particle density (2.7 g cm -3) was identified as being particularly characteristic of the firework aerosols. Recalculated fine particles PM 1 exhibited on average above 150 μg m -3 for more than 12 hours, which was a health risk to susceptible individuals. Integral physical parameters of firework aerosols were calculated for understanding their physical properties and further model simulation.

Light scattering and absorption by space weathered planetary bodies: Novel numerical solution

NASA Astrophysics Data System (ADS)

Markkanen, Johannes; Väisänen, Timo; Penttilä, Antti; Muinonen, Karri

2017-10-01

Airless planetary bodies are exposed to space weathering, i.e., energetic electromagnetic and particle radiation, implantation and sputtering from solar wind particles, and micrometeorite bombardment.Space weathering is known to alter the physical and chemical composition of the surface of an airless body (C. Pieters et al., J. Geophys. Res. Planets, 121, 2016). From the light scattering perspective, one of the key effects is the production of nanophase iron (npFe0) near the exposed surfaces (B. Hapke, J. Geophys. Res., 106, E5, 2001). At visible and ultraviolet wavelengths these particles have a strong electromagnetic response which has a major impact on scattering and absorption features. Thus, to interpret the spectroscopic observations of space-weathered asteroids, the model should treat the contributions of the npFe0 particles rigorously.Our numerical approach is based on the hierarchical geometric optics (GO) and radiative transfer (RT). The modelled asteroid is assumed to consist of densely packed silicate grains with npFe0 inclusions. We employ our recently developed RT method for dense random media (K. Muinonen, et al., Radio Science, submitted, 2017) to compute the contributions of the npFe0 particles embedded in silicate grains. The dense media RT method requires computing interactions of the npFe0 particles in the volume element for which we use the exact fast superposition T-matrix method (J. Markkanen, and A.J. Yuffa, JQSRT 189, 2017). Reflections and refractions on the grain surface and propagation in the grain are addressed by the GO. Finally, the standard RT is applied to compute scattering by the entire asteroid.Our numerical method allows for a quantitative interpretation of the spectroscopic observations of space-weathered asteroids. In addition, it may be an important step towards more rigorous a thermophysical model of asteroids when coupled with the radiative and conductive heat transfer techniques.Acknowledgments. Research supported by European Research Council with Advanced Grant No. 320773 SAEMPL. Computational resources provided by CSC- IT Centre for Science Ltd, Finland.

Chemical Inscriptions in Korean Textbooks: Semiotics of Macro- and Microworld

ERIC Educational Resources Information Center

Han, Jae Young; Roth, Wolff-Michael

2006-01-01

Thinking about macroscopic phenomena in terms of models based on the idea of microscopic particles (i.e., the particulate theory of matter) is one of the important goals for student learning in chemistry around the world. However, previous research suggests that students do not easily understand phenomena from a particle perspective, although such…

DISPERSION POLYMERIZATIONS OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE: THE INFLUENCE OF HELIUM CONCENTRATION ON PARTICLE SIZE AND PARTICLE SIZE DISTRIBUTION. (R826115)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

DOES THE HARVARD/U.S. ENVIRONMENTAL PROTECTION AGENCY AMBIENT PARTICLE CONCENTRATOR CHANGE THE TOXIC POTENTIAL OF PARTICLES? (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Characterizing physical properties and heterogeneous chemistry of single particles in air using optical trapping-Raman spectroscopy

NASA Astrophysics Data System (ADS)

Gong, Z.; Wang, C.; Pan, Y. L.; Videen, G.

2017-12-01

Heterogeneous reactions of solid particles in a gaseous environment are of increasing interest; however, most of the heterogeneous chemistry studies of airborne solids were conducted on particle ensembles. A close examination on the heterogeneous chemistry between single particles and gaseous-environment species is the key to elucidate the fundamental mechanisms of hydroscopic growth, cloud nuclei condensation, secondary aerosol formation, etc., and reduce the uncertainty of models in radiative forcing, climate change, and atmospheric chemistry. We demonstrate an optical trapping-Raman spectroscopy (OT-RS) system to study the heterogeneous chemistry of the solid particles in air at single-particle level. Compared to other single-particle techniques, optical trapping offers a non-invasive, flexible, and stable method to isolate single solid particle from substrates. Benefited from two counter-propagating hollow beams, the optical trapping configuration is adaptive to trap a variety of particles with different materials from inorganic substitution (carbon nanotubes, silica, etc.) to organic, dye-doped polymers and bioaerosols (spores, pollen, etc.), with different optical properties from transparent to strongly absorbing, with different sizes from sub-micrometers to tens of microns, or with distinct morphologies from loosely packed nanotubes to microspheres and irregular pollen grains. The particles in the optical trap may stay unchanged, surface degraded, or optically fragmented according to different laser intensity, and their physical and chemical properties are characterized by the Raman spectra and imaging system simultaneously. The Raman spectra is able to distinguish the chemical compositions of different particles, while the synchronized imaging system can resolve their physical properties (sizes, shapes, morphologies, etc.). The temporal behavior of the trapped particles also can be monitored by the OT-RS system at an indefinite time with a resolution from 10 ms to 5 min, which can be further applied to monitor the dynamics of heterogeneous reactions. The OT-RS system provides a flexible method to characterize and monitor the physical properties and heterogeneous chemistry of optically trapped solid particles in gaseous environment at single-particle level.

Particle Physics, 2nd Edition

NASA Astrophysics Data System (ADS)

Martin, B. R.; Shaw, G.

1998-01-01

Particle Physics, Second Edition is a concise and lucid account of the fundamental constituents of matter. The standard model of particle physics is developed carefully and systematically, without heavy mathematical formalism, to make this stimulating subject accessible to undergraduate students. Throughout, the emphasis is on the interpretation of experimental data in terms of the basic properties of quarks and leptons, and extensive use is made of symmetry principles and Feynman diagrams, which are introduced early in the book. The Second Edition brings the book fully up to date, including the discovery of the top quark and the search for the Higgs boson. A final short chapter is devoted to the continuing search for new physics beyond the standard model. Particle Physics, Second Edition features: * A carefully structured and written text to help students understand this exciting and demanding subject. * Many worked examples and problems to aid student learning. Hints for solving the problems are given in an Appendix. * Optional "starred" sections and appendices, containing more specialised and advanced material for the more ambitious reader.

Decoupling the Role of Inertia and Gravity on Particle Dispersion

NASA Technical Reports Server (NTRS)

Rogers, Chris; Squires, Kyle

1996-01-01

Turbulent gas flows laden with small, dense particles are encountered in a wide number of important applications in both industrial settings and aerodynamics applications. Particle interactions with the underlying turbulent flow are exceedingly complex and, consequently, difficult to accurately model. The difficulty arises primarily due to the fact that response of a particle to the local environment is dictated by turbulence properties in the reference frame moving with the particle (particle-Lagrangian). The particle-Lagrangian reference frame is in turn dependent upon the particle relaxation time (time constant) as well as gravitational drift. The combination of inertial and gravitational effects in this frame complicates our ability to accurately predict particle-laden flows since measurements in the particle-Lagrangian reference frame are difficult to obtain. Therefore, in this work we will examine separately the effects of inertia and gravitational drift on particle dispersion through a combination of physical and numerical experiments. In this study, particle-Lagrangian measurements will be obtained in physical experiments using stereo image velocimetry. Gravitational drift will be varied in the variable-g environments of the NASA DC-9 and in the zero-g environment at the drop tower at NASA-Lewis. Direct numerical simulations will be used to corroborate the measurements from the variable-g experiments. We expect that this work will generate new insight into the underlying physics of particle dispersion and will, in turn, lead to more accurate models of particle transport in turbulent flows.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quigg, C.

The author sketches some pressing questions in several active areas of particle physics and outline the challenges they present for the design and operation of detectors. His assignment at the 1999 ICFA Instrumentation School is to survey some current developments in particle physics, and to describe the kinds of experiments they would like to do in the near future and illustrate the demands their desires place on detectors and data analysis. Like any active science, particle physics is in a state of continual renewal. Many of the subjects that seem most fascinating and most promising today simply did not existmore » as recently as twenty-five years ago. Other topics that have preoccupied physicists for many years have been reshaped by recent discoveries and insights, and transformed by new techniques in accelerator science and detector technology. To provide some context for the courses and laboratories at this school, he has chosen three topics that are of high scientific interest, and that place very different demands on instrumental techniques. He hopes that you will begin to see the breadth of opportunities in particle physics, and that you will also look beyond the domain of particle physics for opportunities to apply the lessons you learn here in Istanbul.« less

Bioaccessibility studies of ferro-chromium alloy particles for a simulated inhalation scenario: a comparative study with the pure metals and stainless steel.

PubMed

Midander, Klara; de Frutos, Alfredo; Hedberg, Yolanda; Darrie, Grant; Wallinder, Inger Odnevall

2010-07-01

The European product safety legislation, REACH, requires that companies that manufacture, import, or use chemicals demonstrate safe use and high level of protection of their products placed on the market from a human health and environmental perspective. This process involves detailed assessment of potential hazards for various toxicity endpoints induced by the use of chemicals with a minimum use of animal testing. Such an assessment requires thorough understanding of relevant exposure scenarios including material characteristics and intrinsic properties and how, for instance, physical and chemical properties change from the manufacturing phase, throughout use, to final disposal. Temporary or permanent adverse health effects induced by particles depend either on their shape or physical characteristics, and/or on chemical interactions with the particle surface upon human exposure. Potential adverse effects caused by the exposure of metal particles through the gastrointestinal system, the pulmonary system, or the skin, and their subsequent potential for particle dissolution and metal release in contact with biological media, show significant gaps of knowledge. In vitro bioaccessibility testing at conditions of relevance for different exposure scenarios, combined with the generation of a detailed understanding of intrinsic material properties and surface characteristics, are in this context a useful approach to address aspects of relevance for accurate risk and hazard assessment of chemicals, including metals and alloys and to avoid the use of in vivo testing. Alloys are essential engineering materials in all kinds of applications in society, but their potential adverse effects on human health and the environment are very seldom assessed. Alloys are treated in REACH as mixtures of their constituent elements, an approach highly inappropriate because intrinsic properties of alloys generally are totally different compared with their pure metal components. A large research effort was therefore conducted to generate quantitative bioaccessibility data for particles of ferro-chromium alloys compared with particles of the pure metals and stainless steel exposed at in vitro conditions in synthetic biological media of relevance for particle inhalation and ingestion. All results are presented combining bioaccessibility data with aspects of particle characteristics, surface composition, and barrier properties of surface oxides. Iron and chromium were the main elements released from ferro-chromium alloys upon exposure in synthetic biological media. Both elements revealed time-dependent release processes. One week exposures resulted in very small released particle fractions being less than 0.3% of the particle mass at acidic conditions and less than 0.001% in near pH-neutral media. The extent of Fe released from ferro-chromium alloy particles was significantly lower compared with particles of pure Fe, whereas Cr was released to a very low and similar extent as from particles of pure Cr and stainless steel. Low release rates are a result of a surface oxide with passive properties predominantly composed of chromium(III)-rich oxides and silica and, to a lesser extent, of iron(II,III)oxides. Neither the relative bulk alloy composition nor the surface composition can be used to predict or assess the extent of metals released in different synthetic biological media. Ferro-chromium alloys cannot be assessed from the behavior of their pure metal constituents. (c) 2009 SETAC.

TH-E-201-03: A Radiology Resident’s Perspectives of Physics Teaching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Key, A.

The ABR Core Examination stresses integrating physics into real-world clinical practice and, accordingly, has shifted its focus from passive recall of facts to active application of physics principles. Physics education of radiology residents poses a challenge. The traditional method of didactic lectures alone is insufficient, yet it is difficult to incorporate physics teaching consistently into clinical rotations due to time constraints. Faced with this challenge, diagnostic medical physicists who teach radiology residents, have been thinking about how to adapt their teaching to the new paradigm, what to teach and meet expectation of the radiology resident and the radiology residency program.more » The proposed lecture attempts to discuss above questions. Newly developed diagnostic radiology residents physics curriculum by the AAPM Imaging Physics Curricula Subcommittee will be reviewed. Initial experience on hands-on physics teaching will be discussed. Radiology resident who will have taken the BAR Core Examination will share the expectation of physics teaching from a resident perspective. The lecture will help develop robust educational approaches to prepare radiology residents for safer and more effective lifelong practice. Learning Objectives: Learn updated physics requirements for radiology residents Pursue effective approaches to teach physics to radiology residents Learn expectation of physics teaching from resident perspective J. Zhang, This topic is partially supported by RSNA Education Scholar Grant.« less

How Students Manage the Didactic Contract? Contribution of the Didactic Perspective to Research in Physical Education Classroom.

ERIC Educational Resources Information Center

Amade-Escot, Chantal

This study investigated how and why students modified instructional tasks, explaining modifications using the concept of didactic contract. The study focused on two theoretical perspectives in physical education (PE) research: didactic and ecological. The didactic paradigm examines relationships among teachers, students, and the content embedded…

Engineering Students' Experiences from Physics Group Work in Learning Labs

ERIC Educational Resources Information Center

Mellingsaeter, Magnus Strøm

2014-01-01

Background: This paper presents a case study from a physics course at a Norwegian university college, investigating key aspects of a group-work project, so-called learning labs, from the participating students' perspective. Purpose: In order to develop these learning labs further, the students' perspective is important. Which aspects are essential…

Perspectives of Students with Disabilities toward Physical Education: A Qualitative Inquiry Review

ERIC Educational Resources Information Center

Haegele, Justin A.; Sutherland, Sue

2015-01-01

The purpose of this article is to review published qualitative inquiries that examine the perspective of students with disabilities toward experiences in physical education. Keyword searches were used to identify articles from electronic databases published from 1995 to 2014. Thirteen articles met all inclusion criteria, and findings were…

Psychosocial Perspectives on Girls and Women in Sport and Physical Activity: A Tribute to Dorothy V. Harris.

ERIC Educational Resources Information Center

Feltz, Deborah L.

1992-01-01

Introduces theme issue of this journal on the psychosocial influences on girls and women in sport and physical activity, focusing on the work of Dorothy V. Harris who battled for equal sporting opportunities and benefits for females. The papers are written from a feminist perspective. (SM)

Battling Obesity in K-12 Learners from an Exercise Physiology Perspective

ERIC Educational Resources Information Center

Rattigan, Peter; Biren, Greg

2007-01-01

Physical education practitioners and programs have the opportunity and obligation to help children become physically educated, healthy, and active adults. This article discusses the battle against obesity in K-12 learners from an exercise physiology perspective and focuses on the fact that practitioners have all the tools they need to battle this…

Evaluating University Physical Activity Courses from Student and Instructor Perspectives

ERIC Educational Resources Information Center

Beaudoin, Christina; Parker, Tonya; Tiemersma, Karol; Lewis, Colleen

2018-01-01

This article presents the results of a survey of student and faculty perspectives within a university-level instructional physical activity (PA) program. The results revealed that students enrolled in the courses primarily for enjoyment and to stay fit. A majority of students ranked the quality of instruction as excellent, were interested in new…

Teaching Perspectives of Pre-Service Physical Education Teachers: The Shanghai Experience

ERIC Educational Resources Information Center

Wang, Lijuan

2014-01-01

Background: In the physical education (PE) domain, teachers are given the freedom to make important educational decisions. Because of the common assumption that the decisions teachers make are based on a set of educational perspectives, a considerable number of studies have addressed the importance of studying the thinking and beliefs of PE…

Reconceptualizing Motivational Climate in Physical Education and Sport Coaching: An Interdisciplinary Perspective

ERIC Educational Resources Information Center

Morgan, Kevin

2017-01-01

The purpose of this article is to re-conceptualize the phenomenon of motivational climate in Physical Education and sport coaching as a concept that is not purely psychological in nature, but also highly dependent upon pedagogical and sociological theories. In doing so, an interdisciplinary perspective is promoted where the three aforementioned…

Particle transport and deposition: basic physics of particle kinetics.

PubMed

Tsuda, Akira; Henry, Frank S; Butler, James P

2013-10-01

The human body interacts with the environment in many different ways. The lungs interact with the external environment through breathing. The enormously large surface area of the lung with its extremely thin air-blood barrier is exposed to particles suspended in the inhaled air. The particle-lung interaction may cause deleterious effects on health if the inhaled pollutant aerosols are toxic. Conversely, this interaction can be beneficial for disease treatment if the inhaled particles are therapeutic aerosolized drugs. In either case, an accurate estimation of dose and sites of deposition in the respiratory tract is fundamental to understanding subsequent biological response, and the basic physics of particle motion and engineering knowledge needed to understand these subjects is the topic of this article. A large portion of this article deals with three fundamental areas necessary to the understanding of particle transport and deposition in the respiratory tract. These are: (i) the physical characteristics of particles, (ii) particle behavior in gas flow, and (iii) gas-flow patterns in the respiratory tract. Other areas, such as particle transport in the developing lung and in the diseased lung are also considered. The article concludes with a summary and a brief discussion of areas of future research. © 2013 American Physiological Society. Compr Physiol 3:1437-1471, 2013.

A pedagogical derivation of the matrix element method in particle physics data analysis

NASA Astrophysics Data System (ADS)

Sumowidagdo, Suharyo

2018-03-01

The matrix element method provides a direct connection between the underlying theory of particle physics processes and detector-level physical observables. I am presenting a pedagogically-oriented derivation of the matrix element method, drawing from elementary concepts in probability theory, statistics, and the process of experimental measurements. The level of treatment should be suitable for beginning research student in phenomenology and experimental high energy physics.

Instrumentation for Applied Physics and Industrial Applications

NASA Astrophysics Data System (ADS)

Hillemanns, H.; Le Goff, J.-M.

This document is part of Part 2 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '7.3 Instrumentation for Applied Physics and Industrial Applications' of Chapter '7 Applications of Detectors in Technology; Medicine and Other Fields' with the content:

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zieb, Kristofer James Ekhart; Hughes, Henry Grady III; Xu, X. George

The release of version 6.2 of the MCNP6 radiation transport code is imminent. To complement the newest release, a summary of the heavy charged particle physics models used in the 1 MeV to 1 GeV energy regime is presented. Several changes have been introduced into the charged particle physics models since the merger of the MCNP5 and MCNPX codes into MCNP6. Here, this article discusses the default models used in MCNP6 for continuous energy loss, energy straggling, and angular scattering of heavy charged particles. Explanations of the physics models’ theories are included as well.

Design evaluations for a flight cloud physics holocamera. [holographic/photographic camera for low-g Atmospheric Cloud Physics Laboratory

NASA Technical Reports Server (NTRS)

Moore, W. W., Jr.; Kurtz, R. L.; Lemons, J. F.

1976-01-01

The paper describes a holographic/photographic camera to be used with the zero-g or low-g Atmospheric Cloud Physics Laboratory. The flight prototype holocamera is intended to record particles from 0.01 to 5 microns for an optimum two-dimensional plane only in the microscopic photography mode, particles on a volume basis in the in-line holography mode from 5 microns up, and all particle sizes possible on a volume basis in the acute sideband holography mode.

Anti-gravity: The key to 21st century physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noyes, H.P.

1993-01-01

The masses coupling constants and cosmological parameters obtained using our discrete and combinatorial physics based on discrimination between bit-strings indicate that we can achieve the unification of quantum mechanics with relativity which had become the goal of twentieth century physics. To broaden our case we show that limitations on measurement of the position and velocity of an individual massive particle observed in a colliding beam scattering experiment imply real, rational commutation relations between position and velocity. Prior to this limit being pushed down to quantum effects, the lower bound is set by the available technology, but is otherwise scale invariant.more » Replacing force by force per unit mass and force per unit charge allows us to take over the Feynman-Dyson proof of the Maxwell Equations and extend it to weak gravity. The crossing symmetry of the individual scattering processes when one or more particles are replaced by anti-particles predicts both Coulomb attraction (for charged particles) and a Newtonian repulsion between any particle and its anti-particle. Previous quantum results remain intact, and predict the expected relativistic fine structure and spin dependencies. Experimental confirmation of this anti-gravity prediction would inaugurate the physics of the twenty-first century.« less

Anti-gravity: The key to 21st century physics

NASA Astrophysics Data System (ADS)

Noyes, H. P.

1993-01-01

The masses coupling constants and cosmological parameters obtained using our discrete and combinatorial physics based on discrimination between bit-strings indicate that we can achieve the unification of quantum mechanics with relativity which had become the goal of twentieth century physics. To broaden our case we show that limitations on measurement of the position and velocity of an individual massive particle observed in a colliding beam scattering experiment imply real, rational commutation relations between position and velocity. Prior to this limit being pushed down to quantum effects, the lower bound is set by the available technology, but is otherwise scale invariant. Replacing force by force per unit mass and force per unit charge allows us to take over the Feynman-Dyson proof of the Maxwell Equations and extend it to weak gravity. The crossing symmetry of the individual scattering processes when one or more particles are replaced by anti-particles predicts both Coulomb attraction (for charged particles) and a Newtonian repulsion between any particle and its anti-particle. Previous quantum results remain intact, and predict the expected relativistic fine structure and spin dependencies. Experimental confirmation of this anti-gravity prediction would inaugurate the physics of the twenty-first century.

In situ real-time measurement of physical characteristics of airborne bacterial particles

NASA Astrophysics Data System (ADS)

Jung, Jae Hee; Lee, Jung Eun

2013-12-01

Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

Semi-Lagrangian particle methods for high-dimensional Vlasov-Poisson systems

NASA Astrophysics Data System (ADS)

Cottet, Georges-Henri

2018-07-01

This paper deals with the implementation of high order semi-Lagrangian particle methods to handle high dimensional Vlasov-Poisson systems. It is based on recent developments in the numerical analysis of particle methods and the paper focuses on specific algorithmic features to handle large dimensions. The methods are tested with uniform particle distributions in particular against a recent multi-resolution wavelet based method on a 4D plasma instability case and a 6D gravitational case. Conservation properties, accuracy and computational costs are monitored. The excellent accuracy/cost trade-off shown by the method opens new perspective for accurate simulations of high dimensional kinetic equations by particle methods.

Multi-Scale Computational Analyses of JP-8 Fuel Droplets and Vapors in Human Respiratory Airway Models

DTIC Science & Technology

2007-10-31

equation of ultrafine particles , or (JP-8) fuel vapor, whose dominant radial transfer mechanisms are Brownian motion and turbulent dispersion is given in...Deposition of ultrafine particles at carinal ridges of the upper bronchial airways. Aerosol Science and Technology 38, 991-1000. Comer, J.K...from studies of ultrafine particles . Environmental Health Perspectives 113, 823-839. Ritchie, G., Still, K., Rossi III, J., Bekkedal, M., Bobb, A. and

Physics Accomplishments and Future Prospects of the BES Experiments at the Beijing Electron-Positron Collider

NASA Astrophysics Data System (ADS)

Briere, Roy A.; Harris, Frederick A.; Mitchell, Ryan E.

2016-10-01

The cornerstone of the Chinese experimental particle physics program is a series of experiments performed in the τ-charm energy region. China began building e+e- colliders at the Institute for High Energy Physics in Beijing more than three decades ago. Beijing Electron Spectrometer (BES) is the common root name for the particle physics detectors operated at these machines. We summarize the development of the BES program and highlight the physics results across several topical areas.

Future time perspective and health behaviors: temporal framing of self-regulatory processes in physical exercise and dietary behaviors.

PubMed

Gellert, Paul; Ziegelmann, Jochen P; Lippke, Sonia; Schwarzer, Ralf

2012-04-01

Limitations in perceived lifetime can undermine long-term goal striving. Planning is supposed to translate intentions into health behaviors and to operate as a compensatory strategy to overcome goal striving deficits associated with a limited time perspective. Two longitudinal studies were conducted examining the compensatory role of planning: an online survey on fruit and vegetable consumption (N = 909; 16-78 years; follow-up at 4 months) and a questionnaire study on physical exercise in older adults (N = 289; 60-95 years, over a half-year period). Intentions, planning, and behavior were measured in a behavior-specific, future time perspective in a generic manner. Planning mediated between intentions and both health behaviors. Time perspective operated as a moderator, indicating that in individuals with a more limited time perspective, a stronger effect of planning on health behaviors emerged. Planning as a self-regulatory strategy may compensate for a limited time perspective.

Alternative approaches to research in physical therapy: positivism and phenomenology.

PubMed

Shepard, K F; Jensen, G M; Schmoll, B J; Hack, L M; Gwyer, J

1993-02-01

This article presents philosophical approaches to research in physical therapy. A comparison is made to demonstrate how the research purpose, research design, research methods, and research data differ when one approaches research from the philosophical perspective of positivism (predominantly quantitative) as compared with the philosophical perspective of phenomenology (predominantly qualitative). Differences between the two approaches are highlighted by examples from research articles published in Physical Therapy. The authors urge physical therapy researchers to become familiar with the tenets, rigor, and knowledge gained from the use of both approaches in order to increase their options in conducting research relevant to the practice of physical therapy.

Theoretical physics: Quarks fuse to release energy

NASA Astrophysics Data System (ADS)

Miller, Gerald A.

2017-11-01

In nuclear fusion, energy is produced by the rearrangement of protons and neutrons. The discovery of an analogue of this process involving particles called quarks has implications for both nuclear and particle physics. See Letter p.89

Phase-factor-dependent symmetries and quantum phases in a three-level cavity QED system.

PubMed

Fan, Jingtao; Yu, Lixian; Chen, Gang; Jia, Suotang

2016-05-03

Unlike conventional two-level particles, three-level particles may support some unitary-invariant phase factors when they interact coherently with a single-mode quantized light field. To gain a better understanding of light-matter interaction, it is thus necessary to explore the phase-factor-dependent physics in such a system. In this report, we consider the collective interaction between degenerate V-type three-level particles and a single-mode quantized light field, whose different components are labeled by different phase factors. We mainly establish an important relation between the phase factors and the symmetry or symmetry-broken physics. Specifically, we find that the phase factors affect dramatically the system symmetry. When these symmetries are breaking separately, rich quantum phases emerge. Finally, we propose a possible scheme to experimentally probe the predicted physics of our model. Our work provides a way to explore phase-factor-induced nontrivial physics by introducing additional particle levels.

A Bubble Chamber Simulator: A New Tool for the Physics Classroom

ERIC Educational Resources Information Center

Gagnon, Michel

2011-01-01

Mainly used in the 1960s, bubble chambers played a major role in particle physics. Now replaced with modern electronic detectors, we believe they remain an important didactic tool to introduce particle physics as they provide visual, appealing and insightful pictures. Sadly, this rare type of detector is mostly accessible through open-door events…

Donald Glaser, the Bubble Chamber, and Elementary Particles

Science.gov Websites

Effects of Ionizing Radiation on the Formation of Bubbles in Liquids Physical Review, Vol. 87, Issue 4 , 665, August 15, 1952 Characteristics of Bubble Chambers Physical Review, Vol. 97, Issue 2, 474-479 Chambers Physical Review, Vol. 102, Issue 6, 1653-1658, June 15, 1956 Methods of Particle Detection for

Hands on CERN: A Well-Used Physics Education Project

ERIC Educational Resources Information Center

Johansson, K. E.

2006-01-01

The "Hands on CERN" education project makes it possible for students and teachers to get close to the forefront of scientific research. The project confronts the students with contemporary physics at its most fundamental level with the help of particle collisions from the DELPHI particle physics experiment at CERN. It now exists in 14 languages…

Plasmonic Resonances for Spectroscopy Applications using 3D Finite-Difference Time-Domain Models

NASA Astrophysics Data System (ADS)

Ravi, Aruna

Tuning plasmonic extinction resonances of sub-wavelength scale structures is essential to achieve maximum sensitivity and accuracy. These resonances can be controlled with careful design of nanoparticle geometries and incident wave attributes. In the first part of this dissertation, plasmonically enhanced effects on hexagonal-arrays of metal nanoparticles, metal-hole arrays (micro-mesh), and linear-arrays of metal nanorings are analyzed using three-dimensional Finite-Difference Time-Domain (3D-FDTD) simulations. The effect of particle size, lattice spacing, and lack of monodispersity of a self-assembled, hexagonal array layer of silver (Ag) nanoparticles on the extinction resonance is investigated to help determine optimal design specifications for efficient organic solar power harvesting. The enhancement of transmission resonances using plasmonic thin metal films with arrays of holes which enable recording of scatter-free infrared (IR) transmission spectra of individual particles is also explored. This method is quantitative, non-destructive and helps in better understanding the interaction of light with sub-wavelength particles. Next, plasmonically enhanced effects on linear arrays of gold (Au) rings are studied. Simulations employing 3D-FDTD can be used to determine the set of geometrical parameters to attain localized surface plasmon resonance (LSPR). The shifts in resonances due to changes in the effective dielectric of the structure are investigated, which is useful in sensing applications. Computational models enrich experimental studies. In the second part of this dissertation, the effect of particle size, shape and orientation on the IR spectra is investigated using 3D-FDTD and Mie-Bruggeman models. This computational analysis is extended to include clusters of particles of mixed composition. The prediction of extinction and absorption spectra of single particles of mixed composition helps in interpreting their physical properties and predict chemical composition. The chemical composition of respirable particles is of great interest from health, atmospheric, and environmental perspectives. Different environments may pose different hazards and spectroscopic challenges. Common mineral components of airborne and atmospheric dust samples have strong IR transitions with wavelengths that match particle size, giving rise to interesting lineshape distortions. These models enable the determination of volume fractions of components in individual particles that are mixtures of many materials, as are the dust particles inhaled into people's lungs.

Fast Inference of Deep Neural Networks in FPGAs for Particle Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duarte, Javier; Han, Song; Harris, Philip

Recent results at the Large Hadron Collider (LHC) have pointed to enhanced physics capabilities through the improvement of the real-time event processing techniques. Machine learning methods are ubiquitous and have proven to be very powerful in LHC physics, and particle physics as a whole. However, exploration of the use of such techniques in low-latency, low-power FPGA hardware has only just begun. FPGA-based trigger and data acquisition (DAQ) systems have extremely low, sub-microsecond latency requirements that are unique to particle physics. We present a case study for neural network inference in FPGAs focusing on a classifier for jet substructure which wouldmore » enable, among many other physics scenarios, searches for new dark sector particles and novel measurements of the Higgs boson. While we focus on a specific example, the lessons are far-reaching. We develop a package based on High-Level Synthesis (HLS) called hls4ml to build machine learning models in FPGAs. The use of HLS increases accessibility across a broad user community and allows for a drastic decrease in firmware development time. We map out FPGA resource usage and latency versus neural network hyperparameters to identify the problems in particle physics that would benefit from performing neural network inference with FPGAs. For our example jet substructure model, we fit well within the available resources of modern FPGAs with a latency on the scale of 100 ns.« less

Center for Theoretical Underground Physics and Related Areas – CETUP*2016 Summer Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szczerbinska, Barbara

For last six years Center for Theoretical Underground Physics and Related Areas (CETUP*) successfully provided a stimulating environment for creative thinking and open communication between researches of varying ages and nationalities in dynamic atmosphere of intense scientific interactions. Ongoing and proposed Neutrino and Dark Matter experiments are expected to unveil the answers to fundamental questions about the Universe. CETUP*2016 was focused exactly on these subjects bringing together experts in dark matter, neutrino physics, particle and nuclear physics, astrophysics and cosmology from around the world. Scientists invited to participate in the program not only provided theoretical support to the underground science,more » but they also examined core questions including: What is the nature of dark matter?, What is the origin of the neutrino masses?, How well do we know the neutrino parameters?, How have neutrinos shaped the evolution of the universe?, , What are the fundamental underlying symmetries of the Universe? Is there a Grand Unified Theory of the Universe? and many others. The 2016 CETUP* summer program consisted of three sessions (June 6 – July 16, 2016) covering various aspects of theoretical and experimental neutrino physics, unification and dark matter. The two week long session on Physics and Instrumentation of the Near Detector for the Long-Baseline Neutrino Experiments (June 6 – June 16) was followed by the two week long Neutrino Physics/Unification session: “From Grand Unification to String Theory and Back” (June 20 – July 2). The program ended with two week long session on Dark Matter Physics (July 4 – July 16). This six-week long program allowed for thorough discussions and an effective and comprehensive analysis of topics related to Dark Matter, Dark Energy, Neutrino Physics including astrophysical neutrinos, near and far detector physics, neutrino interactions, Higgs Boson, Inflation, Leptogenesis and many others that will advance the knowledge in particle and nuclear physics, astrophysics and cosmology. The scientific program usually consisted of 2-3 hour-long talks on selected subjects in dark matter and neutrino physics from both theoretical and experimental perspective and followed by extended in depth discussions. The format of the program accommodated separate discussion sessions where the outstanding issues of the disciplines were explored, for example: The Future of Large Physics Projects in the US, and the Role of Theory in the Future of US Physics. 2016 CETUP* summer program was attended by over 70 national and international scientists (including 17 graduate students, 16 postdocs and 39 senior scientists) from over 48 different universities and laboratories. CETUP* participants were very active senior and junior members of the community in order to make the discussions informative and productive. CETUP* 2016 provided a stimulating venue for the exchange of scientific ideas among experts in dark matter, neutrino physics, particle physics, astrophysics and cosmology. During Dark Matter session thirty-seven scientific talks and extended discussions were presented. Twenty-nine talks and discussions were conducted during the Neutrino Physics sessions by international Neutrino Physics experts. The power point presentations for the talks and discussions can be found on the CETUP* website: http://research.dsu.edu/cetup/agenda.aspx. Based on the collaborations established during CETUP* already ten preprints were published and many more are in preparation: https://research.dsu.edu/cetup/preprints.aspx?cetupYear=2016. The proceedings from CETUP*2016 are in preparation to be published by American Institute of Physics in summer 2017. Multiple outreach efforts aimed to share the excitement of the research with K-12, teachers, undergraduate and graduate students as well as the general public.« less

Gravitational collapse of dark energy field configurations and supermassive black hole formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jhalani, V.; Kharkwal, H.; Singh, A., E-mail: anupamsingh.iitk@gmail.com

Dark energy is the dominant component of the total energy density of our Universe. The primary interaction of dark energy with the rest of the Universe is gravitational. It is therefore important to understand the gravitational dynamics of dark energy. Since dark energy is a low-energy phenomenon from the perspective of particle physics and field theory, a fundamental approach based on fields in curved space should be sufficient to understand the current dynamics of dark energy. Here, we take a field theory approach to dark energy. We discuss the evolution equations for a generic dark energy field in curved space-timemore » and then discuss the gravitational collapse for dark energy field configurations. We describe the 3 + 1 BSSN formalism to study the gravitational collapse of fields for any general potential for the fields and apply this formalism to models of dark energy motivated by particle physics considerations. We solve the resulting equations for the time evolution of field configurations and the dynamics of space-time. Our results show that gravitational collapse of dark energy field configurations occurs and must be considered in any complete picture of our Universe. We also demonstrate the black hole formation as a result of the gravitational collapse of the dark energy field configurations. The black holes produced by the collapse of dark energy fields are in the supermassive black hole category with the masses of these black holes being comparable to the masses of black holes at the centers of galaxies.« less

Artium mater in relativistic astrophysics : New perspectives for a European-Latin American PhD program

NASA Astrophysics Data System (ADS)

Chardonnet, Pascal

2015-12-01

Following the successful scientific space missions by the European Space Agency (ESA) and the European Southern Observatory (ESO) in Chile, as well as the high-energy particle activities at CERN in Genve, we have created a Ph.D. program dedicated to the formation of scientists in the field of relativistic astrophysics. The students of such a program will lead the theoretical developments of one of the most active fields of research, based on the above observational and experimental facilities. This program needs expertise in the most advanced topics of mathematical and theoretical physics, and in relativistic field theories. It requires the ability to model the observational data received from the above facilities, as well as all the basic knowledge in astronomy, astrophysics and cosmology. This activity is necessarily international, no single university can cover the broad expertises. From this, the proposed program of the IRAP Ph.D., in one of the youngest and most dynamical French universities, pole of research and teaching in the Euro-Mediterranean region (PRES): the University of Nice. It benefits from the presence of the astrophysics research institute of Observatoire de la Cte d'Azur involved in relativistic and non-photonic astrophysics. The participation of the Freie Universitaet Berlin, Oldenburg and Bremen Universities and of the Einstein Institute in Potsdam offers the possibility of teaching in relativistic field theories at the highest level. The University of Savoy offers the link to the particle physics at CERN. The activities at the University of Rome, at Stockholm University and at ICRANet offer teaching programs in all the fields of relativistic astrophysics, including cosmology, the physics of gravitational collapse, gamma-ray bursts, and black hole physics. Finally, the University of Ferrara will be present with lectures and researches in the topics they have pioneered such as x-ray astrophysics and observational cosmology. Through ICRANet the extra-European connections with Brazil, China and India will be guaranteed: in China, with the Shanghai Observatory of the Chinese Academy of Science, studying the formation and evolution of large-scale structure and galaxies; in India, with the Indian Centre for Space Physics (ICSP), renowned for its research on compact objects as well as on solar physics and astrochemistry; in Brazil with ICRANet Brazil where a successful program of research and teaching in relativistic astrophysics has been established in recent years.

Artium mater in relativistic astrophysics : New perspectives for a European-Latin American PhD program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chardonnet, Pascal; LAPTh, Université de Savoie, CNRS, B.P. 110, Annecy-le-Vieux F-74941; ICRANet, Piazza della Repubblica 10, 65122 Pescara

Following the successful scientific space missions by the European Space Agency (ESA) and the European Southern Observatory (ESO) in Chile, as well as the high-energy particle activities at CERN in Genve, we have created a Ph.D. program dedicated to the formation of scientists in the field of relativistic astrophysics. The students of such a program will lead the theoretical developments of one of the most active fields of research, based on the above observational and experimental facilities. This program needs expertise in the most advanced topics of mathematical and theoretical physics, and in relativistic field theories. It requires the abilitymore » to model the observational data received from the above facilities, as well as all the basic knowledge in astronomy, astrophysics and cosmology. This activity is necessarily international, no single university can cover the broad expertises. From this, the proposed program of the IRAP Ph.D., in one of the youngest and most dynamical French universities, pole of research and teaching in the Euro-Mediterranean region (PRES): the University of Nice. It benefits from the presence of the astrophysics research institute of Observatoire de la Cte d’Azur involved in relativistic and non-photonic astrophysics. The participation of the Freie Universitaet Berlin, Oldenburg and Bremen Universities and of the Einstein Institute in Potsdam offers the possibility of teaching in relativistic field theories at the highest level. The University of Savoy offers the link to the particle physics at CERN. The activities at the University of Rome, at Stockholm University and at ICRANet offer teaching programs in all the fields of relativistic astrophysics, including cosmology, the physics of gravitational collapse, gamma-ray bursts, and black hole physics. Finally, the University of Ferrara will be present with lectures and researches in the topics they have pioneered such as x-ray astrophysics and observational cosmology. Through ICRANet the extra-European connections with Brazil, China and India will be guaranteed: in China, with the Shanghai Observatory of the Chinese Academy of Science, studying the formation and evolution of large-scale structure and galaxies; in India, with the Indian Centre for Space Physics (ICSP), renowned for its research on compact objects as well as on solar physics and astrochemistry; in Brazil with ICRANet Brazil where a successful program of research and teaching in relativistic astrophysics has been established in recent years.« less

The Multiverse and Particle Physics

NASA Astrophysics Data System (ADS)

Donoghue, John F.

2016-10-01

The possibility of fundamental theories with very many ground states, each with different physical parameters, changes the way that we approach the major questions of particle physics. Most importantly, it raises the possibility that these different parameters could be realized in different domains in the larger universe. In this review, I survey the motivations for the multiverse and the impact of the idea of the multiverse on the search for new physics beyond the Standard Model.

Scaling effects in direct shear tests

USGS Publications Warehouse

Orlando, A.D.; Hanes, D.M.; Shen, H.H.

2009-01-01

Laboratory experiments of the direct shear test were performed on spherical particles of different materials and diameters. Results of the bulk friction vs. non-dimensional shear displacement are presented as a function of the non-dimensional particle diameter. Simulations of the direct shear test were performed using the Discrete Element Method (DEM). The simulation results show Considerable differences with the physical experiments. Particle level material properties, such as the coefficients of static friction, restitution and rolling friction need to be known a priori in order to guarantee that the simulation results are an accurate representation of the physical phenomenon. Furthermore, laboratory results show a clear size dependency on the results, with smaller particles having a higher bulk friction than larger ones. ?? 2009 American Institute of Physics.

Comparisons of physical experiment and discrete element simulations of sheared granular materials in an annular shear cell

USGS Publications Warehouse

Ji, S.; Hanes, D.M.; Shen, H.H.

2009-01-01

In this study, we report a direct comparison between a physical test and a computer simulation of rapidly sheared granular materials. An annular shear cell experiment was conducted. All parameters were kept the same between the physical and the computational systems to the extent possible. Artificially softened particles were used in the simulation to reduce the computational time to a manageable level. Sensitivity study on the particle stiffness ensured such artificial modification was acceptable. In the experiment, a range of normal stress was applied to a given amount of particles sheared in an annular trough with a range of controlled shear speed. Two types of particles, glass and Delrin, were used in the experiment. Qualitatively, the required torque to shear the materials under different rotational speed compared well with those in the physical experiments for both the glass and the Delrin particles. However, the quantitative discrepancies between the measured and simulated shear stresses were nearly a factor of two. Boundary conditions, particle size distribution, particle damping and friction, including a sliding and rolling, contact force model, were examined to determine their effects on the computational results. It was found that of the above, the rolling friction between particles had the most significant effect on the macro stress level. This study shows that discrete element simulation is a viable method for engineering design for granular material systems. Particle level information is needed to properly conduct these simulations. However, not all particle level information is equally important in the study regime. Rolling friction, which is not commonly considered in many discrete element models, appears to play an important role. ?? 2009 Elsevier Ltd.

A Model for Generation of Martian Surface Dust, Soil and Rock Coatings: Physical vs. Chemical Interactions, and Palagonitic Plus Hydrothermal Alteration

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Murchie, S.; Pieters, C.; Zent, A.

1999-01-01

This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data from Mars and geologic analogs from terrestrial sites. One basic premise is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results. Physical processes distribute dust particles on rocks, forming physical rock coatings, and on the surface between rocks forming soil units; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces or duricrust surface units, both of which are relatively permanent materials. According to this model the mineral components of the dust/soil particles are derived from a combination of "typical" palagonitic weathering of volcanic ash and hydrothermally altered components, primarily from steam vents or fumeroles. Both of these altered materials are composed of tiny particles, about 1 micron or smaller, that are aggregates of silicates and iron oxide/oxyhydroxide/sulfate phases. Additional information is contained in the original extended abstract.

The lightness of being: mass, ether, and unification of the forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kronfeld, Andreas S.

2009-03-01

How can an electron be both a wave and a particle? At the same time? Because it is a quantum field. That key insight seems to be underappreciated, given the awe and mysticism that permeate most nontechnical discussions of modern physics. Perhaps the root of the problem is that most popularizations of quantum mechanics and of particle physics shy away from quantized fields, the natural language for microscopic phenomena. In 'The Lightness of Being: Mass, Ether, and the Unification of Forces', Frank Wilczek confronts quantum field theory head on, demystifying not only wave-particle duality but also the origin of massmore » for hadrons (that is, everyday matter). Wilczek is the Herman Feshbach Professor of Physics at MIT and a co-recipient of the 2004 Nobel Prize in Physics. His research has spanned almost all aspects of theoretical particle physics, with significant forays into condensed-matter physics and dense nuclear matter (condensed quark matter, one might say). Recurring themes are the richness of quantum chromodynamics (QCD) and the alluring ideas of unification. His breadth and depth make him a sought after speaker for colloquia and public lectures. Wilczek also contributes an occasional Reference Frame column to 'Physics Today'. The material in 'The Lightness of Being' reflects the scope of the author's research. The book consists of three parts: the quantum fields of QCD (the ether that makes mass), gravitation (the ether that feels mass), and unification. Part 1, which traces notions of mass from Isaac Newton's time through theoretical and computational results of the past 40 years, is the most substantial and original; it is rich, modern, and rooted in observed phenomena. Part 2 continues in the same vein as it connects gravity, also an observed phenomenon, to QCD. Part 3 is more conventional, for a popularization of particle physics, in its focus on speculative ideas that (still) await direct experimental tests. Readers of 'Physics Today' will know that Wilczek can write with wit, grace, and an uncanny facility for using lightweight language to express heavy-duty ideas. They will find much of that kind of writing in 'The Lightness of Being'. Wilczek addresses subtle ideas with vim and vigor. He avoids some of the jargon of quantum field theory; for example, he calls the vertex in a Feynman diagram a hub. In more ambitious terminology, he refers to space-filling, everfluctuating quantum fields--be they electrons, quarks, gluons, or gravity--as 'the Grid'. The term is supposed to be short and familiar, evoking the ubiquitous electric grid (and soon-to-beubiquitous computing grid). It also, for the expert, cleverly alludes to lattice gauge theory. Indeed, after vividly explaining how the dynamics of QCD and the constraints of Heisenberg uncertainty conspire to create mass from the Grid, Wilczek emphasizes that the picture is backed by lattice QCD computations of 'heroic' proportions. Unfortunately, too much of 'The Lightness' is laden with clunky affectation: silly names (a pulsed electron accelerator is called the 'ultrastroboscopic nanomicroscope'), sophomoric jokes ('hadron' is 'not a typo'), references to pop culture (Wilczek might have called quantum fields 'the Matrix, but the sequels tarnished that candidate'), and many pointless footnotes. In a public lecture the audience may guffaw at such jokes, but on the printed page they fall flat. Wilczek explains physics so well that the inappropriate humor is the biggest unexplained puzzle of the book. It is fine to be silly, even crude, as long as the reader's path to understanding is made easier. A joke can inform with an unexpected perspective or simply give the mind a pause to refresh. Some of the humor achieves such aims, but too many gags impede the pace of the otherwise fine exposition. Three appendices, a glossary, and a set of endnotes are crisp and sober. They are excellent. 'The Lightness of Being' is not unbearable, but it is weighed down with too much clutter to rank as a masterpiece. It's a pity: Wilczek's best writing--some of it in this book--is l« less

Shadows Constructing a Relationship between Light and Color Pigments by Physical and Mathematical Perspectives

ERIC Educational Resources Information Center

Yurumezoglu, Kemal; Karabey, Burak; Koyunkaya, Melike Yigit

2017-01-01

Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the linear dispersion of light. This paper focuses on progressing the understanding of shadows from physical and mathematical perspectives. A significant relationship between light and color pigments is demonstrated with the help of the concept of sets.…

The Status of Physics 12 in BC: Reflections from UBC Science Teacher Candidates.

ERIC Educational Resources Information Center

Nashon, Samson Madera

As part of attempts to find out why few high school science students take Physics 12, this case study sought University of British Columbia (UBC) science teacher educators' perspectives on the topic. A survey method employing questionnaires and interviews as part of the study was used to elicit science teacher candidates' perspectives. Forty-five…

The Transition from Distance to Online Education: Perspectives from the Educational Management Horizon

ERIC Educational Resources Information Center

Soderstrom, Tor; From, Jorgen; Lovqvist, Jeanette; Tornquist, Anette

2012-01-01

In Sweden, higher education has moved away from distance education, including physical meetings, to online education with no physical meetings at all. This article focuses on the shift from distance to online education using an educational management perspective that is based on economic, staff, and student data collected between 1994 and 2010…

College Students' Opinions of Engaging Approaches in a Physical Science Course

ERIC Educational Resources Information Center

Gonzalez-Espada, Wilson

2009-01-01

Physical science courses have historically been taught from a variety of perspectives or emphases. In many cases, the instructor decides on the perspective and textbook for nonscience majors, so students rarely have a voice in the decision. This top-down approach and a potential gap between what instructors and students expect from a general…

Fast Particle Methods for Multiscale Phenomena Simulations

NASA Technical Reports Server (NTRS)

Koumoutsakos, P.; Wray, A.; Shariff, K.; Pohorille, Andrew

2000-01-01

We are developing particle methods oriented at improving computational modeling capabilities of multiscale physical phenomena in : (i) high Reynolds number unsteady vortical flows, (ii) particle laden and interfacial flows, (iii)molecular dynamics studies of nanoscale droplets and studies of the structure, functions, and evolution of the earliest living cell. The unifying computational approach involves particle methods implemented in parallel computer architectures. The inherent adaptivity, robustness and efficiency of particle methods makes them a multidisciplinary computational tool capable of bridging the gap of micro-scale and continuum flow simulations. Using efficient tree data structures, multipole expansion algorithms, and improved particle-grid interpolation, particle methods allow for simulations using millions of computational elements, making possible the resolution of a wide range of length and time scales of these important physical phenomena.The current challenges in these simulations are in : [i] the proper formulation of particle methods in the molecular and continuous level for the discretization of the governing equations [ii] the resolution of the wide range of time and length scales governing the phenomena under investigation. [iii] the minimization of numerical artifacts that may interfere with the physics of the systems under consideration. [iv] the parallelization of processes such as tree traversal and grid-particle interpolations We are conducting simulations using vortex methods, molecular dynamics and smooth particle hydrodynamics, exploiting their unifying concepts such as : the solution of the N-body problem in parallel computers, highly accurate particle-particle and grid-particle interpolations, parallel FFT's and the formulation of processes such as diffusion in the context of particle methods. This approach enables us to transcend among seemingly unrelated areas of research.

Basics of particle therapy I: physics

PubMed Central

Park, Seo Hyun

2011-01-01

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfill the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest. PMID:22984664

Perspective on IUPAP-ICWIP conferences and USA Participation

NASA Astrophysics Data System (ADS)

White, Herman

2015-04-01

Starting in 1999, the (International Union of Pure and Applied Physics) IUPAP, General Assembly, passed a resolution to form an IUPAP Working Group on Women in Physics. This lead to a number of international conferences that focused on analyzing the then current status of and progress in promoting women in physics for each country and world wide as well as sharing physics research progress and participation. I was twice a member of the USA delegation and participated in two of the last three of these conferences. I will present a perspective on the USA participation and contribution to the efforts of the conferences.

Protocol for Direct Counterfactual Quantum Communication

NASA Astrophysics Data System (ADS)

Salih, Hatim; Li, Zheng-Hong; Al-Amri, M.; Zubairy, M. Suhail

2013-04-01

It has long been assumed in physics that for information to travel between two parties in empty space, “Alice” and “Bob,” physical particles have to travel between them. Here, using the “chained” quantum Zeno effect, we show how, in the ideal asymptotic limit, information can be transferred between Alice and Bob without any physical particles traveling between them.

Finally making sense of the double-slit experiment.

PubMed

Aharonov, Yakir; Cohen, Eliahu; Colombo, Fabrizio; Landsberger, Tomer; Sabadini, Irene; Struppa, Daniele C; Tollaksen, Jeff

2017-06-20

Feynman stated that the double-slit experiment "…has in it the heart of quantum mechanics. In reality, it contains the only mystery" and that "nobody can give you a deeper explanation of this phenomenon than I have given; that is, a description of it" [Feynman R, Leighton R, Sands M (1965) The Feynman Lectures on Physics ]. We rise to the challenge with an alternative to the wave function-centered interpretations: instead of a quantum wave passing through both slits, we have a localized particle with nonlocal interactions with the other slit. Key to this explanation is dynamical nonlocality, which naturally appears in the Heisenberg picture as nonlocal equations of motion. This insight led us to develop an approach to quantum mechanics which relies on pre- and postselection, weak measurements, deterministic, and modular variables. We consider those properties of a single particle that are deterministic to be primal. The Heisenberg picture allows us to specify the most complete enumeration of such deterministic properties in contrast to the Schrödinger wave function, which remains an ensemble property. We exercise this approach by analyzing a version of the double-slit experiment augmented with postselection, showing that only it and not the wave function approach can be accommodated within a time-symmetric interpretation, where interference appears even when the particle is localized. Although the Heisenberg and Schrödinger pictures are equivalent formulations, nevertheless, the framework presented here has led to insights, intuitions, and experiments that were missed from the old perspective.

Adolescents' perspectives on the barriers and facilitators of physical activity: a systematic review of qualitative studies.

PubMed

Martins, João; Marques, Adilson; Sarmento, Hugo; Carreiro da Costa, Francisco

2015-10-01

This article examined qualitative studies of adolescents' perspectives about the facilitators and barriers of physical activity, published from 2007 to 2014. A systematic review of 'Web of Science', 'EBSCO', 'Psychinfo' and 'ERIC' databases was performed according to Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines. The following keywords were used: 'physical activity' and 'physical education', each one individually associated with 'correlate', 'determinant', 'facilitator', 'barrier', 'factor influen*', and with 'qualitative', 'focus group', 'interview', "narrative'. Out of 3815 studies initially identified, due to inclusion and quality criteria, only 12 were fully reviewed. Studies' outcomes were analyzed through thematic analysis. The majority of these reported research with young adolescent girls. Few studies have considered the socioeconomic status influence. According to young people's perspectives, the main facilitators and hampering factors to their participation in physical activity were the following: attitude toward physical activity; motivation; perceptions of competence and body image; fun; influence of friends, family and physical education teachers and environmental physical activity opportunities. Specific life transition periods were referred only as a barrier to physical activity. Strategies of pedagogical actions and for developing physical activity intervention programs were discussed, in order to effectively promote the adoption of active lifestyles among youth. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The Response of the Ionospheric Cusp to the Solar Through Two Perspectives: Low Energy Changed Particle In-Situ Measurements and Low- Energy Neutral Atom Imaging

NASA Technical Reports Server (NTRS)

Coffey, V. N.; Moore, T. E.; Chandler, M. O.; Craven, P. D.

2000-01-01

The IMAGE mission provides a new perspective on the study of the response of the magnetosphere/ionosphere system to changing solar wind conditions, particularly the variability of ion outflow. Learning to interpret this new type of data becomes an essential step in the process of melding these results with the wealth of in-situ charged particle observations obtained over the past 25 years. In order to understand how the in-situ data correspond to and contrast with IMAGE results we will perform a conjunctive study of event data from two instruments to shed light on the coupling of the solar wind and ionosphere from these different perspectives. We will use the Low Energy Neutral Atom instrument (LENA) which images energetic neutral atom emissions from upward flowing ionospheric ions and the Thermal Ion Dynamics Instrument (TIDE) on the Polar satellite which measures in-situ ion outflow from 0.3-300 eV. Our primary goal will be to understand how comparing the imaging and in-situ perspectives can aid in the analysis of both data sets.

The Response of the Ionospheric Cusp to the Solar Wind Through Two Perspectives: Low Energy Charged Particle In-Situ Measurements and Low-Energy Neutral Atom Imaging

NASA Technical Reports Server (NTRS)

Coffey, V. N.; Moore, T. E.; Chandler, M. O.; Giles, B. L.; Craven, P. D.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission provides a new perspective on the study of the response of the magnetosphere/ionosphere system to changing solar wind conditions, particularly the variability of ion outflow. Learning to interpret this new type of data becomes an essential step in the process of melding these results with the wealth of in-situ charged particle observations obtained over the past 25 years. In order to understand how the in-situ data correspond to and contrast with IMAGE results we will perform a conjunctive study of event data from two instruments to shed light on the coupling of the solar wind and ionosphere from these different perspectives. We will use the Low Energy Neutral Atom instrument (LENA) which images energetic neutral atom emissions from upward flowing ionospheric ions and the Thermal Ion Dynamics Instrument (TIDE) on the Polar satellite which measures in-situ ion outflow from 0.3-300 eV. Our primary goal will be to understand how comparing the imaging and in-situ perspectives can aid in the analysis of both data sets.

Particle-fluid interactions for flow measurements

NASA Technical Reports Server (NTRS)

Berman, N. S.

1973-01-01

Study has been made of the motion of single particle and of group of particles, emphasizing solid particles in gaseous fluid. Velocities of fluid and particle are compared for several conditions of physical interest. Mean velocity and velocity fluctuations are calculated for single particle, and some consideration is given to multiparticle systems.

Long Pulse Operation on Tore-Supra: Towards Steady State

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreau, P.; Bucalossi, J.; Brosset, C.

The experimental programme of Tore Supra is devoted to the study of technology and physics issues associated to long-duration high performance discharges. This new domain of operation requires simultaneously and in steady state: heat removal capability, particle exhaust, fully non-inductive current drive, advanced technology integration and real time plasma control. The long discharge allows for addressing new time scale physic such as the wall particle retention and erosion. Moreover, the physics of fully non-inductive discharges is full of novelty, namely: the MHD stability, the slow spontaneous oscillation of the central electron temperature or the outstanding inward particle pinch.

Exploring the SCOAP3 Research Contributions of the United States

NASA Astrophysics Data System (ADS)

Marsteller, Matthew

2016-03-01

The Sponsoring Consortium for Open Access Publishing in Particle Physics (SCOAP3) is a successful global partnership of libraries, funding agencies and research centers. This presentation will inform the audience about SCOAP3 and also delve into descriptive statistics of the United States' intellectual contribution to particle physics via these open access journals. Exploration of the SCOAP3 particle physics literature using a variety of metrics tools such as Web of Science™, InCites™, Scopus® and SciVal will be shared. ORA or Sci2 will be used to visualize author collaboration networks.

Space physics educational outreach

NASA Technical Reports Server (NTRS)

Copeland, Richard A.

1995-01-01

The goal of this Space Physics Educational Outreach project was to develop a laboratory experiment and classroom lecture on Earth's aurora for use in lower division college physics courses, with the particular aim of implementing the experiment and lecture at Saint Mary's College of California. The strategy is to teach physics in the context of an interesting natural phenomenon by investigating the physical principles that are important in Earth's aurora, including motion of charged particles in electric and magnetic fields, particle collisions and chemical reactions, and atomic and molecular spectroscopy. As a by-product, the undergraduate students would develop an appreciation for naturally occurring space physics phenomena.

Precision Crystal Calorimeters in High Energy Physics

ScienceCinema

Ren-Yuan Zhu

2017-12-09

Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal’s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

2017 Topical Workshop on Electronics for Particle Physics

NASA Astrophysics Data System (ADS)

2017-09-01

The workshop will cover all aspects of electronics for particle physics experiments, and accelerator instrumentation of general interest to users. LHC experiments (and their operational experience) will remain a focus of the meeting but a strong emphasis on R&D for future experimentation will be maintained, such as SLHC, CLIC, ILC, neutrino facilities as well as other particle and astroparticle physics experiments. The purpose of the workshop is: To present results and original concepts for electronic research and development relevant to experiments as well as accelerator and beam instrumentation at future facilities; To review the status of electronics for the LHC experiments; To identify and encourage common efforts for the development of electronics; To promote information exchange and collaboration in the relevant engineering and physics communities.

[Application of nanoscale material in environmental remediation and its eco-environmental toxicity assessment: a review].

PubMed

Wang, Meng; Chen, Shi-Bao; Ma, Yi-Bing

2010-11-01

Though it has been claimed that nanotechnology has great potential in environmental cleaning, caution is required to the application of nano-particles (<100 nm). The studies relevant to organism exposure have shown that nano-particles can be hazardous. Currently, more papers are available about the remediation efficiency, characteristics, and mechanisms of manufactured nanoparticles after applied into polluted environment, but few studies are conducted about the ecotoxicological effects of the nano-particles. This paper reviewed the current researches on the hazards of nano- or ultrafine particles in environmental detoxification, discussed the potential environmental risks of applying nano-particles, and prospected the perspectives of the nanoparticles in environmental cleaning research.

Unraveling the Mysteries of the Atom.

ERIC Educational Resources Information Center

Lederman, Leon

1982-01-01

The development, role, and current research in particle physics at the Fermi National Accelerator Laboratory are reviewed, including discussions of its mission to understand the structure of matter, a brief history of particle physics, and the nature and applications of superconductivity, among other topics. (JN)

Perspectives: Nanofibers and nanowires for disordered photonics

NASA Astrophysics Data System (ADS)

Pisignano, Dario; Persano, Luana; Camposeo, Andrea

2017-03-01

As building blocks of microscopically non-homogeneous materials, semiconductor nanowires and polymer nanofibers are emerging component materials for disordered photonics, with unique properties of light emission and scattering. Effects found in assemblies of nanowires and nanofibers include broadband reflection, significant localization of light, strong and collective multiple scattering, enhanced absorption of incident photons, synergistic effects with plasmonic particles, and random lasing. We highlight recent related discoveries, with a focus on material aspects. The control of spatial correlations in complex assemblies during deposition, the coupling of modes with efficient transmission channels provided by nanofiber waveguides, and the embedment of random architectures into individually coded nanowires will allow the potential of these photonic materials to be fully exploited, unconventional physics to be highlighted, and next-generation optical devices to be achieved. The prospects opened by this technology include enhanced random lasing and mode-locking, multi-directionally guided coupling to sensors and receivers, and low-cost encrypting miniatures for encoders and labels.

Planetary Ringmoon Systems

NASA Technical Reports Server (NTRS)

Cuzzi, J. N.; Morrison, David (Technical Monitor)

1994-01-01

The last decade has seen an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Much of the structure revealed was thoroughly puzzling and fired the imagination of workers in a variety of disciplines. Consequently, we have also seen steady progress in our understanding of these systems as our intuitions (and our computers) catch up with the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron to-several-meter size particles which comprise ring systems (refs 1-5). The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems and families of regular satellites are invariably found together, and there is an emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system.

Signatures of Mechanosensitive Gating.

PubMed

Morris, Richard G

2017-01-10

The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change. As an example, three distinct D-versus-σ "signatures" are calculated, corresponding to gating by dilation, gating by tilt, and gating by a combination of both dilation and tilt. Both advantages and disadvantages of the approach are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

To envision a new particle or change an existing law? Hypothesis formation and anomaly resolution for the curious case of the β decay spectrum

NASA Astrophysics Data System (ADS)

Gauderis, Tjerk

2014-02-01

This paper addresses the question of how scientists determine which type of hypothesis is most suitable for tackling a particular problem by examining the historical case of the anomalous β spectrum in early nuclear physics (1927-1934), a puzzle that occasioned the most diverse hypotheses amongst physicists at the time. It is shown that such determinations are most often implicitly informed by scientists' individual perspectives on the structural relations between the various elements of the theory and the problem at hand. In addition to this main result, it is suggested that Wolfgang Pauli's neutrino idea may well have been an adaptation of Ernst Rutherford's original and older neutron idea, which would provide evidence that the adaptation of older ideas is a more common practice than is often thought.

Fluid Mechanics and Heat Transfer of Liquid Precursor Droplets Injected into High-Temperature Plasmas

NASA Astrophysics Data System (ADS)

Basu, Saptarshi; Jordan, Eric H.; Cetegen, Baki M.

2008-03-01

Thermo-physical processes in liquid ceramic precursor droplets in plasma were modeled. Models include aerodynamic droplet break-up, droplet transport, as well as heat and mass transfer within individual droplets. Droplet size, solute concentration, and plasma temperature effects are studied. Results are discussed with the perspective of selecting processing conditions and injection parameters to obtain certain types of coating microstructures. Small droplets (<5 microns) are found to undergo volumetric precipitation and coating deposition with small unpyrolized material. Droplets can be made to undergo shear break-up by reducing surface tension and small droplets promote volumetric precipitation. Small particles reach substrate as molten splats resulting in denser coatings. Model predicts that larger droplets (>5 microns) tend to surface precipitate-forming shells with liquid core. They may be subjected to internal pressurization leading to shattering of shells and secondary atomization of liquid within. They arrive at the substrate as broken shells and unpyrolized material.

Quantum Brownian motion model for the stock market

NASA Astrophysics Data System (ADS)

Meng, Xiangyi; Zhang, Jian-Wei; Guo, Hong

2016-06-01

It is believed by the majority today that the efficient market hypothesis is imperfect because of market irrationality. Using the physical concepts and mathematical structures of quantum mechanics, we construct an econophysical framework for the stock market, based on which we analogously map massive numbers of single stocks into a reservoir consisting of many quantum harmonic oscillators and their stock index into a typical quantum open system-a quantum Brownian particle. In particular, the irrationality of stock transactions is quantitatively considered as the Planck constant within Heisenberg's uncertainty relationship of quantum mechanics in an analogous manner. We analyze real stock data of Shanghai Stock Exchange of China and investigate fat-tail phenomena and non-Markovian behaviors of the stock index with the assistance of the quantum Brownian motion model, thereby interpreting and studying the limitations of the classical Brownian motion model for the efficient market hypothesis from a new perspective of quantum open system dynamics.

Method and apparatus for separating material

DOEpatents

Oder, Robin R.; Jamison, Russell E.

2006-10-24

An apparatus for sorting particles composed of a mixture of particles with differing physical and chemical characteristics. The apparatus includes a comminutor, a mechanism for removing particles from the inside of the comminutor which are intermediate in size between the feed to the comminutor and the product of comminution, a mechanism for either discharging particles taken from the comminutor to a reject stream or providing them to a size classification apparatus such as screening, a mechanism for returning the oversize particles to the comminutor or for discharging them to the reject stream, an electric mechanism for separating particles with an electrical force disposed adjacent to a magnet mechanism, a mechanism for providing the particles to the magnet mechanism and the electric mechanism and for providing triboelectric and capacitive charges to the particles, and a mechanism for returning one of the products of electric and magnetic separation to the comminutor while discharging the other to the reject stream. A method for sorting particles composed of a mixture of particles with differing physical and chemical characteristics.

Nanoparticle-Cell Interaction: A Cell Mechanics Perspective.

PubMed

Septiadi, Dedy; Crippa, Federica; Moore, Thomas Lee; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

2018-05-01

Progress in the field of nanoparticles has enabled the rapid development of multiple products and technologies; however, some nanoparticles can pose both a threat to the environment and human health. To enable their safe implementation, a comprehensive knowledge of nanoparticles and their biological interactions is needed. In vitro and in vivo toxicity tests have been considered the gold standard to evaluate nanoparticle safety, but it is becoming necessary to understand the impact of nanosystems on cell mechanics. Here, the interaction between particles and cells, from the point of view of cell mechanics (i.e., bionanomechanics), is highlighted and put in perspective. Specifically, the ability of intracellular and extracellular nanoparticles to impair cell adhesion, cytoskeletal organization, stiffness, and migration are discussed. Furthermore, the development of cutting-edge, nanotechnology-driven tools based on the use of particles allowing the determination of cell mechanics is emphasized. These include traction force microscopy, colloidal probe atomic force microscopy, optical tweezers, magnetic manipulation, and particle tracking microrheology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physics Group Work in a Phenomenographic Perspective--Learning Dynamics as the Experience of Variation and Relevance

ERIC Educational Resources Information Center

Ingerman, Ake; Berge, Maria; Booth, Shirley

2009-01-01

In this paper, we analyse learning dynamics in the context of physics group work of the kind increasingly found in engineering education. We apply a phenomenographic perspective on learning, seeing the notion of variation as the basic mechanism of learning. Empirically, we base our analysis on data from first year engineering students discussing…

Healthy from the Start: New Perspectives on Childhood Fitness. Teacher Education Monograph, No. 15.

ERIC Educational Resources Information Center

Leppo, Marjorie L., Ed.; Summerfield, Liane M., Ed.

The physical fitness status of children ages 6-12 is the topic of discussion in this monograph. The publication is organized into 4 major sections and 17 chapters. The first section, "An Introduction to Childhood Fitness," includes 3 chapters: (1) Status of Physical Fitness in U.S. Children; (2) The Public Health Perspective:…

Successful After-School Physical Activity Clubs in Urban High Schools: Perspectives of Adult Leaders and Student Participants

ERIC Educational Resources Information Center

Garn, Alex C.; McCaughtry, Nate; Kulik, Noel L.; Kaseta, Michele; Maljak, Kim; Whalen, Laurel; Shen, Bo; Martin, Jeffrey J.; Fahlman, Mariane

2014-01-01

Grounded in social cognitive theory, the purpose of this study was to examine leaders' and students' perspectives of factors that contribute to effective voluntary after-school physical activity clubs. Data were collected over two-years via field observations (n= 115) and interviews with students (n= 278) and adult leaders (n= 126). Results…

A Sociocultural Perspective as a Curriculum Change in Health and Physical Education

ERIC Educational Resources Information Center

Cliff, Ken

2012-01-01

As a lens through which to read and understand a subject area and its curriculum content and issues, a sociocultural perspective is a recent and arguably significant change for the Health and Physical Education (HPE) Key Learning Area (KLA) in Australia. Its significance lies, first, in the fact that it seems to represent a notable departure from…

Potential Teachers' Appropriate and Inappropriate Application of Pedagogical Resources in a Model-Based Physics Course: A "Knowledge in Pieces" Perspective on Teacher Learning

ERIC Educational Resources Information Center

Harlow, Danielle B.; Bianchini, Julie A.; Swanson, Lauren H.; Dwyer, Hilary A.

2013-01-01

We used a "knowledge in pieces" perspective on teacher learning to document undergraduates' pedagogical resources in a model-based physics course for potential teachers. We defined pedagogical resources as small, discrete ideas about teaching science that are applied appropriately or inappropriately in specific contexts. Neither…

Experience, Intersubjectivity, and Reflection: A Human Science Perspective on Preparation of Future Professionals in Adaptive Physical Activity

ERIC Educational Resources Information Center

Standal, Øyvind F.; Rugseth, Gro

2016-01-01

The aim of this article is to show that and how philosophy and philosophical thinking can be of relevance for the preparation of future professionals in adaptive physical activity. To this end we utilize philosophical insights from the human science perspective on two central issues, namely experience and intersubjectivity, which are weaved…

Understanding Students' Motivation in Sport and Physical Education: From the Expectancy-Value Model and Self-Efficacy Theory Perspectives

ERIC Educational Resources Information Center

Gao, Zan; Lee, Amelia M.; Harrison, Louis, Jr.

2008-01-01

In this article, the roles of individuals' expectancy beliefs and incentives (i.e., task value, outcome expectancy) in sport and physical education are examined from expectancy-value model and self-efficacy theory perspectives. Overviews of the two theoretical frameworks and the conceptual and measurement issues are provided, followed by a review…

a New Ontological Perspective for Integration of Social and Physical Environments: Disability and Rehabilitation Context

NASA Astrophysics Data System (ADS)

Gharebaghi, Amin; Abolfazl Mostafavi, Mir

2016-06-01

Social dimension of environment is an important aspect that should be reflected in research works related to studying the interactions between human and the environment. However, this dimension is usually neglected when representing the environment in geographic information systems for different applications. For instance, disability as a result of the interaction between human and environment is influenced by social and physical dimensions of environment. Although, this aspect is highlighted in most conceptual disability models by defining various taxonomies of the environment, from ontological perspective justifying and connecting social dimension to the physical dimension of the environment is not clearly determined. Integrating social dimension of the environment with its physical dimension for disability studies is a challenging task, which is the main objective of the present study. Here, we review some of the disability models and their perspective about classifying the environment. Then, from ontological perspective, their limitations are discussed and a new approach for the classification of concepts form the environment is presented. This approach facilitates and simplifies integration of social dimension in ontologies for more effective assessment of disability issue in Geographic Information System.

Time perspective and the theory of planned behavior: moderate predictors of physical activity among central Appalachian adolescents.

PubMed

Gulley, Tauna; Boggs, Dusta

2014-01-01

The purpose of this study was to determine how well time perspective and the Theory of Planned Behavior (TPB) predicted physical activity among adolescents residing in the central Appalachian region of the United States. A descriptive, correlational design was used. The setting was a rural high school in central Appalachia. The sample included 185 students in grades 9 through 12. Data were collected in school. Variables included components of the TPB, time perspective, and various levels of exercise. Data were analyzed using Pearson's correlation coefficients and multiple regression analysis. The TPB was a moderate predictor of exercise frequency among central Appalachian adolescents, accounting for 42% of the variance. Time perspective did not add to the predictive ability of the TPB to predict exercise frequency in this sample. This study provides support for the TPB for predicting frequency of exercise among central Appalachian adolescents. By understanding the role of the TPB in predicting physical activity among adolescents, nurse practitioners will be able to adapt intervention strategies to improve the physical activity behaviors of this population. Copyright © 2014 National Association of Pediatric Nurse Practitioners. Published by Mosby, Inc. All rights reserved.

Infinite efficiency of the collisional Penrose process: Can a overspinning Kerr geometry be the source of ultrahigh-energy cosmic rays and neutrinos?

NASA Astrophysics Data System (ADS)

Patil, Mandar; Harada, Tomohiro; Nakao, Ken-ichi; Joshi, Pankaj S.; Kimura, Masashi

2016-05-01

The origin of the ultrahigh-energy particles we receive on Earth from outer space such as EeV cosmic rays and PeV neutrinos remains an enigma. All mechanisms known to us currently make use of electromagnetic interaction to accelerate charged particles. In this paper, we propose a mechanism exclusively based on gravity rather than electromagnetic interaction. We show that it is possible to generate ultrahigh-energy particles starting from particles with moderate energies using the collisional Penrose process in an overspinning Kerr spacetime transcending the Kerr bound only by an infinitesimal amount, i.e., with the Kerr parameter a =M (1 +ɛ ) , where we take the limit ɛ →0+. We consider two massive particles starting from rest at infinity that collide at r =M with divergent center-of-mass energy and produce two massless particles. We show that massless particles produced in the collision can escape to infinity with the ultrahigh energies exploiting the collisional Penrose process with the divergent efficiency η ˜1 /√{ɛ }→∞ . Assuming the isotropic emission of massless particles in the center-of-mass frame of the colliding particles, we show that half of the particles created in the collisions escape to infinity with the divergent energies, while the proportion of particles that reach infinity with finite energy is minuscule. To a distant observer, ultrahigh-energy particles appear to originate from a bright spot which is at the angular location ξ ˜2 M /robs with respect to the singularity on the side which is rotating toward the observer. We compute the spectrum of the high-energy massless particles and show that anisotropy in the emission in the center-of-mass frame leaves a distinct signature on its shape. Since the anisotropy is dictated by the differential cross section of the underlying particle physics process, the observation of the spectrum can constrain the particle physics model and serve as a unique probe into fundamental physics at ultrahigh energies at which particles collide. Thus, the existence of the near-extremal overspinning Kerr geometry in the Universe, either as a transient or permanent configuration, would have deep implications on astrophysics as well as fundamental particle physics.

T-Matrix Method and its Applications to Electromagnetic Scattering by Particles: A Current Perspective

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.; Travis, Larry D.; Mackowski, Daniel W.

2010-01-01

This note serves as a short introduction to the reprint of our article "T-matrix computations of light scattering by nonspherical particles: a review" (JQSRT 1996; 55:535:75). We first discuss the motivation for writing that article and explain its historical context. This is followed by a short overview of more recent developments.

Space Particle Hazard Measurement and Modeling

DTIC Science & Technology

2016-09-01

understand the interactions of the physical processes driving, then specify and ultimately predict the state of the energetic particle populations...Hudson, and B. T. Kress (2013), Direct observation of the CRAND proton radiation belt source, J. Geophys. Res. Space Physics , 118, doi:10.1002...anticritical temperature for spacecraft charging, J. Geophys Res.: Space Physics , 113, 2156-2202, doi: 10.1029/2008JA013161 2010 – Tested basic

Inertial microfluidic physics.

PubMed

Amini, Hamed; Lee, Wonhee; Di Carlo, Dino

2014-08-07

Microfluidics has experienced massive growth in the past two decades, and especially with advances in rapid prototyping researchers have explored a multitude of channel structures, fluid and particle mixtures, and integration with electrical and optical systems towards solving problems in healthcare, biological and chemical analysis, materials synthesis, and other emerging areas that can benefit from the scale, automation, or the unique physics of these systems. Inertial microfluidics, which relies on the unconventional use of fluid inertia in microfluidic platforms, is one of the emerging fields that make use of unique physical phenomena that are accessible in microscale patterned channels. Channel shapes that focus, concentrate, order, separate, transfer, and mix particles and fluids have been demonstrated, however physical underpinnings guiding these channel designs have been limited and much of the development has been based on experimentally-derived intuition. Here we aim to provide a deeper understanding of mechanisms and underlying physics in these systems which can lead to more effective and reliable designs with less iteration. To place the inertial effects into context we also discuss related fluid-induced forces present in particulate flows including forces due to non-Newtonian fluids, particle asymmetry, and particle deformability. We then highlight the inverse situation and describe the effect of the suspended particles acting on the fluid in a channel flow. Finally, we discuss the importance of structured channels, i.e. channels with boundary conditions that vary in the streamwise direction, and their potential as a means to achieve unprecedented three-dimensional control over fluid and particles in microchannels. Ultimately, we hope that an improved fundamental and quantitative understanding of inertial fluid dynamic effects can lead to unprecedented capabilities to program fluid and particle flow towards automation of biomedicine, materials synthesis, and chemical process control.

The pdf approach to turbulent polydispersed two-phase flows

NASA Astrophysics Data System (ADS)

Minier, Jean-Pierre; Peirano, Eric

2001-10-01

The purpose of this paper is to develop a probabilistic approach to turbulent polydispersed two-phase flows. The two-phase flows considered are composed of a continuous phase, which is a turbulent fluid, and a dispersed phase, which represents an ensemble of discrete particles (solid particles, droplets or bubbles). Gathering the difficulties of turbulent flows and of particle motion, the challenge is to work out a general modelling approach that meets three requirements: to treat accurately the physically relevant phenomena, to provide enough information to address issues of complex physics (combustion, polydispersed particle flows, …) and to remain tractable for general non-homogeneous flows. The present probabilistic approach models the statistical dynamics of the system and consists in simulating the joint probability density function (pdf) of a number of fluid and discrete particle properties. A new point is that both the fluid and the particles are included in the pdf description. The derivation of the joint pdf model for the fluid and for the discrete particles is worked out in several steps. The mathematical properties of stochastic processes are first recalled. The various hierarchies of pdf descriptions are detailed and the physical principles that are used in the construction of the models are explained. The Lagrangian one-particle probabilistic description is developed first for the fluid alone, then for the discrete particles and finally for the joint fluid and particle turbulent systems. In the case of the probabilistic description for the fluid alone or for the discrete particles alone, numerical computations are presented and discussed to illustrate how the method works in practice and the kind of information that can be extracted from it. Comments on the current modelling state and propositions for future investigations which try to link the present work with other ideas in physics are made at the end of the paper.

Considerations for planning and conducting clinic-based research in physical therapy.

PubMed

Fitzgerald, G K; Delitto, A

2001-08-01

There is growing demand to increase the volume of clinic-based research in physical therapy. Special considerations, unique to the planning and conduct of clinic-based research, need to be addressed to increase the likelihood that these studies will be completed successfully. The purposes of this perspective are to discuss factors affecting clinic-based research and to offer suggestions for addressing these problems when designing and conducting research studies in a clinical setting. This perspective discusses issues such as patient management, determining the availability of target patient populations, acquiring support from physical therapists and physicians, reporting and managing research-related injury or illness, and modifying or terminating projects. Some of the points made in this perspective are illustrated using examples from the authors' experiences in conducting clinical research.

IMPETUS - Interactive MultiPhysics Environment for Unified Simulations.

PubMed

Ha, Vi Q; Lykotrafitis, George

2016-12-08

We introduce IMPETUS - Interactive MultiPhysics Environment for Unified Simulations, an object oriented, easy-to-use, high performance, C++ program for three-dimensional simulations of complex physical systems that can benefit a large variety of research areas, especially in cell mechanics. The program implements cross-communication between locally interacting particles and continuum models residing in the same physical space while a network facilitates long-range particle interactions. Message Passing Interface is used for inter-processor communication for all simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fixation and chemical analysis of single fog and rain droplets

NASA Astrophysics Data System (ADS)

Kasahara, M.; Akashi, S.; Ma, C.-J.; Tohno, S.

Last decade, the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests, materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively, but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope, and SEX-EDX, particle-induced X-ray emission (PIXE) and micro-PIXE analyses, respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall.

Physics, mathematics and numerics of particle adsorption on fluid interfaces

NASA Astrophysics Data System (ADS)

Schmuck, Markus; Pavliotis, Grigorios A.; Kalliadasis, Serafim

2012-11-01

We study two arbitrary immiscible fuids where one phase contains small particles of the size of the interface and smaller. We primarily focus on charge-free particles with wetting characteristics described by the contact angle formed at the interface between the two phases and the particles. Based on the experimental observation that particles are adsorbed on the interface to reduce the interfacial energy and hence the surface tension as well, we formulate a free-energy functional that accounts for these physical effects. Using elements from calculus of variations and formal gradient flow theory, we derive partial differential equations describing the location of the interface and the density of the particles in the fluid phases. Via numerical experiments we analyse the time evolution of the surface tension, the particle concentration, and the free energy over time and reflect basic experimentally observed phenomena.

Physical characteristics of indigestible solids affect emptying from the fasting human stomach.

PubMed Central

Meyer, B; Beglinger, C; Neumayer, M; Stalder, G A

1989-01-01

Gastric emptying of indigestible solids depends on their size. It is not clear whether physical characteristics other than particle size affect emptying of indigestible solids from the fasting human stomach. We studied gastric emptying of three differently shaped particles, (cubes, spheres, rods) of either hard or soft consistency during the fasting state in human volunteers. The shape of indigestible particles did not affect their emptying. The area under the gastric emptying curve (AUC: particles x hour) was for hard cubes 24.7 (2.2), for hard spheres 27.9 (1.6), for hard rods 26.9 (2.7). All soft particles emptied faster than their identically shaped hard counterparts, but there was no difference among the three shapes (AUC for soft cubes: 29.2 (3.0), for soft spheres 32.0 (1.8), for soft rods 34.1 (1.2). If gastric emptying of hard and soft particles was compared independently of their shape, soft particles emptied significantly faster than hard ones: AUC 31.8 (1.2) v 26.5 (1.3) (p less than 0.01). In conclusion, the consistency but not the shape significantly affects gastric emptying. Specific physical characteristics other than size and shape may affect gastric emptying of indigestible particles which may be of importance in the design of drugs. PMID:2599438

Astroparticle physics and cosmology.

PubMed

Mitton, Simon

2006-05-20

Astroparticle physics is an interdisciplinary field that explores the connections between the physics of elementary particles and the large-scale properties of the universe. Particle physicists have developed a standard model to describe the properties of matter in the quantum world. This model explains the bewildering array of particles in terms of constructs made from two or three quarks. Quarks, leptons, and three of the fundamental forces of physics are the main components of this standard model. Cosmologists have also developed a standard model to describe the bulk properties of the universe. In this new framework, ordinary matter, such as stars and galaxies, makes up only around 4% of the material universe. The bulk of the universe is dark matter (roughly 23%) and dark energy (about 73%). This dark energy drives an acceleration that means that the expanding universe will grow ever larger. String theory, in which the universe has several invisible dimensions, might offer an opportunity to unite the quantum description of the particle world with the gravitational properties of the large-scale universe.

A Biopharmaceutical Industry Perspective on the Control of Visible Particles in Biotechnology-Derived Injectable Drug Products.

PubMed

Mathonet, Serge; Mahler, Hanns-Christian; Esswein, Stefan T; Mazaheri, Maryam; Cash, Patricia W; Wuchner, Klaus; Kallmeyer, Georg; Das, Tapan K; Finkler, Christof; Lennard, Andrew

2016-01-01

Regulatory monographs in Europe and the United States require drug products for parenteral administration to be "practically free" or "essentially free" of visible particles, respectively. Both terms have been used interchangeably and acknowledge the probabilistic nature of visual particle inspection. The probability of seeing a particle in a drug product container varies according to the size and nature of the particles as well as container and inspection conditions. Therefore, the term "without visible particles" can be highly misleading in the context of what is practically achievable. This may lead to differences in understanding between industry practitioners and regulatory agencies. Is this term intended to mean "zero particles", or is there any intention to distinguish between particle type such as "zero extraneous visible particles" or "zero proteinaceous particles"? Furthermore, how can "zero" particles as a criterion for release testing be reconciled with "practically free from particles" as stated in the definition and a low, justified level of proteinaceous particles after production?The purpose of this position paper is to review best practices in the industry in terms of visual inspection process and associated operator training, quality control sampling, testing, and setting acceptance criteria corresponding to "practically free of visible particles" and providing considerations when visible proteinaceous particles are deemed unavoidable. It also provides a brief overview of visible particle characterization and gives perspectives on patient safety. This position paper applies to biotechnology-derived drug products including monoclonal antibodies in late-phase development to licensed products. In the 2011 monoclonal antibody monograph revision, European Pharmacopoeia experts acknowledged that protein products may also contain proteinaceous particles at release or that protein particles may form during storage. Indeed, industry experience has demonstrated that therapeutic proteins such as monoclonal antibodies can exhibit a propensity for self-association leading to the formation of aggregates that range in size from nanometres (oligomers) to microns (subvisible and visible particles). As a result, the requirement for drug product appearance for monoclonal antibodies was changed from "without visible particles" to "without visible particles unless otherwise authorised or justified". In our view, "practically free from particles" should be considered a suitable acceptance criterion for injectable biotechnology and small-molecule products, as long as appropriately defined. Furthermore, we argue that visual inspection is a suitable quality control release test and that "practically free from particles" is a suitable specification when adequately described. © PDA, Inc. 2016.

Extension of the XGC code for global gyrokinetic simulations in stellarator geometry

NASA Astrophysics Data System (ADS)

Cole, Michael; Moritaka, Toseo; White, Roscoe; Hager, Robert; Ku, Seung-Hoe; Chang, Choong-Seock

2017-10-01

In this work, the total-f, gyrokinetic particle-in-cell code XGC is extended to treat stellarator geometries. Improvements to meshing tools and the code itself have enabled the first physics studies, including single particle tracing and flux surface mapping in the magnetic geometry of the heliotron LHD and quasi-isodynamic stellarator Wendelstein 7-X. These have provided the first successful test cases for our approach. XGC is uniquely placed to model the complex edge physics of stellarators. A roadmap to such a global confinement modeling capability will be presented. Single particle studies will include the physics of energetic particles' global stochastic motions and their effect on confinement. Good confinement of energetic particles is vital for a successful stellarator reactor design. These results can be compared in the core region with those of other codes, such as ORBIT3d. In subsequent work, neoclassical transport and turbulence can then be considered and compared to results from codes such as EUTERPE and GENE. After sufficient verification in the core region, XGC will move into the stellarator edge region including the material wall and neutral particle recycling.

Heliophysics: Space Storms and Radiation: Causes and Effects

NASA Astrophysics Data System (ADS)

Schrijver, Carolus J.; Siscoe, George L.

2010-05-01

Preface; 1. Perspective on heliophysics George L. Siscoe and Carolus J. Schrijver; 2. Introduction to space storms and radiation Sten Odenwald; 3. In-situ detection of energetic particles George Gloeckler; 4. Radiative signatures of energetic particles Tim Bastian; 5. Observations of solar and stellar eruptions, flares, and jets Hugh Hudson; 6. Models of coronal mass ejections and flares Terry Forbes; 7. Shocks in heliophysics Merav Opher; 8. Particle acceleration in shocks Dietmar Krauss-Varban; 9. Energetic particle transport Joe Giacalone; 10. Energy conversion in planetary magnetospheres Vytenis Vasyliunas; 11. Energization of trapped particles Janet Green; 12. Flares, CMEs, and atmospheric responses Tim Fuller-Rowell and Stanley C. Solomon; 13. Energetic particles and manned spaceflight 358 Stephen Guetersloh and Neal Zapp; 14. Energetic particles and technology Alan Tribble; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

Heliophysics: Space Storms and Radiation: Causes and Effects

NASA Astrophysics Data System (ADS)

Schrijver, Carolus J.; Siscoe, George L.

2012-01-01

Preface; 1. Perspective on heliophysics George L. Siscoe and Carolus J. Schrijver; 2. Introduction to space storms and radiation Sten Odenwald; 3. In-situ detection of energetic particles George Gloeckler; 4. Radiative signatures of energetic particles Tim Bastian; 5. Observations of solar and stellar eruptions, flares, and jets Hugh Hudson; 6. Models of coronal mass ejections and flares Terry Forbes; 7. Shocks in heliophysics Merav Opher; 8. Particle acceleration in shocks Dietmar Krauss-Varban; 9. Energetic particle transport Joe Giacalone; 10. Energy conversion in planetary magnetospheres Vytenis Vasyliūnas; 11. Energization of trapped particles Janet Green; 12. Flares, CMEs, and atmospheric responses Tim Fuller-Rowell and Stanley C. Solomon; 13. Energetic particles and manned spaceflight 358 Stephen Guetersloh and Neal Zapp; 14. Energetic particles and technology Alan Tribble; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

How does money memorize social interactions? Understanding time-homogeneity in monetary systems

NASA Astrophysics Data System (ADS)

Braun, Dieter; Schmitt, Matthias; Schacker, Andreas

2013-03-01

Understanding how money shapes and memorizes our social interactions is central to modern life. There are many schools of thought on as to how monetary systems contribute to crises or boom/bust cycles and how monetary policy can try to avert them. We find that statistical physics gives a refreshing perspective. We analyze how credit mechanisms introduce non-locality and time-heterogeneity to the monetary memory. Motivated by an analogy to particle physics, locality and time-homogeneity can be imposed to monetary systems. As a result, a full reserve banking system is complemented with a bi-currency system of non-bank assets (``money'') and bank assets (``antimoney''). Payment can either be made by passing on money or by receiving antimoney. As a result, a free floating exchange rate between non-bank assets and bank assets is established. Interestingly, this monetary memory allows for credit creation by the simultaneous transfer of money and antimoney at a negotiated exchange rate. We analyze this novel mechanism of liquidity transfer in a model of random social interactions, yielding analytical results for all relevant distributions and the price of liquidity under the conditions of a fully transparent credit market.

Cultural Perspectives on Teacher Education

NASA Astrophysics Data System (ADS)

Muhoro, Peter; Cochran, Geraldine; Gonzalez, Victor; Rockward, Willie; Sunda-Meya, Anderson; Incera, Vivian

2012-02-01

Populations that are underrepresented in physics generally are even more severely underrepresented among US physics teachers. Based on national data from the American Institute of Physics (AIP), 95% of physics teachers are White/non-Hispanic, about 1.5% are Hispanic, and approximately another 1.5% African-American. While 25% of our nation's African-American and Hispanic students now take physics in high school, they are very unlikely to have a role model, of similar race and ethnicity, teaching their physics classes. PhysTEC is making an effort to find and disseminate successful models for attracting more underrepresented minority students to high school physics teaching. This panel discussion, focusing on cultural perspectives on teacher education, will feature faculty from Minority Serving Institutions, which educate almost 60% of underrepresented minorities who get college degrees in the US, and individuals who have taught high school physics in areas with a dense minority population.

Physics in perspective: Recommendations and program emphases

NASA Technical Reports Server (NTRS)

1972-01-01

Exerpted material from Physics in Perspective, Vol. 1, is presented on recommendations, priorities, and program emphases. The major recommendations are addressed to the Federal Government and support agencies, the physics community, and the educational community, including precollege, undergraduate, and graduate sectors. Approaches to the questions involved in establishing scientific priorities are discussed, and an approach is evolved which is based on the jury rating application of certain criteria to the program elements of a subfield. The question of national support level for the physics enterprise is also considered, and contingency alternatives are suggested such that whatever the level of available support, it may be used with maximum effectiveness.

Shadows constructing a relationship between light and color pigments by physical and mathematical perspectives

NASA Astrophysics Data System (ADS)

Yurumezoglu, Kemal; Karabey, Burak; Yigit Koyunkaya, Melike

2017-03-01

Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the linear dispersion of light. This paper focuses on progressing the understanding of shadows from physical and mathematical perspectives. A significant relationship between light and color pigments is demonstrated with the help of the concept of sets. This integration of physical and mathematical reasoning not only manages an operational approach to the concept of shadows, it also outputs a model that can be used in science, technology, engineering and mathematics (STEM) curricula by providing a concrete and physical example for abstract concept of the empty set.

Identity of Particles and Continuum Hypothesis

NASA Astrophysics Data System (ADS)

Berezin, Alexander A.

2001-04-01

Why all electrons are the same? Unlike other objects, particles and atoms (same isotopes) are forbidden to have individuality or personal history (or reveal their hidden variables, even if they do have them). Or at least, what we commonly call physics so far was unable to disprove particle's sameness (Berezin and Nakhmanson, Physics Essays, 1990). Consider two opposing hypotheses: (A) particles are indeed absolutely same, or (B) they do have individuality, but it is beyond our capacity to demonstrate. This dilemma sounds akin to undecidability of Continuum Hypothesis of existence (or not) of intermediate cardinalities between integers and reals (P.Cohen). Both yes and no of it are true. Thus, (alleged) sameness of electrons and atoms may be a physical translation (embodiment) of this fundamental Goedelian undecidability. Experiments unlikely to help: even if we find that all electrons are same within 30 decimal digits, could their masses (or charges) still differ in100-th digit? Within (B) personalized informationally rich (infinitely rich?) digital tails (starting at, say, 100-th decimal) may carry individual record of each particle history. Within (A) parameters (m, q) are indeed exactly same in all digits and their sameness is based on some inherent (meta)physical principle akin to Platonism or Eddington-type numerology.

Combustion Of Porous Graphite Particles In Oxygen Enriched Air

NASA Technical Reports Server (NTRS)

Delisle, Andrew J.; Miller, Fletcher J.; Chelliah, Harsha K.

2003-01-01

Combustion of solid fuel particles has many important applications, including power generation and space propulsion systems. The current models available for describing the combustion process of these particles, especially porous solid particles, include various simplifying approximations. One of the most limiting approximations is the lumping of the physical properties of the porous fuel with the heterogeneous chemical reaction rate constants [1]. The primary objective of the present work is to develop a rigorous modeling approach that could decouple such physical and chemical effects from the global heterogeneous reaction rates. For the purpose of validating this model, experiments with porous graphite particles of varying sizes and porosity are being performed under normal and micro gravity.

Energy peaks: A high energy physics outlook

NASA Astrophysics Data System (ADS)

Franceschini, Roberto

2017-12-01

Energy distributions of decay products carry information on the kinematics of the decay in ways that are at the same time straightforward and quite hidden. I will review these properties and discuss their early historical applications, as well as more recent ones in the context of (i) methods for the measurement of masses of new physics particle with semi-invisible decays, (ii) the characterization of Dark Matter particles produced at colliders, (iii) precision mass measurements of Standard Model particles, in particular of the top quark. Finally, I will give an outlook of further developments and applications of energy peak method for high energy physics at colliders and beyond.

Shoichi Sakata: His Life and Physics ---Collections of Materials in Sakata Memorial Archival Library---

NASA Astrophysics Data System (ADS)

Tanabashi, M.

Shoichi Sakata and his Nagoya School made a lot of important achievements at the predawn of the particle physics revolution. The ``two-meson'' theory (introduction of the second generation leptons), the ``C-meson theory'' (a theory which inspired Tomonaga's renormalization theory), the ``Sakata model'' (a precursor to the quark model), and the ``Maki-Nakagawa-Sakata'' theory on the neutrino mixings are among them. These outputs are now regarded as essential ingredients in modern particle physics. Sakata also took his leadership in setting up democratic administration system in his theoretical particle physics group (E-ken). It was this democratic atmosphere in which many excellent physicists were brought up as Sakata's diciples. In this talk, I introduce Sakata and his achievements in physics, showing various materials archived in the Sakata Memorial Archival Library (SMAL), an archival repository of primary material showing Sakata's activities. These SMAL documents vividly show Sakata's way of thinking in his approach to the new physics.

USPAS | U.S. Particle Accelerator School

Science.gov Websites

U.S. Particle Accelerator School U.S. Particle Accelerator School U.S. Particle Accelerator School U.S. Particle Accelerator School Education in Beam Physics and Accelerator Technology Home About About University Credits Joint International Accelerator School University-Style Programs Symposium-Style Programs

Physical and biological studies of coal and oil fly ash.

PubMed Central

Fisher, G L; McNeill, K L; Prentice, B A; McFarland, A R

1983-01-01

Studies were performed to compare the physical and chemical characteristics and the in vitro macrophage cytotoxicity of oil and coal fly ash. Sampling methodology was developed to collect size-fractionated particulate matter from the smokestack of either a coal-fired or an oil-fired power plant. Morphological studies demonstrated particle heterogeneity, although most coal fly ash particles appeared to be spherical. Oil fly ash contained two major morphologies; nonopaque amorphous particles and opaque amorphous particles. Elemental analysis indicates that the coal ash is predominantly composed of aluminosilicate particles, while the oil ash is predominantly inorganic sulfates and carbonaceous particles. In vitro macrophage assays demonstrate that the finest coal fly ash particles are the most cytotoxic; the cytotoxicity is significantly less than that of alpha-quartz, the positive control particle. In contrast, the oil fly ash particles are more cytotoxic than quartz. The cytotoxicity of oil fly ash is due to soluble components, possibly vanadium salts. Images FIGURE 2. A FIGURE 2. B FIGURE 2. C FIGURE 2. D PMID:6641653

A demonstration of particle duality of light

NASA Astrophysics Data System (ADS)

Jiang, Haili; Liu, Zhihai; Sun, Qiuhua; Zhao, Yancheng

2017-08-01

The need of understanding and teaching about wave-particle duality if light with gets more and more apparent in the background of the attention of modern physics. As early as the beginning of twentieth Century, Einstein dared to "deny" the development of a very perfect light electromagnetic theory, so that the quantum of light can be developed. In 1924, De Broglie put forward wave-particle duality if light to other micro particles and the concept of matter wave, pointed out that all micro particle has wave-particle duality. This is a very abstract concept for students, most college physics teaching all lack of demonstration about particle duality of light. The present article aims to contribute to demonstrate the wave-particle duality of light at the same time using a simple way based on fiber optical tweezers. It is hoped that useful lesson can be absorbed so that students can deepen the understanding of the particle and wave properties of light. To complement the demonstration experiment for this attribute light has momentum.

Multi-Parameter Scattering Sensor and Methods

NASA Technical Reports Server (NTRS)

Greenberg, Paul S. (Inventor); Fischer, David G. (Inventor)

2016-01-01

Methods, detectors and systems detect particles and/or measure particle properties. According to one embodiment, a detector for detecting particles comprises: a sensor for receiving radiation scattered by an ensemble of particles; and a processor for determining a physical parameter for the detector, or an optimal detection angle or a bound for an optimal detection angle, for measuring at least one moment or integrated moment of the ensemble of particles, the physical parameter, or detection angle, or detection angle bound being determined based on one or more of properties (a) and/or (b) and/or (c) and/or (d) or ranges for one or more of properties (a) and/or (b) and/or (c) and/or (d), wherein (a)-(d) are the following: (a) is a wavelength of light incident on the particles, (b) is a count median diameter or other characteristic size parameter of the particle size distribution, (c) is a standard deviation or other characteristic width parameter of the particle size distribution, and (d) is a refractive index of particles.

Shock Interaction of Metal Particles in Condensed Explosive Detonation

NASA Astrophysics Data System (ADS)

Ripley, Robert; Zhang, Fan; Lien, Fue-Sang

2005-07-01

For detonation propagation in a condensed explosive with metal particles, a macro-scale physical model describing the momentum transfer between the explosive and particles has yet to be completely established. Previous 1D and 2D meso-scale modeling studies indicated that significant momentum transfer from the explosive to the particles occurs as the leading shock front crosses the particles, thus influencing the initiation and detonation structure. In this work, 3D meso-scale modeling is conducted to further study the two-phase momentum transfer during the shock diffraction and subsequent detonation in liquid nitromethane containing packed metal particles. Detonation of the condensed explosive is computed using an Arrhenius reaction model and a hybrid EOS model that combines the Mie-Gruneisen equation for reactants and the JWL equation for products. The compressible particles are modeled using the Tait EOS, where the material strength is negligible. The effect of particle packing configuration and inter-particle spacing is shown by parametric studies. Finally, a physical description of the momentum transfer is discussed.

Magnetic particle motions within living cells. Physical theory and techniques.

PubMed Central

Valberg, P A; Butler, J P

1987-01-01

Body tissues are not ferromagnetic, but ferromagnetic particles can be present as contaminants or as probes in the lungs and in other organs. The magnetic domains of these particles can be aligned by momentary application of an external magnetic field; the magnitude and time course of the resultant remanent field depend on the quantity of magnetic material and the degree of particle motion. The interpretation of magnetometric data requires an understanding of particle magnetization, agglomeration, random motion, and both rotation and translation in response to magnetic fields. We present physical principles relevant to magnetometry and suggest models for intracellular particle motion driven by thermal, elastic, or cellular forces. The design principles of instrumentation for magnetizing intracellular particles and for detecting weak remanent magnetic fields are described. Such magnetic measurements can be used for noninvasive studies of particle clearance from the body or of particle motion within body tissues and cells. Assumptions inherent to this experimental approach and possible sources of artifact are considered and evaluated. PMID:3676435

Adsorption-desorption kinetics of soft particles onto surfaces

NASA Astrophysics Data System (ADS)

Osberg, Brendan; Gerland, Ulrich

A broad range of physical, chemical, and biological systems feature processes in which particles randomly adsorb on a substrate. Theoretical models usually assume ``hard'' (mutually impenetrable) particles, but in soft matter physics the adsorbing particles can be effectively compressible, implying ``soft'' interaction potentials. We recently studied the kinetics of such soft particles adsorbing onto one-dimensional substrates, identifying three novel phenomena: (i) a gradual density increase, or ''cramming'', replaces the usual jamming behavior of hard particles, (ii) a density overshoot, can occur (only for soft particles) on a time scale set by the desorption rate, and (iii) relaxation rates of soft particles increase with particle size (on a lattice), while hard particles show the opposite trend. The latter occurs since unjamming requires desorption and many-bodied reorganization to equilibrate -a process that is generally very slow. Here we extend this analysis to a two-dimensional substrate, focusing on the question of whether the adsorption-desorption kinetics of particles in two dimensions is similarly enriched by the introduction of soft interactions. Application to experiments, for example the adsorption of fibrinogen on two-dimensional surfaces, will be discussed.

Phloem physics: mechanisms, constraints, and perspectives.

PubMed

Jensen, Kaare H

2018-04-13

Plants have evolved specialized vascular tissues for the distribution of energy, water, nutrients, and for communication. The phloem transports sugars from photosynthetic source regions (e.g. mature leaves) to sugar sinks (e.g. developing tissues such as buds, flowers, roots). Moreover, chemical signals such as hormones, RNAs and proteins also move in the phloem. Basic physical processes strongly limit phloem anatomy and function. This paper provides an overview of recent research and perspectives on phloem biomechanics and the physical constraints relevant to sugar transport in plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Jet-images — deep learning edition

DOE PAGES

de Oliveira, Luke; Kagan, Michael; Mackey, Lester; ...

2016-07-13

Building on the notion of a particle physics detector as a camera and the collimated streams of high energy particles, or jets, it measures as an image, we investigate the potential of machine learning techniques based on deep learning architectures to identify highly boosted W bosons. Modern deep learning algorithms trained on jet images can out-perform standard physically-motivated feature driven approaches to jet tagging. We develop techniques for visualizing how these features are learned by the network and what additional information is used to improve performance. Finally, this interplay between physically-motivated feature driven tools and supervised learning algorithms is generalmore » and can be used to significantly increase the sensitivity to discover new particles and new forces, and gain a deeper understanding of the physics within jets.« less

Jet-images — deep learning edition

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Oliveira, Luke; Kagan, Michael; Mackey, Lester

Building on the notion of a particle physics detector as a camera and the collimated streams of high energy particles, or jets, it measures as an image, we investigate the potential of machine learning techniques based on deep learning architectures to identify highly boosted W bosons. Modern deep learning algorithms trained on jet images can out-perform standard physically-motivated feature driven approaches to jet tagging. We develop techniques for visualizing how these features are learned by the network and what additional information is used to improve performance. Finally, this interplay between physically-motivated feature driven tools and supervised learning algorithms is generalmore » and can be used to significantly increase the sensitivity to discover new particles and new forces, and gain a deeper understanding of the physics within jets.« less

Particle Physics in High School: A Diagnose Study

PubMed Central

Solbes, Jordi

2016-01-01

The science learning process improves when the contents are connected to students’ lives. Particle physics has had a great impact in our society in the last years and has changed the theoretical picture about matter fundamental dynamics. Thus, we think that academic contents about matter components and interactions should be updated. With this study we aim to characterize the level of knowledge of high school students about this topic. We built a test with questions about classical atomic models, particle physics, recent discoveries, social implications and students opinions about it. Contrary to our first suspicion, students’ answers show a high variability. They have new physics ideas and show a great interest towards modern concepts. We suggest including an updated view of this topic as part of the curriculum. PMID:27253377

Particle Physics in High School: A Diagnose Study.

PubMed

Tuzón, Paula; Solbes, Jordi

2016-01-01

The science learning process improves when the contents are connected to students' lives. Particle physics has had a great impact in our society in the last years and has changed the theoretical picture about matter fundamental dynamics. Thus, we think that academic contents about matter components and interactions should be updated. With this study we aim to characterize the level of knowledge of high school students about this topic. We built a test with questions about classical atomic models, particle physics, recent discoveries, social implications and students opinions about it. Contrary to our first suspicion, students' answers show a high variability. They have new physics ideas and show a great interest towards modern concepts. We suggest including an updated view of this topic as part of the curriculum.

Multi-Level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory

ERIC Educational Resources Information Center

Vieira, Rodrigo Drumond; Kelly, Gregory J.

2014-01-01

In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective,…

Cosmology and particle physics

NASA Astrophysics Data System (ADS)

Barrow, J. D.

A brief overview is given of recent work that integrates cosmology and particle physics. The observational data regarding the abundance of matter and radiation in the universe is described. The manner in which the cosmological survival density of stable massive particles can be calculated is discussed along with the process of cosmological nucleosynthesis. Several applications of these general arguments are given with reference to the survival density of nucleons, neutrinos and unconfined fractionally charge particles. The use of nucleosynthesis to limit the number of lepton generations is described together with the implications of a small neutrino mass for the origin of galaxies and clusters.

Tamper resistant magnetic stripes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naylor, R.B.; Sharp, D.J.

1999-11-09

This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180{degree} opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40 C, is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable timemore » limits.« less

Particle Detectors Subatomic Bomb Squad

ScienceCinema

Lincoln, Don

2018-01-16

The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

Tamper resistant magnetic stripes

DOEpatents

Naylor, Richard Brian; Sharp, Donald J.

1999-01-01

This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.

100 years of elementary particles [Beam Line, vol. 27, issue 1, Spring 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pais, Abraham; Weinberg, Steven; Quigg, Chris

1997-04-01

This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

100 years of Elementary Particles [Beam Line, vol. 27, issue 1, Spring 1997

DOE R&D Accomplishments Database

Pais, Abraham; Weinberg, Steven; Quigg, Chris; Riordan, Michael; Panofsky, Wolfgang K. H.; Trimble, Virginia

1997-04-01

This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

Physics Teachers' Views on Their Initial Teacher Education

ERIC Educational Resources Information Center

Buabeng, Isaac; Conner, Lindsey; Winter, David

2016-01-01

This paper explores New Zealand (NZ) physics teachers' and physics educators' views about Initial Teacher Education (ITE). Perspectives of physics teachers nationally indicated that in general, teachers considered themselves not well-prepared in some content areas including electronics, modern physics, and atomic and nuclear physics. This may be…

Characterization of the Physical Stability of a Lyophilized IgG1 mAb After Accelerated Shipping-like Stress

PubMed Central

Telikepalli, Srivalli; Kumru, Ozan S.; Kim, Jae Hyun; Joshi, Sangeeta B.; O'Berry, Kristin B.; Blake-Haskins, Angela W.; Perkins, Melissa D.; Middaugh, C. Russell; Volkin, David B.

2014-01-01

Upon exposure to shaking stress, an IgG1 mAb formulation in both liquid and lyophilized state formed subvisible particles. Since freeze-drying is expected to minimize protein physical instability under these conditions, the extent and nature of aggregate formation in the lyophilized preparation was examined using a variety of particle characterization techniques. The effect of formulation variables such as residual moisture content, reconstitution rate, and reconstitution medium were examined. Upon reconstitution of shake-stressed lyophilized mAb, differences in protein particle size and number were observed by Microflow Digital Imaging (MFI), with the reconstitution medium having the largest impact. Shake-stress had minor effects on the structure of protein within the particles as shown by SDS-PAGE and FTIR analysis. The lyophilized mAb was shake-stressed to different extents and stored for 3 months at different temperatures. Both extent of cake collapse and storage temperature affected the physical stability of the shake-stressed lyophilized mAb upon subsequent storage. These findings demonstrate that physical degradation upon shaking of a lyophilized IgG1 mAb formulation includes not only cake breakage, but also results in an increase in subvisible particles and turbidity upon reconstitution. The shaking-induced cake breakage of the lyophilized IgG1 mAb formulation also resulted in decreased physical stability upon storage. PMID:25522000

The Discovery of Subatomic Particles Revised Edition

NASA Astrophysics Data System (ADS)

Weinberg, Steven

2003-09-01

This commentary on the discovery of the atom's constituents provides an historical account of key events in the physics of the twentieth century that led to the discoveries of the electron, proton and neutron. Steven Weinberg introduces the fundamentals of classical physics that played crucial roles in these discoveries. Connections are shown throughout the book between the historic discoveries of subatomic particles and contemporary research at the frontiers of physics, including the most current discoveries of new elementary particles. Steven Weinberg was Higgins Professor of Physics at Harvard before moving to The University of Texas at Austin, where he founded its Theory Group. At Texas he holds the Josey Regental Chair of Science and is a member of the Physics and Astronomy Departments. His research has spanned a broad range of topics in quantum field theory, elementary particle physics, and cosmology, and has been honored with numerous awards, including the Nobel Prize in Physics, the National Medal of Science, the Heinemann Prize in Mathematical Physics, the Cresson Medal of the Franklin Institute, the Madison Medal of Princeton University, and the Oppenheimer Prize. In addition to the well-known treatise, Gravitation and Cosmololgy, he has written several books for general readers, including the prize-winning The First Three Minutes (now translated into 22 foreign languages), and most recently Dreams of a Final Theory (Pantheon Books, 1993). He has also written a textbook The Quantum Theory of Fields, Vol.I, Vol. II, and Vol. III (Cambridge).

Physical-geometric optics method for large size faceted particles.

PubMed

Sun, Bingqiang; Yang, Ping; Kattawar, George W; Zhang, Xiaodong

2017-10-02

A new physical-geometric optics method is developed to compute the single-scattering properties of faceted particles. It incorporates a general absorption vector to accurately account for inhomogeneous wave effects, and subsequently yields the relevant analytical formulas effective and computationally efficient for absorptive scattering particles. A bundle of rays incident on a certain facet can be traced as a single beam. For a beam incident on multiple facets, a systematic beam-splitting technique based on computer graphics is used to split the original beam into several sub-beams so that each sub-beam is incident only on an individual facet. The new beam-splitting technique significantly reduces the computational burden. The present physical-geometric optics method can be generalized to arbitrary faceted particles with either convex or concave shapes and with a homogeneous or an inhomogeneous (e.g., a particle with a core) composition. The single-scattering properties of irregular convex homogeneous and inhomogeneous hexahedra are simulated and compared to their counterparts from two other methods including a numerically rigorous method.

Sixfold improved single particle measurement of the magnetic moment of the antiproton.

PubMed

Nagahama, H; Smorra, C; Sellner, S; Harrington, J; Higuchi, T; Borchert, M J; Tanaka, T; Besirli, M; Mooser, A; Schneider, G; Blaum, K; Matsuda, Y; Ospelkaus, C; Quint, W; Walz, J; Yamazaki, Y; Ulmer, S

2017-01-18

Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value /2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement g p /2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20.

Sixfold improved single particle measurement of the magnetic moment of the antiproton

PubMed Central

Nagahama, H.; Smorra, C.; Sellner, S.; Harrington, J.; Higuchi, T.; Borchert, M. J.; Tanaka, T.; Besirli, M.; Mooser, A.; Schneider, G.; Blaum, K.; Matsuda, Y.; Ospelkaus, C.; Quint, W.; Walz, J.; Yamazaki, Y.; Ulmer, S.

2017-01-01

Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value /2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement gp/2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20. PMID:28098156

Foundations of modelling of nonequilibrium low-temperature plasmas

NASA Astrophysics Data System (ADS)

Alves, L. L.; Bogaerts, A.; Guerra, V.; Turner, M. M.

2018-02-01

This work explains the need for plasma models, introduces arguments for choosing the type of model that better fits the purpose of each study, and presents the basics of the most common nonequilibrium low-temperature plasma models and the information available from each one, along with an extensive list of references for complementary in-depth reading. The paper presents the following models, organised according to the level of multi-dimensional description of the plasma: kinetic models, based on either a statistical particle-in-cell/Monte-Carlo approach or the solution to the Boltzmann equation (in the latter case, special focus is given to the description of the electron kinetics); multi-fluid models, based on the solution to the hydrodynamic equations; global (spatially-average) models, based on the solution to the particle and energy rate-balance equations for the main plasma species, usually including a very complete reaction chemistry; mesoscopic models for plasma-surface interaction, adopting either a deterministic approach or a stochastic dynamical Monte-Carlo approach. For each plasma model, the paper puts forward the physics context, introduces the fundamental equations, presents advantages and limitations, also from a numerical perspective, and illustrates its application with some examples. Whenever pertinent, the interconnection between models is also discussed, in view of multi-scale hybrid approaches.

Magnetic fluid hyperthermia (MFH): Cancer treatment with AC magnetic field induced excitation of biocompatible superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Jordan, Andreas; Scholz, Regina; Wust, Peter; Fähling, Horst; Felix, Roland

1999-07-01

The story of hyperthermia with small particles in AC magnetic fields started in the late 1950s, but most of the studies were unfortunately conducted with inadequate animal systems, inexact thermometry and poor AC magnetic field parameters, so that any clinical implication was far behind the horizon. More than three decades later, it was found, that colloidal dispersions of superparamagnetic (subdomain) iron oxide nanoparticles exhibit an extraordinary specific absorption rate (SAR [ W/ g]), which is much higher at clinically tolerable H 0 f combinations in comparison to hysteresis heating of larger multidomain particles. This was the renaissance of a cancer treatment method, which has gained more and more attention in the last few years. Due to the increasing number of randomized clinical trials preferentially in Europe with conventional E-field hyperthermia systems, the general medical and physical experience in hyperthermia application is also rapidly growing. Taking this increasing clinical experience carefully into account together with the huge amount of new biological data on heat response of cells and tissues, the approach of magnetic fluid hyperthermia (MFH) is nowadays more promising than ever before. The present contribution reviews the current state of the art and some of the future perspectives supported by advanced methods of the so-called nanotechnology.

Energetic Particles in the Inner Heliosphere

NASA Astrophysics Data System (ADS)

Malandraki, Olga

2016-07-01

Solar Energetic Particle (SEP) events are a key ingredient of Solar-Terrestrial Physics both for fundamental research and space weather applications. SEP events are the defining component of solar radiation storms, contribute to radio blackouts in polar regions and are related to many of the fastest Coronal Mass Ejections (CMEs) driving major geomagnetic storms. In addition to CMEs, SEPs are also related to flares. In this work, the current state of knowledge on the SEP field will be reviewed. Key issues to be covered and discussed include: the current understanding of the origin, acceleration and transport processes of SEPs at the Sun and in the inner heliosphere, lessons learned from multi-spacecraft SEP observations, statistical quantification of the comparison of solar events and SEP events of the current solar cycle 24 with previous solar cycles, causes of the solar-cycle variations in SEP fluencies and composition, theoretical work and current SEP acceleration models. Furthermore, the outstanding issues that constitute a knowledge gap in the field will be presented and discussed, as well as future directions and expected advances from the observational and modeling perspective, also in view of the unique observations provided by the upcoming Solar Orbiter and Solar Probe Plus missions. Acknowledgement: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

Electrical behavior of natural manganese dioxide (NMD)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorgulho, H.F.; Fernandes, R.Z.D.; Pernaut, J.M.

NMD samples from Brazil have been submitted to magnetic and particle size separations and characterized by X-ray diffraction and fluorescence and thermogravimetric analyses. Results showed that simple physical treatments can lead to more than 60% enriched MnO{sub 2} materials which could satisfy some electrochemical applications. The electrical properties of the samples conditioned as pressed pellets have been investigated by four-points direct current probe and impedance spectroscopy, varying the conditions of preparation and measurement. It is proposed that the higher frequency impedance is equivalent to the intrinsic electronic resistance of the MnO{sub 2} phases while at lower frequencies occurs an interphasemore » charge separation coupled with a possible ionic transport. The corresponding contact resistance depends on the particle size distribution of the material, the compactation pressure of pellets and the iron content of the materials. The interphase dielectric relaxation does not behave ideally; the depression of the impedance semicircles as shown in the Nyquist plane is assumed to be related to the roughness of the bulk interfaces. Recent developments have shown the possibility of using manganese oxides as reversible electrodes for battery or supercapacitor applications for electrical vehicle. In these perspectives it is important to study the electrical and electrochemical properties of NMD in order to estimate its suitability for this kind of applications.« less

Synthesis and mechanical behavior of β-tricalcium phosphate/titania composites addressed to regeneration of long bone segments.

PubMed

Sprio, Simone; Guicciardi, Stefano; Dapporto, Massimiliano; Melandri, Cesare; Tampieri, Anna

2013-01-01

Bioactive tricalcium phosphate/titania ceramic composites were synthesized by pressureless air sintering of mixed hydroxyapatite and titania (TiO2) powders. The sintering process was optimized to achieve dense ceramic bodies consisting in a bioactive/bioresorbable matrix (β-tricalcium phosphate) reinforced with defined amounts of sub-micron sized titania particles. Extensive chemico-physical and mechanical characterization was carried out on the resulting composites, which displayed values of flexural strength, fracture toughness and elastic modulus in the range or above the typical ranges of values manifested by human cortical bone. It was shown that titania particles provided a toughening effect to the calcium-phosphate matrix and a reinforcement in fracture strength, in comparison with sintered hydroxyapatite bodies characterized by similar relative density. The characteristics of the resulting composites, i.e. bioactivity/bioresorbability and ability of manifesting biomimetic mechanical behavior, are features that can promote processes of bone regeneration in load-bearing sites. Hence, in the perspective of developing porous bone scaffolds with high bioactivity and improved biomechanical behavior, TCP/TiO2 composites with controlled composition can be considered as very promising biomaterials for application in a field of orthopedics where no acceptable clinical solutions still exist. Copyright © 2012 Elsevier Ltd. All rights reserved.

CaloCube: A new-concept calorimeter for the detection of high-energy cosmic rays in space

NASA Astrophysics Data System (ADS)

Vannuccini, E.; Adriani, O.; Agnesi, A.; Albergo, S.; Auditore, L.; Basti, A.; Berti, E.; Bigongiari, G.; Bonechi, L.; Bonechi, S.; Bongi, M.; Bonvicini, V.; Bottai, S.; Brogi, P.; Carotenuto, G.; Castellini, G.; Cattaneo, P. W.; D'Alessandro, R.; Detti, S.; Fasoli, M.; Finetti, N.; Lenzi, P.; Maestro, P.; Marrocchesi, P. S.; Miritello, M.; Mori, N.; Orzan, G.; Olmi, M.; Pacini, L.; Papini, P.; Pellegriti, M. G.; Pirzio, F.; Rappoldi, A.; Ricciarini, S.; Spillantini, P.; Starodubtsev, O.; Stolzi, F.; Suh, J. E.; Sulaj, A.; Tiberio, A.; Tricomi, A.; Trifiro, A.; Trimarchi, M.; Vedda, A.; Zampa, G.; Zampa, N.; Zerbo, B.

2017-02-01

The direct observation of high-energy cosmic rays, up to the PeV region, will increasingly rely on highly performing calorimeters, and the physics performance will be primarily determined by their geometrical acceptance and energy resolution. Thus, it is extremely important to optimize their geometrical design, granularity, and absorption depth, with respect to the total mass of the apparatus, which is among the most important constraints for a space mission. Calocube is a homogeneous calorimeter whose basic geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic scintillating crystals. This design forms the basis of a three-year R &D activity which has been approved and financed by INFN. A comparative study of different scintillating materials has been performed. Optimal values for the size of the crystals and spacing among them have been studied. Different geometries, besides the cubic one, and the possibility to implement dual-readout techniques have been investigated. A prototype, instrumented with CsI(Tl) cubic crystals, has been constructed and tested with particle beams. An overview of the obtained results will be presented and the perspectives for future space experiments will be discussed.

Inclusion understood from the perspectives of children with disability.

PubMed

Spencer-Cavaliere, Nancy; Watkinson, E Jane

2010-10-01

This study explored the perspectives of children with disabilities regarding the concept of inclusion in physical activity. Participants were children (two girls, nine boys, Mage = 10 years, five months, age range: 8-12 years) with disabilities, including cerebral palsy, fine and gross motor delays, developmental coordination disorder, muscular dystrophy, nemaline myopathy, brachial plexus injury, and severe asthma. Children's perspectives on inclusion in physical activity (e.g., sports, games, and play) were explored through semistructured interviews. Interviews were digitally audio taped and transcribed verbatim. Data were analyzed through content analysis. Three themes emerged from the data: gaining entry to play, feeling like a legitimate participant, and having friends. These themes were associated with feeling included to varying degrees in sports, games, and play. In essence, it was the actions of others that were the prominent features identified by children that contributed to feeling more or less included in physical activity contexts. These results are discussed in relation to inclusion in physical education, recreation, and unstructured free play.

History of the Bevatron

ScienceCinema

None

2017-12-09

This 1993 documentary chronicles the Bevatron at Berkeley Lab. During its operation from 1954 until 1993, the Bevatron was among the world's leading particle accelerators, and during the 1950s and 1960s, four Nobel Prizes were awarded for work conducted in whole or in part there. The accelerator made major contributions in four distinct areas of research: high-energy particle physics, nuclear heavy-ion physics, medical research and therapy, and space-related studies of radiation damage and heavy particles in space.

RICH detectors: Analysis methods and their impact on physics

NASA Astrophysics Data System (ADS)

Križan, Peter

2017-12-01

The paper discusses the importance of particle identification in particle physics experiments, and reviews the impact of ring imaging Cherenkov (RICH) counters in experiments that are currently running, or are under construction. Several analysis methods are discussed that are needed to calibrate a RICH counter, and to align its components with the rest of the detector. Finally, methods are reviewed on how to employ the collected data to efficiently separate one particle species from the other.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

Meta-analysis inside and outside particle physics: two traditions that should converge?

PubMed

Baker, Rose D; Jackson, Dan

2013-06-01

The use of meta-analysis in medicine and epidemiology really took off in the 1970s. However, in high-energy physics, the Particle Data Group has been carrying out meta-analyses of measurements of particle masses and other properties since 1957. Curiously, there has been virtually no interaction between those working inside and outside particle physics. In this paper, we use statistical models to study two major differences in practice. The first is the usefulness of systematic errors, which physicists are now beginning to quote in addition to statistical errors. The second is whether it is better to treat heterogeneity by scaling up errors as do the Particle Data Group or by adding a random effect as does the rest of the community. Besides fitting models, we derive and use an exact test of the error-scaling hypothesis. We also discuss the other methodological differences between the two streams of meta-analysis. Our conclusion is that systematic errors are not currently very useful and that the conventional random effects model, as routinely used in meta-analysis, has a useful role to play in particle physics. The moral we draw for statisticians is that we should be more willing to explore 'grassroots' areas of statistical application, so that good statistical practice can flow both from and back to the statistical mainstream. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.

Lunar Regolith Simulant User's Guide

NASA Technical Reports Server (NTRS)

Schrader, C. M.; Rickman, D. L.; McLemore, C. A.; Fikes, J. C.

2010-01-01

Based on primary characteristics, currently or recently available lunar regolith simulants are discussed from the perspective of potential experimental uses. The characteristics used are inherent properties of the material rather than their responses to behavioral (geomechanical, physiochemical, etc.) tests. We define these inherent or primary properties to be particle composition, particle size distribution, particle shape distribution, and bulk density. Comparable information about lunar materials is also provided. It is strongly emphasized that anyone considering either choosing or using a simulant should contact one of the members of the simulant program listed at the end of this document.

Different Levels of the Meaning of Wave-Particle Duality and a Suspensive Perspective on the Interpretation of Quantum Theory

ERIC Educational Resources Information Center

Cheong, Yong Wook; Song, Jinwoong

2014-01-01

There is no consensus on the genuine meaning of wave-particle duality and the interpretation of quantum theory. How can we teach duality and quantum theory despite this lack of consensus? This study attempts to answer this question. This research argues that reality issues are at the core of both the endless debates concerning the interpretation…

A Vision of Nuclear and Particle Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery, Hugh E.

2016-08-01

This paper will consist of a selected, personal view of some of the issues associated with the intersections of nuclear and particle physics. As well as touching on the recent developments we will attempt to look at how those aspects of the subject might evolve over the next few years.

What is Supersymmetry?

ScienceCinema

Lincoln, Don

2018-01-16

In this video, Fermilab's Dr. Don Lincoln describes the principle of supersymmetry in an easy-to-understand way. A theory is supersymmetric if it treats forces and matter on an equal footing. While supersymmetry is an unproven idea, it is popular with particle physics researchers as a possible next step in particle physics.

Search for Hidden Particles: a new experiment proposal

NASA Astrophysics Data System (ADS)

De Lellis, G.

2015-08-01

Searches for new physics with accelerators are being performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. We propose a new experiment meant to search for very weakly coupled particles in the few GeV mass domain. The existence of such particles, foreseen in different models beyond the Standard Model, is largely unexplored from the experimental point of view. A beam dump facility, built at CERN in the north area, using 400 GeV protons is a copious factory of charmed hadrons and it could be used to probe the existence of such particles. The beam dump is also an ideal source of tau neutrinos, the less known particle in the Standard Model. In particular, tau anti-neutrinos have not been observed so far. We therefore propose an experiment to search for hidden particles and study tau neutrino physics at the same time.

Search for Hidden Particles (SHiP): a new experiment proposal

NASA Astrophysics Data System (ADS)

De Lellis, G.

2015-06-01

Searches for new physics with accelerators are being performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. We propose a new experimental facility meant to search for very weakly coupled particles in the few GeV mass domain. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored from the experimental point of view. A beam dump facility, built at CERN in the north area, using 400 GeV protons is a copious factory of charmed hadrons and could be used to probe the existence of such particles. The beam dump is also an ideal source of tau neutrinos, the less known particle in the Standard Model. In particular, tau anti-neutrinos have not been observed so far. We therefore propose an experiment to search for hidden particles and study tau neutrino physics at the same time.

Development and application of a particle-particle particle-mesh Ewald method for dispersion interactions.

PubMed

Isele-Holder, Rolf E; Mitchell, Wayne; Ismail, Ahmed E

2012-11-07

For inhomogeneous systems with interfaces, the inclusion of long-range dispersion interactions is necessary to achieve consistency between molecular simulation calculations and experimental results. For accurate and efficient incorporation of these contributions, we have implemented a particle-particle particle-mesh Ewald solver for dispersion (r(-6)) interactions into the LAMMPS molecular dynamics package. We demonstrate that the solver's O(N log N) scaling behavior allows its application to large-scale simulations. We carefully determine a set of parameters for the solver that provides accurate results and efficient computation. We perform a series of simulations with Lennard-Jones particles, SPC/E water, and hexane to show that with our choice of parameters the dependence of physical results on the chosen cutoff radius is removed. Physical results and computation time of these simulations are compared to results obtained using either a plain cutoff or a traditional Ewald sum for dispersion.

Discovering Complementary Colors from the Perspective of STEAM Education

ERIC Educational Resources Information Center

Karabey, Burak; Koyunkaya, Melike Yigit; Enginoglu, Turan; Yurumezoglu, Kemal

2018-01-01

This study explored the theory and applications of complementary colors using a technology-based activity designed from the perspective of STEAM education. Complementary colors and their areas of use were examined from the perspective of physics, mathematics and art, respectively. The study, which benefits from technology, makes the theory of…

Composition in the Quantum World

NASA Astrophysics Data System (ADS)

Hall, Edward Jonathan

This thesis presents a problem for the foundations of quantum mechanics. It arises from the way that theory describes the composition of larger systems in terms of smaller ones, and renders untenable a wide range of interpretations of quantum mechanics. That quantum mechanics is difficult to interpret is old news, given the well-known Measurement Problem. But the problem I raise is quite different, and in important respects more fundamental. In brief: The physical world exhibits mereological structure: physical objects have parts, which in turn have parts, and so on. A natural way to try to represent this structure is by means of a particle theory, according to which the physical world consists entirely enduring physical objects which themselves have no proper parts, but aggregates of which are, or compose, all physical objects. Elementary, non-relativistic quantum mechanics can be cast in this mold--at least, according to the usual expositions of that theory. But herein lies the problem: the standard attempt to give a systematic particle interpretation to elementary quantum mechanics results in nonsense, thanks to the well-established principle of Permutation Invariance, which constrains the quantum -mechanical description of systems containing identical particles. Specifically, it follows from the most minimal principles of a particle interpretation (much weaker than those needed to generate the Measurement Problem), together with Permutation Invariance, that systems identical in composition must have the same physical state. In other words, systems which merely have the same numbers of the same types of particles are therefore, at all times, perfect physical duplicates. This conclusion is absurd: e.g., it is quite plausible that some of those particles which compose my body make up a system identical in composition to some pepperoni pizza. Yet no part of me is a qualitative physical duplicate of any pepperoni pizza. Perhaps "you are what you eat" --but not in this sense! In what follows I develop the principles needed to explore this problem, contrast it with the Measurement Problem, and consider, finally, how it should influence our judgments of the relative merits of the many extant interpretations of quantum mechanics.

The Status of Physical Activity Opportunities in Idaho Schools

ERIC Educational Resources Information Center

Berei, Catherine P.; Karp, Grace Goc; Kauffman, Katie

2018-01-01

Recent literature indicates that low percentages of Idaho adolescents report being physically active on a daily basis. Research examines school PA, however, little focuses on Comprehensive School Physical Activity Programs (CSPAPs) from the perspectives of physical educators. This study explored Idaho physical educators' perceptions and…

Physical properties of elongated magnetic particles: magnetization and friction coefficient anisotropies.

PubMed

Vereda, Fernando; de Vicente, Juan; Hidalgo-Alvarez, Roque

2009-06-02

Anisotropy counts: A brief review of the main physical properties of elongated magnetic particles (EMPs) is presented. The most important characteristic of an EMP is the additional contribution of shape anisotropy to the total anisotropy energy of the particle, when compared to spherical magnetic particles. The electron micrograph shows Ni-ferrite microrods fabricated by the authors.We present an overview of the main physical properties of elongated magnetic particles (EMPs), including some of their more relevant properties in suspension. When compared to a spherical magnetic particle, the most important characteristic of an EMP is an additional contribution of shape anisotropy to the total anisotropy energy of the particle. Increasing aspect ratios also lead to an increase in both the critical single-domain size of a magnetic particle and its resistance to thermally activated spontaneous reversal of the magnetization. For single-domain EMPs, magnetization reversal occurs primarily by one of two modes, coherent rotation or curling, the latter being facilitated by larger aspect ratios. When EMPs are used to prepare colloidal suspensions, other physical properties come into play, such as their anisotropic friction coefficient and the consequent enhanced torque they experience in a shear flow, their tendency to align in the direction of an external field, to form less dense sediments and to entangle into more intricate aggregates. From a more practical point of view, EMPs are discussed in connection with two interesting types of magnetic colloids: magnetorheological fluids and suspensions for magnetic hyperthermia. Advances reported in the literature regarding the use of EMPs in these two systems are included. In the final section, we present a summary of the most relevant methods documented in the literature for the fabrication of EMPs, together with a list of the most common ferromagnetic materials that have been synthesized in the form of EMPs.

Einstein's physical strategy, energy conservation, symmetries, and stability: "But Grossmann & I believed that the conservation laws were not satisfied"

NASA Astrophysics Data System (ADS)

Pitts, J. Brian

2016-05-01

Recent work on the history of General Relativity by Renn et al. shows that Einstein found his field equations partly by a physical strategy including the Newtonian limit, the electromagnetic analogy, and energy conservation. Such themes are similar to those later used by particle physicists. How do Einstein's physical strategy and the particle physics derivations compare? What energy-momentum complex(es) did he use and why? Did Einstein tie conservation to symmetries, and if so, to which? How did his work relate to emerging knowledge (1911-1914) of the canonical energy-momentum tensor and its translation-induced conservation? After initially using energy-momentum tensors hand-crafted from the gravitational field equations, Einstein used an identity from his assumed linear coordinate covariance xμ‧ = Mνμ xν to relate it to the canonical tensor. Usually he avoided using matter Euler-Lagrange equations and so was not well positioned to use or reinvent the Herglotz-Mie-Born understanding that the canonical tensor was conserved due to translation symmetries, a result with roots in Lagrange, Hamilton and Jacobi. Whereas Mie and Born were concerned about the canonical tensor's asymmetry, Einstein did not need to worry because his Entwurf Lagrangian is modeled not so much on Maxwell's theory (which avoids negative-energies but gets an asymmetric canonical tensor as a result) as on a scalar theory (the Newtonian limit). Einstein's theory thus has a symmetric canonical energy-momentum tensor. But as a result, it also has 3 negative-energy field degrees of freedom (later called "ghosts" in particle physics). Thus the Entwurf theory fails a 1920s-1930s a priori particle physics stability test with antecedents in Lagrange's and Dirichlet's stability work; one might anticipate possible gravitational instability. This critique of the Entwurf theory can be compared with Einstein's 1915 critique of his Entwurf theory for not admitting rotating coordinates and not getting Mercury's perihelion right. One can live with absolute rotation but cannot live with instability. Particle physics also can be useful in the historiography of gravity and space-time, both in assessing the growth of objective knowledge and in suggesting novel lines of inquiry to see whether and how Einstein faced the substantially mathematical issues later encountered in particle physics. This topic can be a useful case study in the history of science on recently reconsidered questions of presentism, whiggism and the like. Future work will show how the history of General Relativity, especially Noether's work, sheds light on particle physics.

The search for new resonances in strong symmetry breaking scenarios with the ATLAS detector

NASA Astrophysics Data System (ADS)

Davies, Merlin

Using the most recent data collected by the ATLAS detector in pp collisions delivered by the LHC at 7 and 8 TeV, this thesis shall establish severe constraints on a variety of models going beyond the Standard Model (SM) of particle physics. More particularly, two types of hypothetical particles, existing in various theoretical models shall be studied and probed. The first type will be the search for vector-like quarks (VLQ) produced in pp collisions through electroweak couplings with the u and d quarks. The quest for these particles will be made as they decay into either W(ℓnu)+jet or Z(ℓℓ)+jet. There exist theoretical arguments that establish that, under certain reasonable conditions, single production of VLQ dominates over production in pairs. The particular topology of such events enables the implementation of effective techniques to extract signal over electroweak background. The second type is the search for resonant particles decaying to WZ when the gauge bosons W and Z decay leptonically. The final states detected by ATLAS therefore contain three leptons (e, or mu) and missing transverse energy. The distribution of the invariant mass of these objects will then be examined to determine the presence or absence of new resonances that manifest themselves as localized excesses in m(WZ). Despite the fact that, at first glance, these two new types of particles have very little in common, they are in fact both closely linked to electroweak symmetry breaking. In many theoretical models, the hypothetical existence of VLQ is put forward to counteract the top quark's contribution to radiative loop corrections of the Higgs mass, a calculation which assumes that the Higgs is an elementary particle. Concurrently, other models foretelling the existence WZ resonances alternatively suggest that the Higgs is a composite particle, completely rewriting the whole Higgs sector of the SM. In this perspective, the two analyses presented in this thesis have a fundamental link with the very nature of the Higgs, thereby extending our knowledge of the origin of particle masses. Ultimately, the two analyses did not observe any significant excess in their respective signal regions, paving the way for the computations of limits on the production cross section as a function of the mass of the resonances.

Materials for Nonlinear Optics Chemical Perspectives

DTIC Science & Technology

1991-01-01

formation of these polarized states has been referred to in terms of " viru transitions". The polarization behavior can be written in terms of the...MATERIALS FOR NONUNEAR OPTICS: CHEMICAL PERSPECTIVES also be corona -poled. Either way, the films are ideally suited for guided wave applications. With...electrodes, or a corona charging station, similar to that used in electrophotographic copiers, can be used to apply charged particles to the insulating

Universe or Multiverse?

NASA Astrophysics Data System (ADS)

Carr, Bernard

2009-08-01

Part I. Overviews: 1. Introduction and overview Bernard Carr; 2. Living in the multiverse Steven Weinberg; 3. Enlightenment, knowledge, ignorance, temptation Frank Wilczek; Part II. Cosmology and Astrophysics: 4. Cosmology and the multiverse Martin J. Rees; 5. The anthropic principle revisited Bernard Carr; 6. Cosmology from the top down Stephen Hawking; 7. The multiverse hierarchy Max Tegmark; 8. The inflationary universe Andrei Linde; 9. A model of anthropic reasoning: the dark to ordinary matter ratio Frank Wilczek; 10. Anthropic predictions: the case of the cosmological constant Alexander Vilenkin; 11. The definition and classification of universes James D. Bjorken; 12. M/string theory and anthropic reasoning Renata Kallosh; 13. The anthropic principle, dark energy and the LHC Savas Dimopoulos and Scott Thomas; Part III. Particle Physics and Quantum Theory: 14. Quarks, electrons and atoms in closely related universes Craig J. Hogan; 15. The fine-tuning problems of particle physics and anthropic mechanisms John F. Donoghue; 16. The anthropic landscape of string theory Leonard Susskind; 17. Cosmology and the many worlds interpretation of quantum mechanics Viatcheslav Mukhanov; 18. Anthropic reasoning and quantum cosmology James B. Hartle; 19. Micro-anthropic principle for quantum theory Brandon Carter; Part IV. More General Philosophical Issues: 20. Scientific alternatives to the anthropic principle Lee Smolin; 21. Making predictions in a multiverse: conundrums, dangers, coincidences Anthony Aguirre; 22. Multiverses: description, uniqueness and testing George Ellis; 23. Predictions and tests of multiverse theories Don N. Page; 24. Observation selection theory and cosmological fine-tuning Nick Bostrom; 25. Are anthropic arguments, involving multiverses and beyond, legitimate? William R. Stoeger; 26. The multiverse hypothesis: a theistic perspective Robin Collins; 27. Living in a simulated universe John D. Barrow; 28. Universes galore: where will it all end? Paul Davies; Index.

Current experiments in elementary particle physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wohl, C.G.; Armstrong, F.E., Oyanagi, Y.; Dodder, D.C.

1987-03-01

This report contains summaries of 720 recent and current experiments in elementary particle physics (experiments that finished taking data before 1980 are excluded). Included are experiments at Brookhaven, CERN, CESR, DESY, Fermilab, Moscow Institute of Theoretical and Experimental Physics, Tokyo Institute of Nuclear Studies, KEK, LAMPF, Leningrad Nuclear Physics Institute, Saclay, Serpukhov, SIN, SLAC, and TRIUMF, and also experiments on proton decay. Instructions are given for searching online the computer database (maintained under the SLAC/SPIRES system) that contains the summaries. Properties of the fixed-target beams at most of the laboratories are summarized.

Big Bang Day : Physics Rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-10-07

Is particle physics the new rock 'n' roll? The fundamental questions about the nature of the universe that particle physics hopes to answer have attracted the attention of some very high profile and unusual fans. Alan Alda, Ben Miller, Eddie Izzard, Dara O'Briain and John Barrowman all have interests in this branch of physics. Brian Cox - CERN physicist, and former member of 90's band D:Ream, tracks down some very well known celebrity enthusiasts and takes a light-hearted look at why this subject can appeal to all of us.

Big Bang Day : Physics Rocks

ScienceCinema

None

2017-12-09

Is particle physics the new rock 'n' roll? The fundamental questions about the nature of the universe that particle physics hopes to answer have attracted the attention of some very high profile and unusual fans. Alan Alda, Ben Miller, Eddie Izzard, Dara O'Briain and John Barrowman all have interests in this branch of physics. Brian Cox - CERN physicist, and former member of 90's band D:Ream, tracks down some very well known celebrity enthusiasts and takes a light-hearted look at why this subject can appeal to all of us.

Effect of milling on the plastic and the elastic stiffness of lactose particles.

PubMed

Pazesh, Samaneh; Persson, Ann-Sofie; Berggren, Jonas; Alderborn, Göran

2018-03-01

The purpose of this study was to investigate the effect of degree of disorder of a series of α-lactose monohydrate powders, prepared by milling for different time periods, on the plastic and the elastic stiffness of the particles. As references, a series of physical mixtures consisting of original crystalline particles and amorphous particles obtained by spray-drying was used. In addition, the effect of powder pre-storage humidity on the mechanical properties was investigated. For milled particles of a low degree of disorder, a decreased particle size increased the particle plastic stiffness. For milled particles of constant particle size, the plastic stiffness decreased with an increased degree of disorder while the elastic stiffness seemed nearly independent of the degree of disorder. The presence of moisture caused a recrystallisation of milled particles with low degree of disorder which increased their plastic stiffness. For the physical mixtures of crystalline and amorphous particles, similar relationships between plastic stiffness and amorphous content as for the milled powders were obtained. A reasonable explanation is that the nature of the milled particles is represented by a two-state system with crystalline and amorphous domains. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorelenkov, Nikolai N

The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEsmore » (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).« less

A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

NASA Astrophysics Data System (ADS)

Verkhoglyadova, Olga P.; Zank, Gary P.; Li, Gang

2015-02-01

Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the "pump mechanism"), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the particle composition of SEP events, we address in some detail the injection problem. Although steady-state models can improve our understanding of the diffusive shock acceleration mechanism, SEP events are inherently time-dependent. We therefore review the time-dependent theory of DSA in some detail, including estimating possible maximum particle energies and particle escape from the shock complex. We also discuss generalizations of the diffusive transport approach to modeling particle acceleration by considering a more general description based on the focused transport equation. The escape of accelerated particles from the shock requires that their subsequent transport in the interplanetary medium be modeled and the consequence of interplanetary transport can lead to the complex spectra and compositional profiles that are observed frequently. The different approaches to particle transport in the inner heliosphere are reviewed. The various numerical models that have been developed to solve the gradual SEP problem are reviewed. Explicit comparisons of modeling results with observations of large SEP events are discussed. A summary of current progress and the outlook on the SEP problem and remaining open questions conclude the review.

Heterogenous Combustion of Porous Graphite Particles in Normal and Microgravity

NASA Technical Reports Server (NTRS)

Chelliah, Harsha K.; Miller, Fletcher J.; Delisle, Andrew J.

2001-01-01

Combustion of solid fuel particles has many important applications, including power generation and space propulsion systems. The current models available for describing the combustion process of these particles, especially porous solid particles, include various simplifying approximations. One of the most limiting approximations is the lumping of the physical properties of the porous fuel with the heterogeneous chemical reaction rate constants. The primary objective of the present work is to develop a rigorous model that could decouple such physical and chemical effects from the global heterogeneous reaction rates. For the purpose of validating this model, experiments with porous graphite particles of varying sizes and porosity are being performed. The details of this experimental and theoretical model development effort are described.

Particle Physics on the Eve of Lhc

NASA Astrophysics Data System (ADS)

Studenikin, Alexander I.

2009-01-01

Fundamentals of particle physics. The quantum number of color, colored quarks and dynamic models of Hadrons composed of quasifree quarks / V. Matveev, A. Tavkhelidze. Discovery of the color degree of freedom in particle physics: a personal perspective / O. W. Greenberg. The evolution of the concepts of energy, momentum, and mass from Newton and Lomonosov to Einstein and Feynman / L. Okun -- Physics at accelerators and studies in SM and beyond. Search for new physics at LHC (CMS) / N. Krasnikov. Measuring the Higgs Boson(s) at ATLAS / C. Kourkoumelis. Beyond the standard model physics reach of the ATLAS experiment / G. Unel. The status of the International Linear Collider / B. Foster. Review of results of the electron-proton collider HERA / V. Chekelian. Recent results from the Tevatron on CKM matrix elements from Bs oscillations and single top production, and studies of CP violation in Bs Decays / J. P. Fernández. Direct observation of the strange b Barion [symbol] / L. Vertogradov. Search for new physics in rare B Decays at LHCb / V. Egorychev. CKM angle measurements at LHCb / S. Barsuk. Collider searches for extra spatial dimensions and black holes / G. Landsberg -- Neutrino Physics. Results of the MiniBooNE neutrino oscillation experiment / Z. Djurcic. MINOS results and prospects / J. P. Ochoa-Ricoux. The new result of the neutrino magnetic moment measurement in the GEMMA experiment / A. G. Beda ... [et al.]. The Baikal neutrino experiment: status, selected physics results, and perspectives / V. Aynutdinov ... [et al.]. Neutrino telescopes in the deep sea / V. Flaminio. Double beta decay: present status / A. S. Barabash. Beta-beams / C. Volpe. T2K experiment / K. Sakashita. Non-standard neutrino physics probed by Tokai-to-Kamioka-Korea two-detector complex / N. Cipriano Ribeiro ... [et al.]. Sterile neutrinos: from cosmology to the LHC / F. Vannucci. From Cuoricino to Cuore towards the inverted hierarchy region / C. Nones. The MARE experiment: calorimetric approach to the direct measurement of the neutrino mass / E. Andreotti. Electron angular correlation in neutrinoless double beta decay and new physics / A. Ali, A. Borisov, D. Zhuridov. Neutrino energy quantization in rotating medium / A. Grigoriev, A. Studenikin. Neutrino propagation in dense magnetized matter / E. V. Arbuzova, A. E. Lobanov, E. M. Murchikova. Plasma induced neutrino spin flip via the neutrino magnetic moment / A. Kuznetsov, N. Mikheev -- Astroparticle physics and cosmology. International Russian-Italian mission "RIM-PAMELA" / A. M. Galper .. [et al.]. Dark Matter searches with AMS-02 experiment / A. Malinin. Investigating the dark halo / R. Bernabei ... [et al.]. Search for rare processes at Gran Sasso / P. Belli ... [et al.]. Anisotropy of Dark Matter annihilation and remnants of Dark Matter clumps in the galaxy / V. Berezinsky, V. Dokuchaev, Yu. Eroshenko. Current observational constraints on inflationary models / E. Mikheeva. Phase transitions in dense quark matter in a constant curvature gravitational field / D. Ebert, V. Ch. Zhukovsky, A. V. Tyukov. Construction of exact solutions in two-fields models / S. Yu. Vernov. Quantum systems bound by gravity / M. L. Fil'chenkov, S. V. Kopylov, Y. P. Laptev -- CP violation and rare decays. Some puzzles of rare B-Decays / A. B. Kaidalov. Measurements of CP violation in b decays and CKM parameters / J. Chauveau. Evidence for D[symbol] mixing at BaBar / M. V. Purohit. Search for direct CP violation in charged kaon decays from NA48/2 experiment / S. Balev. [symbol] scattering lengths from measurements of K[symbol] and K± -> [symbol] decays at NA48/2 / D. Madigozhin. Rare kaon and hyperon decays in NA48 experiment / N. Molokanova. THE K+ -> [symbol]+vv¯ experiment at CERN / Yu. Potrebenikov. Recent KLOE results / B. Di Micco.Decay constants and masses of heavy-light mesons in field correlator method / A. M. Badalian. Bilinear R-parity violation in rare meson decays / A. Ali, A. V. Borisov, M. V. Sidorova. Final state interaction in K -> 2[symbol] decay / E. Shabalin -- Hadron physics. Collective effects in central heavy-ion collisions / G. I. Lykasov ... [et al.]. Stringy phenomena in Yang-Mills plasma / V. I. Zakharov. Lattice results on gluon and ghost propagators in Landau gauge / I. L. Bogolubsky ... [et al.]. [symbol] and [symbol] excited states in field correlator method / I. Narodetskii, A. Veselov. Theory of quark-gluon plasma and phase transition / E. V. Komarov, Yu. A. Simonov. Chiral symmetry breaking and the Lorentz nature of confinement / A. V. Nefediev. Structure function moments of proton and neutron / M. Osipenko. Higgs decay to bb: different approaches to resummation of QCD effects / A. L. Kataev, V. T. Kim. A novel integral representation for the Adler function and its behavior at low energies / A. V. Nesterenko. QCD test of z-scaling for [symbol]-meson production in pp collisions at high energies / M. Tokarev, T. Dedovich. Quark mixing in the standard model and the space rotations / G. Dattoli, K. Zhukovsky. Analytic approach to constructing effective theory of strong interactions and its application to pion-nucleon scattering / A. N. Safronov -- New developments in quantum field theory. On the origin of families and their mass matrices with the approach unifying spin and charges, prediction for new families / N. S. Mankoc Borstnik. Z[symbol] electric strings and center vortices in SU(2) lattice gauge theory / M. I. Polikarpov, P. V. Buividovich. Upper bound on the lightest neutralino mass in the minimal non-minimal supersymmetric standard model / S. Hesselbach ... [et al.]. Application of higher derivative regularization to calculation of quantum corrections in N=l supersymmetric theories / K. Stepanyantz. Nonperturbative quantum relativistic effects in the confinement mechanism for particles in a deep potential well / K. A. Sveshnikov, M. V. Ulybyshev. Khalfin's theorem and neutral mesons subsystem / K. Urbanowski. Effective lagrangians and field theory on a lattice / O. V. Pavlovsky. String-like electrostatic interaction from QED with infinite magnetic field / A. E. Shabad, V. V. Usov. QFT systems with 2D spatial defects / I. V. Fialkovsky, V. N. Markov, Yu. M. Pismak. Bound state problems and radiative effects in extended electrodynamics with Lorentz violation / I. E. Frolov, O. G. Kharlanov, V. Ch. Zhukovsky. Particles with low binding energy in a strong stationary magnetic field / E. V. Arbuzova, G. A. Kravtsova, V. N. Rodionov. Triangle anomaly and radiatively induced Lorentz and CPT violation in electrodynamics / A. E. Lobanov, A. P. Venediktov. The comparative analysis of the angular distribution of synchrotron radiation for a spinless particle in classic and quantum theories / V. G. Bagrov, A. N. Burimova, A. A. Gusev. Problem of the spin light identification / V. A. Bordovitsyn, V. V. Telushkin. Simulation the nuclear interaction / T. F. Kamalov. Unstable leptons and (u - e - [symbol])-universality / O. Kosmachev. Generalized Dirac equation describing the quark structure of nucleons / A. Rabinowitch. Unique geometrization of material and electromagnetic wave fields / O. Olkhov -- Problems of intelligentsia. The conscience of the intelligentsia / J. K. Bleimaier.

Modeling photoacoustic spectral features of micron-sized particles

NASA Astrophysics Data System (ADS)

Strohm, Eric M.; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael C.

2014-10-01

The photoacoustic signal generated from particles when irradiated by light is determined by attributes of the particle such as the size, speed of sound, morphology and the optical absorption coefficient. Unique features such as periodically varying minima and maxima are observed throughout the photoacoustic signal power spectrum, where the periodicity depends on these physical attributes. The frequency content of the photoacoustic signals can be used to obtain the physical attributes of unknown particles by comparison to analytical solutions of homogeneous symmetric geometric structures, such as spheres. However, analytical solutions do not exist for irregularly shaped particles, inhomogeneous particles or particles near structures. A finite element model (FEM) was used to simulate photoacoustic wave propagation from four different particle configurations: a homogeneous particle suspended in water, a homogeneous particle on a reflecting boundary, an inhomogeneous particle with an absorbing shell and non-absorbing core, and an irregularly shaped particle such as a red blood cell. Biocompatible perfluorocarbon droplets, 3-5 μm in diameter containing optically absorbing nanoparticles were used as the representative ideal particles, as they are spherical, homogeneous, optically translucent, and have known physical properties. The photoacoustic spectrum of micron-sized single droplets in suspension and on a reflecting boundary were measured over the frequency range of 100-500 MHz and compared directly to analytical models and the FEM. Good agreement between the analytical model, FEM and measured values were observed for a droplet in suspension, where the spectral minima agreed to within a 3.3 MHz standard deviation. For a droplet on a reflecting boundary, spectral features were correctly reproduced using the FEM but not the analytical model. The photoacoustic spectra from other common particle configurations such as particle with an absorbing shell and a biconcave-shaped red blood cell were also investigated, where unique features in the power spectrum could be used to identify them.

PARTICLE GROWTH IN HIGH-SPEED PARTICLE BEAM INLETS. (R823980)

EPA Science Inventory

Physical and chemical characterization of airborne particles is essential for determining their role in air pollution. Characterization instruments typically employ the use of sonic nozzles that transmit a wide range of particle sizes to a low-pressure region. The carrier gas ...

A high-speed tracking algorithm for dense granular media

NASA Astrophysics Data System (ADS)

Cerda, Mauricio; Navarro, Cristóbal A.; Silva, Juan; Waitukaitis, Scott R.; Mujica, Nicolás; Hitschfeld, Nancy

2018-06-01

Many fields of study, including medical imaging, granular physics, colloidal physics, and active matter, require the precise identification and tracking of particle-like objects in images. While many algorithms exist to track particles in diffuse conditions, these often perform poorly when particles are densely packed together-as in, for example, solid-like systems of granular materials. Incorrect particle identification can have significant effects on the calculation of physical quantities, which makes the development of more precise and faster tracking algorithms a worthwhile endeavor. In this work, we present a new tracking algorithm to identify particles in dense systems that is both highly accurate and fast. We demonstrate the efficacy of our approach by analyzing images of dense, solid-state granular media, where we achieve an identification error of 5% in the worst evaluated cases. Going further, we propose a parallelization strategy for our algorithm using a GPU, which results in a speedup of up to 10 × when compared to a sequential CPU implementation in C and up to 40 × when compared to the reference MATLAB library widely used for particle tracking. Our results extend the capabilities of state-of-the-art particle tracking methods by allowing fast, high-fidelity detection in dense media at high resolutions.

Simulation of orientational coherent effects via Geant4

NASA Astrophysics Data System (ADS)

Bagli, E.; Asai, M.; Brandt, D.; Dotti, A.; Guidi, V.; Verderi, M.; Wright, D.

2017-10-01

Simulation of orientational coherent effects via Geant4 beam manipulation of high-and very-high-energy particle beams is a hot topic in accelerator physics. Coherent effects of ultra-relativistic particles in bent crystals allow the steering of particle trajectories thanks to the strong electrical field generated between atomic planes. Recently, a collimation experiment with bent crystals was carried out at the CERN-LHC, paving the way to the usage of such technology in current and future accelerators. Geant4 is a widely used object-oriented tool-kit for the Monte Carlo simulation of the interaction of particles with matter in high-energy physics. Moreover, its areas of application include also nuclear and accelerator physics, as well as studies in medical and space science. We present the first Geant4 extension for the simulation of orientational effects in straight and bent crystals for high energy charged particles. The model allows the manipulation of particle trajectories by means of straight and bent crystals and the scaling of the cross sections of hadronic and electromagnetic processes for channeled particles. Based on such a model, an extension of the Geant4 toolkit has been developed. The code and the model have been validated by comparison with published experimental data regarding the deflection efficiency via channeling and the variation of the rate of inelastic nuclear interactions.

Correlation of Particle Traversals with Clonogenic Survival Using Cell-Fluorescent Ion Track Hybrid Detector.

PubMed

Dokic, Ivana; Niklas, Martin; Zimmermann, Ferdinand; Mairani, Andrea; Seidel, Philipp; Krunic, Damir; Jäkel, Oliver; Debus, Jürgen; Greilich, Steffen; Abdollahi, Amir

2015-01-01

Development of novel approaches linking the physical characteristics of particles with biological responses are of high relevance for the field of particle therapy. In radiobiology, the clonogenic survival of cells is considered the gold standard assay for the assessment of cellular sensitivity to ionizing radiation. Toward further development of next generation biodosimeters in particle therapy, cell-fluorescent ion track hybrid detector (Cell-FIT-HD) was recently engineered by our group and successfully employed to study physical particle track information in correlation with irradiation-induced DNA damage in cell nuclei. In this work, we investigated the feasibility of Cell-FIT-HD as a tool to study the effects of clinical beams on cellular clonogenic survival. Tumor cells were grown on the fluorescent nuclear track detector as cell culture, mimicking the standard procedures for clonogenic assay. Cell-FIT-HD was used to detect the spatial distribution of particle tracks within colony-initiating cells. The physical data were associated with radiation-induced foci as surrogates for DNA double-strand breaks, the hallmark of radiation-induced cell lethality. Long-term cell fate was monitored to determine the ability of cells to form colonies. We report the first successful detection of particle traversal within colony-initiating cells at subcellular resolution using Cell-FIT-HD.

Enhancement and degradation of the R2* relaxation rate resulting from the encapsulation of magnetic particles with hydrophilic coatings.

PubMed

de Haan, Hendrick W; Paquet, Chantal

2011-12-01

The effects of including a hydrophilic coating around the particles are studied across a wide range of particle sizes by performing Monte Carlo simulations of protons diffusing through a system of magnetic particles. A physically realistic methodology of implementing the coating by cross boundary jump scaling and transition probabilities at the coating surface is developed. Using this formulation, the coating has three distinct impacts on the relaxation rate: an enhancement at small particle sizes, a degradation at intermediate particle sizes, and no effect at large particles sizes. These varied effects are reconciled with the underlying dephasing mechanisms by using the concept of a full dephasing zone to present a physical picture of the dephasing process with and without the coating for all sizes. The enhancement at small particle sizes is studied systemically to demonstrate the existence of an optimal ratio of diffusion coefficients inside/outside the coating to achieve maximal increase in the relaxation rate. Copyright © 2011 Wiley Periodicals, Inc.

Particles, Quarks, Leptons and Coloured Glue.

ERIC Educational Resources Information Center

Ryder, Lewis

1980-01-01

Explains the current situation in particle physics by reviewing the three major periods in the development of atomic theory. Outlines the current picture of fundamental particles and identifies five major problems with this model. (GS)

A guide to experimental particle physics literature, 1991-1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezhela, V.V.; Filimonov, B.B.; Lugovsky, S.B.

1996-10-01

We present an indexed guide to experimental particle physics literature for the years 1991 - 1996. Approximately 4200 papers are indexed by (1) Beam/Target/Momentum (2) Reaction/Momentum/Data-Descriptor (including the final state) (3) Particle/Decay (4) Accelerator/Experiment/Detector. All indices are cross-referenced to the paper`s title and references in the ID/Reference/Title index. The information presented in this guide is also publicly available on a regularly-updated DATAGUIDE database from the World Wide Web.

A Reply to ''Reinterpretation of Students' Ideas When Reasoning about Particle Model Illustrations. A Response to ''Using Animations in Identifying General Chemistry Students' Misconceptions and Evaluating Their Knowledge Transfer Relating to Particle Position in Physical Changes'' by Smith and Villarreal (2015)''

ERIC Educational Resources Information Center

Smith, K. Christopher; Villarreal, Savannah

2015-01-01

In this reply to Elon Langbeheim's response to an article recently published in this journal, authors Smith and Villarreal identify several types of general chemistry students' misconceptions concerning the concept of particle position during physical change. They focus their response on one of the misconceptions identified as such: Given a solid…

Innovative experimental particle physics through technological advances: Past, present and future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, Harry W.K.; /Fermilab

This mini-course gives an introduction to the techniques used in experimental particle physics with an emphasis on the impact of technological advances. The basic detector types and particle accelerator facilities will be briefly covered with examples of their use and with comparisons. The mini-course ends with what can be expected in the near future from current technology advances. The mini-course is intended for graduate students and post-docs and as an introduction to experimental techniques for theorists.

PARTICLE PHYSICS: CERN Gives Higgs Hunters Extra Month to Collect Data.

PubMed

Morton, O

2000-09-22

After 11 years of banging electrons and positrons together at higher energies than any other machine in the world, CERN, the European laboratory for particle physics, had decided to shut down the Large Electron-Positron collider (LEP) and install a new machine, the Large Hadron Collider (LHC), in its 27-kilometer tunnel. In 2005, the LHC will start bashing protons together at even higher energies. But tantalizing hints of a long-sought fundamental particle have forced CERN managers to grant LEP a month's reprieve.

[The influence of spray drying process conditions on physical, chemical properties and lung inhaling performance of Panax notoginseng saponins - tanshinone II A composite particles].

PubMed

Wang, Hua-Mei; Fu, Ting-Ming; Guo, Li-Wei

2013-06-01

This study is to report the influence of conditions in spray drying process on physical and chemical properties and lung inhaling performance of Panax notoginseng Saponins - Tanshinone II A composite particles. According to the physical and chemical properties of the two types of components within the composite particles, three solvent systems were selected including ethanol, ethanol : acetone (9 : 1, v/v) and ethanol : acetone (4 : 1, v/v), and three inlet temperature: 110 degrees C, 120 degrees C, 130 degrees C to prepare seven different composite particle samples; each sample was characterized using laser diffraction, scanning electron microscopy (SEM), dynamic vapour sorption (DVS) and atomic force microscope (AFM), and their aerodynamic behavior was evaluated by a Next Generation Impactor (NGI). The results indicate that under the conditions of using the mixed solvent system of ethanol--acetone volume ratio of 9 : 1, and the inlet temperature of 110 degrees C, the resulting composite particles showed rough surface, with more tanshinone II A distributing in the outer layer, such composite particles have the best lung inhaling performance and the fine particle fraction (FPF) close to 60%. Finally it is concluded that by adjusting the conditions in co-spray drying process, the distribution amount and existence form of tanshinone II A in the outer layer of the particles can be changed so that to enhance lung inhaling performance of the drug composite particles.

CMS Physics Technical Design Report, Volume II: Physics Performance

NASA Astrophysics Data System (ADS)

CMS Collaboration

2007-06-01

CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider (LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and luminosity when it begins operation in 2007. The principal aim of this report is to present the strategy of CMS to explore the rich physics programme offered by the LHC. This volume demonstrates the physics capability of the CMS experiment. The prime goals of CMS are to explore physics at the TeV scale and to study the mechanism of electroweak symmetry breaking—through the discovery of the Higgs particle or otherwise. To carry out this task, CMS must be prepared to search for new particles, such as the Higgs boson or supersymmetric partners of the Standard Model particles, from the start-up of the LHC since new physics at the TeV scale may manifest itself with modest data samples of the order of a few fb -1 or less. The analysis tools that have been developed are applied to study in great detail and with all the methodology of performing an analysis on CMS data specific benchmark processes upon which to gauge the performance of CMS. These processes cover several Higgs boson decay channels, the production and decay of new particles such as Z' and supersymmetric particles, B s production and processes in heavy ion collisions. The simulation of these benchmark processes includes subtle effects such as possible detector miscalibration and misalignment. Besides these benchmark processes, the physics reach of CMS is studied for a large number of signatures arising in the Standard Model and also in theories beyond the Standard Model for integrated luminosities ranging from 1 fb -1 to 30 fb -1 . The Standard Model processes include QCD, B -physics, diffraction, detailed studies of the top quark properties, and electroweak physics topics such as the W and Z 0 boson properties. The production and decay of the Higgs particle is studied for many observable decays, and the precision with which the Higgs boson properties can be derived is determined. About ten different supersymmetry benchmark points are analysed using full simulation. The CMS discovery reach is evaluated in the SUSY parameter space covering a large variety of decay signatures. Furthermore, the discovery reach for a plethora of alternative models for new physics is explored, notably extra dimensions, new vector boson high mass states, little Higgs models, technicolour and others. Methods to discriminate between models have been investigated. This report is organized as follows. Chapter 1, the Introduction, describes the context of this document. Chapters 2 6 describe examples of full analyses, with photons, electrons, muons, jets, missing E T , B-mesons and τ's, and for quarkonia in heavy ion collisions. Chapters 7 15 describe the physics reach for Standard Model processes, Higgs discovery and searches for new physics beyond the Standard Model.

A Perspective on Physical Organic Chemistry

PubMed Central

2015-01-01

A perspective on the development of mechanistic carbene chemistry is presented. The author will point out questions that have been answered, and a next generation of questions will be proposed. PMID:24571434

Emerging Technologies in Physics Education

ERIC Educational Resources Information Center

Krusberg, Zosia A. C.

2007-01-01

Three emerging technologies in physics education are evaluated from the interdisciplinary perspective of cognitive science and physics education research. The technologies--Physlet Physics, the Andes Intelligent Tutoring System (ITS), and Microcomputer-Based Laboratory (MBL) Tools--are assessed particularly in terms of their potential at promoting…

The Gibbs paradox and the physical criteria for indistinguishability of identical particles

NASA Astrophysics Data System (ADS)

Unnikrishnan, C. S.

2016-08-01

Gibbs paradox in the context of statistical mechanics addresses the issue of additivity of entropy of mixing gases. The usual discussion attributes the paradoxical situation to classical distinguishability of identical particles and credits quantum theory for enabling indistinguishability of identical particles to solve the problem. We argue that indistinguishability of identical particles is already a feature in classical mechanics and this is clearly brought out when the problem is treated in the language of information and associated entropy. We pinpoint the physical criteria for indistinguishability that is crucial for the treatment of the Gibbs’ problem and the consistency of its solution with conventional thermodynamics. Quantum mechanics provides a quantitative criterion, not possible in the classical picture, for the degree of indistinguishability in terms of visibility of quantum interference, or overlap of the states as pointed out by von Neumann, thereby endowing the entropy expression with mathematical continuity and physical reasonableness.

Beyond the standard model of particle physics.

PubMed

Virdee, T S

2016-08-28

The Large Hadron Collider (LHC) at CERN and its experiments were conceived to tackle open questions in particle physics. The mechanism of the generation of mass of fundamental particles has been elucidated with the discovery of the Higgs boson. It is clear that the standard model is not the final theory. The open questions still awaiting clues or answers, from the LHC and other experiments, include: What is the composition of dark matter and of dark energy? Why is there more matter than anti-matter? Are there more space dimensions than the familiar three? What is the path to the unification of all the fundamental forces? This talk will discuss the status of, and prospects for, the search for new particles, symmetries and forces in order to address the open questions.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. © 2016 The Author(s).