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Sample records for exclusive hard diffraction

  1. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

  2. Diffractive and exclusive measurements at CDF

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2006-06-01

    Experimental results from the CDF experiment at the Tevatron in p{bar p} collisions at {radical}s = 1.96 TeV are presented on the diffractive structure function at different values of the exchanged momentum transfer squared in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, on the four-momentum transfer |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}, and on the first experimental evidence of exclusive production in both dijet and diphoton events. A novel technique to align the Roman Pot detectors is also presented.

  3. CMS results on exclusive and diffractive production

    SciTech Connect

    Alves, Gilvan A.

    2015-04-10

    We present recent CMS measurements of diffractive and exclusive processes, using data collected at 7 TeV at the LHC. Measurements of soft single- and double-diffractive cross sections are presented, as well as measurements of photon-induced processes including studies of exclusive WW production via photon-photon exchange.

  4. Diffraction and central exclusive production at ATLAS

    SciTech Connect

    Tasevsky, Marek

    2011-07-15

    The diffractive physics program for the ATLAS experiment with an emphasis on the central exclusive production is discussed. The key point in this discussion is the need for an unambiguous experimental definition of diffractive signature which would be acceptable and reproducible by theorists. Recent ATLAS results from samples enhanced in diffraction contribution underline this need.

  5. Hard diffractive results and prospects at the Tevatron

    SciTech Connect

    Peters, Krisztian; /Manchester U.

    2006-01-01

    We review hard diffractive results and prospects at the Tevatron with an emphasis on factorization breaking in diffractive processes. Upper limits on the exclusive di-jet and {chi}{sub c}{sup 0} production cross sections at CDF and the status of the D0 Forward Proton Detectors are discussed.

  6. Exclusive diffractive electroproduction of dijets in collinear factorization

    SciTech Connect

    Braun, V.M.; Ivanov, D.Yu.

    2005-08-01

    Exclusive electroproduction of hard dijets can be described within the collinear factorization. This process has clear experimental signature and provides one with an interesting alternative venue to test QCD description of hard diffractive processes and extract information on generalized nucleon parton distributions. In this work we present detailed leading-order QCD calculations of the relevant cross sections, including longitudinal momentum fraction distribution of the dijets and their azimuthal angle dependence.

  7. Hard Exclusive Reactions at Jlab

    SciTech Connect

    Kubarovsky, Valery P.

    2011-09-20

    Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) have been carried out at Jefferson Lab. DVCS helicity--dependent and helicity--independent cross sections and beam spin asymmetries have been measured, as well as cross sections and asymmetries for the $\\pi^0$, $\\eta$, $\\rho^0$, $\\rho^+$, $\\omega$ and $\\phi$ for exclusive electroproduction. The data were taken in a wide kinematic range in $Q^2$=1--4.5 GeV$^2$, $x_B$=0.1--0.5, and $|t|$ up to 2 GeV$^2$. The presented results offer a unique opportunity to study the structure of the nucleon at the parton level as one has access to Bjorken $x_B$ and momentum transfer to the nucleon $t$ at the same time.

  8. Hard Exclusive Vector Meson Leptoproduction At HERMES

    SciTech Connect

    Golembiovskaya, M.

    2011-07-15

    The HERMES experiment at DESY, Hamburg collected a set of data on hard exclusive vector meson ({rho}{sup 0}{phi},{omega}) leptoproduction using the 27.6 GeV longitudinally polarized lepton beam of HERA accelerator and longitudinally or transversely polarized or unpolarized gas targets. Measurements of exclusive vector meson production provide access to the structure of the nucleon since the process can be described in terms of Generalized Parton Distributions (GPDs). An overview of the HERMES results on exclusive vector mesons production is presented.

  9. Hard diffraction and rapidity gaps

    SciTech Connect

    Albrow, M.G.

    1994-08-01

    I describe the evolution of experiments at hadron colliders on (a) high mass diffraction (b) double pomeron exchange, from the ISR through the Sp{bar p}S to the Tevatron. I emphasize an experimental approach to the question: ``What is the pomeron?``

  10. CMS results on soft and hard diffraction

    NASA Astrophysics Data System (ADS)

    Obertino, M. M.

    2017-03-01

    The measurement of the soft diffractive cross sections in single- and double-diffractive final states is presented at 7 TeV. Furthermore, the production of jet-gap-jet final states is discussed and the results are interpreted in terms of a hard color singlet exchange. Finally, general features of particle production in single-diffractive enhanced events are shown at 13 TeV.

  11. Novel Aspects of Hard Diffraction in QCD

    SciTech Connect

    Brodsky, Stanley J.; /SLAC

    2005-12-14

    Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, and nuclear shadowing and antishadowing--leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also discuss the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency.

  12. QCD mechanism of hard diffractive dissociation

    SciTech Connect

    Mironov, A.D.; Roizen, I.I.

    1988-04-01

    Various types of hard double diffractive dissociation (DDD) processes at high energy are analyzed within the framework of QCD. The relation between the QCD description and the Regge phenomenology is discussed and the region of validity is estimated for each approach.

  13. QCD and hard diffraction at the LHC

    SciTech Connect

    Albrow, Michael G.; /Fermilab

    2005-09-01

    As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

  14. Hard Exclusive Meson Production at COMPASS

    NASA Astrophysics Data System (ADS)

    Ter Wolbeek, Johannes

    2016-02-01

    The concept of Generalized Parton Distributions (GPDs) combines two-dimensional spatial information given by form factors, with longitudinal momentum information from Parton Distribution Functions. GPDs provide comprehensive description of the nucleon structure involving a wealth of new information. For instance, according to Ji’s sum rule, the GPDs H and E enable access to the total angular momenta of quarks, antiquarks and gluons. While H can be approached using measurements of electroproduction cross sections, asymmetry measurements in hard exclusive meson production off transversely polarized targets can help to constrain the GPD E and chiral-odd GPDs. In 2007 and 2010 the COMPASS experiment at CERN collected data by scattering a 160GeV/c muon beam off a transversely polarized NH3 target. Exclusive vector-meson production μ + p → μ‧ + p + V with a ρ0 or ω meson in the final state is studied and five single-spin and three double-spin azimuthal asymmetries are measured.

  15. Measurements of diffractive and exclusive processes with ATLAS

    NASA Astrophysics Data System (ADS)

    Dyndal, Mateusz

    2017-03-01

    The ATLAS collaboration has carried out a range of measurements related with diffractive and exclusive processes. In the absence of forward proton tagging, these processes can be distinguished in the central part of the ATLAS detector exploiting the large rapidity gap in the central region and the absence of charged particles reconstructed in the inner tracking detector. This strategy has been applied to study the exclusive production of lepton pairs and the diffractive dijet production.

  16. Impact factor for exclusive diffractive dijet production with NLO accuracy

    NASA Astrophysics Data System (ADS)

    Boussarie, R.; Grabovsky, A. V.; Szymanowski, L.; Wallon, S.

    2017-03-01

    Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results.

  17. Generalized parton distributions and rapidity gap survival in exclusive diffractive pp scattering

    SciTech Connect

    Frankfurt, L.; Hyde, C. E.; Strikman, M.; Weiss, C.

    2007-03-01

    We study rapidity gap survival (RGS) in the production of high-mass systems (H=dijet, heavy quarkonium, Higgs boson) in double-gap exclusive diffractive pp scattering, pp{yields}p+(gap)+H+(gap)+p. Our approach is based on the idea that hard and soft interactions are approximately independent because they proceed over widely different time and distance scales. We implement this idea in a partonic description of proton structure, which allows for a model-independent treatment of the interplay of hard and soft interactions. The high-mass system is produced in a hard scattering process with exchange of two gluons between the protons, whose amplitude is calculable in terms of the gluon generalized parton distribution (GPD), measured in exclusive ep scattering. The hard scattering process is modified by soft spectator interactions, which we calculate neglecting correlations between hard and soft interactions (independent interaction approximation). We obtain an analytic expression for the RGS probability in terms of the phenomenological pp elastic scattering amplitude, without reference to the eikonal approximation. Contributions from inelastic intermediate states are suppressed. The onset of the black-disk limit in pp scattering at TeV energies strongly suppresses diffraction at small impact parameters and is the main factor in determining the RGS probability. Correlations between hard and soft interactions (e.g. due to scattering from the long-range pion field of the proton or due to possible short-range transverse correlations between partons) further decrease the RGS probability. We also investigate the dependence of the diffractive cross section on the transverse momenta of the final-state protons ('diffraction pattern'). By measuring this dependence one can perform detailed tests of the interplay of hard and soft interactions and even extract information about the gluon GPD in the proton. Such studies appear to be feasible with the planned forward detectors at the

  18. Diffraction by a Hard Half-Plane Useful Approximations to AN Exact Formulation

    NASA Astrophysics Data System (ADS)

    OUIS, D.

    2002-04-01

    In this paper, the problem of diffraction of a spherical wave by a hard half-plane is considered. The starting point is the Biot-Tolstoy theory of diffraction of a spherical wave by a fluid wedge with hard boundaries. In this theory, the field at a point in the fluid is composed eventually of a geometrical part: i.e., a direct component, one or two components due to the reflections on the sides of the hard wedge, and a diffracted component due exclusively to the presence of the edge of the wedge. The mathematical expression of this latter component has originally been given in an explicit closed form for the case of a unit momentum wave incidence, but Medwin has further developed its expression for the more useful case of a Dirac delta point excitation. The expression of this form is given in the time domain, but it is quite difficult to find exactly its Fourier transform for studying the frequency behaviour of the diffracted field. It is thus the aim of this paper to present various useful approximations of the exact expression. Among the approximations treated, three are most accurate for engineering purposes, and one of them is proposed, for its simplicity, as appropriate for most occurring practical situations.

  19. Exclusive central diffractive production of scalar, pseudoscalar and vector mesons

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, P.; Nachtmann, O.; Szczurek, A.

    2014-11-01

    We discuss exclusive central diffractive production of scalar (ƒ0(980), ƒ0(1370), ƒ0(1500)), pseudoscalar (η, η'(958)), and vector (ρ0) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the ƒ0(980) and η production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the ρ0 production the photon-pomeron and pomeron-photon exchanges are considered. The coupling parameters of tensor pomeron and/or reggeon are fixed from the H1 and ZEUS experimental data of the γp → ρ0 p reaction. We present first predictions of this mechanism for pp → ppπ+π- reaction being studied at COMPASS, RHIC, Tevatron, and LHC. Correlation in azimuthal angle between outgoing protons and distribution in pion rapidities at √s = 7 TeV are presented. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron.

  20. Hard single diffractive jet production at D0

    SciTech Connect

    Abachi, S.; Abbott, B.; Abolins, M.; D0 Collaboration

    1996-08-01

    Preliminary results from the D{null} experiment on jet production with forward rapidity gaps in {ital p{anti p}} collisions are presented. A class of dijet events with a forward rapidity gap is observed at center-of-mass energies {radical}s = 1800 GeV and 630 GeV. The number of events with rapidity gaps at both center-of-mass energies is significantly greater than the expectation from multiplicity fluctuations and is consistent with a hard single diffractive process. A small class of events with two forward gaps and central dijets is also observed at 1800 GeV. This topology is consistent with hard double pomeron exchange.

  1. Diffractive W/Z and exclusive dijet production at CDF II

    SciTech Connect

    Goulianos, Konstantin; /Rockefeller U.

    2008-04-01

    We report preliminary single-diffractive W/Z and final exclusive dijet production results for {bar p}p collisions at {radical}s = 1.96 TeV extracted from data collected by the CDF II detector at the Fermilab Tevatron. The results are compared with previous measurements, and the obtained exclusive dijet cross sections are used to constrain/calibrate theoretical models for exclusive Higgs boson production rates at the Large Hadron Collider.

  2. Incoherent Diffractive Imaging via Intensity Correlations of Hard X Rays

    NASA Astrophysics Data System (ADS)

    Classen, Anton; Ayyer, Kartik; Chapman, Henry N.; Röhlsberger, Ralf; von Zanthier, Joachim

    2017-08-01

    Established x-ray diffraction methods allow for high-resolution structure determination of crystals, crystallized protein structures, or even single molecules. While these techniques rely on coherent scattering, incoherent processes like fluorescence emission—often the predominant scattering mechanism—are generally considered detrimental for imaging applications. Here, we show that intensity correlations of incoherently scattered x-ray radiation can be used to image the full 3D arrangement of the scattering atoms with significantly higher resolution compared to conventional coherent diffraction imaging and crystallography, including additional three-dimensional information in Fourier space for a single sample orientation. We present a number of properties of incoherent diffractive imaging that are conceptually superior to those of coherent methods.

  3. The Use of Hard Synchrotron Radiation for Diffraction Studies of Composite and Functional Materials

    NASA Astrophysics Data System (ADS)

    Ancharov, A. I.

    2017-07-01

    Potential use of hard synchrotron radiation (SR) with the quantum energy above 25 keV is discussed aiming to solve a number of research tasks on investigation of structural changes taking place in materials. The advantages and limitations of the use of hard SR for diffraction studies are evaluated. A review of the principal techniques is made wherein application of hard SR both promotes certain experimental investigations and frequently allows obtaining new structural data unavailable with X-ray tubes.

  4. Sound Scattering by a Hard Half-Plane Experimental Evidence of the Edge-Diffracted Wave

    NASA Astrophysics Data System (ADS)

    OUIS, D.

    2002-05-01

    In this short note, some experimental results are presented on the diffraction of a spherical way by a hard half-plane. This study was conducted with the aim to give evidence to the existence of the edge-diffracted wave. The sound source used in this experimental study is a condenser microphone operating in a reverse way. The wave emitted by a sound source propagates in space and hits a thin aluminium sheet with a straight edge, considered as an idealization of the hard half-plane. The resulting impulse response includes among others a wave diffracted by the edge of the half-plane, which is compared to its theoretical prediction. This latter is calculated from the exact Biot and Tolstoy solution to the problem of diffraction of a spherical wave by a hard wedge. Relatively satisfactory agreement is found between theory and experiment.

  5. Measurement of exclusive dijet production in diffractive DIS with the ZEUS detector at HERA

    SciTech Connect

    Gach, Grzegorz

    2015-04-10

    The exclusive production of dijets in diffractive deep inelastic lepton–proton scattering has been measured with the ZEUS detector at HERA with an integrated luminosity of 372 pb{sup −1}. Jets have been reconstructed in the photon–Pomeron rest frame using the exclusive k{sub T} algorithm. The shape of the differential cross-section as a function of the angle between the plane spanned by the incoming and scattered lepton momenta and the plane spanned by the virtual photon and jets momenta is presented. The shape is determined by the jet production mechanism and provides information about the Pomeron structure.

  6. Measurement of exclusive dijet production in diffractive DIS with the ZEUS detector at HERA

    NASA Astrophysics Data System (ADS)

    Gach, Grzegorz

    2015-04-01

    The exclusive production of dijets in diffractive deep inelastic lepton-proton scattering has been measured with the ZEUS detector at HERA with an integrated luminosity of 372 pb-1. Jets have been reconstructed in the photon-Pomeron rest frame using the exclusive kT algorithm. The shape of the differential cross-section as a function of the angle between the plane spanned by the incoming and scattered lepton momenta and the plane spanned by the virtual photon and jets momenta is presented. The shape is determined by the jet production mechanism and provides information about the Pomeron structure.

  7. Crystal cavity resonance for hard x rays: A diffraction experiment

    SciTech Connect

    Chang, S.-L.; Stetsko, Yu. P.; Tang, M.-T.; Shew, B.-Y.; Lee, Y.-R.; Sun, W.-H.; Wu, H.-H.; Kuo, T.-T.; Chen, S.-Y.; Chang, Y.-Y.; Shy, J.-T.; Yabashi, M.; Tamasaku, K.; Miwa, D.

    2006-10-01

    We report the details of the recent x-ray back diffraction experiments, in which interference fringes due to x-ray cavity resonance are unambiguously observed. The Fabry-Perot type cavities, the tested crystal devices of reflectivity R{approx_equal}0.5 and finesse F{approx_equal}2.3, consist of monolithic two-plate and eight-plate silicon crystals. They were prepared by using x-ray lithographic techniques. The thicknesses of the crystal plates and the gaps between the two adjacent plates are a few tens to hundreds {mu}m. The (12 4 0) back reflection and synchrotron x-radiation of energy resolution {delta}E=0.36 meV at 14.4388 keV are employed. Interference fringes in angle- and photon-energy scans for two-plate and eight-plate cavities are shown. Considerations on the temporal and spatial coherence for observable resonance interference fringes using synchrotron x-rays are presented. The details about the accompanied simultaneous 24-beam diffraction in relation to x-ray photon energy are also described.

  8. Photoproduction of J/ψ and ϒ in exclusive and proton dissociative diffractive events

    NASA Astrophysics Data System (ADS)

    Schäfer, Wolfgang; Cisek, Anna; Szczurek, Antoni

    2016-11-01

    We use a perturbative QCD based kT -factorization approach, to calculate the amplitude for the diffractive γp → Vp processes, where V is a J/ψ or ϒ ground state or excited vector meson. Using these amplitudes, we evaluate the cross section for exclusive photoproduction of J/ψ, ψ', ϒ mesons in proton-proton collisions. Calculations are performed for a variety of unintegrated gluon distributions, and we compare our results to LHCb data. Absorption effects are taken into account at the amplitude level. We also discuss the related diffractive production in proton dissociative events. Here we concentrate on electromagnetic dissociation , which is calculable without additional free parameters. Besides being of interest in their own right, dissociative events constitute an important experimental background to exclusive production.

  9. Coherent Diffraction Imaging with Hard X-Ray Waveguides

    NASA Astrophysics Data System (ADS)

    Caro, Liberato De; Giannini, Cinzia; Pelliccia, Daniele; Cedola, Alessia; Lagomarsino, Stefano

    2013-01-01

    Coherent X-ray diffraction imaging (CXDI) has been widely applied in the nanoscopic world, offering nanometric-scale imaging of noncrystallographic samples, and permitting the next-generation structural studies on living cells, single virus particles and biomolecules. The use of curved wavefronts in CXDI has caused a tidal wave in the already promising application of this emergent technique. The non-planarity of the wavefront allows to accelerate any iterative phase-retrieval process and to guarantee a reliable and unique solution. Nowadays, successful experiments have been performed with Fresnel zone plates and planar waveguides as optical elements. Here we describe the use of a single planar waveguide as well as two crossed waveguides in the experiments which first showed this optical element a promising tool for producing a line- or point-like coherent source, respectively.

  10. Production of exclusive dijets in diffractive deep inelastic scattering at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Aushev, Y.; Behnke, O.; Behrens, U.; Bertolin, A.; Bloch, I.; Boos, E. G.; Borras, K.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Dusini, S.; Figiel, J.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, M.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Makarenko, I.; Malka, J.; Mergelmeyer, S.; Mohamad Idris, F.; Mohammad Nasir, N.; Myronenko, V.; Nagano, K.; Nobe, T.; Notz, D.; Nowak, R. J.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Pokrovskiy, N. S.; Przybycień, M.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Shyrma, Yu.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2016-01-01

    Production of exclusive dijets in diffractive deep inelastic e^± p scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb^{-1}. The measurement was performed for γ ^{*}- p centre-of-mass energies in the range 90< W < {250} {GeV} and for photon virtualities Q^2 > {25} {GeV2}. Energy flows around the jet axis are presented. The cross section is presented as a function of β and φ , where β =x/x_IP, x is the Bjorken variable and x_IP is the proton fractional longitudinal momentum loss. The angle φ is defined by the γ ^{*}-dijet plane and the γ ^{*}-e^± plane in the rest frame of the diffractive final state. The φ cross section is measured in bins of β . The results are compared to predictions from models based on different assumptions about the nature of the diffractive exchange.

  11. Coherent diffraction imaging using focused hard X-rays

    NASA Astrophysics Data System (ADS)

    Kim, Sunam; Kim, Sangsoo; Lee, Su Yong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Marathe, Shashidhara; Song, Changyong; Gallagher-Jones, Marcus; Kang, Hyon Chol

    2016-05-01

    A quantitative height profile image of a silicon nano-trench structure was obtained via coherent diffraction imaging (CDI) utilizing focused X-rays at a photon energy of 5.5 keV. The ability to optimize the spatial coherence and the photon flux density of a focused X-ray beam was the key technique for achieving such technical progress at a given X-ray photon flux. This was achieved by investigating the tunability of the focused beam's optical properties and performing a CDI experiment with the focused X-rays. The relationship between the focused X-rays' optical properties ( e.g., photon flux density and spatial coherence length) and the incident beam's size, which can be tuned by adjusting the slits in front of the Fresnel zone plate (FZP) was elucidated. We also obtained a quantitative image of a nano-trench sample produced via the reconstruction process of CDI, which utilizes carefully tuned, focused X-rays.

  12. On the constituent counting rule for hard exclusive processes involving multi-quark states

    NASA Astrophysics Data System (ADS)

    Guo, Feng-Kun; Meißner, Ulf-G.; Wang, Wei

    2017-05-01

    At high energy, the cross section at finite scattering angle of a hard exclusive process falls off as a power of the Manderstam variable s. If all involved quark-gluon compositions undergo hard momentum transfers, the fall-off scaling is determined by the underlying valence structures of the initial and final hadrons, known as the constituent counting rule. In spite of the complication due to helicity conservation, it has been argued that when applied to exclusive process with exotic multiquark states, the counting rule is a powerful way to determine the valence degrees of freedom inside hadron exotics. In this work, we demonstrate that for hadrons with hidden flavors, the naive application of the constituent counting rule to exclusive process with hadron exotic multiquark states is problematic, since it is not mandatory for all components to participate in hard scattering at the scale . We illustrate the problems in the viewpoint based on effective field theory. We clarify the misleading results that may be obtained from the constituent counting rule in exclusive processes with exotic candidates such as , , X(3872), etc. Supported in part by DFG and NSFC through funds provided to the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD” (NSFC Grant No. 11261130311), Thousand Talents Plan for Young Professionals, Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) (2015VMA076), National Natural Science Foundation of China (11575110, 11655002), Natural Science Foundation of Shanghai (15DZ2272100, 15ZR1423100), Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF111CJ1), and by Key Laboratory for Particle Physics, Astrophysics and Cosmology, Ministry of Education.

  13. Hard X-ray imaging of bacterial cells: nano-diffraction and ptychographic reconstruction.

    PubMed

    Wilke, R N; Priebe, M; Bartels, M; Giewekemeyer, K; Diaz, A; Karvinen, P; Salditt, T

    2012-08-13

    Ptychographic coherent X-ray diffractive imaging (PCDI) has been combined with nano-focus X-ray diffraction to study the structure and density distribution of unstained and unsliced bacterial cells, using a hard X-ray beam of 6.2keV photon energy, focused to about 90nm by a Fresnel zone plate lens. While PCDI provides images of the bacteria with quantitative contrast in real space with a resolution well below the beam size at the sample, spatially resolved small angle X-ray scattering using the same Fresnel zone plate (cellular nano-diffraction) provides structural information at highest resolution in reciprocal space up to 2nm(-1). We show how the real and reciprocal space approach can be used synergistically on the same sample and with the same setup. In addition, we present 3D hard X-ray imaging of unstained bacterial cells by a combination of ptychography and tomography.

  14. Studies of semi-inclusive and hard exclusive processes at Jlab

    SciTech Connect

    Harutyun Avagyan

    2008-06-19

    The main goal of experiments proposed for the {\\tt CLAS12} detector in conjunction with the 12-GeV CEBAF accelerator is the study of the nucleon through hard exclusive, semi-inclusive, and inclusive processes. This will provide new insights into nucleon dynamics at the elementary quark and gluon level. In this contribution we provide an overview of ongoing studies of the structure of nucleon in terms of quark and gluon degrees of freedom and future physics program planned with CLAS and {\\tt CLAS12}.

  15. Femtosecond powder diffraction with a laser-driven hard X-ray source.

    PubMed

    Zamponi, F; Ansari, Z; Woerner, M; Elsaesser, T

    2010-01-18

    X-ray powder diffraction with a femtosecond time resolution is introduced to map ultrafast structural dynamics of polycrystalline condensed matter. Our pump-probe approach is based on photoexcitation of a powder sample with a femtosecond optical pulse and probing changes of its structure by diffracting a hard X-ray pulse generated in a laser-driven plasma source. We discuss the key aspects of this scheme including an analysis of detection sensitivity and angular resolution. Applying this technique to the prototype molecular material ammonium sulfate, up to 20 powder diffraction rings are recorded simultaneously with a time resolution of 100 fs. We describe how to derive transient charge density maps of the material from the extensive set of diffraction data in a quantitative way.

  16. Hard X-ray nanoimaging method using local diffraction from metal wire

    SciTech Connect

    Takano, Hidekazu Konishi, Shigeki; Shimomura, Sho; Azuma, Hiroaki; Tsusaka, Yoshiyuki; Kagoshima, Yasushi

    2014-01-13

    A simple hard X-ray imaging method achieving a high spatial resolution is proposed. Images are obtained by scanning a metal wire through the wave field to be measured and rotating the sample to collect data for back projection calculations; the local diffraction occurring at the edges of the metal wire operates as a narrow line probe. In-line holograms of a test sample were obtained with a spatial resolution of better than 100 nm. The potential high spatial resolution of this method is shown by calculations using diffraction theory.

  17. Exclusive diffractive production of π+π- continuum and resonances within tensor pomeron approach

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

    2016-11-01

    We discuss exclusive central diffractive dipion production in proton-(anti)proton collisions at high energies. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an effective field-theoretic approach. We include the purely diffractive dipion continuum, and the scalar and tensor resonances decaying into the π+π- pairs as well as the photoproduction contributions (ρ0, Drell-Söding). We discuss how two pomerons couple to tensor meson f2(1270) and the interference effects of resonance and dipion continuum. The theoretical results are compared with CDF and CMS experimental data. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles. We find that the relative contribution of resonant f2(1270) and dipion continuum strongly depends on the cut on proton transverse momenta (or four-momentum transfer squared t1,2) which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a ππ resonance filter. We suggest some experimental analyses to fix model parameters related to the pomeron-pomeron-meson coupling.

  18. Exclusive central diffractive production of scalar and pseudoscalar mesons; tensorial vs. vectorial pomeron

    SciTech Connect

    Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

    2014-05-15

    We discuss consequences of the models of “tensorial pomeron” and “vectorial pomeron” for exclusive diffractive production of scalar and pseudoscalar mesons in proton–proton collisions. Diffractive production of f{sub 0}(980), f{sub 0}(1370), f{sub 0}(1500), η, and η{sup ′}(958) mesons is discussed. Different pomeron–pomeron–meson tensorial coupling structures are possible in general. In most cases two lowest orbital angular momentum–spin couplings are necessary to describe experimental differential distributions. For f{sub 0}(980) and η production reggeon–pomeron, pomeron–reggeon, and reggeon–reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data. Correlations in azimuthal angle between outgoing protons, distributions in rapidities and transverse momenta of outgoing protons and mesons, in a special “glueball filter variable”, as well as some two-dimensional distributions are presented. We discuss differences between results of the vectorial and tensorial pomeron models. We show that high-energy central production, in particular of pseudoscalar mesons, could provide crucial information on the spin structure of the soft pomeron.

  19. Diffractive imaging at large Fresnel number: Challenge of dynamic mesoscale imaging with hard x rays

    NASA Astrophysics Data System (ADS)

    Barber, John L.; Barnes, Cris W.; Sandberg, Richard L.; Sheffield, Richard L.

    2014-05-01

    Real materials have structure at both the atomic or crystalline scale as well as at interfaces and defects at the larger scale of grains. There is a need for the study of materials at the "mesoscale," the scale at which subgranular physical processes and intergranular organization couple to determine microstructure, crucially impacting constitutive response at the engineering macroscale. Diffractive imaging using photons that can penetrate multiple grains of material would be a transformative technique for the study of the performance of materials in dynamic extremes. Thicker samples imply higher energy photons of shorter wavelength, and imaging of multiple grains implies bigger spot sizes. Such imaging requires the use of future planned and proposed hard x-ray free electron lasers (such as the European XFEL) to provide both the spatial coherence transverse to the large spots and the peak brilliance to provide the short illumination times. The result is that the Fresnel number of the system becomes large and is no longer in the Fraunhofer far-field limit. The interrelated issues of diffractive imaging at large Fresnel number are analyzed, including proof that diffractive imaging is possible in this limit and estimates of the signal-to-noise possible. In addition, derivation of the heating rates for brilliant pulses of x rays are presented. The potential and limitations on multiple dynamic images are derived. This paper will present a study of x-ray interactions with materials in this new regime of spatially coherent but relatively large mesoscale spots at very hard energies. It should provide the theory and design background for the experiments and facilities required to control materials in extreme environments, in particular for the next generation of very-hard-x-ray free electron lasers.

  20. Coherent hard x-ray diffractive imaging of nonisolated objects confined by an aperture

    SciTech Connect

    Kim, Sunam; Kim, Chan; Lee, Suyong; Marathe, Shashidhara; Noh, D. Y.; Kang, H. C.; Kim, S. S.; Sandy, A.; Narayanan, S.

    2010-04-15

    Coherent hard x-ray imaging of nonisolated weak phase objects is demonstrated by confining x-ray beam in a region of a few micrometers in cross section using a micrometer-sized aperture. Two major obstacles in the hard x-ray coherent diffraction imaging, isolating samples and obtaining central speckles, are addressed by using the aperture. The usefulness of the proposed method is illustrated by reconstructing the exit wave field of a nanoscale trench structure fabricated on silicon which serves as a weak phase object. The quantitative phase information of the exit wave field was used to reconstruct the depth profile of the trench structure. The scanning capability of this method was also briefly discussed.

  1. Crystallization and diffraction analysis of the serpin IRS-2 from the hard tick Ixodes ricinus.

    PubMed

    Kovářová, Zuzana; Chmelař, Jindřich; Sanda, Miloslav; Brynda, Jiří; Mareš, Michael; Rezáčová, Pavlína

    2010-11-01

    IRS-2 from the hard tick Ixodes ricinus belongs to the serpin family of protease inhibitors. It is produced in the salivary glands of the tick and its anti-inflammatory activity suggests that it plays a role in parasite-host interaction. Recombinant IRS-2 prepared by heterologous expression in a bacterial system was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the primitive tetragonal space group P4(3) and diffracted to 1.8 Å resolution. Mass-spectrometric and electrophoretic analyses revealed that IRS-2 was cleaved by contaminating proteases during crystallization. This processing of IRS-2 mimicked the specific cleavage of the serpin by its target protease and resulted in a more stable form (the so-called relaxed conformation), which produced well diffracting crystals. Activity profiling with specific substrates and inhibitors demonstrated traces of serine and cysteine proteases in the protein stock solution.

  2. Beyond hard x-ray photoelectron spectroscopy: Simultaneous combination with x-ray diffraction

    SciTech Connect

    Rubio-Zuazo, Juan; Castro, German R.

    2013-05-15

    Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful and novel emerging technique for the nondestructive determination of electronic properties and chemical composition of bulk, buried interfaces and surfaces. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons, increasing the information depth up to several tens of nanometers. Complementing HAXPES with an atomic structure sensitive technique (such as x-ray diffraction) opens a new research field with major applications for materials science. At SpLine, the Spanish CRG beamline at the European Synchrotron Radiation Facility, we have developed a novel experimental set-up that combines HAXPES and x-ray diffraction (x-ray reflectivity, surface x-ray diffraction, grazing incidence x-ray diffraction, and reciprocal space maps). Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a robust 2S + 3D diffractometer hosting a ultrahigh vacuum chamber equipped with a unique photoelectron spectrometer (few eV < electron kinetic energy < 15 keV), x-ray tube (Mg/Ti), 15 keV electron gun, and auxiliary standard surface facilities (molecular beam epitaxy evaporator, ion gun, low energy electron diffraction, sample heating/cooling system, leak valves, load-lock sample transfer, etc.). This end-station offers the unique possibility of performing simultaneous HAXPES + x-ray diffraction studies. In the present work, we describe the experimental set-up together with two experimental examples that emphasize its outstanding capabilities: (i) nondestructive characterization of the Si/Ge and HfO{sub 2}/SiO{sub 2} interfaces on Ge-based CMOS devices, and (ii) strain study on La{sub 0.7}Ca{sub 0.3}MnO{sub 3} ultrathin films grown on SrTiO{sub 3}(001) substrate.

  3. STRAIN CORRELATIONS IN ALLOY 690 MATERIALS USING ELECTRON BACKSCATTER DIFFRACTION AND VICKERS HARDNESS

    SciTech Connect

    Overman, Nicole R.; Toloczko, Mychailo B.; Olszta, Matthew J.; Bruemmer, Stephen M.

    2014-03-09

    High chromium, nickel-base Alloy 690 exhibits an increased resistance to stress corrosion cracking (SCC) in pressurized water reactor (PWR) primary water environments over lower chromium alloy 600. As a result, Alloy 690 has been used to replace Alloy 600 for steam generator tubing, reactor pressure vessel nozzles and other pressure boundary components. However, recent laboratory crack-growth testing has revealed that heavily cold-worked Alloy 690 materials can become susceptible to SCC. To evaluate reasons for this increased SCC susceptibility, detailed characterizations have been performed on as-received and cold-worked Alloy 690 materials using electron backscatter diffraction (EBSD) and Vickers hardness measurements. Examinations were performed on cross sections of compact tension specimens that were used for SCC crack growth rate testing in simulated PWR primary water. Hardness and the EBSD integrated misorientation density could both be related to the degree of cold work for materials of similar grain size. However, a microstructural dependence was observed for strain correlations using EBSD and hardness which should be considered if this technique is to be used for gaining insight on SCC growth rates

  4. Ultra-high aspect ratio high-resolution nanofabrication for hard X-ray diffractive optics.

    PubMed

    Chang, Chieh; Sakdinawat, Anne

    2014-06-27

    Although diffractive optics have played a major role in nanoscale soft X-ray imaging, high-resolution and high-efficiency diffractive optics have largely been unavailable for hard X-rays where many scientific, technological and biomedical applications exist. This is owing to the long-standing challenge of fabricating ultra-high aspect ratio high-resolution dense nanostructures. Here we report significant progress in ultra-high aspect ratio nanofabrication of high-resolution, dense silicon nanostructures using vertical directionality controlled metal-assisted chemical etching. The resulting structures have very smooth sidewalls and can be used to pattern arbitrary features, not limited to linear or circular. We focus on the application of X-ray zone plate fabrication for high-efficiency, high-resolution diffractive optics, and demonstrate the process with linear, circular, and spiral zone plates. X-ray measurements demonstrate high efficiency in the critical outer layers. This method has broad applications including patterning for thermoelectric materials, battery anodes and sensors among others.

  5. Fabrication of X-ray Mirror for Hard X-ray Diffraction Limited Nanofocusing

    SciTech Connect

    Yumoto, Hirokatsu; Mimura, Hidekazu; Matsuyama, Satoshi; Handa, Soichiro; Shibatani, Akihiko; Katagishi, Keiko; Yamamura, Kazuya; Sano, Yasuhisa; Endo, Katsuyoshi; Mori, Yuzo; Yamauchi, Kazuto; Yabashi, Makina

    2007-01-19

    We designed, fabricated and evaluated a total-reflection mirror having a designed focal size of 28 nm at 15keV. Line-focus tests on the fabricated mirror were carried out at the 1-km-long beamline (BL29XUL) of SPring-8. Nearly diffraction-limited performance with a full width at half maximum spot size of 30 nm was realized at 15 keV. We are planning to fabricate multilayer-coated mirror for realizing sub-10-nm focusing in hard x-ray region. We suggest a novel method of at-wavelength metrology. Wave-front error on the mirror surface can be estimated by a phase retrieval method using the intensity profile around the focal point. By correcting the estimated wave-front errors, sub-10-nm focusing is potentially feasible.

  6. Hard diffraction at DESY HERA and the gluonic content of the Pomeron

    SciTech Connect

    Capella, A.; Kaidalov, A.; Merino, C.; Pertermann, D.; Tran Thanh Van, J.

    1996-03-01

    We show that the previously introduced CKMT model, based on conventional Regge theory, gives a good description of the data from DESY HERA on the structure function {ital F}{sup {ital D}}{sub 2} for large rapidity gap (diffractive) events. These data allow us not only to determine the valence and sea quark content of the Pomeron, but also, through their {ital Q}{sup 2} dependence, give us information on its gluonic content. Using DGLAP evolution, we find that the gluon distribution in the Pomeron is very hard and the gluons carry more momentum than the quarks. This indicates that the Pomeron, unlike ordinary hadrons, is a mostly gluonic object. With our definition of the Pomeron flux factor the total momentum carried by quarks and gluons turns out to be 0.3{endash}0.4, strongly violating the momentum sum rule. {copyright} {ital 1996 The American Physical Society.}

  7. Wave packet autocorrelation functions for quantum hard-disk and hard-sphere billiards in the high-energy, diffraction regime.

    PubMed

    Goussev, Arseni; Dorfman, J R

    2006-07-01

    We consider the time evolution of a wave packet representing a quantum particle moving in a geometrically open billiard that consists of a number of fixed hard-disk or hard-sphere scatterers. Using the technique of multiple collision expansions we provide a first-principle analytical calculation of the time-dependent autocorrelation function for the wave packet in the high-energy diffraction regime, in which the particle's de Broglie wavelength, while being small compared to the size of the scatterers, is large enough to prevent the formation of geometric shadow over distances of the order of the particle's free flight path. The hard-disk or hard-sphere scattering system must be sufficiently dilute in order for this high-energy diffraction regime to be achievable. Apart from the overall exponential decay, the autocorrelation function exhibits a generally complicated sequence of relatively strong peaks corresponding to partial revivals of the wave packet. Both the exponential decay (or escape) rate and the revival peak structure are predominantly determined by the underlying classical dynamics. A relation between the escape rate, and the Lyapunov exponents and Kolmogorov-Sinai entropy of the counterpart classical system, previously known for hard-disk billiards, is strengthened by generalization to three spatial dimensions. The results of the quantum mechanical calculation of the time-dependent autocorrelation function agree with predictions of the semiclassical periodic orbit theory.

  8. Coherent diffraction imaging analysis of shape-controlled nanoparticles with focused hard X-ray free-electron laser pulses.

    PubMed

    Takahashi, Yukio; Suzuki, Akihiro; Zettsu, Nobuyuki; Oroguchi, Tomotaka; Takayama, Yuki; Sekiguchi, Yuki; Kobayashi, Amane; Yamamoto, Masaki; Nakasako, Masayoshi

    2013-01-01

    We report the first demonstration of the coherent diffraction imaging analysis of nanoparticles using focused hard X-ray free-electron laser pulses, allowing us to analyze the size distribution of particles as well as the electron density projection of individual particles. We measured 1000 single-shot coherent X-ray diffraction patterns of shape-controlled Ag nanocubes and Au/Ag nanoboxes and estimated the edge length from the speckle size of the coherent diffraction patterns. We then reconstructed the two-dimensional electron density projection with sub-10 nm resolution from selected coherent diffraction patterns. This method enables the simultaneous analysis of the size distribution of synthesized nanoparticles and the structures of particles at nanoscale resolution to address correlations between individual structures of components and the statistical properties in heterogeneous systems such as nanoparticles and cells.

  9. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    SciTech Connect

    Xie, Miao; Mohammadi, Reza; Turner, Christopher L.; Kaner, Richard B.; Kavner, Abby; Tolbert, Sarah H.

    2015-07-29

    In this paper, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under nonhydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

  10. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    SciTech Connect

    Xie, Miao; Turner, Christopher L.; Mohammadi, Reza; Kaner, Richard B. E-mail: akavner@ucla.edu Tolbert, Sarah H. E-mail: akavner@ucla.edu; Kavner, Abby E-mail: akavner@ucla.edu

    2015-07-27

    In this work, we explore the hardening mechanisms in WB{sub 4}-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB{sub 4} solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

  11. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    DOE PAGES

    Xie, Miao; Mohammadi, Reza; Turner, Christopher L.; ...

    2015-07-29

    In this paper, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under nonhydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

  12. Characterizing the hard x-ray diffraction properties of a GaAs linear Bragg-Fresnel lens

    SciTech Connect

    Li, Youli; Wong, Gerard C. L.; Case, Ryan; Safinya, Cyrus R.; Caine, Ernie; Hu, Evelyn; Fernandez, Partricia

    2000-07-17

    We investigated the diffractive focusing properties of (111) GaAs linear Bragg-Fresnel lenses (BFLs) developed for hard x-ray microscopy and microdiffraction of complex materials in confined geometries. We demonstrated that the use of GaAs yields significant processing advantages due to the reduced zone depth. Focal plane diffraction patterns of linear BFLs measured at the advanced photon source using 8-40 keV x rays were compared to a simple model based on Kirchhoff-Fresnel diffraction theory. Good agreement was obtained between experimental data and model calculations using only zones within an effective aperture defined by the transverse coherence of the source. (c) 2000 American Institute of Physics.

  13. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source.

    PubMed

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N; Daurer, Benedikt J; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F; Higashiura, Akifumi; Hogue, Brenda G; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A; Reddy, Hemanth K N; Lan, Ti-Yen; Larsson, Daniel S D; Liu, Haiguang; Loh, N Duane; Maia, Filipe R N C; Mancuso, Adrian P; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M Marvin; Sellberg, Jonas A; Sierra, Raymond G; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A; Westphal, Daniel; Wiedorn, Max O; Williams, Garth J; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-08-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

  14. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    PubMed Central

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J.; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N.; Daurer, Benedikt J.; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F.; Higashiura, Akifumi; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Reddy, Hemanth K.N.; Lan, Ti-Yen; Larsson, Daniel S.D.; Liu, Haiguang; Loh, N. Duane; Maia, Filipe R.N.C.; Mancuso, Adrian P.; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M. Marvin; Sellberg, Jonas A.; Sierra, Raymond G.; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A.; Westphal, Daniel; Wiedorn, Max O.; Williams, Garth J.; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-01-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here. PMID:27478984

  15. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    SciTech Connect

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J.; Berntsen, Peter; Bielecki, Johan; Boutet, Sebastien; Bucher, Maximilian; Chapman, Henry N.; Daurer, Benedikt J.; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F.; Higashiura, Akifumi; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Reddy, Hemanth K. N.; Lan, Ti -Yen; Larsson, Daniel S. D.; Liu, Haiguang; Loh, N. Duane; Maia, Filipe R. N. C.; Mancuso, Adrian P.; Muhlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M. Marvin; Sellberg, Jonas A.; Sierra, Raymond G.; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A.; Westphal, Daniel; Wiedorn, Max O.; Williams, Garth J.; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-08-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. Here, the diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

  16. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    DOE PAGES

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; ...

    2016-08-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. Here, the diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB)more » as a resource for algorithm development, the contents of which are described here.« less

  17. Exclusive diffractive production of pion pairs and resonances in proton-proton collisions within tensor pomeron approach

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr

    2017-03-01

    The central exclusive production of π+π- pairs in proton-(anti)proton collisions is studied in the framework of tensor pomeron model. We discuss the purely diffractive processes (dipion continuum, scalar and tensor resonant contributions) and the photoproduction processes (ρ0 and Drell-Söding mechanism). The theoretical results are compared with the STAR, CDF and CMS experimental data. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles, e.g. the distributions in two-pion invariant mass and transverse momentum of the pion pair. We find that the relative contribution of resonant f2(1270) and dipion continuum strongly depends on the cut on proton transverse momenta (or four-momentum transfer squared). In the case of exclusive central 4π production we include the contribution via the intermediate σσ and ρρ states. For both processes the theoretical results have been compared with the ISR experimental data and predictions for planned or being carried out experiments (e.g. STAR, ATLAS-ALFA) are presented.

  18. High mass exclusive diffractive dijet production in $\\mathbf{p\\bar{p}}$ collisions at $\\mathbf{\\sqrt{s}}$ = 1.96 TeV

    SciTech Connect

    Abazov, V.

    2010-09-01

    We present evidence for diffractive exclusive dijet production with an invariant dijet mass greater than 100 GeV in data collected with the D0 experiment at the Fermilab Tevatron Collider. A discriminant based on calorimeter information is used to measure a significant number of events with little energy (typically less than 10 GeV) outside the dijet system, consistent with the diffractive exclusive dijet production topology. The probability for these events to be explained by other dijet production processes is 2 x 10{sup -5}, corresponding to a 4.1 standard deviation significance.

  19. Spectrometer for hard X-ray free-electron laser based on diffraction focusing.

    PubMed

    Kohn, V G; Gorobtsov, O Y; Vartanyants, I A

    2013-03-01

    X-ray free-electron lasers (XFELs) generate sequences of ultra-short spatially coherent pulses of X-ray radiation. A diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of ΔE/E 2 × 10(-6), is proposed. This is much better than for most modern X-ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single-crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from a metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. It is shown that the DFS can be used in a wide energy range from 5 keV to 20 keV.

  20. Mapping the Strain Distributions in Deformed Bulk Metallic Glasses Using Hard X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Bednarcik, J.; Chen, L. Y.; Wang, X. D.; Jiang, J. Z.; Franz, H.

    2012-05-01

    The deformation behavior of Cu45 Zr46.5 Al7Ti1.5 bulk metallic glass (BMG) under bending was investigated in-situ using high-energy X-ray synchrotron diffraction. Samples were bent using two different benders with radii of 10 and 20 mm. The components of the strain tensor were determined from the change of positions of the first maximum of the diffracted intensity in reciprocal space. The procedure of data treatment was improved by the introduction of direct beam off-center correction. Comparing results for the two different bending radii, we found that the zero stress region does not necessarily lay within the central part of the specimen. Bending with smaller radius resulted in symmetric strain distribution, whereas a larger bending radius revealed strong asymmetry. Furthermore, bending with a smaller radius (10 mm) shows steeper strain gradients as compared with the situation in which the larger bending radius (20 mm) was used. Using a smaller bending radius implies reaching higher tensile/compressive stresses and reveals the signs of the plastic deformation, which are demonstrated as a saturation of elastic strains.

  1. Damage investigation on tungsten and diamond diffractive optics at a hard x-ray free-electron laser.

    PubMed

    Uhlén, Fredrik; Nilsson, Daniel; Holmberg, Anders; Hertz, Hans M; Schroer, Christian G; Seiboth, Frank; Patommel, Jens; Meier, Vivienne; Hoppe, Robert; Schropp, Andreas; Lee, Hae Ja; Nagler, Bob; Galtier, Eric; Krzywinski, Jacek; Sinn, Harald; Vogt, Ulrich

    2013-04-08

    Focusing hard x-ray free-electron laser radiation with extremely high fluence sets stringent demands on the x-ray optics. Any material placed in an intense x-ray beam is at risk of being damaged. Therefore, it is crucial to find the damage thresholds for focusing optics. In this paper we report experimental results of exposing tungsten and diamond diffractive optics to a prefocused 8.2 keV free-electron laser beam in order to find damage threshold fluence levels. Tungsten nanostructures were damaged at fluence levels above 500 mJ/cm(2). The damage was of mechanical character, caused by thermal stress variations. Diamond nanostructures were affected at a fluence of 59 000 mJ/cm(2). For fluence levels above this, a significant graphitization process was initiated. Scanning Electron Microscopy (SEM) and µ-Raman analysis were used to analyze exposed nanostructures.

  2. Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources

    PubMed Central

    Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

    2017-01-01

    Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu Kα wavelength with a photon flux of up to 109 photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source. PMID:28795079

  3. Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources.

    PubMed

    Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

    2017-09-01

    Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu K α wavelength with a photon flux of up to 10(9) photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source.

  4. Next-to-Leading Order Computation of Exclusive Diffractive Light Vector Meson Production in a Saturation Framework

    NASA Astrophysics Data System (ADS)

    Boussarie, R.; Grabovsky, A. V.; Ivanov, D. Yu.; Szymanowski, L.; Wallon, S.

    2017-08-01

    We perform the first next-to-leading order computation of the γ(*)→V (ρ ,ϕ ,ω ) exclusive impact factor in the QCD shock-wave approach and in the most general kinematics. This paves the way to the very first quantitative study of high-energy nucleon and nucleus saturation beyond the leading order for a whole range of small-x exclusive processes, to be measured in e p , e A , p p , and p A collisions at existing and future colliders.

  5. The Molecular Architecture for the Intermediate Filaments of Hard α -Keratin Based on the Superlattice Data Obtained from a Study of Mammals Using Synchrotron Fibre Diffraction

    DOE PAGES

    James, Veronica

    2011-01-01

    High- and low-angle X-ray diffraction studies of hard α -keratin have been studied, and various models have been proposed over the last 70 years. Most of these studies have been confined to one or two forms of alpha keratin. This high- and low-angle synchrotron fibre diffraction study extends the study to cover all available data for all known forms of hard α -keratin including hairs, fingernails, hooves, horn, and quills from mammals, marsupials, and a monotreme, and it confirms that the model proposed is universally acceptable for all mammals. A complete Bragg analysis of the meridional diffraction patterns, includingmore » multiple-time exposures to verify any weak reflections, verified the existence of a superlattice consisting of two infinite lattices and three finite lattices. An analysis of the equatorial patterns establishes the radii of the oligomeric levels of dimers, tetramers, and intermediate filaments (IFs) together with the centre to centre distance for the IFs, thus confirming the proposed helices within helices molecular architecture for hard α -keratin. The results verify that the structure proposed by Feughelman and James meets the criteria for a valid α -keratin structure.« less

  6. The Molecular Architecture for the Intermediate Filaments of Hard α-Keratin Based on the Superlattice Data Obtained from a Study of Mammals Using Synchrotron Fibre Diffraction.

    PubMed

    James, Veronica

    2011-01-01

    High- and low-angle X-ray diffraction studies of hard α-keratin have been studied, and various models have been proposed over the last 70 years. Most of these studies have been confined to one or two forms of alpha keratin. This high- and low-angle synchrotron fibre diffraction study extends the study to cover all available data for all known forms of hard α-keratin including hairs, fingernails, hooves, horn, and quills from mammals, marsupials, and a monotreme, and it confirms that the model proposed is universally acceptable for all mammals. A complete Bragg analysis of the meridional diffraction patterns, including multiple-time exposures to verify any weak reflections, verified the existence of a superlattice consisting of two infinite lattices and three finite lattices. An analysis of the equatorial patterns establishes the radii of the oligomeric levels of dimers, tetramers, and intermediate filaments (IFs) together with the centre to centre distance for the IFs, thus confirming the proposed helices within helices molecular architecture for hard α-keratin. The results verify that the structure proposed by Feughelman and James meets the criteria for a valid α-keratin structure.

  7. The Molecular Architecture for the Intermediate Filaments of Hard α-Keratin Based on the Superlattice Data Obtained from a Study of Mammals Using Synchrotron Fibre Diffraction

    PubMed Central

    James, Veronica

    2011-01-01

    High- and low-angle X-ray diffraction studies of hard α-keratin have been studied, and various models have been proposed over the last 70 years. Most of these studies have been confined to one or two forms of alpha keratin. This high- and low-angle synchrotron fibre diffraction study extends the study to cover all available data for all known forms of hard α-keratin including hairs, fingernails, hooves, horn, and quills from mammals, marsupials, and a monotreme, and it confirms that the model proposed is universally acceptable for all mammals. A complete Bragg analysis of the meridional diffraction patterns, including multiple-time exposures to verify any weak reflections, verified the existence of a superlattice consisting of two infinite lattices and three finite lattices. An analysis of the equatorial patterns establishes the radii of the oligomeric levels of dimers, tetramers, and intermediate filaments (IFs) together with the centre to centre distance for the IFs, thus confirming the proposed helices within helices molecular architecture for hard α-keratin. The results verify that the structure proposed by Feughelman and James meets the criteria for a valid α-keratin structure. PMID:22028970

  8. The Molecular Architecture for the Intermediate Filaments of Hard [alpha]-Keratin Based on the Superlattice Data Obtained from a Study ofMammals Using Synchrotron Fibre Diffraction

    SciTech Connect

    James, Veronica

    2014-09-24

    High- and low-angle X-ray diffraction studies of hard {alpha}-keratin have been studied, and various models have been proposed over the last 70 years. Most of these studies have been confined to one or two forms of alpha keratin. This high- and low-angle synchrotron fibre diffraction study extends the study to cover all available data for all known forms of hard {alpha}-keratin including hairs, fingernails, hooves, horn, and quills from mammals, marsupials, and a monotreme, and it confirms that the model proposed is universally acceptable for all mammals. A complete Bragg analysis of the meridional diffraction patterns, including multiple-time exposures to verify any weak reflections, verified the existence of a superlattice consisting of two infinite lattices and three finite lattices. An analysis of the equatorial patterns establishes the radii of the oligomeric levels of dimers, tetramers, and intermediate filaments (IFs) together with the centre to centre distance for the IFs, thus confirming the proposed helices within helices molecular architecture for hard {alpha}-keratin. The results verify that the structure proposed by Feughelman and James meets the criteria for a valid {alpha}-keratin structure.

  9. Experimental results on diffraction at CDF

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U. /Lisbon, LIFEP

    2010-09-01

    Diffractive events are studied by means of identification of one or more rapidity gaps and/or a leading antiproton. Measurements of soft and hard diffractive processes have been performed at the Tevatron p{bar p} collider and presented. We report on the diffractive structure function obtained from dijet production in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, and on the |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}. Results on single diffractive W/Z production, forward jets, and central exclusive production of both dijets and Z-bosons are also presented.

  10. Probing the Small- x Gluon Tomography in Correlated Hard Diffractive Dijet Production in Deep Inelastic Scattering

    SciTech Connect

    Hatta, Yoshitaka; Xiao, Bo-Wen; Yuan, Feng

    2016-05-20

    The close connection between the quantum phase space Wigner distribution of small-x gluons and the color dipole scattering amplitude is investigated, and studying it experimentally is proposed in the hard diffractive dijet production at the planned electron-ion collider. The angular correlation between the nucleon recoiled momentum and the dijet transverse momentum probes the nontrivial correlation in the phase space Wigner distribution. This experimental study not only provides three-dimensional tomographic pictures of gluons inside high energy protons - it gives a unique and interesting signal for the small-x dynamics with QCD evolution effects.

  11. High-pass-filtered diffraction microtomography by coherent hard x rays for cell imaging: theoretical and numerical studies of the imaging and reconstruction principles.

    PubMed

    Yuasa, Tetsuya; Sugiyama, Hiroshi; Zhong, Zhong; Maksimenko, Anton; Dilmanian, F Avraham; Akatsuka, Takao; Ando, Masami

    2005-12-01

    This paper presents theoretical and numerical studies of diffraction tomography using hard x rays, from the viewpoint of imaging and reconstruction methods for cell imaging. The proposed system employs a single-perfect-crystal analyzer in symmetric Laue-case transmission geometry to efficiently detect the higher spatial frequency components of an object's refractive-index distribution, and to effectively suppress interference between the unperturbated wave field and the wave field diffracted by the object. This system features acquisition of a single projection by a single exposure using a simple geometry and aggressive use of diffracted x rays. We present the physical description of the imaging method using the Fourier diffraction theorem derived from the Born approximation. First, we demonstrate that the reconstruction leads to the phase-retrieval problem. We then describe a reconstruction algorithm based on the classical Gerchberg-Saxton-Fienup algorithm. Finally, we show the efficacy of this system by computer simulation. Our simulation demonstrates that the imaging system delineates microstructure 3.5 microm in diameter in a phase object 400 microm in diameter.

  12. Preliminary design of a zone plate based hard X-ray monochromatic diffraction nanoprobe for materials studies at APS

    NASA Astrophysics Data System (ADS)

    Cai, Zhonghou; Liu, Wenjun; Tischler, Jonathan Z.; Shu, Deming; Xu, Ruqing; Schmidt, Oliver

    2013-09-01

    Aiming at studies of the micro/nano-structures of a broad range materials and electronic devices, Advance Photon Source (APS) is developing a dedicated diffraction nanoprobe (DNP) beamline for the needs arising from a multidiscipline research community. As a part of the APS Upgrade Project, the planed facility, named Sub-micron 3-D Diffraction (S3DD) beamline1, integrates the K-B mirror based polychromatic Laue diffraction and the Fresnel zone-plate based monochromatic diffraction techniques that currently support 3D/2D microdiffraction programs at the 34-ID-E and 2-ID-D of the APS, respectively. Both diffraction nanoprobes are designed to have a 50-nm or better special resolution. The zone-plate based monochromatic DNP has been preliminarily designed and will be constructed at the sector 34-ID. It uses an APS-3.0-cm period or APS-3.3-cm period undulator, a liquid-nitrogen cooled mirror as its first optics, and a water cooled small gap silicon double-crystal monochromator with an energy range of 5-30 keV. A set of zone plates have been designed to optimize for focusing efficiency and the working distance based on the attainable beamline length and the beam coherence. To ensure the nanoprobe performance, high stiffness and high precision flexure stage systems have been designed or demonstrated for optics mounting and sample scanning, and high precision temperature control of the experimental station will be implemented to reduce thermal instability. Designed nanoprobe beamline has a good management on thermal power loading on optical components and allows high degree of the preservation of beam brilliance for high focal flux and coherence. Integrated with variety of X-ray techniques, planed facility provides nano-XRD capability with the maximum reciprocal space accessibility and allows micro/nano-spectroscopy studies with K-edge electron binding energies of most elements down to Vanadium in the periodic table. We will discuss the preliminary design of the zone

  13. Detection of charge scattering associated with stripe order in La1.775Sr0.225NiO4 by hard-x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Vigliante, A.; von Zimmermann, M.; Schneider, J. R.; Frello, T.; Andersen, N. H.; Madsen, J.; Buttrey, D. J.; Gibbs, Doon; Tranquada, J. M.

    1997-10-01

    In the past few years neutron-scattering experiments have shown very intriguing stripe correlations of spins and holes in hole-doped La2NiO4 and La2CuO4. As yet, no x-ray-diffraction experiment has confirmed the neutron results and the topic is still controversial. In this paper we report the observation of stripe correlations of holes by x-ray diffraction. The experiments were performed in Laue geometry at the hard-x-ray beamline BW5 at HASYLAB on a crystal of La1.775Sr0.225NiO4 which was previously studied by neutron diffraction. Temperature dependences of the intensities and wave vectors of the charge-density-modulation peaks were characterized and found to be in good agreement with the neutron-scattering results. Interestingly, weak, temperature-dependent scattering was also observed at positions consistent with nonresonant x-ray magnetic scattering from the spin correlations; however, a definitive determination of its origin remains lacking.

  14. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    PubMed

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu, Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of ΔE(X) ≃ 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E(H) = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  15. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    SciTech Connect

    Stoupin, S.; Shvydko, Y.; Shu, D.; Khachatryan, R.; Xiao, X.

    2012-01-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  16. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

    SciTech Connect

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-15

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  17. Reconstruction of an astigmatic hard X-ray beam and alignment of K-B mirrors from ptychographic coherent diffraction data.

    PubMed

    Kewish, Cameron M; Guizar-Sicairos, Manuel; Liu, Chian; Qian, Jun; Shi, Bing; Benson, Christa; Khounsary, Ali M; Vila-Comamala, Joan; Bunk, Oliver; Fienup, James R; Macrander, Albert T; Assoufid, Lahsen

    2010-10-25

    We have used coherent X-ray diffraction experiments to characterize both the 1-D and 2-D foci produced by nanofocusing Kirkpatrick-Baez (K-B) mirrors, and we find agreement. Algorithms related to ptychography were used to obtain a 3-D reconstruction of a focused hard X-ray beam waist, using data measured when the mirrors were not optimally aligned. Considerable astigmatism was evident in the reconstructed complex wavefield. Comparing the reconstructed wavefield for a single mirror with a geometrical projection of the wavefront errors expected from optical metrology data allowed us to diagnose a 40 μrad misalignment in the incident angle of the first mirror, which had occurred during the experiment. Good agreement between the reconstructed wavefront obtained from the X-ray data and off-line metrology data obtained with visible light demonstrates the usefulness of the technique as a metrology and alignment tool for nanofocusing X-ray optics.

  18. Central exclusive diffractive production of the π+π- continuum, scalar, and tensor resonances in p p and p p ¯ scattering within the tensor Pomeron approach

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

    2016-03-01

    We consider central exclusive diffractive dipion production in the reactions p p →p p π+π- and p p ¯ →p p ¯ π+π- at high energies. We include the dipion continuum, the dominant scalar f0(500 ), f0(980 ) , and tensor f2(1270 ) resonances decaying into the π+π- pairs. The calculation is based on a tensor Pomeron model and the amplitudes for the processes are formulated in terms of vertices respecting the standard crossing and charge-conjugation relations of quantum field theory. The formulas for the dipion continuum and tensor meson production are given here for the first time. The theoretical results are compared with existing STAR, CDF, CMS experimental data and predictions for planned or current experiments (ALICE, ATLAS) are presented. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles. Distributions in rapidities and transverse momenta of outgoing protons and pions as well as correlations in azimuthal angle between them are presented. We find that the relative contribution of the resonant f2(1270 ) and dipion continuum strongly depends on the cut on proton transverse momenta or four-momentum transfer squared t1 ,2 which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a π π resonance filter. We suggest some experimental analyses to fix model parameters related to the Pomeron-Pomeron-f2 coupling.

  19. HYBRID Simulations of Diffraction-Limited Focusing with Kirkpatrick-Baez Mirrors for a Next-Generation In Situ Hard X-ray Nanoprobe

    NASA Astrophysics Data System (ADS)

    Maser, Jörg; Shi, Xianbo; Reininger, Ruben; Lai, Barry; Vogt, Stefan

    2016-12-01

    Next-generation hard X-ray nanoprobe beamlines such as the In Situ Nanoprobe (ISN) beamline being planned at the Advanced Photon Source aim at providing very high spatial resolution while also enabling very high focused flux, to study complex materials and devices using fast, multidimensional imaging across many length scales. The ISN will use diffractive optics to focus X-rays with a bandpass of ∆ E/ E = 10-4 into a focal spot of 20 nm or below. Reflective optics in Kirkpatrick-Baez geometry will be used to focus X-rays with a bandpass as large as ∆ E/ E = 10-2 into a focal spot of 50 nm. Diffraction-limited focusing with reflective optics is achieved by spatial filtering and use of a very long, vertically focusing mirror. To quantify the performance of the ISN beamline, we have simulated the propagation of both partially and fully coherent wavefronts from the undulator source, through the ISN beamline and into the mirror-based focal spot. Simulations were carried out using the recently developed software " HYBRID."

  20. HYBRID simulations of diffraction-limited focusing with Kirkpatrick-Baez mirrors for a next-generation In Situ hard X-ray nanoprobe

    DOE PAGES

    Maser, Jorg; Shi, Xianbo; Reininger, Ruben; ...

    2016-02-22

    Next-generation hard X-ray nanoprobe beamlines such as the In Situ Nanoprobe (ISN) beamline being planned at the Advanced Photon Source aim at providing very high spatial resolution while also enabling very high focused flux, to study complex materials and devices using fast, multidimensional imaging across many length scales. The ISN will use diffractive optics to focus X-rays with a bandpass of ΔE/E = 10–4 into a focal spot of 20 nm or below. Reflective optics in Kirkpatrick-Baez geometry will be used to focus X-rays with a bandpass as large as ΔE/E = 10–2 into a focal spot of 50 nm.more » Diffraction-limited focusing with reflective optics is achieved by spatial filtering and use of a very long, vertically focusing mirror. Furthermore, to quantify the performance of the ISN beamline, we have simulated the propagation of both partially and fully coherent wavefronts from the undulator source, through the ISN beamline and into the mirror-based focal spot. Simulations were carried out using the recently developed software “HYBRID.”« less

  1. HYBRID simulations of diffraction-limited focusing with Kirkpatrick-Baez mirrors for a next-generation In Situ hard X-ray nanoprobe

    SciTech Connect

    Maser, Jorg; Shi, Xianbo; Reininger, Ruben; Lai, Barry; Vogt, Stefan

    2016-02-22

    Next-generation hard X-ray nanoprobe beamlines such as the In Situ Nanoprobe (ISN) beamline being planned at the Advanced Photon Source aim at providing very high spatial resolution while also enabling very high focused flux, to study complex materials and devices using fast, multidimensional imaging across many length scales. The ISN will use diffractive optics to focus X-rays with a bandpass of ΔE/E = 10–4 into a focal spot of 20 nm or below. Reflective optics in Kirkpatrick-Baez geometry will be used to focus X-rays with a bandpass as large as ΔE/E = 10–2 into a focal spot of 50 nm. Diffraction-limited focusing with reflective optics is achieved by spatial filtering and use of a very long, vertically focusing mirror. Furthermore, to quantify the performance of the ISN beamline, we have simulated the propagation of both partially and fully coherent wavefronts from the undulator source, through the ISN beamline and into the mirror-based focal spot. Simulations were carried out using the recently developed software “HYBRID.”

  2. Soft Classification of Diffractive Interactions at the LHC

    SciTech Connect

    Kuusela, Mikael; Malmi, Eric; Orava, Risto; Vatanen, Tommi

    2011-07-15

    Multivariate machine learning techniques provide an alternative to the rapidity gap method for event-by-event identification and classification of diffraction in hadron-hadron collisions. Traditionally, such methods assign each event exclusively to a single class producing classification errors in overlap regions of data space. As an alternative to this so called hard classification approach, we propose estimating posterior probabilities of each diffractive class and using these estimates to weigh event contributions to physical observables. It is shown with a Monte Carlo study that such a soft classification scheme is able to reproduce observables such as multiplicity distributions and relative event rates with a much higher accuracy than hard classification.

  3. Diffraction Results from CDF

    SciTech Connect

    Goulianos, Konstantin

    2012-04-01

    We present final results by the CDF II collaboration on diffractive W and Z production, report on the status of ongoing analyses on diffractive dijet production and on rapidity gaps between jets, and briefly summarize results obtained on exclusive production pointing to their relevance to calibrating theoretical models used to predict exclusive Higgs-boson production at the LHC.

  4. Hard-x-ray region tomographic reconstruction of the refractive-index gradient vector field: imaging principles and comparisons with diffraction-enhanced-imaging-based computed tomography.

    PubMed

    Yuasa, Tetsuya; Maksimenko, Anton; Hashimoto, Eiko; Sugiyama, Hiroshi; Hyodo, Kazuyuki; Akatsuka, Takao; Ando, Masami

    2006-06-15

    The unique tomographic imaging method based on refractive effects that was recently developed by Maksimenko et al. [Appl. Phys. Lett. 86, 124105 (2005)] exhibits an excellent imaging property in the hard-x-ray region for phase objects such as soft materials and biological samples. However, there seems to have been little consideration of the physical aspects of the underlying imaging principles. Also, as the method is similar to diffraction-enhanced-imaging (DEI)-based computed tomography (CT), the difference between these two methodologies has not been made clear. We theoretically consider the imaging principles starting from the measurement process to the reconstruction procedures from the viewpoint of geometrical optics and then clarify their difference in relationship to the physical quantities to be depicted. The major feature of this novel method is the in-plane two-dimensional vector-field reconstruction of the refractive-index gradient in an object, while DEI CT obtains the out-of-plane scalar-field gradient component. In other words, the novel method and DEI CT present the transverse and the longitudinal components, respectively, of the three-dimensional vector fields of the gradient refractive index. Therefore they can be considered complementary to each other.

  5. Precise Magnetic Structures of Hard Ferromagnets of ND2FE14B Type as Determined at Low Temperature from Single Crystal Neutron Diffraction

    NASA Astrophysics Data System (ADS)

    Wolfers, P.; Bacmann, M.; Fruchart, D.

    2000-09-01

    The main constituent of the hard magnet materials Nd-Fe-B is the prototype of a new ferromagnet series, the Nd2Fe14B type (Space Group P42/nmm). Such compounds are characterised by high magnetocrystalline anisotropy parameters, those of rare earth origin being several times higher than the contribution of the iron subblattices. In many cases, these two contributions exhibit markedly different thermal behaviours, resulting in spin rotation phenomena or (and) lowering of the crystalline and the magnetic symmetry from the tetragonal high temperature state. Low temperature very precise studies on selected compounds of the series R2Fe14B with R = Nd, Ho, Er and Y, were undertaken by using neutron four circle diffractometry on single crystals. When temperature is lowered, the two first compounds exhibit a continuous spin reorientation within the [110] plane from the c-axis at high temperature towards an intermediate direction. The Er compound presents a first order transition around 350K where the resulting magnetisation first order rotates from the c-axis a high temperature to the a basal plane direction at low temperature. The last one compound remains c-easy axis in the whole temperature range. From our neutron diffraction experiments, lowering of the crystal symmetry to monoclinic (orthorhombic) space groups was precisely measured for the two first (third) samples. Besides marked deviations to collinearity affect the different sublattice magnetisations. Yet, these well marked phenomena have not been accounted for in the hundert experimental and theoretical analysis dedicated to the series. However, our results are in good agreement with a detailed 57Fe Mössbauer spectroscopy analysis of the Ho ternary hydrides.

  6. Exclusive diffractive production of π+π-π+π- via the intermediate σ σ and ρ ρ states in proton-proton collisions within tensor Pomeron approach

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

    2016-08-01

    We present first predictions of the cross sections and differential distributions for the central exclusive reaction p p →p p π+π-π+π- being studied at RHIC and LHC. The amplitudes for the processes are formulated in terms of the tensor Pomeron and tensor f2 R Reggeon exchanges with the vertices respecting the standard crossing and charge-conjugation relations of quantum field theory. The σ σ and ρ ρ contributions to the π+π-π+π- final state are considered, focusing on their specificities. The correct inclusion of the Pomeron spin structure seems crucial for the considered sequential mechanisms, in particular for the ρ ρ contribution which is treated here for the first time. The mechanism considered gives a significant contribution to the p p →p p π+π-π+π- reaction. We adjust parameters of our model to the CERN-ISR experimental data and present several predictions for the STAR, ALICE, ATLAS, and CMS experiments. A measurable cross section of order of a few μ b is obtained, including the experimental cuts relevant for the LHC experiments. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions.

  7. Hard X-ray diffraction study of charge stripe order in La1.48Nd0.4Sr0.12CuO4

    NASA Astrophysics Data System (ADS)

    Zimmermann, M. v.; Vigliante, A.; Niemöller, T.; Ichikawa, N.; Frello, T.; Madsen, J.; Wochner, P.; Uchida, S.; Andersen, N. H.; Tranquada, J. M.; Gibbs, D.; Schneider, J. R.

    1998-03-01

    High-energy photon diffraction is used to investigate the charge ordering previously studied by neutron diffraction in La1.48Nd0.4Sr0.12CuO4. Besides confirming the existence of superlattice peaks due to charge order, the temperature dependence of the peak intensity, width, and position has been determined with improved precision. Furthermore, we show that the scattered intensity has a sinusoidial modulation along c*, consistent with long-range Coulomb interactions between ordered charges within the CuO2 planes.

  8. Exclusive meson production at HERMES

    NASA Astrophysics Data System (ADS)

    Vandenbroucke, A.

    2005-10-01

    Generalized Parton Distributions (GPDs) provide a new level of insight into the quark structure of the nucleon. Experimentally they can be probed by hard exclusive electroproduction of both scalar and vector mesons. Results for the cross section for the reaction ep → enπ+, and a first result for the asymmetry AUT for exclusive ρ0 production are presented.

  9. Exclusive Dijet production from CDF2LHC

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2005-04-01

    Exclusive dijet production at the Tevatron can be used as a benchmark to establish predictions on exclusive diffractive Higgs production, a process with a much smaller cross section. Exclusive dijet production in Double Pomeron Exchange processes, including diffractive Higgs production with measurements at the Tevatron and predictions for the Large Hadron Collider are presented. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Upper limits on the exclusive dijet production cross section are presented and compared to current theoretical predictions.

  10. Evidence for high mass exclusive dijet production in the D0 experiment

    SciTech Connect

    Hubacek, Zdenek; /Prague, Tech. U.

    2010-10-01

    Exclusive diffractive Higgs boson production is an interesting process which could be studied at the Large Hadron Collider. While the cross section for the Higgs boson production at the Fermilab Tevatron Collider is too low for this channel, it is important to check if the class of exclusive diffraction events exists. We present the evidence for the high mass exclusive dijet production in the D0 experiment. Hard diffractive processes are usually described by the exchange of a colorless object called Pomeron. In diffractive hadron hadron collisions, the hadrons will exchange the Pomeron and either one or both hadrons will not dissolve. The events are identified by either a presence of a large forward region of the detector devoid of any activity (rapidity gap) or by a tagging of the intact beam hadron(s). A subset of diffractive events is called exclusive when the whole Pomeron energy is used to produce the diffractive state, i.e there are no Pomeron remnants. Exclusive diffractive production (EDP) of the Higgs boson or any other new final state X pp {yields} p + X + p has been recently proposed as a search channel at the LHC. The cross section for the Higgs boson production is too low at the Tevatron (0.2fb is predicted for a Higgs boson mass of 120 GeV), but it is important to check if this class of events exists in this kinematic region. The CDF Collaboration has recently confirmed the existence of EDP in several channels. In this report, we present the evidence for the exclusive production of high dijet invariant mass events, i.e. a dijet event accompanied by large rapidity gaps on both sides of the calorimeter.

  11. Diffractive physics results at CDF

    SciTech Connect

    Michele Gallinaro

    2003-12-18

    Forward detectors are described together with the first physics results from Run II. Using new data and dedicated diffractive triggers, a measurement of single diffractive dijet production rate, with particular focus on the diffractive structure function of the antiproton, is discussed. Upper limits on the exclusive dijet and {chi}{sub c}{sup 0} production cross sections are also presented.

  12. Implications of stimulated resonant X-ray scattering for spectroscopy, imaging, and diffraction in the regime from soft to hard X-rays

    NASA Astrophysics Data System (ADS)

    Schreck, Simon; Beye, Martin; Föhlisch, Alexander

    2015-12-01

    The ultrahigh peak brilliance available at X-ray free-electron lasers opens the possibility to transfer nonlinear spectroscopic techniques from the optical and infrared into the X-ray regime. Here, we present a conceptual treatment of nonlinear X-ray processes with an emphasis on stimulated resonant X-ray scattering as well as a quantitative estimate for the scaling of stimulated X-ray scattering cross sections. These considerations provide the order of magnitude for the required X-ray intensities to experimentally observe stimulated resonant X-ray scattering for photon energies ranging from the extreme ultraviolet to the soft and hard X-ray regimes. At the same time, the regime where stimulated processes can safely be ignored is identified. With this basis, we discuss prospects and implications for spectroscopy, scattering, and imaging experiments at X-ray free-electron lasers.

  13. Neutron and hard X-ray diffraction studies of the isothermal transformation kinetics in the research reactor fuel candidate U–8 wt%Mo

    PubMed Central

    Säubert, Steffen; Jungwirth, Rainer; Zweifel, Tobias; Hofmann, Michael; Hoelzel, Markus; Petry, Winfried

    2016-01-01

    Exposing uranium–molybdenum alloys (UMo) retained in the γ phase to elevated temperatures leads to transformation reactions during which the γ-UMo phase decomposes into the thermal equilibrium phases, i.e. U2Mo and α-U. Since α-U is not suitable for a nuclear fuel exposed to high burn-up, it is necessary to retain the γ-UMo phase during the production process of the fuel elements for modern high-performance research reactors. The present work deals with the isothermal transformation kinetics in U–8 wt%Mo alloys for temperatures between 673 and 798 K and annealing durations of up to 48 h. Annealed samples were examined at room temperature using either X-ray or neutron diffraction to determine the phase composition after thermal treatment, and in situ annealing studies disclosed the onset of phase decomposition. While for temperatures of 698 and 673 K the start of decomposition is delayed, for higher temperatures the first signs of transformation are already observable within 3 h of annealing. The typical C-shaped curves in a time–temperature–transformation (TTT) diagram for both the start and the end of phase decomposition could be determined in the observed temperature regime. Therefore, a revised TTT diagram for U–8 wt%Mo between 673 and 798 K and annealing durations of up to 48 h is proposed. PMID:27275139

  14. Neutron and hard X-ray diffraction studies of the isothermal transformation kinetics in the research reactor fuel candidate U-8 wt%Mo.

    PubMed

    Säubert, Steffen; Jungwirth, Rainer; Zweifel, Tobias; Hofmann, Michael; Hoelzel, Markus; Petry, Winfried

    2016-06-01

    Exposing uranium-molybdenum alloys (UMo) retained in the γ phase to elevated temperatures leads to transformation reactions during which the γ-UMo phase decomposes into the thermal equilibrium phases, i.e. U2Mo and α-U. Since α-U is not suitable for a nuclear fuel exposed to high burn-up, it is necessary to retain the γ-UMo phase during the production process of the fuel elements for modern high-performance research reactors. The present work deals with the isothermal transformation kinetics in U-8 wt%Mo alloys for temperatures between 673 and 798 K and annealing durations of up to 48 h. Annealed samples were examined at room temperature using either X-ray or neutron diffraction to determine the phase composition after thermal treatment, and in situ annealing studies disclosed the onset of phase decomposition. While for temperatures of 698 and 673 K the start of decomposition is delayed, for higher temperatures the first signs of transformation are already observable within 3 h of annealing. The typical C-shaped curves in a time-temperature-transformation (TTT) diagram for both the start and the end of phase decomposition could be determined in the observed temperature regime. Therefore, a revised TTT diagram for U-8 wt%Mo between 673 and 798 K and annealing durations of up to 48 h is proposed.

  15. Diffraction at Hera

    NASA Astrophysics Data System (ADS)

    Collard, C.

    2003-02-01

    At the electron-proton collider HERA, diffractive interactions represent ~ 10% of the deep inelastic scattering. The production of diffractive events, characterised by the presence of a gap in rapidity or angular region without particle production, can be explained in the framework of the Regge model by the exchange of a colorless object, named the Pomeron. Describing the nature of the pomeron is a challenge for Quantum Chromodynamics. Results from the H1 and ZEUS Collaborations on exclusive vector meson production and on inclusive diffractive processes are presented.

  16. Diffractive Measurements at the LHC: Elastic and Inelastic Soft Diffraction

    SciTech Connect

    Orava, Risto

    2011-07-15

    A short review of four topics was presented: (1) Photon bremsstrahlung in elastic proton-proton scattering, (2) Low mass Single Diffraction (SD), (3) Low mass Central Exclusive Diffraction (CED), and (4) Event classification of the pp interactions at the LHC. This article summarizes topic (1).

  17. New diffractive results from the Tevatron

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2005-05-01

    Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used to provide additional hints on exclusive dijet production.

  18. Hardness testing

    SciTech Connect

    Not Available

    1987-01-01

    This technical manual is a handbook dealing with all aspects of hardness testing. Every hardness testing method is fully covered, from Rockwell to ultrasonic hardness testing. Specific hardness testing problems are also discussed, and methods are offered for many applications. One chapter examines how to select the correct hardness testing method. A directory of manufacturers, distributors and suppliers of hardness testing equipment and supplies in the United States and Canada is also included. The book consist of eight chapters and an appendix. It discusses common concepts of hardness, and the theories and methods of hardness testing. Coverage includes specific hardness testing methods - Brinell, Rockwell, Vickers, and microhardness testing; and other hardness testing methods, such as scleroscope, ultrasonic, scratch and file testing, and hardness evaluation by eddy current testing.

  19. Central diffraction at ALICE

    NASA Astrophysics Data System (ADS)

    Lämsä, J. W.; Orava, R.

    2011-02-01

    The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, hybrids and new charmonium-like states. It would also provide a good testing ground for detailed studies of heavy quarkonia. Due to its central barrel performance, ALICE can accurately measure the low-mass central systems with good purity. The efficiency of the Forward Multiplicity Detector (FMD) and the Forward Shower Counter (FSC) system for detecting rapidity gaps is shown to be adequate for the proposed studies. With this detector arrangement, valuable new data can be obtained by tagging central diffractive processes.

  20. Multilayer diffraction at 104 keV

    NASA Technical Reports Server (NTRS)

    Krieger, Allen S.; Blake, Richard L.; Siddons, D. P.

    1993-01-01

    We have measured the diffraction peak of a W:Si synthetic multilayer reflector at 104 keV using the High Energy Bonse-Hart Camera at the X-17B hard X-ray wiggler beam line of the National Synchrotron Light Source at Brookhaven National Laboratory. The characteristics of the diffraction peak are described and compared to theory.

  1. Twenty years of diffraction at the Tevatron

    SciTech Connect

    Goulianos, K.; /Rockefeller U.

    2005-10-01

    Results on diffractive particle interactions from the Fermilab Tevatron {bar p}p collider are placed in perspective through a QCD inspired phenomenological approach, which exploits scaling and factorization properties observed in data. The results discussed are those obtained by the CDF Collaboration from a comprehensive set of single, double, and multigap soft and hard diffraction processes studied during the twenty year period since 1985, when the CDF diffractive program was proposed and the first Blois Workshop was held.

  2. Photon diffraction

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2009-11-01

    In current light models, a particle-like model of light is inconsistent with diffraction observations. A model of light is proposed wherein photon inferences are combined with the cosmological scalar potential model (SPM). That the photon is a surface with zero surface area in the travel direction is inferred from the Michelson-Morley experiment. That the photons in slits are mathematically treated as a linear antenna array (LAA) is inferred from the comparison of the transmission grating interference pattern and the single slit diffraction pattern. That photons induce a LAA wave into the plenum is inferred from the fractal model. Similarly, the component of the photon (the hod) is treated as a single antenna radiating a potential wave into the plenum. That photons are guided by action on the surface of the hod is inferred from the SPM. The plenum potential waves are a real field (not complex) that forms valleys, consistent with the pilot waves of the Bohm interpretation of quantum mechanics. Therefore, the Afshar experiment result is explained, supports Bohm, and falsifies Copenhagen. The papers may be viewed at http://web.citcom.net/˜scjh/.

  3. Photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    Fadley, Charles S.

    1987-01-01

    The use of core-level photoelectron diffraction for structural studies of surfaces and epitaxial overlayers is discussed. Photoelectron diffraction is found to provide several direct and rather unique types of structural information, including the sites and positions of adsorbed atoms; the orientations of small molecules or fragments bound to surfaces; the orientations, layer thicknesses, vertical lattice constants, and degrees of short-range order of epitaxial or partially-epitaxial overlayers; and the presence of short-range spin order in magnetic materials. Specific systems considered are the reaction of oxygen with Ni(001), the growth of epitaxial Cu on Ni(001), the well-defined test case S on Ni(001), and short-range spin order in the antiferromagnet KMnF3. A rather straightforward single scattering cluster (SSC) model also proves capable of quantitatively describing such data, particularly for near-surface species and with corrections for spherical-wave scattering effects and correlated vibrational motion. Promising new directions in such studies also include measurements with high angular resolution and the expanded use of synchrotron radiation.

  4. 37 CFR 404.7 - Exclusive, co-exclusive and partially exclusive licenses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Exclusive, co-exclusive and... Exclusive, co-exclusive and partially exclusive licenses. (a)(1) Exclusive, co-exclusive or partially... practical application or otherwise promote the invention's utilization by the public. (B) Exclusive,...

  5. 37 CFR 404.7 - Exclusive, co-exclusive and partially exclusive licenses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Exclusive, co-exclusive and..., co-exclusive and partially exclusive licenses. (a)(1) Exclusive, co-exclusive or partially exclusive... practical application or otherwise promote the invention's utilization by the public. (B) Exclusive,...

  6. 37 CFR 404.7 - Exclusive, co-exclusive and partially exclusive licenses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Exclusive, co-exclusive and... Exclusive, co-exclusive and partially exclusive licenses. (a)(1) Exclusive, co-exclusive or partially... practical application or otherwise promote the invention's utilization by the public. (B) Exclusive,...

  7. 37 CFR 404.7 - Exclusive, co-exclusive and partially exclusive licenses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Exclusive, co-exclusive and... Exclusive, co-exclusive and partially exclusive licenses. (a)(1) Exclusive, co-exclusive or partially... practical application or otherwise promote the invention's utilization by the public. (B) Exclusive,...

  8. 37 CFR 404.7 - Exclusive, co-exclusive and partially exclusive licenses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Exclusive, co-exclusive and..., co-exclusive and partially exclusive licenses. (a)(1) Exclusive, co-exclusive or partially exclusive... practical application or otherwise promote the invention's utilization by the public. (B) Exclusive,...

  9. Exclusive Reactions at High Momentum Transfer

    NASA Astrophysics Data System (ADS)

    Radyushkin, Anatoly; Stoler, Paul

    2008-03-01

    Hard exclusive scattering at JLab / P. Kroll -- AdS/CFT and exclusive processes in QCD / S. J. Brodsky and G. F. de Téramond -- Hadron structure matters in collisions at high energy and momentum / A. W. Thomas -- Inclusive perspectives / P. Hoyer -- Fitting DVCS at NLO and beyond / K. Kumericki, D. Müller and K. Passek-Kumericki -- Spin-orbit correlations and single-spin asymmetries / M. Burkardt -- Electroproduction of soft pions at large momentum transfers / V. M. Braun, D. Yu. Ivanov and A. Peters -- Color transparency: 33 years and still running / M. Strikman -- Meson clouds and nucleon electromagnetic form factors / G. A. Miller -- Covariance, dynamics and symmetries, and hadron form factors / M. S. Bhagwat, I. C. Cloët and C. D. Roberts -- N to [symbol] electromagnetic and axial form factors in full QCD / C. Alexandrou -- Real and virtual compton scattering in perturbative QCD / C.-R. Ji and R. Thomson -- Deeply virtual compton scattering at Jefferson Lab / F. Sabatie -- DVCS at HERMES: recent results / F. Ellinghaus -- Deeply virtual compton scattering with CLAS / F. X. Girod -- Deeply virtual compton scattering off the neutron at JLab Hall A / M. Mazouz -- The future DVCS experiments in Hall A at JLab / J. Roche -- Deeply virtual compton scattering with CLAS12 / L. Elouadrhiri -- Quark helicity flip and the transverse spin dependence of inclusive DIS / A. Afanasev, M. Strikman and C. Weiss -- Deeply virtual pseudoscalar meson production / V. Kubarovsky and P. Stoler -- Exclusive p[symbol] electroproduction on the proton: GPDs or not GPDs? / M. Guidal and S. Morrow -- p[symbol] transverse target spin asymmetry at HERMES / A. Airapetian -- Electroproduction of ø(1020) mesons / J. P. Santoro and E. S. Smith -- Generalized parton distributions from hadronic observables / S. Ahmad ... [et al.] -- Imaging the proton via hard exclusive production in diffractive pp scattering / G. E. Hyde ... [et al.] -- Regge contributions to exclusive electro-production / A

  10. Tests of quantum chromodynamics in exclusive and inclusive electroproduction

    SciTech Connect

    Brodsky, S.J.

    1989-06-01

    This paper discusses the following topics: overview of electroproduction phenomenology; hadronization of the quark and spectator systems; hadronization in nuclei; shadowing and anti- shadowing; color transparency; exclusive channels in electroproduction; hadronic wavefunction phenomenology; diffractive electroproduction; exclusive nuclear processes in QCD; and relation of electroproduction to QCD wavefunctions. 58 refs., 22 figs. (LSP)

  11. DISE: directed sphere exclusion.

    PubMed

    Gobbi, Alberto; Lee, Man-Ling

    2003-01-01

    The Sphere Exclusion algorithm is a well-known algorithm used to select diverse subsets from chemical-compound libraries or collections. It can be applied with any given distance measure between two structures. It is popular because of the intuitive geometrical interpretation of the method and its good performance on large data sets. This paper describes Directed Sphere Exclusion (DISE), a modification of the Sphere Exclusion algorithm, which retains all positive properties of the Sphere Exclusion algorithm but generates a more even distribution of the selected compounds in the chemical space. In addition, the computational requirement is significantly reduced, thus it can be applied to very large data sets.

  12. Fingerprinting ordered diffractions in multiply diffracted waves

    NASA Astrophysics Data System (ADS)

    Meles, Giovanni Angelo; Curtis, Andrew

    2014-09-01

    We show how to `fingerprint' individual diffractors inside an acoustic medium using interrogative wave energy from arrays of sources and receivers. For any recorded multiply diffracted wave observed between any source and any receiver, the set of such fingerprints is sufficient information to identify all diffractors involved in the corresponding diffraction path, and the sequential order in which diffractors are encountered. The method herein thus decomposes complex, multiply diffracted wavefields into constituent, single-diffraction interactions.

  13. Hard exclusive neutral pion production at Jefferson Lab Hall A

    SciTech Connect

    E. Fuchey

    2011-10-01

    We present measurements of the ep {yields} ep{pi}{sup 0} cross section extracted at two values of four-momentum transfer Q{sup 2} = 1.9 GeV{sup 2} and Q{sup 2} = 2.3 GeV{sup 2} at Jefferson Lab Hall A. The kinematic range allows to study the evolution of the cross section as a function of Q{sup 2} and W. Results will be confronted with Regge inspired calculations and GPD predictions. An interpretation of our data within the framework of semi-inclusive deep inelastic scattering has also been attempted.

  14. Hard exclusive neutral pion production at Jefferson Lab Hall A

    SciTech Connect

    Fuchey, E.

    2011-10-24

    We present measurements of the ep{yields}ep{pi}{sup 0} cross section extracted at two values of four-momentum transfer Q{sup 2} = 1.9 GeV{sup 2} and Q{sup 2} = 2.3 GeV{sup 2} at Jefferson Lab Hall A. The kinematic range allows to study the evolution of the cross section as a function of Q{sup 2} and W. Results will be confronted with Regge inspired calculations and GPD predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering has also been attempted.

  15. Results on diffraction from the D0 collaboration

    SciTech Connect

    Royon, Christophe

    2011-07-15

    We discuss the most recent results on diffraction from the D0 collaboration, the search for exclusive events in the jet channel at high dijet mass and the measurement of the elastic cross section using the Forward Proton Detector.

  16. Model of reversible vesicular transport with exclusion

    NASA Astrophysics Data System (ADS)

    Bressloff, Paul C.; Karamched, Bhargav R.

    2016-08-01

    A major question in neurobiology concerns the mechanics behind the motor-driven transport and delivery of vesicles to synaptic targets along the axon of a neuron. Experimental evidence suggests that the distribution of vesicles along the axon is relatively uniform and that vesicular delivery to synapses is reversible. A recent modeling study has made explicit the crucial role that reversibility in vesicular delivery to synapses plays in achieving uniformity in vesicle distribution, so called synaptic democracy (Bressloff et al 2015 Phys. Rev. Lett. 114 168101). In this paper we generalize the previous model by accounting for exclusion effects (hard-core repulsion) that may occur between molecular motor-cargo complexes (particles) moving along the same microtubule track. The resulting model takes the form of an exclusion process with four internal states, which distinguish between motile and stationary particles, and whether or not a particle is carrying vesicles. By applying a mean field approximation and an adiabatic approximation we reduce the system of ODEs describing the evolution of occupation numbers of the sites on a 1D lattice to a system of hydrodynamic equations in the continuum limit. We find that reversibility in vesicular delivery allows for synaptic democracy even in the presence of exclusion effects, although exclusion does exacerbate nonuniform distributions of vesicles in an axon when compared with a model without exclusion. We also uncover the relationship between our model and other models of exclusion processes with internal states.

  17. Central Exclusive Dijet Production

    SciTech Connect

    Dechambre, A.; Cudell, J. R.; Ivanov, I. P.; Hernandez, O.

    2008-08-29

    The ingredients of central exclusive production cross section include large perturbative corrections and soft quantities that must be parametrized and fitted to data. In this talk, we summarize the results of a study of the uncertainties coming from these ingredients, in the case of exclusive dijet production.

  18. Diffraction at the Tevatron: CDF results

    SciTech Connect

    Goulianos, Konstantin; /Rockefeller U.

    2006-11-01

    The diffractive program of the CDF Collaboration at the Fermilab Tevatron p{bar p} Collider is reviewed with emphasis on recent results from Run II at {radical}s = 1.96 TeV. Updated results on the x{sub B{sub j}} and Q{sup 2} dependence of the diffractive structure function obtained from dijet production, and on the slope parameter of the t-distribution of diffractive events as a function of Q{sup 2} in the range 1 GeV{sup 2} < Q{sup 2} < 10{sup 4} GeV{sup 2}, are presented and compared with theoretical expectations. Results on cross sections for exclusive dijet and diphoton production are also presented and used to calibrate theoretical estimates for exclusive Higgs production at the Large Hadron Collider.

  19. Mutually Exclusive Uncertainty Relations

    PubMed Central

    Xiao, Yunlong; Jing, Naihuan

    2016-01-01

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds. PMID:27824161

  20. Mutually Exclusive Uncertainty Relations.

    PubMed

    Xiao, Yunlong; Jing, Naihuan

    2016-11-08

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds.

  1. Mutually Exclusive Uncertainty Relations

    NASA Astrophysics Data System (ADS)

    Xiao, Yunlong; Jing, Naihuan

    2016-11-01

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds.

  2. Exclusive Processes in Quantum Chromodynamics and the Light-Cone Fock Representation

    SciTech Connect

    Brodsky, Stanley J.

    2000-12-07

    Exclusive processes provide a window into the bound state structure of hadrons in QCD as well as the fundamental processes which control hadron dynamics at the amplitude level. The natural calculus for describing bound state structure of relativistic composite systems needed for describing exclusive amplitudes is the light-cone Fock expansion which encodes the multi-quark, gluonic, and color correlations of a hadron in terms of frame-independent wavefunctions. In hard exclusive processes in which hadrons receive a large momentum transfer, perturbative QCD leads to factorization theorems which separate the physics of bound state structure from that of the relevant quark and gluonic hard-scattering reactions which underlie these reactions. At leading twist, the bound state physics is encoded in terms of universal ''distribution amplitudes,'' the fundamental theoretical quantities which describe the valence quark substructure of hadrons as well as nuclei. The combination of discretized light-cone quantization and transverse lattice methods are now providing nonperturbative predictions for the pion distribution amplitude. A basic feature of the gauge theory formalism is ''color transparency,'' the absence of initial and final state interactions of rapidly-moving compact color-singlet states. Other applications of the factorization formalism are briefly discussed, including semileptonic B decays, deeply virtual Compton scattering, and dynamical higher twist effects in inclusive reactions. A new type of jet production reaction, ''self-resolving diffractive interactions'' provide empirical constraints on the light-cone wavefunctions of hadrons in terms of their quark and gluon degrees of freedom as well as the composition of nuclei in terms of their nucleon and mesonic degrees of freedom.

  3. Higher order diffractions from a circular disk

    NASA Technical Reports Server (NTRS)

    Marsland, Diane P.; Balanis, Constantine A.; Brumley, Stephen A.

    1987-01-01

    The backscattering from a circular disk is analyzed using the geometrical theory of diffraction. First-, second-, and third-order diffractions are included in the hard polarization analysis, while first-, second-, and third-order slope diffractions are included for soft polarization. Improvements in the prediction of the monostatic radar cross section over previous works are noted. For hard polarization, an excellent agreement is exhibited between experimental and theoretical results, while a very good agreement is noted for soft polarization. To further improve the soft polarization results for wide angles, a model for the creeping wave or circulating current on the edge of the disk is obtained and used to find an additional component of the backscattered field. The addition of this component significantly improves the results for wide angles, leading to excellent agreement for soft polarization also. An axial-caustic correction method using equivalent currents is also included in the analysis.

  4. Higher order diffractions from a circular disk

    NASA Technical Reports Server (NTRS)

    Marsland, Diane P.; Balanis, Constantine A.; Brumley, Stephen A.

    1987-01-01

    The backscattering from a circular disk is analyzed using the geometrical theory of diffraction. First-, second-, and third-order diffractions are included in the hard polarization analysis, while first-, second-, and third-order slope diffractions are included for soft polarization. Improvements in the prediction of the monostatic radar cross section over previous works are noted. For hard polarization, an excellent agreement is exhibited between experimental and theoretical results, while a very good agreement is noted for soft polarization. To further improve the soft polarization results for wide angles, a model for the creeping wave or circulating current on the edge of the disk is obtained and used to find an additional component of the backscattered field. The addition of this component significantly improves the results for wide angles, leading to excellent agreement for soft polarization also. An axial-caustic correction method using equivalent currents is also included in the analysis.

  5. Exclusive processes and the fundamental structure of hadrons

    SciTech Connect

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD coupling in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.

  6. Exclusive processes and the fundamental structure of hadrons

    DOE PAGES

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD couplingmore » in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.« less

  7. ''Follow that quarkexclamation'' (and other exclusive stories)

    SciTech Connect

    Carroll, A.S.

    1987-06-17

    Quarks are considered to be the basic constituents of matter. In a series of recent experiments, Carroll studied exclusive reactions as a means of determining the interactions between quarks. Quantum Chromo-dynamics (QCD) is the modern theory of the interaction of quarks. This theory explains how quarks are held together via the strong interaction in particles known as hadrons. Hadrons consisting of three quarks are called baryons. Hadrons made up of a quark and an antiquark are called mesons. In his lecture, Carroll describes what happens when two hadrons collide and scatter to large angles. The violence of the collision causes the gluons that bind the quarks in a particular hadron to temporarily lose their grip on particular quarks. Quarks scramble toward renewed unity with other quarks, and they undergo rearrangement, which generally results in additional new particles. A two-body exclusive reaction has occurred when the same number of particles exist before and after the collisions. At large angles these exclusive reactions are very rare. The labels on the quarks known as flavor enable the experimenter to follow the history of individual quarks in detail during these exclusive reactions. Carroll describes the equipment used in the experiment to measure short distance, hard collisions at large angles. The collisions he discusses occur when a known beam of mesons or protons collide with a stationary proton target. Finally, Carroll summarizes what the experiments have shown from the study of exclusive reactions and what light some of their results shed on the theory of QCD.

  8. Submicron X-ray diffraction

    SciTech Connect

    MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

    2000-08-17

    At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.

  9. Exclusive production at CMS

    NASA Astrophysics Data System (ADS)

    Khakzad, Mohsen

    2017-03-01

    A search for exclusive or quasi-exclusive γγ → W+W- production, pp → p(∗)W+W-p(∗) → p(∗)μ±e∓p(∗), at √{s }=8 TeV (7 TeV) is reported using data corresponding to an integrated luminosity of 19.7 fb-1 (5.5fb-1), respectively. In this study, we look for any deviations that there might be from the Standard Model, and the results are used to set limits on the Anomalous Quartic Gauge Couplings. We also report a measurement of the exclusive production of pairs of charged pions in proton-proton collisions. The differential cross sections for π+π- pairs as a function of the pion pair invariant mass is measured and compared to several phenomenological predictions.

  10. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  11. Mutually Exclusive, Complementary, or . . .

    ERIC Educational Resources Information Center

    Schloemer, Cathy G.

    2016-01-01

    Whether students are beginning their study of probability or are well into it, distinctions between complementary sets and mutually exclusive sets can be confusing. Cathy Schloemer writes in this article that for years she used typical classroom examples but was not happy with the student engagement or the level of understanding they produced.…

  12. Mutually Exclusive, Complementary, or . . .

    ERIC Educational Resources Information Center

    Schloemer, Cathy G.

    2016-01-01

    Whether students are beginning their study of probability or are well into it, distinctions between complementary sets and mutually exclusive sets can be confusing. Cathy Schloemer writes in this article that for years she used typical classroom examples but was not happy with the student engagement or the level of understanding they produced.…

  13. Starch granule size distribution of hard red winter and hard red spring wheat: Its effects on mixing and breadmaking quality.

    USDA-ARS?s Scientific Manuscript database

    Starch was isolated from 98 hard red winter (HRW) wheat and 99 hard red spring (HRS) wheat. Granule size/volume distributions of the isolated starches were analyzed using a laser diffraction particle size analyzer. There were significant differences in the size distribution between HRW and HRS whe...

  14. Generalized parton distributions and exclusive processes

    SciTech Connect

    Guzey, Vadim

    2013-10-01

    In last fifteen years, GPDs have emerged as a powerful tool to reveal such aspects of the QCD structure of the nucleon as: - 3D parton correlations and distributions; - spin content of the nucleon. Further advances in the field of GPDs and hard exclusive processes rely on: - developments in theory and new methods in phenomenology such as new flexible parameterizations, neural networks, global QCD fits - new high-precision data covering unexplored kinematics: JLab at 6 and 12 GeV, Hermes with recoil detector, Compass, EIC. This slide-show presents: Nucleon structure in QCD, particularly hard processes, factorization and parton distributions; and a brief overview of GPD phenomenology, including basic properties of GPDs, GPDs and QCD structure of the nucleon, and constraining GPDs from experiments.

  15. Thermodynamic hardness and the maximum hardness principle

    NASA Astrophysics Data System (ADS)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  16. Thermodynamic hardness and the maximum hardness principle.

    PubMed

    Franco-Pérez, Marco; Gázquez, José L; Ayers, Paul W; Vela, Alberto

    2017-08-21

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T(-1)(I-A), where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  17. Fiber diffraction without fibers.

    PubMed

    Poon, H-C; Schwander, P; Uddin, M; Saldin, D K

    2013-06-28

    Postprocessing of diffraction patterns of completely randomly oriented helical particles, as measured, for example, in so-called "diffract-and-destroy" experiments with an x-ray free electron laser can yield "fiber diffraction" patterns expected of fibrous bundles of the particles. This will allow "single-axis alignment" to be performed computationally, thus obviating the need to do this by experimental means such as forming fibers and laser or flow alignment. The structure of such particles may then be found by either iterative phasing methods or standard methods of fiber diffraction.

  18. Robustness of Cantor diffractals.

    PubMed

    Verma, Rupesh; Sharma, Manoj Kumar; Banerjee, Varsha; Senthilkumaran, Paramasivam

    2013-04-08

    Diffractals are electromagnetic waves diffracted by a fractal aperture. In an earlier paper, we reported an important property of Cantor diffractals, that of redundancy [R. Verma et. al., Opt. Express 20, 8250 (2012)]. In this paper, we report another important property, that of robustness. The question we address is: How much disorder in the Cantor grating can be accommodated by diffractals to continue to yield faithfully its fractal dimension and generator? This answer is of consequence in a number of physical problems involving fractal architecture.

  19. Search for exclusive or semi-exclusive γγ production and observation of exclusive and semi-exclusive e+e- production in pp collisions at √{s}=7 TeV

    NASA Astrophysics Data System (ADS)

    Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Wagner, P.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Maes, T.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Staykova, Z.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Reis, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Vanelderen, L.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins, M.; De Jesus Damiao, D.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, S.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, S.; Zhu, B.; Zou, W.; Avila, C.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Khalil, S.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Azzolini, V.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sordini, V.; Tosi, S.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.; Klein, K.; Merz, J.; Ostapchuk, A.; Perieanu, A.; Raupach, F.

    2012-11-01

    A search for exclusive or semi-exclusive γγ production, pp → p(*) + γγ + p(*) (where p* stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive e+e- production, pp → p(*) + e+e- + p(*), in proton-proton collisions at √{s}=7 TeV, are presented. The analysis is based on a data sample corresponding to an integrated luminosity of 36 pb-1 recorded by the CMS experiment at the LHC at low instantaneous luminosities. Candidate γγ or e+e- events are selected by requiring the presence of two photons or a positron and an electron, each with transverse energy E T > 5 .5 GeV and pseudorapidity | η| < 2 .5, and no other particles in the region | η| < 5 .2. No exclusive or semi-exclusive diphoton candidates are found in the data. An upper limit on the cross section for the reaction pp → p(*) + γγ + p(*), within the above kinematic selections, is set at 1.18 pb at 95% confidence level. Seventeen exclusive or semi-exclusive dielectron candidates are observed, with an estimated background of 0 .85 ± 0 .28 (stat.) events, in agreement with the QED-based prediction of 16 .3 ± 1 .3 (syst.) events.[Figure not available: see fulltext.

  20. Phononic crystal diffraction gratings

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Herbison, Sarah; Declercq, Nico F.; Laude, Vincent

    2012-02-01

    When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends on the orientation of the phononic crystal. This work presents a combined experimental and theoretical study on the diffraction of bulk ultrasonic waves on the external surfaces of a 2D phononic crystal that consists of a triangular lattice of steel rods in a water matrix. The results of transmission experiments are compared with theoretical band structures obtained with the finite-element method. Angular spectrograms (showing frequency as a function of angle) determined from diffraction experiments are then compared with finite-element simulations of diffraction occurring on the surfaces of the crystal. The experimental results show that the diffraction that occurs on its external surfaces is highly frequency-dependent and has a definite relation with the Bloch modes of the phononic crystal. In particular, a strong influence of the presence of bandgaps and deaf bands on the diffraction efficiency is found. This observation opens perspectives for the design of efficient phononic crystal diffraction gratings.

  1. Diffractive Higgs Production from Intrinsic Heavy Flavors in the Proton

    SciTech Connect

    Brodsky, Stanley J.; Kopeliovich, Boris; Schmidt, Ivan; Soffer, Jacques

    2006-03-31

    We propose a novel mechanism for exclusive diffractive Higgs production pp {yields} pHp in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at high light-cone momentum fraction x has growing experimental and theoretical support. We also discuss the implications of this picture for exclusive diffractive quarkonium and other channels.

  2. Noise attenuation by a hard wedge-shaped barrier

    NASA Astrophysics Data System (ADS)

    Ouis, D.

    2003-04-01

    This paper is concerned with the problem of sound screening by a wedge-like barrier. The sound source is assumed to be point like, and the receiver is located in the shadow of the source sound field, so that according to geometrical optics only the field diffracted by the edge of the barrier is considered. First, for the hard wedge in space, three models are used for calculating the amplitude of the edge-diffracted field. These are the uniform theory of diffraction (UTD), the Hadden-Pierce model, both in the frequency domain, and the Biot-Tolstoy theory of diffraction which is a time domain formulation. It is first shown that even at relatively low frequencies, the frequency domain models perform quite satisfactorily as compared to the exact time domain theory. Hence, and due to its relative simplicity the UTD is proposed as an accurate calculation scheme for solving problems with edge diffraction by hard wedges. It is also proved from theoretical calculations that the amplitude of the edge-diffracted field increases for an increasing angle of the wedge, and consequently the hard half-plane gives the lowest field amplitude in the shadow zone. Some applications are then considered for evaluating the performance of a barrier on a flat ground, either completely hard or with mixed homogeneous boundary conditions. An improvement of the scheme for calculating the sound field in the all-hard case is achieved through considering the multiple diffraction, in this case only to the second order, between the top of the wedge barrier and its base. The results show that for usually occurring situations, increasing the angle of the hard wedge barrier affects negatively its efficiency through diminishing its insertion loss. These conclusions are also supported by the results of some experimental measurements conducted at a scale-model level.

  3. Social exclusion in finite populations

    NASA Astrophysics Data System (ADS)

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation.

  4. The rotating-crystal method in femtosecond X-ray diffraction.

    PubMed

    Freyer, B; Stingl, J; Zamponi, F; Woerner, M; Elsaesser, T

    2011-08-01

    We report the first implementation of the rotating-crystal method in femtosecond X-ray diffraction. Applying a pump-probe scheme with 100 fs hard X-ray probe pulses from a laser-driven plasma source, the novel technique is demonstrated by mapping structural dynamics of a photoexcited bismuth crystal via changes of the diffracted intensity on a multitude of Bragg reflections. The method is compared to femtosecond powder diffraction and to Bragg diffraction from a crystal with stationary orientation.

  5. Exclusion processes with avalanches.

    PubMed

    Bhat, Uttam; Krapivsky, P L

    2014-07-01

    In an exclusion process with avalanches, when a particle hops to a neighboring empty site which is adjacent to an island the particle on the other end of the island immediately hops, and if it joins another island this triggers another hop. There are no restrictions on the length of the islands and the duration of the avalanche. This process is well defined in the low-density region ρ < 1/2. We describe the nature of steady states (on a ring) and determine all correlation functions. For the asymmetric version of the process, we compute the steady state current, and we describe shock and rarefaction waves which arise in the evolution of the step-function initial profile. For the symmetric version, we determine the diffusion coefficient and examine the evolution of a tagged particle.

  6. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

    1999-01-01

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

  7. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

    1999-05-25

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

  8. The space-time structure of hard scattering processes

    SciTech Connect

    J.-M. Laget

    2004-09-01

    Recent studies of exclusive electroproduction of vector mesons at JLab make it possible for the first time to play with two independent hard scales: the virtuality Q{sup 2}2 of the photon, which sets the observation scale, and the momentum transfer t to the hadronic system, which sets the interaction scale. They reinforce the description of hard scattering processes in terms of few effective degrees of freedom relevant to the Jlab-Hermes energy range.

  9. Ordering of hard particles between hard walls

    NASA Astrophysics Data System (ADS)

    Chrzanowska, A.; Teixeira, P. I. C.; Ehrentraut, H.; Cleaver, D. J.

    2001-05-01

    The structure of a fluid of hard Gaussian overlap particles of elongation κ = 5, confined between two hard walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for the excluded volume kernel (Velasco E and Mederos L 1998 J. Chem. Phys. 109 2361) and solving the appropriate Euler-Lagrange equation entirely numerically, we have been able to extend our theoretical predictions into the nematic phase, which had up till now remained relatively unexplored due to the high computational cost. Simulation reveals a rich adsorption behaviour with increasing bulk density, which is described semi-quantitatively by the theory without any adjustable parameters.

  10. Exclusion performance and learning by exclusion in dogs.

    PubMed

    Zaine, Isabela; Domeniconi, Camila; de Rose, Julio C

    2016-05-01

    Responding by exclusion is a type of emergent repertoire in which an individual chooses an alternative by the apparent exclusion of other available alternatives. In this case it is possible to respond appropriately to an undefined stimulus (one that has not previously acquired discriminative functions) by excluding the defined alternatives. There is evidence of exclusion in humans and nonhuman animals, although learning as an outcome of exclusion does not always occur. This study aimed to investigate exclusion in visual simple discriminations and learning of new simple discriminations resulting from exclusion in four border collies. Subjects were trained to perform simple simultaneous discriminations between pairs of tridimensional objects, and were then tested for exclusion, novelty control and learning of new simple discriminations. All dogs successfully responded by exclusion, choosing an undefined stimulus displayed with an S-. For three dogs, it was possible to conclude that these previously undefined stimuli acquired S+ functions, documenting learning of new simple discriminations. However, this required up to four exposures to exclusion trials with each pair of stimuli.

  11. Fresnel Coherent Diffractive Imaging

    SciTech Connect

    Williams, G. J.; Quiney, H. M.; Dhal, B. B.; Tran, C. Q.; Nugent, K. A.; Peele, A. G.; Paterson, D.; Jonge, M. D. de

    2006-07-14

    We present an x-ray coherent diffractive imaging experiment utilizing a nonplanar incident wave and demonstrate success by reconstructing a nonperiodic gold sample at 24 nm resolution. Favorable effects of the curved beam illumination are identified.

  12. Fraunhofer Diffraction and Polarization.

    ERIC Educational Resources Information Center

    Fortin, E.

    1979-01-01

    Describes an experiment for the intermediate undergraduate optics laboratory designed to illustrate simultaneously some aspects of the phenomena of diffraction; interference, coherence, apodization, the Fresnel-Arago law; as well as of the interrelations between these concepts. (HM)

  13. Diffraction with CMS

    SciTech Connect

    Pereira, Antonio Vilela

    2011-07-15

    The observation of diffraction at LHC with the CMS detector at {radical}(s) = 900 and 2360 GeV is presented, along with a comparison of the data with the predictions of the PYTHIA and PHOJET generators.

  14. Diffraction as tunneling

    NASA Technical Reports Server (NTRS)

    Nussenzveig, H. M.; Wiscombe, W. J.

    1987-01-01

    A new approximation to the short-wavelength scattering amplitude from an impenetrable sphere is presented. It is uniform in the scattering angle and it is more accurate than previously known approximations (including Fock's theory of diffraction) by up to several orders of magnitude. It remains valid in the transition to long-wavelength scattering. It leads to a new physical picture of diffraction, as tunneling through an inertial barrier.

  15. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  16. Anomalous diffraction approximation limits

    NASA Astrophysics Data System (ADS)

    Videen, Gorden; Chýlek, Petr

    It has been reported in a recent article [Liu, C., Jonas, P.R., Saunders, C.P.R., 1996. Accuracy of the anomalous diffraction approximation to light scattering by column-like ice crystals. Atmos. Res., 41, pp. 63-69] that the anomalous diffraction approximation (ADA) accuracy does not depend on particle refractive index, but instead is dependent on the particle size parameter. Since this is at odds with previous research, we thought these results warranted further discussion.

  17. Inaccuracy in the treatment of multiple-order diffraction by secondary-edge-source methods.

    PubMed

    Summers, Jason E

    2013-06-01

    Existing secondary-edge-source methods based on the Biot-Tolstoy solution for diffraction from an infinite wedge compute multiple-order diffraction by cascading the integration over secondary sources used to determine first-order diffraction from the edge. It is demonstrated here that this approach errs in some important cases because it neglects slope-diffraction contributions. This error is illustrated by considering the case of an infinite slit in a thin, hard screen. Comparisons with measurements for this case and analytical solutions for the case of a circular aperture in a thin, hard screen are used as a basis to gauge the magnitude of the error.

  18. Holographic double diffraction of Higgs and the AdS/CFT graviton/Pomeron

    NASA Astrophysics Data System (ADS)

    Brower, Richard; Djuric, Marko; Tan, Chung-I.

    2014-11-01

    The holographic approach to double diffractive Higgs production is presented in terms of exchanging the AdS graviton/Pomeron. The goal is to provide a simple framework for central exclusive production from a dual strong coupling perspective.

  19. The dyadic diffraction coefficient for a curved edge

    NASA Technical Reports Server (NTRS)

    Kouyoumjian, R. G.; Pathak, P. H.

    1974-01-01

    A compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edge formed by perfectly conducting curved or plane surfaces is obtained. This diffraction coefficent remains valid in the transition regions adjacent to shadow and reflection boundaries, where the diffraction coefficients of Keller's original theory fail. The method is on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by plane, cylindrical, conical, and spherical waves. When the proper ray fixed coordinate system is introduced, the dyadic diffraction coefficient for the wedge is found to be the sum of only two dyads, and it is shown that this is also true for the dyadic diffraction coefficients of higher order edges. One dyad contains the acoustic soft diffraction coefficient; the other dyad contains the acoustic hard diffraction coefficient. The expressions for the acoustic wedge diffraction coefficients contain Fresnel integrals, which ensure that the total field is continuous at shadow and reflection boundaries. The diffraction coefficients have the same form for the different types of edge illumination; only the arguments of the Fresnel integrals are different. Since diffraction is a local phenomenon, and locally the curved edge structure is wedge shaped, this result is readily extended to the curved edge.

  20. Exclusive Processes in Quantum Chromodynamics

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; Peter Lepage, G.

    The following sections are included: * INTRODUCTION * NONRELATIVISTIC FORM FACTORS FOR HEAVY-QUARK MESONS * HADRONIC WAVEFUNCTIONS * DEFINITIONS * LIGHT-CONE BOUND-STATE EQUATIONS * GENERAL PROPERTIES OF LIGHT-CONE WAVEFUNCTIONS * RENORMALIZATION * CALCULATING * A PERTURBATIVE ANALYSIS * FACTORIZATION—LEADING ORDER ANALYSIS * THE QUARK DISTRIBUTION AMPLITUDE * DETERMINATION OF DISTRIBUTION AMPLITUDES * HIGHER ORDER ANALYSIS * COMPLICATIONS * How LARGE IS ASYMPTOTIC Q? * APPLICATIONS OF QCD TO THE PHENOMENOLOGY OF EXCLUSIVE REACTIONS * GENERAL FEATURES OF EXCLUSIVE PROCESSES IN QCD * ELECTROMAGNETIC FORM FACTORS * COMPARISON OF QCD SCALING WITH EXPERIMENT * EXCLUSIVE ANTI-PROTON PROTON ANNIHILATION PROCESSES * ADDITIONAL TESTS OF GLUON SPIN IN EXCLUSIVE PROCESSES * HADRONIC WAVEFUNCTION PHENOMENOLOGY * CALCULATING TH * THE PRE-QCD DEVELOPMENT OF EXCLUSIVE REACTIONS * EXCLUSIVE e+ e- ANNIHILATION PROCESSES * J/ψ DECAY TO HADRON PAIRS * THE π-ρ PUZZLE * FORM FACTOR ZEROS IN QCD * EXCLUSIVE γγ REACTIONS * QCD PROCESSES IN NUCLEI * EXCLUSIVE NUCLEAR REACTIONS - REDUCED AMPLITUDES * COLOR TRANSPARENCY * SPIN CORRELATIONS IN PROTON-PROTON SCATTERING * CONCLUSIONS * APPENDIX I BARYON FORM FACTORS AND EVOLUTION EQUATIONS * APPENDIX II LIGHT CONE QUANTIZATION AND PERTURBATION THEORY * APPENDIX III A NONPERTURBATIVE ANALYSIS OF EXCLUSIVE REACTIONS-DISCRETIZED LIGHT-CONE QUANTIZATION * ACKNOWLEDGEMENTS * REFERENCES

  1. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  2. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  3. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  4. Extension of the color glass condensate approach to diffractive reactions

    NASA Astrophysics Data System (ADS)

    Hentschinski, Martin; Weigert, Heribert; Schäfer, Andreas

    2006-03-01

    We present an evolution equation for the Bjorken x dependence of diffractive dissociation on hadrons and nuclei at high energies. We extend the formulation of Kovchegov and Levin by relaxing the factorization assumption used there. The formulation is based on a technique used by Weigert to describe interjet energy flow. The method can be naturally extended to other exclusive observables.

  5. The hard metal diseases

    SciTech Connect

    Cugell, D.W. )

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.66 references.

  6. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.

  7. Hard Photodisintegration of Proton Pairs in {sup 3}He

    SciTech Connect

    Piasetzky, Eli; Pomerantz, Ishay; Higinbotham, D.; Strauch, S.; Gilman, R.

    2008-10-13

    Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark-gluon degrees of freedom in high-momentum transfer exclusive reactions. We have now measured for the first time hard pp-pair disintegration in the reaction {gamma}{sup 3}He{yields}pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90 deg. c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.

  8. Hard Photo-disintegration of proton pairs in 3He

    SciTech Connect

    Piasetzky, Eliazer; Pomerantz, Ishay; Higinbotham, Douglas; Strauch, Steffen; Gilman, Ronald

    2008-11-01

    Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark-gluon degrees of freedom in high-momentum transfer exclusive reactions. We have now measured for the first time hard pp-pair disintegration in the reaction gamma 3He-->pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90 deg. c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.

  9. Diffraction light analysis method for a diffraction grating imaging lens.

    PubMed

    Ando, Takamasa; Korenaga, Tsuguhiro; Suzuki, Masa-aki; Tanida, Jun

    2014-04-10

    We have developed a new method to analyze the amount and distribution of diffraction light for a diffraction grating lens. We have found that diffraction light includes each-order diffraction light and striped diffraction light. In this paper, we describe characteristics of striped diffraction light and suggest a way to analyze diffraction light. Our analysis method, which considers the structure of diffraction grating steps, can simulate the aberrations of an optical system, each-order diffraction light, and striped diffraction light simultaneously with high accuracy. A comparison between the simulation and experimental results is presented, and we also show how our analysis method can be used to optimize a diffraction grating lens with low flare light.

  10. Exclusive vector meson production at HERA from QCD with saturation

    SciTech Connect

    Marquet, C.; Peschanski, R.; Soyez, G.

    2007-08-01

    Following recent predictions that the geometric scaling properties of deep inelastic scattering data in inclusive {gamma}*p collisions are expected also in exclusive diffractive processes, we investigate the diffractive production of vector mesons. Using analytic results in the framework of the Balitsky-Kovchegov (BK) equation at nonzero momentum transfer, we extend to the nonforward amplitude a QCD-inspired forward saturation model including charm, following the theoretical predictions for the momentum transfer dependence of the saturation scale. We obtain a good fit to the available HERA data and make predictions for deeply virtual Compton scattering measurements.

  11. QCD Aspects of Exclusive B Decays

    SciTech Connect

    Brodsky, Stanley J.

    2001-04-04

    Exclusive B decays can be factorized as convolutions of hard scattering amplitudes involving the weak interaction with universal hadron distribution amplitudes, thus providing a new QCD-based phenomenology. In addition, semi-leptonic decay amplitudes can be computed exactly in terms of the diagonal and off-diagonal {Delta} = 2 overlap of hadronic light-cone wavefunctions. I review these formalisms and the essential QCD ingredients. A canonical form of the light-cone wavefunctions, valid at low values of the transverse momenta, is presented. The existence of intrinsic charm Fock states in the B meson wavefunction can enhance the production of final states of B-decay with three charmed quarks, such as B {yields} J/{psi}D, as well as lead to the breakdown of the CKM hierarchy.

  12. Deeply exclusive processes and generalized parton distributions

    SciTech Connect

    Marc Vanderhaegen

    2005-02-01

    We discuss how generalized parton distributions (GPDs) enter into hard exclusive processes, and focuses on the links between GPDs and elastic nucleon form factors. These links, in the form of sum rules, represent powerful constraints on parameterizations of GPDs. A Regge parameterization for the GPDs at small momentum transfer -t is extended to the large-t region and it is found to catch the basic features of proton and neutron electromagnetic form factor data. This parameterization allows to estimate the quark contribution to the nucleon spin. It is furthermore discussed how these GPDs at large-t enter into two-photon exchange processes and resolve the discrepancy between Rosenbluth and polarization experiments of elastic electron nucleon scattering.

  13. Multipath analysis diffraction calculations

    NASA Technical Reports Server (NTRS)

    Statham, Richard B.

    1996-01-01

    This report describes extensions of the Kirchhoff diffraction equation to higher edge terms and discusses their suitability to model diffraction multipath effects of a small satellite structure. When receiving signals, at a satellite, from the Global Positioning System (GPS), reflected signals from the satellite structure result in multipath errors in the determination of the satellite position. Multipath error can be caused by diffraction of the reflected signals and a method of calculating this diffraction is required when using a facet model of the satellite. Several aspects of the Kirchhoff equation are discussed and numerical examples, in the near and far fields, are shown. The vector form of the extended Kirchhoff equation, by adding the Larmor-Tedone and Kottler edge terms, is given as a mathematical model in an appendix. The Kirchhoff equation was investigated as being easily implemented and of good accuracy in the basic form, especially in phase determination. The basic Kirchhoff can be extended for higher accuracy if desired. A brief discussion of the method of moments and the geometric theory of diffraction is included, but seems to offer no clear advantage in implementation over the Kirchhoff for facet models.

  14. Exact results for the one dimensional asymmetric exclusion model

    NASA Astrophysics Data System (ADS)

    Derrida, B.; Evans, M. R.; Hakim, V.; Pasquier, V.

    1993-11-01

    The asymmetric exclusion model describes a system of particles hopping in a preferred direction with hard core repulsion. These particles can be thought of as charged particles in a field, as steps of an interface, as cars in a queue. Several exact results concerning the steady state of this system have been obtained recently. The solution consists of representing the weights of the configurations in the steady state as products of non-commuting matrices.

  15. Newton's diffraction measurements

    NASA Astrophysics Data System (ADS)

    Nauenberg, Michael

    2004-05-01

    This year marks the tercentenary of the publication of Newton's Opticks which contains his celebrated theory and experiments of light and colors as it evolved from the first published version in 1672. It is still fairly unknown, however, that in this book Newton also reported his experiments on diffraction fringes obtained from various "slender" objects placed in a beam of sunlight. These experiments posed an insurmountable difficulty to Newton's corpuscular theory of light, which failed to account for his observations. This failure explains the long delay in the publication of this book. In my talk I will compare Newton's experimental results on diffraction with the predictions of Fresnel's wave theory to demonstrate that his measurements were remarkable accurate. Eventually these measurements paved the way for Young's correct explanation of the diffraction fringes as a wave interference phenomenon.

  16. Evaluating Alternatives to Exclusive "He."

    ERIC Educational Resources Information Center

    Todd-Mancillas, William R.

    A study was conducted to determine the effects on reading comprehension of the use of the exclusive pronoun "he" and more or less contrived alternatives. Subjects, 358 students enrolled in an introduction to human communication at a large northeastern university, read three different forms of the same essay. One essay form exclusively used "he,"…

  17. The Goos-Hänchen effect at Bragg diffraction.

    PubMed

    Tamasaku, Kenji; Ishikawa, Tetsuya

    2002-07-01

    The strong incident-angle dependence of the phase of complex reflectivity causes a shift of the reflected beam from the geometrically expected path. This effect, known as the Goos-Hänchen effect in the visible region, was observed for Bragg-case diffraction in the hard X-ray region. The shift was found to be in good agreement with the theory.

  18. Dynamic hardness of metals

    NASA Astrophysics Data System (ADS)

    Liang, Xuecheng

    Dynamic hardness (Pd) of 22 different pure metals and alloys having a wide range of elastic modulus, static hardness, and crystal structure were measured in a gas pulse system. The indentation contact diameter with an indenting sphere and the radius (r2) of curvature of the indentation were determined by the curve fitting of the indentation profile data. r 2 measured by the profilometer was compared with that calculated from Hertz equation in both dynamic and static conditions. The results indicated that the curvature change due to elastic recovery after unloading is approximately proportional to the parameters predicted by Hertz equation. However, r 2 is less than the radius of indenting sphere in many cases which is contradictory to Hertz analysis. This discrepancy is believed due to the difference between Hertzian and actual stress distributions underneath the indentation. Factors which influence indentation elastic recovery were also discussed. It was found that Tabor dynamic hardness formula always gives a lower value than that directly from dynamic hardness definition DeltaE/V because of errors mainly from Tabor's rebound equation and the assumption that dynamic hardness at the beginning of rebound process (Pr) is equal to kinetic energy change of an impact sphere over the formed crater volume (Pd) in the derivation process for Tabor's dynamic hardness formula. Experimental results also suggested that dynamic to static hardness ratio of a material is primarily determined by its crystal structure and static hardness. The effects of strain rate and temperature rise on this ratio were discussed. A vacuum rotating arm apparatus was built to measure Pd at 70, 127, and 381 mum sphere sizes, these results exhibited that Pd is highly depended on the sphere size due to the strain rate effects. P d was also used to substitute for static hardness to correlate with abrasion and erosion resistance of metals and alloys. The particle size effects observed in erosion were

  19. Single molecule diffraction.

    PubMed

    Spence, J C H; Doak, R B

    2004-05-14

    For solving the atomic structure of organic molecules such as small proteins which are difficult to crystallize, the use of a jet of doped liquid helium droplets traversing a continuous high energy electron beam is proposed as a means of obtaining electron diffraction patterns (serial crystallography). Organic molecules (such as small proteins) within the droplet (and within a vitreous ice jacket) may be aligned by use of a polarized laser beam. Iterative methods for solving the phase problem are indicated. Comparisons with a related plan for pulsed x-ray diffraction from single proteins in a molecular beam are provided.

  20. Biopolymer holographic diffraction gratings

    NASA Astrophysics Data System (ADS)

    Savić Šević, Svetlana; Pantelić, Dejan

    2008-03-01

    Surface-relief diffraction gratings are holographically recorded in dextran sensitized with ammonium dichromate (DCD). DCD was exposed with single-frequency 200 mW diode pumped ND-YAG laser, at 532 nm. The diffraction grating profiles were analyzed by atomic force microscopy (AFM). It was found that different surface profiles could be obtained. Gratings with 330 lines/mm spatial frequencies were made. Existence of higher harmonics in Fourier Transform of non-sinusoidal profiles shows that DCD is capable of recording spatial frequencies up to 1320 lines/mm (four times fundamental frequency). The measured maximum relief depth of the DCD grating is 402 nm.

  1. Inference by Exclusion in Goffin Cockatoos (Cacatua goffini)

    PubMed Central

    O’Hara, Mark; Auersperg, Alice M. I.; Bugnyar, Thomas; Huber, Ludwig

    2015-01-01

    Inference by exclusion, the ability to base choices on the systematic exclusion of alternatives, has been studied in many nonhuman species over the past decade. However, the majority of methodologies employed so far are hard to integrate into a comparative framework as they rarely use controls for the effect of neophilia. Here, we present an improved approach that takes neophilia into account, using an abstract two-choice task on a touch screen, which is equally feasible for a large variety of species. To test this approach we chose Goffin cockatoos (Cacatua goffini), a highly explorative Indonesian parrot species, which have recently been reported to have sophisticated cognitive skills in the technical domain. Our results indicate that Goffin cockatoos are able to solve such abstract two-choice tasks employing inference by exclusion but also highlight the importance of other response strategies. PMID:26244692

  2. Exclusive Photoproduction of ϒ:. from Hera to Tevatron

    NASA Astrophysics Data System (ADS)

    Rybarska, Anna; Schäfer, Wolfgang; Szczurek, Antoni

    The amplitude for photoproduction γp → ϒp is calculated in a pQCD k⊥-factorization approach. The total cross section for diffractive ϒs is compared to recent HERA data. The amplitude is used to predict the cross section for exclusive pbar p-> pΥ (1S, 2S)bar p proces in hadronic reactions at Tevatron energies. We also included absorption effects.

  3. Estimating diffractive Higgs boson production at LHC from HERA data

    NASA Astrophysics Data System (ADS)

    Graudenz, D.; Veneziano, G.

    1996-02-01

    Using a recently proposed factorization hypothesis for semi-inclusive hard processes in QCD, one can study, in principle, the diffractive production of the Standard Model Higgs boson at LHC using only, as input, ep diffractive hard-processes data of the type recently collected and analyzed by the H1 and ZEUS collaborations at HERA. While waiting for a more precise and complete set of data, we combine here the existing data with a simple Pomeron-exchange picture and find a large spread in the Higgs boson production cross section, depending on the input parametrization of the Pomeron's parton content. In particular, if the Pomeron gluon density f {g}/{p}(β) is peaked at large β for small scales, single diffractive events will represent a sizeable fraction of all produced Higgs bosons with an expected better-than-average signal-to-background ratio.

  4. Calculating cellulose diffraction patterns

    USDA-ARS?s Scientific Manuscript database

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  5. DIFFRACTION FROM MODEL CRYSTALS

    USDA-ARS?s Scientific Manuscript database

    Although calculating X-ray diffraction patterns from atomic coordinates of a crystal structure is a widely available capability, calculation from non-periodic arrays of atoms has not been widely applied to cellulose. Non-periodic arrays result from modeling studies that, even though started with at...

  6. Diffract, then destroy

    NASA Astrophysics Data System (ADS)

    Ball, Philip

    2016-09-01

    A new implementation of X-ray diffraction using free-electron lasers can take snapshots of biological molecules that are inaccessible via X-ray crystallography. As Philip Ball reports, the technique can even be used to create stop-motion films of dynamic molecular processes

  7. Inclusive diffraction at HERA

    SciTech Connect

    Favart, Laurent

    2011-07-15

    Results are reported on recent measurements, performed by the H1 and ZEUS Collaborations, of the cross section of the diffractive deep-inelastic process ep{yields}eXp using different experimental methods. In particular, first results using the Very Forward Proton Spectrometer of H1 are discussed.

  8. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  9. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  10. Radiation from hard objects

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    The inference of the diameter of hard objects is insensitive to radiation efficiency. Deductions of radiation efficiency from observations are very sensitive - possibly overly so. Inferences of the initial velocity and trajectory vary similarly, and hence are comparably sensitive.

  11. Central exclusive production in the STAR experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Sikora, Rafal

    2017-03-01

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) performs studies of diffractive processes with the focus on the exclusive production of particles in central range of rapidity. In 2015 STAR collected 18 pb-1 of data in polarized proton+proton collisions at √{s }=200 GeV to measure Central Exclusive Production (CEP) process pp → pX p through Double Pomeron Exchange (DPE) mechanism. The intact protons moving inside the RHIC beampipe after the collision were measured in silicon strip detectors (SSD), which were placed in the Roman Pot vessels. This enables full control over interaction kinematics and verification of the exclusivity of the reaction by measuring the total (missing) transverse momenta of all final state particles: the central diffractive system in the Time Projection Chamber (TPC) and the forward protons in the Roman Pots. With the use of ionization energy loss in the TPC, dE/dx, it was possible to discriminate various production channels in pp → pX p reaction. This paper presents results on exclusive production of two charged particles (π+π- and K+ K-) in mid-rapidity region, -1 < η < 1, with small squared four-momentum transfer of forward protons, 0.03 < -t < 0.3 (GeV/c)2, obtained using 2.5% of full statistics.

  12. Exclusive channels in semi-inclusive production of pions and kaons

    SciTech Connect

    Markus Diehl; Wolfgang Kugler; Andreas Schaefer; Christian Weiss

    2005-06-01

    We investigate the role of exclusive channels in semi-inclusive electroproduction of pions and kaons. Using the QCD factorization theorem for hard exclusive processes we evaluate the cross sections for exclusive pseudoscalar and vector meson production in terms of generalized parton distributions and meson distribution amplitudes. We investigate the uncertainties arising from the modeling of the nonperturbative input quantities. Combining these results with available experimental data, we compare the cross sections for exclusive channels to that obtained from quark fragmentation in semi-inclusive deep inelastic scattering. We find that rho0 production is the only exclusive channel with significant contributions to semi-inclusive pion production at large z and moderate Q2. The corresponding contribution to kaon production from the decay of exclusively produced phi and Kstar is rather small.

  13. Diffractive and total pp cross sections at the LHC and beyond

    SciTech Connect

    Goulianos, Konstantin

    2011-07-15

    Results on factorization breaking in soft and hard hadron-hadron collisions, photo-production and deep inelastic scattering exhibit a universal behavior in a renormalization model where diffraction is mediated by a saturated colorless exchange with vacuum quantum numbers. Using this model, diffractive and total cross sections are predicted for LHC energies.

  14. 78 FR 55687 - Notice of Intent To Grant an Exclusive, Partially Exclusive or Non-Exclusive License of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... prospective exclusive, partially exclusive, or non-exclusive license of the following U.S. Patent Application... business at 201 Ruther Drive, Suite 3, Newark, DE 19711. DATES: Written objections must be filed not later...

  15. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  16. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  17. Central Diffraction in ALICE

    SciTech Connect

    Schicker, R.

    2011-07-15

    The ALICE experiment consists of a central barrel in the pseudorapidity range -0.9<{eta}<0.9 and of additional detectors covering about 3 units of pseudorapidity on either side of the central barrel. Such a geometry allows the tagging of single and double gap events. The status of the analysis of such diffractive events in proton-proton collisions at {radical}(s) = 7 TeV is presented.

  18. Diffraction before destruction

    PubMed Central

    Chapman, Henry N.; Caleman, Carl; Timneanu, Nicusor

    2014-01-01

    X-ray free-electron lasers have opened up the possibility of structure determination of protein crystals at room temperature, free of radiation damage. The femtosecond-duration pulses of these sources enable diffraction signals to be collected from samples at doses of 1000 MGy or higher. The sample is vaporized by the intense pulse, but not before the scattering that gives rise to the diffraction pattern takes place. Consequently, only a single flash diffraction pattern can be recorded from a crystal, giving rise to the method of serial crystallography where tens of thousands of patterns are collected from individual crystals that flow across the beam and the patterns are indexed and aggregated into a set of structure factors. The high-dose tolerance and the many-crystal averaging approach allow data to be collected from much smaller crystals than have been examined at synchrotron radiation facilities, even from radiation-sensitive samples. Here, we review the interaction of intense femtosecond X-ray pulses with materials and discuss the implications for structure determination. We identify various dose regimes and conclude that the strongest achievable signals for a given sample are attained at the highest possible dose rates, from highest possible pulse intensities. PMID:24914146

  19. Polychromatic diffraction contrast tomography

    SciTech Connect

    King, A.; Reischig, P.; Adrien, J.; Peetermans, S.; Ludwig, W.

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  20. Diffractive Higgs boson production at the Fermilab Tevatron and the CERN Large Hadron Collider.

    PubMed

    Enberg, R; Ingelman, G; Kissavos, A; Tîmneanu, N

    2002-08-19

    Improved possibilities to find the Higgs boson in diffractive events, having less hadronic activity, depend on whether the cross section is large enough. Based on the soft color interaction models that successfully describe diffractive hard scattering at DESY HERA and the Fermilab Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the CERN Large Hadron Collider.

  1. Prospects for diffractive physics with the CDF forward detectors at the Tevatron

    SciTech Connect

    M. Gallinaro

    2002-07-09

    The Forward Detector upgrade project at CDF is designed to enhance the capabilities for studies of diffractive physics at the Tevatron during Run II. Studies of hard diffraction and very forward physics are some of the topics that can be addressed in the next few years at the Tevatron. The program for diffractive physics, including the detectors and their commissioning, is discussed here. All the detectors have been installed and are presently collecting data.

  2. Hard X-ray Laue monochromator

    NASA Astrophysics Data System (ADS)

    Kocharyan, V. R.; Gogolev, A. S.; Kiziridi, A. A.; Batranin, A. V.; Muradyan, T. R.

    2016-06-01

    Experimental studies of X-ray diffraction from reflecting atomic planes (10¯11) of X-cut quartz single crystal in Laue geometry influenced by the temperature gradient were carried out. It is shown that by using the temperature gradient it is possible to reflect a hard X- ray beam with photon energy near the 100 keV with high efficiency. It has been experimentally proved that the intensity of the reflected beam can be increased by more than order depending on the value of the temperature gradient.

  3. A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface

    NASA Technical Reports Server (NTRS)

    Kouyoumjian, R. G.; Pathak, P. H.

    1974-01-01

    A compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edge formed by perfectly conducting curved or plane surfaces is obtained. This diffraction coefficient remains valid in the transition regions adjacent to shadow and reflection boundaries, where the diffraction coefficients of Keller's original theory fail. Our method is based on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by plane, cylindrical, conical, and spherical waves. When the proper ray-fixed coordinate system is introduced, the dyadic diffraction coefficient for the wedge is found to be the sum of only two dyads, and it is shown that this is also true for the dyadic diffraction coefficients of higher order edges. One dyad contains the acoustic soft diffraction coefficient; the other dyad contains the acoustic hard diffraction coefficient. The expressions for the acoustic wedge diffraction coefficients contain Fresnel integrals, which ensure that the total field is continuous at shadow and reflection boundaries.

  4. Softeners for hardness removal.

    PubMed

    Shetty, Rashma; Manjunath, N T; Babu, B T Suresh

    2005-10-01

    The depletion of water resources, both surface and subsurface and deterioration of water quality made researchers and policy makers to think of the possible remedies to make water sources potable / wholesome. There is a need to address the problems of hardness and fluoride in subsurface water on priority basis. In this direction, bench scale studies were conducted to evaluate the performance of water softeners. Indepth studies were carried out at University B.D.T College of Engineering, Davangere, Karnataka, to assess the performance of bench scale softeners of D to H ratio 1:2, 1:3, 1:4 in removing hardness of varied concentrations from both synthetic and natural water samples. Studies revealed that irrespective of D to H ratio of softeners, the waters having hardness concentration up to 1000 mg/l can be treated to the same degree (81.68% and above). The findings of regeneration studies and cost economics are also summarized in this paper.

  5. Interior impedance wedge diffraction with surface waves

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Griesser, Timothy

    1988-01-01

    The exact impedance wedge solution is evaluated asymptotically using the method of steepest descents for plane wave illumination at normal incidence. Uniform but different impedances on each face are considered for both soft and hard polarizations. The asymptotic solution isolates the incident, singly reflected, multiply reflected, diffracted, and surface wave fields. Multiply reflected fields of any order are permitted. The multiply reflected fields from the exact solution are written as ratios of auxiliary Maliuzhinets functions, whereas a geometrical analysis gives the reflected fields as products of reflection coefficients. These two representations are shown to be identical in magnitude, phase and the angular range over which they exist. The diffracted field includes four Fresnel transition functions as in the perfect conductor case, and the expressions for the appropriate discontinuities at the shadow boundaries are presented. The surface wave exists over a finite angular range and only for certain surface impedances. A surface wave transition field is included to retain continuity. Computations are presented for interior wedge diffractions although the formulation is valid for both exterior and interior wedges.

  6. Diffraction of a Laser Beam.

    ERIC Educational Resources Information Center

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  7. Diffractive Alvarez lens

    SciTech Connect

    Barton, Ian M.; Dixit, Sham N.; Summers, Leslie J.; Thompson, Charles A.; Avicola, Kenneth; Wilhelmsen, Julia

    2000-01-01

    A diffractive Alvarez lens is demonstrated that consists of two separate phase plates, each having complementary 16-level surface-relief profiles that contain cubic phase delays. Translation of these two components in the plane of the phase plates is shown to produce a variable astigmatic focus. Both spherical and cylindrical phase profiles are demonstrated with good accuracy, and the discrete surface-relief features are shown to cause less than {lambda}/10 wave-front aberration in the transmitted wave front over a 40 mmx80 mm region. (c) 2000 Optical Society of America.

  8. Diffraction from materials

    SciTech Connect

    Schwartz, L.H.; Cohen, J.B.

    1987-01-01

    This is a completely revised second edition and is intended as a text in diffraction. The book presents elementary topics on scattering and crystallography and expands on concepts in later chapters which focus on defects in solids, scattering from perfect solids, and crystal structure determination. The first half of the book may be used as an introductory text for juniors or seniors in college, while the second half is suitable for a graduate-level course or for use as a monograph. The new edition simplifies the introduction to crystallography, introduces concepts required by the advent of synchrotron radiation and pulsed reaction sources, and updates the subject matter dealing with defects in solids.

  9. Transurethral Ultrasound Diffraction Tomography

    DTIC Science & Technology

    2007-03-01

    transmitter. These are then 7 Fourier transformed into the frequency domain data. The clock rate is 33 MHz, and the FFT is performed after 1536 time...B. Yazgan and O.K. Ersoy, Multistage parallel algorithm for diffraction tomography, Applied Optica , vol. 34, pp, 1426-1431, 1995. [9] J. Wiskin, D.T...J1k0a2. Note that Eq. 34 reflects the well-known fact that in the Born approxi- mation the Fourier frequencies of the object are confined within a

  10. Electron diffraction from cylindrical nanotubes

    SciTech Connect

    Qin, L.C. )

    1994-09-01

    Electron diffraction intensities from cylindrical objects can be conveniently analyzed using Bessel functions. Analytic formulas and geometry of the diffraction patterns from cylindrical carbon nanotubes are presented in general forms in terms of structural parameters, such as the pitch angle and the radius of a tubule. As an example the Fraunhofer diffraction pattern from a graphitic tubule of structure [18,2] has been simulated to illustrate the characteristics of such diffraction patterns. The validity of the projection approximation is also discussed.

  11. Diffraction-Based Optical Switch

    NASA Technical Reports Server (NTRS)

    Sperno, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

    2005-01-01

    Method and system for controllably redirecting a light beam, having a central wavelength lambda, from a first light-receiving site to a second light-receiving site. A diffraction grating is attached to or part of a piezoelectric substrate, which is connected to one or two controllable voltage difference sources. When a substrate voltage difference is changed and the diffraction grating length in each of one or two directions is thereby changed, at least one of the diffraction angle, the diffraction order and the central wavelength is controllably changed. A diffracted light beam component, having a given wavelength, diffraction angle and diffraction order, that is initially received at a first light receiving site (e.g., a detector or optical fiber) is thereby controllably shifted or altered and can be received at a second light receiving site. A polynomially stepped, chirped grating is used in one embodiment. In another embodiment, an incident light beam, having at least one of first and second wavelengths, lambda1 and lambda2, is received and diffracted at a first diffraction grating to provide a first diffracted beam. The first diffracted beam is received and diffracted at a second diffraction grating to produce a second diffracted beam. The second diffracted beam is received at a light-sensitive transducer, having at least first and second spaced apart light detector elements that are positioned so that, when the incident light beam has wavelength lambda1 or lambda2 (lambda1 not equal to lambda2), the second diffracted beam is received at the first element or at the second element, respectively; change in a selected physical parameter at the second grating can also be sensed or measured. A sequence of spaced apart light detector elements can be positioned along a linear or curvilinear segment with equal or unequal spacing.

  12. Design the diffractive optical element with large diffraction angle

    NASA Astrophysics Data System (ADS)

    Pang, Hui; Yin, Shaoyun; Zheng, Guoxing; Deng, Qiling; Shi, Lifang; Du, Chunlei

    2014-11-01

    In this paper, a quite effective method is proposed for designing the diffractive optical element (DOE) to generate a pattern with large diffraction angle. Through analyze the difference between the non-paraxial Rayleigh Sommerfeld integral and the paraxial Fraunhofer diffraction integral, we modify the desired output intensity distribution with coordinate transformation and intensity adjustment. Then the paraxial Fraunhofer diffraction integral can be used to design the DOE, which adopts the fast-Fourier-transform (FFT) algorithm to accelerate the computation. To verify our method, the simulation and the experiments are taken. And the result shows that our method can effectively rectify the pillow distortion and can achieve the exact diffraction angle.

  13. Aberrations of diffracted wave fields. II. Diffraction gratings.

    PubMed

    Mahajan, V N

    2000-12-01

    The Rayleigh-Sommerfeld theory is applied to diffraction of a spherical wave by a grating. The grating equation is obtained from the aberration-free diffraction pattern, and its aberrations are shown to be the same as the conventional aberrations obtained by using Fermat's principle. These aberrations are shown to be not associated with the diffraction process. Moreover, it is shown that the irradiance distribution of a certain diffraction order is the Fraunhofer diffraction pattern of the grating aperture as a whole aberrated by the aberration of that order.

  14. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  15. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  16. Running in Hard Times

    ERIC Educational Resources Information Center

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  17. Running in Hard Times

    ERIC Educational Resources Information Center

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  18. CSI: Hard Drive

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  19. Spectral diffraction efficiency characterization of broadband diffractive optical elements.

    SciTech Connect

    Choi, Junoh; Cruz-Cabrera, Alvaro Augusto; Tanbakuchi, Anthony

    2013-03-01

    Diffractive optical elements, with their thin profile and unique dispersion properties, have been studied and utilized in a number of optical systems, often yielding smaller and lighter systems. Despite the interest in and study of diffractive elements, the application has been limited to narrow spectral bands. This is due to the etch depths, which are optimized for optical path differences of only a single wavelength, consequently leading to rapid decline in efficiency as the working wavelength shifts away from the design wavelength. Various broadband diffractive design methodologies have recently been developed that improve spectral diffraction efficiency and expand the working bandwidth of diffractive elements. We have developed diffraction efficiency models and utilized the models to design, fabricate, and test two such extended bandwidth diffractive designs.

  20. Radial reflection diffraction tomography

    NASA Astrophysics Data System (ADS)

    Lehman, Sean K.; Norton, Stephen J.

    2004-10-01

    A wave-based tomographic imaging algorithm based upon a single rotating radially outward oriented transducer is developed. At successive angular locations at a fixed radius, the transducer launches a primary field and collects the backscattered field in a ``pitch/catch'' operation. The hardware configuration, operating mode, and data collection method are identical to that of most medical intravascular ultrasound (IVUS) systems. IVUS systems form images of the medium surrounding the probe based upon ultrasonic B scans, using a straight-ray model of sound propagation. The goal of this research is to develop a wave-based imaging algorithm using diffraction tomography techniques. Given the hardware configuration and the imaging method, this system is referred to as ``radial reflection diffraction tomography.'' Two hardware configurations are considered: a multimonostatic mode using a single transducer as described above, and a multistatic mode consisting of a single transmitter and an aperture formed by multiple receivers. In this latter case, the entire source/receiver aperture rotates about the fixed radius. Practically, such a probe is mounted at the end of a catheter or snaking tube that can be inserted into a part or medium with the goal of forming images of the plane perpendicular to the axis of rotation. An analytic expression for the multimonostatic inverse is derived, but ultimately the new Hilbert space inverse wave (HSIW) algorithm is used to construct images using both operating modes. Applications include improved IVUS imaging, bore hole tomography, and nondestructive evaluation (NDE) of parts with existing access holes. .

  1. Radial Reflection Diffraction Tomography

    SciTech Connect

    Lehman, S K; Norton, S J

    2003-10-10

    We develop a wave-based tomographic imaging algorithm based upon a single rotating radially outward oriented transducer. At successive angular locations at a fixed radius, the transducer launches a primary field and collects the backscattered field in a ''pitch/catch'' operation. The hardware configuration, operating mode, and data collection method is identical to that of most medical intravascular ultrasound (IVUS) systems. IVUS systems form images of the medium surrounding the probe based upon ultrasonic B-scans, using a straight-ray model of sound propagation. Our goal is to develop a wave-based imaging algorithm using diffraction tomography techniques. Given the hardware configuration and the imaging method, we refer to this system as ''radial reflection diffraction tomography.'' We consider two hardware configurations: a multimonostatic mode using a single transducer as described above, and a multistatic mode consisting of a single transmitter and an aperture formed by multiple receivers. In this latter case, the entire source/receiver aperture rotates about the fixed radius. Practically, such a probe is mounted at the end of a catheter or snaking tube that can be inserted into a part or medium with the goal of forming images of the plane perpendicular to the axis of rotation. We derive an analytic expression for the multimonostatic inverse but ultimately use the new Hilbert space inverse wave (HSIW) algorithm to construct images using both operating modes. Applications include improved IVUS imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts with existing access holes.

  2. Diffraction Gratings for High-Intensity Laser Applications

    SciTech Connect

    Britten, J

    2008-01-23

    The scattering of light into wavelength-dependent discrete directions (orders) by a device exhibiting a periodic modulation of a physical attribute on a spatial scale similar to the wavelength of light has been the subject of study for over 200 years. Such a device is called a diffraction grating. Practical applications of diffraction gratings, mainly for spectroscopy, have been around for over 100 years. The importance of diffraction gratings in spectroscopy for the measurement of myriad properties of matter can hardly be overestimated. Since the advent of coherent light sources (lasers) in the 1960's, applications of diffraction gratings in spectroscopy have further exploded. Lasers have opened a vast application space for gratings, and apace, gratings have enabled entirely new classes of laser systems. Excellent reviews of the history, fundamental properties, applications and manufacturing techniques of diffraction gratings up to the time of their publication can be found in the books by Hutley (1) and more recently Loewen and Popov (2). The limited scope of this chapter can hardly do justice to such a comprehensive subject, so the focus here will be narrowly limited to characteristics required for gratings suitable for high-power laser applications, and methods to fabricate them. A particular area of emphasis will be on maximally-efficient large-aperture gratings for short-pulse laser generation.

  3. Unemployment: Hard-Core or Hard-Shell?

    ERIC Educational Resources Information Center

    Lauer, Robert H.

    1972-01-01

    The term hard-core'' makes the unemployed culpable; the term hard shell'' shifts the burden to the employer, and the evidence from the suburban plant indicates that a substantial part of the problem must lie there. (DM)

  4. Overcoming Exclusion through Adult Learning.

    ERIC Educational Resources Information Center

    Nash, Ian; Walshe, John

    Strategies for overcoming exclusion through adult learning were identified through case studies of 19 initiatives in the following countries: Belgium; Mexico; the Netherlands; Norway; Portugal; and the United Kingdom. The study programs involved a diverse array of formal, nonformal, and informal public sector, community, and enterprise-based…

  5. University Ranking as Social Exclusion

    ERIC Educational Resources Information Center

    Amsler, Sarah S.; Bolsmann, Chris

    2012-01-01

    In this article we explore the dual role of global university rankings in the creation of a new, knowledge-identified, transnational capitalist class and in facilitating new forms of social exclusion. We examine how and why the practice of ranking universities has become widely defined by national and international organisations as an important…

  6. Exclusive processes in quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.; Lepage, G.P.

    1981-06-01

    Large momentum transfer exclusive processes and the short distance structure of hadronic wave functions can be systematically analyzed within the context of perturbative QCD. Predictions for meson form factors, two-photon processes ..gamma gamma.. ..-->.. M anti M, hadronic decays of heavy quark systems, and a number of other related QCD phenomena are reviewed.

  7. University Ranking as Social Exclusion

    ERIC Educational Resources Information Center

    Amsler, Sarah S.; Bolsmann, Chris

    2012-01-01

    In this article we explore the dual role of global university rankings in the creation of a new, knowledge-identified, transnational capitalist class and in facilitating new forms of social exclusion. We examine how and why the practice of ranking universities has become widely defined by national and international organisations as an important…

  8. Multilayer diffraction grating

    DOEpatents

    Barbee, T.W. Jr.

    1990-04-10

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  9. Multilayer diffraction grating

    DOEpatents

    Barbee, Jr., Troy W.

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  10. Birefringent coherent diffraction imaging

    NASA Astrophysics Data System (ADS)

    Karpov, Dmitry; dos Santos Rolo, Tomy; Rich, Hannah; Kryuchkov, Yuriy; Kiefer, Boris; Fohtung, E.

    2016-10-01

    Directional dependence of the index of refraction contains a wealth of information about anisotropic optical properties in semiconducting and insulating materials. Here we present a novel high-resolution lens-less technique that uses birefringence as a contrast mechanism to map the index of refraction and dielectric permittivity in optically anisotropic materials. We applied this approach successfully to a liquid crystal polymer film using polarized light from helium neon laser. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of emergent brilliant X-ray sources. Applications of this novel imaging technique are in disruptive technologies, including novel electronic devices, in which both charge and spin carry information as in multiferroic materials and photonic materials such as light modulators and optical storage.

  11. Multilayer diffraction grating

    SciTech Connect

    Barbee, T.W., Jr.

    1988-10-18

    This invention is for a reflection diffraction grating that functions at x-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  12. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, G.E.

    1996-08-29

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

  13. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, Gary E.

    1996-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  14. Diffraction and Unitarity

    NASA Astrophysics Data System (ADS)

    Dremin, I. M.

    I begin with a tribute to V.N. Gribov and then come to a particular problem which would be of interest for him. His first paper on reggeology was devoted to elastic scatterings of hadrons. Here, using the unitarity relation in combination with experimental data about the elastic scattering in the diffraction cone, I show how the shape and the darkness of the interaction region of colliding protons change with the increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. The possible evolution with increasing energy of the shape from the dark core at the LHC to the fully transparent one at higher energies is discussed. It implies that the terminology of the black disk would be replaced by the black torus.

  15. Diffraction and unitarity

    NASA Astrophysics Data System (ADS)

    Dremin, I. M.

    2016-10-01

    I begin with a tribute to V.N. Gribov and then come to a particular problem which would be of interest for him. His first paper on reggeology was devoted to elastic scatterings of hadrons. Here, using the unitarity relation in combination with experimental data about the elastic scattering in the diffraction cone, I show how the shape and the darkness of the interaction region of colliding protons change with the increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. The possible evolution with increasing energy of the shape from the dark core at the LHC to the fully transparent one at higher energies is discussed. It implies that the terminology of the black disk would be replaced by the black torus.

  16. Dichroic coherent diffractive imaging

    PubMed Central

    Tripathi, Ashish; Mohanty, Jyoti; Dietze, Sebastian H.; Shpyrko, Oleg G.; Shipton, Erik; Fullerton, Eric E.; Kim, Sang Soo; McNulty, Ian

    2011-01-01

    Understanding electronic structure at the nanoscale is crucial to untangling fundamental physics puzzles such as phase separation and emergent behavior in complex magnetic oxides. Probes with the ability to see beyond surfaces on nanometer length and subpicosecond time scales can greatly enhance our understanding of these systems and will undoubtedly impact development of future information technologies. Polarized X-rays are an appealing choice of probe due to their penetrating power, elemental and magnetic specificity, and high spatial resolution. The resolution of traditional X-ray microscopes is limited by the nanometer precision required to fabricate X-ray optics. Here we present a novel approach to lensless imaging of an extended magnetic nanostructure, in which a scanned series of dichroic coherent diffraction patterns is recorded and numerically inverted to map its magnetic domain configuration. Unlike holographic methods, it does not require a reference wave or precision optics. In addition, it enables the imaging of samples with arbitrarily large spatial dimensions, at a spatial resolution limited solely by the coherent X-ray flux, wavelength, and stability of the sample with respect to the beam. It can readily be extended to nonmagnetic systems that exhibit circular or linear dichroism. We demonstrate this approach by imaging ferrimagnetic labyrinthine domains in a Gd/Fe multilayer with perpendicular anisotropy and follow the evolution of the domain structure through part of its magnetization hysteresis loop. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of the new generation of phenomenally brilliant X-ray sources. PMID:21825152

  17. Dichroic Coherent Diffractive Imaging

    NASA Astrophysics Data System (ADS)

    Tripathi, Ashish

    Understanding electronic structure at nanometer resolution is crucial to understanding physics such as phase separation and emergent behavior in correlated electron materials. Nondestructive probes which have the ability to see beyond surfaces on nanometer length and sub-picosecond time scales can greatly enhance our understanding of these systems and will impact development of future technologies, such as magnetic storage. Polarized x-rays are an appealing choice of probe due to their penetrating power, elemental and magnetic specificity, and high spatial resolution. The resolution of traditional x-ray microscopy is limited by the nanometer precision required to fabricate x-ray optics. In this thesis, a novel approach to lensless imaging of an extended magnetic nanostructure is presented. We demonstrate this approach by imaging ferrimagnetic "maze" domains in a Gd/Fe multilayer with perpendicular anisotropy. A series of dichroic coherent diffraction patterns, ptychographically recorded, are numerically inverted using non-convex and non-linear optimization theory, and we follow the magnetic domain configuration evolution through part of its magnetization hysteresis loop by applying an external magnetic field. Unlike holographic methods, it does not require a reference wave or precision optics, and so is a far simpler experiment. In addition, it enables the imaging of samples with arbitrarily large spatial dimensions, at a spatial resolution limited solely by the coherent x-ray flux and wavelength. It can readily be extended to other non-magnetic systems that exhibit circular or linear dichroism. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of the new generation of phenomenally brilliant x-ray sources.

  18. Dichroic coherent diffractive imaging.

    PubMed

    Tripathi, Ashish; Mohanty, Jyoti; Dietze, Sebastian H; Shpyrko, Oleg G; Shipton, Erik; Fullerton, Eric E; Kim, Sang Soo; McNulty, Ian

    2011-08-16

    Understanding electronic structure at the nanoscale is crucial to untangling fundamental physics puzzles such as phase separation and emergent behavior in complex magnetic oxides. Probes with the ability to see beyond surfaces on nanometer length and subpicosecond time scales can greatly enhance our understanding of these systems and will undoubtedly impact development of future information technologies. Polarized X-rays are an appealing choice of probe due to their penetrating power, elemental and magnetic specificity, and high spatial resolution. The resolution of traditional X-ray microscopes is limited by the nanometer precision required to fabricate X-ray optics. Here we present a novel approach to lensless imaging of an extended magnetic nanostructure, in which a scanned series of dichroic coherent diffraction patterns is recorded and numerically inverted to map its magnetic domain configuration. Unlike holographic methods, it does not require a reference wave or precision optics. In addition, it enables the imaging of samples with arbitrarily large spatial dimensions, at a spatial resolution limited solely by the coherent X-ray flux, wavelength, and stability of the sample with respect to the beam. It can readily be extended to nonmagnetic systems that exhibit circular or linear dichroism. We demonstrate this approach by imaging ferrimagnetic labyrinthine domains in a Gd/Fe multilayer with perpendicular anisotropy and follow the evolution of the domain structure through part of its magnetization hysteresis loop. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of the new generation of phenomenally brilliant X-ray sources.

  19. Super-Hard Superconductivity

    NASA Astrophysics Data System (ADS)

    Adams, Philip; Prozorov, Ruslan

    2005-03-01

    We present the magnetic response of Type-II superconductivity in the extreme pinning limit, where screening currents within an order of magnitude of the Ginzburg-Landau depairing critical current density develop upon the application of a magnetic field. We show that this ``super-hard'' limit is well approximated in highly disordered, cold drawn, Nb wire whose magnetization response is characterized by a cascade of Meissner-like phases, each terminated by a catastrophic collapse of the magnetization. Direct magneto-optic measurements of the flux penetration depth in the virgin magnetization branch are in excellent agreement with the exponential model in which Jc(B)=Jco(-B/Bo), where Jco˜5x10^6 A/cm^2 for Nb. The implications for the fundamental limiting hardness of a superconductor will be discussed.

  20. Inclusive and Exclusive Compton Processes in Quantum Chromodynamics

    SciTech Connect

    Psaker, Ales

    2005-12-01

    In our work, we describe two types of Compton processes. As an example of an inclusive process, we consider the high-energy photoproduction of massive muon pairs off the nucleon. We analyze the process in the framework of the QCD parton model, in which the usual parton distributions emerge as a tool to describe the nucleon in terms of quark and gluonic degrees of freedom. To study its exclusive version, a new class of phenomenological functions is required, namely, generalized parton distributions. They can be considered as a generalization of the usual parton distributions measured in deeply inelastic lepton-nucleon scattering. Generalized parton distributions (GPDs) may be observed in hard exclusive reactions such as deeply virtual Compton scattering. We develop an extension of this particular process into the weak interaction sector. We also investigate a possible application of the GPD formalism to wide-angle real Compton scattering.

  1. Meson Form Factors and Deep Exclusive Meson Production Experiments

    NASA Astrophysics Data System (ADS)

    Horn, Tanja

    2017-03-01

    Pion and kaon electroproduction data play a unique role in Nature and our understanding of them is essential for explaining hadron structure. Precision longitudinaltransverse separated pion and kaon cross sections are of particular interest. They allow for the extraction of meson form factors and validation of understanding of hard exclusive and semi-inclusive reactions (π+, K+, π0, γ) towards 3D hadron imaging and potential future flavor decomposition. We review recent data and present prospects for deep exclusive pion and kaon electroproduction at the 12 GeV Jefferson Lab including the prospects to use projected charged- and neutral pion data to further determine the spin, charge-parity and flavor of GPDs, including the helicity-flip GPDs.

  2. Periodically kicked hard oscillators.

    PubMed

    Cecchi, G. A.; Gonzalez, D. L.; Magnasco, M. O.; Mindlin, G. B.; Piro, O.; Santillan, A. J.

    1993-01-01

    A model of a hard oscillator with analytic solution is presented. Its behavior under periodic kicking, for which a closed form stroboscopic map can be obtained, is studied. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two regions correspond to very small or very large amplitude of the external force and match the corresponding regions in soft oscillators (invertible degree one and degree zero circle maps, respectively). There are two new regions for intermediate amplitude of the forcing. Region 3 corresponds to moderate high forcing, and is intrinsic to hard oscillators; it is characterized by discontinuous circle maps with a flat segment. Region 2 (low moderate forcing) has a certain resemblance to a similar region in soft oscillators (noninvertible degree one circle maps); however, the limit set of the dynamics in this region is not a circle, but a branched manifold, obtained as the tangent union of a circle and an interval; the topological structure of this object is generated by the finite size of the repelling set, and is therefore also intrinsic to hard oscillators.

  3. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K; Bhattacharya, R; Blau, Peter Julian; Clemons, Art; Eberle, Cliff; Evans, H B; Janke, Christopher James; Jolly, Brian C; Lee, E H; Leonard, Keith J; Trejo, Rosa M; Rivard, John D

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  4. Diffraction-based optical correlator

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

    2005-01-01

    Method and system for wavelength-based processing of a light beam. A light beam, produced at a chemical or physical reaction site and having at least first and second wavelengths, ?1 and ?2, is received and diffracted at a first diffraction grating to provide first and second diffracted beams, which are received and analyzed in terms of wavelength and/or time at two spaced apart light detectors. In a second embodiment, light from first and second sources is diffracted and compared in terms of wavelength and/or time to determine if the two beams arise from the same source. In a third embodiment, a light beam is split and diffracted and passed through first and second environments to study differential effects. In a fourth embodiment, diffracted light beam components, having first and second wavelengths, are received sequentially at a reaction site to determine whether a specified reaction is promoted, based on order of receipt of the beams. In a fifth embodiment, a cylindrically shaped diffraction grating (uniform or chirped) is rotated and translated to provide a sequence of diffracted beams with different wavelengths. In a sixth embodiment, incident light, representing one or more symbols, is successively diffracted from first and second diffraction gratings and is received at different light detectors, depending upon the wavelengths present in the incident light.

  5. Exchange-spring mechanism of soft and hard ferrite nanocomposites

    SciTech Connect

    Manjura Hoque, S.; Srivastava, C.; Kumar, V.; Venkatesh, N.; Das, H.N.; Saha, D.K.; Chattopadhyay, K.

    2013-08-01

    Graphical abstract: - Highlights: • Exchange-spring behaviour of soft and hard ferrites was studied. • XRD patterns indicated soft and hard ferrites as fcc and hcp structure. • Hysteresis loops indicate wide difference in coercivity of soft and hard phases. • Nanocomposites produced convex hysteresis loop characteristic of single-phase. - Abstract: The paper reports exchange-spring soft and hard ferrite nanocomposites synthesized by chemical co-precipitation with or without the application of ultrasonic vibration. The composites contained BaFe{sub 12}O{sub 19} as the hard phase and CoFe{sub 2}O{sub 4}/MgFe{sub 2}O{sub 4} as the soft phase. X-ray diffraction patterns of the samples in the optimum calcined condition indicated the presence of soft ferrites as face-centred cubic (fcc) and hard ferrites as hexagonal close packed (hcp) structure respectively. Temperature dependence of magnetization in the range of 20–700 °C demonstrated distinct presence of soft and hard ferrites as magnetic phases which are characterized by wide difference in magnetic anisotropy and coercivity. Exchange-spring mechanism led these nanocomposite systems to exchange-coupled, which ultimately produced convex hysteresis loops characteristic of a single-phase permanent magnet. Fairly high value of coercivity and maximum energy product were observed for the samples in the optimum calcined conditions with a maximum applied field of 1600 kA/m (2 T)

  6. Staking Tool for Hard Metals

    NASA Technical Reports Server (NTRS)

    Stein, J. A.

    1982-01-01

    Simple tool stakes hard-steel parts--that is, forces one part into recess on another, deforming receiving part so that it restrains inserted one. Tool allows small machine shops to stake hard steel without massive presses. Can be used, for example, to insert ball and spring into hard steel snap-tool body such as that used to turn socket wrenches. Use is not limited to hard steel; can be used as well to assemble parts made of softer materials.

  7. Diffractive heavy quark production in AA collisions at the LHC at NLO

    SciTech Connect

    Machado, M. M.; Ducati, M. B. Gay; Machado, M. V. T.

    2011-07-15

    The single and double diffractive cross sections for heavy quarks production are evaluated at NLO accuracy for hadronic and heavy ion collisions at the LHC. Diffractive charm and bottom production is the main subject of this work, providing predictions for CaCa, PbPb and pPb collisions. The hard diffraction formalism is considered using the Ingelman-Schlein model where a recent parametrization for the Pomeron structure function (DPDF) is applied. Absorptive corrections are taken into account as well. The diffractive ratios are estimated and theoretical uncertainties are discussed. Comparison with competing production channels is also presented.

  8. Quantifying recrystallization by electron backscatter diffraction.

    PubMed

    Jazaeri, H; Humphreys, F J

    2004-03-01

    The use of high-resolution electron backscatter diffraction in the scanning electron microscope to quantify the volume fraction of recrystallization and the recrystallization kinetics is discussed. Monitoring the changes of high-angle grain boundary (HAGB) content during annealing is shown to be a reliable method of determining the volume fraction of recrystallization during discontinuous recrystallization, where a large increase in the percentage of high-angle boundaries occurs during annealing. The results are shown to be consistent with the standard methods of studying recrystallization, such as quantitative metallography and hardness testing. Application of the method to a highly deformed material has shown that it can be used to identify the transition from discontinuous to continuous recrystallization during which there is no significant change in the percentage of HAGB during annealing.

  9. Rapidity gaps in hard processes at D0

    SciTech Connect

    Perkins, J.

    1996-09-01

    Latest results on jet production with rapidity gaps at the Fermilab Tevatron Collider are presented. Jet production via color-singlet exchange at high momenta transfer is observed as a class of events with low particle multiplicity (or rapidity gaps) between the two highest transverse energy jets. The particle multiplicity in various regions, and the dependencies on jet pseudorapidity separation and jet transverse energy are studied for these events. Results from two classes of dijet events with one or two forward rapidity gaps are also presented. The topology of these events is consistent with expectations for hard single diffraction and hard double pomeron exchange processes, respectively.

  10. Diffraction at HFIR

    SciTech Connect

    Chakoumakos, Bryan C; Fernandez-Baca, Jaime A; Garlea, Vasile O; Hubbard, Camden R; Wang, Xun-Li

    2008-01-01

    Of the planned suite of powder and single-crystal diffractometers for the HFIR, only two are currently operating, the Neutron Residual Stress Mapping Facility (NRSF2) diffractometer, and the Wide Angle Neutron Diffractometer (WAND). The NSRF2 was recently upgraded and is available to external users via the High Temperature Materials Laboratory (HTML) User Program for studies of stress, texture and phase mapping. The WAND is a flat-cone geometry diffractometer equipped with a curve 1-D PSD, suitable for high intensity powder diffraction (e.g., kinetics, high pressure) and diffuse scattering studies of single-crystals. A rebuild of the old HFIR powder diffractometer, originally located at HB-4 station is now underway, and is expected to begin commissioning by summer 2008. This instrument has a Debye-Scherrer geometry, with a detector bank consisting of 44 3He tubes each with 6' Soller collimators. A four-circle single-crystal diffractometer is located at the HB-3A station, and is slowly being brought back to life after the long hiatus connected to the reactor upgrade. A Letter of Intent to build a quasi-Laue diffractometer, called IMAGINE, in the HFIR Cold Guide Hall has been presented to and endorsed by the Neutron Scattering Science Advisory Committee.

  11. Diffractive parameric colors.

    PubMed

    Orava, Joni; Heikkila, Noora; Jaaskelainen, Timo; Parkkinen, Jussi

    2008-12-01

    A method of producing inkless parameric color pairs is studied. In this method, colors are formed additively using diffraction gratings with differing grating periods as primary colors. Gratings with different grating periods reflect different spectral radiance peaks of a fluorescent lamp to the desired viewing angle, according to the grating equation. Four spectral peaks of a 4000 K fluorescent lamp--red, green, cyan, and blue-are used as the primary colors. The colors are mixed additively by fixing the relative areas of different grating periods inside a pixel. With four primary colors it is possible to mix certain colors with different triplets of primary colors. Thus, it is theoretically possible to produce metameric colors. In this study, three parameric color pairs are fabricated using electron beam lithography, electroplating, and hot embossing. The radiance spectra of the color pairs are measured by spectroradiometer from hot-embossed plastic samples. The CIELAB DeltaE(ab) and CIEDE2000 color differences between radiance spectra of the color pairs are calculated. The CIEDE2000 color differences of color pairs are between 2.6 and 7.2 units in reference viewing conditions. The effects of viewing angle and different light sources are also evaluated. It is found that both the viewing angle and the light source have very strong influences on the color differences of the color pairs.

  12. Intrapersonal and interpersonal processes of social exclusion

    PubMed Central

    Kawamoto, Taishi; Ura, Mitsuhiro; Nittono, Hiroshi

    2015-01-01

    People have a fundamental need to belong with others. Social exclusion impairs this need and has various effects on cognition, affect, and the behavior of excluded individuals. We have previously reported that activity in the dorsal anterior cingulate cortex (dACC) and right ventrolateral prefrontal cortex (rVLPFC) could be a neurocognitive index of social exclusion (Kawamoto et al., 2012). In this article, we provide an integrative framework for understanding occurrences during and after social exclusion, by reviewing neuroimaging, electrophysiological, and behavioral studies of dACC and rVLPFC, within the framework of intrapersonal and interpersonal processes of social exclusion. As a result, we have indicated directions for future studies to further clarify the phenomenon of social exclusion from the following perspectives: (1) constructional elements of social exclusion, (2) detection sensitivity and interpretation bias in social exclusion, (3) development of new methods to assess the reactivity to social exclusion, and (4) sources of social exclusion. PMID:25798081

  13. Nanofluidic Size-Exclusion Chromatograph

    NASA Technical Reports Server (NTRS)

    Feldman, Sabrina; Svehla, Danielle; Grunthaner, Frank; Feldman, Jason; Shakkottai, P.

    2004-01-01

    Efforts are under way to develop a nanofluidic size-exclusion chromatograph (SEC), which would be a compact, robust, lightweight instrument for separating molecules of interest according to their sizes and measuring their relative abundances in small samples. About as large as a deck of playing cards, the nanofluidic SEC would serve, in effect, as a laboratory on a chip that would perform the functions of a much larger, conventional, bench-top SEC and ancillary equipment, while consuming much less power and much smaller quantities of reagent and sample materials. Its compactness and low power demand would render it attractive for field applications in which, typically, it would be used to identify and quantitate a broad range of polar and nonpolar organic compounds in soil, ice, and water samples. Size-exclusion chromatography is a special case of high-performance liquid chromatography. In a conventional SEC, a sample plug is driven by pressure along a column packed with silica or polymer beads that contain uniform nanopores. The interstices between, and the pores in, the beads collectively constitute a size-exclusion network. Molecules follow different paths through the size-exclusion network, such that characteristic elution times can be related to sizes of molecules: basically, smaller molecules reach the downstream end of the column after the larger ones do because the smaller ones enter minor pores and stay there for a while, whereas the larger ones do not enter the pores. The volume accessible to molecules gradually diminishes as their size increases. All molecules bigger than a pore size elute together. For most substances, the elution times and sizes of molecules can be correlated directly with molecular weights. Hence, by measuring the flux of molecules arriving at the downstream end as a function of time, one can obtain a liquid mass spectrum for the molecules present in a sample over a broad range of molecular weights.

  14. Exclusive breastfeeding: measurement and indicators.

    PubMed

    Greiner, Ted

    2014-01-01

    Accurate measurement of the duration of exclusive breastfeeding is complicated by factors related to definitions, timing, duration of recall, methods of analysis, and sample biases. Clearly prospective methods are likely to be more accurate but are too expensive to use in most large-scale surveys. Internationally, most surveys use a point-in-time or current status measurement (usually 24-hour recall) and report their findings using an indicator established by the World Health Organisation (WHO) in 1991 that involves combining all babies less than six months old in order to obtain a large enough sample size to result in stable proportions that can be compared over time. However, this indicator is complex to understand and explain and is widely misunderstood, even within the breastfeeding community. It is commonly cited in ways that greatly exaggerate how common exclusive breastfeeding actually is. A life-long or since birth indicator, introduced in 2000, counts infants as no longer exclusively breastfed as soon as anything else is fed to them. This is appropriate to do if for example data are being used to link infant feeding patterns with vertical transmission of HIV or later patterns of infant allergy. However, this indicator underestimates the total extent of exclusive breastfeeding, since some women interrupt but then resume it after a period of supplementation (which could for example only be a small amount of water given a single time). Exactly which indicator is best to use depends on the purpose for which the data are being used. However, for surveys, the best approach, rarely used, would be to report indicators based on both point-in-time and life-long data.

  15. Study of optical Laue diffraction

    NASA Astrophysics Data System (ADS)

    Chakravarthy, Giridhar; Allam, Srinivasa Rao; Satyanarayana, S. V. M.; Sharan, Alok

    2014-10-01

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  16. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, Antonio J.; Butler, Michael A.; Sinclair, Michael B.; Senturia, Stephen D.

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  17. Study of optical Laue diffraction

    SciTech Connect

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  18. Hard metal composition

    DOEpatents

    Sheinberg, Haskell

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  19. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  20. Revisiting the definition of local hardness and hardness kernel.

    PubMed

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  1. Hard Metal Disease

    PubMed Central

    Bech, A. O.; Kipling, M. D.; Heather, J. C.

    1962-01-01

    In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

  2. Tolerance analysis on diffraction efficiency and polychromatic integral diffraction efficiency for harmonic diffractive optics

    NASA Astrophysics Data System (ADS)

    Shan, Mao

    2016-10-01

    In this dissertation, the mathematical model of effect of manufacturing errors including microstructure relative height error and relative width error on diffraction efficiency for the harmonic diffractive optical elements (HDEs) is set up. According to the expression of the phase delay and diffraction efficiency of the HDEs, the expression of diffraction efficiency of refraction and diffractive optical element with the microstructure height and periodic width errors in fabrication process is presented in this paper. Furthermore, the effect of manufacturing errors on diffraction efficiency for the harmonic diffractive optical elements is studied, and diffraction efficiency change is analyzed as the relative microstructure height-error in the same and in the opposite sign as well as relative width-error in the same and in the opposite sign. Example including infrared wavelength with materials GE has been discussed in this paper. Two kinds of manufacturing errors applied in 3.7 4.3um middle infrared and 8.7-11.5um far infrared optical system which results in diffraction efficiency and PIDE of HDEs are studied. The analysis results can be used for manufacturing error control in micro-structure height and periodic width. Results can be used for HDEs processing.

  3. 76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing..., Synthesis of and Methods of Use Thereof AGENCY: Department of the Army, DoD. ACTION: Notice. SUMMARY... represented by the Secretary of the Army, has rights to this invention. ADDRESSES: Commander, U.S....

  4. 78 FR 6814 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-31

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing... Epitopes AGENCY: Department of the Army, DoD. ACTION: Notice. SUMMARY: Announcement is made of the... September 22, 2006. The United States Government as represented by the Secretary of the Army has rights...

  5. 76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing... Agents, Synthesis of and Methods of Use Thereof AGENCY: Department of the Army, DoD. ACTION: Notice... United States Government, as represented by the Secretary of the Army, has rights to this...

  6. 77 FR 2278 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Army Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an Invention Concerning a Method and Device for Detection of Bioavailable Drug Concentration in a...

  7. Inelastic diffraction at the LHC

    NASA Astrophysics Data System (ADS)

    Troshin, S. M.; Tyurin, N. E.

    2017-03-01

    The relativistic scattering was one of the scientific fields where Academician V.G. Kadyshevsky has made an important and highly cited contribution [1]. In this paper we discuss the high-energy dependencies of diffractive and non-diffractive inelastic cross-sections in view of the recent LHC data which reveal a presence of the reflective scattering mode.

  8. Computer Simulation of Diffraction Patterns.

    ERIC Educational Resources Information Center

    Dodd, N. A.

    1983-01-01

    Describes an Apple computer program (listing available from author) which simulates Fraunhofer and Fresnel diffraction using vector addition techniques (vector chaining) and allows user to experiment with different shaped multiple apertures. Graphics output include vector resultants, phase difference, diffraction patterns, and the Cornu spiral…

  9. Ptychographic Fresnel coherent diffractive imaging

    SciTech Connect

    Vine, D. J.; Williams, G. J.; Nugent, K. A.; Abbey, B.; Pfeifer, M. A.; Clark, J. N.; Peele, A. G.; Jonge, M. D. de; McNulty, I.

    2009-12-15

    This paper reports improved reconstruction of complex wave fields from extended objects. The combination of ptychography with Fresnel diffractive imaging results in better reconstructions with fewer iterations required to convergence than either method considered separately. The method is applied to retrieve the projected thickness of a gold microstructure and comparative results using ptychography and Fresnel diffractive imaging are presented.

  10. A perturbative approach to central exclusive production

    NASA Astrophysics Data System (ADS)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.

    2015-02-01

    We review some selected results within the Durham model of central exclusive production. We present a detailed discussion of this theoretical approach for modeling exclusive processes and we briefly review some of its phenomenological applications.

  11. Lamb wave diffraction tomography

    NASA Astrophysics Data System (ADS)

    Malyarenko, Eugene Valentinovich

    , fails. Diffraction tomography is a way to incorporate scattering effects into tomographic algorithms in order to improve image quality and resolution. This work describes the iterative reconstruction procedure developed for the Lamb Wave tomography and allowing for ray bending correction for imaging of moderately scattering objects.

  12. Exclusion Bounds for Extended Anyons

    NASA Astrophysics Data System (ADS)

    Larson, Simon; Lundholm, Douglas

    2017-08-01

    We introduce a rigorous approach to the many-body spectral theory of extended anyons, that is quantum particles confined to two dimensions that interact via attached magnetic fluxes of finite extent. Our main results are many-body magnetic Hardy inequalities and local exclusion principles for these particles, leading to estimates for the ground-state energy of the anyon gas over the full range of the parameters. This brings out further non-trivial aspects in the dependence on the anyonic statistics parameter, and also gives improvements in the ideal (non-extended) case.

  13. Approximating spatially exclusive invasion processes.

    PubMed

    Ross, Joshua V; Binder, Benjamin J

    2014-05-01

    A number of biological processes, such as invasive plant species and cell migration, are composed of two key mechanisms: motility and reproduction. Due to the spatially exclusive interacting behavior of these processes a cellular automata (CA) model is specified to simulate a one-dimensional invasion process. Three (independence, Poisson, and 2D-Markov chain) approximations are considered that attempt to capture the average behavior of the CA. We show that our 2D-Markov chain approximation accurately predicts the state of the CA for a wide range of motility and reproduction rates.

  14. Diffractive Z boson pair production at the LHC in the large extra dimensions scenario

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Sauter, W. K.; Thiel, M.

    2014-04-01

    In this paper we study the diffractive Z boson pair production mediated by the Kaluza-Klein graviton in the large extra dimensions scenario at the CERN Large Hadron Collider energies. Considering the Durham model, we estimate the total cross section for the central inclusive and exclusive diffractive production of a Z boson pair in pp/pPb/PbPb collisions. Our results indicate that the experimental analysis of the central inclusive production in pp collisions is feasible at the CERN LHC.

  15. 40 CFR 1508.4 - Categorical exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Categorical exclusion. 1508.4 Section 1508.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY TERMINOLOGY AND INDEX § 1508.4 Categorical exclusion. Categorical exclusion means a category of actions which do not individually...

  16. 5 CFR 582.103 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Exclusions. 582.103 Section 582.103 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS COMMERCIAL GARNISHMENT OF FEDERAL EMPLOYEES' PAY Purpose, Definitions, and Exclusions § 582.103 Exclusions. In determining the...

  17. Diffractive di-jet production at the LHC with a Reggeon contribution

    NASA Astrophysics Data System (ADS)

    Marquet, C.; Martins, D. E.; Pereira, A. V.; Rangel, M.; Royon, C.

    2017-03-01

    We study hard diffractive scattering in hadron-hadron collisions including, on top of the standard Pomeron-initiated processes, contributions due to the exchange of Reggeons. Using a simple model to describe the parton content of the Reggeon, we compute di-jet production in single diffractive and central diffractive events. We show that Reggeon contributions can be sizable at the LHC, and even sometimes dominant, and we identify kinematic windows in which they could be experimentally studied. We argue that suitable measurements must be performed in order to properly constrain the model, and be able to correctly account for Reggeon exchanges in the analysis of the many hard diffractive observables to be measured at the LHC.

  18. Optical diffraction properties of multimicrogratings

    SciTech Connect

    Rothenbach, Christian A.; Kravchenko, Ivan I.; Gupta, Mool C.

    2015-02-27

    This paper shows the results of optical diffraction properties of multimicrograting structures fabricated by e-beam lithography. Multimicrograting consist of arrays of hexagonally shaped cells containing periodic one-dimensional (1D) grating lines in different orientations and arrayed to form large area patterns. We analyzed the optical diffraction properties of multimicrogratings by studying the individual effects of the several periodic elements of multimicrogratings. The observed optical diffraction pattern is shown to be the combined effect of the periodic and non-periodic elements that define the multimicrogratings and the interaction between different elements. We measured the total transverse electric (TE) diffraction efficiency of multimicrogratings and found it to be 32.1%, which is closely related to the diffraction efficiency of 1D periodic grating lines of the same characteristics, measured to be 33.7%. Beam profiles of the optical diffraction patterns from multimicrogratings are captured with a CCD sensor technique. Interference fringes were observed under certain conditions formed by multimicrograting beams interfering with each other. Finally, these diffraction structures may find applications in sensing, nanometrology, and optical interconnects.

  19. Optical diffraction properties of multimicrogratings

    DOE PAGES

    Rothenbach, Christian A.; Kravchenko, Ivan I.; Gupta, Mool C.

    2015-02-27

    This paper shows the results of optical diffraction properties of multimicrograting structures fabricated by e-beam lithography. Multimicrograting consist of arrays of hexagonally shaped cells containing periodic one-dimensional (1D) grating lines in different orientations and arrayed to form large area patterns. We analyzed the optical diffraction properties of multimicrogratings by studying the individual effects of the several periodic elements of multimicrogratings. The observed optical diffraction pattern is shown to be the combined effect of the periodic and non-periodic elements that define the multimicrogratings and the interaction between different elements. We measured the total transverse electric (TE) diffraction efficiency of multimicrogratings andmore » found it to be 32.1%, which is closely related to the diffraction efficiency of 1D periodic grating lines of the same characteristics, measured to be 33.7%. Beam profiles of the optical diffraction patterns from multimicrogratings are captured with a CCD sensor technique. Interference fringes were observed under certain conditions formed by multimicrograting beams interfering with each other. Finally, these diffraction structures may find applications in sensing, nanometrology, and optical interconnects.« less

  20. Social exclusion decreases prosocial behavior.

    PubMed

    Twenge, Jean M; Baumeister, Roy F; DeWall, C Nathan; Ciarocco, Natalie J; Bartels, J Michael

    2007-01-01

    In 7 experiments, the authors manipulated social exclusion by telling people that they would end up alone later in life or that other participants had rejected them. Social exclusion caused a substantial reduction in prosocial behavior. Socially excluded people donated less money to a student fund, were unwilling to volunteer for further lab experiments, were less helpful after a mishap, and cooperated less in a mixed-motive game with another student. The results did not vary by cost to the self or by recipient of the help, and results remained significant when the experimenter was unaware of condition. The effect was mediated by feelings of empathy for another person but was not mediated by mood, state self-esteem, belongingness, trust, control, or self-awareness. The implication is that rejection temporarily interferes with emotional responses, thereby impairing the capacity for empathic understanding of others, and as a result, any inclination to help or cooperate with them is undermined. 2007 APA, all rights reserved

  1. Choreography of Ig allelic exclusion.

    PubMed

    Cedar, Howard; Bergman, Yehudit

    2008-06-01

    Allelic exclusion guarantees that each B or T cell only produces a single antigen receptor, and in this way contributes to immune diversity. This process is actually initiated in the early embryo when the immune receptor loci become asynchronously replicating in a stochastic manner with one early and one late allele in each cell. This distinct differential replication timing feature then serves an instructive mark that directs a series of allele-specific epigenetic events in the immune system, including programmed histone modification, nuclear localization and DNA demethylation that ultimately bring about preferred rearrangement on a single allele, and this decision is temporally stabilized by feedback mechanisms that inhibit recombination on the second allele. In principle, these same molecular components are also used for controlling monoallelic expression at other genomic loci, such as those carrying interleukins and olfactory receptor genes that require the choice of one gene out of a large array. Thus, allelic exclusion appears to represent a general epigenetic phenomenon that is modeled on the same basis as X chromosome inactivation.

  2. Exclusion Process with Slow Boundary

    NASA Astrophysics Data System (ADS)

    Baldasso, Rangel; Menezes, Otávio; Neumann, Adriana; Souza, Rafael R.

    2017-06-01

    We study the hydrodynamic and the hydrostatic behavior of the simple symmetric exclusion process with slow boundary. The term slow boundary means that particles can be born or die at the boundary sites, at a rate proportional to N^{-θ }, where θ > 0 and N is the scaling parameter. In the bulk, the particles exchange rate is equal to 1. In the hydrostatic scenario, we obtain three different linear profiles, depending on the value of the parameter θ ; in the hydrodynamic scenario, we obtain that the time evolution of the spatial density of particles, in the diffusive scaling, is given by the weak solution of the heat equation, with boundary conditions that depend on θ . If θ \\in (0,1), we get Dirichlet boundary conditions, (which is the same behavior if θ =0, see Farfán in Hydrostatics, statical and dynamical large deviations of boundary driven gradient symmetric exclusion processes, 2008); if θ =1, we get Robin boundary conditions; and, if θ \\in (1,∞), we get Neumann boundary conditions.

  3. Janka hardness using nonstandard specimens

    Treesearch

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  4. Tuning hardness in calcite by incorporation of amino acids

    NASA Astrophysics Data System (ADS)

    Kim, Yi-Yeoun; Carloni, Joseph D.; Demarchi, Beatrice; Sparks, David; Reid, David G.; Kunitake, Miki E.; Tang, Chiu C.; Duer, Melinda J.; Freeman, Colin L.; Pokroy, Boaz; Penkman, Kirsty; Harding, John H.; Estroff, Lara A.; Baker, Shefford P.; Meldrum, Fiona C.

    2016-08-01

    Structural biominerals are inorganic/organic composites that exhibit remarkable mechanical properties. However, the structure-property relationships of even the simplest building unit--mineral single crystals containing embedded macromolecules--remain poorly understood. Here, by means of a model biomineral made from calcite single crystals containing glycine (0-7 mol%) or aspartic acid (0-4 mol%), we elucidate the origin of the superior hardness of biogenic calcite. We analysed lattice distortions in these model crystals by using X-ray diffraction and molecular dynamics simulations, and by means of solid-state nuclear magnetic resonance show that the amino acids are incorporated as individual molecules. We also demonstrate that nanoindentation hardness increased with amino acid content, reaching values equivalent to their biogenic counterparts. A dislocation pinning model reveals that the enhanced hardness is determined by the force required to cut covalent bonds in the molecules.

  5. Global analysis of exclusive kaon and pion electroproduction

    NASA Astrophysics Data System (ADS)

    Horn, T.

    2012-01-01

    The p(e,e'π+)n and p(e,e',K+)Λ (Σ0) reactions are important tools in the study of hadron structure. In particular, the flavor degree of freedom introduced with the addition of the strange quark helps us understand the reaction mechanism underlying strangeness production, and the transition from hadronic to partonic degrees of freedom in exclusive processes. In this study, we examine the world's data on exclusive p(e,e'π+)n and p(e,e'K+)Λ cross sections. The data were combined into a superset with one global uncertainty, and examined for -t dependence of the longitudinal and transverse components of the cross section as function of Q2 and the longitudinal momentum fraction, xB. The data suggest that the importance of t-channel meson exchange decreases at higher values of xB. The Q2 dependence of the longitudinal to transverse cross section ratio was compared with the Q2-scaling expectation for hard exclusive processes.

  6. Arbitrary shape surface Fresnel diffraction.

    PubMed

    Shimobaba, Tomoyoshi; Masuda, Nobuyuki; Ito, Tomoyoshi

    2012-04-09

    Fresnel diffraction calculation on an arbitrary shape surface is proposed. This method is capable of calculating Fresnel diffraction from a source surface with an arbitrary shape to a planar destination surface. Although such calculation can be readily calculated by the direct integral of a diffraction calculation, the calculation cost is proportional to O(N²) in one dimensional or O(N⁴) in two dimensional cases, where N is the number of sampling points. However, the calculation cost of the proposed method is O(N log N) in one dimensional or O(N² log N) in two dimensional cases using non-uniform fast Fourier transform.

  7. Diffractive optics in adverse environments

    NASA Technical Reports Server (NTRS)

    Behrmann, Gregory P.

    1993-01-01

    An investigation at the Army Research Laboratory is in progress to characterize DOE performance in mil-spec environments. One of the most significant environmental influences is temperature. An analysis of a diffractive lens is presented in which optical performance is described as a function of temperature. In particular, we review the thermal dependence of focal length and diffraction efficiency. It is shown that the change in these parameters is independent of lens shape and relates only to material properties. Thermalized hybrid refractive/diffractive designs are discussed.

  8. Diffraction dissociation at the LHC

    SciTech Connect

    Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  9. Phase retrieval in x-ray coherent Fresnel projection-geometry diffraction

    SciTech Connect

    De Caro, Liberato; Giannini, Cinzia; Cedola, Alessia; Pelliccia, Daniele; Lagomarsino, Stefano; Jark, Werner

    2007-01-22

    Coherent x-ray diffraction experiments were performed in Fresnel regime, within a line-projection geometry. A planar x-ray waveguide was used to focus coherent cylindrical waves onto a 7.2 {mu}m Kevlar fiber, which acts as a phase object for hard x rays. The phase was retrieved, by using a Fourier-based iterative phasing algorithm, consistent with measured diffraction data and known constraints in real space, with a submicrometer spatial resolution.

  10. Beam shaping in flow cytometry with diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Qu, Weidong; Li, Derong; Jian, Peng

    2016-10-01

    Focusing elements are usually employed in the flow cytometry to focus the input laser beam into elliptically shaped Gaussian beam in order to increase power for excitation of fluorescence for high signal-to-noise ratio (SNR). While in order to ensure repeatable and reliable signal generation for accurate population discrimination - despite slight deviations of the cell from the flow centre, the shaped beam should be a cubic diffraction region with uniform power intensity across the cell flow stream. However, it is hard for beam shaping with refractive optical elements. In this paper, we present a beam shaping system in flow cytometry with diffractive optical elements (DOEs) to shape the input laser beam to a cubic diffraction region with uniform power intensity. The phase distribution of the DOE is obtained by using the inverse Fresnel diffraction based layered holographic stereogram, and the cubic diffraction region with uniform power intensity within the cell flow channel is well reconstructed. Simulation results demonstrate the good performance of the new beam shaping system.

  11. Incorporating cultural beliefs in promoting exclusive breastfeeding

    PubMed Central

    Reinsma, Kathryn; Bolima, Nancy; Fonteh, Florence; Okwen, Patrick; Yota, Daniel; Montgomery, Susanne

    2015-01-01

    Introduction Since 2003, the World Health Organization has recommended exclusive breastfeeding for the first 6 months of life. In the Northwest region of Cameroon approximately 90% of women initiate breastfeeding, yet only 34% of these women exclusively breastfeed for the recommended six months. Aim To determine influences on women’s exclusive breastfeeding practices. Methods Semi-structured interviews were conducted with six women and six men followed by focus group discussions with three groups of women and three groups of men in the Kumbo West Health District, Northwest region, Cameroon. All participants were selected using theoretical sampling to assure triangulation. Results Three themes emerged that influence exclusive breastfeeding practices: woman’s readiness to exclusively breastfeed; cultural influences towards exclusive breastfeeding; and perceived constraints to exclusive breastfeeding. Conclusion These emergent themes were used to create a theoretical framework that is useful for developing a breastfeeding health education intervention in non-Western settings. PMID:26973717

  12. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  13. Femtosecond single-electron diffraction

    PubMed Central

    Lahme, S.; Kealhofer, C.; Krausz, F.; Baum, P.

    2014-01-01

    Ultrafast electron diffraction allows the tracking of atomic motion in real time, but space charge effects within dense electron packets are a problem for temporal resolution. Here, we report on time-resolved pump-probe diffraction using femtosecond single-electron pulses that are free from intra-pulse Coulomb interactions over the entire trajectory from the source to the detector. Sufficient average electron current is achieved at repetition rates of hundreds of kHz. Thermal load on the sample is avoided by minimizing the pump-probe area and by maximizing heat diffusion. Time-resolved diffraction from fibrous graphite polycrystals reveals coherent acoustic phonons in a nanometer-thick grain ensemble with a signal-to-noise level comparable to conventional multi-electron experiments. These results demonstrate the feasibility of pump-probe diffraction in the single-electron regime, where simulations indicate compressibility of the pulses down to few-femtosecond and attosecond duration. PMID:26798778

  14. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  15. Multiple annular linear diffractive axicons.

    PubMed

    Bialic, Emilie; de la Tocnaye, Jean-Louis de Bougrenet

    2011-04-01

    We propose a chromatic analysis of multiple annular linear diffractive axicons. Large aperture axicons are optical devices providing achromatic nondiffracting beams, with an extended depth of focus, when illuminated by a white light source, due to chromatic foci superimposition. Annular apertures introduce chromatic foci separation, and because chromatic aberrations result in focal segment axial shifts, polychromatic imaging properties are partially lost. We investigate here various design parameters that can be used to achieve color splitting, filtering, and combining using these properties. In order to improve the low-power efficiency of a single annular axicon, we suggest a spatial multiplexing of concentric annular axicons with different sizes and periods we call multiple annular aperture diffractive axicons (MALDAs). These are chosen to maintain focal depths while enabling color imaging with sufficient diffraction efficiency. Illustrations are given for binary phase diffractive axicons, considering technical aspects such as grating design wavelength and phase dependence due to the grating thickness.

  16. Fresnel diffraction by spherical obstacles

    NASA Technical Reports Server (NTRS)

    Hovenac, Edward A.

    1989-01-01

    Lommel functions were used to solve the Fresnel-Kirchhoff diffraction integral for the case of a spherical obstacle. Comparisons were made between Fresnel diffraction theory and Mie scattering theory. Fresnel theory is then compared to experimental data. Experiment and theory typically deviated from one another by less than 10 percent. A unique experimental setup using mercury spheres suspended in a viscous fluid significantly reduced optical noise. The major source of error was due to the Gaussian-shaped laser beam.

  17. Central exclusive production at RHIC

    SciTech Connect

    Adamczyk, Leszek; Guryn, Włodek; Turnau, Jacek

    2014-11-10

    The present status and future plans of the physics program of Central Exclusive Production (CEP) at RHIC are described. The measurements are based on the detection of the forward protons from the Double Pomeron Exchange (DPE) process in the Roman Pot system and of the recoil system of charged particles from the DPE process measured in the STAR experiment’s Time Projection Chamber (TPC). The data described here were taken using polarized proton-proton collisions at ps = 200 GeV. The preliminary spectra of two pion and four pion invariant mass reconstructed by STAR TPC in central region of pseudo-rapidity | | < 1, are presented. Near future plans to take data with the current system at center-of-mass energy ps = 200 GeV and plans to upgrade the forward proton tagging sys- tem are presented. Also a possible addition of the Roman Pots to the sPHENIX detector is discussed.

  18. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-08-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  19. Overview - Hard Rock Penetration

    SciTech Connect

    Dunn, James C.

    1992-03-24

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling Organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  20. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-01-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  1. Measuring the Hardness of Minerals

    ERIC Educational Resources Information Center

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  2. Diffractive and non-diffractive wounded nucleons and final states in pA collisions

    NASA Astrophysics Data System (ADS)

    Bierlich, Christian; Gustafson, Gösta; Lönnblad, Leif

    2016-10-01

    We review the state-of-the-art of Glauber-inspired models for estimating the distribution of the number of participating nucleons in p A and AA collisions. We argue that there is room for improvement in these model when it comes to the treatment of diffractive excitation processes, and present a new simple Glauber-like model where these processes are better taken into account. We also suggest a new way of using the number of participating, or wounded, nucleons to extrapolate event characteristics from pp collisions, and hence get an estimate of basic hadronic final-state properties in p A collisions, which may be used to extract possible nuclear effects. The new method is inspired by the Fritiof model, but based on the full, semi-hard multiparton interaction model of P ythia8.

  3. The AdS/QCD Correspondence and Exclusive Processes

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; Deur, Alexandre; /Jefferson Lab

    2010-08-25

    The AdS/CFT correspondence between theories in AdS space and conformal field theories in physical space-time provides an analytic, semi-classical, color-confining model for strongly-coupled QCD. The soft-wall AdS/QCD model modified by a positive-sign dilaton metric leads to a remarkable one-parameter description of nonperturbative hadron dynamics at zero quark mass, including a zero-mass pion and a Regge spectrum of linear trajectories with the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. One also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS}(q) and its {beta}-function which agrees with the effective coupling {alpha}{sub ga} extracted from the Bjorken sum rule. Light-front holography, which connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable {zeta}, allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties as well as decay constants, form factors, deeply virtual Compton scattering, exclusive heavy hadron decays and other exclusive scattering amplitudes. One thus obtains a relativistic description of hadrons in QCD at the amplitude level with dimensional counting for hard exclusive reactions at high momentum transfer. As specific examples we discuss the behavior of the pion and nucleon form factors in the space-like and time-like regions. We also review the phenomenology of exclusive processes including some anomalous empirical results.

  4. Diffraction efficiency analysis for multi-level diffractive optical elements

    SciTech Connect

    Erteza, I.A.

    1995-11-01

    Passive optical components can be broken down into two main groups: Refractive elements and diffractive elements. With recent advances in manufacturing technologies, diffractive optical elements are becoming increasingly more prevalent in optical systems. It is therefore important to be able to understand and model the behavior of these elements. In this report, we present a thorough analysis of a completely general diffractive optical element (DOE). The main goal of the analysis is to understand the diffraction efficiency and power distribution of the various modes affected by the DOE. This is critical to understanding cross talk and power issues when these elements are used in actual systems. As mentioned, the model is based on a completely general scenario for a DOE. This allows the user to specify the details to model a wide variety of diffractive elements. The analysis is implemented straightforwardly in Mathematica. This report includes the development of the analysis, the Mathematica implementation of the model and several examples using the Mathematical analysis tool. It is intended that this tool be a building block for more specialized analyses.

  5. Observation of hard processes in rapidity gap events in γp interactions at HERA

    NASA Astrophysics Data System (ADS)

    Ahmed, T.; Aid, S.; Andreev, V.; Andrieu, B.; Appuhn, R.-D.; Arpagaus, M.; Babaev, A.; Baehr, J.; Bán, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Barth, M.; Bassler, U.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bergstein, H.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besançon, M.; Beyer, R.; Biddulph, P.; Bizot, J. C.; Blobel, V.; Borras, K.; Botterweck, F.; Boudry, V.; Braemer, A.; Brasse, F.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Brune, C.; Buchholz, R.; Büngener, L.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A. B.; Clerbaux, B.; Colombo, M.; Contreras, J. G.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cussans, D. G.; Cvach, J.; Dagoret, S.; Dainton, J. B.; Danilov, M.; Dau, W. D.; Daum, K.; David, M.; Deffur, E.; Delcourt, B.; Del Buono, L.; De Roeck, A.; De Wolf, E. A.; Di Nezza, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Droutskoi, V.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Ehrlichmann, H.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Erdmann, W.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Fleischer, M.; Flieser, M.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Gabathuler, E.; Gabathuler, K.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gebauer, M.; Gellrich, A.; Genzel, H.; Gerhards, R.; Goerlach, U.; Goerlach, L.; Gogitidze, N.; Goldberg, M.; Goldner, D.; Gonzalez-Pineiro, B.; Goodall, A. M.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Grindhammer, G.; Gruber, A.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Hampel, M.; Hanlon, E. M.; Hapke, M.; Haynes, W. J.; Heatherington, J.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herma, R.; Herynek, I.; Hess, M. F.; Hildesheim, W.; Hill, P.; Hiller, K. H.; Hilton, C. D.; Hladký, J.; Hoeger, K. C.; Höppner, M.; Horisberger, R.; Huet, Ph.; Hufnagel, H.; Ibbotson, M.; Itterbeck, H.; Jabiol, M.-A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Janoth, J.; Jansen, T.; Jönsson, L.; Johannsen, K.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kant, D.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Kaufmann, H. H.; Kazarian, S.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Ko, W.; Köhler, T.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krämerkämper, T.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Krüner-Marquis, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kurča, T.; Kurzhöfer, J.; Kuznik, B.; Lacour, D.; Lamarche, F.; Lander, R.; Landon, M. P. J.; Lange, W.; Lanius, P.; Laporte, J.-F.; Lebedev, A.; Leverenz, C.; Levonian, S.; Ley, Ch.; Lindner, A.; Lindström, G.; Linsel, F.; Lipinski, J.; List, B.; Loch, P.; Lohmander, H.; Lopez, G. C.; Lubimov, V.; Lüke, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Maraček, R.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; Martyn, H.-U.; Martyniak, J.; Masson, S.; Mavroidis, T.; Maxfield, S. J.; McMahon, S. J.; Mehta, A.; Meier, K.; Mercer, D.; Merz, T.; Meyer, C. A.; Meyer, H.; Meyer, J.; Mikocki, S.; Milstead, D.; Moreau, F.; Morris, J. V.; Müller, G.; Müller, K.; Murín, P.; Nagovizin, V.; Nahnhauer, R.; Naroska, B.; Naumann, Th.; Newman, P. R.; Newton, D.; Neyret, D.; Nguyen, H. K.; Niebergall, F.; Niebuhr, C.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg-Werther, M.; Oberlack, H.; Obrock, U.; Olsson, J. E.; Panaro, E.; Panitch, A.; Pascaud, C.; Patel, G. D.; Peppel, E.; Perez, E.; Phillips, J. P.; Pichler, Ch.; Pitzl, D.; Pope, G.; Prell, S.; Prosi, R.; Rädel, G.; Raupach, F.; Reimer, P.; Reinshagen, S.; Ribarics, P.; Rick, H.; Riech, V.; Riedlberger, J.; Riess, S.; Rietz, M.; Robertson, S. M.; Robmann, P.; Roloff, H. E.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rüter, K.; Rusakov, S.; Rybicki, K.; Rylko, R.; Sahlmann, N.; Sanchez, E.; Sankey, D. P. C.; Savitsky, M.; Schacht, P.; Schiek, S.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmidt, G.; Schöning, A.; Schröder, V.; Schuhmann, E.; Schwab, B.; Schwind, A.; Seehausen, U.; Sefkow, F.; Seidel, M.; Sell, R.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Shtarkov, L. N.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorni, I. O.; Smirnov, P.; Smith, J. R.; Soloviev, Y.; Spitzer, H.; Starosta, R.; Steenbock, M.; Steffen, P.; Steinberg, R.; Stella, B.; Stephens, K.; Stier, J.; Stiewe, J.; Stösslein, U.; Strachota, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Tapprogge, S.; Taylor, R. E.; Tchernyshov, V.; Thiebaux, C.; Thompson, G.; Truöl, P.; Turnau, J.; Tutas, J.; Uelkes, P.; Usik, A.; Valkár, S.; Valkárová, A.; Vallée, C.; Van Esch, P.; Van Mechelen, P.; Vartapetian, A.; Vazdik, Y.; Vecko, M.; Verrecchia, P.; Villet, G.; Wacker, K.; Wagener, A.; Wagener, M.; Walker, I. W.; Walther, A.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wellisch, H. P.; West, L. R.; Willard, S.; Winde, M.; Winter, G.-G.; Wright, A. E.; Wünsch, E.; Wulff, N.; Yiou, T. P.; Žáček, J.; Zarbock, D.; Zhang, Z.; Zhokin, A.; Zimmer, M.; Zimmermann, W.; Zomer, F.; Zuber, K.

    1995-02-01

    Events with no hadronic energy flow in a large interval of pseudo-rapidity in the proton direction are observed in photon-proton interactions at an average centre of mass energy <√s γp> of 200 GeV These events are interpreted as photon diffractive dissociation. Evidence for hard scattering in photon diffractive dissociation is demonstrated using inclusive single particle spectra, thrust as a function of transverse energy, and the observation of jet production. The data can be described by a Monte Carlo calculation including hard photon-pomeron scattering.

  6. What did we learn about GPDs from hard exclusive electroproduction of mesons

    SciTech Connect

    Kroll, Peter

    2011-10-24

    It is reported on an analysis of electroproduction of light mesons at small Bjorken-x (x{sup Bj}) within the handbag approach. The partonic subprocesses, meson electroproduction off quarks or gluons, are calculated within the modified per-turbative approach (m.p.a.) in which quark transverse momenta are retained. The soft hadronic matrix elements, generalized parton distributions (GPDs), are constructed by means of double distributions. The constraints from parton distributions and sum rules are taken into account. Various moments of these GPDs are compared to recent results from lattice gauge theories.

  7. Transverse energy circulation and the edge diffraction of an optical vortex beam.

    PubMed

    Bekshaev, Aleksandr Ya; Mohammed, Kadhim A; Kurka, Ivan A

    2014-04-01

    Edge diffraction of a circular Laguerre-Gaussian beam represents an example of the optical vortex symmetry breakdown in which the hidden "vortex" energy circulation is partially transformed into the visible "asymmetry" form. The diffracted beam evolution is studied in terms of the irradiance moments and the moment-based parameters. In spite of the limited applicability of the moment-based formalism, we show that the "vortex" and "asymmetry" parts of the orbital angular momentum can still be reasonably defined for the hard-edge diffracted beams and retain their physical role of quantifying the corresponding forms of the transverse energy circulation.

  8. Diffractive hadroproduction of W{sup {+-}} and Z{sup 0} bosons at high energies

    SciTech Connect

    Ducati, M. B. Gay; Machado, M. M.; Machado, M. V. T.

    2008-10-13

    An analysis of W{sup {+-}} and Z{sup 0} hard diffractive hadroproduction at high energies is presented obtained using the simple assumption of Regge factorization and considering the recent diffractive parton density functions extracted by the H1 Collaboration at DESY-HERA. The corresponding multiple Pomeron exchange corrections to the single Pomeron one is considered by taking into account by a gap survival probability factor. It is shown that the ratio of diffractive to nondiffractive boson production is in good agreement with the Tevatron data. Estimations which are relevant for the incoming measurements at the LHC are discussed.

  9. Diffractive hadroproduction of W{sup {+-}} and Z{sup 0} bosons at high energies

    SciTech Connect

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T.

    2007-06-01

    Results from a phenomenological analysis of W and Z hard diffractive hadroproduction at high energies are reported. Using the Regge factorization approach, we consider the recent diffractive parton density functions extracted by the H1 Collaboration at DESY-HERA. In addition, we take into account multiple Pomeron exchange corrections considering a gap survival probability factor. It is found that the ratio of diffractive to nondiffractive boson production is in good agreement with the CDF and D0 data. We make predictions which could be compared to future measurements at the LHC.

  10. Self-standing quasi-mosaic crystals for focusing hard X-rays

    NASA Astrophysics Data System (ADS)

    Camattari, Riccardo; Guidi, Vincenzo; Bellucci, Valerio; Neri, Ilaria; Frontera, Filippo; Jentschel, Michael

    2013-05-01

    A quasi mosaic bent crystal for high-resolution diffraction of X and γ rays has been realized. A net curvature was imprinted to the crystal thanks to a series of superficial grooves to keep the curvature without external devices. The crystal highlights very high diffraction efficiency due to quasi mosaic curvature. Quasi mosaic crystals of this kind are proposed for the realization of a high-resolution focusing Laue lens for hard X-rays.

  11. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1974-01-01

    The theory and computer programs, based on electromagnetic theory, for the analysis and design of echelle gratings were developed. The gratings are designed for instruments that operate in the ultraviolet portion of the spectrum. The theory was developed so that the resulting computer programs will be able to analyze deep (up to 30 wavelengths) gratings by including as many as 100 real or homogeneous diffraction orders. The program calculates the complex amplitude coefficient for each of the diffracted orders. A check on the numerical method used to solve the integral equations is provided by a conservation of energy calculation.

  12. Nano-fabricated size exclusion chromatograph

    NASA Technical Reports Server (NTRS)

    Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; Castillo, L. del; White, V.

    2002-01-01

    This paper describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through amicrocolumn containing nano-fabricated features will have characteristic elution times that directly correlate to molecular weight. Compared to conventional size exclusion chromatography, the nSEC offers greater control over the size exclusion process; mass fabrication; integration of the separation column with associated valves, pumps, and detectors; and dramatic reductions in instrument mass and power requirements.

  13. Nano-fabricated size exclusion chromatograph

    NASA Technical Reports Server (NTRS)

    Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; Castillo, L. del; White, V.

    2002-01-01

    This paper describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through amicrocolumn containing nano-fabricated features will have characteristic elution times that directly correlate to molecular weight. Compared to conventional size exclusion chromatography, the nSEC offers greater control over the size exclusion process; mass fabrication; integration of the separation column with associated valves, pumps, and detectors; and dramatic reductions in instrument mass and power requirements.

  14. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  15. Thin coatings and films hardness evaluation

    NASA Astrophysics Data System (ADS)

    Matyunin, V. M.; Marchenkov, A. Yu; Demidov, A. N.; Karimbekov, M. A.

    2016-10-01

    The existing thin coatings and films hardness evaluation methods based on indentation with pyramidal indenter on various scale levels are expounded. The impact of scale factor on hardness values is performed. The experimental verification of several existing hardness evaluation methods regarding the substrate hardness value and the “coating - substrate” composite hardness value is made.

  16. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  17. Effects of calcium and magnesium hardness on the fertilization and hatching success of hybrid catfish eggs

    USDA-ARS?s Scientific Manuscript database

    Hybrid catfish are exclusively produced by strip spawning of channel catfish females, fertilizing stripped eggs with blue catfish sperm, and hatching the fertilized eggs. As egg development takes outside the fish’s body, water hardness is one abioitic parameter, suggested to have a major effect on ...

  18. 7 CFR 520.5 - Categorical exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... implementation which are related to routine activities such as personnel, organizational changes or similar... agency. (c) Exceptions to categorical exclusions. An environmental assessment shall be prepared for an...

  19. Central exclusive production at RHIC

    DOE PAGES

    Adamczyk, Leszek; Guryn, Włodek; Turnau, Jacek

    2014-11-10

    The present status and future plans of the physics program of Central Exclusive Production (CEP) at RHIC are described. The measurements are based on the detection of the forward protons from the Double Pomeron Exchange (DPE) process in the Roman Pot system and of the recoil system of charged particles from the DPE process measured in the STAR experiment’s Time Projection Chamber (TPC). The data described here were taken using polarized proton-proton collisions at ps = 200 GeV. The preliminary spectra of two pion and four pion invariant mass reconstructed by STAR TPC in central region of pseudo-rapidity | |more » < 1, are presented. Near future plans to take data with the current system at center-of-mass energy ps = 200 GeV and plans to upgrade the forward proton tagging sys- tem are presented. Also a possible addition of the Roman Pots to the sPHENIX detector is discussed.« less

  20. Single Photon diffraction and interference

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2015-04-01

    A previous paper based on the Scalar Theory of Everything studied photon diffraction and interference (IntellectualArchive, Vol.1, No. 3, P. 20, Toronto, Canada July 2012. http://intellectualarchive.com/?link=item&id=597). Several photons were required in the experiment at the same time. Interference experiments with one photon in the experiment at a time also showed interference patterns. The previous paper with the Bohm Interpretation, models of the screen and mask, and the Transaction Interpretation of Quantum Mechanics were combined. The reverse wave required by the Transaction Interpretation was provided by a reflected plenum wave rather than a reverse time wave. The speed of the plenum wave was assumed to be much faster than the speed of photons/light. Using the assumptions of Fraunhofer diffraction resulted in the same equation for the photon distribution on a screen as the intensity pattern of the Fraunhofer diffraction. (http://myplace.frontier.com/ ~ jchodge/)

  1. AD, the ALICE diffractive detector

    NASA Astrophysics Data System (ADS)

    Tello, Abraham Villatoro

    2017-03-01

    ALICE is one of the four large experiments at the CERN Large Hadron Collider (LHC). As a complement to its Heavy-Ion physics program, ALICE started during Run 1 of LHC an extensive program dedicated to the study of proton-proton diffractive processes. In order to optimize its trigger efficiencies and purities in selecting diffractive events, the ALICE Collaboration installed a very forward AD detector during the Long Shut Down 1 of LHC. This new forward detector system consists of two stations made of two layers of scintillator pads, one station on each side of the interaction point. With this upgrade, ALICE has substantially increased its forward physics coverage, including the double rapidity gap based selection of central production, as well as the measurements of inclusive diffractive cross sections.

  2. Electron diffraction by plasmon waves

    NASA Astrophysics Data System (ADS)

    García de Abajo, F. J.; Barwick, B.; Carbone, F.

    2016-07-01

    An electron beam traversing a structured plasmonic field is shown to undergo diffraction with characteristic angular patterns of both elastic and inelastic outgoing electron components. In particular, a plasmonic grating (e.g., a standing wave formed by two counterpropagating plasmons in a thin film) produces diffraction orders of the same parity as the net number of exchanged plasmons. Large diffracted beam fractions are predicted to occur for realistic plasmon intensities in attainable geometries due to a combination of phase and amplitude changes locally imprinted on the passing electron wave. Our study opens vistas in the study of multiphoton exchanges between electron beams and evanescent optical fields with unexplored effects related to the transversal component of the electron wave function.

  3. X-ray Diffraction as a Means to Assess Fatigue Performance of Shot-Peened Materials

    DTIC Science & Technology

    2012-06-01

    titanium 6 - 4 fatigue data exhibited similar trends to the 9310 steel material. Low shot- peening intensities (4A and 8A) improved fatigue performance... 6 Figure 4 ...7 Figure 4 . Residual stress and diffraction peak width data from the beta-STOA titanium 6Al-4V disks. attributed to the hardness of the

  4. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-02

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included.

  5. Lamellar multilayer gratings with very high diffraction efficiency

    SciTech Connect

    Martynov, V.V. |; Yakshin, A.; Agafonov, Yu.A.; Padmore, H.A.

    1997-07-01

    The authors report here the development of a hard x-ray multilayer grating that has achieved an absolute efficiency of 34% at a wavelength of 1.54{angstrom}. The W-C multilayer itself has a reflectivity of 57% and the grating has a 0th order absolute efficiency of 36%. The origin of this extraordinarily high efficiency is that the short period and highly asymmetric structure of the gratings combined with its deep grooves allows light to interact with a large number of layer pairs. This increases angular separation of the diffraction orders and reduces the multilayer bandwidth to the point where there is little or no order to order overlap in the grating structure, and hence maximum intensity can be diffracted into a selected order. This paper reports on the development of an optimized multilayer grating and some of its unique characteristics.

  6. Algorithmic methods in diffraction microscopy

    NASA Astrophysics Data System (ADS)

    Thibault, Pierre

    Recent diffraction imaging techniques use properties of coherent sources (most notably x-rays and electrons) to transfer a portion of the imaging task to computer algorithms. "Diffraction microscopy" is a method which consists in reconstructing the image of a specimen from its diffraction pattern. Because only the amplitude of a wavefield incident on a detector is measured, reconstruction of the image entails to recovering the lost phases. This extension of the 'phase problem" commonly met in crystallography is solved only if additional information is available. The main topic of this thesis is the development of algorithmic techniques in diffraction microscopy. In addition to introducing new methods, it is meant to be a review of the algorithmic aspects of the field of diffractive imaging. An overview of the scattering approximations used in the interpretation of diffraction datasets is first given, as well as a numerical propagation tool useful in conditions where known approximations fail. Concepts central to diffraction microscopy---such as oversampling---are then introduced and other similar imaging techniques described. A complete description of iterative reconstruction algorithms follows, with a special emphasis on the difference map, the algorithm used in this thesis. The formalism, based on constraint sets and projection onto these sets, is then defined and explained. Simple projections commonly used in diffraction imaging are then described. The various ways experimental realities can affect reconstruction methods will then be enumerated. Among the diverse sources of algorithmic difficulties, one finds that noise, missing data and partial coherence are typically the most important. Other related difficulties discussed are the detrimental effects of crystalline domains in a specimen, and the convergence problems occurring when the support of a complex-valued specimen is not well known. The last part of this thesis presents reconstruction results; an

  7. Diffraction-induced coherence levels.

    PubMed

    Tavrov, Alexander; Schmit, Joanna; Kerwien, Norbert; Osten, Wolfgang; Tiziani, Hans

    2005-04-10

    We examined the influence of complex diffraction effects on low-coherence fringes created for high-aspect depth-to-width ratio structures called trenches. The coherence function was analyzed for these micrometer-wide trenches and was registered with a white-light interference microscope. For some types of surface structure we observed that additional low-coherence fringes that do not correspond directly to the surface topology are formed near the sharp edges of the structures. These additional coherence fringes were studied by rigorous numerical evaluations of vector diffractions, and these simulated interference fields were then compared with experimental results that were obtained with a white-light interference microscope.

  8. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, Richard J.

    1991-01-01

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.

  9. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, R.J.

    1991-09-24

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection. 3 figures.

  10. High-pressure neutron diffraction

    SciTech Connect

    Xu, Hongwu

    2011-01-10

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  11. Cryogenic X-Ray Diffraction Microscopy for Biological Samples

    SciTech Connect

    Lima, Enju; Wiegart, Lutz; Pernot, Petra; Howells, Malcolm; Timmins, Joanna; Zontone, Federico; Madsen, Anders

    2009-11-06

    X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

  12. Diffraction as a critical element in soft scattering

    NASA Astrophysics Data System (ADS)

    Maor, Uri

    2016-10-01

    Gribov’s partonic Pomeron provides the foundations of updated models which incorporate soft and hard scattering, so as to reproduce the recent LHC p-p cross sections. Explicitly, total, elastic, inelastic and diffrative data. Leading models are: GLM (Gotsman, Levin, Maor), KMR (Khoze, Martin, Ryskin), Kaidalov-Poghosyan and Ostapchenco. None of these models in their pre-LHC versions reproduced the TOTEM, ALICE, ATLAS and CMS soft LHC data, needing considerable reconstructions, either in the fitting procedures (GLM), or in the details of the theoretical models. In the following, I shall relate mostly to the GLM model, emphasizing the critical role of the diffractive channels.

  13. Diffraction as a Critical Element in Soft Scattering

    NASA Astrophysics Data System (ADS)

    Maor, Uri

    Gribov's partonic Pomeron provides the foundations of updated models which incorporate soft and hard scattering, so as to reproduce the recent LHC p-p cross sections. Explicitly, total, elastic, inelastic and diffrative data. Leading models are: GLM (Gotsman, Levin, Maor), KMR (Khoze, Martin, Ryskin), Kaidalov-Poghosyan and Ostapchenco. None of these models in their pre-LHC versions reproduced the TOTEM, ALICE, ATLAS and CMS soft LHC data, needing considerable reconstructions, either in the fitting procedures (GLM), or in the details of the theoretical models. In the following, I shall relate mostly to the GLM model, emphasizing the critical role of the diffractive channels.

  14. A multispecies exclusion model inspired by transcriptional interference

    NASA Astrophysics Data System (ADS)

    Ghosh, Soumendu; Bameta, Tripti; Ghanti, Dipanwita; Chowdhury, Debashish

    2016-12-01

    We introduce exclusion models of two distinguishable species of hard rods with their distinct sites of entry and exit under open boundary conditions. In the first model both species of rods move in the same direction whereas in the other two models they move in the opposite direction. These models are motivated by the biological phenomenon known as transcriptional interference. Therefore, the rules for the kinetics of the models, particularly the rules for the outcome of the encounter of the rods, are also formulated to mimic those observed in transcriptional interference. By a combination of mean-field theory and computer simulation of these models we demonstrate how the flux of one species of rods is completely switched off by the other. Exploring the parameter space of the model we also establish the conditions under which switch-like regulation of two fluxes is possible; from the extensive analysis we discover more than one possible mechanism of this phenomenon.

  15. Nanoindentation hardness of mineralized tissues.

    PubMed

    Oyen, Michelle L

    2006-01-01

    A series elastic and plastic deformation model [Sakai, M., 1999. The Meyer hardness: a measure for plasticity? Journal of Materials Research 14(9), 3630-3639] is used to deconvolute the resistance to plastic deformation from the plane strain modulus and contact hardness parameters obtained in a nanoindentation test. Different functional dependencies of contact hardness on the plane strain modulus are examined. Plastic deformation resistance values are computed from the modulus and contact hardness for engineering materials and mineralized tissues. Elastic modulus and plastic deformation resistance parameters are used to calculate elastic and plastic deformation components, and to examine the partitioning of indentation deformation between elastic and plastic. Both the numerical values of plastic deformation resistance and the direct computation of deformation partitioning reveal the intermediate mechanical responses of mineralized composites when compared with homogeneous engineering materials.

  16. Edge diffracted caustic fields. [spacecraft antenna radiation patterns

    NASA Technical Reports Server (NTRS)

    Burnside, W. D.; Peters, L., Jr.

    1974-01-01

    The fields near a caustic created by an edge diffraction process are computed using the equivalent current concept. These fields are shown to have the property commonly associated with ray optical analysis or the Geometrical Theory of Diffraction (GTD), e.g., a 90 deg phase shift as the ray passes through the caustic. The present effort is directed toward consideration of the caustic created by an edge diffraction process. Particular attention is focused on electromagnetic excitation. The acoustic excitation for the hard boundary condition is outlined in an appendix. In addition, goal is to establish the extent of the caustic region. This is of particular importance when a ray optical solution involves multiply-diffracted terms in that the minimum size of the body that can be analyzed may be restricted by the extent of the caustic, i.e., the 90 deg phase shift used in ray optical analysis may be introduced only if the caustic is contained on the surface being studied.

  17. Spatiotemporal response of crystals in x-ray Bragg diffraction

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri; Lindberg, Ryan

    2012-10-01

    The spatiotemporal response of crystals in x-ray Bragg diffraction resulting from excitation by an ultrashort, laterally confined x-ray pulse is studied theoretically. The theory presents an extension of the analysis in symmetric reflection geometry [R. R. Lindberg and Y. V. Shvyd’ko, Phys. Rev. ST Accel. Beams 15, 050706 (2012)PRABFM1098-440210.1103/PhysRevSTAB.15.050706] to the generic case, which includes Bragg diffraction both in reflection (Bragg) and transmission (Laue) asymmetric scattering geometries. The spatiotemporal response is presented as a product of a crystal-intrinsic plane-wave spatiotemporal response function and an envelope function defined by the crystal-independent transverse profile of the incident beam and the scattering geometry. The diffracted wave fields exhibit amplitude modulation perpendicular to the propagation direction due to both angular dispersion and the dispersion due to Bragg’s law. The characteristic measure of the spatiotemporal response is expressed in terms of a few parameters: the extinction length, crystal thickness, Bragg angle, asymmetry angle, and the speed of light. Applications to self-seeding of hard x-ray free-electron lasers are discussed, with particular emphasis on the relative advantages of using either the Bragg or Laue scattering geometries. Intensity front inclination in asymmetric diffraction can be used to make snapshots of ultrafast processes with femtosecond resolution.

  18. Strong exchange coupling in conventional and inverse ferrimagnetic hard/soft and soft/hard core/shell heterostructured nanoparticles

    NASA Astrophysics Data System (ADS)

    Nogues, Josep

    2013-03-01

    Bi-magnetic core/shell nanoparticles are becoming increasingly appealing for diverse fields such as for permanent magnets, microawave absortion, biomedical applications, sensing applications, or future magnetic recording media. Ferrromagnetic (FM)/ antiferromagnetic (AFM) core/shell nanoparticles (or inverted AFM/FM) have been extensively studied. However, exchange coupled hard/soft, or inverse soft/hard, core/shell nanoparticles have been far less investigated. Interestingly, most bi-magnetic core/shell systems are derived by simple partial oxidation of the core, e.g., Co/CoO (FM/AFM) or FePt/Fe3O4 (hard/soft) and only few studies of heterostructured (where core and shell are formed by different magnetic ions) can be found in the literature. We have investigated conventional hard/soft and inverted soft/hard core/shell hetroestructured nanoparticles based on magnetically soft iron oxide (Fe3O4) and magnetically hard manganese oxide (Mn3O4) . The core/shell samples were synthesized by seeded growth using either Fe3O4 or Mn3O4 nanoparticles as seeds. Subsequently, thin layers of the complementary material were grown by thermal decomposition of the corresponding metallorganic precursors. The structure characterization (X-ray diffraction and electron diffraction) confirms the presence of cubic (Fe3O4) and tetragonal (Mn3O4) phases both at the bulk and local levels. In addition, high resolution transmission electron microscopy (HR-TEM) with electron energy loss spectroscopy (EELS) mapping confirms the core/shell structure of the nanopartciles. Magnetic characterization and element-selective hysteresis loops obtained by x-ray magnetic circular dichroism (XMCD) reveal a strong exchange coupling between the core and the shell which results in homogeneous loops with moderate coercivity. Moreover, the magnetic properties can be tuned by controlling the core diameter or shell thickness. However, the results depend only weakly on the hard/soft or inverse soft/hard morphology

  19. Exclusive Hyperon Production at CLAS

    NASA Astrophysics Data System (ADS)

    Carman, Daniel

    2009-10-01

    This talk will provide an overview of the exclusive hyperon production experiments being carried out by the CLAS Collaboration at Jefferson Laboratory. The program is designed to measure cross sections and a complete set of beam, target, and recoil hyperon polarization observables for both Kλ and Kσ final states with beam energies up to 6 GeV. These data will span a broad kinematic range in momentum transfer Q^2 and invariant energy W, and nearly the full center-of-mass angular range of the kaon. Analyses of data on both proton and neutron targets are underway or planned for the near future involving polarized beams (longitudinally polarized electrons, circularly and linearly polarized photons) and polarized targets (longitudinally and transversely polarized). The main goal of this series of measurements is to provide precision data needed to disentangle the resonant and non-resonant amplitudes in the intermediate state to uncover baryon resonances that couple to the strangeness channels (N^* ->Kλ, Kσ, &*circ;->Kσ). This will improve our understanding of the nucleon excitation spectrum, and hence, probe the effective degrees of freedom of the nucleon. These data will also serve to improve our understanding of the dynamics underlying strangeness production in general. Over the next several years it is expected that a full coupled-channels analysis, including hadroproduction data, as well as data with both real and virtual photons, will be completed by several groups, including the Excited Baryon Analysis Center (EBAC) at Jefferson Laboratory. The precision data from CLAS will be a crucial input for these analyses. Within the next five years, the CLAS facility will be significantly upgraded for use with the higher-energy electron beams available with the 12-GeV Jefferson Laboratory energy upgrade. The future of the strangeness physics program with the new CLAS12 facility will be highlighted.

  20. Leading twist nuclear shadowing phenomena in hard processes with nuclei

    DOE PAGES

    L. Franfurt; Guzey, V.; Strikman, M.

    2012-01-08

    We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei-inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering - and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We alsomore » analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It will be possible to check many of our predictions in the near future in the studies of the ultraperipheral collisions at the Large Hadron Collider (LHC). Further checks will be possible in pA collisions at the LHC and forward hadron production at Relativistic Heavy Ion Collider (RHIC). As a result, detailed tests will be possible at an Electon-Ion Collider (EIC) in USA and at the Large Hadron-Electron Collider (LHeC) at CERN.« less

  1. Leading twist nuclear shadowing phenomena in hard processes with nuclei

    SciTech Connect

    L. Franfurt; Guzey, V.; Strikman, M.

    2012-01-08

    We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei-inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering - and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We also analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It will be possible to check many of our predictions in the near future in the studies of the ultraperipheral collisions at the Large Hadron Collider (LHC). Further checks will be possible in pA collisions at the LHC and forward hadron production at Relativistic Heavy Ion Collider (RHIC). As a result, detailed tests will be possible at an Electon-Ion Collider (EIC) in USA and at the Large Hadron-Electron Collider (LHeC) at CERN.

  2. Effect of homogenization process on the hardness of Zn-Al-Cu alloys

    NASA Astrophysics Data System (ADS)

    Villegas-Cardenas, Jose D.; Saucedo-Muñoz, Maribel L.; Lopez-Hirata, Victor M.; De Ita-De la Torre, Antonio; Avila-Davila, Erika O.; Gonzalez-Velazquez, Jorge Luis

    2015-10-01

    The effect of a homogenizing treatment on the hardness of as-cast Zn-Al-Cu alloys was investigated. Eight alloy compositions were prepared and homogenized at 350 °C for 180 h, and their Rockwell "B" hardness was subsequently measured. All the specimens were analyzed by X-ray diffraction and metallographically prepared for observation by optical microscopy and scanning electron microscopy. The results of the present work indicated that the hardness of both alloys (as-cast and homogenized) increased with increasing Al and Cu contents; this increased hardness is likely related to the presence of the θ and τ' phases. A regression equation was obtained to determine the hardness of the homogenized alloys as a function of their chemical composition and processing parameters, such as homogenization time and temperature, used in their preparation.

  3. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout...

  4. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout...

  5. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout...

  6. 12 CFR 229.42 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Exclusions. 229.42 Section 229.42 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Collection of Checks § 229.42 Exclusions....

  7. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  8. 47 CFR 76.107 - Exclusivity contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Exclusivity contracts. 76.107 Section 76.107 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports...

  9. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  10. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  11. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  12. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  13. 10 CFR 830.2 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Exclusions. 830.2 Section 830.2 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT § 830.2 Exclusions. This part does not apply to: (a) Activities that are... 1974, as amended; and (e) Activities related to the launch approval and actual launch of nuclear...

  14. 47 CFR 73.232 - Territorial exclusivity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Territorial exclusivity. 73.232 Section 73.232 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.232 Territorial exclusivity. No licensee of an FM broadcast station shall have...

  15. 47 CFR 73.232 - Territorial exclusivity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Territorial exclusivity. 73.232 Section 73.232 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.232 Territorial exclusivity. No licensee of an FM broadcast station shall have...

  16. 18 CFR 1308.3 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Exclusions. 1308.3 Section 1308.3 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES General Matters § 1308.3 Exclusions. (a) This part does not apply to any TVA contract which does not...

  17. 18 CFR 1308.3 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Exclusions. 1308.3 Section 1308.3 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES General Matters § 1308.3 Exclusions. (a) This part does not apply to any TVA contract which does not...

  18. 18 CFR 1308.3 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Exclusions. 1308.3 Section 1308.3 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES General Matters § 1308.3 Exclusions. (a) This part does not apply to any TVA contract which does not...

  19. 18 CFR 1308.3 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Exclusions. 1308.3 Section 1308.3 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES General Matters § 1308.3 Exclusions. (a) This part does not apply to any TVA contract which does not...

  20. 18 CFR 1308.3 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Exclusions. 1308.3 Section 1308.3 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES General Matters § 1308.3 Exclusions. (a) This part does not apply to any TVA contract which does not...

  1. Exclusion from School and Recognition of Difference

    ERIC Educational Resources Information Center

    McCluskey, Gillean; Riddell, Sheila; Weedon, Elisabet; Fordyce, Mariela

    2016-01-01

    There has been an overall decrease in exclusion rates and numbers in recent years across the UK. This change has often been heralded as evidence that national inclusion policies are "working" and that schools themselves are becoming increasingly inclusive. This article examines findings from a recent study on school exclusion in Wales,…

  2. 36 CFR 907.10 - Categorical exclusion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENVIRONMENTAL QUALITY § 907.10 Categorical exclusion. The CEQ Regulations provide for the categorical exclusion... to this part, following public comment and review by the Council on Environmental Quality. ... human environment. Therefore, neither an environmental assessment nor an environmental impact statement...

  3. 36 CFR 907.10 - Categorical exclusion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENVIRONMENTAL QUALITY § 907.10 Categorical exclusion. The CEQ Regulations provide for the categorical exclusion... to this part, following public comment and review by the Council on Environmental Quality. ... human environment. Therefore, neither an environmental assessment nor an environmental impact statement...

  4. 49 CFR 236.911 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Exclusions. 236.911 Section 236.911 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... Train Control Systems § 236.911 Exclusions. (a) Does this subpart apply to existing systems? The...

  5. 49 CFR 236.911 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Exclusions. 236.911 Section 236.911 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... Train Control Systems § 236.911 Exclusions. (a) Does this subpart apply to existing systems? The...

  6. 49 CFR 236.911 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Exclusions. 236.911 Section 236.911 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... Train Control Systems § 236.911 Exclusions. (a) Does this subpart apply to existing systems? The...

  7. 49 CFR 236.911 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Exclusions. 236.911 Section 236.911 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... Train Control Systems § 236.911 Exclusions. (a) Does this subpart apply to existing systems? The...

  8. 49 CFR 236.911 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Exclusions. 236.911 Section 236.911 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... Train Control Systems § 236.911 Exclusions. (a) Does this subpart apply to existing systems? The...

  9. Women Combat Exclusion Policy: Relevant or Obsolete?

    DTIC Science & Technology

    2012-03-22

    to physically collocate and remain with direct ground combat units that are closed to women ; where units are engaged in long range reconnaissance... Women Combat Exclusion Policy: Relevant or Obsolete? by Lieutenant Colonel Melinda S. Romero United States Army...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Women Combat Exclusion Policy: Relevant or Obsolete? 5b. GRANT NUMBER 5c

  10. 32 CFR 536.46 - Other exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Other exclusions. 536.46 Section 536.46 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS CLAIMS AGAINST THE UNITED STATES Investigation and Processing of Claims § 536.46 Other exclusions. (a) Statutory employer....

  11. 47 CFR 1.6005 - Exclusive defenses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Exclusive defenses. 1.6005 Section 1.6005... Against Satellite Carriers for Retransmission Without Consent § 1.6005 Exclusive defenses. (a) The defenses listed in paragraphs (a)(1) through (a)(4) of this section, are the only defenses available to a...

  12. 47 CFR 1.6005 - Exclusive defenses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Exclusive defenses. 1.6005 Section 1.6005... Against Satellite Carriers for Retransmission Without Consent § 1.6005 Exclusive defenses. (a) The defenses listed in paragraphs (a)(1) through (a)(4) of this section, are the only defenses available to a...

  13. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Exclusions. 19.1504 Section 19.1504 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This subpart...

  14. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Exclusions. 19.1504 Section 19.1504 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This subpart...

  15. 40 CFR 68.126 - Exclusion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Exclusion. 68.126 Section 68.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.126 Exclusion...

  16. 40 CFR 68.126 - Exclusion.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Exclusion. 68.126 Section 68.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.126 Exclusion...

  17. 40 CFR 68.126 - Exclusion.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Exclusion. 68.126 Section 68.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.126 Exclusion...

  18. 40 CFR 68.126 - Exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Exclusion. 68.126 Section 68.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.126 Exclusion...

  19. 40 CFR 68.126 - Exclusion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Exclusion. 68.126 Section 68.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.126 Exclusion...

  20. 48 CFR 19.1006 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Exclusions. 19.1006 Section 19.1006 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Small Business Competitiveness Demonstration Program 19.1006 Exclusions...

  1. 24 CFR 58.35 - Categorical exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification § 58.35 Categorical exclusions. Categorical exclusion refers to a category of activities for which no environmental... needed with respect to environmental requirements, except where paragraph (c) of this section...

  2. Rescinding the Ground Combat Exclusion Policy

    DTIC Science & Technology

    2011-04-07

    Miller, " Feminism and the Exclusion of Army Women from Combat," in Women in the Military, ed. Rita James Simon (New Brunswick, NJ: Transaction...index.php/issuepapers (accessed November 23, 2010). Miller, Laura L. " Feminism and the Exclusion of Army Women from Combat." In Women in the Military

  3. 12 CFR 367.5 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... EXCLUSION OF CONTRACTOR AND TERMINATION OF CONTRACTS § 367.5 Exclusions. (a) The Ethics Counselor may... also prohibited from conducting business with FDIC as agents or representatives of other contractors... Ethics Counselor's decision to exclude the contractor pursuant to § 367.16. Provided further, that...

  4. Neutron diffraction studies of bacteriorhodopsin

    SciTech Connect

    Trewhella, J.; Popot, J.L.; Engelman, D.M.; Zaccai, G.

    1985-01-01

    Neutron diffraction studies of bacteriorhodopsin have utilized the entire range of deuterium labeling techniques that are commonly used in biological neutron scattering experiments. We will review the work published in this area and report on current projects. 10 refs., 1 fig.

  5. Diffraction Plates for Classroom Demonstrations

    ERIC Educational Resources Information Center

    Hoover, Richard B.

    1969-01-01

    Describes the computer generation of random and regular arrays of apertures on photographic film and their applications for classroom demonstrations of the Fraunhofer patterns produced by simple and complex apertures, Babinet's principle, resolution according to the Rayleigh criterion, and many other aspects of diffraction. (LC)

  6. Fresnel Diffraction for CTR Microbunching

    SciTech Connect

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B.; Andonian, G.

    2009-01-22

    Laser beams of high intensities are routinely used for IFEL experiments. Such beams can potentially destroy microbunching diagnostic tools such as coherent transition radiation foils due to their low damage thresholds. Near-field Fresnel diffraction scheme for termination of CO{sub 2} laser beam has been experimentally studied and is presented in this paper. Novel THz camera was utilized for such study.

  7. Diffractive corneal inlay for presbyopia.

    PubMed

    Furlan, Walter D; García-Delpech, Salvador; Udaondo, Patricia; Remón, Laura; Ferrando, Vicente; Monsoriu, Juan A

    2017-09-01

    A conceptually new type of corneal inlays for a customized treatment of presbyopia is presented. The diffractive inlay consists on a small aperture disc having an array of micro-holes distributed inside the open zones of a Fresnel zone plate. In this way, the central hole of the disc lets pass the zero order diffraction and produces an extension of the depth of far focus of the eye, while the diffracted light through the holes in the periphery produce the near focus. Additionally, the micro-holes in the inlay surface fulfill the essential requirement of allowing the flow of nutrients through it to the cells of the corneal stroma. Theoretical and optical-bench experimental results for the polychromatic axial Point Spread Function (PSF) were obtained, showing an improved performance compared to the small aperture corneal inlay currently in the market (Kamra). Images of a test object, obtained at several vergences in the surroundings of the far and near foci, are also shown. Picture: Simulation of the appearance of the Diffractive corneal inlay on a real eye. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Fresnel Diffraction for CTR Microbunching

    NASA Astrophysics Data System (ADS)

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B.; Andonian, G.

    2009-01-01

    Laser beams of high intensities are routinely used for IFEL experiments. Such beams can potentially destroy microbunching diagnostic tools such as coherent transition radiation foils due to their low damage thresholds. Near-field Fresnel diffraction scheme for termination of CO2 laser beam has been experimentally studied and is presented in this paper. Novel THz camera was utilized for such study.

  9. Mathmatical modeling for diffractive optics

    NASA Technical Reports Server (NTRS)

    Dobson, David; Cox, J. Allen

    1993-01-01

    We consider a 'diffractive optic' to be a biperiodic surface separating two half-spaces, each having constant constitutive parameters; within a unit cell of the periodic surface and across the transition zone between the two half-spaces, the constitutive parameters can be a continuous, complex-valued function. Mathematical models for diffractive optics have been developed, and implemented as numerical codes, both for the 'direct' problem and for the 'inverse' problem. In problems of the 'direct' class, the diffractive optic is specified, and the full set of Maxwell's equations is cast in a variational form and solved numerically by a finite element approach. This approach is well-posed in the sense that existence and uniqueness of the solution can be proved and specific convergence conditions can be derived. An example of a metallic grating at a Wood anomaly is presented as a case where other approaches are known to have convergence problems. In problems of the 'inverse' class, some information about the diffracted field (e.g., the far-field intensity) is given, and the problem is to find the periodic structure in some optimal sense. Two approaches are described: phase reconstruction in the far-field approximation; and relaxed optimal design based on the Helmholtz equation. Practical examples are discussed for each approach to the inverse problem, including array generators in the far-field case and antireflective structures for the relaxed optimal design.

  10. Fresnel diffraction plates are simple and inexpensive

    NASA Technical Reports Server (NTRS)

    Hoover, R. B.

    1967-01-01

    Fresnel plate demonstrates diffraction phenomena simply and inexpensively. A large number of identical diffracting apertures are made in random orientation on photographic film. When a small source of light is viewed through the plate, the diffraction pattern typical of the diffracting aperture is readily seen.

  11. Electro-Optic Diffraction Grating Tuned Laser.

    DTIC Science & Technology

    The patent concerns an electro - optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro - optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating. An optional angle multiplier may be used between the electro - optic diffraction grating and the reflective grating.

  12. Stratified volume diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Chambers, Diana Marie

    2000-11-01

    Gratings with high diffraction efficiency into a single order find use in applications ranging from optical interconnects to beam steering. Such gratings have been realized with volume holographic, blazed, and diffractive optical techniques. However, each of these methods has limitations that restrict the range of applications in which they can be used. In this work an alternate, novel approach and method for creating high efficiency gratings has been developed. These new gratings are named stratified volume diffractive optical elements (SVDOE's). In this approach diffractive optic techniques are used to create an optical structure that emulates volume grating behavior. An SVDOE consists of binary gratings interleaved with homogeneous layers in a multi-layer, stratified grating structure. The ridges of the binary gratings form fringe planes analogous to those of a volume hologram. The modulation and diffraction of an incident beam, which occur concurrently in a volume grating, are achieved sequentially by the grating layers and the homogeneous layers, respectively. The layers in this type of structure must be fabricated individually, which introduces the capability to laterally shift the binary grating layers relative to one another to create a grating with slanted fringe planes. This allows an element to be designed with high diffraction efficiency into the first order for any arbitrary angle of incidence. A systematic design process has been developed for SVDOE's. Optimum modulation depth of the SVDOE is determined analytically and the number of grating layers along with the thickness of homogeneous layers is determined by numerical simulation. A rigorous electromagnetic simulation of the diffraction properties of multi-layer grating structures, based on the Rigorous Coupled-Wave Analysis (RCWA) algorithm, was developed and applied to SVDOE performance prediction. Fabrication of an SVDOE structure presents unique challenges. Microfabrication combined with

  13. Infrared Metamaterials for Diffractive Optics

    NASA Astrophysics Data System (ADS)

    Tsai, Yu-Ju

    Intense developments in optical metamaterials have led to a renaissance in several optics fields. Metamaterials, artificially structured media, provide several additional degrees of freedom that cannot be accessed with conventional materials. For example, metamaterials offer a convenient and precise way to explore a wide range of refractive indices, including negative values. In this dissertation, I introduce the idea of metamaterial based diffractive optics. Merging diffractive optics with metamaterials has several benefits, including access to almost continuous phase profiles and a wide range of available controlled anisotropy. I demonstrate this concept with several examples. I begin with an example of metamaterial based blazed diffraction grating using gradient index metamaterials for lambda = 10.6 microm. A series of non-resonant metamaterial elements were designed and fabricated to mimic a saw-tooth refractive index profile with a linear index variation of Deltan = 3.0. The linear gradient profile is repeated periodically to form the equivalent of a blazed grating, with the gradient occurring across a spatial distance of 61 microm. The index gradient is confirmed by comparing the measured magnitudes of the -1, 0 and +1 diffracted orders to those obtained from full wave simulations. In addition to a metamaterial grating, a metamaterial based computer-generated phase hologram was designed by implementing the Gerchberg-Saxton (GS) iterative algorithm to form a 2D phase panel. A three layer metamaterial hologram was fabricated, with the size of 750 microm x 750 microm. Each pixel is comprised of 5 x 5 metamaterial elements. This simple demonstration shows the potential for practical applications of metamaterial based diffractive optics. The demand for compact and integrated optoelectronic systems increases the urgency for optical components that can simultaneously perform various functions. This dissertation also presents an optical element capable of

  14. Exclusion and Education in South Africa: An Education Law Perspective of Emerging Alternative Understandings of Exclusion

    ERIC Educational Resources Information Center

    Beckmann, Johan

    2016-01-01

    The new democratic dispensation in South Africa (1994) was accompanied by law and policy aimed at preventing unfair exclusion from educational opportunities and promoting equal access to educational opportunities. However, feelings of unfair exclusion remain and new understandings of exclusion are emerging. This paper examines the new policy and…

  15. Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

    NASA Astrophysics Data System (ADS)

    Kress, Bernard; Hejmadi, Vic

    2010-05-01

    When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

  16. Ultrafast molecular processes mapped by femtosecond x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Elsaesser, Thomas

    2012-02-01

    X-ray diffraction with a femtosecond time resolution allows for mapping photoinduced structural dynamics on the length scale of a chemical bond and in the time domain of atomic and molecular motion. In a pump-probe approach, a femtosecond excitation pulse induces structural changes which are probed by diffracting a femtosecond hard x-ray pulse from the excited sample. The transient angular positions and intensities of diffraction peaks give insight into the momentary atomic or molecular positions and into the distribution of electronic charge density. The simultaneous measurement of changes on different diffraction peaks is essential for determining atom positions and charge density maps with high accuracy. Recent progress in the generation of ultrashort hard x-ray pulses (Cu Kα, wavelength λ=0.154 nm) in laser-driven plasma sources has led to the implementation of the powder diffraction and the rotating crystal method with a time resolution of 100 fs. In this contribution, we report new results from powder diffraction studies of molecular materials. A first series of experiments gives evidence of a so far unknown concerted transfer of electrons and protons in ammonium sulfate [(NH4)2SO4], a centrosymmetric structure. Charge transfer from the sulfate groups results in the sub-100 fs generation of a confined electron channel along the c-axis of the unit cell which is stabilized by transferring protons from the adjacent ammonium groups into the channel. Time-dependent charge density maps display a periodic modulation of the channel's charge density by low-frequency lattice motions with a concerted electron and proton motion between the channel and the initial proton binding site. A second study addresses atomic rearrangements and charge dislocations in the non-centrosymmetric potassium dihydrogen phosphate [KH2PO4, KDP]. Photoexcitation generates coherent low-frequency motions along the LO and TO phonon coordinates, leaving the average atomic positions unchanged

  17. Coherent Bragg nanodiffraction at the hard X-ray Nanoprobe beamline

    PubMed Central

    Hruszkewycz, S. O.; Holt, M. V.; Maser, J.; Murray, C. E.; Highland, M. J.; Folkman, C. M.; Fuoss, P. H.

    2014-01-01

    Bragg coherent diffraction with nanofocused hard X-ray beams provides unique opportunities for quantitative in situ studies of crystalline structure in nanoscale regions of complex materials and devices by a variety of diffraction-based techniques. In the case of coherent diffraction imaging, a major experimental challenge in using nanoscale coherent beams is maintaining a constant scattering volume such that coherent fringe visibility is maximized and maintained over the course of an exposure lasting several seconds. Here, we present coherent Bragg diffraction patterns measured from different nanostructured thin films at the Sector 26 Nanoprobe beamline at the Advanced Photon Source and demonstrate that with nanoscale positional control, coherent diffraction patterns can be measured with source-limited fringe visibilities more than 50% suitable for imaging by coherent Bragg ptychography techniques. PMID:24470418

  18. Factors associated with latent fingerprint exclusion determinations.

    PubMed

    Ulery, Bradford T; Hicklin, R Austin; Roberts, Maria Antonia; Buscaglia, JoAnn

    2017-02-22

    Exclusion is the determination by a latent print examiner that two friction ridge impressions did not originate from the same source. The concept and terminology of exclusion vary among agencies. Much of the literature on latent print examination focuses on individualization, and much less attention has been paid to exclusion. This experimental study assesses the associations between a variety of factors and exclusion determinations. Although erroneous exclusions are more likely to occur on some images and for some examiners, they were widely distributed among images and examiners. Measurable factors found to be associated with exclusion rates include the quality of the latent, value determinations, analysis minutia count, comparison difficulty, and the presence of cores or deltas. An understanding of these associations will help explain the circumstances under which errors are more likely to occur and when determinations are less likely to be reproduced by other examiners; the results should also lead to improved effectiveness and efficiency of training and casework quality assurance. This research is intended to assist examiners in improving the examination process and provide information to the broader community regarding the accuracy, reliability, and implications of exclusion decisions.

  19. Exclusive production of χ(0) meson and its measurement in the ππ channel

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, P.; Pasechnik, R.; Szczurek, A.

    2011-10-01

    We report on the results of a theoretical study of the central exclusive production of scalar χ(0) meson via χ→ππ decay in high-energy hadron collisions at the RHIC, Tevatron and LHC. The corresponding amplitude for exclusive double-diffractive χ meson production was obtained within the k-factorization approach including virtualities of active gluons and the cross section is calculated with unintegrated gluon distribution functions (UGDFs) known from the literature. The four-body pp→ppππ reaction constitutes an irreducible background to the exclusive χ meson production. We include the absorption effects due to proton-proton interaction and pion-pion rescattering. Several differential distributions for pp(p¯)→pp(p¯)χ process, including the absorptive corrections, were calculated. The influence of kinematical cuts on the signal-to-background ratio is investigated.

  20. Hardness of kamacite and shock histories of 119 meteorites.

    NASA Technical Reports Server (NTRS)

    Jain, A. V.; Gordon, R. B.; Lipschutz, M. E.

    1972-01-01

    Use of metallographic and X-ray diffraction techniques to study the shock histories of 119 iron and stony-iron meteorites, and measurement of the hardness of kamacite in these specimens and in artificially shocked-unannealed and annealed meteorite specimens. Shock increases kamacite hardness, but complications introduced by other physical and chemical properties of meteorites limit its utility as a shock indicator. About 50% of the meteorites studied show evidence for preterrestrial shock loading to pressures of greater than or equal to 130 kb, and 40% have not been shocked to such high pressures. The remaining meteorites have been heat-altered in such a way that their shock histories cannot be determined explicitly. These results, together with those obtained previously, indicate that the plurality, if not the majority, of all iron and stony-iron meteorites sampled by the earth were shocked to pressures of greater than or equal to 130 kb during preterrestrial collisions between asteroidal-sized objects.

  1. Hardness of kamacite and shock histories of 119 meteorites.

    NASA Technical Reports Server (NTRS)

    Jain, A. V.; Gordon, R. B.; Lipschutz, M. E.

    1972-01-01

    Use of metallographic and X-ray diffraction techniques to study the shock histories of 119 iron and stony-iron meteorites, and measurement of the hardness of kamacite in these specimens and in artificially shocked-unannealed and annealed meteorite specimens. Shock increases kamacite hardness, but complications introduced by other physical and chemical properties of meteorites limit its utility as a shock indicator. About 50% of the meteorites studied show evidence for preterrestrial shock loading to pressures of greater than or equal to 130 kb, and 40% have not been shocked to such high pressures. The remaining meteorites have been heat-altered in such a way that their shock histories cannot be determined explicitly. These results, together with those obtained previously, indicate that the plurality, if not the majority, of all iron and stony-iron meteorites sampled by the earth were shocked to pressures of greater than or equal to 130 kb during preterrestrial collisions between asteroidal-sized objects.

  2. A hard X-ray nanoprobe beamline for nanoscale microscopy

    PubMed Central

    Winarski, Robert P.; Holt, Martin V.; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G. Brian; McNulty, Ian; Maser, Jörg

    2012-01-01

    The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals. PMID:23093770

  3. Probing the evolution and morphology of hard carbon spheres

    SciTech Connect

    Pol, Vilas G.; Wen, Jianguo; Lau, Kah Chun; Callear, Samantha; Bowron, Daniel T.; Lin, Chi-Kai; Deshmukh, Sanket A.; Sankaranarayanan, Subramanian; Curtiss, Larry A.; David, William; Miller, Dean J.; Thackeray, Michael M.

    2014-03-01

    Monodispersed hard carbon spheres can be synthesized quickly and reproducibly by autogenic reactions of hydrocarbon precursors, notably polyethylene (including plastic waste), at high temperature and pressure. The carbon microparticles formed by this reaction have a unique spherical architecture, with a dominant internal nanometer layered motif, and they exhibit diamond-like hardness and electrochemical properties similar to graphite. In the present study, in-situ monitoring by X-ray diffraction along with electron microscopy, Raman spectroscopy, neutron pair-distribution function analysis, and computational modeling has been used to elucidate the morphology and evolution of the carbon spheres that form from the autogenic reaction of polyethylene at high temperature and pressure. A mechanism is proposed on how polyethylene evolves from a linear chain-based material to a layered carbon motif. Heating the spheres to 2400-2800 °C under inert conditions increases their graphitic character, particularly at the surface, which enhances their electrochemical and tribological properties.

  4. Monodisperse hard rods in external potentials.

    PubMed

    Bakhti, Benaoumeur; Karbach, Michael; Maass, Philipp; Müller, Gerhard

    2015-10-01

    We consider linear arrays of cells of volume V(c) populated by monodisperse rods of size σV(c),σ=1,2,..., subject to hardcore exclusion interaction. Each rod experiences a position-dependent external potential. In one application we also examine effects of contact forces between rods. We employ two distinct methods of exact analysis with complementary strengths and different limits of spatial resolution to calculate profiles of pressure and density on mesoscopic and microscopic length scales at thermal equilibrium. One method uses density functionals and the other statistically interacting vacancy particles. The applications worked out include gravity, power-law traps, and hard walls. We identify oscillations in the profiles on a microscopic length scale and show how they are systematically averaged out on a well-defined mesoscopic length scale to establish full consistency between the two approaches. The continuum limit, realized as V(c)→0,σ→∞ at nonzero and finite σV(c), connects our highest-resolution results with known exact results for monodisperse rods in a continuum. We also compare the pressure profiles obtained from density functionals with the average microscopic pressure profiles derived from the pair distribution function.

  5. Diffraction operators in paraxial approach

    NASA Astrophysics Data System (ADS)

    Lasso, William; Navas, Marianela; Añez, Liz; Urdaneta, Romer; Díaz, Leonardo; Torres, César O.

    2014-07-01

    Nowadays, research in the field of science education points to the creation of alternative ways of teaching contents encouraging the development of more elaborate reasoning, where a high degree of abstraction and generalization of scientific knowledge prevails. On that subject, this research shows a didactic alternative proposal for the construction of Fresnel and Fraunhoffer diffraction concepts applying the Fourier transform technique in the study of electromagnetic waves propagation in free space. Curvature transparency and Fourier sphere operators in paraxial approximation are used in order to make the usual laborious mathematical approach easier. The main result shows that the composition of optic metaxial operators results in the discovery of a simpler way out of the standard electromagnetic wave propagation in free space between a transmitter and a receptor separated from a given distance. This allows to state that the didactic proposal shown encourages the construction of Fresnel and Fraunhoffer diffraction concepts in a more effective and easier way than the traditional teaching.

  6. dxtbx: the diffraction experiment toolbox.

    PubMed

    Parkhurst, James M; Brewster, Aaron S; Fuentes-Montero, Luis; Waterman, David G; Hattne, Johan; Ashton, Alun W; Echols, Nathaniel; Evans, Gwyndaf; Sauter, Nicholas K; Winter, Graeme

    2014-08-01

    Data formats for recording X-ray diffraction data continue to evolve rapidly to accommodate new detector technologies developed in response to more intense light sources. Processing the data from single-crystal X-ray diffraction experiments therefore requires the ability to read, and correctly interpret, image data and metadata from a variety of instruments employing different experimental representations. Tools that have previously been developed to address this problem have been limited either by a lack of extensibility or by inconsistent treatment of image metadata. The dxtbx software package provides a consistent interface to both image data and experimental models, while supporting a completely generic user-extensible approach to reading the data files. The library is written in a mixture of C++ and Python and is distributed as part of the cctbx under an open-source licence at http://cctbx.sourceforge.net.

  7. Phase Aberrations in Diffraction Microscopy

    SciTech Connect

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  8. Deterministic Bragg Coherent Diffraction Imaging.

    PubMed

    Pavlov, Konstantin M; Punegov, Vasily I; Morgan, Kaye S; Schmalz, Gerd; Paganin, David M

    2017-04-25

    A deterministic variant of Bragg Coherent Diffraction Imaging is introduced in its kinematical approximation, for X-ray scattering from an imperfect crystal whose imperfections span no more than half of the volume of the crystal. This approach provides a unique analytical reconstruction of the object's structure factor and displacement fields from the 3D diffracted intensity distribution centred around any particular reciprocal lattice vector. The simple closed-form reconstruction algorithm, which requires only one multiplication and one Fourier transformation, is not restricted by assumptions of smallness of the displacement field. The algorithm performs well in simulations incorporating a variety of conditions, including both realistic levels of noise and departures from ideality in the reference (i.e. imperfection-free) part of the crystal.

  9. Anomalous diffraction in hyperbolic materials

    NASA Astrophysics Data System (ADS)

    Alberucci, Alessandro; Jisha, Chandroth P.; Boardman, Allan D.; Assanto, Gaetano

    2016-09-01

    We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, i.e., spatial analog of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.

  10. Perturbation theory in electron diffraction

    NASA Astrophysics Data System (ADS)

    Bakken, L. N.; Marthinsen, K.; Hoeier, R.

    1992-12-01

    The Bloch-wave approach is used for discussing multiple inelastic electron scattering and higher-order perturbation theory in inelastic high-energy electron diffraction. In contrast to previous work, the present work describes three-dimensional diffraction so that higher-order Laue zone (HOLZ) effects are incorporated. Absorption is included and eigenvalues and eigenvectors are calculated from a structure matrix with the inclusion of an absorptive potential. Centrosymmetric as well as non-centrosymmetric crystal structures are allowed. An iteration method with a defined generalized propagation function for solving the inelastic coupling equations is described. It is shown that a similar iteration method with the same propagation function can be used for obtaining higher-order perturbation terms for the wave-function when a perturbation is added to the crystal potential. Finally, perturbation theory by matrix calculations when a general perturbation is added to the structure matrix is considered.

  11. Diffraction moire: The dynamic regime

    SciTech Connect

    Deason, V.A.; Epstein, J.S.; Reuter, W.G.

    1987-01-01

    The technique of diffraction moire interferometry has been applied to numerous static and slowly changing stress configurations. The method has now been extended to the study of dynamic loading events, especially to the interaction of dynamic stress waves with such flaws as cracks or with the variations in composition found in composite materials. A pulsed ruby laser was used to provide the rapid (20 ns wide), brilliant and coherent illumination required for these studies. The technique and several specific applications are described.

  12. Industrial applications of neutron diffraction

    SciTech Connect

    Felcher, G.P.

    1989-01-01

    Neutron diffraction (or, to be more general, neutron scattering) is a most versatile and universal tool, which has been widely employed to probe the structure, the dynamics and the magnetism of condensed matter. Traditionally used for fundamental research in solid state physics, this technique more recently has been applied to problems of immediate industrial interest, as illustrated in examples covering the main fields of endeavour. 14 refs., 14 figs.

  13. Confinement, Turbulence and Diffraction Catastrophes

    NASA Astrophysics Data System (ADS)

    Blaizot, J.-P.; Nowak, M. A.

    2009-08-01

    Many features of the large N transition that occurs in the spectral density of Wilson loops as a function of loop area (observed recently in numerical simulations of Yang-Mills theory by Narayanan and Neuberger) can be captured by a simple Burgers equation used to model turbulence. Spectral shock waves that precede this asymptotic limit exhibit universal scaling with N, with indices that can be related to Berry indices for diffraction catastrophes.

  14. Neutron diffraction and Vitamin E

    NASA Astrophysics Data System (ADS)

    Harroun, T. A.

    2010-11-01

    It is generally accepted that neutron diffraction from model membrane systems is an effective biophysical technique for determining membrane structure. Here we describe an example of how deuterium labelling can elucidate the location of specific membrane soluble molecules, including a brief discussion of the technique itself. We show that deuterium labelled α-tocopherol sits upright in the bilayer, as might be expected, but at very different locations within the bilayer, depending on the degree of lipid chain unsaturation.

  15. Aberrations of diffracted wave fields: distortion.

    PubMed

    Harvey, James E; Bogunovic, Dijana; Krywonos, Andrey

    2003-03-01

    Near-field diffraction patterns are merely aberrated Fraunhofer diffraction patterns. These aberrations, inherent to the diffraction process, provide insight and understanding into wide-angle diffraction phenomena. Nonparaxial patterns of diffracted orders produced by a laser beam passing through a grating and projected upon a plane screen exhibit severe distortion (W311). This distortion is an artifact of the configuration chosen to observe diffraction patterns. Grating behavior expressed in terms of the direction cosines of the propagation vectors of the incident and diffracted orders exhibits no distortion. Use of a simple direction cosine diagram provides an elegant way to deal with nonparaxial diffraction patterns, particularly when large obliquely incident beams produce conical diffraction.

  16. Diffraction Techniques in Structural Biology

    PubMed Central

    Egli, Martin

    2010-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy and neutron diffraction are well established and have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches and high-speed computing and visualization, now provide specialists and non-specialists alike with a steady flow of molecular images of unprecedented detail. The present chapter combines a general overview of diffraction methods with a step-by-step description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  17. Diffraction Techniques in Structural Biology

    PubMed Central

    Egli, Martin

    2016-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:27248784

  18. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of Rv2827c from Mycobacterium tuberculosis

    SciTech Connect

    Janowski, Robert

    2006-08-01

    M. tuberculosis hypothetical protein Rv2827c was cloned, expressed, purified and crystallized. Preliminary X-ray diffraction data were collected to a resolution of 1.93 Å. The hypothetical protein Rv2827c from Mycobacterium tuberculosis was cloned and heterologously expressed in Escherichia coli. It was purified using affinity and size-exclusion chromatographic techniques and then crystallized. Preliminary X-ray diffraction data analysis suggests the presence of two translationally related molecules in the asymmetric unit of the orthorhombic crystals.

  19. Hard Work and Hard Data: Getting Our Message Out.

    ERIC Educational Resources Information Center

    Glau, Gregory R.

    Unless questions about student performance and student retention can be answered and unless educators are proactive in finding and publicizing such information, basic writing programs cannot determine if what they are doing is working. Hard data, especially from underrepresented groups, is needed to support these programs. At Arizona State…

  20. De-icing: recovery of diffraction intensities in the presence of ice rings

    SciTech Connect

    Chapman, Michael S.; Somasundaram, Thayumanasamy

    2010-06-01

    Correction for ice-rings in diffraction images is demonstrated as an alternative to exclusion of affected reflections. Completeness can be increased without significant loss of quality in the integrated data. Macromolecular structures are routinely determined at cryotemperatures using samples flash-cooled in the presence of cryoprotectants. However, sometimes the best diffraction is obtained under conditions where ice formation is not completely ablated, with the result that characteristic ice rings are superimposed on the macromolecular diffraction. In data processing, the reflections that are most affected by the ice rings are usually excluded. Here, an alternative approach of subtracting the ice diffraction is tested. High completeness can be retained with little adverse effect upon the quality of the integrated data. This offers an alternate strategy when high levels of cryoprotectant lead to loss of crystal quality.

  1. Magnetic levitation for hard superconductors

    SciTech Connect

    Kordyuk, A.A.

    1998-01-01

    An approach for calculating the interaction between a hard superconductor and a permanent magnet in the field-cooled case is proposed. The exact solutions were obtained for the point magnetic dipole over a flat ideally hard superconductor. We have shown that such an approach is adaptable to a wide practical range of melt-textured high-temperature superconductors{close_quote} systems with magnetic levitation. In this case, the energy losses can be calculated from the alternating magnetic field distribution on the superconducting sample surface. {copyright} {ital 1998 American Institute of Physics.}

  2. Future hard disk drive systems

    NASA Astrophysics Data System (ADS)

    Wood, Roger

    2009-03-01

    This paper briefly reviews the evolution of today's hard disk drive with the additional intention of orienting the reader to the overall mechanical and electrical architecture. The modern hard disk drive is a miracle of storage capacity and function together with remarkable economy of design. This paper presents a personal view of future customer requirements and the anticipated design evolution of the components. There are critical decisions and great challenges ahead for the key technologies of heads, media, head-disk interface, mechanics, and electronics.

  3. Triple Bragg diffraction in paratellurite crystal

    NASA Astrophysics Data System (ADS)

    Kotov, V. M.; Averin, S. V.; Voronko, A. I.; Kotov, E. V.; Tikhomirov, S. A.

    2017-07-01

    Triple Bragg diffraction in a paratellurite crystal has been considered for the case when the plane of diffraction is oblique to the optical axis of the crystal. It has been shown that effective photoelastic constants for isotropic and anisotropic diffraction depend on the inclination of the plane of diffraction insignificantly. Triple Bragg diffraction of 0.63-μm coherent radiation in paratellurite at a 47.3-MHz slow acoustic wave has been experimentally demonstrated. For an optical power of 0.69 W delivered to a piezoconverter, the relative intensities of diffraction orders equal 0.4, 0.4, 0.1, and 0.1, respectively.

  4. 48 CFR 37.202 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACTING SERVICE CONTRACTING Advisory and Assistance Services 37.202 Exclusions. The following activities...) Routine information technology services unless they are an integral part of a contract for the acquisition... research involving medical, biological, physical, social, psychological, or other phenomena....

  5. 48 CFR 37.502 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 37.502 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING SERVICE CONTRACTING Management Oversight of Service Contracts 37.502 Exclusions. (a) This subpart... subpart. However, good management practices and contract administration techniques should be used...

  6. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This subpart... award to— (1) Federal Prison Industries, Inc. (see subpart 8.6); or (2) Javits-Wagner-O'Day Act...

  7. 48 CFR 19.1504 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... PROGRAMS SMALL BUSINESS PROGRAMS Women-Owned Small Business (WOSB) Program 19.1504 Exclusions. This subpart... award to— (1) Federal Prison Industries, Inc. (see subpart 8.6); or (2) Javits-Wagner-O'Day Act...

  8. Teaching With Documents: Chinese Exclusion Forms.

    ERIC Educational Resources Information Center

    Simmons, Linda, Ed.

    1986-01-01

    Reviews the history of Chinese immigration to the United States and provides a facsimilie of a form used to document immigrants under the Chinese Exclusion Act. Teaching suggestions are included. (JDH)

  9. Exclusion of pneumothorax by radionuclide lung scan

    SciTech Connect

    Weiss, P.E.

    1986-05-01

    A case is reported in which ventilation lung imaging was useful in excluding a large pneumothorax. This technique may be helpful in patients with emphysema in whom exclusion of pneumothorax by radiographic criteria might be difficult.

  10. Central exclusive production and the Durham model

    NASA Astrophysics Data System (ADS)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.

    2014-11-01

    We review some selected results within the Durham model of central exclusive production. We discuss the theoretical aspects of this approach and consider the phenomenological implications for a selection of processes.

  11. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SMALL ONSHORE STORAGE FACILITIES Oil Storage Facilities § 113.5 Exclusions. This subpart does not apply to: (a) Those facilities whose average daily oil throughout is more than their fixed oil...

  12. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SMALL ONSHORE STORAGE FACILITIES Oil Storage Facilities § 113.5 Exclusions. This subpart does not apply to: (a) Those facilities whose average daily oil throughout is more than their fixed oil...

  13. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SMALL ONSHORE STORAGE FACILITIES Oil Storage Facilities § 113.5 Exclusions. This subpart does not apply to: (a) Those facilities whose average daily oil throughout is more than their fixed oil...

  14. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SMALL ONSHORE STORAGE FACILITIES Oil Storage Facilities § 113.5 Exclusions. This subpart does not apply to: (a) Those facilities whose average daily oil throughout is more than their fixed oil...

  15. 40 CFR 113.5 - Exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SMALL ONSHORE STORAGE FACILITIES Oil Storage Facilities § 113.5 Exclusions. This subpart does not apply to: (a) Those facilities whose average daily oil throughout is more than their fixed oil...

  16. 32 CFR 989.13 - Categorical exclusion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.13 Categorical exclusion. (a) CATEXs define those categories... environment and do not, therefore, require further environmental analysis in an EA or an EIS. The list of...

  17. Deep Inelastic Exclusive $\\rho^0$ Production using 485-GeV Muons

    SciTech Connect

    Schmitt, Michael Henry

    1992-01-01

    Neutral vector mesons share the quantum numbers as the photon, consequently, they are produced copiously in diffractive interactions of photons. The lightest of these, the $p^0$ meson, have been studied in the absorption of high energy virtual photons on hydrogen and deuterium. The mass spectrum, decay distribution, and momentum transfer to the target nucleon has been studied as a function of the kinematic variables. The interference of the two-pion resonance and continuum is constant as a function of the virtual photon mass, $Q^2$ • The $p^0$ polarization changes from purely transverse at low $Q^2$ to predominantly longitudinal at high $Q^2$. The azimuthal decay distribution conforms to the expected form, including terms for transverse-transverse and transverse-longitudinal interference. The diffractive slope parameter declines only slightly with $Q^2$ , indicating that for $Q^2$ up to approximately 4 Ge$V^2$ , production of exclusive p0 mesons is_ a diffractive process .

  18. Hard Facts and Soft Skills

    ERIC Educational Resources Information Center

    Terego, Alex

    2009-01-01

    The argument now raging in academic circles pits those who espouse teaching 21st century skills against those who believe that schools should be teaching explicit and well-sequenced content. This debate has largely been framed as an either-or proposition. In this author's view, portraying this debate as one between two mutually exclusive sides…

  19. Dynamic indentation hardness of materials

    NASA Astrophysics Data System (ADS)

    Koeppel, Brian James

    Indentation hardness is one of the simplest and most commonly used measures for quickly characterizing material response under static loads. Hardness may mean resistance to cutting to a machinist, resistance to wear to a tribologist, or a measure of flow stress to a design engineer. In this simple technique, a predetermined force is applied to an indenter for 5-30 seconds causing it to penetrate a specimen. By measuring the load and the indentation size, a hardness value is determined. However, the rate of deformation during indenter penetration is of the order of 10sp{-4}\\ ssp{-1}. In most practical applications, such as high speed machining or impact, material deforms at strain rates in excess of 10sp3{-}10sp5\\ ssp{-1}. At such high rates, it is well established that the plastic behavior of materials is considerably different from their static counterpart. For example, materials exhibit an increase in their yield stress, flow stress, fracture stress, and fracture toughness at high strain rates. Hence, the use of static hardness as an indicator of material response under dynamic loads may not be appropriate. Accordingly, a simple dynamic indentation hardness tester is developed for characterizing materials at strain rates similar to those encountered in realistic situations. The experimental technique uses elastic stress wave propagation phenomena in a slender rod. The technique is designed to deliver a single indentation load of 100-200 mus duration. Similar to static measurements, the dynamic hardness is determined from the measured load and indentation size. Hardness measurements on a range of metals have revealed that the dynamic hardness is consistently greater than the static hardness. The increase in hardness is strongly dependent on the crystal structure of the material. The observed trends in hardness are also found to be consistent with the yield and flow stresses of these materials under uniaxial compression. Therefore, it is suggested that the

  20. 42 CFR 1001.1901 - Scope and effect of exclusion.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Scope and effect of exclusion. 1001.1901 Section... SERVICES OIG AUTHORITIES PROGRAM INTEGRITY-MEDICARE AND STATE HEALTH CARE PROGRAMS Waivers and Effect of Exclusion § 1001.1901 Scope and effect of exclusion. (a) Scope of exclusion. Exclusions of individuals...

  1. The Cost Effectiveness of LAA Exclusion.

    PubMed

    Kreidieh, Bahij; Mañero, Moisés Rodríguez; Cortez, Sergio H Ibarra; Schurmann, Paul; Valderrábano, Miguel

    2016-01-01

    Left atrial appendage (LAA) exclusion strategies are increasingly utilized for stroke prevention in lieu of oral anticoagulants. Reductions in bleeding risk and long-term compliance issues bundled with comparable stroke prevention benefits have made these interventions increasingly attractive. Unfortunately, healthcare funding remains limited. Comparative cost economic analyses are therefore critical in optimizing resource allocation. In this review we seek to discourse the cost economics analysis of LAA exclusion over available therapeutic alternatives (warfarin and the new oral anticoagulants (NOACs)). .

  2. History of the Combat Zone Tax Exclusion

    DTIC Science & Technology

    2011-09-01

    married members) exemption that precisely offset a contemporaneous cut in the personal deduction. Unlike its WWI predecessor, the 1942 exclusion was not...tax benefits with regard to Cold War conflicts. In the Korean War, these goals were achieved with a timely extension and termination of the combat...captured, or missing in Cambodia , though eligible for income tax exclusions by virtue of their formal deployment location, were ineligible for v

  3. Exclusive Reactions Involving Pions and Nucleons

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Blattnig, Steve R.; Tripathi, R. K.

    2002-01-01

    The HZETRN code requires inclusive cross sections as input. One of the methods used to calculate these cross sections requires knowledge of all exclusive processes contributing to the inclusive reaction. Conservation laws are used to determine all possible exclusive reactions involving strong interactions between pions and nucleons. Inclusive particle masses are subsequently determined and are needed in cross-section calculations for inclusive pion production.

  4. Small angle detectors for study diffractive processes with CMS

    NASA Astrophysics Data System (ADS)

    Albrow, M.; Bell, A. J.; Enterria, D. d.; Hall-Wilton, R.; Los, S.; Mokhov, N.; Murray, M.; Penzo, A.; Popescu, S.; Ronzhin, A.; Samoylenko, V. D.; Sobol, A.; Veres, G.

    2014-10-01

    The approach and detectors for diffractive physics based on two current projects—Forward Shower Counter (FSC) and Proton Precision Spectrometer (PPS) are presented. FSC system consists of six (3+3) Stations of scintillator counters, which surround closely the beam pipes along 59 m < |z| < 140 m from IP5 on both plus (+) and minus (-) sides. These will detect showers from very forward particles with rapidity 7.5 < |η| < 10 interacting in the beam pipe and surrounding material. FSC allow measurements of single diffraction: p+p → p+G+X (where G is rapidity gap) for lower masses and double diffraction p+p → X+G+X with a large central rapidity gap. The counters can also be used for beam real-time monitoring and will make an invaluable contribution to the understanding of the background environment and its topology. PPS is designed for study the central exclusive production pp → p+X+p, where the + signs denote the absence of hadronic activity (that is, the presence of a rapidity gap) between the outgoing protons and the decay products of the central system X. The precise measurement of the kinematical parameters of the outgoing protons enables to study the properties of the central state X. In PPS part we consider the detector for high precision timing of these protons—QUARTIC. It consists of L-shape bars with quartz or sapphire radiator. The time resolution of the QUARTIC prototypes achieved ≈ 10 ps.

  5. Estimate of the single diffractive heavy quark production in heavy ion collisions at the CERN LHC

    SciTech Connect

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T.

    2010-03-01

    The single diffractive cross section for heavy quarks production is calculated at next-to-leading order (for nucleus-nucleus collisions. Such processes are expected to occur at the LHC, where the nuclei involved are lead at {radical}(s)=5.5 TeV and calcium at {radical}(s)=6.3 TeV. We start using the hard diffractive factorization formalism, taking into account a recent experimental parametrization for the Pomeron structure function (DPDF). Absorptive corrections are accounted for by the multiple Pomeron contributions considering a gap survival probability, where its theoretical uncertainty for nuclear collisions is discussed. We estimate the diffractive ratios for the single diffraction process in nuclear coherent/incoherent collisions at the LHC.

  6. Focusing and spectral characteristics of periodic diffractive optical elements with circular symmetry under femtosecond pulsed illumination.

    PubMed

    Mendoza-Yero, Omel; Mínguez-Vega, Gladys; Lancis, Jesús; Climent, Vicent

    2007-11-01

    The analytical solution is derived, within the Rayleigh-Sommerfeld formulation of diffraction, for the on-axis spectral irradiance of a broadband source after diffracting through a circular symmetric hard aperture. By using this solution, and within the paraxial approximation, we investigate several diffraction-induced effects originated by binary diffractive optical elements made up of a set of annular apertures with equal areas and periodic in the squared radial coordinate. In particular, the ability to focus femtosecond pulses is investigated. In addition, the analysis of the spectral modifier function associated with these elements allows us to simulate spectral shifts at focus positions. Finally, we introduce a relatively simple and low-cost technique to slice the spectrum of a broadband source in order to generate narrow bands or wavelength channels.

  7. Accessing proton generalized parton distributions and pion distribution amplitudes with the exclusive pion-induced Drell-Yan process at J-PARC

    NASA Astrophysics Data System (ADS)

    Sawada, Takahiro; Chang, Wen-Chen; Kumano, Shunzo; Peng, Jen-Chieh; Sawada, Shinya; Tanaka, Kazuhiro

    2016-06-01

    Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply virtual Compton scattering and deeply virtual meson production with lepton beam. A complementary probe with hadron beam is the exclusive pion-induced Drell-Yan process. In this paper, we discuss recent theoretical advances on describing this process in terms of nucleon GPDs and pion distribution amplitudes. Furthermore, we address the feasibility of measuring the exclusive pion-induced Drell-Yan process π-p →μ+μ-n via a spectrometer at the High Momentum Beamline being constructed at J-PARC in Japan. Realization of such measurement at J-PARC will provide a new test of perturbative QCD descriptions of a novel class of hard exclusive reactions. It will also offer the possibility of experimentally accessing nucleon GPDs at large timelike virtuality.

  8. Hard Trying and These Recipes

    ERIC Educational Resources Information Center

    Atwell, Nancie

    2003-01-01

    Writers thrive when they are motivated to work hard, have regular opportunities to practice and reflect, and benefit from a knowledgeable teacher who knows writing. Student feedback to lessons during writing workshop helped guide Nancie Atwell in her quest to provide the richest and most efficient path to better writing.

  9. Playing the Numbers: Hard Choices

    ERIC Educational Resources Information Center

    Doyle, William R.

    2009-01-01

    Stateline.org recently called this recession the worst in 50 years for state budgets. As has been the case in past economic downturns, higher education looks to be particularly hard hit. Funds from the American Recovery and Relief Act may have postponed some of the difficulty for many colleges and universities, but the outlook for public higher…

  10. Metrics for Hard Goods Merchandising.

    ERIC Educational Resources Information Center

    Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

    Designed to meet the job-related metric measurement needs of students interested in hard goods merchandising, this instructional package is one of five for the marketing and distribution cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know the occupational…

  11. Hard Knocks in Tyrrhena Terra

    NASA Image and Video Library

    2017-02-02

    NASA Mars Reconnaissance Orbiter observed a small portion of a dark crater floor in the Tyrrhena Terra region of Mars. This is largely ancient hard bedrock that has been cratered by numerous impacts over the eons. http://photojournal.jpl.nasa.gov/catalog/PIA11179

  12. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  13. Erythrocyte shape analysis by means of laser diffraction

    NASA Astrophysics Data System (ADS)

    Bayer, Rainer; Schauf, Burkhard; Guenther, Bernd

    1992-05-01

    In quite a large number of disorders, reduced flexibility of red blood cells (RBC) can be detected. In cardiovascular diseases it is supposed that rigidification of RBC may be regarded as a pathogenetic factor aggravating ischemia by disturbing capillary perfusion. Most methods established so far to estimate RBC deformability are hard to standardize and include large measurement errors. We present a low-cost system to determine RBC shape and flexibility. It combines laser diffraction of RBC in Couette flow with automated computer assisted image analysis. Effortless handling allows the system to be used for RBC elongation measurements even in routine diagnostics. Analysis of the whole information content of diffraction patterns reduces errors due to noisy diffraction patterns of working a little off axis. The system allows detection of very small changes in flexibility (less than 5%). The accuracy of measurement is not affected by variation of hematocrit or the intensity of transmitted light. Using the newly developed system it is demonstrated (1) that mechanically induced RBC rigidification may occur without hemolysis; (2) that in photodynamic therapy (e.g., pheophorbide A) RBC rigidification occurs during irridation; and (3) that in-vitro aging of conserved blood may partly be inhibited by calmodulin antagonists (e.g., fendiline).

  14. Investigation Of Far-Field Diffraction

    NASA Technical Reports Server (NTRS)

    Wang, Yaujen; Scholl, Marija S.

    1993-01-01

    Report describes experimental investigation of far-field diffracton by normally illuminated circular apertures with diameters of several wavelengths of incident light. Purpose of investigation to determine whether Keller's "geometrical" theory of diffraction valid for diffraction phenomena of this kind.

  15. Crystallography: Resolution beyond the diffraction limit

    NASA Astrophysics Data System (ADS)

    Shen, Jian-Ren

    2016-02-01

    A method has been devised that extends the resolution of X-ray crystal structures beyond the diffraction limit. This might help to improve the visualization of structures of proteins that form 'poorly diffracting' crystals. See Letter p.202

  16. Diffractive optics: Design, fabrication, and applications

    NASA Technical Reports Server (NTRS)

    Morris, G. Michael

    1993-01-01

    The topics are presented in viewgraph form and include the following: features, applications, surface relief diffractive optics, optical data storage, waveguide lenses, diffractive lense imaging, phase grating synthesis, sub-wavelength structured surfaces, etc.

  17. Coherent Diffractive Imaging at LCLS

    NASA Astrophysics Data System (ADS)

    Schulz, Joachim

    2010-03-01

    Soft x-ray FEL light sources produce ultrafast x-ray pulses with outstanding high peak brilliance. This might enable the structure determination of proteins that cannot be crystallized. The deposited energy would destroy the molecules completely, but owing to the short pulses the destruction will ideally only happen after the termination of the pulse. In order to address the many challenges that we face in attempting molecular diffraction, we have carried out experiments in coherent diffraction from protein nanocrystals at the Linac Coherent Light Source (LCLS) at SLAC. The periodicity of these objects gives us much higher scattering signals than uncrystallized proteins would. The crystals are filtered to sizes less than 2 micron, and delivered to the pulsed X-ray beam in a liquid jet. The effects of pulse duration and fluence on the high-resolution structure of the crystals have been studied. Diffraction patterns are recorded at a repetition rate of 30 Hz with pnCCD detectors. This allows us to take 108,000 images per hour. With 2-mega-pixel-detectors this gives a data-rate of more than 400 GB per hour. The automated sorting and evaluation of hundreds of thousands images is another challenge of this kind of experiments. Preliminary results will be presented on our first LCLS experiments. This work was carried out as part of a collaboration, for which Henry Chapman is the spokesperson. The collaboration consists of CFEL DESY, Arizona State University, SLAC, Uppsala University, LLNL, The University of Melbourne, LBNL, the Max Planck Institute for Medical Research, and the Max Planck Advanced Study Group (ASG) at the CFEL. The experiments were carried out using the CAMP apparatus, which was designed and built by the Max Planck ASG at CFEL. The LCLS is operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

  18. 50 years of fiber diffraction.

    PubMed

    Holmes, Kenneth C

    2010-05-01

    In 1955 Ken Holmes started working on tobacco mosaic virus (TMV) as a research student with Rosalind Franklin at Birkbeck College, London. Afterward he spent 18months as a post doc with Don Caspar and Carolyn Cohen at the Children's Hospital, Boston where he continued the work on TMV and also showed that the core of the thick filament of byssus retractor muscle from mussels is made of two-stranded alpha-helical coiled-coils. Returning to England he joined Aaron Klug's group at the newly founded Laboratory of Molecular Biology in Cambridge. Besides continuing the TMV studies, which were aimed at calculating the three-dimensional density map of the virus, he collaborated with Pringle's group in Oxford to show that two conformation of the myosin cross-bridge could be identified in insect flight muscle. In 1968 he opened the biophysics department at the Max Planck Institute for Medical Research in Heidelberg, Germany. With Gerd Rosenbaum he initiated the use of synchrotron radiation as a source for X-ray diffraction. In his lab the TMV structure was pushed to 4A resolution and showed how the RNA binds to the protein. With his co-workers he solved the structure of g-actin as a crystalline complex and then solved the structure of the f-actin filament by orientating the g-actin structure so as to give the f-actin fiber diffraction pattern. He was also able to solve the structure of the complex of actin with tropomyosin from fiber diffraction.

  19. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  20. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason--and in fact its original trigger--is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, the authors discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behavior it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time to work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERN in Geneva and in July 1994 at LBL in Berkeley. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  1. Issues in Optical Diffraction Theory

    PubMed Central

    Mielenz, Klaus D.

    2009-01-01

    This paper focuses on unresolved or poorly documented issues pertaining to Fresnel’s scalar diffraction theory and its modifications. In Sec. 2 it is pointed out that all thermal sources used in practice are finite in size and errors can result from insufficient coherence of the optical field. A quarter-wave criterion is applied to show how such errors can be avoided by placing the source at a large distance from the aperture plane, and it is found that in many cases it may be necessary to use collimated light as on the source side of a Fraunhofer experiment. If these precautions are not taken the theory of partial coherence may have to be used for the computations. In Sec. 3 it is recalled that for near-zone computations the Kirchhoff or Rayleigh-Sommerfeld integrals are applicable, but fail to correctly describe the energy flux across the aperture plane because they are not continuously differentiable with respect to the assumed geometrical field on the source side. This is remedied by formulating an improved theory in which the field on either side of a semi-reflecting screen is expressed as the superposition of mutually incoherent components which propagate in the opposite directions of the incident and reflected light. These components are defined as linear combinations of the Rayleigh-Sommerfeld integrals, so that they are rigorous solutions of the wave equation as well as continuously differentiable in the aperture plane. Algorithms for using the new theory for computing the diffraction patterns of circular apertures and slits at arbitrary distances z from either side of the aperture (down to z = ± 0.0003 λ) are presented, and numerical examples of the results are given. These results show that the incident geometrical field is modulated by diffraction before it reaches the aperture plane while the reflected field is spilled into the dark space. At distances from the aperture which are large compared to the wavelength λ these field expressions are

  2. Issues in Optical Diffraction Theory.

    PubMed

    Mielenz, Klaus D

    2009-01-01

    This paper focuses on unresolved or poorly documented issues pertaining to Fresnel's scalar diffraction theory and its modifications. In Sec. 2 it is pointed out that all thermal sources used in practice are finite in size and errors can result from insufficient coherence of the optical field. A quarter-wave criterion is applied to show how such errors can be avoided by placing the source at a large distance from the aperture plane, and it is found that in many cases it may be necessary to use collimated light as on the source side of a Fraunhofer experiment. If these precautions are not taken the theory of partial coherence may have to be used for the computations. In Sec. 3 it is recalled that for near-zone computations the Kirchhoff or Rayleigh-Sommerfeld integrals are applicable, but fail to correctly describe the energy flux across the aperture plane because they are not continuously differentiable with respect to the assumed geometrical field on the source side. This is remedied by formulating an improved theory in which the field on either side of a semi-reflecting screen is expressed as the superposition of mutually incoherent components which propagate in the opposite directions of the incident and reflected light. These components are defined as linear combinations of the Rayleigh-Sommerfeld integrals, so that they are rigorous solutions of the wave equation as well as continuously differentiable in the aperture plane. Algorithms for using the new theory for computing the diffraction patterns of circular apertures and slits at arbitrary distances z from either side of the aperture (down to z = ± 0.0003 λ) are presented, and numerical examples of the results are given. These results show that the incident geometrical field is modulated by diffraction before it reaches the aperture plane while the reflected field is spilled into the dark space. At distances from the aperture which are large compared to the wavelength λ these field expressions are reduced

  3. Coherent x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Pitney, John Allen

    Conventional x-ray diffraction has historically been done under conditions such that the measured signal consists of an incoherent addition of scattering which is coherent only on a length scale determined by the properties of the beam. The result of the incoherent summation is a statistical averaging over the whole illuminated volume of the sample, which yields certain kinds of information with a high degree of precision and has been key to the success of x-ray diffraction in a variety of applications. Coherent x-ray scattering techniques, such as coherent x-ray diffraction (CXD) and x-ray intensity fluctuation spectroscopy (XIFS), attempt to reduce or eliminate any incoherent averaging so that specific, local structures couple to the measurement without being averaged out. In the case of XIFS, the result is analogous to dynamical light scattering, but with sensitivity to length scales less than 200 nm and time scales from 10-3 s to 103 s. When combined with phase retrieval, CXD represents an imaging technique with the penetration, in situ capabilities, and contrast mechanisms associated with x-rays and with a spatial resolution ultimately limited by the x-ray wavelength. In practice, however, the spatial resolution of CXD imaging is limited by exposure to about 100 A. This thesis describes CXD measurements of the binary alloy Cu3Au and the adaptation of phase retrieval methods for the reconstruction of real-space images of Cu3Au antiphase domains. The theoretical foundations of CXD are described in Chapter 1 as derived from the kinematical formulation for x-ray diffraction and from the temporal and spatial coherence of radiation. The antiphase domain structure of Cu 3Au is described, along with the associated reciprocal-space structure which is measured by CXD. CXD measurements place relatively stringent requirements on the coherence properties of the beam and on the detection mechanism of the experiment; these requirements and the means by which they have been

  4. Fiber optic diffraction grating maker

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  5. Fiber optic diffraction grating maker

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  6. DIFFRACTION DISSOCIATION - 50 YEARS LATER.

    SciTech Connect

    WHITE, S.N.

    2005-04-27

    The field of Diffraction Dissociation, which is the subject of this workshop, began 50 years ago with the analysis of deuteron stripping in low energy collisions with nuclei. We return to the subject in a modern context- deuteron dissociation in {radical}s{sub NN} = 200 GeV d-Au collisions recorded during the 2003 RHIC run in the PHENIX experiment. At RHIC energy, d {yields} n+p proceeds predominantly (90%) through Electromagnetic Dissociation and the remaining fraction via the hadronic shadowing described by Glauber. Since the dissociation cross section has a small theoretical error we adopt this process to normalize other cross sections measured in RHIC.

  7. Details on Exclusive Use Data Protection for Minor Use Registrations

    EPA Pesticide Factsheets

    This document provides information about issues related to exclusive use data protection for minor use registrations, including extension of the exclusive use period and establishing a new exclusive use period.

  8. 5 CFR 919.1020 - Voluntary exclusion or voluntarily excluded.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 919.1020 Voluntary exclusion or voluntarily excluded. (a) Voluntary exclusion means a person's.... Voluntary exclusion must have governmentwide effect. (b) Voluntarily excluded means the status of a...

  9. Undergraduate Experiment with Fractal Diffraction Gratings

    ERIC Educational Resources Information Center

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  10. Undergraduate Experiment with Fractal Diffraction Gratings

    ERIC Educational Resources Information Center

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  11. Ultrafast electron diffraction from aligned molecules

    SciTech Connect

    Centurion, Martin

    2015-08-17

    The aim of this project was to record time-resolved electron diffraction patterns of aligned molecules and to reconstruct the 3D molecular structure. The molecules are aligned non-adiabatically using a femtosecond laser pulse. A femtosecond electron pulse then records a diffraction pattern while the molecules are aligned. The diffraction patterns are then be processed to obtain the molecular structure.

  12. Teenage pregnancy and exclusive breastfeeding rates.

    PubMed

    Puapompong, Pawin; Raungrongmorakot, Kasem; Manolerdtewan, Wichian; Ketsuwan, Sukwadee; Wongin, Sinutchanan

    2014-09-01

    Teenage pregnancy is an important health issue globally and in Thailand Younger age mothers decide on the breastfeeding practices ofthe first 6-month. To find the rates of 6-month exclusive breastfeeding practices of teenage mothers and compare them with the rates of 6-month exclusive breastfeeding practices in mothers who are 20 years of age or more. Three thousand five hundred sixty three normal, postpartum women, who delivered without complications at the HRH Princess Maha Chakri Sirindhorn Medical Center in the Nakhon Nayok Province between 2010 and2013 were included in this study. At the second daypostpartum, the data of latch scores and the data of the practice of exclusive breastfeeding were collected Telephone follow-ups on the seventh, fourteenth, and forty-fifth postpartum days and at the second, fourth, and sixth month postpartum month were collected and used for exclusive breastfeeding data following discharge. Demographic data included the maternal age, parity, gestational age, marital status, occupation, religion, route ofdelivery, estimated blood loss, body mass index, nipple length, and the childs birth weight. The collected data was analyzed by the t-test, Chi-square, and odds ratio with 95% confidence interval. The percentage of teenage pregnancies was at 14.8% (527 cases). On postpartum day 2, the percentage of latch scores of 8 or less was 66.4%. At the seventh, fourteenth, and forty-fifth day and at the second, fourth, and sixth months postpartum, the exclusive breastfeeding rates were 88.5, 78.5, 57.6, 43.1, 32.9, and27.0%, respectively. Comparison of the 6-month exclusive breastfeeding rates between teenage mothers and mothers 20 years ofage or older were not statistically significant (p<0.05). The 6-month exclusive breastfeeding rate of teenage mothers was at 27.0% and had no significant differences from the rates of mothers 20 years of age or more.

  13. Improved self-exclusion program: preliminary results.

    PubMed

    Tremblay, Nicole; Boutin, Claude; Ladouceur, Robert

    2008-12-01

    The gambling industry has offered self-exclusion programs for quite a long time. Such measures are designed to limit access to gaming opportunities and provide problem gamblers with the help they need to cease or limit their gambling behaviour. However, few studies have empirically evaluated these programs. This study has three objectives: (1) to observe the participation in an improved self-exclusion program that includes an initial voluntary evaluation, phone support, and a mandatory meeting, (2) to evaluate satisfaction and usefulness of this service as perceived by self-excluders, (3) to measure the preliminary impact of this improved program. One hundred sixteen self-excluders completed a questionnaire about their satisfaction and their perception of the usefulness during the mandatory meeting. Among those participants, 39 attended an initial meeting. Comparisons between data collected at the initial meeting and data taken at the final meeting were made for those 39 participants. Data showed that gamblers chose the improved self-exclusion program 75% of the time; 25% preferred to sign a regular self-exclusion contract. Among those who chose the improved service, 40% wanted an initial voluntary evaluation and 37% of these individuals actually attended that meeting. Seventy percent of gamblers came to the mandatory meeting, which was a required condition to end their self-exclusion. The majority of participants were satisfied with the improved self-exclusion service and perceived it as useful. Major improvements were observed between the final and the initial evaluation on time and money spent, consequences of gambling, DSM-IV score, and psychological distress. The applicability of an improved self-exclusion program is discussed and, as shown in our study, the inclusion of a final mandatory meeting might not be so repulsive for self-excluders. Future research directives are also proposed.

  14. Diffractive molecular-orbital tomography

    NASA Astrophysics Data System (ADS)

    Zhai, Chunyang; Zhu, Xiaosong; Lan, Pengfei; Wang, Feng; He, Lixin; Shi, Wenjing; Li, Yang; Li, Min; Zhang, Qingbin; Lu, Peixiang

    2017-03-01

    High-order-harmonic generation in the interaction of femtosecond lasers with atoms and molecules opens the path to molecular-orbital tomography and to probe the electronic dynamics with attosecond-Ångström resolutions. Molecular-orbital tomography requires both the amplitude and phase of the high-order harmonics. Yet the measurement of phases requires sophisticated techniques and represents formidable challenges at present. Here we report a scheme, called diffractive molecular-orbital tomography, to retrieve the molecular orbital solely from the amplitude of high-order harmonics without measuring any phase information. We have applied this method to image the molecular orbitals of N2, CO2, and C2H2 . The retrieved orbital is further improved by taking account the correction of Coulomb potential. The diffractive molecular-orbital tomography scheme, removing the roadblock of phase measurement, significantly simplifies the molecular-orbital tomography procedure and paves an efficient and robust way to the imaging of more complex molecules.

  15. Flatland optics. III. Achromatic diffraction.

    PubMed

    Lohmann, A W; Pe'er, A; Wang, D; Friesem, A A

    2001-09-01

    In the previous two sections of "Flatland optics" [J. Opt. Soc. Am. A 17, 1755 (2000); 18, 1056 (2001)] we described the basic principles of two-dimensional (2D) optics and showed that a wavelength lambda in three-dimensional (3D) space (x, y, z) may appear in Flatland (x, z) as a wave with another wavelength Lambda=lambda/cos alpha. The tilt angle alpha can be modified by a 3D-Spaceland individual, who then is able to influence the 2D optics in a way that must appear to be magical to 2D-Flatland individuals-in the spirit of E. A. Abbott's science fiction story of 1884 [Flatland, a Romance of Many Dimensions, 6th ed. (Dover, New York, 1952)]. Here we show how the light from a white source can be perceived in Flatland as perfectly monochromatic, so diffraction with white light will be free of color blurring and the contrast of interference fringes can be 100%. The basic considerations for perfectly achromatic diffraction are presented, along with experimental illustration of Talbot self-imaging performed with broadband illumination.

  16. Diffraction optics for terahertz waves

    NASA Astrophysics Data System (ADS)

    Wiltse, James C.

    2004-09-01

    Conventional lenses are important components for many terahertz applications, but ordinary lenses are very difficult to fabricate for short-focal lengths. Multi-level phase-corrected zoned lens antennas have been investigated with particular application at terahertz wavelengths. These zoned lenses (or diffractive optics) give better performance than ordinary lenses, and because of their planar construction are easier and cheaper to fabricate. The depths of cut needed for a grooved zone plate are quite small, even when materials with low dielectric constants are used. Zoned lenses have been built and tested at various frequencies from 100 GHz to 1.5 THz, with phase correction levels of half-wave, quarter-wave, or eighth-wavelength. The inherent losses in transparent materials increase monotonically over this frequency range. Typical low-loss materials include polystyrene, polyethylene, Teflon, polycarbonate, polystyrene foam, foamed polyethylene, low density polytetrafluoroethylene (PTFE), TPX, quartz, sapphire, and silicon. Low dielectric-constant materials are normally preferred to reduce reflection and attenuation losses. Techniques for cutting or milling the materials to small dimensions are important, because at 1.0 THz an eighth-wavelength correction for silicon is only 15 μm. Another characteristic of zoned diffraction optics is their frequency behavior. Previous investigations have considered their bandwidth dependence and quasi-periodic extended frequency response for a specified focal length. As frequency changes, the focal point moves along the axis of the zoned lens. An analysis is given to explain this effect.

  17. Spectral partitioning in diffraction tomography

    SciTech Connect

    Lehman, S K; Chambers, D H; Candy, J V

    1999-06-14

    The scattering mechanism of diffraction tomography is described by the integral form of the Helmholtz equation. The goal of diffraction tomography is to invert this equation in order to reconstruct the object function from the measured scattered fields. During the forward propagation process, the spatial spectrum of the object under investigation is ''smeared,'' by a convolution in the spectral domain, across the propagating and evanescent regions of the received field. Hence, care must be taken in performing the reconstruction, as the object's spectral information has been moved into regions where it may be considered to be noise rather than useful information. This will reduce the quality and resolution of the reconstruction. We show haw the object's spectrum can be partitioned into resolvable and non-resolvable parts based upon the cutoff between the propagating and evanescent fields. Operating under the Born approximation, we develop a beam-forming on transmit approach to direct the energy into either the propagating or evanescent parts of the spectrum. In this manner, we may individually interrogate the propagating and evanescent regions of the object spectrum.

  18. Instrumentation for Laue diffraction (invited)

    NASA Astrophysics Data System (ADS)

    Helliwell, J. R.; Harrop, S.; Habash, J.; Magorrian, B. G.; Allinson, N. M.; Gomez, D.; Helliwell, M.; Derewenda, Z.; Cruickshank, D. W. J.

    1989-07-01

    Single-crystal x-ray diffraction data can be measured very quickly in Laue geometry compared with monochromatic methods. Alternatively, this gain factor can be used instead to reduce the sample volume for a fixed exposure time. In the latter case especially, there is a critical need to control parasitic scatter in the Laue camera. The use of Laue geometry as a means of quantitative data acquisition required the solution of some fundamental problems. The so-called ``overlapping orders problem'' has been found not to be limiting. It can be shown that the bulk of the Laue spots are single order, provided dhkl<2dmin where dhkl is the interplanar spacing and dmin is the resolution limit of the data. In addition, empirical wavelength normalization is required. This can be achieved by using the symmetry of the diffraction pattern. The fact that different equivalents occur at different wavelengths means that the differences in these intensities can be used to establish the ``λ curve.'' Successful wavelength normalization to date has used a relatively broad-band pass. The multiplicity distribution is the histogram of the number of spots of a given order. This distribution is determined by the ratio λmax/λmin (λmax =maximum wavelength, λmin =minimum wavelength in the beam). λmax is determined by the use of any filters in the beamline. λmin is determined either by the spectral curve or a critical cutoff if a mirror is used. A mirror can be usefully introduced to enhance the multiplicity distribution in favor of single wavelength spots or to focus the white beam; so far only vertical focussing has been used. The detector options used to date have been photographic film, Fuji image plate (at Photon Factory)/Kodak storage phosphor (at Cornell) and charge coupled device (CCD) (at Daresbury). It is useful to consider the joint theoretical spatial and energy distribution of spots in defining the detector specification and geometry. To date, we have processed Laue film data

  19. Probing young drinking water biofilms with hard and soft particles.

    PubMed

    Paris, Tony; Skali-Lami, Salaheddine; Block, Jean-Claude

    2009-01-01

    The aim of our study was to investigate, through the use of soft (Escherichia coli) and hard (polystyrene microspheres) particles, the distribution and persistence of allochthonous particles inoculated in drinking water flow chambers. Biofilms were allowed to grow for 7-10 months in tap water from Nancy's drinking water network and were composed of bacterial aggregates and filamentous fungi. Both model particles adhered almost exclusively on the biofilms (i.e. on the bacterial aggregates and on the filamentous structures) and not directly on the uncolonized walls (glass or Plexiglas). Biofilm age (i.e. bacterial density and biofilm properties) and convective-diffusion were found to govern particle accumulation: older biofilms and higher wall shear rates both increased the velocity and the amount of particle deposition on the biofilm. Persistence of the polystyrene particles was measured over a two-month period after inoculation. Accumulation amounts were found to be very different between hard and soft particles as only 0.03 per thousand of the soft particles inoculated accumulated in the biofilm against 0.3-0.8% for hard particles.

  20. Enthalpy versus Entropy: the Thermodynamic Origin of Hard Particle Ordering

    NASA Astrophysics Data System (ADS)

    Anthamatten, Mitchell; Chen, Shaw; Ou, Jane; Weinfeld, Jeffrey; Department of Chemical Engineering Team

    The topic of hard particle ordering transitions is important in the development of molecular to mesoscale materials with potential applications in biomedicine, catalysis, optoelectronics, and renewable energy. The first step toward deterministic materials design rests on understanding the thermodynamic nature of ordering transitions involving two phases in equilibrium. We apply classical thermodynamics to show that (i) first-order, hard particle ordering transitions are forbidden at constant volume; and that (ii) hard-particle ordering is driven by a loss in enthalpy through volume reduction that outweighs a concomitant entropy loss upon ordering. The traditional approach considers minimization of Helmholtz energy, at constant volume, whereas the current study exclusively focuses on equilibrium phase transitions and, therefore, targets minimization of Gibbs energy at constant pressure. The Gibbs energy platform offers physically intuitive interpretations consistent with existing computation and experiments. The prevalent idea of entropy-driven ordering at constant V is restricted to transitions from non-equilibrium initial states that have yet to be properly defined for quantification. Laboratory of Laser Energetics, DE-FC52-08NA28302.

  1. Cooperation induced by random sequential exclusion

    NASA Astrophysics Data System (ADS)

    Li, Kun; Cong, Rui; Wang, Long

    2016-06-01

    Social exclusion is a common and powerful tool to penalize deviators in human societies, and thus to effectively elevate collaborative efforts. Current models on the evolution of exclusion behaviors mostly assume that each peer excluder independently makes the decision to expel the defectors, but has no idea what others in the group would do or how the actual punishment effect will be. Thus, a more realistic model, random sequential exclusion, is proposed. In this mechanism, each excluder has to pay an extra scheduling cost and then all the excluders are arranged in a random order to implement the exclusion actions. If one free rider has already been excluded by an excluder, the remaining excluders will not participate in expelling this defector. We find that this mechanism can help stabilize cooperation under more unfavorable conditions than the normal peer exclusion can do, either in well-mixed population or on social networks. However, too large a scheduling cost may undermine the advantage of this mechanism. Our work validates the fact that collaborative practice among punishers plays an important role in further boosting cooperation.

  2. Exclusive Breastfeeding Experiences among Mexican American Women.

    PubMed

    Wambach, Karen; Domian, Elaine Williams; Page-Goertz, Sallie; Wurtz, Heather; Hoffman, Kelli

    2016-02-01

    According to the Centers for Disease Control and Prevention, Hispanic breastfeeding mothers begin early formula supplementation at higher rates than other ethnic groups, which can lead to shorter breastfeeding duration and decreased exclusive breastfeeding. Acculturation, the process of adopting beliefs and behaviors of another culture, appears to influence breastfeeding practices of Hispanic women in the United States. Little is known about Mexican American mothers' formula use and exclusive breastfeeding within the context of acculturation. Our study identified perceived benefits and barriers to exclusive breastfeeding and levels of acculturation among Mexican American women living in a Midwestern city. We used a qualitative descriptive design integrating Pender's Health Promotion Model concepts. Individual interviews were conducted in English or Spanish (N = 21). The revised Acculturation Rating Scale for Mexican Americans was used to examine acculturation levels. Acculturation scores indicated that the majority (66%) of the sample was "very Mexican oriented." Most women exclusively breastfed, with a few using early supplementation for "insufficient milk production." Three themes emerged: (1) It is natural that a woman give life and also provide the best food for her baby; (2) Breastfeeding is ultimately a woman's decision but is influenced by tradition, guidance, and encouragement; and (3) Breast milk is superior but life circumstances can challenge one's ability to breastfeed. Strong familial/cultural traditions supported and normalized breastfeeding. Barriers to exclusive breastfeeding were similar to breastfeeding women in general, in the United States. Findings support the need for culturally competent and individualized lactation care. © The Author(s) 2015.

  3. Calculation of Loudspeaker Cabinet Diffraction and Correction

    NASA Astrophysics Data System (ADS)

    Le, Yi; Shen, Yong; Xia, Jie

    2011-10-01

    A method of calculating the cabinet edge diffractions for loudspeaker driver when mounted in an enclosure is proposed, based on the extended Biot—Tolstoy—Medwin model. Up to the third order, cabinet diffractions are discussed in detail and the diffractive effects on the radiated sound field of the loudspeaker system are quantitatively described, with a correction function built to compensate for the diffractive interference. The method is applied to a practical loudspeaker enclosure that has rectangular facets. The diffractive effects of the cabinet on the forward sound radiation are investigated and predictions of the calculations show quite good agreements with experimental measurements.

  4. Near-field diffraction of chirped gratings.

    PubMed

    Sanchez-Brea, Luis Miguel; Torcal-Milla, Francisco Jose; Morlanes, Tomas

    2016-09-01

    In this Letter, we analyze the near-field diffraction pattern produced by chirped gratings. An intuitive analytical interpretation of the generated diffraction orders is proposed. Several interesting properties of the near-field diffraction pattern can be determined, such as the period of the fringes and its visibility. Diffraction orders present different widths and also, some of them present focusing properties. The width, location, and depth of focus of the converging diffraction orders are also determined. The analytical expressions are compared to numerical simulation and experimental results, showing a high agreement.

  5. Molecular hardness and softness, local hardness and softness, hardness and softness kernels, and relations among these quantities

    NASA Astrophysics Data System (ADS)

    Berkowitz, Max; Parr, Robert G.

    1988-02-01

    Hardness and softness kernels η(r,r') and s(r,r') are defined for the ground state of an atomic or molecular electronic system, and the previously defined local hardness and softness η(r) and s(r) and global hardness and softness η and S are obtained from them. The physical meaning of s(r), as a charge capacitance, is discussed (following Huheey and Politzer), and two alternative ``hardness'' indices are identified and briefly discussed.

  6. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, M.S.; Schuster, G.J.; Skorpik, J.R.

    1997-07-08

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

  7. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, Morris S.; Schuster, George J.; Skorpik, James R.

    1997-01-01

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

  8. Transpecific microsatellites for hard pines.

    PubMed

    Shepherd, M.; Cross, M.; Maguire, L.; Dieters, J.; Williams, G.; Henry, J.

    2002-04-01

    Microsatellites are difficult to recover from large plant genomes so cross-specific utilisation is an important source of markers. Fifty microsatellites were tested for cross-specific amplification and polymorphism to two New World hard pine species, slash pine ( Pinus elliottii var. elliottii) and Caribbean pine ( P. caribaea var. hondurensis). Twenty-nine (58%) markers amplified in both hard pine species, and 23 of these 29 were polymorphic. Soft pine (subgenus Strobus) microsatellite markers did amplify, but none were polymorphic. Pinus elliottii var. elliottii and P. caribaea var. hondurensis showed mutational changes in the flanking regions and the repeat motif that were informative for Pinus spp. phylogenetic relationships. Most allele length variation could be attributed to variability in repeat unit number. There was no evidence for ascertainment bias.

  9. Microwave assisted hard rock cutting

    DOEpatents

    Lindroth, David P.; Morrell, Roger J.; Blair, James R.

    1991-01-01

    An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

  10. Rad-Hard Silicon Detectors

    NASA Astrophysics Data System (ADS)

    Giorgi, Marco

    2005-06-01

    For the next generation of High Energy Physics (HEP) Experiments silicon microstrip detectors working in harsh radiation environments with excellent performances are necessary. The irradiation causes bulk and surface damages that modify the electrical properties of the detector. Solutions like AC coupled strips, overhanging metal contact, <100> crystal lattice orientation, low resistivity n-bulk and Oxygenated substrate are studied for rad-hard detectors. The paper presents an outlook of these technologies.

  11. Schwannoma of the hard palate

    PubMed Central

    Sahoo, Pradyumna Kumar; Mandal, Palash Kumar; Ghosh, Saradindu

    2014-01-01

    Schwannomas are benign encapsulated perineural tumors. The head and neck region is the most common site. Intraoral origin is seen in only 1% of cases, tongue being the most common site; its location in the palate is rare. We report a case of hard-palate schwannoma with bony erosion which was immunohistochemically confirmed. The tumor was excised completely intraorally. After two months of follow-up, the defect was found to be completely covered with palatal mucosa. PMID:25298716

  12. Hard-to-fill vacancies.

    PubMed

    Williams, Ruth

    2010-09-29

    Skills for Health has launched a set of resources to help healthcare employers tackle hard-to-fill entry-level vacancies and provide sustainable employment for local unemployed people. The Sector Employability Toolkit aims to reduce recruitment and retention costs for entry-level posts and repare people for employment through pre-job training programmes, and support employers to develop local partnerships to gain access to wider pools of candidates and funding streams.

  13. Ion exclusion chromatography of aromatic acids.

    PubMed

    Mansour, Fotouh R; Kirkpatrick, Christine L; Danielson, Neil D

    2013-08-01

    The determination of aromatic acids by ion exclusion chromatography is challenging due to peak tailing and the long retention time of hydrophobic solutes. This review discusses the retention mechanisms and the factors affecting retention, eluents and detection methods used in ion exclusion chromatography of aromatic acids such as mono-, di-, tri- and tetra-carboxylic acids, amino acids, sulfonates and phenol. In addition, the different approaches used to improve the chromatographic separation of these compounds are also discussed. These approaches include introducing an internal gradient of the ionic strength, using vacancy ion exclusion chromatography, employing a hydrophilic cation exchange resin or adding a modifier such as heptanol to the dilute sulfuric acid mobile phase. The applications of these methods in the analysis of aromatic acids are provided with a table summarizing the stationary phases, the mobile phases and the detection methods.

  14. 42 CFR 402.13 - Penalty, assessment, and exclusion not exclusive.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Penalty, assessment, and exclusion not exclusive. 402.13 Section 402.13 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND... imposed under this part are in addition to any other penalties prescribed by law....

  15. 42 CFR 1003.108 - Penalty, assessment, and exclusion not exclusive.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Penalty, assessment, and exclusion not exclusive. 1003.108 Section 1003.108 Public Health OFFICE OF INSPECTOR GENERAL-HEALTH CARE, DEPARTMENT OF HEALTH... this part are in addition to any other penalties prescribed by law....

  16. 42 CFR 1003.108 - Penalty, assessment, and exclusion not exclusive.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Penalty, assessment, and exclusion not exclusive. 1003.108 Section 1003.108 Public Health OFFICE OF INSPECTOR GENERAL-HEALTH CARE, DEPARTMENT OF HEALTH... this part are in addition to any other penalties prescribed by law....

  17. 42 CFR 402.13 - Penalty, assessment, and exclusion not exclusive.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false Penalty, assessment, and exclusion not exclusive. 402.13 Section 402.13 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND... imposed under this part are in addition to any other penalties prescribed by law....

  18. 75 FR 65614 - Availability for Non-Exclusive or Partially-Exclusive Licensing of Invention Concerning...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... Department of the Army Availability for Non-Exclusive or Partially-Exclusive Licensing of Invention Concerning Obstetrics Simulation and Training Method System AGENCY: Department of the Army, DoD. ACTION... States Government, as represented by the Secretary of the Army, has rights to this invention....

  19. Diffractive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  20. Nanostructural Evolution of Hard Turning Layers in Carburized Steel

    NASA Astrophysics Data System (ADS)

    Bedekar, Vikram

    The mechanisms of failure for components subjected to contact fatigue are sensitive to the structure and properties of the material surface. Although, the bulk material properties are determined by the steel making, forming and the heat treatment; the near surface material properties are altered during final material removal processes such as hard turning or grinding. Therefore, the ability to optimize, modulate and predict the near surface properties during final metal removal operations would be extremely useful in the enhancement of service life of a component. Hard machining is known to induce severely deformed layers causing dramatic microstructural transformations. These transformations occur via grain refinement or thermal phenomena depending upon cutting conditions. The aim of this work is to engineer the near surface nanoscale structure and properties during hard turning by altering strain, strain rate, temperature and incoming microstructure. The near surface material transformations due to hard turning were studied on carburized SAE 8620 bearing steel. Variations in parent material microstructures were introduced by altering the retained austenite content. The strain, strain rate and temperature achieved during final metal cutting were altered by varying insert geometry, insert wear and cutting speed. The subsurface evolution was quantified by a series of advanced characterization techniques such as transmission electron microscopy (TEM), glancing angle X-ray diffraction (GAXRD), X-ray stress evaluation and nanoindentation which were coupled with numerical modeling. Results showed that the grain size of the nanocrystalline near surface microstructure can be effectively controlled by altering the insert geometry, insert wear, cutting speed and the incoming microstructure. It was also evident that the near surface retained austenite decreased at lower cutting speed indicating transformation due to plastic deformation, while it increased at higher cutting