Hard probes of short-range nucleon-nucleon correlations

Energy Technology Data Exchange (ETDEWEB)

J. Arrington, D. W. Higinbotham, G. Rosner, M. Sargsian

2012-10-01

The strong interaction of nucleons at short distances leads to a high-momentum component to the nuclear wave function, associated with short-range correlations between nucleons. These short-range, high-momentum structures in nuclei are one of the least well understood aspects of nuclear matter, relating to strength outside of the typical mean-field approaches to calculating the structure of nuclei. While it is difficult to study these short-range components, significant progress has been made over the last decade in determining how to cleanly isolate short-range correlations in nuclei. We have moved from asking if such structures exist, to mapping out their strength in nuclei and studying their microscopic structure. A combination of several different measurements, made possible by high-luminosity and high-energy accelerators, coupled with an improved understanding of the reaction mechanism issues involved in studying these structures, has led to significant progress, and provided significant new information on the nature of these small, highly-excited structures in nuclei. We review the general issues related to short-range correlations, survey recent experiments aimed at probing these short-range structures, and lay out future possibilities to further these studies.

German writers and the Intermediate-range Nuclear Forces debate in the 1980s

International Nuclear Information System (INIS)

Stokes, A.M.

1991-01-01

In 1979, NATO announced its decision to deploy American intermediate-range nuclear missiles throughout Western Europe. From then until 1987, when the historic Intermediate-range Nuclear forces (INF) treaty provided for the withdrawal of these weapons as well as those deployed by the Soviets in Eastern Europe, the issue of nuclear weapons preoccupied many Europeans, particularly Germans. Beginning in 1980, fear of nuclear war, with the two Germanies as a potential battlefield, mobilized the largest peace movement that the Federal Republic had witnessed since the fifties, occasioned a massive increase in peace propaganda in East Germany, and brought to public notice that country's first unofficial peace movement. Throughout most of the eighties, writers in both German states opposed missile deployment. This study examines their aims and achievements in this effort and investigates the implications of political engagement for the aesthetic production of selected authors. Analysis of press reports, writers' speeches, interviews, essays and literary texts yielded the following results: INF deployment motivated writers of all political persuasions to take up a variety of peace-oriented pursuits

Molecular dynamics simulations of short-range force systems on 1024-node hypercubes

International Nuclear Information System (INIS)

Plimpton, S.J.

1990-01-01

In this paper, two parallel algorithms for classical molecular dynamics are presented. The first assigns each processor to a subset of particles; the second assigns each to a fixed region of 3d space. The algorithms are implemented on 1024-node hypercubes for problems characterized by short-range forces, diffusion (so that each particle's neighbors change in time), and problem size ranging from 250 to 10000 particles. Timings for the algorithms on the 1024-node NCUBE/ten and the newer NCUBE 2 hypercubes are given. The latter is found to be competitive with a CRAY-XMP, running an optimized serial algorithm. For smaller problems the NCUBE 2 and CRAY-XMP are roughly the same; for larger ones the NCUBE 2 is up to twice as fast. Parallel efficiencies of the algorithms and communication parameters for the two hypercubes are also examined

Dressed dibaryon production as a new mechanism for basic nuclear force and meson-exchange currents

International Nuclear Information System (INIS)

Kukulin, V.I.

2003-01-01

A novel concept for the nuclear force is introduced. The approach assumes that a specific dressed six-quark state (dressed dibaryon) is generated in NN collision at intermediate and short ranges. The new dressing mechanism providing π-, σ-, ρ- and ω-meson clouds around the six quark core is discussed. These novel components produce both strong intermediate-range attraction and short-range repulsion in the NN sector due to the s-channel exchange mechanism which is supplemented with conventional π- and 2π- Yukawa exchanges at intermediate and long ranges. The model developed is demonstrated to lead to numerous new effects and contributions in many fields of nuclear physics. (author)

Probing the short range behavior of nuclei with high PT photo- and electro-nuclear reactions

International Nuclear Information System (INIS)

Laget, J.M.

1990-01-01

The short range behavior of the nucleus and the use of the nucleus as a filter are studied. Special emphasis is given to photon and hadron induced reactions. The components of the nuclear wave function are described. The evidences of hard scattering processes in reactions induced by real photons as well as by hadrons on free nucleus are reviewed. The spin observables are also investigated. The perspectives opened by these studies in the nuclear environment are considered

Analysis of long- and short-range contribution to adhesion work in cardiac fibroblasts: An atomic force microscopy study

Energy Technology Data Exchange (ETDEWEB)

Sbaizero, O., E-mail: sbaizero@units.it [Department of Engineering and Architecture, University of Trieste (Italy); University of Colorado Cardiovascular Institute, University of Colorado Denver, Aurora (United States); DelFavero, G. [Department of Engineering and Architecture, University of Trieste (Italy); Martinelli, V. [International Center for Genetic Engineering and Biotechnology, Trieste (Italy); Long, C.S.; Mestroni, L. [University of Colorado Cardiovascular Institute, University of Colorado Denver, Aurora (United States)

2015-04-01

Atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS) and Poisson statistic were used to analyze the detachment work recorded during the removal of gold-covered microspheres from cardiac fibroblasts. The effect of Cytochalasin D, a disruptor of the actin cytoskeleton, on cell adhesion was also tested. The adhesion work was assessed using a Poisson analysis also derived from single-cell force spectroscopy retracting curves. The use of Poisson analysis to get adhesion work from AFM curves is quite a novel method, and in this case, proved to be effective to study the short-range and long-range contributions to the adhesion work. This method avoids the difficult identification of minor peaks in the AFM retracting curves by creating what can be considered an average adhesion work. Even though the effect of actin depolymerisation is well documented, its use revealed that control cardiac fibroblasts (CT) exhibit a work of adhesion at least 5 times higher than that of the Cytochalasin treated cells. However, our results indicate that in both cells short-range and long-range contributions to the adhesion work are nearly equal and the same heterogeneity index describes both cells. Therefore, we infer that the different adhesion behaviors might be explained by the presence of fewer membrane adhesion molecules available at the AFM tip–cell interface under circumstances where the actin cytoskeleton has been disrupted. - Highlights: • AFM force–deformation curve was used to characterize the cardiac fibroblast adhesion behavior. • The amount and nature of adhesion were assessed using a Poisson analysis applied to the AFM curve. • The work of adhesion for control cells was about four times higher than that of the Cyt-D treated cells. • Short- and long-range contributions to adhesion are nearly equal for both control and treated cells.

The role of the form factor and short-range correlation in the relativistic Hartree-Fock model for nuclear matter

Science.gov (United States)

Hu, J.; Toki, H.; Wen, W.; Shen, H.

2010-03-01

The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size ( Λ ˜ 1.0 -2.0GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ -meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ -meson energies in the relativistic Hartree-Fock approximation for nuclear matter.

The role of the form factor and short-range correlation in the relativistic Hartree-Fock model for nuclear matter

International Nuclear Information System (INIS)

Hu, J.; Toki, H.; Wen, W.; Shen, H.

2010-01-01

The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size (Λ∝1.0 -2.0 GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ-meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ-meson energies in the relativistic Hartree-Fock approximation for nuclear matter. (orig.)

Modernization of US Nuclear Forces: Costs in Perspective

International Nuclear Information System (INIS)

Tapia-Jimenez, D.

2017-01-01

This short research paper addresses two topics that have emerged in the debate about whether, when, and how to modernize U.S. nuclear forces.1 The first topic relates to the size and scale of the planned nuclear force, with some critics of the modernization plan arguing that the United States is simply replicating the Cold War force for a very different era. The second topic relates to the cost of the modernization effort, with some critics arguing that the cost is unaffordable.2 This paper begins with a review of the changes in the size and scale of U.S. nuclear forces since the Cold War. It then examines the expected costs of modernization in a comparative perspective.

Modernization of US Nuclear Forces: Costs in Perspective

Energy Technology Data Exchange (ETDEWEB)

Tapia-Jimenez, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-04-12

This short research paper addresses two topics that have emerged in the debate about whether, when, and how to modernize U.S. nuclear forces.1 The first topic relates to the size and scale of the planned nuclear force, with some critics of the modernization plan arguing that the United States is simply replicating the Cold War force for a very different era. The second topic relates to the cost of the modernization effort, with some critics arguing that the cost is unaffordable.2 This paper begins with a review of the changes in the size and scale of U.S. nuclear forces since the Cold War. It then examines the expected costs of modernization in a comparative perspective.

Interplay of short-range correlations and nuclear symmetry energy in hard-photon production from heavy-ion reactions at Fermi energies

Science.gov (United States)

Yong, Gao-Chan; Li, Bao-An

2017-12-01

Within an isospin- and momentum-dependent transport model for nuclear reactions at intermediate energies, we investigate the interplay of the nucleon-nucleon short-range correlations (SRCs) and nuclear symmetry energy Esym(ρ ) on hard-photon spectra in collisions of several Ca isotopes on 112Sn and 124Sn targets at a beam energy of 45 MeV/nucleon. It is found that over the whole spectra of hard photons studied, effects of the SRCs overwhelm those owing to the Esym(ρ ) . The energetic photons come mostly from the high-momentum tails (HMTs) of single-nucleon momentum distributions in the target and projectile. Within the neutron-proton dominance model of SRCs based on the consideration that the tensor force acts mostly in the isosinglet and spin-triplet nucleon-nucleon interaction channel, there are equal numbers of neutrons and protons, thus a zero isospin asymmetry in the HMTs. Therefore, experimental measurements of the energetic photons from heavy-ion collisions at Fermi energies have the great potential to help us better understand the nature of SRCs without any appreciable influence by the uncertain Esym(ρ ) . These measurements will be complementary to but also have some advantages over the ongoing and planned experiments using hadronic messengers from reactions induced by high-energy electrons or protons. Because the underlying physics of SRCs and Esym(ρ ) are closely correlated, a better understanding of the SRCs will, in turn, help constrain the nuclear symmetry energy more precisely in a broad density range.

TMI-2 Lessons Learned Task Force status report and short-term recommendations

International Nuclear Information System (INIS)

1979-07-01

Review of the Three Mile Island accident by the TMI-2 Lessons Learned Task Force has disclosed a number of actions in the areas of design and analysis and plant operations that the Task Force recommends be required in the short term to provide substantial additional protection which is required for the public health and safety. All nuclear power plants in operation or in various stages of construction or licensing action are affected to varying degrees by the specific recommendations. The Task Force is continuing work in areas of general safety criteria, systems design requirements, nuclear power plant operations, and nuclear power plant licensing

Search for an intermediate-range composition-dependent force

International Nuclear Information System (INIS)

Boynton, P.E.; Crosby, D.; Ekstrom, P.; Szumilo, A.

1987-01-01

We have conducted an experiment to detect a composition-dependent force with range λ between 10 m and 1 km, and find a statistically significant effect. If interpreted as arising from a new force, this result and other recent measurementes would be consistent in strength only if the coupling were predominantly to nuclear isospin

Short- and long-range energy strategies for Japan and the world after the Fukushima nuclear accident

International Nuclear Information System (INIS)

Muraoka, K.; Wagner, F.; Yamagata, Y.; Donné, A.J.H.

2016-01-01

The accident at the Fukushima Dai-ichi nuclear power station in 2011 has caused profound effects on energy policies in Japan and worldwide. This is particularly because it occurred at the time of the growing awareness of global warming forcing measures towards decarbonised energy production, namely the use of fossil fuels has to be drastically reduced from the present level of more than 80% by 2050. A dilemma has now emerged because nuclear power, a CO 2 -free technology with proven large-scale energy production capability, lost confidence in many societies, especially in Japan and Germany. As a consequence, there is a world-wide effort now to expand renewable energies (REs), specifically photo-voltaic (PV) and wind power. However, the authors conjecture that PV and wind power can provide only up to a 40% share of the electricity production as long as sufficient storage is not available. Beyond this level, the technological (high grid power) and economic problems (large surplus production) grow. This is the result of the analysis of the growing use of REs in the electricity systems for Germany and Japan. The key element to overcome this situation is to develop suitable energy storage technologies. This is particularly necessary when electricity will become the main energy source because also transportation, process heat and heating, will be supplied by it. Facing the difficulty in replacing all fossil fuels in all countries with different technology standards, a rapid development of carbon capture and storage (CCS) might also be necessary. Therefore, for the short-range strategy up to 2050, all meaningful options have to be developed. For the long-range strategy beyond 2050, new energy sources (such as thermonuclear fusion, solar fuels and nuclear power—if inherently safe concepts will gain credibility of societies again), and large-scale energy storage systems based on novel concepts (such as large-capacity batteries and hydrogen) is required. It is acknowledged

Short- and long-range energy strategies for Japan and the world after the Fukushima nuclear accident

Science.gov (United States)

Muraoka, K.; Wagner, F.; Yamagata, Y.; Donné, A. J. H.

2016-01-01

The accident at the Fukushima Dai-ichi nuclear power station in 2011 has caused profound effects on energy policies in Japan and worldwide. This is particularly because it occurred at the time of the growing awareness of global warming forcing measures towards decarbonised energy production, namely the use of fossil fuels has to be drastically reduced from the present level of more than 80% by 2050. A dilemma has now emerged because nuclear power, a CO2-free technology with proven large-scale energy production capability, lost confidence in many societies, especially in Japan and Germany. As a consequence, there is a world-wide effort now to expand renewable energies (REs), specifically photo-voltaic (PV) and wind power. However, the authors conjecture that PV and wind power can provide only up to a 40% share of the electricity production as long as sufficient storage is not available. Beyond this level, the technological (high grid power) and economic problems (large surplus production) grow. This is the result of the analysis of the growing use of REs in the electricity systems for Germany and Japan. The key element to overcome this situation is to develop suitable energy storage technologies. This is particularly necessary when electricity will become the main energy source because also transportation, process heat and heating, will be supplied by it. Facing the difficulty in replacing all fossil fuels in all countries with different technology standards, a rapid development of carbon capture and storage (CCS) might also be necessary. Therefore, for the short-range strategy up to 2050, all meaningful options have to be developed. For the long-range strategy beyond 2050, new energy sources (such as thermonuclear fusion, solar fuels and nuclear power—if inherently safe concepts will gain credibility of societies again), and large-scale energy storage systems based on novel concepts (such as large-capacity batteries and hydrogen) is required. It is acknowledged

Pion Condensation and Alternating Layer Spin Model in Symmetric Nuclear Matter : Use of Extended Effective Nuclear Forces : Nuclear Physics

OpenAIRE

Teiji, KUNIHIRO; Tatsuyuki, TAKATSUKA; Ryozo, TAMAGAKI; Department of National Sciences, Ryukoku University; College of Humanities and Social Sciences, Iwate University; Department of Physics, Kyoto University

1985-01-01

Pion condensation in the symmetric nuclear matter is investigated on the basis of the ALS (alternating-layer-spin) model which provides a good description for the π^0 condensation. We perform energy calculations in a realistic way where the isobar (Δ)-mixing, the short range effects and the exchange energy of the interaction are taken into account. The Δ-mixing effect is built in the model state as previously done in the neutron matter. We preferentially employ G-0 force of Sprung and Banerje...

A finite range pairing force for density functional theory in superfluid nuclei

International Nuclear Information System (INIS)

Tian, Y.; Ma, Z.Y.; Ring, P.

2009-01-01

The problem of pairing in the 1 S 0 channel of finite nuclei is revisited. In nuclear matter forces of separable form can be adjusted to the bare nuclear force, to any phenomenological pairing interaction such as the Gogny force or to exact solutions of the gap equation. In finite nuclei, because of translational invariance, such forces are no longer separable. Using well-known techniques of Talmi and Moshinsky we expand the matrix elements in a series of separable terms, which converges quickly preserving translational invariance and finite range. In this way the complicated problem of a cut-off at large momenta or energies inherent in other separable or zero range pairing forces is avoided. Applications in the framework of the relativistic Hartree-Bogoliubov approach show that the pairing properties are depicted on almost the same footing as by the original pairing interaction not only in nuclear matter, but also in finite nuclei. This simple separable force can be easily applied for the investigation of pairing properties in nuclei far from stability as well as for further investigations going beyond mean field theory.

Nuclear forces

International Nuclear Information System (INIS)

Holinde, K.

1990-01-01

In this paper the present status of the meson theory of nuclear forces is reviewed. After some introductory remarks about the relevance of the meson exchange concept in the era of QCD and the empirical features of the NN interaction, the exciting history of nuclear forces is briefly outlined. In the main part, the author gives the basic physical ideas and sketch the derivation of the one-boson-exchange model of the nuclear force, in the Feynman approach. Secondly we describe, in a qualitative way, various necessary extensions, leading to the Bonn model of the N interaction. Finally, points to some interesting pen questions connected with the extended quark structure of the hadrons, which are topics of current research activity

Unitarity corrections to short-range order long-range rapidity correlations

CERN Document Server

Capella, A

1978-01-01

Although the effective hadronic forces have short range in rapidity space, one nevertheless expects long-range dynamical correlations induced by unitarity constraints. This paper contains a thorough discussion of long-range rapidity correlations in high-multiplicity events. In particular, the authors analyze in detail the forward- backward multiplicity correlations, measured recently in the whole CERN ISR energy range. They find from these data that the normalized variance of the number n of exchanged cut Pomerons, ((n/(n)-1)/sup 2/) , is most probably in the range 0.32 to 0.36. They show that such a number is obtained from Reggeon theory in the eikonal approximation. The authors also predict a very specific violation of local compensation of charge in multiparticle events: The violation should appear in the fourth-order zone correlation function and is absent in the second-order correlation function, the only one measured until now. (48 refs).

Neutrino-Nucleus Interactions and the Short-Range Structure of Nuclei

Energy Technology Data Exchange (ETDEWEB)

Cavanna, F. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Palamara, O. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Schiavilla, R. [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Soderberg, M. [Syracuse Univ., NY (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wiringa, R. B. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-01-08

Improvements in theoretical modeling of Short Range structures and phenomena, and comparisons with data, will require sustained collaboration between nuclear theorists and neutrino experimentalists. The extensive history of studying this area of nuclear physics in electron- and hadron-scattering experiments, coupled with the transformative capabilities of LArTPCs to identify neutrinos, will provide a ripe opportunity for new discoveries that will further our understanding of the nucleus.

Chiral approach to nuclear matter: Role of explicit short-range NN-terms

International Nuclear Information System (INIS)

Fritsch, S.; Kaiser, N.

2004-01-01

We extend a recent chiral approach to nuclear matter by including the most general (momentum-independent) NN-contact interaction. Iterating this two-parameter contact vertex with itself and with one-pion exchange the emerging energy per particle exhausts all terms possible up to and including fourth order in the small momentum expansion. Two (isospin-dependent) cut-offs Λ 0,1 are introduced to regularize the (linear) divergences of some three-loop in-medium diagrams. The equation of state of pure neutron matter, anti E n (k n ), can be reproduced very well up to quite high neutron densities of ρ n =0.5 fm -3 by adjusting the strength of a repulsive nn-contact interaction. Binding and saturation of isospin-symmetric nuclear matter is a generic feature of our perturbative calculation. Fixing the maximum binding energy per particle to - anti E(k f0 )=15.3 MeV we find that any possible equilibrium density ρ 0 lies below ρ 0 max =0.191 fm -3 . The additional constraint from the neutron matter equation of state leads however to a somewhat too low saturation density of ρ 0 =0.134 fm -3 . We also investigate the effects of the NN-contact interaction on the complex single-particle potential U(p,k f )+iW(p,k f ). We find that the effective nucleon mass at the Fermi surface is bounded from below by M * (k f0 ) ≥1.4 M. This property keeps the critical temperature of the liquid-gas phase transition at somewhat too high values T c ≥21 MeV. The downward bending of the asymmetry energy A(k f ) above nuclear-matter saturation density is a generic feature of the approximation to fourth order. We furthermore investigate the effects of the NN-contact interaction on the (vector-∇ρ) 2 -term in the nuclear energy density functional E[ρ,τ]. Altogether, there is within this complete fourth-order calculation no ''magic'' set of adjustable short-range parameters with which one could reproduce simultaneously and accurately all semi-empirical properties of nuclear matter. In

Ionization induced by strong electromagnetic field in low dimensional systems bound by short range forces

Energy Technology Data Exchange (ETDEWEB)

Eminov, P.A., E-mail: peminov@mail.ru [Moscow State University of Instrument Engineering and Computer Sciences, 20 Stromynka Street, Moscow 2107996 (Russian Federation); National Research University Higher School of Economics, 3/12 Bolshoy Trekhsvyatskiy pereulok, Moscow 109028 (Russian Federation)

2013-10-01

Ionization processes for a two dimensional quantum dot subjected to combined electrostatic and alternating electric fields of the same direction are studied using quantum mechanical methods. We derive analytical equations for the ionization probability in dependence on characteristic parameters of the system for both extreme cases of a constant electric field and of a linearly polarized electromagnetic wave. The ionization probabilities for a superposition of dc and low frequency ac electric fields of the same direction are calculated. The impulse distribution of ionization probability for a system bound by short range forces is found for a superposition of constant and alternating fields. The total probability for this process per unit of time is derived within exponential accuracy. For the first time the influence of alternating electric field on electron tunneling probability induced by an electrostatic field is studied taking into account the pre-exponential term.

Influence of retardation effects on photodisintegration of a quantum system bound by short-range forces

International Nuclear Information System (INIS)

Preobrazhenskii, M.A.; Golovinskii, P.A.

1996-01-01

Expressions for cross sections for multiphonon disintegration of quantum systems bound by short-range forces are obtained in the plane-wave approximation taking into account retardation effects. It is shown that, in the region of nonrelativistic energies, their contribution is factored, and the resulting universal factor is expressed for an arbitrary degree of process nonlinearity n in terms of elementary functions. Arguments of functions are determined only by the mode ω, the radiation spectrum width β, and the bound-state energy of a system. The dependence of the contribution of retardation effects on ω, β, and n is studied in detail. Analytical expressions for cross sections for multiquantum disintegration in the first nonvanishing order with respect to correlation interaction, which exactly take into account retardation effects, are obtained. It is shown that for two-quantum processes, the contribution of correlation effects is expressed in terms of a function representing an extension of dipole polarizability, whereas for n>2, it can be described in the dipole approximation

Short Range Air Defense in Army Divisions: Do We Really Need It

National Research Council Canada - National Science Library

Anderson, Charles

2000-01-01

Ever since the Soviet threat collapsed, coupled with the demonstrated, overwhelming, capability of our air forces during numerous operations in the 1990s, the relevance of the Short Range Air Defense (SHORAD...

Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

Directory of Open Access Journals (Sweden)

Adam Sweetman

2014-04-01

Full Text Available In principle, non-contact atomic force microscopy (NC-AFM now readily allows for the measurement of forces with sub-nanonewton precision on the atomic scale. In practice, however, the extraction of the often desired ‘short-range’ force from the experimental observable (frequency shift is often far from trivial. In most cases there is a significant contribution to the total tip–sample force due to non-site-specific van der Waals and electrostatic forces. Typically, the contribution from these forces must be removed before the results of the experiment can be successfully interpreted, often by comparison to density functional theory calculations. In this paper we compare the ‘on-minus-off’ method for extracting site-specific forces to a commonly used extrapolation method modelling the long-range forces using a simple power law. By examining the behaviour of the fitting method in the case of two radically different interaction potentials we show that significant uncertainties in the final extracted forces may result from use of the extrapolation method.

Angular correlation between short-range. cap alpha. particles and. gamma. quanta

Energy Technology Data Exchange (ETDEWEB)

Kul' chitskii, L A; Latyshev, G D; Bulyginskii, D G

1949-01-01

Chang (Phys. Rev. 69, 60(1946); 70, 632(1946)) has found that the intensities of short-range ..cap alpha.. rays of Po and Ra are considerably higher than the values given by the Geiger-Nuttall law. This can be explained by assuming surface vibrations of ..cap alpha..-radioactive nuclei, which produce deformations and corresponding lowerings of the potential barrier in certain directions. In this case an angular correlation should exist between the short-range ..cap alpha.. ray and the accompanying ..gamma.. quantum. The authors checked this conclusion by applying the coincidence method to the ..cap alpha.. and ..gamma.. radiations of a mixture of RdTh (/sup 228/Th) and ThC (/sup 212/Bi). Maxima of coincidence numbers occur at angles 45 and 135 deg., with lesser maxima at 0 and 180 deg. Theoretical considerations show that in cases (like the one investigated) where the nuclear spin before and after the ..cap alpha.. and ..gamma.. emissions is zero, the angular correlations are uniquely determined whatever the deformation caused by the vibration; in other cases, the correlation depends on the kind of deformation. Therefore, it would be interesting to investigate the case of Pa, whose nuclear spin is not zero and the decay exhibits intensive groups of short-range ..cap alpha.. particles.

The relations between de-alerting nuclear force and nuclear strategy

International Nuclear Information System (INIS)

Li Zhimin

2001-01-01

De-alerting nuclear force is a hot-point issue in recent years. The relations between de-alerting and strategy (including nuclear force, target doctrine and use principle et al.), stability, advanced conventional force and NMD of the United States are analyzed, the impact of de-alerting on Chinese nuclear force were discussed and the proposal of de-alerting by stages is presented

The dependence of the nuclear charge form factor on short range correlations and surface fluctuation effects

International Nuclear Information System (INIS)

Massen, S. E.; Garistov, V. P.; Grypeos, M. E.

1996-01-01

The effects of nuclear surface fluctuations on harmonic oscillator elastic charge form factor of light nuclei are investigated, simultaneously approximating the short-range correlations through a Jastrow correlation factor. Inclusion of the surface fluctuation effects within this description, by truncating the cluster expansion at the two-body part, is found to improve somewhat the fit to the elastic charge form-factor of 16 O and 40 Ca. However, the convergence of the cluster expansion is expected to deteriorate. An additional finding is that surface-fluctuation correlations produce a drastic change in the asymptotic behaviour of the point-proton form-factor, which now falls off quite slowly (i.e. as const.q -4 ) at large values of the momentum transfer q

PLA Reforms and Chinas Nuclear Forces

Science.gov (United States)

2016-10-01

Specifically, “the value and the capability of the Rocket Force should lie in the strengthening of the credible and reliable nuclear deterrence and... deterrent imply a cap on the size of nuclear forces and the missions as- signed to them.41 However, the Rocket Force could seek to capitalize on its...JFQ 83, 4th Quarter 2016 Logan 57 PLA Reforms and China’s Nuclear Forces By David C. Logan C hina is in the midst of sweeping military reforms that

Local traction force in the proximal leading process triggers nuclear translocation during neuronal migration.

Science.gov (United States)

Umeshima, Hiroki; Nomura, Ken-Ichi; Yoshikawa, Shuhei; Hörning, Marcel; Tanaka, Motomu; Sakuma, Shinya; Arai, Fumihito; Kaneko, Makoto; Kengaku, Mineko

2018-04-05

Somal translocation in long bipolar neurons is regulated by actomyosin contractile forces, yet the precise spatiotemporal sites of force generation are unknown. Here we investigate the force dynamics generated during somal translocation using traction force microscopy. Neurons with a short leading process generated a traction force in the growth cone and counteracting forces in the leading and trailing processes. In contrast, neurons with a long leading process generated a force dipole with opposing traction forces in the proximal leading process during nuclear translocation. Transient accumulation of actin filaments was observed at the dipole center of the two opposing forces, which was abolished by inhibition of myosin II activity. A swelling in the leading process emerged and generated a traction force that pulled the nucleus when nuclear translocation was physically hampered. The traction force in the leading process swelling was uncoupled from somal translocation in neurons expressing a dominant negative mutant of the KASH protein, which disrupts the interaction between cytoskeletal components and the nuclear envelope. Our results suggest that the leading process is the site of generation of actomyosin-dependent traction force in long bipolar neurons, and that the traction force is transmitted to the nucleus via KASH proteins. Copyright © 2018 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.

van der Waals forces in density functional theory: Perturbational long-range electron-interaction corrections

International Nuclear Information System (INIS)

Angyan, Janos G.; Gerber, Iann C.; Savin, Andreas; Toulouse, Julien

2005-01-01

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a 'range-separated hybrid' functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well adapted to describe van der Waals complexes, such as rare gas dimers

Making nuclei by using nuclear forces. Overwhelming power and difficulties of π mesons

International Nuclear Information System (INIS)

Toki, Hiroshi

2013-01-01

This paper is contributed to the planed title of 'Thirty Years History of The Playing Fields of Physics'. These thirty years are exactly the period while the author has devoted himself to the research and study of physics. The title is centered on the papers on experiments. He wishes, however, to write based on his experience as a theoretical physicist on the nuclear physics as it should be and in which direction to be developed. He would like to dedicate this paper to the late Professors M. Muraoka and K. Sugimoto of Osaka University. In the section 2 of 'Overwhelming Power and Difficulty of π Mesons', the fundamental pictures of '2.1 Start of the Yukawa's π Meson theory', '2.2 Mayer-Jensen's shell model', '2.3 Nambu's chiral symmetry and its spontaneous breaking' are introduced briefly. In the section 3 of 'Physics Lead by the Nuclear Forces Including π Mesons', the subsection '3.1 Phenomenological nuclear force' is taken up at first, then '3.2 Structure of D and tensor forces', '3.3 Structure of triton and three body forces', '3.4 Tensor forces in α-particles' and '3.5 Shell structure of light nuclei developed by the Argonne group' are explained successively. In section 4 of 'Tensor Best Fitting Shell-Model', problems on '4.1 Halo structure of 11 Li brought about by the tensor force' and '4.2 Strong tensor correlated Hartree-Fock theory' are explained. In section 5 of 'Nuclear Structure in the age of K computer', present and future view is given in '5.1 Nuclear forces described on Quantum Chromo Dynamics', '5.2 Present status of the nuclear structure derived on the lattice QCD', '5.3 Three-body forces created by π mesons' and '5.4 Role of K computer in nuclear physics'. In section 6 of 'Fusion of D', a new way to reconsider this problem as one of the nuclear physics is presented. In the final section 7 of 'Exciting Nuclear Physics' a short summary and memories of Professor Sugimoto are given. (S. Funahashi)

Search for a spin-dependent short-range force between nucleons with a 3He/129Xe clock-comparison experiment

International Nuclear Information System (INIS)

Tullney, Kathlynne

2014-01-01

The standard model (SM) of particle physics describes all known particles and their interactions. However, the SM leaves many issues unresolved. For example, it only includes three of the four fundamental forces and does not clarify the question why in the strong interaction CP symmetry is violated due to its non-trivial vacuum structure is predicted (Θ-term), but experimentally unverifiable. The latter one is known as the strong CP-problem of quantum chromodynamics (QCD) and is solved by the Peccei-Quinn-Weinberg-Wilczek theory. This theory predicts a new and almost massless boson which is known as the axion. The axion feebly interacts with matter and therefore it is a good candidate for cold dark matter, too. Axions are produced by the Primakoff-effect, i.e. by conversion of photons which are scattered in the electromagnetic field, e.g. of atoms. The inverse Primakoff-effect, which converts axions to photons again, can be used for direct detection of galactic, solar, or laboratory axions. Cosmological and astrophysical observations constrain the mass of the axion from a few μeV to some meV (''axion mass window''). If the axion exists, then it mediates a CP violating, spin-dependent, short-range interaction between a fermion and the spin of another fermion. By verification of this interaction, the axion can be detected indirectly. In the framework of the present thesis an experiment to search for this spindependent short-range interaction was performed in the magnetically shielded room BMSR-2 of the Physikalisch-Technische Bundesanstalt Berlin. An ultra-sensitive low-field co-magnetometer was employed which is based on the detection of free precession of 3 He and 129 Xe nuclear spins using SQUIDs as low-noise magnetic flux detectors. The two nuclear spin polarized gases are filled into a glass cell which is immersed in a low magnetic field of about B 0 = 0.35 μT with absolute field gradients in the order of pT/cm. The spin precession frequencies of 3 He and 129

Nuclear forces and chiral theories

International Nuclear Information System (INIS)

Friar, J.L.; Washington Univ., Seattle, WA

1995-01-01

Recent successes in ab initio calculations of light nuclei (A=2-6) will be reviewed and correlated with the dynamical consequences of chiral symmetry. The tractability of nuclear physics evinced by these results is evidence for that symmetry. The relative importance of three-nucleon forces, four-nucleon forces, multi-pion exchanges, and relativistic corrections will be discussed in the context of effective field theories and dimensional power counting. Isospin violation in the nuclear force will also be discussed in this context

Understanding the major uncertainties in the nuclear symmetry energy at suprasaturation densities

International Nuclear Information System (INIS)

Xu Chang; Li Baoan

2010-01-01

Within the interacting Fermi gas model for isospin asymmetric nuclear matter, effects of the in-medium three-body interaction and the two-body short-range tensor force owing to the ρ meson exchange, as well as the short-range nucleon correlation on the high-density behavior of the nuclear symmetry energy, are demonstrated respectively in a transparent way. Possible physics origins of the extremely uncertain nuclear symmetry energy at suprasaturation densities are discussed.

Theoretical Investigation of Peak-Delay Force Reduction for Caissons Exposed to Non-breaking Short-Crested Waves

DEFF Research Database (Denmark)

Burcharth, H. F.; Liu, Z.

In nature coastal structures are exposed to oblique short-crested waves. The effect of wave incident angle on total wave force on a long caisson are twofold. The one is the force reduction due to the reduction of instantaneous point pressure on the caisson, named point-pressure force reduction....... The other is the force reduction due to the fact that the peak pressures do not occur simultaneously along the caisson, named peak-delay force reduction. These two reduction effects can also be expected with short-crested waves, as the short-crestedness of waves means the spreading of wave energy over...... a range of incident angles. The peak-delay force reduction, i.e. no simultaneous peak along caisson, is of particular interest because the equipment improvement in construction enables the building of considerably long caissons. In Japan length of caissons exceeds often 100m. This paper will concentrate...

In-medium short-range dynamics of nucleons: Recent theoretical and experimental advances

Energy Technology Data Exchange (ETDEWEB)

Atti, Claudio Ciofi degli, E-mail: ciofi@pg.infn.it

2015-08-14

The investigation of in-medium short-range dynamics of nucleons, usually referred to as the study of short-range correlations (SRCs), is a key issue in nuclear and hadronic physics. As a matter of fact, even in the simplified assumption that the nucleus could be described as a system of protons and neutrons interacting via effective nucleon–nucleon (NN) interactions, several non trivial problems arise concerning the description of in-medium (NN short-range dynamics, namely: (i) the behavior of the NN interaction at short inter-nucleon distances in medium cannot be uniquely constrained by the experimental NN scattering phase shifts due to off-shell effects; (ii) by rigorous renormalization group (RG) techniques entire families of phase equivalent interactions differing in the short-range part can be derived; (iii) the in-medium NN interaction may be, in principle, different from the free one; (iv) when the short inter-nucleon separation is of the order of the nucleon size, the question arises of possible effects from quark and gluon degrees of freedom. For more than fifty years, experimental evidence of SRCs has been searched by means of various kinds of nuclear reactions, without however convincing results, mainly because the effects of SRCs arise from non observable quantities, like, e.g., the momentum distributions, and have been extracted from observable cross sections where short- and long-range effects, effects from nucleonic and non nucleonic degrees of freedom, and effects from final state interaction, could not be unambiguously separated out. Recent years, however, were witness of new progress in the field: from one side, theoretical and computational progress has allowed one to solve ab initio the many-nucleon non relativistic Schrödinger equation in terms of realistic NN interactions, obtaining realistic microscopic wave functions, unless the case of parametrized wave functions used frequently in the past, moreover the development of advanced

Electron accelerators and nuclear physics

International Nuclear Information System (INIS)

Frois, B.

1989-01-01

The operating electron accelerators and their importance in the nuclear and in the particle physics developments, are underlined. The principles of probing the nucleus by applying electron scattering techniques and the main experimental results, are summarized. In order to understand hadron interactions and the dynamics of quark confinement in nuclei, the high energy electrons must provide quantitative data on the following topics: the structure of the nucleon, the role of non nucleonic components in nuclei, the nature of short-range nucleon correlations, the origin of the short-range part of nuclear forces and the effects of the nuclear medium on quark distributions. To progress in the nuclear structure knowledge it is necessary to build a coherent strategy of accelerator developments in Europe

The falsification of Chiral Nuclear Forces

Science.gov (United States)

Ruiz Arriola, E.; Amaro, J. E.; Navarro Perez, R.

2017-03-01

Predictive power in theoretical nuclear physics has been a major concern in the study of nuclear structure and reactions. The Effective Field Theory (EFT) based on chiral expansions provides a model independent hierarchy for many body forces at long distances but their predictive power may be undermined by the regularization scheme dependence induced by the counterterms and encoding the short distances dynamics which seem to dominate the uncertainties. We analyze several examples including zero energy NN scattering or perturbative counterterm-free peripheral scattering where one would expect these methods to work best and unveil relevant systematic discrepancies when a fair comparison to the Granada-2013 NN-database and partial wave analysis (PWA) is undertaken. Work supported by Spanish Ministerio de Economia y Competitividad and European FEDER funds (grant FIS2014-59386-P), the Agencia de Innovacion y Desarrollo de Andalucia (grant No. FQM225), the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344, U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0008511 (NUCLEI SciDAC Collaboration)

Magnetic short range order in Gd

International Nuclear Information System (INIS)

Child, H.R.

1976-01-01

Quasielastic neutron scattering has been used to investigate magnetic short range order in Gd for 80 0 K 0 K. Short range order exists throughout this range from well below T/sub C/ = 291 0 K to well above it and can be reasonably well described by an anisotropic Orstein-Zernike form for chi

Tailored long range forces on polarizable particles by collective scattering of broadband radiation

International Nuclear Information System (INIS)

Holzmann, D; Ritsch, H

2016-01-01

Collective coherent light scattering by polarizable particles creates surprisingly strong, long range inter-particle forces originating from interference of the light scattered by different particles. While for monochromatic laser beams this interaction decays with the inverse distance, we show here that in general the effective interaction range and geometry can be controlled by the illumination bandwidth and geometry. As generic example we study the modifications inter-particle forces within a 1D chain of atoms trapped in the field of a confined optical nanofiber mode. For two particles we find short range attraction as well as optical binding at multiple distances. The range of stable distances shrinks with increasing light bandwidth and for a very large bandwidth field as e.g. blackbody radiation. We find a strongly attractive potential up to a critical distance beyond which the force gets repulsive. Including multiple scattering can even lead to the appearance of a stable configuration at a large distance. Such broadband scattering forces should be observable contributions in ultra-cold atom interferometers or atomic clocks setups. They could be studied in detail in 1D geometries with ultra-cold atoms trapped along or within an optical nanofiber. Broadband radiation force interactions might also contribute in astrophysical scenarios as illuminated cold dust clouds. (paper)

New concept for nuclear force: implications for nuclear structure and hadronic processes

International Nuclear Information System (INIS)

Kukulin, V.I.

2005-01-01

Full text: A new concept for nuclear force is discussed. The concept is based on idea about production of the intermediate six-quark bag (dibaryon) dressed with meson fields main of which are π-, σ-, p-, and ω-fields. The whole approach has been strongly motivated by our previous detailed analysis of various inner contradictions and inconsistencies in the conventional meson-exchange (i.e. Yukawa like) mechanism of nuclear force. The new force model predicts inevitable strong attractive 3N-force of scalar nature originated from σ-exchange between the dressed dibaryon and third nucleon. This new 3N-force has been demonstrated earlier to result in, at least, a half the total binding energy in lightest nuclei and contribute strongly to all nuclear properties like r. m. s. charge radius, nucleon momentum distribution, new electromagnetic currents and leads, very likely, to new understanding of saturation properties in nuclear matter. In the talk many other implications of the suggested new force model in hadronic and nuclear physics will be discussed

Force Triggers YAP Nuclear Entry by Regulating Transport across Nuclear Pores.

Science.gov (United States)

Elosegui-Artola, Alberto; Andreu, Ion; Beedle, Amy E M; Lezamiz, Ainhoa; Uroz, Marina; Kosmalska, Anita J; Oria, Roger; Kechagia, Jenny Z; Rico-Lastres, Palma; Le Roux, Anabel-Lise; Shanahan, Catherine M; Trepat, Xavier; Navajas, Daniel; Garcia-Manyes, Sergi; Roca-Cusachs, Pere

2017-11-30

YAP is a mechanosensitive transcriptional activator with a critical role in cancer, regeneration, and organ size control. Here, we show that force applied to the nucleus directly drives YAP nuclear translocation by decreasing the mechanical restriction of nuclear pores to molecular transport. Exposure to a stiff environment leads cells to establish a mechanical connection between the nucleus and the cytoskeleton, allowing forces exerted through focal adhesions to reach the nucleus. Force transmission then leads to nuclear flattening, which stretches nuclear pores, reduces their mechanical resistance to molecular transport, and increases YAP nuclear import. The restriction to transport is further regulated by the mechanical stability of the transported protein, which determines both active nuclear transport of YAP and passive transport of small proteins. Our results unveil a mechanosensing mechanism mediated directly by nuclear pores, demonstrated for YAP but with potential general applicability in transcriptional regulation. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined short scale roughness and surface dielectric function gradient effects on the determination of tip-sample force in atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Gusso, André, E-mail: gusso@metal.eeimvr.uff.br [Departamento de Ciências Exatas-EEIMVR, Universidade Federal Fluminense, Volta Redonda, RJ 27255-125 (Brazil)

2013-11-11

The contribution of tip roughness to the van der Waals force between an atomic force microscopy probe tip and the sample is calculated using the multilayer effective medium model, which allows us to consider the relevant case of roughness characterized by correlation length and amplitude in the nanometer scale. The effect of the surface dielectric function gradient is incorporated in the tip-sample force model. It is concluded that for rms roughness in the few nanometers range the effect of short scale tip roughness is quite significant.

Nuclear forces and quark degrees of freedom

International Nuclear Information System (INIS)

Lacombe, M.; Loiseau, B.; Vinh Mau, R.; Demetriou, P.; Pantis, C.

1999-01-01

Attempts to derive the NN forces from the quark and gluon degrees of freedom have been made so far in the framework of the nonrelativistic quark-cluster model (QCM). The justification of such a model is based on the remarkable success in describing the static properties of single hadrons. In the earlier calculations, the NN s-wave phase shifts obtained with the QCM show that the model produces repulsive NN forces at short distances, which constitutes a success for the model, but fails to provide the intermediate range attraction indispensable for binding nucleons in nuclei. This drawback is amended within the context of these models, at the expense of introducing by hand intermediate-range attraction through meson-exchange potentials between quarks or/and between nucleons (quark clusters). This procedure improves the results for the phase shifts and it is often concluded that the QCM provides a good description of the short-range (SR) part of the NN potential. In our opinion, the above procedure does not provide a rigorous test of the validity of the quark-cluster model. In order to get a clear-cut conclusion one should consider the QCM in association with an accurate and well founded model for the long-medium-range (LR+MR) forces. For these reason we study a NN interaction model which satisfies this requirement. In this model, the LR+MR parts are given by the Paris NN potential and the SR part by the QCM. The quality of the model is then tested by confronting directly its predictions with data on observables rather then, as it is usually done, with phase shifts. We compute all the observables for pp and np scattering at energies below the pion production threshold for different QCM versions corresponding to different qq interactions. The results are then compared with the existing world set data. Preliminary results show that the agreement with experiment is not good. (authors)

Nuclear reaction matrix and nuclear forces

International Nuclear Information System (INIS)

Nagata, Sinobu; Bando, Hiroharu; Akaishi, Yoshinori.

1979-01-01

An essentially exact method of solution is presented for the reaction- matrix (G-matrix) equation defined with the orthogonalized plane-wave intermediate spectrum for high-lying two-particle states. The accuracy is examined for introduced truncations and also in comparison with the Tsai-Kuo and Sauer methods. Properties of the G-matrix are discussed with emphasis on the relation with the saturation mechanism, especially overall saturation from light to heavy nuclei. Density and starting-energy dependences of the G-matrix are separately extracted and discussed. It is demonstrated that the triplet-even tensor component of the nuclear force is principally responsible for these dependences and hence for the saturation mechanism. In this context different nuclear potentials are used in the renormalized Brueckner calculation for energies of closed-shell nuclei in the harmonic oscillator basis. A semi-phenomenological ''two-body potential'' is devised so that it can reproduce the saturation energies and densities of nuclear matter and finite nuclei in the lowest-order Brueckner treatment. It is composed of a realistic N-N potential and two additional parts; one incorporates the three-body force effect and the other is assumed to embody higher-cluster correlations in G. The tensor component in the triplet-even state of this potential is enhanced by the three-body force effect. The G-matrix is represented in the effective local form and decomposed into central, LS and tensor components. (author)

Numerical challenges of short range wake field calculations

Energy Technology Data Exchange (ETDEWEB)

Lau, Thomas; Gjonaj, Erion; Weiland, Thomas [Technische Universitaet Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder (TEMF)

2011-07-01

For present and future accelerator projects with ultra short bunches the accurate and reliable calculation of short range wake fields is an important issue. However, the numerical calculation of short range wake fields is a numerical challenging task. The presentation gives an overview over the numerical challenges and techniques for short range wake field calculations. Finally, some simulation results obtained by the program PBCI developed at the TU Darmstadt are presented.

The short range effective interaction and the spectra of calcium isotopes in (f-p) space

International Nuclear Information System (INIS)

Qing-ying, Z.; Shen-wu, L.; Jian-xin, W.

1986-01-01

In this work, the authors use a new type of extremely short range interaction, the double delta interaction (DDI) to calculate the low-lying spectra of calcium isotopes /sup 41/Ca through /sup 48/Ca. The configuration space (f-p) includes configurations ( f/sub 7/2//sup n/ ) and ( f/sub 7/2//sup n-1/2p/sub 3/2/). The calculated energies are compared with experimental data for 75 levels. For comparison, they also use usual modified surface delta interaction (MSDI) to calculate the same spectra aforementioned. It is clear that the results calculated with DDI are better than with MSDI. Therefore, in the short-range effective interaction the addition of body delta force to the modified surface delta force may improve the agreement with experiment. The authors believe that the conclusion will not be changed if one enlarges the shell model space

Space Nuclear Thermal Propulsion (SNTP) Air Force facility

Science.gov (United States)

Beck, David F.

The Space Nuclear Thermal Propulsion (SNTP) Program is an initiative within the US Air Force to acquire and validate advanced technologies that could be used to sustain superior capabilities in the area or space nuclear propulsion. The SNTP Program has a specific objective of demonstrating the feasibility of the particle bed reactor (PBR) concept. The term PIPET refers to a project within the SNTP Program responsible for the design, development, construction, and operation of a test reactor facility, including all support systems, that is intended to resolve program technology issues and test goals. A nuclear test facility has been designed that meets SNTP Facility requirements. The design approach taken to meet SNTP requirements has resulted in a nuclear test facility that should encompass a wide range of nuclear thermal propulsion (NTP) test requirements that may be generated within other programs. The SNTP PIPET project is actively working with DOE and NASA to assess this possibility.

Force detection of nuclear magnetic resonance

International Nuclear Information System (INIS)

Rugar, D.; Zueger, O.; Hoen, S.; Yannoni, C.S.; Vieth, H.M.; Kendrick, R.D.

1994-01-01

Micromechanical sensing of magnetic force was used to detect nuclear magnetic resonance with exceptional sensitivity and spatial resolution. With a 900 angstrom thick silicon nitride cantilever capable of detecting subfemtonewton forces, a single shot sensitivity of 1.6 x 10 13 protons was achieved for an ammonium nitrate sample mounted on the cantilever. A nearby millimeter-size iron particle produced a 600 tesla per meter magnetic field gradient, resulting in a spatial resolution of 2.6 micrometers in one dimension. These results suggest that magnetic force sensing is a viable approach for enhancing the sensitivity and spatial resolution of nuclear magnetic resonance microimaging

Push-off forces in elite short-track speed skating.

Science.gov (United States)

van der Kruk, Eline; Reijne, Marco M; de Laat, Bjorn; Veeger, DirkJan H E J

2018-05-30

This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.

Long-range versus short-range correlations in the two-neutron transfer reaction 64Ni(18O,16O)66Ni

Science.gov (United States)

Paes, B.; Santagati, G.; Vsevolodovna, R. Magana; Cappuzzello, F.; Carbone, D.; Cardozo, E. N.; Cavallaro, M.; García-Tecocoatzi, H.; Gargano, A.; Ferreira, J. L.; Lenzi, S. M.; Linares, R.; Santopinto, E.; Vitturi, A.; Lubian, J.

2017-10-01

Recently, various two-neutron transfer studies using the (18O,16O) reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the 18O+64Ni system at 84 MeV incident energy, to the ground and first 2+ excited state of the residual 66Ni nucleus. All the experimental data were measured by the large acceptance MAGNEX spectrometer at the Instituto Nazionale di Fisica Nucleare -Laboratori Nazionali del Sud (Italy). We have performed exact finite range cross section calculations using the coupled channel Born approximation (CCBA) and coupled reaction channel (CRC) method for the sequential and direct two-neutron transfers, respectively. Moreover, this is the first time that the formalism of the microscopic interaction boson model (IBM-2) was applied to a two-neutron transfer reaction. From our results we conclude that for two-neutron transfer to the ground state of 66Ni, the direct transfer is the dominant reaction mechanism, whereas for the transfer to the first excited state of 66Ni, the sequential process dominates. A competition between long-range and short-range correlations is discussed, in particular, how the use of two different models (Shell model and IBM's) help to disentangle long- and short-range correlations.

Charge symmetry of the nuclear force as off-shell constraint

International Nuclear Information System (INIS)

Sauer, P.U.

1975-01-01

Off-shell changes are generated in the 1 S 0 nucleon-nucleon interaction using the Reid soft-core potential and unitary transformations of short range. Charge symmetry is assumed for the nuclear force. The same off-shell variations of the Reid potential are employed as the hadronic part of the proton-proton interaction and as neutron-neutron interaction. The Reid potential fits the experimental proton-proton data. It also accounts for the neutron-neutron scattering length with satisfying accuracy. The off-shell behavior of the Reid potential is varied in two different ways. First, off-shell changes consistent with the experimental proton-proton data can be selected. (auth) are performed which preserve the fit to the proton-proton data. Most transformed potentials of the type attempted here are unable to yield the correct experimental value of the neutron-neutron scattering length and have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the neutron-neutron scattering length can be selected. Second, off-shell changes are performed which leave the neutron-neutron scattering length unaltered. Transformed potentials of this type have usually been employed in nuclear-structure calculations. The potentials which exhibit large off-shell effects in nuclear structure are unable to account for the experimental proton-proton data. Their off-shell effects are therefore of no physical significance, and the potentials have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the experimental proton-proton data can be selected. (U.S.)

Kernel optimization for short-range molecular dynamics

Science.gov (United States)

Hu, Changjun; Wang, Xianmeng; Li, Jianjiang; He, Xinfu; Li, Shigang; Feng, Yangde; Yang, Shaofeng; Bai, He

2017-02-01

To optimize short-range force computations in Molecular Dynamics (MD) simulations, multi-threading and SIMD optimizations are presented in this paper. With respect to multi-threading optimization, a Partition-and-Separate-Calculation (PSC) method is designed to avoid write conflicts caused by using Newton's third law. Serial bottlenecks are eliminated with no additional memory usage. The method is implemented by using the OpenMP model. Furthermore, the PSC method is employed on Intel Xeon Phi coprocessors in both native and offload models. We also evaluate the performance of the PSC method under different thread affinities on the MIC architecture. In the SIMD execution, we explain the performance influence in the PSC method, considering the "if-clause" of the cutoff radius check. The experiment results show that our PSC method is relatively more efficient compared to some traditional methods. In double precision, our 256-bit SIMD implementation is about 3 times faster than the scalar version.

Characterizing short-range vs. long-range spatial correlations in dislocation distributions

International Nuclear Information System (INIS)

Chevy, Juliette; Fressengeas, Claude; Lebyodkin, Mikhail; Taupin, Vincent; Bastie, Pierre; Duval, Paul

2010-01-01

Hard X-ray diffraction experiments have provided evidence of a strongly heterogeneous distribution of dislocation densities along the axis of cylindrical ice single crystals oriented for basal slip in torsion creep. The dislocation arrangements showed a complex scale-invariant character, which was analyzed by means of statistical and multifractal techniques. A trend to decreasing autocorrelation of the dislocation distribution was observed as deformation proceeds. At low strain levels, long-range spatial correlations control the distribution, but short-range correlations in relation with cross-slip progressively prevail when strain increases. This trend was reproduced by a model based on field dislocation dynamics, a theory accounting for both long-range elastic interactions and short-range interactions through transport of dislocation densities.

Characterizing short-range vs. long-range spatial correlations in dislocation distributions

Energy Technology Data Exchange (ETDEWEB)

Chevy, Juliette, E-mail: juliette.chevy@gmail.com [Laboratoire de Glaciologie et Geophysique de l' Environnement-CNRS, 54 rue Moliere, 38402 St. Martin d' Heres (France)] [Laboratoire Science et Ingenierie des Materiaux et Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 St. Martin d' Heres Cedex (France); Fressengeas, Claude; Lebyodkin, Mikhail; Taupin, Vincent [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine-Metz/CNRS, Ile du Saulcy, 57045 Metz Cedex (France); Bastie, Pierre [Laboratoire de Spectrometrie Physique, BP 87, 38402 St. Martin d' Heres Cedex (France)] [Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Duval, Paul [Laboratoire de Glaciologie et Geophysique de l' Environnement-CNRS, 54 rue Moliere, 38402 St. Martin d' Heres (France)

2010-03-15

Hard X-ray diffraction experiments have provided evidence of a strongly heterogeneous distribution of dislocation densities along the axis of cylindrical ice single crystals oriented for basal slip in torsion creep. The dislocation arrangements showed a complex scale-invariant character, which was analyzed by means of statistical and multifractal techniques. A trend to decreasing autocorrelation of the dislocation distribution was observed as deformation proceeds. At low strain levels, long-range spatial correlations control the distribution, but short-range correlations in relation with cross-slip progressively prevail when strain increases. This trend was reproduced by a model based on field dislocation dynamics, a theory accounting for both long-range elastic interactions and short-range interactions through transport of dislocation densities.

The MOLDY short-range molecular dynamics package

Science.gov (United States)

Ackland, G. J.; D'Mellow, K.; Daraszewicz, S. L.; Hepburn, D. J.; Uhrin, M.; Stratford, K.

2011-12-01

We describe a parallelised version of the MOLDY molecular dynamics program. This Fortran code is aimed at systems which may be described by short-range potentials and specifically those which may be addressed with the embedded atom method. This includes a wide range of transition metals and alloys. MOLDY provides a range of options in terms of the molecular dynamics ensemble used and the boundary conditions which may be applied. A number of standard potentials are provided, and the modular structure of the code allows new potentials to be added easily. The code is parallelised using OpenMP and can therefore be run on shared memory systems, including modern multicore processors. Particular attention is paid to the updates required in the main force loop, where synchronisation is often required in OpenMP implementations of molecular dynamics. We examine the performance of the parallel code in detail and give some examples of applications to realistic problems, including the dynamic compression of copper and carbon migration in an iron-carbon alloy. Program summaryProgram title: MOLDY Catalogue identifier: AEJU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 2 No. of lines in distributed program, including test data, etc.: 382 881 No. of bytes in distributed program, including test data, etc.: 6 705 242 Distribution format: tar.gz Programming language: Fortran 95/OpenMP Computer: Any Operating system: Any Has the code been vectorised or parallelized?: Yes. OpenMP is required for parallel execution RAM: 100 MB or more Classification: 7.7 Nature of problem: Moldy addresses the problem of many atoms (of order 10 6) interacting via a classical interatomic potential on a timescale of microseconds. It is designed for problems where statistics must be gathered over a number of equivalent runs, such as

Nuclear test - The French nuclear strike force in the 21. century: challenges, ambitions and strategy

International Nuclear Information System (INIS)

Wodka-Gallien, Philippe

2014-01-01

This bibliographical note presents a book in which the author, after having recalled the history of the French nuclear force since the first nuclear test in 1960, and outlined the fact that France has been living under the protection of its own nuclear deterrence force since that date, presents the components of this nuclear strike force with its four nuclear submarines equipped to launch new generation missiles, its fifty fighter bomber aircraft equipped with the ASMP-A missile. He presents and discusses the mission of this nuclear force, discusses the relevancy of the deterrence strategy in the present context, and the significance of such a strategy for a European country like France. He wanders whether this strike force is still affordable for our country, which can be its benefits, whether this arsenal remains useful as it has been designed in the Cold War context. He also discusses the disarmament perspectives in an unsteady international environment where power and arms race logics prevail again

Magnetic short-range order in Gd

International Nuclear Information System (INIS)

Child, H.R.

1978-01-01

The magnetic short-range order in a ferromagnetic, isotopically enriched 160 Gd metal single crystal has been investigated by quasielastic scattering of 81-meV neutrons. Since Gd behaves as an S-state ion in the metal, little anisotropy is expected in its magnetic behavior. However, the data show that there is anisotropic short-range order present over a large temperature interval both above and below T/sub C/. The data have been analyzed in terms of an Ornstein-Zernike Lorentzian form with anisotropic correlation ranges. These correlation ranges as deduced from the observed data behave normally above T/sub C/ but seem to remain constant over a fairly large interval below T/sub C/ before becoming unobservable at lower temperatures. These observations suggest that the magnetic ordering in Gd may be a more complicated phenomenon than first believed

Short-range correlations in an extended time-dependent mean-field theory

International Nuclear Information System (INIS)

Madler, P.

1982-01-01

A generalization is performed of the time-dependent mean-field theory by an explicit inclusion of strong short-range correlations on a level of microscopic reversibility relating them to realistic nucleon-nucleon forces. Invoking a least action principle for correlated trial wave functions, equations of motion for the correlation functions and the single-particle model wave function are derived in lowest order of the FAHT cluster expansion. Higher order effects as well as long-range correlations are consider only to the extent to which they contribute to the mean field via a readjusted phenomenological effective two-body interaction. The corresponding correlated stationary problem is investigated and appropriate initial conditions to describe a heavy ion reaction are proposed. The singleparticle density matrix is evaluated

Nuclear demagnetisation and brute force polarisation

International Nuclear Information System (INIS)

Konter, J.A.

1976-01-01

The techniques of adiabatic demagnetization and brute force are described extensively. Special attention is paid to the thermostatic aspects and the problems caused by heat leaks and thermal barriers. Some thermometric experiments on copper are reported concerning the heat exchange between the nuclear spin system and the conduction electron system. A brute force experiment on 95 Nb yielded a nuclear magnetic moment of μ = (6.3 +- 0.1)μsub(n). A feasibility study is made on the use of PrCu 6 hyperfine enhanced paramagnet instead of the paramagnetic salt used as a intermediate cooling stage between the dilution refrigerator and the purely nuclear refrigeration stage. This will allow for experiments of long duration (one hour and more) in the sub-milli-kelvins temperature region

The evolution of Western nuclear capabilities

International Nuclear Information System (INIS)

Ball, D.; Bethe, H.A.; Blair, B.G.; Bracken, P.; Carter, A.B.; Dickinson, H.; Garwin, R.L.; Gottfried, K.; Holloway, D.; Kendall, H.W.

1988-01-01

This paper reports on the evolution of western nuclear capabilities. Presidents Truman and Eisenhower largely cast the die that determined the role, size, and organization of today's nuclear forces. The milestones were Truman's vast expansion of the nuclear weapons stockpile, followed by a series of seminal decisions by Eisenhower: transfer of peacetime civilian custody of nuclear weapons to the military; creation of a streamlined chain of command and a centrally coordinated war plan for all U.S. strategic forces; and the commitment to develop and deploy land- and submarine-based missiles of intercontinental range. The current U.S. strategic forces have some 11,000 widely dispersed nuclear warheads, of which more than 6,000 are ready for launch within minutes, can be traced back to these initiatives. Naturally, they were not taken in a geopolitical vacuum. Truman and Eisenhower had to contend with the Berlin Blockade in 1948, followed shortly thereafter by the Korean War

Landau parameters for finite range density dependent nuclear interactions

International Nuclear Information System (INIS)

Farine, M.

1997-01-01

The Landau parameters represent the effective particle-hole interaction at Fermi level. Since between the physical observables and the Landau parameters there is a direct relation their derivation from an effective interaction is of great interest. The parameter F 0 determines the incompressibility K of the system. The parameter F 1 determines the effective mass (which controls the level density at the Fermi level). In addition, F 0 ' determines the symmetry energy, G 0 the magnetic susceptibility, and G 0 ' the pion condensation threshold in nuclear matter. This paper is devoted to a general derivation of Landau parameters for an interaction with density dependent finite range terms. Particular carefulness is devoted to the inclusion of rearrangement terms. This report is part of a larger project which aims at defining a new nuclear interaction improving the well-known D1 force of Gogny et al. for describing the average nuclear properties and exotic nuclei and satisfying, in addition, the sum rules

Magnetic short range order and the exchange coupling in magnets

International Nuclear Information System (INIS)

Antropov, V.P.

2006-01-01

We discuss our recent results of time-dependent density functional simulations of magnetic properties of Fe and Ni at finite temperatures. These results indicated that a strong magnetic short range order is responsible for the magnetic properties of elementary Ni and any itinerant magnet in general. We demonstrated that one can use the value of the magnetic short range order parameter to produce new quantitative classification of magnets. We also discuss the nature of the exchange coupling and its connection with the short range order. The spin-wave like propagating and diffusive excitations in paramagnetic localized systems with small short range order have been predicted while in the itinerant systems the short range order is more complicated. The possible smallness of the quantum factor in the itinerant magnets with short range order is discussed

Short-range/Long-range Integrated Target (SLIT) for Video Guidance Sensor Rendezvous and Docking

Science.gov (United States)

Roe, Fred D. (Inventor); Bryan, Thomas C. (Inventor)

2009-01-01

A laser target reflector assembly for mounting upon spacecraft having a long-range reflector array formed from a plurality of unfiltered light reflectors embedded in an array pattern upon a hemispherical reflector disposed upon a mounting plate. The reflector assembly also includes a short-range reflector array positioned upon the mounting body proximate to the long-range reflector array. The short-range reflector array includes three filtered light reflectors positioned upon extensions from the mounting body. The three filtered light reflectors retro-reflect substantially all incident light rays that are transmissive by their monochromatic filters and received by the three filtered light reflectors. In one embodiment the short-range reflector array is embedded within the hemispherical reflector,

Recent Progress in the Theory of Nuclear Forces

International Nuclear Information System (INIS)

Machleidt, R.; MacPherson, Q.; Winzer, R.; Marji, E.; Zeoli, Ch.; Entem, D. R.

2013-01-01

During the past two decades, it has been demonstrated that chiral effective field theory represents a powerful tool to deal with nuclear forces in a systematic and model-independent way. Two-, three-, and four-nucleon forces have been derived up to next-to-next-to-next-to-leading order (N 3 LO) and (partially) applied in nuclear few- and many-body systems—with, in general, a good deal of success. This may suggest that we are finally done with the nuclear force problem; but that would be too optimistic. There are still some pretty basic open issues that have been swept under rug and, finally, need our full attention, like the proper renormalization of the two-nucleon potential. Moreover, the order-by-order convergence of the many-body force contributions is at best obscure at this time. (author)

Measurements of short-range ordering in Ni3Al

International Nuclear Information System (INIS)

Okamoto, J.K.; Ahn, C.C.

1992-01-01

This paper reports on extended electron energy-loss fine structure (EXELFS) that has been used to measure short-range ordering in Ni 3 Al. Films of fcc Ni 3 Al with suppressed short-range order synthesized by vacuum evaporation of Ni 3 Al onto room temperature substrates. EXELFS data were taken from both Al K and Ni L 23 edges. The development of short-range order was observed after the samples were annealed for various times at temperatures below 350 degrees C. Upon comparison with ab initio planewave EXELFS calculations, it was found that the Warren-Cowley short-range order parameter a(1nn) changed by about -0.1 after 210 minutes of annealing at 150 degrees C

Effect of prestress force on longitudinal vibration of bonded tendons embedded in a nuclear containment

Energy Technology Data Exchange (ETDEWEB)

Kim, Byeong Hwa, E-mail: bhkim@kyungnam.ac.k [Dept. of Civil Engineering, Kyungnam University, 449 Wolyoung, Masan, Kyungnam 631-701 (Korea, Republic of); Jang, Jung Bum, E-mail: jbjang@kepri.re.k [Nuclear Power Laboratory, Korea Electric Power Research Institute, 103-16 Munji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of); Lee, Hong Pyo, E-mail: hplee@kepri.re.k [Nuclear Power Laboratory, Korea Electric Power Research Institute, 103-16 Munji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of); Lee, Do Hyung, E-mail: dohlee@pcu.ac.k [Dept. of Civil Environmental and Railroad Engineering, Paichai University, Yonja 1 gil (439-6 Doma 2 dong), Seo-gu, Daejeon 302-735 (Korea, Republic of)

2010-06-15

In this paper, evaluation of tensile force on bonded seven-wire strand embedded in nuclear reactor containments has been nondestructively investigated. For this purpose, a total of eight prestressed concrete beam specimens with different tension force levels have been fabricated and tested in terms of using an impact pulse at one end of the strand. Subsequently, various longitudinal vibration characteristics excited by the pulse have been analyzed in detailed. In short, the present study has demonstrated that longitudinal frequency, elastic wave velocity, and elastic modulus are nonlinearly increased as the tensile force level is increased. It is thus postulated that the longitudinal vibration characteristics of the existing bonded tendons can be of promising indicators for the inspection of a tensile force loss.

Isobar configurations in nuclei and short range correlations

CERN Document Server

Weber, H J

1979-01-01

Recent results on short range correlations and isobar configurations are reviewed, and in particular a unitary version of the isobar model, coupling constants and rho -meson transition potentials, a comparison with experiments, the CERN N*-knockout from /sup 4/He, QCD and the NN interaction of short range. (42 refs).

Exclusion of nuclear forces in heavy-ion Coulomb excitation and Coulomb fission experiments

International Nuclear Information System (INIS)

Neese, R.E.; Guidry, M.W.

1982-01-01

A simple prescription for estimating the energy at which nuclear forces begin to play a role in heavy-ion Coulomb excitation and Coulomb fission experiments is presented. The method differs from most commonly used recipes in accounting for projectile and target nucleus deformation effects. Using a single adjustable parameter the formula reproduces the energy for the onset of Coulomb-nuclear interference effects for a broad range of heavy-ion systems. It is suggested that most Coulomb fission experiments which have been done involve both Coulomb and nuclear excitation processes and should more properly be termed Coulomb-nuclear fission experiments

Short range correlations in the pion s-wave self-energy of pionic atoms

OpenAIRE

Salcedo, L. L.; Holinde, K.; Oset, E.; Schütz, C.

1995-01-01

We evaluate the contribution of second order terms to the pion-nucleus s-wave optical potential of pionic atoms generated by short range nuclear correlation. The corrections are sizeable because they involve the isoscalar s-wave $\\pi N$ amplitude for half off-shell situations where the amplitude is considerably larger than the on-shell one. In addition, the s-wave optical potential is reanalyzed by looking at all the different conventional contributions together lowest order, Pauli corrected ...

Nuclear structure calculations with a sum of Sussex interaction and 3-body delta force: binding energies of closed-shell nuclei

International Nuclear Information System (INIS)

Singh, B.

1978-01-01

The Sussex matrix elements lack saturation property because of the missing short-range strong repulsion. It is demonstrated that the 3-body repulsive delta force may be used to simulate the effect of the short-range repulsion. When the delta force is added to the Sussex interaction the results are almost identical with those obtained earlier by first calculating a G-matrix from the hard core and then adding this to the old Sussex matrix elements. (author)

Quantum chromodynamics: A theory of the nuclear force

International Nuclear Information System (INIS)

Craigie, N.S.

1980-06-01

A brief outline is given of a possible theory of the nuclear force and the strong interactions between elementary particles, which is supposed responsible for nuclear matter. The theory is known as quantum chromodynamics because of its association with a new kind of nuclear charge called colour and its resemblance to quantum electrodynamics. Early ideas on the nuclear force and the emergence of the quark model and the QCD Lagrangian are described first. Then properties of this theory and the problem of quark confinement, the perturbative phase of QCD, and the non-perturbative or confinement phase of QCD and the description of hadrons and their interactions are discussed

Short-range communication system

Science.gov (United States)

Alhorn, Dean C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

2012-01-01

A short-range communication system includes an antenna, a transmitter, and a receiver. The antenna is an electrical conductor formed as a planar coil with rings thereof being uniformly spaced. The transmitter is spaced apart from the plane of the coil by a gap. An amplitude-modulated and asynchronous signal indicative of a data stream of known peak amplitude is transmitted into the gap. The receiver detects the coil's resonance and decodes same to recover the data stream.

Short-range airborne transmission of expiratory droplets between two people

DEFF Research Database (Denmark)

Liu, Li; Li, Yuguo; Nielsen, Peter Vilhelm

2017-01-01

, ventilation, and breathing mode. Under the specific set of conditions studied, we found a substantial increase in airborne exposure to droplet nuclei exhaled by the source manikin when a susceptible manikin is within about 1.5 m of the source manikin, referred to as the proximity effect. The threshold...... distance of about 1.5 m distinguishes the two basic transmission processes of droplets and droplet nuclei, that is, short-range modes and the long-range airborne route. The short-range modes include both the conventional large droplet route and the newly defined short-range airborne transmission. We thus...... reveal that transmission occurring in close proximity to the source patient includes both droplet-borne (large droplet) and short-range airborne routes, in addition to the direct deposition of large droplets on other body surfaces. The mechanisms of the droplet-borne and short-range airborne routes...

Short Range Correlations in Nuclei at Large xbj through Inclusive Quasi-Elastic Electron Scattering

Energy Technology Data Exchange (ETDEWEB)

Ye, Zhihong [Univ. of Virginia, Charlottesville, VA (United States)

2013-12-01

The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for 2H, 3He, 4He, 12C, 40Ca and 48Ca, were measured via inclusive quasi-elastic electron scattering from these nuclei in a Q2 range between 0.8 and 2.8 (GeV/c)² for x>1. The cross section ratios of heavy nuclei to 2H were extracted to study two-nucleon SRC for 1

Projected Costs of U.S. Nuclear Forces, 2017 to 2026

Science.gov (United States)

2017-02-01

amounts at roughly the same rates that costs for similar programs have grown in the past. Nuclear forces account for roughly 6 percent of the total 10...nuclear forces, some published estimates of the total costs of nuclear weapons account for the costs of several related activities. Examples include...based its estimate on historical costs of analogous programs. b. This category includes nuclear-related research and operations support activities by

Measurement of transparency ratios for protons from short-range correlated pairs

Science.gov (United States)

Hen, O.; Hakobyan, H.; Shneor, R.; Piasetzky, E.; Weinstein, L. B.; Brooks, W. K.; May-Tal Beck, S.; Gilad, S.; Korover, I.; Beck, A.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M. J.; Anefalos Pereira, S.; Arrington, J. R.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Harrison, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Munoz Camacho, C.; Mustapha, B.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pivnyuk, N.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vlassov, A.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zheng, X.; Zonta, I.

2013-05-01

Nuclear transparency, Tp (A), is a measure of the average probability for a struck proton to escape the nucleus without significant re-interaction. Previously, nuclear transparencies were extracted for quasi-elastic A (e ,e‧ p) knockout of protons with momentum below the Fermi momentum, where the spectral functions are well known. In this Letter we extract a novel observable, the transparency ratio, Tp (A) /Tp(12 C), for knockout of high-missing-momentum protons from the breakup of short-range correlated pairs (2N-SRC) in Al, Fe and Pb nuclei relative to C. The ratios were measured at momentum transfer Q2 ⩾ 1.5(GeV /c) 2 and xB ⩾ 1.2 where the reaction is expected to be dominated by electron scattering from 2N-SRC. The transparency ratios of the knocked-out protons coming from 2N-SRC breakup are 20-30% lower than those of previous results for low missing momentum. They agree with Glauber calculations and agree with renormalization of the previously published transparencies as proposed by recent theoretical investigations. The new transparencies scale as A - 1 / 3, which is consistent with dominance of scattering from nucleons at the nuclear surface.

Gauge hierarchy and long range forces

International Nuclear Information System (INIS)

Pal, P.B.; Keung, Wai-Yee; Chang, D.

1990-01-01

With the aid of simple examples, we show how a long range attractive force can arise in a gauge theory with a hierarchy. The force is due to the exchange of a Higgs boson whose mass and matter couplings are both naturally suppressed by the hierarchical mass ratio. Such bosons appear if there is an accidental global symmetry in the low-energy renormalizable Lagrangian after the high energy symmetry breaking. 6 refs

Forces and stresses in cryoturbogenerator rotor in presence of short circuit

International Nuclear Information System (INIS)

Kovarskii, M.E.; Rubinraut, A.M.; Tsyrlin, A.L.

1981-01-01

A method is presented for determining the electrodynamic forces, mechanical stresses, and strains in the shells of a cryogenic-turbogenerator cryostat in the presence of an abrupt short circuit. The physical pattern of occurrence of forces in a cryostat shell is considered for capacitive, inductive, and active armature-current cases. It is shown that in addition to the radial component, there is a tangential component of the electrodynamic forces, with the interaction of the two components governing the strength in the presence of short circuits. Results are reported for mechanical-strength calculations, based on the proposed method, for a 200 kw cryogenic turbogenerator

Task Force report

International Nuclear Information System (INIS)

Anon.

1987-01-01

The International Task Force on Prevention of Nuclear Terrorism was formed in 1985 under the auspices of the Nuclear Control Institute. This report is a consensus report of the 26 task force members - all members not necessarily agreeing on every point and all wordings, but in each case a substantial majority did agree. First, the report defines the threat, then establishes the priorities. Short-term recommendations are presented on: (1) protecting nuclear weapons; (2) protecting nuclear materials; (3) protecting nuclear facilities; (4) intelligence programs; (5) civil liberties concerns; (6) controlling nuclear transfers; (7) US - Soviet cooperation; (8) arms control initiatives; (9) convention of physical protection of nuclear material; (10) role of emergency management programs; and (11) role of the media. Brief long-term recommendations are included on (1) international measures, and (2) emerging nuclear technologies. An Appendix, Production of Nuclear Materials Usable in Weapons is presented for further consideration (without recommendations)

The INF (Intermediate-Range Nuclear Forces) Controversy: A Confluence of Foreign and Domestic Interests.

Science.gov (United States)

1986-09-01

Socialist Party, PASOK , in 1981, on a platform of withdrawing Greece from NATO and expelling US forces from Greece . 5 3 Schwartz, p. 73. 47 Turkey was...Portugal, Greece , and Turkey (Spain was not a NATO member in 1979). Basing any of the new INF weapons in Portugal would have had limited effect because...of range limitations (not - as pronounced, but similar to the IRBMs deployed in Western . Europe in the late 1950s). As for Greece , anti-Americanism

The origin of the concept of nuclear forces

International Nuclear Information System (INIS)

Brown, L.M.; Rechenberg, H.

1996-01-01

This book offers a historical development of our understanding of the fundamental theories of nuclear forces from 1932 to 1950, in order to allow present day researchers a sense of perspective. The book is divided into four parts, which relate to specific periods in the development of nuclear forces theories, and concludes by considering subsequent related developments, with particular regard to the elementary particles. The first sections describes the ideas which lead towards the goal of a unified theory of nuclear forces. Yukawa's Heavy Quantum and the Mesotron are considered in the second part. The third section looks at how the meson theory came to fit among ideas on elementary particles. The fourth section describes the growing understanding of meson physics that took place between 1939 and 1950 and how this understanding led to the discovery of the pion and the development of the Standard Model. (UK)

Short range order of selenite glasses

Czech Academy of Sciences Publication Activity Database

Neov, S.; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr

1999-01-01

Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA AV ČR KSK1010104 Keywords : short range * selenite glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.822, year: 1999

Few body problems in nuclear and particle physics

International Nuclear Information System (INIS)

Slobodrian, R.J.; Cujec, B.; Ramavataram, K.

1975-01-01

Nucleon-nucleon interactions at all energies, meson-nucleon and meson-deuteron interactions, nuclear bremsstrahlung, on-shell and off-shell interactions, final-state interactions, bound and scattering states, few-body forces, polarization phenomena, short range correlations, quasi-free scattering, composite hadron models, subnucleon structure, multiparticle and coherent production processes, break-up reactions, electrodisintegration, relativistic effects and future resources in nuclear and particle physics are discussed in relation to the state of few-body physics in 1974. (B.F.G.)

Thermodynamic properties of short-range square well fluid

Science.gov (United States)

López-Rendón, R.; Reyes, Y.; Orea, P.

2006-08-01

The interfacial properties of short-range square well fluid with λ =1.15, 1.25, and 1.375 were determined by using single canonical Monte Carlo simulations. Simulations were carried out in the vapor-liquid region. The coexistence curves of these models were calculated and compared to those previously reported in the literature and good agreement was found among them. We found that the surface tension curves for any potential model of short range form a single master curve when we plot γ* vs T /Tc. It is demonstrated that the critical reduced second virial coefficient B2* as a function of interaction range or Tc* is not constant.

Physics with radioactive nuclear beams

International Nuclear Information System (INIS)

Boyd, R.N.; Tanihata, I.

1992-01-01

Recently developed facilities allow a wide range of new investigations of the reactions and properties of short-lived nuclei. These studies may help to solve puzzles of nuclear structure and the Big Bang. The purpose of nuclear physics is to measure properties of specific nuclides and infer from them global properties common to all nuclides. One goal, for example, is to understand nuclear sizes and matter distributions in terms of basic nuclear forces. Another is to understand the variation throughout the periodic table of the dominant quantum states, which are known as the open-quotes nuclear shell modelclose quotes states and are characterized, much as are atomic states, by a principal quantum number and by orbital and total angular momentum quantum numbers. In turn other nuclear phenomena, such as the collective excitations known as giant resonances, can be understood in terms of the shell-model configurations and basic nuclear parameters. Radioactive nuclear beam studies of reactions of short-lived nuclides have already yielded results with important ramifications in both nuclear physics and astrophysics. Nuclear physicists expect unstable nuclides to exhibit unusual structures or features that may test their understanding of known nuclear phenomena at extreme conditions, and perhaps even to reveal previously unknown nuclear phenomena, Astrophysicists, for their part, have known for several decades that processes in both Big Bang nucleosynthesis and stellar nucleosynthesis involve short-lived nuclides. Indeed, the original motivation for developing radioactive nuclear beams was astrophysical. 25 refs., 7 figs

Physics with radioactive nuclear beams

International Nuclear Information System (INIS)

Boyd, R.N.

1995-01-01

Recently developed facilities allow a wide range of new investigations of the reactions and properties of short-lived nuclei. These studies may help to solve puzzles of nuclear structure and the Big Bang. The purpose of nuclear physics is to measure properties of specific nuclides and infer from them global properties common to all nuclides, for example, is to understand nuclear sizes and matter distributions in terms of basic nuclear forces. Another is to understand the variation throughout the periodic table of the dominant quantum states, which are known as the open-quotes nuclear shell model close quotes states and are characterized, much as are atomic states, by a principal quantum number and by orbital and total angular momentum quantum numbers. In turn other nuclear phenomena, such as the collective excitations known as giant resonances, can be understood in terms of the shell-model configurations and basic nuclear parameters. Radioactive nuclear beam studies of reactions of short-lived nuclides have already yielded results with important ramifications in both nuclear physics and astrophysics. Nuclear physicists expect unstable nuclides to exhibit unusual structures or features that may test their understanding of known nuclear phenomena at extreme conditions, and perhaps even to reveal previously unknown nuclear phenomena, Astrophysicists, for their part, have known for several decades that processes in both Big Bang nucleosynthesis and stellar nucleosynthesis involve short-lived nuclides. Indeed, the original motivation for developing radioactive nuclear beams was astrophysical. (author). 25 refs., 7 figs

Measured long-range repulsive Casimir-Lifshitz forces.

Science.gov (United States)

Munday, J N; Capasso, Federico; Parsegian, V Adrian

2009-01-08

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces. However, as recognized in the theories of Casimir, Polder and Lifshitz, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies. Here we show experimentally that, in accord with theoretical prediction, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir-Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction.

Problem of long-range forces in the computer simulation of condensed media

International Nuclear Information System (INIS)

Ceperely, D.

1980-07-01

Simulation (both Monte Carlo and molecular dynamical) has become a powerful tool in the study of classical systems of particles interacting with short-range pair potentials. For systems involving long-range forces (e.g., Coulombic, dipolar, hydrodynamic) it is a different story. Relating infinite-system properties to the results of computer simulation involving relatively small numbers of particles, periodically replicated, raises difficult and challenging problems. The purpose of the workshop was to bring together a group of scientists, all of whom share a strong direct interest in clearly formulating and resolving these problems. There were 46 participants, most of whom have been actively engaged in simulations of Hamiltonian models of condensed media. A few participants were scientists who are not primarily concerned, themselves, with simulation, but who are deeply involved in the theory of such models

Force-detected nuclear magnetic resonance: recent advances and future challenges.

Science.gov (United States)

Poggio, M; Degen, C L

2010-08-27

We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force between a microscopic magnet and the magnetic moments in a sample. Spurred by the recent progress in fabricating ultrasensitive force detectors, MRFM has rapidly improved its capability over the last decade. Today it boasts a spin sensitivity that surpasses conventional, inductive nuclear magnetic resonance detectors by about eight orders of magnitude. In this review we touch on the origins of this technique and focus on its recent application to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale objects with a three-dimensional (3D) spatial resolution better than 10 nm. We consider the experimental advances driving this work and highlight the underlying physical principles and limitations of the method. Finally, we discuss the challenges that must be met in order to advance the technique towards single nuclear spin sensitivity-and perhaps-to 3D microscopy of molecules with atomic resolution.

Study of nuclear medium effects on the effective interaction based on the one-boson exchange model

International Nuclear Information System (INIS)

Nakayama, K.

1985-02-01

In this work, starting from a realistic nucleon-nucleon interaction based on the one-boson exchange model for the nuclear force, we attempted a microscopic derivation of the effective interaction which may be appropriate for nuclear structure as well as for nucleon-nucleus scattering problems. Short-range correlations and medium polarization as well as relativistic effects on both particle-hole and Δ-hole interactions have been investigated. For the nucleon-nucleon case short-range correlations are basically restricted to S-states and affect mainly the central components of the effective interaction. In contrast, the Δ-nucleon interaction is essentially unaffected by short-range correlations due to the Pauli principle restrictions and the momentum mismatch between the central components of the correlation operator and the tensor component of the bare transition potential. Based on these analyses it is shown that short-range correlation effects can be summarized in a very simple correlation operator. (orig./HSI)

Methods for studying short-range order in solid binary solutions

International Nuclear Information System (INIS)

Beranger, Gerard

1969-12-01

The short range order definition and its characteristic parameters are first recalled. The different methods to study the short range order are then examined: X ray diffusion, electrical resistivity, specific heat and thermoelectric power, neutron diffraction, electron spin resonance, study of thermodynamic and mechanical properties. The theory of the X ray diffraction effects due to short range order and the subsequent experimental method are emphasized. The principal results obtained from binary Systems, by the different experimental techniques, are reported and briefly discussed. The Au-Cu, Li-Mg, Au-Ni and Cu-Zn Systems are moreover described. (author) [fr

Measured long-range repulsive Casimir–Lifshitz forces

Science.gov (United States)

Munday, J. N.; Capasso, Federico; Parsegian, V. Adrian

2014-01-01

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies1–3. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces4. However, as recognized in the theories of Casimir, Polder and Lifshitz5–7, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies8–11. Here we show experimentally that, in accord with theoretical prediction12, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir–Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction13–15. PMID:19129843

Task force for integral test of High Energy nuclear data

Energy Technology Data Exchange (ETDEWEB)

Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-11-01

According to completion of the JENDL-High Energy file for neutron nuclear cross sections up to 50 MeV, a task force for integral test of high energy nuclear data was organized to discuss a guide line for integral test activities. A status of existing differential and integral experiments and how to perform such a test were discussed in the task force. Here the purpose and outline of the task force is explained with some future problems raised in discussion among the task member. (author)

Amorphous photonic crystals with only short-range order.

Science.gov (United States)

Shi, Lei; Zhang, Yafeng; Dong, Biqin; Zhan, Tianrong; Liu, Xiaohan; Zi, Jian

2013-10-04

Distinct from conventional photonic crystals with both short- and long-range order, amorphous photonic crystals that possess only short-range order show interesting optical responses owing to their unique structural features. Amorphous photonic crystals exhibit unique light scattering and transport, which lead to a variety of interesting phenomena such as isotropic photonic bandgaps or pseudogaps, noniridescent structural colors, and light localization. Recent experimental and theoretical advances in the study of amorphous photonic crystals are summarized, focusing on their unique optical properties, artificial fabrication, bionspiration, and potential applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Parity-non-conserving nuclear forces

International Nuclear Information System (INIS)

Desplanques, B.

1979-01-01

Theoretical and phenomenological approaches to parity-non-conserving nuclear forces are reviewed. Recent developments in the calculation of weak meson-nucleon coupling constants, whose knowledge is necessary to determine theoretically the parity-non-conserving nucleon-nucleon potential, are described. The consistency of different measurements of parity-non-conserving effects is discussed and the information they provide is compared to theoretical predictions

Long range forces and limits on unparticle interactions

International Nuclear Information System (INIS)

Deshpande, N.G.; Hsu, Stephen D.H.; Jiang Jing

2008-01-01

Couplings between standard model particles and unparticles from a nontrivial scale invariant sector can lead to long range forces. If the forces couple to quantities such as baryon or lepton (electron) number, stringent limits result from tests of the gravitational inverse square law. These limits are much stronger than from collider phenomenology and astrophysics

Evolution of Soviet Theater Nuclear Forces

International Nuclear Information System (INIS)

Atkeson, E.B.

1994-01-01

Soviet theater nuclear forces were a major pillar of Soviet superpower strength, rising sharply under Krushchev in the latter 1950s to their zenith under Brezhnev twenty years later. Most recently they have begun their decline under Gorbachev, and while not yet facing extinction, may be headed for a much reduced role under the new thinking in the USSR. This paper deals with the Soviet TNF in six periods of their life: The Post-war Stalin Period (1945-1953), the Post-Stalin Period (1953-1955), The Transition Period (1955-1959), The Period of Nuclear Revolution (1960-1964), The Period of Modern TNF Planning (1965-1980), and The Period of Non-nuclear Planning (1980-1987)

Report of short term research group on environment safety in nuclear fuel cycle, 1983

International Nuclear Information System (INIS)

1984-01-01

The research group on environment safety in nuclear fuel cycle was organized in fiscal 1979 as the research group in the range of the common utilization of Yayoi, and this is the third year since it developed into the short term research group in the Nuclear Engineering Research Laboratory. The results obtained so far were summarized in three reports, UTNL-R110, 134 and 147. In this fiscal year, ''The chemistry of reprocessing'' is the subtheme, and this short term research is to be carried out. The meeting is held on March 23 and 24, 1984, in this Laboratory, and the following reports are presented. The conference on institutional stability and the disposal of nuclear and chemically toxic wastes held at MIT, the social scientific analysis of nuclear power development, the present status of reprocessing research in foreign countries, the problems based on the operation experience of actual plants, the chemistry of fuel dissolution, the chemistry of solvent extraction, reprocessing offgas treatment and problems, the chemistry of fixing Kr and I in zeolite, waste treatment in the Tokai Reprocessing Plant of Power Reactor and Nuclear Fuel Development Corp., the chemistry of actinoids, denitration process and the chemistry of MOX production, and future reprocessing research. (Kako, I.)

Chiral nucleon-nucleon forces in nuclear structure calculations

Directory of Open Access Journals (Sweden)

Coraggio L.

2016-01-01

Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.

High-Capacity Short-Range Optical Communication Links

DEFF Research Database (Denmark)

Tatarczak, Anna

Over the last decade, we have observed a tremendous spread of end-user mobile devices. The user base of a mobile application can grow or shrink by millions per day. This situation creates a pressing need for highly scalable server infrastructure; a need nowadays satisfied through cloud computing...... offered by data centers. As the popularity of cloud computing soars, the demand for high-speed, short-range data center links grows. Vertical cavity surface emitting lasers (VCSEL) and multimode fibers (MMF) prove especially well-suited for such scenarios. VCSELs have high modulation bandwidths......, we achieve 10 Gbps over 400 m and then conrm the approach in an optimized system at 25 Gbps over 300 m. The techniques described in this thesis leverage additional degrees of freedom to better utilize the available resources of short-range links. The proposed schemes enable higher speeds and longer...

Positional short-range order in the nematic phase of n BABAs

Science.gov (United States)

Usha Deniz, K.; Pepy, G.; Parette, G.; Keller, P.

1991-10-01

The positional short-range order, SRO ⊥, perpendicular to the nematic director n̂ has been studied in the fibre-type nematics, nBABAs, by neutron diffraction. SRO ⊥ is found to be dependent on other types of nematic short-range order but not on the orientational long-range order.

New look at the nuclear force

International Nuclear Information System (INIS)

Noyes, P.

1975-07-01

Nuclear force theory and calculations are discussed. It is noted that whether the quark interpretation or the vague bootstrap ideas indicated turn out to be better approximations, it is hoped that the deuteron problem is on the verge of being turned into the Bohr atom of strong interaction physics. 2 references

Miniature large range multi-axis force-torque sensor for biomechanical applications

International Nuclear Information System (INIS)

Brookhuis, R A; Sanders, R G P; Ma, K; Lammerink, T S J; De Boer, M J; Krijnen, G J M; Wiegerink, R J

2015-01-01

A miniature force sensor for the measurement of forces and moments at a human fingertip is designed and realized. Thin silicon pillars inside the sensor provide in-plane guidance for shear force measurement and provide the spring constant in normal direction. A corrugated silicon ring around the force sensitive area provides the spring constant in shear direction and seals the interior of the sensor. To detect all load components, capacitive read-out is used. A novel electrode pattern results in a large shear force sensitivity. The fingertip force sensor has a wide force range of up to 60 N in normal direction, ± 30 N in shear direction and a torque range of ± 25 N mm. (paper)

Magnetism and atomic short-range order in Ni-Rh alloys

Science.gov (United States)

Carnegie, D. W., Jr.; Claus, H.

1984-07-01

Low-field ac susceptibility measurements of Ni-Rh samples of various concentrations are presented. Giant effects of the metallurgical state on the magnetic ordering temperature are associated with changes in the degree of atomic short-range order. By careful control of this degree of short-range order, it is possible to demonstrate the existence of a spin-glass state in Ni-Rh alloys.

A short-range ensemble prediction system for southern Africa

CSIR Research Space (South Africa)

Park, R

2012-10-01

Full Text Available system for southern Africa R PARK, WA LANDMAN AND F ENGELBRECHT CSIR, PO Box 395, Pretoria, South Africa, 0001 Email: xxxxxxxxxxxxxx@csir.co.za ? www.csir.co.za INTRODUCTION This research has been conducted in order to develop a short-range ensemble... stream_source_info Park_2012.pdf.txt stream_content_type text/plain stream_size 7211 Content-Encoding ISO-8859-1 stream_name Park_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 A short-range ensemble prediction...

Analysing the Possible Ways for Short-Term Forcing Gas Turbine Engines in Auxiliary Power Unit

Directory of Open Access Journals (Sweden)

N. I. Trotskii

2016-01-01

Full Text Available Using a gas turbine energy unit as an example, the article discusses possible ways for forcing the short-term gas turbine engines (GTE. The introduction explains the need for forcing the air transport and marine GTE in specific driving conditions and offers the main methods. Then it analyzes the three main short-term forcing methods according to GTE power, namely: precompressor water injection, a short-term rise in temperature after the combustion chamber, and feeding an additional compressed air into combustion chamber from the reserve cylinders.The analysis of the water injection method to force a GTE presents the main provisions and calculation results of the cycle, as a function of engine power on the amount of water injected into compressor inlet. It is shown that with water injection into compressor inlet in an amount of 1% of the total airflow there is a 17% power increase in the compressor. It also lists the main implementation problems of this method and makes a comparison with the results of other studies on the water injection into compressor.Next, the article concerns the GTE short-term forcing method through the pre-turbine short-term increase in the gas temperature. The article presents the calculation results of the cycle as a function of the power and the fuel-flow rate on the gas temperature at the turbine inlet. It is shown that with increasing temperature by 80 degrees the engine power increases by 11.2% and requires 11% more fuel. In the analysis of this method arises an issue of thermal barrier coating on the blade surface. The article discusses the most common types of coatings and their main shortcomings. It lists the main challenges and some ways of their solving when using this method to implement the short-term forcing.The last method under consideration is GTE short-term forcing by feeding the compressed air into the combustion chamber from the additional reserve cylinders. It should be noted that this method is

Plasma wake and nuclear forces on fragmented H+ transport

International Nuclear Information System (INIS)

Barriga-Carrasco, Manuel D; Deutsch, Claude

2006-01-01

The objective of the present work is to study the target electronic and nuclear interactions produced when a H + ion traverses classical plasma matter. Electronic interactions are treated by means of the dielectric formalism while nuclear interactions are dealt within the classical dispersion theory through a Monte Carlo computer code. The interactions through plasma electronic medium among close ions are called wake forces. We checked that these forces screen the Coulomb explosions of the two fragmented protons from the same H + ion decreasing their relative distance in the analysed cases. These forces align the interproton vector along the motion direction. They also tend the two-proton energy loss to the value of two isolated protons when at early times it is rather larger. Nevertheless most parts of these wake effects cannot be corroborated experimentally as they are masked by the projectile collisions with target nuclei in our numerical experiment. These collisions cancel the screening produced by the wake forces, increasing the interproton distance even faster than for bare Coulomb explosion. Also they misalign the interproton vector along the motion direction and contribute moderately to increase the energy loss of the fragmented H + ion. These nuclear collisions effects are more significant in reducing projectile velocity

ACR-SNM Task Force on Nuclear Medicine Training: report of the task force.

Science.gov (United States)

Guiberteau, Milton J; Graham, Michael M

2011-06-01

The expansion of knowledge and technological advances in nuclear medicine and radiology require physicians to have more expertise in functional and anatomic imaging. The convergence of these two specialties into the new discipline of molecular imaging has also begun to place demands on residency training programs for additional instruction in physiology and molecular biology. These changes have unmasked weaknesses in current nuclear medicine and radiology training programs. Adding to the impetus for change are the attendant realities of the job market and uncertain employment prospects for physicians trained in nuclear medicine but not also trained in diagnostic radiology. With this background, the ACR and the Society of Nuclear Medicine convened the Task Force on Nuclear Medicine Training to define the issues and develop recommendations for resident training.

Masses of exotic calcium isotopes pin down nuclear forces

CERN Document Server

Wienholtz, F; Blaum, K; Borgmann, Ch; Breitenfeldt, M; Cakirli, R B; George, S; Herfurth, F; Holt, J D; Kowalska, M; Kreim, S; Lunney, D; Manea, V; Menéndez, J; Neidherr, D; Rosenbusch, M; Schweikhard, L; Schwenk, A; Simonis, J; Stanja, J; Wolf, R N; Zuber, K

2013-01-01

The properties of exotic nuclei on the verge of existence play a fundamental part in our understanding of nuclear interactions. Exceedingly neutron-rich nuclei become sensitive to new aspects of nuclear forces. Calcium, with its doubly magic isotopes $^{40}$Ca and $^{48}$Ca, is an ideal test for nuclear shell evolution, from the valley of stability to the limits of existence. With a closed proton shell, the calcium isotopes mark the frontier for calculations with three-nucleon forces from chiral effective field theory. Whereas predictions for the masses of $^{51}$Ca and $^{52}$Ca have been validated by direct measurements$^4$, it is an open question as to how nuclear masses evolve for heavier calcium isotopes. Here we report the mass determination of the exotic calcium isotopes $^{53}$Ca and $^{54}$Ca, using the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at CERN. The measured masses unambiguously establish a prominent shell closure at neutron number N = 32, in excellent agreement with our t...

Properties of short-range and long-range correlation energy density functionals from electron-electron coalescence

International Nuclear Information System (INIS)

Gori-Giorgi, Paola; Savin, Andreas

2006-01-01

The combination of density-functional theory with other approaches to the many-electron problem through the separation of the electron-electron interaction into a short-range and a long-range contribution is a promising method, which is raising more and more interest in recent years. In this work some properties of the corresponding correlation energy functionals are derived by studying the electron-electron coalescence condition for a modified (long-range-only) interaction. A general relation for the on-top (zero electron-electron distance) pair density is derived, and its usefulness is discussed with some examples. For the special case of the uniform electron gas, a simple parametrization of the on-top pair density for a long-range only interaction is presented and supported by calculations within the ''extended Overhauser model.'' The results of this work can be used to build self-interaction corrected short-range correlation energy functionals

Current research efforts at JILA to test the equivalence principle at short ranges

International Nuclear Information System (INIS)

Faller, J.E.; Niebauer, T.M.; McHugh, M.P.; Van Baak, D.A.

1988-01-01

We are presently engaged in three different experiments to search for a possible breakdown of the equivalence principle at short ranges. The first of these experiments, which has been completed, is our so-called Galilean test in which the differential free-fall of two objects of differing composition was measured using laser interferometry. We observed that the differential acceleration of two test bodies was less than 5 parts in 10 billion. This experiment set new limits on a suggested baryon dependent ''Fifth Force'' at ranges longer than 1 km. With a second experiment, we are investigating substance dependent interactions primarily for ranges up to 10 meters using a fluid supported torsion balance; this apparatus has been built and is now undergoing laboratory tests. Finally, a proposal has been made to measure the gravitational signal associated with the changing water level at a large pumped storage facility in Ludington, Michigan. Measuring the gravitational signal above and below the pond will yield the value of the gravitational constant, G, at ranges from 10-100 m. These measurements will serve as an independent check on other geophysical measurements of G

QCD as a basis for quark and nuclear forces

International Nuclear Information System (INIS)

Close, F.E.

1983-01-01

This chapter examines quarks in nucleons and the ideas behind the quantum chromodynamic (QCD) theory of their interactions. Compares nuclei and nucleons, and examines length or energy scales in physics. Reviews the present knowledge about the basic building blocks: quarks and leptons. Discusses color, building colorless hadrons, effects of color inside hadrons (spin flavor correlations, magnetic moments), color as the source of a field theory (molecular and nuclear forces), non-Abelian theories (qualitative features, boson-fermion vertices in SU(N), gauge invariance), renormalization and scaling violation (Lagrangians and renormalization, logs in perturbation theory), and quarks and nuclear forces

3-D Effects Force Reduction of Short-Crested Non-Breaking Waves on Caissons

DEFF Research Database (Denmark)

Burcharth, H. F.; Liu, Z.

1998-01-01

The effect of wave short-crestedness on the horizontal wave force on a caisson is twofold. The one is the force reduction due to the reduction of point pressure on the caisson, named point-pressure reduction. The other is the force reduction due to the fact that the peak pressures do not occur si...

Contribution of the covalent and the Van der Waals force to the nuclear binding

International Nuclear Information System (INIS)

Rosina, M.; Povh, B.

1994-01-01

The contribution of the covalent and the Van der Waals force to the nuclear binding is estimated in a simplified model for medium distance of about 1 fm. It is shown how colour effects suppress these two forces as compared to the case of the forces between atoms. The covalent and the Van der Waals force represent a minor though noticeable component of the nuclear force. (orig.)

Mass dependence of short-range correlations in nuclei and the EMC effect

Directory of Open Access Journals (Sweden)

Cosyn Wim

2014-03-01

Full Text Available We sketch an approximate method to quantify the number of correlated pairs in any nucleus A. It is based on counting independent-particle model (IPM nucleon-nucleon pairs in a relative S-state with no radial excitation. We show that IPM pairs with those quantum numbers are most prone to short-range correlations and are at the origin of the high-momentum tail of the nuclear momentum distributions. Our method allows to compute the a2 ratios extracted from inclusive electron scattering. Furthermore, our results reproduce the observed linear correlation between the number of correlated pairs and the magnitude of the EMC effect. We show that the width of the pair center-ofmass distribution in exclusive two-nucleon knockout yields information on the quantum numbers of the pairs.

Off-shell pairing correlations from meson-exchange theory of nuclear forces

International Nuclear Information System (INIS)

Sedrakian, Armen

2003-01-01

We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated nonperturbatively in the random phase approximation. The model is applied to the low-density neutron matter in neutron star crusts by separating the interaction into a long-range one-pion-exchange component and a short-range component parametrized in terms of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled nonlinear integral equations are solved by an iterative procedure. We find that the self-energies extend to off-shell energies of the order of several tens of MeV. At low energies the damping of the neutron pair correlations due to the coupling to the pionic modes is small, but becomes increasingly important as the energy is increased. We discuss an improved quasiclassical approximation under which the numerical solutions are obtained

Nuclear scales

Energy Technology Data Exchange (ETDEWEB)

Friar, J.L.

1998-12-01

Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the {pi}-{gamma} force), which can be calculated using chiral perturbation theory and gauged using modern phase-shift analyses. The shorter-range parts of the force are effectively parameterized by moments of the interaction that are independent of the details of the force model, in analogy to chiral perturbation theory. Results of GFMC calculations in light nuclei are interpreted in terms of fundamental scales, which are in good agreement with expectations from chiral effective field theories. Problems with spin-orbit-type observables are noted.

Nuclear scales

International Nuclear Information System (INIS)

Friar, J.L.

1998-01-01

Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the π-γ force), which can be calculated using chiral perturbation theory and gauged using modern phase-shift analyses. The shorter-range parts of the force are effectively parameterized by moments of the interaction that are independent of the details of the force model, in analogy to chiral perturbation theory. Results of GFMC calculations in light nuclei are interpreted in terms of fundamental scales, which are in good agreement with expectations from chiral effective field theories. Problems with spin-orbit-type observables are noted

Short history of nuclear many-body problem

International Nuclear Information System (INIS)

Köhler, H.S.

2014-01-01

This is a very short presentation regarding developments in the theory of nuclear many-body problems, as seen and experienced by the author during the past 60 years with particular emphasis on the contributions of Gerry Brown and his research-group. Much of his work was based on Brueckner's formulation of the nuclear many-body problem. It is reviewed briefly together with the Moszkowski–Scott separation method that was an important part of his early work. The core polarisation and his work related to effective interactions in general are also addressed

Russia's Nuclear Forces: Between Disarmament and Modernization

International Nuclear Information System (INIS)

Podvig, Pavel

2011-01-01

tactical nuclear weapons, which have not been included in arms control efforts so far. Each of these problems presents a serious challenge to Russia and the United States, especially if they maintain the emphasis on traditional Cold War notions of strategic stability and parity. However, as this analysis suggests, recent progress in nuclear disarmament and the willingness of both countries to engage in a dialogue on a range of issues give the two countries an opportunity to reduce the importance of nuclear weapons in their relationship. The paper begins with an overview of the current status of the Russian strategic nuclear forces and the strategic modernization program that is undertaken by Russia. It then considers the role that missile defense and tactical nuclear weapons could play during the next round of nuclear arms control negotiations. (author)

Applications of nuclear data on short-lived fission products

International Nuclear Information System (INIS)

Rudstam, G.; Aagaard, P.; Aleklett, K.; Lund, E.

1981-01-01

The study of short-lived fission products gives information about the nuclear structure on the neutron-rich side of stability. The data are also of interest for various applications both to basic science and to nuclear technology. Some of these applications, taken up by the OSIRIS group at Studsvik, are described in the present contribution. (orig.)

The nuclear force problem: Is the never-ending story coming to an end?

International Nuclear Information System (INIS)

Machleidt, R.

2006-01-01

The attempts to find the right (underlying) theory for the nuclear force have a long and stimulating history. Already in 1953, Hans Bethe stated that “more man-hours have been given to this problem than to any other scientific question in the history of mankind”. In search for the nature of the nuclear force, the idea of sub-nuclear particles was created which, eventually, generated the field of particle physics. I will review this productive history of hope, error, and desperation. Finally, I will discuss recent ideas which apply the concept of an effective field theory to low-energy QCD. There are indications that this concept may provide the right framework to properly understand nuclear forces.

Force majeure clauses and the threat of nuclear disaster. A Japanese case study

Energy Technology Data Exchange (ETDEWEB)

Guderian, Stephan Michael

2011-07-22

Force majeure clauses can be found in any commercial contract. Though more or less clear guidelines for the applicability of force majeure (clauses) exist in the form of international and national law, the applicability and enforceability of force majeure clauses with respect to nuclear incidents or disasters, however, remain ambiguous. Until the Japanese nuclear disaster, no major trade region was affected by any of the historical nuclear incidents. This case-study is based on the events surrounding the Tohoku earthquake, respective tsunami and nuclear incidents, especially at the Daiichi NPP and radiological contamination released there. The applicability and enforceability of force majeure clauses with their wide legal and economical implications are analyzed and evaluated according to the CISG and national domestic Japanese law. It is found that the assertion of force majeure is generally highly fact-specific and circumstance-sensitive. In general, the potential of nuclear disaster as an event triggering the force majeure defence is clearly evident, according to both international and Japanese law. Any claim must, however, be substantiated according to the principles of the different legal regimes under which the contract falls. In consequence, a company located within the evacuated areas will probably be able to successfully assert for majeure, whilst the success of any other claim will depend on the presentation of evidence, such as radiation levels and its effects in hindering performance of contractual obligations.

Force majeure clauses and the threat of nuclear disaster. A Japanese case study

International Nuclear Information System (INIS)

Guderian, Stephan Michael

2011-01-01

Force majeure clauses can be found in any commercial contract. Though more or less clear guidelines for the applicability of force majeure (clauses) exist in the form of international and national law, the applicability and enforceability of force majeure clauses with respect to nuclear incidents or disasters, however, remain ambiguous. Until the Japanese nuclear disaster, no major trade region was affected by any of the historical nuclear incidents. This case-study is based on the events surrounding the Tohoku earthquake, respective tsunami and nuclear incidents, especially at the Daiichi NPP and radiological contamination released there. The applicability and enforceability of force majeure clauses with their wide legal and economical implications are analyzed and evaluated according to the CISG and national domestic Japanese law. It is found that the assertion of force majeure is generally highly fact-specific and circumstance-sensitive. In general, the potential of nuclear disaster as an event triggering the force majeure defence is clearly evident, according to both international and Japanese law. Any claim must, however, be substantiated according to the principles of the different legal regimes under which the contract falls. In consequence, a company located within the evacuated areas will probably be able to successfully assert for majeure, whilst the success of any other claim will depend on the presentation of evidence, such as radiation levels and its effects in hindering performance of contractual obligations.

Level shifts induced by a short-range potential

International Nuclear Information System (INIS)

Karnakov, B.M.; Mur, V.D.

1984-01-01

Formulas are derived which express the shifts of levels with energies Esub(n)sup((0)) << rsub(c)sup(-2) in a field Vsub(f)(r) induced by a short-range potential U(r) of radius rsub(c) in terms of the low energy scattering parameters (scattering length and effective radius) with a moment l in the potential. If the interaction between the particle and center is nonresonant, the method developed is identical to perturbation theory on the scattering length. The theory is extended to systems with random degeneracy (Vsub(f) is the Coulomb potential). Formulas describing quasi-intersection of terms are obtained for the case of resonance interaction with the center in a partial wave with l not equal to 0 when energetically close levels are present in both U and Vsub(f). Some features of the level shift are mentioned for the case when the level possesses an anomalously small coupling energy and its coresponding wave function becomes delocalized with decrease of the coupling energy to zero. The problem is discussed of the level shift when the potential Vsub(f) is a potential well surrounded by a weaklyt penetrable barrier. Some applications of the theory to a particle in the field of two short-range potentials or in the field of a short-range and Coulomb centers are considered. Formulas are also obtained for the shifts and widths of the Landau levels and of the shallow level with an arbitrary moment which perturbs the Landau levels

Intercontinental Ballistic Missiles and their Role in Future Nuclear Forces

Science.gov (United States)

2017-05-01

while minimizing collateral damage, speed of response, and in-flight survivability. Without ICBMs, the US nuclear deterrent force would probably...September 2013. Delpech, Thérèse. Nuclear Deterrence in the 21st Century: Lessons from the Cold War for a New Era of Strategic Piracy. Santa Monica, CA...to Minimal Deterrence : A New Nuclear Policy on the Path toward Eliminating Nuclear Weapons. Occasion Paper no. 7. Washington, DC: Natural Resources

Nuclear physics with intermediate energy electrons

International Nuclear Information System (INIS)

Moniz, E.J.

1988-01-01

Nuclear physics is the study of strongly interacting matter and of the forces which govern its structure and dynamics. The goal of this paper is to give an understanding of nuclei as quantal many-body systems and of the nature of the strong force, ultimately in terms of the presumed underlying theory of quantum chromodynamics. The latter task will require a deeper understanding of hadron structure and of color confinement and, in turn, will provide the basis for exploring the structure of matter under extreme conditions, such as very high density or temperature. This program covers a very broad range of phenomena, theoretical concepts, and experimental tools and is reflected in the diverse degrees of freedom invoked in various contexts. This is indicated where degrees of freedom loosely identified with successively smaller distance scales are indicated. Very importantly, theoretical bridges have been built between the phenomenological descriptions associated with each set of degress of freedom. The mean field, determined self-consistently from the interactions of nucleons in quantum orbits, provides the basis for much of the authors microscopic understanding of nuclear structure and of our characterization of nuclear scattering processes. However, the authors are only beginning to address quantitatively the physics associated with short-range correlations, physics which takes us beyond the mean field description. The nuclear force has a very successful semi-phenomenological description in terms of hadronic degrees of freedom, both mesons and nucleon isobars. More problematic, of course, is our understanding of hadron structure and dynamics in terms of QCD

The effect of short-range spatial variability on soil sampling uncertainty

Energy Technology Data Exchange (ETDEWEB)

Perk, Marcel van der [Department of Physical Geography, Utrecht University, P.O. Box 80115, 3508 TC Utrecht (Netherlands)], E-mail: m.vanderperk@geo.uu.nl; De Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria [Agenzia per la Protezione dell' Ambiente e per i Servizi Tecnici (APAT), Servizio Laboratori, Misure ed Attivita di Campo, Via di Castel Romano, 100-00128 Roma (Italy); Fajgelj, Ales; Sansone, Umberto [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-1400 Vienna (Austria); Jeran, Zvonka; Jacimovic, Radojko [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

2008-11-15

This paper aims to quantify the soil sampling uncertainty arising from the short-range spatial variability of elemental concentrations in the topsoils of agricultural, semi-natural, and contaminated environments. For the agricultural site, the relative standard sampling uncertainty ranges between 1% and 5.5%. For the semi-natural area, the sampling uncertainties are 2-4 times larger than in the agricultural area. The contaminated site exhibited significant short-range spatial variability in elemental composition, which resulted in sampling uncertainties of 20-30%.

The effect of short-range spatial variability on soil sampling uncertainty.

Science.gov (United States)

Van der Perk, Marcel; de Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Sansone, Umberto; Jeran, Zvonka; Jaćimović, Radojko

2008-11-01

This paper aims to quantify the soil sampling uncertainty arising from the short-range spatial variability of elemental concentrations in the topsoils of agricultural, semi-natural, and contaminated environments. For the agricultural site, the relative standard sampling uncertainty ranges between 1% and 5.5%. For the semi-natural area, the sampling uncertainties are 2-4 times larger than in the agricultural area. The contaminated site exhibited significant short-range spatial variability in elemental composition, which resulted in sampling uncertainties of 20-30%.

Effects of chiral three-nucleon forces on 4He-nucleus scattering in a wide range of incident energies

Science.gov (United States)

Toyokawa, Masakazu; Yahiro, Masanobu; Matsumoto, Takuma; Kohno, Michio

2018-02-01

An important current subject is to clarify the properties of chiral three-nucleon forces (3NFs) not only in nuclear matter but also in scattering between finite-size nuclei. Particularly for elastic scattering, this study has just started and the properties are not understood for a wide range of incident energies (E_in). We investigate basic properties of chiral 3NFs in nuclear matter with positive energies by using the Brueckner-Hartree-Fock method with chiral two-nucleon forces at N3LO and 3NFs at NNLO, and analyze the effects of chiral 3NFs on 4He elastic scattering from targets ^{208}Pb, ^{58}Ni, and ^{40}Ca over a wide range of 30 ≲ E_in/A_P ≲ 200 MeV by using the g-matrix folding model, where A_P is the mass number of the projectile. In symmetric nuclear matter with positive energies, chiral 3NFs make the single-particle potential less attractive and more absorptive. The effects mainly come from the Fujita-Miyazawa 2π-exchange 3NF and become slightly larger as E_in increases. These effects persist in the optical potentials of 4He scattering. As for the differential cross sections of 4He scattering, chiral-3NF effects are large for E_in/A_P ≳ 60 MeV and improve the agreement of the theoretical results with the measured ones. Particularly for E_in/A_P ≳ 100 MeV, the folding model reproduces measured differential cross sections pretty well. Cutoff (Λ) dependence is investigated for both nuclear matter and 4He scattering by considering two cases of Λ=450 and 550 MeV. The uncertainty coming from the dependence is smaller than chiral-3NF effects even at E_in/A_P=175 MeV.

Dependability investigation of wireless short range embedded systems: hardware platform oriented approach

NARCIS (Netherlands)

Senouci, B.; Kerkhoff, Hans G.; Annema, Anne J.; Bentum, Marinus Jan

2015-01-01

A new direction in short-range wireless applications has appeared in the form of high-speed data communication devices for distances of hundreds meters. Behind these embedded applications, a complex heterogeneous architecture is built. Moreover, these short range communications are introduced into

Narrow resonances and short-range interactions

International Nuclear Information System (INIS)

Gelman, Boris A.

2009-01-01

Narrow resonances in systems with short-range interactions are discussed in an effective field theory (EFT) framework. An effective Lagrangian is formulated in the form of a combined expansion in powers of a momentum Q 0 | 0 --a resonance peak energy. At leading order in the combined expansion, a two-body scattering amplitude is the sum of a smooth background term of order Q 0 and a Breit-Wigner term of order Q 2 (δε) -1 which becomes dominant for δε 3 . Such an EFT is applicable to systems in which short-distance dynamics generates a low-lying quasistationary state. The EFT is generalized to describe a narrow low-lying resonance in a system of charged particles. It is shown that in the case of Coulomb repulsion, a two-body scattering amplitude at leading order in a combined expansion is the sum of a Coulomb-modified background term and a Breit-Wigner amplitude with parameters renormalized by Coulomb interactions.

Spin Modes in Nuclei and Nuclear Forces

International Nuclear Information System (INIS)

Suzuki, Toshio; Otsuka, Takaharu

2011-01-01

Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in 12 C and 14 C and an anomalous M1 transition in 17 C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by Δ excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

Brownian motion in short range random potentials

International Nuclear Information System (INIS)

Romero, A.H.; Romero, A.H.; Sancho, J.M.

1998-01-01

A numerical study of Brownian motion of noninteracting particles in random potentials is presented. The dynamics are modeled by Langevin equations in the high friction limit. The random potentials are Gaussian distributed and short ranged. The simulations are performed in one and two dimensions. Different dynamical regimes are found and explained. Effective subdiffusive exponents are obtained and commented on. copyright 1998 The American Physical Society

Scalable improvement of SPME multipolar electrostatics in anisotropic polarizable molecular mechanics using a general short-range penetration correction up to quadrupoles.

Science.gov (United States)

Narth, Christophe; Lagardère, Louis; Polack, Étienne; Gresh, Nohad; Wang, Qiantao; Bell, David R; Rackers, Joshua A; Ponder, Jay W; Ren, Pengyu Y; Piquemal, Jean-Philip

2016-02-15

We propose a general coupling of the Smooth Particle Mesh Ewald SPME approach for distributed multipoles to a short-range charge penetration correction modifying the charge-charge, charge-dipole and charge-quadrupole energies. Such an approach significantly improves electrostatics when compared to ab initio values and has been calibrated on Symmetry-Adapted Perturbation Theory reference data. Various neutral molecular dimers have been tested and results on the complexes of mono- and divalent cations with a water ligand are also provided. Transferability of the correction is adressed in the context of the implementation of the AMOEBA and SIBFA polarizable force fields in the TINKER-HP software. As the choices of the multipolar distribution are discussed, conclusions are drawn for the future penetration-corrected polarizable force fields highlighting the mandatory need of non-spurious procedures for the obtention of well balanced and physically meaningful distributed moments. Finally, scalability and parallelism of the short-range corrected SPME approach are addressed, demonstrating that the damping function is computationally affordable and accurate for molecular dynamics simulations of complex bio- or bioinorganic systems in periodic boundary conditions. Copyright © 2016 Wiley Periodicals, Inc.

Evolution of etched nuclear track profiles of alpha particles in CR-39 by atomic force microscopy

International Nuclear Information System (INIS)

Félix-Bautista, R.; Hernández-Hernández, C.; Zendejas-Leal, B.E.; Fragoso, R.; Golzarri, J.I.; Vázquez-López, C.; Espinosa, G.

2013-01-01

A series of atomic force microscopy (AFM) images of etched nuclear tracks has been obtained and used to calculate the nuclear track registration sensitivity parameter V(x) = Vt(x)/Vb. Due to the AFM limitations the samples were irradiated normally to the surface, and with energies attenuated in order to include the Bragg peak region in the AFM piezo-scanner z movement range. The simulation of the track profile evolution was then obtained. The different stages of etched nuclear track profiles were rendered. - Highlights: ► Using AFM we reach that Bragg peak region of etched tracks in CR-39. ► The etched track sensitivity V was calculated by data obtained by AFM. ► The evolucion of etched nuclear tracks was simulated by data achieved by AFM

Robust approach to maximize the range and accuracy of force application in atomic force microscopes with nonlinear position-sensitive detectors

International Nuclear Information System (INIS)

Silva, E C C M; Vliet, K J van

2006-01-01

The atomic force microscope is used increasingly to investigate the mechanical properties of materials via sample displacement under an applied force. However, both the extent of forces attainable and the accuracy of those forces measurements are significantly limited by the optical lever configuration that is commonly used to infer nanoscale deflection of the cantilever. We present a robust and general approach to characterize and compensate for the nonlinearity of the position-sensitive optical device via data processing, requiring no modification of existing instrumentation. We demonstrate that application of this approach reduced the maximum systematic error on the gradient of a force-displacement response from 50% to 5%, and doubled the calibrated force application range. Finally, we outline an experimental protocol that optimizes the use of the quasi-linear range of the most commonly available optical feedback configurations and also accounts for the residual systematic error, allowing the user to benefit from the full detection range of these indirect force sensors

Schroedinger operators with point interactions and short range expansions

International Nuclear Information System (INIS)

Albeverio, S.; Hoeegh-Krohn, R.; Oslo Univ.

1984-01-01

We give a survey of recent results concerning Schroedinger operators with point interactions in R 3 . In the case where the point interactions are located at a discrete set of points we discuss results about the resolvent, the spectrum, the resonances and the scattering quantities. We also discuss the approximation of point interactions by short range local potentials (short range or low energy expansions) and the one electron model of a 3-dimensional crystal. Moreover we discuss Schroedinger operators with Coulomb plus point interactions, with applications to the determination of scattering lengths and of level shifts in mesic atoms. Further applications to the multiple well problem, to multiparticle systems, to crystals with random impurities, to polymers and quantum fields are also briefly discussed. (orig.)

Evidence for short range corelations from high Q2 (e,e') reactions

International Nuclear Information System (INIS)

Strikman, M.I.; Frankfurt, L.L.; Sargayan, M.M.

1994-01-01

For many years now short-range correlations (SRC) in nuclei have been considered as an essential feature of the nuclear wave function. At high energy (e,e') reactions, where Q 2 > 1 (GeV/c) 2 , x = Q 2 /2mq o > 1 and 1 GeV > q o > 300 ∼ 400 MeV the scattering from low momentum nucleons is kinematically suppressed and there the evidence of SRC expected to be more prominent. These reactions have been intensively investigated during the last decade or so at SLAC on both light and heavy nuclei. The above kinematics allows one to compute the cross section through the processes local in space. To explain this the authors analyse the representation of the cross section as a Fourier transform of the commutator of electromagnetic currents and see that the major contribution in the cross section is given by the region of integration

Intermediate- and short-range order in phosphorus-selenium glasses

International Nuclear Information System (INIS)

Bytchkov, Aleksei; Hennet, Louis; Price, David L.; Miloshova, Mariana; Bychkov, Eugene; Kohara, Shinji

2011-01-01

State-of-the-art neutron and x-ray diffraction measurements have been performed to provide a definitive picture of the intermediate- and short-range structures of P x Se 1-x glasses spanning two glass regions, x 0.025-0.54 and 0.64-0.84. Liquid P 4 Se 3 and amorphous red P and Se were also measured. Detailed information was obtained about the development with increasing phosphorous concentration of intermediate-range order on the length scale ∼6 A ring , based on the behavior of the first sharp diffraction peak. Attention is also paid to the feature in the structure factor at 7.5 A ring -1 , identified in earlier numerical simulations, provides further evidence of the existence of molecular units. The real-space transforms yield a reliable statistical picture of the changing short-range order as x increases, using the information about types and concentrations of local structural units provided by previous NMR measurements to interpret the trends observed.

Closing the gap between short- and long-term scenarios for nuclear energy

International Nuclear Information System (INIS)

Toth, F. L.; Rogner, H.-H.

2005-01-01

Many scenarios published in recent years explore the driving forces and assess plausible ranges of global energy use and the resources they draw on. Some scenarios (e.g., OECD IEA, Organization for Economic Co-operation and Development International Energy Agency, 2004) focus on the next decade or two and project the evolution of world energy demand, supply as well as the resources, technologies, and prices to match them. Other scenarios (e.g., the Special Report on Emissions Scenarios, SRES, prepared by the Intergovernmental Panel on Climate Change, IPCC, 2000) explore the long term with a view to resource availability and depletion, technological transformations, and environmental concerns, predominantly climate change. A persistent gap (see Figure 1) can be observed in the projections for nuclear energy: near-term scenarios typically project a flat or slightly declining contribution of nuclear energy to the world energy supply whereas medium- and long-term scenarios anticipate significant increases. The magnitude of the gap between the OECD IEA (2002) projections and the median of the 40 IPCC SRES scenarios for the year 2020 amounts to almost 300 GWe installed capacity. Reasons for the gap originate in the differences between the analytical frameworks (including projection techniques) adopted by the short- and long-term studies. Another, closely related reason is the difference in the underlying assumptions, particularly their relations to recent trends and the current situation. In addition, near-term projections are heavily influenced by the social context (perceived unpopularity or outright rejection of nuclear power after Chernobyl), political factors (government pronouncements and policies at the national level, diplomacy and balancing of national positions at international organizations), economic aspects (energy market deregulation and liberalization unveiling excess capacities; financial risks), technology matters (the role of learning, definition of

Development of a quartz tuning-fork-based force sensor for measurements in the tens of nanoNewton force range during nanomanipulation experiments

Energy Technology Data Exchange (ETDEWEB)

Oiko, V. T. A., E-mail: oiko@ifi.unicamp.br; Rodrigues, V.; Ugarte, D. [Instituto de Física “Gleb Wataghin,” Univ. Estadual de Campinas (UNICAMP), Campinas 13083-859 (Brazil); Martins, B. V. C. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Silva, P. C. [Laboratório Nacional de Nanotecnologia, CNPEM, Campinas 13083-970 (Brazil)

2014-03-15

Understanding the mechanical properties of nanoscale systems requires new experimental and theoretical tools. In particular, force sensors compatible with nanomechanical testing experiments and with sensitivity in the nN range are required. Here, we report the development and testing of a tuning-fork-based force sensor for in situ nanomanipulation experiments inside a scanning electron microscope. The sensor uses a very simple design for the electronics and it allows the direct and quantitative force measurement in the 1–100 nN force range. The sensor response is initially calibrated against a nN range force standard, as, for example, a calibrated Atomic Force Microscopy cantilever; subsequently, applied force values can be directly derived using only the electric signals generated by the tuning fork. Using a homemade nanomanipulator, the quantitative force sensor has been used to analyze the mechanical deformation of multi-walled carbon nanotube bundles, where we analyzed forces in the 5–40 nN range, measured with an error bar of a few nN.

A program in medium-energy nuclear physics. Progress report, January 1, 1992--March 31, 1995

Energy Technology Data Exchange (ETDEWEB)

Berman, B.L.; Dhuga, K.S.

1994-08-01

This renewal proposal requests continued funding for our program in experimental medium-energy nuclear physics. The focus of our program remains the understanding of the short-range part of the strong interaction in the nuclear medium. In the past three years we have focused our attention ever more sharply on experiments with real tagged photons at CEBAF. We are part of the Hall-B Collaboration at CEBAF. We are co-spokespersons on two approved CEBAF experiments, Photoreactions on {sup 3}He and Photoabsorption and Photofission of Nuclei, and we are preparing another, Nondiffractive Photoproduction of the {rho} Meson with Linearly Polarized Photons, for presentation to the next CEBAF PAC. We are part of the team that is instrumenting the Photon Tagger and a high-energy tagged polarized-photon beam for Hall B; some of the instrumentation for these projects is being built at our Nuclear Detector Laboratory, under the auspices of The George Washington University Center for Nuclear Studies. Our recent measurements of pion scattering from {sup 3}H and {sup 3}He at LAMPF and of cluster knockout from few-body nuclei at NIKHEF have yielded very provocative results, showing the importance of the very light nuclei as a laboratory for quantifying important aspects of the nuclear many-body force. We look forward to expanding our studies of short-range forces in nuclei, particularly the very fight nuclei using electromagnetic probes and employing the extraordinary power of CEBAF and the CLAS.

A program in medium-energy nuclear physics. Renewal proposal and progress report August 1, 1994

International Nuclear Information System (INIS)

Berman, B.L.; Dhuga, K.S.

1994-01-01

This renewal proposal requests continued funding for our program in experimental medium-energy nuclear physics. The focus of our program remains the understanding of the short-range part of the strong interaction in the nuclear medium. In the past three years we have focused our attention ever more sharply on experiments with real tagged photons at CEBAF. We are part of the Hall-B Collaboration at CEBAF. We are co-spokespersons on two approved CEBAF experiments, Photoreactions on 3 He and Photoabsorption and Photofission of Nuclei, and we are preparing another, Nondiffractive Photoproduction of the ρ Meson with Linearly Polarized Photons, for presentation to the next CEBAF PAC. We are part of the team that is instrumenting the Photon Tagger and a high-energy tagged polarized-photon beam for Hall B; some of the instrumentation for these projects is being built at our Nuclear Detector Laboratory, under the auspices of The George Washington University Center for Nuclear Studies. Our recent measurements of pion scattering from 3 H and 3 He at LAMPF and of cluster knockout from few-body nuclei at NIKHEF have yielded very provocative results, showing the importance of the very light nuclei as a laboratory for quantifying important aspects of the nuclear many-body force. We look forward to expanding our studies of short-range forces in nuclei, particularly the very fight nuclei using electromagnetic probes and employing the extraordinary power of CEBAF and the CLAS

Geophysical Tests for Intermediate-Range Forces

Science.gov (United States)

1993-11-01

34Feeble intermediate-range Gravitation, 1989, 154. Topics: AG,T, A forces from higher dimensions", Physical Review 60. Bell J. S., Perring J. K., ൝r...M., 134 Bell J. S., 60, 61 Coleman R., 389 Beltran-Lopez V., 359 Cabibbo N., 64 Coleman R. A ., 135 Bender P. L., 540 Calafiura P., 106 Cook A . H...of Zh. Eksp. Teor. Fiz., Selen M. A ., Shoemaker F. C., Smith A . J. S., 1985,88, 1946-1949.] Topics: SD,E,+ Blackmore E. W., Bryman D. A ., Felawka L

Force control tasks with pure haptic feedback promote short-term focused attention.

Science.gov (United States)

Wang, Dangxiao; Zhang, Yuru; Yang, Xiaoxiao; Yang, Gaofeng; Yang, Yi

2014-01-01

Focused attention has great impact on our quality of life. Our learning, social skills and even happiness are closely intertwined with our capacity for focused attention. Attention promotion is replete with examples of training-induced increases in attention capability, most of which rely on visual and auditory stimulation. Pure haptic stimulation to increase attention capability is rarely found. We show that accurate force control tasks with pure haptic feedback enhance short-term focused attention. Participants were trained by a force control task in which information from visual and auditory channels was blocked, and only haptic feedback was provided. The trainees were asked to exert a target force within a pre-defined force tolerance for a specific duration. The tolerance was adaptively modified to different levels of difficulty to elicit full participant engagement. Three attention tests showed significant changes in different aspects of focused attention in participants who had been trained as compared with those who had not, thereby illustrating the role of haptic-based sensory-motor tasks in the promotion of short-term focused attention. The findings highlight the potential value of haptic stimuli in brain plasticity and serve as a new tool to extend existing computer games for cognitive enhancement.

AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training

Science.gov (United States)

Allison, Jerry D.; Clements, Jessica B.; Coffey, Charles W.; Fahey, Frederic H.; Gress, Dustin A.; Kinahan, Paul E.; Nickoloff, Edward L.; Mawlawi, Osama R.; MacDougall, Robert D.; Pizzuitello, Robert J.

2015-01-01

The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics Training. The mission of this task force was to assemble a representative group of stakeholders to: Estimate the demand for board‐certified nuclear medicine physicists in the next 5–10 years,Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, andIdentify approaches that may be considered to facilitate the training of nuclear medicine physicists. As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face‐to‐face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission. PACS number: 01.40.G‐ PMID:26699325

Coulomb systems distorted at short distances in atomic and nuclear physics

International Nuclear Information System (INIS)

Popov, V.S.

1987-01-01

In systems bound by the Coulomb interaction distorted at short distances there may appear, under certain conditions, a rearrangment of atomic spectrum (or the Zel'dovich effect). Specific features of this effect are discussed for states with an arbitrary angular momentum l (both with and without the absorption). The equation is studied which connects nuclear level shifts with the low-energy scattering parameters a l , r l . The conditions have been found under which the rearrangement of spectrum is replaced by oscillations of atomic levels. The Coulomb renormalization of scattering lengths and that of effective ranges is discussed. Some manifestations of the Zel'dovich effect in the physics of hadronic atoms and mesomolecules are considered

The Development of a Scientific Evaluation System of Force-on-Force (FOF) Exercise for Performance-based Regulation in Nuclear Security

Energy Technology Data Exchange (ETDEWEB)

Koh, Moonsung; Jung, Myungtak [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

2015-05-15

A terrorist attack or sabotage at a nuclear facility could lead result in a great amount of loss of life and social chaos, in addition to serious radiological damage. As threats have been evolved more intelligent, divergent, advanced, the international societies including IAEA encourage for all member states to establish the performance-based regulation using Forceon- Force (FOF) exercise, computer simulation. Consequently, the performance evaluation for physical protection at nuclear facilities should focus on properly reacting to threat scenarios. Physical protection should also include detecting, blocking, delaying, interrupting including the human and technical factors the adversary having malicious intention of the realistic main threat element before he accomplishes the goal based on Design Basis Threat (DBT). After the completion of the FOF evaluation system, KINAC will evaluate, and later strengthen its overall security program in response to changes in the threat environment, technological advancements, and lessons learned. As a result, substantial improvements to a nuclear facility security can be predicted. These improvements will focus on a plant security force, physical barriers, intrusion detection systems, surveillance systems, and access controls. Through the building a Force-on-Force scientific evaluation system, KINAC will establish an efficient physical protection implementation system for nuclear energy facilities.

The Development of a Scientific Evaluation System of Force-on-Force (FOF) Exercise for Performance-based Regulation in Nuclear Security

International Nuclear Information System (INIS)

Koh, Moonsung; Jung, Myungtak

2015-01-01

A terrorist attack or sabotage at a nuclear facility could lead result in a great amount of loss of life and social chaos, in addition to serious radiological damage. As threats have been evolved more intelligent, divergent, advanced, the international societies including IAEA encourage for all member states to establish the performance-based regulation using Forceon- Force (FOF) exercise, computer simulation. Consequently, the performance evaluation for physical protection at nuclear facilities should focus on properly reacting to threat scenarios. Physical protection should also include detecting, blocking, delaying, interrupting including the human and technical factors the adversary having malicious intention of the realistic main threat element before he accomplishes the goal based on Design Basis Threat (DBT). After the completion of the FOF evaluation system, KINAC will evaluate, and later strengthen its overall security program in response to changes in the threat environment, technological advancements, and lessons learned. As a result, substantial improvements to a nuclear facility security can be predicted. These improvements will focus on a plant security force, physical barriers, intrusion detection systems, surveillance systems, and access controls. Through the building a Force-on-Force scientific evaluation system, KINAC will establish an efficient physical protection implementation system for nuclear energy facilities

Guidelines for Evaluation of Canadian Forces Indoor Firing Ranges

National Research Council Canada - National Science Library

Severs, Y

1999-01-01

Indoor Firing Ranges (IFR) within DND are typically used by Canadian Forces (CF) personnel, Cadets, RCMP, and civilian organizations for firing small bore weapons in support of both operational/ occupational and recreational requirements...

Plasma wake and nuclear forces on fragmented H{sub {sup +}} transport

Energy Technology Data Exchange (ETDEWEB)

Barriga-Carrasco, Manuel D [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, E-13071 Ciudad Real (Spain); Deutsch, Claude [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France)

2006-12-15

The objective of the present work is to study the target electronic and nuclear interactions produced when a H{sub {sup +}} ion traverses classical plasma matter. Electronic interactions are treated by means of the dielectric formalism while nuclear interactions are dealt within the classical dispersion theory through a Monte Carlo computer code. The interactions through plasma electronic medium among close ions are called wake forces. We checked that these forces screen the Coulomb explosions of the two fragmented protons from the same H{sub {sup +}} ion decreasing their relative distance in the analysed cases. These forces align the interproton vector along the motion direction. They also tend the two-proton energy loss to the value of two isolated protons when at early times it is rather larger. Nevertheless most parts of these wake effects cannot be corroborated experimentally as they are masked by the projectile collisions with target nuclei in our numerical experiment. These collisions cancel the screening produced by the wake forces, increasing the interproton distance even faster than for bare Coulomb explosion. Also they misalign the interproton vector along the motion direction and contribute moderately to increase the energy loss of the fragmented H{sub {sup +}} ion. These nuclear collisions effects are more significant in reducing projectile velocity.

Report of the Secretary of Defense Task Force on DoD Nuclear Weapons Management. Phase II: Review of the DoD Nuclear Mission

National Research Council Canada - National Science Library

Schlesinger, James R; Carns, Michael P; Crouch, II, J. D; Gansler, Jacques S; Giambastiani, Jr., Edmund P; Hamre, John J; Miller, Franklin C; Williams, Christopher A; Blackwell, Jr, James A

2008-01-01

Incidents related to the Air Force's mishandling of nuclear weapons and components led to the creation of the Task Force in June 2008 to provide advice on nuclear matters for the Secretary of Defense...

Short versus long range interactions and the size of two-body weakly bound objects

International Nuclear Information System (INIS)

Lombard, R.J.; Volpe, C.

2003-01-01

Very weakly bound systems may manifest intriguing ''universal'' properties, independent of the specific interaction which keeps the system bound. An interesting example is given by relations between the size of the system and the separation energy, or scaling laws. So far, scaling laws have been investigated for short-range and long-range (repulsive) potentials. We report here on scaling laws for weakly bound two-body systems valid for a larger class of potentials, i.e. short-range potentials having a repulsive core and long-range attractive potentials. We emphasize analogies and differences between the short- and the long-range case. In particular, we show that the emergence of halos is a threshold phenomenon which can arise when the system is bound not only by short-range interactions but also by long-range ones, and this for any value of the orbital angular momentum l. These results enlarge the image of halo systems we are accustomed to. (orig.)

Impact of additional surface observation network on short range ...

Indian Academy of Sciences (India)

Stations (AWS) surface observations (temperature and moisture) on the short range forecast over the Indian ... models, which are able to resolve mesoscale fea- ... J. Earth Syst. Sci. ..... terization of the snow field in a cloud model; J. Climate.

Recent results on short-range gravity experiment

International Nuclear Information System (INIS)

Hata, Maki; Akiyama, Takashi; Ikeda, Yuki; Kawamura, Hirokazu; Narita, Keigo; Ninomiya, Kazufumi; Ogawa, Naruya; Sato, Toshiaki; Seitaibashi, Etsuko; Sekiguchi, Yuta; Tsutsui, Ryosuke; Yazawa, Kazumasa; Murata, Jiro

2009-01-01

According to the ADD model, deviation from Newton's inverse square law is expected at below sub-millimeter scale. Present study is an experimental investigation of the Newton's gravitational law at a short range scale. We have developed an experimental setup using torsion balance bar, and succeeded to confirm the inverse square law at a centimeter scale. In addition, composition dependence of gravitational constant G is also tested at the centimeter scale, motivated to test the weak equivalence principle.

Long-range dipolar order and dispersion forces in polar liquids

Science.gov (United States)

Besford, Quinn Alexander; Christofferson, Andrew Joseph; Liu, Maoyuan; Yarovsky, Irene

2017-11-01

Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is "felt" between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied. When the structural order is compared with a dipolar dispersion force that arises from local co-operative enhancement of dipole moments, a strong agreement is found. Lifshitz theory of dispersion forces was compared with the structural order, where the theory is validated for all liquids that do not have significant local dipole correlations. For liquids that do have significant local dipole correlations, specifically liquid water, Lifshitz theory underestimates the dispersion force by a factor of 5-10, demonstrating that the force that leads to the increased structure in liquid water is missed by Lifshitz theory of van der Waals forces. We apply similar correlation functions to an ionic aqueous system, where long-range order between water's dipole moment and a single chloride ion is found to exist at 20 Å of separation, revealing a long-range perturbation of water's structure by an ion. Furthermore, we found that waters within the 1st, 2nd, and 3rd solvation shells of a chloride ion exhibit significantly enhanced dipolar interactions, particularly with waters at larger distances of separation. Our results provide a link between structures, dispersion forces, and specific ion effects, which may lead to a more robust understanding of solvation.

CMOS Receiver Front-ends for Gigabit Short-Range Optical Communications

CERN Document Server

Aznar, Francisco; Calvo Lopez, Belén

2013-01-01

This book describes optical receiver solutions integrated in standard CMOS technology, attaining high-speed short-range transmission within cost-effective constraints.  These techniques support short reach applications, such as local area networks, fiber-to-the-home and multimedia systems in cars and homes. The authors show how to implement the optical front-end in the same technology as the subsequent digital circuitry, leading to integration of the entire receiver system in the same chip.  The presentation focuses on CMOS receiver design targeting gigabit transmission along a low-cost, standardized plastic optical fiber up to 50m in length.  This book includes a detailed study of CMOS optical receiver design – from building blocks to the system level. Reviews optical communications, including long-haul transmission systems and emerging applications focused on short-range; Explains necessary fundamentals, such as characteristics of a data signal, system requirements affecting receiver design and key par...

Force induced unzipping of DNA with long range correlated noise

International Nuclear Information System (INIS)

Lam, Pui-Man; Zhen, Yi

2011-01-01

We derive and solve a Fokker–Planck equation for the stationary distribution of the free energy, in a model of unzipping of double-stranded DNA under external force. The autocorrelation function of the random DNA sequence can be of a general form, including long range correlations. In the case of Ornstein–Uhlenbeck noise, characterized by a finite correlation length, our result reduces to the exact result of Allahverdyan et al, with the average number of unzipped base pairs going as (X) ∼ 1/f 2 in the white noise limit, where f is the deviation from the critical force. In the case of long range correlated noise, where the integrated autocorrelation is divergent, we find that (X) is finite at f = 0, with its value decreasing as the correlations become of longer range. This shows that long range correlations actually stabilize the DNA sequence against unzipping. Our result is also in agreement with the findings of Allahverdyan et al obtained using numerical generation of the long range correlated noise

A new equation of state for core-collapse supernovae based on realistic nuclear forces and including a full nuclear ensemble

International Nuclear Information System (INIS)

Furusawa, S; Togashi, H; Nagakura, H; Sumiyoshi, K; Yamada, S; Suzuki, H; Takano, M

2017-01-01

We have constructed a nuclear equation of state (EOS) that includes a full nuclear ensemble for use in core-collapse supernova simulations. It is based on the EOS for uniform nuclear matter that two of the authors derived recently, applying a variational method to realistic two- and three-body nuclear forces. We have extended the liquid drop model of heavy nuclei, utilizing the mass formula that accounts for the dependences of bulk, surface, Coulomb and shell energies on density and/or temperature. As for light nuclei, we employ a quantum-theoretical mass evaluation, which incorporates the Pauli- and self-energy shifts. In addition to realistic nuclear forces, the inclusion of in-medium effects on the full ensemble of nuclei makes the new EOS one of the most realistic EOSs, which covers a wide range of density, temperature and proton fraction that supernova simulations normally encounter. We make comparisons with the FYSS EOS, which is based on the same formulation for the nuclear ensemble but adopts the relativistic mean field theory with the TM1 parameter set for uniform nuclear matter. The new EOS is softer than the FYSS EOS around and above nuclear saturation densities. We find that neutron-rich nuclei with small mass numbers are more abundant in the new EOS than in the FYSS EOS because of the larger saturation densities and smaller symmetry energy of nuclei in the former. We apply the two EOSs to 1D supernova simulations and find that the new EOS gives lower electron fractions and higher temperatures in the collapse phase owing to the smaller symmetry energy. As a result, the inner core has smaller masses for the new EOS. It is more compact, on the other hand, due to the softness of the new EOS and bounces at higher densities. It turns out that the shock wave generated by core bounce is a bit stronger initially in the simulation with the new EOS. The ensuing outward propagations of the shock wave in the outer core are very similar in the two simulations, which

Short-range order in amorphous thin films of indium selenides

International Nuclear Information System (INIS)

Zakharov, V.P.; Poltavtsev, Yu.G.; Sheremet, G.P.

1982-01-01

A structure of the short-range order and a character of interatomic interactions in indium selenides Insub(1-x)Sesub(x) with 0.333 <= x <= 0.75, obtained in the form of amorphous films 0.05-0.80 μm thick are studied using electron diffraction method. It is found out that mostly tetrahedrical coordination of nearest neighbours in the vicinity of indium atoms is characteristic for studied amorphous films, and coordination of selenium atoms is different. Amorphous film with x=0.75 posesses a considereably microheterogeneous structure of the short-range order, which is characterized by the presence of microunclusions of amorphous selenium and atoms of indium, octohedrically coordinated by selenium atoms

Short-range wireless communication fundamentals of RF system design and application

CERN Document Server

Bensky, Alan

2004-01-01

The Complete "Tool Kit” for the Hottest Area in RF/Wireless Design!Short-range wireless-communications over distances of less than 100 meters-is the most rapidly growing segment of RF/wireless engineering. Alan Bensky is an internationally recognized expert in short-range wireless, and this new edition of his bestselling book is completely revised to cover the latest developments in this fast moving field.You'll find coverage of such cutting-edge topics as: architectural trends in RF/wireless integrated circuits compatibility and conflict issues between differen

Double scattering of light from Biophotonic Nanostructures with short-range order

Energy Technology Data Exchange (ETDEWEB)

Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O.; Mochrie, Simon G.J.; Dufresne, Eric R.; Cao, Hui (Yale)

2010-07-28

We investigate the physical mechanism for color production by isotropic nanostructures with short-range order in bird feather barbs. While the primary peak in optical scattering spectra results from constructive interference of singly-scattered light, many species exhibit secondary peaks with distinct characteristic. Our experimental and numerical studies show that these secondary peaks result from double scattering of light by the correlated structures. Without an analog in periodic or random structures, such a phenomenon is unique for short-range ordered structures, and has been widely used by nature for non-iridescent structural coloration.

Fluctuations in substitution type alloys and their analyses. Short-range order structures

International Nuclear Information System (INIS)

Iwasaki, Hiroshi; Ohshima, Ken-ichi

2010-01-01

This article is the fifth of the serial lecture, microstructures and fluctuations, in this magazine. The formula of X-ray diffuse scattering intensity was derived for binary alloys by introducing short-range order parameters. Diffuse scattering intensities for a single crystal Cu 3 Au were measured above critical temperature for ordering. The short-range parameters were obtained by a three-dimensional Fourier analysis. The long-range pair interaction between atoms was originated from the indirect screening interaction due to conduction electrons. A detailed study was made on short-range-order diffuse scattering from Cu 3 Au in the disordered state by electron diffraction. Fourfold splitting of the diffuse scattering was observed at 110 in the reciprocal lattice, and this result was attributed to the reflection of the form of the Fermi surface. The X-ray diffuse scattering intensity was measured at room temperature for disordered Cu-Pd alloys for the six composition of Pd. Twofold and fourfold splitting of diffuse scattering due to the short-range order (SRO) were observed at 100, 110 and equivalent positions respectively from alloys with more than 13.0at% Pd. The SRO parameters were determined from all the six alloys. For Cu-Pt alloys, the diffuse scattering originated from the correlation between Cu and Pt layers in direction was observed in addition to the one due to the reflection of the Fermi surface imaging. (author)

A New Theoretical Analysis of the Effects of Short Range Correlations in Inclusive Lepton Scattering

Science.gov (United States)

Benedetta Mezzetti, Chiara; Ciofi Degli Atti, Claudio

2009-05-01

Recently, evidence of short range correlations (SRC) has been provided by experimental data on inclusive lepton A(e, e')X scattering by the observation of a scaling behavior of the ratios of the cross sections on heavy nuclei to those on the deuteron and ^3He. Other attempts to get information on SRC rely on the concept of Y-scaling, whose interest has been renewed by new Jlab data. A new approach to Y-scaling, relying on the definition of a new relativistic scaling variable which incorporates the momentum dependence of the excitation energy of the (A - 1) system is presented, with the resulting scaling function being closely related to the longitudinal momentum distributions. Taking into account final state interaction effects, the new analysis of experimental data on nuclei, ranging from ^3He to Nuclear Matter, provides unique information on the nucleon momentum distributions and confirms the analysis in terms of cross section ratios.

Nuclear Structure of the Heaviest Elements – Investigated at SHIP-GSI

Directory of Open Access Journals (Sweden)

Heßberger Fritz Peter

2014-03-01

Full Text Available The quest for the heaviest nuclei that can exist is a basic topic in natural science as their stability is characterized by a delicate interplay of short range nuclear forces acting between the nucleons (protons and neutrons and long-range Coulomb forces acting solely between charged particles, i.e. the protons. As the stability of a nucleus is strongly correlated to its structure, understanding the nuclear structure of heaviest nuclei is presently a main challenge of experimental and theoretical investigations concerning the field of Superheavy Elements. At the velocity filter SHIP at GSI Darmstadt an extensive program on nuclear structure investigations has been started about a decade ago. The project covered both as well systematic investigations of single particle levels in odd-mass isotopes populated by α-decay as investigation of two- or fourquasi-particle states forming K isomers and was supplemented by direct mass measurements at SHIPTRAP and investigation of spontaneous fission properties. Recent experimental studies allowed to extend the systematics of low lying levels in N = 151 and N = 153 up to 255Rf and 259Sg, investigation of possible relations between nuclear structure and fission properties of odd-mass nuclei and investigation of shell strengths at N = 152 and towards N = 162.

Variational method for infinite nuclear matter with noncentral forces

International Nuclear Information System (INIS)

Takano, M.; Yamada, M.

1998-01-01

Approximate energy expressions are proposed for infinite zero-temperature nuclear matter by taking into account noncentral forces. They are explicitly expressed as functionals of spin- (isospin-) dependent radial distribution functions, tensor distribution functions and spin-orbit distribution functions, and can be used conveniently in the variational method. A notable feature of these expressions is that they automatically guarantee the necessary conditions on the spin-isospin-dependent structure functions. The Euler-Lagrange equations are derived from these energy expressions and numerically solved for neutron matter and symmetric nuclear matter. The results show that the noncentral forces bring down the total energies too much with too dense saturation densities. Since the main reason for these undesirable results seems to be the long tails of the noncentral distribution functions, an effective theory is proposed by introducing a density-dependent damping function into the noncentral potentials to suppress the long tails of the non-central distribution functions. By adjusting the value of a parameter included in the damping function, we can reproduce the saturation point (both the energy and density) of symmetric nuclear matter with the Hamada-Johnston potential. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

A short history of the CANDU nuclear power system

Energy Technology Data Exchange (ETDEWEB)

Brooks, G L

1993-04-01

This paper provides a short historical summary of the evolution of the CANDU nuclear power system with emphasis on the roles played by Ontario Hydro and private sector companies in Ontario in collaboration with Atomic Energy of Canada Limited (AECL). (author). 1 fig., 61 refs.

A short history of the CANDU nuclear power system

International Nuclear Information System (INIS)

Brooks, G.L.

1993-04-01

This paper provides a short historical summary of the evolution of the CANDU nuclear power system with emphasis on the roles played by Ontario Hydro and private sector companies in Ontario in collaboration with Atomic Energy of Canada Limited (AECL). (author). 1 fig., 61 refs

Can Sweden be forced to manage nuclear waste from other countries?

International Nuclear Information System (INIS)

Bergstroem, Ulf; Lindgren, Jonas; Nordfors, Lennart; Hallerby, Christer

2005-06-01

This report tries to answer two questions: Can Sweden, through supranational decisions, be forced to dispose of other nations nuclear waste within its own borders? and How can a Swedish stakeholder follow and influence EU-agendas, in particular concerning nuclear waste? Sometimes it has been argued that, through the EU-membership, Sweden could be forced to accept foreign radioactive waste for disposal in Sweden. However, the Swedish Nuclear Technology Act clearly states that license for final disposal spent nuclear fuels can not be given for fuel from another country than Sweden. At the Swedish EU entry it was found that the national legislation were compatible with the EU regulations, and as a consequence waste from foreign nuclear plants can not be disposed of in Sweden, even if the plant is owned by a Swedish company. Other conclusions in the report are: The system for decision making in EU is complex and slow and must be supported by supranational and international organs. The process is complex, but offers many opportunities for following-up and influencing. The risk for anything happening 'over-night' in the radioactive waste question is minimal. The issue of regulating radioactive waste management in a supranational way, i.e. by forcing a country to accept wastes from another country is not on the agenda. The Euratom treaty is interpreted in the way that such decision can not be made. The international discussions about regional repositories build upon voluntary agreements. Scenarios leading to coersive legislation are judged to be politically unrealistic - and needing important changes to be realised

Statistical Short-Range Guidance for Peak Wind Speed Forecasts on Kennedy Space Center/Cape Canaveral Air Force Station: Phase I Results

Science.gov (United States)

Lambert, Winifred C.; Merceret, Francis J. (Technical Monitor)

2002-01-01

This report describes the results of the ANU's (Applied Meteorology Unit) Short-Range Statistical Forecasting task for peak winds. The peak wind speeds are an important forecast element for the Space Shuttle and Expendable Launch Vehicle programs. The Keith Weather Squadron and the Spaceflight Meteorology Group indicate that peak winds are challenging to forecast. The Applied Meteorology Unit was tasked to develop tools that aid in short-range forecasts of peak winds at tower sites of operational interest. A 7 year record of wind tower data was used in the analysis. Hourly and directional climatologies by tower and month were developed to determine the seasonal behavior of the average and peak winds. In all climatologies, the average and peak wind speeds were highly variable in time. This indicated that the development of a peak wind forecasting tool would be difficult. Probability density functions (PDF) of peak wind speed were calculated to determine the distribution of peak speed with average speed. These provide forecasters with a means of determining the probability of meeting or exceeding a certain peak wind given an observed or forecast average speed. The climatologies and PDFs provide tools with which to make peak wind forecasts that are critical to safe operations.

The Defense Science Board Permanent Task Force on Nuclear Weapons Surety. Report on the Unauthorized Movement of Nuclear Weapons

National Research Council Canada - National Science Library

Welch, Larry D; Agnew, Harold M; Bien, Lyle G; Crawford, John C; Foster, Jr., John S; Gold, Sydell P; McCarthy, James P; Mies, Richard W; Neary, Thomas H; Selden, Robert L

2008-01-01

...]) and the Commander, U.S. Strategic Command to conduct an independent investigation of the unauthorized transfer of nuclear warheads between Minot Air Force Base, North Dakota, and Barksdale Air Force Base, Louisiana on 30 August 2007...

Nonlocality and short-range wetting phenomena.

Science.gov (United States)

Parry, A O; Romero-Enrique, J M; Lazarides, A

2004-08-20

We propose a nonlocal interfacial model for 3D short-range wetting at planar and nonplanar walls. The model is characterized by a binding-potential functional depending only on the bulk Ornstein-Zernike correlation function, which arises from different classes of tubelike fluctuations that connect the interface and the substrate. The theory provides a physical explanation for the origin of the effective position-dependent stiffness and binding potential in approximate local theories and also obeys the necessary classical wedge covariance relationship between wetting and wedge filling. Renormalization group and computer simulation studies reveal the strong nonperturbative influence of nonlocality at critical wetting, throwing light on long-standing theoretical problems regarding the order of the phase transition.

Nonlocality and Short-Range Wetting Phenomena

Science.gov (United States)

Parry, A. O.; Romero-Enrique, J. M.; Lazarides, A.

2004-08-01

We propose a nonlocal interfacial model for 3D short-range wetting at planar and nonplanar walls. The model is characterized by a binding-potential functional depending only on the bulk Ornstein-Zernike correlation function, which arises from different classes of tubelike fluctuations that connect the interface and the substrate. The theory provides a physical explanation for the origin of the effective position-dependent stiffness and binding potential in approximate local theories and also obeys the necessary classical wedge covariance relationship between wetting and wedge filling. Renormalization group and computer simulation studies reveal the strong nonperturbative influence of nonlocality at critical wetting, throwing light on long-standing theoretical problems regarding the order of the phase transition.

Short-range clustering and decomposition in copper-nickel and copper-nickel-iron alloys

International Nuclear Information System (INIS)

Aalders, T.J.A.

1982-07-01

The thermodynamic equilibrium state of short-range clustering and the kinetics of short-range clustering and decomposition has been studied for a number of CuNi(Fe)-alloys by means of neutron scattering. The validity of the theories, which are usually applied to describe spinodal decomposition, nucleation and growth, coarsening etc., was investigated. It was shown that for the investigated substances the conventional theory of spinodal decomposition is valid for the relaxation of short-range clustering only for the case that the initial and final states do not differ too much. The dynamical scaling procedure described by Lebowitz et al. did not lead to a time-independent scaled function F(x) for the relaxation of short-range clustering, for the early stages of decomposition and for the case that an alloy, which was already decomposed at the quench temperature T 1 , was annealed at a temperature T 2 (T 1 ). For the later stages of decomposition, however, the scaling procedure was indeed successful. The coarsening of the alloys could, except for the later stages, be described by the Lifshitz-Slyozov theory. (Auth.)

Nuclear chromodynamics: applications of QCD to relativistic multiquark systems

International Nuclear Information System (INIS)

Brodsky, S.J.; Ji, C.R.

1984-07-01

We review the applications of quantum chromodynamics to nuclear multiquark systems. In particular, predictions are given for the deuteron reduced form factor in the high momentum transfer region, hidden color components in nuclear wavefunctions, and the short distance effective force between nucleons. A new antisymmetrization technique is presented which allows a basis for relativistic multiquark wavefunctions and solutions to their evolution to short distances. Areas in which conventional nuclear theory conflicts with QCD are also briefly reviewed. 48 references

Small Device For Short-Range Antenna Measurements Using Optics

DEFF Research Database (Denmark)

Yanakiev, Boyan Radkov; Nielsen, Jesper Ødum; Christensen, Morten

2011-01-01

This paper gives a practical solution for implementing an antenna radiation pattern measurement device using optical fibers. It is suitable for anechoic chambers as well as short range channel sounding. The device is optimized for small size and provides a cheap and easy way to make optical antenna...

Energy-range relations for hadrons in nuclear matter

Science.gov (United States)

Strugalski, Z.

1985-01-01

Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.

UMER: An analog computer for dynamics of swarms interacting via long-range forces

International Nuclear Information System (INIS)

Kishek, R.A.; Bai, G.; Bernal, S.; Feldman, D.; Godlove, T.F.; Haber, I.; O'Shea, P.G.; Quinn, B.; Papadopoulos, C.; Reiser, M.; Stratakis, D.; Tian, K.; Tobin, C.J.; Walter, M.

2006-01-01

Some of the most challenging and interesting problems in nature involve large numbers of objects or particles mutually interacting through long-range forces. Examples range from galaxies and plasmas to flocks of birds and traffic flow on a highway. Even in cases where the form of the interacting force is precisely known, such as the 1/r 2 -dependent Coulomb and gravitational forces, such problems present a formidable theoretical and modeling challenge for large numbers of interacting bodies. This paper reports on a newly constructed, scaled particle accelerator that will serve as an experimental testbed for the dynamics of swarms interacting through long-range forces. Primarily designed for intense beam dynamics studies for advanced accelerators, the University of Maryland Electron Ring (UMER) design is described in detail and an update on commissioning is provided. An example application to a system other than a charged particle beam is discussed

Free cooling of hard-spheres with short and long range interactions

NARCIS (Netherlands)

Gonzalez Briones, Sebastián; Thornton, Anthony Richard; Luding, Stefan

2015-01-01

We study the stability, the clustering and the phase-diagram of free cooling granular gases. The systems consist of mono-disperse particles with additional non-contact (long-range) interactions, and are simulated here by the event-driven molecular dynamics algorithm with discrete (short-range

Russia's Nuclear Forces: Between Disarmament and Modernization

Energy Technology Data Exchange (ETDEWEB)

Podvig, Pavel

2011-04-01

missile defense. They would also have to address the issue of tactical nuclear weapons, which have not been included in arms control efforts so far. Each of these problems presents a serious challenge to Russia and the United States, especially if they maintain the emphasis on traditional Cold War notions of strategic stability and parity. However, as this analysis suggests, recent progress in nuclear disarmament and the willingness of both countries to engage in a dialogue on a range of issues give the two countries an opportunity to reduce the importance of nuclear weapons in their relationship. The paper begins with an overview of the current status of the Russian strategic nuclear forces and the strategic modernization program that is undertaken by Russia. It then considers the role that missile defense and tactical nuclear weapons could play during the next round of nuclear arms control negotiations. (author)

Many-body forces in nuclear shell-model

International Nuclear Information System (INIS)

Rath, P.K.

1985-01-01

In the microscopic derivation of the effective Hamiltonian for the nuclear shell model many-body forces between the valence nucleons occur. These many-body forces can be discriminated in ''real'' many-body forces, which can be related to mesonic and internal degrees of freedom of the nucleons, and ''effective'' many-body forces, which arise by the confinement of the nucleonic Hilbert space to the finite-dimension shell-model space. In the present thesis the influences of such three-body forces on the spectra of sd-shell nuclei are studied. For this the two common techniques for shell-model calculations (Oak Ridge-Rochester and Glasgow representation) are extended in such way that a general three-body term in the Hamiltonian can be regarded. The studies show that the repulsive contributions of the considered three-nucleon forces become more important with increasing number of valence nucleons. By this the particle-number dependence of empirical two-nucleon forces can be qualitatively explained. A special kind of effective many-body force occurs in the folded diagram expansion of the energy-dependent effective Hamiltonian for the shell model. Thereby it is shown that the contributions of the folded diagrams with three nucleons are just as important as those with two nucleons. Thus it is to be suspected that the folded diagram expansion contains many-particle terms with arbitrary particle number. The present studies however show that four nucleon effects are neglegible so that the folded diagram expansion can be confined to two- and three-particle terms. In shell-model calculations which extend over several main shells the influences of the spurious center-of-mass motion must be regarded. A procedure is discussed by which these spurious degrees of freedom can be exactly separated. (orig.) [de

Unsupervised learning in neural networks with short range synapses

Science.gov (United States)

Brunnet, L. G.; Agnes, E. J.; Mizusaki, B. E. P.; Erichsen, R., Jr.

2013-01-01

Different areas of the brain are involved in specific aspects of the information being processed both in learning and in memory formation. For example, the hippocampus is important in the consolidation of information from short-term memory to long-term memory, while emotional memory seems to be dealt by the amygdala. On the microscopic scale the underlying structures in these areas differ in the kind of neurons involved, in their connectivity, or in their clustering degree but, at this level, learning and memory are attributed to neuronal synapses mediated by longterm potentiation and long-term depression. In this work we explore the properties of a short range synaptic connection network, a nearest neighbor lattice composed mostly by excitatory neurons and a fraction of inhibitory ones. The mechanism of synaptic modification responsible for the emergence of memory is Spike-Timing-Dependent Plasticity (STDP), a Hebbian-like rule, where potentiation/depression is acquired when causal/non-causal spikes happen in a synapse involving two neurons. The system is intended to store and recognize memories associated to spatial external inputs presented as simple geometrical forms. The synaptic modifications are continuously applied to excitatory connections, including a homeostasis rule and STDP. In this work we explore the different scenarios under which a network with short range connections can accomplish the task of storing and recognizing simple connected patterns.

Short range order in liquid pnictides

International Nuclear Information System (INIS)

Mayo, M; Makov, G; Yahel, E; Greenberg, Y

2013-01-01

Liquid pnictides have anomalous physical properties and complex radial distribution functions. The quasi-crystalline model of liquid structure is applied to interpret the three-dimensional structure of liquid pnictides. It is shown that all the column V elements can be characterized by a short range order lattice symmetry similar to that of the underlying solid, the A7 structure, which originates from a Peierls distorted simple cubic lattice. The evolution of the liquid structure down the column as well as its temperature and pressure dependence is interpreted by means of the effect of thermodynamic parameters on the Peierls distortion. Surprisingly, it is found that the Peierls effect increases with temperature and the nearest neighbour distances exhibit negative thermal expansion. (paper)

Nuclear forces and high-performance computing: The perfect match

International Nuclear Information System (INIS)

Luu, T; Walker-Loud, A

2009-01-01

High-performance computing is now enabling the calculation of certain hadronic interaction parameters directly from Quantum Chromodynamics, the quantum field theory that governs the behavior of quarks and gluons and is ultimately responsible for the nuclear strong force. In this paper we briefly describe the state of the field and show how other aspects of hadronic interactions will be ascertained in the near future. We give estimates of computational requirements needed to obtain these goals, and outline a procedure for incorporating these results into the broader nuclear physics community.

Report of the Office of Nuclear Reactor Regulation technical assistance task force

International Nuclear Information System (INIS)

1981-11-01

In 1981, the Director of the Office of Nuclear Reactor Regulation (NRR) of the Nuclear Regulatory Commission (NRC) chartered a task force to assess the office program of technical assistance and to recommend improvements. The task force divided the technical assistance program into four areas, and the practices in each area were assessed through a series of surveys of staff, management, and contractor personnel. The task force placed emphasis in its interview and assessment process on the problem areas that exist in the technical assistance program. The report thus reflects a weight on the faults found as a result of the inquiries made. The four major areas of technical assistance contracting studied were program planning, program management and execution, program control and management information systems, and program administration and coordination

Dependence of Coulomb Sum Rule on the Short Range Correlation by Using Av18 Potential

Science.gov (United States)

Modarres, M.; Moeini, H.; Moshfegh, H. R.

The Coulomb sum rule (CSR) and structure factor are calculated for inelastic electron scattering from nuclear matter at zero and finite temperature in the nonrelativistic limit. The effect of short-range correlation (SRC) is presented by using lowest order constrained variational (LOCV) method and the Argonne Av18 and Δ-Reid soft-core potentials. The effects of different potentials as well as temperature are investigated. It is found that the nonrelativistic version of Bjorken scaling approximately sets in at the momentum transfer of about 1.1 to 1.2 GeV/c and the increase of temperature makes it to decrease. While different potentials do not significantly change CSR, the SRC improves the Coulomb sum rule and we get reasonably close results to both experimental data and others theoretical predictions.

New Law on Nuclear Energy into force on March 1, 1988

International Nuclear Information System (INIS)

Santaholma, J.

1988-01-01

In Finland new Law on Nuclear Energy enters into force on March 1, 1988 after ten years' preparation work. The Parliament approved the new law, compensating the old law on atomic energy on 1957, unanimously in November 1987. The new law provides the decisions on new nuclear power plants to be made by the Government and finally ratified by the Parliament

Economic burden of a nuclear force: no data in search of a theory

International Nuclear Information System (INIS)

Rochlin, G.I.

1983-01-01

A country which decides to develop a militarily significant nuclear force after conducting an acknowledged test of a nuclear explosive device must progress up a series of costs. This chapter examines cases in which the economic costs of moving from one force level to the next are sufficient to limit the rate of growth of capability. It finds that when economic barriers are severe, there seems to be some economic strategies for managing in terms of limiting force improvement through the manipulation of economic factors. These economic levers sometimes go against the grain of traditional politico-military approaches. In all cases, it is necessary to consider whether the overall and long-term effects of the levers applied to a specific country strengthen or weaken the overall strategy, which is to limit and restrain the proliferation of nuclear weapons in general and not just in specific cases. 16 references, 5 figures, 3 tables

A short model excitation of an asymmetric force free superconducting transmission line magnet

Energy Technology Data Exchange (ETDEWEB)

Wake, M.; Sato, H.; /KEK, Tsukuba; Carcagno, R.; Foster, W.; Hays, S.; Kashikhin, V.; Oleck, A.; Piekarz, H.; Rabehl, R,; /Fermilab

2005-09-01

A short model of asymmetric force free magnet with single beam aperture was tested at Fermilab together with the excitation test of VLHC transmission line magnet. The design concept of asymmetric force free superconducting magnet was verified by the test. The testing reached up to 104 kA current and no indication of force imbalance was observed. Since the model magnet length was only 10cm, A 0.75m model was constructed and tested at KEK with low current to ensure the validity of the design. The cool down and the excitation at KEK were also successful finding very small thermal contraction of the conductor and reasonable field homogeneity.

Yukawa Tomonaga and nuclear physics

International Nuclear Information System (INIS)

Udagawa, Takeshi

2006-01-01

Yukawa and Tomonaga made epoch-making contributions to the development of elementary particle physics; Yukawa proposed the meson theory of the nuclear force and Tomonaga developed renormalization theory in QED. The nuclear force is, of course, the basis of all nuclear physics. In this sense, Yukawa's work set the foundations for nuclear physics. Tomonaga worked in his late years on problems of collective motion appearing in many many-particle-systems, nuclear systems being one of the examples. Yukawa and Tomonaga were also deeply involved in founding the Institute of Fundamental Physics and Institute for Nuclear Study, through which they made invaluable contributions to the development of the field of nuclear physics. It is almost impossible to report in this short article on all of what they have achieved and thus I would like to discuss here their contributions to nuclear physics only in a limited scope, based on my personal reminiscence of them. (author)

Increasing Uncertainty: The Dangers of Relying on Conventional Forces for Nuclear Deterrence

Science.gov (United States)

2016-03-14

72 | Air & Space Power Journal Increasing Uncertainty The Dangers of Relying on Conventional Forces for Nuclear Deterrence Jennifer Bradley To put...relationships and should serve as the cornerstone of US nuclear deterrence policy. Although Russia and China are not identified as adversaries of...exactly what has happened over the past year. The US decision to meet the needs of deterrence by relying less on nuclear weapons and instead devel- oping

Two citizen task forces and the challenge of the evolving nuclear waste siting process

International Nuclear Information System (INIS)

Peelle, E.B.

1990-01-01

Siting any nuclear waste facility is problematic in today's climate of distrust toward nuclear agencies and fear of nuclear waste. This study compares and contrasts the siting and public participation processes as two citizen task forces dealt with their difficult responsibilities. 10 refs., 3 tabs

On the universality of the long-/short-range separation in multiconfigurational density-functional theory

Science.gov (United States)

Fromager, Emmanuel; Toulouse, Julien; Jensen, Hans Jørgen Aa.

2007-02-01

In many cases, the dynamic correlation can be calculated quite accurately and at a fairly low computational cost in Kohn-Sham density-functional theory (KS-DFT), using current standard approximate functionals. However, in general, KS-DFT does not treat static correlation effects (near degeneracy) adequately which, on the other hand, can be described in wave-function theory (WFT), for example, with a multiconfigurational self-consistent field (MCSCF) model. It is therefore of high interest to develop a hybrid model which combines the best of both WFT and DFT approaches. The merge of WFT and DFT can be achieved by splitting the two-electron interaction into long-range and short-range parts. The long-range part is then treated by WFT and the short-range part by DFT. In this work the authors consider the so-called "erf" long-range interaction erf(μr12)/r12, which is based on the standard error function, and where μ is a free parameter which controls the range of the long-/short-range decomposition. In order to formulate a general method, they propose a recipe for the definition of an optimal μopt parameter, which is independent of the approximate short-range functional and the approximate wave function, and they discuss its universality. Calculations on a test set consisting of He, Be, Ne, Mg, H2, N2, and H2O yield μopt≈0.4a.u.. A similar analysis on other types of test systems such as actinide compounds is currently in progress. Using the value of 0.4a.u. for μ, encouraging results are obtained with the hybrid MCSCF-DFT method for the dissociation energies of H2, N2, and H2O, with both short-range local-density approximation and PBE-type functionals.

Entry into force of the Convention on Supplementary Compensation for Nuclear Damage: Opening the umbrella

International Nuclear Information System (INIS)

McRae, Ben

2015-01-01

There are 431 commercial nuclear power plants around the world. On 14 April 2015, 193 of these power plants were covered by a nuclear liability instrument (118 power plants by the Paris Convention and 75 by the Vienna Convention). With the entry into force of the Convention on Supplementary Compensation for Nuclear Damage (CSC)4 on 15 April 2015, the number of power plants covered by a nuclear liability instrument increased to 340. Thus, the entry into force of the CSC marked a major milestone towards the establishment of a global nuclear liability regime. This article discusses several events that have promoted progress towards a global nuclear liability regime and then addresses several questions that may arise as countries consider actions necessary to achieve such a regime. (author)

The Frontiers of Nuclear Science: A Long-Range Plan

Energy Technology Data Exchange (ETDEWEB)

None, None

2007-12-01

In a letter dated July 17, 2006, the Department of Energy’s (DOE) Office of Science for Nuclear Physics and the National Science Foundation’s (NSF) Mathematical and Physical Sciences Directorate charged the Nuclear Science Advisory Committee (NSAC) to “conduct a study of the opportunities and priorities for U.S. nuclear physics research and recommend a long range plan that will provide a framework for coordinated advancement of the nation’s nuclear science research programs over the next decade.” This request set in motion a bottom-up review and forward look by the nuclear science community. With input from this community-wide process, a 59 member working group, which included the present NSAC members, gathered at the beginning of May, 2007, to develop guidance on how to optimize the future research directions for the field based on the projected resources outlined in the charge letter from DOE and NSF. A new long range plan—The Frontiers of Nuclear Science—grew out of this meeting. For the last decade, the top priority for nuclear science has been to utilize the flagship facilities that were built with investments by the nation in the 1980s and 1990s. Research with these facilities has led to many significant new discoveries that have changed our understanding of the world in which we live. But new discoveries demand new facilities, and the successes cannot continue indefinitely without new investment.

Consultation and cooperation in NATO: nuclear planning, 1975-1987

Energy Technology Data Exchange (ETDEWEB)

Chernoff, F.B.

1987-01-01

This study looks at three types of explanation of international cooperation, which deal in different ways with communication and consultation. Themost-general theoretical explanation contrasts recent realist theories, like those of Waltz and Gilpin, with Keohane's functional theory of regimes. Secondly, the study looks at theories of information flow and processing (an element of consultation) within the alliance, like those of Deutsch and Steinbruner. Such theories explain governmental behavior using concepts like equilibrium of systems and feedback loop. Third, the study considers hypotheses that deal specifically with NATO and military alliances. The hypotheses relate alliance consultation processes to the cooperativeness of the cases' outcomes. Evidence is drawn from case studies of NATO decision-making. The cases include politically sensitive deployment issues, like the enhanced radiation warhead controversy in 1977-78 and the intermediate-range nuclear force deployment decision in 1979, and important, but less politically volatile arms-control decisions, including the 1975 option three proposal, the French plan for a conference on disarmament in Europe, approved in 1980, and the 1987 American zero-zero proposal on short- and intermediate-range nuclear forces in Europe.

Condensins Exert Force on Chromatin-Nuclear Envelope Tethers to Mediate Nucleoplasmic Reticulum Formation in Drosophila melanogaster

Science.gov (United States)

Bozler, Julianna; Nguyen, Huy Q.; Rogers, Gregory C.; Bosco, Giovanni

2014-01-01

Although the nuclear envelope is known primarily for its role as a boundary between the nucleus and cytoplasm in eukaryotes, it plays a vital and dynamic role in many cellular processes. Studies of nuclear structure have revealed tissue-specific changes in nuclear envelope architecture, suggesting that its three-dimensional structure contributes to its functionality. Despite the importance of the nuclear envelope, the factors that regulate and maintain nuclear envelope shape remain largely unexplored. The nuclear envelope makes extensive and dynamic interactions with the underlying chromatin. Given this inexorable link between chromatin and the nuclear envelope, it is possible that local and global chromatin organization reciprocally impact nuclear envelope form and function. In this study, we use Drosophila salivary glands to show that the three-dimensional structure of the nuclear envelope can be altered with condensin II-mediated chromatin condensation. Both naturally occurring and engineered chromatin-envelope interactions are sufficient to allow chromatin compaction forces to drive distortions of the nuclear envelope. Weakening of the nuclear lamina further enhanced envelope remodeling, suggesting that envelope structure is capable of counterbalancing chromatin compaction forces. Our experiments reveal that the nucleoplasmic reticulum is born of the nuclear envelope and remains dynamic in that they can be reabsorbed into the nuclear envelope. We propose a model where inner nuclear envelope-chromatin tethers allow interphase chromosome movements to change nuclear envelope morphology. Therefore, interphase chromatin compaction may be a normal mechanism that reorganizes nuclear architecture, while under pathological conditions, such as laminopathies, compaction forces may contribute to defects in nuclear morphology. PMID:25552604

Condensins exert force on chromatin-nuclear envelope tethers to mediate nucleoplasmic reticulum formation in Drosophila melanogaster.

Science.gov (United States)

Bozler, Julianna; Nguyen, Huy Q; Rogers, Gregory C; Bosco, Giovanni

2014-12-30

Although the nuclear envelope is known primarily for its role as a boundary between the nucleus and cytoplasm in eukaryotes, it plays a vital and dynamic role in many cellular processes. Studies of nuclear structure have revealed tissue-specific changes in nuclear envelope architecture, suggesting that its three-dimensional structure contributes to its functionality. Despite the importance of the nuclear envelope, the factors that regulate and maintain nuclear envelope shape remain largely unexplored. The nuclear envelope makes extensive and dynamic interactions with the underlying chromatin. Given this inexorable link between chromatin and the nuclear envelope, it is possible that local and global chromatin organization reciprocally impact nuclear envelope form and function. In this study, we use Drosophila salivary glands to show that the three-dimensional structure of the nuclear envelope can be altered with condensin II-mediated chromatin condensation. Both naturally occurring and engineered chromatin-envelope interactions are sufficient to allow chromatin compaction forces to drive distortions of the nuclear envelope. Weakening of the nuclear lamina further enhanced envelope remodeling, suggesting that envelope structure is capable of counterbalancing chromatin compaction forces. Our experiments reveal that the nucleoplasmic reticulum is born of the nuclear envelope and remains dynamic in that they can be reabsorbed into the nuclear envelope. We propose a model where inner nuclear envelope-chromatin tethers allow interphase chromosome movements to change nuclear envelope morphology. Therefore, interphase chromatin compaction may be a normal mechanism that reorganizes nuclear architecture, while under pathological conditions, such as laminopathies, compaction forces may contribute to defects in nuclear morphology. Copyright © 2015 Bozler et al.

Short-time dynamics of lysozyme solutions with competing short-range attraction and long-range repulsion: Experiment and theory

Science.gov (United States)

Riest, Jonas; Nägele, Gerhard; Liu, Yun; Wagner, Norman J.; Godfrin, P. Douglas

2018-02-01

Recently, atypical static features of microstructural ordering in low-salinity lysozyme protein solutions have been extensively explored experimentally and explained theoretically based on a short-range attractive plus long-range repulsive (SALR) interaction potential. However, the protein dynamics and the relationship to the atypical SALR structure remain to be demonstrated. Here, the applicability of semi-analytic theoretical methods predicting diffusion properties and viscosity in isotropic particle suspensions to low-salinity lysozyme protein solutions is tested. Using the interaction potential parameters previously obtained from static structure factor measurements, our results of Monte Carlo simulations representing seven experimental lysoyzme samples indicate that they exist either in dispersed fluid or random percolated states. The self-consistent Zerah-Hansen scheme is used to describe the static structure factor, S(q), which is the input to our calculation schemes for the short-time hydrodynamic function, H(q), and the zero-frequency viscosity η. The schemes account for hydrodynamic interactions included on an approximate level. Theoretical predictions for H(q) as a function of the wavenumber q quantitatively agree with experimental results at small protein concentrations obtained using neutron spin echo measurements. At higher concentrations, qualitative agreement is preserved although the calculated hydrodynamic functions are overestimated. We attribute the differences for higher concentrations and lower temperatures to translational-rotational diffusion coupling induced by the shape and interaction anisotropy of particles and clusters, patchiness of the lysozyme particle surfaces, and the intra-cluster dynamics, features not included in our simple globular particle model. The theoretical results for the solution viscosity, η, are in qualitative agreement with our experimental data even at higher concentrations. We demonstrate that semi

French Nuclear Forces in the 1980s and 1990s

Science.gov (United States)

1983-08-01

the mid-1990s, the new force structure will be theoretically capable of inflicting massive destruc- tion against the Soviet Union as well as...capacity which turns national territory into a sanctuary. The current French nuclear force structure is shown in table 1 below. -2- TABLE 1 FRENCH...out in favor of the M-2 in 1974 which by 1977 had itself been supplanted by the M-20. The first Sous-marin Nucleaire Lanceur d’Engins I (SNLE) or

Searches for possible T-odd and P-odd short range interactions using polarized nuclei

Directory of Open Access Journals (Sweden)

Chu P. H.

2014-03-01

Full Text Available Various theories predict the possible existence of T-odd and P-odd shortrange forces between spin ½ fermions, proportional to S・r where S is the fermion spin and r is the separation between particles. We use ensembles of polarized nuclei and an un-polarized mass to search for such a force over sub-mm ranges. We established an improved upper bound on the product gsgpn of the scalar coupling to particles in the un-polarized mass and the pseudo-scalar coupling of polarized neutrons for force ranges from 10−4 to 10−2 m, corresponding to a mass range of 2・10−3 to 2・10−5 eV for the exchange boson [1].

Force-induced unzipping of DNA with long-range correlated sequence

OpenAIRE

Allahverdyan, A. E.; Gevorkian, Zh. S.

2002-01-01

We consider force-induced unzipping transition for a heterogeneous DNA model with a long-range correlated base-sequence. It is shown that as compared to the uncorrelated situation, long-range correlations smear the unzipping phase-transition, change its universality class and lead to non-self-averaging: the averaged behavior strongly differs from the typical ones. Several basic scenarios for this typical behavior are revealed and explained. The results can be relevant for explaining the biolo...

Preventing nuclear terrorism: the report and papers of the International Task Force on Prevention of Nuclear Terrorism

International Nuclear Information System (INIS)

Leventhal, P.; Alexander, Y.

1987-01-01

The International Task Force on Prevention of Nuclear Terrorism, formed in 1985 under the Nuclear Control Institute, commissioned 26 studies and produced an extensive report on the problem and prevention of nuclear terrorism, Part I of this book is the full report, and part II contains the individual studies under two section: (A) Defining the Threat (8 studies); and (B) Strategies for Dealing with the Threat (18 studies). Detailed recommendations are made, in many of the studies, for better protection of nuclear weapons, materials, and facilities; greater cooperation among national intelligence agencies; tighter controls on nuclear transfers; more effective arms control initiatives; and emergency management programs. A separate abstract was prepared for the report and each of the 26 studies

Short-range contacts govern the performance of industry-relevant battery cathodes

Science.gov (United States)

Morelly, Samantha L.; Alvarez, Nicolas J.; Tang, Maureen H.

2018-05-01

Fundamental understanding of how processing affects composite battery electrode structure and performance is still lacking, especially for industry-relevant electrodes with low fractions of inactive material. This work combines rheology, electronic conductivity measurements, and battery rate capability tests to prove that short-range electronic contacts are more important to cathode rate capability than either ion transport or long-range electronic conductivity. LiNi0.33Mn0.33Co0.33O2, carbon black, and polyvinylidene difluoride in 1-methyl-2-pyrrolidinone represent a typical commercial electrode with films. Improvements in battery rate capability at constant electrode porosity do not correlate to electronic conductivity, but rather show an optimum fraction of free carbon. Simple comparison of rate capability in electrodes with increased total carbon loading (3 wt%) shows improvement for all fractions of free carbon. These results clearly indicate that ion transport cannot be limiting and highlight the critical importance of short-range electronic contacts for controlling battery performance.

Nuclear structure 1985

International Nuclear Information System (INIS)

Broglia, R.; Hagemann, G.; Herskind, B.

1985-01-01

These proceedings of the Niels Bohr Centennial Conference contains 40 lectures in nuclear physics ranging over the following subjects: single particle motion; collective motion at low excitation energy; collective motion at high angular momentum; giant resonances and nuclear forces. (G.J.P.)

Gamma spectrometric characterization of short cooling time nuclear spent fuels using hemispheric CdZnTe detectors

CERN Document Server

Lebrun, A; Szabó, J L; Arenas-Carrasco, J; Arlt, R; Dubreuil, A; Esmailpur-Kazerouni, K

2000-01-01

After years of cooling, nuclear spent fuel gamma emissions are mainly due to caesium isotopes which are emitters at 605, 662 and 796-801 keV. Extensive work has been done on such fuels using various CdTe or CdZnTe probes. When fuels have to be measured after short cooling time (during NPP outage) the spectrum is much more complex due to the important contributions of niobium and zirconium in the 700 keV range. For the first time in a nuclear power plant, four spent fuels of the Kozloduy VVER reactor no 4 were measured during outage, 37 days after shutdown of the reactor. In such conditions, good resolution is of particular interest, so a 20 mm sup 3 hemispheric crystal was used with a resolution better than 7 keV at 662 keV. This paper presents the experimental device and analyzes the results which show that CdZnTe commercially available detectors enabled us to perform a semi-quantitative determination of the burn-up after a short cooling time. In addition, it is discussed how a burn-up evolution code (CESAR)...

Adult mouse motor units develop almost all of their force in the subprimary range: a new all-or-none strategy for force recruitment?

Science.gov (United States)

Manuel, Marin; Heckman, C J

2011-10-19

Classical studies of the mammalian neuromuscular system have shown an impressive adaptation match between the intrinsic properties of motoneurons and the contractile properties of their motor units. In these studies, the rate at which motoneurons start to fire repetitively corresponds to the rate at which individual twitches start to sum, and the firing rate increases linearly with the amount of excitation ("primary range") up to the point where the motor unit develops its maximal force. This allows for the gradation of the force produced by a motor unit by rate modulation. In adult mouse motoneurons, however, we recently described a regime of firing ("subprimary range") that appears at lower excitation than what is required for the primary range, a finding that might challenge the classical conception. To investigate the force production of mouse motor units, we simultaneously recorded, for the first time, the motoneuron discharge elicited by intracellular ramps of current and the force developed by its motor unit. We showed that the motor unit developed nearly its maximal force during the subprimary range. This was found to be the case regardless of the input resistance of the motoneuron, the contraction speed, or the tetanic force of the motor unit. Our work suggests that force modulation in small mammals mainly relies on the number of motor units that are recruited rather than on rate modulation of individual motor units.

Radioactivity a very short introduction

CERN Document Server

Tuniz, Claudio

2012-01-01

Radioactivity: A Very Short Introduction explains radioactivity and discusses its fundamental role in nature. Radioactivity remains misunderstood and feared perhaps because nuclear radiation cannot be detected by human senses, and can undoubtedly do great harm if appropriate precautions are not taken. Radioactivity in the stars and in the Earth and its wide range of applications in biomedicine, science, industry, agriculture are described, as well as the mechanisms of nuclear fission and fusion, and the harnessing of nuclear power. The issues surrounding safety and security and the increasing concerns about nuclear terrorism are also considered.

The Trilateral Force: The Atlantic Alliance and the Future of Nuclear Weapons Strategy

Science.gov (United States)

2013-12-03

Commission Report: Modernizing US. Nuclear Strategy, Force Structure and Posture, Global Zero (2012), 6. 27 Dana Johnson, et al., "Triad, Dyad, Monad...2012. Forsyth, J., B. Saltzman , and G. Schaub. "Remembrance of Things Past: The Enduring Value ofNuclear Weapons." Strategic Studies Quarterly

Evidence for short range corelations from high Q{sup 2} (e,e{prime}) reactions

Energy Technology Data Exchange (ETDEWEB)

Strikman, M.I. [Pennsylvania State Univ., University Park, PA (United States); Frankfurt, L.L.; Sargayan, M.M. [Tel Aviv Univ. (Iceland)] [and others

1994-04-01

For many years now short-range correlations (SRC) in nuclei have been considered as an essential feature of the nuclear wave function. At high energy (e,e{prime}) reactions, where Q{sup 2} > 1 (GeV/c){sup 2}, x = Q{sup 2}/2mq{sub o} > 1 and 1 GeV > q{sub o}> 300 {approximately} 400 MeV the scattering from low momentum nucleons is kinematically suppressed and there the evidence of SRC expected to be more prominent. These reactions have been intensively investigated during the last decade or so at SLAC on both light and heavy nuclei. The above kinematics allows one to compute the cross section through the processes local in space. To explain this the authors analyse the representation of the cross section as a Fourier transform of the commutator of electromagnetic currents and see that the major contribution in the cross section is given by the region of integration.

Probing short-range correlations in asymmetric nuclei with quasi-free pair knockout reactions

Science.gov (United States)

Stevens, Sam; Ryckebusch, Jan; Cosyn, Wim; Waets, Andreas

2018-02-01

Short-range correlations (SRC) in asymmetric nuclei with an unusual neutron-to-proton ratio can be studied with quasi-free two-nucleon knockout processes following the collision between accelerated ions and a proton target. We derive an approximate factorized cross section for those SRC-driven p (A ,p‧N1N2) reactions. Our reaction model hinges on the factorization properties of SRC-driven A (e ,e‧N1N2) reactions for which strong indications are found in theory-experiment comparisons. In order to put our model to the test we compare its predictions with results of 12C (p ,p‧ pn) measurements conducted at Brookhaven National Laboratory (BNL) and find a fair agreement. The model can also reproduce characteristic features of SRC-driven two-nucleon knockout reactions, like back-to-back emission of the correlated nucleons. We study the asymmetry dependence of nuclear SRC by providing predictions for the ratio of proton-proton to proton-neutron knockout cross sections for the carbon isotopes 9-15C thereby covering neutron excess values (N - Z) / Z between -0.5 and +0.5.

Aircraft impact on nuclear power plants concrete structures

International Nuclear Information System (INIS)

Coombs, R.F.; Barbosa, L.C.B.; Santos, S.H.C.

1980-01-01

A summary about the procedures for the analysis of aircraft on concrete structures, aiming to emphasize the aspects related to the nuclear power plants safety, is presented. The impact force is determined by the Riera model. The effect of this impact force on the concrete structures is presented, showing the advantages to use nonlinear behaviour in the concrete submitted to short loads. The simplifications used are shown through a verification example of the nuclear reactor concrete shielding. (E.G.) [pt

Toward Structure Prediction for Short Peptides Using the Improved SAAP Force Field Parameters

Directory of Open Access Journals (Sweden)

Kenichi Dedachi

2013-01-01

Full Text Available Based on the observation that Ramachandran-type potential energy surfaces of single amino acid units in water are in good agreement with statistical structures of the corresponding amino acid residues in proteins, we recently developed a new all-atom force field called SAAP, in which the total energy function for a polypeptide is expressed basically as a sum of single amino acid potentials and electrostatic and Lennard-Jones potentials between the amino acid units. In this study, the SAAP force field (SAAPFF parameters were improved, and classical canonical Monte Carlo (MC simulation was carried out for short peptide models, that is, Met-enkephalin and chignolin, at 300 K in an implicit water model. Diverse structures were reasonably obtained for Met-enkephalin, while three folded structures, one of which corresponds to a native-like structure with three native hydrogen bonds, were obtained for chignolin. The results suggested that the SAAP-MC method is useful for conformational sampling for the short peptides. A protocol of SAAP-MC simulation followed by structural clustering and examination of the obtained structures by ab initio calculation or simply by the number of the hydrogen bonds (or the hardness was demonstrated to be an effective strategy toward structure prediction for short peptide molecules.

Short-range disorder in pseudobinary ionic alloys

International Nuclear Information System (INIS)

Di Cicco, Andrea; Principi, Emiliano; Filipponi, Adriano

2002-01-01

The short-range distribution functions of the RbBr 1-x I x solid and molten ionic alloys have been accurately measured using multiple-edge refinement of the K-edge extended x-ray absorption fine structure spectra (EXAFS). The local structure is characterized by two well-defined first-neighbor peaks associated with the Rb-I and Rb-Br distributions, both for solid and liquid alloys. The distribution of distances in solid alloys gives experimental evidence to available theoretical models. In the liquid, the two distance distributions are found to be practically independent of the concentration x. The effect of different effective charge screening of the ions is observed in the molten systems for limiting concentrations

Role of long- and short-range hydrophobic, hydrophilic and charged residues contact network in protein’s structural organization

Directory of Open Access Journals (Sweden)

Sengupta Dhriti

2012-06-01

higher interaction strength between amino acids, give extra stability to the tertiary structure of the thermophiles. All the subnetworks at different length scales (ARNs, LRNs and SRNs show assortativity mixing property of their participating amino acids. While there exists a significant higher percentage of hydrophobic subclusters over others in ARNs and LRNs; we do not find the assortative mixing behaviour of any the subclusters in SRNs. The clustering coefficient of hydrophobic subclusters in long-range network is the highest among types of subnetworks. There exist highly cliquish hydrophobic nodes followed by charged nodes in LRNs and ARNs; on the other hand, we observe the highest dominance of charged residues cliques in short-range networks. Studies on the perimeter of the cliques also show higher occurrences of hydrophobic and charged residues’ cliques. Conclusions The simple framework of protein contact networks and their subnetworks based on London van der Waals force is able to capture several known properties of protein structure as well as can unravel several new features. The thermophiles do not only have the higher number of long-range interactions; they also have larger cluster of connected residues at higher interaction strengths among amino acids, than their mesophilic counterparts. It can reestablish the significant role of long-range hydrophobic clusters in protein folding and stabilization; at the same time, it shed light on the higher communication ability of hydrophobic subnetworks over the others. The results give an indication of the controlling role of hydrophobic subclusters in determining protein’s folding rate. The occurrences of higher perimeters of hydrophobic and charged cliques imply the role of charged residues as well as hydrophobic residues in stabilizing the distant part of primary structure of a protein through London van der Waals interaction.

India’s Evolving Nuclear Force and Its Implications for U.S. Strategy in the Asia-Pacific

Science.gov (United States)

2016-06-01

development and the norms of restraint in the present nuclear doctrine. Conclusion. The growing diversity of India’s delivery vehicles generates questions...India has reportedly rejected such proposals due to reasoning that its nuclear force must also be built to deter China and cannot be capped sole- ly...security policy formulation. iii v Strategic Studies Institute and U.S. Army War College Press INDIA’S EVOLVING NUCLEAR FORCE AND ITS IMPLICATIONS FOR

Chemical and topological short-range order in metallic glasses

International Nuclear Information System (INIS)

Vincze, I.; Schaafsma, A.S.; Van der Woude, F.; Kemeny, T.; Lovas, A.

1980-10-01

Moessbauer spectroscopy is applied to the study of chemical short-range order in (Fe,Ni)B metallic glasses. It is found that the atomic arrangement in melt-quenched glasses closely resembles that of the crystalline counterparts (Fe 3 B is tetragonal, Ni 3 B is orthorombic). The distribution of transition metal atoms is not random at high Ni concentrations: Ni atoms prefer a neighbourhood with a higher boron coordination. (P.L.)

Air Force Nuclear Enterprise Organization: A Case Study

Science.gov (United States)

2016-09-15

changes. To address the objectives of this study, five investigative questions ( IQ ) are posed: IQ1. What constitutes the Air Force Nuclear Enterprise...are an effective tool being used to raise the level of training. But it is not only necessary to move away from training that merely checks a box...down to an authoritative brain trust of just a few pertinent players (e.g. AFGSC/CC, HAF/A10 Director, AFNWC/CC, etc). As this study has portrayed

Electronically driven short-range lattice instability: Cluster effects in superconductors

International Nuclear Information System (INIS)

Szasz, A.

1991-01-01

In the first part of this series, short- and medium-range interactions in superconductors were investigated. In this paper a discussion is made on the cluster-mass dependence of the superconductive transition temperature and the relevant phenomenon of electron localization. A comparison with experiments is given; the predictions fit well to the observations

Comparative study for endenergy supply with nuclear district heating and with nuclear long distance energy

International Nuclear Information System (INIS)

Dietrich, G.

1975-07-01

The future energy supply of the Federal Republic of Germany will be orientated to secure energy carriers. Moreover economical energy consumption and environmental protection will be a force for an increased application of district heating and nuclear long distance energy. The technics of generation, transport and distribution of the two energy carriers will be discussed, besides a short review of application areas and potentials. The cost comparisons by models show that there are special advantages for both systems. Nevertheless the conclusions from the study can be to favour nuclear long distance energy because of its wide application range in the whole heat market. But there is also the competition with combined heat and power generation on fossil basis, as practised in many industrial companies. As a result of a regional analysis of the area Aachen-Moenchengladbach-Koeln, the cost advantages of the nuclear long distance energy as a parameter of current prices are confirmed. Nuclear long distance energy, in combination with the high temperature reactor and a developed technic of catalysts up to temperatures of 900 K, is an energy source which will be independant of regional necessities, secure, non pollutant and economic. (orig.) [de

WIX: statistical nuclear multifragmentation with collective expansion and Coulomb forces

Science.gov (United States)

Randrup, J.∅rgen

1993-10-01

By suitable augmentation of the event generator FREESCO, a code WIX has been constructed with which it is possible to simulate the statistical multifragmentation of a specified nuclear source, which may be both hollow and deformed, in the presence of a collective expansion and with the interfragment Coulomb forces included.

Economic efficency and competitive position of nuclear energy today

International Nuclear Information System (INIS)

Schmitt, D.

1988-01-01

In spite of the relaxation making itself felt at the moment on the world energy markets, the competitive position of nuclear power from either existing or shortly to be connected power plants remains safe. Any attempt at doing without this extraordinarily convenient vehicle of power generation would mean to severely force up costs and expenses. The competitive position of existing nuclear power plants is assumed to remain untouched through the coming decade. In spite of the presently very low world market prices imported coal is especially affected by, even abstract economic analyses show nuclear energy to come out superior to all other alternatives providing for the electric power supply of the Federal Republic of Germany. Once the over-capacity is reduced and under control, a longer-term superior competitive position of nuclear power, however, presupposes a rise in prices full level with those of the neighbor countries. At any rate and for the time being, the divergence of electric power from imported coal prices which was even obvious in the mean load range has diminished. The superior position of nuclear power in the base load range can be maintained through avoiding further rises in operating costs by gradual rationalization and standardization. (orig./HP) [de

Long-term reliability evaluation of nuclear containments with tendon force degradation

International Nuclear Information System (INIS)

Kim, Sang-Hyo; Choi, Moon-Seock; Joung, Jung-Yeun; Kim, Kun-Soo

2013-01-01

Highlights: • A probabilistic model on long-term degradation of tendon force is developed. • By using the model, we performed reliability evaluation of nuclear containment. • The analysis is also performed for the case with the strict maintenance programme. • We showed how to satisfy the target safety in the containments facing life extension. - Abstract: The long-term reliability of nuclear containment is important for operating nuclear power plants. In particular, long-term reliability should be clarified when the service life of nuclear containment is being extended. This study focuses not only on determining the reliability of nuclear containment but also presenting the reliability improvement by strengthening the containment itself or by running a strict maintenance programme. The degradation characteristics of tendon force are estimated from the data recorded during in-service inspection of containments. A reliability analysis is conducted for a limit state of through-wall cracking, which is conservative, but most crucial limit state. The results of this analysis indicate that reliability is the lowest at 3/4 height of the containment wall. Therefore, this location is the most vulnerable for the specific limit state considered in this analysis. Furthermore, changes in structural reliability owing to an increase in the number of inspecting tendons are analysed for verifying the effect of the maintenance program's intensity on expected containment reliability. In the last part of this study, an example of obtaining target reliability of nuclear containment by strengthening its structural resistance is presented. A case study is conducted for exemplifying the effect of strengthening work on containment reliability, especially during extended service life

Temperature dependence of single-particle properties in nuclear matter

International Nuclear Information System (INIS)

Zuo, W.; Lu, G.C.; Li, Z.H.; Lombardo, U.; Schulze, H.-J.

2006-01-01

The single-nucleon potential in hot nuclear matter is investigated in the framework of the Brueckner theory by adopting the realistic Argonne V 18 or Nijmegen 93 two-body nucleon-nucleon interaction supplemented by a microscopic three-body force. The rearrangement contribution to the single-particle potential induced by the ground state correlations is calculated in terms of the hole-line expansion of the mass operator and provides a significant repulsive contribution in the low-momentum region around and below the Fermi surface. Increasing temperature leads to a reduction of the effect, while increasing density makes it become stronger. The three-body force suppresses somewhat the ground state correlations due to its strong short-range repulsion, increasing with density. Inclusion of the three-body force contribution results in a quite different temperature dependence of the single-particle potential at high enough densities as compared to that adopting the pure two-body force. The effects of three-body force and ground state correlations on the nucleon effective mass are also discussed

Long-range force and moment calculations in multiresolution simulations of molecular systems

International Nuclear Information System (INIS)

Poursina, Mohammad; Anderson, Kurt S.

2012-01-01

Multiresolution simulations of molecular systems such as DNAs, RNAs, and proteins are implemented using models with different resolutions ranging from a fully atomistic model to coarse-grained molecules, or even to continuum level system descriptions. For such simulations, pairwise force calculation is a serious bottleneck which can impose a prohibitive amount of computational load on the simulation if not performed wisely. Herein, we approximate the resultant force due to long-range particle-body and body-body interactions applicable to multiresolution simulations. Since the resultant force does not necessarily act through the center of mass of the body, it creates a moment about the mass center. Although this potentially important torque is neglected in many coarse-grained models which only use particle dynamics to formulate the dynamics of the system, it should be calculated and used when coarse-grained simulations are performed in a multibody scheme. Herein, the approximation for this moment due to far-field particle-body and body-body interactions is also provided.

Direct-Bandgap InAs Quantum-Dots Have Long-Range Electron--Hole Exchange Whereas Indirect Gap Si Dots Have Short-Range Exchange

International Nuclear Information System (INIS)

Juo, J.W.; Franceschetti, A.; Zunger, A.

2009-01-01

Excitons in quantum dots manifest a lower-energy spin-forbidden 'dark' state below a spin-allowed 'bright' state; this splitting originates from electron-hole (e-h) exchange interactions, which are strongly enhanced by quantum confinement. The e-h exchange interaction may have both a short-range and a long-range component. Calculating numerically the e-h exchange energies from atomistic pseudopotential wave functions, we show here that in direct-gap quantum dots (such as InAs) the e-h exchange interaction is dominated by the long-range component, whereas in indirect-gap quantum dots (such as Si) only the short-range component survives. As a result, the exciton dark/bright splitting scales as 1/R 2 in InAs dots and 1/R 3 in Si dots, where R is the quantum-dot radius.

Van der Waals Forces and Photon-Less Effective Field Theory

International Nuclear Information System (INIS)

Arriola, E.R.

2011-01-01

In the ultra-cold regime Van der Waals forces between neutral atoms can be represented by short range effective interactions. We show that universal low energy scaling features of the underlying vdW long range force stemming from two photon exchange impose restrictions on an Effective Field Theory without explicit photons. The role of naively redundant operators, relevant to the definition of three body forces, is also analyzed. (author)

The long and short run forcing variables of purchasing power parity of ASEAN-5

OpenAIRE

Abdalrahman AbuDalu; Elsadig Musa Ahmed

2013-01-01

This study examines the long-run and short-run forcing variables of purchasing power parity (PPP) for ASEAN-5 currencies vis-a-vis the U.S. dollar, i.e., their real effective exchange rate (REER). This study uses the autoregressive distributed lag (ARDL) approach to co-integration over the period 1991:Q1 – 2006:Q2. Our empirical results suggest that the domestic money supply (M1) is a significant long run forcing variable for the REERs of Malaysia, Indonesia, the Philippines, and Singapore. H...

French regulations for countering external violent forces affecting nuclear power stations

International Nuclear Information System (INIS)

Dupraz, B.

1986-01-01

This article describes the general principles underlying nuclear safety regulations to counter external violent forces to which plants can be exposed. It then examines the statutory directives concerning external violences connected with human activities or originating from natural phenomena. 3 refs [fr

Hadronization of quark-diquark model for nucleon structure and nuclear force by path integral

International Nuclear Information System (INIS)

Nagata, Keitaro

2003-01-01

One of the central issues of the hadron physics is how to interpret the properties and the origin of nuclear force. Nuclear force is in principle the manifestation of dynamics of quarks and gluons but no trial has been successful yet in describing the nuclear force by using QCD, the fundamental theory of the strong interactions. Phenomenon related to the chiral symmetry and the spontaneous breaking of the chiral symmetry is one of the important phenomena for the understanding of hadron physics. Nambu-Jona-Lasinio (NJL) model is one of the quark system models to explain the phenomena concerning the chiral symmetry. Although the method to deduce the Lagrangian describing mesons by applying the path integral to NJL model has been well known as the bosonization, it has been difficult to extend it to baryons because baryons are three-body system. In this paper, a method is reported to deduce Lagrangian which describes baryon-meson from quark-diquark Lagrangian by assuming that baryons are the bound states of quark and diquark. (S. Funahashi)

Nuclear structure at high and very high spin theoretical description

International Nuclear Information System (INIS)

Szymanski, Z.

1983-11-01

When the existence of nuclear shell structure is ignored and nuclear motion is assumed to be classical we may expect that the nuclear rotation resembles that of a liquid drop. Energy of the nucleus can be thus considered as a sum of three terms: surface energy, Coulomb energy and rotational energy. Nuclear moment of inertia is assumed to be that of a rigid-body. The results of a calculation of the energy surfaces in rotating nuclei by Cohen, Plasil and Swiatecki are discussed. Cranking procedure is analysed as a tool to investigate nucleonic orbits in a rotating nuclear potential. Some predictions concerning the possible onset of a superdeformed phase are given. The structure of nuclear rotation is examined in the presence of the short-range pairing forces that generate the superfluid correlations in the nucleus. Examples of the Bengtsson-Frauendorf plots (quasiparticle energies versus angular velocity of rotation) are given and discussed. The backbending phenomenon is analysed in terms of band crossing. The dependence of the crossing frequency on the pairing-force strength is discussed. Possibilities of the role of new components in the two-body force (quadrupole-pairing) are considered. Possibilities of the phase transition from superfluid to normal states in the nucleus are analysed. The role of the second (dynamic) moment of inertia I(2) in this analysis is discussed. In spherical weekly deformed nuclei (mostly oblate) angular momentum is aligned parallel to the nuclear symmetry axis. Rotation is of non collective origin in this case. Examples of the analysis of nuclear spectra in this case (exhibiting also the isomeric states called yrast (traps)) are given. Possible forms of the collective excitations superimposed on top of the high-spin states are discussed. In particular, the giant resonance excitations formed on top of the high-spin states are considered and their properties discussed

Dynamical arrest in dense short-ranged attractive colloids

International Nuclear Information System (INIS)

Foffi, G; Sciortino, F; Zaccarelli, E; Tartaglia, P

2004-01-01

We study thermodynamic and dynamic properties of model colloidal systems interacting with a hard core repulsion and a short-range attraction, and provide an overall picture of their phase diagrams which shows a very rich phenomenology. We focus on the slow dynamic properties of this model, investigating in detail the glass transition lines (both repulsive and attractive), the glass-glass transitions and the location of the higher order singularities. We discuss the relative location of the glass lines and of the metastable liquid-gas binodal, an issue relevant for the understanding of low density arrested states of matter

Electronically driven short-range lattice instability: Possible role in superconductive pairing

International Nuclear Information System (INIS)

Szasz, A.

1991-01-01

A superconducting pairing mechanism is suggested, mediating by collective and coherent cluster fluctuations in the materials. The model, based on a geometrical frustration, proposes a dynamic effect driven by a special short-range electronic instability. Experimental support for this model is discussed

Will high-resolution global ocean models benefit coupled predictions on short-range to climate timescales?

Science.gov (United States)

Hewitt, Helene T.; Bell, Michael J.; Chassignet, Eric P.; Czaja, Arnaud; Ferreira, David; Griffies, Stephen M.; Hyder, Pat; McClean, Julie L.; New, Adrian L.; Roberts, Malcolm J.

2017-12-01

As the importance of the ocean in the weather and climate system is increasingly recognised, operational systems are now moving towards coupled prediction not only for seasonal to climate timescales but also for short-range forecasts. A three-way tension exists between the allocation of computing resources to refine model resolution, the expansion of model complexity/capability, and the increase of ensemble size. Here we review evidence for the benefits of increased ocean resolution in global coupled models, where the ocean component explicitly represents transient mesoscale eddies and narrow boundary currents. We consider lessons learned from forced ocean/sea-ice simulations; from studies concerning the SST resolution required to impact atmospheric simulations; and from coupled predictions. Impacts of the mesoscale ocean in western boundary current regions on the large-scale atmospheric state have been identified. Understanding of air-sea feedback in western boundary currents is modifying our view of the dynamics in these key regions. It remains unclear whether variability associated with open ocean mesoscale eddies is equally important to the large-scale atmospheric state. We include a discussion of what processes can presently be parameterised in coupled models with coarse resolution non-eddying ocean models, and where parameterizations may fall short. We discuss the benefits of resolution and identify gaps in the current literature that leave important questions unanswered.

The pitfalls of short-range endemism: high vulnerability to ecological and landscape traps

Directory of Open Access Journals (Sweden)

Leanda D. Mason

2018-05-01

Full Text Available Ecological traps attract biota to low-quality habitats. Landscape traps are zones caught in a vortex of spiralling degradation. Here, we demonstrate how short-range endemic (SRE traits may make such taxa vulnerable to ecological and landscape traps. Three SRE species of mygalomorph spider were used in this study: Idiommata blackwalli, Idiosoma sigillatum and an undescribed Aganippe sp. Mygalomorphs can be long-lived (>43 years and select sites for permanent burrows in their early dispersal phase. Spiderlings from two species, I. blackwalli (n = 20 and Aganippe sp. (n = 50, demonstrated choice for microhabitats under experimental conditions, that correspond to where adults typically occur in situ. An invasive veldt grass microhabitat was selected almost exclusively by spiderlings of I. sigillatum. At present, habitat dominated by veldt grass in Perth, Western Australia, has lower prey diversity and abundance than undisturbed habitats and therefore may act as an ecological trap for this species. Furthermore, as a homogenising force, veldt grass can spread to form a landscape trap in naturally heterogeneous ecosystems. Selection of specialised microhabitats of SREs may explain high extinction rates in old, stable landscapes undergoing (human-induced rapid change.

Identification and insertion polymorphisms of short interspersed nuclear elements (SINEs) in Brassica genomes

International Nuclear Information System (INIS)

Nouroz, F.; Naveed, M.

2018-01-01

The non-LTR retrotransposons (retroposons) are abundant in plant genomes including members of Brassicaceae. Of the retroposons, long interspersed nuclear elements (LINEs) are more copious followed by short interspersed nuclear elements (SINEs) in sequenced eukaryotic genomes. The SINEs are short elements and ranged from 100-500 bps flanked by variable sized target site duplications, 5' tRNA region with polymerase III promoter, internal tRNA unrelated region, 3' LINEs derived region and a poly adenosine tail. Different computational approaches were used for the identification and characterization of SINEs, while PCR was used to detect the SINEs insertion polymorphisms in various Brassica genotypes. Ten previously unidentified families of SINEs were identified and characterized from Brassica genomes. The structural features of these SINEs were studied in detail, which showed typical SINE features displaying small sizes, target site duplications, head regions, internal regions (body) of variable sizes and a poly (A) tail at the 3' terminus. The elements from various families ranged from 206-558 bp, where BoSINE2 family displayed smallest SINE element (206 bp), while larger members belonged to BoSINE9 family (524-558 bp). The distribution and abundance of SINEs in various Brassica species and genotypes (40) at a particular site/locus were investigated by SINEs based PCR markers. Various SINE insertion polymorphisms were detected from different genotypes, where higher PCR bands amplified the SINE insertions, while lower bands amplified the pre-insertion sites (flanking regions). The analysis of Brassica SINEs copy numbers from 10 identified families revealed that around 860 and 1712 copies of SINEs were calculated from B. rapa and B. oleracea Whole-genome shotgun contigs (WGS) respectively. Analysis of insertion sites of Brassica SINEs revealed that the members from all 10 SINE families had shown an insertion preference in AT rich regions. The present

Short, intermediate and long range order in amorphous ices

Science.gov (United States)

Martelli, Fausto; Torquato, Salvatore; Giovanbattista, Nicolas; Car, Roberto

Water exhibits polyamorphism, i.e., it exists in more than one amorphous state. The most common forms of glassy water are the low-density amorphous (LDA) and the high-density amorphous (HDA) ices. LDA, the most abundant form of ice in the Universe, transforms into HDA upon isothermal compression. We model the transformation of LDA into HDA under isothermal compression with classical molecular dynamics simulations. We analyze the molecular structures with a recently introduced scalar order metric to measure short and intermediate range order. In addition, we rank the structures by their degree of hyperuniformity, i.e.,the extent to which long range density fluctuations are suppressed. F.M. and R.C. acknowledge support from the Department of Energy (DOE) under Grant No. DE-SC0008626.

Nuclear dynamics with the (finite range) Gogny force: flow effects

International Nuclear Information System (INIS)

Sebille, F.; Royer, G.; Schuck, P.; Gregoire, C.

1988-01-01

We introduce for the first time the effective finite range interaction of Gogny in the semi-classical description of heavy ion reactions based on the Landau-Vlasov equation. The characteristics of the flow for heavy ion collisions are studied as functions of the incident energy, the impact parameter and the mass number. The momentum dependence in the mean field together with the non linearities in the collision kernel decrease the flow in contradiction with other calculations; the origins of this discrepancy are studied in details

Range of Motion of the Ankle According to Pushing Force, Gender and Knee Position.

Science.gov (United States)

Cho, Kang Hee; Jeon, Yumi; Lee, Hyunkeun

2016-04-01

To investigate the difference of range of motion (ROM) of ankle according to pushing force, gender and knee position. One hundred and twenty-eight healthy adults (55 men, 73 women) between the ages of 20 and 51, were included in the study. One examiner measured the passive range of motion (PROM) of ankle by Dualer IQ Inclinometers and Commander Muscle Testing. ROM of ankle dorsiflexion (DF) and plantarflexion (PF) according to change of pushing force and knee position were measured at prone position. There was significant correlation between ROM and pushing force, the more pushing force leads the more ROM at ankle DF and ankle PF. Knee flexion of 90° position showed low PF angle and high ankle DF angle, as compared to the at neutral position of knee joint. ROM of ankle DF for female was greater than for male, with no significant difference. ROM of ankle PF for female was greater than male regardless of the pushing force. To our knowledge, this is the first study to assess the relationship between pushing force and ROM of ankle joint. There was significant correlation between ROM of ankle and pushing force. ROM of ankle PF for female estimated greater than male regardless of the pushing force and the number of measurement. The ROM of the ankle is measured differently according to the knee joint position. Pushing force, gender and knee joint position are required to be considered when measuring the ROM of ankle joint.

Microscopic nucleon spectral function for finite nuclei featuring two- and three-nucleon short-range correlations: The model versus ab initio calculations for three-nucleon systems

Science.gov (United States)

Ciofi degli Atti, Claudio; Mezzetti, Chiara Benedetta; Morita, Hiko

2017-04-01

Background: Two-nucleon (2 N ) short-range correlations (SRC) in nuclei have been recently thoroughly investigated, both theoretically and experimentally and the study of three-nucleon (3 N ) SRC, which could provide important information on short-range hadronic structure, is underway. Novel theoretical ideas concerning 2 N and 3 N SRC are put forward in the present paper. Purpose: The general features of a microscopic one-nucleon spectral function which includes the effects of both 2 N and 3 N SRC and its comparison with ab initio spectral functions of the three-nucleon systems are illustrated. Methods: A microscopic and parameter-free one-nucleon spectral function expressed in terms of a convolution integral involving ab initio relative and center-of-mass (c.m.) momentum distributions of a 2 N pair and aimed at describing two- and three-nucleon short-range correlations, is obtained by using: (i) the two-nucleon momentum distributions obtained within ab initio approaches based upon nucleon-nucleon interactions of the Argonne family; (ii) the exact relation between one- and two-nucleon momentum distributions; (iii) the fundamental property of factorization of the nuclear wave function at short internucleon ranges. Results: The comparison between the ab initio spectral function of 3He and the one based upon the convolution integral shows that when the latter contains only two-nucleon short-range correlations the removal energy location of the peaks and the region around them exhibited by the ab initio spectral function are correctly predicted, unlike the case of the high and low removal energy tails; the inclusion of the effects of three-nucleon correlations brings the convolution model spectral function in much better agreement with the ab initio one; it is also found that whereas the three-nucleon short-range correlations dominate the high energy removal energy tail of the spectral function, their effects on the one-nucleon momentum distribution are almost one

Short range spread-spectrum radiolocation system and method

Science.gov (United States)

Smith, Stephen F.

2003-04-29

A short range radiolocation system and associated methods that allow the location of an item, such as equipment, containers, pallets, vehicles, or personnel, within a defined area. A small, battery powered, self-contained tag is provided to an item to be located. The tag includes a spread-spectrum transmitter that transmits a spread-spectrum code and identification information. A plurality of receivers positioned about the area receive signals from a transmitting tag. The position of the tag, and hence the item, is located by triangulation. The system employs three different ranging techniques for providing coarse, intermediate, and fine spatial position resolution. Coarse positioning information is provided by use of direct-sequence code phase transmitted as a spread-spectrum signal. Intermediate positioning information is provided by the use of a difference signal transmitted with the direct-sequence spread-spectrum code. Fine positioning information is provided by use of carrier phase measurements. An algorithm is employed to combine the three data sets to provide accurate location measurements.

Critical temperature of liquid-gas phase transition for hot nuclear matter and three-body force effect

International Nuclear Information System (INIS)

Zuo Wei; Lu Guangcheng; Li Zenghua; Luo Peiyan; Chinese Academy of Sciences, Beijing

2005-01-01

The finite temperature Brueckner-Hartree-Fock (FTBHF) approach is extended by introducing a microscopic three-body force. Within the extended approach, the three-body force effects on the equation of state of hot nuclear matter and its temperature dependence have been investigated. The critical properties of the liquid-gas phase transition of hot nuclear matter have been calculated. It is shown that the three-body force provides a repulsive contribution to the equation of state of hot nuclear matter. The repulsive effect of the three-body force becomes more pronounced as the density and temperature increase and consequently inclusion of the three-body force contribution in the calculation reduces the predicted critical temperature from about 16 MeV to about 13 MeV. By separating the contribution originated from the 2σ-exchange process coupled to the virtual excitation of a nucleon-antinucleon pair from the full three-body force, the connection between the three-body force effect and the relativistic correction from the Dirac-Brueckner-Hartree-Fock has been explored. It turns out that the contribution of the 2σ-N(N-bar) part is more repulsive than that of the full three-body force and the calculated critical temperature is about 11 MeV if only the 2σ-N(N-bar) component of the three-body force is included which is lower than the value obtained in the case of including the full three-body force and is close to the value predicted by the Dirac-Brueckner-Hartree-Fock (DBHF) approach. Our result provides a reasonable explanation for the discrepancy between the values of critical temperature predicted from the FTBHF approach including the three-body force and the DBHF approach. (authors)

Possible manifestation of long range forces in high energy hadron collisions

International Nuclear Information System (INIS)

Kuraev, Eh.A.; Ferro, P.; Trentadue, L.

1997-01-01

Pion-pion and photon-photon scattering are discussed.. We obtain, starting from the impact representation introduced by Cheng and Wu a new contribution to the high energy hadron-hadron scattering amplitude for small transferred momentum q 2 of the form is (q 2 /m 4 )ln(-q 2 /m 2 ). This behaviour may be interpreted as a manifestation of long transverse-range forces between hadrons which, for ρ>> m -1 fall off as ρ -4 . We consider the examples of pion and photon scattering with photons converted in the intermediate state to two pairs of quarks interacting by exchanging two gluon colorless state. A phenomenological approach for proton impact factor is used to analyze proton-proton scattering. The analysis of the lowest order radiative corrections for the case of photon-photon scattering is done. We discuss the possibility of observing the effects of these long range forces

Effect of long-range repulsive Coulomb interactions on packing structure of adhesive particles.

Science.gov (United States)

Chen, Sheng; Li, Shuiqing; Liu, Wenwei; Makse, Hernán A

2016-02-14

The packing of charged micron-sized particles is investigated using discrete element simulations based on adhesive contact dynamic model. The formation process and the final obtained structures of ballistic packings are studied to show the effect of interparticle Coulomb force. It is found that increasing the charge on particles causes a remarkable decrease of the packing volume fraction ϕ and the average coordination number 〈Z〉, indicating a looser and chainlike structure. Force-scaling analysis shows that the long-range Coulomb interaction changes packing structures through its influence on particle inertia before they are bonded into the force networks. Once contact networks are formed, the expansion effect caused by repulsive Coulomb forces are dominated by short-range adhesion. Based on abundant results from simulations, a dimensionless adhesion parameter Ad*, which combines the effects of the particle inertia, the short-range adhesion and the long-range Coulomb interaction, is proposed and successfully scales the packing results for micron-sized particles within the latest derived adhesive loose packing (ALP) regime. The structural properties of our packings follow well the recent theoretical prediction which is described by an ensemble approach based on a coarse-grained volume function, indicating some kind of universality in the low packing density regime of the phase diagram regardless of adhesion or particle charge. Based on the comprehensive consideration of the complicated inter-particle interactions, our findings provide insight into the roles of short-range adhesion and repulsive Coulomb force during packing formation and should be useful for further design of packings.

Japanese Nuclear Accident and U.S. Response

International Nuclear Information System (INIS)

Douet, Randy

2011-01-01

U.S. Government response to the Fukushima accident: • Multi-agency task force (Nuclear Regulatory Commission, Department of Energy, Department of Defense) supporting Japan recovery efforts; • President Obama directed the NRC to perform a comprehensive review of U.S. reactors; • NRC established agency task force to develop lessons learned from Fukushima Daiichi accident to provide short-term and long-term analysis of the events

[Hyperfine structure and isotope shift measurements of short lived elements by laser spectroscopy

International Nuclear Information System (INIS)

Schuessler, H.A.

1986-01-01

The aim of this research is to determine nuclear moments and charge distributions of short-lived isotopes produced both on-line and off-line to a nuclear facility. These measurements give detailed information on the nuclear force and are used to test current nuclear models. The small amounts of nuclei which can be produced off stability constitute the challenge in these experiments. Presently mainly neutron-rich isotopes are being studied by three ultrasensitive high-resolution laser techniques. These are collinear fast ion-beam laser spectroscopy, stored-ion laser spectroscopy and fluorescence spectroscopy. 5 figs

A review on the long-range strategy of nuclear power development

International Nuclear Information System (INIS)

An, Shigehiro; Kondo, Shunsuke; Ishida, Hiroshi.

1979-01-01

Nuclear power generation in Japan is proceeding steadily, such as the world's second in power generating capacity and the nation's own development of power reactors. Meanwhile, however, there are number of problems for future solution, like the establishment of nuclear fuel cycle, before nuclear energy is fully harnessed. Looking as far ahead as the 21st century, the long-range strategy of nuclear power development is reviewed: politics on uranium supply outlook, a compromise between uranium enrichment and nuclear nonproliferation, LWR technology with safety, FBR development scheme, uranium resources saving and heavy water reactor, HTGR development, a 2nd fuel reprocessing plant, high level wastes management, reactors decommissioning, research in nuclear energy development, and fostering of a nuclear power industry. (J.P.N.)

Nuclear proliferation: what are the limits to Iran forced march?

International Nuclear Information System (INIS)

Drouhaud, P.

2006-01-01

Since 9 March 2006 the United Nations Security Council has been examining the report on Iran by the IAEA, which noted the failure of years of negotiations between Iran and the EU3 nations representing Europe (Britain, France and Germany). Following the June 2005 election of Mr Ahmadinejad, relations with the international community have become notably tense, with the resumption of nuclear activity (reprocessing, enrichment, etc.). The West is now convinced that this civil programme is enabling Iran to conceal a military programme, which, if it is completed, will shatter relationships, political and economic, in an area of strategic importance. The tensions generated by the policy adopted by Iran, in its forced march towards a nuclear capability, brings to the fore the nuclear proliferation problem, which is likely to become one of the major threats of the twenty-first century. (author)

Introduction of Thorium in the Nuclear Fuel Cycle. Short- to long-term considerations

International Nuclear Information System (INIS)

Allibert, M.; Merle-Lucotte, E.; Ghetta, V.; Ault, T.; Krahn, S.; Wymer, R.; Croff, A.; Baron, P.; Chauvin, N.; Eschbach, R.; Rimpault, G.; Serp, J.; Bergeron, A.; Bromley, B.; Floyd, M.; Hamilton, H.; Hyland, B.; Wojtaszek, D.; McDonald, M.; Collins, E.; Cornet, S.; Michel-Sendis, F.; ); Feinberg, O.; Ignatiev, V.; Hesketh, K.; Kelly, J.F.; Porsch, D.; Vidal, J.; Taiwo, T.; Uhlir, J.; Van Den Durpel, L.; Van Den Eynde, G.; Vitanza, C.; Butler, Gregg; Cornet, Stephanie; Dujardin, Thierry; Greneche, Dominique; Nordborg, Claes; Rimpault, Gerald; Van Den Durpel, Luc; Michel-Sendis, Franco

2015-01-01

Since the beginning of the nuclear era, significant scientific attention has been given to thorium's potential as a nuclear fuel. Although the thorium fuel cycle has never been fully developed, the opportunities and challenges that might arise from the use of thorium in the nuclear fuel cycle are still being studied in many countries and in the context of diverse international programmes around the world. This report provides a scientific assessment of thorium's potential role in nuclear energy both in the short to longer term, addressing diverse options, potential drivers and current impediments to be considered if thorium fuel cycles are to be pursued. (authors)

EXAFS, Determination of Short Range Order and Local Structures in Materials

NARCIS (Netherlands)

Koningsberger, D.C.; Prins, R.

1981-01-01

Extended X-ray Absorption Fine Structure (EXAFS) is a powerful method of determining short range order and local structures in materials using X-ray photons produced by a synchrotron light source, or in-house by a high intensity rotating anode X-ray generator. The technique has provided valuable

Investigations of multiphoton excitation and ionization in a short range potential

International Nuclear Information System (INIS)

Susskind, S.M.; Cowley, S.C.; Valeo, E.J.

1989-02-01

We introduce an approach to the study of excitation and ionization for a system with a short range potential. In particular, analytical and numerical results are presented for the multiphoton ionization rate, under strong field conditions, of an electron confined by a δ-function potential. 9 refs., 3 figs

Investigations of multiphoton excitation and ionization in a short range potential

Energy Technology Data Exchange (ETDEWEB)

Susskind, S.M.; Cowley, S.C.; Valeo, E.J.

1989-02-01

We introduce an approach to the study of excitation and ionization for a system with a short range potential. In particular, analytical and numerical results are presented for the multiphoton ionization rate, under strong field conditions, of an electron confined by a delta-function potential. 9 refs., 3 figs.

Nuclear physics. Momentum sharing in imbalanced Fermi systems.

Science.gov (United States)

Hen, O; Sargsian, M; Weinstein, L B; Piasetzky, E; Hakobyan, H; Higinbotham, D W; Braverman, M; Brooks, W K; Gilad, S; Adhikari, K P; Arrington, J; Asryan, G; Avakian, H; Ball, J; Baltzell, N A; Battaglieri, M; Beck, A; May-Tal Beck, S; Bedlinskiy, I; Bertozzi, W; Biselli, A; Burkert, V D; Cao, T; Carman, D S; Celentano, A; Chandavar, S; Colaneri, L; Cole, P L; Crede, V; D'Angelo, A; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dugger, M; Dupre, R; Egiyan, H; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Fedotov, G; Fegan, S; Forest, T; Garillon, B; Garcon, M; Gevorgyan, N; Ghandilyan, Y; Gilfoyle, G P; Girod, F X; Goetz, J T; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hanretty, C; Hattawy, M; Hicks, K; Holtrop, M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkanov, B I; Isupov, E L; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Klein, F J; Koirala, S; Korover, I; Kuhn, S E; Kubarovsky, V; Lenisa, P; Levine, W I; Livingston, K; Lowry, M; Lu, H Y; MacGregor, I J D; Markov, N; Mayer, M; McKinnon, B; Mineeva, T; Mokeev, V; Movsisyan, A; Munoz Camacho, C; Mustapha, B; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Pappalardo, L L; Paremuzyan, R; Park, K; Pasyuk, E; Phelps, W; Pisano, S; Pogorelko, O; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Rimal, D; Ripani, M; Ritchie, B G; Rizzo, A; Rosner, G; Roy, P; Rossi, P; Sabatié, F; Schott, D; Schumacher, R A; Sharabian, Y G; Smith, G D; Shneor, R; Sokhan, D; Stepanyan, S S; Stepanyan, S; Stoler, P; Strauch, S; Sytnik, V; Taiuti, M; Tkachenko, S; Ungaro, M; Vlassov, A V; Voutier, E; Walford, N K; Wei, X; Wood, M H; Wood, S A; Zachariou, N; Zana, L; Zhao, Z W; Zheng, X; Zonta, I

2014-10-31

The atomic nucleus is composed of two different kinds of fermions: protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority of fermions (usually neutrons) to have a higher average momentum. Our high-energy electron-scattering measurements using (12)C, (27)Al, (56)Fe, and (208)Pb targets show that even in heavy, neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few-body systems to neutron stars and may also be observable experimentally in two-spin-state, ultracold atomic gas systems. Copyright © 2014, American Association for the Advancement of Science.

Benchmarking of thermalhydraulic loop models for lead-alloy-cooled advanced nuclear energy systems. Phase I: Isothermal forced convection case

International Nuclear Information System (INIS)

2012-06-01

Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Scientific Issues of the Fuel Cycle (WPFC) has been established to co-ordinate scientific activities regarding various existing and advanced nuclear fuel cycles, including advanced reactor systems, associated chemistry and flowsheets, development and performance of fuel and materials and accelerators and spallation targets. The WPFC has different expert groups to cover a wide range of scientific issues in the field of nuclear fuel cycle. The Task Force on Lead-Alloy-Cooled Advanced Nuclear Energy Systems (LACANES) was created in 2006 to study thermal-hydraulic characteristics of heavy liquid metal coolant loop. The objectives of the task force are to (1) validate thermal-hydraulic loop models for application to LACANES design analysis in participating organisations, by benchmarking with a set of well-characterised lead-alloy coolant loop test data, (2) establish guidelines for quantifying thermal-hydraulic modelling parameters related to friction and heat transfer by lead-alloy coolant and (3) identify specific issues, either in modelling and/or in loop testing, which need to be addressed via possible future work. Nine participants from seven different institutes participated in the first phase of the benchmark. This report provides details of the benchmark specifications, method and code characteristics and results of the preliminary study: pressure loss coefficient and Phase-I. A comparison and analysis of the results will be performed together with Phase-II

The theory of nuclear forces: Is the never-ending story coming to an end?

International Nuclear Information System (INIS)

Machleidt, R.

2007-01-01

I review the recent progress in our understanding of nuclear forces in terms of an effective field theory (EFT) for low-energy QCD and put this progress into historical perspective. This is followed by an assessment of the current status of EFT based nuclear potentials. In concluding, I will summarize some unresolved issues

QCD and short-range nuclear phenomena

International Nuclear Information System (INIS)

Frankfurt, L.L.; Strikman, M.I.

1981-01-01

In terms of pertubative QCD we estimate the shape of the high-momentum tail of the nucleus wave function. We derive QCD predictions for the yield of leading particles in nucleus fragmentation processes. The predicted yield is much larger than the expectations of the quark counting rules. Obtained formulae are in reasonable agreement with the momentum and angular dependence of cumulative particle production. We derive general expressions for deep inelastic lepton-nucleus scattering using the LSZ representation for the amplitude and use it to calculate the scaling violation in high Q 2 near threshold eD scattering at x >= 1. It is shown that the existence of few-nucleon correlations explains the large cross section of the deep inelastic process e + 3 He → e +... and leads to a larger effect for heavier nuclei. We demonstrate that the observed features of ν(anti ν) + A → μsup(+-) + backward proton + X data indicate the dominance of few-nucleon correlations in the nucleus wave function over average field configurations at momenta > 0.4 GeV/c. Implications of these data for the magnitude of smearing in deep inelastic processes are also considered. (orig.)

Age differences in visual search for compound patterns: long- versus short-range grouping.

Science.gov (United States)

Burack, J A; Enns, J T; Iarocci, G; Randolph, B

2000-11-01

Visual search for compound patterns was examined in observers aged 6, 8, 10, and 22 years. The main question was whether age-related improvement in search rate (response time slope over number of items) was different for patterns defined by short- versus long-range spatial relations. Perceptual access to each type of relation was varied by using elements of same contrast (easy to access) or mixed contrast (hard to access). The results showed large improvements with age in search rate for long-range targets; search rate for short-range targets was fairly constant across age. This pattern held regardless of whether perceptual access to a target was easy or hard, supporting the hypothesis that different processes are involved in perceptual grouping at these two levels. The results also point to important links between ontogenic and microgenic change in perception (H. Werner, 1948, 1957).

Short-term versus long-term contracting for uranium enrichment services

International Nuclear Information System (INIS)

Rudy, G.P.

1990-01-01

The US Department of Energy (US DOE) is the world's largest and most experienced supplier of uranium enrichment services. Through the late 1970s and early 1980s, emerging market forces transformed what was once a monopoly into a highly competitive industry. In the early 1980's the DOE lost market share. But as we enter the 1990s, new market forces have emerged. The US DOE believes a responsible balance between long-term and short-term contracting will be the key to success and the key to assuring the long-term health and reliability of the nuclear fuel industry. The US DOE intends to be in this nuclear business for a long time and will continue to offer reliable and responsive services second to none

Neutrino-Pair Exchange Long-Range Force Between Aggregate Matter

OpenAIRE

Segarra, A.

2016-01-01

We study the long-range force arising between two neutral---of electric charge---aggregates of matter due to a neutrino-pair exchange, in the limit of zero neutrino mass. The conceptual basis for the construction of the effective potential comes from the coherent scattering amplitude at low values of t. This amplitude is obtained using the methodology of an unsubtracted dispersion relation in t at threshold for s, where (s, t) are the Lorentz invariant scattering variables. The ultraviolet be...

The Coulomb-nuclear force interference in the system 32S + 60Ni

International Nuclear Information System (INIS)

Dannhaeuser, G.

1980-01-01

For the reaction 60 Ni( 32 S, 32 S*) 60 Ni* using particle-γ-coincidences the excitation functions of 32 S(2 + 1 ) and 60 Ni(2 + 1 ) for projectile energies of 70-100 MeV as well as with Si single counters the angular distribution of the elastically and inelastically scattered 32 S ions for incident energies of 90, 95, and 100 MeV were measured. A comparison of the measurements with the results of different computer codes led to following results: 1.) At the determination of the static quadrupole moment Q 2 of 32 S using the reorientation effect the influence of the nuclear force can be neglected for projectile energies Esub(P) 32 S the value Q 2 = -0.18 +- 0.04 eb was found. (Hereby destructive interference with the virtual excitation of the 2 + 2 -state is assumed). 3.) For projectile energies Esub(P) >= 72 MeV at which the excitation by nuclear forces was small against the Coulomb excitation, an evaluation of the excitation function of 32 S(2 + 1 ) by the semiclassical code NCL, which regards the influence of the nuclear interaction approximatively, yielded values for the static quadrupole moment, which agree within the measurement errors with the above value. 4.) For the quantitative analysis of the measured angular distributions a quantum mechanical CC-code was required. 5.) Using the semiclassical CC-code NCL an illustrative and detailed interpretation of the excitation functions of 32 S(2 + 1 ) and 60 Ni(2 + 1 ) could be given. 6.) The code NCL allows the study of the influence of the Coulomb-nuclear force interference on the temporal behaviour of the excitation process. 7.) Using the code NCL the angular distribution of the decay γ quanta for a fixed particle-scattering angle theta approx. 0 in dependence on the incident energy was calculated. (orig.) [de

Three-body forces: a status report

International Nuclear Information System (INIS)

Coon, S.A.

1976-01-01

Real three-body forces due to meson exchange are distinguished from effective three-body interactions of a nuclear Hamiltonian. The long-range part of the real three-body force is proportional to the off-mass-shell sup(PI)N scattering amplitude. Its contribution to the binding energy of nuclear matter is quite dependent upon the treatment of correlations (due to the two-body potential) in the three-body wave function. A recent improvemrnt in the amplitude implies a very small contribution. But, a recent improvement in the treatment of correlations implies a large contribution. Work towards including both these improvements in a single calculation is in progress. (author)

Solvent-shared pairs of densely charged ions induce intense but short-range supra-additive slowdown of water rotation.

Science.gov (United States)

Vila Verde, Ana; Santer, Mark; Lipowsky, Reinhard

2016-01-21

The question "Can ions exert supra-additive effects on water dynamics?" has had several opposing answers from both simulation and experiment. We address this ongoing controversy by investigating water reorientation in aqueous solutions of two salts with large (magnesium sulfate) and small (cesium chloride) effects on water dynamics using molecular dynamics simulations and classical, polarizable models. The salt models are reparameterized to reproduce properties of both dilute and concentrated solutions. We demonstrate that water rotation in concentrated MgSO4 solutions is unexpectedly slow, in agreement with experiment, and that the slowdown is supra-additive: the observed slowdown is larger than that predicted by assuming that the resultant of the extra forces induced by the ions on the rotating water molecules tilts the free energy landscape associated with water rotation. Supra-additive slow down is very intense but short-range, and is strongly ion-specific: in contrast to the long-range picture initially proposed based on experiment, we find that intense supra-additivity is limited to water molecules directly bridging two ions in solvent-shared ion pair configuration; in contrast to a non-ion-specific origin to supra-additive effects proposed from simulations, we find that the magnitude of supra-additive slowdown strongly depends on the identity of the cations and anions. Supra-additive slowdown of water dynamics requires long-lived solvent-shared ion pairs; long-lived ion pairs should be typical for salts of multivalent ions. We discuss the origin of the apparent disagreement between the various studies on this topic and show that the short-range cooperative slowdown scenario proposed here resolves the existing controversy.

Report of the Secretary of Defense Task Force on DoD Nuclear Weapons Management. Phase II: Review of the DoD Nuclear Mission

National Research Council Canada - National Science Library

Schlesinger, James R; Carns, Michael P; Crouch, II, J. D; Gansler, Jacques S; Giambastiani, Jr., Edmund P; Hamre, John J; Miller, Franklin C; Williams, Christopher A; Blackwell, Jr, James A

2008-01-01

...). This report covers Phase II findings and recommendations. In Phase II, the Task Force found that the lack of interest in and attention to the nuclear mission and nuclear deterrence, as discussed in our Phase I report, go well beyond the Air...

Short-range order in InSb amorphized under ion bombardment

International Nuclear Information System (INIS)

Pavlov, P.V.; Tetel'baum, D.I.; Gerasimov, A.I.

1979-01-01

The investigation of short-range order is carried out in polycrystal InSb films, irradiated with Ne + ions with E=150 keV and with the 2x10 15 ion/cm 2 dose. The data are obtained testifying to the film amorphization, the cause of which is the defect storage but not the local melting. Stability of the obtained amorphous phase at the room temperature is noted

Short-range quantitative precipitation forecasting using Deep Learning approaches

Science.gov (United States)

Akbari Asanjan, A.; Yang, T.; Gao, X.; Hsu, K. L.; Sorooshian, S.

2017-12-01

Predicting short-range quantitative precipitation is very important for flood forecasting, early flood warning and other hydrometeorological purposes. This study aims to improve the precipitation forecasting skills using a recently developed and advanced machine learning technique named Long Short-Term Memory (LSTM). The proposed LSTM learns the changing patterns of clouds from Cloud-Top Brightness Temperature (CTBT) images, retrieved from the infrared channel of Geostationary Operational Environmental Satellite (GOES), using a sophisticated and effective learning method. After learning the dynamics of clouds, the LSTM model predicts the upcoming rainy CTBT events. The proposed model is then merged with a precipitation estimation algorithm termed Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) to provide precipitation forecasts. The results of merged LSTM with PERSIANN are compared to the results of an Elman-type Recurrent Neural Network (RNN) merged with PERSIANN and Final Analysis of Global Forecast System model over the states of Oklahoma, Florida and Oregon. The performance of each model is investigated during 3 storm events each located over one of the study regions. The results indicate the outperformance of merged LSTM forecasts comparing to the numerical and statistical baselines in terms of Probability of Detection (POD), False Alarm Ratio (FAR), Critical Success Index (CSI), RMSE and correlation coefficient especially in convective systems. The proposed method shows superior capabilities in short-term forecasting over compared methods.

Attractive short-range interatomic potential in the lattice dynamics of niobium and tantalum

International Nuclear Information System (INIS)

Onwuagba, B.N.; Pal, S.

1987-01-01

It is shown in the framework of the pseudopotential approach that there is a sizable attractive short-range component of the interatomic potential due to the s-d interaction which has the same functional form in real space as the Born-Mayer repulsion due to the overlap of core electron wave functions centred on neighbouring ions. The magnitude of this attractive component is such as to completely cancel the conventional Born-Mayer repulsion, making the resultant short-range interatomic potential attractive rather than repulsive. Numerical calculations show that the attractive interatomics potential, which represents the local-field correction, leads to a better understanding of the occurrence of the soft modes in the phonon dispersion curves of niobium and tantalum

Transformation of Taiwan’s Reserve Force

Science.gov (United States)

2017-01-01

benefited tremen- dously from their deep knowledge across the range of issues associated with reserve force reforms generally, and reserve force...Penghu Wude Joint Counter Amphibious Exercise [澎湖五德聯信聯合反登陸操演],” 2013. 18 For details on Taiwan’s short-range air defense capabilities, see Kuo Wen ...opinion/national-service-for-the-21st-century Kuo Wen -liang, National Defense Education: Defense Science and Technology [全民國防教育國防科技], Taipei: NWCD

Interim report on long range plan for nuclear physics

International Nuclear Information System (INIS)

Anon.

1995-01-01

The interim report on the updated NSAC Long Range Plan for Nuclear Physics will be presented to the community for discussion and comment before submission to the funding agencies. The presentation will be coordinated by E. Moniz chair of NSAC

Short and medium range structures of 80GeSe2–20Ga2Se3 chalcogenide glasses

Science.gov (United States)

Petracovschi, Elena; Calvez, Laurent; Cormier, Laurent; Le Coq, David; Du, Jincheng

2018-05-01

The short and medium range structures of 80GeSe2–20Ga2Se3 (or Ge23.5Ga11.8Se64.7) chalcogenide glasses have been studied by combining ab initio molecular dynamics (AIMD) simulations and experimental neutron diffraction studies. The structure factor and total correlation function were calculated from glass structures generated from AIMD simulations and compared with neutron diffraction experiments showing reasonable agreement. The atomic structures of ternary chalcogenide glasses were analyzed in detail, and it was found that gallium atoms are four-fold coordinated by selenium (Se) and form [GaSe4] tetrahedra. Germanium atoms on average also have four-fold coordination, among which Se is 3.5 with the remaining being Ge–Ge homo-nuclear bonds. Ga and Ge tetrahedra link together mainly through corner-sharing and some edge-sharing of Se. No homo-nuclear bonds were observed among Ga atoms or between Ge and Ga. In addition, Se–Se homo-nuclear bonds and Se chains with various lengths were observed. A small fraction of Se atom triclusters that bond to three cations of Ge and Ga were also observed, confirming earlier proposals from 77Se solid state nuclear magnetic resonance studies. Furthermore, the electronic structures of ternary chalcogenide glasses were studied in terms of atomic charge and electronic density of states in order to gain insights into the chemical bonding and electronic properties, as well as to provide an explanation of the observed atomic structures in these ternary chalcogenide glasses.

Freely cooling granular gases with short-ranged attractive potentials

Energy Technology Data Exchange (ETDEWEB)

Murphy, Eric; Subramaniam, Shankar, E-mail: shankar@iastate.edu [Department of Mechanical Engineering, Center for Multiphase Flow Research, Iowa State University, Ames, Iowa 50011 (United States)

2015-04-15

We treat the case of an undriven gas of inelastic hard-spheres with short-ranged attractive potentials via an extension of the pseudo-Liouville operator formalism. New evolution equations for the granular temperature and coordination number are obtained. The granular temperature exhibits deviation from both Haff’s law and the case of long-ranged potentials. We verify this departure using soft-sphere discrete element method simulations. Excellent agreement is found for the duration of the simulation even beyond where exclusively binary collisions are expected. Simulations show the emergence of strong spatial-velocity correlations on the length scale of the last peak in the pair-correlation function but do not show strong correlations beyond this length scale. We argue that molecular chaos may remain an adequate approximation if the system is modelled as a Smoluchowski type equation with aggregation and break-up processes.

Study of an Ising model with competing long- and short-range interactions

International Nuclear Information System (INIS)

Loew, U.; Emery, V.J.; Fabricius, K.; Kivelson, S.A.

1994-01-01

A classical spin-one lattice gas model is used to study the competition between short-range ferromagnetic coupling and long-range antiferromagnetic Coulomb interactions. The model is a coarse-grained representation of frustrated phase separation in high-temperature superconductors. The ground states are determined for the complete range of parameters by using a combination of numerical and analytical techniques. The crossover between ferromagnetic and antiferromagnetic states proceeds via a rich structure of highly symmetric striped and checkerboard phases. There is no devil's staircase behavior because mixtures of stripes with different period phase separate

Nuclear matter and electron scattering

Energy Technology Data Exchange (ETDEWEB)

Sick, I [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)

1998-06-01

We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)

Relativistic interpretation of the nature of the nuclear tensor force

Science.gov (United States)

Zong, Yao-Yao; Sun, Bao-Yuan

2018-02-01

The spin-dependent nature of the nuclear tensor force is studied in detail within the relativistic Hartree-Fock approach. The relativistic formalism for the tensor force is supplemented with an additional Lorentz-invariant tensor formalism in the σ-scalar channel, so as to take into account almost fully the nature of the tensor force brought about by the Fock diagrams in realistic nuclei. Specifically, the tensor sum rules are tested for the spin and pseudo-spin partners with and without nodes, to further understand the nature of the tensor force within the relativistic model. It is shown that the interference between the two components of nucleon spinors causes distinct violations of the tensor sum rules in realistic nuclei, mainly due to the opposite signs on the κ quantities of the upper and lower components, as well as the nodal difference. However, the sum rules can be precisely reproduced if the same radial wave functions are taken for the spin/pseudo-spin partners in addition to neglecting the lower/upper components, revealing clearly the nature of the tensor force. Supported by National Natural Science Foundation of China (11375076, 11675065) and the Fundamental Research Funds for the Central Universities (lzujbky-2016-30)

Report of the Task Force on bonding and perpetual care of nuclear licensed activities

International Nuclear Information System (INIS)

Snellings, D.D. Jr.

1975-01-01

The primary concern was to consider the bonding and perpetual care requirements of state-licensed shallow land burial sites used for the disposal of radioactive wastes. The specific charge of the task force was to examine in detail the requirements for establishing bonding and perpetual care programs for all types of licensed nuclear activities and to report the findings of the task force as guidance to assist states in program development. Goals and recommendations of the task force are discussed

On the dynamic fracture toughness and crack tip strain behavior of nuclear pressure vessel steel: Application of electromagnetic force

International Nuclear Information System (INIS)

Yagawa, G.; Yoshimura, S.

1986-01-01

This paper is concerned with the application of the electromagnetic force to the determination of the dynamic fracture toughness of materials. Taken is an edge-cracked specimen which carries a transient electric current and is simply supported in a steady magnetic field. As a result of their interaction, the dynamic electromagnetic force occurs in the whole body of the specimen, which is then deformed to fracture in the opening mode of cracking. Using the electric potential and the J-R curve methods to determine the dynamic crack initiation point in the experiment, together with the finite element method to calculate the extended J-integral with the effects of the electromagnetic force and inertia, the dynamic fracture toughness values of nuclear pressure vessel steel A508 class 3 are evaluated over a wide temperature range from lower to upper shelves. The strain distribution near the crack tip in the dynamic process of fracture is also obtained by applying a computer picture processing. (orig.)

Short-Range Noncontact Sensors for Healthcare and Other Emerging Applications: A Review

Directory of Open Access Journals (Sweden)

Changzhan Gu

2016-07-01

Full Text Available Short-range noncontact sensors are capable of remotely detecting the precise movements of the subjects or wirelessly estimating the distance from the sensor to the subject. They find wide applications in our day lives such as noncontact vital sign detection of heart beat and respiration, sleep monitoring, occupancy sensing, and gesture sensing. In recent years, short-range noncontact sensors are attracting more and more efforts from both academia and industry due to their vast applications. Compared to other radar architectures such as pulse radar and frequency-modulated continuous-wave (FMCW radar, Doppler radar is gaining more popularity in terms of system integration and low-power operation. This paper reviews the recent technical advances in Doppler radars for healthcare applications, including system hardware improvement, digital signal processing, and chip integration. This paper also discusses the hybrid FMCW-interferometry radars and the emerging applications and the future trends.

Three-nucleon forces

International Nuclear Information System (INIS)

Sauer, P.U.

2014-01-01

In this paper, the role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries toward calculationally converged results. Genuine forces make up the Hamiltonian. They represent the chosen underlying dynamics. The hierarchy of contributions arising from genuine two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the description of some observables. Their contributions to observables are small on the scale set by two-nucleon forces. (author)

Lattice QCD simulation of meson exchange forces

International Nuclear Information System (INIS)

Richards, D.G.; Sinclair, D.K.; Sivers, D.

1990-01-01

We present the formalism for investigating the bar Qq bar Qq system in lattice QCD. This system serves as a model for describing exchange forces between heavy, static hadrons. We use this formalism to calculate the exchange potential from gauge configurations which incorporate the effects of dynamical quarks. Our data can be interpreted as giving preliminary results on the range of the nuclear force

Hybrid gesture recognition system for short-range use

Science.gov (United States)

Minagawa, Akihiro; Fan, Wei; Katsuyama, Yutaka; Takebe, Hiroaki; Ozawa, Noriaki; Hotta, Yoshinobu; Sun, Jun

2012-03-01

In recent years, various gesture recognition systems have been studied for use in television and video games[1]. In such systems, motion areas ranging from 1 to 3 meters deep have been evaluated[2]. However, with the burgeoning popularity of small mobile displays, gesture recognition systems capable of operating at much shorter ranges have become necessary. The problems related to such systems are exacerbated by the fact that the camera's field of view is unknown to the user during operation, which imposes several restrictions on his/her actions. To overcome the restrictions generated from such mobile camera devices, and to create a more flexible gesture recognition interface, we propose a hybrid hand gesture system, in which two types of gesture recognition modules are prepared and with which the most appropriate recognition module is selected by a dedicated switching module. The two recognition modules of this system are shape analysis using a boosting approach (detection-based approach)[3] and motion analysis using image frame differences (motion-based approach)(for example, see[4]). We evaluated this system using sample users and classified the resulting errors into three categories: errors that depend on the recognition module, errors caused by incorrect module identification, and errors resulting from user actions. In this paper, we show the results of our investigations and explain the problems related to short-range gesture recognition systems.

Assessment of Effective Prestressed Force of Nuclear Containment Building using SI Technique

Energy Technology Data Exchange (ETDEWEB)

Lee, H. P.; Jang, J. B.; Hwang, K. M.; Song, Y. C. [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2010-10-15

Bonded tendons have been used in reactor buildings of heavy water reactors and the light water reactors of some nuclear power plants operating in Korea. The assessment of prestressed forces on those bonded tendons is becoming an important issue in assuring their continuous operation beyond their design life. In order to assess the effective prestressed force on the bonded tendon, indirect assessment techniques have been applying to the test beams which were manufactured on construction time. Therefore, this research mainly forced to establish the assessment methodology to measure directly the effective prestressed force on the bonded tendon of containment buildings using System Identification (SI) technique. To accomplish this purpose, simple SI method was proposed and adapted three dimensional finite element analysis of the 1:4 scale prestressed concrete containment vessel (PCCV) tested by Sandia National Laboratory in 2000

Short-arc orbit determination using coherent X-band ranging data

Science.gov (United States)

Thurman, S. W.; Mcelrath, T. P.; Pollmeier, V. M.

1992-01-01

The use of X-band frequencies in ground-spacecraft and spacecraft-ground telecommunication links for current and future robotic interplanetary missions makes it possible to perform ranging measurements of greater accuracy than previously obtained. It is shown that ranging data of sufficient accuracy, when acquired from multiple stations, can sense the geocentric angular position of a distant spacecraft. The application of high-accuracy S/X-band and X-band ranging to orbit determination with relatively short data arcs is investigated in planetary approach and encounter scenarios. Actual trajectory solutions for the Ulysses spacecraft constructed from S/X-band ranging and Doppler data are presented; error covariance calculations are used to predict the performance of X-band ranging and Doppler data. The Ulysses trajectory solutions indicate that the aim point for the spacecraft's February 1992 Jupiter encounter was predicted to a geocentric accuracy of 0.20 to 0.23/microrad. Explicit modeling of range bias parameters for each station pass is shown to largely remove systematic ground system calibration errors and transmission media effects from the Ulysses range measurements, which would otherwise corrupt the angle finding capabilities of the data. The Ulysses solutions were found to be reasonably consistent with the theoretical results, which suggest that angular accuracies of 0.08 to 0.1/microrad are achievable with X-band ranging.

Lifetimes of #betta#'s and μ's and short-distance nuclear phenomena

International Nuclear Information System (INIS)

Kisslinger, L.S.

1982-06-01

It is shown that short distance phenomena and thus quark structure play vital roles in the theory of #betta# and μ decays in nuclei. A hybrid two-baryon-quark shell model is used to estimate the lifetimes for nonmesonic decays of #betta#'s and μ's in nuclear matter

Implications of QCD for soft hadronic and nuclear processes

International Nuclear Information System (INIS)

Hwa, R.C.

1981-01-01

Physical implications of QCD for strong forces in soft processes are discussed. Topics include long-range force, Van der Waals force, nuclear force, hadron and quark structures. In the absence of a reliable calculational scheme, phenomenological models have been built that incorporate QCD ideas as far as possible. In the framework of those models calculations have been made that provide an understanding of the soft processes in terms of quarks and gluons. We review recent work on nuclear potential, form factors at low Q 2 , pion decay constant, inclusive distribution of low p/sub T/, and radiation length of fast quark in nuclear matter

Origins of the Tactical Nuclear Weapons Modernization Program: 1969-1979

Science.gov (United States)

Yaffe, Michael David

On December 12, 1979, the North Atlantic Treaty Organization decided to deploy new long-range theater nuclear forces, Pershing II and Ground-Launched Cruise Missiles. This marked the first major change in NATO's nuclear stockpile since the adoption of the flexible response strategy in 1967. The decision was controversial inasmuch as the Allies disagreed on the fundamental role of nuclear weapons in this strategy and, thereby, the types and number of weapons required for an effective deterrent posture. Europeans generally preferred long-range weapons capable of striking the Soviet Union and small conventional forces while Americans preferred shorter-range nuclear weapons and a stalwart conventional defense. Thus, the December decision is often described as purely politically motivated, in which the Americans reluctantly acquiesced to a European initiative for long-range weapons, prominently expressed by West German Chancellor Helmut Schmidt in 1977. Recently declassified US government documents reveal, however, that long-range missiles were part of a long-term comprehensive nuclear modernization program conceived in the Pentagon under Defense Secretary James Schlesinger during the period of 1973 through 1975, and presented to skeptical European elites who favored arms control negotiations over costly new deployments. This program was motivated as much by changes in the American national security culture as by an increase in the Soviet military threat to Europe. It was grounded on a clear military rationale: "that a feasible and affordable conventional defense is only possible if NATO has modern nuclear forces" that can effectively hold at risk Warsaw Pact ground and air forces throughout the depth of their employment from the inner-German border to the western military districts of the Soviet Union. When the new US administration in 1977 disagreed with the modernization plan and its rationale, opting instead for more conventional forces, the Allies in a reversal of

Sigma exchange in the nuclear force and effective field theory

International Nuclear Information System (INIS)

Donoghue, John F.

2006-01-01

In the phenomenological description of the nuclear interaction an important role is traditionally played by the exchange of a scalar I=0 meson, the sigma, of mass 500-600 MeV, which however is not seen clearly in the particle spectrum and which has a very ambiguous status in QCD. I show that a remarkably simple and reasonably controlled combination of ingredients can reproduce the features of this part of the nuclear force. The use of chiral perturbation theory calculations for two pion exchange supplemented by the Omnes function for pion rescattering suffices to reproduce the magnitude and shape of the exchange of a supposed σ particle. I also attempt to relate this description to the contact interaction that enters more modern descriptions of the internucleon interaction

U.S. Nuclear Policy, Strategy, and Force Structure: Insights and Issues from the 1994, 2001, and 2010 Nuclear Posture Reviews

Science.gov (United States)

2014-09-01

community.”251 Senator Jeff Sessions, in the April 17, 2013 Hearing to Receive Testimony on Nuclear Forces and Policies, expressed concern that allies...Sagan’s NFU argument, Timothy Fischer , in a U.S. Army War College study from 2012, countered that the United States should retain a policy of possible...nuclear response to WMD because of the important role of ambiguity in national security policy flexibility and deterrence. Fischer recommended that the

Introduction of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and preparatory activities for its entry into force

Energy Technology Data Exchange (ETDEWEB)

Tani, Hiroshi [Japan Atomic Energy Research Inst., Mutsu Establishment, Mutsu, Aomori (Japan)

2001-03-01

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is a very important treaty, not only for Japan but also for the world, because it prohibits any nuclear weapon test explosion or any other nuclear explosion anywhere in the world. The treaty however will not enter into force until it has been signed and ratified by all the 44 states listed in Annex 2 to the treaty. Many efforts to facilitate the treaty's early entry into force are being done by many countries and many international organizations. As one of result of these efforts, a Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization had be established at a meeting of State Signatories on 19 November 1996, and the Commission started activities to establish global verification regime of the treaty and to prepare for its entry into force. Under the CTBT activities, the Japan Atomic Energy Research Institute (JAERI) is expected to play an important role as supporter for the Japanese Government, especially in a field of an International Monitoring System (IMS). However, there is no appropriate guide book on the CTBT for JAERI staff at present. This report provides some introduction of the CTBT regime and preparatory activities for its entry into force. Only open source information is used for making the report. If anyone need more detail information, it should be asked to contact competent authorities. (author)

Probing the compressibility of tumor cell nuclei by combined atomic force-confocal microscopy

Science.gov (United States)

Krause, Marina; te Riet, Joost; Wolf, Katarina

2013-12-01

The cell nucleus is the largest and stiffest organelle rendering it the limiting compartment during migration of invasive tumor cells through dense connective tissue. We here describe a combined atomic force microscopy (AFM)-confocal microscopy approach for measurement of bulk nuclear stiffness together with simultaneous visualization of the cantilever-nucleus contact and the fate of the cell. Using cantilevers functionalized with either tips or beads and spring constants ranging from 0.06-10 N m-1, force-deformation curves were generated from nuclear positions of adherent HT1080 fibrosarcoma cell populations at unchallenged integrity, and a nuclear stiffness range of 0.2 to 2.5 kPa was identified depending on cantilever type and the use of extended fitting models. Chromatin-decondensating agent trichostatin A (TSA) induced nuclear softening of up to 50%, demonstrating the feasibility of our approach. Finally, using a stiff bead-functionalized cantilever pushing at maximal system-intrinsic force, the nucleus was deformed to 20% of its original height which after TSA treatment reduced further to 5% remaining height confirming chromatin organization as an important determinant of nuclear stiffness. Thus, combined AFM-confocal microscopy is a feasible approach to study nuclear compressibility to complement concepts of limiting nuclear deformation in cancer cell invasion and other biological processes.

Long-range goal setting in the nuclear utility industry

International Nuclear Information System (INIS)

Beard, P.M.

1986-01-01

The Institute of Nuclear Power Operation's (INPO's) programs support the industry's efforts to improve performance in nuclear plant safety and reliability. The success of these programs can best be measured by the progress of the industry. As utilities focused their attention on nuclear plant performance, the Institute's goal was to make sure its programs and activities provided the best possible support for these efforts. INPO continues to coordinate an industry-wide plant performance indicator program to assist member utilities in assessing station performance. Closely related to this effort is the nuclear industry's establishment of long-range plant performance goals. The US nuclear utility industry currently sends INPO quarterly data on 28 key performance indicators. INPO analyzes these data and provides periodic reports to its members and participants. Selected highlights of INPO's Performance Indicators for the US Nuclear Utility, dated June 1986, are discussed. Throughout 1985, INPO interacted with members, participants, and three external ad hoc review groups to refine the overall performance indicators and to develop background for each unit. By April 1986, each utility had developed long-term goals for each unit. By April 1986, each utility had developed long-term goals for most of the overall indicators. These goals represent a commitment to achievement of excellence when applied to the day-to-day conduct of plant operations, and provide a framework for action

Nuclear medicine methods in the assessment of acupuncture effects: a short review

International Nuclear Information System (INIS)

Souza, Deise Elisabete; Rebello, Bernardo Machado; Agostinho, Raquel Terra; Silva Filho, Reginaldo de Carvalho; Bernardo-Filho, Mario

2007-01-01

The mechanisms of acupuncture are poorly understood. In consequence, numerous investigators have conducted clinical trials to test the efficacy of acupuncture in various conditions. We have used PubMed database system to evaluate the number of publications in acupuncture and nuclear medicine procedures in the period from 1964 to 2007, using the keywords: 'nuclear medicine and acupuncture', 'SPECT and acupuncture, 'PET and acupuncture', 'scintigraphy and acupuncture, 'radionuclide and acupuncture', 'radiopharmaceutical and acupuncture', 'radioisotope and acupuncture' and 99m Tc and acupuncture'. Some papers published in English language were selected and a short review is presented The analysis of the number of publications shows that when a method is well accepted by the scientific community, as the methods used in nuclear medicine, the interest in the development of research increases. Moreover, important findings are presented when the nuclear medicine image is used to evaluate the effect of the acupuncture. (author)

Decreased long- and short-range functional connectivity at rest in drug-naive major depressive disorder.

Science.gov (United States)

Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Zhang, Zhikun; Yu, Miaoyu; Xue, Zhimin; Zhao, Jingping

2016-08-01

Abnormal functional connectivity has been observed in major depressive disorder. Anatomical distance may affect functional connectivity in patients with major depressive disorder. However, whether and how anatomical distance affects functional connectivity at rest remains unclear in drug-naive patients with major depressive disorder. Forty-four patients with major depressive disorder, as well as 44 age-, sex- and education-matched healthy controls, underwent resting-state functional magnetic resonance imaging scanning. Regional functional connectivity strength was calculated for each voxel in the whole brain, which was further divided into short- and long-range functional connectivity strength. The patients showed decreased long-range positive functional connectivity strength in the right inferior parietal lobule, as well as decreased short-range positive functional connectivity strength in the right insula and right superior temporal gyrus relative to those of the controls. No significant correlations existed between abnormal functional connectivity strength and the clinical variables of the patients. The findings revealed that anatomical distance decreases long- and short-range functional connectivity strength in patients with major depressive disorder, which may underlie the neurobiology of major depressive disorder. © The Royal Australian and New Zealand College of Psychiatrists 2015.

Acceptance criteria for determining armed response force size at nuclear power plants

International Nuclear Information System (INIS)

1983-02-01

This guidance document contains acceptance criteria to be used in the NRC license review process. It consists of a scored worksheet and guidelines for interpreting the worksheet score that can be used in determining the adequacy of the armed response force size at a nuclear power reactor facility

Structure of the short-range atomic order of WO3 amorphous films

International Nuclear Information System (INIS)

Olevskij, S.S.; Sergeev, M.S.; Tolstikhina, A.L.; Avilov, A.S.; Shkornyakov, S.M.; Semiletov, S.A.

1984-01-01

To study the causes of electrochromism manifestation in thin tungsten oxide films, the structure of WO 3 amorphous films has been investigated. The films were obtained by three different methods: by W(CO) 6 tungsten carbonyl pyrolysis, by high-frequency ion-plasma sputtering of a target prepared by WO 3 powder sintering, and by WO 3 powder thermal evaporation. Monocrystalline wafers of silicon and sodium chloride were used as substrates. The structure of short-range order in WO 3 amorphous films varies versus, the method of preparation in compliance with the type of polyhedral elements, (WO 6 , WO 5 ) and with the character of their packing (contacts via edges or vertices). Manifestation of electroc ro mism in WO 3 films prepared by varions methods and having different structure of short-range order is supposed to be realized through various mechanisms. One cannot exclude a potential simultaneous effect of the two coloration mechanisms

Does an electronic continuum correction improve effective short-range ion-ion interactions in aqueous solution?

Science.gov (United States)

Bruce, Ellen E.; van der Vegt, Nico F. A.

2018-06-01

Non-polarizable force fields for hydrated ions not always accurately describe short-range ion-ion interactions, frequently leading to artificial ion clustering in bulk aqueous solutions. This can be avoided by adjusting the nonbonded anion-cation or cation-water Lennard-Jones parameters. This approach has been successfully applied to different systems, but the parameterization is demanding owing to the necessity of separate investigations of each ion pair. Alternatively, polarization effects may effectively be accounted for using the electronic continuum correction (ECC) of Leontyev et al. [J. Chem. Phys. 119, 8024 (2003)], which involves scaling the ionic charges with the inverse square-root of the water high-frequency dielectric permittivity. ECC has proven to perform well for monovalent salts as well as for divalent salts in water. Its performance, however, for multivalent salts with higher valency remains unexplored. The present work illustrates the applicability of the ECC model to trivalent K3PO4 and divalent K2HPO4 in water. We demonstrate that the ECC models, without additional tuning of force field parameters, provide an accurate description of water-mediated interactions between salt ions. This results in predictions of the osmotic coefficients of aqueous K3PO4 and K2HPO4 solutions in good agreement with experimental data. Analysis of ion pairing thermodynamics in terms of contact ion pair (CIP), solvent-separated ion pair, and double solvent-separated ion pair contributions shows that potassium-phosphate CIP formation is stronger with trivalent than with divalent phosphate ions.

33 CFR 334.640 - Gulf of Mexico south of Apalachee Bay, Fla.; Air Force rocket firing range.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Gulf of Mexico south of Apalachee Bay, Fla.; Air Force rocket firing range. 334.640 Section 334.640 Navigation and Navigable Waters... REGULATIONS § 334.640 Gulf of Mexico south of Apalachee Bay, Fla.; Air Force rocket firing range. (a) The...

Design of a self-aligned, wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with 10 nm magnetic force microscope resolution

Energy Technology Data Exchange (ETDEWEB)

Karcı, Özgür [NanoMagnetics Instruments Ltd., Hacettepe - İvedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Dede, Münir [NanoMagnetics Instruments Ltd., Hacettepe - İvedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Oral, Ahmet, E-mail: orahmet@metu.edu.tr [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)

2014-10-01

We describe the design of a wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ~12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.

Design of a self-aligned, wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with 10 nm magnetic force microscope resolution

International Nuclear Information System (INIS)

Karcı, Özgür; Dede, Münir; Oral, Ahmet

2014-01-01

We describe the design of a wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ∼12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system

Forced cooling of a nuclear waste repository mine drift - a scoping analysis

Energy Technology Data Exchange (ETDEWEB)

Boyd, R D [Sandia National Labs., Albuquerque, NM (USA)

1982-12-01

Nuclear waste repositories, with decay heat generation beneath the mine drift floors, are force-cooled with air so that re-entrance is possible many years after the waste has been buried. A numerical model has been developed which uses heat transfer coefficients as input. It has been demonstrated that mixed (forced and free) convective and surface roughness effects are significant and must be included in future experiments if reliable predictions are to be made of the time required to cool the repository. For example, when repository mine drifts in volcanic tuff are force-cooled, with forced convection being the only energy transport mechanism, it takes approx.= 0.1 year to cool the mine surface to a safe temperature. However, when mixed convection is the primary transport mechanism it takes approx.= 1.0 year to cool the mine. In addition to mixed convection, other effects are delineated.

Polyamorphism and substructure of short-range order in amorphous boron films

International Nuclear Information System (INIS)

Palatnik, L.S.; Nechitajlo, A.A.; Koz'ma, A.A.

1981-01-01

The structure and substructure of boron amorphous films are studied in detail. Amorphous condensate of Bsup(a) boron is built of the same (but only disorientedly located) 12 B icosahedrons as boron crystalline modifications: B 105 -equilibrium β-rhombic, metastable: B 50 -tetragonal, B 12 -α-rhombohedral Coordination number for Bsup(a) (Z 1 =6.4) is lower than in B 105 (Z 1 =6.6) but higher than in B 50 modification (Z 1 =6.1). In crystalline modifications B 105 , B 50 , B 12 coordination numbers ω in first coordination spheres of icosahedrons are equal to ν 105 =6+4.6=10.6; ν 50 =10+3=14; ν 12 =6 respectively. Both amorphous modifications of boron Bsub(1)sup(a) and Bsub(15)sup(a) are analogs to B 50 in respect of the short-range order of icosahedron location. The difference between them is in ''substructure'' of short-range order: part of boron atoms (approximately 12%) do not occupy the vertices (so that vacancies appear) and enter the emptinesses between icosahedrons. In other words, the structure B 50 is the model basis of both amorphous phases [ru

Aerodynamic Jump: A Short Range View for Long Rod Projectiles

Directory of Open Access Journals (Sweden)

Mark Bundy

2001-01-01

Full Text Available It is shown that aerodynamic jump for a nonspinning kinetic energy penetrator is not – as conventional definitions may infer – a discontinuous change in the direction of motion at the origin of free flight, nor is it the converse, a cumulative redirection over a domain of infinite extent. Rather, with the aid of an alternative kinematical definition, it is shown that aerodynamic jump for such a projectile is a localized redirection of the center-of-gravity motion, caused by the force of lift due to yaw over the relatively short region from entry into free flight until the yaw reaches its first maximum. A rigorous proof of this statement is provided, but the primary objective of this paper is to provide answers to the questions: what is aerodynamic jump, what does it mean, and what aspects of the flight trajectory does it refer to, or account for.

Description of nuclear structure and cross sections for nucleon-nucleus scattering on the basis of effective Skyrme forces

International Nuclear Information System (INIS)

Kuprikov, V. I.; Pilipenko, V. V.; Soznik, A. P.; Tarasov, V. N.; Shlyakhov, N. A.

2009-01-01

The possibility of constructing such new versions of effective nucleon-nucleon forces that would make it possible to describe simultaneously the cross sections for nucleon-nucleus scattering and quantities characterizing nuclear matter and the structure of finite even-even nuclei is investigated on the basis of a microscopic nucleon-nucleus optical potential that is calculated by using effective Skyrme interaction. A procedure for optimizing the parameters of Skyrme forces by employing fits to specific angular distributions for neutron-nucleus scattering and by simultaneously testing the features of nuclear matter, the binding energy of the target nucleus, and its proton root-mean-square radius is proposed. A number of versions of modified Skyrme forces that ensure a reasonable description of both nucleon-nucleus scattering and the properties of nuclear structure are found on the basis of this procedure.

The short life radionuclides in meat after the nuclear accident in Chernobyl

International Nuclear Information System (INIS)

Smelcerovic, M.; Popovic, D.; Djuric, G.

1992-01-01

The paper presents the results of identification and short life radionuclides (I-131, Te (I)-132, Cs-136, Ce-141, 144, Ru-103, 106, Ba(La)-140, Zr-95, Nb-95, Mo-99, Sb-125) mass activities evaluation in meat (lamb, rabbit, game) after the nuclear accident in Chernobyl in 1986. (author)

Chapter 4: Pulsating Wave Loads Section 4.3: 3D Effects Force Reduction of Short-Crested Non-Breaking Waves on Caissons

DEFF Research Database (Denmark)

Burcharth, Hans F.; Liu, Zhou

1999-01-01

The effect of wave short-crestedness on the horizontal wave force on a caisson is twofold. The one is the force reduction due to the reduction of point pressure on the caisson, named point-pressure reduction. The other is the force reduction due to the fact that the peak pressures do not occur si...

Effects of nonmagnetic interparticle forces on magnetorheological fluids

International Nuclear Information System (INIS)

Klingenberg, D J; Olk, C H; Golden, M A; Ulicny, J C

2010-01-01

Effects of nonmagnetic interparticle forces on the on- and off-state behavior of magnetorheological fluids are investigated experimentally and with particle-level simulations. Suspensions of iron particles in an aliphatic oil are modified by surface-active species. The modifications significantly alter the off-state properties, but have little impact on the field-induced stresses. Simulations show similar behavior. Off-state rheological properties are strongly influenced by van der Waals forces and modifications of the short-range repulsive forces. Field-induced stresses are less sensitive to the nonmagnetic forces.

Effects of nonmagnetic interparticle forces on magnetorheological fluids

International Nuclear Information System (INIS)

Klingenberg, D J; Olk, C K; Golden, M A; Ulicny, J C

2009-01-01

Effects of nonmagnetic interparticle forces on the on- and off-state behavior of MR fluids are investigated experimentally and with particle-level simulations. Suspensions of iron particles in an aliphatic oil are modified by surface-active species. The modifications significantly alter the off-state properties, but have little impact on the field-induced stresses. Simulations show similar behavior. Off-state rheological properties are strongly influenced by van der Waals forces and modifications of the short-range repulsive forces. Field-induced stresses are less sensitive to the nonmagnetic forces.

Answers to questions posed by the Michigan Governor's Nuclear Waste Disposal Task Force

International Nuclear Information System (INIS)

1976-01-01

A general presentation of the National Waste Terminal Storage (NWTS) Program was given on July 26, 1976, to the Michigan Environmental Review Board and the Michigan Governor's Nuclear Waste Disposal Task Force. Following the presentation, Dr. William G. Taylor, Chairman of the Task Force, provided ERDA with a listing of questions which pertained to the NWTS program and ERDA/OWI's interest in northeast Michigan. This document contains copies of the information which was provided to Dr. Taylor in response to his inquiry

Short range order in FeCo-X alloys

International Nuclear Information System (INIS)

Fultz, B.

1988-01-01

Moessbauer spectrometry was used to study the kinetics of chemical ordering in FeCo and in FeCo alloyed with ternary solutes. With respect to the binary FeCo alloy, the kinetics of B2 ordering were slowed when 2% of 4d- or 5d-series ternary solute atoms were present, but 3p- and 3d-series ternary solutes had little effect on ordering kinetics. The relaxation of order around the ternary solute atoms could be discerned in Moessbauer spectra, and it seems that the development of B2 short range order is influenced by structural relaxations around the ternary solute atoms. Different thermal treatments were shown to cause different relaxations of and correlations, suggesting that Moessbauer spectrometry can be used to identify different kinetic paths of ordering in ternary alloys. (orig.)

Fluid–fluid coexistence in colloidal systems with short-ranged strongly directional attraction

NARCIS (Netherlands)

Kern, N.; Frenkel, D.

2003-01-01

We present a systematic numerical study of the phase behavior of square-well fluids with a "patchy" short-ranged attraction. In particular, we study the effect of the size and number of attractive patches on the fluid–fluid coexistence. The model that we use is a generalization of the hard sphere

University of New Mexico short course in nuclear criticality safety: Training for new NCS [nuclear criticality safety] specialists

International Nuclear Information System (INIS)

Busch, R.D.

1990-01-01

Since 1973, the University of New Mexico (UNM) has given ten short courses in nuclear criticality safety (NCS). Generally, thee have been given every other year, although in 1989 it was decided to offer the course on an annual basis. This decision was primarily based on the large demand for NCS specialists and a large turnover rate in the industry. The purpose of the course is to provide a 1-week overview of NCS. The typical student has been involved in NCS for <1 yr, although it many cases they have been associated with the nuclear industry in other capacities for many years. The short course is conducted at several levels. Carefully prepared lectures provide the information framework for selected topics. The following topics are covered in the course: basic reactor theory, criticality accidents and consequences, hand calculations, administration of a criticality safety program, regulators and their processes, computer methods and applications, experimental methods and correlations, overview of some process operations, and transportation and storage issues in NCS

Towards highest peak intensities for ultra-short MeV-range ion bunches

OpenAIRE

Simon Busold; Dennis Schumacher; Christian Brabetz; Diana Jahn; Florian Kroll; Oliver Deppert; Ulrich Schramm; Thomas E. Cowan; Abel Blažević; Vincent Bagnoud; Markus Roth

2015-01-01

A laser-driven, multi-MeV-range ion beamline has been installed at the GSI Helmholtz center for heavy ion research. The high-power laser PHELIX drives the very short (picosecond) ion acceleration on ?m scale, with energies ranging up to 28.4?MeV for protons in a continuous spectrum. The necessary beam shaping behind the source is accomplished by applying magnetic ion lenses like solenoids and quadrupoles and a radiofrequency cavity. Based on the unique beam properties from the laser-driven so...

Nuclear medicine methods in the assessment of acupuncture effects: a short review

Energy Technology Data Exchange (ETDEWEB)

Souza, Deise Elisabete; Rebello, Bernardo Machado; Agostinho, Raquel Terra [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Lab. de Radiofarmacia Experimental; Academia Brasileira de Arte e Ciencia Oriental, Rio de Janeiro, RJ (Brazil); E-mail: deise_desouza@yahoo.com.br; Silva Filho, Reginaldo de Carvalho [Escola Brasileira de Medicina Chinesa, Sao Paulo, SP (Brazil). Centro Avancado de Pesquisas em Ciencias Orientais; Bastos, Sohaku R.C. [Academia Brasileira de Arte e Ciencia Oriental, Rio de Janeiro, RJ (Brazil); Bernardo-Filho, Mario [Instituto Nacional de Cancer (INCa), Rio de Janeiro, RJ (Brazil). Centro de Pesquisa Basica

2007-09-15

The mechanisms of acupuncture are poorly understood. In consequence, numerous investigators have conducted clinical trials to test the efficacy of acupuncture in various conditions. We have used PubMed database system to evaluate the number of publications in acupuncture and nuclear medicine procedures in the period from 1964 to 2007, using the keywords: 'nuclear medicine and acupuncture', 'SPECT and acupuncture, 'PET and acupuncture', 'scintigraphy and acupuncture, 'radionuclide and acupuncture', 'radiopharmaceutical and acupuncture', 'radioisotope and acupuncture' and {sup 99m}Tc and acupuncture'. Some papers published in English language were selected and a short review is presented The analysis of the number of publications shows that when a method is well accepted by the scientific community, as the methods used in nuclear medicine, the interest in the development of research increases. Moreover, important findings are presented when the nuclear medicine image is used to evaluate the effect of the acupuncture. (author)

An overview of the activities of the OECD/NEA Task Force on adapting computer codes in nuclear applications to parallel architectures

Energy Technology Data Exchange (ETDEWEB)

Kirk, B.L. [Oak Ridge National Lab., TN (United States); Sartori, E. [OCDE/OECD NEA Data Bank, Issy-les-Moulineaux (France); Viedma, L.G. de [Consejo de Seguridad Nuclear, Madrid (Spain)

1997-06-01

Subsequent to the introduction of High Performance Computing in the developed countries, the Organization for Economic Cooperation and Development/Nuclear Energy Agency (OECD/NEA) created the Task Force on Adapting Computer Codes in Nuclear Applications to Parallel Architectures (under the guidance of the Nuclear Science Committee`s Working Party on Advanced Computing) to study the growth area in supercomputing and its applicability to the nuclear community`s computer codes. The result has been four years of investigation for the Task Force in different subject fields - deterministic and Monte Carlo radiation transport, computational mechanics and fluid dynamics, nuclear safety, atmospheric models and waste management.

An overview of the activities of the OECD/NEA Task Force on adapting computer codes in nuclear applications to parallel architectures

International Nuclear Information System (INIS)

Kirk, B.L.; Sartori, E.; Viedma, L.G. de

1997-01-01

Subsequent to the introduction of High Performance Computing in the developed countries, the Organization for Economic Cooperation and Development/Nuclear Energy Agency (OECD/NEA) created the Task Force on Adapting Computer Codes in Nuclear Applications to Parallel Architectures (under the guidance of the Nuclear Science Committee's Working Party on Advanced Computing) to study the growth area in supercomputing and its applicability to the nuclear community's computer codes. The result has been four years of investigation for the Task Force in different subject fields - deterministic and Monte Carlo radiation transport, computational mechanics and fluid dynamics, nuclear safety, atmospheric models and waste management

Towards highest peak intensities for ultra-short MeV-range ion bunches

Science.gov (United States)

Busold, Simon; Schumacher, Dennis; Brabetz, Christian; Jahn, Diana; Kroll, Florian; Deppert, Oliver; Schramm, Ulrich; Cowan, Thomas E.; Blažević, Abel; Bagnoud, Vincent; Roth, Markus

2015-01-01

A laser-driven, multi-MeV-range ion beamline has been installed at the GSI Helmholtz center for heavy ion research. The high-power laser PHELIX drives the very short (picosecond) ion acceleration on μm scale, with energies ranging up to 28.4 MeV for protons in a continuous spectrum. The necessary beam shaping behind the source is accomplished by applying magnetic ion lenses like solenoids and quadrupoles and a radiofrequency cavity. Based on the unique beam properties from the laser-driven source, high-current single bunches could be produced and characterized in a recent experiment: At a central energy of 7.8 MeV, up to 5 × 108 protons could be re-focused in time to a FWHM bunch length of τ = (462 ± 40) ps via phase focusing. The bunches show a moderate energy spread between 10% and 15% (ΔE/E0 at FWHM) and are available at 6 m distance to the source und thus separated from the harsh laser-matter interaction environment. These successful experiments represent the basis for developing novel laser-driven ion beamlines and accessing highest peak intensities for ultra-short MeV-range ion bunches. PMID:26212024

Towards highest peak intensities for ultra-short MeV-range ion bunches

Science.gov (United States)

Busold, Simon; Schumacher, Dennis; Brabetz, Christian; Jahn, Diana; Kroll, Florian; Deppert, Oliver; Schramm, Ulrich; Cowan, Thomas E.; Blažević, Abel; Bagnoud, Vincent; Roth, Markus

2015-07-01

A laser-driven, multi-MeV-range ion beamline has been installed at the GSI Helmholtz center for heavy ion research. The high-power laser PHELIX drives the very short (picosecond) ion acceleration on μm scale, with energies ranging up to 28.4 MeV for protons in a continuous spectrum. The necessary beam shaping behind the source is accomplished by applying magnetic ion lenses like solenoids and quadrupoles and a radiofrequency cavity. Based on the unique beam properties from the laser-driven source, high-current single bunches could be produced and characterized in a recent experiment: At a central energy of 7.8 MeV, up to 5 × 108 protons could be re-focused in time to a FWHM bunch length of τ = (462 ± 40) ps via phase focusing. The bunches show a moderate energy spread between 10% and 15% (ΔE/E0 at FWHM) and are available at 6 m distance to the source und thus separated from the harsh laser-matter interaction environment. These successful experiments represent the basis for developing novel laser-driven ion beamlines and accessing highest peak intensities for ultra-short MeV-range ion bunches.

Measurement based scenario analysis of short-range distribution system planning

DEFF Research Database (Denmark)

Chen, Peiyuan; Bak-Jensen, Birgitte; Chen, Zhe

2009-01-01

This paper focuses on short-range distribution system planning using a probabilistic approach. Empirical probabilistic distributions of load demand and distributed generations are derived from the historical measurement data and incorporated into the system planning. Simulations with various...... feasible scenarios are performed based on a local distribution system at Støvring in Denmark. Simulation results provide more accurate and insightful information for the decision-maker when using the probabilistic analysis than using the worst-case analysis, so that a better planning can be achieved....

Using atom interferometry to search for new forces

International Nuclear Information System (INIS)

Wacker, Jay G.

2010-01-01

Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10 2 and near-future advances may be able to rewrite the limits for forces with ranges from 1 mm to 100 m.

Using Atom Interferometry to Search for New Forces

International Nuclear Information System (INIS)

Wacker, Jay G.

2009-01-01

Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10 2 and near-future advances will be able to rewrite the limits for forces with ranges from 100 (micro)m to 1km.

Impact of preindustrial to present-day changes in short-lived pollutant emissions on atmospheric composition and climate forcing

Science.gov (United States)

Naik, Vaishali; Horowitz, Larry W.; Fiore, Arlene M.; Ginoux, Paul; Mao, Jingqiu; Aghedo, Adetutu M.; Levy, Hiram

2013-07-01

We describe and evaluate atmospheric chemistry in the newly developed Geophysical Fluid Dynamics Laboratory chemistry-climate model (GFDL AM3) and apply it to investigate the net impact of preindustrial (PI) to present (PD) changes in short-lived pollutant emissions (ozone precursors, sulfur dioxide, and carbonaceous aerosols) and methane concentration on atmospheric composition and climate forcing. The inclusion of online troposphere-stratosphere interactions, gas-aerosol chemistry, and aerosol-cloud interactions (including direct and indirect aerosol radiative effects) in AM3 enables a more complete representation of interactions among short-lived species, and thus their net climate impact, than was considered in previous climate assessments. The base AM3 simulation, driven with observed sea surface temperature (SST) and sea ice cover (SIC) over the period 1981-2007, generally reproduces the observed mean magnitude, spatial distribution, and seasonal cycle of tropospheric ozone and carbon monoxide. The global mean aerosol optical depth in our base simulation is within 5% of satellite measurements over the 1982-2006 time period. We conduct a pair of simulations in which only the short-lived pollutant emissions and methane concentrations are changed from PI (1860) to PD (2000) levels (i.e., SST, SIC, greenhouse gases, and ozone-depleting substances are held at PD levels). From the PI to PD, we find that changes in short-lived pollutant emissions and methane have caused the tropospheric ozone burden to increase by 39% and the global burdens of sulfate, black carbon, and organic carbon to increase by factors of 3, 2.4, and 1.4, respectively. Tropospheric hydroxyl concentration decreases by 7%, showing that increases in OH sinks (methane, carbon monoxide, nonmethane volatile organic compounds, and sulfur dioxide) dominate over sources (ozone and nitrogen oxides) in the model. Combined changes in tropospheric ozone and aerosols cause a net negative top

Far from the intermediate nuclear field

International Nuclear Information System (INIS)

Dietrich, K.; Wagner, G.J.; Gregoire, C.; Campi, X.; Silvestre-Brac, B.; Platchkov, S.; Mayer, B.; Abgrall, Y.; Bohigas, O.; Grange, P.; Signarbieux, C.

1988-01-01

Pairing correlations in nuclear physics; the BCS state and quasi-particles; the layer model; collision effects on nuclear dynamics; the theory of cluster formation (application to nucleus fragmentation); short range correlations (few-particle systems); deuterium electron scattering; dibaryonic resonances; traditional and exotic hadron probes of nuclear structure; spectral fluctuations and chaotic motion; corrections to the intermediate nuclear field (nonrelativistic and other effects); and heavy nuclei splitting and nuclear superfluidity are introduced [fr

Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.

Science.gov (United States)

Zhang, Songning; Clowers, Kurt G; Powell, Douglas

2006-12-01

Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

Status of the dedicated short-range communications technology and applications : report to Congress.

Science.gov (United States)

2015-07-01

This report responds to a Congressional request for an assessment of the 5.9 Gigahertz (GHz) Dedicated Short Range : Communications (DSRC) in accordance with the requirements provided by Congress in the Moving Ahead for Progress in the : 21st Century...

Short range order of Mg-Cd-alloys during the transition from the solid to the molten state

International Nuclear Information System (INIS)

Boos, A.; Steeb, S.

1977-01-01

Recently a method was published for the determination of short range order parameters in binary melts and also a method for the determination of the concentration of different structures which form such a melt. These methods are used in the present work to evaluate the atomic structure of Mg-Cd-melts and to reval the changes in short range order during the melting process. (orig.) [de

Study of the parity violation in nuclei - Circular polarization of photons emitted in a nuclear transition

International Nuclear Information System (INIS)

Desplanques, Bertrand.

1975-01-01

Many experiments have shown parity violation in nuclear forces and a theoretical interpretation of these results should give some information on the weak interaction. The present work has to do with the calculation of the circular polarization of photons emitted in the transitions 5/2 + →7/2 + in 181 Ta and 9/2 - →7/2 + in 175 Lu. This calculation has been done by employing a good description of the final and initial states and in particular by including the effects of the short and long range correlations. The results so obtained differ somewhat from those obtained previously with a simpler nuclear model and seem to favor weak interaction models with a large ΔT=1 component [fr

Dangerous dream: Nuclear power. With an attached short dictionary of terms in nuclear energy. Der gefaehrliche Traum: Atomkraft. Mit kleinem Lexikon der Atom-Energie

Energy Technology Data Exchange (ETDEWEB)

Paul, R

1986-01-01

After Chernobyl: Necessary basic knowledge and information, data on safety hazards and risks, sketches of all German nuclear power plants and brief accounts of incidents reported so far, consequences of the Chernobyl and Harrisburg accidents for man and the environment, emergency control plans. With an attached short dictionary of terms in nuclear energy.

Influence of short range ordering and clustering on transport properties

International Nuclear Information System (INIS)

Vigier, G.; Pelletier, J.M.

1982-01-01

The influence of short range ordering and clustering phenomena on the electrical resistivity p and the thermopower S is investigated both theoretically and experimentally. According to the considered alloys either increases or decreases of transport properties may be observed when deviations from a random distribution of solute atoms occur. These observations are explained with a model based on free electrons and Born approximations the importance of the potential choice is underlined; two kinds of description of the structure factor are investigated. A good semiquantitative agreement is obtained between computed results and experimental observations

OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

DEFF Research Database (Denmark)

Medhin, Ashenafi Kiros

This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra...

Highly accurate nuclear and electronic stopping cross sections derived using Monte Carlo simulations to reproduce measured range data

Science.gov (United States)

Wittmaack, Klaus; Mutzke, Andreas

2017-03-01

We have examined and confirmed the previously unexplored concept of using Monte Carlo calculations in combination with measured projected ranges of ions implanted in solids to derive a quantitative description of nuclear interaction and electronic stopping. The study involved 98 ranges of 11B in Si between 1 keV and 8 MeV, contained in 12 sets of 10 different groups. Systematic errors by up to ±8% were removed to establish a refined data base with 93 ranges featuring only statistical uncertainties (±1.8%). The Monte Carlo calculations could be set up to reproduce the refined ranges with a mean ratio 1.002 ± 1.7%. The input parameters required for this very high level of agreement are as follows. Nuclear interaction is best described by the Kr-C potential, but in obligatory combination with the Lindhard-Scharff (LS) screening length. Up to 300 keV, the electronic stopping cross section is proportional to the projectile velocity, Se = kSe,LS, with k = 1.46 ± 0.01. At higher energies, Se falls progressively short of kSe,LS. Around the Bragg peak, i.e., between 0.8 and 10 MeV, Se is modeled by an adjustable function serving to tailor the peak shape properly. Calculated and measured isotope effects for ranges of 10B and 11B in Si agree within the experimental uncertainty (±0.25%). The range-based Se,R(E) reported here predicts the scarce experimental data derived from the energy loss in projectile transmission through thin Si foils to within 2% or better. By contrast, Se(E) data of available stopping power tables exhibit deviations from Se,R(E) between -40% and +14%.

Short-range solar radiation forecasts over Sweden

Directory of Open Access Journals (Sweden)

T. Landelius

2018-04-01

Full Text Available In this article the performance for short-range solar radiation forecasts by the global deterministic and ensemble models from the European Centre for Medium-Range Weather Forecasts (ECMWF is compared with an ensemble of the regional mesoscale model HARMONIE-AROME used by the national meteorological services in Sweden, Norway and Finland. Note however that only the control members and the ensemble means are included in the comparison. The models resolution differs considerably with 18 km for the ECMWF ensemble, 9 km for the ECMWF deterministic model, and 2.5 km for the HARMONIE-AROME ensemble.The models share the same radiation code. It turns out that they all underestimate systematically the Direct Normal Irradiance (DNI for clear-sky conditions. Except for this shortcoming, the HARMONIE-AROME ensemble model shows the best agreement with the distribution of observed Global Horizontal Irradiance (GHI and DNI values. During mid-day the HARMONIE-AROME ensemble mean performs best. The control member of the HARMONIE-AROME ensemble also scores better than the global deterministic ECMWF model. This is an interesting result since mesoscale models have so far not shown good results when compared to the ECMWF models.Three days with clear, mixed and cloudy skies are used to illustrate the possible added value of a probabilistic forecast. It is shown that in these cases the mesoscale ensemble could provide decision support to a grid operator in terms of forecasts of both the amount of solar power and its probabilities.

Interplay of long-range and short-range Coulomb interactions in an Anderson-Mott insulator

Science.gov (United States)

Baćani, Mirko; Novak, Mario; Orbanić, Filip; Prša, Krunoslav; Kokanović, Ivan; Babić, Dinko

2017-07-01

In this paper, we tackle the complexity of coexisting disorder and Coulomb electron-electron interactions (CEEIs) in solids by addressing a strongly disordered system with intricate CEEIs and a screening that changes both with charge carrier doping level Q and temperature T . We report on an experimental comparative study of the T dependencies of the electrical conductivity σ and magnetic susceptibility χ of polyaniline pellets doped with dodecylbenzenesulfonic acid over a wide range. This material is special within the class of doped polyaniline by exhibiting in the electronic transport a crossover between a low-T variable range hopping (VRH) and a high-T nearest-neighbor hopping (NNH) well below room temperature. Moreover, there is evidence of a soft Coulomb gap ΔC in the disorder band, which implies the existence of a long-range CEEI. Simultaneously, there is an onsite CEEI manifested as a Hubbard gap U and originating in the electronic structure of doped polyaniline, which consists of localized electron states with dynamically varying occupancy. Therefore, our samples represent an Anderson-Mott insulator in which long-range and short-range CEEIs coexist. The main result of the study is the presence of a crossover between low- and high-T regimes not only in σ (T ) but also in χ (T ) , the crossover temperature T* being essentially the same for both observables over the entire doping range. The relatively large electron localization length along the polymer chains results in U being small, between 12 and 20 meV for the high and low Q , respectively. Therefore, the thermal energy at T* is sufficiently large to lead to an effective closing of the Hubbard gap and the consequent appearance of NNH in the electronic transport within the disorder band. ΔC is considerably larger than U , decreasing from 190 to 30 meV as Q increases, and plays the role of an activation energy in the NNH.

A study of existing experimental data and validation process for evaluated high energy nuclear data. Report of task force on integral test for JENDL High Energy File in Japanese Nuclear Data Committee

International Nuclear Information System (INIS)

Oyama, Yukio; Baba, Mamoru; Watanabe, Yukinobu

1998-11-01

JENDL High Energy File (JENDL-HE) is being produced by Japanese Nuclear Data Committee (JNDC) to provide common fundamental nuclear data in the intermediate energy region for many applications concerning a basic research, an accelerator-driven nuclear waste transmutation, a fusion material study, and medical applications like the radiation therapy. The first version of JENDL-HE, which contains the evaluated nuclear data up to 50 MeV, is planned to release in 1998. However, a method of integral test with which we can validate the high-energy nuclear data file has not been established. The validation of evaluated nuclear data through the integral tests is necessary to promote utilization of JENDL-HE. JNDC set up a task force in 1997 to discuss the problems concerning the integral tests of JENDL-HE. The task force members have surveyed and studied the current status of the problems for a year to obtain a guideline for development of the high-energy nuclear database. This report summarizes the results of the survey and study done by the task force for JNDC. (author)

Impact Force Applied on the Spent Nuclear Fuel Disposal Canister that Accidentally Drops and Collides onto the Ground

International Nuclear Information System (INIS)

Kwon, Young Joo

2016-01-01

In this paper, a mathematical methodology was theoretically studied to obtain the impact force caused by the collision between rigid bodies. This theoretical methodology was applied to compute the impact force applied on the spent nuclear fuel disposal canister that accidentally drops and collides onto the ground. From this study, the impact force required to ensure a structurally safe canister design was theoretically formulated. The main content of the theoretical study concerns the rigid body kinematics and equation of motion during collision between two rigid bodies. On the basis of this study, a general impact theory to compute the impact force caused by the collision between two bodies was developed. This general impact theory was applied to theoretically formulate the approximate mathematical solution of the impact force that affects the spent nuclear fuel disposal canister that accidentally falls to the ground. Simultaneously, a numerical analysis was performed using the computer code to compute the numerical solution of the impact force, and the numerical result was compared with the approximate mathematical solution

Optimized molecular dynamics force fields applied to the helix-coil transition of polypeptides.

Science.gov (United States)

Best, Robert B; Hummer, Gerhard

2009-07-02

Obtaining the correct balance of secondary structure propensities is a central priority in protein force-field development. Given that current force fields differ significantly in their alpha-helical propensities, a correction to match experimental results would be highly desirable. We have determined simple backbone energy corrections for two force fields to reproduce the fraction of helix measured in short peptides at 300 K. As validation, we show that the optimized force fields produce results in excellent agreement with nuclear magnetic resonance experiments for folded proteins and short peptides not used in the optimization. However, despite the agreement at ambient conditions, the dependence of the helix content on temperature is too weak, a problem shared with other force fields. A fit of the Lifson-Roig helix-coil theory shows that both the enthalpy and entropy of helix formation are too small: the helix extension parameter w agrees well with experiment, but its entropic and enthalpic components are both only about half the respective experimental estimates. Our structural and thermodynamic analyses point toward the physical origins of these shortcomings in current force fields, and suggest ways to address them in future force-field development.

High-resolution and large dynamic range nanomechanical mapping in tapping-mode atomic force microscopy

International Nuclear Information System (INIS)

Sahin, Ozgur; Erina, Natalia

2008-01-01

High spatial resolution imaging of material properties is an important task for the continued development of nanomaterials and studies of biological systems. Time-varying interaction forces between the vibrating tip and the sample in a tapping-mode atomic force microscope contain detailed information about the elastic, adhesive, and dissipative response of the sample. We report real-time measurement and analysis of the time-varying tip-sample interaction forces with recently introduced torsional harmonic cantilevers. With these measurements, high-resolution maps of elastic modulus, adhesion force, energy dissipation, and topography are generated simultaneously in a single scan. With peak tapping forces as low as 0.6 nN, we demonstrate measurements on blended polymers and self-assembled molecular architectures with feature sizes at 1, 10, and 500 nm. We also observed an elastic modulus measurement range of four orders of magnitude (1 MPa to 10 GPa) for a single cantilever under identical feedback conditions, which can be particularly useful for analyzing heterogeneous samples with largely different material components.

Resistance to alveolar shape change limits range of force propagation in lung parenchyma.

Science.gov (United States)

Ma, Baoshun; Smith, Bradford J; Bates, Jason H T

2015-06-01

We have recently shown that if the lung parenchyma is modeled in 2 dimensions as a network of springs arranged in a pattern of repeating hexagonal cells, the distortional forces around a contracting airway propagate much further from the airway wall than classic continuum theory predicts. In the present study we tested the hypothesis that this occurs because of the negligible shear modulus of a hexagonal spring network. We simulated the narrowing of an airway embedded in a hexagonal network of elastic alveolar walls when the hexagonal cells of the network offered some resistance to a change in shape. We found that as the forces resisting shape change approach about 10% of the forces resisting length change of an individual spring the range of distortional force propagation in the spring network fell of rapidly as in an elastic continuum. We repeated these investigations in a 3-dimensional spring network composed of space-filling polyhedral cells and found similar results. This suggests that force propagation away from a point of local parenchymal distortion also falls off rapidly in real lung tissue. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly excited bound-state resonances of short-range inverse power-law potentials

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

2017-11-15

We study analytically the radial Schroedinger equation with long-range attractive potentials whose asymptotic behaviors are dominated by inverse power-law tails of the form V(r) = -β{sub n}r{sup -n} with n > 2. In particular, assuming that the effective radial potential is characterized by a short-range infinitely repulsive core of radius R, we derive a compact analytical formula for the threshold energy E{sub l}{sup max} = E{sub l}{sup max}(n, β{sub n}, R), which characterizes the most weakly bound-state resonance (the most excited energy level) of the quantum system. (orig.)

Multi-input wide dynamic range ADC system for use with nuclear detectors

Energy Technology Data Exchange (ETDEWEB)

Austin, R W [National Aeronautics and Space Administration, Huntsville, Ala. (USA). George C. Marshall Space Flight Center

1976-04-15

A wide dynamic range, eight input analog-to-digital converter system has been developed for use in nuclear experiments. The system consists of eight dual-range sample and hold modules, an eight input multiplexer, a ten-bit analog-to-digital converter, and the associated control logic.

Essential equivalence: the objectives and requirements of a stategic nuclear policy: a perspective on the evolution of US strategic nuclear policy, and an assessment of present and emerging US strategic policy and force stucture options

International Nuclear Information System (INIS)

Hughes, P.C.

1979-01-01

This study provides a discussion of the origins and evolution of US strategic nuclear policy, the objectives an requirements of US nuclear forces, and an assessment of present and emerging US stategic nuclear policy and force structure options. It identifies the distinctive phases of US strategic nuclear policy, the conditions of the military environments in which those policies were developed, the interaction of US-Soviet strategic force and arms control processes during these phases, and the domestic debates which have accompanied US strategic nuclear policy developments. In particular, the study focuses on the major contending views which continue to characterize the debate concerning US strategic nuclear policy. The study assesses the implications of the contending views represented in what is commonly referred to as the counterforce-countervalue debate, particularly as they relate to the perception of what constitutes a credible US deterrent posture, and the corresponding alternatives that these views bring with them for making US strategic nuclear policy and force structure decisions. The arms control process, in general, and SALT I and SALT II in particular, is discussed as an integral and dynamic component of the strategic debate, fundamentally affecting the nation's security policies. The implications of modern weapons technology, and the problems inherent in preserving strategic stability between adversary nations with asymmetries in military force structures and doctrines, are also discussed. Further, the study focuses on the question of whether or not nuclear superiority can be considered relevant under the contemporary international conditions

Assessment of Sampling Error Associated with Collection and Analysis of Soil Samples at a Firing Range Contaminated with HMX

National Research Council Canada - National Science Library

Jenkins, Thomas F

1997-01-01

Short-range and mid-range (grid size) spatial heterogeneity in explosives concentrations within surface soils was studied at an active antitank firing range at the Canadian Force Base-Valcartier, Val-Belair, Quebec...

Pion condensation and density isomerism in nuclear matter

International Nuclear Information System (INIS)

Hecking, P.; Weise, W.

1979-01-01

The possible existence of density isomers in nuclear matter, induced by pion condensation, is discussed; the nuclear equation of state is treated within the framework of the sigma model. Repulsive short-range baryon-baryon correlations, the admixture of Δ (1232) isobars and finite-range pion-baryon vertex form factors are taken into account. The strong dependence of density isomerism on the high density extrapolation of the equation of state for normal nuclear matter is also investigated. We find that, once finite range pion-baryon vertices are introduced, the appearance of density isomers becomes unlikely

EXAFS study of short range order in Fe-Zr amorphous alloys

International Nuclear Information System (INIS)

Fernandez-Gubieda, M.L.; Gorria, P.; Barandiaran, J.M.; Barquin, L.F.

1995-01-01

Room temperature X-ray absorption spectra on Fe K-edge have been performed in Fe 100-x-y Zr x B y and Fe 86 Zr 7 Cu 1 B 6 alloys (x=7, 7.7, 9; y=0, 2, 4, 6). Fe-Fe coordination number and interatomic distances do not change in any sample. However, small changes in the Fe-Zr short range order, which could explain the evolution of the magnetic properties, have been observed. (orig.)

Bottom boundary layer forced by finite amplitude long and short surface waves motions

Science.gov (United States)

Elsafty, H.; Lynett, P.

2018-04-01

A multiple-scale perturbation approach is implemented to solve the Navier-Stokes equations while including bottom boundary layer effects under a single wave and under two interacting waves. In this approach, fluid velocities and the pressure field are decomposed into two components: a potential component and a rotational component. In this study, the two components are exist throughout the entire water column and each is scaled with appropriate length and time scales. A one-way coupling between the two components is implemented. The potential component is assumed to be known analytically or numerically a prior, and the rotational component is forced by the potential component. Through order of magnitude analysis, it is found that the leading-order coupling between the two components occurs through the vertical convective acceleration. It is shown that this coupling plays an important role in the bottom boundary layer behavior. Its effect on the results is discussed for different wave-forcing conditions: purely harmonic forcing and impurely harmonic forcing. The approach is then applied to derive the governing equations for the bottom boundary layer developed under two interacting wave motions. Both motions-the shorter and the longer wave-are decomposed into two components, potential and rotational, as it is done in the single wave. Test cases are presented wherein two different wave forcings are simulated: (1) two periodic oscillatory motions and (2) short waves interacting with a solitary wave. The analysis of the two periodic motions indicates that nonlinear effects in the rotational solution may be significant even though nonlinear effects are negligible in the potential forcing. The local differences in the rotational velocity due to the nonlinear vertical convection coupling term are found to be on the order of 30% of the maximum boundary layer velocity for the cases simulated in this paper. This difference is expected to increase with the increase in wave

Simulation methods for nuclear production scheduling

International Nuclear Information System (INIS)

Miles, W.T.; Markel, L.C.

1975-01-01

Recent developments and applications of simulation methods for use in nuclear production scheduling and fuel management are reviewed. The unique characteristics of the nuclear fuel cycle as they relate to the overall optimization of a mixed nuclear-fossil system in both the short-and mid-range time frame are described. Emphasis is placed on the various formulations and approaches to the mid-range planning problem, whose objective is the determination of an optimal (least cost) system operation strategy over a multi-year planning horizon. The decomposition of the mid-range problem into power system simulation, reactor core simulation and nuclear fuel management optimization, and system integration models is discussed. Present utility practices, requirements, and research trends are described. 37 references

Energy System Expectations for Nuclear in the 21. Century: A Plausible Range

International Nuclear Information System (INIS)

Langlois, Lucille M.; McDonald, Alan; Rogner, Hans-Holger; Vera, Ivan

2002-01-01

This paper outlines a range of scenarios describing what the world's energy system might look like in the middle of the century, and what nuclear energy's most profitable role might be. The starting point is the 40 non-greenhouse-gas-mitigation scenarios in the Special Report on Emissions Scenarios (SRES) of the Intergovernmental Panel on Climate Change (IPCC, 2000). Given their international authorship and comprehensive review by governments and scientific experts, the SRES scenarios are the state of the art in long-term energy scenarios. However, they do not present the underlying energy system structures in enough detail for specific energy technology and infrastructure analyses. This paper therefore describes initial steps within INPRO (The International Project on Innovative Nuclear Reactors and Fuel Cycles of the International Atomic Energy Agency) to translate the SRES results into a range of possible nuclear energy technology requirements for mid-century. The paper summarizes the four SRES scenarios that will be used in INPRO and the reasons for their selection. It provides illustrative examples of the sort of additional detail that is being developed about the overall energy system implied by each scenario, and about specific scenario features particularly relevant to nuclear energy. As recommended in SRES, the selected scenarios cover all four SRES 'story-line families'. The energy system translations being developed in INPRO are intended to indicate how energy services may be provided in mid-century and to delineate likely technology and infrastructure implications. They will indicate answers to questions like the following. The list is illustrative, not comprehensive. - What kind of nuclear power plants will best fit the mid-century energy system? - What energy forms and other products and services provided by nuclear reactors will best fit the mid-century energy system? - What would be their market shares? - How difficult will it be to site new nuclear

Towards an understanding of the nuclear potential

International Nuclear Information System (INIS)

Richards, D.G.; Sinclair, D.K.; Sivers, D.

1988-01-01

The formalism for investigating the /bar Q/q/bar Q/q system on the lattice is constructed. We describe how the model may be used to study the nuclear potential, and present some preliminary results on the range of the nuclear force. 6 refs., 4 figs., 1 tab

Calculation of the well depth parameter to the nuclear potential

International Nuclear Information System (INIS)

Kim, Y.U.; Kim, Y.J.

1984-01-01

Well depth parameter S or range correction factor S-1 is computed for several nuclear potentials such as square, Gaussian, exponential and Yukawa wells. A simple central force is assumed for nuclear potential between nucleons. We adopted only two parameters for potentials and attempted to clarify the fundamental nature of the nuclear forces that bind a proton and a neutron into a deuteron. Results thus obtained were used for an estimate of first order correction to simple square well model. (Author)

Short-pulse laser interactions with disordered materials and liquids

Energy Technology Data Exchange (ETDEWEB)

Phinney, L.M.; Goldman, C.H.; Longtin, J.P.; Tien, C.L. [Univ. of California, Berkeley, CA (United States)

1995-12-31

High-power, short-pulse lasers in the picosecond and subpicosecond range are utilized in an increasing number of technologies, including materials processing and diagnostics, micro-electronics and devices, and medicine. In these applications, the short-pulse radiation interacts with a wide range of media encompassing disordered materials and liquids. Examples of disordered materials include porous media, polymers, organic tissues, and amorphous forms of silicon, silicon nitride, and silicon dioxide. In order to accurately model, efficiently control, and optimize short-pulse, laser-material interactions, a thorough understanding of the energy transport mechanisms is necessary. Thus, fractals and percolation theory are used to analyze the anomalous diffusion regime in random media. In liquids, the thermal aspects of saturable and multiphoton absorption are examined. Finally, a novel application of short-pulse laser radiation to reduce surface adhesion forces in microstructures through short-pulse laser-induced water desorption is presented.

Multi-channel, passive, short-range anti-aircraft defence system

Science.gov (United States)

Gapiński, Daniel; Krzysztofik, Izabela; Koruba, Zbigniew

2018-01-01

The paper presents a novel method for tracking several air targets simultaneously. The developed concept concerns a multi-channel, passive, short-range anti-aircraft defence system based on the programmed selection of air targets and an algorithm of simultaneous synchronisation of several modified optical scanning seekers. The above system is supposed to facilitate simultaneous firing of several self-guided infrared rocket missiles at many different air targets. From the available information, it appears that, currently, there are no passive self-guided seekers that fulfil such tasks. This paper contains theoretical discussions and simulations of simultaneous detection and tracking of many air targets by mutually integrated seekers of several rocket missiles. The results of computer simulation research have been presented in a graphical form.

Some highlights in few-body nuclear physics.

Energy Technology Data Exchange (ETDEWEB)

Holt, R. J.

2000-12-07

During the past five years, there have been tremendous advances in both experiments and theoretical calculations in few-body nuclear systems. Advances in technology have permitted experiments of unprecedented accuracy. Jefferson Laboratory has begun operation and the first round of experimental results have become available. New polarization techniques have been exploited at a number of laboratories, in particular, at Jefferson Lab, IUCF, RIKEN, NIKHEF, Mainz, MIT-Bates and HERMES. Some of these results will be shown here. In addition, there have been tremendous advances in few-body theory. Five modern two-nucleon potentials have which describe the nucleon-nucleon data extremely well have become available. A standard model of nuclear physics based on these two nucleon potentials as well as modern three-nucleon forces has emerged. This standard model has enjoyed tremendous success in the few body systems. Exact three-body calculations have been extended into the continuum in order to take full advantage of scattering data in advancing our understanding of the the few-nucleon system. In addition, the application of chiral symmetry has become an important constraint on nucleon-nucleon as well as three-nucleon forces. As a result of all these efforts, we have seen rapid developments in the three-body force. Despite these advances, there remain some extremely important open issues: (1) What is the role of quarks and gluons in nuclear structure; (2) Can we distinguish meson exchange from quark interchange; (3) Is few-body theory sufficient to describe simultaneously the mass 2, 3 and 4 form factors; (4) What is the isospin and spin dependence of the three-body force; (5) Are there medium modifications for nucleons and mesons in nuclei; (6) Is there an enhancement of antiquarks or pions in nuclei related to the binding; and (7) Are short range correlations observable in nuclei? In this paper the author summarizes the status of our understanding of these issues.

Report of Task Force for review of nuclear waste management. Draft

International Nuclear Information System (INIS)

1978-02-01

Some of the findings of the Task Force are: a majority of independent technical experts have concluded that high-level waste can be safely disposed in geological media, but validation of the specific technical choices will be an important element of the licensing process. Reprocessing is not required for the safe disposal of commercial spent fuel. Consideration should be given to an early demonstration of the geologic disposal of a limited number of spent fuel assemblies in the waste Isolation Pilot Plant. The Spent Fuel Policy announced by President Carter in October 1977 must be integrated with the Waste Management Policy. The Task Force report highlights the importance of away from reactor storage that occurs between on-site storage of spent fuel at utilities and ultimate disposal. The target for initial operation in 1985 os a National Waste Repository for the permanent disposal of commercial high-level waste as spent fuel may not be met; this does not affect the early 1980s schedule for the Waste Isolation Pilot Plant. The responsibility for the ultimate disposal for all forms of nuclear waste should be with the Federal Government and long-term waste disposal facilities should be subject to NRC licensing. The NEPA process is an essential part of the nuclear waste management program and Department of Energy efforts in this regard must be strengthened. Policy and program management responsibility for Waste Management should be raised to a higher level in the Department of Energy. There are substantial budgetary impacts of the Task Force recommendations and legislation would be required to carry out many of the suggested changes

Study of short range order in alloy of glassy metals and effect of neutron irradiation on them

International Nuclear Information System (INIS)

Habibi, S.; Banaee, N.; Salman, M.; Gupta, A.; Principi, G.

2000-04-01

In this paper, we have studied a series of glassy metals with composition Fe 78-x Ni x Si 8 B 14 with x=0, 15, 25,38,53, 58. We have used Moessbauer spectroscopy to get information about short range order and local structure in these alloys. The specimens are exposed to neutron irradiation to perturb local structure and their short range order. The hyperfine parameters obtained from spectra before and after n-irradiation and are compared

Components and renewal parts in the nuclear power industry

International Nuclear Information System (INIS)

Clark, T.F. Jr.

1986-01-01

This paper indicates that the nuclear parts industry has been forced to make major investments in time, personnel and financial resources in order to solve short term/emergency procurement problems. What is required, as was previously indicated, is a coordinated industry-wide effort toward long range planning and implementation of a program that addresses these issues. The industry is developing programs directed toward inventory optimization and ''innovative-creative'' financing of manufacturing inventory/work-in-process in an effort to significantly reduce delivery lead times. Product transition, utilization of cancelled plant equipment, equipment qualification programs, and dedication of commercially manufactured/procured parts and components for safety related application continue to be major elements of our program to support current utility requirements

Short Interspersed Nuclear Element (SINE) Sequences in the Genome of the Human Pathogenic Fungus Aspergillus fumigatus Af293.

Science.gov (United States)

Kanhayuwa, Lakkhana; Coutts, Robert H A

2016-01-01

Novel families of short interspersed nuclear element (SINE) sequences in the human pathogenic fungus Aspergillus fumigatus, clinical isolate Af293, were identified and categorised into tRNA-related and 5S rRNA-related SINEs. Eight predicted tRNA-related SINE families originating from different tRNAs, and nominated as AfuSINE2 sequences, contained target site duplications of short direct repeat sequences (4-14 bp) flanking the elements, an extended tRNA-unrelated region and typical features of RNA polymerase III promoter sequences. The elements ranged in size from 140-493 bp and were present in low copy number in the genome and five out of eight were actively transcribed. One putative tRNAArg-derived sequence, AfuSINE2-1a possessed a unique feature of repeated trinucleotide ACT residues at its 3'-terminus. This element was similar in sequence to the I-4_AO element found in A. oryzae and an I-1_AF long nuclear interspersed element-like sequence identified in A. fumigatus Af293. Families of 5S rRNA-related SINE sequences, nominated as AfuSINE3, were also identified and their 5'-5S rRNA-related regions show 50-65% and 60-75% similarity to respectively A. fumigatus 5S rRNAs and SINE3-1_AO found in A. oryzae. A. fumigatus Af293 contains five copies of AfuSINE3 sequences ranging in size from 259-343 bp and two out of five AfuSINE3 sequences were actively transcribed. Investigations on AfuSINE distribution in the fungal genome revealed that the elements are enriched in pericentromeric and subtelomeric regions and inserted within gene-rich regions. We also demonstrated that some, but not all, AfuSINE sequences are targeted by host RNA silencing mechanisms. Finally, we demonstrated that infection of the fungus with mycoviruses had no apparent effects on SINE activity.

Magnetic susceptibility as a method of investigation of short-range order in strongly nonstoichiometric carbides

International Nuclear Information System (INIS)

Nazarova, S.Z.; Gusev, A.I.

2001-01-01

Magnetic susceptibility in disordered and ordered carbides of transition metals (M = Ti, Zr, Hf, Nb, Ta) was studied, the results are generalized. It was ascertained that the change in carbide susceptibility induced by deviation from stoichiometry stems from specific features of electronic spectra of the compounds. The use of magnetic susceptibility for determining structural disorder-order transitions is discussed. It is shown that change in the contribution made by orbital paramagnetism, resulting from short-range order formation, is the reason of decrease in susceptibility of nonstoichiometric carbides during the ordering. Experimentally obtained data on susceptibility permitted evaluating short- and far-range order parameters in NbC y , TaC y , TiC y and HfC y carbides [ru

Nuclear energy density functional from chiral pion-nucleon dynamics revisited

Science.gov (United States)

Kaiser, N.; Weise, W.

2010-05-01

We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from 1 π-exchange, iterated 1 π-exchange, and irreducible 2 π-exchange with intermediate Δ-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass M(ρ) entering the energy density functional is identical to the one of Fermi-liquid theory when employing the improved density-matrix expansion. The strength F(ρ) of the ( surface-term as provided by the pion-exchange dynamics is in good agreement with that of phenomenological Skyrme forces in the density region ρ/2short-range spin-orbit interaction. The strength function F(ρ) multiplying the square of the spin-orbit density comes out much larger than in phenomenological Skyrme forces and it has a pronounced density dependence.

Perturbation theory for short-range weakly-attractive potentials in one dimension

Energy Technology Data Exchange (ETDEWEB)

Amore, Paolo, E-mail: paolo.amore@gmail.com [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico); Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CONICET), Division Química Teórica, Blvd. 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

2017-03-15

We have obtained the perturbative expressions up to sixth order for the energy of the bound state in a one dimensional, arbitrarily weak, short range finite well, applying a method originally developed by Gat and Rosenstein Ref. [1]. The expressions up to fifth order reproduce the results already known in the literature, while the sixth order had not been calculated before. As an illustration of our formulas we have applied them to two exactly solvable problems and to a nontrivial problem.

Short- and medium-range order in a Zr73Pt27 glass: Experimental and simulation studies

International Nuclear Information System (INIS)

Wang, S.Y.; Wang, C.Z.; Li, M.Z.; Huang, L.; Ott, R.T.; Kramer, M.J.; Sordelet, D.J.; Ho, K.M.

2008-01-01

The structure of a Zr 73 Pt 27 metallic glass, which forms a Zr 5 Pt 3 (Mn 5 Si 3 -type) phase having local atomic clusters with distorted icosahedral coordination during the primary crystallization, has been investigated by means of x-ray diffraction and combining ab initio molecular-dynamics (MD) and reverse Monte Carlo (RMC) simulations. The ab initio MD simulation provides an accurate description of short-range structural and chemical ordering in the glass. A three-dimensional atomistic model of 18?000 atoms for the glass structure has been generated by the RMC method utilizing both the structure factor S(k) from x-ray diffraction experiment and the partial pair-correlation functions from ab initio MD simulation. Honeycutt and Andersen index and Voronoi cell analyses, respectively, were used to characterize the short- and medium-range order in the atomistic structure models generated by ab initio MD and RMC simulations. The ab initio results show that an icosahedral type of short-range order is predominant in the glass state. Furthermore, analysis of the atomic model from the constrained RMC simulations reveals that the icosahedral-like clusters are packed in arrangements having higher-order correlations, thus establishing medium-range topological order up to two or three cluster shells.

A short-range weather prediction system for South Africa based on a multi-model approach

CSIR Research Space (South Africa)

Landman, S

2012-10-01

Full Text Available stream_source_info Landman5_2012.pdf.txt stream_content_type text/plain stream_size 44898 Content-Encoding ISO-8859-1 stream_name Landman5_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 1 A short... to be skillful. Moreover, the system outscores the forecast skill of the individual models. Keywords: short-range, ensemble, forecasting, precipitation, multi-model, verification Tel: +27 12 367 6054...

Amendment to the Decree of the Slovak Nuclear Regulatory Authority on details concerning emergency planning in case of nuclear incident or accident

International Nuclear Information System (INIS)

Biharyová, Michaela

2018-01-01

Following up amendment to the Slovak Atomic Act, the Decree No. 55/2006 on details concerning emergency planning in case of nuclear incident or accident has also been amended now. Following a short introductory text by the author, the entire text of the ‘Decree of the Nuclear Regulatory Authority of the Slovak Republic No 9/2018 Coll. of 2 January 2018 amending Decree of the Nuclear Regulatory Authority of the Slovak Republic No 55/2006 Coll. on details in emergency planning in case of nuclear incident or accident as amended by Decree No. 35/2012 Coll.’ is reproduced. The Amendment entered into force 1 February 2018. (orig.)

The future of U.S.-Russia nuclear arms control

Science.gov (United States)

Pifer, Steven

2017-11-01

Nuclear arms control has long made contributions to U.S.-Soviet and U.S.-Russian security, but the current regime is at risk. The 1987 Intermediate-range Nuclear Forces Treaty may be headed for collapse. Both the United States and Russia are modernizing their strategic forces, and the fate of the 2010 New Strategic Arms Reduction Treaty is unclear. In the unlikely case that the sides are prepared to go beyond New START, there are ways to address further reductions and related issues. A collapse of the arms control regime, on the other hand, would mean the end of constraints on U.S. and Russian nuclear forces, a significant loss of transparency, and potential costs to U.S. security.

Determination of thermodynamical coefficients for Mo-W alloys according to short-range order parameters

International Nuclear Information System (INIS)

Erokhin, L.N.; Mokrov, A.P.; Shivrin, O.N.; Khanina, N.I.

1986-01-01

A method is proposed for determining thermodynamical coefficients according to short-range order parameters. The method approbation for Mo-W alloys has shown a good agreement between the thermodynamical and diffusion data. The Mo-W system in the concentration range under study is close to the ideal one. The calculated relative error of determination of interdiffusion coefficients in alloys of the Mo-W system does not exceed 16%

Anatomy of double beta decay nuclear matrix elements

Energy Technology Data Exchange (ETDEWEB)

Vogel, Petr, E-mail: pxv@caltech.ed [Kellogg Radiation Laboratory 106-38 Caltech. Pasadena, CA 91125 (United States)

2009-06-01

The necessary ingredients for a realistic evaluation of the 0vbetabeta nuclear matrix elements are reviewed. It is argued that the short range nucleon correlations, nucleon finite size, and higher order nuclear currents need to be included in the calculation, even though a consensus on the best way to treat all of these effects has not been reached. Another positive development is the realization that the two alternative and complementary methods, the Quasiparticle Random Phase Approximation and the Nuclear Shell Model, agree on many aspects of the calculation, in particular on the competition, or cancelation, between the contribution of nuclear pairing on one hand, and the other pieces of interaction that result in admixtures of broken pairs or higher seniority states on the other hand. The relatively short range (r <= 2-3 fm) of the effective 0vbetabeta operator found in both methods is a consequence of that competition.

Optimal design of a vehicle magnetorheological damper considering the damping force and dynamic range

International Nuclear Information System (INIS)

Nguyen, Quoc-Hung; Choi, Seung-Bok

2009-01-01

This paper presents an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function. The objective function consists of the damping force, the dynamic range, and the inductive time constant of the damper. After describing the configuration of the MR damper, the damping force and dynamic range are obtained on the basis of the Bingham model of an MR fluid. Then, the control energy (power consumption of the damper coil) and the inductive time constant are derived. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initial damper. Subsequently, the optimization procedure, using a golden-section algorithm and a local quadratic fitting technique, is constructed via commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR damper, which are constrained in a specific cylindrical volume defined by its radius and height, are determined and a comparative work on damping force and inductive time constant between the initial and optimal design is undertaken

The Spectrum of Particles with Short-Ranged Interactions in a Harmonic Trap

Directory of Open Access Journals (Sweden)

Metsch B. Ch.

2010-04-01

Full Text Available The possibility to control short-ranged interactions of cold gases in optical traps by Feshbachresonances makes these systems ideal candidates to study universal scaling properties and Efimov physics. The spectrum of particles in a trap, idealised by a harmonic oscillator potential, in the zero range limit with 2- and 3-particle contact interactions is studied numerically. The Hamiltonian is regularised by restricting the oscillator basis and the coupling constants are tuned such that the ground state energies of the 2- and 3-particle sector are reproduced [1],[2]. Results for 2-, 3-, and 4 particle systems are presented and compared to exact results [3],[4].

Comparison of impact forces, accelerations and ankle range of motion in surfing-related landing tasks.

Science.gov (United States)

Lundgren, Lina E; Tran, Tai T; Nimphius, Sophia; Raymond, Ellen; Secomb, Josh L; Farley, Oliver R L; Newton, Robert U; Sheppard, Jeremy M

2016-01-01

This study aimed to describe the impact forces, accelerations and ankle range of motion in five different landing tasks that are used in training and testing for competitive surfing athletes, to assist coaches in the prescription of landing task progression and monitoring training load. Eleven competitive surfing athletes aged 24 ± 7 years participated, and inertial motion sensors were fixed to the anterior aspect of the feet, mid-tibial shafts, sacrum and eighth thoracic vertebrae on these athletes. Three tasks were performed landing on force plates and two tasks in a modified gymnastics set-up used for land-based aerial training. Peak landing force, resultant peak acceleration and front and rear side ankle dorsiflexion ranges of motion during landing were determined. The peak acceleration was approximately 50% higher when performing aerial training using a mini-trampoline and landing on a soft-density foam board, compared to a similar landing off a 50 cm box. Furthermore, the ankle ranges of motion during the gymnastic type landings were significantly lower than the other landing types (P ≤ 0.05 and P ≤ 0.001), for front and rear sides, respectively. Conclusively, increased task complexity and specificity of the sport increased the tibial peak acceleration, indicating greater training load.

Short, intermediate and mesoscopic range order in sulfur-rich binary glasses

International Nuclear Information System (INIS)

Bychkov, E.; Miloshova, M.; Price, D.L.; Benmore, C.J.; Lorriaux, A.

2006-01-01

Pulsed neutron and high-energy X-ray diffraction, small-angle neutron scattering, Raman spectroscopy and DSC were used to study structural changes on the short, intermediate and mesoscopic range scale for sulfur-rich AsS x (x (ge) 1.5) and GeS x (x (ge) 2) glasses. Two structural regions were found in the both systems. (1) Between stoichiometric (As 2 S 3 and GeS 2 ) and 'saturated' (AsS 2.2 and GeS 2.7 ) compositions, excessive sulfur atoms form sulfur dimers and/or short chains, replacing bridging sulfur in corner-sharing AsS 3/2 and GeS 4/2 units. (2) Above the 'saturated' compositions at (As) x system) appear in the glass network. The glasses become phase separated with the domains of 20-50 (angstrom), presumably enriched with sulfur rings. The longer chains Sn are not stable and crystallize to c-S 8 on ageing of a few days to several months, depending on composition.

Direct measurements of intermolecular forces by chemical force microscopy

Science.gov (United States)

Vezenov, Dmitri Vitalievich

1999-12-01

Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the

Isotopes a very short introduction

CERN Document Server

Ellam, Rob

2016-01-01

An isotope is a variant form of a chemical element, containing a different number of neutrons in its nucleus. Most elements exist as several isotopes. Many are stable while others are radioactive, and some may only exist fleetingly before decaying into other elements. In this Very Short Introduction, Rob Ellam explains how isotopes have proved enormously important across all the sciences and in archaeology. Radioactive isotopes may be familiar from their use in nuclear weapons, nuclear power, and in medicine, as well as in carbon dating. They have been central to establishing the age of the Earth and the origins of the solar system. Combining previous and new research, Ellam provides an overview of the nature of stable and radioactive isotopes, and considers their wide range of modern applications. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subjec...

Short-range order of amorphous FeNiB alloy after neutron irradiation

International Nuclear Information System (INIS)

Miglierini, M.; Sitek, J.; Baluch, S.; Cirak, J.; Lipka, J.

1990-01-01

Transmission Moessbauer spectroscopy was used to study irradiation-induced changes in the short-range order of an amorphous Fe 80-x Ni x B 20 alloy. Neutron irradiation led to an increase of the width of a hyperfine field distribution implying atomic rearrangement towards disordering. Changes in a mean value of a HFD and Moessbauer line areas can be associated with a reorientation of spins due to radiation damage. (orig.)

Directional and short-range ordering kinetics in metallic alloys, crystalline and amorphous

International Nuclear Information System (INIS)

Hillairet, J.

1985-01-01

This presentation describes the methods (resistometric and anelastic) based on analysis of stress-induced directional ordering and short-range ordering and their application to the study of metallic alloys, crystalline and amorphous. It focuses on the determination of the atomic mobility and point defect properties. It discusses also the structural information which can be gained by Zener relaxation studies about the order-disorder transition and self-induced directional ordering phenomena

Changes in structure of the short-range order of the InP melt when heated

International Nuclear Information System (INIS)

Glazov, V.M.; Dovletov, K.; Nashel'skij, A.Ya.; Mamedov, M.M.

1977-01-01

An investigation of the temperature dependence of the InP viscosity has indicated an ''after-melting'' effect similar to that observed in other A 3 V 5 compounds having a sphalerite structure. The termodynamic parameters of the viscous flow of indium phosphide melt have been calculated, and a suggestion has been made on the loosening of the short-range order structure of the melt during the period preceding solidification. With the similarity in the behaviour of InP and of A 3 Sb compound melts as a basis, a suggestion has been put forward that the influence of the thermal dissociation upon the character of the changes in the short-range order structure directly after transition from the solid to the liquid phase is negligible

Facilitating the entry into force and implementation of the Amendment to the Convention on the Physical Protection of Nuclear Material: Observations, challenges and benefits

International Nuclear Information System (INIS)

Johnson, Peri Lynne; )

2014-01-01

Amendment to enter into force is clear and its benefits are recognised, further consideration needs to be given to identifying why it has not yet entered into force. More particularly, what are the reasons why nearly half of the current CPPNM states parties, including those with and without nuclear material and nuclear facilities, have still not joined the Amendment? Also, what challenges do they face in joining and effectively implementing the instrument? This article will seek to provide answers and also to identify some benefits of the Amendment. Part A of this article places the Amendment into context by identifying the relevant legal instruments comprising the international legal framework for nuclear security. Part B highlights some of the Amendment's new and extended provisions. The IAEA Secretariat's internal Plan of Action on Facilitating Adherence to and Implementation of the Amendment (the 'Plan of Action') is highlighted in Part C, which also addresses relevant IAEA activities by identifying the broad range of services provided to IAEA member states. Part D identifies some observations and challenges associated with the entry into force and implementation of the Amendment, the main focus is on its provisions, which are likely to require changes to the national legislative framework. Finally, Part E of this article concludes with some identified potential benefits of joining the Amendment, in particular, those considered by the IAEA Advisory Group on Nuclear Security ('AdSec'). (author)

Range measurements and track kinetics in Dielectric Nuclear Track Detectors (DNTDs)

Energy Technology Data Exchange (ETDEWEB)

Aframian, A

1981-01-01

Observations of nuclear track development profiles and the kinetics of etched tracks in sensitive dielectric nuclear track detectors indicate three separate phases: the inception phase or the cone phase, the transition phase and the sphere phase. Continued etching of the sphere phase to through-tracks yields accurate range data for particles of different masses and energies and minimum critical angles of registration for each particle. The present results show an energy resolution of 40 keV (fwhm) for 5.48 MeV alpha-particles emitted from Am-241.

Targeted identification of short interspersed nuclear element families shows their widespread existence and extreme heterogeneity in plant genomes.

Science.gov (United States)

Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

2011-09-01

Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5' truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3' end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families.

Exploiting orbital effects for short-range extravehicular transfers

Science.gov (United States)

Williams, Trevor; Baughman, David

The problem studied in this paper is that of using Simplified Aid for Extravehicular Activity (EVA) Rescue (SAFER) to carry out efficient short-range transfers from the payload bay of the Space Shuttle Orbiter to the vicinity of the underside of the vehicle, for instance for inspection and repair of thermal tiles or umbilical doors. Trajectories are shown to exist, for the shuttle flying noise forward and belly down, that take the astronaut to the vicinity of the underside with no thrusting after the initial push-off. However, these trajectories are too slow to be of practical interest, as they take roughly an hour to execute. Additionally, they are quite sensitive to errors in the initial push-off rates. To overcome both of these difficulties, trajectories are then studied which include a single in-flight impulse of small magnitude ( in the range 0.1 - 0.4 fps). For operational simplicity, this impulse is applied towards the Orbiter at the moment when the line-of -sight of the EVA crewmember is tangential to the underside of the vehicle. These trajectories are considerably faster than the non-impulsive ones: transit times of less than 10 minutes are achievable. Furthermore, the man-in-the-loop feedback scheme used for impulse timing greatly reduces the sensitivity to initial velocity errors. Finally, similar one-impulse trajectories are also shown to exist for the Orbiter in a gravity-gradient attitiude.

Neutron diffraction study on the medium and short-range order of ternary chalcogenide glasses

Czech Academy of Sciences Publication Activity Database

Neov, S.; Gerasimova, I.; Skordeva, E.; Arsova, D.; Pamukchieva, V.; Mikula, Pavol; Lukáš, Petr; Sonntag, R.

1999-01-01

Roč. 34, - (1999), s. 3669-3676 ISSN 0022-2461 R&D Projects: GA ČR GV202/97/K038 Keywords : neutron diffraction * short-range order * chalcogenide glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.786, year: 1999

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a...

Searching for Short Range Correlations Using (e,e'NN) Reactions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bin [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2003-02-01

Electron induced two nucleon knockout reactions (e,e'pp) and (e,e'np) were performed for ³He, ⁴He, and ¹²C nuclei with incident energies of 2.261 GeV and 4.461 GeV using the CLAS detector at Jefferson Lab. Events with missing momenta lower than the Fermi level and missing energies smaller than the pion threshold were studied. The residual system was assumed to be a spectator and the process was considered as a quasi-free knockout of an NN pair. The data showed that the initial momentum extends up to 800 MeV/c with considerable strength. The cross sections for ³He(e,e'pp)n were compared to the calculations of J.M. Laget. It was found that the final state interactions (FSI) and the meson exchange currents (MEC) dominate the cross sections and the short range properties of the NN pair were substantially undermined. However, the node of the S state wave function of the pp pair at around 400 MeV/c initial momentum starts to be recognizable in the 4.461 GeV data. The data and the theory suggest that with higher momentum transfers, especially in the region x_Bj > 1, the competing processes such as FSI and MEC will be less important and the detailed study of the short-range properties of nucleons inside nuclei will be more desirable.

A force measurement system based on an electrostatic sensing and actuating technique for calibrating force in a micronewton range with a resolution of nanonewton scale

International Nuclear Information System (INIS)

Chen, Sheng-Jui; Pan, Sheau-Shi

2011-01-01

This paper introduces a force measurement system recently established at the Center for Measurement Standards, Industrial Technology Research Institute for calibrating forces in a micronewton range with a resolution of a few nanonewtons. The force balance consists of a monolithic flexure stage and a specially made capacitor for electrostatic sensing and actuating. The capacitor is formed by three electrodes which can be utilized as a capacitive position sensor and an electrostatic force actuator at the same time. Force balance control is implemented with a digital controller by which the signal of the stage deflection is acquired, filtered and fed back to the electrostatic force driver to bring the flexure stage to the null position. The detailed description of the apparatus including the design of a monolithic flexure stage, principle of capacitive position sensing/electrostatic actuation and the force balance control is given in the paper. Finally, we present the results of electrostatic force calibration and the weighing of a 1 mg wire weight

Introducing a new family of short-range potentials and their numerical solutions using the asymptotic iteration method

Science.gov (United States)

Assi, I. A.; Sous, A. J.

2018-05-01

The goal of this work is to derive a new class of short-range potentials that could have a wide range of physical applications, specially in molecular physics. The tridiagonal representation approach has been developed beyond its limitations to produce new potentials by requiring the representation of the Schrödinger wave operator to be multidiagonal and symmetric. This produces a family of Hulthén potentials that has a specific structure, as mentioned in the introduction. As an example, we have solved the nonrelativistic wave equation for the new four-parameter short-range screening potential numerically using the asymptotic iteration method, where we tabulated the eigenvalues for both s -wave and arbitrary l -wave cases in tables.

Joint Maneuver Test Range on Eglin Air Force Base, Florida Final Environmental Assessment

Science.gov (United States)

2009-12-14

ir Force B ase, Florida Page 3-2 Final E nvironm ental A ssessm ent A ffected E nvironm ent W ater R esources Figure 3-1. Physical and...nvironm ent W ater R esources Figure 3-2. Physical and Biological Resources Within Range B-9 Existing Components 14. Hills!Qoss Slope Legend --Creek

The Role of a Short-Term Education Programme in International Nuclear Human Resource Development and Knowledge Management

International Nuclear Information System (INIS)

Murakami, K.; Uesaka, M.

2016-01-01

Full text: The Nuclear Energy Management School is proposed as a good tool to structure the experiences of industries. The importance of a short-term international education programme for gathering knowledge regarding nuclear embarkation projects is discussed in this paper. The results of evaluating education efficiency from 2013 to 2016 will also be introduced in this presentation (or poster). (author

A novel ultra-short scanning nuclear microprobe: Design and preliminary results

International Nuclear Information System (INIS)

Lebed, S.; Butz, T.; Vogt, J.; Reinert, T.; Spemann, D.; Heitmann, J.; Stachura, Z.; Lekki, J.; Potempa, A.; Styczen, J.; Sulkio-Cleff, B.

2001-01-01

The paper describes an optimized scanning nuclear microprobe (MP) with a new ultra-short (total length of 1.85 m) probe forming system based on a divided Russian quadruplet (DRQ) of magnetic quadrupole lenses. Modern electrostatic accelerators have a comparatively high beam brightness of about 10-25 pA/μm 2 /mrad 2 /MeV. This allows the MP proposed to provide a high lateral resolution even with large (1%) parasitic (sextupole and octupole) pole tip field components in all lenses. The features of the design permit the MP operation in the high current and low current modes with a short working distance and inexpensive quadrupole lenses. A new quadrupole doublet design has been developed for the MP. In the present work the calculated features of the new MP are compared with preliminary experimental results obtained with a similar system (total length of 2.3 m) at the INP in Cracow. The new MP is promising for studies of solids or biological samples with high resolutions (0.08-2 μm) in both modes under ambient conditions. A vertical version of the ultra-short MP can be very useful for single ion bombardments of living cells

Short range part of the NN interaction: Equivalent local potentials from quark exchange kernels

International Nuclear Information System (INIS)

Suzuk, Y.; Hecht, K.T.

1983-01-01

To focus on the nature of the short range part of the NN interaction, the intrinsically nonlocal interaction among the quark constituents of colorless nucleons is converted to an equivalent local potential using resonating group kernels which can be evaluated in analytic form. The WKB approximation based on the Wigner transform of the nonlocal kernels has been used to construct the equivalent potentials without recourse to the long range part of the NN interaction. The relative importance of the various components of the exchange kernels can be examined: The results indicate the importance of the color magnetic part of the exchange kernel for the repulsive part in the (ST) = (10), (01) channels, in particular since the energy dependence of the effective local potentials seems to be set by this term. Large cancellations of color Coulombic and quark confining contributions, together with the kinetic energy and norm exchange terms, indicate that the exact nature of the equivalent local potential may be sensitive to the details of the parametrization of the underlying quark-quark interaction. The equivalent local potentials show some of the characteristics of the phenomenological short range terms of the Paris potential

Analytic nuclear forces and molecular properties from full configuration interaction quantum Monte Carlo

International Nuclear Information System (INIS)

Thomas, Robert E.; Overy, Catherine; Opalka, Daniel; Alavi, Ali; Knowles, Peter J.; Booth, George H.

2015-01-01

Unbiased stochastic sampling of the one- and two-body reduced density matrices is achieved in full configuration interaction quantum Monte Carlo with the introduction of a second, “replica” ensemble of walkers, whose population evolves in imaginary time independently from the first and which entails only modest additional computational overheads. The matrices obtained from this approach are shown to be representative of full configuration-interaction quality and hence provide a realistic opportunity to achieve high-quality results for a range of properties whose operators do not necessarily commute with the Hamiltonian. A density-matrix formulated quasi-variational energy estimator having been already proposed and investigated, the present work extends the scope of the theory to take in studies of analytic nuclear forces, molecular dipole moments, and polarisabilities, with extensive comparison to exact results where possible. These new results confirm the suitability of the sampling technique and, where sufficiently large basis sets are available, achieve close agreement with experimental values, expanding the scope of the method to new areas of investigation

Short range order of selenite glasses

Czech Academy of Sciences Publication Activity Database

Neov, Dimitar; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr; Dimitriev, Y.

1999-01-01

Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA ČR GV202/97/K038; GA AV ČR KSK1048601 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.822, year: 1999

Muscle response to pneumatic hand tool torque reaction forces.

Science.gov (United States)

Radwin, R G; VanBergeijk, E; Armstrong, T J

1989-06-01

Surface electromyography was used for studying the effects of torque reaction force acting against the hand, on forearm muscle activity and grip force for five subjects operating right angle, air shut-off nutrunners. Four tools having increasing spindle torque were operated using short and long torque reaction times. Nutrunner spindle torque ranged between 30 Nm and 100 Nm. Short torque reaction time was considered 0.5 s while long torque reaction time was 2 s. Peak horizontal force was the greatest component of the reaction force acting against the hand and accounted for more than 97% of the peak resultant hand force. Peak hand force increased from 89 N for the smallest tool to 202 N for the largest tool. Forearm muscle rms EMG, scaled for grip force, indicated average flexor activity during the Torque-reaction phase was more than four times greater than the Pre-start and Post Shut-off phases, and two times greater than the Run-down phase. Flexor EMG activity during the Torque-reaction phase increased for increasing tool peak spindle torque. Average flexor rms EMG activity, scaled for grip force, during the Torque-reaction phase increased from 372 N for the 30 Nm nutrunner to 449 N for the 100 Nm nutrunner. Flexor rms EMG activity averaged during the Torque-reaction phase and scaled for grip force was 390 N for long torque reaction times and increased to 440 N for short torque reaction times. Flexor rms EMG integrated over the torque reaction phase was 839 Ns for long torque reaction times and decreased to 312 Ns for short torque reaction times. The average latency between tool spindle torque onset and peak initial flexor rms EMG for long torque reaction times was 294 ms which decreased to 161 ms for short torque reaction times. The average latency between peak tool spindle torque, just prior to tool shut-off, and peak final rms EMG for long torque reaction times was 97 ms for flexors and 188 ms for extensors, which decreased for short torque reaction times to 47

Nuclear and magnetic correlations in a topologically frustrated elemental magnet

International Nuclear Information System (INIS)

Stewart, J.R.; Andersen, K.H.; Cywinski, R.

1999-01-01

β-Mn is an exchange enhanced paramagnetic metal on the verge of antiferromagnetic order. However, strong spin-fluctuations and topological frustration prevent the formation of static long-range order. We investigate the magnetic properties of the β-MnAl series of alloys in which short-range magnetic order is achieved at low temperature. We extract the short-range nuclear and magnetic correlations using a novel reverse Monte-Carlo procedure. (authors)

Combining 2-m temperature nowcasting and short range ensemble forecasting

Directory of Open Access Journals (Sweden)

A. Kann

2011-12-01

Full Text Available During recent years, numerical ensemble prediction systems have become an important tool for estimating the uncertainties of dynamical and physical processes as represented in numerical weather models. The latest generation of limited area ensemble prediction systems (LAM-EPSs allows for probabilistic forecasts at high resolution in both space and time. However, these systems still suffer from systematic deficiencies. Especially for nowcasting (0–6 h applications the ensemble spread is smaller than the actual forecast error. This paper tries to generate probabilistic short range 2-m temperature forecasts by combining a state-of-the-art nowcasting method and a limited area ensemble system, and compares the results with statistical methods. The Integrated Nowcasting Through Comprehensive Analysis (INCA system, which has been in operation at the Central Institute for Meteorology and Geodynamics (ZAMG since 2006 (Haiden et al., 2011, provides short range deterministic forecasts at high temporal (15 min–60 min and spatial (1 km resolution. An INCA Ensemble (INCA-EPS of 2-m temperature forecasts is constructed by applying a dynamical approach, a statistical approach, and a combined dynamic-statistical method. The dynamical method takes uncertainty information (i.e. ensemble variance from the operational limited area ensemble system ALADIN-LAEF (Aire Limitée Adaptation Dynamique Développement InterNational Limited Area Ensemble Forecasting which is running operationally at ZAMG (Wang et al., 2011. The purely statistical method assumes a well-calibrated spread-skill relation and applies ensemble spread according to the skill of the INCA forecast of the most recent past. The combined dynamic-statistical approach adapts the ensemble variance gained from ALADIN-LAEF with non-homogeneous Gaussian regression (NGR which yields a statistical mbox{correction} of the first and second moment (mean bias and dispersion for Gaussian distributed continuous

Effects of tensor forces in nuclear spin–orbit splittings from ab initio calculations

Directory of Open Access Journals (Sweden)

Shihang Shen

2018-03-01

Full Text Available A systematic and specific pattern due to the effects of the tensor forces is found in the evolution of spin–orbit splittings in neutron drops. This result is obtained from relativistic Brueckner–Hartree–Fock theory using the bare nucleon–nucleon interaction. It forms an important guide for future microscopic derivations of relativistic and nonrelativistic nuclear energy density functionals.

Exploring flavor-dependent long-range forces in long-baseline neutrino oscillation experiments

Science.gov (United States)

Chatterjee, Sabya Sachi; Dasgupta, Arnab; Agarwalla, Sanjib Kumar

2015-12-01

The Standard Model gauge group can be extended with minimal matter content by introducing anomaly free U(1) symmetry, such as L e - L μ or L e - L τ . If the neutral gauge boson corresponding to this abelian symmetry is ultra-light, then it will give rise to flavor-dependent long-range leptonic force, which can have significant impact on neutrino oscillations. For an instance, the electrons inside the Sun can generate a flavor-dependent long-range potential at the Earth surface, which can suppress the ν μ → ν e appearance probability in terrestrial experiments. The sign of this potential is opposite for anti-neutrinos, and affects the oscillations of (anti-)neutrinos in different fashion. This feature invokes fake CP-asymmetry like the SM matter effect and can severely affect the leptonic CP-violation searches in long-baseline experiments. In this paper, we study in detail the possible impacts of these long-range flavor-diagonal neutral current interactions due to L e - L μ symmetry, when (anti-)neutrinos travel from Fermilab to Homestake (1300 km) and CERN to Pyhäsalmi (2290 km) in the context of future high-precision superbeam facilities, DUNE and LBNO respectively. If there is no signal of long-range force, DUNE (LBNO) can place stringent constraint on the effective gauge coupling α eμ < 1.9 × 10-53 (7.8 × 10-54) at 90% C.L., which is almost 30 (70) times better than the existing bound from the Super-Kamiokande experiment. We also observe that if α eμ ≥ 2 × 10-52, the CP-violation discovery reach of these future facilities vanishes completely. The mass hierarchy measurement remains robust in DUNE (LBNO) if α eμ < 5 × 10-52 (10-52).

Functional framework and hardware platform for dependability study in short range wireless embedded systems

NARCIS (Netherlands)

Senouci, B.; Annema, Anne J.; Bentum, Marinus Jan; Kerkhoff, Hans G.

2011-01-01

A new direction in short-range wireless applications has appeared in the form of high-speed data communication devices for distances of a few meters. Behind these embedded applications, a complex Hardware/Software architecture is built. Dependability is one of the major challenges in these systems.

Reintroducing the concept of force into relativity theory

International Nuclear Information System (INIS)

Mahajan, S.; Qadir, A.; Valanju, P.

1979-07-01

It is suggested that re-introducing forces into relativity theory may provide new insights and results. A look at the Kerr-Newmann geometry, and special cases of it, from this viewpoint indicates that there can be a short range repulsion in general. This repulsion suggests that naked singularities may be physically feasible. It is also found that there is a gravito-electric repulsion which would be important to consider in a grand unification scheme of strong, weak and electromagnetic forces. 8 references

Reintroducing the concept of force into relativity theory

Energy Technology Data Exchange (ETDEWEB)

Mahajan, S.; Qadir, A.; Valanju, P.

1979-07-01

It is suggested that re-introducing forces into relativity theory may provide new insights and results. A look at the Kerr-Newmann geometry, and special cases of it, from this viewpoint indicates that there can be a short range repulsion in general. This repulsion suggests that naked singularities may be physically feasible. It is also found that there is a gravito-electric repulsion which would be important to consider in a grand unification scheme of strong, weak and electromagnetic forces. 8 references.

Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy

International Nuclear Information System (INIS)

Berman, G. P.; Doolen, G. D.; Hammel, P. C.; Tsifrinovich, V. I.

2000-01-01

We propose a nuclear-spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids: (a) preparation of the ground state, (b) one- and two-qubit quantum logic gates, and (c) a measurement of the final state. The proposed quantum computer can operate at temperatures up to 1 K. (c) 2000 The American Physical Society

Automobile impact forces on concrete wall panels. Technical report

International Nuclear Information System (INIS)

Chiapetta, R.L.; Pang, E.C.

1982-06-01

The objective of this study was to develop force-time impact signature data for use in the design or evaluation of nuclear power plant structures subject to tornado-borne automotive vehicle impact. The approach was based on the use of analytical vehicle models to calculate imact forces. To assess the significance of vehicle/structure interaction for head-on impact force-histories, a lumped-mass model of a reinforced concrete wall panel was coupled to a one-dimensional vehicle model for numerous panel design configurations within the range of practical interest. Vehicle-structure interaction was found to have relatively little effect on the force histories

Nonequilibrium forces following quenches in active and thermal matter

Science.gov (United States)

Rohwer, Christian M.; Solon, Alexandre; Kardar, Mehran; Krüger, Matthias

2018-03-01

Nonequilibrium systems with conserved quantities like density or momentum are known to exhibit long-ranged correlations. This, in turn, leads to long-ranged fluctuation-induced (Casimir) forces, predicted to arise in a variety of nonequilibrium settings. Here, we study such forces, which arise transiently between parallel plates or compact inclusions in a gas of particles, following a change ("quench") in temperature or activity of the medium. Analytical calculations, as well as numerical simulations of passive or active Brownian particles, indicate two distinct forces: (i) The immediate effect of the quench is adsorption or desorption of particles of the medium to the immersed objects, which in turn initiates a front of relaxing (mean) density. This leads to time-dependent density-induced forces. (ii) A long-term effect of the quench is that density fluctuations are modified, manifested as transient (long-ranged) (pair-)correlations that relax diffusively to their (short-ranged) steady-state limit. As a result, transient fluctuation-induced forces emerge. We discuss the properties of fluctuation-induced and density-induced forces as regards universality, relaxation as a function of time, and scaling with distance between objects. Their distinct signatures allow us to distinguish the two types of forces in simulation data. Our simulations also show that a quench of the effective temperature of an active medium gives rise to qualitatively similar effects to a temperature quench in a passive medium. Based on this insight, we propose several scenarios for the experimental observation of the forces described here.

Revision to dedicated short range communication roadside equipment specification - RSU 4.1.Bench Test Plan.

Science.gov (United States)

2017-04-28

The document describes the overall process for evaluating Dedicated Short Range Communication (DSRC) Roadside Units (RSU) against USDOT RSU Specification 4.1 in preparation for field evaluation. The Test Cases contained in this document only evaluate...

Long-range research plan. FY 1987-FY 1991. Volume 3

International Nuclear Information System (INIS)

1986-08-01

The Long-Range Research Plan (LRRP) was prepared by the Office of Nuclear Regulatory Research (RES) to assist the NRC in coordinating its long-range research planning with the short-range budget cycles. The LRRP lays out programmatic approaches for research to help resolve regulatory issues. The plan will be updated annually. It covers: operating reactor inspection, maintenance, and repair; equipment qualification; seismic research; reactor operations and risk; thermal-hydraulic transients; severe accidents; radiation protection and health effects; and waste management

Long-Range Research Plan, FY 1986-FY 1990. Volume 2

International Nuclear Information System (INIS)

1985-08-01

The Long-Range Research Plan (LRRP) was prepared by the Office of Nuclear Regulatory Research (RES) to assist the NRC in coordinating its long-range research planning with the short-range budget cycles. The LRRP lays out programmatic approaches for research to help resolve regulatory issues. The plan will be updated annually. It covers: operating reactor inspection, maintenance, and repair; equipment qualification; seismic research; reactor operations and risk; thermal-hydraulic transients; severe accidents; radiation protection and health effects; and waste management

Report of a workshop on nuclear forces and nonproliferation Woodrow Wilson international center for scholars, Washington, DC October 28, 2010

Energy Technology Data Exchange (ETDEWEB)

Pilat, Joseph F [Los Alamos National Laboratory

2010-12-08

A workshop sponsored by the Los Alamos National Laboratory in cooperation with the Woodrow Wilson International Center for Scholars was held at the Wilson Center in Washington, DC, on October 28, 2010. The workshop addressed evolving nuclear forces and their impacts on nonproliferation in the context of the new strategic environment, the Obama Administration's Nuclear Posture Review and the 2010 NPT Review Conference. The discussions reflected the importance of the NPR for defining the role of US nuclear forces in dealing with 21st century threats and providing guidance for National Nuclear Security Administration (NNSA) and Department of Defense (DoD) programs and, for many but not all participants, highlighted its role in the successful outcome of the NPT RevCon. There was widespread support for the NPR and its role in developing the foundations for a sustainable nuclear-weapon program that addresses nuclear weapons, infrastructure and expertise in the broader nonproliferation, disarmament and international security contexts. However, some participants raised concerns about its implementation and its long-term effectiveness and sustainability.

Answers to questions posed by the Michigan Governor's Nuclear Waste Disposal Task Force

Energy Technology Data Exchange (ETDEWEB)

1976-09-30

A general presentation of the National Waste Terminal Storage (NWTS) Program was given on July 26, 1976, to the Michigan Environmental Review Board and the Michigan Governor's Nuclear Waste Disposal Task Force. Following the presentation, Dr. William G. Taylor, Chairman of the Task Force, provided ERDA with a listing of questions which pertained to the NWTS program and ERDA/OWI's interest in northeast Michigan. This document contains copies of the information which was provided to Dr. Taylor in response to his inquiry.

Opportunities in Nuclear Science: A Long-Range Plan for the Next Decade

Energy Technology Data Exchange (ETDEWEB)

None, None

2002-04-01

The DOE/NSF Nuclear Science Advisory Committee of the Department of Energy and the National Science Foundation is charged with providing advice on a continuing basis regarding the management of the national basic nuclear science research program. In July 2000, the Committee was asked to study the opportunities and priorities for U.S. nuclear physics research, and to develop a long-range plan that will serve as a frame-work for the coordinated advancement of the field for the next decade. The plan contained here is the fifth that has been pre-pared since the Committee was established. Each of the earlier plans has had substantial impact on new directions and initiatives in the field.

Coulomb corrections to nuclear scattering lengths and effective ranges for weakly bound systems

International Nuclear Information System (INIS)

Mur, V.D.; Popov, V.S.; Sergeev, A.V.

1996-01-01

A procedure is considered for extracting the purely nuclear scattering length as and effective range rs (which correspond to a strong-interaction potential Vs with disregarded Coulomb interaction) from the experimentally determined nuclear quantities acs and rcs, which are modified by Coulomb interaction. The Coulomb renormalization of as and rs is especially strong if the system under study involves a level with energy close to zero (on the nuclear scale). This applies to formulas that determine the Coulomb renormalization of the low-energy parameters of s scattering (l=0). Detailed numerical calculations are performed for coefficients appearing in the equations that determine Coulomb corrections for various models of the potential Vs(r). This makes it possible to draw qualitative conclusions that the dependence of Coulomb corrections on the form of the strong-interaction potential and, in particular, on its small-distance behavior. A considerable enhancement of Coulomb corrections to the effective range rs is found for potentials with a barrier

The American and Russian plans of nuclear disarmament

International Nuclear Information System (INIS)

Gallois, P.

2010-01-01

This text was published in 1991, at the end of the Cold War. The author comments the intentions of the US and Russia leaders, Bush and Gorbachev, on nuclear disarmament and more specifically on limitations and reductions concerning the different nuclear weapons types and vectors (ballistic missiles, submarine launched missiles, Europe-based missiles, nuclear strategic warheads, nuclear weapon movements, short range missiles, cruise missiles). He also evokes the consequences for France of the American propositions

A first-principles study of short range order in Cu-Zn

International Nuclear Information System (INIS)

Slutter, M.; Turchi, P.E.A.; Johnson, D.D.; Nicholson, D.M.; Stocks, G.M.; Pinski, F.J.

1990-01-01

Recently, measurements of short-range order (SRO) diffuse neutron scattering intensity have been performed on quenched Cu-Zn alloys with 22.4 to 31.1 atomic percent (a/o) Zn, and pair interactions were obtained by inverse Monte Carlo simulation. These results are compared to SRO intensities and effective pair interactions obtained from first-principles electronic structure calculations. The theoretical SRO intensities were calculated with the cluster variation method (CVM) in the tetrahedron-octahedron approximation with first-principles pain interactions as input. More generally, phase stability in the Cu-Zn alloy system is discussed, using ab-initio energetic properties

Targeted Identification of Short Interspersed Nuclear Element Families Shows Their Widespread Existence and Extreme Heterogeneity in Plant Genomes[W

Science.gov (United States)

Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

2011-01-01

Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5′ truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3′ end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families. PMID:21908723

Dynamic electrostatic force microscopy technique for the study of electrical properties with improved spatial resolution

International Nuclear Information System (INIS)

Maragliano, C; Heskes, D; Stefancich, M; Chiesa, M; Souier, T

2013-01-01

The need to resolve the electrical properties of confined structures (CNTs, quantum dots, nanorods, etc) is becoming increasingly important in the field of electronic and optoelectronic devices. Here we propose an approach based on amplitude modulated electrostatic force microscopy to obtain measurements at small tip–sample distances, where highly nonlinear forces are present. We discuss how this improves the lateral resolution of the technique and allows probing of the electrical and surface properties. The complete force field at different tip biases is employed to derive the local work function difference. Then, by appropriately biasing the tip–sample system, short-range forces are reconstructed. The short-range component is then separated from the generic tip–sample force in order to recover the pure electrostatic contribution. This data can be employed to derive the tip–sample capacitance curve and the sample dielectric constant. After presenting a theoretical model that justifies the need for probing the electrical properties of the sample in the vicinity of the surface, the methodology is presented in detail and verified experimentally. (paper)

Anomalous X-ray scattering studies of short-, intermediate- and extended-range order in glasses

International Nuclear Information System (INIS)

Price, D.L.; Saboungi, M.L.; Armand, P.; Cox, D.E.

1998-01-01

The authors present the formalism of anomalous x-ray scattering as applied to partial structure analysis of disordered materials, and give an example of how the technique has been applied, together with that of neutron diffraction, to investigate short-, intermediate- and extended-range order in vitreous germania and rubidium germanate

Ultra-short laser pulse ablation using shear-force feedback: Femtosecond laser induced breakdown spectroscopy feasibility study

International Nuclear Information System (INIS)

Samek, Ota; Kurowski, Andre; Kittel, Silke; Kukhlevsky, Sergei; Hergenroeder, Roland

2005-01-01

This work reports on a feasibility study of proximity ablation using femtosecond pulses. Ultra-short pulses were launched to a bare tapered optical fiber and delivered to the sample. The tip-sample distance was controlled by means of shear-force feedback. Consequently, ablation craters with submicrometer dimensions were obtained. Potential analytical applications for Laser Induced Breakdown Spectroscopy (LIBS) technique, such as e.g. inclusions in steel or bio cells, are suggested

Developing role of short-lived radionuclides in nuclear medical practice. DOE symposium series; 56

International Nuclear Information System (INIS)

Paras, P.; Thiessen, J.W.

1985-01-01

The purpose was to define the developing role and state-of-the-art development of short-lived radionuclides (SLR's) in current nuclear medical practice. Special emphasis was placed on radionuclides with general-purpose labeling capabilities. The need for high-purity labeling-grade iodine-123 was emphasized in the program. Papers have been separately abstracted for the data base

Hadronic and nuclear interactions in QCD

International Nuclear Information System (INIS)

1982-01-01

Despite the evidence that QCD - or something close to it - gives a correct description of the structure of hadrons and their interactions, it seems paradoxical that the theory has thus far had very little impact in nuclear physics. One reason for this is that the application of QCD to distances larger than 1 fm involves coherent, non-perturbative dynamics which is beyond present calculational techniques. For example, in QCD the nuclear force can evidently be ascribed to quark interchange and gluon exchange processes. These, however, are as complicated to analyze from a fundamental point of view as is the analogous covalent bond in molecular physics. Since a detailed description of quark-quark interactions and the structure of hadronic wavefunctions is not yet well-understood in QCD, it is evident that a quantitative first-principle description of the nuclear force will require a great deal of theoretical effort. Another reason for the limited impact of QCD in nuclear physics has been the conventional assumption that nuclear interactions can for the most part be analyzed in terms of an effective meson-nucleon field theory or potential model in isolation from the details of short distance quark and gluon structure of hadrons. These lectures, argue that this view is untenable: in fact, there is no correspondence principle which yields traditional nuclear physics as a rigorous large-distance or non-relativistic limit of QCD dynamics. On the other hand, the distinctions between standard nuclear physics dynamics and QCD at nuclear dimensions are extremely interesting and illuminating for both particle and nuclear physics

Theoretical interpretation of high-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1992-06-01

Nuclear collisions are interpreted theoretically. The nuclear equation of state is studied in a wide energy range. Subnucleonic degrees of freedom are invoked at high energy densities and at short length-scales. Questions of dynamical collision simulations are investigated. Direct support is provided for experiment in the form of collaborative projects. The major objective of this nuclear theory program is a better understanding of the properties of strongly interacting matter on the nuclear energy scale, as manifested in high-energy heavy-ion collisions

Control of strength and stability of emulsion-gels by a combination of long- and short-range interactions

NARCIS (Netherlands)

Blijdenstein, T.B.J.; Hendriks, W.P.G.; Linden, van der E.; Vliet, van T.; Aken, van G.A.

2003-01-01

This paper discusses the change in phase behavior and mechanical properties of oil-in-water emulsion gels brought about by variation of long- and short-range attractive interactions. The model system studied consisted of oil droplets stabilized by the protein -lactoglobulin (-lg). A long-range

U.S. Theater Nuclear Policy

International Nuclear Information System (INIS)

Thompson, J.A.

1994-01-01

In the brief period between May 1978 and December 12, 1979, U.S. policy, and the policy of the NATO Alliance, toward theater nuclear forces (TNF) changed dramatically. The consequences of this change now dominate the political agenda in East-West (and West-West) relations. The ultimate outcome of the now renamed intermediate-range nuclear force (INF) debate will have far-reaching consequences for the future of the Atlantic Alliance. How did this issue emerge? Why did the US change its policy? How did it work with its Alliance to change NATO policy? These questions, among others, are now figuring in the debate. The answers to these questions are discussed in detail

Debye sheath mechanism at laser plasma interaction and generalization to nuclear forces and quark-gluon plasma

Science.gov (United States)

Osman, Frederick; Ghahramani, Nader; Hora, Heinrich

2005-10-01

The studies of laser ablation have lead to a new theory of nuclei, endothermic nuclei generation, and quark-gluon plasmas. The surface of ablated plasma expanding into vacuum after high power laser irradiation of targets contains an electric double layer having the thickness of the Debye length. This led to the discovery of surface tension in plasmas, and led to the internal dynamic electric fields in all inhomogeneous plasmas. The surface tension causes stabilization by short length surface wave smoothing the expanding plasma plume and to stabilization against the Rayleigh Taylor instability. Generalizing this to the degenerate electrons in a metal with the Fermi energy instead of the temperature resulted in the first quantum theory of surface tension of metals in agreement with measurements. Taking the Fermi energy in the Debye length for nucleons results in a theory of nuclei with stable confinement of protons and neutrons just at the well-known nuclear density, and the Debye lengths equal to the Hofstadter decay of the nuclear surface. Increasing the nuclear density by a factor of 10 leads to a change of the Fermi energy into its relativistic branch where no surface energy is possible and the particle mass is not defined, permitting the quark gluon plasma. Expansion of this higher density at the big bang or in super-nova results in nucleation and element generation. The Boltzmann equilibrium permits the synthesis of nuclei even in the endothermic range, however with the limit to about uranium. A relation for the magic numbers leads to a quark structure of nuclear shells that can be understood as a duality property of nuclei with respect to nucleons and quarks

Short-range structure and thermal properties of barium tellurite glasses

Science.gov (United States)

Kaur, Amarjot; Khanna, Atul; Gonzàlez, Fernando

2017-05-01

BaO-TeO2 glasses containing 10 to 20 BaO mol% were prepared and characterized by X-ray diffraction, density measurements, differential scanning calorimetry and Raman spectroscopy. Glass density decreases with increase in BaO concentration from 10 to 20 mol%, due to replacement of heavier TeO2 by lighter BaO, however glass transition temperature (Tg) increases significantly from a value of 318°C to 327°C due to increase in average single bond enthalpy of the tellurite network. Raman studies found that glass short-range structure consists of TeO4 and TeO3 structural units and BaO modifies the network by producing the structural transformation: TeO4→ TeO3.

Three-Nucleon Forces and Triplet Pairing in Neutron Matter

Science.gov (United States)

Papakonstantinou, P.; Clark, J. W.

2017-12-01

The existence of superfluidity of the neutron component in the core of a neutron star, associated specifically with triplet P-wave pairing, is currently an open question that is central to interpretation of the observed cooling curves and other neutron-star observables. Ab initio theoretical calculations aimed at resolving this issue face unique challenges in the relevant high-density domain, which reaches beyond the saturation density of symmetrical nuclear matter. These issues include uncertainties in the three-nucleon (3N) interaction and in the effects of strong short-range correlations—and more generally of in-medium modification of nucleonic self-energies and interactions. A survey of existing solutions of the gap equations in the triplet channel demonstrates that the net impact on the gap magnitude of 3N forces, coupled channels, and mass renormalization shows extreme variation dependent on specific theoretical inputs, in some cases even pointing to the absence of a triplet gap, thus motivating a detailed analysis of competing effects within a well-controlled model. In the present study, we track the effects of the 3N force and in-medium modifications in the representative case of the ^3P_2 channel, based on the Argonne v_{18} two-nucleon (2N) interaction supplemented by 3N interactions of the Urbana IX family. Sensitivity of the results to the input interaction is clearly demonstrated. We point out consistency issues with respect to the simultaneous treatment of 3N forces and in-medium effects, which warrant further investigation. We consider this pilot study as the first step toward a systematic and comprehensive exploration of coupled-channel ^3P F_2 pairing using a broad range of 2N and 3N interactions from the current generation of refined semi-phenomenological models and models derived from chiral effective field theory.